Implementation of route server.

doc/bird.sgml

@@ -62,9 +62,10 @@ a statically configured table.
 <p>A <em/Routing Daemon/ is in UNIX terminology a non-interactive program running on
 background which does the dynamic part of Internet routing, that is it communicates
 with the other routers, calculates routing tables and sends them to the OS kernel
-which does the actual packet forwarding. There already exist other such routing daemons: routed (RIP only), GateD<HTMLURL URL="http://www.gated.org/">
+which does the actual packet forwarding. There already exist other such routing
- (non-free), Zebra<HTMLURL URL="http://www.zebra.org"> and MRTD<HTMLURL URL="http://www.zcu.cz/ftp/mirrors/mmrz/mrtd">, but their capabilities are limited and
+daemons: routed (RIP only), GateD (non-free), Zebra<HTMLURL URL="http://www.zebra.org">
-they are relatively hard to configure and maintain.
+and MRTD<HTMLURL URL="http://sourceforge.net/projects/mrt">, but their capabilities are
+limited and they are relatively hard to configure and maintain.
 
 <p>BIRD is an Internet Routing Daemon designed to avoid all of these shortcomings,
 to support all the routing technology used in the today's Internet or planned to be
@@ -730,8 +731,8 @@ for each neighbor using the following configuration parameters:
 	<tag>password <m/string/</tag> Use this password for MD5 authentication
 	of BGP sessions. Default: no authentication.
 
-	<tag>rr client</tag> Be a route reflector and treat neighbor as
+	<tag>rr client</tag> Be a route reflector and treat the neighbor as
-	route reflection client. Default: disabled.
+	a route reflection client. Default: disabled.
 
 	<tag>rr cluster id <m/IPv4 address/</tag> Route reflectors use cluster id
 	to avoid route reflection loops. When there is one route reflector in a cluster
@@ -740,6 +741,15 @@ for each neighbor using the following configuration parameters:
 	use a common cluster id. Clients in a cluster need not known their cluster
 	id and this option is not allowed to them  Default: a same as router id.
 
+	<tag>rs client</tag> Be a route server and treat the neighbor
+	as a route server client. A route server is used as a
+	replacement for full mesh EBGP routing in Internet exchange
+	points in a similar way to route reflectors used in IBGP routing.
+	Bird does not implement obsoleted RFC 1863, but uses ad-hoc implementation,
+	which behaves like plain EBGP but reduces modifications to advertised route
+	attributes to be transparent (for example does not prepend its AS number to
+	AS PATH attribute and keep MED attribute). Default: disabled.
+
 	<tag>enable as4 <m/switch/</tag> BGP protocol was designed to use 2B AS numbers
 	and was extended later to allow 4B AS number. BIRD supports 4B AS extension,
 	but by disabling this option it can be persuaded not to advertise it and

proto/bgp/attrs.c

@@ -828,7 +828,7 @@ bgp_update_attrs(struct bgp_proto *p, rte *e, ea_list **attrs, struct linpool *p
 {
   eattr *a;
 
-  if (!p->is_internal)
+  if (!p->is_internal && !p->rs_client)
     {
       bgp_path_prepend(e, attrs, pool, p->local_as);
 

proto/bgp/bgp.c

@@ -492,6 +492,8 @@ bgp_start_locked(struct object_lock *lock)
       p->rr_client = cf->rr_client;
     }
 
+  p->rs_client = cf->rs_client;
+
   if (!p->neigh)
     {
       log(L_ERR "%s: Invalid next hop %I", p->p.name, p->next_hop);
@@ -644,6 +646,8 @@ bgp_check(struct bgp_config *c)
     cf_error("Neighbor AS number out of range");
   if ((c->local_as != c->remote_as) && (c->rr_client))
     cf_error("Only internal neighbor can be RR client");
+  if ((c->local_as == c->remote_as) && (c->rs_client))
+    cf_error("Only external neighbor can be RS client");
 }
 
 static void

proto/bgp/bgp.h

@@ -28,6 +28,7 @@ struct bgp_config {
   int enable_as4;			/* Enable local support for 4B AS numbers [RFC4893] */
   u32 rr_cluster_id;			/* Route reflector cluster ID, if different from local ID */
   int rr_client;			/* Whether neighbor is RR client of me */
+  int rs_client;			/* Whether neighbor is RS client of me */
   unsigned connect_retry_time;
   unsigned hold_time, initial_hold_time;
   unsigned keepalive_time;
@@ -66,6 +67,7 @@ struct bgp_proto {
   u32 remote_id;			/* BGP identifier of the neighbor */
   u32 rr_cluster_id;			/* Route reflector cluster ID */
   int rr_client;			/* Whether neighbor is RR client of me */
+  int rs_client;			/* Whether neighbor is RS client of me */
   struct bgp_conn *conn;		/* Connection we have established */
   struct bgp_conn outgoing_conn;	/* Outgoing connection we're working with */
   struct bgp_conn incoming_conn;	/* Incoming connection we have neither accepted nor rejected yet */

proto/bgp/config.Y

@@ -21,7 +21,7 @@ CF_KEYWORDS(BGP, LOCAL, NEIGHBOR, AS, HOLD, TIME, CONNECT, RETRY, KEEPALIVE,
 	ERROR, START, DELAY, FORGET, WAIT, ENABLE, DISABLE, AFTER,
 	BGP_PATH, BGP_LOCAL_PREF, BGP_MED, BGP_ORIGIN, BGP_NEXT_HOP,
 	BGP_ATOMIC_AGGR, BGP_AGGREGATOR, BGP_COMMUNITY, SOURCE, ADDRESS,
-	PASSWORD, RR, CLIENT, CLUSTER, ID, AS4)
+	PASSWORD, RR, RS, CLIENT, CLUSTER, ID, AS4)
 
 CF_GRAMMAR
 
@@ -55,6 +55,7 @@ bgp_proto:
    }
  | bgp_proto RR CLUSTER ID expr ';' { BGP_CFG->rr_cluster_id = $5; }
  | bgp_proto RR CLIENT ';' { BGP_CFG->rr_client = 1; }
+ | bgp_proto RS CLIENT ';' { BGP_CFG->rs_client = 1; }
  | bgp_proto HOLD TIME expr ';' { BGP_CFG->hold_time = $4; }
  | bgp_proto STARTUP HOLD TIME expr ';' { BGP_CFG->initial_hold_time = $5; }
  | bgp_proto CONNECT RETRY TIME expr ';' { BGP_CFG->connect_retry_time = $5; }