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1 | 32 | kaklik | /********************************************************************* |
2 | * |
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3 | * Domain Name System (DNS) Server dummy |
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4 | * Module for Microchip TCP/IP Stack |
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5 | * -Acts as a DNS server, but gives out the local IP address for all |
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6 | * queries to force web browsers to access the board. |
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7 | * -Reference: RFC 1034 and RFC 1035 |
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8 | * |
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9 | ********************************************************************* |
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10 | * FileName: DNSs.c |
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11 | * Dependencies: UDP |
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12 | * Processor: PIC18, PIC24F, PIC24H, dsPIC30F, dsPIC33F, PIC32 |
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13 | * Compiler: Microchip C32 v1.05 or higher |
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14 | * Microchip C30 v3.12 or higher |
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15 | * Microchip C18 v3.30 or higher |
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16 | * Company: Microchip Technology, Inc. |
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17 | * |
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18 | * Software License Agreement |
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19 | * |
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20 | * Copyright (C) 2002-2010 Microchip Technology Inc. All rights |
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21 | * reserved. |
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22 | * |
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23 | * Microchip licenses to you the right to use, modify, copy, and |
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24 | * distribute: |
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25 | * (i) the Software when embedded on a Microchip microcontroller or |
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26 | * digital signal controller product ("Device") which is |
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27 | * integrated into Licensee's product; or |
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28 | * (ii) ONLY the Software driver source files ENC28J60.c, ENC28J60.h, |
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29 | * ENCX24J600.c and ENCX24J600.h ported to a non-Microchip device |
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30 | * used in conjunction with a Microchip ethernet controller for |
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31 | * the sole purpose of interfacing with the ethernet controller. |
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32 | * |
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33 | * You should refer to the license agreement accompanying this |
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34 | * Software for additional information regarding your rights and |
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35 | * obligations. |
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36 | * |
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37 | * THE SOFTWARE AND DOCUMENTATION ARE PROVIDED "AS IS" WITHOUT |
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38 | * WARRANTY OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT |
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39 | * LIMITATION, ANY WARRANTY OF MERCHANTABILITY, FITNESS FOR A |
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40 | * PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT SHALL |
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41 | * MICROCHIP BE LIABLE FOR ANY INCIDENTAL, SPECIAL, INDIRECT OR |
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42 | * CONSEQUENTIAL DAMAGES, LOST PROFITS OR LOST DATA, COST OF |
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43 | * PROCUREMENT OF SUBSTITUTE GOODS, TECHNOLOGY OR SERVICES, ANY CLAIMS |
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44 | * BY THIRD PARTIES (INCLUDING BUT NOT LIMITED TO ANY DEFENSE |
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45 | * THEREOF), ANY CLAIMS FOR INDEMNITY OR CONTRIBUTION, OR OTHER |
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46 | * SIMILAR COSTS, WHETHER ASSERTED ON THE BASIS OF CONTRACT, TORT |
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47 | * (INCLUDING NEGLIGENCE), BREACH OF WARRANTY, OR OTHERWISE. |
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48 | * |
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49 | * |
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50 | * Author Date Comment |
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51 | *~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
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52 | * Howard Schlunder 01/18/2010 Original |
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53 | ********************************************************************/ |
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54 | #define DNSS_C |
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55 | |||
56 | #include "TCPIPConfig.h" |
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57 | |||
58 | #if defined(STACK_USE_DNS_SERVER) |
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59 | |||
60 | #include "TCPIP Stack/TCPIP.h" |
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61 | |||
62 | // Default port for the DNS server to listen on |
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63 | #define DNS_PORT 53u |
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64 | |||
65 | |||
66 | static void DNSCopyRXNameToTX(void); |
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67 | |||
68 | /********************************************************************* |
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69 | * Function: void DNSServerTask(void) |
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70 | * |
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71 | * PreCondition: None |
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72 | * |
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73 | * Input: None |
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74 | * |
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75 | * Output: None |
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76 | * |
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77 | * Side Effects: None |
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78 | * |
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79 | * Overview: Sends dummy responses that point to ourself for DNS requests |
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80 | * |
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81 | * Note: None |
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82 | ********************************************************************/ |
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83 | void DNSServerTask(void) |
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84 | { |
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85 | static UDP_SOCKET MySocket = INVALID_UDP_SOCKET; |
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86 | struct |
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87 | { |
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88 | WORD wTransactionID; |
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89 | WORD wFlags; |
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90 | WORD wQuestions; |
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91 | WORD wAnswerRRs; |
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92 | WORD wAuthorityRRs; |
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93 | WORD wAdditionalRRs; |
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94 | } DNSHeader; |
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95 | |||
96 | |||
97 | // Create a socket to listen on if this is the first time calling this function |
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98 | if(MySocket == INVALID_UDP_SOCKET) |
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99 | { |
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100 | MySocket = UDPOpen(DNS_PORT, NULL, 0); |
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101 | return; |
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102 | } |
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103 | |||
104 | // See if a DNS query packet has arrived |
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105 | if(UDPIsGetReady(MySocket) < sizeof(DNSHeader)) |
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106 | return; |
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107 | |||
108 | // Read DNS header |
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109 | UDPGetArray((BYTE*)&DNSHeader, sizeof(DNSHeader)); |
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110 | |||
111 | // Ignore this packet if it isn't a query |
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112 | if((DNSHeader.wFlags & 0x8000) == 0x8000u) |
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113 | return; |
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114 | |||
115 | // Ignore this packet if there are no questions in it |
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116 | if(DNSHeader.wQuestions == 0u) |
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117 | return; |
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118 | |||
119 | // Block until we can transmit a DNS response packet |
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120 | while(!UDPIsPutReady(MySocket)); |
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121 | |||
122 | // Write DNS response packet |
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123 | UDPPutArray((BYTE*)&DNSHeader.wTransactionID, 2); // 2 byte Transaction ID |
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124 | if(DNSHeader.wFlags & 0x0100) |
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125 | UDPPut(0x81); // Message is a response with recursion desired |
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126 | else |
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127 | UDPPut(0x80); // Message is a response without recursion desired flag set |
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128 | UDPPut(0x80); // Recursion available |
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129 | UDPPut(0x00); // 0x0000 Questions |
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130 | UDPPut(0x00); |
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131 | UDPPut(0x00); // 0x0001 Answers RRs |
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132 | UDPPut(0x01); |
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133 | UDPPut(0x00); // 0x0000 Authority RRs |
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134 | UDPPut(0x00); |
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135 | UDPPut(0x00); // 0x0000 Additional RRs |
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136 | UDPPut(0x00); |
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137 | DNSCopyRXNameToTX(); // Copy hostname of first question over to TX packet |
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138 | UDPPut(0x00); // Type A Host address |
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139 | UDPPut(0x01); |
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140 | UDPPut(0x00); // Class INternet |
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141 | UDPPut(0x01); |
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142 | UDPPut(0x00); // Time to Live 10 seconds |
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143 | UDPPut(0x00); |
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144 | UDPPut(0x00); |
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145 | UDPPut(0x0A); |
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146 | UDPPut(0x00); // Data Length 4 bytes |
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147 | UDPPut(0x04); |
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148 | UDPPutArray((BYTE*)&AppConfig.MyIPAddr.Val, 4); // Our IP address |
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149 | |||
150 | UDPFlush(); |
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151 | } |
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152 | |||
153 | |||
154 | |||
155 | /***************************************************************************** |
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156 | Function: |
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157 | static void DNSCopyRXNameToTX(void) |
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158 | |||
159 | Summary: |
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160 | Copies a DNS hostname, possibly including name compression, from the RX |
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161 | packet to the TX packet (without name compression in TX case). |
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162 | |||
163 | Description: |
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164 | None |
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165 | |||
166 | Precondition: |
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167 | RX pointer is set to currently point to the DNS name to copy |
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168 | |||
169 | Parameters: |
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170 | None |
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171 | |||
172 | Returns: |
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173 | None |
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174 | ***************************************************************************/ |
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175 | static void DNSCopyRXNameToTX(void) |
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176 | { |
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177 | WORD w; |
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178 | BYTE i; |
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179 | BYTE len; |
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180 | |||
181 | while(1) |
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182 | { |
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183 | // Get first byte which will tell us if this is a 16-bit pointer or the |
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184 | // length of the first of a series of labels |
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185 | if(!UDPGet(&i)) |
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186 | return; |
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187 | |||
188 | // Check if this is a pointer, if so, get the reminaing 8 bits and seek to the pointer value |
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189 | if((i & 0xC0u) == 0xC0u) |
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190 | { |
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191 | ((BYTE*)&w)[1] = i & 0x3F; |
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192 | UDPGet((BYTE*)&w); |
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193 | IPSetRxBuffer(sizeof(UDP_HEADER) + w); |
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194 | continue; |
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195 | } |
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196 | |||
197 | // Write the length byte |
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198 | len = i; |
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199 | UDPPut(len); |
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200 | |||
201 | // Exit if we've reached a zero length label |
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202 | if(len == 0u) |
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203 | return; |
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204 | |||
205 | // Copy all of the bytes in this label |
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206 | while(len--) |
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207 | { |
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208 | UDPGet(&i); |
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209 | UDPPut(i); |
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210 | } |
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211 | } |
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212 | } |
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213 | |||
214 | #endif //#if defined(STACK_USE_DNS_SERVER) |
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