[Kimchi-devel] [RFC PATCH] List IPs of VM Ifaces

[Christy Perez]

On 05/27/2015 11:32 AM, Christy Perez wrote:
> Thanks guys! I'll look into both those.
> 
> On 05/27/2015 11:21 AM, Crístian Deives wrote:
>> On 27-05-2015 13:19, Aline Manera wrote:
>>>
>>> Hi Christy,
>>>
>>> Your patch looks good.
>>>
>>> I just have one suggestion. There is a python module name scapy that
>>> has some ARP methods.
>>> On Ubuntu the package is python-scapy.
>>> I am not sure it is available in all major Linux distribution, but I
>>> think we could take a look on it.

I looked into the scapy package, and it looks like a *lot* of overhead
to get arp cache entries. The documentation's not that great (the scapy
website search even hung), so I grepped the source and poked around in
layers/l2.py. I couldn't find a straight-forward way to get ARP cache
entries. There's a method called getmacbyip, but it looks like it
requires some setup:

>>> scapy.layers.l2.getmacbyip('192.168.0.1')

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python2.7/site-packages/scapy/layers/l2.py", line 57,
in getmacbyip
    iff,a,gw = conf.route.route(ip)
AttributeError: 'NoneType' object has no attribute 'route'

So, unless you know there's a simple way to do this and I'm missing it,
I don't think this package will actually beneficial to us.

>>
>> Or you could read the file /proc/net/arp. It's pretty much the same
>> output of "arp -n" and it doesn't require new dependencies..
>>

Is it guaranteed that this file will exist on every distro? This seems
to be the simplest way to go.