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

   1 // SPDX-License-Identifier: GPL-2.0-only
   2
   3 #include <sys/socket.h>
   4 #include <linux/bpf.h>
   5 #include <bpf/bpf_helpers.h>
   6
   7 int invocations = 0, in_use = 0;
   8
   9 struct {
  10         __uint(type, BPF_MAP_TYPE_SK_STORAGE);
  11         __uint(map_flags, BPF_F_NO_PREALLOC);
  12         __type(key, int);
  13         __type(value, int);
  14 } sk_map SEC(".maps");
  15
  16 SEC("cgroup/sock_create")
  17 int sock(struct bpf_sock *ctx)
  18 {
  19         int *sk_storage;
  20
  21         if (ctx->type != SOCK_DGRAM)
  22                 return 1;
  23
  24         sk_storage = bpf_sk_storage_get(&sk_map, ctx, 0,
  25                                         BPF_SK_STORAGE_GET_F_CREATE);
  26         if (!sk_storage)
  27                 return 0;
  28         *sk_storage = 0xdeadbeef;
  29
  30         __sync_fetch_and_add(&invocations, 1);
  31
  32         if (in_use > 0) {
  33                 /* BPF_CGROUP_INET_SOCK_RELEASE is _not_ called
  34                  * when we return an error from the BPF
  35                  * program!
  36                  */
  37                 return 0;
  38         }
  39
  40         __sync_fetch_and_add(&in_use, 1);
  41         return 1;
  42 }
  43
  44 SEC("cgroup/sock_release")
  45 int sock_release(struct bpf_sock *ctx)
  46 {
  47         int *sk_storage;
  48
  49         if (ctx->type != SOCK_DGRAM)
  50                 return 1;
  51
  52         sk_storage = bpf_sk_storage_get(&sk_map, ctx, 0, 0);
  53         if (!sk_storage || *sk_storage != 0xdeadbeef)
  54                 return 0;
  55
  56         __sync_fetch_and_add(&invocations, 1);
  57         __sync_fetch_and_add(&in_use, -1);
  58         return 1;
  59 }