MFH

[FreeBSD/FreeBSD.git] / sys / netinet / sctp_input.c

/*-
 * Copyright (c) 2001-2008, by Cisco Systems, Inc. All rights reserved.
 * Copyright (c) 2008-2012, by Randall Stewart. All rights reserved.
 * Copyright (c) 2008-2012, by Michael Tuexen. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * a) Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 * b) Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the distribution.
 *
 * c) Neither the name of Cisco Systems, Inc. nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include <netinet/sctp_os.h>
#include <netinet/sctp_var.h>
#include <netinet/sctp_sysctl.h>
#include <netinet/sctp_pcb.h>
#include <netinet/sctp_header.h>
#include <netinet/sctputil.h>
#include <netinet/sctp_output.h>
#include <netinet/sctp_input.h>
#include <netinet/sctp_auth.h>
#include <netinet/sctp_indata.h>
#include <netinet/sctp_asconf.h>
#include <netinet/sctp_bsd_addr.h>
#include <netinet/sctp_timer.h>
#include <netinet/sctp_crc32.h>
#if defined(INET) || defined(INET6)
#include <netinet/udp.h>
#endif
#include <sys/smp.h>



static void
sctp_stop_all_cookie_timers(struct sctp_tcb *stcb)
{
        struct sctp_nets *net;

        /*
         * This now not only stops all cookie timers it also stops any INIT
         * timers as well. This will make sure that the timers are stopped
         * in all collision cases.
         */
        SCTP_TCB_LOCK_ASSERT(stcb);
        TAILQ_FOREACH(net, &stcb->asoc.nets, sctp_next) {
                if (net->rxt_timer.type == SCTP_TIMER_TYPE_COOKIE) {
                        sctp_timer_stop(SCTP_TIMER_TYPE_COOKIE,
                            stcb->sctp_ep,
                            stcb,
                            net, SCTP_FROM_SCTP_INPUT + SCTP_LOC_1);
                } else if (net->rxt_timer.type == SCTP_TIMER_TYPE_INIT) {
                        sctp_timer_stop(SCTP_TIMER_TYPE_INIT,
                            stcb->sctp_ep,
                            stcb,
                            net, SCTP_FROM_SCTP_INPUT + SCTP_LOC_2);
                }
        }
}

/* INIT handler */
static void
sctp_handle_init(struct mbuf *m, int iphlen, int offset,
    struct sockaddr *src, struct sockaddr *dst, struct sctphdr *sh,
    struct sctp_init_chunk *cp, struct sctp_inpcb *inp,
    struct sctp_tcb *stcb, struct sctp_nets *net, int *abort_no_unlock,
    uint8_t mflowtype, uint32_t mflowid,
    uint32_t vrf_id, uint16_t port)
{
        struct sctp_init *init;
        struct mbuf *op_err;

        SCTPDBG(SCTP_DEBUG_INPUT2, "sctp_handle_init: handling INIT tcb:%p\n",
            (void *)stcb);
        if (stcb == NULL) {
                SCTP_INP_RLOCK(inp);
        }
        /* validate length */
        if (ntohs(cp->ch.chunk_length) < sizeof(struct sctp_init_chunk)) {
                op_err = sctp_generate_cause(SCTP_CAUSE_INVALID_PARAM, "");
                sctp_abort_association(inp, stcb, m, iphlen, src, dst, sh, op_err,
                    mflowtype, mflowid,
                    vrf_id, port);
                if (stcb)
                        *abort_no_unlock = 1;
                goto outnow;
        }
        /* validate parameters */
        init = &cp->init;
        if (init->initiate_tag == 0) {
                /* protocol error... send abort */
                op_err = sctp_generate_cause(SCTP_CAUSE_INVALID_PARAM, "");
                sctp_abort_association(inp, stcb, m, iphlen, src, dst, sh, op_err,
                    mflowtype, mflowid,
                    vrf_id, port);
                if (stcb)
                        *abort_no_unlock = 1;
                goto outnow;
        }
        if (ntohl(init->a_rwnd) < SCTP_MIN_RWND) {
                /* invalid parameter... send abort */
                op_err = sctp_generate_cause(SCTP_CAUSE_INVALID_PARAM, "");
                sctp_abort_association(inp, stcb, m, iphlen, src, dst, sh, op_err,
                    mflowtype, mflowid,
                    vrf_id, port);
                if (stcb)
                        *abort_no_unlock = 1;
                goto outnow;
        }
        if (init->num_inbound_streams == 0) {
                /* protocol error... send abort */
                op_err = sctp_generate_cause(SCTP_CAUSE_INVALID_PARAM, "");
                sctp_abort_association(inp, stcb, m, iphlen, src, dst, sh, op_err,
                    mflowtype, mflowid,
                    vrf_id, port);
                if (stcb)
                        *abort_no_unlock = 1;
                goto outnow;
        }
        if (init->num_outbound_streams == 0) {
                /* protocol error... send abort */
                op_err = sctp_generate_cause(SCTP_CAUSE_INVALID_PARAM, "");
                sctp_abort_association(inp, stcb, m, iphlen, src, dst, sh, op_err,
                    mflowtype, mflowid,
                    vrf_id, port);
                if (stcb)
                        *abort_no_unlock = 1;
                goto outnow;
        }
        if (sctp_validate_init_auth_params(m, offset + sizeof(*cp),
            offset + ntohs(cp->ch.chunk_length))) {
                /* auth parameter(s) error... send abort */
                op_err = sctp_generate_cause(SCTP_BASE_SYSCTL(sctp_diag_info_code),
                    "Problem with AUTH parameters");
                sctp_abort_association(inp, stcb, m, iphlen, src, dst, sh, op_err,
                    mflowtype, mflowid,
                    vrf_id, port);
                if (stcb)
                        *abort_no_unlock = 1;
                goto outnow;
        }
        /*
         * We are only accepting if we have a socket with positive
         * so_qlimit.
         */
        if ((stcb == NULL) &&
            ((inp->sctp_flags & SCTP_PCB_FLAGS_SOCKET_GONE) ||
            (inp->sctp_flags & SCTP_PCB_FLAGS_SOCKET_ALLGONE) ||
            (inp->sctp_socket == NULL) ||
            (inp->sctp_socket->so_qlimit == 0))) {
                /*
                 * FIX ME ?? What about TCP model and we have a
                 * match/restart case? Actually no fix is needed. the lookup
                 * will always find the existing assoc so stcb would not be
                 * NULL. It may be questionable to do this since we COULD
                 * just send back the INIT-ACK and hope that the app did
                 * accept()'s by the time the COOKIE was sent. But there is
                 * a price to pay for COOKIE generation and I don't want to
                 * pay it on the chance that the app will actually do some
                 * accepts(). The App just looses and should NOT be in this
                 * state :-)
                 */
                if (SCTP_BASE_SYSCTL(sctp_blackhole) == 0) {
                        op_err = sctp_generate_cause(SCTP_BASE_SYSCTL(sctp_diag_info_code),
                            "No listener");
                        sctp_send_abort(m, iphlen, src, dst, sh, 0, op_err,
                            mflowtype, mflowid, inp->fibnum,
                            vrf_id, port);
                }
                goto outnow;
        }
        if ((stcb != NULL) &&
            (SCTP_GET_STATE(&stcb->asoc) == SCTP_STATE_SHUTDOWN_ACK_SENT)) {
                SCTPDBG(SCTP_DEBUG_INPUT3, "sctp_handle_init: sending SHUTDOWN-ACK\n");
                sctp_send_shutdown_ack(stcb, NULL);
                sctp_chunk_output(inp, stcb, SCTP_OUTPUT_FROM_CONTROL_PROC, SCTP_SO_NOT_LOCKED);
        } else {
                SCTPDBG(SCTP_DEBUG_INPUT3, "sctp_handle_init: sending INIT-ACK\n");
                sctp_send_initiate_ack(inp, stcb, net, m, iphlen, offset,
                    src, dst, sh, cp,
                    mflowtype, mflowid,
                    vrf_id, port,
                    ((stcb == NULL) ? SCTP_HOLDS_LOCK : SCTP_NOT_LOCKED));
        }
outnow:
        if (stcb == NULL) {
                SCTP_INP_RUNLOCK(inp);
        }
}

/*
 * process peer "INIT/INIT-ACK" chunk returns value < 0 on error
 */

int
sctp_is_there_unsent_data(struct sctp_tcb *stcb, int so_locked
#if !defined(__APPLE__) && !defined(SCTP_SO_LOCK_TESTING)
    SCTP_UNUSED
#endif
)
{
        int unsent_data = 0;
        unsigned int i;
        struct sctp_stream_queue_pending *sp;
        struct sctp_association *asoc;

        /*
         * This function returns the number of streams that have true unsent
         * data on them. Note that as it looks through it will clean up any
         * places that have old data that has been sent but left at top of
         * stream queue.
         */
        asoc = &stcb->asoc;
        SCTP_TCB_SEND_LOCK(stcb);
        if (!stcb->asoc.ss_functions.sctp_ss_is_empty(stcb, asoc)) {
                /* Check to see if some data queued */
                for (i = 0; i < stcb->asoc.streamoutcnt; i++) {
                        /* sa_ignore FREED_MEMORY */
                        sp = TAILQ_FIRST(&stcb->asoc.strmout[i].outqueue);
                        if (sp == NULL) {
                                continue;
                        }
                        if ((sp->msg_is_complete) &&
                            (sp->length == 0) &&
                            (sp->sender_all_done)) {
                                /*
                                 * We are doing differed cleanup. Last time
                                 * through when we took all the data the
                                 * sender_all_done was not set.
                                 */
                                if (sp->put_last_out == 0) {
                                        SCTP_PRINTF("Gak, put out entire msg with NO end!-1\n");
                                        SCTP_PRINTF("sender_done:%d len:%d msg_comp:%d put_last_out:%d\n",
                                            sp->sender_all_done,
                                            sp->length,
                                            sp->msg_is_complete,
                                            sp->put_last_out);
                                }
                                atomic_subtract_int(&stcb->asoc.stream_queue_cnt, 1);
                                TAILQ_REMOVE(&stcb->asoc.strmout[i].outqueue, sp, next);
                                if (sp->net) {
                                        sctp_free_remote_addr(sp->net);
                                        sp->net = NULL;
                                }
                                if (sp->data) {
                                        sctp_m_freem(sp->data);
                                        sp->data = NULL;
                                }
                                sctp_free_a_strmoq(stcb, sp, so_locked);
                        } else {
                                unsent_data++;
                                break;
                        }
                }
        }
        SCTP_TCB_SEND_UNLOCK(stcb);
        return (unsent_data);
}

static int
sctp_process_init(struct sctp_init_chunk *cp, struct sctp_tcb *stcb)
{
        struct sctp_init *init;
        struct sctp_association *asoc;
        struct sctp_nets *lnet;
        unsigned int i;

        init = &cp->init;
        asoc = &stcb->asoc;
        /* save off parameters */
        asoc->peer_vtag = ntohl(init->initiate_tag);
        asoc->peers_rwnd = ntohl(init->a_rwnd);
        /* init tsn's */
        asoc->highest_tsn_inside_map = asoc->asconf_seq_in = ntohl(init->initial_tsn) - 1;

        if (!TAILQ_EMPTY(&asoc->nets)) {
                /* update any ssthresh's that may have a default */
                TAILQ_FOREACH(lnet, &asoc->nets, sctp_next) {
                        lnet->ssthresh = asoc->peers_rwnd;
                        if (SCTP_BASE_SYSCTL(sctp_logging_level) & (SCTP_CWND_MONITOR_ENABLE | SCTP_CWND_LOGGING_ENABLE)) {
                                sctp_log_cwnd(stcb, lnet, 0, SCTP_CWND_INITIALIZATION);
                        }
                }
        }
        SCTP_TCB_SEND_LOCK(stcb);
        if (asoc->pre_open_streams > ntohs(init->num_inbound_streams)) {
                unsigned int newcnt;
                struct sctp_stream_out *outs;
                struct sctp_stream_queue_pending *sp, *nsp;
                struct sctp_tmit_chunk *chk, *nchk;

                /* abandon the upper streams */
                newcnt = ntohs(init->num_inbound_streams);
                TAILQ_FOREACH_SAFE(chk, &asoc->send_queue, sctp_next, nchk) {
                        if (chk->rec.data.stream_number >= newcnt) {
                                TAILQ_REMOVE(&asoc->send_queue, chk, sctp_next);
                                asoc->send_queue_cnt--;
                                if (asoc->strmout[chk->rec.data.stream_number].chunks_on_queues > 0) {
                                        asoc->strmout[chk->rec.data.stream_number].chunks_on_queues--;
#ifdef INVARIANTS
                                } else {
                                        panic("No chunks on the queues for sid %u.", chk->rec.data.stream_number);
#endif
                                }
                                if (chk->data != NULL) {
                                        sctp_free_bufspace(stcb, asoc, chk, 1);
                                        sctp_ulp_notify(SCTP_NOTIFY_UNSENT_DG_FAIL, stcb,
                                            0, chk, SCTP_SO_NOT_LOCKED);
                                        if (chk->data) {
                                                sctp_m_freem(chk->data);
                                                chk->data = NULL;
                                        }
                                }
                                sctp_free_a_chunk(stcb, chk, SCTP_SO_NOT_LOCKED);
                                /* sa_ignore FREED_MEMORY */
                        }
                }
                if (asoc->strmout) {
                        for (i = newcnt; i < asoc->pre_open_streams; i++) {
                                outs = &asoc->strmout[i];
                                TAILQ_FOREACH_SAFE(sp, &outs->outqueue, next, nsp) {
                                        TAILQ_REMOVE(&outs->outqueue, sp, next);
                                        asoc->stream_queue_cnt--;
                                        sctp_ulp_notify(SCTP_NOTIFY_SPECIAL_SP_FAIL,
                                            stcb, 0, sp, SCTP_SO_NOT_LOCKED);
                                        if (sp->data) {
                                                sctp_m_freem(sp->data);
                                                sp->data = NULL;
                                        }
                                        if (sp->net) {
                                                sctp_free_remote_addr(sp->net);
                                                sp->net = NULL;
                                        }
                                        /* Free the chunk */
                                        sctp_free_a_strmoq(stcb, sp, SCTP_SO_NOT_LOCKED);
                                        /* sa_ignore FREED_MEMORY */
                                }
                                outs->state = SCTP_STREAM_CLOSED;
                        }
                }
                /* cut back the count */
                asoc->pre_open_streams = newcnt;
        }
        SCTP_TCB_SEND_UNLOCK(stcb);
        asoc->streamoutcnt = asoc->pre_open_streams;
        for (i = 0; i < asoc->streamoutcnt; i++) {
                asoc->strmout[i].state = SCTP_STREAM_OPEN;
        }
        /* EY - nr_sack: initialize highest tsn in nr_mapping_array */
        asoc->highest_tsn_inside_nr_map = asoc->highest_tsn_inside_map;
        if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_MAP_LOGGING_ENABLE) {
                sctp_log_map(0, 5, asoc->highest_tsn_inside_map, SCTP_MAP_SLIDE_RESULT);
        }
        /* This is the next one we expect */
        asoc->str_reset_seq_in = asoc->asconf_seq_in + 1;

        asoc->mapping_array_base_tsn = ntohl(init->initial_tsn);
        asoc->tsn_last_delivered = asoc->cumulative_tsn = asoc->asconf_seq_in;

        asoc->advanced_peer_ack_point = asoc->last_acked_seq;
        /* open the requested streams */

        if (asoc->strmin != NULL) {
                /* Free the old ones */
                struct sctp_queued_to_read *ctl, *nctl;

                for (i = 0; i < asoc->streamincnt; i++) {
                        TAILQ_FOREACH_SAFE(ctl, &asoc->strmin[i].inqueue, next, nctl) {
                                TAILQ_REMOVE(&asoc->strmin[i].inqueue, ctl, next);
                                sctp_free_remote_addr(ctl->whoFrom);
                                ctl->whoFrom = NULL;
                                sctp_m_freem(ctl->data);
                                ctl->data = NULL;
                                sctp_free_a_readq(stcb, ctl);
                        }
                }
                SCTP_FREE(asoc->strmin, SCTP_M_STRMI);
        }
        if (asoc->max_inbound_streams > ntohs(init->num_outbound_streams)) {
                asoc->streamincnt = ntohs(init->num_outbound_streams);
        } else {
                asoc->streamincnt = asoc->max_inbound_streams;
        }
        SCTP_MALLOC(asoc->strmin, struct sctp_stream_in *, asoc->streamincnt *
            sizeof(struct sctp_stream_in), SCTP_M_STRMI);
        if (asoc->strmin == NULL) {
                /* we didn't get memory for the streams! */
                SCTPDBG(SCTP_DEBUG_INPUT2, "process_init: couldn't get memory for the streams!\n");
                return (-1);
        }
        for (i = 0; i < asoc->streamincnt; i++) {
                asoc->strmin[i].stream_no = i;
                asoc->strmin[i].last_sequence_delivered = 0xffff;
                TAILQ_INIT(&asoc->strmin[i].inqueue);
                asoc->strmin[i].delivery_started = 0;
        }
        /*
         * load_address_from_init will put the addresses into the
         * association when the COOKIE is processed or the INIT-ACK is
         * processed. Both types of COOKIE's existing and new call this
         * routine. It will remove addresses that are no longer in the
         * association (for the restarting case where addresses are
         * removed). Up front when the INIT arrives we will discard it if it
         * is a restart and new addresses have been added.
         */
        /* sa_ignore MEMLEAK */
        return (0);
}

/*
 * INIT-ACK message processing/consumption returns value < 0 on error
 */
static int
sctp_process_init_ack(struct mbuf *m, int iphlen, int offset,
    struct sockaddr *src, struct sockaddr *dst, struct sctphdr *sh,
    struct sctp_init_ack_chunk *cp, struct sctp_tcb *stcb,
    struct sctp_nets *net, int *abort_no_unlock,
    uint8_t mflowtype, uint32_t mflowid,
    uint32_t vrf_id)
{
        struct sctp_association *asoc;
        struct mbuf *op_err;
        int retval, abort_flag;
        uint32_t initack_limit;
        int nat_friendly = 0;

        /* First verify that we have no illegal param's */
        abort_flag = 0;

        op_err = sctp_arethere_unrecognized_parameters(m,
            (offset + sizeof(struct sctp_init_chunk)),
            &abort_flag, (struct sctp_chunkhdr *)cp, &nat_friendly);
        if (abort_flag) {
                /* Send an abort and notify peer */
                sctp_abort_an_association(stcb->sctp_ep, stcb, op_err, SCTP_SO_NOT_LOCKED);
                *abort_no_unlock = 1;
                return (-1);
        }
        asoc = &stcb->asoc;
        asoc->peer_supports_nat = (uint8_t) nat_friendly;
        /* process the peer's parameters in the INIT-ACK */
        retval = sctp_process_init((struct sctp_init_chunk *)cp, stcb);
        if (retval < 0) {
                return (retval);
        }
        initack_limit = offset + ntohs(cp->ch.chunk_length);
        /* load all addresses */
        if ((retval = sctp_load_addresses_from_init(stcb, m,
            (offset + sizeof(struct sctp_init_chunk)), initack_limit,
            src, dst, NULL))) {
                op_err = sctp_generate_cause(SCTP_BASE_SYSCTL(sctp_diag_info_code),
                    "Problem with address parameters");
                SCTPDBG(SCTP_DEBUG_INPUT1,
                    "Load addresses from INIT causes an abort %d\n",
                    retval);
                sctp_abort_association(stcb->sctp_ep, stcb, m, iphlen,
                    src, dst, sh, op_err,
                    mflowtype, mflowid,
                    vrf_id, net->port);
                *abort_no_unlock = 1;
                return (-1);
        }
        /* if the peer doesn't support asconf, flush the asconf queue */
        if (asoc->asconf_supported == 0) {
                struct sctp_asconf_addr *param, *nparam;

                TAILQ_FOREACH_SAFE(param, &asoc->asconf_queue, next, nparam) {
                        TAILQ_REMOVE(&asoc->asconf_queue, param, next);
                        SCTP_FREE(param, SCTP_M_ASC_ADDR);
                }
        }
        stcb->asoc.peer_hmac_id = sctp_negotiate_hmacid(stcb->asoc.peer_hmacs,
            stcb->asoc.local_hmacs);
        if (op_err) {
                sctp_queue_op_err(stcb, op_err);
                /* queuing will steal away the mbuf chain to the out queue */
                op_err = NULL;
        }
        /* extract the cookie and queue it to "echo" it back... */
        if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_THRESHOLD_LOGGING) {
                sctp_misc_ints(SCTP_THRESHOLD_CLEAR,
                    stcb->asoc.overall_error_count,
                    0,
                    SCTP_FROM_SCTP_INPUT,
                    __LINE__);
        }
        stcb->asoc.overall_error_count = 0;
        net->error_count = 0;

        /*
         * Cancel the INIT timer, We do this first before queueing the
         * cookie. We always cancel at the primary to assue that we are
         * canceling the timer started by the INIT which always goes to the
         * primary.
         */
        sctp_timer_stop(SCTP_TIMER_TYPE_INIT, stcb->sctp_ep, stcb,
            asoc->primary_destination, SCTP_FROM_SCTP_INPUT + SCTP_LOC_3);

        /* calculate the RTO */
        net->RTO = sctp_calculate_rto(stcb, asoc, net, &asoc->time_entered, sctp_align_safe_nocopy,
            SCTP_RTT_FROM_NON_DATA);
        retval = sctp_send_cookie_echo(m, offset, stcb, net);
        if (retval < 0) {
                /*
                 * No cookie, we probably should send a op error. But in any
                 * case if there is no cookie in the INIT-ACK, we can
                 * abandon the peer, its broke.
                 */
                if (retval == -3) {
                        uint16_t len;

                        len = (uint16_t) (sizeof(struct sctp_error_missing_param) + sizeof(uint16_t));
                        /* We abort with an error of missing mandatory param */
                        op_err = sctp_get_mbuf_for_msg(len, 0, M_NOWAIT, 1, MT_DATA);
                        if (op_err != NULL) {
                                struct sctp_error_missing_param *cause;

                                SCTP_BUF_LEN(op_err) = len;
                                cause = mtod(op_err, struct sctp_error_missing_param *);
                                /* Subtract the reserved param */
                                cause->cause.code = htons(SCTP_CAUSE_MISSING_PARAM);
                                cause->cause.length = htons(len);
                                cause->num_missing_params = htonl(1);
                                cause->type[0] = htons(SCTP_STATE_COOKIE);
                        }
                        sctp_abort_association(stcb->sctp_ep, stcb, m, iphlen,
                            src, dst, sh, op_err,
                            mflowtype, mflowid,
                            vrf_id, net->port);
                        *abort_no_unlock = 1;
                }
                return (retval);
        }
        return (0);
}

static void
sctp_handle_heartbeat_ack(struct sctp_heartbeat_chunk *cp,
    struct sctp_tcb *stcb, struct sctp_nets *net)
{
        union sctp_sockstore store;
        struct sctp_nets *r_net, *f_net;
        struct timeval tv;
        int req_prim = 0;
        uint16_t old_error_counter;

        if (ntohs(cp->ch.chunk_length) != sizeof(struct sctp_heartbeat_chunk)) {
                /* Invalid length */
                return;
        }
        memset(&store, 0, sizeof(store));
        switch (cp->heartbeat.hb_info.addr_family) {
#ifdef INET
        case AF_INET:
                if (cp->heartbeat.hb_info.addr_len == sizeof(struct sockaddr_in)) {
                        store.sin.sin_family = cp->heartbeat.hb_info.addr_family;
                        store.sin.sin_len = cp->heartbeat.hb_info.addr_len;
                        store.sin.sin_port = stcb->rport;
                        memcpy(&store.sin.sin_addr, cp->heartbeat.hb_info.address,
                            sizeof(store.sin.sin_addr));
                } else {
                        return;
                }
                break;
#endif
#ifdef INET6
        case AF_INET6:
                if (cp->heartbeat.hb_info.addr_len == sizeof(struct sockaddr_in6)) {
                        store.sin6.sin6_family = cp->heartbeat.hb_info.addr_family;
                        store.sin6.sin6_len = cp->heartbeat.hb_info.addr_len;
                        store.sin6.sin6_port = stcb->rport;
                        memcpy(&store.sin6.sin6_addr, cp->heartbeat.hb_info.address, sizeof(struct in6_addr));
                } else {
                        return;
                }
                break;
#endif
        default:
                return;
        }
        r_net = sctp_findnet(stcb, &store.sa);
        if (r_net == NULL) {
                SCTPDBG(SCTP_DEBUG_INPUT1, "Huh? I can't find the address I sent it to, discard\n");
                return;
        }
        if ((r_net && (r_net->dest_state & SCTP_ADDR_UNCONFIRMED)) &&
            (r_net->heartbeat_random1 == cp->heartbeat.hb_info.random_value1) &&
            (r_net->heartbeat_random2 == cp->heartbeat.hb_info.random_value2)) {
                /*
                 * If the its a HB and it's random value is correct when can
                 * confirm the destination.
                 */
                r_net->dest_state &= ~SCTP_ADDR_UNCONFIRMED;
                if (r_net->dest_state & SCTP_ADDR_REQ_PRIMARY) {
                        stcb->asoc.primary_destination = r_net;
                        r_net->dest_state &= ~SCTP_ADDR_REQ_PRIMARY;
                        f_net = TAILQ_FIRST(&stcb->asoc.nets);
                        if (f_net != r_net) {
                                /*
                                 * first one on the list is NOT the primary
                                 * sctp_cmpaddr() is much more efficent if
                                 * the primary is the first on the list,
                                 * make it so.
                                 */
                                TAILQ_REMOVE(&stcb->asoc.nets, r_net, sctp_next);
                                TAILQ_INSERT_HEAD(&stcb->asoc.nets, r_net, sctp_next);
                        }
                        req_prim = 1;
                }
                sctp_ulp_notify(SCTP_NOTIFY_INTERFACE_CONFIRMED,
                    stcb, 0, (void *)r_net, SCTP_SO_NOT_LOCKED);
                sctp_timer_stop(SCTP_TIMER_TYPE_HEARTBEAT, stcb->sctp_ep, stcb,
                    r_net, SCTP_FROM_SCTP_INPUT + SCTP_LOC_4);
                sctp_timer_start(SCTP_TIMER_TYPE_HEARTBEAT, stcb->sctp_ep, stcb, r_net);
        }
        old_error_counter = r_net->error_count;
        r_net->error_count = 0;
        r_net->hb_responded = 1;
        tv.tv_sec = cp->heartbeat.hb_info.time_value_1;
        tv.tv_usec = cp->heartbeat.hb_info.time_value_2;
        /* Now lets do a RTO with this */
        r_net->RTO = sctp_calculate_rto(stcb, &stcb->asoc, r_net, &tv, sctp_align_safe_nocopy,
            SCTP_RTT_FROM_NON_DATA);
        if (!(r_net->dest_state & SCTP_ADDR_REACHABLE)) {
                r_net->dest_state |= SCTP_ADDR_REACHABLE;
                sctp_ulp_notify(SCTP_NOTIFY_INTERFACE_UP, stcb,
                    0, (void *)r_net, SCTP_SO_NOT_LOCKED);
        }
        if (r_net->dest_state & SCTP_ADDR_PF) {
                r_net->dest_state &= ~SCTP_ADDR_PF;
                stcb->asoc.cc_functions.sctp_cwnd_update_exit_pf(stcb, net);
        }
        if (old_error_counter > 0) {
                sctp_timer_stop(SCTP_TIMER_TYPE_HEARTBEAT, stcb->sctp_ep,
                    stcb, r_net, SCTP_FROM_SCTP_INPUT + SCTP_LOC_5);
                sctp_timer_start(SCTP_TIMER_TYPE_HEARTBEAT, stcb->sctp_ep, stcb, r_net);
        }
        if (r_net == stcb->asoc.primary_destination) {
                if (stcb->asoc.alternate) {
                        /* release the alternate, primary is good */
                        sctp_free_remote_addr(stcb->asoc.alternate);
                        stcb->asoc.alternate = NULL;
                }
        }
        /* Mobility adaptation */
        if (req_prim) {
                if ((sctp_is_mobility_feature_on(stcb->sctp_ep,
                    SCTP_MOBILITY_BASE) ||
                    sctp_is_mobility_feature_on(stcb->sctp_ep,
                    SCTP_MOBILITY_FASTHANDOFF)) &&
                    sctp_is_mobility_feature_on(stcb->sctp_ep,
                    SCTP_MOBILITY_PRIM_DELETED)) {

                        sctp_timer_stop(SCTP_TIMER_TYPE_PRIM_DELETED,
                            stcb->sctp_ep, stcb, NULL,
                            SCTP_FROM_SCTP_INPUT + SCTP_LOC_6);
                        if (sctp_is_mobility_feature_on(stcb->sctp_ep,
                            SCTP_MOBILITY_FASTHANDOFF)) {
                                sctp_assoc_immediate_retrans(stcb,
                                    stcb->asoc.primary_destination);
                        }
                        if (sctp_is_mobility_feature_on(stcb->sctp_ep,
                            SCTP_MOBILITY_BASE)) {
                                sctp_move_chunks_from_net(stcb,
                                    stcb->asoc.deleted_primary);
                        }
                        sctp_delete_prim_timer(stcb->sctp_ep, stcb,
                            stcb->asoc.deleted_primary);
                }
        }
}

static int
sctp_handle_nat_colliding_state(struct sctp_tcb *stcb)
{
        /*
         * return 0 means we want you to proceed with the abort non-zero
         * means no abort processing
         */
        struct sctpasochead *head;

        if (SCTP_GET_STATE(&stcb->asoc) == SCTP_STATE_COOKIE_WAIT) {
                /* generate a new vtag and send init */
                LIST_REMOVE(stcb, sctp_asocs);
                stcb->asoc.my_vtag = sctp_select_a_tag(stcb->sctp_ep, stcb->sctp_ep->sctp_lport, stcb->rport, 1);
                head = &SCTP_BASE_INFO(sctp_asochash)[SCTP_PCBHASH_ASOC(stcb->asoc.my_vtag, SCTP_BASE_INFO(hashasocmark))];
                /*
                 * put it in the bucket in the vtag hash of assoc's for the
                 * system
                 */
                LIST_INSERT_HEAD(head, stcb, sctp_asocs);
                sctp_send_initiate(stcb->sctp_ep, stcb, SCTP_SO_NOT_LOCKED);
                return (1);
        }
        if (SCTP_GET_STATE(&stcb->asoc) == SCTP_STATE_COOKIE_ECHOED) {
                /*
                 * treat like a case where the cookie expired i.e.: - dump
                 * current cookie. - generate a new vtag. - resend init.
                 */
                /* generate a new vtag and send init */
                LIST_REMOVE(stcb, sctp_asocs);
                stcb->asoc.state &= ~SCTP_STATE_COOKIE_ECHOED;
                stcb->asoc.state |= SCTP_STATE_COOKIE_WAIT;
                sctp_stop_all_cookie_timers(stcb);
                sctp_toss_old_cookies(stcb, &stcb->asoc);
                stcb->asoc.my_vtag = sctp_select_a_tag(stcb->sctp_ep, stcb->sctp_ep->sctp_lport, stcb->rport, 1);
                head = &SCTP_BASE_INFO(sctp_asochash)[SCTP_PCBHASH_ASOC(stcb->asoc.my_vtag, SCTP_BASE_INFO(hashasocmark))];
                /*
                 * put it in the bucket in the vtag hash of assoc's for the
                 * system
                 */
                LIST_INSERT_HEAD(head, stcb, sctp_asocs);
                sctp_send_initiate(stcb->sctp_ep, stcb, SCTP_SO_NOT_LOCKED);
                return (1);
        }
        return (0);
}

static int
sctp_handle_nat_missing_state(struct sctp_tcb *stcb,
    struct sctp_nets *net)
{
        /*
         * return 0 means we want you to proceed with the abort non-zero
         * means no abort processing
         */
        if (stcb->asoc.auth_supported == 0) {
                SCTPDBG(SCTP_DEBUG_INPUT2, "sctp_handle_nat_missing_state: Peer does not support AUTH, cannot send an asconf\n");
                return (0);
        }
        sctp_asconf_send_nat_state_update(stcb, net);
        return (1);
}


static void
sctp_handle_abort(struct sctp_abort_chunk *abort,
    struct sctp_tcb *stcb, struct sctp_nets *net)
{
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
        struct socket *so;

#endif
        uint16_t len;
        uint16_t error;

        SCTPDBG(SCTP_DEBUG_INPUT2, "sctp_handle_abort: handling ABORT\n");
        if (stcb == NULL)
                return;

        len = ntohs(abort->ch.chunk_length);
        if (len > sizeof(struct sctp_chunkhdr)) {
                /*
                 * Need to check the cause codes for our two magic nat
                 * aborts which don't kill the assoc necessarily.
                 */
                struct sctp_gen_error_cause *cause;

                cause = (struct sctp_gen_error_cause *)(abort + 1);
                error = ntohs(cause->code);
                if (error == SCTP_CAUSE_NAT_COLLIDING_STATE) {
                        SCTPDBG(SCTP_DEBUG_INPUT2, "Received Colliding state abort flags:%x\n",
                            abort->ch.chunk_flags);
                        if (sctp_handle_nat_colliding_state(stcb)) {
                                return;
                        }
                } else if (error == SCTP_CAUSE_NAT_MISSING_STATE) {
                        SCTPDBG(SCTP_DEBUG_INPUT2, "Received missing state abort flags:%x\n",
                            abort->ch.chunk_flags);
                        if (sctp_handle_nat_missing_state(stcb, net)) {
                                return;
                        }
                }
        } else {
                error = 0;
        }
        /* stop any receive timers */
        sctp_timer_stop(SCTP_TIMER_TYPE_RECV, stcb->sctp_ep, stcb, net,
            SCTP_FROM_SCTP_INPUT + SCTP_LOC_7);
        /* notify user of the abort and clean up... */
        sctp_abort_notification(stcb, 1, error, abort, SCTP_SO_NOT_LOCKED);
        /* free the tcb */
        SCTP_STAT_INCR_COUNTER32(sctps_aborted);
        if ((SCTP_GET_STATE(&stcb->asoc) == SCTP_STATE_OPEN) ||
            (SCTP_GET_STATE(&stcb->asoc) == SCTP_STATE_SHUTDOWN_RECEIVED)) {
                SCTP_STAT_DECR_GAUGE32(sctps_currestab);
        }
#ifdef SCTP_ASOCLOG_OF_TSNS
        sctp_print_out_track_log(stcb);
#endif
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
        so = SCTP_INP_SO(stcb->sctp_ep);
        atomic_add_int(&stcb->asoc.refcnt, 1);
        SCTP_TCB_UNLOCK(stcb);
        SCTP_SOCKET_LOCK(so, 1);
        SCTP_TCB_LOCK(stcb);
        atomic_subtract_int(&stcb->asoc.refcnt, 1);
#endif
        stcb->asoc.state |= SCTP_STATE_WAS_ABORTED;
        (void)sctp_free_assoc(stcb->sctp_ep, stcb, SCTP_NORMAL_PROC,
            SCTP_FROM_SCTP_INPUT + SCTP_LOC_8);
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
        SCTP_SOCKET_UNLOCK(so, 1);
#endif
        SCTPDBG(SCTP_DEBUG_INPUT2, "sctp_handle_abort: finished\n");
}

static void
sctp_start_net_timers(struct sctp_tcb *stcb)
{
        uint32_t cnt_hb_sent;
        struct sctp_nets *net;

        cnt_hb_sent = 0;
        TAILQ_FOREACH(net, &stcb->asoc.nets, sctp_next) {
                /*
                 * For each network start: 1) A pmtu timer. 2) A HB timer 3)
                 * If the dest in unconfirmed send a hb as well if under
                 * max_hb_burst have been sent.
                 */
                sctp_timer_start(SCTP_TIMER_TYPE_PATHMTURAISE, stcb->sctp_ep, stcb, net);
                sctp_timer_start(SCTP_TIMER_TYPE_HEARTBEAT, stcb->sctp_ep, stcb, net);
                if ((net->dest_state & SCTP_ADDR_UNCONFIRMED) &&
                    (cnt_hb_sent < SCTP_BASE_SYSCTL(sctp_hb_maxburst))) {
                        sctp_send_hb(stcb, net, SCTP_SO_NOT_LOCKED);
                        cnt_hb_sent++;
                }
        }
        if (cnt_hb_sent) {
                sctp_chunk_output(stcb->sctp_ep, stcb,
                    SCTP_OUTPUT_FROM_COOKIE_ACK,
                    SCTP_SO_NOT_LOCKED);
        }
}


static void
sctp_handle_shutdown(struct sctp_shutdown_chunk *cp,
    struct sctp_tcb *stcb, struct sctp_nets *net, int *abort_flag)
{
        struct sctp_association *asoc;
        int some_on_streamwheel;
        int old_state;

#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
        struct socket *so;

#endif

        SCTPDBG(SCTP_DEBUG_INPUT2,
            "sctp_handle_shutdown: handling SHUTDOWN\n");
        if (stcb == NULL)
                return;
        asoc = &stcb->asoc;
        if ((SCTP_GET_STATE(asoc) == SCTP_STATE_COOKIE_WAIT) ||
            (SCTP_GET_STATE(asoc) == SCTP_STATE_COOKIE_ECHOED)) {
                return;
        }
        if (ntohs(cp->ch.chunk_length) != sizeof(struct sctp_shutdown_chunk)) {
                /* Shutdown NOT the expected size */
                return;
        }
        old_state = SCTP_GET_STATE(asoc);
        sctp_update_acked(stcb, cp, abort_flag);
        if (*abort_flag) {
                return;
        }
        if (asoc->control_pdapi) {
                /*
                 * With a normal shutdown we assume the end of last record.
                 */
                SCTP_INP_READ_LOCK(stcb->sctp_ep);
                asoc->control_pdapi->end_added = 1;
                asoc->control_pdapi->pdapi_aborted = 1;
                asoc->control_pdapi = NULL;
                SCTP_INP_READ_UNLOCK(stcb->sctp_ep);
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                so = SCTP_INP_SO(stcb->sctp_ep);
                atomic_add_int(&stcb->asoc.refcnt, 1);
                SCTP_TCB_UNLOCK(stcb);
                SCTP_SOCKET_LOCK(so, 1);
                SCTP_TCB_LOCK(stcb);
                atomic_subtract_int(&stcb->asoc.refcnt, 1);
                if (stcb->asoc.state & SCTP_STATE_CLOSED_SOCKET) {
                        /* assoc was freed while we were unlocked */
                        SCTP_SOCKET_UNLOCK(so, 1);
                        return;
                }
#endif
                if (stcb->sctp_socket) {
                        sctp_sorwakeup(stcb->sctp_ep, stcb->sctp_socket);
                }
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                SCTP_SOCKET_UNLOCK(so, 1);
#endif
        }
        /* goto SHUTDOWN_RECEIVED state to block new requests */
        if (stcb->sctp_socket) {
                if ((SCTP_GET_STATE(asoc) != SCTP_STATE_SHUTDOWN_RECEIVED) &&
                    (SCTP_GET_STATE(asoc) != SCTP_STATE_SHUTDOWN_ACK_SENT) &&
                    (SCTP_GET_STATE(asoc) != SCTP_STATE_SHUTDOWN_SENT)) {
                        SCTP_SET_STATE(asoc, SCTP_STATE_SHUTDOWN_RECEIVED);
                        SCTP_CLEAR_SUBSTATE(asoc, SCTP_STATE_SHUTDOWN_PENDING);
                        /*
                         * notify upper layer that peer has initiated a
                         * shutdown
                         */
                        sctp_ulp_notify(SCTP_NOTIFY_PEER_SHUTDOWN, stcb, 0, NULL, SCTP_SO_NOT_LOCKED);

                        /* reset time */
                        (void)SCTP_GETTIME_TIMEVAL(&asoc->time_entered);
                }
        }
        if (SCTP_GET_STATE(asoc) == SCTP_STATE_SHUTDOWN_SENT) {
                /*
                 * stop the shutdown timer, since we WILL move to
                 * SHUTDOWN-ACK-SENT.
                 */
                sctp_timer_stop(SCTP_TIMER_TYPE_SHUTDOWN, stcb->sctp_ep, stcb,
                    net, SCTP_FROM_SCTP_INPUT + SCTP_LOC_9);
        }
        /* Now is there unsent data on a stream somewhere? */
        some_on_streamwheel = sctp_is_there_unsent_data(stcb, SCTP_SO_NOT_LOCKED);

        if (!TAILQ_EMPTY(&asoc->send_queue) ||
            !TAILQ_EMPTY(&asoc->sent_queue) ||
            some_on_streamwheel) {
                /* By returning we will push more data out */
                return;
        } else {
                /* no outstanding data to send, so move on... */
                /* send SHUTDOWN-ACK */
                /* move to SHUTDOWN-ACK-SENT state */
                if ((SCTP_GET_STATE(asoc) == SCTP_STATE_OPEN) ||
                    (SCTP_GET_STATE(asoc) == SCTP_STATE_SHUTDOWN_RECEIVED)) {
                        SCTP_STAT_DECR_GAUGE32(sctps_currestab);
                }
                SCTP_CLEAR_SUBSTATE(asoc, SCTP_STATE_SHUTDOWN_PENDING);
                if (SCTP_GET_STATE(asoc) != SCTP_STATE_SHUTDOWN_ACK_SENT) {
                        SCTP_SET_STATE(asoc, SCTP_STATE_SHUTDOWN_ACK_SENT);
                        sctp_stop_timers_for_shutdown(stcb);
                        sctp_send_shutdown_ack(stcb, net);
                        sctp_timer_start(SCTP_TIMER_TYPE_SHUTDOWNACK,
                            stcb->sctp_ep, stcb, net);
                } else if (old_state == SCTP_STATE_SHUTDOWN_ACK_SENT) {
                        sctp_send_shutdown_ack(stcb, net);
                }
        }
}

static void
sctp_handle_shutdown_ack(struct sctp_shutdown_ack_chunk *cp SCTP_UNUSED,
    struct sctp_tcb *stcb,
    struct sctp_nets *net)
{
        struct sctp_association *asoc;

#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
        struct socket *so;

        so = SCTP_INP_SO(stcb->sctp_ep);
#endif
        SCTPDBG(SCTP_DEBUG_INPUT2,
            "sctp_handle_shutdown_ack: handling SHUTDOWN ACK\n");
        if (stcb == NULL)
                return;

        asoc = &stcb->asoc;
        /* process according to association state */
        if ((SCTP_GET_STATE(asoc) == SCTP_STATE_COOKIE_WAIT) ||
            (SCTP_GET_STATE(asoc) == SCTP_STATE_COOKIE_ECHOED)) {
                /* unexpected SHUTDOWN-ACK... do OOTB handling... */
                sctp_send_shutdown_complete(stcb, net, 1);
                SCTP_TCB_UNLOCK(stcb);
                return;
        }
        if ((SCTP_GET_STATE(asoc) != SCTP_STATE_SHUTDOWN_SENT) &&
            (SCTP_GET_STATE(asoc) != SCTP_STATE_SHUTDOWN_ACK_SENT)) {
                /* unexpected SHUTDOWN-ACK... so ignore... */
                SCTP_TCB_UNLOCK(stcb);
                return;
        }
        if (asoc->control_pdapi) {
                /*
                 * With a normal shutdown we assume the end of last record.
                 */
                SCTP_INP_READ_LOCK(stcb->sctp_ep);
                asoc->control_pdapi->end_added = 1;
                asoc->control_pdapi->pdapi_aborted = 1;
                asoc->control_pdapi = NULL;
                SCTP_INP_READ_UNLOCK(stcb->sctp_ep);
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                atomic_add_int(&stcb->asoc.refcnt, 1);
                SCTP_TCB_UNLOCK(stcb);
                SCTP_SOCKET_LOCK(so, 1);
                SCTP_TCB_LOCK(stcb);
                atomic_subtract_int(&stcb->asoc.refcnt, 1);
                if (stcb->asoc.state & SCTP_STATE_CLOSED_SOCKET) {
                        /* assoc was freed while we were unlocked */
                        SCTP_SOCKET_UNLOCK(so, 1);
                        return;
                }
#endif
                sctp_sorwakeup(stcb->sctp_ep, stcb->sctp_socket);
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                SCTP_SOCKET_UNLOCK(so, 1);
#endif
        }
#ifdef INVARIANTS
        if (!TAILQ_EMPTY(&asoc->send_queue) ||
            !TAILQ_EMPTY(&asoc->sent_queue) ||
            !stcb->asoc.ss_functions.sctp_ss_is_empty(stcb, asoc)) {
                panic("Queues are not empty when handling SHUTDOWN-ACK");
        }
#endif
        /* stop the timer */
        sctp_timer_stop(SCTP_TIMER_TYPE_SHUTDOWN, stcb->sctp_ep, stcb, net,
            SCTP_FROM_SCTP_INPUT + SCTP_LOC_10);
        /* send SHUTDOWN-COMPLETE */
        sctp_send_shutdown_complete(stcb, net, 0);
        /* notify upper layer protocol */
        if (stcb->sctp_socket) {
                if ((stcb->sctp_ep->sctp_flags & SCTP_PCB_FLAGS_TCPTYPE) ||
                    (stcb->sctp_ep->sctp_flags & SCTP_PCB_FLAGS_IN_TCPPOOL)) {
                        stcb->sctp_socket->so_snd.sb_cc = 0;
                }
                sctp_ulp_notify(SCTP_NOTIFY_ASSOC_DOWN, stcb, 0, NULL, SCTP_SO_NOT_LOCKED);
        }
        SCTP_STAT_INCR_COUNTER32(sctps_shutdown);
        /* free the TCB but first save off the ep */
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
        atomic_add_int(&stcb->asoc.refcnt, 1);
        SCTP_TCB_UNLOCK(stcb);
        SCTP_SOCKET_LOCK(so, 1);
        SCTP_TCB_LOCK(stcb);
        atomic_subtract_int(&stcb->asoc.refcnt, 1);
#endif
        (void)sctp_free_assoc(stcb->sctp_ep, stcb, SCTP_NORMAL_PROC,
            SCTP_FROM_SCTP_INPUT + SCTP_LOC_11);
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
        SCTP_SOCKET_UNLOCK(so, 1);
#endif
}

/*
 * Skip past the param header and then we will find the chunk that caused the
 * problem. There are two possiblities ASCONF or FWD-TSN other than that and
 * our peer must be broken.
 */
static void
sctp_process_unrecog_chunk(struct sctp_tcb *stcb, struct sctp_paramhdr *phdr,
    struct sctp_nets *net)
{
        struct sctp_chunkhdr *chk;

        chk = (struct sctp_chunkhdr *)((caddr_t)phdr + sizeof(*phdr));
        switch (chk->chunk_type) {
        case SCTP_ASCONF_ACK:
        case SCTP_ASCONF:
                sctp_asconf_cleanup(stcb, net);
                break;
        case SCTP_FORWARD_CUM_TSN:
                stcb->asoc.prsctp_supported = 0;
                break;
        default:
                SCTPDBG(SCTP_DEBUG_INPUT2,
                    "Peer does not support chunk type %d(%x)??\n",
                    chk->chunk_type, (uint32_t) chk->chunk_type);
                break;
        }
}

/*
 * Skip past the param header and then we will find the param that caused the
 * problem.  There are a number of param's in a ASCONF OR the prsctp param
 * these will turn of specific features.
 * XXX: Is this the right thing to do?
 */
static void
sctp_process_unrecog_param(struct sctp_tcb *stcb, struct sctp_paramhdr *phdr)
{
        struct sctp_paramhdr *pbad;

        pbad = phdr + 1;
        switch (ntohs(pbad->param_type)) {
                /* pr-sctp draft */
        case SCTP_PRSCTP_SUPPORTED:
                stcb->asoc.prsctp_supported = 0;
                break;
        case SCTP_SUPPORTED_CHUNK_EXT:
                break;
                /* draft-ietf-tsvwg-addip-sctp */
        case SCTP_HAS_NAT_SUPPORT:
                stcb->asoc.peer_supports_nat = 0;
                break;
        case SCTP_ADD_IP_ADDRESS:
        case SCTP_DEL_IP_ADDRESS:
        case SCTP_SET_PRIM_ADDR:
                stcb->asoc.asconf_supported = 0;
                break;
        case SCTP_SUCCESS_REPORT:
        case SCTP_ERROR_CAUSE_IND:
                SCTPDBG(SCTP_DEBUG_INPUT2, "Huh, the peer does not support success? or error cause?\n");
                SCTPDBG(SCTP_DEBUG_INPUT2,
                    "Turning off ASCONF to this strange peer\n");
                stcb->asoc.asconf_supported = 0;
                break;
        default:
                SCTPDBG(SCTP_DEBUG_INPUT2,
                    "Peer does not support param type %d(%x)??\n",
                    pbad->param_type, (uint32_t) pbad->param_type);
                break;
        }
}

static int
sctp_handle_error(struct sctp_chunkhdr *ch,
    struct sctp_tcb *stcb, struct sctp_nets *net)
{
        int chklen;
        struct sctp_paramhdr *phdr;
        uint16_t error, error_type;
        uint16_t error_len;
        struct sctp_association *asoc;
        int adjust;

#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
        struct socket *so;

#endif

        /* parse through all of the errors and process */
        asoc = &stcb->asoc;
        phdr = (struct sctp_paramhdr *)((caddr_t)ch +
            sizeof(struct sctp_chunkhdr));
        chklen = ntohs(ch->chunk_length) - sizeof(struct sctp_chunkhdr);
        error = 0;
        while ((size_t)chklen >= sizeof(struct sctp_paramhdr)) {
                /* Process an Error Cause */
                error_type = ntohs(phdr->param_type);
                error_len = ntohs(phdr->param_length);
                if ((error_len > chklen) || (error_len == 0)) {
                        /* invalid param length for this param */
                        SCTPDBG(SCTP_DEBUG_INPUT1, "Bogus length in error param- chunk left:%d errorlen:%d\n",
                            chklen, error_len);
                        return (0);
                }
                if (error == 0) {
                        /* report the first error cause */
                        error = error_type;
                }
                switch (error_type) {
                case SCTP_CAUSE_INVALID_STREAM:
                case SCTP_CAUSE_MISSING_PARAM:
                case SCTP_CAUSE_INVALID_PARAM:
                case SCTP_CAUSE_NO_USER_DATA:
                        SCTPDBG(SCTP_DEBUG_INPUT1, "Software error we got a %d back? We have a bug :/ (or do they?)\n",
                            error_type);
                        break;
                case SCTP_CAUSE_NAT_COLLIDING_STATE:
                        SCTPDBG(SCTP_DEBUG_INPUT2, "Received Colliding state abort flags:%x\n",
                            ch->chunk_flags);
                        if (sctp_handle_nat_colliding_state(stcb)) {
                                return (0);
                        }
                        break;
                case SCTP_CAUSE_NAT_MISSING_STATE:
                        SCTPDBG(SCTP_DEBUG_INPUT2, "Received missing state abort flags:%x\n",
                            ch->chunk_flags);
                        if (sctp_handle_nat_missing_state(stcb, net)) {
                                return (0);
                        }
                        break;
                case SCTP_CAUSE_STALE_COOKIE:
                        /*
                         * We only act if we have echoed a cookie and are
                         * waiting.
                         */
                        if (SCTP_GET_STATE(asoc) == SCTP_STATE_COOKIE_ECHOED) {
                                int *p;

                                p = (int *)((caddr_t)phdr + sizeof(*phdr));
                                /* Save the time doubled */
                                asoc->cookie_preserve_req = ntohl(*p) << 1;
                                asoc->stale_cookie_count++;
                                if (asoc->stale_cookie_count >
                                    asoc->max_init_times) {
                                        sctp_abort_notification(stcb, 0, 0, NULL, SCTP_SO_NOT_LOCKED);
                                        /* now free the asoc */
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                                        so = SCTP_INP_SO(stcb->sctp_ep);
                                        atomic_add_int(&stcb->asoc.refcnt, 1);
                                        SCTP_TCB_UNLOCK(stcb);
                                        SCTP_SOCKET_LOCK(so, 1);
                                        SCTP_TCB_LOCK(stcb);
                                        atomic_subtract_int(&stcb->asoc.refcnt, 1);
#endif
                                        (void)sctp_free_assoc(stcb->sctp_ep, stcb, SCTP_NORMAL_PROC,
                                            SCTP_FROM_SCTP_INPUT + SCTP_LOC_12);
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                                        SCTP_SOCKET_UNLOCK(so, 1);
#endif
                                        return (-1);
                                }
                                /* blast back to INIT state */
                                sctp_toss_old_cookies(stcb, &stcb->asoc);
                                asoc->state &= ~SCTP_STATE_COOKIE_ECHOED;
                                asoc->state |= SCTP_STATE_COOKIE_WAIT;
                                sctp_stop_all_cookie_timers(stcb);
                                sctp_send_initiate(stcb->sctp_ep, stcb, SCTP_SO_NOT_LOCKED);
                        }
                        break;
                case SCTP_CAUSE_UNRESOLVABLE_ADDR:
                        /*
                         * Nothing we can do here, we don't do hostname
                         * addresses so if the peer does not like my IPv6
                         * (or IPv4 for that matter) it does not matter. If
                         * they don't support that type of address, they can
                         * NOT possibly get that packet type... i.e. with no
                         * IPv6 you can't recieve a IPv6 packet. so we can
                         * safely ignore this one. If we ever added support
                         * for HOSTNAME Addresses, then we would need to do
                         * something here.
                         */
                        break;
                case SCTP_CAUSE_UNRECOG_CHUNK:
                        sctp_process_unrecog_chunk(stcb, phdr, net);
                        break;
                case SCTP_CAUSE_UNRECOG_PARAM:
                        sctp_process_unrecog_param(stcb, phdr);
                        break;
                case SCTP_CAUSE_COOKIE_IN_SHUTDOWN:
                        /*
                         * We ignore this since the timer will drive out a
                         * new cookie anyway and there timer will drive us
                         * to send a SHUTDOWN_COMPLETE. We can't send one
                         * here since we don't have their tag.
                         */
                        break;
                case SCTP_CAUSE_DELETING_LAST_ADDR:
                case SCTP_CAUSE_RESOURCE_SHORTAGE:
                case SCTP_CAUSE_DELETING_SRC_ADDR:
                        /*
                         * We should NOT get these here, but in a
                         * ASCONF-ACK.
                         */
                        SCTPDBG(SCTP_DEBUG_INPUT2, "Peer sends ASCONF errors in a Operational Error?<%d>?\n",
                            error_type);
                        break;
                case SCTP_CAUSE_OUT_OF_RESC:
                        /*
                         * And what, pray tell do we do with the fact that
                         * the peer is out of resources? Not really sure we
                         * could do anything but abort. I suspect this
                         * should have came WITH an abort instead of in a
                         * OP-ERROR.
                         */
                        break;
                default:
                        SCTPDBG(SCTP_DEBUG_INPUT1, "sctp_handle_error: unknown error type = 0x%xh\n",
                            error_type);
                        break;
                }
                adjust = SCTP_SIZE32(error_len);
                chklen -= adjust;
                phdr = (struct sctp_paramhdr *)((caddr_t)phdr + adjust);
        }
        sctp_ulp_notify(SCTP_NOTIFY_REMOTE_ERROR, stcb, error, ch, SCTP_SO_NOT_LOCKED);
        return (0);
}

static int
sctp_handle_init_ack(struct mbuf *m, int iphlen, int offset,
    struct sockaddr *src, struct sockaddr *dst, struct sctphdr *sh,
    struct sctp_init_ack_chunk *cp, struct sctp_tcb *stcb,
    struct sctp_nets *net, int *abort_no_unlock,
    uint8_t mflowtype, uint32_t mflowid,
    uint32_t vrf_id)
{
        struct sctp_init_ack *init_ack;
        struct mbuf *op_err;

        SCTPDBG(SCTP_DEBUG_INPUT2,
            "sctp_handle_init_ack: handling INIT-ACK\n");

        if (stcb == NULL) {
                SCTPDBG(SCTP_DEBUG_INPUT2,
                    "sctp_handle_init_ack: TCB is null\n");
                return (-1);
        }
        if (ntohs(cp->ch.chunk_length) < sizeof(struct sctp_init_ack_chunk)) {
                /* Invalid length */
                op_err = sctp_generate_cause(SCTP_CAUSE_INVALID_PARAM, "");
                sctp_abort_association(stcb->sctp_ep, stcb, m, iphlen,
                    src, dst, sh, op_err,
                    mflowtype, mflowid,
                    vrf_id, net->port);
                *abort_no_unlock = 1;
                return (-1);
        }
        init_ack = &cp->init;
        /* validate parameters */
        if (init_ack->initiate_tag == 0) {
                /* protocol error... send an abort */
                op_err = sctp_generate_cause(SCTP_CAUSE_INVALID_PARAM, "");
                sctp_abort_association(stcb->sctp_ep, stcb, m, iphlen,
                    src, dst, sh, op_err,
                    mflowtype, mflowid,
                    vrf_id, net->port);
                *abort_no_unlock = 1;
                return (-1);
        }
        if (ntohl(init_ack->a_rwnd) < SCTP_MIN_RWND) {
                /* protocol error... send an abort */
                op_err = sctp_generate_cause(SCTP_CAUSE_INVALID_PARAM, "");
                sctp_abort_association(stcb->sctp_ep, stcb, m, iphlen,
                    src, dst, sh, op_err,
                    mflowtype, mflowid,
                    vrf_id, net->port);
                *abort_no_unlock = 1;
                return (-1);
        }
        if (init_ack->num_inbound_streams == 0) {
                /* protocol error... send an abort */
                op_err = sctp_generate_cause(SCTP_CAUSE_INVALID_PARAM, "");
                sctp_abort_association(stcb->sctp_ep, stcb, m, iphlen,
                    src, dst, sh, op_err,
                    mflowtype, mflowid,
                    vrf_id, net->port);
                *abort_no_unlock = 1;
                return (-1);
        }
        if (init_ack->num_outbound_streams == 0) {
                /* protocol error... send an abort */
                op_err = sctp_generate_cause(SCTP_CAUSE_INVALID_PARAM, "");
                sctp_abort_association(stcb->sctp_ep, stcb, m, iphlen,
                    src, dst, sh, op_err,
                    mflowtype, mflowid,
                    vrf_id, net->port);
                *abort_no_unlock = 1;
                return (-1);
        }
        /* process according to association state... */
        switch (stcb->asoc.state & SCTP_STATE_MASK) {
        case SCTP_STATE_COOKIE_WAIT:
                /* this is the expected state for this chunk */
                /* process the INIT-ACK parameters */
                if (stcb->asoc.primary_destination->dest_state &
                    SCTP_ADDR_UNCONFIRMED) {
                        /*
                         * The primary is where we sent the INIT, we can
                         * always consider it confirmed when the INIT-ACK is
                         * returned. Do this before we load addresses
                         * though.
                         */
                        stcb->asoc.primary_destination->dest_state &=
                            ~SCTP_ADDR_UNCONFIRMED;
                        sctp_ulp_notify(SCTP_NOTIFY_INTERFACE_CONFIRMED,
                            stcb, 0, (void *)stcb->asoc.primary_destination, SCTP_SO_NOT_LOCKED);
                }
                if (sctp_process_init_ack(m, iphlen, offset, src, dst, sh, cp, stcb,
                    net, abort_no_unlock,
                    mflowtype, mflowid,
                    vrf_id) < 0) {
                        /* error in parsing parameters */
                        return (-1);
                }
                /* update our state */
                SCTPDBG(SCTP_DEBUG_INPUT2, "moving to COOKIE-ECHOED state\n");
                SCTP_SET_STATE(&stcb->asoc, SCTP_STATE_COOKIE_ECHOED);

                /* reset the RTO calc */
                if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_THRESHOLD_LOGGING) {
                        sctp_misc_ints(SCTP_THRESHOLD_CLEAR,
                            stcb->asoc.overall_error_count,
                            0,
                            SCTP_FROM_SCTP_INPUT,
                            __LINE__);
                }
                stcb->asoc.overall_error_count = 0;
                (void)SCTP_GETTIME_TIMEVAL(&stcb->asoc.time_entered);
                /*
                 * collapse the init timer back in case of a exponential
                 * backoff
                 */
                sctp_timer_start(SCTP_TIMER_TYPE_COOKIE, stcb->sctp_ep,
                    stcb, net);
                /*
                 * the send at the end of the inbound data processing will
                 * cause the cookie to be sent
                 */
                break;
        case SCTP_STATE_SHUTDOWN_SENT:
                /* incorrect state... discard */
                break;
        case SCTP_STATE_COOKIE_ECHOED:
                /* incorrect state... discard */
                break;
        case SCTP_STATE_OPEN:
                /* incorrect state... discard */
                break;
        case SCTP_STATE_EMPTY:
        case SCTP_STATE_INUSE:
        default:
                /* incorrect state... discard */
                return (-1);
                break;
        }
        SCTPDBG(SCTP_DEBUG_INPUT1, "Leaving handle-init-ack end\n");
        return (0);
}

static struct sctp_tcb *
sctp_process_cookie_new(struct mbuf *m, int iphlen, int offset,
    struct sockaddr *src, struct sockaddr *dst,
    struct sctphdr *sh, struct sctp_state_cookie *cookie, int cookie_len,
    struct sctp_inpcb *inp, struct sctp_nets **netp,
    struct sockaddr *init_src, int *notification,
    int auth_skipped, uint32_t auth_offset, uint32_t auth_len,
    uint8_t mflowtype, uint32_t mflowid,
    uint32_t vrf_id, uint16_t port);


/*
 * handle a state cookie for an existing association m: input packet mbuf
 * chain-- assumes a pullup on IP/SCTP/COOKIE-ECHO chunk note: this is a
 * "split" mbuf and the cookie signature does not exist offset: offset into
 * mbuf to the cookie-echo chunk
 */
static struct sctp_tcb *
sctp_process_cookie_existing(struct mbuf *m, int iphlen, int offset,
    struct sockaddr *src, struct sockaddr *dst,
    struct sctphdr *sh, struct sctp_state_cookie *cookie, int cookie_len,
    struct sctp_inpcb *inp, struct sctp_tcb *stcb, struct sctp_nets **netp,
    struct sockaddr *init_src, int *notification,
    int auth_skipped, uint32_t auth_offset, uint32_t auth_len,
    uint8_t mflowtype, uint32_t mflowid,
    uint32_t vrf_id, uint16_t port)
{
        struct sctp_association *asoc;
        struct sctp_init_chunk *init_cp, init_buf;
        struct sctp_init_ack_chunk *initack_cp, initack_buf;
        struct sctp_nets *net;
        struct mbuf *op_err;
        int init_offset, initack_offset, i;
        int retval;
        int spec_flag = 0;
        uint32_t how_indx;

#if defined(SCTP_DETAILED_STR_STATS)
        int j;

#endif

        net = *netp;
        /* I know that the TCB is non-NULL from the caller */
        asoc = &stcb->asoc;
        for (how_indx = 0; how_indx < sizeof(asoc->cookie_how); how_indx++) {
                if (asoc->cookie_how[how_indx] == 0)
                        break;
        }
        if (how_indx < sizeof(asoc->cookie_how)) {
                asoc->cookie_how[how_indx] = 1;
        }
        if (SCTP_GET_STATE(asoc) == SCTP_STATE_SHUTDOWN_ACK_SENT) {
                /* SHUTDOWN came in after sending INIT-ACK */
                sctp_send_shutdown_ack(stcb, stcb->asoc.primary_destination);
                op_err = sctp_generate_cause(SCTP_CAUSE_COOKIE_IN_SHUTDOWN, "");
                sctp_send_operr_to(src, dst, sh, cookie->peers_vtag, op_err,
                    mflowtype, mflowid, inp->fibnum,
                    vrf_id, net->port);
                if (how_indx < sizeof(asoc->cookie_how))
                        asoc->cookie_how[how_indx] = 2;
                return (NULL);
        }
        /*
         * find and validate the INIT chunk in the cookie (peer's info) the
         * INIT should start after the cookie-echo header struct (chunk
         * header, state cookie header struct)
         */
        init_offset = offset += sizeof(struct sctp_cookie_echo_chunk);

        init_cp = (struct sctp_init_chunk *)
            sctp_m_getptr(m, init_offset, sizeof(struct sctp_init_chunk),
            (uint8_t *) & init_buf);
        if (init_cp == NULL) {
                /* could not pull a INIT chunk in cookie */
                return (NULL);
        }
        if (init_cp->ch.chunk_type != SCTP_INITIATION) {
                return (NULL);
        }
        /*
         * find and validate the INIT-ACK chunk in the cookie (my info) the
         * INIT-ACK follows the INIT chunk
         */
        initack_offset = init_offset + SCTP_SIZE32(ntohs(init_cp->ch.chunk_length));
        initack_cp = (struct sctp_init_ack_chunk *)
            sctp_m_getptr(m, initack_offset, sizeof(struct sctp_init_ack_chunk),
            (uint8_t *) & initack_buf);
        if (initack_cp == NULL) {
                /* could not pull INIT-ACK chunk in cookie */
                return (NULL);
        }
        if (initack_cp->ch.chunk_type != SCTP_INITIATION_ACK) {
                return (NULL);
        }
        if ((ntohl(initack_cp->init.initiate_tag) == asoc->my_vtag) &&
            (ntohl(init_cp->init.initiate_tag) == asoc->peer_vtag)) {
                /*
                 * case D in Section 5.2.4 Table 2: MMAA process accordingly
                 * to get into the OPEN state
                 */
                if (ntohl(initack_cp->init.initial_tsn) != asoc->init_seq_number) {
                        /*-
                         * Opps, this means that we somehow generated two vtag's
                         * the same. I.e. we did:
                         *  Us               Peer
                         *   <---INIT(tag=a)------
                         *   ----INIT-ACK(tag=t)-->
                         *   ----INIT(tag=t)------> *1
                         *   <---INIT-ACK(tag=a)---
                         *   <----CE(tag=t)------------- *2
                         *
                         * At point *1 we should be generating a different
                         * tag t'. Which means we would throw away the CE and send
                         * ours instead. Basically this is case C (throw away side).
                         */
                        if (how_indx < sizeof(asoc->cookie_how))
                                asoc->cookie_how[how_indx] = 17;
                        return (NULL);

                }
                switch (SCTP_GET_STATE(asoc)) {
                case SCTP_STATE_COOKIE_WAIT:
                case SCTP_STATE_COOKIE_ECHOED:
                        /*
                         * INIT was sent but got a COOKIE_ECHO with the
                         * correct tags... just accept it...but we must
                         * process the init so that we can make sure we have
                         * the right seq no's.
                         */
                        /* First we must process the INIT !! */
                        retval = sctp_process_init(init_cp, stcb);
                        if (retval < 0) {
                                if (how_indx < sizeof(asoc->cookie_how))
                                        asoc->cookie_how[how_indx] = 3;
                                return (NULL);
                        }
                        /* we have already processed the INIT so no problem */
                        sctp_timer_stop(SCTP_TIMER_TYPE_HEARTBEAT, inp,
                            stcb, net,
                            SCTP_FROM_SCTP_INPUT + SCTP_LOC_13);
                        sctp_timer_stop(SCTP_TIMER_TYPE_INIT, inp,
                            stcb, net,
                            SCTP_FROM_SCTP_INPUT + SCTP_LOC_14);
                        /* update current state */
                        if (SCTP_GET_STATE(asoc) == SCTP_STATE_COOKIE_ECHOED)
                                SCTP_STAT_INCR_COUNTER32(sctps_activeestab);
                        else
                                SCTP_STAT_INCR_COUNTER32(sctps_collisionestab);

                        SCTP_SET_STATE(asoc, SCTP_STATE_OPEN);
                        if (asoc->state & SCTP_STATE_SHUTDOWN_PENDING) {
                                sctp_timer_start(SCTP_TIMER_TYPE_SHUTDOWNGUARD,
                                    stcb->sctp_ep, stcb, asoc->primary_destination);
                        }
                        SCTP_STAT_INCR_GAUGE32(sctps_currestab);
                        sctp_stop_all_cookie_timers(stcb);
                        if (((stcb->sctp_ep->sctp_flags & SCTP_PCB_FLAGS_TCPTYPE) ||
                            (stcb->sctp_ep->sctp_flags & SCTP_PCB_FLAGS_IN_TCPPOOL)) &&
                            (inp->sctp_socket->so_qlimit == 0)
                            ) {
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                                struct socket *so;

#endif
                                /*
                                 * Here is where collision would go if we
                                 * did a connect() and instead got a
                                 * init/init-ack/cookie done before the
                                 * init-ack came back..
                                 */
                                stcb->sctp_ep->sctp_flags |=
                                    SCTP_PCB_FLAGS_CONNECTED;
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                                so = SCTP_INP_SO(stcb->sctp_ep);
                                atomic_add_int(&stcb->asoc.refcnt, 1);
                                SCTP_TCB_UNLOCK(stcb);
                                SCTP_SOCKET_LOCK(so, 1);
                                SCTP_TCB_LOCK(stcb);
                                atomic_add_int(&stcb->asoc.refcnt, -1);
                                if (stcb->asoc.state & SCTP_STATE_CLOSED_SOCKET) {
                                        SCTP_SOCKET_UNLOCK(so, 1);
                                        return (NULL);
                                }
#endif
                                soisconnected(stcb->sctp_socket);
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                                SCTP_SOCKET_UNLOCK(so, 1);
#endif
                        }
                        /* notify upper layer */
                        *notification = SCTP_NOTIFY_ASSOC_UP;
                        /*
                         * since we did not send a HB make sure we don't
                         * double things
                         */
                        net->hb_responded = 1;
                        net->RTO = sctp_calculate_rto(stcb, asoc, net,
                            &cookie->time_entered,
                            sctp_align_unsafe_makecopy,
                            SCTP_RTT_FROM_NON_DATA);

                        if (stcb->asoc.sctp_autoclose_ticks &&
                            (sctp_is_feature_on(inp, SCTP_PCB_FLAGS_AUTOCLOSE))) {
                                sctp_timer_start(SCTP_TIMER_TYPE_AUTOCLOSE,
                                    inp, stcb, NULL);
                        }
                        break;
                default:
                        /*
                         * we're in the OPEN state (or beyond), so peer must
                         * have simply lost the COOKIE-ACK
                         */
                        break;
                }               /* end switch */
                sctp_stop_all_cookie_timers(stcb);
                /*
                 * We ignore the return code here.. not sure if we should
                 * somehow abort.. but we do have an existing asoc. This
                 * really should not fail.
                 */
                if (sctp_load_addresses_from_init(stcb, m,
                    init_offset + sizeof(struct sctp_init_chunk),
                    initack_offset, src, dst, init_src)) {
                        if (how_indx < sizeof(asoc->cookie_how))
                                asoc->cookie_how[how_indx] = 4;
                        return (NULL);
                }
                /* respond with a COOKIE-ACK */
                sctp_toss_old_cookies(stcb, asoc);
                sctp_send_cookie_ack(stcb);
                if (how_indx < sizeof(asoc->cookie_how))
                        asoc->cookie_how[how_indx] = 5;
                return (stcb);
        }
        if (ntohl(initack_cp->init.initiate_tag) != asoc->my_vtag &&
            ntohl(init_cp->init.initiate_tag) == asoc->peer_vtag &&
            cookie->tie_tag_my_vtag == 0 &&
            cookie->tie_tag_peer_vtag == 0) {
                /*
                 * case C in Section 5.2.4 Table 2: XMOO silently discard
                 */
                if (how_indx < sizeof(asoc->cookie_how))
                        asoc->cookie_how[how_indx] = 6;
                return (NULL);
        }
        /*
         * If nat support, and the below and stcb is established, send back
         * a ABORT(colliding state) if we are established.
         */
        if ((SCTP_GET_STATE(asoc) == SCTP_STATE_OPEN) &&
            (asoc->peer_supports_nat) &&
            ((ntohl(initack_cp->init.initiate_tag) == asoc->my_vtag) &&
            ((ntohl(init_cp->init.initiate_tag) != asoc->peer_vtag) ||
            (asoc->peer_vtag == 0)))) {
                /*
                 * Special case - Peer's support nat. We may have two init's
                 * that we gave out the same tag on since one was not
                 * established.. i.e. we get INIT from host-1 behind the nat
                 * and we respond tag-a, we get a INIT from host-2 behind
                 * the nat and we get tag-a again. Then we bring up host-1
                 * (or 2's) assoc, Then comes the cookie from hsot-2 (or 1).
                 * Now we have colliding state. We must send an abort here
                 * with colliding state indication.
                 */
                op_err = sctp_generate_cause(SCTP_CAUSE_NAT_COLLIDING_STATE, "");
                sctp_send_abort(m, iphlen, src, dst, sh, 0, op_err,
                    mflowtype, mflowid, inp->fibnum,
                    vrf_id, port);
                return (NULL);
        }
        if ((ntohl(initack_cp->init.initiate_tag) == asoc->my_vtag) &&
            ((ntohl(init_cp->init.initiate_tag) != asoc->peer_vtag) ||
            (asoc->peer_vtag == 0))) {
                /*
                 * case B in Section 5.2.4 Table 2: MXAA or MOAA my info
                 * should be ok, re-accept peer info
                 */
                if (ntohl(initack_cp->init.initial_tsn) != asoc->init_seq_number) {
                        /*
                         * Extension of case C. If we hit this, then the
                         * random number generator returned the same vtag
                         * when we first sent our INIT-ACK and when we later
                         * sent our INIT. The side with the seq numbers that
                         * are different will be the one that normnally
                         * would have hit case C. This in effect "extends"
                         * our vtags in this collision case to be 64 bits.
                         * The same collision could occur aka you get both
                         * vtag and seq number the same twice in a row.. but
                         * is much less likely. If it did happen then we
                         * would proceed through and bring up the assoc.. we
                         * may end up with the wrong stream setup however..
                         * which would be bad.. but there is no way to
                         * tell.. until we send on a stream that does not
                         * exist :-)
                         */
                        if (how_indx < sizeof(asoc->cookie_how))
                                asoc->cookie_how[how_indx] = 7;

                        return (NULL);
                }
                if (how_indx < sizeof(asoc->cookie_how))
                        asoc->cookie_how[how_indx] = 8;
                sctp_timer_stop(SCTP_TIMER_TYPE_HEARTBEAT, inp, stcb, net,
                    SCTP_FROM_SCTP_INPUT + SCTP_LOC_15);
                sctp_stop_all_cookie_timers(stcb);
                /*
                 * since we did not send a HB make sure we don't double
                 * things
                 */
                net->hb_responded = 1;
                if (stcb->asoc.sctp_autoclose_ticks &&
                    sctp_is_feature_on(inp, SCTP_PCB_FLAGS_AUTOCLOSE)) {
                        sctp_timer_start(SCTP_TIMER_TYPE_AUTOCLOSE, inp, stcb,
                            NULL);
                }
                asoc->my_rwnd = ntohl(initack_cp->init.a_rwnd);
                asoc->pre_open_streams = ntohs(initack_cp->init.num_outbound_streams);

                if (ntohl(init_cp->init.initiate_tag) != asoc->peer_vtag) {
                        /*
                         * Ok the peer probably discarded our data (if we
                         * echoed a cookie+data). So anything on the
                         * sent_queue should be marked for retransmit, we
                         * may not get something to kick us so it COULD
                         * still take a timeout to move these.. but it can't
                         * hurt to mark them.
                         */
                        struct sctp_tmit_chunk *chk;

                        TAILQ_FOREACH(chk, &stcb->asoc.sent_queue, sctp_next) {
                                if (chk->sent < SCTP_DATAGRAM_RESEND) {
                                        chk->sent = SCTP_DATAGRAM_RESEND;
                                        sctp_flight_size_decrease(chk);
                                        sctp_total_flight_decrease(stcb, chk);
                                        sctp_ucount_incr(stcb->asoc.sent_queue_retran_cnt);
                                        spec_flag++;
                                }
                        }

                }
                /* process the INIT info (peer's info) */
                retval = sctp_process_init(init_cp, stcb);
                if (retval < 0) {
                        if (how_indx < sizeof(asoc->cookie_how))
                                asoc->cookie_how[how_indx] = 9;
                        return (NULL);
                }
                if (sctp_load_addresses_from_init(stcb, m,
                    init_offset + sizeof(struct sctp_init_chunk),
                    initack_offset, src, dst, init_src)) {
                        if (how_indx < sizeof(asoc->cookie_how))
                                asoc->cookie_how[how_indx] = 10;
                        return (NULL);
                }
                if ((asoc->state & SCTP_STATE_COOKIE_WAIT) ||
                    (asoc->state & SCTP_STATE_COOKIE_ECHOED)) {
                        *notification = SCTP_NOTIFY_ASSOC_UP;

                        if (((stcb->sctp_ep->sctp_flags & SCTP_PCB_FLAGS_TCPTYPE) ||
                            (stcb->sctp_ep->sctp_flags & SCTP_PCB_FLAGS_IN_TCPPOOL)) &&
                            (inp->sctp_socket->so_qlimit == 0)) {
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                                struct socket *so;

#endif
                                stcb->sctp_ep->sctp_flags |=
                                    SCTP_PCB_FLAGS_CONNECTED;
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                                so = SCTP_INP_SO(stcb->sctp_ep);
                                atomic_add_int(&stcb->asoc.refcnt, 1);
                                SCTP_TCB_UNLOCK(stcb);
                                SCTP_SOCKET_LOCK(so, 1);
                                SCTP_TCB_LOCK(stcb);
                                atomic_add_int(&stcb->asoc.refcnt, -1);
                                if (stcb->asoc.state & SCTP_STATE_CLOSED_SOCKET) {
                                        SCTP_SOCKET_UNLOCK(so, 1);
                                        return (NULL);
                                }
#endif
                                soisconnected(stcb->sctp_socket);
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                                SCTP_SOCKET_UNLOCK(so, 1);
#endif
                        }
                        if (SCTP_GET_STATE(asoc) == SCTP_STATE_COOKIE_ECHOED)
                                SCTP_STAT_INCR_COUNTER32(sctps_activeestab);
                        else
                                SCTP_STAT_INCR_COUNTER32(sctps_collisionestab);
                        SCTP_STAT_INCR_GAUGE32(sctps_currestab);
                } else if (SCTP_GET_STATE(asoc) == SCTP_STATE_OPEN) {
                        SCTP_STAT_INCR_COUNTER32(sctps_restartestab);
                } else {
                        SCTP_STAT_INCR_COUNTER32(sctps_collisionestab);
                }
                SCTP_SET_STATE(asoc, SCTP_STATE_OPEN);
                if (asoc->state & SCTP_STATE_SHUTDOWN_PENDING) {
                        sctp_timer_start(SCTP_TIMER_TYPE_SHUTDOWNGUARD,
                            stcb->sctp_ep, stcb, asoc->primary_destination);
                }
                sctp_stop_all_cookie_timers(stcb);
                sctp_toss_old_cookies(stcb, asoc);
                sctp_send_cookie_ack(stcb);
                if (spec_flag) {
                        /*
                         * only if we have retrans set do we do this. What
                         * this call does is get only the COOKIE-ACK out and
                         * then when we return the normal call to
                         * sctp_chunk_output will get the retrans out behind
                         * this.
                         */
                        sctp_chunk_output(inp, stcb, SCTP_OUTPUT_FROM_COOKIE_ACK, SCTP_SO_NOT_LOCKED);
                }
                if (how_indx < sizeof(asoc->cookie_how))
                        asoc->cookie_how[how_indx] = 11;

                return (stcb);
        }
        if ((ntohl(initack_cp->init.initiate_tag) != asoc->my_vtag &&
            ntohl(init_cp->init.initiate_tag) != asoc->peer_vtag) &&
            cookie->tie_tag_my_vtag == asoc->my_vtag_nonce &&
            cookie->tie_tag_peer_vtag == asoc->peer_vtag_nonce &&
            cookie->tie_tag_peer_vtag != 0) {
                struct sctpasochead *head;

#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                struct socket *so;

#endif

                if (asoc->peer_supports_nat) {
                        /*
                         * This is a gross gross hack. Just call the
                         * cookie_new code since we are allowing a duplicate
                         * association. I hope this works...
                         */
                        return (sctp_process_cookie_new(m, iphlen, offset, src, dst,
                            sh, cookie, cookie_len,
                            inp, netp, init_src, notification,
                            auth_skipped, auth_offset, auth_len,
                            mflowtype, mflowid,
                            vrf_id, port));
                }
                /*
                 * case A in Section 5.2.4 Table 2: XXMM (peer restarted)
                 */
                /* temp code */
                if (how_indx < sizeof(asoc->cookie_how))
                        asoc->cookie_how[how_indx] = 12;
                sctp_timer_stop(SCTP_TIMER_TYPE_INIT, inp, stcb, net,
                    SCTP_FROM_SCTP_INPUT + SCTP_LOC_16);
                sctp_timer_stop(SCTP_TIMER_TYPE_HEARTBEAT, inp, stcb, net,
                    SCTP_FROM_SCTP_INPUT + SCTP_LOC_17);

                /* notify upper layer */
                *notification = SCTP_NOTIFY_ASSOC_RESTART;
                atomic_add_int(&stcb->asoc.refcnt, 1);
                if ((SCTP_GET_STATE(asoc) != SCTP_STATE_OPEN) &&
                    (SCTP_GET_STATE(asoc) != SCTP_STATE_SHUTDOWN_RECEIVED) &&
                    (SCTP_GET_STATE(asoc) != SCTP_STATE_SHUTDOWN_SENT)) {
                        SCTP_STAT_INCR_GAUGE32(sctps_currestab);
                }
                if (SCTP_GET_STATE(asoc) == SCTP_STATE_OPEN) {
                        SCTP_STAT_INCR_GAUGE32(sctps_restartestab);
                } else if (SCTP_GET_STATE(asoc) != SCTP_STATE_SHUTDOWN_SENT) {
                        SCTP_STAT_INCR_GAUGE32(sctps_collisionestab);
                }
                if (asoc->state & SCTP_STATE_SHUTDOWN_PENDING) {
                        SCTP_SET_STATE(asoc, SCTP_STATE_OPEN);
                        sctp_timer_start(SCTP_TIMER_TYPE_SHUTDOWNGUARD,
                            stcb->sctp_ep, stcb, asoc->primary_destination);

                } else if (!(asoc->state & SCTP_STATE_SHUTDOWN_SENT)) {
                        /* move to OPEN state, if not in SHUTDOWN_SENT */
                        SCTP_SET_STATE(asoc, SCTP_STATE_OPEN);
                }
                asoc->pre_open_streams =
                    ntohs(initack_cp->init.num_outbound_streams);
                asoc->init_seq_number = ntohl(initack_cp->init.initial_tsn);
                asoc->sending_seq = asoc->asconf_seq_out = asoc->str_reset_seq_out = asoc->init_seq_number;
                asoc->asconf_seq_out_acked = asoc->asconf_seq_out - 1;

                asoc->asconf_seq_in = asoc->last_acked_seq = asoc->init_seq_number - 1;

                asoc->str_reset_seq_in = asoc->init_seq_number;

                asoc->advanced_peer_ack_point = asoc->last_acked_seq;
                if (asoc->mapping_array) {
                        memset(asoc->mapping_array, 0,
                            asoc->mapping_array_size);
                }
                if (asoc->nr_mapping_array) {
                        memset(asoc->nr_mapping_array, 0,
                            asoc->mapping_array_size);
                }
                SCTP_TCB_UNLOCK(stcb);
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                so = SCTP_INP_SO(stcb->sctp_ep);
                SCTP_SOCKET_LOCK(so, 1);
#endif
                SCTP_INP_INFO_WLOCK();
                SCTP_INP_WLOCK(stcb->sctp_ep);
                SCTP_TCB_LOCK(stcb);
                atomic_add_int(&stcb->asoc.refcnt, -1);
                /* send up all the data */
                SCTP_TCB_SEND_LOCK(stcb);

                sctp_report_all_outbound(stcb, 0, 1, SCTP_SO_LOCKED);
                for (i = 0; i < stcb->asoc.streamoutcnt; i++) {
                        stcb->asoc.strmout[i].chunks_on_queues = 0;
#if defined(SCTP_DETAILED_STR_STATS)
                        for (j = 0; j < SCTP_PR_SCTP_MAX + 1; j++) {
                                asoc->strmout[i].abandoned_sent[j] = 0;
                                asoc->strmout[i].abandoned_unsent[j] = 0;
                        }
#else
                        asoc->strmout[i].abandoned_sent[0] = 0;
                        asoc->strmout[i].abandoned_unsent[0] = 0;
#endif
                        stcb->asoc.strmout[i].stream_no = i;
                        stcb->asoc.strmout[i].next_sequence_send = 0;
                        stcb->asoc.strmout[i].last_msg_incomplete = 0;
                }
                /* process the INIT-ACK info (my info) */
                asoc->my_vtag = ntohl(initack_cp->init.initiate_tag);
                asoc->my_rwnd = ntohl(initack_cp->init.a_rwnd);

                /* pull from vtag hash */
                LIST_REMOVE(stcb, sctp_asocs);
                /* re-insert to new vtag position */
                head = &SCTP_BASE_INFO(sctp_asochash)[SCTP_PCBHASH_ASOC(stcb->asoc.my_vtag,
                    SCTP_BASE_INFO(hashasocmark))];
                /*
                 * put it in the bucket in the vtag hash of assoc's for the
                 * system
                 */
                LIST_INSERT_HEAD(head, stcb, sctp_asocs);

                SCTP_TCB_SEND_UNLOCK(stcb);
                SCTP_INP_WUNLOCK(stcb->sctp_ep);
                SCTP_INP_INFO_WUNLOCK();
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                SCTP_SOCKET_UNLOCK(so, 1);
#endif
                asoc->total_flight = 0;
                asoc->total_flight_count = 0;
                /* process the INIT info (peer's info) */
                retval = sctp_process_init(init_cp, stcb);
                if (retval < 0) {
                        if (how_indx < sizeof(asoc->cookie_how))
                                asoc->cookie_how[how_indx] = 13;

                        return (NULL);
                }
                /*
                 * since we did not send a HB make sure we don't double
                 * things
                 */
                net->hb_responded = 1;

                if (sctp_load_addresses_from_init(stcb, m,
                    init_offset + sizeof(struct sctp_init_chunk),
                    initack_offset, src, dst, init_src)) {
                        if (how_indx < sizeof(asoc->cookie_how))
                                asoc->cookie_how[how_indx] = 14;

                        return (NULL);
                }
                /* respond with a COOKIE-ACK */
                sctp_stop_all_cookie_timers(stcb);
                sctp_toss_old_cookies(stcb, asoc);
                sctp_send_cookie_ack(stcb);
                if (how_indx < sizeof(asoc->cookie_how))
                        asoc->cookie_how[how_indx] = 15;

                return (stcb);
        }
        if (how_indx < sizeof(asoc->cookie_how))
                asoc->cookie_how[how_indx] = 16;
        /* all other cases... */
        return (NULL);
}


/*
 * handle a state cookie for a new association m: input packet mbuf chain--
 * assumes a pullup on IP/SCTP/COOKIE-ECHO chunk note: this is a "split" mbuf
 * and the cookie signature does not exist offset: offset into mbuf to the
 * cookie-echo chunk length: length of the cookie chunk to: where the init
 * was from returns a new TCB
 */
static struct sctp_tcb *
sctp_process_cookie_new(struct mbuf *m, int iphlen, int offset,
    struct sockaddr *src, struct sockaddr *dst,
    struct sctphdr *sh, struct sctp_state_cookie *cookie, int cookie_len,
    struct sctp_inpcb *inp, struct sctp_nets **netp,
    struct sockaddr *init_src, int *notification,
    int auth_skipped, uint32_t auth_offset, uint32_t auth_len,
    uint8_t mflowtype, uint32_t mflowid,
    uint32_t vrf_id, uint16_t port)
{
        struct sctp_tcb *stcb;
        struct sctp_init_chunk *init_cp, init_buf;
        struct sctp_init_ack_chunk *initack_cp, initack_buf;
        union sctp_sockstore store;
        struct sctp_association *asoc;
        int init_offset, initack_offset, initack_limit;
        int retval;
        int error = 0;
        uint8_t auth_chunk_buf[SCTP_PARAM_BUFFER_SIZE];

#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
        struct socket *so;

        so = SCTP_INP_SO(inp);
#endif

        /*
         * find and validate the INIT chunk in the cookie (peer's info) the
         * INIT should start after the cookie-echo header struct (chunk
         * header, state cookie header struct)
         */
        init_offset = offset + sizeof(struct sctp_cookie_echo_chunk);
        init_cp = (struct sctp_init_chunk *)
            sctp_m_getptr(m, init_offset, sizeof(struct sctp_init_chunk),
            (uint8_t *) & init_buf);
        if (init_cp == NULL) {
                /* could not pull a INIT chunk in cookie */
                SCTPDBG(SCTP_DEBUG_INPUT1,
                    "process_cookie_new: could not pull INIT chunk hdr\n");
                return (NULL);
        }
        if (init_cp->ch.chunk_type != SCTP_INITIATION) {
                SCTPDBG(SCTP_DEBUG_INPUT1, "HUH? process_cookie_new: could not find INIT chunk!\n");
                return (NULL);
        }
        initack_offset = init_offset + SCTP_SIZE32(ntohs(init_cp->ch.chunk_length));
        /*
         * find and validate the INIT-ACK chunk in the cookie (my info) the
         * INIT-ACK follows the INIT chunk
         */
        initack_cp = (struct sctp_init_ack_chunk *)
            sctp_m_getptr(m, initack_offset, sizeof(struct sctp_init_ack_chunk),
            (uint8_t *) & initack_buf);
        if (initack_cp == NULL) {
                /* could not pull INIT-ACK chunk in cookie */
                SCTPDBG(SCTP_DEBUG_INPUT1, "process_cookie_new: could not pull INIT-ACK chunk hdr\n");
                return (NULL);
        }
        if (initack_cp->ch.chunk_type != SCTP_INITIATION_ACK) {
                return (NULL);
        }
        /*
         * NOTE: We can't use the INIT_ACK's chk_length to determine the
         * "initack_limit" value.  This is because the chk_length field
         * includes the length of the cookie, but the cookie is omitted when
         * the INIT and INIT_ACK are tacked onto the cookie...
         */
        initack_limit = offset + cookie_len;

        /*
         * now that we know the INIT/INIT-ACK are in place, create a new TCB
         * and popluate
         */

        /*
         * Here we do a trick, we set in NULL for the proc/thread argument.
         * We do this since in effect we only use the p argument when the
         * socket is unbound and we must do an implicit bind. Since we are
         * getting a cookie, we cannot be unbound.
         */
        stcb = sctp_aloc_assoc(inp, init_src, &error,
            ntohl(initack_cp->init.initiate_tag), vrf_id,
            ntohs(initack_cp->init.num_outbound_streams),
            (struct thread *)NULL
            );
        if (stcb == NULL) {
                struct mbuf *op_err;

                /* memory problem? */
                SCTPDBG(SCTP_DEBUG_INPUT1,
                    "process_cookie_new: no room for another TCB!\n");
                op_err = sctp_generate_cause(SCTP_CAUSE_OUT_OF_RESC, "");
                sctp_abort_association(inp, (struct sctp_tcb *)NULL, m, iphlen,
                    src, dst, sh, op_err,
                    mflowtype, mflowid,
                    vrf_id, port);
                return (NULL);
        }
        /* get the correct sctp_nets */
        if (netp)
                *netp = sctp_findnet(stcb, init_src);

        asoc = &stcb->asoc;
        /* get scope variables out of cookie */
        asoc->scope.ipv4_local_scope = cookie->ipv4_scope;
        asoc->scope.site_scope = cookie->site_scope;
        asoc->scope.local_scope = cookie->local_scope;
        asoc->scope.loopback_scope = cookie->loopback_scope;

        if ((asoc->scope.ipv4_addr_legal != cookie->ipv4_addr_legal) ||
            (asoc->scope.ipv6_addr_legal != cookie->ipv6_addr_legal)) {
                struct mbuf *op_err;

                /*
                 * Houston we have a problem. The EP changed while the
                 * cookie was in flight. Only recourse is to abort the
                 * association.
                 */
                atomic_add_int(&stcb->asoc.refcnt, 1);
                op_err = sctp_generate_cause(SCTP_CAUSE_OUT_OF_RESC, "");
                sctp_abort_association(inp, (struct sctp_tcb *)NULL, m, iphlen,
                    src, dst, sh, op_err,
                    mflowtype, mflowid,
                    vrf_id, port);
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                SCTP_TCB_UNLOCK(stcb);
                SCTP_SOCKET_LOCK(so, 1);
                SCTP_TCB_LOCK(stcb);
#endif
                (void)sctp_free_assoc(inp, stcb, SCTP_NORMAL_PROC,
                    SCTP_FROM_SCTP_INPUT + SCTP_LOC_18);
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                SCTP_SOCKET_UNLOCK(so, 1);
#endif
                atomic_subtract_int(&stcb->asoc.refcnt, 1);
                return (NULL);
        }
        /* process the INIT-ACK info (my info) */
        asoc->my_vtag = ntohl(initack_cp->init.initiate_tag);
        asoc->my_rwnd = ntohl(initack_cp->init.a_rwnd);
        asoc->pre_open_streams = ntohs(initack_cp->init.num_outbound_streams);
        asoc->init_seq_number = ntohl(initack_cp->init.initial_tsn);
        asoc->sending_seq = asoc->asconf_seq_out = asoc->str_reset_seq_out = asoc->init_seq_number;
        asoc->asconf_seq_out_acked = asoc->asconf_seq_out - 1;
        asoc->asconf_seq_in = asoc->last_acked_seq = asoc->init_seq_number - 1;
        asoc->str_reset_seq_in = asoc->init_seq_number;

        asoc->advanced_peer_ack_point = asoc->last_acked_seq;

        /* process the INIT info (peer's info) */
        if (netp)
                retval = sctp_process_init(init_cp, stcb);
        else
                retval = 0;
        if (retval < 0) {
                atomic_add_int(&stcb->asoc.refcnt, 1);
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                SCTP_TCB_UNLOCK(stcb);
                SCTP_SOCKET_LOCK(so, 1);
                SCTP_TCB_LOCK(stcb);
#endif
                (void)sctp_free_assoc(inp, stcb, SCTP_NORMAL_PROC,
                    SCTP_FROM_SCTP_INPUT + SCTP_LOC_19);
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                SCTP_SOCKET_UNLOCK(so, 1);
#endif
                atomic_subtract_int(&stcb->asoc.refcnt, 1);
                return (NULL);
        }
        /* load all addresses */
        if (sctp_load_addresses_from_init(stcb, m,
            init_offset + sizeof(struct sctp_init_chunk), initack_offset,
            src, dst, init_src)) {
                atomic_add_int(&stcb->asoc.refcnt, 1);
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                SCTP_TCB_UNLOCK(stcb);
                SCTP_SOCKET_LOCK(so, 1);
                SCTP_TCB_LOCK(stcb);
#endif
                (void)sctp_free_assoc(inp, stcb, SCTP_NORMAL_PROC,
                    SCTP_FROM_SCTP_INPUT + SCTP_LOC_20);
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                SCTP_SOCKET_UNLOCK(so, 1);
#endif
                atomic_subtract_int(&stcb->asoc.refcnt, 1);
                return (NULL);
        }
        /*
         * verify any preceding AUTH chunk that was skipped
         */
        /* pull the local authentication parameters from the cookie/init-ack */
        sctp_auth_get_cookie_params(stcb, m,
            initack_offset + sizeof(struct sctp_init_ack_chunk),
            initack_limit - (initack_offset + sizeof(struct sctp_init_ack_chunk)));
        if (auth_skipped) {
                struct sctp_auth_chunk *auth;

                auth = (struct sctp_auth_chunk *)
                    sctp_m_getptr(m, auth_offset, auth_len, auth_chunk_buf);
                if ((auth == NULL) || sctp_handle_auth(stcb, auth, m, auth_offset)) {
                        /* auth HMAC failed, dump the assoc and packet */
                        SCTPDBG(SCTP_DEBUG_AUTH1,
                            "COOKIE-ECHO: AUTH failed\n");
                        atomic_add_int(&stcb->asoc.refcnt, 1);
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                        SCTP_TCB_UNLOCK(stcb);
                        SCTP_SOCKET_LOCK(so, 1);
                        SCTP_TCB_LOCK(stcb);
#endif
                        (void)sctp_free_assoc(inp, stcb, SCTP_NORMAL_PROC,
                            SCTP_FROM_SCTP_INPUT + SCTP_LOC_21);
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                        SCTP_SOCKET_UNLOCK(so, 1);
#endif
                        atomic_subtract_int(&stcb->asoc.refcnt, 1);
                        return (NULL);
                } else {
                        /* remaining chunks checked... good to go */
                        stcb->asoc.authenticated = 1;
                }
        }
        /* update current state */
        SCTPDBG(SCTP_DEBUG_INPUT2, "moving to OPEN state\n");
        SCTP_SET_STATE(asoc, SCTP_STATE_OPEN);
        if (asoc->state & SCTP_STATE_SHUTDOWN_PENDING) {
                sctp_timer_start(SCTP_TIMER_TYPE_SHUTDOWNGUARD,
                    stcb->sctp_ep, stcb, asoc->primary_destination);
        }
        sctp_stop_all_cookie_timers(stcb);
        SCTP_STAT_INCR_COUNTER32(sctps_passiveestab);
        SCTP_STAT_INCR_GAUGE32(sctps_currestab);

        /*
         * if we're doing ASCONFs, check to see if we have any new local
         * addresses that need to get added to the peer (eg. addresses
         * changed while cookie echo in flight).  This needs to be done
         * after we go to the OPEN state to do the correct asconf
         * processing. else, make sure we have the correct addresses in our
         * lists
         */

        /* warning, we re-use sin, sin6, sa_store here! */
        /* pull in local_address (our "from" address) */
        switch (cookie->laddr_type) {
#ifdef INET
        case SCTP_IPV4_ADDRESS:
                /* source addr is IPv4 */
                memset(&store.sin, 0, sizeof(struct sockaddr_in));
                store.sin.sin_family = AF_INET;
                store.sin.sin_len = sizeof(struct sockaddr_in);
                store.sin.sin_addr.s_addr = cookie->laddress[0];
                break;
#endif
#ifdef INET6
        case SCTP_IPV6_ADDRESS:
                /* source addr is IPv6 */
                memset(&store.sin6, 0, sizeof(struct sockaddr_in6));
                store.sin6.sin6_family = AF_INET6;
                store.sin6.sin6_len = sizeof(struct sockaddr_in6);
                store.sin6.sin6_scope_id = cookie->scope_id;
                memcpy(&store.sin6.sin6_addr, cookie->laddress, sizeof(struct in6_addr));
                break;
#endif
        default:
                atomic_add_int(&stcb->asoc.refcnt, 1);
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                SCTP_TCB_UNLOCK(stcb);
                SCTP_SOCKET_LOCK(so, 1);
                SCTP_TCB_LOCK(stcb);
#endif
                (void)sctp_free_assoc(inp, stcb, SCTP_NORMAL_PROC,
                    SCTP_FROM_SCTP_INPUT + SCTP_LOC_22);
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                SCTP_SOCKET_UNLOCK(so, 1);
#endif
                atomic_subtract_int(&stcb->asoc.refcnt, 1);
                return (NULL);
        }

        /* set up to notify upper layer */
        *notification = SCTP_NOTIFY_ASSOC_UP;
        if (((stcb->sctp_ep->sctp_flags & SCTP_PCB_FLAGS_TCPTYPE) ||
            (stcb->sctp_ep->sctp_flags & SCTP_PCB_FLAGS_IN_TCPPOOL)) &&
            (inp->sctp_socket->so_qlimit == 0)) {
                /*
                 * This is an endpoint that called connect() how it got a
                 * cookie that is NEW is a bit of a mystery. It must be that
                 * the INIT was sent, but before it got there.. a complete
                 * INIT/INIT-ACK/COOKIE arrived. But of course then it
                 * should have went to the other code.. not here.. oh well..
                 * a bit of protection is worth having..
                 */
                stcb->sctp_ep->sctp_flags |= SCTP_PCB_FLAGS_CONNECTED;
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                atomic_add_int(&stcb->asoc.refcnt, 1);
                SCTP_TCB_UNLOCK(stcb);
                SCTP_SOCKET_LOCK(so, 1);
                SCTP_TCB_LOCK(stcb);
                atomic_subtract_int(&stcb->asoc.refcnt, 1);
                if (stcb->asoc.state & SCTP_STATE_CLOSED_SOCKET) {
                        SCTP_SOCKET_UNLOCK(so, 1);
                        return (NULL);
                }
#endif
                soisconnected(stcb->sctp_socket);
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                SCTP_SOCKET_UNLOCK(so, 1);
#endif
        } else if ((stcb->sctp_ep->sctp_flags & SCTP_PCB_FLAGS_TCPTYPE) &&
            (inp->sctp_socket->so_qlimit)) {
                /*
                 * We don't want to do anything with this one. Since it is
                 * the listening guy. The timer will get started for
                 * accepted connections in the caller.
                 */
                ;
        }
        /* since we did not send a HB make sure we don't double things */
        if ((netp) && (*netp))
                (*netp)->hb_responded = 1;

        if (stcb->asoc.sctp_autoclose_ticks &&
            sctp_is_feature_on(inp, SCTP_PCB_FLAGS_AUTOCLOSE)) {
                sctp_timer_start(SCTP_TIMER_TYPE_AUTOCLOSE, inp, stcb, NULL);
        }
        (void)SCTP_GETTIME_TIMEVAL(&stcb->asoc.time_entered);
        if ((netp != NULL) && (*netp != NULL)) {
                /* calculate the RTT and set the encaps port */
                (*netp)->RTO = sctp_calculate_rto(stcb, asoc, *netp,
                    &cookie->time_entered, sctp_align_unsafe_makecopy,
                    SCTP_RTT_FROM_NON_DATA);
#if defined(INET) || defined(INET6)
                if (((*netp)->port == 0) && (port != 0)) {
                        sctp_pathmtu_adjustment(stcb, (*netp)->mtu - sizeof(struct udphdr));
                }
                (*netp)->port = port;
#endif
        }
        /* respond with a COOKIE-ACK */
        sctp_send_cookie_ack(stcb);

        /*
         * check the address lists for any ASCONFs that need to be sent
         * AFTER the cookie-ack is sent
         */
        sctp_check_address_list(stcb, m,
            initack_offset + sizeof(struct sctp_init_ack_chunk),
            initack_limit - (initack_offset + sizeof(struct sctp_init_ack_chunk)),
            &store.sa, cookie->local_scope, cookie->site_scope,
            cookie->ipv4_scope, cookie->loopback_scope);


        return (stcb);
}

/*
 * CODE LIKE THIS NEEDS TO RUN IF the peer supports the NAT extension, i.e
 * we NEED to make sure we are not already using the vtag. If so we
 * need to send back an ABORT-TRY-AGAIN-WITH-NEW-TAG No middle box bit!
        head = &SCTP_BASE_INFO(sctp_asochash)[SCTP_PCBHASH_ASOC(tag,
                                                            SCTP_BASE_INFO(hashasocmark))];
        LIST_FOREACH(stcb, head, sctp_asocs) {
                if ((stcb->asoc.my_vtag == tag) && (stcb->rport == rport) && (inp == stcb->sctp_ep))  {
                       -- SEND ABORT - TRY AGAIN --
                }
        }
*/

/*
 * handles a COOKIE-ECHO message stcb: modified to either a new or left as
 * existing (non-NULL) TCB
 */
static struct mbuf *
sctp_handle_cookie_echo(struct mbuf *m, int iphlen, int offset,
    struct sockaddr *src, struct sockaddr *dst,
    struct sctphdr *sh, struct sctp_cookie_echo_chunk *cp,
    struct sctp_inpcb **inp_p, struct sctp_tcb **stcb, struct sctp_nets **netp,
    int auth_skipped, uint32_t auth_offset, uint32_t auth_len,
    struct sctp_tcb **locked_tcb,
    uint8_t mflowtype, uint32_t mflowid,
    uint32_t vrf_id, uint16_t port)
{
        struct sctp_state_cookie *cookie;
        struct sctp_tcb *l_stcb = *stcb;
        struct sctp_inpcb *l_inp;
        struct sockaddr *to;
        struct sctp_pcb *ep;
        struct mbuf *m_sig;
        uint8_t calc_sig[SCTP_SIGNATURE_SIZE], tmp_sig[SCTP_SIGNATURE_SIZE];
        uint8_t *sig;
        uint8_t cookie_ok = 0;
        unsigned int sig_offset, cookie_offset;
        unsigned int cookie_len;
        struct timeval now;
        struct timeval time_expires;
        int notification = 0;
        struct sctp_nets *netl;
        int had_a_existing_tcb = 0;
        int send_int_conf = 0;

#ifdef INET
        struct sockaddr_in sin;

#endif
#ifdef INET6
        struct sockaddr_in6 sin6;

#endif

        SCTPDBG(SCTP_DEBUG_INPUT2,
            "sctp_handle_cookie: handling COOKIE-ECHO\n");

        if (inp_p == NULL) {
                return (NULL);
        }
        cookie = &cp->cookie;
        cookie_offset = offset + sizeof(struct sctp_chunkhdr);
        cookie_len = ntohs(cp->ch.chunk_length);

        if ((cookie->peerport != sh->src_port) ||
            (cookie->myport != sh->dest_port) ||
            (cookie->my_vtag != sh->v_tag)) {
                /*
                 * invalid ports or bad tag.  Note that we always leave the
                 * v_tag in the header in network order and when we stored
                 * it in the my_vtag slot we also left it in network order.
                 * This maintains the match even though it may be in the
                 * opposite byte order of the machine :->
                 */
                return (NULL);
        }
        if (cookie_len < sizeof(struct sctp_cookie_echo_chunk) +
            sizeof(struct sctp_init_chunk) +
            sizeof(struct sctp_init_ack_chunk) + SCTP_SIGNATURE_SIZE) {
                /* cookie too small */
                return (NULL);
        }
        /*
         * split off the signature into its own mbuf (since it should not be
         * calculated in the sctp_hmac_m() call).
         */
        sig_offset = offset + cookie_len - SCTP_SIGNATURE_SIZE;
        m_sig = m_split(m, sig_offset, M_NOWAIT);
        if (m_sig == NULL) {
                /* out of memory or ?? */
                return (NULL);
        }
#ifdef SCTP_MBUF_LOGGING
        if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_MBUF_LOGGING_ENABLE) {
                sctp_log_mbc(m_sig, SCTP_MBUF_SPLIT);
        }
#endif

        /*
         * compute the signature/digest for the cookie
         */
        ep = &(*inp_p)->sctp_ep;
        l_inp = *inp_p;
        if (l_stcb) {
                SCTP_TCB_UNLOCK(l_stcb);
        }
        SCTP_INP_RLOCK(l_inp);
        if (l_stcb) {
                SCTP_TCB_LOCK(l_stcb);
        }
        /* which cookie is it? */
        if ((cookie->time_entered.tv_sec < (long)ep->time_of_secret_change) &&
            (ep->current_secret_number != ep->last_secret_number)) {
                /* it's the old cookie */
                (void)sctp_hmac_m(SCTP_HMAC,
                    (uint8_t *) ep->secret_key[(int)ep->last_secret_number],
                    SCTP_SECRET_SIZE, m, cookie_offset, calc_sig, 0);
        } else {
                /* it's the current cookie */
                (void)sctp_hmac_m(SCTP_HMAC,
                    (uint8_t *) ep->secret_key[(int)ep->current_secret_number],
                    SCTP_SECRET_SIZE, m, cookie_offset, calc_sig, 0);
        }
        /* get the signature */
        SCTP_INP_RUNLOCK(l_inp);
        sig = (uint8_t *) sctp_m_getptr(m_sig, 0, SCTP_SIGNATURE_SIZE, (uint8_t *) & tmp_sig);
        if (sig == NULL) {
                /* couldn't find signature */
                sctp_m_freem(m_sig);
                return (NULL);
        }
        /* compare the received digest with the computed digest */
        if (memcmp(calc_sig, sig, SCTP_SIGNATURE_SIZE) != 0) {
                /* try the old cookie? */
                if ((cookie->time_entered.tv_sec == (long)ep->time_of_secret_change) &&
                    (ep->current_secret_number != ep->last_secret_number)) {
                        /* compute digest with old */
                        (void)sctp_hmac_m(SCTP_HMAC,
                            (uint8_t *) ep->secret_key[(int)ep->last_secret_number],
                            SCTP_SECRET_SIZE, m, cookie_offset, calc_sig, 0);
                        /* compare */
                        if (memcmp(calc_sig, sig, SCTP_SIGNATURE_SIZE) == 0)
                                cookie_ok = 1;
                }
        } else {
                cookie_ok = 1;
        }

        /*
         * Now before we continue we must reconstruct our mbuf so that
         * normal processing of any other chunks will work.
         */
        {
                struct mbuf *m_at;

                m_at = m;
                while (SCTP_BUF_NEXT(m_at) != NULL) {
                        m_at = SCTP_BUF_NEXT(m_at);
                }
                SCTP_BUF_NEXT(m_at) = m_sig;
        }

        if (cookie_ok == 0) {
                SCTPDBG(SCTP_DEBUG_INPUT2, "handle_cookie_echo: cookie signature validation failed!\n");
                SCTPDBG(SCTP_DEBUG_INPUT2,
                    "offset = %u, cookie_offset = %u, sig_offset = %u\n",
                    (uint32_t) offset, cookie_offset, sig_offset);
                return (NULL);
        }
        /*
         * check the cookie timestamps to be sure it's not stale
         */
        (void)SCTP_GETTIME_TIMEVAL(&now);
        /* Expire time is in Ticks, so we convert to seconds */
        time_expires.tv_sec = cookie->time_entered.tv_sec + TICKS_TO_SEC(cookie->cookie_life);
        time_expires.tv_usec = cookie->time_entered.tv_usec;
        /*
         * TODO sctp_constants.h needs alternative time macros when _KERNEL
         * is undefined.
         */
        if (timevalcmp(&now, &time_expires, >)) {
                /* cookie is stale! */
                struct mbuf *op_err;
                struct sctp_error_stale_cookie *cause;
                uint32_t tim;

                op_err = sctp_get_mbuf_for_msg(sizeof(struct sctp_error_stale_cookie),
                    0, M_NOWAIT, 1, MT_DATA);
                if (op_err == NULL) {
                        /* FOOBAR */
                        return (NULL);
                }
                /* Set the len */
                SCTP_BUF_LEN(op_err) = sizeof(struct sctp_error_stale_cookie);
                cause = mtod(op_err, struct sctp_error_stale_cookie *);
                cause->cause.code = htons(SCTP_CAUSE_STALE_COOKIE);
                cause->cause.length = htons((sizeof(struct sctp_paramhdr) +
                    (sizeof(uint32_t))));
                /* seconds to usec */
                tim = (now.tv_sec - time_expires.tv_sec) * 1000000;
                /* add in usec */
                if (tim == 0)
                        tim = now.tv_usec - cookie->time_entered.tv_usec;
                cause->stale_time = htonl(tim);
                sctp_send_operr_to(src, dst, sh, cookie->peers_vtag, op_err,
                    mflowtype, mflowid, l_inp->fibnum,
                    vrf_id, port);
                return (NULL);
        }
        /*
         * Now we must see with the lookup address if we have an existing
         * asoc. This will only happen if we were in the COOKIE-WAIT state
         * and a INIT collided with us and somewhere the peer sent the
         * cookie on another address besides the single address our assoc
         * had for him. In this case we will have one of the tie-tags set at
         * least AND the address field in the cookie can be used to look it
         * up.
         */
        to = NULL;
        switch (cookie->addr_type) {
#ifdef INET6
        case SCTP_IPV6_ADDRESS:
                memset(&sin6, 0, sizeof(sin6));
                sin6.sin6_family = AF_INET6;
                sin6.sin6_len = sizeof(sin6);
                sin6.sin6_port = sh->src_port;
                sin6.sin6_scope_id = cookie->scope_id;
                memcpy(&sin6.sin6_addr.s6_addr, cookie->address,
                    sizeof(sin6.sin6_addr.s6_addr));
                to = (struct sockaddr *)&sin6;
                break;
#endif
#ifdef INET
        case SCTP_IPV4_ADDRESS:
                memset(&sin, 0, sizeof(sin));
                sin.sin_family = AF_INET;
                sin.sin_len = sizeof(sin);
                sin.sin_port = sh->src_port;
                sin.sin_addr.s_addr = cookie->address[0];
                to = (struct sockaddr *)&sin;
                break;
#endif
        default:
                /* This should not happen */
                return (NULL);
        }
        if (*stcb == NULL) {
                /* Yep, lets check */
                *stcb = sctp_findassociation_ep_addr(inp_p, to, netp, dst, NULL);
                if (*stcb == NULL) {
                        /*
                         * We should have only got back the same inp. If we
                         * got back a different ep we have a problem. The
                         * original findep got back l_inp and now
                         */
                        if (l_inp != *inp_p) {
                                SCTP_PRINTF("Bad problem find_ep got a diff inp then special_locate?\n");
                        }
                } else {
                        if (*locked_tcb == NULL) {
                                /*
                                 * In this case we found the assoc only
                                 * after we locked the create lock. This
                                 * means we are in a colliding case and we
                                 * must make sure that we unlock the tcb if
                                 * its one of the cases where we throw away
                                 * the incoming packets.
                                 */
                                *locked_tcb = *stcb;

                                /*
                                 * We must also increment the inp ref count
                                 * since the ref_count flags was set when we
                                 * did not find the TCB, now we found it
                                 * which reduces the refcount.. we must
                                 * raise it back out to balance it all :-)
                                 */
                                SCTP_INP_INCR_REF((*stcb)->sctp_ep);
                                if ((*stcb)->sctp_ep != l_inp) {
                                        SCTP_PRINTF("Huh? ep:%p diff then l_inp:%p?\n",
                                            (void *)(*stcb)->sctp_ep, (void *)l_inp);
                                }
                        }
                }
        }
        cookie_len -= SCTP_SIGNATURE_SIZE;
        if (*stcb == NULL) {
                /* this is the "normal" case... get a new TCB */
                *stcb = sctp_process_cookie_new(m, iphlen, offset, src, dst, sh,
                    cookie, cookie_len, *inp_p,
                    netp, to, &notification,
                    auth_skipped, auth_offset, auth_len,
                    mflowtype, mflowid,
                    vrf_id, port);
        } else {
                /* this is abnormal... cookie-echo on existing TCB */
                had_a_existing_tcb = 1;
                *stcb = sctp_process_cookie_existing(m, iphlen, offset,
                    src, dst, sh,
                    cookie, cookie_len, *inp_p, *stcb, netp, to,
                    &notification, auth_skipped, auth_offset, auth_len,
                    mflowtype, mflowid,
                    vrf_id, port);
        }

        if (*stcb == NULL) {
                /* still no TCB... must be bad cookie-echo */
                return (NULL);
        }
        if (*netp != NULL) {
                (*netp)->flowtype = mflowtype;
                (*netp)->flowid = mflowid;
        }
        /*
         * Ok, we built an association so confirm the address we sent the
         * INIT-ACK to.
         */
        netl = sctp_findnet(*stcb, to);
        /*
         * This code should in theory NOT run but
         */
        if (netl == NULL) {
                /* TSNH! Huh, why do I need to add this address here? */
                if (sctp_add_remote_addr(*stcb, to, NULL, SCTP_DONOT_SETSCOPE, SCTP_IN_COOKIE_PROC)) {
                        return (NULL);
                }
                netl = sctp_findnet(*stcb, to);
        }
        if (netl) {
                if (netl->dest_state & SCTP_ADDR_UNCONFIRMED) {
                        netl->dest_state &= ~SCTP_ADDR_UNCONFIRMED;
                        (void)sctp_set_primary_addr((*stcb), (struct sockaddr *)NULL,
                            netl);
                        send_int_conf = 1;
                }
        }
        sctp_start_net_timers(*stcb);
        if ((*inp_p)->sctp_flags & SCTP_PCB_FLAGS_TCPTYPE) {
                if (!had_a_existing_tcb ||
                    (((*inp_p)->sctp_flags & SCTP_PCB_FLAGS_CONNECTED) == 0)) {
                        /*
                         * If we have a NEW cookie or the connect never
                         * reached the connected state during collision we
                         * must do the TCP accept thing.
                         */
                        struct socket *so, *oso;
                        struct sctp_inpcb *inp;

                        if (notification == SCTP_NOTIFY_ASSOC_RESTART) {
                                /*
                                 * For a restart we will keep the same
                                 * socket, no need to do anything. I THINK!!
                                 */
                                sctp_ulp_notify(notification, *stcb, 0, NULL, SCTP_SO_NOT_LOCKED);
                                if (send_int_conf) {
                                        sctp_ulp_notify(SCTP_NOTIFY_INTERFACE_CONFIRMED,
                                            (*stcb), 0, (void *)netl, SCTP_SO_NOT_LOCKED);
                                }
                                return (m);
                        }
                        oso = (*inp_p)->sctp_socket;
                        atomic_add_int(&(*stcb)->asoc.refcnt, 1);
                        SCTP_TCB_UNLOCK((*stcb));
                        CURVNET_SET(oso->so_vnet);
                        so = sonewconn(oso, 0
                            );
                        CURVNET_RESTORE();
                        SCTP_TCB_LOCK((*stcb));
                        atomic_subtract_int(&(*stcb)->asoc.refcnt, 1);

                        if (so == NULL) {
                                struct mbuf *op_err;

#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                                struct socket *pcb_so;

#endif
                                /* Too many sockets */
                                SCTPDBG(SCTP_DEBUG_INPUT1, "process_cookie_new: no room for another socket!\n");
                                op_err = sctp_generate_cause(SCTP_CAUSE_OUT_OF_RESC, "");
                                sctp_abort_association(*inp_p, NULL, m, iphlen,
                                    src, dst, sh, op_err,
                                    mflowtype, mflowid,
                                    vrf_id, port);
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                                pcb_so = SCTP_INP_SO(*inp_p);
                                atomic_add_int(&(*stcb)->asoc.refcnt, 1);
                                SCTP_TCB_UNLOCK((*stcb));
                                SCTP_SOCKET_LOCK(pcb_so, 1);
                                SCTP_TCB_LOCK((*stcb));
                                atomic_subtract_int(&(*stcb)->asoc.refcnt, 1);
#endif
                                (void)sctp_free_assoc(*inp_p, *stcb, SCTP_NORMAL_PROC,
                                    SCTP_FROM_SCTP_INPUT + SCTP_LOC_23);
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                                SCTP_SOCKET_UNLOCK(pcb_so, 1);
#endif
                                return (NULL);
                        }
                        inp = (struct sctp_inpcb *)so->so_pcb;
                        SCTP_INP_INCR_REF(inp);
                        /*
                         * We add the unbound flag here so that if we get an
                         * soabort() before we get the move_pcb done, we
                         * will properly cleanup.
                         */
                        inp->sctp_flags = (SCTP_PCB_FLAGS_TCPTYPE |
                            SCTP_PCB_FLAGS_CONNECTED |
                            SCTP_PCB_FLAGS_IN_TCPPOOL |
                            SCTP_PCB_FLAGS_UNBOUND |
                            (SCTP_PCB_COPY_FLAGS & (*inp_p)->sctp_flags) |
                            SCTP_PCB_FLAGS_DONT_WAKE);
                        inp->sctp_features = (*inp_p)->sctp_features;
                        inp->sctp_mobility_features = (*inp_p)->sctp_mobility_features;
                        inp->sctp_socket = so;
                        inp->sctp_frag_point = (*inp_p)->sctp_frag_point;
                        inp->max_cwnd = (*inp_p)->max_cwnd;
                        inp->sctp_cmt_on_off = (*inp_p)->sctp_cmt_on_off;
                        inp->ecn_supported = (*inp_p)->ecn_supported;
                        inp->prsctp_supported = (*inp_p)->prsctp_supported;
                        inp->auth_supported = (*inp_p)->auth_supported;
                        inp->asconf_supported = (*inp_p)->asconf_supported;
                        inp->reconfig_supported = (*inp_p)->reconfig_supported;
                        inp->nrsack_supported = (*inp_p)->nrsack_supported;
                        inp->pktdrop_supported = (*inp_p)->pktdrop_supported;
                        inp->partial_delivery_point = (*inp_p)->partial_delivery_point;
                        inp->sctp_context = (*inp_p)->sctp_context;
                        inp->local_strreset_support = (*inp_p)->local_strreset_support;
                        inp->fibnum = (*inp_p)->fibnum;
                        inp->inp_starting_point_for_iterator = NULL;
                        /*
                         * copy in the authentication parameters from the
                         * original endpoint
                         */
                        if (inp->sctp_ep.local_hmacs)
                                sctp_free_hmaclist(inp->sctp_ep.local_hmacs);
                        inp->sctp_ep.local_hmacs =
                            sctp_copy_hmaclist((*inp_p)->sctp_ep.local_hmacs);
                        if (inp->sctp_ep.local_auth_chunks)
                                sctp_free_chunklist(inp->sctp_ep.local_auth_chunks);
                        inp->sctp_ep.local_auth_chunks =
                            sctp_copy_chunklist((*inp_p)->sctp_ep.local_auth_chunks);

                        /*
                         * Now we must move it from one hash table to
                         * another and get the tcb in the right place.
                         */

                        /*
                         * This is where the one-2-one socket is put into
                         * the accept state waiting for the accept!
                         */
                        if (*stcb) {
                                (*stcb)->asoc.state |= SCTP_STATE_IN_ACCEPT_QUEUE;
                        }
                        sctp_move_pcb_and_assoc(*inp_p, inp, *stcb);

                        atomic_add_int(&(*stcb)->asoc.refcnt, 1);
                        SCTP_TCB_UNLOCK((*stcb));

                        sctp_pull_off_control_to_new_inp((*inp_p), inp, *stcb,
                            0);
                        SCTP_TCB_LOCK((*stcb));
                        atomic_subtract_int(&(*stcb)->asoc.refcnt, 1);


                        /*
                         * now we must check to see if we were aborted while
                         * the move was going on and the lock/unlock
                         * happened.
                         */
                        if (inp->sctp_flags & SCTP_PCB_FLAGS_SOCKET_GONE) {
                                /*
                                 * yep it was, we leave the assoc attached
                                 * to the socket since the sctp_inpcb_free()
                                 * call will send an abort for us.
                                 */
                                SCTP_INP_DECR_REF(inp);
                                return (NULL);
                        }
                        SCTP_INP_DECR_REF(inp);
                        /* Switch over to the new guy */
                        *inp_p = inp;
                        sctp_ulp_notify(notification, *stcb, 0, NULL, SCTP_SO_NOT_LOCKED);
                        if (send_int_conf) {
                                sctp_ulp_notify(SCTP_NOTIFY_INTERFACE_CONFIRMED,
                                    (*stcb), 0, (void *)netl, SCTP_SO_NOT_LOCKED);
                        }
                        /*
                         * Pull it from the incomplete queue and wake the
                         * guy
                         */
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                        atomic_add_int(&(*stcb)->asoc.refcnt, 1);
                        SCTP_TCB_UNLOCK((*stcb));
                        SCTP_SOCKET_LOCK(so, 1);
#endif
                        soisconnected(so);
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                        SCTP_TCB_LOCK((*stcb));
                        atomic_subtract_int(&(*stcb)->asoc.refcnt, 1);
                        SCTP_SOCKET_UNLOCK(so, 1);
#endif
                        return (m);
                }
        }
        if (notification) {
                sctp_ulp_notify(notification, *stcb, 0, NULL, SCTP_SO_NOT_LOCKED);
        }
        if (send_int_conf) {
                sctp_ulp_notify(SCTP_NOTIFY_INTERFACE_CONFIRMED,
                    (*stcb), 0, (void *)netl, SCTP_SO_NOT_LOCKED);
        }
        return (m);
}

static void
sctp_handle_cookie_ack(struct sctp_cookie_ack_chunk *cp SCTP_UNUSED,
    struct sctp_tcb *stcb, struct sctp_nets *net)
{
        /* cp must not be used, others call this without a c-ack :-) */
        struct sctp_association *asoc;

        SCTPDBG(SCTP_DEBUG_INPUT2,
            "sctp_handle_cookie_ack: handling COOKIE-ACK\n");
        if ((stcb == NULL) || (net == NULL)) {
                return;
        }
        asoc = &stcb->asoc;

        sctp_stop_all_cookie_timers(stcb);
        /* process according to association state */
        if (SCTP_GET_STATE(asoc) == SCTP_STATE_COOKIE_ECHOED) {
                /* state change only needed when I am in right state */
                SCTPDBG(SCTP_DEBUG_INPUT2, "moving to OPEN state\n");
                SCTP_SET_STATE(asoc, SCTP_STATE_OPEN);
                sctp_start_net_timers(stcb);
                if (asoc->state & SCTP_STATE_SHUTDOWN_PENDING) {
                        sctp_timer_start(SCTP_TIMER_TYPE_SHUTDOWNGUARD,
                            stcb->sctp_ep, stcb, asoc->primary_destination);

                }
                /* update RTO */
                SCTP_STAT_INCR_COUNTER32(sctps_activeestab);
                SCTP_STAT_INCR_GAUGE32(sctps_currestab);
                if (asoc->overall_error_count == 0) {
                        net->RTO = sctp_calculate_rto(stcb, asoc, net,
                            &asoc->time_entered, sctp_align_safe_nocopy,
                            SCTP_RTT_FROM_NON_DATA);
                }
                (void)SCTP_GETTIME_TIMEVAL(&asoc->time_entered);
                sctp_ulp_notify(SCTP_NOTIFY_ASSOC_UP, stcb, 0, NULL, SCTP_SO_NOT_LOCKED);
                if ((stcb->sctp_ep->sctp_flags & SCTP_PCB_FLAGS_TCPTYPE) ||
                    (stcb->sctp_ep->sctp_flags & SCTP_PCB_FLAGS_IN_TCPPOOL)) {
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                        struct socket *so;

#endif
                        stcb->sctp_ep->sctp_flags |= SCTP_PCB_FLAGS_CONNECTED;
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                        so = SCTP_INP_SO(stcb->sctp_ep);
                        atomic_add_int(&stcb->asoc.refcnt, 1);
                        SCTP_TCB_UNLOCK(stcb);
                        SCTP_SOCKET_LOCK(so, 1);
                        SCTP_TCB_LOCK(stcb);
                        atomic_subtract_int(&stcb->asoc.refcnt, 1);
#endif
                        if ((stcb->asoc.state & SCTP_STATE_CLOSED_SOCKET) == 0) {
                                soisconnected(stcb->sctp_socket);
                        }
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                        SCTP_SOCKET_UNLOCK(so, 1);
#endif
                }
                /*
                 * since we did not send a HB make sure we don't double
                 * things
                 */
                net->hb_responded = 1;

                if (stcb->asoc.state & SCTP_STATE_CLOSED_SOCKET) {
                        /*
                         * We don't need to do the asconf thing, nor hb or
                         * autoclose if the socket is closed.
                         */
                        goto closed_socket;
                }
                sctp_timer_start(SCTP_TIMER_TYPE_HEARTBEAT, stcb->sctp_ep,
                    stcb, net);


                if (stcb->asoc.sctp_autoclose_ticks &&
                    sctp_is_feature_on(stcb->sctp_ep, SCTP_PCB_FLAGS_AUTOCLOSE)) {
                        sctp_timer_start(SCTP_TIMER_TYPE_AUTOCLOSE,
                            stcb->sctp_ep, stcb, NULL);
                }
                /*
                 * send ASCONF if parameters are pending and ASCONFs are
                 * allowed (eg. addresses changed when init/cookie echo were
                 * in flight)
                 */
                if ((sctp_is_feature_on(stcb->sctp_ep, SCTP_PCB_FLAGS_DO_ASCONF)) &&
                    (stcb->asoc.asconf_supported == 1) &&
                    (!TAILQ_EMPTY(&stcb->asoc.asconf_queue))) {
#ifdef SCTP_TIMER_BASED_ASCONF
                        sctp_timer_start(SCTP_TIMER_TYPE_ASCONF,
                            stcb->sctp_ep, stcb,
                            stcb->asoc.primary_destination);
#else
                        sctp_send_asconf(stcb, stcb->asoc.primary_destination,
                            SCTP_ADDR_NOT_LOCKED);
#endif
                }
        }
closed_socket:
        /* Toss the cookie if I can */
        sctp_toss_old_cookies(stcb, asoc);
        if (!TAILQ_EMPTY(&asoc->sent_queue)) {
                /* Restart the timer if we have pending data */
                struct sctp_tmit_chunk *chk;

                chk = TAILQ_FIRST(&asoc->sent_queue);
                sctp_timer_start(SCTP_TIMER_TYPE_SEND, stcb->sctp_ep, stcb, chk->whoTo);
        }
}

static void
sctp_handle_ecn_echo(struct sctp_ecne_chunk *cp,
    struct sctp_tcb *stcb)
{
        struct sctp_nets *net;
        struct sctp_tmit_chunk *lchk;
        struct sctp_ecne_chunk bkup;
        uint8_t override_bit;
        uint32_t tsn, window_data_tsn;
        int len;
        unsigned int pkt_cnt;

        len = ntohs(cp->ch.chunk_length);
        if ((len != sizeof(struct sctp_ecne_chunk)) &&
            (len != sizeof(struct old_sctp_ecne_chunk))) {
                return;
        }
        if (len == sizeof(struct old_sctp_ecne_chunk)) {
                /* Its the old format */
                memcpy(&bkup, cp, sizeof(struct old_sctp_ecne_chunk));
                bkup.num_pkts_since_cwr = htonl(1);
                cp = &bkup;
        }
        SCTP_STAT_INCR(sctps_recvecne);
        tsn = ntohl(cp->tsn);
        pkt_cnt = ntohl(cp->num_pkts_since_cwr);
        lchk = TAILQ_LAST(&stcb->asoc.send_queue, sctpchunk_listhead);
        if (lchk == NULL) {
                window_data_tsn = stcb->asoc.sending_seq - 1;
        } else {
                window_data_tsn = lchk->rec.data.TSN_seq;
        }

        /* Find where it was sent to if possible. */
        net = NULL;
        TAILQ_FOREACH(lchk, &stcb->asoc.sent_queue, sctp_next) {
                if (lchk->rec.data.TSN_seq == tsn) {
                        net = lchk->whoTo;
                        net->ecn_prev_cwnd = lchk->rec.data.cwnd_at_send;
                        break;
                }
                if (SCTP_TSN_GT(lchk->rec.data.TSN_seq, tsn)) {
                        break;
                }
        }
        if (net == NULL) {
                /*
                 * What to do. A previous send of a CWR was possibly lost.
                 * See how old it is, we may have it marked on the actual
                 * net.
                 */
                TAILQ_FOREACH(net, &stcb->asoc.nets, sctp_next) {
                        if (tsn == net->last_cwr_tsn) {
                                /* Found him, send it off */
                                break;
                        }
                }
                if (net == NULL) {
                        /*
                         * If we reach here, we need to send a special CWR
                         * that says hey, we did this a long time ago and
                         * you lost the response.
                         */
                        net = TAILQ_FIRST(&stcb->asoc.nets);
                        if (net == NULL) {
                                /* TSNH */
                                return;
                        }
                        override_bit = SCTP_CWR_REDUCE_OVERRIDE;
                } else {
                        override_bit = 0;
                }
        } else {
                override_bit = 0;
        }
        if (SCTP_TSN_GT(tsn, net->cwr_window_tsn) &&
            ((override_bit & SCTP_CWR_REDUCE_OVERRIDE) == 0)) {
                /*
                 * JRS - Use the congestion control given in the pluggable
                 * CC module
                 */
                stcb->asoc.cc_functions.sctp_cwnd_update_after_ecn_echo(stcb, net, 0, pkt_cnt);
                /*
                 * We reduce once every RTT. So we will only lower cwnd at
                 * the next sending seq i.e. the window_data_tsn
                 */
                net->cwr_window_tsn = window_data_tsn;
                net->ecn_ce_pkt_cnt += pkt_cnt;
                net->lost_cnt = pkt_cnt;
                net->last_cwr_tsn = tsn;
        } else {
                override_bit |= SCTP_CWR_IN_SAME_WINDOW;
                if (SCTP_TSN_GT(tsn, net->last_cwr_tsn) &&
                    ((override_bit & SCTP_CWR_REDUCE_OVERRIDE) == 0)) {
                        /*
                         * Another loss in the same window update how many
                         * marks/packets lost we have had.
                         */
                        int cnt = 1;

                        if (pkt_cnt > net->lost_cnt) {
                                /* Should be the case */
                                cnt = (pkt_cnt - net->lost_cnt);
                                net->ecn_ce_pkt_cnt += cnt;
                        }
                        net->lost_cnt = pkt_cnt;
                        net->last_cwr_tsn = tsn;
                        /*
                         * Most CC functions will ignore this call, since we
                         * are in-window yet of the initial CE the peer saw.
                         */
                        stcb->asoc.cc_functions.sctp_cwnd_update_after_ecn_echo(stcb, net, 1, cnt);
                }
        }
        /*
         * We always send a CWR this way if our previous one was lost our
         * peer will get an update, or if it is not time again to reduce we
         * still get the cwr to the peer. Note we set the override when we
         * could not find the TSN on the chunk or the destination network.
         */
        sctp_send_cwr(stcb, net, net->last_cwr_tsn, override_bit);
}

static void
sctp_handle_ecn_cwr(struct sctp_cwr_chunk *cp, struct sctp_tcb *stcb, struct sctp_nets *net)
{
        /*
         * Here we get a CWR from the peer. We must look in the outqueue and
         * make sure that we have a covered ECNE in the control chunk part.
         * If so remove it.
         */
        struct sctp_tmit_chunk *chk;
        struct sctp_ecne_chunk *ecne;
        int override;
        uint32_t cwr_tsn;

        cwr_tsn = ntohl(cp->tsn);
        override = cp->ch.chunk_flags & SCTP_CWR_REDUCE_OVERRIDE;
        TAILQ_FOREACH(chk, &stcb->asoc.control_send_queue, sctp_next) {
                if (chk->rec.chunk_id.id != SCTP_ECN_ECHO) {
                        continue;
                }
                if ((override == 0) && (chk->whoTo != net)) {
                        /* Must be from the right src unless override is set */
                        continue;
                }
                ecne = mtod(chk->data, struct sctp_ecne_chunk *);
                if (SCTP_TSN_GE(cwr_tsn, ntohl(ecne->tsn))) {
                        /* this covers this ECNE, we can remove it */
                        stcb->asoc.ecn_echo_cnt_onq--;
                        TAILQ_REMOVE(&stcb->asoc.control_send_queue, chk,
                            sctp_next);
                        sctp_m_freem(chk->data);
                        chk->data = NULL;
                        stcb->asoc.ctrl_queue_cnt--;
                        sctp_free_a_chunk(stcb, chk, SCTP_SO_NOT_LOCKED);
                        if (override == 0) {
                                break;
                        }
                }
        }
}

static void
sctp_handle_shutdown_complete(struct sctp_shutdown_complete_chunk *cp SCTP_UNUSED,
    struct sctp_tcb *stcb, struct sctp_nets *net)
{
        struct sctp_association *asoc;

#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
        struct socket *so;

#endif

        SCTPDBG(SCTP_DEBUG_INPUT2,
            "sctp_handle_shutdown_complete: handling SHUTDOWN-COMPLETE\n");
        if (stcb == NULL)
                return;

        asoc = &stcb->asoc;
        /* process according to association state */
        if (SCTP_GET_STATE(asoc) != SCTP_STATE_SHUTDOWN_ACK_SENT) {
                /* unexpected SHUTDOWN-COMPLETE... so ignore... */
                SCTPDBG(SCTP_DEBUG_INPUT2,
                    "sctp_handle_shutdown_complete: not in SCTP_STATE_SHUTDOWN_ACK_SENT --- ignore\n");
                SCTP_TCB_UNLOCK(stcb);
                return;
        }
        /* notify upper layer protocol */
        if (stcb->sctp_socket) {
                sctp_ulp_notify(SCTP_NOTIFY_ASSOC_DOWN, stcb, 0, NULL, SCTP_SO_NOT_LOCKED);
        }
#ifdef INVARIANTS
        if (!TAILQ_EMPTY(&asoc->send_queue) ||
            !TAILQ_EMPTY(&asoc->sent_queue) ||
            !stcb->asoc.ss_functions.sctp_ss_is_empty(stcb, asoc)) {
                panic("Queues are not empty when handling SHUTDOWN-COMPLETE");
        }
#endif
        /* stop the timer */
        sctp_timer_stop(SCTP_TIMER_TYPE_SHUTDOWNACK, stcb->sctp_ep, stcb, net,
            SCTP_FROM_SCTP_INPUT + SCTP_LOC_24);
        SCTP_STAT_INCR_COUNTER32(sctps_shutdown);
        /* free the TCB */
        SCTPDBG(SCTP_DEBUG_INPUT2,
            "sctp_handle_shutdown_complete: calls free-asoc\n");
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
        so = SCTP_INP_SO(stcb->sctp_ep);
        atomic_add_int(&stcb->asoc.refcnt, 1);
        SCTP_TCB_UNLOCK(stcb);
        SCTP_SOCKET_LOCK(so, 1);
        SCTP_TCB_LOCK(stcb);
        atomic_subtract_int(&stcb->asoc.refcnt, 1);
#endif
        (void)sctp_free_assoc(stcb->sctp_ep, stcb, SCTP_NORMAL_PROC,
            SCTP_FROM_SCTP_INPUT + SCTP_LOC_25);
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
        SCTP_SOCKET_UNLOCK(so, 1);
#endif
        return;
}

static int
process_chunk_drop(struct sctp_tcb *stcb, struct sctp_chunk_desc *desc,
    struct sctp_nets *net, uint8_t flg)
{
        switch (desc->chunk_type) {
        case SCTP_DATA:
                /* find the tsn to resend (possibly */
                {
                        uint32_t tsn;
                        struct sctp_tmit_chunk *tp1;

                        tsn = ntohl(desc->tsn_ifany);
                        TAILQ_FOREACH(tp1, &stcb->asoc.sent_queue, sctp_next) {
                                if (tp1->rec.data.TSN_seq == tsn) {
                                        /* found it */
                                        break;
                                }
                                if (SCTP_TSN_GT(tp1->rec.data.TSN_seq, tsn)) {
                                        /* not found */
                                        tp1 = NULL;
                                        break;
                                }
                        }
                        if (tp1 == NULL) {
                                /*
                                 * Do it the other way , aka without paying
                                 * attention to queue seq order.
                                 */
                                SCTP_STAT_INCR(sctps_pdrpdnfnd);
                                TAILQ_FOREACH(tp1, &stcb->asoc.sent_queue, sctp_next) {
                                        if (tp1->rec.data.TSN_seq == tsn) {
                                                /* found it */
                                                break;
                                        }
                                }
                        }
                        if (tp1 == NULL) {
                                SCTP_STAT_INCR(sctps_pdrptsnnf);
                        }
                        if ((tp1) && (tp1->sent < SCTP_DATAGRAM_ACKED)) {
                                uint8_t *ddp;

                                if (((flg & SCTP_BADCRC) == 0) &&
                                    ((flg & SCTP_FROM_MIDDLE_BOX) == 0)) {
                                        return (0);
                                }
                                if ((stcb->asoc.peers_rwnd == 0) &&
                                    ((flg & SCTP_FROM_MIDDLE_BOX) == 0)) {
                                        SCTP_STAT_INCR(sctps_pdrpdiwnp);
                                        return (0);
                                }
                                if (stcb->asoc.peers_rwnd == 0 &&
                                    (flg & SCTP_FROM_MIDDLE_BOX)) {
                                        SCTP_STAT_INCR(sctps_pdrpdizrw);
                                        return (0);
                                }
                                ddp = (uint8_t *) (mtod(tp1->data, caddr_t)+
                                    sizeof(struct sctp_data_chunk));
                                {
                                        unsigned int iii;

                                        for (iii = 0; iii < sizeof(desc->data_bytes);
                                            iii++) {
                                                if (ddp[iii] != desc->data_bytes[iii]) {
                                                        SCTP_STAT_INCR(sctps_pdrpbadd);
                                                        return (-1);
                                                }
                                        }
                                }

                                if (tp1->do_rtt) {
                                        /*
                                         * this guy had a RTO calculation
                                         * pending on it, cancel it
                                         */
                                        if (tp1->whoTo->rto_needed == 0) {
                                                tp1->whoTo->rto_needed = 1;
                                        }
                                        tp1->do_rtt = 0;
                                }
                                SCTP_STAT_INCR(sctps_pdrpmark);
                                if (tp1->sent != SCTP_DATAGRAM_RESEND)
                                        sctp_ucount_incr(stcb->asoc.sent_queue_retran_cnt);
                                /*
                                 * mark it as if we were doing a FR, since
                                 * we will be getting gap ack reports behind
                                 * the info from the router.
                                 */
                                tp1->rec.data.doing_fast_retransmit = 1;
                                /*
                                 * mark the tsn with what sequences can
                                 * cause a new FR.
                                 */
                                if (TAILQ_EMPTY(&stcb->asoc.send_queue)) {
                                        tp1->rec.data.fast_retran_tsn = stcb->asoc.sending_seq;
                                } else {
                                        tp1->rec.data.fast_retran_tsn = (TAILQ_FIRST(&stcb->asoc.send_queue))->rec.data.TSN_seq;
                                }

                                /* restart the timer */
                                sctp_timer_stop(SCTP_TIMER_TYPE_SEND, stcb->sctp_ep,
                                    stcb, tp1->whoTo,
                                    SCTP_FROM_SCTP_INPUT + SCTP_LOC_26);
                                sctp_timer_start(SCTP_TIMER_TYPE_SEND, stcb->sctp_ep,
                                    stcb, tp1->whoTo);

                                /* fix counts and things */
                                if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_FLIGHT_LOGGING_ENABLE) {
                                        sctp_misc_ints(SCTP_FLIGHT_LOG_DOWN_PDRP,
                                            tp1->whoTo->flight_size,
                                            tp1->book_size,
                                            (uintptr_t) stcb,
                                            tp1->rec.data.TSN_seq);
                                }
                                if (tp1->sent < SCTP_DATAGRAM_RESEND) {
                                        sctp_flight_size_decrease(tp1);
                                        sctp_total_flight_decrease(stcb, tp1);
                                }
                                tp1->sent = SCTP_DATAGRAM_RESEND;
                        } {
                                /* audit code */
                                unsigned int audit;

                                audit = 0;
                                TAILQ_FOREACH(tp1, &stcb->asoc.sent_queue, sctp_next) {
                                        if (tp1->sent == SCTP_DATAGRAM_RESEND)
                                                audit++;
                                }
                                TAILQ_FOREACH(tp1, &stcb->asoc.control_send_queue,
                                    sctp_next) {
                                        if (tp1->sent == SCTP_DATAGRAM_RESEND)
                                                audit++;
                                }
                                if (audit != stcb->asoc.sent_queue_retran_cnt) {
                                        SCTP_PRINTF("**Local Audit finds cnt:%d asoc cnt:%d\n",
                                            audit, stcb->asoc.sent_queue_retran_cnt);
#ifndef SCTP_AUDITING_ENABLED
                                        stcb->asoc.sent_queue_retran_cnt = audit;
#endif
                                }
                        }
                }
                break;
        case SCTP_ASCONF:
                {
                        struct sctp_tmit_chunk *asconf;

                        TAILQ_FOREACH(asconf, &stcb->asoc.control_send_queue,
                            sctp_next) {
                                if (asconf->rec.chunk_id.id == SCTP_ASCONF) {
                                        break;
                                }
                        }
                        if (asconf) {
                                if (asconf->sent != SCTP_DATAGRAM_RESEND)
                                        sctp_ucount_incr(stcb->asoc.sent_queue_retran_cnt);
                                asconf->sent = SCTP_DATAGRAM_RESEND;
                                asconf->snd_count--;
                        }
                }
                break;
        case SCTP_INITIATION:
                /* resend the INIT */
                stcb->asoc.dropped_special_cnt++;
                if (stcb->asoc.dropped_special_cnt < SCTP_RETRY_DROPPED_THRESH) {
                        /*
                         * If we can get it in, in a few attempts we do
                         * this, otherwise we let the timer fire.
                         */
                        sctp_timer_stop(SCTP_TIMER_TYPE_INIT, stcb->sctp_ep,
                            stcb, net,
                            SCTP_FROM_SCTP_INPUT + SCTP_LOC_27);
                        sctp_send_initiate(stcb->sctp_ep, stcb, SCTP_SO_NOT_LOCKED);
                }
                break;
        case SCTP_SELECTIVE_ACK:
        case SCTP_NR_SELECTIVE_ACK:
                /* resend the sack */
                sctp_send_sack(stcb, SCTP_SO_NOT_LOCKED);
                break;
        case SCTP_HEARTBEAT_REQUEST:
                /* resend a demand HB */
                if ((stcb->asoc.overall_error_count + 3) < stcb->asoc.max_send_times) {
                        /*
                         * Only retransmit if we KNOW we wont destroy the
                         * tcb
                         */
                        sctp_send_hb(stcb, net, SCTP_SO_NOT_LOCKED);
                }
                break;
        case SCTP_SHUTDOWN:
                sctp_send_shutdown(stcb, net);
                break;
        case SCTP_SHUTDOWN_ACK:
                sctp_send_shutdown_ack(stcb, net);
                break;
        case SCTP_COOKIE_ECHO:
                {
                        struct sctp_tmit_chunk *cookie;

                        cookie = NULL;
                        TAILQ_FOREACH(cookie, &stcb->asoc.control_send_queue,
                            sctp_next) {
                                if (cookie->rec.chunk_id.id == SCTP_COOKIE_ECHO) {
                                        break;
                                }
                        }
                        if (cookie) {
                                if (cookie->sent != SCTP_DATAGRAM_RESEND)
                                        sctp_ucount_incr(stcb->asoc.sent_queue_retran_cnt);
                                cookie->sent = SCTP_DATAGRAM_RESEND;
                                sctp_stop_all_cookie_timers(stcb);
                        }
                }
                break;
        case SCTP_COOKIE_ACK:
                sctp_send_cookie_ack(stcb);
                break;
        case SCTP_ASCONF_ACK:
                /* resend last asconf ack */
                sctp_send_asconf_ack(stcb);
                break;
        case SCTP_FORWARD_CUM_TSN:
                send_forward_tsn(stcb, &stcb->asoc);
                break;
                /* can't do anything with these */
        case SCTP_PACKET_DROPPED:
        case SCTP_INITIATION_ACK:       /* this should not happen */
        case SCTP_HEARTBEAT_ACK:
        case SCTP_ABORT_ASSOCIATION:
        case SCTP_OPERATION_ERROR:
        case SCTP_SHUTDOWN_COMPLETE:
        case SCTP_ECN_ECHO:
        case SCTP_ECN_CWR:
        default:
                break;
        }
        return (0);
}

void
sctp_reset_in_stream(struct sctp_tcb *stcb, uint32_t number_entries, uint16_t * list)
{
        uint32_t i;
        uint16_t temp;

        /*
         * We set things to 0xffff since this is the last delivered sequence
         * and we will be sending in 0 after the reset.
         */

        if (number_entries) {
                for (i = 0; i < number_entries; i++) {
                        temp = ntohs(list[i]);
                        if (temp >= stcb->asoc.streamincnt) {
                                continue;
                        }
                        stcb->asoc.strmin[temp].last_sequence_delivered = 0xffff;
                }
        } else {
                list = NULL;
                for (i = 0; i < stcb->asoc.streamincnt; i++) {
                        stcb->asoc.strmin[i].last_sequence_delivered = 0xffff;
                }
        }
        sctp_ulp_notify(SCTP_NOTIFY_STR_RESET_RECV, stcb, number_entries, (void *)list, SCTP_SO_NOT_LOCKED);
}

static void
sctp_reset_out_streams(struct sctp_tcb *stcb, uint32_t number_entries, uint16_t * list)
{
        uint32_t i;
        uint16_t temp;

        if (number_entries > 0) {
                for (i = 0; i < number_entries; i++) {
                        temp = ntohs(list[i]);
                        if (temp >= stcb->asoc.streamoutcnt) {
                                /* no such stream */
                                continue;
                        }
                        stcb->asoc.strmout[temp].next_sequence_send = 0;
                }
        } else {
                for (i = 0; i < stcb->asoc.streamoutcnt; i++) {
                        stcb->asoc.strmout[i].next_sequence_send = 0;
                }
        }
        sctp_ulp_notify(SCTP_NOTIFY_STR_RESET_SEND, stcb, number_entries, (void *)list, SCTP_SO_NOT_LOCKED);
}

static void
sctp_reset_clear_pending(struct sctp_tcb *stcb, uint32_t number_entries, uint16_t * list)
{
        uint32_t i;
        uint16_t temp;

        if (number_entries > 0) {
                for (i = 0; i < number_entries; i++) {
                        temp = ntohs(list[i]);
                        if (temp >= stcb->asoc.streamoutcnt) {
                                /* no such stream */
                                continue;
                        }
                        stcb->asoc.strmout[temp].state = SCTP_STREAM_OPEN;
                }
        } else {
                for (i = 0; i < stcb->asoc.streamoutcnt; i++) {
                        stcb->asoc.strmout[i].state = SCTP_STREAM_OPEN;
                }
        }
}


struct sctp_stream_reset_request *
sctp_find_stream_reset(struct sctp_tcb *stcb, uint32_t seq, struct sctp_tmit_chunk **bchk)
{
        struct sctp_association *asoc;
        struct sctp_chunkhdr *ch;
        struct sctp_stream_reset_request *r;
        struct sctp_tmit_chunk *chk;
        int len, clen;

        asoc = &stcb->asoc;
        if (TAILQ_EMPTY(&stcb->asoc.control_send_queue)) {
                asoc->stream_reset_outstanding = 0;
                return (NULL);
        }
        if (stcb->asoc.str_reset == NULL) {
                asoc->stream_reset_outstanding = 0;
                return (NULL);
        }
        chk = stcb->asoc.str_reset;
        if (chk->data == NULL) {
                return (NULL);
        }
        if (bchk) {
                /* he wants a copy of the chk pointer */
                *bchk = chk;
        }
        clen = chk->send_size;
        ch = mtod(chk->data, struct sctp_chunkhdr *);
        r = (struct sctp_stream_reset_request *)(ch + 1);
        if (ntohl(r->request_seq) == seq) {
                /* found it */
                return (r);
        }
        len = SCTP_SIZE32(ntohs(r->ph.param_length));
        if (clen > (len + (int)sizeof(struct sctp_chunkhdr))) {
                /* move to the next one, there can only be a max of two */
                r = (struct sctp_stream_reset_request *)((caddr_t)r + len);
                if (ntohl(r->request_seq) == seq) {
                        return (r);
                }
        }
        /* that seq is not here */
        return (NULL);
}

static void
sctp_clean_up_stream_reset(struct sctp_tcb *stcb)
{
        struct sctp_association *asoc;
        struct sctp_tmit_chunk *chk = stcb->asoc.str_reset;

        if (stcb->asoc.str_reset == NULL) {
                return;
        }
        asoc = &stcb->asoc;

        sctp_timer_stop(SCTP_TIMER_TYPE_STRRESET, stcb->sctp_ep, stcb,
            chk->whoTo, SCTP_FROM_SCTP_INPUT + SCTP_LOC_28);
        TAILQ_REMOVE(&asoc->control_send_queue,
            chk,
            sctp_next);
        if (chk->data) {
                sctp_m_freem(chk->data);
                chk->data = NULL;
        }
        asoc->ctrl_queue_cnt--;
        sctp_free_a_chunk(stcb, chk, SCTP_SO_NOT_LOCKED);
        /* sa_ignore NO_NULL_CHK */
        stcb->asoc.str_reset = NULL;
}


static int
sctp_handle_stream_reset_response(struct sctp_tcb *stcb,
    uint32_t seq, uint32_t action,
    struct sctp_stream_reset_response *respin)
{
        uint16_t type;
        int lparm_len;
        struct sctp_association *asoc = &stcb->asoc;
        struct sctp_tmit_chunk *chk;
        struct sctp_stream_reset_request *req_param;
        struct sctp_stream_reset_out_request *req_out_param;
        struct sctp_stream_reset_in_request *req_in_param;
        uint32_t number_entries;

        if (asoc->stream_reset_outstanding == 0) {
                /* duplicate */
                return (0);
        }
        if (seq == stcb->asoc.str_reset_seq_out) {
                req_param = sctp_find_stream_reset(stcb, seq, &chk);
                if (req_param != NULL) {
                        stcb->asoc.str_reset_seq_out++;
                        type = ntohs(req_param->ph.param_type);
                        lparm_len = ntohs(req_param->ph.param_length);
                        if (type == SCTP_STR_RESET_OUT_REQUEST) {
                                int no_clear = 0;

                                req_out_param = (struct sctp_stream_reset_out_request *)req_param;
                                number_entries = (lparm_len - sizeof(struct sctp_stream_reset_out_request)) / sizeof(uint16_t);
                                asoc->stream_reset_out_is_outstanding = 0;
                                if (asoc->stream_reset_outstanding)
                                        asoc->stream_reset_outstanding--;
                                if (action == SCTP_STREAM_RESET_RESULT_PERFORMED) {
                                        /* do it */
                                        sctp_reset_out_streams(stcb, number_entries, req_out_param->list_of_streams);
                                } else if (action == SCTP_STREAM_RESET_RESULT_DENIED) {
                                        sctp_ulp_notify(SCTP_NOTIFY_STR_RESET_DENIED_OUT, stcb, number_entries, req_out_param->list_of_streams, SCTP_SO_NOT_LOCKED);
                                } else if (action == SCTP_STREAM_RESET_RESULT_IN_PROGRESS) {
                                        /*
                                         * Set it up so we don't stop
                                         * retransmitting
                                         */
                                        asoc->stream_reset_outstanding++;
                                        stcb->asoc.str_reset_seq_out--;
                                        asoc->stream_reset_out_is_outstanding = 1;
                                        no_clear = 1;
                                } else {
                                        sctp_ulp_notify(SCTP_NOTIFY_STR_RESET_FAILED_OUT, stcb, number_entries, req_out_param->list_of_streams, SCTP_SO_NOT_LOCKED);
                                }
                                if (no_clear == 0) {
                                        sctp_reset_clear_pending(stcb, number_entries, req_out_param->list_of_streams);
                                }
                        } else if (type == SCTP_STR_RESET_IN_REQUEST) {
                                req_in_param = (struct sctp_stream_reset_in_request *)req_param;
                                number_entries = (lparm_len - sizeof(struct sctp_stream_reset_in_request)) / sizeof(uint16_t);
                                if (asoc->stream_reset_outstanding)
                                        asoc->stream_reset_outstanding--;
                                if (action == SCTP_STREAM_RESET_RESULT_DENIED) {
                                        sctp_ulp_notify(SCTP_NOTIFY_STR_RESET_DENIED_IN, stcb,
                                            number_entries, req_in_param->list_of_streams, SCTP_SO_NOT_LOCKED);
                                } else if (action != SCTP_STREAM_RESET_RESULT_PERFORMED) {
                                        sctp_ulp_notify(SCTP_NOTIFY_STR_RESET_FAILED_IN, stcb,
                                            number_entries, req_in_param->list_of_streams, SCTP_SO_NOT_LOCKED);
                                }
                        } else if (type == SCTP_STR_RESET_ADD_OUT_STREAMS) {
                                /* Ok we now may have more streams */
                                int num_stream;

                                num_stream = stcb->asoc.strm_pending_add_size;
                                if (num_stream > (stcb->asoc.strm_realoutsize - stcb->asoc.streamoutcnt)) {
                                        /* TSNH */
                                        num_stream = stcb->asoc.strm_realoutsize - stcb->asoc.streamoutcnt;
                                }
                                stcb->asoc.strm_pending_add_size = 0;
                                if (asoc->stream_reset_outstanding)
                                        asoc->stream_reset_outstanding--;
                                if (action == SCTP_STREAM_RESET_RESULT_PERFORMED) {
                                        /* Put the new streams into effect */
                                        int i;

                                        for (i = asoc->streamoutcnt; i < (asoc->streamoutcnt + num_stream); i++) {
                                                asoc->strmout[i].state = SCTP_STREAM_OPEN;
                                        }
                                        asoc->streamoutcnt += num_stream;
                                        sctp_notify_stream_reset_add(stcb, stcb->asoc.streamincnt, stcb->asoc.streamoutcnt, 0);
                                } else if (action == SCTP_STREAM_RESET_RESULT_DENIED) {
                                        sctp_notify_stream_reset_add(stcb, stcb->asoc.streamincnt, stcb->asoc.streamoutcnt,
                                            SCTP_STREAM_CHANGE_DENIED);
                                } else {
                                        sctp_notify_stream_reset_add(stcb, stcb->asoc.streamincnt, stcb->asoc.streamoutcnt,
                                            SCTP_STREAM_CHANGE_FAILED);
                                }
                        } else if (type == SCTP_STR_RESET_ADD_IN_STREAMS) {
                                if (asoc->stream_reset_outstanding)
                                        asoc->stream_reset_outstanding--;
                                if (action == SCTP_STREAM_RESET_RESULT_DENIED) {
                                        sctp_notify_stream_reset_add(stcb, stcb->asoc.streamincnt, stcb->asoc.streamoutcnt,
                                            SCTP_STREAM_CHANGE_DENIED);
                                } else if (action != SCTP_STREAM_RESET_RESULT_PERFORMED) {
                                        sctp_notify_stream_reset_add(stcb, stcb->asoc.streamincnt, stcb->asoc.streamoutcnt,
                                            SCTP_STREAM_CHANGE_FAILED);
                                }
                        } else if (type == SCTP_STR_RESET_TSN_REQUEST) {
                                /**
                                 * a) Adopt the new in tsn.
                                 * b) reset the map
                                 * c) Adopt the new out-tsn
                                 */
                                struct sctp_stream_reset_response_tsn *resp;
                                struct sctp_forward_tsn_chunk fwdtsn;
                                int abort_flag = 0;

                                if (respin == NULL) {
                                        /* huh ? */
                                        return (0);
                                }
                                if (ntohs(respin->ph.param_length) < sizeof(struct sctp_stream_reset_response_tsn)) {
                                        return (0);
                                }
                                if (action == SCTP_STREAM_RESET_RESULT_PERFORMED) {
                                        resp = (struct sctp_stream_reset_response_tsn *)respin;
                                        asoc->stream_reset_outstanding--;
                                        fwdtsn.ch.chunk_length = htons(sizeof(struct sctp_forward_tsn_chunk));
                                        fwdtsn.ch.chunk_type = SCTP_FORWARD_CUM_TSN;
                                        fwdtsn.new_cumulative_tsn = htonl(ntohl(resp->senders_next_tsn) - 1);
                                        sctp_handle_forward_tsn(stcb, &fwdtsn, &abort_flag, NULL, 0);
                                        if (abort_flag) {
                                                return (1);
                                        }
                                        stcb->asoc.highest_tsn_inside_map = (ntohl(resp->senders_next_tsn) - 1);
                                        if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_MAP_LOGGING_ENABLE) {
                                                sctp_log_map(0, 7, asoc->highest_tsn_inside_map, SCTP_MAP_SLIDE_RESULT);
                                        }
                                        stcb->asoc.tsn_last_delivered = stcb->asoc.cumulative_tsn = stcb->asoc.highest_tsn_inside_map;
                                        stcb->asoc.mapping_array_base_tsn = ntohl(resp->senders_next_tsn);
                                        memset(stcb->asoc.mapping_array, 0, stcb->asoc.mapping_array_size);

                                        stcb->asoc.highest_tsn_inside_nr_map = stcb->asoc.highest_tsn_inside_map;
                                        memset(stcb->asoc.nr_mapping_array, 0, stcb->asoc.mapping_array_size);

                                        stcb->asoc.sending_seq = ntohl(resp->receivers_next_tsn);
                                        stcb->asoc.last_acked_seq = stcb->asoc.cumulative_tsn;

                                        sctp_reset_out_streams(stcb, 0, (uint16_t *) NULL);
                                        sctp_reset_in_stream(stcb, 0, (uint16_t *) NULL);
                                        sctp_notify_stream_reset_tsn(stcb, stcb->asoc.sending_seq, (stcb->asoc.mapping_array_base_tsn + 1), 0);
                                } else if (action == SCTP_STREAM_RESET_RESULT_DENIED) {
                                        sctp_notify_stream_reset_tsn(stcb, stcb->asoc.sending_seq, (stcb->asoc.mapping_array_base_tsn + 1),
                                            SCTP_ASSOC_RESET_DENIED);
                                } else {
                                        sctp_notify_stream_reset_tsn(stcb, stcb->asoc.sending_seq, (stcb->asoc.mapping_array_base_tsn + 1),
                                            SCTP_ASSOC_RESET_FAILED);
                                }
                        }
                        /* get rid of the request and get the request flags */
                        if (asoc->stream_reset_outstanding == 0) {
                                sctp_clean_up_stream_reset(stcb);
                        }
                }
        }
        if (asoc->stream_reset_outstanding == 0) {
                sctp_send_stream_reset_out_if_possible(stcb, SCTP_SO_NOT_LOCKED);
        }
        return (0);
}

static void
sctp_handle_str_reset_request_in(struct sctp_tcb *stcb,
    struct sctp_tmit_chunk *chk,
    struct sctp_stream_reset_in_request *req, int trunc)
{
        uint32_t seq;
        int len, i;
        int number_entries;
        uint16_t temp;

        /*
         * peer wants me to send a str-reset to him for my outgoing seq's if
         * seq_in is right.
         */
        struct sctp_association *asoc = &stcb->asoc;

        seq = ntohl(req->request_seq);
        if (asoc->str_reset_seq_in == seq) {
                asoc->last_reset_action[1] = asoc->last_reset_action[0];
                if (!(asoc->local_strreset_support & SCTP_ENABLE_RESET_STREAM_REQ)) {
                        asoc->last_reset_action[0] = SCTP_STREAM_RESET_RESULT_DENIED;
                } else if (trunc) {
                        /* Can't do it, since they exceeded our buffer size  */
                        asoc->last_reset_action[0] = SCTP_STREAM_RESET_RESULT_DENIED;
                } else if (stcb->asoc.stream_reset_out_is_outstanding == 0) {
                        len = ntohs(req->ph.param_length);
                        number_entries = ((len - sizeof(struct sctp_stream_reset_in_request)) / sizeof(uint16_t));
                        if (number_entries) {
                                for (i = 0; i < number_entries; i++) {
                                        temp = ntohs(req->list_of_streams[i]);
                                        if (temp >= stcb->asoc.streamoutcnt) {
                                                asoc->last_reset_action[0] = SCTP_STREAM_RESET_RESULT_DENIED;
                                                goto bad_boy;
                                        }
                                        req->list_of_streams[i] = temp;
                                }
                                for (i = 0; i < number_entries; i++) {
                                        if (stcb->asoc.strmout[req->list_of_streams[i]].state == SCTP_STREAM_OPEN) {
                                                stcb->asoc.strmout[req->list_of_streams[i]].state = SCTP_STREAM_RESET_PENDING;
                                        }
                                }
                        } else {
                                /* Its all */
                                for (i = 0; i < stcb->asoc.streamoutcnt; i++) {
                                        if (stcb->asoc.strmout[i].state == SCTP_STREAM_OPEN)
                                                stcb->asoc.strmout[i].state = SCTP_STREAM_RESET_PENDING;
                                }
                        }
                        asoc->last_reset_action[0] = SCTP_STREAM_RESET_RESULT_PERFORMED;
                } else {
                        /* Can't do it, since we have sent one out */
                        asoc->last_reset_action[0] = SCTP_STREAM_RESET_RESULT_ERR_IN_PROGRESS;
                }
bad_boy:
                sctp_add_stream_reset_result(chk, seq, asoc->last_reset_action[0]);
                asoc->str_reset_seq_in++;
        } else if (asoc->str_reset_seq_in - 1 == seq) {
                sctp_add_stream_reset_result(chk, seq, asoc->last_reset_action[0]);
        } else if (asoc->str_reset_seq_in - 2 == seq) {
                sctp_add_stream_reset_result(chk, seq, asoc->last_reset_action[1]);
        } else {
                sctp_add_stream_reset_result(chk, seq, SCTP_STREAM_RESET_RESULT_ERR_BAD_SEQNO);
        }
        sctp_send_stream_reset_out_if_possible(stcb, SCTP_SO_NOT_LOCKED);
}

static int
sctp_handle_str_reset_request_tsn(struct sctp_tcb *stcb,
    struct sctp_tmit_chunk *chk,
    struct sctp_stream_reset_tsn_request *req)
{
        /* reset all in and out and update the tsn */
        /*
         * A) reset my str-seq's on in and out. B) Select a receive next,
         * and set cum-ack to it. Also process this selected number as a
         * fwd-tsn as well. C) set in the response my next sending seq.
         */
        struct sctp_forward_tsn_chunk fwdtsn;
        struct sctp_association *asoc = &stcb->asoc;
        int abort_flag = 0;
        uint32_t seq;

        seq = ntohl(req->request_seq);
        if (asoc->str_reset_seq_in == seq) {
                asoc->last_reset_action[1] = stcb->asoc.last_reset_action[0];
                if (!(asoc->local_strreset_support & SCTP_ENABLE_CHANGE_ASSOC_REQ)) {
                        asoc->last_reset_action[0] = SCTP_STREAM_RESET_RESULT_DENIED;
                } else {
                        fwdtsn.ch.chunk_length = htons(sizeof(struct sctp_forward_tsn_chunk));
                        fwdtsn.ch.chunk_type = SCTP_FORWARD_CUM_TSN;
                        fwdtsn.ch.chunk_flags = 0;
                        fwdtsn.new_cumulative_tsn = htonl(stcb->asoc.highest_tsn_inside_map + 1);
                        sctp_handle_forward_tsn(stcb, &fwdtsn, &abort_flag, NULL, 0);
                        if (abort_flag) {
                                return (1);
                        }
                        asoc->highest_tsn_inside_map += SCTP_STREAM_RESET_TSN_DELTA;
                        if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_MAP_LOGGING_ENABLE) {
                                sctp_log_map(0, 10, asoc->highest_tsn_inside_map, SCTP_MAP_SLIDE_RESULT);
                        }
                        asoc->tsn_last_delivered = asoc->cumulative_tsn = asoc->highest_tsn_inside_map;
                        asoc->mapping_array_base_tsn = asoc->highest_tsn_inside_map + 1;
                        memset(asoc->mapping_array, 0, asoc->mapping_array_size);
                        asoc->highest_tsn_inside_nr_map = asoc->highest_tsn_inside_map;
                        memset(asoc->nr_mapping_array, 0, asoc->mapping_array_size);
                        atomic_add_int(&asoc->sending_seq, 1);
                        /* save off historical data for retrans */
                        asoc->last_sending_seq[1] = asoc->last_sending_seq[0];
                        asoc->last_sending_seq[0] = asoc->sending_seq;
                        asoc->last_base_tsnsent[1] = asoc->last_base_tsnsent[0];
                        asoc->last_base_tsnsent[0] = asoc->mapping_array_base_tsn;
                        sctp_reset_out_streams(stcb, 0, (uint16_t *) NULL);
                        sctp_reset_in_stream(stcb, 0, (uint16_t *) NULL);
                        asoc->last_reset_action[0] = SCTP_STREAM_RESET_RESULT_PERFORMED;
                        sctp_notify_stream_reset_tsn(stcb, asoc->sending_seq, (asoc->mapping_array_base_tsn + 1), 0);
                }
                sctp_add_stream_reset_result_tsn(chk, seq, asoc->last_reset_action[0],
                    asoc->last_sending_seq[0], asoc->last_base_tsnsent[0]);
                asoc->str_reset_seq_in++;
        } else if (asoc->str_reset_seq_in - 1 == seq) {
                sctp_add_stream_reset_result_tsn(chk, seq, asoc->last_reset_action[0],
                    asoc->last_sending_seq[0], asoc->last_base_tsnsent[0]);
        } else if (asoc->str_reset_seq_in - 2 == seq) {
                sctp_add_stream_reset_result_tsn(chk, seq, asoc->last_reset_action[1],
                    asoc->last_sending_seq[1], asoc->last_base_tsnsent[1]);
        } else {
                sctp_add_stream_reset_result(chk, seq, SCTP_STREAM_RESET_RESULT_ERR_BAD_SEQNO);
        }
        return (0);
}

static void
sctp_handle_str_reset_request_out(struct sctp_tcb *stcb,
    struct sctp_tmit_chunk *chk,
    struct sctp_stream_reset_out_request *req, int trunc)
{
        uint32_t seq, tsn;
        int number_entries, len;
        struct sctp_association *asoc = &stcb->asoc;

        seq = ntohl(req->request_seq);

        /* now if its not a duplicate we process it */
        if (asoc->str_reset_seq_in == seq) {
                len = ntohs(req->ph.param_length);
                number_entries = ((len - sizeof(struct sctp_stream_reset_out_request)) / sizeof(uint16_t));
                /*
                 * the sender is resetting, handle the list issue.. we must
                 * a) verify if we can do the reset, if so no problem b) If
                 * we can't do the reset we must copy the request. c) queue
                 * it, and setup the data in processor to trigger it off
                 * when needed and dequeue all the queued data.
                 */
                tsn = ntohl(req->send_reset_at_tsn);

                /* move the reset action back one */
                asoc->last_reset_action[1] = asoc->last_reset_action[0];
                if (!(asoc->local_strreset_support & SCTP_ENABLE_RESET_STREAM_REQ)) {
                        asoc->last_reset_action[0] = SCTP_STREAM_RESET_RESULT_DENIED;
                } else if (trunc) {
                        asoc->last_reset_action[0] = SCTP_STREAM_RESET_RESULT_DENIED;
                } else if (SCTP_TSN_GE(asoc->cumulative_tsn, tsn)) {
                        /* we can do it now */
                        sctp_reset_in_stream(stcb, number_entries, req->list_of_streams);
                        asoc->last_reset_action[0] = SCTP_STREAM_RESET_RESULT_PERFORMED;
                } else {
                        /*
                         * we must queue it up and thus wait for the TSN's
                         * to arrive that are at or before tsn
                         */
                        struct sctp_stream_reset_list *liste;
                        int siz;

                        siz = sizeof(struct sctp_stream_reset_list) + (number_entries * sizeof(uint16_t));
                        SCTP_MALLOC(liste, struct sctp_stream_reset_list *,
                            siz, SCTP_M_STRESET);
                        if (liste == NULL) {
                                /* gak out of memory */
                                asoc->last_reset_action[0] = SCTP_STREAM_RESET_RESULT_DENIED;
                                sctp_add_stream_reset_result(chk, seq, asoc->last_reset_action[0]);
                                return;
                        }
                        liste->seq = seq;
                        liste->tsn = tsn;
                        liste->number_entries = number_entries;
                        memcpy(&liste->list_of_streams, req->list_of_streams, number_entries * sizeof(uint16_t));
                        TAILQ_INSERT_TAIL(&asoc->resetHead, liste, next_resp);
                        asoc->last_reset_action[0] = SCTP_STREAM_RESET_RESULT_IN_PROGRESS;
                }
                sctp_add_stream_reset_result(chk, seq, asoc->last_reset_action[0]);
                asoc->str_reset_seq_in++;
        } else if ((asoc->str_reset_seq_in - 1) == seq) {
                /*
                 * one seq back, just echo back last action since my
                 * response was lost.
                 */
                sctp_add_stream_reset_result(chk, seq, asoc->last_reset_action[0]);
        } else if ((asoc->str_reset_seq_in - 2) == seq) {
                /*
                 * two seq back, just echo back last action since my
                 * response was lost.
                 */
                sctp_add_stream_reset_result(chk, seq, asoc->last_reset_action[1]);
        } else {
                sctp_add_stream_reset_result(chk, seq, SCTP_STREAM_RESET_RESULT_ERR_BAD_SEQNO);
        }
}

static void
sctp_handle_str_reset_add_strm(struct sctp_tcb *stcb, struct sctp_tmit_chunk *chk,
    struct sctp_stream_reset_add_strm *str_add)
{
        /*
         * Peer is requesting to add more streams. If its within our
         * max-streams we will allow it.
         */
        uint32_t num_stream, i;
        uint32_t seq;
        struct sctp_association *asoc = &stcb->asoc;
        struct sctp_queued_to_read *ctl, *nctl;

        /* Get the number. */
        seq = ntohl(str_add->request_seq);
        num_stream = ntohs(str_add->number_of_streams);
        /* Now what would be the new total? */
        if (asoc->str_reset_seq_in == seq) {
                num_stream += stcb->asoc.streamincnt;
                stcb->asoc.last_reset_action[1] = stcb->asoc.last_reset_action[0];
                if (!(asoc->local_strreset_support & SCTP_ENABLE_CHANGE_ASSOC_REQ)) {
                        asoc->last_reset_action[0] = SCTP_STREAM_RESET_RESULT_DENIED;
                } else if ((num_stream > stcb->asoc.max_inbound_streams) ||
                    (num_stream > 0xffff)) {
                        /* We must reject it they ask for to many */
        denied:
                        stcb->asoc.last_reset_action[0] = SCTP_STREAM_RESET_RESULT_DENIED;
                } else {
                        /* Ok, we can do that :-) */
                        struct sctp_stream_in *oldstrm;

                        /* save off the old */
                        oldstrm = stcb->asoc.strmin;
                        SCTP_MALLOC(stcb->asoc.strmin, struct sctp_stream_in *,
                            (num_stream * sizeof(struct sctp_stream_in)),
                            SCTP_M_STRMI);
                        if (stcb->asoc.strmin == NULL) {
                                stcb->asoc.strmin = oldstrm;
                                goto denied;
                        }
                        /* copy off the old data */
                        for (i = 0; i < stcb->asoc.streamincnt; i++) {
                                TAILQ_INIT(&stcb->asoc.strmin[i].inqueue);
                                stcb->asoc.strmin[i].stream_no = i;
                                stcb->asoc.strmin[i].last_sequence_delivered = oldstrm[i].last_sequence_delivered;
                                stcb->asoc.strmin[i].delivery_started = oldstrm[i].delivery_started;
                                /* now anything on those queues? */
                                TAILQ_FOREACH_SAFE(ctl, &oldstrm[i].inqueue, next, nctl) {
                                        TAILQ_REMOVE(&oldstrm[i].inqueue, ctl, next);
                                        TAILQ_INSERT_TAIL(&stcb->asoc.strmin[i].inqueue, ctl, next);
                                }
                        }
                        /* Init the new streams */
                        for (i = stcb->asoc.streamincnt; i < num_stream; i++) {
                                TAILQ_INIT(&stcb->asoc.strmin[i].inqueue);
                                stcb->asoc.strmin[i].stream_no = i;
                                stcb->asoc.strmin[i].last_sequence_delivered = 0xffff;
                                stcb->asoc.strmin[i].delivery_started = 0;
                        }
                        SCTP_FREE(oldstrm, SCTP_M_STRMI);
                        /* update the size */
                        stcb->asoc.streamincnt = num_stream;
                        stcb->asoc.last_reset_action[0] = SCTP_STREAM_RESET_RESULT_PERFORMED;
                        sctp_notify_stream_reset_add(stcb, stcb->asoc.streamincnt, stcb->asoc.streamoutcnt, 0);
                }
                sctp_add_stream_reset_result(chk, seq, asoc->last_reset_action[0]);
                asoc->str_reset_seq_in++;
        } else if ((asoc->str_reset_seq_in - 1) == seq) {
                /*
                 * one seq back, just echo back last action since my
                 * response was lost.
                 */
                sctp_add_stream_reset_result(chk, seq, asoc->last_reset_action[0]);
        } else if ((asoc->str_reset_seq_in - 2) == seq) {
                /*
                 * two seq back, just echo back last action since my
                 * response was lost.
                 */
                sctp_add_stream_reset_result(chk, seq, asoc->last_reset_action[1]);
        } else {
                sctp_add_stream_reset_result(chk, seq, SCTP_STREAM_RESET_RESULT_ERR_BAD_SEQNO);

        }
}

static void
sctp_handle_str_reset_add_out_strm(struct sctp_tcb *stcb, struct sctp_tmit_chunk *chk,
    struct sctp_stream_reset_add_strm *str_add)
{
        /*
         * Peer is requesting to add more streams. If its within our
         * max-streams we will allow it.
         */
        uint16_t num_stream;
        uint32_t seq;
        struct sctp_association *asoc = &stcb->asoc;

        /* Get the number. */
        seq = ntohl(str_add->request_seq);
        num_stream = ntohs(str_add->number_of_streams);
        /* Now what would be the new total? */
        if (asoc->str_reset_seq_in == seq) {
                stcb->asoc.last_reset_action[1] = stcb->asoc.last_reset_action[0];
                if (!(asoc->local_strreset_support & SCTP_ENABLE_CHANGE_ASSOC_REQ)) {
                        asoc->last_reset_action[0] = SCTP_STREAM_RESET_RESULT_DENIED;
                } else if (stcb->asoc.stream_reset_outstanding) {
                        /* We must reject it we have something pending */
                        stcb->asoc.last_reset_action[0] = SCTP_STREAM_RESET_RESULT_ERR_IN_PROGRESS;
                } else {
                        /* Ok, we can do that :-) */
                        int mychk;

                        mychk = stcb->asoc.streamoutcnt;
                        mychk += num_stream;
                        if (mychk < 0x10000) {
                                stcb->asoc.last_reset_action[0] = SCTP_STREAM_RESET_RESULT_PERFORMED;
                                if (sctp_send_str_reset_req(stcb, 0, NULL, 0, 0, 1, num_stream, 0, 1)) {
                                        stcb->asoc.last_reset_action[0] = SCTP_STREAM_RESET_RESULT_DENIED;
                                }
                        } else {
                                stcb->asoc.last_reset_action[0] = SCTP_STREAM_RESET_RESULT_DENIED;
                        }
                }
                sctp_add_stream_reset_result(chk, seq, stcb->asoc.last_reset_action[0]);
                asoc->str_reset_seq_in++;
        } else if ((asoc->str_reset_seq_in - 1) == seq) {
                /*
                 * one seq back, just echo back last action since my
                 * response was lost.
                 */
                sctp_add_stream_reset_result(chk, seq, asoc->last_reset_action[0]);
        } else if ((asoc->str_reset_seq_in - 2) == seq) {
                /*
                 * two seq back, just echo back last action since my
                 * response was lost.
                 */
                sctp_add_stream_reset_result(chk, seq, asoc->last_reset_action[1]);
        } else {
                sctp_add_stream_reset_result(chk, seq, SCTP_STREAM_RESET_RESULT_ERR_BAD_SEQNO);
        }
}

#ifdef __GNUC__
__attribute__((noinline))
#endif
        static int
            sctp_handle_stream_reset(struct sctp_tcb *stcb, struct mbuf *m, int offset,
        struct sctp_chunkhdr *ch_req)
{
        uint16_t remaining_length, param_len, ptype;
        struct sctp_paramhdr pstore;
        uint8_t cstore[SCTP_CHUNK_BUFFER_SIZE];
        uint32_t seq = 0;
        int num_req = 0;
        int trunc = 0;
        struct sctp_tmit_chunk *chk;
        struct sctp_chunkhdr *ch;
        struct sctp_paramhdr *ph;
        int ret_code = 0;
        int num_param = 0;

        /* now it may be a reset or a reset-response */
        remaining_length = ntohs(ch_req->chunk_length) - sizeof(struct sctp_chunkhdr);

        /* setup for adding the response */
        sctp_alloc_a_chunk(stcb, chk);
        if (chk == NULL) {
                return (ret_code);
        }
        chk->copy_by_ref = 0;
        chk->rec.chunk_id.id = SCTP_STREAM_RESET;
        chk->rec.chunk_id.can_take_data = 0;
        chk->flags = 0;
        chk->asoc = &stcb->asoc;
        chk->no_fr_allowed = 0;
        chk->book_size = chk->send_size = sizeof(struct sctp_chunkhdr);
        chk->book_size_scale = 0;
        chk->data = sctp_get_mbuf_for_msg(MCLBYTES, 0, M_NOWAIT, 1, MT_DATA);
        if (chk->data == NULL) {
strres_nochunk:
                if (chk->data) {
                        sctp_m_freem(chk->data);
                        chk->data = NULL;
                }
                sctp_free_a_chunk(stcb, chk, SCTP_SO_NOT_LOCKED);
                return (ret_code);
        }
        SCTP_BUF_RESV_UF(chk->data, SCTP_MIN_OVERHEAD);

        /* setup chunk parameters */
        chk->sent = SCTP_DATAGRAM_UNSENT;
        chk->snd_count = 0;
        chk->whoTo = NULL;

        ch = mtod(chk->data, struct sctp_chunkhdr *);
        ch->chunk_type = SCTP_STREAM_RESET;
        ch->chunk_flags = 0;
        ch->chunk_length = htons(chk->send_size);
        SCTP_BUF_LEN(chk->data) = SCTP_SIZE32(chk->send_size);
        offset += sizeof(struct sctp_chunkhdr);
        while (remaining_length >= sizeof(struct sctp_paramhdr)) {
                ph = (struct sctp_paramhdr *)sctp_m_getptr(m, offset, sizeof(pstore), (uint8_t *) & pstore);
                if (ph == NULL) {
                        /* TSNH */
                        break;
                }
                param_len = ntohs(ph->param_length);
                if ((param_len > remaining_length) ||
                    (param_len < (sizeof(struct sctp_paramhdr) + sizeof(uint32_t)))) {
                        /* bad parameter length */
                        break;
                }
                ph = (struct sctp_paramhdr *)sctp_m_getptr(m, offset, min(param_len, sizeof(cstore)),
                    (uint8_t *) & cstore);
                if (ph == NULL) {
                        /* TSNH */
                        break;
                }
                ptype = ntohs(ph->param_type);
                num_param++;
                if (param_len > sizeof(cstore)) {
                        trunc = 1;
                } else {
                        trunc = 0;
                }
                if (num_param > SCTP_MAX_RESET_PARAMS) {
                        /* hit the max of parameters already sorry.. */
                        break;
                }
                if (ptype == SCTP_STR_RESET_OUT_REQUEST) {
                        struct sctp_stream_reset_out_request *req_out;

                        if (param_len < sizeof(struct sctp_stream_reset_out_request)) {
                                break;
                        }
                        req_out = (struct sctp_stream_reset_out_request *)ph;
                        num_req++;
                        if (stcb->asoc.stream_reset_outstanding) {
                                seq = ntohl(req_out->response_seq);
                                if (seq == stcb->asoc.str_reset_seq_out) {
                                        /* implicit ack */
                                        (void)sctp_handle_stream_reset_response(stcb, seq, SCTP_STREAM_RESET_RESULT_PERFORMED, NULL);
                                }
                        }
                        sctp_handle_str_reset_request_out(stcb, chk, req_out, trunc);
                } else if (ptype == SCTP_STR_RESET_ADD_OUT_STREAMS) {
                        struct sctp_stream_reset_add_strm *str_add;

                        if (param_len < sizeof(struct sctp_stream_reset_add_strm)) {
                                break;
                        }
                        str_add = (struct sctp_stream_reset_add_strm *)ph;
                        num_req++;
                        sctp_handle_str_reset_add_strm(stcb, chk, str_add);
                } else if (ptype == SCTP_STR_RESET_ADD_IN_STREAMS) {
                        struct sctp_stream_reset_add_strm *str_add;

                        if (param_len < sizeof(struct sctp_stream_reset_add_strm)) {
                                break;
                        }
                        str_add = (struct sctp_stream_reset_add_strm *)ph;
                        num_req++;
                        sctp_handle_str_reset_add_out_strm(stcb, chk, str_add);
                } else if (ptype == SCTP_STR_RESET_IN_REQUEST) {
                        struct sctp_stream_reset_in_request *req_in;

                        num_req++;
                        req_in = (struct sctp_stream_reset_in_request *)ph;
                        sctp_handle_str_reset_request_in(stcb, chk, req_in, trunc);
                } else if (ptype == SCTP_STR_RESET_TSN_REQUEST) {
                        struct sctp_stream_reset_tsn_request *req_tsn;

                        num_req++;
                        req_tsn = (struct sctp_stream_reset_tsn_request *)ph;
                        if (sctp_handle_str_reset_request_tsn(stcb, chk, req_tsn)) {
                                ret_code = 1;
                                goto strres_nochunk;
                        }
                        /* no more */
                        break;
                } else if (ptype == SCTP_STR_RESET_RESPONSE) {
                        struct sctp_stream_reset_response *resp;
                        uint32_t result;

                        if (param_len < sizeof(struct sctp_stream_reset_response)) {
                                break;
                        }
                        resp = (struct sctp_stream_reset_response *)ph;
                        seq = ntohl(resp->response_seq);
                        result = ntohl(resp->result);
                        if (sctp_handle_stream_reset_response(stcb, seq, result, resp)) {
                                ret_code = 1;
                                goto strres_nochunk;
                        }
                } else {
                        break;
                }
                offset += SCTP_SIZE32(param_len);
                if (remaining_length >= SCTP_SIZE32(param_len)) {
                        remaining_length -= SCTP_SIZE32(param_len);
                } else {
                        remaining_length = 0;
                }
        }
        if (num_req == 0) {
                /* we have no response free the stuff */
                goto strres_nochunk;
        }
        /* ok we have a chunk to link in */
        TAILQ_INSERT_TAIL(&stcb->asoc.control_send_queue,
            chk,
            sctp_next);
        stcb->asoc.ctrl_queue_cnt++;
        return (ret_code);
}

/*
 * Handle a router or endpoints report of a packet loss, there are two ways
 * to handle this, either we get the whole packet and must disect it
 * ourselves (possibly with truncation and or corruption) or it is a summary
 * from a middle box that did the disectting for us.
 */
static void
sctp_handle_packet_dropped(struct sctp_pktdrop_chunk *cp,
    struct sctp_tcb *stcb, struct sctp_nets *net, uint32_t limit)
{
        uint32_t bottle_bw, on_queue;
        uint16_t trunc_len;
        unsigned int chlen;
        unsigned int at;
        struct sctp_chunk_desc desc;
        struct sctp_chunkhdr *ch;

        chlen = ntohs(cp->ch.chunk_length);
        chlen -= sizeof(struct sctp_pktdrop_chunk);
        /* XXX possible chlen underflow */
        if (chlen == 0) {
                ch = NULL;
                if (cp->ch.chunk_flags & SCTP_FROM_MIDDLE_BOX)
                        SCTP_STAT_INCR(sctps_pdrpbwrpt);
        } else {
                ch = (struct sctp_chunkhdr *)(cp->data + sizeof(struct sctphdr));
                chlen -= sizeof(struct sctphdr);
                /* XXX possible chlen underflow */
                memset(&desc, 0, sizeof(desc));
        }
        trunc_len = (uint16_t) ntohs(cp->trunc_len);
        if (trunc_len > limit) {
                trunc_len = limit;
        }
        /* now the chunks themselves */
        while ((ch != NULL) && (chlen >= sizeof(struct sctp_chunkhdr))) {
                desc.chunk_type = ch->chunk_type;
                /* get amount we need to move */
                at = ntohs(ch->chunk_length);
                if (at < sizeof(struct sctp_chunkhdr)) {
                        /* corrupt chunk, maybe at the end? */
                        SCTP_STAT_INCR(sctps_pdrpcrupt);
                        break;
                }
                if (trunc_len == 0) {
                        /* we are supposed to have all of it */
                        if (at > chlen) {
                                /* corrupt skip it */
                                SCTP_STAT_INCR(sctps_pdrpcrupt);
                                break;
                        }
                } else {
                        /* is there enough of it left ? */
                        if (desc.chunk_type == SCTP_DATA) {
                                if (chlen < (sizeof(struct sctp_data_chunk) +
                                    sizeof(desc.data_bytes))) {
                                        break;
                                }
                        } else {
                                if (chlen < sizeof(struct sctp_chunkhdr)) {
                                        break;
                                }
                        }
                }
                if (desc.chunk_type == SCTP_DATA) {
                        /* can we get out the tsn? */
                        if ((cp->ch.chunk_flags & SCTP_FROM_MIDDLE_BOX))
                                SCTP_STAT_INCR(sctps_pdrpmbda);

                        if (chlen >= (sizeof(struct sctp_data_chunk) + sizeof(uint32_t))) {
                                /* yep */
                                struct sctp_data_chunk *dcp;
                                uint8_t *ddp;
                                unsigned int iii;

                                dcp = (struct sctp_data_chunk *)ch;
                                ddp = (uint8_t *) (dcp + 1);
                                for (iii = 0; iii < sizeof(desc.data_bytes); iii++) {
                                        desc.data_bytes[iii] = ddp[iii];
                                }
                                desc.tsn_ifany = dcp->dp.tsn;
                        } else {
                                /* nope we are done. */
                                SCTP_STAT_INCR(sctps_pdrpnedat);
                                break;
                        }
                } else {
                        if ((cp->ch.chunk_flags & SCTP_FROM_MIDDLE_BOX))
                                SCTP_STAT_INCR(sctps_pdrpmbct);
                }

                if (process_chunk_drop(stcb, &desc, net, cp->ch.chunk_flags)) {
                        SCTP_STAT_INCR(sctps_pdrppdbrk);
                        break;
                }
                if (SCTP_SIZE32(at) > chlen) {
                        break;
                }
                chlen -= SCTP_SIZE32(at);
                if (chlen < sizeof(struct sctp_chunkhdr)) {
                        /* done, none left */
                        break;
                }
                ch = (struct sctp_chunkhdr *)((caddr_t)ch + SCTP_SIZE32(at));
        }
        /* Now update any rwnd --- possibly */
        if ((cp->ch.chunk_flags & SCTP_FROM_MIDDLE_BOX) == 0) {
                /* From a peer, we get a rwnd report */
                uint32_t a_rwnd;

                SCTP_STAT_INCR(sctps_pdrpfehos);

                bottle_bw = ntohl(cp->bottle_bw);
                on_queue = ntohl(cp->current_onq);
                if (bottle_bw && on_queue) {
                        /* a rwnd report is in here */
                        if (bottle_bw > on_queue)
                                a_rwnd = bottle_bw - on_queue;
                        else
                                a_rwnd = 0;

                        if (a_rwnd == 0)
                                stcb->asoc.peers_rwnd = 0;
                        else {
                                if (a_rwnd > stcb->asoc.total_flight) {
                                        stcb->asoc.peers_rwnd =
                                            a_rwnd - stcb->asoc.total_flight;
                                } else {
                                        stcb->asoc.peers_rwnd = 0;
                                }
                                if (stcb->asoc.peers_rwnd <
                                    stcb->sctp_ep->sctp_ep.sctp_sws_sender) {
                                        /* SWS sender side engages */
                                        stcb->asoc.peers_rwnd = 0;
                                }
                        }
                }
        } else {
                SCTP_STAT_INCR(sctps_pdrpfmbox);
        }

        /* now middle boxes in sat networks get a cwnd bump */
        if ((cp->ch.chunk_flags & SCTP_FROM_MIDDLE_BOX) &&
            (stcb->asoc.sat_t3_loss_recovery == 0) &&
            (stcb->asoc.sat_network)) {
                /*
                 * This is debateable but for sat networks it makes sense
                 * Note if a T3 timer has went off, we will prohibit any
                 * changes to cwnd until we exit the t3 loss recovery.
                 */
                stcb->asoc.cc_functions.sctp_cwnd_update_after_packet_dropped(stcb,
                    net, cp, &bottle_bw, &on_queue);
        }
}

/*
 * handles all control chunks in a packet inputs: - m: mbuf chain, assumed to
 * still contain IP/SCTP header - stcb: is the tcb found for this packet -
 * offset: offset into the mbuf chain to first chunkhdr - length: is the
 * length of the complete packet outputs: - length: modified to remaining
 * length after control processing - netp: modified to new sctp_nets after
 * cookie-echo processing - return NULL to discard the packet (ie. no asoc,
 * bad packet,...) otherwise return the tcb for this packet
 */
#ifdef __GNUC__
__attribute__((noinline))
#endif
        static struct sctp_tcb *
                 sctp_process_control(struct mbuf *m, int iphlen, int *offset, int length,
             struct sockaddr *src, struct sockaddr *dst,
             struct sctphdr *sh, struct sctp_chunkhdr *ch, struct sctp_inpcb *inp,
             struct sctp_tcb *stcb, struct sctp_nets **netp, int *fwd_tsn_seen,
             uint8_t mflowtype, uint32_t mflowid, uint16_t fibnum,
             uint32_t vrf_id, uint16_t port)
{
        struct sctp_association *asoc;
        struct mbuf *op_err;
        char msg[SCTP_DIAG_INFO_LEN];
        uint32_t vtag_in;
        int num_chunks = 0;     /* number of control chunks processed */
        uint32_t chk_length;
        int ret;
        int abort_no_unlock = 0;
        int ecne_seen = 0;

        /*
         * How big should this be, and should it be alloc'd? Lets try the
         * d-mtu-ceiling for now (2k) and that should hopefully work ...
         * until we get into jumbo grams and such..
         */
        uint8_t chunk_buf[SCTP_CHUNK_BUFFER_SIZE];
        struct sctp_tcb *locked_tcb = stcb;
        int got_auth = 0;
        uint32_t auth_offset = 0, auth_len = 0;
        int auth_skipped = 0;
        int asconf_cnt = 0;

#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
        struct socket *so;

#endif

        SCTPDBG(SCTP_DEBUG_INPUT1, "sctp_process_control: iphlen=%u, offset=%u, length=%u stcb:%p\n",
            iphlen, *offset, length, (void *)stcb);

        /* validate chunk header length... */
        if (ntohs(ch->chunk_length) < sizeof(*ch)) {
                SCTPDBG(SCTP_DEBUG_INPUT1, "Invalid header length %d\n",
                    ntohs(ch->chunk_length));
                if (locked_tcb) {
                        SCTP_TCB_UNLOCK(locked_tcb);
                }
                return (NULL);
        }
        /*
         * validate the verification tag
         */
        vtag_in = ntohl(sh->v_tag);

        if (locked_tcb) {
                SCTP_TCB_LOCK_ASSERT(locked_tcb);
        }
        if (ch->chunk_type == SCTP_INITIATION) {
                SCTPDBG(SCTP_DEBUG_INPUT1, "Its an INIT of len:%d vtag:%x\n",
                    ntohs(ch->chunk_length), vtag_in);
                if (vtag_in != 0) {
                        /* protocol error- silently discard... */
                        SCTP_STAT_INCR(sctps_badvtag);
                        if (locked_tcb) {
                                SCTP_TCB_UNLOCK(locked_tcb);
                        }
                        return (NULL);
                }
        } else if (ch->chunk_type != SCTP_COOKIE_ECHO) {
                /*
                 * If there is no stcb, skip the AUTH chunk and process
                 * later after a stcb is found (to validate the lookup was
                 * valid.
                 */
                if ((ch->chunk_type == SCTP_AUTHENTICATION) &&
                    (stcb == NULL) &&
                    (inp->auth_supported == 1)) {
                        /* save this chunk for later processing */
                        auth_skipped = 1;
                        auth_offset = *offset;
                        auth_len = ntohs(ch->chunk_length);

                        /* (temporarily) move past this chunk */
                        *offset += SCTP_SIZE32(auth_len);
                        if (*offset >= length) {
                                /* no more data left in the mbuf chain */
                                *offset = length;
                                if (locked_tcb) {
                                        SCTP_TCB_UNLOCK(locked_tcb);
                                }
                                return (NULL);
                        }
                        ch = (struct sctp_chunkhdr *)sctp_m_getptr(m, *offset,
                            sizeof(struct sctp_chunkhdr), chunk_buf);
                }
                if (ch == NULL) {
                        /* Help */
                        *offset = length;
                        if (locked_tcb) {
                                SCTP_TCB_UNLOCK(locked_tcb);
                        }
                        return (NULL);
                }
                if (ch->chunk_type == SCTP_COOKIE_ECHO) {
                        goto process_control_chunks;
                }
                /*
                 * first check if it's an ASCONF with an unknown src addr we
                 * need to look inside to find the association
                 */
                if (ch->chunk_type == SCTP_ASCONF && stcb == NULL) {
                        struct sctp_chunkhdr *asconf_ch = ch;
                        uint32_t asconf_offset = 0, asconf_len = 0;

                        /* inp's refcount may be reduced */
                        SCTP_INP_INCR_REF(inp);

                        asconf_offset = *offset;
                        do {
                                asconf_len = ntohs(asconf_ch->chunk_length);
                                if (asconf_len < sizeof(struct sctp_asconf_paramhdr))
                                        break;
                                stcb = sctp_findassociation_ep_asconf(m,
                                    *offset,
                                    dst,
                                    sh, &inp, netp, vrf_id);
                                if (stcb != NULL)
                                        break;
                                asconf_offset += SCTP_SIZE32(asconf_len);
                                asconf_ch = (struct sctp_chunkhdr *)sctp_m_getptr(m, asconf_offset,
                                    sizeof(struct sctp_chunkhdr), chunk_buf);
                        } while (asconf_ch != NULL && asconf_ch->chunk_type == SCTP_ASCONF);
                        if (stcb == NULL) {
                                /*
                                 * reduce inp's refcount if not reduced in
                                 * sctp_findassociation_ep_asconf().
                                 */
                                SCTP_INP_DECR_REF(inp);
                        } else {
                                locked_tcb = stcb;
                        }

                        /* now go back and verify any auth chunk to be sure */
                        if (auth_skipped && (stcb != NULL)) {
                                struct sctp_auth_chunk *auth;

                                auth = (struct sctp_auth_chunk *)
                                    sctp_m_getptr(m, auth_offset,
                                    auth_len, chunk_buf);
                                got_auth = 1;
                                auth_skipped = 0;
                                if ((auth == NULL) || sctp_handle_auth(stcb, auth, m,
                                    auth_offset)) {
                                        /* auth HMAC failed so dump it */
                                        *offset = length;
                                        if (locked_tcb) {
                                                SCTP_TCB_UNLOCK(locked_tcb);
                                        }
                                        return (NULL);
                                } else {
                                        /* remaining chunks are HMAC checked */
                                        stcb->asoc.authenticated = 1;
                                }
                        }
                }
                if (stcb == NULL) {
                        snprintf(msg, sizeof(msg), "OOTB, %s:%d at %s", __FILE__, __LINE__, __func__);
                        op_err = sctp_generate_cause(SCTP_BASE_SYSCTL(sctp_diag_info_code),
                            msg);
                        /* no association, so it's out of the blue... */
                        sctp_handle_ootb(m, iphlen, *offset, src, dst, sh, inp, op_err,
                            mflowtype, mflowid, inp->fibnum,
                            vrf_id, port);
                        *offset = length;
                        if (locked_tcb) {
                                SCTP_TCB_UNLOCK(locked_tcb);
                        }
                        return (NULL);
                }
                asoc = &stcb->asoc;
                /* ABORT and SHUTDOWN can use either v_tag... */
                if ((ch->chunk_type == SCTP_ABORT_ASSOCIATION) ||
                    (ch->chunk_type == SCTP_SHUTDOWN_COMPLETE) ||
                    (ch->chunk_type == SCTP_PACKET_DROPPED)) {
                        /* Take the T-bit always into account. */
                        if ((((ch->chunk_flags & SCTP_HAD_NO_TCB) == 0) &&
                            (vtag_in == asoc->my_vtag)) ||
                            (((ch->chunk_flags & SCTP_HAD_NO_TCB) == SCTP_HAD_NO_TCB) &&
                            (vtag_in == asoc->peer_vtag))) {
                                /* this is valid */
                        } else {
                                /* drop this packet... */
                                SCTP_STAT_INCR(sctps_badvtag);
                                if (locked_tcb) {
                                        SCTP_TCB_UNLOCK(locked_tcb);
                                }
                                return (NULL);
                        }
                } else if (ch->chunk_type == SCTP_SHUTDOWN_ACK) {
                        if (vtag_in != asoc->my_vtag) {
                                /*
                                 * this could be a stale SHUTDOWN-ACK or the
                                 * peer never got the SHUTDOWN-COMPLETE and
                                 * is still hung; we have started a new asoc
                                 * but it won't complete until the shutdown
                                 * is completed
                                 */
                                if (locked_tcb) {
                                        SCTP_TCB_UNLOCK(locked_tcb);
                                }
                                snprintf(msg, sizeof(msg), "OOTB, %s:%d at %s", __FILE__, __LINE__, __func__);
                                op_err = sctp_generate_cause(SCTP_BASE_SYSCTL(sctp_diag_info_code),
                                    msg);
                                sctp_handle_ootb(m, iphlen, *offset, src, dst,
                                    sh, inp, op_err,
                                    mflowtype, mflowid, fibnum,
                                    vrf_id, port);
                                return (NULL);
                        }
                } else {
                        /* for all other chunks, vtag must match */
                        if (vtag_in != asoc->my_vtag) {
                                /* invalid vtag... */
                                SCTPDBG(SCTP_DEBUG_INPUT3,
                                    "invalid vtag: %xh, expect %xh\n",
                                    vtag_in, asoc->my_vtag);
                                SCTP_STAT_INCR(sctps_badvtag);
                                if (locked_tcb) {
                                        SCTP_TCB_UNLOCK(locked_tcb);
                                }
                                *offset = length;
                                return (NULL);
                        }
                }
        }                       /* end if !SCTP_COOKIE_ECHO */
        /*
         * process all control chunks...
         */
        if (((ch->chunk_type == SCTP_SELECTIVE_ACK) ||
            (ch->chunk_type == SCTP_NR_SELECTIVE_ACK) ||
            (ch->chunk_type == SCTP_HEARTBEAT_REQUEST)) &&
            (SCTP_GET_STATE(&stcb->asoc) == SCTP_STATE_COOKIE_ECHOED)) {
                /* implied cookie-ack.. we must have lost the ack */
                if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_THRESHOLD_LOGGING) {
                        sctp_misc_ints(SCTP_THRESHOLD_CLEAR,
                            stcb->asoc.overall_error_count,
                            0,
                            SCTP_FROM_SCTP_INPUT,
                            __LINE__);
                }
                stcb->asoc.overall_error_count = 0;
                sctp_handle_cookie_ack((struct sctp_cookie_ack_chunk *)ch, stcb,
                    *netp);
        }
process_control_chunks:
        while (IS_SCTP_CONTROL(ch)) {
                /* validate chunk length */
                chk_length = ntohs(ch->chunk_length);
                SCTPDBG(SCTP_DEBUG_INPUT2, "sctp_process_control: processing a chunk type=%u, len=%u\n",
                    ch->chunk_type, chk_length);
                SCTP_LTRACE_CHK(inp, stcb, ch->chunk_type, chk_length);
                if (chk_length < sizeof(*ch) ||
                    (*offset + (int)chk_length) > length) {
                        *offset = length;
                        if (locked_tcb) {
                                SCTP_TCB_UNLOCK(locked_tcb);
                        }
                        return (NULL);
                }
                SCTP_STAT_INCR_COUNTER64(sctps_incontrolchunks);
                /*
                 * INIT-ACK only gets the init ack "header" portion only
                 * because we don't have to process the peer's COOKIE. All
                 * others get a complete chunk.
                 */
                if ((ch->chunk_type == SCTP_INITIATION_ACK) ||
                    (ch->chunk_type == SCTP_INITIATION)) {
                        /* get an init-ack chunk */
                        ch = (struct sctp_chunkhdr *)sctp_m_getptr(m, *offset,
                            sizeof(struct sctp_init_ack_chunk), chunk_buf);
                        if (ch == NULL) {
                                *offset = length;
                                if (locked_tcb) {
                                        SCTP_TCB_UNLOCK(locked_tcb);
                                }
                                return (NULL);
                        }
                } else {
                        /* For cookies and all other chunks. */
                        if (chk_length > sizeof(chunk_buf)) {
                                /*
                                 * use just the size of the chunk buffer so
                                 * the front part of our chunks fit in
                                 * contiguous space up to the chunk buffer
                                 * size (508 bytes). For chunks that need to
                                 * get more than that they must use the
                                 * sctp_m_getptr() function or other means
                                 * (e.g. know how to parse mbuf chains).
                                 * Cookies do this already.
                                 */
                                ch = (struct sctp_chunkhdr *)sctp_m_getptr(m, *offset,
                                    (sizeof(chunk_buf) - 4),
                                    chunk_buf);
                                if (ch == NULL) {
                                        *offset = length;
                                        if (locked_tcb) {
                                                SCTP_TCB_UNLOCK(locked_tcb);
                                        }
                                        return (NULL);
                                }
                        } else {
                                /* We can fit it all */
                                ch = (struct sctp_chunkhdr *)sctp_m_getptr(m, *offset,
                                    chk_length, chunk_buf);
                                if (ch == NULL) {
                                        SCTP_PRINTF("sctp_process_control: Can't get the all data....\n");
                                        *offset = length;
                                        if (locked_tcb) {
                                                SCTP_TCB_UNLOCK(locked_tcb);
                                        }
                                        return (NULL);
                                }
                        }
                }
                num_chunks++;
                /* Save off the last place we got a control from */
                if (stcb != NULL) {
                        if (((netp != NULL) && (*netp != NULL)) || (ch->chunk_type == SCTP_ASCONF)) {
                                /*
                                 * allow last_control to be NULL if
                                 * ASCONF... ASCONF processing will find the
                                 * right net later
                                 */
                                if ((netp != NULL) && (*netp != NULL))
                                        stcb->asoc.last_control_chunk_from = *netp;
                        }
                }
#ifdef SCTP_AUDITING_ENABLED
                sctp_audit_log(0xB0, ch->chunk_type);
#endif

                /* check to see if this chunk required auth, but isn't */
                if ((stcb != NULL) &&
                    (stcb->asoc.auth_supported == 1) &&
                    sctp_auth_is_required_chunk(ch->chunk_type, stcb->asoc.local_auth_chunks) &&
                    !stcb->asoc.authenticated) {
                        /* "silently" ignore */
                        SCTP_STAT_INCR(sctps_recvauthmissing);
                        goto next_chunk;
                }
                switch (ch->chunk_type) {
                case SCTP_INITIATION:
                        SCTPDBG(SCTP_DEBUG_INPUT3, "SCTP_INIT\n");
                        /* The INIT chunk must be the only chunk. */
                        if ((num_chunks > 1) ||
                            (length - *offset > (int)SCTP_SIZE32(chk_length))) {
                                /* RFC 4960 requires that no ABORT is sent */
                                *offset = length;
                                if (locked_tcb) {
                                        SCTP_TCB_UNLOCK(locked_tcb);
                                }
                                return (NULL);
                        }
                        /* Honor our resource limit. */
                        if (chk_length > SCTP_LARGEST_INIT_ACCEPTED) {
                                op_err = sctp_generate_cause(SCTP_CAUSE_OUT_OF_RESC, "");
                                sctp_abort_association(inp, stcb, m, iphlen,
                                    src, dst, sh, op_err,
                                    mflowtype, mflowid,
                                    vrf_id, port);
                                *offset = length;
                                return (NULL);
                        }
                        sctp_handle_init(m, iphlen, *offset, src, dst, sh,
                            (struct sctp_init_chunk *)ch, inp,
                            stcb, *netp, &abort_no_unlock,
                            mflowtype, mflowid,
                            vrf_id, port);
                        *offset = length;
                        if ((!abort_no_unlock) && (locked_tcb)) {
                                SCTP_TCB_UNLOCK(locked_tcb);
                        }
                        return (NULL);
                        break;
                case SCTP_PAD_CHUNK:
                        break;
                case SCTP_INITIATION_ACK:
                        SCTPDBG(SCTP_DEBUG_INPUT3, "SCTP_INIT-ACK\n");
                        if (inp->sctp_flags & SCTP_PCB_FLAGS_SOCKET_GONE) {
                                /* We are not interested anymore */
                                if ((stcb) && (stcb->asoc.total_output_queue_size)) {
                                        ;
                                } else {
                                        if ((locked_tcb != NULL) && (locked_tcb != stcb)) {
                                                /* Very unlikely */
                                                SCTP_TCB_UNLOCK(locked_tcb);
                                        }
                                        *offset = length;
                                        if (stcb) {
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                                                so = SCTP_INP_SO(inp);
                                                atomic_add_int(&stcb->asoc.refcnt, 1);
                                                SCTP_TCB_UNLOCK(stcb);
                                                SCTP_SOCKET_LOCK(so, 1);
                                                SCTP_TCB_LOCK(stcb);
                                                atomic_subtract_int(&stcb->asoc.refcnt, 1);
#endif
                                                (void)sctp_free_assoc(inp, stcb, SCTP_NORMAL_PROC,
                                                    SCTP_FROM_SCTP_INPUT + SCTP_LOC_29);
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                                                SCTP_SOCKET_UNLOCK(so, 1);
#endif
                                        }
                                        return (NULL);
                                }
                        }
                        /* The INIT-ACK chunk must be the only chunk. */
                        if ((num_chunks > 1) ||
                            (length - *offset > (int)SCTP_SIZE32(chk_length))) {
                                *offset = length;
                                if (locked_tcb) {
                                        SCTP_TCB_UNLOCK(locked_tcb);
                                }
                                return (NULL);
                        }
                        if ((netp) && (*netp)) {
                                ret = sctp_handle_init_ack(m, iphlen, *offset,
                                    src, dst, sh,
                                    (struct sctp_init_ack_chunk *)ch,
                                    stcb, *netp,
                                    &abort_no_unlock,
                                    mflowtype, mflowid,
                                    vrf_id);
                        } else {
                                ret = -1;
                        }
                        *offset = length;
                        if (abort_no_unlock) {
                                return (NULL);
                        }
                        /*
                         * Special case, I must call the output routine to
                         * get the cookie echoed
                         */
                        if ((stcb != NULL) && (ret == 0)) {
                                sctp_chunk_output(stcb->sctp_ep, stcb, SCTP_OUTPUT_FROM_CONTROL_PROC, SCTP_SO_NOT_LOCKED);
                        }
                        if (locked_tcb) {
                                SCTP_TCB_UNLOCK(locked_tcb);
                        }
                        return (NULL);
                        break;
                case SCTP_SELECTIVE_ACK:
                        {
                                struct sctp_sack_chunk *sack;
                                int abort_now = 0;
                                uint32_t a_rwnd, cum_ack;
                                uint16_t num_seg, num_dup;
                                uint8_t flags;
                                int offset_seg, offset_dup;

                                SCTPDBG(SCTP_DEBUG_INPUT3, "SCTP_SACK\n");
                                SCTP_STAT_INCR(sctps_recvsacks);
                                if (stcb == NULL) {
                                        SCTPDBG(SCTP_DEBUG_INDATA1, "No stcb when processing SACK chunk\n");
                                        break;
                                }
                                if (chk_length < sizeof(struct sctp_sack_chunk)) {
                                        SCTPDBG(SCTP_DEBUG_INDATA1, "Bad size on SACK chunk, too small\n");
                                        break;
                                }
                                if (SCTP_GET_STATE(&stcb->asoc) == SCTP_STATE_SHUTDOWN_ACK_SENT) {
                                        /*-
                                         * If we have sent a shutdown-ack, we will pay no
                                         * attention to a sack sent in to us since
                                         * we don't care anymore.
                                         */
                                        break;
                                }
                                sack = (struct sctp_sack_chunk *)ch;
                                flags = ch->chunk_flags;
                                cum_ack = ntohl(sack->sack.cum_tsn_ack);
                                num_seg = ntohs(sack->sack.num_gap_ack_blks);
                                num_dup = ntohs(sack->sack.num_dup_tsns);
                                a_rwnd = (uint32_t) ntohl(sack->sack.a_rwnd);
                                if (sizeof(struct sctp_sack_chunk) +
                                    num_seg * sizeof(struct sctp_gap_ack_block) +
                                    num_dup * sizeof(uint32_t) != chk_length) {
                                        SCTPDBG(SCTP_DEBUG_INDATA1, "Bad size of SACK chunk\n");
                                        break;
                                }
                                offset_seg = *offset + sizeof(struct sctp_sack_chunk);
                                offset_dup = offset_seg + num_seg * sizeof(struct sctp_gap_ack_block);
                                SCTPDBG(SCTP_DEBUG_INPUT3, "SCTP_SACK process cum_ack:%x num_seg:%d a_rwnd:%d\n",
                                    cum_ack, num_seg, a_rwnd);
                                stcb->asoc.seen_a_sack_this_pkt = 1;
                                if ((stcb->asoc.pr_sctp_cnt == 0) &&
                                    (num_seg == 0) &&
                                    SCTP_TSN_GE(cum_ack, stcb->asoc.last_acked_seq) &&
                                    (stcb->asoc.saw_sack_with_frags == 0) &&
                                    (stcb->asoc.saw_sack_with_nr_frags == 0) &&
                                    (!TAILQ_EMPTY(&stcb->asoc.sent_queue))
                                    ) {
                                        /*
                                         * We have a SIMPLE sack having no
                                         * prior segments and data on sent
                                         * queue to be acked.. Use the
                                         * faster path sack processing. We
                                         * also allow window update sacks
                                         * with no missing segments to go
                                         * this way too.
                                         */
                                        sctp_express_handle_sack(stcb, cum_ack, a_rwnd, &abort_now, ecne_seen);
                                } else {
                                        if (netp && *netp)
                                                sctp_handle_sack(m, offset_seg, offset_dup, stcb,
                                                    num_seg, 0, num_dup, &abort_now, flags,
                                                    cum_ack, a_rwnd, ecne_seen);
                                }
                                if (abort_now) {
                                        /* ABORT signal from sack processing */
                                        *offset = length;
                                        return (NULL);
                                }
                                if (TAILQ_EMPTY(&stcb->asoc.send_queue) &&
                                    TAILQ_EMPTY(&stcb->asoc.sent_queue) &&
                                    (stcb->asoc.stream_queue_cnt == 0)) {
                                        sctp_ulp_notify(SCTP_NOTIFY_SENDER_DRY, stcb, 0, NULL, SCTP_SO_NOT_LOCKED);
                                }
                        }
                        break;
                        /*
                         * EY - nr_sack:  If the received chunk is an
                         * nr_sack chunk
                         */
                case SCTP_NR_SELECTIVE_ACK:
                        {
                                struct sctp_nr_sack_chunk *nr_sack;
                                int abort_now = 0;
                                uint32_t a_rwnd, cum_ack;
                                uint16_t num_seg, num_nr_seg, num_dup;
                                uint8_t flags;
                                int offset_seg, offset_dup;

                                SCTPDBG(SCTP_DEBUG_INPUT3, "SCTP_NR_SACK\n");
                                SCTP_STAT_INCR(sctps_recvsacks);
                                if (stcb == NULL) {
                                        SCTPDBG(SCTP_DEBUG_INDATA1, "No stcb when processing NR-SACK chunk\n");
                                        break;
                                }
                                if (stcb->asoc.nrsack_supported == 0) {
                                        goto unknown_chunk;
                                }
                                if (chk_length < sizeof(struct sctp_nr_sack_chunk)) {
                                        SCTPDBG(SCTP_DEBUG_INDATA1, "Bad size on NR-SACK chunk, too small\n");
                                        break;
                                }
                                if (SCTP_GET_STATE(&stcb->asoc) == SCTP_STATE_SHUTDOWN_ACK_SENT) {
                                        /*-
                                         * If we have sent a shutdown-ack, we will pay no
                                         * attention to a sack sent in to us since
                                         * we don't care anymore.
                                         */
                                        break;
                                }
                                nr_sack = (struct sctp_nr_sack_chunk *)ch;
                                flags = ch->chunk_flags;
                                cum_ack = ntohl(nr_sack->nr_sack.cum_tsn_ack);
                                num_seg = ntohs(nr_sack->nr_sack.num_gap_ack_blks);
                                num_nr_seg = ntohs(nr_sack->nr_sack.num_nr_gap_ack_blks);
                                num_dup = ntohs(nr_sack->nr_sack.num_dup_tsns);
                                a_rwnd = (uint32_t) ntohl(nr_sack->nr_sack.a_rwnd);
                                if (sizeof(struct sctp_nr_sack_chunk) +
                                    (num_seg + num_nr_seg) * sizeof(struct sctp_gap_ack_block) +
                                    num_dup * sizeof(uint32_t) != chk_length) {
                                        SCTPDBG(SCTP_DEBUG_INDATA1, "Bad size of NR_SACK chunk\n");
                                        break;
                                }
                                offset_seg = *offset + sizeof(struct sctp_nr_sack_chunk);
                                offset_dup = offset_seg + num_seg * sizeof(struct sctp_gap_ack_block);
                                SCTPDBG(SCTP_DEBUG_INPUT3, "SCTP_NR_SACK process cum_ack:%x num_seg:%d a_rwnd:%d\n",
                                    cum_ack, num_seg, a_rwnd);
                                stcb->asoc.seen_a_sack_this_pkt = 1;
                                if ((stcb->asoc.pr_sctp_cnt == 0) &&
                                    (num_seg == 0) && (num_nr_seg == 0) &&
                                    SCTP_TSN_GE(cum_ack, stcb->asoc.last_acked_seq) &&
                                    (stcb->asoc.saw_sack_with_frags == 0) &&
                                    (stcb->asoc.saw_sack_with_nr_frags == 0) &&
                                    (!TAILQ_EMPTY(&stcb->asoc.sent_queue))) {
                                        /*
                                         * We have a SIMPLE sack having no
                                         * prior segments and data on sent
                                         * queue to be acked. Use the faster
                                         * path sack processing. We also
                                         * allow window update sacks with no
                                         * missing segments to go this way
                                         * too.
                                         */
                                        sctp_express_handle_sack(stcb, cum_ack, a_rwnd,
                                            &abort_now, ecne_seen);
                                } else {
                                        if (netp && *netp)
                                                sctp_handle_sack(m, offset_seg, offset_dup, stcb,
                                                    num_seg, num_nr_seg, num_dup, &abort_now, flags,
                                                    cum_ack, a_rwnd, ecne_seen);
                                }
                                if (abort_now) {
                                        /* ABORT signal from sack processing */
                                        *offset = length;
                                        return (NULL);
                                }
                                if (TAILQ_EMPTY(&stcb->asoc.send_queue) &&
                                    TAILQ_EMPTY(&stcb->asoc.sent_queue) &&
                                    (stcb->asoc.stream_queue_cnt == 0)) {
                                        sctp_ulp_notify(SCTP_NOTIFY_SENDER_DRY, stcb, 0, NULL, SCTP_SO_NOT_LOCKED);
                                }
                        }
                        break;

                case SCTP_HEARTBEAT_REQUEST:
                        SCTPDBG(SCTP_DEBUG_INPUT3, "SCTP_HEARTBEAT\n");
                        if ((stcb) && netp && *netp) {
                                SCTP_STAT_INCR(sctps_recvheartbeat);
                                sctp_send_heartbeat_ack(stcb, m, *offset,
                                    chk_length, *netp);

                                /* He's alive so give him credit */
                                if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_THRESHOLD_LOGGING) {
                                        sctp_misc_ints(SCTP_THRESHOLD_CLEAR,
                                            stcb->asoc.overall_error_count,
                                            0,
                                            SCTP_FROM_SCTP_INPUT,
                                            __LINE__);
                                }
                                stcb->asoc.overall_error_count = 0;
                        }
                        break;
                case SCTP_HEARTBEAT_ACK:
                        SCTPDBG(SCTP_DEBUG_INPUT3, "SCTP_HEARTBEAT-ACK\n");
                        if ((stcb == NULL) || (chk_length != sizeof(struct sctp_heartbeat_chunk))) {
                                /* Its not ours */
                                *offset = length;
                                if (locked_tcb) {
                                        SCTP_TCB_UNLOCK(locked_tcb);
                                }
                                return (NULL);
                        }
                        /* He's alive so give him credit */
                        if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_THRESHOLD_LOGGING) {
                                sctp_misc_ints(SCTP_THRESHOLD_CLEAR,
                                    stcb->asoc.overall_error_count,
                                    0,
                                    SCTP_FROM_SCTP_INPUT,
                                    __LINE__);
                        }
                        stcb->asoc.overall_error_count = 0;
                        SCTP_STAT_INCR(sctps_recvheartbeatack);
                        if (netp && *netp)
                                sctp_handle_heartbeat_ack((struct sctp_heartbeat_chunk *)ch,
                                    stcb, *netp);
                        break;
                case SCTP_ABORT_ASSOCIATION:
                        SCTPDBG(SCTP_DEBUG_INPUT3, "SCTP_ABORT, stcb %p\n",
                            (void *)stcb);
                        if ((stcb) && netp && *netp)
                                sctp_handle_abort((struct sctp_abort_chunk *)ch,
                                    stcb, *netp);
                        *offset = length;
                        return (NULL);
                        break;
                case SCTP_SHUTDOWN:
                        SCTPDBG(SCTP_DEBUG_INPUT3, "SCTP_SHUTDOWN, stcb %p\n",
                            (void *)stcb);
                        if ((stcb == NULL) || (chk_length != sizeof(struct sctp_shutdown_chunk))) {
                                *offset = length;
                                if (locked_tcb) {
                                        SCTP_TCB_UNLOCK(locked_tcb);
                                }
                                return (NULL);
                        }
                        if (netp && *netp) {
                                int abort_flag = 0;

                                sctp_handle_shutdown((struct sctp_shutdown_chunk *)ch,
                                    stcb, *netp, &abort_flag);
                                if (abort_flag) {
                                        *offset = length;
                                        return (NULL);
                                }
                        }
                        break;
                case SCTP_SHUTDOWN_ACK:
                        SCTPDBG(SCTP_DEBUG_INPUT3, "SCTP_SHUTDOWN-ACK, stcb %p\n", (void *)stcb);
                        if ((stcb) && (netp) && (*netp))
                                sctp_handle_shutdown_ack((struct sctp_shutdown_ack_chunk *)ch, stcb, *netp);
                        *offset = length;
                        return (NULL);
                        break;

                case SCTP_OPERATION_ERROR:
                        SCTPDBG(SCTP_DEBUG_INPUT3, "SCTP_OP-ERR\n");
                        if ((stcb) && netp && *netp && sctp_handle_error(ch, stcb, *netp) < 0) {
                                *offset = length;
                                return (NULL);
                        }
                        break;
                case SCTP_COOKIE_ECHO:
                        SCTPDBG(SCTP_DEBUG_INPUT3,
                            "SCTP_COOKIE-ECHO, stcb %p\n", (void *)stcb);
                        if ((stcb) && (stcb->asoc.total_output_queue_size)) {
                                ;
                        } else {
                                if (inp->sctp_flags & SCTP_PCB_FLAGS_SOCKET_GONE) {
                                        /* We are not interested anymore */
                        abend:
                                        if (stcb) {
                                                SCTP_TCB_UNLOCK(stcb);
                                        }
                                        *offset = length;
                                        return (NULL);
                                }
                        }
                        /*
                         * First are we accepting? We do this again here
                         * since it is possible that a previous endpoint WAS
                         * listening responded to a INIT-ACK and then
                         * closed. We opened and bound.. and are now no
                         * longer listening.
                         */

                        if ((stcb == NULL) && (inp->sctp_socket->so_qlen >= inp->sctp_socket->so_qlimit)) {
                                if ((inp->sctp_flags & SCTP_PCB_FLAGS_TCPTYPE) &&
                                    (SCTP_BASE_SYSCTL(sctp_abort_if_one_2_one_hits_limit))) {
                                        op_err = sctp_generate_cause(SCTP_CAUSE_OUT_OF_RESC, "");
                                        sctp_abort_association(inp, stcb, m, iphlen,
                                            src, dst, sh, op_err,
                                            mflowtype, mflowid,
                                            vrf_id, port);
                                }
                                *offset = length;
                                return (NULL);
                        } else {
                                struct mbuf *ret_buf;
                                struct sctp_inpcb *linp;

                                if (stcb) {
                                        linp = NULL;
                                } else {
                                        linp = inp;
                                }

                                if (linp) {
                                        SCTP_ASOC_CREATE_LOCK(linp);
                                        if ((inp->sctp_flags & SCTP_PCB_FLAGS_SOCKET_GONE) ||
                                            (inp->sctp_flags & SCTP_PCB_FLAGS_SOCKET_ALLGONE)) {
                                                SCTP_ASOC_CREATE_UNLOCK(linp);
                                                goto abend;
                                        }
                                }
                                if (netp) {
                                        ret_buf =
                                            sctp_handle_cookie_echo(m, iphlen,
                                            *offset,
                                            src, dst,
                                            sh,
                                            (struct sctp_cookie_echo_chunk *)ch,
                                            &inp, &stcb, netp,
                                            auth_skipped,
                                            auth_offset,
                                            auth_len,
                                            &locked_tcb,
                                            mflowtype,
                                            mflowid,
                                            vrf_id,
                                            port);
                                } else {
                                        ret_buf = NULL;
                                }
                                if (linp) {
                                        SCTP_ASOC_CREATE_UNLOCK(linp);
                                }
                                if (ret_buf == NULL) {
                                        if (locked_tcb) {
                                                SCTP_TCB_UNLOCK(locked_tcb);
                                        }
                                        SCTPDBG(SCTP_DEBUG_INPUT3,
                                            "GAK, null buffer\n");
                                        *offset = length;
                                        return (NULL);
                                }
                                /* if AUTH skipped, see if it verified... */
                                if (auth_skipped) {
                                        got_auth = 1;
                                        auth_skipped = 0;
                                }
                                if (!TAILQ_EMPTY(&stcb->asoc.sent_queue)) {
                                        /*
                                         * Restart the timer if we have
                                         * pending data
                                         */
                                        struct sctp_tmit_chunk *chk;

                                        chk = TAILQ_FIRST(&stcb->asoc.sent_queue);
                                        sctp_timer_start(SCTP_TIMER_TYPE_SEND, stcb->sctp_ep, stcb, chk->whoTo);
                                }
                        }
                        break;
                case SCTP_COOKIE_ACK:
                        SCTPDBG(SCTP_DEBUG_INPUT3, "SCTP_COOKIE-ACK, stcb %p\n", (void *)stcb);
                        if ((stcb == NULL) || chk_length != sizeof(struct sctp_cookie_ack_chunk)) {
                                if (locked_tcb) {
                                        SCTP_TCB_UNLOCK(locked_tcb);
                                }
                                return (NULL);
                        }
                        if (inp->sctp_flags & SCTP_PCB_FLAGS_SOCKET_GONE) {
                                /* We are not interested anymore */
                                if ((stcb) && (stcb->asoc.total_output_queue_size)) {
                                        ;
                                } else if (stcb) {
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                                        so = SCTP_INP_SO(inp);
                                        atomic_add_int(&stcb->asoc.refcnt, 1);
                                        SCTP_TCB_UNLOCK(stcb);
                                        SCTP_SOCKET_LOCK(so, 1);
                                        SCTP_TCB_LOCK(stcb);
                                        atomic_subtract_int(&stcb->asoc.refcnt, 1);
#endif
                                        (void)sctp_free_assoc(inp, stcb, SCTP_NORMAL_PROC,
                                            SCTP_FROM_SCTP_INPUT + SCTP_LOC_30);
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                                        SCTP_SOCKET_UNLOCK(so, 1);
#endif
                                        *offset = length;
                                        return (NULL);
                                }
                        }
                        /* He's alive so give him credit */
                        if ((stcb) && netp && *netp) {
                                if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_THRESHOLD_LOGGING) {
                                        sctp_misc_ints(SCTP_THRESHOLD_CLEAR,
                                            stcb->asoc.overall_error_count,
                                            0,
                                            SCTP_FROM_SCTP_INPUT,
                                            __LINE__);
                                }
                                stcb->asoc.overall_error_count = 0;
                                sctp_handle_cookie_ack((struct sctp_cookie_ack_chunk *)ch, stcb, *netp);
                        }
                        break;
                case SCTP_ECN_ECHO:
                        SCTPDBG(SCTP_DEBUG_INPUT3, "SCTP_ECN-ECHO\n");
                        /* He's alive so give him credit */
                        if ((stcb == NULL) || (chk_length != sizeof(struct sctp_ecne_chunk))) {
                                /* Its not ours */
                                if (locked_tcb) {
                                        SCTP_TCB_UNLOCK(locked_tcb);
                                }
                                *offset = length;
                                return (NULL);
                        }
                        if (stcb) {
                                if (stcb->asoc.ecn_supported == 0) {
                                        goto unknown_chunk;
                                }
                                if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_THRESHOLD_LOGGING) {
                                        sctp_misc_ints(SCTP_THRESHOLD_CLEAR,
                                            stcb->asoc.overall_error_count,
                                            0,
                                            SCTP_FROM_SCTP_INPUT,
                                            __LINE__);
                                }
                                stcb->asoc.overall_error_count = 0;
                                sctp_handle_ecn_echo((struct sctp_ecne_chunk *)ch,
                                    stcb);
                                ecne_seen = 1;
                        }
                        break;
                case SCTP_ECN_CWR:
                        SCTPDBG(SCTP_DEBUG_INPUT3, "SCTP_ECN-CWR\n");
                        /* He's alive so give him credit */
                        if ((stcb == NULL) || (chk_length != sizeof(struct sctp_cwr_chunk))) {
                                /* Its not ours */
                                if (locked_tcb) {
                                        SCTP_TCB_UNLOCK(locked_tcb);
                                }
                                *offset = length;
                                return (NULL);
                        }
                        if (stcb) {
                                if (stcb->asoc.ecn_supported == 0) {
                                        goto unknown_chunk;
                                }
                                if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_THRESHOLD_LOGGING) {
                                        sctp_misc_ints(SCTP_THRESHOLD_CLEAR,
                                            stcb->asoc.overall_error_count,
                                            0,
                                            SCTP_FROM_SCTP_INPUT,
                                            __LINE__);
                                }
                                stcb->asoc.overall_error_count = 0;
                                sctp_handle_ecn_cwr((struct sctp_cwr_chunk *)ch, stcb, *netp);
                        }
                        break;
                case SCTP_SHUTDOWN_COMPLETE:
                        SCTPDBG(SCTP_DEBUG_INPUT3, "SCTP_SHUTDOWN-COMPLETE, stcb %p\n", (void *)stcb);
                        /* must be first and only chunk */
                        if ((num_chunks > 1) ||
                            (length - *offset > (int)SCTP_SIZE32(chk_length))) {
                                *offset = length;
                                if (locked_tcb) {
                                        SCTP_TCB_UNLOCK(locked_tcb);
                                }
                                return (NULL);
                        }
                        if ((stcb) && netp && *netp) {
                                sctp_handle_shutdown_complete((struct sctp_shutdown_complete_chunk *)ch,
                                    stcb, *netp);
                        }
                        *offset = length;
                        return (NULL);
                        break;
                case SCTP_ASCONF:
                        SCTPDBG(SCTP_DEBUG_INPUT3, "SCTP_ASCONF\n");
                        /* He's alive so give him credit */
                        if (stcb) {
                                if (stcb->asoc.asconf_supported == 0) {
                                        goto unknown_chunk;
                                }
                                if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_THRESHOLD_LOGGING) {
                                        sctp_misc_ints(SCTP_THRESHOLD_CLEAR,
                                            stcb->asoc.overall_error_count,
                                            0,
                                            SCTP_FROM_SCTP_INPUT,
                                            __LINE__);
                                }
                                stcb->asoc.overall_error_count = 0;
                                sctp_handle_asconf(m, *offset, src,
                                    (struct sctp_asconf_chunk *)ch, stcb, asconf_cnt == 0);
                                asconf_cnt++;
                        }
                        break;
                case SCTP_ASCONF_ACK:
                        SCTPDBG(SCTP_DEBUG_INPUT3, "SCTP_ASCONF-ACK\n");
                        if (chk_length < sizeof(struct sctp_asconf_ack_chunk)) {
                                /* Its not ours */
                                if (locked_tcb) {
                                        SCTP_TCB_UNLOCK(locked_tcb);
                                }
                                *offset = length;
                                return (NULL);
                        }
                        if ((stcb) && netp && *netp) {
                                if (stcb->asoc.asconf_supported == 0) {
                                        goto unknown_chunk;
                                }
                                /* He's alive so give him credit */
                                if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_THRESHOLD_LOGGING) {
                                        sctp_misc_ints(SCTP_THRESHOLD_CLEAR,
                                            stcb->asoc.overall_error_count,
                                            0,
                                            SCTP_FROM_SCTP_INPUT,
                                            __LINE__);
                                }
                                stcb->asoc.overall_error_count = 0;
                                sctp_handle_asconf_ack(m, *offset,
                                    (struct sctp_asconf_ack_chunk *)ch, stcb, *netp, &abort_no_unlock);
                                if (abort_no_unlock)
                                        return (NULL);
                        }
                        break;
                case SCTP_FORWARD_CUM_TSN:
                        SCTPDBG(SCTP_DEBUG_INPUT3, "SCTP_FWD-TSN\n");
                        if (chk_length < sizeof(struct sctp_forward_tsn_chunk)) {
                                /* Its not ours */
                                if (locked_tcb) {
                                        SCTP_TCB_UNLOCK(locked_tcb);
                                }
                                *offset = length;
                                return (NULL);
                        }
                        /* He's alive so give him credit */
                        if (stcb) {
                                int abort_flag = 0;

                                if (stcb->asoc.prsctp_supported == 0) {
                                        goto unknown_chunk;
                                }
                                stcb->asoc.overall_error_count = 0;
                                if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_THRESHOLD_LOGGING) {
                                        sctp_misc_ints(SCTP_THRESHOLD_CLEAR,
                                            stcb->asoc.overall_error_count,
                                            0,
                                            SCTP_FROM_SCTP_INPUT,
                                            __LINE__);
                                }
                                *fwd_tsn_seen = 1;
                                if (inp->sctp_flags & SCTP_PCB_FLAGS_SOCKET_GONE) {
                                        /* We are not interested anymore */
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                                        so = SCTP_INP_SO(inp);
                                        atomic_add_int(&stcb->asoc.refcnt, 1);
                                        SCTP_TCB_UNLOCK(stcb);
                                        SCTP_SOCKET_LOCK(so, 1);
                                        SCTP_TCB_LOCK(stcb);
                                        atomic_subtract_int(&stcb->asoc.refcnt, 1);
#endif
                                        (void)sctp_free_assoc(inp, stcb, SCTP_NORMAL_PROC,
                                            SCTP_FROM_SCTP_INPUT + SCTP_LOC_31);
#if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
                                        SCTP_SOCKET_UNLOCK(so, 1);
#endif
                                        *offset = length;
                                        return (NULL);
                                }
                                sctp_handle_forward_tsn(stcb,
                                    (struct sctp_forward_tsn_chunk *)ch, &abort_flag, m, *offset);
                                if (abort_flag) {
                                        *offset = length;
                                        return (NULL);
                                } else {
                                        if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_THRESHOLD_LOGGING) {
                                                sctp_misc_ints(SCTP_THRESHOLD_CLEAR,
                                                    stcb->asoc.overall_error_count,
                                                    0,
                                                    SCTP_FROM_SCTP_INPUT,
                                                    __LINE__);
                                        }
                                        stcb->asoc.overall_error_count = 0;
                                }

                        }
                        break;
                case SCTP_STREAM_RESET:
                        SCTPDBG(SCTP_DEBUG_INPUT3, "SCTP_STREAM_RESET\n");
                        if (((stcb == NULL) || (ch == NULL) || (chk_length < sizeof(struct sctp_stream_reset_tsn_req)))) {
                                /* Its not ours */
                                if (locked_tcb) {
                                        SCTP_TCB_UNLOCK(locked_tcb);
                                }
                                *offset = length;
                                return (NULL);
                        }
                        if (stcb->asoc.reconfig_supported == 0) {
                                goto unknown_chunk;
                        }
                        if (sctp_handle_stream_reset(stcb, m, *offset, ch)) {
                                /* stop processing */
                                *offset = length;
                                return (NULL);
                        }
                        break;
                case SCTP_PACKET_DROPPED:
                        SCTPDBG(SCTP_DEBUG_INPUT3, "SCTP_PACKET_DROPPED\n");
                        /* re-get it all please */
                        if (chk_length < sizeof(struct sctp_pktdrop_chunk)) {
                                /* Its not ours */
                                if (locked_tcb) {
                                        SCTP_TCB_UNLOCK(locked_tcb);
                                }
                                *offset = length;
                                return (NULL);
                        }
                        if (ch && (stcb) && netp && (*netp)) {
                                if (stcb->asoc.pktdrop_supported == 0) {
                                        goto unknown_chunk;
                                }
                                sctp_handle_packet_dropped((struct sctp_pktdrop_chunk *)ch,
                                    stcb, *netp,
                                    min(chk_length, (sizeof(chunk_buf) - 4)));

                        }
                        break;
                case SCTP_AUTHENTICATION:
                        SCTPDBG(SCTP_DEBUG_INPUT3, "SCTP_AUTHENTICATION\n");
                        if (stcb == NULL) {
                                /* save the first AUTH for later processing */
                                if (auth_skipped == 0) {
                                        auth_offset = *offset;
                                        auth_len = chk_length;
                                        auth_skipped = 1;
                                }
                                /* skip this chunk (temporarily) */
                                goto next_chunk;
                        }
                        if (stcb->asoc.auth_supported == 0) {
                                goto unknown_chunk;
                        }
                        if ((chk_length < (sizeof(struct sctp_auth_chunk))) ||
                            (chk_length > (sizeof(struct sctp_auth_chunk) +
                            SCTP_AUTH_DIGEST_LEN_MAX))) {
                                /* Its not ours */
                                if (locked_tcb) {
                                        SCTP_TCB_UNLOCK(locked_tcb);
                                }
                                *offset = length;
                                return (NULL);
                        }
                        if (got_auth == 1) {
                                /* skip this chunk... it's already auth'd */
                                goto next_chunk;
                        }
                        got_auth = 1;
                        if ((ch == NULL) || sctp_handle_auth(stcb, (struct sctp_auth_chunk *)ch,
                            m, *offset)) {
                                /* auth HMAC failed so dump the packet */
                                *offset = length;
                                return (stcb);
                        } else {
                                /* remaining chunks are HMAC checked */
                                stcb->asoc.authenticated = 1;
                        }
                        break;

                default:
        unknown_chunk:
                        /* it's an unknown chunk! */
                        if ((ch->chunk_type & 0x40) && (stcb != NULL)) {
                                struct sctp_gen_error_cause *cause;
                                int len;

                                op_err = sctp_get_mbuf_for_msg(sizeof(struct sctp_gen_error_cause),
                                    0, M_NOWAIT, 1, MT_DATA);
                                if (op_err != NULL) {
                                        len = min(SCTP_SIZE32(chk_length), (uint32_t) (length - *offset));
                                        cause = mtod(op_err, struct sctp_gen_error_cause *);
                                        cause->code = htons(SCTP_CAUSE_UNRECOG_CHUNK);
                                        cause->length = htons(len + sizeof(struct sctp_gen_error_cause));
                                        SCTP_BUF_LEN(op_err) = sizeof(struct sctp_gen_error_cause);
                                        SCTP_BUF_NEXT(op_err) = SCTP_M_COPYM(m, *offset, len, M_NOWAIT);
                                        if (SCTP_BUF_NEXT(op_err) != NULL) {
#ifdef SCTP_MBUF_LOGGING
                                                if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_MBUF_LOGGING_ENABLE) {
                                                        sctp_log_mbc(SCTP_BUF_NEXT(op_err), SCTP_MBUF_ICOPY);
                                                }
#endif
                                                sctp_queue_op_err(stcb, op_err);
                                        } else {
                                                sctp_m_freem(op_err);
                                        }
                                }
                        }
                        if ((ch->chunk_type & 0x80) == 0) {
                                /* discard this packet */
                                *offset = length;
                                return (stcb);
                        }       /* else skip this bad chunk and continue... */
                        break;
                }               /* switch (ch->chunk_type) */


next_chunk:
                /* get the next chunk */
                *offset += SCTP_SIZE32(chk_length);
                if (*offset >= length) {
                        /* no more data left in the mbuf chain */
                        break;
                }
                ch = (struct sctp_chunkhdr *)sctp_m_getptr(m, *offset,
                    sizeof(struct sctp_chunkhdr), chunk_buf);
                if (ch == NULL) {
                        if (locked_tcb) {
                                SCTP_TCB_UNLOCK(locked_tcb);
                        }
                        *offset = length;
                        return (NULL);
                }
        }                       /* while */

        if (asconf_cnt > 0 && stcb != NULL) {
                sctp_send_asconf_ack(stcb);
        }
        return (stcb);
}


/*
 * common input chunk processing (v4 and v6)
 */
void
sctp_common_input_processing(struct mbuf **mm, int iphlen, int offset, int length,
    struct sockaddr *src, struct sockaddr *dst,
    struct sctphdr *sh, struct sctp_chunkhdr *ch,
#if !defined(SCTP_WITH_NO_CSUM)
    uint8_t compute_crc,
#endif
    uint8_t ecn_bits,
    uint8_t mflowtype, uint32_t mflowid, uint16_t fibnum,
    uint32_t vrf_id, uint16_t port)
{
        uint32_t high_tsn;
        int fwd_tsn_seen = 0, data_processed = 0;
        struct mbuf *m = *mm, *op_err;
        char msg[SCTP_DIAG_INFO_LEN];
        int un_sent;
        int cnt_ctrl_ready = 0;
        struct sctp_inpcb *inp = NULL, *inp_decr = NULL;
        struct sctp_tcb *stcb = NULL;
        struct sctp_nets *net = NULL;

        SCTP_STAT_INCR(sctps_recvdatagrams);
#ifdef SCTP_AUDITING_ENABLED
        sctp_audit_log(0xE0, 1);
        sctp_auditing(0, inp, stcb, net);
#endif
#if !defined(SCTP_WITH_NO_CSUM)
        if (compute_crc != 0) {
                uint32_t check, calc_check;

                check = sh->checksum;
                sh->checksum = 0;
                calc_check = sctp_calculate_cksum(m, iphlen);
                sh->checksum = check;
                if (calc_check != check) {
                        SCTPDBG(SCTP_DEBUG_INPUT1, "Bad CSUM on SCTP packet calc_check:%x check:%x  m:%p mlen:%d iphlen:%d\n",
                            calc_check, check, (void *)m, length, iphlen);
                        stcb = sctp_findassociation_addr(m, offset, src, dst,
                            sh, ch, &inp, &net, vrf_id);
#if defined(INET) || defined(INET6)
                        if ((ch->chunk_type != SCTP_INITIATION) &&
                            (net != NULL) && (net->port != port)) {
                                if (net->port == 0) {
                                        /* UDP encapsulation turned on. */
                                        net->mtu -= sizeof(struct udphdr);
                                        if (stcb->asoc.smallest_mtu > net->mtu) {
                                                sctp_pathmtu_adjustment(stcb, net->mtu);
                                        }
                                } else if (port == 0) {
                                        /* UDP encapsulation turned off. */
                                        net->mtu += sizeof(struct udphdr);
                                        /* XXX Update smallest_mtu */
                                }
                                net->port = port;
                        }
#endif
                        if (net != NULL) {
                                net->flowtype = mflowtype;
                                net->flowid = mflowid;
                        }
                        if ((inp != NULL) && (stcb != NULL)) {
                                sctp_send_packet_dropped(stcb, net, m, length, iphlen, 1);
                                sctp_chunk_output(inp, stcb, SCTP_OUTPUT_FROM_INPUT_ERROR, SCTP_SO_NOT_LOCKED);
                        } else if ((inp != NULL) && (stcb == NULL)) {
                                inp_decr = inp;
                        }
                        SCTP_STAT_INCR(sctps_badsum);
                        SCTP_STAT_INCR_COUNTER32(sctps_checksumerrors);
                        goto out;
                }
        }
#endif
        /* Destination port of 0 is illegal, based on RFC4960. */
        if (sh->dest_port == 0) {
                SCTP_STAT_INCR(sctps_hdrops);
                goto out;
        }
        stcb = sctp_findassociation_addr(m, offset, src, dst,
            sh, ch, &inp, &net, vrf_id);
#if defined(INET) || defined(INET6)
        if ((ch->chunk_type != SCTP_INITIATION) &&
            (net != NULL) && (net->port != port)) {
                if (net->port == 0) {
                        /* UDP encapsulation turned on. */
                        net->mtu -= sizeof(struct udphdr);
                        if (stcb->asoc.smallest_mtu > net->mtu) {
                                sctp_pathmtu_adjustment(stcb, net->mtu);
                        }
                } else if (port == 0) {
                        /* UDP encapsulation turned off. */
                        net->mtu += sizeof(struct udphdr);
                        /* XXX Update smallest_mtu */
                }
                net->port = port;
        }
#endif
        if (net != NULL) {
                net->flowtype = mflowtype;
                net->flowid = mflowid;
        }
        if (inp == NULL) {
                SCTP_STAT_INCR(sctps_noport);
                if (badport_bandlim(BANDLIM_SCTP_OOTB) < 0) {
                        goto out;
                }
                if (ch->chunk_type == SCTP_SHUTDOWN_ACK) {
                        sctp_send_shutdown_complete2(src, dst, sh,
                            mflowtype, mflowid, fibnum,
                            vrf_id, port);
                        goto out;
                }
                if (ch->chunk_type == SCTP_SHUTDOWN_COMPLETE) {
                        goto out;
                }
                if (ch->chunk_type != SCTP_ABORT_ASSOCIATION) {
                        if ((SCTP_BASE_SYSCTL(sctp_blackhole) == 0) ||
                            ((SCTP_BASE_SYSCTL(sctp_blackhole) == 1) &&
                            (ch->chunk_type != SCTP_INIT))) {
                                op_err = sctp_generate_cause(SCTP_BASE_SYSCTL(sctp_diag_info_code),
                                    "Out of the blue");
                                sctp_send_abort(m, iphlen, src, dst,
                                    sh, 0, op_err,
                                    mflowtype, mflowid, fibnum,
                                    vrf_id, port);
                        }
                }
                goto out;
        } else if (stcb == NULL) {
                inp_decr = inp;
        }
#ifdef IPSEC
        /*-
         * I very much doubt any of the IPSEC stuff will work but I have no
         * idea, so I will leave it in place.
         */
        if (inp != NULL) {
                switch (dst->sa_family) {
#ifdef INET
                case AF_INET:
                        if (ipsec4_in_reject(m, &inp->ip_inp.inp)) {
                                SCTP_STAT_INCR(sctps_hdrops);
                                goto out;
                        }
                        break;
#endif
#ifdef INET6
                case AF_INET6:
                        if (ipsec6_in_reject(m, &inp->ip_inp.inp)) {
                                SCTP_STAT_INCR(sctps_hdrops);
                                goto out;
                        }
                        break;
#endif
                default:
                        break;
                }
        }
#endif
        SCTPDBG(SCTP_DEBUG_INPUT1, "Ok, Common input processing called, m:%p iphlen:%d offset:%d length:%d stcb:%p\n",
            (void *)m, iphlen, offset, length, (void *)stcb);
        if (stcb) {
                /* always clear this before beginning a packet */
                stcb->asoc.authenticated = 0;
                stcb->asoc.seen_a_sack_this_pkt = 0;
                SCTPDBG(SCTP_DEBUG_INPUT1, "stcb:%p state:%x\n",
                    (void *)stcb, stcb->asoc.state);

                if ((stcb->asoc.state & SCTP_STATE_WAS_ABORTED) ||
                    (stcb->asoc.state & SCTP_STATE_ABOUT_TO_BE_FREED)) {
                        /*-
                         * If we hit here, we had a ref count
                         * up when the assoc was aborted and the
                         * timer is clearing out the assoc, we should
                         * NOT respond to any packet.. its OOTB.
                         */
                        SCTP_TCB_UNLOCK(stcb);
                        stcb = NULL;
                        snprintf(msg, sizeof(msg), "OOTB, %s:%d at %s", __FILE__, __LINE__, __func__);
                        op_err = sctp_generate_cause(SCTP_BASE_SYSCTL(sctp_diag_info_code),
                            msg);
                        sctp_handle_ootb(m, iphlen, offset, src, dst, sh, inp, op_err,
                            mflowtype, mflowid, inp->fibnum,
                            vrf_id, port);
                        goto out;
                }
        }
        if (IS_SCTP_CONTROL(ch)) {
                /* process the control portion of the SCTP packet */
                /* sa_ignore NO_NULL_CHK */
                stcb = sctp_process_control(m, iphlen, &offset, length,
                    src, dst, sh, ch,
                    inp, stcb, &net, &fwd_tsn_seen,
                    mflowtype, mflowid, fibnum,
                    vrf_id, port);
                if (stcb) {
                        /*
                         * This covers us if the cookie-echo was there and
                         * it changes our INP.
                         */
                        inp = stcb->sctp_ep;
#if defined(INET) || defined(INET6)
                        if ((ch->chunk_type != SCTP_INITIATION) &&
                            (net != NULL) && (net->port != port)) {
                                if (net->port == 0) {
                                        /* UDP encapsulation turned on. */
                                        net->mtu -= sizeof(struct udphdr);
                                        if (stcb->asoc.smallest_mtu > net->mtu) {
                                                sctp_pathmtu_adjustment(stcb, net->mtu);
                                        }
                                } else if (port == 0) {
                                        /* UDP encapsulation turned off. */
                                        net->mtu += sizeof(struct udphdr);
                                        /* XXX Update smallest_mtu */
                                }
                                net->port = port;
                        }
#endif
                }
        } else {
                /*
                 * no control chunks, so pre-process DATA chunks (these
                 * checks are taken care of by control processing)
                 */

                /*
                 * if DATA only packet, and auth is required, then punt...
                 * can't have authenticated without any AUTH (control)
                 * chunks
                 */
                if ((stcb != NULL) &&
                    (stcb->asoc.auth_supported == 1) &&
                    sctp_auth_is_required_chunk(SCTP_DATA, stcb->asoc.local_auth_chunks)) {
                        /* "silently" ignore */
                        SCTP_STAT_INCR(sctps_recvauthmissing);
                        goto out;
                }
                if (stcb == NULL) {
                        /* out of the blue DATA chunk */
                        snprintf(msg, sizeof(msg), "OOTB, %s:%d at %s", __FILE__, __LINE__, __func__);
                        op_err = sctp_generate_cause(SCTP_BASE_SYSCTL(sctp_diag_info_code),
                            msg);
                        sctp_handle_ootb(m, iphlen, offset, src, dst, sh, inp, op_err,
                            mflowtype, mflowid, fibnum,
                            vrf_id, port);
                        goto out;
                }
                if (stcb->asoc.my_vtag != ntohl(sh->v_tag)) {
                        /* v_tag mismatch! */
                        SCTP_STAT_INCR(sctps_badvtag);
                        goto out;
                }
        }

        if (stcb == NULL) {
                /*
                 * no valid TCB for this packet, or we found it's a bad
                 * packet while processing control, or we're done with this
                 * packet (done or skip rest of data), so we drop it...
                 */
                goto out;
        }
        /*
         * DATA chunk processing
         */
        /* plow through the data chunks while length > offset */

        /*
         * Rest should be DATA only.  Check authentication state if AUTH for
         * DATA is required.
         */
        if ((length > offset) &&
            (stcb != NULL) &&
            (stcb->asoc.auth_supported == 1) &&
            sctp_auth_is_required_chunk(SCTP_DATA, stcb->asoc.local_auth_chunks) &&
            !stcb->asoc.authenticated) {
                /* "silently" ignore */
                SCTP_STAT_INCR(sctps_recvauthmissing);
                SCTPDBG(SCTP_DEBUG_AUTH1,
                    "Data chunk requires AUTH, skipped\n");
                goto trigger_send;
        }
        if (length > offset) {
                int retval;

                /*
                 * First check to make sure our state is correct. We would
                 * not get here unless we really did have a tag, so we don't
                 * abort if this happens, just dump the chunk silently.
                 */
                switch (SCTP_GET_STATE(&stcb->asoc)) {
                case SCTP_STATE_COOKIE_ECHOED:
                        /*
                         * we consider data with valid tags in this state
                         * shows us the cookie-ack was lost. Imply it was
                         * there.
                         */
                        if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_THRESHOLD_LOGGING) {
                                sctp_misc_ints(SCTP_THRESHOLD_CLEAR,
                                    stcb->asoc.overall_error_count,
                                    0,
                                    SCTP_FROM_SCTP_INPUT,
                                    __LINE__);
                        }
                        stcb->asoc.overall_error_count = 0;
                        sctp_handle_cookie_ack((struct sctp_cookie_ack_chunk *)ch, stcb, net);
                        break;
                case SCTP_STATE_COOKIE_WAIT:
                        /*
                         * We consider OOTB any data sent during asoc setup.
                         */
                        snprintf(msg, sizeof(msg), "OOTB, %s:%d at %s", __FILE__, __LINE__, __func__);
                        op_err = sctp_generate_cause(SCTP_BASE_SYSCTL(sctp_diag_info_code),
                            msg);
                        sctp_handle_ootb(m, iphlen, offset, src, dst, sh, inp, op_err,
                            mflowtype, mflowid, inp->fibnum,
                            vrf_id, port);
                        goto out;
                        /* sa_ignore NOTREACHED */
                        break;
                case SCTP_STATE_EMPTY:  /* should not happen */
                case SCTP_STATE_INUSE:  /* should not happen */
                case SCTP_STATE_SHUTDOWN_RECEIVED:      /* This is a peer error */
                case SCTP_STATE_SHUTDOWN_ACK_SENT:
                default:
                        goto out;
                        /* sa_ignore NOTREACHED */
                        break;
                case SCTP_STATE_OPEN:
                case SCTP_STATE_SHUTDOWN_SENT:
                        break;
                }
                /* plow through the data chunks while length > offset */
                retval = sctp_process_data(mm, iphlen, &offset, length,
                    inp, stcb, net, &high_tsn);
                if (retval == 2) {
                        /*
                         * The association aborted, NO UNLOCK needed since
                         * the association is destroyed.
                         */
                        stcb = NULL;
                        goto out;
                }
                data_processed = 1;
                /*
                 * Anything important needs to have been m_copy'ed in
                 * process_data
                 */
        }
        /* take care of ecn */
        if ((data_processed == 1) &&
            (stcb->asoc.ecn_supported == 1) &&
            ((ecn_bits & SCTP_CE_BITS) == SCTP_CE_BITS)) {
                /* Yep, we need to add a ECNE */
                sctp_send_ecn_echo(stcb, net, high_tsn);
        }
        if ((data_processed == 0) && (fwd_tsn_seen)) {
                int was_a_gap;
                uint32_t highest_tsn;

                if (SCTP_TSN_GT(stcb->asoc.highest_tsn_inside_nr_map, stcb->asoc.highest_tsn_inside_map)) {
                        highest_tsn = stcb->asoc.highest_tsn_inside_nr_map;
                } else {
                        highest_tsn = stcb->asoc.highest_tsn_inside_map;
                }
                was_a_gap = SCTP_TSN_GT(highest_tsn, stcb->asoc.cumulative_tsn);
                stcb->asoc.send_sack = 1;
                sctp_sack_check(stcb, was_a_gap);
        } else if (fwd_tsn_seen) {
                stcb->asoc.send_sack = 1;
        }
        /* trigger send of any chunks in queue... */
trigger_send:
#ifdef SCTP_AUDITING_ENABLED
        sctp_audit_log(0xE0, 2);
        sctp_auditing(1, inp, stcb, net);
#endif
        SCTPDBG(SCTP_DEBUG_INPUT1,
            "Check for chunk output prw:%d tqe:%d tf=%d\n",
            stcb->asoc.peers_rwnd,
            TAILQ_EMPTY(&stcb->asoc.control_send_queue),
            stcb->asoc.total_flight);
        un_sent = (stcb->asoc.total_output_queue_size - stcb->asoc.total_flight);
        if (!TAILQ_EMPTY(&stcb->asoc.control_send_queue)) {
                cnt_ctrl_ready = stcb->asoc.ctrl_queue_cnt - stcb->asoc.ecn_echo_cnt_onq;
        }
        if (cnt_ctrl_ready || stcb->asoc.trigger_reset ||
            ((un_sent) &&
            (stcb->asoc.peers_rwnd > 0 ||
            (stcb->asoc.peers_rwnd <= 0 && stcb->asoc.total_flight == 0)))) {
                SCTPDBG(SCTP_DEBUG_INPUT3, "Calling chunk OUTPUT\n");
                sctp_chunk_output(inp, stcb, SCTP_OUTPUT_FROM_CONTROL_PROC, SCTP_SO_NOT_LOCKED);
                SCTPDBG(SCTP_DEBUG_INPUT3, "chunk OUTPUT returns\n");
        }
#ifdef SCTP_AUDITING_ENABLED
        sctp_audit_log(0xE0, 3);
        sctp_auditing(2, inp, stcb, net);
#endif
out:
        if (stcb != NULL) {
                SCTP_TCB_UNLOCK(stcb);
        }
        if (inp_decr != NULL) {
                /* reduce ref-count */
                SCTP_INP_WLOCK(inp_decr);
                SCTP_INP_DECR_REF(inp_decr);
                SCTP_INP_WUNLOCK(inp_decr);
        }
        return;
}

#ifdef INET
void
sctp_input_with_port(struct mbuf *i_pak, int off, uint16_t port)
{
        struct mbuf *m;
        int iphlen;
        uint32_t vrf_id = 0;
        uint8_t ecn_bits;
        struct sockaddr_in src, dst;
        struct ip *ip;
        struct sctphdr *sh;
        struct sctp_chunkhdr *ch;
        int length, offset;

#if !defined(SCTP_WITH_NO_CSUM)
        uint8_t compute_crc;

#endif
        uint32_t mflowid;
        uint8_t mflowtype;
        uint16_t fibnum;

        iphlen = off;
        if (SCTP_GET_PKT_VRFID(i_pak, vrf_id)) {
                SCTP_RELEASE_PKT(i_pak);
                return;
        }
        m = SCTP_HEADER_TO_CHAIN(i_pak);
#ifdef SCTP_MBUF_LOGGING
        /* Log in any input mbufs */
        if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_MBUF_LOGGING_ENABLE) {
                sctp_log_mbc(m, SCTP_MBUF_INPUT);
        }
#endif
#ifdef SCTP_PACKET_LOGGING
        if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_LAST_PACKET_TRACING) {
                sctp_packet_log(m);
        }
#endif
        SCTPDBG(SCTP_DEBUG_CRCOFFLOAD,
            "sctp_input(): Packet of length %d received on %s with csum_flags 0x%b.\n",
            m->m_pkthdr.len,
            if_name(m->m_pkthdr.rcvif),
            (int)m->m_pkthdr.csum_flags, CSUM_BITS);
        mflowid = m->m_pkthdr.flowid;
        mflowtype = M_HASHTYPE_GET(m);
        fibnum = M_GETFIB(m);
        SCTP_STAT_INCR(sctps_recvpackets);
        SCTP_STAT_INCR_COUNTER64(sctps_inpackets);
        /* Get IP, SCTP, and first chunk header together in the first mbuf. */
        offset = iphlen + sizeof(struct sctphdr) + sizeof(struct sctp_chunkhdr);
        if (SCTP_BUF_LEN(m) < offset) {
                if ((m = m_pullup(m, offset)) == NULL) {
                        SCTP_STAT_INCR(sctps_hdrops);
                        return;
                }
        }
        ip = mtod(m, struct ip *);
        sh = (struct sctphdr *)((caddr_t)ip + iphlen);
        ch = (struct sctp_chunkhdr *)((caddr_t)sh + sizeof(struct sctphdr));
        offset -= sizeof(struct sctp_chunkhdr);
        memset(&src, 0, sizeof(struct sockaddr_in));
        src.sin_family = AF_INET;
        src.sin_len = sizeof(struct sockaddr_in);
        src.sin_port = sh->src_port;
        src.sin_addr = ip->ip_src;
        memset(&dst, 0, sizeof(struct sockaddr_in));
        dst.sin_family = AF_INET;
        dst.sin_len = sizeof(struct sockaddr_in);
        dst.sin_port = sh->dest_port;
        dst.sin_addr = ip->ip_dst;
        length = ntohs(ip->ip_len);
        /* Validate mbuf chain length with IP payload length. */
        if (SCTP_HEADER_LEN(m) != length) {
                SCTPDBG(SCTP_DEBUG_INPUT1,
                    "sctp_input() length:%d reported length:%d\n", length, SCTP_HEADER_LEN(m));
                SCTP_STAT_INCR(sctps_hdrops);
                goto out;
        }
        /* SCTP does not allow broadcasts or multicasts */
        if (IN_MULTICAST(ntohl(dst.sin_addr.s_addr))) {
                goto out;
        }
        if (SCTP_IS_IT_BROADCAST(dst.sin_addr, m)) {
                goto out;
        }
        ecn_bits = ip->ip_tos;
#if defined(SCTP_WITH_NO_CSUM)
        SCTP_STAT_INCR(sctps_recvnocrc);
#else
        if (m->m_pkthdr.csum_flags & CSUM_SCTP_VALID) {
                SCTP_STAT_INCR(sctps_recvhwcrc);
                compute_crc = 0;
        } else {
                SCTP_STAT_INCR(sctps_recvswcrc);
                compute_crc = 1;
        }
#endif
        sctp_common_input_processing(&m, iphlen, offset, length,
            (struct sockaddr *)&src,
            (struct sockaddr *)&dst,
            sh, ch,
#if !defined(SCTP_WITH_NO_CSUM)
            compute_crc,
#endif
            ecn_bits,
            mflowtype, mflowid, fibnum,
            vrf_id, port);
out:
        if (m) {
                sctp_m_freem(m);
        }
        return;
}

#if defined(__FreeBSD__) && defined(SCTP_MCORE_INPUT) && defined(SMP)
extern int *sctp_cpuarry;

#endif

int
sctp_input(struct mbuf **mp, int *offp, int proto SCTP_UNUSED)
{
        struct mbuf *m;
        int off;

        m = *mp;
        off = *offp;
#if defined(__FreeBSD__) && defined(SCTP_MCORE_INPUT) && defined(SMP)
        if (mp_ncpus > 1) {
                struct ip *ip;
                struct sctphdr *sh;
                int offset;
                int cpu_to_use;
                uint32_t flowid, tag;

                if (M_HASHTYPE_GET(m) != M_HASHTYPE_NONE) {
                        flowid = m->m_pkthdr.flowid;
                } else {
                        /*
                         * No flow id built by lower layers fix it so we
                         * create one.
                         */
                        offset = off + sizeof(struct sctphdr);
                        if (SCTP_BUF_LEN(m) < offset) {
                                if ((m = m_pullup(m, offset)) == NULL) {
                                        SCTP_STAT_INCR(sctps_hdrops);
                                        return (IPPROTO_DONE);
                                }
                        }
                        ip = mtod(m, struct ip *);
                        sh = (struct sctphdr *)((caddr_t)ip + off);
                        tag = htonl(sh->v_tag);
                        flowid = tag ^ ntohs(sh->dest_port) ^ ntohs(sh->src_port);
                        m->m_pkthdr.flowid = flowid;
                        M_HASHTYPE_SET(m, M_HASHTYPE_OPAQUE);
                }
                cpu_to_use = sctp_cpuarry[flowid % mp_ncpus];
                sctp_queue_to_mcore(m, off, cpu_to_use);
                return (IPPROTO_DONE);
        }
#endif
        sctp_input_with_port(m, off, 0);
        return (IPPROTO_DONE);
}

#endif