tree ca92a811b501957c1e876290d305aaf81c8d9aff
parent 5888b93b750609680735d6b8b737703083ef40ff
author Alexei Starovoitov <ast@plumgrid.com> 1427933533 -0700
committer David S. Miller <davem@davemloft.net> 1428352955 -0400

tc: bpf: add checksum helpers

Commit 608cd71a9c7c ("tc: bpf: generalize pedit action") has added the
possibility to mangle packet data to BPF programs in the tc pipeline.
This patch adds two helpers bpf_l3_csum_replace() and bpf_l4_csum_replace()
for fixing up the protocol checksums after the packet mangling.

It also adds 'flags' argument to bpf_skb_store_bytes() helper to avoid
unnecessary checksum recomputations when BPF programs adjusting l3/l4
checksums and documents all three helpers in uapi header.

Moreover, a sample program is added to show how BPF programs can make use
of the mangle and csum helpers.

Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>