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 > >
