Add new probes to test what eBPF program types are available on the
system. For each type, try loading a very simple program of that type
and see if the verifier complains.
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,
...
}
}
# bpftool feature probe kernel macros prefix BPFTOOL_
...
/*** eBPF program types ***/
#define BPFTOOL_SOCKET_FILTER_PROG_TYPE
#define BPFTOOL_KPROBE_PROG_TYPE
#define BPFTOOL_SCHED_CLS_PROG_TYPE
...
Signed-off-by: Quentin Monnet <quentin.mon...@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicin...@netronome.com>
---
tools/bpf/bpftool/feature.c | 102 +++++++++++++++++++++++++++++++++++-
1 file changed, 100 insertions(+), 2 deletions(-)
diff --git a/tools/bpf/bpftool/feature.c b/tools/bpf/bpftool/feature.c
index 4a3a45f44162..4910c9c325d6 100644
--- a/tools/bpf/bpftool/feature.c
+++ b/tools/bpf/bpftool/feature.c
@@ -1,6 +1,7 @@
// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
/* Copyright (c) 2018 Netronome Systems, Inc. */
+#include <ctype.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
@@ -37,6 +38,14 @@ static bool check_procfs(void)
return true;
}
+static void uppercase(char *str, size_t len)
+{
+ size_t i;
+
+ for (i = 0; i < len && str[i] != '\0'; i++)
+ str[i] = toupper(str[i]);
+}
+
/* Printing utility functions */
static void
@@ -97,6 +106,19 @@ print_start_section(const char *json_title, const char
*define_comment,
}
}
+static void
+print_end_then_start_section(const char *json_title, const char *define_title,
+ const char *plain_title, const char *define_prefix)
+{
+ if (json_output)
+ jsonw_end_object(json_wtr);
+ else
+ printf("\n");
+
+ print_start_section(json_title, define_title, plain_title,
+ define_prefix);
+}
+
/* Probing functions */
static int read_procfs(const char *path)
@@ -480,10 +502,73 @@ static bool probe_bpf_syscall(const char *define_prefix)
return res;
}
+static void
+prog_load(enum bpf_prog_type prog_type, const struct bpf_insn *insns,
+ size_t insns_cnt, int kernel_version, char *buf, size_t buf_len)
+{
+ struct bpf_load_program_attr xattr = {};
+ int fd;
+
+ switch (prog_type) {
+ case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
+ xattr.expected_attach_type = BPF_CGROUP_INET4_CONNECT;
+ break;
+ default:
+ break;
+ }
+
+ xattr.prog_type = prog_type;
+ xattr.insns = insns;
+ xattr.insns_cnt = insns_cnt;
+ xattr.license = "GPL";
+ xattr.kern_version = kernel_version;
+
+ fd = bpf_load_program_xattr(&xattr, buf, buf_len);
+ if (fd >= 0)
+ close(fd);
+}
+
+static void
+probe_prog_type(enum bpf_prog_type prog_type, int kernel_version,
+ bool *supported_types, const char *define_prefix)
+{
+ char buf[4096], feat_name[128], define_name[128], plain_desc[128];
+ const char *plain_comment = "eBPF program_type ";
+ struct bpf_insn insns[2] = {
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN()
+ };
+ size_t maxlen;
+ bool res;
+
+ errno = 0;
+ prog_load(prog_type, insns, ARRAY_SIZE(insns), kernel_version,
+ buf, sizeof(buf));
+ res = (errno != EINVAL && errno != EOPNOTSUPP);
+
+ supported_types[prog_type] |= res;
+
+ maxlen = sizeof(plain_desc) - strlen(plain_comment) - 1;
+ if (strlen(prog_type_name[prog_type]) > maxlen) {
+ p_info("program type name too long");
+ return;
+ }
+
+ sprintf(feat_name, "have_%s_prog_type", prog_type_name[prog_type]);
+ sprintf(define_name, "%s_prog_type", prog_type_name[prog_type]);
+ uppercase(define_name, sizeof(define_name));
+ sprintf(plain_desc, "%s%s", plain_comment, prog_type_name[prog_type]);
+ print_bool_feature(feat_name, define_name, plain_desc, res,
+ define_prefix);
+}
+
static int do_probe(int argc, char **argv)
{
enum probe_component target = COMPONENT_UNSPEC;
const char *define_prefix = NULL;
+ bool supported_types[128] = {};
+ int kernel_version;
+ unsigned int i;
/* Detection assumes user has sufficient privileges (CAP_SYS_ADMIN).
* Let's approximate, and restrict usage to root user only.
@@ -558,9 +643,22 @@ static int do_probe(int argc, char **argv)
"Scanning system call and kernel version...",
define_prefix);
- probe_kernel_version(define_prefix);
- probe_bpf_syscall(define_prefix);
+ kernel_version = probe_kernel_version(define_prefix);
+ if (!probe_bpf_syscall(define_prefix))
+ /* bpf() syscall unavailable, don't probe other BPF features */
+ goto exit_close_json;
+
+ print_end_then_start_section("program_types",
+ "/*** eBPF program types ***/",
+ "Scanning eBPF program types...",
+ define_prefix);
+
+ for (i = BPF_PROG_TYPE_SOCKET_FILTER;
+ i < ARRAY_SIZE(prog_type_name); i++)
+ probe_prog_type(i, kernel_version, supported_types,
+ define_prefix);
+exit_close_json:
if (json_output) {
/* End current "section" of probes */
jsonw_end_object(json_wtr);
--
2.17.1
