Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 1253 insertions, 0 deletions

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
new file mode 100644
index 000000000000..aa35797ebfbf
--- /dev/null
+++ b/include/linux/skbuff.h
@@ -0,0 +1,1253 @@
+/*
+ *	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/config.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/mm.h>
+#include <linux/highmem.h>
+#include <linux/poll.h>
+#include <linux/net.h>
+#include <net/checksum.h>
+
+#define HAVE_ALLOC_SKB		/* For the drivers to know */
+#define HAVE_ALIGNABLE_SKB	/* Ditto 8)		   */
+#define SLAB_SKB 		/* Slabified skbuffs 	   */
+
+#define CHECKSUM_NONE 0
+#define CHECKSUM_HW 1
+#define CHECKSUM_UNNECESSARY 2
+
+#define SKB_DATA_ALIGN(X)	(((X) + (SMP_CACHE_BYTES - 1)) & \
+				 ~(SMP_CACHE_BYTES - 1))
+#define SKB_MAX_ORDER(X, ORDER)	(((PAGE_SIZE << (ORDER)) - (X) - \
+				  sizeof(struct skb_shared_info)) & \
+				  ~(SMP_CACHE_BYTES - 1))
+#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)
+ *
+ *	HW: 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 HW,
+ *	    not UNNECESSARY.
+ *
+ * B. Checksumming on output.
+ *
+ *	NONE: skb is checksummed by protocol or csum is not required.
+ *
+ *	HW: device is required to csum packet as seen by hard_start_xmit
+ *	from skb->h.raw to the end and to record the checksum
+ *	at skb->h.raw+skb->csum.
+ *
+ *	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)
+ *
+ *	Any questions? No questions, good. 		--ANK
+ */
+
+#ifdef __i386__
+#define NET_CALLER(arg) (*(((void **)&arg) - 1))
+#else
+#define NET_CALLER(arg) __builtin_return_address(0)
+#endif
+
+struct net_device;
+
+#ifdef CONFIG_NETFILTER
+struct nf_conntrack {
+	atomic_t use;
+	void (*destroy)(struct nf_conntrack *);
+};
+
+#ifdef CONFIG_BRIDGE_NETFILTER
+struct nf_bridge_info {
+	atomic_t use;
+	struct net_device *physindev;
+	struct net_device *physoutdev;
+#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
+	struct net_device *netoutdev;
+#endif
+	unsigned int mask;
+	unsigned long data[32 / sizeof(unsigned long)];
+};
+#endif
+
+#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;
+	__u16 page_offset;
+	__u16 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 int	nr_frags;
+	unsigned short	tso_size;
+	unsigned short	tso_segs;
+	struct sk_buff	*frag_list;
+	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.  It is up to the users of the skb to agree on
+ * where the payload starts.
+ *
+ * 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)
+
+/** 
+ *	struct sk_buff - socket buffer
+ *	@next: Next buffer in list
+ *	@prev: Previous buffer in list
+ *	@list: List we are on
+ *	@sk: Socket we are owned by
+ *	@stamp: Time we arrived
+ *	@dev: Device we arrived on/are leaving by
+ *	@input_dev: Device we arrived on
+ *      @real_dev: The real device we are using
+ *	@h: Transport layer header
+ *	@nh: Network layer header
+ *	@mac: Link layer header
+ *	@dst: FIXME: Describe this field
+ *	@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
+ *	@csum: Checksum
+ *	@__unused: Dead field, may be reused
+ *	@cloned: Head may be cloned (check refcnt to be sure)
+ *	@nohdr: Payload reference only, must not modify header
+ *	@pkt_type: Packet class
+ *	@ip_summed: Driver fed us an IP checksum
+ *	@priority: Packet queueing priority
+ *	@users: User count - see {datagram,tcp}.c
+ *	@protocol: Packet protocol from driver
+ *	@security: Security level of packet
+ *	@truesize: Buffer size 
+ *	@head: Head of buffer
+ *	@data: Data head pointer
+ *	@tail: Tail pointer
+ *	@end: End pointer
+ *	@destructor: Destruct function
+ *	@nfmark: Can be used for communication between hooks
+ *	@nfcache: Cache info
+ *	@nfct: Associated connection, if any
+ *	@nfctinfo: Relationship of this skb to the connection
+ *	@nf_debug: Netfilter debugging
+ *	@nf_bridge: Saved data about a bridged frame - see br_netfilter.c
+ *      @private: Data which is private to the HIPPI implementation
+ *	@tc_index: Traffic control index
+ *	@tc_verd: traffic control verdict
+ *	@tc_classid: traffic control classid
+ */
+
+struct sk_buff {
+	/* These two members must be first. */
+	struct sk_buff		*next;
+	struct sk_buff		*prev;
+
+	struct sk_buff_head	*list;
+	struct sock		*sk;
+	struct timeval		stamp;
+	struct net_device	*dev;
+	struct net_device	*input_dev;
+	struct net_device	*real_dev;
+
+	union {
+		struct tcphdr	*th;
+		struct udphdr	*uh;
+		struct icmphdr	*icmph;
+		struct igmphdr	*igmph;
+		struct iphdr	*ipiph;
+		struct ipv6hdr	*ipv6h;
+		unsigned char	*raw;
+	} h;
+
+	union {
+		struct iphdr	*iph;
+		struct ipv6hdr	*ipv6h;
+		struct arphdr	*arph;
+		unsigned char	*raw;
+	} nh;
+
+	union {
+	  	unsigned char 	*raw;
+	} mac;
+
+	struct  dst_entry	*dst;
+	struct	sec_path	*sp;
+
+	/*
+	 * 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[40];
+
+	unsigned int		len,
+				data_len,
+				mac_len,
+				csum;
+	unsigned char		local_df,
+				cloned:1,
+				nohdr:1,
+				pkt_type,
+				ip_summed;
+	__u32			priority;
+	unsigned short		protocol,
+				security;
+
+	void			(*destructor)(struct sk_buff *skb);
+#ifdef CONFIG_NETFILTER
+        unsigned long		nfmark;
+	__u32			nfcache;
+	__u32			nfctinfo;
+	struct nf_conntrack	*nfct;
+#ifdef CONFIG_NETFILTER_DEBUG
+        unsigned int		nf_debug;
+#endif
+#ifdef CONFIG_BRIDGE_NETFILTER
+	struct nf_bridge_info	*nf_bridge;
+#endif
+#endif /* CONFIG_NETFILTER */
+#if defined(CONFIG_HIPPI)
+	union {
+		__u32		ifield;
+	} private;
+#endif
+#ifdef CONFIG_NET_SCHED
+       __u32			tc_index;        /* traffic control index */
+#ifdef CONFIG_NET_CLS_ACT
+	__u32           tc_verd;               /* traffic control verdict */
+	__u32           tc_classid;            /* traffic control classid */
+#endif
+
+#endif
+
+
+	/* These elements must be at the end, see alloc_skb() for details.  */
+	unsigned int		truesize;
+	atomic_t		users;
+	unsigned char		*head,
+				*data,
+				*tail,
+				*end;
+};
+
+#ifdef __KERNEL__
+/*
+ *	Handling routines are only of interest to the kernel
+ */
+#include <linux/slab.h>
+
+#include <asm/system.h>
+
+extern void	       __kfree_skb(struct sk_buff *skb);
+extern struct sk_buff *alloc_skb(unsigned int size, int priority);
+extern struct sk_buff *alloc_skb_from_cache(kmem_cache_t *cp,
+					    unsigned int size, int priority);
+extern void	       kfree_skbmem(struct sk_buff *skb);
+extern struct sk_buff *skb_clone(struct sk_buff *skb, int priority);
+extern struct sk_buff *skb_copy(const struct sk_buff *skb, int priority);
+extern struct sk_buff *pskb_copy(struct sk_buff *skb, int gfp_mask);
+extern int	       pskb_expand_head(struct sk_buff *skb,
+					int nhead, int ntail, int 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,
+				       int priority);
+extern struct sk_buff *		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);
+
+/* Internal */
+#define skb_shinfo(SKB)		((struct skb_shared_info *)((SKB)->end))
+
+/**
+ *	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_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.
+ */
+
+/**
+ *	kfree_skb - free an sk_buff
+ *	@skb: buffer to free
+ *
+ *	Drop a reference to the buffer and free it if the usage count has
+ *	hit zero.
+ */
+static inline void kfree_skb(struct sk_buff *skb)
+{
+	if (likely(atomic_read(&skb->users) == 1))
+		smp_rmb();
+	else if (likely(!atomic_dec_and_test(&skb->users)))
+		return;
+	__kfree_skb(skb);
+}
+
+/**
+ *	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, int 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, int 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;
+}
+
+static inline void skb_queue_head_init(struct sk_buff_head *list)
+{
+	spin_lock_init(&list->lock);
+	list->prev = list->next = (struct sk_buff *)list;
+	list->qlen = 0;
+}
+
+/*
+ *	Insert an sk_buff at the start of a list.
+ *
+ *	The "__skb_xxxx()" functions are the non-atomic ones that
+ *	can only be called with interrupts disabled.
+ */
+
+/**
+ *	__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)
+{
+	struct sk_buff *prev, *next;
+
+	newsk->list = list;
+	list->qlen++;
+	prev = (struct sk_buff *)list;
+	next = prev->next;
+	newsk->next = next;
+	newsk->prev = prev;
+	next->prev  = prev->next = 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)
+{
+	struct sk_buff *prev, *next;
+
+	newsk->list = list;
+	list->qlen++;
+	next = (struct sk_buff *)list;
+	prev = next->prev;
+	newsk->next = next;
+	newsk->prev = prev;
+	next->prev  = prev->next = newsk;
+}
+
+
+/**
+ *	__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 *next, *prev, *result;
+
+	prev = (struct sk_buff *) list;
+	next = prev->next;
+	result = NULL;
+	if (next != prev) {
+		result	     = next;
+		next	     = next->next;
+		list->qlen--;
+		next->prev   = prev;
+		prev->next   = next;
+		result->next = result->prev = NULL;
+		result->list = NULL;
+	}
+	return result;
+}
+
+
+/*
+ *	Insert a packet on a list.
+ */
+extern void        skb_insert(struct sk_buff *old, struct sk_buff *newsk);
+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;
+	newsk->list = list;
+	list->qlen++;
+}
+
+/*
+ *	Place a packet after a given packet in a list.
+ */
+extern void	   skb_append(struct sk_buff *old, struct sk_buff *newsk);
+static inline void __skb_append(struct sk_buff *old, struct sk_buff *newsk)
+{
+	__skb_insert(newsk, old, old->next, old->list);
+}
+
+/*
+ * remove sk_buff from list. _Must_ be called atomically, and with
+ * the list known..
+ */
+extern void	   skb_unlink(struct sk_buff *skb);
+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;
+	skb->list  = NULL;
+	next->prev = prev;
+	prev->next = next;
+}
+
+
+/* XXX: more streamlined implementation */
+
+/**
+ *	__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;
+}
+
+#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))
+
+/*
+ *	Add data to an sk_buff
+ */
+static inline unsigned char *__skb_put(struct sk_buff *skb, unsigned int len)
+{
+	unsigned char *tmp = skb->tail;
+	SKB_LINEAR_ASSERT(skb);
+	skb->tail += len;
+	skb->len  += len;
+	return tmp;
+}
+
+/**
+ *	skb_put - add data to a buffer
+ *	@skb: buffer to use
+ *	@len: amount of data to add
+ *
+ *	This function extends the used data area of the buffer. If this would
+ *	exceed the total buffer size the kernel will panic. A pointer to the
+ *	first byte of the extra data is returned.
+ */
+static inline unsigned char *skb_put(struct sk_buff *skb, unsigned int len)
+{
+	unsigned char *tmp = skb->tail;
+	SKB_LINEAR_ASSERT(skb);
+	skb->tail += len;
+	skb->len  += len;
+	if (unlikely(skb->tail>skb->end))
+		skb_over_panic(skb, len, current_text_addr());
+	return tmp;
+}
+
+static inline unsigned char *__skb_push(struct sk_buff *skb, unsigned int len)
+{
+	skb->data -= len;
+	skb->len  += len;
+	return skb->data;
+}
+
+/**
+ *	skb_push - add data to the start of a buffer
+ *	@skb: buffer to use
+ *	@len: amount of data to add
+ *
+ *	This function extends the used data area of the buffer at the buffer
+ *	start. If this would exceed the total buffer headroom the kernel will
+ *	panic. A pointer to the first byte of the extra data is returned.
+ */
+static inline unsigned char *skb_push(struct sk_buff *skb, unsigned int len)
+{
+	skb->data -= len;
+	skb->len  += len;
+	if (unlikely(skb->data<skb->head))
+		skb_under_panic(skb, len, current_text_addr());
+	return skb->data;
+}
+
+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;
+}
+
+/**
+ *	skb_pull - remove data from the start of a buffer
+ *	@skb: buffer to use
+ *	@len: amount of data to remove
+ *
+ *	This function removes data from the start of a buffer, returning
+ *	the memory to the headroom. A pointer to the next data in the buffer
+ *	is returned. Once the data has been pulled future pushes will overwrite
+ *	the old data.
+ */
+static inline unsigned char *skb_pull(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 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, unsigned int len)
+{
+	skb->data += len;
+	skb->tail += 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(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
+
+extern int ___pskb_trim(struct sk_buff *skb, unsigned int len, int realloc);
+
+static inline void __skb_trim(struct sk_buff *skb, unsigned int len)
+{
+	if (!skb->data_len) {
+		skb->len  = len;
+		skb->tail = skb->data + len;
+	} else
+		___pskb_trim(skb, len, 0);
+}
+
+/**
+ *	skb_trim - remove end from a buffer
+ *	@skb: buffer to alter
+ *	@len: new length
+ *
+ *	Cut the length of a buffer down by removing data from the tail. If
+ *	the buffer is already under the length specified it is not modified.
+ */
+static inline void skb_trim(struct sk_buff *skb, unsigned int len)
+{
+	if (skb->len > len)
+		__skb_trim(skb, len);
+}
+
+
+static inline int __pskb_trim(struct sk_buff *skb, unsigned int len)
+{
+	if (!skb->data_len) {
+		skb->len  = len;
+		skb->tail = skb->data+len;
+		return 0;
+	}
+	return ___pskb_trim(skb, len, 1);
+}
+
+static inline int pskb_trim(struct sk_buff *skb, unsigned int len)
+{
+	return (len < skb->len) ? __pskb_trim(skb, len) : 0;
+}
+
+/**
+ *	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 sending
+ *	@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 in there is no free memory.
+ */
+#ifndef CONFIG_HAVE_ARCH_DEV_ALLOC_SKB
+static inline struct sk_buff *__dev_alloc_skb(unsigned int length,
+					      int gfp_mask)
+{
+	struct sk_buff *skb = alloc_skb(length + 16, gfp_mask);
+	if (likely(skb))
+		skb_reserve(skb, 16);
+	return skb;
+}
+#else
+extern struct sk_buff *__dev_alloc_skb(unsigned int length, int gfp_mask);
+#endif
+
+/**
+ *	dev_alloc_skb - allocate an skbuff for sending
+ *	@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 in there is no free memory. Although this function
+ *	allocates memory it can be called from an interrupt.
+ */
+static inline struct sk_buff *dev_alloc_skb(unsigned int length)
+{
+	return __dev_alloc_skb(length, GFP_ATOMIC);
+}
+
+/**
+ *	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)
+{
+	int delta = (headroom > 16 ? headroom : 16) - skb_headroom(skb);
+
+	if (delta < 0)
+		delta = 0;
+
+	if (delta || skb_cloned(skb))
+		return pskb_expand_head(skb, (delta + 15) & ~15, 0, GFP_ATOMIC);
+	return 0;
+}
+
+/**
+ *	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. Returns the buffer, which may be a replacement
+ *	for the original, or NULL for out of memory - in which case
+ *	the original buffer is still freed.
+ */
+ 
+static inline struct sk_buff *skb_padto(struct sk_buff *skb, unsigned int len)
+{
+	unsigned int size = skb->len;
+	if (likely(size >= len))
+		return skb;
+	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;
+		unsigned int 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;
+}
+
+/**
+ *	skb_linearize - convert paged skb to linear one
+ *	@skb: buffer to linarize
+ *	@gfp: allocation mode
+ *
+ *	If there is no free memory -ENOMEM is returned, otherwise zero
+ *	is returned and the old skb data released.
+ */
+extern int __skb_linearize(struct sk_buff *skb, int gfp);
+static inline int skb_linearize(struct sk_buff *skb, int gfp)
+{
+	return __skb_linearize(skb, gfp);
+}
+
+/**
+ *	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_HW 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, int len)
+{
+	if (skb->ip_summed == CHECKSUM_HW)
+		skb->csum = csum_sub(skb->csum, csum_partial(start, len, 0));
+}
+
+/**
+ *	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 (len >= skb->len)
+		return 0;
+	if (skb->ip_summed == CHECKSUM_HW)
+		skb->ip_summed = CHECKSUM_NONE;
+	return __pskb_trim(skb, len);
+}
+
+static inline void *kmap_skb_frag(const skb_frag_t *frag)
+{
+#ifdef CONFIG_HIGHMEM
+	BUG_ON(in_irq());
+
+	local_bh_disable();
+#endif
+	return kmap_atomic(frag->page, KM_SKB_DATA_SOFTIRQ);
+}
+
+static inline void kunmap_skb_frag(void *vaddr)
+{
+	kunmap_atomic(vaddr, KM_SKB_DATA_SOFTIRQ);
+#ifdef CONFIG_HIGHMEM
+	local_bh_enable();
+#endif
+}
+
+#define skb_queue_walk(queue, skb) \
+		for (skb = (queue)->next;					\
+		     prefetch(skb->next), (skb != (struct sk_buff *)(queue));	\
+		     skb = skb->next)
+
+
+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(const
+							struct sk_buff *skb,
+							int hlen,
+							struct iovec *iov);
+extern void	       skb_free_datagram(struct sock *sk, struct sk_buff *skb);
+extern unsigned int    skb_checksum(const struct sk_buff *skb, int offset,
+				    int len, unsigned int csum);
+extern int	       skb_copy_bits(const struct sk_buff *skb, int offset,
+				     void *to, int len);
+extern unsigned int    skb_copy_and_csum_bits(const struct sk_buff *skb,
+					      int offset, u8 *to, int len,
+					      unsigned int csum);
+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);
+
+static inline void *skb_header_pointer(const struct sk_buff *skb, int offset,
+				       int len, void *buffer)
+{
+	int hlen = skb_headlen(skb);
+
+	if (offset + len <= hlen)
+		return skb->data + offset;
+
+	if (skb_copy_bits(skb, offset, buffer, len) < 0)
+		return NULL;
+
+	return buffer;
+}
+
+extern void skb_init(void);
+extern void skb_add_mtu(int mtu);
+
+#ifdef CONFIG_NETFILTER
+static inline void nf_conntrack_put(struct nf_conntrack *nfct)
+{
+	if (nfct && atomic_dec_and_test(&nfct->use))
+		nfct->destroy(nfct);
+}
+static inline void nf_conntrack_get(struct nf_conntrack *nfct)
+{
+	if (nfct)
+		atomic_inc(&nfct->use);
+}
+static inline void nf_reset(struct sk_buff *skb)
+{
+	nf_conntrack_put(skb->nfct);
+	skb->nfct = NULL;
+#ifdef CONFIG_NETFILTER_DEBUG
+	skb->nf_debug = 0;
+#endif
+}
+static inline void nf_reset_debug(struct sk_buff *skb)
+{
+#ifdef CONFIG_NETFILTER_DEBUG
+	skb->nf_debug = 0;
+#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 */
+#else /* CONFIG_NETFILTER */
+static inline void nf_reset(struct sk_buff *skb) {}
+#endif /* CONFIG_NETFILTER */
+
+#endif	/* __KERNEL__ */
+#endif	/* _LINUX_SKBUFF_H */