1 | // [License]
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2 | // The Ariba-Underlay Copyright
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3 | //
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4 | // Copyright (c) 2008-2009, Institute of Telematics, UniversitÀt Karlsruhe (TH)
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5 | //
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6 | // Institute of Telematics
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7 | // UniversitÀt Karlsruhe (TH)
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8 | // Zirkel 2, 76128 Karlsruhe
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9 | // Germany
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10 | //
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11 | // Redistribution and use in source and binary forms, with or without
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12 | // modification, are permitted provided that the following conditions are
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13 | // met:
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14 | //
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15 | // 1. Redistributions of source code must retain the above copyright
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16 | // notice, this list of conditions and the following disclaimer.
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17 | // 2. Redistributions in binary form must reproduce the above copyright
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18 | // notice, this list of conditions and the following disclaimer in the
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19 | // documentation and/or other materials provided with the distribution.
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20 | //
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21 | // THIS SOFTWARE IS PROVIDED BY THE INSTITUTE OF TELEMATICS ``AS IS'' AND
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22 | // ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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23 | // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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24 | // PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE ARIBA PROJECT OR
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25 | // CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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26 | // EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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27 | // PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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28 | // PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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29 | // LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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30 | // NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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31 | // SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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32 | //
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33 | // The views and conclusions contained in the software and documentation
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34 | // are those of the authors and should not be interpreted as representing
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35 | // official policies, either expressed or implied, of the Institute of
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36 | // Telematics.
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37 | // [License]
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38 |
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39 | #include "ariba/overlay/BaseOverlay.h"
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40 | #include "ariba/overlay/messages/OverlayMsg.h"
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41 |
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42 | #include "Chord.h"
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43 | #include "detail/chord_routing_table.hpp"
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44 |
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45 | #include "messages/Discovery.h"
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46 |
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47 | namespace ariba {
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48 | namespace overlay {
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49 |
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50 | enum signalMessageTypes {
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51 | typeDiscovery = OverlayMsg::typeSignalingStart + 0x01,
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52 | typeLeave = OverlayMsg::typeSignalingStart + 0x02,
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53 | };
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54 |
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55 | typedef chord_routing_table::item route_item;
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56 |
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57 | use_logging_cpp( Chord );
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58 |
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59 | Chord::Chord(BaseOverlay& _baseoverlay, const NodeID& _nodeid,
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60 | OverlayStructureEvents* _eventsReceiver, const OverlayParameterSet& param) :
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61 | OverlayInterface(_baseoverlay, _nodeid, _eventsReceiver, param) {
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62 |
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63 | // create routing table
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64 | this->table = new chord_routing_table(_nodeid, 4);
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65 | orphan_removal_counter = 0;
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66 | discovery_count = 0;
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67 | stabilize_counter = 0;
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68 | stabilize_finger = 0;
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69 | }
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70 |
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71 | Chord::~Chord() {
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72 |
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73 | // delete routing table
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74 | delete table;
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75 | }
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76 |
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77 | /// helper: sets up a link using the base overlay
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78 | LinkID Chord::setup(const EndpointDescriptor& endpoint, const NodeID& remote ) {
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79 |
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80 | // check if we already have a connection
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81 | for (int i=0; i<table->size(); i++)
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82 | if ((*table)[i]->ref_count > 0 && (*table)[i]->id == remote && !((*table)[i]->info.isUnspecified()))
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83 | return LinkID::UNSPECIFIED;
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84 |
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85 | // check if we are already trying to establish a link
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86 | for (size_t i=0; i<pending.size(); i++)
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87 | if ( pending[i] == remote ) {
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88 | logging_debug("Already trying to establish a link to node "
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89 | << remote.toString() );
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90 | return LinkID::UNSPECIFIED;
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91 | }
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92 |
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93 | // adding node to list of pending connections
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94 | pending.push_back( remote );
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95 |
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96 | logging_info("Request to setup link to " << endpoint.toString() );
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97 |
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98 | // establish link via base overlay
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99 | return baseoverlay.establishLink( endpoint, remote,
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100 | OverlayInterface::OVERLAY_SERVICE_ID );
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101 | }
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102 |
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103 | /// helper: sends a message using the "base overlay"
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104 | seqnum_t Chord::send( OverlayMsg* msg, const LinkID& link ) {
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105 | if (link.isUnspecified()) return 0;
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106 | return baseoverlay.send_link( msg, link );
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107 | }
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108 |
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109 | /// sends a discovery message
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110 | void Chord::send_discovery_to(const NodeID& remote, int ttl) {
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111 | LinkID link = getNextLinkId(remote);
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112 | if ( remote == nodeid || link.isUnspecified()) return;
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113 | if ( table->size() == 0 ) return;
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114 | ttl = 2;
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115 |
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116 | OverlayMsg msg( typeDiscovery );
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117 | msg.setRegisterRelay(true);
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118 | Discovery dmsg( Discovery::normal, (uint8_t)ttl, baseoverlay.getEndpointDescriptor() );
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119 | msg.encapsulate(&dmsg);
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120 |
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121 | // send to node
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122 | baseoverlay.send_node( &msg, remote );
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123 | }
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124 |
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125 | void Chord::discover_neighbors( const LinkID& link ) {
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126 | uint8_t ttl = 4;
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127 | {
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128 | // send predecessor discovery
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129 | OverlayMsg msg( typeDiscovery );
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130 | msg.setRegisterRelay(true);
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131 | Discovery dmsg( Discovery::predecessor, ttl,
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132 | baseoverlay.getEndpointDescriptor() );
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133 | msg.encapsulate(&dmsg);
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134 | send(&msg, link);
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135 | }
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136 | {
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137 | // send successor discovery
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138 | OverlayMsg msg( typeDiscovery );
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139 | msg.setSourceEndpoint( baseoverlay.getEndpointDescriptor() );
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140 | msg.setRegisterRelay(true);
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141 | Discovery dmsg( Discovery::successor, ttl,
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142 | baseoverlay.getEndpointDescriptor() );
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143 | msg.encapsulate(&dmsg);
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144 | send(&msg, link);
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145 | }
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146 | }
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147 |
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148 |
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149 | void Chord::createOverlay() {
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150 | }
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151 |
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152 | void Chord::deleteOverlay() {
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153 |
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154 | }
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155 |
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156 | void Chord::joinOverlay(const EndpointDescriptor& boot) {
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157 | logging_info( "joining Chord overlay structure through end-point " <<
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158 | (boot.isUnspecified() ? "local" : boot.toString()) );
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159 |
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160 | // initiator? no->setup first link
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161 | if (!boot.isUnspecified())
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162 | bootstrapLinks.push_back( setup(boot) );
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163 |
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164 | // timer for stabilization management
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165 | Timer::setInterval(1000);
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166 | Timer::start();
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167 | }
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168 |
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169 | void Chord::leaveOverlay() {
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170 | Timer::stop();
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171 | for (size_t i = 0; i < table->size(); i++) {
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172 | route_item* it = (*table)[i];
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173 | OverlayMsg msg( typeLeave );
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174 | send( &msg, it->info );
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175 | }
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176 | }
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177 |
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178 | /// @see OverlayInterface.h
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179 | const EndpointDescriptor& Chord::resolveNode(const NodeID& node) {
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180 | const route_item* item = table->get(node);
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181 | if (item == NULL || item->info.isUnspecified()) return EndpointDescriptor::UNSPECIFIED();
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182 | return baseoverlay.getEndpointDescriptor(item->info);
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183 | }
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184 |
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185 | /// @see OverlayInterface.h
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186 | const LinkID& Chord::getNextLinkId( const NodeID& id ) const {
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187 | // get next hop
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188 | const route_item* item = table->get_next_hop(id);
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189 |
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190 | // returns a unspecified id when this is itself
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191 | if (item == NULL || item->id == nodeid)
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192 | return LinkID::UNSPECIFIED;
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193 |
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194 | /// return routing info
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195 | return item->info;
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196 | }
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197 |
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198 | OverlayInterface::NodeList Chord::getKnownNodes(bool deep) const {
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199 | OverlayInterface::NodeList nodelist;
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200 |
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201 | if( deep ){
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202 | // all nodes that I know, fingers, succ/pred
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203 | for (size_t i = 0; i < table->size(); i++){
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204 | if ((*table)[i]->ref_count != 0
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205 | && !(*table)[i]->info.isUnspecified())
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206 | nodelist.push_back((*table)[i]->id);
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207 | }
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208 | } else {
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209 | // only succ and pred
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210 | if( table->get_predesessor() != NULL ){
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211 | nodelist.push_back( *(table->get_predesessor()) );
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212 | }
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213 | if( table->get_successor() != NULL ){
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214 | OverlayInterface::NodeList::iterator i =
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215 | std::find( nodelist.begin(), nodelist.end(), *(table->get_successor()) );
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216 | if( i == nodelist.end() )
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217 | nodelist.push_back( *(table->get_successor()) );
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218 | }
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219 | }
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220 |
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221 | return nodelist;
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222 | }
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223 |
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224 | /// @see CommunicationListener.h
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225 | /// @see OverlayInterface.h
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226 | void Chord::onLinkUp(const LinkID& lnk, const NodeID& remote) {
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227 | logging_info("link_up: link=" << lnk.toString() << " remote=" <<
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228 | remote.toString() );
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229 | for (vector<NodeID>::iterator i=pending.begin(); i!=pending.end(); i++)
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230 | if (*i == remote) {
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231 | pending.erase(i);
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232 | break;
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233 | }
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234 |
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235 | if (remote==nodeid) {
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236 | baseoverlay.dropLink(lnk);
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237 | return;
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238 | }
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239 |
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240 | route_item* item = table->insert(remote);
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241 |
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242 | // item added to routing table?
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243 | if (item != NULL) { // yes-> add to routing table
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244 | logging_info("new routing neighbor: " << remote.toString()
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245 | << " with link " << lnk.toString());
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246 | // replace with new link
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247 | if (!item->info.isUnspecified() || item->info!=lnk)
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248 | baseoverlay.dropLink(item->info);
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249 | item->info = lnk;
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250 |
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251 | // discover neighbors of new overlay neighbor
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252 | showLinks();
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253 | } else { // no-> add orphan entry to routing table
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254 | logging_info("new orphan: " << remote.toString()
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255 | << " with link " << lnk.toString());
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256 | table->insert_orphan(remote)->info = lnk;
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257 | }
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258 |
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259 | // erase bootstrap link
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260 | vector<LinkID>::iterator it = std::find(bootstrapLinks.begin(), bootstrapLinks.end(), lnk);
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261 | if( it != bootstrapLinks.end() ) bootstrapLinks.erase( it );
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262 | }
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263 |
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264 | /// @see CommunicationListener.h or @see OverlayInterface.h
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265 | void Chord::onLinkDown(const LinkID& lnk, const NodeID& remote) {
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266 | logging_debug("link_down: link=" << lnk.toString() << " remote=" <<
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267 | remote.toString() );
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268 |
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269 | // remove link from routing table
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270 | route_item* item = table->get(remote);
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271 | if (item!=NULL && item->info==lnk) {
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272 | item->info = LinkID::UNSPECIFIED;
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273 | table->remove(remote);
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274 | }
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275 | }
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276 |
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277 | /// @see CommunicationListener.h
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278 | /// @see OverlayInterface.h
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279 | void Chord::onMessage(const DataMessage& msg, const NodeID& remote,
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280 | const LinkID& link) {
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281 |
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282 | // decode message
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283 | OverlayMsg* m = dynamic_cast<OverlayMsg*>(msg.getMessage());
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284 | if (m == NULL) return;
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285 |
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286 | // handle messages
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287 | switch (m->getType()) {
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288 |
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289 | // discovery request
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290 | case typeDiscovery: {
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291 | // decapsulate message
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292 | Discovery* dmsg = m->decapsulate<Discovery> ();
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293 | logging_debug("Received discovery message with"
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294 | << " src=" << m->getSourceNode().toString()
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295 | << " dst=" << m->getDestinationNode().toString()
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296 | << " ttl=" << (int)dmsg->getTTL()
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297 | << " type=" << (int)dmsg->getType()
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298 | );
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299 |
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300 | // add discovery node id
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301 | bool found = false;
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302 | BOOST_FOREACH( NodeID& value, discovery )
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303 | if (value == m->getSourceNode()) {
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304 | found = true;
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305 | break;
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306 | }
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307 | if (!found) discovery.push_back(m->getSourceNode());
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308 |
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309 | // check if source node can be added to routing table and setup link
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310 | if (m->getSourceNode() != nodeid)
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311 | setup( dmsg->getEndpoint(), m->getSourceNode() );
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312 |
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313 | // delegate discovery message
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314 | switch (dmsg->getType()) {
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315 |
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316 | // normal: route discovery message like every other message
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317 | case Discovery::normal: {
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318 | // closest node? yes-> split to follow successor and predecessor
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319 | if ( table->is_closest_to(m->getDestinationNode()) ) {
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320 | logging_debug("Discovery split:");
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321 | if (!table->get_successor()->isUnspecified()) {
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322 | OverlayMsg omsg(*m);
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323 | dmsg->setType(Discovery::successor);
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324 | omsg.encapsulate(dmsg);
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325 | logging_debug("* Routing to successor "
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326 | << table->get_successor()->toString() );
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327 | baseoverlay.send( &omsg, *table->get_successor() );
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328 | }
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329 |
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330 | // send predecessor message
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331 | if (!table->get_predesessor()->isUnspecified()) {
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332 | OverlayMsg omsg(*m);
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333 | dmsg->setType(Discovery::predecessor);
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334 | omsg.encapsulate(dmsg);
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335 | logging_debug("* Routing to predecessor "
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336 | << table->get_predesessor()->toString() );
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337 | baseoverlay.send( &omsg, *table->get_predesessor() );
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338 | }
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339 | }
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340 | // no-> route message
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341 | else {
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342 | baseoverlay.route( m );
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343 | }
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344 | break;
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345 | }
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346 |
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347 | // successor mode: follow the successor until TTL is zero
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348 | case Discovery::successor:
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349 | case Discovery::predecessor: {
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350 | // reached destination? no->forward!
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351 | if (m->getDestinationNode() != nodeid) {
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352 | OverlayMsg omsg(*m);
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353 | omsg.encapsulate(dmsg);
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354 | omsg.setService(OverlayInterface::OVERLAY_SERVICE_ID);
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355 | baseoverlay.send(&omsg, omsg.getDestinationNode());
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356 | break;
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357 | }
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358 |
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359 | // time to live ended? yes-> stop routing
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360 | if (dmsg->getTTL() == 0 || dmsg->getTTL() > 10) break;
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361 |
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362 | // decrease time-to-live
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363 | dmsg->setTTL(dmsg->getTTL() - 1);
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364 |
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365 | const route_item* item = NULL;
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366 | if (dmsg->getType() == Discovery::successor &&
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367 | table->get_successor() != NULL) {
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368 | item = table->get(*table->get_successor());
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369 | } else {
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370 | if (table->get_predesessor()!=NULL)
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371 | item = table->get(*table->get_predesessor());
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372 | }
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373 | if (item == NULL)
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374 | break;
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375 |
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376 | logging_debug("Routing discovery message to succ/pred "
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377 | << item->id.toString() );
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378 | OverlayMsg omsg(*m);
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379 | omsg.encapsulate(dmsg);
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380 | omsg.setDestinationNode(item->id);
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381 | omsg.setService(OverlayInterface::OVERLAY_SERVICE_ID);
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382 | baseoverlay.send(&omsg, omsg.getDestinationNode());
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383 | break;
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384 | }}
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385 | delete dmsg;
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386 | break;
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387 | }
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388 |
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389 | // leave
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390 | case typeLeave: {
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391 | if (link!=LinkID::UNSPECIFIED) {
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392 | route_item* item = table->get(remote);
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393 | if (item!=NULL) item->info = LinkID::UNSPECIFIED;
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394 | table->remove(remote);
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395 | baseoverlay.dropLink(link);
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396 | }
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397 | break;
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398 | }}
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399 | }
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400 |
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401 | void Chord::eventFunction() {
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402 | stabilize_counter++;
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403 | if (stabilize_counter < 0 || stabilize_counter == 4) {
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404 |
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405 | // reset counter
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406 | stabilize_counter = 0;
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407 |
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408 | // clear pending connections
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409 | pending.clear();
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410 |
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411 | // get number of real neighbors
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412 | size_t numNeighbors = 0;
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413 | for (size_t i = 0; i < table->size(); i++) {
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414 | route_item* it = (*table)[i];
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415 | if (it->ref_count != 0 && !it->info.isUnspecified()) numNeighbors++;
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416 | }
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417 | logging_info("Running stabilization: #links="
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418 | << table->size() << " #neighbors=" << numNeighbors );
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419 |
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420 | // updating neighbors
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421 | logging_debug("Discover new ring neighbors");
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422 | for (int i=0; i<table->size(); i++) {
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423 | LinkID id = (*table)[i]->info;
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424 | if (!id.isUnspecified()) discover_neighbors(id);
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425 | }
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426 |
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427 | // sending discovery
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428 | logging_debug("Sending discovery message to my neighbors and fingers");
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429 | stabilize_finger = ((stabilize_finger+1) % table->get_finger_table_size() );
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430 | const NodeID disc = table->get_finger_table(stabilize_finger).get_compare().get_center();
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431 | if (disc != nodeid)
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432 | send_discovery_to(disc);
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433 |
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434 | // remove orphan links
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435 | orphan_removal_counter++;
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436 | if (orphan_removal_counter <0 || orphan_removal_counter >= 2) {
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437 | logging_info("Discovered nodes: ");
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438 | BOOST_FOREACH( NodeID& id, discovery )
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439 | logging_info("* " << id.toString());
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440 | discovery.clear();
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441 | logging_info("Running orphan removal");
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442 | orphan_removal_counter = 0;
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443 | for (size_t i = 0; i < table->size(); i++) {
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444 | route_item* it = (*table)[i];
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445 | if (it->ref_count == 0 && !it->info.isUnspecified()) {
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446 | logging_info("Dropping orphaned link " << it->info.toString() << " to " << it->id.toString());
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447 | table->insert(it->id);
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448 | if (it->ref_count==0) {
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449 | LinkID id = it->info;
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450 | it->info = LinkID::UNSPECIFIED;
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451 | baseoverlay.dropLink(id);
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452 | }
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453 | }
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454 | }
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455 | }
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456 | }
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457 | }
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458 |
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459 | void Chord::showLinks() {
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460 | logging_info("--- chord routing information ----------------------------------");
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461 | logging_info("predecessor: " << (table->get_predesessor()==NULL? "<none>" :
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462 | table->get_predesessor()->toString()) );
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463 | logging_info("node_id : " << nodeid.toString() );
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464 | logging_info("successor : " << (table->get_successor()==NULL? "<none>" :
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465 | table->get_successor()->toString()));
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466 | logging_info("----------------------------------------------------------------");
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467 | }
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468 |
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469 | }} // namespace ariba, overlay
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