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

-----Original Message-----
From: Olivier Matz [mailto:olivier.matz-pdR9zngts4EAvxtiuMwx3w@public.gmane.org]
Sent: Wednesday, February 4, 2015 5:25 PM
To: dev-VfR2kkLFssw@public.gmane.org
Cc: Ananyev, Konstantin; Liu, Jijiang; Zhang, Helin; olivier.matz@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 <redacted>
---
 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)