From afc69ca4ffb0e11d9d06b8ddd31ee40963f86f17 Mon Sep 17 00:00:00 2001
From: Manuel Schneider
Date: Wed, 28 May 2014 00:37:28 +0200
Subject: Outsource serverDiscovery.

---
 src/client/net/serverdiscovery.cpp | 181 +++++++++++++++++++++++++++++++++++++
 1 file changed, 181 insertions(+)
 create mode 100644 src/client/net/serverdiscovery.cpp

(limited to 'src/client/net/serverdiscovery.cpp')

diff --git a/src/client/net/serverdiscovery.cpp b/src/client/net/serverdiscovery.cpp
new file mode 100644
index 0000000..9f1991c
--- /dev/null
+++ b/src/client/net/serverdiscovery.cpp
@@ -0,0 +1,181 @@
+
+#include <QNetworkInterface>
+#include "../../shared/settings.h"
+#include "../../shared/network.h"
+#include "../../shared/util.h"
+#include "serverdiscovery.h"
+#include <assert.h>
+
+
+/***************************************************************************//**
+ * Ctor
+ */
+ServerDiscovery::ServerDiscovery(QObject *parent) :	QObject(parent)
+{
+	_hashErrorCount = 0;
+	_ipErrorCount = 0;
+
+	/* Try to get a UDP port for server discovery */
+	int tries = 10;
+	while (tries-- != 0)
+	{
+		const quint16 port = (quint16)(qrand() % 10000) + 10000;
+		if (_discoverySocket.bind(QHostAddress::Any, port))
+			break;
+		if (tries == 0)
+			qFatal("Could not bind to any UDP port for server discovery.");
+	}
+	// Handle incoming messages
+	connect(&_discoverySocket, SIGNAL(readyRead()), this, SLOT(onUdpReadyRead()));
+
+	/* Setup the discovery timer */
+	_discoveryTimer.setInterval(500);
+	_discoveryTimer.setSingleShot(true);
+	//
+	connect(&_discoveryTimer, SIGNAL(timeout()), this, SLOT(doDiscovery()));
+}
+
+/***************************************************************************//**
+ * Dtor
+ */
+ServerDiscovery::~ServerDiscovery()
+{
+}
+
+/***************************************************************************//**
+ * @brief start
+ */
+void ServerDiscovery::start(const QByteArray& sessionName)
+{
+	assert(!this->isActive());
+
+	// Set the session which is searched
+	_nameBytes = sessionName;
+
+	// Enable signal emittance
+	this->blockSignals(false);
+
+	// Reset the error counters
+	_hashErrorCount = _ipErrorCount = 0;
+
+	// reset anbd start the discovery timer
+	_discoveryTimer.setInterval(500);
+	_discoveryTimer.start();
+}
+
+/***************************************************************************//**
+ * @brief stop
+ */
+void ServerDiscovery::stop()
+{
+	assert(this->isActive());
+
+	//Bock further signal emittance
+	this->blockSignals(true);
+	_discoveryTimer.stop();
+}
+
+/*******************************************************************************
+ * SLOTS
+ ***************************************************************************//**
+ * @brief ConnectWindow::doDiscovery
+ */
+void ServerDiscovery::doDiscovery()
+{
+	// Send discovery
+	_packet.reset();
+	QByteArray iplist(Network::interfaceAddressesToString().toUtf8());
+	// qDebug
+	QByteArray salt1(SALT_LEN, 0);
+	if (_salt2.size() < SALT_LEN)
+		_salt2.resize(SALT_LEN);
+	for (int i = 0; i < SALT_LEN; ++i) {
+		salt1[i] = qrand() & 0xff;
+		_salt2[i] = qrand() & 0xff;
+	}
+	_packet.reset();
+	_packet.setField(_HASH, genSha1(&_nameBytes, &salt1, &iplist));
+	_packet.setField(_SALT1, salt1);
+	_packet.setField(_SALT2, _salt2);
+	_packet.setField(_IPLIST, iplist);
+	foreach (QNetworkInterface interface, QNetworkInterface::allInterfaces())
+	{
+		foreach (QNetworkAddressEntry entry, interface.addressEntries())
+		{
+			if (!entry.broadcast().isNull() && entry.ip() != QHostAddress::LocalHost && entry.ip() != QHostAddress::LocalHostIPv6)
+			{
+				qDebug() << "Broadcasting to " << entry.broadcast().toString();
+				if (!_packet.writeMessage(&_discoverySocket, entry.broadcast(), SERVICE_DISCOVERY_PORT))
+					qDebug("FAILED");
+			}
+		}
+	}
+	qDebug("Broadcasting to 255.255.255.255");
+	if (!_packet.writeMessage(&_discoverySocket, QHostAddress::Broadcast, SERVICE_DISCOVERY_PORT))
+		qDebug("FAILED");
+
+	// Start the timer again with a larger interval
+	if (_discoveryTimer.interval() < 5000)
+		_discoveryTimer.setInterval(_discoveryTimer.interval() * 2);
+	_discoveryTimer.start();
+}
+
+
+/***************************************************************************//**
+ * Handle incoming service discovery packets.
+ */
+void ServerDiscovery::onUdpReadyRead()
+{
+	char data[UDPBUFSIZ];
+	QHostAddress addr;
+	quint16 port;
+	while (_discoverySocket.hasPendingDatagrams())
+	{
+		// Discard any packets if discovery is stopped
+		if (!this->isActive()){
+			_discoverySocket.readDatagram(NULL, 0);
+			continue;
+		}
+
+		const qint64 size = _discoverySocket.readDatagram(data, UDPBUFSIZ, &addr, &port);
+		if (size <= 0) //|| _connection != NULL) // TODO CHECK
+			continue;
+
+		_packet.reset();
+		if (!_packet.readMessage(data, (quint32)size))
+			continue;
+
+		// Valid packet, process it:
+		const QByteArray hash(_packet.getFieldBytes(_HASH));
+		const QByteArray iplist(_packet.getFieldBytes(_IPLIST));
+		const QByteArray port(_packet.getFieldBytes(_PORT));
+		const QByteArray cert(_packet.getFieldBytes(_CERT));
+
+		// Check if the source IP of the packet matches any of the addresses given in the IP list
+		if (!Network::isAddressInList(QString::fromUtf8(iplist), addr.toString()))
+		{
+			++_ipErrorCount;
+			emit error(ErrorType::InvalidIpList, _hashErrorCount);
+			continue;
+		}
+
+		// If so, check if the submitted hash seems valid
+		if (genSha1(&_nameBytes, &_salt2, &iplist, &port, &cert) != hash)
+		{
+			// did not match local session name, or other data was spoofed
+			++_hashErrorCount;
+			emit error(ErrorType::InvalidHash, _ipErrorCount);
+			continue;
+		}
+
+		/* Otherwise it's a valid reply */
+		qDebug() << "Server detected:"
+				<< addr.toString() + ":" + QString::fromUtf8(port) + "/" + _nameBytes;
+
+		// Tell that a server hs been found
+		emit serverDetected(addr.toString(), (quint16)QString::fromUtf8(port).toInt(), _nameBytes, cert);
+
+		// Stop the discovery
+		this->stop();
+	}
+}
-- 
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