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

include/bootp.h

@@ -293,6 +293,17 @@ namespace Tins {
          */
         void vend(const vend_type &new_vend);
 
+        /**
+         * \brief Check wether ptr points to a valid response for this PDU.
+         *
+         * This returns true, if the xid field is equal.
+         * 
+         * \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.
          * \sa PDU::pdu_type