tailcall_bpf2bpf_hierarchy2.c

 1// SPDX-License-Identifier: GPL-2.0
 2#include <linux/bpf.h>
 3#include <bpf/bpf_helpers.h>
 4#include "bpf_misc.h"
 5#include "bpf_test_utils.h"
 6
 7int classifier_0(struct __sk_buff *skb);
 8int classifier_1(struct __sk_buff *skb);
 9
10struct {
11	__uint(type, BPF_MAP_TYPE_PROG_ARRAY);
12	__uint(max_entries, 2);
13	__uint(key_size, sizeof(__u32));
14	__array(values, void (void));
15} jmp_table SEC(".maps") = {
16	.values = {
17		[0] = (void *) &classifier_0,
18		[1] = (void *) &classifier_1,
19	},
20};
21
22int count0 = 0;
23int count1 = 0;
24
25static __noinline
26int subprog_tail0(struct __sk_buff *skb)
27{
28	bpf_tail_call_static(skb, &jmp_table, 0);
29	return 0;
30}
31
32__auxiliary
33SEC("tc")
34int classifier_0(struct __sk_buff *skb)
35{
36	count0++;
37	subprog_tail0(skb);
38	return 0;
39}
40
41static __noinline
42int subprog_tail1(struct __sk_buff *skb)
43{
44	bpf_tail_call_static(skb, &jmp_table, 1);
45	return 0;
46}
47
48__auxiliary
49SEC("tc")
50int classifier_1(struct __sk_buff *skb)
51{
52	count1++;
53	subprog_tail1(skb);
54	return 0;
55}
56
57__success
58__retval(33)
59SEC("tc")
60int tailcall_bpf2bpf_hierarchy_2(struct __sk_buff *skb)
61{
62	int ret = 0;
63
64	clobber_regs_stack();
65
66	subprog_tail0(skb);
67	subprog_tail1(skb);
68
69	__sink(ret);
70	return (count1 << 16) | count0;
71}
72
73char __license[] SEC("license") = "GPL";