Fix ASH reject condition amplification bug by puddly · Pull Request #699 · zigpy/bellows

puddly · 2025-11-25T20:59:18Z

When communicating with OpenThread firmware, we get into tight loops when the firmware manages to respond with a semi-plausible frame. Our ASH implementation rejects it by sending a CANCEL byte and a NakFrame, which prompts the firmware to send more data, etc. This isn't right. We should enter a "reject" state and wait until the firmware sends something sensible.

See home-assistant/core#156966 (comment).

2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Sending frame 32*CANCEL RstFrame() FLAG
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Sending data  1a1a1a1a1a1a1a1a1a1a1a1a1a1a1a1a1a1a1a1a1a1a1a1a1a1a1a1a1a1a1a1ac038bc7e
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Received data 7e8006704672616d696e67206572726f7220363a205bcafd7e7e80067031412031412031412031412031412031412031412031412031412031412031412031412031412031412031412031412031412031412031412031412031412031412031412031412031412031412031412031412031412031412031412031412043302033382042435d0a89257e
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Failed to parse frame bytearray(b'\x80\x06pFraming error 6: [\xca\xfd')
Traceback (most recent call last):
  File "/lib/python3.13/site-packages/bellows/ash.py", line 470, in data_received
    frame = parse_frame(data)
  File "/lib/python3.13/site-packages/bellows/ash.py", line 350, in parse_frame
    return frame.from_bytes(data)
           ~~~~~~~~~~~~~~~~^^^^^^
  File "/lib/python3.13/site-packages/bellows/ash.py", line 219, in from_bytes
    control, data = cls._unwrap(data)
                    ~~~~~~~~~~~^^^^^^
  File "/lib/python3.13/site-packages/bellows/ash.py", line 156, in _unwrap
    raise ParsingError(
    ...<2 lines>...
    )
bellows.ash.ParsingError: Invalid CRC bytes in frame bytearray(b'\x80\x06pFraming error 6: [\xca\xfd'): expected 6e1e, got cafd
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Sending frame CANCEL NakFrame(res=0, ncp_ready=0, ack_num=0) FLAG
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Sending data  1aa0547d3a7e
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Failed to parse frame bytearray(b'\x80\x06p1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A C0 38 BC]\n\x89%')
Traceback (most recent call last):
  File "/lib/python3.13/site-packages/bellows/ash.py", line 470, in data_received
    frame = parse_frame(data)
  File "/lib/python3.13/site-packages/bellows/ash.py", line 350, in parse_frame
    return frame.from_bytes(data)
           ~~~~~~~~~~~~~~~~^^^^^^
  File "/lib/python3.13/site-packages/bellows/ash.py", line 219, in from_bytes
    control, data = cls._unwrap(data)
                    ~~~~~~~~~~~^^^^^^
  File "/lib/python3.13/site-packages/bellows/ash.py", line 156, in _unwrap
    raise ParsingError(
    ...<2 lines>...
    )
bellows.ash.ParsingError: Invalid CRC bytes in frame bytearray(b'\x80\x06p1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A C0 38 BC]\n\x89%'): expected 2c68, got 8925
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Sending frame CANCEL NakFrame(res=0, ncp_ready=0, ack_num=0) FLAG
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Sending data  1aa0547d3a7e
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Received data 7e8006704672616d696e67206572726f7220363a205bcafd7e7e80067031412041302035342031415d0a074b7e7e8006704672616d696e67206572726f7220363a205bcafd7e7e80067031412041302035342031415d0a074b7e
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Failed to parse frame bytearray(b'\x80\x06pFraming error 6: [\xca\xfd')
Traceback (most recent call last):
  File "/lib/python3.13/site-packages/bellows/ash.py", line 470, in data_received
    frame = parse_frame(data)
  File "/lib/python3.13/site-packages/bellows/ash.py", line 350, in parse_frame
    return frame.from_bytes(data)
           ~~~~~~~~~~~~~~~~^^^^^^
  File "/lib/python3.13/site-packages/bellows/ash.py", line 219, in from_bytes
    control, data = cls._unwrap(data)
                    ~~~~~~~~~~~^^^^^^
  File "/lib/python3.13/site-packages/bellows/ash.py", line 156, in _unwrap
    raise ParsingError(
    ...<2 lines>...
    )
bellows.ash.ParsingError: Invalid CRC bytes in frame bytearray(b'\x80\x06pFraming error 6: [\xca\xfd'): expected 6e1e, got cafd
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Sending frame CANCEL NakFrame(res=0, ncp_ready=0, ack_num=0) FLAG
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Sending data  1aa0547d3a7e
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Failed to parse frame bytearray(b'\x80\x06p1A A0 54 1A]\n\x07K')
Traceback (most recent call last):
  File "/lib/python3.13/site-packages/bellows/ash.py", line 470, in data_received
    frame = parse_frame(data)
  File "/lib/python3.13/site-packages/bellows/ash.py", line 350, in parse_frame
    return frame.from_bytes(data)
           ~~~~~~~~~~~~~~~~^^^^^^
  File "/lib/python3.13/site-packages/bellows/ash.py", line 219, in from_bytes
    control, data = cls._unwrap(data)
                    ~~~~~~~~~~~^^^^^^
  File "/lib/python3.13/site-packages/bellows/ash.py", line 156, in _unwrap
    raise ParsingError(
    ...<2 lines>...
    )
bellows.ash.ParsingError: Invalid CRC bytes in frame bytearray(b'\x80\x06p1A A0 54 1A]\n\x07K'): expected f488, got 074b
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Sending frame CANCEL NakFrame(res=0, ncp_ready=0, ack_num=0) FLAG
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Sending data  1aa0547d3a7e
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Failed to parse frame bytearray(b'\x80\x06pFraming error 6: [\xca\xfd')
Traceback (most recent call last):
  File "/lib/python3.13/site-packages/bellows/ash.py", line 470, in data_received
    frame = parse_frame(data)
  File "/lib/python3.13/site-packages/bellows/ash.py", line 350, in parse_frame
    return frame.from_bytes(data)
           ~~~~~~~~~~~~~~~~^^^^^^
  File "/lib/python3.13/site-packages/bellows/ash.py", line 219, in from_bytes
    control, data = cls._unwrap(data)
                    ~~~~~~~~~~~^^^^^^
  File "/lib/python3.13/site-packages/bellows/ash.py", line 156, in _unwrap
    raise ParsingError(
    ...<2 lines>...
    )
bellows.ash.ParsingError: Invalid CRC bytes in frame bytearray(b'\x80\x06pFraming error 6: [\xca\xfd'): expected 6e1e, got cafd
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Sending frame CANCEL NakFrame(res=0, ncp_ready=0, ack_num=0) FLAG
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Sending data  1aa0547d3a7e
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Failed to parse frame bytearray(b'\x80\x06p1A A0 54 1A]\n\x07K')
Traceback (most recent call last):
  File "/lib/python3.13/site-packages/bellows/ash.py", line 470, in data_received
    frame = parse_frame(data)
  File "/lib/python3.13/site-packages/bellows/ash.py", line 350, in parse_frame
    return frame.from_bytes(data)
           ~~~~~~~~~~~~~~~~^^^^^^
  File "/lib/python3.13/site-packages/bellows/ash.py", line 219, in from_bytes
    control, data = cls._unwrap(data)
                    ~~~~~~~~~~~^^^^^^
  File "/lib/python3.13/site-packages/bellows/ash.py", line 156, in _unwrap
    raise ParsingError(
    ...<2 lines>...
    )
bellows.ash.ParsingError: Invalid CRC bytes in frame bytearray(b'\x80\x06p1A A0 54 1A]\n\x07K'): expected f488, got 074b
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Sending frame CANCEL NakFrame(res=0, ncp_ready=0, ack_num=0) FLAG
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Sending data  1aa0547d3a7e
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Received data 7e8006704672616d696e67206572726f7220363a205bcafd7e7e80
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Failed to parse frame bytearray(b'\x80\x06pFraming error 6: [\xca\xfd')
Traceback (most recent call last):
  File "/lib/python3.13/site-packages/bellows/ash.py", line 470, in data_received
    frame = parse_frame(data)
  File "/lib/python3.13/site-packages/bellows/ash.py", line 350, in parse_frame
    return frame.from_bytes(data)
           ~~~~~~~~~~~~~~~~^^^^^^
  File "/lib/python3.13/site-packages/bellows/ash.py", line 219, in from_bytes
    control, data = cls._unwrap(data)
                    ~~~~~~~~~~~^^^^^^
  File "/lib/python3.13/site-packages/bellows/ash.py", line 156, in _unwrap
    raise ParsingError(
    ...<2 lines>...
    )
bellows.ash.ParsingError: Invalid CRC bytes in frame bytearray(b'\x80\x06pFraming error 6: [\xca\xfd'): expected 6e1e, got cafd
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Sending frame CANCEL NakFrame(res=0, ncp_ready=0, ack_num=0) FLAG
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Sending data  1aa0547d3a7e
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Received data 067031412041302035342031415d0a074b7e
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Failed to parse frame bytearray(b'\x80\x06p1A A0 54 1A]\n\x07K')
Traceback (most recent call last):
  File "/lib/python3.13/site-packages/bellows/ash.py", line 470, in data_received
    frame = parse_frame(data)
  File "/lib/python3.13/site-packages/bellows/ash.py", line 350, in parse_frame
    return frame.from_bytes(data)
           ~~~~~~~~~~~~~~~~^^^^^^
  File "/lib/python3.13/site-packages/bellows/ash.py", line 219, in from_bytes
    control, data = cls._unwrap(data)
                    ~~~~~~~~~~~^^^^^^
  File "/lib/python3.13/site-packages/bellows/ash.py", line 156, in _unwrap
    raise ParsingError(
    ...<2 lines>...
    )
bellows.ash.ParsingError: Invalid CRC bytes in frame bytearray(b'\x80\x06p1A A0 54 1A]\n\x07K'): expected f488, got 074b
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Sending frame CANCEL NakFrame(res=0, ncp_ready=0, ack_num=0) FLAG
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Sending data  1aa0547d3a7e
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Received data 7e8006704672616d696e67206572726f7220363a205bcafd7e7e80067031412041302035342031415d0a074b7e7e8006704672616d696e67206572726f7220363a205bcafd7e7e80067031412041302035342031415d0a074b7e7e8006704672616d696e67206572726f7220363a205bcafd7e7e80067031412041302035342031415d0a074b7e7e8006704672616d696e67206572726f7220363a205bcafd7e7e80067031412041302035342031415d0a074b7e
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Failed to parse frame bytearray(b'\x80\x06pFraming error 6: [\xca\xfd')
Traceback (most recent call last):
  File "/lib/python3.13/site-packages/bellows/ash.py", line 470, in data_received
    frame = parse_frame(data)
  File "/lib/python3.13/site-packages/bellows/ash.py", line 350, in parse_frame
    return frame.from_bytes(data)
           ~~~~~~~~~~~~~~~~^^^^^^
  File "/lib/python3.13/site-packages/bellows/ash.py", line 219, in from_bytes
    control, data = cls._unwrap(data)
                    ~~~~~~~~~~~^^^^^^
  File "/lib/python3.13/site-packages/bellows/ash.py", line 156, in _unwrap
    raise ParsingError(
    ...<2 lines>...
    )
bellows.ash.ParsingError: Invalid CRC bytes in frame bytearray(b'\x80\x06pFraming error 6: [\xca\xfd'): expected 6e1e, got cafd
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Sending frame CANCEL NakFrame(res=0, ncp_ready=0, ack_num=0) FLAG
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Sending data  1aa0547d3a7e
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Failed to parse frame bytearray(b'\x80\x06p1A A0 54 1A]\n\x07K')
Traceback (most recent call last):
  File "/lib/python3.13/site-packages/bellows/ash.py", line 470, in data_received
    frame = parse_frame(data)
  File "/lib/python3.13/site-packages/bellows/ash.py", line 350, in parse_frame
    return frame.from_bytes(data)
           ~~~~~~~~~~~~~~~~^^^^^^
  File "/lib/python3.13/site-packages/bellows/ash.py", line 219, in from_bytes
    control, data = cls._unwrap(data)
                    ~~~~~~~~~~~^^^^^^
  File "/lib/python3.13/site-packages/bellows/ash.py", line 156, in _unwrap
    raise ParsingError(
    ...<2 lines>...
    )
bellows.ash.ParsingError: Invalid CRC bytes in frame bytearray(b'\x80\x06p1A A0 54 1A]\n\x07K'): expected f488, got 074b
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Sending frame CANCEL NakFrame(res=0, ncp_ready=0, ack_num=0) FLAG
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Sending data  1aa0547d3a7e
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Failed to parse frame bytearray(b'\x80\x06pFraming error 6: [\xca\xfd')
Traceback (most recent call last):
  File "/lib/python3.13/site-packages/bellows/ash.py", line 470, in data_received
    frame = parse_frame(data)
  File "/lib/python3.13/site-packages/bellows/ash.py", line 350, in parse_frame
    return frame.from_bytes(data)
           ~~~~~~~~~~~~~~~~^^^^^^
  File "/lib/python3.13/site-packages/bellows/ash.py", line 219, in from_bytes
    control, data = cls._unwrap(data)
                    ~~~~~~~~~~~^^^^^^
  File "/lib/python3.13/site-packages/bellows/ash.py", line 156, in _unwrap
    raise ParsingError(
    ...<2 lines>...
    )
bellows.ash.ParsingError: Invalid CRC bytes in frame bytearray(b'\x80\x06pFraming error 6: [\xca\xfd'): expected 6e1e, got cafd
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Sending frame CANCEL NakFrame(res=0, ncp_ready=0, ack_num=0) FLAG
2025-11-25 21:37:31 emscripten bellows.ash[42] DEBUG Sending data  1aa0547d3a7e

codecov · 2025-11-25T21:01:08Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.53%. Comparing base (1ad5b57) to head (1bf919b).
⚠️ Report is 2 commits behind head on dev.

Additional details and impacted files

@@            Coverage Diff             @@
##              dev     #699      +/-   ##
==========================================
- Coverage   99.55%   99.53%   -0.03%     
==========================================
  Files          58       58              
  Lines        4054     4070      +16     
==========================================
+ Hits         4036     4051      +15     
- Misses         18       19       +1

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bellows/ash.py

Fix ASH reject condition amplification bug

aa3d62d

Add test case with real device data

1bf919b

puddly merged commit 639099f into zigpy:dev Nov 25, 2025
11 of 12 checks passed

TheJulianJES reviewed Nov 25, 2025

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puddly mentioned this pull request Nov 25, 2025

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Fix ASH reject condition amplification bug#699

Fix ASH reject condition amplification bug#699
puddly merged 2 commits intozigpy:devfrom
puddly:puddly/ash-amplification-fix

puddly commented Nov 25, 2025

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