github.com/aigarnetwork/aigar@v0.0.0-20191115204914-d59a6eb70f8e/accounts/scwallet/apdu.go (about)

     1  //  Copyright 2018 The go-ethereum Authors
     2  //  Copyright 2019 The go-aigar Authors
     3  //  This file is part of the go-aigar library.
     4  //
     5  //  The go-aigar library is free software: you can redistribute it and/or modify
     6  //  it under the terms of the GNU Lesser General Public License as published by
     7  //  the Free Software Foundation, either version 3 of the License, or
     8  //  (at your option) any later version.
     9  //
    10  //  The go-aigar library is distributed in the hope that it will be useful,
    11  //  but WITHOUT ANY WARRANTY; without even the implied warranty of
    12  //  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    13  //  GNU Lesser General Public License for more details.
    14  //
    15  //  You should have received a copy of the GNU Lesser General Public License
    16  //  along with the go-aigar library. If not, see <http://www.gnu.org/licenses/>.
    17  
    18  package scwallet
    19  
    20  import (
    21  	"bytes"
    22  	"encoding/binary"
    23  	"fmt"
    24  )
    25  
    26  // commandAPDU represents an application data unit sent to a smartcard.
    27  type commandAPDU struct {
    28  	Cla, Ins, P1, P2 uint8  // Class, Instruction, Parameter 1, Parameter 2
    29  	Data             []byte // Command data
    30  	Le               uint8  // Command data length
    31  }
    32  
    33  // serialize serializes a command APDU.
    34  func (ca commandAPDU) serialize() ([]byte, error) {
    35  	buf := new(bytes.Buffer)
    36  
    37  	if err := binary.Write(buf, binary.BigEndian, ca.Cla); err != nil {
    38  		return nil, err
    39  	}
    40  	if err := binary.Write(buf, binary.BigEndian, ca.Ins); err != nil {
    41  		return nil, err
    42  	}
    43  	if err := binary.Write(buf, binary.BigEndian, ca.P1); err != nil {
    44  		return nil, err
    45  	}
    46  	if err := binary.Write(buf, binary.BigEndian, ca.P2); err != nil {
    47  		return nil, err
    48  	}
    49  	if len(ca.Data) > 0 {
    50  		if err := binary.Write(buf, binary.BigEndian, uint8(len(ca.Data))); err != nil {
    51  			return nil, err
    52  		}
    53  		if err := binary.Write(buf, binary.BigEndian, ca.Data); err != nil {
    54  			return nil, err
    55  		}
    56  	}
    57  	if err := binary.Write(buf, binary.BigEndian, ca.Le); err != nil {
    58  		return nil, err
    59  	}
    60  	return buf.Bytes(), nil
    61  }
    62  
    63  // responseAPDU represents an application data unit received from a smart card.
    64  type responseAPDU struct {
    65  	Data     []byte // response data
    66  	Sw1, Sw2 uint8  // status words 1 and 2
    67  }
    68  
    69  // deserialize deserializes a response APDU.
    70  func (ra *responseAPDU) deserialize(data []byte) error {
    71  	if len(data) < 2 {
    72  		return fmt.Errorf("can not deserialize data: payload too short (%d < 2)", len(data))
    73  	}
    74  
    75  	ra.Data = make([]byte, len(data)-2)
    76  
    77  	buf := bytes.NewReader(data)
    78  	if err := binary.Read(buf, binary.BigEndian, &ra.Data); err != nil {
    79  		return err
    80  	}
    81  	if err := binary.Read(buf, binary.BigEndian, &ra.Sw1); err != nil {
    82  		return err
    83  	}
    84  	if err := binary.Read(buf, binary.BigEndian, &ra.Sw2); err != nil {
    85  		return err
    86  	}
    87  	return nil
    88  }