bgpd: fix colored routes not installed after a switchover

On a multihomed setup with colored bgp updates, when the primary
PE goes offline, only a small subset of colored bgp routes are
not switching to the secondary pe.

When a switchover happens, due to a remote IP becoming unreachable,
some nexthop tracking down notifications are sent, but those messages
are completely ignored for colored bgp updates.

The original code has been thought for mounting up the SR-TE service,
when IP reachability is ok, but not when services goes offline.

Fix this by extending the down notification mechanism for colored routes
too.

Fixes: 545aeef ("bgpd: extend the NHT code to understand SR-TE colors")

Signed-off-by: Philippe Guibert <[email protected]>

bgpd/bgp_nht.c

@@ -978,8 +978,7 @@ void bgp_nexthop_update(struct vrf *vrf, struct prefix *match,
 		frr_each (bgp_nexthop_cache, &bgp->nexthop_cache_table[afi],
 			  bnc_iter) {
 			if (!prefix_same(match, &bnc_iter->prefix) ||
-			    bnc_iter->srte_color == 0 ||
-			    CHECK_FLAG(bnc_iter->flags, BGP_NEXTHOP_VALID))
+			    bnc_iter->srte_color == 0)
 				continue;
 
 			bgp_process_nexthop_update(bnc_iter, nhr, false);