From ad440a570b37e8674ef35f3a18df48f0eb2579eb Mon Sep 17 00:00:00 2001
From: Ondrej Zajicek <santiago@crfreenet.org>
Date: Tue, 28 Apr 2009 18:11:56 +0200
Subject: [PATCH] Fixes handling of 'next hop self' and 'source address'
 configuration options.

---
 proto/bgp/attrs.c   | 11 +++--------
 proto/bgp/bgp.c     |  9 ++++-----
 proto/bgp/bgp.h     |  1 +
 proto/bgp/packets.c |  2 +-
 4 files changed, 9 insertions(+), 14 deletions(-)

diff --git a/proto/bgp/attrs.c b/proto/bgp/attrs.c
index a015c2b3..9a247dec 100644
--- a/proto/bgp/attrs.c
+++ b/proto/bgp/attrs.c
@@ -790,12 +790,7 @@ bgp_create_attrs(struct bgp_proto *p, rte *e, ea_list **attrs, struct linpool *p
   if (p->cf->next_hop_self ||
       !p->is_internal ||
       rta->dest != RTD_ROUTER)
-    {
-      if (ipa_nonzero(p->cf->source_addr))
-        *(ip_addr *)z = p->cf->source_addr;
-      else
-        *(ip_addr *)z = p->local_addr;
-    }
+    *(ip_addr *)z = p->source_addr;
   else
     *(ip_addr *)z = e->attrs->gw;
 
@@ -860,14 +855,14 @@ bgp_update_attrs(struct bgp_proto *p, rte *e, ea_list **attrs, struct linpool *p
     }
 
   a = ea_find(e->attrs->eattrs, EA_CODE(EAP_BGP, BA_NEXT_HOP));
-  if (a && (p->is_internal || (!p->is_internal && e->attrs->iface == p->neigh->iface)))
+  if (a && !p->cf->next_hop_self && (p->is_internal || (!p->is_internal && e->attrs->iface == p->neigh->iface)))
     {
       /* Leave the original next hop attribute, will check later where does it point */
     }
   else
     {
       /* Need to create new one */
-      bgp_attach_attr_ip(attrs, pool, BA_NEXT_HOP, p->local_addr);
+      bgp_attach_attr_ip(attrs, pool, BA_NEXT_HOP, p->source_addr);
     }
 
   if (rr)
diff --git a/proto/bgp/bgp.c b/proto/bgp/bgp.c
index 41c8d533..a0bc8923 100644
--- a/proto/bgp/bgp.c
+++ b/proto/bgp/bgp.c
@@ -500,10 +500,7 @@ bgp_connect(struct bgp_proto *p)	/* Enter Connect state and start establishing c
   DBG("BGP: Connecting\n");
   s = sk_new(p->p.pool);
   s->type = SK_TCP_ACTIVE;
-  if (ipa_nonzero(p->cf->source_addr))
-    s->saddr = p->cf->source_addr;
-  else
-    s->saddr = p->local_addr;
+  s->saddr = p->source_addr;
   s->daddr = p->cf->remote_ip;
   s->dport = BGP_PORT;
   s->ttl = p->cf->multihop ? : 1;
@@ -609,7 +606,9 @@ static void
 bgp_start_neighbor(struct bgp_proto *p)
 {
   p->local_addr = p->neigh->iface->addr->ip;
-  DBG("BGP: local=%I remote=%I\n", p->local_addr, p->next_hop);
+  p->source_addr = ipa_nonzero(p->cf->source_addr) ? p->cf->source_addr : p->local_addr;
+
+  DBG("BGP: local=%I remote=%I\n", p->source_addr, p->next_hop);
 #ifdef IPV6
   {
     struct ifa *a;
diff --git a/proto/bgp/bgp.h b/proto/bgp/bgp.h
index d5448a68..83ed9c75 100644
--- a/proto/bgp/bgp.h
+++ b/proto/bgp/bgp.h
@@ -79,6 +79,7 @@ struct bgp_proto {
   ip_addr next_hop;			/* Either the peer or multihop_via */
   struct neighbor *neigh;		/* Neighbor entry corresponding to next_hop */
   ip_addr local_addr;			/* Address of the local end of the link to next_hop */
+  ip_addr source_addr;			/* Address used as advertised next hop, usually local_addr */
   struct event *event;			/* Event for respawning and shutting process */
   struct bgp_bucket **bucket_hash;	/* Hash table of attribute buckets */
   unsigned int hash_size, hash_count, hash_limit;
diff --git a/proto/bgp/packets.c b/proto/bgp/packets.c
index 1370ee70..93cabbec 100644
--- a/proto/bgp/packets.c
+++ b/proto/bgp/packets.c
@@ -293,7 +293,7 @@ bgp_create_update(struct bgp_conn *conn, byte *buf)
 	  ASSERT(nh);
 	  ip = *(ip_addr *) nh->u.ptr->data;
 	  is_ll = 0;
-	  if (ipa_equal(ip, p->local_addr))
+	  if (ipa_equal(ip, p->source_addr))
 	    {
 	      is_ll = 1;
 	      ip_ll = p->local_link;