Thanks Helin, The "fix" below works for me but I don't think it's complete and correct for all kernels.
Daniel Index: src/kernel/fast_kni/kni_net.c =================================================================== --- src/kernel/fast_kni/kni_net.c +++ src/kernel/fast_kni/kni_net.c @@ -353,6 +353,12 @@ kni->stats.rx_bytes += len; kni->stats.rx_packets++; + /* adjust the skb */ + if (likely(skb_mac_header_was_set(skb))) { + skb->len += ETH_HLEN; + skb->data -= ETH_HLEN; + } + /* call tx interface */ kni_net_tx(skb, dev); } On Wed, Dec 25, 2013 at 2:50 AM, Zhang, Helin <helin.zhang at intel.com> wrote: > Hi Daniel > > Thanks for your good catch! > Yes. That's a bug, and it will be fixed in later DPDK releases. > > Regards, > Helin > > -----Original Message----- > From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Daniel Kaminsky > Sent: Friday, December 20, 2013 12:36 AM > To: dev at dpdk.org > Subject: [dpdk-dev] Loop back mode of the KNI > > Hi all, > > We're working on the KNI and we see a strange behavior which seems like a > bug in the the kernel module. > > When running with *lo_mode=lo_mode_fifo *everything works as expected, the > packets looks similar on the ingress and egress. > But when running with *lo_mode=lo_mode_fifo_skb *the packets on the egress > doesn't include the first 14 bytes (the ethernet header) although the > packets size doesn't change. > > Thanks, > Daniel >