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 |
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41 | #include "Chord.h"
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42 | #include "messages/ChordMessage.h"
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43 | #include "messages/Discovery.h"
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44 |
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45 | #include "detail/chord_routing_table.hpp"
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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 | typedef chord_routing_table::item route_item;
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51 |
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52 | use_logging_cpp( Chord );
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53 |
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54 | Chord::Chord(BaseOverlay& _baseoverlay, const NodeID& _nodeid,
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55 | OverlayStructureEvents* _eventsReceiver, const OverlayParameterSet& param) :
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56 | OverlayInterface(_baseoverlay, _nodeid, _eventsReceiver, param) {
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57 |
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58 | // create routing table
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59 | this->table = new chord_routing_table(_nodeid, 2);
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60 | orphan_removal_counter = 0;
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61 | stabilize_counter = 0;
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62 | stabilize_finger = 0;
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63 | }
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64 |
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65 | Chord::~Chord() {
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66 |
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67 | // delete routing table
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68 | delete table;
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69 | }
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70 |
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71 | /// helper: sets up a link using the base overlay
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72 | LinkID Chord::setup(const EndpointDescriptor& endp, const NodeID& node) {
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73 |
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74 | logging_debug("request to setup link to " << endp.toString() );
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75 |
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76 | for (size_t i=0; i<pending.size(); i++)
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77 | if (pending[i]==node) return LinkID::UNSPECIFIED;
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78 | pending.push_back(node);
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79 |
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80 | // establish link via base overlay
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81 | return baseoverlay.establishLink(endp, node, OverlayInterface::OVERLAY_SERVICE_ID);
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82 | }
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83 |
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84 | /// helper: sends a message using the "base overlay"
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85 | seqnum_t Chord::send(Message* msg, const LinkID& link) {
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86 | if (link.isUnspecified()) return 0;
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87 | return baseoverlay.sendMessage(msg, link);
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88 | }
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89 |
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90 | /// sends a discovery message
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91 | void Chord::send_discovery_to(const NodeID& destination, int ttl) {
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92 | // logging_debug("Initiating discovery of " << destination.toString() );
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93 | Message msg;
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94 | ChordMessage cmsg(ChordMessage::discovery, nodeid, destination);
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95 | Discovery dmsg;
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96 | dmsg.setSourceEndpoint(&baseoverlay.getEndpointDescriptor());
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97 | dmsg.setFollowType(Discovery::normal);
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98 | dmsg.setTTL((uint8_t) ttl);
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99 | cmsg.encapsulate(&dmsg);
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100 | msg.encapsulate(&cmsg);
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101 | this->onMessage(&msg, NodeID::UNSPECIFIED, LinkID::UNSPECIFIED);
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102 | }
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103 |
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104 | void Chord::createOverlay() {
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105 | }
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106 |
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107 | void Chord::deleteOverlay() {
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108 |
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109 | }
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110 |
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111 | void Chord::joinOverlay(const EndpointDescriptor& boot) {
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112 | logging_info( "joining Chord overlay structure through end-point " <<
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113 | (boot.isUnspecified() ? "local" : boot.toString()) );
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114 |
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115 | // initiator? no->setup first link
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116 | if (!boot.isUnspecified())
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117 | bootstrapLinks.push_back( setup(boot) );
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118 |
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119 | // timer for stabilization management
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120 | Timer::setInterval(2500);
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121 | Timer::start();
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122 | }
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123 |
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124 | void Chord::leaveOverlay() {
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125 | Timer::stop();
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126 | for (size_t i = 0; i < table->size(); i++) {
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127 | route_item* it = (*table)[i];
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128 | ChordMessage msg(ChordMessage::leave, nodeid, it->id);
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129 | send(&msg,it->info);
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130 | }
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131 | }
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132 |
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133 | const EndpointDescriptor& Chord::resolveNode(const NodeID& node) {
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134 | const route_item* item = table->get(node);
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135 | if (item == NULL || item->info.isUnspecified()) return EndpointDescriptor::UNSPECIFIED;
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136 | return baseoverlay.getEndpointDescriptor(item->info);
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137 | }
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138 |
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139 | void Chord::routeMessage(const NodeID& destnode, Message* msg) {
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140 | // get next hop
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141 | const route_item* item = table->get_next_hop(destnode);
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142 |
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143 | // message for this node? yes-> delegate to base overlay
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144 | if (item->id == nodeid || destnode == nodeid)
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145 | baseoverlay.incomingRouteMessage( msg, LinkID::UNSPECIFIED, nodeid );
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146 |
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147 | else { // no-> send to next hop
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148 | ChordMessage cmsg(ChordMessage::route, nodeid, destnode);
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149 | cmsg.encapsulate(msg);
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150 | send(&cmsg, item->info);
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151 | }
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152 | }
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153 |
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154 | /// @see OverlayInterface.h
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155 | void Chord::routeMessage(const NodeID& node, const LinkID& link, Message* msg) {
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156 | logging_debug("Redirect over Chord to node id=" << node.toString()
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157 | << " link id=" << link.toString() );
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158 | ChordMessage cmsg(ChordMessage::route, nodeid, node);
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159 | cmsg.encapsulate(msg);
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160 | send(&cmsg, link);
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161 | }
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162 |
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163 | /// @see OverlayInterface.h
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164 | const LinkID& Chord::getNextLinkId( const NodeID& id ) const {
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165 | // get next hop
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166 | const route_item* item = table->get_next_hop(id);
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167 |
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168 | // returns a unspecified id when this is itself
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169 | if (item == NULL || item->id == nodeid)
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170 | return LinkID::UNSPECIFIED;
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171 |
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172 | /// return routing info
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173 | return item->info;
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174 | }
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175 |
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176 | OverlayInterface::NodeList Chord::getKnownNodes(bool deep) const {
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177 | OverlayInterface::NodeList nodelist;
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178 |
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179 | if( deep ){
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180 | // all nodes that I know, fingers, succ/pred
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181 | for (size_t i = 0; i < table->size(); i++){
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182 | if ((*table)[i]->ref_count != 0
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183 | && !(*table)[i]->info.isUnspecified())
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184 | nodelist.push_back((*table)[i]->id);
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185 | }
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186 | } else {
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187 | // only succ and pred
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188 | if( table->get_predesessor() != NULL ){
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189 | nodelist.push_back( *(table->get_predesessor()) );
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190 | }
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191 |
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192 | if( table->get_successor() != NULL ){
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193 |
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194 | OverlayInterface::NodeList::iterator i =
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195 | std::find( nodelist.begin(), nodelist.end(), *(table->get_successor()) );
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196 | if( i == nodelist.end() )
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197 | nodelist.push_back( *(table->get_successor()) );
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198 | }
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199 | }
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200 |
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201 | return nodelist;
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202 | }
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203 |
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204 | /// @see CommunicationListener.h
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205 | /// @see OverlayInterface.h
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206 | void Chord::onLinkUp(const LinkID& lnk, const NodeID& remote) {
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207 | logging_debug("link_up: link=" << lnk.toString() << " remote=" <<
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208 | remote.toString() );
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209 | for (vector<NodeID>::iterator i=pending.begin(); i!=pending.end(); i++)
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210 | if (*i == remote) {
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211 | pending.erase(i);
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212 | break;
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213 | }
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214 | route_item* item = table->insert(remote);
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215 |
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216 | // item added to routing table?
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217 | if (item != NULL) { // yes-> add to routing table
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218 | logging_info("new routing neighbor: " << remote.toString()
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219 | << " with link " << lnk.toString());
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220 | item->info = lnk;
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221 | } else { // no-> add orphan entry to routing table
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222 | logging_info("new orphan: " << remote.toString()
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223 | << " with link " << lnk.toString());
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224 | table->insert_orphan(remote)->info = lnk;
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225 | }
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226 |
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227 | vector<LinkID>::iterator it = std::find(bootstrapLinks.begin(), bootstrapLinks.end(), lnk);
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228 | if( it != bootstrapLinks.end() ) {
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229 | // send discovery over bootstrap
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230 | Message msg;
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231 | ChordMessage cmsg(ChordMessage::discovery, nodeid, destination);
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232 | Discovery dmsg;
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233 | dmsg.setSourceEndpoint(&baseoverlay.getEndpointDescriptor());
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234 | dmsg.setFollowType(Discovery::normal);
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235 | dmsg.setTTL((uint8_t) ttl);
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236 | cmsg.encapsulate(&dmsg);
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237 | msg.encapsulate(&cmsg);
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238 | send(&msg, lnk);
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239 | bootstrapLinks.erase( it );
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240 | }
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241 | }
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242 |
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243 | /// @see CommunicationListener.h or @see OverlayInterface.h
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244 | void Chord::onLinkDown(const LinkID& lnk, const NodeID& remote) {
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245 | logging_debug("link_down: link=" << lnk.toString() << " remote=" <<
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246 | remote.toString() );
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247 |
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248 | // remove link from routing table
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249 | route_item* item = table->get(remote);
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250 | if (item!=NULL) item->info = LinkID::UNSPECIFIED;
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251 | table->remove(remote);
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252 | }
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253 |
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254 | /// @see CommunicationListener.h
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255 | /// @see OverlayInterface.h
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256 | void Chord::onMessage(const DataMessage& msg, const NodeID& remote,
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257 | const LinkID& link) {
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258 |
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259 | // decode message
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260 | typedef ChordMessage M;
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261 | M* m = msg.getMessage()->convert<ChordMessage> ();
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262 | if (m == NULL) return;
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263 |
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264 | // handle messages
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265 | switch (m->getType()) {
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266 |
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267 | // invalid message
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268 | case M::invalid:
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269 | break;
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270 |
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271 | // route message with payload
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272 | case M::route: {
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273 | // find next hop
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274 | const route_item* item = table->get_next_hop(m->getDestination());
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275 |
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276 | // next hop == myself?
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277 | if (m->getDestination() == nodeid) { // yes-> route to base overlay
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278 | logging_debug("Send message to baseoverlay");
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279 | baseoverlay.incomingRouteMessage( m, item->info, remote );
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280 | }
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281 | // no-> route to next hop
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282 | else {
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283 | logging_debug("Route chord message to "
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284 | << item->id.toString() << " (destination=" << m->getDestination() << ")");
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285 | send(m, item->info);
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286 | }
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287 | break;
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288 | }
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289 |
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290 | // discovery request
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291 | case M::discovery: {
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292 | // decapsulate message
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293 | Discovery* dmsg = m->decapsulate<Discovery> ();
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294 | logging_debug("received discovery message with"
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295 | << " dest=" << m->getDestination().toString()
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296 | << " ttl=" << (int)dmsg->getTTL()
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297 | << " type=" << (int)dmsg->getFollowType()
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298 | );
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299 |
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300 | // check if source node can be added to routing table and setup link
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301 | if (m->getSource() != nodeid && table->is_insertable(m->getSource()))
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302 | setup(*dmsg->getSourceEndpoint(), m->getSource() );
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303 |
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304 | // delegate discovery message
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305 | switch (dmsg->getFollowType()) {
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306 |
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307 | // normal: route discovery message like every other message
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308 | case Discovery::normal:
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309 | // closest node? yes-> split to follow successor and predecessor
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310 | if (table->is_closest_to(m->getDestination())) {
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311 |
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312 | if (table->get_successor() != NULL) {
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313 | // send successor message
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314 | ChordMessage cmsg_s(*m);
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315 | Discovery dmsg_s(*dmsg);
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316 | dmsg_s.setFollowType(Discovery::successor);
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317 | cmsg_s.encapsulate(&dmsg_s);
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318 | route_item* succ_item = table->get(*table->get_successor());
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319 | logging_debug("split: routing discovery message to successor "
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320 | << succ_item->id.toString() );
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321 | send(&cmsg_s, succ_item->info);
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322 | }
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323 |
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324 | // send predecessor message
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325 | if (table->get_predesessor() != NULL) {
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326 | ChordMessage cmsg_p(*m);
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327 | Discovery dmsg_p(*dmsg);
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328 | dmsg_p.setFollowType(Discovery::predecessor);
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329 | cmsg_p.encapsulate(&dmsg_p);
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330 | route_item* pred_item = table->get(
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331 | *table->get_predesessor());
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332 | logging_debug("split: routing discovery message to predecessor "
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333 | << pred_item->id.toString() );
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334 | send(&cmsg_p, pred_item->info);
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335 | }
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336 | }
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337 | // no-> route message
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338 | else {
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339 | // find next hop
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340 | const route_item* item = table->get_next_hop(
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341 | m->getDestination());
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342 | if (item->id == nodeid) break;
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343 | logging_debug("routing discovery message to " <<
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344 | item->id.toString() );
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345 | send(m, item->info);
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346 | }
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347 | break;
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348 |
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349 | // successor mode: follow the successor until TTL is zero
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350 | case Discovery::successor:
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351 | case Discovery::predecessor: {
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352 | // time to live ended? yes-> stop routing
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353 | if (dmsg->getTTL() == 0) break;
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354 |
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355 | // decrease time-to-live
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356 | dmsg->setTTL(dmsg->getTTL() - 1);
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357 |
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358 | const route_item* item = NULL;
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359 | if (dmsg->getFollowType() == Discovery::successor &&
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360 | table->get_successor() != NULL) {
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361 | item = table->get(*table->get_successor());
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362 | } else {
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363 | if (table->get_predesessor()!=NULL)
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364 | item = table->get(*table->get_predesessor());
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365 | }
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366 | if (item == NULL) break;
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367 | logging_debug("routing discovery message to succ/pred "
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368 | << item->id.toString() );
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369 | ChordMessage cmsg(*m);
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370 | cmsg.encapsulate(dmsg);
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371 | send(&cmsg, item->info);
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372 | break;
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373 | }
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374 | }
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375 | break;
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376 | }
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377 |
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378 | // leave
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379 | case M::leave: {
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380 | if (link!=LinkID::UNSPECIFIED) {
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381 | route_item* item = table->get(remote);
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382 | if (item!=NULL) item->info = LinkID::UNSPECIFIED;
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383 | table->remove(remote);
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384 | baseoverlay.dropLink(link);
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385 | }
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386 | break;
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387 | }
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388 | }
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389 | }
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390 |
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391 | void Chord::eventFunction() {
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392 | stabilize_counter++;
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393 | if (stabilize_counter == 3) {
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394 | pending.clear();
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395 | size_t numNeighbors = 0;
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396 | for (size_t i = 0; i < table->size(); i++) {
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397 | route_item* it = (*table)[i];
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398 | if (it->ref_count != 0 && !it->info.isUnspecified()) numNeighbors++;
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399 | }
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400 | logging_info("Running stabilization: #links="
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401 | << table->size() << " #neighbors=" << numNeighbors );
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402 | stabilize_counter = 0;
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403 | stabilize_finger = ((stabilize_finger+1) % table->get_finger_table_size() );
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404 | logging_debug("Sending discovery message to my neighbors and fingers");
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405 | const NodeID& disc1 = nodeid;
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406 | const NodeID& disc2 = table->get_finger_table(stabilize_finger).get_compare().get_center();
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407 | send_discovery_to(disc1);
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408 | if (disc1 != disc2) send_discovery_to(disc2);
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409 | orphan_removal_counter++;
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410 | if (orphan_removal_counter >= 2) {
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411 | logging_info("Running orphan removal");
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412 | orphan_removal_counter = 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()) {
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416 | logging_info("Dropping orphaned link " << it->info.toString() << " to " << it->id.toString());
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417 | baseoverlay.dropLink(it->info);
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418 | it->info = LinkID::UNSPECIFIED;
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419 | }
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420 | }
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421 | }
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422 | }
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423 | logging_debug("--- chord routing information ----------------------------------");
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424 | logging_debug("predecessor: " << (table->get_predesessor()==NULL? "<none>" :
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425 | table->get_predesessor()->toString()) );
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426 | logging_debug("node_id : " << nodeid.toString() );
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427 | logging_debug("successor : " << (table->get_successor()==NULL? "<none>" :
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428 | table->get_successor()->toString()));
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429 | logging_debug("----------------------------------------------------------------");
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430 | }
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431 |
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432 | }} // namespace ariba, overlay
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