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17#include <linux/module.h>
18#include <linux/types.h>
19#include <linux/socket.h>
20#include <linux/kernel.h>
21#include <linux/major.h>
22#include <linux/timer.h>
23#include <linux/string.h>
24#include <linux/sockios.h>
25#include <linux/net.h>
26#include <linux/fcntl.h>
27#include <linux/skbuff.h>
28#include <asm/uaccess.h>
29#include <asm/system.h>
30#include <net/sock.h>
31#include <net/netlink.h>
32#include <linux/init.h>
33
34#include <linux/netlink.h>
35#include <linux/netfilter/nfnetlink.h>
36
37MODULE_LICENSE("GPL");
38MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
39MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NETFILTER);
40
41static char __initdata nfversion[] = "0.30";
42
43static struct sock *nfnl = NULL;
44static const struct nfnetlink_subsystem *subsys_table[NFNL_SUBSYS_COUNT];
45static DEFINE_MUTEX(nfnl_mutex);
46
47void nfnl_lock(void)
48{
49 mutex_lock(&nfnl_mutex);
50}
51EXPORT_SYMBOL_GPL(nfnl_lock);
52
53void nfnl_unlock(void)
54{
55 mutex_unlock(&nfnl_mutex);
56}
57EXPORT_SYMBOL_GPL(nfnl_unlock);
58
59int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n)
60{
61 nfnl_lock();
62 if (subsys_table[n->subsys_id]) {
63 nfnl_unlock();
64 return -EBUSY;
65 }
66 subsys_table[n->subsys_id] = n;
67 nfnl_unlock();
68
69 return 0;
70}
71EXPORT_SYMBOL_GPL(nfnetlink_subsys_register);
72
73int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n)
74{
75 nfnl_lock();
76 subsys_table[n->subsys_id] = NULL;
77 nfnl_unlock();
78
79 return 0;
80}
81EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister);
82
83static inline const struct nfnetlink_subsystem *nfnetlink_get_subsys(u_int16_t type)
84{
85 u_int8_t subsys_id = NFNL_SUBSYS_ID(type);
86
87 if (subsys_id >= NFNL_SUBSYS_COUNT)
88 return NULL;
89
90 return subsys_table[subsys_id];
91}
92
93static inline const struct nfnl_callback *
94nfnetlink_find_client(u_int16_t type, const struct nfnetlink_subsystem *ss)
95{
96 u_int8_t cb_id = NFNL_MSG_TYPE(type);
97
98 if (cb_id >= ss->cb_count)
99 return NULL;
100
101 return &ss->cb[cb_id];
102}
103
104int nfnetlink_has_listeners(unsigned int group)
105{
106 return netlink_has_listeners(nfnl, group);
107}
108EXPORT_SYMBOL_GPL(nfnetlink_has_listeners);
109
110int nfnetlink_send(struct sk_buff *skb, u32 pid,
111 unsigned group, int echo, gfp_t flags)
112{
113 return nlmsg_notify(nfnl, skb, pid, group, echo, flags);
114}
115EXPORT_SYMBOL_GPL(nfnetlink_send);
116
117void nfnetlink_set_err(u32 pid, u32 group, int error)
118{
119 netlink_set_err(nfnl, pid, group, error);
120}
121EXPORT_SYMBOL_GPL(nfnetlink_set_err);
122
123int nfnetlink_unicast(struct sk_buff *skb, u_int32_t pid, int flags)
124{
125 return netlink_unicast(nfnl, skb, pid, flags);
126}
127EXPORT_SYMBOL_GPL(nfnetlink_unicast);
128
129
130static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
131{
132 const struct nfnl_callback *nc;
133 const struct nfnetlink_subsystem *ss;
134 int type, err;
135
136 if (security_netlink_recv(skb, CAP_NET_ADMIN))
137 return -EPERM;
138
139
140 if (nlh->nlmsg_len < NLMSG_LENGTH(sizeof(struct nfgenmsg)))
141 return 0;
142
143 type = nlh->nlmsg_type;
144replay:
145 ss = nfnetlink_get_subsys(type);
146 if (!ss) {
147#ifdef CONFIG_MODULES
148 nfnl_unlock();
149 request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type));
150 nfnl_lock();
151 ss = nfnetlink_get_subsys(type);
152 if (!ss)
153#endif
154 return -EINVAL;
155 }
156
157 nc = nfnetlink_find_client(type, ss);
158 if (!nc)
159 return -EINVAL;
160
161 {
162 int min_len = NLMSG_SPACE(sizeof(struct nfgenmsg));
163 u_int8_t cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
164 struct nlattr *cda[ss->cb[cb_id].attr_count + 1];
165 struct nlattr *attr = (void *)nlh + min_len;
166 int attrlen = nlh->nlmsg_len - min_len;
167
168 err = nla_parse(cda, ss->cb[cb_id].attr_count,
169 attr, attrlen, ss->cb[cb_id].policy);
170 if (err < 0)
171 return err;
172
173 err = nc->call(nfnl, skb, nlh, (const struct nlattr **)cda);
174 if (err == -EAGAIN)
175 goto replay;
176 return err;
177 }
178}
179
180static void nfnetlink_rcv(struct sk_buff *skb)
181{
182 nfnl_lock();
183 netlink_rcv_skb(skb, &nfnetlink_rcv_msg);
184 nfnl_unlock();
185}
186
187static void __exit nfnetlink_exit(void)
188{
189 printk("Removing netfilter NETLINK layer.\n");
190 netlink_kernel_release(nfnl);
191 return;
192}
193
194static int __init nfnetlink_init(void)
195{
196 printk("Netfilter messages via NETLINK v%s.\n", nfversion);
197
198 nfnl = netlink_kernel_create(&init_net, NETLINK_NETFILTER, NFNLGRP_MAX,
199 nfnetlink_rcv, NULL, THIS_MODULE);
200 if (!nfnl) {
201 printk(KERN_ERR "cannot initialize nfnetlink!\n");
202 return -ENOMEM;
203 }
204
205 return 0;
206}
207
208module_init(nfnetlink_init);
209module_exit(nfnetlink_exit);
210