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https://github.com/Fishwaldo/linux-bl808.git
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1bf4b05810
Introduce probes for supported BPF program types in libbpf, and call it
from bpftool to test what types are available on the system. The probe
simply consists in loading a very basic program of that type and see if
the verifier complains or not.
Sample output:
# bpftool feature probe kernel
...
Scanning eBPF program types...
eBPF program_type socket_filter is available
eBPF program_type kprobe is available
eBPF program_type sched_cls is available
...
# bpftool --json --pretty feature probe kernel
{
...
"program_types": {
"have_socket_filter_prog_type": true,
"have_kprobe_prog_type": true,
"have_sched_cls_prog_type": true,
...
}
}
v5:
- In libbpf.map, move global symbol to a new LIBBPF_0.0.2 section.
- Rename (non-API function) prog_load() as probe_load().
v3:
- Get kernel version for checking kprobes availability from libbpf
instead of from bpftool. Do not pass kernel_version as an argument
when calling libbpf probes.
- Use a switch with all enum values for setting specific program
parameters just before probing, so that gcc complains at compile time
(-Wswitch-enum) if new prog types were added to the kernel but libbpf
was not updated.
- Add a comment in libbpf.h about setrlimit() usage to allow many
consecutive probe attempts.
v2:
- Move probes from bpftool to libbpf.
- Remove C-style macros output from this patch.
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
95 lines
2.3 KiB
C
95 lines
2.3 KiB
C
// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
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/* Copyright (c) 2019 Netronome Systems, Inc. */
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#include <errno.h>
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#include <unistd.h>
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#include <sys/utsname.h>
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#include <linux/filter.h>
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#include <linux/kernel.h>
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#include "bpf.h"
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#include "libbpf.h"
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static int get_kernel_version(void)
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{
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int version, subversion, patchlevel;
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struct utsname utsn;
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/* Return 0 on failure, and attempt to probe with empty kversion */
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if (uname(&utsn))
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return 0;
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if (sscanf(utsn.release, "%d.%d.%d",
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&version, &subversion, &patchlevel) != 3)
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return 0;
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return (version << 16) + (subversion << 8) + patchlevel;
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}
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static void
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probe_load(enum bpf_prog_type prog_type, const struct bpf_insn *insns,
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size_t insns_cnt, char *buf, size_t buf_len, __u32 ifindex)
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{
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struct bpf_load_program_attr xattr = {};
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int fd;
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switch (prog_type) {
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case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
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xattr.expected_attach_type = BPF_CGROUP_INET4_CONNECT;
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break;
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case BPF_PROG_TYPE_KPROBE:
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xattr.kern_version = get_kernel_version();
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break;
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case BPF_PROG_TYPE_UNSPEC:
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case BPF_PROG_TYPE_SOCKET_FILTER:
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case BPF_PROG_TYPE_SCHED_CLS:
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case BPF_PROG_TYPE_SCHED_ACT:
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case BPF_PROG_TYPE_TRACEPOINT:
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case BPF_PROG_TYPE_XDP:
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case BPF_PROG_TYPE_PERF_EVENT:
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case BPF_PROG_TYPE_CGROUP_SKB:
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case BPF_PROG_TYPE_CGROUP_SOCK:
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case BPF_PROG_TYPE_LWT_IN:
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case BPF_PROG_TYPE_LWT_OUT:
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case BPF_PROG_TYPE_LWT_XMIT:
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case BPF_PROG_TYPE_SOCK_OPS:
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case BPF_PROG_TYPE_SK_SKB:
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case BPF_PROG_TYPE_CGROUP_DEVICE:
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case BPF_PROG_TYPE_SK_MSG:
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case BPF_PROG_TYPE_RAW_TRACEPOINT:
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case BPF_PROG_TYPE_LWT_SEG6LOCAL:
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case BPF_PROG_TYPE_LIRC_MODE2:
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case BPF_PROG_TYPE_SK_REUSEPORT:
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case BPF_PROG_TYPE_FLOW_DISSECTOR:
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default:
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break;
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}
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xattr.prog_type = prog_type;
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xattr.insns = insns;
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xattr.insns_cnt = insns_cnt;
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xattr.license = "GPL";
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xattr.prog_ifindex = ifindex;
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fd = bpf_load_program_xattr(&xattr, buf, buf_len);
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if (fd >= 0)
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close(fd);
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}
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bool bpf_probe_prog_type(enum bpf_prog_type prog_type, __u32 ifindex)
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{
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struct bpf_insn insns[2] = {
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_EXIT_INSN()
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};
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if (ifindex && prog_type == BPF_PROG_TYPE_SCHED_CLS)
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/* nfp returns -EINVAL on exit(0) with TC offload */
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insns[0].imm = 2;
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errno = 0;
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probe_load(prog_type, insns, ARRAY_SIZE(insns), NULL, 0, ifindex);
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return errno != EINVAL && errno != EOPNOTSUPP;
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}
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