[libvirt] [PATCH 5/5] libvirt_nss: Report newer addresses first

[Michal Privoznik]

On 7/15/19 10:16 AM, Erik Skultety wrote:
> On Sat, Jul 13, 2019 at 12:58:38PM +0200, Michal Privoznik wrote:
>> Ideally, a software that's translating domain names would iterate
>> over all addresses the NSS returned, but some software does not
>> bother (e.g. ping). What happens is that for instance when
>> installing a guest, it's assigned one IP address but once it's
>> installed and rebooted it gets a different IP address (because
>> client ID used for the first DHCP traffic when installing the
>> guest was generated dynamically and never saved so after reboot
>> the guest generated new ID which resulted in different IP address
>> to be assigned). This results in 'ping $domain' not working
>> properly as it still pings the old IP address. Well, it might -
>> NSS plugin does not guarantee any order of addresses.
>>
>> To resolve this problem, we can sort the array just before
>> returning it to the caller (ping) so that the newer IP addresses
>> come before older ones.
>>
>> Reported-by: Andrea Bolognani <abologna at redhat.com>
>> Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
>> ---
> ...
> 
>>       {
>>           "ip-address": "192.168.122.254",
>>           "mac-address": "52:54:00:3a:b5:0c",
>>           "hostname": "gentoo",
>> -        "expiry-time": 2000000000
>> +        "expiry-time": 2000000001
> 
> So, why is ^this specific change needed? In the test, you're expecting
> 192.168.122.[197-199], 192.168.122.199 has expiry time of 1900000000, so the
> test would still work.
> 
> 192.168.122.254 is only assumed in a gentoo test twice, but there are no other
> addresses to sort in those cases, so the expiry time in there should not matter
> right?
> 
> With the explanation of the above:
> Reviewed-by: Erik Skultety <eskultet at redhat.com>
> 

Oh right, I don't understand how it got there. I'm removing it before 
pushing.

Thanks for the review!

Michal