bgp_fsm.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

        /* ORF received prefix-filter pnt */
        sprintf (orf_name, "%s.%d.%d", peer->host, afi, safi);
        prefix_bgp_orf_remove_all (orf_name);
      }

  /* Reset keepalive and holdtime */
  if (CHECK_FLAG (peer->config, PEER_CONFIG_TIMER))
    {
      peer->v_keepalive = peer->keepalive;
      peer->v_holdtime = peer->holdtime;
    }
  else
    {
      peer->v_keepalive = peer->bgp->default_keepalive;
      peer->v_holdtime = peer->bgp->default_holdtime;
    }

  peer->update_time = 0;

  /* Until we are sure that there is no problem about prefix count
     this should be commented out.*/
#if 0
  /* Reset prefix count */
  peer->pcount[AFI_IP][SAFI_UNICAST] = 0;
  peer->pcount[AFI_IP][SAFI_MULTICAST] = 0;
  peer->pcount[AFI_IP][SAFI_MPLS_VPN] = 0;
  peer->pcount[AFI_IP6][SAFI_UNICAST] = 0;
  peer->pcount[AFI_IP6][SAFI_MULTICAST] = 0;
#endif /* 0 */

  return 0;
}

/* BGP peer is stoped by the error. */
int
bgp_stop_with_error (struct peer *peer)
{
  /* Double start timer. */
  peer->v_start *= 2;

  /* Overflow check. */
  if (peer->v_start >= (60 * 2))
    peer->v_start = (60 * 2);

  bgp_stop (peer);

  return 0;
}

/* TCP connection open.  Next we send open message to remote peer. And
   add read thread for reading open message. */
int
bgp_connect_success (struct peer *peer)
{
  if (peer->fd < 0)
    {
      zlog_err ("bgp_connect_success peer's fd is negative value %d",
		peer->fd);
      return -1;
    }
  BGP_READ_ON (peer->t_read, bgp_read, peer->fd);

  /* bgp_getsockname (peer); */

  if (! CHECK_FLAG (peer->sflags, PEER_STATUS_ACCEPT_PEER))
    bgp_open_send (peer);

  return 0;
}

/* TCP connect fail */
int
bgp_connect_fail (struct peer *peer)
{
  bgp_stop (peer);
  return 0;
}

/* This function is the first starting point of all BGP connection. It
   try to connect to remote peer with non-blocking IO. */
int
bgp_start (struct peer *peer)
{
  int status;

  /* If the peer is passive mode, force to move to Active mode. */
  if (CHECK_FLAG (peer->flags, PEER_FLAG_PASSIVE))
    {
      BGP_EVENT_ADD (peer, TCP_connection_open_failed);
      return 0;
    }

  status = bgp_connect (peer);

  switch (status)
    {
    case connect_error:
      if (BGP_DEBUG (fsm, FSM))
	plog_info (peer->log, "%s [FSM] Connect error", peer->host);
      BGP_EVENT_ADD (peer, TCP_connection_open_failed);
      break;
    case connect_success:
      if (BGP_DEBUG (fsm, FSM))
	plog_info (peer->log, "%s [FSM] Connect immediately success",
		   peer->host);
      BGP_EVENT_ADD (peer, TCP_connection_open);
      break;
    case connect_in_progress:
      /* To check nonblocking connect, we wait until socket is
         readable or writable. */
      if (BGP_DEBUG (fsm, FSM))
	plog_info (peer->log, "%s [FSM] Non blocking connect waiting result",
		   peer->host);
      if (peer->fd < 0)
	{
	  zlog_err ("bgp_start peer's fd is negative value %d",
		    peer->fd);
	  return -1;
	}
      BGP_READ_ON (peer->t_read, bgp_read, peer->fd);
      BGP_WRITE_ON (peer->t_write, bgp_write, peer->fd);
      break;
    }
  return 0;
}

/* Connect retry timer is expired when the peer status is Connect. */
int
bgp_reconnect (struct peer *peer)
{
  bgp_stop (peer);
  bgp_start (peer);
  return 0;
}

int
bgp_fsm_open (struct peer *peer)
{
  /* Send keepalive and make keepalive timer */
  bgp_keepalive_send (peer);

  /* Reset holdtimer value. */
  BGP_TIMER_OFF (peer->t_holdtime);

  return 0;
}

/* Called after event occured, this function change status and reset
   read/write and timer thread. */
void
bgp_fsm_change_status (struct peer *peer, int status)
{
  bgp_dump_state (peer, peer->status, status);

  /* Preserve old status and change into new status. */
  peer->ostatus = peer->status;
  peer->status = status;
}

/* Keepalive send to peer. */
int
bgp_fsm_keepalive_expire (struct peer *peer)
{
  bgp_keepalive_send (peer);
  return 0;
}

/* Hold timer expire.  This is error of BGP connection. So cut the
   peer and change to Idle status. */
int
bgp_fsm_holdtime_expire (struct peer *peer)
{
  if (BGP_DEBUG (fsm, FSM))
    zlog (peer->log, LOG_DEBUG, "%s [FSM] Hold timer expire", peer->host);

  /* Send notify to remote peer. */
  bgp_notify_send (peer, BGP_NOTIFY_HOLD_ERR, 0);

  /* Sweep if it is temporary peer. */
  if (CHECK_FLAG (peer->sflags, PEER_STATUS_ACCEPT_PEER))
    {
      zlog_info ("%s [Event] Accepting BGP peer is deleted", peer->host);
      peer_delete (peer);
      return -1;
    }

  return 0;
}

/* Status goes to Established.  Send keepalive packet then make first
   update information. */
int
bgp_establish (struct peer *peer)
{
  struct bgp_notify *notify;
  afi_t afi;
  safi_t safi;

  /* Reset capability open status flag. */
  if (! CHECK_FLAG (peer->sflags, PEER_STATUS_CAPABILITY_OPEN))
    SET_FLAG (peer->sflags, PEER_STATUS_CAPABILITY_OPEN);

  /* Clear last notification data. */
  notify = &peer->notify;
  if (notify->data)
    XFREE (MTYPE_TMP, notify->data);
  memset (notify, 0, sizeof (struct bgp_notify));

  /* Clear start timer value to default. */
  peer->v_start = BGP_INIT_START_TIMER;

  /* Increment established count. */
  peer->established++;
  bgp_fsm_change_status (peer, Established);

  /* bgp log-neighbor-changes of neighbor Up */
  if (bgp_flag_check (peer->bgp, BGP_FLAG_LOG_NEIGHBOR_CHANGES))
    zlog_info ("%%ADJCHANGE: neighbor %s Up", peer->host);

#ifdef HAVE_SNMP
  bgpTrapEstablished (peer);
#endif /* HAVE_SNMP */

  /* Reset uptime, send keepalive, send current table. */
  bgp_uptime_reset (peer);

  /* Send route-refresh when ORF is enabled */
  for (afi = AFI_IP ; afi < AFI_MAX ; afi++)
    for (safi = SAFI_UNICAST ; safi < SAFI_MAX ; safi++)
      if (CHECK_FLAG (peer->af_cap[afi][safi], PEER_CAP_ORF_PREFIX_SM_ADV))
	{
	  if (CHECK_FLAG (peer->af_cap[afi][safi], PEER_CAP_ORF_PREFIX_RM_RCV))
	    bgp_route_refresh_send (peer, afi, safi, ORF_TYPE_PREFIX,
				    REFRESH_IMMEDIATE, 0);
	  else if (CHECK_FLAG (peer->af_cap[afi][safi], PEER_CAP_ORF_PREFIX_RM_OLD_RCV))
	    bgp_route_refresh_send (peer, afi, safi, ORF_TYPE_PREFIX_OLD,
				    REFRESH_IMMEDIATE, 0);
	}

  if (peer->v_keepalive)
    bgp_keepalive_send (peer);

  /* First update is deferred until ORF or ROUTE-REFRESH is received */
  for (afi = AFI_IP ; afi < AFI_MAX ; afi++)
    for (safi = SAFI_UNICAST ; safi < SAFI_MAX ; safi++)
      if (CHECK_FLAG (peer->af_cap[afi][safi], PEER_CAP_ORF_PREFIX_RM_ADV))
	if (CHECK_FLAG (peer->af_cap[afi][safi], PEER_CAP_ORF_PREFIX_SM_RCV)
	    || CHECK_FLAG (peer->af_cap[afi][safi], PEER_CAP_ORF_PREFIX_SM_OLD_RCV))
	  SET_FLAG (peer->af_sflags[afi][safi], PEER_STATUS_ORF_WAIT_REFRESH);

  bgp_announce_route_all (peer);

  BGP_TIMER_ON (peer->t_routeadv, bgp_routeadv_timer, 1);

  return 0;
}

/* Keepalive packet is received. */
int
bgp_fsm_keepalive (struct peer *peer)
{
  /* peer count update */
  peer->keepalive_in++;

  BGP_TIMER_OFF (peer->t_holdtime);
  return 0;
}

/* Update packet is received. */
int
bgp_fsm_update (struct peer *peer)
{
  BGP_TIMER_OFF (peer->t_holdtime);
  return 0;
}

/* This is empty event. */
int
bgp_ignore (struct peer *peer)
{
  if (BGP_DEBUG (fsm, FSM))
    zlog (peer->log, LOG_DEBUG, "%s [FSM] bgp_ignore called", peer->host);
  return 0;
}

/* Finite State Machine structure */
struct {
  int (*func) ();
  int next_state;
} FSM [BGP_STATUS_MAX - 1][BGP_EVENTS_MAX - 1] = 
{
  {
    /* Idle state: In Idle state, all events other than BGP_Start is
       ignored.  With BGP_Start event, finite state machine calls
       bgp_start(). */
    {bgp_start,  Connect},	/* BGP_Start                    */
    {bgp_stop,   Idle},		/* BGP_Stop                     */
    {bgp_stop,   Idle},		/* TCP_connection_open          */
    {bgp_stop,   Idle},		/* TCP_connection_closed        */
    {bgp_ignore, Idle},		/* TCP_connection_open_failed   */
    {bgp_stop,   Idle},		/* TCP_fatal_error              */
    {bgp_ignore, Idle},		/* ConnectRetry_timer_expired   */
    {bgp_ignore, Idle},		/* Hold_Timer_expired           */
    {bgp_ignore, Idle},		/* KeepAlive_timer_expired      */
    {bgp_ignore, Idle},		/* Receive_OPEN_message         */
    {bgp_ignore, Idle},		/* Receive_KEEPALIVE_message    */
    {bgp_ignore, Idle},		/* Receive_UPDATE_message       */
    {bgp_ignore, Idle},		/* Receive_NOTIFICATION_message */
  },
  {
    /* Connect */
    {bgp_ignore,  Connect},	/* BGP_Start                    */
    {bgp_stop,    Idle},	/* BGP_Stop                     */
    {bgp_connect_success, OpenSent}, /* TCP_connection_open          */
    {bgp_stop, Idle},		/* TCP_connection_closed        */
    {bgp_connect_fail, Active}, /* TCP_connection_open_failed   */
    {bgp_connect_fail, Idle},	/* TCP_fatal_error              */
    {bgp_reconnect, Connect},	/* ConnectRetry_timer_expired   */
    {bgp_ignore,  Idle},	/* Hold_Timer_expired           */
    {bgp_ignore,  Idle},	/* KeepAlive_timer_expired      */
    {bgp_ignore,  Idle},	/* Receive_OPEN_message         */
    {bgp_ignore,  Idle},	/* Receive_KEEPALIVE_message    */
    {bgp_ignore,  Idle},	/* Receive_UPDATE_message       */
    {bgp_stop,    Idle},	/* Receive_NOTIFICATION_message */
  },
  {
    /* Active, */
    {bgp_ignore,  Active},	/* BGP_Start                    */
    {bgp_stop,    Idle},	/* BGP_Stop                     */
    {bgp_connect_success, OpenSent}, /* TCP_connection_open          */
    {bgp_stop,    Idle},	/* TCP_connection_closed        */
    {bgp_ignore,  Active},	/* TCP_connection_open_failed   */
    {bgp_ignore,  Idle},	/* TCP_fatal_error              */
    {bgp_start,   Connect},	/* ConnectRetry_timer_expired   */
    {bgp_ignore,  Idle},	/* Hold_Timer_expired           */
    {bgp_ignore,  Idle},	/* KeepAlive_timer_expired      */
    {bgp_ignore,  Idle},	/* Receive_OPEN_message         */
    {bgp_ignore,  Idle},	/* Receive_KEEPALIVE_message    */
    {bgp_ignore,  Idle},	/* Receive_UPDATE_message       */
    {bgp_stop_with_error, Idle}, /* Receive_NOTIFICATION_message */
  },
  {
    /* OpenSent, */
    {bgp_ignore,  OpenSent},	/* BGP_Start                    */
    {bgp_stop,    Idle},	/* BGP_Stop                     */
    {bgp_stop,    Idle},	/* TCP_connection_open          */
    {bgp_stop,    Active},	/* TCP_connection_closed        */
    {bgp_ignore,  Idle},	/* TCP_connection_open_failed   */
    {bgp_stop,    Idle},	/* TCP_fatal_error              */
    {bgp_ignore,  Idle},	/* ConnectRetry_timer_expired   */
    {bgp_fsm_holdtime_expire, Idle},	/* Hold_Timer_expired           */
    {bgp_ignore,  Idle},	/* KeepAlive_timer_expired      */
    {bgp_fsm_open,    OpenConfirm},	/* Receive_OPEN_message         */
    {bgp_ignore,  Idle},	/* Receive_KEEPALIVE_message    */
    {bgp_ignore,  Idle},	/* Receive_UPDATE_message       */
    {bgp_stop_with_error, Idle}, /* Receive_NOTIFICATION_message */
  },
  {
    /* OpenConfirm, */
    {bgp_ignore,  OpenConfirm},	/* BGP_Start                    */
    {bgp_stop,    Idle},	/* BGP_Stop                     */
    {bgp_stop,    Idle},	/* TCP_connection_open          */
    {bgp_stop,    Idle},	/* TCP_connection_closed        */
    {bgp_stop,    Idle},	/* TCP_connection_open_failed   */
    {bgp_stop,    Idle},	/* TCP_fatal_error              */
    {bgp_ignore,  Idle},	/* ConnectRetry_timer_expired   */
    {bgp_fsm_holdtime_expire, Idle},	/* Hold_Timer_expired           */
    {bgp_ignore,  OpenConfirm},	/* KeepAlive_timer_expired      */
    {bgp_ignore,  Idle},	/* Receive_OPEN_message         */
    {bgp_establish, Established}, /* Receive_KEEPALIVE_message    */
    {bgp_ignore,  Idle},	/* Receive_UPDATE_message       */
    {bgp_stop_with_error, Idle}, /* Receive_NOTIFICATION_message */
  },
  {
    /* Established, */
    {bgp_ignore,  Established},	/* BGP_Start                    */
    {bgp_stop,    Idle},	/* BGP_Stop                     */
    {bgp_stop,    Idle},	/* TCP_connection_open          */
    {bgp_stop,    Idle},	/* TCP_connection_closed        */
    {bgp_ignore,  Idle},	/* TCP_connection_open_failed   */
    {bgp_stop,    Idle},	/* TCP_fatal_error              */
    {bgp_ignore,  Idle},	/* ConnectRetry_timer_expired   */
    {bgp_fsm_holdtime_expire, Idle}, /* Hold_Timer_expired           */
    {bgp_fsm_keepalive_expire, Established}, /* KeepAlive_timer_expired      */
    {bgp_stop, Idle},		/* Receive_OPEN_message         */
    {bgp_fsm_keepalive, Established}, /* Receive_KEEPALIVE_message    */
    {bgp_fsm_update,   Established}, /* Receive_UPDATE_message       */
    {bgp_stop_with_error, Idle}, /* Receive_NOTIFICATION_message */
  },
};

static char *bgp_event_str[] =
{
  NULL,
  "BGP_Start",
  "BGP_Stop",
  "TCP_connection_open",
  "TCP_connection_closed",
  "TCP_connection_open_failed",
  "TCP_fatal_error",
  "ConnectRetry_timer_expired",
  "Hold_Timer_expired",
  "KeepAlive_timer_expired",
  "Receive_OPEN_message",
  "Receive_KEEPALIVE_message",
  "Receive_UPDATE_message",
  "Receive_NOTIFICATION_message"
};

/* Execute event process. */
int
bgp_event (struct thread *thread)
{
  int ret;
  int event;
  int next;
  struct peer *peer;

  peer = THREAD_ARG (thread);
  event = THREAD_VAL (thread);

  /* Logging this event. */
  next = FSM [peer->status -1][event - 1].next_state;

  if (BGP_DEBUG (fsm, FSM))
    plog_info (peer->log, "%s [FSM] %s (%s->%s)", peer->host, 
	       bgp_event_str[event],
	       LOOKUP (bgp_status_msg, peer->status),
	       LOOKUP (bgp_status_msg, next));
  if (BGP_DEBUG (normal, NORMAL)
      && strcmp (LOOKUP (bgp_status_msg, peer->status), LOOKUP (bgp_status_msg, next)))
    zlog_info ("%s went from %s to %s",
	       peer->host,
	       LOOKUP (bgp_status_msg, peer->status),
	       LOOKUP (bgp_status_msg, next));

  /* Call function. */
  ret = (*(FSM [peer->status - 1][event - 1].func))(peer);

  /* When function do not want proceed next job return -1. */
  if (ret < 0)
    return ret;
    
  /* If status is changed. */
  if (next != peer->status)
    bgp_fsm_change_status (peer, next);

  /* Make sure timer is set. */
  bgp_timer_set (peer);

  return 0;
}