+++ /dev/null
-/* Copyright (c) 2010-2018. The SimGrid Team. All rights reserved. */
-
-/* This program is free software; you can redistribute it and/or modify it
- * under the terms of the license (GNU LGPL) which comes with this package. */
-
-#include "s4u-dht-chord.hpp"
-
-XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(s4u_chord);
-
-/* Returns whether an id belongs to the interval [start, end].
- *
- * The parameters are normalized to make sure they are between 0 and nb_keys - 1).
- * 1 belongs to [62, 3]
- * 1 does not belong to [3, 62]
- * 63 belongs to [62, 3]
- * 63 does not belong to [3, 62]
- * 24 belongs to [21, 29]
- * 24 does not belong to [29, 21]
- *
- * @param id id to check
- * @param start lower bound
- * @param end upper bound
- * @return a non-zero value if id in in [start, end]
- */
-static int is_in_interval(int id, int start, int end)
-{
- int i = id % nb_keys;
- int s = start % nb_keys;
- int e = end % nb_keys;
-
- // make sure end >= start and id >= start
- if (e < s) {
- e += nb_keys;
- }
-
- if (i < s) {
- i += nb_keys;
- }
-
- return i <= e;
-}
-
-void ChordMessage::destroy(void* message)
-{
- delete static_cast<ChordMessage*>(message);
-}
-
-/* Initializes the current node as the first one of the system */
-Node::Node(std::vector<std::string> args)
-{
- xbt_assert(args.size() == 3 || args.size() == 5, "Wrong number of arguments for this node");
-
- // initialize my node
- id_ = std::stoi(args[1]);
- stream = simgrid::s4u::this_actor::get_host()->extension<HostChord>()->getStream();
- mailbox_ = simgrid::s4u::Mailbox::by_name(std::to_string(id_));
- next_finger_to_fix = 0;
- fingers_ = new int[nb_bits];
-
- for (int i = 0; i < nb_bits; i++) {
- fingers_[i] = id_;
- }
-
- if (args.size() == 3) { // first ring
- deadline_ = std::stod(args[2]);
- start_time_ = simgrid::s4u::Engine::get_clock();
- XBT_DEBUG("Create a new Chord ring...");
- } else {
- known_id_ = std::stoi(args[2]);
- start_time_ = std::stod(args[3]);
- deadline_ = std::stod(args[4]);
- XBT_DEBUG("Hey! Let's join the system in %f seconds (shall leave at time %f)", start_time_,
- start_time_ + deadline_);
- }
-}
-
-Node::~Node()
-{
- delete[] fingers_;
-}
-/* Makes the current node join the ring, knowing the id of a node already in the ring
- *
- * @param known_id id of a node already in the ring
- * @return true if the join operation succeeded
- * */
-
-void Node::join(int known_id)
-{
- XBT_INFO("Joining the ring with id %d, knowing node %d", id_, known_id);
- setPredecessor(-1); // no predecessor (yet)
-
- int successor_id = remoteFindSuccessor(known_id, id_);
- if (successor_id == -1) {
- XBT_INFO("Cannot join the ring.");
- } else {
- setFinger(0, successor_id);
- printFingerTable();
- joined = true;
- }
-}
-
-/* Makes the current node quit the system */
-void Node::leave()
-{
- XBT_INFO("Well Guys! I Think it's time for me to leave ;)");
- notifyAndQuit();
- joined = false;
-}
-
-/* Notifies the successor and the predecessor of the current node before leaving */
-void Node::notifyAndQuit()
-{
- // send the PREDECESSOR_LEAVING to our successor
- ChordMessage* pred_msg = new ChordMessage(PREDECESSOR_LEAVING);
- pred_msg->request_id = pred_id_;
- pred_msg->answer_to = mailbox_;
-
- XBT_DEBUG("Sending a 'PREDECESSOR_LEAVING' to my successor %d", fingers_[0]);
- try {
- simgrid::s4u::Mailbox::by_name(std::to_string(fingers_[0]))->put(pred_msg, 10, timeout);
- } catch (simgrid::TimeoutError& e) {
- XBT_DEBUG("Timeout expired when sending a 'PREDECESSOR_LEAVING' to my successor %d", fingers_[0]);
- delete pred_msg;
- }
-
- if (pred_id_ != -1 && pred_id_ != id_) {
- // send the SUCCESSOR_LEAVING to our predecessor (only if I have one that is not me)
- ChordMessage* succ_msg = new ChordMessage(SUCCESSOR_LEAVING);
- succ_msg->request_id = fingers_[0];
- succ_msg->answer_to = mailbox_;
- XBT_DEBUG("Sending a 'SUCCESSOR_LEAVING' to my predecessor %d", pred_id_);
-
- try {
- simgrid::s4u::Mailbox::by_name(std::to_string(pred_id_))->put(succ_msg, 10, timeout);
- } catch (simgrid::TimeoutError& e) {
- XBT_DEBUG("Timeout expired when sending a 'SUCCESSOR_LEAVING' to my predecessor %d", pred_id_);
- delete succ_msg;
- }
- }
-}
-
-/* Performs a find successor request to a random id */
-void Node::randomLookup()
-{
- int res = id_;
- int random_index = RngStream_RandInt(stream, 0, nb_bits - 1);
- int random_id = fingers_[random_index];
- XBT_DEBUG("Making a lookup request for id %d", random_id);
- if (random_id != id_)
- res = findSuccessor(random_id);
- XBT_DEBUG("The successor of node %d is %d", random_id, res);
-}
-
-/* Sets a finger of the current node.
- *
- * @param node the current node
- * @param finger_index index of the finger to set (0 to nb_bits - 1)
- * @param id the id to set for this finger
- */
-void Node::setFinger(int finger_index, int id)
-{
- if (id != fingers_[finger_index]) {
- fingers_[finger_index] = id;
- XBT_VERB("My new finger #%d is %d", finger_index, id);
- }
-}
-
-/* Sets the predecessor of the current node.
- * @param id the id to predecessor, or -1 to unset the predecessor
- */
-void Node::setPredecessor(int predecessor_id)
-{
- if (predecessor_id != pred_id_) {
- pred_id_ = predecessor_id;
- XBT_VERB("My new predecessor is %d", predecessor_id);
- }
-}
-
-/** refreshes the finger table of the current node (called periodically) */
-void Node::fixFingers()
-{
- XBT_DEBUG("Fixing fingers");
- int id = findSuccessor(id_ + (1U << next_finger_to_fix));
- if (id != -1) {
- if (id != fingers_[next_finger_to_fix]) {
- setFinger(next_finger_to_fix, id);
- printFingerTable();
- }
- next_finger_to_fix = (next_finger_to_fix + 1) % nb_bits;
- }
-}
-
-/** Displays the finger table of a node. */
-void Node::printFingerTable()
-{
- if (XBT_LOG_ISENABLED(s4u_chord, xbt_log_priority_verbose)) {
- XBT_VERB("My finger table:");
- XBT_VERB("Start | Succ");
- for (int i = 0; i < nb_bits; i++) {
- XBT_VERB(" %3u | %3d", (id_ + (1U << i)) % nb_keys, fingers_[i]);
- }
-
- XBT_VERB("Predecessor: %d", pred_id_);
- }
-}
-
-/* checks whether the predecessor has failed (called periodically) */
-void Node::checkPredecessor()
-{
- XBT_DEBUG("Checking whether my predecessor is alive");
- void* data = nullptr;
- if (pred_id_ == -1)
- return;
-
- simgrid::s4u::MailboxPtr mailbox = simgrid::s4u::Mailbox::by_name(std::to_string(pred_id_));
- simgrid::s4u::MailboxPtr return_mailbox = simgrid::s4u::Mailbox::by_name(std::to_string(id_) + "_is_alive");
-
- ChordMessage* message = new ChordMessage(PREDECESSOR_ALIVE);
- message->request_id = pred_id_;
- message->answer_to = return_mailbox;
-
- XBT_DEBUG("Sending a 'Predecessor Alive' request to my predecessor %d", pred_id_);
- try {
- mailbox->put(message, 10, timeout);
- } catch (simgrid::TimeoutError& e) {
- XBT_DEBUG("Failed to send the 'Predecessor Alive' request to %d", pred_id_);
- delete message;
- return;
- }
-
- // receive the answer
- XBT_DEBUG("Sent 'Predecessor Alive' request to %d, waiting for the answer on my mailbox '%s'", pred_id_,
- message->answer_to->get_cname());
- simgrid::s4u::CommPtr comm = return_mailbox->get_async(&data);
-
- try {
- comm->wait_for(timeout);
- XBT_DEBUG("Received the answer to my 'Predecessor Alive': my predecessor %d is alive", pred_id_);
- delete static_cast<ChordMessage*>(data);
- } catch (simgrid::TimeoutError& e) {
- XBT_DEBUG("Failed to receive the answer to my 'Predecessor Alive' request");
- pred_id_ = -1;
- }
-}
-
-/* Asks its predecessor to a remote node
- *
- * @param ask_to the node to ask to
- * @return the id of its predecessor node, or -1 if the request failed (or if the node does not know its predecessor)
- */
-int Node::remoteGetPredecessor(int ask_to)
-{
- int predecessor_id = -1;
- void* data = nullptr;
- simgrid::s4u::MailboxPtr mailbox = simgrid::s4u::Mailbox::by_name(std::to_string(ask_to));
- simgrid::s4u::MailboxPtr return_mailbox = simgrid::s4u::Mailbox::by_name(std::to_string(id_) + "_pred");
-
- ChordMessage* message = new ChordMessage(GET_PREDECESSOR);
- message->request_id = id_;
- message->answer_to = return_mailbox;
-
- // send a "Get Predecessor" request to ask_to_id
- XBT_DEBUG("Sending a 'Get Predecessor' request to %d", ask_to);
- try {
- mailbox->put(message, 10, timeout);
- } catch (simgrid::TimeoutError& e) {
- XBT_DEBUG("Failed to send the 'Get Predecessor' request to %d", ask_to);
- delete message;
- return predecessor_id;
- }
-
- // receive the answer
- XBT_DEBUG("Sent 'Get Predecessor' request to %d, waiting for the answer on my mailbox '%s'", ask_to,
- message->answer_to->get_cname());
- simgrid::s4u::CommPtr comm = return_mailbox->get_async(&data);
-
- try {
- comm->wait_for(timeout);
- ChordMessage* answer = static_cast<ChordMessage*>(data);
- XBT_DEBUG("Received the answer to my 'Get Predecessor' request: the predecessor of node %d is %d", ask_to,
- answer->answer_id);
- predecessor_id = answer->answer_id;
- delete answer;
- } catch (simgrid::TimeoutError& e) {
- XBT_DEBUG("Failed to receive the answer to my 'Get Predecessor' request");
- delete static_cast<ChordMessage*>(data);
- }
-
- return predecessor_id;
-}
-
-/* Returns the closest preceding finger of an id with respect to the finger table of the current node.
- *
- * @param id the id to find
- * @return the closest preceding finger of that id
- */
-int Node::closestPrecedingFinger(int id)
-{
- for (int i = nb_bits - 1; i >= 0; i--) {
- if (is_in_interval(fingers_[i], id_ + 1, id - 1)) {
- return fingers_[i];
- }
- }
- return id_;
-}
-
-/* Makes the current node find the successor node of an id.
- *
- * @param id the id to find
- * @return the id of the successor node, or -1 if the request failed
- */
-int Node::findSuccessor(int id)
-{
- // is my successor the successor?
- if (is_in_interval(id, id_ + 1, fingers_[0])) {
- return fingers_[0];
- }
-
- // otherwise, ask the closest preceding finger in my table
- return remoteFindSuccessor(closestPrecedingFinger(id), id);
-}
-
-int Node::remoteFindSuccessor(int ask_to, int id)
-{
- int successor = -1;
- void* data = nullptr;
- simgrid::s4u::MailboxPtr mailbox = simgrid::s4u::Mailbox::by_name(std::to_string(ask_to));
- simgrid::s4u::MailboxPtr return_mailbox = simgrid::s4u::Mailbox::by_name(std::to_string(id_) + "_succ");
-
- ChordMessage* message = new ChordMessage(FIND_SUCCESSOR);
- message->request_id = id_;
- message->answer_to = return_mailbox;
-
- // send a "Find Successor" request to ask_to_id
- XBT_DEBUG("Sending a 'Find Successor' request to %d for id %d", ask_to, id);
- try {
- mailbox->put(message, 10, timeout);
- } catch (simgrid::TimeoutError& e) {
- XBT_DEBUG("Failed to send the 'Find Successor' request to %d for id %d", ask_to, id_);
- delete message;
- return successor;
- }
- // receive the answer
- XBT_DEBUG("Sent a 'Find Successor' request to %d for key %d, waiting for the answer", ask_to, id);
- simgrid::s4u::CommPtr comm = return_mailbox->get_async(&data);
-
- try {
- comm->wait_for(timeout);
- ChordMessage* answer = static_cast<ChordMessage*>(data);
- XBT_DEBUG("Received the answer to my 'Find Successor' request for id %d: the successor of key %d is %d",
- answer->request_id, id_, answer->answer_id);
- successor = answer->answer_id;
- delete answer;
- } catch (simgrid::TimeoutError& e) {
- XBT_DEBUG("Failed to receive the answer to my 'Find Successor' request");
- delete static_cast<ChordMessage*>(data);
- }
-
- return successor;
-}
-
-/* Notifies the current node that its predecessor may have changed. */
-void Node::notify(int predecessor_candidate_id)
-{
- if (pred_id_ == -1 || is_in_interval(predecessor_candidate_id, pred_id_ + 1, id_ - 1)) {
- setPredecessor(predecessor_candidate_id);
- printFingerTable();
- } else {
- XBT_DEBUG("I don't have to change my predecessor to %d", predecessor_candidate_id);
- }
-}
-
-/* Notifies a remote node that its predecessor may have changed. */
-void Node::remoteNotify(int notify_id, int predecessor_candidate_id)
-{
- ChordMessage* message = new ChordMessage(NOTIFY);
- message->request_id = predecessor_candidate_id;
- message->answer_to = nullptr;
-
- // send a "Notify" request to notify_id
- XBT_DEBUG("Sending a 'Notify' request to %d", notify_id);
- simgrid::s4u::MailboxPtr mailbox = simgrid::s4u::Mailbox::by_name(std::to_string(notify_id));
- mailbox->put_init(message, 10)->detach(ChordMessage::destroy);
-}
-
-/* This function is called periodically. It checks the immediate successor of the current node. */
-void Node::stabilize()
-{
- XBT_DEBUG("Stabilizing node");
-
- // get the predecessor of my immediate successor
- int candidate_id = pred_id_;
- int successor_id = fingers_[0];
- if (successor_id != id_)
- candidate_id = remoteGetPredecessor(successor_id);
-
- // this node is a candidate to become my new successor
- if (candidate_id != -1 && is_in_interval(candidate_id, id_ + 1, successor_id - 1)) {
- setFinger(0, candidate_id);
- }
- if (successor_id != id_) {
- remoteNotify(successor_id, id_);
- }
-}
-
-/* This function is called when a node receives a message.
- *
- * @param message the message to handle (don't touch it afterward: it will be destroyed, reused or forwarded)
- */
-void Node::handleMessage(ChordMessage* message)
-{
- switch (message->type) {
- case FIND_SUCCESSOR:
- XBT_DEBUG("Received a 'Find Successor' request from %s for id %d", message->issuer_host_name.c_str(),
- message->request_id);
- // is my successor the successor?
- if (is_in_interval(message->request_id, id_ + 1, fingers_[0])) {
- message->type = FIND_SUCCESSOR_ANSWER;
- message->answer_id = fingers_[0];
- XBT_DEBUG("Sending back a 'Find Successor Answer' to %s (mailbox %s): the successor of %d is %d",
- message->issuer_host_name.c_str(), message->answer_to->get_cname(), message->request_id,
- message->answer_id);
- message->answer_to->put_init(message, 10)->detach(ChordMessage::destroy);
- } else {
- // otherwise, forward the request to the closest preceding finger in my table
- int closest = closestPrecedingFinger(message->request_id);
- XBT_DEBUG("Forwarding the 'Find Successor' request for id %d to my closest preceding finger %d",
- message->request_id, closest);
- simgrid::s4u::MailboxPtr mailbox = simgrid::s4u::Mailbox::by_name(std::to_string(closest));
- mailbox->put_init(message, 10)->detach(ChordMessage::destroy);
- }
- break;
-
- case GET_PREDECESSOR:
- XBT_DEBUG("Receiving a 'Get Predecessor' request from %s", message->issuer_host_name.c_str());
- message->type = GET_PREDECESSOR_ANSWER;
- message->answer_id = pred_id_;
- XBT_DEBUG("Sending back a 'Get Predecessor Answer' to %s via mailbox '%s': my predecessor is %d",
- message->issuer_host_name.c_str(), message->answer_to->get_cname(), message->answer_id);
- message->answer_to->put_init(message, 10)->detach(ChordMessage::destroy);
- break;
-
- case NOTIFY:
- // someone is telling me that he may be my new predecessor
- XBT_DEBUG("Receiving a 'Notify' request from %s", message->issuer_host_name.c_str());
- notify(message->request_id);
- delete message;
- break;
-
- case PREDECESSOR_LEAVING:
- // my predecessor is about to quit
- XBT_DEBUG("Receiving a 'Predecessor Leaving' message from %s", message->issuer_host_name.c_str());
- // modify my predecessor
- setPredecessor(message->request_id);
- delete message;
- /*TODO :
- >> notify my new predecessor
- >> send a notify_predecessors !!
- */
- break;
-
- case SUCCESSOR_LEAVING:
- // my successor is about to quit
- XBT_DEBUG("Receiving a 'Successor Leaving' message from %s", message->issuer_host_name.c_str());
- // modify my successor FIXME : this should be implicit ?
- setFinger(0, message->request_id);
- delete message;
- /* TODO
- >> notify my new successor
- >> update my table & predecessors table */
- break;
-
- case PREDECESSOR_ALIVE:
- XBT_DEBUG("Receiving a 'Predecessor Alive' request from %s", message->issuer_host_name.c_str());
- message->type = PREDECESSOR_ALIVE_ANSWER;
- XBT_DEBUG("Sending back a 'Predecessor Alive Answer' to %s (mailbox %s)", message->issuer_host_name.c_str(),
- message->answer_to->get_cname());
- message->answer_to->put_init(message, 10)->detach(ChordMessage::destroy);
- break;
-
- default:
- XBT_DEBUG("Ignoring unexpected message: %d from %s", message->type, message->issuer_host_name.c_str());
- delete message;
- }
-}
