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