1// SPDX-License-Identifier: GPL-2.0
2
3#include "vmlinux.h"
4#include <bpf/bpf_helpers.h>
5#include <bpf/bpf_tracing.h>
6
7char _license[] SEC("license") = "GPL";
8
9#ifndef EBUSY
10#define EBUSY 16
11#endif
12
13extern bool CONFIG_PREEMPT __kconfig __weak;
14int nr_get_errs = 0;
15int nr_del_errs = 0;
16
17struct {
18	__uint(type, BPF_MAP_TYPE_TASK_STORAGE);
19	__uint(map_flags, BPF_F_NO_PREALLOC);
20	__type(key, int);
21	__type(value, int);
22} task_storage SEC(".maps");
23
24SEC("lsm.s/socket_post_create")
25int BPF_PROG(socket_post_create, struct socket *sock, int family, int type,
26	     int protocol, int kern)
27{
28	struct task_struct *task;
29	int ret, zero = 0;
30	int *value;
31
32	if (!CONFIG_PREEMPT)
33		return 0;
34
35	task = bpf_get_current_task_btf();
36	value = bpf_task_storage_get(&task_storage, task, &zero,
37				     BPF_LOCAL_STORAGE_GET_F_CREATE);
38	if (!value)
39		__sync_fetch_and_add(&nr_get_errs, 1);
40
41	ret = bpf_task_storage_delete(&task_storage,
42				      bpf_get_current_task_btf());
43	if (ret == -EBUSY)
44		__sync_fetch_and_add(&nr_del_errs, 1);
45
46	return 0;
47}
48