Finally commit the transparent-as and nexthop no-modify stuff I wrote on the

way to FOSDEM. With transparent-as set to ye bgpd will not prepend his own
AS for sent updates. NB the neighbor needs to set "enforce neighbor-as no"
or it will not like the received AS paths. With set nexthop no-modify bgpd
will change the nexthop as done normaly.
OK henning@ man page update with help of jmc@

8 files changed, 88 insertions, 30 deletions

diff --git a/usr.sbin/bgpd/bgpd.conf.5 b/usr.sbin/bgpd/bgpd.conf.5
index 053669f3ce2..16c3dde98ba 100644
--- a/usr.sbin/bgpd/bgpd.conf.5
+++ b/usr.sbin/bgpd/bgpd.conf.5
@@ -1,4 +1,4 @@
-.\" $OpenBSD: bgpd.conf.5,v 1.42 2004/12/31 10:47:37 jaredy Exp $
+.\" $OpenBSD: bgpd.conf.5,v 1.43 2005/03/11 12:54:19 claudio Exp $
 .\"
 .\" Copyright (c) 2004 Claudio Jeker <claudio@openbsd.org>
 .\" Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -254,6 +254,17 @@ router-id 10.0.0.1
 .Pp
 If not given, the BGP ID is determined as the biggest IP address assigned
 to the local machine.
+.Pp
+.It Xo
+.Ic transparent-as
+.Pq Ic yes Ns \&| Ns Ic no
+.Xc
+If set to
+.Ic yes ,
+.Em AS paths
+to EBGP neighbors are not prepended with their own AS.
+The default is
+.Ic no .
 .El
 .Sh NEIGHBORS AND GROUPS
 .Xr bgpd 8
@@ -809,13 +820,18 @@ AS path attribute.
 .Pp
 .It Xo
 .Ic nexthop
-.Po Ar address Ns \&| Ns
-.Ic blackhole Ns \&| Ns Ic reject Pc
+.Sm off
+.Po Ar address \*(Ba
+.Ic blackhole \*(Ba
+.Ic reject \*(Ba
+.Ic no-modify Pc
+.Sm on
 .Xc
 Set the
 .Em NEXTHOP
 AS path attribute
-to a different nexthop address, or use blackhole or reject routes.
+to a different nexthop address, use blackhole or reject routes,
+or do not modify it.
 .Bd -literal -offset indent
 set nexthop 192.168.0.1
 set nexthop blackhole
diff --git a/usr.sbin/bgpd/bgpd.h b/usr.sbin/bgpd/bgpd.h
index 77b623e6d6b..5633c3aa05a 100644
--- a/usr.sbin/bgpd/bgpd.h
+++ b/usr.sbin/bgpd/bgpd.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: bgpd.h,v 1.155 2005/02/01 21:36:01 henning Exp $ */
+/*	$OpenBSD: bgpd.h,v 1.156 2005/03/11 12:54:19 claudio Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -53,6 +53,7 @@
 #define	BGPD_FLAG_REFLECTOR		0x0004
 #define	BGPD_FLAG_DECISION_MASK		0x0f00
 #define	BGPD_FLAG_DECISION_ROUTEAGE	0x0100
+#define	BGPD_FLAG_DECISION_TRANS_AS	0x0200
 
 #define	BGPD_LOG_UPDATES		0x0001
 
@@ -544,6 +545,7 @@ enum action_types {
 	ACTION_SET_NEXTHOP,
 	ACTION_SET_NEXTHOP_REJECT,
 	ACTION_SET_NEXTHOP_BLACKHOLE,
+	ACTION_SET_NEXTHOP_NOMODIFY,
 	ACTION_SET_COMMUNITY,
 /*	ACTION_SCRUB_COMMUNITY, */
 	ACTION_PFTABLE
diff --git a/usr.sbin/bgpd/parse.y b/usr.sbin/bgpd/parse.y
index 9fb235eb863..d75ef81f06d 100644
--- a/usr.sbin/bgpd/parse.y
+++ b/usr.sbin/bgpd/parse.y
@@ -1,4 +1,4 @@
-/*	$OpenBSD: parse.y,v 1.149 2004/12/23 16:09:26 henning Exp $ */
+/*	$OpenBSD: parse.y,v 1.150 2005/03/11 12:54:19 claudio Exp $ */
 
 /*
  * Copyright (c) 2002, 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -145,13 +145,13 @@ typedef struct {
 %token	REMOTEAS DESCR LOCALADDR MULTIHOP PASSIVE MAXPREFIX ANNOUNCE
 %token	ENFORCE NEIGHBORAS CAPABILITIES REFLECTOR DEPEND
 %token	DUMP IN OUT
-%token	LOG ROUTECOLL
+%token	LOG ROUTECOLL TRANSPARENT
 %token	TCP MD5SIG PASSWORD KEY
 %token	ALLOW DENY MATCH
 %token	QUICK
 %token	FROM TO ANY
 %token	PREFIX PREFIXLEN SOURCEAS TRANSITAS COMMUNITY
-%token	SET LOCALPREF MED METRIC NEXTHOP REJECT BLACKHOLE
+%token	SET LOCALPREF MED METRIC NEXTHOP REJECT BLACKHOLE NOMODIFY
 %token	PREPEND_SELF PREPEND_PEER PFTABLE
 %token	ERROR
 %token	IPSEC ESP AH SPI IKE
@@ -307,6 +307,12 @@ conf_main	: AS asnumber		{
 			else
 				conf->flags &= ~BGPD_FLAG_NO_EVALUATE;
 		}
+		| TRANSPARENT yesno	{
+			if ($2 == 1)
+				conf->flags |= BGPD_FLAG_DECISION_TRANS_AS;
+			else
+				conf->flags &= ~BGPD_FLAG_DECISION_TRANS_AS;
+		}
 		| LOG string		{
 			if (!strcmp($2, "updates"))
 				conf->log |= BGPD_LOG_UPDATES;
@@ -1157,6 +1163,11 @@ filter_set_opt	: LOCALPREF number		{
 				fatal(NULL);
 			$$->type = ACTION_SET_NEXTHOP_REJECT;
 		}
+		| NEXTHOP NOMODIFY		{
+			if (($$ = calloc(1, sizeof(struct filter_set))) == NULL)
+				fatal(NULL);
+			$$->type = ACTION_SET_NEXTHOP_NOMODIFY;
+		}
 		| PREPEND_SELF number		{
 			if (($$ = calloc(1, sizeof(struct filter_set))) == NULL)
 				fatal(NULL);
@@ -1323,6 +1334,7 @@ lookup(char *s)
 		{ "neighbor-as",	NEIGHBORAS},
 		{ "network",		NETWORK},
 		{ "nexthop",		NEXTHOP},
+		{ "no-modify",		NOMODIFY},
 		{ "on",			ON},
 		{ "out",		OUT},
 		{ "passive",		PASSIVE},
@@ -1344,7 +1356,8 @@ lookup(char *s)
 		{ "spi",		SPI},
 		{ "tcp",		TCP},
 		{ "to",			TO},
-		{ "transit-as",		TRANSITAS}
+		{ "transit-as",		TRANSITAS},
+		{ "transparent-as",	TRANSPARENT}
 	};
 	const struct keywords	*p;
 
diff --git a/usr.sbin/bgpd/printconf.c b/usr.sbin/bgpd/printconf.c
index 7672002984c..f2901b3b287 100644
--- a/usr.sbin/bgpd/printconf.c
+++ b/usr.sbin/bgpd/printconf.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: printconf.c,v 1.35 2004/11/23 13:07:01 claudio Exp $	*/
+/*	$OpenBSD: printconf.c,v 1.36 2005/03/11 12:54:19 claudio Exp $	*/
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -98,6 +98,9 @@ print_set(struct filter_set_head *set)
 		case ACTION_SET_NEXTHOP_BLACKHOLE:
 			printf("nexthop blackhole ");
 			break;
+		case ACTION_SET_NEXTHOP_NOMODIFY:
+			printf("nexthop no-modify ");
+			break;
 		case ACTION_SET_PREPEND_SELF:
 			printf("prepend-self %u ", s->action.prepend);
 			break;
@@ -141,6 +144,9 @@ 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_TRANS_AS)
+		printf("transparent-as yes\n");
+
 	if (conf->log & BGPD_LOG_UPDATES)
 		printf("log updates\n");
 
diff --git a/usr.sbin/bgpd/rde.h b/usr.sbin/bgpd/rde.h
index 827e8c7966e..c61a6523c7b 100644
--- a/usr.sbin/bgpd/rde.h
+++ b/usr.sbin/bgpd/rde.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rde.h,v 1.62 2004/12/23 15:08:43 henning Exp $ */
+/*	$OpenBSD: rde.h,v 1.63 2005/03/11 12:54:20 claudio Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Claudio Jeker <claudio@openbsd.org> and
@@ -131,18 +131,19 @@ struct path_table {
 
 LIST_HEAD(prefix_head, prefix);
 
-#define	F_ATTR_ORIGIN		0x001
-#define	F_ATTR_ASPATH		0x002
-#define	F_ATTR_NEXTHOP		0x004
-#define	F_ATTR_LOCALPREF	0x008
-#define	F_ATTR_MED		0x010
-#define	F_ATTR_MED_ANNOUNCE	0x020
-#define	F_ATTR_MP_REACH		0x040
-#define	F_ATTR_MP_UNREACH	0x080
-#define	F_PREFIX_ANNOUNCED	0x100
-#define	F_NEXTHOP_REJECT	0x200
-#define	F_NEXTHOP_BLACKHOLE	0x400
-#define	F_ATTR_LINKED		0x800
+#define	F_ATTR_ORIGIN		0x0001
+#define	F_ATTR_ASPATH		0x0002
+#define	F_ATTR_NEXTHOP		0x0004
+#define	F_ATTR_LOCALPREF	0x0008
+#define	F_ATTR_MED		0x0010
+#define	F_ATTR_MED_ANNOUNCE	0x0020
+#define	F_ATTR_MP_REACH		0x0040
+#define	F_ATTR_MP_UNREACH	0x0080
+#define	F_PREFIX_ANNOUNCED	0x0100
+#define	F_NEXTHOP_REJECT	0x0200
+#define	F_NEXTHOP_BLACKHOLE	0x0400
+#define	F_NEXTHOP_NOMODIFY	0x0800
+#define	F_ATTR_LINKED		0x1000
 
 #define ORIGIN_IGP		0
 #define ORIGIN_EGP		1
diff --git a/usr.sbin/bgpd/rde_filter.c b/usr.sbin/bgpd/rde_filter.c
index 819dc6117de..00f17db9798 100644
--- a/usr.sbin/bgpd/rde_filter.c
+++ b/usr.sbin/bgpd/rde_filter.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rde_filter.c,v 1.24 2005/02/24 17:14:53 claudio Exp $ */
+/*	$OpenBSD: rde_filter.c,v 1.25 2005/03/11 12:54:20 claudio Exp $ */
 
 /*
  * Copyright (c) 2004 Claudio Jeker <claudio@openbsd.org>
@@ -85,10 +85,11 @@ rde_apply_set(struct rde_aspath *asp, struct filter_set_head *sh,
 	SIMPLEQ_FOREACH(set, sh, entry) {
 		/*
 		 * default outgoing overrides are only allowed to
-		 * set prepend-self
+		 * set prepend-self and set nexthop no-modify
 		 */
 		if (dir == DIR_DEFAULT_OUT &&
-		    set->type != ACTION_SET_PREPEND_SELF)
+		    set->type != ACTION_SET_PREPEND_SELF &&
+		    set->type != ACTION_SET_NEXTHOP_NOMODIFY)
 			continue;
 
 		switch (set->type) {
@@ -119,6 +120,10 @@ rde_apply_set(struct rde_aspath *asp, struct filter_set_head *sh,
 		case ACTION_SET_NEXTHOP:
 		case ACTION_SET_NEXTHOP_REJECT:
 		case ACTION_SET_NEXTHOP_BLACKHOLE:
+		case ACTION_SET_NEXTHOP_NOMODIFY:
+			if (set->type == ACTION_SET_NEXTHOP_NOMODIFY &&
+			    dir == DIR_DEFAULT_IN)
+				break;
 			nexthop_modify(asp, &set->action.nexthop, set->type,
 			    af);
 			break;
diff --git a/usr.sbin/bgpd/rde_rib.c b/usr.sbin/bgpd/rde_rib.c
index 5e9dbc4830f..ea3295164d2 100644
--- a/usr.sbin/bgpd/rde_rib.c
+++ b/usr.sbin/bgpd/rde_rib.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rde_rib.c,v 1.63 2004/11/23 13:07:01 claudio Exp $ */
+/*	$OpenBSD: rde_rib.c,v 1.64 2005/03/11 12:54:20 claudio Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Claudio Jeker <claudio@openbsd.org>
@@ -762,6 +762,10 @@ nexthop_modify(struct rde_aspath *asp, struct bgpd_addr *nexthop,
 		asp->flags |= F_NEXTHOP_BLACKHOLE;
 		return;
 	}
+	if (type == ACTION_SET_NEXTHOP_NOMODIFY) {
+		asp->flags |= F_NEXTHOP_NOMODIFY;
+		return;
+	}
 	if (af != nexthop->af)
 		return;
 
diff --git a/usr.sbin/bgpd/rde_update.c b/usr.sbin/bgpd/rde_update.c
index 1533196be94..5fd755b298e 100644
--- a/usr.sbin/bgpd/rde_update.c
+++ b/usr.sbin/bgpd/rde_update.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rde_update.c,v 1.34 2005/02/07 05:51:52 david Exp $ */
+/*	$OpenBSD: rde_update.c,v 1.35 2005/03/11 12:54:20 claudio Exp $ */
 
 /*
  * Copyright (c) 2004 Claudio Jeker <claudio@openbsd.org>
@@ -580,7 +580,12 @@ up_generate_attr(struct rde_peer *peer, struct update_attr *upa,
 	wlen += r; len -= r;
 
 	/* aspath */
-	path = aspath_prepend(a->aspath, rde_local_as(), peer->conf.ebgp);
+	if (!peer->conf.ebgp ||
+	    rde_decisionflags() & BGPD_FLAG_DECISION_TRANS_AS)
+		path = aspath_prepend(a->aspath, rde_local_as(), 0);
+	else
+		path = aspath_prepend(a->aspath, rde_local_as(), 1);
+
 	if ((r = attr_write(up_attr_buf + wlen, len, ATTR_WELL_KNOWN,
 	    ATTR_ASPATH, path->data, path->len)) == -1)
 		return (-1);
@@ -588,7 +593,13 @@ up_generate_attr(struct rde_peer *peer, struct update_attr *upa,
 	wlen += r; len -= r;
 
 	/* nexthop, already network byte order */
-	if (peer->conf.ebgp == 0) {
+	if (a->flags & F_NEXTHOP_NOMODIFY) {
+		/* no modify flag set */
+		if (a->nexthop == NULL)
+			nexthop = peer->local_v4_addr.v4.s_addr;
+		else
+			nexthop = a->nexthop->exit_nexthop.v4.s_addr;
+	} else if (!peer->conf.ebgp) {
 		/*
 		 * If directly connected use peer->local_v4_addr
 		 * this is only true for announced networks.