The rde does not send any IMSG_SESSION_DOWN messages. Remove code in the
SE.

-- 
:wq Claudio

Index: session.c
===================================================================
RCS file: /cvs/src/usr.sbin/bgpd/session.c,v
diff -u -p -r1.461 session.c
--- session.c	18 Jan 2024 14:56:44 -0000	1.461
+++ session.c	23 Jan 2024 14:27:28 -0000
@@ -3344,15 +3344,6 @@ session_dispatch_imsg(struct imsgbuf *im
 					    "IMSG_SESSION_RESTARTED");
 			}
 			break;
-		case IMSG_SESSION_DOWN:
-			if (idx != PFD_PIPE_ROUTE)
-				fatalx("session down not from RDE");
-			if ((p = getpeerbyid(conf, peerid)) == NULL) {
-				log_warnx("no such peer: id=%u", peerid);
-				break;
-			}
-			session_stop(p, ERR_CEASE_ADMIN_DOWN);
-			break;
 		default:
 			break;
 		}