Re: [dpdk-dev] [PATCH v4] mbuf: fix of enabling all newly added RX error flags

["Zhang, Helin" <helin.zhang@intel.com>]

> -----Original Message-----
> From: Thomas Monjalon [mailto:thomas.monjalon@6wind.com]
> Sent: Wednesday, December 10, 2014 11:26 PM
> To: Zhang, Helin
> Cc: dev@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH v4] mbuf: fix of enabling all newly added RX
> error flags
> 
> 2014-12-10 13:50, Zhang, Helin:
> >
> > > -----Original Message-----
> > > From: Thomas Monjalon [mailto:thomas.monjalon@6wind.com]
> > > Sent: Wednesday, December 10, 2014 5:35 PM
> > > To: Zhang, Helin
> > > Cc: dev@dpdk.org
> > > Subject: Re: [dpdk-dev] [PATCH v4] mbuf: fix of enabling all newly
> > > added RX error flags
> > >
> > > 2014-12-10 16:55, Helin Zhang:
> > > > Before redefining mbuf structure, there was lack of free bits in 'ol_flags'
> > > > (32 bits in total) for new RX or TX flags. So it tried to reuse
> > > > existant bits as most as possible, or even assigning 0 to some of
> > > > bit flags. After new mbuf structure defined, there are quite a lot
> > > > of free bits. So those newly added bit flags should be assigned
> > > > with correct and valid bit values, and getting their names should
> > > > be enabled as well. Note that 'RECIP' should be removed, as nowhere
> uses it.
> > > > 'PKT_RX_ERR' is defined to replace all other error bit flags, e.g.
> > > > MAC error,
> > > Oversize error, header buffer overflow error.
> > > >
> > > > Signed-off-by: Helin Zhang <helin.zhang@intel.com>
> > > > ---
> > > >  lib/librte_mbuf/rte_mbuf.c      |  7 ++-----
> > > >  lib/librte_mbuf/rte_mbuf.h      |  9 +++------
> > > >  lib/librte_pmd_i40e/i40e_rxtx.c | 37
> > > > ++++++++++++++++++++-----------------
> > > >  3 files changed, 25 insertions(+), 28 deletions(-)
> > > >
> > > > v2 changes:
> > > > * Removed error flag of 'ECIPE' processing only in both i40e PMD and
> mbuf.
> > > All
> > > >   other error flags were added back.
> > > > * Assigned error flags with correct and valid values, as their previous
> values
> > > >   were invalid.
> > > > * Enabled getting all error flag names.
> > > >
> > > > v3 changes:
> > > > * 'PKT_RX_ERR' is defined to replace error bit flags of MAC error, Oversize
> > > >   error, header buffer overflow error.
> > > > * Removed assigning values to PKT_TX_* bit flags, as it has
> > > > already been
> > > done
> > > >   in another packet set.
> > > >
> > > > v4 changes:
> > > > * Renamed 'PKT_RX_EIP_CKSUM_BAD' to
> 'PKT_RX_OUTER_IP_CKSUM_BAD'.
> > > > * Fixed the bug of checking error bits of 'Descriptor oversize' and
> > > >   'Header buffer oversize'.
> > > > * Added debug logs for each RX error.
> > > [...]
> > > > --- a/lib/librte_mbuf/rte_mbuf.h
> > > > +++ b/lib/librte_mbuf/rte_mbuf.h
> > > > @@ -83,12 +83,7 @@ extern "C" {
> > > >  #define PKT_RX_RSS_HASH      (1ULL << 1)  /**< RX packet with
> RSS
> > > hash result. */
> > > >  #define PKT_RX_FDIR          (1ULL << 2)  /**< RX packet with
> FDIR
> > > match indicate. */
> > > >  #define PKT_RX_L4_CKSUM_BAD  (1ULL << 3)  /**< L4 cksum of RX
> pkt.
> > > is
> > > > not OK. */ -#define PKT_RX_IP_CKSUM_BAD  (1ULL << 4)  /**< IP
> > > > cksum of RX pkt. is not OK. */ -#define PKT_RX_EIP_CKSUM_BAD (0ULL
> > > > << 0)  /**<
> > > External IP header checksum error. */
> > > > -#define PKT_RX_OVERSIZE      (0ULL << 0)  /**< Num of desc of an
> RX
> > > pkt oversize. */
> > > > -#define PKT_RX_HBUF_OVERFLOW (0ULL << 0)  /**< Header buffer
> > > overflow. */
> > > > -#define PKT_RX_RECIP_ERR     (0ULL << 0)  /**< Hardware
> processing
> > > error. */
> > > > -#define PKT_RX_MAC_ERR       (0ULL << 0)  /**< MAC error. */
> > > > +#define PKT_RX_IP_CKSUM_BAD  (1ULL << 4)  /**< IP (or inner IP)
> > > > +header checksum error. */
> > >
> > > It can be also an outer IP header in case the device don't support
> > > tunneling or is not configured to detect it.
> >
> > For non-tunneling case, no outer/inner at all, it just has the IP
> > header. The bit flag indicates the IP header checksum error.
> > For tunneling case, this bit flag indicates the inner IP header
> > checksum error, another one for outer IP header checksum error.
> > So I don't think this bit can be treated as outer.
> 
> I think you didn't understand my comment.
> I talk about NICs which don't have tunneling support.
> In this case, the outer IP header is seen as a simple IP header.
> So, depending on which port is receiving a tunneled packet, this flag or the
> dedicated one can be used for outer IP checksum.
I think I did understand your point. For those port which does not support tunneling,
if a 'tunneling' packet received, it never knows that's tunneling packet, it always treats
it as a general IP packet. The "inner" IP is just part of its data. For this case, no outer
or inner at all, just an IP header.

> 
> I just suggest to remove the part "(or inner IP)" of the comment.
> Do you agree?
I got it, actually I wanted to describe it as (or inner IP for tunneling), as the macro name
does not tell it could be inner IP header checksum error for tunneling case.

Regards,
Helin
> 
> --
> Thomas