bpf: cpumap: Implement XDP_REDIRECT for eBPF programs attached to map entries

Introduce XDP_REDIRECT support for eBPF programs attached to cpumap
entries.
This patch has been tested on Marvell ESPRESSObin using a modified
version of xdp_redirect_cpu sample in order to attach a XDP program
to CPUMAP entries to perform a redirect on the mvneta interface.
In particular the following scenario has been tested:

rq (cpu0) --> mvneta - XDP_REDIRECT (cpu0) --> CPUMAP - XDP_REDIRECT (cpu1) --> mvneta

$./xdp_redirect_cpu -p xdp_cpu_map0 -d eth0 -c 1 -e xdp_redirect \
	-f xdp_redirect_kern.o -m tx_port -r eth0

tx: 285.2 Kpps rx: 285.2 Kpps

Attaching a simple XDP program on eth0 to perform XDP_TX gives
comparable results:

tx: 288.4 Kpps rx: 288.4 Kpps

Co-developed-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Link: https://lore.kernel.org/bpf/2cf8373a731867af302b00c4ff16c122630c4980.1594734381.git.lorenzo@kernel.org

1 files changed, 1 insertions, 0 deletions

diff --git a/include/net/xdp.h b/include/net/xdp.h
index 83b9e0142b52..5be0d4d65b94 100644
--- a/include/net/xdp.h
+++ b/include/net/xdp.h
@@ -99,6 +99,7 @@ struct xdp_frame {
 };
 
 struct xdp_cpumap_stats {
+	unsigned int redirect;
 	unsigned int pass;
 	unsigned int drop;
 };