Manually specifying mac for tap device used by qemu

jb · 2010-03-12 23:39:26

I've followed the wiki entry on using tap networking and everything seems to be working fine. However, it seems that tap0 is given a random mac address every time its run, and the network this server is on uses a mac address white list to get an ip.

I tried adding to the 4th line in /etc/qemu-ifup so that it looked like this:

sudo /sbin/ifconfig $1 0.0.0.0 promisc up hw ether 00:26:B9:43:9C:06

but that just caused the error "SIOCSIFHWADDR: Device or resource busy". Has anyone accomplished this or know where it's possible to specify one?

Thanks.

jb · 2010-03-26 18:43:26

Not to post bump, but I found a solution to the initial problem; one that implies I'll need to make a qemu-ifup for each vm. Here's what I changed.

#!/bin/sh
#/etc/qemu-ifup
echo "Executing/etc/qemu-ifup"
echo "Bringing up $1 for bridged mode..."
sudo /sbin/ifconfig $1 hw ether 00:26:B9:43:9C:08
sudo /sbin/ifconfig $1 0.0.0.0 promisc up
echo "Adding $1 to br0..."
sudo /usr/sbin/brctl addif br0 $1
sleep 2

#!/bin/bash
#~/qemu-prototype
USERID=`whoami`
IFACE=`sudo tunctl -b -u $USERID`
qemu-kvm -net nic,macaddr=00:26:B9:43:9C:08 -net tap,ifname="$IFACE" -cpu kvm64 -m 512 -smp 2 -hda prototype.arch64.qcow2 -vnc :1
$*
sudo tunctl -d $IFACE # &> /dev/null

But now even with a white-listed mac address, I still can't get a network connection in the vm. And by that, I mean /etc/rc.d/network fails to get an IP, and dhcpcd just reports a timeout. Here's what the host's ifconfig output shows. Anyone know if this is what should look like (or if further info is needed to answer)?

[cave@aperture ~]$ ifconfig                                                                                                                                             
br0       Link encap:Ethernet  HWaddr 00:26:B9:43:9C:02                                                                                                                 
          inet addr:163.118.<snip />  Bcast:163.118.<snip /> Mask:255.255.255.0                                                                                            
          inet6 addr: fe80::226:b9ff:fe43:9c02/64 Scope:Link                                                                                                            
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1                                                                                                            
          RX packets:26126236 errors:0 dropped:0 overruns:0 frame:0                                                                                                     
          TX packets:8243 errors:0 dropped:0 overruns:0 carrier:0                                                                                                       
          collisions:0 txqueuelen:0                                                                                                                                     
          RX bytes:2005110288 (1912.2 Mb)  TX bytes:1968718 (1.8 Mb)                                                                                                    
                                                                                                                                                                        
eth0      Link encap:Ethernet  HWaddr 00:26:B9:43:9C:02                                                                                                                 
          inet6 addr: fe80::226:b9ff:fe43:9c02/64 Scope:Link                                                                                                            
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1                                                                                                            
          RX packets:26126530 errors:0 dropped:0 overruns:0 frame:0
          TX packets:8590 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:2475473294 (2360.7 Mb)  TX bytes:2049752 (1.9 Mb)
          Interrupt:36 Memory:da000000-da012800 

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:141 errors:0 dropped:0 overruns:0 frame:0
          TX packets:141 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:24816 (24.2 Kb)  TX bytes:24816 (24.2 Kb)

tap0      Link encap:Ethernet  HWaddr 00:26:B9:43:9C:08  
          inet6 addr: fe80::226:b9ff:fe43:9c08/64 Scope:Link
          UP BROADCAST RUNNING PROMISC MULTICAST  MTU:1500  Metric:1
          RX packets:12 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1391112 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:500 
          RX bytes:4104 (4.0 Kb)  TX bytes:125533941 (119.7 Mb)

Arch Linux

#1 2010-03-12 23:39:26

Manually specifying mac for tap device used by qemu

#2 2010-03-26 18:43:26

Re: Manually specifying mac for tap device used by qemu

Board footer