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23 | "use strict";
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24 |
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25 | var ipaddr = require('ipaddr.js'),
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26 | name = require('./name');
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27 |
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28 | var Struct = exports.Struct = function (field_name, format) {
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29 | var size, write, read;
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30 |
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31 | switch (format) {
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32 | case 'B':
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33 | write = 'writeUInt8';
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34 | read = 'readUInt8';
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35 | size = 1;
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36 | break;
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37 | case 'H':
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38 | write = 'writeUInt16BE';
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39 | read = 'readUInt16BE';
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40 | size = 2;
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41 | break;
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42 | case 'I':
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43 | write = 'writeUInt32BE';
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44 | read = 'readUInt32BE';
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45 | size = 4;
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46 | break;
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47 | case 'i':
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48 | write = 'writeInt32BE';
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49 | read = 'readInt32BE';
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50 | size = 4;
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51 | break;
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52 | };
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53 |
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54 | var field = {
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55 | name: field_name,
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56 | default: 0,
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57 | pack: function (value, buf, pos) {
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58 | buf[write](value, pos);
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59 | return size;
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60 | },
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61 | unpack: function (buff, pos) {
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62 | var value = buff[read](pos);
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63 | return {
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64 | read: size,
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65 | value: value,
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66 | };
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67 | },
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68 | size: size,
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69 | };
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70 |
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71 | return field;
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72 | };
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73 |
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74 | var SubField = exports.SubField = function (field_name, parent, shift, mask) {
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75 | var field = {
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76 | name: field_name,
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77 | default: 0,
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78 | get: function (self) {
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79 | var v = self[parent];
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80 | return (v & mask) >> shift;
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81 | },
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82 | set: function (self, value) {
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83 | var cval = self[parent] - (self[parent] & mask);
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84 | cval += (value << shift) & mask;
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85 | self[parent] = cval;
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86 | },
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87 | };
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88 | return field;
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89 | };
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90 |
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91 | var Label = exports.Label = function (field_name) {
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92 | var field = {
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93 | name: field_name,
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94 | default: '',
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95 | pack: function (value, buf, pos) {
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96 | return name.pack(value, buf, pos, this.parent.label_index_);
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97 | },
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98 | unpack: name.unpack,
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99 | size: function (value) {
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100 | return value.length;
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101 | },
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102 | };
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103 |
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104 | return field;
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105 | };
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106 |
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107 | var IPAddress = exports.IPAddress = function (field_name, byte_length) {
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108 | var size;
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109 |
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110 | switch (byte_length) {
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111 | case 4:
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112 | size = 4;
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113 | break;
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114 | case 6:
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115 | size = 16;
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116 | break;
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117 | };
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118 |
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119 | var field = {
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120 | name: field_name,
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121 | size: size,
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122 | pack: function (value, buf, pos) {
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123 | var i, bytes, ret;
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124 | bytes = ipaddr.parse(value).toByteArray();
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125 |
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126 | bytes.forEach(function (b, i) {
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127 | buf.writeUInt8(b, i + pos);
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128 | });
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129 |
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130 | return bytes.length;
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131 | },
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132 | unpack: function (buff, pos) {
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133 | var i, Kind, read = 0, bytes = [];
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134 |
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135 | switch (byte_length) {
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136 | case 4:
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137 | Kind = ipaddr.IPv4;
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138 | for (i = 0; i < byte_length; i++) {
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139 | bytes.push(buff.readUInt8(pos));
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140 | read += 1;
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141 | pos += 1;
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142 | }
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143 | break;
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144 | case 6:
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145 | Kind = ipaddr.IPv6;
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146 | for (i = 0; i < 8; i++) {
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147 | bytes.push(buff.readUInt16BE(pos));
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148 | read += 2;
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149 | pos += 2;
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150 | }
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151 | break;
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152 | }
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153 |
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154 | return {
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155 | read: read,
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156 | value: new Kind(bytes).toString(),
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157 | };
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158 | },
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159 | };
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160 |
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161 | return field;
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162 | };
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163 |
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164 | var BufferField = exports.BufferField = function (field_name, format) {
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165 | var field = {
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166 | name: field_name,
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167 | pack: function (value, buf, pos) {
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168 | var len = 2;
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169 | buf.writeUInt16BE(value.length, pos);
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170 | value.copy(buf, pos + len, 0, value.length);
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171 | return len + value.length;
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172 | },
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173 | unpack: function (buff, pos) {
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174 | var value_len, value, size, field_pos, start = pos;
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175 |
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176 | value_len = buff.readUInt16BE(pos);
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177 | size = 2;
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178 |
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179 | pos += size;
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180 | field_pos = pos;
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181 |
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182 | value = buff.slice(pos, pos + value_len);
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183 | pos += value_len;
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184 |
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185 | return {
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186 | read: pos - start,
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187 | value: value,
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188 | field_position: field_pos,
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189 | };
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190 | },
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191 | size: function (value) {
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192 | return value.length;
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193 | },
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194 | };
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195 |
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196 | return field;
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197 | };
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198 |
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199 | var CharString = exports.CharString = function (field_name) {
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200 | var field = {
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201 | name: field_name,
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202 | value: '',
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203 | get: function (self) {
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204 | return self.rdata.toString('ascii', 1, self.rdata.readUInt8(0) + 1);
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205 | },
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206 | set: function (self, value) {
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207 | var v = new Buffer(value.length + 1);
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208 | v.writeUInt8(value.length, 0);
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209 | v.write(value, 1);
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210 | self.rdata = v;
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211 | },
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212 | size: function (value) {
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213 | return value.length;
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214 | },
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215 | };
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216 |
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217 | return field;
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218 | };
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