[dpdk-dev] [PATCH v2 02/20] mbuf: enhance the API documentation of offload flags

[Zhang, Helin]

> -----Original Message-----
> From: Olivier Matz [mailto:olivier.matz at 6wind.com]
> Sent: Wednesday, February 4, 2015 5:25 PM
> To: dev at dpdk.org
> Cc: Ananyev, Konstantin; Liu, Jijiang; Zhang, Helin; olivier.matz at 6wind.com
> Subject: [PATCH v2 02/20] mbuf: enhance the API documentation of offload
> flags
> 
> Based on http://dpdk.org/ml/archives/dev/2015-January/011127.html
> 
> Also adapt the csum forward engine code to the API.
> 
> Signed-off-by: Olivier Matz <olivier.matz at 6wind.com>
> ---
>  app/test-pmd/csumonly.c    |  6 +++---
>  lib/librte_mbuf/rte_mbuf.h | 43
> ++++++++++++++++++++++++++++++++++++-------
>  2 files changed, 39 insertions(+), 10 deletions(-)
> 
> diff --git a/app/test-pmd/csumonly.c b/app/test-pmd/csumonly.c index
> 41711fd..4b438d1 100644
> --- a/app/test-pmd/csumonly.c
> +++ b/app/test-pmd/csumonly.c
> @@ -183,16 +183,15 @@ process_inner_cksums(void *l3_hdr, uint16_t
> ethertype, uint16_t l3_len,
>  		ipv4_hdr = l3_hdr;
>  		ipv4_hdr->hdr_checksum = 0;
> 
> +		ol_flags |= PKT_TX_IPV4;
>  		if (tso_segsz != 0 && l4_proto == IPPROTO_TCP) {
>  			ol_flags |= PKT_TX_IP_CKSUM;
>  		} else {
>  			if (testpmd_ol_flags & TESTPMD_TX_OFFLOAD_IP_CKSUM)
>  				ol_flags |= PKT_TX_IP_CKSUM;
> -			else {
> +			else
>  				ipv4_hdr->hdr_checksum =
>  					rte_ipv4_cksum(ipv4_hdr);
> -				ol_flags |= PKT_TX_IPV4;
> -			}
>  		}
>  	} else if (ethertype == _htons(ETHER_TYPE_IPv6))
>  		ol_flags |= PKT_TX_IPV6;
> @@ -261,6 +260,7 @@ process_outer_cksums(void *outer_l3_hdr, uint16_t
> outer_ethertype,
> 
>  	if (outer_ethertype == _htons(ETHER_TYPE_IPv4)) {
>  		ipv4_hdr->hdr_checksum = 0;
> +		ol_flags |= PKT_TX_OUTER_IPV4;
> 
>  		if (testpmd_ol_flags & TESTPMD_TX_OFFLOAD_VXLAN_CKSUM)
>  			ol_flags |= PKT_TX_OUTER_IP_CKSUM;
> diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h index
> a554247..191a42c 100644
> --- a/lib/librte_mbuf/rte_mbuf.h
> +++ b/lib/librte_mbuf/rte_mbuf.h
> @@ -141,24 +141,53 @@ extern "C" {
>  #define PKT_TX_UDP_CKSUM     (3ULL << 52) /**< UDP cksum of TX pkt.
> computed by NIC. */
>  #define PKT_TX_L4_MASK       (3ULL << 52) /**< Mask for L4 cksum
> offload request. */
> 
> -#define PKT_TX_IP_CKSUM      (1ULL << 54) /**< IP cksum of TX pkt.
> computed by NIC. */
> +/**
> + * Offload the IP checksum in the hardware. The flag PKT_TX_IPV4 should
> + * also be set by the application, altough a PMD will only check
> + * PKT_TX_IP_CKSUM.
> + *  - set the IP checksum field in the packet to 0
> + *  - fill the mbuf offload information: l2_len, l3_len  */
> +#define PKT_TX_IP_CKSUM      (1ULL << 54)
> 
> -/** Packet is IPv4 without requiring IP checksum offload. */
> +/**
> + * Packet is IPv4. This flag must be set when using any offload feature
> + * (TSO, L3 or L4 checksum) to tell the NIC that the packet is an IPv4
> + * packet.
> + */
>  #define PKT_TX_IPV4          (1ULL << 55)
> 
> -/** Tell the NIC it's an IPv6 packet.*/
> +/**
> + * Packet is IPv6. This flag must be set when using an offload feature
> + * (TSO or L4 checksum) to tell the NIC that the packet is an IPv6
> + * packet.
> + */
>  #define PKT_TX_IPV6          (1ULL << 56)
Above two macro for IPV4/IPV6 will be used for inner L3 for tunneling case, right?
If yes, the annotations may need to mention that, to avoid confusing end users.

Regards,
Helin

> 
>  #define PKT_TX_VLAN_PKT      (1ULL << 57) /**< TX packet is a 802.1q
> VLAN packet. */
> 
> -/** Outer IP checksum of TX packet, computed by NIC for tunneling packet.
> - *  The tunnel type must also be specified, ex: PKT_TX_UDP_TUNNEL_PKT. */
> +/**
> + * Offload the IP checksum of an external header in the hardware. The
> + * flag PKT_TX_OUTER_IPV4 should also be set by the application,
> +altough
> + * a PMD will only check PKT_TX_IP_CKSUM.  The IP checksum field in the
> + * packet must be set to 0.
> + *  - set the outer IP checksum field in the packet to 0
> + *  - fill the mbuf offload information: outer_l2_len, outer_l3_len  */
>  #define PKT_TX_OUTER_IP_CKSUM   (1ULL << 58)
> 
> -/** Packet is outer IPv4 without requiring IP checksum offload for tunneling
> packet. */
> +/**
> + * Packet outer header is IPv4. This flag must be set when using any
> + * outer offload feature (L3 or L4 checksum) to tell the NIC that the
> + * packet is an IPv4 packet.
> + */
>  #define PKT_TX_OUTER_IPV4   (1ULL << 59)
> 
> -/** Tell the NIC it's an outer IPv6 packet for tunneling packet */
> +/**
> + * Packet outer header is IPv6. This flag must be set when using any
> + * outer offload feature (L4 checksum) to tell the NIC that the packet
> + * is an IPv6 packet.
> + */
>  #define PKT_TX_OUTER_IPV6    (1ULL << 60)
> 
>  /* Use final bit of flags to indicate a control mbuf */
> --
> 2.1.4