bgp_packet.c

linux 路由软件 可支持RIP OSPF BGP等

  /* Unfeasible Routes Length. */;
  cp = stream_get_putp (s);
  stream_putw (s, 0);

  /* Withdrawn Routes. */
  if (p.family == AF_INET && safi == SAFI_UNICAST)
    {
      stream_put_prefix (s, &p);

      unfeasible_len = stream_get_putp (s) - cp - 2;

      /* Set unfeasible len.  */
      stream_putw_at (s, cp, unfeasible_len);

      /* Set total path attribute length. */
      stream_putw (s, 0);
    }
  else
    {
      pos = stream_get_putp (s);
      stream_putw (s, 0);
      total_attr_len = bgp_packet_withdraw (peer, s, &p, afi, safi, NULL, NULL);

      /* Set total path attribute length. */
      stream_putw_at (s, pos, total_attr_len);
    }

  bgp_packet_set_size (s);

  packet = bgp_packet_dup (s);
  stream_free (s);

  /* Add packet to the peer. */
  bgp_packet_add (peer, packet);

  BGP_WRITE_ON (peer->t_write, bgp_write, peer->fd);
}

/* Get next packet to be written.  */
struct stream *
bgp_write_packet (struct peer *peer)
{
  afi_t afi;
  safi_t safi;
  struct stream *s = NULL;
  struct bgp_advertise *adv;

  s = stream_fifo_head (peer->obuf);
  if (s)
    return s;

  for (afi = AFI_IP; afi < AFI_MAX; afi++)
    for (safi = SAFI_UNICAST; safi < SAFI_MAX; safi++)
      {
	adv = FIFO_HEAD (&peer->sync[afi][safi]->withdraw);
	if (adv)
	  {
	    s = bgp_withdraw_packet (peer, afi, safi);
	    if (s)
	      return s;
	  }
      }
    
  for (afi = AFI_IP; afi < AFI_MAX; afi++)
    for (safi = SAFI_UNICAST; safi < SAFI_MAX; safi++)
      {
	adv = FIFO_HEAD (&peer->sync[afi][safi]->update);
	if (adv)
	  {
            if (adv->binfo && adv->binfo->uptime < peer->synctime[afi][safi])
	      {
		if (CHECK_FLAG (adv->binfo->peer->cap, PEER_CAP_RESTART_RCV)
		    && CHECK_FLAG (adv->binfo->peer->cap, PEER_CAP_RESTART_ADV)
		    && ! CHECK_FLAG (adv->binfo->flags, BGP_INFO_STALE)
		    && safi != SAFI_MPLS_VPN)
		  {
		    if (CHECK_FLAG (adv->binfo->peer->af_sflags[afi][safi],
			PEER_STATUS_EOR_RECEIVED))
		      s = bgp_update_packet (peer, afi, safi);
		  }
		else
		  s = bgp_update_packet (peer, afi, safi);
	      }

	    if (s)
	      return s;
	  }

	if (CHECK_FLAG (peer->cap, PEER_CAP_RESTART_RCV))
	  {
	    if (peer->afc_nego[afi][safi] && peer->synctime[afi][safi]
		&& ! CHECK_FLAG (peer->af_sflags[afi][safi], PEER_STATUS_EOR_SEND)
		&& safi != SAFI_MPLS_VPN)
	      {
		SET_FLAG (peer->af_sflags[afi][safi], PEER_STATUS_EOR_SEND);
		return bgp_update_packet_eor (peer, afi, safi);
	      }
	  }
      }

  return NULL;
}

/* Is there partially written packet or updates we can send right
   now.  */
int
bgp_write_proceed (struct peer *peer)
{
  afi_t afi;
  safi_t safi;
  struct bgp_advertise *adv;

  if (stream_fifo_head (peer->obuf))
    return 1;

  for (afi = AFI_IP; afi < AFI_MAX; afi++)
    for (safi = SAFI_UNICAST; safi < SAFI_MAX; safi++)
      if (FIFO_HEAD (&peer->sync[afi][safi]->withdraw))
	return 1;

  for (afi = AFI_IP; afi < AFI_MAX; afi++)
    for (safi = SAFI_UNICAST; safi < SAFI_MAX; safi++)
      if ((adv = FIFO_HEAD (&peer->sync[afi][safi]->update)) != NULL)
	if (adv->binfo->uptime < peer->synctime[afi][safi])
	  return 1;

  return 0;
}

/* Write packet to the peer. */
int
bgp_write (struct thread *thread)
{
  struct peer *peer;
  u_char type;
  struct stream *s; 
  int num;
  int count = 0;
  int write_errno;

  /* Yes first of all get peer pointer. */
  peer = THREAD_ARG (thread);
  peer->t_write = NULL;

  /* For non-blocking IO check. */
  if (peer->status == Connect)
    {
      bgp_connect_check (peer);
      return 0;
    }

    /* Nonblocking write until TCP output buffer is full.  */
  while (1)
    {
      int writenum;

      s = bgp_write_packet (peer);
      if (! s)
	return 0;

      /* Number of bytes to be sent.  */
      writenum = stream_get_endp (s) - stream_get_getp (s);

      /* Call write() system call.  */
      num = write (peer->fd, STREAM_PNT (s), writenum);
      write_errno = errno;
      if (num <= 0)
	{
	  /* Partial write. */
	  if (write_errno == EWOULDBLOCK || write_errno == EAGAIN)
	      break;

	  bgp_stop (peer);
	  peer->status = Idle;
	  bgp_timer_set (peer);
	  return 0;
	}
      if (num != writenum)
	{
	  stream_forward (s, num);

	  if (write_errno == EAGAIN)
	    break;

	  continue;
	}

      /* Retrieve BGP packet type. */
      stream_set_getp (s, BGP_MARKER_SIZE + 2);
      type = stream_getc (s);

      switch (type)
	{
	case BGP_MSG_OPEN:
	  peer->open_out++;
	  break;
	case BGP_MSG_UPDATE:
	  peer->update_out++;
	  break;
	case BGP_MSG_NOTIFY:
	  peer->notify_out++;

	  /* BGP_EVENT_ADD (peer, BGP_Stop); */
	  bgp_stop_with_error (peer);
	  bgp_fsm_change_status (peer, Idle);
	  bgp_timer_set (peer);
	  return 0;
	  break;
	case BGP_MSG_KEEPALIVE:
	  peer->keepalive_out++;
	  break;
	case BGP_MSG_ROUTE_REFRESH_NEW:
	case BGP_MSG_ROUTE_REFRESH_OLD:
	  peer->refresh_out++;
	  break;
	case BGP_MSG_CAPABILITY:
	  peer->dynamic_cap_out++;
	  break;
	}

      /* OK we send packet so delete it. */
      bgp_packet_delete (peer);

      if (++count >= BGP_WRITE_PACKET_MAX)
	break;
    }
  
  if (bgp_write_proceed (peer))
    BGP_WRITE_ON (peer->t_write, bgp_write, peer->fd);
  
  return 0;
}

/* This is only for sending NOTIFICATION message to neighbor. */
int
bgp_write_notify (struct peer *peer)
{
  int ret;
  u_char type;
  struct stream *s; 

  /* There should be at least one packet. */
  s = stream_fifo_head (peer->obuf);
  if (!s)
    return 0;
  assert (stream_get_endp (s) >= BGP_HEADER_SIZE);

  /* I'm not sure fd is writable. */
  ret = writen (peer->fd, STREAM_DATA (s), stream_get_endp (s));
  if (ret <= 0)
    {
      bgp_stop (peer);
      peer->status = Idle;
      bgp_timer_set (peer);
      return 0;
    }

  /* Retrieve BGP packet type. */
  stream_set_getp (s, BGP_MARKER_SIZE + 2);
  type = stream_getc (s);

  assert (type == BGP_MSG_NOTIFY);

  /* Type should be notify. */
  peer->notify_out++;

  /* We don't call event manager at here for avoiding other events. */
  if (peer->status == Established)
    bgp_stop (peer);
  else
    {
      bgp_stop_with_error (peer);
      bgp_fsm_change_status (peer, Idle);
    }
  bgp_timer_set (peer);

  return 0;
}

/* Make keepalive packet and send it to the peer. */
void
bgp_keepalive_send (struct peer *peer)
{
  struct stream *s;
  int length;

  s = stream_new (BGP_MAX_PACKET_SIZE);

  /* Make keepalive packet. */
  bgp_packet_set_marker (s, BGP_MSG_KEEPALIVE);

  /* Set packet size. */
  length = bgp_packet_set_size (s);

  /* Dump packet if debug option is set. */
  /* bgp_packet_dump (s); */
 
  if (BGP_DEBUG (keepalive, KEEPALIVE))  
    zlog_info ("%s sending KEEPALIVE", peer->host); 
  if (BGP_DEBUG (normal, NORMAL))
    zlog_info ("%s send message type %d, length (incl. header) %d",
               peer->host, BGP_MSG_KEEPALIVE, length);

  /* Add packet to the peer. */
  bgp_packet_add (peer, s);

  BGP_WRITE_ON (peer->t_write, bgp_write, peer->fd);
}

/* Make open packet and send it to the peer. */
void
bgp_open_send (struct peer *peer)
{
  struct stream *s;
  int length;
  u_int16_t send_holdtime;
  as_t local_as;

  if (CHECK_FLAG (peer->config, PEER_CONFIG_TIMER))
    send_holdtime = peer->holdtime;
  else
    send_holdtime = peer->bgp->default_holdtime;

  /* local-as Change */
  if (peer->change_local_as)
    local_as = peer->change_local_as; 
  else
    local_as = peer->local_as; 

  s = stream_new (BGP_MAX_PACKET_SIZE);

  /* Make open packet. */
  bgp_packet_set_marker (s, BGP_MSG_OPEN);

  /* Set open packet values. */
  stream_putc (s, BGP_VERSION_4);        /* BGP version */
  stream_putw (s, local_as);		 /* My Autonomous System*/
  stream_putw (s, send_holdtime);     	 /* Hold Time */
  stream_put_in_addr (s, &peer->local_id); /* BGP Identifier */

  /* Set capability code. */
  bgp_open_capability (s, peer);

  /* Set BGP packet length. */
  length = bgp_packet_set_size (s);

  if (BGP_DEBUG (normal, NORMAL))
    zlog_info ("%s sending OPEN, version %d, my as %d, holdtime %d, id %s", 
	       peer->host, BGP_VERSION_4, local_as,
	       send_holdtime, inet_ntoa (peer->local_id));

  if (BGP_DEBUG (normal, NORMAL))
    zlog_info ("%s send message type %d, length (incl. header) %d",
	       peer->host, BGP_MSG_OPEN, length);

  /* Dump packet if debug option is set. */
  /* bgp_packet_dump (s); */

  /* Add packet to the peer. */
  bgp_packet_add (peer, s);

  BGP_WRITE_ON (peer->t_write, bgp_write, peer->fd);
}

/* Send BGP notify packet with data potion. */
void
bgp_notify_send_with_data (struct peer *peer, u_char code, u_char sub_code,
			   u_char *data, size_t datalen)
{
  struct stream *s;
  int length;

  /* Allocate new stream. */
  s = stream_new (BGP_MAX_PACKET_SIZE);

  /* Make nitify packet. */
  bgp_packet_set_marker (s, BGP_MSG_NOTIFY);

  /* Set notify packet values. */
  stream_putc (s, code);        /* BGP notify code */
  stream_putc (s, sub_code);	/* BGP notify sub_code */

  /* If notify data is present. */
  if (data)
    stream_write (s, data, datalen);
  
  /* Set BGP packet length. */
  length = bgp_packet_set_size (s);
  
  /* Add packet to the peer. */
  stream_fifo_clean (peer->obuf);
  bgp_packet_add (peer, s);

  /* For debug */
  {
    struct bgp_notify bgp_notify;
    int first = 0;
    int i;
    char c[4];

    bgp_notify.code = code;
    bgp_notify.subcode = sub_code;
    bgp_notify.data = NULL;
    bgp_notify.length = length - BGP_MSG_NOTIFY_MIN_SIZE;
    
    if (bgp_notify.length)
      {
	bgp_notify.data = XMALLOC (MTYPE_TMP, bgp_notify.length * 3);
	for (i = 0; i < bgp_notify.length; i++)
	  if (first)
	    {
	      sprintf (c, " %02x", data[i]);
	      strcat (bgp_notify.data, c);
	    }
	  else
	    {
	      first = 1;
	      sprintf (c, "%02x", data[i]);
	      strcpy (bgp_notify.data, c);
	    }
      }
    bgp_notify_print (peer, &bgp_notify, "sending");
    if (bgp_notify.data)
      XFREE (MTYPE_TMP, bgp_notify.data);
  }

  if (BGP_DEBUG (normal, NORMAL))
    zlog_info ("%s send message type %d, length (incl. header) %d",
	       peer->host, BGP_MSG_NOTIFY, length);

  /* peer reset cause */
  if (sub_code != BGP_NOTIFY_CEASE_CONFIG_CHANGE)
    {
      if (sub_code == BGP_NOTIFY_CEASE_ADMIN_RESET)
	peer->last_reset = PEER_DOWN_USER_RESET;
      else if (sub_code == BGP_NOTIFY_CEASE_ADMIN_SHUTDOWN)
	peer->last_reset = PEER_DOWN_USER_SHUTDOWN;
      else if (sub_code == BGP_NOTIFY_CEASE_PEER_UNCONFIG)
	peer->last_reset = PEER_DOWN_NEIGHBOR_DELETE;
      else
	peer->last_reset = PEER_DOWN_NOTIFY_SEND;
    }
  /* Call imidiately. */
  BGP_WRITE_OFF (peer->t_write);

  bgp_write_notify (peer);
}

/* Send BGP notify packet. */
void
bgp_notify_send (struct peer *peer, u_char code, u_char sub_code)
{
  bgp_notify_send_with_data (peer, code, sub_code, NULL, 0);
}

char *
afi2str (afi_t afi)
{
  if (afi == AFI_IP)
    return "AFI_IP";
  else if (afi == AFI_IP6)
    return "AFI_IP6";
  else
    return "Unknown AFI";
}

char *
safi2str (safi_t safi)
{
  if (safi == SAFI_UNICAST)
    return "SAFI_UNICAST";
  else if (safi == SAFI_MULTICAST)
    return "SAFI_MULTICAST";
  else if (safi == SAFI_MPLS_VPN || safi == BGP_SAFI_VPNV4)
    return "SAFI_MPLS_VPN";
  else
    return "Unknown SAFI";
}