1#include <linux/kernel.h>
2#include <linux/init.h>
3#include <linux/module.h>
4#include <linux/skbuff.h>
5#include <linux/netfilter.h>
6#include <linux/mutex.h>
7#include <net/sock.h>
8
9#include "nf_internals.h"
10
11/* Sockopts only registered and called from user context, so
12   net locking would be overkill.  Also, [gs]etsockopt calls may
13   sleep. */
14static DEFINE_MUTEX(nf_sockopt_mutex);
15static LIST_HEAD(nf_sockopts);
16
17/* Do exclusive ranges overlap? */
18static inline int overlap(int min1, int max1, int min2, int max2)
19{
20	return max1 > min2 && min1 < max2;
21}
22
23/* Functions to register sockopt ranges (exclusive). */
24int nf_register_sockopt(struct nf_sockopt_ops *reg)
25{
26	struct nf_sockopt_ops *ops;
27	int ret = 0;
28
29	mutex_lock(&nf_sockopt_mutex);
30	list_for_each_entry(ops, &nf_sockopts, list) {
31		if (ops->pf == reg->pf
32		    && (overlap(ops->set_optmin, ops->set_optmax,
33				reg->set_optmin, reg->set_optmax)
34			|| overlap(ops->get_optmin, ops->get_optmax,
35				   reg->get_optmin, reg->get_optmax))) {
36			NFDEBUG("nf_sock overlap: %u-%u/%u-%u v %u-%u/%u-%u\n",
37				ops->set_optmin, ops->set_optmax,
38				ops->get_optmin, ops->get_optmax,
39				reg->set_optmin, reg->set_optmax,
40				reg->get_optmin, reg->get_optmax);
41			ret = -EBUSY;
42			goto out;
43		}
44	}
45
46	list_add(&reg->list, &nf_sockopts);
47out:
48	mutex_unlock(&nf_sockopt_mutex);
49	return ret;
50}
51EXPORT_SYMBOL(nf_register_sockopt);
52
53void nf_unregister_sockopt(struct nf_sockopt_ops *reg)
54{
55	mutex_lock(&nf_sockopt_mutex);
56	list_del(&reg->list);
57	mutex_unlock(&nf_sockopt_mutex);
58}
59EXPORT_SYMBOL(nf_unregister_sockopt);
60
61static struct nf_sockopt_ops *nf_sockopt_find(struct sock *sk, u_int8_t pf,
62		int val, int get)
63{
64	struct nf_sockopt_ops *ops;
65
66	mutex_lock(&nf_sockopt_mutex);
67	list_for_each_entry(ops, &nf_sockopts, list) {
68		if (ops->pf == pf) {
69			if (!try_module_get(ops->owner))
70				goto out_nosup;
71
72			if (get) {
73				if (val >= ops->get_optmin &&
74						val < ops->get_optmax)
75					goto out;
76			} else {
77				if (val >= ops->set_optmin &&
78						val < ops->set_optmax)
79					goto out;
80			}
81			module_put(ops->owner);
82		}
83	}
84out_nosup:
85	ops = ERR_PTR(-ENOPROTOOPT);
86out:
87	mutex_unlock(&nf_sockopt_mutex);
88	return ops;
89}
90
91/* Call get/setsockopt() */
92static int nf_sockopt(struct sock *sk, u_int8_t pf, int val,
93		      char __user *opt, int *len, int get)
94{
95	struct nf_sockopt_ops *ops;
96	int ret;
97
98	ops = nf_sockopt_find(sk, pf, val, get);
99	if (IS_ERR(ops))
100		return PTR_ERR(ops);
101
102	if (get)
103		ret = ops->get(sk, val, opt, len);
104	else
105		ret = ops->set(sk, val, opt, *len);
106
107	module_put(ops->owner);
108	return ret;
109}
110
111int nf_setsockopt(struct sock *sk, u_int8_t pf, int val, char __user *opt,
112		  unsigned int len)
113{
114	return nf_sockopt(sk, pf, val, opt, &len, 0);
115}
116EXPORT_SYMBOL(nf_setsockopt);
117
118int nf_getsockopt(struct sock *sk, u_int8_t pf, int val, char __user *opt,
119		  int *len)
120{
121	return nf_sockopt(sk, pf, val, opt, len, 1);
122}
123EXPORT_SYMBOL(nf_getsockopt);
124
125#ifdef CONFIG_COMPAT
126static int compat_nf_sockopt(struct sock *sk, u_int8_t pf, int val,
127			     char __user *opt, int *len, int get)
128{
129	struct nf_sockopt_ops *ops;
130	int ret;
131
132	ops = nf_sockopt_find(sk, pf, val, get);
133	if (IS_ERR(ops))
134		return PTR_ERR(ops);
135
136	if (get) {
137		if (ops->compat_get)
138			ret = ops->compat_get(sk, val, opt, len);
139		else
140			ret = ops->get(sk, val, opt, len);
141	} else {
142		if (ops->compat_set)
143			ret = ops->compat_set(sk, val, opt, *len);
144		else
145			ret = ops->set(sk, val, opt, *len);
146	}
147
148	module_put(ops->owner);
149	return ret;
150}
151
152int compat_nf_setsockopt(struct sock *sk, u_int8_t pf,
153		int val, char __user *opt, unsigned int len)
154{
155	return compat_nf_sockopt(sk, pf, val, opt, &len, 0);
156}
157EXPORT_SYMBOL(compat_nf_setsockopt);
158
159int compat_nf_getsockopt(struct sock *sk, u_int8_t pf,
160		int val, char __user *opt, int *len)
161{
162	return compat_nf_sockopt(sk, pf, val, opt, len, 1);
163}
164EXPORT_SYMBOL(compat_nf_getsockopt);
165#endif
166