aboutsummaryrefslogtreecommitdiff
path: root/net/netfilter/nf_sockopt.c
blob: 0e5c5e2047995bf03c422ef68f4233b38154220d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/netfilter.h>
#include <linux/mutex.h>
#include <net/sock.h>

#include "nf_internals.h"

/* Sockopts only registered and called from user context, so
   net locking would be overkill.  Also, [gs]etsockopt calls may
   sleep. */
static DEFINE_MUTEX(nf_sockopt_mutex);
static LIST_HEAD(nf_sockopts);

/* Do exclusive ranges overlap? */
static inline int overlap(int min1, int max1, int min2, int max2)
{
	return max1 > min2 && min1 < max2;
}

/* Functions to register sockopt ranges (exclusive). */
int nf_register_sockopt(struct nf_sockopt_ops *reg)
{
	struct list_head *i;
	int ret = 0;

	if (mutex_lock_interruptible(&nf_sockopt_mutex) != 0)
		return -EINTR;

	list_for_each(i, &nf_sockopts) {
		struct nf_sockopt_ops *ops = (struct nf_sockopt_ops *)i;
		if (ops->pf == reg->pf
		    && (overlap(ops->set_optmin, ops->set_optmax, 
				reg->set_optmin, reg->set_optmax)
			|| overlap(ops->get_optmin, ops->get_optmax, 
				   reg->get_optmin, reg->get_optmax))) {
			NFDEBUG("nf_sock overlap: %u-%u/%u-%u v %u-%u/%u-%u\n",
				ops->set_optmin, ops->set_optmax, 
				ops->get_optmin, ops->get_optmax, 
				reg->set_optmin, reg->set_optmax,
				reg->get_optmin, reg->get_optmax);
			ret = -EBUSY;
			goto out;
		}
	}

	list_add(&reg->list, &nf_sockopts);
out:
	mutex_unlock(&nf_sockopt_mutex);
	return ret;
}
EXPORT_SYMBOL(nf_register_sockopt);

void nf_unregister_sockopt(struct nf_sockopt_ops *reg)
{
	/* No point being interruptible: we're probably in cleanup_module() */
 restart:
	mutex_lock(&nf_sockopt_mutex);
	if (reg->use != 0) {
		/* To be woken by nf_sockopt call... */
		/* FIXME: Stuart Young's name appears gratuitously. */
		set_current_state(TASK_UNINTERRUPTIBLE);
		reg->cleanup_task = current;
		mutex_unlock(&nf_sockopt_mutex);
		schedule();
		goto restart;
	}
	list_del(&reg->list);
	mutex_unlock(&nf_sockopt_mutex);
}
EXPORT_SYMBOL(nf_unregister_sockopt);

/* Call get/setsockopt() */
static int nf_sockopt(struct sock *sk, int pf, int val, 
		      char __user *opt, int *len, int get)
{
	struct list_head *i;
	struct nf_sockopt_ops *ops;
	int ret;

	if (mutex_lock_interruptible(&nf_sockopt_mutex) != 0)
		return -EINTR;

	list_for_each(i, &nf_sockopts) {
		ops = (struct nf_sockopt_ops *)i;
		if (ops->pf == pf) {
			if (get) {
				if (val >= ops->get_optmin
				    && val < ops->get_optmax) {
					ops->use++;
					mutex_unlock(&nf_sockopt_mutex);
					ret = ops->get(sk, val, opt, len);
					goto out;
				}
			} else {
				if (val >= ops->set_optmin
				    && val < ops->set_optmax) {
					ops->use++;
					mutex_unlock(&nf_sockopt_mutex);
					ret = ops->set(sk, val, opt, *len);
					goto out;
				}
			}
		}
	}
	mutex_unlock(&nf_sockopt_mutex);
	return -ENOPROTOOPT;
	
 out:
	mutex_lock(&nf_sockopt_mutex);
	ops->use--;
	if (ops->cleanup_task)
		wake_up_process(ops->cleanup_task);
	mutex_unlock(&nf_sockopt_mutex);
	return ret;
}

int nf_setsockopt(struct sock *sk, int pf, int val, char __user *opt,
		  int len)
{
	return nf_sockopt(sk, pf, val, opt, &len, 0);
}
EXPORT_SYMBOL(nf_setsockopt);

int nf_getsockopt(struct sock *sk, int pf, int val, char __user *opt, int *len)
{
	return nf_sockopt(sk, pf, val, opt, len, 1);
}
EXPORT_SYMBOL(nf_getsockopt);