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Prevent uncleaned external interface IP to cause firmware race condition #113

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Prevent uncleaned external interface IP to cause firmware race condition #113

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  • Remove ordering code for external interface IPs
  • [WIP] Prevent uncleaned external interface IP to cause firmware race condition

@swagner-de
Remove ordering code for external interface IPs
a1833d0 
`external_fixed_ips` was ordered to become a stable primary IP address
for the interface. This code is not necessary anymore, as if there are
more than 1 fixed IPs on the external interface,
`ASR1KPluginBase._update_router_gw_info()` will record these IPs in the
NAT pool RouterAtts. `GatewayInterface._ip_address()` will then again
use this information and determine the stable primary IP of the
GatwayInterface. Consequently an ordering is not needed at this place
anymore.

This code was also making sure that each supplied fixed IP got a
prefixlen. I am unsure how it would even get at this place, without a
prefixlen, as everything needs to have a subnet which determines the
prefixlen.
@swagner-de
[WIP] Prevent uncleaned external interface IP to cause firmware race …
e592e81 
…condition

The current firmware mal-allocates an external interfaces NAT pool (the
pointer to the hash-table, I presume) if there is an external interface
with the same IP in another VRF. We believe this is erroneous behavior
as VRFs are supposed to carry overlapping IP spaces, yet _the vendor_
argues otherwise.

Generally we would like to maintain the support of overlapping NAT
overload IPs at least from a driver perspective as theoretically this
would be valid in OpenStack with multiple adress scopes, never the less
it is unlikely to be seen in our infra.

This commit implements a preflight check, checking if any other outside
interface is present that carries the same IP as our to be programmed
interface. If that is, we must check if that is an uncleaned residue
from a VRF that is still to be cleaned or if it is a valid interface. If
it is not, we delete that interface and program the new interface with
the matching IP, thereby preventing the mal-allocation of the internal
NAT pool.
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@swagner-de