[IPSEC]: Move generic encap code into xfrm6_output.

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

net/ipv6/Makefile

@@ -11,7 +11,7 @@ ipv6-objs :=	af_inet6.o anycast.o ip6_output.o ip6_input.o addrconf.o sit.o \
 		ip6_flowlabel.o ipv6_syms.o
 
 ipv6-$(CONFIG_XFRM) += xfrm6_policy.o xfrm6_state.o xfrm6_input.o \
-	xfrm6_tunnel.o
+	xfrm6_tunnel.o xfrm6_output.o
 ipv6-objs += $(ipv6-y)
 
 obj-$(CONFIG_INET6_AH) += ah6.o

net/ipv6/ah6.c

@@ -158,70 +158,55 @@ static int ipv6_clear_mutable_options(struct ipv6hdr *iph, int len)
 int ah6_output(struct sk_buff **pskb)
 {
 	int err;
-	int hdr_len = sizeof(struct ipv6hdr);
+	int extlen;
 	struct dst_entry *dst = (*pskb)->dst;
 	struct xfrm_state *x  = dst->xfrm;
-	struct ipv6hdr *iph = NULL;
+	struct ipv6hdr *top_iph;
 	struct ip_auth_hdr *ah;
 	struct ah_data *ahp;
 	u8 nexthdr;
+	char tmp_base[8];
+	struct {
+		struct in6_addr daddr;
+		char hdrs[0];
+	} *tmp_ext;
 
-	if ((*pskb)->ip_summed == CHECKSUM_HW) {
-		err = skb_checksum_help(pskb, 0);
-		if (err)
-			goto error_nolock;
-	}
-
-	spin_lock_bh(&x->lock);
-	err = xfrm_state_check(x, *pskb);
-	if (err)
-		goto error;
+	top_iph = (struct ipv6hdr *)(*pskb)->data;
+	top_iph->payload_len = htons((*pskb)->len - sizeof(*top_iph));
 
-	if (x->props.mode) {
-		err = xfrm6_tunnel_check_size(*pskb);
-		if (err)
-			goto error;
+	nexthdr = *(*pskb)->nh.raw;
+	*(*pskb)->nh.raw = IPPROTO_AH;
 
-		iph = (*pskb)->nh.ipv6h;
-		(*pskb)->nh.ipv6h = (struct ipv6hdr*)skb_push(*pskb, x->props.header_len);
-		(*pskb)->nh.ipv6h->version = 6;
-		(*pskb)->nh.ipv6h->payload_len = htons((*pskb)->len - sizeof(struct ipv6hdr));
-		(*pskb)->nh.ipv6h->nexthdr = IPPROTO_AH;
-		ipv6_addr_copy(&(*pskb)->nh.ipv6h->saddr,
-			       (struct in6_addr *) &x->props.saddr);
-		ipv6_addr_copy(&(*pskb)->nh.ipv6h->daddr,
-			       (struct in6_addr *) &x->id.daddr);
-		ah = (struct ip_auth_hdr*)((*pskb)->nh.ipv6h+1);
-		ah->nexthdr = IPPROTO_IPV6;
-	} else {
-		u8 *prevhdr;
-
-		hdr_len = ip6_find_1stfragopt(*pskb, &prevhdr);
-		nexthdr = *prevhdr;
-		*prevhdr = IPPROTO_AH;
-		iph = kmalloc(hdr_len, GFP_ATOMIC);
-		if (!iph) {
+	/* When there are no extension headers, we only need to save the first
+	 * 8 bytes of the base IP header.
+	 */
+	memcpy(tmp_base, top_iph, sizeof(tmp_base));
+
+	tmp_ext = NULL;
+	extlen = (*pskb)->h.raw - (unsigned char *)(top_iph + 1);
+	if (extlen) {
+		extlen += sizeof(*tmp_ext);
+		tmp_ext = kmalloc(extlen, GFP_ATOMIC);
+		if (!tmp_ext) {
 			err = -ENOMEM;
 			goto error;
 		}
-		memcpy(iph, (*pskb)->data, hdr_len);
-		(*pskb)->nh.ipv6h = (struct ipv6hdr*)skb_push(*pskb, x->props.header_len);
-		iph->payload_len = htons((*pskb)->len - sizeof(struct ipv6hdr));
-		memcpy((*pskb)->nh.ipv6h, iph, hdr_len);
-		err = ipv6_clear_mutable_options((*pskb)->nh.ipv6h, hdr_len);
+		memcpy(tmp_ext, &top_iph->daddr, extlen);
+		err = ipv6_clear_mutable_options(top_iph,
+						 extlen - sizeof(*tmp_ext) +
+						 sizeof(*top_iph));
 		if (err)
 			goto error_free_iph;
+	}
 
-		ah = (struct ip_auth_hdr*)((*pskb)->nh.raw+hdr_len);
-		(*pskb)->h.raw = (unsigned char*) ah;
+	ah = (struct ip_auth_hdr *)(*pskb)->h.raw;
 	ah->nexthdr = nexthdr;
-	}
 
-	(*pskb)->nh.ipv6h->priority    = 0;
-	(*pskb)->nh.ipv6h->flow_lbl[0] = 0;
-	(*pskb)->nh.ipv6h->flow_lbl[1] = 0;
-	(*pskb)->nh.ipv6h->flow_lbl[2] = 0;
-	(*pskb)->nh.ipv6h->hop_limit    = 0;
+	top_iph->priority    = 0;
+	top_iph->flow_lbl[0] = 0;
+	top_iph->flow_lbl[1] = 0;
+	top_iph->flow_lbl[2] = 0;
+	top_iph->hop_limit   = 0;
 
 	ahp = x->data;
 	ah->hdrlen  = (XFRM_ALIGN8(sizeof(struct ipv6_auth_hdr) + 
@@ -232,35 +217,16 @@ int ah6_output(struct sk_buff **pskb)
 	ah->seq_no = htonl(++x->replay.oseq);
 	ahp->icv(ahp, *pskb, ah->auth_data);
 
-	if (x->props.mode) {
-		(*pskb)->nh.ipv6h->hop_limit   = iph->hop_limit;
-		(*pskb)->nh.ipv6h->priority    = iph->priority; 	
-		(*pskb)->nh.ipv6h->flow_lbl[0] = iph->flow_lbl[0];
-		(*pskb)->nh.ipv6h->flow_lbl[1] = iph->flow_lbl[1];
-		(*pskb)->nh.ipv6h->flow_lbl[2] = iph->flow_lbl[2];
-		if (x->props.flags & XFRM_STATE_NOECN)
-			IP6_ECN_clear((*pskb)->nh.ipv6h);
-	} else {
-		memcpy((*pskb)->nh.ipv6h, iph, hdr_len);
-		kfree (iph);
-	}
-
-	(*pskb)->nh.raw = (*pskb)->data;
+	err = 0;
 
-	x->curlft.bytes += (*pskb)->len;
-	x->curlft.packets++;
-	spin_unlock_bh(&x->lock);
-	if (((*pskb)->dst = dst_pop(dst)) == NULL) {
-		err = -EHOSTUNREACH;
-		goto error_nolock;
-	}
-	return NET_XMIT_BYPASS;
+	memcpy(top_iph, tmp_base, sizeof(tmp_base));
+	if (tmp_ext) {
+		memcpy(&top_iph->daddr, tmp_ext, extlen);
 error_free_iph:
-	kfree(iph);
+		kfree(tmp_ext);
+	}
+
 error:
-	spin_unlock_bh(&x->lock);
-error_nolock:
-	kfree_skb(*pskb);
 	return err;
 }
 

net/ipv6/esp6.c

@@ -41,10 +41,10 @@
 int esp6_output(struct sk_buff **pskb)
 {
 	int err;
-	int hdr_len = 0;
+	int hdr_len;
 	struct dst_entry *dst = (*pskb)->dst;
 	struct xfrm_state *x  = dst->xfrm;
-	struct ipv6hdr *iph = NULL, *top_iph;
+	struct ipv6hdr *top_iph;
 	struct ipv6_esp_hdr *esph;
 	struct crypto_tfm *tfm;
 	struct esp_data *esp;
@@ -53,37 +53,13 @@ int esp6_output(struct sk_buff **pskb)
 	int clen;
 	int alen;
 	int nfrags;
-	u8 *prevhdr;
-	u8 nexthdr = 0;
 
-	if ((*pskb)->ip_summed == CHECKSUM_HW) {
-		err = skb_checksum_help(pskb, 0);
-		if (err)
-			goto error_nolock;
-	}
-
-	spin_lock_bh(&x->lock);
-	err = xfrm_state_check(x, *pskb);
-	if (err)
-		goto error;
+	esp = x->data;
+	hdr_len = (*pskb)->h.raw - (*pskb)->data +
+		  sizeof(*esph) + esp->conf.ivlen;
 
-	if (x->props.mode) {
-		err = xfrm6_tunnel_check_size(*pskb);
-		if (err)
-			goto error;
-	} else {
-		/* Strip IP header in transport mode. Save it. */
-		hdr_len = ip6_find_1stfragopt(*pskb, &prevhdr);
-		nexthdr = *prevhdr;
-		*prevhdr = IPPROTO_ESP;
-		iph = kmalloc(hdr_len, GFP_ATOMIC);
-		if (!iph) {
-			err = -ENOMEM;
-			goto error;
-		}
-		memcpy(iph, (*pskb)->nh.raw, hdr_len);
+	/* Strip IP+ESP header. */
 	__skb_pull(*pskb, hdr_len);
-	}
 
 	/* Now skb is pure payload to encrypt */
 	err = -ENOMEM;
@@ -91,7 +67,6 @@ int esp6_output(struct sk_buff **pskb)
 	/* Round to block size */
 	clen = (*pskb)->len;
 
-	esp = x->data;
 	alen = esp->auth.icv_trunc_len;
 	tfm = esp->conf.tfm;
 	blksize = (crypto_tfm_alg_blocksize(tfm) + 3) & ~3;
@@ -100,7 +75,6 @@ int esp6_output(struct sk_buff **pskb)
 		clen = (clen + esp->conf.padlen-1)&~(esp->conf.padlen-1);
 
 	if ((nfrags = skb_cow_data(*pskb, clen-(*pskb)->len+alen, &trailer)) < 0) {
-		if (!x->props.mode && iph) kfree(iph);
 		goto error;
 	}
 
@@ -113,34 +87,11 @@ int esp6_output(struct sk_buff **pskb)
 	*(u8*)(trailer->tail + clen-(*pskb)->len - 2) = (clen - (*pskb)->len)-2;
 	pskb_put(*pskb, trailer, clen - (*pskb)->len);
 
-	if (x->props.mode) {
-		iph = (*pskb)->nh.ipv6h;
-		top_iph = (struct ipv6hdr*)skb_push(*pskb, x->props.header_len);
-		esph = (struct ipv6_esp_hdr*)(top_iph+1);
-		*(u8*)(trailer->tail - 1) = IPPROTO_IPV6;
-		top_iph->version = 6;
-		top_iph->priority = iph->priority;
-		top_iph->flow_lbl[0] = iph->flow_lbl[0];
-		top_iph->flow_lbl[1] = iph->flow_lbl[1];
-		top_iph->flow_lbl[2] = iph->flow_lbl[2];
-		if (x->props.flags & XFRM_STATE_NOECN)
-			IP6_ECN_clear(top_iph);
-		top_iph->nexthdr = IPPROTO_ESP;
-		top_iph->payload_len = htons((*pskb)->len + alen - sizeof(struct ipv6hdr));
-		top_iph->hop_limit = iph->hop_limit;
-		ipv6_addr_copy(&top_iph->saddr,
-			       (struct in6_addr *)&x->props.saddr);
-		ipv6_addr_copy(&top_iph->daddr,
-			       (struct in6_addr *)&x->id.daddr);
-	} else { 
-		esph = (struct ipv6_esp_hdr*)skb_push(*pskb, x->props.header_len);
-		(*pskb)->h.raw = (unsigned char*)esph;
-		top_iph = (struct ipv6hdr*)skb_push(*pskb, hdr_len);
-		memcpy(top_iph, iph, hdr_len);
-		kfree(iph);
-		top_iph->payload_len = htons((*pskb)->len + alen - sizeof(struct ipv6hdr));
-		*(u8*)(trailer->tail - 1) = nexthdr;
-	}
+	top_iph = (struct ipv6hdr *)__skb_push(*pskb, hdr_len);
+	esph = (struct ipv6_esp_hdr *)(*pskb)->h.raw;
+	top_iph->payload_len = htons((*pskb)->len + alen - sizeof(*top_iph));
+	*(u8*)(trailer->tail - 1) = *(*pskb)->nh.raw;
+	*(*pskb)->nh.raw = IPPROTO_ESP;
 
 	esph->spi = x->id.spi;
 	esph->seq_no = htonl(++x->replay.oseq);
@@ -173,21 +124,9 @@ int esp6_output(struct sk_buff **pskb)
 		pskb_put(*pskb, trailer, alen);
 	}
 
-	(*pskb)->nh.raw = (*pskb)->data;
-
-	x->curlft.bytes += (*pskb)->len;
-	x->curlft.packets++;
-	spin_unlock_bh(&x->lock);
-	if (((*pskb)->dst = dst_pop(dst)) == NULL) {
-		err = -EHOSTUNREACH;
-		goto error_nolock;
-	}
-	return NET_XMIT_BYPASS;
+	err = 0;
 
 error:
-	spin_unlock_bh(&x->lock);
-error_nolock:
-	kfree_skb(*pskb);
 	return err;
 }
 

net/ipv6/ipcomp6.c

@@ -120,52 +120,14 @@ static int ipcomp6_output(struct sk_buff **pskb)
 	int err;
 	struct dst_entry *dst = (*pskb)->dst;
 	struct xfrm_state *x = dst->xfrm;
-	struct ipv6hdr *iph, *top_iph;
-	int hdr_len = 0;
+	struct ipv6hdr *top_iph;
+	int hdr_len;
 	struct ipv6_comp_hdr *ipch;
 	struct ipcomp_data *ipcd = x->data;
-	u8 *prevhdr;
-	u8 nexthdr = 0;
 	int plen, dlen;
 	u8 *start, *scratch = ipcd->scratch;
 
-	if ((*pskb)->ip_summed == CHECKSUM_HW) {
-		err = skb_checksum_help(pskb, 0);
-		if (err)
-			goto error_nolock;
-	}
-
-	spin_lock_bh(&x->lock);
-
-	err = xfrm_state_check(x, *pskb);
-	if (err)
-		goto error;
-
-	if (x->props.mode) {
-		err = xfrm6_tunnel_check_size(*pskb);
-		if (err)
-			goto error;
-
-		hdr_len = sizeof(struct ipv6hdr);
-		nexthdr = IPPROTO_IPV6;
-		iph = (*pskb)->nh.ipv6h;
-		top_iph = (struct ipv6hdr *)skb_push(*pskb, sizeof(struct ipv6hdr));
-		top_iph->version = 6;
-		top_iph->priority = iph->priority;
-		top_iph->flow_lbl[0] = iph->flow_lbl[0];
-		top_iph->flow_lbl[1] = iph->flow_lbl[1];
-		top_iph->flow_lbl[2] = iph->flow_lbl[2];
-		top_iph->nexthdr = IPPROTO_IPV6; /* initial */
-		top_iph->payload_len = htons((*pskb)->len - sizeof(struct ipv6hdr));
-		top_iph->hop_limit = iph->hop_limit;
-		memcpy(&top_iph->saddr, (struct in6_addr *)&x->props.saddr, sizeof(struct in6_addr));
-		memcpy(&top_iph->daddr, (struct in6_addr *)&x->id.daddr, sizeof(struct in6_addr));
-		(*pskb)->nh.raw = (*pskb)->data; /* == top_iph */
-		(*pskb)->h.raw = (*pskb)->nh.raw + hdr_len;
-	} else {
-		hdr_len = ip6_find_1stfragopt(*pskb, &prevhdr);
-		nexthdr = *prevhdr;
-	}
+	hdr_len = (*pskb)->h.raw - (*pskb)->data;
 
 	/* check whether datagram len is larger than threshold */
 	if (((*pskb)->len - hdr_len) < ipcd->threshold) {
@@ -181,7 +143,7 @@ static int ipcomp6_output(struct sk_buff **pskb)
 	/* compression */
 	plen = (*pskb)->len - hdr_len;
 	dlen = IPCOMP_SCRATCH_SIZE;
-	start = (*pskb)->data + hdr_len;
+	start = (*pskb)->h.raw;
 
 	err = crypto_comp_compress(ipcd->tfm, start, plen, scratch, &dlen);
 	if (err) {
@@ -194,39 +156,21 @@ static int ipcomp6_output(struct sk_buff **pskb)
 	pskb_trim(*pskb, hdr_len + dlen + sizeof(struct ip_comp_hdr));
 
 	/* insert ipcomp header and replace datagram */
-	top_iph = (*pskb)->nh.ipv6h;
+	top_iph = (struct ipv6hdr *)(*pskb)->data;
 
-	if (x->props.mode && (x->props.flags & XFRM_STATE_NOECN))
-		IP6_ECN_clear(top_iph);
 	top_iph->payload_len = htons((*pskb)->len - sizeof(struct ipv6hdr));
-	(*pskb)->nh.raw = (*pskb)->data; /* top_iph */
-	ip6_find_1stfragopt(*pskb, &prevhdr); 
-	*prevhdr = IPPROTO_COMP;
 
-	ipch = (struct ipv6_comp_hdr *)((unsigned char *)top_iph + hdr_len);
-	ipch->nexthdr = nexthdr;
+	ipch = (struct ipv6_comp_hdr *)start;
+	ipch->nexthdr = *(*pskb)->nh.raw;
 	ipch->flags = 0;
 	ipch->cpi = htons((u16 )ntohl(x->id.spi));
+	*(*pskb)->nh.raw = IPPROTO_COMP;
 
-	(*pskb)->h.raw = (unsigned char*)ipch;
 out_ok:
-	x->curlft.bytes += (*pskb)->len;
-	x->curlft.packets++;
-	spin_unlock_bh(&x->lock);
-
-	if (((*pskb)->dst = dst_pop(dst)) == NULL) {
-		err = -EHOSTUNREACH;
-		goto error_nolock;
-	}
-	err = NET_XMIT_BYPASS;
+	err = 0;
 
-out_exit:
-	return err;
 error:
-	spin_unlock_bh(&x->lock);
-error_nolock:
-	kfree_skb(*pskb);
-	goto out_exit;
+	return err;
 }
 
 static void ipcomp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,

net/ipv6/xfrm6_output.c

+/*
+ * xfrm6_output.c - Common IPsec encapsulation code for IPv6.
+ * Copyright (C) 2002 USAGI/WIDE Project
+ * Copyright (c) 2004 Herbert Xu <herbert@gondor.apana.org.au>
+ * 
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/skbuff.h>
+#include <linux/spinlock.h>
+#include <net/inet_ecn.h>
+#include <net/ipv6.h>
+#include <net/xfrm.h>
+
+/* Add encapsulation header.
+ *
+ * In transport mode, the IP header and mutable extension headers will be moved
+ * forward to make space for the encapsulation header.
+ *
+ * In tunnel mode, 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
+ *
+ * On exit, skb->h will be set to the start of the encapsulation header to be
+ * filled in by x->type->output and skb->nh will be set to the nextheader field
+ * of the extension header directly preceding the encapsulation header, or in
+ * its absence, that of the top IP header.  The value of skb->data will always
+ * point to the top IP header.
+ */
+static void xfrm6_encap(struct sk_buff *skb)
+{
+	struct dst_entry *dst = skb->dst;
+	struct xfrm_state *x = dst->xfrm;
+	struct ipv6hdr *iph, *top_iph;
+
+	skb_push(skb, x->props.header_len);
+	iph = skb->nh.ipv6h;
+
+	if (!x->props.mode) {
+		u8 *prevhdr;
+		int hdr_len;
+
+		hdr_len = ip6_find_1stfragopt(skb, &prevhdr);
+		skb->nh.raw = prevhdr - x->props.header_len;
+		skb->h.raw = skb->data + hdr_len;
+		memmove(skb->data, iph, hdr_len);
+		return;
+	}
+
+	skb->nh.raw = skb->data;
+	top_iph = skb->nh.ipv6h;
+	skb->nh.raw = &top_iph->nexthdr;
+	skb->h.ipv6h = top_iph + 1;
+
+	top_iph->version = 6;
+	top_iph->priority = iph->priority;
+	if (x->props.flags & XFRM_STATE_NOECN)
+		IP6_ECN_clear(top_iph);
+	top_iph->flow_lbl[0] = iph->flow_lbl[0];
+	top_iph->flow_lbl[1] = iph->flow_lbl[1];
+	top_iph->flow_lbl[2] = iph->flow_lbl[2];
+	top_iph->nexthdr = IPPROTO_IPV6; 
+	top_iph->hop_limit = iph->hop_limit;
+	ipv6_addr_copy(&top_iph->saddr, (struct in6_addr *)&x->props.saddr);
+	ipv6_addr_copy(&top_iph->daddr, (struct in6_addr *)&x->id.daddr);
+}
+
+int xfrm6_output(struct sk_buff **pskb)
+{
+	struct sk_buff *skb = *pskb;
+	struct dst_entry *dst = skb->dst;
+	struct xfrm_state *x = dst->xfrm;
+	int err;
+	
+	if (skb->ip_summed == CHECKSUM_HW) {
+		err = skb_checksum_help(pskb, 0);
+		skb = *pskb;
+		if (err)
+			goto error_nolock;
+	}
+
+	spin_lock_bh(&x->lock);
+	err = xfrm_state_check(x, skb);
+	if (err)
+		goto error;
+
+	if (x->props.mode) {
+		err = xfrm6_tunnel_check_size(skb);
+		if (err)
+			goto error;
+	}
+
+	xfrm6_encap(skb);
+
+	err = x->type->output(pskb);
+	skb = *pskb;
+	if (err)
+		goto error;
+
+	x->curlft.bytes += skb->len;
+	x->curlft.packets++;
+
+	spin_unlock_bh(&x->lock);
+
+	skb->nh.raw = skb->data;
+	
+	if (!(skb->dst = dst_pop(dst))) {
+		err = -EHOSTUNREACH;
+		goto error_nolock;
+	}
+	err = NET_XMIT_BYPASS;
+
+out_exit:
+	return err;
+error:
+	spin_unlock_bh(&x->lock);
+error_nolock:
+	kfree_skb(skb);
+	goto out_exit;
+}

net/ipv6/xfrm6_policy.c

@@ -157,7 +157,7 @@ __xfrm6_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int
 		/* Copy neighbour for reachability confirmation */
 		dst_prev->neighbour	= neigh_clone(rt->u.dst.neighbour);
 		dst_prev->input		= rt->u.dst.input;
-		dst_prev->output	= dst_prev->xfrm->type->output;
+		dst_prev->output	= xfrm6_output;
 		/* Sheit... I remember I did this right. Apparently,
 		 * it was magically lost, so this code needs audit */
 		x->u.rt6.rt6i_flags    = rt0->rt6i_flags&(RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL);

net/ipv6/xfrm6_tunnel.c

@@ -365,46 +365,12 @@ EXPORT_SYMBOL(xfrm6_tunnel_check_size);
 static int xfrm6_tunnel_output(struct sk_buff **pskb)
 {
 	struct sk_buff *skb = *pskb;
-	struct dst_entry *dst = skb->dst;
-	struct xfrm_state *x = dst->xfrm;
-	struct ipv6hdr *iph, *top_iph;
-	int err;
-
-	if ((err = xfrm6_tunnel_check_size(skb)) != 0)
-		goto error_nolock;
-
-	iph = skb->nh.ipv6h;
-
-	top_iph = (struct ipv6hdr *)skb_push(skb, x->props.header_len);
-	top_iph->version = 6;
-	top_iph->priority = iph->priority;
-	top_iph->flow_lbl[0] = iph->flow_lbl[0];
-	top_iph->flow_lbl[1] = iph->flow_lbl[1];
-	top_iph->flow_lbl[2] = iph->flow_lbl[2];
-	top_iph->nexthdr = IPPROTO_IPV6; 
-	top_iph->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
-	top_iph->hop_limit = iph->hop_limit;
-	memcpy(&top_iph->saddr, (struct in6_addr *)&x->props.saddr, sizeof(struct in6_addr));
-	memcpy(&top_iph->daddr, (struct in6_addr *)&x->id.daddr, sizeof(struct in6_addr));
-	skb->nh.raw = skb->data;
-	skb->h.raw = skb->nh.raw + sizeof(struct ipv6hdr);
-
-	x->curlft.bytes += skb->len;
-	x->curlft.packets++;
-
-	spin_unlock_bh(&x->lock);
+	struct ipv6hdr *top_iph;
 
-	if ((skb->dst = dst_pop(dst)) == NULL) { 
-		kfree_skb(skb);
-		err = -EHOSTUNREACH;
-		goto error_nolock;
-	}
-
-	return NET_XMIT_BYPASS;
+	top_iph = (struct ipv6hdr *)skb->data;
+	top_iph->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
 
-error_nolock:
-	kfree_skb(skb);
-	return err;
+	return 0;
 }
 
 static int xfrm6_tunnel_input(struct xfrm_state *x, struct xfrm_decap_state *decap, struct sk_buff *skb)