1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
|
/*
* This file is part of OpenTTD.
* 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.
* 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.
* 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/>.
*/
/**
* @file os_abstraction.cpp OS specific implementations of functions of the OS abstraction layer for network stuff.
*
* The general idea is to have simple abstracting functions for things that
* require different implementations for different environments.
* In here the functions, and their documentation, are defined only once
* and the implementation contains the #ifdefs to change the implementation.
* Since Windows is usually different that is usually the first case, after
* that the behaviour is usually Unix/BSD-like with occasional variation.
*/
#include "stdafx.h"
#include "os_abstraction.h"
#include "../../string_func.h"
#include <mutex>
#include "../../safeguards.h"
/**
* Construct the network error with the given error code.
* @param error The error code.
*/
NetworkError::NetworkError(int error) : error(error)
{
}
/**
* Check whether this error describes that the operation would block.
* @return True iff the operation would block.
*/
bool NetworkError::WouldBlock() const
{
#if defined(_WIN32)
return this->error == WSAEWOULDBLOCK;
#else
/* Usually EWOULDBLOCK and EAGAIN are the same, but sometimes they are not
* and the POSIX.1 specification states that either should be checked. */
return this->error == EWOULDBLOCK || this->error == EAGAIN;
#endif
}
/**
* Check whether this error describes a connection reset.
* @return True iff the connection is reset.
*/
bool NetworkError::IsConnectionReset() const
{
#if defined(_WIN32)
return this->error == WSAECONNRESET;
#else
return this->error == ECONNRESET;
#endif
}
/**
* Check whether this error describes a connect is in progress.
* @return True iff the connect is already in progress.
*/
bool NetworkError::IsConnectInProgress() const
{
#if defined(_WIN32)
return this->error == WSAEWOULDBLOCK;
#else
return this->error == EINPROGRESS;
#endif
}
/**
* Get the string representation of the error message.
* @return The string representation that will get overwritten by next calls.
*/
const std::string &NetworkError::AsString() const
{
if (this->message.empty()) {
#if defined(_WIN32)
char buffer[512];
if (FormatMessageA(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, NULL, this->error,
MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), buffer, sizeof(buffer), NULL) == 0) {
seprintf(buffer, lastof(buffer), "Unknown error %d", this->error);
}
this->message.assign(buffer);
#else
/* Make strerror thread safe by locking access to it. There is a thread safe strerror_r, however
* the non-POSIX variant is available due to defining _GNU_SOURCE meaning it is not portable.
* The problem with the non-POSIX variant is that it does not necessarily fill the buffer with
* the error message but can also return a pointer to a static bit of memory, whereas the POSIX
* variant always fills the buffer. This makes the behaviour too erratic to work with. */
static std::mutex mutex;
std::lock_guard<std::mutex> guard(mutex);
this->message.assign(strerror(this->error));
#endif
}
return this->message;
}
/**
* Check whether an error was actually set.
* @return True iff an error was set.
*/
bool NetworkError::HasError() const
{
return this->error != 0;
}
/**
* Get the last network error.
* @return The network error.
*/
/* static */ NetworkError NetworkError::GetLast()
{
#if defined(_WIN32)
return NetworkError(WSAGetLastError());
#elif defined(__OS2__)
return NetworkError(sock_errno());
#else
return NetworkError(errno);
#endif
}
/**
* Try to set the socket into non-blocking mode.
* @param d The socket to set the non-blocking more for.
* @return True if setting the non-blocking mode succeeded, otherwise false.
*/
bool SetNonBlocking(SOCKET d)
{
#if defined(_WIN32)
u_long nonblocking = 1;
return ioctlsocket(d, FIONBIO, &nonblocking) == 0;
#elif defined __EMSCRIPTEN__
return true;
#else
int nonblocking = 1;
return ioctl(d, FIONBIO, &nonblocking) == 0;
#endif
}
/**
* Try to set the socket to not delay sending.
* @param d The socket to disable the delaying for.
* @return True if disabling the delaying succeeded, otherwise false.
*/
bool SetNoDelay(SOCKET d)
{
#ifdef __EMSCRIPTEN__
return true;
#else
int flags = 1;
/* The (const char*) cast is needed for windows */
return setsockopt(d, IPPROTO_TCP, TCP_NODELAY, (const char *)&flags, sizeof(flags)) == 0;
#endif
}
/**
* Try to set the socket to reuse ports.
* @param d The socket to reuse ports on.
* @return True if disabling the delaying succeeded, otherwise false.
*/
bool SetReusePort(SOCKET d)
{
#ifdef _WIN32
/* Windows has no SO_REUSEPORT, but for our usecases SO_REUSEADDR does the same job. */
int reuse_port = 1;
return setsockopt(d, SOL_SOCKET, SO_REUSEADDR, (const char *)&reuse_port, sizeof(reuse_port)) == 0;
#else
int reuse_port = 1;
return setsockopt(d, SOL_SOCKET, SO_REUSEPORT, &reuse_port, sizeof(reuse_port)) == 0;
#endif
}
/**
* Get the error from a socket, if any.
* @param d The socket to get the error from.
* @return The errno on the socket.
*/
NetworkError GetSocketError(SOCKET d)
{
int err;
socklen_t len = sizeof(err);
getsockopt(d, SOL_SOCKET, SO_ERROR, (char *)&err, &len);
return NetworkError(err);
}
|
