aboutsummaryrefslogtreecommitdiff
path: root/src/util/sock.cpp
blob: 84ac2759faaab981680abbdc50536d74eb9349ef (plain)
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
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
// Copyright (c) 2020-2021 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include <compat/compat.h>
#include <logging.h>
#include <threadinterrupt.h>
#include <tinyformat.h>
#include <util/sock.h>
#include <util/syserror.h>
#include <util/system.h>
#include <util/time.h>

#include <memory>
#include <stdexcept>
#include <string>

#ifdef WIN32
#include <codecvt>
#include <locale>
#endif

#ifdef USE_POLL
#include <poll.h>
#endif

static inline bool IOErrorIsPermanent(int err)
{
    return err != WSAEAGAIN && err != WSAEINTR && err != WSAEWOULDBLOCK && err != WSAEINPROGRESS;
}

Sock::Sock() : m_socket(INVALID_SOCKET) {}

Sock::Sock(SOCKET s) : m_socket(s) {}

Sock::Sock(Sock&& other)
{
    m_socket = other.m_socket;
    other.m_socket = INVALID_SOCKET;
}

Sock::~Sock() { Close(); }

Sock& Sock::operator=(Sock&& other)
{
    Close();
    m_socket = other.m_socket;
    other.m_socket = INVALID_SOCKET;
    return *this;
}

SOCKET Sock::Get() const { return m_socket; }

ssize_t Sock::Send(const void* data, size_t len, int flags) const
{
    return send(m_socket, static_cast<const char*>(data), len, flags);
}

ssize_t Sock::Recv(void* buf, size_t len, int flags) const
{
    return recv(m_socket, static_cast<char*>(buf), len, flags);
}

int Sock::Connect(const sockaddr* addr, socklen_t addr_len) const
{
    return connect(m_socket, addr, addr_len);
}

int Sock::Bind(const sockaddr* addr, socklen_t addr_len) const
{
    return bind(m_socket, addr, addr_len);
}

int Sock::Listen(int backlog) const
{
    return listen(m_socket, backlog);
}

std::unique_ptr<Sock> Sock::Accept(sockaddr* addr, socklen_t* addr_len) const
{
#ifdef WIN32
    static constexpr auto ERR = INVALID_SOCKET;
#else
    static constexpr auto ERR = SOCKET_ERROR;
#endif

    std::unique_ptr<Sock> sock;

    const auto socket = accept(m_socket, addr, addr_len);
    if (socket != ERR) {
        try {
            sock = std::make_unique<Sock>(socket);
        } catch (const std::exception&) {
#ifdef WIN32
            closesocket(socket);
#else
            close(socket);
#endif
        }
    }

    return sock;
}

int Sock::GetSockOpt(int level, int opt_name, void* opt_val, socklen_t* opt_len) const
{
    return getsockopt(m_socket, level, opt_name, static_cast<char*>(opt_val), opt_len);
}

int Sock::SetSockOpt(int level, int opt_name, const void* opt_val, socklen_t opt_len) const
{
    return setsockopt(m_socket, level, opt_name, static_cast<const char*>(opt_val), opt_len);
}

int Sock::GetSockName(sockaddr* name, socklen_t* name_len) const
{
    return getsockname(m_socket, name, name_len);
}

bool Sock::SetNonBlocking() const
{
#ifdef WIN32
    u_long on{1};
    if (ioctlsocket(m_socket, FIONBIO, &on) == SOCKET_ERROR) {
        return false;
    }
#else
    const int flags{fcntl(m_socket, F_GETFL, 0)};
    if (flags == SOCKET_ERROR) {
        return false;
    }
    if (fcntl(m_socket, F_SETFL, flags | O_NONBLOCK) == SOCKET_ERROR) {
        return false;
    }
#endif
    return true;
}

bool Sock::IsSelectable() const
{
#if defined(USE_POLL) || defined(WIN32)
    return true;
#else
    return m_socket < FD_SETSIZE;
#endif
}

bool Sock::Wait(std::chrono::milliseconds timeout, Event requested, Event* occurred) const
{
    // We need a `shared_ptr` owning `this` for `WaitMany()`, but don't want
    // `this` to be destroyed when the `shared_ptr` goes out of scope at the
    // end of this function. Create it with a custom noop deleter.
    std::shared_ptr<const Sock> shared{this, [](const Sock*) {}};

    EventsPerSock events_per_sock{std::make_pair(shared, Events{requested})};

    if (!WaitMany(timeout, events_per_sock)) {
        return false;
    }

    if (occurred != nullptr) {
        *occurred = events_per_sock.begin()->second.occurred;
    }

    return true;
}

bool Sock::WaitMany(std::chrono::milliseconds timeout, EventsPerSock& events_per_sock) const
{
#ifdef USE_POLL
    std::vector<pollfd> pfds;
    for (const auto& [sock, events] : events_per_sock) {
        pfds.emplace_back();
        auto& pfd = pfds.back();
        pfd.fd = sock->m_socket;
        if (events.requested & RECV) {
            pfd.events |= POLLIN;
        }
        if (events.requested & SEND) {
            pfd.events |= POLLOUT;
        }
    }

    if (poll(pfds.data(), pfds.size(), count_milliseconds(timeout)) == SOCKET_ERROR) {
        return false;
    }

    assert(pfds.size() == events_per_sock.size());
    size_t i{0};
    for (auto& [sock, events] : events_per_sock) {
        assert(sock->m_socket == static_cast<SOCKET>(pfds[i].fd));
        events.occurred = 0;
        if (pfds[i].revents & POLLIN) {
            events.occurred |= RECV;
        }
        if (pfds[i].revents & POLLOUT) {
            events.occurred |= SEND;
        }
        if (pfds[i].revents & (POLLERR | POLLHUP)) {
            events.occurred |= ERR;
        }
        ++i;
    }

    return true;
#else
    fd_set recv;
    fd_set send;
    fd_set err;
    FD_ZERO(&recv);
    FD_ZERO(&send);
    FD_ZERO(&err);
    SOCKET socket_max{0};

    for (const auto& [sock, events] : events_per_sock) {
        if (!sock->IsSelectable()) {
            return false;
        }
        const auto& s = sock->m_socket;
        if (events.requested & RECV) {
            FD_SET(s, &recv);
        }
        if (events.requested & SEND) {
            FD_SET(s, &send);
        }
        FD_SET(s, &err);
        socket_max = std::max(socket_max, s);
    }

    timeval tv = MillisToTimeval(timeout);

    if (select(socket_max + 1, &recv, &send, &err, &tv) == SOCKET_ERROR) {
        return false;
    }

    for (auto& [sock, events] : events_per_sock) {
        const auto& s = sock->m_socket;
        events.occurred = 0;
        if (FD_ISSET(s, &recv)) {
            events.occurred |= RECV;
        }
        if (FD_ISSET(s, &send)) {
            events.occurred |= SEND;
        }
        if (FD_ISSET(s, &err)) {
            events.occurred |= ERR;
        }
    }

    return true;
#endif /* USE_POLL */
}

void Sock::SendComplete(const std::string& data,
                        std::chrono::milliseconds timeout,
                        CThreadInterrupt& interrupt) const
{
    const auto deadline = GetTime<std::chrono::milliseconds>() + timeout;
    size_t sent{0};

    for (;;) {
        const ssize_t ret{Send(data.data() + sent, data.size() - sent, MSG_NOSIGNAL)};

        if (ret > 0) {
            sent += static_cast<size_t>(ret);
            if (sent == data.size()) {
                break;
            }
        } else {
            const int err{WSAGetLastError()};
            if (IOErrorIsPermanent(err)) {
                throw std::runtime_error(strprintf("send(): %s", NetworkErrorString(err)));
            }
        }

        const auto now = GetTime<std::chrono::milliseconds>();

        if (now >= deadline) {
            throw std::runtime_error(strprintf(
                "Send timeout (sent only %u of %u bytes before that)", sent, data.size()));
        }

        if (interrupt) {
            throw std::runtime_error(strprintf(
                "Send interrupted (sent only %u of %u bytes before that)", sent, data.size()));
        }

        // Wait for a short while (or the socket to become ready for sending) before retrying
        // if nothing was sent.
        const auto wait_time = std::min(deadline - now, std::chrono::milliseconds{MAX_WAIT_FOR_IO});
        (void)Wait(wait_time, SEND);
    }
}

std::string Sock::RecvUntilTerminator(uint8_t terminator,
                                      std::chrono::milliseconds timeout,
                                      CThreadInterrupt& interrupt,
                                      size_t max_data) const
{
    const auto deadline = GetTime<std::chrono::milliseconds>() + timeout;
    std::string data;
    bool terminator_found{false};

    // We must not consume any bytes past the terminator from the socket.
    // One option is to read one byte at a time and check if we have read a terminator.
    // However that is very slow. Instead, we peek at what is in the socket and only read
    // as many bytes as possible without crossing the terminator.
    // Reading 64 MiB of random data with 262526 terminator chars takes 37 seconds to read
    // one byte at a time VS 0.71 seconds with the "peek" solution below. Reading one byte
    // at a time is about 50 times slower.

    for (;;) {
        if (data.size() >= max_data) {
            throw std::runtime_error(
                strprintf("Received too many bytes without a terminator (%u)", data.size()));
        }

        char buf[512];

        const ssize_t peek_ret{Recv(buf, std::min(sizeof(buf), max_data - data.size()), MSG_PEEK)};

        switch (peek_ret) {
        case -1: {
            const int err{WSAGetLastError()};
            if (IOErrorIsPermanent(err)) {
                throw std::runtime_error(strprintf("recv(): %s", NetworkErrorString(err)));
            }
            break;
        }
        case 0:
            throw std::runtime_error("Connection unexpectedly closed by peer");
        default:
            auto end = buf + peek_ret;
            auto terminator_pos = std::find(buf, end, terminator);
            terminator_found = terminator_pos != end;

            const size_t try_len{terminator_found ? terminator_pos - buf + 1 :
                                                    static_cast<size_t>(peek_ret)};

            const ssize_t read_ret{Recv(buf, try_len, 0)};

            if (read_ret < 0 || static_cast<size_t>(read_ret) != try_len) {
                throw std::runtime_error(
                    strprintf("recv() returned %u bytes on attempt to read %u bytes but previous "
                              "peek claimed %u bytes are available",
                              read_ret, try_len, peek_ret));
            }

            // Don't include the terminator in the output.
            const size_t append_len{terminator_found ? try_len - 1 : try_len};

            data.append(buf, buf + append_len);

            if (terminator_found) {
                return data;
            }
        }

        const auto now = GetTime<std::chrono::milliseconds>();

        if (now >= deadline) {
            throw std::runtime_error(strprintf(
                "Receive timeout (received %u bytes without terminator before that)", data.size()));
        }

        if (interrupt) {
            throw std::runtime_error(strprintf(
                "Receive interrupted (received %u bytes without terminator before that)",
                data.size()));
        }

        // Wait for a short while (or the socket to become ready for reading) before retrying.
        const auto wait_time = std::min(deadline - now, std::chrono::milliseconds{MAX_WAIT_FOR_IO});
        (void)Wait(wait_time, RECV);
    }
}

bool Sock::IsConnected(std::string& errmsg) const
{
    if (m_socket == INVALID_SOCKET) {
        errmsg = "not connected";
        return false;
    }

    char c;
    switch (Recv(&c, sizeof(c), MSG_PEEK)) {
    case -1: {
        const int err = WSAGetLastError();
        if (IOErrorIsPermanent(err)) {
            errmsg = NetworkErrorString(err);
            return false;
        }
        return true;
    }
    case 0:
        errmsg = "closed";
        return false;
    default:
        return true;
    }
}

void Sock::Close()
{
    if (m_socket == INVALID_SOCKET) {
        return;
    }
#ifdef WIN32
    int ret = closesocket(m_socket);
#else
    int ret = close(m_socket);
#endif
    if (ret) {
        LogPrintf("Error closing socket %d: %s\n", m_socket, NetworkErrorString(WSAGetLastError()));
    }
    m_socket = INVALID_SOCKET;
}

#ifdef WIN32
std::string NetworkErrorString(int err)
{
    wchar_t buf[256];
    buf[0] = 0;
    if(FormatMessageW(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS | FORMAT_MESSAGE_MAX_WIDTH_MASK,
            nullptr, err, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
            buf, ARRAYSIZE(buf), nullptr))
    {
        return strprintf("%s (%d)", std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>,wchar_t>().to_bytes(buf), err);
    }
    else
    {
        return strprintf("Unknown error (%d)", err);
    }
}
#else
std::string NetworkErrorString(int err)
{
    // On BSD sockets implementations, NetworkErrorString is the same as SysErrorString.
    return SysErrorString(err);
}
#endif