[RFC] ethdev: add template table insertion and matching types

[Ori Kam]

Hi Alexander,

> -----Original Message-----
> From: Alexander Kozyrev <akozyrev at nvidia.com>
> Sent: Wednesday, 14 December 2022 4:21
> 
> Bring more flexibility and control over both flow rule insertion
> and packet matching mechanisms. Introduce 2 new flow table types:
> 
> 1. Allow a user to specify the insertion type used in template tables.
> The insertion type is responsible for choosing the appropriate key
> value used to map inserted flow rules into a template table.
> 
> Flow rules can be inserted by calculating the hash value for
> the pattern or inserted by index via the new create_by_index() API.
> The idea of the index-based insertion is to avoid additional matches
> and simply execute predefined actions after jumping to the index.
> 
> The insertion to an already existing index is undefined and
> depends on PMD implementation. An old rule must be destroyed first.
> The index cannot be bigger than the size of the table.
> 
> 2. Allow a user to specify the hash calculation function used in template
> tables. The hash calculation type is responsible for the calculation of
> the flow rule index a packet would hit upon arrival at the table.
> 
> Control over this is useful for applications with custom RSS algorithms,
> for example. An application can select various packet fields to serve as
> a hash calculation source and jump to the appropriate flow rule location.
> The RSS hash result will be used as the index in the table. For the linear
> hash function, the mapping is one-to-one and the hash result is the index.
> For other hash functions, the index is the hash result module table size.
> The RSS hash result can be retrieved via modify_field API: HASH_RESULT.
> 
> Signed-off-by: Alexander Kozyrev <akozyrev at nvidia.com>
> ---

Acked-by: Ori Kam <orika at nvidia.com>
Best,
Ori