tools/testing/selftests/bpf/progs/tailcall_bpf2bpf3.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, 2);
   9         __uint(key_size, sizeof(__u32));
  10         __uint(value_size, sizeof(__u32));
  11 } jmp_table SEC(".maps");
  12
  13 __noinline
  14 int subprog_tail2(struct __sk_buff *skb)
  15 {
  16         volatile char arr[64] = {};
  17
  18         if (load_word(skb, 0) || load_half(skb, 0))
  19                 bpf_tail_call_static(skb, &jmp_table, 10);
  20         else
  21                 bpf_tail_call_static(skb, &jmp_table, 1);
  22
  23         return skb->len;
  24 }
  25
  26 static __noinline
  27 int subprog_tail(struct __sk_buff *skb)
  28 {
  29         volatile char arr[64] = {};
  30
  31         bpf_tail_call_static(skb, &jmp_table, 0);
  32
  33         return skb->len * 2;
  34 }
  35
  36 SEC("classifier/0")
  37 int bpf_func_0(struct __sk_buff *skb)
  38 {
  39         volatile char arr[128] = {};
  40
  41         return subprog_tail2(skb);
  42 }
  43
  44 SEC("classifier/1")
  45 int bpf_func_1(struct __sk_buff *skb)
  46 {
  47         volatile char arr[128] = {};
  48
  49         return skb->len * 3;
  50 }
  51
  52 SEC("classifier")
  53 int entry(struct __sk_buff *skb)
  54 {
  55         volatile char arr[128] = {};
  56
  57         return subprog_tail(skb);
  58 }
  59
  60 char __license[] SEC("license") = "GPL";
  61 int _version SEC("version") = 1;