igmp_proto.c

/*
 * Copyright (c) 1998-2001
 * University of Southern California/Information Sciences Institute.
 * All rights reserved.
 *
 * 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. Neither the name of the project 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 PROJECT 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 PROJECT 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.
 */
/*
 *  $Id: igmp_proto.c,v 1.15 2001/09/10 20:31:36 pavlin Exp $
 */
/*
 * Part of this program has been derived from mrouted.
 * The mrouted program is covered by the license in the accompanying file
 * named "LICENSE.mrouted".
 *
 * The mrouted program is COPYRIGHT 1989 by The Board of Trustees of
 * Leland Stanford Junior University.
 *
 */

#include "defs.h"

typedef struct {
    vifi_t  vifi;
    struct listaddr *g;
    int    q_time;
} cbk_t;


/*
 * Forward declarations.
 */
static void DelVif       (void *arg);
static int SetTimer      (vifi_t vifi, struct listaddr *g);
static int DeleteTimer   (int id);
static void send_query   (struct uvif *v, uint32_t group, int interval);
static void SendQuery    (void *arg);
static int SetQueryTimer (struct listaddr *g, vifi_t vifi, int to_expire, int q_time);
static uint32_t igmp_group_membership_timeout(void);

/* The querier timeout depends on the configured query interval */
uint32_t default_igmp_query_interval  = IGMP_QUERY_INTERVAL;
uint32_t default_igmp_querier_timeout = IGMP_OTHER_QUERIER_PRESENT_INTERVAL;


/*
 * Send group membership queries on that interface if I am querier.
 */
void query_groups(struct uvif *v)
{
    struct listaddr *g;

    v->uv_gq_timer = default_igmp_query_interval;
    send_query(v, allhosts_group, (v->uv_flags & VIFF_IGMPV1)
	       ? 0 : IGMP_MAX_HOST_REPORT_DELAY * IGMP_TIMER_SCALE);

    /*
     * Decrement the old-hosts-present timer for each
     * active group on that vif.
     */
    for (g = v->uv_groups; g != NULL; g = g->al_next) {
	if (g->al_old > TIMER_INTERVAL)
	    g->al_old -= TIMER_INTERVAL;
	else
	    g->al_old = 0;
    }
}


/*
 * Process an incoming host membership query
 */
void accept_membership_query(uint32_t src, uint32_t dst __attribute__((unused)), uint32_t group, int tmo)
{
    vifi_t vifi;
    struct uvif *v;

    /* Ignore my own membership query */
    if (local_address(src) != NO_VIF)
	return;

    /* TODO: modify for DVMRP?? */
    if ((vifi = find_vif_direct(src)) == NO_VIF) {
	IF_DEBUG(DEBUG_IGMP)
	    logit(LOG_INFO, 0,
		  "ignoring group membership query from non-adjacent host %s",
		  inet_fmt(src, s1, sizeof(s1)));
	return;
    }

    v = &uvifs[vifi];

    if ((tmo == 0 && !(v->uv_flags & VIFF_IGMPV1)) ||
	(tmo != 0 &&  (v->uv_flags & VIFF_IGMPV1))) {
	int i;

	/*
	 * Exponentially back-off warning rate
	 */
	i = ++v->uv_igmpv1_warn;
	while (i && !(i & 1))
	    i >>= 1;
	if (i == 1) {
	    logit(LOG_WARNING, 0, "%s %s on vif %d, %s",
		  tmo == 0
		  ? "Received IGMPv1 report from"
		  : "Received IGMPv2 report from",
		  inet_fmt(src, s1, sizeof(s1)),
		  vifi,
		  tmo == 0
		  ? "please configure vif for IGMPv1"
		  : "but I am configured for IGMPv1");
	}
    }

    if (v->uv_querier == NULL || v->uv_querier->al_addr != src) {
	/*
	 * This might be:
	 * - A query from a new querier, with a lower source address
	 *   than the current querier (who might be me)
	 * - A query from a new router that just started up and doesn't
	 *   know who the querier is.
	 * - A query from the current querier
	 */
	if (ntohl(src) < (v->uv_querier ? ntohl(v->uv_querier->al_addr)
			  : ntohl(v->uv_lcl_addr))) {
	    IF_DEBUG(DEBUG_IGMP)
		logit(LOG_DEBUG, 0, "new querier %s (was %s) on vif %d",
		      inet_fmt(src, s1, sizeof(s1)),
		      v->uv_querier
		      ? inet_fmt(v->uv_querier->al_addr, s2, sizeof(s2))
		      : "me", vifi);
	    if (!v->uv_querier) {
		v->uv_querier = (struct listaddr *) calloc(1, sizeof(struct listaddr));
		if (!v->uv_querier) {
		    logit(LOG_ERR, 0, "Failed calloc() in accept_membership_query()");
		    return;
		}

		v->uv_querier->al_next = (struct listaddr *)NULL;
		v->uv_querier->al_timer = 0;
		v->uv_querier->al_genid = 0;
		/* TODO: write the protocol version */
		v->uv_querier->al_pv = 0;
		v->uv_querier->al_mv = 0;
		v->uv_querier->al_old = 0;
		v->uv_querier->al_index = 0;
		v->uv_querier->al_timerid = 0;
		v->uv_querier->al_query = 0;
		v->uv_querier->al_flags = 0;

		v->uv_flags &= ~VIFF_QUERIER;
	    }
	    v->uv_querier->al_addr = src;
	    time(&v->uv_querier->al_ctime);
	}
    }

    /*
     * Reset the timer since we've received a query.
     */
    if (v->uv_querier && src == v->uv_querier->al_addr)
	v->uv_querier->al_timer = 0;

    /*
     * If this is a Group-Specific query which we did not source,
     * we must set our membership timer to [Last Member Query Count] *
     * the [Max Response Time] in the packet.
     */
    if (!(v->uv_flags & VIFF_IGMPV1) && group != 0 &&
	src != v->uv_lcl_addr) {
	struct listaddr *g;

	IF_DEBUG(DEBUG_IGMP) {
	    logit(LOG_DEBUG, 0,
		  "%s for %s from %s on vif %d, timer %d",
		  "Group-specific membership query",
		  inet_fmt(group, s2, sizeof(s2)), inet_fmt(src, s1, sizeof(s1)), vifi, tmo);
	}

	for (g = v->uv_groups; g != NULL; g = g->al_next) {
	    if (group == g->al_addr && g->al_query == 0) {
		/* setup a timeout to remove the group membership */
		if (g->al_timerid)
		    g->al_timerid = DeleteTimer(g->al_timerid);
		g->al_timer = IGMP_LAST_MEMBER_QUERY_COUNT * tmo / IGMP_TIMER_SCALE;
		/* use al_query to record our presence in last-member state */
		g->al_query = -1;
		g->al_timerid = SetTimer(vifi, g);
		IF_DEBUG(DEBUG_IGMP) {
		    logit(LOG_DEBUG, 0,
			  "timer for grp %s on vif %d set to %ld",
			  inet_fmt(group, s2, sizeof(s2)), vifi, g->al_timer);
		}
		break;
	    }
	}
    }
}


/*
 * Process an incoming group membership report.
 */
void accept_group_report(uint32_t src, uint32_t dst __attribute__((unused)), uint32_t group, int igmp_report_type)
{
    vifi_t vifi;
    struct uvif *v;
    struct listaddr *g;

    if ((vifi = find_vif_direct_local(src)) == NO_VIF) {
	IF_DEBUG(DEBUG_IGMP) {
	    logit(LOG_INFO, 0,
		  "ignoring group membership report from non-adjacent host %s",
		  inet_fmt(src, s1, sizeof(s1)));
	}
	return;
    }

    v = &uvifs[vifi];

    /*
     * Look for the group in our group list; if found, reset its timer.
     */
    for (g = v->uv_groups; g != NULL; g = g->al_next) {
	if (group == g->al_addr) {
	    if (igmp_report_type == IGMP_V1_MEMBERSHIP_REPORT)
		g->al_old = DVMRP_OLD_AGE_THRESHOLD;

	    g->al_reporter = src;

	    /** delete old timers, set a timer for expiration **/
	    g->al_timer = igmp_group_membership_timeout ();
	    if (g->al_query)
		g->al_query = DeleteTimer(g->al_query);
	    if (g->al_timerid)
		g->al_timerid = DeleteTimer(g->al_timerid);
	    g->al_timerid = SetTimer(vifi, g);
	    /* TODO: might need to add a check if I am the forwarder??? */
	    /* if (v->uv_flags & VIFF_DR) */
	    add_leaf(vifi, INADDR_ANY_N, group);
	    break;
	}
    }

    /*
     * If not found, add it to the list and update kernel cache.
     */
    if (g == NULL) {
	g = (struct listaddr *)calloc(1, sizeof(struct listaddr));
	if (!g) {
	    logit(LOG_ERR, 0, "Ran out of memory");    /* fatal */
	    return;
	}

	g->al_addr   = group;
	if (igmp_report_type == IGMP_V1_MEMBERSHIP_REPORT)
	    g->al_old = DVMRP_OLD_AGE_THRESHOLD;
	else
	    g->al_old = 0;

	/** set a timer for expiration **/
	g->al_query     = 0;
	g->al_timer     = igmp_group_membership_timeout ();
	g->al_reporter  = src;
	g->al_timerid   = SetTimer(vifi, g);
	g->al_next      = v->uv_groups;
	v->uv_groups    = g;
	time(&g->al_ctime);

	/* TODO: might need to add a check if I am the forwarder??? */
	/* if (v->uv_flags & VIFF_DR) */
	add_leaf(vifi, INADDR_ANY_N, group);
    }
}


/* TODO: send PIM prune message if the last member? */
void accept_leave_message(uint32_t src, uint32_t dst __attribute__((unused)), uint32_t group)
{
    vifi_t vifi;
    struct uvif *v;
    struct listaddr *g;

    /* TODO: modify for DVMRP ??? */
    if ((vifi = find_vif_direct_local(src)) == NO_VIF) {
	IF_DEBUG(DEBUG_IGMP) {
	    logit(LOG_INFO, 0, "ignoring group leave report from non-adjacent host %s",
		  inet_fmt(src, s1, sizeof(s1)));
	}
	return;
    }

    v = &uvifs[vifi];

#if 0
    /* XXX: a PIM-SM last-hop router needs to know when a local member
     * has left.
     */
    if (!(v->uv_flags & (VIFF_QUERIER | VIFF_DR))
	|| (v->uv_flags & VIFF_IGMPV1))
	return;
#endif

    /*
     * Look for the group in our group list in order to set up a short-timeout
     * query.
     */
    for (g = v->uv_groups; g != NULL; g = g->al_next) {
	if (group == g->al_addr) {
	    IF_DEBUG(DEBUG_IGMP)
		logit(LOG_DEBUG, 0, "accept_leave_message(): %d %d", g->al_old, g->al_query);

	    /* Ignore the leave message if there are old hosts present */
	    if (g->al_old)
		return;

	    /* still waiting for a reply to a query, ignore the leave */
	    if (g->al_query)
		return;

	    /** delete old timer set a timer for expiration **/
	    if (g->al_timerid)
		g->al_timerid = DeleteTimer(g->al_timerid);

#if IGMP_LAST_MEMBER_QUERY_COUNT != 2
/*
  This code needs to be updated to keep a counter of the number
  of queries remaining.
*/
#endif
	    /** send a group specific querry **/
	    send_query(v, g->al_addr, IGMP_LAST_MEMBER_QUERY_INTERVAL * IGMP_TIMER_SCALE);

	    g->al_timer = IGMP_LAST_MEMBER_QUERY_INTERVAL * (IGMP_LAST_MEMBER_QUERY_COUNT + 1);
	    g->al_query = SetQueryTimer(g, vifi,
					IGMP_LAST_MEMBER_QUERY_INTERVAL,
					IGMP_LAST_MEMBER_QUERY_INTERVAL * IGMP_TIMER_SCALE);
	    g->al_timerid = SetTimer(vifi, g);
	    break;
	}
    }
}

/*
 * Handle IGMP v3 membership reports (join/leave)
 */
void accept_membership_report(uint32_t src, uint32_t dst, struct igmp_report *report)
{
    size_t i, numgrp = ntohs(report->ir_numgrps);
    uint32_t group;
    struct igmp_grouprec *grec;

    IF_DEBUG(DEBUG_IGMP)
	logit(LOG_DEBUG, 0, "IGMP v3 report from %s with %u group records",
	      inet_fmt(src, s1, sizeof(s1)), numgrp);

    grec = (struct igmp_grouprec *)((char *)report + IGMP_V3_REPORT_MINLEN);
    for (i = 0; i < numgrp; i++) {
	uint8_t type = grec->ig_type;
	size_t numsrc = ntohs(grec->ig_numsrc);

	/* Keep it in big endian, network byte order */
	group = grec->ig_group.s_addr;

	IF_DEBUG(DEBUG_IGMP)
	    logit(LOG_DEBUG, 0, "               group %s type %d num_src %u",
		  inet_fmt(group, s1, sizeof(s1)), type, numsrc);

	switch (type) {
	    case IGMP_MODE_IS_EXCLUDE:
	    case IGMP_CHANGE_TO_EXCLUDE_MODE:
		accept_group_report(src, dst, group, IGMP_V3_MEMBERSHIP_REPORT);
		break;

	    case IGMP_CHANGE_TO_INCLUDE_MODE:
		accept_leave_message(src, dst, group);
		break;

	    default:
		/* Nothing to do */
		break;
	}

	/* Adjust for optional number of ig_sources[] */
	grec = (struct igmp_grouprec *)((char *)grec +
					IGMP_GRPREC_HDRLEN +
					numsrc * sizeof(struct in_addr));
    }
}

/*
 * Calculate group membership timeout
 */
static uint32_t igmp_group_membership_timeout(void)
{
    return IGMP_ROBUSTNESS_VARIABLE * default_igmp_query_interval
	+ IGMP_QUERY_RESPONSE_INTERVAL;
}

/*
 * Time out record of a group membership on a vif
 */
static void DelVif(void *arg)
{
    cbk_t *cbk = (cbk_t *)arg;
    vifi_t vifi = cbk->vifi;
    struct uvif *v = &uvifs[vifi];
    struct listaddr *a, **anp, *g = cbk->g;

    /*
     * Group has expired
     * delete all kernel cache entries with this group
     */
    if (g->al_query)
	DeleteTimer(g->al_query);

    delete_leaf(vifi, INADDR_ANY_N, g->al_addr);

    anp = &(v->uv_groups);
    while ((a = *anp) != NULL) {
	if (a == g) {
	    *anp = a->al_next;
	    free((char *)a);
	} else {
	    anp = &a->al_next;
	}
    }

    free(cbk);
}


/*
 * Set a timer to delete the record of a group membership on a vif.
 */
static int SetTimer(vifi_t vifi, struct listaddr *g)
{
    cbk_t *cbk;

    cbk = (cbk_t *) calloc(1, sizeof(cbk_t));
    if (!cbk) {
	logit(LOG_ERR, 0, "Failed calloc() in SetTimer()");
	return -1;
    }

    cbk->vifi = vifi;
    cbk->g = g;

    return timer_setTimer(g->al_timer, DelVif, cbk);
}


/*
 * Delete a timer that was set above.
 */
static int DeleteTimer(int id)
{
    timer_clearTimer(id);

    return 0;
}


/*
 * Send IGMP Query
 */
static void send_query(struct uvif *v, uint32_t group, int interval)
{
    if (v->uv_flags & VIFF_QUERIER) {
	send_igmp(igmp_send_buf, v->uv_lcl_addr, group,
		  IGMP_MEMBERSHIP_QUERY, interval, group != allhosts_group ? group : 0, 0);
    }
}

/*
 * Send a group-specific query.
 */
static void SendQuery(void *arg)
{
    cbk_t *cbk = (cbk_t *)arg;

    send_query(&uvifs[cbk->vifi], cbk->g->al_addr, cbk->q_time);
    cbk->g->al_query = 0;
    free(cbk);
}


/*
 * Set a timer to send a group-specific query.
 */
static int SetQueryTimer(struct listaddr *g, vifi_t vifi, int to_expire, int q_time)
{
    cbk_t *cbk;

    cbk = (cbk_t *)calloc(1, sizeof(cbk_t));
    if (!cbk) {
	logit(LOG_ERR, 0, "Failed calloc() in SetQueryTimer()");
	return -1;
    }

    cbk->g = g;
    cbk->q_time = q_time;
    cbk->vifi = vifi;

    return timer_setTimer(to_expire, SendQuery, cbk);
}

/**
 * Local Variables:
 *  version-control: t
 *  indent-tabs-mode: t
 *  c-file-style: "ellemtel"
 *  c-basic-offset: 4
 * End:
 */