Merge branch 'bpf-convert-more-samples'

Jakub Kicinski says:

====================
This set converts xdpsock_user.c and xdp_fwd_user.c to use libbpf instead
of bpf_load.o.  First two patches are minor improvements to libbpf to make
the conversion (and use of libbpf in general) nicer.
====================

Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

samples/bpf/Makefile

@@ -105,8 +105,8 @@ xdp_rxq_info-objs := xdp_rxq_info_user.o
 syscall_tp-objs := bpf_load.o syscall_tp_user.o
 cpustat-objs := bpf_load.o cpustat_user.o
 xdp_adjust_tail-objs := xdp_adjust_tail_user.o
-xdpsock-objs := bpf_load.o xdpsock_user.o
-xdp_fwd-objs := bpf_load.o xdp_fwd_user.o
+xdpsock-objs := xdpsock_user.o
+xdp_fwd-objs := xdp_fwd_user.o
 task_fd_query-objs := bpf_load.o task_fd_query_user.o $(TRACE_HELPERS)
 xdp_sample_pkts-objs := xdp_sample_pkts_user.o $(TRACE_HELPERS)
 

samples/bpf/xdp_fwd_user.c

@@ -24,8 +24,7 @@
 #include <fcntl.h>
 #include <libgen.h>
 
-#include "bpf_load.h"
-#include "bpf_util.h"
+#include "bpf/libbpf.h"
 #include <bpf/bpf.h>
 
 
@@ -63,9 +62,15 @@ static void usage(const char *prog)
 
 int main(int argc, char **argv)
 {
+	struct bpf_prog_load_attr prog_load_attr = {
+		.prog_type	= BPF_PROG_TYPE_XDP,
+	};
+	const char *prog_name = "xdp_fwd";
+	struct bpf_program *prog;
 	char filename[PATH_MAX];
+	struct bpf_object *obj;
 	int opt, i, idx, err;
-	int prog_id = 0;
+	int prog_fd, map_fd;
 	int attach = 1;
 	int ret = 0;
 
@@ -75,7 +80,7 @@ int main(int argc, char **argv)
 			attach = 0;
 			break;
 		case 'D':
-			prog_id = 1;
+			prog_name = "xdp_fwd_direct";
 			break;
 		default:
 			usage(basename(argv[0]));
@@ -90,6 +95,7 @@ int main(int argc, char **argv)
 
 	if (attach) {
 		snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+		prog_load_attr.file = filename;
 
 		if (access(filename, O_RDONLY) < 0) {
 			printf("error accessing file %s: %s\n",
@@ -97,19 +103,25 @@ int main(int argc, char **argv)
 			return 1;
 		}
 
-		if (load_bpf_file(filename)) {
-			printf("%s", bpf_log_buf);
+		if (bpf_prog_load_xattr(&prog_load_attr, &obj, &prog_fd))
+			return 1;
+
+		prog = bpf_object__find_program_by_title(obj, prog_name);
+		prog_fd = bpf_program__fd(prog);
+		if (prog_fd < 0) {
+			printf("program not found: %s\n", strerror(prog_fd));
 			return 1;
 		}
-
-		if (!prog_fd[prog_id]) {
-			printf("load_bpf_file: %s\n", strerror(errno));
+		map_fd = bpf_map__fd(bpf_object__find_map_by_name(obj,
+								  "tx_port"));
+		if (map_fd < 0) {
+			printf("map not found: %s\n", strerror(map_fd));
 			return 1;
 		}
 	}
 	if (attach) {
 		for (i = 1; i < 64; ++i)
-			bpf_map_update_elem(map_fd[0], &i, &i, 0);
+			bpf_map_update_elem(map_fd, &i, &i, 0);
 	}
 
 	for (i = optind; i < argc; ++i) {
@@ -126,7 +138,7 @@ int main(int argc, char **argv)
 			if (err)
 				ret = err;
 		} else {
-			err = do_attach(idx, prog_fd[prog_id], argv[i]);
+			err = do_attach(idx, prog_fd, argv[i]);
 			if (err)
 				ret = err;
 		}

samples/bpf/xdpsock_user.c

@@ -26,7 +26,7 @@
 #include <sys/types.h>
 #include <poll.h>
 
-#include "bpf_load.h"
+#include "bpf/libbpf.h"
 #include "bpf_util.h"
 #include <bpf/bpf.h>
 
@@ -891,7 +891,13 @@ static void l2fwd(struct xdpsock *xsk)
 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,
+	};
+	int prog_fd, qidconf_map, xsks_map;
+	struct bpf_object *obj;
 	char xdp_filename[256];
+	struct bpf_map *map;
 	int i, ret, key = 0;
 	pthread_t pt;
 
@@ -904,24 +910,38 @@ int main(int argc, char **argv)
 	}
 
 	snprintf(xdp_filename, sizeof(xdp_filename), "%s_kern.o", argv[0]);
+	prog_load_attr.file = xdp_filename;
 
-	if (load_bpf_file(xdp_filename)) {
-		fprintf(stderr, "ERROR: load_bpf_file %s\n", bpf_log_buf);
+	if (bpf_prog_load_xattr(&prog_load_attr, &obj, &prog_fd))
+		exit(EXIT_FAILURE);
+	if (prog_fd < 0) {
+		fprintf(stderr, "ERROR: no program found: %s\n",
+			strerror(prog_fd));
 		exit(EXIT_FAILURE);
 	}
 
-	if (!prog_fd[0]) {
-		fprintf(stderr, "ERROR: load_bpf_file: \"%s\"\n",
-			strerror(errno));
+	map = bpf_object__find_map_by_name(obj, "qidconf_map");
+	qidconf_map = bpf_map__fd(map);
+	if (qidconf_map < 0) {
+		fprintf(stderr, "ERROR: no qidconf map found: %s\n",
+			strerror(qidconf_map));
 		exit(EXIT_FAILURE);
 	}
 
-	if (bpf_set_link_xdp_fd(opt_ifindex, prog_fd[0], opt_xdp_flags) < 0) {
+	map = bpf_object__find_map_by_name(obj, "xsks_map");
+	xsks_map = bpf_map__fd(map);
+	if (xsks_map < 0) {
+		fprintf(stderr, "ERROR: no xsks map found: %s\n",
+			strerror(xsks_map));
+		exit(EXIT_FAILURE);
+	}
+
+	if (bpf_set_link_xdp_fd(opt_ifindex, prog_fd, opt_xdp_flags) < 0) {
 		fprintf(stderr, "ERROR: link set xdp fd failed\n");
 		exit(EXIT_FAILURE);
 	}
 
-	ret = bpf_map_update_elem(map_fd[0], &key, &opt_queue, 0);
+	ret = bpf_map_update_elem(qidconf_map, &key, &opt_queue, 0);
 	if (ret) {
 		fprintf(stderr, "ERROR: bpf_map_update_elem qidconf\n");
 		exit(EXIT_FAILURE);
@@ -938,7 +958,7 @@ int main(int argc, char **argv)
 	/* ...and insert them into the map. */
 	for (i = 0; i < num_socks; i++) {
 		key = i;
-		ret = bpf_map_update_elem(map_fd[1], &key, &xsks[i]->sfd, 0);
+		ret = bpf_map_update_elem(xsks_map, &key, &xsks[i]->sfd, 0);
 		if (ret) {
 			fprintf(stderr, "ERROR: bpf_map_update_elem %d\n", i);
 			exit(EXIT_FAILURE);

tools/lib/bpf/libbpf.c

@@ -873,6 +873,18 @@ bpf_object__find_prog_by_idx(struct bpf_object *obj, int idx)
 	return NULL;
 }
 
+struct bpf_program *
+bpf_object__find_program_by_title(struct bpf_object *obj, const char *title)
+{
+	struct bpf_program *pos;
+
+	bpf_object__for_each_program(pos, obj) {
+		if (pos->section_name && !strcmp(pos->section_name, title))
+			return pos;
+	}
+	return NULL;
+}
+
 static int
 bpf_program__collect_reloc(struct bpf_program *prog, GElf_Shdr *shdr,
 			   Elf_Data *data, struct bpf_object *obj)
@@ -1991,6 +2003,9 @@ int bpf_program__nth_fd(struct bpf_program *prog, int n)
 {
 	int fd;
 
+	if (!prog)
+		return -EINVAL;
+
 	if (n >= prog->instances.nr || n < 0) {
 		pr_warning("Can't get the %dth fd from program %s: only %d instances\n",
 			   n, prog->section_name, prog->instances.nr);

tools/lib/bpf/libbpf.h

@@ -86,6 +86,9 @@ const char *bpf_object__name(struct bpf_object *obj);
 unsigned int bpf_object__kversion(struct bpf_object *obj);
 int bpf_object__btf_fd(const struct bpf_object *obj);
 
+struct bpf_program *
+bpf_object__find_program_by_title(struct bpf_object *obj, const char *title);
+
 struct bpf_object *bpf_object__next(struct bpf_object *prev);
 #define bpf_object__for_each_safe(pos, tmp)			\
 	for ((pos) = bpf_object__next(NULL),		\