[Bridge] eth1394 interface support?

[Bridge] eth1394 interface support?

[Yuval Kogman]

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I have a linux box which sits in the living room and plays
ti^H^Hfreevo.

Among other things it also talks to the cable modem via interface
eth0, and does NAT transformations for eth1.

Yesterday i was sitting in the living room with my laptop, thinking
about the fact that my wireless access point will only arrive next
week, and then remembered they both the laptop and the linux boxhave
firewire. The plot thickens.

I enabled bridging support in the kernel, and i got to

	brctl addbr br0
	brctl addif br0 eth1 # LAN interface
	brctl addif br0 eth2 # firewire interface
	br_add_interface: Invalid argument

I reckon eth1394 is at fault, but I'd like to know what the bridge
code expects from it.

eth1394 on a different subnet works, and I can also manipulate the
routing table in funny ways. I'd like to not do that.

Thanks

-- 
 ()  Yuval Kogman <nothingmuch@woobling.org> 0xEBD27418  perl hacker &
 /\  kung foo master: /me sneaks up from another MIME part: neeyah!!!!!


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Re: [Bridge] eth1394 interface support?

[Stephen Hemminger]

On Wed, 11 Aug 2004 18:16:31 +0300
Yuval Kogman <nothingmuch@woobling.org> wrote:

> I have a linux box which sits in the living room and plays
> ti^H^Hfreevo.
> 
> Among other things it also talks to the cable modem via interface
> eth0, and does NAT transformations for eth1.
> 
> Yesterday i was sitting in the living room with my laptop, thinking
> about the fact that my wireless access point will only arrive next
> week, and then remembered they both the laptop and the linux boxhave
> firewire. The plot thickens.
> 
> I enabled bridging support in the kernel, and i got to
> 
> 	brctl addbr br0
> 	brctl addif br0 eth1 # LAN interface
> 	brctl addif br0 eth2 # firewire interface
> 	br_add_interface: Invalid argument
> 
> I reckon eth1394 is at fault, but I'd like to know what the bridge
> code expects from it.

It must use ethernet link encapsulation: 6 byte dst, 6 byte src, 2 byte type.
But 1394 uses 8 byte dst, 2 byte type.  Obviously this can't be bridged.


The bridge checks this by looking at the device type (dev->type) to
check if it is ARPHD_ETHER.  For 1394 this is set to ARPHRD_IEEE1394.

Re: [Bridge] eth1394 interface support?

[Yuval Kogman]

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On Wed, Aug 11, 2004 at 09:28:51 -0700, Stephen Hemminger wrote:
> It must use ethernet link encapsulation: 6 byte dst, 6 byte src, 2 byte type.
> But 1394 uses 8 byte dst, 2 byte type.  Obviously this can't be bridged.

Ah.. So, if I understand correctly, ethernet like behavior is in
effect emulated with firewire "messages", instead of firewire
completely encapsulating ethernet frames?

I always reckoned that the arp protocol over firewire contains some
sort of translation from the firewire addressing to an ethernet like
addressing scheme, and that host addresses are provided for by
address allocation faries.

Come to think of it, now that I'm looking, the fw based interfaces
don't have a MAC address [of the type i'm familiar with], instead
the hardware address is 8 bytes on OSX, and 16 with the bottom half
all zeros on linux.

*sigh*. It could have been fun.

Thanks for your knowlege and input!

-- 
 ()  Yuval Kogman <nothingmuch@woobling.org> 0xEBD27418  perl hacker &
 /\  kung foo master: /me spreads pj3Ar using 0wnage: neeyah!!!!!!!!!!!


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Re: [Bridge] eth1394 interface support?

[Chris Shaw]

I shudder at the thought.... but... if you want bridging between 1394 and
Ethernet or wireless interfaces, you can do it in W2K3 or WinXP...

Again I know.... gross... but it works if you can stand windows...

You can also use ProxyARP which is a kludge but it can work, provided that
1394 under linux can do ARP in the usual 802 way...

P.S. I don't know if this has been brought up and please don't take it as a
demand for features, just a query, but has support for bridging disparate
interface types been considered or attempted?

True hardware bridges/switches can bridge between wired/wireless,
tokenring/Ethernet FDDI/Ethernet HIPPI/Ethernet, etc etc etc... It would be
cool if linux could do it for the firewalling capabilities and because
hardware like that can be very expensive...

Does anyone know how windows is doing it? Is it more of a ProxyARP than a
bridge?

    -Chris

----- Original Message -----
From: "Stephen Hemminger" <shemminger@osdl.org>
To: "Yuval Kogman" <nothingmuch@woobling.org>
Cc: <bridge@lists.osdl.org>
Sent: Wednesday, August 11, 2004 9:28 AM
Subject: Re: [Bridge] eth1394 interface support?


> On Wed, 11 Aug 2004 18:16:31 +0300
> Yuval Kogman <nothingmuch@woobling.org> wrote:
>
> > I have a linux box which sits in the living room and plays
> > ti^H^Hfreevo.
> >
> > Among other things it also talks to the cable modem via interface
> > eth0, and does NAT transformations for eth1.
> >
> > Yesterday i was sitting in the living room with my laptop, thinking
> > about the fact that my wireless access point will only arrive next
> > week, and then remembered they both the laptop and the linux boxhave
> > firewire. The plot thickens.
> >
> > I enabled bridging support in the kernel, and i got to
> >
> > brctl addbr br0
> > brctl addif br0 eth1 # LAN interface
> > brctl addif br0 eth2 # firewire interface
> > br_add_interface: Invalid argument
> >
> > I reckon eth1394 is at fault, but I'd like to know what the bridge
> > code expects from it.
>
> It must use ethernet link encapsulation: 6 byte dst, 6 byte src, 2 byte
type.
> But 1394 uses 8 byte dst, 2 byte type.  Obviously this can't be bridged.
>
>
> The bridge checks this by looking at the device type (dev->type) to
> check if it is ARPHD_ETHER.  For 1394 this is set to ARPHRD_IEEE1394.
>


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Re: [Bridge] eth1394 interface support?

[Yuval Kogman]

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On Wed, Aug 11, 2004 at 13:48:17 -0700, Chris Shaw wrote:
> I shudder at the thought.... but... if you want bridging between 1394 and
> Ethernet or wireless interfaces, you can do it in W2K3 or WinXP...

Sadly.. ehm. ^UI don't have windows.

=D

At first it occured to me that maybe some sort of NAT for mac
addresses may be implemented, but then I read your message that said

> You can also use ProxyARP which is a kludge but it can work, provided that
> 1394 under linux can do ARP in the usual 802 way...

Well, that just worked... Funky!

Now if i can only get routing to work "automatically"... Right now
that means messing with the host that forwards, adding specific
hosts to the firewire interface (because it's easier than the other
way), and flushing temporary routes on other hosts.

Maybe some scripting is in order, with unsolicitated arp happenning
for clients which join the firewire subnet, but it's late and i
don't want to get into another war right now.

> True hardware bridges/switches can bridge between wired/wireless,
> tokenring/Ethernet FDDI/Ethernet HIPPI/Ethernet, etc etc etc... It would be
> cool if linux could do it for the firewalling capabilities and because
> hardware like that can be very expensive...

-- 
 ()  Yuval Kogman <nothingmuch@woobling.org> 0xEBD27418  perl hacker &
 /\  kung foo master: MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM: neeyah!


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Re: [Bridge] eth1394 interface support?

[Chris Shaw]

On Wed, Aug 11, 2004 at 13:48:17 -0700, Chris Shaw wrote:
> I shudder at the thought.... but... if you want bridging between 1394 and
> Ethernet or wireless interfaces, you can do it in W2K3 or WinXP...

Sadly.. ehm.I don't have windows.

=D

At first it occured to me that maybe some sort of NAT for mac
addresses may be implemented, but then I read your message that said

> You can also use ProxyARP which is a kludge but it can work, provided that
> 1394 under linux can do ARP in the usual 802 way...

Well, that just worked... Funky!

Now if i can only get routing to work "automatically"... Right now
that means messing with the host that forwards, adding specific
hosts to the firewire interface (because it's easier than the other
way), and flushing temporary routes on other hosts.

Maybe some scripting is in order, with unsolicitated arp happenning
for clients which join the firewire subnet, but it's late and i
don't want to get into another war right now.

> True hardware bridges/switches can bridge between wired/wireless,
> tokenring/Ethernet FDDI/Ethernet HIPPI/Ethernet, etc etc etc... It would
be
> cool if linux could do it for the firewalling capabilities and because
> hardware like that can be very expensive...

Check out a project called parprouted, it's a ProxyArp daemon that
automagically updates your ARP entries for you by using ARP queries from
other hosts! :)

    -Chris