/*      $NetBSD: ip6_mroute.c,v 1.133 2025/01/02 16:10:22 andvar Exp $  */
/*      $KAME: ip6_mroute.c,v 1.49 2001/07/25 09:21:18 jinmei Exp $     */

/*
 * Copyright (C) 1998 WIDE Project.
 * All rights reserved.
 *
 * 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 project 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 PROJECT 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 PROJECT 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.
 */

/*      BSDI ip_mroute.c,v 2.10 1996/11/14 00:29:52 jch Exp     */

/*
 * 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
 */

/*
 * Copyright (c) 1989 Stephen Deering
 *
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 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.
 *
 *      @(#)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 1994
 *
 * MROUTING Revision: 3.5.1.2 + PIM-SMv2 (pimd) Support
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: ip6_mroute.c,v 1.133 2025/01/02 16:10:22 andvar Exp $");

#ifdef _KERNEL_OPT
#include "opt_inet.h"
#include "opt_mrouting.h"
#endif

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/callout.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sockio.h>
#include <sys/errno.h>
#include <sys/time.h>
#include <sys/kernel.h>
#include <sys/ioctl.h>
#include <sys/sysctl.h>
#include <sys/syslog.h>

#include <net/if.h>
#include <net/route.h>
#include <net/raw_cb.h>
#include <net/net_stats.h>

#include <netinet/in.h>
#include <netinet/in_var.h>
#include <netinet/icmp6.h>

#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
#include <netinet6/ip6_private.h>
#include <netinet6/ip6_mroute.h>
#include <netinet6/scope6_var.h>
#include <netinet6/pim6.h>
#include <netinet6/pim6_var.h>
#include <netinet6/nd6.h>

static int ip6_mdq(struct mbuf *, struct ifnet *, struct mf6c *);
static void phyint_send(struct ip6_hdr *, struct mif6 *, struct mbuf *);

static int set_pim6(int *);
static int socket_send(struct socket *, struct mbuf *, struct sockaddr_in6 *);
static int register_send(struct ip6_hdr *, struct mif6 *, struct mbuf *);

/*
 * Globals.  All but ip6_mrouter, ip6_mrtproto and mrt6stat could be static,
 * except for netstat or debugging purposes.
 */
struct socket  *ip6_mrouter = NULL;
int             ip6_mrouter_ver = 0;
int             ip6_mrtproto = IPPROTO_PIM;    /* for netstat only */
struct mrt6stat mrt6stat;

#define NO_RTE_FOUND    0x1
#define RTE_FOUND       0x2

struct mf6c     *mf6ctable[MF6CTBLSIZ];
u_char          n6expire[MF6CTBLSIZ];
struct mif6 mif6table[MAXMIFS];
#ifdef MRT6DEBUG
u_int           mrt6debug = 0;    /* debug level        */
#define DEBUG_MFC       0x02
#define DEBUG_FORWARD   0x04
#define DEBUG_EXPIRE    0x08
#define DEBUG_XMIT      0x10
#define DEBUG_REG       0x20
#define DEBUG_PIM       0x40
#define __mrt6debugused     /* empty */
#else
#define __mrt6debugused     __unused
#endif

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

#ifdef INET
#ifdef MROUTING
extern struct socket *ip_mrouter;
#endif
#endif

/*
 * 'Interfaces' associated with decapsulator (so we can tell
 * packets that went through it from ones that get reflected
 * by a broken gateway).  These interfaces are never linked into
 * the system ifnet list & no routes point to them.  I.e., packets
 * can't be sent this way.  They only exist as a placeholder for
 * multicast source verification.
 */
struct ifnet multicast_register_if6;

#define ENCAP_HOPS 64

/*
 * Private variables.
 */
static mifi_t nummifs = 0;
static mifi_t reg_mif_num = (mifi_t)-1;

static percpu_t *pim6stat_percpu;

#define PIM6_STATINC(x)         _NET_STATINC(pim6stat_percpu, x)

static int pim6;

/*
 * Hash function for a source, group entry
 */
#define MF6CHASH(a, g) MF6CHASHMOD((a).s6_addr32[0] ^ (a).s6_addr32[1] ^ \
                                   (a).s6_addr32[2] ^ (a).s6_addr32[3] ^ \
                                   (g).s6_addr32[0] ^ (g).s6_addr32[1] ^ \
                                   (g).s6_addr32[2] ^ (g).s6_addr32[3])

/*
 * Find a route for a given origin IPv6 address and Multicast group address.
 * Quality of service parameter to be added in the future!!!
 */

#define MF6CFIND(o, g, rt) do { \
        struct mf6c *_rt = mf6ctable[MF6CHASH(o,g)]; \
        rt = NULL; \
        mrt6stat.mrt6s_mfc_lookups++; \
        while (_rt) { \
                if (IN6_ARE_ADDR_EQUAL(&_rt->mf6c_origin.sin6_addr, &(o)) && \
                    IN6_ARE_ADDR_EQUAL(&_rt->mf6c_mcastgrp.sin6_addr, &(g)) && \
                    (_rt->mf6c_stall == NULL)) { \
                        rt = _rt; \
                        break; \
                } \
                _rt = _rt->mf6c_next; \
        } \
        if (rt == NULL) { \
                mrt6stat.mrt6s_mfc_misses++; \
        } \
} while (/*CONSTCOND*/ 0)

/*
 * Macros to compute elapsed time efficiently
 * Borrowed from Van Jacobson's scheduling code
 */
#define TV_DELTA(a, b, delta) do { \
            int xxs; \
                \
            delta = (a).tv_usec - (b).tv_usec; \
            if ((xxs = (a).tv_sec - (b).tv_sec)) { \
               switch (xxs) { \
                      case 2: \
                          delta += 1000000; \
                              /* FALLTHROUGH */ \
                      case 1: \
                          delta += 1000000; \
                          break; \
                      default: \
                          delta += (1000000 * xxs); \
               } \
            } \
} while (/*CONSTCOND*/ 0)

#define TV_LT(a, b) (((a).tv_usec < (b).tv_usec && \
              (a).tv_sec <= (b).tv_sec) || (a).tv_sec < (b).tv_sec)

#ifdef UPCALL_TIMING
#define UPCALL_MAX      50
u_long upcall_data[UPCALL_MAX + 1];
static void collate();
#endif /* UPCALL_TIMING */

static int get_sg_cnt(struct sioc_sg_req6 *);
static int get_mif6_cnt(struct sioc_mif_req6 *);
static int ip6_mrouter_init(struct socket *, int, int);
static int add_m6if(struct mif6ctl *);
static int del_m6if(mifi_t *);
static int add_m6fc(struct mf6cctl *);
static int del_m6fc(struct mf6cctl *);
static void sysctl_net_inet6_pim6_setup(struct sysctllog **);

static callout_t expire_upcalls_ch;

void
pim6_init(void)
{

        sysctl_net_inet6_pim6_setup(NULL);
        pim6stat_percpu = percpu_alloc(sizeof(uint64_t) * PIM6_NSTATS);
}

/*
 * Handle MRT setsockopt commands to modify the multicast routing tables.
 */
int
ip6_mrouter_set(struct socket *so, struct sockopt *sopt)
{
        int error, optval;
        struct mif6ctl mifc;
        struct mf6cctl mfcc;
        mifi_t mifi;

        if (sopt->sopt_name != MRT6_INIT && so != ip6_mrouter)
                return (EACCES);

        error = 0;

        switch (sopt->sopt_name) {
#ifdef MRT6_OINIT
        case MRT6_OINIT:
#endif
        case MRT6_INIT:
                error = sockopt_getint(sopt, &optval);
                if (error)
                        break;
                return (ip6_mrouter_init(so, optval, sopt->sopt_name));
        case MRT6_DONE:
                return (ip6_mrouter_done());
        case MRT6_ADD_MIF:
                error = sockopt_get(sopt, &mifc, sizeof(mifc));
                if (error)
                        break;
                return (add_m6if(&mifc));
        case MRT6_DEL_MIF:
                error = sockopt_get(sopt, &mifi, sizeof(mifi));
                if (error)
                        break;
                return (del_m6if(&mifi));
        case MRT6_ADD_MFC:
                error = sockopt_get(sopt, &mfcc, sizeof(mfcc));
                if (error)
                        break;
                return (add_m6fc(&mfcc));
        case MRT6_DEL_MFC:
                error = sockopt_get(sopt, &mfcc, sizeof(mfcc));
                if (error)
                        break;
                return (del_m6fc(&mfcc));
        case MRT6_PIM:
                error = sockopt_getint(sopt, &optval);
                if (error)
                        break;
                return (set_pim6(&optval));
        default:
                error = EOPNOTSUPP;
        }

        return (error);
}

/*
 * Handle MRT getsockopt commands
 */
int
ip6_mrouter_get(struct socket *so, struct sockopt *sopt)
{
        int error;

        if (so != ip6_mrouter)
                return EACCES;

        error = 0;

        switch (sopt->sopt_name) {
        case MRT6_PIM:
                error = sockopt_set(sopt, &pim6, sizeof(pim6));
                break;
        default:
                error = EOPNOTSUPP;
                break;
        }

        return (error);
}

/*
 * Handle ioctl commands to obtain information from the cache
 */
int
mrt6_ioctl(u_long cmd, void *data)
{

        switch (cmd) {
        case SIOCGETSGCNT_IN6:
                return (get_sg_cnt((struct sioc_sg_req6 *)data));
        case SIOCGETMIFCNT_IN6:
                return (get_mif6_cnt((struct sioc_mif_req6 *)data));
        default:
                return (EINVAL);
        }
}

/*
 * returns the packet, byte, rpf-failure count for the source group provided
 */
static int
get_sg_cnt(struct sioc_sg_req6 *req)
{
        struct mf6c *rt;
        int s;

        s = splsoftnet();
        MF6CFIND(req->src.sin6_addr, req->grp.sin6_addr, rt);
        splx(s);
        if (rt != NULL) {
                req->pktcnt = rt->mf6c_pkt_cnt;
                req->bytecnt = rt->mf6c_byte_cnt;
                req->wrong_if = rt->mf6c_wrong_if;
        } else
                return (ESRCH);
#if 0
                req->pktcnt = req->bytecnt = req->wrong_if = 0xffffffff;
#endif

        return 0;
}

/*
 * returns the input and output packet and byte counts on the mif provided
 */
static int
get_mif6_cnt(struct sioc_mif_req6 *req)
{
        mifi_t mifi = req->mifi;

        if (mifi >= nummifs)
                return EINVAL;

        req->icount = mif6table[mifi].m6_pkt_in;
        req->ocount = mif6table[mifi].m6_pkt_out;
        req->ibytes = mif6table[mifi].m6_bytes_in;
        req->obytes = mif6table[mifi].m6_bytes_out;

        return 0;
}

static int
set_pim6(int *i)
{
        if ((*i != 1) && (*i != 0))
                return EINVAL;

        pim6 = *i;

        return 0;
}

/*
 * Enable multicast routing
 */
static int
ip6_mrouter_init(struct socket *so, int v, int cmd)
{
#ifdef MRT6DEBUG
        if (mrt6debug)
                log(LOG_DEBUG,
                    "ip6_mrouter_init: so_type = %d, pr_protocol = %d\n",
                    so->so_type, so->so_proto->pr_protocol);
#endif

        if (so->so_type != SOCK_RAW ||
            so->so_proto->pr_protocol != IPPROTO_ICMPV6)
                return EOPNOTSUPP;

        if (v != 1)
                return ENOPROTOOPT;

        if (ip6_mrouter != NULL)
                return EADDRINUSE;

        ip6_mrouter = so;
        ip6_mrouter_ver = cmd;

        memset((void *)mf6ctable, 0, sizeof(mf6ctable));
        memset((void *)n6expire, 0, sizeof(n6expire));

        pim6 = 0;/* used for stubbing out/in pim stuff */

        callout_init(&expire_upcalls_ch, CALLOUT_MPSAFE);
        callout_reset(&expire_upcalls_ch, EXPIRE_TIMEOUT,
            expire_upcalls, NULL);

#ifdef MRT6DEBUG
        if (mrt6debug)
                log(LOG_DEBUG, "ip6_mrouter_init\n");
#endif

        return 0;
}

/*
 * Disable multicast routing
 */
int
ip6_mrouter_done(void)
{
        mifi_t mifi;
        int i;
        struct ifnet *ifp;
        struct sockaddr_in6 sin6;
        struct mf6c *rt;
        struct rtdetq *rte;
        int s;

        s = splsoftnet();

        /*
         * For each phyint in use, disable promiscuous reception of all IPv6
         * multicasts.
         */
#ifdef INET
#ifdef MROUTING
        /*
         * If there is still IPv4 multicast routing daemon,
         * we remain interfaces to receive all multicasted packets.
         * XXX: there may be an interface in which the IPv4 multicast
         * daemon is not interested...
         */
        if (!ip_mrouter)
#endif
#endif
        {
                for (mifi = 0; mifi < nummifs; mifi++) {
                        if (mif6table[mifi].m6_ifp &&
                            !(mif6table[mifi].m6_flags & MIFF_REGISTER)) {
                                ifp = mif6table[mifi].m6_ifp;
                                sockaddr_in6_init(&sin6, &in6addr_any, 0, 0, 0);
                                if_mcast_op(ifp, SIOCDELMULTI,
                                    sin6tocsa(&sin6));
                        }
                }
        }

        memset((void *)mif6table, 0, sizeof(mif6table));
        nummifs = 0;

        pim6 = 0; /* used to stub out/in pim specific code */

        callout_stop(&expire_upcalls_ch);

        /*
         * Free all multicast forwarding cache entries.
         */
        for (i = 0; i < MF6CTBLSIZ; i++) {
                rt = mf6ctable[i];
                while (rt) {
                        struct mf6c *frt;

                        for (rte = rt->mf6c_stall; rte != NULL; ) {
                                struct rtdetq *n = rte->next;

                                m_freem(rte->m);
                                free(rte, M_MRTABLE);
                                rte = n;
                        }
                        frt = rt;
                        rt = rt->mf6c_next;
                        free(frt, M_MRTABLE);
                }
        }

        memset((void *)mf6ctable, 0, sizeof(mf6ctable));

        /*
         * Reset register interface
         */
        if (reg_mif_num != (mifi_t)-1) {
                if_detach(&multicast_register_if6);
                reg_mif_num = (mifi_t)-1;
        }

        ip6_mrouter = NULL;
        ip6_mrouter_ver = 0;

        splx(s);

#ifdef MRT6DEBUG
        if (mrt6debug)
                log(LOG_DEBUG, "ip6_mrouter_done\n");
#endif

        return 0;
}

void
ip6_mrouter_detach(struct ifnet *ifp)
{
        struct rtdetq *rte;
        struct mf6c *mfc;
        mifi_t mifi;
        int i;

        if (ip6_mrouter == NULL)
                return;

        /*
         * Delete a mif which points to ifp.
         */
        for (mifi = 0; mifi < nummifs; mifi++)
                if (mif6table[mifi].m6_ifp == ifp)
                        del_m6if(&mifi);

        /*
         * Clear rte->ifp of cache entries received on ifp.
         */
        for (i = 0; i < MF6CTBLSIZ; i++) {
                if (n6expire[i] == 0)
                        continue;

                for (mfc = mf6ctable[i]; mfc != NULL; mfc = mfc->mf6c_next) {
                        for (rte = mfc->mf6c_stall; rte != NULL; rte = rte->next) {
                                if (rte->ifp == ifp)
                                        rte->ifp = NULL;
                        }
                }
        }
}

/*
 * Add a mif to the mif table
 */
static int
add_m6if(struct mif6ctl *mifcp)
{
        struct mif6 *mifp;
        struct ifnet *ifp;
        struct sockaddr_in6 sin6;
        int error, s;

        if (mifcp->mif6c_mifi >= MAXMIFS)
                return EINVAL;
        mifp = mif6table + mifcp->mif6c_mifi;
        if (mifp->m6_ifp)
                return EADDRINUSE; /* XXX: is it appropriate? */
        if (!mifcp->mif6c_pifi || (ifp = if_byindex(mifcp->mif6c_pifi)) == NULL)
                return ENXIO;

        if (mifcp->mif6c_flags & MIFF_REGISTER) {
                ifp = &multicast_register_if6;

                if (reg_mif_num == (mifi_t)-1) {
                        strlcpy(ifp->if_xname, "register_mif",
                            sizeof(ifp->if_xname));
                        ifp->if_flags |= IFF_LOOPBACK;
                        ifp->if_index = mifcp->mif6c_mifi;
                        reg_mif_num = mifcp->mif6c_mifi;
                        if_attach(ifp);
                }
        } else {
                /* Make sure the interface supports multicast */
                if ((ifp->if_flags & IFF_MULTICAST) == 0)
                        return EOPNOTSUPP;

                s = splsoftnet();
                /*
                 * Enable promiscuous reception of all IPv6 multicasts
                 * from the interface.
                 */
                sockaddr_in6_init(&sin6, &in6addr_any, 0, 0, 0);
                error = if_mcast_op(ifp, SIOCADDMULTI, sin6tosa(&sin6));
                splx(s);
                if (error)
                        return error;
        }

        s = splsoftnet();
        mifp->m6_flags     = mifcp->mif6c_flags;
        mifp->m6_ifp       = ifp;
        /* initialize per mif pkt counters */
        mifp->m6_pkt_in    = 0;
        mifp->m6_pkt_out   = 0;
        mifp->m6_bytes_in  = 0;
        mifp->m6_bytes_out = 0;
        splx(s);

        /* Adjust nummifs up if the mifi is higher than nummifs */
        if (nummifs <= mifcp->mif6c_mifi)
                nummifs = mifcp->mif6c_mifi + 1;

#ifdef MRT6DEBUG
        if (mrt6debug)
                log(LOG_DEBUG,
                    "add_mif #%d, phyint %s\n",
                    mifcp->mif6c_mifi, ifp->if_xname);
#endif

        return 0;
}

/*
 * Delete a mif from the mif table
 */
static int
del_m6if(mifi_t *mifip)
{
        struct mif6 *mifp = mif6table + *mifip;
        mifi_t mifi;
        struct ifnet *ifp;
        struct sockaddr_in6 sin6;
        int s;

        if (*mifip >= nummifs)
                return EINVAL;
        if (mifp->m6_ifp == NULL)
                return EINVAL;

        s = splsoftnet();

        if (!(mifp->m6_flags & MIFF_REGISTER)) {
                /*
                 * XXX: what if there is yet IPv4 multicast daemon
                 *      using the interface?
                 */
                ifp = mifp->m6_ifp;

                sockaddr_in6_init(&sin6, &in6addr_any, 0, 0, 0);
                if_mcast_op(ifp, SIOCDELMULTI, sin6tosa(&sin6));
        } else {
                if (reg_mif_num != (mifi_t)-1) {
                        if_detach(&multicast_register_if6);
                        reg_mif_num = (mifi_t)-1;
                }
        }

        memset((void *)mifp, 0, sizeof (*mifp));

        /* Adjust nummifs down */
        for (mifi = nummifs; mifi > 0; mifi--)
                if (mif6table[mifi - 1].m6_ifp)
                        break;
        nummifs = mifi;

        splx(s);

#ifdef MRT6DEBUG
        if (mrt6debug)
                log(LOG_DEBUG, "del_m6if %d, nummifs %d\n", *mifip, nummifs);
#endif

        return 0;
}

/*
 * Add an mfc entry
 */
static int
add_m6fc(struct mf6cctl *mfccp)
{
        struct mf6c *rt;
        u_long hash;
        struct rtdetq *rte;
        u_short nstl;
        int s;
        char ip6bufo[INET6_ADDRSTRLEN], ip6bufm[INET6_ADDRSTRLEN];

        MF6CFIND(mfccp->mf6cc_origin.sin6_addr,
                 mfccp->mf6cc_mcastgrp.sin6_addr, rt);

        /* If an entry already exists, just update the fields */
        if (rt) {
#ifdef MRT6DEBUG
                if (mrt6debug & DEBUG_MFC)
                        log(LOG_DEBUG,"add_m6fc update o %s g %s p %x\n",
                            IN6_PRINT(ip6bufo,
                            &mfccp->mf6cc_origin.sin6_addr),
                            IN6_PRINT(ip6bufm,
                            &mfccp->mf6cc_mcastgrp.sin6_addr),
                            mfccp->mf6cc_parent);
#endif

                s = splsoftnet();
                rt->mf6c_parent = mfccp->mf6cc_parent;
                rt->mf6c_ifset = mfccp->mf6cc_ifset;
                splx(s);
                return 0;
        }

        /*
         * Find the entry for which the upcall was made and update
         */
        s = splsoftnet();
        hash = MF6CHASH(mfccp->mf6cc_origin.sin6_addr,
                        mfccp->mf6cc_mcastgrp.sin6_addr);
        for (rt = mf6ctable[hash], nstl = 0; rt; rt = rt->mf6c_next) {
                if (IN6_ARE_ADDR_EQUAL(&rt->mf6c_origin.sin6_addr,
                                       &mfccp->mf6cc_origin.sin6_addr) &&
                    IN6_ARE_ADDR_EQUAL(&rt->mf6c_mcastgrp.sin6_addr,
                                       &mfccp->mf6cc_mcastgrp.sin6_addr) &&
                    (rt->mf6c_stall != NULL)) {

                        if (nstl++)
                                log(LOG_ERR,
                                    "add_m6fc: %s o %s g %s p %x dbx %p\n",
                                    "multiple kernel entries",
                                    IN6_PRINT(ip6bufo,
                                    &mfccp->mf6cc_origin.sin6_addr),
                                    IN6_PRINT(ip6bufm,
                                    &mfccp->mf6cc_mcastgrp.sin6_addr),
                                    mfccp->mf6cc_parent, rt->mf6c_stall);

#ifdef MRT6DEBUG
                        if (mrt6debug & DEBUG_MFC)
                                log(LOG_DEBUG,
                                    "add_m6fc o %s g %s p %x dbg %p\n",
                                    IN6_PRINT(ip6bufo,
                                    &mfccp->mf6cc_origin.sin6_addr),
                                    IN6_PRINT(ip6bufm,
                                    &mfccp->mf6cc_mcastgrp.sin6_addr),
                                    mfccp->mf6cc_parent, rt->mf6c_stall);
#endif

                        rt->mf6c_origin     = mfccp->mf6cc_origin;
                        rt->mf6c_mcastgrp   = mfccp->mf6cc_mcastgrp;
                        rt->mf6c_parent     = mfccp->mf6cc_parent;
                        rt->mf6c_ifset      = mfccp->mf6cc_ifset;
                        /* initialize pkt counters per src-grp */
                        rt->mf6c_pkt_cnt    = 0;
                        rt->mf6c_byte_cnt   = 0;
                        rt->mf6c_wrong_if   = 0;

                        rt->mf6c_expire = 0;    /* Don't clean this guy up */
                        n6expire[hash]--;

                        /* free packets Qed at the end of this entry */
                        for (rte = rt->mf6c_stall; rte != NULL; ) {
                                struct rtdetq *n = rte->next;
                                if (rte->ifp) {
                                        ip6_mdq(rte->m, rte->ifp, rt);
                                }
                                m_freem(rte->m);
#ifdef UPCALL_TIMING
                                collate(&(rte->t));
#endif
                                free(rte, M_MRTABLE);
                                rte = n;
                        }
                        rt->mf6c_stall = NULL;
                }
        }

        /*
         * It is possible that an entry is being inserted without an upcall
         */
        if (nstl == 0) {
#ifdef MRT6DEBUG
                if (mrt6debug & DEBUG_MFC)
                        log(LOG_DEBUG,
                            "add_mfc no upcall h %ld o %s g %s p %x\n",
                            hash,
                            IN6_PRINT(ip6bufo,
                            &mfccp->mf6cc_origin.sin6_addr),
                            IN6_PRINT(ip6bufm,
                            &mfccp->mf6cc_mcastgrp.sin6_addr),
                            mfccp->mf6cc_parent);
#endif

                for (rt = mf6ctable[hash]; rt; rt = rt->mf6c_next) {

                        if (IN6_ARE_ADDR_EQUAL(&rt->mf6c_origin.sin6_addr,
                                               &mfccp->mf6cc_origin.sin6_addr)&&
                            IN6_ARE_ADDR_EQUAL(&rt->mf6c_mcastgrp.sin6_addr,
                                               &mfccp->mf6cc_mcastgrp.sin6_addr)) {

                                rt->mf6c_origin     = mfccp->mf6cc_origin;
                                rt->mf6c_mcastgrp   = mfccp->mf6cc_mcastgrp;
                                rt->mf6c_parent     = mfccp->mf6cc_parent;
                                rt->mf6c_ifset      = mfccp->mf6cc_ifset;
                                /* initialize pkt counters per src-grp */
                                rt->mf6c_pkt_cnt    = 0;
                                rt->mf6c_byte_cnt   = 0;
                                rt->mf6c_wrong_if   = 0;

                                if (rt->mf6c_expire)
                                        n6expire[hash]--;
                                rt->mf6c_expire    = 0;
                        }
                }
                if (rt == NULL) {
                        /* no upcall, so make a new entry */
                        rt = malloc(sizeof(*rt), M_MRTABLE, M_NOWAIT);
                        if (rt == NULL) {
                                splx(s);
                                return ENOBUFS;
                        }

                        /* insert new entry at head of hash chain */
                        rt->mf6c_origin     = mfccp->mf6cc_origin;
                        rt->mf6c_mcastgrp   = mfccp->mf6cc_mcastgrp;
                        rt->mf6c_parent     = mfccp->mf6cc_parent;
                        rt->mf6c_ifset      = mfccp->mf6cc_ifset;
                        /* initialize pkt counters per src-grp */
                        rt->mf6c_pkt_cnt    = 0;
                        rt->mf6c_byte_cnt   = 0;
                        rt->mf6c_wrong_if   = 0;
                        rt->mf6c_expire     = 0;
                        rt->mf6c_stall = NULL;

                        /* link into table */
                        rt->mf6c_next  = mf6ctable[hash];
                        mf6ctable[hash] = rt;
                }
        }
        splx(s);
        return 0;
}

#ifdef UPCALL_TIMING
/*
 * collect delay statistics on the upcalls
 */
static void
collate(struct timeval *t)
{
        u_long d;
        struct timeval tp;
        u_long delta;

        GET_TIME(tp);

        if (TV_LT(*t, tp))
        {
                TV_DELTA(tp, *t, delta);

                d = delta >> 10;
                if (d > UPCALL_MAX)
                        d = UPCALL_MAX;

                ++upcall_data[d];
        }
}
#endif /* UPCALL_TIMING */

/*
 * Delete an mfc entry
 */
static int
del_m6fc(struct mf6cctl *mfccp)
{
        struct sockaddr_in6     origin;
        struct sockaddr_in6     mcastgrp;
        struct mf6c             *rt;
        struct mf6c             **nptr;
        u_long          hash;
        int s;

        origin = mfccp->mf6cc_origin;
        mcastgrp = mfccp->mf6cc_mcastgrp;
        hash = MF6CHASH(origin.sin6_addr, mcastgrp.sin6_addr);

#ifdef MRT6DEBUG
        if (mrt6debug & DEBUG_MFC) {
                char ip6bufo[INET6_ADDRSTRLEN], ip6bufm[INET6_ADDRSTRLEN];
                log(LOG_DEBUG,"del_m6fc orig %s mcastgrp %s\n",
                    IN6_PRINT(ip6bufo, &origin.sin6_addr),
                    IN6_PRINT(ip6bufm, &mcastgrp.sin6_addr));
        }
#endif

        s = splsoftnet();

        nptr = &mf6ctable[hash];
        while ((rt = *nptr) != NULL) {
                if (IN6_ARE_ADDR_EQUAL(&origin.sin6_addr,
                                       &rt->mf6c_origin.sin6_addr) &&
                    IN6_ARE_ADDR_EQUAL(&mcastgrp.sin6_addr,
                                       &rt->mf6c_mcastgrp.sin6_addr) &&
                    rt->mf6c_stall == NULL)
                        break;

                nptr = &rt->mf6c_next;
        }
        if (rt == NULL) {
                splx(s);
                return EADDRNOTAVAIL;
        }

        *nptr = rt->mf6c_next;
        free(rt, M_MRTABLE);

        splx(s);

        return 0;
}

static int
socket_send(struct socket *s, struct mbuf *mm, struct sockaddr_in6 *src)
{
        if (s) {
                if (sbappendaddr(&s->so_rcv, sin6tosa(src), mm, NULL) != 0) {
                        sorwakeup(s);
                        return 0;
                }
                soroverflow(s);
        }
        m_freem(mm);
        return -1;
}

/*
 * IPv6 multicast forwarding function. This function assumes that the packet
 * pointed to by "ip6" 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 IPv6 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.
 */
int
ip6_mforward(struct ip6_hdr *ip6, struct ifnet *ifp, struct mbuf *m)
{
        struct mf6c *rt;
        struct mif6 *mifp;
        struct mbuf *mm;
        int s;
        mifi_t mifi;
        struct sockaddr_in6 sin6;
        char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];

#ifdef MRT6DEBUG
        if (mrt6debug & DEBUG_FORWARD)
                log(LOG_DEBUG, "ip6_mforward: src %s, dst %s, ifindex %d\n",
                    IN6_PRINT(ip6bufs, &ip6->ip6_src),
                    IN6_PRINT(ip6bufd, &ip6->ip6_dst),
                    ifp->if_index);
#endif

        /*
         * Don't forward a packet with Hop limit of zero or one,
         * or a packet destined to a local-only group.
         */
        if (ip6->ip6_hlim <= 1 || IN6_IS_ADDR_MC_NODELOCAL(&ip6->ip6_dst) ||
            IN6_IS_ADDR_MC_LINKLOCAL(&ip6->ip6_dst))
                return 0;
        ip6->ip6_hlim--;

        /*
         * Source address check: do not forward packets with unspecified
         * source. It was discussed in July 2000, on ipngwg mailing list.
         * This is rather more serious than unicast cases, because some
         * MLD packets can be sent with the unspecified source address
         * (although such packets must normally set the hop limit field to 1).
         */
        if (IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src)) {
                IP6_STATINC(IP6_STAT_CANTFORWARD);
                if (ip6_log_time + ip6_log_interval < time_uptime) {
                        ip6_log_time = time_uptime;
                        log(LOG_DEBUG,
                            "cannot forward "
                            "from %s to %s nxt %d received on %s\n",
                            IN6_PRINT(ip6bufs, &ip6->ip6_src),
                            IN6_PRINT(ip6bufd, &ip6->ip6_dst),
                            ip6->ip6_nxt,
                            m->m_pkthdr.rcvif_index ?
                            if_name(m_get_rcvif_NOMPSAFE(m)) : "?");
                }
                return 0;
        }

        /*
         * Determine forwarding mifs from the forwarding cache table
         */
        s = splsoftnet();
        MF6CFIND(ip6->ip6_src, ip6->ip6_dst, rt);

        /* Entry exists, so forward if necessary */
        if (rt) {
                splx(s);
                return ip6_mdq(m, ifp, rt);
        } else {
                /*
                 * If we don't have a route for packet's origin, make a copy
                 * of the packet and send message to routing daemon.
                 */

                struct mbuf *mb0;
                struct rtdetq *rte;
                u_long hash;

#ifdef UPCALL_TIMING
                struct timeval tp;
                GET_TIME(tp);
#endif

                mrt6stat.mrt6s_no_route++;
#ifdef MRT6DEBUG
                if (mrt6debug & (DEBUG_FORWARD | DEBUG_MFC))
                        log(LOG_DEBUG, "ip6_mforward: no rte s %s g %s\n",
                            IN6_PRINT(ip6bufs, &ip6->ip6_src),
                            IN6_PRINT(ip6bufd, &ip6->ip6_dst));
#endif

                /*
                 * Allocate mbufs early so that we don't do extra work if we
                 * are just going to fail anyway.
                 */
                rte = malloc(sizeof(*rte), M_MRTABLE, M_NOWAIT);
                if (rte == NULL) {
                        splx(s);
                        return ENOBUFS;
                }
                mb0 = m_copypacket(m, M_DONTWAIT);

                /*
                 * Pullup packet header if needed before storing it,
                 * as other references may modify it in the meantime.
                 */
                if (mb0 && M_UNWRITABLE(mb0, sizeof(struct ip6_hdr)))
                        mb0 = m_pullup(mb0, sizeof(struct ip6_hdr));
                if (mb0 == NULL) {
                        free(rte, M_MRTABLE);
                        splx(s);
                        return ENOBUFS;
                }

                /* is there an upcall waiting for this packet? */
                hash = MF6CHASH(ip6->ip6_src, ip6->ip6_dst);
                for (rt = mf6ctable[hash]; rt; rt = rt->mf6c_next) {
                        if (IN6_ARE_ADDR_EQUAL(&ip6->ip6_src,
                                               &rt->mf6c_origin.sin6_addr) &&
                            IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst,
                                               &rt->mf6c_mcastgrp.sin6_addr) &&
                            (rt->mf6c_stall != NULL))
                                break;
                }

                if (rt == NULL) {
                        struct mrt6msg *im;
                        struct omrt6msg *oim;

                        /* no upcall, so make a new entry */
                        rt = malloc(sizeof(*rt), M_MRTABLE, M_NOWAIT);
                        if (rt == NULL) {
                                free(rte, M_MRTABLE);
                                m_freem(mb0);
                                splx(s);
                                return ENOBUFS;
                        }

                        /*
                         * Make a copy of the header to send to the user
                         * level process
                         */
                        mm = m_copym(mb0, 0, sizeof(struct ip6_hdr), M_DONTWAIT);

                        if (mm == NULL) {
                                free(rte, M_MRTABLE);
                                m_freem(mb0);
                                free(rt, M_MRTABLE);
                                splx(s);
                                return ENOBUFS;
                        }

                        /*
                         * Send message to routing daemon
                         */
                        sockaddr_in6_init(&sin6, &ip6->ip6_src, 0, 0, 0);

                        im = NULL;
                        oim = NULL;
                        switch (ip6_mrouter_ver) {
                        case MRT6_OINIT:
                                oim = mtod(mm, struct omrt6msg *);
                                oim->im6_msgtype = MRT6MSG_NOCACHE;
                                oim->im6_mbz = 0;
                                break;
                        case MRT6_INIT:
                                im = mtod(mm, struct mrt6msg *);
                                im->im6_msgtype = MRT6MSG_NOCACHE;
                                im->im6_mbz = 0;
                                break;
                        default:
                                free(rte, M_MRTABLE);
                                m_freem(mb0);
                                free(rt, M_MRTABLE);
                                splx(s);
                                return EINVAL;
                        }

#ifdef MRT6DEBUG
                        if (mrt6debug & DEBUG_FORWARD)
                                log(LOG_DEBUG,
                                    "getting the iif info in the kernel\n");
#endif

                        for (mifp = mif6table, mifi = 0;
                             mifi < nummifs && mifp->m6_ifp != ifp;
                             mifp++, mifi++)
                                ;

                        switch (ip6_mrouter_ver) {
                        case MRT6_OINIT:
                                oim->im6_mif = mifi;
                                break;
                        case MRT6_INIT:
                                im->im6_mif = mifi;
                                break;
                        }

                        if (socket_send(ip6_mrouter, mm, &sin6) < 0) {
                                log(LOG_WARNING, "ip6_mforward: ip6_mrouter "
                                    "socket queue full\n");
                                mrt6stat.mrt6s_upq_sockfull++;
                                free(rte, M_MRTABLE);
                                m_freem(mb0);
                                free(rt, M_MRTABLE);
                                splx(s);
                                return ENOBUFS;
                        }

                        mrt6stat.mrt6s_upcalls++;

                        /* insert new entry at head of hash chain */
                        memset(rt, 0, sizeof(*rt));
                        sockaddr_in6_init(&rt->mf6c_origin, &ip6->ip6_src,
                            0, 0, 0);
                        sockaddr_in6_init(&rt->mf6c_mcastgrp, &ip6->ip6_dst,
                            0, 0, 0);
                        rt->mf6c_expire = UPCALL_EXPIRE;
                        n6expire[hash]++;
                        rt->mf6c_parent = MF6C_INCOMPLETE_PARENT;

                        /* link into table */
                        rt->mf6c_next  = mf6ctable[hash];
                        mf6ctable[hash] = rt;
                        /* Add this entry to the end of the queue */
                        rt->mf6c_stall = rte;
                } else {
                        /* determine if q has overflowed */
                        struct rtdetq **p;
                        int npkts = 0;

                        for (p = &rt->mf6c_stall; *p != NULL; p = &(*p)->next) {
                                if (++npkts > MAX_UPQ6) {
                                        mrt6stat.mrt6s_upq_ovflw++;
                                        free(rte, M_MRTABLE);
                                        m_freem(mb0);
                                        splx(s);
                                        return 0;
                                }
                        }

                        /* Add this entry to the end of the queue */
                        *p = rte;
                }

                rte->next = NULL;
                rte->m = mb0;
                rte->ifp = ifp;
#ifdef UPCALL_TIMING
                rte->t = tp;
#endif

                splx(s);

                return 0;
        }
}

/*
 * Clean up cache entries if upcalls are not serviced
 * Call from the Slow Timeout mechanism, every 0.25 seconds.
 */
static void
expire_upcalls(void *unused)
{
        struct rtdetq *rte;
        struct mf6c *mfc, **nptr;
        int i;

        /* XXX NOMPSAFE still need softnet_lock */
        mutex_enter(softnet_lock);
        KERNEL_LOCK(1, NULL);

        for (i = 0; i < MF6CTBLSIZ; i++) {
                if (n6expire[i] == 0)
                        continue;
                nptr = &mf6ctable[i];
                while ((mfc = *nptr) != NULL) {
                        rte = mfc->mf6c_stall;
                        /*
                         * Skip real cache entries
                         * Make sure it wasn't marked to not expire (shouldn't happen)
                         * If it expires now
                         */
                        if (rte != NULL &&
                            mfc->mf6c_expire != 0 &&
                            --mfc->mf6c_expire == 0) {
#ifdef MRT6DEBUG
                                if (mrt6debug & DEBUG_EXPIRE) {
                                        char ip6bufo[INET6_ADDRSTRLEN];
                                        char ip6bufm[INET6_ADDRSTRLEN];
                                        log(LOG_DEBUG,
                                            "expire_upcalls: expiring (%s %s)\n",
                                            IN6_PRINT(ip6bufo,
                                            &mfc->mf6c_origin.sin6_addr),
                                            IN6_PRINT(ip6bufm,
                                            &mfc->mf6c_mcastgrp.sin6_addr));
                                }
#endif
                                /*
                                 * drop all the packets
                                 * free the mbuf with the pkt, if, timing info
                                 */
                                do {
                                        struct rtdetq *n = rte->next;
                                        m_freem(rte->m);
                                        free(rte, M_MRTABLE);
                                        rte = n;
                                } while (rte != NULL);
                                mrt6stat.mrt6s_cache_cleanups++;
                                n6expire[i]--;

                                *nptr = mfc->mf6c_next;
                                free(mfc, M_MRTABLE);
                        } else {
                                nptr = &mfc->mf6c_next;
                        }
                }
        }
        callout_reset(&expire_upcalls_ch, EXPIRE_TIMEOUT,
            expire_upcalls, NULL);

        KERNEL_UNLOCK_ONE(NULL);
        mutex_exit(softnet_lock);
}

/*
 * Macro to send packet on mif.  Since RSVP packets don't get counted on
 * input, they shouldn't get counted on output, so statistics keeping is
 * separate.
 */
#define MC6_SEND(ip6, mifp, m) do {                             \
        if ((mifp)->m6_flags & MIFF_REGISTER)                   \
                register_send((ip6), (mifp), (m));              \
        else                                                    \
                phyint_send((ip6), (mifp), (m));                \
} while (/*CONSTCOND*/ 0)

/*
 * Packet forwarding routine once entry in the cache is made
 */
static int
ip6_mdq(struct mbuf *m, struct ifnet *ifp, struct mf6c *rt)
{
        struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
        mifi_t mifi, iif;
        struct mif6 *mifp;
        int plen = m->m_pkthdr.len;
        struct in6_addr src0, dst0; /* copies for local work */
        u_int32_t iszone, idzone, oszone, odzone;
        int error = 0;

        /*
         * Don't forward if it didn't arrive from the parent mif
         * for its origin.
         */
        mifi = rt->mf6c_parent;
        if ((mifi >= nummifs) || (mif6table[mifi].m6_ifp != ifp)) {
                /* came in the wrong interface */
#ifdef MRT6DEBUG
                if (mrt6debug & DEBUG_FORWARD)
                        log(LOG_DEBUG,
                            "wrong if: ifid %d mifi %d mififid %x\n",
                            ifp->if_index, mifi,
                            mif6table[mifi].m6_ifp ?
                            mif6table[mifi].m6_ifp->if_index : -1);
#endif
                mrt6stat.mrt6s_wrong_if++;
                rt->mf6c_wrong_if++;

                /*
                 * If we are doing PIM processing, and we are forwarding
                 * packets on this interface, send a message to the
                 * routing daemon.
                 */
                /* have to make sure this is a valid mif */
                if (mifi < nummifs && mif6table[mifi].m6_ifp) {
                        if (pim6 && (m->m_flags & M_LOOP) == 0) {
                                /*
                                 * Check the M_LOOP flag to avoid an
                                 * unnecessary PIM assert.
                                 * XXX: M_LOOP is an ad-hoc hack...
                                 */
                                struct sockaddr_in6 sin6;

                                struct mbuf *mm;
                                struct mrt6msg *im;
                                struct omrt6msg *oim;

                                mm = m_copym(m, 0, sizeof(struct ip6_hdr), M_DONTWAIT);
                                if (mm && M_UNWRITABLE(mm, sizeof(struct ip6_hdr)))
                                        mm = m_pullup(mm, sizeof(struct ip6_hdr));
                                if (mm == NULL)
                                        return ENOBUFS;

                                oim = NULL;
                                im = NULL;
                                switch (ip6_mrouter_ver) {
                                case MRT6_OINIT:
                                        oim = mtod(mm, struct omrt6msg *);
                                        oim->im6_msgtype = MRT6MSG_WRONGMIF;
                                        oim->im6_mbz = 0;
                                        break;
                                case MRT6_INIT:
                                        im = mtod(mm, struct mrt6msg *);
                                        im->im6_msgtype = MRT6MSG_WRONGMIF;
                                        im->im6_mbz = 0;
                                        break;
                                default:
                                        m_freem(mm);
                                        return EINVAL;
                                }

                                for (mifp = mif6table, iif = 0;
                                     iif < nummifs && mifp &&
                                             mifp->m6_ifp != ifp;
                                     mifp++, iif++)
                                        ;

                                memset(&sin6, 0, sizeof(sin6));
                                sin6.sin6_len = sizeof(sin6);
                                sin6.sin6_family = AF_INET6;
                                switch (ip6_mrouter_ver) {
                                case MRT6_OINIT:
                                        oim->im6_mif = iif;
                                        sin6.sin6_addr = oim->im6_src;
                                        break;
                                case MRT6_INIT:
                                        im->im6_mif = iif;
                                        sin6.sin6_addr = im->im6_src;
                                        break;
                                }

                                mrt6stat.mrt6s_upcalls++;

                                if (socket_send(ip6_mrouter, mm, &sin6) < 0) {
#ifdef MRT6DEBUG
                                        if (mrt6debug)
                                                log(LOG_WARNING, "mdq, ip6_mrouter socket queue full\n");
#endif
                                        ++mrt6stat.mrt6s_upq_sockfull;
                                        return ENOBUFS;
                                }
                        }
                }

                return 0;
        }

        /* If I sourced this packet, it counts as output, else it was input. */
        if (m->m_pkthdr.rcvif_index == 0) {
                /* XXX: is rcvif really NULL when output?? */
                mif6table[mifi].m6_pkt_out++;
                mif6table[mifi].m6_bytes_out += plen;
        } else {
                mif6table[mifi].m6_pkt_in++;
                mif6table[mifi].m6_bytes_in += plen;
        }
        rt->mf6c_pkt_cnt++;
        rt->mf6c_byte_cnt += plen;

        /*
         * For each mif, forward a copy of the packet if there are group
         * members downstream on the interface.
         */
        src0 = ip6->ip6_src;
        dst0 = ip6->ip6_dst;
        if ((error = in6_setscope(&src0, ifp, &iszone)) != 0 ||
            (error = in6_setscope(&dst0, ifp, &idzone)) != 0) {
                IP6_STATINC(IP6_STAT_BADSCOPE);
                return error;
        }
        for (mifp = mif6table, mifi = 0; mifi < nummifs; mifp++, mifi++) {
                if (IF_ISSET(mifi, &rt->mf6c_ifset)) {
                        if (mif6table[mifi].m6_ifp == NULL)
                                continue;
                        /*
                         * check if the outgoing packet is going to break
                         * a scope boundary.
                         * XXX: For packets through PIM register tunnel
                         * interface, we believe the routing daemon.
                         */
                        if ((mif6table[rt->mf6c_parent].m6_flags &
                             MIFF_REGISTER) == 0 &&
                            (mif6table[mifi].m6_flags & MIFF_REGISTER) == 0) {
                                if (in6_setscope(&src0, mif6table[mifi].m6_ifp,
                                    &oszone) ||
                                    in6_setscope(&dst0, mif6table[mifi].m6_ifp,
                                    &odzone) ||
                                    iszone != oszone || idzone != odzone) {
                                        IP6_STATINC(IP6_STAT_BADSCOPE);
                                        continue;
                                }
                        }

                        mifp->m6_pkt_out++;
                        mifp->m6_bytes_out += plen;
                        MC6_SEND(ip6, mifp, m);
                }
        }

        return 0;
}

static void
phyint_send(struct ip6_hdr *ip6, struct mif6 *mifp, struct mbuf *m)
{
        struct mbuf *mb_copy;
        struct ifnet *ifp = mifp->m6_ifp;
        int error __mrt6debugused = 0;
        int s;
        static struct route ro;
        bool ingroup;
        struct sockaddr_in6 dst6;

        s = splsoftnet();

        /*
         * Make a new reference to the packet; make sure that
         * the IPv6 header is actually copied, not just referenced,
         * so that ip6_output() only scribbles on the copy.
         */
        mb_copy = m_copypacket(m, M_DONTWAIT);
        if (mb_copy && M_UNWRITABLE(mb_copy, sizeof(struct ip6_hdr)))
                mb_copy = m_pullup(mb_copy, sizeof(struct ip6_hdr));
        if (mb_copy == NULL) {
                splx(s);
                return;
        }

        /* set MCAST flag to the outgoing packet */
        mb_copy->m_flags |= M_MCAST;

        /*
         * If we sourced the packet, call ip6_output since we may divide
         * the packet into fragments when the packet is too big for the
         * outgoing interface.
         * Otherwise, we can simply send the packet to the interface
         * sending queue.
         */
        if (m->m_pkthdr.rcvif_index == 0) {
                struct ip6_moptions im6o;

                im6o.im6o_multicast_if_index = if_get_index(ifp);
                /* XXX: ip6_output will override ip6->ip6_hlim */
                im6o.im6o_multicast_hlim = ip6->ip6_hlim;
                im6o.im6o_multicast_loop = 1;
                error = ip6_output(mb_copy, NULL, &ro, IPV6_FORWARDING,
                    &im6o, NULL, NULL);

#ifdef MRT6DEBUG
                if (mrt6debug & DEBUG_XMIT)
                        log(LOG_DEBUG, "phyint_send on mif %td err %d\n",
                            mifp - mif6table, error);
#endif
                splx(s);
                return;
        }

        /*
         * If we belong to the destination multicast group
         * on the outgoing interface, loop back a copy.
         */
        /*
         * Does not have to check source info, as it's already covered by
         * ip6_input
         */
        sockaddr_in6_init(&dst6, &ip6->ip6_dst, 0, 0, 0);

        ingroup = in6_multi_group(&ip6->ip6_dst, ifp);
        if (ingroup) {
                ip6_mloopback(ifp, m,
                    satocsin6(rtcache_getdst(&ro)));
        }

        /*
         * Put the packet into the sending queue of the outgoing interface
         * if it would fit in the MTU of the interface.
         */
        if (mb_copy->m_pkthdr.len <= ifp->if_mtu || ifp->if_mtu < IPV6_MMTU) {
                error = ip6_if_output(ifp, ifp, mb_copy, &dst6, NULL);
#ifdef MRT6DEBUG
                if (mrt6debug & DEBUG_XMIT)
                        log(LOG_DEBUG, "phyint_send on mif %td err %d\n",
                            mifp - mif6table, error);
#endif
        } else {
                /*
                 * pMTU discovery is intentionally disabled by default, since
                 * various routers may notify pMTU in multicast, which can be
                 * a DDoS to a router.
                 */
                if (ip6_mcast_pmtu) {
                        icmp6_error(mb_copy, ICMP6_PACKET_TOO_BIG, 0,
                            ifp->if_mtu);
                } else {
                        /* simply discard the packet */
#ifdef MRT6DEBUG
                        if (mrt6debug & DEBUG_XMIT) {
                                char ip6bufs[INET6_ADDRSTRLEN];
                                char ip6bufd[INET6_ADDRSTRLEN];
                                log(LOG_DEBUG,
                                    "phyint_send: packet too big on %s o %s g %s"
                                    " size %d(discarded)\n",
                                    if_name(ifp),
                                    IN6_PRINT(ip6bufs, &ip6->ip6_src),
                                    IN6_PRINT(ip6bufd, &ip6->ip6_dst),
                                    mb_copy->m_pkthdr.len);
                        }
#endif
                        m_freem(mb_copy);
                }
        }

        splx(s);
}

static int
register_send(struct ip6_hdr *ip6, struct mif6 *mif, struct mbuf *m)
{
        struct mbuf *mm;
        int i, len = m->m_pkthdr.len;
        struct sockaddr_in6 sin6;
        struct mrt6msg *im6;

#ifdef MRT6DEBUG
        if (mrt6debug) {
                char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
                log(LOG_DEBUG, "** IPv6 register_send **\n src %s dst %s\n",
                    IN6_PRINT(ip6bufs, &ip6->ip6_src),
                    IN6_PRINT(ip6bufd, &ip6->ip6_dst));
        }
#endif
        PIM6_STATINC(PIM6_STAT_SND_REGISTERS);

        /* Make a copy of the packet to send to the user level process */
        MGETHDR(mm, M_DONTWAIT, MT_HEADER);
        if (mm == NULL)
                return ENOBUFS;
        mm->m_data += max_linkhdr;
        mm->m_len = sizeof(struct ip6_hdr);

        if ((mm->m_next = m_copypacket(m, M_DONTWAIT)) == NULL) {
                m_freem(mm);
                return ENOBUFS;
        }
        i = MHLEN - M_LEADINGSPACE(mm);
        if (i > len)
                i = len;
        mm = m_pullup(mm, i);
        if (mm == NULL)
                return ENOBUFS;
        mm->m_pkthdr.len = len + sizeof(struct ip6_hdr);

        /*
         * Send message to routing daemon
         */
        sockaddr_in6_init(&sin6, &ip6->ip6_src, 0, 0, 0);

        im6 = mtod(mm, struct mrt6msg *);
        im6->im6_msgtype = MRT6MSG_WHOLEPKT;
        im6->im6_mbz = 0;
        im6->im6_mif = mif - mif6table;

        /* iif info is not given for reg. encap.n */
        mrt6stat.mrt6s_upcalls++;

        if (socket_send(ip6_mrouter, mm, &sin6) < 0) {
#ifdef MRT6DEBUG
                if (mrt6debug)
                        log(LOG_WARNING,
                            "register_send: ip6_mrouter socket queue full\n");
#endif
                ++mrt6stat.mrt6s_upq_sockfull;
                return ENOBUFS;
        }

        return 0;
}

/*
 * PIM sparse mode hook. Receives the pim control messages, and passes them up
 * to the listening socket, using rip6_input.
 *
 * The only message processed is the REGISTER pim message; the pim header
 * is stripped off, and the inner packet is passed to register_mforward.
 */
int
pim6_input(struct mbuf **mp, int *offp, int proto)
{
        struct pim *pim;
        struct ip6_hdr *ip6 __mrt6debugused;
        int pimlen;
        struct mbuf *m = *mp;
        int minlen;
        int off = *offp;

        PIM6_STATINC(PIM6_STAT_RCV_TOTAL);

        ip6 = mtod(m, struct ip6_hdr *);
        pimlen = m->m_pkthdr.len - off;

        /*
         * Validate lengths
         */
        if (pimlen < PIM_MINLEN) {
                PIM6_STATINC(PIM6_STAT_RCV_TOOSHORT);
#ifdef MRT6DEBUG
                if (mrt6debug & DEBUG_PIM)
                        log(LOG_DEBUG,"pim6_input: PIM packet too short\n");
#endif
                m_freem(m);
                return IPPROTO_DONE;
        }

        /*
         * If the packet is at least as big as a REGISTER, go ahead
         * and grab the PIM REGISTER header size, to avoid another
         * possible m_pullup() later.
         *
         * PIM_MINLEN       == pimhdr + u_int32 == 8
         * PIM6_REG_MINLEN   == pimhdr + reghdr + eip6hdr == 4 + 4 + 40
         */
        minlen = (pimlen >= PIM6_REG_MINLEN) ? PIM6_REG_MINLEN : PIM_MINLEN;

        /*
         * Make sure that the IP6 and PIM headers in contiguous memory, and
         * possibly the PIM REGISTER header
         */
        IP6_EXTHDR_GET(pim, struct pim *, m, off, minlen);
        if (pim == NULL) {
                PIM6_STATINC(PIM6_STAT_RCV_TOOSHORT);
                return IPPROTO_DONE;
        }

        /* PIM version check */
        if (pim->pim_ver != PIM_VERSION) {
                PIM6_STATINC(PIM6_STAT_RCV_BADVERSION);
#ifdef MRT6DEBUG
                log(LOG_ERR,
                    "pim6_input: incorrect version %d, expecting %d\n",
                    pim->pim_ver, PIM_VERSION);
#endif
                m_freem(m);
                return IPPROTO_DONE;
        }

#define PIM6_CHECKSUM
#ifdef PIM6_CHECKSUM
        {
                int cksumlen;

                /*
                 * Validate checksum.
                 * If PIM REGISTER, exclude the data packet
                 */
                if (pim->pim_type == PIM_REGISTER)
                        cksumlen = PIM_MINLEN;
                else
                        cksumlen = pimlen;

                if (in6_cksum(m, IPPROTO_PIM, off, cksumlen)) {
                        PIM6_STATINC(PIM6_STAT_RCV_BADSUM);
#ifdef MRT6DEBUG
                        if (mrt6debug & DEBUG_PIM)
                                log(LOG_DEBUG,
                                    "pim6_input: invalid checksum\n");
#endif
                        m_freem(m);
                        return IPPROTO_DONE;
                }
        }
#endif /* PIM_CHECKSUM */

        if (pim->pim_type == PIM_REGISTER) {
                /*
                 * since this is a REGISTER, we'll make a copy of the register
                 * headers ip6+pim+u_int32_t+encap_ip6, to be passed up to the
                 * routing daemon.
                 */
                static const struct sockaddr_in6 dst = {
                        .sin6_len = sizeof(dst),
                        .sin6_family = AF_INET6,
                };

                struct mbuf *mcp;
                struct ip6_hdr *eip6;
                u_int32_t *reghdr;

                PIM6_STATINC(PIM6_STAT_RCV_REGISTERS);

                if ((reg_mif_num >= nummifs) || (reg_mif_num == (mifi_t) -1)) {
#ifdef MRT6DEBUG
                        if (mrt6debug & DEBUG_PIM)
                                log(LOG_DEBUG,
                                    "pim6_input: register mif not set: %d\n",
                                    reg_mif_num);
#endif
                        m_freem(m);
                        return IPPROTO_DONE;
                }

                reghdr = (u_int32_t *)(pim + 1);

                if ((ntohl(*reghdr) & PIM_NULL_REGISTER))
                        goto pim6_input_to_daemon;

                /*
                 * Validate length
                 */
                if (pimlen < PIM6_REG_MINLEN) {
#ifdef MRT6DEBUG
                        char ip6buf[INET6_ADDRSTRLEN];
                        log(LOG_ERR,
                            "pim6_input: register packet size too "
                            "small %d from %s\n",
                            pimlen, IN6_PRINT(ip6buf, &ip6->ip6_src));
#endif
                        PIM6_STATINC(PIM6_STAT_RCV_TOOSHORT);
                        PIM6_STATINC(PIM6_STAT_RCV_BADREGISTERS);
                        m_freem(m);
                        return IPPROTO_DONE;
                }

                eip6 = (struct ip6_hdr *)(reghdr + 1);
#ifdef MRT6DEBUG
                if (mrt6debug & DEBUG_PIM) {
                        char ip6bufs[INET6_ADDRSTRLEN];
                        char ip6bufd[INET6_ADDRSTRLEN];
                        log(LOG_DEBUG,
                            "pim6_input[register], eip6: %s -> %s, "
                            "eip6 plen %d\n",
                            IN6_PRINT(ip6bufs, &eip6->ip6_src),
                            IN6_PRINT(ip6bufd, &eip6->ip6_dst),
                            ntohs(eip6->ip6_plen));
                }
#endif

                /* verify the version number of the inner packet */
                if ((eip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) {
                        PIM6_STATINC(PIM6_STAT_RCV_BADREGISTERS);
#ifdef MRT6DEBUG
                        log(LOG_DEBUG, "pim6_input: invalid IP version (%d) "
                            "of the inner packet\n",
                            (eip6->ip6_vfc & IPV6_VERSION));
#endif
                        m_freem(m);
                        return IPPROTO_DONE;
                }

                /* verify the inner packet is destined to a mcast group */
                if (!IN6_IS_ADDR_MULTICAST(&eip6->ip6_dst)) {
                        PIM6_STATINC(PIM6_STAT_RCV_BADREGISTERS);
#ifdef MRT6DEBUG
                        if (mrt6debug & DEBUG_PIM) {
                                char ip6buf[INET6_ADDRSTRLEN];
                                log(LOG_DEBUG,
                                    "pim6_input: inner packet of register "
                                    "is not multicast %s\n",
                                    IN6_PRINT(ip6buf, &eip6->ip6_dst));
                        }
#endif
                        m_freem(m);
                        return IPPROTO_DONE;
                }

                /*
                 * make a copy of the whole header to pass to the daemon later.
                 */
                mcp = m_copym(m, 0, off + PIM6_REG_MINLEN, M_DONTWAIT);
                if (mcp == NULL) {
#ifdef MRT6DEBUG
                        log(LOG_ERR,
                            "pim6_input: pim register: "
                            "could not copy register head\n");
#endif
                        m_freem(m);
                        return IPPROTO_DONE;
                }

                /*
                 * forward the inner ip6 packet; point m_data at the inner ip6.
                 */
                m_adj(m, off + PIM_MINLEN);
#ifdef MRT6DEBUG
                if (mrt6debug & DEBUG_PIM) {
                        char ip6bufs[INET6_ADDRSTRLEN];
                        char ip6bufd[INET6_ADDRSTRLEN];
                        log(LOG_DEBUG,
                            "pim6_input: forwarding decapsulated register: "
                            "src %s, dst %s, mif %d\n",
                            IN6_PRINT(ip6bufs, &eip6->ip6_src),
                            IN6_PRINT(ip6bufd, &eip6->ip6_dst),
                            reg_mif_num);
                }
#endif

                looutput(mif6table[reg_mif_num].m6_ifp, m, sin6tocsa(&dst),
                    NULL);

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

        /*
         * 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
         * encapsulator ip6 header, pim header, register header and the
         * encapsulated ip6 header.
         */
pim6_input_to_daemon:
        /*
         * Currently, rip6_input() is always called holding softnet_lock
         * by ipintr()(!NET_MPSAFE) or PR_INPUT_WRAP()(NET_MPSAFE).
         */
        KASSERT(mutex_owned(softnet_lock));
        rip6_input(&m, offp, proto);
        return IPPROTO_DONE;
}

static int
sysctl_net_inet6_pim6_stats(SYSCTLFN_ARGS)
{

        return (NETSTAT_SYSCTL(pim6stat_percpu, PIM6_NSTATS));
}

static void
sysctl_net_inet6_pim6_setup(struct sysctllog **clog)
{

        sysctl_createv(clog, 0, NULL, NULL,
                       CTLFLAG_PERMANENT,
                       CTLTYPE_NODE, "inet6", NULL,
                       NULL, 0, NULL, 0,
                       CTL_NET, PF_INET6, CTL_EOL);
        sysctl_createv(clog, 0, NULL, NULL,
                       CTLFLAG_PERMANENT,
                       CTLTYPE_NODE, "pim6",
                       SYSCTL_DESCR("PIMv6 settings"),
                       NULL, 0, NULL, 0,
                       CTL_NET, PF_INET6, IPPROTO_PIM, CTL_EOL);

        sysctl_createv(clog, 0, NULL, NULL,
                       CTLFLAG_PERMANENT,
                       CTLTYPE_STRUCT, "stats",
                       SYSCTL_DESCR("PIMv6 statistics"),
                       sysctl_net_inet6_pim6_stats, 0, NULL, 0,
                       CTL_NET, PF_INET6, IPPROTO_PIM, PIM6CTL_STATS,
                       CTL_EOL);
}