Thanks for figuring this out!

I guess that we can drop this patch, then.  (Let me know if you still
want it.)

On Thu, Jul 02, 2015 at 12:13:25AM +0000, Alin Serdean wrote:
> Sorry was relocating home.
> 
> Thanks for raising the question, it made me realize another problem :)
> 
> To answer your question directly: no this patch just ignores the attribute 
> completely it does not do any additional operations.
> 
> I introduced the attribute because it was failing at 
> https://github.com/openvswitch/ovs/blob/master/datapath-windows/ovsext/User.c#L341,
>  and to be more direct because the optional parameter was zero but apparently 
> this is just the symptom.
> 
> Due to your question I relooked over the code and found the actual problem: 
> when we are calling NlAttrParse we are calling it with array size of the 
> __OVS_PACKET_ATTR_MAX(the one defined in openvswitch.h) when we should call 
> it with the array size of the policy itself.
> 
> I will look over the windows datapath code to see if we slipped in that 
> mistake in other parts as well and will try to send the patches asap.
> 
> Regarding the patch it is semi dead weight because it just introduces the 
> attribute but no real logic is behind (it will work with and without it).
> 
> Alin.
> 
> -----Mesaj original-----
> De la: Ben Pfaff [mailto:[email protected]] 
> Trimis: Thursday, July 2, 2015 2:36 AM
> Către: Eitan Eliahu
> Cc: Alin Serdean; [email protected]
> Subiect: Re: [ovs-dev] [PATCH] datapath-windows: OVS_PACKET_ATTR_PROBE
> 
> Alin?
> 
> On Wed, Jul 01, 2015 at 11:04:57PM +0000, Eitan Eliahu wrote:
> > Hi Ben,
> > In general it doesn't seem that if the datapath does not support an 
> > attribute it would fail. (In other words the parsing validation code will 
> > not fail if an attribute is not included in the policy array).
> > I am not sure if the addition of this specific attribute to the policy 
> > masks an issue or not.
> > Perhaps Alin can tell.
> > Thanks,
> > Eitan
> > 
> > -----Original Message-----
> > From: dev [mailto:[email protected]] On Behalf Of Ben Pfaff
> > Sent: Wednesday, July 01, 2015 2:53 PM
> > To: Alin Serdean
> > Cc: [email protected]
> > Subject: Re: [ovs-dev] [PATCH] datapath-windows: OVS_PACKET_ATTR_PROBE
> > 
> > On Wed, Jul 01, 2015 at 06:57:50PM +0000, Alin Serdean wrote:
> > > Since commit:
> > > https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_open
> > > vs 
> > > witch_ovs_commit_2e460098bff351b9fddcb917447caa3b97a35d86&d=BQIGaQ&c
> > > =S 
> > > qcl0Ez6M0X8aeM67LKIiDJAXVeAw-YihVMNtXt-uEs&r=CWsgHUxi6ExLXY798tmo3LJ
> > > 4e 
> > > 3geGYp56lkcH-5cLCY&m=wSN1s5IDTOoE-dDGQWtmN87LEkQnYq71hKWcn7d3SJk&s=8
> > > _A Va78P_KXRWsNoVVtFSjNbBrJjyie8OjjjH4U953U&e=
> > > a new packet attribute was introduced.
> > > 
> > > This patch adds OVS_PACKET_ATTR_PROBE to nlPktExecPolicy in 
> > > datapath-windows and ignores it for the moment to maintain binary 
> > > compatibility.
> > > 
> > > Signed-off-by: Alin Gabriel Serdean 
> > > <[email protected]>
> > > Acked-by: Eitan Eliahu <[email protected]>
> > > ---
> > > This patch should be applied on master and branch-2.4
> > > v2: add acked-by
> > 
> > This patch makes me worry a bit.  The Linux kernel and OVS userspace 
> > implementations of Netlink ignore attributes that they do not recognize, 
> > which allows for some kinds of compatibility.  To me, this patch implies 
> > that the Windows datapath reports an error when it sees an unrecognized 
> > attribute.  Is that correct?  If so, then that should be changed, because 
> > otherwise it will cause compatibility problems in the future.
> > _______________________________________________
> > dev mailing list
> > [email protected]
> > https://urldefense.proofpoint.com/v2/url?u=http-3A__openvswitch.org_ma
> > ilman_listinfo_dev&d=BQIGaQ&c=Sqcl0Ez6M0X8aeM67LKIiDJAXVeAw-YihVMNtXt-
> > uEs&r=CWsgHUxi6ExLXY798tmo3LJ4e3geGYp56lkcH-5cLCY&m=wSN1s5IDTOoE-dDGQW
> > tmN87LEkQnYq71hKWcn7d3SJk&s=TZgQzcgvt8NDu-lf_W0nI9BkcWxoExr-9T2PSSonAb
> > k&e=
_______________________________________________
dev mailing list
[email protected]
http://openvswitch.org/mailman/listinfo/dev

Reply via email to