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

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Copyright (c) 2020 Facebook
   3
   4 #include <linux/bpf.h>
   5 #include <bpf/bpf_helpers.h>
   6
   7 char _license[] SEC("license") = "GPL";
   8
   9 struct sample {
  10         int pid;
  11         int seq;
  12         long value;
  13         char comm[16];
  14 };
  15
  16 struct ringbuf_map {
  17         __uint(type, BPF_MAP_TYPE_RINGBUF);
  18         __uint(max_entries, 1 << 12);
  19 } ringbuf1 SEC(".maps"),
  20   ringbuf2 SEC(".maps");
  21
  22 struct {
  23         __uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
  24         __uint(max_entries, 4);
  25         __type(key, int);
  26         __array(values, struct ringbuf_map);
  27 } ringbuf_arr SEC(".maps") = {
  28         .values = {
  29                 [0] = &ringbuf1,
  30                 [2] = &ringbuf2,
  31         },
  32 };
  33
  34 /* inputs */
  35 int pid = 0;
  36 int target_ring = 0;
  37 long value = 0;
  38
  39 /* outputs */
  40 long total = 0;
  41 long dropped = 0;
  42 long skipped = 0;
  43
  44 SEC("tp/syscalls/sys_enter_getpgid")
  45 int test_ringbuf(void *ctx)
  46 {
  47         int cur_pid = bpf_get_current_pid_tgid() >> 32;
  48         struct sample *sample;
  49         void *rb;
  50         int zero = 0;
  51
  52         if (cur_pid != pid)
  53                 return 0;
  54
  55         rb = bpf_map_lookup_elem(&ringbuf_arr, &target_ring);
  56         if (!rb) {
  57                 skipped += 1;
  58                 return 1;
  59         }
  60
  61         sample = bpf_ringbuf_reserve(rb, sizeof(*sample), 0);
  62         if (!sample) {
  63                 dropped += 1;
  64                 return 1;
  65         }
  66
  67         sample->pid = pid;
  68         bpf_get_current_comm(sample->comm, sizeof(sample->comm));
  69         sample->value = value;
  70
  71         sample->seq = total;
  72         total += 1;
  73
  74         bpf_ringbuf_submit(sample, 0);
  75
  76         return 0;
  77 }