From 6940ab33b5009b79c3141dde7f98ea78a2662449 Mon Sep 17 00:00:00 2001
From: Sebastien Braun
Date: Mon, 12 Jul 2010 04:15:13 +0200
Subject: Implement multicast transfer protocol.

---
 src/net/mcast/McastReceiver.cpp | 138 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 138 insertions(+)
 create mode 100644 src/net/mcast/McastReceiver.cpp

(limited to 'src/net/mcast/McastReceiver.cpp')

diff --git a/src/net/mcast/McastReceiver.cpp b/src/net/mcast/McastReceiver.cpp
new file mode 100644
index 0000000..7480ac2
--- /dev/null
+++ b/src/net/mcast/McastReceiver.cpp
@@ -0,0 +1,138 @@
+/*
+# Copyright (c) 2009 - OpenSLX Project, Computer Center University of Freiburg
+#
+# This program is free software distributed under the GPL version 2.
+# See http://openslx.org/COPYING
+#
+# If you have any feedback please consult http://openslx.org/feedback and
+# send your suggestions, praise, or complaints to feedback@openslx.org
+#
+# General information about OpenSLX can be found at http://openslx.org/
+# -----------------------------------------------------------------------------
+# src/net/mcast/McastReceiver.h
+#    - implement the receiver-side multicast file transfer protocol -- implementation
+# -----------------------------------------------------------------------------
+*/
+
+#include <QDataStream>
+#include <QtDebug>
+#include <QtGlobal>
+
+#include <pgm/pgm.h>
+// OpenPGM #defines bool. This is bad in C++.
+#undef bool
+
+#include "McastConstants.h"
+#include "McastReceiver.h"
+
+McastReceiver::McastReceiver(QIODevice* iodev, McastConfiguration* config, QObject* parent) :
+    QObject(parent),
+    _config(config ? new McastConfiguration(*config) : new McastConfiguration()),
+    _socket(0),
+    _curoffs(0),
+    _closed(false),
+    _hash(QCryptographicHash::Md5),
+    _iodev(iodev)
+{
+    _config->setParent(this);
+}
+
+McastReceiver::~McastReceiver()
+{
+    if (_config)
+        delete _config;
+}
+
+void McastReceiver::start()
+{
+    _socket = new McastPGMSocket(this);
+    connect(_socket, SIGNAL(receivedPacket(QByteArray)), this, SLOT(receivedPacket(QByteArray)));
+    connect(_socket, SIGNAL(connectionReset()), this, SLOT(connectionReset()));
+    // connect(_socket, SIGNAL(connectionFinished()), this, SLOT(connectionFinished()));
+    _socket->open(_config, McastPGMSocket::PSOCK_READ);
+}
+
+void McastReceiver::receivedPacket(QByteArray const& bytes)
+{
+    if(_closed)
+        return;
+
+    quint16 checksum_should = qChecksum(bytes.constData(), bytes.size() - 2);
+
+    QDataStream strm(bytes);
+    strm.setByteOrder(QDataStream::BigEndian);
+
+    // read the packet
+    quint64 magic;
+    quint64 offset;
+    quint16 checksum;
+
+
+    strm >> magic;
+    if(magic != MCASTFT_MAGIC)
+    {
+        qCritical() << "Received packet whose magic number does not match. Ignoring.";
+        return;
+    }
+
+    strm >> offset;
+    qDebug() << " Received packet for offset" << offset;
+
+    if (offset == UINT64_C(0xffffffffffffffff))
+    {
+        // this is the end of the data stream.
+        QByteArray md5;
+        strm >> md5;
+
+        quint16 fchecksum;
+        strm >> fchecksum;
+
+        // compare the hash value
+        if ((fchecksum != checksum_should) || (md5 != _hash.result()))
+        {
+            _close(RES_MD5_MISMATCH);
+        }
+        else
+        {
+            _close(RES_OK);
+        }
+
+        return;
+    }
+    else if (offset != _curoffs)
+    {
+        qCritical() << "Packet loss or double delivery. PGM should have prevented this. Bailing out.";
+        _close(RES_OFFSET_MISMATCH);
+        return;
+    }
+
+    QByteArray contents;
+    strm >> contents;
+    _curoffs += contents.size();
+
+    strm >> checksum;
+    if(checksum != checksum_should)
+    {
+        qCritical() << "Checksum does not match. Bailing out.";
+        _close(RES_CHECKSUM_MISMATCH);
+        return;
+    }
+
+    _hash.addData(contents);
+
+    _iodev->write(contents);
+}
+
+void McastReceiver::connectionReset()
+{
+    _close(RES_CONNECTION_RESET);
+}
+
+void McastReceiver::_close(Result result)
+{
+	_iodev->close();
+	_socket->finish();
+
+    _closed = true;
+    emit finished(result);
+}
-- 
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