samples: bpf: Convert xdp_redirect_map_multi to XDP samples helper

Use the libbpf skeleton facility and other utilities provided by XDP
samples helper. Also adapt to change of type of mac address map, so that
no resizing is required.

Add a new flag for sample mask that skips priting the
from_device->to_device heading for each line, as xdp_redirect_map_multi
may have two devices but the flow of data may be bidirectional, so the
output would be confusing.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210821002010.845777-23-memxor@gmail.com

samples/bpf/Makefile

@@ -39,7 +39,6 @@ tprogs-y += lwt_len_hist
 tprogs-y += xdp_tx_iptunnel
 tprogs-y += test_map_in_map
 tprogs-y += per_socket_stats_example
-tprogs-y += xdp_redirect_map_multi
 tprogs-y += xdp_rxq_info
 tprogs-y += syscall_tp
 tprogs-y += cpustat
@@ -54,6 +53,7 @@ tprogs-y += ibumad
 tprogs-y += hbm
 
 tprogs-y += xdp_redirect_cpu
+tprogs-y += xdp_redirect_map_multi
 tprogs-y += xdp_redirect_map
 tprogs-y += xdp_redirect
 tprogs-y += xdp_monitor
@@ -100,7 +100,6 @@ lwt_len_hist-objs := lwt_len_hist_user.o
 xdp_tx_iptunnel-objs := xdp_tx_iptunnel_user.o
 test_map_in_map-objs := test_map_in_map_user.o
 per_socket_stats_example-objs := cookie_uid_helper_example.o
-xdp_redirect_map_multi-objs := xdp_redirect_map_multi_user.o
 xdp_rxq_info-objs := xdp_rxq_info_user.o
 syscall_tp-objs := syscall_tp_user.o
 cpustat-objs := cpustat_user.o
@@ -114,6 +113,7 @@ xdp_sample_pkts-objs := xdp_sample_pkts_user.o
 ibumad-objs := ibumad_user.o
 hbm-objs := hbm.o $(CGROUP_HELPERS)
 
+xdp_redirect_map_multi-objs := xdp_redirect_map_multi_user.o $(XDP_SAMPLE)
 xdp_redirect_cpu-objs := xdp_redirect_cpu_user.o $(XDP_SAMPLE)
 xdp_redirect_map-objs := xdp_redirect_map_user.o $(XDP_SAMPLE)
 xdp_redirect-objs := xdp_redirect_user.o $(XDP_SAMPLE)
@@ -310,6 +310,7 @@ $(BPF_SAMPLES_PATH)/*.c: verify_target_bpf $(LIBBPF)
 $(src)/*.c: verify_target_bpf $(LIBBPF)
 
 $(obj)/xdp_redirect_cpu_user.o: $(obj)/xdp_redirect_cpu.skel.h
+$(obj)/xdp_redirect_map_multi_user.o: $(obj)/xdp_redirect_map_multi.skel.h
 $(obj)/xdp_redirect_map_user.o: $(obj)/xdp_redirect_map.skel.h
 $(obj)/xdp_redirect_user.o: $(obj)/xdp_redirect.skel.h
 $(obj)/xdp_monitor_user.o: $(obj)/xdp_monitor.skel.h

samples/bpf/xdp_sample_user.c

@@ -1510,7 +1510,7 @@ static int sample_timer_cb(int timerfd, struct stats_record **rec,
 	if (ret < 0)
 		return ret;
 
-	if (sample_xdp_cnt == 2) {
+	if (sample_xdp_cnt == 2 && !(sample_mask & SAMPLE_SKIP_HEADING)) {
 		char fi[IFNAMSIZ];
 		char to[IFNAMSIZ];
 		const char *f, *t;

samples/bpf/xdp_sample_user.h

@@ -19,6 +19,7 @@ enum stats_mask {
 	SAMPLE_REDIRECT_MAP_CNT      = SAMPLE_REDIRECT_CNT | _SAMPLE_REDIRECT_MAP,
 	SAMPLE_REDIRECT_ERR_MAP_CNT  = SAMPLE_REDIRECT_ERR_CNT | _SAMPLE_REDIRECT_MAP,
 	SAMPLE_DEVMAP_XMIT_CNT_MULTI = 1U << 8,
+	SAMPLE_SKIP_HEADING	     = 1U << 9,
 };
 
 /* Exit return codes */