[ovs-discuss] filtering macs/ip

Matthew Law matt at webcontracts.co.uk
Thu May 13 19:36:47 UTC 2010


The post below is a question regarding xen cloud platform asked on the
xen-users list.  As this is also of interest to me, I thought I would ask
questions here and post any feedback to xen-users also.  I hope you don't
mind.

Is there any way currently (or planned for later) to persist flows
indefinitely?

And the point about "They are not associated with vm migration process":
is it not the case that the port being virtual could go with the vm to
another physical host in the vswitch?

Sorry if my questions are dumb!

Thanks,

Matt.

On Tue, May 11, 2010 9:47 am, George Shuklin wrote:
> I look deeper in openswitch... I found no way to have nice spoofing
> protection without openflow controller. And yes, spoofing is possible, I
> check it.
>
> Following lines to ovs-ofctl enables mac security (drop any traffic from
> VM with incorrect combination of MAC address and IP, settings work only
> for certain MAC/IP):
>
> ovs-ofctl add-flow xenbr0 "dl_src=36:75:e2:35:d7:ea priority=39000
> dl_type=0x0800 nw_src=18.93.16.25 idle_timeout=65000 action=normal"
> ovs-ofctl add-flow xenbr0 "dl_src=36:75:e2:35:d7:ea priority=38000
> dl_type=0x0800 nw_src=ANY idle_timeout=65000 action=drop"
>
>
> And we can bind mac to interface (port security):
>
> ovs-ofctl add-flow xenbr0 "in_port=2 priority=39000 dl_type=0x0800
> nw_src=188.93.16.253 idle_timeout=65000 action=normal"
> ovs-ofctl add-flow xenbr0 "in_port=2 priority=38500 dl_type=0x0806
> idle_timeout=65000 action=normal" #ÐÏËÁ ÐÕÓËÁÅÍ ARP ÂÅÚ ËÏÎÔÒÏÌÑ.
> ovs-ofctl add-flow xenbr0 "in_port=2 priority=38000 idle_timeout=65000
> action=drop"
>
> The main problems I see here is:
> 1) Those line washed away after idle_timeout.
> 2) They are not associated with vm migration process
> 3) Port number hard to obtain (about 3 greps from xe/ovs output).
>
>
> I still did not tried to install/use openflow controller (may be this will
> be gold solution?), but direct control of openflow for OVS is very tricky
> and may cause some unpleasant results in product environment.





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