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 | #include "libtrace_int.h" |
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27 | #include "libtrace.h" |
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28 | #include "protocols.h" |
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29 | #include <stdlib.h> |
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30 | #include <string.h> |
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31 | |
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32 | |
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33 | /* This file contains all the protocol decoding functions for layer 2 |
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34 | * (and 2.5) protocols. This includes functions for accessing MAC addresses. |
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35 | * |
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36 | * Supported protocols include (but are not limited to): |
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37 | * Ethernet |
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38 | * 802.11 |
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39 | * 802.1q (vlan) |
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40 | * MPLS |
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41 | * PPPoE |
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42 | * LLCSnap |
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43 | * ATM |
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44 | */ |
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45 | |
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46 | |
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47 | /* Returns the payload from 802.3 ethernet. Type optionally returned in |
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48 | * "type" in host byte order. This will return a vlan header. |
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49 | */ |
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50 | void *trace_get_payload_from_ethernet(void *ethernet, |
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51 | uint16_t *type, |
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52 | uint32_t *remaining) |
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53 | { |
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54 | libtrace_ether_t *eth = (libtrace_ether_t*)ethernet; |
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55 | |
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56 | if (remaining) { |
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57 | if (*remaining < sizeof(*eth)) { |
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58 | *remaining = 0; |
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59 | return NULL; |
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60 | } |
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61 | *remaining-=sizeof(*eth); |
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62 | } |
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63 | |
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64 | if (type) |
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65 | *type = ntohs(eth->ether_type); |
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66 | |
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67 | return (void*)((char *)eth + sizeof(*eth)); |
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68 | } |
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69 | |
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70 | /* Skip any 802.1q headers if necessary |
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71 | * type is now output only (why check it if we don't need to?) |
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72 | */ |
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73 | void *trace_get_payload_from_vlan(void *ethernet, uint16_t *type, |
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74 | uint32_t *remaining) |
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75 | { |
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76 | libtrace_8021q_t *vlanhdr = (libtrace_8021q_t *)ethernet; |
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77 | |
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78 | if (remaining) { |
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79 | if (*remaining < sizeof(libtrace_8021q_t)) { |
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80 | *remaining = 0; |
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81 | return NULL; |
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82 | } |
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83 | |
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84 | *remaining=*remaining-sizeof(libtrace_8021q_t); |
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85 | } |
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86 | |
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87 | if (type) |
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88 | *type = ntohs(vlanhdr->vlan_ether_type); |
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89 | |
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90 | return (void*)((char *)ethernet + sizeof(*vlanhdr)); |
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91 | |
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92 | } |
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93 | |
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94 | int trace_destroy_layer2_headers(libtrace_layer2_headers_t *headers) { |
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95 | if (headers == NULL) { |
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96 | fprintf(stderr, "NULL libtrace_layer2_headers_t passed into " |
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97 | "trace_destroy_layer2_headers()\n"); |
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98 | return -1; |
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99 | } |
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100 | |
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101 | if (headers->header != NULL) { |
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102 | free(headers->header); |
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103 | } |
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104 | free(headers); |
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105 | return 1; |
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106 | } |
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107 | libtrace_layer2_headers_t *trace_get_layer2_headers(libtrace_packet_t *packet) { |
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108 | |
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109 | char *ptr; |
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110 | libtrace_linktype_t linktype; |
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111 | uint32_t remaining; |
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112 | uint16_t ethertype; |
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113 | libtrace_layer2_headers_t *r; |
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114 | |
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115 | if (packet == NULL) { |
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116 | fprintf(stderr, "NULL packet passed into trace_get_layer2_headers()\n"); |
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117 | return NULL; |
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118 | } |
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119 | if (packet->trace == NULL) { |
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120 | fprintf(stderr, "Packet contains a NULL trace in trace_get_layer2_headers()\n"); |
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121 | return NULL; |
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122 | } |
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123 | |
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124 | /* jump to layer 2 */ |
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125 | ptr = trace_get_layer2(packet, &linktype, &remaining); |
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126 | /* packet does not contain layer2 */ |
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127 | if (ptr == NULL) { |
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128 | return NULL; |
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129 | } |
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130 | |
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131 | /* allocate memory for the result */ |
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132 | r = calloc(1, sizeof(libtrace_layer2_headers_t)); |
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133 | if (r == NULL) { |
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134 | trace_set_err(packet->trace, TRACE_ERR_OUT_OF_MEMORY, |
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135 | "Unable to allocate memory in trace_get_layer2_headers()\n"); |
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136 | return NULL; |
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137 | } |
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138 | r->header = calloc(1, sizeof(libtrace_layer2_header_t)); |
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139 | if (r->header == NULL) { |
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140 | trace_set_err(packet->trace, TRACE_ERR_OUT_OF_MEMORY, |
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141 | "Unable to allocate memory in trace_get_layer2_headers()\n"); |
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142 | free(r); |
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143 | return NULL; |
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144 | } |
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145 | |
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146 | /* get the first layer2 header */ |
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147 | ptr = trace_get_payload_from_layer2(ptr, linktype, ðertype, &remaining); |
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148 | |
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149 | while (remaining != 0 && ptr != NULL) { |
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150 | |
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151 | if (ethertype == TRACE_ETHERTYPE_LOOPBACK || |
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152 | ethertype == TRACE_ETHERTYPE_IP || |
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153 | ethertype == TRACE_ETHERTYPE_ARP || |
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154 | ethertype == TRACE_ETHERTYPE_RARP || |
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155 | ethertype == TRACE_ETHERTYPE_8021Q || |
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156 | ethertype == TRACE_ETHERTYPE_IPV6 || |
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157 | ethertype == TRACE_ETHERTYPE_8021QS || |
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158 | ethertype == TRACE_ETHERTYPE_MPLS || |
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159 | ethertype == TRACE_ETHERTYPE_MPLS_MC || |
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160 | ethertype == TRACE_ETHERTYPE_PPP_DISC || |
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161 | ethertype == TRACE_ETHERTYPE_PPP_SES) { |
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162 | |
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163 | /* Set the bitmask */ |
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164 | switch (ethertype) { |
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165 | case (TRACE_ETHERTYPE_LOOPBACK): |
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166 | r->bitmask |= TRACE_BITMASK_LOOPBACK; |
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167 | break; |
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168 | case (TRACE_ETHERTYPE_IP): |
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169 | r->bitmask |= TRACE_BITMASK_IP; |
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170 | break; |
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171 | case (TRACE_ETHERTYPE_ARP): |
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172 | r->bitmask |= TRACE_BITMASK_ARP; |
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173 | break; |
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174 | case (TRACE_ETHERTYPE_RARP): |
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175 | r->bitmask |= TRACE_BITMASK_RARP; |
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176 | break; |
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177 | case (TRACE_ETHERTYPE_8021Q): |
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178 | r->bitmask |= TRACE_BITMASK_8021Q; |
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179 | break; |
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180 | case (TRACE_ETHERTYPE_IPV6): |
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181 | r->bitmask |= TRACE_BITMASK_IPV6; |
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182 | break; |
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183 | case (TRACE_ETHERTYPE_8021QS): |
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184 | r->bitmask |= TRACE_BITMASK_8021QS; |
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185 | break; |
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186 | case (TRACE_ETHERTYPE_MPLS): |
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187 | r->bitmask |= TRACE_BITMASK_MPLS; |
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188 | break; |
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189 | case (TRACE_ETHERTYPE_MPLS_MC): |
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190 | r->bitmask |= TRACE_BITMASK_MPLS_MC; |
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191 | break; |
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192 | case (TRACE_ETHERTYPE_PPP_DISC): |
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193 | r->bitmask |= TRACE_BITMASK_PPP_DISC; |
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194 | break; |
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195 | case (TRACE_ETHERTYPE_PPP_SES): |
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196 | r->bitmask |= TRACE_BITMASK_PPP_SES; |
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197 | break; |
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198 | } |
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199 | |
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200 | r->header = realloc(r->header, |
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201 | sizeof(libtrace_layer2_header_t)*(r->num+1)); |
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202 | r->header[r->num].ethertype = ethertype; |
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203 | r->header[r->num++].data = ptr; |
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204 | } |
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205 | |
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206 | /* if the last ethertype was IP stop */ |
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207 | if (ethertype == TRACE_ETHERTYPE_IP || ethertype == TRACE_ETHERTYPE_IPV6) { |
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208 | break; |
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209 | } |
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210 | |
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211 | /* get the next header */ |
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212 | ptr = trace_get_payload_from_layer2(ptr, linktype, ðertype, &remaining); |
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213 | } |
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214 | |
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215 | /* If no results were found free memory now and just return NULL */ |
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216 | if (r->num) { |
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217 | free(r->header); |
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218 | free(r); |
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219 | return NULL; |
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220 | } |
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221 | |
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222 | return r; |
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223 | } |
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224 | |
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225 | uint16_t trace_get_outermost_vlan(libtrace_packet_t *packet, uint8_t **vlanptr, |
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226 | uint32_t *remaining) { |
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227 | |
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228 | uint8_t *ptr; |
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229 | libtrace_linktype_t linktype; |
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230 | uint32_t rem; |
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231 | uint16_t vlanid = VLAN_NOT_FOUND; |
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232 | uint16_t ethertype = 0; |
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233 | |
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234 | if (!packet) { |
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235 | fprintf(stderr, "NULL packet passed into trace_get_outermost_vlan()\n"); |
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236 | *vlanptr = NULL; |
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237 | *remaining = rem; |
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238 | return vlanid; |
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239 | } |
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240 | |
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241 | ptr = trace_get_layer2(packet, &linktype, &rem); |
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242 | /* No layer 2 */ |
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243 | if (ptr == NULL) { |
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244 | *vlanptr = NULL; |
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245 | *remaining = rem; |
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246 | return vlanid; |
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247 | } |
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248 | |
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249 | while (ethertype != TRACE_ETHERTYPE_8021Q && ethertype != TRACE_ETHERTYPE_8021QS) { |
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250 | |
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251 | if (rem == 0 || ptr == NULL || ethertype == TRACE_ETHERTYPE_IP || |
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252 | ethertype == TRACE_ETHERTYPE_IPV6) { |
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253 | |
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254 | *vlanptr = NULL; |
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255 | *remaining = rem; |
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256 | return vlanid; |
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257 | } |
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258 | |
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259 | /* get the next layer 2 header */ |
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260 | ptr = trace_get_payload_from_layer2(ptr, linktype, ðertype, &rem); |
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261 | } |
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262 | |
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263 | /* found a vlan header */ |
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264 | uint32_t val = ntohl(*(uint32_t *)ptr); |
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265 | /* the id portion is only 12 bits */ |
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266 | vlanid = (((val >> 16) << 4) >> 4); |
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267 | |
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268 | *remaining = rem; |
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269 | *vlanptr = ptr; |
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270 | return vlanid; |
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271 | } |
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272 | |
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273 | uint32_t trace_get_outermost_mpls(libtrace_packet_t *packet, uint8_t **mplsptr, |
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274 | uint32_t *remaining) { |
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275 | |
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276 | uint8_t *ptr; |
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277 | uint32_t mplslabel = MPLS_NOT_FOUND; |
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278 | libtrace_linktype_t linktype; |
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279 | uint32_t rem; |
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280 | uint16_t ethertype = 0; |
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281 | |
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282 | if (!packet) { |
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283 | fprintf(stderr, "NULL packet passed into trace_get_outermost_mpls()\n"); |
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284 | *remaining = 0; |
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285 | *mplsptr = NULL; |
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286 | return mplslabel; |
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287 | } |
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288 | |
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289 | ptr = trace_get_layer2(packet, &linktype, &rem); |
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290 | /* No layer2 */ |
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291 | if (ptr == NULL) { |
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292 | *remaining = rem; |
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293 | *mplsptr = NULL; |
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294 | return mplslabel; |
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295 | } |
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296 | |
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297 | /* loop over the packet until we find a mpls label */ |
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298 | while (ethertype != TRACE_ETHERTYPE_MPLS) { |
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299 | if (rem == 0 || ptr == NULL) { |
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300 | |
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301 | *remaining = rem; |
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302 | *mplsptr = NULL; |
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303 | return mplslabel; |
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304 | } |
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305 | |
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306 | /* get next layer2 header */ |
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307 | ptr = trace_get_payload_from_layer2(ptr, linktype, ðertype, &rem); |
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308 | } |
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309 | |
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310 | uint32_t val = ntohl(*(uint32_t *)ptr); |
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311 | mplslabel = val >> 12; |
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312 | |
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313 | *remaining = rem; |
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314 | *mplsptr = ptr; |
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315 | return mplslabel; |
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316 | } |
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317 | |
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318 | libtrace_packet_t *trace_strip_packet(libtrace_packet_t *packet) { |
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319 | |
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320 | libtrace_ether_t *ethernet; |
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321 | libtrace_linktype_t linktype; |
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322 | uint16_t ethertype; |
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323 | uint32_t remaining; |
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324 | char *nextpayload; |
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325 | uint16_t finalethertype = 0; |
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326 | uint16_t caplen, removed = 0; |
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327 | char *dest; |
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328 | uint8_t done = 0; |
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329 | uint32_t oldrem; |
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330 | |
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331 | /* For now, this will just work for Ethernet packets. */ |
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332 | ethernet = (libtrace_ether_t *)trace_get_layer2(packet, |
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333 | &linktype, &remaining); |
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334 | |
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335 | if (linktype != TRACE_TYPE_ETH) { |
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336 | return packet; |
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337 | } |
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338 | |
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339 | /* No headers to strip, return the original packet */ |
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340 | if (ethernet->ether_type == TRACE_ETHERTYPE_IP || |
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341 | ethernet->ether_type == TRACE_ETHERTYPE_IPV6) { |
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342 | return packet; |
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343 | } |
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344 | |
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345 | if (remaining <= sizeof(libtrace_ether_t)) |
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346 | return packet; |
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347 | |
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348 | caplen = trace_get_capture_length(packet); |
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349 | ethertype = ntohs(ethernet->ether_type); |
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350 | dest = ((char *)ethernet) + sizeof(libtrace_ether_t); |
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351 | nextpayload = dest; |
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352 | remaining -= sizeof(libtrace_ether_t); |
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353 | |
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354 | /* I'd normally use trace_get_layer3 here, but it works out faster |
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355 | * to do it this way (mostly less function call overhead). |
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356 | * |
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357 | * XXX This approach is going to just strip everything between the |
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358 | * Ethernet and IP headers -- is there a use case where someone |
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359 | * might want to selectively strip headers? |
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360 | */ |
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361 | while (!done) { |
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362 | |
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363 | if (nextpayload == NULL || remaining == 0) |
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364 | break; |
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365 | |
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366 | oldrem = remaining; |
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367 | switch (ethertype) { |
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368 | |
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369 | case TRACE_ETHERTYPE_8021Q: |
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370 | nextpayload = (char *)trace_get_payload_from_vlan( |
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371 | nextpayload, |
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372 | ðertype, &remaining); |
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373 | removed += (oldrem - remaining); |
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374 | break; |
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375 | |
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376 | case TRACE_ETHERTYPE_MPLS: |
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377 | nextpayload = (char *)trace_get_payload_from_mpls( |
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378 | nextpayload, |
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379 | ðertype, &remaining); |
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380 | removed += (oldrem - remaining); |
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381 | break; |
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382 | case TRACE_ETHERTYPE_PPP_SES: |
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383 | nextpayload = (char *)trace_get_payload_from_pppoe( |
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384 | nextpayload, |
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385 | ðertype, &remaining); |
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386 | removed += (oldrem - remaining); |
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387 | break; |
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388 | |
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389 | case TRACE_ETHERTYPE_IP: |
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390 | case TRACE_ETHERTYPE_IPV6: |
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391 | default: |
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392 | if (finalethertype == 0) |
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393 | finalethertype = ethertype; |
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394 | done = true; |
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395 | break; |
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396 | } |
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397 | } |
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398 | |
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399 | if (nextpayload != NULL && removed > 0) { |
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400 | |
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401 | ethernet->ether_type = ntohs(finalethertype); |
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402 | trace_set_capture_length(packet, caplen - removed); |
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403 | memmove(nextpayload - (dest - (char *)packet->payload), |
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404 | packet->payload, |
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405 | (dest - (char *)packet->payload)); |
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406 | packet->payload = nextpayload - (dest - (char *)packet->payload); |
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407 | packet->cached.l2_header = NULL; |
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408 | } |
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409 | |
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410 | return packet; |
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411 | |
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412 | } |
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413 | |
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414 | /* Skip any MPLS headers if necessary, guessing what the next type is |
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415 | * type is input/output. If the next type is "ethernet" this will |
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416 | * return a type of 0x0000. |
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417 | */ |
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418 | void *trace_get_payload_from_mpls(void *ethernet, uint16_t *type, |
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419 | uint32_t *remaining) { |
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420 | /* Ensure supplied type is not NULL */ |
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421 | if (!type) { |
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422 | fprintf(stderr, "NULL type passed into trace_get_payload_from_mpls()\n"); |
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423 | return NULL; |
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424 | } |
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425 | |
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426 | if ((((char*)ethernet)[2]&0x01)==0) { |
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427 | /* The MPLS Stack bit is set */ |
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428 | *type = TRACE_ETHERTYPE_MPLS; |
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429 | } |
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430 | else { |
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431 | if (!remaining || *remaining>=5) { |
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432 | switch (((char*)ethernet)[4]&0xF0) { |
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433 | case 0x40: /* IPv4 */ |
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434 | *type = TRACE_ETHERTYPE_IP; |
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435 | break; |
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436 | case 0x60: /* IPv6 */ |
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437 | *type = TRACE_ETHERTYPE_IPV6; |
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438 | break; |
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439 | default: /* VPLS */ |
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440 | /* Ethernet */ |
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441 | *type = 0; |
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442 | } |
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443 | } |
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444 | } |
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445 | ethernet=(char*)ethernet+4; |
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446 | if (remaining) { |
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447 | if (*remaining<4) |
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448 | return NULL; |
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449 | else |
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450 | *remaining-=4; |
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451 | } |
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452 | |
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453 | |
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454 | return ethernet; |
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455 | } |
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456 | |
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457 | static void *trace_get_payload_from_llcsnap(void *link, |
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458 | uint16_t *type, uint32_t *remaining) |
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459 | { |
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460 | /* 64 byte capture. */ |
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461 | libtrace_llcsnap_t *llc = (libtrace_llcsnap_t*)link; |
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462 | |
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463 | if (remaining) { |
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464 | if (*remaining < sizeof(libtrace_llcsnap_t)) { |
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465 | *remaining = 0; |
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466 | return NULL; |
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467 | } |
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468 | *remaining-=(sizeof(libtrace_llcsnap_t)); |
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469 | } |
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470 | |
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471 | llc = (libtrace_llcsnap_t*)((char *)llc); |
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472 | |
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473 | if (type) *type = ntohs(llc->type); |
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474 | |
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475 | return (void*)((char*)llc+sizeof(*llc)); |
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476 | } |
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477 | |
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478 | |
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479 | static void *trace_get_payload_from_80211(void *link, uint16_t *type, uint32_t *remaining) |
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480 | { |
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481 | libtrace_80211_t *wifi; |
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482 | uint16_t *eth; /* ethertype */ |
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483 | int8_t extra = 0; /* how many QoS bytes to skip */ |
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484 | |
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485 | if (remaining && *remaining < sizeof(libtrace_80211_t)) { |
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486 | *remaining = 0; |
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487 | return NULL; |
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488 | } |
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489 | |
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490 | wifi=(libtrace_80211_t*)link; |
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491 | |
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492 | /* Data packet? */ |
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493 | if (wifi->type != 2) { |
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494 | return NULL; |
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495 | } |
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496 | |
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497 | /* If FromDS and ToDS are both set then we have a four-address |
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498 | * frame. Otherwise we have a three-address frame */ |
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499 | if (!(wifi->to_ds && wifi->from_ds)) |
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500 | extra -= 6; |
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501 | |
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502 | /* Indicates QoS field present, see IEEE802.11e-2005 pg 21 */ |
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503 | if (wifi->subtype & 0x8) |
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504 | extra += 2; |
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505 | |
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506 | if (remaining && *remaining < sizeof(*eth)) { |
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507 | *remaining = 0; |
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508 | return NULL; |
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509 | } |
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510 | |
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511 | eth=(uint16_t *)((char*)wifi+sizeof(*wifi)+extra); |
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512 | |
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513 | if (*eth == 0xaaaa) |
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514 | /* Payload contains an 802.2 LLC/SNAP frame */ |
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515 | return trace_get_payload_from_llcsnap((void *)eth, type, remaining); |
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516 | |
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517 | /* Otherwise we assume an Ethernet II frame */ |
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518 | if (type) *type=ntohs(*eth); |
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519 | if (remaining) *remaining = *remaining - sizeof(libtrace_80211_t) - extra - sizeof(*eth); |
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520 | |
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521 | return (void*)((char*)eth+sizeof(*eth)); |
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522 | } |
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523 | |
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524 | static void *trace_get_payload_from_ppp(void *link, |
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525 | uint16_t *type, uint32_t *remaining) |
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526 | { |
---|
527 | /* 64 byte capture. */ |
---|
528 | libtrace_ppp_t *ppp = (libtrace_ppp_t*)link; |
---|
529 | |
---|
530 | if (remaining) { |
---|
531 | if (*remaining < sizeof(libtrace_ppp_t)) { |
---|
532 | *remaining = 0; |
---|
533 | return NULL; |
---|
534 | } |
---|
535 | *remaining-=sizeof(libtrace_ppp_t); |
---|
536 | } |
---|
537 | |
---|
538 | if (type) { |
---|
539 | switch(ntohs(ppp->protocol)) { |
---|
540 | case 0x0021: *type = TRACE_ETHERTYPE_IP; break; |
---|
541 | case 0x0057: *type = TRACE_ETHERTYPE_IPV6; break; |
---|
542 | /* If it isn't IP, then it is probably PPP control and |
---|
543 | * I can't imagine anyone caring about that too much |
---|
544 | */ |
---|
545 | default: *type = 0; break; |
---|
546 | } |
---|
547 | } |
---|
548 | |
---|
549 | |
---|
550 | return (void*)((char *)ppp+sizeof(*ppp)); |
---|
551 | } |
---|
552 | |
---|
553 | void *trace_get_payload_from_pppoe(void *link, uint16_t *type, |
---|
554 | uint32_t *remaining) { |
---|
555 | /* Ensure type supplied is not NULL */ |
---|
556 | if (!type) { |
---|
557 | fprintf(stderr, "NULL type passed into trace_get_payload_from_pppoe()\n"); |
---|
558 | return NULL; |
---|
559 | } |
---|
560 | |
---|
561 | if (remaining) { |
---|
562 | if (*remaining < sizeof(libtrace_pppoe_t)) { |
---|
563 | *remaining = 0; |
---|
564 | return NULL; |
---|
565 | } |
---|
566 | *remaining -= sizeof(libtrace_pppoe_t); |
---|
567 | } |
---|
568 | |
---|
569 | /* PPPoE is always followed by PPP */ |
---|
570 | return trace_get_payload_from_ppp(link + sizeof(libtrace_pppoe_t), |
---|
571 | type, remaining); |
---|
572 | } |
---|
573 | |
---|
574 | /* Header for CHDLC framing */ |
---|
575 | typedef struct libtrace_chdlc_t { |
---|
576 | uint8_t address; /** 0xF0 for unicast, 0xF8 for multicast */ |
---|
577 | uint8_t control; /** Always 0x00 */ |
---|
578 | uint16_t ethertype; |
---|
579 | } libtrace_chdlc_t; |
---|
580 | |
---|
581 | /* Header for PPP in HDLC-like framing */ |
---|
582 | typedef struct libtrace_ppp_hdlc_t { |
---|
583 | uint8_t address; /** Always should be 0xff */ |
---|
584 | uint8_t control; /** Always should be 0x03 */ |
---|
585 | uint16_t protocol; |
---|
586 | } libtrace_ppp_hdlc_t; |
---|
587 | |
---|
588 | static void *trace_get_payload_from_chdlc(void *link, uint16_t *type, |
---|
589 | uint32_t *remaining) { |
---|
590 | |
---|
591 | libtrace_chdlc_t *chdlc = (libtrace_chdlc_t *)link; |
---|
592 | |
---|
593 | if (remaining) { |
---|
594 | if (*remaining < sizeof(libtrace_chdlc_t)) { |
---|
595 | *remaining = 0; |
---|
596 | return NULL; |
---|
597 | } |
---|
598 | *remaining -= sizeof(libtrace_chdlc_t); |
---|
599 | } |
---|
600 | |
---|
601 | if (type) { |
---|
602 | *type = ntohs(chdlc->ethertype); |
---|
603 | } |
---|
604 | |
---|
605 | return (void *)((char *)chdlc + sizeof(*chdlc)); |
---|
606 | |
---|
607 | } |
---|
608 | |
---|
609 | static void *trace_get_payload_from_ppp_hdlc(void *link, |
---|
610 | uint16_t *type, uint32_t *remaining) |
---|
611 | { |
---|
612 | libtrace_ppp_hdlc_t *ppp_hdlc = (libtrace_ppp_hdlc_t*)link; |
---|
613 | |
---|
614 | if (remaining) { |
---|
615 | if (*remaining < sizeof(libtrace_ppp_hdlc_t)) { |
---|
616 | *remaining = 0; |
---|
617 | return NULL; |
---|
618 | } |
---|
619 | *remaining-=sizeof(libtrace_ppp_hdlc_t); |
---|
620 | } |
---|
621 | |
---|
622 | if (type) { |
---|
623 | /* http://www.iana.org/assignments/ppp-numbers */ |
---|
624 | |
---|
625 | switch(ntohs(ppp_hdlc->protocol)) { |
---|
626 | case 0x0021: /* IP */ |
---|
627 | *type = TRACE_ETHERTYPE_IP; |
---|
628 | break; |
---|
629 | case 0x0057: /* IPV6 */ |
---|
630 | *type = TRACE_ETHERTYPE_IPV6; |
---|
631 | break; |
---|
632 | case 0xc021: /* Link Control Protocol */ |
---|
633 | *type = 0; /* No ethertype for this */ |
---|
634 | break; |
---|
635 | |
---|
636 | default: |
---|
637 | printf("Unknown chdlc type: %04x\n", |
---|
638 | ntohs(ppp_hdlc->protocol)); |
---|
639 | *type = 0; /* Unknown */ |
---|
640 | } |
---|
641 | } |
---|
642 | |
---|
643 | |
---|
644 | return (void*)((char *)ppp_hdlc+sizeof(*ppp_hdlc)); |
---|
645 | } |
---|
646 | |
---|
647 | void *trace_get_payload_from_link(void *link, libtrace_linktype_t linktype, |
---|
648 | uint16_t *ethertype, uint32_t *remaining) |
---|
649 | { |
---|
650 | void *l = NULL; |
---|
651 | |
---|
652 | do { |
---|
653 | l = trace_get_payload_from_meta(link, &linktype, remaining); |
---|
654 | if (l != NULL) { |
---|
655 | link=l; |
---|
656 | } |
---|
657 | } while (l != NULL); |
---|
658 | |
---|
659 | return trace_get_payload_from_layer2(link,linktype,ethertype,remaining); |
---|
660 | |
---|
661 | } |
---|
662 | |
---|
663 | DLLEXPORT void *trace_get_layer2(const libtrace_packet_t *packet, |
---|
664 | libtrace_linktype_t *linktype, |
---|
665 | uint32_t *remaining) |
---|
666 | { |
---|
667 | uint32_t dummyrem; |
---|
668 | void *meta = NULL; |
---|
669 | |
---|
670 | if (!packet) { |
---|
671 | fprintf(stderr, "NULL packet passed into trace_get_layer2()\n"); |
---|
672 | return NULL; |
---|
673 | } |
---|
674 | if (!linktype) { |
---|
675 | fprintf(stderr, "NULL linktype passed into trace_get_layer2()\n"); |
---|
676 | return NULL; |
---|
677 | } |
---|
678 | |
---|
679 | if (remaining == NULL) |
---|
680 | remaining = &dummyrem; |
---|
681 | |
---|
682 | if (packet->cached.l2_header) { |
---|
683 | /* Use cached values */ |
---|
684 | *linktype = packet->cached.link_type; |
---|
685 | *remaining = packet->cached.l2_remaining; |
---|
686 | return packet->cached.l2_header; |
---|
687 | } |
---|
688 | |
---|
689 | /* Code looks a bit inefficient, but I'm actually trying to avoid |
---|
690 | * calling trace_get_packet_buffer more than once like we used to. |
---|
691 | */ |
---|
692 | meta = trace_get_packet_buffer(packet, linktype, remaining); |
---|
693 | if (meta == NULL) { |
---|
694 | return NULL; |
---|
695 | } |
---|
696 | |
---|
697 | /* If there are no meta-data headers, we just return the start of the |
---|
698 | * packet buffer, along with the linktype, etc. |
---|
699 | */ |
---|
700 | switch(*linktype) { |
---|
701 | /* meta points to a layer 2 header! */ |
---|
702 | case TRACE_TYPE_HDLC_POS: |
---|
703 | case TRACE_TYPE_ETH: |
---|
704 | case TRACE_TYPE_ATM: |
---|
705 | case TRACE_TYPE_80211: |
---|
706 | case TRACE_TYPE_NONE: |
---|
707 | case TRACE_TYPE_POS: |
---|
708 | case TRACE_TYPE_AAL5: |
---|
709 | case TRACE_TYPE_DUCK: |
---|
710 | case TRACE_TYPE_LLCSNAP: |
---|
711 | case TRACE_TYPE_PPP: |
---|
712 | case TRACE_TYPE_METADATA: |
---|
713 | case TRACE_TYPE_NONDATA: |
---|
714 | case TRACE_TYPE_OPENBSD_LOOP: |
---|
715 | ((libtrace_packet_t*)packet)->cached.l2_header = meta; |
---|
716 | ((libtrace_packet_t*)packet)->cached.l2_remaining = *remaining; |
---|
717 | return meta; |
---|
718 | case TRACE_TYPE_LINUX_SLL: |
---|
719 | case TRACE_TYPE_80211_RADIO: |
---|
720 | case TRACE_TYPE_80211_PRISM: |
---|
721 | case TRACE_TYPE_PFLOG: |
---|
722 | case TRACE_TYPE_ERF_META: |
---|
723 | case TRACE_TYPE_PCAPNG_META: |
---|
724 | case TRACE_TYPE_ETSILI: |
---|
725 | break; |
---|
726 | case TRACE_TYPE_UNKNOWN: |
---|
727 | case TRACE_TYPE_CONTENT_INVALID: |
---|
728 | return NULL; |
---|
729 | } |
---|
730 | |
---|
731 | /* If there are meta-data headers, we need to skip over them until we |
---|
732 | * find a non-meta data header and return that. |
---|
733 | */ |
---|
734 | for(;;) { |
---|
735 | void *nexthdr = trace_get_payload_from_meta(meta, |
---|
736 | linktype, remaining); |
---|
737 | |
---|
738 | if (nexthdr == NULL) { |
---|
739 | switch (*linktype) { |
---|
740 | /* meta points to a layer 2 header! */ |
---|
741 | case TRACE_TYPE_HDLC_POS: |
---|
742 | case TRACE_TYPE_ETH: |
---|
743 | case TRACE_TYPE_ATM: |
---|
744 | case TRACE_TYPE_80211: |
---|
745 | case TRACE_TYPE_NONE: |
---|
746 | case TRACE_TYPE_POS: |
---|
747 | case TRACE_TYPE_AAL5: |
---|
748 | case TRACE_TYPE_DUCK: |
---|
749 | case TRACE_TYPE_LLCSNAP: |
---|
750 | case TRACE_TYPE_PPP: |
---|
751 | case TRACE_TYPE_METADATA: |
---|
752 | case TRACE_TYPE_NONDATA: |
---|
753 | case TRACE_TYPE_OPENBSD_LOOP: |
---|
754 | ((libtrace_packet_t*)packet)->cached.l2_header = meta; |
---|
755 | ((libtrace_packet_t*)packet)->cached.l2_remaining = *remaining; |
---|
756 | return meta; |
---|
757 | case TRACE_TYPE_LINUX_SLL: |
---|
758 | case TRACE_TYPE_80211_RADIO: |
---|
759 | case TRACE_TYPE_80211_PRISM: |
---|
760 | case TRACE_TYPE_PFLOG: |
---|
761 | case TRACE_TYPE_ERF_META: |
---|
762 | case TRACE_TYPE_PCAPNG_META: |
---|
763 | case TRACE_TYPE_ETSILI: |
---|
764 | break; |
---|
765 | case TRACE_TYPE_UNKNOWN: |
---|
766 | case TRACE_TYPE_CONTENT_INVALID: |
---|
767 | return NULL; |
---|
768 | } |
---|
769 | |
---|
770 | /* Otherwise, we must have hit the end of the packet */ |
---|
771 | return NULL; |
---|
772 | } |
---|
773 | |
---|
774 | |
---|
775 | meta = nexthdr; |
---|
776 | } |
---|
777 | |
---|
778 | } |
---|
779 | |
---|
780 | DLLEXPORT |
---|
781 | void *trace_get_payload_from_atm(void *link, |
---|
782 | uint8_t *type, uint32_t *remaining) |
---|
783 | { |
---|
784 | libtrace_atm_capture_cell_t *cell; |
---|
785 | if (remaining && *remaining<sizeof(libtrace_atm_capture_cell_t)) { |
---|
786 | *remaining = 0; |
---|
787 | return NULL; |
---|
788 | } |
---|
789 | cell=(libtrace_atm_capture_cell_t*)link; |
---|
790 | |
---|
791 | if (type) |
---|
792 | *type=cell->pt; |
---|
793 | |
---|
794 | if (remaining) |
---|
795 | *remaining-=sizeof(libtrace_atm_capture_cell_t); |
---|
796 | |
---|
797 | return ((char*)link)+sizeof(libtrace_atm_capture_cell_t); |
---|
798 | } |
---|
799 | |
---|
800 | |
---|
801 | |
---|
802 | DLLEXPORT void *trace_get_payload_from_layer2(void *link, |
---|
803 | libtrace_linktype_t linktype, |
---|
804 | uint16_t *ethertype, |
---|
805 | uint32_t *remaining) |
---|
806 | { |
---|
807 | void *l; |
---|
808 | |
---|
809 | if (linktype == TRACE_TYPE_UNKNOWN || |
---|
810 | linktype == TRACE_TYPE_CONTENT_INVALID) { |
---|
811 | fprintf(stderr, "Unable to determine linktype for packet\n"); |
---|
812 | return NULL; |
---|
813 | } |
---|
814 | |
---|
815 | if (link == NULL) { |
---|
816 | return NULL; |
---|
817 | } |
---|
818 | |
---|
819 | switch(linktype) { |
---|
820 | /* Packet Metadata headers, not layer2 headers */ |
---|
821 | case TRACE_TYPE_80211_PRISM: |
---|
822 | case TRACE_TYPE_80211_RADIO: |
---|
823 | case TRACE_TYPE_PFLOG: |
---|
824 | case TRACE_TYPE_LINUX_SLL: |
---|
825 | case TRACE_TYPE_ETSILI: |
---|
826 | return NULL; |
---|
827 | |
---|
828 | /* duck packets have no payload! */ |
---|
829 | case TRACE_TYPE_DUCK: |
---|
830 | return NULL; |
---|
831 | |
---|
832 | /* The payload is in these packets does |
---|
833 | not correspond to a genuine link-layer |
---|
834 | */ |
---|
835 | case TRACE_TYPE_METADATA: |
---|
836 | case TRACE_TYPE_NONDATA: |
---|
837 | case TRACE_TYPE_PCAPNG_META: |
---|
838 | case TRACE_TYPE_ERF_META: |
---|
839 | case TRACE_TYPE_CONTENT_INVALID: |
---|
840 | case TRACE_TYPE_UNKNOWN: |
---|
841 | return NULL; |
---|
842 | |
---|
843 | case TRACE_TYPE_80211: |
---|
844 | return trace_get_payload_from_80211(link,ethertype,remaining); |
---|
845 | case TRACE_TYPE_ETH: |
---|
846 | return trace_get_payload_from_ethernet(link,ethertype,remaining); |
---|
847 | case TRACE_TYPE_NONE: |
---|
848 | if (*remaining == 0) { |
---|
849 | return NULL; |
---|
850 | } |
---|
851 | |
---|
852 | if ((*(char*)link&0xF0) == 0x40) |
---|
853 | *ethertype=TRACE_ETHERTYPE_IP; /* IPv4 */ |
---|
854 | else if ((*(char*)link&0xF0) == 0x60) |
---|
855 | *ethertype=TRACE_ETHERTYPE_IPV6; /* IPv6 */ |
---|
856 | else |
---|
857 | return NULL; /* No idea */ |
---|
858 | return link; /* I love the simplicity */ |
---|
859 | case TRACE_TYPE_PPP: |
---|
860 | return trace_get_payload_from_ppp(link,ethertype,remaining); |
---|
861 | case TRACE_TYPE_ATM: |
---|
862 | l=trace_get_payload_from_atm(link,NULL,remaining); |
---|
863 | /* FIXME: We shouldn't skip llcsnap here, we should |
---|
864 | * return an ethertype for it (somehow) |
---|
865 | */ |
---|
866 | return (l ? trace_get_payload_from_llcsnap(l, |
---|
867 | ethertype, remaining):NULL); |
---|
868 | case TRACE_TYPE_LLCSNAP: |
---|
869 | return trace_get_payload_from_llcsnap(link,ethertype,remaining); |
---|
870 | |
---|
871 | case TRACE_TYPE_HDLC_POS: |
---|
872 | return trace_get_payload_from_chdlc(link,ethertype, |
---|
873 | remaining); |
---|
874 | case TRACE_TYPE_POS: |
---|
875 | return trace_get_payload_from_ppp_hdlc(link,ethertype, |
---|
876 | remaining); |
---|
877 | /* TODO: Unsupported */ |
---|
878 | case TRACE_TYPE_AAL5: |
---|
879 | return NULL; |
---|
880 | |
---|
881 | case TRACE_TYPE_OPENBSD_LOOP: |
---|
882 | if (*remaining <= 4) { |
---|
883 | return NULL; |
---|
884 | } |
---|
885 | link = link + 4; /* Loopback header is 4 bytes */ |
---|
886 | if ((*(char*)link&0xF0) == 0x40) |
---|
887 | *ethertype=TRACE_ETHERTYPE_IP; /* IPv4 */ |
---|
888 | else if ((*(char*)link&0xF0) == 0x60) |
---|
889 | *ethertype=TRACE_ETHERTYPE_IPV6; /* IPv6 */ |
---|
890 | else |
---|
891 | return NULL; |
---|
892 | return link; /* I love the simplicity */ |
---|
893 | |
---|
894 | |
---|
895 | } |
---|
896 | return NULL; |
---|
897 | |
---|
898 | } |
---|
899 | |
---|
900 | /* Take a pointer to the start of an IEEE 802.11 MAC frame and return a pointer |
---|
901 | * to the source MAC address. |
---|
902 | * If the frame does not contain a sender address, e.g. ACK frame, return NULL. |
---|
903 | * If the frame is a 4-address WDS frame, return TA, i.e. addr2. |
---|
904 | * NB: This function decodes the 802.11 header, so it assumes that there are no |
---|
905 | * bit-errors. If there are, all bets are off. |
---|
906 | */ |
---|
907 | static |
---|
908 | uint8_t *get_source_mac_from_wifi(void *wifi) { |
---|
909 | struct libtrace_80211_t *w; |
---|
910 | if (wifi == NULL) return NULL; |
---|
911 | w = (struct libtrace_80211_t *) wifi; |
---|
912 | |
---|
913 | /* If the frame is of type CTRL */ |
---|
914 | if (w->type == 0x1) |
---|
915 | /* If bit 2 of the subtype field is zero, this indicates that |
---|
916 | * there is no transmitter address, i.e. the frame is either an |
---|
917 | * ACK or a CTS frame */ |
---|
918 | if ((w->subtype & 0x2) == 0) |
---|
919 | return NULL; |
---|
920 | |
---|
921 | /* Always return the address of the transmitter, i.e. address 2 */ |
---|
922 | return (uint8_t *) &w->mac2; |
---|
923 | } |
---|
924 | |
---|
925 | DLLEXPORT uint8_t *trace_get_source_mac(libtrace_packet_t *packet) { |
---|
926 | /* Ensure the supplied packet is not NULL */ |
---|
927 | if (!packet) { |
---|
928 | fprintf(stderr, "NULL packet passed into trace_get_source_mac()\n"); |
---|
929 | return NULL; |
---|
930 | } |
---|
931 | |
---|
932 | void *link; |
---|
933 | uint32_t remaining; |
---|
934 | libtrace_linktype_t linktype; |
---|
935 | link = trace_get_layer2(packet,&linktype,&remaining); |
---|
936 | |
---|
937 | if (!link) |
---|
938 | return NULL; |
---|
939 | |
---|
940 | switch (linktype) { |
---|
941 | case TRACE_TYPE_ETH: |
---|
942 | return (uint8_t *)&(((libtrace_ether_t*)link)->ether_shost); |
---|
943 | case TRACE_TYPE_80211: |
---|
944 | return get_source_mac_from_wifi(link); |
---|
945 | /* These packets don't have MAC addresses */ |
---|
946 | case TRACE_TYPE_POS: |
---|
947 | case TRACE_TYPE_NONE: |
---|
948 | case TRACE_TYPE_HDLC_POS: |
---|
949 | case TRACE_TYPE_PFLOG: |
---|
950 | case TRACE_TYPE_ATM: |
---|
951 | case TRACE_TYPE_DUCK: |
---|
952 | case TRACE_TYPE_METADATA: |
---|
953 | case TRACE_TYPE_AAL5: |
---|
954 | case TRACE_TYPE_LLCSNAP: |
---|
955 | case TRACE_TYPE_PPP: |
---|
956 | case TRACE_TYPE_NONDATA: |
---|
957 | case TRACE_TYPE_OPENBSD_LOOP: |
---|
958 | case TRACE_TYPE_ERF_META: |
---|
959 | case TRACE_TYPE_PCAPNG_META: |
---|
960 | case TRACE_TYPE_UNKNOWN: |
---|
961 | case TRACE_TYPE_CONTENT_INVALID: |
---|
962 | return NULL; |
---|
963 | |
---|
964 | /* Metadata headers should already be skipped */ |
---|
965 | case TRACE_TYPE_LINUX_SLL: |
---|
966 | case TRACE_TYPE_80211_PRISM: |
---|
967 | case TRACE_TYPE_80211_RADIO: |
---|
968 | case TRACE_TYPE_ETSILI: |
---|
969 | fprintf(stderr, "Metadata headers should already be skipped in trace_get_source_mac()\n"); |
---|
970 | return NULL; |
---|
971 | } |
---|
972 | fprintf(stderr,"%s not implemented for linktype %i\n", __func__, linktype); |
---|
973 | return NULL; |
---|
974 | } |
---|
975 | |
---|
976 | DLLEXPORT uint8_t *trace_get_destination_mac(libtrace_packet_t *packet) { |
---|
977 | /* Ensure the supplied packet is not NULL */ |
---|
978 | if (!packet) { |
---|
979 | fprintf(stderr, "NULL packet passed into trace_get_destination_mac()\n"); |
---|
980 | return NULL; |
---|
981 | } |
---|
982 | |
---|
983 | void *link; |
---|
984 | libtrace_linktype_t linktype; |
---|
985 | uint32_t remaining; |
---|
986 | libtrace_80211_t *wifi; |
---|
987 | libtrace_ether_t *ethptr; |
---|
988 | |
---|
989 | link = trace_get_layer2(packet,&linktype,&remaining); |
---|
990 | |
---|
991 | ethptr = (libtrace_ether_t*)link; |
---|
992 | |
---|
993 | |
---|
994 | if (!link) |
---|
995 | return NULL; |
---|
996 | |
---|
997 | switch (linktype) { |
---|
998 | case TRACE_TYPE_80211: |
---|
999 | wifi=(libtrace_80211_t*)link; |
---|
1000 | return (uint8_t*)&wifi->mac1; |
---|
1001 | case TRACE_TYPE_ETH: |
---|
1002 | return (uint8_t*)ðptr->ether_dhost; |
---|
1003 | case TRACE_TYPE_POS: |
---|
1004 | case TRACE_TYPE_NONE: |
---|
1005 | case TRACE_TYPE_ATM: |
---|
1006 | case TRACE_TYPE_HDLC_POS: |
---|
1007 | case TRACE_TYPE_PFLOG: |
---|
1008 | case TRACE_TYPE_DUCK: |
---|
1009 | case TRACE_TYPE_METADATA: |
---|
1010 | case TRACE_TYPE_AAL5: |
---|
1011 | case TRACE_TYPE_LLCSNAP: |
---|
1012 | case TRACE_TYPE_PPP: |
---|
1013 | case TRACE_TYPE_NONDATA: |
---|
1014 | case TRACE_TYPE_OPENBSD_LOOP: |
---|
1015 | case TRACE_TYPE_ERF_META: |
---|
1016 | case TRACE_TYPE_PCAPNG_META: |
---|
1017 | case TRACE_TYPE_UNKNOWN: |
---|
1018 | case TRACE_TYPE_CONTENT_INVALID: |
---|
1019 | /* No MAC address */ |
---|
1020 | return NULL; |
---|
1021 | /* Metadata headers should already be skipped */ |
---|
1022 | case TRACE_TYPE_LINUX_SLL: |
---|
1023 | case TRACE_TYPE_80211_PRISM: |
---|
1024 | case TRACE_TYPE_80211_RADIO: |
---|
1025 | case TRACE_TYPE_ETSILI: |
---|
1026 | fprintf(stderr, "Metadata headers should already be skipped in trace_get_destination_mac()\n"); |
---|
1027 | return NULL; |
---|
1028 | } |
---|
1029 | fprintf(stderr,"Not implemented\n"); |
---|
1030 | return NULL; |
---|
1031 | } |
---|
1032 | |
---|