igmp.c revision 144163
1139823Simp/*- 21541Srgrimes * Copyright (c) 1988 Stephen Deering. 31541Srgrimes * Copyright (c) 1992, 1993 41541Srgrimes * The Regents of the University of California. All rights reserved. 51541Srgrimes * 61541Srgrimes * This code is derived from software contributed to Berkeley by 71541Srgrimes * Stephen Deering of Stanford University. 81541Srgrimes * 91541Srgrimes * Redistribution and use in source and binary forms, with or without 101541Srgrimes * modification, are permitted provided that the following conditions 111541Srgrimes * are met: 121541Srgrimes * 1. Redistributions of source code must retain the above copyright 131541Srgrimes * notice, this list of conditions and the following disclaimer. 141541Srgrimes * 2. Redistributions in binary form must reproduce the above copyright 151541Srgrimes * notice, this list of conditions and the following disclaimer in the 161541Srgrimes * documentation and/or other materials provided with the distribution. 171541Srgrimes * 4. Neither the name of the University nor the names of its contributors 181541Srgrimes * may be used to endorse or promote products derived from this software 191541Srgrimes * without specific prior written permission. 201541Srgrimes * 211541Srgrimes * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 221541Srgrimes * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 231541Srgrimes * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 241541Srgrimes * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 251541Srgrimes * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 261541Srgrimes * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 271541Srgrimes * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 281541Srgrimes * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 291541Srgrimes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 301541Srgrimes * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 311541Srgrimes * SUCH DAMAGE. 321541Srgrimes * 331541Srgrimes * @(#)igmp.c 8.1 (Berkeley) 7/19/93 3450477Speter * $FreeBSD: head/sys/netinet/igmp.c 144163 2005-03-26 22:20:22Z sam $ 351541Srgrimes */ 361541Srgrimes 372531Swollman/* 382531Swollman * Internet Group Management Protocol (IGMP) routines. 392531Swollman * 402531Swollman * Written by Steve Deering, Stanford, May 1988. 412531Swollman * Modified by Rosen Sharma, Stanford, Aug 1994. 429209Swollman * Modified by Bill Fenner, Xerox PARC, Feb 1995. 4314622Sfenner * Modified to fully comply to IGMPv2 by Bill Fenner, Oct 1995. 442531Swollman * 4514622Sfenner * MULTICAST Revision: 3.5.1.4 462531Swollman */ 471541Srgrimes 48101091Srwatson#include "opt_mac.h" 49101091Srwatson 501541Srgrimes#include <sys/param.h> 511549Srgrimes#include <sys/systm.h> 52101091Srwatson#include <sys/mac.h> 5329024Sbde#include <sys/malloc.h> 541541Srgrimes#include <sys/mbuf.h> 551541Srgrimes#include <sys/socket.h> 561541Srgrimes#include <sys/protosw.h> 5712296Sphk#include <sys/kernel.h> 586472Swollman#include <sys/sysctl.h> 591541Srgrimes 601541Srgrimes#include <net/if.h> 611541Srgrimes#include <net/route.h> 621541Srgrimes 631541Srgrimes#include <netinet/in.h> 641541Srgrimes#include <netinet/in_var.h> 651541Srgrimes#include <netinet/in_systm.h> 661541Srgrimes#include <netinet/ip.h> 671541Srgrimes#include <netinet/ip_var.h> 681541Srgrimes#include <netinet/igmp.h> 691541Srgrimes#include <netinet/igmp_var.h> 701541Srgrimes 7160105Sjlemon#include <machine/in_cksum.h> 7260105Sjlemon 7342776Sfennerstatic MALLOC_DEFINE(M_IGMP, "igmp", "igmp state"); 7430309Sphk 75119181Srwatsonstatic struct router_info *find_rti(struct ifnet *ifp); 76119181Srwatsonstatic void igmp_sendpkt(struct in_multi *, int, unsigned long); 7712579Sbde 7812704Sphkstatic struct igmpstat igmpstat; 792531Swollman 80119181SrwatsonSYSCTL_STRUCT(_net_inet_igmp, IGMPCTL_STATS, stats, CTLFLAG_RW, &igmpstat, 81119181Srwatson igmpstat, ""); 8212296Sphk 83130333Srwatson/* 84130333Srwatson * igmp_mtx protects all mutable global variables in igmp.c, as well as 85130333Srwatson * the data fields in struct router_info. In general, a router_info 86130333Srwatson * structure will be valid as long as the referencing struct in_multi is 87130333Srwatson * valid, so no reference counting is used. We allow unlocked reads of 88130333Srwatson * router_info data when accessed via an in_multi read-only. 89130333Srwatson */ 90130333Srwatsonstatic struct mtx igmp_mtx; 91119181Srwatsonstatic SLIST_HEAD(, router_info) router_info_head; 929209Swollmanstatic int igmp_timers_are_running; 93130333Srwatson 94130333Srwatson/* 95130333Srwatson * XXXRW: can we define these such that these can be made const? In any 96130333Srwatson * case, these shouldn't be changed after igmp_init() and therefore don't 97130333Srwatson * need locking. 98130333Srwatson */ 991541Srgrimesstatic u_long igmp_all_hosts_group; 10014622Sfennerstatic u_long igmp_all_rtrs_group; 101130333Srwatson 10214622Sfennerstatic struct mbuf *router_alert; 103119181Srwatsonstatic struct route igmprt; 1041541Srgrimes 105119180Srwatson#ifdef IGMP_DEBUG 106119180Srwatson#define IGMP_PRINTF(x) printf(x) 107119180Srwatson#else 108119180Srwatson#define IGMP_PRINTF(x) 109119180Srwatson#endif 110119180Srwatson 1111541Srgrimesvoid 112119181Srwatsonigmp_init(void) 1131541Srgrimes{ 11414622Sfenner struct ipoption *ra; 11514622Sfenner 1161541Srgrimes /* 1171541Srgrimes * To avoid byte-swapping the same value over and over again. 1181541Srgrimes */ 1191541Srgrimes igmp_all_hosts_group = htonl(INADDR_ALLHOSTS_GROUP); 12014622Sfenner igmp_all_rtrs_group = htonl(INADDR_ALLRTRS_GROUP); 1219209Swollman 1229209Swollman igmp_timers_are_running = 0; 1239209Swollman 12414622Sfenner /* 12514622Sfenner * Construct a Router Alert option to use in outgoing packets 12614622Sfenner */ 127111119Simp MGET(router_alert, M_DONTWAIT, MT_DATA); 12814622Sfenner ra = mtod(router_alert, struct ipoption *); 12914622Sfenner ra->ipopt_dst.s_addr = 0; 13014622Sfenner ra->ipopt_list[0] = IPOPT_RA; /* Router Alert Option */ 13114622Sfenner ra->ipopt_list[1] = 0x04; /* 4 bytes long */ 13214622Sfenner ra->ipopt_list[2] = 0x00; 13314622Sfenner ra->ipopt_list[3] = 0x00; 13414622Sfenner router_alert->m_len = sizeof(ra->ipopt_dst) + ra->ipopt_list[1]; 13514622Sfenner 136130333Srwatson mtx_init(&igmp_mtx, "igmp_mtx", NULL, MTX_DEF); 137119180Srwatson SLIST_INIT(&router_info_head); 1381541Srgrimes} 1391541Srgrimes 14012704Sphkstatic struct router_info * 141119181Srwatsonfind_rti(struct ifnet *ifp) 1422531Swollman{ 143119180Srwatson struct router_info *rti; 1442531Swollman 145130333Srwatson mtx_assert(&igmp_mtx, MA_OWNED); 146119180Srwatson IGMP_PRINTF("[igmp.c, _find_rti] --> entering \n"); 147119180Srwatson SLIST_FOREACH(rti, &router_info_head, rti_list) { 148119180Srwatson if (rti->rti_ifp == ifp) { 149119180Srwatson IGMP_PRINTF( 150119180Srwatson "[igmp.c, _find_rti] --> found old entry \n"); 151119181Srwatson return rti; 152119181Srwatson } 153119181Srwatson } 15442776Sfenner MALLOC(rti, struct router_info *, sizeof *rti, M_IGMP, M_NOWAIT); 155144163Ssam if (rti == NULL) { 156144163Ssam IGMP_PRINTF( "[igmp.c, _find_rti] --> no memory for entry\n"); 157144163Ssam return NULL; 158144163Ssam } 159119181Srwatson rti->rti_ifp = ifp; 160119181Srwatson rti->rti_type = IGMP_V2_ROUTER; 161119181Srwatson rti->rti_time = 0; 162119180Srwatson SLIST_INSERT_HEAD(&router_info_head, rti, rti_list); 163119180Srwatson 164119180Srwatson IGMP_PRINTF("[igmp.c, _find_rti] --> created an entry \n"); 165119181Srwatson return rti; 1662531Swollman} 1672531Swollman 1681541Srgrimesvoid 169119181Srwatsonigmp_input(register struct mbuf *m, int off) 1701541Srgrimes{ 171107113Sluigi register int iphlen = off; 172107113Sluigi register struct igmp *igmp; 173107113Sluigi register struct ip *ip; 174107113Sluigi register int igmplen; 175107113Sluigi register struct ifnet *ifp = m->m_pkthdr.rcvif; 176107113Sluigi register int minlen; 177107113Sluigi register struct in_multi *inm; 178107113Sluigi register struct in_ifaddr *ia; 1791541Srgrimes struct in_multistep step; 1802531Swollman struct router_info *rti; 1818546Sdg int timer; /** timer value in the igmp query header **/ 1821541Srgrimes 1831541Srgrimes ++igmpstat.igps_rcv_total; 1841541Srgrimes 1851541Srgrimes ip = mtod(m, struct ip *); 1861541Srgrimes igmplen = ip->ip_len; 1871541Srgrimes 1881541Srgrimes /* 1891541Srgrimes * Validate lengths 1901541Srgrimes */ 1911541Srgrimes if (igmplen < IGMP_MINLEN) { 1921541Srgrimes ++igmpstat.igps_rcv_tooshort; 1931541Srgrimes m_freem(m); 1941541Srgrimes return; 1951541Srgrimes } 1961541Srgrimes minlen = iphlen + IGMP_MINLEN; 1971541Srgrimes if ((m->m_flags & M_EXT || m->m_len < minlen) && 1981541Srgrimes (m = m_pullup(m, minlen)) == 0) { 1991541Srgrimes ++igmpstat.igps_rcv_tooshort; 2001541Srgrimes return; 2011541Srgrimes } 2021541Srgrimes 2031541Srgrimes /* 2041541Srgrimes * Validate checksum 2051541Srgrimes */ 2061541Srgrimes m->m_data += iphlen; 2071541Srgrimes m->m_len -= iphlen; 2081541Srgrimes igmp = mtod(m, struct igmp *); 2091541Srgrimes if (in_cksum(m, igmplen)) { 2101541Srgrimes ++igmpstat.igps_rcv_badsum; 2111541Srgrimes m_freem(m); 2121541Srgrimes return; 2131541Srgrimes } 2141541Srgrimes m->m_data -= iphlen; 2151541Srgrimes m->m_len += iphlen; 2162531Swollman 2171541Srgrimes ip = mtod(m, struct ip *); 2188546Sdg timer = igmp->igmp_code * PR_FASTHZ / IGMP_TIMER_SCALE; 21941702Sdillon if (timer == 0) 22041702Sdillon timer = 1; 2211541Srgrimes 22214622Sfenner /* 22314622Sfenner * In the IGMPv2 specification, there are 3 states and a flag. 22414622Sfenner * 22514622Sfenner * In Non-Member state, we simply don't have a membership record. 22614622Sfenner * In Delaying Member state, our timer is running (inm->inm_timer) 22714622Sfenner * In Idle Member state, our timer is not running (inm->inm_timer==0) 22814622Sfenner * 22914622Sfenner * The flag is inm->inm_state, it is set to IGMP_OTHERMEMBER if 23014622Sfenner * we have heard a report from another member, or IGMP_IREPORTEDLAST 23114622Sfenner * if I sent the last report. 23214622Sfenner */ 2331541Srgrimes switch (igmp->igmp_type) { 23414622Sfenner case IGMP_MEMBERSHIP_QUERY: 2351541Srgrimes ++igmpstat.igps_rcv_queries; 2361541Srgrimes 2378090Spst if (ifp->if_flags & IFF_LOOPBACK) 2381541Srgrimes break; 2391541Srgrimes 2402531Swollman if (igmp->igmp_code == 0) { 24114622Sfenner /* 24214622Sfenner * Old router. Remember that the querier on this 24314622Sfenner * interface is old, and set the timer to the 24414622Sfenner * value in RFC 1112. 24514622Sfenner */ 2464028Spst 247130333Srwatson mtx_lock(&igmp_mtx); 248130333Srwatson rti = find_rti(ifp); 249144163Ssam if (rti == NULL) { 250144163Ssam mtx_unlock(&igmp_mtx); 251144163Ssam m_freem(m); 252144163Ssam return; 253144163Ssam } 25414622Sfenner rti->rti_type = IGMP_V1_ROUTER; 25514622Sfenner rti->rti_time = 0; 256130333Srwatson mtx_unlock(&igmp_mtx); 2574028Spst 25814622Sfenner timer = IGMP_MAX_HOST_REPORT_DELAY * PR_FASTHZ; 2594028Spst 26014622Sfenner if (ip->ip_dst.s_addr != igmp_all_hosts_group || 26114622Sfenner igmp->igmp_group.s_addr != 0) { 2622531Swollman ++igmpstat.igps_rcv_badqueries; 2632531Swollman m_freem(m); 2642531Swollman return; 2652531Swollman } 26614622Sfenner } else { 2672531Swollman /* 26814622Sfenner * New router. Simply do the new validity check. 2692531Swollman */ 27014622Sfenner 27114622Sfenner if (igmp->igmp_group.s_addr != 0 && 27214622Sfenner !IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) { 27314622Sfenner ++igmpstat.igps_rcv_badqueries; 27414622Sfenner m_freem(m); 27514622Sfenner return; 27614622Sfenner } 27714622Sfenner } 2782531Swollman 27914622Sfenner /* 28014622Sfenner * - Start the timers in all of our membership records 28114622Sfenner * that the query applies to for the interface on 28214622Sfenner * which the query arrived excl. those that belong 28314622Sfenner * to the "all-hosts" group (224.0.0.1). 28414622Sfenner * - Restart any timer that is already running but has 28514622Sfenner * a value longer than the requested timeout. 28614622Sfenner * - Use the value specified in the query message as 28714622Sfenner * the maximum timeout. 28814622Sfenner */ 28914622Sfenner IN_FIRST_MULTI(step, inm); 29014622Sfenner while (inm != NULL) { 29114622Sfenner if (inm->inm_ifp == ifp && 29214622Sfenner inm->inm_addr.s_addr != igmp_all_hosts_group && 29314622Sfenner (igmp->igmp_group.s_addr == 0 || 29414622Sfenner igmp->igmp_group.s_addr == inm->inm_addr.s_addr)) { 29514622Sfenner if (inm->inm_timer == 0 || 29614622Sfenner inm->inm_timer > timer) { 29714622Sfenner inm->inm_timer = 29814622Sfenner IGMP_RANDOM_DELAY(timer); 2992531Swollman igmp_timers_are_running = 1; 3002531Swollman } 3011541Srgrimes } 3021541Srgrimes IN_NEXT_MULTI(step, inm); 3031541Srgrimes } 3049209Swollman 3051541Srgrimes break; 3061541Srgrimes 30714622Sfenner case IGMP_V1_MEMBERSHIP_REPORT: 30814622Sfenner case IGMP_V2_MEMBERSHIP_REPORT: 3099209Swollman /* 31014622Sfenner * For fast leave to work, we have to know that we are the 31114622Sfenner * last person to send a report for this group. Reports 31214622Sfenner * can potentially get looped back if we are a multicast 31314622Sfenner * router, so discard reports sourced by me. 3149209Swollman */ 31514622Sfenner IFP_TO_IA(ifp, ia); 31614622Sfenner if (ia && ip->ip_src.s_addr == IA_SIN(ia)->sin_addr.s_addr) 31714622Sfenner break; 31814622Sfenner 3191541Srgrimes ++igmpstat.igps_rcv_reports; 3201541Srgrimes 3218090Spst if (ifp->if_flags & IFF_LOOPBACK) 3221541Srgrimes break; 3231541Srgrimes 32414622Sfenner if (!IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) { 3251541Srgrimes ++igmpstat.igps_rcv_badreports; 3261541Srgrimes m_freem(m); 3271541Srgrimes return; 3281541Srgrimes } 3291541Srgrimes 3301541Srgrimes /* 3311541Srgrimes * KLUDGE: if the IP source address of the report has an 3321541Srgrimes * unspecified (i.e., zero) subnet number, as is allowed for 3331541Srgrimes * a booting host, replace it with the correct subnet number 33496432Sdd * so that a process-level multicast routing daemon can 3351541Srgrimes * determine which subnet it arrived from. This is necessary 3361541Srgrimes * to compensate for the lack of any way for a process to 3371541Srgrimes * determine the arrival interface of an incoming packet. 3381541Srgrimes */ 33914622Sfenner if ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) == 0) 3401541Srgrimes if (ia) ip->ip_src.s_addr = htonl(ia->ia_subnet); 3411541Srgrimes 3421541Srgrimes /* 3431541Srgrimes * If we belong to the group being reported, stop 3441541Srgrimes * our timer for that group. 3451541Srgrimes */ 3461541Srgrimes IN_LOOKUP_MULTI(igmp->igmp_group, ifp, inm); 3471541Srgrimes 3482531Swollman if (inm != NULL) { 34914622Sfenner inm->inm_timer = 0; 35014622Sfenner ++igmpstat.igps_rcv_ourreports; 35114622Sfenner 35214622Sfenner inm->inm_state = IGMP_OTHERMEMBER; 3532531Swollman } 35414622Sfenner 3551541Srgrimes break; 3561541Srgrimes } 3571541Srgrimes 3581541Srgrimes /* 3591541Srgrimes * Pass all valid IGMP packets up to any process(es) listening 3601541Srgrimes * on a raw IGMP socket. 3611541Srgrimes */ 36282890Sjulian rip_input(m, off); 3631541Srgrimes} 3641541Srgrimes 3651541Srgrimesvoid 366119181Srwatsonigmp_joingroup(struct in_multi *inm) 3671541Srgrimes{ 3689209Swollman int s = splnet(); 3691541Srgrimes 37014622Sfenner if (inm->inm_addr.s_addr == igmp_all_hosts_group 37114622Sfenner || inm->inm_ifp->if_flags & IFF_LOOPBACK) { 3721541Srgrimes inm->inm_timer = 0; 37314622Sfenner inm->inm_state = IGMP_OTHERMEMBER; 37414622Sfenner } else { 375130333Srwatson mtx_lock(&igmp_mtx); 37614622Sfenner inm->inm_rti = find_rti(inm->inm_ifp); 377130333Srwatson mtx_unlock(&igmp_mtx); 378144163Ssam if (inm->inm_rti != NULL) { 379144163Ssam igmp_sendpkt(inm, inm->inm_rti->rti_type, 0); 380144163Ssam inm->inm_timer = IGMP_RANDOM_DELAY( 3812531Swollman IGMP_MAX_HOST_REPORT_DELAY*PR_FASTHZ); 382144163Ssam inm->inm_state = IGMP_IREPORTEDLAST; 383144163Ssam igmp_timers_are_running = 1; 384144163Ssam } 385144163Ssam /* XXX handling of failure case? */ 3861541Srgrimes } 3871541Srgrimes splx(s); 3881541Srgrimes} 3891541Srgrimes 3901541Srgrimesvoid 391119181Srwatsonigmp_leavegroup(struct in_multi *inm) 3921541Srgrimes{ 393119181Srwatson 39414622Sfenner if (inm->inm_state == IGMP_IREPORTEDLAST && 39514622Sfenner inm->inm_addr.s_addr != igmp_all_hosts_group && 39614622Sfenner !(inm->inm_ifp->if_flags & IFF_LOOPBACK) && 39714622Sfenner inm->inm_rti->rti_type != IGMP_V1_ROUTER) 39814622Sfenner igmp_sendpkt(inm, IGMP_V2_LEAVE_GROUP, igmp_all_rtrs_group); 3991541Srgrimes} 4001541Srgrimes 4011541Srgrimesvoid 402119181Srwatsonigmp_fasttimo(void) 4031541Srgrimes{ 404107113Sluigi register struct in_multi *inm; 4051541Srgrimes struct in_multistep step; 4069209Swollman int s; 4071541Srgrimes 4081541Srgrimes /* 4091541Srgrimes * Quick check to see if any work needs to be done, in order 4101541Srgrimes * to minimize the overhead of fasttimo processing. 4111541Srgrimes */ 4129209Swollman 4131541Srgrimes if (!igmp_timers_are_running) 4141541Srgrimes return; 4151541Srgrimes 4161541Srgrimes s = splnet(); 4171541Srgrimes igmp_timers_are_running = 0; 4181541Srgrimes IN_FIRST_MULTI(step, inm); 4191541Srgrimes while (inm != NULL) { 4201541Srgrimes if (inm->inm_timer == 0) { 4211541Srgrimes /* do nothing */ 4221541Srgrimes } else if (--inm->inm_timer == 0) { 42314622Sfenner igmp_sendpkt(inm, inm->inm_rti->rti_type, 0); 42414622Sfenner inm->inm_state = IGMP_IREPORTEDLAST; 4251541Srgrimes } else { 4261541Srgrimes igmp_timers_are_running = 1; 4271541Srgrimes } 4281541Srgrimes IN_NEXT_MULTI(step, inm); 4291541Srgrimes } 4301541Srgrimes splx(s); 4311541Srgrimes} 4321541Srgrimes 4332531Swollmanvoid 434119181Srwatsonigmp_slowtimo(void) 4352531Swollman{ 4362531Swollman int s = splnet(); 437119180Srwatson struct router_info *rti; 4382531Swollman 439119180Srwatson IGMP_PRINTF("[igmp.c,_slowtimo] -- > entering \n"); 440130333Srwatson mtx_lock(&igmp_mtx); 441119180Srwatson SLIST_FOREACH(rti, &router_info_head, rti_list) { 442119181Srwatson if (rti->rti_type == IGMP_V1_ROUTER) { 443119181Srwatson rti->rti_time++; 444119181Srwatson if (rti->rti_time >= IGMP_AGE_THRESHOLD) 445119181Srwatson rti->rti_type = IGMP_V2_ROUTER; 4462531Swollman } 4472531Swollman } 448130333Srwatson mtx_unlock(&igmp_mtx); 449119180Srwatson IGMP_PRINTF("[igmp.c,_slowtimo] -- > exiting \n"); 4502531Swollman splx(s); 4512531Swollman} 4522531Swollman 4531541Srgrimesstatic void 454119181Srwatsonigmp_sendpkt(struct in_multi *inm, int type, unsigned long addr) 4551541Srgrimes{ 456119181Srwatson struct mbuf *m; 457119181Srwatson struct igmp *igmp; 458119181Srwatson struct ip *ip; 459119181Srwatson struct ip_moptions imo; 4601541Srgrimes 461119181Srwatson MGETHDR(m, M_DONTWAIT, MT_HEADER); 462119181Srwatson if (m == NULL) 463119181Srwatson return; 4642531Swollman 4658090Spst m->m_pkthdr.rcvif = loif; 466101091Srwatson#ifdef MAC 467101091Srwatson mac_create_mbuf_linklayer(inm->inm_ifp, m); 468101091Srwatson#endif 4691541Srgrimes m->m_pkthdr.len = sizeof(struct ip) + IGMP_MINLEN; 4702531Swollman MH_ALIGN(m, IGMP_MINLEN + sizeof(struct ip)); 4712531Swollman m->m_data += sizeof(struct ip); 472119181Srwatson m->m_len = IGMP_MINLEN; 473119181Srwatson igmp = mtod(m, struct igmp *); 474119181Srwatson igmp->igmp_type = type; 475119181Srwatson igmp->igmp_code = 0; 476119181Srwatson igmp->igmp_group = inm->inm_addr; 477119181Srwatson igmp->igmp_cksum = 0; 478119181Srwatson igmp->igmp_cksum = in_cksum(m, IGMP_MINLEN); 4791541Srgrimes 480119181Srwatson m->m_data -= sizeof(struct ip); 481119181Srwatson m->m_len += sizeof(struct ip); 482119181Srwatson ip = mtod(m, struct ip *); 483119181Srwatson ip->ip_tos = 0; 484119181Srwatson ip->ip_len = sizeof(struct ip) + IGMP_MINLEN; 485119181Srwatson ip->ip_off = 0; 486119181Srwatson ip->ip_p = IPPROTO_IGMP; 487119181Srwatson ip->ip_src.s_addr = INADDR_ANY; 488119181Srwatson ip->ip_dst.s_addr = addr ? addr : igmp->igmp_group.s_addr; 4891541Srgrimes 490119181Srwatson imo.imo_multicast_ifp = inm->inm_ifp; 491119181Srwatson imo.imo_multicast_ttl = 1; 49215292Swollman imo.imo_multicast_vif = -1; 493119181Srwatson /* 494119181Srwatson * Request loopback of the report if we are acting as a multicast 495119181Srwatson * router, so that the process-level routing daemon can hear it. 496119181Srwatson */ 497119181Srwatson imo.imo_multicast_loop = (ip_mrouter != NULL); 4981541Srgrimes 49915292Swollman /* 50015292Swollman * XXX 50115292Swollman * Do we have to worry about reentrancy here? Don't think so. 50215292Swollman */ 503119181Srwatson ip_output(m, router_alert, &igmprt, 0, &imo, NULL); 5042531Swollman 505119181Srwatson ++igmpstat.igps_snd_reports; 5061541Srgrimes} 507