[Olsr-users] olsrd (and earlier) ipv6 problems

Saverio Proto (spam-protected)
Tue Mar 25 08:45:22 CET 2014

Hello Russel,

I understand you dont see any routes in the Kernel routing table. But
if you query the olsrd process with the txtinfo plugin di you see
there the IPv6 routes ?


2014-03-25 8:24 GMT+01:00 Henning Rogge <(spam-protected)>:
> Hi,
> what kind of IPv6 addresses are assigned on bridges and interfaces
> before and after you change the connectivity?
> OLSRd use nearly the same codepaths for IPv4 and IPv6, so I expect
> there is some "outside event" that triggers this behavior.
> Henning Rogge
> On Mon, Mar 24, 2014 at 11:44 PM, Russell Senior
> <(spam-protected)> wrote:
>> We have a network of around 60 nodes, running olsrd (and
>> earlier) in a hub and spoke topology, primarily over openvpn tunnels.
>> The nodes are running recent trunk openwrt, the hub is a gentoo box.
>> The nodes are a mixture of ar71xx, x86 and brcm47xx devices.  We
>> provision ipv6 to the nodes through hurricane electric 6in4 tunnel to
>> the well-connected hub machine, and then statically provising /64's to
>> each of the nodes and let olsrd manage the routing tables.  We also
>> run an ipv4 olsrd in parallel.
>> Recently, we encountered our first node that had its own native ipv6
>> upstream, which is preferable (as it takes the traffic load off our hub
>> box).  To avoid routing confusion, we ultimately turned olsrd ipv6 off
>> on that node.  Around the same time, we noticed that some of our nodes
>> seemed to lose their ipv6 routing.  When I checked the routing tables
>> on our hub machine (e.g. "ip -6 r"), all I saw were the local routes.
>> I have a set of devices in a test-bed in my basement where I checkout
>> newly built images where I have serial console.  My basement network
>> has its own ipv6 network through a separate hurricane electric tunnel.
>> I noticed that if I unplugged one of the devices in my test-bed, the
>> hub machine gradually (over about 30-60 seconds) got all its ipv6
>> routes back.  When I plugged in the test-device, boom, in 10-15
>> seconds, the hub machine's ipv6 routing table collapsed again.  Unplug
>> it, the routes come back.
>> Meanwhile, the ipv4 routing table is steady as a rock.
>> Eventually, I discover that an openwrt uci option ip6assign seems to
>> be causing trouble, and I disable it.  Meanwhile the same image at
>> another site does not appear to be causing any trouble, perhaps
>> because it does not have an upstream ipv6 network?
>> Then a few days ago, I look and notice that all (or virtually all) the
>> ipv6 routes are gone from our hub machine again.  This time, I go to
>> another of my test-bed devices and turn off the ipv6 olsrd there, and
>> after 30-60 seconds the routes all come back again.  This time it is
>> an x86 device (an alix2).
>> Does this sound at all familiar?  Any suggestion where to start looking?
>> --
>> Russell Senior, President
>> (spam-protected)
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