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219 lines
6.0 KiB
C++
219 lines
6.0 KiB
C++
/*
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* This file is part of OpenTTD.
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* OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
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* OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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* See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
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*/
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/**
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* @file tcp.cpp Basic functions to receive and send TCP packets.
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*/
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#include "../../stdafx.h"
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#include "../../debug.h"
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#include "tcp.h"
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#include "../../safeguards.h"
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/**
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* Construct a socket handler for a TCP connection.
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* @param s The just opened TCP connection.
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*/
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NetworkTCPSocketHandler::NetworkTCPSocketHandler(SOCKET s) :
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NetworkSocketHandler(),
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sock(s), writable(false)
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{
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}
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NetworkTCPSocketHandler::~NetworkTCPSocketHandler()
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{
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this->CloseSocket();
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}
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/**
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* Close the actual socket of the connection.
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* Please make sure CloseConnection is called before CloseSocket, as
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* otherwise not all resources might be released.
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*/
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void NetworkTCPSocketHandler::CloseSocket()
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{
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if (this->sock != INVALID_SOCKET) closesocket(this->sock);
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this->sock = INVALID_SOCKET;
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}
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/**
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* This will put this socket handler in a close state. It will not
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* actually close the OS socket; use CloseSocket for this.
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* @param error Whether we quit under an error condition or not.
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* @return new status of the connection.
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*/
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NetworkRecvStatus NetworkTCPSocketHandler::CloseConnection([[maybe_unused]] bool error)
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{
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this->MarkClosed();
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this->writable = false;
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this->packet_queue.clear();
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this->packet_recv = nullptr;
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return NETWORK_RECV_STATUS_OKAY;
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}
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/**
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* This function puts the packet in the send-queue and it is send as
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* soon as possible. This is the next tick, or maybe one tick later
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* if the OS-network-buffer is full)
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* @param packet the packet to send
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*/
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void NetworkTCPSocketHandler::SendPacket(std::unique_ptr<Packet> &&packet)
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{
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assert(packet != nullptr);
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packet->PrepareToSend();
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this->packet_queue.push_back(std::move(packet));
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}
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/**
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* Sends all the buffered packets out for this client. It stops when:
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* 1) all packets are send (queue is empty)
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* 2) the OS reports back that it can not send any more
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* data right now (full network-buffer, it happens ;))
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* 3) sending took too long
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* @param closing_down Whether we are closing down the connection.
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* @return \c true if a (part of a) packet could be sent and
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* the connection is not closed yet.
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*/
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SendPacketsState NetworkTCPSocketHandler::SendPackets(bool closing_down)
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{
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/* We can not write to this socket!! */
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if (!this->writable) return SPS_NONE_SENT;
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if (!this->IsConnected()) return SPS_CLOSED;
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while (!this->packet_queue.empty()) {
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Packet &p = *this->packet_queue.front();
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ssize_t res = p.TransferOut<int>(send, this->sock, 0);
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if (res == -1) {
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NetworkError err = NetworkError::GetLast();
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if (!err.WouldBlock()) {
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/* Something went wrong.. close client! */
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if (!closing_down) {
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Debug(net, 0, "Send failed: {}", err.AsString());
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this->CloseConnection();
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}
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return SPS_CLOSED;
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}
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return SPS_PARTLY_SENT;
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}
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if (res == 0) {
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/* Client/server has left us :( */
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if (!closing_down) this->CloseConnection();
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return SPS_CLOSED;
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}
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/* Is this packet sent? */
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if (p.RemainingBytesToTransfer() == 0) {
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/* Go to the next packet */
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this->packet_queue.pop_front();
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} else {
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return SPS_PARTLY_SENT;
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}
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}
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return SPS_ALL_SENT;
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}
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/**
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* Receives a packet for the given client
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* @return The received packet (or nullptr when it didn't receive one)
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*/
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std::unique_ptr<Packet> NetworkTCPSocketHandler::ReceivePacket()
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{
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ssize_t res;
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if (!this->IsConnected()) return nullptr;
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if (this->packet_recv == nullptr) {
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this->packet_recv = std::make_unique<Packet>(this, TCP_MTU);
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}
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Packet &p = *this->packet_recv.get();
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/* Read packet size */
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if (!p.HasPacketSizeData()) {
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while (p.RemainingBytesToTransfer() != 0) {
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res = p.TransferIn<int>(recv, this->sock, 0);
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if (res == -1) {
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NetworkError err = NetworkError::GetLast();
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if (!err.WouldBlock()) {
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/* Something went wrong... */
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if (!err.IsConnectionReset()) Debug(net, 0, "Recv failed: {}", err.AsString());
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this->CloseConnection();
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return nullptr;
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}
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/* Connection would block, so stop for now */
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return nullptr;
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}
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if (res == 0) {
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/* Client/server has left */
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this->CloseConnection();
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return nullptr;
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}
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}
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/* Parse the size in the received packet and if not valid, close the connection. */
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if (!p.ParsePacketSize()) {
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this->CloseConnection();
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return nullptr;
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}
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}
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/* Read rest of packet */
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while (p.RemainingBytesToTransfer() != 0) {
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res = p.TransferIn<int>(recv, this->sock, 0);
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if (res == -1) {
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NetworkError err = NetworkError::GetLast();
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if (!err.WouldBlock()) {
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/* Something went wrong... */
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if (!err.IsConnectionReset()) Debug(net, 0, "Recv failed: {}", err.AsString());
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this->CloseConnection();
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return nullptr;
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}
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/* Connection would block */
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return nullptr;
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}
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if (res == 0) {
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/* Client/server has left */
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this->CloseConnection();
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return nullptr;
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}
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}
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p.PrepareToRead();
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return std::move(this->packet_recv);
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}
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/**
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* Check whether this socket can send or receive something.
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* @return \c true when there is something to receive.
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* @note Sets #writable if more data can be sent.
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*/
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bool NetworkTCPSocketHandler::CanSendReceive()
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{
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assert(this->sock != INVALID_SOCKET);
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fd_set read_fd, write_fd;
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struct timeval tv;
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FD_ZERO(&read_fd);
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FD_ZERO(&write_fd);
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FD_SET(this->sock, &read_fd);
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FD_SET(this->sock, &write_fd);
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tv.tv_sec = tv.tv_usec = 0; // don't block at all.
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if (select(FD_SETSIZE, &read_fd, &write_fd, nullptr, &tv) < 0) return false;
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this->writable = !!FD_ISSET(this->sock, &write_fd);
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return FD_ISSET(this->sock, &read_fd) != 0;
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}
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