Hi Ilya,
Thanks for pointing this out. I looked into this and found that
nc (netcat-openbsd) on Debian/Ubuntu does not have SCTP support at
all. The upstream OpenBSD nc only handles TCP, UDP, and
Unix-domain sockets, and the Debian patches don't add SCTP either.
I see two cleaner alternatives that already have precedent in the
kernel selftests:
1. socat: net/netfilter/nft_queue.sh already uses
"socat -u SCTP-LISTEN:PORT STDOUT" for SCTP data-plane testing.
Many drivers/net/ selftests already gate on require_cmd("socat").
2. A small C helper: similar to sctp_hello.c used by sctp_vrf.sh
and conntrack_sctp_collision.sh. The shell test would call
"./sctp_test server/client IP PORT" instead of ncat.
Which approach would you prefer for v3?
Best regards,
Minxi
侯敏熙 <[email protected]> 于2026年7月13日周一 11:02写道：
> Ah so many thanks for your suggestions, Please forgive me,
> I've always used ncat to write test cases.
>
> I will re-spin this patch.
>
> Ilya Maximets <[email protected]> 于2026年7月13日周一 10:39写道：
>
>> On 7/7/26 5:47 AM, Minxi Hou wrote:
>> > Register OVS_KEY_ATTR_SCTP in the flow key parser so that sctp()
>> > can be used in flow specifications. The ovs_key_sctp class already
>> > exists (with src/dst fields matching the TCP/UDP siblings) but was
>> > not wired into the parser, so the token was silently dropped and the
>> > kernel rejected the flow.
>> >
>> > Add test_sctp_connect_v4 exercising the SCTP flow key with
>> > port-specific matching: sctp(dst=4443) for client-to-server and
>> > sctp(src=4443) for server-to-client.
>> >
>> > Wait for ncat readiness with ovs_wait instead of a fixed sleep so
>> > the test does not race against ncat startup. Use grep -c on the
>> > listening message to distinguish between successive ncat instances
>> > that share the same stderr log. Kill the previous server before
>> > respawning to avoid EADDRINUSE on the SCTP port.
>> >
>> > Signed-off-by: Minxi Hou <[email protected]>
>> > ---
>> > v1 -> v2: replace sleep with ovs_wait on ncat listening output,
>> > kill previous ncat server before respawning to avoid
>> > port conflict (Aaron review feedback)
>> >
>> > .../selftests/net/openvswitch/openvswitch.sh | 102 ++++++++++++++++++
>> > .../selftests/net/openvswitch/ovs-dpctl.py | 5 +
>> > 2 files changed, 107 insertions(+)
>> >
>> > diff --git a/tools/testing/selftests/net/openvswitch/openvswitch.sh
>> b/tools/testing/selftests/net/openvswitch/openvswitch.sh
>> > index 2954245129a2..9c364eeb2ec2 100755
>> > --- a/tools/testing/selftests/net/openvswitch/openvswitch.sh
>> > +++ b/tools/testing/selftests/net/openvswitch/openvswitch.sh
>> > @@ -32,6 +32,7 @@ tests="
>> > dec_ttl ttl: dec_ttl decrements
>> IP TTL
>> > flow_set flow-set: Flow modify
>> > action_set set: SET action rewrites
>> fields
>> > + sctp_connect_v4 sctp: SCTP flow key
>> matching
>> > psample psample: Sampling packets
>> with psample"
>> >
>> > info() {
>> > @@ -443,6 +444,107 @@ test_action_set() {
>> > 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 ncat >/dev/null 2>&1 || return $ksft_skip
>>
>> Not a full review, but can we avoid ncat? We already use nc in other
>> tests, using different implementations of the same thing in different
>> tests doesn't sound like a good idea. On mnay systems nc and ncat
>> will be different implementations with different options and behavior.
>>
>> Best regards, Ilya Maximets.
>>
>
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