Import changeset

1 files changed, 963 insertions, 0 deletions

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
new file mode 100644
index 000000000000..17e48d0e937e
--- /dev/null
+++ b/include/linux/skbuff.h
@@ -0,0 +1,963 @@
+/*
+ *	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/sched.h>
+#include <linux/time.h>
+
+#include <asm/atomic.h>
+#include <asm/types.h>
+#include <linux/spinlock.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
+
+#ifdef __i386__
+#define NET_CALLER(arg) (*(((void**)&arg)-1))
+#else
+#define NET_CALLER(arg) __builtin_return_address(0)
+#endif
+
+#ifdef CONFIG_NETFILTER
+struct nf_conntrack {
+	atomic_t use;
+	void (*destroy)(struct nf_conntrack *);
+};
+
+struct nf_ct_info {
+	struct nf_conntrack *master;
+};
+#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 {
+	/* These two members must be first. */
+	struct sk_buff	* next;			/* Next buffer in list 				*/
+	struct sk_buff	* prev;			/* Previous buffer in list 			*/
+
+	struct sk_buff_head * list;		/* List we are on				*/
+	struct sock	*sk;			/* Socket we are owned by 			*/
+	struct timeval	stamp;			/* Time we arrived				*/
+	struct net_device	*dev;		/* Device we arrived on/are leaving by		*/
+
+	/* Transport layer header */
+	union
+	{
+		struct tcphdr	*th;
+		struct udphdr	*uh;
+		struct icmphdr	*icmph;
+		struct igmphdr	*igmph;
+		struct iphdr	*ipiph;
+		struct spxhdr	*spxh;
+		unsigned char	*raw;
+	} h;
+
+	/* Network layer header */
+	union
+	{
+		struct iphdr	*iph;
+		struct ipv6hdr	*ipv6h;
+		struct arphdr	*arph;
+		struct ipxhdr	*ipxh;
+		unsigned char	*raw;
+	} nh;
+  
+	/* Link layer header */
+	union 
+	{	
+	  	struct ethhdr	*ethernet;
+	  	unsigned char 	*raw;
+	} mac;
+
+	struct  dst_entry *dst;
+
+	/* 
+	 * This is the control buffer. It is free to use for every
+	 * layer. Please put your private variables there. If you
+	 * want to keep them across layers you have to do a skb_clone()
+	 * first. This is owned by whoever has the skb queued ATM.
+	 */ 
+	char		cb[48];	 
+
+	unsigned int 	len;			/* Length of actual data			*/
+	unsigned int	csum;			/* Checksum 					*/
+	volatile char 	used;			/* Data moved to user and not MSG_PEEK		*/
+	unsigned char	cloned, 		/* head may be cloned (check refcnt to be sure). */
+  			pkt_type,		/* Packet class					*/
+  			ip_summed;		/* Driver fed us an IP checksum			*/
+	__u32		priority;		/* Packet queueing priority			*/
+	atomic_t	users;			/* User count - see datagram.c,tcp.c 		*/
+	unsigned short	protocol;		/* Packet protocol from driver. 		*/
+	unsigned short	security;		/* Security level of packet			*/
+	unsigned int	truesize;		/* Buffer size 					*/
+
+	unsigned char	*head;			/* Head of buffer 				*/
+	unsigned char	*data;			/* Data head pointer				*/
+	unsigned char	*tail;			/* Tail pointer					*/
+	unsigned char 	*end;			/* End pointer					*/
+	void 		(*destructor)(struct sk_buff *);	/* Destruct function		*/
+#ifdef CONFIG_NETFILTER
+	/* Can be used for communication between hooks. */
+        unsigned long	nfmark;
+	/* Cache info */
+	__u32		nfcache;
+	/* Associated connection, if any */
+	struct nf_ct_info *nfct;
+#ifdef CONFIG_NETFILTER_DEBUG
+        unsigned int nf_debug;
+#endif
+#endif /*CONFIG_NETFILTER*/
+
+#if defined(CONFIG_HIPPI)
+	union{
+		__u32	ifield;
+	} private;
+#endif
+
+#ifdef CONFIG_NET_SCHED
+       __u32           tc_index;               /* traffic control index */
+#endif
+};
+
+#define SK_WMEM_MAX	65535
+#define SK_RMEM_MAX	65535
+
+#ifdef __KERNEL__
+/*
+ *	Handling routines are only of interest to the kernel
+ */
+#include <linux/malloc.h>
+
+#include <asm/system.h>
+
+extern void			__kfree_skb(struct sk_buff *skb);
+extern struct sk_buff *		skb_peek_copy(struct sk_buff_head *list);
+extern struct sk_buff *		alloc_skb(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 *		skb_copy_expand(const struct sk_buff *skb, 
+						int newheadroom,
+						int newtailroom,
+						int priority);
+#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);
+
+/* Backwards compatibility */
+#define skb_realloc_headroom(skb, nhr) skb_copy_expand(skb, nhr, skb_tailroom(skb), GFP_ATOMIC)
+
+/* Internal */
+static inline atomic_t *skb_datarefp(struct sk_buff *skb)
+{
+	return (atomic_t *)(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(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 (atomic_read(&skb->users) == 1 || atomic_dec_and_test(&skb->users))
+		__kfree_skb(skb);
+}
+
+/* Use this if you didn't touch the skb state [for fast switching] */
+static inline void kfree_skb_fast(struct sk_buff *skb)
+{
+	if (atomic_read(&skb->users) == 1 || atomic_dec_and_test(&skb->users))
+		kfree_skbmem(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(struct sk_buff *skb)
+{
+	return skb->cloned && atomic_read(skb_datarefp(skb)) != 1;
+}
+
+/**
+ *	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(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)
+{
+	if (skb_shared(skb)) {
+		struct sk_buff *nskb;
+		nskb = skb_clone(skb, pri);
+		kfree_skb(skb);
+		return 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)
+{
+	struct sk_buff *nskb;
+	if(!skb_cloned(skb))
+		return skb;
+	nskb=skb_copy(skb, pri);
+	kfree_skb(skb);		/* Free our shared copy */
+	return nskb;
+}
+
+/**
+ *	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(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 = (struct sk_buff *)list;
+	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.
+ */	
+ 
+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 = newsk;
+	prev->next = newsk;
+}
+
+
+/**
+ *	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 the list. This function takes the
+ *	list lock and can be used safely with other locking &sk_buff functions
+ *	safely.
+ *
+ *	A buffer cannot be placed on two lists at the same time.
+ */	
+
+static inline void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&list->lock, flags);
+	__skb_queue_head(list, newsk);
+	spin_unlock_irqrestore(&list->lock, flags);
+}
+
+/**
+ *	__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.
+ */	
+ 
+
+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 = newsk;
+	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 tail of the list. This function takes the
+ *	list lock and can be used safely with other locking &sk_buff functions
+ *	safely.
+ *
+ *	A buffer cannot be placed on two lists at the same time.
+ */	
+
+static inline void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&list->lock, flags);
+	__skb_queue_tail(list, newsk);
+	spin_unlock_irqrestore(&list->lock, flags);
+}
+
+/**
+ *	__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.
+ */
+
+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 = NULL;
+		result->prev = NULL;
+		result->list = NULL;
+	}
+	return result;
+}
+
+/**
+ *	skb_dequeue - remove from the head of the queue
+ *	@list: list to dequeue from
+ *
+ *	Remove the head of the list. The list lock is taken so the function
+ *	may be used safely with other locking list functions. The head item is
+ *	returned or %NULL if the list is empty.
+ */
+
+static inline struct sk_buff *skb_dequeue(struct sk_buff_head *list)
+{
+	long flags;
+	struct sk_buff *result;
+
+	spin_lock_irqsave(&list->lock, flags);
+	result = __skb_dequeue(list);
+	spin_unlock_irqrestore(&list->lock, flags);
+	return result;
+}
+
+/*
+ *	Insert a packet on a 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 = newsk;
+	prev->next = newsk;
+	newsk->list = list;
+	list->qlen++;
+}
+
+/**
+ *	skb_insert	-	insert a buffer
+ *	@old: buffer to insert before
+ *	@newsk: buffer to insert
+ *
+ *	Place a packet before a given packet in a list. The list locks are taken
+ *	and this function is atomic with respect to other list locked calls
+ *	A buffer cannot be placed on two lists at the same time.
+ */
+
+static inline void skb_insert(struct sk_buff *old, struct sk_buff *newsk)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&old->list->lock, flags);
+	__skb_insert(newsk, old->prev, old, old->list);
+	spin_unlock_irqrestore(&old->list->lock, flags);
+}
+
+/*
+ *	Place a packet after a given packet in a list.
+ */
+
+static inline void __skb_append(struct sk_buff *old, struct sk_buff *newsk)
+{
+	__skb_insert(newsk, old, old->next, old->list);
+}
+
+/**
+ *	skb_append	-	append a buffer
+ *	@old: buffer to insert after
+ *	@newsk: buffer to insert
+ *
+ *	Place a packet after a given packet in a list. The list locks are taken
+ *	and this function is atomic with respect to other list locked calls.
+ *	A buffer cannot be placed on two lists at the same time.
+ */
+
+
+static inline void skb_append(struct sk_buff *old, struct sk_buff *newsk)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&old->list->lock, flags);
+	__skb_append(old, newsk);
+	spin_unlock_irqrestore(&old->list->lock, flags);
+}
+
+/*
+ * remove sk_buff from list. _Must_ be called atomically, and with
+ * the list known..
+ */
+ 
+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 = NULL;
+	skb->prev = NULL;
+	skb->list = NULL;
+	next->prev = prev;
+	prev->next = next;
+}
+
+/**
+ *	skb_unlink	-	remove a buffer from a list
+ *	@skb: buffer to remove
+ *
+ *	Place a packet after a given packet in a list. The list locks are taken
+ *	and this function is atomic with respect to other list locked calls
+ *	
+ *	Works even without knowing the list it is sitting on, which can be 
+ *	handy at times. It also means that THE LIST MUST EXIST when you 
+ *	unlink. Thus a list must have its contents unlinked before it is
+ *	destroyed.
+ */
+
+static inline void skb_unlink(struct sk_buff *skb)
+{
+	struct sk_buff_head *list = skb->list;
+
+	if(list) {
+		unsigned long flags;
+
+		spin_lock_irqsave(&list->lock, flags);
+		if(skb->list == list)
+			__skb_unlink(skb, skb->list);
+		spin_unlock_irqrestore(&list->lock, flags);
+	}
+}
+
+/* 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.
+ */
+
+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;
+}
+
+/**
+ *	skb_dequeue - remove from the head of the queue
+ *	@list: list to dequeue from
+ *
+ *	Remove the head of the list. The list lock is taken so the function
+ *	may be used safely with other locking list functions. The tail item is
+ *	returned or %NULL if the list is empty.
+ */
+
+static inline struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list)
+{
+	long flags;
+	struct sk_buff *result;
+
+	spin_lock_irqsave(&list->lock, flags);
+	result = __skb_dequeue_tail(list);
+	spin_unlock_irqrestore(&list->lock, flags);
+	return result;
+}
+
+/*
+ *	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->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->tail+=len;
+	skb->len+=len;
+	if(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(skb->data<skb->head) {
+		skb_under_panic(skb, len, current_text_addr());
+	}
+	return skb->data;
+}
+
+static inline char *__skb_pull(struct sk_buff *skb, unsigned int len)
+{
+	skb->len-=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)
+{	
+	if (len > skb->len)
+		return NULL;
+	return __skb_pull(skb,len);
+}
+
+/**
+ *	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->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;
+}
+
+
+static inline void __skb_trim(struct sk_buff *skb, unsigned int len)
+{
+	skb->len = len;
+	skb->tail = skb->data+len;
+}
+
+/**
+ *	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);
+	}
+}
+
+/**
+ *	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_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 takes the list
+ *	lock and is atomic with respect to other list locking functions.
+ */
+
+
+static inline void skb_queue_purge(struct sk_buff_head *list)
+{
+	struct sk_buff *skb;
+	while ((skb=skb_dequeue(list))!=NULL)
+		kfree_skb(skb);
+}
+
+/**
+ *	__skb_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.
+ */
+
+
+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
+ *
+ *	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)
+{
+	struct sk_buff *skb;
+
+	skb = alloc_skb(length+16, GFP_ATOMIC);
+	if (skb)
+		skb_reserve(skb,16);
+	return skb;
+}
+
+/**
+ *	skb_cow - copy a buffer if need be
+ *	@skb: buffer to copy
+ *	@headroom: needed headroom
+ *
+ *	If the buffer passed lacks sufficient headroom or is a clone then
+ *	it is copied and the additional headroom made available. If there
+ *	is no free memory %NULL is returned. The new buffer is returned if
+ *	a copy was made (and the old one dropped a reference). The existing
+ *	buffer is returned otherwise.
+ *
+ *	This function primarily exists to avoid making two copies when making
+ *	a writable copy of a buffer and then growing the headroom.
+ */
+ 
+
+static inline struct sk_buff *
+skb_cow(struct sk_buff *skb, unsigned int headroom)
+{
+	headroom = (headroom+15)&~15;
+
+	if ((unsigned)skb_headroom(skb) < headroom || skb_cloned(skb)) {
+		struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
+		kfree_skb(skb);
+		skb = skb2;
+	}
+	return skb;
+}
+
+#define skb_queue_walk(queue, skb) \
+		for (skb = (queue)->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(struct sk_buff *from, int offset, char *to,int size);
+extern int			skb_copy_datagram_iovec(struct sk_buff *from, int offset, struct iovec *to,int size);
+extern void			skb_free_datagram(struct sock * sk, struct sk_buff *skb);
+
+extern void skb_init(void);
+extern void skb_add_mtu(int mtu);
+
+#ifdef CONFIG_NETFILTER
+static inline void
+nf_conntrack_put(struct nf_ct_info *nfct)
+{
+	if (nfct && atomic_dec_and_test(&nfct->master->use))
+		nfct->master->destroy(nfct->master);
+}
+static inline void
+nf_conntrack_get(struct nf_ct_info *nfct)
+{
+	if (nfct)
+		atomic_inc(&nfct->master->use);
+}
+#endif
+
+#endif	/* __KERNEL__ */
+#endif	/* _LINUX_SKBUFF_H */