sing-box/transport/trojan/protocol.go

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package trojan
import (
"crypto/sha256"
"encoding/binary"
"encoding/hex"
"net"
"os"
"github.com/sagernet/sing/common"
"github.com/sagernet/sing/common/buf"
"github.com/sagernet/sing/common/bufio"
E "github.com/sagernet/sing/common/exceptions"
M "github.com/sagernet/sing/common/metadata"
N "github.com/sagernet/sing/common/network"
"github.com/sagernet/sing/common/rw"
)
const (
KeyLength = 56
CommandTCP = 1
CommandUDP = 3
CommandMux = 0x7f
)
var CRLF = []byte{'\r', '\n'}
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var _ N.EarlyConn = (*ClientConn)(nil)
type ClientConn struct {
N.ExtendedConn
key [KeyLength]byte
destination M.Socksaddr
headerWritten bool
}
func NewClientConn(conn net.Conn, key [KeyLength]byte, destination M.Socksaddr) *ClientConn {
return &ClientConn{
ExtendedConn: bufio.NewExtendedConn(conn),
key: key,
destination: destination,
}
}
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func (c *ClientConn) NeedHandshake() bool {
return !c.headerWritten
}
func (c *ClientConn) Write(p []byte) (n int, err error) {
if c.headerWritten {
return c.ExtendedConn.Write(p)
}
err = ClientHandshake(c.ExtendedConn, c.key, c.destination, p)
if err != nil {
return
}
n = len(p)
c.headerWritten = true
return
}
func (c *ClientConn) WriteBuffer(buffer *buf.Buffer) error {
if c.headerWritten {
return c.ExtendedConn.WriteBuffer(buffer)
}
err := ClientHandshakeBuffer(c.ExtendedConn, c.key, c.destination, buffer)
if err != nil {
return err
}
c.headerWritten = true
return nil
}
func (c *ClientConn) FrontHeadroom() int {
if !c.headerWritten {
return KeyLength + 5 + M.MaxSocksaddrLength
}
return 0
}
func (c *ClientConn) Upstream() any {
return c.ExtendedConn
}
type ClientPacketConn struct {
net.Conn
key [KeyLength]byte
headerWritten bool
}
func NewClientPacketConn(conn net.Conn, key [KeyLength]byte) *ClientPacketConn {
return &ClientPacketConn{
Conn: conn,
key: key,
}
}
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func (c *ClientPacketConn) NeedHandshake() bool {
return !c.headerWritten
}
func (c *ClientPacketConn) ReadPacket(buffer *buf.Buffer) (M.Socksaddr, error) {
return ReadPacket(c.Conn, buffer)
}
func (c *ClientPacketConn) WritePacket(buffer *buf.Buffer, destination M.Socksaddr) error {
if !c.headerWritten {
err := ClientHandshakePacket(c.Conn, c.key, destination, buffer)
c.headerWritten = true
return err
}
return WritePacket(c.Conn, buffer, destination)
}
func (c *ClientPacketConn) ReadFrom(p []byte) (n int, addr net.Addr, err error) {
buffer := buf.With(p)
destination, err := c.ReadPacket(buffer)
if err != nil {
return
}
n = buffer.Len()
if destination.IsFqdn() {
addr = destination
} else {
addr = destination.UDPAddr()
}
return
}
func (c *ClientPacketConn) WriteTo(p []byte, addr net.Addr) (n int, err error) {
return bufio.WritePacket(c, p, addr)
}
func (c *ClientPacketConn) Read(p []byte) (n int, err error) {
n, _, err = c.ReadFrom(p)
return
}
func (c *ClientPacketConn) Write(p []byte) (n int, err error) {
return 0, os.ErrInvalid
}
func (c *ClientPacketConn) FrontHeadroom() int {
if !c.headerWritten {
return KeyLength + 2*M.MaxSocksaddrLength + 9
}
return M.MaxSocksaddrLength + 4
}
func (c *ClientPacketConn) Upstream() any {
return c.Conn
}
func Key(password string) [KeyLength]byte {
var key [KeyLength]byte
hash := sha256.New224()
common.Must1(hash.Write([]byte(password)))
hex.Encode(key[:], hash.Sum(nil))
return key
}
func ClientHandshakeRaw(conn net.Conn, key [KeyLength]byte, command byte, destination M.Socksaddr, payload []byte) error {
_, err := conn.Write(key[:])
if err != nil {
return err
}
_, err = conn.Write(CRLF)
if err != nil {
return err
}
_, err = conn.Write([]byte{command})
if err != nil {
return err
}
err = M.SocksaddrSerializer.WriteAddrPort(conn, destination)
if err != nil {
return err
}
_, err = conn.Write(CRLF)
if err != nil {
return err
}
if len(payload) > 0 {
_, err = conn.Write(payload)
if err != nil {
return err
}
}
return nil
}
func ClientHandshake(conn net.Conn, key [KeyLength]byte, destination M.Socksaddr, payload []byte) error {
headerLen := KeyLength + M.SocksaddrSerializer.AddrPortLen(destination) + 5
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header := buf.NewSize(headerLen + len(payload))
defer header.Release()
common.Must1(header.Write(key[:]))
common.Must1(header.Write(CRLF))
common.Must(header.WriteByte(CommandTCP))
common.Must(M.SocksaddrSerializer.WriteAddrPort(header, destination))
common.Must1(header.Write(CRLF))
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common.Must1(header.Write(payload))
_, err := conn.Write(header.Bytes())
if err != nil {
return E.Cause(err, "write request")
}
return nil
}
func ClientHandshakeBuffer(conn net.Conn, key [KeyLength]byte, destination M.Socksaddr, payload *buf.Buffer) error {
header := buf.With(payload.ExtendHeader(KeyLength + M.SocksaddrSerializer.AddrPortLen(destination) + 5))
common.Must1(header.Write(key[:]))
common.Must1(header.Write(CRLF))
common.Must(header.WriteByte(CommandTCP))
common.Must(M.SocksaddrSerializer.WriteAddrPort(header, destination))
common.Must1(header.Write(CRLF))
_, err := conn.Write(payload.Bytes())
if err != nil {
return E.Cause(err, "write request")
}
return nil
}
func ClientHandshakePacket(conn net.Conn, key [KeyLength]byte, destination M.Socksaddr, payload *buf.Buffer) error {
headerLen := KeyLength + 2*M.SocksaddrSerializer.AddrPortLen(destination) + 9
payloadLen := payload.Len()
var header *buf.Buffer
var writeHeader bool
if payload.Start() >= headerLen {
header = buf.With(payload.ExtendHeader(headerLen))
} else {
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header = buf.NewSize(headerLen)
defer header.Release()
writeHeader = true
}
common.Must1(header.Write(key[:]))
common.Must1(header.Write(CRLF))
common.Must(header.WriteByte(CommandUDP))
common.Must(M.SocksaddrSerializer.WriteAddrPort(header, destination))
common.Must1(header.Write(CRLF))
common.Must(M.SocksaddrSerializer.WriteAddrPort(header, destination))
common.Must(binary.Write(header, binary.BigEndian, uint16(payloadLen)))
common.Must1(header.Write(CRLF))
if writeHeader {
_, err := conn.Write(header.Bytes())
if err != nil {
return E.Cause(err, "write request")
}
}
_, err := conn.Write(payload.Bytes())
if err != nil {
return E.Cause(err, "write payload")
}
return nil
}
func ReadPacket(conn net.Conn, buffer *buf.Buffer) (M.Socksaddr, error) {
destination, err := M.SocksaddrSerializer.ReadAddrPort(conn)
if err != nil {
return M.Socksaddr{}, E.Cause(err, "read destination")
}
var length uint16
err = binary.Read(conn, binary.BigEndian, &length)
if err != nil {
return M.Socksaddr{}, E.Cause(err, "read chunk length")
}
err = rw.SkipN(conn, 2)
if err != nil {
return M.Socksaddr{}, E.Cause(err, "skip crlf")
}
_, err = buffer.ReadFullFrom(conn, int(length))
return destination.Unwrap(), err
}
func WritePacket(conn net.Conn, buffer *buf.Buffer, destination M.Socksaddr) error {
defer buffer.Release()
bufferLen := buffer.Len()
header := buf.With(buffer.ExtendHeader(M.SocksaddrSerializer.AddrPortLen(destination) + 4))
common.Must(M.SocksaddrSerializer.WriteAddrPort(header, destination))
common.Must(binary.Write(header, binary.BigEndian, uint16(bufferLen)))
common.Must1(header.Write(CRLF))
_, err := conn.Write(buffer.Bytes())
if err != nil {
return E.Cause(err, "write packet")
}
return nil
}