1// SPDX-License-Identifier: GPL-2.0
 2#include <linux/init.h>
 3#include <linux/module.h>
 4#include <linux/uaccess.h>
 5#include <linux/bpfilter.h>
 6#include <uapi/linux/bpf.h>
 7#include <linux/wait.h>
 8#include <linux/kmod.h>
 9#include <linux/fs.h>
10#include <linux/file.h>
11
12struct bpfilter_umh_ops bpfilter_ops;
13EXPORT_SYMBOL_GPL(bpfilter_ops);
14
15void bpfilter_umh_cleanup(struct umd_info *info)
16{
17	fput(info->pipe_to_umh);
18	fput(info->pipe_from_umh);
19	put_pid(info->tgid);
20	info->tgid = NULL;
21}
22EXPORT_SYMBOL_GPL(bpfilter_umh_cleanup);
23
24static int bpfilter_mbox_request(struct sock *sk, int optname, sockptr_t optval,
25				 unsigned int optlen, bool is_set)
26{
27	int err;
28	mutex_lock(&bpfilter_ops.lock);
29	if (!bpfilter_ops.sockopt) {
30		mutex_unlock(&bpfilter_ops.lock);
31		request_module("bpfilter");
32		mutex_lock(&bpfilter_ops.lock);
33
34		if (!bpfilter_ops.sockopt) {
35			err = -ENOPROTOOPT;
36			goto out;
37		}
38	}
39	if (bpfilter_ops.info.tgid &&
40	    thread_group_exited(bpfilter_ops.info.tgid))
41		bpfilter_umh_cleanup(&bpfilter_ops.info);
42
43	if (!bpfilter_ops.info.tgid) {
44		err = bpfilter_ops.start();
45		if (err)
46			goto out;
47	}
48	err = bpfilter_ops.sockopt(sk, optname, optval, optlen, is_set);
49out:
50	mutex_unlock(&bpfilter_ops.lock);
51	return err;
52}
53
54int bpfilter_ip_set_sockopt(struct sock *sk, int optname, sockptr_t optval,
55			    unsigned int optlen)
56{
57	return bpfilter_mbox_request(sk, optname, optval, optlen, true);
58}
59
60int bpfilter_ip_get_sockopt(struct sock *sk, int optname, char __user *optval,
61			    int __user *optlen)
62{
63	int len;
64
65	if (get_user(len, optlen))
66		return -EFAULT;
67
68	return bpfilter_mbox_request(sk, optname, USER_SOCKPTR(optval), len,
69				     false);
70}
71
72static int __init bpfilter_sockopt_init(void)
73{
74	mutex_init(&bpfilter_ops.lock);
75	bpfilter_ops.info.tgid = NULL;
76	bpfilter_ops.info.driver_name = "bpfilter_umh";
77
78	return 0;
79}
80device_initcall(bpfilter_sockopt_init);