1// SPDX-License-Identifier: GPL-2.0
2#include <linux/bpf.h>
3#include <bpf/bpf_helpers.h>
4#include "bpf_legacy.h"
5#include "bpf_misc.h"
6
7struct {
8	__uint(type, BPF_MAP_TYPE_PROG_ARRAY);
9	__uint(max_entries, 2);
10	__uint(key_size, sizeof(__u32));
11	__uint(value_size, sizeof(__u32));
12} jmp_table SEC(".maps");
13
14__noinline
15int subprog_tail2(struct __sk_buff *skb)
16{
17	volatile char arr[64] = {};
18
19	if (load_word(skb, 0) || load_half(skb, 0))
20		bpf_tail_call_static(skb, &jmp_table, 10);
21	else
22		bpf_tail_call_static(skb, &jmp_table, 1);
23
24	__sink(arr[sizeof(arr) - 1]);
25
26	return skb->len;
27}
28
29static __noinline
30int subprog_tail(struct __sk_buff *skb)
31{
32	volatile char arr[64] = {};
33
34	bpf_tail_call_static(skb, &jmp_table, 0);
35
36	__sink(arr[sizeof(arr) - 1]);
37
38	return skb->len * 2;
39}
40
41SEC("tc")
42int classifier_0(struct __sk_buff *skb)
43{
44	volatile char arr[128] = {};
45
46	__sink(arr[sizeof(arr) - 1]);
47
48	return subprog_tail2(skb);
49}
50
51SEC("tc")
52int classifier_1(struct __sk_buff *skb)
53{
54	volatile char arr[128] = {};
55
56	__sink(arr[sizeof(arr) - 1]);
57
58	return skb->len * 3;
59}
60
61SEC("tc")
62int entry(struct __sk_buff *skb)
63{
64	volatile char arr[128] = {};
65
66	__sink(arr[sizeof(arr) - 1]);
67
68	return subprog_tail(skb);
69}
70
71char __license[] SEC("license") = "GPL";
72