bgpd: RFC 4271 DelayOpenTimer

Changes implement the DelayOpenTimer functionality proposed in RFC 4271.

Signed-off-by: David Schweizer <dschweizer@opensourcerouting.org>

1 files changed, 161 insertions, 16 deletions

diff --git a/bgpd/bgp_fsm.c b/bgpd/bgp_fsm.c
index dd31a9b7c..ce665feb4 100644
--- a/bgpd/bgp_fsm.c
+++ b/bgpd/bgp_fsm.c
@@ -67,12 +67,14 @@ static const char *const bgp_event_str[] = {
 	"BGP_Start",
 	"BGP_Stop",
 	"TCP_connection_open",
+	"TCP_connection_open_w_delay",
 	"TCP_connection_closed",
 	"TCP_connection_open_failed",
 	"TCP_fatal_error",
 	"ConnectRetry_timer_expired",
 	"Hold_Timer_expired",
 	"KeepAlive_timer_expired",
+	"DelayOpen_timer_expired",
 	"Receive_OPEN_message",
 	"Receive_KEEPALIVE_message",
 	"Receive_UPDATE_message",
@@ -92,6 +94,7 @@ int bgp_event(struct thread *);
 static int bgp_start_timer(struct thread *);
 static int bgp_connect_timer(struct thread *);
 static int bgp_holdtime_timer(struct thread *);
+static int bgp_delayopen_timer(struct thread *);
 
 /* BGP FSM functions. */
 static int bgp_start(struct peer *);
@@ -174,10 +177,12 @@ static struct peer *peer_xfer_conn(struct peer *from_peer)
 
 	BGP_TIMER_OFF(peer->t_routeadv);
 	BGP_TIMER_OFF(peer->t_connect);
+	BGP_TIMER_OFF(peer->t_delayopen);
 	BGP_TIMER_OFF(peer->t_connect_check_r);
 	BGP_TIMER_OFF(peer->t_connect_check_w);
 	BGP_TIMER_OFF(from_peer->t_routeadv);
 	BGP_TIMER_OFF(from_peer->t_connect);
+	BGP_TIMER_OFF(from_peer->t_delayopen);
 	BGP_TIMER_OFF(from_peer->t_connect_check_r);
 	BGP_TIMER_OFF(from_peer->t_connect_check_w);
 	BGP_TIMER_OFF(from_peer->t_process_packet);
@@ -233,6 +238,7 @@ static struct peer *peer_xfer_conn(struct peer *from_peer)
 	peer->v_holdtime = from_peer->v_holdtime;
 	peer->v_keepalive = from_peer->v_keepalive;
 	peer->v_routeadv = from_peer->v_routeadv;
+	peer->v_delayopen = from_peer->v_delayopen;
 	peer->v_gr_restart = from_peer->v_gr_restart;
 	peer->cap = from_peer->cap;
 	status = peer->status;
@@ -364,6 +370,7 @@ void bgp_timer_set(struct peer *peer)
 		BGP_TIMER_OFF(peer->t_holdtime);
 		bgp_keepalives_off(peer);
 		BGP_TIMER_OFF(peer->t_routeadv);
+		BGP_TIMER_OFF(peer->t_delayopen);
 		break;
 
 	case Connect:
@@ -371,8 +378,13 @@ void bgp_timer_set(struct peer *peer)
 		   status.  Make sure start timer is off and connect timer is
 		   on. */
 		BGP_TIMER_OFF(peer->t_start);
-		BGP_TIMER_ON(peer->t_connect, bgp_connect_timer,
-			     peer->v_connect);
+		if (CHECK_FLAG(peer->flags, PEER_FLAG_TIMER_DELAYOPEN))
+			BGP_TIMER_ON(peer->t_connect, bgp_connect_timer,
+				     (peer->v_delayopen + peer->v_connect));
+		else
+			BGP_TIMER_ON(peer->t_connect, bgp_connect_timer,
+				     peer->v_connect);
+
 		BGP_TIMER_OFF(peer->t_holdtime);
 		bgp_keepalives_off(peer);
 		BGP_TIMER_OFF(peer->t_routeadv);
@@ -387,8 +399,13 @@ void bgp_timer_set(struct peer *peer)
 		    || CHECK_FLAG(peer->sflags, PEER_STATUS_NSF_WAIT)) {
 			BGP_TIMER_OFF(peer->t_connect);
 		} else {
-			BGP_TIMER_ON(peer->t_connect, bgp_connect_timer,
-				     peer->v_connect);
+			if (CHECK_FLAG(peer->flags, PEER_FLAG_TIMER_DELAYOPEN))
+				BGP_TIMER_ON(
+					peer->t_connect, bgp_connect_timer,
+					(peer->v_delayopen + peer->v_connect));
+			else
+				BGP_TIMER_ON(peer->t_connect, bgp_connect_timer,
+					     peer->v_connect);
 		}
 		BGP_TIMER_OFF(peer->t_holdtime);
 		bgp_keepalives_off(peer);
@@ -407,6 +424,7 @@ void bgp_timer_set(struct peer *peer)
 		}
 		bgp_keepalives_off(peer);
 		BGP_TIMER_OFF(peer->t_routeadv);
+		BGP_TIMER_OFF(peer->t_delayopen);
 		break;
 
 	case OpenConfirm:
@@ -425,6 +443,7 @@ void bgp_timer_set(struct peer *peer)
 			bgp_keepalives_on(peer);
 		}
 		BGP_TIMER_OFF(peer->t_routeadv);
+		BGP_TIMER_OFF(peer->t_delayopen);
 		break;
 
 	case Established:
@@ -432,6 +451,7 @@ void bgp_timer_set(struct peer *peer)
 		   off. */
 		BGP_TIMER_OFF(peer->t_start);
 		BGP_TIMER_OFF(peer->t_connect);
+		BGP_TIMER_OFF(peer->t_delayopen);
 
 		/* Same as OpenConfirm, if holdtime is zero then both holdtime
 		   and keepalive must be turned off. */
@@ -455,6 +475,7 @@ void bgp_timer_set(struct peer *peer)
 		BGP_TIMER_OFF(peer->t_holdtime);
 		bgp_keepalives_off(peer);
 		BGP_TIMER_OFF(peer->t_routeadv);
+		BGP_TIMER_OFF(peer->t_delayopen);
 		break;
 	case BGP_STATUS_MAX:
 		flog_err(EC_LIB_DEVELOPMENT,
@@ -488,6 +509,10 @@ static int bgp_connect_timer(struct thread *thread)
 
 	peer = THREAD_ARG(thread);
 
+	/* stop the DelayOpenTimer if it is running */
+	if (peer->t_delayopen)
+		BGP_TIMER_OFF(peer->t_delayopen);
+
 	assert(!peer->t_write);
 	assert(!peer->t_read);
 
@@ -564,6 +589,23 @@ int bgp_routeadv_timer(struct thread *thread)
 	return 0;
 }
 
+/* RFC 4271 DelayOpenTimer */
+int bgp_delayopen_timer(struct thread *thread)
+{
+	struct peer *peer;
+
+	peer = THREAD_ARG(thread);
+
+	if (bgp_debug_neighbor_events(peer))
+		zlog_debug("%s [FSM] Timer (DelayOpentimer expire)",
+			   peer->host);
+
+	THREAD_VAL(thread) = DelayOpen_timer_expired;
+	bgp_event(thread); /* bgp_event unlocks peer */
+
+	return 0;
+}
+
 /* BGP Peer Down Cause */
 const char *const peer_down_str[] = {"",
 			       "Router ID changed",
@@ -1299,6 +1341,7 @@ int bgp_stop(struct peer *peer)
 	BGP_TIMER_OFF(peer->t_connect);
 	BGP_TIMER_OFF(peer->t_holdtime);
 	BGP_TIMER_OFF(peer->t_routeadv);
+	BGP_TIMER_OFF(peer->t_delayopen);
 
 	/* Clear input and output buffer.  */
 	frr_with_mutex(&peer->io_mtx) {
@@ -1357,6 +1400,12 @@ int bgp_stop(struct peer *peer)
 		peer->v_holdtime = peer->bgp->default_holdtime;
 	}
 
+	/* Reset DelayOpenTime */
+	if (CHECK_FLAG(peer->flags, PEER_FLAG_TIMER_DELAYOPEN))
+		peer->v_delayopen = peer->delayopen;
+	else
+		peer->v_delayopen = peer->bgp->default_delayopen;
+
 	peer->update_time = 0;
 
 /* Until we are sure that there is no problem about prefix count
@@ -1469,7 +1518,10 @@ static int bgp_connect_check(struct thread *thread)
 
 	/* When status is 0 then TCP connection is established. */
 	if (status == 0) {
-		BGP_EVENT_ADD(peer, TCP_connection_open);
+		if (CHECK_FLAG(peer->flags, PEER_FLAG_TIMER_DELAYOPEN))
+			BGP_EVENT_ADD(peer, TCP_connection_open_w_delay);
+		else
+			BGP_EVENT_ADD(peer, TCP_connection_open);
 		return 1;
 	} else {
 		if (bgp_debug_neighbor_events(peer))
@@ -1516,11 +1568,63 @@ static int bgp_connect_success(struct peer *peer)
 			zlog_debug("%s passive open", peer->host);
 	}
 
+	/* Send an open message */
 	bgp_open_send(peer);
 
 	return 0;
 }
 
+/* TCP connection open with RFC 4271 optional session attribute DelayOpen flag
+ * set.
+ */
+static int bgp_connect_success_w_delayopen(struct peer *peer)
+{
+	if (peer->fd < 0) {
+		flog_err(EC_BGP_CONNECT, "%s: peer's fd is negative value %d",
+			 __func__, peer->fd);
+		bgp_stop(peer);
+		return -1;
+	}
+
+	if (bgp_getsockname(peer) < 0) {
+		flog_err_sys(EC_LIB_SOCKET,
+			     "%s: bgp_getsockname(): failed for peer %s, fd %d",
+			     __func__, peer->host, peer->fd);
+		bgp_notify_send(peer, BGP_NOTIFY_FSM_ERR,
+				bgp_fsm_error_subcode(peer->status));
+		bgp_writes_on(peer);
+		return -1;
+	}
+
+	bgp_reads_on(peer);
+
+	if (bgp_debug_neighbor_events(peer)) {
+		char buf1[SU_ADDRSTRLEN];
+
+		if (!CHECK_FLAG(peer->sflags, PEER_STATUS_ACCEPT_PEER))
+			zlog_debug("%s open active, local address %s",
+				   peer->host,
+				   sockunion2str(peer->su_local, buf1,
+						 SU_ADDRSTRLEN));
+		else
+			zlog_debug("%s passive open", peer->host);
+	}
+
+	/* set the DelayOpenTime to the inital value */
+	peer->v_delayopen = peer->delayopen;
+
+	/* Start the DelayOpenTimer if it is not already running */
+	if (!peer->t_delayopen)
+		BGP_TIMER_ON(peer->t_delayopen, bgp_delayopen_timer,
+			     peer->v_delayopen);
+
+	if (bgp_debug_neighbor_events(peer))
+		zlog_debug("%s [FSM] BGP OPEN message delayed for %d seconds",
+			   peer->host, peer->delayopen);
+
+	return 0;
+}
+
 /* TCP connect fail */
 static int bgp_connect_fail(struct peer *peer)
 {
@@ -1535,7 +1639,8 @@ static int bgp_connect_fail(struct peer *peer)
 }
 
 /* This function is the first starting point of all BGP connection. It
-   try to connect to remote peer with non-blocking IO. */
+ * try to connect to remote peer with non-blocking IO.
+ */
 int bgp_start(struct peer *peer)
 {
 	int status;
@@ -1633,6 +1738,7 @@ int bgp_start(struct peer *peer)
 			zlog_debug(
 				"%s [FSM] Connect immediately success, fd %d",
 				peer->host, peer->fd);
+
 		BGP_EVENT_ADD(peer, TCP_connection_open);
 		break;
 	case connect_in_progress:
@@ -1682,6 +1788,10 @@ static int bgp_reconnect(struct peer *peer)
 
 static int bgp_fsm_open(struct peer *peer)
 {
+	/* If DelayOpen is active, we may still need to send an open message */
+	if ((peer->status == Connect) || (peer->status == Active))
+		bgp_open_send(peer);
+
 	/* Send keepalive and make keepalive timer */
 	bgp_keepalive_send(peer);
 
@@ -1709,6 +1819,21 @@ static int bgp_fsm_holdtime_expire(struct peer *peer)
 	return bgp_stop_with_notify(peer, BGP_NOTIFY_HOLD_ERR, 0);
 }
 
+/* RFC 4271 DelayOpenTimer_Expires event */
+static int bgp_fsm_delayopen_timer_expire(struct peer *peer)
+{
+	/* Stop the DelayOpenTimer */
+	BGP_TIMER_OFF(peer->t_delayopen);
+
+	/* Send open message to peer */
+	bgp_open_send(peer);
+
+	/* Set the HoldTimer to a large value (4 minutes) */
+	peer->v_holdtime = 245;
+
+	return 0;
+}
+
 /* Start the selection deferral timer thread for the specified AFI, SAFI */
 static int bgp_start_deferral_timer(struct bgp *bgp, afi_t afi, safi_t safi,
 				    struct graceful_restart_info *gr_info)
@@ -2089,12 +2214,14 @@ static const struct {
 		{bgp_start, Connect}, /* BGP_Start                    */
 		{bgp_stop, Idle},     /* BGP_Stop                     */
 		{bgp_stop, Idle},     /* TCP_connection_open          */
+		{bgp_stop, Idle},     /* TCP_connection_open_w_delay */
 		{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},   /* DelayOpen_timer_expired */
 		{bgp_ignore, Idle},   /* Receive_OPEN_message         */
 		{bgp_ignore, Idle},   /* Receive_KEEPALIVE_message    */
 		{bgp_ignore, Idle},   /* Receive_UPDATE_message       */
@@ -2106,46 +2233,56 @@ static const struct {
 		{bgp_ignore, Connect}, /* BGP_Start                    */
 		{bgp_stop, Idle},      /* BGP_Stop                     */
 		{bgp_connect_success, OpenSent}, /* TCP_connection_open */
+		{bgp_connect_success_w_delayopen,
+		 Connect},		    /* TCP_connection_open_w_delay */
 		{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_fsm_exeption, Idle},   /* Hold_Timer_expired           */
 		{bgp_fsm_exeption, Idle},   /* KeepAlive_timer_expired      */
-		{bgp_fsm_exeption, Idle},   /* Receive_OPEN_message         */
-		{bgp_fsm_exeption, Idle},   /* Receive_KEEPALIVE_message    */
-		{bgp_fsm_exeption, Idle},   /* Receive_UPDATE_message       */
-		{bgp_stop, Idle},	   /* Receive_NOTIFICATION_message */
-		{bgp_fsm_exeption, Idle},   /* Clearing_Completed           */
+		{bgp_fsm_delayopen_timer_expire,
+		 OpenSent},		     /* DelayOpen_timer_expired */
+		{bgp_fsm_open, OpenConfirm}, /* Receive_OPEN_message         */
+		{bgp_fsm_exeption, Idle},    /* Receive_KEEPALIVE_message    */
+		{bgp_fsm_exeption, Idle},    /* Receive_UPDATE_message       */
+		{bgp_stop, Idle},	    /* Receive_NOTIFICATION_message */
+		{bgp_fsm_exeption, Idle},    /* Clearing_Completed           */
 	},
 	{
 		/* Active, */
 		{bgp_ignore, Active}, /* BGP_Start                    */
 		{bgp_stop, Idle},     /* BGP_Stop                     */
 		{bgp_connect_success, OpenSent}, /* TCP_connection_open */
+		{bgp_connect_success_w_delayopen,
+		 Active},		  /* TCP_connection_open_w_delay */
 		{bgp_stop, Idle},	 /* TCP_connection_closed        */
 		{bgp_ignore, Active},     /* TCP_connection_open_failed   */
 		{bgp_fsm_exeption, Idle}, /* TCP_fatal_error              */
 		{bgp_start, Connect},     /* ConnectRetry_timer_expired   */
 		{bgp_fsm_exeption, Idle}, /* Hold_Timer_expired           */
 		{bgp_fsm_exeption, Idle}, /* KeepAlive_timer_expired      */
-		{bgp_fsm_exeption, Idle}, /* Receive_OPEN_message         */
-		{bgp_fsm_exeption, Idle}, /* Receive_KEEPALIVE_message    */
-		{bgp_fsm_exeption, Idle}, /* Receive_UPDATE_message       */
-		{bgp_fsm_exeption, Idle}, /* Receive_NOTIFICATION_message */
-		{bgp_fsm_exeption, Idle}, /* Clearing_Completed           */
+		{bgp_fsm_delayopen_timer_expire,
+		 OpenSent},		     /* DelayOpen_timer_expired */
+		{bgp_fsm_open, OpenConfirm}, /* Receive_OPEN_message         */
+		{bgp_fsm_exeption, Idle},    /* Receive_KEEPALIVE_message    */
+		{bgp_fsm_exeption, Idle},    /* Receive_UPDATE_message       */
+		{bgp_fsm_exeption, Idle},    /* Receive_NOTIFICATION_message */
+		{bgp_fsm_exeption, Idle},    /* Clearing_Completed           */
 	},
 	{
 		/* OpenSent, */
 		{bgp_ignore, OpenSent},   /* BGP_Start                    */
 		{bgp_stop, Idle},	 /* BGP_Stop                     */
 		{bgp_stop, Active},       /* TCP_connection_open          */
+		{bgp_fsm_exeption, Idle}, /* TCP_connection_open_w_delay */
 		{bgp_stop, Active},       /* TCP_connection_closed        */
 		{bgp_stop, Active},       /* TCP_connection_open_failed   */
 		{bgp_stop, Active},       /* TCP_fatal_error              */
 		{bgp_fsm_exeption, Idle}, /* ConnectRetry_timer_expired   */
 		{bgp_fsm_holdtime_expire, Idle}, /* Hold_Timer_expired */
 		{bgp_fsm_exeption, Idle},    /* KeepAlive_timer_expired      */
+		{bgp_fsm_exeption, Idle},    /* DelayOpen_timer_expired */
 		{bgp_fsm_open, OpenConfirm}, /* Receive_OPEN_message         */
 		{bgp_fsm_event_error, Idle}, /* Receive_KEEPALIVE_message    */
 		{bgp_fsm_event_error, Idle}, /* Receive_UPDATE_message       */
@@ -2157,12 +2294,14 @@ static const struct {
 		{bgp_ignore, OpenConfirm}, /* BGP_Start                    */
 		{bgp_stop, Idle},	  /* BGP_Stop                     */
 		{bgp_stop, Idle},	  /* TCP_connection_open          */
+		{bgp_fsm_exeption, Idle},  /* TCP_connection_open_w_delay */
 		{bgp_stop, Idle},	  /* TCP_connection_closed        */
 		{bgp_stop, Idle},	  /* TCP_connection_open_failed   */
 		{bgp_stop, Idle},	  /* TCP_fatal_error              */
 		{bgp_fsm_exeption, Idle},  /* ConnectRetry_timer_expired   */
 		{bgp_fsm_holdtime_expire, Idle}, /* Hold_Timer_expired */
 		{bgp_ignore, OpenConfirm},    /* KeepAlive_timer_expired      */
+		{bgp_fsm_exeption, Idle},     /* DelayOpen_timer_expired */
 		{bgp_fsm_exeption, Idle},     /* Receive_OPEN_message         */
 		{bgp_establish, Established}, /* Receive_KEEPALIVE_message    */
 		{bgp_fsm_exeption, Idle},     /* Receive_UPDATE_message       */
@@ -2174,12 +2313,14 @@ static const struct {
 		{bgp_ignore, Established}, /* BGP_Start                    */
 		{bgp_stop, Clearing},      /* BGP_Stop                     */
 		{bgp_stop, Clearing},      /* TCP_connection_open          */
+		{bgp_fsm_exeption, Idle},  /* TCP_connection_open_w_delay */
 		{bgp_stop, Clearing},      /* TCP_connection_closed        */
 		{bgp_stop, Clearing},      /* TCP_connection_open_failed   */
 		{bgp_stop, Clearing},      /* TCP_fatal_error              */
 		{bgp_stop, Clearing},      /* ConnectRetry_timer_expired   */
 		{bgp_fsm_holdtime_expire, Clearing}, /* Hold_Timer_expired */
 		{bgp_ignore, Established}, /* KeepAlive_timer_expired      */
+		{bgp_fsm_exeption, Idle},  /* DelayOpen_timer_expired */
 		{bgp_stop, Clearing},      /* Receive_OPEN_message         */
 		{bgp_fsm_keepalive,
 		 Established}, /* Receive_KEEPALIVE_message    */
@@ -2193,12 +2334,14 @@ static const struct {
 		{bgp_ignore, Clearing}, /* BGP_Start                    */
 		{bgp_stop, Clearing},   /* BGP_Stop                     */
 		{bgp_stop, Clearing},   /* TCP_connection_open          */
+		{bgp_stop, Clearing},   /* TCP_connection_open_w_delay */
 		{bgp_stop, Clearing},   /* TCP_connection_closed        */
 		{bgp_stop, Clearing},   /* TCP_connection_open_failed   */
 		{bgp_stop, Clearing},   /* TCP_fatal_error              */
 		{bgp_stop, Clearing},   /* ConnectRetry_timer_expired   */
 		{bgp_stop, Clearing},   /* Hold_Timer_expired           */
 		{bgp_stop, Clearing},   /* KeepAlive_timer_expired      */
+		{bgp_stop, Clearing},   /* DelayOpen_timer_expired */
 		{bgp_stop, Clearing},   /* Receive_OPEN_message         */
 		{bgp_stop, Clearing},   /* Receive_KEEPALIVE_message    */
 		{bgp_stop, Clearing},   /* Receive_UPDATE_message       */
@@ -2210,12 +2353,14 @@ static const struct {
 		{bgp_ignore, Deleted}, /* BGP_Start                    */
 		{bgp_ignore, Deleted}, /* BGP_Stop                     */
 		{bgp_ignore, Deleted}, /* TCP_connection_open          */
+		{bgp_ignore, Deleted}, /* TCP_connection_open_w_delay */
 		{bgp_ignore, Deleted}, /* TCP_connection_closed        */
 		{bgp_ignore, Deleted}, /* TCP_connection_open_failed   */
 		{bgp_ignore, Deleted}, /* TCP_fatal_error              */
 		{bgp_ignore, Deleted}, /* ConnectRetry_timer_expired   */
 		{bgp_ignore, Deleted}, /* Hold_Timer_expired           */
 		{bgp_ignore, Deleted}, /* KeepAlive_timer_expired      */
+		{bgp_ignore, Deleted}, /* DelayOpen_timer_expired */
 		{bgp_ignore, Deleted}, /* Receive_OPEN_message         */
 		{bgp_ignore, Deleted}, /* Receive_KEEPALIVE_message    */
 		{bgp_ignore, Deleted}, /* Receive_UPDATE_message       */