[ovs-dev] [PATCH] ovn: Fix encoding of large logical output ports for STT.

Ben Pfaff blp at ovn.org
Tue May 30 14:59:20 UTC 2017


Thanks for the review!  I applied this to master, branch-2.7, and
branch-2.6.

On Mon, May 29, 2017 at 12:47:07PM +0200, Miguel Angel Ajo Pelayo wrote:
> Acked-By: Miguel Angel Ajo <majopela at redhat.com>
> 
> $ cat test.c
> #include <stdio.h>
> #include <stdint.h>
> 
> void main(void) {
> 
>     printf("uint16_t<<24=%Lx\n", ((uint16_t)0xf123)<<24);
>     printf("uint64_t<<24=%Lx\n", ((uint64_t)0xf123)<<24);
> }
> 
> linux: vagrant at gw1 in ~/ovs on
> $ ./test
> uint16_t<<24=23000000
> uint64_t<<24=f123000000
> 
> I tested it, and it seems (that at least for my gcc version 4.8.5 20150623
> (Red Hat 4.8.5-11) (GCC) on x64),
> 
> a 16 bit shifted, will result in 32bit output.
> a 64bit shifted will result in 64bit output.
> 
> 
> That could explain why this could have been working and not seen with <256
> ports.
> 
> 
> On Sat, May 27, 2017 at 6:24 AM, Ben Pfaff <blp at ovn.org> wrote:
> 
> > put_encapsulation() is meant to load the logical output port into bits
> > 24 to 40 of the tunnel ID metadata field, but 'outport << 24' did not
> > have that effect because outport has type uint16_t.  This fixes the
> > problem.
> >
> > Found by Coverity.
> >
> > Reported-at: https://scan3.coverity.com/reports.htm#v16889/p10449/
> > fileInstanceId=14763078&defectInstanceId=4304791&mergedDefectId=180391
> > Signed-off-by: Ben Pfaff <blp at ovn.org>
> > ---
> >  ovn/controller/physical.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/ovn/controller/physical.c b/ovn/controller/physical.c
> > index 457fc45414bd..532c7252e1ea 100644
> > --- a/ovn/controller/physical.c
> > +++ b/ovn/controller/physical.c
> > @@ -128,8 +128,8 @@ put_encapsulation(enum mf_field_id mff_ovn_geneve,
> >          put_load(outport, mff_ovn_geneve, 0, 32, ofpacts);
> >          put_move(MFF_LOG_INPORT, 0, mff_ovn_geneve, 16, 15, ofpacts);
> >      } else if (tun->type == STT) {
> > -        put_load(datapath->tunnel_key | (outport << 24), MFF_TUN_ID, 0,
> > 64,
> > -                 ofpacts);
> > +        put_load(datapath->tunnel_key | ((uint64_t) outport << 24),
> > +                 MFF_TUN_ID, 0, 64, ofpacts);
> >          put_move(MFF_LOG_INPORT, 0, MFF_TUN_ID, 40, 15, ofpacts);
> >      } else if (tun->type == VXLAN) {
> >          put_load(datapath->tunnel_key, MFF_TUN_ID, 0, 24, ofpacts);
> > --
> > 2.10.2
> >
> > _______________________________________________
> > dev mailing list
> > dev at openvswitch.org
> > https://mail.openvswitch.org/mailman/listinfo/ovs-dev
> >


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