Merge branch 'mptcp-handle-late-add_addr-selftests-skip'

Matthieu Baerts says:

====================
mptcp: handle late ADD_ADDR + selftests skip

Here are a few independent fixes related to MPTCP and its selftests:

- Patch 1: correctly handle ADD_ADDR being received after the switch to
  'fully-established'. A fix for another recent fix backported up to
  v5.14.

- Patches 2-5: properly mark some MPTCP Join subtests as 'skipped' if
  the tested kernel doesn't support the feature being validated. Some
  fixes for up to v5.13, v5.18, v6.11 and v6.18-rc1 respectively.
====================

Link: https://patch.msgid.link/20251020-net-mptcp-c-flag-late-add-addr-v1-0-8207030cb0e8@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

2 files changed, 15 insertions, 9 deletions

diff --git a/net/mptcp/pm_kernel.c b/net/mptcp/pm_kernel.c
index e0f44dc232aa..2ae95476dba3 100644
--- a/net/mptcp/pm_kernel.c
+++ b/net/mptcp/pm_kernel.c
@@ -370,6 +370,10 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
 	}
 
 subflow:
+	/* No need to try establishing subflows to remote id0 if not allowed */
+	if (mptcp_pm_add_addr_c_flag_case(msk))
+		goto exit;
+
 	/* check if should create a new subflow */
 	while (msk->pm.local_addr_used < endp_subflow_max &&
 	       msk->pm.extra_subflows < limit_extra_subflows) {
@@ -401,6 +405,8 @@ subflow:
 			__mptcp_subflow_connect(sk, &local, &addrs[i]);
 		spin_lock_bh(&msk->pm.lock);
 	}
+
+exit:
 	mptcp_pm_nl_check_work_pending(msk);
 }
 
diff --git a/tools/testing/selftests/net/mptcp/mptcp_join.sh b/tools/testing/selftests/net/mptcp/mptcp_join.sh
index c90d8e8b95cb..78a1aa4ecff2 100755
--- a/tools/testing/selftests/net/mptcp/mptcp_join.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_join.sh
@@ -2324,7 +2324,7 @@ laminar_endp_tests()
 {
 	# no laminar endpoints: routing rules are used
 	if reset_with_tcp_filter "without a laminar endpoint" ns1 10.0.2.2 REJECT &&
-	   mptcp_lib_kallsyms_has "mptcp_pm_get_endp_laminar_max$"; then
+	   continue_if mptcp_lib_kallsyms_has "mptcp_pm_get_endp_laminar_max$"; then
 		pm_nl_set_limits $ns1 0 2
 		pm_nl_set_limits $ns2 2 2
 		pm_nl_add_endpoint $ns1 10.0.2.1 flags signal
@@ -2336,7 +2336,7 @@ laminar_endp_tests()
 
 	# laminar endpoints: this endpoint is used
 	if reset_with_tcp_filter "with a laminar endpoint" ns1 10.0.2.2 REJECT &&
-	   mptcp_lib_kallsyms_has "mptcp_pm_get_endp_laminar_max$"; then
+	   continue_if mptcp_lib_kallsyms_has "mptcp_pm_get_endp_laminar_max$"; then
 		pm_nl_set_limits $ns1 0 2
 		pm_nl_set_limits $ns2 2 2
 		pm_nl_add_endpoint $ns1 10.0.2.1 flags signal
@@ -2348,7 +2348,7 @@ laminar_endp_tests()
 
 	# laminar endpoints: these endpoints are used
 	if reset_with_tcp_filter "with multiple laminar endpoints" ns1 10.0.2.2 REJECT &&
-	   mptcp_lib_kallsyms_has "mptcp_pm_get_endp_laminar_max$"; then
+	   continue_if mptcp_lib_kallsyms_has "mptcp_pm_get_endp_laminar_max$"; then
 		pm_nl_set_limits $ns1 0 2
 		pm_nl_set_limits $ns2 2 2
 		pm_nl_add_endpoint $ns1 10.0.2.1 flags signal
@@ -2363,7 +2363,7 @@ laminar_endp_tests()
 
 	# laminar endpoints: only one endpoint is used
 	if reset_with_tcp_filter "single laminar endpoint" ns1 10.0.2.2 REJECT &&
-	   mptcp_lib_kallsyms_has "mptcp_pm_get_endp_laminar_max$"; then
+	   continue_if mptcp_lib_kallsyms_has "mptcp_pm_get_endp_laminar_max$"; then
 		pm_nl_set_limits $ns1 0 2
 		pm_nl_set_limits $ns2 2 2
 		pm_nl_add_endpoint $ns1 10.0.2.1 flags signal
@@ -2376,7 +2376,7 @@ laminar_endp_tests()
 
 	# laminar endpoints: subflow and laminar flags
 	if reset_with_tcp_filter "sublow + laminar endpoints" ns1 10.0.2.2 REJECT &&
-	   mptcp_lib_kallsyms_has "mptcp_pm_get_endp_laminar_max$"; then
+	   continue_if mptcp_lib_kallsyms_has "mptcp_pm_get_endp_laminar_max$"; then
 		pm_nl_set_limits $ns1 0 4
 		pm_nl_set_limits $ns2 2 4
 		pm_nl_add_endpoint $ns1 10.0.2.1 flags signal
@@ -3939,7 +3939,7 @@ endpoint_tests()
 	# subflow_rebuild_header is needed to support the implicit flag
 	# userspace pm type prevents add_addr
 	if reset "implicit EP" &&
-	   mptcp_lib_kallsyms_has "subflow_rebuild_header$"; then
+	   continue_if mptcp_lib_kallsyms_has "subflow_rebuild_header$"; then
 		pm_nl_set_limits $ns1 2 2
 		pm_nl_set_limits $ns2 2 2
 		pm_nl_add_endpoint $ns1 10.0.2.1 flags signal
@@ -3964,7 +3964,7 @@ endpoint_tests()
 	fi
 
 	if reset_with_tcp_filter "delete and re-add" ns2 10.0.3.2 REJECT OUTPUT &&
-	   mptcp_lib_kallsyms_has "subflow_rebuild_header$"; then
+	   continue_if mptcp_lib_kallsyms_has "subflow_rebuild_header$"; then
 		start_events
 		pm_nl_set_limits $ns1 0 3
 		pm_nl_set_limits $ns2 0 3
@@ -4040,7 +4040,7 @@ endpoint_tests()
 
 	# remove and re-add
 	if reset_with_events "delete re-add signal" &&
-	   mptcp_lib_kallsyms_has "subflow_rebuild_header$"; then
+	   continue_if mptcp_lib_kallsyms_has "subflow_rebuild_header$"; then
 		ip netns exec $ns1 sysctl -q net.mptcp.add_addr_timeout=0
 		pm_nl_set_limits $ns1 0 3
 		pm_nl_set_limits $ns2 3 3
@@ -4115,7 +4115,7 @@ endpoint_tests()
 
 	# flush and re-add
 	if reset_with_tcp_filter "flush re-add" ns2 10.0.3.2 REJECT OUTPUT &&
-	   mptcp_lib_kallsyms_has "subflow_rebuild_header$"; then
+	   continue_if mptcp_lib_kallsyms_has "subflow_rebuild_header$"; then
 		pm_nl_set_limits $ns1 0 2
 		pm_nl_set_limits $ns2 1 2
 		# broadcast IP: no packet for this address will be received on ns1