fsck_msdosfs: check next cluster index for validity before using it

[dragonfly.git] / usr.sbin / mrouted / prune.c

/*
 * The mrouted program is covered by the license in the accompanying file
 * named "LICENSE".  Use of the mrouted program represents acceptance of
 * the terms and conditions listed in that file.
 *
 * The mrouted program is COPYRIGHT 1989 by The Board of Trustees of
 * Leland Stanford Junior University.
 *
 *
 * prune.c,v 3.8.4.59 1998/03/01 02:06:32 fenner Exp
 *
 * $FreeBSD: src/usr.sbin/mrouted/prune.c,v 1.17.2.1 2000/10/29 03:59:57 kris Exp $
 * $DragonFly: src/usr.sbin/mrouted/prune.c,v 1.6 2008/04/20 13:44:26 swildner Exp $
 */

#include "defs.h"

extern int cache_lifetime;
extern int prune_lifetime;
extern struct rtentry *routing_table;

extern int phys_vif;

extern int allow_black_holes;

/*
 * randomize value to obtain a value between .5x and 1.5x
 * in order to prevent synchronization
 */
#ifdef SYSV
#define JITTERED_VALUE(x) ((x)/2 + (lrand48() % (x)))
#else
#define JITTERED_VALUE(x) ((x)/2 + (arc4random() % (x)))
#endif
#define CACHE_LIFETIME(x)       JITTERED_VALUE(x) /* XXX */

struct gtable *kernel_table;            /* ptr to list of kernel grp entries*/
static struct gtable *kernel_no_route;  /* list of grp entries w/o routes   */
struct gtable *gtp;                     /* pointer for kernel rt entries    */
unsigned int kroutes;                   /* current number of cache entries  */

/****************************************************************************
                       Functions that are local to prune.c
****************************************************************************/
static int              scoped_addr(vifi_t vifi, u_int32 addr);
static void             prun_add_ttls(struct gtable *gt);
static int              pruning_neighbor(vifi_t vifi, u_int32 addr);
static int              can_mtrace(vifi_t vifi, u_int32 addr);
static struct ptable *  find_prune_entry(u_int32 vr, struct ptable *pt);
static void             remove_sources(struct gtable *gt);
static void             rexmit_prune(void *arg);
static void             expire_prune(vifi_t vifi, struct gtable *gt);
static void             send_prune(struct gtable *gt);
static void             send_graft(struct gtable *gt);
static void             send_graft_ack(u_int32 src, u_int32 dst,
                                        u_int32 origin, u_int32 grp,
                                        vifi_t vifi);
static void             update_kernel(struct gtable *g);

/* 
 * Updates the ttl values for each vif.
 */
static void
prun_add_ttls(struct gtable *gt)
{
    struct uvif *v;
    vifi_t vifi;
    
    for (vifi = 0, v = uvifs; vifi < numvifs; ++vifi, ++v) {
        if (VIFM_ISSET(vifi, gt->gt_grpmems))
            gt->gt_ttls[vifi] = v->uv_threshold;
        else 
            gt->gt_ttls[vifi] = 0;
    }
}

/*
 * checks for scoped multicast addresses
 * XXX I want to make the check of allow_black_holes based on ALLOW_BLACK_HOLES
 * but macros are not functions.
 */
#define GET_SCOPE(gt) {                                                 \
        vifi_t _i;                                                      \
                                                                        \
        VIFM_CLRALL((gt)->gt_scope);                                    \
        if (allow_black_holes ||                                        \
            (ntohl((gt)->gt_mcastgrp) & 0xff000000) == 0xef000000)      \
            for (_i = 0; _i < numvifs; _i++)                            \
                if (scoped_addr(_i, (gt)->gt_mcastgrp))                 \
                    VIFM_SET(_i, (gt)->gt_scope);                       \
        }                                                               \
        if ((gt)->gt_route == NULL || ((gt)->gt_route->rt_parent != NO_VIF && \
            VIFM_ISSET((gt)->gt_route->rt_parent, (gt)->gt_scope)))     \
                VIFM_SETALL((gt)->gt_scope);

#define APPLY_SCOPE(gt) VIFM_CLR_MASK((gt)->gt_grpmems, (gt)->gt_scope)

#define GET_MEMBERSHIP(gt, vifi) {                                      \
        if ((gt)->gt_route &&                                           \
            VIFM_ISSET((vifi), (gt)->gt_route->rt_children) &&          \
            (!SUBS_ARE_PRUNED((gt)->gt_route->rt_subordinates,          \
                                uvifs[vifi].uv_nbrmap, (gt)->gt_prunes) || \
             grplst_mem((vifi), (gt)->gt_mcastgrp)))                    \
                VIFM_SET((vifi), (gt)->gt_grpmems);                     \
        }

static int
scoped_addr(vifi_t vifi, u_int32 addr)
{
    struct vif_acl *acl;

    for (acl = uvifs[vifi].uv_acl; acl; acl = acl->acl_next)
        if ((addr & acl->acl_mask) == acl->acl_addr)
            return 1;

    return 0;
}

/*
 * Determine the list of outgoing vifs, based upon
 * route subordinates, prunes received, and group
 * memberships.
 */
void
determine_forwvifs(struct gtable *gt)
{
    vifi_t i;

    VIFM_CLRALL(gt->gt_grpmems);
    for (i = 0; i < numvifs; i++) {
        GET_MEMBERSHIP(gt, i);
    }
    GET_SCOPE(gt);
    APPLY_SCOPE(gt);
}

/*
 * Send a prune or a graft if necessary.
 */
void
send_prune_or_graft(struct gtable *gt)
{
    if (VIFM_ISEMPTY(gt->gt_grpmems))
        send_prune(gt);
    else if (gt->gt_prsent_timer)
        send_graft(gt);
}

/* 
 * Determine if mcastgrp has a listener on vifi
 */
int
grplst_mem(vifi_t vifi, u_int32 mcastgrp)
{
    struct listaddr *g;
    struct uvif *v;
    
    v = &uvifs[vifi];
    
    for (g = v->uv_groups; g != NULL; g = g->al_next)
        if (mcastgrp == g->al_addr) 
            return 1;
    
    return 0;
}

/*
 * Finds the group entry with the specified source and netmask.
 * If netmask is 0, it uses the route's netmask.
 *
 * Returns TRUE if found a match, and the global variable gtp is left
 * pointing to entry before the found entry.
 * Returns FALSE if no exact match found, gtp is left pointing to before
 * the entry in question belongs, or is NULL if the it belongs at the
 * head of the list.
 */
int
find_src_grp(u_int32 src, u_int32 mask, u_int32 grp)
{
    struct gtable *gt;

    gtp = NULL;
    gt = kernel_table;
    while (gt != NULL) {
        if (grp == gt->gt_mcastgrp &&
            (mask ? (gt->gt_route->rt_origin == src &&
                     gt->gt_route->rt_originmask == mask) :
                    ((src & gt->gt_route->rt_originmask) ==
                     gt->gt_route->rt_origin)))
            return TRUE;
        if (ntohl(grp) > ntohl(gt->gt_mcastgrp) ||
            (grp == gt->gt_mcastgrp &&
             (ntohl(mask) < ntohl(gt->gt_route->rt_originmask) ||
              (mask == gt->gt_route->rt_originmask &&
               (ntohl(src) > ntohl(gt->gt_route->rt_origin)))))) {
            gtp = gt;
            gt = gt->gt_gnext;
        }
        else break;
    }
    return FALSE;
}

/*
 * Check if the neighbor supports pruning
 */
static int
pruning_neighbor(vifi_t vifi, u_int32 addr)
{
    struct listaddr *n = neighbor_info(vifi, addr);
    int vers;

    if (n == NULL)
        return 0;

    vers = NBR_VERS(n);
    return (vers >= 0x0300 && ((vers & 0xff00) != 0x0a00));
}

/*
 * Can the neighbor in question handle multicast traceroute?
 */
static int
can_mtrace(vifi_t vifi, u_int32 addr)
{
    struct listaddr *n = neighbor_info(vifi, addr);
    int vers;

    if (n == NULL)
        return 1;       /* fail "safe" */

    vers = NBR_VERS(n);
    return (vers >= 0x0303 && ((vers & 0xff00) != 0x0a00));
}

/*
 * Returns the prune entry of the router, or NULL if none exists
 */
static struct ptable *
find_prune_entry(u_int32 vr, struct ptable *pt)
{
    while (pt) {
        if (pt->pt_router == vr)
            return pt;
        pt = pt->pt_next;
    }

    return NULL;
}

/*
 * Remove all the sources hanging off the group table entry from the kernel
 * cache.  Remember the packet counts wherever possible, to keep the mtrace
 * counters consistent.  This prepares for possible prune retransmission,
 * either on a multi-access network or when a prune that we sent upstream
 * has expired.
 */
static void
remove_sources(struct gtable *gt)
{
    struct stable *st;
    struct sioc_sg_req sg_req;

    sg_req.grp.s_addr = gt->gt_mcastgrp;

    /*
     * call k_del_rg() on every one of the gt->gt_srctbl entries
     * but first save the packet count so that the mtrace packet
     * counters can remain approximately correct.  There's a race
     * here but it's minor.
     */
    for (st = gt->gt_srctbl; st; st = st->st_next) {
        if (st->st_ctime == 0)
            continue;
        IF_DEBUG(DEBUG_PRUNE)
        log(LOG_DEBUG, 0, "rexmit_prune deleting (%s %s) (next is %d sec)",
                inet_fmt(st->st_origin, s1),
                inet_fmt(gt->gt_mcastgrp, s2),
                gt->gt_prune_rexmit);
        sg_req.src.s_addr = st->st_origin;
        if (ioctl(udp_socket, SIOCGETSGCNT, (char *)&sg_req) < 0) {
            sg_req.pktcnt = 0;
        }
        k_del_rg(st->st_origin, gt);
        st->st_ctime = 0;       /* flag that it's not in the kernel any more */
        st->st_savpkt += sg_req.pktcnt;
        kroutes--;
    }

    /*
     * Now, add_table_entry will prune when asked to add a cache entry.
     */
}

/*
 * Prepare for possible prune retransmission
 */
static void
rexmit_prune(void *arg)
{
    struct gtable *gt = *(struct gtable **)arg;

    free(arg);

    gt->gt_rexmit_timer = 0;

    /* Make sure we're still not forwarding traffic */
    if (!VIFM_ISEMPTY(gt->gt_grpmems)) {
        IF_DEBUG(DEBUG_PRUNE)
        log(LOG_DEBUG, 0, "rexmit_prune (%s %s): gm:%x",
                RT_FMT(gt->gt_route, s1), inet_fmt(gt->gt_mcastgrp, s2),
                gt->gt_grpmems);
        return;
    }

    remove_sources(gt);
}

/*
 * Send a prune message to the dominant router for
 * this source.
 *
 * Record an entry that a prune was sent for this group
 */
static void
send_prune(struct gtable *gt)
{
    struct ptable *pt;
    char *p;
    int i;
    int datalen;
    u_int32 dst;
    u_int32 tmp;
    int rexmitting = 0;
    struct uvif *v;
    
    /*
     * Can't process a prune if we don't have an associated route
     * or if the route points to a local interface.
     */
    if (gt->gt_route == NULL || gt->gt_route->rt_parent == NO_VIF ||
                gt->gt_route->rt_gateway == 0)
        return;

    /* Don't send a prune to a non-pruning router */
    if (!pruning_neighbor(gt->gt_route->rt_parent, gt->gt_route->rt_gateway))
        return;
    
    v = &uvifs[gt->gt_route->rt_parent];
    /* 
     * sends a prune message to the router upstream.
     */
#if 0
    dst = v->uv_flags & VIFF_TUNNEL ? dvmrp_group : gt->gt_route->rt_gateway; /*XXX*/
#else
    dst = gt->gt_route->rt_gateway;
#endif
    
    p = send_buf + MIN_IP_HEADER_LEN + IGMP_MINLEN;
    datalen = 0;
    
    /*
     * determine prune lifetime, if this isn't a retransmission.
     *
     * Use interface-specified lifetime if there is one.
     */
    if (gt->gt_prsent_timer == 0) {
        int l = prune_lifetime;

        if (v->uv_prune_lifetime != 0)
            l = v->uv_prune_lifetime;

        gt->gt_prsent_timer = JITTERED_VALUE(l);
        for (pt = gt->gt_pruntbl; pt; pt = pt->pt_next)
            if (pt->pt_timer < gt->gt_prsent_timer)
                gt->gt_prsent_timer = pt->pt_timer;
    } else if (gt->gt_prsent_timer < 0) {
        IF_DEBUG(DEBUG_PRUNE)
        log(LOG_DEBUG, 0, "asked to rexmit? (%s,%s)/%d on vif %d to %s with negative time",
            RT_FMT(gt->gt_route, s1), inet_fmt(gt->gt_mcastgrp, s2),
            gt->gt_prsent_timer, gt->gt_route->rt_parent,
            inet_fmt(gt->gt_route->rt_gateway, s3));
        return;
    } else
        rexmitting = 1;

    if (rexmitting && !(v->uv_flags & VIFF_REXMIT_PRUNES)) {
        IF_DEBUG(DEBUG_PRUNE)
        log(LOG_DEBUG, 0, "not rexmitting prune for (%s %s)/%d on vif %d to %s",
            RT_FMT(gt->gt_route, s1), inet_fmt(gt->gt_mcastgrp, s2),
            gt->gt_prsent_timer, gt->gt_route->rt_parent,
            inet_fmt(gt->gt_route->rt_gateway, s3));
        return;
    }
    if (gt->gt_prsent_timer <= MIN_PRUNE_LIFE) {
        IF_DEBUG(DEBUG_PRUNE)
        log(LOG_DEBUG, 0, "not bothering to send prune for (%s,%s)/%d on vif %d to %s because it's too short",
            RT_FMT(gt->gt_route, s1), inet_fmt(gt->gt_mcastgrp, s2),
            gt->gt_prsent_timer, gt->gt_route->rt_parent,
            inet_fmt(gt->gt_route->rt_gateway, s3));
        return;
    }
    
    /*
     * If we have a graft pending, cancel graft retransmission
     */
    gt->gt_grftsnt = 0;

    for (i = 0; i < 4; i++)
        *p++ = ((char *)&(gt->gt_route->rt_origin))[i];
    for (i = 0; i < 4; i++)
        *p++ = ((char *)&(gt->gt_mcastgrp))[i];
    tmp = htonl(gt->gt_prsent_timer);
    for (i = 0; i < 4; i++)
        *p++ = ((char *)&(tmp))[i];
    datalen += 12;
    
    send_on_vif(v, dst, DVMRP_PRUNE, datalen);
    
    IF_DEBUG(DEBUG_PRUNE)
    log(LOG_DEBUG, 0, "%s prune for (%s %s)/%d on vif %d to %s",
      rexmitting ? "rexmitted" : "sent",
      RT_FMT(gt->gt_route, s1), inet_fmt(gt->gt_mcastgrp, s2),
      gt->gt_prsent_timer, gt->gt_route->rt_parent,
      inet_fmt(gt->gt_route->rt_gateway, s3));

    if ((v->uv_flags & VIFF_REXMIT_PRUNES) &&
        gt->gt_rexmit_timer == 0 &&
        gt->gt_prsent_timer > gt->gt_prune_rexmit) {
        struct gtable **arg =
                    (struct gtable **)malloc(sizeof (struct gtable **));

        *arg = gt;
        gt->gt_rexmit_timer = timer_setTimer(
                                        JITTERED_VALUE(gt->gt_prune_rexmit),
                                        rexmit_prune, arg);
        gt->gt_prune_rexmit *= 2;
    }
}

/*
 * a prune was sent upstream
 * so, a graft has to be sent to annul the prune
 * set up a graft timer so that if an ack is not 
 * heard within that time, another graft request
 * is sent out.
 */
static void
send_graft(struct gtable *gt)
{
    char *p;
    int i;
    int datalen;
    u_int32 dst;

    /* Can't send a graft without an associated route */
    if (gt->gt_route == NULL || gt->gt_route->rt_parent == NO_VIF) {
        gt->gt_grftsnt = 0;
        return;
    }

    gt->gt_prsent_timer = 0;
    gt->gt_prune_rexmit = PRUNE_REXMIT_VAL;
    if (gt->gt_rexmit_timer)
        timer_clearTimer(gt->gt_rexmit_timer);

    if (gt->gt_grftsnt == 0)
        gt->gt_grftsnt = 1;

#if 0
    dst = uvifs[gt->gt_route->rt_parent].uv_flags & VIFF_TUNNEL ? dvmrp_group : gt->gt_route->rt_gateway; /*XXX*/
#else
    dst = gt->gt_route->rt_gateway;
#endif

    p = send_buf + MIN_IP_HEADER_LEN + IGMP_MINLEN;
    datalen = 0;
    
    for (i = 0; i < 4; i++)
        *p++ = ((char *)&(gt->gt_route->rt_origin))[i];
    for (i = 0; i < 4; i++)
        *p++ = ((char *)&(gt->gt_mcastgrp))[i];
    datalen += 8;
    
    send_on_vif(&uvifs[gt->gt_route->rt_parent], dst, DVMRP_GRAFT, datalen);
    IF_DEBUG(DEBUG_PRUNE)
    log(LOG_DEBUG, 0, "sent graft for (%s %s) to %s on vif %d",
        RT_FMT(gt->gt_route, s1), inet_fmt(gt->gt_mcastgrp, s2),
        inet_fmt(gt->gt_route->rt_gateway, s3), gt->gt_route->rt_parent);
}

/*
 * Send an ack that a graft was received
 */
static void
send_graft_ack(u_int32 src, u_int32 dst, u_int32 origin, u_int32 grp,
               vifi_t vifi)
{
    char *p;
    int i;
    int datalen;

    p = send_buf + MIN_IP_HEADER_LEN + IGMP_MINLEN;
    datalen = 0;
    
    for (i = 0; i < 4; i++)
        *p++ = ((char *)&(origin))[i];
    for (i = 0; i < 4; i++)
        *p++ = ((char *)&(grp))[i];
    datalen += 8;
    
    if (vifi == NO_VIF)
        send_igmp(src, dst, IGMP_DVMRP, DVMRP_GRAFT_ACK,
                  htonl(MROUTED_LEVEL), datalen);
    else {
#if 0
        if (uvifs[vifi].uv_flags & VIFF_TUNNEL)
            dst = dvmrp_group;  /* XXX */
#endif
        send_on_vif(&uvifs[vifi], dst, DVMRP_GRAFT_ACK, datalen);
    }

    IF_DEBUG(DEBUG_PRUNE)
    if (vifi == NO_VIF)
        log(LOG_DEBUG, 0, "sent graft ack for (%s, %s) to %s",
            inet_fmt(origin, s1), inet_fmt(grp, s2), inet_fmt(dst, s3));
    else
        log(LOG_DEBUG, 0, "sent graft ack for (%s, %s) to %s on vif %d",
            inet_fmt(origin, s1), inet_fmt(grp, s2), inet_fmt(dst, s3), vifi);
}

/*
 * Update the kernel cache with all the routes hanging off the group entry
 */
static void
update_kernel(struct gtable *g)
{
    struct stable *st;

    for (st = g->gt_srctbl; st; st = st->st_next)
        if (st->st_ctime != 0)
            k_add_rg(st->st_origin, g);
}

/****************************************************************************
                          Functions that are used externally
****************************************************************************/

#ifdef SNMP
#include <sys/types.h>
#include "snmp.h"

/*
 * Find a specific group entry in the group table
 */
struct gtable *
find_grp(u_int32 grp)
{
   struct gtable *gt;

   for (gt = kernel_table; gt; gt = gt->gt_gnext) {
      if (ntohl(grp) < ntohl(gt->gt_mcastgrp))
         break;
      if (gt->gt_mcastgrp == grp) 
         return gt;
   }
   return NULL;
}

/*
 * Given a group entry and source, find the corresponding source table
 * entry
 */
struct stable *
find_grp_src(struct gtable *gt, u_int32 src)
{
   struct stable *st;
   u_long grp = gt->gt_mcastgrp;
   struct gtable *gtcurr;

   for (gtcurr = gt; gtcurr->gt_mcastgrp == grp; gtcurr = gtcurr->gt_gnext) {
      for (st = gtcurr->gt_srctbl; st; st = st->st_next)
         if (st->st_origin == src)
            return st;
   }
   return NULL;
}

/* 
 * Find next entry > specification 
 */
int
next_grp_src_mask(struct gtable **gtpp, /* ordered by group  */
                  struct stable **stpp, /* ordered by source */
                  u_int32 grp, u_int32 src, u_int32 mask)
{
   struct gtable *gt, *gbest = NULL;
   struct stable *st, *sbest = NULL;

   /* Find first group entry >= grp spec */
   (*gtpp) = kernel_table;
   while ((*gtpp) && ntohl((*gtpp)->gt_mcastgrp) < ntohl(grp))
      (*gtpp)=(*gtpp)->gt_gnext;
   if (!(*gtpp)) 
      return 0; /* no more groups */
   
   for (gt = kernel_table; gt; gt=gt->gt_gnext) {
      /* Since grps are ordered, we can stop when group changes from gbest */
      if (gbest && gbest->gt_mcastgrp != gt->gt_mcastgrp)
         break;
      for (st = gt->gt_srctbl; st; st=st->st_next) {

         /* Among those entries > spec, find "lowest" one */
         if (((ntohl(gt->gt_mcastgrp)> ntohl(grp))
           || (ntohl(gt->gt_mcastgrp)==ntohl(grp) 
              && ntohl(st->st_origin)> ntohl(src))
           || (ntohl(gt->gt_mcastgrp)==ntohl(grp) 
              && ntohl(st->st_origin)==src && 0xFFFFFFFF>ntohl(mask)))
          && (!gbest 
           || (ntohl(gt->gt_mcastgrp)< ntohl(gbest->gt_mcastgrp))
           || (ntohl(gt->gt_mcastgrp)==ntohl(gbest->gt_mcastgrp) 
              && ntohl(st->st_origin)< ntohl(sbest->st_origin)))) {
               gbest = gt;
               sbest = st;
         }
      }
   }
   (*gtpp) = gbest;
   (*stpp) = sbest;
   return (*gtpp)!=0;
}

/*
 * Ensure that sg contains current information for the given group,source.
 * This is fetched from the kernel as a unit so that counts for the entry 
 * are consistent, i.e. packet and byte counts for the same entry are 
 * read at the same time.
 */
void
refresh_sg(struct sioc_sg_req *sg, struct gtable *gt, struct stable *st)
{
   static   int lastq = -1;

   if (quantum != lastq || sg->src.s_addr!=st->st_origin
    || sg->grp.s_addr!=gt->gt_mcastgrp) {
       lastq = quantum;
       sg->src.s_addr = st->st_origin;
       sg->grp.s_addr = gt->gt_mcastgrp;
       ioctl(udp_socket, SIOCGETSGCNT, (char *)sg);
   }
}

/*
 * Given a routing table entry, and a vifi, find the next entry
 * equal to or greater than those
 */
int
next_child(struct gtable **gtpp, struct stable **stpp,
           u_int32 grp, u_int32 src, u_int32 mask,
           vifi_t vifi) /* vif at which to start looking */
{

   /* Get (G,S,M) entry */
   if (mask!=0xFFFFFFFF
    || !((*gtpp) = find_grp(grp))
    || !((*stpp) = find_grp_src((*gtpp),src)))
      if (!next_grp_src_mask(gtpp, stpp, grp, src, mask))
         return 0;

   /* Continue until we get one with a valid next vif */
   do {
      for (; (*gtpp)->gt_route->rt_children && *vifi<numvifs; (*vifi)++)
         if (VIFM_ISSET(*vifi, (*gtpp)->gt_route->rt_children))
            return 1;
      *vifi = 0;
   } while (next_grp_src_mask(gtpp, stpp, (*gtpp)->gt_mcastgrp, 
                (*stpp)->st_origin, 0xFFFFFFFF) );

   return 0;
}
#endif /* SNMP */

/*
 * Initialize the kernel table structure
 */
void
init_ktable(void)
{
    kernel_table        = NULL;
    kernel_no_route     = NULL;
    kroutes             = 0;
}

/* 
 * Add a new table entry for (origin, mcastgrp)
 */
void
add_table_entry(u_int32 origin, u_int32 mcastgrp)
{
    struct rtentry *r;
    struct gtable *gt,**gtnp,*prev_gt;
    struct stable *st,**stnp;

    /*
     * Since we have to enable mrouting to get the version number,
     * some cache creation requests can sneak through.  Ignore them
     * since we're not going to do useful stuff until we've performed
     * final initialization.
     */
    if (!did_final_init)
        return;

#ifdef DEBUG_MFC
    md_log(MD_MISS, origin, mcastgrp);
#endif
    
    r = determine_route(origin);
    prev_gt = NULL;
    if (r == NULL) {
        /*
         * Look for it on the no_route table; if it is found then
         * it will be detected as a duplicate below.
         */
        for (gt = kernel_no_route; gt; gt = gt->gt_next)
            if (mcastgrp == gt->gt_mcastgrp &&
                gt->gt_srctbl && gt->gt_srctbl->st_origin == origin)
                        break;
        gtnp = &kernel_no_route;
    } else {
        gtnp = &r->rt_groups;
        while ((gt = *gtnp) != NULL) {
            if (gt->gt_mcastgrp >= mcastgrp)
                break;
            gtnp = &gt->gt_next;
            prev_gt = gt;
        }
    }

    if (gt == NULL || gt->gt_mcastgrp != mcastgrp) {
        gt = (struct gtable *)malloc(sizeof(struct gtable));
        if (gt == NULL)
            log(LOG_ERR, 0, "ran out of memory");

        gt->gt_mcastgrp     = mcastgrp;
        gt->gt_timer        = CACHE_LIFETIME(cache_lifetime);
        time(&gt->gt_ctime);
        gt->gt_prsent_timer = 0;
        gt->gt_grftsnt      = 0;
        gt->gt_srctbl       = NULL;
        gt->gt_pruntbl      = NULL;
        gt->gt_route        = r;
        gt->gt_rexmit_timer = 0;
        NBRM_CLRALL(gt->gt_prunes);
        gt->gt_prune_rexmit = PRUNE_REXMIT_VAL;
#ifdef RSRR
        gt->gt_rsrr_cache   = NULL;
#endif

        /* Calculate forwarding vifs */
        determine_forwvifs(gt);

        /* update ttls */
        prun_add_ttls(gt);

        gt->gt_next = *gtnp;
        *gtnp = gt;
        if (gt->gt_next)
            gt->gt_next->gt_prev = gt;
        gt->gt_prev = prev_gt;

        if (r) {
            if (find_src_grp(r->rt_origin, r->rt_originmask, gt->gt_mcastgrp)) {
                struct gtable *g;

                g = gtp ? gtp->gt_gnext : kernel_table;
                log(LOG_WARNING, 0, "Entry for (%s %s) (rt:%x) exists (rt:%x)",
                    RT_FMT(r, s1), inet_fmt(g->gt_mcastgrp, s2),
                    r, g->gt_route);
            } else {
                if (gtp) {
                    gt->gt_gnext = gtp->gt_gnext;
                    gt->gt_gprev = gtp;
                    gtp->gt_gnext = gt;
                } else {
                    gt->gt_gnext = kernel_table;
                    gt->gt_gprev = NULL;
                    kernel_table = gt;
                }
                if (gt->gt_gnext)
                    gt->gt_gnext->gt_gprev = gt;
            }
        } else {
            gt->gt_gnext = gt->gt_gprev = NULL;
        }
    }

    stnp = &gt->gt_srctbl;
    while ((st = *stnp) != NULL) {
        if (ntohl(st->st_origin) >= ntohl(origin))
            break;
        stnp = &st->st_next;
    }

    if (st == NULL || st->st_origin != origin) {
        st = (struct stable *)malloc(sizeof(struct stable));
        if (st == NULL)
            log(LOG_ERR, 0, "ran out of memory");

        st->st_origin = origin;
        st->st_pktcnt = 0;
        st->st_savpkt = 0;
        time(&st->st_ctime);
        st->st_next = *stnp;
        *stnp = st;
    } else {
        if (st->st_ctime == 0) {
            /* An old source which we're keeping around for statistics */
            time(&st->st_ctime);
        } else {
#ifdef DEBUG_MFC
            md_log(MD_DUPE, origin, mcastgrp);
#endif
            /* Ignore kernel->mrouted retransmissions */
            if (time(0) - st->st_ctime > 5)
                log(LOG_WARNING, 0, "kernel entry already exists for (%s %s)",
                        inet_fmt(origin, s1), inet_fmt(mcastgrp, s2));
            k_add_rg(origin, gt);
            return;
        }
    }

    kroutes++;
    k_add_rg(origin, gt);

    IF_DEBUG(DEBUG_CACHE)
    log(LOG_DEBUG, 0, "add cache entry (%s %s) gm:%x, parent-vif:%d",
        inet_fmt(origin, s1),
        inet_fmt(mcastgrp, s2),
        gt->gt_grpmems, r ? r->rt_parent : -1);

    /*
     * If there are no downstream routers that want traffic for
     * this group, send (or retransmit) a prune upstream.
     */
    if (VIFM_ISEMPTY(gt->gt_grpmems))
        send_prune(gt);
}

/*
 * A router has gone down.  Remove prune state pertinent to that router.
 */
void
reset_neighbor_state(vifi_t vifi, u_int32 addr)
{
    struct rtentry *r;
    struct gtable *g;
    struct ptable *pt, **ptnp;
    struct stable *st;
    
    for (g = kernel_table; g; g = g->gt_gnext) {
        r = g->gt_route;

        /*
         * If neighbor was the parent, remove the prune sent state
         * and all of the source cache info so that prunes get
         * regenerated.
         */
        if (vifi == r->rt_parent) {
            if (addr == r->rt_gateway) {
                IF_DEBUG(DEBUG_PEER)
                log(LOG_DEBUG, 0, "reset_neighbor_state parent reset (%s %s)",
                    RT_FMT(r, s1), inet_fmt(g->gt_mcastgrp, s2));

                g->gt_prsent_timer = 0;
                g->gt_grftsnt = 0;
                while ((st = g->gt_srctbl) != NULL) {
                    g->gt_srctbl = st->st_next;
                    if (st->st_ctime != 0) {
                        k_del_rg(st->st_origin, g);
                        kroutes--;
                    }
                    free(st);
                }
            }
        } else {
            /*
             * Remove any prunes that this router has sent us.
             */
            ptnp = &g->gt_pruntbl;
            while ((pt = *ptnp) != NULL) {
                if (pt->pt_vifi == vifi && pt->pt_router == addr) {
                    NBRM_CLR(pt->pt_index, g->gt_prunes);
                    *ptnp = pt->pt_next;
                    free(pt);
                } else
                    ptnp = &pt->pt_next;
            }

            /*
             * And see if we want to forward again.
             */
            if (!VIFM_ISSET(vifi, g->gt_grpmems)) {
                GET_MEMBERSHIP(g, vifi);
                APPLY_SCOPE(g);
                prun_add_ttls(g);

                /* Update kernel state */
                update_kernel(g);
#ifdef RSRR
                /* Send route change notification to reservation protocol. */
                rsrr_cache_send(g,1);
#endif /* RSRR */

                /*
                 * If removing this prune causes us to start forwarding
                 * (e.g. the neighbor rebooted), and we sent a prune upstream,
                 * send a graft to cancel the prune.
                 */
                if (!VIFM_ISEMPTY(g->gt_grpmems) && g->gt_prsent_timer)
                    send_graft(g);

                IF_DEBUG(DEBUG_PEER)
                log(LOG_DEBUG, 0, "reset neighbor state (%s %s) gm:%x",
                    RT_FMT(r, s1),
                    inet_fmt(g->gt_mcastgrp, s2), g->gt_grpmems);
            }
        }
    }
}

/*
 * Delete table entry from the kernel
 * del_flag determines how many entries to delete
 */
void
del_table_entry(struct rtentry *r, u_int32 mcastgrp, u_int del_flag)
{
    struct gtable *g, *prev_g;
    struct stable *st, *prev_st;
    struct ptable *pt, *prev_pt;
    
    if (del_flag == DEL_ALL_ROUTES) {
        g = r->rt_groups;
        while (g) {
            IF_DEBUG(DEBUG_CACHE)
            log(LOG_DEBUG, 0, "del_table_entry deleting (%s %s)",
                RT_FMT(r, s1), inet_fmt(g->gt_mcastgrp, s2));
            st = g->gt_srctbl;
            while (st) {
                if (st->st_ctime != 0) {
                    if (k_del_rg(st->st_origin, g) < 0) {
                        log(LOG_WARNING, errno,
                            "del_table_entry trying to delete (%s, %s)",
                            inet_fmt(st->st_origin, s1),
                            inet_fmt(g->gt_mcastgrp, s2));
                    }
                    kroutes--;
                }
                prev_st = st;
                st = st->st_next;
                free(prev_st);
            }
            g->gt_srctbl = NULL;

            pt = g->gt_pruntbl;
            while (pt) {
                prev_pt = pt;
                pt = pt->pt_next;
                free(prev_pt);
            }
            g->gt_pruntbl = NULL;

            if (g->gt_gnext)
                g->gt_gnext->gt_gprev = g->gt_gprev;
            if (g->gt_gprev)
                g->gt_gprev->gt_gnext = g->gt_gnext;
            else
                kernel_table = g->gt_gnext;

#ifdef RSRR
            /* Send route change notification to reservation protocol. */
            rsrr_cache_send(g,0);
            rsrr_cache_clean(g);
#endif /* RSRR */
            if (g->gt_rexmit_timer)
                timer_clearTimer(g->gt_rexmit_timer);

            prev_g = g;
            g = g->gt_next;
            free(prev_g);
        }
        r->rt_groups = NULL;
    }
    
    /* 
     * Dummy routine - someday this may be needed, so it is just there
     */
    if (del_flag == DEL_RTE_GROUP) {
        prev_g = (struct gtable *)&r->rt_groups;
        for (g = r->rt_groups; g; g = g->gt_next) {
            if (g->gt_mcastgrp == mcastgrp) {
                IF_DEBUG(DEBUG_CACHE)
                log(LOG_DEBUG, 0, "del_table_entry deleting (%s %s)",
                    RT_FMT(r, s1), inet_fmt(g->gt_mcastgrp, s2));
                st = g->gt_srctbl;
                while (st) {
                    if (st->st_ctime != 0) {
                        if (k_del_rg(st->st_origin, g) < 0) {
                            log(LOG_WARNING, errno,
                                "del_table_entry trying to delete (%s, %s)",
                                inet_fmt(st->st_origin, s1),
                                inet_fmt(g->gt_mcastgrp, s2));
                        }
                        kroutes--;
                    }
                    prev_st = st;
                    st = st->st_next;
                    free(prev_st);
                }
                g->gt_srctbl = NULL;

                pt = g->gt_pruntbl;
                while (pt) {
                    prev_pt = pt;
                    pt = pt->pt_next;
                    free(prev_pt);
                }
                g->gt_pruntbl = NULL;

                if (g->gt_gnext)
                    g->gt_gnext->gt_gprev = g->gt_gprev;
                if (g->gt_gprev)
                    g->gt_gprev->gt_gnext = g->gt_gnext;
                else
                    kernel_table = g->gt_gnext;

                if (prev_g != (struct gtable *)&r->rt_groups)
                    g->gt_next->gt_prev = prev_g;
                else
                    g->gt_next->gt_prev = NULL;
                prev_g->gt_next = g->gt_next;

                if (g->gt_rexmit_timer)
                    timer_clearTimer(g->gt_rexmit_timer);
#ifdef RSRR
                /* Send route change notification to reservation protocol. */
                rsrr_cache_send(g,0);
                rsrr_cache_clean(g);
#endif /* RSRR */
                free(g);
                g = prev_g;
            } else {
                prev_g = g;
            }
        }
    }
}

/*
 * update kernel table entry when a route entry changes
 */
void
update_table_entry(struct rtentry *r, u_int32 old_parent_gw)
{
    struct gtable *g;
    struct ptable *pt, **ptnp;

    for (g = r->rt_groups; g; g = g->gt_next) {
        ptnp = &g->gt_pruntbl;
        /*
         * Delete prune entries from non-children, or non-subordinates.
         */
        while ((pt = *ptnp)) {
            if (!VIFM_ISSET(pt->pt_vifi, r->rt_children) ||
                !NBRM_ISSET(pt->pt_index, r->rt_subordinates)) {

                IF_DEBUG(DEBUG_PRUNE)
                log(LOG_DEBUG, 0, "update_table_entry deleting prune for (%s %s) from %s on vif %d -%s%s",
                        RT_FMT(r, s1), inet_fmt(g->gt_mcastgrp, s2),
                        inet_fmt(pt->pt_router, s3), pt->pt_vifi,
                        VIFM_ISSET(pt->pt_vifi, r->rt_children) ? "" : " not a child",
                        NBRM_ISSET(pt->pt_index, r->rt_subordinates) ? "" : " not a subordinate");

                if (!NBRM_ISSET(pt->pt_index, g->gt_prunes)) {
                    log(LOG_WARNING, 0,
                        "gt_prunes lost track of (%s %s) from %s on vif %d",
                        RT_FMT(r, s1), inet_fmt(g->gt_mcastgrp, s2),
                        inet_fmt(pt->pt_router, s3), pt->pt_vifi);
                }

                NBRM_CLR(pt->pt_index, g->gt_prunes);
                *ptnp = pt->pt_next;
                free(pt);
                continue;
            }
            ptnp = &((*ptnp)->pt_next);
        }

        IF_DEBUG(DEBUG_CACHE)
        log(LOG_DEBUG, 0, "updating cache entries (%s %s) old gm:%x",
            RT_FMT(r, s1), inet_fmt(g->gt_mcastgrp, s2),
            g->gt_grpmems);

        /*
         * Forget about a prune or graft that we sent previously if we
         * have a new parent router (since the new parent router will
         * know nothing about what I sent to the previous parent).  The
         * old parent will forget any prune state it is keeping for us.
         */
        if (old_parent_gw != r->rt_gateway) {
            g->gt_prsent_timer = 0;
            g->gt_grftsnt = 0;
        }

        /* Recalculate membership */
        determine_forwvifs(g);
        /* send a prune or graft if needed. */
        send_prune_or_graft(g);

        IF_DEBUG(DEBUG_CACHE)
        log(LOG_DEBUG, 0, "updating cache entries (%s %s) new gm:%x",
            RT_FMT(r, s1), inet_fmt(g->gt_mcastgrp, s2),
            g->gt_grpmems);

        /* update ttls and add entry into kernel */
        prun_add_ttls(g);
        update_kernel(g);
#ifdef RSRR
        /* Send route change notification to reservation protocol. */
        rsrr_cache_send(g,1);
#endif /* RSRR */
    }
}

/*
 * set the forwarding flag for all mcastgrps on this vifi
 */
void
update_lclgrp(vifi_t vifi, u_int32 mcastgrp)
{
    struct rtentry *r;
    struct gtable *g;
    
    IF_DEBUG(DEBUG_MEMBER)
    log(LOG_DEBUG, 0, "group %s joined on vif %d",
        inet_fmt(mcastgrp, s1), vifi);
    
    for (g = kernel_table; g; g = g->gt_gnext) {
        if (ntohl(mcastgrp) < ntohl(g->gt_mcastgrp))
            break;

        r = g->gt_route;
        if (g->gt_mcastgrp == mcastgrp &&
            VIFM_ISSET(vifi, r->rt_children)) {

            VIFM_SET(vifi, g->gt_grpmems);
            APPLY_SCOPE(g);
            if (VIFM_ISEMPTY(g->gt_grpmems))
                continue;

            prun_add_ttls(g);
            IF_DEBUG(DEBUG_CACHE)
            log(LOG_DEBUG, 0, "update lclgrp (%s %s) gm:%x",
                RT_FMT(r, s1),
                inet_fmt(g->gt_mcastgrp, s2), g->gt_grpmems);

            update_kernel(g);
#ifdef RSRR
            /* Send route change notification to reservation protocol. */
            rsrr_cache_send(g,1);
#endif /* RSRR */
        }
    }
}

/*
 * reset forwarding flag for all mcastgrps on this vifi
 */
void
delete_lclgrp(vifi_t vifi, u_int32 mcastgrp)
{
    struct gtable *g;
    
    IF_DEBUG(DEBUG_MEMBER)
    log(LOG_DEBUG, 0, "group %s left on vif %d",
        inet_fmt(mcastgrp, s1), vifi);
    
    for (g = kernel_table; g; g = g->gt_gnext) {
        if (ntohl(mcastgrp) < ntohl(g->gt_mcastgrp))
            break;

        if (g->gt_mcastgrp == mcastgrp && VIFM_ISSET(vifi, g->gt_grpmems)) {
            if (g->gt_route == NULL ||
                SUBS_ARE_PRUNED(g->gt_route->rt_subordinates,
                        uvifs[vifi].uv_nbrmap, g->gt_prunes)) {
                VIFM_CLR(vifi, g->gt_grpmems);
                IF_DEBUG(DEBUG_CACHE)
                log(LOG_DEBUG, 0, "delete lclgrp (%s %s) gm:%x",
                    RT_FMT(g->gt_route, s1),
                    inet_fmt(g->gt_mcastgrp, s2), g->gt_grpmems);

                prun_add_ttls(g);
                update_kernel(g);
#ifdef RSRR
                /* Send route change notification to reservation protocol. */
                rsrr_cache_send(g,1);
#endif /* RSRR */

                /*
                 * If there are no more members of this particular group,
                 *  send prune upstream
                 */
                if (VIFM_ISEMPTY(g->gt_grpmems) && g->gt_route->rt_gateway)
                    send_prune(g);
            }
        }
    }
}

/*
 * Takes the prune message received and then strips it to
 * determine the (src, grp) pair to be pruned.
 *
 * Adds the router to the (src, grp) entry then.
 *
 * Determines if further packets have to be sent down that vif
 *
 * Determines if a corresponding prune message has to be generated
 */
void
accept_prune(u_int32 src, u_int32 dst, char *p, int datalen)
{
    u_int32 prun_src;
    u_int32 prun_grp;
    u_int32 prun_tmr;
    vifi_t vifi;
    int i;
    struct rtentry *r;
    struct gtable *g;
    struct ptable *pt;
    
    if ((vifi = find_vif(src, dst)) == NO_VIF) {
        log(LOG_INFO, 0,
            "ignoring prune report from non-neighbor %s",
            inet_fmt(src, s1));
        return;
    }
    
    /* Check if enough data is present */
    if (datalen < 12)
        {
            log(LOG_WARNING, 0,
                "non-decipherable prune from %s",
                inet_fmt(src, s1));
            return;
        }
    
    for (i = 0; i< 4; i++)
        ((char *)&prun_src)[i] = *p++;
    for (i = 0; i< 4; i++)
        ((char *)&prun_grp)[i] = *p++;
    for (i = 0; i< 4; i++)
        ((char *)&prun_tmr)[i] = *p++;
    prun_tmr = ntohl(prun_tmr);
    
    if (prun_tmr <= MIN_PRUNE_LIFE) {
        IF_DEBUG(DEBUG_PRUNE)
        log(LOG_DEBUG, 0, "ignoring prune from %s on vif %d for (%s %s)/%d because its lifetime is too short",
        inet_fmt(src, s1), vifi,
        inet_fmt(prun_src, s2), inet_fmt(prun_grp, s3), prun_tmr);
        return;
    }

    IF_DEBUG(DEBUG_PRUNE)
    log(LOG_DEBUG, 0, "%s on vif %d prunes (%s %s)/%d",
        inet_fmt(src, s1), vifi,
        inet_fmt(prun_src, s2), inet_fmt(prun_grp, s3), prun_tmr);

    /*
     * Find the subnet for the prune
     */
    if (find_src_grp(prun_src, 0, prun_grp)) {
        g = gtp ? gtp->gt_gnext : kernel_table;
        r = g->gt_route;

        IF_DEBUG(DEBUG_PRUNE)
        log(LOG_DEBUG, 0, "found grp state, (%s %s), metric is %d, children are %x, subords are %08x%08x",
                RT_FMT(r, s1), inet_fmt(g->gt_mcastgrp, s2), r->rt_metric,
                r->rt_children, r->rt_subordinates.hi, r->rt_subordinates.lo);
        if (!VIFM_ISSET(vifi, r->rt_children)) {
            IF_DEBUG(DEBUG_PRUNE)
            log(LOG_WARNING, 0, "prune received from non-child %s for (%s %s) (dominant on vif %d is %s)",
                inet_fmt(src, s1), inet_fmt(prun_src, s2),
                inet_fmt(prun_grp, s3), vifi,
                inet_fmt(r->rt_dominants[vifi], s4));
#ifdef RINGBUFFER
            printringbuf();
#endif
            return;
        }
        if (VIFM_ISSET(vifi, g->gt_scope)) {
            log(LOG_WARNING, 0, "prune received from %s on scoped grp (%s %s)",
                inet_fmt(src, s1), inet_fmt(prun_src, s2),
                inet_fmt(prun_grp, s3));
            return;
        }
        if ((pt = find_prune_entry(src, g->gt_pruntbl)) != NULL) {
            IF_DEBUG(DEBUG_PRUNE)
            log(LOG_DEBUG, 0, "%s %d from %s for (%s %s)/%d %s %d %s %x",
                "duplicate prune received on vif",
                vifi, inet_fmt(src, s1), inet_fmt(prun_src, s2),
                inet_fmt(prun_grp, s3), prun_tmr,
                "old timer:", pt->pt_timer, "cur gm:", g->gt_grpmems);
            pt->pt_timer = prun_tmr;
        } else {
            struct listaddr *n = neighbor_info(vifi, src);

            if (!n) {
                log(LOG_WARNING, 0, "Prune from non-neighbor %s on vif %d!?",
                        inet_fmt(src, s1), vifi);
                return;
            }

            /* allocate space for the prune structure */
            pt = (struct ptable *)(malloc(sizeof(struct ptable)));
            if (pt == NULL)
              log(LOG_ERR, 0, "pt: ran out of memory");
                
            pt->pt_vifi = vifi;
            pt->pt_router = src;
            pt->pt_timer = prun_tmr;

            pt->pt_next = g->gt_pruntbl;
            g->gt_pruntbl = pt;

            if (n) {
                pt->pt_index = n->al_index;
                NBRM_SET(n->al_index, g->gt_prunes);
            }
        }

        /*
         * check if any more packets need to be sent on the 
         * vif which sent this message
         */
        if (SUBS_ARE_PRUNED(r->rt_subordinates,
                            uvifs[vifi].uv_nbrmap, g->gt_prunes) &&
                !grplst_mem(vifi, prun_grp)) {
            nbrbitmap_t tmp;

            VIFM_CLR(vifi, g->gt_grpmems);
            IF_DEBUG(DEBUG_PRUNE)
            log(LOG_DEBUG, 0, "vifnbrs=0x%08x%08x, subord=0x%08x%08x prunes=0x%08x%08x",
                uvifs[vifi].uv_nbrmap.hi,uvifs[vifi].uv_nbrmap.lo,
                r->rt_subordinates.hi, r->rt_subordinates.lo,
                g->gt_prunes.hi, g->gt_prunes.lo);
            /* XXX debugging */
            NBRM_COPY(r->rt_subordinates, tmp);
            NBRM_MASK(tmp, uvifs[vifi].uv_nbrmap);
            if (!NBRM_ISSETALLMASK(g->gt_prunes, tmp))
                log(LOG_WARNING, 0, "subordinate error");
            /* XXX end debugging */
            IF_DEBUG(DEBUG_PRUNE|DEBUG_CACHE)
            log(LOG_DEBUG, 0, "prune (%s %s), stop sending on vif %d, gm:%x",
                RT_FMT(r, s1),
                inet_fmt(g->gt_mcastgrp, s2), vifi, g->gt_grpmems);

            prun_add_ttls(g);
            update_kernel(g);
#ifdef RSRR
            /* Send route change notification to reservation protocol. */
            rsrr_cache_send(g,1);
#endif /* RSRR */
        }

        /*
         * check if all the child routers have expressed no interest
         * in this group and if this group does not exist in the 
         * interface
         * Send a prune message then upstream
         */
        if (VIFM_ISEMPTY(g->gt_grpmems) && r->rt_gateway) {
            send_prune(g);
        }
    } else {
        /*
         * There is no kernel entry for this group.  Therefore, we can
         * simply ignore the prune, as we are not forwarding this traffic
         * downstream.
         */
        IF_DEBUG(DEBUG_PRUNE|DEBUG_CACHE)
        log(LOG_DEBUG, 0, "%s (%s %s)/%d from %s",
            "prune message received with no kernel entry for",
            inet_fmt(prun_src, s1), inet_fmt(prun_grp, s2),
            prun_tmr, inet_fmt(src, s3));
        return;
    }
}

/*
 * Checks if this mcastgrp is present in the kernel table
 * If so and if a prune was sent, it sends a graft upwards
 */
void
chkgrp_graft(vifi_t vifi, u_int32 mcastgrp)
{
    struct rtentry *r;
    struct gtable *g;

    for (g = kernel_table; g; g = g->gt_gnext) {
        if (ntohl(mcastgrp) < ntohl(g->gt_mcastgrp))
            break;

        r = g->gt_route;
        if (g->gt_mcastgrp == mcastgrp && VIFM_ISSET(vifi, r->rt_children))
            if (g->gt_prsent_timer) {
                VIFM_SET(vifi, g->gt_grpmems);

                /*
                 * If the vif that was joined was a scoped vif,
                 * ignore it ; don't graft back
                 */
                APPLY_SCOPE(g);
                if (VIFM_ISEMPTY(g->gt_grpmems))
                    continue;

                /* send graft upwards */
                send_graft(g);
            
                /* update cache timer*/
                g->gt_timer = CACHE_LIFETIME(cache_lifetime);
            
                IF_DEBUG(DEBUG_PRUNE|DEBUG_CACHE)
                log(LOG_DEBUG, 0, "chkgrp graft (%s %s) gm:%x",
                    RT_FMT(r, s1),
                    inet_fmt(g->gt_mcastgrp, s2), g->gt_grpmems);

                prun_add_ttls(g);
                update_kernel(g);
#ifdef RSRR
                /* Send route change notification to reservation protocol. */
                rsrr_cache_send(g,1);
#endif /* RSRR */
            }
    }
}

/* determine the multicast group and src
 * 
 * if it does, then determine if a prune was sent 
 * upstream.
 * if prune sent upstream, send graft upstream and send
 * ack downstream.
 * 
 * if no prune sent upstream, change the forwarding bit
 * for this interface and send ack downstream.
 *
 * if no entry exists for this group send ack downstream.
 */
void
accept_graft(u_int32 src, u_int32 dst, char *p, int datalen)
{
    vifi_t      vifi;
    u_int32     graft_src;
    u_int32     graft_grp;
    int         i;
    struct rtentry *r;
    struct gtable *g;
    struct ptable *pt, **ptnp;
    
    if (datalen < 8) {
        log(LOG_WARNING, 0,
            "received non-decipherable graft from %s",
            inet_fmt(src, s1));
        return;
    }
    
    for (i = 0; i< 4; i++)
        ((char *)&graft_src)[i] = *p++;
    for (i = 0; i< 4; i++)
        ((char *)&graft_grp)[i] = *p++;

    vifi = find_vif(src, dst);
    send_graft_ack(dst, src, graft_src, graft_grp, vifi);

    if (vifi == NO_VIF) {
        log(LOG_INFO, 0,
            "ignoring graft for (%s %s) from non-neighbor %s",
            inet_fmt(graft_src, s2), inet_fmt(graft_grp, s3),
            inet_fmt(src, s1));
        return;
    }

    IF_DEBUG(DEBUG_PRUNE)
    log(LOG_DEBUG, 0, "%s on vif %d grafts (%s %s)",
        inet_fmt(src, s1), vifi,
        inet_fmt(graft_src, s2), inet_fmt(graft_grp, s3));
    
    /*
     * Find the subnet for the graft
     */
    if (find_src_grp(graft_src, 0, graft_grp)) {
        g = gtp ? gtp->gt_gnext : kernel_table;
        r = g->gt_route;

        if (VIFM_ISSET(vifi, g->gt_scope)) {
            log(LOG_WARNING, 0, "graft received from %s on scoped grp (%s %s)",
                inet_fmt(src, s1), inet_fmt(graft_src, s2),
                inet_fmt(graft_grp, s3));
            return;
        }

        ptnp = &g->gt_pruntbl;
        while ((pt = *ptnp) != NULL) {
            if ((pt->pt_vifi == vifi) && (pt->pt_router == src)) {
                NBRM_CLR(pt->pt_index, g->gt_prunes);
                *ptnp = pt->pt_next;
                free(pt);

                VIFM_SET(vifi, g->gt_grpmems);
                IF_DEBUG(DEBUG_PRUNE|DEBUG_CACHE)
                log(LOG_DEBUG, 0, "accept graft (%s %s) gm:%x",
                    RT_FMT(r, s1),
                    inet_fmt(g->gt_mcastgrp, s2), g->gt_grpmems);

                prun_add_ttls(g);
                update_kernel(g);
#ifdef RSRR
                /* Send route change notification to reservation protocol. */
                rsrr_cache_send(g,1);
#endif /* RSRR */
                break;                          
            } else {
                ptnp = &pt->pt_next;
            }
        }

        g->gt_timer = CACHE_LIFETIME(cache_lifetime);
            
        if (g->gt_prsent_timer)
            /* send graft upwards */
            send_graft(g);
    } else {
        /*
         * We have no state for the source and group in question.
         * This is fine, since we know that we have no prune state, and
         * grafts are requests to remove prune state.
         */
        IF_DEBUG(DEBUG_PRUNE)
        log(LOG_DEBUG, 0, "%s (%s %s) from %s",
            "graft received with no kernel entry for",
            inet_fmt(graft_src, s1), inet_fmt(graft_grp, s2),
            inet_fmt(src, s3));
        return;
    }
}

/*
 * find out which group is involved first of all 
 * then determine if a graft was sent.
 * if no graft sent, ignore the message
 * if graft was sent and the ack is from the right 
 * source, remove the graft timer so that we don't 
 * have send a graft again
 */
void
accept_g_ack(u_int32 src, u_int32 dst, char *p, int datalen)
{
    struct gtable *g;
    vifi_t      vifi;
    u_int32     grft_src;
    u_int32     grft_grp;
    int         i;
    
    if ((vifi = find_vif(src, dst)) == NO_VIF) {
        log(LOG_INFO, 0,
            "ignoring graft ack from non-neighbor %s",
            inet_fmt(src, s1));
        return;
    }
    
    if (datalen < 0  || datalen > 8) {
        log(LOG_WARNING, 0,
            "received non-decipherable graft ack from %s",
            inet_fmt(src, s1));
        return;
    }
    
    for (i = 0; i< 4; i++)
        ((char *)&grft_src)[i] = *p++;
    for (i = 0; i< 4; i++)
        ((char *)&grft_grp)[i] = *p++;
    
    IF_DEBUG(DEBUG_PRUNE)
    log(LOG_DEBUG, 0, "%s on vif %d acks graft (%s, %s)",
        inet_fmt(src, s1), vifi,
        inet_fmt(grft_src, s2), inet_fmt(grft_grp, s3));
    
    /*
     * Find the subnet for the graft ack
     */
    if (find_src_grp(grft_src, 0, grft_grp)) {
        g = gtp ? gtp->gt_gnext : kernel_table;
        g->gt_grftsnt = 0;
    } else {
        log(LOG_WARNING, 0, "%s (%s, %s) from %s",
            "rcvd graft ack with no kernel entry for",
            inet_fmt(grft_src, s1), inet_fmt(grft_grp, s2),
            inet_fmt(src, s3));
#ifdef RINGBUFFER
        printringbuf();
#endif
        return;
    }
}


/*
 * free all prune entries and kernel routes
 * normally, this should inform the kernel that all of its routes
 * are going away, but this is only called by restart(), which is
 * about to call MRT_DONE which does that anyway.
 */
void
free_all_prunes(void)
{
    struct rtentry *r;
    struct gtable *g, *prev_g;
    struct stable *s, *prev_s;
    struct ptable *p, *prev_p;

    for (r = routing_table; r; r = r->rt_next) {
        g = r->rt_groups;
        while (g) {
            s = g->gt_srctbl;
            while (s) {
                prev_s = s;
                s = s->st_next;
                free(prev_s);
            }

            p = g->gt_pruntbl;
            while (p) {
                prev_p = p;
                p = p->pt_next;
                free(prev_p);
            }

            prev_g = g;
            g = g->gt_next;
            if (prev_g->gt_rexmit_timer)
                timer_clearTimer(prev_g->gt_rexmit_timer);
            free(prev_g);
        }
        r->rt_groups = NULL;
    }
    kernel_table = NULL;

    g = kernel_no_route;
    while (g) {
        if (g->gt_srctbl)
            free(g->gt_srctbl);

        prev_g = g;
        g = g->gt_next;
        if (prev_g->gt_rexmit_timer)
            timer_clearTimer(prev_g->gt_rexmit_timer);
        free(prev_g);
    }
    kernel_no_route = NULL;
}

/*
 * When a new route is created, search
 * a) The less-specific part of the routing table
 * b) The route-less kernel table
 * for sources that the new route might want to handle.
 *
 * "Inheriting" these sources might be cleanest, but simply deleting
 * them is easier, and letting the kernel re-request them.
 */
void
steal_sources(struct rtentry *rt)
{
    struct rtentry *rp;
    struct gtable *gt, **gtnp;
    struct stable *st, **stnp;

    for (rp = rt->rt_next; rp; rp = rp->rt_next) {
        if (rp->rt_groups == NULL)
            continue;
        if ((rt->rt_origin & rp->rt_originmask) == rp->rt_origin) {
            IF_DEBUG(DEBUG_ROUTE)
            log(LOG_DEBUG, 0, "Route for %s stealing sources from %s",
                RT_FMT(rt, s1), RT_FMT(rp, s2));
            for (gt = rp->rt_groups; gt; gt = gt->gt_next) {
                stnp = &gt->gt_srctbl;
                while ((st = *stnp) != NULL) {
                    if ((st->st_origin & rt->rt_originmask) == rt->rt_origin) {
                        IF_DEBUG(DEBUG_ROUTE)
                        log(LOG_DEBUG, 0, "%s stealing (%s %s) from %s",
                            RT_FMT(rt, s1),
                            inet_fmt(st->st_origin, s3),
                            inet_fmt(gt->gt_mcastgrp, s4),
                            RT_FMT(rp, s2));
                        if (st->st_ctime != 0) {
                            if (k_del_rg(st->st_origin, gt) < 0) {
                                log(LOG_WARNING, errno, "%s (%s, %s)",
                                    "steal_sources trying to delete",
                                    inet_fmt(st->st_origin, s1),
                                    inet_fmt(gt->gt_mcastgrp, s2));
                            }
                            kroutes--;
                        }
                        *stnp = st->st_next;
                        free(st);
                    } else {
                        stnp = &st->st_next;
                    }
                }
            }
        }
    }

    gtnp = &kernel_no_route;
    while ((gt = *gtnp) != NULL) {
        if (gt->gt_srctbl && ((gt->gt_srctbl->st_origin & rt->rt_originmask)
                                    == rt->rt_origin)) {
            IF_DEBUG(DEBUG_ROUTE)
            log(LOG_DEBUG, 0, "%s stealing (%s %s) from %s",
                RT_FMT(rt, s1),
                inet_fmt(gt->gt_srctbl->st_origin, s3),
                inet_fmt(gt->gt_mcastgrp, s4),
                "no_route table");
            if (gt->gt_srctbl->st_ctime != 0) {
                if (k_del_rg(gt->gt_srctbl->st_origin, gt) < 0) {
                    log(LOG_WARNING, errno, "%s (%s %s)",
                        "steal_sources trying to delete",
                        inet_fmt(gt->gt_srctbl->st_origin, s1),
                        inet_fmt(gt->gt_mcastgrp, s2));
                }
                kroutes--;
            }
            free(gt->gt_srctbl);
            *gtnp = gt->gt_next;
            if (gt->gt_next)
                gt->gt_next->gt_prev = gt->gt_prev;
            if (gt->gt_rexmit_timer)
                timer_clearTimer(gt->gt_rexmit_timer);
            free(gt);
        } else {
            gtnp = &gt->gt_next;
        }
    }
}

/*
 * Advance the timers on all the cache entries.
 * If there are any entries whose timers have expired,
 * remove these entries from the kernel cache.
 */
void
age_table_entry(void)
{
    struct rtentry *r;
    struct gtable *gt, **gtnptr;
    struct stable *st, **stnp;
    struct ptable *pt, **ptnp;
    struct sioc_sg_req sg_req;
    
    IF_DEBUG(DEBUG_PRUNE|DEBUG_CACHE)
    log(LOG_DEBUG, 0, "aging forwarding cache entries");
    
    gtnptr = &kernel_table;
    while ((gt = *gtnptr) != NULL) {
        vifi_t i; /* XXX Debugging */
        int fixit = 0; /* XXX Debugging */

        r = gt->gt_route;

        /* XXX Debugging... */
        for (i = 0; i < numvifs; i++) {
            /*
             * If we're not sending on this vif,
             * And this group isn't scoped on this vif,
             * And I'm the parent for this route on this vif,
             * And there are subordinates on this vif,
             * And all of the subordinates haven't pruned,
             *          YELL LOUDLY
             *          and remember to fix it up later
             */
            if (!VIFM_ISSET(i, gt->gt_grpmems) &&
                !VIFM_ISSET(i, gt->gt_scope) &&
                VIFM_ISSET(i, r->rt_children) &&
                NBRM_ISSETMASK(uvifs[i].uv_nbrmap, r->rt_subordinates) &&
                !SUBS_ARE_PRUNED(r->rt_subordinates, uvifs[i].uv_nbrmap, gt->gt_prunes)) {
                log(LOG_WARNING, 0, "(%s %s) is blackholing on vif %d",
                    RT_FMT(r, s1), inet_fmt(gt->gt_mcastgrp, s2), i);
                fixit = 1;
            }
        }
        if (fixit) {
            log(LOG_WARNING, 0, "fixing membership for (%s %s) gm:%x",
                RT_FMT(r, s1), inet_fmt(gt->gt_mcastgrp, s2), gt->gt_grpmems);
            determine_forwvifs(gt);
            send_prune_or_graft(gt);
            log(LOG_WARNING, 0, "fixed  membership for (%s %s) gm:%x",
                RT_FMT(r, s1), inet_fmt(gt->gt_mcastgrp, s2), gt->gt_grpmems);
#ifdef RINGBUFFER
            printringbuf();
#endif
        }
        /*DEBUG2*/
        /* If there are group members,
         * and there are recent sources,
         * and we have a route,
         * and it's not directly connected,
         * and we haven't sent a prune,
         *      if there are any cache entries in the kernel
         *       [if there aren't we're probably waiting to rexmit],
         *              YELL LOUDLY
         *              and send a prune
         */
        if (VIFM_ISEMPTY(gt->gt_grpmems) && gt->gt_srctbl && r && r->rt_gateway && gt->gt_prsent_timer == 0) {
            for (st = gt->gt_srctbl; st; st = st->st_next)
                if (st->st_ctime != 0)
                    break;
            if (st != NULL) {
                log(LOG_WARNING, 0, "grpmems for (%s %s) is empty but no prune state!", RT_FMT(r, s1), inet_fmt(gt->gt_mcastgrp, s2));
                send_prune_or_graft(gt);
#ifdef RINGBUFFER
                printringbuf();
#endif
            }
        }
        /* XXX ...Debugging */

        /* advance the timer for the kernel entry */
        gt->gt_timer -= TIMER_INTERVAL;

        /* decrement prune timer if need be */
        if (gt->gt_prsent_timer > 0) {
            gt->gt_prsent_timer -= TIMER_INTERVAL;
            if (gt->gt_prsent_timer <= 0) {
                IF_DEBUG(DEBUG_PRUNE)
                log(LOG_DEBUG, 0, "upstream prune tmo (%s %s)",
                    RT_FMT(r, s1),
                    inet_fmt(gt->gt_mcastgrp, s2));
                gt->gt_prsent_timer = -1;
                /* Reset the prune retransmission timer to its initial value */
                gt->gt_prune_rexmit = PRUNE_REXMIT_VAL;
            }
        }

        /* retransmit graft with exponential backoff */
        if (gt->gt_grftsnt) {
            int y;

            y = ++gt->gt_grftsnt;
            while (y && !(y & 1))
                y >>= 1;
            if (y == 1)
                send_graft(gt);
        }

        /*
         * Age prunes
         *
         * If a prune expires, forward again on that vif.
         */
        ptnp = &gt->gt_pruntbl;
        while ((pt = *ptnp) != NULL) {
            if ((pt->pt_timer -= TIMER_INTERVAL) <= 0) {
                IF_DEBUG(DEBUG_PRUNE)
                log(LOG_DEBUG, 0, "expire prune (%s %s) from %s on vif %d", 
                    RT_FMT(r, s1),
                    inet_fmt(gt->gt_mcastgrp, s2),
                    inet_fmt(pt->pt_router, s3),
                    pt->pt_vifi);
                if (gt->gt_prsent_timer > 0) {
                    log(LOG_WARNING, 0, "prune (%s %s) from %s on vif %d expires with %d left on prsent timer",
                        RT_FMT(r, s1),
                        inet_fmt(gt->gt_mcastgrp, s2),
                        inet_fmt(pt->pt_router, s3),
                        pt->pt_vifi, gt->gt_prsent_timer);
                    /* Send a graft to heal the tree. */
                    send_graft(gt);
                }

                NBRM_CLR(pt->pt_index, gt->gt_prunes);
                expire_prune(pt->pt_vifi, gt);

                /* remove the router's prune entry and await new one */
                *ptnp = pt->pt_next;
                free(pt);
            } else {
                ptnp = &pt->pt_next;
            }
        }

        /*
         * If the cache entry has expired, delete source table entries for
         * silent sources.  If there are no source entries left, and there
         * are no downstream prunes, then the entry is deleted.
         * Otherwise, the cache entry's timer is refreshed.
         */
        if (gt->gt_timer <= 0) {
            IF_DEBUG(DEBUG_CACHE)
            log(LOG_DEBUG, 0, "(%s %s) timed out, checking for traffic",
                RT_FMT(gt->gt_route, s1),
                inet_fmt(gt->gt_mcastgrp, s2));
            /* Check for traffic before deleting source entries */
            sg_req.grp.s_addr = gt->gt_mcastgrp;
            stnp = &gt->gt_srctbl;
            while ((st = *stnp) != NULL) {
                /*
                 * Source entries with no ctime are not actually in the
                 * kernel; they have been removed by rexmit_prune() so
                 * are safe to remove from the list at this point.
                 */
                if (st->st_ctime) {
                    sg_req.src.s_addr = st->st_origin;
                    if (ioctl(udp_socket, SIOCGETSGCNT, (char *)&sg_req) < 0) {
                        log(LOG_WARNING, errno, "%s (%s %s)",
                            "age_table_entry: SIOCGETSGCNT failing for",
                            inet_fmt(st->st_origin, s1),
                            inet_fmt(gt->gt_mcastgrp, s2));
                        /* Make sure it gets deleted below */
                        sg_req.pktcnt = st->st_pktcnt;
                    }
                } else {
                    sg_req.pktcnt = st->st_pktcnt;
                }
                if (sg_req.pktcnt == st->st_pktcnt) {
                    *stnp = st->st_next;
                    IF_DEBUG(DEBUG_CACHE)
                    log(LOG_DEBUG, 0, "age_table_entry deleting (%s %s)",
                        inet_fmt(st->st_origin, s1),
                        inet_fmt(gt->gt_mcastgrp, s2));
                    if (st->st_ctime != 0) {
                        if (k_del_rg(st->st_origin, gt) < 0) {
                            log(LOG_WARNING, errno,
                                "age_table_entry trying to delete (%s %s)",
                                inet_fmt(st->st_origin, s1),
                                inet_fmt(gt->gt_mcastgrp, s2));
                        }
                        kroutes--;
                    }
                    free(st);
                } else {
                    st->st_pktcnt = sg_req.pktcnt;
                    stnp = &st->st_next;
                }
            }

            /*
             * Retain the group entry if we have downstream prunes or if
             * there is at least one source in the list that still has
             * traffic, or if our upstream prune timer or graft
             * retransmission timer is running.
             */
            if (gt->gt_pruntbl != NULL || gt->gt_srctbl != NULL ||
                gt->gt_prsent_timer > 0 || gt->gt_grftsnt > 0) {
                IF_DEBUG(DEBUG_CACHE)
                log(LOG_DEBUG, 0, "refresh lifetim of cache entry %s%s%s%s(%s, %s)",
                        gt->gt_pruntbl ? "(dstrm prunes) " : "",
                        gt->gt_srctbl ? "(trfc flow) " : "",
                        gt->gt_prsent_timer > 0 ? "(upstrm prune) " : "",
                        gt->gt_grftsnt > 0 ? "(grft rexmit) " : "",
                        RT_FMT(r, s1),
                        inet_fmt(gt->gt_mcastgrp, s2));
                gt->gt_timer = CACHE_LIFETIME(cache_lifetime);
                if (gt->gt_prsent_timer == -1) {
                    /*
                     * The upstream prune timed out.  Remove any kernel
                     * state.
                     */
                    gt->gt_prsent_timer = 0;
                    if (gt->gt_pruntbl) {
                        log(LOG_WARNING, 0, "upstream prune for (%s %s) expires with downstream prunes active",
                                RT_FMT(r, s1), inet_fmt(gt->gt_mcastgrp, s2));
                    }
                    remove_sources(gt);
                }
                gtnptr = &gt->gt_gnext;
                continue;
            }

            IF_DEBUG(DEBUG_CACHE)
            log(LOG_DEBUG, 0, "timeout cache entry (%s, %s)",
                RT_FMT(r, s1),
                inet_fmt(gt->gt_mcastgrp, s2));
            
            if (gt->gt_prev)
                gt->gt_prev->gt_next = gt->gt_next;
            else
                gt->gt_route->rt_groups = gt->gt_next;
            if (gt->gt_next)
                gt->gt_next->gt_prev = gt->gt_prev;

            if (gt->gt_gprev) {
                gt->gt_gprev->gt_gnext = gt->gt_gnext;
                gtnptr = &gt->gt_gprev->gt_gnext;
            } else {
                kernel_table = gt->gt_gnext;
                gtnptr = &kernel_table;
            }
            if (gt->gt_gnext)
                gt->gt_gnext->gt_gprev = gt->gt_gprev;

#ifdef RSRR
            /* Send route change notification to reservation protocol. */
            rsrr_cache_send(gt,0);
            rsrr_cache_clean(gt);
#endif /* RSRR */
            if (gt->gt_rexmit_timer)
                timer_clearTimer(gt->gt_rexmit_timer);

            free((char *)gt);
        } else {
            if (gt->gt_prsent_timer == -1) {
                /*
                 * The upstream prune timed out.  Remove any kernel
                 * state.
                 */
                gt->gt_prsent_timer = 0;
                if (gt->gt_pruntbl) {
                    log(LOG_WARNING, 0, "upstream prune for (%s %s) expires with downstream prunes active",
                            RT_FMT(r, s1), inet_fmt(gt->gt_mcastgrp, s2));
                }
                remove_sources(gt);
            }
            gtnptr = &gt->gt_gnext;
        }
    }

    /*
     * When traversing the no_route table, the decision is much easier.
     * Just delete it if it has timed out.
     */
    gtnptr = &kernel_no_route;
    while ((gt = *gtnptr) != NULL) {
        /* advance the timer for the kernel entry */
        gt->gt_timer -= TIMER_INTERVAL;

        if (gt->gt_timer < 0) {
            if (gt->gt_srctbl) {
                if (gt->gt_srctbl->st_ctime != 0) {
                    if (k_del_rg(gt->gt_srctbl->st_origin, gt) < 0) {
                        log(LOG_WARNING, errno, "%s (%s %s)",
                            "age_table_entry trying to delete no-route",
                            inet_fmt(gt->gt_srctbl->st_origin, s1),
                            inet_fmt(gt->gt_mcastgrp, s2));
                    }
                    kroutes--;
                }
                free(gt->gt_srctbl);
            }
            *gtnptr = gt->gt_next;
            if (gt->gt_next)
                gt->gt_next->gt_prev = gt->gt_prev;

            if (gt->gt_rexmit_timer)
                timer_clearTimer(gt->gt_rexmit_timer);

            free((char *)gt);
        } else {
            gtnptr = &gt->gt_next;
        }
    }
}

/*
 * Modify the kernel to forward packets when one or multiple prunes that
 * were received on the vif given by vifi, for the group given by gt,
 * have expired.
 */
static void
expire_prune(vifi_t vifi, struct gtable *gt)
{
    /*
     * No need to send a graft, any prunes that we sent
     * will expire before any prunes that we have received.
     * However, in the case that we did make a mistake,
     * send a graft to compensate.
     */
    if (gt->gt_prsent_timer >= MIN_PRUNE_LIFE) {
        IF_DEBUG(DEBUG_PRUNE)
        log(LOG_DEBUG, 0, "prune expired with %d left on %s",
                gt->gt_prsent_timer, "prsent_timer");
        gt->gt_prsent_timer = 0;
        send_graft(gt);
    }

    /* modify the kernel entry to forward packets */
    if (!VIFM_ISSET(vifi, gt->gt_grpmems)) {
        struct rtentry *rt = gt->gt_route;
        VIFM_SET(vifi, gt->gt_grpmems);
        IF_DEBUG(DEBUG_CACHE)
        log(LOG_DEBUG, 0, "forw again (%s %s) gm:%x vif:%d",
        RT_FMT(rt, s1),
        inet_fmt(gt->gt_mcastgrp, s2), gt->gt_grpmems, vifi);

        prun_add_ttls(gt);
        update_kernel(gt);
#ifdef RSRR
        /* Send route change notification to reservation protocol. */
        rsrr_cache_send(gt,1);
#endif /* RSRR */
    }
}

/*
 * Print the contents of the cache table on file 'fp2'.
 */
void
dump_cache(FILE *fp2)
{
    struct rtentry *r;
    struct gtable *gt;
    struct stable *st;
    struct ptable *pt;
    vifi_t i;
    char c;
    time_t thyme;

    thyme = time(0);
    fprintf(fp2,
            "Multicast Routing Cache Table (%d entries)\n%s", kroutes,
    " Origin             Mcast-group         CTmr     Age      Ptmr Rx IVif Forwvifs\n");
    fprintf(fp2,
    "<(prunesrc:vif[idx]/tmr) prunebitmap\n%s",
    ">Source             Lifetime SavPkt         Pkts    Bytes RPFf\n");
    
    for (gt = kernel_no_route; gt; gt = gt->gt_next) {
        if (gt->gt_srctbl) {
            fprintf(fp2, " %-18s %-15s %-8s %-8s        - -1 (no route)\n",
                inet_fmts(gt->gt_srctbl->st_origin, 0xffffffff, s1),
                inet_fmt(gt->gt_mcastgrp, s2), scaletime(gt->gt_timer),
                scaletime(thyme - gt->gt_ctime));
            fprintf(fp2, ">%s\n", inet_fmt(gt->gt_srctbl->st_origin, s1));
        }
    }

    for (gt = kernel_table; gt; gt = gt->gt_gnext) {
        r = gt->gt_route;
        fprintf(fp2, " %-18s %-15s",
            RT_FMT(r, s1),
            inet_fmt(gt->gt_mcastgrp, s2));

        fprintf(fp2, " %-8s", scaletime(gt->gt_timer));

        fprintf(fp2, " %-8s %-8s ", scaletime(thyme - gt->gt_ctime),
                        gt->gt_prsent_timer ? scaletime(gt->gt_prsent_timer) :
                                              "       -");

        if (gt->gt_prune_rexmit) {
            int i = gt->gt_prune_rexmit;
            int n = 0;

            while (i > PRUNE_REXMIT_VAL) {
                n++;
                i /= 2;
            }
            if (n == 0 && gt->gt_prsent_timer == 0)
                fprintf(fp2, " -");
            else
                fprintf(fp2, "%2d", n);
        } else {
            fprintf(fp2, " -");
        }

        fprintf(fp2, " %2u%c%c", r->rt_parent,
            gt->gt_prsent_timer ? 'P' :
                                  gt->gt_grftsnt ? 'G' : ' ',
            VIFM_ISSET(r->rt_parent, gt->gt_scope) ? 'B' : ' ');

        for (i = 0; i < numvifs; ++i) {
            if (VIFM_ISSET(i, gt->gt_grpmems))
                fprintf(fp2, " %u ", i);
            else if (VIFM_ISSET(i, r->rt_children) &&
                     NBRM_ISSETMASK(uvifs[i].uv_nbrmap, r->rt_subordinates))
                fprintf(fp2, " %u%c", i,
                        VIFM_ISSET(i, gt->gt_scope) ? 'b' : 
                        SUBS_ARE_PRUNED(r->rt_subordinates,
                            uvifs[i].uv_nbrmap, gt->gt_prunes) ? 'p' : '!');
        }
        fprintf(fp2, "\n");
        if (gt->gt_pruntbl) {
            fprintf(fp2, "<");
            c = '(';
            for (pt = gt->gt_pruntbl; pt; pt = pt->pt_next) {
                fprintf(fp2, "%c%s:%d[%d]/%d", c, inet_fmt(pt->pt_router, s1),
                    pt->pt_vifi, pt->pt_index, pt->pt_timer);
                c = ',';
            }
            fprintf(fp2, ")");
            fprintf(fp2, " 0x%08lx%08lx\n",/*XXX*/
                    gt->gt_prunes.hi, gt->gt_prunes.lo);
        }
        for (st = gt->gt_srctbl; st; st = st->st_next) {
            fprintf(fp2, ">%-18s %-8s %6ld", inet_fmt(st->st_origin, s1),
                st->st_ctime ? scaletime(thyme - st->st_ctime) : "-",
                st->st_savpkt);
            if (st->st_ctime) {
                struct sioc_sg_req sg_req;

                sg_req.src.s_addr = st->st_origin;
                sg_req.grp.s_addr = gt->gt_mcastgrp;
                if (ioctl(udp_socket, SIOCGETSGCNT, (char *)&sg_req) < 0) {
                    log(LOG_WARNING, errno, "SIOCGETSGCNT on (%s %s)",
                        inet_fmt(st->st_origin, s1),
                        inet_fmt(gt->gt_mcastgrp, s2));
                } else {
                    fprintf(fp2, "     %8ld %8ld %4ld", sg_req.pktcnt,
                        sg_req.bytecnt, sg_req.wrong_if);
                }
            }
            fprintf(fp2, "\n");
        }
    }
}

/*
 * Traceroute function which returns traceroute replies to the requesting
 * router. Also forwards the request to downstream routers.
 */
void
accept_mtrace(u_int32 src, u_int32 dst, u_int32 group, char *data,
              u_int no, /* promoted u_char */
              int datalen)
{
    u_char type;
    struct rtentry *rt;
    struct gtable *gt;
    struct tr_query *qry;
    struct tr_resp  *resp;
    int vifi;
    char *p;
    int rcount;
    int errcode = TR_NO_ERR;
    int resptype;
    struct timeval tp;
    struct sioc_vif_req v_req;
    struct sioc_sg_req sg_req;

    /* Remember qid across invocations */
    static u_int32 oqid = 0;

    /* timestamp the request/response */
    gettimeofday(&tp, 0);

    /*
     * Check if it is a query or a response
     */
    if (datalen == QLEN) {
        type = QUERY;
        IF_DEBUG(DEBUG_TRACE)
        log(LOG_DEBUG, 0, "Initial traceroute query rcvd from %s to %s",
            inet_fmt(src, s1), inet_fmt(dst, s2));
    }
    else if ((datalen - QLEN) % RLEN == 0) {
        type = RESP;
        IF_DEBUG(DEBUG_TRACE)
        log(LOG_DEBUG, 0, "In-transit traceroute query rcvd from %s to %s",
            inet_fmt(src, s1), inet_fmt(dst, s2));
        if (IN_MULTICAST(ntohl(dst))) {
            IF_DEBUG(DEBUG_TRACE)
            log(LOG_DEBUG, 0, "Dropping multicast response");
            return;
        }
    }
    else {
        log(LOG_WARNING, 0, "%s from %s to %s",
            "Non decipherable traceroute request received",
            inet_fmt(src, s1), inet_fmt(dst, s2));
        return;
    }

    qry = (struct tr_query *)data;

    /*
     * if it is a packet with all reports filled, drop it
     */
    if ((rcount = (datalen - QLEN)/RLEN) == no) {
        IF_DEBUG(DEBUG_TRACE)
        log(LOG_DEBUG, 0, "packet with all reports filled in");
        return;
    }

    IF_DEBUG(DEBUG_TRACE) {
    log(LOG_DEBUG, 0, "s: %s g: %s d: %s ", inet_fmt(qry->tr_src, s1),
            inet_fmt(group, s2), inet_fmt(qry->tr_dst, s3));
    log(LOG_DEBUG, 0, "rttl: %d rd: %s", qry->tr_rttl,
            inet_fmt(qry->tr_raddr, s1));
    log(LOG_DEBUG, 0, "rcount:%d, qid:%06x", rcount, qry->tr_qid);
    }

    /* determine the routing table entry for this traceroute */
    rt = determine_route(qry->tr_src);
    IF_DEBUG(DEBUG_TRACE)
    if (rt) {
        log(LOG_DEBUG, 0, "rt parent vif: %d rtr: %s metric: %d",
                rt->rt_parent, inet_fmt(rt->rt_gateway, s1), rt->rt_metric);
        log(LOG_DEBUG, 0, "rt origin %s",
                RT_FMT(rt, s1));
    } else
        log(LOG_DEBUG, 0, "...no route");

    /*
     * Query type packet - check if rte exists 
     * Check if the query destination is a vif connected to me.
     * and if so, whether I should start response back
     */
    if (type == QUERY) {
        if (oqid == qry->tr_qid) {
            /*
             * If the multicast router is a member of the group being
             * queried, and the query is multicasted, then the router can
             * recieve multiple copies of the same query.  If we have already
             * replied to this traceroute, just ignore it this time.
             *
             * This is not a total solution, but since if this fails you
             * only get N copies, N <= the number of interfaces on the router,
             * it is not fatal.
             */
            IF_DEBUG(DEBUG_TRACE)
            log(LOG_DEBUG, 0, "ignoring duplicate traceroute packet");
            return;
        }

        if (rt == NULL) {
            IF_DEBUG(DEBUG_TRACE)
            log(LOG_DEBUG, 0, "Mcast traceroute: no route entry %s",
                   inet_fmt(qry->tr_src, s1));
            if (IN_MULTICAST(ntohl(dst)))
                return;
        }
        vifi = find_vif(qry->tr_dst, 0);
        
        if (vifi == NO_VIF) {
            /* The traceroute destination is not on one of my subnet vifs. */
            IF_DEBUG(DEBUG_TRACE)
            log(LOG_DEBUG, 0, "Destination %s not an interface",
                   inet_fmt(qry->tr_dst, s1));
            if (IN_MULTICAST(ntohl(dst)))
                return;
            errcode = TR_WRONG_IF;
        } else if (rt != NULL && !VIFM_ISSET(vifi, rt->rt_children)) {
            IF_DEBUG(DEBUG_TRACE)
            log(LOG_DEBUG, 0, "Destination %s not on forwarding tree for src %s",
                   inet_fmt(qry->tr_dst, s1), inet_fmt(qry->tr_src, s2));
            if (IN_MULTICAST(ntohl(dst)))
                return;
            errcode = TR_WRONG_IF;
        }
    }
    else {
        /*
         * determine which interface the packet came in on
         * RESP packets travel hop-by-hop so this either traversed
         * a tunnel or came from a directly attached mrouter.
         */
        if ((vifi = find_vif(src, dst)) == NO_VIF) {
            IF_DEBUG(DEBUG_TRACE)
            log(LOG_DEBUG, 0, "Wrong interface for packet");
            errcode = TR_WRONG_IF;
        }
    }   
    
    /* Now that we've decided to send a response, save the qid */
    oqid = qry->tr_qid;

    IF_DEBUG(DEBUG_TRACE)
    log(LOG_DEBUG, 0, "Sending traceroute response");
    
    /* copy the packet to the sending buffer */
    p = send_buf + MIN_IP_HEADER_LEN + IGMP_MINLEN;
    
    bcopy(data, p, datalen);
    
    p += datalen;
    
    /*
     * If there is no room to insert our reply, coopt the previous hop
     * error indication to relay this fact.
     */
    if (p + sizeof(struct tr_resp) > send_buf + RECV_BUF_SIZE) {
        resp = (struct tr_resp *)p - 1;
        resp->tr_rflags = TR_NO_SPACE;
        rt = NULL;
        goto sendit;
    }

    /*
     * fill in initial response fields
     */
    resp = (struct tr_resp *)p;
    bzero(resp, sizeof(struct tr_resp));
    datalen += RLEN;

    resp->tr_qarr    = htonl(((tp.tv_sec + JAN_1970) << 16) + 
                                ((tp.tv_usec << 10) / 15625));

    resp->tr_rproto  = PROTO_DVMRP;
    resp->tr_outaddr = (vifi == NO_VIF) ? dst : uvifs[vifi].uv_lcl_addr;
    resp->tr_fttl    = (vifi == NO_VIF) ? 0 : uvifs[vifi].uv_threshold;
    resp->tr_rflags  = errcode;

    /*
     * obtain # of packets out on interface
     */
    v_req.vifi = vifi;
    if (vifi != NO_VIF && ioctl(udp_socket, SIOCGETVIFCNT, (char *)&v_req) >= 0)
        resp->tr_vifout  =  htonl(v_req.ocount);
    else
        resp->tr_vifout  =  0xffffffff;

    /*
     * fill in scoping & pruning information
     */
    if (rt)
        for (gt = rt->rt_groups; gt; gt = gt->gt_next) {
            if (gt->gt_mcastgrp >= group)
                break;
        }
    else
        gt = NULL;

    if (gt && gt->gt_mcastgrp == group) {
        struct stable *st;

        for (st = gt->gt_srctbl; st; st = st->st_next)
            if (qry->tr_src == st->st_origin)
                break;

        sg_req.src.s_addr = qry->tr_src;
        sg_req.grp.s_addr = group;
        if (st && st->st_ctime != 0 &&
                  ioctl(udp_socket, SIOCGETSGCNT, (char *)&sg_req) >= 0)
            resp->tr_pktcnt = htonl(sg_req.pktcnt + st->st_savpkt);
        else
            resp->tr_pktcnt = htonl(st ? st->st_savpkt : 0xffffffff);

        if (VIFM_ISSET(vifi, gt->gt_scope))
            resp->tr_rflags = TR_SCOPED;
        else if (gt->gt_prsent_timer)
            resp->tr_rflags = TR_PRUNED;
        else if (!VIFM_ISSET(vifi, gt->gt_grpmems))
            if (!NBRM_ISEMPTY(uvifs[vifi].uv_nbrmap) &&
                SUBS_ARE_PRUNED(rt->rt_subordinates,
                                uvifs[vifi].uv_nbrmap, gt->gt_prunes))
                resp->tr_rflags = TR_OPRUNED;
            else
                resp->tr_rflags = TR_NO_FWD;
    } else {
        if ((vifi != NO_VIF && scoped_addr(vifi, group)) ||
            (rt && scoped_addr(rt->rt_parent, group)))
            resp->tr_rflags = TR_SCOPED;
        else if (rt && !VIFM_ISSET(vifi, rt->rt_children))
            resp->tr_rflags = TR_NO_FWD;
    }

    /*
     *  if no rte exists, set NO_RTE error
     */
    if (rt == NULL) {
        src = dst;              /* the dst address of resp. pkt */
        resp->tr_inaddr   = 0;
        resp->tr_rflags   = TR_NO_RTE;
        resp->tr_rmtaddr  = 0;
    } else {
        /* get # of packets in on interface */
        v_req.vifi = rt->rt_parent;
        if (ioctl(udp_socket, SIOCGETVIFCNT, (char *)&v_req) >= 0)
            resp->tr_vifin = htonl(v_req.icount);
        else
            resp->tr_vifin = 0xffffffff;

        MASK_TO_VAL(rt->rt_originmask, resp->tr_smask);
        src = uvifs[rt->rt_parent].uv_lcl_addr;
        resp->tr_inaddr = src;
        resp->tr_rmtaddr = rt->rt_gateway;
        if (!VIFM_ISSET(vifi, rt->rt_children)) {
            IF_DEBUG(DEBUG_TRACE)
            log(LOG_DEBUG, 0, "Destination %s not on forwarding tree for src %s",
                   inet_fmt(qry->tr_dst, s1), inet_fmt(qry->tr_src, s2));
            resp->tr_rflags = TR_WRONG_IF;
        }
        if (rt->rt_metric >= UNREACHABLE) {
            resp->tr_rflags = TR_NO_RTE;
            /* Hack to send reply directly */
            rt = NULL;
        }
    }

sendit:
    /*
     * if metric is 1 or no. of reports is 1, send response to requestor
     * else send to upstream router.  If the upstream router can't handle
     * mtrace, set an error code and send to requestor anyway.
     */
    IF_DEBUG(DEBUG_TRACE)
    log(LOG_DEBUG, 0, "rcount:%d, no:%d", rcount, no);

    if ((rcount + 1 == no) || (rt == NULL) || (rt->rt_metric == 1)) {
        resptype = IGMP_MTRACE_RESP;
        dst = qry->tr_raddr;
    } else
        if (!can_mtrace(rt->rt_parent, rt->rt_gateway)) {
            dst = qry->tr_raddr;
            resp->tr_rflags = TR_OLD_ROUTER;
            resptype = IGMP_MTRACE_RESP;
        } else {
            dst = rt->rt_gateway;
            resptype = IGMP_MTRACE;
        }

    if (IN_MULTICAST(ntohl(dst))) {
        /*
         * Send the reply on a known multicast capable vif.
         * If we don't have one, we can't source any multicasts anyway.
         */
        if (phys_vif != -1) {
            IF_DEBUG(DEBUG_TRACE)
            log(LOG_DEBUG, 0, "Sending reply to %s from %s",
                inet_fmt(dst, s1), inet_fmt(uvifs[phys_vif].uv_lcl_addr, s2));
            k_set_ttl(qry->tr_rttl);
            send_igmp(uvifs[phys_vif].uv_lcl_addr, dst,
                      resptype, no, group,
                      datalen);
            k_set_ttl(1);
        } else
            log(LOG_INFO, 0, "No enabled phyints -- %s",
                        "dropping traceroute reply");
    } else {
        IF_DEBUG(DEBUG_TRACE)
        log(LOG_DEBUG, 0, "Sending %s to %s from %s",
            resptype == IGMP_MTRACE_RESP ?  "reply" : "request on",
            inet_fmt(dst, s1), inet_fmt(src, s2));

        send_igmp(src, dst,
                  resptype, no, group,
                  datalen);
    }
    return;
}