bgpd: track correct originator-id in reflected routes

ISSUE:

Suppose route1 and route2 received from route-reflector-client1 and client2
respectively have identical attributes. The current logic of creating the
adj-rib-out for a peer threads the 'adv' structures for both routes against
the same attribute. This results in 'bgp_update_packet()' to pack those
routes in the same UPDATE message with one attr structure formatted. The
originator-id is thus set according to the first route's received router id.
This is incorrect.

PATCH:

Fix bgp_announce_check() function to set the originator-id in the
advertising attr structure. Also, fix the attribute hash function and
compare function to consider originator-id. Otherwise attributes where all
fields except the originator-id are identical get merged into one memory
location.

Signed-off-by: Pradosh Mohapatra <pmohapat at cumulusnetworks.com>
Reviewed-by: Scott Feldman <sfeldma at cumulusnetworks.com>
Reviewed-by: Ken Yin <kyin at cumulusnetworks.com>
[DL: whitespace changes dropped]
Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
diff --git a/bgpd/bgp_route.c b/bgpd/bgp_route.c
index 7f68b8d..0428531 100644
--- a/bgpd/bgp_route.c
+++ b/bgpd/bgp_route.c
@@ -965,6 +965,17 @@
       attr->local_pref = bgp->default_local_pref;
     }
 
+  /* If originator-id is not set and the route is to be reflected,
+     set the originator id */
+  if (peer && from && peer->sort == BGP_PEER_IBGP &&
+      from->sort == BGP_PEER_IBGP &&
+      (! (attr->flag & ATTR_FLAG_BIT(BGP_ATTR_ORIGINATOR_ID))))
+    {
+      attr->extra = bgp_attr_extra_get(attr);
+      IPV4_ADDR_COPY(&(attr->extra->originator_id), &(from->remote_id));
+      SET_FLAG(attr->flag, BGP_ATTR_ORIGINATOR_ID);
+    }
+
   /* Remove MED if its an EBGP peer - will get overwritten by route-maps */
   if (peer->sort == BGP_PEER_EBGP
       && attr->flag & ATTR_FLAG_BIT (BGP_ATTR_MULTI_EXIT_DISC))