[IPSEC] proto: Move transport mode input path into xfrm_mode_transport

Now that we have xfrm_mode objects we can move the transport mode specific
input decapsulation code into xfrm_mode_transport.  This removes duplicate
code as well as unnecessary header movement in case of tunnel mode SAs
since we will discard the original IP header immediately.

This also fixes a minor bug for transport-mode ESP where the IP payload
length is set to the correct value minus the header length (with extension
headers for IPv6).

Of course the other neat thing is that we no longer have to allocate
temporary buffers to hold the IP headers for ESP and IPComp.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 22 deletions

diff --git a/net/ipv6/ipcomp6.c b/net/ipv6/ipcomp6.c
index 48636436028a..cec3be544b69 100644
--- a/net/ipv6/ipcomp6.c
+++ b/net/ipv6/ipcomp6.c
@@ -66,10 +66,8 @@ static LIST_HEAD(ipcomp6_tfms_list);
 static int ipcomp6_input(struct xfrm_state *x, struct sk_buff *skb)
 {
         int err = 0;
-        u8 nexthdr = 0;
-        int hdr_len = skb->h.raw - skb->nh.raw;
-        unsigned char *tmp_hdr = NULL;
         struct ipv6hdr *iph;
+        struct ipv6_comp_hdr *ipch;
         int plen, dlen;
         struct ipcomp_data *ipcd = x->data;
         u8 *start, *scratch;
@@ -86,17 +84,9 @@ static int ipcomp6_input(struct xfrm_state *x, struct sk_buff *skb)
 
         /* Remove ipcomp header and decompress original payload */
         iph = skb->nh.ipv6h;
-        tmp_hdr = kmalloc(hdr_len, GFP_ATOMIC);
-        if (!tmp_hdr)
-                goto out;
-        memcpy(tmp_hdr, iph, hdr_len);
-        nexthdr = *(u8 *)skb->data;
-        skb_pull(skb, sizeof(struct ipv6_comp_hdr)); 
-        skb->nh.raw += sizeof(struct ipv6_comp_hdr);
-        memcpy(skb->nh.raw, tmp_hdr, hdr_len);
-        iph = skb->nh.ipv6h;
-        iph->payload_len = htons(ntohs(iph->payload_len) - sizeof(struct ipv6_comp_hdr));
-        skb->h.raw = skb->data;
+        ipch = (void *)skb->data;
+        skb->h.raw = skb->nh.raw + sizeof(*ipch);
+        __skb_pull(skb, sizeof(*ipch));
 
         /* decompression */
         plen = skb->len;
@@ -125,18 +115,11 @@ static int ipcomp6_input(struct xfrm_state *x, struct sk_buff *skb)
 
         skb_put(skb, dlen - plen);
         memcpy(skb->data, scratch, dlen);
+        err = ipch->nexthdr;
 
-        iph = skb->nh.ipv6h;
-        iph->payload_len = htons(skb->len);
-        
 out_put_cpu:
         put_cpu();
 out:
-        kfree(tmp_hdr);
-        if (err)
-                goto error_out;
-        return nexthdr;
-error_out:
         return err;
 }