1 | /* |
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2 | * |
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3 | * Copyright (c) 2007-2016 The University of Waikato, Hamilton, New Zealand. |
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4 | * All rights reserved. |
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5 | * |
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6 | * This file is part of libtrace. |
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7 | * |
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8 | * This code has been developed by the University of Waikato WAND |
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9 | * research group. For further information please see http://www.wand.net.nz/ |
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10 | * |
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11 | * libtrace is free software; you can redistribute it and/or modify |
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12 | * it under the terms of the GNU Lesser General Public License as published by |
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13 | * the Free Software Foundation; either version 3 of the License, or |
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14 | * (at your option) any later version. |
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15 | * |
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16 | * libtrace is distributed in the hope that it will be useful, |
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17 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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18 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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19 | * GNU Lesser General Public License for more details. |
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20 | * |
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21 | * You should have received a copy of the GNU Lesser General Public License |
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22 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
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23 | * |
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24 | * |
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25 | */ |
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26 | |
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27 | |
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28 | #include "config.h" |
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29 | #include <stdlib.h> |
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30 | #include <string.h> |
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31 | #include <stdio.h> |
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32 | #include <assert.h> |
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33 | #include <arpa/inet.h> |
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34 | #include "Anon.h" |
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35 | |
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36 | |
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37 | static uint32_t masks[33] = { |
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38 | 0x00000000, 0x80000000, 0xC0000000, 0xe0000000, 0xf0000000, |
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39 | 0xf8000000, 0xfC000000, 0xfe000000, 0xff000000, 0xff800000, |
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40 | 0xffC00000, 0xffe00000, 0xfff00000, 0xfff80000, 0xfffC0000, |
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41 | 0xfffe0000, 0xffff0000, 0xffff8000, 0xffffC000, 0xffffe000, |
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42 | 0xfffff000, 0xfffff800, 0xfffffC00, 0xfffffe00, 0xffffff00, |
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43 | 0xffffff80, 0xffffffC0, 0xffffffe0, 0xfffffff0, 0xfffffff8, |
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44 | 0xfffffffC, 0xfffffffe, 0xffffffff, |
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45 | }; |
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46 | |
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47 | |
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48 | Anonymiser::Anonymiser () { |
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49 | /* empty constructor */ |
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50 | } |
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51 | |
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52 | PrefixSub::PrefixSub(const char *ipv4_key, const char *ipv6_key) : Anonymiser() { |
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53 | this->ipv4_mask = 0; |
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54 | this->ipv4_prefix = 0; |
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55 | |
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56 | memset(this->ipv6_mask, 0, 16); |
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57 | memset(this->ipv6_prefix, 0, 16); |
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58 | |
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59 | if (ipv4_key != NULL) { |
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60 | int a,b,c,d; |
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61 | int bits; |
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62 | |
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63 | if (sscanf(ipv4_key, "%i.%i.%i.%i/%i", &a, &b, &c, &d, &bits) != 5) { |
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64 | fprintf(stderr, "Invalid IPv4 prefix: %s\n", ipv4_key); |
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65 | |
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66 | } else { |
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67 | this->ipv4_prefix = (a<<24) + (b<<16) + (c<<8) + d; |
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68 | if (bits < 0 || bits > 32) { |
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69 | fprintf(stderr, "Invalid IPv4 prefix: %s\n", ipv4_key); |
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70 | } else { |
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71 | this->ipv4_mask = masks[bits]; |
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72 | } |
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73 | } |
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74 | } |
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75 | |
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76 | /* TODO IPv6 */ |
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77 | |
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78 | |
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79 | } |
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80 | |
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81 | PrefixSub::~PrefixSub() { |
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82 | |
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83 | } |
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84 | |
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85 | uint32_t PrefixSub::anonIPv4(uint32_t orig) { |
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86 | |
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87 | return (this->ipv4_prefix & this->ipv4_mask) | (orig & ~this->ipv4_mask); |
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88 | |
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89 | } |
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90 | |
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91 | void PrefixSub::anonIPv6(uint8_t *orig, uint8_t *result) { |
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92 | |
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93 | /* TODO */ |
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94 | memcpy(result, orig, 16); |
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95 | |
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96 | } |
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97 | |
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98 | #ifdef HAVE_LIBCRYPTO |
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99 | #include <openssl/evp.h> |
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100 | |
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101 | CryptoAnon::CryptoAnon(uint8_t *key, uint8_t len, uint8_t cachebits) : |
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102 | Anonymiser() { |
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103 | |
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104 | assert(len >= 32); |
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105 | memcpy(this->key, key, 16); |
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106 | memcpy(this->padding, key + 16, 16); |
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107 | |
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108 | this->cipher = EVP_aes_128_ecb(); |
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109 | this->ctx = EVP_CIPHER_CTX_new(); |
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110 | EVP_CIPHER_CTX_init(this->ctx); |
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111 | |
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112 | EVP_EncryptInit_ex(this->ctx, this->cipher, NULL, this->key, NULL); |
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113 | |
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114 | this->cachebits = cachebits; |
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115 | |
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116 | this->ipv4_cache = new IPv4AnonCache(); |
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117 | this->ipv6_cache = new IPv6AnonCache(); |
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118 | this->recent_ipv4_cache[0][0] = 0; |
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119 | this->recent_ipv4_cache[0][1] = 0; |
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120 | this->recent_ipv4_cache[1][0] = 0; |
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121 | this->recent_ipv4_cache[0][1] = 0; |
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122 | |
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123 | } |
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124 | |
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125 | |
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126 | CryptoAnon::~CryptoAnon() { |
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127 | delete(this->ipv4_cache); |
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128 | EVP_CIPHER_CTX_cleanup(this->ctx); |
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129 | EVP_CIPHER_CTX_free(this->ctx); |
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130 | } |
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131 | |
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132 | static inline uint32_t generateFirstPad(uint8_t *pad) { |
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133 | uint32_t fp = 0; |
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134 | |
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135 | fp = (((uint32_t)pad[0]) << 24) + (((uint32_t)pad[1]) << 16) + |
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136 | (((uint32_t)pad[2]) << 8) + (uint32_t)pad[3]; |
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137 | return fp; |
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138 | |
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139 | } |
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140 | |
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141 | uint32_t CryptoAnon::anonIPv4(uint32_t orig) { |
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142 | uint32_t cacheprefix = |
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143 | (orig >> (32 - this->cachebits)) << (32 - this->cachebits); |
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144 | uint32_t result = 0; |
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145 | |
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146 | if (this->recent_ipv4_cache[0][0] == orig) |
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147 | return this->recent_ipv4_cache[0][1]; |
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148 | else if (this->recent_ipv4_cache[1][0] == orig) { |
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149 | uint32_t tmp = this->recent_ipv4_cache[1][1]; |
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150 | this->recent_ipv4_cache[1][0] = this->recent_ipv4_cache[0][0]; |
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151 | this->recent_ipv4_cache[1][1] = this->recent_ipv4_cache[0][1]; |
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152 | this->recent_ipv4_cache[0][0] = orig; |
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153 | this->recent_ipv4_cache[0][1] = tmp; |
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154 | return tmp; |
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155 | |
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156 | } |
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157 | |
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158 | result = this->lookupv4Cache(cacheprefix); |
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159 | result = this->encrypt32Bits(orig, this->cachebits, 32, result); |
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160 | |
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161 | this->recent_ipv4_cache[1][0] = this->recent_ipv4_cache[0][0]; |
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162 | this->recent_ipv4_cache[1][1] = this->recent_ipv4_cache[0][1]; |
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163 | this->recent_ipv4_cache[0][0] = orig; |
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164 | this->recent_ipv4_cache[0][1] = result ^ orig; |
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165 | |
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166 | return this->recent_ipv4_cache[0][1]; |
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167 | } |
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168 | |
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169 | static uint64_t swap64(uint64_t num) { |
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170 | uint32_t swapa, swapb; |
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171 | uint64_t res; |
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172 | |
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173 | swapa = (num & 0xffffffff); |
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174 | swapb = (num >> 32); |
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175 | swapa = ntohl(swapa); |
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176 | swapb = ntohl(swapb); |
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177 | res =(uint64_t)swapa << 32 | (swapb); |
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178 | return res; |
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179 | } |
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180 | |
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181 | void CryptoAnon::anonIPv6(uint8_t *orig, uint8_t *result) { |
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182 | |
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183 | uint64_t prefix, anonprefixmap; |
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184 | uint64_t suffix, anonsuffixmap; |
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185 | |
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186 | memcpy(&prefix, orig, 8); |
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187 | memcpy(&suffix, orig + 8, 8); |
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188 | |
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189 | prefix = swap64(prefix); |
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190 | suffix = swap64(suffix); |
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191 | |
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192 | anonprefixmap = this->lookupv6Cache(prefix); |
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193 | anonsuffixmap = this->lookupv6Cache(suffix); |
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194 | |
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195 | prefix = (swap64(anonprefixmap ^ prefix)); |
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196 | suffix = (swap64(anonsuffixmap ^ suffix)); |
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197 | |
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198 | memcpy(result, &prefix, sizeof(uint64_t)); |
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199 | memcpy(result + sizeof(uint64_t), &suffix, sizeof(uint64_t)); |
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200 | |
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201 | } |
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202 | |
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203 | uint32_t CryptoAnon::lookupv4Cache(uint32_t prefix) { |
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204 | |
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205 | IPv4AnonCache::iterator it = this->ipv4_cache->find(prefix); |
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206 | |
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207 | if (it == this->ipv4_cache->end()) { |
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208 | uint32_t prefmask = this->encrypt32Bits(prefix, 0, this->cachebits, 0); |
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209 | (*this->ipv4_cache)[prefix] = prefmask; |
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210 | return prefmask; |
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211 | } |
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212 | return it->second; |
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213 | |
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214 | } |
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215 | |
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216 | uint64_t CryptoAnon::lookupv6Cache(uint64_t prefix) { |
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217 | IPv6AnonCache::iterator it = this->ipv6_cache->find(prefix); |
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218 | |
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219 | if (it == this->ipv6_cache->end()) { |
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220 | uint64_t prefmask = this->encrypt64Bits(prefix); |
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221 | (*this->ipv6_cache)[prefix] = prefmask; |
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222 | return prefmask; |
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223 | } |
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224 | return it->second; |
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225 | } |
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226 | |
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227 | uint32_t CryptoAnon::encrypt32Bits(uint32_t orig, uint8_t start, uint8_t stop, |
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228 | uint32_t res) { |
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229 | uint8_t rin_output[32]; |
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230 | uint8_t rin_input[16]; |
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231 | uint32_t first4pad; |
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232 | int outl = 32; |
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233 | |
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234 | memcpy(rin_input, this->padding, 16); |
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235 | first4pad = generateFirstPad(this->padding); |
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236 | |
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237 | for (int pos = start; pos < stop; pos ++) { |
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238 | uint32_t input; |
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239 | |
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240 | /* The MS bits are taken from the original address. The remaining |
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241 | * bits are taken from padding. first4pad is used to help ensure we |
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242 | * use the right bits from padding when pos < 32. |
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243 | */ |
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244 | if (pos == 0) { |
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245 | input = first4pad; |
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246 | } else { |
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247 | input = ((orig >> (32 - pos)) << (32 - pos)) | |
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248 | ((first4pad << pos) >> pos); |
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249 | } |
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250 | |
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251 | rin_input[0] = (uint8_t) (input >> 24); |
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252 | rin_input[1] = (uint8_t) ((input << 8) >> 24); |
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253 | rin_input[2] = (uint8_t) ((input << 16) >> 24); |
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254 | rin_input[3] = (uint8_t) ((input << 24) >> 24); |
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255 | |
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256 | /* Encryption: we're using AES as a pseudorandom function. For each |
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257 | * bit in the original address, we use the first bit of the resulting |
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258 | * encrypted output as part of an XOR mask */ |
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259 | EVP_EncryptUpdate(this->ctx, (unsigned char *)rin_output, &outl, |
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260 | (unsigned char *)rin_input, 16); |
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261 | |
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262 | /* Put the first bit of the output into the right slot of our mask */ |
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263 | res |= (((uint32_t)rin_output[0]) >> 7) << (31 - pos); |
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264 | |
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265 | } |
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266 | return res; |
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267 | |
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268 | } |
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269 | |
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270 | uint64_t CryptoAnon::encrypt64Bits(uint64_t orig) { |
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271 | |
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272 | /* See encrypt32Bits for more explanation of how this works */ |
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273 | uint8_t rin_output[32]; |
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274 | uint8_t rin_input[16]; |
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275 | uint64_t first8pad; |
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276 | int outl = 32; |
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277 | uint64_t result = 0; |
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278 | |
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279 | memcpy(rin_input, this->padding, 16); |
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280 | memcpy(&first8pad, this->padding, 8); |
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281 | |
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282 | for (int pos = 0; pos < 64; pos ++) { |
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283 | uint64_t input; |
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284 | |
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285 | if (pos == 0) { |
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286 | input = first8pad; |
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287 | } else { |
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288 | input = ((orig >> (64 - pos)) << (64 - pos)) | |
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289 | ((first8pad << pos) >> pos); |
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290 | } |
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291 | |
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292 | memcpy(rin_input, &input, 8); |
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293 | |
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294 | EVP_EncryptUpdate(this->ctx, (unsigned char *)rin_output, &outl, |
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295 | (unsigned char *)rin_input, 16); |
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296 | |
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297 | result |= ((((uint64_t)rin_output[0]) >> 7) << (63 - pos)); |
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298 | } |
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299 | |
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300 | return result; |
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301 | } |
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302 | |
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303 | #endif |
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304 | |
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305 | // vim: set sw=4 tabstop=4 softtabstop=4 expandtab : |
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