[dpdk-users] AF_PACKET pmd and linux networking stack

[Andrew Wang <andrw.wng@gmail.com>]

Hi

Is there a way of preventing the linux kernel networking stack from
handling packets when using the AF_PACKET pmd?

Our DPDK app is running on a node that is attracting traffic for a VIP and
for which it has a blackhole routing rule (to drop all the incoming packets
for that VIP).

The intention was to have our DPDK app (running on AF_PACKET pmd for now -
we're still developing the app) grab those packets, process and send them
out (with a different address).

Right now we can actually see those packets in our dpdk app, we process
them, give them a different address, but it seems that the linux kernel
networking stack is still dropping them.

When the blackhole rule is removed we see the outgoing packet with correct
header, but also a destination unreachable message is sent out, suggesting
the kernel is also handling the packet. We see the same behavior when using
iptables to drop packets (instead of blackhole route).

Any suggestions appreciated.

Thanks
Andrew