[PATCH net-next v4] selftests/net/openvswitch: add SCTP flow key test

[Minxi Hou <houminxi@gmail.com>]

Add test_sctp_connect_v4() to verify OVS can match on SCTP flow keys
(sctp src/dst port).

The test sets up client and server namespaces connected through an
OVS bridge, installs port-keyed flows, and verifies:
  - sctp(dst=4443) matches client-to-server INIT
  - sctp(src=4443) matches server-to-client INIT-ACK
  - removing flows drops the connection
  - reinstalling flows restores connectivity

Signed-off-by: Minxi Hou <houminxi@gmail.com>
---
 .../selftests/net/openvswitch/openvswitch.sh  | 105 ++++++++++++++++++
 .../selftests/net/openvswitch/ovs-dpctl.py    |   5 +
 2 files changed, 110 insertions(+)

v3 -> v4: rebase onto latest net-next (2026-07-19), resolve test list
  conflict from merged trunc test

diff --git a/tools/testing/selftests/net/openvswitch/openvswitch.sh b/tools/testing/selftests/net/openvswitch/openvswitch.sh
index f75ee723415a..af9cf0888316 100755
--- a/tools/testing/selftests/net/openvswitch/openvswitch.sh
+++ b/tools/testing/selftests/net/openvswitch/openvswitch.sh
@@ -33,6 +33,7 @@ tests="
 	flow_set				flow-set: Flow modify
 	action_set				set: SET action rewrites fields
 	trunc					trunc: output truncation
+	sctp_connect_v4				sctp: SCTP flow key matching
 	psample					psample: Sampling packets with psample"
 
 info() {
@@ -530,6 +531,110 @@ test_trunc() {
 	return 0
 }
 
+# sctp_connect_v4 test
+# - sctp(dst=4443) matches client-to-server INIT
+# - sctp(src=4443) matches server-to-client INIT-ACK
+# - remove flows and verify connection fails, reinstall and recover
+test_sctp_connect_v4() {
+	local t="test_sctp_connect_v4"
+
+	which nc >/dev/null 2>&1 || return $ksft_skip
+	nc --sctp -z 127.0.0.1 1 </dev/null 2>/dev/null || return $ksft_skip
+	modprobe -q sctp 2>/dev/null || return $ksft_skip
+
+	sbx_add "$t" || return $?
+	ovs_add_dp "$t" sctp4 || return 1
+
+	info "create namespaces"
+	for ns in client server; do
+		ovs_add_netns_and_veths "$t" "sctp4" "$ns" \
+		    "${ns:0:1}0" "${ns:0:1}1" || return 1
+	done
+
+	ip netns exec client ip addr add 172.31.110.10/24 dev c1
+	ip netns exec client ip link set c1 up
+	ip netns exec server ip addr add 172.31.110.20/24 dev s1
+	ip netns exec server ip link set s1 up
+
+	# ARP forwarding
+	ovs_add_flow "$t" sctp4 \
+	    'in_port(1),eth(),eth_type(0x0806),arp()' \
+	    '2' || return 1
+	ovs_add_flow "$t" sctp4 \
+	    'in_port(2),eth(),eth_type(0x0806),arp()' \
+	    '1' || return 1
+
+	# SCTP port matching: dst for request, src for reply
+	ovs_add_flow "$t" sctp4 \
+	    'in_port(1),eth(),eth_type(0x0800),ipv4(proto=132),sctp(dst=4443)' \
+	    '2' || return 1
+	ovs_add_flow "$t" sctp4 \
+	    'in_port(2),eth(),eth_type(0x0800),ipv4(proto=132),sctp(src=4443)' \
+	    '1' || return 1
+
+	echo "server" | \
+		ovs_netns_spawn_daemon "$t" "server" \
+				nc --sctp -l 172.31.110.20 -vn 4443
+	local server_pid=$pid
+	ovs_wait ip netns exec server \
+	    ss -lnH sport = :4443 \| grep -q . \
+	    || return 1
+
+	info "verify SCTP association with port-keyed flows"
+	ovs_sbx "$t" ip netns exec client \
+	    nc --sctp -i 1 -zv 172.31.110.20 4443 \
+	    || return 1
+
+	ovs_del_flows "$t" sctp4
+
+	info "verify connection fails without flows"
+	ovs_add_flow "$t" sctp4 \
+	    'in_port(1),eth(),eth_type(0x0806),arp()' \
+	    '2' || return 1
+	ovs_add_flow "$t" sctp4 \
+	    'in_port(2),eth(),eth_type(0x0806),arp()' \
+	    '1' || return 1
+
+	kill -TERM $server_pid 2>/dev/null
+	wait $server_pid 2>/dev/null
+	echo "server2" | \
+		ovs_netns_spawn_daemon "$t" "server" \
+				nc --sctp -l 172.31.110.20 -vn 4443
+	server_pid=$pid
+	ovs_wait ip netns exec server \
+	    ss -lnH sport = :4443 \| grep -q . \
+	    || return 1
+
+	ovs_sbx "$t" ip netns exec client \
+	    nc --sctp -w 2 -zv 172.31.110.20 4443 \
+	    >/dev/null 2>&1 \
+	    && { info "FAIL: connection should fail without flows"
+	         return 1; }
+
+	info "reinstall flows and verify recovery"
+	ovs_add_flow "$t" sctp4 \
+	    'in_port(1),eth(),eth_type(0x0800),ipv4(proto=132),sctp(dst=4443)' \
+	    '2' || return 1
+	ovs_add_flow "$t" sctp4 \
+	    'in_port(2),eth(),eth_type(0x0800),ipv4(proto=132),sctp(src=4443)' \
+	    '1' || return 1
+
+	kill -TERM $server_pid 2>/dev/null
+	wait $server_pid 2>/dev/null
+	echo "server3" | \
+		ovs_netns_spawn_daemon "$t" "server" \
+				nc --sctp -l 172.31.110.20 -vn 4443
+	ovs_wait ip netns exec server \
+	    ss -lnH sport = :4443 \| grep -q . \
+	    || return 1
+
+	ovs_sbx "$t" ip netns exec client \
+	    nc --sctp -i 1 -zv 172.31.110.20 4443 \
+	    || return 1
+
+	return 0
+}
+
 # psample test
 # - use psample to observe packets
 test_psample() {
diff --git a/tools/testing/selftests/net/openvswitch/ovs-dpctl.py b/tools/testing/selftests/net/openvswitch/ovs-dpctl.py
index e1ecfad2c03e..7cfc29ec7e59 100644
--- a/tools/testing/selftests/net/openvswitch/ovs-dpctl.py
+++ b/tools/testing/selftests/net/openvswitch/ovs-dpctl.py
@@ -1982,6 +1982,11 @@ class ovskey(nla):
                 "icmp",
                 ovskey.ovs_key_icmp,
             ),
+            (
+                "OVS_KEY_ATTR_SCTP",
+                "sctp",
+                ovskey.ovs_key_sctp,
+            ),
             (
                 "OVS_KEY_ATTR_TCP_FLAGS",
                 "tcp_flags",
-- 
2.55.0