How can I attach a BPF_PROG_TYPE_SK_MSG prog

[fengzx33]

I found that libbpfgo haven't an api, which can attach SEC("sk_msg") , what should i do? thanks

example: https://github.com/dafu-wu/istio-tcpip-bypass/blob/796d738babee7da77815ad2819a69d37d8472dea/bpf/bpf_redir.c#L9

[geyslan]

Hi @fengzx33, as I mentioned in #330 (comment), currently libbpfgo lacks support of bpf_msg_* API.

libbpf doesn't use them internally, it just externalizes them.

what should i do?

Would you be interested in implementing (wrapping) these uapi in libbpfgo making them available?

[fengzx33]

ok，I will give it a try, and if you have any support regarding this matter, please @ me promptly

[geyslan]

Awesome. Perhaps these @mozillazg PR can be used as a basis for your effort:

• Add AttachIter to wrap bpf_program__attach_iter #254
• Add AttachNetns to wrap bpf_program__attach_netns #205

Any questions, bring them to us.

[rafaeldtinoco]

maybe I'm missing context here, but those helpers are to be used by eBPF programs and not by userland (despite being declared in UAPI, because of kernel off-tree compilation needs), no ?

Also, @mozillazg has provided a good example of a socket program in the issue: #329, which could also serve as basis for an sk_msg example as well.

[fengzx33]

@rafaeldtinoco I think you're right. I do need a userland program to attach sk_msg. Can you provide an example for that?