tools/testing/selftests/bpf/progs/tailcall_bpf2bpf2.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/bpf.h>
   3 #include <bpf/bpf_helpers.h>
   4 #include "bpf_legacy.h"
   5
   6 struct {
   7         __uint(type, BPF_MAP_TYPE_PROG_ARRAY);
   8         __uint(max_entries, 1);
   9         __uint(key_size, sizeof(__u32));
  10         __uint(value_size, sizeof(__u32));
  11 } jmp_table SEC(".maps");
  12
  13 static __noinline
  14 int subprog_tail(struct __sk_buff *skb)
  15 {
  16         if (load_byte(skb, 0))
  17                 bpf_tail_call_static(skb, &jmp_table, 1);
  18         else
  19                 bpf_tail_call_static(skb, &jmp_table, 0);
  20         return 1;
  21 }
  22
  23 static volatile int count;
  24
  25 SEC("classifier/0")
  26 int bpf_func_0(struct __sk_buff *skb)
  27 {
  28         count++;
  29         return subprog_tail(skb);
  30 }
  31
  32 SEC("classifier")
  33 int entry(struct __sk_buff *skb)
  34 {
  35         bpf_tail_call_static(skb, &jmp_table, 0);
  36
  37         return 0;
  38 }
  39
  40 char __license[] SEC("license") = "GPL";
  41 int _version SEC("version") = 1;