Re: [lwip-users] Patch for bug 23119

[Kieran Mansley]

On Wed, 2009-03-11 at 04:43 -0700, Ken Smith wrote:
> When I do tcpdump on the bridge, I get no
> output from my device.  It thinks it's trying to get out to the
> network but no packets are actually coming out.

That sounds like the cause of the problems.  I would try and diagnose
why no packets are coming out of your device.  The log you present
suggests that lwIP is trying to retransmit the SYN, but gives no hint at
why this wouldn't make it on to the wire.  

> I've attached two versions of my lwipopts.h file and output from a
> call to stats_display(). 

In the stats file there is this bit:

MEM TCP_PCB
        avail: 1
        used: 1
        max: 1
        err: 4

This looks like you might be running out of TCP PCBs.  You could try
increasing the number that are available and see if that helps, although
I'm not sure how it would end up with the symptoms you describe.

The other interesting bit in the stats is that you're running out of MEM
ARP_QUEUE fields.  This suggests that packets are being buffered by ARP
while waiting for a reply.  If it didn't get a reply to its ARP queries
(or if the ARP queries never made it out of the device) that would
explain why no other traffic is sent.  

So it looks like lwIP is doing the right thing, but that something is
preventing the device from sending or receiving packets.  Are you sure
your driver is working correctly?

Kieran