cacert-gosigner/datastructures/signerrequest.go

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package datastructures
import (
"bytes"
"encoding/binary"
"errors"
"fmt"
"time"
)
type SignerRequest struct {
Version uint8
Action Action
System uint8
Root uint8
Configuration uint8
Parameter1 uint8
Parameter2 uint16
Parameter3 uint8
Content1 string
Content2 string
Content3 string
}
const protocolVersion = 1
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func SignerRequestFromData(lengthBytes []byte, blockData []byte, checkSum byte) (*SignerRequest, error) {
headerLength := Decode24BitLength(blockData[0:3])
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headerBytes := blockData[3 : 3+headerLength]
contentBytes := blockData[3+headerLength:]
content1Length := Decode24BitLength(contentBytes[0:3])
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content1 := string(contentBytes[3 : 3+content1Length])
content2Offset := 3 + content1Length
content2Length := Decode24BitLength(contentBytes[content2Offset : content2Offset+3])
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content2 := string(contentBytes[3+content2Offset : 3+content2Offset+content2Length])
content3Offset := 3 + content2Offset + content2Length
content3Length := Decode24BitLength(contentBytes[content3Offset : content3Offset+3])
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content3 := string(contentBytes[3+content3Offset : 3+content3Offset+content3Length])
calculated := CalculateXorCheckSum([][]byte{lengthBytes, blockData})
if checkSum != calculated {
return nil, errors.New(fmt.Sprintf("invalid checksum expected 0x%x got 0x%x", calculated, checkSum))
}
return &SignerRequest{
Version: headerBytes[0],
Action: Action(headerBytes[1]),
System: headerBytes[2],
Root: headerBytes[3],
Configuration: headerBytes[4],
Parameter1: headerBytes[5],
Parameter2: binary.BigEndian.Uint16([]byte{headerBytes[6], headerBytes[7]}),
Parameter3: headerBytes[8],
Content1: content1,
Content2: content2,
Content3: content3,
}, nil
}
func (r SignerRequest) Serialize() []byte {
parameter2Bytes := make([]byte, 2)
binary.BigEndian.PutUint16(parameter2Bytes, r.Parameter2)
headerBytes := bytes.Join([][]byte{
{r.Version, byte(r.Action), r.System, r.Root, r.Configuration, r.Parameter1},
parameter2Bytes, {r.Parameter3}}, []byte{})
content1Bytes := []byte(r.Content1)
content2Bytes := []byte(r.Content2)
content3Bytes := []byte(r.Content3)
blockBytes := bytes.Join([][]byte{
encode24BitLength(headerBytes), headerBytes,
encode24BitLength(content1Bytes), content1Bytes,
encode24BitLength(content2Bytes), content2Bytes,
encode24BitLength(content3Bytes), content3Bytes,
}, []byte{})
return bytes.Join([][]byte{encode24BitLength(blockBytes), blockBytes}, []byte{})
}
func NewNulRequest() *SignerRequest {
return &SignerRequest{
Version: protocolVersion,
Action: ActionNul,
Content1: time.Now().UTC().Format("010203042006.05"),
}
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}