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v2fly/proxy/trojan/protocol.go
2021-02-17 04:31:50 +08:00

282 lines
6.4 KiB
Go

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
}