bgpd: When advertising a multipath route, the attribute set to be

advertised is based on the bestpath attribute set, but the
following attributes are aggregated from the attribute sets
of the multipath constituents:
- AS_PATH
- ORIGIN
- COMMUNITIES
- EXTENDED COMMUNITIES

In addition the route is advertised with the NEXT_HOP set
to the router's interface IP address, instead of the NEXT_HOP
of the best path. This is to ensure that traffic will go to this
router so it can be fanned out via the multipath route.

* bgpd/ecommunity.c
  * ecommunity_uniq_sort(): Make this function externally accessible
* bgpd/ecommunity.h
  * Add external declaration for ecommunity_uniq_sort()
* bgpd/bgp_mpath.c
  * bgp_info_nexthop_cmp(): Replace calls to bgp_attr_extra_get()
    to avoid unwanted memory allocation
  * bgp_info_mpath_free(): Free aggregate attribute for multipath
  * bgp_info_mpath_attr(): Lookup aggregate attribute of a multipath route
  * bgp_info_mpath_attr_set(): Set aggregate attribute of a multipath route
  * bgp_info_mpath_aggregate_update(): Update the aggregate attribute
    of a multipath route
* bgpd/bgp_mpath.h
  * bgp_info_mpath: Add pointer to hold aggregate attribute of a multipath
  * Add external declarations for new functions
* bgpd/bgp_route.c
  * bgp_announce_check(): Use aggregate attribute when announcing multipath
    route
  * bgp_announce_check_rsclient(): Use aggregate attribute when announcing
    multipath route
  * bgp_best_selection(): After updating multipath set, update the
    multipath aggregate attribute

1 files changed, 6 insertions, 0 deletions

diff --git a/bgpd/bgp_mpath.h b/bgpd/bgp_mpath.h
index 3712493e..37b9ac8b 100644
--- a/bgpd/bgp_mpath.h
+++ b/bgpd/bgp_mpath.h
@@ -43,6 +43,9 @@ struct bgp_info_mpath
 
   /* When attached to best path, the number of selected multipaths */
   u_int32_t mp_count;
+
+  /* Aggregated attribute for advertising multipath route */
+  struct attr *mp_attr;
 };
 
 /* Functions to support maximum-paths configuration */
@@ -59,6 +62,8 @@ extern void bgp_mp_dmed_deselect (struct bgp_info *);
 extern void bgp_info_mpath_update (struct bgp_node *, struct bgp_info *,
                                    struct bgp_info *, struct list *,
                                    struct bgp_maxpaths_cfg *);
+extern void bgp_info_mpath_aggregate_update (struct bgp_info *,
+                                             struct bgp_info *);
 
 /* Unlink and free multipath information associated with a bgp_info */
 extern void bgp_info_mpath_dequeue (struct bgp_info *);
@@ -70,5 +75,6 @@ extern struct bgp_info *bgp_info_mpath_next (struct bgp_info *);
 
 /* Accessors for multipath information */
 extern u_int32_t bgp_info_mpath_count (struct bgp_info *);
+extern struct attr *bgp_info_mpath_attr (struct bgp_info *);
 
 #endif /* _QUAGGA_BGP_MPATH_H */