BGP: Long-lived graceful restart enhancements

When use of LLGR is negotiated, handle hold timeout by LLGR instead of by
hard restart. Allow to configure whether BFD session down event should be
handled by GR/LLGR or by hard restart.

1 files changed, 23 insertions, 1 deletions

diff --git a/proto/bgp/bgp.c b/proto/bgp/bgp.c
index 0932051a..369d78f5 100644
--- a/proto/bgp/bgp.c
+++ b/proto/bgp/bgp.c
@@ -704,6 +704,12 @@ bgp_hold_timeout(timer *t)
 
   if (sk_rx_ready(conn->sk) > 0)
     bgp_start_timer(conn->hold_timer, 10);
+  else if ((conn->state == BS_ESTABLISHED) && p->gr_ready && conn->peer_llgr_able)
+  {
+    BGP_TRACE(D_EVENTS, "Hold timer expired");
+    bgp_handle_graceful_restart(p);
+    bgp_conn_enter_idle_state(conn);
+  }
   else
     bgp_error(conn, 4, 0, NULL, 0);
 }
@@ -1046,13 +1052,29 @@ bgp_bfd_notify(struct bfd_request *req)
   int ps = p->p.proto_state;
 
   if (req->down && ((ps == PS_START) || (ps == PS_UP)))
+  {
+    BGP_TRACE(D_EVENTS, "BFD session down");
+
+    /* Ignore if already in GR */
+    if (p->gr_active && (p->cf->bfd == BGP_BFD_GRACEFUL))
+      return;
+
+    if (p->conn && (p->conn->state == BS_ESTABLISHED) &&
+	p->gr_ready && (p->cf->bfd == BGP_BFD_GRACEFUL))
+    {
+      /* Trigger graceful restart */
+      bgp_handle_graceful_restart(p);
+      bgp_conn_enter_idle_state(p->conn);
+    }
+    else
     {
-      BGP_TRACE(D_EVENTS, "BFD session down");
+      /* Trigger session down */
       bgp_store_error(p, NULL, BE_MISC, BEM_BFD_DOWN);
       if (ps == PS_UP)
 	bgp_update_startup_delay(p);
       bgp_stop(p, 0, NULL, 0);
     }
+  }
 }
 
 static void