For the common, open coded 'skb->mac.raw = skb->data' operation, so that we can later turn skb->mac.raw into a offset, reducing the size of struct sk_buff in 64bit land while possibly keeping it as a pointer on 32bit. This one touches just the most simple case, next will handle the slightly more "complex" cases. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2041 lines
49 KiB
C
2041 lines
49 KiB
C
/*
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* Routines having to do with the 'struct sk_buff' memory handlers.
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*
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* Authors: Alan Cox <iiitac@pyr.swan.ac.uk>
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* Florian La Roche <rzsfl@rz.uni-sb.de>
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*
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* Version: $Id: skbuff.c,v 1.90 2001/11/07 05:56:19 davem Exp $
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*
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* Fixes:
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* Alan Cox : Fixed the worst of the load
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* balancer bugs.
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* Dave Platt : Interrupt stacking fix.
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* Richard Kooijman : Timestamp fixes.
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* Alan Cox : Changed buffer format.
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* Alan Cox : destructor hook for AF_UNIX etc.
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* Linus Torvalds : Better skb_clone.
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* Alan Cox : Added skb_copy.
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* Alan Cox : Added all the changed routines Linus
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* only put in the headers
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* Ray VanTassle : Fixed --skb->lock in free
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* Alan Cox : skb_copy copy arp field
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* Andi Kleen : slabified it.
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* Robert Olsson : Removed skb_head_pool
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*
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* NOTE:
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* The __skb_ routines should be called with interrupts
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* disabled, or you better be *real* sure that the operation is atomic
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* with respect to whatever list is being frobbed (e.g. via lock_sock()
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* or via disabling bottom half handlers, etc).
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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/*
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* The functions in this file will not compile correctly with gcc 2.4.x
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*/
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/interrupt.h>
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#include <linux/in.h>
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#include <linux/inet.h>
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#include <linux/slab.h>
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#include <linux/netdevice.h>
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#ifdef CONFIG_NET_CLS_ACT
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#include <net/pkt_sched.h>
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#endif
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#include <linux/string.h>
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#include <linux/skbuff.h>
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#include <linux/cache.h>
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#include <linux/rtnetlink.h>
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#include <linux/init.h>
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#include <net/protocol.h>
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#include <net/dst.h>
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#include <net/sock.h>
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#include <net/checksum.h>
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#include <net/xfrm.h>
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|
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#include <asm/uaccess.h>
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#include <asm/system.h>
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#include "kmap_skb.h"
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static struct kmem_cache *skbuff_head_cache __read_mostly;
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static struct kmem_cache *skbuff_fclone_cache __read_mostly;
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/*
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* Keep out-of-line to prevent kernel bloat.
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* __builtin_return_address is not used because it is not always
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* reliable.
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*/
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/**
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* skb_over_panic - private function
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* @skb: buffer
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* @sz: size
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* @here: address
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*
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* Out of line support code for skb_put(). Not user callable.
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*/
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void skb_over_panic(struct sk_buff *skb, int sz, void *here)
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{
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printk(KERN_EMERG "skb_over_panic: text:%p len:%d put:%d head:%p "
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"data:%p tail:%p end:%p dev:%s\n",
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here, skb->len, sz, skb->head, skb->data, skb->tail, skb->end,
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skb->dev ? skb->dev->name : "<NULL>");
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BUG();
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}
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|
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/**
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* skb_under_panic - private function
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* @skb: buffer
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* @sz: size
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* @here: address
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*
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* Out of line support code for skb_push(). Not user callable.
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*/
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void skb_under_panic(struct sk_buff *skb, int sz, void *here)
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{
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printk(KERN_EMERG "skb_under_panic: text:%p len:%d put:%d head:%p "
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"data:%p tail:%p end:%p dev:%s\n",
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here, skb->len, sz, skb->head, skb->data, skb->tail, skb->end,
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skb->dev ? skb->dev->name : "<NULL>");
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BUG();
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}
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void skb_truesize_bug(struct sk_buff *skb)
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{
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printk(KERN_ERR "SKB BUG: Invalid truesize (%u) "
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"len=%u, sizeof(sk_buff)=%Zd\n",
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skb->truesize, skb->len, sizeof(struct sk_buff));
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}
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EXPORT_SYMBOL(skb_truesize_bug);
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/* Allocate a new skbuff. We do this ourselves so we can fill in a few
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* 'private' fields and also do memory statistics to find all the
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* [BEEP] leaks.
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*
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*/
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/**
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* __alloc_skb - allocate a network buffer
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* @size: size to allocate
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* @gfp_mask: allocation mask
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* @fclone: allocate from fclone cache instead of head cache
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* and allocate a cloned (child) skb
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* @node: numa node to allocate memory on
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*
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* Allocate a new &sk_buff. The returned buffer has no headroom and a
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* tail room of size bytes. The object has a reference count of one.
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* The return is the buffer. On a failure the return is %NULL.
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*
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* Buffers may only be allocated from interrupts using a @gfp_mask of
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* %GFP_ATOMIC.
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*/
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struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
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int fclone, int node)
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{
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struct kmem_cache *cache;
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struct skb_shared_info *shinfo;
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struct sk_buff *skb;
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u8 *data;
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cache = fclone ? skbuff_fclone_cache : skbuff_head_cache;
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/* Get the HEAD */
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skb = kmem_cache_alloc_node(cache, gfp_mask & ~__GFP_DMA, node);
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if (!skb)
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goto out;
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/* Get the DATA. Size must match skb_add_mtu(). */
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size = SKB_DATA_ALIGN(size);
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data = kmalloc_node_track_caller(size + sizeof(struct skb_shared_info),
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gfp_mask, node);
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if (!data)
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goto nodata;
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memset(skb, 0, offsetof(struct sk_buff, truesize));
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skb->truesize = size + sizeof(struct sk_buff);
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atomic_set(&skb->users, 1);
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skb->head = data;
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skb->data = data;
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skb->tail = data;
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skb->end = data + size;
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/* make sure we initialize shinfo sequentially */
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shinfo = skb_shinfo(skb);
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atomic_set(&shinfo->dataref, 1);
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shinfo->nr_frags = 0;
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shinfo->gso_size = 0;
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shinfo->gso_segs = 0;
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shinfo->gso_type = 0;
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shinfo->ip6_frag_id = 0;
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shinfo->frag_list = NULL;
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if (fclone) {
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struct sk_buff *child = skb + 1;
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atomic_t *fclone_ref = (atomic_t *) (child + 1);
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skb->fclone = SKB_FCLONE_ORIG;
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atomic_set(fclone_ref, 1);
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child->fclone = SKB_FCLONE_UNAVAILABLE;
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}
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out:
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return skb;
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nodata:
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kmem_cache_free(cache, skb);
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skb = NULL;
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goto out;
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}
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/**
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* __netdev_alloc_skb - allocate an skbuff for rx on a specific device
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* @dev: network device to receive on
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* @length: length to allocate
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* @gfp_mask: get_free_pages mask, passed to alloc_skb
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*
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* Allocate a new &sk_buff and assign it a usage count of one. The
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* buffer has unspecified headroom built in. Users should allocate
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* the headroom they think they need without accounting for the
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* built in space. The built in space is used for optimisations.
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*
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* %NULL is returned if there is no free memory.
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*/
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struct sk_buff *__netdev_alloc_skb(struct net_device *dev,
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unsigned int length, gfp_t gfp_mask)
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{
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int node = dev->dev.parent ? dev_to_node(dev->dev.parent) : -1;
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struct sk_buff *skb;
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skb = __alloc_skb(length + NET_SKB_PAD, gfp_mask, 0, node);
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if (likely(skb)) {
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skb_reserve(skb, NET_SKB_PAD);
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skb->dev = dev;
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}
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return skb;
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}
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static void skb_drop_list(struct sk_buff **listp)
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{
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struct sk_buff *list = *listp;
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*listp = NULL;
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do {
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struct sk_buff *this = list;
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list = list->next;
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kfree_skb(this);
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} while (list);
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}
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static inline void skb_drop_fraglist(struct sk_buff *skb)
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{
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skb_drop_list(&skb_shinfo(skb)->frag_list);
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}
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static void skb_clone_fraglist(struct sk_buff *skb)
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{
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struct sk_buff *list;
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for (list = skb_shinfo(skb)->frag_list; list; list = list->next)
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skb_get(list);
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}
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static void skb_release_data(struct sk_buff *skb)
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{
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if (!skb->cloned ||
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!atomic_sub_return(skb->nohdr ? (1 << SKB_DATAREF_SHIFT) + 1 : 1,
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&skb_shinfo(skb)->dataref)) {
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if (skb_shinfo(skb)->nr_frags) {
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int i;
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for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
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put_page(skb_shinfo(skb)->frags[i].page);
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}
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if (skb_shinfo(skb)->frag_list)
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skb_drop_fraglist(skb);
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kfree(skb->head);
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}
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}
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/*
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* Free an skbuff by memory without cleaning the state.
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*/
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void kfree_skbmem(struct sk_buff *skb)
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{
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struct sk_buff *other;
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atomic_t *fclone_ref;
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skb_release_data(skb);
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switch (skb->fclone) {
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case SKB_FCLONE_UNAVAILABLE:
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kmem_cache_free(skbuff_head_cache, skb);
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break;
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case SKB_FCLONE_ORIG:
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fclone_ref = (atomic_t *) (skb + 2);
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if (atomic_dec_and_test(fclone_ref))
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kmem_cache_free(skbuff_fclone_cache, skb);
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break;
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case SKB_FCLONE_CLONE:
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fclone_ref = (atomic_t *) (skb + 1);
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other = skb - 1;
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/* The clone portion is available for
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* fast-cloning again.
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*/
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skb->fclone = SKB_FCLONE_UNAVAILABLE;
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if (atomic_dec_and_test(fclone_ref))
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kmem_cache_free(skbuff_fclone_cache, other);
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break;
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};
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}
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/**
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* __kfree_skb - private function
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* @skb: buffer
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*
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* Free an sk_buff. Release anything attached to the buffer.
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* Clean the state. This is an internal helper function. Users should
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* always call kfree_skb
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*/
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void __kfree_skb(struct sk_buff *skb)
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{
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dst_release(skb->dst);
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#ifdef CONFIG_XFRM
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secpath_put(skb->sp);
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#endif
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if (skb->destructor) {
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WARN_ON(in_irq());
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skb->destructor(skb);
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}
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#ifdef CONFIG_NETFILTER
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nf_conntrack_put(skb->nfct);
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#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
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nf_conntrack_put_reasm(skb->nfct_reasm);
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#endif
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#ifdef CONFIG_BRIDGE_NETFILTER
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nf_bridge_put(skb->nf_bridge);
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#endif
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#endif
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/* XXX: IS this still necessary? - JHS */
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#ifdef CONFIG_NET_SCHED
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skb->tc_index = 0;
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#ifdef CONFIG_NET_CLS_ACT
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skb->tc_verd = 0;
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#endif
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#endif
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kfree_skbmem(skb);
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}
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|
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/**
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* kfree_skb - free an sk_buff
|
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* @skb: buffer to free
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*
|
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* Drop a reference to the buffer and free it if the usage count has
|
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* hit zero.
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*/
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void kfree_skb(struct sk_buff *skb)
|
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{
|
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if (unlikely(!skb))
|
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return;
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if (likely(atomic_read(&skb->users) == 1))
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smp_rmb();
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else if (likely(!atomic_dec_and_test(&skb->users)))
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return;
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__kfree_skb(skb);
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}
|
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|
|
/**
|
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* skb_clone - duplicate an sk_buff
|
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* @skb: buffer to clone
|
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* @gfp_mask: allocation priority
|
|
*
|
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* Duplicate an &sk_buff. The new one is not owned by a socket. Both
|
|
* copies share the same packet data but not structure. The new
|
|
* buffer has a reference count of 1. If the allocation fails the
|
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* function returns %NULL otherwise the new buffer is returned.
|
|
*
|
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* If this function is called from an interrupt gfp_mask() must be
|
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* %GFP_ATOMIC.
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*/
|
|
|
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struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t gfp_mask)
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{
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struct sk_buff *n;
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n = skb + 1;
|
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if (skb->fclone == SKB_FCLONE_ORIG &&
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n->fclone == SKB_FCLONE_UNAVAILABLE) {
|
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atomic_t *fclone_ref = (atomic_t *) (n + 1);
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n->fclone = SKB_FCLONE_CLONE;
|
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atomic_inc(fclone_ref);
|
|
} else {
|
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n = kmem_cache_alloc(skbuff_head_cache, gfp_mask);
|
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if (!n)
|
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return NULL;
|
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n->fclone = SKB_FCLONE_UNAVAILABLE;
|
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}
|
|
|
|
#define C(x) n->x = skb->x
|
|
|
|
n->next = n->prev = NULL;
|
|
n->sk = NULL;
|
|
C(tstamp);
|
|
C(dev);
|
|
C(h);
|
|
C(nh);
|
|
C(mac);
|
|
C(dst);
|
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dst_clone(skb->dst);
|
|
C(sp);
|
|
#ifdef CONFIG_INET
|
|
secpath_get(skb->sp);
|
|
#endif
|
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memcpy(n->cb, skb->cb, sizeof(skb->cb));
|
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C(len);
|
|
C(data_len);
|
|
C(mac_len);
|
|
C(csum);
|
|
C(local_df);
|
|
n->cloned = 1;
|
|
n->nohdr = 0;
|
|
C(pkt_type);
|
|
C(ip_summed);
|
|
C(priority);
|
|
#if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE)
|
|
C(ipvs_property);
|
|
#endif
|
|
C(protocol);
|
|
n->destructor = NULL;
|
|
C(mark);
|
|
#ifdef CONFIG_NETFILTER
|
|
C(nfct);
|
|
nf_conntrack_get(skb->nfct);
|
|
C(nfctinfo);
|
|
#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
|
|
C(nfct_reasm);
|
|
nf_conntrack_get_reasm(skb->nfct_reasm);
|
|
#endif
|
|
#ifdef CONFIG_BRIDGE_NETFILTER
|
|
C(nf_bridge);
|
|
nf_bridge_get(skb->nf_bridge);
|
|
#endif
|
|
#endif /*CONFIG_NETFILTER*/
|
|
#ifdef CONFIG_NET_SCHED
|
|
C(tc_index);
|
|
#ifdef CONFIG_NET_CLS_ACT
|
|
n->tc_verd = SET_TC_VERD(skb->tc_verd,0);
|
|
n->tc_verd = CLR_TC_OK2MUNGE(n->tc_verd);
|
|
n->tc_verd = CLR_TC_MUNGED(n->tc_verd);
|
|
C(iif);
|
|
#endif
|
|
skb_copy_secmark(n, skb);
|
|
#endif
|
|
C(truesize);
|
|
atomic_set(&n->users, 1);
|
|
C(head);
|
|
C(data);
|
|
C(tail);
|
|
C(end);
|
|
|
|
atomic_inc(&(skb_shinfo(skb)->dataref));
|
|
skb->cloned = 1;
|
|
|
|
return n;
|
|
}
|
|
|
|
static void copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
|
|
{
|
|
/*
|
|
* Shift between the two data areas in bytes
|
|
*/
|
|
unsigned long offset = new->data - old->data;
|
|
|
|
new->sk = NULL;
|
|
new->dev = old->dev;
|
|
new->priority = old->priority;
|
|
new->protocol = old->protocol;
|
|
new->dst = dst_clone(old->dst);
|
|
#ifdef CONFIG_INET
|
|
new->sp = secpath_get(old->sp);
|
|
#endif
|
|
new->h.raw = old->h.raw + offset;
|
|
new->nh.raw = old->nh.raw + offset;
|
|
new->mac.raw = old->mac.raw + offset;
|
|
memcpy(new->cb, old->cb, sizeof(old->cb));
|
|
new->local_df = old->local_df;
|
|
new->fclone = SKB_FCLONE_UNAVAILABLE;
|
|
new->pkt_type = old->pkt_type;
|
|
new->tstamp = old->tstamp;
|
|
new->destructor = NULL;
|
|
new->mark = old->mark;
|
|
#ifdef CONFIG_NETFILTER
|
|
new->nfct = old->nfct;
|
|
nf_conntrack_get(old->nfct);
|
|
new->nfctinfo = old->nfctinfo;
|
|
#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
|
|
new->nfct_reasm = old->nfct_reasm;
|
|
nf_conntrack_get_reasm(old->nfct_reasm);
|
|
#endif
|
|
#if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE)
|
|
new->ipvs_property = old->ipvs_property;
|
|
#endif
|
|
#ifdef CONFIG_BRIDGE_NETFILTER
|
|
new->nf_bridge = old->nf_bridge;
|
|
nf_bridge_get(old->nf_bridge);
|
|
#endif
|
|
#endif
|
|
#ifdef CONFIG_NET_SCHED
|
|
#ifdef CONFIG_NET_CLS_ACT
|
|
new->tc_verd = old->tc_verd;
|
|
#endif
|
|
new->tc_index = old->tc_index;
|
|
#endif
|
|
skb_copy_secmark(new, old);
|
|
atomic_set(&new->users, 1);
|
|
skb_shinfo(new)->gso_size = skb_shinfo(old)->gso_size;
|
|
skb_shinfo(new)->gso_segs = skb_shinfo(old)->gso_segs;
|
|
skb_shinfo(new)->gso_type = skb_shinfo(old)->gso_type;
|
|
}
|
|
|
|
/**
|
|
* skb_copy - create private copy of an sk_buff
|
|
* @skb: buffer to copy
|
|
* @gfp_mask: allocation priority
|
|
*
|
|
* Make a copy of both an &sk_buff and its data. This is used when the
|
|
* caller wishes to modify the data and needs a private copy of the
|
|
* data to alter. Returns %NULL on failure or the pointer to the buffer
|
|
* on success. The returned buffer has a reference count of 1.
|
|
*
|
|
* As by-product this function converts non-linear &sk_buff to linear
|
|
* one, so that &sk_buff becomes completely private and caller is allowed
|
|
* to modify all the data of returned buffer. This means that this
|
|
* function is not recommended for use in circumstances when only
|
|
* header is going to be modified. Use pskb_copy() instead.
|
|
*/
|
|
|
|
struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t gfp_mask)
|
|
{
|
|
int headerlen = skb->data - skb->head;
|
|
/*
|
|
* Allocate the copy buffer
|
|
*/
|
|
struct sk_buff *n = alloc_skb(skb->end - skb->head + skb->data_len,
|
|
gfp_mask);
|
|
if (!n)
|
|
return NULL;
|
|
|
|
/* Set the data pointer */
|
|
skb_reserve(n, headerlen);
|
|
/* Set the tail pointer and length */
|
|
skb_put(n, skb->len);
|
|
n->csum = skb->csum;
|
|
n->ip_summed = skb->ip_summed;
|
|
|
|
if (skb_copy_bits(skb, -headerlen, n->head, headerlen + skb->len))
|
|
BUG();
|
|
|
|
copy_skb_header(n, skb);
|
|
return n;
|
|
}
|
|
|
|
|
|
/**
|
|
* pskb_copy - create copy of an sk_buff with private head.
|
|
* @skb: buffer to copy
|
|
* @gfp_mask: allocation priority
|
|
*
|
|
* Make a copy of both an &sk_buff and part of its data, located
|
|
* in header. Fragmented data remain shared. This is used when
|
|
* the caller wishes to modify only header of &sk_buff and needs
|
|
* private copy of the header to alter. Returns %NULL on failure
|
|
* or the pointer to the buffer on success.
|
|
* The returned buffer has a reference count of 1.
|
|
*/
|
|
|
|
struct sk_buff *pskb_copy(struct sk_buff *skb, gfp_t gfp_mask)
|
|
{
|
|
/*
|
|
* Allocate the copy buffer
|
|
*/
|
|
struct sk_buff *n = alloc_skb(skb->end - skb->head, gfp_mask);
|
|
|
|
if (!n)
|
|
goto out;
|
|
|
|
/* Set the data pointer */
|
|
skb_reserve(n, skb->data - skb->head);
|
|
/* Set the tail pointer and length */
|
|
skb_put(n, skb_headlen(skb));
|
|
/* Copy the bytes */
|
|
memcpy(n->data, skb->data, n->len);
|
|
n->csum = skb->csum;
|
|
n->ip_summed = skb->ip_summed;
|
|
|
|
n->truesize += skb->data_len;
|
|
n->data_len = skb->data_len;
|
|
n->len = skb->len;
|
|
|
|
if (skb_shinfo(skb)->nr_frags) {
|
|
int i;
|
|
|
|
for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
|
|
skb_shinfo(n)->frags[i] = skb_shinfo(skb)->frags[i];
|
|
get_page(skb_shinfo(n)->frags[i].page);
|
|
}
|
|
skb_shinfo(n)->nr_frags = i;
|
|
}
|
|
|
|
if (skb_shinfo(skb)->frag_list) {
|
|
skb_shinfo(n)->frag_list = skb_shinfo(skb)->frag_list;
|
|
skb_clone_fraglist(n);
|
|
}
|
|
|
|
copy_skb_header(n, skb);
|
|
out:
|
|
return n;
|
|
}
|
|
|
|
/**
|
|
* pskb_expand_head - reallocate header of &sk_buff
|
|
* @skb: buffer to reallocate
|
|
* @nhead: room to add at head
|
|
* @ntail: room to add at tail
|
|
* @gfp_mask: allocation priority
|
|
*
|
|
* Expands (or creates identical copy, if &nhead and &ntail are zero)
|
|
* header of skb. &sk_buff itself is not changed. &sk_buff MUST have
|
|
* reference count of 1. Returns zero in the case of success or error,
|
|
* if expansion failed. In the last case, &sk_buff is not changed.
|
|
*
|
|
* All the pointers pointing into skb header may change and must be
|
|
* reloaded after call to this function.
|
|
*/
|
|
|
|
int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail,
|
|
gfp_t gfp_mask)
|
|
{
|
|
int i;
|
|
u8 *data;
|
|
int size = nhead + (skb->end - skb->head) + ntail;
|
|
long off;
|
|
|
|
if (skb_shared(skb))
|
|
BUG();
|
|
|
|
size = SKB_DATA_ALIGN(size);
|
|
|
|
data = kmalloc(size + sizeof(struct skb_shared_info), gfp_mask);
|
|
if (!data)
|
|
goto nodata;
|
|
|
|
/* Copy only real data... and, alas, header. This should be
|
|
* optimized for the cases when header is void. */
|
|
memcpy(data + nhead, skb->head, skb->tail - skb->head);
|
|
memcpy(data + size, skb->end, sizeof(struct skb_shared_info));
|
|
|
|
for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
|
|
get_page(skb_shinfo(skb)->frags[i].page);
|
|
|
|
if (skb_shinfo(skb)->frag_list)
|
|
skb_clone_fraglist(skb);
|
|
|
|
skb_release_data(skb);
|
|
|
|
off = (data + nhead) - skb->head;
|
|
|
|
skb->head = data;
|
|
skb->end = data + size;
|
|
skb->data += off;
|
|
skb->tail += off;
|
|
skb->mac.raw += off;
|
|
skb->h.raw += off;
|
|
skb->nh.raw += off;
|
|
skb->cloned = 0;
|
|
skb->nohdr = 0;
|
|
atomic_set(&skb_shinfo(skb)->dataref, 1);
|
|
return 0;
|
|
|
|
nodata:
|
|
return -ENOMEM;
|
|
}
|
|
|
|
/* Make private copy of skb with writable head and some headroom */
|
|
|
|
struct sk_buff *skb_realloc_headroom(struct sk_buff *skb, unsigned int headroom)
|
|
{
|
|
struct sk_buff *skb2;
|
|
int delta = headroom - skb_headroom(skb);
|
|
|
|
if (delta <= 0)
|
|
skb2 = pskb_copy(skb, GFP_ATOMIC);
|
|
else {
|
|
skb2 = skb_clone(skb, GFP_ATOMIC);
|
|
if (skb2 && pskb_expand_head(skb2, SKB_DATA_ALIGN(delta), 0,
|
|
GFP_ATOMIC)) {
|
|
kfree_skb(skb2);
|
|
skb2 = NULL;
|
|
}
|
|
}
|
|
return skb2;
|
|
}
|
|
|
|
|
|
/**
|
|
* skb_copy_expand - copy and expand sk_buff
|
|
* @skb: buffer to copy
|
|
* @newheadroom: new free bytes at head
|
|
* @newtailroom: new free bytes at tail
|
|
* @gfp_mask: allocation priority
|
|
*
|
|
* Make a copy of both an &sk_buff and its data and while doing so
|
|
* allocate additional space.
|
|
*
|
|
* This is used when the caller wishes to modify the data and needs a
|
|
* private copy of the data to alter as well as more space for new fields.
|
|
* Returns %NULL on failure or the pointer to the buffer
|
|
* on success. The returned buffer has a reference count of 1.
|
|
*
|
|
* You must pass %GFP_ATOMIC as the allocation priority if this function
|
|
* is called from an interrupt.
|
|
*
|
|
* BUG ALERT: ip_summed is not copied. Why does this work? Is it used
|
|
* only by netfilter in the cases when checksum is recalculated? --ANK
|
|
*/
|
|
struct sk_buff *skb_copy_expand(const struct sk_buff *skb,
|
|
int newheadroom, int newtailroom,
|
|
gfp_t gfp_mask)
|
|
{
|
|
/*
|
|
* Allocate the copy buffer
|
|
*/
|
|
struct sk_buff *n = alloc_skb(newheadroom + skb->len + newtailroom,
|
|
gfp_mask);
|
|
int head_copy_len, head_copy_off;
|
|
|
|
if (!n)
|
|
return NULL;
|
|
|
|
skb_reserve(n, newheadroom);
|
|
|
|
/* Set the tail pointer and length */
|
|
skb_put(n, skb->len);
|
|
|
|
head_copy_len = skb_headroom(skb);
|
|
head_copy_off = 0;
|
|
if (newheadroom <= head_copy_len)
|
|
head_copy_len = newheadroom;
|
|
else
|
|
head_copy_off = newheadroom - head_copy_len;
|
|
|
|
/* Copy the linear header and data. */
|
|
if (skb_copy_bits(skb, -head_copy_len, n->head + head_copy_off,
|
|
skb->len + head_copy_len))
|
|
BUG();
|
|
|
|
copy_skb_header(n, skb);
|
|
|
|
return n;
|
|
}
|
|
|
|
/**
|
|
* skb_pad - zero pad the tail of an skb
|
|
* @skb: buffer to pad
|
|
* @pad: space to pad
|
|
*
|
|
* Ensure that a buffer is followed by a padding area that is zero
|
|
* filled. Used by network drivers which may DMA or transfer data
|
|
* beyond the buffer end onto the wire.
|
|
*
|
|
* May return error in out of memory cases. The skb is freed on error.
|
|
*/
|
|
|
|
int skb_pad(struct sk_buff *skb, int pad)
|
|
{
|
|
int err;
|
|
int ntail;
|
|
|
|
/* If the skbuff is non linear tailroom is always zero.. */
|
|
if (!skb_cloned(skb) && skb_tailroom(skb) >= pad) {
|
|
memset(skb->data+skb->len, 0, pad);
|
|
return 0;
|
|
}
|
|
|
|
ntail = skb->data_len + pad - (skb->end - skb->tail);
|
|
if (likely(skb_cloned(skb) || ntail > 0)) {
|
|
err = pskb_expand_head(skb, 0, ntail, GFP_ATOMIC);
|
|
if (unlikely(err))
|
|
goto free_skb;
|
|
}
|
|
|
|
/* FIXME: The use of this function with non-linear skb's really needs
|
|
* to be audited.
|
|
*/
|
|
err = skb_linearize(skb);
|
|
if (unlikely(err))
|
|
goto free_skb;
|
|
|
|
memset(skb->data + skb->len, 0, pad);
|
|
return 0;
|
|
|
|
free_skb:
|
|
kfree_skb(skb);
|
|
return err;
|
|
}
|
|
|
|
/* Trims skb to length len. It can change skb pointers.
|
|
*/
|
|
|
|
int ___pskb_trim(struct sk_buff *skb, unsigned int len)
|
|
{
|
|
struct sk_buff **fragp;
|
|
struct sk_buff *frag;
|
|
int offset = skb_headlen(skb);
|
|
int nfrags = skb_shinfo(skb)->nr_frags;
|
|
int i;
|
|
int err;
|
|
|
|
if (skb_cloned(skb) &&
|
|
unlikely((err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC))))
|
|
return err;
|
|
|
|
i = 0;
|
|
if (offset >= len)
|
|
goto drop_pages;
|
|
|
|
for (; i < nfrags; i++) {
|
|
int end = offset + skb_shinfo(skb)->frags[i].size;
|
|
|
|
if (end < len) {
|
|
offset = end;
|
|
continue;
|
|
}
|
|
|
|
skb_shinfo(skb)->frags[i++].size = len - offset;
|
|
|
|
drop_pages:
|
|
skb_shinfo(skb)->nr_frags = i;
|
|
|
|
for (; i < nfrags; i++)
|
|
put_page(skb_shinfo(skb)->frags[i].page);
|
|
|
|
if (skb_shinfo(skb)->frag_list)
|
|
skb_drop_fraglist(skb);
|
|
goto done;
|
|
}
|
|
|
|
for (fragp = &skb_shinfo(skb)->frag_list; (frag = *fragp);
|
|
fragp = &frag->next) {
|
|
int end = offset + frag->len;
|
|
|
|
if (skb_shared(frag)) {
|
|
struct sk_buff *nfrag;
|
|
|
|
nfrag = skb_clone(frag, GFP_ATOMIC);
|
|
if (unlikely(!nfrag))
|
|
return -ENOMEM;
|
|
|
|
nfrag->next = frag->next;
|
|
kfree_skb(frag);
|
|
frag = nfrag;
|
|
*fragp = frag;
|
|
}
|
|
|
|
if (end < len) {
|
|
offset = end;
|
|
continue;
|
|
}
|
|
|
|
if (end > len &&
|
|
unlikely((err = pskb_trim(frag, len - offset))))
|
|
return err;
|
|
|
|
if (frag->next)
|
|
skb_drop_list(&frag->next);
|
|
break;
|
|
}
|
|
|
|
done:
|
|
if (len > skb_headlen(skb)) {
|
|
skb->data_len -= skb->len - len;
|
|
skb->len = len;
|
|
} else {
|
|
skb->len = len;
|
|
skb->data_len = 0;
|
|
skb->tail = skb->data + len;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* __pskb_pull_tail - advance tail of skb header
|
|
* @skb: buffer to reallocate
|
|
* @delta: number of bytes to advance tail
|
|
*
|
|
* The function makes a sense only on a fragmented &sk_buff,
|
|
* it expands header moving its tail forward and copying necessary
|
|
* data from fragmented part.
|
|
*
|
|
* &sk_buff MUST have reference count of 1.
|
|
*
|
|
* Returns %NULL (and &sk_buff does not change) if pull failed
|
|
* or value of new tail of skb in the case of success.
|
|
*
|
|
* All the pointers pointing into skb header may change and must be
|
|
* reloaded after call to this function.
|
|
*/
|
|
|
|
/* Moves tail of skb head forward, copying data from fragmented part,
|
|
* when it is necessary.
|
|
* 1. It may fail due to malloc failure.
|
|
* 2. It may change skb pointers.
|
|
*
|
|
* It is pretty complicated. Luckily, it is called only in exceptional cases.
|
|
*/
|
|
unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta)
|
|
{
|
|
/* If skb has not enough free space at tail, get new one
|
|
* plus 128 bytes for future expansions. If we have enough
|
|
* room at tail, reallocate without expansion only if skb is cloned.
|
|
*/
|
|
int i, k, eat = (skb->tail + delta) - skb->end;
|
|
|
|
if (eat > 0 || skb_cloned(skb)) {
|
|
if (pskb_expand_head(skb, 0, eat > 0 ? eat + 128 : 0,
|
|
GFP_ATOMIC))
|
|
return NULL;
|
|
}
|
|
|
|
if (skb_copy_bits(skb, skb_headlen(skb), skb->tail, delta))
|
|
BUG();
|
|
|
|
/* Optimization: no fragments, no reasons to preestimate
|
|
* size of pulled pages. Superb.
|
|
*/
|
|
if (!skb_shinfo(skb)->frag_list)
|
|
goto pull_pages;
|
|
|
|
/* Estimate size of pulled pages. */
|
|
eat = delta;
|
|
for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
|
|
if (skb_shinfo(skb)->frags[i].size >= eat)
|
|
goto pull_pages;
|
|
eat -= skb_shinfo(skb)->frags[i].size;
|
|
}
|
|
|
|
/* If we need update frag list, we are in troubles.
|
|
* Certainly, it possible to add an offset to skb data,
|
|
* but taking into account that pulling is expected to
|
|
* be very rare operation, it is worth to fight against
|
|
* further bloating skb head and crucify ourselves here instead.
|
|
* Pure masohism, indeed. 8)8)
|
|
*/
|
|
if (eat) {
|
|
struct sk_buff *list = skb_shinfo(skb)->frag_list;
|
|
struct sk_buff *clone = NULL;
|
|
struct sk_buff *insp = NULL;
|
|
|
|
do {
|
|
BUG_ON(!list);
|
|
|
|
if (list->len <= eat) {
|
|
/* Eaten as whole. */
|
|
eat -= list->len;
|
|
list = list->next;
|
|
insp = list;
|
|
} else {
|
|
/* Eaten partially. */
|
|
|
|
if (skb_shared(list)) {
|
|
/* Sucks! We need to fork list. :-( */
|
|
clone = skb_clone(list, GFP_ATOMIC);
|
|
if (!clone)
|
|
return NULL;
|
|
insp = list->next;
|
|
list = clone;
|
|
} else {
|
|
/* This may be pulled without
|
|
* problems. */
|
|
insp = list;
|
|
}
|
|
if (!pskb_pull(list, eat)) {
|
|
if (clone)
|
|
kfree_skb(clone);
|
|
return NULL;
|
|
}
|
|
break;
|
|
}
|
|
} while (eat);
|
|
|
|
/* Free pulled out fragments. */
|
|
while ((list = skb_shinfo(skb)->frag_list) != insp) {
|
|
skb_shinfo(skb)->frag_list = list->next;
|
|
kfree_skb(list);
|
|
}
|
|
/* And insert new clone at head. */
|
|
if (clone) {
|
|
clone->next = list;
|
|
skb_shinfo(skb)->frag_list = clone;
|
|
}
|
|
}
|
|
/* Success! Now we may commit changes to skb data. */
|
|
|
|
pull_pages:
|
|
eat = delta;
|
|
k = 0;
|
|
for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
|
|
if (skb_shinfo(skb)->frags[i].size <= eat) {
|
|
put_page(skb_shinfo(skb)->frags[i].page);
|
|
eat -= skb_shinfo(skb)->frags[i].size;
|
|
} else {
|
|
skb_shinfo(skb)->frags[k] = skb_shinfo(skb)->frags[i];
|
|
if (eat) {
|
|
skb_shinfo(skb)->frags[k].page_offset += eat;
|
|
skb_shinfo(skb)->frags[k].size -= eat;
|
|
eat = 0;
|
|
}
|
|
k++;
|
|
}
|
|
}
|
|
skb_shinfo(skb)->nr_frags = k;
|
|
|
|
skb->tail += delta;
|
|
skb->data_len -= delta;
|
|
|
|
return skb->tail;
|
|
}
|
|
|
|
/* Copy some data bits from skb to kernel buffer. */
|
|
|
|
int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len)
|
|
{
|
|
int i, copy;
|
|
int start = skb_headlen(skb);
|
|
|
|
if (offset > (int)skb->len - len)
|
|
goto fault;
|
|
|
|
/* Copy header. */
|
|
if ((copy = start - offset) > 0) {
|
|
if (copy > len)
|
|
copy = len;
|
|
memcpy(to, skb->data + offset, copy);
|
|
if ((len -= copy) == 0)
|
|
return 0;
|
|
offset += copy;
|
|
to += copy;
|
|
}
|
|
|
|
for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
|
|
int end;
|
|
|
|
BUG_TRAP(start <= offset + len);
|
|
|
|
end = start + skb_shinfo(skb)->frags[i].size;
|
|
if ((copy = end - offset) > 0) {
|
|
u8 *vaddr;
|
|
|
|
if (copy > len)
|
|
copy = len;
|
|
|
|
vaddr = kmap_skb_frag(&skb_shinfo(skb)->frags[i]);
|
|
memcpy(to,
|
|
vaddr + skb_shinfo(skb)->frags[i].page_offset+
|
|
offset - start, copy);
|
|
kunmap_skb_frag(vaddr);
|
|
|
|
if ((len -= copy) == 0)
|
|
return 0;
|
|
offset += copy;
|
|
to += copy;
|
|
}
|
|
start = end;
|
|
}
|
|
|
|
if (skb_shinfo(skb)->frag_list) {
|
|
struct sk_buff *list = skb_shinfo(skb)->frag_list;
|
|
|
|
for (; list; list = list->next) {
|
|
int end;
|
|
|
|
BUG_TRAP(start <= offset + len);
|
|
|
|
end = start + list->len;
|
|
if ((copy = end - offset) > 0) {
|
|
if (copy > len)
|
|
copy = len;
|
|
if (skb_copy_bits(list, offset - start,
|
|
to, copy))
|
|
goto fault;
|
|
if ((len -= copy) == 0)
|
|
return 0;
|
|
offset += copy;
|
|
to += copy;
|
|
}
|
|
start = end;
|
|
}
|
|
}
|
|
if (!len)
|
|
return 0;
|
|
|
|
fault:
|
|
return -EFAULT;
|
|
}
|
|
|
|
/**
|
|
* skb_store_bits - store bits from kernel buffer to skb
|
|
* @skb: destination buffer
|
|
* @offset: offset in destination
|
|
* @from: source buffer
|
|
* @len: number of bytes to copy
|
|
*
|
|
* Copy the specified number of bytes from the source buffer to the
|
|
* destination skb. This function handles all the messy bits of
|
|
* traversing fragment lists and such.
|
|
*/
|
|
|
|
int skb_store_bits(const struct sk_buff *skb, int offset, void *from, int len)
|
|
{
|
|
int i, copy;
|
|
int start = skb_headlen(skb);
|
|
|
|
if (offset > (int)skb->len - len)
|
|
goto fault;
|
|
|
|
if ((copy = start - offset) > 0) {
|
|
if (copy > len)
|
|
copy = len;
|
|
memcpy(skb->data + offset, from, copy);
|
|
if ((len -= copy) == 0)
|
|
return 0;
|
|
offset += copy;
|
|
from += copy;
|
|
}
|
|
|
|
for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
|
|
skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
|
|
int end;
|
|
|
|
BUG_TRAP(start <= offset + len);
|
|
|
|
end = start + frag->size;
|
|
if ((copy = end - offset) > 0) {
|
|
u8 *vaddr;
|
|
|
|
if (copy > len)
|
|
copy = len;
|
|
|
|
vaddr = kmap_skb_frag(frag);
|
|
memcpy(vaddr + frag->page_offset + offset - start,
|
|
from, copy);
|
|
kunmap_skb_frag(vaddr);
|
|
|
|
if ((len -= copy) == 0)
|
|
return 0;
|
|
offset += copy;
|
|
from += copy;
|
|
}
|
|
start = end;
|
|
}
|
|
|
|
if (skb_shinfo(skb)->frag_list) {
|
|
struct sk_buff *list = skb_shinfo(skb)->frag_list;
|
|
|
|
for (; list; list = list->next) {
|
|
int end;
|
|
|
|
BUG_TRAP(start <= offset + len);
|
|
|
|
end = start + list->len;
|
|
if ((copy = end - offset) > 0) {
|
|
if (copy > len)
|
|
copy = len;
|
|
if (skb_store_bits(list, offset - start,
|
|
from, copy))
|
|
goto fault;
|
|
if ((len -= copy) == 0)
|
|
return 0;
|
|
offset += copy;
|
|
from += copy;
|
|
}
|
|
start = end;
|
|
}
|
|
}
|
|
if (!len)
|
|
return 0;
|
|
|
|
fault:
|
|
return -EFAULT;
|
|
}
|
|
|
|
EXPORT_SYMBOL(skb_store_bits);
|
|
|
|
/* Checksum skb data. */
|
|
|
|
__wsum skb_checksum(const struct sk_buff *skb, int offset,
|
|
int len, __wsum csum)
|
|
{
|
|
int start = skb_headlen(skb);
|
|
int i, copy = start - offset;
|
|
int pos = 0;
|
|
|
|
/* Checksum header. */
|
|
if (copy > 0) {
|
|
if (copy > len)
|
|
copy = len;
|
|
csum = csum_partial(skb->data + offset, copy, csum);
|
|
if ((len -= copy) == 0)
|
|
return csum;
|
|
offset += copy;
|
|
pos = copy;
|
|
}
|
|
|
|
for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
|
|
int end;
|
|
|
|
BUG_TRAP(start <= offset + len);
|
|
|
|
end = start + skb_shinfo(skb)->frags[i].size;
|
|
if ((copy = end - offset) > 0) {
|
|
__wsum csum2;
|
|
u8 *vaddr;
|
|
skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
|
|
|
|
if (copy > len)
|
|
copy = len;
|
|
vaddr = kmap_skb_frag(frag);
|
|
csum2 = csum_partial(vaddr + frag->page_offset +
|
|
offset - start, copy, 0);
|
|
kunmap_skb_frag(vaddr);
|
|
csum = csum_block_add(csum, csum2, pos);
|
|
if (!(len -= copy))
|
|
return csum;
|
|
offset += copy;
|
|
pos += copy;
|
|
}
|
|
start = end;
|
|
}
|
|
|
|
if (skb_shinfo(skb)->frag_list) {
|
|
struct sk_buff *list = skb_shinfo(skb)->frag_list;
|
|
|
|
for (; list; list = list->next) {
|
|
int end;
|
|
|
|
BUG_TRAP(start <= offset + len);
|
|
|
|
end = start + list->len;
|
|
if ((copy = end - offset) > 0) {
|
|
__wsum csum2;
|
|
if (copy > len)
|
|
copy = len;
|
|
csum2 = skb_checksum(list, offset - start,
|
|
copy, 0);
|
|
csum = csum_block_add(csum, csum2, pos);
|
|
if ((len -= copy) == 0)
|
|
return csum;
|
|
offset += copy;
|
|
pos += copy;
|
|
}
|
|
start = end;
|
|
}
|
|
}
|
|
BUG_ON(len);
|
|
|
|
return csum;
|
|
}
|
|
|
|
/* Both of above in one bottle. */
|
|
|
|
__wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset,
|
|
u8 *to, int len, __wsum csum)
|
|
{
|
|
int start = skb_headlen(skb);
|
|
int i, copy = start - offset;
|
|
int pos = 0;
|
|
|
|
/* Copy header. */
|
|
if (copy > 0) {
|
|
if (copy > len)
|
|
copy = len;
|
|
csum = csum_partial_copy_nocheck(skb->data + offset, to,
|
|
copy, csum);
|
|
if ((len -= copy) == 0)
|
|
return csum;
|
|
offset += copy;
|
|
to += copy;
|
|
pos = copy;
|
|
}
|
|
|
|
for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
|
|
int end;
|
|
|
|
BUG_TRAP(start <= offset + len);
|
|
|
|
end = start + skb_shinfo(skb)->frags[i].size;
|
|
if ((copy = end - offset) > 0) {
|
|
__wsum csum2;
|
|
u8 *vaddr;
|
|
skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
|
|
|
|
if (copy > len)
|
|
copy = len;
|
|
vaddr = kmap_skb_frag(frag);
|
|
csum2 = csum_partial_copy_nocheck(vaddr +
|
|
frag->page_offset +
|
|
offset - start, to,
|
|
copy, 0);
|
|
kunmap_skb_frag(vaddr);
|
|
csum = csum_block_add(csum, csum2, pos);
|
|
if (!(len -= copy))
|
|
return csum;
|
|
offset += copy;
|
|
to += copy;
|
|
pos += copy;
|
|
}
|
|
start = end;
|
|
}
|
|
|
|
if (skb_shinfo(skb)->frag_list) {
|
|
struct sk_buff *list = skb_shinfo(skb)->frag_list;
|
|
|
|
for (; list; list = list->next) {
|
|
__wsum csum2;
|
|
int end;
|
|
|
|
BUG_TRAP(start <= offset + len);
|
|
|
|
end = start + list->len;
|
|
if ((copy = end - offset) > 0) {
|
|
if (copy > len)
|
|
copy = len;
|
|
csum2 = skb_copy_and_csum_bits(list,
|
|
offset - start,
|
|
to, copy, 0);
|
|
csum = csum_block_add(csum, csum2, pos);
|
|
if ((len -= copy) == 0)
|
|
return csum;
|
|
offset += copy;
|
|
to += copy;
|
|
pos += copy;
|
|
}
|
|
start = end;
|
|
}
|
|
}
|
|
BUG_ON(len);
|
|
return csum;
|
|
}
|
|
|
|
void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to)
|
|
{
|
|
__wsum csum;
|
|
long csstart;
|
|
|
|
if (skb->ip_summed == CHECKSUM_PARTIAL)
|
|
csstart = skb->h.raw - skb->data;
|
|
else
|
|
csstart = skb_headlen(skb);
|
|
|
|
BUG_ON(csstart > skb_headlen(skb));
|
|
|
|
memcpy(to, skb->data, csstart);
|
|
|
|
csum = 0;
|
|
if (csstart != skb->len)
|
|
csum = skb_copy_and_csum_bits(skb, csstart, to + csstart,
|
|
skb->len - csstart, 0);
|
|
|
|
if (skb->ip_summed == CHECKSUM_PARTIAL) {
|
|
long csstuff = csstart + skb->csum_offset;
|
|
|
|
*((__sum16 *)(to + csstuff)) = csum_fold(csum);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* 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.
|
|
*/
|
|
|
|
struct sk_buff *skb_dequeue(struct sk_buff_head *list)
|
|
{
|
|
unsigned long flags;
|
|
struct sk_buff *result;
|
|
|
|
spin_lock_irqsave(&list->lock, flags);
|
|
result = __skb_dequeue(list);
|
|
spin_unlock_irqrestore(&list->lock, flags);
|
|
return result;
|
|
}
|
|
|
|
/**
|
|
* skb_dequeue_tail - remove from the tail of the queue
|
|
* @list: list to dequeue from
|
|
*
|
|
* Remove the tail 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.
|
|
*/
|
|
struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list)
|
|
{
|
|
unsigned 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;
|
|
}
|
|
|
|
/**
|
|
* 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 takes the list
|
|
* lock and is atomic with respect to other list locking functions.
|
|
*/
|
|
void skb_queue_purge(struct sk_buff_head *list)
|
|
{
|
|
struct sk_buff *skb;
|
|
while ((skb = skb_dequeue(list)) != NULL)
|
|
kfree_skb(skb);
|
|
}
|
|
|
|
/**
|
|
* 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.
|
|
*/
|
|
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 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.
|
|
*/
|
|
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_unlink - remove a buffer from a list
|
|
* @skb: buffer to remove
|
|
* @list: list to use
|
|
*
|
|
* Remove a packet from a list. The list locks are taken and this
|
|
* function is atomic with respect to other list locked calls
|
|
*
|
|
* You must know what list the SKB is on.
|
|
*/
|
|
void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
|
|
{
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&list->lock, flags);
|
|
__skb_unlink(skb, list);
|
|
spin_unlock_irqrestore(&list->lock, flags);
|
|
}
|
|
|
|
/**
|
|
* skb_append - append a buffer
|
|
* @old: buffer to insert after
|
|
* @newsk: buffer to insert
|
|
* @list: list to use
|
|
*
|
|
* 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.
|
|
*/
|
|
void skb_append(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list)
|
|
{
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&list->lock, flags);
|
|
__skb_append(old, newsk, list);
|
|
spin_unlock_irqrestore(&list->lock, flags);
|
|
}
|
|
|
|
|
|
/**
|
|
* skb_insert - insert a buffer
|
|
* @old: buffer to insert before
|
|
* @newsk: buffer to insert
|
|
* @list: list to use
|
|
*
|
|
* 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.
|
|
*/
|
|
void skb_insert(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list)
|
|
{
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&list->lock, flags);
|
|
__skb_insert(newsk, old->prev, old, list);
|
|
spin_unlock_irqrestore(&list->lock, flags);
|
|
}
|
|
|
|
#if 0
|
|
/*
|
|
* Tune the memory allocator for a new MTU size.
|
|
*/
|
|
void skb_add_mtu(int mtu)
|
|
{
|
|
/* Must match allocation in alloc_skb */
|
|
mtu = SKB_DATA_ALIGN(mtu) + sizeof(struct skb_shared_info);
|
|
|
|
kmem_add_cache_size(mtu);
|
|
}
|
|
#endif
|
|
|
|
static inline void skb_split_inside_header(struct sk_buff *skb,
|
|
struct sk_buff* skb1,
|
|
const u32 len, const int pos)
|
|
{
|
|
int i;
|
|
|
|
memcpy(skb_put(skb1, pos - len), skb->data + len, pos - len);
|
|
|
|
/* And move data appendix as is. */
|
|
for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
|
|
skb_shinfo(skb1)->frags[i] = skb_shinfo(skb)->frags[i];
|
|
|
|
skb_shinfo(skb1)->nr_frags = skb_shinfo(skb)->nr_frags;
|
|
skb_shinfo(skb)->nr_frags = 0;
|
|
skb1->data_len = skb->data_len;
|
|
skb1->len += skb1->data_len;
|
|
skb->data_len = 0;
|
|
skb->len = len;
|
|
skb->tail = skb->data + len;
|
|
}
|
|
|
|
static inline void skb_split_no_header(struct sk_buff *skb,
|
|
struct sk_buff* skb1,
|
|
const u32 len, int pos)
|
|
{
|
|
int i, k = 0;
|
|
const int nfrags = skb_shinfo(skb)->nr_frags;
|
|
|
|
skb_shinfo(skb)->nr_frags = 0;
|
|
skb1->len = skb1->data_len = skb->len - len;
|
|
skb->len = len;
|
|
skb->data_len = len - pos;
|
|
|
|
for (i = 0; i < nfrags; i++) {
|
|
int size = skb_shinfo(skb)->frags[i].size;
|
|
|
|
if (pos + size > len) {
|
|
skb_shinfo(skb1)->frags[k] = skb_shinfo(skb)->frags[i];
|
|
|
|
if (pos < len) {
|
|
/* Split frag.
|
|
* We have two variants in this case:
|
|
* 1. Move all the frag to the second
|
|
* part, if it is possible. F.e.
|
|
* this approach is mandatory for TUX,
|
|
* where splitting is expensive.
|
|
* 2. Split is accurately. We make this.
|
|
*/
|
|
get_page(skb_shinfo(skb)->frags[i].page);
|
|
skb_shinfo(skb1)->frags[0].page_offset += len - pos;
|
|
skb_shinfo(skb1)->frags[0].size -= len - pos;
|
|
skb_shinfo(skb)->frags[i].size = len - pos;
|
|
skb_shinfo(skb)->nr_frags++;
|
|
}
|
|
k++;
|
|
} else
|
|
skb_shinfo(skb)->nr_frags++;
|
|
pos += size;
|
|
}
|
|
skb_shinfo(skb1)->nr_frags = k;
|
|
}
|
|
|
|
/**
|
|
* skb_split - Split fragmented skb to two parts at length len.
|
|
* @skb: the buffer to split
|
|
* @skb1: the buffer to receive the second part
|
|
* @len: new length for skb
|
|
*/
|
|
void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len)
|
|
{
|
|
int pos = skb_headlen(skb);
|
|
|
|
if (len < pos) /* Split line is inside header. */
|
|
skb_split_inside_header(skb, skb1, len, pos);
|
|
else /* Second chunk has no header, nothing to copy. */
|
|
skb_split_no_header(skb, skb1, len, pos);
|
|
}
|
|
|
|
/**
|
|
* skb_prepare_seq_read - Prepare a sequential read of skb data
|
|
* @skb: the buffer to read
|
|
* @from: lower offset of data to be read
|
|
* @to: upper offset of data to be read
|
|
* @st: state variable
|
|
*
|
|
* Initializes the specified state variable. Must be called before
|
|
* invoking skb_seq_read() for the first time.
|
|
*/
|
|
void skb_prepare_seq_read(struct sk_buff *skb, unsigned int from,
|
|
unsigned int to, struct skb_seq_state *st)
|
|
{
|
|
st->lower_offset = from;
|
|
st->upper_offset = to;
|
|
st->root_skb = st->cur_skb = skb;
|
|
st->frag_idx = st->stepped_offset = 0;
|
|
st->frag_data = NULL;
|
|
}
|
|
|
|
/**
|
|
* skb_seq_read - Sequentially read skb data
|
|
* @consumed: number of bytes consumed by the caller so far
|
|
* @data: destination pointer for data to be returned
|
|
* @st: state variable
|
|
*
|
|
* Reads a block of skb data at &consumed relative to the
|
|
* lower offset specified to skb_prepare_seq_read(). Assigns
|
|
* the head of the data block to &data and returns the length
|
|
* of the block or 0 if the end of the skb data or the upper
|
|
* offset has been reached.
|
|
*
|
|
* The caller is not required to consume all of the data
|
|
* returned, i.e. &consumed is typically set to the number
|
|
* of bytes already consumed and the next call to
|
|
* skb_seq_read() will return the remaining part of the block.
|
|
*
|
|
* Note: The size of each block of data returned can be arbitary,
|
|
* this limitation is the cost for zerocopy seqeuental
|
|
* reads of potentially non linear data.
|
|
*
|
|
* Note: Fragment lists within fragments are not implemented
|
|
* at the moment, state->root_skb could be replaced with
|
|
* a stack for this purpose.
|
|
*/
|
|
unsigned int skb_seq_read(unsigned int consumed, const u8 **data,
|
|
struct skb_seq_state *st)
|
|
{
|
|
unsigned int block_limit, abs_offset = consumed + st->lower_offset;
|
|
skb_frag_t *frag;
|
|
|
|
if (unlikely(abs_offset >= st->upper_offset))
|
|
return 0;
|
|
|
|
next_skb:
|
|
block_limit = skb_headlen(st->cur_skb);
|
|
|
|
if (abs_offset < block_limit) {
|
|
*data = st->cur_skb->data + abs_offset;
|
|
return block_limit - abs_offset;
|
|
}
|
|
|
|
if (st->frag_idx == 0 && !st->frag_data)
|
|
st->stepped_offset += skb_headlen(st->cur_skb);
|
|
|
|
while (st->frag_idx < skb_shinfo(st->cur_skb)->nr_frags) {
|
|
frag = &skb_shinfo(st->cur_skb)->frags[st->frag_idx];
|
|
block_limit = frag->size + st->stepped_offset;
|
|
|
|
if (abs_offset < block_limit) {
|
|
if (!st->frag_data)
|
|
st->frag_data = kmap_skb_frag(frag);
|
|
|
|
*data = (u8 *) st->frag_data + frag->page_offset +
|
|
(abs_offset - st->stepped_offset);
|
|
|
|
return block_limit - abs_offset;
|
|
}
|
|
|
|
if (st->frag_data) {
|
|
kunmap_skb_frag(st->frag_data);
|
|
st->frag_data = NULL;
|
|
}
|
|
|
|
st->frag_idx++;
|
|
st->stepped_offset += frag->size;
|
|
}
|
|
|
|
if (st->cur_skb->next) {
|
|
st->cur_skb = st->cur_skb->next;
|
|
st->frag_idx = 0;
|
|
goto next_skb;
|
|
} else if (st->root_skb == st->cur_skb &&
|
|
skb_shinfo(st->root_skb)->frag_list) {
|
|
st->cur_skb = skb_shinfo(st->root_skb)->frag_list;
|
|
goto next_skb;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* skb_abort_seq_read - Abort a sequential read of skb data
|
|
* @st: state variable
|
|
*
|
|
* Must be called if skb_seq_read() was not called until it
|
|
* returned 0.
|
|
*/
|
|
void skb_abort_seq_read(struct skb_seq_state *st)
|
|
{
|
|
if (st->frag_data)
|
|
kunmap_skb_frag(st->frag_data);
|
|
}
|
|
|
|
#define TS_SKB_CB(state) ((struct skb_seq_state *) &((state)->cb))
|
|
|
|
static unsigned int skb_ts_get_next_block(unsigned int offset, const u8 **text,
|
|
struct ts_config *conf,
|
|
struct ts_state *state)
|
|
{
|
|
return skb_seq_read(offset, text, TS_SKB_CB(state));
|
|
}
|
|
|
|
static void skb_ts_finish(struct ts_config *conf, struct ts_state *state)
|
|
{
|
|
skb_abort_seq_read(TS_SKB_CB(state));
|
|
}
|
|
|
|
/**
|
|
* skb_find_text - Find a text pattern in skb data
|
|
* @skb: the buffer to look in
|
|
* @from: search offset
|
|
* @to: search limit
|
|
* @config: textsearch configuration
|
|
* @state: uninitialized textsearch state variable
|
|
*
|
|
* Finds a pattern in the skb data according to the specified
|
|
* textsearch configuration. Use textsearch_next() to retrieve
|
|
* subsequent occurrences of the pattern. Returns the offset
|
|
* to the first occurrence or UINT_MAX if no match was found.
|
|
*/
|
|
unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,
|
|
unsigned int to, struct ts_config *config,
|
|
struct ts_state *state)
|
|
{
|
|
unsigned int ret;
|
|
|
|
config->get_next_block = skb_ts_get_next_block;
|
|
config->finish = skb_ts_finish;
|
|
|
|
skb_prepare_seq_read(skb, from, to, TS_SKB_CB(state));
|
|
|
|
ret = textsearch_find(config, state);
|
|
return (ret <= to - from ? ret : UINT_MAX);
|
|
}
|
|
|
|
/**
|
|
* skb_append_datato_frags: - append the user data to a skb
|
|
* @sk: sock structure
|
|
* @skb: skb structure to be appened with user data.
|
|
* @getfrag: call back function to be used for getting the user data
|
|
* @from: pointer to user message iov
|
|
* @length: length of the iov message
|
|
*
|
|
* Description: This procedure append the user data in the fragment part
|
|
* of the skb if any page alloc fails user this procedure returns -ENOMEM
|
|
*/
|
|
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)
|
|
{
|
|
int frg_cnt = 0;
|
|
skb_frag_t *frag = NULL;
|
|
struct page *page = NULL;
|
|
int copy, left;
|
|
int offset = 0;
|
|
int ret;
|
|
|
|
do {
|
|
/* Return error if we don't have space for new frag */
|
|
frg_cnt = skb_shinfo(skb)->nr_frags;
|
|
if (frg_cnt >= MAX_SKB_FRAGS)
|
|
return -EFAULT;
|
|
|
|
/* allocate a new page for next frag */
|
|
page = alloc_pages(sk->sk_allocation, 0);
|
|
|
|
/* If alloc_page fails just return failure and caller will
|
|
* free previous allocated pages by doing kfree_skb()
|
|
*/
|
|
if (page == NULL)
|
|
return -ENOMEM;
|
|
|
|
/* initialize the next frag */
|
|
sk->sk_sndmsg_page = page;
|
|
sk->sk_sndmsg_off = 0;
|
|
skb_fill_page_desc(skb, frg_cnt, page, 0, 0);
|
|
skb->truesize += PAGE_SIZE;
|
|
atomic_add(PAGE_SIZE, &sk->sk_wmem_alloc);
|
|
|
|
/* get the new initialized frag */
|
|
frg_cnt = skb_shinfo(skb)->nr_frags;
|
|
frag = &skb_shinfo(skb)->frags[frg_cnt - 1];
|
|
|
|
/* copy the user data to page */
|
|
left = PAGE_SIZE - frag->page_offset;
|
|
copy = (length > left)? left : length;
|
|
|
|
ret = getfrag(from, (page_address(frag->page) +
|
|
frag->page_offset + frag->size),
|
|
offset, copy, 0, skb);
|
|
if (ret < 0)
|
|
return -EFAULT;
|
|
|
|
/* copy was successful so update the size parameters */
|
|
sk->sk_sndmsg_off += copy;
|
|
frag->size += copy;
|
|
skb->len += copy;
|
|
skb->data_len += copy;
|
|
offset += copy;
|
|
length -= copy;
|
|
|
|
} while (length > 0);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* skb_pull_rcsum - pull skb and update receive checksum
|
|
* @skb: buffer to update
|
|
* @start: start of data before pull
|
|
* @len: length of data pulled
|
|
*
|
|
* This function performs an skb_pull on the packet and updates
|
|
* update the CHECKSUM_COMPLETE checksum. It should be used on
|
|
* receive path processing instead of skb_pull unless you know
|
|
* that the checksum difference is zero (e.g., a valid IP header)
|
|
* or you are setting ip_summed to CHECKSUM_NONE.
|
|
*/
|
|
unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len)
|
|
{
|
|
BUG_ON(len > skb->len);
|
|
skb->len -= len;
|
|
BUG_ON(skb->len < skb->data_len);
|
|
skb_postpull_rcsum(skb, skb->data, len);
|
|
return skb->data += len;
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(skb_pull_rcsum);
|
|
|
|
/**
|
|
* skb_segment - Perform protocol segmentation on skb.
|
|
* @skb: buffer to segment
|
|
* @features: features for the output path (see dev->features)
|
|
*
|
|
* This function performs segmentation on the given skb. It returns
|
|
* the segment at the given position. It returns NULL if there are
|
|
* no more segments to generate, or when an error is encountered.
|
|
*/
|
|
struct sk_buff *skb_segment(struct sk_buff *skb, int features)
|
|
{
|
|
struct sk_buff *segs = NULL;
|
|
struct sk_buff *tail = NULL;
|
|
unsigned int mss = skb_shinfo(skb)->gso_size;
|
|
unsigned int doffset = skb->data - skb->mac.raw;
|
|
unsigned int offset = doffset;
|
|
unsigned int headroom;
|
|
unsigned int len;
|
|
int sg = features & NETIF_F_SG;
|
|
int nfrags = skb_shinfo(skb)->nr_frags;
|
|
int err = -ENOMEM;
|
|
int i = 0;
|
|
int pos;
|
|
|
|
__skb_push(skb, doffset);
|
|
headroom = skb_headroom(skb);
|
|
pos = skb_headlen(skb);
|
|
|
|
do {
|
|
struct sk_buff *nskb;
|
|
skb_frag_t *frag;
|
|
int hsize;
|
|
int k;
|
|
int size;
|
|
|
|
len = skb->len - offset;
|
|
if (len > mss)
|
|
len = mss;
|
|
|
|
hsize = skb_headlen(skb) - offset;
|
|
if (hsize < 0)
|
|
hsize = 0;
|
|
if (hsize > len || !sg)
|
|
hsize = len;
|
|
|
|
nskb = alloc_skb(hsize + doffset + headroom, GFP_ATOMIC);
|
|
if (unlikely(!nskb))
|
|
goto err;
|
|
|
|
if (segs)
|
|
tail->next = nskb;
|
|
else
|
|
segs = nskb;
|
|
tail = nskb;
|
|
|
|
nskb->dev = skb->dev;
|
|
nskb->priority = skb->priority;
|
|
nskb->protocol = skb->protocol;
|
|
nskb->dst = dst_clone(skb->dst);
|
|
memcpy(nskb->cb, skb->cb, sizeof(skb->cb));
|
|
nskb->pkt_type = skb->pkt_type;
|
|
nskb->mac_len = skb->mac_len;
|
|
|
|
skb_reserve(nskb, headroom);
|
|
skb_reset_mac_header(nskb);
|
|
nskb->nh.raw = nskb->data + skb->mac_len;
|
|
nskb->h.raw = nskb->nh.raw + (skb->h.raw - skb->nh.raw);
|
|
memcpy(skb_put(nskb, doffset), skb->data, doffset);
|
|
|
|
if (!sg) {
|
|
nskb->csum = skb_copy_and_csum_bits(skb, offset,
|
|
skb_put(nskb, len),
|
|
len, 0);
|
|
continue;
|
|
}
|
|
|
|
frag = skb_shinfo(nskb)->frags;
|
|
k = 0;
|
|
|
|
nskb->ip_summed = CHECKSUM_PARTIAL;
|
|
nskb->csum = skb->csum;
|
|
memcpy(skb_put(nskb, hsize), skb->data + offset, hsize);
|
|
|
|
while (pos < offset + len) {
|
|
BUG_ON(i >= nfrags);
|
|
|
|
*frag = skb_shinfo(skb)->frags[i];
|
|
get_page(frag->page);
|
|
size = frag->size;
|
|
|
|
if (pos < offset) {
|
|
frag->page_offset += offset - pos;
|
|
frag->size -= offset - pos;
|
|
}
|
|
|
|
k++;
|
|
|
|
if (pos + size <= offset + len) {
|
|
i++;
|
|
pos += size;
|
|
} else {
|
|
frag->size -= pos + size - (offset + len);
|
|
break;
|
|
}
|
|
|
|
frag++;
|
|
}
|
|
|
|
skb_shinfo(nskb)->nr_frags = k;
|
|
nskb->data_len = len - hsize;
|
|
nskb->len += nskb->data_len;
|
|
nskb->truesize += nskb->data_len;
|
|
} while ((offset += len) < skb->len);
|
|
|
|
return segs;
|
|
|
|
err:
|
|
while ((skb = segs)) {
|
|
segs = skb->next;
|
|
kfree_skb(skb);
|
|
}
|
|
return ERR_PTR(err);
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(skb_segment);
|
|
|
|
void __init skb_init(void)
|
|
{
|
|
skbuff_head_cache = kmem_cache_create("skbuff_head_cache",
|
|
sizeof(struct sk_buff),
|
|
0,
|
|
SLAB_HWCACHE_ALIGN|SLAB_PANIC,
|
|
NULL, NULL);
|
|
skbuff_fclone_cache = kmem_cache_create("skbuff_fclone_cache",
|
|
(2*sizeof(struct sk_buff)) +
|
|
sizeof(atomic_t),
|
|
0,
|
|
SLAB_HWCACHE_ALIGN|SLAB_PANIC,
|
|
NULL, NULL);
|
|
}
|
|
|
|
EXPORT_SYMBOL(___pskb_trim);
|
|
EXPORT_SYMBOL(__kfree_skb);
|
|
EXPORT_SYMBOL(kfree_skb);
|
|
EXPORT_SYMBOL(__pskb_pull_tail);
|
|
EXPORT_SYMBOL(__alloc_skb);
|
|
EXPORT_SYMBOL(__netdev_alloc_skb);
|
|
EXPORT_SYMBOL(pskb_copy);
|
|
EXPORT_SYMBOL(pskb_expand_head);
|
|
EXPORT_SYMBOL(skb_checksum);
|
|
EXPORT_SYMBOL(skb_clone);
|
|
EXPORT_SYMBOL(skb_clone_fraglist);
|
|
EXPORT_SYMBOL(skb_copy);
|
|
EXPORT_SYMBOL(skb_copy_and_csum_bits);
|
|
EXPORT_SYMBOL(skb_copy_and_csum_dev);
|
|
EXPORT_SYMBOL(skb_copy_bits);
|
|
EXPORT_SYMBOL(skb_copy_expand);
|
|
EXPORT_SYMBOL(skb_over_panic);
|
|
EXPORT_SYMBOL(skb_pad);
|
|
EXPORT_SYMBOL(skb_realloc_headroom);
|
|
EXPORT_SYMBOL(skb_under_panic);
|
|
EXPORT_SYMBOL(skb_dequeue);
|
|
EXPORT_SYMBOL(skb_dequeue_tail);
|
|
EXPORT_SYMBOL(skb_insert);
|
|
EXPORT_SYMBOL(skb_queue_purge);
|
|
EXPORT_SYMBOL(skb_queue_head);
|
|
EXPORT_SYMBOL(skb_queue_tail);
|
|
EXPORT_SYMBOL(skb_unlink);
|
|
EXPORT_SYMBOL(skb_append);
|
|
EXPORT_SYMBOL(skb_split);
|
|
EXPORT_SYMBOL(skb_prepare_seq_read);
|
|
EXPORT_SYMBOL(skb_seq_read);
|
|
EXPORT_SYMBOL(skb_abort_seq_read);
|
|
EXPORT_SYMBOL(skb_find_text);
|
|
EXPORT_SYMBOL(skb_append_datato_frags);
|