Re: [lwip-users] arp failure results in newEntry != NULL assertion

[Thomas Taranowski]

On Nov 9, 2007 11:18 PM, Frédéric BERNON <address@hidden> wrote:

Hi Thomas,

 

I will suppose you use the last CVS head.

Close, it's a week or so old.
 

The difference between your both tests is that in the first one, ARP is used to found your target MAC/IP entry, but in the second one, ARP is used to found your gateway entry (so, if your gateway exists, but not your target, ARP will first find your gateway MAX address, and next, lwIP send a packet to (gateway MAC/target IP).

 

The assertion you give us is in etharp_query, if mem_malloc(MEMP_ARP_QUEUE) failed when ARP_QUEUEING=1. If you remove the assert, you got a crash. So, we need to change code to be able to work even if we don't have any MEMP_ARP_QUEUE.

 

I will take a look

Thanks for the explanation Frédéric, as I don't have familiarity with that portion of the code and caught me entirely off guard.  This is fairly high-priority for me at the moment, so I will see if I can roll a patch next week, unless you get to it first, of course :)

----- Original Message -----

From: Thomas Taranowski

To: Mailing list for lwIP users

Sent: Friday, November 09, 2007 11:48 PM

Subject: [lwip-users] arp failure results in newEntry != NULL assertion

I'm able to readily reproduce the following, and am wondering if other folks have seen similar behavior, or if it's just a problem with my port.

On my target running lwIP, I while(1) sendto() to a non-existent target on the ***LOCAL*** subnet.  
Result: newEntry!=NULL assertion from etharp.c.  lwIP failed to allocate a memp so that it could cache the outgoing packet.  Shouldn't really be an assertion, as there needs to be error handling code in place for that, but that's another issue.

On my target running lwIP, I while(1) sendto() to a non-existent target on a ***REMOTE*** subnet.
Result: code works fine

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Thomas Taranowski
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