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

From: Fan Du <[email-masked]>
Date: Mon, 14 Oct 2013 16:33:46 +0800

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 <[email-masked]>
>> Cc: Vlad Yasevich <[email-masked]>
>> Cc: Neil Horman <[email-masked]>
>> Cc: Steffen Klassert <[email-masked]>
>> Acked-by: Vlad Yasevich <[email-masked]>
>> ---
>>   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...

-- 
浮沉随浪只记今朝笑

--fan