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379 lines
11 KiB
C++
379 lines
11 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_connect.cpp Basic functions to create connections without blocking.
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*/
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#include "../../stdafx.h"
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#include "../../thread.h"
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#include "tcp.h"
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#include "../network_internal.h"
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#include <deque>
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#include "../../safeguards.h"
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/** List of connections that are currently being created */
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static std::vector<TCPConnecter *> _tcp_connecters;
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/**
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* Create a new connecter for the given address
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* @param connection_string the address to connect to
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*/
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TCPConnecter::TCPConnecter(const std::string &connection_string, uint16 default_port)
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{
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this->connection_string = NormalizeConnectionString(connection_string, default_port);
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_tcp_connecters.push_back(this);
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}
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TCPConnecter::~TCPConnecter()
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{
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if (this->resolve_thread.joinable()) {
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this->resolve_thread.join();
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}
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for (const auto &socket : this->sockets) {
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closesocket(socket);
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}
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this->sockets.clear();
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this->sock_to_address.clear();
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if (this->ai != nullptr) freeaddrinfo(this->ai);
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}
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/**
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* Start a connection to the indicated address.
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* @param address The address to connection to.
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*/
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void TCPConnecter::Connect(addrinfo *address)
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{
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SOCKET sock = socket(address->ai_family, address->ai_socktype, address->ai_protocol);
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if (sock == INVALID_SOCKET) {
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DEBUG(net, 0, "Could not create %s %s socket: %s", NetworkAddress::SocketTypeAsString(address->ai_socktype), NetworkAddress::AddressFamilyAsString(address->ai_family), NetworkError::GetLast().AsString());
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return;
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}
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if (!SetNoDelay(sock)) {
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DEBUG(net, 1, "Setting TCP_NODELAY failed: %s", NetworkError::GetLast().AsString());
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}
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if (!SetNonBlocking(sock)) {
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DEBUG(net, 0, "Setting non-blocking mode failed: %s", NetworkError::GetLast().AsString());
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}
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NetworkAddress network_address = NetworkAddress(address->ai_addr, (int)address->ai_addrlen);
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DEBUG(net, 5, "Attempting to connect to %s", network_address.GetAddressAsString().c_str());
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int err = connect(sock, address->ai_addr, (int)address->ai_addrlen);
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if (err != 0 && !NetworkError::GetLast().IsConnectInProgress()) {
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closesocket(sock);
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DEBUG(net, 1, "Could not connect to %s: %s", network_address.GetAddressAsString().c_str(), NetworkError::GetLast().AsString());
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return;
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}
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this->sock_to_address[sock] = network_address;
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this->sockets.push_back(sock);
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}
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/**
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* Start the connect() for the next address in the list.
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* @return True iff a new connect() is attempted.
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*/
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bool TCPConnecter::TryNextAddress()
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{
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if (this->current_address >= this->addresses.size()) return false;
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this->last_attempt = std::chrono::steady_clock::now();
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this->Connect(this->addresses[this->current_address++]);
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return true;
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}
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/**
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* Callback when resolving is done.
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* @param ai A linked-list of address information.
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*/
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void TCPConnecter::OnResolved(addrinfo *ai)
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{
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std::deque<addrinfo *> addresses_ipv4, addresses_ipv6;
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/* Apply "Happy Eyeballs" if it is likely IPv6 is functional. */
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/* Detect if IPv6 is likely to succeed or not. */
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bool seen_ipv6 = false;
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bool resort = true;
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for (addrinfo *runp = ai; runp != nullptr; runp = runp->ai_next) {
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if (runp->ai_family == AF_INET6) {
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seen_ipv6 = true;
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} else if (!seen_ipv6) {
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/* We see an IPv4 before an IPv6; this most likely means there is
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* no IPv6 available on the system, so keep the order of this
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* list. */
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resort = false;
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break;
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}
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}
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/* Convert the addrinfo into NetworkAddresses. */
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for (addrinfo *runp = ai; runp != nullptr; runp = runp->ai_next) {
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if (resort) {
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if (runp->ai_family == AF_INET6) {
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addresses_ipv6.emplace_back(runp);
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} else {
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addresses_ipv4.emplace_back(runp);
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}
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} else {
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this->addresses.emplace_back(runp);
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}
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}
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/* If we want to resort, make the list like IPv6 / IPv4 / IPv6 / IPv4 / ..
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* for how ever many (round-robin) DNS entries we have. */
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if (resort) {
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while (!addresses_ipv4.empty() || !addresses_ipv6.empty()) {
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if (!addresses_ipv6.empty()) {
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this->addresses.push_back(addresses_ipv6.front());
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addresses_ipv6.pop_front();
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}
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if (!addresses_ipv4.empty()) {
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this->addresses.push_back(addresses_ipv4.front());
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addresses_ipv4.pop_front();
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}
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}
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}
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if (_debug_net_level >= 6) {
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DEBUG(net, 6, "%s resolved in:", this->connection_string.c_str());
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for (const auto &address : this->addresses) {
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DEBUG(net, 6, "- %s", NetworkAddress(address->ai_addr, (int)address->ai_addrlen).GetAddressAsString().c_str());
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}
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}
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this->current_address = 0;
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}
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/**
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* Start resolving the hostname.
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*
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* This function must change "status" to either Status::FAILURE
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* or Status::CONNECTING before returning.
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*/
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void TCPConnecter::Resolve()
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{
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/* Port is already guaranteed part of the connection_string. */
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NetworkAddress address = ParseConnectionString(this->connection_string, 0);
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addrinfo hints;
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memset(&hints, 0, sizeof(hints));
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hints.ai_family = AF_UNSPEC;
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hints.ai_flags = AI_ADDRCONFIG;
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hints.ai_socktype = SOCK_STREAM;
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char port_name[6];
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seprintf(port_name, lastof(port_name), "%u", address.GetPort());
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static bool getaddrinfo_timeout_error_shown = false;
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auto start = std::chrono::steady_clock::now();
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addrinfo *ai;
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int error = getaddrinfo(address.GetHostname(), port_name, &hints, &ai);
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auto end = std::chrono::steady_clock::now();
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auto duration = std::chrono::duration_cast<std::chrono::seconds>(end - start);
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if (!getaddrinfo_timeout_error_shown && duration >= std::chrono::seconds(5)) {
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DEBUG(net, 0, "getaddrinfo() for address \"%s\" took %i seconds", this->connection_string.c_str(), (int)duration.count());
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DEBUG(net, 0, " This is likely an issue in the DNS name resolver's configuration causing it to time out");
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getaddrinfo_timeout_error_shown = true;
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}
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if (error != 0) {
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DEBUG(net, 0, "Failed to resolve DNS for %s", this->connection_string.c_str());
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this->status = Status::FAILURE;
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return;
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}
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this->ai = ai;
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this->OnResolved(ai);
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this->status = Status::CONNECTING;
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}
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/**
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* Thunk to start Resolve() on the right instance.
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*/
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/* static */ void TCPConnecter::ResolveThunk(TCPConnecter *connecter)
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{
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connecter->Resolve();
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}
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/**
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* Check if there was activity for this connecter.
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* @return True iff the TCPConnecter is done and can be cleaned up.
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*/
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bool TCPConnecter::CheckActivity()
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{
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switch (this->status.load()) {
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case Status::INIT:
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/* Start the thread delayed, so the vtable is loaded. This allows classes
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* to overload functions used by Resolve() (in case threading is disabled). */
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if (StartNewThread(&this->resolve_thread, "ottd:resolve", &TCPConnecter::ResolveThunk, this)) {
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this->status = Status::RESOLVING;
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return false;
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}
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/* No threads, do a blocking resolve. */
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this->Resolve();
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/* Continue as we are either failed or can start the first
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* connection. The rest of this function handles exactly that. */
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break;
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case Status::RESOLVING:
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/* Wait till Resolve() comes back with an answer (in case it runs threaded). */
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return false;
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case Status::FAILURE:
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/* Ensure the OnFailure() is called from the game-thread instead of the
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* resolve-thread, as otherwise we can get into some threading issues. */
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this->OnFailure();
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return true;
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case Status::CONNECTING:
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break;
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}
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/* If there are no attempts pending, connect to the next. */
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if (this->sockets.empty()) {
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if (!this->TryNextAddress()) {
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/* There were no more addresses to try, so we failed. */
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this->OnFailure();
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return true;
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}
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return false;
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}
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fd_set write_fd;
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FD_ZERO(&write_fd);
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for (const auto &socket : this->sockets) {
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FD_SET(socket, &write_fd);
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}
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timeval tv;
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tv.tv_usec = 0;
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tv.tv_sec = 0;
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int n = select(FD_SETSIZE, nullptr, &write_fd, nullptr, &tv);
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/* select() failed; hopefully next try it doesn't. */
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if (n < 0) {
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/* select() normally never fails; so hopefully it works next try! */
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DEBUG(net, 1, "select() failed: %s", NetworkError::GetLast().AsString());
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return false;
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}
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/* No socket updates. */
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if (n == 0) {
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/* Wait 250ms between attempting another address. */
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if (std::chrono::steady_clock::now() < this->last_attempt + std::chrono::milliseconds(250)) return false;
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/* Try the next address in the list. */
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if (this->TryNextAddress()) return false;
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/* Wait up to 3 seconds since the last connection we started. */
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if (std::chrono::steady_clock::now() < this->last_attempt + std::chrono::milliseconds(3000)) return false;
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/* More than 3 seconds no socket reported activity, and there are no
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* more address to try. Timeout the attempt. */
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DEBUG(net, 0, "Timeout while connecting to %s", this->connection_string.c_str());
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for (const auto &socket : this->sockets) {
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closesocket(socket);
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}
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this->sockets.clear();
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this->sock_to_address.clear();
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this->OnFailure();
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return true;
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}
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/* Check for errors on any of the sockets. */
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for (auto it = this->sockets.begin(); it != this->sockets.end(); /* nothing */) {
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NetworkError socket_error = GetSocketError(*it);
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if (socket_error.HasError()) {
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DEBUG(net, 1, "Could not connect to %s: %s", this->sock_to_address[*it].GetAddressAsString().c_str(), socket_error.AsString());
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closesocket(*it);
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this->sock_to_address.erase(*it);
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it = this->sockets.erase(it);
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} else {
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it++;
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}
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}
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/* In case all sockets had an error, queue a new one. */
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if (this->sockets.empty()) {
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if (!this->TryNextAddress()) {
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/* There were no more addresses to try, so we failed. */
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this->OnFailure();
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return true;
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}
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return false;
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}
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/* At least one socket is connected. The first one that does is the one
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* we will be using, and we close all other sockets. */
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SOCKET connected_socket = INVALID_SOCKET;
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for (auto it = this->sockets.begin(); it != this->sockets.end(); /* nothing */) {
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if (connected_socket == INVALID_SOCKET && FD_ISSET(*it, &write_fd)) {
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connected_socket = *it;
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} else {
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closesocket(*it);
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}
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this->sock_to_address.erase(*it);
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it = this->sockets.erase(it);
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}
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assert(connected_socket != INVALID_SOCKET);
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DEBUG(net, 3, "Connected to %s", this->connection_string.c_str());
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if (_debug_net_level >= 5) {
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DEBUG(net, 5, "- using %s", NetworkAddress::GetPeerName(connected_socket).c_str());
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}
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this->OnConnect(connected_socket);
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return true;
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}
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/**
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* Check whether we need to call the callback, i.e. whether we
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* have connected or aborted and call the appropriate callback
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* for that. It's done this way to ease on the locking that
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* would otherwise be needed everywhere.
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*/
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/* static */ void TCPConnecter::CheckCallbacks()
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{
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for (auto iter = _tcp_connecters.begin(); iter < _tcp_connecters.end(); /* nothing */) {
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TCPConnecter *cur = *iter;
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if (cur->CheckActivity()) {
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iter = _tcp_connecters.erase(iter);
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delete cur;
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} else {
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iter++;
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}
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}
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}
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/** Kill all connection attempts. */
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/* static */ void TCPConnecter::KillAll()
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{
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for (auto iter = _tcp_connecters.begin(); iter < _tcp_connecters.end(); /* nothing */) {
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TCPConnecter *cur = *iter;
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iter = _tcp_connecters.erase(iter);
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delete cur;
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}
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}
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