Time based user hash

id.go

@@ -1,27 +1,68 @@
 package core
 
 import (
+	"crypto/hmac"
 	"crypto/md5"
 	"encoding/hex"
+	"hash"
+	mrand "math/rand"
+	"time"
 
 	"github.com/v2ray/v2ray-core/log"
 )
 
-// The ID of en entity, in the form of an UUID.
-type ID [16]byte
+const (
+	IDBytesLen = 16
+)
 
-// Hash generates a MD5 hash based on current ID and a suffix string.
-func (v ID) Hash(suffix []byte) []byte {
-	md5 := md5.New()
-	md5.Write(v[:])
-	md5.Write(suffix)
-	return md5.Sum(nil)
+// The ID of en entity, in the form of an UUID.
+type ID struct {
+	String string
+	Bytes  []byte
+	hasher hash.Hash
+}
+
+func NewID(id string) (ID, error) {
+	idBytes, err := UUIDToID(id)
+	if err != nil {
+		return ID{}, log.Error("Failed to parse id %s", id)
+	}
+	hasher := hmac.New(md5.New, idBytes)
+	return ID{id, idBytes, hasher}, nil
+}
+
+func (v ID) TimeRangeHash(rangeSec int) []byte {
+	nowSec := time.Now().UTC().Unix()
+	delta := mrand.Intn(rangeSec*2) - rangeSec
+
+	targetSec := nowSec + int64(delta)
+	return v.TimeHash(targetSec)
+}
+
+func (v ID) TimeHash(timeSec int64) []byte {
+	buffer := []byte{
+		byte(timeSec >> 56),
+		byte(timeSec >> 48),
+		byte(timeSec >> 40),
+		byte(timeSec >> 32),
+		byte(timeSec >> 24),
+		byte(timeSec >> 16),
+		byte(timeSec >> 8),
+		byte(timeSec),
+	}
+	return v.Hash(buffer)
+}
+
+func (v ID) Hash(data []byte) []byte {
+	return v.hasher.Sum(data)
 }
 
 var byteGroups = []int{8, 4, 4, 4, 12}
 
 // TODO: leverage a full functional UUID library
-func UUIDToID(uuid string) (v ID, err error) {
+func UUIDToID(uuid string) (v []byte, err error) {
+	v = make([]byte, 16)
+
 	text := []byte(uuid)
 	if len(text) < 32 {
 		err = log.Error("uuid: invalid UUID string: %s", text)

id_test.go

@@ -13,5 +13,5 @@ func TestUUIDToID(t *testing.T) {
 	expectedBytes := []byte{0x24, 0x18, 0xd0, 0x87, 0x64, 0x8d, 0x49, 0x90, 0x86, 0xe8, 0x19, 0xdc, 0xa1, 0xd0, 0x06, 0xd3}
 
 	actualBytes, _ := UUIDToID(uuid)
-	assert.Bytes(actualBytes[:]).Named("UUID").Equals(expectedBytes)
+	assert.Bytes(actualBytes.Bytes()).Named("UUID").Equals(expectedBytes)
 }

io/vmess/vmess.go

@@ -24,6 +24,8 @@ const (
 	Version = byte(0x01)
 
 	blockSize = 16
+
+	CryptoMessage = "c48619fe-8f02-49e0-b9e9-edf763e17e21"
 )
 
 var (
@@ -67,7 +69,7 @@ func (r *VMessRequestReader) Read(reader io.Reader) (*VMessRequest, error) {
 	// TODO: verify version number
 	request.Version = buffer[0]
 
-	nBytes, err = reader.Read(buffer[:len(request.UserId)])
+	nBytes, err = reader.Read(buffer[:core.IDBytesLen])
 	if err != nil {
 		return nil, err
 	}
@@ -78,7 +80,7 @@ func (r *VMessRequestReader) Read(reader io.Reader) (*VMessRequest, error) {
 	}
 	request.UserId = *userId
 
-  aesCipher, err := aes.NewCipher(userId.Hash([]byte("PWD")))
+	aesCipher, err := aes.NewCipher(userId.Hash([]byte(CryptoMessage)))
 	if err != nil {
 		return nil, err
 	}
@@ -181,7 +183,7 @@ func NewVMessRequestWriter() *VMessRequestWriter {
 func (w *VMessRequestWriter) Write(writer io.Writer, request *VMessRequest) error {
 	buffer := make([]byte, 0, 300)
 	buffer = append(buffer, request.Version)
-	buffer = append(buffer, request.UserId.Hash([]byte("ASK"))...)
+	buffer = append(buffer, request.UserId.TimeRangeHash(30)...)
 
 	encryptionBegin := len(buffer)
 
@@ -229,7 +231,7 @@ func (w *VMessRequestWriter) Write(writer io.Writer, request *VMessRequest) erro
 	buffer = append(buffer, paddingBuffer...)
 	encryptionEnd := len(buffer)
 
-	aesCipher, err := aes.NewCipher(request.UserId.Hash([]byte("PWD")))
+	aesCipher, err := aes.NewCipher(request.UserId.Hash([]byte(CryptoMessage)))
 	if err != nil {
 		return err
 	}

net/freedom/freedom.go

@@ -53,7 +53,7 @@ func (vconn *FreedomConnection) CloseConn(conn net.Conn, readFinish <-chan bool,
 	<-writeFinish
 	if tcpConn, ok := conn.(*net.TCPConn); ok {
 		log.Debug("Closing freedom write.")
-    tcpConn.CloseWrite();
+		tcpConn.CloseWrite()
 	}
 	<-readFinish
 	conn.Close()

net/vmess/config.go

@@ -14,7 +14,7 @@ type VMessUser struct {
 }
 
 func (u *VMessUser) ToUser() (core.User, error) {
-	id, err := core.UUIDToID(u.Id)
+	id, err := core.NewID(u.Id)
 	return core.User{id}, err
 }
 

net/vmess/vmessin.go

@@ -93,7 +93,7 @@ func (handler *VMessInboundHandler) HandleConnection(connection net.Conn) error
 	<-writeFinish
 	if tcpConn, ok := connection.(*net.TCPConn); ok {
 		log.Debug("VMessIn closing write")
-    tcpConn.CloseWrite();
+		tcpConn.CloseWrite()
 	}
 	<-readFinish
 
@@ -113,7 +113,6 @@ func (handler *VMessInboundHandler) dumpOutput(writer io.Writer, output <-chan [
 	finish <- true
 }
 
-
 type VMessInboundHandlerFactory struct {
 }
 

userset.go

@@ -1,38 +1,70 @@
 package core
 
 import (
-	"encoding/base64"
+	"time"
+)
+
+const (
+	updateIntervalSec = 10
+	cacheDurationSec  = 120
 )
 
 type UserSet struct {
 	validUserIds []ID
-	userIdsAskHash map[string]int
+	userHashes   map[string]int
+}
+
+type hashEntry struct {
+	hash    string
+	timeSec int64
 }
 
 func NewUserSet() *UserSet {
 	vuSet := new(UserSet)
 	vuSet.validUserIds = make([]ID, 0, 16)
-	vuSet.userIdsAskHash = make(map[string]int)
+	vuSet.userHashes = make(map[string]int)
+
+	go vuSet.updateUserHash(time.Tick(updateIntervalSec * time.Second))
 	return vuSet
 }
 
-func hashBytesToString(hash []byte) string {
-	return base64.StdEncoding.EncodeToString(hash)
+func (us *UserSet) updateUserHash(tick <-chan time.Time) {
+	now := time.Now().UTC()
+	lastSec := now.Unix() - cacheDurationSec
+
+	hash2Remove := make(chan hashEntry, updateIntervalSec*2)
+	lastSec2Remove := now.Unix() + cacheDurationSec
+	for {
+		now := <-tick
+		nowSec := now.UTC().Unix()
+
+		remove2Sec := nowSec - cacheDurationSec
+		if remove2Sec > lastSec2Remove {
+			for lastSec2Remove+1 < remove2Sec {
+				entry := <-hash2Remove
+				lastSec2Remove = entry.timeSec
+				delete(us.userHashes, entry.hash)
+			}
+		}
+
+		for i := lastSec + 1; i <= nowSec; i++ {
+			for idx, id := range us.validUserIds {
+				idHash := id.TimeHash(i)
+				hash2Remove <- hashEntry{string(idHash), i}
+				us.userHashes[string(idHash)] = idx
+			}
+		}
+	}
 }
 
 func (us *UserSet) AddUser(user User) error {
 	id := user.Id
 	us.validUserIds = append(us.validUserIds, id)
-
-	idBase64 := hashBytesToString(id.Hash([]byte("ASK")))
-	us.userIdsAskHash[idBase64] = len(us.validUserIds) - 1
-
 	return nil
 }
 
-func (us UserSet) IsValidUserId(askHash []byte) (*ID, bool) {
-	askBase64 := hashBytesToString(askHash)
-	idIndex, found := us.userIdsAskHash[askBase64]
+func (us UserSet) IsValidUserId(userHash []byte) (*ID, bool) {
+	idIndex, found := us.userHashes[string(userHash)]
 	if found {
 		return &us.validUserIds[idIndex], true
 	}