tools/testing/selftests/bpf/progs/tailcall1.c

   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("classifier/" #x)                   \
  15         int bpf_func_##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("classifier")
  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 int _version SEC("version") = 1;