Avoid creating neighbor with same address as another.

With bgp multiple-instance it was possible to create a neighbor in one
"view" with the same addres as a neighbor in another view (or the main,
unnamed view).

To do so was a mistake, since (in particular) the accept() mechanism
depends on finding the neighbor by its address -- so two neighbors with
the same address == confusion.

Attempting to create two neighbors with the same address is now
treated as an error, at the command level.

Also, added "-rdynamic" to the CFLAGS for gcc in configure.ac.  This
improves the output from the stack traceback in the event of an
assert or other failure.

4 files changed, 14 insertions, 2 deletions

diff --git a/bgpd/bgp_vty.c b/bgpd/bgp_vty.c
index d99638b2..222e4485 100644
--- a/bgpd/bgp_vty.c
+++ b/bgpd/bgp_vty.c
@@ -219,6 +219,9 @@ bgp_vty_return (struct vty *vty, int ret)
     case BGP_ERR_TCPSIG_FAILED:
       str = "Error while applying TCP-Sig to session(s)";
       break;
+    case BGP_ERR_PEER_EXISTS:
+      str = "Cannot have the same neighbor in different bgp views";
+      break;
     }
   if (str)
     {
diff --git a/bgpd/bgpd.c b/bgpd/bgpd.c
index 30b882b6..f9e2ed93 100644
--- a/bgpd/bgpd.c
+++ b/bgpd/bgpd.c
@@ -761,6 +761,10 @@ peer_remote_as (struct bgp *bgp, union sockunion *su, as_t *as,
       else
 	local_as = bgp->as;
 
+      /* Check that the neighbor IP is unique                           */
+      if (peer_lookup (NULL, su) != NULL)
+        return BGP_ERR_PEER_EXISTS ;
+
       /* TODO: report bug...  if is IPv4 unicast, may implicitly activate  */
 
       /* If this is IPv4 unicast configuration and "no bgp default
@@ -1340,6 +1344,10 @@ peer_group_bind (struct bgp *bgp, union sockunion *su,
       if (! group->conf->as)
 	return BGP_ERR_PEER_GROUP_NO_REMOTE_AS;
 
+      /* Check that the neighbor IP is unique                           */
+      if (peer_lookup (NULL, su) != NULL)
+        return BGP_ERR_PEER_EXISTS ;
+
       peer = bgp_peer_create (su, bgp, bgp->as, group->conf->as, afi, safi);
       peer->group = group;
       peer->af_group[afi][safi] = 1;
diff --git a/bgpd/bgpd.h b/bgpd/bgpd.h
index 7a53c511..ee8efa1b 100644
--- a/bgpd/bgpd.h
+++ b/bgpd/bgpd.h
@@ -398,7 +398,8 @@ enum bgp_clear_type
 #define BGP_ERR_LOCAL_AS_ALLOWED_ONLY_FOR_EBGP  -27
 #define BGP_ERR_CANNOT_HAVE_LOCAL_AS_SAME_AS    -28
 #define BGP_ERR_TCPSIG_FAILED			-29
-#define BGP_ERR_MAX                             -30
+#define BGP_ERR_PEER_EXISTS                     -30
+#define BGP_ERR_MAX                             -31
 
 extern struct bgp_master *bm;
 
diff --git a/configure.ac b/configure.ac
index b34c69ff..865e84ed 100755
--- a/configure.ac
+++ b/configure.ac
@@ -128,7 +128,7 @@ if test "x${cflags_specified}" = "x" ; then
   	CFLAGS="${CFLAGS} -Wbad-function-cast -Wwrite-strings"
   	CFLAGS="${CFLAGS} -Wmissing-prototypes -Wmissing-declarations"
   	CFLAGS="${CFLAGS} -Wchar-subscripts -Wcast-qual"
-  	CFLAGS="${CFLAGS} -pthread"
+  	CFLAGS="${CFLAGS} -pthread -rdynamic"
   	# TODO: conditionally addd -Wpacked if handled
   	AC_MSG_RESULT([gcc default])
   	;;