2002-09-05 22:08:05

by Shaya Potter

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Subject: virtual ethernet adapter?

Is there any open code that is similiar to what vmware provides that
enables one to create virtual ethernet adapters? I've seen the tap
device, but that's not what I need.

thanks,

shaya potter




2002-09-06 06:03:18

by Peter Svensson

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Subject: Re: virtual ethernet adapter?

On 5 Sep 2002, Shaya Potter wrote:

> Is there any open code that is similiar to what vmware provides that
> enables one to create virtual ethernet adapters? I've seen the tap
> device, but that's not what I need.

In what way is it not what you need? What do you need?

Peter
--
Peter Svensson ! Pgp key available by finger, fingerprint:
<[email protected]> ! 8A E9 20 98 C1 FF 43 E3 07 FD B9 0A 80 72 70 AF
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Remember, Luke, your source will be with you... always...


2002-09-06 12:33:36

by Shaya Potter

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Subject: Re: virtual ethernet adapter?

from what I can tell, tap just lets a programs use it, but one needs a
user space app behind it (reading and writing to it). It doesn't seem
to have the ability to live on the network like vmware's vmnet stuff
does, perhaps I'm wrong and was confused by the web page.

On Fri, 2002-09-06 at 02:07, Peter Svensson wrote:
> On 5 Sep 2002, Shaya Potter wrote:
>
> > Is there any open code that is similiar to what vmware provides that
> > enables one to create virtual ethernet adapters? I've seen the tap
> > device, but that's not what I need.
>
> In what way is it not what you need? What do you need?
>
> Peter
> --
> Peter Svensson ! Pgp key available by finger, fingerprint:
> <[email protected]> ! 8A E9 20 98 C1 FF 43 E3 07 FD B9 0A 80 72 70 AF
> ------------------------------------------------------------------------
> Remember, Luke, your source will be with you... always...
>


2002-09-06 12:49:22

by Peter Svensson

[permalink] [raw]
Subject: Re: virtual ethernet adapter?

On 6 Sep 2002, Shaya Potter wrote:

> from what I can tell, tap just lets a programs use it, but one needs a
> user space app behind it (reading and writing to it). It doesn't seem
> to have the ability to live on the network like vmware's vmnet stuff
> does, perhaps I'm wrong and was confused by the web page.

Well, you want at program to read and write ethernet frames, don't you? To
What happens is that the operating system sees the data written by the
program as coming in over a ethernet interface, a virtual one.

To connect that interface to a real one you use the bridging code. I think
it is standard in the newer kernels. Otherwise you can download it from
http://bridge.sourceforge.net/. Create a bridge and attach both the real
ethernet card and the virtual one to it and use the resulting interface
br0 (or whatever you choose to call it) instead of the normal ethernet
interface. Your program that is attached to the "tap" will now appear as
another computer on the same ethernet segment to both your computer and
all others attachet the the segment.

Peter
--
Peter Svensson ! Pgp key available by finger, fingerprint:
<[email protected]> ! 8A E9 20 98 C1 FF 43 E3 07 FD B9 0A 80 72 70 AF
------------------------------------------------------------------------
Remember, Luke, your source will be with you... always...


2002-09-06 20:47:53

by Shaya Potter

[permalink] [raw]
Subject: Re: virtual ethernet adapter?

On Fri, 2002-09-06 at 08:53, Peter Svensson wrote:
> On 6 Sep 2002, Shaya Potter wrote:
>
> > from what I can tell, tap just lets a programs use it, but one needs
a
> > user space app behind it (reading and writing to it). It doesn't
seem
> > to have the ability to live on the network like vmware's vmnet stuff
> > does, perhaps I'm wrong and was confused by the web page.
>
> Well, you want at program to read and write ethernet frames, don't
you? To
> What happens is that the operating system sees the data written by the
> program as coming in over a ethernet interface, a virtual one.
>
> To connect that interface to a real one you use the bridging code. I
think
> it is standard in the newer kernels. Otherwise you can download it
from
> http://bridge.sourceforge.net/. Create a bridge and attach both the
real
> ethernet card and the virtual one to it and use the resulting
interface
> br0 (or whatever you choose to call it) instead of the normal ethernet
> interface. Your program that is attached to the "tap" will now appear
as
> another computer on the same ethernet segment to both your computer
and
> all others attachet the the segment.

that actually sounds more promising, but does it still involves the
program attached to the tap outputting ethernet frames. i.e. I can't
make a virtual ethernet driver with my own rules, have netfilter bind a
process to just use that adapter, and then just run the process as
normal. or am I still understating the capabilities?

thanks,

shaya potter