[dpdk-dev] Regarding UDP checksum offload

[Prashant Upadhyaya]

Hi,

I am aware that this topic has been discussed several times before, but I
am somehow still stuck with this.

I am using dpdk 1.6r1, intel 82599 NIC.
I have an mbuf, I have hand-constructed a UDP packet (IPv4) in the data
portion, filled the relevant fields of the headers and I do a tx burst. No
problems, the destination gets the packet. I filled UDP checksum as zero
and there was no checksum offloaded in ol_flags.

Now in the same usecase, I want to offload UDP checksum.
I am aware that the checksum field in UDP header has to be filled with the
pseudo header checksum, I did that, duly added the PKT_TX_UDP_CKSUM flag in
ol_flags, did a tx_burst and the packet does not reach the destination.

I realized that I have to fill the following fields as well (my packet does
not have vlan tag)
mbuf->pkt.vlan_macip.f.l2_len
mbuf->pkt.vlan_macip.f.l3_len

so I filled the l2_len as 14 and l3_len as 20 (IP header with no options)
Yet the packet did not reach the destination.

So my question is -- am I filling the l2_len and l3_len properly ?
Is there anything else to be done before I can get this UDP checksum
offload to work properly for me.

Regards
-Prashant