OpenTTD Source: src/network/core/tcp_connect.cpp Source File

OpenTTD Source 14.1

tcp_connect.cpp
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1 /*
2 * This file is part of OpenTTD.
3 * 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.
4 * 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.
5 * 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/>.
6 */
7
12 #include "../../stdafx.h"
13 #include "../../thread.h"
14
15 #include "tcp.h"
16 #include "../network_coordinator.h"
17 #include "../network_internal.h"
18
19 #include "../../safeguards.h"
20
21 /* static */ std::vector<std::shared_ptr<TCPConnecter>> TCPConnecter::connecters;
22
29 TCPConnecter::TCPConnecter(const std::string &connection_string, uint16_t default_port, const NetworkAddress &bind_address, int family) :
30 bind_address(bind_address),
31 family(family)
32 {
33 this->connection_string = NormalizeConnectionString(connection_string, default_port);
34 }
35
41 TCPServerConnecter::TCPServerConnecter(const std::string &connection_string, uint16_t default_port) :
42 server_address(ServerAddress::Parse(connection_string, default_port))
43 {
44 switch (this->server_address.type) {
45 case SERVER_ADDRESS_DIRECT:
46 this->connection_string = this->server_address.connection_string;
47 break;
48
49 case SERVER_ADDRESS_INVITE_CODE:
50 this->status = Status::Connecting;
51 _network_coordinator_client.ConnectToServer(this->server_address.connection_string, this);
52 break;
53
54 default:
55 NOT_REACHED();
56 }
57 }
58
59 TCPConnecter::~TCPConnecter()
60 {
61 if (this->resolve_thread.joinable()) {
62 this->resolve_thread.join();
63 }
64
65 for (const auto &socket : this->sockets) {
66 closesocket(socket);
67 }
68 this->sockets.clear();
69 this->sock_to_address.clear();
70
71 if (this->ai != nullptr) freeaddrinfo(this->ai);
72 }
73
78 void TCPConnecter::Kill()
79 {
80 /* Delay the removing of the socket till the next CheckActivity(). */
81 this->killed = true;
82 }
83
88 void TCPConnecter::Connect(addrinfo *address)
89 {
90 SOCKET sock = socket(address->ai_family, address->ai_socktype, address->ai_protocol);
91 if (sock == INVALID_SOCKET) {
92 Debug(net, 0, "Could not create {} {} socket: {}", NetworkAddress::SocketTypeAsString(address->ai_socktype), NetworkAddress::AddressFamilyAsString(address->ai_family), NetworkError::GetLast().AsString());
93 return;
94 }
95
96 if (!SetReusePort(sock)) {
97 Debug(net, 0, "Setting reuse-port mode failed: {}", NetworkError::GetLast().AsString());
98 }
99
100 if (this->bind_address.GetPort() > 0) {
101 if (bind(sock, (const sockaddr *)this->bind_address.GetAddress(), this->bind_address.GetAddressLength()) != 0) {
102 Debug(net, 1, "Could not bind socket on {}: {}", this->bind_address.GetAddressAsString(), NetworkError::GetLast().AsString());
103 closesocket(sock);
104 return;
105 }
106 }
107
108 if (!SetNoDelay(sock)) {
109 Debug(net, 1, "Setting TCP_NODELAY failed: {}", NetworkError::GetLast().AsString());
110 }
111 if (!SetNonBlocking(sock)) {
112 Debug(net, 0, "Setting non-blocking mode failed: {}", NetworkError::GetLast().AsString());
113 }
114
115 NetworkAddress network_address = NetworkAddress(address->ai_addr, (int)address->ai_addrlen);
116 Debug(net, 5, "Attempting to connect to {}", network_address.GetAddressAsString());
117
118 int err = connect(sock, address->ai_addr, (int)address->ai_addrlen);
119 if (err != 0 && !NetworkError::GetLast().IsConnectInProgress()) {
120 closesocket(sock);
121
122 Debug(net, 1, "Could not connect to {}: {}", network_address.GetAddressAsString(), NetworkError::GetLast().AsString());
123 return;
124 }
125
126 this->sock_to_address[sock] = network_address;
127 this->sockets.push_back(sock);
128 }
129
134 bool TCPConnecter::TryNextAddress()
135 {
136 if (this->current_address >= this->addresses.size()) return false;
137
138 this->last_attempt = std::chrono::steady_clock::now();
139 this->Connect(this->addresses[this->current_address++]);
140
141 return true;
142 }
143
148 void TCPConnecter::OnResolved(addrinfo *ai)
149 {
150 std::deque<addrinfo *> addresses_ipv4, addresses_ipv6;
151
152 /* Apply "Happy Eyeballs" if it is likely IPv6 is functional. */
153
154 /* Detect if IPv6 is likely to succeed or not. */
155 bool seen_ipv6 = false;
156 bool resort = true;
157 for (addrinfo *runp = ai; runp != nullptr; runp = runp->ai_next) {
158 if (runp->ai_family == AF_INET6) {
159 seen_ipv6 = true;
160 } else if (!seen_ipv6) {
161 /* We see an IPv4 before an IPv6; this most likely means there is
162 * no IPv6 available on the system, so keep the order of this
163 * list. */
164 resort = false;
165 break;
166 }
167 }
168
169 /* Convert the addrinfo into NetworkAddresses. */
170 for (addrinfo *runp = ai; runp != nullptr; runp = runp->ai_next) {
171 /* Skip entries if the family is set and it is not matching. */
172 if (this->family != AF_UNSPEC && this->family != runp->ai_family) continue;
173
174 if (resort) {
175 if (runp->ai_family == AF_INET6) {
176 addresses_ipv6.emplace_back(runp);
177 } else {
178 addresses_ipv4.emplace_back(runp);
179 }
180 } else {
181 this->addresses.emplace_back(runp);
182 }
183 }
184
185 /* If we want to resort, make the list like IPv6 / IPv4 / IPv6 / IPv4 / ..
186 * for how ever many (round-robin) DNS entries we have. */
187 if (resort) {
188 while (!addresses_ipv4.empty() || !addresses_ipv6.empty()) {
189 if (!addresses_ipv6.empty()) {
190 this->addresses.push_back(addresses_ipv6.front());
191 addresses_ipv6.pop_front();
192 }
193 if (!addresses_ipv4.empty()) {
194 this->addresses.push_back(addresses_ipv4.front());
195 addresses_ipv4.pop_front();
196 }
197 }
198 }
199
200 if (_debug_net_level >= 6) {
201 if (this->addresses.empty()) {
202 Debug(net, 6, "{} did not resolve", this->connection_string);
203 } else {
204 Debug(net, 6, "{} resolved in:", this->connection_string);
205 for (const auto &address : this->addresses) {
206 Debug(net, 6, "- {}", NetworkAddress(address->ai_addr, (int)address->ai_addrlen).GetAddressAsString());
207 }
208 }
209 }
210
211 this->current_address = 0;
212 }
213
220 void TCPConnecter::Resolve()
221 {
222 /* Port is already guaranteed part of the connection_string. */
223 NetworkAddress address = ParseConnectionString(this->connection_string, 0);
224
225 addrinfo hints;
226 memset(&hints, 0, sizeof(hints));
227 hints.ai_family = AF_UNSPEC;
228 hints.ai_flags = AI_ADDRCONFIG;
229 hints.ai_socktype = SOCK_STREAM;
230
231 std::string port_name = std::to_string(address.GetPort());
232
233 static bool getaddrinfo_timeout_error_shown = false;
234 auto start = std::chrono::steady_clock::now();
235
236 addrinfo *ai;
237 int error = getaddrinfo(address.GetHostname().c_str(), port_name.c_str(), &hints, &ai);
238
239 auto end = std::chrono::steady_clock::now();
240 auto duration = std::chrono::duration_cast<std::chrono::seconds>(end - start);
241 if (!getaddrinfo_timeout_error_shown && duration >= std::chrono::seconds(5)) {
242 Debug(net, 0, "getaddrinfo() for address \"{}\" took {} seconds", this->connection_string, duration.count());
243 Debug(net, 0, " This is likely an issue in the DNS name resolver's configuration causing it to time out");
244 getaddrinfo_timeout_error_shown = true;
245 }
246
247 if (error != 0) {
248 Debug(net, 0, "Failed to resolve DNS for {}", this->connection_string);
249 this->status = Status::Failure;
250 return;
251 }
252
253 this->ai = ai;
254 this->OnResolved(ai);
255
256 this->status = Status::Connecting;
257 }
258
262 /* static */ void TCPConnecter::ResolveThunk(TCPConnecter *connecter)
263 {
264 connecter->Resolve();
265 }
266
271 bool TCPConnecter::CheckActivity()
272 {
273 if (this->killed) return true;
274
275 switch (this->status) {
276 case Status::Init:
277 /* Start the thread delayed, so the vtable is loaded. This allows classes
278 * to overload functions used by Resolve() (in case threading is disabled). */
279 if (StartNewThread(&this->resolve_thread, "ottd:resolve", &TCPConnecter::ResolveThunk, this)) {
280 this->status = Status::Resolving;
281 return false;
282 }
283
284 /* No threads, do a blocking resolve. */
285 this->Resolve();
286
287 /* Continue as we are either failed or can start the first
288 * connection. The rest of this function handles exactly that. */
289 break;
290
291 case Status::Resolving:
292 /* Wait till Resolve() comes back with an answer (in case it runs threaded). */
293 return false;
294
295 case Status::Failure:
296 /* Ensure the OnFailure() is called from the game-thread instead of the
297 * resolve-thread, as otherwise we can get into some threading issues. */
298 this->OnFailure();
299 return true;
300
301 case Status::Connecting:
302 case Status::Connected:
303 break;
304 }
305
306 /* If there are no attempts pending, connect to the next. */
307 if (this->sockets.empty()) {
308 if (!this->TryNextAddress()) {
309 /* There were no more addresses to try, so we failed. */
310 this->OnFailure();
311 return true;
312 }
313 return false;
314 }
315
316 fd_set write_fd;
317 FD_ZERO(&write_fd);
318 for (const auto &socket : this->sockets) {
319 FD_SET(socket, &write_fd);
320 }
321
322 timeval tv;
323 tv.tv_usec = 0;
324 tv.tv_sec = 0;
325 int n = select(FD_SETSIZE, nullptr, &write_fd, nullptr, &tv);
326 /* select() failed; hopefully next try it doesn't. */
327 if (n < 0) {
328 /* select() normally never fails; so hopefully it works next try! */
329 Debug(net, 1, "select() failed: {}", NetworkError::GetLast().AsString());
330 return false;
331 }
332
333 /* No socket updates. */
334 if (n == 0) {
335 /* Wait 250ms between attempting another address. */
336 if (std::chrono::steady_clock::now() < this->last_attempt + std::chrono::milliseconds(250)) return false;
337
338 /* Try the next address in the list. */
339 if (this->TryNextAddress()) return false;
340
341 /* Wait up to 3 seconds since the last connection we started. */
342 if (std::chrono::steady_clock::now() < this->last_attempt + std::chrono::milliseconds(3000)) return false;
343
344 /* More than 3 seconds no socket reported activity, and there are no
345 * more address to try. Timeout the attempt. */
346 Debug(net, 0, "Timeout while connecting to {}", this->connection_string);
347
348 for (const auto &socket : this->sockets) {
349 closesocket(socket);
350 }
351 this->sockets.clear();
352 this->sock_to_address.clear();
353
354 this->OnFailure();
355 return true;
356 }
357
358 /* If a socket is writeable, it is either in error-state or connected.
359 * Remove all sockets that are in error-state and mark the first that is
360 * not in error-state as the socket we will use for our connection. */
361 SOCKET connected_socket = INVALID_SOCKET;
362 for (auto it = this->sockets.begin(); it != this->sockets.end(); /* nothing */) {
363 NetworkError socket_error = GetSocketError(*it);
364 if (socket_error.HasError()) {
365 Debug(net, 1, "Could not connect to {}: {}", this->sock_to_address[*it].GetAddressAsString(), socket_error.AsString());
366 closesocket(*it);
367 this->sock_to_address.erase(*it);
368 it = this->sockets.erase(it);
369 continue;
370 }
371
372 /* No error but writeable means connected. */
373 if (connected_socket == INVALID_SOCKET && FD_ISSET(*it, &write_fd)) {
374 connected_socket = *it;
375 }
376
377 it++;
378 }
379
380 /* All the writable sockets were in error state. So nothing is connected yet. */
381 if (connected_socket == INVALID_SOCKET) return false;
382
383 /* Close all sockets except the one we picked for our connection. */
384 for (auto it = this->sockets.begin(); it != this->sockets.end(); /* nothing */) {
385 if (connected_socket != *it) {
386 closesocket(*it);
387 }
388 this->sock_to_address.erase(*it);
389 it = this->sockets.erase(it);
390 }
391
392 Debug(net, 3, "Connected to {}", this->connection_string);
393 if (_debug_net_level >= 5) {
394 Debug(net, 5, "- using {}", NetworkAddress::GetPeerName(connected_socket));
395 }
396
397 this->OnConnect(connected_socket);
398 this->status = Status::Connected;
399 return true;
400 }
401
406 bool TCPServerConnecter::CheckActivity()
407 {
408 if (this->killed) return true;
409
410 switch (this->server_address.type) {
411 case SERVER_ADDRESS_DIRECT:
412 return TCPConnecter::CheckActivity();
413
414 case SERVER_ADDRESS_INVITE_CODE:
415 /* Check if a result has come in. */
416 switch (this->status) {
417 case Status::Failure:
418 this->OnFailure();
419 return true;
420
421 case Status::Connected:
422 this->OnConnect(this->socket);
423 return true;
424
425 default:
426 break;
427 }
428
429 return false;
430
431 default:
432 NOT_REACHED();
433 }
434 }
435
441 void TCPServerConnecter::SetConnected(SOCKET sock)
442 {
443 assert(sock != INVALID_SOCKET);
444
445 this->socket = sock;
446 this->status = Status::Connected;
447 }
448
452 void TCPServerConnecter::SetFailure()
453 {
454 this->status = Status::Failure;
455 }
456
463 /* static */ void TCPConnecter::CheckCallbacks()
464 {
465 TCPConnecter::connecters.erase(
466 std::remove_if(TCPConnecter::connecters.begin(), TCPConnecter::connecters.end(),
467 [](auto &connecter) { return connecter->CheckActivity(); }),
468 TCPConnecter::connecters.end());
469 }
470
472 /* static */ void TCPConnecter::KillAll()
473 {
474 TCPConnecter::connecters.clear();
475 }
TCPServerConnecter::CheckActivity
bool CheckActivity() override
Check if there was activity for this connecter.
Definition: tcp_connect.cpp:406
TCPConnecter::CheckCallbacks
static void CheckCallbacks()
Check whether we need to call the callback, i.e.
Definition: tcp_connect.cpp:463
TCPConnecter::sockets
std::vector< SOCKET > sockets
Pending connect() attempts.
Definition: tcp.h:96
TCPConnecter::connection_string
std::string connection_string
Current address we are connecting to (before resolving).
Definition: tcp.h:99
NetworkAddress::GetAddress
const sockaddr_storage * GetAddress()
Get the address in its internal representation.
Definition: address.cpp:113
SetNonBlocking
bool SetNonBlocking([[maybe_unused]] SOCKET d)
Try to set the socket into non-blocking mode.
Definition: os_abstraction.cpp:133
NormalizeConnectionString
std::string NormalizeConnectionString(const std::string &connection_string, uint16_t default_port)
Normalize a connection string.
Definition: network.cpp:530
SetReusePort
bool SetReusePort(SOCKET d)
Try to set the socket to reuse ports.
Definition: os_abstraction.cpp:167
TCPConnecter
"Helper" class for creating TCP connections in a non-blocking manner
Definition: tcp.h:70
TCPConnecter::last_attempt
std::chrono::steady_clock::time_point last_attempt
Time we last tried to connect.
Definition: tcp.h:97
TCPConnecter::Kill
void Kill()
Kill this connecter.
Definition: tcp_connect.cpp:78
NetworkAddress::GetPort
uint16_t GetPort() const
Get the port.
Definition: address.cpp:38
TCPConnecter::family
int family
Family we are using to connect with.
Definition: tcp.h:101
NetworkError::HasError
bool HasError() const
Check whether an error was actually set.
Definition: os_abstraction.cpp:109
TCPConnecter::ai
addrinfo * ai
getaddrinfo() allocated linked-list of resolved addresses.
Definition: tcp.h:91
TCPServerConnecter::SetFailure
void SetFailure()
The connection couldn't be established.
Definition: tcp_connect.cpp:452
Debug
#define Debug(category, level, format_string,...)
Ouptut a line of debugging information.
Definition: debug.h:37
TCPConnecter::Status::Connecting
@ Connecting
We are currently connecting.
ServerAddress::type
ServerAddressType type
The type of this ServerAddress.
Definition: address.h:209
NetworkAddress::GetPeerName
static const std::string GetPeerName(SOCKET sock)
Get the peer name of a socket in string format.
Definition: address.cpp:435
TCPConnecter::connecters
static std::vector< std::shared_ptr< TCPConnecter > > connecters
List of connections that are currently being created.
Definition: tcp.h:103
ParseConnectionString
NetworkAddress ParseConnectionString(const std::string &connection_string, uint16_t default_port)
Convert a string containing either "hostname" or "hostname:ip" to a NetworkAddress.
Definition: network.cpp:545
TCPConnecter::Resolve
void Resolve()
Start resolving the hostname.
Definition: tcp_connect.cpp:220
ClientNetworkCoordinatorSocketHandler::ConnectToServer
void ConnectToServer(const std::string &invite_code, TCPServerConnecter *connecter)
Join a server based on an invite code.
Definition: network_coordinator.cpp:515
TCPConnecter::Connect
void Connect(addrinfo *address)
Start a connection to the indicated address.
Definition: tcp_connect.cpp:88
TCPConnecter::killed
std::atomic< bool > killed
Whether this connecter is marked as killed.
Definition: tcp.h:89
NetworkError::GetLast
static NetworkError GetLast()
Get the last network error.
Definition: os_abstraction.cpp:118
SERVER_ADDRESS_DIRECT
@ SERVER_ADDRESS_DIRECT
Server-address is based on an hostname:port.
Definition: address.h:187
StartNewThread
bool StartNewThread(std::thread *thr, const char *name, TFn &&_Fx, TArgs &&... _Ax)
Start a new thread.
Definition: thread.h:47
TCPConnecter::Status::Connected
@ Connected
The connection is established.
NetworkAddress::GetAddressAsString
std::string GetAddressAsString(bool with_family=true)
Get the address as a string, e.g.
Definition: address.cpp:94
TCPConnecter::KillAll
static void KillAll()
Kill all connection attempts.
Definition: tcp_connect.cpp:472
GetSocketError
NetworkError GetSocketError(SOCKET d)
Get the error from a socket, if any.
Definition: os_abstraction.cpp:184
SetNoDelay
bool SetNoDelay([[maybe_unused]] SOCKET d)
Try to set the socket to not delay sending.
Definition: os_abstraction.cpp:151
TCPConnecter::addresses
std::vector< addrinfo * > addresses
Addresses we can connect to.
Definition: tcp.h:92
TCPConnecter::Status::Failure
@ Failure
Resolving failed.
TCPServerConnecter::server_address
ServerAddress server_address
Address we are connecting to.
Definition: tcp.h:158
TCPConnecter::CheckActivity
virtual bool CheckActivity()
Check if there was activity for this connecter.
Definition: tcp_connect.cpp:271
NetworkAddress
Wrapper for (un)resolved network addresses; there's no reason to transform a numeric IP to a string a...
Definition: address.h:28
TCPServerConnecter::SetConnected
void SetConnected(SOCKET sock)
The connection was successfully established.
Definition: tcp_connect.cpp:441
TCPConnecter::current_address
size_t current_address
Current index in addresses we are trying.
Definition: tcp.h:94
tcp.h
_network_coordinator_client
ClientNetworkCoordinatorSocketHandler _network_coordinator_client
The connection to the Game Coordinator.
Definition: network_coordinator.cpp:30
TCPConnecter::Status::Resolving
@ Resolving
The hostname is being resolved (threaded).
TCPConnecter::sock_to_address
std::map< SOCKET, NetworkAddress > sock_to_address
Mapping of a socket to the real address it is connecting to. USed for DEBUG statements.
Definition: tcp.h:93
NetworkAddress::GetHostname
const std::string & GetHostname()
Get the hostname; in case it wasn't given the IPv4 dotted representation is given.
Definition: address.cpp:23
NetworkError::AsString
const std::string & AsString() const
Get the string representation of the error message.
Definition: os_abstraction.cpp:80
NetworkError
Abstraction of a network error where all implementation details of the error codes are encapsulated i...
Definition: os_abstraction.h:21
TCPConnecter::OnFailure
virtual void OnFailure()
Callback for when the connection attempt failed.
Definition: tcp.h:131
NetworkAddress::SocketTypeAsString
static const char * SocketTypeAsString(int socktype)
Convert the socket type into a string.
Definition: address.cpp:373
SERVER_ADDRESS_INVITE_CODE
@ SERVER_ADDRESS_INVITE_CODE
Server-address is based on an invite code.
Definition: address.h:188
TCPServerConnecter::TCPServerConnecter
TCPServerConnecter(const std::string &connection_string, uint16_t default_port)
Create a new connecter for the server.
Definition: tcp_connect.cpp:41
TCPConnecter::OnResolved
void OnResolved(addrinfo *ai)
Callback when resolving is done.
Definition: tcp_connect.cpp:148
TCPServerConnecter::socket
SOCKET socket
The socket when a connection is established.
Definition: tcp.h:153
TCPConnecter::OnConnect
virtual void OnConnect([[maybe_unused]] SOCKET s)
Callback when the connection succeeded.
Definition: tcp.h:126
NetworkAddress::AddressFamilyAsString
static const char * AddressFamilyAsString(int family)
Convert the address family into a string.
Definition: address.cpp:388
ServerAddress::connection_string
std::string connection_string
The connection string for this ServerAddress.
Definition: address.h:210
TCPConnecter::bind_address
NetworkAddress bind_address
Address we're binding to, if any.
Definition: tcp.h:100
ServerAddress
Address to a game server.
Definition: address.h:196
TCPConnecter::Status::Init
@ Init
TCPConnecter is created but resolving hasn't started.
TCPConnecter::status
std::atomic< Status > status
The current status of the connecter.
Definition: tcp.h:88
TCPConnecter::ResolveThunk
static void ResolveThunk(TCPConnecter *connecter)
Thunk to start Resolve() on the right instance.
Definition: tcp_connect.cpp:262
TCPConnecter::resolve_thread
std::thread resolve_thread
Thread used during resolving.
Definition: tcp.h:87
TCPConnecter::TryNextAddress
bool TryNextAddress()
Start the connect() for the next address in the list.
Definition: tcp_connect.cpp:134