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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 | |
e6a7d3c0 | 47 | void nfnl_lock(void) |
f9e815b3 | 48 | { |
a3c5029c | 49 | mutex_lock(&nfnl_mutex); |
f9e815b3 | 50 | } |
e6a7d3c0 | 51 | EXPORT_SYMBOL_GPL(nfnl_lock); |
f9e815b3 | 52 | |
e6a7d3c0 | 53 | void nfnl_unlock(void) |
a3c5029c PM |
54 | { |
55 | mutex_unlock(&nfnl_mutex); | |
f9e815b3 | 56 | } |
e6a7d3c0 | 57 | EXPORT_SYMBOL_GPL(nfnl_unlock); |
f9e815b3 | 58 | |
7c8d4cb4 | 59 | int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n) |
f9e815b3 | 60 | { |
f9e815b3 | 61 | nfnl_lock(); |
0ab43f84 HW |
62 | if (subsys_table[n->subsys_id]) { |
63 | nfnl_unlock(); | |
64 | return -EBUSY; | |
65 | } | |
f9e815b3 HW |
66 | subsys_table[n->subsys_id] = n; |
67 | nfnl_unlock(); | |
68 | ||
69 | return 0; | |
70 | } | |
f4bc177f | 71 | EXPORT_SYMBOL_GPL(nfnetlink_subsys_register); |
f9e815b3 | 72 | |
7c8d4cb4 | 73 | int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n) |
f9e815b3 | 74 | { |
f9e815b3 HW |
75 | nfnl_lock(); |
76 | subsys_table[n->subsys_id] = NULL; | |
77 | nfnl_unlock(); | |
78 | ||
79 | return 0; | |
80 | } | |
f4bc177f | 81 | EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister); |
f9e815b3 | 82 | |
7c8d4cb4 | 83 | static inline const struct nfnetlink_subsystem *nfnetlink_get_subsys(u_int16_t type) |
f9e815b3 HW |
84 | { |
85 | u_int8_t subsys_id = NFNL_SUBSYS_ID(type); | |
86 | ||
ac0f1d98 | 87 | if (subsys_id >= NFNL_SUBSYS_COUNT) |
f9e815b3 HW |
88 | return NULL; |
89 | ||
90 | return subsys_table[subsys_id]; | |
91 | } | |
92 | ||
7c8d4cb4 PM |
93 | static inline const struct nfnl_callback * |
94 | nfnetlink_find_client(u_int16_t type, const struct nfnetlink_subsystem *ss) | |
f9e815b3 HW |
95 | { |
96 | u_int8_t cb_id = NFNL_MSG_TYPE(type); | |
601e68e1 | 97 | |
67ca3966 | 98 | if (cb_id >= ss->cb_count) |
f9e815b3 | 99 | return NULL; |
f9e815b3 HW |
100 | |
101 | return &ss->cb[cb_id]; | |
102 | } | |
103 | ||
a2427692 PM |
104 | int nfnetlink_has_listeners(unsigned int group) |
105 | { | |
106 | return netlink_has_listeners(nfnl, group); | |
107 | } | |
108 | EXPORT_SYMBOL_GPL(nfnetlink_has_listeners); | |
109 | ||
f9e815b3 HW |
110 | int nfnetlink_send(struct sk_buff *skb, u32 pid, unsigned group, int echo) |
111 | { | |
dd82185f | 112 | return nlmsg_notify(nfnl, skb, pid, group, echo, gfp_any()); |
f9e815b3 | 113 | } |
f4bc177f | 114 | EXPORT_SYMBOL_GPL(nfnetlink_send); |
f9e815b3 HW |
115 | |
116 | int nfnetlink_unicast(struct sk_buff *skb, u_int32_t pid, int flags) | |
117 | { | |
118 | return netlink_unicast(nfnl, skb, pid, flags); | |
119 | } | |
f4bc177f | 120 | EXPORT_SYMBOL_GPL(nfnetlink_unicast); |
f9e815b3 HW |
121 | |
122 | /* Process one complete nfnetlink message. */ | |
1d00a4eb | 123 | static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh) |
f9e815b3 | 124 | { |
7c8d4cb4 PM |
125 | const struct nfnl_callback *nc; |
126 | const struct nfnetlink_subsystem *ss; | |
1d00a4eb | 127 | int type, err; |
f9e815b3 | 128 | |
1d00a4eb TG |
129 | if (security_netlink_recv(skb, CAP_NET_ADMIN)) |
130 | return -EPERM; | |
37d2e7a2 | 131 | |
f9e815b3 | 132 | /* All the messages must at least contain nfgenmsg */ |
67ca3966 | 133 | if (nlh->nlmsg_len < NLMSG_SPACE(sizeof(struct nfgenmsg))) |
f9e815b3 | 134 | return 0; |
f9e815b3 HW |
135 | |
136 | type = nlh->nlmsg_type; | |
e6a7d3c0 | 137 | replay: |
f9e815b3 | 138 | ss = nfnetlink_get_subsys(type); |
0ab43f84 | 139 | if (!ss) { |
95a5afca | 140 | #ifdef CONFIG_MODULES |
3b71535f | 141 | nfnl_unlock(); |
37d2e7a2 | 142 | request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type)); |
a3c5029c | 143 | nfnl_lock(); |
37d2e7a2 | 144 | ss = nfnetlink_get_subsys(type); |
0ab43f84 HW |
145 | if (!ss) |
146 | #endif | |
1d00a4eb | 147 | return -EINVAL; |
0ab43f84 | 148 | } |
f9e815b3 HW |
149 | |
150 | nc = nfnetlink_find_client(type, ss); | |
67ca3966 | 151 | if (!nc) |
1d00a4eb | 152 | return -EINVAL; |
f9e815b3 | 153 | |
f9e815b3 | 154 | { |
e3730578 PM |
155 | int min_len = NLMSG_SPACE(sizeof(struct nfgenmsg)); |
156 | u_int8_t cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type); | |
157 | u_int16_t attr_count = ss->cb[cb_id].attr_count; | |
df6fb868 | 158 | struct nlattr *cda[attr_count+1]; |
f9e815b3 | 159 | |
e3730578 PM |
160 | if (likely(nlh->nlmsg_len >= min_len)) { |
161 | struct nlattr *attr = (void *)nlh + NLMSG_ALIGN(min_len); | |
162 | int attrlen = nlh->nlmsg_len - NLMSG_ALIGN(min_len); | |
163 | ||
164 | err = nla_parse(cda, attr_count, attr, attrlen, | |
165 | ss->cb[cb_id].policy); | |
166 | if (err < 0) | |
167 | return err; | |
168 | } else | |
169 | return -EINVAL; | |
601e68e1 | 170 | |
e6a7d3c0 PNA |
171 | err = nc->call(nfnl, skb, nlh, cda); |
172 | if (err == -EAGAIN) | |
173 | goto replay; | |
174 | return err; | |
f9e815b3 | 175 | } |
f9e815b3 HW |
176 | } |
177 | ||
cd40b7d3 | 178 | static void nfnetlink_rcv(struct sk_buff *skb) |
f9e815b3 | 179 | { |
cd40b7d3 DL |
180 | nfnl_lock(); |
181 | netlink_rcv_skb(skb, &nfnetlink_rcv_msg); | |
182 | nfnl_unlock(); | |
f9e815b3 HW |
183 | } |
184 | ||
395dde20 | 185 | static void __exit nfnetlink_exit(void) |
f9e815b3 HW |
186 | { |
187 | printk("Removing netfilter NETLINK layer.\n"); | |
b7c6ba6e | 188 | netlink_kernel_release(nfnl); |
f9e815b3 HW |
189 | return; |
190 | } | |
191 | ||
395dde20 | 192 | static int __init nfnetlink_init(void) |
f9e815b3 HW |
193 | { |
194 | printk("Netfilter messages via NETLINK v%s.\n", nfversion); | |
195 | ||
b4b51029 | 196 | nfnl = netlink_kernel_create(&init_net, NETLINK_NETFILTER, NFNLGRP_MAX, |
af65bdfc | 197 | nfnetlink_rcv, NULL, THIS_MODULE); |
f9e815b3 HW |
198 | if (!nfnl) { |
199 | printk(KERN_ERR "cannot initialize nfnetlink!\n"); | |
200 | return -1; | |
201 | } | |
202 | ||
203 | return 0; | |
204 | } | |
205 | ||
206 | module_init(nfnetlink_init); | |
207 | module_exit(nfnetlink_exit); |