From f7421e07365e171296702da2023be51730de3d50 Mon Sep 17 00:00:00 2001
From: job <job@openbsd.org>
Date: Wed, 15 May 2024 09:09:38 +0000
Subject: [PATCH] Mark RTR and IPv6 BGP packets with DSCP CS6 (network control)

Additionally, set TCP_NODELAY on the RTR socket, there is no need to
queue up messages towards the RTR server.

OK claudio@
---
 usr.sbin/bgpd/bgpd.c    | 29 ++++++++++++++++++++++++++++-
 usr.sbin/bgpd/session.c |  9 ++++++++-
 2 files changed, 36 insertions(+), 2 deletions(-)

diff --git a/usr.sbin/bgpd/bgpd.c b/usr.sbin/bgpd/bgpd.c
index b4df9efaa8d..5987713052c 100644
--- a/usr.sbin/bgpd/bgpd.c
+++ b/usr.sbin/bgpd/bgpd.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: bgpd.c,v 1.263 2024/04/09 12:05:07 claudio Exp $ */
+/*	$OpenBSD: bgpd.c,v 1.264 2024/05/15 09:09:38 job Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -20,6 +20,8 @@
 #include <sys/socket.h>
 #include <sys/wait.h>
 #include <netinet/in.h>
+#include <netinet/ip.h>
+#include <netinet/tcp.h>
 #include <arpa/inet.h>
 #include <err.h>
 #include <errno.h>
@@ -1342,6 +1344,8 @@ bgpd_rtr_connect(struct rtr_config *r)
 	struct connect_elm *ce;
 	struct sockaddr *sa;
 	socklen_t len;
+	int nodelay = 1;
+	int pre = IPTOS_PREC_INTERNETCONTROL;
 
 	if (connect_cnt >= MAX_CONNECT_CNT) {
 		log_warnx("rtr %s: too many concurrent connection requests",
@@ -1387,6 +1391,29 @@ bgpd_rtr_connect(struct rtr_config *r)
 		return;
 	}
 
+	switch (r->remote_addr.aid) {
+	case AID_INET:
+		if (setsockopt(ce->fd, IPPROTO_IP, IP_TOS, &pre, sizeof(pre)) ==
+		    -1) {
+			log_warn("rtr %s: setsockopt IP_TOS", r->descr);
+			return;
+		}
+		break;
+	case AID_INET6:
+		if (setsockopt(ce->fd, IPPROTO_IPV6, IPV6_TCLASS, &pre,
+		    sizeof(pre)) == -1) {
+			log_warn("rtr %s: setsockopt IP_TOS", r->descr);
+			return;
+		}
+		break;
+	}
+
+	if (setsockopt(ce->fd, IPPROTO_TCP, TCP_NODELAY, &nodelay,
+	    sizeof(nodelay)) == -1) {
+		log_warn("rtr %s: setsockopt TCP_NODELAY", r->descr);
+		return;
+	}
+
 	imsg_compose(ibuf_rtr, IMSG_SOCKET_CONN, ce->id, 0, ce->fd, NULL, 0);
 	free(ce);
 }
diff --git a/usr.sbin/bgpd/session.c b/usr.sbin/bgpd/session.c
index 559e41c1bd2..df990438254 100644
--- a/usr.sbin/bgpd/session.c
+++ b/usr.sbin/bgpd/session.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: session.c,v 1.474 2024/04/24 10:41:34 claudio Exp $ */
+/*	$OpenBSD: session.c,v 1.475 2024/05/15 09:09:38 job Exp $ */
 
 /*
  * Copyright (c) 2003, 2004, 2005 Henning Brauer <henning@openbsd.org>
@@ -1168,6 +1168,13 @@ session_setup_socket(struct peer *p)
 		}
 		break;
 	case AID_INET6:
+		if (setsockopt(p->fd, IPPROTO_IPV6, IPV6_TCLASS, &pre,
+		    sizeof(pre)) == -1) {
+			log_peer_warn(&p->conf, "session_setup_socket "
+			    "setsockopt TCLASS");
+			return (-1);
+		}
+
 		if (p->conf.ebgp) {
 			/*
 			 * set hoplimit to foreign router's distance
-- 
2.20.1