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         /* libbpf will adjust to valid page size */
  19         __uint(max_entries, 1000);
  20 } ringbuf1 SEC(".maps"),
  21   ringbuf2 SEC(".maps");
  22
  23 struct {
  24         __uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
  25         __uint(max_entries, 4);
  26         __type(key, int);
  27         __array(values, struct ringbuf_map);
  28 } ringbuf_arr SEC(".maps") = {
  29         .values = {
  30                 [0] = &ringbuf1,
  31                 [2] = &ringbuf2,
  32         },
  33 };
  34
  35 struct {
  36         __uint(type, BPF_MAP_TYPE_HASH_OF_MAPS);
  37         __uint(max_entries, 1);
  38         __type(key, int);
  39         __array(values, struct ringbuf_map);
  40 } ringbuf_hash SEC(".maps") = {
  41         .values = {
  42                 [0] = &ringbuf1,
  43         },
  44 };
  45
  46 /* inputs */
  47 int pid = 0;
  48 int target_ring = 0;
  49 long value = 0;
  50
  51 /* outputs */
  52 long total = 0;
  53 long dropped = 0;
  54 long skipped = 0;
  55
  56 SEC("tp/syscalls/sys_enter_getpgid")
  57 int test_ringbuf(void *ctx)
  58 {
  59         int cur_pid = bpf_get_current_pid_tgid() >> 32;
  60         struct sample *sample;
  61         void *rb;
  62
  63         if (cur_pid != pid)
  64                 return 0;
  65
  66         rb = bpf_map_lookup_elem(&ringbuf_arr, &target_ring);
  67         if (!rb) {
  68                 skipped += 1;
  69                 return 1;
  70         }
  71
  72         sample = bpf_ringbuf_reserve(rb, sizeof(*sample), 0);
  73         if (!sample) {
  74                 dropped += 1;
  75                 return 1;
  76         }
  77
  78         sample->pid = pid;
  79         bpf_get_current_comm(sample->comm, sizeof(sample->comm));
  80         sample->value = value;
  81
  82         sample->seq = total;
  83         total += 1;
  84
  85         bpf_ringbuf_submit(sample, 0);
  86
  87         return 0;
  88 }