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bpftool: Refactor misc. feature probe

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There is currently a single miscellaneous feature probe,
HAVE_LARGE_INSN_LIMIT, to check for the 1M instructions limit in the
verifier. Subsequent patches will add additional miscellaneous probes,
which follow the same pattern at the existing probe. This patch
therefore refactors the probe to avoid code duplication in subsequent
patches.

The BPF program type and the checked error numbers in the
HAVE_LARGE_INSN_LIMIT probe are changed to better generalize to other
probes. The feature probe retains its current behavior despite those
changes.

Signed-off-by: Paul Chaignon <paul@isovalent.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/956c9329a932c75941194f91790d01f31dfbe01b.1641314075.git.paul@isovalent.com
This commit is contained in:
Paul Chaignon 2022-01-04 18:59:29 +01:00 committed by Daniel Borkmann
parent c5bcdd8228
commit b22bf1b997
1 changed files with 29 additions and 16 deletions
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45
tools/bpf/bpftool/feature.c
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@ -642,6 +642,30 @@ probe_helpers_for_progtype(enum bpf_prog_type prog_type, bool supported_type,
printf("\n");
}
static void
probe_misc_feature(struct bpf_insn *insns, size_t len,
const char *define_prefix, __u32 ifindex,
const char *feat_name, const char *plain_name,
const char *define_name)
{
LIBBPF_OPTS(bpf_prog_load_opts, opts,
.prog_ifindex = ifindex,
);
bool res;
int fd;
errno = 0;
fd = bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, NULL, "GPL",
insns, len, &opts);
res = fd >= 0 || !errno;
if (fd >= 0)
close(fd);
print_bool_feature(feat_name, plain_name, define_name, res,
define_prefix);
}
/*
* Probe for availability of kernel commit (5.3):
*
@ -649,29 +673,18 @@ probe_helpers_for_progtype(enum bpf_prog_type prog_type, bool supported_type,
*/
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;
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;
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);
print_bool_feature("have_large_insn_limit",
probe_misc_feature(insns, ARRAY_SIZE(insns),
define_prefix, ifindex,
"have_large_insn_limit",
"Large program size limit",
"LARGE_INSN_LIMIT",
res, define_prefix);
"LARGE_INSN_LIMIT");
}
static void