From: Michal Rostecki <mrostecki@opensuse.org>
Date: Wed, 8 Jan 2020 17:23:52 +0100
Subject: libbpf: Add probe for large INSN limit
Patch-mainline: v5.6-rc1
Git-commit: 5ff051200308ab6f4c64c0fe52187bf4a1234dac
References: bsc#1177028
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 <daniel@iogearbox.net>
Signed-off-by: Michal Rostecki <mrostecki@opensuse.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Link: https://lore.kernel.org/bpf/20200108162428.25014-2-mrostecki@opensuse.org
Acked-by: Gary Lin <glin@suse.com>
---
tools/lib/bpf/libbpf.h | 1 +
tools/lib/bpf/libbpf.map | 1 +
tools/lib/bpf/libbpf_probes.c | 21 +++++++++++++++++++++
3 files changed, 23 insertions(+)
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -548,6 +548,7 @@ LIBBPF_API bool bpf_probe_prog_type(enum
LIBBPF_API bool bpf_probe_map_type(enum bpf_map_type map_type, __u32 ifindex);
LIBBPF_API bool bpf_probe_helper(enum bpf_func_id id,
enum bpf_prog_type prog_type, __u32 ifindex);
+LIBBPF_API bool bpf_probe_large_insn_limit(__u32 ifindex);
/*
* Get bpf_prog_info in continuous memory
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -218,6 +218,7 @@ LIBBPF_0.0.7 {
bpf_object__detach_skeleton;
bpf_object__load_skeleton;
bpf_object__open_skeleton;
+ bpf_probe_large_insn_limit;
bpf_prog_attach_xattr;
bpf_program__attach;
bpf_program__name;
--- 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 i
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;
+}