Commit e967a20a authored by Andrii Nakryiko's avatar Andrii Nakryiko Committed by Daniel Borkmann
Browse files

bpftool: Reimplement large insn size limit feature probing 



Reimplement bpf_probe_large_insn_limit() in bpftool, as that libbpf API
is scheduled for deprecation in v0.8.

Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarDave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/bpf/20211217171202.3352835-4-andrii@kernel.org
parent 5a8ea82f

tools/bpf/bpftool/feature.c

+23 −3
Original line number Diff line number Diff line
@@ -642,12 +642,32 @@ probe_helpers_for_progtype(enum bpf_prog_type prog_type, bool supported_type, 
		printf("\n");

}



static void

probe_large_insn_limit(const char *define_prefix, __u32 ifindex)

/*

 * Probe for availability of kernel commit (5.3):

 *

 * c04c0d2b968a ("bpf: increase complexity limit and maximum program size")

 */

static void probe_large_insn_limit(const char *define_prefix, __u32 ifindex)

{

	LIBBPF_OPTS(bpf_prog_load_opts, opts,

		.prog_ifindex = ifindex,

	);

	struct bpf_insn insns[BPF_MAXINSNS + 1];

	bool res;

	int i, fd;



	for (i = 0; i < BPF_MAXINSNS; i++)

		insns[i] = BPF_MOV64_IMM(BPF_REG_0, 1);

	insns[BPF_MAXINSNS] = BPF_EXIT_INSN();



	errno = 0;

	fd = bpf_prog_load(BPF_PROG_TYPE_SCHED_CLS, NULL, "GPL",

			   insns, ARRAY_SIZE(insns), &opts);

	res = fd >= 0 || (errno != E2BIG && errno != EINVAL);



	if (fd >= 0)

		close(fd);



	res = bpf_probe_large_insn_limit(ifindex);

	print_bool_feature("have_large_insn_limit",

			   "Large program size limit",

			   "LARGE_INSN_LIMIT",