[ovs-discuss] IP address wildcard mask do not follow openflow 1.0 spec

[Justin Pettit]

If you're concerned/confused about what's going on the wire, please fire up wireshark and take a look.  You're giving human-readable ovs-ofctl commands on the command-line, which it is translating into OpenFlow commands on the wire.  We think CIDR masks are more intuitive to deal with than the strange encoding OpenFlow uses (which we originally defined, by the way).  If you put /24 on the CLI, it will go out on the wire with the OpenFlow encoding that you're expecting.

--Justin


On Jan 30, 2012, at 11:33 PM, edward wilson wrote:

> hi
> yes as per openvswitch we should use the metric /24 for the mask 255.255.255.0 to cover IPv4
> 10.1.3.0 to 10.1.3.255 for a wildcard of 10.1.3.*."
> 
> but in openflow 1.0 spec following is written
> 
> The source and destination netmasks for IP addresses are each specified with a 6-bit number
> in the wildcard description. It is interpreted similar to the CIDR suffix, but
> with the opposite meaning, since this is being used to indicate which bits in the
> IP address should be treated as “wild”. For example, a CIDR suffix of ”24”
> means to use a netmask of “255.255.255.0”. However, a wildcard mask value of
> “24” means that the least-significant 24-bits are wild, so it forms a netmask of
> “255.0.0.0”.
> 
> so openflow 1.0 spec say /24 means 255.0.0.0 but in openvswitch it means 255.255.255.0
> 
> regards
> 
> 
> 
> On Fri, Jan 27, 2012 at 9:53 PM, Iben Rodriguez <iben.rodriguez at gmail.com> wrote:
> Hi Ed,
> 
> What do you mean wildcarded? is that like a * ? This might be a semantics issue.
> 
> Could you be confusing metric with significant bits of a mask...?
> 
> /8 is a metric that would use the mask 255.0.0.0 to cover IPv4
> addresses from 10.0.0.0 to 10.255.255.255 - that might mean a wildcard
> of 10.*.*.*
> 
> You should use the metric /24 for the mask 255.255.255.0 to cover IPv4
> 10.1.3.0 to 10.1.3.255 for a wildcard of 10.1.3.*.
> 
> 
> I b e n
> +14087824726
> Skype: ibenrodriguez
> 
> 
> 
> On Fri, Jan 27, 2012 at 2:48 AM, edward wilson
> <edward.wilson2601 at gmail.com> wrote:
> >
> > hi,
> >
> > Actually the issue is according to openflow 1.0 spec when i use
> > ovs-ofctl add-flows br0 "dl_type=0x0800 nw_proto=1 nw_dst=10.0.3.4
> > nw_src=10.1.3.2/8 actions=1"
> >
> > ovs-dump-flows br0 should give follwing output
> >
> > cookie=0x0, duration=21.265s, table=0, n_packets=0, n_bytes=0,
> > icmp,nw_src=10.0.3.4,nw_dst=10.1.3.0/8 actions=output:1
> >
> > that is the least significant  8 bits should be wildcarded.
> >
> > But in openvswitch the ovs-dump-flows br0 give me following output
> >
> > cookie=0x0, duration=21.265s, table=0, n_packets=0, n_bytes=0,
> > icmp,nw_src=10.0.3.4,nw_dst=10.0.0.0/8 actions=output:1
> >
> > this means least significant 24 bits are wildcarded.
> >
> > In openvswitch code it is shown that CIDR masks are supported for IP
> > address, which is not openflow 1.0 compliant.
> >
> > I get the same result when i  look at output of ovs-ofctl specking openflow.
> >
> >
> > On Fri, Jan 27, 2012 at 3:21 PM, Justin Pettit <jpettit at nicira.com> wrote:
> >>
> >> I don't think there's a problem.  I'd guess if you looked at the output of
> >> ovs-ofctl speaking OpenFlow, you'd see the mask as defined in the spec.
> >>  However, we've made the user interface more intuitive to users, so it uses
> >> normal CIDR masks.
> >>
> >> --Justin
> >>
> >>
> >> On Jan 27, 2012, at 1:11 AM, edward wilson wrote:
> >>
> >> > HI,
> >> > I am using openvswitch 1.2.2 on my linux 2.6.38 fedora machine.
> >> > I added following flow on switch
> >> >
> >> > ovs-ofctl add-flows br0 "dl_type=0x0800 nw_proto=1 nw_dst=10.0.3.4
> >> > nw_src=10.1.3.2/8 actions=1"
> >> >
> >> > Now when i use ovs-ofctl dump-flows br1, it shows
> >> >
> >> >  cookie=0x0, duration=3.855s, table=0, n_packets=0, n_bytes=0,
> >> > icmp,nw_dst=10.0.3.4,nw_src=10.0.0.0/8 actions=NORMAL
> >> >
> >> >
> >> > Now openvswitch interpret this wildcard mask as CIDR suffix, and it has
> >> > wildcarded 24 least significant bits, first 8 bits are non-wildcard
> >> > But as per openflow 1.0 spec wildcard mask is interpreted as CIDR suffix
> >> > with opposite meaning , i.e suffix of 8 should wildcard least significant 8
> >> > bits of ip address.
> >> >
> >> >
> >> >
> >> >
> >> >
> >> > _______________________________________________
> >> > discuss mailing list
> >> > discuss at openvswitch.org
> >> > http://openvswitch.org/mailman/listinfo/discuss
> >>
> >
> >
> > _______________________________________________
> > discuss mailing list
> > discuss at openvswitch.org
> > http://openvswitch.org/mailman/listinfo/discuss
> >
>