tools/testing/selftests/bpf/progs/tailcall_bpf2bpf4.c

   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, 3);
   8         __uint(key_size, sizeof(__u32));
   9         __uint(value_size, sizeof(__u32));
  10 } jmp_table SEC(".maps");
  11
  12 static volatile int count;
  13
  14 __noinline
  15 int subprog_tail_2(struct __sk_buff *skb)
  16 {
  17         bpf_tail_call_static(skb, &jmp_table, 2);
  18         return skb->len * 3;
  19 }
  20
  21 __noinline
  22 int subprog_tail_1(struct __sk_buff *skb)
  23 {
  24         bpf_tail_call_static(skb, &jmp_table, 1);
  25         return skb->len * 2;
  26 }
  27
  28 __noinline
  29 int subprog_tail(struct __sk_buff *skb)
  30 {
  31         bpf_tail_call_static(skb, &jmp_table, 0);
  32         return skb->len;
  33 }
  34
  35 SEC("classifier/1")
  36 int bpf_func_1(struct __sk_buff *skb)
  37 {
  38         return subprog_tail_2(skb);
  39 }
  40
  41 SEC("classifier/2")
  42 int bpf_func_2(struct __sk_buff *skb)
  43 {
  44         count++;
  45         return subprog_tail_2(skb);
  46 }
  47
  48 SEC("classifier/0")
  49 int bpf_func_0(struct __sk_buff *skb)
  50 {
  51         return subprog_tail_1(skb);
  52 }
  53
  54 SEC("classifier")
  55 int entry(struct __sk_buff *skb)
  56 {
  57         return subprog_tail(skb);
  58 }
  59
  60 char __license[] SEC("license") = "GPL";
  61 int _version SEC("version") = 1;