import nvi 2.2.0-3bbdfe4

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

/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1989 Stephen Deering
 * Copyright (c) 1992, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Stephen Deering of Stanford University.
 *
 * 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.
 * 3. 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.
 *
 *      @(#)ip_mroute.c 8.2 (Berkeley) 11/15/93
 */

/*
 * IP multicast forwarding procedures
 *
 * Written by David Waitzman, BBN Labs, August 1988.
 * Modified by Steve Deering, Stanford, February 1989.
 * Modified by Mark J. Steiglitz, Stanford, May, 1991
 * Modified by Van Jacobson, LBL, January 1993
 * Modified by Ajit Thyagarajan, PARC, August 1993
 * Modified by Bill Fenner, PARC, April 1995
 * Modified by Ahmed Helmy, SGI, June 1996
 * Modified by George Edmond Eddy (Rusty), ISI, February 1998
 * Modified by Pavlin Radoslavov, USC/ISI, May 1998, August 1999, October 2000
 * Modified by Hitoshi Asaeda, WIDE, August 2000
 * Modified by Pavlin Radoslavov, ICSI, October 2002
 * Modified by Wojciech Macek, Semihalf, May 2021
 *
 * MROUTING Revision: 3.5
 * and PIM-SMv2 and PIM-DM support, advanced API support,
 * bandwidth metering and signaling
 */

/*
 * TODO: Prefix functions with ipmf_.
 * TODO: Maintain a refcount on if_allmulti() in ifnet or in the protocol
 * domain attachment (if_afdata) so we can track consumers of that service.
 * TODO: Deprecate routing socket path for SIOCGETSGCNT and SIOCGETVIFCNT,
 * move it to socket options.
 * TODO: Cleanup LSRR removal further.
 * TODO: Push RSVP stubs into raw_ip.c.
 * TODO: Use bitstring.h for vif set.
 * TODO: Fix mrt6_ioctl dangling ref when dynamically loaded.
 * TODO: Sync ip6_mroute.c with this file.
 */

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

#include "opt_inet.h"
#include "opt_mrouting.h"

#define _PIM_VT 1

#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/stddef.h>
#include <sys/eventhandler.h>
#include <sys/lock.h>
#include <sys/ktr.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/module.h>
#include <sys/priv.h>
#include <sys/protosw.h>
#include <sys/signalvar.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sockio.h>
#include <sys/sx.h>
#include <sys/sysctl.h>
#include <sys/syslog.h>
#include <sys/systm.h>
#include <sys/time.h>
#include <sys/counter.h>

#include <net/if.h>
#include <net/if_var.h>
#include <net/netisr.h>
#include <net/route.h>
#include <net/vnet.h>

#include <netinet/in.h>
#include <netinet/igmp.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#include <netinet/ip_encap.h>
#include <netinet/ip_mroute.h>
#include <netinet/ip_var.h>
#include <netinet/ip_options.h>
#include <netinet/pim.h>
#include <netinet/pim_var.h>
#include <netinet/udp.h>

#include <machine/in_cksum.h>

#ifndef KTR_IPMF
#define KTR_IPMF KTR_INET
#endif

#define         VIFI_INVALID    ((vifi_t) -1)

static MALLOC_DEFINE(M_MRTABLE, "mroutetbl", "multicast forwarding cache");

/*
 * Locking.  We use two locks: one for the virtual interface table and
 * one for the forwarding table.  These locks may be nested in which case
 * the VIF lock must always be taken first.  Note that each lock is used
 * to cover not only the specific data structure but also related data
 * structures.
 */

static struct mtx mrouter_mtx;
#define MROUTER_LOCK()          mtx_lock(&mrouter_mtx)
#define MROUTER_UNLOCK()        mtx_unlock(&mrouter_mtx)
#define MROUTER_LOCK_ASSERT()   mtx_assert(&mrouter_mtx, MA_OWNED)
#define MROUTER_LOCK_INIT()                                             \
        mtx_init(&mrouter_mtx, "IPv4 multicast forwarding", NULL, MTX_DEF)
#define MROUTER_LOCK_DESTROY()  mtx_destroy(&mrouter_mtx)

static int ip_mrouter_cnt;      /* # of vnets with active mrouters */
static int ip_mrouter_unloading; /* Allow no more V_ip_mrouter sockets */

VNET_PCPUSTAT_DEFINE_STATIC(struct mrtstat, mrtstat);
VNET_PCPUSTAT_SYSINIT(mrtstat);
VNET_PCPUSTAT_SYSUNINIT(mrtstat);
SYSCTL_VNET_PCPUSTAT(_net_inet_ip, OID_AUTO, mrtstat, struct mrtstat,
    mrtstat, "IPv4 Multicast Forwarding Statistics (struct mrtstat, "
    "netinet/ip_mroute.h)");

VNET_DEFINE_STATIC(u_long, mfchash);
#define V_mfchash               VNET(mfchash)
#define MFCHASH(a, g)                                                   \
        ((((a).s_addr >> 20) ^ ((a).s_addr >> 10) ^ (a).s_addr ^ \
          ((g).s_addr >> 20) ^ ((g).s_addr >> 10) ^ (g).s_addr) & V_mfchash)
#define MFCHASHSIZE     256

static u_long mfchashsize;                      /* Hash size */
VNET_DEFINE_STATIC(u_char *, nexpire);          /* 0..mfchashsize-1 */
#define V_nexpire               VNET(nexpire)
VNET_DEFINE_STATIC(LIST_HEAD(mfchashhdr, mfc)*, mfchashtbl);
#define V_mfchashtbl            VNET(mfchashtbl)

static struct mtx mfc_mtx;
#define MFC_LOCK()              mtx_lock(&mfc_mtx)
#define MFC_UNLOCK()            mtx_unlock(&mfc_mtx)
#define MFC_LOCK_ASSERT()       mtx_assert(&mfc_mtx, MA_OWNED)
#define MFC_LOCK_INIT()                                                 \
        mtx_init(&mfc_mtx, "IPv4 multicast forwarding cache", NULL, MTX_DEF)
#define MFC_LOCK_DESTROY()      mtx_destroy(&mfc_mtx)

VNET_DEFINE_STATIC(vifi_t, numvifs);
#define V_numvifs               VNET(numvifs)
VNET_DEFINE_STATIC(struct vif *, viftable);
#define V_viftable              VNET(viftable)

static struct mtx vif_mtx;
#define VIF_LOCK()              mtx_lock(&vif_mtx)
#define VIF_UNLOCK()            mtx_unlock(&vif_mtx)
#define VIF_LOCK_ASSERT()       mtx_assert(&vif_mtx, MA_OWNED)
#define VIF_LOCK_INIT()                                                 \
        mtx_init(&vif_mtx, "IPv4 multicast interfaces", NULL, MTX_DEF)
#define VIF_LOCK_DESTROY()      mtx_destroy(&vif_mtx)

static eventhandler_tag if_detach_event_tag = NULL;

VNET_DEFINE_STATIC(struct callout, expire_upcalls_ch);
#define V_expire_upcalls_ch     VNET(expire_upcalls_ch)

#define         EXPIRE_TIMEOUT  (hz / 4)        /* 4x / second          */
#define         UPCALL_EXPIRE   6               /* number of timeouts   */

/*
 * Bandwidth meter variables and constants
 */
static MALLOC_DEFINE(M_BWMETER, "bwmeter", "multicast upcall bw meters");

/*
 * Pending upcalls are stored in a vector which is flushed when
 * full, or periodically
 */
VNET_DEFINE_STATIC(struct bw_upcall *, bw_upcalls);
#define V_bw_upcalls            VNET(bw_upcalls)
VNET_DEFINE_STATIC(u_int, bw_upcalls_n); /* # of pending upcalls */
#define V_bw_upcalls_n          VNET(bw_upcalls_n)
VNET_DEFINE_STATIC(struct callout, bw_upcalls_ch);
#define V_bw_upcalls_ch         VNET(bw_upcalls_ch)

#define BW_UPCALLS_PERIOD (hz)          /* periodical flush of bw upcalls */

VNET_PCPUSTAT_DEFINE_STATIC(struct pimstat, pimstat);
VNET_PCPUSTAT_SYSINIT(pimstat);
VNET_PCPUSTAT_SYSUNINIT(pimstat);

SYSCTL_NODE(_net_inet, IPPROTO_PIM, pim, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
    "PIM");
SYSCTL_VNET_PCPUSTAT(_net_inet_pim, PIMCTL_STATS, stats, struct pimstat,
    pimstat, "PIM Statistics (struct pimstat, netinet/pim_var.h)");

static u_long   pim_squelch_wholepkt = 0;
SYSCTL_ULONG(_net_inet_pim, OID_AUTO, squelch_wholepkt, CTLFLAG_RW,
    &pim_squelch_wholepkt, 0,
    "Disable IGMP_WHOLEPKT notifications if rendezvous point is unspecified");

static const struct encaptab *pim_encap_cookie;
static int pim_encapcheck(const struct mbuf *, int, int, void *);
static int pim_input(struct mbuf *, int, int, void *);

extern int in_mcast_loop;

static const struct encap_config ipv4_encap_cfg = {
        .proto = IPPROTO_PIM,
        .min_length = sizeof(struct ip) + PIM_MINLEN,
        .exact_match = 8,
        .check = pim_encapcheck,
        .input = pim_input
};

/*
 * Note: the PIM Register encapsulation adds the following in front of a
 * data packet:
 *
 * struct pim_encap_hdr {
 *    struct ip ip;
 *    struct pim_encap_pimhdr  pim;
 * }
 *
 */

struct pim_encap_pimhdr {
        struct pim pim;
        uint32_t   flags;
};
#define         PIM_ENCAP_TTL   64

static struct ip pim_encap_iphdr = {
#if BYTE_ORDER == LITTLE_ENDIAN
        sizeof(struct ip) >> 2,
        IPVERSION,
#else
        IPVERSION,
        sizeof(struct ip) >> 2,
#endif
        0,                      /* tos */
        sizeof(struct ip),      /* total length */
        0,                      /* id */
        0,                      /* frag offset */
        PIM_ENCAP_TTL,
        IPPROTO_PIM,
        0,                      /* checksum */
};

static struct pim_encap_pimhdr pim_encap_pimhdr = {
    {
        PIM_MAKE_VT(PIM_VERSION, PIM_REGISTER), /* PIM vers and message type */
        0,                      /* reserved */
        0,                      /* checksum */
    },
    0                           /* flags */
};

VNET_DEFINE_STATIC(vifi_t, reg_vif_num) = VIFI_INVALID;
#define V_reg_vif_num           VNET(reg_vif_num)
VNET_DEFINE_STATIC(struct ifnet, multicast_register_if);
#define V_multicast_register_if VNET(multicast_register_if)

/*
 * Private variables.
 */

static u_long   X_ip_mcast_src(int);
static int      X_ip_mforward(struct ip *, struct ifnet *, struct mbuf *,
                    struct ip_moptions *);
static int      X_ip_mrouter_done(void);
static int      X_ip_mrouter_get(struct socket *, struct sockopt *);
static int      X_ip_mrouter_set(struct socket *, struct sockopt *);
static int      X_legal_vif_num(int);
static int      X_mrt_ioctl(u_long, caddr_t, int);

static int      add_bw_upcall(struct bw_upcall *);
static int      add_mfc(struct mfcctl2 *);
static int      add_vif(struct vifctl *);
static void     bw_meter_prepare_upcall(struct bw_meter *, struct timeval *);
static void     bw_meter_geq_receive_packet(struct bw_meter *, int,
                    struct timeval *);
static void     bw_upcalls_send(void);
static int      del_bw_upcall(struct bw_upcall *);
static int      del_mfc(struct mfcctl2 *);
static int      del_vif(vifi_t);
static int      del_vif_locked(vifi_t);
static void     expire_bw_upcalls_send(void *);
static void     expire_mfc(struct mfc *);
static void     expire_upcalls(void *);
static void     free_bw_list(struct bw_meter *);
static int      get_sg_cnt(struct sioc_sg_req *);
static int      get_vif_cnt(struct sioc_vif_req *);
static void     if_detached_event(void *, struct ifnet *);
static int      ip_mdq(struct mbuf *, struct ifnet *, struct mfc *, vifi_t);
static int      ip_mrouter_init(struct socket *, int);
static __inline struct mfc *
                mfc_find(struct in_addr *, struct in_addr *);
static void     phyint_send(struct ip *, struct vif *, struct mbuf *);
static struct mbuf *
                pim_register_prepare(struct ip *, struct mbuf *);
static int      pim_register_send(struct ip *, struct vif *,
                    struct mbuf *, struct mfc *);
static int      pim_register_send_rp(struct ip *, struct vif *,
                    struct mbuf *, struct mfc *);
static int      pim_register_send_upcall(struct ip *, struct vif *,
                    struct mbuf *, struct mfc *);
static void     send_packet(struct vif *, struct mbuf *);
static int      set_api_config(uint32_t *);
static int      set_assert(int);
static int      socket_send(struct socket *, struct mbuf *,
                    struct sockaddr_in *);

/*
 * Kernel multicast forwarding API capabilities and setup.
 * If more API capabilities are added to the kernel, they should be
 * recorded in `mrt_api_support'.
 */
#define MRT_API_VERSION         0x0305

static const int mrt_api_version = MRT_API_VERSION;
static const uint32_t mrt_api_support = (MRT_MFC_FLAGS_DISABLE_WRONGVIF |
                                         MRT_MFC_FLAGS_BORDER_VIF |
                                         MRT_MFC_RP |
                                         MRT_MFC_BW_UPCALL);
VNET_DEFINE_STATIC(uint32_t, mrt_api_config);
#define V_mrt_api_config        VNET(mrt_api_config)
VNET_DEFINE_STATIC(int, pim_assert_enabled);
#define V_pim_assert_enabled    VNET(pim_assert_enabled)
static struct timeval pim_assert_interval = { 3, 0 };   /* Rate limit */

/*
 * Find a route for a given origin IP address and multicast group address.
 * Statistics must be updated by the caller.
 */
static __inline struct mfc *
mfc_find(struct in_addr *o, struct in_addr *g)
{
        struct mfc *rt;

        MFC_LOCK_ASSERT();

        LIST_FOREACH(rt, &V_mfchashtbl[MFCHASH(*o, *g)], mfc_hash) {
                if (in_hosteq(rt->mfc_origin, *o) &&
                    in_hosteq(rt->mfc_mcastgrp, *g) &&
                    TAILQ_EMPTY(&rt->mfc_stall))
                        break;
        }

        return (rt);
}

/*
 * Handle MRT setsockopt commands to modify the multicast forwarding tables.
 */
static int
X_ip_mrouter_set(struct socket *so, struct sockopt *sopt)
{
    int error, optval;
    vifi_t      vifi;
    struct      vifctl vifc;
    struct      mfcctl2 mfc;
    struct      bw_upcall bw_upcall;
    uint32_t    i;

    if (so != V_ip_mrouter && sopt->sopt_name != MRT_INIT)
        return EPERM;

    error = 0;
    switch (sopt->sopt_name) {
    case MRT_INIT:
        error = sooptcopyin(sopt, &optval, sizeof optval, sizeof optval);
        if (error)
            break;
        error = ip_mrouter_init(so, optval);
        break;

    case MRT_DONE:
        error = ip_mrouter_done();
        break;

    case MRT_ADD_VIF:
        error = sooptcopyin(sopt, &vifc, sizeof vifc, sizeof vifc);
        if (error)
            break;
        error = add_vif(&vifc);
        break;

    case MRT_DEL_VIF:
        error = sooptcopyin(sopt, &vifi, sizeof vifi, sizeof vifi);
        if (error)
            break;
        error = del_vif(vifi);
        break;

    case MRT_ADD_MFC:
    case MRT_DEL_MFC:
        /*
         * select data size depending on API version.
         */
        if (sopt->sopt_name == MRT_ADD_MFC &&
                V_mrt_api_config & MRT_API_FLAGS_ALL) {
            error = sooptcopyin(sopt, &mfc, sizeof(struct mfcctl2),
                                sizeof(struct mfcctl2));
        } else {
            error = sooptcopyin(sopt, &mfc, sizeof(struct mfcctl),
                                sizeof(struct mfcctl));
            bzero((caddr_t)&mfc + sizeof(struct mfcctl),
                        sizeof(mfc) - sizeof(struct mfcctl));
        }
        if (error)
            break;
        if (sopt->sopt_name == MRT_ADD_MFC)
            error = add_mfc(&mfc);
        else
            error = del_mfc(&mfc);
        break;

    case MRT_ASSERT:
        error = sooptcopyin(sopt, &optval, sizeof optval, sizeof optval);
        if (error)
            break;
        set_assert(optval);
        break;

    case MRT_API_CONFIG:
        error = sooptcopyin(sopt, &i, sizeof i, sizeof i);
        if (!error)
            error = set_api_config(&i);
        if (!error)
            error = sooptcopyout(sopt, &i, sizeof i);
        break;

    case MRT_ADD_BW_UPCALL:
    case MRT_DEL_BW_UPCALL:
        error = sooptcopyin(sopt, &bw_upcall, sizeof bw_upcall,
                                sizeof bw_upcall);
        if (error)
            break;
        if (sopt->sopt_name == MRT_ADD_BW_UPCALL)
            error = add_bw_upcall(&bw_upcall);
        else
            error = del_bw_upcall(&bw_upcall);
        break;

    default:
        error = EOPNOTSUPP;
        break;
    }
    return error;
}

/*
 * Handle MRT getsockopt commands
 */
static int
X_ip_mrouter_get(struct socket *so, struct sockopt *sopt)
{
    int error;

    switch (sopt->sopt_name) {
    case MRT_VERSION:
        error = sooptcopyout(sopt, &mrt_api_version, sizeof mrt_api_version);
        break;

    case MRT_ASSERT:
        error = sooptcopyout(sopt, &V_pim_assert_enabled,
            sizeof V_pim_assert_enabled);
        break;

    case MRT_API_SUPPORT:
        error = sooptcopyout(sopt, &mrt_api_support, sizeof mrt_api_support);
        break;

    case MRT_API_CONFIG:
        error = sooptcopyout(sopt, &V_mrt_api_config, sizeof V_mrt_api_config);
        break;

    default:
        error = EOPNOTSUPP;
        break;
    }
    return error;
}

/*
 * Handle ioctl commands to obtain information from the cache
 */
static int
X_mrt_ioctl(u_long cmd, caddr_t data, int fibnum __unused)
{
    int error = 0;

    /*
     * Currently the only function calling this ioctl routine is rtioctl_fib().
     * Typically, only root can create the raw socket in order to execute
     * this ioctl method, however the request might be coming from a prison
     */
    error = priv_check(curthread, PRIV_NETINET_MROUTE);
    if (error)
        return (error);
    switch (cmd) {
    case (SIOCGETVIFCNT):
        error = get_vif_cnt((struct sioc_vif_req *)data);
        break;

    case (SIOCGETSGCNT):
        error = get_sg_cnt((struct sioc_sg_req *)data);
        break;

    default:
        error = EINVAL;
        break;
    }
    return error;
}

/*
 * returns the packet, byte, rpf-failure count for the source group provided
 */
static int
get_sg_cnt(struct sioc_sg_req *req)
{
    struct mfc *rt;

    MFC_LOCK();
    rt = mfc_find(&req->src, &req->grp);
    if (rt == NULL) {
        MFC_UNLOCK();
        req->pktcnt = req->bytecnt = req->wrong_if = 0xffffffff;
        return EADDRNOTAVAIL;
    }
    req->pktcnt = rt->mfc_pkt_cnt;
    req->bytecnt = rt->mfc_byte_cnt;
    req->wrong_if = rt->mfc_wrong_if;
    MFC_UNLOCK();
    return 0;
}

/*
 * returns the input and output packet and byte counts on the vif provided
 */
static int
get_vif_cnt(struct sioc_vif_req *req)
{
    vifi_t vifi = req->vifi;

    VIF_LOCK();
    if (vifi >= V_numvifs) {
        VIF_UNLOCK();
        return EINVAL;
    }

    req->icount = V_viftable[vifi].v_pkt_in;
    req->ocount = V_viftable[vifi].v_pkt_out;
    req->ibytes = V_viftable[vifi].v_bytes_in;
    req->obytes = V_viftable[vifi].v_bytes_out;
    VIF_UNLOCK();

    return 0;
}

static void
if_detached_event(void *arg __unused, struct ifnet *ifp)
{
    vifi_t vifi;
    u_long i;

    MROUTER_LOCK();

    if (V_ip_mrouter == NULL) {
        MROUTER_UNLOCK();
        return;
    }

    VIF_LOCK();
    MFC_LOCK();

    /*
     * Tear down multicast forwarder state associated with this ifnet.
     * 1. Walk the vif list, matching vifs against this ifnet.
     * 2. Walk the multicast forwarding cache (mfc) looking for
     *    inner matches with this vif's index.
     * 3. Expire any matching multicast forwarding cache entries.
     * 4. Free vif state. This should disable ALLMULTI on the interface.
     */
    for (vifi = 0; vifi < V_numvifs; vifi++) {
        if (V_viftable[vifi].v_ifp != ifp)
                continue;
        for (i = 0; i < mfchashsize; i++) {
                struct mfc *rt, *nrt;

                LIST_FOREACH_SAFE(rt, &V_mfchashtbl[i], mfc_hash, nrt) {
                        if (rt->mfc_parent == vifi) {
                                expire_mfc(rt);
                        }
                }
        }
        del_vif_locked(vifi);
    }

    MFC_UNLOCK();
    VIF_UNLOCK();

    MROUTER_UNLOCK();
}

/*
 * Enable multicast forwarding.
 */
static int
ip_mrouter_init(struct socket *so, int version)
{

    CTR3(KTR_IPMF, "%s: so_type %d, pr_protocol %d", __func__,
        so->so_type, so->so_proto->pr_protocol);

    if (so->so_type != SOCK_RAW || so->so_proto->pr_protocol != IPPROTO_IGMP)
        return EOPNOTSUPP;

    if (version != 1)
        return ENOPROTOOPT;

    MROUTER_LOCK();

    if (ip_mrouter_unloading) {
        MROUTER_UNLOCK();
        return ENOPROTOOPT;
    }

    if (V_ip_mrouter != NULL) {
        MROUTER_UNLOCK();
        return EADDRINUSE;
    }

    V_mfchashtbl = hashinit_flags(mfchashsize, M_MRTABLE, &V_mfchash,
        HASH_NOWAIT);

    callout_reset(&V_expire_upcalls_ch, EXPIRE_TIMEOUT, expire_upcalls,
        curvnet);
    callout_reset(&V_bw_upcalls_ch, BW_UPCALLS_PERIOD, expire_bw_upcalls_send,
        curvnet);

    V_ip_mrouter = so;
    ip_mrouter_cnt++;

    MROUTER_UNLOCK();

    CTR1(KTR_IPMF, "%s: done", __func__);

    return 0;
}

/*
 * Disable multicast forwarding.
 */
static int
X_ip_mrouter_done(void)
{
    struct ifnet *ifp;
    u_long i;
    vifi_t vifi;

    MROUTER_LOCK();

    if (V_ip_mrouter == NULL) {
        MROUTER_UNLOCK();
        return EINVAL;
    }

    /*
     * Detach/disable hooks to the reset of the system.
     */
    V_ip_mrouter = NULL;
    ip_mrouter_cnt--;
    V_mrt_api_config = 0;

    MROUTER_WAIT();

    VIF_LOCK();

    /*
     * For each phyint in use, disable promiscuous reception of all IP
     * multicasts.
     */
    for (vifi = 0; vifi < V_numvifs; vifi++) {
        if (!in_nullhost(V_viftable[vifi].v_lcl_addr) &&
                !(V_viftable[vifi].v_flags & (VIFF_TUNNEL | VIFF_REGISTER))) {
            ifp = V_viftable[vifi].v_ifp;
            if_allmulti(ifp, 0);
        }
    }
    bzero((caddr_t)V_viftable, sizeof(*V_viftable) * MAXVIFS);
    V_numvifs = 0;
    V_pim_assert_enabled = 0;

    VIF_UNLOCK();

    callout_stop(&V_expire_upcalls_ch);
    callout_stop(&V_bw_upcalls_ch);

    MFC_LOCK();

    /*
     * Free all multicast forwarding cache entries.
     * Do not use hashdestroy(), as we must perform other cleanup.
     */
    for (i = 0; i < mfchashsize; i++) {
        struct mfc *rt, *nrt;

        LIST_FOREACH_SAFE(rt, &V_mfchashtbl[i], mfc_hash, nrt) {
                expire_mfc(rt);
        }
    }
    free(V_mfchashtbl, M_MRTABLE);
    V_mfchashtbl = NULL;

    bzero(V_nexpire, sizeof(V_nexpire[0]) * mfchashsize);

    V_bw_upcalls_n = 0;

    MFC_UNLOCK();

    V_reg_vif_num = VIFI_INVALID;

    MROUTER_UNLOCK();

    CTR1(KTR_IPMF, "%s: done", __func__);

    return 0;
}

/*
 * Set PIM assert processing global
 */
static int
set_assert(int i)
{
    if ((i != 1) && (i != 0))
        return EINVAL;

    V_pim_assert_enabled = i;

    return 0;
}

/*
 * Configure API capabilities
 */
int
set_api_config(uint32_t *apival)
{
    u_long i;

    /*
     * We can set the API capabilities only if it is the first operation
     * after MRT_INIT. I.e.:
     *  - there are no vifs installed
     *  - pim_assert is not enabled
     *  - the MFC table is empty
     */
    if (V_numvifs > 0) {
        *apival = 0;
        return EPERM;
    }
    if (V_pim_assert_enabled) {
        *apival = 0;
        return EPERM;
    }

    MFC_LOCK();

    for (i = 0; i < mfchashsize; i++) {
        if (LIST_FIRST(&V_mfchashtbl[i]) != NULL) {
            MFC_UNLOCK();
            *apival = 0;
            return EPERM;
        }
    }

    MFC_UNLOCK();

    V_mrt_api_config = *apival & mrt_api_support;
    *apival = V_mrt_api_config;

    return 0;
}

/*
 * Add a vif to the vif table
 */
static int
add_vif(struct vifctl *vifcp)
{
    struct vif *vifp = V_viftable + vifcp->vifc_vifi;
    struct sockaddr_in sin = {sizeof sin, AF_INET};
    struct ifaddr *ifa;
    struct ifnet *ifp;
    int error;

    VIF_LOCK();
    if (vifcp->vifc_vifi >= MAXVIFS) {
        VIF_UNLOCK();
        return EINVAL;
    }
    /* rate limiting is no longer supported by this code */
    if (vifcp->vifc_rate_limit != 0) {
        log(LOG_ERR, "rate limiting is no longer supported\n");
        VIF_UNLOCK();
        return EINVAL;
    }
    if (!in_nullhost(vifp->v_lcl_addr)) {
        VIF_UNLOCK();
        return EADDRINUSE;
    }
    if (in_nullhost(vifcp->vifc_lcl_addr)) {
        VIF_UNLOCK();
        return EADDRNOTAVAIL;
    }

    /* Find the interface with an address in AF_INET family */
    if (vifcp->vifc_flags & VIFF_REGISTER) {
        /*
         * XXX: Because VIFF_REGISTER does not really need a valid
         * local interface (e.g. it could be 127.0.0.2), we don't
         * check its address.
         */
        ifp = NULL;
    } else {
        struct epoch_tracker et;

        sin.sin_addr = vifcp->vifc_lcl_addr;
        NET_EPOCH_ENTER(et);
        ifa = ifa_ifwithaddr((struct sockaddr *)&sin);
        if (ifa == NULL) {
            NET_EPOCH_EXIT(et);
            VIF_UNLOCK();
            return EADDRNOTAVAIL;
        }
        ifp = ifa->ifa_ifp;
        /* XXX FIXME we need to take a ref on ifp and cleanup properly! */
        NET_EPOCH_EXIT(et);
    }

    if ((vifcp->vifc_flags & VIFF_TUNNEL) != 0) {
        CTR1(KTR_IPMF, "%s: tunnels are no longer supported", __func__);
        VIF_UNLOCK();
        return EOPNOTSUPP;
    } else if (vifcp->vifc_flags & VIFF_REGISTER) {
        ifp = &V_multicast_register_if;
        CTR2(KTR_IPMF, "%s: add register vif for ifp %p", __func__, ifp);
        if (V_reg_vif_num == VIFI_INVALID) {
            if_initname(&V_multicast_register_if, "register_vif", 0);
            V_multicast_register_if.if_flags = IFF_LOOPBACK;
            V_reg_vif_num = vifcp->vifc_vifi;
        }
    } else {            /* Make sure the interface supports multicast */
        if ((ifp->if_flags & IFF_MULTICAST) == 0) {
            VIF_UNLOCK();
            return EOPNOTSUPP;
        }

        /* Enable promiscuous reception of all IP multicasts from the if */
        error = if_allmulti(ifp, 1);
        if (error) {
            VIF_UNLOCK();
            return error;
        }
    }

    vifp->v_flags     = vifcp->vifc_flags;
    vifp->v_threshold = vifcp->vifc_threshold;
    vifp->v_lcl_addr  = vifcp->vifc_lcl_addr;
    vifp->v_rmt_addr  = vifcp->vifc_rmt_addr;
    vifp->v_ifp       = ifp;
    /* initialize per vif pkt counters */
    vifp->v_pkt_in    = 0;
    vifp->v_pkt_out   = 0;
    vifp->v_bytes_in  = 0;
    vifp->v_bytes_out = 0;

    /* Adjust numvifs up if the vifi is higher than numvifs */
    if (V_numvifs <= vifcp->vifc_vifi)
        V_numvifs = vifcp->vifc_vifi + 1;

    VIF_UNLOCK();

    CTR4(KTR_IPMF, "%s: add vif %d laddr 0x%08x thresh %x", __func__,
        (int)vifcp->vifc_vifi, ntohl(vifcp->vifc_lcl_addr.s_addr),
        (int)vifcp->vifc_threshold);

    return 0;
}

/*
 * Delete a vif from the vif table
 */
static int
del_vif_locked(vifi_t vifi)
{
    struct vif *vifp;

    VIF_LOCK_ASSERT();

    if (vifi >= V_numvifs) {
        return EINVAL;
    }
    vifp = &V_viftable[vifi];
    if (in_nullhost(vifp->v_lcl_addr)) {
        return EADDRNOTAVAIL;
    }

    if (!(vifp->v_flags & (VIFF_TUNNEL | VIFF_REGISTER)))
        if_allmulti(vifp->v_ifp, 0);

    if (vifp->v_flags & VIFF_REGISTER)
        V_reg_vif_num = VIFI_INVALID;

    bzero((caddr_t)vifp, sizeof (*vifp));

    CTR2(KTR_IPMF, "%s: delete vif %d", __func__, (int)vifi);

    /* Adjust numvifs down */
    for (vifi = V_numvifs; vifi > 0; vifi--)
        if (!in_nullhost(V_viftable[vifi-1].v_lcl_addr))
            break;
    V_numvifs = vifi;

    return 0;
}

static int
del_vif(vifi_t vifi)
{
    int cc;

    VIF_LOCK();
    cc = del_vif_locked(vifi);
    VIF_UNLOCK();

    return cc;
}

/*
 * update an mfc entry without resetting counters and S,G addresses.
 */
static void
update_mfc_params(struct mfc *rt, struct mfcctl2 *mfccp)
{
    int i;

    rt->mfc_parent = mfccp->mfcc_parent;
    for (i = 0; i < V_numvifs; i++) {
        rt->mfc_ttls[i] = mfccp->mfcc_ttls[i];
        rt->mfc_flags[i] = mfccp->mfcc_flags[i] & V_mrt_api_config &
            MRT_MFC_FLAGS_ALL;
    }
    /* set the RP address */
    if (V_mrt_api_config & MRT_MFC_RP)
        rt->mfc_rp = mfccp->mfcc_rp;
    else
        rt->mfc_rp.s_addr = INADDR_ANY;
}

/*
 * fully initialize an mfc entry from the parameter.
 */
static void
init_mfc_params(struct mfc *rt, struct mfcctl2 *mfccp)
{
    rt->mfc_origin     = mfccp->mfcc_origin;
    rt->mfc_mcastgrp   = mfccp->mfcc_mcastgrp;

    update_mfc_params(rt, mfccp);

    /* initialize pkt counters per src-grp */
    rt->mfc_pkt_cnt    = 0;
    rt->mfc_byte_cnt   = 0;
    rt->mfc_wrong_if   = 0;
    timevalclear(&rt->mfc_last_assert);
}

static void
expire_mfc(struct mfc *rt)
{
        struct rtdetq *rte, *nrte;

        MFC_LOCK_ASSERT();

        free_bw_list(rt->mfc_bw_meter_leq);
        free_bw_list(rt->mfc_bw_meter_geq);

        TAILQ_FOREACH_SAFE(rte, &rt->mfc_stall, rte_link, nrte) {
                m_freem(rte->m);
                TAILQ_REMOVE(&rt->mfc_stall, rte, rte_link);
                free(rte, M_MRTABLE);
        }

        LIST_REMOVE(rt, mfc_hash);
        free(rt, M_MRTABLE);
}

/*
 * Add an mfc entry
 */
static int
add_mfc(struct mfcctl2 *mfccp)
{
    struct mfc *rt;
    struct rtdetq *rte, *nrte;
    u_long hash = 0;
    u_short nstl;

    VIF_LOCK();
    MFC_LOCK();

    rt = mfc_find(&mfccp->mfcc_origin, &mfccp->mfcc_mcastgrp);

    /* If an entry already exists, just update the fields */
    if (rt) {
        CTR4(KTR_IPMF, "%s: update mfc orig 0x%08x group %lx parent %x",
            __func__, ntohl(mfccp->mfcc_origin.s_addr),
            (u_long)ntohl(mfccp->mfcc_mcastgrp.s_addr),
            mfccp->mfcc_parent);
        update_mfc_params(rt, mfccp);
        MFC_UNLOCK();
        VIF_UNLOCK();
        return (0);
    }

    /*
     * Find the entry for which the upcall was made and update
     */
    nstl = 0;
    hash = MFCHASH(mfccp->mfcc_origin, mfccp->mfcc_mcastgrp);
    LIST_FOREACH(rt, &V_mfchashtbl[hash], mfc_hash) {
        if (in_hosteq(rt->mfc_origin, mfccp->mfcc_origin) &&
            in_hosteq(rt->mfc_mcastgrp, mfccp->mfcc_mcastgrp) &&
            !TAILQ_EMPTY(&rt->mfc_stall)) {
                CTR5(KTR_IPMF,
                    "%s: add mfc orig 0x%08x group %lx parent %x qh %p",
                    __func__, ntohl(mfccp->mfcc_origin.s_addr),
                    (u_long)ntohl(mfccp->mfcc_mcastgrp.s_addr),
                    mfccp->mfcc_parent,
                    TAILQ_FIRST(&rt->mfc_stall));
                if (nstl++)
                        CTR1(KTR_IPMF, "%s: multiple matches", __func__);

                init_mfc_params(rt, mfccp);
                rt->mfc_expire = 0;     /* Don't clean this guy up */
                V_nexpire[hash]--;

                /* Free queued packets, but attempt to forward them first. */
                TAILQ_FOREACH_SAFE(rte, &rt->mfc_stall, rte_link, nrte) {
                        if (rte->ifp != NULL)
                                ip_mdq(rte->m, rte->ifp, rt, -1);
                        m_freem(rte->m);
                        TAILQ_REMOVE(&rt->mfc_stall, rte, rte_link);
                        rt->mfc_nstall--;
                        free(rte, M_MRTABLE);
                }
        }
    }

    /*
     * It is possible that an entry is being inserted without an upcall
     */
    if (nstl == 0) {
        CTR1(KTR_IPMF, "%s: adding mfc w/o upcall", __func__);
        LIST_FOREACH(rt, &V_mfchashtbl[hash], mfc_hash) {
                if (in_hosteq(rt->mfc_origin, mfccp->mfcc_origin) &&
                    in_hosteq(rt->mfc_mcastgrp, mfccp->mfcc_mcastgrp)) {
                        init_mfc_params(rt, mfccp);
                        if (rt->mfc_expire)
                            V_nexpire[hash]--;
                        rt->mfc_expire = 0;
                        break; /* XXX */
                }
        }

        if (rt == NULL) {               /* no upcall, so make a new entry */
            rt = (struct mfc *)malloc(sizeof(*rt), M_MRTABLE, M_NOWAIT);
            if (rt == NULL) {
                MFC_UNLOCK();
                VIF_UNLOCK();
                return (ENOBUFS);
            }

            init_mfc_params(rt, mfccp);
            TAILQ_INIT(&rt->mfc_stall);
            rt->mfc_nstall = 0;

            rt->mfc_expire     = 0;
            rt->mfc_bw_meter_leq = NULL;
            rt->mfc_bw_meter_geq = NULL;

            /* insert new entry at head of hash chain */
            LIST_INSERT_HEAD(&V_mfchashtbl[hash], rt, mfc_hash);
        }
    }

    MFC_UNLOCK();
    VIF_UNLOCK();

    return (0);
}

/*
 * Delete an mfc entry
 */
static int
del_mfc(struct mfcctl2 *mfccp)
{
    struct in_addr      origin;
    struct in_addr      mcastgrp;
    struct mfc          *rt;

    origin = mfccp->mfcc_origin;
    mcastgrp = mfccp->mfcc_mcastgrp;

    CTR3(KTR_IPMF, "%s: delete mfc orig 0x%08x group %lx", __func__,
        ntohl(origin.s_addr), (u_long)ntohl(mcastgrp.s_addr));

    MFC_LOCK();

    rt = mfc_find(&origin, &mcastgrp);
    if (rt == NULL) {
        MFC_UNLOCK();
        return EADDRNOTAVAIL;
    }

    /*
     * free the bw_meter entries
     */
    free_bw_list(rt->mfc_bw_meter_leq);
    rt->mfc_bw_meter_leq = NULL;
    free_bw_list(rt->mfc_bw_meter_geq);
    rt->mfc_bw_meter_geq = NULL;

    LIST_REMOVE(rt, mfc_hash);
    free(rt, M_MRTABLE);

    MFC_UNLOCK();

    return (0);
}

/*
 * Send a message to the routing daemon on the multicast routing socket.
 */
static int
socket_send(struct socket *s, struct mbuf *mm, struct sockaddr_in *src)
{
    if (s) {
        SOCKBUF_LOCK(&s->so_rcv);
        if (sbappendaddr_locked(&s->so_rcv, (struct sockaddr *)src, mm,
            NULL) != 0) {
            sorwakeup_locked(s);
            return 0;
        }
        SOCKBUF_UNLOCK(&s->so_rcv);
    }
    m_freem(mm);
    return -1;
}

/*
 * IP multicast forwarding function. This function assumes that the packet
 * pointed to by "ip" has arrived on (or is about to be sent to) the interface
 * pointed to by "ifp", and the packet is to be relayed to other networks
 * that have members of the packet's destination IP multicast group.
 *
 * The packet is returned unscathed to the caller, unless it is
 * erroneous, in which case a non-zero return value tells the caller to
 * discard it.
 */

#define TUNNEL_LEN  12  /* # bytes of IP option for tunnel encapsulation  */

static int
X_ip_mforward(struct ip *ip, struct ifnet *ifp, struct mbuf *m,
    struct ip_moptions *imo)
{
    struct mfc *rt;
    int error;
    vifi_t vifi;

    CTR3(KTR_IPMF, "ip_mforward: delete mfc orig 0x%08x group %lx ifp %p",
        ntohl(ip->ip_src.s_addr), (u_long)ntohl(ip->ip_dst.s_addr), ifp);

    if (ip->ip_hl < (sizeof(struct ip) + TUNNEL_LEN) >> 2 ||
                ((u_char *)(ip + 1))[1] != IPOPT_LSRR ) {
        /*
         * Packet arrived via a physical interface or
         * an encapsulated tunnel or a register_vif.
         */
    } else {
        /*
         * Packet arrived through a source-route tunnel.
         * Source-route tunnels are no longer supported.
         */
        return (1);
    }

    VIF_LOCK();
    MFC_LOCK();
    if (imo && ((vifi = imo->imo_multicast_vif) < V_numvifs)) {
        if (ip->ip_ttl < MAXTTL)
            ip->ip_ttl++;       /* compensate for -1 in *_send routines */
        error = ip_mdq(m, ifp, NULL, vifi);
        MFC_UNLOCK();
        VIF_UNLOCK();
        return error;
    }

    /*
     * Don't forward a packet with time-to-live of zero or one,
     * or a packet destined to a local-only group.
     */
    if (ip->ip_ttl <= 1 || IN_LOCAL_GROUP(ntohl(ip->ip_dst.s_addr))) {
        MFC_UNLOCK();
        VIF_UNLOCK();
        return 0;
    }

    /*
     * Determine forwarding vifs from the forwarding cache table
     */
    MRTSTAT_INC(mrts_mfc_lookups);
    rt = mfc_find(&ip->ip_src, &ip->ip_dst);

    /* Entry exists, so forward if necessary */
    if (rt != NULL) {
        error = ip_mdq(m, ifp, rt, -1);
        MFC_UNLOCK();
        VIF_UNLOCK();
        return error;
    } else {
        /*
         * If we don't have a route for packet's origin,
         * Make a copy of the packet & send message to routing daemon
         */

        struct mbuf *mb0;
        struct rtdetq *rte;
        u_long hash;
        int hlen = ip->ip_hl << 2;

        MRTSTAT_INC(mrts_mfc_misses);
        MRTSTAT_INC(mrts_no_route);
        CTR2(KTR_IPMF, "ip_mforward: no mfc for (0x%08x,%lx)",
            ntohl(ip->ip_src.s_addr), (u_long)ntohl(ip->ip_dst.s_addr));

        /*
         * Allocate mbufs early so that we don't do extra work if we are
         * just going to fail anyway.  Make sure to pullup the header so
         * that other people can't step on it.
         */
        rte = (struct rtdetq *)malloc((sizeof *rte), M_MRTABLE,
            M_NOWAIT|M_ZERO);
        if (rte == NULL) {
            MFC_UNLOCK();
            VIF_UNLOCK();
            return ENOBUFS;
        }

        mb0 = m_copypacket(m, M_NOWAIT);
        if (mb0 && (!M_WRITABLE(mb0) || mb0->m_len < hlen))
            mb0 = m_pullup(mb0, hlen);
        if (mb0 == NULL) {
            free(rte, M_MRTABLE);
            MFC_UNLOCK();
            VIF_UNLOCK();
            return ENOBUFS;
        }

        /* is there an upcall waiting for this flow ? */
        hash = MFCHASH(ip->ip_src, ip->ip_dst);
        LIST_FOREACH(rt, &V_mfchashtbl[hash], mfc_hash) {
                if (in_hosteq(ip->ip_src, rt->mfc_origin) &&
                    in_hosteq(ip->ip_dst, rt->mfc_mcastgrp) &&
                    !TAILQ_EMPTY(&rt->mfc_stall))
                        break;
        }

        if (rt == NULL) {
            int i;
            struct igmpmsg *im;
            struct sockaddr_in k_igmpsrc = { sizeof k_igmpsrc, AF_INET };
            struct mbuf *mm;

            /*
             * Locate the vifi for the incoming interface for this packet.
             * If none found, drop packet.
             */
            for (vifi = 0; vifi < V_numvifs &&
                    V_viftable[vifi].v_ifp != ifp; vifi++)
                ;
            if (vifi >= V_numvifs)      /* vif not found, drop packet */
                goto non_fatal;

            /* no upcall, so make a new entry */
            rt = (struct mfc *)malloc(sizeof(*rt), M_MRTABLE, M_NOWAIT);
            if (rt == NULL)
                goto fail;

            /* Make a copy of the header to send to the user level process */
            mm = m_copym(mb0, 0, hlen, M_NOWAIT);
            if (mm == NULL)
                goto fail1;

            /*
             * Send message to routing daemon to install
             * a route into the kernel table
             */

            im = mtod(mm, struct igmpmsg *);
            im->im_msgtype = IGMPMSG_NOCACHE;
            im->im_mbz = 0;
            im->im_vif = vifi;

            MRTSTAT_INC(mrts_upcalls);

            k_igmpsrc.sin_addr = ip->ip_src;
            if (socket_send(V_ip_mrouter, mm, &k_igmpsrc) < 0) {
                CTR0(KTR_IPMF, "ip_mforward: socket queue full");
                MRTSTAT_INC(mrts_upq_sockfull);
fail1:
                free(rt, M_MRTABLE);
fail:
                free(rte, M_MRTABLE);
                m_freem(mb0);
                MFC_UNLOCK();
                VIF_UNLOCK();
                return ENOBUFS;
            }

            /* insert new entry at head of hash chain */
            rt->mfc_origin.s_addr     = ip->ip_src.s_addr;
            rt->mfc_mcastgrp.s_addr   = ip->ip_dst.s_addr;
            rt->mfc_expire            = UPCALL_EXPIRE;
            V_nexpire[hash]++;
            for (i = 0; i < V_numvifs; i++) {
                rt->mfc_ttls[i] = 0;
                rt->mfc_flags[i] = 0;
            }
            rt->mfc_parent = -1;

            /* clear the RP address */
            rt->mfc_rp.s_addr = INADDR_ANY;
            rt->mfc_bw_meter_leq = NULL;
            rt->mfc_bw_meter_geq = NULL;

            /* initialize pkt counters per src-grp */
            rt->mfc_pkt_cnt = 0;
            rt->mfc_byte_cnt = 0;
            rt->mfc_wrong_if = 0;
            timevalclear(&rt->mfc_last_assert);

            TAILQ_INIT(&rt->mfc_stall);
            rt->mfc_nstall = 0;

            /* link into table */
            LIST_INSERT_HEAD(&V_mfchashtbl[hash], rt, mfc_hash);
            TAILQ_INSERT_HEAD(&rt->mfc_stall, rte, rte_link);
            rt->mfc_nstall++;

        } else {
            /* determine if queue has overflowed */
            if (rt->mfc_nstall > MAX_UPQ) {
                MRTSTAT_INC(mrts_upq_ovflw);
non_fatal:
                free(rte, M_MRTABLE);
                m_freem(mb0);
                MFC_UNLOCK();
                VIF_UNLOCK();
                return (0);
            }
            TAILQ_INSERT_TAIL(&rt->mfc_stall, rte, rte_link);
            rt->mfc_nstall++;
        }

        rte->m                  = mb0;
        rte->ifp                = ifp;

        MFC_UNLOCK();
        VIF_UNLOCK();

        return 0;
    }
}

/*
 * Clean up the cache entry if upcall is not serviced
 */
static void
expire_upcalls(void *arg)
{
    u_long i;

    CURVNET_SET((struct vnet *) arg);

    MFC_LOCK();

    for (i = 0; i < mfchashsize; i++) {
        struct mfc *rt, *nrt;

        if (V_nexpire[i] == 0)
            continue;

        LIST_FOREACH_SAFE(rt, &V_mfchashtbl[i], mfc_hash, nrt) {
                if (TAILQ_EMPTY(&rt->mfc_stall))
                        continue;

                if (rt->mfc_expire == 0 || --rt->mfc_expire > 0)
                        continue;

                MRTSTAT_INC(mrts_cache_cleanups);
                CTR3(KTR_IPMF, "%s: expire (%lx, %lx)", __func__,
                    (u_long)ntohl(rt->mfc_origin.s_addr),
                    (u_long)ntohl(rt->mfc_mcastgrp.s_addr));

                expire_mfc(rt);
            }
    }

    MFC_UNLOCK();

    callout_reset(&V_expire_upcalls_ch, EXPIRE_TIMEOUT, expire_upcalls,
        curvnet);

    CURVNET_RESTORE();
}

/*
 * Packet forwarding routine once entry in the cache is made
 */
static int
ip_mdq(struct mbuf *m, struct ifnet *ifp, struct mfc *rt, vifi_t xmt_vif)
{
    struct ip  *ip = mtod(m, struct ip *);
    vifi_t vifi;
    int plen = ntohs(ip->ip_len);

    VIF_LOCK_ASSERT();

    /*
     * If xmt_vif is not -1, send on only the requested vif.
     *
     * (since vifi_t is u_short, -1 becomes MAXUSHORT, which > numvifs.)
     */
    if (xmt_vif < V_numvifs) {
        if (V_viftable[xmt_vif].v_flags & VIFF_REGISTER)
                pim_register_send(ip, V_viftable + xmt_vif, m, rt);
        else
                phyint_send(ip, V_viftable + xmt_vif, m);
        return 1;
    }

    /*
     * Don't forward if it didn't arrive from the parent vif for its origin.
     */
    vifi = rt->mfc_parent;
    if ((vifi >= V_numvifs) || (V_viftable[vifi].v_ifp != ifp)) {
        CTR4(KTR_IPMF, "%s: rx on wrong ifp %p (vifi %d, v_ifp %p)",
            __func__, ifp, (int)vifi, V_viftable[vifi].v_ifp);
        MRTSTAT_INC(mrts_wrong_if);
        ++rt->mfc_wrong_if;
        /*
         * If we are doing PIM assert processing, send a message
         * to the routing daemon.
         *
         * XXX: A PIM-SM router needs the WRONGVIF detection so it
         * can complete the SPT switch, regardless of the type
         * of the iif (broadcast media, GRE tunnel, etc).
         */
        if (V_pim_assert_enabled && (vifi < V_numvifs) &&
            V_viftable[vifi].v_ifp) {
            if (ifp == &V_multicast_register_if)
                PIMSTAT_INC(pims_rcv_registers_wrongiif);

            /* Get vifi for the incoming packet */
            for (vifi = 0; vifi < V_numvifs && V_viftable[vifi].v_ifp != ifp;
                vifi++)
                ;
            if (vifi >= V_numvifs)
                return 0;       /* The iif is not found: ignore the packet. */

            if (rt->mfc_flags[vifi] & MRT_MFC_FLAGS_DISABLE_WRONGVIF)
                return 0;       /* WRONGVIF disabled: ignore the packet */

            if (ratecheck(&rt->mfc_last_assert, &pim_assert_interval)) {
                struct sockaddr_in k_igmpsrc = { sizeof k_igmpsrc, AF_INET };
                struct igmpmsg *im;
                int hlen = ip->ip_hl << 2;
                struct mbuf *mm = m_copym(m, 0, hlen, M_NOWAIT);

                if (mm && (!M_WRITABLE(mm) || mm->m_len < hlen))
                    mm = m_pullup(mm, hlen);
                if (mm == NULL)
                    return ENOBUFS;

                im = mtod(mm, struct igmpmsg *);
                im->im_msgtype  = IGMPMSG_WRONGVIF;
                im->im_mbz              = 0;
                im->im_vif              = vifi;

                MRTSTAT_INC(mrts_upcalls);

                k_igmpsrc.sin_addr = im->im_src;
                if (socket_send(V_ip_mrouter, mm, &k_igmpsrc) < 0) {
                    CTR1(KTR_IPMF, "%s: socket queue full", __func__);
                    MRTSTAT_INC(mrts_upq_sockfull);
                    return ENOBUFS;
                }
            }
        }
        return 0;
    }

    /* If I sourced this packet, it counts as output, else it was input. */
    if (in_hosteq(ip->ip_src, V_viftable[vifi].v_lcl_addr)) {
        V_viftable[vifi].v_pkt_out++;
        V_viftable[vifi].v_bytes_out += plen;
    } else {
        V_viftable[vifi].v_pkt_in++;
        V_viftable[vifi].v_bytes_in += plen;
    }
    rt->mfc_pkt_cnt++;
    rt->mfc_byte_cnt += plen;

    /*
     * For each vif, decide if a copy of the packet should be forwarded.
     * Forward if:
     *          - the ttl exceeds the vif's threshold
     *          - there are group members downstream on interface
     */
    for (vifi = 0; vifi < V_numvifs; vifi++)
        if ((rt->mfc_ttls[vifi] > 0) && (ip->ip_ttl > rt->mfc_ttls[vifi])) {
            V_viftable[vifi].v_pkt_out++;
            V_viftable[vifi].v_bytes_out += plen;
            if (V_viftable[vifi].v_flags & VIFF_REGISTER)
                pim_register_send(ip, V_viftable + vifi, m, rt);
            else
                phyint_send(ip, V_viftable + vifi, m);
        }

    /*
     * Perform upcall-related bw measuring.
     */
    if ((rt->mfc_bw_meter_geq != NULL) || (rt->mfc_bw_meter_leq != NULL)) {
        struct bw_meter *x;
        struct timeval now;

        microtime(&now);
        MFC_LOCK_ASSERT();
        /* Process meters for Greater-or-EQual case */
        for (x = rt->mfc_bw_meter_geq; x != NULL; x = x->bm_mfc_next)
                bw_meter_geq_receive_packet(x, plen, &now);

        /* Process meters for Lower-or-EQual case */
        for (x = rt->mfc_bw_meter_leq; x != NULL; x = x->bm_mfc_next) {
                /* Record that a packet is received */
                x->bm_measured.b_packets++;
                x->bm_measured.b_bytes += plen;
        }
    }

    return 0;
}

/*
 * Check if a vif number is legal/ok. This is used by in_mcast.c.
 */
static int
X_legal_vif_num(int vif)
{
        int ret;

        ret = 0;
        if (vif < 0)
                return (ret);

        VIF_LOCK();
        if (vif < V_numvifs)
                ret = 1;
        VIF_UNLOCK();

        return (ret);
}

/*
 * Return the local address used by this vif
 */
static u_long
X_ip_mcast_src(int vifi)
{
        in_addr_t addr;

        addr = INADDR_ANY;
        if (vifi < 0)
                return (addr);

        VIF_LOCK();
        if (vifi < V_numvifs)
                addr = V_viftable[vifi].v_lcl_addr.s_addr;
        VIF_UNLOCK();

        return (addr);
}

static void
phyint_send(struct ip *ip, struct vif *vifp, struct mbuf *m)
{
    struct mbuf *mb_copy;
    int hlen = ip->ip_hl << 2;

    VIF_LOCK_ASSERT();

    /*
     * Make a new reference to the packet; make sure that
     * the IP header is actually copied, not just referenced,
     * so that ip_output() only scribbles on the copy.
     */
    mb_copy = m_copypacket(m, M_NOWAIT);
    if (mb_copy && (!M_WRITABLE(mb_copy) || mb_copy->m_len < hlen))
        mb_copy = m_pullup(mb_copy, hlen);
    if (mb_copy == NULL)
        return;

    send_packet(vifp, mb_copy);
}

static void
send_packet(struct vif *vifp, struct mbuf *m)
{
        struct ip_moptions imo;
        int error __unused;

        VIF_LOCK_ASSERT();

        imo.imo_multicast_ifp  = vifp->v_ifp;
        imo.imo_multicast_ttl  = mtod(m, struct ip *)->ip_ttl - 1;
        imo.imo_multicast_loop = !!in_mcast_loop;
        imo.imo_multicast_vif  = -1;
        STAILQ_INIT(&imo.imo_head);

        /*
         * Re-entrancy should not be a problem here, because
         * the packets that we send out and are looped back at us
         * should get rejected because they appear to come from
         * the loopback interface, thus preventing looping.
         */
        error = ip_output(m, NULL, NULL, IP_FORWARDING, &imo, NULL);
        CTR3(KTR_IPMF, "%s: vif %td err %d", __func__,
            (ptrdiff_t)(vifp - V_viftable), error);
}

/*
 * Stubs for old RSVP socket shim implementation.
 */

static int
X_ip_rsvp_vif(struct socket *so __unused, struct sockopt *sopt __unused)
{

        return (EOPNOTSUPP);
}

static void
X_ip_rsvp_force_done(struct socket *so __unused)
{

}

static int
X_rsvp_input(struct mbuf **mp, int *offp, int proto)
{
        struct mbuf *m;

        m = *mp;
        *mp = NULL;
        if (!V_rsvp_on)
                m_freem(m);
        return (IPPROTO_DONE);
}

/*
 * Code for bandwidth monitors
 */

/*
 * Define common interface for timeval-related methods
 */
#define BW_TIMEVALCMP(tvp, uvp, cmp) timevalcmp((tvp), (uvp), cmp)
#define BW_TIMEVALDECR(vvp, uvp) timevalsub((vvp), (uvp))
#define BW_TIMEVALADD(vvp, uvp) timevaladd((vvp), (uvp))

static uint32_t
compute_bw_meter_flags(struct bw_upcall *req)
{
    uint32_t flags = 0;

    if (req->bu_flags & BW_UPCALL_UNIT_PACKETS)
        flags |= BW_METER_UNIT_PACKETS;
    if (req->bu_flags & BW_UPCALL_UNIT_BYTES)
        flags |= BW_METER_UNIT_BYTES;
    if (req->bu_flags & BW_UPCALL_GEQ)
        flags |= BW_METER_GEQ;
    if (req->bu_flags & BW_UPCALL_LEQ)
        flags |= BW_METER_LEQ;

    return flags;
}

static void
expire_bw_meter_leq(void *arg)
{
        struct bw_meter *x = arg;
        struct timeval now;
        /*
         * INFO:
         * callout is always executed with MFC_LOCK taken
         */

        CURVNET_SET((struct vnet *)x->arg);

        microtime(&now);

        /*
         * Test if we should deliver an upcall
         */
        if (((x->bm_flags & BW_METER_UNIT_PACKETS) &&
            (x->bm_measured.b_packets <= x->bm_threshold.b_packets)) ||
            ((x->bm_flags & BW_METER_UNIT_BYTES) &&
            (x->bm_measured.b_bytes <= x->bm_threshold.b_bytes))) {
                /* Prepare an upcall for delivery */
                bw_meter_prepare_upcall(x, &now);
        }

        /* Send all upcalls that are pending delivery */
        bw_upcalls_send();

        /* Reset counters */
        x->bm_start_time = now;
        x->bm_measured.b_bytes = 0;
        x->bm_measured.b_packets = 0;

        callout_schedule(&x->bm_meter_callout, tvtohz(&x->bm_threshold.b_time));

        CURVNET_RESTORE();
}

/*
 * Add a bw_meter entry
 */
static int
add_bw_upcall(struct bw_upcall *req)
{
        struct mfc *mfc;
        struct timeval delta = { BW_UPCALL_THRESHOLD_INTERVAL_MIN_SEC,
        BW_UPCALL_THRESHOLD_INTERVAL_MIN_USEC };
        struct timeval now;
        struct bw_meter *x, **bwm_ptr;
        uint32_t flags;

        if (!(V_mrt_api_config & MRT_MFC_BW_UPCALL))
                return EOPNOTSUPP;

        /* Test if the flags are valid */
        if (!(req->bu_flags & (BW_UPCALL_UNIT_PACKETS | BW_UPCALL_UNIT_BYTES)))
                return EINVAL;
        if (!(req->bu_flags & (BW_UPCALL_GEQ | BW_UPCALL_LEQ)))
                return EINVAL;
        if ((req->bu_flags & (BW_UPCALL_GEQ | BW_UPCALL_LEQ))
                        == (BW_UPCALL_GEQ | BW_UPCALL_LEQ))
                return EINVAL;

        /* Test if the threshold time interval is valid */
        if (BW_TIMEVALCMP(&req->bu_threshold.b_time, &delta, <))
                return EINVAL;

        flags = compute_bw_meter_flags(req);

        /*
         * Find if we have already same bw_meter entry
         */
        MFC_LOCK();
        mfc = mfc_find(&req->bu_src, &req->bu_dst);
        if (mfc == NULL) {
                MFC_UNLOCK();
                return EADDRNOTAVAIL;
        }

        /* Choose an appropriate bw_meter list */
        if (req->bu_flags & BW_UPCALL_GEQ)
                bwm_ptr = &mfc->mfc_bw_meter_geq;
        else
                bwm_ptr = &mfc->mfc_bw_meter_leq;

        for (x = *bwm_ptr; x != NULL; x = x->bm_mfc_next) {
                if ((BW_TIMEVALCMP(&x->bm_threshold.b_time,
                    &req->bu_threshold.b_time, ==))
                    && (x->bm_threshold.b_packets
                    == req->bu_threshold.b_packets)
                    && (x->bm_threshold.b_bytes
                    == req->bu_threshold.b_bytes)
                    && (x->bm_flags & BW_METER_USER_FLAGS)
                    == flags) {
                        MFC_UNLOCK();
                        return 0; /* XXX Already installed */
                }
        }

        /* Allocate the new bw_meter entry */
        x = (struct bw_meter*) malloc(sizeof(*x), M_BWMETER, M_NOWAIT);
        if (x == NULL) {
                MFC_UNLOCK();
                return ENOBUFS;
        }

        /* Set the new bw_meter entry */
        x->bm_threshold.b_time = req->bu_threshold.b_time;
        microtime(&now);
        x->bm_start_time = now;
        x->bm_threshold.b_packets = req->bu_threshold.b_packets;
        x->bm_threshold.b_bytes = req->bu_threshold.b_bytes;
        x->bm_measured.b_packets = 0;
        x->bm_measured.b_bytes = 0;
        x->bm_flags = flags;
        x->bm_time_next = NULL;
        x->bm_mfc = mfc;
        x->arg = curvnet;

        /* For LEQ case create periodic callout */
        if (req->bu_flags & BW_UPCALL_LEQ) {
                callout_init_mtx(&x->bm_meter_callout, &mfc_mtx,0);
                callout_reset(&x->bm_meter_callout, tvtohz(&x->bm_threshold.b_time),
                    expire_bw_meter_leq, x);
        }

        /* Add the new bw_meter entry to the front of entries for this MFC */
        x->bm_mfc_next = *bwm_ptr;
        *bwm_ptr = x;

        MFC_UNLOCK();

        return 0;
}

static void
free_bw_list(struct bw_meter *list)
{
    while (list != NULL) {
        struct bw_meter *x = list;

        /* MFC_LOCK must be held here */
        if (x->bm_flags & BW_METER_LEQ)
                callout_drain(&x->bm_meter_callout);

        list = list->bm_mfc_next;
        free(x, M_BWMETER);
    }
}

/*
 * Delete one or multiple bw_meter entries
 */
static int
del_bw_upcall(struct bw_upcall *req)
{
    struct mfc *mfc;
    struct bw_meter *x, **bwm_ptr;

    if (!(V_mrt_api_config & MRT_MFC_BW_UPCALL))
        return EOPNOTSUPP;

    MFC_LOCK();

    /* Find the corresponding MFC entry */
    mfc = mfc_find(&req->bu_src, &req->bu_dst);
    if (mfc == NULL) {
        MFC_UNLOCK();
        return EADDRNOTAVAIL;
    } else if (req->bu_flags & BW_UPCALL_DELETE_ALL) {
        /*
         * Delete all bw_meter entries for this mfc
         */
        struct bw_meter *list;

        /* Free LEQ list */
        list = mfc->mfc_bw_meter_leq;
        mfc->mfc_bw_meter_leq = NULL;
        free_bw_list(list);

        /* Free GEQ list */
        list = mfc->mfc_bw_meter_geq;
        mfc->mfc_bw_meter_geq = NULL;
        free_bw_list(list);
        MFC_UNLOCK();
        return 0;
    } else {                    /* Delete a single bw_meter entry */
        struct bw_meter *prev;
        uint32_t flags = 0;

        flags = compute_bw_meter_flags(req);

        /* Choose an appropriate bw_meter list */
        if (req->bu_flags & BW_UPCALL_GEQ)
                bwm_ptr = &mfc->mfc_bw_meter_geq;
        else
                bwm_ptr = &mfc->mfc_bw_meter_leq;

        /* Find the bw_meter entry to delete */
        for (prev = NULL, x = *bwm_ptr; x != NULL;
             prev = x, x = x->bm_mfc_next) {
            if ((BW_TIMEVALCMP(&x->bm_threshold.b_time,
                               &req->bu_threshold.b_time, ==)) &&
                (x->bm_threshold.b_packets == req->bu_threshold.b_packets) &&
                (x->bm_threshold.b_bytes == req->bu_threshold.b_bytes) &&
                (x->bm_flags & BW_METER_USER_FLAGS) == flags)
                break;
        }
        if (x != NULL) { /* Delete entry from the list for this MFC */
            if (prev != NULL)
                prev->bm_mfc_next = x->bm_mfc_next;     /* remove from middle*/
            else
                *bwm_ptr = x->bm_mfc_next;/* new head of list */

            if (req->bu_flags & BW_UPCALL_LEQ)
                    callout_stop(&x->bm_meter_callout);

            MFC_UNLOCK();
            /* Free the bw_meter entry */
            free(x, M_BWMETER);
            return 0;
        } else {
            MFC_UNLOCK();
            return EINVAL;
        }
    }
    /* NOTREACHED */
}

/*
 * Perform bandwidth measurement processing that may result in an upcall
 */
static void
bw_meter_geq_receive_packet(struct bw_meter *x, int plen, struct timeval *nowp)
{
        struct timeval delta;

        MFC_LOCK_ASSERT();

        delta = *nowp;
        BW_TIMEVALDECR(&delta, &x->bm_start_time);

        /*
         * Processing for ">=" type of bw_meter entry
         */
        if (BW_TIMEVALCMP(&delta, &x->bm_threshold.b_time, >)) {
            /* Reset the bw_meter entry */
            x->bm_start_time = *nowp;
            x->bm_measured.b_packets = 0;
            x->bm_measured.b_bytes = 0;
            x->bm_flags &= ~BW_METER_UPCALL_DELIVERED;
        }

        /* Record that a packet is received */
        x->bm_measured.b_packets++;
        x->bm_measured.b_bytes += plen;

        /*
         * Test if we should deliver an upcall
         */
        if (!(x->bm_flags & BW_METER_UPCALL_DELIVERED)) {
                if (((x->bm_flags & BW_METER_UNIT_PACKETS) &&
                    (x->bm_measured.b_packets >= x->bm_threshold.b_packets)) ||
                    ((x->bm_flags & BW_METER_UNIT_BYTES) &&
                    (x->bm_measured.b_bytes >= x->bm_threshold.b_bytes))) {
                        /* Prepare an upcall for delivery */
                        bw_meter_prepare_upcall(x, nowp);
                        x->bm_flags |= BW_METER_UPCALL_DELIVERED;
                }
        }
}

/*
 * Prepare a bandwidth-related upcall
 */
static void
bw_meter_prepare_upcall(struct bw_meter *x, struct timeval *nowp)
{
        struct timeval delta;
        struct bw_upcall *u;

        MFC_LOCK_ASSERT();

        /*
         * Compute the measured time interval
         */
        delta = *nowp;
        BW_TIMEVALDECR(&delta, &x->bm_start_time);

        /*
         * If there are too many pending upcalls, deliver them now
         */
        if (V_bw_upcalls_n >= BW_UPCALLS_MAX)
                bw_upcalls_send();

        /*
         * Set the bw_upcall entry
         */
        u = &V_bw_upcalls[V_bw_upcalls_n++];
        u->bu_src = x->bm_mfc->mfc_origin;
        u->bu_dst = x->bm_mfc->mfc_mcastgrp;
        u->bu_threshold.b_time = x->bm_threshold.b_time;
        u->bu_threshold.b_packets = x->bm_threshold.b_packets;
        u->bu_threshold.b_bytes = x->bm_threshold.b_bytes;
        u->bu_measured.b_time = delta;
        u->bu_measured.b_packets = x->bm_measured.b_packets;
        u->bu_measured.b_bytes = x->bm_measured.b_bytes;
        u->bu_flags = 0;
        if (x->bm_flags & BW_METER_UNIT_PACKETS)
                u->bu_flags |= BW_UPCALL_UNIT_PACKETS;
        if (x->bm_flags & BW_METER_UNIT_BYTES)
                u->bu_flags |= BW_UPCALL_UNIT_BYTES;
        if (x->bm_flags & BW_METER_GEQ)
                u->bu_flags |= BW_UPCALL_GEQ;
        if (x->bm_flags & BW_METER_LEQ)
                u->bu_flags |= BW_UPCALL_LEQ;
}

/*
 * Send the pending bandwidth-related upcalls
 */
static void
bw_upcalls_send(void)
{
    struct mbuf *m;
    int len = V_bw_upcalls_n * sizeof(V_bw_upcalls[0]);
    struct sockaddr_in k_igmpsrc = { sizeof k_igmpsrc, AF_INET };
    static struct igmpmsg igmpmsg = { 0,                /* unused1 */
                                      0,                /* unused2 */
                                      IGMPMSG_BW_UPCALL,/* im_msgtype */
                                      0,                /* im_mbz  */
                                      0,                /* im_vif  */
                                      0,                /* unused3 */
                                      { 0 },            /* im_src  */
                                      { 0 } };          /* im_dst  */

    MFC_LOCK_ASSERT();

    if (V_bw_upcalls_n == 0)
        return;                 /* No pending upcalls */

    V_bw_upcalls_n = 0;

    /*
     * Allocate a new mbuf, initialize it with the header and
     * the payload for the pending calls.
     */
    m = m_gethdr(M_NOWAIT, MT_DATA);
    if (m == NULL) {
        log(LOG_WARNING, "bw_upcalls_send: cannot allocate mbuf\n");
        return;
    }

    m_copyback(m, 0, sizeof(struct igmpmsg), (caddr_t)&igmpmsg);
    m_copyback(m, sizeof(struct igmpmsg), len, (caddr_t)&V_bw_upcalls[0]);

    /*
     * Send the upcalls
     * XXX do we need to set the address in k_igmpsrc ?
     */
    MRTSTAT_INC(mrts_upcalls);
    if (socket_send(V_ip_mrouter, m, &k_igmpsrc) < 0) {
        log(LOG_WARNING, "bw_upcalls_send: ip_mrouter socket queue full\n");
        MRTSTAT_INC(mrts_upq_sockfull);
    }
}

/*
 * A periodic function for sending all upcalls that are pending delivery
 */
static void
expire_bw_upcalls_send(void *arg)
{
    CURVNET_SET((struct vnet *) arg);

    MFC_LOCK();
    bw_upcalls_send();
    MFC_UNLOCK();

    callout_reset(&V_bw_upcalls_ch, BW_UPCALLS_PERIOD, expire_bw_upcalls_send,
        curvnet);
    CURVNET_RESTORE();
}

/*
 * End of bandwidth monitoring code
 */

/*
 * Send the packet up to the user daemon, or eventually do kernel encapsulation
 *
 */
static int
pim_register_send(struct ip *ip, struct vif *vifp, struct mbuf *m,
    struct mfc *rt)
{
    struct mbuf *mb_copy, *mm;

    /*
     * Do not send IGMP_WHOLEPKT notifications to userland, if the
     * rendezvous point was unspecified, and we were told not to.
     */
    if (pim_squelch_wholepkt != 0 && (V_mrt_api_config & MRT_MFC_RP) &&
        in_nullhost(rt->mfc_rp))
        return 0;

    mb_copy = pim_register_prepare(ip, m);
    if (mb_copy == NULL)
        return ENOBUFS;

    /*
     * Send all the fragments. Note that the mbuf for each fragment
     * is freed by the sending machinery.
     */
    for (mm = mb_copy; mm; mm = mb_copy) {
        mb_copy = mm->m_nextpkt;
        mm->m_nextpkt = 0;
        mm = m_pullup(mm, sizeof(struct ip));
        if (mm != NULL) {
            ip = mtod(mm, struct ip *);
            if ((V_mrt_api_config & MRT_MFC_RP) && !in_nullhost(rt->mfc_rp)) {
                pim_register_send_rp(ip, vifp, mm, rt);
            } else {
                pim_register_send_upcall(ip, vifp, mm, rt);
            }
        }
    }

    return 0;
}

/*
 * Return a copy of the data packet that is ready for PIM Register
 * encapsulation.
 * XXX: Note that in the returned copy the IP header is a valid one.
 */
static struct mbuf *
pim_register_prepare(struct ip *ip, struct mbuf *m)
{
    struct mbuf *mb_copy = NULL;
    int mtu;

    /* Take care of delayed checksums */
    if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
        in_delayed_cksum(m);
        m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
    }

    /*
     * Copy the old packet & pullup its IP header into the
     * new mbuf so we can modify it.
     */
    mb_copy = m_copypacket(m, M_NOWAIT);
    if (mb_copy == NULL)
        return NULL;
    mb_copy = m_pullup(mb_copy, ip->ip_hl << 2);
    if (mb_copy == NULL)
        return NULL;

    /* take care of the TTL */
    ip = mtod(mb_copy, struct ip *);
    --ip->ip_ttl;

    /* Compute the MTU after the PIM Register encapsulation */
    mtu = 0xffff - sizeof(pim_encap_iphdr) - sizeof(pim_encap_pimhdr);

    if (ntohs(ip->ip_len) <= mtu) {
        /* Turn the IP header into a valid one */
        ip->ip_sum = 0;
        ip->ip_sum = in_cksum(mb_copy, ip->ip_hl << 2);
    } else {
        /* Fragment the packet */
        mb_copy->m_pkthdr.csum_flags |= CSUM_IP;
        if (ip_fragment(ip, &mb_copy, mtu, 0) != 0) {
            m_freem(mb_copy);
            return NULL;
        }
    }
    return mb_copy;
}

/*
 * Send an upcall with the data packet to the user-level process.
 */
static int
pim_register_send_upcall(struct ip *ip, struct vif *vifp,
    struct mbuf *mb_copy, struct mfc *rt)
{
    struct mbuf *mb_first;
    int len = ntohs(ip->ip_len);
    struct igmpmsg *im;
    struct sockaddr_in k_igmpsrc = { sizeof k_igmpsrc, AF_INET };

    VIF_LOCK_ASSERT();

    /*
     * Add a new mbuf with an upcall header
     */
    mb_first = m_gethdr(M_NOWAIT, MT_DATA);
    if (mb_first == NULL) {
        m_freem(mb_copy);
        return ENOBUFS;
    }
    mb_first->m_data += max_linkhdr;
    mb_first->m_pkthdr.len = len + sizeof(struct igmpmsg);
    mb_first->m_len = sizeof(struct igmpmsg);
    mb_first->m_next = mb_copy;

    /* Send message to routing daemon */
    im = mtod(mb_first, struct igmpmsg *);
    im->im_msgtype      = IGMPMSG_WHOLEPKT;
    im->im_mbz          = 0;
    im->im_vif          = vifp - V_viftable;
    im->im_src          = ip->ip_src;
    im->im_dst          = ip->ip_dst;

    k_igmpsrc.sin_addr  = ip->ip_src;

    MRTSTAT_INC(mrts_upcalls);

    if (socket_send(V_ip_mrouter, mb_first, &k_igmpsrc) < 0) {
        CTR1(KTR_IPMF, "%s: socket queue full", __func__);
        MRTSTAT_INC(mrts_upq_sockfull);
        return ENOBUFS;
    }

    /* Keep statistics */
    PIMSTAT_INC(pims_snd_registers_msgs);
    PIMSTAT_ADD(pims_snd_registers_bytes, len);

    return 0;
}

/*
 * Encapsulate the data packet in PIM Register message and send it to the RP.
 */
static int
pim_register_send_rp(struct ip *ip, struct vif *vifp, struct mbuf *mb_copy,
    struct mfc *rt)
{
    struct mbuf *mb_first;
    struct ip *ip_outer;
    struct pim_encap_pimhdr *pimhdr;
    int len = ntohs(ip->ip_len);
    vifi_t vifi = rt->mfc_parent;

    VIF_LOCK_ASSERT();

    if ((vifi >= V_numvifs) || in_nullhost(V_viftable[vifi].v_lcl_addr)) {
        m_freem(mb_copy);
        return EADDRNOTAVAIL;           /* The iif vif is invalid */
    }

    /*
     * Add a new mbuf with the encapsulating header
     */
    mb_first = m_gethdr(M_NOWAIT, MT_DATA);
    if (mb_first == NULL) {
        m_freem(mb_copy);
        return ENOBUFS;
    }
    mb_first->m_data += max_linkhdr;
    mb_first->m_len = sizeof(pim_encap_iphdr) + sizeof(pim_encap_pimhdr);
    mb_first->m_next = mb_copy;

    mb_first->m_pkthdr.len = len + mb_first->m_len;

    /*
     * Fill in the encapsulating IP and PIM header
     */
    ip_outer = mtod(mb_first, struct ip *);
    *ip_outer = pim_encap_iphdr;
    ip_outer->ip_len = htons(len + sizeof(pim_encap_iphdr) +
        sizeof(pim_encap_pimhdr));
    ip_outer->ip_src = V_viftable[vifi].v_lcl_addr;
    ip_outer->ip_dst = rt->mfc_rp;
    /*
     * Copy the inner header TOS to the outer header, and take care of the
     * IP_DF bit.
     */
    ip_outer->ip_tos = ip->ip_tos;
    if (ip->ip_off & htons(IP_DF))
        ip_outer->ip_off |= htons(IP_DF);
    ip_fillid(ip_outer);
    pimhdr = (struct pim_encap_pimhdr *)((caddr_t)ip_outer
                                         + sizeof(pim_encap_iphdr));
    *pimhdr = pim_encap_pimhdr;
    /* If the iif crosses a border, set the Border-bit */
    if (rt->mfc_flags[vifi] & MRT_MFC_FLAGS_BORDER_VIF & V_mrt_api_config)
        pimhdr->flags |= htonl(PIM_BORDER_REGISTER);

    mb_first->m_data += sizeof(pim_encap_iphdr);
    pimhdr->pim.pim_cksum = in_cksum(mb_first, sizeof(pim_encap_pimhdr));
    mb_first->m_data -= sizeof(pim_encap_iphdr);

    send_packet(vifp, mb_first);

    /* Keep statistics */
    PIMSTAT_INC(pims_snd_registers_msgs);
    PIMSTAT_ADD(pims_snd_registers_bytes, len);

    return 0;
}

/*
 * pim_encapcheck() is called by the encap4_input() path at runtime to
 * determine if a packet is for PIM; allowing PIM to be dynamically loaded
 * into the kernel.
 */
static int
pim_encapcheck(const struct mbuf *m __unused, int off __unused,
    int proto __unused, void *arg __unused)
{

    KASSERT(proto == IPPROTO_PIM, ("not for IPPROTO_PIM"));
    return (8);         /* claim the datagram. */
}

/*
 * PIM-SMv2 and PIM-DM messages processing.
 * Receives and verifies the PIM control messages, and passes them
 * up to the listening socket, using rip_input().
 * The only message with special processing is the PIM_REGISTER message
 * (used by PIM-SM): the PIM header is stripped off, and the inner packet
 * is passed to if_simloop().
 */
static int
pim_input(struct mbuf *m, int off, int proto, void *arg __unused)
{
    struct ip *ip = mtod(m, struct ip *);
    struct pim *pim;
    int iphlen = off;
    int minlen;
    int datalen = ntohs(ip->ip_len) - iphlen;
    int ip_tos;

    /* Keep statistics */
    PIMSTAT_INC(pims_rcv_total_msgs);
    PIMSTAT_ADD(pims_rcv_total_bytes, datalen);

    /*
     * Validate lengths
     */
    if (datalen < PIM_MINLEN) {
        PIMSTAT_INC(pims_rcv_tooshort);
        CTR3(KTR_IPMF, "%s: short packet (%d) from 0x%08x",
            __func__, datalen, ntohl(ip->ip_src.s_addr));
        m_freem(m);
        return (IPPROTO_DONE);
    }

    /*
     * If the packet is at least as big as a REGISTER, go agead
     * and grab the PIM REGISTER header size, to avoid another
     * possible m_pullup() later.
     *
     * PIM_MINLEN       == pimhdr + u_int32_t == 4 + 4 = 8
     * PIM_REG_MINLEN   == pimhdr + reghdr + encap_iphdr == 4 + 4 + 20 = 28
     */
    minlen = iphlen + (datalen >= PIM_REG_MINLEN ? PIM_REG_MINLEN : PIM_MINLEN);
    /*
     * Get the IP and PIM headers in contiguous memory, and
     * possibly the PIM REGISTER header.
     */
    if (m->m_len < minlen && (m = m_pullup(m, minlen)) == NULL) {
        CTR1(KTR_IPMF, "%s: m_pullup() failed", __func__);
        return (IPPROTO_DONE);
    }

    /* m_pullup() may have given us a new mbuf so reset ip. */
    ip = mtod(m, struct ip *);
    ip_tos = ip->ip_tos;

    /* adjust mbuf to point to the PIM header */
    m->m_data += iphlen;
    m->m_len  -= iphlen;
    pim = mtod(m, struct pim *);

    /*
     * Validate checksum. If PIM REGISTER, exclude the data packet.
     *
     * XXX: some older PIMv2 implementations don't make this distinction,
     * so for compatibility reason perform the checksum over part of the
     * message, and if error, then over the whole message.
     */
    if (PIM_VT_T(pim->pim_vt) == PIM_REGISTER && in_cksum(m, PIM_MINLEN) == 0) {
        /* do nothing, checksum okay */
    } else if (in_cksum(m, datalen)) {
        PIMSTAT_INC(pims_rcv_badsum);
        CTR1(KTR_IPMF, "%s: invalid checksum", __func__);
        m_freem(m);
        return (IPPROTO_DONE);
    }

    /* PIM version check */
    if (PIM_VT_V(pim->pim_vt) < PIM_VERSION) {
        PIMSTAT_INC(pims_rcv_badversion);
        CTR3(KTR_IPMF, "%s: bad version %d expect %d", __func__,
            (int)PIM_VT_V(pim->pim_vt), PIM_VERSION);
        m_freem(m);
        return (IPPROTO_DONE);
    }

    /* restore mbuf back to the outer IP */
    m->m_data -= iphlen;
    m->m_len  += iphlen;

    if (PIM_VT_T(pim->pim_vt) == PIM_REGISTER) {
        /*
         * Since this is a REGISTER, we'll make a copy of the register
         * headers ip + pim + u_int32 + encap_ip, to be passed up to the
         * routing daemon.
         */
        struct sockaddr_in dst = { sizeof(dst), AF_INET };
        struct mbuf *mcp;
        struct ip *encap_ip;
        u_int32_t *reghdr;
        struct ifnet *vifp;

        VIF_LOCK();
        if ((V_reg_vif_num >= V_numvifs) || (V_reg_vif_num == VIFI_INVALID)) {
            VIF_UNLOCK();
            CTR2(KTR_IPMF, "%s: register vif not set: %d", __func__,
                (int)V_reg_vif_num);
            m_freem(m);
            return (IPPROTO_DONE);
        }
        /* XXX need refcnt? */
        vifp = V_viftable[V_reg_vif_num].v_ifp;
        VIF_UNLOCK();

        /*
         * Validate length
         */
        if (datalen < PIM_REG_MINLEN) {
            PIMSTAT_INC(pims_rcv_tooshort);
            PIMSTAT_INC(pims_rcv_badregisters);
            CTR1(KTR_IPMF, "%s: register packet size too small", __func__);
            m_freem(m);
            return (IPPROTO_DONE);
        }

        reghdr = (u_int32_t *)(pim + 1);
        encap_ip = (struct ip *)(reghdr + 1);

        CTR3(KTR_IPMF, "%s: register: encap ip src 0x%08x len %d",
            __func__, ntohl(encap_ip->ip_src.s_addr),
            ntohs(encap_ip->ip_len));

        /* verify the version number of the inner packet */
        if (encap_ip->ip_v != IPVERSION) {
            PIMSTAT_INC(pims_rcv_badregisters);
            CTR1(KTR_IPMF, "%s: bad encap ip version", __func__);
            m_freem(m);
            return (IPPROTO_DONE);
        }

        /* verify the inner packet is destined to a mcast group */
        if (!IN_MULTICAST(ntohl(encap_ip->ip_dst.s_addr))) {
            PIMSTAT_INC(pims_rcv_badregisters);
            CTR2(KTR_IPMF, "%s: bad encap ip dest 0x%08x", __func__,
                ntohl(encap_ip->ip_dst.s_addr));
            m_freem(m);
            return (IPPROTO_DONE);
        }

        /* If a NULL_REGISTER, pass it to the daemon */
        if ((ntohl(*reghdr) & PIM_NULL_REGISTER))
            goto pim_input_to_daemon;

        /*
         * Copy the TOS from the outer IP header to the inner IP header.
         */
        if (encap_ip->ip_tos != ip_tos) {
            /* Outer TOS -> inner TOS */
            encap_ip->ip_tos = ip_tos;
            /* Recompute the inner header checksum. Sigh... */

            /* adjust mbuf to point to the inner IP header */
            m->m_data += (iphlen + PIM_MINLEN);
            m->m_len  -= (iphlen + PIM_MINLEN);

            encap_ip->ip_sum = 0;
            encap_ip->ip_sum = in_cksum(m, encap_ip->ip_hl << 2);

            /* restore mbuf to point back to the outer IP header */
            m->m_data -= (iphlen + PIM_MINLEN);
            m->m_len  += (iphlen + PIM_MINLEN);
        }

        /*
         * Decapsulate the inner IP packet and loopback to forward it
         * as a normal multicast packet. Also, make a copy of the
         *     outer_iphdr + pimhdr + reghdr + encap_iphdr
         * to pass to the daemon later, so it can take the appropriate
         * actions (e.g., send back PIM_REGISTER_STOP).
         * XXX: here m->m_data points to the outer IP header.
         */
        mcp = m_copym(m, 0, iphlen + PIM_REG_MINLEN, M_NOWAIT);
        if (mcp == NULL) {
            CTR1(KTR_IPMF, "%s: m_copym() failed", __func__);
            m_freem(m);
            return (IPPROTO_DONE);
        }

        /* Keep statistics */
        /* XXX: registers_bytes include only the encap. mcast pkt */
        PIMSTAT_INC(pims_rcv_registers_msgs);
        PIMSTAT_ADD(pims_rcv_registers_bytes, ntohs(encap_ip->ip_len));

        /*
         * forward the inner ip packet; point m_data at the inner ip.
         */
        m_adj(m, iphlen + PIM_MINLEN);

        CTR4(KTR_IPMF,
            "%s: forward decap'd REGISTER: src %lx dst %lx vif %d",
            __func__,
            (u_long)ntohl(encap_ip->ip_src.s_addr),
            (u_long)ntohl(encap_ip->ip_dst.s_addr),
            (int)V_reg_vif_num);

        /* NB: vifp was collected above; can it change on us? */
        if_simloop(vifp, m, dst.sin_family, 0);

        /* prepare the register head to send to the mrouting daemon */
        m = mcp;
    }

pim_input_to_daemon:
    /*
     * Pass the PIM message up to the daemon; if it is a Register message,
     * pass the 'head' only up to the daemon. This includes the
     * outer IP header, PIM header, PIM-Register header and the
     * inner IP header.
     * XXX: the outer IP header pkt size of a Register is not adjust to
     * reflect the fact that the inner multicast data is truncated.
     */
    return (rip_input(&m, &off, proto));
}

static int
sysctl_mfctable(SYSCTL_HANDLER_ARGS)
{
        struct mfc      *rt;
        int              error, i;

        if (req->newptr)
                return (EPERM);
        if (V_mfchashtbl == NULL)       /* XXX unlocked */
                return (0);
        error = sysctl_wire_old_buffer(req, 0);
        if (error)
                return (error);

        MFC_LOCK();
        for (i = 0; i < mfchashsize; i++) {
                LIST_FOREACH(rt, &V_mfchashtbl[i], mfc_hash) {
                        error = SYSCTL_OUT(req, rt, sizeof(struct mfc));
                        if (error)
                                goto out_locked;
                }
        }
out_locked:
        MFC_UNLOCK();
        return (error);
}

static SYSCTL_NODE(_net_inet_ip, OID_AUTO, mfctable,
    CTLFLAG_RD | CTLFLAG_MPSAFE, sysctl_mfctable,
    "IPv4 Multicast Forwarding Table "
    "(struct *mfc[mfchashsize], netinet/ip_mroute.h)");

static int
sysctl_viflist(SYSCTL_HANDLER_ARGS)
{
        int error;

        if (req->newptr)
                return (EPERM);
        if (V_viftable == NULL)         /* XXX unlocked */
                return (0);
        error = sysctl_wire_old_buffer(req, sizeof(*V_viftable) * MAXVIFS);
        if (error)
                return (error);

        VIF_LOCK();
        error = SYSCTL_OUT(req, V_viftable, sizeof(*V_viftable) * MAXVIFS);
        VIF_UNLOCK();
        return (error);
}

SYSCTL_PROC(_net_inet_ip, OID_AUTO, viftable,
    CTLTYPE_OPAQUE | CTLFLAG_VNET | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
    sysctl_viflist, "S,vif[MAXVIFS]",
    "IPv4 Multicast Interfaces (struct vif[MAXVIFS], netinet/ip_mroute.h)");

static void
vnet_mroute_init(const void *unused __unused)
{

        V_nexpire = malloc(mfchashsize, M_MRTABLE, M_WAITOK|M_ZERO);

        V_viftable = mallocarray(MAXVIFS, sizeof(*V_viftable),
            M_MRTABLE, M_WAITOK|M_ZERO);
        V_bw_upcalls = mallocarray(BW_UPCALLS_MAX, sizeof(*V_bw_upcalls),
            M_MRTABLE, M_WAITOK|M_ZERO);

        callout_init(&V_expire_upcalls_ch, 1);
        callout_init(&V_bw_upcalls_ch, 1);
}

VNET_SYSINIT(vnet_mroute_init, SI_SUB_PROTO_MC, SI_ORDER_ANY, vnet_mroute_init,
        NULL);

static void
vnet_mroute_uninit(const void *unused __unused)
{

        free(V_bw_upcalls, M_MRTABLE);
        free(V_viftable, M_MRTABLE);
        free(V_nexpire, M_MRTABLE);
        V_nexpire = NULL;
}

VNET_SYSUNINIT(vnet_mroute_uninit, SI_SUB_PROTO_MC, SI_ORDER_MIDDLE,
        vnet_mroute_uninit, NULL);

static int
ip_mroute_modevent(module_t mod, int type, void *unused)
{

    switch (type) {
    case MOD_LOAD:
        MROUTER_LOCK_INIT();

        if_detach_event_tag = EVENTHANDLER_REGISTER(ifnet_departure_event,
            if_detached_event, NULL, EVENTHANDLER_PRI_ANY);
        if (if_detach_event_tag == NULL) {
                printf("ip_mroute: unable to register "
                    "ifnet_departure_event handler\n");
                MROUTER_LOCK_DESTROY();
                return (EINVAL);
        }

        MFC_LOCK_INIT();
        VIF_LOCK_INIT();

        mfchashsize = MFCHASHSIZE;
        if (TUNABLE_ULONG_FETCH("net.inet.ip.mfchashsize", &mfchashsize) &&
            !powerof2(mfchashsize)) {
                printf("WARNING: %s not a power of 2; using default\n",
                    "net.inet.ip.mfchashsize");
                mfchashsize = MFCHASHSIZE;
        }

        pim_squelch_wholepkt = 0;
        TUNABLE_ULONG_FETCH("net.inet.pim.squelch_wholepkt",
            &pim_squelch_wholepkt);

        pim_encap_cookie = ip_encap_attach(&ipv4_encap_cfg, NULL, M_WAITOK);
        if (pim_encap_cookie == NULL) {
                printf("ip_mroute: unable to attach pim encap\n");
                VIF_LOCK_DESTROY();
                MFC_LOCK_DESTROY();
                MROUTER_LOCK_DESTROY();
                return (EINVAL);
        }

        ip_mcast_src = X_ip_mcast_src;
        ip_mforward = X_ip_mforward;
        ip_mrouter_done = X_ip_mrouter_done;
        ip_mrouter_get = X_ip_mrouter_get;
        ip_mrouter_set = X_ip_mrouter_set;

        ip_rsvp_force_done = X_ip_rsvp_force_done;
        ip_rsvp_vif = X_ip_rsvp_vif;

        legal_vif_num = X_legal_vif_num;
        mrt_ioctl = X_mrt_ioctl;
        rsvp_input_p = X_rsvp_input;
        break;

    case MOD_UNLOAD:
        /*
         * Typically module unload happens after the user-level
         * process has shutdown the kernel services (the check
         * below insures someone can't just yank the module out
         * from under a running process).  But if the module is
         * just loaded and then unloaded w/o starting up a user
         * process we still need to cleanup.
         */
        MROUTER_LOCK();
        if (ip_mrouter_cnt != 0) {
            MROUTER_UNLOCK();
            return (EINVAL);
        }
        ip_mrouter_unloading = 1;
        MROUTER_UNLOCK();

        EVENTHANDLER_DEREGISTER(ifnet_departure_event, if_detach_event_tag);

        if (pim_encap_cookie) {
            ip_encap_detach(pim_encap_cookie);
            pim_encap_cookie = NULL;
        }

        ip_mcast_src = NULL;
        ip_mforward = NULL;
        ip_mrouter_done = NULL;
        ip_mrouter_get = NULL;
        ip_mrouter_set = NULL;

        ip_rsvp_force_done = NULL;
        ip_rsvp_vif = NULL;

        legal_vif_num = NULL;
        mrt_ioctl = NULL;
        rsvp_input_p = NULL;

        VIF_LOCK_DESTROY();
        MFC_LOCK_DESTROY();
        MROUTER_LOCK_DESTROY();
        break;

    default:
        return EOPNOTSUPP;
    }
    return 0;
}

static moduledata_t ip_mroutemod = {
    "ip_mroute",
    ip_mroute_modevent,
    0
};

DECLARE_MODULE(ip_mroute, ip_mroutemod, SI_SUB_PROTO_MC, SI_ORDER_MIDDLE);