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1// SPDX-License-Identifier: GPL-2.0-only2 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_ called34 * when we return an error from the BPF35 * 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