Re: [PATCHv3 net] {xfrm, sctp} Stick to software crc32 even if hardware is capable of that

[Vlad Yasevich <vyasevich@gmail.com>]

On 10/15/2013 05:19 AM, Fan Du wrote:
> igb/ixgbe have hardware sctp checksum support, when this feature is enabled
> and also IPsec is armed to protect sctp traffic, ugly things happened as
> xfrm_output checks CHECKSUM_PARTIAL to do check sum operation(sum every thing
> up and pack the 16bits result in the checksum field). The result is fail
> establishment of sctp communication.
>
> Signed-off-by: Fan Du <fan.du@windriver.com>
> Cc: Vlad Yasevich <vyasevich@gmail.com>
> Cc: Neil Horman <nhorman@tuxdriver.com>
> Cc: Steffen Klassert <steffen.klassert@secunet.com>
> Acked-by: Vlad Yasevich <vyasevich@gmail.com>

Looks good to me.

-vlad

> ---
> v3:
>    - Rename is_xfrm_armed by dst_xfrm
>    - Move this funtion in include/net/dst.h
>
> v2:
>    - Split v1 into two separate patches.
>
> ---
>   include/net/dst.h |   12 ++++++++++++
>   net/sctp/output.c |    3 ++-
>   2 files changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/include/net/dst.h b/include/net/dst.h
> index 211dcf1..44995c1 100644
> --- a/include/net/dst.h
> +++ b/include/net/dst.h
> @@ -478,10 +478,22 @@ static inline struct dst_entry *xfrm_lookup(struct net *net,
>   {
>   	return dst_orig;
>   }
> +
> +static inline struct xfrm_state *dst_xfrm(const struct dst_entry *dst)
> +{
> +	return NULL;
> +}
> +
>   #else
>   struct dst_entry *xfrm_lookup(struct net *net, struct dst_entry *dst_orig,
>   			      const struct flowi *fl, struct sock *sk,
>   			      int flags);
> +
> +/* skb attached with this dst needs transformation if dst->xfrm is valid */
> +static inline struct xfrm_state *dst_xfrm(const struct dst_entry *dst)
> +{
> +	return dst->xfrm;
> +}
>   #endif
>
>   #endif /* _NET_DST_H */
> diff --git a/net/sctp/output.c b/net/sctp/output.c
> index 0ac3a65..24b3718 100644
> --- a/net/sctp/output.c
> +++ b/net/sctp/output.c
> @@ -536,7 +536,8 @@ int sctp_packet_transmit(struct sctp_packet *packet)
>   	 * by CRC32-C as described in <draft-ietf-tsvwg-sctpcsum-02.txt>.
>   	 */
>   	if (!sctp_checksum_disable) {
> -		if (!(dst->dev->features & NETIF_F_SCTP_CSUM)) {
> +		if (!(dst->dev->features & NETIF_F_SCTP_CSUM) ||
> +			(dst_xfrm(dst) != NULL)) {
>   			__u32 crc32 = sctp_start_cksum((__u8 *)sh, cksum_buf_len);
>
>   			/* 3) Put the resultant value into the checksum field in the
>