Howto set up a layer 2 etherip tunnel between two bridge(4)?

[Johan Ihren <johani%johani.org@localhost>]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

I want a layer 2 tunnel between two bridges in different servers.  
Connected to the bridges are various xen DOMUs. But I fail completely  
to figure out how to set up the tunnel.

After some failed attempts involving gre(4) and gif(4) I've come to  
believe that what I want is etherip(4). Unfortunately etherip is not  
included in any standard kernel (why?) so it is necessary to compile a  
custom kernel. I have the new kernel running on the two systems "boxA"  
and "boxB". Unfortunately the etherip(4) documentation is a bit  
lacking for me. In particular I stumble on the paragraph:

        "A tunnel configured for the previous (undocumented) implementation
        will work with just renaming the device from gif to etherip."

Is it just me, or wouldn't the lack of gif documentation be all the  
more reason to document etherip slightly more verbosely? Anyways, my  
two systems have their networking configured a la:

boxA:
bridge0
re0   10.1.0.1 connected to outside world
tap0  192.168.1.1/16 connected to bridge0

boxB:
bridge0
wm0   10.1.0.2 connected to outside world
tap0  192.168.2.1/16 connected to bridge0

Now I add the etherip interfaces:

boxA# ifconfig etherip0 create
boxA# ifconfig etherip0 192.168.1.2/16

boxB# ifconfig etherip0 create
boxB# ifconfig etherip0 192.168.2.2/16

boxA# ifconfig etherip0 192.168.1.2 tunnel 192.168.1.2 10.1.0.2
boxB# ifconfig etherip0 192.168.2.2 tunnel 192.168.2.2 10.1.0.1

and watch the two machines immediately enter into some sort of deadly  
embrace. They respond to a banging on the keyboard with about one  
keypress per five minutes. If I reset one system the other immediately  
wakes up.

So I realize that I'm not doing this the right way. But what IS the  
right way? Some enlightenment for tunnel newbies would be very much  
appreciated... preferably with a very complete example.

Regards,

Johan


-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.5 (Darwin)

iD8DBQFKkHjCKJmr+nqSTbYRAsfbAJ48w9MupdKMSrTTdw4mlqt5ZntRwwCgtNtk
BtxCBYqqbzB+1L50Vb/2IBc=
=gEk6
-----END PGP SIGNATURE-----