Apply by doing:
	cd /usr/src
	patch -p0 < 001_bgpd.patch

And then rebuild and install bgpd:
	cd usr.sbin/bgpd/
	make obj
	make depend
	make 
	make install

Index: usr.sbin/bgpd/session.c
===================================================================
RCS file: /cvs/src/usr.sbin/bgpd/session.c,v
retrieving revision 1.326
diff -u -p -u -r1.326 session.c
--- usr.sbin/bgpd/session.c	1 Dec 2012 10:35:17 -0000	1.326
+++ usr.sbin/bgpd/session.c	16 Mar 2013 03:31:30 -0000
@@ -1034,13 +1034,12 @@ session_accept(int listenfd)
 	len = sizeof(cliaddr);
 	if ((connfd = accept(listenfd,
 	    (struct sockaddr *)&cliaddr, &len)) == -1) {
-		if (errno == ENFILE || errno == EMFILE) {
+		if (errno == ENFILE || errno == EMFILE)
 			pauseaccept = getmonotime();
-			return;
-		} else if (errno == EWOULDBLOCK || errno == EINTR)
-			return;
-		else
+		else if (errno != EWOULDBLOCK && errno != EINTR &&
+		    errno != ECONNABORTED)
 			log_warn("accept");
+		return;
 	}
 
 	p = getpeerbyip((struct sockaddr *)&cliaddr);