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wb2osz / direwolf

Dire Wolf is a software "soundcard" AX.25 packet modem/TNC and APRS encoder/decoder. It can be used stand-alone to observe APRS traffic, as a tracker, digipeater, APRStt gateway, or Internet Gateway (IGate). For more information, look at the bottom 1/4 of this page and in https://github.com/wb2osz/direwolf/blob/dev/doc/README.md
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Stuck on Y=1 #535

Open jmkristian opened 3 weeks ago

jmkristian commented 3 weeks ago

In some cases, Direwolf sends an inaccurate 'Y' response to an AGW client, indicating there is one frame outstanding, waiting to be transmitted. But all frames have been transmitted. It should send Y=0.

The circumstances in which this occurs seem quite specific. In my case, I connect to a BBS and send a 'b' command; the BBS responds by disconnecting immediately. Next, I connect to the same BBS, using the same TCP connection to Direwolf. At this point, Direwolf is stuck on Y=1. The attached file Y1.txt shows this behavior. It's output from Direwolf with the command line option "-d au". The inaccurate Y values appear after 11:58:09.

Y1.txt

The behavior seems correlated with the remote call sign. If I connect to a different BBS (using the same TCP connection to Direwolf), the connection starts correctly with Y=0. If I go back and connect to the problematic BBS, the connection starts with Y=1.

I used Windows 8.1, Direwolf version 1.7 and a DRA-65 audio adapter.

mfncooper commented 3 weeks ago

This is likely related to the cause of issue #534 as described here: https://github.com/wb2osz/direwolf/issues/534#issuecomment-2156674280

The data being collected for the 'Y' response is coming from the same data structure maintained in list_head. Since this data structure is never cleaned up, the second connection is reusing the same instance that was created for the first connection. That instance may contain stale data left over from the first connection that is now being provided as if it was relevant to the second connection.