LXR linux/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
   6struct {
   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
  13static 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        }
  21TAIL_FUNC(0)
  22TAIL_FUNC(1)
  23TAIL_FUNC(2)
  24
  25SEC("classifier")
  26int 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
  39char __license[] SEC("license") = "GPL";
  40int _version SEC("version") = 1;
  41