[dpdk-dev] [PATCH v3 01/25] ethdev: introduce generic flow API

[Zhao1, Wei]

Hi,

> -----Original Message-----
> From: Adrien Mazarguil [mailto:adrien.mazarguil at 6wind.com]
> Sent: Tuesday, May 23, 2017 5:51 PM
> To: Zhao1, Wei <wei.zhao1 at intel.com>
> Cc: dev at dpdk.org; Xing, Beilei <beilei.xing at intel.com>
> Subject: Re: [dpdk-dev] [PATCH v3 01/25] ethdev: introduce generic flow API
>
> Hi Wei,
>
> On Tue, May 23, 2017 at 06:07:20AM +0000, Zhao1, Wei wrote:
> > Hi,  Adrien
> >
> > > +struct rte_flow_item_raw {
> > > + uint32_t relative:1; /**< Look for pattern after the previous item. */
> > > + uint32_t search:1; /**< Search pattern from offset (see also limit). */
> > > + uint32_t reserved:30; /**< Reserved, must be set to zero. */
> > > + int32_t offset; /**< Absolute or relative offset for pattern. */
> > > + uint16_t limit; /**< Search area limit for start of pattern. */
> > > + uint16_t length; /**< Pattern length. */
> > > + uint8_t pattern[]; /**< Byte string to look for. */ };
> >
> > When I use this API to test igb flex filter, I find that in the struct
> > rte_flow_item_raw, the member  pattern is not the same as my purpose.
> > For example, If I type in  " flow create 0 ingress pattern raw relative is 0
> pattern is 0123  / end actions queue index 1 / end "
> > What I get in NIC layer is  pattern[]={ 0x30, 0x31, 0x32, 0x33, 0x0 <repeats
> 124 times> }.
> > But what I need is pattern[]={0x01, 0x23, 0x0 <repeats 126 times>}
>
> Similar limitation as I answered in [1] then. This is not a problem in the
> rte_flow API, it's only that the testpmd parser currently provides
> unprocessed strings to the PMD, and there is currently no method to work
> around that.
>
> > About the format change of flex_filter, I have reference to the
> > testpmd function cmd_flex_filter_parsed(), There is details of format
> change from ASIC code to data, for example:
> >
> >             for (i = 0; i < len; i++) {
> >                         c = bytes_ptr[i];
> >                         if (isxdigit(c) == 0) {
> >                                     /* invalid characters. */
> >                                     printf("invalid input\n");
> >                                     return;
> >                         }
> >                         val = xdigit2val(c);
> >                         if (i % 2) {
> >                                     byte |= val;
> >                                     filter.bytes[j] = byte;
> >                                     printf("bytes[%d]:%02x ", j, filter.bytes[j]);
> >                                     j++;
> >                                     byte = 0;
> >                         } else
> >                                     byte |= val << 4;
> >             }
> >
> > and there is also usage example in the DPDK document testpmd_app_ug-
> 16.11.pdf:
> > (it also not use ASIC code)
> >
> > testpmd> flex_filter 0 add len 16 bytes
> > testpmd> 0x00000000000000000000000008060000 \
> > mask 000C priority 3 queue 3
>
> I understand, the difference between both commands is only that unlike
> flex_filter, flow does not interpret the provided string as hexadecimal.
>
> > so, will our new generic flow API align to the old format in flex byte filter in
> 17.08 or in the future?
>
> What I have in mind instead is a printf-like input method. Using the rule you
> provided above:
>
>  flow create 0 ingress pattern raw relative is 0 pattern is 0123  / end actions
> queue index 1 / end
>
> Will always yield "0123", however:
>
>  flow create 0 ingress pattern raw relative is 0 pattern is \x00\x01\x02\x03  /
> end actions queue index 1 / end
>
> Will yield the intended pattern. Currently this format is interpreted as is
> (you'll get "\x00\x01\x02\x03") however escape interpretation is in the plans.
>

Thank you for your explanation. But there is some key point I want to repeat:
For example, If I type in  " flow create 0 ingress pattern raw relative is 0 pattern is 0123  / end actions queue index 1 / end "
Or maybe more accurate, " flow create 0 ingress pattern raw relative is 0 pattern is 0x0123  / end actions queue index 1 / end "
what I need is pattern[]={0x01, 0x23, 0x0 <repeats 126 times>}.
not  pattern[]={ 0x00, 0x01, 0x02, 0x03, 0x0 <repeats 124 times> }.
And also, not  pattern[]={ 0x30, 0x31, 0x32, 0x33, 0x0 <repeats 124 times> }.
And this problem is not a block for code develop for 17.08, but it is needed for tester and user in the feature.

> > At least in the struct rte_flow_item_raw, the member  pattern is the same
> as old filter?
>
> It is the same as the old filter, except you cannot provide it in hexadecimal
> format yet. No changes needed on the PMD side in any case.
>
> Again, this is only a testpmd implementation issue, that doesn't prevent
> developers from creating programs that directly provide binary data to RAW
> items, there's no such limitation.
>
> [1] http://dpdk.org/ml/archives/dev/2017-May/065798.html
>
> --
> Adrien Mazarguil
> 6WIND