1 files changed, 370 insertions, 125 deletions

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 224506a6fa8..c16615bfb61 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -62,6 +62,7 @@
 #include <linux/scatterlist.h>
 #include <linux/errqueue.h>
 #include <linux/prefetch.h>
+#include <linux/if_vlan.h>
 
 #include <net/protocol.h>
 #include <net/dst.h>
@@ -256,16 +257,16 @@ struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
 	kmemcheck_annotate_variable(shinfo->destructor_arg);
 
 	if (flags & SKB_ALLOC_FCLONE) {
-		struct sk_buff *child = skb + 1;
-		atomic_t *fclone_ref = (atomic_t *) (child + 1);
+		struct sk_buff_fclones *fclones;
 
-		kmemcheck_annotate_bitfield(child, flags1);
-		kmemcheck_annotate_bitfield(child, flags2);
+		fclones = container_of(skb, struct sk_buff_fclones, skb1);
+
+		kmemcheck_annotate_bitfield(&fclones->skb2, flags1);
 		skb->fclone = SKB_FCLONE_ORIG;
-		atomic_set(fclone_ref, 1);
+		atomic_set(&fclones->fclone_ref, 1);
 
-		child->fclone = SKB_FCLONE_UNAVAILABLE;
-		child->pfmemalloc = pfmemalloc;
+		fclones->skb2.fclone = SKB_FCLONE_FREE;
+		fclones->skb2.pfmemalloc = pfmemalloc;
 	}
 out:
 	return skb;
@@ -344,7 +345,7 @@ static void *__netdev_alloc_frag(unsigned int fragsz, gfp_t gfp_mask)
 	unsigned long flags;
 
 	local_irq_save(flags);
-	nc = &__get_cpu_var(netdev_alloc_cache);
+	nc = this_cpu_ptr(&netdev_alloc_cache);
 	if (unlikely(!nc->frag.page)) {
 refill:
 		for (order = NETDEV_FRAG_PAGE_MAX_ORDER; ;) {
@@ -359,18 +360,29 @@ refill:
 				goto end;
 		}
 		nc->frag.size = PAGE_SIZE << order;
-recycle:
-		atomic_set(&nc->frag.page->_count, NETDEV_PAGECNT_MAX_BIAS);
+		/* Even if we own the page, we do not use atomic_set().
+		 * This would break get_page_unless_zero() users.
+		 */
+		atomic_add(NETDEV_PAGECNT_MAX_BIAS - 1,
+			   &nc->frag.page->_count);
 		nc->pagecnt_bias = NETDEV_PAGECNT_MAX_BIAS;
 		nc->frag.offset = 0;
 	}
 
 	if (nc->frag.offset + fragsz > nc->frag.size) {
-		/* avoid unnecessary locked operations if possible */
-		if ((atomic_read(&nc->frag.page->_count) == nc->pagecnt_bias) ||
-		    atomic_sub_and_test(nc->pagecnt_bias, &nc->frag.page->_count))
-			goto recycle;
-		goto refill;
+		if (atomic_read(&nc->frag.page->_count) != nc->pagecnt_bias) {
+			if (!atomic_sub_and_test(nc->pagecnt_bias,
+						 &nc->frag.page->_count))
+				goto refill;
+			/* OK, page count is 0, we can safely set it */
+			atomic_set(&nc->frag.page->_count,
+				   NETDEV_PAGECNT_MAX_BIAS);
+		} else {
+			atomic_add(NETDEV_PAGECNT_MAX_BIAS - nc->pagecnt_bias,
+				   &nc->frag.page->_count);
+		}
+		nc->pagecnt_bias = NETDEV_PAGECNT_MAX_BIAS;
+		nc->frag.offset = 0;
 	}
 
 	data = page_address(nc->frag.page) + nc->frag.offset;
@@ -490,32 +502,33 @@ static void skb_free_head(struct sk_buff *skb)
 
 static void skb_release_data(struct sk_buff *skb)
 {
-	if (!skb->cloned ||
-	    !atomic_sub_return(skb->nohdr ? (1 << SKB_DATAREF_SHIFT) + 1 : 1,
-			       &skb_shinfo(skb)->dataref)) {
-		if (skb_shinfo(skb)->nr_frags) {
-			int i;
-			for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
-				skb_frag_unref(skb, i);
-		}
+	struct skb_shared_info *shinfo = skb_shinfo(skb);
+	int i;
 
-		/*
-		 * If skb buf is from userspace, we need to notify the caller
-		 * the lower device DMA has done;
-		 */
-		if (skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY) {
-			struct ubuf_info *uarg;
+	if (skb->cloned &&
+	    atomic_sub_return(skb->nohdr ? (1 << SKB_DATAREF_SHIFT) + 1 : 1,
+			      &shinfo->dataref))
+		return;
 
-			uarg = skb_shinfo(skb)->destructor_arg;
-			if (uarg->callback)
-				uarg->callback(uarg, true);
-		}
+	for (i = 0; i < shinfo->nr_frags; i++)
+		__skb_frag_unref(&shinfo->frags[i]);
 
-		if (skb_has_frag_list(skb))
-			skb_drop_fraglist(skb);
+	/*
+	 * If skb buf is from userspace, we need to notify the caller
+	 * the lower device DMA has done;
+	 */
+	if (shinfo->tx_flags & SKBTX_DEV_ZEROCOPY) {
+		struct ubuf_info *uarg;
 
-		skb_free_head(skb);
+		uarg = shinfo->destructor_arg;
+		if (uarg->callback)
+			uarg->callback(uarg, true);
 	}
+
+	if (shinfo->frag_list)
+		kfree_skb_list(shinfo->frag_list);
+
+	skb_free_head(skb);
 }
 
 /*
@@ -523,8 +536,7 @@ static void skb_release_data(struct sk_buff *skb)
  */
 static void kfree_skbmem(struct sk_buff *skb)
 {
-	struct sk_buff *other;
-	atomic_t *fclone_ref;
+	struct sk_buff_fclones *fclones;
 
 	switch (skb->fclone) {
 	case SKB_FCLONE_UNAVAILABLE:
@@ -532,22 +544,28 @@ static void kfree_skbmem(struct sk_buff *skb)
 		break;
 
 	case SKB_FCLONE_ORIG:
-		fclone_ref = (atomic_t *) (skb + 2);
-		if (atomic_dec_and_test(fclone_ref))
-			kmem_cache_free(skbuff_fclone_cache, skb);
+		fclones = container_of(skb, struct sk_buff_fclones, skb1);
+		if (atomic_dec_and_test(&fclones->fclone_ref))
+			kmem_cache_free(skbuff_fclone_cache, fclones);
 		break;
 
 	case SKB_FCLONE_CLONE:
-		fclone_ref = (atomic_t *) (skb + 1);
-		other = skb - 1;
+		fclones = container_of(skb, struct sk_buff_fclones, skb2);
 
-		/* The clone portion is available for
-		 * fast-cloning again.
+		/* Warning : We must perform the atomic_dec_and_test() before
+		 * setting skb->fclone back to SKB_FCLONE_FREE, otherwise
+		 * skb_clone() could set clone_ref to 2 before our decrement.
+		 * Anyway, if we are going to free the structure, no need to
+		 * rewrite skb->fclone.
 		 */
-		skb->fclone = SKB_FCLONE_UNAVAILABLE;
-
-		if (atomic_dec_and_test(fclone_ref))
-			kmem_cache_free(skbuff_fclone_cache, other);
+		if (atomic_dec_and_test(&fclones->fclone_ref)) {
+			kmem_cache_free(skbuff_fclone_cache, fclones);
+		} else {
+			/* The clone portion is available for
+			 * fast-cloning again.
+			 */
+			skb->fclone = SKB_FCLONE_FREE;
+		}
 		break;
 	}
 }
@@ -565,7 +583,7 @@ static void skb_release_head_state(struct sk_buff *skb)
 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
 	nf_conntrack_put(skb->nfct);
 #endif
-#ifdef CONFIG_BRIDGE_NETFILTER
+#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 	nf_bridge_put(skb->nf_bridge);
 #endif
 /* XXX: IS this still necessary? - JHS */
@@ -673,57 +691,61 @@ void consume_skb(struct sk_buff *skb)
 }
 EXPORT_SYMBOL(consume_skb);
 
+/* Make sure a field is enclosed inside headers_start/headers_end section */
+#define CHECK_SKB_FIELD(field) \
+	BUILD_BUG_ON(offsetof(struct sk_buff, field) <		\
+		     offsetof(struct sk_buff, headers_start));	\
+	BUILD_BUG_ON(offsetof(struct sk_buff, field) >		\
+		     offsetof(struct sk_buff, headers_end));	\
+
 static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
 {
 	new->tstamp		= old->tstamp;
+	/* We do not copy old->sk */
 	new->dev		= old->dev;
-	new->transport_header	= old->transport_header;
-	new->network_header	= old->network_header;
-	new->mac_header		= old->mac_header;
-	new->inner_protocol	= old->inner_protocol;
-	new->inner_transport_header = old->inner_transport_header;
-	new->inner_network_header = old->inner_network_header;
-	new->inner_mac_header = old->inner_mac_header;
+	memcpy(new->cb, old->cb, sizeof(old->cb));
 	skb_dst_copy(new, old);
-	skb_copy_hash(new, old);
-	new->ooo_okay		= old->ooo_okay;
-	new->no_fcs		= old->no_fcs;
-	new->encapsulation	= old->encapsulation;
-	new->encap_hdr_csum	= old->encap_hdr_csum;
-	new->csum_valid		= old->csum_valid;
-	new->csum_complete_sw	= old->csum_complete_sw;
 #ifdef CONFIG_XFRM
 	new->sp			= secpath_get(old->sp);
 #endif
-	memcpy(new->cb, old->cb, sizeof(old->cb));
-	new->csum		= old->csum;
-	new->ignore_df		= old->ignore_df;
-	new->pkt_type		= old->pkt_type;
-	new->ip_summed		= old->ip_summed;
-	skb_copy_queue_mapping(new, old);
-	new->priority		= old->priority;
-#if IS_ENABLED(CONFIG_IP_VS)
-	new->ipvs_property	= old->ipvs_property;
+	__nf_copy(new, old, false);
+
+	/* Note : this field could be in headers_start/headers_end section
+	 * It is not yet because we do not want to have a 16 bit hole
+	 */
+	new->queue_mapping = old->queue_mapping;
+
+	memcpy(&new->headers_start, &old->headers_start,
+	       offsetof(struct sk_buff, headers_end) -
+	       offsetof(struct sk_buff, headers_start));
+	CHECK_SKB_FIELD(protocol);
+	CHECK_SKB_FIELD(csum);
+	CHECK_SKB_FIELD(hash);
+	CHECK_SKB_FIELD(priority);
+	CHECK_SKB_FIELD(skb_iif);
+	CHECK_SKB_FIELD(vlan_proto);
+	CHECK_SKB_FIELD(vlan_tci);
+	CHECK_SKB_FIELD(transport_header);
+	CHECK_SKB_FIELD(network_header);
+	CHECK_SKB_FIELD(mac_header);
+	CHECK_SKB_FIELD(inner_protocol);
+	CHECK_SKB_FIELD(inner_transport_header);
+	CHECK_SKB_FIELD(inner_network_header);
+	CHECK_SKB_FIELD(inner_mac_header);
+	CHECK_SKB_FIELD(mark);
+#ifdef CONFIG_NETWORK_SECMARK
+	CHECK_SKB_FIELD(secmark);
+#endif
+#ifdef CONFIG_NET_RX_BUSY_POLL
+	CHECK_SKB_FIELD(napi_id);
 #endif
-	new->pfmemalloc		= old->pfmemalloc;
-	new->protocol		= old->protocol;
-	new->mark		= old->mark;
-	new->skb_iif		= old->skb_iif;
-	__nf_copy(new, old);
 #ifdef CONFIG_NET_SCHED
-	new->tc_index		= old->tc_index;
+	CHECK_SKB_FIELD(tc_index);
 #ifdef CONFIG_NET_CLS_ACT
-	new->tc_verd		= old->tc_verd;
+	CHECK_SKB_FIELD(tc_verd);
 #endif
 #endif
-	new->vlan_proto		= old->vlan_proto;
-	new->vlan_tci		= old->vlan_tci;
-
-	skb_copy_secmark(new, old);
 
-#ifdef CONFIG_NET_RX_BUSY_POLL
-	new->napi_id	= old->napi_id;
-#endif
 }
 
 /*
@@ -854,17 +876,22 @@ EXPORT_SYMBOL_GPL(skb_copy_ubufs);
 
 struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t gfp_mask)
 {
-	struct sk_buff *n;
+	struct sk_buff_fclones *fclones = container_of(skb,
+						       struct sk_buff_fclones,
+						       skb1);
+	struct sk_buff *n = &fclones->skb2;
 
 	if (skb_orphan_frags(skb, gfp_mask))
 		return NULL;
 
-	n = skb + 1;
 	if (skb->fclone == SKB_FCLONE_ORIG &&
-	    n->fclone == SKB_FCLONE_UNAVAILABLE) {
-		atomic_t *fclone_ref = (atomic_t *) (n + 1);
+	    n->fclone == SKB_FCLONE_FREE) {
 		n->fclone = SKB_FCLONE_CLONE;
-		atomic_inc(fclone_ref);
+		/* As our fastclone was free, clone_ref must be 1 at this point.
+		 * We could use atomic_inc() here, but it is faster
+		 * to set the final value.
+		 */
+		atomic_set(&fclones->fclone_ref, 2);
 	} else {
 		if (skb_pfmemalloc(skb))
 			gfp_mask |= __GFP_MEMALLOC;
@@ -874,7 +901,6 @@ struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t gfp_mask)
 			return NULL;
 
 		kmemcheck_annotate_bitfield(n, flags1);
-		kmemcheck_annotate_bitfield(n, flags2);
 		n->fclone = SKB_FCLONE_UNAVAILABLE;
 	}
 
@@ -2646,7 +2672,7 @@ EXPORT_SYMBOL(skb_prepare_seq_read);
  * skb_seq_read() will return the remaining part of the block.
  *
  * Note 1: The size of each block of data returned can be arbitrary,
- *       this limitation is the cost for zerocopy seqeuental
+ *       this limitation is the cost for zerocopy sequential
  *       reads of potentially non linear data.
  *
  * Note 2: Fragment lists within fragments are not implemented
@@ -2780,7 +2806,7 @@ EXPORT_SYMBOL(skb_find_text);
 /**
  * skb_append_datato_frags - append the user data to a skb
  * @sk: sock  structure
- * @skb: skb structure to be appened with user data.
+ * @skb: skb structure to be appended with user data.
  * @getfrag: call back function to be used for getting the user data
  * @from: pointer to user message iov
  * @length: length of the iov message
@@ -3068,6 +3094,11 @@ perform_csum_check:
 		}
 	} while ((offset += len) < head_skb->len);
 
+	/* Some callers want to get the end of the list.
+	 * Put it in segs->prev to avoid walking the list.
+	 * (see validate_xmit_skb_list() for example)
+	 */
+	segs->prev = tail;
 	return segs;
 
 err:
@@ -3151,6 +3182,9 @@ int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb)
 		NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE_STOLEN_HEAD;
 		goto done;
 	}
+	/* switch back to head shinfo */
+	pinfo = skb_shinfo(p);
+
 	if (pinfo->frag_list)
 		goto merge;
 	if (skb_gro_len(p) != pinfo->gso_size)
@@ -3178,7 +3212,7 @@ int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb)
 	skb_shinfo(nskb)->frag_list = p;
 	skb_shinfo(nskb)->gso_size = pinfo->gso_size;
 	pinfo->gso_size = 0;
-	skb_header_release(p);
+	__skb_header_release(p);
 	NAPI_GRO_CB(nskb)->last = p;
 
 	nskb->data_len += p->len;
@@ -3210,7 +3244,7 @@ merge:
 	else
 		NAPI_GRO_CB(p)->last->next = skb;
 	NAPI_GRO_CB(p)->last = skb;
-	skb_header_release(skb);
+	__skb_header_release(skb);
 	lp = p;
 
 done:
@@ -3226,7 +3260,6 @@ done:
 	NAPI_GRO_CB(skb)->same_flow = 1;
 	return 0;
 }
-EXPORT_SYMBOL_GPL(skb_gro_receive);
 
 void __init skb_init(void)
 {
@@ -3236,8 +3269,7 @@ void __init skb_init(void)
 					      SLAB_HWCACHE_ALIGN|SLAB_PANIC,
 					      NULL);
 	skbuff_fclone_cache = kmem_cache_create("skbuff_fclone_cache",
-						(2*sizeof(struct sk_buff)) +
-						sizeof(atomic_t),
+						sizeof(struct sk_buff_fclones),
 						0,
 						SLAB_HWCACHE_ALIGN|SLAB_PANIC,
 						NULL);
@@ -3490,32 +3522,66 @@ int sock_queue_err_skb(struct sock *sk, struct sk_buff *skb)
 }
 EXPORT_SYMBOL(sock_queue_err_skb);
 
-void __skb_tstamp_tx(struct sk_buff *orig_skb,
-		     struct skb_shared_hwtstamps *hwtstamps,
-		     struct sock *sk, int tstype)
+struct sk_buff *sock_dequeue_err_skb(struct sock *sk)
 {
-	struct sock_exterr_skb *serr;
-	struct sk_buff *skb;
-	int err;
+	struct sk_buff_head *q = &sk->sk_error_queue;
+	struct sk_buff *skb, *skb_next;
+	int err = 0;
 
-	if (!sk)
-		return;
+	spin_lock_bh(&q->lock);
+	skb = __skb_dequeue(q);
+	if (skb && (skb_next = skb_peek(q)))
+		err = SKB_EXT_ERR(skb_next)->ee.ee_errno;
+	spin_unlock_bh(&q->lock);
 
-	if (hwtstamps) {
-		*skb_hwtstamps(orig_skb) =
-			*hwtstamps;
-	} else {
-		/*
-		 * no hardware time stamps available,
-		 * so keep the shared tx_flags and only
-		 * store software time stamp
-		 */
-		orig_skb->tstamp = ktime_get_real();
+	sk->sk_err = err;
+	if (err)
+		sk->sk_error_report(sk);
+
+	return skb;
+}
+EXPORT_SYMBOL(sock_dequeue_err_skb);
+
+/**
+ * skb_clone_sk - create clone of skb, and take reference to socket
+ * @skb: the skb to clone
+ *
+ * This function creates a clone of a buffer that holds a reference on
+ * sk_refcnt.  Buffers created via this function are meant to be
+ * returned using sock_queue_err_skb, or free via kfree_skb.
+ *
+ * When passing buffers allocated with this function to sock_queue_err_skb
+ * it is necessary to wrap the call with sock_hold/sock_put in order to
+ * prevent the socket from being released prior to being enqueued on
+ * the sk_error_queue.
+ */
+struct sk_buff *skb_clone_sk(struct sk_buff *skb)
+{
+	struct sock *sk = skb->sk;
+	struct sk_buff *clone;
+
+	if (!sk || !atomic_inc_not_zero(&sk->sk_refcnt))
+		return NULL;
+
+	clone = skb_clone(skb, GFP_ATOMIC);
+	if (!clone) {
+		sock_put(sk);
+		return NULL;
 	}
 
-	skb = skb_clone(orig_skb, GFP_ATOMIC);
-	if (!skb)
-		return;
+	clone->sk = sk;
+	clone->destructor = sock_efree;
+
+	return clone;
+}
+EXPORT_SYMBOL(skb_clone_sk);
+
+static void __skb_complete_tx_timestamp(struct sk_buff *skb,
+					struct sock *sk,
+					int tstype)
+{
+	struct sock_exterr_skb *serr;
+	int err;
 
 	serr = SKB_EXT_ERR(skb);
 	memset(serr, 0, sizeof(*serr));
@@ -3533,6 +3599,42 @@ void __skb_tstamp_tx(struct sk_buff *orig_skb,
 	if (err)
 		kfree_skb(skb);
 }
+
+void skb_complete_tx_timestamp(struct sk_buff *skb,
+			       struct skb_shared_hwtstamps *hwtstamps)
+{
+	struct sock *sk = skb->sk;
+
+	/* take a reference to prevent skb_orphan() from freeing the socket */
+	sock_hold(sk);
+
+	*skb_hwtstamps(skb) = *hwtstamps;
+	__skb_complete_tx_timestamp(skb, sk, SCM_TSTAMP_SND);
+
+	sock_put(sk);
+}
+EXPORT_SYMBOL_GPL(skb_complete_tx_timestamp);
+
+void __skb_tstamp_tx(struct sk_buff *orig_skb,
+		     struct skb_shared_hwtstamps *hwtstamps,
+		     struct sock *sk, int tstype)
+{
+	struct sk_buff *skb;
+
+	if (!sk)
+		return;
+
+	if (hwtstamps)
+		*skb_hwtstamps(orig_skb) = *hwtstamps;
+	else
+		orig_skb->tstamp = ktime_get_real();
+
+	skb = skb_clone(orig_skb, GFP_ATOMIC);
+	if (!skb)
+		return;
+
+	__skb_complete_tx_timestamp(skb, sk, tstype);
+}
 EXPORT_SYMBOL_GPL(__skb_tstamp_tx);
 
 void skb_tstamp_tx(struct sk_buff *orig_skb,
@@ -3557,9 +3659,14 @@ void skb_complete_wifi_ack(struct sk_buff *skb, bool acked)
 	serr->ee.ee_errno = ENOMSG;
 	serr->ee.ee_origin = SO_EE_ORIGIN_TXSTATUS;
 
+	/* take a reference to prevent skb_orphan() from freeing the socket */
+	sock_hold(sk);
+
 	err = sock_queue_err_skb(sk, skb);
 	if (err)
 		kfree_skb(skb);
+
+	sock_put(sk);
 }
 EXPORT_SYMBOL_GPL(skb_complete_wifi_ack);
 
@@ -3860,7 +3967,8 @@ bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from,
 		return false;
 
 	if (len <= skb_tailroom(to)) {
-		BUG_ON(skb_copy_bits(from, 0, skb_put(to, len), len));
+		if (len)
+			BUG_ON(skb_copy_bits(from, 0, skb_put(to, len), len));
 		*delta_truesize = 0;
 		return true;
 	}
@@ -3962,14 +4070,151 @@ EXPORT_SYMBOL_GPL(skb_scrub_packet);
 unsigned int skb_gso_transport_seglen(const struct sk_buff *skb)
 {
 	const struct skb_shared_info *shinfo = skb_shinfo(skb);
+	unsigned int thlen = 0;
 
-	if (likely(shinfo->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6)))
-		return tcp_hdrlen(skb) + shinfo->gso_size;
+	if (skb->encapsulation) {
+		thlen = skb_inner_transport_header(skb) -
+			skb_transport_header(skb);
 
+		if (likely(shinfo->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6)))
+			thlen += inner_tcp_hdrlen(skb);
+	} else if (likely(shinfo->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))) {
+		thlen = tcp_hdrlen(skb);
+	}
 	/* UFO sets gso_size to the size of the fragmentation
 	 * payload, i.e. the size of the L4 (UDP) header is already
 	 * accounted for.
 	 */
-	return shinfo->gso_size;
+	return thlen + shinfo->gso_size;
 }
 EXPORT_SYMBOL_GPL(skb_gso_transport_seglen);
+
+static struct sk_buff *skb_reorder_vlan_header(struct sk_buff *skb)
+{
+	if (skb_cow(skb, skb_headroom(skb)) < 0) {
+		kfree_skb(skb);
+		return NULL;
+	}
+
+	memmove(skb->data - ETH_HLEN, skb->data - VLAN_ETH_HLEN, 2 * ETH_ALEN);
+	skb->mac_header += VLAN_HLEN;
+	return skb;
+}
+
+struct sk_buff *skb_vlan_untag(struct sk_buff *skb)
+{
+	struct vlan_hdr *vhdr;
+	u16 vlan_tci;
+
+	if (unlikely(vlan_tx_tag_present(skb))) {
+		/* vlan_tci is already set-up so leave this for another time */
+		return skb;
+	}
+
+	skb = skb_share_check(skb, GFP_ATOMIC);
+	if (unlikely(!skb))
+		goto err_free;
+
+	if (unlikely(!pskb_may_pull(skb, VLAN_HLEN)))
+		goto err_free;
+
+	vhdr = (struct vlan_hdr *)skb->data;
+	vlan_tci = ntohs(vhdr->h_vlan_TCI);
+	__vlan_hwaccel_put_tag(skb, skb->protocol, vlan_tci);
+
+	skb_pull_rcsum(skb, VLAN_HLEN);
+	vlan_set_encap_proto(skb, vhdr);
+
+	skb = skb_reorder_vlan_header(skb);
+	if (unlikely(!skb))
+		goto err_free;
+
+	skb_reset_network_header(skb);
+	skb_reset_transport_header(skb);
+	skb_reset_mac_len(skb);
+
+	return skb;
+
+err_free:
+	kfree_skb(skb);
+	return NULL;
+}
+EXPORT_SYMBOL(skb_vlan_untag);
+
+/**
+ * alloc_skb_with_frags - allocate skb with page frags
+ *
+ * @header_len: size of linear part
+ * @data_len: needed length in frags
+ * @max_page_order: max page order desired.
+ * @errcode: pointer to error code if any
+ * @gfp_mask: allocation mask
+ *
+ * This can be used to allocate a paged skb, given a maximal order for frags.
+ */
+struct sk_buff *alloc_skb_with_frags(unsigned long header_len,
+				     unsigned long data_len,
+				     int max_page_order,
+				     int *errcode,
+				     gfp_t gfp_mask)
+{
+	int npages = (data_len + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
+	unsigned long chunk;
+	struct sk_buff *skb;
+	struct page *page;
+	gfp_t gfp_head;
+	int i;
+
+	*errcode = -EMSGSIZE;
+	/* Note this test could be relaxed, if we succeed to allocate
+	 * high order pages...
+	 */
+	if (npages > MAX_SKB_FRAGS)
+		return NULL;
+
+	gfp_head = gfp_mask;
+	if (gfp_head & __GFP_WAIT)
+		gfp_head |= __GFP_REPEAT;
+
+	*errcode = -ENOBUFS;
+	skb = alloc_skb(header_len, gfp_head);
+	if (!skb)
+		return NULL;
+
+	skb->truesize += npages << PAGE_SHIFT;
+
+	for (i = 0; npages > 0; i++) {
+		int order = max_page_order;
+
+		while (order) {
+			if (npages >= 1 << order) {
+				page = alloc_pages(gfp_mask |
+						   __GFP_COMP |
+						   __GFP_NOWARN |
+						   __GFP_NORETRY,
+						   order);
+				if (page)
+					goto fill_page;
+				/* Do not retry other high order allocations */
+				order = 1;
+				max_page_order = 0;
+			}
+			order--;
+		}
+		page = alloc_page(gfp_mask);
+		if (!page)
+			goto failure;
+fill_page:
+		chunk = min_t(unsigned long, data_len,
+			      PAGE_SIZE << order);
+		skb_fill_page_desc(skb, i, page, 0, chunk);
+		data_len -= chunk;
+		npages -= 1 << order;
+	}
+	return skb;
+
+failure:
+	kfree_skb(skb);
+	return NULL;
+}
+EXPORT_SYMBOL(alloc_skb_with_frags);