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

OpenTTD Source 14.0-beta1

tcp.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 "../../debug.h"
14
15 #include "tcp.h"
16
17 #include "../../safeguards.h"
18
23 NetworkTCPSocketHandler::NetworkTCPSocketHandler(SOCKET s) :
24 NetworkSocketHandler(),
25 packet_queue(nullptr), packet_recv(nullptr),
26 sock(s), writable(false)
27 {
28 }
29
30 NetworkTCPSocketHandler::~NetworkTCPSocketHandler()
31 {
32 this->EmptyPacketQueue();
33 this->CloseSocket();
34 }
35
39 void NetworkTCPSocketHandler::EmptyPacketQueue()
40 {
41 while (this->packet_queue != nullptr) {
42 delete Packet::PopFromQueue(&this->packet_queue);
43 }
44 delete this->packet_recv;
45 this->packet_recv = nullptr;
46 }
47
53 void NetworkTCPSocketHandler::CloseSocket()
54 {
55 if (this->sock != INVALID_SOCKET) closesocket(this->sock);
56 this->sock = INVALID_SOCKET;
57 }
58
65 NetworkRecvStatus NetworkTCPSocketHandler::CloseConnection([[maybe_unused]] bool error)
66 {
67 this->MarkClosed();
68 this->writable = false;
69
70 this->EmptyPacketQueue();
71
72 return NETWORK_RECV_STATUS_OKAY;
73 }
74
81 void NetworkTCPSocketHandler::SendPacket(Packet *packet)
82 {
83 assert(packet != nullptr);
84
85 packet->PrepareToSend();
86 Packet::AddToQueue(&this->packet_queue, packet);
87 }
88
99 SendPacketsState NetworkTCPSocketHandler::SendPackets(bool closing_down)
100 {
101 ssize_t res;
102 Packet *p;
103
104 /* We can not write to this socket!! */
105 if (!this->writable) return SPS_NONE_SENT;
106 if (!this->IsConnected()) return SPS_CLOSED;
107
108 while ((p = this->packet_queue) != nullptr) {
109 res = p->TransferOut<int>(send, this->sock, 0);
110 if (res == -1) {
111 NetworkError err = NetworkError::GetLast();
112 if (!err.WouldBlock()) {
113 /* Something went wrong.. close client! */
114 if (!closing_down) {
115 Debug(net, 0, "Send failed: {}", err.AsString());
116 this->CloseConnection();
117 }
118 return SPS_CLOSED;
119 }
120 return SPS_PARTLY_SENT;
121 }
122 if (res == 0) {
123 /* Client/server has left us :( */
124 if (!closing_down) this->CloseConnection();
125 return SPS_CLOSED;
126 }
127
128 /* Is this packet sent? */
129 if (p->RemainingBytesToTransfer() == 0) {
130 /* Go to the next packet */
131 delete Packet::PopFromQueue(&this->packet_queue);
132 } else {
133 return SPS_PARTLY_SENT;
134 }
135 }
136
137 return SPS_ALL_SENT;
138 }
139
144 Packet *NetworkTCPSocketHandler::ReceivePacket()
145 {
146 ssize_t res;
147
148 if (!this->IsConnected()) return nullptr;
149
150 if (this->packet_recv == nullptr) {
151 this->packet_recv = new Packet(this, TCP_MTU);
152 }
153
154 Packet *p = this->packet_recv;
155
156 /* Read packet size */
157 if (!p->HasPacketSizeData()) {
158 while (p->RemainingBytesToTransfer() != 0) {
159 res = p->TransferIn<int>(recv, this->sock, 0);
160 if (res == -1) {
161 NetworkError err = NetworkError::GetLast();
162 if (!err.WouldBlock()) {
163 /* Something went wrong... */
164 if (!err.IsConnectionReset()) Debug(net, 0, "Recv failed: {}", err.AsString());
165 this->CloseConnection();
166 return nullptr;
167 }
168 /* Connection would block, so stop for now */
169 return nullptr;
170 }
171 if (res == 0) {
172 /* Client/server has left */
173 this->CloseConnection();
174 return nullptr;
175 }
176 }
177
178 /* Parse the size in the received packet and if not valid, close the connection. */
179 if (!p->ParsePacketSize()) {
180 this->CloseConnection();
181 return nullptr;
182 }
183 }
184
185 /* Read rest of packet */
186 while (p->RemainingBytesToTransfer() != 0) {
187 res = p->TransferIn<int>(recv, this->sock, 0);
188 if (res == -1) {
189 NetworkError err = NetworkError::GetLast();
190 if (!err.WouldBlock()) {
191 /* Something went wrong... */
192 if (!err.IsConnectionReset()) Debug(net, 0, "Recv failed: {}", err.AsString());
193 this->CloseConnection();
194 return nullptr;
195 }
196 /* Connection would block */
197 return nullptr;
198 }
199 if (res == 0) {
200 /* Client/server has left */
201 this->CloseConnection();
202 return nullptr;
203 }
204 }
205
206 /* Prepare for receiving a new packet */
207 this->packet_recv = nullptr;
208
209 p->PrepareToRead();
210 return p;
211 }
212
218 bool NetworkTCPSocketHandler::CanSendReceive()
219 {
220 assert(this->sock != INVALID_SOCKET);
221
222 fd_set read_fd, write_fd;
223 struct timeval tv;
224
225 FD_ZERO(&read_fd);
226 FD_ZERO(&write_fd);
227
228 FD_SET(this->sock, &read_fd);
229 FD_SET(this->sock, &write_fd);
230
231 tv.tv_sec = tv.tv_usec = 0; // don't block at all.
232 if (select(FD_SETSIZE, &read_fd, &write_fd, nullptr, &tv) < 0) return false;
233
234 this->writable = !!FD_ISSET(this->sock, &write_fd);
235 return FD_ISSET(this->sock, &read_fd) != 0;
236 }
Packet::PrepareToSend
void PrepareToSend()
Writes the packet size from the raw packet from packet->size.
Definition: packet.cpp:83
NetworkSocketHandler
SocketHandler for all network sockets in OpenTTD.
Definition: core.h:42
SPS_CLOSED
@ SPS_CLOSED
The connection got closed.
Definition: tcp.h:24
NetworkTCPSocketHandler::IsConnected
bool IsConnected() const
Whether this socket is currently bound to a socket.
Definition: tcp.h:45
Packet::HasPacketSizeData
bool HasPacketSizeData() const
Check whether the packet, given the position of the "write" pointer, has read enough of the packet to...
Definition: packet.cpp:248
NetworkTCPSocketHandler::sock
SOCKET sock
The socket currently connected to.
Definition: tcp.h:38
Packet::TransferOut
ssize_t TransferOut(F transfer_function, D destination, Args &&... args)
Transfer data from the packet to the given function.
Definition: packet.h:141
Packet::ParsePacketSize
bool ParsePacketSize()
Reads the packet size from the raw packet and stores it in the packet->size.
Definition: packet.cpp:269
SPS_ALL_SENT
@ SPS_ALL_SENT
All packets in the queue are sent.
Definition: tcp.h:27
Debug
#define Debug(category, level, format_string,...)
Ouptut a line of debugging information.
Definition: debug.h:37
Packet::AddToQueue
static void AddToQueue(Packet **queue, Packet *packet)
Add the given Packet to the end of the queue of packets.
Definition: packet.cpp:59
NetworkTCPSocketHandler::ReceivePacket
virtual Packet * ReceivePacket()
Receives a packet for the given client.
Definition: tcp.cpp:144
Packet::PopFromQueue
static Packet * PopFromQueue(Packet **queue)
Pop the packet from the begin of the queue and set the begin of the queue to the second element in th...
Definition: packet.cpp:71
NetworkTCPSocketHandler::packet_recv
Packet * packet_recv
Partially received packet.
Definition: tcp.h:34
SendPacketsState
SendPacketsState
The states of sending the packets.
Definition: tcp.h:23
Packet::PrepareToRead
void PrepareToRead()
Prepares the packet so it can be read.
Definition: packet.cpp:288
NetworkError::WouldBlock
bool WouldBlock() const
Check whether this error describes that the operation would block.
Definition: os_abstraction.cpp:39
NetworkError::GetLast
static NetworkError GetLast()
Get the last network error.
Definition: os_abstraction.cpp:118
NetworkSocketHandler::MarkClosed
void MarkClosed()
Mark the connection as closed.
Definition: core.h:60
NetworkTCPSocketHandler::SendPacket
virtual void SendPacket(Packet *packet)
This function puts the packet in the send-queue and it is send as soon as possible.
Definition: tcp.cpp:81
NetworkTCPSocketHandler::CloseConnection
virtual NetworkRecvStatus CloseConnection(bool error=true)
This will put this socket handler in a close state.
Definition: tcp.cpp:65
Packet::TransferIn
ssize_t TransferIn(F transfer_function, S source, Args &&... args)
Transfer data from the given function into the packet.
Definition: packet.h:176
Packet
Internal entity of a packet.
Definition: packet.h:42
NetworkTCPSocketHandler::NetworkTCPSocketHandler
NetworkTCPSocketHandler(SOCKET s=INVALID_SOCKET)
Construct a socket handler for a TCP connection.
Definition: tcp.cpp:23
NetworkTCPSocketHandler::EmptyPacketQueue
void EmptyPacketQueue()
Free all pending and partially received packets.
Definition: tcp.cpp:39
NetworkTCPSocketHandler::writable
bool writable
Can we write to this socket?
Definition: tcp.h:39
SPS_NONE_SENT
@ SPS_NONE_SENT
The buffer is still full, so no (parts of) packets could be sent.
Definition: tcp.h:25
NetworkTCPSocketHandler::SendPackets
SendPacketsState SendPackets(bool closing_down=false)
Sends all the buffered packets out for this client.
Definition: tcp.cpp:99
NetworkTCPSocketHandler::CanSendReceive
bool CanSendReceive()
Check whether this socket can send or receive something.
Definition: tcp.cpp:218
NetworkRecvStatus
NetworkRecvStatus
Status of a network client; reasons why a client has quit.
Definition: core.h:22
tcp.h
NetworkError::IsConnectionReset
bool IsConnectionReset() const
Check whether this error describes a connection reset.
Definition: os_abstraction.cpp:54
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
SPS_PARTLY_SENT
@ SPS_PARTLY_SENT
The packets are partly sent; there are more packets to be sent in the queue.
Definition: tcp.h:26
NETWORK_RECV_STATUS_OKAY
@ NETWORK_RECV_STATUS_OKAY
Everything is okay.
Definition: core.h:23
TCP_MTU
static const uint16_t TCP_MTU
Number of bytes we can pack in a single TCP packet.
Definition: config.h:45
Packet::RemainingBytesToTransfer
size_t RemainingBytesToTransfer() const
Get the amount of bytes that are still available for the Transfer functions.
Definition: packet.cpp:430
NetworkTCPSocketHandler::CloseSocket
void CloseSocket()
Close the actual socket of the connection.
Definition: tcp.cpp:53
NetworkTCPSocketHandler::packet_queue
Packet * packet_queue
Packets that are awaiting delivery.
Definition: tcp.h:33