/* $NetBSD: igmp.c,v 1.69.4.1 2020/05/18 18:59:39 martin Exp $ */ /* * Copyright (C) 1995, 1996, 1997, and 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. */ /* * Internet Group Management Protocol (IGMP) routines. * * Written by Steve Deering, Stanford, May 1988. * Modified by Rosen Sharma, Stanford, Aug 1994. * Modified by Bill Fenner, Xerox PARC, Feb 1995. * * MULTICAST Revision: 1.3 */ #include __KERNEL_RCSID(0, "$NetBSD: igmp.c,v 1.69.4.1 2020/05/18 18:59:39 martin Exp $"); #ifdef _KERNEL_OPT #include "opt_mrouting.h" #include "opt_net_mpsafe.h" #endif #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * Per-interface router version information. */ typedef struct router_info { LIST_ENTRY(router_info) rti_link; ifnet_t * rti_ifp; int rti_type; /* type of router on this interface */ int rti_age; /* time since last v1 query */ } router_info_t; /* * The router-info list and the timer flag are protected by in_multilock. * * Lock order: * * softnet_lock -> * in_multilock */ static struct pool igmp_rti_pool __cacheline_aligned; static LIST_HEAD(, router_info) rti_head __cacheline_aligned; static int igmp_timers_on __cacheline_aligned; static percpu_t * igmpstat_percpu __read_mostly; #define IGMP_STATINC(x) _NET_STATINC(igmpstat_percpu, x) static void igmp_sendpkt(struct in_multi *, int); static int rti_fill(struct in_multi *); static router_info_t * rti_find(struct ifnet *); static void rti_delete(struct ifnet *); static void sysctl_net_inet_igmp_setup(struct sysctllog **); /* * rti_fill: associate router information with the given multicast group; * if there is no router information for the interface, then create it. */ static int rti_fill(struct in_multi *inm) { router_info_t *rti; KASSERT(in_multi_lock_held()); LIST_FOREACH(rti, &rti_head, rti_link) { if (rti->rti_ifp == inm->inm_ifp) { inm->inm_rti = rti; return rti->rti_type == IGMP_v1_ROUTER ? IGMP_v1_HOST_MEMBERSHIP_REPORT : IGMP_v2_HOST_MEMBERSHIP_REPORT; } } rti = pool_get(&igmp_rti_pool, PR_NOWAIT); if (rti == NULL) { return 0; } rti->rti_ifp = inm->inm_ifp; rti->rti_type = IGMP_v2_ROUTER; LIST_INSERT_HEAD(&rti_head, rti, rti_link); inm->inm_rti = rti; return IGMP_v2_HOST_MEMBERSHIP_REPORT; } /* * rti_find: lookup or create router information for the given interface. */ static router_info_t * rti_find(ifnet_t *ifp) { router_info_t *rti; KASSERT(in_multi_lock_held()); LIST_FOREACH(rti, &rti_head, rti_link) { if (rti->rti_ifp == ifp) return rti; } rti = pool_get(&igmp_rti_pool, PR_NOWAIT); if (rti == NULL) { return NULL; } rti->rti_ifp = ifp; rti->rti_type = IGMP_v2_ROUTER; LIST_INSERT_HEAD(&rti_head, rti, rti_link); return rti; } /* * rti_delete: remove and free the router information entry for the * given interface. */ static void rti_delete(ifnet_t *ifp) { router_info_t *rti; KASSERT(in_multi_lock_held()); LIST_FOREACH(rti, &rti_head, rti_link) { if (rti->rti_ifp == ifp) { LIST_REMOVE(rti, rti_link); pool_put(&igmp_rti_pool, rti); break; } } } void igmp_init(void) { pool_init(&igmp_rti_pool, sizeof(router_info_t), 0, 0, 0, "igmppl", NULL, IPL_SOFTNET); igmpstat_percpu = percpu_alloc(sizeof(uint64_t) * IGMP_NSTATS); sysctl_net_inet_igmp_setup(NULL); LIST_INIT(&rti_head); } void igmp_input(struct mbuf *m, int off, int proto) { ifnet_t *ifp; struct ip *ip = mtod(m, struct ip *); struct igmp *igmp; u_int minlen, timer; struct in_multi *inm; struct in_ifaddr *ia; int ip_len, iphlen; struct psref psref; iphlen = off; IGMP_STATINC(IGMP_STAT_RCV_TOTAL); /* * Validate lengths */ minlen = iphlen + IGMP_MINLEN; ip_len = ntohs(ip->ip_len); if (ip_len < minlen) { IGMP_STATINC(IGMP_STAT_RCV_TOOSHORT); m_freem(m); return; } if (((m->m_flags & M_EXT) && (ip->ip_src.s_addr & IN_CLASSA_NET) == 0) || m->m_len < minlen) { if ((m = m_pullup(m, minlen)) == NULL) { IGMP_STATINC(IGMP_STAT_RCV_TOOSHORT); return; } ip = mtod(m, struct ip *); } /* * Validate checksum */ m->m_data += iphlen; m->m_len -= iphlen; igmp = mtod(m, struct igmp *); /* No need to assert alignment here. */ if (in_cksum(m, ip_len - iphlen)) { IGMP_STATINC(IGMP_STAT_RCV_BADSUM); m_freem(m); return; } m->m_data -= iphlen; m->m_len += iphlen; ifp = m_get_rcvif_psref(m, &psref); if (__predict_false(ifp == NULL)) goto drop; switch (igmp->igmp_type) { case IGMP_HOST_MEMBERSHIP_QUERY: IGMP_STATINC(IGMP_STAT_RCV_QUERIES); if (ifp->if_flags & IFF_LOOPBACK) break; if (igmp->igmp_code == 0) { struct in_multistep step; router_info_t *rti; if (ip->ip_dst.s_addr != INADDR_ALLHOSTS_GROUP) { IGMP_STATINC(IGMP_STAT_RCV_BADQUERIES); goto drop; } in_multi_lock(RW_WRITER); rti = rti_find(ifp); if (rti == NULL) { in_multi_unlock(); break; } rti->rti_type = IGMP_v1_ROUTER; rti->rti_age = 0; /* * Start the timers in all of our membership records * for the interface on which the query arrived, * except those that are already running and those * that belong to a "local" group (224.0.0.X). */ inm = in_first_multi(&step); while (inm != NULL) { if (inm->inm_ifp == ifp && inm->inm_timer == 0 && !IN_LOCAL_GROUP(inm->inm_addr.s_addr)) { inm->inm_state = IGMP_DELAYING_MEMBER; inm->inm_timer = IGMP_RANDOM_DELAY( IGMP_MAX_HOST_REPORT_DELAY * PR_FASTHZ); igmp_timers_on = true; } inm = in_next_multi(&step); } in_multi_unlock(); } else { struct in_multistep step; if (!IN_MULTICAST(ip->ip_dst.s_addr)) { IGMP_STATINC(IGMP_STAT_RCV_BADQUERIES); goto drop; } timer = igmp->igmp_code * PR_FASTHZ / IGMP_TIMER_SCALE; if (timer == 0) timer = 1; /* * Start the timers in all of our membership records * for the interface on which the query arrived, * except those that are already running and those * that belong to a "local" group (224.0.0.X). For * timers already running, check if they need to be * reset. */ in_multi_lock(RW_WRITER); inm = in_first_multi(&step); while (inm != NULL) { if (inm->inm_ifp == ifp && !IN_LOCAL_GROUP(inm->inm_addr.s_addr) && (ip->ip_dst.s_addr == INADDR_ALLHOSTS_GROUP || in_hosteq(ip->ip_dst, inm->inm_addr))) { switch (inm->inm_state) { case IGMP_DELAYING_MEMBER: if (inm->inm_timer <= timer) break; /* FALLTHROUGH */ case IGMP_IDLE_MEMBER: case IGMP_LAZY_MEMBER: case IGMP_AWAKENING_MEMBER: inm->inm_state = IGMP_DELAYING_MEMBER; inm->inm_timer = IGMP_RANDOM_DELAY(timer); igmp_timers_on = true; break; case IGMP_SLEEPING_MEMBER: inm->inm_state = IGMP_AWAKENING_MEMBER; break; } } inm = in_next_multi(&step); } in_multi_unlock(); } break; case IGMP_v1_HOST_MEMBERSHIP_REPORT: IGMP_STATINC(IGMP_STAT_RCV_REPORTS); if (ifp->if_flags & IFF_LOOPBACK) break; if (!IN_MULTICAST(igmp->igmp_group.s_addr) || !in_hosteq(igmp->igmp_group, ip->ip_dst)) { IGMP_STATINC(IGMP_STAT_RCV_BADREPORTS); goto drop; } /* * KLUDGE: if the IP source address of the report has an * unspecified (i.e., zero) subnet number, as is allowed for * a booting host, replace it with the correct subnet number * so that a process-level multicast routing daemon can * determine which subnet it arrived from. This is necessary * to compensate for the lack of any way for a process to * determine the arrival interface of an incoming packet. */ if ((ip->ip_src.s_addr & IN_CLASSA_NET) == 0) { int s = pserialize_read_enter(); ia = in_get_ia_from_ifp(ifp); /* XXX */ if (ia) ip->ip_src.s_addr = ia->ia_subnet; pserialize_read_exit(s); } /* * If we belong to the group being reported, stop * our timer for that group. */ in_multi_lock(RW_WRITER); inm = in_lookup_multi(igmp->igmp_group, ifp); if (inm != NULL) { inm->inm_timer = 0; IGMP_STATINC(IGMP_STAT_RCV_OURREPORTS); switch (inm->inm_state) { case IGMP_IDLE_MEMBER: case IGMP_LAZY_MEMBER: case IGMP_AWAKENING_MEMBER: case IGMP_SLEEPING_MEMBER: inm->inm_state = IGMP_SLEEPING_MEMBER; break; case IGMP_DELAYING_MEMBER: if (inm->inm_rti->rti_type == IGMP_v1_ROUTER) inm->inm_state = IGMP_LAZY_MEMBER; else inm->inm_state = IGMP_SLEEPING_MEMBER; break; } } in_multi_unlock(); break; case IGMP_v2_HOST_MEMBERSHIP_REPORT: { int s = pserialize_read_enter(); #ifdef MROUTING /* * Make sure we don't hear our own membership report. Fast * leave requires knowing that we are the only member of a * group. */ ia = in_get_ia_from_ifp(ifp); /* XXX */ if (ia && in_hosteq(ip->ip_src, ia->ia_addr.sin_addr)) { pserialize_read_exit(s); break; } #endif IGMP_STATINC(IGMP_STAT_RCV_REPORTS); if (ifp->if_flags & IFF_LOOPBACK) { pserialize_read_exit(s); break; } if (!IN_MULTICAST(igmp->igmp_group.s_addr) || !in_hosteq(igmp->igmp_group, ip->ip_dst)) { IGMP_STATINC(IGMP_STAT_RCV_BADREPORTS); pserialize_read_exit(s); goto drop; } /* * KLUDGE: if the IP source address of the report has an * unspecified (i.e., zero) subnet number, as is allowed for * a booting host, replace it with the correct subnet number * so that a process-level multicast routing daemon can * determine which subnet it arrived from. This is necessary * to compensate for the lack of any way for a process to * determine the arrival interface of an incoming packet. */ if ((ip->ip_src.s_addr & IN_CLASSA_NET) == 0) { #ifndef MROUTING ia = in_get_ia_from_ifp(ifp); /* XXX */ #endif if (ia) ip->ip_src.s_addr = ia->ia_subnet; } pserialize_read_exit(s); /* * If we belong to the group being reported, stop * our timer for that group. */ in_multi_lock(RW_WRITER); inm = in_lookup_multi(igmp->igmp_group, ifp); if (inm != NULL) { inm->inm_timer = 0; IGMP_STATINC(IGMP_STAT_RCV_OURREPORTS); switch (inm->inm_state) { case IGMP_DELAYING_MEMBER: case IGMP_IDLE_MEMBER: case IGMP_AWAKENING_MEMBER: inm->inm_state = IGMP_LAZY_MEMBER; break; case IGMP_LAZY_MEMBER: case IGMP_SLEEPING_MEMBER: break; } } in_multi_unlock(); break; } } m_put_rcvif_psref(ifp, &psref); /* * Pass all valid IGMP packets up to any process(es) listening * on a raw IGMP socket. */ /* * Currently, igmp_input() is always called holding softnet_lock * by ipintr()(!NET_MPSAFE) or PR_INPUT_WRAP()(NET_MPSAFE). */ KASSERT(mutex_owned(softnet_lock)); rip_input(m, iphlen, proto); return; drop: m_put_rcvif_psref(ifp, &psref); m_freem(m); return; } int igmp_joingroup(struct in_multi *inm) { KASSERT(in_multi_lock_held()); inm->inm_state = IGMP_IDLE_MEMBER; if (!IN_LOCAL_GROUP(inm->inm_addr.s_addr) && (inm->inm_ifp->if_flags & IFF_LOOPBACK) == 0) { int report_type; report_type = rti_fill(inm); if (report_type == 0) { return ENOMEM; } igmp_sendpkt(inm, report_type); inm->inm_state = IGMP_DELAYING_MEMBER; inm->inm_timer = IGMP_RANDOM_DELAY( IGMP_MAX_HOST_REPORT_DELAY * PR_FASTHZ); igmp_timers_on = true; } else inm->inm_timer = 0; return 0; } void igmp_leavegroup(struct in_multi *inm) { KASSERT(in_multi_lock_held()); switch (inm->inm_state) { case IGMP_DELAYING_MEMBER: case IGMP_IDLE_MEMBER: if (!IN_LOCAL_GROUP(inm->inm_addr.s_addr) && (inm->inm_ifp->if_flags & IFF_LOOPBACK) == 0) if (inm->inm_rti->rti_type != IGMP_v1_ROUTER) igmp_sendpkt(inm, IGMP_HOST_LEAVE_MESSAGE); break; case IGMP_LAZY_MEMBER: case IGMP_AWAKENING_MEMBER: case IGMP_SLEEPING_MEMBER: break; } } void igmp_fasttimo(void) { struct in_multi *inm; struct in_multistep step; /* * Quick check to see if any work needs to be done, in order * to minimize the overhead of fasttimo processing. */ if (!igmp_timers_on) { return; } /* XXX: Needed for ip_output(). */ SOFTNET_LOCK_UNLESS_NET_MPSAFE(); in_multi_lock(RW_WRITER); igmp_timers_on = false; inm = in_first_multi(&step); while (inm != NULL) { if (inm->inm_timer == 0) { /* do nothing */ } else if (--inm->inm_timer == 0) { if (inm->inm_state == IGMP_DELAYING_MEMBER) { if (inm->inm_rti->rti_type == IGMP_v1_ROUTER) igmp_sendpkt(inm, IGMP_v1_HOST_MEMBERSHIP_REPORT); else igmp_sendpkt(inm, IGMP_v2_HOST_MEMBERSHIP_REPORT); inm->inm_state = IGMP_IDLE_MEMBER; } } else { igmp_timers_on = true; } inm = in_next_multi(&step); } in_multi_unlock(); SOFTNET_UNLOCK_UNLESS_NET_MPSAFE(); } void igmp_slowtimo(void) { router_info_t *rti; in_multi_lock(RW_WRITER); LIST_FOREACH(rti, &rti_head, rti_link) { if (rti->rti_type == IGMP_v1_ROUTER && ++rti->rti_age >= IGMP_AGE_THRESHOLD) { rti->rti_type = IGMP_v2_ROUTER; } } in_multi_unlock(); } /* * igmp_sendpkt: construct an IGMP packet, given the multicast structure * and the type, and send the datagram. */ static void igmp_sendpkt(struct in_multi *inm, int type) { struct mbuf *m; struct igmp *igmp; struct ip *ip; struct ip_moptions imo; KASSERT(in_multi_lock_held()); MGETHDR(m, M_DONTWAIT, MT_HEADER); if (m == NULL) return; KASSERT(max_linkhdr + sizeof(struct ip) + IGMP_MINLEN <= MHLEN); m->m_data += max_linkhdr; m->m_len = sizeof(struct ip) + IGMP_MINLEN; m->m_pkthdr.len = sizeof(struct ip) + IGMP_MINLEN; ip = mtod(m, struct ip *); ip->ip_tos = 0; ip->ip_len = htons(sizeof(struct ip) + IGMP_MINLEN); ip->ip_off = htons(0); ip->ip_ttl = IP_DEFAULT_MULTICAST_TTL; ip->ip_p = IPPROTO_IGMP; ip->ip_src = zeroin_addr; ip->ip_dst = inm->inm_addr; m->m_data += sizeof(struct ip); m->m_len -= sizeof(struct ip); igmp = mtod(m, struct igmp *); igmp->igmp_type = type; igmp->igmp_code = 0; igmp->igmp_group = inm->inm_addr; igmp->igmp_cksum = 0; igmp->igmp_cksum = in_cksum(m, IGMP_MINLEN); m->m_data -= sizeof(struct ip); m->m_len += sizeof(struct ip); imo.imo_multicast_if_index = if_get_index(inm->inm_ifp); imo.imo_multicast_ttl = 1; /* * Request loopback of the report if we are acting as a multicast * router, so that the process-level routing demon can hear it. */ #ifdef MROUTING extern struct socket *ip_mrouter; imo.imo_multicast_loop = (ip_mrouter != NULL); #else imo.imo_multicast_loop = 0; #endif /* * Note: IP_IGMP_MCAST indicates that in_multilock is held. * The caller must still acquire softnet_lock for ip_output(). */ #ifndef NET_MPSAFE KASSERT(mutex_owned(softnet_lock)); #endif ip_output(m, NULL, NULL, IP_IGMP_MCAST, &imo, NULL); IGMP_STATINC(IGMP_STAT_SND_REPORTS); } void igmp_purgeif(ifnet_t *ifp) { in_multi_lock(RW_WRITER); rti_delete(ifp); in_multi_unlock(); } static int sysctl_net_inet_igmp_stats(SYSCTLFN_ARGS) { return NETSTAT_SYSCTL(igmpstat_percpu, IGMP_NSTATS); } static void sysctl_net_inet_igmp_setup(struct sysctllog **clog) { sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT, CTLTYPE_NODE, "inet", NULL, NULL, 0, NULL, 0, CTL_NET, PF_INET, CTL_EOL); sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT, CTLTYPE_NODE, "igmp", SYSCTL_DESCR("Internet Group Management Protocol"), NULL, 0, NULL, 0, CTL_NET, PF_INET, IPPROTO_IGMP, CTL_EOL); sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT, CTLTYPE_STRUCT, "stats", SYSCTL_DESCR("IGMP statistics"), sysctl_net_inet_igmp_stats, 0, NULL, 0, CTL_NET, PF_INET, IPPROTO_IGMP, CTL_CREATE, CTL_EOL); }