1 | /* Protocol decodes for packet metadata headers */ |
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2 | #include "libtrace.h" |
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3 | #include "libtrace_int.h" |
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4 | #include "protocols.h" |
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5 | #include <assert.h> |
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6 | |
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7 | #ifndef WIN32 |
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8 | #include <net/if_arp.h> |
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9 | #endif |
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10 | |
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11 | #ifndef ARPHRD_ETHER |
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12 | #define ARPHRD_ETHER 1 /* Ethernet 10/100Mbps. */ |
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13 | #endif |
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14 | |
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15 | #ifndef ARPHRD_PPP |
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16 | #define ARPHRD_PPP 512 |
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17 | #endif |
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18 | |
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19 | /* NB: type is returned as an ARPHRD_ type for SLL*/ |
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20 | void *trace_get_payload_from_linux_sll(const void *link, |
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21 | uint16_t *type, uint32_t *remaining) |
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22 | { |
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23 | libtrace_sll_header_t *sll; |
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24 | |
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25 | sll = (libtrace_sll_header_t*) link; |
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26 | |
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27 | if (remaining) { |
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28 | if (*remaining <= sizeof(*sll)) |
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29 | return NULL; |
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30 | *remaining-=sizeof(*sll); |
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31 | } |
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32 | |
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33 | if (type) *type = ntohs(sll->hatype); |
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34 | |
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35 | return (void*)((char*)sll+sizeof(*sll)); |
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36 | |
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37 | } |
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38 | |
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39 | /* NB: type is returned as an ethertype */ |
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40 | static void *trace_get_payload_from_pflog(const void *link, |
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41 | libtrace_linktype_t *type, uint32_t *remaining) |
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42 | { |
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43 | libtrace_pflog_header_t *pflog = (libtrace_pflog_header_t*)link; |
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44 | if (remaining) { |
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45 | if (*remaining<=sizeof(*pflog)) |
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46 | return NULL; |
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47 | *remaining-=sizeof(*pflog); |
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48 | } |
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49 | if (type) { |
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50 | *type = TRACE_TYPE_NONE; |
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51 | } |
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52 | return (void*)((char*)pflog+ sizeof(*pflog)); |
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53 | } |
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54 | |
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55 | /* Returns the 'payload' of the prism header, which is the 802.11 frame */ |
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56 | static void *trace_get_payload_from_prism (const void *link, |
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57 | libtrace_linktype_t *type, uint32_t *remaining) |
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58 | { |
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59 | if (remaining) { |
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60 | if (*remaining<=144) |
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61 | return NULL; |
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62 | *remaining-=144; |
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63 | } |
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64 | |
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65 | if (type) *type = TRACE_TYPE_80211; |
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66 | |
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67 | return (void *) ((char*)link+144); |
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68 | } |
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69 | |
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70 | /* Returns the 'payload' of the radiotap header, which is the 802.11 frame */ |
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71 | static void *trace_get_payload_from_radiotap (const void *link, |
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72 | libtrace_linktype_t *type, uint32_t *remaining) |
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73 | { |
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74 | struct libtrace_radiotap_t *rtap = (struct libtrace_radiotap_t*)link; |
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75 | uint16_t rtaplen = bswap_le_to_host16(rtap->it_len); |
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76 | if (remaining) { |
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77 | if (*remaining <= rtaplen) |
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78 | return NULL; |
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79 | *remaining -= rtaplen; |
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80 | } |
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81 | |
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82 | if (type) *type = TRACE_TYPE_80211; |
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83 | |
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84 | return (void*) ((char*)link + rtaplen); |
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85 | } |
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86 | |
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87 | DLLEXPORT void *trace_get_packet_meta(const libtrace_packet_t *packet, |
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88 | libtrace_linktype_t *linktype, |
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89 | uint32_t *remaining) |
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90 | { |
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91 | uint32_t dummyrem; |
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92 | |
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93 | assert(packet != NULL); |
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94 | assert(linktype != NULL); |
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95 | |
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96 | if (remaining == NULL) |
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97 | remaining = &dummyrem; |
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98 | |
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99 | void *pktbuf = trace_get_packet_buffer(packet, linktype, remaining); |
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100 | switch (*linktype) { |
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101 | case TRACE_TYPE_LINUX_SLL: |
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102 | case TRACE_TYPE_80211_RADIO: |
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103 | case TRACE_TYPE_80211_PRISM: |
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104 | return pktbuf; |
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105 | /* Non metadata packets */ |
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106 | case TRACE_TYPE_HDLC_POS: |
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107 | case TRACE_TYPE_ETH: |
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108 | case TRACE_TYPE_ATM: |
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109 | case TRACE_TYPE_80211: |
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110 | case TRACE_TYPE_NONE: |
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111 | case TRACE_TYPE_PFLOG: |
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112 | case TRACE_TYPE_POS: |
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113 | case TRACE_TYPE_AAL5: |
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114 | case TRACE_TYPE_DUCK: |
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115 | case TRACE_TYPE_LLCSNAP: |
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116 | case TRACE_TYPE_PPP: |
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117 | case TRACE_TYPE_METADATA: |
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118 | return NULL; |
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119 | } |
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120 | |
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121 | /* Shouldn't get here */ |
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122 | return NULL; |
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123 | } |
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124 | |
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125 | DLLEXPORT void *trace_get_payload_from_meta(const void *meta, |
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126 | libtrace_linktype_t *linktype, |
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127 | uint32_t *remaining) |
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128 | { |
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129 | void *nexthdr; |
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130 | uint16_t arphrd; |
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131 | |
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132 | assert(meta != NULL); |
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133 | assert(linktype != NULL); |
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134 | assert(remaining != NULL); |
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135 | |
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136 | switch(*linktype) { |
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137 | case TRACE_TYPE_LINUX_SLL: |
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138 | nexthdr = trace_get_payload_from_linux_sll(meta, |
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139 | &arphrd, remaining); |
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140 | *linktype = arphrd_type_to_libtrace(arphrd); |
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141 | return nexthdr; |
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142 | case TRACE_TYPE_80211_RADIO: |
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143 | nexthdr = trace_get_payload_from_radiotap(meta, |
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144 | linktype, remaining); |
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145 | return nexthdr; |
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146 | case TRACE_TYPE_80211_PRISM: |
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147 | nexthdr = trace_get_payload_from_prism(meta, |
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148 | linktype, remaining); |
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149 | return nexthdr; |
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150 | case TRACE_TYPE_PFLOG: |
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151 | nexthdr = trace_get_payload_from_pflog(meta, |
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152 | linktype, remaining); |
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153 | return nexthdr; |
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154 | case TRACE_TYPE_HDLC_POS: |
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155 | case TRACE_TYPE_ETH: |
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156 | case TRACE_TYPE_ATM: |
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157 | case TRACE_TYPE_80211: |
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158 | case TRACE_TYPE_NONE: |
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159 | case TRACE_TYPE_POS: |
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160 | case TRACE_TYPE_AAL5: |
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161 | case TRACE_TYPE_DUCK: |
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162 | case TRACE_TYPE_LLCSNAP: |
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163 | case TRACE_TYPE_PPP: |
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164 | case TRACE_TYPE_METADATA: |
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165 | /* In this case, the pointer passed in does not point |
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166 | * to a metadata header and so we cannot get the |
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167 | * payload. |
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168 | */ |
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169 | return NULL; |
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170 | } |
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171 | /* Shouldn't get here */ |
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172 | return NULL; |
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173 | } |
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174 | |
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175 | /* Take a pointer to the start of an IEEE 802.11 MAC frame and return a pointer |
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176 | * to the source MAC address. |
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177 | * If the frame does not contain a sender address, e.g. ACK frame, return NULL. |
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178 | * If the frame is a 4-address WDS frame, return TA, i.e. addr2. |
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179 | * NB: This function decodes the 802.11 header, so it assumes that there are no |
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180 | * bit-errors. If there are, all bets are off. |
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181 | */ |
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182 | static |
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183 | uint8_t *get_source_mac_from_wifi(void *wifi) { |
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184 | if (wifi == NULL) return NULL; |
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185 | struct libtrace_80211_t *w = (struct libtrace_80211_t *) wifi; |
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186 | |
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187 | /* If the frame is of type CTRL */ |
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188 | if (w->type == 0x1) |
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189 | /* If bit 2 of the subtype field is zero, this indicates that |
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190 | * there is no transmitter address, i.e. the frame is either an |
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191 | * ACK or a CTS frame */ |
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192 | if ((w->subtype & 0x2) == 0) |
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193 | return NULL; |
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194 | |
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195 | /* Always return the address of the transmitter, i.e. address 2 */ |
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196 | return (uint8_t *) &w->mac2; |
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197 | } |
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198 | |
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199 | DLLEXPORT uint8_t *trace_get_source_mac(libtrace_packet_t *packet) { |
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200 | void *link; |
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201 | uint32_t remaining; |
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202 | libtrace_linktype_t linktype; |
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203 | assert(packet); |
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204 | link = trace_get_layer2(packet,&linktype,&remaining); |
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205 | |
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206 | if (!link) |
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207 | return NULL; |
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208 | |
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209 | switch (linktype) { |
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210 | case TRACE_TYPE_ETH: |
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211 | return (uint8_t *)&(((libtrace_ether_t*)link)->ether_shost); |
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212 | case TRACE_TYPE_80211: |
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213 | return get_source_mac_from_wifi(link); |
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214 | /* These packets don't have MAC addresses */ |
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215 | case TRACE_TYPE_POS: |
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216 | case TRACE_TYPE_NONE: |
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217 | case TRACE_TYPE_HDLC_POS: |
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218 | case TRACE_TYPE_PFLOG: |
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219 | case TRACE_TYPE_ATM: |
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220 | case TRACE_TYPE_DUCK: |
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221 | case TRACE_TYPE_METADATA: |
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222 | case TRACE_TYPE_AAL5: |
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223 | case TRACE_TYPE_LLCSNAP: |
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224 | case TRACE_TYPE_PPP: |
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225 | return NULL; |
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226 | |
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227 | /* Metadata headers should already be skipped */ |
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228 | case TRACE_TYPE_LINUX_SLL: |
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229 | case TRACE_TYPE_80211_PRISM: |
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230 | case TRACE_TYPE_80211_RADIO: |
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231 | assert(!"Metadata headers should already be skipped"); |
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232 | break; |
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233 | } |
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234 | fprintf(stderr,"%s not implemented for linktype %i\n", __func__, linktype); |
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235 | assert(0); |
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236 | return NULL; |
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237 | } |
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238 | |
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239 | DLLEXPORT uint8_t *trace_get_destination_mac(libtrace_packet_t *packet) |
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240 | { |
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241 | void *link; |
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242 | libtrace_linktype_t linktype; |
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243 | uint32_t remaining; |
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244 | |
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245 | link = trace_get_layer2(packet,&linktype,&remaining); |
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246 | |
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247 | libtrace_80211_t *wifi; |
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248 | libtrace_ether_t *ethptr = (libtrace_ether_t*)link; |
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249 | |
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250 | |
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251 | if (!link) |
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252 | return NULL; |
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253 | |
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254 | switch (linktype) { |
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255 | case TRACE_TYPE_80211: |
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256 | wifi=(libtrace_80211_t*)link; |
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257 | return (uint8_t*)&wifi->mac1; |
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258 | case TRACE_TYPE_80211_RADIO: |
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259 | wifi=(libtrace_80211_t*)trace_get_payload_from_radiotap( |
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260 | link,NULL,NULL); |
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261 | return (uint8_t*)&wifi->mac1; |
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262 | case TRACE_TYPE_80211_PRISM: |
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263 | wifi=(libtrace_80211_t*)((char*)link+144); |
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264 | return (uint8_t*)&wifi->mac1; |
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265 | case TRACE_TYPE_ETH: |
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266 | return (uint8_t*)ðptr->ether_dhost; |
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267 | case TRACE_TYPE_POS: |
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268 | case TRACE_TYPE_NONE: |
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269 | case TRACE_TYPE_ATM: |
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270 | case TRACE_TYPE_HDLC_POS: |
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271 | case TRACE_TYPE_LINUX_SLL: |
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272 | case TRACE_TYPE_PFLOG: |
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273 | case TRACE_TYPE_DUCK: |
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274 | case TRACE_TYPE_METADATA: |
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275 | /* No MAC address */ |
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276 | return NULL; |
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277 | default: |
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278 | break; |
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279 | } |
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280 | fprintf(stderr,"Not implemented\n"); |
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281 | assert(0); |
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282 | return NULL; |
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283 | } |
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284 | |
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285 | |
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