IP now fills automatically the sender address when no link layer PDU is present. Made some protocols work when using PacketSender::send_recv.

include/tcp.h

@@ -392,6 +392,15 @@ namespace Tins {
          * \sa PDU::header_size
          */
         uint32_t header_size() const;
+        
+        /**
+         * \brief Check wether ptr points to a valid response for this PDU.
+         *
+         * \sa PDU::matches_response
+         * \param ptr The pointer to the buffer.
+         * \param total_sz The size of the buffer.
+         */
+        bool matches_response(uint8_t *ptr, uint32_t total_sz);
 
         /**
          * \brief Getter for the PDU's type.