1 | // SPDX-License-Identifier: GPL-2.0 |
2 | #include <linux/bpf.h> |
3 | #include <bpf/bpf_helpers.h> |
4 | |
5 | struct { |
6 | __uint(type, BPF_MAP_TYPE_ARRAY); |
7 | __uint(max_entries, 1); |
8 | __uint(key_size, sizeof(__u32)); |
9 | __uint(value_size, sizeof(__u32)); |
10 | } nop_table SEC(".maps" ); |
11 | |
12 | struct { |
13 | __uint(type, BPF_MAP_TYPE_PROG_ARRAY); |
14 | __uint(max_entries, 3); |
15 | __uint(key_size, sizeof(__u32)); |
16 | __uint(value_size, sizeof(__u32)); |
17 | } jmp_table SEC(".maps" ); |
18 | |
19 | int count = 0; |
20 | int noise = 0; |
21 | |
22 | static __always_inline int subprog_noise(void) |
23 | { |
24 | __u32 key = 0; |
25 | |
26 | bpf_map_lookup_elem(&nop_table, &key); |
27 | return 0; |
28 | } |
29 | |
30 | __noinline |
31 | int subprog_tail_2(struct __sk_buff *skb) |
32 | { |
33 | if (noise) |
34 | subprog_noise(); |
35 | bpf_tail_call_static(skb, &jmp_table, 2); |
36 | return skb->len * 3; |
37 | } |
38 | |
39 | __noinline |
40 | int subprog_tail_1(struct __sk_buff *skb) |
41 | { |
42 | bpf_tail_call_static(skb, &jmp_table, 1); |
43 | return skb->len * 2; |
44 | } |
45 | |
46 | __noinline |
47 | int subprog_tail(struct __sk_buff *skb) |
48 | { |
49 | bpf_tail_call_static(skb, &jmp_table, 0); |
50 | return skb->len; |
51 | } |
52 | |
53 | SEC("tc" ) |
54 | int classifier_1(struct __sk_buff *skb) |
55 | { |
56 | return subprog_tail_2(skb); |
57 | } |
58 | |
59 | SEC("tc" ) |
60 | int classifier_2(struct __sk_buff *skb) |
61 | { |
62 | count++; |
63 | return subprog_tail_2(skb); |
64 | } |
65 | |
66 | SEC("tc" ) |
67 | int classifier_0(struct __sk_buff *skb) |
68 | { |
69 | return subprog_tail_1(skb); |
70 | } |
71 | |
72 | SEC("tc" ) |
73 | int entry(struct __sk_buff *skb) |
74 | { |
75 | return subprog_tail(skb); |
76 | } |
77 | |
78 | char __license[] SEC("license" ) = "GPL" ; |
79 | |