samples: bpf: convert some XDP samples from bpf_load to libbpf

Now that we can use full powers of libbpf in BPF samples, we
should perhaps make the simplest XDP programs not depend on
bpf_load helpers.  This way newcomers will be exposed to the
recommended library from the start.

Use of bpf_prog_load_xattr() will also make it trivial to later
on request offload of the programs by simply adding ifindex to
the xattr.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

1 files changed, 31 insertions, 15 deletions

diff --git a/samples/bpf/xdp_rxq_info_user.c b/samples/bpf/xdp_rxq_info_user.c
index 478d95412de4..e4e9ba52bff0 100644
--- a/samples/bpf/xdp_rxq_info_user.c
+++ b/samples/bpf/xdp_rxq_info_user.c
@@ -22,8 +22,8 @@ static const char *__doc__ = " XDP RX-queue info extract example\n\n"
 #include <arpa/inet.h>
 #include <linux/if_link.h>
 
-#include "libbpf.h"
-#include "bpf_load.h"
+#include "bpf/bpf.h"
+#include "bpf/libbpf.h"
 #include "bpf_util.h"
 
 static int ifindex = -1;
@@ -32,6 +32,9 @@ static char *ifname;
 
 static __u32 xdp_flags;
 
+static struct bpf_map *stats_global_map;
+static struct bpf_map *rx_queue_index_map;
+
 /* Exit return codes */
 #define EXIT_OK		0
 #define EXIT_FAIL		1
@@ -174,7 +177,7 @@ static struct datarec *alloc_record_per_cpu(void)
 
 static struct record *alloc_record_per_rxq(void)
 {
-	unsigned int nr_rxqs = map_data[2].def.max_entries;
+	unsigned int nr_rxqs = bpf_map__def(rx_queue_index_map)->max_entries;
 	struct record *array;
 	size_t size;
 
@@ -190,7 +193,7 @@ static struct record *alloc_record_per_rxq(void)
 
 static struct stats_record *alloc_stats_record(void)
 {
-	unsigned int nr_rxqs = map_data[2].def.max_entries;
+	unsigned int nr_rxqs = bpf_map__def(rx_queue_index_map)->max_entries;
 	struct stats_record *rec;
 	int i;
 
@@ -210,7 +213,7 @@ static struct stats_record *alloc_stats_record(void)
 
 static void free_stats_record(struct stats_record *r)
 {
-	unsigned int nr_rxqs = map_data[2].def.max_entries;
+	unsigned int nr_rxqs = bpf_map__def(rx_queue_index_map)->max_entries;
 	int i;
 
 	for (i = 0; i < nr_rxqs; i++)
@@ -254,11 +257,11 @@ static void stats_collect(struct stats_record *rec)
 {
 	int fd, i, max_rxqs;
 
-	fd = map_data[1].fd; /* map: stats_global_map */
+	fd = bpf_map__fd(stats_global_map);
 	map_collect_percpu(fd, 0, &rec->stats);
 
-	fd = map_data[2].fd; /* map: rx_queue_index_map */
-	max_rxqs = map_data[2].def.max_entries;
+	fd = bpf_map__fd(rx_queue_index_map);
+	max_rxqs = bpf_map__def(rx_queue_index_map)->max_entries;
 	for (i = 0; i < max_rxqs; i++)
 		map_collect_percpu(fd, i, &rec->rxq[i]);
 }
@@ -304,8 +307,8 @@ static void stats_print(struct stats_record *stats_rec,
 			struct stats_record *stats_prev,
 			int action)
 {
+	unsigned int nr_rxqs = bpf_map__def(rx_queue_index_map)->max_entries;
 	unsigned int nr_cpus = bpf_num_possible_cpus();
-	unsigned int nr_rxqs = map_data[2].def.max_entries;
 	double pps = 0, err = 0;
 	struct record *rec, *prev;
 	double t;
@@ -419,31 +422,44 @@ static void stats_poll(int interval, int action)
 int main(int argc, char **argv)
 {
 	struct rlimit r = {10 * 1024 * 1024, RLIM_INFINITY};
+	struct bpf_prog_load_attr prog_load_attr = {
+		.prog_type	= BPF_PROG_TYPE_XDP,
+	};
+	int prog_fd, map_fd, opt, err;
 	bool use_separators = true;
 	struct config cfg = { 0 };
+	struct bpf_object *obj;
+	struct bpf_map *map;
 	char filename[256];
 	int longindex = 0;
 	int interval = 2;
 	__u32 key = 0;
-	int opt, err;
 
 	char action_str_buf[XDP_ACTION_MAX_STRLEN + 1 /* for \0 */] = { 0 };
 	int action = XDP_PASS; /* Default action */
 	char *action_str = NULL;
 
 	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+	prog_load_attr.file = filename;
 
 	if (setrlimit(RLIMIT_MEMLOCK, &r)) {
 		perror("setrlimit(RLIMIT_MEMLOCK)");
 		return 1;
 	}
 
-	if (load_bpf_file(filename)) {
-		fprintf(stderr, "ERR in load_bpf_file(): %s", bpf_log_buf);
+	if (bpf_prog_load_xattr(&prog_load_attr, &obj, &prog_fd))
+		return EXIT_FAIL;
+
+	map = bpf_map__next(NULL, obj);
+	stats_global_map = bpf_map__next(map, obj);
+	rx_queue_index_map = bpf_map__next(stats_global_map, obj);
+	if (!map || !stats_global_map || !rx_queue_index_map) {
+		printf("finding a map in obj file failed\n");
 		return EXIT_FAIL;
 	}
+	map_fd = bpf_map__fd(map);
 
-	if (!prog_fd[0]) {
+	if (!prog_fd) {
 		fprintf(stderr, "ERR: load_bpf_file: %s\n", strerror(errno));
 		return EXIT_FAIL;
 	}
@@ -512,7 +528,7 @@ int main(int argc, char **argv)
 		setlocale(LC_NUMERIC, "en_US");
 
 	/* User-side setup ifindex in config_map */
-	err = bpf_map_update_elem(map_fd[0], &key, &cfg, 0);
+	err = bpf_map_update_elem(map_fd, &key, &cfg, 0);
 	if (err) {
 		fprintf(stderr, "Store config failed (err:%d)\n", err);
 		exit(EXIT_FAIL_BPF);
@@ -521,7 +537,7 @@ int main(int argc, char **argv)
 	/* Remove XDP program when program is interrupted */
 	signal(SIGINT, int_exit);
 
-	if (bpf_set_link_xdp_fd(ifindex, prog_fd[0], xdp_flags) < 0) {
+	if (bpf_set_link_xdp_fd(ifindex, prog_fd, xdp_flags) < 0) {
 		fprintf(stderr, "link set xdp fd failed\n");
 		return EXIT_FAIL_XDP;
 	}