Remove protected field m_DeviceOpened from IDevice interface. (#1961)

* Remove protected field `m_DeviceOpened` from `IDevice` interface.

The C++ core guidelines recommend against usages of protected fields, due to the maintainability issues in large class hierarchies.
As `IDevice` is the base interface of every device, it is better to let concrete implementations handle their own state detection than to force a boolean to be used everywhere.
A `PCapLiveDevice` for instance, can instead use the state of its `PcapHandle` for state detection.

* Add `isOpened` to XDP device.

* Change IDevice destructor to `= default`.

Author: Dimi1010

Pcap++/header/Device.h

@@ -19,15 +19,11 @@ namespace pcpp
 	class IDevice
 	{
 	protected:
-		bool m_DeviceOpened;
-
 		// c'tor should not be public
-		IDevice() : m_DeviceOpened(false)
-		{}
+		IDevice() = default;
 
 	public:
-		virtual ~IDevice()
-		{}
+		virtual ~IDevice() = default;
 
 		/// Open the device
 		/// @return True if device was opened successfully, false otherwise
@@ -37,10 +33,7 @@ namespace pcpp
 		virtual void close() = 0;
 
 		/// @return True if the file is opened, false otherwise
-		inline bool isOpened()
-		{
-			return m_DeviceOpened;
-		}
+		virtual bool isOpened() const = 0;
 	};
 
 	/// @class IFilterableDevice

Pcap++/header/DpdkDevice.h

@@ -731,6 +731,11 @@ namespace pcpp
 		/// Close the DpdkDevice. When device is closed it's not possible work with it
 		void close() override;
 
+		bool isOpened() const override
+		{
+			return m_DeviceOpened;
+		}
+
 	private:
 		struct DpdkCoreConfiguration
 		{
@@ -769,6 +774,8 @@ namespace pcpp
 		uint64_t convertRssHfToDpdkRssHf(uint64_t rssHF) const;
 		uint64_t convertDpdkRssHfToRssHf(uint64_t dpdkRssHF) const;
 
+		bool m_DeviceOpened = false;
+
 		std::string m_DeviceName;
 		DpdkPMDType m_PMDType;
 		std::string m_PMDName;

Pcap++/header/KniDevice.h

@@ -524,7 +524,14 @@ namespace pcpp
 		/// Stops asynchronous packet capture if it is running.
 		void close();
 
+		bool isOpened() const override
+		{
+			return m_DeviceOpened;
+		}
+
 	private:
+		bool m_DeviceOpened = false;
+
 		struct rte_kni* m_Device;
 		struct rte_mempool* m_MBufMempool;
 		struct KniDeviceInfo

Pcap++/header/PcapFileDevice.h

@@ -39,6 +39,7 @@ namespace pcpp
 	class IFileDevice : public IPcapDevice
 	{
 	protected:
+		bool m_DeviceOpened = false;
 		std::string m_FileName;
 
 		explicit IFileDevice(const std::string& fileName);
@@ -53,6 +54,11 @@ namespace pcpp
 		/// Close the file
 		void close() override;
 
+		bool isOpened() const override
+		{
+			return m_DeviceOpened;
+		}
+
 		/// @brief Get the statistics for this device.
 		///
 		/// The PcapStats structure will hold the following:

Pcap++/header/PcapLiveDevice.h

@@ -120,6 +120,8 @@ namespace pcpp
 			std::thread m_WorkerThread;
 		};
 
+		bool m_DeviceOpened = false;
+
 		// This is a second descriptor for the same device. It is needed because of a bug
 		// that occurs in libpcap on Linux (on Windows using WinPcap/Npcap it works well):
 		// It's impossible to capture packets sent by the same descriptor
@@ -653,6 +655,11 @@ namespace pcpp
 
 		void close() override;
 
+		bool isOpened() const override
+		{
+			return m_DeviceOpened;
+		}
+
 		/// Clones the current device class
 		/// @return Pointer to the copied class
 		virtual PcapLiveDevice* clone() const;

Pcap++/header/PfRingDevice.h

@@ -59,6 +59,8 @@ namespace pcpp
 			bool m_Ready = false;
 		};
 
+		bool m_DeviceOpened = false;
+
 		std::vector<pfring*> m_PfRingDescriptors;
 		std::string m_DeviceName;
 		int m_InterfaceIndex;
@@ -308,6 +310,11 @@ namespace pcpp
 		/// Closes all RX channels currently opened in device
 		void close();
 
+		bool isOpened() const override
+		{
+			return m_DeviceOpened;
+		}
+
 		using IFilterableDevice::setFilter;
 
 		/// Sets a BPF filter to the device

Pcap++/header/RawSocketDevice.h

@@ -124,6 +124,11 @@ namespace pcpp
 		/// Close the raw socket
 		void close() override;
 
+		bool isOpened() const override
+		{
+			return m_DeviceOpened;
+		}
+
 	private:
 		enum SocketFamily
 		{
@@ -132,6 +137,8 @@ namespace pcpp
 			IPv6 = 2
 		};
 
+		bool m_DeviceOpened = false;
+
 		SocketFamily m_SockFamily;
 		void* m_Socket;
 		IPAddress m_InterfaceIP;

Pcap++/header/XdpDevice.h

@@ -179,6 +179,11 @@ namespace pcpp
 		/// Close the device. This method closes the AF_XDP socket and frees the UMEM that was allocated for it.
 		void close() override;
 
+		bool isOpened() const override
+		{
+			return m_DeviceOpened;
+		}
+
 		/// Start receiving packets. In order to use this method the device should be open. Note that this method is
 		/// blocking and will return if:
 		/// - stopReceivePackets() was called from within the user callback
@@ -285,6 +290,8 @@ namespace pcpp
 			uint64_t txCompletedPackets;
 		};
 
+		bool m_DeviceOpened = false;
+
 		std::string m_InterfaceName;
 		XdpDeviceConfiguration* m_Config;
 		bool m_ReceivingPackets;

Pcap++/src/PcapDevice.cpp

@@ -136,7 +136,7 @@ namespace pcpp
 	bool IPcapDevice::setFilter(std::string filterAsString)
 	{
 		PCPP_LOG_DEBUG("Filter to be set: '" << filterAsString << "'");
-		if (!m_DeviceOpened)
+		if (!isOpened())
 		{
 			PCPP_LOG_ERROR("Device not Opened!! cannot set filter");
 			return false;