/* $OpenBSD: igmp.c,v 1.16 2002/08/28 15:43:03 pefo Exp $ */ /* $NetBSD: igmp.c,v 1.15 1996/02/13 23:41:25 christos Exp $ */ /* * 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define IP_MULTICASTOPTS 0 int igmp_timers_are_running; static struct router_info *rti_head; void igmp_sendpkt(struct in_multi *, int, in_addr_t); static int rti_fill(struct in_multi *); static struct router_info * rti_find(struct ifnet *); void igmp_init() { /* * To avoid byte-swapping the same value over and over again. */ igmp_timers_are_running = 0; rti_head = 0; } /* Return -1 for error. */ static int rti_fill(inm) struct in_multi *inm; { register struct router_info *rti; for (rti = rti_head; rti != 0; rti = rti->rti_next) { if (rti->rti_ifp == inm->inm_ifp) { inm->inm_rti = rti; if (rti->rti_type == IGMP_v1_ROUTER) return (IGMP_v1_HOST_MEMBERSHIP_REPORT); else return (IGMP_v2_HOST_MEMBERSHIP_REPORT); } } rti = (struct router_info *)malloc(sizeof(struct router_info), M_MRTABLE, M_NOWAIT); if (rti == NULL) return (-1); rti->rti_ifp = inm->inm_ifp; rti->rti_type = IGMP_v2_ROUTER; rti->rti_next = rti_head; rti_head = rti; inm->inm_rti = rti; return (IGMP_v2_HOST_MEMBERSHIP_REPORT); } static struct router_info * rti_find(ifp) struct ifnet *ifp; { register struct router_info *rti; for (rti = rti_head; rti != 0; rti = rti->rti_next) { if (rti->rti_ifp == ifp) return (rti); } rti = (struct router_info *)malloc(sizeof(struct router_info), M_MRTABLE, M_NOWAIT); if (rti == NULL) return (NULL); rti->rti_ifp = ifp; rti->rti_type = IGMP_v2_ROUTER; rti->rti_next = rti_head; rti_head = rti; return (rti); } void rti_delete(ifp) struct ifnet *ifp; { struct router_info *rti, **prti = &rti_head; for (rti = rti_head; rti != 0; rti = rti->rti_next) { if (rti->rti_ifp == ifp) { *prti = rti->rti_next; free(rti, M_MRTABLE); break; } prti = &rti->rti_next; } } void igmp_input(struct mbuf *m, ...) { register int iphlen; register struct ifnet *ifp = m->m_pkthdr.rcvif; register struct ip *ip = mtod(m, struct ip *); register struct igmp *igmp; register int igmplen; register int minlen; struct in_multi *inm; struct in_multistep step; struct router_info *rti; register struct in_ifaddr *ia; int timer; va_list ap; va_start(ap, m); iphlen = va_arg(ap, int); va_end(ap); ++igmpstat.igps_rcv_total; igmplen = ip->ip_len; /* * Validate lengths */ if (igmplen < IGMP_MINLEN) { ++igmpstat.igps_rcv_tooshort; m_freem(m); return; } minlen = iphlen + IGMP_MINLEN; if ((m->m_flags & M_EXT || m->m_len < minlen) && (m = m_pullup(m, minlen)) == NULL) { ++igmpstat.igps_rcv_tooshort; return; } /* * Validate checksum */ m->m_data += iphlen; m->m_len -= iphlen; igmp = mtod(m, struct igmp *); if (in_cksum(m, igmplen)) { ++igmpstat.igps_rcv_badsum; m_freem(m); return; } m->m_data -= iphlen; m->m_len += iphlen; ip = mtod(m, struct ip *); switch (igmp->igmp_type) { case IGMP_HOST_MEMBERSHIP_QUERY: ++igmpstat.igps_rcv_queries; if (ifp->if_flags & IFF_LOOPBACK) break; if (igmp->igmp_code == 0) { rti = rti_find(ifp); if (rti == NULL) { m_freem(m); return; } rti->rti_type = IGMP_v1_ROUTER; rti->rti_age = 0; if (ip->ip_dst.s_addr != INADDR_ALLHOSTS_GROUP) { ++igmpstat.igps_rcv_badqueries; m_freem(m); return; } /* * 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). */ IN_FIRST_MULTI(step, inm); 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_are_running = 1; } IN_NEXT_MULTI(step, inm); } } else { if (!IN_MULTICAST(ip->ip_dst.s_addr)) { ++igmpstat.igps_rcv_badqueries; m_freem(m); return; } 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_FIRST_MULTI(step, inm); while (inm != NULL) { if (inm->inm_ifp == ifp && !IN_LOCAL_GROUP(inm->inm_addr.s_addr) && (ip->ip_dst.s_addr == INADDR_ALLHOSTS_GROUP || ip->ip_dst.s_addr == inm->inm_addr.s_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_are_running = 1; break; case IGMP_SLEEPING_MEMBER: inm->inm_state = IGMP_AWAKENING_MEMBER; break; } } IN_NEXT_MULTI(step, inm); } } break; case IGMP_v1_HOST_MEMBERSHIP_REPORT: ++igmpstat.igps_rcv_reports; if (ifp->if_flags & IFF_LOOPBACK) break; if (!IN_MULTICAST(igmp->igmp_group.s_addr) || igmp->igmp_group.s_addr != ip->ip_dst.s_addr) { ++igmpstat.igps_rcv_badreports; m_freem(m); return; } /* * 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) { IFP_TO_IA(ifp, ia); if (ia) ip->ip_src.s_addr = ia->ia_subnet; } /* * If we belong to the group being reported, stop * our timer for that group. */ IN_LOOKUP_MULTI(igmp->igmp_group, ifp, inm); if (inm != NULL) { inm->inm_timer = 0; ++igmpstat.igps_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; } } break; case IGMP_v2_HOST_MEMBERSHIP_REPORT: #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. */ IFP_TO_IA(ifp, ia); if (ia && ip->ip_src.s_addr == ia->ia_addr.sin_addr.s_addr) break; #endif ++igmpstat.igps_rcv_reports; if (ifp->if_flags & IFF_LOOPBACK) break; if (!IN_MULTICAST(igmp->igmp_group.s_addr) || igmp->igmp_group.s_addr != ip->ip_dst.s_addr) { ++igmpstat.igps_rcv_badreports; m_freem(m); return; } /* * 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 IFP_TO_IA(ifp, ia); #endif if (ia) ip->ip_src.s_addr = ia->ia_subnet; } /* * If we belong to the group being reported, stop * our timer for that group. */ IN_LOOKUP_MULTI(igmp->igmp_group, ifp, inm); if (inm != NULL) { inm->inm_timer = 0; ++igmpstat.igps_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; } } break; } /* * Pass all valid IGMP packets up to any process(es) listening * on a raw IGMP socket. */ rip_input(m); } void igmp_joingroup(inm) struct in_multi *inm; { int i, s = splsoftnet(); inm->inm_state = IGMP_IDLE_MEMBER; if (!IN_LOCAL_GROUP(inm->inm_addr.s_addr) && (inm->inm_ifp->if_flags & IFF_LOOPBACK) == 0) { if ((i = rti_fill(inm)) == -1) return; igmp_sendpkt(inm, i, 0); inm->inm_state = IGMP_DELAYING_MEMBER; inm->inm_timer = IGMP_RANDOM_DELAY( IGMP_MAX_HOST_REPORT_DELAY * PR_FASTHZ); igmp_timers_are_running = 1; } else inm->inm_timer = 0; splx(s); } void igmp_leavegroup(inm) struct in_multi *inm; { 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, INADDR_ALLROUTERS_GROUP); break; case IGMP_LAZY_MEMBER: case IGMP_AWAKENING_MEMBER: case IGMP_SLEEPING_MEMBER: break; } } void igmp_fasttimo() { register struct in_multi *inm; struct in_multistep step; int s; /* * Quick check to see if any work needs to be done, in order * to minimize the overhead of fasttimo processing. */ if (!igmp_timers_are_running) return; s = splsoftnet(); igmp_timers_are_running = 0; IN_FIRST_MULTI(step, inm); 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, 0); else igmp_sendpkt(inm, IGMP_v2_HOST_MEMBERSHIP_REPORT, 0); inm->inm_state = IGMP_IDLE_MEMBER; } } else { igmp_timers_are_running = 1; } IN_NEXT_MULTI(step, inm); } splx(s); } void igmp_slowtimo() { register struct router_info *rti; int s; s = splsoftnet(); for (rti = rti_head; rti != 0; rti = rti->rti_next) { if (rti->rti_type == IGMP_v1_ROUTER && ++rti->rti_age >= IGMP_AGE_THRESHOLD) { rti->rti_type = IGMP_v2_ROUTER; } } splx(s); } void igmp_sendpkt(inm, type, addr) struct in_multi *inm; int type; in_addr_t addr; { struct mbuf *m; struct igmp *igmp; struct ip *ip; struct ip_moptions imo; #ifdef MROUTING extern struct socket *ip_mrouter; #endif /* MROUTING */ MGETHDR(m, M_DONTWAIT, MT_HEADER); if (m == NULL) return; /* * Assume max_linkhdr + sizeof(struct ip) + IGMP_MINLEN * is smaller than mbuf size returned by MGETHDR. */ 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 = sizeof(struct ip) + IGMP_MINLEN; ip->ip_off = 0; ip->ip_p = IPPROTO_IGMP; ip->ip_src.s_addr = INADDR_ANY; if (addr) { ip->ip_dst.s_addr = addr; } else { 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_ifp = inm->inm_ifp; imo.imo_multicast_ttl = 1; #ifdef RSVP_ISI imo.imo_multicast_vif = -1; #endif /* * 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 imo.imo_multicast_loop = (ip_mrouter != NULL); #else imo.imo_multicast_loop = 0; #endif /* MROUTING */ ip_output(m, (struct mbuf *)0, (struct route *)0, IP_MULTICASTOPTS, &imo, (void *)NULL); ++igmpstat.igps_snd_reports; }