Re: [PATCH mptcp-next v23 2/8] selftests: mptcp: connect: check TFO SIOCINQ overflow

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential
issue to consider:
- [Medium] selftests: mptcp: unhandled EOPNOTSUPP in
  wait_for_remote_key() for IPv4 TCP
--

commit 058a45159cca4e12fb9271f3ed25cdefa12d46b9
Author: Geliang Tang <geliang@kernel.org>

selftests: mptcp: connect: check TFO SIOCINQ overflow

This commit adds a SIOCINQ check in mptcp_connect's server mode when the
MPTFO socket option is enabled to detect TFO SIOCINQ overflow regressions.

> diff --git a/tools/testing/selftests/net/mptcp/mptcp_connect.c b/tools/testing/selftests/net/mptcp/mptcp_connect.c
> index 178d98d91fea2..3a72bae43b906 100644
> --- a/tools/testing/selftests/net/mptcp/mptcp_connect.c
> +++ b/tools/testing/selftests/net/mptcp/mptcp_connect.c

[ ... ]

> @@ -1176,6 +1180,28 @@ static void maybe_close(int fd)
>  		close(fd);
>  }
>  
> +static bool wait_for_remote_key(int fd)
> +{
> +	struct mptcp_info info;
> +	int retries = 10;
> +	socklen_t olen;
> +
> +	while (retries > 0) {
> +		olen = sizeof(info);
> +		if (getsockopt(fd, SOL_MPTCP, MPTCP_INFO, &info, &olen) < 0) {
> +			/* Not an MPTCP socket (TCP or fallback), skip wait */
> +			if (errno == ENOPROTOOPT)
> +				return true;
> +			return false;
> +		}

[Severity: Medium]
Should wait_for_remote_key() also check for EOPNOTSUPP here?

For AF_INET TCP sockets (and MPTCP sockets that fell back to TCP),
tcp_getsockopt() delegates non-SOL_TCP levels to ip_getsockopt() ->
do_ip_getsockopt(), which returns -EOPNOTSUPP instead of -ENOPROTOOPT
when level != SOL_IP.  As a result, IPv4 TCP and TCP-fallback test cases
with -o MPTFO return false from wait_for_remote_key() and fail in
main_loop_s() with "TFO: timeout waiting for third ACK".

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/cover.1793969127.git.tanggeliang@kylinos.cn?part=2