bgp_packet.c

linux 路由软件 可支持RIP OSPF BGP等

  if (peer->status != Established) 
    {
      zlog_err ("%s [FSM] Update packet received under status %s",
		peer->host, LOOKUP (bgp_status_msg, peer->status));
      bgp_notify_send (peer, BGP_NOTIFY_FSM_ERR, 0);
      return -1;
    }

  /* Set initial values. */
  memset (&attr, 0, sizeof (struct attr));
  memset (&update, 0, sizeof (struct bgp_nlri));
  memset (&withdraw, 0, sizeof (struct bgp_nlri));
  memset (&mp_update, 0, sizeof (struct bgp_nlri));
  memset (&mp_withdraw, 0, sizeof (struct bgp_nlri));

  s = peer->ibuf;
  end = stream_pnt (s) + size;

  /* RFC1771 6.3 If the Unfeasible Routes Length or Total Attribute
     Length is too large (i.e., if Unfeasible Routes Length + Total
     Attribute Length + 23 exceeds the message Length), then the Error
     Subcode is set to Malformed Attribute List.  */
  if (stream_pnt (s) + 2 > end)
    {
      zlog_err ("%s [Error] Update packet error"
		" (packet length is short for unfeasible length)",
		peer->host);
      bgp_notify_send (peer, BGP_NOTIFY_UPDATE_ERR, 
		       BGP_NOTIFY_UPDATE_MAL_ATTR);
      return -1;
    }

  /* Unfeasible Route Length. */
  withdraw_len = stream_getw (s);

  /* Unfeasible Route Length check. */
  if (stream_pnt (s) + withdraw_len > end)
    {
      zlog_err ("%s [Error] Update packet error"
		" (packet unfeasible length overflow %d)",
		peer->host, withdraw_len);
      bgp_notify_send (peer, BGP_NOTIFY_UPDATE_ERR, 
		       BGP_NOTIFY_UPDATE_MAL_ATTR);
      return -1;
    }

  /* Unfeasible Route packet format check. */
  if (withdraw_len > 0)
    {
      ret = bgp_nlri_sanity_check (peer, AFI_IP, stream_pnt (s), withdraw_len);
      if (ret < 0)
	return -1;

      if (BGP_DEBUG (packet, PACKET_RECV))
	  zlog_info ("%s [Update:RECV] Unfeasible NLRI received", peer->host);

      withdraw.afi = AFI_IP;
      withdraw.safi = SAFI_UNICAST;
      withdraw.nlri = stream_pnt (s);
      withdraw.length = withdraw_len;
      stream_forward (s, withdraw_len);
    }
  
  /* Attribute total length check. */
  if (stream_pnt (s) + 2 > end)
    {
      zlog_warn ("%s [Error] Packet Error"
		 " (update packet is short for attribute length)",
		 peer->host);
      bgp_notify_send (peer, BGP_NOTIFY_UPDATE_ERR, 
		       BGP_NOTIFY_UPDATE_MAL_ATTR);
      return -1;
    }

  /* Fetch attribute total length. */
  attribute_len = stream_getw (s);

  /* Attribute length check. */
  if (stream_pnt (s) + attribute_len > end)
    {
      zlog_warn ("%s [Error] Packet Error"
		 " (update packet attribute length overflow %d)",
		 peer->host, attribute_len);
      bgp_notify_send (peer, BGP_NOTIFY_UPDATE_ERR, 
		       BGP_NOTIFY_UPDATE_MAL_ATTR);
      return -1;
    }

  /* Parse attribute when it exists. */
  if (attribute_len)
    {
      ret = bgp_attr_parse (peer, &attr, attribute_len, 
			    &mp_update, &mp_withdraw);
      if (ret < 0)
	return -1;
    }

  /* Logging the attribute. */
  if (BGP_DEBUG (update, UPDATE_IN))
    {
      ret= bgp_dump_attr (peer, &attr, attrstr, BUFSIZ);

      if (ret)
	zlog (peer->log, LOG_INFO, "%s rcvd UPDATE w/ attr: %s",
	      peer->host, attrstr);
    }

  /* Network Layer Reachability Information. */
  update_len = end - stream_pnt (s);

  if (update_len)
    {
      /* Check NLRI packet format and prefix length. */
      ret = bgp_nlri_sanity_check (peer, AFI_IP, stream_pnt (s), update_len);
      if (ret < 0)
	return -1;

      /* Set NLRI portion to structure. */
      update.afi = AFI_IP;
      update.safi = SAFI_UNICAST;
      update.nlri = stream_pnt (s);
      update.length = update_len;
      stream_forward (s, update_len);
    }

  /* NLRI is processed only when the peer is configured specific
     Address Family and Subsequent Address Family. */
  if (peer->afc[AFI_IP][SAFI_UNICAST])
    {
      if (withdraw.length)
	bgp_nlri_parse (peer, NULL, &withdraw);

      if (update.length)
	{
	  /* We check well-known attribute only for IPv4 unicast
	     update. */
	  ret = bgp_attr_check (peer, &attr);
	  if (ret < 0)
	    return -1;

	  bgp_nlri_parse (peer, &attr, &update);
	}

      if (mp_update.length
	  && mp_update.afi == AFI_IP 
	  && mp_update.safi == SAFI_UNICAST)
	bgp_nlri_parse (peer, &attr, &mp_update);

      if (mp_withdraw.length
	  && mp_withdraw.afi == AFI_IP 
	  && mp_withdraw.safi == SAFI_UNICAST)
	bgp_nlri_parse (peer, NULL, &mp_withdraw);

      if (! attribute_len && ! withdraw_len)
	{
	  /* End-of-RIB received */
	  SET_FLAG (peer->af_sflags[AFI_IP][SAFI_UNICAST], PEER_STATUS_EOR_RECEIVED);

	  if (BGP_DEBUG (normal, NORMAL))
	    zlog (peer->log, LOG_INFO, "rcvd End-of-RIB for IPv4 Unicast from %s",
		  peer->host);

	  /* NSF delete stale route */
	  if (peer->nsf[AFI_IP][SAFI_UNICAST])
	    bgp_clear_stale_route (peer, AFI_IP, SAFI_UNICAST);
	}
    }
  if (peer->afc[AFI_IP][SAFI_MULTICAST])
    {
      if (mp_update.length
	  && mp_update.afi == AFI_IP 
	  && mp_update.safi == SAFI_MULTICAST)
	bgp_nlri_parse (peer, &attr, &mp_update);

      if (mp_withdraw.length
	  && mp_withdraw.afi == AFI_IP 
	  && mp_withdraw.safi == SAFI_MULTICAST)
	bgp_nlri_parse (peer, NULL, &mp_withdraw);

      if (! withdraw_len
	  && mp_withdraw.afi == AFI_IP
	  && mp_withdraw.safi == SAFI_MULTICAST
	  && mp_withdraw.length == 0)
	{
	  /* End-of-RIB received */
	  SET_FLAG (peer->af_sflags[AFI_IP][SAFI_MULTICAST], PEER_STATUS_EOR_RECEIVED);

	  if (BGP_DEBUG (normal, NORMAL))
	    zlog (peer->log, LOG_INFO, "rcvd End-of-RIB for IPv4 Multicast from %s",
		  peer->host);

	  /* NSF delete stale route */
	  if (peer->nsf[AFI_IP][SAFI_MULTICAST])
	    bgp_clear_stale_route (peer, AFI_IP, SAFI_MULTICAST);
	}
    }
  if (peer->afc[AFI_IP6][SAFI_UNICAST])
    {
      if (mp_update.length 
	  && mp_update.afi == AFI_IP6 
	  && mp_update.safi == SAFI_UNICAST)
	bgp_nlri_parse (peer, &attr, &mp_update);

      if (mp_withdraw.length 
	  && mp_withdraw.afi == AFI_IP6 
	  && mp_withdraw.safi == SAFI_UNICAST)
	bgp_nlri_parse (peer, NULL, &mp_withdraw);

      if (! withdraw_len
	  && mp_withdraw.afi == AFI_IP6
	  && mp_withdraw.safi == SAFI_UNICAST
	  && mp_withdraw.length == 0)
	{
	  /* End-of-RIB received */
	  SET_FLAG (peer->af_sflags[AFI_IP6][SAFI_UNICAST], PEER_STATUS_EOR_RECEIVED);

	  if (BGP_DEBUG (normal, NORMAL))
	    zlog (peer->log, LOG_INFO, "rcvd End-of-RIB for IPv6 Unicast from %s",
		  peer->host);

	  /* NSF delete stale route */
	  if (peer->nsf[AFI_IP6][SAFI_UNICAST])
	    bgp_clear_stale_route (peer, AFI_IP6, SAFI_UNICAST);
	}
    }
  if (peer->afc[AFI_IP6][SAFI_MULTICAST])
    {
      if (mp_update.length 
	  && mp_update.afi == AFI_IP6 
	  && mp_update.safi == SAFI_MULTICAST)
	bgp_nlri_parse (peer, &attr, &mp_update);

      if (mp_withdraw.length 
	  && mp_withdraw.afi == AFI_IP6 
	  && mp_withdraw.safi == SAFI_MULTICAST)
	bgp_nlri_parse (peer, NULL, &mp_withdraw);

      if (! withdraw_len
	  && mp_withdraw.afi == AFI_IP6
	  && mp_withdraw.safi == SAFI_MULTICAST
	  && mp_withdraw.length == 0)
	{
	  /* End-of-RIB received */
	  SET_FLAG (peer->af_sflags[AFI_IP6][SAFI_MULTICAST], PEER_STATUS_EOR_RECEIVED);

	  if (BGP_DEBUG (update, UPDATE_IN))
	    zlog (peer->log, LOG_INFO, "rcvd End-of-RIB for IPv6 Multicast from %s",
		  peer->host);

	  /* NSF delete stale route */
	  if (peer->nsf[AFI_IP6][SAFI_MULTICAST])
	    bgp_clear_stale_route (peer, AFI_IP6, SAFI_MULTICAST);
	}
    }
  if (peer->afc[AFI_IP][SAFI_MPLS_VPN])
    {
      if (mp_update.length 
	  && mp_update.afi == AFI_IP 
	  && mp_update.safi == BGP_SAFI_VPNV4)
	bgp_nlri_parse_vpnv4 (peer, &attr, &mp_update);

      if (mp_withdraw.length 
	  && mp_withdraw.afi == AFI_IP 
	  && mp_withdraw.safi == BGP_SAFI_VPNV4)
	bgp_nlri_parse_vpnv4 (peer, NULL, &mp_withdraw);

      if (! withdraw_len
	  && mp_withdraw.afi == AFI_IP
	  && mp_withdraw.safi == BGP_SAFI_VPNV4
	  && mp_withdraw.length == 0)
	{
	  /* End-of-RIB received */

	  if (BGP_DEBUG (update, UPDATE_IN))
	    zlog (peer->log, LOG_INFO, "rcvd End-of-RIB for VPNv4 Unicast from %s",
		  peer->host);
	}
    }

  /* Everything is done.  We unintern temporary structures which
     interned in bgp_attr_parse(). */
  if (attr.aspath)
    aspath_unintern (attr.aspath);
  if (attr.community)
    community_unintern (attr.community);
  if (attr.ecommunity)
    ecommunity_unintern (attr.ecommunity);
  if (attr.cluster)
    cluster_unintern (attr.cluster);
  if (attr.transit)
    transit_unintern (attr.transit);

  /* If peering is stopped due to some reason, do not generate BGP
     event.  */
  if (peer->status != Established)
    return 0;

  /* Increment packet counter. */
  peer->update_in++;
  peer->update_time = time (NULL);

  /* Generate BGP event. */
  BGP_EVENT_ADD (peer, Receive_UPDATE_message);

  return 0;
}

/* Notify message treatment function. */
void
bgp_notify_receive (struct peer *peer, bgp_size_t size)
{
  struct bgp_notify bgp_notify;

  if (peer->notify.data)
    {
      XFREE (MTYPE_TMP, peer->notify.data);
      peer->notify.data = NULL;
      peer->notify.length = 0;
    }

  bgp_notify.code = stream_getc (peer->ibuf);
  bgp_notify.subcode = stream_getc (peer->ibuf);
  bgp_notify.length = size - 2;
  bgp_notify.data = NULL;

  /* Preserv notify code and sub code. */
  peer->notify.code = bgp_notify.code;
  peer->notify.subcode = bgp_notify.subcode;
  /* For further diagnostic record returned Data. */
  if (bgp_notify.length)
    {
      peer->notify.length = size - 2;
      peer->notify.data = XMALLOC (MTYPE_TMP, size - 2);
      memcpy (peer->notify.data, stream_pnt (peer->ibuf), size - 2);
    }

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

    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", stream_getc (peer->ibuf));
	      strcat (bgp_notify.data, c);
	    }
	  else
	    {
	      first = 1;
	      sprintf (c, "%02x", stream_getc (peer->ibuf));
	      strcpy (bgp_notify.data, c);
	    }
      }

    bgp_notify_print(peer, &bgp_notify, "received");
    if (bgp_notify.data)
      XFREE (MTYPE_TMP, bgp_notify.data);
  }

  /* peer count update */
  peer->notify_in++;

  if (peer->status == Established)
    peer->last_reset = PEER_DOWN_NOTIFY_RECEIVED;
  /* We have to check for Notify with Unsupported Optional Parameter.
     in that case we fallback to open without the capability option.
     But this done in bgp_stop. We just mark it here to avoid changing
     the fsm tables.  */
  if (bgp_notify.code == BGP_NOTIFY_OPEN_ERR &&
      bgp_notify.subcode == BGP_NOTIFY_OPEN_UNSUP_PARAM )
    UNSET_FLAG (peer->sflags, PEER_STATUS_CAPABILITY_OPEN);

  /* Also apply to Unsupported Capability until remote router support
     capability. */
  if (bgp_notify.code == BGP_NOTIFY_OPEN_ERR &&
      bgp_notify.subcode == BGP_NOTIFY_OPEN_UNSUP_CAPBL)
    UNSET_FLAG (peer->sflags, PEER_STATUS_CAPABILITY_OPEN);

  BGP_EVENT_ADD (peer, Receive_NOTIFICATION_message);
}

/* Keepalive treatment function -- get keepalive send keepalive */
void
bgp_keepalive_receive (struct peer *peer, bgp_size_t size)
{
  if (BGP_DEBUG (keepalive, KEEPALIVE))  
    zlog_info ("%s KEEPALIVE rcvd", peer->host); 
  
  BGP_EVENT_ADD (peer, Receive_KEEPALIVE_message);
}

/* Route refresh message is received. */
void
bgp_route_refresh_receive (struct peer *peer, bgp_size_t size)
{
  afi_t afi;
  safi_t safi;
  u_char reserved;
  struct stream *s;

  /* If peer does not have the capability, send notification. */
  if (! CHECK_FLAG (peer->cap, PEER_CAP_REFRESH_ADV))
    {
      plog_err (peer->log, "%s [Error] BGP route refresh is not enabled",
		peer->host);
      bgp_notify_send (peer,
		       BGP_NOTIFY_HEADER_ERR,
		       BGP_NOTIFY_HEADER_BAD_MESTYPE);
      return;
    }

  /* Status must be Established. */
  if (peer->status != Established) 
    {
      plog_err (peer->log,
		"%s [Error] Route refresh packet received under status %s",
		peer->host, LOOKUP (bgp_status_msg, peer->status));
      bgp_notify_send (peer, BGP_NOTIFY_FSM_ERR, 0);
      return;
    }

  s = peer->ibuf;
  
  /* Parse packet. */
  afi = stream_getw (s);
  reserved = stream_getc (s);
  safi = stream_getc (s);

  if (BGP_DEBUG (normal, NORMAL))
    zlog_info ("%s rcvd REFRESH_REQ for afi/safi: %d/%d",
	       peer->host, afi, safi);

  /* Check AFI and SAFI. */
  if ((afi != AFI_IP && afi != AFI_IP6)
      || (safi != SAFI_UNICAST && safi != SAFI_MULTICAST
	  && safi != BGP_SAFI_VPNV4))
    {
      if (BGP_DEBUG (normal, NORMAL))
	{
	  zlog_info ("%s REFRESH_REQ for unrecognized afi/safi: %d/%d - ignored",
		     peer->host, afi, safi);
	}
      return;
    }

  /* Adjust safi code. */
  if (safi == BGP_SAFI_VPNV4)
    safi = SAFI_MPLS_VPN;

  if (size != BGP_MSG_ROUTE_REFRESH_MIN_SIZE - BGP_HEADER_SIZE)
    {
      u_char *end;
      u_char when_to_refresh;
      u_char orf_type;
      u_int16_t orf_len;

      if (size - (BGP_MSG_ROUTE_REFRESH_MIN_SIZE - BGP_HEADER_SIZE) < 5)
        {
          zlog_info ("%s ORF route refresh length error", peer->host);
          bgp_notify_send (peer, BGP_NOTIFY_CEASE, 0);
          return;
        }

      when_to_refresh = stream_getc (s);
      end = stream_pnt (s) + (size - 5);

      while (stream_pnt (s) < end)
	{
	  orf_type = stream_getc (s); 
	  orf_len = stream_getw (s);

	  if (orf_type == ORF_TYPE_PREFIX
	      || orf_type == ORF_TYPE_PREFIX_OLD)
	    {