Multiple local fix (backport #20798)#20817
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donaldsharp merged 2 commits intostable/10.4from Feb 13, 2026
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Currently when a interface is seeing multiple link up events in a row,
we are seeing multiple local routes in the rib:
r9# show ip route vrf all nexthop-group
% 2026/02/08 23:18:00.371
Codes: K - kernel route, C - connected, L - local, S - static,
R - RIP, O - OSPF, I - IS-IS, B - BGP, E - EIGRP, N - NHRP,
T - Table, v - VNC, V - VNC-Direct, A - Babel, D - SHARP,
F - PBR, f - OpenFabric, t - Table-Direct,
> - selected route, * - FIB route, q - queued, r - rejected, b - backup
t - trapped, o - offload failure
IPv4 unicast VRF default:
C>* 11.1.5.0/30 (7) is directly connected, r9-eth0, weight 1, 00:01:52
L>* 11.1.5.2/32 (7) is directly connected, r9-eth0, weight 1, 00:01:52
B>* 50.1.1.7/32 [20/0] (10) via 11.1.5.1, r9-eth0, weight 1, 00:01:51
B>* 50.1.1.8/32 [20/0] (10) via 11.1.5.1, r9-eth0, weight 1, 00:01:51
L * 50.1.1.9/32 (17) is directly connected, r9-eth1, weight 1, 00:01:46
C * 50.1.1.9/32 (17) is directly connected, r9-eth1, weight 1, 00:01:46
L>* 50.1.1.9/32 (17) is directly connected, r9-eth1, weight 1, 00:01:46
B>* 50.1.1.10/32 [20/0] (10) via 11.1.5.1, r9-eth0, weight 1, 00:01:50
L * 198.10.1.1/32 (17) is directly connected, r9-eth1, weight 1, 00:01:46
C * 198.10.1.1/32 (17) is directly connected, r9-eth1, weight 1, 00:01:46
L>* 198.10.1.1/32 (17) is directly connected, r9-eth1, weight 1, 00:01:46
B 198.10.1.1/32 [20/0] (10) via 11.1.5.1, r9-eth0, weight 1, 00:01:46
Additionally FRR has made an improper choice about what route should also
be properly selected, because of this decision. The problem stems from
rib_compare_routes in zebra_rib.c already handling the multiple same
connected routes being passed for processing but not for local routes
to be considered the same. Modify the code to make local routes behave
the same here. This is the new result:
r9# show ip route vrf all nexthop-group
% 2026/02/08 23:18:00.371
Codes: K - kernel route, C - connected, L - local, S - static,
R - RIP, O - OSPF, I - IS-IS, B - BGP, E - EIGRP, N - NHRP,
T - Table, v - VNC, V - VNC-Direct, A - Babel, D - SHARP,
F - PBR, f - OpenFabric, t - Table-Direct,
> - selected route, * - FIB route, q - queued, r - rejected, b - backup
t - trapped, o - offload failure
IPv4 unicast VRF default:
C>* 11.1.5.0/30 (7) is directly connected, r9-eth0, weight 1, 00:01:52
L>* 11.1.5.2/32 (7) is directly connected, r9-eth0, weight 1, 00:01:52
B>* 50.1.1.7/32 [20/0] (10) via 11.1.5.1, r9-eth0, weight 1, 00:01:51
B>* 50.1.1.8/32 [20/0] (10) via 11.1.5.1, r9-eth0, weight 1, 00:01:51
C>* 50.1.1.9/32 (17) is directly connected, r9-eth1, weight 1, 00:01:46
L>* 50.1.1.9/32 (17) is directly connected, r9-eth1, weight 1, 00:01:46
B>* 50.1.1.10/32 [20/0] (10) via 11.1.5.1, r9-eth0, weight 1, 00:01:50
C>* 198.10.1.1/32 (17) is directly connected, r9-eth1, weight 1, 00:01:46
L>* 198.10.1.1/32 (17) is directly connected, r9-eth1, weight 1, 00:01:46
Fixes: #20337
Signed-off-by: Donald Sharp <sharpd@nvidia.com>
(cherry picked from commit bf1312b)
…local routes Show that the previous commit works properly and that when FRR receives a change for a interface that causes multiple event up scenarios, to treat the local routes as duplicate. Signed-off-by: Donald Sharp <sharpd@nvidia.com> (cherry picked from commit 23261aa)
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See first commit, but explicilty fix the problem where when receiving multiple link up events FRR is creating multpile local routes when it should not be.
This is an automatic backport of pull request #20798 done by Mergify.