Commit 28b1520e authored by Lorenzo Bianconi's avatar Lorenzo Bianconi Committed by Daniel Borkmann
Browse files

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: default avatarJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: default avatarJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: default avatarLorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarJesper Dangaard Brouer <brouer@redhat.com>
Link: https://lore.kernel.org/bpf/2cf8373a731867af302b00c4ff16c122630c4980.1594734381.git.lorenzo@kernel.org
parent 92164774

include/net/xdp.h

+1 −0
Original line number Diff line number Diff line
@@ -99,6 +99,7 @@ struct xdp_frame { 
};



struct xdp_cpumap_stats {

	unsigned int redirect;

	unsigned int pass;

	unsigned int drop;

};

include/trace/events/xdp.h

+4 −2
Original line number Diff line number Diff line
@@ -190,6 +190,7 @@ TRACE_EVENT(xdp_cpumap_kthread, 
		__field(int, sched)

		__field(unsigned int, xdp_pass)

		__field(unsigned int, xdp_drop)

		__field(unsigned int, xdp_redirect)

	),



	TP_fast_assign(
@@ -201,18 +202,19 @@ TRACE_EVENT(xdp_cpumap_kthread, 
		__entry->sched	= sched;

		__entry->xdp_pass	= xdp_stats->pass;

		__entry->xdp_drop	= xdp_stats->drop;

		__entry->xdp_redirect	= xdp_stats->redirect;

	),



	TP_printk("kthread"

		  " cpu=%d map_id=%d action=%s"

		  " processed=%u drops=%u"

		  " sched=%d"

		  " xdp_pass=%u xdp_drop=%u",

		  " xdp_pass=%u xdp_drop=%u xdp_redirect=%u",

		  __entry->cpu, __entry->map_id,

		  __print_symbolic(__entry->act, __XDP_ACT_SYM_TAB),

		  __entry->processed, __entry->drops,

		  __entry->sched,

		  __entry->xdp_pass, __entry->xdp_drop)

		  __entry->xdp_pass, __entry->xdp_drop, __entry->xdp_redirect)

);



TRACE_EVENT(xdp_cpumap_enqueue,

kernel/bpf/cpumap.c

+15 −2
Original line number Diff line number Diff line
@@ -239,7 +239,7 @@ static int cpu_map_bpf_prog_run_xdp(struct bpf_cpu_map_entry *rcpu, 
	if (!rcpu->prog)

		return n;



	rcu_read_lock();

	rcu_read_lock_bh();



	xdp_set_return_frame_no_direct();

	xdp.rxq = &rxq;
@@ -267,6 +267,16 @@ static int cpu_map_bpf_prog_run_xdp(struct bpf_cpu_map_entry *rcpu, 
				stats->pass++;

			}

			break;

		case XDP_REDIRECT:

			err = xdp_do_redirect(xdpf->dev_rx, &xdp,

					      rcpu->prog);

			if (unlikely(err)) {

				xdp_return_frame(xdpf);

				stats->drop++;

			} else {

				stats->redirect++;

			}

			break;

		default:

			bpf_warn_invalid_xdp_action(act);

			/* fallthrough */
@@ -277,9 +287,12 @@ static int cpu_map_bpf_prog_run_xdp(struct bpf_cpu_map_entry *rcpu, 
		}

	}



	if (stats->redirect)

		xdp_do_flush_map();



	xdp_clear_return_frame_no_direct();



	rcu_read_unlock();

	rcu_read_unlock_bh(); /* resched point, may call do_softirq() */



	return nframes;

}