[PATCH mptcp-net v7 2/2] selftests: mptcp: join: re-add the initial subflow endp with fullmesh

[Abdul Wasey <w453y.me@gmail.com>]

The "delete and re-add" test validates the removal and the re-addition
of the endpoint used by the initial subflow, but without the fullmesh
flag.

Do the same with the fullmesh flag: with a second subflow, after a reset
of the initial subflow, and with the initial subflow only, then re-adding
its endpoint or adding another one. Without the previous patch, no new
subflow is created, except when adding another endpoint.

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: 045e9d812868 ("mptcp: fix duplicate subflow creation")
Cc: stable@vger.kernel.org
Signed-off-by: Abdul Wasey <w453y.me@gmail.com>
---
 .../testing/selftests/net/mptcp/mptcp_join.sh | 129 ++++++++++++++++++
 1 file changed, 129 insertions(+)

diff --git a/tools/testing/selftests/net/mptcp/mptcp_join.sh b/tools/testing/selftests/net/mptcp/mptcp_join.sh
index 18ce7136a..4cb3a546b 100755
--- a/tools/testing/selftests/net/mptcp/mptcp_join.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_join.sh
@@ -4445,6 +4445,135 @@ endpoint_tests()
 		chk_rm_nr 4 4
 	fi
 
+	# remove and re-add the endpoint of the initial subflow, with fullmesh
+	if reset_with_events "delete and re-add, fullmesh" &&
+	   continue_if mptcp_lib_kallsyms_has "subflow_rebuild_header$"; then
+		pm_nl_set_limits $ns1 0 2
+		pm_nl_set_limits $ns2 0 2
+		pm_nl_add_endpoint $ns2 10.0.1.2 id 1 dev ns2eth1 flags subflow,fullmesh
+		pm_nl_add_endpoint $ns2 10.0.2.2 id 2 dev ns2eth2 flags subflow,fullmesh
+		{ timeout_test=120 test_linkfail=128 speed=5 \
+			run_tests $ns1 $ns2 10.0.1.1 & } 2>/dev/null
+		local tests_pid=$!
+
+		wait_event ns2 MPTCP_LIB_EVENT_ESTABLISHED 1
+		wait_mpj 1
+		chk_subflow_nr "before delete id 0" 2
+
+		pm_nl_del_endpoint $ns2 1 10.0.1.2
+		sleep 0.5
+		chk_subflow_nr "after delete id 0" 1
+
+		pm_nl_add_endpoint $ns2 10.0.1.2 id 1 dev ns2eth1 flags subflow,fullmesh
+		wait_mpj 2
+		chk_subflow_nr "after re-add id 0" 2
+
+		mptcp_lib_kill_group_wait $tests_pid
+		kill_events_pids
+
+		chk_join_nr 2 2 2
+		chk_rm_nr 1 1
+	fi
+
+	# same, but the initial subflow is reset before removing its endpoint
+	if reset_with_events "delete and re-add, fullmesh, after reset" &&
+	   continue_if mptcp_lib_kallsyms_has "subflow_rebuild_header$"; then
+		pm_nl_set_limits $ns1 0 2
+		pm_nl_set_limits $ns2 0 2
+		pm_nl_add_endpoint $ns2 10.0.1.2 id 1 dev ns2eth1 flags subflow,fullmesh
+		pm_nl_add_endpoint $ns2 10.0.2.2 id 2 dev ns2eth2 flags subflow,fullmesh
+		{ timeout_test=120 test_linkfail=128 speed=5 \
+			run_tests $ns1 $ns2 10.0.1.1 & } 2>/dev/null
+		local tests_pid=$!
+
+		wait_event ns2 MPTCP_LIB_EVENT_ESTABLISHED 1
+		wait_mpj 1
+		chk_subflow_nr "before reset" 2
+
+		if ip netns exec "${ns1}" ${iptables} -A INPUT -s "10.0.1.2" \
+		      -p tcp --tcp-option 30 -j REJECT --reject-with tcp-reset; then
+			wait_event ns2 MPTCP_LIB_EVENT_SUB_CLOSED 1
+			ip netns exec "${ns1}" ${iptables} -F INPUT
+			chk_evt_nr ns2 MPTCP_LIB_EVENT_SUB_CLOSED 1 error 1
+
+			pm_nl_del_endpoint $ns2 1 10.0.1.2
+			pm_nl_add_endpoint $ns2 10.0.1.2 id 1 dev ns2eth1 flags subflow,fullmesh
+			wait_mpj 2
+			chk_mptcp_info subflows 2 subflows 2
+			chk_join_nr 2 2 2
+		else
+			mark_as_skipped "unable to set the filter rules"
+		fi
+
+		mptcp_lib_kill_group_wait $tests_pid
+		kill_events_pids
+	fi
+
+	# only the initial subflow: once its endpoint is removed, no live subflow
+	# is left to take the remote address from
+	if reset_with_events "delete and re-add, fullmesh, single subflow" &&
+	   continue_if mptcp_lib_kallsyms_has "subflow_rebuild_header$"; then
+		pm_nl_set_limits $ns1 0 2
+		pm_nl_set_limits $ns2 0 2
+		pm_nl_add_endpoint $ns2 10.0.1.2 id 1 dev ns2eth1 flags subflow,fullmesh
+		{ timeout_test=120 test_linkfail=128 speed=5 \
+			run_tests $ns1 $ns2 10.0.1.1 & } 2>/dev/null
+		local tests_pid=$!
+
+		wait_event ns2 MPTCP_LIB_EVENT_ESTABLISHED 1
+		# the PM worker accounts the initial subflow endpoint after the
+		# ESTABLISHED event, in the same run where it creates the subflows:
+		# a join on another endpoint shows it is done, then remove it
+		pm_nl_add_endpoint $ns2 10.0.3.2 id 3 dev ns2eth3 flags subflow
+		wait_mpj 1
+		pm_nl_del_endpoint $ns2 3 10.0.3.2
+		wait_event ns2 MPTCP_LIB_EVENT_SUB_CLOSED 1
+		pm_nl_del_endpoint $ns2 1 10.0.1.2
+		wait_event ns2 MPTCP_LIB_EVENT_SUB_CLOSED 2
+		sleep 0.5
+		chk_subflow_nr "after delete" 0
+		pm_nl_add_endpoint $ns2 10.0.1.2 id 1 dev ns2eth1 flags subflow,fullmesh
+		wait_mpj 2
+		chk_mptcp_info subflows 1 subflows 1
+
+		mptcp_lib_kill_group_wait $tests_pid
+		kill_events_pids
+
+		chk_join_nr 2 2 2
+	fi
+
+	# same, but another endpoint is added after the removal
+	if reset_with_events "delete and add another, fullmesh, single subflow" &&
+	   continue_if mptcp_lib_kallsyms_has "subflow_rebuild_header$"; then
+		pm_nl_set_limits $ns1 0 2
+		pm_nl_set_limits $ns2 0 2
+		pm_nl_add_endpoint $ns2 10.0.1.2 id 1 dev ns2eth1 flags subflow,fullmesh
+		{ timeout_test=120 test_linkfail=128 speed=5 \
+			run_tests $ns1 $ns2 10.0.1.1 & } 2>/dev/null
+		local tests_pid=$!
+
+		wait_event ns2 MPTCP_LIB_EVENT_ESTABLISHED 1
+		# the PM worker accounts the initial subflow endpoint after the
+		# ESTABLISHED event, in the same run where it creates the subflows:
+		# a join on another endpoint shows it is done, then remove it
+		pm_nl_add_endpoint $ns2 10.0.3.2 id 3 dev ns2eth3 flags subflow
+		wait_mpj 1
+		pm_nl_del_endpoint $ns2 3 10.0.3.2
+		wait_event ns2 MPTCP_LIB_EVENT_SUB_CLOSED 1
+		pm_nl_del_endpoint $ns2 1 10.0.1.2
+		wait_event ns2 MPTCP_LIB_EVENT_SUB_CLOSED 2
+		sleep 0.5
+		chk_subflow_nr "after delete" 0
+		pm_nl_add_endpoint $ns2 10.0.2.2 id 2 dev ns2eth2 flags subflow,fullmesh
+		wait_mpj 2
+		chk_mptcp_info subflows 1 subflows 1
+
+		mptcp_lib_kill_group_wait $tests_pid
+		kill_events_pids
+
+		chk_join_nr 2 2 2
+	fi
+
 	# remove and re-add
 	if reset_with_events "delete re-add signal" &&
 	   continue_if mptcp_lib_kallsyms_has "subflow_rebuild_header$"; then
-- 
2.43.0