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 | |