Describe how to use hardware checksum API. Signed-off-by: Olivier Matz <olivier.matz at 6wind.com> --- lib/librte_mbuf/rte_mbuf.h | 25 +++++++++++++++++-------- 1 file changed, 17 insertions(+), 8 deletions(-)
diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h index be15168..96e322b 100644 --- a/lib/librte_mbuf/rte_mbuf.h +++ b/lib/librte_mbuf/rte_mbuf.h @@ -95,19 +95,28 @@ extern "C" { #define PKT_RX_TUNNEL_IPV6_HDR (1ULL << 12) /**< RX tunnel packet with IPv6 header. */ #define PKT_TX_VLAN_PKT (1ULL << 55) /**< TX packet is a 802.1q VLAN packet. */ -#define PKT_TX_IP_CKSUM (1ULL << 54) /**< IP cksum of TX pkt. computed by NIC. */ + +/** + * Enable hardware computation of IP cksum. To use it: + * - fill l2_len and l3_len in mbuf + * - set the flags PKT_TX_IP_CKSUM + * - set the ip checksum to 0 in IP header + */ +#define PKT_TX_IP_CKSUM (1ULL << 54) #define PKT_TX_IPV4_CSUM PKT_TX_IP_CKSUM /**< Alias of PKT_TX_IP_CKSUM. */ #define PKT_TX_IPV4 PKT_RX_IPV4_HDR /**< IPv4 with no IP checksum offload. */ #define PKT_TX_IPV6 PKT_RX_IPV6_HDR /**< IPv6 packet */ -/* - * Bits 52+53 used for L4 packet type with checksum enabled. - * 00: Reserved - * 01: TCP checksum - * 10: SCTP checksum - * 11: UDP checksum +/** + * Bits 52+53 used for L4 packet type with checksum enabled: 00: Reserved, + * 01: TCP checksum, 10: SCTP checksum, 11: UDP checksum. To use hardware + * L4 checksum offload, the user needs to: + * - fill l2_len and l3_len in mbuf + * - set the flags PKT_TX_TCP_CKSUM, PKT_TX_SCTP_CKSUM or PKT_TX_UDP_CKSUM + * - calculate the pseudo header checksum and set it in the L4 header (only + * for TCP or UDP). For SCTP, set the crc field to 0. */ -#define PKT_TX_L4_NO_CKSUM (0ULL << 52) /**< Disable L4 cksum of TX pkt. */ +#define PKT_TX_L4_NO_CKSUM (0ULL << 52) /* Disable L4 cksum of TX pkt. */ #define PKT_TX_TCP_CKSUM (1ULL << 52) /**< TCP cksum of TX pkt. computed by NIC. */ #define PKT_TX_SCTP_CKSUM (2ULL << 52) /**< SCTP cksum of TX pkt. computed by NIC. */ #define PKT_TX_UDP_CKSUM (3ULL << 52) /**< UDP cksum of TX pkt. computed by NIC. */ -- 2.1.0