/* * 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. * 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. * * @(#)igmp.c 8.1 (Berkeley) 7/19/93 * $FreeBSD$ */ /* * 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. * Modified to fully comply to IGMPv2 by Bill Fenner, Oct 1995. * * MULTICAST Revision: 3.5.1.4 */ #include "opt_mac.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include static MALLOC_DEFINE(M_IGMP, "igmp", "igmp state"); static struct router_info *find_rti(struct ifnet *ifp); static void igmp_sendpkt(struct in_multi *, int, unsigned long); static struct igmpstat igmpstat; SYSCTL_STRUCT(_net_inet_igmp, IGMPCTL_STATS, stats, CTLFLAG_RW, &igmpstat, igmpstat, ""); /* * igmp_mtx protects all mutable global variables in igmp.c, as well as * the data fields in struct router_info. In general, a router_info * structure will be valid as long as the referencing struct in_multi is * valid, so no reference counting is used. We allow unlocked reads of * router_info data when accessed via an in_multi read-only. */ static struct mtx igmp_mtx; static SLIST_HEAD(, router_info) router_info_head; static int igmp_timers_are_running; /* * XXXRW: can we define these such that these can be made const? In any * case, these shouldn't be changed after igmp_init() and therefore don't * need locking. */ static u_long igmp_all_hosts_group; static u_long igmp_all_rtrs_group; static struct mbuf *router_alert; static struct route igmprt; #ifdef IGMP_DEBUG #define IGMP_PRINTF(x) printf(x) #else #define IGMP_PRINTF(x) #endif void igmp_init(void) { struct ipoption *ra; /* * To avoid byte-swapping the same value over and over again. */ igmp_all_hosts_group = htonl(INADDR_ALLHOSTS_GROUP); igmp_all_rtrs_group = htonl(INADDR_ALLRTRS_GROUP); igmp_timers_are_running = 0; /* * Construct a Router Alert option to use in outgoing packets */ MGET(router_alert, M_DONTWAIT, MT_DATA); ra = mtod(router_alert, struct ipoption *); ra->ipopt_dst.s_addr = 0; ra->ipopt_list[0] = IPOPT_RA; /* Router Alert Option */ ra->ipopt_list[1] = 0x04; /* 4 bytes long */ ra->ipopt_list[2] = 0x00; ra->ipopt_list[3] = 0x00; router_alert->m_len = sizeof(ra->ipopt_dst) + ra->ipopt_list[1]; mtx_init(&igmp_mtx, "igmp_mtx", NULL, MTX_DEF); SLIST_INIT(&router_info_head); } static struct router_info * find_rti(struct ifnet *ifp) { struct router_info *rti; mtx_assert(&igmp_mtx, MA_OWNED); IGMP_PRINTF("[igmp.c, _find_rti] --> entering \n"); SLIST_FOREACH(rti, &router_info_head, rti_list) { if (rti->rti_ifp == ifp) { IGMP_PRINTF( "[igmp.c, _find_rti] --> found old entry \n"); return rti; } } /* * XXXRW: return value of malloc not checked, despite M_NOWAIT. */ MALLOC(rti, struct router_info *, sizeof *rti, M_IGMP, M_NOWAIT); rti->rti_ifp = ifp; rti->rti_type = IGMP_V2_ROUTER; rti->rti_time = 0; SLIST_INSERT_HEAD(&router_info_head, rti, rti_list); IGMP_PRINTF("[igmp.c, _find_rti] --> created an entry \n"); return rti; } void igmp_input(register struct mbuf *m, int off) { register int iphlen = off; register struct igmp *igmp; register struct ip *ip; register int igmplen; register struct ifnet *ifp = m->m_pkthdr.rcvif; register int minlen; register struct in_multi *inm; register struct in_ifaddr *ia; struct in_multistep step; struct router_info *rti; int timer; /** timer value in the igmp query header **/ ++igmpstat.igps_rcv_total; ip = mtod(m, struct ip *); 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)) == 0) { ++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 *); timer = igmp->igmp_code * PR_FASTHZ / IGMP_TIMER_SCALE; if (timer == 0) timer = 1; /* * In the IGMPv2 specification, there are 3 states and a flag. * * In Non-Member state, we simply don't have a membership record. * In Delaying Member state, our timer is running (inm->inm_timer) * In Idle Member state, our timer is not running (inm->inm_timer==0) * * The flag is inm->inm_state, it is set to IGMP_OTHERMEMBER if * we have heard a report from another member, or IGMP_IREPORTEDLAST * if I sent the last report. */ switch (igmp->igmp_type) { case IGMP_MEMBERSHIP_QUERY: ++igmpstat.igps_rcv_queries; if (ifp->if_flags & IFF_LOOPBACK) break; if (igmp->igmp_code == 0) { /* * Old router. Remember that the querier on this * interface is old, and set the timer to the * value in RFC 1112. */ mtx_lock(&igmp_mtx); rti = find_rti(ifp); rti->rti_type = IGMP_V1_ROUTER; rti->rti_time = 0; mtx_unlock(&igmp_mtx); timer = IGMP_MAX_HOST_REPORT_DELAY * PR_FASTHZ; if (ip->ip_dst.s_addr != igmp_all_hosts_group || igmp->igmp_group.s_addr != 0) { ++igmpstat.igps_rcv_badqueries; m_freem(m); return; } } else { /* * New router. Simply do the new validity check. */ if (igmp->igmp_group.s_addr != 0 && !IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) { ++igmpstat.igps_rcv_badqueries; m_freem(m); return; } } /* * - 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-hosts" group (224.0.0.1). * - 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. */ IN_FIRST_MULTI(step, inm); while (inm != NULL) { if (inm->inm_ifp == ifp && inm->inm_addr.s_addr != igmp_all_hosts_group && (igmp->igmp_group.s_addr == 0 || igmp->igmp_group.s_addr == inm->inm_addr.s_addr)) { if (inm->inm_timer == 0 || inm->inm_timer > timer) { inm->inm_timer = IGMP_RANDOM_DELAY(timer); igmp_timers_are_running = 1; } } IN_NEXT_MULTI(step, inm); } break; case IGMP_V1_MEMBERSHIP_REPORT: case IGMP_V2_MEMBERSHIP_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. */ IFP_TO_IA(ifp, ia); if (ia && ip->ip_src.s_addr == IA_SIN(ia)->sin_addr.s_addr) break; ++igmpstat.igps_rcv_reports; if (ifp->if_flags & IFF_LOOPBACK) break; if (!IN_MULTICAST(ntohl(igmp->igmp_group.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 ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) == 0) if (ia) ip->ip_src.s_addr = htonl(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; inm->inm_state = IGMP_OTHERMEMBER; } break; } /* * Pass all valid IGMP packets up to any process(es) listening * on a raw IGMP socket. */ rip_input(m, off); } void igmp_joingroup(struct in_multi *inm) { int s = splnet(); if (inm->inm_addr.s_addr == igmp_all_hosts_group || inm->inm_ifp->if_flags & IFF_LOOPBACK) { inm->inm_timer = 0; inm->inm_state = IGMP_OTHERMEMBER; } else { mtx_lock(&igmp_mtx); inm->inm_rti = find_rti(inm->inm_ifp); mtx_unlock(&igmp_mtx); igmp_sendpkt(inm, inm->inm_rti->rti_type, 0); inm->inm_timer = IGMP_RANDOM_DELAY( IGMP_MAX_HOST_REPORT_DELAY*PR_FASTHZ); inm->inm_state = IGMP_IREPORTEDLAST; igmp_timers_are_running = 1; } splx(s); } void igmp_leavegroup(struct in_multi *inm) { if (inm->inm_state == IGMP_IREPORTEDLAST && inm->inm_addr.s_addr != igmp_all_hosts_group && !(inm->inm_ifp->if_flags & IFF_LOOPBACK) && inm->inm_rti->rti_type != IGMP_V1_ROUTER) igmp_sendpkt(inm, IGMP_V2_LEAVE_GROUP, igmp_all_rtrs_group); } void igmp_fasttimo(void) { 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 = splnet(); 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) { igmp_sendpkt(inm, inm->inm_rti->rti_type, 0); inm->inm_state = IGMP_IREPORTEDLAST; } else { igmp_timers_are_running = 1; } IN_NEXT_MULTI(step, inm); } splx(s); } void igmp_slowtimo(void) { int s = splnet(); struct router_info *rti; IGMP_PRINTF("[igmp.c,_slowtimo] -- > entering \n"); mtx_lock(&igmp_mtx); SLIST_FOREACH(rti, &router_info_head, rti_list) { if (rti->rti_type == IGMP_V1_ROUTER) { rti->rti_time++; if (rti->rti_time >= IGMP_AGE_THRESHOLD) rti->rti_type = IGMP_V2_ROUTER; } } mtx_unlock(&igmp_mtx); IGMP_PRINTF("[igmp.c,_slowtimo] -- > exiting \n"); splx(s); } static void igmp_sendpkt(struct in_multi *inm, int type, unsigned long addr) { struct mbuf *m; struct igmp *igmp; struct ip *ip; struct ip_moptions imo; MGETHDR(m, M_DONTWAIT, MT_HEADER); if (m == NULL) return; m->m_pkthdr.rcvif = loif; #ifdef MAC mac_create_mbuf_linklayer(inm->inm_ifp, m); #endif m->m_pkthdr.len = sizeof(struct ip) + IGMP_MINLEN; MH_ALIGN(m, IGMP_MINLEN + sizeof(struct ip)); m->m_data += sizeof(struct ip); m->m_len = IGMP_MINLEN; 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); 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; ip->ip_dst.s_addr = addr ? addr : igmp->igmp_group.s_addr; imo.imo_multicast_ifp = inm->inm_ifp; imo.imo_multicast_ttl = 1; imo.imo_multicast_vif = -1; /* * Request loopback of the report if we are acting as a multicast * router, so that the process-level routing daemon can hear it. */ imo.imo_multicast_loop = (ip_mrouter != NULL); /* * XXX * Do we have to worry about reentrancy here? Don't think so. */ ip_output(m, router_alert, &igmprt, 0, &imo, NULL); ++igmpstat.igps_snd_reports; }