This commit was generated by cvs2svn to compensate for changes in r159399,

[FreeBSD/FreeBSD.git] / sys / kern / uipc_socket.c

/*-
 * Copyright (c) 1982, 1986, 1988, 1990, 1993
 *      The Regents of the University of California.  All rights reserved.
 * Copyright (c) 2004 The FreeBSD Foundation
 * Copyright (c) 2004-2006 Robert N. M. Watson
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 * 4. Neither the name of the University 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 REGENTS 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 REGENTS 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.
 *
 *      @(#)uipc_socket.c       8.3 (Berkeley) 4/15/94
 */

/*
 * Comments on the socket life cycle:
 *
 * soalloc() sets of socket layer state for a socket, called only by
 * socreate() and sonewconn().  Socket layer private.
 *
 * sdealloc() tears down socket layer state for a socket, called only by
 * sofree() and sonewconn().  Socket layer private.
 *
 * pru_attach() associates protocol layer state with an allocated socket;
 * called only once, may fail, aborting socket allocation.  This is called
 * from socreate() and sonewconn().  Socket layer private.
 *
 * pru_detach() disassociates protocol layer state from an attached socket,
 * and will be called exactly once for sockets in which pru_attach() has
 * been successfully called.  If pru_attach() returned an error,
 * pru_detach() will not be called.  Socket layer private.
 *
 * socreate() creates a socket and attaches protocol state.  This is a public
 * interface that may be used by socket layer consumers to create new
 * sockets.
 *
 * sonewconn() creates a socket and attaches protocol state.  This is a
 * public interface  that may be used by protocols to create new sockets when
 * a new connection is received and will be available for accept() on a
 * listen socket.
 *
 * soclose() destroys a socket after possibly waiting for it to disconnect.
 * This is a public interface that socket consumers should use to close and
 * release a socket when done with it.
 *
 * soabort() destroys a socket without waiting for it to disconnect (used
 * only for incoming connections that are already partially or fully
 * connected).  This is used internally by the socket layer when clearing
 * listen socket queues (due to overflow or close on the listen socket), but
 * is also a public interface protocols may use to abort connections in
 * their incomplete listen queues should they no longer be required.  Sockets
 * placed in completed connection listen queues should not be aborted.
 *
 * sofree() will free a socket and its protocol state if all references on
 * the socket have been released, and is the public interface to attempt to
 * free a socket when a reference is removed.  This is a socket layer private
 * interface.
 *
 * NOTE: In addition to socreate() and soclose(), which provide a single
 * socket reference to the consumer to be managed as required, there are two
 * calls to explicitly manage socket references, soref(), and sorele().
 * Currently, these are generally required only when transitioning a socket
 * from a listen queue to a file descriptor, in order to prevent garbage
 * collection of the socket at an untimely moment.  For a number of reasons,
 * these interfaces are not preferred, and should be avoided.
 *
 * XXXRW: The behavior of sockets after soclose() but before the last
 * sorele() is poorly defined.  We can probably entirely eliminate them with
 * a little work, since consumers are managing references anyway.
 */

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

#include "opt_inet.h"
#include "opt_mac.h"
#include "opt_zero.h"
#include "opt_compat.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/fcntl.h>
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/mac.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/mutex.h>
#include <sys/domain.h>
#include <sys/file.h>                   /* for struct knote */
#include <sys/kernel.h>
#include <sys/event.h>
#include <sys/poll.h>
#include <sys/proc.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/resourcevar.h>
#include <sys/signalvar.h>
#include <sys/sysctl.h>
#include <sys/uio.h>
#include <sys/jail.h>

#include <vm/uma.h>

#ifdef COMPAT_IA32
#include <sys/mount.h>
#include <compat/freebsd32/freebsd32.h>

extern struct sysentvec ia32_freebsd_sysvec;
#endif

static int      soreceive_rcvoob(struct socket *so, struct uio *uio,
                    int flags);

static void     filt_sordetach(struct knote *kn);
static int      filt_soread(struct knote *kn, long hint);
static void     filt_sowdetach(struct knote *kn);
static int      filt_sowrite(struct knote *kn, long hint);
static int      filt_solisten(struct knote *kn, long hint);

static struct filterops solisten_filtops =
        { 1, NULL, filt_sordetach, filt_solisten };
static struct filterops soread_filtops =
        { 1, NULL, filt_sordetach, filt_soread };
static struct filterops sowrite_filtops =
        { 1, NULL, filt_sowdetach, filt_sowrite };

uma_zone_t socket_zone;
so_gen_t        so_gencnt;      /* generation count for sockets */

MALLOC_DEFINE(M_SONAME, "soname", "socket name");
MALLOC_DEFINE(M_PCB, "pcb", "protocol control block");

SYSCTL_DECL(_kern_ipc);

static int somaxconn = SOMAXCONN;
static int somaxconn_sysctl(SYSCTL_HANDLER_ARGS);
/* XXX: we dont have SYSCTL_USHORT */
SYSCTL_PROC(_kern_ipc, KIPC_SOMAXCONN, somaxconn, CTLTYPE_UINT | CTLFLAG_RW,
    0, sizeof(int), somaxconn_sysctl, "I", "Maximum pending socket connection "
    "queue size");
static int numopensockets;
SYSCTL_INT(_kern_ipc, OID_AUTO, numopensockets, CTLFLAG_RD,
    &numopensockets, 0, "Number of open sockets");
#ifdef ZERO_COPY_SOCKETS
/* These aren't static because they're used in other files. */
int so_zero_copy_send = 1;
int so_zero_copy_receive = 1;
SYSCTL_NODE(_kern_ipc, OID_AUTO, zero_copy, CTLFLAG_RD, 0,
    "Zero copy controls");
SYSCTL_INT(_kern_ipc_zero_copy, OID_AUTO, receive, CTLFLAG_RW,
    &so_zero_copy_receive, 0, "Enable zero copy receive");
SYSCTL_INT(_kern_ipc_zero_copy, OID_AUTO, send, CTLFLAG_RW,
    &so_zero_copy_send, 0, "Enable zero copy send");
#endif /* ZERO_COPY_SOCKETS */

/*
 * accept_mtx locks down per-socket fields relating to accept queues.  See
 * socketvar.h for an annotation of the protected fields of struct socket.
 */
struct mtx accept_mtx;
MTX_SYSINIT(accept_mtx, &accept_mtx, "accept", MTX_DEF);

/*
 * so_global_mtx protects so_gencnt, numopensockets, and the per-socket
 * so_gencnt field.
 */
static struct mtx so_global_mtx;
MTX_SYSINIT(so_global_mtx, &so_global_mtx, "so_glabel", MTX_DEF);

/*
 * Socket operation routines.
 * These routines are called by the routines in
 * sys_socket.c or from a system process, and
 * implement the semantics of socket operations by
 * switching out to the protocol specific routines.
 */

/*
 * Get a socket structure from our zone, and initialize it.
 * Note that it would probably be better to allocate socket
 * and PCB at the same time, but I'm not convinced that all
 * the protocols can be easily modified to do this.
 *
 * soalloc() returns a socket with a ref count of 0.
 */
struct socket *
soalloc(int mflags)
{
        struct socket *so;

        so = uma_zalloc(socket_zone, mflags | M_ZERO);
        if (so != NULL) {
#ifdef MAC
                if (mac_init_socket(so, mflags) != 0) {
                        uma_zfree(socket_zone, so);
                        return (NULL);
                }
#endif
                SOCKBUF_LOCK_INIT(&so->so_snd, "so_snd");
                SOCKBUF_LOCK_INIT(&so->so_rcv, "so_rcv");
                TAILQ_INIT(&so->so_aiojobq);
                mtx_lock(&so_global_mtx);
                so->so_gencnt = ++so_gencnt;
                ++numopensockets;
                mtx_unlock(&so_global_mtx);
        }
        return (so);
}

/*
 * socreate returns a socket with a ref count of 1.  The socket should be
 * closed with soclose().
 */
int
socreate(dom, aso, type, proto, cred, td)
        int dom;
        struct socket **aso;
        int type;
        int proto;
        struct ucred *cred;
        struct thread *td;
{
        struct protosw *prp;
        struct socket *so;
        int error;

        if (proto)
                prp = pffindproto(dom, proto, type);
        else
                prp = pffindtype(dom, type);

        if (prp == NULL || prp->pr_usrreqs->pru_attach == NULL ||
            prp->pr_usrreqs->pru_attach == pru_attach_notsupp)
                return (EPROTONOSUPPORT);

        if (jailed(cred) && jail_socket_unixiproute_only &&
            prp->pr_domain->dom_family != PF_LOCAL &&
            prp->pr_domain->dom_family != PF_INET &&
            prp->pr_domain->dom_family != PF_ROUTE) {
                return (EPROTONOSUPPORT);
        }

        if (prp->pr_type != type)
                return (EPROTOTYPE);
        so = soalloc(M_WAITOK);
        if (so == NULL)
                return (ENOBUFS);

        TAILQ_INIT(&so->so_incomp);
        TAILQ_INIT(&so->so_comp);
        so->so_type = type;
        so->so_cred = crhold(cred);
        so->so_proto = prp;
#ifdef MAC
        mac_create_socket(cred, so);
#endif
        knlist_init(&so->so_rcv.sb_sel.si_note, SOCKBUF_MTX(&so->so_rcv),
            NULL, NULL, NULL);
        knlist_init(&so->so_snd.sb_sel.si_note, SOCKBUF_MTX(&so->so_snd),
            NULL, NULL, NULL);
        so->so_count = 1;
        error = (*prp->pr_usrreqs->pru_attach)(so, proto, td);
        if (error) {
                ACCEPT_LOCK();
                SOCK_LOCK(so);
                so->so_state |= SS_NOFDREF;
                sorele(so);
                return (error);
        }
        *aso = so;
        return (0);
}

int
sobind(so, nam, td)
        struct socket *so;
        struct sockaddr *nam;
        struct thread *td;
{

        return ((*so->so_proto->pr_usrreqs->pru_bind)(so, nam, td));
}

void
sodealloc(struct socket *so)
{

        KASSERT(so->so_count == 0, ("sodealloc(): so_count %d", so->so_count));
        KASSERT(so->so_pcb == NULL, ("sodealloc(): so_pcb != NULL"));

        mtx_lock(&so_global_mtx);
        so->so_gencnt = ++so_gencnt;
        mtx_unlock(&so_global_mtx);
        if (so->so_rcv.sb_hiwat)
                (void)chgsbsize(so->so_cred->cr_uidinfo,
                    &so->so_rcv.sb_hiwat, 0, RLIM_INFINITY);
        if (so->so_snd.sb_hiwat)
                (void)chgsbsize(so->so_cred->cr_uidinfo,
                    &so->so_snd.sb_hiwat, 0, RLIM_INFINITY);
#ifdef INET
        /* remove acccept filter if one is present. */
        if (so->so_accf != NULL)
                do_setopt_accept_filter(so, NULL);
#endif
#ifdef MAC
        mac_destroy_socket(so);
#endif
        crfree(so->so_cred);
        SOCKBUF_LOCK_DESTROY(&so->so_snd);
        SOCKBUF_LOCK_DESTROY(&so->so_rcv);
        uma_zfree(socket_zone, so);
        mtx_lock(&so_global_mtx);
        --numopensockets;
        mtx_unlock(&so_global_mtx);
}

/*
 * solisten() transitions a socket from a non-listening state to a listening
 * state, but can also be used to update the listen queue depth on an
 * existing listen socket.  The protocol will call back into the sockets
 * layer using solisten_proto_check() and solisten_proto() to check and set
 * socket-layer listen state.  Call backs are used so that the protocol can
 * acquire both protocol and socket layer locks in whatever order is required
 * by the protocol.
 *
 * Protocol implementors are advised to hold the socket lock across the
 * socket-layer test and set to avoid races at the socket layer.
 */
int
solisten(so, backlog, td)
        struct socket *so;
        int backlog;
        struct thread *td;
{

        return ((*so->so_proto->pr_usrreqs->pru_listen)(so, backlog, td));
}

int
solisten_proto_check(so)
        struct socket *so;
{

        SOCK_LOCK_ASSERT(so);

        if (so->so_state & (SS_ISCONNECTED | SS_ISCONNECTING |
            SS_ISDISCONNECTING))
                return (EINVAL);
        return (0);
}

void
solisten_proto(so, backlog)
        struct socket *so;
        int backlog;
{

        SOCK_LOCK_ASSERT(so);

        if (backlog < 0 || backlog > somaxconn)
                backlog = somaxconn;
        so->so_qlimit = backlog;
        so->so_options |= SO_ACCEPTCONN;
}

/*
 * Attempt to free a socket.  This should really be sotryfree().
 *
 * sofree() will succeed if:
 *
 * - There are no outstanding file descriptor references or related consumers
 *   (so_count == 0).
 *
 * - The socket has been closed by user space, if ever open (SS_NOFDREF).
 *
 * - The protocol does not have an outstanding strong reference on the socket
 *   (SS_PROTOREF).
 *
 * - The socket is not in a completed connection queue, so a process has been
 *   notified that it is present.  If it is removed, the user process may
 *   block in accept() despite select() saying the socket was ready.
 *
 * Otherwise, it will quietly abort so that a future call to sofree(), when
 * conditions are right, can succeed.
 */
void
sofree(so)
        struct socket *so;
{
        struct socket *head;

        ACCEPT_LOCK_ASSERT();
        SOCK_LOCK_ASSERT(so);

        if ((so->so_state & SS_NOFDREF) == 0 || so->so_count != 0 ||
            (so->so_state & SS_PROTOREF) || (so->so_qstate & SQ_COMP)) {
                SOCK_UNLOCK(so);
                ACCEPT_UNLOCK();
                return;
        }

        head = so->so_head;
        if (head != NULL) {
                KASSERT((so->so_qstate & SQ_COMP) != 0 ||
                    (so->so_qstate & SQ_INCOMP) != 0,
                    ("sofree: so_head != NULL, but neither SQ_COMP nor "
                    "SQ_INCOMP"));
                KASSERT((so->so_qstate & SQ_COMP) == 0 ||
                    (so->so_qstate & SQ_INCOMP) == 0,
                    ("sofree: so->so_qstate is SQ_COMP and also SQ_INCOMP"));
                TAILQ_REMOVE(&head->so_incomp, so, so_list);
                head->so_incqlen--;
                so->so_qstate &= ~SQ_INCOMP;
                so->so_head = NULL;
        }
        KASSERT((so->so_qstate & SQ_COMP) == 0 &&
            (so->so_qstate & SQ_INCOMP) == 0,
            ("sofree: so_head == NULL, but still SQ_COMP(%d) or SQ_INCOMP(%d)",
            so->so_qstate & SQ_COMP, so->so_qstate & SQ_INCOMP));
        SOCK_UNLOCK(so);
        ACCEPT_UNLOCK();

        SOCKBUF_LOCK(&so->so_snd);
        so->so_snd.sb_flags |= SB_NOINTR;
        (void)sblock(&so->so_snd, M_WAITOK);
        /*
         * socantsendmore_locked() drops the socket buffer mutex so that it
         * can safely perform wakeups.  Re-acquire the mutex before
         * continuing.
         */
        socantsendmore_locked(so);
        SOCKBUF_LOCK(&so->so_snd);
        sbunlock(&so->so_snd);
        sbrelease_locked(&so->so_snd, so);
        SOCKBUF_UNLOCK(&so->so_snd);
        sorflush(so);
        knlist_destroy(&so->so_rcv.sb_sel.si_note);
        knlist_destroy(&so->so_snd.sb_sel.si_note);
        sodealloc(so);
}

/*
 * Close a socket on last file table reference removal.
 * Initiate disconnect if connected.
 * Free socket when disconnect complete.
 *
 * This function will sorele() the socket.  Note that soclose() may be
 * called prior to the ref count reaching zero.  The actual socket
 * structure will not be freed until the ref count reaches zero.
 */
int
soclose(so)
        struct socket *so;
{
        int error = 0;

        KASSERT(!(so->so_state & SS_NOFDREF), ("soclose: SS_NOFDREF on enter"));

        funsetown(&so->so_sigio);
        if (so->so_options & SO_ACCEPTCONN) {
                struct socket *sp;
                ACCEPT_LOCK();
                while ((sp = TAILQ_FIRST(&so->so_incomp)) != NULL) {
                        TAILQ_REMOVE(&so->so_incomp, sp, so_list);
                        so->so_incqlen--;
                        sp->so_qstate &= ~SQ_INCOMP;
                        sp->so_head = NULL;
                        ACCEPT_UNLOCK();
                        soabort(sp);
                        ACCEPT_LOCK();
                }
                while ((sp = TAILQ_FIRST(&so->so_comp)) != NULL) {
                        TAILQ_REMOVE(&so->so_comp, sp, so_list);
                        so->so_qlen--;
                        sp->so_qstate &= ~SQ_COMP;
                        sp->so_head = NULL;
                        ACCEPT_UNLOCK();
                        soabort(sp);
                        ACCEPT_LOCK();
                }
                ACCEPT_UNLOCK();
        }
        if (so->so_state & SS_ISCONNECTED) {
                if ((so->so_state & SS_ISDISCONNECTING) == 0) {
                        error = sodisconnect(so);
                        if (error)
                                goto drop;
                }
                if (so->so_options & SO_LINGER) {
                        if ((so->so_state & SS_ISDISCONNECTING) &&
                            (so->so_state & SS_NBIO))
                                goto drop;
                        while (so->so_state & SS_ISCONNECTED) {
                                error = tsleep(&so->so_timeo,
                                    PSOCK | PCATCH, "soclos", so->so_linger * hz);
                                if (error)
                                        break;
                        }
                }
        }

drop:
        (*so->so_proto->pr_usrreqs->pru_detach)(so);
        ACCEPT_LOCK();
        SOCK_LOCK(so);
        KASSERT((so->so_state & SS_NOFDREF) == 0, ("soclose: NOFDREF"));
        so->so_state |= SS_NOFDREF;
        sorele(so);
        return (error);
}

/*
 * soabort() allows the socket code or protocol code to detach a socket that
 * has been in an incomplete or completed listen queue, but has not yet been
 * accepted.
 *
 * This interface is tricky, because it is called on an unreferenced socket,
 * and must be called only by a thread that has actually removed the socket
 * from the listen queue it was on, or races with other threads are risked.
 *
 * This interface will call into the protocol code, so must not be called
 * with any socket locks held.  Protocols do call it while holding their own
 * recursible protocol mutexes, but this is something that should be subject
 * to review in the future.
 *
 * XXXRW: Why do we maintain a distinction between pru_abort() and
 * pru_detach()?
 */
void
soabort(so)
        struct socket *so;
{

        /*
         * In as much as is possible, assert that no references to this
         * socket are held.  This is not quite the same as asserting that the
         * current thread is responsible for arranging for no references, but
         * is as close as we can get for now.
         */
        KASSERT(so->so_count == 0, ("soabort: so_count"));
        KASSERT((so->so_state & SS_PROTOREF) == 0, ("soabort: SS_PROTOREF"));
        KASSERT(so->so_state & SS_NOFDREF, ("soabort: !SS_NOFDREF"));
        KASSERT((so->so_state & SQ_COMP) == 0, ("soabort: SQ_COMP"));
        KASSERT((so->so_state & SQ_INCOMP) == 0, ("soabort: SQ_INCOMP"));

        (*so->so_proto->pr_usrreqs->pru_abort)(so);
        ACCEPT_LOCK();
        SOCK_LOCK(so);
        sofree(so);
}

int
soaccept(so, nam)
        struct socket *so;
        struct sockaddr **nam;
{
        int error;

        SOCK_LOCK(so);
        KASSERT((so->so_state & SS_NOFDREF) != 0, ("soaccept: !NOFDREF"));
        so->so_state &= ~SS_NOFDREF;
        SOCK_UNLOCK(so);
        error = (*so->so_proto->pr_usrreqs->pru_accept)(so, nam);
        return (error);
}

int
soconnect(so, nam, td)
        struct socket *so;
        struct sockaddr *nam;
        struct thread *td;
{
        int error;

        if (so->so_options & SO_ACCEPTCONN)
                return (EOPNOTSUPP);
        /*
         * If protocol is connection-based, can only connect once.
         * Otherwise, if connected, try to disconnect first.
         * This allows user to disconnect by connecting to, e.g.,
         * a null address.
         */
        if (so->so_state & (SS_ISCONNECTED|SS_ISCONNECTING) &&
            ((so->so_proto->pr_flags & PR_CONNREQUIRED) ||
            (error = sodisconnect(so)))) {
                error = EISCONN;
        } else {
                /*
                 * Prevent accumulated error from previous connection
                 * from biting us.
                 */
                so->so_error = 0;
                error = (*so->so_proto->pr_usrreqs->pru_connect)(so, nam, td);
        }

        return (error);
}

int
soconnect2(so1, so2)
        struct socket *so1;
        struct socket *so2;
{

        return ((*so1->so_proto->pr_usrreqs->pru_connect2)(so1, so2));
}

int
sodisconnect(so)
        struct socket *so;
{
        int error;

        if ((so->so_state & SS_ISCONNECTED) == 0)
                return (ENOTCONN);
        if (so->so_state & SS_ISDISCONNECTING)
                return (EALREADY);
        error = (*so->so_proto->pr_usrreqs->pru_disconnect)(so);
        return (error);
}

#ifdef ZERO_COPY_SOCKETS
struct so_zerocopy_stats{
        int size_ok;
        int align_ok;
        int found_ifp;
};
struct so_zerocopy_stats so_zerocp_stats = {0,0,0};
#include <netinet/in.h>
#include <net/route.h>
#include <netinet/in_pcb.h>
#include <vm/vm.h>
#include <vm/vm_page.h>
#include <vm/vm_object.h>
#endif /*ZERO_COPY_SOCKETS*/

/*
 * sosend_copyin() accepts a uio and prepares an mbuf chain holding part or
 * all of the data referenced by the uio.  If desired, it uses zero-copy.
 * *space will be updated to reflect data copied in.
 *
 * NB: If atomic I/O is requested, the caller must already have checked that
 * space can hold resid bytes.
 *
 * NB: In the event of an error, the caller may need to free the partial
 * chain pointed to by *mpp.  The contents of both *uio and *space may be
 * modified even in the case of an error.
 */
static int
sosend_copyin(struct uio *uio, struct mbuf **retmp, int atomic, long *space,
    int flags)
{
        struct mbuf *m, **mp, *top;
        long len, resid;
        int error;
#ifdef ZERO_COPY_SOCKETS
        int cow_send;
#endif

        *retmp = top = NULL;
        mp = &top;
        len = 0;
        resid = uio->uio_resid;
        error = 0;
        do {
#ifdef ZERO_COPY_SOCKETS
                cow_send = 0;
#endif /* ZERO_COPY_SOCKETS */
                if (resid >= MINCLSIZE) {
#ifdef ZERO_COPY_SOCKETS
                        if (top == NULL) {
                                MGETHDR(m, M_TRYWAIT, MT_DATA);
                                if (m == NULL) {
                                        error = ENOBUFS;
                                        goto out;
                                }
                                m->m_pkthdr.len = 0;
                                m->m_pkthdr.rcvif = NULL; 
                        } else {
                                MGET(m, M_TRYWAIT, MT_DATA);
                                if (m == NULL) {
                                        error = ENOBUFS;
                                        goto out;
                                }
                        }
                        if (so_zero_copy_send &&
                            resid>=PAGE_SIZE &&
                            *space>=PAGE_SIZE &&
                            uio->uio_iov->iov_len>=PAGE_SIZE) {
                                so_zerocp_stats.size_ok++;
                                so_zerocp_stats.align_ok++;
                                cow_send = socow_setup(m, uio);
                                len = cow_send;
                        }
                        if (!cow_send) {
                                MCLGET(m, M_TRYWAIT);
                                if ((m->m_flags & M_EXT) == 0) {
                                        m_free(m);
                                        m = NULL;
                                } else {
                                        len = min(min(MCLBYTES, resid),
                                            *space);
                                }
                        }
#else /* ZERO_COPY_SOCKETS */
                        if (top == NULL) {
                                m = m_getcl(M_TRYWAIT, MT_DATA, M_PKTHDR);
                                m->m_pkthdr.len = 0;
                                m->m_pkthdr.rcvif = NULL;
                        } else
                                m = m_getcl(M_TRYWAIT, MT_DATA, 0);
                        len = min(min(MCLBYTES, resid), *space);
#endif /* ZERO_COPY_SOCKETS */
                } else {
                        if (top == NULL) {
                                m = m_gethdr(M_TRYWAIT, MT_DATA);
                                m->m_pkthdr.len = 0;
                                m->m_pkthdr.rcvif = NULL;

                                len = min(min(MHLEN, resid), *space);
                                /*
                                 * For datagram protocols, leave room
                                 * for protocol headers in first mbuf.
                                 */
                                if (atomic && m && len < MHLEN)
                                        MH_ALIGN(m, len);
                        } else {
                                m = m_get(M_TRYWAIT, MT_DATA);
                                len = min(min(MLEN, resid), *space);
                        }
                }
                if (m == NULL) {
                        error = ENOBUFS;
                        goto out;
                }

                *space -= len;
#ifdef ZERO_COPY_SOCKETS
                if (cow_send)
                        error = 0;
                else
#endif /* ZERO_COPY_SOCKETS */
                error = uiomove(mtod(m, void *), (int)len, uio);
                resid = uio->uio_resid;
                m->m_len = len;
                *mp = m;
                top->m_pkthdr.len += len;
                if (error)
                        goto out;
                mp = &m->m_next;
                if (resid <= 0) {
                        if (flags & MSG_EOR)
                                top->m_flags |= M_EOR;
                        break;
                }
        } while (*space > 0 && atomic);
out:
        *retmp = top;
        return (error);
}

#define SBLOCKWAIT(f)   (((f) & MSG_DONTWAIT) ? M_NOWAIT : M_WAITOK)

int
sosend_dgram(so, addr, uio, top, control, flags, td)
        struct socket *so;
        struct sockaddr *addr;
        struct uio *uio;
        struct mbuf *top;
        struct mbuf *control;
        int flags;
        struct thread *td;
{
        long space, resid;
        int clen = 0, error, dontroute;
        int atomic = sosendallatonce(so) || top;

        KASSERT(so->so_type == SOCK_DGRAM, ("sodgram_send: !SOCK_DGRAM"));
        KASSERT(so->so_proto->pr_flags & PR_ATOMIC,
            ("sodgram_send: !PR_ATOMIC"));

        if (uio != NULL)
                resid = uio->uio_resid;
        else
                resid = top->m_pkthdr.len;
        /*
         * In theory resid should be unsigned.
         * However, space must be signed, as it might be less than 0
         * if we over-committed, and we must use a signed comparison
         * of space and resid.  On the other hand, a negative resid
         * causes us to loop sending 0-length segments to the protocol.
         *
         * Also check to make sure that MSG_EOR isn't used on SOCK_STREAM
         * type sockets since that's an error.
         */
        if (resid < 0) {
                error = EINVAL;
                goto out;
        }

        dontroute =
            (flags & MSG_DONTROUTE) && (so->so_options & SO_DONTROUTE) == 0;
        if (td != NULL)
                td->td_proc->p_stats->p_ru.ru_msgsnd++;
        if (control != NULL)
                clen = control->m_len;

        SOCKBUF_LOCK(&so->so_snd);
        if (so->so_snd.sb_state & SBS_CANTSENDMORE) {
                SOCKBUF_UNLOCK(&so->so_snd);
                error = EPIPE;
                goto out;
        }
        if (so->so_error) {
                error = so->so_error;
                so->so_error = 0;
                SOCKBUF_UNLOCK(&so->so_snd);
                goto out;
        }
        if ((so->so_state & SS_ISCONNECTED) == 0) {
                /*
                 * `sendto' and `sendmsg' is allowed on a connection-
                 * based socket if it supports implied connect.
                 * Return ENOTCONN if not connected and no address is
                 * supplied.
                 */
                if ((so->so_proto->pr_flags & PR_CONNREQUIRED) &&
                    (so->so_proto->pr_flags & PR_IMPLOPCL) == 0) {
                        if ((so->so_state & SS_ISCONFIRMING) == 0 &&
                            !(resid == 0 && clen != 0)) {
                                SOCKBUF_UNLOCK(&so->so_snd);
                                error = ENOTCONN;
                                goto out;
                        }
                } else if (addr == NULL) {
                        if (so->so_proto->pr_flags & PR_CONNREQUIRED)
                                error = ENOTCONN;
                        else
                                error = EDESTADDRREQ;
                        SOCKBUF_UNLOCK(&so->so_snd);
                        goto out;
                }
        }

        /*
         * Do we need MSG_OOB support in SOCK_DGRAM?  Signs here may be a
         * problem and need fixing.
         */
        space = sbspace(&so->so_snd);
        if (flags & MSG_OOB)
                space += 1024;
        space -= clen;
        if (resid > space) {
                error = EMSGSIZE;
                goto out;
        }
        SOCKBUF_UNLOCK(&so->so_snd);
        if (uio == NULL) {
                resid = 0;
                if (flags & MSG_EOR)
                        top->m_flags |= M_EOR;
        } else {
                error = sosend_copyin(uio, &top, atomic, &space, flags);
                if (error)
                        goto out;
                resid = uio->uio_resid;
        }
        KASSERT(resid == 0, ("sosend_dgram: resid != 0"));
        /*
         * XXXRW: Frobbing SO_DONTROUTE here is even worse without sblock
         * than with.
         */
        if (dontroute) {
                SOCK_LOCK(so);
                so->so_options |= SO_DONTROUTE;
                SOCK_UNLOCK(so);
        }
        /*
         * XXX all the SBS_CANTSENDMORE checks previously
         * done could be out of date.  We could have recieved
         * a reset packet in an interrupt or maybe we slept
         * while doing page faults in uiomove() etc. We could
         * probably recheck again inside the locking protection
         * here, but there are probably other places that this
         * also happens.  We must rethink this.
         */
        error = (*so->so_proto->pr_usrreqs->pru_send)(so,
            (flags & MSG_OOB) ? PRUS_OOB :
        /*
         * If the user set MSG_EOF, the protocol
         * understands this flag and nothing left to
         * send then use PRU_SEND_EOF instead of PRU_SEND.
         */
            ((flags & MSG_EOF) &&
             (so->so_proto->pr_flags & PR_IMPLOPCL) &&
             (resid <= 0)) ?
                PRUS_EOF :
                /* If there is more to send set PRUS_MORETOCOME */
                (resid > 0 && space > 0) ? PRUS_MORETOCOME : 0,
                top, addr, control, td);
        if (dontroute) {
                SOCK_LOCK(so);
                so->so_options &= ~SO_DONTROUTE;
                SOCK_UNLOCK(so);
        }
        clen = 0;
        control = NULL;
        top = NULL;
out:
        if (top != NULL)
                m_freem(top);
        if (control != NULL)
                m_freem(control);
        return (error);
}

/*
 * Send on a socket.
 * If send must go all at once and message is larger than
 * send buffering, then hard error.
 * Lock against other senders.
 * If must go all at once and not enough room now, then
 * inform user that this would block and do nothing.
 * Otherwise, if nonblocking, send as much as possible.
 * The data to be sent is described by "uio" if nonzero,
 * otherwise by the mbuf chain "top" (which must be null
 * if uio is not).  Data provided in mbuf chain must be small
 * enough to send all at once.
 *
 * Returns nonzero on error, timeout or signal; callers
 * must check for short counts if EINTR/ERESTART are returned.
 * Data and control buffers are freed on return.
 */
#define snderr(errno)   { error = (errno); goto release; }
int
sosend(so, addr, uio, top, control, flags, td)
        struct socket *so;
        struct sockaddr *addr;
        struct uio *uio;
        struct mbuf *top;
        struct mbuf *control;
        int flags;
        struct thread *td;
{
        long space, resid;
        int clen = 0, error, dontroute;
        int atomic = sosendallatonce(so) || top;

        if (uio != NULL)
                resid = uio->uio_resid;
        else
                resid = top->m_pkthdr.len;
        /*
         * In theory resid should be unsigned.
         * However, space must be signed, as it might be less than 0
         * if we over-committed, and we must use a signed comparison
         * of space and resid.  On the other hand, a negative resid
         * causes us to loop sending 0-length segments to the protocol.
         *
         * Also check to make sure that MSG_EOR isn't used on SOCK_STREAM
         * type sockets since that's an error.
         */
        if (resid < 0 || (so->so_type == SOCK_STREAM && (flags & MSG_EOR))) {
                error = EINVAL;
                goto out;
        }

        dontroute =
            (flags & MSG_DONTROUTE) && (so->so_options & SO_DONTROUTE) == 0 &&
            (so->so_proto->pr_flags & PR_ATOMIC);
        if (td != NULL)
                td->td_proc->p_stats->p_ru.ru_msgsnd++;
        if (control != NULL)
                clen = control->m_len;

        SOCKBUF_LOCK(&so->so_snd);
restart:
        SOCKBUF_LOCK_ASSERT(&so->so_snd);
        error = sblock(&so->so_snd, SBLOCKWAIT(flags));
        if (error)
                goto out_locked;
        do {
                SOCKBUF_LOCK_ASSERT(&so->so_snd);
                if (so->so_snd.sb_state & SBS_CANTSENDMORE)
                        snderr(EPIPE);
                if (so->so_error) {
                        error = so->so_error;
                        so->so_error = 0;
                        goto release;
                }
                if ((so->so_state & SS_ISCONNECTED) == 0) {
                        /*
                         * `sendto' and `sendmsg' is allowed on a connection-
                         * based socket if it supports implied connect.
                         * Return ENOTCONN if not connected and no address is
                         * supplied.
                         */
                        if ((so->so_proto->pr_flags & PR_CONNREQUIRED) &&
                            (so->so_proto->pr_flags & PR_IMPLOPCL) == 0) {
                                if ((so->so_state & SS_ISCONFIRMING) == 0 &&
                                    !(resid == 0 && clen != 0))
                                        snderr(ENOTCONN);
                        } else if (addr == NULL)
                            snderr(so->so_proto->pr_flags & PR_CONNREQUIRED ?
                                   ENOTCONN : EDESTADDRREQ);
                }
                space = sbspace(&so->so_snd);
                if (flags & MSG_OOB)
                        space += 1024;
                if ((atomic && resid > so->so_snd.sb_hiwat) ||
                    clen > so->so_snd.sb_hiwat)
                        snderr(EMSGSIZE);
                if (space < resid + clen &&
                    (atomic || space < so->so_snd.sb_lowat || space < clen)) {
                        if ((so->so_state & SS_NBIO) || (flags & MSG_NBIO))
                                snderr(EWOULDBLOCK);
                        sbunlock(&so->so_snd);
                        error = sbwait(&so->so_snd);
                        if (error)
                                goto out_locked;
                        goto restart;
                }
                SOCKBUF_UNLOCK(&so->so_snd);
                space -= clen;
                do {
                        if (uio == NULL) {
                                resid = 0;
                                if (flags & MSG_EOR)
                                        top->m_flags |= M_EOR;
                        } else {
                                error = sosend_copyin(uio, &top, atomic,
                                    &space, flags);
                                if (error != 0) {
                                        SOCKBUF_LOCK(&so->so_snd);
                                        goto release;
                                }
                                resid = uio->uio_resid;
                        }
                        if (dontroute) {
                                SOCK_LOCK(so);
                                so->so_options |= SO_DONTROUTE;
                                SOCK_UNLOCK(so);
                        }
                        /*
                         * XXX all the SBS_CANTSENDMORE checks previously
                         * done could be out of date.  We could have recieved
                         * a reset packet in an interrupt or maybe we slept
                         * while doing page faults in uiomove() etc. We could
                         * probably recheck again inside the locking protection
                         * here, but there are probably other places that this
                         * also happens.  We must rethink this.
                         */
                        error = (*so->so_proto->pr_usrreqs->pru_send)(so,
                            (flags & MSG_OOB) ? PRUS_OOB :
                        /*
                         * If the user set MSG_EOF, the protocol
                         * understands this flag and nothing left to
                         * send then use PRU_SEND_EOF instead of PRU_SEND.
                         */
                            ((flags & MSG_EOF) &&
                             (so->so_proto->pr_flags & PR_IMPLOPCL) &&
                             (resid <= 0)) ?
                                PRUS_EOF :
                        /* If there is more to send set PRUS_MORETOCOME */
                            (resid > 0 && space > 0) ? PRUS_MORETOCOME : 0,
                            top, addr, control, td);
                        if (dontroute) {
                                SOCK_LOCK(so);
                                so->so_options &= ~SO_DONTROUTE;
                                SOCK_UNLOCK(so);
                        }
                        clen = 0;
                        control = NULL;
                        top = NULL;
                        if (error) {
                                SOCKBUF_LOCK(&so->so_snd);
                                goto release;
                        }
                } while (resid && space > 0);
                SOCKBUF_LOCK(&so->so_snd);
        } while (resid);

release:
        SOCKBUF_LOCK_ASSERT(&so->so_snd);
        sbunlock(&so->so_snd);
out_locked:
        SOCKBUF_LOCK_ASSERT(&so->so_snd);
        SOCKBUF_UNLOCK(&so->so_snd);
out:
        if (top != NULL)
                m_freem(top);
        if (control != NULL)
                m_freem(control);
        return (error);
}
#undef snderr

/*
 * The part of soreceive() that implements reading non-inline out-of-band
 * data from a socket.  For more complete comments, see soreceive(), from
 * which this code originated.
 *
 * Note that soreceive_rcvoob(), unlike the remainder of soreceive(), is
 * unable to return an mbuf chain to the caller.
 */
static int
soreceive_rcvoob(so, uio, flags)
        struct socket *so;
        struct uio *uio;
        int flags;
{
        struct protosw *pr = so->so_proto;
        struct mbuf *m;
        int error;

        KASSERT(flags & MSG_OOB, ("soreceive_rcvoob: (flags & MSG_OOB) == 0"));

        m = m_get(M_TRYWAIT, MT_DATA);
        if (m == NULL)
                return (ENOBUFS);
        error = (*pr->pr_usrreqs->pru_rcvoob)(so, m, flags & MSG_PEEK);
        if (error)
                goto bad;
        do {
#ifdef ZERO_COPY_SOCKETS
                if (so_zero_copy_receive) {
                        int disposable;

                        if ((m->m_flags & M_EXT)
                         && (m->m_ext.ext_type == EXT_DISPOSABLE))
                                disposable = 1;
                        else
                                disposable = 0;

                        error = uiomoveco(mtod(m, void *),
                                          min(uio->uio_resid, m->m_len),
                                          uio, disposable);
                } else
#endif /* ZERO_COPY_SOCKETS */
                error = uiomove(mtod(m, void *),
                    (int) min(uio->uio_resid, m->m_len), uio);
                m = m_free(m);
        } while (uio->uio_resid && error == 0 && m);
bad:
        if (m != NULL)
                m_freem(m);
        return (error);
}

/*
 * Following replacement or removal of the first mbuf on the first mbuf chain
 * of a socket buffer, push necessary state changes back into the socket
 * buffer so that other consumers see the values consistently.  'nextrecord'
 * is the callers locally stored value of the original value of
 * sb->sb_mb->m_nextpkt which must be restored when the lead mbuf changes.
 * NOTE: 'nextrecord' may be NULL.
 */
static __inline void
sockbuf_pushsync(struct sockbuf *sb, struct mbuf *nextrecord)
{

        SOCKBUF_LOCK_ASSERT(sb);
        /*
         * First, update for the new value of nextrecord.  If necessary, make
         * it the first record.
         */
        if (sb->sb_mb != NULL)
                sb->sb_mb->m_nextpkt = nextrecord;
        else
                sb->sb_mb = nextrecord;

        /*
         * Now update any dependent socket buffer fields to reflect the new
         * state.  This is an expanded inline of SB_EMPTY_FIXUP(), with the
         * addition of a second clause that takes care of the case where
         * sb_mb has been updated, but remains the last record.
         */
        if (sb->sb_mb == NULL) {
                sb->sb_mbtail = NULL;
                sb->sb_lastrecord = NULL;
        } else if (sb->sb_mb->m_nextpkt == NULL)
                sb->sb_lastrecord = sb->sb_mb;
}


/*
 * Implement receive operations on a socket.
 * We depend on the way that records are added to the sockbuf
 * by sbappend*.  In particular, each record (mbufs linked through m_next)
 * must begin with an address if the protocol so specifies,
 * followed by an optional mbuf or mbufs containing ancillary data,
 * and then zero or more mbufs of data.
 * In order to avoid blocking network interrupts for the entire time here,
 * we splx() while doing the actual copy to user space.
 * Although the sockbuf is locked, new data may still be appended,
 * and thus we must maintain consistency of the sockbuf during that time.
 *
 * The caller may receive the data as a single mbuf chain by supplying
 * an mbuf **mp0 for use in returning the chain.  The uio is then used
 * only for the count in uio_resid.
 */
int
soreceive(so, psa, uio, mp0, controlp, flagsp)
        struct socket *so;
        struct sockaddr **psa;
        struct uio *uio;
        struct mbuf **mp0;
        struct mbuf **controlp;
        int *flagsp;
{
        struct mbuf *m, **mp;
        int flags, len, error, offset;
        struct protosw *pr = so->so_proto;
        struct mbuf *nextrecord;
        int moff, type = 0;
        int orig_resid = uio->uio_resid;

        mp = mp0;
        if (psa != NULL)
                *psa = NULL;
        if (controlp != NULL)
                *controlp = NULL;
        if (flagsp != NULL)
                flags = *flagsp &~ MSG_EOR;
        else
                flags = 0;
        if (flags & MSG_OOB)
                return (soreceive_rcvoob(so, uio, flags));
        if (mp != NULL)
                *mp = NULL;
        if ((pr->pr_flags & PR_WANTRCVD) && (so->so_state & SS_ISCONFIRMING)
            && uio->uio_resid)
                (*pr->pr_usrreqs->pru_rcvd)(so, 0);

        SOCKBUF_LOCK(&so->so_rcv);
restart:
        SOCKBUF_LOCK_ASSERT(&so->so_rcv);
        error = sblock(&so->so_rcv, SBLOCKWAIT(flags));
        if (error)
                goto out;

        m = so->so_rcv.sb_mb;
        /*
         * If we have less data than requested, block awaiting more
         * (subject to any timeout) if:
         *   1. the current count is less than the low water mark, or
         *   2. MSG_WAITALL is set, and it is possible to do the entire
         *      receive operation at once if we block (resid <= hiwat).
         *   3. MSG_DONTWAIT is not set
         * If MSG_WAITALL is set but resid is larger than the receive buffer,
         * we have to do the receive in sections, and thus risk returning
         * a short count if a timeout or signal occurs after we start.
         */
        if (m == NULL || (((flags & MSG_DONTWAIT) == 0 &&
            so->so_rcv.sb_cc < uio->uio_resid) &&
            (so->so_rcv.sb_cc < so->so_rcv.sb_lowat ||
            ((flags & MSG_WAITALL) && uio->uio_resid <= so->so_rcv.sb_hiwat)) &&
            m->m_nextpkt == NULL && (pr->pr_flags & PR_ATOMIC) == 0)) {
                KASSERT(m != NULL || !so->so_rcv.sb_cc,
                    ("receive: m == %p so->so_rcv.sb_cc == %u",
                    m, so->so_rcv.sb_cc));
                if (so->so_error) {
                        if (m != NULL)
                                goto dontblock;
                        error = so->so_error;
                        if ((flags & MSG_PEEK) == 0)
                                so->so_error = 0;
                        goto release;
                }
                SOCKBUF_LOCK_ASSERT(&so->so_rcv);
                if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
                        if (m)
                                goto dontblock;
                        else
                                goto release;
                }
                for (; m != NULL; m = m->m_next)
                        if (m->m_type == MT_OOBDATA  || (m->m_flags & M_EOR)) {
                                m = so->so_rcv.sb_mb;
                                goto dontblock;
                        }
                if ((so->so_state & (SS_ISCONNECTED|SS_ISCONNECTING)) == 0 &&
                    (so->so_proto->pr_flags & PR_CONNREQUIRED)) {
                        error = ENOTCONN;
                        goto release;
                }
                if (uio->uio_resid == 0)
                        goto release;
                if ((so->so_state & SS_NBIO) ||
                    (flags & (MSG_DONTWAIT|MSG_NBIO))) {
                        error = EWOULDBLOCK;
                        goto release;
                }
                SBLASTRECORDCHK(&so->so_rcv);
                SBLASTMBUFCHK(&so->so_rcv);
                sbunlock(&so->so_rcv);
                error = sbwait(&so->so_rcv);
                if (error)
                        goto out;
                goto restart;
        }
dontblock:
        /*
         * From this point onward, we maintain 'nextrecord' as a cache of the
         * pointer to the next record in the socket buffer.  We must keep the
         * various socket buffer pointers and local stack versions of the
         * pointers in sync, pushing out modifications before dropping the
         * socket buffer mutex, and re-reading them when picking it up.
         *
         * Otherwise, we will race with the network stack appending new data
         * or records onto the socket buffer by using inconsistent/stale
         * versions of the field, possibly resulting in socket buffer
         * corruption.
         *
         * By holding the high-level sblock(), we prevent simultaneous
         * readers from pulling off the front of the socket buffer.
         */
        SOCKBUF_LOCK_ASSERT(&so->so_rcv);
        if (uio->uio_td)
                uio->uio_td->td_proc->p_stats->p_ru.ru_msgrcv++;
        KASSERT(m == so->so_rcv.sb_mb, ("soreceive: m != so->so_rcv.sb_mb"));
        SBLASTRECORDCHK(&so->so_rcv);
        SBLASTMBUFCHK(&so->so_rcv);
        nextrecord = m->m_nextpkt;
        if (pr->pr_flags & PR_ADDR) {
                KASSERT(m->m_type == MT_SONAME,
                    ("m->m_type == %d", m->m_type));
                orig_resid = 0;
                if (psa != NULL)
                        *psa = sodupsockaddr(mtod(m, struct sockaddr *),
                            M_NOWAIT);
                if (flags & MSG_PEEK) {
                        m = m->m_next;
                } else {
                        sbfree(&so->so_rcv, m);
                        so->so_rcv.sb_mb = m_free(m);
                        m = so->so_rcv.sb_mb;
                        sockbuf_pushsync(&so->so_rcv, nextrecord);
                }
        }

        /*
         * Process one or more MT_CONTROL mbufs present before any data mbufs
         * in the first mbuf chain on the socket buffer.  If MSG_PEEK, we
         * just copy the data; if !MSG_PEEK, we call into the protocol to
         * perform externalization (or freeing if controlp == NULL).
         */
        if (m != NULL && m->m_type == MT_CONTROL) {
                struct mbuf *cm = NULL, *cmn;
                struct mbuf **cme = &cm;

                do {
                        if (flags & MSG_PEEK) {
                                if (controlp != NULL) {
                                        *controlp = m_copy(m, 0, m->m_len);
                                        controlp = &(*controlp)->m_next;
                                }
                                m = m->m_next;
                        } else {
                                sbfree(&so->so_rcv, m);
                                so->so_rcv.sb_mb = m->m_next;
                                m->m_next = NULL;
                                *cme = m;
                                cme = &(*cme)->m_next;
                                m = so->so_rcv.sb_mb;
                        }
                } while (m != NULL && m->m_type == MT_CONTROL);
                if ((flags & MSG_PEEK) == 0)
                        sockbuf_pushsync(&so->so_rcv, nextrecord);
                while (cm != NULL) {
                        cmn = cm->m_next;
                        cm->m_next = NULL;
                        if (pr->pr_domain->dom_externalize != NULL) {
                                SOCKBUF_UNLOCK(&so->so_rcv);
                                error = (*pr->pr_domain->dom_externalize)
                                    (cm, controlp);
                                SOCKBUF_LOCK(&so->so_rcv);
                        } else if (controlp != NULL)
                                *controlp = cm;
                        else
                                m_freem(cm);
                        if (controlp != NULL) {
                                orig_resid = 0;
                                while (*controlp != NULL)
                                        controlp = &(*controlp)->m_next;
                        }
                        cm = cmn;
                }
                if (so->so_rcv.sb_mb)
                        nextrecord = so->so_rcv.sb_mb->m_nextpkt;
                else
                        nextrecord = NULL;
                orig_resid = 0;
        }
        if (m != NULL) {
                if ((flags & MSG_PEEK) == 0) {
                        KASSERT(m->m_nextpkt == nextrecord,
                            ("soreceive: post-control, nextrecord !sync"));
                        if (nextrecord == NULL) {
                                KASSERT(so->so_rcv.sb_mb == m,
                                    ("soreceive: post-control, sb_mb!=m"));
                                KASSERT(so->so_rcv.sb_lastrecord == m,
                                    ("soreceive: post-control, lastrecord!=m"));
                        }
                }
                type = m->m_type;
                if (type == MT_OOBDATA)
                        flags |= MSG_OOB;
        } else {
                if ((flags & MSG_PEEK) == 0) {
                        KASSERT(so->so_rcv.sb_mb == nextrecord,
                            ("soreceive: sb_mb != nextrecord"));
                        if (so->so_rcv.sb_mb == NULL) {
                                KASSERT(so->so_rcv.sb_lastrecord == NULL,
                                    ("soreceive: sb_lastercord != NULL"));
                        }
                }
        }
        SOCKBUF_LOCK_ASSERT(&so->so_rcv);
        SBLASTRECORDCHK(&so->so_rcv);
        SBLASTMBUFCHK(&so->so_rcv);

        /*
         * Now continue to read any data mbufs off of the head of the socket
         * buffer until the read request is satisfied.  Note that 'type' is
         * used to store the type of any mbuf reads that have happened so far
         * such that soreceive() can stop reading if the type changes, which
         * causes soreceive() to return only one of regular data and inline
         * out-of-band data in a single socket receive operation.
         */
        moff = 0;
        offset = 0;
        while (m != NULL && uio->uio_resid > 0 && error == 0) {
                /*
                 * If the type of mbuf has changed since the last mbuf
                 * examined ('type'), end the receive operation.
                 */
                SOCKBUF_LOCK_ASSERT(&so->so_rcv);
                if (m->m_type == MT_OOBDATA) {
                        if (type != MT_OOBDATA)
                                break;
                } else if (type == MT_OOBDATA)
                        break;
                else
                    KASSERT(m->m_type == MT_DATA,
                        ("m->m_type == %d", m->m_type));
                so->so_rcv.sb_state &= ~SBS_RCVATMARK;
                len = uio->uio_resid;
                if (so->so_oobmark && len > so->so_oobmark - offset)
                        len = so->so_oobmark - offset;
                if (len > m->m_len - moff)
                        len = m->m_len - moff;
                /*
                 * If mp is set, just pass back the mbufs.
                 * Otherwise copy them out via the uio, then free.
                 * Sockbuf must be consistent here (points to current mbuf,
                 * it points to next record) when we drop priority;
                 * we must note any additions to the sockbuf when we
                 * block interrupts again.
                 */
                if (mp == NULL) {
                        SOCKBUF_LOCK_ASSERT(&so->so_rcv);
                        SBLASTRECORDCHK(&so->so_rcv);
                        SBLASTMBUFCHK(&so->so_rcv);
                        SOCKBUF_UNLOCK(&so->so_rcv);
#ifdef ZERO_COPY_SOCKETS
                        if (so_zero_copy_receive) {
                                int disposable;

                                if ((m->m_flags & M_EXT)
                                 && (m->m_ext.ext_type == EXT_DISPOSABLE))
                                        disposable = 1;
                                else
                                        disposable = 0;

                                error = uiomoveco(mtod(m, char *) + moff,
                                                  (int)len, uio,
                                                  disposable);
                        } else
#endif /* ZERO_COPY_SOCKETS */
                        error = uiomove(mtod(m, char *) + moff, (int)len, uio);
                        SOCKBUF_LOCK(&so->so_rcv);
                        if (error)
                                goto release;
                } else
                        uio->uio_resid -= len;
                SOCKBUF_LOCK_ASSERT(&so->so_rcv);
                if (len == m->m_len - moff) {
                        if (m->m_flags & M_EOR)
                                flags |= MSG_EOR;
                        if (flags & MSG_PEEK) {
                                m = m->m_next;
                                moff = 0;
                        } else {
                                nextrecord = m->m_nextpkt;
                                sbfree(&so->so_rcv, m);
                                if (mp != NULL) {
                                        *mp = m;
                                        mp = &m->m_next;
                                        so->so_rcv.sb_mb = m = m->m_next;
                                        *mp = NULL;
                                } else {
                                        so->so_rcv.sb_mb = m_free(m);
                                        m = so->so_rcv.sb_mb;
                                }
                                sockbuf_pushsync(&so->so_rcv, nextrecord);
                                SBLASTRECORDCHK(&so->so_rcv);
                                SBLASTMBUFCHK(&so->so_rcv);
                        }
                } else {
                        if (flags & MSG_PEEK)
                                moff += len;
                        else {
                                if (mp != NULL) {
                                        int copy_flag;

                                        if (flags & MSG_DONTWAIT)
                                                copy_flag = M_DONTWAIT;
                                        else
                                                copy_flag = M_TRYWAIT;
                                        if (copy_flag == M_TRYWAIT)
                                                SOCKBUF_UNLOCK(&so->so_rcv);
                                        *mp = m_copym(m, 0, len, copy_flag);
                                        if (copy_flag == M_TRYWAIT)
                                                SOCKBUF_LOCK(&so->so_rcv);
                                        if (*mp == NULL) {
                                                /*
                                                 * m_copym() couldn't allocate an mbuf. 
                                                 * Adjust uio_resid back (it was adjusted 
                                                 * down by len bytes, which we didn't end 
                                                 * up "copying" over).
                                                 */
                                                uio->uio_resid += len;
                                                break;
                                        }
                                }
                                m->m_data += len;
                                m->m_len -= len;
                                so->so_rcv.sb_cc -= len;
                        }
                }
                SOCKBUF_LOCK_ASSERT(&so->so_rcv);
                if (so->so_oobmark) {
                        if ((flags & MSG_PEEK) == 0) {
                                so->so_oobmark -= len;
                                if (so->so_oobmark == 0) {
                                        so->so_rcv.sb_state |= SBS_RCVATMARK;
                                        break;
                                }
                        } else {
                                offset += len;
                                if (offset == so->so_oobmark)
                                        break;
                        }
                }
                if (flags & MSG_EOR)
                        break;
                /*
                 * If the MSG_WAITALL flag is set (for non-atomic socket),
                 * we must not quit until "uio->uio_resid == 0" or an error
                 * termination.  If a signal/timeout occurs, return
                 * with a short count but without error.
                 * Keep sockbuf locked against other readers.
                 */
                while (flags & MSG_WAITALL && m == NULL && uio->uio_resid > 0 &&
                    !sosendallatonce(so) && nextrecord == NULL) {
                        SOCKBUF_LOCK_ASSERT(&so->so_rcv);
                        if (so->so_error || so->so_rcv.sb_state & SBS_CANTRCVMORE)
                                break;
                        /*
                         * Notify the protocol that some data has been
                         * drained before blocking.
                         */
                        if (pr->pr_flags & PR_WANTRCVD) {
                                SOCKBUF_UNLOCK(&so->so_rcv);
                                (*pr->pr_usrreqs->pru_rcvd)(so, flags);
                                SOCKBUF_LOCK(&so->so_rcv);
                        }
                        SBLASTRECORDCHK(&so->so_rcv);
                        SBLASTMBUFCHK(&so->so_rcv);
                        error = sbwait(&so->so_rcv);
                        if (error)
                                goto release;
                        m = so->so_rcv.sb_mb;
                        if (m != NULL)
                                nextrecord = m->m_nextpkt;
                }
        }

        SOCKBUF_LOCK_ASSERT(&so->so_rcv);
        if (m != NULL && pr->pr_flags & PR_ATOMIC) {
                flags |= MSG_TRUNC;
                if ((flags & MSG_PEEK) == 0)
                        (void) sbdroprecord_locked(&so->so_rcv);
        }
        if ((flags & MSG_PEEK) == 0) {
                if (m == NULL) {
                        /*
                         * First part is an inline SB_EMPTY_FIXUP().  Second
                         * part makes sure sb_lastrecord is up-to-date if
                         * there is still data in the socket buffer.
                         */
                        so->so_rcv.sb_mb = nextrecord;
                        if (so->so_rcv.sb_mb == NULL) {
                                so->so_rcv.sb_mbtail = NULL;
                                so->so_rcv.sb_lastrecord = NULL;
                        } else if (nextrecord->m_nextpkt == NULL)
                                so->so_rcv.sb_lastrecord = nextrecord;
                }
                SBLASTRECORDCHK(&so->so_rcv);
                SBLASTMBUFCHK(&so->so_rcv);
                /*
                 * If soreceive() is being done from the socket callback, then 
                 * don't need to generate ACK to peer to update window, since 
                 * ACK will be generated on return to TCP.
                 */
                if (!(flags & MSG_SOCALLBCK) && 
                    (pr->pr_flags & PR_WANTRCVD)) {
                        SOCKBUF_UNLOCK(&so->so_rcv);
                        (*pr->pr_usrreqs->pru_rcvd)(so, flags);
                        SOCKBUF_LOCK(&so->so_rcv);
                }
        }
        SOCKBUF_LOCK_ASSERT(&so->so_rcv);
        if (orig_resid == uio->uio_resid && orig_resid &&
            (flags & MSG_EOR) == 0 && (so->so_rcv.sb_state & SBS_CANTRCVMORE) == 0) {
                sbunlock(&so->so_rcv);
                goto restart;
        }

        if (flagsp != NULL)
                *flagsp |= flags;
release:
        SOCKBUF_LOCK_ASSERT(&so->so_rcv);
        sbunlock(&so->so_rcv);
out:
        SOCKBUF_LOCK_ASSERT(&so->so_rcv);
        SOCKBUF_UNLOCK(&so->so_rcv);
        return (error);
}

int
soshutdown(so, how)
        struct socket *so;
        int how;
{
        struct protosw *pr = so->so_proto;

        if (!(how == SHUT_RD || how == SHUT_WR || how == SHUT_RDWR))
                return (EINVAL);

        if (how != SHUT_WR)
                sorflush(so);
        if (how != SHUT_RD)
                return ((*pr->pr_usrreqs->pru_shutdown)(so));
        return (0);
}

void
sorflush(so)
        struct socket *so;
{
        struct sockbuf *sb = &so->so_rcv;
        struct protosw *pr = so->so_proto;
        struct sockbuf asb;

        /*
         * XXXRW: This is quite ugly.  Previously, this code made a copy of
         * the socket buffer, then zero'd the original to clear the buffer
         * fields.  However, with mutexes in the socket buffer, this causes
         * problems.  We only clear the zeroable bits of the original;
         * however, we have to initialize and destroy the mutex in the copy
         * so that dom_dispose() and sbrelease() can lock t as needed.
         */
        SOCKBUF_LOCK(sb);
        sb->sb_flags |= SB_NOINTR;
        (void) sblock(sb, M_WAITOK);
        /*
         * socantrcvmore_locked() drops the socket buffer mutex so that it
         * can safely perform wakeups.  Re-acquire the mutex before
         * continuing.
         */
        socantrcvmore_locked(so);
        SOCKBUF_LOCK(sb);
        sbunlock(sb);
        /*
         * Invalidate/clear most of the sockbuf structure, but leave
         * selinfo and mutex data unchanged.
         */
        bzero(&asb, offsetof(struct sockbuf, sb_startzero));
        bcopy(&sb->sb_startzero, &asb.sb_startzero,
            sizeof(*sb) - offsetof(struct sockbuf, sb_startzero));
        bzero(&sb->sb_startzero,
            sizeof(*sb) - offsetof(struct sockbuf, sb_startzero));
        SOCKBUF_UNLOCK(sb);

        SOCKBUF_LOCK_INIT(&asb, "so_rcv");
        if (pr->pr_flags & PR_RIGHTS && pr->pr_domain->dom_dispose != NULL)
                (*pr->pr_domain->dom_dispose)(asb.sb_mb);
        sbrelease(&asb, so);
        SOCKBUF_LOCK_DESTROY(&asb);
}

/*
 * Perhaps this routine, and sooptcopyout(), below, ought to come in
 * an additional variant to handle the case where the option value needs
 * to be some kind of integer, but not a specific size.
 * In addition to their use here, these functions are also called by the
 * protocol-level pr_ctloutput() routines.
 */
int
sooptcopyin(sopt, buf, len, minlen)
        struct  sockopt *sopt;
        void    *buf;
        size_t  len;
        size_t  minlen;
{
        size_t  valsize;

        /*
         * If the user gives us more than we wanted, we ignore it,
         * but if we don't get the minimum length the caller
         * wants, we return EINVAL.  On success, sopt->sopt_valsize
         * is set to however much we actually retrieved.
         */
        if ((valsize = sopt->sopt_valsize) < minlen)
                return EINVAL;
        if (valsize > len)
                sopt->sopt_valsize = valsize = len;

        if (sopt->sopt_td != NULL)
                return (copyin(sopt->sopt_val, buf, valsize));

        bcopy(sopt->sopt_val, buf, valsize);
        return (0);
}

/*
 * Kernel version of setsockopt(2)/
 * XXX: optlen is size_t, not socklen_t
 */
int
so_setsockopt(struct socket *so, int level, int optname, void *optval,
    size_t optlen)
{
        struct sockopt sopt;

        sopt.sopt_level = level;
        sopt.sopt_name = optname;
        sopt.sopt_dir = SOPT_SET;
        sopt.sopt_val = optval;
        sopt.sopt_valsize = optlen;
        sopt.sopt_td = NULL;
        return (sosetopt(so, &sopt));
}

int
sosetopt(so, sopt)
        struct socket *so;
        struct sockopt *sopt;
{
        int     error, optval;
        struct  linger l;
        struct  timeval tv;
        u_long  val;
#ifdef MAC
        struct mac extmac;
#endif

        error = 0;
        if (sopt->sopt_level != SOL_SOCKET) {
                if (so->so_proto && so->so_proto->pr_ctloutput)
                        return ((*so->so_proto->pr_ctloutput)
                                  (so, sopt));
                error = ENOPROTOOPT;
        } else {
                switch (sopt->sopt_name) {
#ifdef INET
                case SO_ACCEPTFILTER:
                        error = do_setopt_accept_filter(so, sopt);
                        if (error)
                                goto bad;
                        break;
#endif
                case SO_LINGER:
                        error = sooptcopyin(sopt, &l, sizeof l, sizeof l);
                        if (error)
                                goto bad;

                        SOCK_LOCK(so);
                        so->so_linger = l.l_linger;
                        if (l.l_onoff)
                                so->so_options |= SO_LINGER;
                        else
                                so->so_options &= ~SO_LINGER;
                        SOCK_UNLOCK(so);
                        break;

                case SO_DEBUG:
                case SO_KEEPALIVE:
                case SO_DONTROUTE:
                case SO_USELOOPBACK:
                case SO_BROADCAST:
                case SO_REUSEADDR:
                case SO_REUSEPORT:
                case SO_OOBINLINE:
                case SO_TIMESTAMP:
                case SO_BINTIME:
                case SO_NOSIGPIPE:
                        error = sooptcopyin(sopt, &optval, sizeof optval,
                                            sizeof optval);
                        if (error)
                                goto bad;
                        SOCK_LOCK(so);
                        if (optval)
                                so->so_options |= sopt->sopt_name;
                        else
                                so->so_options &= ~sopt->sopt_name;
                        SOCK_UNLOCK(so);
                        break;

                case SO_SNDBUF:
                case SO_RCVBUF:
                case SO_SNDLOWAT:
                case SO_RCVLOWAT:
                        error = sooptcopyin(sopt, &optval, sizeof optval,
                                            sizeof optval);
                        if (error)
                                goto bad;

                        /*
                         * Values < 1 make no sense for any of these
                         * options, so disallow them.
                         */
                        if (optval < 1) {
                                error = EINVAL;
                                goto bad;
                        }

                        switch (sopt->sopt_name) {
                        case SO_SNDBUF:
                        case SO_RCVBUF:
                                if (sbreserve(sopt->sopt_name == SO_SNDBUF ?
                                    &so->so_snd : &so->so_rcv, (u_long)optval,
                                    so, curthread) == 0) {
                                        error = ENOBUFS;
                                        goto bad;
                                }
                                break;

                        /*
                         * Make sure the low-water is never greater than
                         * the high-water.
                         */
                        case SO_SNDLOWAT:
                                SOCKBUF_LOCK(&so->so_snd);
                                so->so_snd.sb_lowat =
                                    (optval > so->so_snd.sb_hiwat) ?
                                    so->so_snd.sb_hiwat : optval;
                                SOCKBUF_UNLOCK(&so->so_snd);
                                break;
                        case SO_RCVLOWAT:
                                SOCKBUF_LOCK(&so->so_rcv);
                                so->so_rcv.sb_lowat =
                                    (optval > so->so_rcv.sb_hiwat) ?
                                    so->so_rcv.sb_hiwat : optval;
                                SOCKBUF_UNLOCK(&so->so_rcv);
                                break;
                        }
                        break;

                case SO_SNDTIMEO:
                case SO_RCVTIMEO:
#ifdef COMPAT_IA32
                        if (curthread->td_proc->p_sysent == &ia32_freebsd_sysvec) {
                                struct timeval32 tv32;

                                error = sooptcopyin(sopt, &tv32, sizeof tv32,
                                    sizeof tv32);
                                CP(tv32, tv, tv_sec);
                                CP(tv32, tv, tv_usec);
                        } else
#endif
                                error = sooptcopyin(sopt, &tv, sizeof tv,
                                    sizeof tv);
                        if (error)
                                goto bad;

                        /* assert(hz > 0); */
                        if (tv.tv_sec < 0 || tv.tv_sec > INT_MAX / hz ||
                            tv.tv_usec < 0 || tv.tv_usec >= 1000000) {
                                error = EDOM;
                                goto bad;
                        }
                        /* assert(tick > 0); */
                        /* assert(ULONG_MAX - INT_MAX >= 1000000); */
                        val = (u_long)(tv.tv_sec * hz) + tv.tv_usec / tick;
                        if (val > INT_MAX) {
                                error = EDOM;
                                goto bad;
                        }
                        if (val == 0 && tv.tv_usec != 0)
                                val = 1;

                        switch (sopt->sopt_name) {
                        case SO_SNDTIMEO:
                                so->so_snd.sb_timeo = val;
                                break;
                        case SO_RCVTIMEO:
                                so->so_rcv.sb_timeo = val;
                                break;
                        }
                        break;

                case SO_LABEL:
#ifdef MAC
                        error = sooptcopyin(sopt, &extmac, sizeof extmac,
                            sizeof extmac);
                        if (error)
                                goto bad;
                        error = mac_setsockopt_label(sopt->sopt_td->td_ucred,
                            so, &extmac);
#else
                        error = EOPNOTSUPP;
#endif
                        break;

                default:
                        error = ENOPROTOOPT;
                        break;
                }
                if (error == 0 && so->so_proto != NULL &&
                    so->so_proto->pr_ctloutput != NULL) {
                        (void) ((*so->so_proto->pr_ctloutput)
                                  (so, sopt));
                }
        }
bad:
        return (error);
}

/* Helper routine for getsockopt */
int
sooptcopyout(struct sockopt *sopt, const void *buf, size_t len)
{
        int     error;
        size_t  valsize;

        error = 0;

        /*
         * Documented get behavior is that we always return a value,
         * possibly truncated to fit in the user's buffer.
         * Traditional behavior is that we always tell the user
         * precisely how much we copied, rather than something useful
         * like the total amount we had available for her.
         * Note that this interface is not idempotent; the entire answer must
         * generated ahead of time.
         */
        valsize = min(len, sopt->sopt_valsize);
        sopt->sopt_valsize = valsize;
        if (sopt->sopt_val != NULL) {
                if (sopt->sopt_td != NULL)
                        error = copyout(buf, sopt->sopt_val, valsize);
                else
                        bcopy(buf, sopt->sopt_val, valsize);
        }
        return (error);
}

int
sogetopt(so, sopt)
        struct socket *so;
        struct sockopt *sopt;
{
        int     error, optval;
        struct  linger l;
        struct  timeval tv;
#ifdef MAC
        struct mac extmac;
#endif

        error = 0;
        if (sopt->sopt_level != SOL_SOCKET) {
                if (so->so_proto && so->so_proto->pr_ctloutput) {
                        return ((*so->so_proto->pr_ctloutput)
                                  (so, sopt));
                } else
                        return (ENOPROTOOPT);
        } else {
                switch (sopt->sopt_name) {
#ifdef INET
                case SO_ACCEPTFILTER:
                        error = do_getopt_accept_filter(so, sopt);
                        break;
#endif
                case SO_LINGER:
                        SOCK_LOCK(so);
                        l.l_onoff = so->so_options & SO_LINGER;
                        l.l_linger = so->so_linger;
                        SOCK_UNLOCK(so);
                        error = sooptcopyout(sopt, &l, sizeof l);
                        break;

                case SO_USELOOPBACK:
                case SO_DONTROUTE:
                case SO_DEBUG:
                case SO_KEEPALIVE:
                case SO_REUSEADDR:
                case SO_REUSEPORT:
                case SO_BROADCAST:
                case SO_OOBINLINE:
                case SO_ACCEPTCONN:
                case SO_TIMESTAMP:
                case SO_BINTIME:
                case SO_NOSIGPIPE:
                        optval = so->so_options & sopt->sopt_name;
integer:
                        error = sooptcopyout(sopt, &optval, sizeof optval);
                        break;

                case SO_TYPE:
                        optval = so->so_type;
                        goto integer;

                case SO_ERROR:
                        optval = so->so_error;
                        so->so_error = 0;
                        goto integer;

                case SO_SNDBUF:
                        optval = so->so_snd.sb_hiwat;
                        goto integer;

                case SO_RCVBUF:
                        optval = so->so_rcv.sb_hiwat;
                        goto integer;

                case SO_SNDLOWAT:
                        optval = so->so_snd.sb_lowat;
                        goto integer;

                case SO_RCVLOWAT:
                        optval = so->so_rcv.sb_lowat;
                        goto integer;

                case SO_SNDTIMEO:
                case SO_RCVTIMEO:
                        optval = (sopt->sopt_name == SO_SNDTIMEO ?
                                  so->so_snd.sb_timeo : so->so_rcv.sb_timeo);

                        tv.tv_sec = optval / hz;
                        tv.tv_usec = (optval % hz) * tick;
#ifdef COMPAT_IA32
                        if (curthread->td_proc->p_sysent == &ia32_freebsd_sysvec) {
                                struct timeval32 tv32;

                                CP(tv, tv32, tv_sec);
                                CP(tv, tv32, tv_usec);
                                error = sooptcopyout(sopt, &tv32, sizeof tv32);
                        } else
#endif
                                error = sooptcopyout(sopt, &tv, sizeof tv);
                        break;

                case SO_LABEL:
#ifdef MAC
                        error = sooptcopyin(sopt, &extmac, sizeof(extmac),
                            sizeof(extmac));
                        if (error)
                                return (error);
                        error = mac_getsockopt_label(sopt->sopt_td->td_ucred,
                            so, &extmac);
                        if (error)
                                return (error);
                        error = sooptcopyout(sopt, &extmac, sizeof extmac);
#else
                        error = EOPNOTSUPP;
#endif
                        break;

                case SO_PEERLABEL:
#ifdef MAC
                        error = sooptcopyin(sopt, &extmac, sizeof(extmac),
                            sizeof(extmac));
                        if (error)
                                return (error);
                        error = mac_getsockopt_peerlabel(
                            sopt->sopt_td->td_ucred, so, &extmac);
                        if (error)
                                return (error);
                        error = sooptcopyout(sopt, &extmac, sizeof extmac);
#else
                        error = EOPNOTSUPP;
#endif
                        break;

                case SO_LISTENQLIMIT:
                        optval = so->so_qlimit;
                        goto integer;

                case SO_LISTENQLEN:
                        optval = so->so_qlen;
                        goto integer;

                case SO_LISTENINCQLEN:
                        optval = so->so_incqlen;
                        goto integer;

                default:
                        error = ENOPROTOOPT;
                        break;
                }
                return (error);
        }
}

/* XXX; prepare mbuf for (__FreeBSD__ < 3) routines. */
int
soopt_getm(struct sockopt *sopt, struct mbuf **mp)
{
        struct mbuf *m, *m_prev;
        int sopt_size = sopt->sopt_valsize;

        MGET(m, sopt->sopt_td ? M_TRYWAIT : M_DONTWAIT, MT_DATA);
        if (m == NULL)
                return ENOBUFS;
        if (sopt_size > MLEN) {
                MCLGET(m, sopt->sopt_td ? M_TRYWAIT : M_DONTWAIT);
                if ((m->m_flags & M_EXT) == 0) {
                        m_free(m);
                        return ENOBUFS;
                }
                m->m_len = min(MCLBYTES, sopt_size);
        } else {
                m->m_len = min(MLEN, sopt_size);
        }
        sopt_size -= m->m_len;
        *mp = m;
        m_prev = m;

        while (sopt_size) {
                MGET(m, sopt->sopt_td ? M_TRYWAIT : M_DONTWAIT, MT_DATA);
                if (m == NULL) {
                        m_freem(*mp);
                        return ENOBUFS;
                }
                if (sopt_size > MLEN) {
                        MCLGET(m, sopt->sopt_td != NULL ? M_TRYWAIT :
                            M_DONTWAIT);
                        if ((m->m_flags & M_EXT) == 0) {
                                m_freem(m);
                                m_freem(*mp);
                                return ENOBUFS;
                        }
                        m->m_len = min(MCLBYTES, sopt_size);
                } else {
                        m->m_len = min(MLEN, sopt_size);
                }
                sopt_size -= m->m_len;
                m_prev->m_next = m;
                m_prev = m;
        }
        return (0);
}

/* XXX; copyin sopt data into mbuf chain for (__FreeBSD__ < 3) routines. */
int
soopt_mcopyin(struct sockopt *sopt, struct mbuf *m)
{
        struct mbuf *m0 = m;

        if (sopt->sopt_val == NULL)
                return (0);
        while (m != NULL && sopt->sopt_valsize >= m->m_len) {
                if (sopt->sopt_td != NULL) {
                        int error;

                        error = copyin(sopt->sopt_val, mtod(m, char *),
                                       m->m_len);
                        if (error != 0) {
                                m_freem(m0);
                                return(error);
                        }
                } else
                        bcopy(sopt->sopt_val, mtod(m, char *), m->m_len);
                sopt->sopt_valsize -= m->m_len;
                sopt->sopt_val = (char *)sopt->sopt_val + m->m_len;
                m = m->m_next;
        }
        if (m != NULL) /* should be allocated enoughly at ip6_sooptmcopyin() */
                panic("ip6_sooptmcopyin");
        return (0);
}

/* XXX; copyout mbuf chain data into soopt for (__FreeBSD__ < 3) routines. */
int
soopt_mcopyout(struct sockopt *sopt, struct mbuf *m)
{
        struct mbuf *m0 = m;
        size_t valsize = 0;

        if (sopt->sopt_val == NULL)
                return (0);
        while (m != NULL && sopt->sopt_valsize >= m->m_len) {
                if (sopt->sopt_td != NULL) {
                        int error;

                        error = copyout(mtod(m, char *), sopt->sopt_val,
                                       m->m_len);
                        if (error != 0) {
                                m_freem(m0);
                                return(error);
                        }
                } else
                        bcopy(mtod(m, char *), sopt->sopt_val, m->m_len);
               sopt->sopt_valsize -= m->m_len;
               sopt->sopt_val = (char *)sopt->sopt_val + m->m_len;
               valsize += m->m_len;
               m = m->m_next;
        }
        if (m != NULL) {
                /* enough soopt buffer should be given from user-land */
                m_freem(m0);
                return(EINVAL);
        }
        sopt->sopt_valsize = valsize;
        return (0);
}

void
sohasoutofband(so)
        struct socket *so;
{
        if (so->so_sigio != NULL)
                pgsigio(&so->so_sigio, SIGURG, 0);
        selwakeuppri(&so->so_rcv.sb_sel, PSOCK);
}

int
sopoll(struct socket *so, int events, struct ucred *active_cred,
    struct thread *td)
{
        int revents = 0;

        SOCKBUF_LOCK(&so->so_snd);
        SOCKBUF_LOCK(&so->so_rcv);
        if (events & (POLLIN | POLLRDNORM))
                if (soreadable(so))
                        revents |= events & (POLLIN | POLLRDNORM);

        if (events & POLLINIGNEOF)
                if (so->so_rcv.sb_cc >= so->so_rcv.sb_lowat ||
                    !TAILQ_EMPTY(&so->so_comp) || so->so_error)
                        revents |= POLLINIGNEOF;

        if (events & (POLLOUT | POLLWRNORM))
                if (sowriteable(so))
                        revents |= events & (POLLOUT | POLLWRNORM);

        if (events & (POLLPRI | POLLRDBAND))
                if (so->so_oobmark || (so->so_rcv.sb_state & SBS_RCVATMARK))
                        revents |= events & (POLLPRI | POLLRDBAND);

        if (revents == 0) {
                if (events &
                    (POLLIN | POLLINIGNEOF | POLLPRI | POLLRDNORM |
                     POLLRDBAND)) {
                        selrecord(td, &so->so_rcv.sb_sel);
                        so->so_rcv.sb_flags |= SB_SEL;
                }

                if (events & (POLLOUT | POLLWRNORM)) {
                        selrecord(td, &so->so_snd.sb_sel);
                        so->so_snd.sb_flags |= SB_SEL;
                }
        }

        SOCKBUF_UNLOCK(&so->so_rcv);
        SOCKBUF_UNLOCK(&so->so_snd);
        return (revents);
}

int
soo_kqfilter(struct file *fp, struct knote *kn)
{
        struct socket *so = kn->kn_fp->f_data;
        struct sockbuf *sb;

        switch (kn->kn_filter) {
        case EVFILT_READ:
                if (so->so_options & SO_ACCEPTCONN)
                        kn->kn_fop = &solisten_filtops;
                else
                        kn->kn_fop = &soread_filtops;
                sb = &so->so_rcv;
                break;
        case EVFILT_WRITE:
                kn->kn_fop = &sowrite_filtops;
                sb = &so->so_snd;
                break;
        default:
                return (EINVAL);
        }

        SOCKBUF_LOCK(sb);
        knlist_add(&sb->sb_sel.si_note, kn, 1);
        sb->sb_flags |= SB_KNOTE;
        SOCKBUF_UNLOCK(sb);
        return (0);
}

static void
filt_sordetach(struct knote *kn)
{
        struct socket *so = kn->kn_fp->f_data;

        SOCKBUF_LOCK(&so->so_rcv);
        knlist_remove(&so->so_rcv.sb_sel.si_note, kn, 1);
        if (knlist_empty(&so->so_rcv.sb_sel.si_note))
                so->so_rcv.sb_flags &= ~SB_KNOTE;
        SOCKBUF_UNLOCK(&so->so_rcv);
}

/*ARGSUSED*/
static int
filt_soread(struct knote *kn, long hint)
{
        struct socket *so;

        so = kn->kn_fp->f_data;
        SOCKBUF_LOCK_ASSERT(&so->so_rcv);

        kn->kn_data = so->so_rcv.sb_cc - so->so_rcv.sb_ctl;
        if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
                kn->kn_flags |= EV_EOF;
                kn->kn_fflags = so->so_error;
                return (1);
        } else if (so->so_error)        /* temporary udp error */
                return (1);
        else if (kn->kn_sfflags & NOTE_LOWAT)
                return (kn->kn_data >= kn->kn_sdata);
        else
                return (so->so_rcv.sb_cc >= so->so_rcv.sb_lowat);
}

static void
filt_sowdetach(struct knote *kn)
{
        struct socket *so = kn->kn_fp->f_data;

        SOCKBUF_LOCK(&so->so_snd);
        knlist_remove(&so->so_snd.sb_sel.si_note, kn, 1);
        if (knlist_empty(&so->so_snd.sb_sel.si_note))
                so->so_snd.sb_flags &= ~SB_KNOTE;
        SOCKBUF_UNLOCK(&so->so_snd);
}

/*ARGSUSED*/
static int
filt_sowrite(struct knote *kn, long hint)
{
        struct socket *so;

        so = kn->kn_fp->f_data;
        SOCKBUF_LOCK_ASSERT(&so->so_snd);
        kn->kn_data = sbspace(&so->so_snd);
        if (so->so_snd.sb_state & SBS_CANTSENDMORE) {
                kn->kn_flags |= EV_EOF;
                kn->kn_fflags = so->so_error;
                return (1);
        } else if (so->so_error)        /* temporary udp error */
                return (1);
        else if (((so->so_state & SS_ISCONNECTED) == 0) &&
            (so->so_proto->pr_flags & PR_CONNREQUIRED))
                return (0);
        else if (kn->kn_sfflags & NOTE_LOWAT)
                return (kn->kn_data >= kn->kn_sdata);
        else
                return (kn->kn_data >= so->so_snd.sb_lowat);
}

/*ARGSUSED*/
static int
filt_solisten(struct knote *kn, long hint)
{
        struct socket *so = kn->kn_fp->f_data;

        kn->kn_data = so->so_qlen;
        return (! TAILQ_EMPTY(&so->so_comp));
}

int
socheckuid(struct socket *so, uid_t uid)
{

        if (so == NULL)
                return (EPERM);
        if (so->so_cred->cr_uid != uid)
                return (EPERM);
        return (0);
}

static int
somaxconn_sysctl(SYSCTL_HANDLER_ARGS)
{
        int error;
        int val;

        val = somaxconn;
        error = sysctl_handle_int(oidp, &val, sizeof(int), req);
        if (error || !req->newptr )
                return (error);

        if (val < 1 || val > USHRT_MAX)
                return (EINVAL);

        somaxconn = val;
        return (0);
}