On 24/11/2022 23:09, Ido Schimmel wrote:

When the kernel receives a route deletion request from user space it tries to delete a route that matches the route attributes specified in the request.

If only prefix information is specified in the request, the kernel should delete the first matching FIB alias regardless of its associated FIB info. However, an error is currently returned when the FIB info is backed by a nexthop object:

# ip nexthop add id 1 via 192.0.2.2 dev dummy10 # ip route add 198.51.100.0/24 nhid 1 # ip route del 198.51.100.0/24 RTNETLINK answers: No such process

Fix by matching on such a FIB info when legacy nexthop attributes are not specified in the request. An earlier check already covers the case where a nexthop ID is specified in the request.

Add tests that cover these flows. Before the fix:

# ./fib_nexthops.sh -t ipv4_fcnal ... TEST: Delete route when not specifying nexthop attributes [FAIL]

Tests passed: 11 Tests failed: 1

After the fix:

# ./fib_nexthops.sh -t ipv4_fcnal ... TEST: Delete route when not specifying nexthop attributes [ OK ]

Tests passed: 12 Tests failed: 0

No regressions in other tests:

# ./fib_nexthops.sh ... Tests passed: 228 Tests failed: 0

# ./fib_tests.sh ... Tests passed: 186 Tests failed: 0

Cc: stable@vger.kernel.org Reported-by: Jonas Gorski jonas.gorski@gmail.com Tested-by: Jonas Gorski jonas.gorski@gmail.com Fixes: 493ced1ac47c ("ipv4: Allow routes to use nexthop objects") Fixes: 6bf92d70e690 ("net: ipv4: fix route with nexthop object delete warning") Fixes: 61b91eb33a69 ("ipv4: Handle attempt to delete multipath route when fib_info contains an nh reference") Signed-off-by: Ido Schimmel idosch@nvidia.com

---

net/ipv4/fib_semantics.c | 8 +++++--- tools/testing/selftests/net/fib_nexthops.sh | 11 +++++++++++ 2 files changed, 16 insertions(+), 3 deletions(-)

Reviewed-by: Nikolay Aleksandrov razor@blackwall.org

diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c index f721c308248b..19a662003eef 100644 --- a/net/ipv4/fib_semantics.c +++ b/net/ipv4/fib_semantics.c @@ -888,9 +888,11 @@ int fib_nh_match(struct net *net, struct fib_config *cfg, struct fib_info *fi, return 1; }

• /* cannot match on nexthop object attributes */
• if (fi->nh)

• return 1;
  

• if (fi->nh) {

• if (cfg->fc_oif || cfg->fc_gw_family || cfg->fc_mp)
  

• 	return 1;
  

• return 0;
  

• }

if (cfg->fc_oif || cfg->fc_gw_family) { struct fib_nh *nh; diff --git a/tools/testing/selftests/net/fib_nexthops.sh b/tools/testing/selftests/net/fib_nexthops.sh index ee5e98204d3d..a47b26ab48f2 100755 --- a/tools/testing/selftests/net/fib_nexthops.sh +++ b/tools/testing/selftests/net/fib_nexthops.sh @@ -1228,6 +1228,17 @@ ipv4_fcnal() run_cmd "$IP ro add 172.16.101.0/24 nhid 21" run_cmd "$IP ro del 172.16.101.0/24 nexthop via 172.16.1.7 dev veth1 nexthop via 172.16.1.8 dev veth1" log_test $? 2 "Delete multipath route with only nh id based entry"

• run_cmd "$IP nexthop add id 22 via 172.16.1.6 dev veth1"
• run_cmd "$IP ro add 172.16.102.0/24 nhid 22"
• run_cmd "$IP ro del 172.16.102.0/24 dev veth1"
• log_test $? 2 "Delete route when specifying only nexthop device"
• run_cmd "$IP ro del 172.16.102.0/24 via 172.16.1.6"
• log_test $? 2 "Delete route when specifying only gateway"
• run_cmd "$IP ro del 172.16.102.0/24"
• log_test $? 0 "Delete route when not specifying nexthop attributes"

} ipv4_grp_fcnal()