zebra: Fix zebra crashed in building FPM netlink message when bgp sends aggregation...

Issue:
    When BGP sends aggregation routes to zebra, the next hop is black hole.
    Then Zebra will try to build the netlink FPM message, but there is no
    next hop as it is a black hole route. Then the netlink_route_info_fill
    function returns 0. In the result, zebra will crashed in
    "assert(data_len)" of zfpm_build_route_updates.
    This issue also happen when I create a static black hole route via
    staticd.
Fix:
    As the netlink message of the blackhole route is legal, it should return
    success.

Signed-off-by: Richard Wu <wutong23@baidu.com>

diff --git a/zebra/zebra_fpm_netlink.c b/zebra/zebra_fpm_netlink.c
index c580fe40d57d74944e13ddee39cb650b09568660..b194f80fc72a946cfddeb95e455a57ef9781a220 100644 (file)
--- a/zebra/zebra_fpm_netlink.c
+++ b/zebra/zebra_fpm_netlink.c
@@ -339,7 +339,7 @@ static int netlink_route_info_fill(struct netlink_route_info *ri, int cmd,
        }
 
        /* If there is no useful nexthop then return. */
-       if (ri->num_nhs == 0) {
+       if (ri->rtm_type != RTN_BLACKHOLE && ri->num_nhs == 0) {
                zfpm_debug("netlink_encode_route(): No useful nexthop.");
                return 0;
        }