[lwip-users] Dual MAC addresses

[Ben Bobbitt]

I’m using the UC3A chip on the EVK1100 and am using the software framework provided by atmel, based on the 1.2.0 lwIP and FreeRTOS. 

 

I’ve added a simple UDP interface and am using DHCP to get an IP address.   In the Ethernet.c module, I am assigning a MAC address.   The DHCP process works as expected, and the wireshark shows the expected MAC address during the DHCP and ARP messages that are part of the IP assignment process.  When I attempt to communicate to the UDP port, and the sending device (laptop) does and ARP request, the chip responds to the ARP request with a different MAC address than the one I have assigned.  Communication over UDP at the application level then results in messages being passed to/from the expected (assigned) MAC.     

 

I’m assigning the address to the MACB netif, but in stepping through the code, it appears that there is a second netif that has been assigned somewhere with a different MAC address.  I can’t find where that is occurring, and I’m certainly not doing it in any of the code I have added.  I’m wondering if there are known issues with the 1.2.0 implementation of DHCP or some other module. 

 

I’m concerned that this may be related to another issue, where sometimes the app doesn’t respond at all to an ARP request, even though the code does recognize the IP as itself ( I’ve stepped through that ), but it doesn’t send the reply out on the wire correctly.   I get all the way to where the code calls the function to send a reply  - netif->linkoutput(netif, p);   but nothing appears on the wire. 

 

Has anyone else seen this, or perhaps know what might be the issue?  It would be much appreciated. 

 

-Ben

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