1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright Leon Hwang */
3
4 #include "vmlinux.h"
5 #include <bpf/bpf_helpers.h>
6 #include <bpf/bpf_tracing.h>
7
8 struct {
9 __uint(type, BPF_MAP_TYPE_PROG_ARRAY);
10 __uint(max_entries, 1);
11 __uint(key_size, sizeof(__u32));
12 __uint(value_size, sizeof(__u32));
13 } jmp_table SEC(".maps");
14
15 int count = 0;
16
17 static __noinline
18 int subprog_tail(void *ctx)
19 {
20 bpf_tail_call_static(ctx, &jmp_table, 0);
21 return 0;
22 }
23
24 SEC("fentry/dummy")
25 int BPF_PROG(fentry, struct sk_buff *skb)
26 {
27 count++;
28 subprog_tail(ctx);
29 subprog_tail(ctx);
30
31 return 0;
32 }
33
34
35 char _license[] SEC("license") = "GPL";
36
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.