1// SPDX-License-Identifier: GPL-2.0
2#include <linux/bpf.h>
3#include <bpf/bpf_helpers.h>
4
5struct {
6	__uint(type, BPF_MAP_TYPE_PROG_ARRAY);
7	__uint(max_entries, 3);
8	__uint(key_size, sizeof(__u32));
9	__uint(value_size, sizeof(__u32));
10} jmp_table SEC(".maps");
11
12static volatile int count;
13
14__noinline
15int subprog_tail_2(struct __sk_buff *skb)
16{
17	bpf_tail_call_static(skb, &jmp_table, 2);
18	return skb->len * 3;
19}
20
21__noinline
22int subprog_tail_1(struct __sk_buff *skb)
23{
24	bpf_tail_call_static(skb, &jmp_table, 1);
25	return skb->len * 2;
26}
27
28__noinline
29int subprog_tail(struct __sk_buff *skb)
30{
31	bpf_tail_call_static(skb, &jmp_table, 0);
32	return skb->len;
33}
34
35SEC("classifier/1")
36int bpf_func_1(struct __sk_buff *skb)
37{
38	return subprog_tail_2(skb);
39}
40
41SEC("classifier/2")
42int bpf_func_2(struct __sk_buff *skb)
43{
44	count++;
45	return subprog_tail_2(skb);
46}
47
48SEC("classifier/0")
49int bpf_func_0(struct __sk_buff *skb)
50{
51	return subprog_tail_1(skb);
52}
53
54SEC("classifier")
55int entry(struct __sk_buff *skb)
56{
57	return subprog_tail(skb);
58}
59
60char __license[] SEC("license") = "GPL";
61int _version SEC("version") = 1;
62