From 31fc89b2301ca624a331539c0a077627bacddbe2 Mon Sep 17 00:00:00 2001 From: Louis Scalbert Date: Fri, 17 May 2024 17:57:46 +0200 Subject: [PATCH] bgpd, tests: fix route leaking from the default l3vrf Leaked route from the l3VRF are installed with the loopback as the nexthop interface instead of the real interface. > B>* 10.0.0.0/30 [20/0] is directly connected, lo (vrf default), weight 1, 00:21:01 Routing of packet from a L3VRF to the default L3VRF destined to a leak prefix fails because of the default routing rules on Linux. > 0: from all lookup local > 1000: from all lookup [l3mdev-table] > 32766: from all lookup main > 32767: from all lookup default When the packet is received in the loopback interface, the local rules are checked without match, then the l3mdev-table says to route to the loopback. A routing loop occurs (TTL is decreasing). > 12:26:27.928748 ens37 In IP (tos 0x0, ttl 64, id 26402, offset 0, flags [DF], proto ICMP (1), length 84) > 10.0.0.2 > 10.0.1.2: ICMP echo request, id 47463, seq 1, length 64 > 12:26:27.928784 red Out IP (tos 0x0, ttl 63, id 26402, offset 0, flags [DF], proto ICMP (1), length 84) > 10.0.0.2 > 10.0.1.2: ICMP echo request, id 47463, seq 1, length 64 > 12:26:27.928797 ens38 Out IP (tos 0x0, ttl 63, id 26402, offset 0, flags [DF], proto ICMP (1), length 84) > 10.0.0.2 > 10.0.1.2: ICMP echo request, id 47463, seq 1, length 64 Do not set the lo interface as a nexthop interface. Keep the real interface where possible. Fixes: db7cf73a33 ("bgpd: fix interface on leaks from redistribute connected") Fixes: 067fbab4e4 ("bgpd: fix interface on leaks from network statement") Fixes: 8a02d9fe1e ("bgpd: Set nh ifindex to VRF's interface, not the real") Fixes: https://github.com/FRRouting/frr/issues/15909 Signed-off-by: Louis Scalbert --- bgpd/bgp_mplsvpn.c | 5 +++-- .../test_bgp-vrf-route-leak-basic.py | 2 +- .../ospf_multi_vrf_bgp_route_leak/r2/zebra-vrf-ray.txt | 4 ++-- 3 files changed, 6 insertions(+), 5 deletions(-) diff --git a/bgpd/bgp_mplsvpn.c b/bgpd/bgp_mplsvpn.c index d17fdc7169..39f8f84a02 100644 --- a/bgpd/bgp_mplsvpn.c +++ b/bgpd/bgp_mplsvpn.c @@ -2240,8 +2240,9 @@ static void vpn_leak_to_vrf_update_onevrf(struct bgp *to_bgp, /* to */ * Let the kernel to decide with double lookup the real next-hop * interface when installing the route. */ - if (src_bgp || bpi_ultimate->sub_type == BGP_ROUTE_STATIC || - bpi_ultimate->sub_type == BGP_ROUTE_REDISTRIBUTE) { + if (src_vrf->vrf_id != VRF_DEFAULT && + (src_bgp || bpi_ultimate->sub_type == BGP_ROUTE_STATIC || + bpi_ultimate->sub_type == BGP_ROUTE_REDISTRIBUTE)) { ifp = if_get_vrf_loopback(src_vrf->vrf_id); if (ifp) static_attr.nh_ifindex = ifp->ifindex; diff --git a/tests/topotests/bgp_vrf_route_leak_basic/test_bgp-vrf-route-leak-basic.py b/tests/topotests/bgp_vrf_route_leak_basic/test_bgp-vrf-route-leak-basic.py index 013ddfece9..3938a966ee 100644 --- a/tests/topotests/bgp_vrf_route_leak_basic/test_bgp-vrf-route-leak-basic.py +++ b/tests/topotests/bgp_vrf_route_leak_basic/test_bgp-vrf-route-leak-basic.py @@ -116,7 +116,7 @@ def test_vrf_route_leak_donna(): "nexthops": [ { "fib": True, - "interfaceName": "lo", + "interfaceName": "dummy0", "vrf": "default", "active": True, }, diff --git a/tests/topotests/ospf_multi_vrf_bgp_route_leak/r2/zebra-vrf-ray.txt b/tests/topotests/ospf_multi_vrf_bgp_route_leak/r2/zebra-vrf-ray.txt index 6ab1bb8f92..1495c88936 100644 --- a/tests/topotests/ospf_multi_vrf_bgp_route_leak/r2/zebra-vrf-ray.txt +++ b/tests/topotests/ospf_multi_vrf_bgp_route_leak/r2/zebra-vrf-ray.txt @@ -1,9 +1,9 @@ VRF ray: B 10.0.1.0/24 [20/20] via 10.0.20.1, r2-eth1 (vrf default) inactive, weight 1, XX:XX:XX -B 10.0.2.0/24 [20/0] is directly connected, lo (vrf default) inactive, weight 1, XX:XX:XX +B 10.0.2.0/24 [20/0] is directly connected, r2-eth0 (vrf default) inactive, weight 1, XX:XX:XX B>* 10.0.3.0/24 [20/20] via 10.0.20.1, r2-eth1 (vrf default), weight 1, XX:XX:XX O>* 10.0.4.0/24 [110/20] via 10.0.40.4, r2-eth2, weight 1, XX:XX:XX -B 10.0.20.0/24 [20/0] is directly connected, lo (vrf default) inactive, weight 1, XX:XX:XX +B 10.0.20.0/24 [20/0] is directly connected, r2-eth1 (vrf default) inactive, weight 1, XX:XX:XX B>* 10.0.30.0/24 [20/20] via 10.0.20.1, r2-eth1 (vrf default), weight 1, XX:XX:XX O 10.0.40.0/24 [110/10] is directly connected, r2-eth2, weight 1, XX:XX:XX C>* 10.0.40.0/24 is directly connected, r2-eth2, XX:XX:XX -- 2.39.5