DPDK 之 TX-Offload Checksum
計算 IP checksum
mb->l2_len = len(out_eth)
mb->l3_len = len(out_ip)
mb->ol_flags |= PKT_TX_IPV4 | PKT_TX_IP_CSUM注:
out_ip.checksum = 0
網卡支持 DEV_TX_OFFLOAD_IPV4_CKSUM 特性.
計算 IP & UDP checksum
mb->l2_len = len(out_eth)
mb->l3_len = len(out_ip)
mb->ol_flags |= PKT_TX_IPV4 | PKT_TX_IP_CSUM | PKT_TX_UDP_CKSUM注:
out_ip.checksum = 0
out_udp.checksum = rte_ipv4_phdr_cksum()
網卡支持 DEV_TX_OFFLOAD_IPV4_CKSUM and DEV_TX_OFFLOAD_UDP_CKSUM 特性.
計算內層封裝 ip checksum.
mb->l2_len = len(out_eth + out_ip + out_udp + vxlan + in_eth)
mb->l3_len = len(in_ip)
mb->ol_flags |= PKT_TX_IPV4 | PKT_TX_IP_CSUM注:
in_ip.checksum = 0
網卡支持 DEV_TX_OFFLOAD_IPV4_CKSUM` 特性.
Note that it can only work if outer L4 checksum is 0.
計算內層封裝 IP & TCP checksum
mb->l2_len = len(out_eth + out_ip + out_udp + vxlan + in_eth)
mb->l3_len = len(in_ip)
mb->ol_flags |= PKT_TX_IPV4 | PKT_TX_IP_CSUM | PKT_TX_TCP_CKSUM注:
in_ip.checksum = 0
in_tcp.checksum = rte_ipv4_phdr_cksum()
網卡支持 DEV_TX_OFFLOAD_IPV4_CKSUM and DEV_TX_OFFLOAD_TCP_CKSUM 特性.
Note that it can only work if outer L4 checksum is 0.
計算內層封裝 ip checksum 並啓用 tso.
mb->l2_len = len(out_eth + out_ip + out_udp + vxlan + in_eth)
mb->l3_len = len(in_ip)
mb->l4_len = len(in_tcp)
mb->ol_flags |= PKT_TX_IPV4 | PKT_TX_IP_CKSUM | PKT_TX_TCP_CKSUM |
PKT_TX_TCP_SEG;注:
in_ip.checksum = 0
in_tcp.checksum = rte_ipv4_phdr_cksum()
網卡支持 DEV_TX_OFFLOAD_TCP_TSO 特性.
Note that it can only work if outer L4 checksum is 0.
計算內層 ip & 內存封裝 ip & tcp checksum .
mb->outer_l2_len = len(out_eth)
mb->outer_l3_len = len(out_ip)
mb->l2_len = len(out_udp + vxlan + in_eth)
mb->l3_len = len(in_ip)
mb->ol_flags |= PKT_TX_OUTER_IPV4 | PKT_TX_OUTER_IP_CKSUM | \
PKT_TX_IP_CKSUM | PKT_TX_TCP_CKSUM;
注:
out_ip.checksum = 0
in_ip.checksum = 0
in_tcp.checksum = rte_ipv4_phdr_cksum()
網卡支持 DEV_TX_OFFLOAD_IPV4_CKSUM, DEV_TX_OFFLOAD_UDP_CKSUM and DEV_TX_OFFLOAD_OUTER_IPV4_CKSUM 特性.