Re: [9fans] Re: booting a terminal in qemu

[Bakul Shah <bakul+plan9@bitblocks.com>]

> This should work as far as Plan 9 is concerned.
> It's qemu that is troublesome.  One possible approach
> to debugging is to boot the live (install) CD and then
> run ip/ipconfig -g 10.0.2.2 ether /net/ether0 10.0.2.15 255.255.255.0
> and see if that's enough to get a working network (i.e.,
> can you ping or telnet to port 567 or 9fs the remote machine).

In "qemu -net user" mode there are all sorts of restrictions
as qemu emulates the network layer + some userful services.
In particular all connections must be initiated from the VM
and ping won't work except to the port emulated by qemu.
Though, telnet from the VM should should work.  if a p9
terminal needs to `listen' on a port, -net user won't work.

> I have this script as my /etc/qemu-ifup, though I can't
> remember exactly why it is needed:
> 
> #!/bin/sh
> sudo -p "Password for $0:" /sbin/ifconfig $1 172.20.0.1

When you use -net tap, this script sets IP address for the
host side of the tap interface.  Packets pushed on this
interface pop up in corresponding /dev/tapN device (to be
read by qemu) and vice versa.

A more useful thing to do is to bridge the tap interface to
host's physical interface (or the host has to be a router and
provide other necessary things in your enviroments, such as
dhcp daemon or relay etc.).  Under FreeBSD-6 or later you can
have qemu-ifup do something like

#!/bin/sh
sudo sh -c "/sbin/ifconfig $1 up; /sbin/ifconfig bridge0 addm $1"

You don't need to give either bridge0 or the tap device any
IP address.  Prior to invoking qemu run the following and
also add these lines to /etc/rc.local.

/sbin/ifconfig bridge0 create
/sbin/ifconfig bridge0 addm em0 up

Replace em0 with your machine's real ethernet interface name.
If you want to run more than one qemu instance on the same
machine, you will need to specify mac addresses for
additional instances.

I imagine similar instructions exist for a linux/windows/mac hosts.