{IPv6,xfrm} Add ESN support for AH egress part

This patch add esn support for AH output stage by attaching upper 32bits
sequence number right after packet payload as specified by RFC 4302.

Then the ICV value will guard upper 32bits sequence number as well when
packet going out.

Signed-off-by: Fan Du <fan.du@windriver.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

diff --git a/net/ipv6/ah6.c b/net/ipv6/ah6.c
index 81e496a2e0083c42fe94729a486647aa23c8aed0..89298124c136c5248667d9aa6364ce3ba539f067 100644 (file)
--- a/net/ipv6/ah6.c
+++ b/net/ipv6/ah6.c
@@ -346,6 +346,10 @@ static int ah6_output(struct xfrm_state *x, struct sk_buff *skb)
        struct ip_auth_hdr *ah;
        struct ah_data *ahp;
        struct tmp_ext *iph_ext;
+       int seqhi_len = 0;
+       __be32 *seqhi;
+       int sglists = 0;
+       struct scatterlist *seqhisg;
 
        ahp = x->data;
        ahash = ahp->ahash;
@@ -359,15 +363,22 @@ static int ah6_output(struct xfrm_state *x, struct sk_buff *skb)
        if (extlen)
                extlen += sizeof(*iph_ext);
 
+       if (x->props.flags & XFRM_STATE_ESN) {
+               sglists = 1;
+               seqhi_len = sizeof(*seqhi);
+       }
        err = -ENOMEM;
-       iph_base = ah_alloc_tmp(ahash, nfrags, IPV6HDR_BASELEN + extlen);
+       iph_base = ah_alloc_tmp(ahash, nfrags + sglists, IPV6HDR_BASELEN +
+                               extlen + seqhi_len);
        if (!iph_base)
                goto out;
 
        iph_ext = ah_tmp_ext(iph_base);
-       icv = ah_tmp_icv(ahash, iph_ext, extlen);
+       seqhi = (__be32 *)((char *)iph_ext + extlen);
+       icv = ah_tmp_icv(ahash, seqhi, seqhi_len);
        req = ah_tmp_req(ahash, icv);
        sg = ah_req_sg(ahash, req);
+       seqhisg = sg + nfrags;
 
        ah = ip_auth_hdr(skb);
        memset(ah->auth_data, 0, ahp->icv_trunc_len);
@@ -411,10 +422,15 @@ static int ah6_output(struct xfrm_state *x, struct sk_buff *skb)
        ah->spi = x->id.spi;
        ah->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
 
-       sg_init_table(sg, nfrags);
-       skb_to_sgvec(skb, sg, 0, skb->len);
+       sg_init_table(sg, nfrags + sglists);
+       skb_to_sgvec_nomark(skb, sg, 0, skb->len);
 
-       ahash_request_set_crypt(req, sg, icv, skb->len);
+       if (x->props.flags & XFRM_STATE_ESN) {
+               /* Attach seqhi sg right after packet payload */
+               *seqhi = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
+               sg_set_buf(seqhisg, seqhi, seqhi_len);
+       }
+       ahash_request_set_crypt(req, sg, icv, skb->len + seqhi_len);
        ahash_request_set_callback(req, 0, ah6_output_done, skb);
 
        AH_SKB_CB(skb)->tmp = iph_base;