From 5ff051200308ab6f4c64c0fe52187bf4a1234dac Mon Sep 17 00:00:00 2001 From: Michal Rostecki Date: Wed, 8 Jan 2020 17:23:52 +0100 Subject: libbpf: Add probe for large INSN limit Introduce a new probe which checks whether kernel has large maximum program size which was increased in the following commit: c04c0d2b968a ("bpf: increase complexity limit and maximum program size") Based on the similar check in Cilium[0], authored by Daniel Borkmann. [0] https://github.com/cilium/cilium/commit/657d0f585afd26232cfa5d4e70b6f64d2ea91596 Co-authored-by: Daniel Borkmann Signed-off-by: Michal Rostecki Signed-off-by: Daniel Borkmann Reviewed-by: Quentin Monnet Link: https://lore.kernel.org/bpf/20200108162428.25014-2-mrostecki@opensuse.org --- tools/lib/bpf/libbpf_probes.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) (limited to 'tools/lib/bpf/libbpf_probes.c') diff --git a/tools/lib/bpf/libbpf_probes.c b/tools/lib/bpf/libbpf_probes.c index a9eb8b322671..221e6ad97012 100644 --- a/tools/lib/bpf/libbpf_probes.c +++ b/tools/lib/bpf/libbpf_probes.c @@ -321,3 +321,24 @@ bool bpf_probe_helper(enum bpf_func_id id, enum bpf_prog_type prog_type, return res; } + +/* + * Probe for availability of kernel commit (5.3): + * + * c04c0d2b968a ("bpf: increase complexity limit and maximum program size") + */ +bool bpf_probe_large_insn_limit(__u32 ifindex) +{ + struct bpf_insn insns[BPF_MAXINSNS + 1]; + int i; + + for (i = 0; i < BPF_MAXINSNS; i++) + insns[i] = BPF_MOV64_IMM(BPF_REG_0, 1); + insns[BPF_MAXINSNS] = BPF_EXIT_INSN(); + + errno = 0; + probe_load(BPF_PROG_TYPE_SCHED_CLS, insns, ARRAY_SIZE(insns), NULL, 0, + ifindex); + + return errno != E2BIG && errno != EINVAL; +} -- cgit v1.2.3-59-g8ed1b