Re: [PATCH mptcp-next 2/2] selftests/bpf: Add getsockopt to inspect mptcp subflow

[Martin KaFai Lau <martin.lau@linux.dev>]

On 8/21/24 2:37 AM, Matthieu Baerts wrote:
> Hi Geliang,
> 
> Thank you for your reply!
> 
> On 21/08/2024 10:00, Geliang Tang wrote:
>> On Tue, 2024-08-20 at 11:48 +0200, Matthieu Baerts wrote:
>>> On 20/08/2024 10:44, Geliang Tang wrote:
> (...)
> 
>>>> diff --git a/tools/testing/selftests/bpf/prog_tests/mptcp.c
>>>> b/tools/testing/selftests/bpf/prog_tests/mptcp.c
>>>> index 69fdcb28249d..2178db94f764 100644
>>>> --- a/tools/testing/selftests/bpf/prog_tests/mptcp.c
>>>> +++ b/tools/testing/selftests/bpf/prog_tests/mptcp.c
>>>> @@ -383,6 +383,7 @@ static void run_subflow(char *new)
>>>>   {
>>>>   	int server_fd, client_fd, err;
>>>>   	char cc[TCP_CA_NAME_MAX];
>>>> +	unsigned int mark;
>>>>   	socklen_t len;
>>>>   
>>>>   	server_fd = start_mptcp_server(AF_INET, ADDR_1, PORT_1,
>>>> 0);
>>>> @@ -407,6 +408,10 @@ static void run_subflow(char *new)
>>>>   	ASSERT_OK(ss_search(ADDR_1, new), "ss_search new cc");
>>>>   	ASSERT_OK(ss_search(ADDR_2, cc), "ss_search default cc");
>>> I guess the next steps is to remove these 'ss_search()', right?
>> We can keep it for double checks.
> I would not mind, even if 'ss | grep' is used in other BPF tests, but I
> understood from Martin he prefers not to depend on external tools as
> much as possible. It should indeed ease the maintenance.

I would prefer to avoid the 'ss | grep'. The other bpf selftests using this "ss 
| grep" should be in the .sh which is not in the test_progs and not run by bpf 
CI. They are there to loop-waiting for something. The ss usage hopefully will be 
removed when eventually migrating the .sh tests to test_progs. At least the one 
in test_tc_tunnel.sh should be doable once moved to test_progs. Haven't looked 
at the test_xdp_features.sh yet.

Thanks for trying the getsockopt approach and it turns out working well.