xdp: T2666: switch to example code provided by xdp-tutorial

1 files changed, 380 insertions, 0 deletions

diff --git a/src/xdp/common/common_user_bpf_xdp.c b/src/xdp/common/common_user_bpf_xdp.c
new file mode 100644
index 000000000..e7ef77174
--- /dev/null
+++ b/src/xdp/common/common_user_bpf_xdp.c
@@ -0,0 +1,380 @@
+#include <bpf/libbpf.h> /* bpf_get_link_xdp_id + bpf_set_link_xdp_id */
+#include <string.h>     /* strerror */
+#include <net/if.h>     /* IF_NAMESIZE */
+#include <stdlib.h>     /* exit(3) */
+#include <errno.h>
+
+#include <bpf/bpf.h>
+#include <bpf/libbpf.h>
+
+#include <linux/if_link.h> /* Need XDP flags */
+#include <linux/err.h>
+
+#include "common_defines.h"
+
+#ifndef PATH_MAX
+#define PATH_MAX	4096
+#endif
+
+int xdp_link_attach(int ifindex, __u32 xdp_flags, int prog_fd)
+{
+	int err;
+
+	/* libbpf provide the XDP net_device link-level hook attach helper */
+	err = bpf_set_link_xdp_fd(ifindex, prog_fd, xdp_flags);
+	if (err == -EEXIST && !(xdp_flags & XDP_FLAGS_UPDATE_IF_NOEXIST)) {
+		/* Force mode didn't work, probably because a program of the
+		 * opposite type is loaded. Let's unload that and try loading
+		 * again.
+		 */
+
+		__u32 old_flags = xdp_flags;
+
+		xdp_flags &= ~XDP_FLAGS_MODES;
+		xdp_flags |= (old_flags & XDP_FLAGS_SKB_MODE) ? XDP_FLAGS_DRV_MODE : XDP_FLAGS_SKB_MODE;
+		err = bpf_set_link_xdp_fd(ifindex, -1, xdp_flags);
+		if (!err)
+			err = bpf_set_link_xdp_fd(ifindex, prog_fd, old_flags);
+	}
+	if (err < 0) {
+		fprintf(stderr, "ERR: "
+			"ifindex(%d) link set xdp fd failed (%d): %s\n",
+			ifindex, -err, strerror(-err));
+
+		switch (-err) {
+		case EBUSY:
+		case EEXIST:
+			fprintf(stderr, "Hint: XDP already loaded on device"
+				" use --force to swap/replace\n");
+			break;
+		case EOPNOTSUPP:
+			fprintf(stderr, "Hint: Native-XDP not supported"
+				" use --skb-mode or --auto-mode\n");
+			break;
+		default:
+			break;
+		}
+		return EXIT_FAIL_XDP;
+	}
+
+	return EXIT_OK;
+}
+
+int xdp_link_detach(int ifindex, __u32 xdp_flags, __u32 expected_prog_id)
+{
+	__u32 curr_prog_id;
+	int err;
+
+	err = bpf_get_link_xdp_id(ifindex, &curr_prog_id, xdp_flags);
+	if (err) {
+		fprintf(stderr, "ERR: get link xdp id failed (err=%d): %s\n",
+			-err, strerror(-err));
+		return EXIT_FAIL_XDP;
+	}
+
+	if (!curr_prog_id) {
+		if (verbose)
+			printf("INFO: %s() no curr XDP prog on ifindex:%d\n",
+			       __func__, ifindex);
+		return EXIT_OK;
+	}
+
+	if (expected_prog_id && curr_prog_id != expected_prog_id) {
+		fprintf(stderr, "ERR: %s() "
+			"expected prog ID(%d) no match(%d), not removing\n",
+			__func__, expected_prog_id, curr_prog_id);
+		return EXIT_FAIL;
+	}
+
+	if ((err = bpf_set_link_xdp_fd(ifindex, -1, xdp_flags)) < 0) {
+		fprintf(stderr, "ERR: %s() link set xdp failed (err=%d): %s\n",
+			__func__, err, strerror(-err));
+		return EXIT_FAIL_XDP;
+	}
+
+	if (verbose)
+		printf("INFO: %s() removed XDP prog ID:%d on ifindex:%d\n",
+		       __func__, curr_prog_id, ifindex);
+
+	return EXIT_OK;
+}
+
+struct bpf_object *load_bpf_object_file(const char *filename, int ifindex)
+{
+	int first_prog_fd = -1;
+	struct bpf_object *obj;
+	int err;
+
+	/* This struct allow us to set ifindex, this features is used for
+	 * hardware offloading XDP programs (note this sets libbpf
+	 * bpf_program->prog_ifindex and foreach bpf_map->map_ifindex).
+	 */
+	struct bpf_prog_load_attr prog_load_attr = {
+		.prog_type = BPF_PROG_TYPE_XDP,
+		.ifindex   = ifindex,
+	};
+	prog_load_attr.file = filename;
+
+	/* Use libbpf for extracting BPF byte-code from BPF-ELF object, and
+	 * loading this into the kernel via bpf-syscall
+	 */
+	err = bpf_prog_load_xattr(&prog_load_attr, &obj, &first_prog_fd);
+	if (err) {
+		fprintf(stderr, "ERR: loading BPF-OBJ file(%s) (%d): %s\n",
+			filename, err, strerror(-err));
+		return NULL;
+	}
+
+	/* Notice how a pointer to a libbpf bpf_object is returned */
+	return obj;
+}
+
+static struct bpf_object *open_bpf_object(const char *file, int ifindex)
+{
+	int err;
+	struct bpf_object *obj;
+	struct bpf_map *map;
+	struct bpf_program *prog, *first_prog = NULL;
+
+	struct bpf_object_open_attr open_attr = {
+		.file = file,
+		.prog_type = BPF_PROG_TYPE_XDP,
+	};
+
+	obj = bpf_object__open_xattr(&open_attr);
+	if (IS_ERR_OR_NULL(obj)) {
+		err = -PTR_ERR(obj);
+		fprintf(stderr, "ERR: opening BPF-OBJ file(%s) (%d): %s\n",
+			file, err, strerror(-err));
+		return NULL;
+	}
+
+	bpf_object__for_each_program(prog, obj) {
+		bpf_program__set_type(prog, BPF_PROG_TYPE_XDP);
+		bpf_program__set_ifindex(prog, ifindex);
+		if (!first_prog)
+			first_prog = prog;
+	}
+
+	bpf_object__for_each_map(map, obj) {
+		if (!bpf_map__is_offload_neutral(map))
+			bpf_map__set_ifindex(map, ifindex);
+	}
+
+	if (!first_prog) {
+		fprintf(stderr, "ERR: file %s contains no programs\n", file);
+		return NULL;
+	}
+
+	return obj;
+}
+
+static int reuse_maps(struct bpf_object *obj, const char *path)
+{
+	struct bpf_map *map;
+
+	if (!obj)
+		return -ENOENT;
+
+	if (!path)
+		return -EINVAL;
+
+	bpf_object__for_each_map(map, obj) {
+		int len, err;
+		int pinned_map_fd;
+		char buf[PATH_MAX];
+
+		len = snprintf(buf, PATH_MAX, "%s/%s", path, bpf_map__name(map));
+		if (len < 0) {
+			return -EINVAL;
+		} else if (len >= PATH_MAX) {
+			return -ENAMETOOLONG;
+		}
+
+		pinned_map_fd = bpf_obj_get(buf);
+		if (pinned_map_fd < 0)
+			return pinned_map_fd;
+
+		err = bpf_map__reuse_fd(map, pinned_map_fd);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+struct bpf_object *load_bpf_object_file_reuse_maps(const char *file,
+						   int ifindex,
+						   const char *pin_dir)
+{
+	int err;
+	struct bpf_object *obj;
+
+	obj = open_bpf_object(file, ifindex);
+	if (!obj) {
+		fprintf(stderr, "ERR: failed to open object %s\n", file);
+		return NULL;
+	}
+
+	err = reuse_maps(obj, pin_dir);
+	if (err) {
+		fprintf(stderr, "ERR: failed to reuse maps for object %s, pin_dir=%s\n",
+				file, pin_dir);
+		return NULL;
+	}
+
+	err = bpf_object__load(obj);
+	if (err) {
+		fprintf(stderr, "ERR: loading BPF-OBJ file(%s) (%d): %s\n",
+			file, err, strerror(-err));
+		return NULL;
+	}
+
+	return obj;
+}
+
+struct bpf_object *load_bpf_and_xdp_attach(struct config *cfg)
+{
+	struct bpf_program *bpf_prog;
+	struct bpf_object *bpf_obj;
+	int offload_ifindex = 0;
+	int prog_fd = -1;
+	int err;
+
+	/* If flags indicate hardware offload, supply ifindex */
+	if (cfg->xdp_flags & XDP_FLAGS_HW_MODE)
+		offload_ifindex = cfg->ifindex;
+
+	/* Load the BPF-ELF object file and get back libbpf bpf_object */
+	if (cfg->reuse_maps)
+		bpf_obj = load_bpf_object_file_reuse_maps(cfg->filename,
+							  offload_ifindex,
+							  cfg->pin_dir);
+	else
+		bpf_obj = load_bpf_object_file(cfg->filename, offload_ifindex);
+	if (!bpf_obj) {
+		fprintf(stderr, "ERR: loading file: %s\n", cfg->filename);
+		exit(EXIT_FAIL_BPF);
+	}
+	/* At this point: All XDP/BPF programs from the cfg->filename have been
+	 * loaded into the kernel, and evaluated by the verifier. Only one of
+	 * these gets attached to XDP hook, the others will get freed once this
+	 * process exit.
+	 */
+
+	if (cfg->progsec[0])
+		/* Find a matching BPF prog section name */
+		bpf_prog = bpf_object__find_program_by_title(bpf_obj, cfg->progsec);
+	else
+		/* Find the first program */
+		bpf_prog = bpf_program__next(NULL, bpf_obj);
+
+	if (!bpf_prog) {
+		fprintf(stderr, "ERR: couldn't find a program in ELF section '%s'\n", cfg->progsec);
+		exit(EXIT_FAIL_BPF);
+	}
+
+	strncpy(cfg->progsec, bpf_program__title(bpf_prog, false), sizeof(cfg->progsec));
+
+	prog_fd = bpf_program__fd(bpf_prog);
+	if (prog_fd <= 0) {
+		fprintf(stderr, "ERR: bpf_program__fd failed\n");
+		exit(EXIT_FAIL_BPF);
+	}
+
+	/* At this point: BPF-progs are (only) loaded by the kernel, and prog_fd
+	 * is our select file-descriptor handle. Next step is attaching this FD
+	 * to a kernel hook point, in this case XDP net_device link-level hook.
+	 */
+	err = xdp_link_attach(cfg->ifindex, cfg->xdp_flags, prog_fd);
+	if (err)
+		exit(err);
+
+	return bpf_obj;
+}
+
+#define XDP_UNKNOWN	XDP_REDIRECT + 1
+#ifndef XDP_ACTION_MAX
+#define XDP_ACTION_MAX (XDP_UNKNOWN + 1)
+#endif
+
+static const char *xdp_action_names[XDP_ACTION_MAX] = {
+	[XDP_ABORTED]   = "XDP_ABORTED",
+	[XDP_DROP]      = "XDP_DROP",
+	[XDP_PASS]      = "XDP_PASS",
+	[XDP_TX]        = "XDP_TX",
+	[XDP_REDIRECT]  = "XDP_REDIRECT",
+	[XDP_UNKNOWN]	= "XDP_UNKNOWN",
+};
+
+const char *action2str(__u32 action)
+{
+        if (action < XDP_ACTION_MAX)
+                return xdp_action_names[action];
+        return NULL;
+}
+
+int check_map_fd_info(const struct bpf_map_info *info,
+		      const struct bpf_map_info *exp)
+{
+	if (exp->key_size && exp->key_size != info->key_size) {
+		fprintf(stderr, "ERR: %s() "
+			"Map key size(%d) mismatch expected size(%d)\n",
+			__func__, info->key_size, exp->key_size);
+		return EXIT_FAIL;
+	}
+	if (exp->value_size && exp->value_size != info->value_size) {
+		fprintf(stderr, "ERR: %s() "
+			"Map value size(%d) mismatch expected size(%d)\n",
+			__func__, info->value_size, exp->value_size);
+		return EXIT_FAIL;
+	}
+	if (exp->max_entries && exp->max_entries != info->max_entries) {
+		fprintf(stderr, "ERR: %s() "
+			"Map max_entries(%d) mismatch expected size(%d)\n",
+			__func__, info->max_entries, exp->max_entries);
+		return EXIT_FAIL;
+	}
+	if (exp->type && exp->type  != info->type) {
+		fprintf(stderr, "ERR: %s() "
+			"Map type(%d) mismatch expected type(%d)\n",
+			__func__, info->type, exp->type);
+		return EXIT_FAIL;
+	}
+
+	return 0;
+}
+
+int open_bpf_map_file(const char *pin_dir,
+		      const char *mapname,
+		      struct bpf_map_info *info)
+{
+	char filename[PATH_MAX];
+	int err, len, fd;
+	__u32 info_len = sizeof(*info);
+
+	len = snprintf(filename, PATH_MAX, "%s/%s", pin_dir, mapname);
+	if (len < 0) {
+		fprintf(stderr, "ERR: constructing full mapname path\n");
+		return -1;
+	}
+
+	fd = bpf_obj_get(filename);
+	if (fd < 0) {
+		fprintf(stderr,
+			"WARN: Failed to open bpf map file:%s err(%d):%s\n",
+			filename, errno, strerror(errno));
+		return fd;
+	}
+
+	if (info) {
+		err = bpf_obj_get_info_by_fd(fd, info, &info_len);
+		if (err) {
+			fprintf(stderr, "ERR: %s() can't get info - %s\n",
+				__func__,  strerror(errno));
+			return EXIT_FAIL_BPF;
+		}
+	}
+
+	return fd;
+}