/*
   *	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/kmemcheck.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>

  /* 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;

  #if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)

  	__u32 page_offset;
  	__u32 size;

  #else
  	__u16 page_offset;
  	__u16 size;
  #endif

  };

  #define HAVE_HW_TIME_STAMP
  
  /**

   * struct skb_shared_hwtstamps - hardware time stamps

   * @hwtstamp:	hardware time stamp transformed into duration
   *		since arbitrary point in time
   * @syststamp:	hwtstamp transformed to system time base
   *
   * Software time stamps generated by ktime_get_real() are stored in
   * skb->tstamp. The relation between the different kinds of time
   * stamps is as follows:
   *
   * syststamp and tstamp can be compared against each other in
   * arbitrary combinations.  The accuracy of a
   * syststamp/tstamp/"syststamp from other device" comparison is
   * limited by the accuracy of the transformation into system time
   * base. This depends on the device driver and its underlying
   * hardware.
   *
   * hwtstamps can only be compared against other hwtstamps from
   * the same device.
   *
   * This structure is attached to packets as part of the
   * &skb_shared_info. Use skb_hwtstamps() to get a pointer.
   */
  struct skb_shared_hwtstamps {
  	ktime_t	hwtstamp;
  	ktime_t	syststamp;
  };

  /* Definitions for tx_flags in struct skb_shared_info */
  enum {
  	/* generate hardware time stamp */
  	SKBTX_HW_TSTAMP = 1 << 0,
  
  	/* generate software time stamp */
  	SKBTX_SW_TSTAMP = 1 << 1,
  
  	/* device driver is going to provide hardware time stamp */
  	SKBTX_IN_PROGRESS = 1 << 2,
  
  	/* ensure the originating sk reference is available on driver level */
  	SKBTX_DRV_NEEDS_SK_REF = 1 << 3,

  };

  /* This data is invariant across clones and lives at
   * the end of the header data, ie. at skb->end.
   */
  struct skb_shared_info {

  	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;

  	__u8		tx_flags;

  	struct sk_buff	*frag_list;

  	struct skb_shared_hwtstamps hwtstamps;

  
  	/*
  	 * Warning : all fields before dataref are cleared in __alloc_skb()
  	 */
  	atomic_t	dataref;

  	/* Intermediate layers must ensure that destructor_arg
  	 * remains valid until skb destructor */
  	void *		destructor_arg;

  	/* must be last field, see pskb_expand_head() */
  	skb_frag_t	frags[MAX_SKB_FRAGS];

  };
  
  /* 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,

  
  	SKB_GSO_FCOE = 1 << 5,

  };

  #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

  #if defined(CONFIG_NF_DEFRAG_IPV4) || defined(CONFIG_NF_DEFRAG_IPV4_MODULE) || \
      defined(CONFIG_NF_DEFRAG_IPV6) || defined(CONFIG_NF_DEFRAG_IPV6_MODULE)
  #define NET_SKBUFF_NF_DEFRAG_NEEDED 1
  #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

   *	@_skb_refdst: destination entry (with norefcount bit)

   *	@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

   *	@skb_iif: ifindex of device we arrived on

   *	@rxhash: the packet hash computed on receive

   *	@queue_mapping: Queue mapping for multiqueue devices

   *	@tc_index: Traffic control index
   *	@tc_verd: traffic control verdict

   *	@ndisc_nodetype: router type (from link layer)

   *	@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;

  	ktime_t			tstamp;

  
  	struct sock		*sk;

  	struct net_device	*dev;

  	/*
  	 * 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] __aligned(8);

  	unsigned long		_skb_refdst;

  #ifdef CONFIG_XFRM
  	struct	sec_path	*sp;
  #endif

  	unsigned int		len,

  				data_len;
  	__u16			mac_len,
  				hdr_len;

  	union {
  		__wsum		csum;

  		struct {
  			__u16	csum_start;
  			__u16	csum_offset;
  		};

  	};

  	__u32			priority;

  	kmemcheck_bitfield_begin(flags1);

  	__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;

  	kmemcheck_bitfield_end(flags1);

  	__be16			protocol;

  
  	void			(*destructor)(struct sk_buff *skb);

  #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)

  	struct nf_conntrack	*nfct;

  #endif
  #ifdef NET_SKBUFF_NF_DEFRAG_NEEDED

  	struct sk_buff		*nfct_reasm;
  #endif

  #ifdef CONFIG_BRIDGE_NETFILTER
  	struct nf_bridge_info	*nf_bridge;
  #endif

  	int			skb_iif;

  #ifdef CONFIG_NET_SCHED

  	__u16			tc_index;	/* traffic control index */

  #ifdef CONFIG_NET_CLS_ACT

  	__u16			tc_verd;	/* traffic control verdict */

  #endif

  #endif

  	__u32			rxhash;

  	kmemcheck_bitfield_begin(flags2);

  	__u16			queue_mapping:16;

  #ifdef CONFIG_IPV6_NDISC_NODETYPE

  	__u8			ndisc_nodetype:2,
  				deliver_no_wcard:1;
  #else
  	__u8			deliver_no_wcard:1;

  #endif

  	__u8			ooo_okay:1;

  	kmemcheck_bitfield_end(flags2);

  	/* 0/13 bit hole */

  #ifdef CONFIG_NET_DMA
  	dma_cookie_t		dma_cookie;
  #endif

  #ifdef CONFIG_NETWORK_SECMARK
  	__u32			secmark;
  #endif

  	union {
  		__u32		mark;
  		__u32		dropcount;
  	};

  	__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 __KERNEL__
  /*
   *	Handling routines are only of interest to the kernel
   */
  #include <linux/slab.h>
  
  #include <asm/system.h>

  /*
   * skb might have a dst pointer attached, refcounted or not.
   * _skb_refdst low order bit is set if refcount was _not_ taken
   */
  #define SKB_DST_NOREF	1UL
  #define SKB_DST_PTRMASK	~(SKB_DST_NOREF)
  
  /**
   * skb_dst - returns skb dst_entry
   * @skb: buffer
   *
   * Returns skb dst_entry, regardless of reference taken or not.
   */

  static inline struct dst_entry *skb_dst(const struct sk_buff *skb)
  {

  	/* If refdst was not refcounted, check we still are in a 
  	 * rcu_read_lock section
  	 */
  	WARN_ON((skb->_skb_refdst & SKB_DST_NOREF) &&
  		!rcu_read_lock_held() &&
  		!rcu_read_lock_bh_held());
  	return (struct dst_entry *)(skb->_skb_refdst & SKB_DST_PTRMASK);

  }

  /**
   * skb_dst_set - sets skb dst
   * @skb: buffer
   * @dst: dst entry
   *
   * Sets skb dst, assuming a reference was taken on dst and should
   * be released by skb_dst_drop()
   */

  static inline void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst)
  {

  	skb->_skb_refdst = (unsigned long)dst;
  }

  extern void skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst);

  
  /**
   * skb_dst_is_noref - Test if skb dst isnt refcounted
   * @skb: buffer
   */
  static inline bool skb_dst_is_noref(const struct sk_buff *skb)
  {
  	return (skb->_skb_refdst & SKB_DST_NOREF) && skb_dst(skb);

  }

  static inline struct rtable *skb_rtable(const struct sk_buff *skb)
  {

  	return (struct rtable *)skb_dst(skb);

  }

  extern void kfree_skb(struct sk_buff *skb);

  extern void consume_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, NUMA_NO_NODE);

  }
  
  static inline struct sk_buff *alloc_skb_fclone(unsigned int size,

  					       gfp_t priority)

  {

  	return __alloc_skb(size, priority, 1, NUMA_NO_NODE);

  }

  extern bool 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)	consume_skb(a)

  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);

  extern __u32 __skb_get_rxhash(struct sk_buff *skb);
  static inline __u32 skb_get_rxhash(struct sk_buff *skb)
  {
  	if (!skb->rxhash)
  		skb->rxhash = __skb_get_rxhash(skb);
  
  	return skb->rxhash;
  }

  #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)))

  static inline struct skb_shared_hwtstamps *skb_hwtstamps(struct sk_buff *skb)
  {
  	return &skb_shinfo(skb)->hwtstamps;
  }

  /**
   *	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 - peek at the head of an &sk_buff_head

   *	@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 - peek at the tail of an &sk_buff_head

   *	@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_has_frag_list(skb))

  #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;
  }

  static inline unsigned char *skb_pull_inline(struct sk_buff *skb, unsigned int len)
  {
  	return unlikely(len > skb->len) ? NULL : __skb_pull(skb, 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_checksum_start_offset(const struct sk_buff *skb)
  {
  	return skb->csum_start - skb_headroom(skb);
  }

  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;
  }

  static inline int pskb_network_may_pull(struct sk_buff *skb, unsigned int len)
  {
  	return pskb_may_pull(skb, skb_network_offset(skb) + len);
  }

  /*
   * 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(skb, 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

   * 32 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 32 bytes of

   * headroom, you should not reduce this.

   *
   * Using max(32, L1_CACHE_BYTES) makes sense (especially with RPS)
   * to reduce average number of cache lines per packet.
   * get_rps_cpus() for example only access one 64 bytes aligned block :

   * NET_IP_ALIGN(2) + ethernet_header(14) + IP_header(20/40) + ports(8)

   */
  #ifndef NET_SKB_PAD

  #define NET_SKB_PAD	max(32, L1_CACHE_BYTES)

  #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);
  }

  static inline struct sk_buff *netdev_alloc_skb_ip_align(struct net_device *dev,
  		unsigned int length)
  {
  	struct sk_buff *skb = netdev_alloc_skb(dev, length + NET_IP_ALIGN);
  
  	if (NET_IP_ALIGN && skb)
  		skb_reserve(skb, NET_IP_ALIGN);
  	return skb;
  }

  /**
   *	__netdev_alloc_page - allocate a page for ps-rx on a specific device
   *	@dev: network device to receive on
   *	@gfp_mask: alloc_pages_node mask
   *
   * 	Allocate a new page. dev currently unused.
   *
   * 	%NULL is returned if there is no free memory.
   */
  static inline struct page *__netdev_alloc_page(struct net_device *dev, gfp_t gfp_mask)
  {
  	return alloc_pages_node(NUMA_NO_NODE, gfp_mask, 0);
  }

  
  /**
   *	netdev_alloc_page - allocate a page for ps-rx on a specific device
   *	@dev: network device to receive on
   *

   * 	Allocate a new page. dev currently unused.

   *
   * 	%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)

  static inline bool skb_has_frag_list(const struct sk_buff *skb)

  {
  	return skb_shinfo(skb)->frag_list != NULL;
  }
  
  static inline void skb_frag_list_init(struct sk_buff *skb)
  {
  	skb_shinfo(skb)->frag_list = NULL;
  }
  
  static inline void skb_frag_add_head(struct sk_buff *skb, struct sk_buff *frag)
  {
  	frag->next = skb_shinfo(skb)->frag_list;
  	skb_shinfo(skb)->frag_list = frag;
  }
  
  #define skb_walk_frags(skb, iter)	\
  	for (iter = skb_shinfo(skb)->frag_list; iter; iter = iter->next)

  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,

  						    const struct iovec *from,
  						    int from_offset,

  						    int len);

  extern int	       skb_copy_datagram_const_iovec(const struct sk_buff *from,
  						     int offset,
  						     const struct iovec *to,
  						     int to_offset,
  						     int size);

  extern void	       skb_free_datagram(struct sock *sk, struct sk_buff *skb);

  extern void	       skb_free_datagram_locked(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);

  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);

  static inline ktime_t skb_get_ktime(const struct sk_buff *skb)
  {
  	return skb->tstamp;
  }

  /**
   *	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 skb_get_timestampns(const struct sk_buff *skb,
  				       struct timespec *stamp)
  {
  	*stamp = ktime_to_timespec(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 void skb_timestamping_init(void);
  
  #ifdef CONFIG_NETWORK_PHY_TIMESTAMPING
  
  extern void skb_clone_tx_timestamp(struct sk_buff *skb);
  extern bool skb_defer_rx_timestamp(struct sk_buff *skb);
  
  #else /* CONFIG_NETWORK_PHY_TIMESTAMPING */
  
  static inline void skb_clone_tx_timestamp(struct sk_buff *skb)
  {
  }
  
  static inline bool skb_defer_rx_timestamp(struct sk_buff *skb)
  {
  	return false;
  }
  
  #endif /* !CONFIG_NETWORK_PHY_TIMESTAMPING */
  
  /**
   * skb_complete_tx_timestamp() - deliver cloned skb with tx timestamps
   *
   * @skb: clone of the the original outgoing packet
   * @hwtstamps: hardware time stamps
   *
   */
  void skb_complete_tx_timestamp(struct sk_buff *skb,
  			       struct skb_shared_hwtstamps *hwtstamps);

  /**
   * skb_tstamp_tx - queue clone of skb with send time stamps
   * @orig_skb:	the original outgoing packet
   * @hwtstamps:	hardware time stamps, may be NULL if not available
   *
   * If the skb has a socket associated, then this function clones the
   * skb (thus sharing the actual data and optional structures), stores
   * the optional hardware time stamping information (if non NULL) or
   * generates a software time stamp (otherwise), then queues the clone
   * to the error queue of the socket.  Errors are silently ignored.
   */
  extern void skb_tstamp_tx(struct sk_buff *orig_skb,
  			struct skb_shared_hwtstamps *hwtstamps);

  static inline void sw_tx_timestamp(struct sk_buff *skb)
  {

  	if (skb_shinfo(skb)->tx_flags & SKBTX_SW_TSTAMP &&
  	    !(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS))

  		skb_tstamp_tx(skb, NULL);
  }
  
  /**
   * skb_tx_timestamp() - Driver hook for transmit timestamping
   *
   * Ethernet MAC Drivers should call this function in their hard_xmit()
   * function as soon as possible after giving the sk_buff to the MAC
   * hardware, but before freeing the sk_buff.
   *
   * @skb: A socket buffer.
   */
  static inline void skb_tx_timestamp(struct sk_buff *skb)
  {

  	skb_clone_tx_timestamp(skb);

  	sw_tx_timestamp(skb);
  }

  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);
  }

  #endif
  #ifdef NET_SKBUFF_NF_DEFRAG_NEEDED

  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;

  #endif
  #ifdef NET_SKBUFF_NF_DEFRAG_NEEDED

  	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;

  #endif
  #ifdef NET_SKBUFF_NF_DEFRAG_NEEDED

  	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);

  #endif
  #ifdef NET_SKBUFF_NF_DEFRAG_NEEDED

  	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(const 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;

  }

  static inline void skb_record_rx_queue(struct sk_buff *skb, u16 rx_queue)
  {
  	skb->queue_mapping = rx_queue + 1;
  }

  static inline u16 skb_get_rx_queue(const struct sk_buff *skb)

  {
  	return skb->queue_mapping - 1;
  }

  static inline bool skb_rx_queue_recorded(const struct sk_buff *skb)

  {

  	return skb->queue_mapping != 0;

  }

  extern u16 __skb_tx_hash(const struct net_device *dev,
  			 const struct sk_buff *skb,
  			 unsigned int num_tx_queues);

  #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 (skb_is_nonlinear(skb) && 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;
  }

  /**
   * skb_checksum_none_assert - make sure skb ip_summed is CHECKSUM_NONE
   * @skb: skb to check
   *
   * fresh skbs have their ip_summed set to CHECKSUM_NONE.
   * Instead of forcing ip_summed to CHECKSUM_NONE, we can
   * use this helper, to document places where we make this assertion.
   */
  static inline void skb_checksum_none_assert(struct sk_buff *skb)
  {
  #ifdef DEBUG
  	BUG_ON(skb->ip_summed != CHECKSUM_NONE);
  #endif
  }

  bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off);

  #endif	/* __KERNEL__ */
  #endif	/* _LINUX_SKBUFF_H */