Re: [PATCH bpf-next/net v2 7/7] selftests/bpf: Add mptcp_subflow bpf_iter subtest

[Matthieu Baerts <matttbe@kernel.org>]

Hi Geliang,

(only with the MPTCP list)

On 24/01/2025 02:38, Martin KaFai Lau wrote:
> On 12/19/24 7:46 AM, Matthieu Baerts (NGI0) wrote:
>> +SEC("cgroup/getsockopt")
>> +int iters_subflow(struct bpf_sockopt *ctx)
>> +{
>> +    struct mptcp_subflow_context *subflow;
>> +    struct bpf_sock *sk = ctx->sk;
>> +    struct sock *ssk = NULL;
>> +    struct mptcp_sock *msk;
>> +    int local_ids = 0;
>> +
>> +    if (ctx->level != SOL_TCP || ctx->optname != TCP_IS_MPTCP)
>> +        return 1;
>> +
>> +    msk = bpf_skc_to_mptcp_sock(sk);
>> +    if (!msk || msk->pm.server_side || !msk->pm.subflows)
>> +        return 1;
>> +
>> +    msk = bpf_mptcp_sock_acquire(msk);
>> +    if (!msk)
>> +        return 1;
>> +    bpf_for_each(mptcp_subflow, subflow, msk) {
>> +        /* Here MPTCP-specific packet scheduler kfunc can be called:
>> +         * this test is not doing anything really useful, only to
>> +         * verify the iteration works.
>> +         */
>> +
>> +        local_ids += subflow->subflow_id;
>> +
>> +        /* only to check the following kfunc works */
>> +        ssk = mptcp_subflow_tcp_sock(subflow);
> 
> It is good to have test cases to exercise the new iter and kfunc. Thanks.
> 
> However, it seems not useful to show how it will be used in the future
> packet/subflow scheduler. iiuc, the core piece is in bpf_struct_ops.
> Without it, it is hard to comment. Any RFC patches ready to be posted?

If it is easier, we can probably share a link to your git repo
containing the WIP patches.

Cheers,
Matt
-- 
Sponsored by the NGI0 Core fund.