1

Мне нужно использовать websockify в качестве прокси. Окончательная настройка будет:

  • веб-сокет на веб-странице подключается к серверу websockify на той же машине
  • Сервер websockify инициирует соединение с программой сокета TCP, слушающей где-то еще (в данном случае, на той же машине)
  • TCP-сокет получает информацию, выполняет вычисления, отвечает на websockify
  • websockify получает ответ и отправляет информацию в сокет на веб-странице
  • ответ представлен в браузере пользователя

Однако по какой-то причине websockify отказывается передавать информацию дальше и получает сообщение FIN раньше, чем ожидалось. Websockify говорит: «Не поддерживается: неизвестный код операции 0x01».

Чтобы исследовать этот случай, я создал MWE и перехватил трафик с помощью tcpdump .

Установка выглядит следующим образом:

  • Во-первых, я запускаю netcat -v -v -l -p 40000 - это приложение, которое мы хотим получать информацию

  • Затем я запускаю websockify --verbose 50000 localhost:40000 - это команда прокси

  • Наконец, я запускаю wscat -c localhost:50000 - это приложение, устанавливающее соединение websocket с прокси websockify

Как только я отправляю что-то с помощью wscat , wscat с wscat сбрасывается с кодом 1003. Цитата RFC 6455:

1003 указывает, что конечная точка завершает соединение, потому что она приняла тип данных, которые она не может принять (например, конечная точка, которая понимает только текстовые данные, МОЖЕТ отправить это, если она получит двоичное сообщение).

Вот визуальное представление этой установки (сообщение erorr «отключено, потому что закрыто 1003» написано таким образом, потому что я вручную изменил источник для получения дополнительной информации о разъединении):

Вот представление Wireshark данных:

и вот пакеты с номерами 11, 12, 13 и 14, которые привлекли мое внимание:

Frame 11: 81 bytes on wire (648 bits), 81 bytes captured (648 bits)
    Encapsulation type: Ethernet (1)
    Arrival Time: Sep 19, 2017 20:35:46.491762000 CEST
    [Time shift for this packet: 0.000000000 seconds]
    Epoch Time: 1505846146.491762000 seconds
    [Time delta from previous captured frame: 3.788711000 seconds]
    [Time delta from previous displayed frame: 3.788711000 seconds]
    [Time since reference or first frame: 3.887638000 seconds]
    Frame Number: 11
    Frame Length: 81 bytes (648 bits)
    Capture Length: 81 bytes (648 bits)
    [Frame is marked: False]
    [Frame is ignored: False]
    [Protocols in frame: eth:ethertype:ip:tcp:http:websocket:data-text-lines]
Ethernet II, Src: 00:00:00_00:00:00 (00:00:00:00:00:00), Dst: 00:00:00_00:00:00 (00:00:00:00:00:00)
    Destination: 00:00:00_00:00:00 (00:00:00:00:00:00)
        Address: 00:00:00_00:00:00 (00:00:00:00:00:00)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
    Source: 00:00:00_00:00:00 (00:00:00:00:00:00)
        Address: 00:00:00_00:00:00 (00:00:00:00:00:00)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
    Type: IPv4 (0x0800)
Internet Protocol Version 4, Src: 127.0.0.1, Dst: 127.0.0.1
    0100 .... = Version: 4
    .... 0101 = Header Length: 20 bytes (5)
    Differentiated Services Field: 0x00 (DSCP: CS0, ECN: Not-ECT)
        0000 00.. = Differentiated Services Codepoint: Default (0)
        .... ..00 = Explicit Congestion Notification: Not ECN-Capable Transport (0)
    Total Length: 67
    Identification: 0x1581 (5505)
    Flags: 0x02 (Don't Fragment)
        0... .... = Reserved bit: Not set
        .1.. .... = Don't fragment: Set
        ..0. .... = More fragments: Not set
    Fragment offset: 0
    Time to live: 64
    Protocol: TCP (6)
    Header checksum: 0x2732 [validation disabled]
    [Header checksum status: Unverified]
    Source: 127.0.0.1
    Destination: 127.0.0.1
    [Source GeoIP: Unknown]
    [Destination GeoIP: Unknown]
TCP Src Port: 53832, Dst Port: 50000, Seq: 225, Ack: 130, Len: 15
    Src Port: 53832
    Dest Port: 50000
    [Stream index: 0]
    [TCP Segment Len: 15]
    Sequence number: 225    (relative sequence number)
    [Next sequence number: 240    (relative sequence number)]
    Acknowledgment number: 130    (relative ack number)
    1000 .... = Header Length: 32 bytes (8)
    Flags: 0x018 (PSH, ACK)
        000. .... .... = Reserved: Not set
        ...0 .... .... = Nonce: Not set
        .... 0... .... = Congestion Window Reduced (CWR): Not set
        .... .0.. .... = ECN-Echo: Not set
        .... ..0. .... = Urgent: Not set
        .... ...1 .... = Acknowledgment: Set
        .... .... 1... = Push: Set
        .... .... .0.. = Reset: Not set
        .... .... ..0. = Syn: Not set
        .... .... ...0 = Fin: Not set
        [TCP Flags: ·······AP···]
    Window size value: 350
    [Calculated window size: 44800]
    [Window size scaling factor: 128]
    Checksum: 0xfe37 [unverified]
    [Checksum Status: Unverified]
    Urgent pointer: 0
    Options: (12 bytes), No-Operation (NOP), No-Operation (NOP), Timestamps
        TCP Option - No-Operation (NOP)
            Kind: No-Operation (1)
        TCP Option - No-Operation (NOP)
            Kind: No-Operation (1)
        TCP Option - Timestamps: TSval 1764320477, TSecr 1764319312
            Kind: Time Stamp Option (8)
            Length: 10
            Timestamp value: 1764320477
            Timestamp echo reply: 1764319312
    [SEQ/ACK analysis]
        [iRTT: 0.000021000 seconds]
        [Bytes in flight: 15]
        [Bytes sent since last PSH flag: 15]
    TCP payload (15 bytes)
    [PDU Size: 15]
WebSocket
    1... .... = Fin: True
    .000 .... = Reserved: 0x0
    .... 0001 = Opcode: Text (1)
    1... .... = Mask: True
    .000 1001 = Payload length: 9
    Masking-Key: 2f0bda1c
    Masked payload
    Payload
Line-based text data
    alamakota

Frame 12: 102 bytes on wire (816 bits), 102 bytes captured (816 bits)
    Encapsulation type: Ethernet (1)
    Arrival Time: Sep 19, 2017 20:35:46.492378000 CEST
    [Time shift for this packet: 0.000000000 seconds]
    Epoch Time: 1505846146.492378000 seconds
    [Time delta from previous captured frame: 0.000616000 seconds]
    [Time delta from previous displayed frame: 0.000616000 seconds]
    [Time since reference or first frame: 3.888254000 seconds]
    Frame Number: 12
    Frame Length: 102 bytes (816 bits)
    Capture Length: 102 bytes (816 bits)
    [Frame is marked: False]
    [Frame is ignored: False]
    [Protocols in frame: eth:ethertype:ip:tcp:http:websocket]
Ethernet II, Src: 00:00:00_00:00:00 (00:00:00:00:00:00), Dst: 00:00:00_00:00:00 (00:00:00:00:00:00)
    Destination: 00:00:00_00:00:00 (00:00:00:00:00:00)
        Address: 00:00:00_00:00:00 (00:00:00:00:00:00)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
    Source: 00:00:00_00:00:00 (00:00:00:00:00:00)
        Address: 00:00:00_00:00:00 (00:00:00:00:00:00)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
    Type: IPv4 (0x0800)
Internet Protocol Version 4, Src: 127.0.0.1, Dst: 127.0.0.1
    0100 .... = Version: 4
    .... 0101 = Header Length: 20 bytes (5)
    Differentiated Services Field: 0x00 (DSCP: CS0, ECN: Not-ECT)
        0000 00.. = Differentiated Services Codepoint: Default (0)
        .... ..00 = Explicit Congestion Notification: Not ECN-Capable Transport (0)
    Total Length: 88
    Identification: 0xd42e (54318)
    Flags: 0x02 (Don't Fragment)
        0... .... = Reserved bit: Not set
        .1.. .... = Don't fragment: Set
        ..0. .... = More fragments: Not set
    Fragment offset: 0
    Time to live: 64
    Protocol: TCP (6)
    Header checksum: 0x686f [validation disabled]
    [Header checksum status: Unverified]
    Source: 127.0.0.1
    Destination: 127.0.0.1
    [Source GeoIP: Unknown]
    [Destination GeoIP: Unknown]
TCP Src Port: 50000, Dst Port: 53832, Seq: 130, Ack: 240, Len: 36
    Src Port: 50000
    Dest Port: 53832
    [Stream index: 0]
    [TCP Segment Len: 36]
    Sequence number: 130    (relative sequence number)
    [Next sequence number: 166    (relative sequence number)]
    Acknowledgment number: 240    (relative ack number)
    1000 .... = Header Length: 32 bytes (8)
    Flags: 0x018 (PSH, ACK)
        000. .... .... = Reserved: Not set
        ...0 .... .... = Nonce: Not set
        .... 0... .... = Congestion Window Reduced (CWR): Not set
        .... .0.. .... = ECN-Echo: Not set
        .... ..0. .... = Urgent: Not set
        .... ...1 .... = Acknowledgment: Set
        .... .... 1... = Push: Set
        .... .... .0.. = Reset: Not set
        .... .... ..0. = Syn: Not set
        .... .... ...0 = Fin: Not set
        [TCP Flags: ·······AP···]
    Window size value: 350
    [Calculated window size: 44800]
    [Window size scaling factor: 128]
    Checksum: 0xfe4c [unverified]
    [Checksum Status: Unverified]
    Urgent pointer: 0
    Options: (12 bytes), No-Operation (NOP), No-Operation (NOP), Timestamps
        TCP Option - No-Operation (NOP)
            Kind: No-Operation (1)
        TCP Option - No-Operation (NOP)
            Kind: No-Operation (1)
        TCP Option - Timestamps: TSval 1764320478, TSecr 1764320477
            Kind: Time Stamp Option (8)
            Length: 10
            Timestamp value: 1764320478
            Timestamp echo reply: 1764320477
    [SEQ/ACK analysis]
        [This is an ACK to the segment in frame: 11]
        [The RTT to ACK the segment was: 0.000616000 seconds]
        [iRTT: 0.000021000 seconds]
        [Bytes in flight: 36]
        [Bytes sent since last PSH flag: 36]
    TCP payload (36 bytes)
    [PDU Size: 36]
WebSocket
    1... .... = Fin: True
    .000 .... = Reserved: 0x0
    .... 1000 = Opcode: Connection Close (8)
    0... .... = Mask: False
    .010 0010 = Payload length: 34
    Payload
        Close
            Status code: Unsupported Data (1003)
            Reason: Unsupported: Unknown opcode 0x01

Frame 13: 66 bytes on wire (528 bits), 66 bytes captured (528 bits)
    Encapsulation type: Ethernet (1)
    Arrival Time: Sep 19, 2017 20:35:46.492394000 CEST
    [Time shift for this packet: 0.000000000 seconds]
    Epoch Time: 1505846146.492394000 seconds
    [Time delta from previous captured frame: 0.000016000 seconds]
    [Time delta from previous displayed frame: 0.000016000 seconds]
    [Time since reference or first frame: 3.888270000 seconds]
    Frame Number: 13
    Frame Length: 66 bytes (528 bits)
    Capture Length: 66 bytes (528 bits)
    [Frame is marked: False]
    [Frame is ignored: False]
    [Protocols in frame: eth:ethertype:ip:tcp]
Ethernet II, Src: 00:00:00_00:00:00 (00:00:00:00:00:00), Dst: 00:00:00_00:00:00 (00:00:00:00:00:00)
    Destination: 00:00:00_00:00:00 (00:00:00:00:00:00)
        Address: 00:00:00_00:00:00 (00:00:00:00:00:00)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
    Source: 00:00:00_00:00:00 (00:00:00:00:00:00)
        Address: 00:00:00_00:00:00 (00:00:00:00:00:00)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
    Type: IPv4 (0x0800)
Internet Protocol Version 4, Src: 127.0.0.1, Dst: 127.0.0.1
    0100 .... = Version: 4
    .... 0101 = Header Length: 20 bytes (5)
    Differentiated Services Field: 0x00 (DSCP: CS0, ECN: Not-ECT)
        0000 00.. = Differentiated Services Codepoint: Default (0)
        .... ..00 = Explicit Congestion Notification: Not ECN-Capable Transport (0)
    Total Length: 52
    Identification: 0x1582 (5506)
    Flags: 0x02 (Don't Fragment)
        0... .... = Reserved bit: Not set
        .1.. .... = Don't fragment: Set
        ..0. .... = More fragments: Not set
    Fragment offset: 0
    Time to live: 64
    Protocol: TCP (6)
    Header checksum: 0x2740 [validation disabled]
    [Header checksum status: Unverified]
    Source: 127.0.0.1
    Destination: 127.0.0.1
    [Source GeoIP: Unknown]
    [Destination GeoIP: Unknown]
TCP Src Port: 53832, Dst Port: 50000, Seq: 240, Ack: 166, Len: 0
    Src Port: 53832
    Dest Port: 50000
    [Stream index: 0]
    [TCP Segment Len: 0]
    Sequence number: 240    (relative sequence number)
    Acknowledgment number: 166    (relative ack number)
    1000 .... = Header Length: 32 bytes (8)
    Flags: 0x010 (ACK)
        000. .... .... = Reserved: Not set
        ...0 .... .... = Nonce: Not set
        .... 0... .... = Congestion Window Reduced (CWR): Not set
        .... .0.. .... = ECN-Echo: Not set
        .... ..0. .... = Urgent: Not set
        .... ...1 .... = Acknowledgment: Set
        .... .... 0... = Push: Not set
        .... .... .0.. = Reset: Not set
        .... .... ..0. = Syn: Not set
        .... .... ...0 = Fin: Not set
        [TCP Flags: ·······A····]
    Window size value: 350
    [Calculated window size: 44800]
    [Window size scaling factor: 128]
    Checksum: 0xfe28 [unverified]
    [Checksum Status: Unverified]
    Urgent pointer: 0
    Options: (12 bytes), No-Operation (NOP), No-Operation (NOP), Timestamps
        TCP Option - No-Operation (NOP)
            Kind: No-Operation (1)
        TCP Option - No-Operation (NOP)
            Kind: No-Operation (1)
        TCP Option - Timestamps: TSval 1764320478, TSecr 1764320478
            Kind: Time Stamp Option (8)
            Length: 10
            Timestamp value: 1764320478
            Timestamp echo reply: 1764320478
    [SEQ/ACK analysis]
        [This is an ACK to the segment in frame: 12]
        [The RTT to ACK the segment was: 0.000016000 seconds]
        [iRTT: 0.000021000 seconds]

Frame 14: 106 bytes on wire (848 bits), 106 bytes captured (848 bits)
    Encapsulation type: Ethernet (1)
    Arrival Time: Sep 19, 2017 20:35:46.494661000 CEST
    [Time shift for this packet: 0.000000000 seconds]
    Epoch Time: 1505846146.494661000 seconds
    [Time delta from previous captured frame: 0.002267000 seconds]
    [Time delta from previous displayed frame: 0.002267000 seconds]
    [Time since reference or first frame: 3.890537000 seconds]
    Frame Number: 14
    Frame Length: 106 bytes (848 bits)
    Capture Length: 106 bytes (848 bits)
    [Frame is marked: False]
    [Frame is ignored: False]
    [Protocols in frame: eth:ethertype:ip:tcp:http:websocket]
Ethernet II, Src: 00:00:00_00:00:00 (00:00:00:00:00:00), Dst: 00:00:00_00:00:00 (00:00:00:00:00:00)
    Destination: 00:00:00_00:00:00 (00:00:00:00:00:00)
        Address: 00:00:00_00:00:00 (00:00:00:00:00:00)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
    Source: 00:00:00_00:00:00 (00:00:00:00:00:00)
        Address: 00:00:00_00:00:00 (00:00:00:00:00:00)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
    Type: IPv4 (0x0800)
Internet Protocol Version 4, Src: 127.0.0.1, Dst: 127.0.0.1
    0100 .... = Version: 4
    .... 0101 = Header Length: 20 bytes (5)
    Differentiated Services Field: 0x00 (DSCP: CS0, ECN: Not-ECT)
        0000 00.. = Differentiated Services Codepoint: Default (0)
        .... ..00 = Explicit Congestion Notification: Not ECN-Capable Transport (0)
    Total Length: 92
    Identification: 0x1583 (5507)
    Flags: 0x02 (Don't Fragment)
        0... .... = Reserved bit: Not set
        .1.. .... = Don't fragment: Set
        ..0. .... = More fragments: Not set
    Fragment offset: 0
    Time to live: 64
    Protocol: TCP (6)
    Header checksum: 0x2717 [validation disabled]
    [Header checksum status: Unverified]
    Source: 127.0.0.1
    Destination: 127.0.0.1
    [Source GeoIP: Unknown]
    [Destination GeoIP: Unknown]
TCP Src Port: 53832, Dst Port: 50000, Seq: 240, Ack: 166, Len: 40
    Src Port: 53832
    Dest Port: 50000
    [Stream index: 0]
    [TCP Segment Len: 40]
    Sequence number: 240    (relative sequence number)
    [Next sequence number: 280    (relative sequence number)]
    Acknowledgment number: 166    (relative ack number)
    1000 .... = Header Length: 32 bytes (8)
    Flags: 0x018 (PSH, ACK)
        000. .... .... = Reserved: Not set
        ...0 .... .... = Nonce: Not set
        .... 0... .... = Congestion Window Reduced (CWR): Not set
        .... .0.. .... = ECN-Echo: Not set
        .... ..0. .... = Urgent: Not set
        .... ...1 .... = Acknowledgment: Set
        .... .... 1... = Push: Set
        .... .... .0.. = Reset: Not set
        .... .... ..0. = Syn: Not set
        .... .... ...0 = Fin: Not set
        [TCP Flags: ·······AP···]
    Window size value: 350
    [Calculated window size: 44800]
    [Window size scaling factor: 128]
    Checksum: 0xfe50 [unverified]
    [Checksum Status: Unverified]
    Urgent pointer: 0
    Options: (12 bytes), No-Operation (NOP), No-Operation (NOP), Timestamps
        TCP Option - No-Operation (NOP)
            Kind: No-Operation (1)
        TCP Option - No-Operation (NOP)
            Kind: No-Operation (1)
        TCP Option - Timestamps: TSval 1764320478, TSecr 1764320478
            Kind: Time Stamp Option (8)
            Length: 10
            Timestamp value: 1764320478
            Timestamp echo reply: 1764320478
    [SEQ/ACK analysis]
        [iRTT: 0.000021000 seconds]
        [Bytes in flight: 40]
        [Bytes sent since last PSH flag: 40]
    TCP payload (40 bytes)
    [PDU Size: 40]
WebSocket
    1... .... = Fin: True
    .000 .... = Reserved: 0x0
    .... 1000 = Opcode: Connection Close (8)
    1... .... = Mask: True
    .010 0010 = Payload length: 34
    Masking-Key: 3daec4d6
    Masked payload
    Payload
        Close
            Status code: Unsupported Data (1003)
            Reason: Unsupported: Unknown opcode 0x01

Кажется, что wscat отправляет код операции (0x1), который websockify понимает как 0x01 и не может распознать, но я не знаю почему.

Как мне заставить эту настройку работать? Я пытался подключиться к websockify с различными программами (реализация websocket браузера, альтернативы wscat ), но все они терпят неудачу.

|источник

1 ответ1

0

Я столкнулся с той же проблемой:

socket.send("hi"); // websockify chokes

... который был исправлен этим:

b = new Blob(["hi", "\n"], {type: 'text/plain'});
socket.send(b); // works as expected
|источник

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