Update README and add contrib dir

contrib/tsn/model/stream-identification-function-null.h

@@ -0,0 +1,52 @@
+#ifndef NULL_STREAM_IDENTIFICATION_FUNCTION_H
+#define NULL_STREAM_IDENTIFICATION_FUNCTION_H
+
+#include "stream-identification-function.h"
+
+#include "ns3/mac48-address.h"
+#include "ns3/packet.h"
+
+
+namespace ns3
+{
+
+class NullStreamIdentificationFunction : public StreamIdentificationFunction
+{
+  public:
+    /**
+     * \brief Get the TypeId
+     *
+     * \return The TypeId for this class
+     */
+    static TypeId GetTypeId();
+
+    /**
+     * \brief Create a NullStreamIdentificationFunction
+     */
+    NullStreamIdentificationFunction();
+
+    /**
+     * Destroy a NullStreamIdentificationFunction
+     *
+     * This is the destructor for the NullStreamIdentificationFunction.
+     */
+    ~NullStreamIdentificationFunction();
+
+    // Delete copy constructor and assignment operator to avoid misuse
+    NullStreamIdentificationFunction& operator=(const NullStreamIdentificationFunction&) = delete;
+    NullStreamIdentificationFunction(const NullStreamIdentificationFunction&) = delete;
+
+    bool Match(Ptr<Packet> p) override;
+    void GetActiveUpdate(Ptr<Packet> p) override;
+
+  protected:
+
+
+  private:
+    Address m_destAddress;
+    uint16_t m_vid;
+
+};
+
+}
+#endif /* NULL_STREAM_IDENTIFICATION_FUNCTION_H */