selftests: mptcp: join: check re-using ID of closed subflow

This test extends "delete and re-add" to validate the previous commit. A
new 'subflow' endpoint is added, but the subflow request will be
rejected. The result is that no subflow will be established from this
address.

Later, the endpoint is removed and re-added after having cleared the
firewall rule. Before the previous commit, the client would not have
been able to create this new subflow.

While at it, extra checks have been added to validate the expected
numbers of MPJ and RM_ADDR.

The 'Fixes' tag here below is the same as the one from the previous
commit: this patch here is not fixing anything wrong in the selftests,
but it validates the previous fix for an issue introduced by this commit
ID.

Fixes: b6c08380860b ("mptcp: remove addr and subflow in PM netlink")
Cc: stable@vger.kernel.org
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20240819-net-mptcp-pm-reusing-id-v1-4-38035d40de5b@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/tools/testing/selftests/net/mptcp/mptcp_join.sh b/tools/testing/selftests/net/mptcp/mptcp_join.sh
index 25077ccf31d275c701cf2f0fa7dfdfd48d389595..fbb0174145ad32bfad98b93fc4d5e85adf4116e1 100755 (executable)
--- a/tools/testing/selftests/net/mptcp/mptcp_join.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_join.sh
@@ -436,9 +436,10 @@ reset_with_tcp_filter()
        local ns="${!1}"
        local src="${2}"
        local target="${3}"
+       local chain="${4:-INPUT}"
 
        if ! ip netns exec "${ns}" ${iptables} \
-                       -A INPUT \
+                       -A "${chain}" \
                        -s "${src}" \
                        -p tcp \
                        -j "${target}"; then
@@ -3571,10 +3572,10 @@ endpoint_tests()
                mptcp_lib_kill_wait $tests_pid
        fi
 
-       if reset "delete and re-add" &&
+       if reset_with_tcp_filter "delete and re-add" ns2 10.0.3.2 REJECT OUTPUT &&
           mptcp_lib_kallsyms_has "subflow_rebuild_header$"; then
-               pm_nl_set_limits $ns1 1 1
-               pm_nl_set_limits $ns2 1 1
+               pm_nl_set_limits $ns1 0 2
+               pm_nl_set_limits $ns2 0 2
                pm_nl_add_endpoint $ns2 10.0.2.2 id 2 dev ns2eth2 flags subflow
                test_linkfail=4 speed=20 \
                        run_tests $ns1 $ns2 10.0.1.1 &
@@ -3591,11 +3592,27 @@ endpoint_tests()
                chk_subflow_nr "after delete" 1
                chk_mptcp_info subflows 0 subflows 0
 
-               pm_nl_add_endpoint $ns2 10.0.2.2 dev ns2eth2 flags subflow
+               pm_nl_add_endpoint $ns2 10.0.2.2 id 2 dev ns2eth2 flags subflow
                wait_mpj $ns2
                chk_subflow_nr "after re-add" 2
                chk_mptcp_info subflows 1 subflows 1
+
+               pm_nl_add_endpoint $ns2 10.0.3.2 id 3 flags subflow
+               wait_attempt_fail $ns2
+               chk_subflow_nr "after new reject" 2
+               chk_mptcp_info subflows 1 subflows 1
+
+               ip netns exec "${ns2}" ${iptables} -D OUTPUT -s "10.0.3.2" -p tcp -j REJECT
+               pm_nl_del_endpoint $ns2 3 10.0.3.2
+               pm_nl_add_endpoint $ns2 10.0.3.2 id 3 flags subflow
+               wait_mpj $ns2
+               chk_subflow_nr "after no reject" 3
+               chk_mptcp_info subflows 2 subflows 2
+
                mptcp_lib_kill_wait $tests_pid
+
+               chk_join_nr 3 3 3
+               chk_rm_nr 1 1
        fi
 
        # remove and re-add