package trojan import ( "encoding/binary" "io" "github.com/v2fly/v2ray-core/v4/common/buf" "github.com/v2fly/v2ray-core/v4/common/net" "github.com/v2fly/v2ray-core/v4/common/protocol" ) var ( crlf = []byte{'\r', '\n'} addrParser = protocol.NewAddressParser( protocol.AddressFamilyByte(0x01, net.AddressFamilyIPv4), protocol.AddressFamilyByte(0x04, net.AddressFamilyIPv6), protocol.AddressFamilyByte(0x03, net.AddressFamilyDomain), ) ) const ( maxLength = 8192 commandTCP byte = 1 commandUDP byte = 3 ) // ConnWriter is TCP Connection Writer Wrapper for trojan protocol type ConnWriter struct { io.Writer Target net.Destination Account *MemoryAccount headerSent bool } // Write implements io.Writer func (c *ConnWriter) Write(p []byte) (n int, err error) { if !c.headerSent { if err := c.writeHeader(); err != nil { return 0, newError("failed to write request header").Base(err) } } return c.Writer.Write(p) } // WriteMultiBuffer implements buf.Writer func (c *ConnWriter) WriteMultiBuffer(mb buf.MultiBuffer) error { defer buf.ReleaseMulti(mb) for _, b := range mb { if !b.IsEmpty() { if _, err := c.Write(b.Bytes()); err != nil { return err } } } return nil } func (c *ConnWriter) writeHeader() error { buffer := buf.StackNew() defer buffer.Release() command := commandTCP if c.Target.Network == net.Network_UDP { command = commandUDP } if _, err := buffer.Write(c.Account.Key); err != nil { return err } if _, err := buffer.Write(crlf); err != nil { return err } if err := buffer.WriteByte(command); err != nil { return err } if err := addrParser.WriteAddressPort(&buffer, c.Target.Address, c.Target.Port); err != nil { return err } if _, err := buffer.Write(crlf); err != nil { return err } _, err := c.Writer.Write(buffer.Bytes()) if err == nil { c.headerSent = true } return err } // PacketWriter UDP Connection Writer Wrapper for trojan protocol type PacketWriter struct { io.Writer Target net.Destination } // WriteMultiBuffer implements buf.Writer func (w *PacketWriter) WriteMultiBuffer(mb buf.MultiBuffer) error { b := make([]byte, maxLength) for !mb.IsEmpty() { var length int mb, length = buf.SplitBytes(mb, b) if _, err := w.writePacket(b[:length], w.Target); err != nil { buf.ReleaseMulti(mb) return err } } return nil } // WriteMultiBufferWithMetadata writes udp packet with destination specified func (w *PacketWriter) WriteMultiBufferWithMetadata(mb buf.MultiBuffer, dest net.Destination) error { b := make([]byte, maxLength) for !mb.IsEmpty() { var length int mb, length = buf.SplitBytes(mb, b) if _, err := w.writePacket(b[:length], dest); err != nil { buf.ReleaseMulti(mb) return err } } return nil } func (w *PacketWriter) writePacket(payload []byte, dest net.Destination) (int, error) { // nolint: unparam buffer := buf.StackNew() defer buffer.Release() length := len(payload) lengthBuf := [2]byte{} binary.BigEndian.PutUint16(lengthBuf[:], uint16(length)) if err := addrParser.WriteAddressPort(&buffer, dest.Address, dest.Port); err != nil { return 0, err } if _, err := buffer.Write(lengthBuf[:]); err != nil { return 0, err } if _, err := buffer.Write(crlf); err != nil { return 0, err } if _, err := buffer.Write(payload); err != nil { return 0, err } _, err := w.Write(buffer.Bytes()) if err != nil { return 0, err } return length, nil } // ConnReader is TCP Connection Reader Wrapper for trojan protocol type ConnReader struct { io.Reader Target net.Destination headerParsed bool } // ParseHeader parses the trojan protocol header func (c *ConnReader) ParseHeader() error { var crlf [2]byte var command [1]byte var hash [56]byte if _, err := io.ReadFull(c.Reader, hash[:]); err != nil { return newError("failed to read user hash").Base(err) } if _, err := io.ReadFull(c.Reader, crlf[:]); err != nil { return newError("failed to read crlf").Base(err) } if _, err := io.ReadFull(c.Reader, command[:]); err != nil { return newError("failed to read command").Base(err) } network := net.Network_TCP if command[0] == commandUDP { network = net.Network_UDP } addr, port, err := addrParser.ReadAddressPort(nil, c.Reader) if err != nil { return newError("failed to read address and port").Base(err) } c.Target = net.Destination{Network: network, Address: addr, Port: port} if _, err := io.ReadFull(c.Reader, crlf[:]); err != nil { return newError("failed to read crlf").Base(err) } c.headerParsed = true return nil } // Read implements io.Reader func (c *ConnReader) Read(p []byte) (int, error) { if !c.headerParsed { if err := c.ParseHeader(); err != nil { return 0, err } } return c.Reader.Read(p) } // ReadMultiBuffer implements buf.Reader func (c *ConnReader) ReadMultiBuffer() (buf.MultiBuffer, error) { b := buf.New() _, err := b.ReadFrom(c) return buf.MultiBuffer{b}, err } // PacketPayload combines udp payload and destination type PacketPayload struct { Target net.Destination Buffer buf.MultiBuffer } // PacketReader is UDP Connection Reader Wrapper for trojan protocol type PacketReader struct { io.Reader } // ReadMultiBuffer implements buf.Reader func (r *PacketReader) ReadMultiBuffer() (buf.MultiBuffer, error) { p, err := r.ReadMultiBufferWithMetadata() if p != nil { return p.Buffer, err } return nil, err } // ReadMultiBufferWithMetadata reads udp packet with destination func (r *PacketReader) ReadMultiBufferWithMetadata() (*PacketPayload, error) { addr, port, err := addrParser.ReadAddressPort(nil, r) if err != nil { return nil, newError("failed to read address and port").Base(err) } var lengthBuf [2]byte if _, err := io.ReadFull(r, lengthBuf[:]); err != nil { return nil, newError("failed to read payload length").Base(err) } remain := int(binary.BigEndian.Uint16(lengthBuf[:])) if remain > maxLength { return nil, newError("oversize payload") } var crlf [2]byte if _, err := io.ReadFull(r, crlf[:]); err != nil { return nil, newError("failed to read crlf").Base(err) } dest := net.UDPDestination(addr, port) var mb buf.MultiBuffer for remain > 0 { length := buf.Size if remain < length { length = remain } b := buf.New() mb = append(mb, b) n, err := b.ReadFullFrom(r, int32(length)) if err != nil { buf.ReleaseMulti(mb) return nil, newError("failed to read payload").Base(err) } remain -= int(n) } return &PacketPayload{Target: dest, Buffer: mb}, nil }