Merge branch 'dde' into upstream-merged

1 files changed, 1948 insertions, 0 deletions

diff --git a/libdde_linux26/contrib/include/linux/skbuff.h b/libdde_linux26/contrib/include/linux/skbuff.h
new file mode 100644
index 00000000..a9e9534d
--- /dev/null
+++ b/libdde_linux26/contrib/include/linux/skbuff.h
@@ -0,0 +1,1948 @@
+/*
+ *	Definitions for the 'struct sk_buff' memory handlers.
+ *
+ *	Authors:
+ *		Alan Cox, <gw4pts@gw4pts.ampr.org>
+ *		Florian La Roche, <rzsfl@rz.uni-sb.de>
+ *
+ *	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.
+ */
+
+#ifndef _LINUX_SKBUFF_H
+#define _LINUX_SKBUFF_H
+
+#include <linux/kernel.h>
+#include <linux/compiler.h>
+#include <linux/time.h>
+#include <linux/cache.h>
+
+#include <asm/atomic.h>
+#include <asm/types.h>
+#include <linux/spinlock.h>
+#include <linux/net.h>
+#include <linux/textsearch.h>
+#include <net/checksum.h>
+#include <linux/rcupdate.h>
+#include <linux/dmaengine.h>
+#include <linux/hrtimer.h>
+
+#define HAVE_ALLOC_SKB		/* For the drivers to know */
+#define HAVE_ALIGNABLE_SKB	/* Ditto 8)		   */
+
+/* Don't change this without changing skb_csum_unnecessary! */
+#define CHECKSUM_NONE 0
+#define CHECKSUM_UNNECESSARY 1
+#define CHECKSUM_COMPLETE 2
+#define CHECKSUM_PARTIAL 3
+
+#define SKB_DATA_ALIGN(X)	(((X) + (SMP_CACHE_BYTES - 1)) & \
+				 ~(SMP_CACHE_BYTES - 1))
+#define SKB_WITH_OVERHEAD(X)	\
+	((X) - SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
+#define SKB_MAX_ORDER(X, ORDER) \
+	SKB_WITH_OVERHEAD((PAGE_SIZE << (ORDER)) - (X))
+#define SKB_MAX_HEAD(X)		(SKB_MAX_ORDER((X), 0))
+#define SKB_MAX_ALLOC		(SKB_MAX_ORDER(0, 2))
+
+/* A. Checksumming of received packets by device.
+ *
+ *	NONE: device failed to checksum this packet.
+ *		skb->csum is undefined.
+ *
+ *	UNNECESSARY: device parsed packet and wouldbe verified checksum.
+ *		skb->csum is undefined.
+ *	      It is bad option, but, unfortunately, many of vendors do this.
+ *	      Apparently with secret goal to sell you new device, when you
+ *	      will add new protocol to your host. F.e. IPv6. 8)
+ *
+ *	COMPLETE: the most generic way. Device supplied checksum of _all_
+ *	    the packet as seen by netif_rx in skb->csum.
+ *	    NOTE: Even if device supports only some protocols, but
+ *	    is able to produce some skb->csum, it MUST use COMPLETE,
+ *	    not UNNECESSARY.
+ *
+ *	PARTIAL: identical to the case for output below.  This may occur
+ *	    on a packet received directly from another Linux OS, e.g.,
+ *	    a virtualised Linux kernel on the same host.  The packet can
+ *	    be treated in the same way as UNNECESSARY except that on
+ *	    output (i.e., forwarding) the checksum must be filled in
+ *	    by the OS or the hardware.
+ *
+ * B. Checksumming on output.
+ *
+ *	NONE: skb is checksummed by protocol or csum is not required.
+ *
+ *	PARTIAL: device is required to csum packet as seen by hard_start_xmit
+ *	from skb->csum_start to the end and to record the checksum
+ *	at skb->csum_start + skb->csum_offset.
+ *
+ *	Device must show its capabilities in dev->features, set
+ *	at device setup time.
+ *	NETIF_F_HW_CSUM	- it is clever device, it is able to checksum
+ *			  everything.
+ *	NETIF_F_NO_CSUM - loopback or reliable single hop media.
+ *	NETIF_F_IP_CSUM - device is dumb. It is able to csum only
+ *			  TCP/UDP over IPv4. Sigh. Vendors like this
+ *			  way by an unknown reason. Though, see comment above
+ *			  about CHECKSUM_UNNECESSARY. 8)
+ *	NETIF_F_IPV6_CSUM about as dumb as the last one but does IPv6 instead.
+ *
+ *	Any questions? No questions, good. 		--ANK
+ */
+
+struct net_device;
+struct scatterlist;
+struct pipe_inode_info;
+
+#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
+struct nf_conntrack {
+	atomic_t use;
+};
+#endif
+
+#ifdef CONFIG_BRIDGE_NETFILTER
+struct nf_bridge_info {
+	atomic_t use;
+	struct net_device *physindev;
+	struct net_device *physoutdev;
+	unsigned int mask;
+	unsigned long data[32 / sizeof(unsigned long)];
+};
+#endif
+
+struct sk_buff_head {
+	/* These two members must be first. */
+	struct sk_buff	*next;
+	struct sk_buff	*prev;
+
+	__u32		qlen;
+	spinlock_t	lock;
+};
+
+struct sk_buff;
+
+/* To allow 64K frame to be packed as single skb without frag_list */
+#define MAX_SKB_FRAGS (65536/PAGE_SIZE + 2)
+
+typedef struct skb_frag_struct skb_frag_t;
+
+struct skb_frag_struct {
+	struct page *page;
+	__u32 page_offset;
+	__u32 size;
+};
+
+/* This data is invariant across clones and lives at
+ * the end of the header data, ie. at skb->end.
+ */
+struct skb_shared_info {
+	atomic_t	dataref;
+	unsigned short	nr_frags;
+	unsigned short	gso_size;
+	/* Warning: this field is not always filled in (UFO)! */
+	unsigned short	gso_segs;
+	unsigned short  gso_type;
+	__be32          ip6_frag_id;
+#ifdef CONFIG_HAS_DMA
+	unsigned int	num_dma_maps;
+#endif
+	struct sk_buff	*frag_list;
+	skb_frag_t	frags[MAX_SKB_FRAGS];
+#ifdef CONFIG_HAS_DMA
+	dma_addr_t	dma_maps[MAX_SKB_FRAGS + 1];
+#endif
+};
+
+/* We divide dataref into two halves.  The higher 16 bits hold references
+ * to the payload part of skb->data.  The lower 16 bits hold references to
+ * the entire skb->data.  A clone of a headerless skb holds the length of
+ * the header in skb->hdr_len.
+ *
+ * All users must obey the rule that the skb->data reference count must be
+ * greater than or equal to the payload reference count.
+ *
+ * Holding a reference to the payload part means that the user does not
+ * care about modifications to the header part of skb->data.
+ */
+#define SKB_DATAREF_SHIFT 16
+#define SKB_DATAREF_MASK ((1 << SKB_DATAREF_SHIFT) - 1)
+
+
+enum {
+	SKB_FCLONE_UNAVAILABLE,
+	SKB_FCLONE_ORIG,
+	SKB_FCLONE_CLONE,
+};
+
+enum {
+	SKB_GSO_TCPV4 = 1 << 0,
+	SKB_GSO_UDP = 1 << 1,
+
+	/* This indicates the skb is from an untrusted source. */
+	SKB_GSO_DODGY = 1 << 2,
+
+	/* This indicates the tcp segment has CWR set. */
+	SKB_GSO_TCP_ECN = 1 << 3,
+
+	SKB_GSO_TCPV6 = 1 << 4,
+};
+
+#if BITS_PER_LONG > 32
+#define NET_SKBUFF_DATA_USES_OFFSET 1
+#endif
+
+#ifdef NET_SKBUFF_DATA_USES_OFFSET
+typedef unsigned int sk_buff_data_t;
+#else
+typedef unsigned char *sk_buff_data_t;
+#endif
+
+/** 
+ *	struct sk_buff - socket buffer
+ *	@next: Next buffer in list
+ *	@prev: Previous buffer in list
+ *	@sk: Socket we are owned by
+ *	@tstamp: Time we arrived
+ *	@dev: Device we arrived on/are leaving by
+ *	@transport_header: Transport layer header
+ *	@network_header: Network layer header
+ *	@mac_header: Link layer header
+ *	@dst: destination entry
+ *	@sp: the security path, used for xfrm
+ *	@cb: Control buffer. Free for use by every layer. Put private vars here
+ *	@len: Length of actual data
+ *	@data_len: Data length
+ *	@mac_len: Length of link layer header
+ *	@hdr_len: writable header length of cloned skb
+ *	@csum: Checksum (must include start/offset pair)
+ *	@csum_start: Offset from skb->head where checksumming should start
+ *	@csum_offset: Offset from csum_start where checksum should be stored
+ *	@local_df: allow local fragmentation
+ *	@cloned: Head may be cloned (check refcnt to be sure)
+ *	@nohdr: Payload reference only, must not modify header
+ *	@pkt_type: Packet class
+ *	@fclone: skbuff clone status
+ *	@ip_summed: Driver fed us an IP checksum
+ *	@priority: Packet queueing priority
+ *	@users: User count - see {datagram,tcp}.c
+ *	@protocol: Packet protocol from driver
+ *	@truesize: Buffer size 
+ *	@head: Head of buffer
+ *	@data: Data head pointer
+ *	@tail: Tail pointer
+ *	@end: End pointer
+ *	@destructor: Destruct function
+ *	@mark: Generic packet mark
+ *	@nfct: Associated connection, if any
+ *	@ipvs_property: skbuff is owned by ipvs
+ *	@peeked: this packet has been seen already, so stats have been
+ *		done for it, don't do them again
+ *	@nf_trace: netfilter packet trace flag
+ *	@nfctinfo: Relationship of this skb to the connection
+ *	@nfct_reasm: netfilter conntrack re-assembly pointer
+ *	@nf_bridge: Saved data about a bridged frame - see br_netfilter.c
+ *	@iif: ifindex of device we arrived on
+ *	@queue_mapping: Queue mapping for multiqueue devices
+ *	@tc_index: Traffic control index
+ *	@tc_verd: traffic control verdict
+ *	@ndisc_nodetype: router type (from link layer)
+ *	@do_not_encrypt: set to prevent encryption of this frame
+ *	@requeue: set to indicate that the wireless core should attempt
+ *		a software retry on this frame if we failed to
+ *		receive an ACK for it
+ *	@dma_cookie: a cookie to one of several possible DMA operations
+ *		done by skb DMA functions
+ *	@secmark: security marking
+ *	@vlan_tci: vlan tag control information
+ */
+
+struct sk_buff {
+	/* These two members must be first. */
+	struct sk_buff		*next;
+	struct sk_buff		*prev;
+
+	struct sock		*sk;
+	ktime_t			tstamp;
+	struct net_device	*dev;
+
+	union {
+		struct  dst_entry	*dst;
+		struct  rtable		*rtable;
+	};
+#ifdef CONFIG_XFRM
+	struct	sec_path	*sp;
+#endif
+	/*
+	 * This is the control buffer. It is free to use for every
+	 * layer. Please put your private variables there. If you
+	 * want to keep them across layers you have to do a skb_clone()
+	 * first. This is owned by whoever has the skb queued ATM.
+	 */
+	char			cb[48];
+
+	unsigned int		len,
+				data_len;
+	__u16			mac_len,
+				hdr_len;
+	union {
+		__wsum		csum;
+		struct {
+			__u16	csum_start;
+			__u16	csum_offset;
+		};
+	};
+	__u32			priority;
+	__u8			local_df:1,
+				cloned:1,
+				ip_summed:2,
+				nohdr:1,
+				nfctinfo:3;
+	__u8			pkt_type:3,
+				fclone:2,
+				ipvs_property:1,
+				peeked:1,
+				nf_trace:1;
+	__be16			protocol;
+
+	void			(*destructor)(struct sk_buff *skb);
+#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
+	struct nf_conntrack	*nfct;
+	struct sk_buff		*nfct_reasm;
+#endif
+#ifdef CONFIG_BRIDGE_NETFILTER
+	struct nf_bridge_info	*nf_bridge;
+#endif
+
+	int			iif;
+	__u16			queue_mapping;
+#ifdef CONFIG_NET_SCHED
+	__u16			tc_index;	/* traffic control index */
+#ifdef CONFIG_NET_CLS_ACT
+	__u16			tc_verd;	/* traffic control verdict */
+#endif
+#endif
+#ifdef CONFIG_IPV6_NDISC_NODETYPE
+	__u8			ndisc_nodetype:2;
+#endif
+#if defined(CONFIG_MAC80211) || defined(CONFIG_MAC80211_MODULE)
+	__u8			do_not_encrypt:1;
+	__u8			requeue:1;
+#endif
+	/* 0/13/14 bit hole */
+
+#ifdef CONFIG_NET_DMA
+	dma_cookie_t		dma_cookie;
+#endif
+#ifdef CONFIG_NETWORK_SECMARK
+	__u32			secmark;
+#endif
+
+	__u32			mark;
+
+	__u16			vlan_tci;
+
+	sk_buff_data_t		transport_header;
+	sk_buff_data_t		network_header;
+	sk_buff_data_t		mac_header;
+	/* These elements must be at the end, see alloc_skb() for details.  */
+	sk_buff_data_t		tail;
+	sk_buff_data_t		end;
+	unsigned char		*head,
+				*data;
+	unsigned int		truesize;
+	atomic_t		users;
+	
+#ifdef DDE_LINUX
+	void			*del_data;
+	int (*pre_del_func) (struct sk_buff *, void *);
+#endif
+};
+
+#ifdef __KERNEL__
+/*
+ *	Handling routines are only of interest to the kernel
+ */
+#include <linux/slab.h>
+
+#include <asm/system.h>
+
+#ifdef CONFIG_HAS_DMA
+#include <linux/dma-mapping.h>
+extern int skb_dma_map(struct device *dev, struct sk_buff *skb,
+		       enum dma_data_direction dir);
+extern void skb_dma_unmap(struct device *dev, struct sk_buff *skb,
+			  enum dma_data_direction dir);
+#endif
+
+extern void kfree_skb(struct sk_buff *skb);
+extern void	       __kfree_skb(struct sk_buff *skb);
+extern struct sk_buff *__alloc_skb(unsigned int size,
+				   gfp_t priority, int fclone, int node);
+static inline struct sk_buff *alloc_skb(unsigned int size,
+					gfp_t priority)
+{
+	return __alloc_skb(size, priority, 0, -1);
+}
+
+static inline struct sk_buff *alloc_skb_fclone(unsigned int size,
+					       gfp_t priority)
+{
+	return __alloc_skb(size, priority, 1, -1);
+}
+
+extern int skb_recycle_check(struct sk_buff *skb, int skb_size);
+
+extern struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src);
+extern struct sk_buff *skb_clone(struct sk_buff *skb,
+				 gfp_t priority);
+extern struct sk_buff *skb_copy(const struct sk_buff *skb,
+				gfp_t priority);
+extern struct sk_buff *pskb_copy(struct sk_buff *skb,
+				 gfp_t gfp_mask);
+extern int	       pskb_expand_head(struct sk_buff *skb,
+					int nhead, int ntail,
+					gfp_t gfp_mask);
+extern struct sk_buff *skb_realloc_headroom(struct sk_buff *skb,
+					    unsigned int headroom);
+extern struct sk_buff *skb_copy_expand(const struct sk_buff *skb,
+				       int newheadroom, int newtailroom,
+				       gfp_t priority);
+extern int	       skb_to_sgvec(struct sk_buff *skb,
+				    struct scatterlist *sg, int offset,
+				    int len);
+extern int	       skb_cow_data(struct sk_buff *skb, int tailbits,
+				    struct sk_buff **trailer);
+extern int	       skb_pad(struct sk_buff *skb, int pad);
+#define dev_kfree_skb(a)	kfree_skb(a)
+extern void	      skb_over_panic(struct sk_buff *skb, int len,
+				     void *here);
+extern void	      skb_under_panic(struct sk_buff *skb, int len,
+				      void *here);
+
+extern int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
+			int getfrag(void *from, char *to, int offset,
+			int len,int odd, struct sk_buff *skb),
+			void *from, int length);
+
+struct skb_seq_state
+{
+	__u32		lower_offset;
+	__u32		upper_offset;
+	__u32		frag_idx;
+	__u32		stepped_offset;
+	struct sk_buff	*root_skb;
+	struct sk_buff	*cur_skb;
+	__u8		*frag_data;
+};
+
+extern void	      skb_prepare_seq_read(struct sk_buff *skb,
+					   unsigned int from, unsigned int to,
+					   struct skb_seq_state *st);
+extern unsigned int   skb_seq_read(unsigned int consumed, const u8 **data,
+				   struct skb_seq_state *st);
+extern void	      skb_abort_seq_read(struct skb_seq_state *st);
+
+extern unsigned int   skb_find_text(struct sk_buff *skb, unsigned int from,
+				    unsigned int to, struct ts_config *config,
+				    struct ts_state *state);
+
+#ifdef NET_SKBUFF_DATA_USES_OFFSET
+static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
+{
+	return skb->head + skb->end;
+}
+#else
+static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
+{
+	return skb->end;
+}
+#endif
+
+/* Internal */
+#define skb_shinfo(SKB)	((struct skb_shared_info *)(skb_end_pointer(SKB)))
+
+/**
+ *	skb_queue_empty - check if a queue is empty
+ *	@list: queue head
+ *
+ *	Returns true if the queue is empty, false otherwise.
+ */
+static inline int skb_queue_empty(const struct sk_buff_head *list)
+{
+	return list->next == (struct sk_buff *)list;
+}
+
+/**
+ *	skb_queue_is_last - check if skb is the last entry in the queue
+ *	@list: queue head
+ *	@skb: buffer
+ *
+ *	Returns true if @skb is the last buffer on the list.
+ */
+static inline bool skb_queue_is_last(const struct sk_buff_head *list,
+				     const struct sk_buff *skb)
+{
+	return (skb->next == (struct sk_buff *) list);
+}
+
+/**
+ *	skb_queue_is_first - check if skb is the first entry in the queue
+ *	@list: queue head
+ *	@skb: buffer
+ *
+ *	Returns true if @skb is the first buffer on the list.
+ */
+static inline bool skb_queue_is_first(const struct sk_buff_head *list,
+				      const struct sk_buff *skb)
+{
+	return (skb->prev == (struct sk_buff *) list);
+}
+
+/**
+ *	skb_queue_next - return the next packet in the queue
+ *	@list: queue head
+ *	@skb: current buffer
+ *
+ *	Return the next packet in @list after @skb.  It is only valid to
+ *	call this if skb_queue_is_last() evaluates to false.
+ */
+static inline struct sk_buff *skb_queue_next(const struct sk_buff_head *list,
+					     const struct sk_buff *skb)
+{
+	/* This BUG_ON may seem severe, but if we just return then we
+	 * are going to dereference garbage.
+	 */
+	BUG_ON(skb_queue_is_last(list, skb));
+	return skb->next;
+}
+
+/**
+ *	skb_queue_prev - return the prev packet in the queue
+ *	@list: queue head
+ *	@skb: current buffer
+ *
+ *	Return the prev packet in @list before @skb.  It is only valid to
+ *	call this if skb_queue_is_first() evaluates to false.
+ */
+static inline struct sk_buff *skb_queue_prev(const struct sk_buff_head *list,
+					     const struct sk_buff *skb)
+{
+	/* This BUG_ON may seem severe, but if we just return then we
+	 * are going to dereference garbage.
+	 */
+	BUG_ON(skb_queue_is_first(list, skb));
+	return skb->prev;
+}
+
+/**
+ *	skb_get - reference buffer
+ *	@skb: buffer to reference
+ *
+ *	Makes another reference to a socket buffer and returns a pointer
+ *	to the buffer.
+ */
+static inline struct sk_buff *skb_get(struct sk_buff *skb)
+{
+	atomic_inc(&skb->users);
+	return skb;
+}
+
+/*
+ * If users == 1, we are the only owner and are can avoid redundant
+ * atomic change.
+ */
+
+/**
+ *	skb_cloned - is the buffer a clone
+ *	@skb: buffer to check
+ *
+ *	Returns true if the buffer was generated with skb_clone() and is
+ *	one of multiple shared copies of the buffer. Cloned buffers are
+ *	shared data so must not be written to under normal circumstances.
+ */
+static inline int skb_cloned(const struct sk_buff *skb)
+{
+	return skb->cloned &&
+	       (atomic_read(&skb_shinfo(skb)->dataref) & SKB_DATAREF_MASK) != 1;
+}
+
+/**
+ *	skb_header_cloned - is the header a clone
+ *	@skb: buffer to check
+ *
+ *	Returns true if modifying the header part of the buffer requires
+ *	the data to be copied.
+ */
+static inline int skb_header_cloned(const struct sk_buff *skb)
+{
+	int dataref;
+
+	if (!skb->cloned)
+		return 0;
+
+	dataref = atomic_read(&skb_shinfo(skb)->dataref);
+	dataref = (dataref & SKB_DATAREF_MASK) - (dataref >> SKB_DATAREF_SHIFT);
+	return dataref != 1;
+}
+
+/**
+ *	skb_header_release - release reference to header
+ *	@skb: buffer to operate on
+ *
+ *	Drop a reference to the header part of the buffer.  This is done
+ *	by acquiring a payload reference.  You must not read from the header
+ *	part of skb->data after this.
+ */
+static inline void skb_header_release(struct sk_buff *skb)
+{
+	BUG_ON(skb->nohdr);
+	skb->nohdr = 1;
+	atomic_add(1 << SKB_DATAREF_SHIFT, &skb_shinfo(skb)->dataref);
+}
+
+/**
+ *	skb_shared - is the buffer shared
+ *	@skb: buffer to check
+ *
+ *	Returns true if more than one person has a reference to this
+ *	buffer.
+ */
+static inline int skb_shared(const struct sk_buff *skb)
+{
+	return atomic_read(&skb->users) != 1;
+}
+
+/**
+ *	skb_share_check - check if buffer is shared and if so clone it
+ *	@skb: buffer to check
+ *	@pri: priority for memory allocation
+ *
+ *	If the buffer is shared the buffer is cloned and the old copy
+ *	drops a reference. A new clone with a single reference is returned.
+ *	If the buffer is not shared the original buffer is returned. When
+ *	being called from interrupt status or with spinlocks held pri must
+ *	be GFP_ATOMIC.
+ *
+ *	NULL is returned on a memory allocation failure.
+ */
+static inline struct sk_buff *skb_share_check(struct sk_buff *skb,
+					      gfp_t pri)
+{
+	might_sleep_if(pri & __GFP_WAIT);
+	if (skb_shared(skb)) {
+		struct sk_buff *nskb = skb_clone(skb, pri);
+		kfree_skb(skb);
+		skb = nskb;
+	}
+	return skb;
+}
+
+/*
+ *	Copy shared buffers into a new sk_buff. We effectively do COW on
+ *	packets to handle cases where we have a local reader and forward
+ *	and a couple of other messy ones. The normal one is tcpdumping
+ *	a packet thats being forwarded.
+ */
+
+/**
+ *	skb_unshare - make a copy of a shared buffer
+ *	@skb: buffer to check
+ *	@pri: priority for memory allocation
+ *
+ *	If the socket buffer is a clone then this function creates a new
+ *	copy of the data, drops a reference count on the old copy and returns
+ *	the new copy with the reference count at 1. If the buffer is not a clone
+ *	the original buffer is returned. When called with a spinlock held or
+ *	from interrupt state @pri must be %GFP_ATOMIC
+ *
+ *	%NULL is returned on a memory allocation failure.
+ */
+static inline struct sk_buff *skb_unshare(struct sk_buff *skb,
+					  gfp_t pri)
+{
+	might_sleep_if(pri & __GFP_WAIT);
+	if (skb_cloned(skb)) {
+		struct sk_buff *nskb = skb_copy(skb, pri);
+		kfree_skb(skb);	/* Free our shared copy */
+		skb = nskb;
+	}
+	return skb;
+}
+
+/**
+ *	skb_peek
+ *	@list_: list to peek at
+ *
+ *	Peek an &sk_buff. Unlike most other operations you _MUST_
+ *	be careful with this one. A peek leaves the buffer on the
+ *	list and someone else may run off with it. You must hold
+ *	the appropriate locks or have a private queue to do this.
+ *
+ *	Returns %NULL for an empty list or a pointer to the head element.
+ *	The reference count is not incremented and the reference is therefore
+ *	volatile. Use with caution.
+ */
+static inline struct sk_buff *skb_peek(struct sk_buff_head *list_)
+{
+	struct sk_buff *list = ((struct sk_buff *)list_)->next;
+	if (list == (struct sk_buff *)list_)
+		list = NULL;
+	return list;
+}
+
+/**
+ *	skb_peek_tail
+ *	@list_: list to peek at
+ *
+ *	Peek an &sk_buff. Unlike most other operations you _MUST_
+ *	be careful with this one. A peek leaves the buffer on the
+ *	list and someone else may run off with it. You must hold
+ *	the appropriate locks or have a private queue to do this.
+ *
+ *	Returns %NULL for an empty list or a pointer to the tail element.
+ *	The reference count is not incremented and the reference is therefore
+ *	volatile. Use with caution.
+ */
+static inline struct sk_buff *skb_peek_tail(struct sk_buff_head *list_)
+{
+	struct sk_buff *list = ((struct sk_buff *)list_)->prev;
+	if (list == (struct sk_buff *)list_)
+		list = NULL;
+	return list;
+}
+
+/**
+ *	skb_queue_len	- get queue length
+ *	@list_: list to measure
+ *
+ *	Return the length of an &sk_buff queue.
+ */
+static inline __u32 skb_queue_len(const struct sk_buff_head *list_)
+{
+	return list_->qlen;
+}
+
+/**
+ *	__skb_queue_head_init - initialize non-spinlock portions of sk_buff_head
+ *	@list: queue to initialize
+ *
+ *	This initializes only the list and queue length aspects of
+ *	an sk_buff_head object.  This allows to initialize the list
+ *	aspects of an sk_buff_head without reinitializing things like
+ *	the spinlock.  It can also be used for on-stack sk_buff_head
+ *	objects where the spinlock is known to not be used.
+ */
+static inline void __skb_queue_head_init(struct sk_buff_head *list)
+{
+	list->prev = list->next = (struct sk_buff *)list;
+	list->qlen = 0;
+}
+
+/*
+ * This function creates a split out lock class for each invocation;
+ * this is needed for now since a whole lot of users of the skb-queue
+ * infrastructure in drivers have different locking usage (in hardirq)
+ * than the networking core (in softirq only). In the long run either the
+ * network layer or drivers should need annotation to consolidate the
+ * main types of usage into 3 classes.
+ */
+static inline void skb_queue_head_init(struct sk_buff_head *list)
+{
+	spin_lock_init(&list->lock);
+	__skb_queue_head_init(list);
+}
+
+static inline void skb_queue_head_init_class(struct sk_buff_head *list,
+		struct lock_class_key *class)
+{
+	skb_queue_head_init(list);
+	lockdep_set_class(&list->lock, class);
+}
+
+/*
+ *	Insert an sk_buff on a list.
+ *
+ *	The "__skb_xxxx()" functions are the non-atomic ones that
+ *	can only be called with interrupts disabled.
+ */
+extern void        skb_insert(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list);
+static inline void __skb_insert(struct sk_buff *newsk,
+				struct sk_buff *prev, struct sk_buff *next,
+				struct sk_buff_head *list)
+{
+	newsk->next = next;
+	newsk->prev = prev;
+	next->prev  = prev->next = newsk;
+	list->qlen++;
+}
+
+static inline void __skb_queue_splice(const struct sk_buff_head *list,
+				      struct sk_buff *prev,
+				      struct sk_buff *next)
+{
+	struct sk_buff *first = list->next;
+	struct sk_buff *last = list->prev;
+
+	first->prev = prev;
+	prev->next = first;
+
+	last->next = next;
+	next->prev = last;
+}
+
+/**
+ *	skb_queue_splice - join two skb lists, this is designed for stacks
+ *	@list: the new list to add
+ *	@head: the place to add it in the first list
+ */
+static inline void skb_queue_splice(const struct sk_buff_head *list,
+				    struct sk_buff_head *head)
+{
+	if (!skb_queue_empty(list)) {
+		__skb_queue_splice(list, (struct sk_buff *) head, head->next);
+		head->qlen += list->qlen;
+	}
+}
+
+/**
+ *	skb_queue_splice - join two skb lists and reinitialise the emptied list
+ *	@list: the new list to add
+ *	@head: the place to add it in the first list
+ *
+ *	The list at @list is reinitialised
+ */
+static inline void skb_queue_splice_init(struct sk_buff_head *list,
+					 struct sk_buff_head *head)
+{
+	if (!skb_queue_empty(list)) {
+		__skb_queue_splice(list, (struct sk_buff *) head, head->next);
+		head->qlen += list->qlen;
+		__skb_queue_head_init(list);
+	}
+}
+
+/**
+ *	skb_queue_splice_tail - join two skb lists, each list being a queue
+ *	@list: the new list to add
+ *	@head: the place to add it in the first list
+ */
+static inline void skb_queue_splice_tail(const struct sk_buff_head *list,
+					 struct sk_buff_head *head)
+{
+	if (!skb_queue_empty(list)) {
+		__skb_queue_splice(list, head->prev, (struct sk_buff *) head);
+		head->qlen += list->qlen;
+	}
+}
+
+/**
+ *	skb_queue_splice_tail - join two skb lists and reinitialise the emptied list
+ *	@list: the new list to add
+ *	@head: the place to add it in the first list
+ *
+ *	Each of the lists is a queue.
+ *	The list at @list is reinitialised
+ */
+static inline void skb_queue_splice_tail_init(struct sk_buff_head *list,
+					      struct sk_buff_head *head)
+{
+	if (!skb_queue_empty(list)) {
+		__skb_queue_splice(list, head->prev, (struct sk_buff *) head);
+		head->qlen += list->qlen;
+		__skb_queue_head_init(list);
+	}
+}
+
+/**
+ *	__skb_queue_after - queue a buffer at the list head
+ *	@list: list to use
+ *	@prev: place after this buffer
+ *	@newsk: buffer to queue
+ *
+ *	Queue a buffer int the middle of a list. This function takes no locks
+ *	and you must therefore hold required locks before calling it.
+ *
+ *	A buffer cannot be placed on two lists at the same time.
+ */
+static inline void __skb_queue_after(struct sk_buff_head *list,
+				     struct sk_buff *prev,
+				     struct sk_buff *newsk)
+{
+	__skb_insert(newsk, prev, prev->next, list);
+}
+
+extern void skb_append(struct sk_buff *old, struct sk_buff *newsk,
+		       struct sk_buff_head *list);
+
+static inline void __skb_queue_before(struct sk_buff_head *list,
+				      struct sk_buff *next,
+				      struct sk_buff *newsk)
+{
+	__skb_insert(newsk, next->prev, next, list);
+}
+
+/**
+ *	__skb_queue_head - queue a buffer at the list head
+ *	@list: list to use
+ *	@newsk: buffer to queue
+ *
+ *	Queue a buffer at the start of a list. This function takes no locks
+ *	and you must therefore hold required locks before calling it.
+ *
+ *	A buffer cannot be placed on two lists at the same time.
+ */
+extern void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk);
+static inline void __skb_queue_head(struct sk_buff_head *list,
+				    struct sk_buff *newsk)
+{
+	__skb_queue_after(list, (struct sk_buff *)list, newsk);
+}
+
+/**
+ *	__skb_queue_tail - queue a buffer at the list tail
+ *	@list: list to use
+ *	@newsk: buffer to queue
+ *
+ *	Queue a buffer at the end of a list. This function takes no locks
+ *	and you must therefore hold required locks before calling it.
+ *
+ *	A buffer cannot be placed on two lists at the same time.
+ */
+extern void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk);
+static inline void __skb_queue_tail(struct sk_buff_head *list,
+				   struct sk_buff *newsk)
+{
+	__skb_queue_before(list, (struct sk_buff *)list, newsk);
+}
+
+/*
+ * remove sk_buff from list. _Must_ be called atomically, and with
+ * the list known..
+ */
+extern void	   skb_unlink(struct sk_buff *skb, struct sk_buff_head *list);
+static inline void __skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
+{
+	struct sk_buff *next, *prev;
+
+	list->qlen--;
+	next	   = skb->next;
+	prev	   = skb->prev;
+	skb->next  = skb->prev = NULL;
+	next->prev = prev;
+	prev->next = next;
+}
+
+/**
+ *	__skb_dequeue - remove from the head of the queue
+ *	@list: list to dequeue from
+ *
+ *	Remove the head of the list. This function does not take any locks
+ *	so must be used with appropriate locks held only. The head item is
+ *	returned or %NULL if the list is empty.
+ */
+extern struct sk_buff *skb_dequeue(struct sk_buff_head *list);
+static inline struct sk_buff *__skb_dequeue(struct sk_buff_head *list)
+{
+	struct sk_buff *skb = skb_peek(list);
+	if (skb)
+		__skb_unlink(skb, list);
+	return skb;
+}
+
+/**
+ *	__skb_dequeue_tail - remove from the tail of the queue
+ *	@list: list to dequeue from
+ *
+ *	Remove the tail of the list. This function does not take any locks
+ *	so must be used with appropriate locks held only. The tail item is
+ *	returned or %NULL if the list is empty.
+ */
+extern struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list);
+static inline struct sk_buff *__skb_dequeue_tail(struct sk_buff_head *list)
+{
+	struct sk_buff *skb = skb_peek_tail(list);
+	if (skb)
+		__skb_unlink(skb, list);
+	return skb;
+}
+
+
+static inline int skb_is_nonlinear(const struct sk_buff *skb)
+{
+	return skb->data_len;
+}
+
+static inline unsigned int skb_headlen(const struct sk_buff *skb)
+{
+	return skb->len - skb->data_len;
+}
+
+static inline int skb_pagelen(const struct sk_buff *skb)
+{
+	int i, len = 0;
+
+	for (i = (int)skb_shinfo(skb)->nr_frags - 1; i >= 0; i--)
+		len += skb_shinfo(skb)->frags[i].size;
+	return len + skb_headlen(skb);
+}
+
+static inline void skb_fill_page_desc(struct sk_buff *skb, int i,
+				      struct page *page, int off, int size)
+{
+	skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
+
+	frag->page		  = page;
+	frag->page_offset	  = off;
+	frag->size		  = size;
+	skb_shinfo(skb)->nr_frags = i + 1;
+}
+
+extern void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page,
+			    int off, int size);
+
+#define SKB_PAGE_ASSERT(skb) 	BUG_ON(skb_shinfo(skb)->nr_frags)
+#define SKB_FRAG_ASSERT(skb) 	BUG_ON(skb_shinfo(skb)->frag_list)
+#define SKB_LINEAR_ASSERT(skb)  BUG_ON(skb_is_nonlinear(skb))
+
+#ifdef NET_SKBUFF_DATA_USES_OFFSET
+static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
+{
+	return skb->head + skb->tail;
+}
+
+static inline void skb_reset_tail_pointer(struct sk_buff *skb)
+{
+	skb->tail = skb->data - skb->head;
+}
+
+static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
+{
+	skb_reset_tail_pointer(skb);
+	skb->tail += offset;
+}
+#else /* NET_SKBUFF_DATA_USES_OFFSET */
+static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
+{
+	return skb->tail;
+}
+
+static inline void skb_reset_tail_pointer(struct sk_buff *skb)
+{
+	skb->tail = skb->data;
+}
+
+static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
+{
+	skb->tail = skb->data + offset;
+}
+
+#endif /* NET_SKBUFF_DATA_USES_OFFSET */
+
+/*
+ *	Add data to an sk_buff
+ */
+extern unsigned char *skb_put(struct sk_buff *skb, unsigned int len);
+static inline unsigned char *__skb_put(struct sk_buff *skb, unsigned int len)
+{
+	unsigned char *tmp = skb_tail_pointer(skb);
+	SKB_LINEAR_ASSERT(skb);
+	skb->tail += len;
+	skb->len  += len;
+	return tmp;
+}
+
+extern unsigned char *skb_push(struct sk_buff *skb, unsigned int len);
+static inline unsigned char *__skb_push(struct sk_buff *skb, unsigned int len)
+{
+	skb->data -= len;
+	skb->len  += len;
+	return skb->data;
+}
+
+extern unsigned char *skb_pull(struct sk_buff *skb, unsigned int len);
+static inline unsigned char *__skb_pull(struct sk_buff *skb, unsigned int len)
+{
+	skb->len -= len;
+	BUG_ON(skb->len < skb->data_len);
+	return skb->data += len;
+}
+
+extern unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta);
+
+static inline unsigned char *__pskb_pull(struct sk_buff *skb, unsigned int len)
+{
+	if (len > skb_headlen(skb) &&
+	    !__pskb_pull_tail(skb, len - skb_headlen(skb)))
+		return NULL;
+	skb->len -= len;
+	return skb->data += len;
+}
+
+static inline unsigned char *pskb_pull(struct sk_buff *skb, unsigned int len)
+{
+	return unlikely(len > skb->len) ? NULL : __pskb_pull(skb, len);
+}
+
+static inline int pskb_may_pull(struct sk_buff *skb, unsigned int len)
+{
+	if (likely(len <= skb_headlen(skb)))
+		return 1;
+	if (unlikely(len > skb->len))
+		return 0;
+	return __pskb_pull_tail(skb, len - skb_headlen(skb)) != NULL;
+}
+
+/**
+ *	skb_headroom - bytes at buffer head
+ *	@skb: buffer to check
+ *
+ *	Return the number of bytes of free space at the head of an &sk_buff.
+ */
+static inline unsigned int skb_headroom(const struct sk_buff *skb)
+{
+	return skb->data - skb->head;
+}
+
+/**
+ *	skb_tailroom - bytes at buffer end
+ *	@skb: buffer to check
+ *
+ *	Return the number of bytes of free space at the tail of an sk_buff
+ */
+static inline int skb_tailroom(const struct sk_buff *skb)
+{
+	return skb_is_nonlinear(skb) ? 0 : skb->end - skb->tail;
+}
+
+/**
+ *	skb_reserve - adjust headroom
+ *	@skb: buffer to alter
+ *	@len: bytes to move
+ *
+ *	Increase the headroom of an empty &sk_buff by reducing the tail
+ *	room. This is only allowed for an empty buffer.
+ */
+static inline void skb_reserve(struct sk_buff *skb, int len)
+{
+	skb->data += len;
+	skb->tail += len;
+}
+
+#ifdef NET_SKBUFF_DATA_USES_OFFSET
+static inline unsigned char *skb_transport_header(const struct sk_buff *skb)
+{
+	return skb->head + skb->transport_header;
+}
+
+static inline void skb_reset_transport_header(struct sk_buff *skb)
+{
+	skb->transport_header = skb->data - skb->head;
+}
+
+static inline void skb_set_transport_header(struct sk_buff *skb,
+					    const int offset)
+{
+	skb_reset_transport_header(skb);
+	skb->transport_header += offset;
+}
+
+static inline unsigned char *skb_network_header(const struct sk_buff *skb)
+{
+	return skb->head + skb->network_header;
+}
+
+static inline void skb_reset_network_header(struct sk_buff *skb)
+{
+	skb->network_header = skb->data - skb->head;
+}
+
+static inline void skb_set_network_header(struct sk_buff *skb, const int offset)
+{
+	skb_reset_network_header(skb);
+	skb->network_header += offset;
+}
+
+static inline unsigned char *skb_mac_header(const struct sk_buff *skb)
+{
+	return skb->head + skb->mac_header;
+}
+
+static inline int skb_mac_header_was_set(const struct sk_buff *skb)
+{
+	return skb->mac_header != ~0U;
+}
+
+static inline void skb_reset_mac_header(struct sk_buff *skb)
+{
+	skb->mac_header = skb->data - skb->head;
+}
+
+static inline void skb_set_mac_header(struct sk_buff *skb, const int offset)
+{
+	skb_reset_mac_header(skb);
+	skb->mac_header += offset;
+}
+
+#else /* NET_SKBUFF_DATA_USES_OFFSET */
+
+static inline unsigned char *skb_transport_header(const struct sk_buff *skb)
+{
+	return skb->transport_header;
+}
+
+static inline void skb_reset_transport_header(struct sk_buff *skb)
+{
+	skb->transport_header = skb->data;
+}
+
+static inline void skb_set_transport_header(struct sk_buff *skb,
+					    const int offset)
+{
+	skb->transport_header = skb->data + offset;
+}
+
+static inline unsigned char *skb_network_header(const struct sk_buff *skb)
+{
+	return skb->network_header;
+}
+
+static inline void skb_reset_network_header(struct sk_buff *skb)
+{
+	skb->network_header = skb->data;
+}
+
+static inline void skb_set_network_header(struct sk_buff *skb, const int offset)
+{
+	skb->network_header = skb->data + offset;
+}
+
+static inline unsigned char *skb_mac_header(const struct sk_buff *skb)
+{
+	return skb->mac_header;
+}
+
+static inline int skb_mac_header_was_set(const struct sk_buff *skb)
+{
+	return skb->mac_header != NULL;
+}
+
+static inline void skb_reset_mac_header(struct sk_buff *skb)
+{
+	skb->mac_header = skb->data;
+}
+
+static inline void skb_set_mac_header(struct sk_buff *skb, const int offset)
+{
+	skb->mac_header = skb->data + offset;
+}
+#endif /* NET_SKBUFF_DATA_USES_OFFSET */
+
+static inline int skb_transport_offset(const struct sk_buff *skb)
+{
+	return skb_transport_header(skb) - skb->data;
+}
+
+static inline u32 skb_network_header_len(const struct sk_buff *skb)
+{
+	return skb->transport_header - skb->network_header;
+}
+
+static inline int skb_network_offset(const struct sk_buff *skb)
+{
+	return skb_network_header(skb) - skb->data;
+}
+
+/*
+ * CPUs often take a performance hit when accessing unaligned memory
+ * locations. The actual performance hit varies, it can be small if the
+ * hardware handles it or large if we have to take an exception and fix it
+ * in software.
+ *
+ * Since an ethernet header is 14 bytes network drivers often end up with
+ * the IP header at an unaligned offset. The IP header can be aligned by
+ * shifting the start of the packet by 2 bytes. Drivers should do this
+ * with:
+ *
+ * skb_reserve(NET_IP_ALIGN);
+ *
+ * The downside to this alignment of the IP header is that the DMA is now
+ * unaligned. On some architectures the cost of an unaligned DMA is high
+ * and this cost outweighs the gains made by aligning the IP header.
+ * 
+ * Since this trade off varies between architectures, we allow NET_IP_ALIGN
+ * to be overridden.
+ */
+#ifndef NET_IP_ALIGN
+#define NET_IP_ALIGN	2
+#endif
+
+/*
+ * The networking layer reserves some headroom in skb data (via
+ * dev_alloc_skb). This is used to avoid having to reallocate skb data when
+ * the header has to grow. In the default case, if the header has to grow
+ * 16 bytes or less we avoid the reallocation.
+ *
+ * Unfortunately this headroom changes the DMA alignment of the resulting
+ * network packet. As for NET_IP_ALIGN, this unaligned DMA is expensive
+ * on some architectures. An architecture can override this value,
+ * perhaps setting it to a cacheline in size (since that will maintain
+ * cacheline alignment of the DMA). It must be a power of 2.
+ *
+ * Various parts of the networking layer expect at least 16 bytes of
+ * headroom, you should not reduce this.
+ */
+#ifndef NET_SKB_PAD
+#define NET_SKB_PAD	16
+#endif
+
+extern int ___pskb_trim(struct sk_buff *skb, unsigned int len);
+
+static inline void __skb_trim(struct sk_buff *skb, unsigned int len)
+{
+	if (unlikely(skb->data_len)) {
+		WARN_ON(1);
+		return;
+	}
+	skb->len = len;
+	skb_set_tail_pointer(skb, len);
+}
+
+extern void skb_trim(struct sk_buff *skb, unsigned int len);
+
+static inline int __pskb_trim(struct sk_buff *skb, unsigned int len)
+{
+	if (skb->data_len)
+		return ___pskb_trim(skb, len);
+	__skb_trim(skb, len);
+	return 0;
+}
+
+static inline int pskb_trim(struct sk_buff *skb, unsigned int len)
+{
+	return (len < skb->len) ? __pskb_trim(skb, len) : 0;
+}
+
+/**
+ *	pskb_trim_unique - remove end from a paged unique (not cloned) buffer
+ *	@skb: buffer to alter
+ *	@len: new length
+ *
+ *	This is identical to pskb_trim except that the caller knows that
+ *	the skb is not cloned so we should never get an error due to out-
+ *	of-memory.
+ */
+static inline void pskb_trim_unique(struct sk_buff *skb, unsigned int len)
+{
+	int err = pskb_trim(skb, len);
+	BUG_ON(err);
+}
+
+/**
+ *	skb_orphan - orphan a buffer
+ *	@skb: buffer to orphan
+ *
+ *	If a buffer currently has an owner then we call the owner's
+ *	destructor function and make the @skb unowned. The buffer continues
+ *	to exist but is no longer charged to its former owner.
+ */
+static inline void skb_orphan(struct sk_buff *skb)
+{
+	if (skb->destructor)
+		skb->destructor(skb);
+	skb->destructor = NULL;
+	skb->sk		= NULL;
+}
+
+/**
+ *	__skb_queue_purge - empty a list
+ *	@list: list to empty
+ *
+ *	Delete all buffers on an &sk_buff list. Each buffer is removed from
+ *	the list and one reference dropped. This function does not take the
+ *	list lock and the caller must hold the relevant locks to use it.
+ */
+extern void skb_queue_purge(struct sk_buff_head *list);
+static inline void __skb_queue_purge(struct sk_buff_head *list)
+{
+	struct sk_buff *skb;
+	while ((skb = __skb_dequeue(list)) != NULL)
+		kfree_skb(skb);
+}
+
+/**
+ *	__dev_alloc_skb - allocate an skbuff for receiving
+ *	@length: length to allocate
+ *	@gfp_mask: get_free_pages mask, passed to alloc_skb
+ *
+ *	Allocate a new &sk_buff and assign it a usage count of one. The
+ *	buffer has unspecified headroom built in. Users should allocate
+ *	the headroom they think they need without accounting for the
+ *	built in space. The built in space is used for optimisations.
+ *
+ *	%NULL is returned if there is no free memory.
+ */
+static inline struct sk_buff *__dev_alloc_skb(unsigned int length,
+					      gfp_t gfp_mask)
+{
+	struct sk_buff *skb = alloc_skb(length + NET_SKB_PAD, gfp_mask);
+	if (likely(skb))
+		skb_reserve(skb, NET_SKB_PAD);
+	return skb;
+}
+
+extern struct sk_buff *dev_alloc_skb(unsigned int length);
+
+extern struct sk_buff *__netdev_alloc_skb(struct net_device *dev,
+		unsigned int length, gfp_t gfp_mask);
+
+/**
+ *	netdev_alloc_skb - allocate an skbuff for rx on a specific device
+ *	@dev: network device to receive on
+ *	@length: length to allocate
+ *
+ *	Allocate a new &sk_buff and assign it a usage count of one. The
+ *	buffer has unspecified headroom built in. Users should allocate
+ *	the headroom they think they need without accounting for the
+ *	built in space. The built in space is used for optimisations.
+ *
+ *	%NULL is returned if there is no free memory. Although this function
+ *	allocates memory it can be called from an interrupt.
+ */
+static inline struct sk_buff *netdev_alloc_skb(struct net_device *dev,
+		unsigned int length)
+{
+	return __netdev_alloc_skb(dev, length, GFP_ATOMIC);
+}
+
+extern struct page *__netdev_alloc_page(struct net_device *dev, gfp_t gfp_mask);
+
+/**
+ *	netdev_alloc_page - allocate a page for ps-rx on a specific device
+ *	@dev: network device to receive on
+ *
+ * 	Allocate a new page node local to the specified device.
+ *
+ * 	%NULL is returned if there is no free memory.
+ */
+static inline struct page *netdev_alloc_page(struct net_device *dev)
+{
+	return __netdev_alloc_page(dev, GFP_ATOMIC);
+}
+
+static inline void netdev_free_page(struct net_device *dev, struct page *page)
+{
+	__free_page(page);
+}
+
+/**
+ *	skb_clone_writable - is the header of a clone writable
+ *	@skb: buffer to check
+ *	@len: length up to which to write
+ *
+ *	Returns true if modifying the header part of the cloned buffer
+ *	does not requires the data to be copied.
+ */
+static inline int skb_clone_writable(struct sk_buff *skb, unsigned int len)
+{
+	return !skb_header_cloned(skb) &&
+	       skb_headroom(skb) + len <= skb->hdr_len;
+}
+
+static inline int __skb_cow(struct sk_buff *skb, unsigned int headroom,
+			    int cloned)
+{
+	int delta = 0;
+
+	if (headroom < NET_SKB_PAD)
+		headroom = NET_SKB_PAD;
+	if (headroom > skb_headroom(skb))
+		delta = headroom - skb_headroom(skb);
+
+	if (delta || cloned)
+		return pskb_expand_head(skb, ALIGN(delta, NET_SKB_PAD), 0,
+					GFP_ATOMIC);
+	return 0;
+}
+
+/**
+ *	skb_cow - copy header of skb when it is required
+ *	@skb: buffer to cow
+ *	@headroom: needed headroom
+ *
+ *	If the skb passed lacks sufficient headroom or its data part
+ *	is shared, data is reallocated. If reallocation fails, an error
+ *	is returned and original skb is not changed.
+ *
+ *	The result is skb with writable area skb->head...skb->tail
+ *	and at least @headroom of space at head.
+ */
+static inline int skb_cow(struct sk_buff *skb, unsigned int headroom)
+{
+	return __skb_cow(skb, headroom, skb_cloned(skb));
+}
+
+/**
+ *	skb_cow_head - skb_cow but only making the head writable
+ *	@skb: buffer to cow
+ *	@headroom: needed headroom
+ *
+ *	This function is identical to skb_cow except that we replace the
+ *	skb_cloned check by skb_header_cloned.  It should be used when
+ *	you only need to push on some header and do not need to modify
+ *	the data.
+ */
+static inline int skb_cow_head(struct sk_buff *skb, unsigned int headroom)
+{
+	return __skb_cow(skb, headroom, skb_header_cloned(skb));
+}
+
+/**
+ *	skb_padto	- pad an skbuff up to a minimal size
+ *	@skb: buffer to pad
+ *	@len: minimal length
+ *
+ *	Pads up a buffer to ensure the trailing bytes exist and are
+ *	blanked. If the buffer already contains sufficient data it
+ *	is untouched. Otherwise it is extended. Returns zero on
+ *	success. The skb is freed on error.
+ */
+ 
+static inline int skb_padto(struct sk_buff *skb, unsigned int len)
+{
+	unsigned int size = skb->len;
+	if (likely(size >= len))
+		return 0;
+	return skb_pad(skb, len - size);
+}
+
+static inline int skb_add_data(struct sk_buff *skb,
+			       char __user *from, int copy)
+{
+	const int off = skb->len;
+
+	if (skb->ip_summed == CHECKSUM_NONE) {
+		int err = 0;
+		__wsum csum = csum_and_copy_from_user(from, skb_put(skb, copy),
+							    copy, 0, &err);
+		if (!err) {
+			skb->csum = csum_block_add(skb->csum, csum, off);
+			return 0;
+		}
+	} else if (!copy_from_user(skb_put(skb, copy), from, copy))
+		return 0;
+
+	__skb_trim(skb, off);
+	return -EFAULT;
+}
+
+static inline int skb_can_coalesce(struct sk_buff *skb, int i,
+				   struct page *page, int off)
+{
+	if (i) {
+		struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[i - 1];
+
+		return page == frag->page &&
+		       off == frag->page_offset + frag->size;
+	}
+	return 0;
+}
+
+static inline int __skb_linearize(struct sk_buff *skb)
+{
+	return __pskb_pull_tail(skb, skb->data_len) ? 0 : -ENOMEM;
+}
+
+/**
+ *	skb_linearize - convert paged skb to linear one
+ *	@skb: buffer to linarize
+ *
+ *	If there is no free memory -ENOMEM is returned, otherwise zero
+ *	is returned and the old skb data released.
+ */
+static inline int skb_linearize(struct sk_buff *skb)
+{
+	return skb_is_nonlinear(skb) ? __skb_linearize(skb) : 0;
+}
+
+/**
+ *	skb_linearize_cow - make sure skb is linear and writable
+ *	@skb: buffer to process
+ *
+ *	If there is no free memory -ENOMEM is returned, otherwise zero
+ *	is returned and the old skb data released.
+ */
+static inline int skb_linearize_cow(struct sk_buff *skb)
+{
+	return skb_is_nonlinear(skb) || skb_cloned(skb) ?
+	       __skb_linearize(skb) : 0;
+}
+
+/**
+ *	skb_postpull_rcsum - update checksum for received skb after pull
+ *	@skb: buffer to update
+ *	@start: start of data before pull
+ *	@len: length of data pulled
+ *
+ *	After doing a pull on a received packet, you need to call this to
+ *	update the CHECKSUM_COMPLETE checksum, or set ip_summed to
+ *	CHECKSUM_NONE so that it can be recomputed from scratch.
+ */
+
+static inline void skb_postpull_rcsum(struct sk_buff *skb,
+				      const void *start, unsigned int len)
+{
+	if (skb->ip_summed == CHECKSUM_COMPLETE)
+		skb->csum = csum_sub(skb->csum, csum_partial(start, len, 0));
+}
+
+unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len);
+
+/**
+ *	pskb_trim_rcsum - trim received skb and update checksum
+ *	@skb: buffer to trim
+ *	@len: new length
+ *
+ *	This is exactly the same as pskb_trim except that it ensures the
+ *	checksum of received packets are still valid after the operation.
+ */
+
+static inline int pskb_trim_rcsum(struct sk_buff *skb, unsigned int len)
+{
+	if (likely(len >= skb->len))
+		return 0;
+	if (skb->ip_summed == CHECKSUM_COMPLETE)
+		skb->ip_summed = CHECKSUM_NONE;
+	return __pskb_trim(skb, len);
+}
+
+#define skb_queue_walk(queue, skb) \
+		for (skb = (queue)->next;					\
+		     prefetch(skb->next), (skb != (struct sk_buff *)(queue));	\
+		     skb = skb->next)
+
+#define skb_queue_walk_safe(queue, skb, tmp)					\
+		for (skb = (queue)->next, tmp = skb->next;			\
+		     skb != (struct sk_buff *)(queue);				\
+		     skb = tmp, tmp = skb->next)
+
+#define skb_queue_walk_from(queue, skb)						\
+		for (; prefetch(skb->next), (skb != (struct sk_buff *)(queue));	\
+		     skb = skb->next)
+
+#define skb_queue_walk_from_safe(queue, skb, tmp)				\
+		for (tmp = skb->next;						\
+		     skb != (struct sk_buff *)(queue);				\
+		     skb = tmp, tmp = skb->next)
+
+#define skb_queue_reverse_walk(queue, skb) \
+		for (skb = (queue)->prev;					\
+		     prefetch(skb->prev), (skb != (struct sk_buff *)(queue));	\
+		     skb = skb->prev)
+
+
+extern struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned flags,
+					   int *peeked, int *err);
+extern struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags,
+					 int noblock, int *err);
+extern unsigned int    datagram_poll(struct file *file, struct socket *sock,
+				     struct poll_table_struct *wait);
+extern int	       skb_copy_datagram_iovec(const struct sk_buff *from,
+					       int offset, struct iovec *to,
+					       int size);
+extern int	       skb_copy_and_csum_datagram_iovec(struct sk_buff *skb,
+							int hlen,
+							struct iovec *iov);
+extern int	       skb_copy_datagram_from_iovec(struct sk_buff *skb,
+						    int offset,
+						    struct iovec *from,
+						    int len);
+extern void	       skb_free_datagram(struct sock *sk, struct sk_buff *skb);
+extern int	       skb_kill_datagram(struct sock *sk, struct sk_buff *skb,
+					 unsigned int flags);
+extern __wsum	       skb_checksum(const struct sk_buff *skb, int offset,
+				    int len, __wsum csum);
+extern int	       skb_copy_bits(const struct sk_buff *skb, int offset,
+				     void *to, int len);
+extern int	       skb_store_bits(struct sk_buff *skb, int offset,
+				      const void *from, int len);
+extern __wsum	       skb_copy_and_csum_bits(const struct sk_buff *skb,
+					      int offset, u8 *to, int len,
+					      __wsum csum);
+extern int             skb_splice_bits(struct sk_buff *skb,
+						unsigned int offset,
+						struct pipe_inode_info *pipe,
+						unsigned int len,
+						unsigned int flags);
+extern void	       skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to);
+extern void	       skb_split(struct sk_buff *skb,
+				 struct sk_buff *skb1, const u32 len);
+extern int	       skb_shift(struct sk_buff *tgt, struct sk_buff *skb,
+				 int shiftlen);
+
+extern struct sk_buff *skb_segment(struct sk_buff *skb, int features);
+extern int	       skb_gro_receive(struct sk_buff **head,
+				       struct sk_buff *skb);
+
+static inline void *skb_header_pointer(const struct sk_buff *skb, int offset,
+				       int len, void *buffer)
+{
+	int hlen = skb_headlen(skb);
+
+	if (hlen - offset >= len)
+		return skb->data + offset;
+
+	if (skb_copy_bits(skb, offset, buffer, len) < 0)
+		return NULL;
+
+	return buffer;
+}
+
+static inline void skb_copy_from_linear_data(const struct sk_buff *skb,
+					     void *to,
+					     const unsigned int len)
+{
+	memcpy(to, skb->data, len);
+}
+
+static inline void skb_copy_from_linear_data_offset(const struct sk_buff *skb,
+						    const int offset, void *to,
+						    const unsigned int len)
+{
+	memcpy(to, skb->data + offset, len);
+}
+
+static inline void skb_copy_to_linear_data(struct sk_buff *skb,
+					   const void *from,
+					   const unsigned int len)
+{
+	memcpy(skb->data, from, len);
+}
+
+static inline void skb_copy_to_linear_data_offset(struct sk_buff *skb,
+						  const int offset,
+						  const void *from,
+						  const unsigned int len)
+{
+	memcpy(skb->data + offset, from, len);
+}
+
+extern void skb_init(void);
+
+/**
+ *	skb_get_timestamp - get timestamp from a skb
+ *	@skb: skb to get stamp from
+ *	@stamp: pointer to struct timeval to store stamp in
+ *
+ *	Timestamps are stored in the skb as offsets to a base timestamp.
+ *	This function converts the offset back to a struct timeval and stores
+ *	it in stamp.
+ */
+static inline void skb_get_timestamp(const struct sk_buff *skb, struct timeval *stamp)
+{
+	*stamp = ktime_to_timeval(skb->tstamp);
+}
+
+static inline void __net_timestamp(struct sk_buff *skb)
+{
+	skb->tstamp = ktime_get_real();
+}
+
+static inline ktime_t net_timedelta(ktime_t t)
+{
+	return ktime_sub(ktime_get_real(), t);
+}
+
+static inline ktime_t net_invalid_timestamp(void)
+{
+	return ktime_set(0, 0);
+}
+
+extern __sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len);
+extern __sum16 __skb_checksum_complete(struct sk_buff *skb);
+
+static inline int skb_csum_unnecessary(const struct sk_buff *skb)
+{
+	return skb->ip_summed & CHECKSUM_UNNECESSARY;
+}
+
+/**
+ *	skb_checksum_complete - Calculate checksum of an entire packet
+ *	@skb: packet to process
+ *
+ *	This function calculates the checksum over the entire packet plus
+ *	the value of skb->csum.  The latter can be used to supply the
+ *	checksum of a pseudo header as used by TCP/UDP.  It returns the
+ *	checksum.
+ *
+ *	For protocols that contain complete checksums such as ICMP/TCP/UDP,
+ *	this function can be used to verify that checksum on received
+ *	packets.  In that case the function should return zero if the
+ *	checksum is correct.  In particular, this function will return zero
+ *	if skb->ip_summed is CHECKSUM_UNNECESSARY which indicates that the
+ *	hardware has already verified the correctness of the checksum.
+ */
+static inline __sum16 skb_checksum_complete(struct sk_buff *skb)
+{
+	return skb_csum_unnecessary(skb) ?
+	       0 : __skb_checksum_complete(skb);
+}
+
+#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
+extern void nf_conntrack_destroy(struct nf_conntrack *nfct);
+static inline void nf_conntrack_put(struct nf_conntrack *nfct)
+{
+	if (nfct && atomic_dec_and_test(&nfct->use))
+		nf_conntrack_destroy(nfct);
+}
+static inline void nf_conntrack_get(struct nf_conntrack *nfct)
+{
+	if (nfct)
+		atomic_inc(&nfct->use);
+}
+static inline void nf_conntrack_get_reasm(struct sk_buff *skb)
+{
+	if (skb)
+		atomic_inc(&skb->users);
+}
+static inline void nf_conntrack_put_reasm(struct sk_buff *skb)
+{
+	if (skb)
+		kfree_skb(skb);
+}
+#endif
+#ifdef CONFIG_BRIDGE_NETFILTER
+static inline void nf_bridge_put(struct nf_bridge_info *nf_bridge)
+{
+	if (nf_bridge && atomic_dec_and_test(&nf_bridge->use))
+		kfree(nf_bridge);
+}
+static inline void nf_bridge_get(struct nf_bridge_info *nf_bridge)
+{
+	if (nf_bridge)
+		atomic_inc(&nf_bridge->use);
+}
+#endif /* CONFIG_BRIDGE_NETFILTER */
+static inline void nf_reset(struct sk_buff *skb)
+{
+#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
+	nf_conntrack_put(skb->nfct);
+	skb->nfct = NULL;
+	nf_conntrack_put_reasm(skb->nfct_reasm);
+	skb->nfct_reasm = NULL;
+#endif
+#ifdef CONFIG_BRIDGE_NETFILTER
+	nf_bridge_put(skb->nf_bridge);
+	skb->nf_bridge = NULL;
+#endif
+}
+
+/* Note: This doesn't put any conntrack and bridge info in dst. */
+static inline void __nf_copy(struct sk_buff *dst, const struct sk_buff *src)
+{
+#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
+	dst->nfct = src->nfct;
+	nf_conntrack_get(src->nfct);
+	dst->nfctinfo = src->nfctinfo;
+	dst->nfct_reasm = src->nfct_reasm;
+	nf_conntrack_get_reasm(src->nfct_reasm);
+#endif
+#ifdef CONFIG_BRIDGE_NETFILTER
+	dst->nf_bridge  = src->nf_bridge;
+	nf_bridge_get(src->nf_bridge);
+#endif
+}
+
+static inline void nf_copy(struct sk_buff *dst, const struct sk_buff *src)
+{
+#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
+	nf_conntrack_put(dst->nfct);
+	nf_conntrack_put_reasm(dst->nfct_reasm);
+#endif
+#ifdef CONFIG_BRIDGE_NETFILTER
+	nf_bridge_put(dst->nf_bridge);
+#endif
+	__nf_copy(dst, src);
+}
+
+#ifdef CONFIG_NETWORK_SECMARK
+static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
+{
+	to->secmark = from->secmark;
+}
+
+static inline void skb_init_secmark(struct sk_buff *skb)
+{
+	skb->secmark = 0;
+}
+#else
+static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
+{ }
+
+static inline void skb_init_secmark(struct sk_buff *skb)
+{ }
+#endif
+
+static inline void skb_set_queue_mapping(struct sk_buff *skb, u16 queue_mapping)
+{
+	skb->queue_mapping = queue_mapping;
+}
+
+static inline u16 skb_get_queue_mapping(struct sk_buff *skb)
+{
+	return skb->queue_mapping;
+}
+
+static inline void skb_copy_queue_mapping(struct sk_buff *to, const struct sk_buff *from)
+{
+	to->queue_mapping = from->queue_mapping;
+}
+
+#ifdef CONFIG_XFRM
+static inline struct sec_path *skb_sec_path(struct sk_buff *skb)
+{
+	return skb->sp;
+}
+#else
+static inline struct sec_path *skb_sec_path(struct sk_buff *skb)
+{
+	return NULL;
+}
+#endif
+
+static inline int skb_is_gso(const struct sk_buff *skb)
+{
+	return skb_shinfo(skb)->gso_size;
+}
+
+static inline int skb_is_gso_v6(const struct sk_buff *skb)
+{
+	return skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6;
+}
+
+extern void __skb_warn_lro_forwarding(const struct sk_buff *skb);
+
+static inline bool skb_warn_if_lro(const struct sk_buff *skb)
+{
+	/* LRO sets gso_size but not gso_type, whereas if GSO is really
+	 * wanted then gso_type will be set. */
+	struct skb_shared_info *shinfo = skb_shinfo(skb);
+	if (shinfo->gso_size != 0 && unlikely(shinfo->gso_type == 0)) {
+		__skb_warn_lro_forwarding(skb);
+		return true;
+	}
+	return false;
+}
+
+static inline void skb_forward_csum(struct sk_buff *skb)
+{
+	/* Unfortunately we don't support this one.  Any brave souls? */
+	if (skb->ip_summed == CHECKSUM_COMPLETE)
+		skb->ip_summed = CHECKSUM_NONE;
+}
+
+bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off);
+#endif	/* __KERNEL__ */
+#endif	/* _LINUX_SKBUFF_H */