[PATCH bpf-next 7/7] samples: bpf: convert some XDP samples from bpf_load to libbpf

[Jakub Kicinski <jakub.kicinski@netronome.com>]

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>
---
 samples/bpf/Makefile               |  8 +++---
 samples/bpf/xdp1_user.c            | 31 +++++++++++++-------
 samples/bpf/xdp_adjust_tail_user.c | 36 ++++++++++++++---------
 samples/bpf/xdp_rxq_info_user.c    | 46 ++++++++++++++++++++----------
 4 files changed, 78 insertions(+), 43 deletions(-)

diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 4f99de93d4db..7181b23226a7 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -78,9 +78,9 @@ test_cgrp2_attach-objs := test_cgrp2_attach.o $(LIBBPF)
 test_cgrp2_attach2-objs := test_cgrp2_attach2.o $(LIBBPF) $(CGROUP_HELPERS)
 test_cgrp2_sock-objs := test_cgrp2_sock.o $(LIBBPF)
 test_cgrp2_sock2-objs := bpf_load.o $(LIBBPF) test_cgrp2_sock2.o
-xdp1-objs := bpf_load.o $(LIBBPF) xdp1_user.o
+xdp1-objs := xdp1_user.o $(LIBBPF)
 # reuse xdp1 source intentionally
-xdp2-objs := bpf_load.o $(LIBBPF) xdp1_user.o
+xdp2-objs := xdp1_user.o $(LIBBPF)
 xdp_router_ipv4-objs := bpf_load.o $(LIBBPF) xdp_router_ipv4_user.o
 test_current_task_under_cgroup-objs := bpf_load.o $(LIBBPF) $(CGROUP_HELPERS) \
 				       test_current_task_under_cgroup_user.o
@@ -95,10 +95,10 @@ xdp_redirect-objs := bpf_load.o $(LIBBPF) xdp_redirect_user.o
 xdp_redirect_map-objs := bpf_load.o $(LIBBPF) xdp_redirect_map_user.o
 xdp_redirect_cpu-objs := bpf_load.o $(LIBBPF) xdp_redirect_cpu_user.o
 xdp_monitor-objs := bpf_load.o $(LIBBPF) xdp_monitor_user.o
-xdp_rxq_info-objs := bpf_load.o $(LIBBPF) xdp_rxq_info_user.o
+xdp_rxq_info-objs := xdp_rxq_info_user.o $(LIBBPF)
 syscall_tp-objs := bpf_load.o $(LIBBPF) syscall_tp_user.o
 cpustat-objs := bpf_load.o $(LIBBPF) cpustat_user.o
-xdp_adjust_tail-objs := bpf_load.o $(LIBBPF) xdp_adjust_tail_user.o
+xdp_adjust_tail-objs := xdp_adjust_tail_user.o $(LIBBPF)
 xdpsock-objs := bpf_load.o $(LIBBPF) xdpsock_user.o
 
 # Tell kbuild to always build the programs
diff --git a/samples/bpf/xdp1_user.c b/samples/bpf/xdp1_user.c
index b901ee2b3336..b02c531510ed 100644
--- a/samples/bpf/xdp1_user.c
+++ b/samples/bpf/xdp1_user.c
@@ -16,9 +16,9 @@
 #include <libgen.h>
 #include <sys/resource.h>
 
-#include "bpf_load.h"
 #include "bpf_util.h"
-#include "libbpf.h"
+#include "bpf/bpf.h"
+#include "bpf/libbpf.h"
 
 static int ifindex;
 static __u32 xdp_flags;
@@ -31,7 +31,7 @@ static void int_exit(int sig)
 
 /* simple per-protocol drop counter
  */
-static void poll_stats(int interval)
+static void poll_stats(int map_fd, int interval)
 {
 	unsigned int nr_cpus = bpf_num_possible_cpus();
 	const unsigned int nr_keys = 256;
@@ -47,7 +47,7 @@ static void poll_stats(int interval)
 		for (key = 0; key < nr_keys; key++) {
 			__u64 sum = 0;
 
-			assert(bpf_map_lookup_elem(map_fd[0], &key, values) == 0);
+			assert(bpf_map_lookup_elem(map_fd, &key, values) == 0);
 			for (i = 0; i < nr_cpus; i++)
 				sum += (values[i] - prev[key][i]);
 			if (sum)
@@ -71,9 +71,14 @@ static void usage(const char *prog)
 int main(int argc, char **argv)
 {
 	struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
+	struct bpf_prog_load_attr prog_load_attr = {
+		.prog_type	= BPF_PROG_TYPE_XDP,
+	};
 	const char *optstr = "SN";
+	int prog_fd, map_fd, opt;
+	struct bpf_object *obj;
+	struct bpf_map *map;
 	char filename[256];
-	int opt;
 
 	while ((opt = getopt(argc, argv, optstr)) != -1) {
 		switch (opt) {
@@ -102,13 +107,19 @@ int main(int argc, char **argv)
 	ifindex = strtoul(argv[optind], NULL, 0);
 
 	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+	prog_load_attr.file = filename;
 
-	if (load_bpf_file(filename)) {
-		printf("%s", bpf_log_buf);
+	if (bpf_prog_load_xattr(&prog_load_attr, &obj, &prog_fd))
+		return 1;
+
+	map = bpf_map__next(NULL, obj);
+	if (!map) {
+		printf("finding a map in obj file failed\n");
 		return 1;
 	}
+	map_fd = bpf_map__fd(map);
 
-	if (!prog_fd[0]) {
+	if (!prog_fd) {
 		printf("load_bpf_file: %s\n", strerror(errno));
 		return 1;
 	}
@@ -116,12 +127,12 @@ int main(int argc, char **argv)
 	signal(SIGINT, int_exit);
 	signal(SIGTERM, 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) {
 		printf("link set xdp fd failed\n");
 		return 1;
 	}
 
-	poll_stats(2);
+	poll_stats(map_fd, 2);
 
 	return 0;
 }
diff --git a/samples/bpf/xdp_adjust_tail_user.c b/samples/bpf/xdp_adjust_tail_user.c
index f621a541b574..3042ce37dae8 100644
--- a/samples/bpf/xdp_adjust_tail_user.c
+++ b/samples/bpf/xdp_adjust_tail_user.c
@@ -18,9 +18,8 @@
 #include <netinet/ether.h>
 #include <unistd.h>
 #include <time.h>
-#include "bpf_load.h"
-#include "libbpf.h"
-#include "bpf_util.h"
+#include "bpf/bpf.h"
+#include "bpf/libbpf.h"
 
 #define STATS_INTERVAL_S 2U
 
@@ -36,7 +35,7 @@ static void int_exit(int sig)
 
 /* simple "icmp packet too big sent" counter
  */
-static void poll_stats(unsigned int kill_after_s)
+static void poll_stats(unsigned int map_fd, unsigned int kill_after_s)
 {
 	time_t started_at = time(NULL);
 	__u64 value = 0;
@@ -46,7 +45,7 @@ static void poll_stats(unsigned int kill_after_s)
 	while (!kill_after_s || time(NULL) - started_at <= kill_after_s) {
 		sleep(STATS_INTERVAL_S);
 
-		assert(bpf_map_lookup_elem(map_fd[0], &key, &value) == 0);
+		assert(bpf_map_lookup_elem(map_fd, &key, &value) == 0);
 
 		printf("icmp \"packet too big\" sent: %10llu pkts\n", value);
 	}
@@ -66,14 +65,17 @@ static void usage(const char *cmd)
 
 int main(int argc, char **argv)
 {
+	struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
+	struct bpf_prog_load_attr prog_load_attr = {
+		.prog_type	= BPF_PROG_TYPE_XDP,
+	};
 	unsigned char opt_flags[256] = {};
 	unsigned int kill_after_s = 0;
 	const char *optstr = "i:T:SNh";
-	struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
+	int i, prog_fd, map_fd, opt;
+	struct bpf_object *obj;
+	struct bpf_map *map;
 	char filename[256];
-	int opt;
-	int i;
-
 
 	for (i = 0; i < strlen(optstr); i++)
 		if (optstr[i] != 'h' && 'a' <= optstr[i] && optstr[i] <= 'z')
@@ -115,13 +117,19 @@ int main(int argc, char **argv)
 	}
 
 	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+	prog_load_attr.file = filename;
+
+	if (bpf_prog_load_xattr(&prog_load_attr, &obj, &prog_fd))
+		return 1;
 
-	if (load_bpf_file(filename)) {
-		printf("%s", bpf_log_buf);
+	map = bpf_map__next(NULL, obj);
+	if (!map) {
+		printf("finding a map in obj file failed\n");
 		return 1;
 	}
+	map_fd = bpf_map__fd(map);
 
-	if (!prog_fd[0]) {
+	if (!prog_fd) {
 		printf("load_bpf_file: %s\n", strerror(errno));
 		return 1;
 	}
@@ -129,12 +137,12 @@ int main(int argc, char **argv)
 	signal(SIGINT, int_exit);
 	signal(SIGTERM, 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) {
 		printf("link set xdp fd failed\n");
 		return 1;
 	}
 
-	poll_stats(kill_after_s);
+	poll_stats(map_fd, kill_after_s);
 
 	bpf_set_link_xdp_fd(ifindex, -1, xdp_flags);
 
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;
 	}
-- 
2.17.0