Re: [dpdk-dev] [PATCH v2] net: introduce IPv4 ihl and version fields

[Olivier Matz <olivier.matz@6wind.com>]

On Fri, Sep 03, 2021 at 10:30:03AM +0300, getelson wrote:
> From: Gregory Etelson <getelson@nvidia.com>
> 
> RTE IPv4 header definition combines the `version' and `ihl'  fields
> into a single structure member.
> This patch introduces dedicated structure members for both `version'
> and `ihl' IPv4 fields. Separated header fields definitions allow to
> create simplified code to match on the IHL value in a flow rule.
> The original `version_ihl' structure member is kept for backward
> compatibility.
> 
> Signed-off-by: Gregory Etelson <getelson@nvidia.com>
> 
> Depends-on: f7383e7c7ec1 ("net: announce changes in IPv4 header access")

Acked-by: Olivier Matz <olivier.matz@6wind.com>

> --- a/lib/net/rte_ip.h
> +++ b/lib/net/rte_ip.h
> @@ -38,7 +38,21 @@ extern "C" {
>   * IPv4 Header
>   */
>  struct rte_ipv4_hdr {
> -	uint8_t  version_ihl;		/**< version and header length */
> +	__extension__
> +	union {
> +		uint8_t version_ihl;    /**< version and header length */
> +		struct {
> +#if RTE_BYTE_ORDER == RTE_LITTLE_ENDIAN
> +			uint8_t ihl:4;
> +			uint8_t version:4;
> +#elif RTE_BYTE_ORDER == RTE_BIG_ENDIAN
> +			uint8_t version:4;
> +			uint8_t ihl:4;

nit: although it's obvious, we may want to add /**< IP version */ and
/**< header length */ for these new fields, for consistency with the
rest of the structure.