On 28.03.2014 09:33, Laine Stump wrote:
On 03/27/2014 07:17 PM, Michal Privoznik wrote:
We allow users to use SLIRP stack. However, there are some knobs which are not exposed to users, such as host network address, DNS server, smb, and others.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com> --- docs/formatdomain.html.in | 7 +- docs/schemas/domaincommon.rng | 23 +++++- src/conf/domain_conf.c | 88 ++++++++++++++++++++++ src/conf/domain_conf.h | 6 ++ src/qemu/qemu_command.c | 19 +++++ .../qemuxml2argvdata/qemuxml2argv-net-user-ip.args | 7 ++ .../qemuxml2argvdata/qemuxml2argv-net-user-ip.xml | 33 ++++++++ tests/qemuxml2argvtest.c | 1 + 8 files changed, 180 insertions(+), 4 deletions(-) create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-net-user-ip.args create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-net-user-ip.xml
It is essential that this new <ip> element be rejected, preferably at parse time in the qemu-specific post-parse callback, for any interface type that doesn't support it. Since it is the most obvious way of specifying an IP address for a guest (and it is a way that has been requested in the past) we are otherwise certain to have a lot of support questions asking why the IP address setting isn't being used.
Well, I think rejecting it goes against current policy 'silently ignore elements unknown to the libvirt'. But I can live with that here.
Also, the attribute names seem confusing. The "address" attribute is the address of the *network*, not of the interface, and "dhcpstart" is the address of the interface. Even though qemu specifies the network address and interface address separately, the network address is really pointless, as it can/should be derived from the interface address.
It is, so what XML schema do you propose? I'm not pleased with <ip/> either. But it was the best I could come up with so far. Maybe we are aiming for more structured XML here: <interface type='user'> <network address='192.168.2.0' prefix='24'/> <dns address='92.168.2.3'/> <dhcp start='192.168.2.9'/> <mac address='00:11:22:33:44:55'/> <model type='rtl8139'/> </interface> Or even more neting: <interface type='user'> <network> <ip address='192.168.2.0' prefix='24'/> <dns address='92.168.2.3'/> <dhcp start='192.168.2.9'/> </network> <mac address='00:11:22:33:44:55'/> <model type='rtl8139'/> </interface>
(I realize that "dhcpstart" isn't *exactly* the interface IP, since qemu allows for multiple IP leases to be acquired from it's internal dhcp server, but I think that usage is very rare, and unlikely to be possible for any other backend we might support).
Beyond that, a question not with your patch, but with qemu's implemenation - does it always assume that the gateway address is $network.1 ? If that's the case, then I think definitely we should just have <ip address='x' prefix='y'/>. If there is support for specifying the gateway address, then it should be named "gateway", as is already done in the network xml for static routes.
That's good question, but my qemu code base reading skills are just too weak to answer it. Michal