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1 | 6 | kaklik | /*! \file arp.c \brief ARP Protocol Library. */ |
2 | //***************************************************************************** |
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3 | // |
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4 | // File Name : 'arp.c' |
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5 | // Title : ARP Protocol Library |
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6 | // Author : Pascal Stang |
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7 | // Created : 9/7/2004 |
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8 | // Revised : 7/3/2005 |
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9 | // Version : 0.1 |
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10 | // Target MCU : Atmel AVR series |
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11 | // Editor Tabs : 4 |
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12 | // |
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13 | //***************************************************************************** |
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14 | |||
15 | #include "global.h" |
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16 | #include "net.h" |
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17 | #include "nic.h" |
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18 | #include "arp.h" |
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19 | |||
20 | #include "rprintf.h" |
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21 | |||
22 | // global variables |
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23 | |||
24 | /// Single ARP table entry/record |
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25 | struct ArpEntry |
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26 | { |
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27 | uint32_t ipaddr; ///< remote-note IP address |
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28 | struct netEthAddr ethaddr; ///< remote-node ethernet (hardware/mac) address |
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29 | uint8_t time; ///< time to live (in ARP table); this is decremented by arpTimer() |
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30 | }; |
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31 | |||
32 | struct ArpEntry ArpMyAddr; ///< my local interface information (IP and MAC address) |
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33 | struct ArpEntry ArpTable[ARP_TABLE_SIZE]; ///< ARP table of matched IP<->MAC associations |
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34 | |||
35 | |||
36 | void arpInit(void) |
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37 | { |
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38 | u08 i; |
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39 | // initialize all ArpTable elements to unused |
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40 | for(i=0; i<ARP_TABLE_SIZE; i++) |
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41 | { |
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42 | ArpTable[i].ipaddr = 0; |
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43 | ArpTable[i].time = 0; |
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44 | } |
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45 | } |
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46 | |||
47 | void arpSetAddress(struct netEthAddr* myeth, uint32_t myip) |
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48 | { |
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49 | // set local address record |
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50 | ArpMyAddr.ethaddr = *myeth; |
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51 | ArpMyAddr.ipaddr = myip; |
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52 | } |
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53 | |||
54 | void arpArpIn(unsigned int len, struct netEthArpHeader* packet) |
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55 | { |
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56 | #ifdef ARP_DEBUG |
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57 | rprintfProgStrM("Received ARP Request\r\n"); |
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58 | arpPrintHeader( &packet->arp ); |
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59 | #endif |
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60 | |||
61 | // for now, we just reply to requests |
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62 | // need to add ARP cache |
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63 | if( (packet->arp.dipaddr == HTONL(ArpMyAddr.ipaddr)) && |
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64 | (packet->arp.opcode == htons(ARP_OPCODE_REQUEST)) ) |
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65 | { |
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66 | // in ARP header |
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67 | // copy sender's address info to dest. fields |
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68 | packet->arp.dhwaddr = packet->arp.shwaddr; |
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69 | packet->arp.dipaddr = packet->arp.sipaddr; |
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70 | // fill in our information |
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71 | packet->arp.shwaddr = ArpMyAddr.ethaddr; |
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72 | packet->arp.sipaddr = HTONL(ArpMyAddr.ipaddr); |
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73 | // change op to reply |
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74 | packet->arp.opcode = htons(ARP_OPCODE_REPLY); |
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75 | |||
76 | // in ethernet header |
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77 | packet->eth.dest = packet->eth.src; |
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78 | packet->eth.src = ArpMyAddr.ethaddr; |
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79 | |||
80 | #ifdef ARP_DEBUG |
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81 | rprintfProgStrM("Sending ARP Reply\r\n"); |
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82 | arpPrintHeader( &packet->arp ); |
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83 | #endif |
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84 | |||
85 | // send reply! |
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86 | nicSend(len, (unsigned char*)packet); |
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87 | } |
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88 | } |
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89 | |||
90 | void arpIpIn(struct netEthIpHeader* packet) |
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91 | { |
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92 | int8_t index; |
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93 | |||
94 | // check if sender is already present in arp table |
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95 | index = arpMatchIp(HTONL(packet->ip.srcipaddr)); |
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96 | if(index != -1) |
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97 | { |
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98 | // sender's IP address found, update ARP entry |
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99 | ArpTable[index].ethaddr = packet->eth.src; |
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100 | // and we're done |
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101 | return; |
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102 | } |
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103 | |||
104 | // sender was not present in table, |
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105 | // must add in empty/expired slot |
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106 | for(index=0; index<ARP_TABLE_SIZE; index++) |
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107 | { |
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108 | if(!ArpTable[index].time) |
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109 | { |
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110 | // write entry |
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111 | ArpTable[index].ethaddr = packet->eth.src; |
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112 | ArpTable[index].ipaddr = HTONL(packet->ip.srcipaddr); |
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113 | ArpTable[index].time = ARP_CACHE_TIME_TO_LIVE; |
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114 | // and we're done |
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115 | return; |
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116 | } |
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117 | } |
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118 | |||
119 | // no space in table, we give up |
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120 | } |
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121 | |||
122 | void arpIpOut(struct netEthIpHeader* packet, uint32_t phyDstIp) |
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123 | { |
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124 | int index; |
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125 | // check if destination is already present in arp table |
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126 | // use the physical dstIp if it's provided, otherwise the dstIp in packet |
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127 | if(phyDstIp) |
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128 | index = arpMatchIp(phyDstIp); |
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129 | else |
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130 | index = arpMatchIp(HTONL(packet->ip.destipaddr)); |
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131 | // fill in ethernet info |
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132 | if(index != -1) |
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133 | { |
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134 | // ARP entry present, fill eth address(es) |
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135 | packet->eth.src = ArpMyAddr.ethaddr; |
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136 | packet->eth.dest = ArpTable[index].ethaddr; |
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137 | packet->eth.type = HTONS(ETHTYPE_IP); |
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138 | } |
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139 | else |
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140 | { |
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141 | // not in table, must send ARP request |
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142 | packet->eth.src = ArpMyAddr.ethaddr; |
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143 | // MUST CHANGE, but for now, send this one broadcast |
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144 | packet->eth.dest.addr[0] = 0xFF; |
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145 | packet->eth.dest.addr[1] = 0xFF; |
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146 | packet->eth.dest.addr[2] = 0xFF; |
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147 | packet->eth.dest.addr[3] = 0xFF; |
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148 | packet->eth.dest.addr[4] = 0xFF; |
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149 | packet->eth.dest.addr[5] = 0xFF; |
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150 | packet->eth.type = HTONS(ETHTYPE_IP); |
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151 | } |
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152 | } |
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153 | |||
154 | void arpTimer(void) |
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155 | { |
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156 | int index; |
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157 | // this function meant to be called on a regular time interval |
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158 | |||
159 | // decrement time-to-live for all entries |
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160 | for(index=0; index<ARP_TABLE_SIZE; index++) |
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161 | { |
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162 | if(ArpTable[index].time) |
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163 | ArpTable[index].time--; |
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164 | } |
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165 | } |
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166 | |||
167 | int arpMatchIp(uint32_t ipaddr) |
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168 | { |
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169 | uint8_t i; |
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170 | |||
171 | // check if IP address is present in arp table |
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172 | for(i=0; i<ARP_TABLE_SIZE; i++) |
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173 | { |
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174 | if(ArpTable[i].ipaddr == ipaddr) |
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175 | { |
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176 | // IP address found |
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177 | return i; |
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178 | } |
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179 | } |
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180 | |||
181 | // no match |
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182 | return -1; |
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183 | } |
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184 | |||
185 | #ifdef ARP_DEBUG_PRINT |
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186 | void arpPrintHeader(struct netArpHeader* packet) |
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187 | { |
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188 | rprintfProgStrM("ARP Packet:\r\n"); |
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189 | //debugPrintHexTable(60, (unsigned char*)&packet); |
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190 | // print operation type |
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191 | rprintfProgStrM("Operation : "); |
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192 | if(packet->opcode == htons(ARP_OPCODE_REQUEST)) |
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193 | rprintfProgStrM("REQUEST"); |
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194 | else if(packet->opcode == htons(ARP_OPCODE_REPLY)) |
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195 | rprintfProgStrM("REPLY"); |
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196 | else |
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197 | rprintfProgStrM("UNKNOWN"); |
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198 | rprintfCRLF(); |
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199 | // print source hardware address |
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200 | rprintfProgStrM("SrcHwAddr : "); netPrintEthAddr(&packet->shwaddr); rprintfCRLF(); |
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201 | // print source protocol address |
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202 | rprintfProgStrM("SrcProtoAddr: "); netPrintIPAddr(HTONL(packet->sipaddr)); rprintfCRLF(); |
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203 | // print target hardware address |
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204 | rprintfProgStrM("DstHwAddr : "); netPrintEthAddr(&packet->dhwaddr); rprintfCRLF(); |
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205 | // print target protocol address |
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206 | rprintfProgStrM("DstProtoAddr: "); netPrintIPAddr(HTONL(packet->dipaddr)); rprintfCRLF(); |
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207 | } |
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208 | |||
209 | |||
210 | void arpPrintTable(void) |
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211 | { |
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212 | uint8_t i; |
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213 | |||
214 | // print ARP table |
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215 | rprintfProgStrM("Time Eth Address IP Address\r\n"); |
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216 | rprintfProgStrM("---------------------------------------\r\n"); |
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217 | for(i=0; i<ARP_TABLE_SIZE; i++) |
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218 | { |
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219 | rprintfu08(ArpTable[i].time); |
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220 | rprintfProgStrM(" "); |
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221 | netPrintEthAddr(&ArpTable[i].ethaddr); |
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222 | rprintfProgStrM(" "); |
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223 | netPrintIPAddr(ArpTable[i].ipaddr); |
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224 | rprintfCRLF(); |
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225 | } |
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226 | } |
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227 | #endif |
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