netdev - Re: [RFC 0/1] Appletalk AARP probe broken by receipt of own broadcasts.

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Date:   Sun, 19 Aug 2018 14:09:43 +1200
From:   Craig McGeachie <slapdau@...il.com>
To:     Andrew Lunn <andrew@...n.ch>
Cc:     "David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org,
        Craig McGeachie <slapdau@...oo.com.au>
Subject: Re: [RFC 0/1] Appletalk AARP probe broken by receipt of own
 broadcasts.

On 19/08/18 13:32, Andrew Lunn wrote:
> On Sun, Aug 19, 2018 at 01:07:38PM +1200, Craig McGeachie wrote:
>> I'm hoping I can find someone able and willing to test this patch. That
>> requires someone still using netatalk 2.2.x with DDP, or some other DDP
>> userspace application. This feels like a longshot.
>>
>> When netatalk 2.2.x starts up with DDP and sets the Appletalk node
>> address, the kernel AARP code sends a probe packet for the address. It
>> then receives its own probe packet and interprets that as some other
>> node also trying to claim the address. It increments the address, tries
>> again, and fails again ad nausium. Eventually the kernel module gives up
>> and returns to netatalk which terminates with an error that it cannot
>> get a node address.
> 
> Hi Craig
> 
> What Ethernet device are you seeing this problem with?
> 
> I'm not sure an Ethernet device should receive its own broadcasts.
> This might be a driver bug, not an AARP bug.
> 
>       Andrew
> 

I run inside Virtualbox with the Realtek PCIe GBE Family Controller.

Assuming I'm reading /sys/class/net/enp0s3/driver correctly, it's using 
the e1000 driver.

However, it might not be the ethernet driver's fault. I've been a bit 
loose with terminology. Appletalk AARP probe packets aren't ethernet 
broadcasts as such; they're multicast packets, via the psnap driver, to 
hardware address 09:00:07:ff:ff:ff.

Cheers,
Craig.