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cacert-gosigner
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Refactor signer code into command and package

This commit is contained in:
Jan Dittberner 2021-01-04 14:15:12 +01:00
parent 3a2578ae55
commit 38566f35ef
13 changed files with 476 additions and 276 deletions
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13
.editorconfig Normal file
View File

@ -0,0 +1,13 @@
root = true
[*]
charset = utf-8
end_of_line = lf
indent_size = 4
indent_style = space
insert_final_newline = false
max_line_length = 120
tab_width = 4
[{*.go,*.go2}]
indent_style = tab

4
client/main.go
View File

@ -2,7 +2,6 @@ package main
import (
"flag"
"io"
"os"
"os/signal"
"sync"
@ -45,13 +44,12 @@ func main() {
requestChannel := protocol.NewSignerProtocolRequestChannel()
responseChannel := make(chan *datastructures.SignerResponse, 1)
readWriteCloser := (io.ReadWriteCloser)(port)
clientProtocolConfig := protocol.NewSignerProtocolConfig()
if clientConfig.BufferSize != 0 {
clientProtocolConfig.BufferSize = int(clientConfig.BufferSize)
}
protocolHandler := protocol.NewProtocolHandler(
requestChannel, &responseChannel, &readWriteCloser, clientProtocolConfig,
requestChannel, &responseChannel, port, clientProtocolConfig,
)
cancelChannel := make(chan os.Signal, 1)

5
client/processing/process.go
View File

@ -2,7 +2,10 @@ package processing
import (
"fmt"
"git.cacert.org/cacert-gosigner/datastructures"
"git.cacert.org/cacert-gosigner/shared"
"github.com/sirupsen/logrus"
)
@ -11,7 +14,7 @@ func Process(response *datastructures.SignerResponse) (err error) {
logrus.Tracef("process response %+v", response)
switch response.Action {
case datastructures.ActionNul:
case shared.ActionNul:
logrus.Trace("received response for NUL request")
return
default:

31
client/protocol/protocol.go
View File

@ -3,12 +3,14 @@ package protocol
import (
"bytes"
"fmt"
"git.cacert.org/cacert-gosigner/datastructures"
"git.cacert.org/cacert-gosigner/shared"
log "github.com/sirupsen/logrus"
"io"
"sync"
"time"
log "github.com/sirupsen/logrus"
"git.cacert.org/cacert-gosigner/datastructures"
"git.cacert.org/cacert-gosigner/shared"
)
type SignerProtocolHandler interface {
@ -52,7 +54,7 @@ func (rc *SignerProtocolRequestChannel) IsClosed() bool {
type protocolHandler struct {
requestChannel *SignerProtocolRequestChannel
responseChannel *chan *datastructures.SignerResponse
serialConnection *io.ReadWriteCloser
serialConnection io.ReadWriteCloser
config *signerProtocolConfig
}
@ -76,7 +78,12 @@ func (ph *protocolHandler) Close() error {
return nil
}
func NewProtocolHandler(requests *SignerProtocolRequestChannel, response *chan *datastructures.SignerResponse, serialConnection *io.ReadWriteCloser, config *signerProtocolConfig) SignerProtocolHandler {
func NewProtocolHandler(
requests *SignerProtocolRequestChannel,
response *chan *datastructures.SignerResponse,
serialConnection io.ReadWriteCloser,
config *signerProtocolConfig,
) SignerProtocolHandler {
return &protocolHandler{
requestChannel: requests,
responseChannel: response,
@ -123,13 +130,13 @@ func (ph *protocolHandler) HandleSignerProtocol() error {
func (ph *protocolHandler) sendHandshake() (err error) {
var bytesWritten, bytesRead int
if bytesWritten, err = (*ph.serialConnection).Write([]byte{shared.HandshakeByte}); err != nil {
if bytesWritten, err = ph.serialConnection.Write([]byte{shared.HandshakeByte}); err != nil {
return
} else {
log.Tracef("wrote %d bytes of handshake info", bytesWritten)
}
data := make([]byte, 1)
if bytesRead, err = (*ph.serialConnection).Read(data); err != nil {
if bytesRead, err = ph.serialConnection.Read(data); err != nil {
return
}
log.Tracef("%d bytes read", bytesRead)
@ -142,13 +149,13 @@ func (ph *protocolHandler) sendHandshake() (err error) {
func (ph *protocolHandler) sendRequest(requestBytes *[]byte) error {
for {
if length, err := (*ph.serialConnection).Write(*requestBytes); err != nil {
if length, err := ph.serialConnection.Write(*requestBytes); err != nil {
return err
} else {
log.Tracef("wrote %d request bytes", length)
}
if length, err := (*ph.serialConnection).Write([]byte{
if length, err := ph.serialConnection.Write([]byte{
datastructures.CalculateXorCheckSum([][]byte{*requestBytes}),
}); err != nil {
return err
@ -156,7 +163,7 @@ func (ph *protocolHandler) sendRequest(requestBytes *[]byte) error {
log.Tracef("wrote %d checksum bytes", length)
}
if length, err := (*ph.serialConnection).Write([]byte(shared.MagicTrailer)); err != nil {
if length, err := ph.serialConnection.Write([]byte(shared.MagicTrailer)); err != nil {
return err
} else {
log.Tracef("wrote %d trailer bytes", length)
@ -184,7 +191,7 @@ func (ph *protocolHandler) waitForResponseHandshake() (err error) {
log.Warnf("received invalid handshake byte 0x%x", data[0])
return UnExpectedHandshakeByte{data[0]}
}
if err = shared.SendByte(ph.serialConnection, shared.AckByte); err != nil {
if err = shared.SendBytes(ph.serialConnection, []byte{shared.AckByte}); err != nil {
return
}
@ -229,7 +236,7 @@ func (ph *protocolHandler) readResponse() (*[]byte, *[]byte, byte, error) {
if calculatedChecksum != checkSum {
return nil, nil, 0, fmt.Errorf("calculated checksum mismatch 0x%x vs 0x%x", calculatedChecksum, checkSum)
}
if err := shared.SendByte(ph.serialConnection, shared.AckByte); err != nil {
if err := shared.SendBytes(ph.serialConnection, []byte{shared.AckByte}); err != nil {
return nil, nil, 0, err
}

71
cmd/signer/main.go Normal file
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@ -0,0 +1,71 @@
package main
import (
"flag"
"os"
"os/signal"
log "github.com/sirupsen/logrus"
"go.bug.st/serial"
"git.cacert.org/cacert-gosigner/signer"
)
func main() {
var (
address string
baudRate int
)
flag.StringVar(&address, "a", "/dev/ttyUSB0", "address")
flag.IntVar(&baudRate, "b", 115200, "baud rate")
flag.Parse()
log.SetFormatter(&log.TextFormatter{
DisableColors: true,
FullTimestamp: true,
})
log.SetLevel(log.TraceLevel)
serialMode := &serial.Mode{
BaudRate: baudRate,
DataBits: 8,
StopBits: serial.OneStopBit,
Parity: serial.NoParity,
}
log.Infof("connecting to %s using %+v", address, serialMode)
port, err := serial.Open(address, serialMode)
if err != nil {
log.Fatalf("could not open serial port: %v", err)
}
log.Info("connected")
defer func() {
err := port.Close()
if err != nil {
log.Fatalf("could not close port: %v", err)
}
log.Info("serial port closed")
}()
done := make(chan bool)
quit := make(chan os.Signal, 1)
signal.Notify(quit, os.Interrupt)
go func() {
<-quit
log.Info("server is shutting down...")
close(done)
}()
go func() {
signerProcess := signer.NewSignerProcess(port)
signerProcess.MainLoop()
close(quit)
}()
<-done
log.Infoln("server stopped")
}

21
datastructures/common.go
View File

@ -2,27 +2,6 @@ package datastructures
import "encoding/binary"
type Action uint8
const (
ActionNul = Action(0)
ActionSign = Action(1)
ActionRevoke = Action(2)
)
func (a Action) String() string {
switch a {
case ActionNul:
return "NUL"
case ActionSign:
return "SIGN"
case ActionRevoke:
return "REVOKE"
default:
return "unknown"
}
}
func encode24BitLength(data []byte) []byte {
lengthBytes := make([]byte, 4)
binary.BigEndian.PutUint32(lengthBytes, uint32(len(data)))

20
datastructures/signerrequest.go
View File

@ -3,14 +3,14 @@ package datastructures
import (
"bytes"
"encoding/binary"
"errors"
"fmt"
"time"
"git.cacert.org/cacert-gosigner/shared"
)
type SignerRequest struct {
Version uint8
Action Action
Action shared.Action
System uint8
Root uint8
Configuration uint8
@ -22,9 +22,7 @@ type SignerRequest struct {
Content3 string
}
const protocolVersion = 1
func SignerRequestFromData(lengthBytes []byte, blockData []byte, checkSum byte) (*SignerRequest, error) {
func SignerRequestFromData(blockData []byte) (*SignerRequest, error) {
headerLength := Decode24BitLength(blockData[0:3])
headerBytes := blockData[3 : 3+headerLength]
@ -40,13 +38,9 @@ func SignerRequestFromData(lengthBytes []byte, blockData []byte, checkSum byte)
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]),
Action: shared.Action(headerBytes[1]),
System: headerBytes[2],
Root: headerBytes[3],
Configuration: headerBytes[4],
@ -79,8 +73,8 @@ func (r SignerRequest) Serialize() []byte {
func NewNulRequest() *SignerRequest {
return &SignerRequest{
Version: protocolVersion,
Action: ActionNul,
Version: shared.ProtocolVersion,
Action: shared.ActionNul,
Content1: time.Now().UTC().Format("010203042006.05"),
}
}

6
datastructures/signerresponse.go
View File

@ -4,11 +4,13 @@ import (
"bytes"
"errors"
"fmt"
"git.cacert.org/cacert-gosigner/shared"
)
type SignerResponse struct {
Version uint8
Action Action
Action shared.Action
Reserved1 uint8
Reserved2 uint8
Content1 string
@ -45,7 +47,7 @@ func SignerResponseFromData(lengthBytes []byte, blockData []byte, checkSum byte)
return &SignerResponse{
Version: headerBytes[0],
Action: Action(headerBytes[1]),
Action: shared.Action(headerBytes[1]),
Reserved1: headerBytes[2],
Reserved2: headerBytes[3],
Content1: content[0],

37
shared/io.go
View File

@ -2,30 +2,37 @@ package shared
import (
"fmt"
log "github.com/sirupsen/logrus"
"io"
"time"
log "github.com/sirupsen/logrus"
)
// receive at maximum the requested number of bytes from serial port and stop after the given timeout
func ReceiveBytes(port *io.ReadWriteCloser, count int, timeout time.Duration) ([]byte, error) {
func ReceiveBytes(port io.Reader, count int, timeout time.Duration) ([]byte, error) {
readCh := make(chan []byte, 1)
errCh := make(chan error, 1)
go func() {
data := make([]byte, count)
if readBytes, err := (*port).Read(data); err != nil {
errCh <- err
} else if readBytes > 0 {
log.Tracef("%d bytes read", readBytes)
readCh <- data[0:readBytes]
} else {
readCh <- make([]byte, 0)
sumRead := 0
for {
data := make([]byte, count)
if readBytes, err := port.Read(data); err != nil {
errCh <- err
} else if readBytes > 0 {
log.Tracef("%d bytes read", readBytes)
sumRead += readBytes
readCh <- data[0:readBytes]
} else {
readCh <- make([]byte, 0)
}
if sumRead >= count {
break
}
}
return
}()
select {
case <-time.After(timeout):
return nil, fmt.Errorf("timeout passed %v: %v", timeout)
return nil, fmt.Errorf("timeout passed %v", timeout)
case err := <-errCh:
return nil, err
case data := <-readCh:
@ -33,11 +40,11 @@ func ReceiveBytes(port *io.ReadWriteCloser, count int, timeout time.Duration) ([
}
}
func SendByte(port *io.ReadWriteCloser, data byte) error {
if bytesWritten, err := (*port).Write([]byte{data}); err != nil {
func SendBytes(port io.Writer, data []byte) error {
if bytesWritten, err := port.Write(data); err != nil {
return err
} else {
log.Tracef("wrote %d bytes of handshake info", bytesWritten)
log.Tracef("wrote %d bytes", bytesWritten)
}
return nil
}

37
shared/shared.go
View File

@ -1,7 +1,36 @@
package shared
const MagicTrailer = "rie4Ech7"
const (
ProtocolVersion = 1
const HandshakeByte = 0x02
const AckByte = 0x10
const ResendByte = 0x11
HandshakeByte = 0x02
AckByte = 0x10
ResendByte = 0x11
MagicTrailer = "rie4Ech7"
LengthFieldSize = 3
CheckSumFieldSize = 1
TrailerFieldSize = len(MagicTrailer)
)
type Action uint8
const (
ActionNul = Action(0)
ActionSign = Action(1)
ActionRevoke = Action(2)
)
func (a Action) String() string {
switch a {
case ActionNul:
return "NUL"
case ActionSign:
return "SIGN"
case ActionRevoke:
return "REVOKE"
default:
return "unknown"
}
}

90
signer/command_processor.go Normal file
View File

@ -0,0 +1,90 @@
package signer
import (
"errors"
"fmt"
"unsafe"
log "github.com/sirupsen/logrus"
"golang.org/x/sys/unix"
"git.cacert.org/cacert-gosigner/datastructures"
"git.cacert.org/cacert-gosigner/shared"
)
// The CommandProcessor takes parsed protocol data and executes the actual
// functionality.
type CommandProcessor struct {
}
// Process the signer request
func (p *CommandProcessor) Process(command datastructures.SignerRequest) (
response *datastructures.SignerResponse,
err error,
) {
log.Infof("analyze %+v", command)
switch command.Action {
case shared.ActionNul:
response, err = p.handleNulAction(command)
return
case shared.ActionSign:
response, err = p.handleSignAction(command)
return
case shared.ActionRevoke:
response, err = p.handleRevokeAction(command)
return
default:
return nil, errors.New(fmt.Sprintf(
"unsupported Action 0x%02x %s",
int(command.Action),
command.Action,
))
}
}
func (*CommandProcessor) handleNulAction(command datastructures.SignerRequest) (
*datastructures.SignerResponse,
error,
) {
var timeSpec unix.Timespec
err := unix.ClockGettime(unix.CLOCK_REALTIME, &timeSpec)
if err != nil {
log.Errorf("could not get system time: %v", err)
}
log.Debugf("current system time is %v", timeSpec)
// TODO: calculate the actual system time from the payload
_, _, e1 := unix.Syscall(
unix.SYS_CLOCK_SETTIME,
uintptr(unix.CLOCK_REALTIME),
uintptr(unsafe.Pointer(&timeSpec)),
0,
)
if e1 != 0 {
log.Errorf("could not set system time: %v", e1)
}
return &datastructures.SignerResponse{
Version: command.Version, Action: command.Action,
Content1: "", Content2: "", Content3: ""}, nil
}
func (p *CommandProcessor) handleSignAction(
command datastructures.SignerRequest,
) (
*datastructures.SignerResponse,
error,
) {
log.Debugf("handle sign call: %v", command)
return nil, errors.New("not implemented yet")
}
func (p *CommandProcessor) handleRevokeAction(
command datastructures.SignerRequest,
) (
*datastructures.SignerResponse,
error,
) {
log.Debugf("handle revoke call: %v", command)
return nil, errors.New("not implemented yet")
}

205
signer/main.go
View File

@ -1,205 +0,0 @@
package main
import (
"errors"
"flag"
"fmt"
"io"
"time"
log "github.com/sirupsen/logrus"
"go.bug.st/serial"
"git.cacert.org/cacert-gosigner/datastructures"
"git.cacert.org/cacert-gosigner/shared"
)
var (
address string
baudrate int
)
func main() {
flag.StringVar(&address, "a", "/dev/ttyUSB0", "address")
flag.IntVar(&baudrate, "b", 115200, "baud rate")
flag.Parse()
log.SetFormatter(&log.TextFormatter{
DisableColors: true,
FullTimestamp: true,
})
serialMode := &serial.Mode{
BaudRate: baudrate,
DataBits: 8,
StopBits: serial.OneStopBit,
Parity: serial.NoParity,
}
log.Infof("connecting to %s using %+v", address, serialMode)
port, err := serial.Open(address, serialMode)
if err != nil {
log.Fatalf("could not open serial port: %v", err)
}
log.Info("connected")
count := 0
defer func() {
err := port.Close()
if err != nil {
log.Fatalf("could not close port: %v", err)
}
log.Info("closed")
}()
readLoop:
for {
// timeout if no command has been received within 15 seconds
timeout := time.After(15 * time.Second)
commandChan := make(chan datastructures.SignerRequest, 1)
errChan := make(chan error, 1)
readWriteCloser := (io.ReadWriteCloser)(port)
go Receive(&readWriteCloser, &commandChan, &errChan)
select {
case command := <-commandChan:
response, err := Process(command)
if err != nil {
log.Errorf("error processing command: %v", err)
break readLoop
}
_ = SendResponse(&readWriteCloser, response)
case <-timeout:
log.Error("timeout in main loop")
break readLoop
case err := <-errChan:
log.Errorf("error from io goroutine %v", err)
}
count++
log.Infof("%d requests processed. Waiting for next request ...", count)
}
}
// Send a response to the client
func SendResponse(port *io.ReadWriteCloser, response *datastructures.SignerResponse) error {
if _, err := (*port).Write([]byte{0x02}); err != nil {
return err
}
if ack, err := shared.ReceiveBytes(port, 1, 5*time.Second); err != nil {
return err
} else if ack[0] != 0x10 {
return errors.New(fmt.Sprintf("invalid ack byte 0x%02x", ack[0]))
}
tryAgain := true
for tryAgain {
data := response.Serialize()
if _, err := (*port).Write(data); err != nil {
return err
}
checksum := datastructures.CalculateXorCheckSum([][]byte{data})
if _, err := (*port).Write([]byte{checksum}); err != nil {
return err
}
if _, err := (*port).Write([]byte(shared.MagicTrailer)); err != nil {
return err
}
if ack, err := shared.ReceiveBytes(port, 1, 5*time.Second); err != nil {
return err
} else if ack[0] == 0x10 {
tryAgain = false
} else if ack[0] != 0x11 {
return errors.New(fmt.Sprintf("invalid ack byte 0x%02x", ack[0]))
}
}
return nil
}
// Process the signer request
func Process(command datastructures.SignerRequest) (response *datastructures.SignerResponse, err error) {
log.Infof("analyze %+v", command)
switch command.Action {
case datastructures.ActionNul:
response, err = handleNulAction(command)
return
default:
return nil, errors.New(fmt.Sprintf(
"unsupported Action 0x%02x %s",
int(command.Action),
command.Action,
))
}
}
func handleNulAction(command datastructures.SignerRequest) (*datastructures.SignerResponse, error) {
// todo: generate script to set system time from command time data in command.content1
return &datastructures.SignerResponse{
Version: command.Version, Action: command.Action,
Content1: "", Content2: "", Content3: ""}, nil
}
// Receive a request and generate a request data structure
func Receive(port *io.ReadWriteCloser, commandChan *chan datastructures.SignerRequest, errorChan *chan error) {
header, err := shared.ReceiveBytes(port, 1, 20*time.Second)
if err != nil {
*errorChan <- err
return
}
if header[0] != shared.HandshakeByte {
*errorChan <- fmt.Errorf("unexpected byte 0x%x expected 0x%x", header[0], shared.HandshakeByte)
}
if _, err := (*port).Write([]byte{shared.AckByte}); err != nil {
*errorChan <- errors.New("could not write ACK")
return
}
lengthBytes, err := shared.ReceiveBytes(port, 3, 2*time.Second)
if err != nil {
*errorChan <- err
return
}
blockLength := datastructures.Decode24BitLength(lengthBytes)
blockData, err := shared.ReceiveBytes(port, blockLength, 5*time.Second)
if err != nil {
*errorChan <- err
return
}
checkSum, err := shared.ReceiveBytes(port, 1, 2*time.Second)
if err != nil {
*errorChan <- err
return
}
command, err := datastructures.SignerRequestFromData(lengthBytes, blockData, checkSum[0])
if err != nil {
*errorChan <- err
return
}
trailer, err := shared.ReceiveBytes(port, len(shared.MagicTrailer), 2*time.Second)
if err != nil {
*errorChan <- err
return
}
if string(trailer) != shared.MagicTrailer {
*errorChan <- errors.New("expected trailer bytes not found")
return
}
if _, err := (*port).Write([]byte{0x10}); err != nil {
*errorChan <- err
return
}
*commandChan <- *command
}

212
signer/port_handler.go Normal file
View File

@ -0,0 +1,212 @@
package signer
import (
"errors"
"fmt"
"io"
"time"
log "github.com/sirupsen/logrus"
"git.cacert.org/cacert-gosigner/datastructures"
"git.cacert.org/cacert-gosigner/shared"
)
const (
waitForHandShake = time.Second * 5
waitForInitialByte = time.Second * 20
waitForLengthBytes = time.Second * 2
waitForChecksumByte = time.Second * 2
waitForTrailerBytes = time.Second * 2
waitForBlock = time.Minute * 1
maxTriesPerBlock = 10_000
)
// The PortHandler takes care of reading and writing of raw bytes from/to a serial port
type PortHandler struct {
port io.ReadWriteCloser
processor *CommandProcessor
errors chan error
commandChan chan *datastructures.SignerRequest
}
func (p *PortHandler) MainLoop() {
count := 0
for {
go p.Receive()
select {
case command := <-p.commandChan:
if command == nil {
log.Infof("command channel has been closed. stopping execution.")
return
}
log.Debugf("received command %v", command)
response, err := p.processor.Process(*command)
if err != nil {
log.Errorf("error processing command: %v", err)
close(p.commandChan)
} else {
_ = p.SendResponse(response)
}
case err := <-p.errors:
log.Errorf("error from io goroutine %v", err)
}
count++
log.Infof("%d requests processed. Waiting for next request ...", count)
}
}
// Receive a request and generate a request data structure
func (p *PortHandler) Receive() {
header, err := shared.ReceiveBytes(p.port, 1, waitForInitialByte)
if err != nil {
p.errors <- err
return
}
if header[0] != shared.HandshakeByte {
p.errors <- fmt.Errorf(
"unexpected byte 0x%x expected 0x%x",
header[0],
shared.HandshakeByte,
)
return
}
tries := maxTriesPerBlock
var command *datastructures.SignerRequest
for {
if tries <= 0 {
p.errors <- errors.New("tried reading block too often")
break
}
tries--
if err := shared.SendBytes(p.port, []byte{shared.AckByte}); err != nil {
p.errors <- fmt.Errorf("could not write ACK byte: %v", err)
break
}
lengthBytes, err := shared.ReceiveBytes(p.port, shared.LengthFieldSize, waitForLengthBytes)
if err != nil {
p.errors <- fmt.Errorf("could not read lenght bytes: %v", err)
break
}
blockLength := datastructures.Decode24BitLength(lengthBytes)
blockData, err := shared.ReceiveBytes(p.port, blockLength, waitForBlock)
if err != nil {
p.errors <- fmt.Errorf("could not read data block: %v", err)
if !p.requestResend() {
break
}
continue
}
checkSum, err := shared.ReceiveBytes(p.port, shared.CheckSumFieldSize, waitForChecksumByte)
if err != nil {
p.errors <- fmt.Errorf("could not read checksum byte: %v", err)
break
}
calculated := datastructures.CalculateXorCheckSum([][]byte{lengthBytes, blockData})
if checkSum[0] != calculated {
p.errors <- fmt.Errorf("CRC error. expected 0x%02x, got 0x%02x", calculated, checkSum[0])
if !p.requestResend() {
break
}
continue
}
trailer, err := shared.ReceiveBytes(p.port, shared.TrailerFieldSize, waitForTrailerBytes)
if err != nil {
p.errors <- fmt.Errorf("could not read trailer bytes: %v", err)
break
}
if string(trailer) != shared.MagicTrailer {
p.errors <- fmt.Errorf(
"BROKEN block detected, expected trailer bytes '%s' not found, got '%s' instead",
shared.MagicTrailer,
trailer,
)
if !p.requestResend() {
break
}
continue
}
command, err = datastructures.SignerRequestFromData(blockData)
if err != nil {
p.errors <- fmt.Errorf("failed to parse block as signer request: %v", err)
break
}
if err := shared.SendBytes(p.port, []byte{shared.AckByte}); err != nil {
p.errors <- fmt.Errorf("failed to send ACK byte: %v", err)
break
}
p.commandChan <- command
break
}
}
func (p *PortHandler) requestResend() bool {
if err := shared.SendBytes(p.port, []byte{shared.ResendByte}); err != nil {
p.errors <- err
return false
}
return true
}
// Send a response to the client
func (p *PortHandler) SendResponse(response *datastructures.SignerResponse) error {
if err := shared.SendBytes(p.port, []byte{shared.HandshakeByte}); err != nil {
return err
}
if ack, err := shared.ReceiveBytes(p.port, 1, waitForHandShake); err != nil {
return err
} else if ack[0] != shared.AckByte {
return errors.New(fmt.Sprintf("invalid ack byte 0x%02x", ack[0]))
}
tryAgain := true
for tryAgain {
data := response.Serialize()
if err := shared.SendBytes(p.port, data); err != nil {
return err
}
checksum := datastructures.CalculateXorCheckSum([][]byte{data})
if err := shared.SendBytes(p.port, []byte{checksum}); err != nil {
return err
}
if err := shared.SendBytes(p.port, []byte(shared.MagicTrailer)); err != nil {
return err
}
if ack, err := shared.ReceiveBytes(p.port, 1, waitForHandShake); err != nil {
return err
} else if ack[0] == shared.AckByte {
tryAgain = false
} else if ack[0] != 0x11 {
return errors.New(fmt.Sprintf("invalid ack byte 0x%02x", ack[0]))
}
}
return nil
}
func NewSignerProcess(port io.ReadWriteCloser) *PortHandler {
errorChan := make(chan error)
return &PortHandler{
port: port,
errors: errorChan,
commandChan: make(chan *datastructures.SignerRequest, 1),
processor: &CommandProcessor{},
}
}