From 4967bf6d729d7dd14dff7b672b2fd4afe78a0d86 Mon Sep 17 00:00:00 2001
From: Donatas Abraitis <donatas@opensourcerouting.org>
Date: Thu, 29 Feb 2024 15:37:53 +0200
Subject: [PATCH] bgpd: Send "Send Hold Timer Expired" on such events
 notification

This is required by the current (latest/-02 draft).

IANA has registered code 8 for "Send Hold Timer Expired" in the "BGP
Error (Notification) Codes" sub-registry under the "Border Gateway
Protocol (BGP) Parameters" registry.

https://datatracker.ietf.org/doc/html/draft-ietf-idr-bgp-sendholdtimer

Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>
---
 bgpd/bgp_debug.c  | 2 ++
 bgpd/bgp_fsm.c    | 2 +-
 bgpd/bgp_fsm.h    | 3 +++
 bgpd/bgp_packet.c | 3 ++-
 bgpd/bgpd.h       | 1 +
 5 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/bgpd/bgp_debug.c b/bgpd/bgp_debug.c
index 3ecdc0d3cf..c1b06a0ae3 100644
--- a/bgpd/bgp_debug.c
+++ b/bgpd/bgp_debug.c
@@ -116,6 +116,7 @@ static const struct message bgp_notify_msg[] = {
 	{BGP_NOTIFY_FSM_ERR, "Neighbor Events Error"},
 	{BGP_NOTIFY_CEASE, "Cease"},
 	{BGP_NOTIFY_ROUTE_REFRESH_ERR, "ROUTE-REFRESH Message Error"},
+	{BGP_NOTIFY_SEND_HOLD_ERR, "Send Hold Timer Expired"},
 	{0}};
 
 static const struct message bgp_notify_head_msg[] = {
@@ -515,6 +516,7 @@ const char *bgp_notify_subcode_str(char code, char subcode)
 		return lookup_msg(bgp_notify_update_msg, subcode,
 				  "Unrecognized Error Subcode");
 	case BGP_NOTIFY_HOLD_ERR:
+	case BGP_NOTIFY_SEND_HOLD_ERR:
 		break;
 	case BGP_NOTIFY_FSM_ERR:
 		return lookup_msg(bgp_notify_fsm_msg, subcode,
diff --git a/bgpd/bgp_fsm.c b/bgpd/bgp_fsm.c
index 657c7e22d7..a2d3172882 100644
--- a/bgpd/bgp_fsm.c
+++ b/bgpd/bgp_fsm.c
@@ -1589,7 +1589,7 @@ bgp_stop_with_error(struct peer_connection *connection)
 
 
 /* something went wrong, send notify and tear down */
-static enum bgp_fsm_state_progress
+enum bgp_fsm_state_progress
 bgp_stop_with_notify(struct peer_connection *connection, uint8_t code,
 		     uint8_t sub_code)
 {
diff --git a/bgpd/bgp_fsm.h b/bgpd/bgp_fsm.h
index 2e96ac4c10..bcdd49193f 100644
--- a/bgpd/bgp_fsm.h
+++ b/bgpd/bgp_fsm.h
@@ -122,6 +122,9 @@ extern void bgp_maxmed_update(struct bgp *);
 extern bool bgp_maxmed_onstartup_configured(struct bgp *);
 extern bool bgp_maxmed_onstartup_active(struct bgp *);
 extern int bgp_fsm_error_subcode(int status);
+extern enum bgp_fsm_state_progress
+bgp_stop_with_notify(struct peer_connection *connection, uint8_t code,
+		     uint8_t sub_code);
 
 /**
  * Start the route advertisement timer (that honors MRAI) for all the
diff --git a/bgpd/bgp_packet.c b/bgpd/bgp_packet.c
index da352a8441..55d3efde23 100644
--- a/bgpd/bgp_packet.c
+++ b/bgpd/bgp_packet.c
@@ -148,7 +148,8 @@ static void bgp_packet_add(struct peer_connection *connection,
 				EC_BGP_SENDQ_STUCK_PROPER,
 				"%pBP has not made any SendQ progress for 2 holdtimes (%jds), terminating session",
 				peer, sendholdtime);
-			BGP_EVENT_ADD(connection, TCP_fatal_error);
+			bgp_stop_with_notify(connection,
+					     BGP_NOTIFY_SEND_HOLD_ERR, 0);
 		} else if (delta > (intmax_t)holdtime &&
 			   monotime(NULL) - peer->last_sendq_warn > 5) {
 			flog_warn(
diff --git a/bgpd/bgpd.h b/bgpd/bgpd.h
index cf333e07cc..94bb107253 100644
--- a/bgpd/bgpd.h
+++ b/bgpd/bgpd.h
@@ -1983,6 +1983,7 @@ struct bgp_nlri {
 #define BGP_NOTIFY_FSM_ERR                       5
 #define BGP_NOTIFY_CEASE                         6
 #define BGP_NOTIFY_ROUTE_REFRESH_ERR             7
+#define BGP_NOTIFY_SEND_HOLD_ERR                 8
 
 /* Subcodes for BGP Finite State Machine Error */
 #define BGP_NOTIFY_FSM_ERR_SUBCODE_UNSPECIFIC  0