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

Russell Senior (spam-protected)
Fri Mar 28 11:00:34 CET 2014 

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
> >
> >
>
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