Re: [lwip-users] lwIP malloc fail

[Kieran Mansley]

On 7 Apr 2010, at 18:31, Navcon - Pedro Paulo Santos wrote:

> 
> Using what you said I concluded that the lack of memory may occur because the 
> microcontroller doesn't recognize the ACK that comes (and it really comes, 
> because I can see it with Wireshark), and because of that, lwIP doesn't free 
> segment memory and after some tranfers it doesn't find memory to alloc.
> 
> I'm going to look for the reason that it can't recognize the ACK.

The most simple explanation would be that you've used all the available TCP 
segments by queueing data to send, and there are none left to process the 
received packet, so it gets dropped.  If you set the TCP_SND_QUEUELEN (or 
something similar - can't remember the exact name) smaller than the number of 
TCP segments then you shouldn't be able to exhaust them by queueing data to 
send.

Kieran