Re: [Qemu-devel] Re: Network bridging without adding bridge with brctl, possible?

[Gerhard Wiesinger]

On Sun, 20 Feb 2011, Jan Kiszka wrote:

> On 2011-02-20 13:49, Gerhard Wiesinger wrote:
> > On Sun, 20 Feb 2011, Jan Kiszka wrote:
> >
> > > On 2011-02-19 20:32, Gerhard Wiesinger wrote:
> > > > Hello,
> > > http://virt.kernelnewbies.org/MacVTap
> > >
> > >    ip link add link eth1 name macvtap0 type macvtap mode bridge
> > >    ip link add link eth1 name macvlan0 type macvlan mode bridge
> > >    ifconfig macvlan0 ...
> >
> >
> > Hello Jan,
> >
> > iproute2 2.6.37 is needed!
> > http://devresources.linuxfoundation.org/dev/iproute2/download/iproute2-2.6.37.tar.bz2
> >
> > ==================================================================================
> >
> > 1.) Only macvtap interface used
> > ==================================================================================
> >
> > For me it was just unlogically to use a VLAN type interface. Therefore I
> > tried the following which worked nearly:
> > /root/download/iproute2/iproute2-2.6.37/ip/ip link add link eth0 name
> > macvtap0 type macvtap mode bridge
> > /root/download/iproute2/iproute2-2.6.37/ip/ip link set macvtap0 address
> > 1a:46:0b:ca:bc:7b up
> > ip link show macvtap0
> > ls -l /dev/tap*
> > # crw-rw---- 1 root root 249, 8 Feb 20 13:07 /dev/tap8
> > qemu-system-x86_64 ... some params ... -net
> > nic,model=e1000,macaddr=1a:46:0b:ca:bc:7b -net tap,fd=3 3<>/dev/tap8
> >
> > Booting Knoppix 6.2 with ping is ok, MAC address is also correct on
> > second host.
> >
> > Only problem is that from host to guest no networking is possible (only
> > from guest to other host).
> >
> > Any ideas? I guess some forwarding is missing? iptables forward missing?
>
> To my understanding macvlan(+macvtap) devices in bridge mode can only
> talk to the outer world via the physical device they are attached to or
> other macvlan nodes attached to that same device. Therefore...
>
> > ==================================================================================
> >
> > 2.) Only macvtap interface used
> > ==================================================================================
> >
> > /root/download/iproute2/iproute2-2.6.37/ip/ip link add link eth0 name
> > macvtap0 type macvtap mode bridge
> > /root/download/iproute2/iproute2-2.6.37/ip/ip link set macvtap0 address
> > 1a:46:0b:ca:bc:7b up
> > #/root/download/iproute2/iproute2-2.6.37/ip/ip link add link eth0 name
> > macvlan0 type macvlan mode bridge
> > #/root/download/iproute2/iproute2-2.6.37/ip/ip link set macvlan0 address
>
> ...the need for this additional macvlan device. You just have to set an
> IP on macvlan0.

Negative.

Tried:
/root/download/iproute2/iproute2-2.6.37/ip/ip link add link eth0 name macvtap0 
type macvtap mode bridge
/root/download/iproute2/iproute2-2.6.37/ip/ip link set macvtap0 address 
1a:46:0b:ca:bc:7b up
/root/download/iproute2/iproute2-2.6.37/ip/ip link add link eth0 name macvlan0 
type macvlan mode bridge
/root/download/iproute2/iproute2-2.6.37/ip/ip link set macvlan0 address 
1a:46:0b:ca:bc:7c up
ip link show macvtap0
ip link show macvlan0
ls -l /dev/tap*
# crw-rw---- 1 root root 249, 10 Feb 20 15:45 /dev/tap10
ifconfig macvlan0 192.168.0.23 up

DHCP is configure for 1a:46:0b:ca:bc:7b mac for 192.168.0.23 ip and 
1a:46:0b:ca:bc:7c mac for 192.168.0.24 ip.

# works without outer connection
qemu-system-x86_64 ... some params ... -net nic,model=e1000,macaddr=1a:46:0b:ca:bc:7b 
-net tap,fd=3 3<>/dev/tap10

# 2nd try:
ifconfig macvlan0 192.168.0.24 up
# No network at all
qemu-system-x86_64 ... some params ... -net nic,model=e1000,macaddr=1a:46:0b:ca:bc:7c 
-net tap,fd=3 3<>/dev/tap10

Seems to me quite logically because macvtap0 (and not macvlan0) is 
associated with /dev/tap10 but with another mac address set in KVM.

Any furher ideas?

Thnx.

Ciao,
Gerhard

--
http://www.wiesinger.com/