314 lines
7.8 KiB
C
314 lines
7.8 KiB
C
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/*
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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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*/
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/* Internet Group Management Protocol (IGMP) routines. */
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#include <sys/param.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 <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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extern struct ifnet loif;
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static int igmp_timers_are_running = 0;
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static u_long igmp_all_hosts_group;
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static void igmp_sendreport __P((struct in_multi *));
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void
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igmp_init()
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{
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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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}
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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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++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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switch (igmp->igmp_type) {
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case IGMP_HOST_MEMBERSHIP_QUERY:
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++igmpstat.igps_rcv_queries;
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if (ifp == &loif)
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break;
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if (ip->ip_dst.s_addr != igmp_all_hosts_group) {
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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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* Start the timers in all of our membership records for
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* the interface on which the query arrived, except those
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* that are already running and those that belong to the
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* "all-hosts" group.
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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 && inm->inm_timer == 0 &&
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inm->inm_addr.s_addr != igmp_all_hosts_group) {
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inm->inm_timer =
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IGMP_RANDOM_DELAY(inm->inm_addr);
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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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break;
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case IGMP_HOST_MEMBERSHIP_REPORT:
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++igmpstat.igps_rcv_reports;
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if (ifp == &loif)
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break;
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if (!IN_MULTICAST(ntohl(igmp->igmp_group.s_addr)) ||
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igmp->igmp_group.s_addr != ip->ip_dst.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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IFP_TO_IA(ifp, ia);
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if (ia) ip->ip_src.s_addr = htonl(ia->ia_subnet);
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}
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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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}
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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);
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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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register int s = splnet();
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if (inm->inm_addr.s_addr == igmp_all_hosts_group ||
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inm->inm_ifp == &loif)
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inm->inm_timer = 0;
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else {
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igmp_sendreport(inm);
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inm->inm_timer = IGMP_RANDOM_DELAY(inm->inm_addr);
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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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/*
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* No action required on leaving a group.
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*/
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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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register int s;
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struct in_multistep step;
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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_sendreport(inm);
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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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static void
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igmp_sendreport(inm)
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register struct in_multi *inm;
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{
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register struct mbuf *m;
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register struct igmp *igmp;
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register struct ip *ip;
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register struct ip_moptions *imo;
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struct ip_moptions simo;
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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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/*
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* Assume max_linkhdr + sizeof(struct ip) + IGMP_MINLEN
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* is smaller than mbuf size returned by MGETHDR.
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*/
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m->m_data += max_linkhdr;
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m->m_len = sizeof(struct ip) + IGMP_MINLEN;
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m->m_pkthdr.len = sizeof(struct ip) + IGMP_MINLEN;
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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 = inm->inm_addr;
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igmp = (struct igmp *)(ip + 1);
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igmp->igmp_type = IGMP_HOST_MEMBERSHIP_REPORT;
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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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imo = &simo;
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bzero((caddr_t)imo, sizeof(*imo));
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imo->imo_multicast_ifp = inm->inm_ifp;
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imo->imo_multicast_ttl = 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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#ifdef MROUTING
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{
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extern struct socket *ip_mrouter;
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imo->imo_multicast_loop = (ip_mrouter != NULL);
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}
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#endif
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ip_output(m, NULL, NULL, 0, imo);
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++igmpstat.igps_snd_reports;
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}
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