[PATCH v3 2/3] ethdev: add compare item

[Suanming Mou]

> -----Original Message-----
> From: Ferruh Yigit <ferruh.yigit at amd.com>
> Sent: Thursday, February 1, 2024 12:46 AM
> To: Ori Kam <orika at nvidia.com>; Suanming Mou <suanmingm at nvidia.com>;
> Aman Singh <aman.deep.singh at intel.com>; Yuying Zhang
> <yuying.zhang at intel.com>; NBU-Contact-Thomas Monjalon (EXTERNAL)
> <thomas at monjalon.net>; Andrew Rybchenko
> <andrew.rybchenko at oktetlabs.ru>
> Cc: dev at dpdk.org
> Subject: Re: [PATCH v3 2/3] ethdev: add compare item
> 
> On 1/31/2024 3:56 PM, Ori Kam wrote:
> > Hi
> >
> >> -----Original Message-----
> >> From: Suanming Mou <suanmingm at nvidia.com>
> >> Sent: Wednesday, January 31, 2024 4:48 AM
> >>
> >> Hi,
> >>
> >>> -----Original Message-----
> >>> From: Ferruh Yigit <ferruh.yigit at amd.com>
> >>> Sent: Wednesday, January 31, 2024 1:34 AM
> >>> To: Suanming Mou <suanmingm at nvidia.com>; Ori Kam
> >> <orika at nvidia.com>;
> >>> Aman Singh <aman.deep.singh at intel.com>; Yuying Zhang
> >>> <yuying.zhang at intel.com>; NBU-Contact-Thomas Monjalon (EXTERNAL)
> >>> <thomas at monjalon.net>; Andrew Rybchenko
> >>> <andrew.rybchenko at oktetlabs.ru>
> >>> Cc: dev at dpdk.org
> >>> Subject: Re: [PATCH v3 2/3] ethdev: add compare item
> >>>
> >>> On 1/15/2024 9:13 AM, Suanming Mou wrote:
> >>>> The new item type is added for the case user wants to match traffic
> >>>> based on packet field compare result with other fields or immediate
> >>>> value.
> >>>>
> >>>> e.g. take advantage the compare item user will be able to
> >>>> accumulate a IPv4/TCP packet's TCP data_offset and IPv4 IHL field
> >>>> to a tag register, then compare the tag register with IPv4 header
> >>>> total length to understand the packet has payload or not.
> >>>>
> >>>
> >>> ack, above sample makes it easier to understand.
> >>>
> >>> This patch is adding testpmd commands, can you please provide some
> >> sample
> >>> commands in commit log?
> >>> The more samples are better, as far as I remember there was a
> >>> testpmd documentation that documents the sample usages, can you
> >>> please check
> >> for it?
> >
> > [Snip ..]
> >
> >>>
> >>>> +/**
> >>>> + * @warning
> >>>> + * @b EXPERIMENTAL: this structure may change without prior notice
> >>>> + *
> >>>> + * Field description for packet field.
> >>>> + */
> >>>> +struct rte_flow_field_data {
> >>>> +	enum rte_flow_field_id field; /**< Field or memory type ID. */
> >>>> +	union {
> >>>> +		struct {
> >>>> +			/** Encapsulation level and tag index or flex item
> >>> handle. */
> >>>> +			union {
> >>>> +				struct {
> >>>> +					/**
> >>>> +					 * Packet encapsulation level
> >> containing
> >>>> +					 * the field to modify.
> >>>> +					 *
> >>>> +					 * - @p 0 requests the default
> >> behavior.
> >>>> +					 *   Depending on the packet type, it
> >>>> +					 *   can mean outermost, innermost
> >> or
> >>>> +					 *   anything in between.
> >>>> +					 *
> >>>> +					 *   It basically stands for the
> >>>> +					 *   innermost encapsulation level.
> >>>> +					 *   Modification can be performed
> >>>> +					 *   according to PMD and device
> >>>> +					 *   capabilities.
> >>>> +					 *
> >>>> +					 * - @p 1 requests modification to be
> >>>> +					 *   performed on the outermost
> >> packet
> >>>> +					 *   encapsulation level.
> >>>> +					 *
> >>>> +					 * - @p 2 and subsequent values
> >>> request
> >>>> +					 *   modification to be performed on
> >>>> +					 *   the specified inner packet
> >>>> +					 *   encapsulation level, from
> >>>> +					 *   outermost to innermost (lower to
> >>>> +					 *   higher values).
> >>>> +					 *
> >>>> +					 * Values other than @p 0 are not
> >>>> +					 * necessarily supported.
> >>>> +					 *
> >>>> +					 * @note that for MPLS field,
> >>>> +					 * encapsulation level also include
> >>>> +					 * tunnel since MPLS may appear in
> >>>> +					 * outer, inner or tunnel.
> >>>> +					 */
> >>>> +					uint8_t level;
> >>>> +					union {
> >>>> +						/**
> >>>> +						 * Tag index array inside
> >>>> +						 * encapsulation level.
> >>>> +						 * Used for VLAN, MPLS or
> >> TAG
> >>> types.
> >>>> +						 */
> >>>> +						uint8_t tag_index;
> >>>> +						/**
> >>>> +						 * Geneve option identifier.
> >>>> +						 * Relevant only for
> >>>> +						 *
> >>> RTE_FLOW_FIELD_GENEVE_OPT_XXXX
> >>>> +						 * modification type.
> >>>> +						 */
> >>>> +						struct {
> >>>> +							/**
> >>>> +							 * Geneve option
> >> type.
> >>>> +							 */
> >>>> +							uint8_t type;
> >>>> +							/**
> >>>> +							 * Geneve option
> >> class.
> >>>> +							 */
> >>>> +							rte_be16_t class_id;
> >>>> +						};
> >>>> +					};
> >>>> +				};
> >>>> +				struct rte_flow_item_flex_handle
> >> *flex_handle;
> >>>> +			};
> >>>> +			/** Number of bits to skip from a field. */
> >>>> +			uint32_t offset;
> >>>> +		};
> >>>> +		/**
> >>>> +		 * Immediate value for RTE_FLOW_FIELD_VALUE, presented
> >> in
> >>> the
> >>>> +		 * same byte order and length as in relevant
> >> rte_flow_item_xxx.
> >>>> +		 * The immediate source bitfield offset is inherited from
> >>>> +		 * the destination's one.
> >>>> +		 */
> >>>> +		uint8_t value[16];
> >>>> +		/**
> >>>> +		 * Memory address for RTE_FLOW_FIELD_POINTER, memory
> >>> layout
> >>>> +		 * should be the same as for relevant field in the
> >>>> +		 * rte_flow_item_xxx structure.
> >>>> +		 */
> >>>> +		void *pvalue;
> >>>> +	};
> >>>> +};
> >>>> +
> >>>>
> >>>
> >>> I am aware that you are just moving the above struct, but it is
> >>> nested too
> >> much
> >>> which is making it hard to read.
> >>>
> >>> As you are touching it, can we extract some structs and make this
> >>> struct less nested, what do you think?
> >>> Of course it needs to be done in separate patch, as a
> >>> preperation/clean-up
> >> patch
> >>> before moving it around.
> >>
> >> Agree the struct maybe a bit nested. But not sure how it was
> >> discussed before during the last new member was added... @Ori, Do you
> >> have any idea about this?
> >>
> >
> > As far as I remember, it was never discussed,
> >
> > I think for this series we should keep it as is, and revise it later.
> >
> 
> If you don't want to make this set more complex with this, that is OK as long
> as it is addressed at some point.

OK, thanks. As it is addressed, will update v4 soon.

> 
> > Best,
> > Ori
> >> And if it is really expected, I believe another new thread is worth
> >> for that change,  better not be in that series.
> >> Need to discuss the new struct name and other stuff. What do you think?
> >>
> >>>
> >>> <...>
> >>>
> >>>> +/**
> >>>> + *
> >>>> + * RTE_FLOW_ITEM_TYPE_COMPARE
> >>>> + *
> >>>> + * Matches the packet with compare result.
> >>>> + *
> >>>> + * The operation means a compare with b result.
> >>>> + */
> >>>> +struct rte_flow_item_compare {
> >>>> +	enum rte_flow_item_compare_op operation; /* The compare
> >> operation.
> >>> */
> >>>> +	struct rte_flow_field_data a;		 /* Field be compared.  */
> >>>> +	struct rte_flow_field_data b;		 /* Field as comparator. */
> >>>>
> >>>
> >>> Variable names 'a' and 'b' are not descriptive although it may be OK
> >>> since
> >> there is
> >>> no significance to the values, but other option can be 'first' and
> >>> 'second',
> >> but
> >>> overall not strong opinion.
> >>
> >> Yes, thanks for the suggestion, in fact we also discussed about the
> >> name a lot, finally we choose the widely used 'a' and 'b'
> >>
> >> Thanks
> >