1// SPDX-License-Identifier: GPL-2.0
 2#include <linux/bpf.h>
 3
 4#include <bpf/bpf_helpers.h>
 5
 6struct {
 7	__uint(type, BPF_MAP_TYPE_PROG_ARRAY);
 8	__uint(max_entries, 3);
 9	__uint(key_size, sizeof(__u32));
10	__uint(value_size, sizeof(__u32));
11} jmp_table SEC(".maps");
12
13#define TAIL_FUNC(x) 				\
14	SEC("tc")				\
15	int classifier_##x(struct __sk_buff *skb)	\
16	{					\
17		return x;			\
18	}
19TAIL_FUNC(0)
20TAIL_FUNC(1)
21TAIL_FUNC(2)
22
23SEC("tc")
24int entry(struct __sk_buff *skb)
25{
26	/* Multiple locations to make sure we patch
27	 * all of them.
28	 */
29	bpf_tail_call_static(skb, &jmp_table, 0);
30	bpf_tail_call_static(skb, &jmp_table, 0);
31	bpf_tail_call_static(skb, &jmp_table, 0);
32	bpf_tail_call_static(skb, &jmp_table, 0);
33
34	bpf_tail_call_static(skb, &jmp_table, 1);
35	bpf_tail_call_static(skb, &jmp_table, 1);
36	bpf_tail_call_static(skb, &jmp_table, 1);
37	bpf_tail_call_static(skb, &jmp_table, 1);
38
39	bpf_tail_call_static(skb, &jmp_table, 2);
40	bpf_tail_call_static(skb, &jmp_table, 2);
41	bpf_tail_call_static(skb, &jmp_table, 2);
42	bpf_tail_call_static(skb, &jmp_table, 2);
43
44	return 3;
45}
46
47char __license[] SEC("license") = "GPL";