[PATCH 6.1.y] selftests: mptcp: join: check removing ID 0 endpoint

["Matthieu Baerts (NGI0)" <matttbe@kernel.org>]

commit 5f94b08c001290acda94d9d8868075590931c198 upstream.

Removing the endpoint linked to the initial subflow should trigger a
RM_ADDR for the right ID, and the removal of the subflow. That's what is
now being verified in the "delete and re-add" test.

Note that removing the initial subflow will not decrement the 'subflows'
counters, which corresponds to the *additional* subflows. On the other
hand, when the same endpoint is re-added, it will increment this
counter, as it will be seen as an additional subflow this time.

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: 3ad14f54bd74 ("mptcp: more accurate MPC endpoint tracking")
Cc: stable@vger.kernel.org
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
[ Conflicts in mptcp_join.sh, because the helpers are different in this
  version:
  - run_tests has been modified a few times to reduce the number of
    positional parameters
  - no chk_mptcp_info helper
  - chk_subflow_nr taking an extra parameter
  - kill_tests_wait instead of mptcp_lib_kill_wait ]
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
 .../testing/selftests/net/mptcp/mptcp_join.sh | 21 +++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/net/mptcp/mptcp_join.sh b/tools/testing/selftests/net/mptcp/mptcp_join.sh
index 7682a7e2cb51..ea1c7992336d 100755
--- a/tools/testing/selftests/net/mptcp/mptcp_join.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_join.sh
@@ -3268,19 +3268,20 @@ endpoint_tests()
 
 	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 0 2
-		pm_nl_set_limits $ns2 0 2
+		pm_nl_set_limits $ns1 0 3
+		pm_nl_set_limits $ns2 0 3
+		pm_nl_add_endpoint $ns2 10.0.1.2 id 1 dev ns2eth1 flags subflow
 		pm_nl_add_endpoint $ns2 10.0.2.2 id 2 dev ns2eth2 flags subflow
 		run_tests $ns1 $ns2 10.0.1.1 4 0 0 speed_20 2>/dev/null &
 
 		wait_mpj $ns2
 		pm_nl_del_endpoint $ns2 2 10.0.2.2
 		sleep 0.5
-		chk_subflow_nr needtitle "after delete" 1
+		chk_subflow_nr needtitle "after delete id 2" 1
 
 		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_subflow_nr "" "after re-add id 2" 2
 
 		pm_nl_add_endpoint $ns2 10.0.3.2 id 3 flags subflow
 		wait_attempt_fail $ns2
@@ -3292,10 +3293,18 @@ endpoint_tests()
 		wait_mpj $ns2
 		chk_subflow_nr "" "after no reject" 3
 
+		pm_nl_del_endpoint $ns2 1 10.0.1.2
+		sleep 0.5
+		chk_subflow_nr "" "after delete id 0" 2
+
+		pm_nl_add_endpoint $ns2 10.0.1.2 id 1 dev ns2eth1 flags subflow
+		wait_mpj $ns2
+		chk_subflow_nr "" "after re-add id 0" 3
+
 		kill_tests_wait
 
-		chk_join_nr 3 3 3
-		chk_rm_nr 1 1
+		chk_join_nr 4 4 4
+		chk_rm_nr 2 2
 	fi
 
 	# remove and re-add
-- 
2.45.2