ripd.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

	      {
		/* If the route is not connected or localy generated
		   one, use default-metric value*/
		if (rinfo->type != ZEBRA_ROUTE_RIP 
		    && rinfo->type != ZEBRA_ROUTE_CONNECT
		    && rinfo->metric != RIP_METRIC_INFINITY)
		  rinfo->metric_out = rip->default_metric;
	      }
	  }

	/* Apply offset-list */
	if (rinfo->metric != RIP_METRIC_INFINITY)
	  rip_offset_list_apply_out (p, ifp, &rinfo->metric_out);

	if (rinfo->metric_out > RIP_METRIC_INFINITY)
	  rinfo->metric_out = RIP_METRIC_INFINITY;
	  
	/* Write RTE to the stream. */
	num = rip_write_rte (num, s, p, version, rinfo, to ? NULL : ifp);
	if (num == rtemax)
	  {
	    if (version == RIPv2 && ri->auth_type == RIP_AUTH_MD5)
	      rip_auth_md5_set (s, ifp);

	    ret = rip_send_packet (STREAM_DATA (s), stream_get_endp (s),
				   to, ifp);

	    if (ret >= 0 && IS_RIP_DEBUG_SEND)
	      rip_packet_dump ((struct rip_packet *)STREAM_DATA (s),
			       stream_get_endp(s), "SEND");
	    num = 0;
	    stream_reset (s);
	  }
      }

  /* Flush unwritten RTE. */
  if (num != 0)
    {
      if (version == RIPv2 && ri->auth_type == RIP_AUTH_MD5)
	rip_auth_md5_set (s, ifp);

      ret = rip_send_packet (STREAM_DATA (s), stream_get_endp (s), to, ifp);

      if (ret >= 0 && IS_RIP_DEBUG_SEND)
	rip_packet_dump ((struct rip_packet *)STREAM_DATA (s),
			 stream_get_endp (s), "SEND");
      num = 0;
      stream_reset (s);
    }

  /* Statistics updates. */
  ri->sent_updates++;
}

/* Send RIP packet to the interface. */
void
rip_update_interface (struct interface *ifp, u_char version, int route_type)
{
  struct prefix_ipv4 *p;
  struct connected *connected;
  listnode node;
  struct sockaddr_in to;

  /* When RIP version is 2 and multicast enable interface. */
  if (version == RIPv2 && if_is_multicast (ifp)) 
    {
      if (IS_RIP_DEBUG_EVENT)
	zlog_info ("multicast announce on %s ", ifp->name);

      rip_output_process (ifp, NULL, route_type, version);
      return;
    }

  /* If we can't send multicast packet, send it with unicast. */
  if (if_is_broadcast (ifp) || if_is_pointopoint (ifp))
    {
      for (node = listhead (ifp->connected); node; nextnode (node))
	{	    
	  connected = getdata (node);

	  /* Fetch broadcast address or poin-to-point destination
             address . */
	  p = (struct prefix_ipv4 *) connected->destination;

	  if (p->family == AF_INET)
	    {
	      /* Destination address and port setting. */
	      memset (&to, 0, sizeof (struct sockaddr_in));
	      to.sin_addr = p->prefix;
	      to.sin_port = htons (RIP_PORT_DEFAULT);

	      if (IS_RIP_DEBUG_EVENT)
		zlog_info ("%s announce to %s on %s",
			   if_is_pointopoint (ifp) ? "unicast" : "broadcast",
			   inet_ntoa (to.sin_addr), ifp->name);

	      rip_output_process (ifp, &to, route_type, version);
	    }
	}
    }
}

/* Update send to all interface and neighbor. */
void
rip_update_process (int route_type)
{
  listnode node;
  struct interface *ifp;
  struct rip_interface *ri;
  struct route_node *rp;
  struct sockaddr_in to;
  struct prefix_ipv4 *p;

  /* Send RIP update to each interface. */
  for (node = listhead (iflist); node; nextnode (node))
    {
      ifp = getdata (node);

      if (if_is_loopback (ifp))
	continue;

      if (! if_is_up (ifp))
	continue;

      /* Fetch RIP interface information. */
      ri = ifp->info;

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

      if (ri->running)
	{
	  if (IS_RIP_DEBUG_EVENT) 
	    {
	      if (ifp->name) 
		zlog_info ("SEND UPDATE to %s ifindex %d",
			   ifp->name, ifp->ifindex);
	      else
		zlog_info ("SEND UPDATE to _unknown_ ifindex %d",
			   ifp->ifindex);
	    }

	  /* If there is no version configuration in the interface,
             use rip's version setting. */
	  if (ri->ri_send == RI_RIP_UNSPEC)
	    {
	      if (rip->version == RIPv1)
		rip_update_interface (ifp, RIPv1, route_type);
	      else
		rip_update_interface (ifp, RIPv2, route_type);
	    }
	  /* If interface has RIP version configuration use it. */
	  else
	    {
	      if (ri->ri_send & RIPv1)
		rip_update_interface (ifp, RIPv1, route_type);
	      if (ri->ri_send & RIPv2)
		rip_update_interface (ifp, RIPv2, route_type);
	    }
	}
    }

  /* RIP send updates to each neighbor. */
  for (rp = route_top (rip->neighbor); rp; rp = route_next (rp))
    if (rp->info != NULL)
      {
	p = (struct prefix_ipv4 *) &rp->p;

	ifp = if_lookup_address (p->prefix);
	if (! ifp)
	  {
	    zlog_warn ("Neighbor %s doesn't exist direct connected network",
		       inet_ntoa (p->prefix));
	    continue;
	  }

	/* Set destination address and port */
	memset (&to, 0, sizeof (struct sockaddr_in));
	to.sin_addr = p->prefix;
	to.sin_port = htons (RIP_PORT_DEFAULT);

	/* RIP version is rip's configuration. */
	rip_output_process (ifp, &to, route_type, rip->version);
      }
}

/* RIP's periodical timer. */
int
rip_update (struct thread *t)
{
  /* Clear timer pointer. */
  rip->t_update = NULL;

  if (IS_RIP_DEBUG_EVENT)
    zlog_info ("update timer fire!");

  /* Process update output. */
  rip_update_process (rip_all_route);

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

  /* Register myself. */
  rip_event (RIP_UPDATE_EVENT, 0);

  return 0;
}

/* Walk down the RIP routing table then clear changed flag. */
void
rip_clear_changed_flag ()
{
  struct route_node *rp;
  struct rip_info *rinfo;

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

/* Triggered update interval timer. */
int
rip_triggered_interval (struct thread *t)
{
  int rip_triggered_update (struct thread *);

  rip->t_triggered_interval = NULL;

  if (rip->trigger)
    {
      rip->trigger = 0;
      rip_triggered_update (t);
    }
  return 0;
}     

/* Execute triggered update. */
int
rip_triggered_update (struct thread *t)
{
  int interval;

  /* Clear thred pointer. */
  rip->t_triggered_update = NULL;

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

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

  /* Split Horizon processing is done when generating triggered
     updates as well as normal updates (see section 2.6). */
  rip_update_process (rip_changed_route);

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

  rip->t_triggered_interval = 
    thread_add_timer (master, rip_triggered_interval, NULL, interval);

  return 0;
}

/* Withdraw redistributed route. */
void
rip_redistribute_withdraw (int type)
{
  struct route_node *rp;
  struct rip_info *rinfo;

  if (!rip)
    return;

  for (rp = route_top (rip->table); rp; rp = route_next (rp))
    if ((rinfo = rp->info) != NULL)
      {
	if (rinfo->type == type
	    && rinfo->sub_type != RIP_ROUTE_INTERFACE)
	  {
	    /* Perform poisoned reverse. */
	    rinfo->metric = RIP_METRIC_INFINITY;
	    RIP_TIMER_ON (rinfo->t_garbage_collect, 
			  rip_garbage_collect, rip->garbage_time);
	    RIP_TIMER_OFF (rinfo->t_timeout);
	    rinfo->flags |= RIP_RTF_CHANGED;

	    rip_event (RIP_TRIGGERED_UPDATE, 0);
	  }
      }
}

/* Create new RIP instance and set it to global variable. */
int
rip_create ()
{
  rip = XMALLOC (MTYPE_RIP, sizeof (struct rip));
  memset (rip, 0, sizeof (struct rip));

  /* Set initial value. */
  rip->version = RIPv2;
  rip->update_time = RIP_UPDATE_TIMER_DEFAULT;
  rip->timeout_time = RIP_TIMEOUT_TIMER_DEFAULT;
  rip->garbage_time = RIP_GARBAGE_TIMER_DEFAULT;
  rip->default_metric = RIP_DEFAULT_METRIC_DEFAULT;

  /* Initialize RIP routig table. */
  rip->table = route_table_init ();
  rip->route = route_table_init ();
  rip->neighbor = route_table_init ();

  /* Make output stream. */
  rip->obuf = stream_new (1500);

  /* Make socket. */
  rip->sock = rip_create_socket ();
  if (rip->sock < 0)
    return rip->sock;

  /* Create read and timer thread. */
  rip_event (RIP_READ, rip->sock);
  rip_event (RIP_UPDATE_EVENT, 1);

  return 0;
}

/* Sned RIP request to the destination. */
int
rip_request_send (struct sockaddr_in *to, struct interface *ifp,
		  u_char version)
{
  struct rte *rte;
  struct rip_packet rip_packet;

  memset (&rip_packet, 0, sizeof (rip_packet));

  rip_packet.command = RIP_REQUEST;
  rip_packet.version = version;
  rte = rip_packet.rte;
  rte->metric = htonl (RIP_METRIC_INFINITY);

  return rip_send_packet ((caddr_t) &rip_packet, sizeof (rip_packet), to, ifp);
}

int
rip_update_jitter (unsigned long time)
{
  return ((rand () % (time + 1)) - (time / 2));
}

void
rip_event (enum rip_event event, int sock)
{
  int jitter = 0;

  switch (event)
    {
    case RIP_READ:
      rip->t_read = thread_add_read (master, rip_read, NULL, sock);
      break;
    case RIP_UPDATE_EVENT:
      if (rip->t_update)
	{
	  thread_cancel (rip->t_update);
	  rip->t_update = NULL;
	}
      jitter = rip_update_jitter (rip->update_time);
      rip->t_update = 
	thread_add_timer (master, rip_update, NULL, 
			  sock ? 2 : rip->update_time + jitter);
      break;
    case RIP_TRIGGERED_UPDATE:
      if (rip->t_triggered_interval)
	rip->trigger = 1;
      else if (! rip->t_triggered_update)
	rip->t_triggered_update = 
	  thread_add_event (master, rip_triggered_update, NULL, 0);
      break;
    default:
      break;
    }
}

DEFUN (router_rip,
       router_rip_cmd,
       "router rip",
       "Enable a routing process\n"
       "Routing Information Protocol (RIP)\n")
{
  int ret;

  /* If rip is not enabled before. */
  if (! rip)
    {
      ret = rip_create ();
      if (ret < 0)
	{
	  zlog_info ("Can't create RIP");
	  return CMD_WARNING;
	}
    }
  vty->node = RIP_NODE;
  vty->index = rip;

  return CMD_SUCCESS;
}

DEFUN (no_router_rip,
       no_router_rip_cmd,
       "no router rip",
       NO_STR
       "Enable a routing process\n"
       "Routing Information Protocol (RIP)\n")
{
  if (rip)
    rip_clean ();
  return CMD_SUCCESS;
}

DEFUN (rip_version,
       rip_version_cmd,
       "version <1-2>",
       "Set routing protocol version\n"
       "version\n")
{
  int version;

  version = atoi (argv[0]);
  if (version != RIPv1 && version != RIPv2)
    {
      vty_out (vty, "invalid rip version %d%s", version,
	       VTY_NEWLINE);
      return CMD_WARNING;
    }
  rip->version = version;

  return CMD_SUCCESS;
} 

DEFUN (no_rip_version,
       no_rip_version_cmd,
       "no version",
       NO_STR
       "Set routing protocol version\n")
{
  /* Set RIP version to the default. */
  rip->version = RIPv2;

  return CMD_SUCCESS;
} 

ALIAS (no_rip_version,
       no_rip_version_val_cmd,
       "no version <1-2>",
       NO_STR
       "Set routing protocol version\n"
       "version\n");

DEFUN (rip_route,
       rip_route_cmd,
       "route A.B.C.D/M",
       "RIP static route configuration\n"
       "IP prefix <network>/<length>\n")
{
  int ret;
  struct prefix_ipv4 p;
  struct route_node *node;

  ret = str2prefix_ipv4 (argv[0], &p);
  if (ret < 0)
    {
      vty_out (vty, "Malformed address%s", VTY_NEWLINE);
      return CMD_WARNING;
    }
  apply_mask_ipv4 (&p);

  /* For router rip configuration. */
  node = route_node_get (rip->route, (struct prefix *) &p);

  if (node->info)
    {
      vty_out (vty, "There is already same static route.%s", VTY_NEWLINE);
      route_unlock_node (node);
      return CMD_WARNING;
    }

  node->info = "static";

  rip_redistribute_add (ZEBRA_ROUTE_RIP, RIP_ROUTE_STATI