/*      $FreeBSD: src/sys/netinet6/mld6.c,v 1.4.2.4 2003/01/23 21:06:47 sam Exp $       */
/*      $KAME: mld6.c,v 1.27 2001/04/04 05:17:30 itojun 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.
 */

/*
 * Copyright (c) 1988 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.
 *
 *      @(#)igmp.c      8.1 (Berkeley) 7/19/93
 */

#include "opt_inet.h"
#include "opt_inet6.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h> /* for M_NOWAIT */
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/protosw.h>
#include <sys/syslog.h>

#include <net/if.h>

#include <netinet/in.h>
#include <netinet/in_var.h>
#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
#include <netinet/icmp6.h>
#include <netinet6/mld6_var.h>

#include <net/net_osdep.h>

/*
 * Protocol constants
 */

/* denotes that the MLD max response delay field specifies time in milliseconds */
#define MLD6_TIMER_SCALE        1000
/*
 * time between repetitions of a node's initial report of interest in a
 * multicast address(in seconds)
 */
#define MLD6_UNSOLICITED_REPORT_INTERVAL        10

static struct ip6_pktopts ip6_opts;
static int mld6_timers_are_running;
/* XXX: These are necessary for KAME's link-local hack */
static struct in6_addr mld6_all_nodes_linklocal = IN6ADDR_LINKLOCAL_ALLNODES_INIT;
static struct in6_addr mld6_all_routers_linklocal = IN6ADDR_LINKLOCAL_ALLROUTERS_INIT;

static void mld6_sendpkt(struct in6_multi *, int, const struct in6_addr *);

static struct lwkt_token mld6_token = LWKT_TOKEN_INITIALIZER(mp_token);


void
mld6_init(void)
{
        static u_int8_t hbh_buf[8];
        struct ip6_hbh *hbh = (struct ip6_hbh *)hbh_buf;
        u_int16_t rtalert_code = htons((u_int16_t)IP6OPT_RTALERT_MLD);

        mld6_timers_are_running = 0;

        /* ip6h_nxt will be fill in later */
        hbh->ip6h_len = 0;      /* (8 >> 3) - 1 */

        /* XXX: grotty hard coding... */
        hbh_buf[2] = IP6OPT_PADN;       /* 2 byte padding */
        hbh_buf[3] = 0;
        hbh_buf[4] = IP6OPT_RTALERT;
        hbh_buf[5] = IP6OPT_RTALERT_LEN - 2;
        bcopy((caddr_t)&rtalert_code, &hbh_buf[6], sizeof(u_int16_t));

        init_ip6pktopts(&ip6_opts);
        ip6_opts.ip6po_hbh = hbh;
}

void
mld6_start_listening(struct in6_multi *in6m)
{
        /*
         * RFC2710 page 10:
         * The node never sends a Report or Done for the link-scope all-nodes
         * address.
         * MLD messages are never sent for multicast addresses whose scope is 0
         * (reserved) or 1 (node-local).
         */
        lwkt_gettoken(&mld6_token);
        mld6_all_nodes_linklocal.s6_addr16[1] =
                htons(in6m->in6m_ifp->if_index); /* XXX */
        if (IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr, &mld6_all_nodes_linklocal) ||
            IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) < IPV6_ADDR_SCOPE_LINKLOCAL) {
                in6m->in6m_timer = 0;
                in6m->in6m_state = MLD6_OTHERLISTENER;
        } else {
                mld6_sendpkt(in6m, MLD_LISTENER_REPORT, NULL);
                in6m->in6m_timer = MLD6_RANDOM_DELAY(
                        MLD6_UNSOLICITED_REPORT_INTERVAL * PR_FASTHZ);
                in6m->in6m_state = MLD6_IREPORTEDLAST;
                mld6_timers_are_running = 1;
        }
        lwkt_reltoken(&mld6_token);
}

void
mld6_stop_listening(struct in6_multi *in6m)
{
        mld6_all_nodes_linklocal.s6_addr16[1] =
                htons(in6m->in6m_ifp->if_index); /* XXX */
        mld6_all_routers_linklocal.s6_addr16[1] =
                htons(in6m->in6m_ifp->if_index); /* XXX: necessary when mrouting */

        if (in6m->in6m_state == MLD6_IREPORTEDLAST &&
            (!IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr, &mld6_all_nodes_linklocal)) &&
            IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) > IPV6_ADDR_SCOPE_INTFACELOCAL)
                mld6_sendpkt(in6m, MLD_LISTENER_DONE,
                             &mld6_all_routers_linklocal);
}

void
mld6_input(struct mbuf *m, int off)
{
        struct ip6_hdr *ip6;
        struct mld_hdr *mldh;
        struct ifnet *ifp = m->m_pkthdr.rcvif;
        struct in6_multi *in6m;
        struct in6_ifaddr *ia;
        struct ifmultiaddr *ifma, mark;
        struct sockaddr sa;
        int timer;              /* timer value in the MLD query header */

#ifndef PULLDOWN_TEST
        IP6_EXTHDR_CHECK(m, off, sizeof(*mldh),);
        mldh = (struct mld_hdr *)(mtod(m, caddr_t) + off);
#else
        IP6_EXTHDR_GET(mldh, struct mld_hdr *, m, off, sizeof(*mldh));
        if (mldh == NULL) {
                icmp6stat.icp6s_tooshort++;
                return;
        }
#endif

        lwkt_gettoken(&mld6_token);
        /* source address validation */
        ip6 = mtod(m, struct ip6_hdr *); /* in case mpullup */
        if (!IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_src)) {
#if 0
                log(LOG_ERR,
                    "mld6_input: src %s is not link-local (grp=%s)\n",
                    ip6_sprintf(&ip6->ip6_src),
                    ip6_sprintf(&mldh->mld_addr));
#endif
                /*
                 * spec (RFC2710) does not explicitly
                 * specify to discard the packet from a non link-local
                 * source address. But we believe it's expected to do so.
                 * XXX: do we have to allow :: as source?
                 */
                m_freem(m);
                lwkt_reltoken(&mld6_token);
                return;
        }

        /*
         * In the MLD6 specification, there are 3 states and a flag.
         *
         * In Non-Listener state, we simply don't have a membership record.
         * In Delaying Listener state, our timer is running (in6m->in6m_timer)
         * In Idle Listener state, our timer is not running (in6m->in6m_timer==0)
         *
         * The flag is in6m->in6m_state, it is set to MLD6_OTHERLISTENER if
         * we have heard a report from another member, or MLD6_IREPORTEDLAST
         * if we sent the last report.
         */
        switch(mldh->mld_type) {
        case MLD_LISTENER_QUERY:
                if (ifp->if_flags & IFF_LOOPBACK)
                        break;

                if (!IN6_IS_ADDR_UNSPECIFIED(&mldh->mld_addr) &&
                    !IN6_IS_ADDR_MULTICAST(&mldh->mld_addr))
                        break;  /* print error or log stat? */
                if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
                        mldh->mld_addr.s6_addr16[1] =
                                htons(ifp->if_index); /* XXX */

                /*
                 * - Start the timers in all of our membership records
                 *   that the query applies to for the interface on
                 *   which the query arrived excl. those that belong
                 *   to the "all-nodes" group (ff02::1).
                 * - Restart any timer that is already running but has
                 *   A value longer than the requested timeout.
                 * - Use the value specified in the query message as
                 *   the maximum timeout.
                 */
                IFP_TO_IA6(ifp, ia);
                if (ia == NULL)
                        break;

                /*
                 * XXX: System timer resolution is too low to handle Max
                 * Response Delay, so set 1 to the internal timer even if
                 * the calculated value equals to zero when Max Response
                 * Delay is positive.
                 */
                timer = ntohs(mldh->mld_maxdelay) * PR_FASTHZ /
                    MLD6_TIMER_SCALE;
                if (timer == 0 && mldh->mld_maxdelay)
                        timer = 1;
                mld6_all_nodes_linklocal.s6_addr16[1] =
                        htons(ifp->if_index); /* XXX */

                bzero(&sa, sizeof(sa));
                sa.sa_family = AF_UNSPEC;
                sa.sa_len = sizeof(sa);

                bzero(&mark, sizeof(mark));
                mark.ifma_addr = &sa;

                /* TODO: need ifnet_serialize_main */
                ifnet_serialize_all(ifp);

                TAILQ_INSERT_HEAD(&ifp->if_multiaddrs, &mark, ifma_link);
                while ((ifma = TAILQ_NEXT(&mark, ifma_link)) != NULL) {
                        TAILQ_REMOVE(&ifp->if_multiaddrs, &mark, ifma_link);
                        TAILQ_INSERT_AFTER(&ifp->if_multiaddrs, ifma, &mark,
                            ifma_link);

                        if (ifma->ifma_addr->sa_family != AF_INET6)
                                continue;
                        in6m = (struct in6_multi *)ifma->ifma_protospec;

                        if (IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr,
                                        &mld6_all_nodes_linklocal) ||
                            IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) <
                            IPV6_ADDR_SCOPE_LINKLOCAL)
                                continue;

                        if (IN6_IS_ADDR_UNSPECIFIED(&mldh->mld_addr) ||
                            IN6_ARE_ADDR_EQUAL(&mldh->mld_addr,
                                                &in6m->in6m_addr))
                        {
                                if (timer == 0) {
                                        /*
                                         * Release serializer(s) temporarily,
                                         * before sending report.
                                         */
                                        ifnet_deserialize_all(ifp);
                                        /* send a report immediately */
                                        mld6_sendpkt(in6m, MLD_LISTENER_REPORT,
                                                NULL);
                                        ifnet_serialize_all(ifp);
                                        in6m->in6m_timer = 0; /* reset timer */
                                        in6m->in6m_state = MLD6_IREPORTEDLAST;
                                }
                                else if (in6m->in6m_timer == 0 || /*idle state*/
                                        in6m->in6m_timer > timer) {
                                        in6m->in6m_timer =
                                                MLD6_RANDOM_DELAY(timer);
                                        mld6_timers_are_running = 1;
                                }
                        }
                }
                TAILQ_REMOVE(&ifp->if_multiaddrs, &mark, ifma_link);

                ifnet_deserialize_all(ifp);

                if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
                        mldh->mld_addr.s6_addr16[1] = 0; /* XXX */
                break;

        case MLD_LISTENER_REPORT:
                /*
                 * For fast leave to work, we have to know that we are the
                 * last person to send a report for this group.  Reports
                 * can potentially get looped back if we are a multicast
                 * router, so discard reports sourced by me.
                 * Note that it is impossible to check IFF_LOOPBACK flag of
                 * ifp for this purpose, since ip6_mloopback pass the physical
                 * interface to looutput.
                 */
                if (m->m_flags & M_LOOP) /* XXX: grotty flag, but efficient */
                        break;

                if (!IN6_IS_ADDR_MULTICAST(&mldh->mld_addr))
                        break;

                if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
                        mldh->mld_addr.s6_addr16[1] =
                                htons(ifp->if_index); /* XXX */
                /*
                 * If we belong to the group being reported, stop
                 * our timer for that group.
                 */
                in6m = IN6_LOOKUP_MULTI(&mldh->mld_addr, ifp);
                if (in6m) {
                        in6m->in6m_timer = 0; /* transit to idle state */
                        in6m->in6m_state = MLD6_OTHERLISTENER; /* clear flag */
                }

                if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
                        mldh->mld_addr.s6_addr16[1] = 0; /* XXX */
                break;
        default:                /* this is impossible */
                log(LOG_ERR, "mld6_input: illegal type(%d)", mldh->mld_type);
                break;
        }

        m_freem(m);
        lwkt_reltoken(&mld6_token);
}

void
mld6_fasttimeo(void)
{
        struct in6_multi *in6m;
        struct in6_multistep step;

        /*
         * Quick check to see if any work needs to be done, in order
         * to minimize the overhead of fasttimo processing.
         */
        lwkt_gettoken(&mld6_token);

        if (!mld6_timers_are_running) {
                lwkt_reltoken(&mld6_token);
                return;
        }

        mld6_timers_are_running = 0;
        IN6_FIRST_MULTI(step, in6m);
        while (in6m != NULL) {
                if (in6m->in6m_timer == 0) {
                        /* do nothing */
                } else if (--in6m->in6m_timer == 0) {
                        mld6_sendpkt(in6m, MLD_LISTENER_REPORT, NULL);
                        in6m->in6m_state = MLD6_IREPORTEDLAST;
                } else {
                        mld6_timers_are_running = 1;
                }
                IN6_NEXT_MULTI(step, in6m);
        }

        lwkt_reltoken(&mld6_token);
}

static void
mld6_sendpkt(struct in6_multi *in6m, int type, const struct in6_addr *dst)
{
        struct mbuf *mh, *md;
        struct mld_hdr *mldh;
        struct ip6_hdr *ip6;
        struct ip6_moptions im6o;
        struct in6_ifaddr *ia;
        struct ifnet *ifp = in6m->in6m_ifp;
        struct ifnet *outif = NULL;

        /*
         * At first, find a link local address on the outgoing interface
         * to use as the source address of the MLD packet.
         */
        if ((ia = in6ifa_ifpforlinklocal(ifp, IN6_IFF_NOTREADY|IN6_IFF_ANYCAST))
            == NULL)
                return;

        /*
         * Allocate mbufs to store ip6 header and MLD header.
         * We allocate 2 mbufs and make chain in advance because
         * it is more convenient when inserting the hop-by-hop option later.
         */
        MGETHDR(mh, M_NOWAIT, MT_HEADER);
        if (mh == NULL)
                return;
        MGET(md, M_NOWAIT, MT_DATA);
        if (md == NULL) {
                m_free(mh);
                return;
        }
        mh->m_next = md;

        mh->m_pkthdr.rcvif = NULL;
        mh->m_pkthdr.len = sizeof(struct ip6_hdr) + sizeof(struct mld_hdr);
        mh->m_len = sizeof(struct ip6_hdr);
        MH_ALIGN(mh, sizeof(struct ip6_hdr));

        /* fill in the ip6 header */
        ip6 = mtod(mh, struct ip6_hdr *);
        ip6->ip6_flow = 0;
        ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
        ip6->ip6_vfc |= IPV6_VERSION;
        /* ip6_plen will be set later */
        ip6->ip6_nxt = IPPROTO_ICMPV6;
        /* ip6_hlim will be set by im6o.im6o_multicast_hlim */
        ip6->ip6_src = ia->ia_addr.sin6_addr;
        ip6->ip6_dst = dst ? *dst : in6m->in6m_addr;

        /* fill in the MLD header */
        md->m_len = sizeof(struct mld_hdr);
        mldh = mtod(md, struct mld_hdr *);
        mldh->mld_type = type;
        mldh->mld_code = 0;
        mldh->mld_cksum = 0;
        /* XXX: we assume the function will not be called for query messages */
        mldh->mld_maxdelay = 0;
        mldh->mld_reserved = 0;
        mldh->mld_addr = in6m->in6m_addr;
        if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
                mldh->mld_addr.s6_addr16[1] = 0; /* XXX */
        mldh->mld_cksum = in6_cksum(mh, IPPROTO_ICMPV6, sizeof(struct ip6_hdr),
            sizeof(struct mld_hdr));

        /* construct multicast option */
        bzero(&im6o, sizeof(im6o));
        im6o.im6o_multicast_ifp = ifp;
        im6o.im6o_multicast_hlim = 1;

        /*
         * Request loopback of the report if we are acting as a multicast
         * router, so that the process-level routing daemon can hear it.
         */
        im6o.im6o_multicast_loop = (ip6_mrouter != NULL);

        /* increment output statictics */
        icmp6stat.icp6s_outhist[type]++;

        ip6_output(mh, &ip6_opts, NULL, 0, &im6o, &outif, NULL);
        if (outif) {
                icmp6_ifstat_inc(outif, ifs6_out_msg);
                switch (type) {
                case MLD_LISTENER_QUERY:
                        icmp6_ifstat_inc(outif, ifs6_out_mldquery);
                        break;
                case MLD_LISTENER_REPORT:
                        icmp6_ifstat_inc(outif, ifs6_out_mldreport);
                        break;
                case MLD_LISTENER_DONE:
                        icmp6_ifstat_inc(outif, ifs6_out_mlddone);
                        break;
                }
        }
}