[B.A.T.M.A.N.] avahi broadcasts over two-radio batman.. dropped?

[B.A.T.M.A.N.] avahi broadcasts over two-radio batman.. dropped?

[Guido Iribarren]

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Hello again,
can't determine exactly since when, but avahi is acting funny in
QuintanaLibre :(

two computers (pbx and veci) connected to different nodes in the mesh
can't always resolve hostnames through avahi

pbx ]=eth==[ nicoyjesi --> .. --> .. --> wlan1(czuk)wlan0 <-->
natychucho ]==eth=[ veci
(cf. attached dotgraph)

question from pbx is broadcasted perfectly and reaches veci,
veci replies, natychucho broadcasts the replly through wifi , gets to
czuk wlan0, but czuk doesn't re-broadcast it , silently dropping the
packet.

relevant tcpdump
http://pastebin.com/6xLmDqe5
you can see question coming in through czuk(wlan1), rebroadcasted
through czuk(wlan0), reach veci, veci reply, czuk(wlan0) gets reply,
but doesn't retransmit it through czuk(wlan1) :(

iptables @ czuk looks sane
http://pastebin.com/mFUFuNdC

## czuk has two wifi interfaces, both in ap mode, managed by batman
## natychucho is connected to wlan0 in client mode,
## and cisterna is client to wlan1. no WDS whatsoever.
root@czuk:~# batctl if
wlan0: active
wlan1: active
root@czuk:~# brctl show
bridge name	bridge id		STP enabled	interfaces
br-lan		8000.54e6fcb98e2b	no		eth0
							bat0

complete live config can be lurked in
https://bitbucket.org/nicoechaniz/quintanalibre-configs/src/d9bd3603824d/czuk/overlay

I don't find any reason batman would be involved in this, but iptables
is discarded as a suspect, and AFAICS there are no other factors
messing with the packets (maybe it's a bit late night :) ). No bridges
whatsoever.
In fact, packet is catched by batctl td coming in at wlan0.

Any hints or experiences will be greatly appreciated as always!

Gui

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Re: [B.A.T.M.A.N.] avahi broadcasts over two-radio batman.. dropped?

[Nicolás Echániz]

On 07/19/2012 01:20 AM, Guido Iribarren wrote:
> Hello again,
> can't determine exactly since when, but avahi is acting funny in
> QuintanaLibre :(
> 
[...]

> I don't find any reason batman would be involved in this, but iptables
> is discarded as a suspect, and AFAICS there are no other factors
> messing with the packets (maybe it's a bit late night :) ). No bridges
> whatsoever.
> In fact, packet is catched by batctl td coming in at wlan0.
> 
> Any hints or experiences will be greatly appreciated as always!


Sorry to just bump this thread but we are connecting more people to the
net here and avahi is a central piece of our
small-town-community-network experiment. ...so, if anyone can think of
further testing/debugging that we could do, we will be more than pleased
to collaborate, as usual!


abraxi,
NicoEchániz

Re: [B.A.T.M.A.N.] avahi broadcasts over two-radio batman.. dropped?

[Antonio Quartulli]

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Hello Guido,

On Thu, Jul 19, 2012 at 01:20:15AM -0300, Guido Iribarren wrote:
> Hello again,
> can't determine exactly since when, but avahi is acting funny in
> QuintanaLibre :(
> 
> two computers (pbx and veci) connected to different nodes in the mesh
> can't always resolve hostnames through avahi
> 
> pbx ]=eth==[ nicoyjesi --> .. --> .. --> wlan1(czuk)wlan0 <-->
> natychucho ]==eth=[ veci
> (cf. attached dotgraph)
> 
> question from pbx is broadcasted perfectly and reaches veci,
> veci replies, natychucho broadcasts the replly through wifi , gets to
> czuk wlan0, but czuk doesn't re-broadcast it , silently dropping the
> packet.
> 
> relevant tcpdump
> http://pastebin.com/6xLmDqe5
> you can see question coming in through czuk(wlan1), rebroadcasted
> through czuk(wlan0), reach veci, veci reply, czuk(wlan0) gets reply,
> but doesn't retransmit it through czuk(wlan1) :(
> 

I see..

> iptables @ czuk looks sane
> http://pastebin.com/mFUFuNdC
> 

I trust you on this because there are too many rules :) (have you tried a
'iptables -F' just in case?)

> ## czuk has two wifi interfaces, both in ap mode, managed by batman
> ## natychucho is connected to wlan0 in client mode,
> ## and cisterna is client to wlan1. no WDS whatsoever.
> root@czuk:~# batctl if
> wlan0: active
> wlan1: active
> root@czuk:~# brctl show
> bridge name	bridge id		STP enabled	interfaces
> br-lan		8000.54e6fcb98e2b	no		eth0
> 							bat0
> 
> complete live config can be lurked in
> https://bitbucket.org/nicoechaniz/quintanalibre-configs/src/d9bd3603824d/czuk/overlay
> 
> I don't find any reason batman would be involved in this, but iptables
> is discarded as a suspect, and AFAICS there are no other factors
> messing with the packets (maybe it's a bit late night :) ). No bridges
> whatsoever.
> In fact, packet is catched by batctl td coming in at wlan0.
>
> Any hints or experiences will be greatly appreciated as always!
>

is BLA2 enabled on czuk?

Cheers,

-- 
Antonio Quartulli

..each of us alone is worth nothing..
Ernesto "Che" Guevara

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Re: [B.A.T.M.A.N.] avahi broadcasts over two-radio batman.. dropped?

[Nicolás Echániz]

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On 07/24/2012 04:06 AM, Antonio Quartulli wrote:

> I trust you on this because there are too many rules :) (have you
> tried a 'iptables -F' just in case?)

Antonio, I tried iptables -F today but nothing changed. Tried iptables
- -F along the whole route, and still no difference.

> is BLA2 enabled on czuk?

yes BLA2 is enabled on every node by default. I've also tried
disabling in every involved node but it made no difference.


I'm testing now on a different route (see Guido's graphic on first
mail for reference): from a computer connected through ethernet (no
batman) at nicoyjesi to one connected the same way to marisa-mr. The
same thing happens: when I run avahi-resolve it gets to the computer
at marisa's, which responds as it should, but the response never gets
to the other end.

this is what the setup looks like:

pc1===nicoyjesi==b==nogal - - - - marisa-blt==b==marisa-mr===pc2

==b== is bat-enabled ethernet
=== ethernet
- - - - bat-enabled adhoc link

I'm out of ideas here... but I'll sleep it over and chat again with
Guido tomorrow to try to find out some way to at least reduce this to
the smallest possible setup to reproduce the problem.

On a side-note, avahi is not completely broken, it actually works
(from user experience) as if there were no batman on the net, those on
the same phisical portion of the net can see and interact with each
other just fine; it does not even always fail when more nodes are
involved I just can't seem to find a pattern just yet.


cheers,
Nico


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