qemu Hurd tun/tap networking with bridge on Fedora host

[Shakthi Kannan]

Hi,

I am trying to run Debian GNU Hurd (K16) on qemu (with kqemu) with
tun/tap, bridge setup from the host system (Fedora 11).

# rpm -qa | grep qemu
qemu-user-0.10.6-5.fc11.i586
qemu-system-arm-0.10.6-5.fc11.i586
kmod-kqemu-2.6.29.6-213.fc11.i586-1.4.0-0.2.pre1.fc11.11.i586
qemu-common-0.10.6-5.fc11.i586
qemu-system-ppc-0.10.6-5.fc11.i586
kqemu-1.4.0-0.4.pre1.fc11.noarch
qemu-system-mips-0.10.6-5.fc11.i586
qemu-0.10.6-5.fc11.i586
qemu-system-sparc-0.10.6-5.fc11.i586
qemu-system-sh4-0.10.6-5.fc11.i586
qemu-img-0.10.6-5.fc11.i586
qemu-system-m68k-0.10.6-5.fc11.i586
qemu-system-cris-0.10.6-5.fc11.i586
qemu-system-x86-0.10.6-5.fc11.i586

1. I have first stopped the NetworkManager on the host system to not
interfere with the configurations.

  # service NetworkManager stop

2. /etc/sysconfig/network-scripts/ files:

=== ifcfg-eth0 ===

# Networking Interface
DEVICE=eth0
TYPE=Ethernet
BRIDGE=br0
ONBOOT=yes

=== ifcfg-br0 ===

# Networking Interface
DEVICE=br0
ONBOOT=yes
HWADDR=00:21:70:CB:08:5D
TYPE=Bridge
BOOTPROTO=dhcp
DELAY=0
NAME="System br0"
UUID=5fb06bd0-0bb0-7ffb-45f1-d6edd65f3e03
STP=off

3. Start the network manually using:

  # service network restart

4. ifconfig outputs:

# ifconfig eth0
eth0      Link encap:Ethernet  HWaddr 00:21:70:CB:08:5D
          inet6 addr: fe80::221:70ff:fecb:85d/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:8642 errors:0 dropped:0 overruns:0 frame:0
          TX packets:4354 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:3611804 (3.4 MiB)  TX bytes:775071 (756.9 KiB)
          Interrupt:30 Base address:0x8000

br0       Link encap:Ethernet  HWaddr 00:21:70:CB:08:5D
          inet addr:<public-IP>  Bcast:<public-IP>..255  Mask:255.255.255.0
          inet6 addr: fe80::221:70ff:fecb:85d/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:1689 errors:0 dropped:0 overruns:0 frame:0
          TX packets:846 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:635269 (620.3 KiB)  TX bytes:191003 (186.5 KiB)

Ping works for any Internet IP address.

4. I have qemu-{ifup,ifdown} scripts:

=== qemu-ifup ===

#!/bin/sh
/usr/sbin/openvpn --mktun --dev $1 --user shaks
/sbin/ifconfig $1 172.16.0.1 promisc up
/usr/sbin/brctl addif br0 $1

=== qemu-ifdown ===

#!/bin/sh
/sbin/ifconfig $1 down
/usr/sbin/brctl delif br0 $1
/usr/sbin/openvpn --rmtun --dev $1

that create tap0 interface. I have "tun" module loaded.

# lsmod | grep tun
tun                     9852  1
tunnel4                 2672  1 sit

kvm module is not loaded. kqemu is loaded though.

5. Running qemu-ifup:

  # qemu-ifup tap0

creates the tap0 interface:

tap0      Link encap:Ethernet  HWaddr 6A:27:36:72:86:8B
          inet addr:172.16.0.1  Bcast:172.16.255.255  Mask:255.255.0.0
          inet6 addr: fe80::6827:36ff:fe72:868b/64 Scope:Link
          UP BROADCAST RUNNING PROMISC MULTICAST  MTU:1500  Metric:1
          RX packets:10 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1565 errors:0 dropped:329 overruns:0 carrier:0
          collisions:0 txqueuelen:100
          RX bytes:714 (714.0 b)  TX bytes:144683 (141.2 KiB)

# brctl show
bridge name     bridge id               STP enabled     interfaces
br0             8000.002170cb085d       no              eth0
                                                        tap0
pan0            8000.000000000000       no              

I do get a 169.254.0.0 entry for br0, which I remove using:

  # ip route del 169.254.0.0/16 dev br0

The route table looks like:

  # route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
<public-IP>.0   0.0.0.0         255.255.255.0   U     0      0        0 br0
172.16.0.0      0.0.0.0         255.255.0.0     U     0      0        0 tap0
0.0.0.0         <public-IP>.1   0.0.0.0         UG    0      0        0 br0

6. I boot Hurd on qemu using:

# qemu -boot a -hda hurd-16.img -fda grub-0.97-i386-pc.ext2fs -net nic
-net tap,ifname=tap0,script=no

I configure network using:

  # settrans -fgap /servers/socket/2 /hurd/pfinet -i eth0 -a
172.16.0.2 -g 172.16.0.1 -m 255.255.0.0
  # echo "nameserver 208.67.220.220" > /etc/resolv.conf

What works:
1. Ping to Internet from host system.
2. Pinging 172.16.0.1 (localhost) on host system.
3. Pinging 172.16.0.2 (on GNU Hurd), within qemu.

What doesn't work;
4. Pinging 172.16.0.1 to 172.16.0.2.

What could I be missing here? Appreciate any inputs. Thanks!

SK

-- 
Shakthi Kannan
http://www.shakthimaan.com