Stefan, Thanks for reviewing.
Stefan Berger<stefanb@linux.vnet.ibm.com> wrote on 10/25/2011 04:59:16 AM:
I hope that this code will be able to support multiple IP addresses once my patches have gone in. I labelled in the code with comments the places that need to be revised (3, I believe) for multiple address support. I added one check to ignore an additional address when you already have one for an interface. The other depends on the form of multiple address support. If it is a mechanism that changes variable values (either add or remove) in place in the filters, it'll be reverting to code similar to my first post. If it uses something like virNWFilterInstantiateFilterLate(), my main concern is making sure there isn't a window while deleting or adding an address that rebuilds the entire filter where either no packets or spoofed packets would be allowed. This should not be possible to happen during this call. The new filter is built while the old filter is still active. The new filter is connected to the 'root' where all filters are connected to and only then
On 10/25/2011 02:01 PM, David Stevens wrote: the old one is disconnected and deleted. So the switch-over is 'atomic'. Though this *may* need re-visiting in case *all* leases expiring and IP = <empty> and one has to put in the DHCP-only filter now.
Both cases would need to remove the DHCP-only rule installation in delete, since removing one of multiple addresses shouldn't remove the other address(es)'s filters. The internal snooping code supports multiple addresses per interface as before. It assumes 1-interface==1-network as before, so your comments about VLANs and the leasefile also require a visit, but don't apply without multiple address support in the rest of nwfilter. Tracking and saving the VLAN ID or saving and matching the DHCP client ID should do that.
We'll get to that. Stefan
+-DLS