481 lines
13 KiB
C
481 lines
13 KiB
C
/*
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* Copyright (c) 1988 Stephen Deering.
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* Copyright (c) 1992, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Stephen Deering of Stanford University.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)igmp.c 8.1 (Berkeley) 7/19/93
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* $Id: igmp.c,v 1.21 1997/02/22 09:41:26 peter Exp $
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*/
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/*
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* Internet Group Management Protocol (IGMP) routines.
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*
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* Written by Steve Deering, Stanford, May 1988.
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* Modified by Rosen Sharma, Stanford, Aug 1994.
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* Modified by Bill Fenner, Xerox PARC, Feb 1995.
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* Modified to fully comply to IGMPv2 by Bill Fenner, Oct 1995.
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*
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* MULTICAST Revision: 3.5.1.4
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/malloc.h>
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#include <sys/mbuf.h>
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#include <sys/socket.h>
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#include <sys/protosw.h>
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#include <sys/kernel.h>
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#include <sys/sysctl.h>
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#include <net/if.h>
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#include <net/route.h>
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#include <netinet/in.h>
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#include <netinet/in_var.h>
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#include <netinet/in_systm.h>
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#include <netinet/ip.h>
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#include <netinet/ip_var.h>
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#include <netinet/igmp.h>
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#include <netinet/igmp_var.h>
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static struct router_info *
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find_rti __P((struct ifnet *ifp));
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static struct igmpstat igmpstat;
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SYSCTL_STRUCT(_net_inet_igmp, IGMPCTL_STATS, stats, CTLFLAG_RD,
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&igmpstat, igmpstat, "");
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static int igmp_timers_are_running;
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static u_long igmp_all_hosts_group;
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static u_long igmp_all_rtrs_group;
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static struct mbuf *router_alert;
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static struct router_info *Head;
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static void igmp_sendpkt(struct in_multi *, int, unsigned long);
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void
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igmp_init()
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{
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struct ipoption *ra;
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/*
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* To avoid byte-swapping the same value over and over again.
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*/
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igmp_all_hosts_group = htonl(INADDR_ALLHOSTS_GROUP);
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igmp_all_rtrs_group = htonl(INADDR_ALLRTRS_GROUP);
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igmp_timers_are_running = 0;
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/*
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* Construct a Router Alert option to use in outgoing packets
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*/
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MGET(router_alert, M_DONTWAIT, MT_DATA);
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ra = mtod(router_alert, struct ipoption *);
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ra->ipopt_dst.s_addr = 0;
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ra->ipopt_list[0] = IPOPT_RA; /* Router Alert Option */
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ra->ipopt_list[1] = 0x04; /* 4 bytes long */
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ra->ipopt_list[2] = 0x00;
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ra->ipopt_list[3] = 0x00;
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router_alert->m_len = sizeof(ra->ipopt_dst) + ra->ipopt_list[1];
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Head = (struct router_info *) 0;
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}
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static struct router_info *
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find_rti(ifp)
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struct ifnet *ifp;
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{
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register struct router_info *rti = Head;
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#ifdef IGMP_DEBUG
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printf("[igmp.c, _find_rti] --> entering \n");
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#endif
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while (rti) {
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if (rti->rti_ifp == ifp) {
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#ifdef IGMP_DEBUG
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printf("[igmp.c, _find_rti] --> found old entry \n");
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#endif
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return rti;
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}
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rti = rti->rti_next;
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}
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MALLOC(rti, struct router_info *, sizeof *rti, M_MRTABLE, M_NOWAIT);
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rti->rti_ifp = ifp;
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rti->rti_type = IGMP_V2_ROUTER;
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rti->rti_time = 0;
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rti->rti_next = Head;
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Head = rti;
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#ifdef IGMP_DEBUG
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printf("[igmp.c, _find_rti] --> created an entry \n");
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#endif
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return rti;
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}
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void
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igmp_input(m, iphlen)
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register struct mbuf *m;
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register int iphlen;
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{
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register struct igmp *igmp;
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register struct ip *ip;
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register int igmplen;
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register struct ifnet *ifp = m->m_pkthdr.rcvif;
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register int minlen;
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register struct in_multi *inm;
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register struct in_ifaddr *ia;
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struct in_multistep step;
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struct router_info *rti;
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int timer; /** timer value in the igmp query header **/
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++igmpstat.igps_rcv_total;
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ip = mtod(m, struct ip *);
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igmplen = ip->ip_len;
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/*
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* Validate lengths
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*/
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if (igmplen < IGMP_MINLEN) {
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++igmpstat.igps_rcv_tooshort;
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m_freem(m);
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return;
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}
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minlen = iphlen + IGMP_MINLEN;
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if ((m->m_flags & M_EXT || m->m_len < minlen) &&
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(m = m_pullup(m, minlen)) == 0) {
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++igmpstat.igps_rcv_tooshort;
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return;
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}
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/*
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* Validate checksum
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*/
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m->m_data += iphlen;
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m->m_len -= iphlen;
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igmp = mtod(m, struct igmp *);
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if (in_cksum(m, igmplen)) {
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++igmpstat.igps_rcv_badsum;
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m_freem(m);
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return;
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}
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m->m_data -= iphlen;
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m->m_len += iphlen;
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ip = mtod(m, struct ip *);
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timer = igmp->igmp_code * PR_FASTHZ / IGMP_TIMER_SCALE;
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rti = find_rti(ifp);
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/*
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* In the IGMPv2 specification, there are 3 states and a flag.
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*
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* In Non-Member state, we simply don't have a membership record.
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* In Delaying Member state, our timer is running (inm->inm_timer)
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* In Idle Member state, our timer is not running (inm->inm_timer==0)
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*
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* The flag is inm->inm_state, it is set to IGMP_OTHERMEMBER if
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* we have heard a report from another member, or IGMP_IREPORTEDLAST
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* if I sent the last report.
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*/
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switch (igmp->igmp_type) {
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case IGMP_MEMBERSHIP_QUERY:
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++igmpstat.igps_rcv_queries;
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if (ifp->if_flags & IFF_LOOPBACK)
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break;
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if (igmp->igmp_code == 0) {
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/*
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* Old router. Remember that the querier on this
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* interface is old, and set the timer to the
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* value in RFC 1112.
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*/
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rti->rti_type = IGMP_V1_ROUTER;
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rti->rti_time = 0;
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timer = IGMP_MAX_HOST_REPORT_DELAY * PR_FASTHZ;
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if (ip->ip_dst.s_addr != igmp_all_hosts_group ||
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igmp->igmp_group.s_addr != 0) {
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++igmpstat.igps_rcv_badqueries;
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m_freem(m);
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return;
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}
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} else {
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/*
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* New router. Simply do the new validity check.
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*/
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if (igmp->igmp_group.s_addr != 0 &&
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!IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) {
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++igmpstat.igps_rcv_badqueries;
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m_freem(m);
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return;
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}
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}
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/*
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* - Start the timers in all of our membership records
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* that the query applies to for the interface on
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* which the query arrived excl. those that belong
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* to the "all-hosts" group (224.0.0.1).
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* - Restart any timer that is already running but has
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* a value longer than the requested timeout.
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* - Use the value specified in the query message as
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* the maximum timeout.
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*/
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IN_FIRST_MULTI(step, inm);
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while (inm != NULL) {
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if (inm->inm_ifp == ifp &&
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inm->inm_addr.s_addr != igmp_all_hosts_group &&
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(igmp->igmp_group.s_addr == 0 ||
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igmp->igmp_group.s_addr == inm->inm_addr.s_addr)) {
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if (inm->inm_timer == 0 ||
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inm->inm_timer > timer) {
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inm->inm_timer =
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IGMP_RANDOM_DELAY(timer);
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igmp_timers_are_running = 1;
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}
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}
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IN_NEXT_MULTI(step, inm);
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}
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break;
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case IGMP_V1_MEMBERSHIP_REPORT:
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case IGMP_V2_MEMBERSHIP_REPORT:
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/*
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* For fast leave to work, we have to know that we are the
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* last person to send a report for this group. Reports
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* can potentially get looped back if we are a multicast
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* router, so discard reports sourced by me.
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*/
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IFP_TO_IA(ifp, ia);
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if (ia && ip->ip_src.s_addr == IA_SIN(ia)->sin_addr.s_addr)
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break;
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++igmpstat.igps_rcv_reports;
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if (ifp->if_flags & IFF_LOOPBACK)
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break;
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if (!IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) {
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++igmpstat.igps_rcv_badreports;
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m_freem(m);
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return;
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}
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/*
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* KLUDGE: if the IP source address of the report has an
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* unspecified (i.e., zero) subnet number, as is allowed for
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* a booting host, replace it with the correct subnet number
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* so that a process-level multicast routing demon can
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* determine which subnet it arrived from. This is necessary
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* to compensate for the lack of any way for a process to
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* determine the arrival interface of an incoming packet.
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*/
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if ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) == 0)
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if (ia) ip->ip_src.s_addr = htonl(ia->ia_subnet);
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/*
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* If we belong to the group being reported, stop
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* our timer for that group.
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*/
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IN_LOOKUP_MULTI(igmp->igmp_group, ifp, inm);
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if (inm != NULL) {
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inm->inm_timer = 0;
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++igmpstat.igps_rcv_ourreports;
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inm->inm_state = IGMP_OTHERMEMBER;
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}
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break;
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}
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/*
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* Pass all valid IGMP packets up to any process(es) listening
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* on a raw IGMP socket.
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*/
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rip_input(m, iphlen);
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}
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void
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igmp_joingroup(inm)
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struct in_multi *inm;
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{
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int s = splnet();
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if (inm->inm_addr.s_addr == igmp_all_hosts_group
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|| inm->inm_ifp->if_flags & IFF_LOOPBACK) {
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inm->inm_timer = 0;
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inm->inm_state = IGMP_OTHERMEMBER;
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} else {
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inm->inm_rti = find_rti(inm->inm_ifp);
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igmp_sendpkt(inm, inm->inm_rti->rti_type, 0);
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inm->inm_timer = IGMP_RANDOM_DELAY(
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IGMP_MAX_HOST_REPORT_DELAY*PR_FASTHZ);
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inm->inm_state = IGMP_IREPORTEDLAST;
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igmp_timers_are_running = 1;
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}
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splx(s);
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}
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void
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igmp_leavegroup(inm)
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struct in_multi *inm;
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{
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if (inm->inm_state == IGMP_IREPORTEDLAST &&
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inm->inm_addr.s_addr != igmp_all_hosts_group &&
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!(inm->inm_ifp->if_flags & IFF_LOOPBACK) &&
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inm->inm_rti->rti_type != IGMP_V1_ROUTER)
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igmp_sendpkt(inm, IGMP_V2_LEAVE_GROUP, igmp_all_rtrs_group);
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}
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void
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igmp_fasttimo()
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{
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register struct in_multi *inm;
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struct in_multistep step;
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int s;
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/*
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* Quick check to see if any work needs to be done, in order
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* to minimize the overhead of fasttimo processing.
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*/
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if (!igmp_timers_are_running)
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return;
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s = splnet();
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igmp_timers_are_running = 0;
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IN_FIRST_MULTI(step, inm);
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while (inm != NULL) {
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if (inm->inm_timer == 0) {
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/* do nothing */
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} else if (--inm->inm_timer == 0) {
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igmp_sendpkt(inm, inm->inm_rti->rti_type, 0);
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inm->inm_state = IGMP_IREPORTEDLAST;
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} else {
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igmp_timers_are_running = 1;
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}
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IN_NEXT_MULTI(step, inm);
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}
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splx(s);
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}
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void
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igmp_slowtimo()
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{
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int s = splnet();
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register struct router_info *rti = Head;
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#ifdef IGMP_DEBUG
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printf("[igmp.c,_slowtimo] -- > entering \n");
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#endif
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while (rti) {
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if (rti->rti_type == IGMP_V1_ROUTER) {
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rti->rti_time++;
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if (rti->rti_time >= IGMP_AGE_THRESHOLD) {
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rti->rti_type = IGMP_V2_ROUTER;
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}
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}
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rti = rti->rti_next;
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}
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#ifdef IGMP_DEBUG
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printf("[igmp.c,_slowtimo] -- > exiting \n");
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#endif
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splx(s);
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}
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static struct route igmprt;
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static void
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igmp_sendpkt(inm, type, addr)
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struct in_multi *inm;
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int type;
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unsigned long addr;
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{
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struct mbuf *m;
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struct igmp *igmp;
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struct ip *ip;
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struct ip_moptions imo;
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MGETHDR(m, M_DONTWAIT, MT_HEADER);
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if (m == NULL)
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return;
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m->m_pkthdr.rcvif = loif;
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m->m_pkthdr.len = sizeof(struct ip) + IGMP_MINLEN;
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MH_ALIGN(m, IGMP_MINLEN + sizeof(struct ip));
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m->m_data += sizeof(struct ip);
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m->m_len = IGMP_MINLEN;
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igmp = mtod(m, struct igmp *);
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igmp->igmp_type = type;
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igmp->igmp_code = 0;
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igmp->igmp_group = inm->inm_addr;
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igmp->igmp_cksum = 0;
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igmp->igmp_cksum = in_cksum(m, IGMP_MINLEN);
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m->m_data -= sizeof(struct ip);
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m->m_len += sizeof(struct ip);
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ip = mtod(m, struct ip *);
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ip->ip_tos = 0;
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ip->ip_len = sizeof(struct ip) + IGMP_MINLEN;
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ip->ip_off = 0;
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ip->ip_p = IPPROTO_IGMP;
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ip->ip_src.s_addr = INADDR_ANY;
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ip->ip_dst.s_addr = addr ? addr : igmp->igmp_group.s_addr;
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imo.imo_multicast_ifp = inm->inm_ifp;
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imo.imo_multicast_ttl = 1;
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imo.imo_multicast_vif = -1;
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/*
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* Request loopback of the report if we are acting as a multicast
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* router, so that the process-level routing demon can hear it.
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*/
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imo.imo_multicast_loop = (ip_mrouter != NULL);
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/*
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* XXX
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* Do we have to worry about reentrancy here? Don't think so.
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*/
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ip_output(m, router_alert, &igmprt, 0, &imo);
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++igmpstat.igps_snd_reports;
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}
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