Introduce new route decision tunable "rde med compare (always|strict)".

If set to always the med will also be compared between different AS.
The default is strict which is the way the RFC specifies it.
OK henning@

5 files changed, 43 insertions, 7 deletions

diff --git a/usr.sbin/bgpd/bgpd.conf.5 b/usr.sbin/bgpd/bgpd.conf.5
index 79629645efb..adfa3fe58bb 100644
--- a/usr.sbin/bgpd/bgpd.conf.5
+++ b/usr.sbin/bgpd/bgpd.conf.5
@@ -1,4 +1,4 @@
-.\" $OpenBSD: bgpd.conf.5,v 1.58 2005/07/28 20:32:33 henning Exp $
+.\" $OpenBSD: bgpd.conf.5,v 1.59 2005/08/09 20:27:25 claudio Exp $
 .\"
 .\" Copyright (c) 2004 Claudio Jeker <claudio@openbsd.org>
 .\" Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -242,6 +242,23 @@ section.
 .Pp
 .It Xo
 .Ic rde
+.Ic med
+.Ic compare
+.Pq Ic always Ns \&| Ns Ic strict
+.Xc
+If set to
+.Ic always ,
+the
+.Em MED
+attributes will be comapared always.
+The default is
+.Ic strict
+where the
+.Em MED
+is only compared between peers belonging to the same AS.
+.Pp
+.It Xo
+.Ic rde
 .Ic route-age
 .Pq Ic ignore Ns \&| Ns Ic evaluate
 .Xc
diff --git a/usr.sbin/bgpd/bgpd.h b/usr.sbin/bgpd/bgpd.h
index 5bea6ba98ed..b4d330104d7 100644
--- a/usr.sbin/bgpd/bgpd.h
+++ b/usr.sbin/bgpd/bgpd.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: bgpd.h,v 1.175 2005/07/04 09:37:24 claudio Exp $ */
+/*	$OpenBSD: bgpd.h,v 1.176 2005/08/09 20:27:25 claudio Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -60,6 +60,7 @@
 #define	BGPD_FLAG_DECISION_MASK		0x0f00
 #define	BGPD_FLAG_DECISION_ROUTEAGE	0x0100
 #define	BGPD_FLAG_DECISION_TRANS_AS	0x0200
+#define	BGPD_FLAG_DECISION_MED_ALWAYS	0x0400
 
 #define	BGPD_LOG_UPDATES		0x0001
 
diff --git a/usr.sbin/bgpd/parse.y b/usr.sbin/bgpd/parse.y
index 8fe1c32ed9d..adb8f4a1115 100644
--- a/usr.sbin/bgpd/parse.y
+++ b/usr.sbin/bgpd/parse.y
@@ -1,4 +1,4 @@
-/*	$OpenBSD: parse.y,v 1.170 2005/07/28 20:01:21 henning Exp $ */
+/*	$OpenBSD: parse.y,v 1.171 2005/08/09 20:27:25 claudio Exp $ */
 
 /*
  * Copyright (c) 2002, 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -142,7 +142,7 @@ typedef struct {
 %}
 
 %token	AS ROUTERID HOLDTIME YMIN LISTEN ON FIBUPDATE
-%token	RDE EVALUATE IGNORE
+%token	RDE EVALUATE IGNORE COMPARE
 %token	GROUP NEIGHBOR NETWORK
 %token	REMOTEAS DESCR LOCALADDR MULTIHOP PASSIVE MAXPREFIX ANNOUNCE
 %token	ENFORCE NEIGHBORAS CAPABILITIES REFLECTOR DEPEND
@@ -415,6 +415,19 @@ conf_main	: AS asnumber		{
 			}
 			free($2);
 		}
+		| RDE MED COMPARE STRING	{
+			if (!strcmp($4, "always"))
+				conf->flags |= BGPD_FLAG_DECISION_MED_ALWAYS;
+			else if (!strcmp($4, "strict"))
+				conf->flags &= ~BGPD_FLAG_DECISION_MED_ALWAYS;
+			else {
+				yyerror("rde med compare: "
+				    "unknown setting \"%s\"", $4);
+				free($4);
+				YYERROR;
+			}
+			free($4);
+		}
 		;
 
 mrtdump		: DUMP STRING inout STRING optnumber	{
@@ -1464,6 +1477,7 @@ lookup(char *s)
 		{ "blackhole",		BLACKHOLE},
 		{ "capabilities",	CAPABILITIES},
 		{ "community",		COMMUNITY},
+		{ "compare",		COMPARE},
 		{ "connected",		CONNECTED},
 		{ "deny",		DENY},
 		{ "depend",		DEPEND},
diff --git a/usr.sbin/bgpd/printconf.c b/usr.sbin/bgpd/printconf.c
index aa25203d42e..576991bc8db 100644
--- a/usr.sbin/bgpd/printconf.c
+++ b/usr.sbin/bgpd/printconf.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: printconf.c,v 1.46 2005/07/28 20:14:29 henning Exp $	*/
+/*	$OpenBSD: printconf.c,v 1.47 2005/08/09 20:27:25 claudio Exp $	*/
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -165,6 +165,9 @@ print_mainconf(struct bgpd_config *conf)
 	if (conf->flags & BGPD_FLAG_DECISION_ROUTEAGE)
 		printf("rde route-age evaluate\n");
 
+	if (conf->flags & BGPD_FLAG_DECISION_MED_ALWAYS)
+		printf("rde med compare always\n");
+
 	if (conf->flags & BGPD_FLAG_DECISION_TRANS_AS)
 		printf("transparent-as yes\n");
 
diff --git a/usr.sbin/bgpd/rde_decide.c b/usr.sbin/bgpd/rde_decide.c
index 98117ae4ae0..6ee960e78f1 100644
--- a/usr.sbin/bgpd/rde_decide.c
+++ b/usr.sbin/bgpd/rde_decide.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rde_decide.c,v 1.41 2005/04/12 14:32:01 claudio Exp $ */
+/*	$OpenBSD: rde_decide.c,v 1.42 2005/08/09 20:27:25 claudio Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Claudio Jeker <claudio@openbsd.org>
@@ -137,7 +137,8 @@ prefix_cmp(struct prefix *p1, struct prefix *p2)
 		return (asp2->origin - asp1->origin);
 
 	/* 5. MED decision, only comparable between the same neighboring AS */
-	if (aspath_neighbor(asp1->aspath) == aspath_neighbor(asp2->aspath))
+	if (rde_decisionflags() & BGPD_FLAG_DECISION_MED_ALWAYS ||
+	    aspath_neighbor(asp1->aspath) == aspath_neighbor(asp2->aspath))
 		/* lowest value wins */
 		if ((asp2->med - asp1->med) != 0)
 			return (asp2->med - asp1->med);