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Re: [lwip-users] loopif bug ?
From: |
Kieran Mansley |
Subject: |
Re: [lwip-users] loopif bug ? |
Date: |
Thu, 27 Feb 2003 17:26:00 +0000 (GMT) |
On Thu, 27 Feb 2003, Andreas Stenius wrote:
> Hi all,
>
> I've run across a misshap with the loopif ( TCP only, not UDP ).
> When connecting to 'localhost' using the loopif interface, the tcp packet is
> processed on the
> receiver side before the send process is completed, resulting in a reference
> to NULL in tcp_process:
Yep, looks like a bug to me. Quite an interesting one in fact.
Demonstrates nicely that no one else is using the loopif interface. In
theory I guess it could affect a non-loopback interface if the network
were fast enough.
I'd file a bug report on savannah if I were you, but it should be fairly
straightforward to fix. Moving the portion of code in tcp_output that
updates pcb->unacked to before the call to tcp_output_segment should do
the trick. Although interestingly if TCP_TCPLEN is never greater than 0,
pcb->unacked will remain NULL, and we'll still get a seg fault. Is it
possible for this to happen? (admittedly it would be a pretty dull
connection, but if it's possible we should be able to cope with it).
Kieran