Xray-core/proxy/proxy.go

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// Package proxy contains all proxies used by Xray.
//
// To implement an inbound or outbound proxy, one needs to do the following:
// 1. Implement the interface(s) below.
// 2. Register a config creator through common.RegisterConfig.
package proxy
import (
"bytes"
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"context"
"crypto/rand"
"io"
"math/big"
"runtime"
"strconv"
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"time"
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"github.com/pires/go-proxyproto"
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"github.com/xtls/xray-core/app/dispatcher"
"github.com/xtls/xray-core/common/buf"
"github.com/xtls/xray-core/common/errors"
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"github.com/xtls/xray-core/common/net"
"github.com/xtls/xray-core/common/protocol"
"github.com/xtls/xray-core/common/session"
"github.com/xtls/xray-core/common/signal"
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"github.com/xtls/xray-core/features/routing"
"github.com/xtls/xray-core/features/stats"
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"github.com/xtls/xray-core/transport"
"github.com/xtls/xray-core/transport/internet"
"github.com/xtls/xray-core/transport/internet/reality"
"github.com/xtls/xray-core/transport/internet/stat"
"github.com/xtls/xray-core/transport/internet/tls"
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)
var (
Tls13SupportedVersions = []byte{0x00, 0x2b, 0x00, 0x02, 0x03, 0x04}
TlsClientHandShakeStart = []byte{0x16, 0x03}
TlsServerHandShakeStart = []byte{0x16, 0x03, 0x03}
TlsApplicationDataStart = []byte{0x17, 0x03, 0x03}
Tls13CipherSuiteDic = map[uint16]string{
0x1301: "TLS_AES_128_GCM_SHA256",
0x1302: "TLS_AES_256_GCM_SHA384",
0x1303: "TLS_CHACHA20_POLY1305_SHA256",
0x1304: "TLS_AES_128_CCM_SHA256",
0x1305: "TLS_AES_128_CCM_8_SHA256",
}
)
const (
TlsHandshakeTypeClientHello byte = 0x01
TlsHandshakeTypeServerHello byte = 0x02
CommandPaddingContinue byte = 0x00
CommandPaddingEnd byte = 0x01
CommandPaddingDirect byte = 0x02
)
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// An Inbound processes inbound connections.
type Inbound interface {
// Network returns a list of networks that this inbound supports. Connections with not-supported networks will not be passed into Process().
Network() []net.Network
// Process processes a connection of given network. If necessary, the Inbound can dispatch the connection to an Outbound.
Process(context.Context, net.Network, stat.Connection, routing.Dispatcher) error
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}
// An Outbound process outbound connections.
type Outbound interface {
// Process processes the given connection. The given dialer may be used to dial a system outbound connection.
Process(context.Context, *transport.Link, internet.Dialer) error
}
// UserManager is the interface for Inbounds and Outbounds that can manage their users.
type UserManager interface {
// AddUser adds a new user.
AddUser(context.Context, *protocol.MemoryUser) error
// RemoveUser removes a user by email.
RemoveUser(context.Context, string) error
}
type GetInbound interface {
GetInbound() Inbound
}
type GetOutbound interface {
GetOutbound() Outbound
}
// TrafficState is used to track uplink and downlink of one connection
// It is used by XTLS to determine if switch to raw copy mode, It is used by Vision to calculate padding
type TrafficState struct {
UserUUID []byte
NumberOfPacketToFilter int
EnableXtls bool
IsTLS12orAbove bool
IsTLS bool
Cipher uint16
RemainingServerHello int32
// reader link state
WithinPaddingBuffers bool
ReaderSwitchToDirectCopy bool
RemainingCommand int32
RemainingContent int32
RemainingPadding int32
CurrentCommand int
// write link state
IsPadding bool
WriterSwitchToDirectCopy bool
}
func NewTrafficState(userUUID []byte) *TrafficState {
return &TrafficState{
UserUUID: userUUID,
NumberOfPacketToFilter: 8,
EnableXtls: false,
IsTLS12orAbove: false,
IsTLS: false,
Cipher: 0,
RemainingServerHello: -1,
WithinPaddingBuffers: true,
ReaderSwitchToDirectCopy: false,
RemainingCommand: -1,
RemainingContent: -1,
RemainingPadding: -1,
CurrentCommand: 0,
IsPadding: true,
WriterSwitchToDirectCopy: false,
}
}
// VisionReader is used to read xtls vision protocol
// Note Vision probably only make sense as the inner most layer of reader, since it need assess traffic state from origin proxy traffic
type VisionReader struct {
buf.Reader
trafficState *TrafficState
ctx context.Context
}
func NewVisionReader(reader buf.Reader, state *TrafficState, context context.Context) *VisionReader {
return &VisionReader{
Reader: reader,
trafficState: state,
ctx: context,
}
}
func (w *VisionReader) ReadMultiBuffer() (buf.MultiBuffer, error) {
buffer, err := w.Reader.ReadMultiBuffer()
if !buffer.IsEmpty() {
if w.trafficState.WithinPaddingBuffers || w.trafficState.NumberOfPacketToFilter > 0 {
mb2 := make(buf.MultiBuffer, 0, len(buffer))
for _, b := range buffer {
newbuffer := XtlsUnpadding(b, w.trafficState, w.ctx)
if newbuffer.Len() > 0 {
mb2 = append(mb2, newbuffer)
}
}
buffer = mb2
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if w.trafficState.RemainingContent > 0 || w.trafficState.RemainingPadding > 0 || w.trafficState.CurrentCommand == 0 {
w.trafficState.WithinPaddingBuffers = true
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} else if w.trafficState.CurrentCommand == 1 {
w.trafficState.WithinPaddingBuffers = false
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} else if w.trafficState.CurrentCommand == 2 {
w.trafficState.WithinPaddingBuffers = false
w.trafficState.ReaderSwitchToDirectCopy = true
} else {
newError("XtlsRead unknown command ", w.trafficState.CurrentCommand, buffer.Len()).WriteToLog(session.ExportIDToError(w.ctx))
}
}
if w.trafficState.NumberOfPacketToFilter > 0 {
XtlsFilterTls(buffer, w.trafficState, w.ctx)
}
}
return buffer, err
}
// VisionWriter is used to write xtls vision protocol
// Note Vision probably only make sense as the inner most layer of writer, since it need assess traffic state from origin proxy traffic
type VisionWriter struct {
buf.Writer
trafficState *TrafficState
ctx context.Context
writeOnceUserUUID []byte
}
func NewVisionWriter(writer buf.Writer, state *TrafficState, context context.Context) *VisionWriter {
w := make([]byte, len(state.UserUUID))
copy(w, state.UserUUID)
return &VisionWriter{
Writer: writer,
trafficState: state,
ctx: context,
writeOnceUserUUID: w,
}
}
func (w *VisionWriter) WriteMultiBuffer(mb buf.MultiBuffer) error {
if w.trafficState.NumberOfPacketToFilter > 0 {
XtlsFilterTls(mb, w.trafficState, w.ctx)
}
if w.trafficState.IsPadding {
if len(mb) == 1 && mb[0] == nil {
mb[0] = XtlsPadding(nil, CommandPaddingContinue, &w.writeOnceUserUUID, true, w.ctx) // we do a long padding to hide vless header
return w.Writer.WriteMultiBuffer(mb)
}
mb = ReshapeMultiBuffer(w.ctx, mb)
longPadding := w.trafficState.IsTLS
for i, b := range mb {
if w.trafficState.IsTLS && b.Len() >= 6 && bytes.Equal(TlsApplicationDataStart, b.BytesTo(3)) {
if w.trafficState.EnableXtls {
w.trafficState.WriterSwitchToDirectCopy = true
}
var command byte = CommandPaddingContinue
if i == len(mb) - 1 {
command = CommandPaddingEnd
if w.trafficState.EnableXtls {
command = CommandPaddingDirect
}
}
mb[i] = XtlsPadding(b, command, &w.writeOnceUserUUID, true, w.ctx)
w.trafficState.IsPadding = false // padding going to end
longPadding = false
continue
} else if !w.trafficState.IsTLS12orAbove && w.trafficState.NumberOfPacketToFilter <= 1 { // For compatibility with earlier vision receiver, we finish padding 1 packet early
w.trafficState.IsPadding = false
mb[i] = XtlsPadding(b, CommandPaddingEnd, &w.writeOnceUserUUID, longPadding, w.ctx)
break
}
var command byte = CommandPaddingContinue
if i == len(mb) - 1 && !w.trafficState.IsPadding {
command = CommandPaddingEnd
if w.trafficState.EnableXtls {
command = CommandPaddingDirect
}
}
mb[i] = XtlsPadding(b, command, &w.writeOnceUserUUID, longPadding, w.ctx)
}
}
return w.Writer.WriteMultiBuffer(mb)
}
// ReshapeMultiBuffer prepare multi buffer for padding stucture (max 21 bytes)
func ReshapeMultiBuffer(ctx context.Context, buffer buf.MultiBuffer) buf.MultiBuffer {
needReshape := 0
for _, b := range buffer {
if b.Len() >= buf.Size-21 {
needReshape += 1
}
}
if needReshape == 0 {
return buffer
}
mb2 := make(buf.MultiBuffer, 0, len(buffer)+needReshape)
toPrint := ""
for i, buffer1 := range buffer {
if buffer1.Len() >= buf.Size-21 {
index := int32(bytes.LastIndex(buffer1.Bytes(), TlsApplicationDataStart))
if index < 21 || index > buf.Size-21 {
index = buf.Size / 2
}
buffer2 := buf.New()
buffer2.Write(buffer1.BytesFrom(index))
buffer1.Resize(0, index)
mb2 = append(mb2, buffer1, buffer2)
toPrint += " " + strconv.Itoa(int(buffer1.Len())) + " " + strconv.Itoa(int(buffer2.Len()))
} else {
mb2 = append(mb2, buffer1)
toPrint += " " + strconv.Itoa(int(buffer1.Len()))
}
buffer[i] = nil
}
buffer = buffer[:0]
newError("ReshapeMultiBuffer ", toPrint).WriteToLog(session.ExportIDToError(ctx))
return mb2
}
// XtlsPadding add padding to eliminate length siganature during tls handshake
func XtlsPadding(b *buf.Buffer, command byte, userUUID *[]byte, longPadding bool, ctx context.Context) *buf.Buffer {
var contentLen int32 = 0
var paddingLen int32 = 0
if b != nil {
contentLen = b.Len()
}
if contentLen < 900 && longPadding {
l, err := rand.Int(rand.Reader, big.NewInt(500))
if err != nil {
newError("failed to generate padding").Base(err).WriteToLog(session.ExportIDToError(ctx))
}
paddingLen = int32(l.Int64()) + 900 - contentLen
} else {
l, err := rand.Int(rand.Reader, big.NewInt(256))
if err != nil {
newError("failed to generate padding").Base(err).WriteToLog(session.ExportIDToError(ctx))
}
paddingLen = int32(l.Int64())
}
if paddingLen > buf.Size-21-contentLen {
paddingLen = buf.Size - 21 - contentLen
}
newbuffer := buf.New()
if userUUID != nil {
newbuffer.Write(*userUUID)
*userUUID = nil
}
newbuffer.Write([]byte{command, byte(contentLen >> 8), byte(contentLen), byte(paddingLen >> 8), byte(paddingLen)})
if b != nil {
newbuffer.Write(b.Bytes())
b.Release()
b = nil
}
newbuffer.Extend(paddingLen)
newError("XtlsPadding ", contentLen, " ", paddingLen, " ", command).WriteToLog(session.ExportIDToError(ctx))
return newbuffer
}
// XtlsUnpadding remove padding and parse command
func XtlsUnpadding(b *buf.Buffer, s *TrafficState, ctx context.Context) *buf.Buffer {
if s.RemainingCommand == -1 && s.RemainingContent == -1 && s.RemainingPadding == -1 { // inital state
if b.Len() >= 21 && bytes.Equal(s.UserUUID, b.BytesTo(16)) {
b.Advance(16)
s.RemainingCommand = 5
} else {
return b
}
}
newbuffer := buf.New()
for b.Len() > 0 {
if s.RemainingCommand > 0 {
data, err := b.ReadByte()
if err != nil {
return newbuffer
}
switch s.RemainingCommand {
case 5:
s.CurrentCommand = int(data)
case 4:
s.RemainingContent = int32(data)<<8
case 3:
s.RemainingContent = s.RemainingContent | int32(data)
case 2:
s.RemainingPadding = int32(data)<<8
case 1:
s.RemainingPadding = s.RemainingPadding | int32(data)
newError("Xtls Unpadding new block, content ", s.RemainingContent, " padding ", s.RemainingPadding, " command ", s.CurrentCommand).WriteToLog(session.ExportIDToError(ctx))
}
s.RemainingCommand--
} else if s.RemainingContent > 0 {
len := s.RemainingContent
if b.Len() < len {
len = b.Len()
}
data, err := b.ReadBytes(len)
if err != nil {
return newbuffer
}
newbuffer.Write(data)
s.RemainingContent -= len
} else { // remainingPadding > 0
len := s.RemainingPadding
if b.Len() < len {
len = b.Len()
}
b.Advance(len)
s.RemainingPadding -= len
}
if s.RemainingCommand <= 0 && s.RemainingContent <= 0 && s.RemainingPadding <= 0 { // this block done
if s.CurrentCommand == 0 {
s.RemainingCommand = 5
} else {
s.RemainingCommand = -1 // set to initial state
s.RemainingContent = -1
s.RemainingPadding = -1
if b.Len() > 0 { // shouldn't happen
newbuffer.Write(b.Bytes())
}
break
}
}
}
b.Release()
b = nil
return newbuffer
}
// XtlsFilterTls filter and recognize tls 1.3 and other info
func XtlsFilterTls(buffer buf.MultiBuffer, trafficState *TrafficState, ctx context.Context) {
for _, b := range buffer {
if b == nil {
continue
}
trafficState.NumberOfPacketToFilter--
if b.Len() >= 6 {
startsBytes := b.BytesTo(6)
if bytes.Equal(TlsServerHandShakeStart, startsBytes[:3]) && startsBytes[5] == TlsHandshakeTypeServerHello {
trafficState.RemainingServerHello = (int32(startsBytes[3])<<8 | int32(startsBytes[4])) + 5
trafficState.IsTLS12orAbove = true
trafficState.IsTLS = true
if b.Len() >= 79 && trafficState.RemainingServerHello >= 79 {
sessionIdLen := int32(b.Byte(43))
cipherSuite := b.BytesRange(43+sessionIdLen+1, 43+sessionIdLen+3)
trafficState.Cipher = uint16(cipherSuite[0])<<8 | uint16(cipherSuite[1])
} else {
newError("XtlsFilterTls short server hello, tls 1.2 or older? ", b.Len(), " ", trafficState.RemainingServerHello).WriteToLog(session.ExportIDToError(ctx))
}
} else if bytes.Equal(TlsClientHandShakeStart, startsBytes[:2]) && startsBytes[5] == TlsHandshakeTypeClientHello {
trafficState.IsTLS = true
newError("XtlsFilterTls found tls client hello! ", buffer.Len()).WriteToLog(session.ExportIDToError(ctx))
}
}
if trafficState.RemainingServerHello > 0 {
end := trafficState.RemainingServerHello
if end > b.Len() {
end = b.Len()
}
trafficState.RemainingServerHello -= b.Len()
if bytes.Contains(b.BytesTo(end), Tls13SupportedVersions) {
v, ok := Tls13CipherSuiteDic[trafficState.Cipher]
if !ok {
v = "Old cipher: " + strconv.FormatUint(uint64(trafficState.Cipher), 16)
} else if v != "TLS_AES_128_CCM_8_SHA256" {
trafficState.EnableXtls = true
}
newError("XtlsFilterTls found tls 1.3! ", b.Len(), " ", v).WriteToLog(session.ExportIDToError(ctx))
trafficState.NumberOfPacketToFilter = 0
return
} else if trafficState.RemainingServerHello <= 0 {
newError("XtlsFilterTls found tls 1.2! ", b.Len()).WriteToLog(session.ExportIDToError(ctx))
trafficState.NumberOfPacketToFilter = 0
return
}
newError("XtlsFilterTls inconclusive server hello ", b.Len(), " ", trafficState.RemainingServerHello).WriteToLog(session.ExportIDToError(ctx))
}
if trafficState.NumberOfPacketToFilter <= 0 {
newError("XtlsFilterTls stop filtering", buffer.Len()).WriteToLog(session.ExportIDToError(ctx))
}
}
}
// UnwrapRawConn support unwrap stats, tls, utls, reality and proxyproto conn and get raw tcp conn from it
func UnwrapRawConn(conn net.Conn) (net.Conn, stats.Counter, stats.Counter) {
var readCounter, writerCounter stats.Counter
if conn != nil {
statConn, ok := conn.(*stat.CounterConnection)
if ok {
conn = statConn.Connection
readCounter = statConn.ReadCounter
writerCounter = statConn.WriteCounter
}
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if xc, ok := conn.(*tls.Conn); ok {
conn = xc.NetConn()
} else if utlsConn, ok := conn.(*tls.UConn); ok {
conn = utlsConn.NetConn()
} else if realityConn, ok := conn.(*reality.Conn); ok {
conn = realityConn.NetConn()
} else if realityUConn, ok := conn.(*reality.UConn); ok {
conn = realityUConn.NetConn()
}
if pc, ok := conn.(*proxyproto.Conn); ok {
conn = pc.Raw()
// 8192 > 4096, there is no need to process pc's bufReader
}
}
return conn, readCounter, writerCounter
}
// CopyRawConnIfExist use the most efficient copy method.
// - If caller don't want to turn on splice, do not pass in both reader conn and writer conn
// - writer are from *transport.Link
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func CopyRawConnIfExist(ctx context.Context, readerConn net.Conn, writerConn net.Conn, writer buf.Writer, timer *signal.ActivityTimer) error {
readerConn, readCounter, _ := UnwrapRawConn(readerConn)
writerConn, _, writeCounter := UnwrapRawConn(writerConn)
reader := buf.NewReader(readerConn)
if runtime.GOOS != "linux" && runtime.GOOS != "android" {
return readV(ctx, reader, writer, timer, readCounter)
}
tc, ok := writerConn.(*net.TCPConn)
if !ok || readerConn == nil || writerConn == nil {
return readV(ctx, reader, writer, timer, readCounter)
}
inbound := session.InboundFromContext(ctx)
if inbound == nil || inbound.CanSpliceCopy == 3 {
return readV(ctx, reader, writer, timer, readCounter)
}
outbounds := session.OutboundsFromContext(ctx)
if len(outbounds) == 0 {
return readV(ctx, reader, writer, timer, readCounter)
}
for _, ob := range outbounds {
if ob.CanSpliceCopy == 3 {
return readV(ctx, reader, writer, timer, readCounter)
}
}
for {
inbound := session.InboundFromContext(ctx)
outbounds := session.OutboundsFromContext(ctx)
var splice = inbound.CanSpliceCopy == 1
for _, ob := range outbounds {
if ob.CanSpliceCopy != 1 {
splice = false
}
}
if splice {
newError("CopyRawConn splice").WriteToLog(session.ExportIDToError(ctx))
statWriter, _ := writer.(*dispatcher.SizeStatWriter)
//runtime.Gosched() // necessary
time.Sleep(time.Millisecond) // without this, there will be a rare ssl error for freedom splice
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timer.SetTimeout(8 * time.Hour) // prevent leak, just in case
w, err := tc.ReadFrom(readerConn)
if readCounter != nil {
readCounter.Add(w) // outbound stats
}
if writeCounter != nil {
writeCounter.Add(w) // inbound stats
}
if statWriter != nil {
statWriter.Counter.Add(w) // user stats
}
if err != nil && errors.Cause(err) != io.EOF {
return err
}
return nil
}
buffer, err := reader.ReadMultiBuffer()
if !buffer.IsEmpty() {
if readCounter != nil {
readCounter.Add(int64(buffer.Len()))
}
timer.Update()
if werr := writer.WriteMultiBuffer(buffer); werr != nil {
return werr
}
}
if err != nil {
return err
}
}
}
func readV(ctx context.Context, reader buf.Reader, writer buf.Writer, timer signal.ActivityUpdater, readCounter stats.Counter) error {
newError("CopyRawConn readv").WriteToLog(session.ExportIDToError(ctx))
if err := buf.Copy(reader, writer, buf.UpdateActivity(timer), buf.AddToStatCounter(readCounter)); err != nil {
return newError("failed to process response").Base(err)
}
return nil
}