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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547
|
/****************************************************************************
**
** Copyright (C) 2016 Alex Trotsenko <alex1973tr@gmail.com>
** Contact: https://www.qt.io/licensing/
**
** This file is part of the QtNetwork module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 3 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL3 included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 3 requirements
** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 2.0 or (at your option) the GNU General
** Public license version 3 or any later version approved by the KDE Free
** Qt Foundation. The licenses are as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
** be met: https://www.gnu.org/licenses/gpl-2.0.html and
** https://www.gnu.org/licenses/gpl-3.0.html.
**
** $QT_END_LICENSE$
**
****************************************************************************/
//#define QSCTPSOCKET_DEBUG
/*!
\class QSctpSocket
\since 5.8
\brief The QSctpSocket class provides an SCTP socket.
\ingroup network
\inmodule QtNetwork
SCTP (Stream Control Transmission Protocol) is a transport layer
protocol serving in a similar role as the popular protocols TCP
and UDP. Like UDP, SCTP is message-oriented, but it ensures reliable,
in-sequence transport of messages with congestion control like
TCP.
SCTP is connection-oriented protocol, which provides the complete
simultaneous transmission of multiple data streams between
endpoints. This multi-streaming allows data to be delivered by
independent channels, so that if there is data loss in one stream,
delivery will not be affected for the other streams.
Being message-oriented, SCTP transports a sequence of messages,
rather than transporting an unbroken stream of bytes as does TCP.
Like in UDP, in SCTP a sender sends a message in one operation,
and that exact message is passed to the receiving application
process in one operation. But unlike UDP, the delivery is
guaranteed.
It also supports multi-homing, meaning that a connected endpoint
can have alternate IP addresses associated with it in order to
route around network failure or changing conditions.
QSctpSocket is a convenience subclass of QTcpSocket that allows
you to emulate TCP data stream over SCTP or establish an SCTP
connection for reliable datagram service.
QSctpSocket can operate in one of two possible modes:
\list
\li Continuous byte stream (TCP emulation).
\li Multi-streamed datagram mode.
\endlist
To set a continuous byte stream mode, instantiate QSctpSocket and
call setMaximumChannelCount() with a negative value. This gives the
ability to use QSctpSocket as a regular buffered QTcpSocket. You
can call connectToHost() to initiate connection with endpoint,
write() to transmit and read() to receive data from the peer, but
you cannot distinguish message boundaries.
By default, QSctpSocket operates in datagram mode. Before
connecting, call setMaximumChannelCount() to set the maximum number of
channels that the application is prepared to support. This number
is a parameter negotiated with the remote endpoint and its value
can be bounded by the operating system. The default value of 0
indicates to use the peer's value. If both endpoints have default
values, then number of connection channels is system-dependent.
After establishing a connection, you can fetch the actual number
of channels by calling readChannelCount() and writeChannelCount().
\snippet code/src_network_socket_qsctpsocket.cpp 0
In datagram mode, QSctpSocket performs the buffering of datagrams
independently for each channel. You can queue a datagram to the
buffer of the current channel by calling writeDatagram() and read
a pending datagram by calling readDatagram() respectively.
Using the standard QIODevice functions read(), readLine(), write(),
etc. is allowed in datagram mode with the same limitations as in
continuous byte stream mode.
\note This feature is not supported on the Windows platform.
\sa QSctpServer, QTcpSocket, QAbstractSocket
*/
#include "qsctpsocket.h"
#include "qsctpsocket_p.h"
#include "qabstractsocketengine_p.h"
#include "private/qbytearray_p.h"
#ifdef QSCTPSOCKET_DEBUG
#include <qdebug.h>
#endif
QT_BEGIN_NAMESPACE
/*! \internal
*/
QSctpSocketPrivate::QSctpSocketPrivate()
: maximumChannelCount(0)
{
}
/*! \internal
*/
QSctpSocketPrivate::~QSctpSocketPrivate()
{
}
/*! \internal
*/
bool QSctpSocketPrivate::canReadNotification()
{
Q_Q(QSctpSocket);
#if defined (QSCTPSOCKET_DEBUG)
qDebug("QSctpSocketPrivate::canReadNotification()");
#endif
// Handle TCP emulation mode in the base implementation.
if (!q->isInDatagramMode())
return QTcpSocketPrivate::canReadNotification();
const int savedCurrentChannel = currentReadChannel;
bool currentChannelRead = false;
do {
int datagramSize = incomingDatagram.size();
QIpPacketHeader header;
do {
// Determine the size of the pending datagram.
qint64 bytesToRead = socketEngine->bytesAvailable();
if (bytesToRead == 0) {
// As a corner case, if we can't determine the size of the pending datagram,
// try to read 4K of data from the socket. Subsequent ::recvmsg call either
// fails or returns the actual length of the datagram.
bytesToRead = 4096;
}
Q_ASSERT((datagramSize + int(bytesToRead)) < MaxByteArraySize);
incomingDatagram.resize(datagramSize + int(bytesToRead));
#if defined (QSCTPSOCKET_DEBUG)
qDebug("QSctpSocketPrivate::canReadNotification() about to read %lli bytes",
bytesToRead);
#endif
qint64 readBytes = socketEngine->readDatagram(
incomingDatagram.data() + datagramSize, bytesToRead, &header,
QAbstractSocketEngine::WantAll);
if (readBytes <= 0) {
if (readBytes == -2) { // no data available for reading
incomingDatagram.resize(datagramSize);
return currentChannelRead;
}
socketEngine->close();
if (readBytes == 0) {
setErrorAndEmit(QAbstractSocket::RemoteHostClosedError,
QSctpSocket::tr("The remote host closed the connection"));
} else {
#if defined (QSCTPSOCKET_DEBUG)
qDebug("QSctpSocketPrivate::canReadNotification() read failed: %s",
socketEngine->errorString().toLatin1().constData());
#endif
setErrorAndEmit(socketEngine->error(), socketEngine->errorString());
}
#if defined (QSCTPSOCKET_DEBUG)
qDebug("QSctpSocketPrivate::canReadNotification() disconnecting socket");
#endif
q->disconnectFromHost();
return currentChannelRead;
}
datagramSize += int(readBytes); // update datagram size
} while (!header.endOfRecord);
#if defined (QSCTPSOCKET_DEBUG)
qDebug("QSctpSocketPrivate::canReadNotification() got datagram from channel %i, size = %i",
header.streamNumber, datagramSize);
#endif
// Drop the datagram, if opened only for writing
if (!q->isReadable()) {
incomingDatagram.clear();
continue;
}
// Store datagram in the channel buffer
Q_ASSERT(header.streamNumber < readBuffers.size());
incomingDatagram.resize(datagramSize);
readBuffers[header.streamNumber].setChunkSize(0); // set packet mode on channel buffer
readBuffers[header.streamNumber].append(incomingDatagram);
incomingDatagram = QByteArray();
if (readHeaders.size() != readBuffers.size())
readHeaders.resize(readBuffers.size());
readHeaders[header.streamNumber].push_back(header);
// Emit notifications.
if (header.streamNumber == savedCurrentChannel)
currentChannelRead = true;
emitReadyRead(header.streamNumber);
} while (state == QAbstractSocket::ConnectedState);
return currentChannelRead;
}
/*! \internal
*/
bool QSctpSocketPrivate::writeToSocket()
{
Q_Q(QSctpSocket);
#if defined (QSCTPSOCKET_DEBUG)
qDebug("QSctpSocketPrivate::writeToSocket()");
#endif
// Handle TCP emulation mode in the base implementation.
if (!q->isInDatagramMode())
return QTcpSocketPrivate::writeToSocket();
if (!socketEngine)
return false;
QIpPacketHeader defaultHeader;
const int savedCurrentChannel = currentWriteChannel;
bool currentChannelWritten = false;
bool transmitting;
do {
transmitting = false;
for (int channel = 0; channel < writeBuffers.size(); ++channel) {
QRingBuffer &channelBuffer = writeBuffers[channel];
if (channelBuffer.isEmpty())
continue;
const bool hasHeader = (channel < writeHeaders.size())
&& !writeHeaders[channel].empty();
QIpPacketHeader &header = hasHeader ? writeHeaders[channel].front() : defaultHeader;
header.streamNumber = channel;
qint64 sent = socketEngine->writeDatagram(channelBuffer.readPointer(),
channelBuffer.nextDataBlockSize(),
header);
if (sent < 0) {
if (sent == -2) // temporary error in writeDatagram
return currentChannelWritten;
socketEngine->close();
#if defined (QSCTPSOCKET_DEBUG)
qDebug("QSctpSocketPrivate::writeToSocket() write error, aborting. %s",
socketEngine->errorString().toLatin1().constData());
#endif
setErrorAndEmit(socketEngine->error(), socketEngine->errorString());
// An unexpected error so close the socket.
q->disconnectFromHost();
return currentChannelWritten;
}
Q_ASSERT(sent == channelBuffer.nextDataBlockSize());
#if defined (QSCTPSOCKET_DEBUG)
qDebug("QSctpSocketPrivate::writeToSocket() sent datagram of size %lli to channel %i",
sent, channel);
#endif
transmitting = true;
// Remove datagram from the buffer
channelBuffer.read();
if (hasHeader)
writeHeaders[channel].pop_front();
// Emit notifications.
if (channel == savedCurrentChannel)
currentChannelWritten = true;
emitBytesWritten(sent, channel);
// If we were closed as a result of the bytesWritten() signal, return.
if (state == QAbstractSocket::UnconnectedState) {
#if defined (QSCTPSOCKET_DEBUG)
qDebug("QSctpSocketPrivate::writeToSocket() socket is closing - returning");
#endif
return currentChannelWritten;
}
}
} while (transmitting);
// At this point socket is either in Connected or Closing state,
// write buffers are empty.
if (state == QAbstractSocket::ClosingState)
q->disconnectFromHost();
else
socketEngine->setWriteNotificationEnabled(false);
return currentChannelWritten;
}
/*! \internal
*/
void QSctpSocketPrivate::configureCreatedSocket()
{
if (socketEngine)
socketEngine->setOption(QAbstractSocketEngine::MaxStreamsSocketOption,
maximumChannelCount < 0 ? 1 : maximumChannelCount);
}
/*!
Creates a QSctpSocket object in state \c UnconnectedState.
Sets the datagram operation mode. The \a parent argument is passed
to QObject's constructor.
\sa socketType(), setMaximumChannelCount()
*/
QSctpSocket::QSctpSocket(QObject *parent)
: QTcpSocket(SctpSocket, *new QSctpSocketPrivate, parent)
{
#if defined(QSCTPSOCKET_DEBUG)
qDebug("QSctpSocket::QSctpSocket()");
#endif
d_func()->isBuffered = true;
}
/*!
Destroys the socket, closing the connection if necessary.
\sa close()
*/
QSctpSocket::~QSctpSocket()
{
#if defined(QSCTPSOCKET_DEBUG)
qDebug("QSctpSocket::~QSctpSocket()");
#endif
}
/*! \reimp
*/
qint64 QSctpSocket::readData(char *data, qint64 maxSize)
{
Q_D(QSctpSocket);
// Cleanup headers, if the user calls the standard QIODevice functions
if (d->currentReadChannel < d->readHeaders.size())
d->readHeaders[d->currentReadChannel].clear();
return QTcpSocket::readData(data, maxSize);
}
/*! \reimp
*/
qint64 QSctpSocket::readLineData(char *data, qint64 maxlen)
{
Q_D(QSctpSocket);
// Cleanup headers, if the user calls the standard QIODevice functions
if (d->currentReadChannel < d->readHeaders.size())
d->readHeaders[d->currentReadChannel].clear();
return QTcpSocket::readLineData(data, maxlen);
}
/*! \reimp
*/
void QSctpSocket::close()
{
QTcpSocket::close();
d_func()->readHeaders.clear();
}
/*! \reimp
*/
void QSctpSocket::disconnectFromHost()
{
Q_D(QSctpSocket);
QTcpSocket::disconnectFromHost();
if (d->state == QAbstractSocket::UnconnectedState) {
d->incomingDatagram.clear();
d->writeHeaders.clear();
}
}
/*!
Sets the maximum number of channels that the application is
prepared to support in datagram mode, to \a count. If \a count
is 0, endpoint's value for maximum number of channels is used.
Negative \a count sets a continuous byte stream mode.
Call this method only when QSctpSocket is in UnconnectedState.
\sa maximumChannelCount(), readChannelCount(), writeChannelCount()
*/
void QSctpSocket::setMaximumChannelCount(int count)
{
Q_D(QSctpSocket);
if (d->state != QAbstractSocket::UnconnectedState) {
qWarning("QSctpSocket::setMaximumChannelCount() is only allowed in UnconnectedState");
return;
}
#if defined(QSCTPSOCKET_DEBUG)
qDebug("QSctpSocket::setMaximumChannelCount(%i)", count);
#endif
d->maximumChannelCount = qMax(count, -1);
}
/*!
Returns the maximum number of channels that QSctpSocket is able to
support.
A value of 0 (the default) means that the number of connection
channels would be set by the remote endpoint.
Returns -1 if QSctpSocket is running in continuous byte stream
mode.
\sa setMaximumChannelCount(), readChannelCount(), writeChannelCount()
*/
int QSctpSocket::maximumChannelCount() const
{
return d_func()->maximumChannelCount;
}
/*!
Returns \c true if the socket is running in datagram mode.
\sa setMaximumChannelCount()
*/
bool QSctpSocket::isInDatagramMode() const
{
Q_D(const QSctpSocket);
return d->maximumChannelCount != -1 && d->isBuffered;
}
/*!
Reads a datagram from the buffer of the current read channel, and
returns it as a QNetworkDatagram object, along with the sender's
host address and port. If possible, this function will also try to
determine the datagram's destination address, port, and the number
of hop counts at reception time.
On failure, returns a QNetworkDatagram that reports \l
{QNetworkDatagram::isValid()}{not valid}.
\sa writeDatagram(), isInDatagramMode(), currentReadChannel()
*/
QNetworkDatagram QSctpSocket::readDatagram()
{
Q_D(QSctpSocket);
if (!isReadable() || !isInDatagramMode()) {
qWarning("QSctpSocket::readDatagram(): operation is not permitted");
return QNetworkDatagram();
}
if (d->currentReadChannel >= d->readHeaders.size()
|| d->readHeaders[d->currentReadChannel].size() == 0) {
Q_ASSERT(d->buffer.isEmpty());
return QNetworkDatagram();
}
QNetworkDatagram result(*new QNetworkDatagramPrivate(d->buffer.read(),
d->readHeaders[d->currentReadChannel].front()));
d->readHeaders[d->currentReadChannel].pop_front();
#if defined (QSCTPSOCKET_DEBUG)
qDebug("QSctpSocket::readDatagram() returning datagram (%p, %i, \"%s\", %i)",
result.d->data.constData(),
result.d->data.size(),
result.senderAddress().toString().toLatin1().constData(),
result.senderPort());
#endif
return result;
}
/*!
Writes a \a datagram to the buffer of the current write channel.
Returns true on success; otherwise returns false.
\sa readDatagram(), isInDatagramMode(), currentWriteChannel()
*/
bool QSctpSocket::writeDatagram(const QNetworkDatagram &datagram)
{
Q_D(QSctpSocket);
if (!isWritable() || d->state != QAbstractSocket::ConnectedState || !d->socketEngine
|| !d->socketEngine->isValid() || !isInDatagramMode()) {
qWarning("QSctpSocket::writeDatagram(): operation is not permitted");
return false;
}
if (datagram.d->data.isEmpty()) {
qWarning("QSctpSocket::writeDatagram() is called with empty datagram");
return false;
}
#if defined QSCTPSOCKET_DEBUG
qDebug("QSctpSocket::writeDatagram(%p, %i, \"%s\", %i)",
datagram.d->data.constData(),
datagram.d->data.size(),
datagram.destinationAddress().toString().toLatin1().constData(),
datagram.destinationPort());
#endif
if (d->writeHeaders.size() != d->writeBuffers.size())
d->writeHeaders.resize(d->writeBuffers.size());
Q_ASSERT(d->currentWriteChannel < d->writeHeaders.size());
d->writeHeaders[d->currentWriteChannel].push_back(datagram.d->header);
d->writeBuffer.setChunkSize(0); // set packet mode on channel buffer
d->writeBuffer.append(datagram.d->data);
d->socketEngine->setWriteNotificationEnabled(true);
return true;
}
QT_END_NAMESPACE
|