igmp.c

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/*
 * Copyright (c) 1988 Stephen Deering.
 * Copyright (c) 1992, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Stephen Deering of Stanford University.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	@(#)igmp.c	8.1 (Berkeley) 7/19/93
 */

/*
 * Internet Group Management Protocol (IGMP) routines.
 *
 * Written by Steve Deering, Stanford, May 1988.
 * Modified by Rosen Sharma, Stanford, Aug 1994.
 * Modified by Bill Fenner, Xerox PARC, Feb 1995.
 *
 * MULTICAST Revision: 3.3.1.2
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/protosw.h>
#include <sys/proc.h>		/* XXX needed for sysctl.h */
#include <vm/vm.h>		/* XXX needed for sysctl.h */
#include <sys/sysctl.h>

#include <net/if.h>
#include <net/route.h>

#include <netinet/in.h>
#include <netinet/in_var.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#include <netinet/igmp.h>
#include <netinet/igmp_var.h>

struct igmpstat igmpstat;

static int igmp_timers_are_running;
static u_long igmp_all_hosts_group;
static u_long igmp_local_group;
static u_long igmp_local_group_mask;
static struct router_info *Head;

static void igmp_sendpkt(struct in_multi *, int);
static void igmp_sendleave(struct in_multi *);

void
igmp_init()
{
	/*
	 * To avoid byte-swapping the same value over and over again.
	 */
	igmp_all_hosts_group = htonl(INADDR_ALLHOSTS_GROUP);
	igmp_local_group = htonl(0xe0000000);		/* 224.0.0.0 */
	igmp_local_group_mask = htonl(0xffffff00);	/* ........^ */

	igmp_timers_are_running = 0;

	Head = (struct router_info *) 0;
}

int
fill_rti(inm)
	struct in_multi *inm;
{
	register struct router_info *rti = Head;

#ifdef IGMP_DEBUG
	printf("[igmp.c, _fill_rti] --> entering \n");
#endif
	while (rti) {
		if (rti->ifp == inm->inm_ifp) {
			inm->inm_rti  = rti;
#ifdef IGMP_DEBUG
			printf("[igmp.c, _fill_rti] --> found old entry \n");
#endif
			if (rti->type == IGMP_OLD_ROUTER) 
				return IGMP_HOST_MEMBERSHIP_REPORT;
			else
				return IGMP_HOST_NEW_MEMBERSHIP_REPORT;
		}
		rti = rti->next;
	}
	MALLOC(rti, struct router_info *, sizeof *rti, M_MRTABLE, M_NOWAIT);
	rti->ifp = inm->inm_ifp;
	rti->type = IGMP_NEW_ROUTER;
	rti->time = IGMP_AGE_THRESHOLD;
	rti->next = Head;
	Head = rti;	
	inm->inm_rti = rti;
#ifdef IGMP_DEBUG
	printf("[igmp.c, _fill_rti] --> created new entry \n");
#endif
	return IGMP_HOST_NEW_MEMBERSHIP_REPORT;
}

struct router_info *
find_rti(ifp)
	struct ifnet *ifp;
{
        register struct router_info *rti = Head;

#ifdef IGMP_DEBUG
	printf("[igmp.c, _find_rti] --> entering \n");
#endif
        while (rti) {
                if (rti->ifp == ifp) {
#ifdef IGMP_DEBUG
			printf("[igmp.c, _find_rti] --> found old entry \n");
#endif
                        return rti;
                }
                rti = rti->next;
        }
	MALLOC(rti, struct router_info *, sizeof *rti, M_MRTABLE, M_NOWAIT);
        rti->ifp = ifp;
        rti->type = IGMP_NEW_ROUTER;
        rti->time = IGMP_AGE_THRESHOLD;
        rti->next = Head;
        Head = rti;
#ifdef IGMP_DEBUG
	printf("[igmp.c, _find_rti] --> created an entry \n");
#endif
        return rti;
}

void
igmp_input(m, iphlen)
	register struct mbuf *m;
	register int iphlen;
{
	register struct igmp *igmp;
	register struct ip *ip;
	register int igmplen;
	register struct ifnet *ifp = m->m_pkthdr.rcvif;
	register int minlen;
	register struct in_multi *inm;
	register struct in_ifaddr *ia;
	struct in_multistep step;
	struct router_info *rti;
	
	int timer; /** timer value in the igmp query header **/

	++igmpstat.igps_rcv_total;

	ip = mtod(m, struct ip *);
	igmplen = ip->ip_len;

	/*
	 * Validate lengths
	 */
	if (igmplen < IGMP_MINLEN) {
		++igmpstat.igps_rcv_tooshort;
		m_freem(m);
		return;
	}
	minlen = iphlen + IGMP_MINLEN;
	if ((m->m_flags & M_EXT || m->m_len < minlen) &&
	    (m = m_pullup(m, minlen)) == 0) {
		++igmpstat.igps_rcv_tooshort;
		return;
	}

	/*
	 * Validate checksum
	 */
	m->m_data += iphlen;
	m->m_len -= iphlen;
	igmp = mtod(m, struct igmp *);
	if (in_cksum(m, igmplen)) {
		++igmpstat.igps_rcv_badsum;
		m_freem(m);
		return;
	}
	m->m_data -= iphlen;
	m->m_len += iphlen;

	ip = mtod(m, struct ip *);
	timer = igmp->igmp_code * PR_FASTHZ / IGMP_TIMER_SCALE;
	rti = find_rti(ifp);

	switch (igmp->igmp_type) {

	case IGMP_HOST_MEMBERSHIP_QUERY:
		++igmpstat.igps_rcv_queries;

		if (ifp->if_flags & IFF_LOOPBACK)
			break;

		if (igmp->igmp_code == 0) {

			rti->type = IGMP_OLD_ROUTER; rti->time = 0;

			/*
			** Do exactly as RFC 1112 says
			*/

			if (ip->ip_dst.s_addr != igmp_all_hosts_group) {
				++igmpstat.igps_rcv_badqueries;
				m_freem(m);
				return;
			}

			/*
			 * Start the timers in all of our membership records for
			 * the interface on which the query arrived, except those
			 * that are  already running and those that belong to a
			 * "local" group (224.0.0.X).
			 */
			IN_FIRST_MULTI(step, inm);
			while (inm != NULL) {
				if (inm->inm_ifp == ifp 
				    && inm->inm_timer == 0
				    && ((inm->inm_addr.s_addr 
					 & igmp_local_group_mask) 
					!= igmp_local_group)) {

					inm->inm_state = IGMP_DELAYING_MEMBER;
					inm->inm_timer = IGMP_RANDOM_DELAY(
				IGMP_MAX_HOST_REPORT_DELAY * PR_FASTHZ );

					igmp_timers_are_running = 1;
				}
				IN_NEXT_MULTI(step, inm);
			}
		} else {
		    /*
		    ** New Router
		    */
		    
		    if (!(m->m_flags & M_MCAST)) {
			++igmpstat.igps_rcv_badqueries;
			m_freem(m);
			return;
		    }
		    
		    /*
		     * - Start the timers in all of our membership records
		     *   that the query applies to for the interface on
		     *   which the query arrived excl. those that belong
		     *   to a "local" group (224.0.0.X)
		     * - For timers already running check if they need to
		     *   be reset.
		     * - Use the igmp->igmp_code field as the maximum 
		     *   delay possible
		     */
		    IN_FIRST_MULTI(step, inm);
		    while (inm != NULL) {
			if (inm->inm_ifp == ifp &&
			    (inm->inm_addr.s_addr & igmp_local_group_mask) !=
				igmp_local_group &&
			    (ip->ip_dst.s_addr == igmp_all_hosts_group ||
			     ip->ip_dst.s_addr == inm->inm_addr.s_addr)) {
			    switch(inm->inm_state) {
			      case IGMP_IDLE_MEMBER:
			      case IGMP_LAZY_MEMBER:
			      case IGMP_AWAKENING_MEMBER:
				    inm->inm_timer = IGMP_RANDOM_DELAY(timer);
				    igmp_timers_are_running = 1;
				    inm->inm_state = IGMP_DELAYING_MEMBER;
				    break;
			      case IGMP_DELAYING_MEMBER:
				if (inm->inm_timer > timer) {
				    inm->inm_timer = IGMP_RANDOM_DELAY(timer);
				    igmp_timers_are_running = 1;
				    inm->inm_state = IGMP_DELAYING_MEMBER;
				}
				break;
			      case IGMP_SLEEPING_MEMBER:
				inm->inm_state = IGMP_AWAKENING_MEMBER;
				break;
			    }
			}
			IN_NEXT_MULTI(step, inm);
		}
	    }

		break;

	case IGMP_HOST_MEMBERSHIP_REPORT: