1 files changed, 12 insertions, 22 deletions

diff --git a/net/ipv4/ipcomp.c b/net/ipv4/ipcomp.c
index e787044a851..0bfeb02a5f8 100644
--- a/net/ipv4/ipcomp.c
+++ b/net/ipv4/ipcomp.c
@@ -75,7 +75,6 @@ out:
 static int ipcomp_input(struct xfrm_state *x, struct sk_buff *skb)
 {
 	int err = -ENOMEM;
-	struct iphdr *iph;
 	struct ip_comp_hdr *ipch;
 
 	if (skb_linearize_cow(skb))
@@ -84,12 +83,14 @@ static int ipcomp_input(struct xfrm_state *x, struct sk_buff *skb)
 	skb->ip_summed = CHECKSUM_NONE;
 
 	/* Remove ipcomp header and decompress original payload */
-	iph = ip_hdr(skb);
 	ipch = (void *)skb->data;
-	iph->protocol = ipch->nexthdr;
 	skb->transport_header = skb->network_header + sizeof(*ipch);
 	__skb_pull(skb, sizeof(*ipch));
 	err = ipcomp_decompress(x, skb);
+	if (err)
+		goto out;
+
+	err = ipch->nexthdr;
 
 out:
 	return err;
@@ -98,10 +99,9 @@ out:
 static int ipcomp_compress(struct xfrm_state *x, struct sk_buff *skb)
 {
 	struct ipcomp_data *ipcd = x->data;
-	const int ihlen = ip_hdrlen(skb);
-	const int plen = skb->len - ihlen;
+	const int plen = skb->len;
 	int dlen = IPCOMP_SCRATCH_SIZE;
-	u8 *start = skb->data + ihlen;
+	u8 *start = skb->data;
 	const int cpu = get_cpu();
 	u8 *scratch = *per_cpu_ptr(ipcomp_scratches, cpu);
 	struct crypto_comp *tfm = *per_cpu_ptr(ipcd->tfms, cpu);
@@ -118,7 +118,7 @@ static int ipcomp_compress(struct xfrm_state *x, struct sk_buff *skb)
 	memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen);
 	put_cpu();
 
-	pskb_trim(skb, ihlen + dlen + sizeof(struct ip_comp_hdr));
+	pskb_trim(skb, dlen + sizeof(struct ip_comp_hdr));
 	return 0;
 
 out:
@@ -131,12 +131,8 @@ static int ipcomp_output(struct xfrm_state *x, struct sk_buff *skb)
 	int err;
 	struct ip_comp_hdr *ipch;
 	struct ipcomp_data *ipcd = x->data;
-	int hdr_len = 0;
-	struct iphdr *iph = ip_hdr(skb);
 
-	iph->tot_len = htons(skb->len);
-	hdr_len = iph->ihl * 4;
-	if ((skb->len - hdr_len) < ipcd->threshold) {
+	if (skb->len < ipcd->threshold) {
 		/* Don't bother compressing */
 		goto out_ok;
 	}
@@ -145,25 +141,19 @@ static int ipcomp_output(struct xfrm_state *x, struct sk_buff *skb)
 		goto out_ok;
 
 	err = ipcomp_compress(x, skb);
-	iph = ip_hdr(skb);
 
 	if (err) {
 		goto out_ok;
 	}
 
 	/* Install ipcomp header, convert into ipcomp datagram. */
-	iph->tot_len = htons(skb->len);
-	ipch = (struct ip_comp_hdr *)((char *)iph + iph->ihl * 4);
-	ipch->nexthdr = iph->protocol;
+	ipch = ip_comp_hdr(skb);
+	ipch->nexthdr = *skb_mac_header(skb);
 	ipch->flags = 0;
 	ipch->cpi = htons((u16 )ntohl(x->id.spi));
-	iph->protocol = IPPROTO_COMP;
-	ip_send_check(iph);
-	return 0;
-
+	*skb_mac_header(skb) = IPPROTO_COMP;
 out_ok:
-	if (x->props.mode == XFRM_MODE_TUNNEL)
-		ip_send_check(iph);
+	skb_push(skb, -skb_network_offset(skb));
 	return 0;
 }