/*      $NetBSD: vif.c,v 1.19 2015/02/05 16:50:19 gdt Exp $     */

/*
* 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.
*/


#include "defs.h"
#include <fcntl.h>

/*
* Exported variables.
*/
struct uvif     uvifs[MAXVIFS]; /* array of virtual interfaces              */
vifi_t          numvifs;        /* number of vifs in use                    */
int             vifs_down;      /* 1=>some interfaces are down              */
int             phys_vif;       /* An enabled vif                           */
int             udp_socket;     /* Since the honkin' kernel doesn't support */
                               /* ioctls on raw IP sockets, we need a UDP  */
                               /* socket as well as our IGMP (raw) socket. */
                               /* How dumb.                                */
int             vifs_with_neighbors;    /* == 1 if I am a leaf              */

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

/*
* Forward declarations.
*/
static void start_vif(vifi_t vifi);
static void start_vif2(vifi_t vifi);
static void stop_vif(vifi_t vifi);
static void age_old_hosts(void);
static void send_probe_on_vif(struct uvif *v);
static int info_version(char *p, size_t);
static void DelVif(void *arg);
static int SetTimer(vifi_t vifi, struct listaddr *g);
static int DeleteTimer(int id);
static void SendQuery(void *arg);
static int SetQueryTimer(struct listaddr *g, vifi_t vifi, int to_expire,
                        int q_time);


/*
* Initialize the virtual interfaces, but do not install
* them in the kernel.  Start routing on all vifs that are
* not down or disabled.
*/
void
init_vifs(void)
{
   vifi_t vifi;
   struct uvif *v;
   int enabled_vifs, enabled_phyints;
   extern char *configfilename;

   numvifs = 0;
   vifs_with_neighbors = 0;
   vifs_down = FALSE;

   /*
    * Configure the vifs based on the interface configuration of the
    * the kernel and the contents of the configuration file.
    * (Open a UDP socket for ioctl use in the config procedures.)
    */
   if ((udp_socket = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
       logit(LOG_ERR, errno, "UDP socket");
   logit(LOG_INFO,0,"Getting vifs from kernel interfaces");
   config_vifs_from_kernel();
   logit(LOG_INFO,0,"Getting vifs from %s",configfilename);
   config_vifs_from_file();

   /*
    * Quit if there are fewer than two enabled vifs.
    */
   enabled_vifs    = 0;
   enabled_phyints = 0;
   phys_vif        = -1;
   for (vifi = 0, v = uvifs; vifi < numvifs; ++vifi, ++v) {
       if (!(v->uv_flags & VIFF_DISABLED)) {
           ++enabled_vifs;
           if (!(v->uv_flags & VIFF_TUNNEL)) {
               if (phys_vif == -1)
                   phys_vif = vifi;
               ++enabled_phyints;
           }
       }
   }
   if (enabled_vifs < 2)
       logit(LOG_ERR, 0, "can't forward: %s",
           enabled_vifs == 0 ? "no enabled vifs" : "only one enabled vif");

   if (enabled_phyints == 0)
       logit(LOG_WARNING, 0,
           "no enabled interfaces, forwarding via tunnels only");

   logit(LOG_INFO, 0, "Installing vifs in mrouted...");
   for (vifi = 0, v = uvifs; vifi < numvifs; ++vifi, ++v) {
       if (!(v->uv_flags & VIFF_DISABLED)) {
           if (!(v->uv_flags & VIFF_DOWN)) {
               if (v->uv_flags & VIFF_TUNNEL)
                   logit(LOG_INFO, 0, "vif #%d, tunnel %s -> %s", vifi,
                               inet_fmt(v->uv_lcl_addr),
                               inet_fmt(v->uv_rmt_addr));
               else
                   logit(LOG_INFO, 0, "vif #%d, phyint %s", vifi,
                               inet_fmt(v->uv_lcl_addr));
               start_vif2(vifi);
           } else logit(LOG_INFO, 0,
                    "%s is not yet up; vif #%u not in service",
                    v->uv_name, vifi);
       }
   }
}

/*
* Start routing on all virtual interfaces that are not down or
* administratively disabled.
*/
void
init_installvifs(void)
{
   vifi_t vifi;
   struct uvif *v;

   logit(LOG_INFO, 0, "Installing vifs in kernel...");
   for (vifi = 0, v = uvifs; vifi < numvifs; ++vifi, ++v) {
       if (!(v->uv_flags & VIFF_DISABLED)) {
           if (!(v->uv_flags & VIFF_DOWN)) {
               if (v->uv_flags & VIFF_TUNNEL)
                   logit(LOG_INFO, 0, "vif #%d, tunnel %s -> %s", vifi,
                               inet_fmt(v->uv_lcl_addr),
                               inet_fmt(v->uv_rmt_addr));
               else
                   logit(LOG_INFO, 0, "vif #%d, phyint %s", vifi,
                               inet_fmt(v->uv_lcl_addr));
               k_add_vif(vifi, &uvifs[vifi]);
           } else logit(LOG_INFO, 0,
                    "%s is not yet up; vif #%u not in service",
                    v->uv_name, vifi);
       }
   }
}

/*
* See if any interfaces have changed from up state to down, or vice versa,
* including any non-multicast-capable interfaces that are in use as local
* tunnel end-points.  Ignore interfaces that have been administratively
* disabled.
*/
void
check_vif_state(void)
{
   vifi_t vifi;
   struct uvif *v;
   struct ifreq ifr;

   vifs_down = FALSE;
   for (vifi = 0, v = uvifs; vifi < numvifs; ++vifi, ++v) {

       if (v->uv_flags & VIFF_DISABLED) continue;

       strncpy(ifr.ifr_name, v->uv_name, IFNAMSIZ);
       if (ioctl(udp_socket, SIOCGIFFLAGS, (char *)&ifr) < 0)
           logit(LOG_ERR, errno,
               "ioctl SIOCGIFFLAGS for %s", ifr.ifr_name);

       if (v->uv_flags & VIFF_DOWN) {
           if (ifr.ifr_flags & IFF_UP) {
               v->uv_flags &= ~VIFF_DOWN;
               start_vif(vifi);
               logit(LOG_INFO, 0,
                   "%s has come up; vif #%u now in service",
                   v->uv_name, vifi);
           }
           else vifs_down = TRUE;
       }
       else {
           if (!(ifr.ifr_flags & IFF_UP)) {
               stop_vif(vifi);
               v->uv_flags |= VIFF_DOWN;
               logit(LOG_INFO, 0,
                   "%s has gone down; vif #%u taken out of service",
                   v->uv_name, vifi);
               vifs_down = TRUE;
           }
       }
   }
}

/*
* Send a probe message on vif v
*/
static void
send_probe_on_vif(struct uvif *v)
{
   char *p;
   int datalen = 0;
   struct listaddr *nbr;
   int i;

   p = send_buf + MIN_IP_HEADER_LEN + IGMP_MINLEN;

   for (i = 0; i < 4; i++)
       *p++ = ((char *)&(dvmrp_genid))[i];
   datalen += 4;

   /*
    * add the neighbor list on the interface to the message
    */
   nbr = v->uv_neighbors;

   while (nbr) {
       for (i = 0; i < 4; i++)
           *p++ = ((char *)&nbr->al_addr)[i];
       datalen +=4;
       nbr = nbr->al_next;
   }

   send_igmp(v->uv_lcl_addr,
             (v->uv_flags & VIFF_TUNNEL) ? v->uv_rmt_addr
             : dvmrp_group,
             IGMP_DVMRP, DVMRP_PROBE,
             htonl(MROUTED_LEVEL |
             ((v->uv_flags & VIFF_LEAF) ? 0 : LEAF_FLAGS)),
             datalen);
}

/*
* Add a vifi to the kernel and start routing on it.
*/
static void
start_vif(vifi_t vifi)
{
   /*
    * Install the interface in the kernel's vif structure.
    */
   k_add_vif(vifi, &uvifs[vifi]);

   start_vif2(vifi);
}

/*
* Add a vifi to all the user-level data structures but don't add
* it to the kernel yet.
*/
static void
start_vif2(vifi_t vifi)
{
   struct uvif *v;
   u_int32_t src;
   struct phaddr *p;

   v   = &uvifs[vifi];
   src = v->uv_lcl_addr;

   /*
    * Update the existing route entries to take into account the new vif.
    */
   add_vif_to_routes(vifi);

   if (!(v->uv_flags & VIFF_TUNNEL)) {
       /*
        * Join the DVMRP multicast group on the interface.
        * (This is not strictly necessary, since the kernel promiscuously
        * receives IGMP packets addressed to ANY IP multicast group while
        * multicast routing is enabled.  However, joining the group allows
        * this host to receive non-IGMP packets as well, such as 'pings'.)
        */
       k_join(dvmrp_group, src);

       /*
        * Join the ALL-ROUTERS multicast group on the interface.
        * This allows mtrace requests to loop back if they are run
        * on the multicast router.
        */
       k_join(allrtrs_group, src);

       /*
        * Install an entry in the routing table for the subnet to which
        * the interface is connected.
        */
       start_route_updates();
       update_route(v->uv_subnet, v->uv_subnetmask, 0, 0, vifi);
       for (p = v->uv_addrs; p; p = p->pa_next) {
           start_route_updates();
           update_route(p->pa_subnet, p->pa_subnetmask, 0, 0, vifi);
       }

       /*
        * Until neighbors are discovered, assume responsibility for sending
        * periodic group membership queries to the subnet.  Send the first
        * query.
        */
       v->uv_flags |= VIFF_QUERIER;
       send_igmp(src, allhosts_group, IGMP_HOST_MEMBERSHIP_QUERY,
             (v->uv_flags & VIFF_IGMPV1) ? 0 :
             IGMP_MAX_HOST_REPORT_DELAY * IGMP_TIMER_SCALE, 0, 0);
       age_old_hosts();
   }

   v->uv_leaf_timer = LEAF_CONFIRMATION_TIME;

   /*
    * Send a probe via the new vif to look for neighbors.
    */
   send_probe_on_vif(v);
}

/*
* Stop routing on the specified virtual interface.
*/
static void
stop_vif(vifi_t vifi)
{
   struct uvif *v;
   struct listaddr *a;
   struct phaddr *p;

   v = &uvifs[vifi];

   if (!(v->uv_flags & VIFF_TUNNEL)) {
       /*
        * Depart from the DVMRP multicast group on the interface.
        */
       k_leave(dvmrp_group, v->uv_lcl_addr);

       /*
        * Depart from the ALL-ROUTERS multicast group on the interface.
        */
       k_leave(allrtrs_group, v->uv_lcl_addr);

       /*
        * Update the entry in the routing table for the subnet to which
        * the interface is connected, to take into account the interface
        * failure.
        */
       start_route_updates();
       update_route(v->uv_subnet, v->uv_subnetmask, UNREACHABLE, 0, vifi);
       for (p = v->uv_addrs; p; p = p->pa_next) {
           start_route_updates();
           update_route(p->pa_subnet, p->pa_subnetmask, UNREACHABLE, 0, vifi);
       }

       /*
        * Discard all group addresses.  (No need to tell kernel;
        * the k_del_vif() call, below, will clean up kernel state.)
        */
       while (v->uv_groups != NULL) {
           a = v->uv_groups;
           v->uv_groups = a->al_next;
           free((char *)a);
       }

       v->uv_flags &= ~VIFF_QUERIER;
   }

   /*
    * Update the existing route entries to take into account the vif failure.
    */
   delete_vif_from_routes(vifi);

   /*
    * Delete the interface from the kernel's vif structure.
    */
   k_del_vif(vifi);

   /*
    * Discard all neighbor addresses.
    */
   if (v->uv_neighbors)
       vifs_with_neighbors--;

   while (v->uv_neighbors != NULL) {
       a = v->uv_neighbors;
       v->uv_neighbors = a->al_next;
       free((char *)a);
   }
}


/*
* stop routing on all vifs
*/
void
stop_all_vifs(void)
{
   vifi_t vifi;
   struct uvif *v;
   struct listaddr *a;
   struct vif_acl *acl;

   for (vifi = 0; vifi < numvifs; vifi++) {
       v = &uvifs[vifi];
       while (v->uv_groups != NULL) {
           a = v->uv_groups;
           v->uv_groups = a->al_next;
           free((char *)a);
       }
       while (v->uv_neighbors != NULL) {
           a = v->uv_neighbors;
           v->uv_neighbors = a->al_next;
           free((char *)a);
       }
       while (v->uv_acl != NULL) {
           acl = v->uv_acl;
           v->uv_acl = acl->acl_next;
           free((char *)acl);
       }
   }
}


/*
* Find the virtual interface from which an incoming packet arrived,
* based on the packet's source and destination IP addresses.
*/
vifi_t
find_vif(u_int32_t src, u_int32_t dst)
{
   vifi_t vifi;
   struct uvif *v;
   struct phaddr *p;

   for (vifi = 0, v = uvifs; vifi < numvifs; ++vifi, ++v) {
       if (!(v->uv_flags & (VIFF_DOWN|VIFF_DISABLED))) {
           if (v->uv_flags & VIFF_TUNNEL) {
               if (src == v->uv_rmt_addr && dst == v->uv_lcl_addr)
                   return(vifi);
           }
           else {
               if ((src & v->uv_subnetmask) == v->uv_subnet &&
                   ((v->uv_subnetmask == 0xffffffff) ||
                    (src != v->uv_subnetbcast)))
                   return(vifi);
               for (p=v->uv_addrs; p; p=p->pa_next) {
                   if ((src & p->pa_subnetmask) == p->pa_subnet &&
                       ((p->pa_subnetmask == 0xffffffff) ||
                        (src != p->pa_subnetbcast)))
                       return(vifi);
               }
           }
       }
   }
   return (NO_VIF);
}

static void
age_old_hosts(void)
{
   vifi_t vifi;
   struct uvif *v;
   struct listaddr *g;

   /*
    * Decrement the old-hosts-present timer for each
    * active group on each vif.
    */
   for (vifi = 0, v = uvifs; vifi < numvifs; vifi++, v++)
       for (g = v->uv_groups; g != NULL; g = g->al_next)
           if (g->al_old)
               g->al_old--;
}


/*
* Send group membership queries to all subnets for which I am querier.
*/
void
query_groups(void)
{
   vifi_t vifi;
   struct uvif *v;

   for (vifi = 0, v = uvifs; vifi < numvifs; vifi++, v++) {
       if (v->uv_flags & VIFF_QUERIER) {
           send_igmp(v->uv_lcl_addr, allhosts_group,
                     IGMP_HOST_MEMBERSHIP_QUERY,
                     (v->uv_flags & VIFF_IGMPV1) ? 0 :
                     IGMP_MAX_HOST_REPORT_DELAY * IGMP_TIMER_SCALE, 0, 0);
       }
   }
   age_old_hosts();
}

/*
* Process an incoming host membership query
*/
void
accept_membership_query(u_int32_t src, u_int32_t dst, u_int32_t group, int tmo)
{
   vifi_t vifi;
   struct uvif *v;

   if ((vifi = find_vif(src, dst)) == NO_VIF ||
       (uvifs[vifi].uv_flags & VIFF_TUNNEL)) {
       logit(LOG_INFO, 0,
           "ignoring group membership query from non-adjacent host %s",
           inet_fmt(src));
       return;
   }

   v = &uvifs[vifi];

   /*
    * If we consider ourselves the querier for this vif, but hear a
    * query from a router with a lower IP address, yield to them.
    *
    * This is done here as well as in the neighbor discovery in case
    * there is a querier that doesn't speak DVMRP.
    *
    * XXX If this neighbor doesn't speak DVMRP, then we need to create
    * some neighbor state for him so that we can time him out!
    */
   if ((v->uv_flags & VIFF_QUERIER) &&
       (ntohl(src) < ntohl(v->uv_lcl_addr))) {
           v->uv_flags &= ~VIFF_QUERIER;

   }
}

/*
* Process an incoming group membership report.
*/
void
accept_group_report(u_int32_t src, u_int32_t dst, u_int32_t group, int r_type)
{
   vifi_t vifi;
   struct uvif *v;
   struct listaddr *g;

   if ((vifi = find_vif(src, dst)) == NO_VIF ||
       (uvifs[vifi].uv_flags & VIFF_TUNNEL)) {
       logit(LOG_INFO, 0,
           "ignoring group membership report from non-adjacent host %s",
           inet_fmt(src));
       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 (r_type == IGMP_v1_HOST_MEMBERSHIP_REPORT)
               g->al_old = OLD_AGE_THRESHOLD;
#ifdef SNMP
           g->al_genid = src;
#endif /* SNMP */

           /** delete old timers, set a timer for expiration **/
           g->al_timer = GROUP_EXPIRE_TIME;
           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);
           break;
       }
   }

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

       g->al_addr   = group;
       if (r_type == IGMP_v2_HOST_MEMBERSHIP_REPORT)
           g->al_old = 0;
       else
           g->al_old = OLD_AGE_THRESHOLD;
#ifdef SNMP
       g->al_genid = src;
#endif

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

       update_lclgrp(vifi, group);
   }

   /*
    * Check if a graft is necessary for this group
    */
   chkgrp_graft(vifi, group);
}


void
accept_leave_message(u_int32_t src, u_int32_t dst, u_int32_t group)
{
   vifi_t vifi;
   struct uvif *v;
   struct listaddr *g;

   if ((vifi = find_vif(src, dst)) == NO_VIF ||
       (uvifs[vifi].uv_flags & VIFF_TUNNEL)) {
       logit(LOG_INFO, 0,
           "ignoring group leave report from non-adjacent host %s",
           inet_fmt(src));
       return;
   }

   v = &uvifs[vifi];

   if (!(v->uv_flags & VIFF_QUERIER) || (v->uv_flags & VIFF_IGMPV1))
       return;

   /*
    * 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) {
           logit(LOG_DEBUG, 0,
               "[vif.c, _accept_leave_message] %d %ld\n",
               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);

           /** send a group specific querry **/
           g->al_timer = LEAVE_EXPIRE_TIME;
           send_igmp(v->uv_lcl_addr, g->al_addr,
                     IGMP_HOST_MEMBERSHIP_QUERY,
                     LEAVE_EXPIRE_TIME / 3 * IGMP_TIMER_SCALE,
                     g->al_addr, 0);
           g->al_query = SetQueryTimer(g, vifi, g->al_timer / 3,
                               LEAVE_EXPIRE_TIME / 3 * IGMP_TIMER_SCALE);
           g->al_timerid = SetTimer(vifi, g);
           break;
       }
   }
}


/*
* Send a periodic probe on all vifs.
* Useful to determine one-way interfaces.
* Detect neighbor loss faster.
*/
void
probe_for_neighbors(void)
{
   vifi_t vifi;
   struct uvif *v;

   for (vifi = 0, v = uvifs; vifi < numvifs; vifi++, v++) {
       if (!(v->uv_flags & (VIFF_DOWN|VIFF_DISABLED))) {
           send_probe_on_vif(v);
       }
   }
}


/*
* Send a list of all of our neighbors to the requestor, `src'.
*/
void
accept_neighbor_request(u_int32_t src, u_int32_t dst)
{
   vifi_t vifi;
   struct uvif *v;
   u_char *p, *ncount;
   struct listaddr *la;
   int datalen;
   u_int32_t temp_addr, us, them = src;

   /* Determine which of our addresses to use as the source of our response
    * to this query.
    */
   if (IN_MULTICAST(ntohl(dst))) { /* query sent to a multicast group */
       int udp;                /* find best interface to reply on */
       struct sockaddr_in addr;
       socklen_t addrlen = sizeof(addr);

       memset(&addr, 0, sizeof(addr));
       addr.sin_family = AF_INET;
#if (defined(BSD) && (BSD >= 199103))
       addr.sin_len = sizeof addr;
#endif
       addr.sin_addr.s_addr = dst;
       addr.sin_port = htons(2000); /* any port over 1024 will do... */
       if ((udp = socket(AF_INET, SOCK_DGRAM, 0)) < 0
           || connect(udp, (struct sockaddr *) &addr, sizeof(addr)) < 0
           || getsockname(udp, (struct sockaddr *) &addr, &addrlen) < 0) {
           logit(LOG_WARNING, errno, "Determining local address");
           close(udp);
           return;
       }
       close(udp);
       us = addr.sin_addr.s_addr;
   } else                      /* query sent to us alone */
       us = dst;

#define PUT_ADDR(a)     temp_addr = ntohl(a); \
                       *p++ = temp_addr >> 24; \
                       *p++ = (temp_addr >> 16) & 0xFF; \
                       *p++ = (temp_addr >> 8) & 0xFF; \
                       *p++ = temp_addr & 0xFF;

   p = (u_char *) (send_buf + MIN_IP_HEADER_LEN + IGMP_MINLEN);
   datalen = 0;

   for (vifi = 0, v = uvifs; vifi < numvifs; vifi++, v++) {
       if (v->uv_flags & VIFF_DISABLED)
           continue;

       ncount = 0;

       for (la = v->uv_neighbors; la; la = la->al_next) {

           /* Make sure that there's room for this neighbor... */
           if (datalen + (ncount == 0 ? 4 + 3 + 4 : 4) > MAX_DVMRP_DATA_LEN) {
               send_igmp(us, them, IGMP_DVMRP, DVMRP_NEIGHBORS,
                         htonl(MROUTED_LEVEL), datalen);
               p = (u_char *) (send_buf + MIN_IP_HEADER_LEN + IGMP_MINLEN);
               datalen = 0;
               ncount = 0;
           }

           /* Put out the header for this neighbor list... */
           if (ncount == 0) {
               PUT_ADDR(v->uv_lcl_addr);
               *p++ = v->uv_metric;
               *p++ = v->uv_threshold;
               ncount = p;
               *p++ = 0;
               datalen += 4 + 3;
           }

           PUT_ADDR(la->al_addr);
           datalen += 4;
           (*ncount)++;
       }
   }

   if (datalen != 0)
       send_igmp(us, them, IGMP_DVMRP, DVMRP_NEIGHBORS, htonl(MROUTED_LEVEL),
                 datalen);
}

/*
* Send a list of all of our neighbors to the requestor, `src'.
*/
void
accept_neighbor_request2(u_int32_t src, u_int32_t dst)
{
   vifi_t vifi;
   struct uvif *v;
   u_char *p, *ncount;
   struct listaddr *la;
   int datalen;
   u_int32_t us, them = src;

   /* Determine which of our addresses to use as the source of our response
    * to this query.
    */
   if (IN_MULTICAST(ntohl(dst))) { /* query sent to a multicast group */
       int udp;                /* find best interface to reply on */
       struct sockaddr_in addr;
       socklen_t addrlen = sizeof(addr);

       memset(&addr, 0, sizeof(addr));
       addr.sin_family = AF_INET;
#if (defined(BSD) && (BSD >= 199103))
       addr.sin_len = sizeof addr;
#endif
       addr.sin_addr.s_addr = dst;
       addr.sin_port = htons(2000); /* any port over 1024 will do... */
       if ((udp = socket(AF_INET, SOCK_DGRAM, 0)) < 0
           || connect(udp, (struct sockaddr *) &addr, sizeof(addr)) < 0
           || getsockname(udp, (struct sockaddr *) &addr, &addrlen) < 0) {
           logit(LOG_WARNING, errno, "Determining local address");
           close(udp);
           return;
       }
       close(udp);
       us = addr.sin_addr.s_addr;
   } else                      /* query sent to us alone */
       us = dst;

   p = (u_char *) (send_buf + MIN_IP_HEADER_LEN + IGMP_MINLEN);
   datalen = 0;

   for (vifi = 0, v = uvifs; vifi < numvifs; vifi++, v++) {
       u_short vflags = v->uv_flags;
       u_char rflags = 0;
       if (vflags & VIFF_TUNNEL)
           rflags |= DVMRP_NF_TUNNEL;
       if (vflags & VIFF_SRCRT)
           rflags |= DVMRP_NF_SRCRT;
       if (vflags & VIFF_DOWN)
           rflags |= DVMRP_NF_DOWN;
       if (vflags & VIFF_DISABLED)
           rflags |= DVMRP_NF_DISABLED;
       if (vflags & VIFF_QUERIER)
           rflags |= DVMRP_NF_QUERIER;
       if (vflags & VIFF_LEAF)
           rflags |= DVMRP_NF_LEAF;
       ncount = 0;
       la = v->uv_neighbors;
       if (la == NULL) {
           /*
            * include down & disabled interfaces and interfaces on
            * leaf nets.
            */
           if (rflags & DVMRP_NF_TUNNEL)
               rflags |= DVMRP_NF_DOWN;
           if (datalen > MAX_DVMRP_DATA_LEN - 12) {
               send_igmp(us, them, IGMP_DVMRP, DVMRP_NEIGHBORS2,
                         htonl(MROUTED_LEVEL), datalen);
               p = (u_char *) (send_buf + MIN_IP_HEADER_LEN + IGMP_MINLEN);
               datalen = 0;
           }
           *(u_int*)p = v->uv_lcl_addr;
           p += 4;
           *p++ = v->uv_metric;
           *p++ = v->uv_threshold;
           *p++ = rflags;
           *p++ = 1;
           *(u_int*)p =  v->uv_rmt_addr;
           p += 4;
           datalen += 12;
       } else {
           for ( ; la; la = la->al_next) {
               /* Make sure that there's room for this neighbor... */
               if (datalen + (ncount == 0 ? 4+4+4 : 4) > MAX_DVMRP_DATA_LEN) {
                   send_igmp(us, them, IGMP_DVMRP, DVMRP_NEIGHBORS2,
                             htonl(MROUTED_LEVEL), datalen);
                   p = (u_char *) (send_buf + MIN_IP_HEADER_LEN + IGMP_MINLEN);
                   datalen = 0;
                   ncount = 0;
               }
               /* Put out the header for this neighbor list... */
               if (ncount == 0) {
                   *(u_int*)p = v->uv_lcl_addr;
                   p += 4;
                   *p++ = v->uv_metric;
                   *p++ = v->uv_threshold;
                   *p++ = rflags;
                   ncount = p;
                   *p++ = 0;
                   datalen += 4 + 4;
               }
               *(u_int*)p = la->al_addr;
               p += 4;
               datalen += 4;
               (*ncount)++;
           }
       }
   }
   if (datalen != 0)
       send_igmp(us, them, IGMP_DVMRP, DVMRP_NEIGHBORS2, htonl(MROUTED_LEVEL),
                 datalen);
}

void
accept_info_request(u_int32_t src, u_int32_t dst, u_char *p, int datalen)
{
   u_char *q;
   int len;
   int outlen = 0;

   q = (u_char *) (send_buf + MIN_IP_HEADER_LEN + IGMP_MINLEN);

   /* To be general, this must deal properly with breaking up over-sized
    * packets.  That implies passing a length to each function, and
    * allowing each function to request to be called again.  Right now,
    * we're only implementing the one thing we are positive will fit into
    * a single packet, so we wimp out.
    */
   while (datalen > 0) {
       len = 0;
       switch (*p) {
           case DVMRP_INFO_VERSION:
               len = info_version((char *)q,
                   send_buflen - MIN_IP_HEADER_LEN - IGMP_MINLEN);
               break;

           case DVMRP_INFO_NEIGHBORS:
           default:
               logit(LOG_INFO, 0, "ignoring unknown info type %d", *p);
               break;
       }
       *(q+1) = len++;
       outlen += len * 4;
       q += len * 4;
       len = (*(p+1) + 1) * 4;
       p += len;
       datalen -= len;
   }

   if (outlen != 0)
       send_igmp(INADDR_ANY, src, IGMP_DVMRP, DVMRP_INFO_REPLY,
                       htonl(MROUTED_LEVEL), outlen);
}

/*
* Information response -- return version string
*/
static int
info_version(char *p, size_t l)
{
   int len;
   extern char versionstring[];

   if (l < 4 + strlen(versionstring) + 1)
      return -1;
   p[0] = DVMRP_INFO_VERSION;
   /* skip over length */
   p[2] = 0;   /* zero out */
   p[3] = 0;   /* reserved fields */
   strlcpy(p + 4, versionstring, l - 4);

   len = strlen(versionstring);
   return ((len + 3) / 4);
}

/*
* Process an incoming neighbor-list message.
*/
void
accept_neighbors(u_int32_t src, u_int32_t dst, u_char *p, int datalen,
                u_int32_t level)
{
   logit(LOG_INFO, 0, "ignoring spurious DVMRP neighbor list from %s to %s",
       inet_fmt(src), inet_fmt(dst));
}


/*
* Process an incoming neighbor-list message.
*/
void
accept_neighbors2(u_int32_t src, u_int32_t dst, u_char *p, int datalen,
                 u_int32_t level)
{
   logit(LOG_INFO, 0, "ignoring spurious DVMRP neighbor list2 from %s to %s",
       inet_fmt(src), inet_fmt(dst));
}

/*
* Process an incoming info reply message.
*/
void
accept_info_reply(u_int32_t src, u_int32_t dst, u_char *p, int datalen)
{
   logit(LOG_INFO, 0, "ignoring spurious DVMRP info reply from %s to %s",
       inet_fmt(src), inet_fmt(dst));
}


/*
* Update the neighbor entry for neighbor 'addr' on vif 'vifi'.
* 'msgtype' is the type of DVMRP message received from the neighbor.
* Return TRUE if 'addr' is a valid neighbor, FALSE otherwise.
*/
int
update_neighbor(vifi_t vifi, u_int32_t addr, int msgtype, char *p, int datalen, u_int32_t level)
{
   struct uvif *v;
   struct listaddr *n;
   u_int32_t genid = 0;
   u_int32_t router;
   u_int32_t send_tables = 0;
   int do_reset = FALSE;
   int nflags;

   v = &uvifs[vifi];
   nflags = (level >> 16) & 0xff;

   /*
    * Confirm that 'addr' is a valid neighbor address on vif 'vifi'.
    * IT IS ASSUMED that this was preceded by a call to find_vif(), which
    * checks that 'addr' is either a valid remote tunnel endpoint or a
    * non-broadcast address belonging to a directly-connected subnet.
    * Therefore, here we check only that 'addr' is not our own address
    * (due to an impostor or erroneous loopback) or an address of the form
    * {subnet,0} ("the unknown host").  These checks are not performed in
    * find_vif() because those types of address are acceptable for some
    * types of IGMP message (such as group membership reports).
    */
   if (!(v->uv_flags & VIFF_TUNNEL) &&
       (addr == v->uv_lcl_addr ||
        addr == v->uv_subnet )) {
       logit(LOG_WARNING, 0,
           "received DVMRP message from 'the unknown host' or self: %s",
           inet_fmt(addr));
       return (FALSE);
   }

   /*
    * Look for addr in list of neighbors.
    */
   for (n = v->uv_neighbors; n != NULL; n = n->al_next) {
       if (addr == n->al_addr) {
           break;
       }
   }

   /*
    * Found it.  Reset its timer, and check for a version change
    */
   if (n) {
       n->al_timer = 0;

       /*
        * update the neighbors version and protocol number
        * if changed => router went down and came up,
        * so take action immediately.
        */
       if ((n->al_pv != (level & 0xff)) ||
           (n->al_mv != ((level >> 8) & 0xff))) {

           do_reset = TRUE;
           logit(LOG_DEBUG, 0,
               "version change neighbor %s [old:%d.%d, new:%d.%d]",
               inet_fmt(addr),
               n->al_pv, n->al_mv, level&0xff, (level >> 8) & 0xff);

           n->al_pv = level & 0xff;
           n->al_mv = (level >> 8) & 0xff;
       }
   } else {
       /*
        * If not found, add it to the list.  If the neighbor has a lower
        * IP address than me, yield querier duties to it.
        */
       logit(LOG_DEBUG, 0, "New neighbor %s on vif %d v%d.%d nf 0x%02x",
           inet_fmt(addr), vifi,
           level & 0xff, (level >> 8) & 0xff, (level >> 16) & 0xff);

       n = (struct listaddr *)malloc(sizeof(struct listaddr));
       if (n == NULL) {
           logit(LOG_ERR, 0, "ran out of memory");    /* fatal */
           return FALSE;
       }

       n->al_addr      = addr;
       n->al_pv        = level & 0xff;
       n->al_mv        = (level >> 8) & 0xff;
       n->al_genid     = 0;

       time(&n->al_ctime);
       n->al_timer     = 0;
       n->al_next      = v->uv_neighbors;

       /*
        * If we thought that we had no neighbors on this vif, send a route
        * report to the vif.  If this is just a new neighbor on the same
        * vif, send the route report just to the new neighbor.
        */
       if (v->uv_neighbors == NULL) {
           send_tables = (v->uv_flags & VIFF_TUNNEL) ? addr : dvmrp_group;
           vifs_with_neighbors++;
       } else {
           send_tables = addr;
       }

       v->uv_neighbors = n;

       if (!(v->uv_flags & VIFF_TUNNEL) &&
           ntohl(addr) < ntohl(v->uv_lcl_addr))
           v->uv_flags &= ~VIFF_QUERIER;
   }

   /*
    * Check if the router gen-ids are the same.
    * Need to reset the prune state of the router if not.
    * Also check for one-way interfaces by seeing if we are in our
    * neighbor's list of known routers.
    */
   if (msgtype == DVMRP_PROBE) {

       /* Check genid neighbor flag.  Also check version number; 3.3 and
        * 3.4 didn't set this flag. */
       if ((((level >> 16) & 0xff) & NF_GENID) ||
           (((level & 0xff) == 3) && (((level >> 8) & 0xff) > 2))) {

           int i;

           if (datalen < 4) {
               logit(LOG_WARNING, 0,
                   "received truncated probe message from %s (len %d)",
                   inet_fmt(addr), datalen);
               return (FALSE);
           }

           for (i = 0; i < 4; i++)
             ((char *)&genid)[i] = *p++;
           datalen -= 4;

           if (n->al_genid == 0)
               n->al_genid = genid;
           else if (n->al_genid != genid) {
               logit(LOG_DEBUG, 0,
                   "new genid neigbor %s on vif %d [old:%x, new:%x]",
                   inet_fmt(addr), vifi, n->al_genid, genid);

               n->al_genid = genid;
               do_reset = TRUE;
           }

           /*
            * loop through router list and check for one-way ifs.
            */

           v->uv_flags |= VIFF_ONEWAY;

           while (datalen > 0) {
               if (datalen < 4) {
                   logit(LOG_WARNING, 0,
                       "received truncated probe message from %s (len %d)",
                       inet_fmt(addr), datalen);
                   return (FALSE);
               }
               for (i = 0; i < 4; i++)
                 ((char *)&router)[i] = *p++;
               datalen -= 4;
               if (router == v->uv_lcl_addr) {
                   v->uv_flags &= ~VIFF_ONEWAY;
                   break;
               }
           }
       }
   }
   if (n->al_flags != nflags) {
       n->al_flags = nflags;

       if (n->al_flags & NF_LEAF) {
           /*XXX If we have non-leaf neighbors then we know we shouldn't
            * mark this vif as a leaf.  For now we just count on other
            * probes and/or reports resetting the timer. */
           if (!v->uv_leaf_timer)
               v->uv_leaf_timer = LEAF_CONFIRMATION_TIME;
       } else {
           /* If we get a leaf to non-leaf transition, we *must* update
            * the routing table. */
           if (v->uv_flags & VIFF_LEAF && send_tables == 0)
               send_tables = addr;
           v->uv_flags &= ~VIFF_LEAF;
           v->uv_leaf_timer = 0;
       }
   }
   if (do_reset) {
       reset_neighbor_state(vifi, addr);
       if (!send_tables)
           send_tables = addr;
   }
   if (send_tables)
       report(ALL_ROUTES, vifi, send_tables);

   return (TRUE);
}


/*
* On every timer interrupt, advance the timer in each neighbor and
* group entry on every vif.
*/
void
age_vifs(void)
{
   vifi_t vifi;
   struct uvif *v;
   struct listaddr *a, *prev_a, *n;
   u_int32_t addr;

   for (vifi = 0, v = uvifs; vifi < numvifs; ++vifi, ++v ) {
       if (v->uv_leaf_timer && (v->uv_leaf_timer -= TIMER_INTERVAL == 0)) {
               v->uv_flags |= VIFF_LEAF;
       }

       for (prev_a = NULL, a = v->uv_neighbors; a != NULL;) {

           if ((a->al_timer += TIMER_INTERVAL) < NEIGHBOR_EXPIRE_TIME) {
               prev_a = a;
               a = a->al_next;
               continue;
           }

           /*
            * Neighbor has expired; delete it from the neighbor list,
            * delete it from the 'dominants' and 'subordinates arrays of
            * any route entries and assume querier duties unless there is
            * another neighbor with a lower IP address than mine.
            */
           addr = a->al_addr;
           if (a == v->uv_neighbors) { /* implies prev_a == NULL */
               v->uv_neighbors = a->al_next;
               free((char *)a);
               a = v->uv_neighbors;    /* prev_a stays NULL */
           } else {
               prev_a->al_next = a->al_next;
               free((char *)a);
               a = prev_a->al_next;    /* prev_a stays the same */
           }

           delete_neighbor_from_routes(addr, vifi);

           if (v->uv_neighbors == NULL)
               vifs_with_neighbors--;

           v->uv_leaf_timer = LEAF_CONFIRMATION_TIME;

           if (!(v->uv_flags & VIFF_TUNNEL)) {
               v->uv_flags |= VIFF_QUERIER;
               for (n = v->uv_neighbors; n != NULL; n = n->al_next) {
                   if (ntohl(n->al_addr) < ntohl(v->uv_lcl_addr)) {
                       v->uv_flags &= ~VIFF_QUERIER;
                   }
                   if (!(n->al_flags & NF_LEAF)) {
                       v->uv_leaf_timer = 0;
                   }
               }
           }
       }
   }
}

/*
* Returns the neighbor info struct for a given neighbor
*/
struct listaddr *
neighbor_info(vifi_t vifi, u_int32_t addr)
{
   struct listaddr *u;

   for (u = uvifs[vifi].uv_neighbors; u; u = u->al_next)
       if (u->al_addr == addr)
           return u;

   return NULL;
}

/*
* Print the contents of the uvifs array on file 'fp'.
*/
void
dump_vifs(FILE *fp)
{
   vifi_t vifi;
   struct uvif *v;
   struct listaddr *a;
   struct phaddr *p;
   struct sioc_vif_req v_req;

   fprintf(fp, "vifs_with_neighbors = %d\n", vifs_with_neighbors);

   if (vifs_with_neighbors == 1)
       fprintf(fp,"[This host is a leaf]\n\n");

   fprintf(fp,
   "\nVirtual Interface Table\n%s",
   "Vif  Name  Local-Address                               ");
   fprintf(fp,
   "M  Thr  Rate   Flags\n");

   for (vifi = 0, v = uvifs; vifi < numvifs; vifi++, v++) {

       fprintf(fp, "%2u %6s  %-15s %6s: %-18s %2u %3u  %5u  ",
               vifi,
               v->uv_name,
               inet_fmt(v->uv_lcl_addr),
               (v->uv_flags & VIFF_TUNNEL) ?
                       "tunnel":
                       "subnet",
               (v->uv_flags & VIFF_TUNNEL) ?
                       inet_fmt(v->uv_rmt_addr) :
                       inet_fmts(v->uv_subnet, v->uv_subnetmask),
               v->uv_metric,
               v->uv_threshold,
               v->uv_rate_limit);

       if (v->uv_flags & VIFF_ONEWAY)   fprintf(fp, " one-way");
       if (v->uv_flags & VIFF_DOWN)     fprintf(fp, " down");
       if (v->uv_flags & VIFF_DISABLED) fprintf(fp, " disabled");
       if (v->uv_flags & VIFF_QUERIER)  fprintf(fp, " querier");
       if (v->uv_flags & VIFF_SRCRT)    fprintf(fp, " src-rt");
       if (v->uv_flags & VIFF_LEAF)     fprintf(fp, " leaf");
       if (v->uv_flags & VIFF_IGMPV1)   fprintf(fp, " IGMPv1");
       fprintf(fp, "\n");

       if (v->uv_addrs != NULL) {
           fprintf(fp, "                alternate subnets: %s\n",
                   inet_fmts(v->uv_addrs->pa_subnet,
                   v->uv_addrs->pa_subnetmask));
           for (p = v->uv_addrs->pa_next; p; p = p->pa_next) {
               fprintf(fp, "                                   %s\n",
                       inet_fmts(p->pa_subnet, p->pa_subnetmask));
           }
       }

       if (v->uv_neighbors != NULL) {
           fprintf(fp, "                            peers: %s (%d.%d) (0x%x)\n",
                   inet_fmt(v->uv_neighbors->al_addr),
                   v->uv_neighbors->al_pv, v->uv_neighbors->al_mv,
                   v->uv_neighbors->al_flags);
           for (a = v->uv_neighbors->al_next; a != NULL; a = a->al_next) {
               fprintf(fp, "                                   %s (%d.%d) (0x%x)\n",
                       inet_fmt(a->al_addr), a->al_pv,
                       a->al_mv, a->al_flags);
           }
       }

       if (v->uv_groups != NULL) {
           fprintf(fp, "                           groups: %-15s\n",
                   inet_fmt(v->uv_groups->al_addr));
           for (a = v->uv_groups->al_next; a != NULL; a = a->al_next) {
               fprintf(fp, "                                   %-15s\n",
                       inet_fmt(a->al_addr));
           }
       }
       if (v->uv_acl != NULL) {
           struct vif_acl *acl;

           fprintf(fp, "                       boundaries: %-18s\n",
                   inet_fmts(v->uv_acl->acl_addr, v->uv_acl->acl_mask));
           for (acl = v->uv_acl->acl_next; acl != NULL; acl = acl->acl_next) {
               fprintf(fp, "                                 : %-18s\n",
                       inet_fmts(acl->acl_addr, acl->acl_mask));
           }
       }
       v_req.vifi = vifi;
       if (ioctl(igmp_socket, SIOCGETVIFCNT, (char *)&v_req) < 0) {
           logit(LOG_WARNING, 0,
               "SIOCGETVIFCNT fails");
       }
       else {
           fprintf(fp, "                         pkts in : %ld\n",
                   v_req.icount);
           fprintf(fp, "                         pkts out: %ld\n",
                   v_req.ocount);
       }
       fprintf(fp, "\n");
   }
   fprintf(fp, "\n");
}

/*
* 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_lclgrp(vifi, 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 *) malloc(sizeof(cbk_t));
   cbk->g = g;
   cbk->vifi = vifi;
   return timer_setTimer(g->al_timer, (cfunc_t)DelVif, (void *)cbk);
}

/*
* Delete a timer that was set above.
*/
static int
DeleteTimer(int id)
{
   timer_clearTimer(id);
   return 0;
}

/*
* Send a group-specific query.
*/
static void
SendQuery(void *arg)
{
   cbk_t *cbk = (cbk_t *)arg;
   struct uvif *v = &uvifs[cbk->vifi];

   send_igmp(v->uv_lcl_addr, cbk->g->al_addr,
             IGMP_HOST_MEMBERSHIP_QUERY,
             cbk->q_time, cbk->g->al_addr, 0);
   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 *) malloc(sizeof(cbk_t));
   cbk->g = g;
   cbk->q_time = q_time;
   cbk->vifi = vifi;
   return timer_setTimer(to_expire, (cfunc_t)SendQuery, (void *)cbk);
}