From: liuze03 <liuze03@baidu.com>
Date: Wed, 7 Dec 2022 04:22:43 +0000 (+0800)
Subject:     bgpd: Fix aggregated routes are withdrawn abnormally.
X-Git-Tag: docker/8.4.2~4^2
X-Git-Url: https://git.puffer.fish/?a=commitdiff_plain;h=2865946b03feada837020d6dcbca06f28581efc8;p=matthieu%2Ffrr.git

bgpd: Fix aggregated routes are withdrawn abnormally.

    The withdraw message and announcement message of a prefix are received continuously within 50ms, which may lead to abnormal aggregation route reference count.
    Steps to reproduce:
    --------------------------
    step1:
    local config aggregate route 111.0.0.0/24
    received route：111.0.0.1/32 111.0.0.02/32
    ref_count:2

    step2:
    peer withdraw 111.0.0.1/32 and network 111.0.0.1/32 in 50ms
    received route：111.0.0.1/32 111.0.0.02/32
    ref_count:1

    step3:
    peer withdraw 111.0.0.1/32
    received route：111.0.0.02/32
    ref_count:0
    aggregate route will be withdrawn abnormally

Signed-off-by: liuze03 <liuze03@baidu.com>
(cherry picked from commit 704e189e594418571463c80a3efcc2c1020adcf4)
---

diff --git a/bgpd/bgp_route.c b/bgpd/bgp_route.c
index 35223f5569..29e2768d17 100644
--- a/bgpd/bgp_route.c
+++ b/bgpd/bgp_route.c
@@ -4233,6 +4233,12 @@ int bgp_update(struct peer *peer, const struct prefix *p, uint32_t addpath_id,
 			 * need to be imported again, so flag accordingly.
 			 */
 			force_evpn_import = true;
+		} else {
+			/* implicit withdraw, decrement aggregate and pcount
+			 * here. only if update is accepted, they'll increment
+			 * below.
+			 */
+			bgp_aggregate_decrement(bgp, p, pi, afi, safi);
 		}
 
 		/* Received Logging. */
@@ -4253,11 +4259,6 @@ int bgp_update(struct peer *peer, const struct prefix *p, uint32_t addpath_id,
 		/* The attribute is changed. */
 		bgp_path_info_set_flag(dest, pi, BGP_PATH_ATTR_CHANGED);
 
-		/* implicit withdraw, decrement aggregate and pcount here.
-		 * only if update is accepted, they'll increment below.
-		 */
-		bgp_aggregate_decrement(bgp, p, pi, afi, safi);
-
 		/* Update bgp route dampening information.  */
 		if (CHECK_FLAG(bgp->af_flags[afi][safi], BGP_CONFIG_DAMPENING)
 		    && peer->sort == BGP_PEER_EBGP) {