[Babel-users] Babel on itty bitty boxes

[Dave Taht]

On Thu, Mar 24, 2016 at 1:16 AM, Matthieu Boutier
<boutier at pps.univ-paris-diderot.fr> wrote:
>> my gateway (routerA) is a source specific babel, without a version
>> number but from an openwrt build about 2 months back. RouterB is a
>> cerowrt box.
>
> On routerA:
>
> 1. How did you redistribute source-specific routes

std openwrt.

> 2. Did you see them exported in babeld ?

x86 box I see:

default from 2001:556:6045:bd:1ccf:b9bb:e8da:2c77 via
fe80::16cc:20ff:fee5:64c2 dev eno1  proto babel  metric 1024  pref
medium
default from 2601:645:4103:56c0::/60 via fe80::16cc:20ff:fee5:64c2 dev
eno1  proto babel  metric 1024  pref medium

so, yep.

>
>> But: On a brand new raspberry pi3 (kernel 4.1.19-v7), same wire, I
>> guess it is either not compiled with IPV6_SUBTREES or the
>> autodetection is broken because I don't get "default from" routes, but
>> the routes inserted in the "ip -6 rules" table.
>
> Look at kernel_older_than in kernel.c, and test this function on your system.
> (You may also want to see kernel_has_ipv6_subtrees in kernel_netlink.c)

I checked and IPV6_SUBTREES is disabled in the raspbian kernel
build. I filed a bug.

https://github.com/raspberrypi/linux/issues/1370

It is straightforward to build a new kernel whenever get around to it.

(there are more than a few 4.1 kernel features I'd like to see in
there also, I imagine if I asked them for pie on pi they might get a
kick out of it.)

>> So, to the weird part. A path that is
>> routerA <-ethernet-> rpi3 <-usbwifi-> routerB
>>
>> routerB does not get the "default from" routes.
>
> Aren't they even sent on the link ? (tcpdump from rpi)

rpi3, c2, c1, x86 box are on the same switch.

I will go dump the wifi side of the pi.

>> an odroid c1, kernel 3.10.80 does not create the rules tables nor
>> default from.
>
> Are you able to create them manually ?

yes on the pi3, c1 and c2.

> sudo ip -6 rule add from 2001:bd8::/48 prio 42 table 20
> ip -6 rule show
> sudo ip -6 rule del prio 42
>
>> I honestly don't know what mainline kernel was "good"
>> for source specific routing
>
> It should be good with any (linux) kernel.  (I would be surprised if you have no support for traffic engineering rules.)

All of them seem compiled without IPV6_SUBTREES.
All of them have ip rule support. the rpi3 creates rules, the c1, c2
do not get rules, the rpi3 does not seem to be forwarding default
from.

I can certainly grant access to them (via ipv6) if you want to play,
or if anyone wants a belated christmas present?  :)

Of these it was the rpi3 that was the most exciting thing to play
with, an ideal cheap meshy router platform, given the onboard wifi did
adhoc... followed closely by the c2 (64 bit arm, 50 bucks, wow).

the c2 "feels" *way* faster than the rpi3 - but some major features
like graphics and sound don't work as yet.

Are there any well known usb sticks that work with adhoc?


> Matthieu
>