Default route over link-local network unsupported in native zones

[hww3]

I have a set of hosts on networks (at OVH, in particular) where zones are created with networking over the admin interface but with IP subnets different than the global zone. The default route for these zones is through the default router on the admin network. In the zone, this means that there is a link-local route to the router on the admin IP subnet, and the default route is this address.

Example:

GZ admin IP: 1.2.3.4/24 default router: 1.2.3.254

Zone:
"nics": [
{
"mac": "00:01:02:03:04:05",
"nic_tag": "admin",
"netmask": "255.255.255.255",
"gateways": ["1.2.3.254"],
"ips": [
2.3.4.5/32"
],
"primary": true
}
],
"routes": {
"1.2.3.254": "nics[0]"
}

Unfortunately, this doesn't work out of the box: net-routing-setup sets up the default route before any static routes. When the default route is on a network accessible via a link-local route, adding the default route fails.

Creating link-local routes before the default or other static routes should prevent this problem. It would seem that always creating link-local routes first should not cause problems, as they should always be directly accessible without a next-hop.

I have a patch for this (as well as for lx_init and dockerinit) and can create PRs for them, assuming this theory isn't fatally flawed.