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_PROG_ARRAY); |
7 | __uint(max_entries, 2); |
8 | __uint(key_size, sizeof(__u32)); |
9 | __uint(value_size, sizeof(__u32)); |
10 | } jmp_table SEC(".maps" ); |
11 | |
12 | #define TAIL_FUNC(x) \ |
13 | SEC("tc") \ |
14 | int classifier_##x(struct __sk_buff *skb) \ |
15 | { \ |
16 | return x; \ |
17 | } |
18 | TAIL_FUNC(0) |
19 | TAIL_FUNC(1) |
20 | |
21 | static __noinline |
22 | int subprog_tail(struct __sk_buff *skb) |
23 | { |
24 | bpf_tail_call_static(skb, &jmp_table, 0); |
25 | |
26 | return skb->len * 2; |
27 | } |
28 | |
29 | SEC("tc" ) |
30 | int entry(struct __sk_buff *skb) |
31 | { |
32 | bpf_tail_call_static(skb, &jmp_table, 1); |
33 | |
34 | return subprog_tail(skb); |
35 | } |
36 | |
37 | char __license[] SEC("license" ) = "GPL" ; |
38 | |