That routing code is a red herring, it's actually never reached in the
case where wifi is already activated, because wifi remains the best IP4
connection available (given that it has a higher priority than modems).

>From what I see here, it seems like rild is just *always* setting the
route, and this is basically just a race between NM and rild: if rild
happens to write the route before NM has activated the primary; then
you'll get a valid routing table (because the rild route gets replaced
by NM's route via wifi), but if it happens after, NM rightfully no
longer cares about what happens to the routing. This *is* proper
behavior since we can't go trash routes that could be added after the
connection by a sysadmin or some other process...

I'd very much like to understand why this suddently became an issue -- I
don't think either code bases changed much in relation to routing, so
something ought to have changed in the environment on mako.

I see two options, listed in order of preference (not necessarily
feasibility):

1) Convince rild to never set up the default route. I would have hope
this to be doable via an android property that can be set, I tried to
find a property that looked related, but without results yet. It could
well not be feasible at all, sadly.

2) Ship a custom dispatcher script in lxc-android-config; to, on
purpose, trash the "boot" routing table which rild abuses to do this. I
would rather do this as a dispatcher script we ship only on touch,
because I think it's explicitly Very Very Wrong to muck with the routing
table arbitrarily for other images.

I did already test this as a workaround with the expected successful
result, see http://paste.ubuntu.com/7376744/.

3) Find a way to catch the precise, exact route using netlink in the
ofono modem plugin of NM; and explicitly RTM_DELROUTE it. This is the
safest to ship everywhere, but requires the most effort.

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https://bugs.launchpad.net/bugs/1307981

Title:
  [touch] randomly messed up routing with recent trusty images

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