From be6e39ebbf7ed107abde6fc1a18e8827ca47a7c1 Mon Sep 17 00:00:00 2001
From: Ondrej Zajicek <santiago@crfreenet.org>
Date: Thu, 24 Sep 2009 22:12:11 +0200
Subject: Passive option.

---
 doc/bird.sgml      | 5 +++++
 proto/bgp/bgp.c    | 7 +++++--
 proto/bgp/bgp.h    | 1 +
 proto/bgp/config.Y | 4 ++--
 4 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/doc/bird.sgml b/doc/bird.sgml
index 258b842..ceff31d 100644
--- a/doc/bird.sgml
+++ b/doc/bird.sgml
@@ -868,6 +868,11 @@ for each neighbor using the following configuration parameters:
 	of BGP sessions. Default: no authentication. Password has to be set by
 	external utility (e.g. setkey(8)) on BSD systems.
 
+	<tag>passive <m/switch/</tag> Standard BGP behavior is both
+        initiating outgoing connections and accepting incoming
+        connections. In passive mode, outgoing connections are not
+        initiated. Default: off.
+
 	<tag>rr client</tag> Be a route reflector and treat the neighbor as
 	a route reflection client. Default: disabled.
 
diff --git a/proto/bgp/bgp.c b/proto/bgp/bgp.c
index 0c8ee6d..af5dbfc 100644
--- a/proto/bgp/bgp.c
+++ b/proto/bgp/bgp.c
@@ -120,7 +120,9 @@ bgp_startup(struct bgp_proto *p)
 {
   BGP_TRACE(D_EVENTS, "Started");
   p->start_state = p->cf->capabilities ? BSS_CONNECT : BSS_CONNECT_NOCAP;
-  bgp_active(p);
+
+  if (!p->cf->passive)
+    bgp_active(p);
 }
 
 static void
@@ -292,7 +294,8 @@ bgp_decision(void *vp)
 
   DBG("BGP: Decision start\n");
   if ((p->p.proto_state == PS_START)
-      && (p->outgoing_conn.state == BS_IDLE))
+      && (p->outgoing_conn.state == BS_IDLE)
+      && (!p->cf->passive))
     bgp_active(p);
 
   if ((p->p.proto_state == PS_STOP)
diff --git a/proto/bgp/bgp.h b/proto/bgp/bgp.h
index 092c3b3..0a82be2 100644
--- a/proto/bgp/bgp.h
+++ b/proto/bgp/bgp.h
@@ -33,6 +33,7 @@ struct bgp_config {
   int rs_client;			/* Whether neighbor is RS client of me */
   int advertise_ipv4;			/* Whether we should add IPv4 capability advertisement to OPEN message */
   u32 route_limit;			/* Number of routes that may be imported, 0 means disable limit */
+  int passive;				/* Do not initiate outgoing connection */
   unsigned connect_retry_time;
   unsigned hold_time, initial_hold_time;
   unsigned keepalive_time;
diff --git a/proto/bgp/config.Y b/proto/bgp/config.Y
index 872fb27..7360820 100644
--- a/proto/bgp/config.Y
+++ b/proto/bgp/config.Y
@@ -22,7 +22,7 @@ CF_KEYWORDS(BGP, LOCAL, NEIGHBOR, AS, HOLD, TIME, CONNECT, RETRY, KEEPALIVE,
 	BGP_PATH, BGP_LOCAL_PREF, BGP_MED, BGP_ORIGIN, BGP_NEXT_HOP,
 	BGP_ATOMIC_AGGR, BGP_AGGREGATOR, BGP_COMMUNITY, SOURCE, ADDRESS,
 	PASSWORD, RR, RS, CLIENT, CLUSTER, ID, AS4, ADVERTISE, IPV4,
-	CAPABILITIES, LIMIT)
+	CAPABILITIES, LIMIT, PASSIVE)
 
 CF_GRAMMAR
 
@@ -34,7 +34,6 @@ bgp_proto_start: proto_start BGP {
      BGP_CFG->hold_time = 240;
      BGP_CFG->connect_retry_time = 120;
      BGP_CFG->initial_hold_time = 240;
-     BGP_CFG->default_med = 0;
      BGP_CFG->compare_path_lengths = 1;
      BGP_CFG->start_delay_time = 5;
      BGP_CFG->error_amnesia_time = 300;
@@ -78,6 +77,7 @@ bgp_proto:
  | bgp_proto ADVERTISE IPV4 bool ';' { BGP_CFG->advertise_ipv4 = $4; }
  | bgp_proto PASSWORD TEXT ';' { BGP_CFG->password = $3; }
  | bgp_proto ROUTE LIMIT expr ';' { BGP_CFG->route_limit = $4; }
+ | bgp_proto PASSIVE bool ';' { BGP_CFG->passive = $3; }
  ;
 
 CF_ADDTO(dynamic_attr, BGP_PATH
-- 
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