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, 1);
   9        __uint(key_size, sizeof(__u32));
  10        __uint(value_size, sizeof(__u32));
  11} jmp_table SEC(".maps");
  12
  13static __noinline
  14int 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
  23int count = 0;
  24
  25SEC("classifier/0")
  26int bpf_func_0(struct __sk_buff *skb)
  27{
  28        count++;
  29        return subprog_tail(skb);
  30}
  31
  32SEC("classifier")
  33int entry(struct __sk_buff *skb)
  34{
  35        bpf_tail_call_static(skb, &jmp_table, 0);
  36
  37        return 0;
  38}
  39
  40char __license[] SEC("license") = "GPL";
  41int _version SEC("version") = 1;
  42