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// SPDX-License-Identifier: GPL-2.0-only
#include <sys/socket.h>
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
int invocations = 0, in_use = 0;
struct {
__uint(type, BPF_MAP_TYPE_SK_STORAGE);
__uint(map_flags, BPF_F_NO_PREALLOC);
__type(key, int);
__type(value, int);
} sk_map SEC(".maps");
SEC("cgroup/sock_create")
int sock(struct bpf_sock *ctx)
{
int *sk_storage;
__u32 key;
if (ctx->type != SOCK_DGRAM)
return 1;
sk_storage = bpf_sk_storage_get(&sk_map, ctx, 0,
BPF_SK_STORAGE_GET_F_CREATE);
if (!sk_storage)
return 0;
*sk_storage = 0xdeadbeef;
__sync_fetch_and_add(&invocations, 1);
if (in_use > 0) {
/* BPF_CGROUP_INET_SOCK_RELEASE is _not_ called
* when we return an error from the BPF
* program!
*/
return 0;
}
__sync_fetch_and_add(&in_use, 1);
return 1;
}
SEC("cgroup/sock_release")
int sock_release(struct bpf_sock *ctx)
{
int *sk_storage;
__u32 key;
if (ctx->type != SOCK_DGRAM)
return 1;
sk_storage = bpf_sk_storage_get(&sk_map, ctx, 0, 0);
if (!sk_storage || *sk_storage != 0xdeadbeef)
return 0;
__sync_fetch_and_add(&invocations, 1);
__sync_fetch_and_add(&in_use, -1);
return 1;
}
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