Device Emulation (contd.): Assign a random mac address to a DeviceGroup at alloc time to ensure unique device keys when enumerating devices from device groups

client/devicegroupdialog.cpp

@@ -250,22 +250,8 @@ void DeviceGroupDialog::loadDeviceGroup()
     devicePerVlanCount->setValue(devGrp->device_count());
 
     OstEmul::MacEmulation mac = devGrp->GetExtension(OstEmul::mac);
-    if (!mac.has_address()) {
-        // Mac address as per RFC 4814 Sec 4.2
-        // (RR & 0xFC):PP:PP:RR:RR:RR
-        // where RR is a random number, PP:PP is 1-indexed port index
-        // NOTE: although qrand() return type is a int, the max value
-        // is RAND_MAX (stdlib.h) which is often 16-bit only, so we
-        // use two random numbers
-        quint32 r1 = qrand(), r2 = qrand();
-        quint64 mac;
-        mac = quint64(r1 & 0xfc00) << 32
-            | quint64(port_->id() + 1) << 24
-            | quint64((r1 & 0xff) << 16 | (r2 & 0xffff));
-        macAddress->setValue(mac);
-    }
-    else
-        macAddress->setValue(mac.address());
+    Q_ASSERT(mac.has_address());
+    macAddress->setValue(mac.address());
     macStep->setValue(mac.step());
 
     OstEmul::Ip4Emulation ip4 = devGrp->GetExtension(OstEmul::ip4);

client/main.cpp

@@ -25,8 +25,10 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>
 #include "settings.h"
 
 #include <QApplication>
+#include <QDateTime>
 #include <QFile>
 #include <QSettings>
+#include <QtGlobal>
 
 #include <google/protobuf/stubs/common.h>
 
@@ -68,6 +70,7 @@ int main(int argc, char* argv[])
         appSettings->value(kAwkPathKey, kAwkPathDefaultValue).toString());
 
     Preferences::initDefaults();
+    qsrand(QDateTime::currentDateTime().toTime_t());
 
     mainWindow = new MainWindow;
     mainWindow->show();

client/port.cpp

@@ -20,6 +20,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>
 #include "port.h"
 
 #include "abstractfileformat.h"
+#include "emulation.h"
 
 #include <QApplication>
 #include <QMainWindow>
@@ -702,7 +703,7 @@ bool Port::newDeviceGroupAt(int index, const OstProto::DeviceGroup *deviceGroup)
     if (index < 0 || index > numDeviceGroups())
         return false;
 
-    OstProto::DeviceGroup *devGrp = new OstProto::DeviceGroup;
+    OstProto::DeviceGroup *devGrp = newDeviceGroup(id());
 
     if (!devGrp) {
         qWarning("failed allocating a new device group");
@@ -738,7 +739,7 @@ bool Port::insertDeviceGroup(uint deviceGroupId)
         return false;
     }
 
-    devGrp = new OstProto::DeviceGroup;
+    devGrp = newDeviceGroup(id());
     devGrp->mutable_device_group_id()->set_id(deviceGroupId);
     deviceGroups_.append(devGrp);
 

common/emulation.h

@@ -0,0 +1,55 @@
+/*
+Copyright (C) 2016 Srivats P.
+
+This file is part of "Ostinato"
+
+This 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, either version 3 of the License, or
+(at your option) any later version.
+
+This program 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 this program.  If not, see <http://www.gnu.org/licenses/>
+*/
+
+#ifndef _EMULATION_H
+#define _EMULATION_H
+
+#include "emulproto.pb.h"
+
+#include <QtGlobal>
+
+static inline OstProto::DeviceGroup* newDeviceGroup(uint portId)
+{
+    OstProto::DeviceGroup *devGrp = new OstProto::DeviceGroup;
+
+    // To ensure that DeviceGroup have a unique key, we assign
+    // a random mac address upon creation; ideally, it would
+    // have been good to inherit OstProto::DeviceGroup and define
+    // a new constructor, but ProtoBuf forbids against inheriting
+    // generated classes, so we use this helper function instead
+    //
+    // Create a mac address as per RFC 4814 Sec 4.2
+    // (RR & 0xFC):PP:PP:RR:RR:RR
+    // where RR is a random number, PP:PP is 1-indexed port index
+    // NOTE: although qrand() return type is a int, the max value
+    // is RAND_MAX (stdlib.h) which is often 16-bit only, so we
+    // use two random numbers
+    quint32 r1 = qrand(), r2 = qrand();
+    quint64 mac;
+    mac = quint64(r1 & 0xfc00) << 32
+        | quint64(portId + 1) << 24
+        | quint64((r1 & 0xff) << 16 | (r2 & 0xffff));
+    devGrp->MutableExtension(OstEmul::mac)->set_address(mac);
+
+    return devGrp;
+}
+
+
+#endif
+

rpc/rpcconn.cpp

@@ -28,6 +28,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>
 #include <google/protobuf/service.h>
 #include <google/protobuf/io/zero_copy_stream_impl.h>
 
+#include <QDateTime>
 #include <QHostAddress>
 #include <QString>
 #include <QTcpSocket>
@@ -82,6 +83,7 @@ void RpcConnection::start()
         return;
     }
     qDebug("clientSock Thread = %p", clientSock->thread());
+    qsrand(QDateTime::currentDateTime().toTime_t());
 
     connId.setLocalData(new QString(id.arg(clientSock->peerAddress().toString())
                                       .arg(clientSock->peerPort())));

server/devicemanager.cpp

@@ -21,6 +21,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>
 
 #include "abstractport.h"
 #include "device.h"
+#include "../common/emulation.h"
 #include "packetbuffer.h"
 
 #include "../common/emulproto.pb.h"
@@ -93,7 +94,7 @@ bool DeviceManager::addDeviceGroup(uint deviceGroupId)
         return false;
     }
 
-    deviceGroup = new OstProto::DeviceGroup;
+    deviceGroup = newDeviceGroup(port_->id());
     deviceGroup->mutable_device_group_id()->set_id(deviceGroupId);
     deviceGroupList_.insert(deviceGroupId, deviceGroup);