selftests: mptcp: explicitly trigger the listener diag code-path

The mptcp diag interface already experienced a few locking bugs
that lockdep and appropriate coverage have detected in advance.

Let's add a test-case triggering the relevant code path, to prevent
similar issues in the future.

Be careful to cope with very slow environments.

Note that we don't need an explicit timeout on the mptcp_connect
subprocess to cope with eventual bug/hang-up as the final cleanup
terminating the child processes will take care of that.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20240223-upstream-net-20240223-misc-fixes-v1-10-162e87e48497@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/tools/testing/selftests/net/mptcp/diag.sh b/tools/testing/selftests/net/mptcp/diag.sh
index 0a58ebb8b04c90e88b544e447620e6cc38df135e..f300f4e1eb59f89b1d3096f7a19821dc4be92402 100755 (executable)
--- a/tools/testing/selftests/net/mptcp/diag.sh
+++ b/tools/testing/selftests/net/mptcp/diag.sh
@@ -20,7 +20,7 @@ flush_pids()
 
        ip netns pids "${ns}" | xargs --no-run-if-empty kill -SIGUSR1 &>/dev/null
 
-       for _ in $(seq 10); do
+       for _ in $(seq $((timeout_poll * 10))); do
                [ -z "$(ip netns pids "${ns}")" ] && break
                sleep 0.1
        done
@@ -91,6 +91,15 @@ chk_msk_nr()
        __chk_msk_nr "grep -c token:" "$@"
 }
 
+chk_listener_nr()
+{
+       local expected=$1
+       local msg="$2"
+
+       __chk_nr "ss -inmlHMON $ns | wc -l" "$expected" "$msg - mptcp" 0
+       __chk_nr "ss -inmlHtON $ns | wc -l" "$expected" "$msg - subflows"
+}
+
 wait_msk_nr()
 {
        local condition="grep -c token:"
@@ -289,5 +298,24 @@ flush_pids
 chk_msk_inuse 0 "many->0"
 chk_msk_cestab 0 "many->0"
 
+chk_listener_nr 0 "no listener sockets"
+NR_SERVERS=100
+for I in $(seq 1 $NR_SERVERS); do
+       ip netns exec $ns ./mptcp_connect -p $((I + 20001)) \
+               -t ${timeout_poll} -l 0.0.0.0 >/dev/null 2>&1 &
+done
+
+for I in $(seq 1 $NR_SERVERS); do
+       mptcp_lib_wait_local_port_listen $ns $((I + 20001))
+done
+
+chk_listener_nr $NR_SERVERS "many listener sockets"
+
+# graceful termination
+for I in $(seq 1 $NR_SERVERS); do
+       echo a | ip netns exec $ns ./mptcp_connect -p $((I + 20001)) 127.0.0.1 >/dev/null 2>&1 &
+done
+flush_pids
+
 mptcp_lib_result_print_all_tap
 exit $ret