#include <PastryRoutingTable.h>
This module contains the routing table of the Chord implementation.
Public Member Functions | |
void | initializeTable (uint bitsPerDigit, double repairTimeout, const NodeHandle &owner) |
Initializes the routing table. | |
const NodeHandle & | lookupNextHop (const OverlayKey &destination) |
gets the next hop according to the Pastry routing scheme. | |
virtual const NodeHandle & | findCloserNode (const OverlayKey &destination, bool optimize=false) |
try to find a node numerically closer to a given key with the same shared prefix as the current node in the routing table. | |
void | findCloserNodes (const OverlayKey &destination, NodeVector *nodes) |
virtual const TransportAddress & | failedNode (const TransportAddress &failed) |
tells the routing table that a node has failed | |
virtual const TransportAddress & | repair (const PastryStateMessage *msg, const PastryStateMsgProximity &prox) |
attempt to repair the routing using a received REPAIR message | |
virtual void | dumpToStateMessage (PastryStateMessage *msg) const |
dump content of the table to a PastryStateMessage | |
virtual void | dumpRowToMessage (PastryRoutingRowMessage *msg, int row) const |
dump content of a single row of the routing table to a message | |
virtual void | dumpRowToMessage (PastryStateMessage *msg, int row) const |
dump content of a single row of the routing table to a state message | |
int | getLastRow () |
gets the number of rows in the routing table | |
virtual const TransportAddress & | getRandomNode (int row) |
returns a random node from the routing table | |
bool | mergeNode (const NodeHandle &node, simtime_t prox) |
merge a node in the RoutingTable | |
bool | initStateFromHandleVector (const std::vector< PastryStateMsgHandle > &handles) |
initialize table from vector of PastryStateMsgHandles with STATE messages received during JOIN phase. | |
virtual void | dumpToVector (std::vector< TransportAddress > &affected) const |
appends all routing table entries to a given vector of TransportAddresses, needed to find all Nodes to be notified after joining. | |
Public Attributes | |
uint | nodesPerRow |
Private Member Functions | |
virtual void | earlyInit (void) |
initialize watches etc. | |
void | addRow (void) |
adds a new line to the routing table | |
uint32_t | digitAt (uint n, const OverlayKey &key) const |
returns n'th pastry digit from a key | |
const PastryExtendedNode & | nodeAt (uint row, uint col) const |
returns routing table entry at specified position | |
void | findNextNodeToAsk (PRTTrackRepair &track) const |
helper function, updates a PRTTrackRepair structure to point to the next node that can be asked for repair | |
Private Attributes | |
double | repairTimeout |
std::vector< PRTRow > | rows |
std::vector< PRTTrackRepair > | awaitingRepair |
void PastryRoutingTable::initializeTable | ( | uint | bitsPerDigit, | |
double | repairTimeout, | |||
const NodeHandle & | owner | |||
) |
Initializes the routing table.
This should be called on startup
bitsPerDigit | Pastry configuration parameter | |
repairTimeout | Pastry configuration parameter | |
owner | the node this table belongs to |
Referenced by BasePastry::baseChangeState().
00042 { 00043 this->owner = owner; 00044 this->repairTimeout = repairTimeout; 00045 this->bitsPerDigit = bitsPerDigit; 00046 nodesPerRow = 1 << bitsPerDigit; // 2 ^ bitsPerDigit 00047 00048 // forget old routing table contents in case of restart: 00049 if (!rows.empty()) rows.clear(); 00050 00051 // clear pending repair requests: 00052 if (!awaitingRepair.empty()) awaitingRepair.clear(); 00053 00054 // Create first row in table: 00055 addRow(); 00056 }
const NodeHandle & PastryRoutingTable::lookupNextHop | ( | const OverlayKey & | destination | ) |
gets the next hop according to the Pastry routing scheme.
destination | the destination key |
Referenced by BasePastry::findNode().
00067 { 00068 if (destination == owner.key) opp_error("trying to lookup own key!"); 00069 00070 uint shl = owner.key.sharedPrefixLength(destination) / bitsPerDigit; 00071 uint digit = digitAt(shl, destination); 00072 00073 if (shl >= rows.size()) { 00074 EV << "Pastry: Unable to find next hop for " << destination 00075 << ", row is empty." << endl; 00076 return NodeHandle::UNSPECIFIED_NODE; 00077 } 00078 00079 const PastryExtendedNode& next = nodeAt(shl, digit); 00080 00081 if (next.node.isUnspecified()) { 00082 EV << "Pastry: Unable to find next hop for " << destination << 00083 ", routing table entry is empty." << endl; 00084 } 00085 return next.node; 00086 }
const NodeHandle & PastryRoutingTable::findCloserNode | ( | const OverlayKey & | destination, | |
bool | optimize = false | |||
) | [virtual] |
try to find a node numerically closer to a given key with the same shared prefix as the current node in the routing table.
this method is to be called, when a regular next hop couldn't be found or wasn't reachable.
destination | the destination key | |
optimize | if set, check all nodes and return the best/closest one |
Implements PastryStateObject.
Referenced by BasePastry::findNode().
00090 { 00091 if (destination == owner.key) 00092 opp_error("trying to find closer node to own key!"); 00093 00094 const PastryExtendedNode* entry; 00095 00096 if (optimize) { 00097 // pointer to later return value, initialize to unspecified, so 00098 // the specialCloserCondition() check will be done against our own 00099 // node as long as no node closer to the destination than our own was 00100 // found. 00101 const NodeHandle* ret = &NodeHandle::UNSPECIFIED_NODE; 00102 00103 // a numerically closer node can only be found in the row containing 00104 // nodes with the same prefix length and in the row above. 00105 int shl = owner.key.sharedPrefixLength(destination) / bitsPerDigit; 00106 int digit = digitAt(shl, destination); 00107 int x = digitAt(shl, owner.key); // position index of own node 00108 00109 // first try the row with same prefix length: 00110 int n = nodesPerRow; 00111 int a = digit - 1; // position index of search to the left 00112 int b = digit + 1; // position index of search to the right 00113 00114 while ((a >= 0) || (b < n)) { 00115 // no need to continue search in one direction when own entry is 00116 // reached: 00117 if (a == x) a = -1; 00118 if (b == x) b = n; 00119 00120 if (a >= 0) { 00121 entry = &(nodeAt(shl, a)); 00122 if ((!entry->node.isUnspecified()) && 00123 specialCloserCondition(entry->node, destination, *ret)) 00124 ret = &(entry->node); 00125 a--; 00126 } 00127 if (b < n) { 00128 entry = &(nodeAt(shl, b)); 00129 if ((!entry->node.isUnspecified()) && 00130 specialCloserCondition(entry->node, destination, *ret)) 00131 ret = &(entry->node); 00132 b++; 00133 } 00134 } 00135 00136 // it this was not the first row, two more nodes to check: 00137 if (shl != 0) { 00138 // go up one row: 00139 x = digitAt(--shl, owner.key); 00140 00141 if (destination < owner.key) { 00142 entry = &(nodeAt(shl, digit - 1)); 00143 if ((!entry->node.isUnspecified()) && 00144 specialCloserCondition(entry->node, destination, *ret)) 00145 ret = &(entry->node); 00146 } else { 00147 entry = &(nodeAt(shl, digit + 1)); 00148 if ((!entry->node.isUnspecified()) && 00149 specialCloserCondition(entry->node, destination, *ret)) 00150 ret = &(entry->node); 00151 } 00152 } 00153 00154 return *ret; // still unspecified if no closer node was found 00155 } else { 00156 // no optimization, return the first closer node found 00157 for (uint y = 0; y < rows.size(); ++y) { 00158 for (uint x = 0; x < nodesPerRow; ++x) { 00159 entry = &(nodeAt(y, x)); 00160 if ((!entry->node.isUnspecified()) && 00161 specialCloserCondition(entry->node, destination)) 00162 return entry->node; 00163 } 00164 } 00165 00166 return NodeHandle::UNSPECIFIED_NODE; 00167 } 00168 }
void PastryRoutingTable::findCloserNodes | ( | const OverlayKey & | destination, | |
NodeVector * | nodes | |||
) | [virtual] |
Implements PastryStateObject.
Referenced by BasePastry::findNode().
00172 { 00173 //TODO 00174 const PastryExtendedNode* entry; 00175 00176 for (uint y = 0; y < rows.size(); ++y) { 00177 for (uint x = 0; x < nodesPerRow; ++x) { 00178 entry = &(nodeAt(y, x)); 00179 if (!entry->node.isUnspecified() 00180 /* && specialCloserCondition(entry->node, destination)*/) 00181 nodes->add(entry->node); 00182 } 00183 } 00184 }
const TransportAddress & PastryRoutingTable::failedNode | ( | const TransportAddress & | failed | ) | [virtual] |
tells the routing table that a node has failed
failed | the failed node |
Implements PastryStateObject.
Referenced by Pastry::handleFailedNode(), and Bamboo::handleFailedNode().
00333 { 00334 std::vector<PRTRow>::iterator itRows; 00335 PRTRow::iterator itCols; 00336 PRTTrackRepair tmpTrack; 00337 00338 bool found = false; 00339 00340 // find node in table: 00341 for (itRows = rows.begin(); itRows != rows.end(); itRows++) { 00342 for (itCols = itRows->begin(); itCols != itRows->end(); itCols++) { 00343 if ((! itCols->node.isUnspecified()) && 00344 (itCols->node.ip == failed.ip)) { 00345 itCols->node = NodeHandle::UNSPECIFIED_NODE; 00346 itCols->rtt = PASTRY_PROX_UNDEF; 00347 found = true; 00348 break; 00349 } 00350 } 00351 if (found) break; 00352 } 00353 00354 // not found, nothing to do: 00355 if (!found) return TransportAddress::UNSPECIFIED_NODE; 00356 00357 // else fill temporary record: 00358 tmpTrack.failedRow = itRows - rows.begin(); 00359 tmpTrack.failedCol = itCols - itRows->begin(); 00360 tmpTrack.node = TransportAddress::UNSPECIFIED_NODE; 00361 findNextNodeToAsk(tmpTrack); 00362 tmpTrack.timestamp = simTime(); 00363 00364 if (tmpTrack.node.isUnspecified()) 00365 return TransportAddress::UNSPECIFIED_NODE; 00366 awaitingRepair.push_back(tmpTrack); 00367 return awaitingRepair.back().node; 00368 }
const TransportAddress & PastryRoutingTable::repair | ( | const PastryStateMessage * | msg, | |
const PastryStateMsgProximity & | prox | |||
) | [virtual] |
attempt to repair the routing using a received REPAIR message
msg | the state message of type REPAIR | |
prox | record of proximity values matching the state message |
Reimplemented from PastryStateObject.
Referenced by Pastry::checkProxCache().
00372 { 00373 std::vector<PRTTrackRepair>::iterator it; 00374 simtime_t now = simTime(); 00375 00376 // first eliminate outdated entries in awaitingRepair: 00377 for (it = awaitingRepair.begin(); it != awaitingRepair.end();) { 00378 if (it->timestamp < (now - repairTimeout)) 00379 it = awaitingRepair.erase(it); 00380 else it++; 00381 } 00382 00383 // don't expect any more repair messages: 00384 if (awaitingRepair.empty()) return TransportAddress::UNSPECIFIED_NODE; 00385 00386 // look for source node in our list: 00387 for (it = awaitingRepair.begin(); it != awaitingRepair.end(); it++) 00388 if (it->node == msg->getSender()) break; 00389 00390 // if not found, return from function: 00391 if (it == awaitingRepair.end()) return TransportAddress::UNSPECIFIED_NODE; 00392 00393 // merge state: 00394 mergeState(msg, prox); 00395 00396 // repair not yet done? 00397 if (nodeAt(it->failedRow, it->failedCol).node.isUnspecified()) { 00398 // ask next node 00399 findNextNodeToAsk(*it); 00400 if (it->node.isUnspecified()) { 00401 // no more nodes to ask, give up: 00402 EV << "Pastry: RoutingTable giving up repair attempt." << endl; 00403 awaitingRepair.erase(it); 00404 return TransportAddress::UNSPECIFIED_NODE; 00405 } 00406 else return it->node; 00407 } 00408 00409 // repair done: clean up 00410 EV << "Pastry: RoutingTable repair was successful." << endl; 00411 awaitingRepair.erase(it); 00412 return TransportAddress::UNSPECIFIED_NODE; 00413 }
void PastryRoutingTable::dumpToStateMessage | ( | PastryStateMessage * | msg | ) | const [virtual] |
dump content of the table to a PastryStateMessage
msg | the PastryStateMessage to be filled with entries |
Implements PastryStateObject.
Referenced by BasePastry::sendStateTables().
00187 { 00188 uint i = 0; 00189 std::vector<PRTRow>::const_iterator itRows; 00190 PRTRow::const_iterator itCols; 00191 00192 msg->setRoutingTableArraySize(rows.size() * nodesPerRow); 00193 00194 for (itRows = rows.begin(); itRows != rows.end(); itRows++) 00195 for (itCols = itRows->begin(); itCols != itRows->end(); itCols++) 00196 msg->setRoutingTable(i++, itCols->node); 00197 }
void PastryRoutingTable::dumpRowToMessage | ( | PastryRoutingRowMessage * | msg, | |
int | row | |||
) | const [virtual] |
dump content of a single row of the routing table to a message
msg | the message to be filled with entries | |
row | the number of the row |
Referenced by BasePastry::sendRoutingRow().
00200 { 00201 uint i = 0; 00202 std::vector<PRTRow>::const_iterator itRows; 00203 PRTRow::const_iterator itCols; 00204 00205 msg->setRoutingTableArraySize(nodesPerRow); 00206 if (row == -1) 00207 itRows = rows.end() - 1; 00208 else if (row > (int)rows.size()) { 00209 EV << "asked for nonexistent row"; 00210 return; 00211 } 00212 else itRows = rows.begin() + row - 1; 00213 for (itCols = itRows->begin(); itCols != itRows->end(); itCols++) 00214 msg->setRoutingTable(i++, itCols->node); 00215 }
void PastryRoutingTable::dumpRowToMessage | ( | PastryStateMessage * | msg, | |
int | row | |||
) | const [virtual] |
dump content of a single row of the routing table to a state message
msg | the state message to be filled with entries | |
row | the number of the row |
00219 { 00220 uint i = 0; 00221 std::vector<PRTRow>::const_iterator itRows; 00222 PRTRow::const_iterator itCols; 00223 00224 msg->setRoutingTableArraySize(nodesPerRow); 00225 if ((row == -1) || (row > (int)rows.size())) 00226 itRows = rows.end() - 1; 00227 else if (row > (int)rows.size()) { 00228 EV << "asked for nonexistent row"; 00229 return; 00230 } 00231 else itRows = rows.begin() + row - 1; 00232 for (itCols = itRows->begin(); itCols != itRows->end(); itCols++) 00233 msg->setRoutingTable(i++, itCols->node); 00234 }
int PastryRoutingTable::getLastRow | ( | ) |
gets the number of rows in the routing table
Referenced by BasePastry::doRoutingTableMaintenance(), Pastry::handleUDPMessage(), and Bamboo::handleUDPMessage().
00237 { 00238 return rows.size(); 00239 }
const TransportAddress & PastryRoutingTable::getRandomNode | ( | int | row | ) | [virtual] |
returns a random node from the routing table
row | the row to choose a random node from |
Referenced by BasePastry::doRoutingTableMaintenance().
00242 { 00243 std::vector<PRTRow>::const_iterator itRows; 00244 PRTRow::const_iterator itCols; 00245 uint rnd; 00246 00247 itRows = rows.begin() + row; 00248 if (itRows >= rows.end()) { 00249 EV << "tried to get random Node from nonexistent row"; 00250 return TransportAddress::UNSPECIFIED_NODE; 00251 } 00252 rnd = intuniform(0, nodesPerRow - 1, 0); 00253 itCols = itRows->begin() + rnd; 00254 while (itCols != itRows->end()) { 00255 if (!itCols->node.isUnspecified()) return itCols->node; 00256 else itCols++; 00257 } 00258 return TransportAddress::UNSPECIFIED_NODE; 00259 }
bool PastryRoutingTable::mergeNode | ( | const NodeHandle & | node, | |
simtime_t | prox | |||
) | [virtual] |
merge a node in the RoutingTable
node | the node to merge | |
prox | proximity value of the node |
Implements PastryStateObject.
00262 { 00263 if (node.key == owner.key) 00264 opp_error("trying to merge node with same key!"); 00265 00266 uint shl; 00267 uint digit; 00268 PRTRow::iterator position; 00269 00270 shl = owner.key.sharedPrefixLength(node.key) / bitsPerDigit; 00271 digit = digitAt(shl, node.key); 00272 00273 while (rows.size() <= shl) addRow(); 00274 position = (rows.begin() + shl)->begin() + digit; 00275 if (position->node.isUnspecified() || (prox < position->rtt)) { 00276 EV << "Pastry: Node " << owner.key << endl; 00277 EV << " placing node " << node.key << "in row " 00278 << shl << ", col" << digit << endl; 00279 if (! position->node.isUnspecified()) { 00280 EV << " (replaced because of better proximity: " 00281 << prox << " < " << position->rtt << ")" << endl; 00282 } 00283 position->node = node; 00284 position->rtt = prox; 00285 return true; 00286 } 00287 return false; 00288 }
bool PastryRoutingTable::initStateFromHandleVector | ( | const std::vector< PastryStateMsgHandle > & | handles | ) |
initialize table from vector of PastryStateMsgHandles with STATE messages received during JOIN phase.
The vector has to be sorted by JoinHopCount of the messages
handles | the vector of PastryStateMsgHandles |
Referenced by Pastry::checkProxCache().
00291 { 00292 std::vector<PastryStateMsgHandle>::const_iterator it; 00293 int hopCheck = 0; 00294 00295 for (it = handles.begin(); it != handles.end(); ++it) { 00296 if (it->msg->getJoinHopCount() != ++hopCheck) return false; 00297 mergeState(it->msg, *(it->prox)); 00298 } 00299 return true; 00300 }
void PastryRoutingTable::dumpToVector | ( | std::vector< TransportAddress > & | affected | ) | const [virtual] |
appends all routing table entries to a given vector of TransportAddresses, needed to find all Nodes to be notified after joining.
affected | the vector to fill with routing table entries |
Implements PastryStateObject.
Referenced by Pastry::changeState(), and Pastry::doSecondStage().
00304 { 00305 std::vector<PRTRow>::const_iterator itRows; 00306 PRTRow::const_iterator itCols; 00307 00308 for (itRows = rows.begin(); itRows != rows.end(); itRows++) 00309 for (itCols = itRows->begin(); itCols != itRows->end(); itCols++) 00310 if (!itCols->node.isUnspecified()) 00311 affected.push_back(itCols->node); 00312 }
void PastryRoutingTable::earlyInit | ( | void | ) | [private, virtual] |
void PastryRoutingTable::addRow | ( | void | ) | [private] |
adds a new line to the routing table
Referenced by initializeTable(), and mergeNode().
00315 { 00316 PRTRow row(nodesPerRow, unspecNode); 00317 00318 // place own node at correct position: 00319 (row.begin() + digitAt(rows.size(), owner.key))->node = owner; 00320 rows.push_back(row); 00321 }
uint32_t PastryRoutingTable::digitAt | ( | uint | n, | |
const OverlayKey & | key | |||
) | const [private] |
returns n'th pastry digit from a key
n | which digit to return | |
key | extract digit from this key |
Referenced by addRow(), findCloserNode(), lookupNextHop(), and mergeNode().
00030 { 00031 return key.getBitRange(OverlayKey::getLength() - ++n * bitsPerDigit, bitsPerDigit); 00032 }
const PastryExtendedNode & PastryRoutingTable::nodeAt | ( | uint | row, | |
uint | col | |||
) | const [private] |
returns routing table entry at specified position
row | the number of the row | |
col | the number of the column |
Referenced by findCloserNode(), findCloserNodes(), findNextNodeToAsk(), lookupNextHop(), and repair().
00059 { 00060 if (rows.size() <= row) return unspecNode; 00061 if (col >= nodesPerRow) return unspecNode; 00062 00063 return *((rows.begin()+row)->begin()+col); 00064 }
void PastryRoutingTable::findNextNodeToAsk | ( | PRTTrackRepair & | track | ) | const [private] |
helper function, updates a PRTTrackRepair structure to point to the next node that can be asked for repair
track | the PRTTrackRepair structure |
Referenced by failedNode(), and repair().
00416 { 00417 const TransportAddress* ask; 00418 00419 if (track.node.isUnspecified()) { 00420 track.askedRow = track.failedRow; 00421 if (track.failedCol == 0) 00422 track.askedCol = 1; 00423 else 00424 track.askedCol = 0; 00425 ask = static_cast<const TransportAddress*>( 00426 &(nodeAt(track.askedRow, track.askedCol).node)); 00427 track.node = *ask; 00428 if ( (! track.node.isUnspecified()) && 00429 (track.node != owner) ) 00430 return; 00431 } 00432 00433 do { 00434 // point to next possible position in routing table: 00435 track.askedCol++; 00436 if ((track.askedRow == track.failedRow) && 00437 (track.askedCol == track.failedCol)) track.askedCol++; 00438 if (track.askedCol == nodesPerRow) { 00439 if ((track.askedRow > track.askedCol) || 00440 (track.askedRow == (rows.size() - 1))) { 00441 // no more nodes that could be asked, give up: 00442 track.node = TransportAddress::UNSPECIFIED_NODE; 00443 return; 00444 } 00445 track.askedRow++; 00446 track.askedCol = 0; 00447 } 00448 00449 ask = static_cast<const TransportAddress*>( 00450 &(nodeAt(track.askedRow, track.askedCol).node)); 00451 00452 // if (!ask->isUnspecified() && !track.node.isUnspecified() && track.node == *ask) 00453 // std::cout << "burp! " << owner.key << " " << (static_cast<const NodeHandle*>(ask))->key << "\n(" 00454 // << track.failedRow << ", " << track.failedCol << ") -> (" 00455 // << track.askedRow << ", " << track.askedCol << ")" 00456 // << std::endl; 00457 00458 if (track.node.isUnspecified() || 00459 (!ask->isUnspecified() && track.node != *ask)) 00460 track.node = *ask; //only happens if track.node == owner 00461 else track.node = TransportAddress::UNSPECIFIED_NODE; 00462 } 00463 while (track.node.isUnspecified() || (track.node == owner) ); 00464 }
double PastryRoutingTable::repairTimeout [private] |
Referenced by repair().
std::vector<PRTRow> PastryRoutingTable::rows [private] |
std::vector<PRTTrackRepair> PastryRoutingTable::awaitingRepair [private] |
Referenced by failedNode(), initializeTable(), and repair().