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
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
|
/* Netfilter messages via netlink socket. Allows for user space
* protocol helpers and general trouble making from userspace.
*
* (C) 2001 by Jay Schulist <jschlst@samba.org>,
* (C) 2002-2005 by Harald Welte <laforge@gnumonks.org>
* (C) 2005,2007 by Pablo Neira Ayuso <pablo@netfilter.org>
*
* Initial netfilter messages via netlink development funded and
* generally made possible by Network Robots, Inc. (www.networkrobots.com)
*
* Further development of this code funded by Astaro AG (http://www.astaro.com)
*
* This software may be used and distributed according to the terms
* of the GNU General Public License, incorporated herein by reference.
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/fcntl.h>
#include <linux/skbuff.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <net/sock.h>
#include <net/netlink.h>
#include <linux/init.h>
#include <linux/netlink.h>
#include <linux/netfilter/nfnetlink.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NETFILTER);
static char __initdata nfversion[] = "0.30";
static struct sock *nfnl = NULL;
static const struct nfnetlink_subsystem *subsys_table[NFNL_SUBSYS_COUNT];
static DEFINE_MUTEX(nfnl_mutex);
void nfnl_lock(void)
{
mutex_lock(&nfnl_mutex);
}
EXPORT_SYMBOL_GPL(nfnl_lock);
void nfnl_unlock(void)
{
mutex_unlock(&nfnl_mutex);
}
EXPORT_SYMBOL_GPL(nfnl_unlock);
int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n)
{
nfnl_lock();
if (subsys_table[n->subsys_id]) {
nfnl_unlock();
return -EBUSY;
}
subsys_table[n->subsys_id] = n;
nfnl_unlock();
return 0;
}
EXPORT_SYMBOL_GPL(nfnetlink_subsys_register);
int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n)
{
nfnl_lock();
subsys_table[n->subsys_id] = NULL;
nfnl_unlock();
return 0;
}
EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister);
static inline const struct nfnetlink_subsystem *nfnetlink_get_subsys(u_int16_t type)
{
u_int8_t subsys_id = NFNL_SUBSYS_ID(type);
if (subsys_id >= NFNL_SUBSYS_COUNT)
return NULL;
return subsys_table[subsys_id];
}
static inline const struct nfnl_callback *
nfnetlink_find_client(u_int16_t type, const struct nfnetlink_subsystem *ss)
{
u_int8_t cb_id = NFNL_MSG_TYPE(type);
if (cb_id >= ss->cb_count)
return NULL;
return &ss->cb[cb_id];
}
int nfnetlink_has_listeners(unsigned int group)
{
return netlink_has_listeners(nfnl, group);
}
EXPORT_SYMBOL_GPL(nfnetlink_has_listeners);
int nfnetlink_send(struct sk_buff *skb, u32 pid,
unsigned group, int echo, gfp_t flags)
{
return nlmsg_notify(nfnl, skb, pid, group, echo, flags);
}
EXPORT_SYMBOL_GPL(nfnetlink_send);
void nfnetlink_set_err(u32 pid, u32 group, int error)
{
netlink_set_err(nfnl, pid, group, error);
}
EXPORT_SYMBOL_GPL(nfnetlink_set_err);
int nfnetlink_unicast(struct sk_buff *skb, u_int32_t pid, int flags)
{
return netlink_unicast(nfnl, skb, pid, flags);
}
EXPORT_SYMBOL_GPL(nfnetlink_unicast);
/* Process one complete nfnetlink message. */
static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
{
const struct nfnl_callback *nc;
const struct nfnetlink_subsystem *ss;
int type, err;
if (security_netlink_recv(skb, CAP_NET_ADMIN))
return -EPERM;
/* All the messages must at least contain nfgenmsg */
if (nlh->nlmsg_len < NLMSG_LENGTH(sizeof(struct nfgenmsg)))
return 0;
type = nlh->nlmsg_type;
replay:
ss = nfnetlink_get_subsys(type);
if (!ss) {
#ifdef CONFIG_MODULES
nfnl_unlock();
request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type));
nfnl_lock();
ss = nfnetlink_get_subsys(type);
if (!ss)
#endif
return -EINVAL;
}
nc = nfnetlink_find_client(type, ss);
if (!nc)
return -EINVAL;
{
int min_len = NLMSG_SPACE(sizeof(struct nfgenmsg));
u_int8_t cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
struct nlattr *cda[ss->cb[cb_id].attr_count + 1];
struct nlattr *attr = (void *)nlh + min_len;
int attrlen = nlh->nlmsg_len - min_len;
err = nla_parse(cda, ss->cb[cb_id].attr_count,
attr, attrlen, ss->cb[cb_id].policy);
if (err < 0)
return err;
err = nc->call(nfnl, skb, nlh, cda);
if (err == -EAGAIN)
goto replay;
return err;
}
}
static void nfnetlink_rcv(struct sk_buff *skb)
{
nfnl_lock();
netlink_rcv_skb(skb, &nfnetlink_rcv_msg);
nfnl_unlock();
}
static void __exit nfnetlink_exit(void)
{
printk("Removing netfilter NETLINK layer.\n");
netlink_kernel_release(nfnl);
return;
}
static int __init nfnetlink_init(void)
{
printk("Netfilter messages via NETLINK v%s.\n", nfversion);
nfnl = netlink_kernel_create(&init_net, NETLINK_NETFILTER, NFNLGRP_MAX,
nfnetlink_rcv, NULL, THIS_MODULE);
if (!nfnl) {
printk(KERN_ERR "cannot initialize nfnetlink!\n");
return -ENOMEM;
}
return 0;
}
module_init(nfnetlink_init);
module_exit(nfnetlink_exit);
|
