/
protocol.go
170 lines (157 loc) · 3.49 KB
/
protocol.go
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package socks4
import (
"bytes"
"encoding/binary"
"io"
"net/netip"
"os"
E "github.com/MehranF123/sing/common/exceptions"
M "github.com/MehranF123/sing/common/metadata"
"github.com/MehranF123/sing/common/rw"
)
const (
Version byte = 4
CommandConnect byte = 1
CommandBind byte = 2
ReplyCodeGranted byte = 90
ReplyCodeRejectedOrFailed byte = 91
ReplyCodeCannotConnectToIdentd byte = 92
ReplyCodeIdentdReportDifferentUserID byte = 93
)
type Request struct {
Command byte
Destination M.Socksaddr
Username string
}
func ReadRequest(reader io.Reader) (request Request, err error) {
version, err := rw.ReadByte(reader)
if err != nil {
return
}
if version != 4 {
err = E.New("excepted socks version 4, got ", version)
return
}
return ReadRequest0(reader)
}
func ReadRequest0(reader io.Reader) (request Request, err error) {
request.Command, err = rw.ReadByte(reader)
if err != nil {
return
}
err = binary.Read(reader, binary.BigEndian, &request.Destination.Port)
if err != nil {
return
}
var dstIP [4]byte
_, err = io.ReadFull(reader, dstIP[:])
if err != nil {
return
}
var readHostName bool
if dstIP[0] == 0 && dstIP[1] == 0 && dstIP[2] == 0 {
readHostName = true
} else {
request.Destination.Addr = netip.AddrFrom4(dstIP)
}
request.Username, err = readString(reader)
if readHostName {
request.Destination.Fqdn, err = readString(reader)
}
return
}
func WriteRequest(writer io.Writer, request Request) error {
if request.Command != CommandConnect && request.Command != CommandBind {
return os.ErrInvalid
}
_, err := writer.Write([]byte{Version, request.Command})
if err != nil {
return err
}
err = binary.Write(writer, binary.BigEndian, request.Destination.Port)
if err != nil {
return err
}
if request.Destination.IsIPv4() {
dstIP := request.Destination.Addr.As4()
_, err = writer.Write(dstIP[:])
if err != nil {
return err
}
} else {
err = rw.WriteZeroN(writer, 4)
if err != nil {
return err
}
_, err = writer.Write([]byte(request.Destination.AddrString()))
if err != nil {
return err
}
err = rw.WriteZero(writer)
if err != nil {
return err
}
}
if request.Username != "" {
_, err = writer.Write([]byte(request.Username))
if err != nil {
return err
}
}
return rw.WriteZero(writer)
}
type Response struct {
ReplyCode byte
Destination M.Socksaddr
}
func ReadResponse(reader io.Reader) (response Response, err error) {
version, err := rw.ReadByte(reader)
if err != nil {
return
}
if version != 0 {
err = E.New("excepted socks4 response version 0, got ", version)
return
}
response.ReplyCode, err = rw.ReadByte(reader)
if err != nil {
return
}
err = binary.Read(reader, binary.BigEndian, &response.Destination.Port)
if err != nil {
return
}
var dstIP [4]byte
_, err = io.ReadFull(reader, dstIP[:])
if err != nil {
return
}
response.Destination.Addr = netip.AddrFrom4(dstIP)
return
}
func WriteResponse(writer io.Writer, response Response) error {
_, err := writer.Write([]byte{0, response.ReplyCode})
if err != nil {
return err
}
err = binary.Write(writer, binary.BigEndian, response.Destination.Port)
if err != nil {
return err
}
dstIP := response.Destination.Addr.As4()
return rw.WriteBytes(writer, dstIP[:])
}
func readString(reader io.Reader) (string, error) {
buffer := bytes.Buffer{}
for {
b, err := rw.ReadByte(reader)
if err != nil {
return "", err
}
if b == 0 {
break
}
buffer.WriteByte(b)
}
return buffer.String(), nil
}