[lwip-users] RST sent by linux on close

[Jeff Barber]

Not an lwip problem per se (at least I don't think so), but I'm hoping
some TCP expert here can suggest a reason why this is happening:

I have a linux process (169.254.254.1) connecting to an lwIP v1.3.2
native api server (169.254.254.11 port 10).  The client closes the
socket before exiting which is always resulting in a RST being sent.
I'm trying to understand why linux would be doing that instead of just
sending FIN.

I've even gone into the code on the client side and done a
"shutdown(sock, SHUT_RDWR)" then waited 1.5 seconds before closing.
But I'm *still* seeing linux send a RST even though AFAICT all data
has been flushed and acked and  the socket seems to be fully closed
(FINs also sent and acked).  Is there something evident in the capture
that would explain why this is happening?  If I connect with telnet
instead of my custom program and wait for all data to be sent (and
ACKs to be sent), then quit from telnet, I don't see the RST being
sent.

Any help greatly appreciated.

Thanks,
Jeff

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