Similarly to what was done for program types and map types, add a set of
probes to test the availability of the different eBPF helper functions
on the current system.
Sample output:
# bpftool feature probe kernel
...
Scanning eBPF helper functions...
eBPF helper bpf_map_lookup_elem is available
eBPF helper bpf_map_update_elem is available
eBPF helper bpf_map_delete_elem is available
...
# bpftool --json --pretty feature probe kernel
{
...
"helpers": {
"have_bpf_map_lookup_elem_helper": true,
"have_bpf_map_update_elem_helper": true,
"have_bpf_map_delete_elem_helper": true,
...
}
}
# bpftool feature probe kernel macros prefix BPFTOOL_
...
/*** eBPF helper functions ***/
#define BPFTOOL_BPF_MAP_LOOKUP_ELEM_HELPER
#define BPFTOOL_BPF_MAP_UPDATE_ELEM_HELPER
#define BPFTOOL_BPF_MAP_DELETE_ELEM_HELPER
...
Signed-off-by: Quentin Monnet <quentin.mon...@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicin...@netronome.com>
---
.../bpftool/Documentation/bpftool-feature.rst | 4 +
tools/bpf/bpftool/feature.c | 152 ++++++++++++++++++
2 files changed, 156 insertions(+)
diff --git a/tools/bpf/bpftool/Documentation/bpftool-feature.rst
b/tools/bpf/bpftool/Documentation/bpftool-feature.rst
index 23920a7490e9..083d30510cce 100644
--- a/tools/bpf/bpftool/Documentation/bpftool-feature.rst
+++ b/tools/bpf/bpftool/Documentation/bpftool-feature.rst
@@ -39,6 +39,10 @@ DESCRIPTION
names when including the output of this command as a header
file.
+ Note that when probed, some eBPF helpers (e.g.
+ **bpf_trace_printk**\ () or **bpf_probe_write_user**\ ()) may
+ print warnings to kernel logs.
+
**bpftool feature help**
Print short help message.
diff --git a/tools/bpf/bpftool/feature.c b/tools/bpf/bpftool/feature.c
index 85928f172413..77221fff6ba9 100644
--- a/tools/bpf/bpftool/feature.c
+++ b/tools/bpf/bpftool/feature.c
@@ -24,6 +24,113 @@ enum probe_component {
COMPONENT_KERNEL,
};
+#define MAX_HELPER_NAME_LEN 32
+struct helper_param {
+ enum bpf_prog_type progtype;
+ const char name[MAX_HELPER_NAME_LEN];
+};
+
+/* helper_progtype_and_name[index] associates to the BPF helper function of id
+ * "index" a name and a program type to run this helper with. In order to probe
+ * helper availability for programs offloaded to a network device, use
+ * offload-compatible types (e.g. XDP) everywhere we can. Caveats: helper
+ * probing may fail currently if only TC (but not XDP) is supported for
+ * offload.
+ */
+static const struct helper_param helper_progtype_and_name[] = {
+ { BPF_PROG_TYPE_XDP, "no_helper_with_id_0" },
+ { BPF_PROG_TYPE_XDP, "bpf_map_lookup_elem" },
+ { BPF_PROG_TYPE_XDP, "bpf_map_update_elem" },
+ { BPF_PROG_TYPE_XDP, "bpf_map_delete_elem" },
+ { BPF_PROG_TYPE_KPROBE, "bpf_probe_read" },
+ { BPF_PROG_TYPE_XDP, "bpf_ktime_get_ns" },
+ { BPF_PROG_TYPE_XDP, "bpf_trace_printk" },
+ { BPF_PROG_TYPE_XDP, "bpf_get_prandom_u32" },
+ { BPF_PROG_TYPE_XDP, "bpf_get_smp_processor_id" },
+ { BPF_PROG_TYPE_SCHED_CLS, "bpf_skb_store_bytes" },
+ { BPF_PROG_TYPE_SCHED_CLS, "bpf_l3_csum_replace" },
+ { BPF_PROG_TYPE_SCHED_CLS, "bpf_l4_csum_replace" },
+ { BPF_PROG_TYPE_XDP, "bpf_tail_call" },
+ { BPF_PROG_TYPE_SCHED_CLS, "bpf_clone_redirect" },
+ { BPF_PROG_TYPE_KPROBE, "bpf_get_current_pid_tgid" },
+ { BPF_PROG_TYPE_KPROBE, "bpf_get_current_uid_gid" },
+ { BPF_PROG_TYPE_KPROBE, "bpf_get_current_comm" },
+ { BPF_PROG_TYPE_SCHED_CLS, "bpf_get_cgroup_classid" },
+ { BPF_PROG_TYPE_SCHED_CLS, "bpf_skb_vlan_push" },
+ { BPF_PROG_TYPE_SCHED_CLS, "bpf_skb_vlan_pop" },
+ { BPF_PROG_TYPE_SCHED_CLS, "bpf_skb_get_tunnel_key" },
+ { BPF_PROG_TYPE_SCHED_CLS, "bpf_skb_set_tunnel_key" },
+ { BPF_PROG_TYPE_KPROBE, "bpf_perf_event_read" },
+ { BPF_PROG_TYPE_XDP, "bpf_redirect" },
+ { BPF_PROG_TYPE_SCHED_CLS, "bpf_get_route_realm" },
+ { BPF_PROG_TYPE_XDP, "bpf_perf_event_output" },
+ { BPF_PROG_TYPE_SCHED_CLS, "bpf_skb_load_bytes" },
+ { BPF_PROG_TYPE_KPROBE, "bpf_get_stackid" },
+ { BPF_PROG_TYPE_XDP, "bpf_csum_diff" },
+ { BPF_PROG_TYPE_SCHED_CLS, "bpf_skb_get_tunnel_opt" },
+ { BPF_PROG_TYPE_SCHED_CLS, "bpf_skb_set_tunnel_opt" },
+ { BPF_PROG_TYPE_SCHED_CLS, "bpf_skb_change_proto" },
+ { BPF_PROG_TYPE_SCHED_CLS, "bpf_skb_change_type" },
+ { BPF_PROG_TYPE_SCHED_CLS, "bpf_skb_under_cgroup" },
+ { BPF_PROG_TYPE_SCHED_CLS, "bpf_get_hash_recalc" },
+ { BPF_PROG_TYPE_KPROBE, "bpf_get_current_task" },
+ { BPF_PROG_TYPE_KPROBE, "bpf_probe_write_user" },
+ { BPF_PROG_TYPE_KPROBE, "bpf_current_task_under_cgroup" },
+ { BPF_PROG_TYPE_SCHED_CLS, "bpf_skb_change_tail" },
+ { BPF_PROG_TYPE_SCHED_CLS, "bpf_skb_pull_data" },
+ { BPF_PROG_TYPE_SCHED_CLS, "bpf_csum_update" },
+ { BPF_PROG_TYPE_SCHED_CLS, "bpf_set_hash_invalid" },
+ { BPF_PROG_TYPE_XDP, "bpf_get_numa_node_id" },
+ { BPF_PROG_TYPE_SK_SKB, "bpf_skb_change_head" },
+ { BPF_PROG_TYPE_XDP, "bpf_xdp_adjust_head" },
+ { BPF_PROG_TYPE_KPROBE, "bpf_probe_read_str" },
+ { BPF_PROG_TYPE_SCHED_CLS, "bpf_get_socket_cookie" },
+ { BPF_PROG_TYPE_SCHED_CLS, "bpf_get_socket_uid" },
+ { BPF_PROG_TYPE_SCHED_CLS, "bpf_set_hash" },
+ { BPF_PROG_TYPE_SOCK_OPS, "bpf_setsockopt" },
+ { BPF_PROG_TYPE_SCHED_CLS, "bpf_skb_adjust_room" },
+ { BPF_PROG_TYPE_XDP, "bpf_redirect_map" },
+ { BPF_PROG_TYPE_SK_SKB, "bpf_sk_redirect_map" },
+ { BPF_PROG_TYPE_SOCK_OPS, "bpf_sock_map_update" },
+ { BPF_PROG_TYPE_XDP, "bpf_xdp_adjust_meta" },
+ { BPF_PROG_TYPE_KPROBE, "bpf_perf_event_read_value" },
+ { BPF_PROG_TYPE_PERF_EVENT, "bpf_perf_prog_read_value" },
+ { BPF_PROG_TYPE_SOCK_OPS, "bpf_getsockopt" },
+ { BPF_PROG_TYPE_KPROBE, "bpf_override_return" },
+ { BPF_PROG_TYPE_SOCK_OPS, "bpf_sock_ops_cb_flags_set" },
+ { BPF_PROG_TYPE_SK_MSG, "bpf_msg_redirect_map" },
+ { BPF_PROG_TYPE_SK_MSG, "bpf_msg_apply_bytes" },
+ { BPF_PROG_TYPE_SK_MSG, "bpf_msg_cork_bytes" },
+ { BPF_PROG_TYPE_SK_MSG, "bpf_msg_pull_data" },
+ { BPF_PROG_TYPE_CGROUP_SOCK_ADDR, "bpf_bind" },
+ { BPF_PROG_TYPE_XDP, "bpf_xdp_adjust_tail" },
+ { BPF_PROG_TYPE_SCHED_CLS, "bpf_skb_get_xfrm_state" },
+ { BPF_PROG_TYPE_KPROBE, "bpf_get_stack" },
+ { BPF_PROG_TYPE_SCHED_CLS, "bpf_skb_load_bytes_relative" },
+ { BPF_PROG_TYPE_SCHED_CLS, "bpf_fib_lookup" },
+ { BPF_PROG_TYPE_SOCK_OPS, "bpf_sock_hash_update" },
+ { BPF_PROG_TYPE_SK_MSG, "bpf_msg_redirect_hash" },
+ { BPF_PROG_TYPE_SK_SKB, "bpf_sk_redirect_hash" },
+ { BPF_PROG_TYPE_LWT_IN, "bpf_lwt_push_encap" },
+ { BPF_PROG_TYPE_LWT_SEG6LOCAL, "bpf_lwt_seg6_store_bytes" },
+ { BPF_PROG_TYPE_LWT_SEG6LOCAL, "bpf_lwt_seg6_adjust_srh" },
+ { BPF_PROG_TYPE_LWT_SEG6LOCAL, "bpf_lwt_seg6_action" },
+ { BPF_PROG_TYPE_LIRC_MODE2, "bpf_rc_repeat" },
+ { BPF_PROG_TYPE_LIRC_MODE2, "bpf_rc_keydown" },
+ { BPF_PROG_TYPE_SCHED_CLS, "bpf_skb_cgroup_id" },
+ { BPF_PROG_TYPE_KPROBE, "bpf_get_current_cgroup_id" },
+ { BPF_PROG_TYPE_CGROUP_SKB, "bpf_get_local_storage" },
+ { BPF_PROG_TYPE_SK_REUSEPORT, "bpf_sk_select_reuseport" },
+ { BPF_PROG_TYPE_SCHED_CLS, "bpf_skb_ancestor_cgroup_id" },
+ { BPF_PROG_TYPE_SK_SKB, "bpf_sk_lookup_tcp" },
+ { BPF_PROG_TYPE_SK_SKB, "bpf_sk_lookup_udp" },
+ { BPF_PROG_TYPE_SK_SKB, "bpf_sk_release" },
+ { BPF_PROG_TYPE_XDP, "bpf_map_push_elem" },
+ { BPF_PROG_TYPE_XDP, "bpf_map_pop_elem" },
+ { BPF_PROG_TYPE_XDP, "bpf_map_peek_elem" },
+ { BPF_PROG_TYPE_SK_MSG, "bpf_msg_push_data" },
+};
+
/* Miscellaneous utility functions */
static bool check_procfs(void)
@@ -46,6 +153,11 @@ static void uppercase(char *str, size_t len)
str[i] = toupper(str[i]);
}
+static bool grep(const char *buffer, const char *pattern)
+{
+ return !!strstr(buffer, pattern);
+}
+
/* Printing utility functions */
static void
@@ -642,6 +754,36 @@ probe_map_type(enum bpf_map_type map_type, const char
*define_prefix)
define_prefix);
}
+static void
+probe_helper(__u32 id, enum bpf_prog_type prog_type, const char *name,
+ int kernel_version, bool *supported_types,
+ const char *define_prefix)
+{
+ char buf[4096], feat_name[128], define_name[128], plain_desc[128];
+ struct bpf_insn insns[2] = {
+ BPF_EMIT_CALL(id),
+ BPF_EXIT_INSN()
+ };
+ bool res = false;
+
+ if (!supported_types[prog_type])
+ goto do_print;
+
+ /* Reset buffer in case no debug info was written at previous probe */
+ *buf = '\0';
+ prog_load(prog_type, insns, ARRAY_SIZE(insns), kernel_version,
+ buf, sizeof(buf));
+ res = !grep(buf, "invalid func ") && !grep(buf, "unknown func ");
+
+do_print:
+ sprintf(feat_name, "have_%s_helper", name);
+ sprintf(define_name, "%s_helper", name);
+ uppercase(define_name, sizeof(define_name));
+ sprintf(plain_desc, "eBPF helper %s", name);
+ 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;
@@ -746,6 +888,16 @@ static int do_probe(int argc, char **argv)
for (i = BPF_MAP_TYPE_HASH; i < map_type_name_size; i++)
probe_map_type(i, define_prefix);
+ print_end_then_start_section("helpers",
+ "/*** eBPF helper functions ***/",
+ "Scanning eBPF helper functions...",
+ define_prefix);
+
+ for (i = 1; i < ARRAY_SIZE(helper_progtype_and_name); i++)
+ probe_helper(i, helper_progtype_and_name[i].progtype,
+ helper_progtype_and_name[i].name,
+ kernel_version, supported_types, define_prefix);
+
exit_close_json:
if (json_output) {
/* End current "section" of probes */
--
2.17.1
