netdev - Re: [PATCH bpf-next] bpf: bpf_{g,s}etsockopt for struct bpf

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Date:   Tue, 28 Apr 2020 20:32:29 -0700
From:   Alexei Starovoitov <alexei.starovoitov@...il.com>
To:     Stanislav Fomichev <sdf@...gle.com>
Cc:     netdev@...r.kernel.org, bpf@...r.kernel.org, davem@...emloft.net,
        ast@...nel.org, daniel@...earbox.net, kafai@...com
Subject: Re: [PATCH bpf-next] bpf: bpf_{g,s}etsockopt for struct bpf_sock

On Tue, Apr 28, 2020 at 11:57:19AM -0700, Stanislav Fomichev wrote:
> Currently, bpf_getsocktop and bpf_setsockopt helpers operate on the
> 'struct bpf_sock_ops' context in BPF_PROG_TYPE_CGROUP_SOCKOPT program.
> Let's generalize them and make the first argument be 'struct bpf_sock'.
> That way, in the future, we can allow those helpers in more places.
> 
> BPF_PROG_TYPE_CGROUP_SOCKOPT still has the existing helpers that operate
> on 'struct bpf_sock_ops', but we add new bpf_{g,s}etsockopt that work
> on 'struct bpf_sock'. [Alternatively, for BPF_PROG_TYPE_CGROUP_SOCKOPT,
> we can enable them both and teach verifier to pick the right one
> based on the context (bpf_sock_ops vs bpf_sock).]
> 
> As an example, let's allow those 'struct bpf_sock' based helpers to
> be called from the BPF_CGROUP_INET{4,6}_CONNECT hooks. That way
> we can override CC before the connection is made.
> 
> Signed-off-by: Stanislav Fomichev <sdf@...gle.com>

Looks good to me and safety checks seem to be correct.
Martin,
could you please help review as well?