ripngd.c

大名鼎鼎的路由器源码。程序分ZEBRA、OSPFRIP等3个包。程序框架采用一个路由协议一个进程的方式

ripng_read (struct thread *thread)
{
  int len;
  int sock;
  struct sockaddr_in6 from;
  struct ripng_packet *packet;
  unsigned int ifindex;
  struct interface *ifp;
  int hoplimit = -1;

  /* Check ripng is active and alive. */
  assert (ripng != NULL);
  assert (ripng->sock >= 0);

  /* Fetch thread data and set read pointer to empty for event
     managing.  `sock' sould be same as ripng->sock. */
  sock = THREAD_FD (thread);
  ripng->t_read = NULL;

  /* Add myself to the next event. */
  ripng_event (RIPNG_READ, sock);

  /* Read RIPng packet. */
  len = ripng_recv_packet (sock, STREAM_DATA (ripng->ibuf), 
			   STREAM_SIZE (ripng->ibuf), &from, &ifindex,
			   &hoplimit);
  if (len < 0) 
    {
      zlog_warn ("RIPng recvfrom failed: %s.", strerror (errno));
      return len;
    }

  /* Check RTE boundary.  RTE size (Packet length - RIPng header size
     (4)) must be multiple size of one RTE size (20). */
  if (((len - 4) % 20) != 0)
    {
      zlog_warn ("RIPng invalid packet size %d from %s", len,
		 inet6_ntop (&from.sin6_addr));
      return 0;
    }

  packet = (struct ripng_packet *) STREAM_DATA (ripng->ibuf);
  ifp = if_lookup_by_index (ifindex);

  /* RIPng packet received. */
  if (IS_RIPNG_DEBUG_EVENT)
    zlog_info ("RIPng packet received from %s port %d on %s",
	       inet6_ntop (&from.sin6_addr), ntohs (from.sin6_port), 
	       ifp ? ifp->name : "unknown");

  /* Logging before packet checking. */
  if (IS_RIPNG_DEBUG_RECV)
    ripng_packet_dump (packet, len, "RECV");

  /* Packet comes from unknown interface. */
  if (ifp == NULL)
    {
      zlog_warn ("RIPng packet comes from unknown interface %d", ifindex);
      return 0;
    }

  /* Packet version mismatch checking. */
  if (packet->version != ripng->version) 
    {
      zlog_warn ("RIPng packet version %d doesn't fit to my version %d", 
		 packet->version, ripng->version);
      return 0;
    }

  /* Process RIPng packet. */
  switch (packet->command)
    {
    case RIPNG_REQUEST:
      ripng_request_process (packet, len, &from, ifp);
      break;
    case RIPNG_RESPONSE:
      ripng_response_process (packet, len, &from, ifp, hoplimit);
      break;
    default:
      zlog_warn ("Invalid RIPng command %d", packet->command);
      break;
    }
  return 0;
}

/* Walk down the RIPng routing table then clear changed flag. */
void
ripng_clear_changed_flag ()
{
  struct route_node *rp;
  struct ripng_info *rinfo;

  for (rp = route_top (ripng->table); rp; rp = route_next (rp))
    if ((rinfo = rp->info) != NULL)
      if (rinfo->flags & RIPNG_RTF_CHANGED)
	rinfo->flags &= ~RIPNG_RTF_CHANGED;
}

/* Regular update of RIPng route.  Send all routing formation to RIPng
   enabled interface. */
int
ripng_update (struct thread *t)
{
  listnode node;
  struct interface *ifp;
  struct ripng_interface *ri;

  /* Clear update timer thread. */
  ripng->t_update = NULL;

  /* Logging update event. */
  if (IS_RIPNG_DEBUG_EVENT)
    zlog_info ("RIPng update timer expired!");

  /* Supply routes to each interface. */
  for (node = listhead (iflist); node; nextnode (node))
    {
      ifp = getdata (node);
      ri = ifp->info;

      if (if_is_loopback (ifp) || ! if_is_up (ifp))
	continue;

      if (! ri->running)
	continue;

      /* When passive interface is specified, suppress announce to the
         interface. */
      if (ri->passive)
	continue;

#if RIPNG_ADVANCED
      if (ri->ri_send == RIPNG_SEND_OFF)
	{
	  if (IS_RIPNG_DEBUG_EVENT)
	    zlog (NULL, LOG_INFO, 
		  "[Event] RIPng send to if %d is suppressed by config",
		 ifp->ifindex);
	  continue;
	}
#endif /* RIPNG_ADVANCED */

      ripng_output_process (ifp, NULL, ripng_all_route, ripng_split_horizon);
    }

  /* Triggered updates may be suppressed if a regular update is due by
     the time the triggered update would be sent. */
  if (ripng->t_triggered_interval)
    {
      thread_cancel (ripng->t_triggered_interval);
      ripng->t_triggered_interval = NULL;
    }
  ripng->trigger = 0;

  /* Reset flush event. */
  ripng_event (RIPNG_UPDATE_EVENT, 0);

  return 0;
}

/* Triggered update interval timer. */
int
ripng_triggered_interval (struct thread *t)
{
  ripng->t_triggered_interval = NULL;

  if (ripng->trigger)
    {
      ripng->trigger = 0;
      ripng_triggered_update (t);
    }
  return 0;
}     

/* Execute triggered update. */
int
ripng_triggered_update (struct thread *t)
{
  listnode node;
  struct interface *ifp;
  struct ripng_interface *ri;
  int interval;

  ripng->t_triggered_update = NULL;

  /* Cancel interval timer. */
  if (ripng->t_triggered_interval)
    {
      thread_cancel (ripng->t_triggered_interval);
      ripng->t_triggered_interval = NULL;
    }
  ripng->trigger = 0;

  /* Logging triggered update. */
  if (IS_RIPNG_DEBUG_EVENT)
    zlog_info ("RIPng triggered update!");

  /* Split Horizon processing is done when generating triggered
     updates as well as normal updates (see section 2.6). */
  for (node = listhead (iflist); node; nextnode (node))
    {
      ifp = getdata (node);
      ri = ifp->info;

      if (if_is_loopback (ifp) || ! if_is_up (ifp))
	continue;

      if (! ri->running)
	continue;

      /* When passive interface is specified, suppress announce to the
         interface. */
      if (ri->passive)
	continue;

      ripng_output_process (ifp, NULL, ripng_changed_route,
			    ripng_split_horizon);
    }

  /* Once all of the triggered updates have been generated, the route
     change flags should be cleared. */
  ripng_clear_changed_flag ();

  /* After a triggered update is sent, a timer should be set for a
     random interval between 1 and 5 seconds.  If other changes that
     would trigger updates occur before the timer expires, a single
     update is triggered when the timer expires. */
  interval = (random () % 5) + 1;

  ripng->t_triggered_interval = 
    thread_add_timer (master, ripng_triggered_interval, NULL, interval);

  return 0;
}

/* Write routing table entry to the stream and return next index of
   the routing table entry in the stream. */
int
ripng_write_rte (int num, struct stream *s, struct prefix_ipv6 *p,
		 u_int16_t tag, u_char metric)
{
  /* RIPng packet header. */
  if (num == 0)
    {
      stream_putc (s, RIPNG_RESPONSE);
      stream_putc (s, RIPNG_V1);
      stream_putw (s, 0);
    }

  /* Write routing table entry. */
  stream_write (s, (caddr_t) &p->prefix, sizeof (struct in6_addr));
  stream_putw (s, tag);
  stream_putc (s, p->prefixlen);
  stream_putc (s, metric);

  return ++num;
}

/* Send RESPONSE message to specified destination. */
void
ripng_output_process (struct interface *ifp, struct sockaddr_in6 *to,
		      int route_type, int split_horizon)
{
  int ret;
  struct stream *s;
  struct route_node *rp;
  struct ripng_info *rinfo;
  struct ripng_interface *ri;
  struct ripng_aggregate *aggregate;
  struct prefix_ipv6 *p;
  int num;
  int mtu;
  int rtemax;
  u_char metric;
  u_char metric_set;

  if (IS_RIPNG_DEBUG_EVENT)
    zlog_info ("RIPng update routes on interface %s", ifp->name);

  /* Output stream get from ripng structre.  XXX this should be
     interface structure. */
  s = ripng->obuf;

  /* Reset stream and RTE counter. */
  stream_reset (s);
  num = 0;

  mtu = ifp->mtu;
  if (mtu < 0)
    mtu = IFMINMTU;

  rtemax = (min (mtu, RIPNG_MAX_PACKET_SIZE) -
	    IPV6_HDRLEN - 
	    sizeof (struct udphdr) -
	    sizeof (struct ripng_packet) +
	    sizeof (struct rte)) / sizeof (struct rte);

#ifdef DEBUG
  zlog_info ("DEBUG RIPng: ifmtu is %d", ifp->mtu);
  zlog_info ("DEBUG RIPng: rtemax is %d", rtemax);
#endif /* DEBUG */
  
  /* Get RIPng interface. */
  ri = ifp->info;
  
  for (rp = route_top (ripng->table); rp; rp = route_next (rp))
    {
      if ((rinfo = rp->info) != NULL && rinfo->suppress == 0)
	{
	  p = (struct prefix_ipv6 *) &rp->p;
	  metric = rinfo->metric;

	  /* Changed route only output. */
	  if (route_type == ripng_changed_route &&
	      (! (rinfo->flags & RIPNG_RTF_CHANGED)))
	    continue;

	  /* Split horizon. */
	  if (split_horizon == ripng_split_horizon &&
	      rinfo->ifindex == ifp->ifindex)
	    continue;
	
	  /* Apply output filters.*/
	  if (ri->list[RIPNG_FILTER_OUT])
	    {
	      if (access_list_apply (ri->list[RIPNG_FILTER_OUT], 
				     (struct prefix *) p) == FILTER_DENY)
		{
		  if (IS_RIPNG_DEBUG_PACKET)
		    zlog_info ("RIPng %s/%d is filtered by distribute out",
			       inet6_ntop (&p->prefix), p->prefixlen);
		  continue;
		}
	    }
	  if (ri->prefix[RIPNG_FILTER_OUT])
	    {
	      if (prefix_list_apply (ri->prefix[RIPNG_FILTER_OUT], 
				     (struct prefix *) p) == PREFIX_DENY)
		{
		  if (IS_RIPNG_DEBUG_PACKET)
		    zlog_info ("RIPng %s/%d is filtered by prefix-list out",
			       inet6_ntop (&p->prefix), p->prefixlen);
		  continue;
		}
	    }

	  /* Preparation for route-map. */
	  metric_set = 0;

	  /* Route-map */
	  if (ri->routemap[RIPNG_FILTER_OUT])
	    {
	      int ret;
	      struct ripng_info newinfo;

	      memset (&newinfo, 0, sizeof (struct ripng_info));
	      newinfo.metric = metric;

	      ret = route_map_apply (ri->routemap[RIPNG_FILTER_OUT], 
				     (struct prefix *) p, RMAP_RIPNG, 
				     &newinfo);

	      if (ret == RMAP_DENYMATCH)
		{
		  if (IS_RIPNG_DEBUG_PACKET)
		    zlog_info ("RIPng %s/%d is filtered by route-map out",
			       inet6_ntop (&p->prefix), p->prefixlen);
		  return;
		}

	      metric = newinfo.metric;
	      metric_set = newinfo.metric_set;
	    }

	  /* When the interface route-map does not set metric */
	  if (! metric_set)
	    {
	      /* and the redistribute route-map is set. */
	      if (ripng->route_map[rinfo->type].name)
		{
		  int ret;
		  struct ripng_info newinfo;

		  memset (&newinfo, 0, sizeof (struct ripng_info));
		  newinfo.metric = metric;
	      
		  ret = route_map_apply (ripng->route_map[rinfo->type].map,
					 (struct prefix *) p, RMAP_RIPNG,
					 &newinfo);

		  if (ret == RMAP_DENYMATCH)
		    {
		      if (IS_RIPNG_DEBUG_PACKET)
			zlog_info ("RIPng %s/%d is filtered by route-map",
				   inet6_ntop (&p->prefix), p->prefixlen);
		      continue;
		    }

		  metric = newinfo.metric;
		  metric_set = newinfo.metric_set;
		}

	      /* When the redistribute route-map does not set metric. */
	      if (! metric_set)
		{
		  /* If the redistribute metric is set. */
		  if (ripng->route_map[rinfo->type].metric_config
		      && rinfo->metric != RIPNG_METRIC_INFINITY)
		    {
		      metric = ripng->route_map[rinfo->type].metric;
		    }
		  else
		    {
		      /* If the route is not connected or localy generated
			 one, use default-metric value */
		      if (rinfo->type != ZEBRA_ROUTE_RIPNG
			  && rinfo->type != ZEBRA_ROUTE_CONNECT
			  && rinfo->metric != RIPNG_METRIC_INFINITY)
			metric = ripng->default_metric;
		    }
		}
	    }

	  /* Write RTE to the stream. */
	  num = ripng_write_rte (num, s, p, rinfo->tag, metric);
	  if (num == rtemax)
	    {
	      ret = ripng_send_packet (STREAM_DATA (s), stream_get_endp (s),
				       to, ifp);

	      if (ret >= 0 && IS_RIPNG_DEBUG_SEND)
		ripng_packet_dump ((struct ripng_packet *)STREAM_DATA (s),
				   stream_get_endp(s), "SEND");
	      num = 0;
	      stream_reset (s);
	    }
	}
      if ((aggregate = rp->aggregate) != NULL && 
	  aggregate->count > 0 && 
	  aggregate->suppress == 0)
	{
	  p = (struct prefix_ipv6 *) &rp->p;
	  metric = aggregate->metric;

	  /* Apply output filters.*/
	  if (ri->list[RIPNG_FILTER_OUT])
	    {
	      if (access_list_apply (ri->list[RIPNG_FILTER_OUT], 
				     (struct prefix *) p) == FILTER_DENY)
		{
		  if (IS_RIPNG_DEBUG_PACKET)
		    zlog_info ("RIPng %s/%d is filtered by distribute out",
			       inet6_ntop (&p->prefix), p->prefixlen);
		  continue;
		}
	    }
	  if (ri->prefix[RIPNG_FILTER_OUT])
	    {
	      if (prefix_list_apply (ri->prefix[RIPNG_FILTER_OUT], 
				     (struct prefix *) p) == PREFIX_DENY)
		{
		  if (IS_RIPNG_DEBUG_PACKET)
		    zlog_info ("RIPng %s/%d is filtered by prefix-list out",
			       inet6_ntop (&p->prefix), p->prefixlen);
		  continue;
		}
	    }

	  /* Route-map */
	  if (ri->routemap[RIPNG_FILTER_OUT])
	    {
	      int ret;
	      struct ripng_info newinfo;

	      memset (&newinfo, 0, sizeof (struct ripng_info));
	      newinfo.metric = metric;

	      ret = route_map_apply (ri->routemap[RIPNG_FILTER_OUT], 
				     (struct prefix *) p, RMAP_RIPNG, 
				     &newinfo);

	      if (ret == RMAP_DENYMATCH)
		{
		  if (IS_RIPNG_DEBUG_PACKET)
		    zlog_info ("RIPng %s/%d is filtered by route-map out",
			       inet6_ntop (&p->prefix), p->prefixlen);
		  return;
		}

	      metric = newinfo.metric;
	    }

	  /* Changed route only output. */
	  if (route_type == ripng_changed_route)
	    continue;

	  /* Write RTE to the stream. */
	  num = ripng_write_rte (num, s, p, aggregate->tag, metric);
	  if (num == rtemax)
	    {
	      ret = ripng_send_packet (STREAM_DATA (s), stream_get_endp (s),
				       to, ifp);

	      if (ret >= 0 && IS_RIPNG_DEBUG_SEND)