On 03/22/2013 12:57 PM, Paolo Bonzini wrote:
Linux uses the lowest enslaved MAC address as the MAC address of
the bridge. Set MAC address to a high value so that it does not
affect the MAC address of the bridge.
Changing the MAC address of the bridge could cause a few seconds
of network downtime.
Cc: qemu-sta...@nongnu.org
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
---
qemu-bridge-helper.c | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff --git a/qemu-bridge-helper.c b/qemu-bridge-helper.c
index 287bfd5..6a0974e 100644
--- a/qemu-bridge-helper.c
+++ b/qemu-bridge-helper.c
@@ -367,6 +367,24 @@ int main(int argc, char **argv)
goto cleanup;
}
+ /* Linux uses the lowest enslaved MAC address as the MAC address of
+ * the bridge. Set MAC address to a high value so that it doesn't
+ * affect the MAC address of the bridge.
+ */
+ if (ioctl(ctlfd, SIOCGIFHWADDR, &ifr) < 0) {
+ fprintf(stderr, "failed to get MAC address of device `%s': %s\n",
+ iface, strerror(errno));
+ ret = EXIT_FAILURE;
+ goto cleanup;
+ }
+ ifr.ifr_hwaddr.sa_data[0] = 0xFE;
+ if (ioctl(ctlfd, SIOCSIFHWADDR, &ifr) < 0) {
+ fprintf(stderr, "failed to set MAC address of device `%s': %s\n",
+ iface, strerror(errno));
+ ret = EXIT_FAILURE;
+ goto cleanup;
+ }
+
/* add the interface to the bridge */
prep_ifreq(&ifr, bridge);
ifindex = if_nametoindex(iface);
Is it desirable to change a mac address under the covers? I know you
mentioned that libvirt does something like this already.
Also it seems like this might be better if it was optional.
qemu-bridge-helper can take command line options like this:
-net tap,helper="/usr/local/libexec/qemu-bridge-helper --br=br0"
Perhaps adding a --macaddr option is a better approach?
--
Regards,
Corey Bryant
