1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/bpf.h>
3
4 #include <bpf/bpf_helpers.h>
5
6 struct {
7 __uint(type, BPF_MAP_TYPE_PROG_ARRAY);
8 __uint(max_entries, 5);
9 __uint(key_size, sizeof(__u32));
10 __uint(value_size, sizeof(__u32));
11 } jmp_table SEC(".maps");
12
13 SEC("tc")
classifier_0(struct __sk_buff * skb)14 int classifier_0(struct __sk_buff *skb)
15 {
16 bpf_tail_call_static(skb, &jmp_table, 1);
17 return 0;
18 }
19
20 SEC("tc")
classifier_1(struct __sk_buff * skb)21 int classifier_1(struct __sk_buff *skb)
22 {
23 bpf_tail_call_static(skb, &jmp_table, 2);
24 return 1;
25 }
26
27 SEC("tc")
classifier_2(struct __sk_buff * skb)28 int classifier_2(struct __sk_buff *skb)
29 {
30 return 2;
31 }
32
33 SEC("tc")
classifier_3(struct __sk_buff * skb)34 int classifier_3(struct __sk_buff *skb)
35 {
36 bpf_tail_call_static(skb, &jmp_table, 4);
37 return 3;
38 }
39
40 SEC("tc")
classifier_4(struct __sk_buff * skb)41 int classifier_4(struct __sk_buff *skb)
42 {
43 bpf_tail_call_static(skb, &jmp_table, 3);
44 return 4;
45 }
46
47 SEC("tc")
entry(struct __sk_buff * skb)48 int entry(struct __sk_buff *skb)
49 {
50 bpf_tail_call_static(skb, &jmp_table, 0);
51 /* Check multi-prog update. */
52 bpf_tail_call_static(skb, &jmp_table, 2);
53 /* Check tail call limit. */
54 bpf_tail_call_static(skb, &jmp_table, 3);
55 return 3;
56 }
57
58 char __license[] SEC("license") = "GPL";
59