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

[Zhao1, Wei]

Hi, Adrien

> -----Original Message-----
> From: Adrien Mazarguil [mailto:adrien.mazarguil at 6wind.com]
> Sent: Wednesday, May 24, 2017 3:32 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
> 
> On Wed, May 24, 2017 at 03:32:02AM +0000, Zhao1, Wei wrote:
> > 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> }.
> 
> Right, I misread your original pattern[] intent. You would get such a pattern
> by specifying \x01\x23 (just like C string literals). It would even accept octal
> notation "\01\043". Both would yield { 0x01, 0x23 }.
> 
> Does something like that satisfy the requirements?

Yes, After the repeat, I think we both understand each other.

> 
> > And this problem is not a block for code develop for 17.08, but it is needed
> for tester and user in the feature.
> 
> Well, I've actually started implementing the above long ago in testpmd but
> didn't have time to clean up the patch and submit it yet (moreover it was not
> needed until now). If the idea works for your use case, I can attempt to do
> that soon.
> 

All that decision is up to you, and I think it is great.

> > > > 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
> 
> --
> Adrien Mazarguil
> 6WIND