Support infiniband device about arp HOT 8 CLOSED

Neat. I'm good with that. Mind sending a PR?

from arp.

Actually, why would that check cause an issue? The surrounding code just checks for MAC addresses of at least length 6.

from arp.

Yeah, that is fine, but the if len(srcHW) != len(dstHW) fails it . My source is 12 and dst is 6

from arp.

Apologies, I haven't ever tried that. How does that work? I'd expect that you'd be ARPing to another IPoIB device on the other side that also has a 12 byte address.

The ARP packet allocates enough space for the length of the source address at the moment, so the 6 empty bytes on the destination are just ignored?

I'm happy to loosen the restriction, I'd just like to understand what's going on here. If you have some links, that'd be helpful.

from arp.

In addition, this RFC seems to indicate both addresses would be 20 bytes: https://tools.ietf.org/html/rfc4391#section-9.2.

from arp.

Maybe it's upstream for you in "net" because I think that's how you are getting MAC address.
How can I help debug this and see what is being compared at that point? Just add fmt module and print it out? I've tried but I'm fairly bad at go.

from arp.

From MetalLB:
https://github.com/danderson/metallb/blob/30e6f68bade331367ddb3a772593d137af21e4d8/internal/layer2/arp.go#L52

pkt, err := arp.NewPacket(op, a.hardwareAddr, ip, ethernet.Broadcast, ip)

As from the above, it use ethernet.Broadcast as dstHW (Gratuitous ARP). And that's why it always fail for IP over Infiniband( 20bytes)

I belief removing the check would resolve the issue or check for destHW is not equal to ethernet.Broadcast too.

EDIT: MetalLB in L2 mode uses gratuitous ARP.

from arp.

Let me know if this is all set now, thanks!

from arp.