tree c595df47ba28d6fca8f1deb338c8256d6123c77b
parent 9a49850d0af7b9fd14d091dfe61ef6cb369f86b9
author Tom Herbert <tom@herbertland.com> 1450120786 -0800
committer David S. Miller <davem@davemloft.net> 1450216221 -0500

net: Add driver helper functions to determine checksum offloadability

Add skb_csum_offload_chk driver helper function to determine if a
device with limited checksum offload capabilities is able to offload the
checksum for a given packet.

This patch includes:
  - The skb_csum_offload_chk function. Returns true if checksum is
    offloadable, else false. Optionally, in the case that the checksum
    is not offloable, the function can call skb_checksum_help to resolve
    the checksum. skb_csum_offload_chk also returns whether the checksum
    refers to an encapsulated checksum.
  - Definition of skb_csum_offl_spec structure that caller uses to
    indicate rules about what it can offload (e.g. IPv4/v6, TCP/UDP only,
    whether encapsulated checksums can be offloaded, whether checksum with
    IPv6 extension headers can be offloaded).
  - Ancilary functions called skb_csum_offload_chk_help,
    skb_csum_off_chk_help_cmn, skb_csum_off_chk_help_cmn_v4_only.

Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>