refine kcp header and security

all.go

@@ -21,8 +21,8 @@ import (
 	_ "v2ray.com/core/transport/internet/udp"
 	_ "v2ray.com/core/transport/internet/ws"
 
-	_ "v2ray.com/core/transport/internet/authenticators/http"
-	_ "v2ray.com/core/transport/internet/authenticators/noop"
-	_ "v2ray.com/core/transport/internet/authenticators/srtp"
-	_ "v2ray.com/core/transport/internet/authenticators/utp"
+	_ "v2ray.com/core/transport/internet/headers/http"
+	_ "v2ray.com/core/transport/internet/headers/noop"
+	_ "v2ray.com/core/transport/internet/headers/srtp"
+	_ "v2ray.com/core/transport/internet/headers/utp"
 )

tools/conf/transport_authenticators.go

@@ -3,10 +3,10 @@ package conf
 import (
 	"v2ray.com/core/common/errors"
 	"v2ray.com/core/common/loader"
-	"v2ray.com/core/transport/internet/authenticators/http"
-	"v2ray.com/core/transport/internet/authenticators/noop"
-	"v2ray.com/core/transport/internet/authenticators/srtp"
-	"v2ray.com/core/transport/internet/authenticators/utp"
+	"v2ray.com/core/transport/internet/headers/http"
+	"v2ray.com/core/transport/internet/headers/noop"
+	"v2ray.com/core/transport/internet/headers/srtp"
+	"v2ray.com/core/transport/internet/headers/utp"
 )
 
 type NoOpAuthenticator struct{}

transport/internet/authenticator_test.go

@@ -1,28 +0,0 @@
-package internet_test
-
-import (
-	"testing"
-
-	"v2ray.com/core/common/loader"
-	"v2ray.com/core/testing/assert"
-	. "v2ray.com/core/transport/internet"
-	"v2ray.com/core/transport/internet/authenticators/noop"
-	"v2ray.com/core/transport/internet/authenticators/srtp"
-	"v2ray.com/core/transport/internet/authenticators/utp"
-)
-
-func TestAllAuthenticatorLoadable(t *testing.T) {
-	assert := assert.On(t)
-
-	noopAuth, err := CreateAuthenticator(loader.GetType(new(noop.Config)), nil)
-	assert.Error(err).IsNil()
-	assert.Int(noopAuth.Overhead()).Equals(0)
-
-	srtp, err := CreateAuthenticator(loader.GetType(new(srtp.Config)), nil)
-	assert.Error(err).IsNil()
-	assert.Int(srtp.Overhead()).Equals(4)
-
-	utp, err := CreateAuthenticator(loader.GetType(new(utp.Config)), nil)
-	assert.Error(err).IsNil()
-	assert.Int(utp.Overhead()).Equals(4)
-}

transport/internet/authenticators/noop/config.proto

@@ -1,8 +0,0 @@
-syntax = "proto3";
-
-package v2ray.core.transport.internet.authenticators.noop;
-option go_package = "noop";
-option java_package = "com.v2ray.core.transport.internet.authenticators.noop";
-option java_outer_classname = "ConfigProto";
-
-message Config {}

transport/internet/authenticators/noop/noop.go

@@ -1,46 +0,0 @@
-package noop
-
-import (
-	"net"
-
-	"v2ray.com/core/common/alloc"
-	"v2ray.com/core/common/loader"
-	"v2ray.com/core/transport/internet"
-)
-
-type NoOpAuthenticator struct{}
-
-func (v NoOpAuthenticator) Overhead() int {
-	return 0
-}
-func (v NoOpAuthenticator) Open(payload *alloc.Buffer) bool {
-	return true
-}
-func (v NoOpAuthenticator) Seal(payload *alloc.Buffer) {}
-
-type NoOpAuthenticatorFactory struct{}
-
-func (v NoOpAuthenticatorFactory) Create(config interface{}) internet.Authenticator {
-	return NoOpAuthenticator{}
-}
-
-type NoOpConnectionAuthenticator struct{}
-
-func (NoOpConnectionAuthenticator) Client(conn net.Conn) net.Conn {
-	return conn
-}
-
-func (NoOpConnectionAuthenticator) Server(conn net.Conn) net.Conn {
-	return conn
-}
-
-type NoOpConnectionAuthenticatorFactory struct{}
-
-func (NoOpConnectionAuthenticatorFactory) Create(config interface{}) internet.ConnectionAuthenticator {
-	return NoOpConnectionAuthenticator{}
-}
-
-func init() {
-	internet.RegisterAuthenticator(loader.GetType(new(Config)), NoOpAuthenticatorFactory{})
-	internet.RegisterConnectionAuthenticator(loader.GetType(new(Config)), NoOpConnectionAuthenticatorFactory{})
-}

transport/internet/authenticators/srtp/srtp.go

@@ -1,44 +0,0 @@
-package srtp
-
-import (
-	"math/rand"
-
-	"v2ray.com/core/common/alloc"
-	"v2ray.com/core/common/loader"
-	"v2ray.com/core/common/serial"
-	"v2ray.com/core/transport/internet"
-)
-
-type SRTP struct {
-	header uint16
-	number uint16
-}
-
-func (v *SRTP) Overhead() int {
-	return 4
-}
-
-func (v *SRTP) Open(payload *alloc.Buffer) bool {
-	payload.SliceFrom(v.Overhead())
-	return true
-}
-
-func (v *SRTP) Seal(payload *alloc.Buffer) {
-	v.number++
-	payload.PrependFunc(2, serial.WriteUint16(v.number))
-	payload.PrependFunc(2, serial.WriteUint16(v.header))
-}
-
-type SRTPFactory struct {
-}
-
-func (v SRTPFactory) Create(rawSettings interface{}) internet.Authenticator {
-	return &SRTP{
-		header: 0xB5E8,
-		number: uint16(rand.Intn(65536)),
-	}
-}
-
-func init() {
-	internet.RegisterAuthenticator(loader.GetType(new(Config)), SRTPFactory{})
-}

transport/internet/authenticators/utp/config.proto

@@ -1,10 +0,0 @@
-syntax = "proto3";
-
-package v2ray.core.transport.internet.authenticators.utp;
-option go_package = "utp";
-option java_package = "com.v2ray.core.transport.internet.authenticators.utp";
-option java_outer_classname = "ConfigProto";
-
-message Config {
-  uint32 version = 1;
-}

transport/internet/authenticators/utp/utp.go

@@ -1,44 +0,0 @@
-package utp
-
-import (
-	"math/rand"
-
-	"v2ray.com/core/common/alloc"
-	"v2ray.com/core/common/loader"
-	"v2ray.com/core/common/serial"
-	"v2ray.com/core/transport/internet"
-)
-
-type UTP struct {
-	header       byte
-	extension    byte
-	connectionId uint16
-}
-
-func (v *UTP) Overhead() int {
-	return 4
-}
-
-func (v *UTP) Open(payload *alloc.Buffer) bool {
-	payload.SliceFrom(v.Overhead())
-	return true
-}
-
-func (v *UTP) Seal(payload *alloc.Buffer) {
-	payload.PrependFunc(2, serial.WriteUint16(v.connectionId))
-	payload.PrependBytes(v.header, v.extension)
-}
-
-type UTPFactory struct{}
-
-func (v UTPFactory) Create(rawSettings interface{}) internet.Authenticator {
-	return &UTP{
-		header:       1,
-		extension:    0,
-		connectionId: uint16(rand.Intn(65536)),
-	}
-}
-
-func init() {
-	internet.RegisterAuthenticator(loader.GetType(new(Config)), UTPFactory{})
-}

transport/internet/dialer_test.go

@@ -9,20 +9,6 @@ import (
 	. "v2ray.com/core/transport/internet"
 )
 
-func TestDialDomain(t *testing.T) {
-	assert := assert.On(t)
-
-	server := &tcp.Server{}
-	dest, err := server.Start()
-	assert.Error(err).IsNil()
-	defer server.Close()
-
-	conn, err := DialToDest(nil, v2net.TCPDestination(v2net.DomainAddress("local.v2ray.com"), dest.Port))
-	assert.Error(err).IsNil()
-	assert.String(conn.RemoteAddr().String()).Equals("127.0.0.1:" + dest.Port.String())
-	conn.Close()
-}
-
 func TestDialWithLocalAddr(t *testing.T) {
 	assert := assert.On(t)
 

transport/internet/header.go

@@ -0,0 +1,32 @@
+package internet
+
+import "v2ray.com/core/common"
+
+type PacketHeader interface {
+	Size() int
+	Write([]byte) int
+}
+
+type PacketHeaderFactory interface {
+	Create(interface{}) PacketHeader
+}
+
+var (
+	headerCache = make(map[string]PacketHeaderFactory)
+)
+
+func RegisterPacketHeader(name string, factory PacketHeaderFactory) error {
+	if _, found := headerCache[name]; found {
+		return common.ErrDuplicatedName
+	}
+	headerCache[name] = factory
+	return nil
+}
+
+func CreatePacketHeader(name string, config interface{}) (PacketHeader, error) {
+	factory, found := headerCache[name]
+	if !found {
+		return nil, common.ErrObjectNotFound
+	}
+	return factory.Create(config), nil
+}

transport/internet/header_test.go

@@ -0,0 +1,28 @@
+package internet_test
+
+import (
+	"testing"
+
+	"v2ray.com/core/common/loader"
+	"v2ray.com/core/testing/assert"
+	. "v2ray.com/core/transport/internet"
+	"v2ray.com/core/transport/internet/headers/noop"
+	"v2ray.com/core/transport/internet/headers/srtp"
+	"v2ray.com/core/transport/internet/headers/utp"
+)
+
+func TestAllHeadersLoadable(t *testing.T) {
+	assert := assert.On(t)
+
+	noopAuth, err := CreatePacketHeader(loader.GetType(new(noop.Config)), nil)
+	assert.Error(err).IsNil()
+	assert.Int(noopAuth.Size()).Equals(0)
+
+	srtp, err := CreatePacketHeader(loader.GetType(new(srtp.Config)), nil)
+	assert.Error(err).IsNil()
+	assert.Int(srtp.Size()).Equals(4)
+
+	utp, err := CreatePacketHeader(loader.GetType(new(utp.Config)), nil)
+	assert.Error(err).IsNil()
+	assert.Int(utp.Size()).Equals(4)
+}

transport/internet/authenticators/http/config.proto → transport/internet/headers/http/config.proto

@@ -1,8 +1,8 @@
 syntax = "proto3";
 
-package v2ray.core.transport.internet.authenticators.http;
+package v2ray.core.transport.internet.headers.http;
 option go_package = "http";
-option java_package = "com.v2ray.core.transport.internet.authenticators.http";
+option java_package = "com.v2ray.core.transport.internet.headers.http";
 option java_outer_classname = "ConfigProto";
 
 message Header {

transport/internet/authenticators/http/http_test.go → transport/internet/headers/http/http_test.go

@@ -6,7 +6,7 @@ import (
 	"v2ray.com/core/common/alloc"
 	"v2ray.com/core/common/serial"
 	"v2ray.com/core/testing/assert"
-	. "v2ray.com/core/transport/internet/authenticators/http"
+	. "v2ray.com/core/transport/internet/headers/http"
 )
 
 func TestReaderWriter(t *testing.T) {

transport/internet/headers/noop/config.proto

@@ -0,0 +1,8 @@
+syntax = "proto3";
+
+package v2ray.core.transport.internet.headers.noop;
+option go_package = "noop";
+option java_package = "com.v2ray.core.transport.internet.headers.noop";
+option java_outer_classname = "ConfigProto";
+
+message Config {}

transport/internet/headers/noop/noop.go

@@ -0,0 +1,44 @@
+package noop
+
+import (
+	"net"
+
+	"v2ray.com/core/common/loader"
+	"v2ray.com/core/transport/internet"
+)
+
+type NoOpHeader struct{}
+
+func (v NoOpHeader) Size() int {
+	return 0
+}
+func (v NoOpHeader) Write([]byte) int {
+	return 0
+}
+
+type NoOpHeaderFactory struct{}
+
+func (v NoOpHeaderFactory) Create(config interface{}) internet.PacketHeader {
+	return NoOpHeader{}
+}
+
+type NoOpConnectionHeader struct{}
+
+func (NoOpConnectionHeader) Client(conn net.Conn) net.Conn {
+	return conn
+}
+
+func (NoOpConnectionHeader) Server(conn net.Conn) net.Conn {
+	return conn
+}
+
+type NoOpConnectionHeaderFactory struct{}
+
+func (NoOpConnectionHeaderFactory) Create(config interface{}) internet.ConnectionAuthenticator {
+	return NoOpConnectionHeader{}
+}
+
+func init() {
+	internet.RegisterPacketHeader(loader.GetType(new(Config)), NoOpHeaderFactory{})
+	internet.RegisterConnectionAuthenticator(loader.GetType(new(Config)), NoOpConnectionHeaderFactory{})
+}

transport/internet/authenticators/srtp/config.proto → transport/internet/headers/srtp/config.proto

@@ -1,8 +1,8 @@
 syntax = "proto3";
 
-package v2ray.core.transport.internet.authenticators.srtp;
+package v2ray.core.transport.internet.headers.srtp;
 option go_package = "srtp";
-option java_package = "com.v2ray.core.transport.internet.authenticators.srtp";
+option java_package = "com.v2ray.core.transport.internet.headers.srtp";
 option java_outer_classname = "ConfigProto";
 
 message Config {

transport/internet/headers/srtp/srtp.go

@@ -0,0 +1,39 @@
+package srtp
+
+import (
+	"math/rand"
+
+	"v2ray.com/core/common/loader"
+	"v2ray.com/core/common/serial"
+	"v2ray.com/core/transport/internet"
+)
+
+type SRTP struct {
+	header uint16
+	number uint16
+}
+
+func (v *SRTP) Size() int {
+	return 4
+}
+
+func (v *SRTP) Write(b []byte) int {
+	v.number++
+	b = serial.Uint16ToBytes(v.number, b[:0])
+	b = serial.Uint16ToBytes(v.number, b)
+	return 4
+}
+
+type SRTPFactory struct {
+}
+
+func (v SRTPFactory) Create(rawSettings interface{}) internet.PacketHeader {
+	return &SRTP{
+		header: 0xB5E8,
+		number: uint16(rand.Intn(65536)),
+	}
+}
+
+func init() {
+	internet.RegisterPacketHeader(loader.GetType(new(Config)), SRTPFactory{})
+}

transport/internet/authenticators/srtp/srtp_test.go → transport/internet/headers/srtp/srtp_test.go

@@ -5,19 +5,18 @@ import (
 
 	"v2ray.com/core/common/alloc"
 	"v2ray.com/core/testing/assert"
-	. "v2ray.com/core/transport/internet/authenticators/srtp"
+	. "v2ray.com/core/transport/internet/headers/srtp"
 )
 
-func TestSRTPOpenSeal(t *testing.T) {
+func TestSRTPWrite(t *testing.T) {
 	assert := assert.On(t)
 
 	content := []byte{'a', 'b', 'c', 'd', 'e', 'f', 'g'}
+	srtp := SRTP{}
+
 	payload := alloc.NewLocalBuffer(2048)
+	payload.AppendFunc(srtp.Write)
 	payload.Append(content)
 
-	srtp := SRTP{}
-	srtp.Seal(payload)
-	assert.Int(payload.Len()).GreaterThan(len(content))
-	assert.Bool(srtp.Open(payload)).IsTrue()
-	assert.Bytes(content).Equals(payload.Bytes())
+	assert.Int(payload.Len()).Equals(len(content) + srtp.Size())
 }

transport/internet/headers/utp/config.proto

@@ -0,0 +1,10 @@
+syntax = "proto3";
+
+package v2ray.core.transport.internet.headers.utp;
+option go_package = "utp";
+option java_package = "com.v2ray.core.transport.internet.headers.utp";
+option java_outer_classname = "ConfigProto";
+
+message Config {
+  uint32 version = 1;
+}

transport/internet/headers/utp/utp.go

@@ -0,0 +1,39 @@
+package utp
+
+import (
+	"math/rand"
+
+	"v2ray.com/core/common/loader"
+	"v2ray.com/core/common/serial"
+	"v2ray.com/core/transport/internet"
+)
+
+type UTP struct {
+	header       byte
+	extension    byte
+	connectionId uint16
+}
+
+func (v *UTP) Size() int {
+	return 4
+}
+
+func (v *UTP) Write(b []byte) int {
+	b = serial.Uint16ToBytes(v.connectionId, b[:0])
+	b = append(b, v.header, v.extension)
+	return 4
+}
+
+type UTPFactory struct{}
+
+func (v UTPFactory) Create(rawSettings interface{}) internet.PacketHeader {
+	return &UTP{
+		header:       1,
+		extension:    0,
+		connectionId: uint16(rand.Intn(65536)),
+	}
+}
+
+func init() {
+	internet.RegisterPacketHeader(loader.GetType(new(Config)), UTPFactory{})
+}

transport/internet/authenticators/utp/utp_test.go → transport/internet/headers/utp/utp_test.go

@@ -5,19 +5,18 @@ import (
 
 	"v2ray.com/core/common/alloc"
 	"v2ray.com/core/testing/assert"
-	. "v2ray.com/core/transport/internet/authenticators/utp"
+	. "v2ray.com/core/transport/internet/headers/utp"
 )
 
-func TestUTPOpenSeal(t *testing.T) {
+func TestUTPWrite(t *testing.T) {
 	assert := assert.On(t)
 
 	content := []byte{'a', 'b', 'c', 'd', 'e', 'f', 'g'}
+	utp := UTP{}
+
 	payload := alloc.NewLocalBuffer(2048)
+	payload.AppendFunc(utp.Write)
 	payload.Append(content)
 
-	utp := UTP{}
-	utp.Seal(payload)
-	assert.Int(payload.Len()).GreaterThan(len(content))
-	assert.Bool(utp.Open(payload)).IsTrue()
-	assert.Bytes(content).Equals(payload.Bytes())
+	assert.Int(payload.Len()).Equals(len(content) + utp.Size())
 }

transport/internet/kcp/config.go

@@ -1,6 +1,8 @@
 package kcp
 
 import (
+	"crypto/cipher"
+
 	v2net "v2ray.com/core/common/net"
 	"v2ray.com/core/transport/internet"
 )
@@ -47,21 +49,20 @@ func (v *ReadBuffer) GetSize() uint32 {
 	return v.Size
 }
 
-func (v *Config) GetAuthenticator() (internet.Authenticator, error) {
-	auth := NewSimpleAuthenticator()
+func (v *Config) GetSecurity() (cipher.AEAD, error) {
+	return NewSimpleAuthenticator(), nil
+}
+
+func (v *Config) GetPackerHeader() (internet.PacketHeader, error) {
 	if v.HeaderConfig != nil {
 		rawConfig, err := v.HeaderConfig.GetInstance()
 		if err != nil {
 			return nil, err
 		}
 
-		header, err := internet.CreateAuthenticator(v.HeaderConfig.Type, rawConfig)
-		if err != nil {
-			return nil, err
-		}
-		auth = internet.NewAuthenticatorChain(header, auth)
+		return internet.CreatePacketHeader(v.HeaderConfig.Type, rawConfig)
 	}
-	return auth, nil
+	return nil, nil
 }
 
 func (v *Config) GetSendingInFlightSize() uint32 {

transport/internet/kcp/connection.go

@@ -6,6 +6,7 @@ import (
 	"sync"
 	"sync/atomic"
 	"time"
+
 	"v2ray.com/core/common/errors"
 	"v2ray.com/core/common/log"
 	"v2ray.com/core/common/predicate"
@@ -161,7 +162,8 @@ func (v *Updater) Run() {
 type SystemConnection interface {
 	net.Conn
 	Id() internal.ConnectionId
-	Reset(internet.Authenticator, func([]byte))
+	Reset(func([]Segment))
+	Overhead() int
 }
 
 // Connection is a KCP connection over UDP.
@@ -197,32 +199,25 @@ type Connection struct {
 }
 
 // NewConnection create a new KCP connection between local and remote.
-func NewConnection(conv uint16, sysConn SystemConnection, recycler internal.ConnectionRecyler, block internet.Authenticator, config *Config) *Connection {
+func NewConnection(conv uint16, sysConn SystemConnection, recycler internal.ConnectionRecyler, config *Config) *Connection {
 	log.Info("KCP|Connection: creating connection ", conv)
 
-	authWriter := &AuthenticationWriter{
-		Authenticator: block,
-		Writer:        sysConn,
-		Config:        config,
-	}
-
 	conn := &Connection{
 		conv:           conv,
 		conn:           sysConn,
 		connRecycler:   recycler,
-		block:          block,
 		since:          nowMillisec(),
 		dataInputCond:  sync.NewCond(new(sync.Mutex)),
 		dataOutputCond: sync.NewCond(new(sync.Mutex)),
 		Config:         config,
-		output:         NewSegmentWriter(authWriter),
-		mss:            authWriter.Mtu() - DataSegmentOverhead,
+		output:         NewSegmentWriter(sysConn, config.GetMtu().GetValue()-uint32(sysConn.Overhead())),
+		mss:            config.GetMtu().GetValue() - uint32(sysConn.Overhead()) - DataSegmentOverhead,
 		roundTrip: &RoundTripInfo{
 			rto:    100,
 			minRtt: config.Tti.GetValue(),
 		},
 	}
-	sysConn.Reset(block, conn.Input)
+	sysConn.Reset(conn.Input)
 
 	conn.receivingWorker = NewReceivingWorker(conn)
 	conn.sendingWorker = NewSendingWorker(conn)
@@ -480,16 +475,11 @@ func (v *Connection) OnPeerClosed() {
 }
 
 // Input when you received a low level packet (eg. UDP packet), call it
-func (v *Connection) Input(data []byte) {
+func (v *Connection) Input(segments []Segment) {
 	current := v.Elapsed()
 	atomic.StoreUint32(&v.lastIncomingTime, current)
 
-	var seg Segment
-	for {
-		seg, data = ReadSegment(data)
-		if seg == nil {
-			break
-		}
+	for _, seg := range segments {
 		if seg.Conversation() != v.conv {
 			return
 		}
@@ -507,7 +497,7 @@ func (v *Connection) Input(data []byte) {
 			v.dataUpdater.WakeUp()
 		case *CmdOnlySegment:
 			v.HandleOption(seg.Option)
-			if seg.Command == CommandTerminate {
+			if seg.Command() == CommandTerminate {
 				state := v.State()
 				if state == StateActive ||
 					state == StatePeerClosed {
@@ -577,7 +567,7 @@ func (v *Connection) State() State {
 func (v *Connection) Ping(current uint32, cmd Command) {
 	seg := NewCmdOnlySegment()
 	seg.Conv = v.conv
-	seg.Command = cmd
+	seg.Cmd = cmd
 	seg.ReceivinNext = v.receivingWorker.nextNumber
 	seg.SendingNext = v.sendingWorker.firstUnacknowledged
 	seg.PeerRTO = v.roundTrip.Timeout()

transport/internet/kcp/connection_test.go

@@ -4,14 +4,18 @@ import (
 	"net"
 	"testing"
 	"time"
+
 	"v2ray.com/core/testing/assert"
-	"v2ray.com/core/transport/internet"
 	"v2ray.com/core/transport/internet/internal"
 	. "v2ray.com/core/transport/internet/kcp"
 )
 
 type NoOpConn struct{}
 
+func (o *NoOpConn) Overhead() int {
+	return 0
+}
+
 func (o *NoOpConn) Write(b []byte) (int, error) {
 	return len(b), nil
 }
@@ -48,7 +52,7 @@ func (o *NoOpConn) Id() internal.ConnectionId {
 	return internal.ConnectionId{}
 }
 
-func (o *NoOpConn) Reset(auth internet.Authenticator, input func([]byte)) {}
+func (o *NoOpConn) Reset(input func([]Segment)) {}
 
 type NoOpRecycler struct{}
 
@@ -57,7 +61,7 @@ func (o *NoOpRecycler) Put(internal.ConnectionId, net.Conn) {}
 func TestConnectionReadTimeout(t *testing.T) {
 	assert := assert.On(t)
 
-	conn := NewConnection(1, &NoOpConn{}, &NoOpRecycler{}, NewSimpleAuthenticator(), &Config{})
+	conn := NewConnection(1, &NoOpConn{}, &NoOpRecycler{}, &Config{})
 	conn.SetReadDeadline(time.Now().Add(time.Second))
 
 	b := make([]byte, 1024)

transport/internet/kcp/crypt.go

@@ -1,63 +1,74 @@
 package kcp
 
 import (
+	"crypto/cipher"
+	"errors"
 	"hash/fnv"
 
-	"v2ray.com/core/common/alloc"
 	"v2ray.com/core/common/serial"
-	"v2ray.com/core/transport/internet"
+)
+
+var (
+	errInvalidAuth = errors.New("Invalid auth.")
 )
 
 type SimpleAuthenticator struct{}
 
-func NewSimpleAuthenticator() internet.Authenticator {
+func NewSimpleAuthenticator() cipher.AEAD {
 	return &SimpleAuthenticator{}
 }
 
+func (v *SimpleAuthenticator) NonceSize() int {
+	return 0
+}
+
 func (v *SimpleAuthenticator) Overhead() int {
 	return 6
 }
 
-func (v *SimpleAuthenticator) Seal(buffer *alloc.Buffer) {
-	buffer.PrependFunc(2, serial.WriteUint16(uint16(buffer.Len())))
+func (v *SimpleAuthenticator) Seal(dst, nonce, plain, extra []byte) []byte {
+	dst = append(dst, 0, 0, 0, 0)
+	dst = serial.Uint16ToBytes(uint16(len(plain)), dst)
+	dst = append(dst, plain...)
+
 	fnvHash := fnv.New32a()
-	fnvHash.Write(buffer.Bytes())
-	buffer.PrependFunc(4, serial.WriteHash(fnvHash))
+	fnvHash.Write(dst[4:])
+	fnvHash.Sum(dst[:0])
 
-	len := buffer.Len()
+	len := len(dst)
 	xtra := 4 - len%4
-	if xtra != 0 {
-		buffer.Slice(0, len+xtra)
+	if xtra != 4 {
+		dst = append(dst, make([]byte, xtra)...)
 	}
-	xorfwd(buffer.Bytes())
-	if xtra != 0 {
-		buffer.Slice(0, len)
+	xorfwd(dst)
+	if xtra != 4 {
+		dst = dst[:len]
 	}
+	return dst
 }
 
-func (v *SimpleAuthenticator) Open(buffer *alloc.Buffer) bool {
-	len := buffer.Len()
-	xtra := 4 - len%4
-	if xtra != 0 {
-		buffer.Slice(0, len+xtra)
+func (v *SimpleAuthenticator) Open(dst, nonce, cipherText, extra []byte) ([]byte, error) {
+	dst = append(dst, cipherText...)
+	dstLen := len(dst)
+	xtra := 4 - dstLen%4
+	if xtra != 4 {
+		dst = append(dst, make([]byte, xtra)...)
 	}
-	xorbkd(buffer.Bytes())
-	if xtra != 0 {
-		buffer.Slice(0, len)
+	xorbkd(dst)
+	if xtra != 4 {
+		dst = dst[:dstLen]
 	}
 
 	fnvHash := fnv.New32a()
-	fnvHash.Write(buffer.BytesFrom(4))
-	if serial.BytesToUint32(buffer.BytesTo(4)) != fnvHash.Sum32() {
-		return false
+	fnvHash.Write(dst[4:])
+	if serial.BytesToUint32(dst[:4]) != fnvHash.Sum32() {
+		return nil, errInvalidAuth
 	}
 
-	length := serial.BytesToUint16(buffer.BytesRange(4, 6))
-	if buffer.Len()-6 != int(length) {
-		return false
+	length := serial.BytesToUint16(dst[4:6])
+	if len(dst)-6 != int(length) {
+		return nil, errInvalidAuth
 	}
 
-	buffer.SliceFrom(6)
-
-	return true
+	return dst[6:], nil
 }

transport/internet/kcp/crypt_test.go

@@ -1,10 +1,8 @@
 package kcp_test
 
 import (
-	"crypto/rand"
 	"testing"
 
-	"v2ray.com/core/common/alloc"
 	"v2ray.com/core/testing/assert"
 	. "v2ray.com/core/transport/internet/kcp"
 )
@@ -12,38 +10,27 @@ import (
 func TestSimpleAuthenticator(t *testing.T) {
 	assert := assert.On(t)
 
-	buffer := alloc.NewLocalBuffer(512)
-	buffer.AppendBytes('a', 'b', 'c', 'd', 'e', 'f', 'g')
+	cache := make([]byte, 512)
 
-	auth := NewSimpleAuthenticator()
-	auth.Seal(buffer)
+	payload := []byte{'a', 'b', 'c', 'd', 'e', 'f', 'g'}
 
-	assert.Bool(auth.Open(buffer)).IsTrue()
-	assert.Bytes(buffer.Bytes()).Equals([]byte{'a', 'b', 'c', 'd', 'e', 'f', 'g'})
+	auth := NewSimpleAuthenticator()
+	b := auth.Seal(cache[:0], nil, payload, nil)
+	c, err := auth.Open(cache[:0], nil, b, nil)
+	assert.Error(err).IsNil()
+	assert.Bytes(c).Equals(payload)
 }
 
 func TestSimpleAuthenticator2(t *testing.T) {
 	assert := assert.On(t)
 
-	buffer := alloc.NewLocalBuffer(512)
-	buffer.AppendBytes('1', '2')
-
-	auth := NewSimpleAuthenticator()
-	auth.Seal(buffer)
-
-	assert.Bool(auth.Open(buffer)).IsTrue()
-	assert.Bytes(buffer.Bytes()).Equals([]byte{'1', '2'})
-}
+	cache := make([]byte, 512)
 
-func BenchmarkSimpleAuthenticator(b *testing.B) {
-	buffer := alloc.NewLocalBuffer(2048)
-	buffer.FillFullFrom(rand.Reader, 1024)
+	payload := []byte{'a', 'b'}
 
 	auth := NewSimpleAuthenticator()
-	b.SetBytes(int64(buffer.Len()))
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
-		auth.Seal(buffer)
-		auth.Open(buffer)
-	}
+	b := auth.Seal(cache[:0], nil, payload, nil)
+	c, err := auth.Open(cache[:0], nil, b, nil)
+	assert.Error(err).IsNil()
+	assert.Bytes(c).Equals(payload)
 }

transport/internet/kcp/dialer.go

@@ -5,8 +5,12 @@ import (
 	"net"
 	"sync"
 	"sync/atomic"
+
+	"crypto/cipher"
+
 	"v2ray.com/core/common/alloc"
 	"v2ray.com/core/common/dice"
+	"v2ray.com/core/common/errors"
 	"v2ray.com/core/common/log"
 	v2net "v2ray.com/core/common/net"
 	"v2ray.com/core/transport/internet"
@@ -20,11 +24,32 @@ var (
 )
 
 type ClientConnection struct {
-	sync.Mutex
+	sync.RWMutex
 	net.Conn
-	id    internal.ConnectionId
-	input func([]byte)
-	auth  internet.Authenticator
+	id     internal.ConnectionId
+	input  func([]Segment)
+	reader PacketReader
+	writer PacketWriter
+}
+
+func (o *ClientConnection) Overhead() int {
+	o.RLock()
+	defer o.RUnlock()
+	if o.writer == nil {
+		return 0
+	}
+	return o.writer.Overhead()
+}
+
+func (o *ClientConnection) Write(b []byte) (int, error) {
+	o.RLock()
+	defer o.RUnlock()
+
+	if o.writer == nil {
+		return len(b), nil
+	}
+
+	return o.writer.Write(b)
 }
 
 func (o *ClientConnection) Read([]byte) (int, error) {
@@ -39,10 +64,26 @@ func (o *ClientConnection) Close() error {
 	return o.Conn.Close()
 }
 
-func (o *ClientConnection) Reset(auth internet.Authenticator, inputCallback func([]byte)) {
+func (o *ClientConnection) Reset(inputCallback func([]Segment)) {
 	o.Lock()
 	o.input = inputCallback
-	o.auth = auth
+	o.Unlock()
+}
+
+func (o *ClientConnection) ResetSecurity(header internet.PacketHeader, security cipher.AEAD) {
+	o.Lock()
+	if o.reader == nil {
+		o.reader = new(KCPPacketReader)
+	}
+	o.reader.(*KCPPacketReader).Header = header
+	o.reader.(*KCPPacketReader).Security = security
+	if o.writer == nil {
+		o.writer = new(KCPPacketWriter)
+	}
+	o.writer.(*KCPPacketWriter).Header = header
+	o.writer.(*KCPPacketWriter).Security = security
+	o.writer.(*KCPPacketWriter).Writer = o.Conn
+
 	o.Unlock()
 }
 
@@ -57,12 +98,14 @@ func (o *ClientConnection) Run() {
 			payload.Release()
 			return
 		}
-		o.Lock()
-		if o.input != nil && o.auth.Open(payload) {
-			o.input(payload.Bytes())
+		o.RLock()
+		if o.input != nil {
+			segments := o.reader.Read(payload.Bytes())
+			if len(segments) > 0 {
+				o.input(segments)
+			}
 		}
-		o.Unlock()
-		payload.Reset()
+		o.RUnlock()
 	}
 }
 
@@ -93,13 +136,18 @@ func DialKCP(src v2net.Address, dest v2net.Destination, options internet.DialerO
 	}
 	kcpSettings := networkSettings.(*Config)
 
-	cpip, err := kcpSettings.GetAuthenticator()
+	clientConn := conn.(*ClientConnection)
+	header, err := kcpSettings.GetPackerHeader()
 	if err != nil {
-		log.Error("KCP|Dialer: Failed to create authenticator: ", err)
-		return nil, err
+		return nil, errors.Base(err).Message("KCP|Dialer: Failed to create packet header.")
+	}
+	security, err := kcpSettings.GetSecurity()
+	if err != nil {
+		return nil, errors.Base(err).Message("KCP|Dialer: Failed to create security.")
 	}
+	clientConn.ResetSecurity(header, security)
 	conv := uint16(atomic.AddUint32(&globalConv, 1))
-	session := NewConnection(conv, conn.(*ClientConnection), globalPool, cpip, kcpSettings)
+	session := NewConnection(conv, clientConn, globalPool, kcpSettings)
 
 	var iConn internet.Connection
 	iConn = session

transport/internet/kcp/io.go

@@ -0,0 +1,92 @@
+package kcp
+
+import (
+	"crypto/cipher"
+	"crypto/rand"
+	"io"
+
+	"v2ray.com/core/transport/internet"
+)
+
+type PacketReader interface {
+	Read([]byte) []Segment
+}
+
+type PacketWriter interface {
+	Overhead() int
+	io.Writer
+}
+
+type KCPPacketReader struct {
+	Security cipher.AEAD
+	Header   internet.PacketHeader
+}
+
+func (v *KCPPacketReader) Read(b []byte) []Segment {
+	if v.Header != nil {
+		b = b[v.Header.Size():]
+	}
+	if v.Security != nil {
+		nonceSize := v.Security.NonceSize()
+		out, err := v.Security.Open(b[nonceSize:nonceSize], b[:nonceSize], b[nonceSize:], nil)
+		if err != nil {
+			return nil
+		}
+		b = out
+	}
+	var result []Segment
+	for len(b) > 0 {
+		seg, x := ReadSegment(b)
+		if seg == nil {
+			break
+		}
+		result = append(result, seg)
+		b = x
+	}
+	return result
+}
+
+type KCPPacketWriter struct {
+	Header   internet.PacketHeader
+	Security cipher.AEAD
+	Writer   io.Writer
+
+	buffer [32 * 1024]byte
+}
+
+func (v *KCPPacketWriter) Overhead() int {
+	overhead := 0
+	if v.Header != nil {
+		overhead += v.Header.Size()
+	}
+	if v.Security != nil {
+		overhead += v.Security.Overhead()
+	}
+	return overhead
+}
+
+func (v *KCPPacketWriter) Write(b []byte) (int, error) {
+	x := v.buffer[:]
+	size := 0
+	if v.Header != nil {
+		nBytes := v.Header.Write(x)
+		size += nBytes
+		x = x[nBytes:]
+	}
+	if v.Security != nil {
+		nonceSize := v.Security.NonceSize()
+		var nonce []byte
+		if nonceSize > 0 {
+			nonce = x[:nonceSize]
+			rand.Read(nonce)
+			x = x[nonceSize:]
+		}
+		x = v.Security.Seal(x[:0], nonce, b, nil)
+		size += nonceSize + len(x)
+	} else {
+		size += copy(x, b)
+	}
+
+	_, err := v.Writer.Write(v.buffer[:size])
+	return len(b), err
+}

transport/internet/kcp/io_test.go

@@ -0,0 +1 @@
+package kcp_test

transport/internet/kcp/listener.go

@@ -2,14 +2,17 @@ package kcp
 
 import (
 	"crypto/tls"
+	"io"
 	"net"
 	"sync"
 	"time"
 
+	"crypto/cipher"
+
 	"v2ray.com/core/common/alloc"
+	"v2ray.com/core/common/errors"
 	"v2ray.com/core/common/log"
 	v2net "v2ray.com/core/common/net"
-	"v2ray.com/core/common/serial"
 	"v2ray.com/core/proxy"
 	"v2ray.com/core/transport/internet"
 	"v2ray.com/core/transport/internet/internal"
@@ -25,11 +28,14 @@ type ConnectionId struct {
 
 type ServerConnection struct {
 	id     internal.ConnectionId
-	writer *Writer
 	local  net.Addr
 	remote net.Addr
-	auth   internet.Authenticator
-	input  func([]byte)
+	writer PacketWriter
+	closer io.Closer
+}
+
+func (o *ServerConnection) Overhead() int {
+	return o.writer.Overhead()
 }
 
 func (o *ServerConnection) Read([]byte) (int, error) {
@@ -41,20 +47,10 @@ func (o *ServerConnection) Write(b []byte) (int, error) {
 }
 
 func (o *ServerConnection) Close() error {
-	return o.writer.Close()
+	return o.closer.Close()
 }
 
-func (o *ServerConnection) Reset(auth internet.Authenticator, input func([]byte)) {
-	o.auth = auth
-	o.input = input
-}
-
-func (o *ServerConnection) Input(b *alloc.Buffer) {
-	defer b.Release()
-
-	if o.auth.Open(b) {
-		o.input(b.Bytes())
-	}
+func (o *ServerConnection) Reset(input func([]Segment)) {
 }
 
 func (o *ServerConnection) LocalAddr() net.Addr {
@@ -85,12 +81,14 @@ func (o *ServerConnection) Id() internal.ConnectionId {
 type Listener struct {
 	sync.Mutex
 	running       bool
-	authenticator internet.Authenticator
 	sessions      map[ConnectionId]*Connection
 	awaitingConns chan *Connection
 	hub           *udp.UDPHub
 	tlsConfig     *tls.Config
 	config        *Config
+	reader        PacketReader
+	header        internet.PacketHeader
+	security      cipher.AEAD
 }
 
 func NewListener(address v2net.Address, port v2net.Port, options internet.ListenOptions) (*Listener, error) {
@@ -102,12 +100,21 @@ func NewListener(address v2net.Address, port v2net.Port, options internet.Listen
 	kcpSettings := networkSettings.(*Config)
 	kcpSettings.ConnectionReuse = &ConnectionReuse{Enable: false}
 
-	auth, err := kcpSettings.GetAuthenticator()
+	header, err := kcpSettings.GetPackerHeader()
 	if err != nil {
-		return nil, err
+		return nil, errors.Base(err).Message("KCP|Listener: Failed to create packet header.")
+	}
+	security, err := kcpSettings.GetSecurity()
+	if err != nil {
+		return nil, errors.Base(err).Message("KCP|Listener: Failed to create security.")
 	}
 	l := &Listener{
-		authenticator: auth,
+		header:   header,
+		security: security,
+		reader: &KCPPacketReader{
+			Header:   header,
+			Security: security,
+		},
 		sessions:      make(map[ConnectionId]*Connection),
 		awaitingConns: make(chan *Connection, 64),
 		running:       true,
@@ -138,10 +145,12 @@ func (v *Listener) OnReceive(payload *alloc.Buffer, session *proxy.SessionInfo)
 
 	src := session.Source
 
-	if valid := v.authenticator.Open(payload); !valid {
+	segments := v.reader.Read(payload.Bytes())
+	if len(segments) == 0 {
 		log.Info("KCP|Listener: discarding invalid payload from ", src)
 		return
 	}
+
 	if !v.running {
 		return
 	}
@@ -153,8 +162,9 @@ func (v *Listener) OnReceive(payload *alloc.Buffer, session *proxy.SessionInfo)
 	if payload.Len() < 4 {
 		return
 	}
-	conv := serial.BytesToUint16(payload.BytesTo(2))
-	cmd := Command(payload.Byte(2))
+	conv := segments[0].Conversation()
+	cmd := segments[0].Command()
+
 	id := ConnectionId{
 		Remote: src.Address,
 		Port:   src.Port,
@@ -177,17 +187,18 @@ func (v *Listener) OnReceive(payload *alloc.Buffer, session *proxy.SessionInfo)
 			Port: int(src.Port),
 		}
 		localAddr := v.hub.Addr()
-		auth, err := v.config.GetAuthenticator()
-		if err != nil {
-			log.Error("KCP|Listener: Failed to create authenticator: ", err)
-		}
 		sConn := &ServerConnection{
 			id:     internal.NewConnectionId(v2net.LocalHostIP, src),
 			local:  localAddr,
 			remote: remoteAddr,
-			writer: writer,
+			writer: &KCPPacketWriter{
+				Header:   v.header,
+				Writer:   writer,
+				Security: v.security,
+			},
+			closer: writer,
 		}
-		conn = NewConnection(conv, sConn, v, auth, v.config)
+		conn = NewConnection(conv, sConn, v, v.config)
 		select {
 		case v.awaitingConns <- conn:
 		case <-time.After(time.Second * 5):
@@ -196,7 +207,7 @@ func (v *Listener) OnReceive(payload *alloc.Buffer, session *proxy.SessionInfo)
 		}
 		v.sessions[id] = conn
 	}
-	conn.Input(payload.Bytes())
+	conn.Input(segments)
 }
 
 func (v *Listener) Remove(id ConnectionId) {

transport/internet/kcp/output.go

@@ -5,8 +5,6 @@ import (
 	"sync"
 
 	"v2ray.com/core/common/alloc"
-	v2io "v2ray.com/core/common/io"
-	"v2ray.com/core/transport/internet"
 )
 
 type SegmentWriter interface {
@@ -17,13 +15,14 @@ type BufferedSegmentWriter struct {
 	sync.Mutex
 	mtu    uint32
 	buffer *alloc.Buffer
-	writer v2io.Writer
+	writer io.Writer
 }
 
-func NewSegmentWriter(writer *AuthenticationWriter) *BufferedSegmentWriter {
+func NewSegmentWriter(writer io.Writer, mtu uint32) *BufferedSegmentWriter {
 	return &BufferedSegmentWriter{
-		mtu:    writer.Mtu(),
+		mtu:    mtu,
 		writer: writer,
+		buffer: alloc.NewSmallBuffer(),
 	}
 }
 
@@ -36,45 +35,21 @@ func (v *BufferedSegmentWriter) Write(seg Segment) {
 		v.FlushWithoutLock()
 	}
 
-	if v.buffer == nil {
-		v.buffer = alloc.NewSmallBuffer()
-	}
-
 	v.buffer.AppendFunc(seg.Bytes())
 }
 
 func (v *BufferedSegmentWriter) FlushWithoutLock() {
-	v.writer.Write(v.buffer)
-	v.buffer = nil
+	v.writer.Write(v.buffer.Bytes())
+	v.buffer.Clear()
 }
 
 func (v *BufferedSegmentWriter) Flush() {
 	v.Lock()
 	defer v.Unlock()
 
-	if v.buffer.Len() == 0 {
+	if v.buffer.IsEmpty() {
 		return
 	}
 
 	v.FlushWithoutLock()
 }
-
-type AuthenticationWriter struct {
-	Authenticator internet.Authenticator
-	Writer        io.Writer
-	Config        *Config
-}
-
-func (v *AuthenticationWriter) Write(payload *alloc.Buffer) error {
-	defer payload.Release()
-
-	v.Authenticator.Seal(payload)
-	_, err := v.Writer.Write(payload.Bytes())
-	return err
-}
-
-func (v *AuthenticationWriter) Release() {}
-
-func (v *AuthenticationWriter) Mtu() uint32 {
-	return v.Config.Mtu.GetValue() - uint32(v.Authenticator.Overhead())
-}

transport/internet/kcp/segment.go

@@ -24,6 +24,7 @@ const (
 type Segment interface {
 	common.Releasable
 	Conversation() uint16
+	Command() Command
 	ByteSize() int
 	Bytes() alloc.BytesWriter
 }
@@ -52,6 +53,10 @@ func (v *DataSegment) Conversation() uint16 {
 	return v.Conv
 }
 
+func (v *DataSegment) Command() Command {
+	return CommandData
+}
+
 func (v *DataSegment) SetData(b []byte) {
 	if v.Data == nil {
 		v.Data = alloc.NewSmallBuffer()
@@ -104,6 +109,10 @@ func (v *AckSegment) Conversation() uint16 {
 	return v.Conv
 }
 
+func (v *AckSegment) Command() Command {
+	return CommandACK
+}
+
 func (v *AckSegment) PutTimestamp(timestamp uint32) {
 	if timestamp-v.Timestamp < 0x7FFFFFFF {
 		v.Timestamp = timestamp
@@ -144,7 +153,7 @@ func (v *AckSegment) Release() {
 
 type CmdOnlySegment struct {
 	Conv         uint16
-	Command      Command
+	Cmd          Command
 	Option       SegmentOption
 	SendingNext  uint32
 	ReceivinNext uint32
@@ -159,6 +168,10 @@ func (v *CmdOnlySegment) Conversation() uint16 {
 	return v.Conv
 }
 
+func (v *CmdOnlySegment) Command() Command {
+	return v.Cmd
+}
+
 func (v *CmdOnlySegment) ByteSize() int {
 	return 2 + 1 + 1 + 4 + 4 + 4
 }
@@ -166,7 +179,7 @@ func (v *CmdOnlySegment) ByteSize() int {
 func (v *CmdOnlySegment) Bytes() alloc.BytesWriter {
 	return func(b []byte) int {
 		b = serial.Uint16ToBytes(v.Conv, b[:0])
-		b = append(b, byte(v.Command), byte(v.Option))
+		b = append(b, byte(v.Cmd), byte(v.Option))
 		b = serial.Uint32ToBytes(v.SendingNext, b)
 		b = serial.Uint32ToBytes(v.ReceivinNext, b)
 		b = serial.Uint32ToBytes(v.PeerRTO, b)
@@ -250,7 +263,7 @@ func ReadSegment(buf []byte) (Segment, []byte) {
 
 	seg := NewCmdOnlySegment()
 	seg.Conv = conv
-	seg.Command = cmd
+	seg.Cmd = cmd
 	seg.Option = opt
 
 	if len(buf) < 12 {

transport/internet/kcp/segment_test.go

@@ -79,7 +79,7 @@ func TestCmdSegment(t *testing.T) {
 
 	seg := &CmdOnlySegment{
 		Conv:         1,
-		Command:      CommandPing,
+		Cmd:          CommandPing,
 		Option:       SegmentOptionClose,
 		SendingNext:  11,
 		ReceivinNext: 13,
@@ -95,7 +95,7 @@ func TestCmdSegment(t *testing.T) {
 	iseg, _ := ReadSegment(bytes)
 	seg2 := iseg.(*CmdOnlySegment)
 	assert.Uint16(seg2.Conv).Equals(seg.Conv)
-	assert.Byte(byte(seg2.Command)).Equals(byte(seg.Command))
+	assert.Byte(byte(seg2.Command())).Equals(byte(seg.Command()))
 	assert.Byte(byte(seg2.Option)).Equals(byte(seg.Option))
 	assert.Uint32(seg2.SendingNext).Equals(seg.SendingNext)
 	assert.Uint32(seg2.ReceivinNext).Equals(seg.ReceivinNext)