[IPSEC]: Move IP length/checksum setting out of transforms

This patch moves the setting of the IP length and checksum fields out of
the transforms and into the xfrmX_output functions.  This would help future
efforts in merging the transforms themselves.

It also adds an optimisation to ipcomp due to the fact that the transport
offset is guaranteed to be zero.

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

7 files changed, 11 insertions, 28 deletions

diff --git a/net/ipv6/esp6.c b/net/ipv6/esp6.c
index a64295d164e..9eb92859835 100644
--- a/net/ipv6/esp6.c
+++ b/net/ipv6/esp6.c
@@ -43,7 +43,6 @@
 static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
 {
 	int err;
-	struct ipv6hdr *top_iph;
 	struct ip_esp_hdr *esph;
 	struct crypto_blkcipher *tfm;
 	struct blkcipher_desc desc;
@@ -85,9 +84,7 @@ static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
 	pskb_put(skb, trailer, clen - skb->len);
 
 	skb_push(skb, -skb_network_offset(skb));
-	top_iph = ipv6_hdr(skb);
 	esph = ip_esp_hdr(skb);
-	top_iph->payload_len = htons(skb->len + alen - sizeof(*top_iph));
 	*(skb_tail_pointer(trailer) - 1) = *skb_mac_header(skb);
 	*skb_mac_header(skb) = IPPROTO_ESP;
 
diff --git a/net/ipv6/ipcomp6.c b/net/ipv6/ipcomp6.c
index 8f3f32faaf4..28fc8edfdc3 100644
--- a/net/ipv6/ipcomp6.c
+++ b/net/ipv6/ipcomp6.c
@@ -119,20 +119,15 @@ out:
 static int ipcomp6_output(struct xfrm_state *x, struct sk_buff *skb)
 {
 	int err;
-	struct ipv6hdr *top_iph;
 	struct ip_comp_hdr *ipch;
 	struct ipcomp_data *ipcd = x->data;
 	int plen, dlen;
 	u8 *start, *scratch;
 	struct crypto_comp *tfm;
 	int cpu;
-	int hdr_len;
-
-	skb_push(skb, -skb_network_offset(skb));
-	hdr_len = skb_transport_offset(skb);
 
 	/* check whether datagram len is larger than threshold */
-	if ((skb->len - hdr_len) < ipcd->threshold) {
+	if (skb->len < ipcd->threshold) {
 		goto out_ok;
 	}
 
@@ -140,9 +135,9 @@ static int ipcomp6_output(struct xfrm_state *x, struct sk_buff *skb)
 		goto out_ok;
 
 	/* compression */
-	plen = skb->len - hdr_len;
+	plen = skb->len;
 	dlen = IPCOMP_SCRATCH_SIZE;
-	start = skb_transport_header(skb);
+	start = skb->data;
 
 	cpu = get_cpu();
 	scratch = *per_cpu_ptr(ipcomp6_scratches, cpu);
@@ -155,13 +150,9 @@ static int ipcomp6_output(struct xfrm_state *x, struct sk_buff *skb)
 	}
 	memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen);
 	put_cpu();
-	pskb_trim(skb, hdr_len + dlen + sizeof(struct ip_comp_hdr));
+	pskb_trim(skb, dlen + sizeof(struct ip_comp_hdr));
 
 	/* insert ipcomp header and replace datagram */
-	top_iph = ipv6_hdr(skb);
-
-	top_iph->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
-
 	ipch = ip_comp_hdr(skb);
 	ipch->nexthdr = *skb_mac_header(skb);
 	ipch->flags = 0;
@@ -169,6 +160,8 @@ static int ipcomp6_output(struct xfrm_state *x, struct sk_buff *skb)
 	*skb_mac_header(skb) = IPPROTO_COMP;
 
 out_ok:
+	skb_push(skb, -skb_network_offset(skb));
+
 	return 0;
 }
 
diff --git a/net/ipv6/mip6.c b/net/ipv6/mip6.c
index 0e7a60f7393..7fd841d4101 100644
--- a/net/ipv6/mip6.c
+++ b/net/ipv6/mip6.c
@@ -155,7 +155,6 @@ static int mip6_destopt_output(struct xfrm_state *x, struct sk_buff *skb)
 
 	skb_push(skb, -skb_network_offset(skb));
 	iph = ipv6_hdr(skb);
-	iph->payload_len = htons(skb->len - sizeof(*iph));
 
 	nexthdr = *skb_mac_header(skb);
 	*skb_mac_header(skb) = IPPROTO_DSTOPTS;
@@ -370,7 +369,6 @@ static int mip6_rthdr_output(struct xfrm_state *x, struct sk_buff *skb)
 
 	skb_push(skb, -skb_network_offset(skb));
 	iph = ipv6_hdr(skb);
-	iph->payload_len = htons(skb->len - sizeof(*iph));
 
 	nexthdr = *skb_mac_header(skb);
 	*skb_mac_header(skb) = IPPROTO_ROUTING;
diff --git a/net/ipv6/xfrm6_mode_beet.c b/net/ipv6/xfrm6_mode_beet.c
index 42c6ef839e5..13bb1e85676 100644
--- a/net/ipv6/xfrm6_mode_beet.c
+++ b/net/ipv6/xfrm6_mode_beet.c
@@ -22,8 +22,6 @@
 /* Add encapsulation header.
  *
  * The top IP header will be constructed per draft-nikander-esp-beet-mode-06.txt.
- * The following fields in it shall be filled in by x->type->output:
- *	payload_len
  */
 static int xfrm6_beet_output(struct xfrm_state *x, struct sk_buff *skb)
 {
diff --git a/net/ipv6/xfrm6_mode_tunnel.c b/net/ipv6/xfrm6_mode_tunnel.c
index e79c6bdf71c..ea228387911 100644
--- a/net/ipv6/xfrm6_mode_tunnel.c
+++ b/net/ipv6/xfrm6_mode_tunnel.c
@@ -33,9 +33,7 @@ static inline void ip6ip_ecn_decapsulate(struct sk_buff *skb)
 
 /* Add encapsulation header.
  *
- * The top IP header will be constructed per RFC 2401.  The following fields
- * in it shall be filled in by x->type->output:
- *	payload_len
+ * The top IP header will be constructed per RFC 2401.
  */
 static int xfrm6_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
 {
diff --git a/net/ipv6/xfrm6_output.c b/net/ipv6/xfrm6_output.c
index f21596f8998..4618c18e611 100644
--- a/net/ipv6/xfrm6_output.c
+++ b/net/ipv6/xfrm6_output.c
@@ -47,6 +47,7 @@ static inline int xfrm6_output_one(struct sk_buff *skb)
 {
 	struct dst_entry *dst = skb->dst;
 	struct xfrm_state *x = dst->xfrm;
+	struct ipv6hdr *iph;
 	int err;
 
 	if (x->props.mode == XFRM_MODE_TUNNEL) {
@@ -59,6 +60,9 @@ static inline int xfrm6_output_one(struct sk_buff *skb)
 	if (err)
 		goto error_nolock;
 
+	iph = ipv6_hdr(skb);
+	iph->payload_len = htons(skb->len - sizeof(*iph));
+
 	IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED;
 	err = 0;
 
diff --git a/net/ipv6/xfrm6_tunnel.c b/net/ipv6/xfrm6_tunnel.c
index 00a1a3e5237..3f8a3abde67 100644
--- a/net/ipv6/xfrm6_tunnel.c
+++ b/net/ipv6/xfrm6_tunnel.c
@@ -242,12 +242,7 @@ EXPORT_SYMBOL(xfrm6_tunnel_free_spi);
 
 static int xfrm6_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
 {
-	struct ipv6hdr *top_iph;
-
 	skb_push(skb, -skb_network_offset(skb));
-	top_iph = ipv6_hdr(skb);
-	top_iph->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
-
 	return 0;
 }