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         __u32 key;
  21
  22         if (ctx->type != SOCK_DGRAM)
  23                 return 1;
  24
  25         sk_storage = bpf_sk_storage_get(&sk_map, ctx, 0,
  26                                         BPF_SK_STORAGE_GET_F_CREATE);
  27         if (!sk_storage)
  28                 return 0;
  29         *sk_storage = 0xdeadbeef;
  30
  31         __sync_fetch_and_add(&invocations, 1);
  32
  33         if (in_use > 0) {
  34                 /* BPF_CGROUP_INET_SOCK_RELEASE is _not_ called
  35                  * when we return an error from the BPF
  36                  * program!
  37                  */
  38                 return 0;
  39         }
  40
  41         __sync_fetch_and_add(&in_use, 1);
  42         return 1;
  43 }
  44
  45 SEC("cgroup/sock_release")
  46 int sock_release(struct bpf_sock *ctx)
  47 {
  48         int *sk_storage;
  49         __u32 key;
  50
  51         if (ctx->type != SOCK_DGRAM)
  52                 return 1;
  53
  54         sk_storage = bpf_sk_storage_get(&sk_map, ctx, 0, 0);
  55         if (!sk_storage || *sk_storage != 0xdeadbeef)
  56                 return 0;
  57
  58         __sync_fetch_and_add(&invocations, 1);
  59         __sync_fetch_and_add(&in_use, -1);
  60         return 1;
  61 }