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

[Liu, Jijiang]

Hi Olivier,

> -----Original Message-----
> From: Zhang, Helin
> Sent: Tuesday, February 10, 2015 1:39 PM
> To: Olivier Matz; dev at dpdk.org
> Cc: Ananyev, Konstantin; Liu, Jijiang
> Subject: RE: [PATCH v2 02/20] mbuf: enhance the API documentation of offload
> flags
> 
> 
> 
> > -----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;
> >

Look at the codes again, you should extend process_outer_cksums() to support other tunneling packet.

The code changes like below,
process_outer_cksums(void *outer_l3_hdr, struct testpmd_offload_info *info,
uint16_t testpmd_ol_flags, uint16_t l4_proto)  // add the l4_proto parameter here.
...
        /* outer UDP checksum is always done in software as we have no
         * hardware supporting it today, and no API for it. */
      if (l4_proto == IPPROTO_UDP)
	   udp_hdr = (struct udp_hdr *)((char *)outer_l3_hdr + info->outer_l3_len);
        	/* do not recalculate udp cksum if it was 0 */
        	if (udp_hdr->dgram_cksum != 0) {
                	udp_hdr->dgram_cksum = 0;
                	if (info->outer_ethertype == _htons(ETHER_TYPE_IPv4))
                        	udp_hdr->dgram_cksum =
                              	  rte_ipv4_udptcp_cksum(ipv4_hdr, udp_hdr);
                else
                        udp_hdr->dgram_cksum =
                                rte_ipv6_udptcp_cksum(ipv6_hdr, udp_hdr);
            }
      }  // nothing need to do for GRE tunneling packet now
}


> >  		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