bridge: Allow deleting FDB entries with non-existent VLAN

It is currently impossible to delete individual FDB entries (as opposed
to flushing) that were added with a VLAN that no longer exists:

 # ip link add name dummy1 up type dummy
 # ip link add name br1 up type bridge vlan_filtering 1
 # ip link set dev dummy1 master br1
 # bridge fdb add 00:11:22:33:44:55 dev dummy1 master static vlan 1
 # bridge vlan del vid 1 dev dummy1
 # bridge fdb get 00:11:22:33:44:55 br br1 vlan 1
 00:11:22:33:44:55 dev dummy1 vlan 1 master br1 static
 # bridge fdb del 00:11:22:33:44:55 dev dummy1 master vlan 1
 RTNETLINK answers: Invalid argument
 # bridge fdb get 00:11:22:33:44:55 br br1 vlan 1
 00:11:22:33:44:55 dev dummy1 vlan 1 master br1 static

This is in contrast to MDB entries that can be deleted after the VLAN
was deleted:

 # bridge vlan add vid 10 dev dummy1
 # bridge mdb add dev br1 port dummy1 grp 239.1.1.1 permanent vid 10
 # bridge vlan del vid 10 dev dummy1
 # bridge mdb get dev br1 grp 239.1.1.1 vid 10
 dev br1 port dummy1 grp 239.1.1.1 permanent vid 10
 # bridge mdb del dev br1 port dummy1 grp 239.1.1.1 permanent vid 10
 # bridge mdb get dev br1 grp 239.1.1.1 vid 10
 Error: bridge: MDB entry not found.

Align the two interfaces and allow user space to delete FDB entries that
were added with a VLAN that no longer exists:

 # ip link add name dummy1 up type dummy
 # ip link add name br1 up type bridge vlan_filtering 1
 # ip link set dev dummy1 master br1
 # bridge fdb add 00:11:22:33:44:55 dev dummy1 master static vlan 1
 # bridge vlan del vid 1 dev dummy1
 # bridge fdb get 00:11:22:33:44:55 br br1 vlan 1
 00:11:22:33:44:55 dev dummy1 vlan 1 master br1 static
 # bridge fdb del 00:11:22:33:44:55 dev dummy1 master vlan 1
 # bridge fdb get 00:11:22:33:44:55 br br1 vlan 1
 Error: Fdb entry not found.

Add a selftest to make sure this behavior does not regress:

 # ./rtnetlink.sh -t kci_test_fdb_del
 PASS: bridge fdb del

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Andy Roulin <aroulin@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://patch.msgid.link/20241105133954.350479-1-idosch@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
index 1cd7bade9b3ba30b6be40f1ccad155ffc5cdb137..77f110035df15d3a6430d808faa212be80808ddc 100644 (file)
--- a/net/bridge/br_fdb.c
+++ b/net/bridge/br_fdb.c
@@ -1319,7 +1319,6 @@ int br_fdb_delete(struct ndmsg *ndm, struct nlattr *tb[],
 {
        struct net_bridge_vlan_group *vg;
        struct net_bridge_port *p = NULL;
-       struct net_bridge_vlan *v;
        struct net_bridge *br;
        int err;
 
@@ -1338,14 +1337,10 @@ int br_fdb_delete(struct ndmsg *ndm, struct nlattr *tb[],
        }
 
        if (vid) {
-               v = br_vlan_find(vg, vid);
-               if (!v) {
-                       pr_info("bridge: RTM_DELNEIGH with unconfigured vlan %d on %s\n", vid, dev->name);
-                       return -EINVAL;
-               }
-
                err = __br_fdb_delete(br, p, addr, vid);
        } else {
+               struct net_bridge_vlan *v;
+
                err = -ENOENT;
                err &= __br_fdb_delete(br, p, addr, 0);
                if (!vg || !vg->num_vlans)

diff --git a/tools/testing/selftests/net/rtnetlink.sh b/tools/testing/selftests/net/rtnetlink.sh
index 87dce3efe31e4a9179ef40a710bf69fddc1b50a0..6e216d7a8e2f0ee5f177872b2c14dba83b826c9c 100755 (executable)
--- a/tools/testing/selftests/net/rtnetlink.sh
+++ b/tools/testing/selftests/net/rtnetlink.sh
@@ -25,6 +25,7 @@ ALL_TESTS="
        kci_test_ipsec
        kci_test_ipsec_offload
        kci_test_fdb_get
+       kci_test_fdb_del
        kci_test_neigh_get
        kci_test_bridge_parent_id
        kci_test_address_proto
@@ -1065,6 +1066,45 @@ kci_test_fdb_get()
        end_test "PASS: bridge fdb get"
 }
 
+kci_test_fdb_del()
+{
+       local test_mac=de:ad:be:ef:13:37
+       local dummydev="dummy1"
+       local brdev="test-br0"
+       local ret=0
+
+       run_cmd_grep 'bridge fdb get' bridge fdb help
+       if [ $? -ne 0 ]; then
+               end_test "SKIP: fdb del tests: iproute2 too old"
+               return $ksft_skip
+       fi
+
+       setup_ns testns
+       if [ $? -ne 0 ]; then
+               end_test "SKIP fdb del tests: cannot add net namespace $testns"
+               return $ksft_skip
+       fi
+       IP="ip -netns $testns"
+       BRIDGE="bridge -netns $testns"
+       run_cmd $IP link add $dummydev type dummy
+       run_cmd $IP link add name $brdev type bridge vlan_filtering 1
+       run_cmd $IP link set dev $dummydev master $brdev
+       run_cmd $BRIDGE fdb add $test_mac dev $dummydev master static vlan 1
+       run_cmd $BRIDGE vlan del vid 1 dev $dummydev
+       run_cmd $BRIDGE fdb get $test_mac br $brdev vlan 1
+       run_cmd $BRIDGE fdb del $test_mac dev $dummydev master vlan 1
+       run_cmd_fail $BRIDGE fdb get $test_mac br $brdev vlan 1
+
+       ip netns del $testns &>/dev/null
+
+       if [ $ret -ne 0 ]; then
+               end_test "FAIL: bridge fdb del"
+               return 1
+       fi
+
+       end_test "PASS: bridge fdb del"
+}
+
 kci_test_neigh_get()
 {
        dstmac=de:ad:be:ef:13:37