- add Pcap++ Windows build

pcappp/include/pcapplusplus/PacketTrailerLayer.h

@@ -0,0 +1,84 @@
+#ifndef PACKETPP_PACKET_TRAILER_LAYER
+#define PACKETPP_PACKET_TRAILER_LAYER
+
+/// @file
+
+#include "Layer.h"
+
+namespace pcpp
+{
+	/**
+	 * @class PacketTrailerLayer
+	 * A class for representing packet tailer (a.k.a footer or padding) which refers to supplemental data placed at the end of a block of data
+	 * being stored or transmitted, which may contain information for the handling of the data block, or just mark its end
+	 * (taken from Wikipedia: https://en.wikipedia.org/wiki/Trailer_(computing) )
+	 *
+	 * There are various reasons for adding a packet trailer, one of the most famous is FCS (Frame check sequence) which refers to the extra
+	 * error-detecting code added to a frame. Another usage is padding which means adding data to reach a minimum required packet length.
+	 *
+	 * Although this layer inherits from the Layer class, it is not a standard layer in the sense that it can't be constructed by the user.
+	 * This layer may be only be constructed in the Packet class, in the process of parsing the packet and creating the layers; if at the end
+	 * of the parsing process there is data left that is not allocated to any layer, it's assumed to be the packet trailer and an instance of
+	 * this class is created. This means this layer can only exist as the last layer in a packet, if a packet trailer indeed exists.
+	 *
+	 * No layer can be added by the user after this layer (trying to do that will result with an error).
+	 *
+	 * This layer can be removed by the user or extended/shortened, as any layer.
+	 *
+	 * It also contains method to extract the trailer data
+	 */
+	class PacketTrailerLayer : public Layer
+	{
+	public:
+		 /** A constructor that creates the layer from an existing packet raw data
+		 * @param[in] data A pointer to the raw data
+		 * @param[in] dataLen Size of the data in bytes
+		 * @param[in] prevLayer A pointer to the previous layer
+		 * @param[in] packet A pointer to the Packet instance where layer will be stored in
+		 */
+		PacketTrailerLayer(uint8_t* data, size_t dataLen, Layer* prevLayer, Packet* packet) : Layer(data, dataLen, prevLayer, packet) { m_Protocol = PacketTrailer; }
+
+		~PacketTrailerLayer() {}
+
+		/**
+		 * Get a pointer to the trailer data
+		 * @return A pointer to the trailer data
+		 */
+		uint8_t* getTrailerData() const { return m_Data; }
+
+		/**
+		 * @return Trailer data as hex string
+		 */
+		std::string getTrailerDataAsHexString() const;
+
+		/**
+		 * Get the trailer data length
+		 * @return The trailer data length in bytes
+		 */
+		size_t getTrailerLen() const { return m_DataLen; }
+
+		// implement abstract methods
+
+		/**
+		 * Does nothing for this layer (PacketTrailerLayer is always last)
+		 */
+		void parseNextLayer() {}
+
+		/**
+		 * @return trailer data length in bytes
+		 */
+		size_t getHeaderLen() const { return m_DataLen; }
+
+		/**
+		 * Does nothing for this layer
+		 */
+		void computeCalculateFields() {}
+
+		std::string toString() const;
+
+		OsiModelLayer getOsiModelLayer() const { return OsiModelDataLinkLayer; }
+	};
+
+}
+
+#endif // PACKETPP_PACKET_TRAILER_LAYER