[dpdk-dev] [PATCH] librte_lpm: define tbl entry reversely for big endian
Xuelin Shi
xuelin.shi at freescale.com
Thu Mar 5 03:12:12 CET 2015
Hi Bruce,
Yes, it needs to swap the fields. The bit field is first identified as the uint8_t and then packed.
Thanks,
Shi xuelin
> -----Original Message-----
> From: Bruce Richardson [mailto:bruce.richardson at intel.com]
> Sent: Wednesday, March 04, 2015 18:48
> To: Shi Xuelin-B29237
> Cc: thomas.monjalon at 6wind.com; dev at dpdk.org
> Subject: Re: [PATCH] librte_lpm: define tbl entry reversely for big
> endian
>
> On Wed, Mar 04, 2015 at 02:34:12PM +0800, xuelin.shi at freescale.com wrote:
> > From: Xuelin Shi <xuelin.shi at freescale.com>
> >
> > This module uses type conversion between struct and int.
> > Also truncation and comparison is used with this int.
> > It is not safe for different endian arch.
> >
> > Add ifdef for big endian struct to fix this issue.
> >
> > Signed-off-by: Xuelin Shi <xuelin.shi at freescale.com>
> > ---
> > lib/librte_lpm/rte_lpm.h | 19 +++++++++++++++++++
> > 1 file changed, 19 insertions(+)
> >
> > diff --git a/lib/librte_lpm/rte_lpm.h b/lib/librte_lpm/rte_lpm.h index
> > 1af150c..08a2859 100644
> > --- a/lib/librte_lpm/rte_lpm.h
> > +++ b/lib/librte_lpm/rte_lpm.h
> > @@ -96,6 +96,7 @@ extern "C" {
> > /** Bitmask used to indicate successful lookup */
> > #define RTE_LPM_LOOKUP_SUCCESS 0x0100
> >
> > +#if RTE_BYTE_ORDER == RTE_LITTLE_ENDIAN
> > /** @internal Tbl24 entry structure. */ struct rte_lpm_tbl24_entry {
> > /* Stores Next hop or group index (i.e. gindex)into tbl8. */ @@
> > -117,6 +118,24 @@ struct rte_lpm_tbl8_entry {
> > uint8_t valid_group :1; /**< Group validation flag. */
> > uint8_t depth :6; /**< Rule depth. */
> > };
> > +#else
> > +struct rte_lpm_tbl24_entry {
> > + uint8_t depth :6;
> > + uint8_t ext_entry :1;
> > + uint8_t valid :1;
>
> Since endianness only refers to the order of bytes within a word, do the
> bitfields within the uint8_t really need to be swapped around too?
>
> /Bruce
>
> > + union {
> > + uint8_t tbl8_gindex;
> > + uint8_t next_hop;
> > + };
> > +};
> > +
> > +struct rte_lpm_tbl8_entry {
> > + uint8_t depth :6;
> > + uint8_t valid_group :1;
> > + uint8_t valid :1;
> > + uint8_t next_hop;
> > +};
> > +#endif
> >
> > /** @internal Rule structure. */
> > struct rte_lpm_rule {
> > --
> > 1.9.1
> >
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