Communication: Create EthernetPacketizer

This code previously was separately maintained in each of the
PCAP driver layers.

While adding complexity for reassembly, I decided it was
time to pull it out into a common implementation.

As of this commit, the old implementations have not been
removed from the PCAP drivers yet.

include/icsneo/communication/ethernetpacketizer.h

@@ -0,0 +1,80 @@
+#ifndef __ETHERNETPACKETIZER_H_
+#define __ETHERNETPACKETIZER_H_
+
+#ifdef __cplusplus
+
+#include "icsneo/api/eventmanager.h"
+#include <queue>
+#include <vector>
+#include <memory>
+
+namespace icsneo {
+
+/**
+ * A layer of encapsulation on top of the standard packetizer
+ * for 0xCAB1/0xCAB2 Ethernet packets.
+ * 
+ * Not thread-safe by default.
+ */
+class EthernetPacketizer {
+public:
+	EthernetPacketizer(device_eventhandler_t report) : report(report) {}
+
+	/**
+	 * Call with as many packets as desired before calling
+	 * outputDown to get the results. Passing in multiple
+	 * packets may result in better packing.
+	 */
+	void inputDown(std::vector<uint8_t> bytes);
+	std::vector< std::vector<uint8_t> > outputDown();
+
+	/**
+	 * Call with packet data, the packet may be queued waiting
+	 * for reassembly. In this case, false will be returned.
+	 */
+	bool inputUp(std::vector<uint8_t> bytes);
+	std::vector<uint8_t> outputUp();
+
+	class EthernetPacket {
+	public: // Don't worry about endian when setting fields, this is all taken care of in getBytestream
+		EthernetPacket() {};
+		EthernetPacket(const std::vector<uint8_t>& bytestream);
+		EthernetPacket(const uint8_t* data, size_t size);
+		int loadBytestream(const std::vector<uint8_t>& bytestream);
+		std::vector<uint8_t> getBytestream() const;
+		uint8_t errorWhileDecodingFromBytestream = 0; // Not part of final bytestream, only for checking the result of the constructor
+		uint8_t destMAC[6] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
+		uint8_t srcMAC[6] = { 0x00, 0xFC, 0x70, 0xFF, 0xFF, 0xFF };
+		uint16_t etherType = 0xCAB1; // Big endian, Should be 0xCAB1 or 0xCAB2
+		uint32_t icsEthernetHeader = 0xAAAA5555; // Big endian, Should be 0xAAAA5555
+		// At this point in the packet, there is a 16-bit payload size, little endian
+		// This is calculated from payload size in getBytestream
+		uint16_t packetNumber = 0;
+		bool firstPiece = true; // These booleans make up a 16-bit bitfield, packetInfo
+		bool lastPiece = true;
+		bool bufferHalfFull = false;
+		std::vector<uint8_t> payload;
+	};
+
+	uint8_t hostMAC[6] = { 0x00, 0xFC, 0x70, 0xFF, 0xFF, 0xFF };
+	uint8_t deviceMAC[6] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
+	
+private:
+	bool reassembling = false;
+	uint16_t reassemblingId = 0;
+	std::vector<uint8_t> reassemblingData;
+	uint16_t sequenceDown = 0;
+	uint16_t sequenceUp = 0;
+	bool gotUp = false; // Mark whether sequenceUp is actually valid
+
+	std::vector<uint8_t> processedUpBytes;
+	std::vector< std::vector<uint8_t> > processedDownPackets;
+
+	device_eventhandler_t report;
+};
+
+}
+
+#endif // __cplusplus
+
+#endif