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f9e815b3 HW |
1 | /* Netfilter messages via netlink socket. Allows for user space |
2 | * protocol helpers and general trouble making from userspace. | |
3 | * | |
4 | * (C) 2001 by Jay Schulist <jschlst@samba.org>, | |
5 | * (C) 2002-2005 by Harald Welte <laforge@gnumonks.org> | |
67ca3966 | 6 | * (C) 2005,2007 by Pablo Neira Ayuso <pablo@netfilter.org> |
f9e815b3 HW |
7 | * |
8 | * Initial netfilter messages via netlink development funded and | |
9 | * generally made possible by Network Robots, Inc. (www.networkrobots.com) | |
10 | * | |
11 | * Further development of this code funded by Astaro AG (http://www.astaro.com) | |
12 | * | |
13 | * This software may be used and distributed according to the terms | |
14 | * of the GNU General Public License, incorporated herein by reference. | |
15 | */ | |
16 | ||
f9e815b3 HW |
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> | |
f9e815b3 HW |
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> | |
a3c5029c | 31 | #include <net/netlink.h> |
f9e815b3 | 32 | #include <linux/init.h> |
f9e815b3 | 33 | |
f9e815b3 HW |
34 | #include <linux/netlink.h> |
35 | #include <linux/netfilter/nfnetlink.h> | |
36 | ||
37 | MODULE_LICENSE("GPL"); | |
4fdb3bb7 HW |
38 | MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>"); |
39 | MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NETFILTER); | |
f9e815b3 HW |
40 | |
41 | static char __initdata nfversion[] = "0.30"; | |
42 | ||
f9e815b3 | 43 | static struct sock *nfnl = NULL; |
7c8d4cb4 | 44 | static const struct nfnetlink_subsystem *subsys_table[NFNL_SUBSYS_COUNT]; |
a3c5029c | 45 | static DEFINE_MUTEX(nfnl_mutex); |
f9e815b3 | 46 | |
3b71535f | 47 | static inline void nfnl_lock(void) |
f9e815b3 | 48 | { |
a3c5029c | 49 | mutex_lock(&nfnl_mutex); |
f9e815b3 HW |
50 | } |
51 | ||
3b71535f | 52 | static inline void nfnl_unlock(void) |
a3c5029c PM |
53 | { |
54 | mutex_unlock(&nfnl_mutex); | |
f9e815b3 HW |
55 | } |
56 | ||
7c8d4cb4 | 57 | int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n) |
f9e815b3 | 58 | { |
f9e815b3 | 59 | nfnl_lock(); |
0ab43f84 HW |
60 | if (subsys_table[n->subsys_id]) { |
61 | nfnl_unlock(); | |
62 | return -EBUSY; | |
63 | } | |
f9e815b3 HW |
64 | subsys_table[n->subsys_id] = n; |
65 | nfnl_unlock(); | |
66 | ||
67 | return 0; | |
68 | } | |
f4bc177f | 69 | EXPORT_SYMBOL_GPL(nfnetlink_subsys_register); |
f9e815b3 | 70 | |
7c8d4cb4 | 71 | int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n) |
f9e815b3 | 72 | { |
f9e815b3 HW |
73 | nfnl_lock(); |
74 | subsys_table[n->subsys_id] = NULL; | |
75 | nfnl_unlock(); | |
76 | ||
77 | return 0; | |
78 | } | |
f4bc177f | 79 | EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister); |
f9e815b3 | 80 | |
7c8d4cb4 | 81 | static inline const struct nfnetlink_subsystem *nfnetlink_get_subsys(u_int16_t type) |
f9e815b3 HW |
82 | { |
83 | u_int8_t subsys_id = NFNL_SUBSYS_ID(type); | |
84 | ||
ac0f1d98 | 85 | if (subsys_id >= NFNL_SUBSYS_COUNT) |
f9e815b3 HW |
86 | return NULL; |
87 | ||
88 | return subsys_table[subsys_id]; | |
89 | } | |
90 | ||
7c8d4cb4 PM |
91 | static inline const struct nfnl_callback * |
92 | nfnetlink_find_client(u_int16_t type, const struct nfnetlink_subsystem *ss) | |
f9e815b3 HW |
93 | { |
94 | u_int8_t cb_id = NFNL_MSG_TYPE(type); | |
601e68e1 | 95 | |
67ca3966 | 96 | if (cb_id >= ss->cb_count) |
f9e815b3 | 97 | return NULL; |
f9e815b3 HW |
98 | |
99 | return &ss->cb[cb_id]; | |
100 | } | |
101 | ||
a2427692 PM |
102 | int nfnetlink_has_listeners(unsigned int group) |
103 | { | |
104 | return netlink_has_listeners(nfnl, group); | |
105 | } | |
106 | EXPORT_SYMBOL_GPL(nfnetlink_has_listeners); | |
107 | ||
f9e815b3 HW |
108 | int nfnetlink_send(struct sk_buff *skb, u32 pid, unsigned group, int echo) |
109 | { | |
dd82185f | 110 | return nlmsg_notify(nfnl, skb, pid, group, echo, gfp_any()); |
f9e815b3 | 111 | } |
f4bc177f | 112 | EXPORT_SYMBOL_GPL(nfnetlink_send); |
f9e815b3 HW |
113 | |
114 | int nfnetlink_unicast(struct sk_buff *skb, u_int32_t pid, int flags) | |
115 | { | |
116 | return netlink_unicast(nfnl, skb, pid, flags); | |
117 | } | |
f4bc177f | 118 | EXPORT_SYMBOL_GPL(nfnetlink_unicast); |
f9e815b3 HW |
119 | |
120 | /* Process one complete nfnetlink message. */ | |
1d00a4eb | 121 | static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh) |
f9e815b3 | 122 | { |
7c8d4cb4 PM |
123 | const struct nfnl_callback *nc; |
124 | const struct nfnetlink_subsystem *ss; | |
1d00a4eb | 125 | int type, err; |
f9e815b3 | 126 | |
1d00a4eb TG |
127 | if (security_netlink_recv(skb, CAP_NET_ADMIN)) |
128 | return -EPERM; | |
37d2e7a2 | 129 | |
f9e815b3 | 130 | /* All the messages must at least contain nfgenmsg */ |
67ca3966 | 131 | if (nlh->nlmsg_len < NLMSG_SPACE(sizeof(struct nfgenmsg))) |
f9e815b3 | 132 | return 0; |
f9e815b3 HW |
133 | |
134 | type = nlh->nlmsg_type; | |
135 | ss = nfnetlink_get_subsys(type); | |
0ab43f84 HW |
136 | if (!ss) { |
137 | #ifdef CONFIG_KMOD | |
3b71535f | 138 | nfnl_unlock(); |
37d2e7a2 | 139 | request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type)); |
a3c5029c | 140 | nfnl_lock(); |
37d2e7a2 | 141 | ss = nfnetlink_get_subsys(type); |
0ab43f84 HW |
142 | if (!ss) |
143 | #endif | |
1d00a4eb | 144 | return -EINVAL; |
0ab43f84 | 145 | } |
f9e815b3 HW |
146 | |
147 | nc = nfnetlink_find_client(type, ss); | |
67ca3966 | 148 | if (!nc) |
1d00a4eb | 149 | return -EINVAL; |
f9e815b3 | 150 | |
f9e815b3 | 151 | { |
e3730578 PM |
152 | int min_len = NLMSG_SPACE(sizeof(struct nfgenmsg)); |
153 | u_int8_t cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type); | |
154 | u_int16_t attr_count = ss->cb[cb_id].attr_count; | |
df6fb868 | 155 | struct nlattr *cda[attr_count+1]; |
f9e815b3 | 156 | |
e3730578 PM |
157 | if (likely(nlh->nlmsg_len >= min_len)) { |
158 | struct nlattr *attr = (void *)nlh + NLMSG_ALIGN(min_len); | |
159 | int attrlen = nlh->nlmsg_len - NLMSG_ALIGN(min_len); | |
160 | ||
161 | err = nla_parse(cda, attr_count, attr, attrlen, | |
162 | ss->cb[cb_id].policy); | |
163 | if (err < 0) | |
164 | return err; | |
165 | } else | |
166 | return -EINVAL; | |
601e68e1 | 167 | |
1d00a4eb | 168 | return nc->call(nfnl, skb, nlh, cda); |
f9e815b3 | 169 | } |
f9e815b3 HW |
170 | } |
171 | ||
cd40b7d3 | 172 | static void nfnetlink_rcv(struct sk_buff *skb) |
f9e815b3 | 173 | { |
cd40b7d3 DL |
174 | nfnl_lock(); |
175 | netlink_rcv_skb(skb, &nfnetlink_rcv_msg); | |
176 | nfnl_unlock(); | |
f9e815b3 HW |
177 | } |
178 | ||
395dde20 | 179 | static void __exit nfnetlink_exit(void) |
f9e815b3 HW |
180 | { |
181 | printk("Removing netfilter NETLINK layer.\n"); | |
b7c6ba6e | 182 | netlink_kernel_release(nfnl); |
f9e815b3 HW |
183 | return; |
184 | } | |
185 | ||
395dde20 | 186 | static int __init nfnetlink_init(void) |
f9e815b3 HW |
187 | { |
188 | printk("Netfilter messages via NETLINK v%s.\n", nfversion); | |
189 | ||
b4b51029 | 190 | nfnl = netlink_kernel_create(&init_net, NETLINK_NETFILTER, NFNLGRP_MAX, |
af65bdfc | 191 | nfnetlink_rcv, NULL, THIS_MODULE); |
f9e815b3 HW |
192 | if (!nfnl) { |
193 | printk(KERN_ERR "cannot initialize nfnetlink!\n"); | |
194 | return -1; | |
195 | } | |
196 | ||
197 | return 0; | |
198 | } | |
199 | ||
200 | module_init(nfnetlink_init); | |
201 | module_exit(nfnetlink_exit); |