[Babel-users] v4-over-v6 implementation

[Théophile Bastian]

> Well, it compiles, but how would you suggest going about testing it?
> (in terms of setting up the routes in the linux kernel
> to start with). Then I'd toss a bird implementation at it and see what
> it breaks.

My test setup is usually a network of containers, around variations of 
this topology:

A --(v4+6)-- B --(v6)-- C --(v4+6)-- D

where each NIC on a v4+6 link gets an IPv4 address. In this setup, A 
should be able to reach the IPv4 addresses of C and D.

> How long has the linux kernel had the ability to do this?
> I would kind of prefer the ae numbers to be assigned sequentially
> instead of out of the experimental range. > so what happens if you get this ae on an older kernel?

I've been testing that yesterday on a Debian Stretch, which has a 4.9 
kernel (iirc). This results in errors in the logs, since babeld tries to 
insert v4-over-v6 routes, but the behaviour, as far as I was able to 
test, is correct: the route insertion is rejected by the kernel.

However, relying on a kernel error looks a bit ugly to me, and I've put 
it on my to-do list to catch the error earlier.

-- 
Théophile Bastian