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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

 * $Id: igmp.c,v 1.2 2001-09-27 12:01:55 chris Exp $

 */

/*

 * 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.

 * Modified to fully comply to IGMPv2 by Bill Fenner, Oct 1995.

 *

 * MULTICAST Revision: 3.5.1.4

 */

#include <sys/param.h>

#include <sys/systm.h>

#include <sys/mbuf.h>

#include <sys/socket.h>

#include <sys/protosw.h>

#include <sys/kernel.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>

static struct router_info *

                find_rti __P((struct ifnet *ifp));

static struct igmpstat igmpstat;

SYSCTL_STRUCT(_net_inet_igmp, IGMPCTL_STATS, stats, CTLFLAG_RD,

        &igmpstat, igmpstat, "");

static int igmp_timers_are_running;

static u_long igmp_all_hosts_group;

static u_long igmp_all_rtrs_group;

static struct mbuf *router_alert;

static struct router_info *Head;

static void igmp_sendpkt(struct in_multi *, int, unsigned long);

void

igmp_init()

{

        struct ipoption *ra;

        /*

         * To avoid byte-swapping the same value over and over again.

         */

        igmp_all_hosts_group = htonl(INADDR_ALLHOSTS_GROUP);

        igmp_all_rtrs_group = htonl(INADDR_ALLRTRS_GROUP);

        igmp_timers_are_running = 0;

        /*

         * Construct a Router Alert option to use in outgoing packets

         */

        MGET(router_alert, M_DONTWAIT, MT_DATA);

        ra = mtod(router_alert, struct ipoption *);

        ra->ipopt_dst.s_addr = 0;

        ra->ipopt_list[0] = IPOPT_RA;    /* Router Alert Option */

        ra->ipopt_list[1] = 0x04;       /* 4 bytes long */

        ra->ipopt_list[2] = 0x00;

        ra->ipopt_list[3] = 0x00;

        router_alert->m_len = sizeof(ra->ipopt_dst) + ra->ipopt_list[1];

        Head = (struct router_info *) 0;

}

static 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->rti_ifp == ifp) {

#ifdef IGMP_DEBUG

                        printf("[igmp.c, _find_rti] --> found old entry \n");

#endif

                        return rti;

                }

                rti = rti->rti_next;

        }

        MALLOC(rti, struct router_info *, sizeof *rti, M_MRTABLE, M_NOWAIT);

        rti->rti_ifp = ifp;

        rti->rti_type = IGMP_V2_ROUTER;

        rti->rti_time = 0;

        rti->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);

        /*

         * In the IGMPv2 specification, there are 3 states and a flag.

         *

         * In Non-Member state, we simply don't have a membership record.

         * In Delaying Member state, our timer is running (inm->inm_timer)

         * In Idle Member state, our timer is not running (inm->inm_timer==0)

         *

         * The flag is inm->inm_state, it is set to IGMP_OTHERMEMBER if

         * we have heard a report from another member, or IGMP_IREPORTEDLAST

         * if I sent the last report.

         */

        switch (igmp->igmp_type) {

        case IGMP_MEMBERSHIP_QUERY:

                ++igmpstat.igps_rcv_queries;

                if (ifp->if_flags & IFF_LOOPBACK)

                        break;

                if (igmp->igmp_code == 0) {

                        /*

                         * Old router.  Remember that the querier on this

                         * interface is old, and set the timer to the

                         * value in RFC 1112.

                         */

                        rti->rti_type = IGMP_V1_ROUTER;

                        rti->rti_time = 0;

                        timer = IGMP_MAX_HOST_REPORT_DELAY * PR_FASTHZ;

                        if (ip->ip_dst.s_addr != igmp_all_hosts_group ||

                            igmp->igmp_group.s_addr != 0) {

                                ++igmpstat.igps_rcv_badqueries;

                                m_freem(m);

                                return;

                        }

                } else {

                        /*

                         * New router.  Simply do the new validity check.

                         */

                        if (igmp->igmp_group.s_addr != 0 &&

                            !IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) {

                                ++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 the "all-hosts" group (224.0.0.1).

                 * - Restart any timer that is already running but has

                 *   a value longer than the requested timeout.

                 * - Use the value specified in the query message as

                 *   the maximum timeout.

                 */

                IN_FIRST_MULTI(step, inm);

                while (inm != NULL) {

                        if (inm->inm_ifp == ifp &&

                            inm->inm_addr.s_addr != igmp_all_hosts_group &&

                            (igmp->igmp_group.s_addr == 0 ||

                             igmp->igmp_group.s_addr == inm->inm_addr.s_addr)) {

                                if (inm->inm_timer == 0 ||

                                    inm->inm_timer > timer) {

                                        inm->inm_timer =

                                                IGMP_RANDOM_DELAY(timer);

                                        igmp_timers_are_running = 1;

                                }

                        }

                        IN_NEXT_MULTI(step, inm);

                }

                break;

        case IGMP_V1_MEMBERSHIP_REPORT:

        case IGMP_V2_MEMBERSHIP_REPORT:

                /*

                 * For fast leave to work, we have to know that we are the

                 * last person to send a report for this group.  Reports

                 * can potentially get looped back if we are a multicast

                 * router, so discard reports sourced by me.

                 */

                IFP_TO_IA(ifp, ia);

                if (ia && ip->ip_src.s_addr == IA_SIN(ia)->sin_addr.s_addr)

                        break;

                ++igmpstat.igps_rcv_reports;

                if (ifp->if_flags & IFF_LOOPBACK)

                        break;

                if (!IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) {

                        ++igmpstat.igps_rcv_badreports;

                        m_freem(m);

                        return;

                }

                /*

                 * KLUDGE: if the IP source address of the report has an

                 * unspecified (i.e., zero) subnet number, as is allowed for

                 * a booting host, replace it with the correct subnet number

                 * so that a process-level multicast routing demon can

                 * determine which subnet it arrived from.  This is necessary

                 * to compensate for the lack of any way for a process to

                 * determine the arrival interface of an incoming packet.

                 */

                if ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) == 0)

                        if (ia) ip->ip_src.s_addr = htonl(ia->ia_subnet);

                /*

                 * If we belong to the group being reported, stop

                 * our timer for that group.

                 */

                IN_LOOKUP_MULTI(igmp->igmp_group, ifp, inm);

                if (inm != NULL) {

                        inm->inm_timer = 0;

                        ++igmpstat.igps_rcv_ourreports;

                        inm->inm_state = IGMP_OTHERMEMBER;

                }

                break;

        }

        /*

         * Pass all valid IGMP packets up to any process(es) listening

         * on a raw IGMP socket.

         */

        rip_input(m, iphlen);

}

void

igmp_joingroup(inm)

        struct in_multi *inm;

{

        int s = splnet();

        if (inm->inm_addr.s_addr == igmp_all_hosts_group

            || inm->inm_ifp->if_flags & IFF_LOOPBACK) {

                inm->inm_timer = 0;

                inm->inm_state = IGMP_OTHERMEMBER;

        } else {

                inm->inm_rti = find_rti(inm->inm_ifp);

                igmp_sendpkt(inm, inm->inm_rti->rti_type, 0);

                inm->inm_timer = IGMP_RANDOM_DELAY(

                                        IGMP_MAX_HOST_REPORT_DELAY*PR_FASTHZ);

                inm->inm_state = IGMP_IREPORTEDLAST;

                igmp_timers_are_running = 1;

        }

        splx(s);

}

void

igmp_leavegroup(inm)

        struct in_multi *inm;

{

        if (inm->inm_state == IGMP_IREPORTEDLAST &&

            inm->inm_addr.s_addr != igmp_all_hosts_group &&

            !(inm->inm_ifp->if_flags & IFF_LOOPBACK) &&

            inm->inm_rti->rti_type != IGMP_V1_ROUTER)

                igmp_sendpkt(inm, IGMP_V2_LEAVE_GROUP, igmp_all_rtrs_group);

}

void

igmp_fasttimo()

{

        register struct in_multi *inm;

        struct in_multistep step;

        int s;

        /*

         * Quick check to see if any work needs to be done, in order

         * to minimize the overhead of fasttimo processing.

         */

        if (!igmp_timers_are_running)

                return;

        s = splnet();

        igmp_timers_are_running = 0;

        IN_FIRST_MULTI(step, inm);

        while (inm != NULL) {

                if (inm->inm_timer == 0) {

                        /* do nothing */

                } else if (--inm->inm_timer == 0) {

                        igmp_sendpkt(inm, inm->inm_rti->rti_type, 0);

                        inm->inm_state = IGMP_IREPORTEDLAST;

                } else {

                        igmp_timers_are_running = 1;

                }

                IN_NEXT_MULTI(step, inm);

        }

        splx(s);

}

void

igmp_slowtimo()

{

        int s = splnet();

        register struct router_info *rti =  Head;

#ifdef IGMP_DEBUG

        printf("[igmp.c,_slowtimo] -- > entering \n");

#endif

        while (rti) {

            if (rti->rti_type == IGMP_V1_ROUTER) {

                rti->rti_time++;

                if (rti->rti_time >= IGMP_AGE_THRESHOLD) {

                        rti->rti_type = IGMP_V2_ROUTER;

                }

            }

            rti = rti->rti_next;

        }

#ifdef IGMP_DEBUG       

        printf("[igmp.c,_slowtimo] -- > exiting \n");

#endif

        splx(s);

}

static struct route igmprt;

static void

igmp_sendpkt(inm, type, addr)

        struct in_multi *inm;

        int type;

        unsigned long addr;

{

        struct mbuf *m;

        struct igmp *igmp;

        struct ip *ip;

        struct ip_moptions imo;

        MGETHDR(m, M_DONTWAIT, MT_HEADER);

        if (m == NULL)

                return;

        m->m_pkthdr.rcvif = loif;

        m->m_pkthdr.len = sizeof(struct ip) + IGMP_MINLEN;

        MH_ALIGN(m, IGMP_MINLEN + sizeof(struct ip));

        m->m_data += sizeof(struct ip);

        m->m_len = IGMP_MINLEN;

        igmp = mtod(m, struct igmp *);

        igmp->igmp_type   = type;

        igmp->igmp_code   = 0;

        igmp->igmp_group  = inm->inm_addr;

        igmp->igmp_cksum  = 0;

        igmp->igmp_cksum  = in_cksum(m, IGMP_MINLEN);

        m->m_data -= sizeof(struct ip);

        m->m_len += sizeof(struct ip);

        ip = mtod(m, struct ip *);

        ip->ip_tos        = 0;

        ip->ip_len        = sizeof(struct ip) + IGMP_MINLEN;

        ip->ip_off        = 0;

        ip->ip_p          = IPPROTO_IGMP;

        ip->ip_src.s_addr = INADDR_ANY;

        ip->ip_dst.s_addr = addr ? addr : igmp->igmp_group.s_addr;

        imo.imo_multicast_ifp  = inm->inm_ifp;

        imo.imo_multicast_ttl  = 1;

        imo.imo_multicast_vif  = -1;

        /*

         * Request loopback of the report if we are acting as a multicast

         * router, so that the process-level routing demon can hear it.

         */

        imo.imo_multicast_loop = (ip_mrouter != NULL);

        /*

         * XXX

         * Do we have to worry about reentrancy here?  Don't think so.

         */

        ip_output(m, router_alert, &igmprt, 0, &imo);

        ++igmpstat.igps_snd_reports;

}