Commit | Line | Data |
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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> | |
f9e815b3 HW |
21 | #include <linux/string.h> |
22 | #include <linux/sockios.h> | |
23 | #include <linux/net.h> | |
f9e815b3 HW |
24 | #include <linux/skbuff.h> |
25 | #include <asm/uaccess.h> | |
f9e815b3 HW |
26 | #include <net/sock.h> |
27 | #include <linux/init.h> | |
f9e815b3 | 28 | |
573ce260 | 29 | #include <net/netlink.h> |
f9e815b3 HW |
30 | #include <linux/netfilter/nfnetlink.h> |
31 | ||
32 | MODULE_LICENSE("GPL"); | |
4fdb3bb7 HW |
33 | MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>"); |
34 | MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NETFILTER); | |
f9e815b3 HW |
35 | |
36 | static char __initdata nfversion[] = "0.30"; | |
37 | ||
c14b78e7 PNA |
38 | static struct { |
39 | struct mutex mutex; | |
40 | const struct nfnetlink_subsystem __rcu *subsys; | |
41 | } table[NFNL_SUBSYS_COUNT]; | |
f9e815b3 | 42 | |
03292745 PNA |
43 | static const int nfnl_group2type[NFNLGRP_MAX+1] = { |
44 | [NFNLGRP_CONNTRACK_NEW] = NFNL_SUBSYS_CTNETLINK, | |
45 | [NFNLGRP_CONNTRACK_UPDATE] = NFNL_SUBSYS_CTNETLINK, | |
46 | [NFNLGRP_CONNTRACK_DESTROY] = NFNL_SUBSYS_CTNETLINK, | |
47 | [NFNLGRP_CONNTRACK_EXP_NEW] = NFNL_SUBSYS_CTNETLINK_EXP, | |
48 | [NFNLGRP_CONNTRACK_EXP_UPDATE] = NFNL_SUBSYS_CTNETLINK_EXP, | |
49 | [NFNLGRP_CONNTRACK_EXP_DESTROY] = NFNL_SUBSYS_CTNETLINK_EXP, | |
50 | }; | |
51 | ||
c14b78e7 | 52 | void nfnl_lock(__u8 subsys_id) |
f9e815b3 | 53 | { |
c14b78e7 | 54 | mutex_lock(&table[subsys_id].mutex); |
f9e815b3 | 55 | } |
e6a7d3c0 | 56 | EXPORT_SYMBOL_GPL(nfnl_lock); |
f9e815b3 | 57 | |
c14b78e7 | 58 | void nfnl_unlock(__u8 subsys_id) |
a3c5029c | 59 | { |
c14b78e7 | 60 | mutex_unlock(&table[subsys_id].mutex); |
f9e815b3 | 61 | } |
e6a7d3c0 | 62 | EXPORT_SYMBOL_GPL(nfnl_unlock); |
f9e815b3 | 63 | |
7c8d4cb4 | 64 | int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n) |
f9e815b3 | 65 | { |
c14b78e7 PNA |
66 | nfnl_lock(n->subsys_id); |
67 | if (table[n->subsys_id].subsys) { | |
68 | nfnl_unlock(n->subsys_id); | |
0ab43f84 HW |
69 | return -EBUSY; |
70 | } | |
c14b78e7 PNA |
71 | rcu_assign_pointer(table[n->subsys_id].subsys, n); |
72 | nfnl_unlock(n->subsys_id); | |
f9e815b3 HW |
73 | |
74 | return 0; | |
75 | } | |
f4bc177f | 76 | EXPORT_SYMBOL_GPL(nfnetlink_subsys_register); |
f9e815b3 | 77 | |
7c8d4cb4 | 78 | int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n) |
f9e815b3 | 79 | { |
c14b78e7 PNA |
80 | nfnl_lock(n->subsys_id); |
81 | table[n->subsys_id].subsys = NULL; | |
82 | nfnl_unlock(n->subsys_id); | |
6b75e3e8 | 83 | synchronize_rcu(); |
f9e815b3 HW |
84 | return 0; |
85 | } | |
f4bc177f | 86 | EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister); |
f9e815b3 | 87 | |
7c8d4cb4 | 88 | static inline const struct nfnetlink_subsystem *nfnetlink_get_subsys(u_int16_t type) |
f9e815b3 HW |
89 | { |
90 | u_int8_t subsys_id = NFNL_SUBSYS_ID(type); | |
91 | ||
ac0f1d98 | 92 | if (subsys_id >= NFNL_SUBSYS_COUNT) |
f9e815b3 HW |
93 | return NULL; |
94 | ||
c14b78e7 | 95 | return rcu_dereference(table[subsys_id].subsys); |
f9e815b3 HW |
96 | } |
97 | ||
7c8d4cb4 PM |
98 | static inline const struct nfnl_callback * |
99 | nfnetlink_find_client(u_int16_t type, const struct nfnetlink_subsystem *ss) | |
f9e815b3 HW |
100 | { |
101 | u_int8_t cb_id = NFNL_MSG_TYPE(type); | |
601e68e1 | 102 | |
67ca3966 | 103 | if (cb_id >= ss->cb_count) |
f9e815b3 | 104 | return NULL; |
f9e815b3 HW |
105 | |
106 | return &ss->cb[cb_id]; | |
107 | } | |
108 | ||
cd8c20b6 | 109 | int nfnetlink_has_listeners(struct net *net, unsigned int group) |
a2427692 | 110 | { |
cd8c20b6 | 111 | return netlink_has_listeners(net->nfnl, group); |
a2427692 PM |
112 | } |
113 | EXPORT_SYMBOL_GPL(nfnetlink_has_listeners); | |
114 | ||
cd8c20b6 | 115 | int nfnetlink_send(struct sk_buff *skb, struct net *net, u32 pid, |
95c96174 | 116 | unsigned int group, int echo, gfp_t flags) |
f9e815b3 | 117 | { |
cd8c20b6 | 118 | return nlmsg_notify(net->nfnl, skb, pid, group, echo, flags); |
f9e815b3 | 119 | } |
f4bc177f | 120 | EXPORT_SYMBOL_GPL(nfnetlink_send); |
f9e815b3 | 121 | |
37b7ef72 | 122 | int nfnetlink_set_err(struct net *net, u32 pid, u32 group, int error) |
dd5b6ce6 | 123 | { |
37b7ef72 | 124 | return netlink_set_err(net->nfnl, pid, group, error); |
dd5b6ce6 PNA |
125 | } |
126 | EXPORT_SYMBOL_GPL(nfnetlink_set_err); | |
127 | ||
cd8c20b6 | 128 | int nfnetlink_unicast(struct sk_buff *skb, struct net *net, u_int32_t pid, int flags) |
f9e815b3 | 129 | { |
cd8c20b6 | 130 | return netlink_unicast(net->nfnl, skb, pid, flags); |
f9e815b3 | 131 | } |
f4bc177f | 132 | EXPORT_SYMBOL_GPL(nfnetlink_unicast); |
f9e815b3 HW |
133 | |
134 | /* Process one complete nfnetlink message. */ | |
1d00a4eb | 135 | static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh) |
f9e815b3 | 136 | { |
cd8c20b6 | 137 | struct net *net = sock_net(skb->sk); |
7c8d4cb4 PM |
138 | const struct nfnl_callback *nc; |
139 | const struct nfnetlink_subsystem *ss; | |
1d00a4eb | 140 | int type, err; |
f9e815b3 | 141 | |
df008c91 | 142 | if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) |
1d00a4eb | 143 | return -EPERM; |
37d2e7a2 | 144 | |
f9e815b3 | 145 | /* All the messages must at least contain nfgenmsg */ |
573ce260 | 146 | if (nlmsg_len(nlh) < sizeof(struct nfgenmsg)) |
f9e815b3 | 147 | return 0; |
f9e815b3 HW |
148 | |
149 | type = nlh->nlmsg_type; | |
e6a7d3c0 | 150 | replay: |
6b75e3e8 | 151 | rcu_read_lock(); |
f9e815b3 | 152 | ss = nfnetlink_get_subsys(type); |
0ab43f84 | 153 | if (!ss) { |
95a5afca | 154 | #ifdef CONFIG_MODULES |
6b75e3e8 | 155 | rcu_read_unlock(); |
37d2e7a2 | 156 | request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type)); |
6b75e3e8 | 157 | rcu_read_lock(); |
37d2e7a2 | 158 | ss = nfnetlink_get_subsys(type); |
0ab43f84 HW |
159 | if (!ss) |
160 | #endif | |
6b75e3e8 ED |
161 | { |
162 | rcu_read_unlock(); | |
1d00a4eb | 163 | return -EINVAL; |
6b75e3e8 | 164 | } |
0ab43f84 | 165 | } |
f9e815b3 HW |
166 | |
167 | nc = nfnetlink_find_client(type, ss); | |
6b75e3e8 ED |
168 | if (!nc) { |
169 | rcu_read_unlock(); | |
1d00a4eb | 170 | return -EINVAL; |
6b75e3e8 | 171 | } |
f9e815b3 | 172 | |
f9e815b3 | 173 | { |
573ce260 | 174 | int min_len = nlmsg_total_size(sizeof(struct nfgenmsg)); |
e3730578 | 175 | u_int8_t cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type); |
f49c857f PNA |
176 | struct nlattr *cda[ss->cb[cb_id].attr_count + 1]; |
177 | struct nlattr *attr = (void *)nlh + min_len; | |
178 | int attrlen = nlh->nlmsg_len - min_len; | |
c14b78e7 | 179 | __u8 subsys_id = NFNL_SUBSYS_ID(type); |
f49c857f PNA |
180 | |
181 | err = nla_parse(cda, ss->cb[cb_id].attr_count, | |
182 | attr, attrlen, ss->cb[cb_id].policy); | |
4009e188 TB |
183 | if (err < 0) { |
184 | rcu_read_unlock(); | |
f49c857f | 185 | return err; |
4009e188 | 186 | } |
601e68e1 | 187 | |
6b75e3e8 ED |
188 | if (nc->call_rcu) { |
189 | err = nc->call_rcu(net->nfnl, skb, nlh, | |
190 | (const struct nlattr **)cda); | |
191 | rcu_read_unlock(); | |
192 | } else { | |
193 | rcu_read_unlock(); | |
c14b78e7 PNA |
194 | nfnl_lock(subsys_id); |
195 | if (rcu_dereference_protected(table[subsys_id].subsys, | |
9df9e783 | 196 | lockdep_is_held(&table[subsys_id].mutex)) != ss || |
6b75e3e8 ED |
197 | nfnetlink_find_client(type, ss) != nc) |
198 | err = -EAGAIN; | |
59560a38 | 199 | else if (nc->call) |
6b75e3e8 ED |
200 | err = nc->call(net->nfnl, skb, nlh, |
201 | (const struct nlattr **)cda); | |
59560a38 TB |
202 | else |
203 | err = -EINVAL; | |
c14b78e7 | 204 | nfnl_unlock(subsys_id); |
6b75e3e8 | 205 | } |
e6a7d3c0 PNA |
206 | if (err == -EAGAIN) |
207 | goto replay; | |
208 | return err; | |
f9e815b3 | 209 | } |
f9e815b3 HW |
210 | } |
211 | ||
cd40b7d3 | 212 | static void nfnetlink_rcv(struct sk_buff *skb) |
f9e815b3 | 213 | { |
cd40b7d3 | 214 | netlink_rcv_skb(skb, &nfnetlink_rcv_msg); |
f9e815b3 HW |
215 | } |
216 | ||
03292745 PNA |
217 | #ifdef CONFIG_MODULES |
218 | static void nfnetlink_bind(int group) | |
219 | { | |
220 | const struct nfnetlink_subsystem *ss; | |
221 | int type = nfnl_group2type[group]; | |
222 | ||
223 | rcu_read_lock(); | |
224 | ss = nfnetlink_get_subsys(type); | |
225 | if (!ss) { | |
226 | rcu_read_unlock(); | |
227 | request_module("nfnetlink-subsys-%d", type); | |
228 | return; | |
229 | } | |
230 | rcu_read_unlock(); | |
231 | } | |
232 | #endif | |
233 | ||
cd8c20b6 | 234 | static int __net_init nfnetlink_net_init(struct net *net) |
f9e815b3 | 235 | { |
cd8c20b6 | 236 | struct sock *nfnl; |
a31f2d17 PNA |
237 | struct netlink_kernel_cfg cfg = { |
238 | .groups = NFNLGRP_MAX, | |
239 | .input = nfnetlink_rcv, | |
03292745 PNA |
240 | #ifdef CONFIG_MODULES |
241 | .bind = nfnetlink_bind, | |
242 | #endif | |
a31f2d17 | 243 | }; |
cd8c20b6 | 244 | |
9f00d977 | 245 | nfnl = netlink_kernel_create(net, NETLINK_NETFILTER, &cfg); |
cd8c20b6 AD |
246 | if (!nfnl) |
247 | return -ENOMEM; | |
248 | net->nfnl_stash = nfnl; | |
cf778b00 | 249 | rcu_assign_pointer(net->nfnl, nfnl); |
cd8c20b6 | 250 | return 0; |
f9e815b3 HW |
251 | } |
252 | ||
cd8c20b6 | 253 | static void __net_exit nfnetlink_net_exit_batch(struct list_head *net_exit_list) |
f9e815b3 | 254 | { |
cd8c20b6 | 255 | struct net *net; |
f9e815b3 | 256 | |
cd8c20b6 | 257 | list_for_each_entry(net, net_exit_list, exit_list) |
a9b3cd7f | 258 | RCU_INIT_POINTER(net->nfnl, NULL); |
cd8c20b6 AD |
259 | synchronize_net(); |
260 | list_for_each_entry(net, net_exit_list, exit_list) | |
261 | netlink_kernel_release(net->nfnl_stash); | |
262 | } | |
f9e815b3 | 263 | |
cd8c20b6 AD |
264 | static struct pernet_operations nfnetlink_net_ops = { |
265 | .init = nfnetlink_net_init, | |
266 | .exit_batch = nfnetlink_net_exit_batch, | |
267 | }; | |
268 | ||
269 | static int __init nfnetlink_init(void) | |
270 | { | |
c14b78e7 PNA |
271 | int i; |
272 | ||
273 | for (i=0; i<NFNL_SUBSYS_COUNT; i++) | |
274 | mutex_init(&table[i].mutex); | |
275 | ||
654d0fbd | 276 | pr_info("Netfilter messages via NETLINK v%s.\n", nfversion); |
cd8c20b6 | 277 | return register_pernet_subsys(&nfnetlink_net_ops); |
f9e815b3 HW |
278 | } |
279 | ||
cd8c20b6 AD |
280 | static void __exit nfnetlink_exit(void) |
281 | { | |
654d0fbd | 282 | pr_info("Removing netfilter NETLINK layer.\n"); |
cd8c20b6 AD |
283 | unregister_pernet_subsys(&nfnetlink_net_ops); |
284 | } | |
f9e815b3 HW |
285 | module_init(nfnetlink_init); |
286 | module_exit(nfnetlink_exit); |