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
7int invocations = 0, in_use = 0;
8
9struct {
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
16SEC("cgroup/sock_create")
17int 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
44SEC("cgroup/sock_release")
45int 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}
60

source code of linux/tools/testing/selftests/bpf/progs/udp_limit.c