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1 /* |
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2 * Copyright 2007 Baylor University |
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3 * |
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4 * Licensed under the Apache License, Version 2.0 (the "License"); |
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5 * you may not use this file except in compliance with the License. |
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6 * You may obtain a copy of the License at |
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7 * |
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8 * http://www.apache.org/licenses/LICENSE-2.0 |
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9 * |
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10 * Unless required by applicable law or agreed to in writing, software |
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11 * distributed under the License is distributed on an "AS IS" BASIS, |
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12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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13 * See the License for the specific language governing permissions and |
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14 * limitations under the License. |
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15 */ |
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16 |
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17 #include <arpa/inet.h> // for hton[ls] and ntoh[ls] |
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18 #include "Util.h" |
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19 #include "RIBDTLV.h" |
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20 |
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21 namespace prophet |
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22 { |
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23 |
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24 RIBDTLV::RIBDTLV(const Dictionary& ribd) |
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25 : BaseTLV(BaseTLV::RIBD_TLV), ribd_(ribd) |
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26 { |
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27 length_ = RIBDTLVHeaderSize; |
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28 length_ += ribd_.guess_ribd_size(RoutingAddressStringSize); |
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29 } |
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30 |
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31 RIBDTLV::RIBDTLV() |
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32 : BaseTLV(BaseTLV::RIBD_TLV) {} |
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33 |
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34 size_t |
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35 RIBDTLV::write_ras_entry(u_int16_t sid, |
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36 const std::string& dest_id, |
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37 u_char* bp, size_t len) const |
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38 { |
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39 // weed out the oddball |
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40 if (bp == NULL) return 0; |
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41 |
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42 // align length of dest_id to 4 byte boundary |
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43 size_t copylen = FOUR_BYTE_ALIGN(dest_id.length()); |
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44 |
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45 // make sure the lengths match up with the provided buffer |
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46 if (RoutingAddressStringSize + copylen > len) return 0; |
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47 |
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48 // initialize to sizeof overhead |
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49 size_t retval = RoutingAddressStringSize; |
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50 |
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51 // start writing out to buffer |
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52 RoutingAddressString* ras = (RoutingAddressString*) bp; |
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53 ras->string_id = htons(sid); |
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54 ras->length = dest_id.length() & 0xff; |
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55 memcpy(&ras->ra_string[0],dest_id.c_str(),dest_id.length()); |
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56 retval += copylen; // 32-bit alignment |
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57 |
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58 // zero out slack, if any |
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59 while (copylen-- > ras->length) |
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60 ras->ra_string[copylen] = '\0'; |
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61 |
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62 return retval; |
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63 } |
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64 |
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65 size_t |
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66 RIBDTLV::serialize(u_char* bp, size_t len) const |
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67 { |
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68 // weed out the oddball |
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69 if (bp == NULL) return 0; |
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70 if (typecode_ != BaseTLV::RIBD_TLV) return 0; |
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71 |
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72 // estimate final size of TLV, check length of inbound buffer |
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73 size_t ribd_sz = ribd_.guess_ribd_size(RoutingAddressStringSize); |
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74 if (ribd_sz + RIBDTLVHeaderSize > len) return 0; |
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75 |
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76 // initialize accounting |
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77 size_t ribd_entry_count = 0; |
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78 length_ = 0; |
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79 RIBDTLVHeader* hdr = (RIBDTLVHeader*) bp; |
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80 memset(hdr,0,RIBDTLVHeaderSize); |
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81 |
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82 // write out to buffer, skipping header (for now) |
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83 bp += RIBDTLVHeaderSize; |
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84 length_ += RIBDTLVHeaderSize; |
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85 |
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86 // write out individual RIBD entries |
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87 for (Dictionary::const_iterator i = ribd_.begin(); i != ribd_.end(); i++) |
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88 { |
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89 // shouldn't happen, but test anyways |
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90 if ((*i).first < 2) |
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91 continue; // local and remote peers are implied as 0 and 1 |
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92 |
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93 size_t bytes_written = 0; |
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94 if ((bytes_written = |
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95 write_ras_entry((*i).first,(*i).second,bp,len)) == 0) |
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96 break; |
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97 |
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98 bp += bytes_written; |
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99 len -= bytes_written; |
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100 length_ += bytes_written; |
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101 |
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102 ribd_entry_count++; |
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103 } |
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104 |
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105 // fill in header for amounts successfully written |
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106 hdr->type = BaseTLV::RIBD_TLV; |
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107 hdr->flags = 0; |
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108 hdr->length = htons(length_); |
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109 hdr->entry_count = htons(ribd_entry_count); |
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110 |
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111 return length_; |
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112 } |
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113 |
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114 size_t |
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115 RIBDTLV::read_ras_entry(u_int16_t* sid, |
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116 std::string& dest_id, |
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117 const u_char* bp, size_t len) |
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118 { |
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119 // weed out the oddball |
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120 if (sid == NULL || bp == NULL) return 0; |
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121 |
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122 // reject too-tight bounds |
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123 if (RoutingAddressStringSize > len) return 0; |
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124 |
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125 RoutingAddressString* ras = (RoutingAddressString*) bp; |
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126 |
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127 // initialize to sizeof overhead |
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128 size_t retval = RoutingAddressStringSize; |
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129 |
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130 // must be even multiple of 4 bytes |
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131 size_t copylen = FOUR_BYTE_ALIGN(ras->length); |
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132 |
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133 // make sure the lengths match up |
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134 if (copylen > len - retval) return retval; |
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135 |
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136 // read into memory |
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137 *sid = ntohs(ras->string_id); |
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138 dest_id.assign((char*)&ras->ra_string[0],ras->length); |
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139 |
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140 // count what we read |
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141 retval += copylen; |
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142 |
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143 return retval; |
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144 } |
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145 |
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146 bool |
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147 RIBDTLV::deserialize(const u_char* bp, size_t len) |
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148 { |
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149 RIBDTLVHeader* hdr = (RIBDTLVHeader*) bp; |
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150 |
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151 // weed out the oddball |
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152 if (bp == NULL) return false; |
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153 |
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154 // Enforce typecode expectation |
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155 if (hdr->type != RIBD_TLV) return false; |
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156 |
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157 // Inbound buffer must be at least as big as the overhead |
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158 if (len < RIBDTLVHeaderSize) return false; |
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159 |
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160 // Fail out if lengths don't match up |
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161 length_ = ntohs(hdr->length); |
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162 if (len < length_) return false; |
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163 |
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164 flags_ = hdr->flags; |
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165 |
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166 size_t ribd_entry_count = ntohs(hdr->entry_count); |
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167 |
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168 // Now that the header is parsed, move past to the first RIBD entry |
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169 bp += RIBDTLVHeaderSize; |
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170 |
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171 size_t amt_read = RIBDTLVHeaderSize; |
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172 len -= RIBDTLVHeaderSize; |
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173 |
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174 u_int16_t sid; |
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175 std::string dest_id; |
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176 ribd_.clear(); |
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177 while (ribd_entry_count-- > 0) |
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178 { |
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179 // deserialize RAS from buffer |
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180 size_t bytes_read = read_ras_entry(&sid,dest_id,bp,len); |
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181 |
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182 // abort on error |
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183 if (bytes_read == 0) break; |
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184 |
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185 // store this dictionary entry |
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186 if(ribd_.assign(dest_id,sid) == false) break; |
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187 |
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188 len -= bytes_read; |
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189 bp += bytes_read; |
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190 amt_read += bytes_read; |
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191 } |
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192 |
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193 return (amt_read == length_); |
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194 } |
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195 |
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196 const Dictionary& |
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197 RIBDTLV::ribd(const std::string& sender, const std::string& receiver) |
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198 { |
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199 ribd_.assign(sender,0); |
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200 ribd_.assign(receiver,1); |
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201 return ribd_; |
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202 } |
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203 |
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204 }; // namespace prophet |