// SPDX-License-Identifier: GPL-2.0

#include "vmlinux.h"
#include <errno.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>

char _license[] SEC("license") = "GPL";

extern bool CONFIG_PREEMPTION __kconfig __weak;
int nr_get_errs = 0;
int nr_del_errs = 0;

struct {
        __uint(type, BPF_MAP_TYPE_TASK_STORAGE);
        __uint(map_flags, BPF_F_NO_PREALLOC);
        __type(key, int);
        __type(value, int);
} task_storage SEC(".maps");

SEC("lsm.s/socket_post_create")
int BPF_PROG(socket_post_create, struct socket *sock, int family, int type,
             int protocol, int kern)
{
        struct task_struct *task;
        int ret, zero = 0;
        int *value;

        if (!CONFIG_PREEMPTION)
                return 0;

        task = bpf_get_current_task_btf();
        value = bpf_task_storage_get(&task_storage, task, &zero,
                                     BPF_LOCAL_STORAGE_GET_F_CREATE);
        if (!value)
                __sync_fetch_and_add(&nr_get_errs, 1);

        ret = bpf_task_storage_delete(&task_storage,
                                      bpf_get_current_task_btf());
        if (ret == -EDEADLK || ret == -ETIMEDOUT)
                __sync_fetch_and_add(&nr_del_errs, 1);

        return 0;
}