tools/testing/selftests/bpf/progs/tailcall5.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 static volatile int selector;
  14
  15 #define TAIL_FUNC(x)                            \
  16         SEC("classifier/" #x)                   \
  17         int bpf_func_##x(struct __sk_buff *skb) \
  18         {                                       \
  19                 return x;                       \
  20         }
  21 TAIL_FUNC(0)
  22 TAIL_FUNC(1)
  23 TAIL_FUNC(2)
  24
  25 SEC("classifier")
  26 int entry(struct __sk_buff *skb)
  27 {
  28         int idx = 0;
  29
  30         if (selector == 1234)
  31                 idx = 1;
  32         else if (selector == 5678)
  33                 idx = 2;
  34
  35         bpf_tail_call(skb, &jmp_table, idx);
  36         return 3;
  37 }
  38
  39 char __license[] SEC("license") = "GPL";
  40 int _version SEC("version") = 1;