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Initial signer rewrite in Go

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This commit is contained in:
Jan Dittberner 2018-10-31 11:17:51 +01:00
commit a89275a8e4
9 changed files with 557 additions and 0 deletions
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28
datastructures/common.go Normal file
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package datastructures
import "encoding/binary"
type Action uint8
const ActionNul = Action(0)
func encode24BitLength(data []byte) []byte {
lengthBytes := make([]byte, 4)
binary.BigEndian.PutUint32(lengthBytes, uint32(len(data)))
return lengthBytes[1:]
}
// calculate length from 24 bits of data in network byte order
func decode24BitLength(bytes []byte) int {
return int(binary.BigEndian.Uint32([]byte{0x0, bytes[0], bytes[1], bytes[2]}))
}
func CalculateXorCheckSum(byteBlocks [][]byte) byte {
var result byte = 0x0
for _, byteBlock := range byteBlocks {
for _, b := range byteBlock {
result ^= b
}
}
return result
}

80
datastructures/signerrequest.go Normal file
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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
}
func SignerRequestFromData(lengthBytes []byte, blockData []byte, checkSum byte) (*SignerRequest, error) {
headerLength := decode24BitLength(blockData[0:3])
headerBytes := blockData[3 : 3+headerLength]
contentBytes := blockData[3+headerLength:]
content1Length := decode24BitLength(contentBytes[0:3])
content1 := string(contentBytes[3 : 3+content1Length])
content2Offset := 3 + content1Length
content2Length := decode24BitLength(contentBytes[content2Offset : content2Offset+3])
content2 := string(contentBytes[3+content2Offset : 3+content2Offset+content2Length])
content3Offset := 3 + content2Offset + content2Length
content3Length := decode24BitLength(contentBytes[content3Offset : content3Offset+3])
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: 1, Action: ActionNul, Content1: time.Now().UTC().Format("010203042006.05")}
}

63
datastructures/signerresponse.go Normal file
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package datastructures
import (
"bytes"
"errors"
"fmt"
)
type SignerResponse struct {
Version uint8
Action Action
Reserved1 uint8
Reserved2 uint8
Content1 string
Content2 string
Content3 string
}
func SignerResponseFromData(lengthBytes []byte, blockData []byte, checkSum byte) (*SignerResponse, error) {
headerLength := decode24BitLength(lengthBytes)
headerBytes := blockData[3 : 3+headerLength]
contentBytes := blockData[3+headerLength:]
content1Length := decode24BitLength(contentBytes[0:3])
content1 := string(contentBytes[3 : 3+content1Length])
content2Offset := 3 + content1Length
content2Length := decode24BitLength(contentBytes[content2Offset : content2Offset+3])
content2 := string(contentBytes[3+content2Offset : 3+content2Offset+content2Length])
content3Offset := 3 + content2Offset + content2Length
content3Length := decode24BitLength(contentBytes[content3Offset : content3Offset+3])
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 &SignerResponse{
Version: headerBytes[0],
Action: Action(headerBytes[1]),
Reserved1: headerBytes[2],
Reserved2: headerBytes[3],
Content1: content1,
Content2: content2,
Content3: content3,
}, nil
}
func (r SignerResponse) Serialize() []byte {
headerBytes := []byte{r.Version, byte(r.Action), r.Reserved1, r.Reserved2}
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{})
}