[lwip-devel] [bug #60415] Large data transmissions (from lwip to client) sometimes stop

[SviMik]

Follow-up Comment #1, bug #60415 (project lwip):

I have successfully reproduced the bug on a smaller amount of data. Using curl
option --limit-rate it can be reproduced on my PC in ~8 seconds, the rate I
choose (5M or 10K) doesn't matter, the only point is that my PC tries to
throttle the speed by decreasing its window, but instead of throttling the
transfer stops completely and does not resume ever.

Here's the Wireshark dump:
http://svimik.com/lwipstall4.pcapng [407KB]

I have also enabled debug LwIP logging:
http://svimik.com/lwipstall4.log [670KB]

Here I tried to combine it with my commentary of what I thing is happening:
http://svimik.com/lwipstall4_comments.txt [5KB]

Long story short: The Windows starts ignoring both LwIP retransmissions and
keepalive requests for no apparent reason, and plays dead until LwIP gives up
by timeout and sends RST, only then Windows replies with ACK to the RST
packet.

The only clue in both dumps is that client sends window updates to lwip,
either setting it to zero pausing the transfer completely, or some small
value, then sets it back to 65535 causing LwIP to continue sending the data,
but then something wrong happens and I can't understand what exactly. The
Windows sends Dup ACKs asking to retransmit some packet, I see in Wireshark
that LwIP retransmits the packet, but Windows ignores it.

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