Re: [Qemu-devel] Re: [PATCH] Add pcap-based host network bridge

[Lennart Sorensen]

On Tue, May 12, 2009 at 06:34:04PM +0200, Jan Kiszka wrote:
> Lennart Sorensen wrote:
> > On Tue, May 12, 2009 at 10:23:43AM +0200, Jan Kiszka wrote:
> >> We basically dropped the idea as it turned out that - at least under
> >> Linux - there is no host<->guest link realizable with reasonable effort.
> > 
> > Has anyone ever looked at how vmware's vmnet does it?
> 
> Whatever they do (I bet it's nothing trivial): Everything that
> complicates the pcap-based approach beyond a certain level (roughly the
> one that is required for tap-based bridges) makes it unattractive. There
> are alternatives (except for ancient Win2k IIRC), pcap just appeared to
> be a cheap shortcut. But that turned out to be not true.

Not sure.  I just know with the vmware approache, the guest can be
bridged to the network in a way that allows the guest to talk to the
host as well as anything else on the external network, which to me is
by far the nicest setup.  I still haven't clued in to how to make vmware
talk to the host system and allow incoming connections on a real IP yet.
Guest to host works through 10.2.2.2 or something like that, but nothing
else ever has for me.  Maybe I just haven't managed to make sense of the
-net documentation to figure out which of the very many options would
do what I want.

Vmware's vmnet does look like a lot of code (somewhere near 400k) and
has some binary only code included, so who knows.  Certainly involves
bridging though.

-- 
Len Sorensen