[dpdk-users] DPDK KNI last 4 bytes of a frame truncated

[Pavan Kumar]

Hi,

I am trying to run example KNI application on Intel 82599ES 10-Gigabit. I see 
that the last 4 bytes of the frame are always truncated.
I did a quick dump of frame length in kni_ingress ().

pkts_burst[i]->pkt_len  = 268 bytes (Actual frame length from source is 272 
bytes)

I did a ip4 typecast of the received mbuf, it shows ip4->total_length is 254, 
which is 4 bytes less than actual data I send. Below is the sample code I used 
to dump ipv4 frame length.

if (rte_be_to_cpu_16(ether_type) == ETHER_TYPE_IPv4) {
            ip4 = rte_pktmbuf_mtod_offset(mbuf, struct ipv4_hdr *, hdr_len);
            hdr_len += sizeof(struct ipv4_hdr);
            l4_proto = ip4->next_proto_id;
            printf ("ip pkt len %d\n", rte_be_to_cpu_16(ip4->total_length));
}

I came across a similar post/ release notes for I350 controller (Ref: 
IXA00372461) which says CRC stripping is always enabled and results in last 4 
byte loss.
Is this a similar problem I am facing for 10G 82599 NIC using KNI ?

Thanks
Pavan

________________________________

DISCLAIMER:
This e-mail and any attachments to it may contain confidential and proprietary 
material and is solely for the use of the intended recipient. Any review, use, 
disclosure, distribution or copying of this transmittal is prohibited except by 
or on behalf of the intended recipient. If you have received this transmittal 
in error, please notify the sender and destroy this e-mail and any attachments 
and all copies, whether electronic or printed.