nat does not work with hvm

[Erdem Bayer <ebayer@ttnet.net.tr>]

Hello all

I am using open source xen v 3.0.4. When network-nat and vif-nat is 
activated in the config file, modified guests boot ok but hvm guests 
does not have network connection. Here is the config files:

xend-config.sxp
-------------------------------------
#(network-script network-bridge)
#(vif-script vif-bridge)

(network-script network-nat)
(vif-script vif-nat)

-------------------------------------
I have commented the following lines from qemu-ifup script as I don't 
want to use bridge.
-------------------------------------
#ifconfig $1 0.0.0.0 up
#brctl addif $2 $1
-------------------------------------
I have also try commenting only the second line from the script. Still 
no luck. In that case an interface named tap is created also.

And the config file for the domain:
-------------------------------------
import os, re
arch = os.uname()[4]
if re.search('64', arch):
   arch_libdir = 'lib64'
else:
   arch_libdir = 'lib'
kernel = "/usr/lib/xen/boot/hvmloader"
builder='hvm'
memory = 512
shadow_memory = 8
name = "winxp"
acpi=0
vif = [ 'ip=192.168.3.1, mac=aa:00:00:50:02:f0, type=ioemu, 
model=rtl8139' ]
disk = [ 'file:/mnt/sda5/xen/images/winxp1.img,hda,w',
'phy:/dev/cdrom,hdb:cdrom,r' ]
device_model = '/usr/' + arch_libdir + '/xen/bin/qemu-dm'
sdl=1
vnc=0
vncpasswd=''
stdvga=0
serial='pty'
-------------------------------------

When this domain is booted, it boots ok. Here is the network-nat status 
output.
============================================================
eth0      Link encap:Ethernet  HWaddr 00:17:08:37:F1:B7
         inet addr:10.0.0.5  Bcast:10.255.255.255  Mask:255.0.0.0
         UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
         RX packets:30 errors:0 dropped:0 overruns:0 frame:0
         TX packets:20 errors:0 dropped:0 overruns:0 carrier:0
         collisions:0 txqueuelen:1000
         RX bytes:4530 (4.4 Kb)  TX bytes:2217 (2.1 Kb)
         Interrupt:20

lo        Link encap:Local Loopback
         inet addr:127.0.0.1  Mask:255.0.0.0
         UP LOOPBACK RUNNING  MTU:16436  Metric:1
         RX packets:6 errors:0 dropped:0 overruns:0 frame:0
         TX packets:6 errors:0 dropped:0 overruns:0 carrier:0
         collisions:0 txqueuelen:0
         RX bytes:328 (328.0 b)  TX bytes:328 (328.0 b)

vif1.0    Link encap:Ethernet  HWaddr FE:FF:FF:FF:FF:FF
         inet addr:192.168.3.128  Bcast:0.0.0.0  Mask:255.255.255.255
         UP BROADCAST MULTICAST  MTU:1500  Metric:1
         RX packets:0 errors:0 dropped:0 overruns:0 frame:0
         TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
         collisions:0 txqueuelen:32
         RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)


192.168.3.1 dev vif1.0  scope link  src 192.168.3.128
10.0.0.0/8 dev eth0  proto kernel  scope link  src 10.0.0.5
127.0.0.0/8 via 127.0.0.1 dev lo  scope link
default via 10.0.0.2 dev eth0

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use 
Iface
192.168.3.1     0.0.0.0         255.255.255.255 UH    0      0        0 
vif1.0
10.0.0.0        0.0.0.0         255.0.0.0       U     0      0        0 
eth0
127.0.0.0       127.0.0.1       255.0.0.0       UG    0      0        0 lo
0.0.0.0         10.0.0.2        0.0.0.0         UG    0      0        0 
eth0
============================================================

When this domain is booted, it cannot connect anywhere. It can not even 
ping 192.168.3.128 !!!!
And when the dom0 pings 192.168.3.1 Destination host unreachable error 
is get. The tcpdump in dom0 does not show any packets flowing.

I have tried the same config with an ubuntu dapper hvm guest and still 
no connections.
But when a modified guest is booted with the same network config, there 
is no problem. Everyone can ping each other and domU does have an 
internet connection. Here is the network-nat status output of the 
modified guest.

============================================================
eth0      Link encap:Ethernet  HWaddr 00:17:08:37:F1:B7
          inet addr:10.0.0.5  Bcast:10.255.255.255  Mask:255.0.0.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:1706 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1546 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:1333224 (1.2 Mb)  TX bytes:159280 (155.5 Kb)
          Interrupt:20

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:9 errors:0 dropped:0 overruns:0 frame:0
          TX packets:9 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:500 (500.0 b)  TX bytes:500 (500.0 b)

vif10.0   Link encap:Ethernet  HWaddr FE:FF:FF:FF:FF:FF
          inet addr:192.168.3.128  Bcast:0.0.0.0  Mask:255.255.255.255
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:18 errors:0 dropped:0 overruns:0 frame:0
          TX packets:28 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:32
          RX bytes:1242 (1.2 Kb)  TX bytes:3118 (3.0 Kb)


192.168.3.1 dev vif10.0  scope link  src 192.168.3.128
10.0.0.0/8 dev eth0  proto kernel  scope link  src 10.0.0.5
127.0.0.0/8 via 127.0.0.1 dev lo  scope link
default via 10.0.0.2 dev eth0

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use 
Iface
192.168.3.1     0.0.0.0         255.255.255.255 UH    0      0        0 
vif10.0
10.0.0.0        0.0.0.0         255.0.0.0       U     0      0        0 eth0
127.0.0.0       127.0.0.1       255.0.0.0       UG    0      0        0 lo
0.0.0.0         10.0.0.2        0.0.0.0         UG    0      0        0 eth0
============================================================


I have also tried dhcp instead of statically giving an ip address. Still 
the modified guest takes an ip address and have network, the hvm guest 
can not even reach the dhcp server in dom0.

Any ideas?
Erdem