From 93a508df6028dc838117d620f0daee6c6d15ccbf Mon Sep 17 00:00:00 2001
From: Matthias Schiffer <mschiffer@universe-factory.net>
Date: Thu, 8 Dec 2011 09:00:13 +0100
Subject: BGP: Add support for specifying interface names to allow peerings
 using link-local addresses

---
 proto/bgp/bgp.c     | 6 ++++--
 proto/bgp/bgp.h     | 1 +
 proto/bgp/config.Y  | 3 ++-
 proto/bgp/packets.c | 3 +++
 4 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/proto/bgp/bgp.c b/proto/bgp/bgp.c
index 675342d..e537fce 100644
--- a/proto/bgp/bgp.c
+++ b/proto/bgp/bgp.c
@@ -579,6 +579,7 @@ bgp_connect(struct bgp_proto *p)	/* Enter Connect state and start establishing c
   s->saddr = p->source_addr;
   s->daddr = p->cf->remote_ip;
   s->dport = BGP_PORT;
+  s->iface = p->neigh->iface;
   s->ttl = p->cf->ttl_security ? 255 : hops;
   s->rbsize = BGP_RX_BUFFER_SIZE;
   s->tbsize = BGP_TX_BUFFER_SIZE;
@@ -793,7 +794,7 @@ bgp_start_locked(struct object_lock *lock)
       return;
     }
 
-  p->neigh = neigh_find(&p->p, &cf->remote_ip, NEF_STICKY);
+  p->neigh = neigh_find_ifname(&p->p, &cf->remote_ip, (*cf->interface) ? cf->interface : NULL, NEF_STICKY);
   if (!p->neigh || (p->neigh->scope == SCOPE_HOST))
     {
       log(L_ERR "%s: Invalid remote address %I", p->p.name, cf->remote_ip);
@@ -807,7 +808,7 @@ bgp_start_locked(struct object_lock *lock)
   if (p->neigh->iface)
     bgp_start_neighbor(p);
   else
-    BGP_TRACE(D_EVENTS, "Waiting for %I to become my neighbor", cf->remote_ip);
+    BGP_TRACE(D_EVENTS, "Waiting for %I to become my neighbor%s%s", cf->remote_ip, (*cf->interface) ? " on " : "", cf->interface);
 }
 
 static int
@@ -852,6 +853,7 @@ bgp_start(struct proto *P)
   lock->iface = NULL;
   lock->hook = bgp_start_locked;
   lock->data = p;
+
   olock_acquire(lock);
 
   return PS_START;
diff --git a/proto/bgp/bgp.h b/proto/bgp/bgp.h
index 437ba33..e8fcdbb 100644
--- a/proto/bgp/bgp.h
+++ b/proto/bgp/bgp.h
@@ -49,6 +49,7 @@ struct bgp_config {
   unsigned error_delay_time_min;	/* Time to wait after an error is detected */
   unsigned error_delay_time_max;
   unsigned disable_after_error;		/* Disable the protocol when error is detected */
+  char interface[16];			/* Interface to use */
   char *password;			/* Password used for MD5 authentication */
   struct rtable_config *igp_table;	/* Table used for recursive next hop lookups */
 };
diff --git a/proto/bgp/config.Y b/proto/bgp/config.Y
index 03c233d..f943ea5 100644
--- a/proto/bgp/config.Y
+++ b/proto/bgp/config.Y
@@ -25,7 +25,7 @@ CF_KEYWORDS(BGP, LOCAL, NEIGHBOR, AS, HOLD, TIME, CONNECT, RETRY,
 	CLUSTER, ID, AS4, ADVERTISE, IPV4, CAPABILITIES, LIMIT, PASSIVE,
 	PREFER, OLDER, MISSING, LLADDR, DROP, IGNORE, ROUTE, REFRESH,
 	INTERPRET, COMMUNITIES, BGP_ORIGINATOR_ID, BGP_CLUSTER_LIST, IGP,
-	TABLE, GATEWAY, DIRECT, RECURSIVE, MED, TTL, SECURITY)
+	TABLE, GATEWAY, DIRECT, RECURSIVE, MED, TTL, SECURITY, INTERFACE)
 
 CF_GRAMMAR
 
@@ -99,6 +99,7 @@ bgp_proto:
  | bgp_proto INTERPRET COMMUNITIES bool ';' { BGP_CFG->interpret_communities = $4; }
  | bgp_proto IGP TABLE rtable ';' { BGP_CFG->igp_table = $4; }
  | bgp_proto TTL SECURITY bool ';' { BGP_CFG->ttl_security = $4; }
+ | bgp_proto INTERFACE TEXT ';' { strncpy(BGP_CFG->interface, $3, sizeof(BGP_CFG->interface)-1); }
  ;
 
 CF_ADDTO(dynamic_attr, BGP_ORIGIN
diff --git a/proto/bgp/packets.c b/proto/bgp/packets.c
index c3a8673..7d78d9f 100644
--- a/proto/bgp/packets.c
+++ b/proto/bgp/packets.c
@@ -434,6 +434,9 @@ bgp_create_update(struct bgp_conn *conn, byte *buf)
 	  *tmp++ = BGP_AF_IPV6;
 	  *tmp++ = 1;
 
+	  if (ipa_has_link_scope(ip))
+	    ip = IPA_NONE;
+
 	  if (ipa_nonzero(ip_ll))
 	    {
 	      *tmp++ = 32;
-- 
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