On Wed, Jun 17, 2020 at 02:15:37PM -0700, Yonghong Song wrote:
> A new field bpf_seq_afinfo is added to tcp_iter_state
> to provide bpf tcp iterator afinfo. There are two
> reasons on why we did this.
>
> First, the current way to get afinfo from PDE_DATA
> does not work for bpf iterator as its seq_file
> inode does not conform to /proc/net/{tcp,tcp6}
> inode structures. More specifically, anonymous
> bpf iterator will use an anonymous inode which
> is shared in the system and we cannot change inode
> private data structure at all.
>
> Second, bpf iterator for tcp/tcp6 wants to
> traverse all tcp and tcp6 sockets in one pass
> and bpf program can control whether they want
> to skip one sk_family or not. Having a different
> afinfo with family AF_UNSPEC make it easier
> to understand in the code.
Acked-by: Martin KaFai Lau <kafai@xxxxxx>
