On Sun, 17 Jun 2018 14:55:06 +0530 Padam Jeet Singh <padam.si...@inventum.net> wrote:
> Hello, > > Issue observed when using vmxnet3 based interface on packet with following > structure is sent: > > Ethernet + PPPoE + PPP (22 bytes) as the Layer 2 header, > IPv4 (20) > UDP > DNS Payload > > The tx offload value in this case is 0x0f0000000000000 (PKT_TX_IPV4 | > PKT_TX_IP_CKSUM | PKT_TX_UDP_CKSUM) > > The checksum of the packet seen by the receiver shows incorrect checksum and > it’s value is the pseudo checksum value that was set at the time of the TX. > However the IP header checksum is correct. > > The same issue is not seen when the L2 header is a just the Ethernet (14 > bytes). > > Also, with the same setup on the same hardware if we switch the driver from > vmxnet3 to e1000e, all checksums are computed correctly. > > Is this a DPDK vmxnet3 driver bug or that of underlying esxi? The ESXi > version is 6.0.0 (Build 3620759). > > Thanks, > Padam I don't think VMWare supports IP checksum offload. Since IP checksum is trivial and in cache, the IP header checksum offload is usually not a speed up anyway. Linux for example, never does IP header checksum offload.
