RE: [lwip-users] Problem with ftp session

[Campanella, David]

Hi..

Just had a general question here...  the Telnet sessions you reference,
is it a Telnet client running on your target??  My motivation for asking
is that we maybe seeing something similar on our end.  

BTW..  didn't see the wireshark dump attached.

Thanks and Regards,

Dave Campanella
Sr. Field Applications Engineer
address@hidden
Atmel Corp.
8101 Kaiser Suite 140
Anaheim Hills, CA 92808
Phone: (925) 989-0569 Fax (714) 282-0500

-----Original Message-----
From: address@hidden
[mailto:address@hidden On
Behalf Of Jonathan Larmour
Sent: Tuesday, January 15, 2008 8:44 AM
To: Mailing list for lwIP users
Subject: Re: [lwip-users] Problem with ftp session

Thomas Taranowski wrote:
> 95% of the time my ftp/telnet apps work fine.  However, once in awhile
I
> get into a cycle where the tcp connections totally hose up.  The cause
> appears to be related to the fact that in sys_mbox_fetch(), the
> again:/goto again loop is spinning with wild abandon.  I put a counter
> inside sys_mbox_fetch, which easily upticks into the several hundreds
> within seconds of stack startup.  I've verified that the
> sys_arch_mbox_fetch is returning sane values.  The odd thing is that
> this only crops up once in awhile, and will stay around.  Last time I
> thought I had a bad ethernet card, and switched test targets, and
> everything started working.  However, now that I'm seeing it again on
> different hardware/ethernet card combo, I'm concerned that I've got a
> critical bug floating around somewhere.
> 
> I've attached a wireshark capture of the link output.  It's a portion
of
> the ftp session.  You'll see that it basically works, but will spew
out
> loads of TCP Dup ACK, TCP Retransmits, and finally drops the
connection
> at the end with a series of 7 RSTs in a row.  Presumably I'm seeing
> these cause the timers are firing way to fast.
> 
> Note: This is a custom port of lwIP to an OS I'm working on.
> 
> Any ideas on how to debug this, or what the issue is?  When this
occurs,
> I do have an inetd server start listening on several tcp ports at
system
> startup.

Given sys_mbox_fetch is spinning, I would initially suspect your port's
sys_arch_timeouts() call. It should return a list of timeouts only for
the
current thread.

Jifl
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