Subject: Re: [PATCH net-next 1/4] bpf: allow bpf programs to tail-call other bpf programs

From: Alexei Starovoitov <[email-masked]>
Date: Tue, 19 May 2015 17:18:44 -0700

On 5/19/15 5:13 PM, Andy Lutomirski wrote:
>
> IMO this is starting to get a bit ugly.  Would it be possible to have
> the program dereference the subprogram reference itself from the jump
> table?  There would have to be a verifier type that represents a
> reference to a program tail-call entry point, but that seems better
> than having this weird indirection.

Which part? I don't think you've looked at examples yet.
network parser has to call itself. Otherwise we cannot parse 10 mpls
labels or TLVs.
Indirection via jump_table also has to be there.
We need to dynamically add and remove programs form this jump table.
It cannot be all static.