1// SPDX-License-Identifier: GPL-2.0
 2#include <linux/bpf.h>
 3#include <bpf/bpf_helpers.h>
 4
 5struct {
 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	}
18TAIL_FUNC(0)
19TAIL_FUNC(1)
20
21static __noinline
22int subprog_tail(struct __sk_buff *skb)
23{
24	bpf_tail_call_static(skb, &jmp_table, 0);
25
26	return skb->len * 2;
27}
28
29SEC("tc")
30int entry(struct __sk_buff *skb)
31{
32	bpf_tail_call_static(skb, &jmp_table, 1);
33
34	return subprog_tail(skb);
35}
36
37char __license[] SEC("license") = "GPL";

 1// SPDX-License-Identifier: GPL-2.0
 2#include <linux/bpf.h>
 3#include <bpf/bpf_helpers.h>
 4
 5struct {
 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	}
18TAIL_FUNC(0)
19TAIL_FUNC(1)
20
21static __noinline
22int subprog_tail(struct __sk_buff *skb)
23{
24	bpf_tail_call_static(skb, &jmp_table, 0);
25
26	return skb->len * 2;
27}
28
29SEC("tc")
30int entry(struct __sk_buff *skb)
31{
32	bpf_tail_call_static(skb, &jmp_table, 1);
33
34	return subprog_tail(skb);
35}
36
37char __license[] SEC("license") = "GPL";