Commit de5bb438 authored by Zhengchao Shao's avatar Zhengchao Shao Committed by Andrii Nakryiko
Browse files

samples/bpf: Check detach prog exist or not in xdp_fwd 



Before detach the prog, we should check detach prog exist or not.

Signed-off-by: default avatarZhengchao Shao <shaozhengchao@huawei.com>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Reviewed-by: default avatarToke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20220606005425.261967-1-shaozhengchao@huawei.com
parent 3831cd1f

samples/bpf/xdp_fwd_user.c

+49 −6
Original line number Diff line number Diff line
@@ -47,17 +47,60 @@ static int do_attach(int idx, int prog_fd, int map_fd, const char *name) 
	return err;

}



static int do_detach(int idx, const char *name)

static int do_detach(int ifindex, const char *ifname, const char *app_name)

{

	int err;

	LIBBPF_OPTS(bpf_xdp_attach_opts, opts);

	struct bpf_prog_info prog_info = {};

	char prog_name[BPF_OBJ_NAME_LEN];

	__u32 info_len, curr_prog_id;

	int prog_fd;

	int err = 1;



	if (bpf_xdp_query_id(ifindex, xdp_flags, &curr_prog_id)) {

		printf("ERROR: bpf_xdp_query_id failed (%s)\n",

		       strerror(errno));

		return err;

	}



	err = bpf_xdp_detach(idx, xdp_flags, NULL);

	if (err < 0)

		printf("ERROR: failed to detach program from %s\n", name);

	if (!curr_prog_id) {

		printf("ERROR: flags(0x%x) xdp prog is not attached to %s\n",

		       xdp_flags, ifname);

		return err;

	}



	info_len = sizeof(prog_info);

	prog_fd = bpf_prog_get_fd_by_id(curr_prog_id);

	if (prog_fd < 0) {

		printf("ERROR: bpf_prog_get_fd_by_id failed (%s)\n",

		       strerror(errno));

		return prog_fd;

	}



	err = bpf_obj_get_info_by_fd(prog_fd, &prog_info, &info_len);

	if (err) {

		printf("ERROR: bpf_obj_get_info_by_fd failed (%s)\n",

		       strerror(errno));

		goto close_out;

	}

	snprintf(prog_name, sizeof(prog_name), "%s_prog", app_name);

	prog_name[BPF_OBJ_NAME_LEN - 1] = '\0';



	if (strcmp(prog_info.name, prog_name)) {

		printf("ERROR: %s isn't attached to %s\n", app_name, ifname);

		err = 1;

		goto close_out;

	}



	opts.old_prog_fd = prog_fd;

	err = bpf_xdp_detach(ifindex, xdp_flags, &opts);

	if (err < 0)

		printf("ERROR: failed to detach program from %s (%s)\n",

		       ifname, strerror(errno));

	/* TODO: Remember to cleanup map, when adding use of shared map

	 *  bpf_map_delete_elem((map_fd, &idx);

	 */

close_out:

	close(prog_fd);

	return err;

}
@@ -169,7 +212,7 @@ int main(int argc, char **argv) 
			return 1;

		}

		if (!attach) {

			err = do_detach(idx, argv[i]);

			err = do_detach(idx, argv[i], prog_name);

			if (err)

				ret = err;

		} else {