Proxy: Add Hysteria outbound & transport (version 2, udphop) and Salamander udpmask (#5508)

https://github.com/XTLS/Xray-core/issues/3547#issuecomment-3549896520
https://github.com/XTLS/Xray-core/issues/2635#issuecomment-3570871754

proxy/hysteria/client.go

@@ -0,0 +1,263 @@
+package hysteria
+
+import (
+	"context"
+	go_errors "errors"
+	"io"
+	"math/rand"
+
+	"github.com/apernet/quic-go"
+	"github.com/xtls/xray-core/common"
+	"github.com/xtls/xray-core/common/buf"
+	"github.com/xtls/xray-core/common/errors"
+	"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"
+	"github.com/xtls/xray-core/common/task"
+	"github.com/xtls/xray-core/core"
+	"github.com/xtls/xray-core/features/policy"
+	"github.com/xtls/xray-core/transport"
+	"github.com/xtls/xray-core/transport/internet"
+	"github.com/xtls/xray-core/transport/internet/hysteria"
+	"github.com/xtls/xray-core/transport/internet/stat"
+)
+
+type Client struct {
+	server        *protocol.ServerSpec
+	policyManager policy.Manager
+}
+
+func NewClient(ctx context.Context, config *ClientConfig) (*Client, error) {
+	if config.Server == nil {
+		return nil, errors.New(`no target server found`)
+	}
+	server, err := protocol.NewServerSpecFromPB(config.Server)
+	if err != nil {
+		return nil, errors.New("failed to get server spec").Base(err)
+	}
+
+	v := core.MustFromContext(ctx)
+	client := &Client{
+		server:        server,
+		policyManager: v.GetFeature(policy.ManagerType()).(policy.Manager),
+	}
+	return client, nil
+}
+
+func (c *Client) Process(ctx context.Context, link *transport.Link, dialer internet.Dialer) error {
+	outbounds := session.OutboundsFromContext(ctx)
+	ob := outbounds[len(outbounds)-1]
+	if !ob.Target.IsValid() {
+		return errors.New("target not specified")
+	}
+	ob.Name = "hysteria"
+	ob.CanSpliceCopy = 3
+	target := ob.Target
+
+	conn, err := dialer.Dial(ctx, c.server.Destination)
+	if err != nil {
+		return errors.New("failed to find an available destination").AtWarning().Base(err)
+	}
+	defer conn.Close()
+	errors.LogInfo(ctx, "tunneling request to ", target, " via ", target.Network, ":", c.server.Destination.NetAddr())
+
+	var newCtx context.Context
+	var newCancel context.CancelFunc
+	if session.TimeoutOnlyFromContext(ctx) {
+		newCtx, newCancel = context.WithCancel(context.Background())
+	}
+
+	sessionPolicy := c.policyManager.ForLevel(0)
+	ctx, cancel := context.WithCancel(ctx)
+	timer := signal.CancelAfterInactivity(ctx, func() {
+		cancel()
+		if newCancel != nil {
+			newCancel()
+		}
+	}, sessionPolicy.Timeouts.ConnectionIdle)
+
+	if newCtx != nil {
+		ctx = newCtx
+	}
+
+	if target.Network == net.Network_TCP {
+		requestDone := func() error {
+			defer timer.SetTimeout(sessionPolicy.Timeouts.DownlinkOnly)
+			bufferedWriter := buf.NewBufferedWriter(buf.NewWriter(conn))
+			err := WriteTCPRequest(bufferedWriter, target.NetAddr())
+			if err != nil {
+				return errors.New("failed to write request").Base(err)
+			}
+			if err := bufferedWriter.SetBuffered(false); err != nil {
+				return err
+			}
+			return buf.Copy(link.Reader, bufferedWriter, buf.UpdateActivity(timer))
+		}
+
+		responseDone := func() error {
+			defer timer.SetTimeout(sessionPolicy.Timeouts.UplinkOnly)
+			ok, msg, err := ReadTCPResponse(conn)
+			if err != nil {
+				return err
+			}
+			if !ok {
+				return errors.New(msg)
+			}
+			return buf.Copy(buf.NewReader(conn), link.Writer, buf.UpdateActivity(timer))
+		}
+
+		responseDoneAndCloseWriter := task.OnSuccess(responseDone, task.Close(link.Writer))
+		if err := task.Run(ctx, requestDone, responseDoneAndCloseWriter); err != nil {
+			return errors.New("connection ends").Base(err)
+		}
+
+		return nil
+	}
+
+	if target.Network == net.Network_UDP {
+		iConn := stat.TryUnwrapStatsConn(conn)
+		_, ok := iConn.(*hysteria.InterUdpConn)
+		if !ok {
+			return errors.New("udp requires hysteria udp transport")
+		}
+
+		requestDone := func() error {
+			defer timer.SetTimeout(sessionPolicy.Timeouts.DownlinkOnly)
+
+			writer := &UDPWriter{
+				Writer: conn,
+				buf:    make([]byte, MaxUDPSize),
+				addr:   target.NetAddr(),
+			}
+
+			if err := buf.Copy(link.Reader, writer, buf.UpdateActivity(timer)); err != nil {
+				return errors.New("failed to transport all UDP request").Base(err)
+			}
+			return nil
+		}
+
+		responseDone := func() error {
+			defer timer.SetTimeout(sessionPolicy.Timeouts.UplinkOnly)
+
+			reader := &UDPReader{
+				Reader: conn,
+				df:     &Defragger{},
+			}
+
+			if err := buf.Copy(reader, link.Writer, buf.UpdateActivity(timer)); err != nil {
+				return errors.New("failed to transport all UDP response").Base(err)
+			}
+			return nil
+		}
+
+		responseDoneAndCloseWriter := task.OnSuccess(responseDone, task.Close(link.Writer))
+		if err := task.Run(ctx, requestDone, responseDoneAndCloseWriter); err != nil {
+			return errors.New("connection ends").Base(err)
+		}
+
+		return nil
+	}
+
+	return nil
+}
+
+func init() {
+	common.Must(common.RegisterConfig((*ClientConfig)(nil), func(ctx context.Context, config interface{}) (interface{}, error) {
+		return NewClient(ctx, config.(*ClientConfig))
+	}))
+}
+
+type UDPWriter struct {
+	Writer io.Writer
+	buf    []byte
+	addr   string
+}
+
+func (w *UDPWriter) sendMsg(msg *UDPMessage) error {
+	msgN := msg.Serialize(w.buf)
+	if msgN < 0 {
+		// Message larger than buffer, silent drop
+		return nil
+	}
+	_, err := w.Writer.Write(w.buf[:msgN])
+	return err
+}
+
+func (w *UDPWriter) WriteMultiBuffer(mb buf.MultiBuffer) error {
+	for {
+		mb2, b := buf.SplitFirst(mb)
+		mb = mb2
+		if b == nil {
+			break
+		}
+		addr := w.addr
+		if b.UDP != nil {
+			addr = b.UDP.NetAddr()
+		}
+		msg := &UDPMessage{
+			SessionID: 0,
+			PacketID:  0,
+			FragID:    0,
+			FragCount: 1,
+			Addr:      addr,
+			Data:      b.Bytes(),
+		}
+		if err := w.sendMsg(msg); err != nil {
+			var errTooLarge *quic.DatagramTooLargeError
+			if go_errors.As(err, &errTooLarge) {
+				msg.PacketID = uint16(rand.Intn(0xFFFF)) + 1
+				fMsgs := FragUDPMessage(msg, int(errTooLarge.MaxDatagramPayloadSize))
+				for _, fMsg := range fMsgs {
+					err := w.sendMsg(&fMsg)
+					if err != nil {
+						b.Release()
+						buf.ReleaseMulti(mb)
+						return err
+					}
+				}
+			} else {
+				b.Release()
+				buf.ReleaseMulti(mb)
+				return err
+			}
+		}
+		b.Release()
+	}
+	return nil
+}
+
+type UDPReader struct {
+	Reader io.Reader
+	df     *Defragger
+}
+
+func (r *UDPReader) ReadMultiBuffer() (buf.MultiBuffer, error) {
+	for {
+		b := buf.New()
+		_, err := b.ReadFrom(r.Reader)
+		if err != nil {
+			b.Release()
+			return nil, err
+		}
+
+		msg, err := ParseUDPMessage(b.Bytes())
+		if err != nil {
+			b.Release()
+			continue
+		}
+
+		dfMsg := r.df.Feed(msg)
+		if dfMsg == nil {
+			continue
+		}
+
+		dest, _ := net.ParseDestination("udp:" + dfMsg.Addr)
+
+		buffer := buf.New()
+		buffer.Write(dfMsg.Data)
+		buffer.UDP = &dest
+
+		return buf.MultiBuffer{buffer}, nil
+	}
+}

proxy/hysteria/config.go

@@ -0,0 +1,10 @@
+package hysteria
+
+import (
+	"github.com/xtls/xray-core/transport/internet/hysteria/padding"
+)
+
+var (
+	tcpRequestPadding = padding.Padding{Min: 64, Max: 512}
+	// tcpResponsePadding = padding.Padding{Min: 128, Max: 1024}
+)

proxy/hysteria/config.pb.go

@@ -0,0 +1,126 @@
+// Code generated by protoc-gen-go. DO NOT EDIT.
+// versions:
+// 	protoc-gen-go v1.36.10
+// 	protoc        v6.33.1
+// source: proxy/hysteria/config.proto
+
+package hysteria
+
+import (
+	protocol "github.com/xtls/xray-core/common/protocol"
+	protoreflect "google.golang.org/protobuf/reflect/protoreflect"
+	protoimpl "google.golang.org/protobuf/runtime/protoimpl"
+	reflect "reflect"
+	sync "sync"
+	unsafe "unsafe"
+)
+
+const (
+	// Verify that this generated code is sufficiently up-to-date.
+	_ = protoimpl.EnforceVersion(20 - protoimpl.MinVersion)
+	// Verify that runtime/protoimpl is sufficiently up-to-date.
+	_ = protoimpl.EnforceVersion(protoimpl.MaxVersion - 20)
+)
+
+type ClientConfig struct {
+	state         protoimpl.MessageState   `protogen:"open.v1"`
+	Server        *protocol.ServerEndpoint `protobuf:"bytes,1,opt,name=server,proto3" json:"server,omitempty"`
+	unknownFields protoimpl.UnknownFields
+	sizeCache     protoimpl.SizeCache
+}
+
+func (x *ClientConfig) Reset() {
+	*x = ClientConfig{}
+	mi := &file_proxy_hysteria_config_proto_msgTypes[0]
+	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+	ms.StoreMessageInfo(mi)
+}
+
+func (x *ClientConfig) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*ClientConfig) ProtoMessage() {}
+
+func (x *ClientConfig) ProtoReflect() protoreflect.Message {
+	mi := &file_proxy_hysteria_config_proto_msgTypes[0]
+	if x != nil {
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		if ms.LoadMessageInfo() == nil {
+			ms.StoreMessageInfo(mi)
+		}
+		return ms
+	}
+	return mi.MessageOf(x)
+}
+
+// Deprecated: Use ClientConfig.ProtoReflect.Descriptor instead.
+func (*ClientConfig) Descriptor() ([]byte, []int) {
+	return file_proxy_hysteria_config_proto_rawDescGZIP(), []int{0}
+}
+
+func (x *ClientConfig) GetServer() *protocol.ServerEndpoint {
+	if x != nil {
+		return x.Server
+	}
+	return nil
+}
+
+var File_proxy_hysteria_config_proto protoreflect.FileDescriptor
+
+const file_proxy_hysteria_config_proto_rawDesc = "" +
+	"\n" +
+	"\x1bproxy/hysteria/config.proto\x12\x13xray.proxy.hysteria\x1a!common/protocol/server_spec.proto\"L\n" +
+	"\fClientConfig\x12<\n" +
+	"\x06server\x18\x01 \x01(\v2$.xray.common.protocol.ServerEndpointR\x06serverB[\n" +
+	"\x17com.xray.proxy.hysteriaP\x01Z(github.com/xtls/xray-core/proxy/hysteria\xaa\x02\x13Xray.Proxy.Hysteriab\x06proto3"
+
+var (
+	file_proxy_hysteria_config_proto_rawDescOnce sync.Once
+	file_proxy_hysteria_config_proto_rawDescData []byte
+)
+
+func file_proxy_hysteria_config_proto_rawDescGZIP() []byte {
+	file_proxy_hysteria_config_proto_rawDescOnce.Do(func() {
+		file_proxy_hysteria_config_proto_rawDescData = protoimpl.X.CompressGZIP(unsafe.Slice(unsafe.StringData(file_proxy_hysteria_config_proto_rawDesc), len(file_proxy_hysteria_config_proto_rawDesc)))
+	})
+	return file_proxy_hysteria_config_proto_rawDescData
+}
+
+var file_proxy_hysteria_config_proto_msgTypes = make([]protoimpl.MessageInfo, 1)
+var file_proxy_hysteria_config_proto_goTypes = []any{
+	(*ClientConfig)(nil),            // 0: xray.proxy.hysteria.ClientConfig
+	(*protocol.ServerEndpoint)(nil), // 1: xray.common.protocol.ServerEndpoint
+}
+var file_proxy_hysteria_config_proto_depIdxs = []int32{
+	1, // 0: xray.proxy.hysteria.ClientConfig.server:type_name -> xray.common.protocol.ServerEndpoint
+	1, // [1:1] is the sub-list for method output_type
+	1, // [1:1] is the sub-list for method input_type
+	1, // [1:1] is the sub-list for extension type_name
+	1, // [1:1] is the sub-list for extension extendee
+	0, // [0:1] is the sub-list for field type_name
+}
+
+func init() { file_proxy_hysteria_config_proto_init() }
+func file_proxy_hysteria_config_proto_init() {
+	if File_proxy_hysteria_config_proto != nil {
+		return
+	}
+	type x struct{}
+	out := protoimpl.TypeBuilder{
+		File: protoimpl.DescBuilder{
+			GoPackagePath: reflect.TypeOf(x{}).PkgPath(),
+			RawDescriptor: unsafe.Slice(unsafe.StringData(file_proxy_hysteria_config_proto_rawDesc), len(file_proxy_hysteria_config_proto_rawDesc)),
+			NumEnums:      0,
+			NumMessages:   1,
+			NumExtensions: 0,
+			NumServices:   0,
+		},
+		GoTypes:           file_proxy_hysteria_config_proto_goTypes,
+		DependencyIndexes: file_proxy_hysteria_config_proto_depIdxs,
+		MessageInfos:      file_proxy_hysteria_config_proto_msgTypes,
+	}.Build()
+	File_proxy_hysteria_config_proto = out.File
+	file_proxy_hysteria_config_proto_goTypes = nil
+	file_proxy_hysteria_config_proto_depIdxs = nil
+}

proxy/hysteria/config.proto

@@ -0,0 +1,13 @@
+syntax = "proto3";
+
+package xray.proxy.hysteria;
+option csharp_namespace = "Xray.Proxy.Hysteria";
+option go_package = "github.com/xtls/xray-core/proxy/hysteria";
+option java_package = "com.xray.proxy.hysteria";
+option java_multiple_files = true;
+
+import "common/protocol/server_spec.proto";
+
+message ClientConfig {
+  xray.common.protocol.ServerEndpoint server = 1;
+}

proxy/hysteria/frag.go

@@ -0,0 +1,73 @@
+package hysteria
+
+func FragUDPMessage(m *UDPMessage, maxSize int) []UDPMessage {
+	if m.Size() <= maxSize {
+		return []UDPMessage{*m}
+	}
+	fullPayload := m.Data
+	maxPayloadSize := maxSize - m.HeaderSize()
+	off := 0
+	fragID := uint8(0)
+	fragCount := uint8((len(fullPayload) + maxPayloadSize - 1) / maxPayloadSize) // round up
+	frags := make([]UDPMessage, fragCount)
+	for off < len(fullPayload) {
+		payloadSize := len(fullPayload) - off
+		if payloadSize > maxPayloadSize {
+			payloadSize = maxPayloadSize
+		}
+		frag := *m
+		frag.FragID = fragID
+		frag.FragCount = fragCount
+		frag.Data = fullPayload[off : off+payloadSize]
+		frags[fragID] = frag
+		off += payloadSize
+		fragID++
+	}
+	return frags
+}
+
+// Defragger handles the defragmentation of UDP messages.
+// The current implementation can only handle one packet ID at a time.
+// If another packet arrives before a packet has received all fragments
+// in their entirety, any previous state is discarded.
+type Defragger struct {
+	pktID uint16
+	frags []*UDPMessage
+	count uint8
+	size  int // data size
+}
+
+func (d *Defragger) Feed(m *UDPMessage) *UDPMessage {
+	if m.FragCount <= 1 {
+		return m
+	}
+	if m.FragID >= m.FragCount {
+		// wtf is this?
+		return nil
+	}
+	if m.PacketID != d.pktID || m.FragCount != uint8(len(d.frags)) {
+		// new message, clear previous state
+		d.pktID = m.PacketID
+		d.frags = make([]*UDPMessage, m.FragCount)
+		d.frags[m.FragID] = m
+		d.count = 1
+		d.size = len(m.Data)
+	} else if d.frags[m.FragID] == nil {
+		d.frags[m.FragID] = m
+		d.count++
+		d.size += len(m.Data)
+		if int(d.count) == len(d.frags) {
+			// all fragments received, assemble
+			data := make([]byte, d.size)
+			off := 0
+			for _, frag := range d.frags {
+				off += copy(data[off:], frag.Data)
+			}
+			m.Data = data
+			m.FragID = 0
+			m.FragCount = 1
+			return m
+		}
+	}
+	return nil
+}

proxy/hysteria/protocol.go

@@ -0,0 +1,204 @@
+package hysteria
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+	"io"
+
+	"github.com/apernet/quic-go/quicvarint"
+	"github.com/xtls/xray-core/common/errors"
+)
+
+const (
+	FrameTypeTCPRequest = 0x401
+
+	// Max length values are for preventing DoS attacks
+
+	MaxAddressLength = 2048
+	MaxMessageLength = 2048
+	MaxPaddingLength = 4096
+
+	MaxUDPSize = 4096
+
+	maxVarInt1 = 63
+	maxVarInt2 = 16383
+	maxVarInt4 = 1073741823
+	maxVarInt8 = 4611686018427387903
+)
+
+// TCPRequest format:
+// 0x401 (QUIC varint)
+// Address length (QUIC varint)
+// Address (bytes)
+// Padding length (QUIC varint)
+// Padding (bytes)
+
+func WriteTCPRequest(w io.Writer, addr string) error {
+	padding := tcpRequestPadding.String()
+	paddingLen := len(padding)
+	addrLen := len(addr)
+	sz := int(quicvarint.Len(FrameTypeTCPRequest)) +
+		int(quicvarint.Len(uint64(addrLen))) + addrLen +
+		int(quicvarint.Len(uint64(paddingLen))) + paddingLen
+	buf := make([]byte, sz)
+	i := varintPut(buf, FrameTypeTCPRequest)
+	i += varintPut(buf[i:], uint64(addrLen))
+	i += copy(buf[i:], addr)
+	i += varintPut(buf[i:], uint64(paddingLen))
+	copy(buf[i:], padding)
+	_, err := w.Write(buf)
+	return err
+}
+
+// TCPResponse format:
+// Status (byte, 0=ok, 1=error)
+// Message length (QUIC varint)
+// Message (bytes)
+// Padding length (QUIC varint)
+// Padding (bytes)
+
+func ReadTCPResponse(r io.Reader) (bool, string, error) {
+	var status [1]byte
+	if _, err := io.ReadFull(r, status[:]); err != nil {
+		return false, "", err
+	}
+	bReader := quicvarint.NewReader(r)
+	msgLen, err := quicvarint.Read(bReader)
+	if err != nil {
+		return false, "", err
+	}
+	if msgLen > MaxMessageLength {
+		return false, "", errors.New("invalid message length")
+	}
+	var msgBuf []byte
+	// No message is fine
+	if msgLen > 0 {
+		msgBuf = make([]byte, msgLen)
+		_, err = io.ReadFull(r, msgBuf)
+		if err != nil {
+			return false, "", err
+		}
+	}
+	paddingLen, err := quicvarint.Read(bReader)
+	if err != nil {
+		return false, "", err
+	}
+	if paddingLen > MaxPaddingLength {
+		return false, "", errors.New("invalid padding length")
+	}
+	if paddingLen > 0 {
+		_, err = io.CopyN(io.Discard, r, int64(paddingLen))
+		if err != nil {
+			return false, "", err
+		}
+	}
+	return status[0] == 0, string(msgBuf), nil
+}
+
+// UDPMessage format:
+// Session ID (uint32 BE)
+// Packet ID (uint16 BE)
+// Fragment ID (uint8)
+// Fragment count (uint8)
+// Address length (QUIC varint)
+// Address (bytes)
+// Data...
+
+type UDPMessage struct {
+	SessionID uint32 // 4
+	PacketID  uint16 // 2
+	FragID    uint8  // 1
+	FragCount uint8  // 1
+	Addr      string // varint + bytes
+	Data      []byte
+}
+
+func (m *UDPMessage) HeaderSize() int {
+	lAddr := len(m.Addr)
+	return 4 + 2 + 1 + 1 + int(quicvarint.Len(uint64(lAddr))) + lAddr
+}
+
+func (m *UDPMessage) Size() int {
+	return m.HeaderSize() + len(m.Data)
+}
+
+func (m *UDPMessage) Serialize(buf []byte) int {
+	// Make sure the buffer is big enough
+	if len(buf) < m.Size() {
+		return -1
+	}
+	// binary.BigEndian.PutUint32(buf, m.SessionID)
+	binary.BigEndian.PutUint16(buf[4:], m.PacketID)
+	buf[6] = m.FragID
+	buf[7] = m.FragCount
+	i := varintPut(buf[8:], uint64(len(m.Addr)))
+	i += copy(buf[8+i:], m.Addr)
+	i += copy(buf[8+i:], m.Data)
+	return 8 + i
+}
+
+func ParseUDPMessage(msg []byte) (*UDPMessage, error) {
+	m := &UDPMessage{}
+	buf := bytes.NewBuffer(msg)
+	if err := binary.Read(buf, binary.BigEndian, &m.SessionID); err != nil {
+		return nil, err
+	}
+	if err := binary.Read(buf, binary.BigEndian, &m.PacketID); err != nil {
+		return nil, err
+	}
+	if err := binary.Read(buf, binary.BigEndian, &m.FragID); err != nil {
+		return nil, err
+	}
+	if err := binary.Read(buf, binary.BigEndian, &m.FragCount); err != nil {
+		return nil, err
+	}
+	lAddr, err := quicvarint.Read(buf)
+	if err != nil {
+		return nil, err
+	}
+	if lAddr == 0 || lAddr > MaxMessageLength {
+		return nil, errors.New("invalid address length")
+	}
+	bs := buf.Bytes()
+	if len(bs) <= int(lAddr) {
+		// We use <= instead of < here as we expect at least one byte of data after the address
+		return nil, errors.New("invalid message length")
+	}
+	m.Addr = string(bs[:lAddr])
+	m.Data = bs[lAddr:]
+	return m, nil
+}
+
+// varintPut is like quicvarint.Append, but instead of appending to a slice,
+// it writes to a fixed-size buffer. Returns the number of bytes written.
+func varintPut(b []byte, i uint64) int {
+	if i <= maxVarInt1 {
+		b[0] = uint8(i)
+		return 1
+	}
+	if i <= maxVarInt2 {
+		b[0] = uint8(i>>8) | 0x40
+		b[1] = uint8(i)
+		return 2
+	}
+	if i <= maxVarInt4 {
+		b[0] = uint8(i>>24) | 0x80
+		b[1] = uint8(i >> 16)
+		b[2] = uint8(i >> 8)
+		b[3] = uint8(i)
+		return 4
+	}
+	if i <= maxVarInt8 {
+		b[0] = uint8(i>>56) | 0xc0
+		b[1] = uint8(i >> 48)
+		b[2] = uint8(i >> 40)
+		b[3] = uint8(i >> 32)
+		b[4] = uint8(i >> 24)
+		b[5] = uint8(i >> 16)
+		b[6] = uint8(i >> 8)
+		b[7] = uint8(i)
+		return 8
+	}
+	panic(fmt.Sprintf("%#x doesn't fit into 62 bits", i))
+}