Golang Buffer.Len方法代码示例

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.PrependHash(fnvHash)

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

func (this *ChunkWriter) Write(payload *alloc.Buffer) error {
	totalLength := payload.Len()
	payload.SliceBack(AuthSize)
	this.auth.Authenticate(payload.Value[:0], payload.Value[AuthSize:])
	payload.PrependUint16(uint16(totalLength))
	_, err := this.writer.Write(payload.Bytes())
	return err
}

func (this *Listener) OnReceive(payload *alloc.Buffer, session *proxy.SessionInfo) {
	defer payload.Release()

	src := session.Source

	if valid := this.authenticator.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),
		}
		auth, err := this.config.GetAuthenticator()
		if err != nil {
			log.Error("KCP|Listener: Failed to create authenticator: ", err)
		}
		conn = NewConnection(conv, writer, this.Addr().(*net.UDPAddr), srcAddr, auth, this.config)
		select {
		case this.awaitingConns <- conn:
		case <-time.After(time.Second * 5):
			conn.Close()
			return
		}
		this.sessions[sourceId] = conn
	}
	conn.Input(payload.Value)
}

func (this *Server) handleUDPPayload(payload *alloc.Buffer, session *proxy.SessionInfo) {
	source := session.Source
	log.Info("Socks: Client UDP connection from ", source)
	request, err := protocol.ReadUDPRequest(payload.Value)
	payload.Release()

	if err != nil {
		log.Error("Socks: Failed to parse UDP request: ", err)
		return
	}
	if request.Data.Len() == 0 {
		request.Data.Release()
		return
	}
	if request.Fragment != 0 {
		log.Warning("Socks: Dropping fragmented UDP packets.")
		// TODO handle fragments
		request.Data.Release()
		return
	}

	log.Info("Socks: Send packet to ", request.Destination(), " with ", request.Data.Len(), " bytes")
	log.Access(source, request.Destination, log.AccessAccepted, "")
	this.udpServer.Dispatch(&proxy.SessionInfo{Source: source, Destination: request.Destination()}, request.Data, func(destination v2net.Destination, payload *alloc.Buffer) {
		response := &protocol.Socks5UDPRequest{
			Fragment: 0,
			Address:  request.Destination().Address(),
			Port:     request.Destination().Port(),
			Data:     payload,
		}
		log.Info("Socks: Writing back UDP response with ", payload.Len(), " bytes to ", destination)

		udpMessage := alloc.NewLocalBuffer(2048).Clear()
		response.Write(udpMessage)

		this.udpMutex.RLock()
		if !this.accepting {
			this.udpMutex.RUnlock()
			return
		}
		nBytes, err := this.udpHub.WriteTo(udpMessage.Value, destination)
		this.udpMutex.RUnlock()
		udpMessage.Release()
		response.Data.Release()
		if err != nil {
			log.Error("Socks: failed to write UDP message (", nBytes, " bytes) to ", destination, ": ", err)
		}
	})
}

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)
	}
}

func DecodeUDPPacket(user *protocol.User, payload *alloc.Buffer) (*protocol.RequestHeader, *alloc.Buffer, error) {
	rawAccount, err := user.GetTypedAccount()
	if err != nil {
		return nil, nil, errors.New("Shadowsocks|UDP: Failed to parse account: " + err.Error())
	}
	account := rawAccount.(*ShadowsocksAccount)

	ivLen := account.Cipher.IVSize()
	iv := payload.Value[:ivLen]
	payload.SliceFrom(ivLen)

	stream, err := account.Cipher.NewDecodingStream(account.Key, iv)
	if err != nil {
		return nil, nil, errors.New("Shadowsocks|UDP: Failed to initialize decoding stream: " + err.Error())
	}
	stream.XORKeyStream(payload.Value, payload.Value)

	authenticator := NewAuthenticator(HeaderKeyGenerator(account.Key, iv))
	request := &protocol.RequestHeader{
		Version: Version,
		User:    user,
		Command: protocol.RequestCommandUDP,
	}

	addrType := (payload.Value[0] & 0x0F)
	if (payload.Value[0] & 0x10) == 0x10 {
		request.Option |= RequestOptionOneTimeAuth
	}

	if request.Option.Has(RequestOptionOneTimeAuth) {
		payloadLen := payload.Len() - AuthSize
		authBytes := payload.Value[payloadLen:]

		actualAuth := authenticator.Authenticate(nil, payload.Value[0:payloadLen])
		if !bytes.Equal(actualAuth, authBytes) {
			return nil, nil, errors.New("Shadowsocks|UDP: Invalid OTA.")
		}

		payload.Slice(0, payloadLen)
	}

	payload.SliceFrom(1)

	switch addrType {
	case AddrTypeIPv4:
		request.Address = v2net.IPAddress(payload.Value[:4])
		payload.SliceFrom(4)
	case AddrTypeIPv6:
		request.Address = v2net.IPAddress(payload.Value[:16])
		payload.SliceFrom(16)
	case AddrTypeDomain:
		domainLength := int(payload.Value[0])
		request.Address = v2net.DomainAddress(string(payload.Value[1 : 1+domainLength]))
		payload.SliceFrom(1 + domainLength)
	default:
		return nil, nil, errors.New("Shadowsocks|UDP: Unknown address type")
	}

	request.Port = v2net.PortFromBytes(payload.Value[:2])
	payload.SliceFrom(2)

	return request, payload, 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
}