igmp.c revision 152592
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 152592 2005-11-18 20:12:40Z andre $ 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> 68152592Sandre#include <netinet/ip_options.h> 691541Srgrimes#include <netinet/igmp.h> 701541Srgrimes#include <netinet/igmp_var.h> 711541Srgrimes 7260105Sjlemon#include <machine/in_cksum.h> 7360105Sjlemon 7442776Sfennerstatic MALLOC_DEFINE(M_IGMP, "igmp", "igmp state"); 7530309Sphk 76119181Srwatsonstatic struct router_info *find_rti(struct ifnet *ifp); 77119181Srwatsonstatic void igmp_sendpkt(struct in_multi *, int, unsigned long); 7812579Sbde 7912704Sphkstatic struct igmpstat igmpstat; 802531Swollman 81119181SrwatsonSYSCTL_STRUCT(_net_inet_igmp, IGMPCTL_STATS, stats, CTLFLAG_RW, &igmpstat, 82119181Srwatson igmpstat, ""); 8312296Sphk 84130333Srwatson/* 85130333Srwatson * igmp_mtx protects all mutable global variables in igmp.c, as well as 86130333Srwatson * the data fields in struct router_info. In general, a router_info 87130333Srwatson * structure will be valid as long as the referencing struct in_multi is 88130333Srwatson * valid, so no reference counting is used. We allow unlocked reads of 89130333Srwatson * router_info data when accessed via an in_multi read-only. 90130333Srwatson */ 91130333Srwatsonstatic struct mtx igmp_mtx; 92119181Srwatsonstatic SLIST_HEAD(, router_info) router_info_head; 939209Swollmanstatic int igmp_timers_are_running; 94130333Srwatson 95130333Srwatson/* 96130333Srwatson * XXXRW: can we define these such that these can be made const? In any 97130333Srwatson * case, these shouldn't be changed after igmp_init() and therefore don't 98130333Srwatson * need locking. 99130333Srwatson */ 1001541Srgrimesstatic u_long igmp_all_hosts_group; 10114622Sfennerstatic u_long igmp_all_rtrs_group; 102130333Srwatson 10314622Sfennerstatic struct mbuf *router_alert; 104119181Srwatsonstatic struct route igmprt; 1051541Srgrimes 106119180Srwatson#ifdef IGMP_DEBUG 107119180Srwatson#define IGMP_PRINTF(x) printf(x) 108119180Srwatson#else 109119180Srwatson#define IGMP_PRINTF(x) 110119180Srwatson#endif 111119180Srwatson 1121541Srgrimesvoid 113119181Srwatsonigmp_init(void) 1141541Srgrimes{ 11514622Sfenner struct ipoption *ra; 11614622Sfenner 1171541Srgrimes /* 1181541Srgrimes * To avoid byte-swapping the same value over and over again. 1191541Srgrimes */ 1201541Srgrimes igmp_all_hosts_group = htonl(INADDR_ALLHOSTS_GROUP); 12114622Sfenner igmp_all_rtrs_group = htonl(INADDR_ALLRTRS_GROUP); 1229209Swollman 1239209Swollman igmp_timers_are_running = 0; 1249209Swollman 12514622Sfenner /* 12614622Sfenner * Construct a Router Alert option to use in outgoing packets 12714622Sfenner */ 128111119Simp MGET(router_alert, M_DONTWAIT, MT_DATA); 12914622Sfenner ra = mtod(router_alert, struct ipoption *); 13014622Sfenner ra->ipopt_dst.s_addr = 0; 13114622Sfenner ra->ipopt_list[0] = IPOPT_RA; /* Router Alert Option */ 13214622Sfenner ra->ipopt_list[1] = 0x04; /* 4 bytes long */ 13314622Sfenner ra->ipopt_list[2] = 0x00; 13414622Sfenner ra->ipopt_list[3] = 0x00; 13514622Sfenner router_alert->m_len = sizeof(ra->ipopt_dst) + ra->ipopt_list[1]; 13614622Sfenner 137130333Srwatson mtx_init(&igmp_mtx, "igmp_mtx", NULL, MTX_DEF); 138119180Srwatson SLIST_INIT(&router_info_head); 1391541Srgrimes} 1401541Srgrimes 14112704Sphkstatic struct router_info * 142119181Srwatsonfind_rti(struct ifnet *ifp) 1432531Swollman{ 144119180Srwatson struct router_info *rti; 1452531Swollman 146130333Srwatson mtx_assert(&igmp_mtx, MA_OWNED); 147119180Srwatson IGMP_PRINTF("[igmp.c, _find_rti] --> entering \n"); 148119180Srwatson SLIST_FOREACH(rti, &router_info_head, rti_list) { 149119180Srwatson if (rti->rti_ifp == ifp) { 150119180Srwatson IGMP_PRINTF( 151119180Srwatson "[igmp.c, _find_rti] --> found old entry \n"); 152119181Srwatson return rti; 153119181Srwatson } 154119181Srwatson } 15542776Sfenner MALLOC(rti, struct router_info *, sizeof *rti, M_IGMP, M_NOWAIT); 156144163Ssam if (rti == NULL) { 157144163Ssam IGMP_PRINTF( "[igmp.c, _find_rti] --> no memory for entry\n"); 158144163Ssam return NULL; 159144163Ssam } 160119181Srwatson rti->rti_ifp = ifp; 161119181Srwatson rti->rti_type = IGMP_V2_ROUTER; 162119181Srwatson rti->rti_time = 0; 163119180Srwatson SLIST_INSERT_HEAD(&router_info_head, rti, rti_list); 164119180Srwatson 165119180Srwatson IGMP_PRINTF("[igmp.c, _find_rti] --> created an entry \n"); 166119181Srwatson return rti; 1672531Swollman} 1682531Swollman 1691541Srgrimesvoid 170119181Srwatsonigmp_input(register struct mbuf *m, int off) 1711541Srgrimes{ 172107113Sluigi register int iphlen = off; 173107113Sluigi register struct igmp *igmp; 174107113Sluigi register struct ip *ip; 175107113Sluigi register int igmplen; 176107113Sluigi register struct ifnet *ifp = m->m_pkthdr.rcvif; 177107113Sluigi register int minlen; 178107113Sluigi register struct in_multi *inm; 179107113Sluigi register struct in_ifaddr *ia; 1801541Srgrimes struct in_multistep step; 1812531Swollman struct router_info *rti; 1828546Sdg int timer; /** timer value in the igmp query header **/ 1831541Srgrimes 1841541Srgrimes ++igmpstat.igps_rcv_total; 1851541Srgrimes 1861541Srgrimes ip = mtod(m, struct ip *); 1871541Srgrimes igmplen = ip->ip_len; 1881541Srgrimes 1891541Srgrimes /* 1901541Srgrimes * Validate lengths 1911541Srgrimes */ 1921541Srgrimes if (igmplen < IGMP_MINLEN) { 1931541Srgrimes ++igmpstat.igps_rcv_tooshort; 1941541Srgrimes m_freem(m); 1951541Srgrimes return; 1961541Srgrimes } 1971541Srgrimes minlen = iphlen + IGMP_MINLEN; 1981541Srgrimes if ((m->m_flags & M_EXT || m->m_len < minlen) && 1991541Srgrimes (m = m_pullup(m, minlen)) == 0) { 2001541Srgrimes ++igmpstat.igps_rcv_tooshort; 2011541Srgrimes return; 2021541Srgrimes } 2031541Srgrimes 2041541Srgrimes /* 2051541Srgrimes * Validate checksum 2061541Srgrimes */ 2071541Srgrimes m->m_data += iphlen; 2081541Srgrimes m->m_len -= iphlen; 2091541Srgrimes igmp = mtod(m, struct igmp *); 2101541Srgrimes if (in_cksum(m, igmplen)) { 2111541Srgrimes ++igmpstat.igps_rcv_badsum; 2121541Srgrimes m_freem(m); 2131541Srgrimes return; 2141541Srgrimes } 2151541Srgrimes m->m_data -= iphlen; 2161541Srgrimes m->m_len += iphlen; 2172531Swollman 2181541Srgrimes ip = mtod(m, struct ip *); 2198546Sdg timer = igmp->igmp_code * PR_FASTHZ / IGMP_TIMER_SCALE; 22041702Sdillon if (timer == 0) 22141702Sdillon timer = 1; 2221541Srgrimes 22314622Sfenner /* 22414622Sfenner * In the IGMPv2 specification, there are 3 states and a flag. 22514622Sfenner * 22614622Sfenner * In Non-Member state, we simply don't have a membership record. 22714622Sfenner * In Delaying Member state, our timer is running (inm->inm_timer) 22814622Sfenner * In Idle Member state, our timer is not running (inm->inm_timer==0) 22914622Sfenner * 23014622Sfenner * The flag is inm->inm_state, it is set to IGMP_OTHERMEMBER if 23114622Sfenner * we have heard a report from another member, or IGMP_IREPORTEDLAST 23214622Sfenner * if I sent the last report. 23314622Sfenner */ 2341541Srgrimes switch (igmp->igmp_type) { 23514622Sfenner case IGMP_MEMBERSHIP_QUERY: 2361541Srgrimes ++igmpstat.igps_rcv_queries; 2371541Srgrimes 2388090Spst if (ifp->if_flags & IFF_LOOPBACK) 2391541Srgrimes break; 2401541Srgrimes 2412531Swollman if (igmp->igmp_code == 0) { 24214622Sfenner /* 24314622Sfenner * Old router. Remember that the querier on this 24414622Sfenner * interface is old, and set the timer to the 24514622Sfenner * value in RFC 1112. 24614622Sfenner */ 2474028Spst 248130333Srwatson mtx_lock(&igmp_mtx); 249130333Srwatson rti = find_rti(ifp); 250144163Ssam if (rti == NULL) { 251144163Ssam mtx_unlock(&igmp_mtx); 252144163Ssam m_freem(m); 253144163Ssam return; 254144163Ssam } 25514622Sfenner rti->rti_type = IGMP_V1_ROUTER; 25614622Sfenner rti->rti_time = 0; 257130333Srwatson mtx_unlock(&igmp_mtx); 2584028Spst 25914622Sfenner timer = IGMP_MAX_HOST_REPORT_DELAY * PR_FASTHZ; 2604028Spst 26114622Sfenner if (ip->ip_dst.s_addr != igmp_all_hosts_group || 26214622Sfenner igmp->igmp_group.s_addr != 0) { 2632531Swollman ++igmpstat.igps_rcv_badqueries; 2642531Swollman m_freem(m); 2652531Swollman return; 2662531Swollman } 26714622Sfenner } else { 2682531Swollman /* 26914622Sfenner * New router. Simply do the new validity check. 2702531Swollman */ 27114622Sfenner 27214622Sfenner if (igmp->igmp_group.s_addr != 0 && 27314622Sfenner !IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) { 27414622Sfenner ++igmpstat.igps_rcv_badqueries; 27514622Sfenner m_freem(m); 27614622Sfenner return; 27714622Sfenner } 27814622Sfenner } 2792531Swollman 28014622Sfenner /* 28114622Sfenner * - Start the timers in all of our membership records 28214622Sfenner * that the query applies to for the interface on 28314622Sfenner * which the query arrived excl. those that belong 28414622Sfenner * to the "all-hosts" group (224.0.0.1). 28514622Sfenner * - Restart any timer that is already running but has 28614622Sfenner * a value longer than the requested timeout. 28714622Sfenner * - Use the value specified in the query message as 28814622Sfenner * the maximum timeout. 28914622Sfenner */ 290148682Srwatson IN_MULTI_LOCK(); 29114622Sfenner IN_FIRST_MULTI(step, inm); 29214622Sfenner while (inm != NULL) { 29314622Sfenner if (inm->inm_ifp == ifp && 29414622Sfenner inm->inm_addr.s_addr != igmp_all_hosts_group && 29514622Sfenner (igmp->igmp_group.s_addr == 0 || 29614622Sfenner igmp->igmp_group.s_addr == inm->inm_addr.s_addr)) { 29714622Sfenner if (inm->inm_timer == 0 || 29814622Sfenner inm->inm_timer > timer) { 29914622Sfenner inm->inm_timer = 30014622Sfenner IGMP_RANDOM_DELAY(timer); 3012531Swollman igmp_timers_are_running = 1; 3022531Swollman } 3031541Srgrimes } 3041541Srgrimes IN_NEXT_MULTI(step, inm); 3051541Srgrimes } 306148682Srwatson IN_MULTI_UNLOCK(); 3079209Swollman 3081541Srgrimes break; 3091541Srgrimes 31014622Sfenner case IGMP_V1_MEMBERSHIP_REPORT: 31114622Sfenner case IGMP_V2_MEMBERSHIP_REPORT: 3129209Swollman /* 31314622Sfenner * For fast leave to work, we have to know that we are the 31414622Sfenner * last person to send a report for this group. Reports 31514622Sfenner * can potentially get looped back if we are a multicast 31614622Sfenner * router, so discard reports sourced by me. 3179209Swollman */ 31814622Sfenner IFP_TO_IA(ifp, ia); 31914622Sfenner if (ia && ip->ip_src.s_addr == IA_SIN(ia)->sin_addr.s_addr) 32014622Sfenner break; 32114622Sfenner 3221541Srgrimes ++igmpstat.igps_rcv_reports; 3231541Srgrimes 3248090Spst if (ifp->if_flags & IFF_LOOPBACK) 3251541Srgrimes break; 3261541Srgrimes 32714622Sfenner if (!IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) { 3281541Srgrimes ++igmpstat.igps_rcv_badreports; 3291541Srgrimes m_freem(m); 3301541Srgrimes return; 3311541Srgrimes } 3321541Srgrimes 3331541Srgrimes /* 3341541Srgrimes * KLUDGE: if the IP source address of the report has an 3351541Srgrimes * unspecified (i.e., zero) subnet number, as is allowed for 3361541Srgrimes * a booting host, replace it with the correct subnet number 33796432Sdd * so that a process-level multicast routing daemon can 3381541Srgrimes * determine which subnet it arrived from. This is necessary 3391541Srgrimes * to compensate for the lack of any way for a process to 3401541Srgrimes * determine the arrival interface of an incoming packet. 3411541Srgrimes */ 34214622Sfenner if ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) == 0) 3431541Srgrimes if (ia) ip->ip_src.s_addr = htonl(ia->ia_subnet); 3441541Srgrimes 3451541Srgrimes /* 3461541Srgrimes * If we belong to the group being reported, stop 3471541Srgrimes * our timer for that group. 3481541Srgrimes */ 349148682Srwatson IN_MULTI_LOCK(); 3501541Srgrimes IN_LOOKUP_MULTI(igmp->igmp_group, ifp, inm); 3512531Swollman if (inm != NULL) { 35214622Sfenner inm->inm_timer = 0; 35314622Sfenner ++igmpstat.igps_rcv_ourreports; 35414622Sfenner 35514622Sfenner inm->inm_state = IGMP_OTHERMEMBER; 3562531Swollman } 357148682Srwatson IN_MULTI_UNLOCK(); 35814622Sfenner 3591541Srgrimes break; 3601541Srgrimes } 3611541Srgrimes 3621541Srgrimes /* 3631541Srgrimes * Pass all valid IGMP packets up to any process(es) listening 3641541Srgrimes * on a raw IGMP socket. 3651541Srgrimes */ 36682890Sjulian rip_input(m, off); 3671541Srgrimes} 3681541Srgrimes 3691541Srgrimesvoid 370119181Srwatsonigmp_joingroup(struct in_multi *inm) 3711541Srgrimes{ 3721541Srgrimes 373148682Srwatson IN_MULTI_LOCK_ASSERT(); 374148682Srwatson 37514622Sfenner if (inm->inm_addr.s_addr == igmp_all_hosts_group 37614622Sfenner || inm->inm_ifp->if_flags & IFF_LOOPBACK) { 3771541Srgrimes inm->inm_timer = 0; 37814622Sfenner inm->inm_state = IGMP_OTHERMEMBER; 37914622Sfenner } else { 380130333Srwatson mtx_lock(&igmp_mtx); 38114622Sfenner inm->inm_rti = find_rti(inm->inm_ifp); 382130333Srwatson mtx_unlock(&igmp_mtx); 383144163Ssam if (inm->inm_rti != NULL) { 384144163Ssam igmp_sendpkt(inm, inm->inm_rti->rti_type, 0); 385144163Ssam inm->inm_timer = IGMP_RANDOM_DELAY( 3862531Swollman IGMP_MAX_HOST_REPORT_DELAY*PR_FASTHZ); 387144163Ssam inm->inm_state = IGMP_IREPORTEDLAST; 388144163Ssam igmp_timers_are_running = 1; 389144163Ssam } 390144163Ssam /* XXX handling of failure case? */ 3911541Srgrimes } 3921541Srgrimes} 3931541Srgrimes 3941541Srgrimesvoid 395119181Srwatsonigmp_leavegroup(struct in_multi *inm) 3961541Srgrimes{ 397119181Srwatson 398148682Srwatson IN_MULTI_LOCK_ASSERT(); 399148682Srwatson 40014622Sfenner if (inm->inm_state == IGMP_IREPORTEDLAST && 40114622Sfenner inm->inm_addr.s_addr != igmp_all_hosts_group && 40214622Sfenner !(inm->inm_ifp->if_flags & IFF_LOOPBACK) && 40314622Sfenner inm->inm_rti->rti_type != IGMP_V1_ROUTER) 40414622Sfenner igmp_sendpkt(inm, IGMP_V2_LEAVE_GROUP, igmp_all_rtrs_group); 4051541Srgrimes} 4061541Srgrimes 4071541Srgrimesvoid 408119181Srwatsonigmp_fasttimo(void) 4091541Srgrimes{ 410107113Sluigi register struct in_multi *inm; 4111541Srgrimes struct in_multistep step; 4121541Srgrimes 4131541Srgrimes /* 4141541Srgrimes * Quick check to see if any work needs to be done, in order 4151541Srgrimes * to minimize the overhead of fasttimo processing. 4161541Srgrimes */ 4179209Swollman 4181541Srgrimes if (!igmp_timers_are_running) 4191541Srgrimes return; 4201541Srgrimes 421148682Srwatson IN_MULTI_LOCK(); 4221541Srgrimes igmp_timers_are_running = 0; 4231541Srgrimes IN_FIRST_MULTI(step, inm); 4241541Srgrimes while (inm != NULL) { 4251541Srgrimes if (inm->inm_timer == 0) { 4261541Srgrimes /* do nothing */ 4271541Srgrimes } else if (--inm->inm_timer == 0) { 42814622Sfenner igmp_sendpkt(inm, inm->inm_rti->rti_type, 0); 42914622Sfenner inm->inm_state = IGMP_IREPORTEDLAST; 4301541Srgrimes } else { 4311541Srgrimes igmp_timers_are_running = 1; 4321541Srgrimes } 4331541Srgrimes IN_NEXT_MULTI(step, inm); 4341541Srgrimes } 435148682Srwatson IN_MULTI_UNLOCK(); 4361541Srgrimes} 4371541Srgrimes 4382531Swollmanvoid 439119181Srwatsonigmp_slowtimo(void) 4402531Swollman{ 441119180Srwatson struct router_info *rti; 4422531Swollman 443119180Srwatson IGMP_PRINTF("[igmp.c,_slowtimo] -- > entering \n"); 444130333Srwatson mtx_lock(&igmp_mtx); 445119180Srwatson SLIST_FOREACH(rti, &router_info_head, rti_list) { 446119181Srwatson if (rti->rti_type == IGMP_V1_ROUTER) { 447119181Srwatson rti->rti_time++; 448119181Srwatson if (rti->rti_time >= IGMP_AGE_THRESHOLD) 449119181Srwatson rti->rti_type = IGMP_V2_ROUTER; 4502531Swollman } 4512531Swollman } 452130333Srwatson mtx_unlock(&igmp_mtx); 453119180Srwatson IGMP_PRINTF("[igmp.c,_slowtimo] -- > exiting \n"); 4542531Swollman} 4552531Swollman 4561541Srgrimesstatic void 457119181Srwatsonigmp_sendpkt(struct in_multi *inm, int type, unsigned long addr) 4581541Srgrimes{ 459119181Srwatson struct mbuf *m; 460119181Srwatson struct igmp *igmp; 461119181Srwatson struct ip *ip; 462119181Srwatson struct ip_moptions imo; 4631541Srgrimes 464148682Srwatson IN_MULTI_LOCK_ASSERT(); 465148682Srwatson 466151967Sandre MGETHDR(m, M_DONTWAIT, MT_DATA); 467119181Srwatson if (m == NULL) 468119181Srwatson return; 4692531Swollman 4708090Spst m->m_pkthdr.rcvif = loif; 471101091Srwatson#ifdef MAC 472101091Srwatson mac_create_mbuf_linklayer(inm->inm_ifp, m); 473101091Srwatson#endif 4741541Srgrimes m->m_pkthdr.len = sizeof(struct ip) + IGMP_MINLEN; 4752531Swollman MH_ALIGN(m, IGMP_MINLEN + sizeof(struct ip)); 4762531Swollman m->m_data += sizeof(struct ip); 477119181Srwatson m->m_len = IGMP_MINLEN; 478119181Srwatson igmp = mtod(m, struct igmp *); 479119181Srwatson igmp->igmp_type = type; 480119181Srwatson igmp->igmp_code = 0; 481119181Srwatson igmp->igmp_group = inm->inm_addr; 482119181Srwatson igmp->igmp_cksum = 0; 483119181Srwatson igmp->igmp_cksum = in_cksum(m, IGMP_MINLEN); 4841541Srgrimes 485119181Srwatson m->m_data -= sizeof(struct ip); 486119181Srwatson m->m_len += sizeof(struct ip); 487119181Srwatson ip = mtod(m, struct ip *); 488119181Srwatson ip->ip_tos = 0; 489119181Srwatson ip->ip_len = sizeof(struct ip) + IGMP_MINLEN; 490119181Srwatson ip->ip_off = 0; 491119181Srwatson ip->ip_p = IPPROTO_IGMP; 492119181Srwatson ip->ip_src.s_addr = INADDR_ANY; 493119181Srwatson ip->ip_dst.s_addr = addr ? addr : igmp->igmp_group.s_addr; 4941541Srgrimes 495119181Srwatson imo.imo_multicast_ifp = inm->inm_ifp; 496119181Srwatson imo.imo_multicast_ttl = 1; 49715292Swollman imo.imo_multicast_vif = -1; 498119181Srwatson /* 499119181Srwatson * Request loopback of the report if we are acting as a multicast 500119181Srwatson * router, so that the process-level routing daemon can hear it. 501119181Srwatson */ 502119181Srwatson imo.imo_multicast_loop = (ip_mrouter != NULL); 5031541Srgrimes 50415292Swollman /* 50515292Swollman * XXX 50615292Swollman * Do we have to worry about reentrancy here? Don't think so. 50715292Swollman */ 508119181Srwatson ip_output(m, router_alert, &igmprt, 0, &imo, NULL); 5092531Swollman 510119181Srwatson ++igmpstat.igps_snd_reports; 5111541Srgrimes} 512