Re: [Idr] BGP Flowspec rules precedence order (RFC 5575)

Hi Christoph,
  Even in the  RFC5575bis,  the following is given  for comparing
non-prefix type components.

 else:
               # assuming comp_a.value, comp_b.value of type bytearray
               if len(comp_a.value) == len(comp_b.value):
                   if comp_a.value > comp_b.value:
                       return B_HAS_PRECEDENCE
                   if comp_a.value < comp_b.value:
                       return A_HAS_PRECEDENCE
                   # components equal -> continue with next component
               else:
                   common = min(len(comp_a.value), len(comp_b.value))
                   if comp_a.value[:common] > comp_b.value[:common]:
                       return B_HAS_PRECEDENCE
                   elif comp_a.value[:common] < comp_b.value[:common]:
                       return A_HAS_PRECEDENCE
                   # the first common bytes match
                   elif len(comp_a.value) > len(comp_b.value):
                       return A_HAS_PRECEDENCE
                   else:
                       return B_HAS_PRECEDENCE

*What is  comp_a.value here ? Is it the binary sting of [op,
value]/[op,bitmask] or only value/bitmask ?*

Thanks,

Pavana.

On Thu, Feb 15, 2018 at 3:11 AM, Christoph Loibl <c@tix.at> wrote:

> Hi Pavana,
>
> Did you have a look into the actual code (thanks to Job’s comment) that is
> contained in the RFC5575bis draft which should be identical from the
> behaviour:
>
> https://tools.ietf.org/html/draft-ietf-idr-rfc5575bis-06
>
> Christoph
>
> --
> Christoph Loibl
> c@tix.at | CL8-RIPE | PGP-Key-ID: 0x4B2C0055 | http://www.nextlayer.at
>
>
>
> On 12.02.2018, at 12:03, PVLR Pavana Murthy <pvlrpm@gmail.com> wrote:
>
> Hello,
>   In the RFC 5575, the following is given for the comparing the Flowspec
> components of types other then prefix.
>
> } else {
> common =
> MIN(component_length(comp1), component_length(comp2));
> cmp = memcmp(data(comp1), data(comp2), common);
> // not equal, lowest value has precedence
> // equal, longest string has precedence
> }
>
>
> Here, what does *data* refrer to  ?
>
> Is it the binary form of 1) [op, value]> / [op, bitmask]  or 2) Just
> [value] / [bitmask]
>
> eg:
>
>
> 1)  01 *18 58 58 58* 04 *01 46 81 50  ----> Dst.Prefix: 88.88.88.0/24
> <http://88.88.88.0/24>  Port: 70 | 80*
>
> 2)  01* 18 58 58 58 *04* 03 5a c5 6e    ---->   Dst.Prefix: 88.88.88.0/24
> <http://88.88.88.0/24>  Port: >=90 & <= 110*
>
> *In the above FS rules,  Dst. Prefix is same in both, so we need to
> compare the data of next type 4 (Port). *
> *So do we need to do memcmp of  (01 46 81 50) and  (03 5a c5 6e) ?*
>
> Thanks,
> Pavana*.*
>
>
>
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