1// SPDX-License-Identifier: GPL-2.0
 2#include <linux/bpf.h>
 3#include <bpf/bpf_helpers.h>
 4#include "bpf_misc.h"
 5
 6int classifier_0(struct __sk_buff *skb);
 7
 8struct {
 9	__uint(type, BPF_MAP_TYPE_PROG_ARRAY);
10	__uint(max_entries, 1);
11	__uint(key_size, sizeof(__u32));
12	__array(values, void (void));
13} jmp_table0 SEC(".maps") = {
14	.values = {
15		[0] = (void *) &classifier_0,
16	},
17};
18
19struct {
20	__uint(type, BPF_MAP_TYPE_PROG_ARRAY);
21	__uint(max_entries, 1);
22	__uint(key_size, sizeof(__u32));
23	__array(values, void (void));
24} jmp_table1 SEC(".maps") = {
25	.values = {
26		[0] = (void *) &classifier_0,
27	},
28};
29
30int count = 0;
31
32static __noinline
33int subprog_tail(struct __sk_buff *skb, void *jmp_table)
34{
35	bpf_tail_call_static(skb, jmp_table, 0);
36	return 0;
37}
38
39__auxiliary
40SEC("tc")
41int classifier_0(struct __sk_buff *skb)
42{
43	count++;
44	subprog_tail(skb, &jmp_table0);
45	subprog_tail(skb, &jmp_table1);
46	return count;
47}
48
49__success
50__retval(33)
51SEC("tc")
52int tailcall_bpf2bpf_hierarchy_3(struct __sk_buff *skb)
53{
54	int ret = 0;
55
56	bpf_tail_call_static(skb, &jmp_table0, 0);
57
58	__sink(ret);
59	return ret;
60}
61
62char __license[] SEC("license") = "GPL";