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 }
60
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