A hardware protocol stack to which a user-defined protocol is applied, comprising: a register unit in which header information, of the user-defined protocol, is stored; a comparison unit configured to compare header information of a received frame with the header information stored in the register unit to determine whether the header information is matched to the other, the received frame being configured with the header information, data, and a frame check sequence, FCS; an interface logic unit configured to determine an action to be executed on the received frame on the basis of a comparison result of the comparison unit; and a logic process unit configured to process the data of the received frame based on a logic according to the header information in the register unit when the action to be executed on the received frame, which is determined in the interface logic unit according to the header information stored in the register unit and being matched to the header information of the received frame, is determined to be a processing of a frame, characterized in, that the logic according to the header information includes a unit designation of the data according to the header information, that if a unit is not designated in the data included in the received frame, the logic process unit is configured to designate a unit in the data according to the header information of the received frame, and that when the processing of the frame is a request to write payload data of the data of the frame in a specific destination region, the logic process unit is configured to set a basic offset and a size unit of the data and to store the payload data with the set basic offset by expanding the payload data to correspond to the set size unit. a register unit in which header information, of the user-defined protocol, is stored; a comparison unit configured to compare header information of a received frame with the header information stored in the register unit to determine whether the header information is matched to the other, the received frame being configured with the header information, data, and a frame check sequence, FCS; an interface logic unit configured to determine an action to be executed on the received frame on the basis of a comparison result of the comparison unit; and a logic process unit configured to process the data of the received frame based on a logic according to the header information in the register unit when the action to be executed on the received frame, which is determined in the interface logic unit according to the header information stored in the register unit and being matched to the header information of the received frame, is determined to be a processing of a frame, characterized in, that the logic according to the header information includes a unit designation of the data according to the header information, that if a unit is not designated in the data included in the received frame, the logic process unit is configured to designate a unit in the data according to the header information of the received frame, and that when the processing of the frame is a request to write payload data of the data of the frame in a specific destination region, the logic process unit is configured to set a basic offset and a size unit of the data and to store the payload data with the set basic offset by expanding the payload data to correspond to the set size unit.