Add S7COMM protocol (#1185)

Packet++/CMakeLists.txt

@@ -37,6 +37,7 @@ add_library(
   src/PPPoELayer.cpp
   src/RadiusLayer.cpp
   src/RawPacket.cpp
+  src/S7CommLayer.cpp
   src/SdpLayer.cpp
   src/SingleCommandTextProtocol.cpp
   src/SipLayer.cpp
@@ -103,6 +104,7 @@ set(public_headers
     header/ProtocolType.h
     header/RadiusLayer.h
     header/RawPacket.h
+    header/S7CommLayer.h
     header/SdpLayer.h
     header/SingleCommandTextProtocol.h
     header/SipLayer.h

Packet++/header/CotpLayer.h

@@ -95,7 +95,7 @@ namespace pcpp
 		void computeCalculateFields() override {}
 
 		/**
-		 * Currently parses the rest of the packet as a generic payload (PayloadLayer)
+		 * Currently parses the rest of the packet as a S7COMM or generic payload (PayloadLayer)
 		 */
 		void parseNextLayer() override;
 

Packet++/header/ProtocolType.h

@@ -327,6 +327,11 @@ namespace pcpp
 	 */
 	const ProtocolType SLL2 = 0x8000000000000;
 
+	/**
+	 * S7COMM protocol
+	 */
+	const ProtocolType S7COMM = 0x10000000000000;
+
 	/**
 	 * An enum representing OSI model layers
 	 */

Packet++/header/S7CommLayer.h

@@ -0,0 +1,220 @@
+#ifndef PACKETPP_S7COMM_LAYER
+#define PACKETPP_S7COMM_LAYER
+
+#include "EthLayer.h"
+#include "Layer.h"
+
+namespace pcpp
+{
+/**
+ * @struct s7commhdr
+ * Represents a S7COMM protocol header
+ */
+#pragma pack(push, 1)
+	typedef struct
+	{
+		/** protocol id */
+		uint8_t protocolId;
+		/** message type */
+		uint8_t msgType;
+		/** redundancy identification (reserved) */
+		uint16_t reserved;
+		/** protocol data unit reference */
+		uint16_t pduRef;
+		/** parameter length */
+		uint16_t paramLength;
+		/** data length */
+		uint16_t dataLength;
+	} s7commhdr;
+#pragma pack(pop)
+
+/**
+ * @struct s7comm_ack_data_hdr
+ * Represents a S7COMM protocol header with Ack-Data header
+ */
+#pragma pack(push, 1)
+	struct s7comm_ack_data_hdr : s7commhdr
+	{
+		/** error class */
+		uint8_t errorClass;
+		/** error code */
+		uint8_t errorCode;
+	};
+#pragma pack(pop)
+
+	/**
+	 * @class S7CommParameter
+	 * Represents a S7COMM (S7 Communication) protocol Parameter
+	 */
+	class S7CommParameter
+	{
+		friend class S7CommLayer;
+
+	  public:
+		S7CommParameter() {}
+
+		virtual ~S7CommParameter() {}
+
+		/**
+		 * @return The data of the Parameter
+		 */
+		uint8_t *getData() const { return m_Data; }
+		/**
+		 * @return The length of the Parameter data
+		 */
+		size_t getDataLength() const { return m_DataLen; }
+
+	  private:
+		S7CommParameter(uint8_t *data, size_t dataLen) : m_Data(data), m_DataLen(dataLen) {}
+		uint8_t *m_Data;
+		size_t m_DataLen;
+	};
+	/**
+	 * @class S7CommLayer
+	 * Represents a S7COMM (S7 Communication) protocol
+	 */
+	class S7CommLayer : public Layer
+	{
+	public:
+		/**
+		 * A constructor that allocates a new S7comm header
+		 * @param[in] msgType The general type of the message
+		 * @param[in] pduRef Link responses to their requests
+		 * @param[in] paramLength The length of the parameter field
+		 * @param[in] dataLength The length of the data field
+		 * @param[in] errorClass The value of the error class
+		 * @param[in] errorCode The value of the error code
+		 */
+		S7CommLayer(uint8_t msgType, uint16_t pduRef, uint16_t paramLength, uint16_t dataLength, uint8_t errorClass = 0,
+					uint8_t errorCode = 0);
+
+		/**
+		 * A constructor that creates the layer from an existing packet raw data
+		 * @param[in] data A pointer to the raw data (will be casted to @ref s7commhdr)
+		 * @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
+		 */
+		S7CommLayer(uint8_t *data, size_t dataLen, Layer *prevLayer, Packet *packet)
+			: Layer(data, dataLen, prevLayer, packet)
+		{
+			m_Protocol = S7COMM;
+			m_Parameter = nullptr;
+		}
+
+		virtual ~S7CommLayer()
+		{
+			if (m_Parameter)
+				delete m_Parameter;
+		}
+
+		/**
+		 * @return S7comm protocol id
+		 */
+		uint8_t getProtocolId() const;
+
+		/**
+		 * @return S7comm message type
+		 */
+		uint8_t getMsgType() const;
+
+		/**
+		 * @return S7comm PDU ref
+		 */
+		uint16_t getPduRef() const;
+
+		/**
+		 * @return S7comm parameter length
+		 */
+		uint16_t getParamLength() const;
+
+		/**
+		 * @return S7comm data length
+		 */
+		uint16_t getDataLength() const;
+
+		/**
+		 * @return S7comm error code
+		 */
+		uint8_t getErrorCode() const;
+
+		/**
+		 * @return S7comm error class
+		 */
+		uint8_t getErrorClass() const;
+
+		/**
+		 * @return S7comm parameter
+		 */
+		const S7CommParameter *getParameter();
+
+		/**
+		 * Set the value of the message type
+		 * @param[in] msgType The value of the message type
+		 */
+		void setMsgType(uint8_t msgType) const;
+
+		/**
+		 * Set the value of the PDU ref
+		 * @param[in] pduRef The value of the PDU ref
+		 */
+		void setPduRef(uint16_t pduRef) const;
+
+		/**
+		 * Set the value of the error code
+		 * @param[in] errorCode The value of the error code
+		 */
+		void setErrorCode(uint8_t errorCode) const;
+		/**
+		 * Set the value of the error class
+		 * @param[in] errorClass The value of the error class
+		 */
+		void setErrorClass(uint8_t errorClass) const;
+
+		/**
+		 * @return Size of S7CommLayer
+		 */
+		size_t getHeaderLen() const override { return m_DataLen; }
+
+		/**
+		 * Does nothing for this layer (S7CommLayer is always last)
+		 */
+		void computeCalculateFields() override {}
+
+		/**
+		 * Does nothing for this layer (S7CommLayer is always last)
+		 */
+		void parseNextLayer() override {}
+
+		/**
+		 * A static method that takes a byte array and detects whether it is a S7COMM
+		 * @param[in] data A byte array
+		 * @param[in] dataSize The byte array size (in bytes)
+		 * @return True if the data looks like a valid S7COMM layer
+		 */
+		static bool isDataValid(const uint8_t *data, size_t dataSize);
+
+		std::string toString() const override;
+
+		OsiModelLayer getOsiModelLayer() const override { return OsiModelApplicationLayer; }
+
+	private:
+		s7commhdr *getS7commHeader() const { return (s7commhdr *)m_Data; }
+
+		s7comm_ack_data_hdr *getS7commAckDataHeader() const
+		{
+			if (getS7commHeader()->msgType == 0x03)
+			{
+				return (s7comm_ack_data_hdr *)m_Data;
+			}
+			return nullptr;
+		}
+
+		size_t getS7commHeaderLength() const;
+
+		S7CommParameter *m_Parameter;
+	};
+
+} // namespace pcpp
+
+#endif // PACKETPP_S7COMM_LAYER

Packet++/src/CotpLayer.cpp

@@ -1,5 +1,6 @@
 #include "../header/CotpLayer.h"
 #include "EndianPortable.h"
+#include "S7CommLayer.h"
 #include <PayloadLayer.h>
 #include <cstring>
 #include <iostream>
@@ -21,10 +22,7 @@ namespace pcpp
 		m_Protocol = COTP;
 	}
 
-	std::string CotpLayer::toString() const
-	{
-		return "Cotp Layer";
-	}
+	std::string CotpLayer::toString() const { return "Cotp Layer"; }
 
 	uint8_t CotpLayer::getLength() const { return getCotpHeader()->length; }
 
@@ -43,7 +41,7 @@ namespace pcpp
 		if (!data || dataSize < sizeof(cotphdr))
 			return false;
 
-		return  data[1] == 0xf0 && data[0] == 2;
+		return data[1] == 0xf0 && data[0] == 2;
 	}
 
 	void CotpLayer::parseNextLayer()
@@ -55,6 +53,9 @@ namespace pcpp
 		uint8_t *payload = m_Data + headerLen;
 		size_t payloadLen = m_DataLen - headerLen;
 
-		m_NextLayer = new PayloadLayer(payload, payloadLen, this, m_Packet);
+		if (S7CommLayer::isDataValid(payload, payloadLen))
+			m_NextLayer = new S7CommLayer(payload, payloadLen, this, m_Packet);
+		else
+			m_NextLayer = new PayloadLayer(payload, payloadLen, this, m_Packet);
 	}
 } // namespace pcpp