Re: [RFC PATCH bpf-next 0/5] Add bpf_link support for sk_msg prog

From: Yonghong Song <yonghong.song@linux.dev>
To: Jakub Sitnicki <jakub@cloudflare.com>
Cc: bpf@vger.kernel.org, Alexei Starovoitov <ast@kernel.org>,
	Andrii Nakryiko <andrii@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	John Fastabend <john.fastabend@gmail.com>,
	kernel-team@fb.com, Martin KaFai Lau <martin.lau@kernel.org>
Subject: Re: [RFC PATCH bpf-next 0/5] Add bpf_link support for sk_msg prog
Date: Mon, 11 Mar 2024 14:53:22 -0700	[thread overview]
Message-ID: <e4b25a0d-00b8-400d-a92d-079d7540ac4f@linux.dev> (raw)
In-Reply-To: <87jzmarkut.fsf@cloudflare.com>

On 3/7/24 5:01 AM, Jakub Sitnicki wrote:
> On Tue, Mar 05, 2024 at 12:21 PM -08, Yonghong Song wrote:
>> One of our internal services started to use sk_msg program and currently
>> it used existing prog attach/detach2 as demonstrated in selftests.
>> But attach/detach of all other bpf programs are based on bpf_link.
>> Consistent attach/detach APIs for all programs will make things easy to
>> undersand and less error prone. So this patch added bpf_link
>> support for BPF_PROG_TYPE_SK_MSG.
>>
>> I marked the patch as RFC as not all functionality are covered
>> by tests yet, e.g. update_prog(). Maybe somebody can suggest
>> an existing test which I can look into.
>> Or maybe some other tests need to be added as well.
> I have a general remark, not specific to this work.
>
> We can't attach with links from CLI, apart from when auto-attach is
> supported.  `bpftool prog attach` doesn't use bpf links. For instance:
>
> bpftool prog attach \
>          pinned /sys/fs/bpf/test/sk_msg_prog \
>          sk_msg_verdict \
>          pinned /sys/fs/bpf/test/sock_map
>
> Is there a plan for the CLI tooling to support it?

As far as I know, there is no plan to support this. Of course, somebody
could try to implement this ...