Re: [PATCH v2 1/2] mbuf: introduce new Tx offload flag for MPLS-in-UDP

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

Hi Rasesh,

On Wed, 7 Jun 2017 00:43:48 -0700, Rasesh Mody <rasesh.mody@cavium.com> wrote:
> From: Harish Patil <harish.patil@cavium.com>
> 
> Some PMDs need to know the tunnel type in order to handle advance TX
> features. This patch adds a new TX offload flag for MPLS-in-UDP packets.
> 
> Signed-off-by: Harish Patil <harish.patil@cavium.com>
> ---
>  lib/librte_mbuf/rte_mbuf.c |    2 ++
>  lib/librte_mbuf/rte_mbuf.h |   17 ++++++++++-------
>  2 files changed, 12 insertions(+), 7 deletions(-)
> 
> diff --git a/lib/librte_mbuf/rte_mbuf.c b/lib/librte_mbuf/rte_mbuf.c
> index 0e3e36a..c2793fb 100644
> --- a/lib/librte_mbuf/rte_mbuf.c
> +++ b/lib/librte_mbuf/rte_mbuf.c
> @@ -410,6 +410,7 @@ const char *rte_get_tx_ol_flag_name(uint64_t mask)
>  	case PKT_TX_TUNNEL_IPIP: return "PKT_TX_TUNNEL_IPIP";
>  	case PKT_TX_TUNNEL_GENEVE: return "PKT_TX_TUNNEL_GENEVE";
>  	case PKT_TX_MACSEC: return "PKT_TX_MACSEC";
> +	case PKT_TX_TUNNEL_MPLSINUDP: return "PKT_TX_TUNNEL_MPLSINUDP";
>  	default: return NULL;
>  	}
>  }
> @@ -441,6 +442,7 @@ const char *rte_get_tx_ol_flag_name(uint64_t mask)
>  		{ PKT_TX_TUNNEL_GENEVE, PKT_TX_TUNNEL_MASK,
>  		  "PKT_TX_TUNNEL_NONE" },
>  		{ PKT_TX_MACSEC, PKT_TX_MACSEC, NULL },
> +		{ PKT_TX_TUNNEL_MPLSINUDP, PKT_TX_TUNNEL_MPLSINUDP, NULL },
>  	};
>  	const char *name;
>  	unsigned int i;
> diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
> index 1cb0310..27ad421 100644
> --- a/lib/librte_mbuf/rte_mbuf.h
> +++ b/lib/librte_mbuf/rte_mbuf.h
> @@ -197,19 +197,22 @@
>   * Offload the MACsec. This flag must be set by the application to enable
>   * this offload feature for a packet to be transmitted.
>   */
> -#define PKT_TX_MACSEC        (1ULL << 44)
> +#define PKT_TX_MACSEC        (1ULL << 43)

I'm not sure it is suitable to change the value of an existing
flag, since it breaks the ABI.


>  /**
> - * Bits 45:48 used for the tunnel type.
> + * Bits 44:48 used for the tunnel type.
>   * When doing Tx offload like TSO or checksum, the HW needs to configure the
>   * tunnel type into the HW descriptors.
>   */
> -#define PKT_TX_TUNNEL_VXLAN   (0x1ULL << 45)
> -#define PKT_TX_TUNNEL_GRE     (0x2ULL << 45)
> -#define PKT_TX_TUNNEL_IPIP    (0x3ULL << 45)
> -#define PKT_TX_TUNNEL_GENEVE  (0x4ULL << 45)
> +/**< TX packet with MPLS-in-UDP RFC 7510 header. */
> +#define PKT_TX_TUNNEL_MPLSINUDP (0x1ULL << 44)
> +
> +#define PKT_TX_TUNNEL_VXLAN   (0x2ULL << 44)
> +#define PKT_TX_TUNNEL_GRE     (0x3ULL << 44)
> +#define PKT_TX_TUNNEL_IPIP    (0x4ULL << 44)
> +#define PKT_TX_TUNNEL_GENEVE  (0x5ULL << 45)
>  /* add new TX TUNNEL type here */
> -#define PKT_TX_TUNNEL_MASK    (0xFULL << 45)
> +#define PKT_TX_TUNNEL_MASK    (0x1FULL << 44)
>  
>  /**
>   * Second VLAN insertion (QinQ) flag.

I dont understand why adding
#define PKT_TX_TUNNEL_MPLSINUDP (0x5ULL << 45)
wouldn't do the job?

Currently, the tunnel mask is 0xF << 45, which gives 16 possible values.


Regards,
Olivier