igmp.c revision 130333
11541Srgrimes/* 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 130333 2004-06-11 03:42:37Z rwatson $ 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 } 154130333Srwatson /* 155130333Srwatson * XXXRW: return value of malloc not checked, despite M_NOWAIT. 156130333Srwatson */ 15742776Sfenner MALLOC(rti, struct router_info *, sizeof *rti, M_IGMP, M_NOWAIT); 158119181Srwatson rti->rti_ifp = ifp; 159119181Srwatson rti->rti_type = IGMP_V2_ROUTER; 160119181Srwatson rti->rti_time = 0; 161119180Srwatson SLIST_INSERT_HEAD(&router_info_head, rti, rti_list); 162119180Srwatson 163119180Srwatson IGMP_PRINTF("[igmp.c, _find_rti] --> created an entry \n"); 164119181Srwatson return rti; 1652531Swollman} 1662531Swollman 1671541Srgrimesvoid 168119181Srwatsonigmp_input(register struct mbuf *m, int off) 1691541Srgrimes{ 170107113Sluigi register int iphlen = off; 171107113Sluigi register struct igmp *igmp; 172107113Sluigi register struct ip *ip; 173107113Sluigi register int igmplen; 174107113Sluigi register struct ifnet *ifp = m->m_pkthdr.rcvif; 175107113Sluigi register int minlen; 176107113Sluigi register struct in_multi *inm; 177107113Sluigi register struct in_ifaddr *ia; 1781541Srgrimes struct in_multistep step; 1792531Swollman struct router_info *rti; 1808546Sdg int timer; /** timer value in the igmp query header **/ 1811541Srgrimes 1821541Srgrimes ++igmpstat.igps_rcv_total; 1831541Srgrimes 1841541Srgrimes ip = mtod(m, struct ip *); 1851541Srgrimes igmplen = ip->ip_len; 1861541Srgrimes 1871541Srgrimes /* 1881541Srgrimes * Validate lengths 1891541Srgrimes */ 1901541Srgrimes if (igmplen < IGMP_MINLEN) { 1911541Srgrimes ++igmpstat.igps_rcv_tooshort; 1921541Srgrimes m_freem(m); 1931541Srgrimes return; 1941541Srgrimes } 1951541Srgrimes minlen = iphlen + IGMP_MINLEN; 1961541Srgrimes if ((m->m_flags & M_EXT || m->m_len < minlen) && 1971541Srgrimes (m = m_pullup(m, minlen)) == 0) { 1981541Srgrimes ++igmpstat.igps_rcv_tooshort; 1991541Srgrimes return; 2001541Srgrimes } 2011541Srgrimes 2021541Srgrimes /* 2031541Srgrimes * Validate checksum 2041541Srgrimes */ 2051541Srgrimes m->m_data += iphlen; 2061541Srgrimes m->m_len -= iphlen; 2071541Srgrimes igmp = mtod(m, struct igmp *); 2081541Srgrimes if (in_cksum(m, igmplen)) { 2091541Srgrimes ++igmpstat.igps_rcv_badsum; 2101541Srgrimes m_freem(m); 2111541Srgrimes return; 2121541Srgrimes } 2131541Srgrimes m->m_data -= iphlen; 2141541Srgrimes m->m_len += iphlen; 2152531Swollman 2161541Srgrimes ip = mtod(m, struct ip *); 2178546Sdg timer = igmp->igmp_code * PR_FASTHZ / IGMP_TIMER_SCALE; 21841702Sdillon if (timer == 0) 21941702Sdillon timer = 1; 2201541Srgrimes 22114622Sfenner /* 22214622Sfenner * In the IGMPv2 specification, there are 3 states and a flag. 22314622Sfenner * 22414622Sfenner * In Non-Member state, we simply don't have a membership record. 22514622Sfenner * In Delaying Member state, our timer is running (inm->inm_timer) 22614622Sfenner * In Idle Member state, our timer is not running (inm->inm_timer==0) 22714622Sfenner * 22814622Sfenner * The flag is inm->inm_state, it is set to IGMP_OTHERMEMBER if 22914622Sfenner * we have heard a report from another member, or IGMP_IREPORTEDLAST 23014622Sfenner * if I sent the last report. 23114622Sfenner */ 2321541Srgrimes switch (igmp->igmp_type) { 23314622Sfenner case IGMP_MEMBERSHIP_QUERY: 2341541Srgrimes ++igmpstat.igps_rcv_queries; 2351541Srgrimes 2368090Spst if (ifp->if_flags & IFF_LOOPBACK) 2371541Srgrimes break; 2381541Srgrimes 2392531Swollman if (igmp->igmp_code == 0) { 24014622Sfenner /* 24114622Sfenner * Old router. Remember that the querier on this 24214622Sfenner * interface is old, and set the timer to the 24314622Sfenner * value in RFC 1112. 24414622Sfenner */ 2454028Spst 246130333Srwatson mtx_lock(&igmp_mtx); 247130333Srwatson rti = find_rti(ifp); 24814622Sfenner rti->rti_type = IGMP_V1_ROUTER; 24914622Sfenner rti->rti_time = 0; 250130333Srwatson mtx_unlock(&igmp_mtx); 2514028Spst 25214622Sfenner timer = IGMP_MAX_HOST_REPORT_DELAY * PR_FASTHZ; 2534028Spst 25414622Sfenner if (ip->ip_dst.s_addr != igmp_all_hosts_group || 25514622Sfenner igmp->igmp_group.s_addr != 0) { 2562531Swollman ++igmpstat.igps_rcv_badqueries; 2572531Swollman m_freem(m); 2582531Swollman return; 2592531Swollman } 26014622Sfenner } else { 2612531Swollman /* 26214622Sfenner * New router. Simply do the new validity check. 2632531Swollman */ 26414622Sfenner 26514622Sfenner if (igmp->igmp_group.s_addr != 0 && 26614622Sfenner !IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) { 26714622Sfenner ++igmpstat.igps_rcv_badqueries; 26814622Sfenner m_freem(m); 26914622Sfenner return; 27014622Sfenner } 27114622Sfenner } 2722531Swollman 27314622Sfenner /* 27414622Sfenner * - Start the timers in all of our membership records 27514622Sfenner * that the query applies to for the interface on 27614622Sfenner * which the query arrived excl. those that belong 27714622Sfenner * to the "all-hosts" group (224.0.0.1). 27814622Sfenner * - Restart any timer that is already running but has 27914622Sfenner * a value longer than the requested timeout. 28014622Sfenner * - Use the value specified in the query message as 28114622Sfenner * the maximum timeout. 28214622Sfenner */ 28314622Sfenner IN_FIRST_MULTI(step, inm); 28414622Sfenner while (inm != NULL) { 28514622Sfenner if (inm->inm_ifp == ifp && 28614622Sfenner inm->inm_addr.s_addr != igmp_all_hosts_group && 28714622Sfenner (igmp->igmp_group.s_addr == 0 || 28814622Sfenner igmp->igmp_group.s_addr == inm->inm_addr.s_addr)) { 28914622Sfenner if (inm->inm_timer == 0 || 29014622Sfenner inm->inm_timer > timer) { 29114622Sfenner inm->inm_timer = 29214622Sfenner IGMP_RANDOM_DELAY(timer); 2932531Swollman igmp_timers_are_running = 1; 2942531Swollman } 2951541Srgrimes } 2961541Srgrimes IN_NEXT_MULTI(step, inm); 2971541Srgrimes } 2989209Swollman 2991541Srgrimes break; 3001541Srgrimes 30114622Sfenner case IGMP_V1_MEMBERSHIP_REPORT: 30214622Sfenner case IGMP_V2_MEMBERSHIP_REPORT: 3039209Swollman /* 30414622Sfenner * For fast leave to work, we have to know that we are the 30514622Sfenner * last person to send a report for this group. Reports 30614622Sfenner * can potentially get looped back if we are a multicast 30714622Sfenner * router, so discard reports sourced by me. 3089209Swollman */ 30914622Sfenner IFP_TO_IA(ifp, ia); 31014622Sfenner if (ia && ip->ip_src.s_addr == IA_SIN(ia)->sin_addr.s_addr) 31114622Sfenner break; 31214622Sfenner 3131541Srgrimes ++igmpstat.igps_rcv_reports; 3141541Srgrimes 3158090Spst if (ifp->if_flags & IFF_LOOPBACK) 3161541Srgrimes break; 3171541Srgrimes 31814622Sfenner if (!IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) { 3191541Srgrimes ++igmpstat.igps_rcv_badreports; 3201541Srgrimes m_freem(m); 3211541Srgrimes return; 3221541Srgrimes } 3231541Srgrimes 3241541Srgrimes /* 3251541Srgrimes * KLUDGE: if the IP source address of the report has an 3261541Srgrimes * unspecified (i.e., zero) subnet number, as is allowed for 3271541Srgrimes * a booting host, replace it with the correct subnet number 32896432Sdd * so that a process-level multicast routing daemon can 3291541Srgrimes * determine which subnet it arrived from. This is necessary 3301541Srgrimes * to compensate for the lack of any way for a process to 3311541Srgrimes * determine the arrival interface of an incoming packet. 3321541Srgrimes */ 33314622Sfenner if ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) == 0) 3341541Srgrimes if (ia) ip->ip_src.s_addr = htonl(ia->ia_subnet); 3351541Srgrimes 3361541Srgrimes /* 3371541Srgrimes * If we belong to the group being reported, stop 3381541Srgrimes * our timer for that group. 3391541Srgrimes */ 3401541Srgrimes IN_LOOKUP_MULTI(igmp->igmp_group, ifp, inm); 3411541Srgrimes 3422531Swollman if (inm != NULL) { 34314622Sfenner inm->inm_timer = 0; 34414622Sfenner ++igmpstat.igps_rcv_ourreports; 34514622Sfenner 34614622Sfenner inm->inm_state = IGMP_OTHERMEMBER; 3472531Swollman } 34814622Sfenner 3491541Srgrimes break; 3501541Srgrimes } 3511541Srgrimes 3521541Srgrimes /* 3531541Srgrimes * Pass all valid IGMP packets up to any process(es) listening 3541541Srgrimes * on a raw IGMP socket. 3551541Srgrimes */ 35682890Sjulian rip_input(m, off); 3571541Srgrimes} 3581541Srgrimes 3591541Srgrimesvoid 360119181Srwatsonigmp_joingroup(struct in_multi *inm) 3611541Srgrimes{ 3629209Swollman int s = splnet(); 3631541Srgrimes 36414622Sfenner if (inm->inm_addr.s_addr == igmp_all_hosts_group 36514622Sfenner || inm->inm_ifp->if_flags & IFF_LOOPBACK) { 3661541Srgrimes inm->inm_timer = 0; 36714622Sfenner inm->inm_state = IGMP_OTHERMEMBER; 36814622Sfenner } else { 369130333Srwatson mtx_lock(&igmp_mtx); 37014622Sfenner inm->inm_rti = find_rti(inm->inm_ifp); 371130333Srwatson mtx_unlock(&igmp_mtx); 37214622Sfenner igmp_sendpkt(inm, inm->inm_rti->rti_type, 0); 3732531Swollman inm->inm_timer = IGMP_RANDOM_DELAY( 3742531Swollman IGMP_MAX_HOST_REPORT_DELAY*PR_FASTHZ); 37514622Sfenner inm->inm_state = IGMP_IREPORTEDLAST; 3761541Srgrimes igmp_timers_are_running = 1; 3771541Srgrimes } 3781541Srgrimes splx(s); 3791541Srgrimes} 3801541Srgrimes 3811541Srgrimesvoid 382119181Srwatsonigmp_leavegroup(struct in_multi *inm) 3831541Srgrimes{ 384119181Srwatson 38514622Sfenner if (inm->inm_state == IGMP_IREPORTEDLAST && 38614622Sfenner inm->inm_addr.s_addr != igmp_all_hosts_group && 38714622Sfenner !(inm->inm_ifp->if_flags & IFF_LOOPBACK) && 38814622Sfenner inm->inm_rti->rti_type != IGMP_V1_ROUTER) 38914622Sfenner igmp_sendpkt(inm, IGMP_V2_LEAVE_GROUP, igmp_all_rtrs_group); 3901541Srgrimes} 3911541Srgrimes 3921541Srgrimesvoid 393119181Srwatsonigmp_fasttimo(void) 3941541Srgrimes{ 395107113Sluigi register struct in_multi *inm; 3961541Srgrimes struct in_multistep step; 3979209Swollman int s; 3981541Srgrimes 3991541Srgrimes /* 4001541Srgrimes * Quick check to see if any work needs to be done, in order 4011541Srgrimes * to minimize the overhead of fasttimo processing. 4021541Srgrimes */ 4039209Swollman 4041541Srgrimes if (!igmp_timers_are_running) 4051541Srgrimes return; 4061541Srgrimes 4071541Srgrimes s = splnet(); 4081541Srgrimes igmp_timers_are_running = 0; 4091541Srgrimes IN_FIRST_MULTI(step, inm); 4101541Srgrimes while (inm != NULL) { 4111541Srgrimes if (inm->inm_timer == 0) { 4121541Srgrimes /* do nothing */ 4131541Srgrimes } else if (--inm->inm_timer == 0) { 41414622Sfenner igmp_sendpkt(inm, inm->inm_rti->rti_type, 0); 41514622Sfenner inm->inm_state = IGMP_IREPORTEDLAST; 4161541Srgrimes } else { 4171541Srgrimes igmp_timers_are_running = 1; 4181541Srgrimes } 4191541Srgrimes IN_NEXT_MULTI(step, inm); 4201541Srgrimes } 4211541Srgrimes splx(s); 4221541Srgrimes} 4231541Srgrimes 4242531Swollmanvoid 425119181Srwatsonigmp_slowtimo(void) 4262531Swollman{ 4272531Swollman int s = splnet(); 428119180Srwatson struct router_info *rti; 4292531Swollman 430119180Srwatson IGMP_PRINTF("[igmp.c,_slowtimo] -- > entering \n"); 431130333Srwatson mtx_lock(&igmp_mtx); 432119180Srwatson SLIST_FOREACH(rti, &router_info_head, rti_list) { 433119181Srwatson if (rti->rti_type == IGMP_V1_ROUTER) { 434119181Srwatson rti->rti_time++; 435119181Srwatson if (rti->rti_time >= IGMP_AGE_THRESHOLD) 436119181Srwatson rti->rti_type = IGMP_V2_ROUTER; 4372531Swollman } 4382531Swollman } 439130333Srwatson mtx_unlock(&igmp_mtx); 440119180Srwatson IGMP_PRINTF("[igmp.c,_slowtimo] -- > exiting \n"); 4412531Swollman splx(s); 4422531Swollman} 4432531Swollman 4441541Srgrimesstatic void 445119181Srwatsonigmp_sendpkt(struct in_multi *inm, int type, unsigned long addr) 4461541Srgrimes{ 447119181Srwatson struct mbuf *m; 448119181Srwatson struct igmp *igmp; 449119181Srwatson struct ip *ip; 450119181Srwatson struct ip_moptions imo; 4511541Srgrimes 452119181Srwatson MGETHDR(m, M_DONTWAIT, MT_HEADER); 453119181Srwatson if (m == NULL) 454119181Srwatson return; 4552531Swollman 4568090Spst m->m_pkthdr.rcvif = loif; 457101091Srwatson#ifdef MAC 458101091Srwatson mac_create_mbuf_linklayer(inm->inm_ifp, m); 459101091Srwatson#endif 4601541Srgrimes m->m_pkthdr.len = sizeof(struct ip) + IGMP_MINLEN; 4612531Swollman MH_ALIGN(m, IGMP_MINLEN + sizeof(struct ip)); 4622531Swollman m->m_data += sizeof(struct ip); 463119181Srwatson m->m_len = IGMP_MINLEN; 464119181Srwatson igmp = mtod(m, struct igmp *); 465119181Srwatson igmp->igmp_type = type; 466119181Srwatson igmp->igmp_code = 0; 467119181Srwatson igmp->igmp_group = inm->inm_addr; 468119181Srwatson igmp->igmp_cksum = 0; 469119181Srwatson igmp->igmp_cksum = in_cksum(m, IGMP_MINLEN); 4701541Srgrimes 471119181Srwatson m->m_data -= sizeof(struct ip); 472119181Srwatson m->m_len += sizeof(struct ip); 473119181Srwatson ip = mtod(m, struct ip *); 474119181Srwatson ip->ip_tos = 0; 475119181Srwatson ip->ip_len = sizeof(struct ip) + IGMP_MINLEN; 476119181Srwatson ip->ip_off = 0; 477119181Srwatson ip->ip_p = IPPROTO_IGMP; 478119181Srwatson ip->ip_src.s_addr = INADDR_ANY; 479119181Srwatson ip->ip_dst.s_addr = addr ? addr : igmp->igmp_group.s_addr; 4801541Srgrimes 481119181Srwatson imo.imo_multicast_ifp = inm->inm_ifp; 482119181Srwatson imo.imo_multicast_ttl = 1; 48315292Swollman imo.imo_multicast_vif = -1; 484119181Srwatson /* 485119181Srwatson * Request loopback of the report if we are acting as a multicast 486119181Srwatson * router, so that the process-level routing daemon can hear it. 487119181Srwatson */ 488119181Srwatson imo.imo_multicast_loop = (ip_mrouter != NULL); 4891541Srgrimes 49015292Swollman /* 49115292Swollman * XXX 49215292Swollman * Do we have to worry about reentrancy here? Don't think so. 49315292Swollman */ 494119181Srwatson ip_output(m, router_alert, &igmprt, 0, &imo, NULL); 4952531Swollman 496119181Srwatson ++igmpstat.igps_snd_reports; 4971541Srgrimes} 498