[dpdk-dev] Non-working TX IP checksum offload

[Angela Czubak]

Hi,

I have some difficulties using ip checksum tx offload capabilities - I 
think I set everything as advised by the API documentation, but 
unfortunately the packet leaves the interface with its ip checksum still 
being zero (it reaches its destination).

What I do is:
buffer->ol_flags |= PKT_TX_IP_CKSUM|PKT_TX_IPV4;
ip_header->hdr_checksum = 0;
buffer->l3_len = sizeof(struct ipv4_hdr);
buffer->l2_len = sizeof(struct ether_hdr);

In L4 there's UDP, which checksum is zeroed if that matters.

Is there something I am missing? The NIC is Intel Corporation Ethernet 
Controller X710 for 10GbE SFP+ (rev 01).

What is more, is there any particular reason for assuming in 
i40e_xmit_pkts that offloading checksums is unlikely (I mean the line no 
1307 "if (unlikely(ol_flags & I40E_TX_CKSUM_OFFLOAD_MASK))" at 
dpdk-2.0.0/lib/librte_pmd_i40e/i40e_rxtx.c)?

Regards,
Angela