bgpd: Ensure mpath data is only on bestpath

The mpath data structure has data that is only relevant
for the first mpath in the list.  It is not being used
anywhere else.  Let's document that a bit more.

Signed-off-by: Donald Sharp <sharpd@nvidia.com>

diff --git a/bgpd/bgp_mpath.c b/bgpd/bgp_mpath.c
index 3421b00ba75ba03ceded8fcf41963c38fc5eaa45..3b8b2745566397c5c26f813bc8c30d08a3fbe703 100644 (file)
--- a/bgpd/bgp_mpath.c
+++ b/bgpd/bgp_mpath.c
@@ -411,6 +411,10 @@ static void bgp_path_info_mpath_count_set(struct bgp_path_info *path,
  * bgp_path_info_mpath_lb_update
  *
  * Update cumulative info related to link-bandwidth
+ *
+ * This is only set on the first mpath of the list
+ * as such we should UNSET the flags when removing
+ * to ensure nothing accidently happens
  */
 static void bgp_path_info_mpath_lb_update(struct bgp_path_info *path, bool set,
                                          bool all_paths_lb, uint64_t cum_bw)

diff --git a/bgpd/bgp_mpath.h b/bgpd/bgp_mpath.h
index 129682d1dc19c3c796fa8fb5e45da1b35af3eef1..267d729e06d446a0b2bb57f56dce3921634e8970 100644 (file)
--- a/bgpd/bgp_mpath.h
+++ b/bgpd/bgp_mpath.h
@@ -25,15 +25,18 @@ struct bgp_path_info_mpath {
        /* When attached to best path, the number of selected multipaths */
        uint16_t mp_count;
 
-       /* Flags - relevant as noted. */
+       /* Flags - relevant as noted, attached to bestpath. */
        uint16_t mp_flags;
 #define BGP_MP_LB_PRESENT 0x1 /* Link-bandwidth present for >= 1 path */
 #define BGP_MP_LB_ALL 0x2 /* Link-bandwidth present for all multipaths */
 
-       /* Aggregated attribute for advertising multipath route */
+       /*
+        * Aggregated attribute for advertising multipath route,
+        * attached to bestpath
+        */
        struct attr *mp_attr;
 
-       /* Cumulative bandiwdth of all multipaths - attached to best path. */
+       /* Cumulative bandiwdth of all multipaths - attached to bestpath. */
        uint64_t cum_bw;
 };