Golang Buffer.Len方法代码示例

// Write implements Writer.Write().
func (this *AdaptiveWriter) Write(buffer *alloc.Buffer) error {
	nBytes, err := this.writer.Write(buffer.Value)
	if nBytes < buffer.Len() {
		_, err = this.writer.Write(buffer.Value[nBytes:])
	}
	return err
}

func Authenticate(buffer *alloc.Buffer) {
	fnvHash := fnv.New32a()
	fnvHash.Write(buffer.Value)
	buffer.PrependHash(fnvHash)

	buffer.PrependUint16(uint16(buffer.Len()))
}

func (this *SimpleAuthenticator) Open(buffer *alloc.Buffer) bool {
	len := buffer.Len()
	xtra := 4 - len%4
	if xtra != 0 {
		buffer.Slice(0, len+xtra)
	}
	xorbkd(buffer.Value)
	if xtra != 0 {
		buffer.Slice(0, len)
	}

	fnvHash := fnv.New32a()
	fnvHash.Write(buffer.Value[4:])
	if serial.BytesToUint32(buffer.Value[:4]) != fnvHash.Sum32() {
		return false
	}

	length := serial.BytesToUint16(buffer.Value[4:6])
	if buffer.Len()-6 != int(length) {
		return false
	}

	buffer.SliceFrom(6)

	return true
}

func Authenticate(buffer *alloc.Buffer) {
	fnvHash := fnv.New32a()
	fnvHash.Write(buffer.Value)

	buffer.SliceBack(4)
	fnvHash.Sum(buffer.Value[:0])

	buffer.Prepend(serial.Uint16Literal(uint16(buffer.Len())).Bytes())
}

// ToBytes returns a VMessRequest in the form of byte array.
func (request *VMessRequest) ToBytes(idHash user.CounterHash, randomRangeInt64 user.RandomInt64InRange, buffer *alloc.Buffer) (*alloc.Buffer, error) {
	if buffer == nil {
		buffer = alloc.NewSmallBuffer().Clear()
	}

	counter := randomRangeInt64(time.Now().UTC().Unix(), 30)
	hash := idHash.Hash(request.UserId.Bytes[:], counter)

	buffer.Append(hash)

	encryptionBegin := buffer.Len()

	buffer.AppendBytes(request.Version)
	buffer.Append(request.RequestIV)
	buffer.Append(request.RequestKey)
	buffer.Append(request.ResponseHeader)
	buffer.AppendBytes(request.Command)
	buffer.Append(request.Address.PortBytes())

	switch {
	case request.Address.IsIPv4():
		buffer.AppendBytes(addrTypeIPv4)
		buffer.Append(request.Address.IP())
	case request.Address.IsIPv6():
		buffer.AppendBytes(addrTypeIPv6)
		buffer.Append(request.Address.IP())
	case request.Address.IsDomain():
		buffer.AppendBytes(addrTypeDomain, byte(len(request.Address.Domain())))
		buffer.Append([]byte(request.Address.Domain()))
	}

	encryptionEnd := buffer.Len()

	fnv1a := fnv.New32a()
	fnv1a.Write(buffer.Value[encryptionBegin:encryptionEnd])

	fnvHash := fnv1a.Sum32()
	buffer.AppendBytes(byte(fnvHash>>24), byte(fnvHash>>16), byte(fnvHash>>8), byte(fnvHash))
	encryptionEnd += 4

	aesCipher, err := aes.NewCipher(request.UserId.CmdKey())
	if err != nil {
		return nil, err
	}
	aesStream := cipher.NewCFBEncrypter(aesCipher, user.Int64Hash(counter))
	aesStream.XORKeyStream(buffer.Value[encryptionBegin:encryptionEnd], buffer.Value[encryptionBegin:encryptionEnd])

	return buffer, nil
}

func (this *Listener) OnReceive(payload *alloc.Buffer, src v2net.Destination) {
	defer payload.Release()

	if valid := this.block.Open(payload); !valid {
		log.Info("KCP|Listener: discarding invalid payload from ", src)
		return
	}
	if !this.running {
		return
	}
	this.Lock()
	defer this.Unlock()
	if !this.running {
		return
	}
	if payload.Len() < 4 {
		return
	}
	conv := serial.BytesToUint16(payload.Value)
	cmd := Command(payload.Value[2])
	sourceId := src.NetAddr() + "|" + serial.Uint16ToString(conv)
	conn, found := this.sessions[sourceId]
	if !found {
		if cmd == CommandTerminate {
			return
		}
		log.Debug("KCP|Listener: Creating session with id(", sourceId, ") from ", src)
		writer := &Writer{
			id:       sourceId,
			hub:      this.hub,
			dest:     src,
			listener: this,
		}
		srcAddr := &net.UDPAddr{
			IP:   src.Address().IP(),
			Port: int(src.Port()),
		}
		conn = NewConnection(conv, writer, this.localAddr, srcAddr, this.block)
		select {
		case this.awaitingConns <- conn:
		case <-time.After(time.Second * 5):
			conn.Close()
			return
		}
		this.sessions[sourceId] = conn
	}
	conn.Input(payload.Value)
}

func (this *SimpleAuthenticator) Seal(buffer *alloc.Buffer) {
	buffer.PrependUint16(uint16(buffer.Len()))
	fnvHash := fnv.New32a()
	fnvHash.Write(buffer.Value)
	buffer.PrependHash(fnvHash)

	len := buffer.Len()
	xtra := 4 - len%4
	if xtra != 0 {
		buffer.Slice(0, len+xtra)
	}
	xorfwd(buffer.Value)
	if xtra != 0 {
		buffer.Slice(0, len)
	}
}

// ToBytes returns a VMessRequest in the form of byte array.
func (this *VMessRequest) ToBytes(timestampGenerator RandomTimestampGenerator, buffer *alloc.Buffer) (*alloc.Buffer, error) {
	if buffer == nil {
		buffer = alloc.NewSmallBuffer().Clear()
	}

	timestamp := timestampGenerator.Next()
	idHash := IDHash(this.User.AnyValidID().Bytes())
	idHash.Write(timestamp.Bytes())

	hashStart := buffer.Len()
	buffer.Slice(0, hashStart+16)
	idHash.Sum(buffer.Value[hashStart:hashStart])

	encryptionBegin := buffer.Len()

	buffer.AppendBytes(this.Version)
	buffer.Append(this.RequestIV)
	buffer.Append(this.RequestKey)
	buffer.AppendBytes(this.ResponseHeader, this.Option, byte(0), byte(0))
	buffer.AppendBytes(this.Command)
	buffer.Append(this.Port.Bytes())

	switch {
	case this.Address.IsIPv4():
		buffer.AppendBytes(addrTypeIPv4)
		buffer.Append(this.Address.IP())
	case this.Address.IsIPv6():
		buffer.AppendBytes(addrTypeIPv6)
		buffer.Append(this.Address.IP())
	case this.Address.IsDomain():
		buffer.AppendBytes(addrTypeDomain, byte(len(this.Address.Domain())))
		buffer.Append([]byte(this.Address.Domain()))
	}

	encryptionEnd := buffer.Len()

	fnv1a := fnv.New32a()
	fnv1a.Write(buffer.Value[encryptionBegin:encryptionEnd])

	fnvHash := fnv1a.Sum32()
	buffer.AppendBytes(byte(fnvHash>>24), byte(fnvHash>>16), byte(fnvHash>>8), byte(fnvHash))
	encryptionEnd += 4

	timestampHash := md5.New()
	timestampHash.Write(timestamp.HashBytes())
	iv := timestampHash.Sum(nil)
	aesStream, err := v2crypto.NewAesEncryptionStream(this.User.ID.CmdKey(), iv)
	if err != nil {
		return nil, err
	}
	aesStream.XORKeyStream(buffer.Value[encryptionBegin:encryptionEnd], buffer.Value[encryptionBegin:encryptionEnd])

	return buffer, nil
}

func (this *AuthChunkReader) Read() (*alloc.Buffer, error) {
	var buffer *alloc.Buffer
	if this.last != nil {
		buffer = this.last
		this.last = nil
	} else {
		buffer = alloc.NewBufferWithSize(4096).Clear()
	}

	if this.chunkLength == -1 {
		for buffer.Len() < 6 {
			_, err := buffer.FillFrom(this.reader)
			if err != nil {
				buffer.Release()
				return nil, io.ErrUnexpectedEOF
			}
		}
		length := serial.BytesToUint16(buffer.Value[:2])
		this.chunkLength = int(length) - 4
		this.validator = NewValidator(serial.BytesToUint32(buffer.Value[2:6]))
		buffer.SliceFrom(6)
		if buffer.Len() < this.chunkLength && this.chunkLength <= 2048 {
			_, err := buffer.FillFrom(this.reader)
			if err != nil {
				buffer.Release()
				return nil, io.ErrUnexpectedEOF
			}
		}
	} else if buffer.Len() < this.chunkLength {
		_, err := buffer.FillFrom(this.reader)
		if err != nil {
			buffer.Release()
			return nil, io.ErrUnexpectedEOF
		}
	}

	if this.chunkLength == 0 {
		buffer.Release()
		return nil, io.EOF
	}

	if buffer.Len() < this.chunkLength {
		this.validator.Consume(buffer.Value)
		this.chunkLength -= buffer.Len()
	} else {
		this.validator.Consume(buffer.Value[:this.chunkLength])
		if !this.validator.Validate() {
			buffer.Release()
			return nil, transport.ErrCorruptedPacket
		}
		leftLength := buffer.Len() - this.chunkLength
		if leftLength > 0 {
			this.last = alloc.NewBufferWithSize(leftLength + 4096).Clear()
			this.last.Append(buffer.Value[this.chunkLength:])
			buffer.Slice(0, this.chunkLength)
		}

		this.chunkLength = -1
		this.validator = nil
	}

	return buffer, nil
}