LXR linux/tools/testing/selftests/bpf/progs/tailcall

   1// SPDX-License-Identifier: GPL-2.0
   2#include <linux/bpf.h>
   3#include <bpf/bpf_helpers.h>
   4#include "bpf_legacy.h"
   5
   6struct {
   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
  14int 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
  26static __noinline
  27int 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
  36SEC("classifier/0")
  37int bpf_func_0(struct __sk_buff *skb)
  38{
  39        volatile char arr[128] = {};
  40
  41        return subprog_tail2(skb);
  42}
  43
  44SEC("classifier/1")
  45int bpf_func_1(struct __sk_buff *skb)
  46{
  47        volatile char arr[128] = {};
  48
  49        return skb->len * 3;
  50}
  51
  52SEC("classifier")
  53int entry(struct __sk_buff *skb)
  54{
  55        volatile char arr[128] = {};
  56
  57        return subprog_tail(skb);
  58}
  59
  60char __license[] SEC("license") = "GPL";
  61int _version SEC("version") = 1;
  62