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

OpenTTD Source 12.2

tcp_connect.cpp
Go to the documentation of this file.
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 <deque>
20
21 #include "../../safeguards.h"
22
24 static std::vector<TCPConnecter *> _tcp_connecters;
25
32 TCPConnecter::TCPConnecter(const std::string &connection_string, uint16 default_port, NetworkAddress bind_address, int family) :
33 bind_address(bind_address),
34 family(family)
35 {
36 this->connection_string = NormalizeConnectionString(connection_string, default_port);
37
38 _tcp_connecters.push_back(this);
39 }
40
46 TCPServerConnecter::TCPServerConnecter(const std::string &connection_string, uint16 default_port) :
47 server_address(ServerAddress::Parse(connection_string, default_port))
48 {
49 switch (this->server_address.type) {
50 case SERVER_ADDRESS_DIRECT:
51 this->connection_string = this->server_address.connection_string;
52 break;
53
54 case SERVER_ADDRESS_INVITE_CODE:
55 this->status = Status::CONNECTING;
56 _network_coordinator_client.ConnectToServer(this->server_address.connection_string, this);
57 break;
58
59 default:
60 NOT_REACHED();
61 }
62
63 _tcp_connecters.push_back(this);
64 }
65
66 TCPConnecter::~TCPConnecter()
67 {
68 if (this->resolve_thread.joinable()) {
69 this->resolve_thread.join();
70 }
71
72 for (const auto &socket : this->sockets) {
73 closesocket(socket);
74 }
75 this->sockets.clear();
76 this->sock_to_address.clear();
77
78 if (this->ai != nullptr) freeaddrinfo(this->ai);
79 }
80
85 void TCPConnecter::Kill()
86 {
87 /* Delay the removing of the socket till the next CheckActivity(). */
88 this->killed = true;
89 }
90
95 void TCPConnecter::Connect(addrinfo *address)
96 {
97 SOCKET sock = socket(address->ai_family, address->ai_socktype, address->ai_protocol);
98 if (sock == INVALID_SOCKET) {
99 Debug(net, 0, "Could not create {} {} socket: {}", NetworkAddress::SocketTypeAsString(address->ai_socktype), NetworkAddress::AddressFamilyAsString(address->ai_family), NetworkError::GetLast().AsString());
100 return;
101 }
102
103 if (!SetReusePort(sock)) {
104 Debug(net, 0, "Setting reuse-port mode failed: {}", NetworkError::GetLast().AsString());
105 }
106
107 if (this->bind_address.GetPort() > 0) {
108 if (bind(sock, (const sockaddr *)this->bind_address.GetAddress(), this->bind_address.GetAddressLength()) != 0) {
109 Debug(net, 1, "Could not bind socket on {}: {}", this->bind_address.GetAddressAsString(), NetworkError::GetLast().AsString());
110 closesocket(sock);
111 return;
112 }
113 }
114
115 if (!SetNoDelay(sock)) {
116 Debug(net, 1, "Setting TCP_NODELAY failed: {}", NetworkError::GetLast().AsString());
117 }
118 if (!SetNonBlocking(sock)) {
119 Debug(net, 0, "Setting non-blocking mode failed: {}", NetworkError::GetLast().AsString());
120 }
121
122 NetworkAddress network_address = NetworkAddress(address->ai_addr, (int)address->ai_addrlen);
123 Debug(net, 5, "Attempting to connect to {}", network_address.GetAddressAsString());
124
125 int err = connect(sock, address->ai_addr, (int)address->ai_addrlen);
126 if (err != 0 && !NetworkError::GetLast().IsConnectInProgress()) {
127 closesocket(sock);
128
129 Debug(net, 1, "Could not connect to {}: {}", network_address.GetAddressAsString(), NetworkError::GetLast().AsString());
130 return;
131 }
132
133 this->sock_to_address[sock] = network_address;
134 this->sockets.push_back(sock);
135 }
136
141 bool TCPConnecter::TryNextAddress()
142 {
143 if (this->current_address >= this->addresses.size()) return false;
144
145 this->last_attempt = std::chrono::steady_clock::now();
146 this->Connect(this->addresses[this->current_address++]);
147
148 return true;
149 }
150
155 void TCPConnecter::OnResolved(addrinfo *ai)
156 {
157 std::deque<addrinfo *> addresses_ipv4, addresses_ipv6;
158
159 /* Apply "Happy Eyeballs" if it is likely IPv6 is functional. */
160
161 /* Detect if IPv6 is likely to succeed or not. */
162 bool seen_ipv6 = false;
163 bool resort = true;
164 for (addrinfo *runp = ai; runp != nullptr; runp = runp->ai_next) {
165 if (runp->ai_family == AF_INET6) {
166 seen_ipv6 = true;
167 } else if (!seen_ipv6) {
168 /* We see an IPv4 before an IPv6; this most likely means there is
169 * no IPv6 available on the system, so keep the order of this
170 * list. */
171 resort = false;
172 break;
173 }
174 }
175
176 /* Convert the addrinfo into NetworkAddresses. */
177 for (addrinfo *runp = ai; runp != nullptr; runp = runp->ai_next) {
178 /* Skip entries if the family is set and it is not matching. */
179 if (this->family != AF_UNSPEC && this->family != runp->ai_family) continue;
180
181 if (resort) {
182 if (runp->ai_family == AF_INET6) {
183 addresses_ipv6.emplace_back(runp);
184 } else {
185 addresses_ipv4.emplace_back(runp);
186 }
187 } else {
188 this->addresses.emplace_back(runp);
189 }
190 }
191
192 /* If we want to resort, make the list like IPv6 / IPv4 / IPv6 / IPv4 / ..
193 * for how ever many (round-robin) DNS entries we have. */
194 if (resort) {
195 while (!addresses_ipv4.empty() || !addresses_ipv6.empty()) {
196 if (!addresses_ipv6.empty()) {
197 this->addresses.push_back(addresses_ipv6.front());
198 addresses_ipv6.pop_front();
199 }
200 if (!addresses_ipv4.empty()) {
201 this->addresses.push_back(addresses_ipv4.front());
202 addresses_ipv4.pop_front();
203 }
204 }
205 }
206
207 if (_debug_net_level >= 6) {
208 if (this->addresses.size() == 0) {
209 Debug(net, 6, "{} did not resolve", this->connection_string);
210 } else {
211 Debug(net, 6, "{} resolved in:", this->connection_string);
212 for (const auto &address : this->addresses) {
213 Debug(net, 6, "- {}", NetworkAddress(address->ai_addr, (int)address->ai_addrlen).GetAddressAsString());
214 }
215 }
216 }
217
218 this->current_address = 0;
219 }
220
227 void TCPConnecter::Resolve()
228 {
229 /* Port is already guaranteed part of the connection_string. */
230 NetworkAddress address = ParseConnectionString(this->connection_string, 0);
231
232 addrinfo hints;
233 memset(&hints, 0, sizeof(hints));
234 hints.ai_family = AF_UNSPEC;
235 hints.ai_flags = AI_ADDRCONFIG;
236 hints.ai_socktype = SOCK_STREAM;
237
238 char port_name[6];
239 seprintf(port_name, lastof(port_name), "%u", address.GetPort());
240
241 static bool getaddrinfo_timeout_error_shown = false;
242 auto start = std::chrono::steady_clock::now();
243
244 addrinfo *ai;
245 int error = getaddrinfo(address.GetHostname().c_str(), port_name, &hints, &ai);
246
247 auto end = std::chrono::steady_clock::now();
248 auto duration = std::chrono::duration_cast<std::chrono::seconds>(end - start);
249 if (!getaddrinfo_timeout_error_shown && duration >= std::chrono::seconds(5)) {
250 Debug(net, 0, "getaddrinfo() for address \"{}\" took {} seconds", this->connection_string, duration.count());
251 Debug(net, 0, " This is likely an issue in the DNS name resolver's configuration causing it to time out");
252 getaddrinfo_timeout_error_shown = true;
253 }
254
255 if (error != 0) {
256 Debug(net, 0, "Failed to resolve DNS for {}", this->connection_string);
257 this->status = Status::FAILURE;
258 return;
259 }
260
261 this->ai = ai;
262 this->OnResolved(ai);
263
264 this->status = Status::CONNECTING;
265 }
266
270 /* static */ void TCPConnecter::ResolveThunk(TCPConnecter *connecter)
271 {
272 connecter->Resolve();
273 }
274
279 bool TCPConnecter::CheckActivity()
280 {
281 if (this->killed) return true;
282
283 switch (this->status) {
284 case Status::INIT:
285 /* Start the thread delayed, so the vtable is loaded. This allows classes
286 * to overload functions used by Resolve() (in case threading is disabled). */
287 if (StartNewThread(&this->resolve_thread, "ottd:resolve", &TCPConnecter::ResolveThunk, this)) {
288 this->status = Status::RESOLVING;
289 return false;
290 }
291
292 /* No threads, do a blocking resolve. */
293 this->Resolve();
294
295 /* Continue as we are either failed or can start the first
296 * connection. The rest of this function handles exactly that. */
297 break;
298
299 case Status::RESOLVING:
300 /* Wait till Resolve() comes back with an answer (in case it runs threaded). */
301 return false;
302
303 case Status::FAILURE:
304 /* Ensure the OnFailure() is called from the game-thread instead of the
305 * resolve-thread, as otherwise we can get into some threading issues. */
306 this->OnFailure();
307 return true;
308
309 case Status::CONNECTING:
310 case Status::CONNECTED:
311 break;
312 }
313
314 /* If there are no attempts pending, connect to the next. */
315 if (this->sockets.empty()) {
316 if (!this->TryNextAddress()) {
317 /* There were no more addresses to try, so we failed. */
318 this->OnFailure();
319 return true;
320 }
321 return false;
322 }
323
324 fd_set write_fd;
325 FD_ZERO(&write_fd);
326 for (const auto &socket : this->sockets) {
327 FD_SET(socket, &write_fd);
328 }
329
330 timeval tv;
331 tv.tv_usec = 0;
332 tv.tv_sec = 0;
333 int n = select(FD_SETSIZE, nullptr, &write_fd, nullptr, &tv);
334 /* select() failed; hopefully next try it doesn't. */
335 if (n < 0) {
336 /* select() normally never fails; so hopefully it works next try! */
337 Debug(net, 1, "select() failed: {}", NetworkError::GetLast().AsString());
338 return false;
339 }
340
341 /* No socket updates. */
342 if (n == 0) {
343 /* Wait 250ms between attempting another address. */
344 if (std::chrono::steady_clock::now() < this->last_attempt + std::chrono::milliseconds(250)) return false;
345
346 /* Try the next address in the list. */
347 if (this->TryNextAddress()) return false;
348
349 /* Wait up to 3 seconds since the last connection we started. */
350 if (std::chrono::steady_clock::now() < this->last_attempt + std::chrono::milliseconds(3000)) return false;
351
352 /* More than 3 seconds no socket reported activity, and there are no
353 * more address to try. Timeout the attempt. */
354 Debug(net, 0, "Timeout while connecting to {}", this->connection_string);
355
356 for (const auto &socket : this->sockets) {
357 closesocket(socket);
358 }
359 this->sockets.clear();
360 this->sock_to_address.clear();
361
362 this->OnFailure();
363 return true;
364 }
365
366 /* If a socket is writeable, it is either in error-state or connected.
367 * Remove all sockets that are in error-state and mark the first that is
368 * not in error-state as the socket we will use for our connection. */
369 SOCKET connected_socket = INVALID_SOCKET;
370 for (auto it = this->sockets.begin(); it != this->sockets.end(); /* nothing */) {
371 NetworkError socket_error = GetSocketError(*it);
372 if (socket_error.HasError()) {
373 Debug(net, 1, "Could not connect to {}: {}", this->sock_to_address[*it].GetAddressAsString(), socket_error.AsString());
374 closesocket(*it);
375 this->sock_to_address.erase(*it);
376 it = this->sockets.erase(it);
377 continue;
378 }
379
380 /* No error but writeable means connected. */
381 if (connected_socket == INVALID_SOCKET && FD_ISSET(*it, &write_fd)) {
382 connected_socket = *it;
383 }
384
385 it++;
386 }
387
388 /* All the writable sockets were in error state. So nothing is connected yet. */
389 if (connected_socket == INVALID_SOCKET) return false;
390
391 /* Close all sockets except the one we picked for our connection. */
392 for (auto it = this->sockets.begin(); it != this->sockets.end(); /* nothing */) {
393 if (connected_socket != *it) {
394 closesocket(*it);
395 }
396 this->sock_to_address.erase(*it);
397 it = this->sockets.erase(it);
398 }
399
400 Debug(net, 3, "Connected to {}", this->connection_string);
401 if (_debug_net_level >= 5) {
402 Debug(net, 5, "- using {}", NetworkAddress::GetPeerName(connected_socket));
403 }
404
405 this->OnConnect(connected_socket);
406 this->status = Status::CONNECTED;
407 return true;
408 }
409
414 bool TCPServerConnecter::CheckActivity()
415 {
416 if (this->killed) return true;
417
418 switch (this->server_address.type) {
419 case SERVER_ADDRESS_DIRECT:
420 return TCPConnecter::CheckActivity();
421
422 case SERVER_ADDRESS_INVITE_CODE:
423 /* Check if a result has come in. */
424 switch (this->status) {
425 case Status::FAILURE:
426 this->OnFailure();
427 return true;
428
429 case Status::CONNECTED:
430 this->OnConnect(this->socket);
431 return true;
432
433 default:
434 break;
435 }
436
437 return false;
438
439 default:
440 NOT_REACHED();
441 }
442 }
443
449 void TCPServerConnecter::SetConnected(SOCKET sock)
450 {
451 assert(sock != INVALID_SOCKET);
452
453 this->socket = sock;
454 this->status = Status::CONNECTED;
455 }
456
460 void TCPServerConnecter::SetFailure()
461 {
462 this->status = Status::FAILURE;
463 }
464
471 /* static */ void TCPConnecter::CheckCallbacks()
472 {
473 for (auto iter = _tcp_connecters.begin(); iter < _tcp_connecters.end(); /* nothing */) {
474 TCPConnecter *cur = *iter;
475
476 if (cur->CheckActivity()) {
477 iter = _tcp_connecters.erase(iter);
478 delete cur;
479 } else {
480 iter++;
481 }
482 }
483 }
484
486 /* static */ void TCPConnecter::KillAll()
487 {
488 for (auto iter = _tcp_connecters.begin(); iter < _tcp_connecters.end(); /* nothing */) {
489 TCPConnecter *cur = *iter;
490 iter = _tcp_connecters.erase(iter);
491 delete cur;
492 }
493 }
TCPServerConnecter::CheckActivity
bool CheckActivity() override
Check if there was activity for this connecter.
Definition: tcp_connect.cpp:414
TCPConnecter::CheckCallbacks
static void CheckCallbacks()
Check whether we need to call the callback, i.e.
Definition: tcp_connect.cpp:471
TCPConnecter::OnConnect
virtual void OnConnect(SOCKET s)
Callback when the connection succeeded.
Definition: tcp.h:125
TCPConnecter::sockets
std::vector< SOCKET > sockets
Pending connect() attempts.
Definition: tcp.h:97
TCPConnecter::connection_string
std::string connection_string
Current address we are connecting to (before resolving).
Definition: tcp.h:100
TCPConnecter::Status::CONNECTED
@ CONNECTED
The connection is established.
NetworkAddress::GetAddress
const sockaddr_storage * GetAddress()
Get the address in its internal representation.
Definition: address.cpp:114
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:71
TCPConnecter::last_attempt
std::chrono::steady_clock::time_point last_attempt
Time we last tried to connect.
Definition: tcp.h:98
ParseConnectionString
NetworkAddress ParseConnectionString(const std::string &connection_string, uint16 default_port)
Convert a string containing either "hostname" or "hostname:ip" to a NetworkAddress.
Definition: network.cpp:541
TCPConnecter::Kill
void Kill()
Kill this connecter.
Definition: tcp_connect.cpp:85
TCPConnecter::family
int family
Family we are using to connect with.
Definition: tcp.h:102
NetworkError::HasError
bool HasError() const
Check whether an error was actually set.
Definition: os_abstraction.cpp:107
TCPConnecter::ai
addrinfo * ai
getaddrinfo() allocated linked-list of resolved addresses.
Definition: tcp.h:92
TCPServerConnecter::SetFailure
void SetFailure()
The connection couldn't be established.
Definition: tcp_connect.cpp:460
ServerAddress::type
ServerAddressType type
The type of this ServerAddress.
Definition: address.h:211
NetworkAddress::GetPeerName
static const std::string GetPeerName(SOCKET sock)
Get the peer name of a socket in string format.
Definition: address.cpp:439
TCPConnecter::Resolve
void Resolve()
Start resolving the hostname.
Definition: tcp_connect.cpp:227
ClientNetworkCoordinatorSocketHandler::ConnectToServer
void ConnectToServer(const std::string &invite_code, TCPServerConnecter *connecter)
Join a server based on an invite code.
Definition: network_coordinator.cpp:515
_tcp_connecters
static std::vector< TCPConnecter * > _tcp_connecters
List of connections that are currently being created.
Definition: tcp_connect.cpp:24
NormalizeConnectionString
std::string NormalizeConnectionString(const std::string &connection_string, uint16 default_port)
Normalize a connection string.
Definition: network.cpp:526
TCPConnecter::Connect
void Connect(addrinfo *address)
Start a connection to the indicated address.
Definition: tcp_connect.cpp:95
TCPConnecter::killed
std::atomic< bool > killed
Whether this connecter is marked as killed.
Definition: tcp.h:90
NetworkError::GetLast
static NetworkError GetLast()
Get the last network error.
Definition: os_abstraction.cpp:116
SERVER_ADDRESS_DIRECT
@ SERVER_ADDRESS_DIRECT
Server-address is based on an hostname:port.
Definition: address.h:189
TCPConnecter::Status::RESOLVING
@ RESOLVING
The hostname is being resolved (threaded).
StartNewThread
bool StartNewThread(std::thread *thr, const char *name, TFn &&_Fx, TArgs &&... _Ax)
Start a new thread.
Definition: thread.h:46
NetworkAddress::GetPort
uint16 GetPort() const
Get the port.
Definition: address.cpp:38
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:486
GetSocketError
NetworkError GetSocketError(SOCKET d)
Get the error from a socket, if any.
Definition: os_abstraction.cpp:184
TCPConnecter::addresses
std::vector< addrinfo * > addresses
Addresses we can connect to.
Definition: tcp.h:93
TCPServerConnecter::server_address
ServerAddress server_address
Address we are connecting to.
Definition: tcp.h:145
TCPConnecter::CheckActivity
virtual bool CheckActivity()
Check if there was activity for this connecter.
Definition: tcp_connect.cpp:279
NetworkAddress
Wrapper for (un)resolved network addresses; there's no reason to transform a numeric IP to a string a...
Definition: address.h:30
TCPServerConnecter::SetConnected
void SetConnected(SOCKET sock)
The connection was successfully established.
Definition: tcp_connect.cpp:449
TCPConnecter::current_address
size_t current_address
Current index in addresses we are trying.
Definition: tcp.h:95
tcp.h
_network_coordinator_client
ClientNetworkCoordinatorSocketHandler _network_coordinator_client
The connection to the Game Coordinator.
Definition: network_coordinator.cpp:30
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:94
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:79
seprintf
int CDECL seprintf(char *str, const char *last, const char *format,...)
Safer implementation of snprintf; same as snprintf except:
Definition: string.cpp:535
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:130
NetworkAddress::SocketTypeAsString
static const char * SocketTypeAsString(int socktype)
Convert the socket type into a string.
Definition: address.cpp:377
SERVER_ADDRESS_INVITE_CODE
@ SERVER_ADDRESS_INVITE_CODE
Server-address is based on an invite code.
Definition: address.h:190
error
void CDECL error(const char *s,...)
Error handling for fatal non-user errors.
Definition: openttd.cpp:132
Debug
#define Debug(name, level, format_string,...)
Ouptut a line of debugging information.
Definition: debug.h:37
SetNonBlocking
bool SetNonBlocking(SOCKET d)
Try to set the socket into non-blocking mode.
Definition: os_abstraction.cpp:133
TCPConnecter::OnResolved
void OnResolved(addrinfo *ai)
Callback when resolving is done.
Definition: tcp_connect.cpp:155
TCPServerConnecter::socket
SOCKET socket
The socket when a connection is established.
Definition: tcp.h:140
TCPConnecter::Status::FAILURE
@ FAILURE
Resolving failed.
NetworkAddress::AddressFamilyAsString
static const char * AddressFamilyAsString(int family)
Convert the address family into a string.
Definition: address.cpp:392
ServerAddress::connection_string
std::string connection_string
The connection string for this ServerAddress.
Definition: address.h:212
lastof
#define lastof(x)
Get the last element of an fixed size array.
Definition: stdafx.h:394
TCPConnecter::bind_address
NetworkAddress bind_address
Address we're binding to, if any.
Definition: tcp.h:101
SetNoDelay
bool SetNoDelay(SOCKET d)
Try to set the socket to not delay sending.
Definition: os_abstraction.cpp:151
TCPConnecter::Status::CONNECTING
@ CONNECTING
We are currently connecting.
ServerAddress
Address to a game server.
Definition: address.h:198
TCPServerConnecter::TCPServerConnecter
TCPServerConnecter(const std::string &connection_string, uint16 default_port)
Create a new connecter for the server.
Definition: tcp_connect.cpp:46
TCPConnecter::status
std::atomic< Status > status
The current status of the connecter.
Definition: tcp.h:89
TCPConnecter::ResolveThunk
static void ResolveThunk(TCPConnecter *connecter)
Thunk to start Resolve() on the right instance.
Definition: tcp_connect.cpp:270
TCPConnecter::Status::INIT
@ INIT
TCPConnecter is created but resolving hasn't started.
TCPConnecter::resolve_thread
std::thread resolve_thread
Thread used during resolving.
Definition: tcp.h:88
TCPConnecter::TryNextAddress
bool TryNextAddress()
Start the connect() for the next address in the list.
Definition: tcp_connect.cpp:141