Re: [dpdk-dev] [PATCH] app/testpmd: fix MPLSoUDP encapsulation

[Adrien Mazarguil <adrien.mazarguil@6wind.com>]

On Thu, Nov 22, 2018 at 09:56:09AM +0000, Dekel Peled wrote:
> Thanks, PSB.
> 
> > -----Original Message-----
> > From: Adrien Mazarguil <adrien.mazarguil@6wind.com>
> > Sent: Thursday, November 22, 2018 11:05 AM
> > To: Dekel Peled <dekelp@mellanox.com>
> > Cc: wenzhuo.lu@intel.com; jingjing.wu@intel.com;
> > bernard.iremonger@intel.com; dev@dpdk.org; Ori Kam
> > <orika@mellanox.com>; Shahaf Shuler <shahafs@mellanox.com>
> > Subject: Re: [dpdk-dev] [PATCH] app/testpmd: fix MPLSoUDP encapsulation
> > 
> > On Mon, Nov 19, 2018 at 06:54:50PM +0200, Dekel Peled wrote:
> > > Set MPLS label value in appropriate location at mplsoudp_encap_conf,
> > > so it is correctly copied to rte_flow_item_mpls.
> > >
> > > Fixes: a1191d39cb57 ("app/testpmd: add MPLSoUDP encapsulation")
> > > Cc: orika@mellanox.com
> > >
> > > Signed-off-by: Dekel Peled <dekelp@mellanox.com>
> > > ---
> > >  app/test-pmd/cmdline.c | 4 ++--
> > >  1 file changed, 2 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/app/test-pmd/cmdline.c b/app/test-pmd/cmdline.c index
> > > 1275074..40e64cc 100644
> > > --- a/app/test-pmd/cmdline.c
> > > +++ b/app/test-pmd/cmdline.c
> > > @@ -15804,10 +15804,10 @@ static void
> > cmd_set_mplsoudp_encap_parsed(void *parsed_result,
> > >  	struct cmd_set_mplsoudp_encap_result *res = parsed_result;
> > >  	union {
> > >  		uint32_t mplsoudp_label;
> > > -		uint8_t label[3];
> > > +		uint8_t label[4];
> > >  	} id = {
> > >  		.mplsoudp_label =
> > > -			rte_cpu_to_be_32(res->label) &
> > RTE_BE32(0x00ffffff),
> > > +			rte_cpu_to_be_32(res->label<<4) &
> > RTE_BE32(0x00ffffff),
> > 
> > Just to be sure, since label is a 20-bit value, isn't the shift supposed to be 12
> > bits? In which case that mask is harmless but misleading. How about:
> > 
> >  .mplsoudp_label = rte_cpu_to_be32((res->label & 0xfffff) << 12);
> > 
> 
> Label is 20-bits value in a 24-bits field, see struct rte_flow_item_mpls.

OK, I know, what I missed was the following line:

 rte_memcpy(mplsoudp_encap_conf.label, &id.label[1], 3);

Just a suggestion then: using the same memcpy() offsets in both places for
clarity:

  rte_be32_t label = rte_cpu_to_be32(res->label << 12);

  memcpy(mplsodudp_encap_conf.label, &label, 3);

-- 
Adrien Mazarguil
6WIND