1 | /*
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2 | * Copyright (c) 2012 Jiri Svoboda
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3 | * All rights reserved.
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4 | *
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5 | * Redistribution and use in source and binary forms, with or without
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6 | * modification, are permitted provided that the following conditions
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7 | * are met:
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8 | *
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9 | * - Redistributions of source code must retain the above copyright
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10 | * notice, this list of conditions and the following disclaimer.
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11 | * - Redistributions in binary form must reproduce the above copyright
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12 | * notice, this list of conditions and the following disclaimer in the
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13 | * documentation and/or other materials provided with the distribution.
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14 | * - The name of the author may not be used to endorse or promote products
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15 | * derived from this software without specific prior written permission.
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16 | *
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17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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27 | */
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28 |
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29 | /** @addtogroup inet
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30 | * @{
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31 | */
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32 | /**
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33 | * @file
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34 | * @brief
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35 | */
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36 |
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37 | #include <align.h>
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38 | #include <bitops.h>
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39 | #include <byteorder.h>
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40 | #include <errno.h>
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41 | #include <fibril_synch.h>
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42 | #include <io/log.h>
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43 | #include <mem.h>
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44 | #include <stdlib.h>
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45 |
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46 | #include "inet.h"
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47 | #include "inet_std.h"
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48 | #include "pdu.h"
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49 |
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50 | static FIBRIL_MUTEX_INITIALIZE(ip_ident_lock);
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51 | static uint16_t ip_ident = 0;
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52 |
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53 | #define INET_CHECKSUM_INIT 0xffff
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54 |
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55 | /** One's complement addition.
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56 | *
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57 | * Result is a + b + carry.
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58 | */
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59 | static uint16_t inet_ocadd16(uint16_t a, uint16_t b)
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60 | {
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61 | uint32_t s;
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62 |
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63 | s = (uint32_t)a + (uint32_t)b;
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64 | return (s & 0xffff) + (s >> 16);
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65 | }
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66 |
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67 | static uint16_t inet_checksum_calc(uint16_t ivalue, void *data, size_t size)
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68 | {
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69 | uint16_t sum;
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70 | uint16_t w;
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71 | size_t words, i;
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72 | uint8_t *bdata;
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73 |
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74 | sum = ~ivalue;
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75 | words = size / 2;
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76 | bdata = (uint8_t *)data;
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77 |
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78 | for (i = 0; i < words; i++) {
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79 | w = ((uint16_t)bdata[2*i] << 8) | bdata[2*i + 1];
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80 | sum = inet_ocadd16(sum, w);
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81 | }
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82 |
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83 | if (size % 2 != 0) {
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84 | w = ((uint16_t)bdata[2*words] << 8);
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85 | sum = inet_ocadd16(sum, w);
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86 | }
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87 |
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88 | return ~sum;
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89 | }
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90 |
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91 | /** Encode Internet PDU.
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92 | */
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93 | int inet_pdu_encode(inet_packet_t *packet, void **rdata, size_t *rsize)
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94 | {
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95 | void *data;
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96 | size_t size;
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97 | ip_header_t *hdr;
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98 | size_t hdr_size;
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99 | size_t data_offs;
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100 | uint16_t chksum;
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101 | uint16_t ident;
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102 |
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103 | fibril_mutex_lock(&ip_ident_lock);
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104 | ident = ++ip_ident;
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105 | fibril_mutex_unlock(&ip_ident_lock);
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106 |
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107 | hdr_size = sizeof(ip_header_t);
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108 | size = hdr_size + packet->size;
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109 | data_offs = ROUND_UP(hdr_size, 4);
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110 |
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111 | data = calloc(size, 1);
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112 | if (data == NULL)
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113 | return ENOMEM;
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114 |
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115 | hdr = (ip_header_t *)data;
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116 | hdr->ver_ihl = (4 << VI_VERSION_l) | (hdr_size / sizeof(uint32_t));
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117 | hdr->tos = packet->tos;
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118 | hdr->tot_len = host2uint16_t_be(size);
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119 | hdr->id = host2uint16_t_be(ident);
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120 | hdr->flags_foff = host2uint16_t_be(packet->df ?
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121 | BIT_V(uint16_t, FF_FLAG_DF) : 0);
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122 | hdr->ttl = packet->ttl;
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123 | hdr->proto = packet->proto;
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124 | hdr->chksum = 0;
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125 | hdr->src_addr = host2uint32_t_be(packet->src.ipv4);
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126 | hdr->dest_addr = host2uint32_t_be(packet->dest.ipv4);
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127 |
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128 | chksum = inet_checksum_calc(INET_CHECKSUM_INIT, (void *)hdr, hdr_size);
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129 | hdr->chksum = host2uint16_t_be(chksum);
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130 |
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131 | memcpy((uint8_t *)data + data_offs, packet->data, packet->size);
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132 |
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133 | *rdata = data;
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134 | *rsize = size;
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135 | return EOK;
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136 | }
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137 |
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138 | int inet_pdu_decode(void *data, size_t size, inet_packet_t *packet)
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139 | {
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140 | ip_header_t *hdr;
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141 | size_t tot_len;
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142 | size_t data_offs;
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143 | uint8_t version;
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144 | uint16_t ident;
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145 |
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146 | log_msg(LVL_DEBUG, "inet_pdu_decode()");
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147 |
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148 | if (size < sizeof(ip_header_t)) {
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149 | log_msg(LVL_DEBUG, "PDU too short (%zu)", size);
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150 | return EINVAL;
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151 | }
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152 |
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153 | hdr = (ip_header_t *)data;
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154 |
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155 | version = BIT_RANGE_EXTRACT(uint8_t, VI_VERSION_h, VI_VERSION_l,
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156 | hdr->ver_ihl);
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157 | if (version != 4) {
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158 | log_msg(LVL_DEBUG, "Version (%d) != 4", version);
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159 | return EINVAL;
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160 | }
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161 |
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162 | tot_len = uint16_t_be2host(hdr->tot_len);
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163 | if (tot_len < sizeof(ip_header_t)) {
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164 | log_msg(LVL_DEBUG, "Total Length too small (%zu)", tot_len);
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165 | return EINVAL;
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166 | }
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167 |
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168 | if (tot_len > size) {
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169 | log_msg(LVL_DEBUG, "Total Length = %zu > PDU size = %zu",
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170 | tot_len, size);
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171 | return EINVAL;
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172 | }
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173 |
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174 | ident = uint16_t_be2host(hdr->id);
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175 | (void)ident;
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176 | /* XXX Flags */
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177 | /* XXX Fragment offset */
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178 | /* XXX Checksum */
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179 |
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180 | packet->src.ipv4 = uint32_t_be2host(hdr->src_addr);
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181 | packet->dest.ipv4 = uint32_t_be2host(hdr->dest_addr);
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182 | packet->tos = hdr->tos;
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183 | packet->proto = hdr->proto;
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184 | packet->ttl = hdr->ttl;
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185 | packet->df = (uint16_t_be2host(hdr->tos) & BIT_V(uint16_t, FF_FLAG_DF))
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186 | ? 1 : 0;
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187 |
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188 | /* XXX IP options */
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189 | data_offs = sizeof(uint32_t) * BIT_RANGE_EXTRACT(uint8_t, VI_IHL_h,
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190 | VI_IHL_l, hdr->ver_ihl);
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191 |
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192 | packet->size = tot_len - data_offs;
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193 | packet->data = calloc(packet->size, 1);
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194 | if (packet->data == NULL) {
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195 | log_msg(LVL_WARN, "Out of memory.");
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196 | return ENOMEM;
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197 | }
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198 |
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199 | memcpy(packet->data, (uint8_t *)data + data_offs, packet->size);
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200 |
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201 | return EOK;
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202 | }
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203 |
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204 | /** @}
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205 | */
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