[Olsr-dev] [Olsr-users] olsrd 0.6.6.1 (and earlier) ipv6 problems

Henning Rogge (spam-protected)
Fri Mar 28 11:01:27 CET 2014 

What?

but your routing tables only contains "ETX 1.0" paths... which means
they are single hop!

Henning

On Fri, Mar 28, 2014 at 11:00 AM, Russell Senior
<(spam-protected)> wrote:
> Without the ipv6 olsrd, the nodes can't route to each other, it seems.  I
> picked two I had turned off, and tried ping6'ing between them and got 100%
> packet loss.
>
>
> On Fri, Mar 28, 2014 at 2:54 AM, Henning Rogge <(spam-protected)> wrote:
>>
>> Hi,
>>
>> as far as I can see each "leaf" node can see each other leaf node over
>> the OpenVPN, right?
>>
>> So you are only using Olsrd to distribute HNAs?
>>
>> Henning Rogge
>>
>> On Fri, Mar 28, 2014 at 10:48 AM, Russell Senior
>> <(spam-protected)> wrote:
>> > The central server, ::407, is running OpenVPN in server mode.  The
>> > "leaf"
>> > nodes all connect to it via OpenVPN client mode with a tap interface.
>> > We
>> > statically provision the IPv6 addresses on the vpn.
>> >
>> > And yes, the OpenVPN links are still active.  We are running an IPv4
>> > instance of olsrd (same version) in parallel and those routes (to the
>> > very
>> > same devices) are not affected.
>> >
>> > We see the problem when particular (though varying) nodes olsrd ipv6
>> > instances are started/stopped.  Sometimes the nodes are running 0.6.6.1,
>> > and
>> > sometimes 0.6.4.  It doesn't seem to be specific.  The central server is
>> > running 0.6.6.1 now, but we saw the same thing earlier (which is why I
>> > upgraded) on 0.6.4.
>> >
>> > One other potential clue (it doesn't make very much sense, because I
>> > know
>> > there are much bigger networks than ours), I've never seen more than 186
>> > ipv6 routes on ::407.  We seem to see the problem when we try to exceed
>> > that.  I'm going to try to confirm that.
>> >
>> >
>> > On Fri, Mar 28, 2014 at 2:34 AM, Henning Rogge <(spam-protected)> wrote:
>> >>
>> >> Hi,
>> >>
>> >> I must admit that I am not convinced that its an Olsrd bug what we are
>> >> seeing...
>> >>
>> >> If I see it correctly Olsrd is running over the VPN interface
>> >> connection (interface name "vpn"), right?
>> >>
>> >> Is the VPN connection between the nodes still active during the route
>> >> loss? Most of the nodes seem to have direct connections and the "30
>> >> seconds until recovery" sounds like an ETX value slowly going down and
>> >> then dropping the link.
>> >>
>> >> Henning
>> >>
>> >> On Fri, Mar 28, 2014 at 10:11 AM, Saverio Proto <(spam-protected)>
>> >> wrote:
>> >> > Hello Russel,
>> >> >
>> >> > looking at this:
>> >> >   https://personaltelco.net/~russell/olsrd/olsrd-routes-before.txt
>> >> >   https://personaltelco.net/~russell/olsrd/olsrd-routes-during.txt
>> >> >   https://personaltelco.net/~russell/olsrd/olsrd-routes-after.txt
>> >> >
>> >> > it looks like IPv6 routes are removed from the olsrd database. So I
>> >> > is
>> >> > actually the olsrd daemon involved.
>> >> >
>> >> > do you know if there is a previous stable version of olsrd where this
>> >> > bug/behaviour is not present ?
>> >> >
>> >> > In my opinion the fastest way to track the bug is to try different
>> >> > versions of olsrd with "git bisect" method.
>> >> >
>> >> > The first step is to tell us if there is a version of olsrd that is
>> >> > not affected by this problem.
>> >> >
>> >> > thanks
>> >> >
>> >> > I cc: olsrd-dev
>> >> >
>> >> > Saverio
>> >> >
>> >> >
>> >> > 2014-03-27 10:37 GMT+01:00 Russell Senior
>> >> > <(spam-protected)>:
>> >> >>>>>>> "Henning" == Henning Rogge <(spam-protected)>
>> >> >>>>>>> writes:
>> >> >>
>> >> >> Henning> On 03/26/2014 07:41 PM, Russell Senior wrote:
>> >> >>>> Anybody get a chance to look at the strace?  I see a:
>> >> >>
>> >> >> Henning> strace and packet dumps are much too lowlevel to directly
>> >> >> Henning> hunt problems like this. Thats why Saverios question about
>> >> >> Henning> txtinfo good, because it gives you a much more high-level
>> >> >> Henning> view on what is going on.
>> >> >>
>> >> >> I had not installed the modules previously, so that interface wasn't
>> >> >> immediately available.  It is now.
>> >> >>
>> >> >> [...]
>> >> >>
>> >> >> Henning> Okay, lets get back to the high-level view.
>> >> >>
>> >> >> Henning> To interpret the events you described we need a list of
>> >> >> Henning> nodes, with their interface IPs and the connectivity
>> >> >> between
>> >> >> Henning> them.
>> >> >>
>> >> >> Here is the list of neighbors of 2001:470:e962::407.  The addresses
>> >> >> listed are on the public wifi.  The OpenVPN addresses of each node
>> >> >> are
>> >> >> a permutation, e.g. if the public wifi addr is
>> >> >> 2001:470:e962:wxyz::1,
>> >> >> then the OpenVPN address of the node is 2001:470:e962::wxyz.
>> >> >>
>> >> >> None of the nodes connect directly, everything goes through ::407.
>> >> >>
>> >> >> From curl -6 http://localhost:$port/neighbors
>> >> >>
>> >> >>   https://personaltelco.net/~russell/olsrd/olsrd-neighbors.txt
>> >> >>
>> >> >> Henning> I am also a bit worried about your usage of bridges
>> >> >> Henning> connected to mesh interfaces.  Normally you should no
>> >> >> bridge
>> >> >> Henning> any interface that OLSR uses for meshing.  Mixing routing
>> >> >> Henning> (L3) and bridging (L2) can go wrong in very creative ways.
>> >> >>
>> >> >> I don't understand how the bridges could be a problem in this case.
>> >> >> This is a hub and spoke topology.  One openvpn server in the middle,
>> >> >> nodes at the edges.  None of the nodes interconnect otherwise.  Olsr
>> >> >> is broadcast on the wifi in case there are any olsrd devices nearby,
>> >> >> but, again, there is no overlap in the wifi coverage (and if there
>> >> >> were physically, they are on different SSIDs and wouldn't overlap
>> >> >> logically).
>> >> >>
>> >> >> Can you explain more about what in particularly would make you
>> >> >> worry?
>> >> >> This configuration has been stable for us on ipv4 for years and also
>> >> >> on ipv6 until very recently, since late 2012 at least.  So, I
>> >> >> suspect
>> >> >> a bug.  Somewhere.
>> >> >>
>> >> >> Henning> Txtinfo output would be good (especially /route) would be
>> >> >> Henning> good to see...  before the problem, during the problem and
>> >> >> Henning> after the recovery.
>> >> >>
>> >> >> I'm using curl -6 http://localhost:$port/routes to get the following
>> >> >> data, before, during and after turning on an ipv6 olsrd on a
>> >> >> particular node (2001:470:e962:11c1::1).
>> >> >>
>> >> >>   https://personaltelco.net/~russell/olsrd/olsrd-routes-before.txt
>> >> >>   https://personaltelco.net/~russell/olsrd/olsrd-routes-during.txt
>> >> >>   https://personaltelco.net/~russell/olsrd/olsrd-routes-after.txt
>> >> >>
>> >> >> Henning> It would also help if you can reduce the number of nodes
>> >> >> Henning> while still replicating the problem to a minimum.
>> >> >>
>> >> >> I don't have that level of control, unfortunately.  When I notice
>> >> >> that
>> >> >> the ipv6 routes have collapsed, I pick a likely seeming node (maybe
>> >> >> because it had been plugged in recently) and turn off ipv6 olsrd,
>> >> >> and
>> >> >> over 30-60 seconds, magically the routes all come back.  My luck in
>> >> >> guessing the right node to turn off is a little bit "too good", if
>> >> >> you
>> >> >> know what I mean, so that I am not sure there is anything
>> >> >> particularly
>> >> >> unique about the node I choose.  But, nevertheless, turning it off
>> >> >> seems to help, generally.
>> >> >>
>> >> >> FWIW, I'm including olsrd versions here.  The central machine ::407
>> >> >> is
>> >> >> running 0.6.6.1, compiled from the tarball.  The nodes have the
>> >> >> following versions, all built from openwrt routing feed sources.
>> >> >>
>> >> >>
>> >> >> https://personaltelco.net/~russell/olsrd/olsrd-versions-by-node.txt
>> >> >>
>> >> >> Here is a table listing the frequency of each openwrt version:
>> >> >>
>> >> >>       1 0.6.3-3
>> >> >>      33 0.6.4-1
>> >> >>       1 0.6.5.1-1
>> >> >>       1 0.6.5.1-2
>> >> >>       7 0.6.5.2-1
>> >> >>       1 0.6.5.3-1
>> >> >>       2 0.6.5.4-1
>> >> >>       2 0.6.6-2
>> >> >>       7 0.6.6-3
>> >> >>      11 0.6.6.1-1
>> >> >>
>> >> >>
>> >> >> --
>> >> >> Russell Senior, President
>> >> >> (spam-protected)
>> >> >>
>> >> >> --
>> >> >> Olsr-users mailing list
>> >> >> (spam-protected)
>> >> >> https://lists.olsr.org/mailman/listinfo/olsr-users
>> >> >
>> >> > --
>> >> > Olsr-dev mailing list
>> >> > (spam-protected)
>> >> > https://lists.olsr.org/mailman/listinfo/olsr-dev
>> >
>> >
>
>

More information about the Olsr-dev mailing list