1 | // SPDX-License-Identifier: GPL-2.0 |
2 | #include <linux/bpf.h> |
3 | |
4 | #include <bpf/bpf_helpers.h> |
5 | |
6 | struct { |
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 | } |
19 | TAIL_FUNC(0) |
20 | TAIL_FUNC(1) |
21 | TAIL_FUNC(2) |
22 | |
23 | SEC("tc" ) |
24 | int 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 | |
47 | char __license[] SEC("license" ) = "GPL" ; |
48 | |