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NTP fix infinite loop #82

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Merged
merged 4 commits into from
Jan 14, 2023
Merged

NTP fix infinite loop #82

merged 4 commits into from
Jan 14, 2023

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@BiffoBear
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@BiffoBear BiffoBear commented Dec 20, 2022

fixes #56 NTP.get_time calls self._sock.recv() from a while True: loop. This results in an infinite loop if no data is received. The UDP protocol can lose packets, so this is possible.

Added retries using exponential fallback to give slow networks a chance. If there is no response, a TimeoutError is raised.

        max_retries = 4
        for retry in range(max_retries):
            self._sock.sendto(self._pkt_buf_, (self._ntp_server, 123))
            end_time = time.monotonic() + 0.2 * 2**retry
            while time.monotonic() < end_time:
                data = self._sock.recv()

anecdata
anecdata approved these changes Dec 27, 2022
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LGTM! Tested on W5100S. Observed replies instantly, after retries, and also observed TimeoutError: No reply from NTP server after 4 attempts..

FoamyGuy
FoamyGuy approved these changes Jan 14, 2023
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Looks good to me. Tested successfully on Feather TFT ESP32-S2

I got some successes and some failures that now report the new error instead of hanging forever.

@FoamyGuy FoamyGuy merged commit abdec8a into adafruit:main Jan 14, 2023
adafruit-adabot added a commit to adafruit/Adafruit_CircuitPython_Bundle that referenced this pull request Jan 15, 2023
@adafruit-adabot
Automated update by Adabot (adafruit/adabot@85a9103)
3a64ff6 
Updating https://github.com/adafruit/Adafruit_CircuitPython_Wiznet5k to 1.13.3 from 1.13.1:
  > Merge pull request adafruit/Adafruit_CircuitPython_Wiznet5k#82 from BiffoBear/NTP_fix_infinite_loop
  > Merge pull request adafruit/Adafruit_CircuitPython_Wiznet5k#86 from BiffoBear/_GLOBAL_constants

Updating https://github.com/adafruit/Adafruit_CircuitPython_Bundle/circuitpython_library_list.md to NA from NA:
  > Updated download stats for the libraries
@BiffoBear BiffoBear deleted the NTP_fix_infinite_loop branch January 17, 2023 00:12
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@anecdata anecdata anecdata approved these changes

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Intermittent hangs in NTP.get_time()

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@BiffoBear @FoamyGuy @anecdata