Re: TCP/IP with virtual device dsn0 experience?

Nathan Bryant (
Thu, 27 Feb 1997 18:06:46 -0500 (EST)

On Thu, 27 Feb 1997, Alan Cox wrote:

> > kernel interfaces, but discovered the the kernel's higher-level network
> > code had changed such that only one application at a time could open a
> > SOCK_PACKET for any specific socket type, which prevented the whole scheme
> > from working.
> It isnt supposed to have been. Are you sure about this ?

Yeah, fairly certain. I read through the relevant kernel code at the time,
and that was my interpretation of what I saw. I don't *think* I was
wrong... ;) If I'm right I guess it would have to be classified as a bug.

> > Has this behaviour of SOCK_PACKET changed since circa 1.3.70? If so,
> > dosnet.c could be modified to work with new kernels. (Of course, if
> > somebody's already done this I may be flapping my jaw needlessly. :)
> Its changed a bit in that you can bind() them and pass protocol id hints
> when you want (eg for PPP)

Sounds interesting. I know you can run multiple DOSemu's with TCP/IP, with
the standard packet driver, if you are on an ethernet and you give each
DOS box a different IP number and you disable forwarding to those
addresses. Does this also work over PPP, if your provider assigns you a
block of addresses?

The 'dsn0' device was a nice idea, even if its interface to userland was a
nasty hack. Getting it to work in recent kernels would allow us to combine
it with masquerading.

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