Re: [PATCHv2 RESEND] {xfrm, sctp} Stick to software crc32 even if hardware is capable of that

[Fan Du <fan.du@windriver.com>]

On 2013年10月14日 22:16, Vlad Yasevich wrote:
>
>
> Fan Du<fan.du@windriver.com>  wrote:
>
>>
>>
>> On 2013年10月14日 16:07, Daniel Borkmann wrote:
>>> On 10/14/2013 09:27 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>
>>>> ---
>>>>    net/sctp/output.c |   14 +++++++++++++-
>>>>    1 file changed, 13 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/net/sctp/output.c b/net/sctp/output.c
>>>> index 0ac3a65..6de6402 100644
>>>> --- a/net/sctp/output.c
>>>> +++ b/net/sctp/output.c
>>>> @@ -372,6 +372,16 @@ static void sctp_packet_set_owner_w(struct
>> sk_buff *skb, struct sock *sk)
>>>>        atomic_inc(&sk->sk_wmem_alloc);
>>>>    }
>>>>
>>>> +static int is_xfrm_armed(struct dst_entry *dst)
>>>> +{
>>>> +#ifdef CONFIG_XFRM
>>>> +    /* If dst->xfrm is valid, this skb needs to be transformed */
>>>> +    return dst->xfrm != NULL;
>>>> +#else
>>>> +    return 0;
>>>> +#endif
>>>> +}
>>>
>>> Instead of putting this into SCTP code, isn't the above rather a
>> candidate for
>>> include/net/xfrm.h, e.g. as ... bool xfrm_is_armed(...) ?
>>
>> Should be in such style in terms of its name, but this is truly SCTP
>> specific in this scenario.
>> No one elsewhere barely need this as far as I can tell...
>
> It almost begs for dst_xfrm() function that returns NULL or dst->xfrm.
> Thar can live in dst code.

Ok, I will show my love in such style in v3.

> -vlad
>

-- 
浮沉随浪只记今朝笑

--fan