tree fdd08812be172d834752c55f580889256341e1a9
parent 3697649ff29e0f647565eed04b27a7779c646a22
author Daniel Borkmann <daniel@iogearbox.net> 1455919526 +0100
committer David S. Miller <davem@davemloft.net> 1456110430 -0500

bpf: fix csum update in bpf_l4_csum_replace helper for udp

When using this helper for updating UDP checksums, we need to extend
this in order to write CSUM_MANGLED_0 for csum computations that result
into 0 as sum. Reason we need this is because packets with a checksum
could otherwise become incorrectly marked as a packet without a checksum.
Likewise, if the user indicates BPF_F_MARK_MANGLED_0, then we should
not turn packets without a checksum into ones with a checksum.

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