/** Selects the appropriate piece to download and requests it to the remote_peer */
void Peer::requestNewPieceTo(Connection* remote_peer)
{
int piece = selectPieceToDownload(remote_peer);
if (piece != -1) {
current_pieces |= (1U << (unsigned int)piece);
sendRequestTo(remote_peer, piece);
}
}
/*!
Send and encode a request to a specific receptor.
\sa vpNetwork::sendRequest()
\sa vpNetwork::sendAndEncodeRequest()
\sa vpNetwork::sendAndEncodeRequestTo()
\sa vpNetwork::send()
\sa vpNetwork::sendTo()
\param req : Request to send.
\param dest : Index of the receptor receiving the request.
\return The number of bytes that have been sent, -1 if an error occured.
*/
int vpNetwork::sendAndEncodeRequestTo(vpRequest &req, const unsigned int &dest)
{
req.encode();
return sendRequestTo(req,dest);
}
void Peer::handleMessage()
{
const char* type_names[10] = {"HANDSHAKE", "CHOKE", "UNCHOKE", "INTERESTED", "NOTINTERESTED",
"HAVE", "BITFIELD", "REQUEST", "PIECE", "CANCEL"};
XBT_DEBUG("Received a %s message from %s", type_names[message->type], message->return_mailbox->get_cname());
auto known_peer = connected_peers.find(message->peer_id);
Connection* remote_peer = (known_peer == connected_peers.end()) ? nullptr : known_peer->second;
xbt_assert(remote_peer != nullptr || message->type == MESSAGE_HANDSHAKE,
"The impossible did happened: A not-in-our-list peer sent us a message.");
switch (message->type) {
case MESSAGE_HANDSHAKE:
// Check if the peer is in our connection list.
if (remote_peer == nullptr) {
XBT_DEBUG("This peer %d was unknown, answer to its handshake", message->peer_id);
connected_peers[message->peer_id] = new Connection(message->peer_id);
sendMessage(message->return_mailbox, MESSAGE_HANDSHAKE, MESSAGE_HANDSHAKE_SIZE);
}
// Send our bitfield to the peer
sendBitfield(message->return_mailbox);
break;
case MESSAGE_BITFIELD:
// Update the pieces list
updatePiecesCountFromBitfield(message->bitfield);
// Store the bitfield
remote_peer->bitfield = message->bitfield;
xbt_assert(not remote_peer->am_interested, "Should not be interested at first");
if (isInterestedBy(remote_peer)) {
remote_peer->am_interested = true;
sendMessage(message->return_mailbox, MESSAGE_INTERESTED, MESSAGE_INTERESTED_SIZE);
}
break;
case MESSAGE_INTERESTED:
// Update the interested state of the peer.
remote_peer->interested = true;
updateActivePeersSet(remote_peer);
break;
case MESSAGE_NOTINTERESTED:
remote_peer->interested = false;
updateActivePeersSet(remote_peer);
break;
case MESSAGE_UNCHOKE:
xbt_assert(remote_peer->choked_download);
remote_peer->choked_download = false;
// Send requests to the peer, since it has unchoked us
if (remote_peer->am_interested)
requestNewPieceTo(remote_peer);
break;
case MESSAGE_CHOKE:
xbt_assert(not remote_peer->choked_download);
remote_peer->choked_download = true;
if (remote_peer->current_piece != -1)
removeCurrentPiece(remote_peer, remote_peer->current_piece);
break;
case MESSAGE_HAVE:
XBT_DEBUG("\t for piece %d", message->piece);
xbt_assert((message->piece >= 0 && static_cast<unsigned int>(message->piece) < FILE_PIECES),
"Wrong HAVE message received");
remote_peer->bitfield = remote_peer->bitfield | (1U << static_cast<unsigned int>(message->piece));
pieces_count[message->piece]++;
// If the piece is in our pieces, we tell the peer that we are interested.
if (not remote_peer->am_interested && hasNotPiece(message->piece)) {
remote_peer->am_interested = true;
sendMessage(message->return_mailbox, MESSAGE_INTERESTED, MESSAGE_INTERESTED_SIZE);
if (not remote_peer->choked_download)
requestNewPieceTo(remote_peer);
}
break;
case MESSAGE_REQUEST:
xbt_assert(remote_peer->interested);
xbt_assert((message->piece >= 0 && static_cast<unsigned int>(message->piece) < FILE_PIECES),
"Wrong HAVE message received");
if (not remote_peer->choked_upload) {
XBT_DEBUG("\t for piece %d (%d,%d)", message->piece, message->block_index,
message->block_index + message->block_length);
if (not hasNotPiece(message->piece)) {
sendPiece(message->return_mailbox, message->piece, message->block_index, message->block_length);
}
} else {
XBT_DEBUG("\t for piece %d but he is choked.", message->peer_id);
}
break;
case MESSAGE_PIECE:
XBT_DEBUG(" \t for piece %d (%d,%d)", message->piece, message->block_index,
message->block_index + message->block_length);
xbt_assert(not remote_peer->choked_download);
xbt_assert(remote_peer->am_interested || ENABLE_END_GAME_MODE,
"Can't received a piece if I'm not interested without end-game mode!"
"piece (%d) bitfield (%u) remote bitfield (%u)",
message->piece, bitfield_, remote_peer->bitfield);
xbt_assert(not remote_peer->choked_download, "Can't received a piece if I'm choked !");
xbt_assert((message->piece >= 0 && static_cast<unsigned int>(message->piece) < FILE_PIECES),
"Wrong piece received");
// TODO: Execute a computation.
if (hasNotPiece(static_cast<unsigned int>(message->piece))) {
updateBitfieldBlocks(message->piece, message->block_index, message->block_length);
if (hasCompletedPiece(static_cast<unsigned int>(message->piece))) {
// Removing the piece from our piece list
removeCurrentPiece(remote_peer, message->piece);
// Setting the fact that we have the piece
bitfield_ = bitfield_ | (1U << static_cast<unsigned int>(message->piece));
XBT_DEBUG("My status is now %s", getStatus().c_str());
// Sending the information to all the peers we are connected to
sendHaveToAllPeers(message->piece);
// sending UNINTERESTED to peers that do not have what we want.
updateInterestedAfterReceive();
} else { // piece not completed
sendRequestTo(remote_peer, message->piece); // ask for the next block
}
} else {
XBT_DEBUG("However, we already have it");
xbt_assert(ENABLE_END_GAME_MODE, "Should not happen because we don't use end game mode !");
requestNewPieceTo(remote_peer);
}
break;
case MESSAGE_CANCEL:
break;
default:
THROW_IMPOSSIBLE;
}
// Update the peer speed.
if (remote_peer) {
remote_peer->addSpeedValue(1.0 / (simgrid::s4u::Engine::get_clock() - begin_receive_time));
}
begin_receive_time = simgrid::s4u::Engine::get_clock();
}
/*!
Send a request to the first receptor in the list.
\sa vpNetwork::sendRequestTo()
\sa vpNetwork::sendAndEncodeRequest()
\sa vpNetwork::sendAndEncodeRequestTo()
\sa vpNetwork::send()
\sa vpNetwork::sendTo()
\param req : Request to send.
\return The number of bytes that have been sent, -1 if an error occured.
*/
int vpNetwork::sendRequest(vpRequest &req)
{
return sendRequestTo(req,0);
}