Subject: Re: [PATCHv3 net-next 2/5] {IPv4,xfrm} Add ESN support for AH ingress part

From: Steffen Klassert <[email-masked]>
Date: Tue, 14 Jan 2014 11:09:00 +0100

On Tue, Jan 14, 2014 at 06:01:32PM +0800, Fan Du wrote:
> 
> 
> On 2014年01月14日 17:54, Steffen Klassert wrote:
> >On Tue, Jan 14, 2014 at 09:39:09AM +0800, Fan Du wrote:
> >>@@ -381,7 +393,14 @@ static int ah_input(struct xfrm_state *x, struct sk_buff *skb)
> >>  	sg_init_table(sg, nfrags);
> >>  	skb_to_sgvec(skb, sg, 0, skb->len);
> >>
> >>-	ahash_request_set_crypt(req, sg, icv, skb->len);
> >>+	if (x->props.flags&  XFRM_STATE_ESN) {
> >>+		sg_unmark_end(&sg[nfrags - 1]);
> >>+		/* Attach seqhi sg right after packet payload */
> >>+		*seqhi = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
> >
> >This is ah_input(), so you should use the high bits of the input
> >sequence number here. The ipv6 patch has the same problem.
> 
> ok, I will fix this.
> 
> >
> >>+		sg_init_table(seqhisg, sglists);
> >
> >Why do you add a separate SG table for this?
> 
> It just initialize a single seqhisg, which is actually followed behind packet payload sg table.
> initialized seqhisg actually mark itself as the end of sg list.
> 

Why don't you just add this entry to the existing SG table?