1 | /* |
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2 | * Routines having to do with the 'struct sk_buff' memory handlers. |
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3 | * |
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4 | * Authors: Alan Cox <iiitac@pyr.swan.ac.uk> |
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5 | * Florian La Roche <rzsfl@rz.uni-sb.de> |
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6 | * |
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7 | * Version: $Id: skbuff.c,v 1.90 2001/11/07 05:56:19 davem Exp $ |
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8 | * |
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9 | * Fixes: |
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10 | * Alan Cox : Fixed the worst of the load |
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11 | * balancer bugs. |
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12 | * Dave Platt : Interrupt stacking fix. |
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13 | * Richard Kooijman : Timestamp fixes. |
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14 | * Alan Cox : Changed buffer format. |
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15 | * Alan Cox : destructor hook for AF_UNIX etc. |
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16 | * Linus Torvalds : Better skb_clone. |
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17 | * Alan Cox : Added skb_copy. |
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18 | * Alan Cox : Added all the changed routines Linus |
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19 | * only put in the headers |
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20 | * Ray VanTassle : Fixed --skb->lock in free |
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21 | * Alan Cox : skb_copy copy arp field |
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22 | * Andi Kleen : slabified it. |
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23 | * Robert Olsson : Removed skb_head_pool |
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24 | * |
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25 | * NOTE: |
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26 | * The __skb_ routines should be called with interrupts |
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27 | * disabled, or you better be *real* sure that the operation is atomic |
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28 | * with respect to whatever list is being frobbed (e.g. via lock_sock() |
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29 | * or via disabling bottom half handlers, etc). |
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30 | * |
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31 | * This program is free software; you can redistribute it and/or |
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32 | * modify it under the terms of the GNU General Public License |
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33 | * as published by the Free Software Foundation; either version |
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34 | * 2 of the License, or (at your option) any later version. |
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35 | */ |
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36 | |
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37 | /* |
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38 | * The functions in this file will not compile correctly with gcc 2.4.x |
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39 | */ |
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40 | |
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41 | #include <linux/module.h> |
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42 | #include <linux/types.h> |
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43 | #include <linux/kernel.h> |
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44 | #include <linux/sched.h> |
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45 | #include <linux/mm.h> |
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46 | #include <linux/interrupt.h> |
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47 | #include <linux/in.h> |
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48 | #include <linux/inet.h> |
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49 | #include <linux/slab.h> |
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50 | #include <linux/netdevice.h> |
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51 | #ifdef CONFIG_NET_CLS_ACT |
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52 | #include <net/pkt_sched.h> |
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53 | #endif |
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54 | #include <linux/string.h> |
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55 | #include <linux/skbuff.h> |
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56 | #include <linux/cache.h> |
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57 | #include <linux/rtnetlink.h> |
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58 | #include <linux/init.h> |
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59 | #include <linux/highmem.h> |
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60 | |
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61 | #include <net/protocol.h> |
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62 | #include <net/dst.h> |
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63 | #include <net/sock.h> |
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64 | #include <net/checksum.h> |
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65 | #include <net/xfrm.h> |
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66 | |
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67 | #include <asm/uaccess.h> |
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68 | #include <asm/system.h> |
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69 | |
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70 | static kmem_cache_t *skbuff_head_cache __read_mostly; |
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71 | static kmem_cache_t *skbuff_fclone_cache __read_mostly; |
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72 | |
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73 | /* |
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74 | * Keep out-of-line to prevent kernel bloat. |
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75 | * __builtin_return_address is not used because it is not always |
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76 | * reliable. |
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77 | */ |
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78 | |
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79 | /** |
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80 | * skb_over_panic - private function |
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81 | * @skb: buffer |
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82 | * @sz: size |
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83 | * @here: address |
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84 | * |
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85 | * Out of line support code for skb_put(). Not user callable. |
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86 | */ |
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87 | void skb_over_panic(struct sk_buff *skb, int sz, void *here) |
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88 | { |
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89 | printk(KERN_EMERG "skb_over_panic: text:%p len:%d put:%d head:%p " |
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90 | "data:%p tail:%p end:%p dev:%s\n", |
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91 | here, skb->len, sz, skb->head, skb->data, skb->tail, skb->end, |
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92 | skb->dev ? skb->dev->name : "<NULL>"); |
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93 | BUG(); |
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94 | } |
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95 | |
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96 | /** |
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97 | * skb_under_panic - private function |
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98 | * @skb: buffer |
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99 | * @sz: size |
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100 | * @here: address |
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101 | * |
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102 | * Out of line support code for skb_push(). Not user callable. |
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103 | */ |
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104 | |
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105 | void skb_under_panic(struct sk_buff *skb, int sz, void *here) |
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106 | { |
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107 | printk(KERN_EMERG "skb_under_panic: text:%p len:%d put:%d head:%p " |
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108 | "data:%p tail:%p end:%p dev:%s\n", |
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109 | here, skb->len, sz, skb->head, skb->data, skb->tail, skb->end, |
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110 | skb->dev ? skb->dev->name : "<NULL>"); |
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111 | BUG(); |
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112 | } |
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113 | |
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114 | void skb_truesize_bug(struct sk_buff *skb) |
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115 | { |
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116 | printk(KERN_ERR "SKB BUG: Invalid truesize (%u) " |
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117 | "len=%u, sizeof(sk_buff)=%Zd\n", |
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118 | skb->truesize, skb->len, sizeof(struct sk_buff)); |
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119 | } |
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120 | EXPORT_SYMBOL(skb_truesize_bug); |
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121 | |
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122 | /* Allocate a new skbuff. We do this ourselves so we can fill in a few |
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123 | * 'private' fields and also do memory statistics to find all the |
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124 | * [BEEP] leaks. |
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125 | * |
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126 | */ |
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127 | |
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128 | /** |
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129 | * __alloc_skb - allocate a network buffer |
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130 | * @size: size to allocate |
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131 | * @gfp_mask: allocation mask |
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132 | * @fclone: allocate from fclone cache instead of head cache |
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133 | * and allocate a cloned (child) skb |
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134 | * |
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135 | * Allocate a new &sk_buff. The returned buffer has no headroom and a |
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136 | * tail room of size bytes. The object has a reference count of one. |
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137 | * The return is the buffer. On a failure the return is %NULL. |
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138 | * |
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139 | * Buffers may only be allocated from interrupts using a @gfp_mask of |
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140 | * %GFP_ATOMIC. |
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141 | */ |
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142 | struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask, |
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143 | int fclone) |
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144 | { |
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145 | kmem_cache_t *cache; |
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146 | struct skb_shared_info *shinfo; |
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147 | struct sk_buff *skb; |
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148 | u8 *data; |
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149 | |
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150 | cache = fclone ? skbuff_fclone_cache : skbuff_head_cache; |
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151 | |
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152 | /* Get the HEAD */ |
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153 | skb = kmem_cache_alloc(cache, gfp_mask & ~__GFP_DMA); |
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154 | if (!skb) |
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155 | goto out; |
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156 | |
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157 | /* Get the DATA. Size must match skb_add_mtu(). */ |
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158 | size = SKB_DATA_ALIGN(size); |
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159 | data = ____kmalloc(size + sizeof(struct skb_shared_info), gfp_mask); |
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160 | if (!data) |
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161 | goto nodata; |
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162 | |
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163 | memset(skb, 0, offsetof(struct sk_buff, truesize)); |
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164 | skb->truesize = size + sizeof(struct sk_buff); |
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165 | atomic_set(&skb->users, 1); |
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166 | skb->head = data; |
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167 | skb->data = data; |
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168 | skb->tail = data; |
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169 | skb->end = data + size; |
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170 | /* make sure we initialize shinfo sequentially */ |
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171 | shinfo = skb_shinfo(skb); |
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172 | atomic_set(&shinfo->dataref, 1); |
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173 | shinfo->nr_frags = 0; |
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174 | shinfo->gso_size = 0; |
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175 | shinfo->gso_segs = 0; |
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176 | shinfo->gso_type = 0; |
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177 | shinfo->ip6_frag_id = 0; |
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178 | shinfo->frag_list = NULL; |
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179 | |
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180 | if (fclone) { |
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181 | struct sk_buff *child = skb + 1; |
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182 | atomic_t *fclone_ref = (atomic_t *) (child + 1); |
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183 | |
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184 | skb->fclone = SKB_FCLONE_ORIG; |
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185 | atomic_set(fclone_ref, 1); |
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186 | |
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187 | child->fclone = SKB_FCLONE_UNAVAILABLE; |
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188 | } |
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189 | out: |
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190 | return skb; |
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191 | nodata: |
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192 | kmem_cache_free(cache, skb); |
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193 | skb = NULL; |
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194 | goto out; |
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195 | } |
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196 | |
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197 | /** |
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198 | * alloc_skb_from_cache - allocate a network buffer |
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199 | * @cp: kmem_cache from which to allocate the data area |
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200 | * (object size must be big enough for @size bytes + skb overheads) |
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201 | * @size: size to allocate |
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202 | * @gfp_mask: allocation mask |
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203 | * |
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204 | * Allocate a new &sk_buff. The returned buffer has no headroom and |
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205 | * tail room of size bytes. The object has a reference count of one. |
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206 | * The return is the buffer. On a failure the return is %NULL. |
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207 | * |
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208 | * Buffers may only be allocated from interrupts using a @gfp_mask of |
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209 | * %GFP_ATOMIC. |
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210 | */ |
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211 | struct sk_buff *alloc_skb_from_cache(kmem_cache_t *cp, |
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212 | unsigned int size, |
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213 | gfp_t gfp_mask) |
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214 | { |
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215 | struct sk_buff *skb; |
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216 | u8 *data; |
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217 | |
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218 | /* Get the HEAD */ |
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219 | skb = kmem_cache_alloc(skbuff_head_cache, |
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220 | gfp_mask & ~__GFP_DMA); |
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221 | if (!skb) |
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222 | goto out; |
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223 | |
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224 | /* Get the DATA. */ |
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225 | size = SKB_DATA_ALIGN(size); |
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226 | data = kmem_cache_alloc(cp, gfp_mask); |
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227 | if (!data) |
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228 | goto nodata; |
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229 | |
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230 | memset(skb, 0, offsetof(struct sk_buff, truesize)); |
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231 | skb->truesize = size + sizeof(struct sk_buff); |
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232 | atomic_set(&skb->users, 1); |
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233 | skb->head = data; |
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234 | skb->data = data; |
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235 | skb->tail = data; |
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236 | skb->end = data + size; |
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237 | |
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238 | atomic_set(&(skb_shinfo(skb)->dataref), 1); |
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239 | skb_shinfo(skb)->nr_frags = 0; |
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240 | skb_shinfo(skb)->gso_size = 0; |
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241 | skb_shinfo(skb)->gso_segs = 0; |
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242 | skb_shinfo(skb)->gso_type = 0; |
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243 | skb_shinfo(skb)->ip6_frag_id = 0; |
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244 | skb_shinfo(skb)->frag_list = NULL; |
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245 | out: |
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246 | return skb; |
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247 | nodata: |
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248 | kmem_cache_free(skbuff_head_cache, skb); |
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249 | skb = NULL; |
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250 | goto out; |
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251 | } |
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252 | |
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253 | /** |
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254 | * __netdev_alloc_skb - allocate an skbuff for rx on a specific device |
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255 | * @dev: network device to receive on |
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256 | * @length: length to allocate |
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257 | * @gfp_mask: get_free_pages mask, passed to alloc_skb |
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258 | * |
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259 | * Allocate a new &sk_buff and assign it a usage count of one. The |
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260 | * buffer has unspecified headroom built in. Users should allocate |
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261 | * the headroom they think they need without accounting for the |
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262 | * built in space. The built in space is used for optimisations. |
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263 | * |
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264 | * %NULL is returned if there is no free memory. |
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265 | */ |
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266 | struct sk_buff *__netdev_alloc_skb(struct net_device *dev, |
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267 | unsigned int length, gfp_t gfp_mask) |
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268 | { |
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269 | struct sk_buff *skb; |
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270 | |
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271 | skb = alloc_skb(length + NET_SKB_PAD, gfp_mask); |
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272 | if (likely(skb)) { |
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273 | skb_reserve(skb, NET_SKB_PAD); |
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274 | skb->dev = dev; |
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275 | } |
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276 | return skb; |
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277 | } |
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278 | |
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279 | static void skb_drop_list(struct sk_buff **listp) |
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280 | { |
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281 | struct sk_buff *list = *listp; |
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282 | |
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283 | *listp = NULL; |
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284 | |
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285 | do { |
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286 | struct sk_buff *this = list; |
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287 | list = list->next; |
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288 | kfree_skb(this); |
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289 | } while (list); |
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290 | } |
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291 | |
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292 | static inline void skb_drop_fraglist(struct sk_buff *skb) |
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293 | { |
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294 | skb_drop_list(&skb_shinfo(skb)->frag_list); |
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295 | } |
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296 | |
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297 | static void skb_clone_fraglist(struct sk_buff *skb) |
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298 | { |
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299 | struct sk_buff *list; |
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300 | |
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301 | for (list = skb_shinfo(skb)->frag_list; list; list = list->next) |
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302 | skb_get(list); |
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303 | } |
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304 | |
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305 | static void skb_release_data(struct sk_buff *skb) |
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306 | { |
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307 | if (!skb->cloned || |
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308 | !atomic_sub_return(skb->nohdr ? (1 << SKB_DATAREF_SHIFT) + 1 : 1, |
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309 | &skb_shinfo(skb)->dataref)) { |
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310 | if (skb_shinfo(skb)->nr_frags) { |
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311 | int i; |
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312 | for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) |
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313 | put_page(skb_shinfo(skb)->frags[i].page); |
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314 | } |
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315 | |
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316 | if (skb_shinfo(skb)->frag_list) |
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317 | skb_drop_fraglist(skb); |
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318 | |
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319 | kfree(skb->head); |
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320 | } |
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321 | } |
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322 | |
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323 | /* |
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324 | * Free an skbuff by memory without cleaning the state. |
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325 | */ |
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326 | void kfree_skbmem(struct sk_buff *skb) |
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327 | { |
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328 | struct sk_buff *other; |
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329 | atomic_t *fclone_ref; |
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330 | |
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331 | skb_release_data(skb); |
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332 | switch (skb->fclone) { |
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333 | case SKB_FCLONE_UNAVAILABLE: |
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334 | kmem_cache_free(skbuff_head_cache, skb); |
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335 | break; |
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336 | |
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337 | case SKB_FCLONE_ORIG: |
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338 | fclone_ref = (atomic_t *) (skb + 2); |
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339 | if (atomic_dec_and_test(fclone_ref)) |
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340 | kmem_cache_free(skbuff_fclone_cache, skb); |
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341 | break; |
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342 | |
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343 | case SKB_FCLONE_CLONE: |
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344 | fclone_ref = (atomic_t *) (skb + 1); |
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345 | other = skb - 1; |
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346 | |
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347 | /* The clone portion is available for |
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348 | * fast-cloning again. |
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349 | */ |
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350 | skb->fclone = SKB_FCLONE_UNAVAILABLE; |
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351 | |
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352 | if (atomic_dec_and_test(fclone_ref)) |
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353 | kmem_cache_free(skbuff_fclone_cache, other); |
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354 | break; |
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355 | }; |
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356 | } |
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357 | |
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358 | /** |
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359 | * __kfree_skb - private function |
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360 | * @skb: buffer |
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361 | * |
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362 | * Free an sk_buff. Release anything attached to the buffer. |
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363 | * Clean the state. This is an internal helper function. Users should |
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364 | * always call kfree_skb |
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365 | */ |
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366 | |
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367 | void __kfree_skb(struct sk_buff *skb) |
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368 | { |
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369 | dst_release(skb->dst); |
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370 | #ifdef CONFIG_XFRM |
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371 | secpath_put(skb->sp); |
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372 | #endif |
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373 | if (skb->destructor) { |
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374 | WARN_ON(in_irq()); |
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375 | skb->destructor(skb); |
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376 | } |
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377 | #ifdef CONFIG_NETFILTER |
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378 | nf_conntrack_put(skb->nfct); |
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379 | #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) |
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380 | nf_conntrack_put_reasm(skb->nfct_reasm); |
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381 | #endif |
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382 | #ifdef CONFIG_BRIDGE_NETFILTER |
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383 | nf_bridge_put(skb->nf_bridge); |
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384 | #endif |
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385 | #endif |
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386 | /* XXX: IS this still necessary? - JHS */ |
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387 | #ifdef CONFIG_NET_SCHED |
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388 | skb->tc_index = 0; |
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389 | #ifdef CONFIG_NET_CLS_ACT |
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390 | skb->tc_verd = 0; |
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391 | #endif |
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392 | #endif |
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393 | |
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394 | kfree_skbmem(skb); |
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395 | } |
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396 | |
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397 | /** |
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398 | * kfree_skb - free an sk_buff |
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399 | * @skb: buffer to free |
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400 | * |
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401 | * Drop a reference to the buffer and free it if the usage count has |
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402 | * hit zero. |
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403 | */ |
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404 | void kfree_skb(struct sk_buff *skb) |
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405 | { |
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406 | if (unlikely(!skb)) |
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407 | return; |
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408 | if (likely(atomic_read(&skb->users) == 1)) |
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409 | smp_rmb(); |
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410 | else if (likely(!atomic_dec_and_test(&skb->users))) |
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411 | return; |
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412 | __kfree_skb(skb); |
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413 | } |
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414 | |
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415 | /** |
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416 | * skb_clone - duplicate an sk_buff |
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417 | * @skb: buffer to clone |
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418 | * @gfp_mask: allocation priority |
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419 | * |
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420 | * Duplicate an &sk_buff. The new one is not owned by a socket. Both |
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421 | * copies share the same packet data but not structure. The new |
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422 | * buffer has a reference count of 1. If the allocation fails the |
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423 | * function returns %NULL otherwise the new buffer is returned. |
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424 | * |
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425 | * If this function is called from an interrupt gfp_mask() must be |
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426 | * %GFP_ATOMIC. |
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427 | */ |
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428 | |
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429 | struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t gfp_mask) |
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430 | { |
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431 | struct sk_buff *n; |
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432 | |
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433 | n = skb + 1; |
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434 | if (skb->fclone == SKB_FCLONE_ORIG && |
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435 | n->fclone == SKB_FCLONE_UNAVAILABLE) { |
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436 | atomic_t *fclone_ref = (atomic_t *) (n + 1); |
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437 | n->fclone = SKB_FCLONE_CLONE; |
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438 | atomic_inc(fclone_ref); |
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439 | } else { |
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440 | n = kmem_cache_alloc(skbuff_head_cache, gfp_mask); |
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441 | if (!n) |
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442 | return NULL; |
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443 | n->fclone = SKB_FCLONE_UNAVAILABLE; |
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444 | } |
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445 | |
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446 | #define C(x) n->x = skb->x |
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447 | |
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448 | n->next = n->prev = NULL; |
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449 | n->sk = NULL; |
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450 | C(tstamp); |
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451 | C(dev); |
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452 | C(h); |
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453 | C(nh); |
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454 | C(mac); |
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455 | C(dst); |
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456 | dst_clone(skb->dst); |
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457 | C(sp); |
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458 | #ifdef CONFIG_INET |
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459 | secpath_get(skb->sp); |
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460 | #endif |
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461 | memcpy(n->cb, skb->cb, sizeof(skb->cb)); |
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462 | C(len); |
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463 | C(data_len); |
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464 | C(csum); |
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465 | C(local_df); |
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466 | n->cloned = 1; |
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467 | n->nohdr = 0; |
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468 | #ifdef CONFIG_XEN |
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469 | C(proto_data_valid); |
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470 | C(proto_csum_blank); |
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471 | #endif |
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472 | C(pkt_type); |
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473 | C(ip_summed); |
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474 | C(priority); |
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475 | #if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE) |
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476 | C(ipvs_property); |
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477 | #endif |
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478 | C(protocol); |
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479 | n->destructor = NULL; |
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480 | #ifdef CONFIG_NETFILTER |
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481 | C(nfmark); |
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482 | C(nfct); |
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483 | nf_conntrack_get(skb->nfct); |
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484 | C(nfctinfo); |
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485 | #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) |
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486 | C(nfct_reasm); |
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487 | nf_conntrack_get_reasm(skb->nfct_reasm); |
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488 | #endif |
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489 | #ifdef CONFIG_BRIDGE_NETFILTER |
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490 | C(nf_bridge); |
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491 | nf_bridge_get(skb->nf_bridge); |
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492 | #endif |
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493 | #endif /*CONFIG_NETFILTER*/ |
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494 | #ifdef CONFIG_NET_SCHED |
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495 | C(tc_index); |
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496 | #ifdef CONFIG_NET_CLS_ACT |
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497 | n->tc_verd = SET_TC_VERD(skb->tc_verd,0); |
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498 | n->tc_verd = CLR_TC_OK2MUNGE(n->tc_verd); |
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499 | n->tc_verd = CLR_TC_MUNGED(n->tc_verd); |
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500 | C(input_dev); |
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501 | #endif |
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502 | skb_copy_secmark(n, skb); |
---|
503 | #endif |
---|
504 | C(truesize); |
---|
505 | atomic_set(&n->users, 1); |
---|
506 | C(head); |
---|
507 | C(data); |
---|
508 | C(tail); |
---|
509 | C(end); |
---|
510 | |
---|
511 | atomic_inc(&(skb_shinfo(skb)->dataref)); |
---|
512 | skb->cloned = 1; |
---|
513 | |
---|
514 | return n; |
---|
515 | } |
---|
516 | |
---|
517 | static void copy_skb_header(struct sk_buff *new, const struct sk_buff *old) |
---|
518 | { |
---|
519 | /* |
---|
520 | * Shift between the two data areas in bytes |
---|
521 | */ |
---|
522 | unsigned long offset = new->data - old->data; |
---|
523 | |
---|
524 | new->sk = NULL; |
---|
525 | new->dev = old->dev; |
---|
526 | new->priority = old->priority; |
---|
527 | new->protocol = old->protocol; |
---|
528 | new->dst = dst_clone(old->dst); |
---|
529 | #ifdef CONFIG_INET |
---|
530 | new->sp = secpath_get(old->sp); |
---|
531 | #endif |
---|
532 | new->h.raw = old->h.raw + offset; |
---|
533 | new->nh.raw = old->nh.raw + offset; |
---|
534 | new->mac.raw = old->mac.raw + offset; |
---|
535 | memcpy(new->cb, old->cb, sizeof(old->cb)); |
---|
536 | new->local_df = old->local_df; |
---|
537 | new->fclone = SKB_FCLONE_UNAVAILABLE; |
---|
538 | new->pkt_type = old->pkt_type; |
---|
539 | new->tstamp = old->tstamp; |
---|
540 | new->destructor = NULL; |
---|
541 | #ifdef CONFIG_NETFILTER |
---|
542 | new->nfmark = old->nfmark; |
---|
543 | new->nfct = old->nfct; |
---|
544 | nf_conntrack_get(old->nfct); |
---|
545 | new->nfctinfo = old->nfctinfo; |
---|
546 | #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) |
---|
547 | new->nfct_reasm = old->nfct_reasm; |
---|
548 | nf_conntrack_get_reasm(old->nfct_reasm); |
---|
549 | #endif |
---|
550 | #if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE) |
---|
551 | new->ipvs_property = old->ipvs_property; |
---|
552 | #endif |
---|
553 | #ifdef CONFIG_BRIDGE_NETFILTER |
---|
554 | new->nf_bridge = old->nf_bridge; |
---|
555 | nf_bridge_get(old->nf_bridge); |
---|
556 | #endif |
---|
557 | #endif |
---|
558 | #ifdef CONFIG_NET_SCHED |
---|
559 | #ifdef CONFIG_NET_CLS_ACT |
---|
560 | new->tc_verd = old->tc_verd; |
---|
561 | #endif |
---|
562 | new->tc_index = old->tc_index; |
---|
563 | #endif |
---|
564 | skb_copy_secmark(new, old); |
---|
565 | atomic_set(&new->users, 1); |
---|
566 | skb_shinfo(new)->gso_size = skb_shinfo(old)->gso_size; |
---|
567 | skb_shinfo(new)->gso_segs = skb_shinfo(old)->gso_segs; |
---|
568 | skb_shinfo(new)->gso_type = skb_shinfo(old)->gso_type; |
---|
569 | } |
---|
570 | |
---|
571 | /** |
---|
572 | * skb_copy - create private copy of an sk_buff |
---|
573 | * @skb: buffer to copy |
---|
574 | * @gfp_mask: allocation priority |
---|
575 | * |
---|
576 | * Make a copy of both an &sk_buff and its data. This is used when the |
---|
577 | * caller wishes to modify the data and needs a private copy of the |
---|
578 | * data to alter. Returns %NULL on failure or the pointer to the buffer |
---|
579 | * on success. The returned buffer has a reference count of 1. |
---|
580 | * |
---|
581 | * As by-product this function converts non-linear &sk_buff to linear |
---|
582 | * one, so that &sk_buff becomes completely private and caller is allowed |
---|
583 | * to modify all the data of returned buffer. This means that this |
---|
584 | * function is not recommended for use in circumstances when only |
---|
585 | * header is going to be modified. Use pskb_copy() instead. |
---|
586 | */ |
---|
587 | |
---|
588 | struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t gfp_mask) |
---|
589 | { |
---|
590 | int headerlen = skb->data - skb->head; |
---|
591 | /* |
---|
592 | * Allocate the copy buffer |
---|
593 | */ |
---|
594 | struct sk_buff *n = alloc_skb(skb->end - skb->head + skb->data_len, |
---|
595 | gfp_mask); |
---|
596 | if (!n) |
---|
597 | return NULL; |
---|
598 | |
---|
599 | /* Set the data pointer */ |
---|
600 | skb_reserve(n, headerlen); |
---|
601 | /* Set the tail pointer and length */ |
---|
602 | skb_put(n, skb->len); |
---|
603 | n->csum = skb->csum; |
---|
604 | n->ip_summed = skb->ip_summed; |
---|
605 | |
---|
606 | if (skb_copy_bits(skb, -headerlen, n->head, headerlen + skb->len)) |
---|
607 | BUG(); |
---|
608 | |
---|
609 | copy_skb_header(n, skb); |
---|
610 | return n; |
---|
611 | } |
---|
612 | |
---|
613 | |
---|
614 | /** |
---|
615 | * pskb_copy - create copy of an sk_buff with private head. |
---|
616 | * @skb: buffer to copy |
---|
617 | * @gfp_mask: allocation priority |
---|
618 | * |
---|
619 | * Make a copy of both an &sk_buff and part of its data, located |
---|
620 | * in header. Fragmented data remain shared. This is used when |
---|
621 | * the caller wishes to modify only header of &sk_buff and needs |
---|
622 | * private copy of the header to alter. Returns %NULL on failure |
---|
623 | * or the pointer to the buffer on success. |
---|
624 | * The returned buffer has a reference count of 1. |
---|
625 | */ |
---|
626 | |
---|
627 | struct sk_buff *pskb_copy(struct sk_buff *skb, gfp_t gfp_mask) |
---|
628 | { |
---|
629 | /* |
---|
630 | * Allocate the copy buffer |
---|
631 | */ |
---|
632 | struct sk_buff *n = alloc_skb(skb->end - skb->head, gfp_mask); |
---|
633 | |
---|
634 | if (!n) |
---|
635 | goto out; |
---|
636 | |
---|
637 | /* Set the data pointer */ |
---|
638 | skb_reserve(n, skb->data - skb->head); |
---|
639 | /* Set the tail pointer and length */ |
---|
640 | skb_put(n, skb_headlen(skb)); |
---|
641 | /* Copy the bytes */ |
---|
642 | memcpy(n->data, skb->data, n->len); |
---|
643 | n->csum = skb->csum; |
---|
644 | n->ip_summed = skb->ip_summed; |
---|
645 | |
---|
646 | n->data_len = skb->data_len; |
---|
647 | n->len = skb->len; |
---|
648 | |
---|
649 | if (skb_shinfo(skb)->nr_frags) { |
---|
650 | int i; |
---|
651 | |
---|
652 | for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { |
---|
653 | skb_shinfo(n)->frags[i] = skb_shinfo(skb)->frags[i]; |
---|
654 | get_page(skb_shinfo(n)->frags[i].page); |
---|
655 | } |
---|
656 | skb_shinfo(n)->nr_frags = i; |
---|
657 | } |
---|
658 | |
---|
659 | if (skb_shinfo(skb)->frag_list) { |
---|
660 | skb_shinfo(n)->frag_list = skb_shinfo(skb)->frag_list; |
---|
661 | skb_clone_fraglist(n); |
---|
662 | } |
---|
663 | |
---|
664 | copy_skb_header(n, skb); |
---|
665 | out: |
---|
666 | return n; |
---|
667 | } |
---|
668 | |
---|
669 | /** |
---|
670 | * pskb_expand_head - reallocate header of &sk_buff |
---|
671 | * @skb: buffer to reallocate |
---|
672 | * @nhead: room to add at head |
---|
673 | * @ntail: room to add at tail |
---|
674 | * @gfp_mask: allocation priority |
---|
675 | * |
---|
676 | * Expands (or creates identical copy, if &nhead and &ntail are zero) |
---|
677 | * header of skb. &sk_buff itself is not changed. &sk_buff MUST have |
---|
678 | * reference count of 1. Returns zero in the case of success or error, |
---|
679 | * if expansion failed. In the last case, &sk_buff is not changed. |
---|
680 | * |
---|
681 | * All the pointers pointing into skb header may change and must be |
---|
682 | * reloaded after call to this function. |
---|
683 | */ |
---|
684 | |
---|
685 | int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, |
---|
686 | gfp_t gfp_mask) |
---|
687 | { |
---|
688 | int i; |
---|
689 | u8 *data; |
---|
690 | int size = nhead + (skb->end - skb->head) + ntail; |
---|
691 | long off; |
---|
692 | |
---|
693 | if (skb_shared(skb)) |
---|
694 | BUG(); |
---|
695 | |
---|
696 | size = SKB_DATA_ALIGN(size); |
---|
697 | |
---|
698 | data = kmalloc(size + sizeof(struct skb_shared_info), gfp_mask); |
---|
699 | if (!data) |
---|
700 | goto nodata; |
---|
701 | |
---|
702 | /* Copy only real data... and, alas, header. This should be |
---|
703 | * optimized for the cases when header is void. */ |
---|
704 | memcpy(data + nhead, skb->head, skb->tail - skb->head); |
---|
705 | memcpy(data + size, skb->end, sizeof(struct skb_shared_info)); |
---|
706 | |
---|
707 | for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) |
---|
708 | get_page(skb_shinfo(skb)->frags[i].page); |
---|
709 | |
---|
710 | if (skb_shinfo(skb)->frag_list) |
---|
711 | skb_clone_fraglist(skb); |
---|
712 | |
---|
713 | skb_release_data(skb); |
---|
714 | |
---|
715 | off = (data + nhead) - skb->head; |
---|
716 | |
---|
717 | skb->head = data; |
---|
718 | skb->end = data + size; |
---|
719 | skb->data += off; |
---|
720 | skb->tail += off; |
---|
721 | skb->mac.raw += off; |
---|
722 | skb->h.raw += off; |
---|
723 | skb->nh.raw += off; |
---|
724 | skb->cloned = 0; |
---|
725 | skb->nohdr = 0; |
---|
726 | atomic_set(&skb_shinfo(skb)->dataref, 1); |
---|
727 | return 0; |
---|
728 | |
---|
729 | nodata: |
---|
730 | return -ENOMEM; |
---|
731 | } |
---|
732 | |
---|
733 | /* Make private copy of skb with writable head and some headroom */ |
---|
734 | |
---|
735 | struct sk_buff *skb_realloc_headroom(struct sk_buff *skb, unsigned int headroom) |
---|
736 | { |
---|
737 | struct sk_buff *skb2; |
---|
738 | int delta = headroom - skb_headroom(skb); |
---|
739 | |
---|
740 | if (delta <= 0) |
---|
741 | skb2 = pskb_copy(skb, GFP_ATOMIC); |
---|
742 | else { |
---|
743 | skb2 = skb_clone(skb, GFP_ATOMIC); |
---|
744 | if (skb2 && pskb_expand_head(skb2, SKB_DATA_ALIGN(delta), 0, |
---|
745 | GFP_ATOMIC)) { |
---|
746 | kfree_skb(skb2); |
---|
747 | skb2 = NULL; |
---|
748 | } |
---|
749 | } |
---|
750 | return skb2; |
---|
751 | } |
---|
752 | |
---|
753 | |
---|
754 | /** |
---|
755 | * skb_copy_expand - copy and expand sk_buff |
---|
756 | * @skb: buffer to copy |
---|
757 | * @newheadroom: new free bytes at head |
---|
758 | * @newtailroom: new free bytes at tail |
---|
759 | * @gfp_mask: allocation priority |
---|
760 | * |
---|
761 | * Make a copy of both an &sk_buff and its data and while doing so |
---|
762 | * allocate additional space. |
---|
763 | * |
---|
764 | * This is used when the caller wishes to modify the data and needs a |
---|
765 | * private copy of the data to alter as well as more space for new fields. |
---|
766 | * Returns %NULL on failure or the pointer to the buffer |
---|
767 | * on success. The returned buffer has a reference count of 1. |
---|
768 | * |
---|
769 | * You must pass %GFP_ATOMIC as the allocation priority if this function |
---|
770 | * is called from an interrupt. |
---|
771 | * |
---|
772 | * BUG ALERT: ip_summed is not copied. Why does this work? Is it used |
---|
773 | * only by netfilter in the cases when checksum is recalculated? --ANK |
---|
774 | */ |
---|
775 | struct sk_buff *skb_copy_expand(const struct sk_buff *skb, |
---|
776 | int newheadroom, int newtailroom, |
---|
777 | gfp_t gfp_mask) |
---|
778 | { |
---|
779 | /* |
---|
780 | * Allocate the copy buffer |
---|
781 | */ |
---|
782 | struct sk_buff *n = alloc_skb(newheadroom + skb->len + newtailroom, |
---|
783 | gfp_mask); |
---|
784 | int head_copy_len, head_copy_off; |
---|
785 | |
---|
786 | if (!n) |
---|
787 | return NULL; |
---|
788 | |
---|
789 | skb_reserve(n, newheadroom); |
---|
790 | |
---|
791 | /* Set the tail pointer and length */ |
---|
792 | skb_put(n, skb->len); |
---|
793 | |
---|
794 | head_copy_len = skb_headroom(skb); |
---|
795 | head_copy_off = 0; |
---|
796 | if (newheadroom <= head_copy_len) |
---|
797 | head_copy_len = newheadroom; |
---|
798 | else |
---|
799 | head_copy_off = newheadroom - head_copy_len; |
---|
800 | |
---|
801 | /* Copy the linear header and data. */ |
---|
802 | if (skb_copy_bits(skb, -head_copy_len, n->head + head_copy_off, |
---|
803 | skb->len + head_copy_len)) |
---|
804 | BUG(); |
---|
805 | |
---|
806 | copy_skb_header(n, skb); |
---|
807 | |
---|
808 | return n; |
---|
809 | } |
---|
810 | |
---|
811 | /** |
---|
812 | * skb_pad - zero pad the tail of an skb |
---|
813 | * @skb: buffer to pad |
---|
814 | * @pad: space to pad |
---|
815 | * |
---|
816 | * Ensure that a buffer is followed by a padding area that is zero |
---|
817 | * filled. Used by network drivers which may DMA or transfer data |
---|
818 | * beyond the buffer end onto the wire. |
---|
819 | * |
---|
820 | * May return error in out of memory cases. The skb is freed on error. |
---|
821 | */ |
---|
822 | |
---|
823 | int skb_pad(struct sk_buff *skb, int pad) |
---|
824 | { |
---|
825 | int err; |
---|
826 | int ntail; |
---|
827 | |
---|
828 | /* If the skbuff is non linear tailroom is always zero.. */ |
---|
829 | if (!skb_cloned(skb) && skb_tailroom(skb) >= pad) { |
---|
830 | memset(skb->data+skb->len, 0, pad); |
---|
831 | return 0; |
---|
832 | } |
---|
833 | |
---|
834 | ntail = skb->data_len + pad - (skb->end - skb->tail); |
---|
835 | if (likely(skb_cloned(skb) || ntail > 0)) { |
---|
836 | err = pskb_expand_head(skb, 0, ntail, GFP_ATOMIC); |
---|
837 | if (unlikely(err)) |
---|
838 | goto free_skb; |
---|
839 | } |
---|
840 | |
---|
841 | /* FIXME: The use of this function with non-linear skb's really needs |
---|
842 | * to be audited. |
---|
843 | */ |
---|
844 | err = skb_linearize(skb); |
---|
845 | if (unlikely(err)) |
---|
846 | goto free_skb; |
---|
847 | |
---|
848 | memset(skb->data + skb->len, 0, pad); |
---|
849 | return 0; |
---|
850 | |
---|
851 | free_skb: |
---|
852 | kfree_skb(skb); |
---|
853 | return err; |
---|
854 | } |
---|
855 | |
---|
856 | /* Trims skb to length len. It can change skb pointers. |
---|
857 | */ |
---|
858 | |
---|
859 | int ___pskb_trim(struct sk_buff *skb, unsigned int len) |
---|
860 | { |
---|
861 | struct sk_buff **fragp; |
---|
862 | struct sk_buff *frag; |
---|
863 | int offset = skb_headlen(skb); |
---|
864 | int nfrags = skb_shinfo(skb)->nr_frags; |
---|
865 | int i; |
---|
866 | int err; |
---|
867 | |
---|
868 | if (skb_cloned(skb) && |
---|
869 | unlikely((err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))) |
---|
870 | return err; |
---|
871 | |
---|
872 | i = 0; |
---|
873 | if (offset >= len) |
---|
874 | goto drop_pages; |
---|
875 | |
---|
876 | for (; i < nfrags; i++) { |
---|
877 | int end = offset + skb_shinfo(skb)->frags[i].size; |
---|
878 | |
---|
879 | if (end < len) { |
---|
880 | offset = end; |
---|
881 | continue; |
---|
882 | } |
---|
883 | |
---|
884 | skb_shinfo(skb)->frags[i++].size = len - offset; |
---|
885 | |
---|
886 | drop_pages: |
---|
887 | skb_shinfo(skb)->nr_frags = i; |
---|
888 | |
---|
889 | for (; i < nfrags; i++) |
---|
890 | put_page(skb_shinfo(skb)->frags[i].page); |
---|
891 | |
---|
892 | if (skb_shinfo(skb)->frag_list) |
---|
893 | skb_drop_fraglist(skb); |
---|
894 | goto done; |
---|
895 | } |
---|
896 | |
---|
897 | for (fragp = &skb_shinfo(skb)->frag_list; (frag = *fragp); |
---|
898 | fragp = &frag->next) { |
---|
899 | int end = offset + frag->len; |
---|
900 | |
---|
901 | if (skb_shared(frag)) { |
---|
902 | struct sk_buff *nfrag; |
---|
903 | |
---|
904 | nfrag = skb_clone(frag, GFP_ATOMIC); |
---|
905 | if (unlikely(!nfrag)) |
---|
906 | return -ENOMEM; |
---|
907 | |
---|
908 | nfrag->next = frag->next; |
---|
909 | kfree_skb(frag); |
---|
910 | frag = nfrag; |
---|
911 | *fragp = frag; |
---|
912 | } |
---|
913 | |
---|
914 | if (end < len) { |
---|
915 | offset = end; |
---|
916 | continue; |
---|
917 | } |
---|
918 | |
---|
919 | if (end > len && |
---|
920 | unlikely((err = pskb_trim(frag, len - offset)))) |
---|
921 | return err; |
---|
922 | |
---|
923 | if (frag->next) |
---|
924 | skb_drop_list(&frag->next); |
---|
925 | break; |
---|
926 | } |
---|
927 | |
---|
928 | done: |
---|
929 | if (len > skb_headlen(skb)) { |
---|
930 | skb->data_len -= skb->len - len; |
---|
931 | skb->len = len; |
---|
932 | } else { |
---|
933 | skb->len = len; |
---|
934 | skb->data_len = 0; |
---|
935 | skb->tail = skb->data + len; |
---|
936 | } |
---|
937 | |
---|
938 | return 0; |
---|
939 | } |
---|
940 | |
---|
941 | /** |
---|
942 | * __pskb_pull_tail - advance tail of skb header |
---|
943 | * @skb: buffer to reallocate |
---|
944 | * @delta: number of bytes to advance tail |
---|
945 | * |
---|
946 | * The function makes a sense only on a fragmented &sk_buff, |
---|
947 | * it expands header moving its tail forward and copying necessary |
---|
948 | * data from fragmented part. |
---|
949 | * |
---|
950 | * &sk_buff MUST have reference count of 1. |
---|
951 | * |
---|
952 | * Returns %NULL (and &sk_buff does not change) if pull failed |
---|
953 | * or value of new tail of skb in the case of success. |
---|
954 | * |
---|
955 | * All the pointers pointing into skb header may change and must be |
---|
956 | * reloaded after call to this function. |
---|
957 | */ |
---|
958 | |
---|
959 | /* Moves tail of skb head forward, copying data from fragmented part, |
---|
960 | * when it is necessary. |
---|
961 | * 1. It may fail due to malloc failure. |
---|
962 | * 2. It may change skb pointers. |
---|
963 | * |
---|
964 | * It is pretty complicated. Luckily, it is called only in exceptional cases. |
---|
965 | */ |
---|
966 | unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta) |
---|
967 | { |
---|
968 | /* If skb has not enough free space at tail, get new one |
---|
969 | * plus 128 bytes for future expansions. If we have enough |
---|
970 | * room at tail, reallocate without expansion only if skb is cloned. |
---|
971 | */ |
---|
972 | int i, k, eat = (skb->tail + delta) - skb->end; |
---|
973 | |
---|
974 | if (eat > 0 || skb_cloned(skb)) { |
---|
975 | if (pskb_expand_head(skb, 0, eat > 0 ? eat + 128 : 0, |
---|
976 | GFP_ATOMIC)) |
---|
977 | return NULL; |
---|
978 | } |
---|
979 | |
---|
980 | if (skb_copy_bits(skb, skb_headlen(skb), skb->tail, delta)) |
---|
981 | BUG(); |
---|
982 | |
---|
983 | /* Optimization: no fragments, no reasons to preestimate |
---|
984 | * size of pulled pages. Superb. |
---|
985 | */ |
---|
986 | if (!skb_shinfo(skb)->frag_list) |
---|
987 | goto pull_pages; |
---|
988 | |
---|
989 | /* Estimate size of pulled pages. */ |
---|
990 | eat = delta; |
---|
991 | for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { |
---|
992 | if (skb_shinfo(skb)->frags[i].size >= eat) |
---|
993 | goto pull_pages; |
---|
994 | eat -= skb_shinfo(skb)->frags[i].size; |
---|
995 | } |
---|
996 | |
---|
997 | /* If we need update frag list, we are in troubles. |
---|
998 | * Certainly, it possible to add an offset to skb data, |
---|
999 | * but taking into account that pulling is expected to |
---|
1000 | * be very rare operation, it is worth to fight against |
---|
1001 | * further bloating skb head and crucify ourselves here instead. |
---|
1002 | * Pure masohism, indeed. 8)8) |
---|
1003 | */ |
---|
1004 | if (eat) { |
---|
1005 | struct sk_buff *list = skb_shinfo(skb)->frag_list; |
---|
1006 | struct sk_buff *clone = NULL; |
---|
1007 | struct sk_buff *insp = NULL; |
---|
1008 | |
---|
1009 | do { |
---|
1010 | BUG_ON(!list); |
---|
1011 | |
---|
1012 | if (list->len <= eat) { |
---|
1013 | /* Eaten as whole. */ |
---|
1014 | eat -= list->len; |
---|
1015 | list = list->next; |
---|
1016 | insp = list; |
---|
1017 | } else { |
---|
1018 | /* Eaten partially. */ |
---|
1019 | |
---|
1020 | if (skb_shared(list)) { |
---|
1021 | /* Sucks! We need to fork list. :-( */ |
---|
1022 | clone = skb_clone(list, GFP_ATOMIC); |
---|
1023 | if (!clone) |
---|
1024 | return NULL; |
---|
1025 | insp = list->next; |
---|
1026 | list = clone; |
---|
1027 | } else { |
---|
1028 | /* This may be pulled without |
---|
1029 | * problems. */ |
---|
1030 | insp = list; |
---|
1031 | } |
---|
1032 | if (!pskb_pull(list, eat)) { |
---|
1033 | if (clone) |
---|
1034 | kfree_skb(clone); |
---|
1035 | return NULL; |
---|
1036 | } |
---|
1037 | break; |
---|
1038 | } |
---|
1039 | } while (eat); |
---|
1040 | |
---|
1041 | /* Free pulled out fragments. */ |
---|
1042 | while ((list = skb_shinfo(skb)->frag_list) != insp) { |
---|
1043 | skb_shinfo(skb)->frag_list = list->next; |
---|
1044 | kfree_skb(list); |
---|
1045 | } |
---|
1046 | /* And insert new clone at head. */ |
---|
1047 | if (clone) { |
---|
1048 | clone->next = list; |
---|
1049 | skb_shinfo(skb)->frag_list = clone; |
---|
1050 | } |
---|
1051 | } |
---|
1052 | /* Success! Now we may commit changes to skb data. */ |
---|
1053 | |
---|
1054 | pull_pages: |
---|
1055 | eat = delta; |
---|
1056 | k = 0; |
---|
1057 | for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { |
---|
1058 | if (skb_shinfo(skb)->frags[i].size <= eat) { |
---|
1059 | put_page(skb_shinfo(skb)->frags[i].page); |
---|
1060 | eat -= skb_shinfo(skb)->frags[i].size; |
---|
1061 | } else { |
---|
1062 | skb_shinfo(skb)->frags[k] = skb_shinfo(skb)->frags[i]; |
---|
1063 | if (eat) { |
---|
1064 | skb_shinfo(skb)->frags[k].page_offset += eat; |
---|
1065 | skb_shinfo(skb)->frags[k].size -= eat; |
---|
1066 | eat = 0; |
---|
1067 | } |
---|
1068 | k++; |
---|
1069 | } |
---|
1070 | } |
---|
1071 | skb_shinfo(skb)->nr_frags = k; |
---|
1072 | |
---|
1073 | skb->tail += delta; |
---|
1074 | skb->data_len -= delta; |
---|
1075 | |
---|
1076 | return skb->tail; |
---|
1077 | } |
---|
1078 | |
---|
1079 | /* Copy some data bits from skb to kernel buffer. */ |
---|
1080 | |
---|
1081 | int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len) |
---|
1082 | { |
---|
1083 | int i, copy; |
---|
1084 | int start = skb_headlen(skb); |
---|
1085 | |
---|
1086 | if (offset > (int)skb->len - len) |
---|
1087 | goto fault; |
---|
1088 | |
---|
1089 | /* Copy header. */ |
---|
1090 | if ((copy = start - offset) > 0) { |
---|
1091 | if (copy > len) |
---|
1092 | copy = len; |
---|
1093 | memcpy(to, skb->data + offset, copy); |
---|
1094 | if ((len -= copy) == 0) |
---|
1095 | return 0; |
---|
1096 | offset += copy; |
---|
1097 | to += copy; |
---|
1098 | } |
---|
1099 | |
---|
1100 | for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { |
---|
1101 | int end; |
---|
1102 | |
---|
1103 | BUG_TRAP(start <= offset + len); |
---|
1104 | |
---|
1105 | end = start + skb_shinfo(skb)->frags[i].size; |
---|
1106 | if ((copy = end - offset) > 0) { |
---|
1107 | u8 *vaddr; |
---|
1108 | |
---|
1109 | if (copy > len) |
---|
1110 | copy = len; |
---|
1111 | |
---|
1112 | vaddr = kmap_skb_frag(&skb_shinfo(skb)->frags[i]); |
---|
1113 | memcpy(to, |
---|
1114 | vaddr + skb_shinfo(skb)->frags[i].page_offset+ |
---|
1115 | offset - start, copy); |
---|
1116 | kunmap_skb_frag(vaddr); |
---|
1117 | |
---|
1118 | if ((len -= copy) == 0) |
---|
1119 | return 0; |
---|
1120 | offset += copy; |
---|
1121 | to += copy; |
---|
1122 | } |
---|
1123 | start = end; |
---|
1124 | } |
---|
1125 | |
---|
1126 | if (skb_shinfo(skb)->frag_list) { |
---|
1127 | struct sk_buff *list = skb_shinfo(skb)->frag_list; |
---|
1128 | |
---|
1129 | for (; list; list = list->next) { |
---|
1130 | int end; |
---|
1131 | |
---|
1132 | BUG_TRAP(start <= offset + len); |
---|
1133 | |
---|
1134 | end = start + list->len; |
---|
1135 | if ((copy = end - offset) > 0) { |
---|
1136 | if (copy > len) |
---|
1137 | copy = len; |
---|
1138 | if (skb_copy_bits(list, offset - start, |
---|
1139 | to, copy)) |
---|
1140 | goto fault; |
---|
1141 | if ((len -= copy) == 0) |
---|
1142 | return 0; |
---|
1143 | offset += copy; |
---|
1144 | to += copy; |
---|
1145 | } |
---|
1146 | start = end; |
---|
1147 | } |
---|
1148 | } |
---|
1149 | if (!len) |
---|
1150 | return 0; |
---|
1151 | |
---|
1152 | fault: |
---|
1153 | return -EFAULT; |
---|
1154 | } |
---|
1155 | |
---|
1156 | /** |
---|
1157 | * skb_store_bits - store bits from kernel buffer to skb |
---|
1158 | * @skb: destination buffer |
---|
1159 | * @offset: offset in destination |
---|
1160 | * @from: source buffer |
---|
1161 | * @len: number of bytes to copy |
---|
1162 | * |
---|
1163 | * Copy the specified number of bytes from the source buffer to the |
---|
1164 | * destination skb. This function handles all the messy bits of |
---|
1165 | * traversing fragment lists and such. |
---|
1166 | */ |
---|
1167 | |
---|
1168 | int skb_store_bits(const struct sk_buff *skb, int offset, void *from, int len) |
---|
1169 | { |
---|
1170 | int i, copy; |
---|
1171 | int start = skb_headlen(skb); |
---|
1172 | |
---|
1173 | if (offset > (int)skb->len - len) |
---|
1174 | goto fault; |
---|
1175 | |
---|
1176 | if ((copy = start - offset) > 0) { |
---|
1177 | if (copy > len) |
---|
1178 | copy = len; |
---|
1179 | memcpy(skb->data + offset, from, copy); |
---|
1180 | if ((len -= copy) == 0) |
---|
1181 | return 0; |
---|
1182 | offset += copy; |
---|
1183 | from += copy; |
---|
1184 | } |
---|
1185 | |
---|
1186 | for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { |
---|
1187 | skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; |
---|
1188 | int end; |
---|
1189 | |
---|
1190 | BUG_TRAP(start <= offset + len); |
---|
1191 | |
---|
1192 | end = start + frag->size; |
---|
1193 | if ((copy = end - offset) > 0) { |
---|
1194 | u8 *vaddr; |
---|
1195 | |
---|
1196 | if (copy > len) |
---|
1197 | copy = len; |
---|
1198 | |
---|
1199 | vaddr = kmap_skb_frag(frag); |
---|
1200 | memcpy(vaddr + frag->page_offset + offset - start, |
---|
1201 | from, copy); |
---|
1202 | kunmap_skb_frag(vaddr); |
---|
1203 | |
---|
1204 | if ((len -= copy) == 0) |
---|
1205 | return 0; |
---|
1206 | offset += copy; |
---|
1207 | from += copy; |
---|
1208 | } |
---|
1209 | start = end; |
---|
1210 | } |
---|
1211 | |
---|
1212 | if (skb_shinfo(skb)->frag_list) { |
---|
1213 | struct sk_buff *list = skb_shinfo(skb)->frag_list; |
---|
1214 | |
---|
1215 | for (; list; list = list->next) { |
---|
1216 | int end; |
---|
1217 | |
---|
1218 | BUG_TRAP(start <= offset + len); |
---|
1219 | |
---|
1220 | end = start + list->len; |
---|
1221 | if ((copy = end - offset) > 0) { |
---|
1222 | if (copy > len) |
---|
1223 | copy = len; |
---|
1224 | if (skb_store_bits(list, offset - start, |
---|
1225 | from, copy)) |
---|
1226 | goto fault; |
---|
1227 | if ((len -= copy) == 0) |
---|
1228 | return 0; |
---|
1229 | offset += copy; |
---|
1230 | from += copy; |
---|
1231 | } |
---|
1232 | start = end; |
---|
1233 | } |
---|
1234 | } |
---|
1235 | if (!len) |
---|
1236 | return 0; |
---|
1237 | |
---|
1238 | fault: |
---|
1239 | return -EFAULT; |
---|
1240 | } |
---|
1241 | |
---|
1242 | EXPORT_SYMBOL(skb_store_bits); |
---|
1243 | |
---|
1244 | /* Checksum skb data. */ |
---|
1245 | |
---|
1246 | unsigned int skb_checksum(const struct sk_buff *skb, int offset, |
---|
1247 | int len, unsigned int csum) |
---|
1248 | { |
---|
1249 | int start = skb_headlen(skb); |
---|
1250 | int i, copy = start - offset; |
---|
1251 | int pos = 0; |
---|
1252 | |
---|
1253 | /* Checksum header. */ |
---|
1254 | if (copy > 0) { |
---|
1255 | if (copy > len) |
---|
1256 | copy = len; |
---|
1257 | csum = csum_partial(skb->data + offset, copy, csum); |
---|
1258 | if ((len -= copy) == 0) |
---|
1259 | return csum; |
---|
1260 | offset += copy; |
---|
1261 | pos = copy; |
---|
1262 | } |
---|
1263 | |
---|
1264 | for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { |
---|
1265 | int end; |
---|
1266 | |
---|
1267 | BUG_TRAP(start <= offset + len); |
---|
1268 | |
---|
1269 | end = start + skb_shinfo(skb)->frags[i].size; |
---|
1270 | if ((copy = end - offset) > 0) { |
---|
1271 | unsigned int csum2; |
---|
1272 | u8 *vaddr; |
---|
1273 | skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; |
---|
1274 | |
---|
1275 | if (copy > len) |
---|
1276 | copy = len; |
---|
1277 | vaddr = kmap_skb_frag(frag); |
---|
1278 | csum2 = csum_partial(vaddr + frag->page_offset + |
---|
1279 | offset - start, copy, 0); |
---|
1280 | kunmap_skb_frag(vaddr); |
---|
1281 | csum = csum_block_add(csum, csum2, pos); |
---|
1282 | if (!(len -= copy)) |
---|
1283 | return csum; |
---|
1284 | offset += copy; |
---|
1285 | pos += copy; |
---|
1286 | } |
---|
1287 | start = end; |
---|
1288 | } |
---|
1289 | |
---|
1290 | if (skb_shinfo(skb)->frag_list) { |
---|
1291 | struct sk_buff *list = skb_shinfo(skb)->frag_list; |
---|
1292 | |
---|
1293 | for (; list; list = list->next) { |
---|
1294 | int end; |
---|
1295 | |
---|
1296 | BUG_TRAP(start <= offset + len); |
---|
1297 | |
---|
1298 | end = start + list->len; |
---|
1299 | if ((copy = end - offset) > 0) { |
---|
1300 | unsigned int csum2; |
---|
1301 | if (copy > len) |
---|
1302 | copy = len; |
---|
1303 | csum2 = skb_checksum(list, offset - start, |
---|
1304 | copy, 0); |
---|
1305 | csum = csum_block_add(csum, csum2, pos); |
---|
1306 | if ((len -= copy) == 0) |
---|
1307 | return csum; |
---|
1308 | offset += copy; |
---|
1309 | pos += copy; |
---|
1310 | } |
---|
1311 | start = end; |
---|
1312 | } |
---|
1313 | } |
---|
1314 | BUG_ON(len); |
---|
1315 | |
---|
1316 | return csum; |
---|
1317 | } |
---|
1318 | |
---|
1319 | /* Both of above in one bottle. */ |
---|
1320 | |
---|
1321 | unsigned int skb_copy_and_csum_bits(const struct sk_buff *skb, int offset, |
---|
1322 | u8 *to, int len, unsigned int csum) |
---|
1323 | { |
---|
1324 | int start = skb_headlen(skb); |
---|
1325 | int i, copy = start - offset; |
---|
1326 | int pos = 0; |
---|
1327 | |
---|
1328 | /* Copy header. */ |
---|
1329 | if (copy > 0) { |
---|
1330 | if (copy > len) |
---|
1331 | copy = len; |
---|
1332 | csum = csum_partial_copy_nocheck(skb->data + offset, to, |
---|
1333 | copy, csum); |
---|
1334 | if ((len -= copy) == 0) |
---|
1335 | return csum; |
---|
1336 | offset += copy; |
---|
1337 | to += copy; |
---|
1338 | pos = copy; |
---|
1339 | } |
---|
1340 | |
---|
1341 | for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { |
---|
1342 | int end; |
---|
1343 | |
---|
1344 | BUG_TRAP(start <= offset + len); |
---|
1345 | |
---|
1346 | end = start + skb_shinfo(skb)->frags[i].size; |
---|
1347 | if ((copy = end - offset) > 0) { |
---|
1348 | unsigned int csum2; |
---|
1349 | u8 *vaddr; |
---|
1350 | skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; |
---|
1351 | |
---|
1352 | if (copy > len) |
---|
1353 | copy = len; |
---|
1354 | vaddr = kmap_skb_frag(frag); |
---|
1355 | csum2 = csum_partial_copy_nocheck(vaddr + |
---|
1356 | frag->page_offset + |
---|
1357 | offset - start, to, |
---|
1358 | copy, 0); |
---|
1359 | kunmap_skb_frag(vaddr); |
---|
1360 | csum = csum_block_add(csum, csum2, pos); |
---|
1361 | if (!(len -= copy)) |
---|
1362 | return csum; |
---|
1363 | offset += copy; |
---|
1364 | to += copy; |
---|
1365 | pos += copy; |
---|
1366 | } |
---|
1367 | start = end; |
---|
1368 | } |
---|
1369 | |
---|
1370 | if (skb_shinfo(skb)->frag_list) { |
---|
1371 | struct sk_buff *list = skb_shinfo(skb)->frag_list; |
---|
1372 | |
---|
1373 | for (; list; list = list->next) { |
---|
1374 | unsigned int csum2; |
---|
1375 | int end; |
---|
1376 | |
---|
1377 | BUG_TRAP(start <= offset + len); |
---|
1378 | |
---|
1379 | end = start + list->len; |
---|
1380 | if ((copy = end - offset) > 0) { |
---|
1381 | if (copy > len) |
---|
1382 | copy = len; |
---|
1383 | csum2 = skb_copy_and_csum_bits(list, |
---|
1384 | offset - start, |
---|
1385 | to, copy, 0); |
---|
1386 | csum = csum_block_add(csum, csum2, pos); |
---|
1387 | if ((len -= copy) == 0) |
---|
1388 | return csum; |
---|
1389 | offset += copy; |
---|
1390 | to += copy; |
---|
1391 | pos += copy; |
---|
1392 | } |
---|
1393 | start = end; |
---|
1394 | } |
---|
1395 | } |
---|
1396 | BUG_ON(len); |
---|
1397 | return csum; |
---|
1398 | } |
---|
1399 | |
---|
1400 | void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to) |
---|
1401 | { |
---|
1402 | unsigned int csum; |
---|
1403 | long csstart; |
---|
1404 | |
---|
1405 | if (skb->ip_summed == CHECKSUM_HW) |
---|
1406 | csstart = skb->h.raw - skb->data; |
---|
1407 | else |
---|
1408 | csstart = skb_headlen(skb); |
---|
1409 | |
---|
1410 | BUG_ON(csstart > skb_headlen(skb)); |
---|
1411 | |
---|
1412 | memcpy(to, skb->data, csstart); |
---|
1413 | |
---|
1414 | csum = 0; |
---|
1415 | if (csstart != skb->len) |
---|
1416 | csum = skb_copy_and_csum_bits(skb, csstart, to + csstart, |
---|
1417 | skb->len - csstart, 0); |
---|
1418 | |
---|
1419 | if (skb->ip_summed == CHECKSUM_HW) { |
---|
1420 | long csstuff = csstart + skb->csum; |
---|
1421 | |
---|
1422 | *((unsigned short *)(to + csstuff)) = csum_fold(csum); |
---|
1423 | } |
---|
1424 | } |
---|
1425 | |
---|
1426 | /** |
---|
1427 | * skb_dequeue - remove from the head of the queue |
---|
1428 | * @list: list to dequeue from |
---|
1429 | * |
---|
1430 | * Remove the head of the list. The list lock is taken so the function |
---|
1431 | * may be used safely with other locking list functions. The head item is |
---|
1432 | * returned or %NULL if the list is empty. |
---|
1433 | */ |
---|
1434 | |
---|
1435 | struct sk_buff *skb_dequeue(struct sk_buff_head *list) |
---|
1436 | { |
---|
1437 | unsigned long flags; |
---|
1438 | struct sk_buff *result; |
---|
1439 | |
---|
1440 | spin_lock_irqsave(&list->lock, flags); |
---|
1441 | result = __skb_dequeue(list); |
---|
1442 | spin_unlock_irqrestore(&list->lock, flags); |
---|
1443 | return result; |
---|
1444 | } |
---|
1445 | |
---|
1446 | /** |
---|
1447 | * skb_dequeue_tail - remove from the tail of the queue |
---|
1448 | * @list: list to dequeue from |
---|
1449 | * |
---|
1450 | * Remove the tail of the list. The list lock is taken so the function |
---|
1451 | * may be used safely with other locking list functions. The tail item is |
---|
1452 | * returned or %NULL if the list is empty. |
---|
1453 | */ |
---|
1454 | struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list) |
---|
1455 | { |
---|
1456 | unsigned long flags; |
---|
1457 | struct sk_buff *result; |
---|
1458 | |
---|
1459 | spin_lock_irqsave(&list->lock, flags); |
---|
1460 | result = __skb_dequeue_tail(list); |
---|
1461 | spin_unlock_irqrestore(&list->lock, flags); |
---|
1462 | return result; |
---|
1463 | } |
---|
1464 | |
---|
1465 | /** |
---|
1466 | * skb_queue_purge - empty a list |
---|
1467 | * @list: list to empty |
---|
1468 | * |
---|
1469 | * Delete all buffers on an &sk_buff list. Each buffer is removed from |
---|
1470 | * the list and one reference dropped. This function takes the list |
---|
1471 | * lock and is atomic with respect to other list locking functions. |
---|
1472 | */ |
---|
1473 | void skb_queue_purge(struct sk_buff_head *list) |
---|
1474 | { |
---|
1475 | struct sk_buff *skb; |
---|
1476 | while ((skb = skb_dequeue(list)) != NULL) |
---|
1477 | kfree_skb(skb); |
---|
1478 | } |
---|
1479 | |
---|
1480 | /** |
---|
1481 | * skb_queue_head - queue a buffer at the list head |
---|
1482 | * @list: list to use |
---|
1483 | * @newsk: buffer to queue |
---|
1484 | * |
---|
1485 | * Queue a buffer at the start of the list. This function takes the |
---|
1486 | * list lock and can be used safely with other locking &sk_buff functions |
---|
1487 | * safely. |
---|
1488 | * |
---|
1489 | * A buffer cannot be placed on two lists at the same time. |
---|
1490 | */ |
---|
1491 | void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk) |
---|
1492 | { |
---|
1493 | unsigned long flags; |
---|
1494 | |
---|
1495 | spin_lock_irqsave(&list->lock, flags); |
---|
1496 | __skb_queue_head(list, newsk); |
---|
1497 | spin_unlock_irqrestore(&list->lock, flags); |
---|
1498 | } |
---|
1499 | |
---|
1500 | /** |
---|
1501 | * skb_queue_tail - queue a buffer at the list tail |
---|
1502 | * @list: list to use |
---|
1503 | * @newsk: buffer to queue |
---|
1504 | * |
---|
1505 | * Queue a buffer at the tail of the list. This function takes the |
---|
1506 | * list lock and can be used safely with other locking &sk_buff functions |
---|
1507 | * safely. |
---|
1508 | * |
---|
1509 | * A buffer cannot be placed on two lists at the same time. |
---|
1510 | */ |
---|
1511 | void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk) |
---|
1512 | { |
---|
1513 | unsigned long flags; |
---|
1514 | |
---|
1515 | spin_lock_irqsave(&list->lock, flags); |
---|
1516 | __skb_queue_tail(list, newsk); |
---|
1517 | spin_unlock_irqrestore(&list->lock, flags); |
---|
1518 | } |
---|
1519 | |
---|
1520 | /** |
---|
1521 | * skb_unlink - remove a buffer from a list |
---|
1522 | * @skb: buffer to remove |
---|
1523 | * @list: list to use |
---|
1524 | * |
---|
1525 | * Remove a packet from a list. The list locks are taken and this |
---|
1526 | * function is atomic with respect to other list locked calls |
---|
1527 | * |
---|
1528 | * You must know what list the SKB is on. |
---|
1529 | */ |
---|
1530 | void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list) |
---|
1531 | { |
---|
1532 | unsigned long flags; |
---|
1533 | |
---|
1534 | spin_lock_irqsave(&list->lock, flags); |
---|
1535 | __skb_unlink(skb, list); |
---|
1536 | spin_unlock_irqrestore(&list->lock, flags); |
---|
1537 | } |
---|
1538 | |
---|
1539 | /** |
---|
1540 | * skb_append - append a buffer |
---|
1541 | * @old: buffer to insert after |
---|
1542 | * @newsk: buffer to insert |
---|
1543 | * @list: list to use |
---|
1544 | * |
---|
1545 | * Place a packet after a given packet in a list. The list locks are taken |
---|
1546 | * and this function is atomic with respect to other list locked calls. |
---|
1547 | * A buffer cannot be placed on two lists at the same time. |
---|
1548 | */ |
---|
1549 | void skb_append(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list) |
---|
1550 | { |
---|
1551 | unsigned long flags; |
---|
1552 | |
---|
1553 | spin_lock_irqsave(&list->lock, flags); |
---|
1554 | __skb_append(old, newsk, list); |
---|
1555 | spin_unlock_irqrestore(&list->lock, flags); |
---|
1556 | } |
---|
1557 | |
---|
1558 | |
---|
1559 | /** |
---|
1560 | * skb_insert - insert a buffer |
---|
1561 | * @old: buffer to insert before |
---|
1562 | * @newsk: buffer to insert |
---|
1563 | * @list: list to use |
---|
1564 | * |
---|
1565 | * Place a packet before a given packet in a list. The list locks are |
---|
1566 | * taken and this function is atomic with respect to other list locked |
---|
1567 | * calls. |
---|
1568 | * |
---|
1569 | * A buffer cannot be placed on two lists at the same time. |
---|
1570 | */ |
---|
1571 | void skb_insert(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list) |
---|
1572 | { |
---|
1573 | unsigned long flags; |
---|
1574 | |
---|
1575 | spin_lock_irqsave(&list->lock, flags); |
---|
1576 | __skb_insert(newsk, old->prev, old, list); |
---|
1577 | spin_unlock_irqrestore(&list->lock, flags); |
---|
1578 | } |
---|
1579 | |
---|
1580 | #if 0 |
---|
1581 | /* |
---|
1582 | * Tune the memory allocator for a new MTU size. |
---|
1583 | */ |
---|
1584 | void skb_add_mtu(int mtu) |
---|
1585 | { |
---|
1586 | /* Must match allocation in alloc_skb */ |
---|
1587 | mtu = SKB_DATA_ALIGN(mtu) + sizeof(struct skb_shared_info); |
---|
1588 | |
---|
1589 | kmem_add_cache_size(mtu); |
---|
1590 | } |
---|
1591 | #endif |
---|
1592 | |
---|
1593 | static inline void skb_split_inside_header(struct sk_buff *skb, |
---|
1594 | struct sk_buff* skb1, |
---|
1595 | const u32 len, const int pos) |
---|
1596 | { |
---|
1597 | int i; |
---|
1598 | |
---|
1599 | memcpy(skb_put(skb1, pos - len), skb->data + len, pos - len); |
---|
1600 | |
---|
1601 | /* And move data appendix as is. */ |
---|
1602 | for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) |
---|
1603 | skb_shinfo(skb1)->frags[i] = skb_shinfo(skb)->frags[i]; |
---|
1604 | |
---|
1605 | skb_shinfo(skb1)->nr_frags = skb_shinfo(skb)->nr_frags; |
---|
1606 | skb_shinfo(skb)->nr_frags = 0; |
---|
1607 | skb1->data_len = skb->data_len; |
---|
1608 | skb1->len += skb1->data_len; |
---|
1609 | skb->data_len = 0; |
---|
1610 | skb->len = len; |
---|
1611 | skb->tail = skb->data + len; |
---|
1612 | } |
---|
1613 | |
---|
1614 | static inline void skb_split_no_header(struct sk_buff *skb, |
---|
1615 | struct sk_buff* skb1, |
---|
1616 | const u32 len, int pos) |
---|
1617 | { |
---|
1618 | int i, k = 0; |
---|
1619 | const int nfrags = skb_shinfo(skb)->nr_frags; |
---|
1620 | |
---|
1621 | skb_shinfo(skb)->nr_frags = 0; |
---|
1622 | skb1->len = skb1->data_len = skb->len - len; |
---|
1623 | skb->len = len; |
---|
1624 | skb->data_len = len - pos; |
---|
1625 | |
---|
1626 | for (i = 0; i < nfrags; i++) { |
---|
1627 | int size = skb_shinfo(skb)->frags[i].size; |
---|
1628 | |
---|
1629 | if (pos + size > len) { |
---|
1630 | skb_shinfo(skb1)->frags[k] = skb_shinfo(skb)->frags[i]; |
---|
1631 | |
---|
1632 | if (pos < len) { |
---|
1633 | /* Split frag. |
---|
1634 | * We have two variants in this case: |
---|
1635 | * 1. Move all the frag to the second |
---|
1636 | * part, if it is possible. F.e. |
---|
1637 | * this approach is mandatory for TUX, |
---|
1638 | * where splitting is expensive. |
---|
1639 | * 2. Split is accurately. We make this. |
---|
1640 | */ |
---|
1641 | get_page(skb_shinfo(skb)->frags[i].page); |
---|
1642 | skb_shinfo(skb1)->frags[0].page_offset += len - pos; |
---|
1643 | skb_shinfo(skb1)->frags[0].size -= len - pos; |
---|
1644 | skb_shinfo(skb)->frags[i].size = len - pos; |
---|
1645 | skb_shinfo(skb)->nr_frags++; |
---|
1646 | } |
---|
1647 | k++; |
---|
1648 | } else |
---|
1649 | skb_shinfo(skb)->nr_frags++; |
---|
1650 | pos += size; |
---|
1651 | } |
---|
1652 | skb_shinfo(skb1)->nr_frags = k; |
---|
1653 | } |
---|
1654 | |
---|
1655 | /** |
---|
1656 | * skb_split - Split fragmented skb to two parts at length len. |
---|
1657 | * @skb: the buffer to split |
---|
1658 | * @skb1: the buffer to receive the second part |
---|
1659 | * @len: new length for skb |
---|
1660 | */ |
---|
1661 | void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len) |
---|
1662 | { |
---|
1663 | int pos = skb_headlen(skb); |
---|
1664 | |
---|
1665 | if (len < pos) /* Split line is inside header. */ |
---|
1666 | skb_split_inside_header(skb, skb1, len, pos); |
---|
1667 | else /* Second chunk has no header, nothing to copy. */ |
---|
1668 | skb_split_no_header(skb, skb1, len, pos); |
---|
1669 | } |
---|
1670 | |
---|
1671 | /** |
---|
1672 | * skb_prepare_seq_read - Prepare a sequential read of skb data |
---|
1673 | * @skb: the buffer to read |
---|
1674 | * @from: lower offset of data to be read |
---|
1675 | * @to: upper offset of data to be read |
---|
1676 | * @st: state variable |
---|
1677 | * |
---|
1678 | * Initializes the specified state variable. Must be called before |
---|
1679 | * invoking skb_seq_read() for the first time. |
---|
1680 | */ |
---|
1681 | void skb_prepare_seq_read(struct sk_buff *skb, unsigned int from, |
---|
1682 | unsigned int to, struct skb_seq_state *st) |
---|
1683 | { |
---|
1684 | st->lower_offset = from; |
---|
1685 | st->upper_offset = to; |
---|
1686 | st->root_skb = st->cur_skb = skb; |
---|
1687 | st->frag_idx = st->stepped_offset = 0; |
---|
1688 | st->frag_data = NULL; |
---|
1689 | } |
---|
1690 | |
---|
1691 | /** |
---|
1692 | * skb_seq_read - Sequentially read skb data |
---|
1693 | * @consumed: number of bytes consumed by the caller so far |
---|
1694 | * @data: destination pointer for data to be returned |
---|
1695 | * @st: state variable |
---|
1696 | * |
---|
1697 | * Reads a block of skb data at &consumed relative to the |
---|
1698 | * lower offset specified to skb_prepare_seq_read(). Assigns |
---|
1699 | * the head of the data block to &data and returns the length |
---|
1700 | * of the block or 0 if the end of the skb data or the upper |
---|
1701 | * offset has been reached. |
---|
1702 | * |
---|
1703 | * The caller is not required to consume all of the data |
---|
1704 | * returned, i.e. &consumed is typically set to the number |
---|
1705 | * of bytes already consumed and the next call to |
---|
1706 | * skb_seq_read() will return the remaining part of the block. |
---|
1707 | * |
---|
1708 | * Note: The size of each block of data returned can be arbitary, |
---|
1709 | * this limitation is the cost for zerocopy seqeuental |
---|
1710 | * reads of potentially non linear data. |
---|
1711 | * |
---|
1712 | * Note: Fragment lists within fragments are not implemented |
---|
1713 | * at the moment, state->root_skb could be replaced with |
---|
1714 | * a stack for this purpose. |
---|
1715 | */ |
---|
1716 | unsigned int skb_seq_read(unsigned int consumed, const u8 **data, |
---|
1717 | struct skb_seq_state *st) |
---|
1718 | { |
---|
1719 | unsigned int block_limit, abs_offset = consumed + st->lower_offset; |
---|
1720 | skb_frag_t *frag; |
---|
1721 | |
---|
1722 | if (unlikely(abs_offset >= st->upper_offset)) |
---|
1723 | return 0; |
---|
1724 | |
---|
1725 | next_skb: |
---|
1726 | block_limit = skb_headlen(st->cur_skb); |
---|
1727 | |
---|
1728 | if (abs_offset < block_limit) { |
---|
1729 | *data = st->cur_skb->data + abs_offset; |
---|
1730 | return block_limit - abs_offset; |
---|
1731 | } |
---|
1732 | |
---|
1733 | if (st->frag_idx == 0 && !st->frag_data) |
---|
1734 | st->stepped_offset += skb_headlen(st->cur_skb); |
---|
1735 | |
---|
1736 | while (st->frag_idx < skb_shinfo(st->cur_skb)->nr_frags) { |
---|
1737 | frag = &skb_shinfo(st->cur_skb)->frags[st->frag_idx]; |
---|
1738 | block_limit = frag->size + st->stepped_offset; |
---|
1739 | |
---|
1740 | if (abs_offset < block_limit) { |
---|
1741 | if (!st->frag_data) |
---|
1742 | st->frag_data = kmap_skb_frag(frag); |
---|
1743 | |
---|
1744 | *data = (u8 *) st->frag_data + frag->page_offset + |
---|
1745 | (abs_offset - st->stepped_offset); |
---|
1746 | |
---|
1747 | return block_limit - abs_offset; |
---|
1748 | } |
---|
1749 | |
---|
1750 | if (st->frag_data) { |
---|
1751 | kunmap_skb_frag(st->frag_data); |
---|
1752 | st->frag_data = NULL; |
---|
1753 | } |
---|
1754 | |
---|
1755 | st->frag_idx++; |
---|
1756 | st->stepped_offset += frag->size; |
---|
1757 | } |
---|
1758 | |
---|
1759 | if (st->cur_skb->next) { |
---|
1760 | st->cur_skb = st->cur_skb->next; |
---|
1761 | st->frag_idx = 0; |
---|
1762 | goto next_skb; |
---|
1763 | } else if (st->root_skb == st->cur_skb && |
---|
1764 | skb_shinfo(st->root_skb)->frag_list) { |
---|
1765 | st->cur_skb = skb_shinfo(st->root_skb)->frag_list; |
---|
1766 | goto next_skb; |
---|
1767 | } |
---|
1768 | |
---|
1769 | return 0; |
---|
1770 | } |
---|
1771 | |
---|
1772 | /** |
---|
1773 | * skb_abort_seq_read - Abort a sequential read of skb data |
---|
1774 | * @st: state variable |
---|
1775 | * |
---|
1776 | * Must be called if skb_seq_read() was not called until it |
---|
1777 | * returned 0. |
---|
1778 | */ |
---|
1779 | void skb_abort_seq_read(struct skb_seq_state *st) |
---|
1780 | { |
---|
1781 | if (st->frag_data) |
---|
1782 | kunmap_skb_frag(st->frag_data); |
---|
1783 | } |
---|
1784 | |
---|
1785 | #define TS_SKB_CB(state) ((struct skb_seq_state *) &((state)->cb)) |
---|
1786 | |
---|
1787 | static unsigned int skb_ts_get_next_block(unsigned int offset, const u8 **text, |
---|
1788 | struct ts_config *conf, |
---|
1789 | struct ts_state *state) |
---|
1790 | { |
---|
1791 | return skb_seq_read(offset, text, TS_SKB_CB(state)); |
---|
1792 | } |
---|
1793 | |
---|
1794 | static void skb_ts_finish(struct ts_config *conf, struct ts_state *state) |
---|
1795 | { |
---|
1796 | skb_abort_seq_read(TS_SKB_CB(state)); |
---|
1797 | } |
---|
1798 | |
---|
1799 | /** |
---|
1800 | * skb_find_text - Find a text pattern in skb data |
---|
1801 | * @skb: the buffer to look in |
---|
1802 | * @from: search offset |
---|
1803 | * @to: search limit |
---|
1804 | * @config: textsearch configuration |
---|
1805 | * @state: uninitialized textsearch state variable |
---|
1806 | * |
---|
1807 | * Finds a pattern in the skb data according to the specified |
---|
1808 | * textsearch configuration. Use textsearch_next() to retrieve |
---|
1809 | * subsequent occurrences of the pattern. Returns the offset |
---|
1810 | * to the first occurrence or UINT_MAX if no match was found. |
---|
1811 | */ |
---|
1812 | unsigned int skb_find_text(struct sk_buff *skb, unsigned int from, |
---|
1813 | unsigned int to, struct ts_config *config, |
---|
1814 | struct ts_state *state) |
---|
1815 | { |
---|
1816 | unsigned int ret; |
---|
1817 | |
---|
1818 | config->get_next_block = skb_ts_get_next_block; |
---|
1819 | config->finish = skb_ts_finish; |
---|
1820 | |
---|
1821 | skb_prepare_seq_read(skb, from, to, TS_SKB_CB(state)); |
---|
1822 | |
---|
1823 | ret = textsearch_find(config, state); |
---|
1824 | return (ret <= to - from ? ret : UINT_MAX); |
---|
1825 | } |
---|
1826 | |
---|
1827 | /** |
---|
1828 | * skb_append_datato_frags: - append the user data to a skb |
---|
1829 | * @sk: sock structure |
---|
1830 | * @skb: skb structure to be appened with user data. |
---|
1831 | * @getfrag: call back function to be used for getting the user data |
---|
1832 | * @from: pointer to user message iov |
---|
1833 | * @length: length of the iov message |
---|
1834 | * |
---|
1835 | * Description: This procedure append the user data in the fragment part |
---|
1836 | * of the skb if any page alloc fails user this procedure returns -ENOMEM |
---|
1837 | */ |
---|
1838 | int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb, |
---|
1839 | int (*getfrag)(void *from, char *to, int offset, |
---|
1840 | int len, int odd, struct sk_buff *skb), |
---|
1841 | void *from, int length) |
---|
1842 | { |
---|
1843 | int frg_cnt = 0; |
---|
1844 | skb_frag_t *frag = NULL; |
---|
1845 | struct page *page = NULL; |
---|
1846 | int copy, left; |
---|
1847 | int offset = 0; |
---|
1848 | int ret; |
---|
1849 | |
---|
1850 | do { |
---|
1851 | /* Return error if we don't have space for new frag */ |
---|
1852 | frg_cnt = skb_shinfo(skb)->nr_frags; |
---|
1853 | if (frg_cnt >= MAX_SKB_FRAGS) |
---|
1854 | return -EFAULT; |
---|
1855 | |
---|
1856 | /* allocate a new page for next frag */ |
---|
1857 | page = alloc_pages(sk->sk_allocation, 0); |
---|
1858 | |
---|
1859 | /* If alloc_page fails just return failure and caller will |
---|
1860 | * free previous allocated pages by doing kfree_skb() |
---|
1861 | */ |
---|
1862 | if (page == NULL) |
---|
1863 | return -ENOMEM; |
---|
1864 | |
---|
1865 | /* initialize the next frag */ |
---|
1866 | sk->sk_sndmsg_page = page; |
---|
1867 | sk->sk_sndmsg_off = 0; |
---|
1868 | skb_fill_page_desc(skb, frg_cnt, page, 0, 0); |
---|
1869 | skb->truesize += PAGE_SIZE; |
---|
1870 | atomic_add(PAGE_SIZE, &sk->sk_wmem_alloc); |
---|
1871 | |
---|
1872 | /* get the new initialized frag */ |
---|
1873 | frg_cnt = skb_shinfo(skb)->nr_frags; |
---|
1874 | frag = &skb_shinfo(skb)->frags[frg_cnt - 1]; |
---|
1875 | |
---|
1876 | /* copy the user data to page */ |
---|
1877 | left = PAGE_SIZE - frag->page_offset; |
---|
1878 | copy = (length > left)? left : length; |
---|
1879 | |
---|
1880 | ret = getfrag(from, (page_address(frag->page) + |
---|
1881 | frag->page_offset + frag->size), |
---|
1882 | offset, copy, 0, skb); |
---|
1883 | if (ret < 0) |
---|
1884 | return -EFAULT; |
---|
1885 | |
---|
1886 | /* copy was successful so update the size parameters */ |
---|
1887 | sk->sk_sndmsg_off += copy; |
---|
1888 | frag->size += copy; |
---|
1889 | skb->len += copy; |
---|
1890 | skb->data_len += copy; |
---|
1891 | offset += copy; |
---|
1892 | length -= copy; |
---|
1893 | |
---|
1894 | } while (length > 0); |
---|
1895 | |
---|
1896 | return 0; |
---|
1897 | } |
---|
1898 | |
---|
1899 | /** |
---|
1900 | * skb_pull_rcsum - pull skb and update receive checksum |
---|
1901 | * @skb: buffer to update |
---|
1902 | * @start: start of data before pull |
---|
1903 | * @len: length of data pulled |
---|
1904 | * |
---|
1905 | * This function performs an skb_pull on the packet and updates |
---|
1906 | * update the CHECKSUM_HW checksum. It should be used on receive |
---|
1907 | * path processing instead of skb_pull unless you know that the |
---|
1908 | * checksum difference is zero (e.g., a valid IP header) or you |
---|
1909 | * are setting ip_summed to CHECKSUM_NONE. |
---|
1910 | */ |
---|
1911 | unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len) |
---|
1912 | { |
---|
1913 | BUG_ON(len > skb->len); |
---|
1914 | skb->len -= len; |
---|
1915 | BUG_ON(skb->len < skb->data_len); |
---|
1916 | skb_postpull_rcsum(skb, skb->data, len); |
---|
1917 | return skb->data += len; |
---|
1918 | } |
---|
1919 | |
---|
1920 | EXPORT_SYMBOL_GPL(skb_pull_rcsum); |
---|
1921 | |
---|
1922 | /** |
---|
1923 | * skb_segment - Perform protocol segmentation on skb. |
---|
1924 | * @skb: buffer to segment |
---|
1925 | * @features: features for the output path (see dev->features) |
---|
1926 | * |
---|
1927 | * This function performs segmentation on the given skb. It returns |
---|
1928 | * the segment at the given position. It returns NULL if there are |
---|
1929 | * no more segments to generate, or when an error is encountered. |
---|
1930 | */ |
---|
1931 | struct sk_buff *skb_segment(struct sk_buff *skb, int features) |
---|
1932 | { |
---|
1933 | struct sk_buff *segs = NULL; |
---|
1934 | struct sk_buff *tail = NULL; |
---|
1935 | unsigned int mss = skb_shinfo(skb)->gso_size; |
---|
1936 | unsigned int doffset = skb->data - skb->mac.raw; |
---|
1937 | unsigned int offset = doffset; |
---|
1938 | unsigned int headroom; |
---|
1939 | unsigned int len; |
---|
1940 | int sg = features & NETIF_F_SG; |
---|
1941 | int nfrags = skb_shinfo(skb)->nr_frags; |
---|
1942 | int err = -ENOMEM; |
---|
1943 | int i = 0; |
---|
1944 | int pos; |
---|
1945 | |
---|
1946 | __skb_push(skb, doffset); |
---|
1947 | headroom = skb_headroom(skb); |
---|
1948 | pos = skb_headlen(skb); |
---|
1949 | |
---|
1950 | do { |
---|
1951 | struct sk_buff *nskb; |
---|
1952 | skb_frag_t *frag; |
---|
1953 | int hsize; |
---|
1954 | int k; |
---|
1955 | int size; |
---|
1956 | |
---|
1957 | len = skb->len - offset; |
---|
1958 | if (len > mss) |
---|
1959 | len = mss; |
---|
1960 | |
---|
1961 | hsize = skb_headlen(skb) - offset; |
---|
1962 | if (hsize < 0) |
---|
1963 | hsize = 0; |
---|
1964 | if (hsize > len || !sg) |
---|
1965 | hsize = len; |
---|
1966 | |
---|
1967 | nskb = alloc_skb(hsize + doffset + headroom, GFP_ATOMIC); |
---|
1968 | if (unlikely(!nskb)) |
---|
1969 | goto err; |
---|
1970 | |
---|
1971 | if (segs) |
---|
1972 | tail->next = nskb; |
---|
1973 | else |
---|
1974 | segs = nskb; |
---|
1975 | tail = nskb; |
---|
1976 | |
---|
1977 | nskb->dev = skb->dev; |
---|
1978 | nskb->priority = skb->priority; |
---|
1979 | nskb->protocol = skb->protocol; |
---|
1980 | nskb->dst = dst_clone(skb->dst); |
---|
1981 | memcpy(nskb->cb, skb->cb, sizeof(skb->cb)); |
---|
1982 | nskb->pkt_type = skb->pkt_type; |
---|
1983 | nskb->mac_len = skb->mac_len; |
---|
1984 | |
---|
1985 | skb_reserve(nskb, headroom); |
---|
1986 | nskb->mac.raw = nskb->data; |
---|
1987 | nskb->nh.raw = nskb->data + skb->mac_len; |
---|
1988 | nskb->h.raw = nskb->nh.raw + (skb->h.raw - skb->nh.raw); |
---|
1989 | memcpy(skb_put(nskb, doffset), skb->data, doffset); |
---|
1990 | |
---|
1991 | if (!sg) { |
---|
1992 | nskb->csum = skb_copy_and_csum_bits(skb, offset, |
---|
1993 | skb_put(nskb, len), |
---|
1994 | len, 0); |
---|
1995 | continue; |
---|
1996 | } |
---|
1997 | |
---|
1998 | frag = skb_shinfo(nskb)->frags; |
---|
1999 | k = 0; |
---|
2000 | |
---|
2001 | nskb->ip_summed = CHECKSUM_HW; |
---|
2002 | nskb->csum = skb->csum; |
---|
2003 | memcpy(skb_put(nskb, hsize), skb->data + offset, hsize); |
---|
2004 | |
---|
2005 | while (pos < offset + len) { |
---|
2006 | BUG_ON(i >= nfrags); |
---|
2007 | |
---|
2008 | *frag = skb_shinfo(skb)->frags[i]; |
---|
2009 | get_page(frag->page); |
---|
2010 | size = frag->size; |
---|
2011 | |
---|
2012 | if (pos < offset) { |
---|
2013 | frag->page_offset += offset - pos; |
---|
2014 | frag->size -= offset - pos; |
---|
2015 | } |
---|
2016 | |
---|
2017 | k++; |
---|
2018 | |
---|
2019 | if (pos + size <= offset + len) { |
---|
2020 | i++; |
---|
2021 | pos += size; |
---|
2022 | } else { |
---|
2023 | frag->size -= pos + size - (offset + len); |
---|
2024 | break; |
---|
2025 | } |
---|
2026 | |
---|
2027 | frag++; |
---|
2028 | } |
---|
2029 | |
---|
2030 | skb_shinfo(nskb)->nr_frags = k; |
---|
2031 | nskb->data_len = len - hsize; |
---|
2032 | nskb->len += nskb->data_len; |
---|
2033 | nskb->truesize += nskb->data_len; |
---|
2034 | } while ((offset += len) < skb->len); |
---|
2035 | |
---|
2036 | return segs; |
---|
2037 | |
---|
2038 | err: |
---|
2039 | while ((skb = segs)) { |
---|
2040 | segs = skb->next; |
---|
2041 | kfree(skb); |
---|
2042 | } |
---|
2043 | return ERR_PTR(err); |
---|
2044 | } |
---|
2045 | |
---|
2046 | EXPORT_SYMBOL_GPL(skb_segment); |
---|
2047 | |
---|
2048 | void __init skb_init(void) |
---|
2049 | { |
---|
2050 | skbuff_head_cache = kmem_cache_create("skbuff_head_cache", |
---|
2051 | sizeof(struct sk_buff), |
---|
2052 | 0, |
---|
2053 | SLAB_HWCACHE_ALIGN, |
---|
2054 | NULL, NULL); |
---|
2055 | if (!skbuff_head_cache) |
---|
2056 | panic("cannot create skbuff cache"); |
---|
2057 | |
---|
2058 | skbuff_fclone_cache = kmem_cache_create("skbuff_fclone_cache", |
---|
2059 | (2*sizeof(struct sk_buff)) + |
---|
2060 | sizeof(atomic_t), |
---|
2061 | 0, |
---|
2062 | SLAB_HWCACHE_ALIGN, |
---|
2063 | NULL, NULL); |
---|
2064 | if (!skbuff_fclone_cache) |
---|
2065 | panic("cannot create skbuff cache"); |
---|
2066 | } |
---|
2067 | |
---|
2068 | EXPORT_SYMBOL(___pskb_trim); |
---|
2069 | EXPORT_SYMBOL(__kfree_skb); |
---|
2070 | EXPORT_SYMBOL(kfree_skb); |
---|
2071 | EXPORT_SYMBOL(__pskb_pull_tail); |
---|
2072 | EXPORT_SYMBOL(__alloc_skb); |
---|
2073 | EXPORT_SYMBOL(__netdev_alloc_skb); |
---|
2074 | EXPORT_SYMBOL(pskb_copy); |
---|
2075 | EXPORT_SYMBOL(pskb_expand_head); |
---|
2076 | EXPORT_SYMBOL(skb_checksum); |
---|
2077 | EXPORT_SYMBOL(skb_clone); |
---|
2078 | EXPORT_SYMBOL(skb_clone_fraglist); |
---|
2079 | EXPORT_SYMBOL(skb_copy); |
---|
2080 | EXPORT_SYMBOL(skb_copy_and_csum_bits); |
---|
2081 | EXPORT_SYMBOL(skb_copy_and_csum_dev); |
---|
2082 | EXPORT_SYMBOL(skb_copy_bits); |
---|
2083 | EXPORT_SYMBOL(skb_copy_expand); |
---|
2084 | EXPORT_SYMBOL(skb_over_panic); |
---|
2085 | EXPORT_SYMBOL(skb_pad); |
---|
2086 | EXPORT_SYMBOL(skb_realloc_headroom); |
---|
2087 | EXPORT_SYMBOL(skb_under_panic); |
---|
2088 | EXPORT_SYMBOL(skb_dequeue); |
---|
2089 | EXPORT_SYMBOL(skb_dequeue_tail); |
---|
2090 | EXPORT_SYMBOL(skb_insert); |
---|
2091 | EXPORT_SYMBOL(skb_queue_purge); |
---|
2092 | EXPORT_SYMBOL(skb_queue_head); |
---|
2093 | EXPORT_SYMBOL(skb_queue_tail); |
---|
2094 | EXPORT_SYMBOL(skb_unlink); |
---|
2095 | EXPORT_SYMBOL(skb_append); |
---|
2096 | EXPORT_SYMBOL(skb_split); |
---|
2097 | EXPORT_SYMBOL(skb_prepare_seq_read); |
---|
2098 | EXPORT_SYMBOL(skb_seq_read); |
---|
2099 | EXPORT_SYMBOL(skb_abort_seq_read); |
---|
2100 | EXPORT_SYMBOL(skb_find_text); |
---|
2101 | EXPORT_SYMBOL(skb_append_datato_frags); |
---|