[deliverable/linux.git] / net / core / skbuff.c

/*
 *	Routines having to do with the 'struct sk_buff' memory handlers.
 *
 *	Authors:	Alan Cox <alan@lxorguk.ukuu.org.uk>
 *			Florian La Roche <rzsfl@rz.uni-sb.de>
 *
 *	Fixes:
 *		Alan Cox	:	Fixed the worst of the load
 *					balancer bugs.
 *		Dave Platt	:	Interrupt stacking fix.
 *	Richard Kooijman	:	Timestamp fixes.
 *		Alan Cox	:	Changed buffer format.
 *		Alan Cox	:	destructor hook for AF_UNIX etc.
 *		Linus Torvalds	:	Better skb_clone.
 *		Alan Cox	:	Added skb_copy.
 *		Alan Cox	:	Added all the changed routines Linus
 *					only put in the headers
 *		Ray VanTassle	:	Fixed --skb->lock in free
 *		Alan Cox	:	skb_copy copy arp field
 *		Andi Kleen	:	slabified it.
 *		Robert Olsson	:	Removed skb_head_pool
 *
 *	NOTE:
 *		The __skb_ routines should be called with interrupts
 *	disabled, or you better be *real* sure that the operation is atomic
 *	with respect to whatever list is being frobbed (e.g. via lock_sock()
 *	or via disabling bottom half handlers, etc).
 *
 *	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.
 */

/*
 *	The functions in this file will not compile correctly with gcc 2.4.x
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/in.h>
#include <linux/inet.h>
#include <linux/slab.h>
#include <linux/netdevice.h>
#ifdef CONFIG_NET_CLS_ACT
#include <net/pkt_sched.h>
#endif
#include <linux/string.h>
#include <linux/skbuff.h>
#include <linux/splice.h>
#include <linux/cache.h>
#include <linux/rtnetlink.h>
#include <linux/init.h>
#include <linux/scatterlist.h>

#include <net/protocol.h>
#include <net/dst.h>
#include <net/sock.h>
#include <net/checksum.h>
#include <net/xfrm.h>

#include <asm/uaccess.h>
#include <asm/system.h>

#include "kmap_skb.h"

static struct kmem_cache *skbuff_head_cache __read_mostly;
static struct kmem_cache *skbuff_fclone_cache __read_mostly;

static void sock_pipe_buf_release(struct pipe_inode_info *pipe,
				  struct pipe_buffer *buf)
{
	put_page(buf->page);
}

static void sock_pipe_buf_get(struct pipe_inode_info *pipe,
				struct pipe_buffer *buf)
{
	get_page(buf->page);
}

static int sock_pipe_buf_steal(struct pipe_inode_info *pipe,
			       struct pipe_buffer *buf)
{
	return 1;
}


/* Pipe buffer operations for a socket. */
static struct pipe_buf_operations sock_pipe_buf_ops = {
	.can_merge = 0,
	.map = generic_pipe_buf_map,
	.unmap = generic_pipe_buf_unmap,
	.confirm = generic_pipe_buf_confirm,
	.release = sock_pipe_buf_release,
	.steal = sock_pipe_buf_steal,
	.get = sock_pipe_buf_get,
};

/*
 *	Keep out-of-line to prevent kernel bloat.
 *	__builtin_return_address is not used because it is not always
 *	reliable.
 */

/**
 *	skb_over_panic	- 	private function
 *	@skb: buffer
 *	@sz: size
 *	@here: address
 *
 *	Out of line support code for skb_put(). Not user callable.
 */
void skb_over_panic(struct sk_buff *skb, int sz, void *here)
{
	printk(KERN_EMERG "skb_over_panic: text:%p len:%d put:%d head:%p "
			  "data:%p tail:%#lx end:%#lx dev:%s\n",
	       here, skb->len, sz, skb->head, skb->data,
	       (unsigned long)skb->tail, (unsigned long)skb->end,
	       skb->dev ? skb->dev->name : "<NULL>");
	BUG();
}

/**
 *	skb_under_panic	- 	private function
 *	@skb: buffer
 *	@sz: size
 *	@here: address
 *
 *	Out of line support code for skb_push(). Not user callable.
 */

void skb_under_panic(struct sk_buff *skb, int sz, void *here)
{
	printk(KERN_EMERG "skb_under_panic: text:%p len:%d put:%d head:%p "
			  "data:%p tail:%#lx end:%#lx dev:%s\n",
	       here, skb->len, sz, skb->head, skb->data,
	       (unsigned long)skb->tail, (unsigned long)skb->end,
	       skb->dev ? skb->dev->name : "<NULL>");
	BUG();
}

/* 	Allocate a new skbuff. We do this ourselves so we can fill in a few
 *	'private' fields and also do memory statistics to find all the
 *	[BEEP] leaks.
 *
 */

/**
 *	__alloc_skb	-	allocate a network buffer
 *	@size: size to allocate
 *	@gfp_mask: allocation mask
 *	@fclone: allocate from fclone cache instead of head cache
 *		and allocate a cloned (child) skb
 *	@node: numa node to allocate memory on
 *
 *	Allocate a new &sk_buff. The returned buffer has no headroom and a
 *	tail room of size bytes. The object has a reference count of one.
 *	The return is the buffer. On a failure the return is %NULL.
 *
 *	Buffers may only be allocated from interrupts using a @gfp_mask of
 *	%GFP_ATOMIC.
 */
struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
			    int fclone, int node)
{
	struct kmem_cache *cache;
	struct skb_shared_info *shinfo;
	struct sk_buff *skb;
	u8 *data;

	cache = fclone ? skbuff_fclone_cache : skbuff_head_cache;

	/* Get the HEAD */
	skb = kmem_cache_alloc_node(cache, gfp_mask & ~__GFP_DMA, node);
	if (!skb)
		goto out;

	size = SKB_DATA_ALIGN(size);
	data = kmalloc_node_track_caller(size + sizeof(struct skb_shared_info),
			gfp_mask, node);
	if (!data)
		goto nodata;

	/*
	 * Only clear those fields we need to clear, not those that we will
	 * actually initialise below. Hence, don't put any more fields after
	 * the tail pointer in struct sk_buff!
	 */
	memset(skb, 0, offsetof(struct sk_buff, tail));
	skb->truesize = size + sizeof(struct sk_buff);
	atomic_set(&skb->users, 1);
	skb->head = data;
	skb->data = data;
	skb_reset_tail_pointer(skb);
	skb->end = skb->tail + size;
	/* make sure we initialize shinfo sequentially */
	shinfo = skb_shinfo(skb);
	atomic_set(&shinfo->dataref, 1);
	shinfo->nr_frags  = 0;
	shinfo->gso_size = 0;
	shinfo->gso_segs = 0;
	shinfo->gso_type = 0;
	shinfo->ip6_frag_id = 0;
	shinfo->frag_list = NULL;

	if (fclone) {
		struct sk_buff *child = skb + 1;
		atomic_t *fclone_ref = (atomic_t *) (child + 1);

		skb->fclone = SKB_FCLONE_ORIG;
		atomic_set(fclone_ref, 1);

		child->fclone = SKB_FCLONE_UNAVAILABLE;
	}
out:
	return skb;
nodata:
	kmem_cache_free(cache, skb);
	skb = NULL;
	goto out;
}

/**
 *	__netdev_alloc_skb - allocate an skbuff for rx on a specific device
 *	@dev: network device to receive on
 *	@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.
 */
struct sk_buff *__netdev_alloc_skb(struct net_device *dev,
		unsigned int length, gfp_t gfp_mask)
{
	int node = dev->dev.parent ? dev_to_node(dev->dev.parent) : -1;
	struct sk_buff *skb;

	skb = __alloc_skb(length + NET_SKB_PAD, gfp_mask, 0, node);
	if (likely(skb)) {
		skb_reserve(skb, NET_SKB_PAD);
		skb->dev = dev;
	}
	return skb;
}

struct page *__netdev_alloc_page(struct net_device *dev, gfp_t gfp_mask)
{
	int node = dev->dev.parent ? dev_to_node(dev->dev.parent) : -1;
	struct page *page;

	page = alloc_pages_node(node, gfp_mask, 0);
	return page;
}
EXPORT_SYMBOL(__netdev_alloc_page);

void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page, int off,
		int size)
{
	skb_fill_page_desc(skb, i, page, off, size);
	skb->len += size;
	skb->data_len += size;
	skb->truesize += size;
}
EXPORT_SYMBOL(skb_add_rx_frag);

/**
 *	dev_alloc_skb - allocate an skbuff for receiving
 *	@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.
 */
struct sk_buff *dev_alloc_skb(unsigned int length)
{
	/*
	 * There is more code here than it seems:
	 * __dev_alloc_skb is an inline
	 */
	return __dev_alloc_skb(length, GFP_ATOMIC);
}
EXPORT_SYMBOL(dev_alloc_skb);

static void skb_drop_list(struct sk_buff **listp)
{
	struct sk_buff *list = *listp;

	*listp = NULL;

	do {
		struct sk_buff *this = list;
		list = list->next;
		kfree_skb(this);
	} while (list);
}

static inline void skb_drop_fraglist(struct sk_buff *skb)
{
	skb_drop_list(&skb_shinfo(skb)->frag_list);
}

static void skb_clone_fraglist(struct sk_buff *skb)
{
	struct sk_buff *list;

	for (list = skb_shinfo(skb)->frag_list; list; list = list->next)
		skb_get(list);
}

static void skb_release_data(struct sk_buff *skb)
{
	if (!skb->cloned ||
	    !atomic_sub_return(skb->nohdr ? (1 << SKB_DATAREF_SHIFT) + 1 : 1,
			       &skb_shinfo(skb)->dataref)) {
		if (skb_shinfo(skb)->nr_frags) {
			int i;
			for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
				put_page(skb_shinfo(skb)->frags[i].page);
		}

		if (skb_shinfo(skb)->frag_list)
			skb_drop_fraglist(skb);

		kfree(skb->head);
	}
}

/*
 *	Free an skbuff by memory without cleaning the state.
 */
static void kfree_skbmem(struct sk_buff *skb)
{
	struct sk_buff *other;
	atomic_t *fclone_ref;

	switch (skb->fclone) {
	case SKB_FCLONE_UNAVAILABLE:
		kmem_cache_free(skbuff_head_cache, skb);
		break;

	case SKB_FCLONE_ORIG:
		fclone_ref = (atomic_t *) (skb + 2);
		if (atomic_dec_and_test(fclone_ref))
			kmem_cache_free(skbuff_fclone_cache, skb);
		break;

	case SKB_FCLONE_CLONE:
		fclone_ref = (atomic_t *) (skb + 1);
		other = skb - 1;

		/* The clone portion is available for
		 * fast-cloning again.
		 */
		skb->fclone = SKB_FCLONE_UNAVAILABLE;

		if (atomic_dec_and_test(fclone_ref))
			kmem_cache_free(skbuff_fclone_cache, other);
		break;
	}
}

static void skb_release_head_state(struct sk_buff *skb)
{
	dst_release(skb->dst);
#ifdef CONFIG_XFRM
	secpath_put(skb->sp);
#endif
	if (skb->destructor) {
		WARN_ON(in_irq());
		skb->destructor(skb);
	}
#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
	nf_conntrack_put(skb->nfct);
	nf_conntrack_put_reasm(skb->nfct_reasm);
#endif
#ifdef CONFIG_BRIDGE_NETFILTER
	nf_bridge_put(skb->nf_bridge);
#endif
/* XXX: IS this still necessary? - JHS */
#ifdef CONFIG_NET_SCHED
	skb->tc_index = 0;
#ifdef CONFIG_NET_CLS_ACT
	skb->tc_verd = 0;
#endif
#endif
}

/* Free everything but the sk_buff shell. */
static void skb_release_all(struct sk_buff *skb)
{
	skb_release_head_state(skb);
	skb_release_data(skb);
}

/**
 *	__kfree_skb - private function
 *	@skb: buffer
 *
 *	Free an sk_buff. Release anything attached to the buffer.
 *	Clean the state. This is an internal helper function. Users should
 *	always call kfree_skb
 */

void __kfree_skb(struct sk_buff *skb)
{
	skb_release_all(skb);
	kfree_skbmem(skb);
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Routines having to do with the 'struct sk_buff' memory handlers.
	3	*
113aa838	4	* Authors: Alan Cox <alan@lxorguk.ukuu.org.uk>
1da177e4 LT	5	* Florian La Roche <rzsfl@rz.uni-sb.de>
1da177e4 LT	6	*
1da177e4 LT	7	* Fixes:
	8	* Alan Cox : Fixed the worst of the load
	9	* balancer bugs.
	10	* Dave Platt : Interrupt stacking fix.
	11	* Richard Kooijman : Timestamp fixes.
	12	* Alan Cox : Changed buffer format.
	13	* Alan Cox : destructor hook for AF_UNIX etc.
	14	* Linus Torvalds : Better skb_clone.
	15	* Alan Cox : Added skb_copy.
	16	* Alan Cox : Added all the changed routines Linus
	17	* only put in the headers
	18	* Ray VanTassle : Fixed --skb->lock in free
	19	* Alan Cox : skb_copy copy arp field
	20	* Andi Kleen : slabified it.
	21	* Robert Olsson : Removed skb_head_pool
	22	*
	23	* NOTE:
	24	* The __skb_ routines should be called with interrupts
	25	* disabled, or you better be real sure that the operation is atomic
	26	* with respect to whatever list is being frobbed (e.g. via lock_sock()
	27	* or via disabling bottom half handlers, etc).
	28	*
	29	* This program is free software; you can redistribute it and/or
	30	* modify it under the terms of the GNU General Public License
	31	* as published by the Free Software Foundation; either version
	32	* 2 of the License, or (at your option) any later version.
	33	*/
	34
	35	/*
	36	* The functions in this file will not compile correctly with gcc 2.4.x
	37	*/
	38
1da177e4 LT	39	#include <linux/module.h>
	40	#include <linux/types.h>
	41	#include <linux/kernel.h>
1da177e4 LT	42	#include <linux/mm.h>
	43	#include <linux/interrupt.h>
	44	#include <linux/in.h>
	45	#include <linux/inet.h>
	46	#include <linux/slab.h>
	47	#include <linux/netdevice.h>
	48	#ifdef CONFIG_NET_CLS_ACT
	49	#include <net/pkt_sched.h>
	50	#endif
	51	#include <linux/string.h>
	52	#include <linux/skbuff.h>
9c55e01c	53	#include <linux/splice.h>
1da177e4 LT	54	#include <linux/cache.h>
	55	#include <linux/rtnetlink.h>
	56	#include <linux/init.h>
716ea3a7	57	#include <linux/scatterlist.h>
1da177e4 LT	58
	59	#include <net/protocol.h>
	60	#include <net/dst.h>
	61	#include <net/sock.h>
	62	#include <net/checksum.h>
	63	#include <net/xfrm.h>
	64
	65	#include <asm/uaccess.h>
	66	#include <asm/system.h>
	67
a1f8e7f7 AV	68	#include "kmap_skb.h"
a1f8e7f7 AV	69
e18b890b CL	70	static struct kmem_cache *skbuff_head_cache __read_mostly;
e18b890b CL	71	static struct kmem_cache *skbuff_fclone_cache __read_mostly;
1da177e4	72
9c55e01c JA	73	static void sock_pipe_buf_release(struct pipe_inode_info *pipe,
	74	struct pipe_buffer *buf)
	75	{
8b9d3728	76	put_page(buf->page);
9c55e01c JA	77	}
	78
	79	static void sock_pipe_buf_get(struct pipe_inode_info *pipe,
	80	struct pipe_buffer *buf)
	81	{
8b9d3728	82	get_page(buf->page);
9c55e01c JA	83	}
	84
	85	static int sock_pipe_buf_steal(struct pipe_inode_info *pipe,
	86	struct pipe_buffer *buf)
	87	{
	88	return 1;
	89	}
	90
	91
	92	/* Pipe buffer operations for a socket. */
	93	static struct pipe_buf_operations sock_pipe_buf_ops = {
	94	.can_merge = 0,
	95	.map = generic_pipe_buf_map,
	96	.unmap = generic_pipe_buf_unmap,
	97	.confirm = generic_pipe_buf_confirm,
	98	.release = sock_pipe_buf_release,
	99	.steal = sock_pipe_buf_steal,
	100	.get = sock_pipe_buf_get,
	101	};
	102
1da177e4 LT	103	/*
	104	* Keep out-of-line to prevent kernel bloat.
	105	* __builtin_return_address is not used because it is not always
	106	* reliable.
	107	*/
	108
	109	/**
	110	* skb_over_panic - private function
	111	* @skb: buffer
	112	* @sz: size
	113	* @here: address
	114	*
	115	* Out of line support code for skb_put(). Not user callable.
	116	*/
	117	void skb_over_panic(struct sk_buff skb, int sz, void here)
	118	{
26095455	119	printk(KERN_EMERG "skb_over_panic: text:%p len:%d put:%d head:%p "
4305b541	120	"data:%p tail:%#lx end:%#lx dev:%s\n",
27a884dc	121	here, skb->len, sz, skb->head, skb->data,
4305b541	122	(unsigned long)skb->tail, (unsigned long)skb->end,
26095455	123	skb->dev ? skb->dev->name : "<NULL>");
1da177e4 LT	124	BUG();
	125	}
	126
	127	/**
	128	* skb_under_panic - private function
	129	* @skb: buffer
	130	* @sz: size
	131	* @here: address
	132	*
	133	* Out of line support code for skb_push(). Not user callable.
	134	*/
	135
	136	void skb_under_panic(struct sk_buff skb, int sz, void here)
	137	{
26095455	138	printk(KERN_EMERG "skb_under_panic: text:%p len:%d put:%d head:%p "
4305b541	139	"data:%p tail:%#lx end:%#lx dev:%s\n",
27a884dc	140	here, skb->len, sz, skb->head, skb->data,
4305b541	141	(unsigned long)skb->tail, (unsigned long)skb->end,
26095455	142	skb->dev ? skb->dev->name : "<NULL>");
1da177e4 LT	143	BUG();
	144	}
	145
	146	/* Allocate a new skbuff. We do this ourselves so we can fill in a few
	147	* 'private' fields and also do memory statistics to find all the
	148	* [BEEP] leaks.
	149	*
	150	*/
	151
	152	/**
d179cd12	153	* __alloc_skb - allocate a network buffer
1da177e4 LT	154	* @size: size to allocate
1da177e4 LT	155	* @gfp_mask: allocation mask
c83c2486 RD	156	* @fclone: allocate from fclone cache instead of head cache
c83c2486 RD	157	* and allocate a cloned (child) skb
b30973f8	158	* @node: numa node to allocate memory on
1da177e4 LT	159	*
	160	* Allocate a new &sk_buff. The returned buffer has no headroom and a
	161	* tail room of size bytes. The object has a reference count of one.
	162	* The return is the buffer. On a failure the return is %NULL.
	163	*
	164	* Buffers may only be allocated from interrupts using a @gfp_mask of
	165	* %GFP_ATOMIC.
	166	*/
dd0fc66f	167	struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
b30973f8	168	int fclone, int node)
1da177e4	169	{
e18b890b	170	struct kmem_cache *cache;
4947d3ef	171	struct skb_shared_info *shinfo;
1da177e4 LT	172	struct sk_buff *skb;
	173	u8 *data;
	174
8798b3fb HX	175	cache = fclone ? skbuff_fclone_cache : skbuff_head_cache;
8798b3fb HX	176
1da177e4	177	/* Get the HEAD */
b30973f8	178	skb = kmem_cache_alloc_node(cache, gfp_mask & ~__GFP_DMA, node);
1da177e4 LT	179	if (!skb)
	180	goto out;
	181
1da177e4	182	size = SKB_DATA_ALIGN(size);
b30973f8 CH	183	data = kmalloc_node_track_caller(size + sizeof(struct skb_shared_info),
b30973f8 CH	184	gfp_mask, node);
1da177e4 LT	185	if (!data)
	186	goto nodata;
	187
ca0605a7	188	/*
c8005785 JB	189	* Only clear those fields we need to clear, not those that we will
	190	* actually initialise below. Hence, don't put any more fields after
	191	* the tail pointer in struct sk_buff!
ca0605a7 ACM	192	*/
ca0605a7 ACM	193	memset(skb, 0, offsetof(struct sk_buff, tail));
1da177e4 LT	194	skb->truesize = size + sizeof(struct sk_buff);
	195	atomic_set(&skb->users, 1);
	196	skb->head = data;
	197	skb->data = data;
27a884dc	198	skb_reset_tail_pointer(skb);
4305b541	199	skb->end = skb->tail + size;
4947d3ef BL	200	/* make sure we initialize shinfo sequentially */
	201	shinfo = skb_shinfo(skb);
	202	atomic_set(&shinfo->dataref, 1);
	203	shinfo->nr_frags = 0;
7967168c HX	204	shinfo->gso_size = 0;
	205	shinfo->gso_segs = 0;
	206	shinfo->gso_type = 0;
4947d3ef BL	207	shinfo->ip6_frag_id = 0;
	208	shinfo->frag_list = NULL;
	209
d179cd12 DM	210	if (fclone) {
	211	struct sk_buff *child = skb + 1;
	212	atomic_t fclone_ref = (atomic_t ) (child + 1);
1da177e4	213
d179cd12 DM	214	skb->fclone = SKB_FCLONE_ORIG;
	215	atomic_set(fclone_ref, 1);
	216
	217	child->fclone = SKB_FCLONE_UNAVAILABLE;
	218	}
1da177e4 LT	219	out:
	220	return skb;
	221	nodata:
8798b3fb	222	kmem_cache_free(cache, skb);
1da177e4 LT	223	skb = NULL;
1da177e4 LT	224	goto out;
1da177e4 LT	225	}
1da177e4 LT	226
8af27456 CH	227	/**
	228	* __netdev_alloc_skb - allocate an skbuff for rx on a specific device
	229	* @dev: network device to receive on
	230	* @length: length to allocate
	231	* @gfp_mask: get_free_pages mask, passed to alloc_skb
	232	*
	233	* Allocate a new &sk_buff and assign it a usage count of one. The
	234	* buffer has unspecified headroom built in. Users should allocate
	235	* the headroom they think they need without accounting for the
	236	* built in space. The built in space is used for optimisations.
	237	*
	238	* %NULL is returned if there is no free memory.
	239	*/
	240	struct sk_buff __netdev_alloc_skb(struct net_device dev,
	241	unsigned int length, gfp_t gfp_mask)
	242	{
43cb76d9	243	int node = dev->dev.parent ? dev_to_node(dev->dev.parent) : -1;
8af27456 CH	244	struct sk_buff *skb;
8af27456 CH	245
4ec93edb	246	skb = __alloc_skb(length + NET_SKB_PAD, gfp_mask, 0, node);
7b2e497a	247	if (likely(skb)) {
8af27456	248	skb_reserve(skb, NET_SKB_PAD);
7b2e497a CH	249	skb->dev = dev;
7b2e497a CH	250	}
8af27456 CH	251	return skb;
8af27456 CH	252	}
1da177e4	253
654bed16 PZ	254	struct page __netdev_alloc_page(struct net_device dev, gfp_t gfp_mask)
	255	{
	256	int node = dev->dev.parent ? dev_to_node(dev->dev.parent) : -1;
	257	struct page *page;
	258
	259	page = alloc_pages_node(node, gfp_mask, 0);
	260	return page;
	261	}
	262	EXPORT_SYMBOL(__netdev_alloc_page);
	263
	264	void skb_add_rx_frag(struct sk_buff skb, int i, struct page page, int off,
	265	int size)
	266	{
	267	skb_fill_page_desc(skb, i, page, off, size);
	268	skb->len += size;
	269	skb->data_len += size;
	270	skb->truesize += size;
	271	}
	272	EXPORT_SYMBOL(skb_add_rx_frag);
	273
f58518e6 IJ	274	/**
	275	* dev_alloc_skb - allocate an skbuff for receiving
	276	* @length: length to allocate
	277	*
	278	* Allocate a new &sk_buff and assign it a usage count of one. The
	279	* buffer has unspecified headroom built in. Users should allocate
	280	* the headroom they think they need without accounting for the
	281	* built in space. The built in space is used for optimisations.
	282	*
	283	* %NULL is returned if there is no free memory. Although this function
	284	* allocates memory it can be called from an interrupt.
	285	*/
	286	struct sk_buff *dev_alloc_skb(unsigned int length)
	287	{
1483b874 DV	288	/*
1483b874 DV	289	* There is more code here than it seems:
a0f55e0e	290	* __dev_alloc_skb is an inline
1483b874	291	*/
f58518e6 IJ	292	return __dev_alloc_skb(length, GFP_ATOMIC);
	293	}
	294	EXPORT_SYMBOL(dev_alloc_skb);
	295
27b437c8	296	static void skb_drop_list(struct sk_buff **listp)
1da177e4	297	{
27b437c8	298	struct sk_buff list = listp;
1da177e4	299
27b437c8	300	*listp = NULL;
1da177e4 LT	301
	302	do {
	303	struct sk_buff *this = list;
	304	list = list->next;
	305	kfree_skb(this);
	306	} while (list);
	307	}
	308
27b437c8 HX	309	static inline void skb_drop_fraglist(struct sk_buff *skb)
	310	{
	311	skb_drop_list(&skb_shinfo(skb)->frag_list);
	312	}
	313
1da177e4 LT	314	static void skb_clone_fraglist(struct sk_buff *skb)
	315	{
	316	struct sk_buff *list;
	317
	318	for (list = skb_shinfo(skb)->frag_list; list; list = list->next)
	319	skb_get(list);
	320	}
	321
5bba1712	322	static void skb_release_data(struct sk_buff *skb)
1da177e4 LT	323	{
	324	if (!skb->cloned \|\|
	325	!atomic_sub_return(skb->nohdr ? (1 << SKB_DATAREF_SHIFT) + 1 : 1,
	326	&skb_shinfo(skb)->dataref)) {
	327	if (skb_shinfo(skb)->nr_frags) {
	328	int i;
	329	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
	330	put_page(skb_shinfo(skb)->frags[i].page);
	331	}
	332
	333	if (skb_shinfo(skb)->frag_list)
	334	skb_drop_fraglist(skb);
	335
	336	kfree(skb->head);
	337	}
	338	}
	339
	340	/*
	341	* Free an skbuff by memory without cleaning the state.
	342	*/
2d4baff8	343	static void kfree_skbmem(struct sk_buff *skb)
1da177e4	344	{
d179cd12 DM	345	struct sk_buff *other;
	346	atomic_t *fclone_ref;
	347
d179cd12 DM	348	switch (skb->fclone) {
	349	case SKB_FCLONE_UNAVAILABLE:
	350	kmem_cache_free(skbuff_head_cache, skb);
	351	break;
	352
	353	case SKB_FCLONE_ORIG:
	354	fclone_ref = (atomic_t *) (skb + 2);
	355	if (atomic_dec_and_test(fclone_ref))
	356	kmem_cache_free(skbuff_fclone_cache, skb);
	357	break;
	358
	359	case SKB_FCLONE_CLONE:
	360	fclone_ref = (atomic_t *) (skb + 1);
	361	other = skb - 1;
	362
	363	/* The clone portion is available for
	364	* fast-cloning again.
	365	*/
	366	skb->fclone = SKB_FCLONE_UNAVAILABLE;
	367
	368	if (atomic_dec_and_test(fclone_ref))
	369	kmem_cache_free(skbuff_fclone_cache, other);
	370	break;
3ff50b79	371	}
1da177e4 LT	372	}
1da177e4 LT	373
04a4bb55	374	static void skb_release_head_state(struct sk_buff *skb)
1da177e4	375	{
1da177e4 LT	376	dst_release(skb->dst);
	377	#ifdef CONFIG_XFRM
	378	secpath_put(skb->sp);
	379	#endif
9c2b3328 SH	380	if (skb->destructor) {
9c2b3328 SH	381	WARN_ON(in_irq());
1da177e4 LT	382	skb->destructor(skb);
1da177e4 LT	383	}
9fb9cbb1	384	#if defined(CONFIG_NF_CONNTRACK) \|\| defined(CONFIG_NF_CONNTRACK_MODULE)
5f79e0f9	385	nf_conntrack_put(skb->nfct);
9fb9cbb1 YK	386	nf_conntrack_put_reasm(skb->nfct_reasm);
9fb9cbb1 YK	387	#endif
1da177e4 LT	388	#ifdef CONFIG_BRIDGE_NETFILTER
	389	nf_bridge_put(skb->nf_bridge);
	390	#endif
1da177e4 LT	391	/* XXX: IS this still necessary? - JHS */
	392	#ifdef CONFIG_NET_SCHED
	393	skb->tc_index = 0;
	394	#ifdef CONFIG_NET_CLS_ACT
	395	skb->tc_verd = 0;
1da177e4 LT	396	#endif
1da177e4 LT	397	#endif
04a4bb55 LB	398	}
	399
	400	/* Free everything but the sk_buff shell. */
	401	static void skb_release_all(struct sk_buff *skb)
	402	{
	403	skb_release_head_state(skb);
2d4baff8 HX	404	skb_release_data(skb);
	405	}
	406
	407	/**
	408	* __kfree_skb - private function
	409	* @skb: buffer
	410	*
	411	* Free an sk_buff. Release anything attached to the buffer.
	412	* Clean the state. This is an internal helper function. Users should
	413	* always call kfree_skb
	414	*/
1da177e4	415
2d4baff8 HX	416	void __kfree_skb(struct sk_buff *skb)
	417	{
	418	skb_release_all(skb);
1da177e4 LT	419	kfree_skbmem(skb);
	420	}
	421