[dpdk-dev] [PATCH v4 16/21] ethdev: define structures for configuring flexible payload

[Wu, Jingjing]

> -----Original Message-----
> From: Thomas Monjalon [mailto:thomas.monjalon at 6wind.com]
> Sent: Tuesday, October 28, 2014 10:15 PM
> To: Wu, Jingjing
> Cc: dev at dpdk.org
> Subject: Re: [dpdk-dev] [PATCH v4 16/21] ethdev: define structures for
> configuring flexible payload
> 
> 2014-10-22 09:01, Jingjing Wu:
> > +/**
> > + * A structure defined a field vector to specify each field.
> > + */
> > +struct rte_eth_field_vector {
> > +	uint8_t offset;   /**< Source word offset */
> > +	uint8_t size;     /**< Field Size defined in word units */
> > +};
> 
> I'm sorry but I don't understand this patch at all.
> I think the reason is that I need more information about flex filter.
> 

Yes, it is a little difficult to understand the behavior. Let me explain it as I can.
<1> flex words:
We can select where the 8 flex words are. It can be constituted of 1-3 partitions.
Each partition is defined as rte_eth_field_vector. 
For example:
if we set 
rte_eth_flex_payload_cfg = {
	.type = RTE_ETH_L4_PAYLOAD;
	.nb_field = 1;
	.field = {
		{0, 8},  /*offset = 0, size =8*/
	};
};
This means the 8 words from the beginning of l4 payload will be consider as flex words.
If we set 
rte_eth_flex_payload_cfg = {
	.type = RTE_ETH_L4_PAYLOAD;
	.nb_field = 1;
	.field = {
		{0, 2},  /*offset = 0, size =2*/
		{4, 6},  /*offset = 4, size =6*/
	};
};
This means the 2 words from the beginning of l4 payload plus 6 words form the offset 4
will be consider as flex words.

<2> flex mask:
As the <1> configuration, we already select 8 words as flex words. Then the flex mask
Will help us to define whether these word will participate in comparing. 
The flex mask can be constituted of 2 partitions. One is word mask, another is bit mask.
Word mask is defined in rte_eth_fdir_flex_masks.words_mask, it means bit i enables word i of flex words.
rte_eth_fdir_flex_masks.field specify each word's bit mask, Fortville support 2 word bitmask.

> > +
> > +/**
> > + * payload type
> > + */
> > +enum rte_eth_payload_type {
> > +	RTE_ETH_PAYLOAD_UNKNOWN = 0,
> > +	RTE_ETH_L2_PAYLOAD,
> > +	RTE_ETH_L3_PAYLOAD,
> > +	RTE_ETH_L4_PAYLOAD,
> > +};
> > +
> >  /**
> >   * flow type
> >   */
> > @@ -92,6 +111,30 @@ enum rte_eth_flow_type {  };
> >
> >  /**
> > + * A structure used to select fields extracted from the protocol
> > +layers to
> > + * the Field Vector as flexible payload for filter  */ struct
> > +rte_eth_flex_payload_cfg {
> > +	enum rte_eth_payload_type type;  /**< payload type */
> > +	uint8_t nb_field;                /**< the number of following fields */
> > +	struct rte_eth_field_vector field[0]; };
> > +
> > +#define RTE_ETH_FDIR_CFG_FLX      0x0001
> > +/**
> > + * A structure used to config FDIR filter global set
> > + * to support RTE_ETH_FILTER_FDIR with RTE_ETH_FILTER_SET operation.
> > + */
> > +struct rte_eth_fdir_cfg {
> > +	uint16_t cmd;  /**< sub command  */
> > +	/**
> > +	 * A pointer to structure for the configuration e.g.
> > +	 * struct rte_eth_flex_payload_cfg for FDIR_CFG_FLX
> > +	*/
> > +	void *cfg;
> > +};