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 #define __unused __attribute__((unused))
7 
8 struct {
9 	__uint(type, BPF_MAP_TYPE_PROG_ARRAY);
10 	__uint(max_entries, 1);
11 	__uint(key_size, sizeof(__u32));
12 	__uint(value_size, sizeof(__u32));
13 } jmp_table SEC(".maps");
14 
15 int done = 0;
16 
17 SEC("tc")
18 int classifier_0(struct __sk_buff *skb __unused)
19 {
20 	done = 1;
21 	return 0;
22 }
23 
24 static __noinline
25 int subprog_tail(struct __sk_buff *skb)
26 {
27 	/* Don't propagate the constant to the caller */
28 	volatile int ret = 1;
29 
30 	bpf_tail_call_static(skb, &jmp_table, 0);
31 	return ret;
32 }
33 
34 SEC("tc")
35 int entry(struct __sk_buff *skb)
36 {
37 	/* Have data on stack which size is not a multiple of 8 */
38 	volatile char arr[1] = {};
39 
40 	__sink(arr[0]);
41 
42 	return subprog_tail(skb);
43 }
44 
45 char __license[] SEC("license") = "GPL";
46