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 | ||
3ab1f683 PM |
115 | struct sk_buff *nfnetlink_alloc_skb(struct net *net, unsigned int size, |
116 | u32 dst_portid, gfp_t gfp_mask) | |
117 | { | |
118 | return netlink_alloc_skb(net->nfnl, size, dst_portid, gfp_mask); | |
119 | } | |
120 | EXPORT_SYMBOL_GPL(nfnetlink_alloc_skb); | |
121 | ||
ec464e5d | 122 | int nfnetlink_send(struct sk_buff *skb, struct net *net, u32 portid, |
95c96174 | 123 | unsigned int group, int echo, gfp_t flags) |
f9e815b3 | 124 | { |
ec464e5d | 125 | return nlmsg_notify(net->nfnl, skb, portid, group, echo, flags); |
f9e815b3 | 126 | } |
f4bc177f | 127 | EXPORT_SYMBOL_GPL(nfnetlink_send); |
f9e815b3 | 128 | |
ec464e5d | 129 | int nfnetlink_set_err(struct net *net, u32 portid, u32 group, int error) |
dd5b6ce6 | 130 | { |
ec464e5d | 131 | return netlink_set_err(net->nfnl, portid, group, error); |
dd5b6ce6 PNA |
132 | } |
133 | EXPORT_SYMBOL_GPL(nfnetlink_set_err); | |
134 | ||
ec464e5d PM |
135 | int nfnetlink_unicast(struct sk_buff *skb, struct net *net, u32 portid, |
136 | int flags) | |
f9e815b3 | 137 | { |
ec464e5d | 138 | return netlink_unicast(net->nfnl, skb, portid, flags); |
f9e815b3 | 139 | } |
f4bc177f | 140 | EXPORT_SYMBOL_GPL(nfnetlink_unicast); |
f9e815b3 HW |
141 | |
142 | /* Process one complete nfnetlink message. */ | |
1d00a4eb | 143 | static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh) |
f9e815b3 | 144 | { |
cd8c20b6 | 145 | struct net *net = sock_net(skb->sk); |
7c8d4cb4 PM |
146 | const struct nfnl_callback *nc; |
147 | const struct nfnetlink_subsystem *ss; | |
1d00a4eb | 148 | int type, err; |
f9e815b3 | 149 | |
1141a455 | 150 | if (!netlink_net_capable(skb, CAP_NET_ADMIN)) |
1d00a4eb | 151 | return -EPERM; |
37d2e7a2 | 152 | |
f9e815b3 | 153 | /* All the messages must at least contain nfgenmsg */ |
573ce260 | 154 | if (nlmsg_len(nlh) < sizeof(struct nfgenmsg)) |
f9e815b3 | 155 | return 0; |
f9e815b3 HW |
156 | |
157 | type = nlh->nlmsg_type; | |
e6a7d3c0 | 158 | replay: |
6b75e3e8 | 159 | rcu_read_lock(); |
f9e815b3 | 160 | ss = nfnetlink_get_subsys(type); |
0ab43f84 | 161 | if (!ss) { |
95a5afca | 162 | #ifdef CONFIG_MODULES |
6b75e3e8 | 163 | rcu_read_unlock(); |
37d2e7a2 | 164 | request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type)); |
6b75e3e8 | 165 | rcu_read_lock(); |
37d2e7a2 | 166 | ss = nfnetlink_get_subsys(type); |
0ab43f84 HW |
167 | if (!ss) |
168 | #endif | |
6b75e3e8 ED |
169 | { |
170 | rcu_read_unlock(); | |
1d00a4eb | 171 | return -EINVAL; |
6b75e3e8 | 172 | } |
0ab43f84 | 173 | } |
f9e815b3 HW |
174 | |
175 | nc = nfnetlink_find_client(type, ss); | |
6b75e3e8 ED |
176 | if (!nc) { |
177 | rcu_read_unlock(); | |
1d00a4eb | 178 | return -EINVAL; |
6b75e3e8 | 179 | } |
f9e815b3 | 180 | |
f9e815b3 | 181 | { |
573ce260 | 182 | int min_len = nlmsg_total_size(sizeof(struct nfgenmsg)); |
e3730578 | 183 | u_int8_t cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type); |
f49c857f PNA |
184 | struct nlattr *cda[ss->cb[cb_id].attr_count + 1]; |
185 | struct nlattr *attr = (void *)nlh + min_len; | |
186 | int attrlen = nlh->nlmsg_len - min_len; | |
c14b78e7 | 187 | __u8 subsys_id = NFNL_SUBSYS_ID(type); |
f49c857f PNA |
188 | |
189 | err = nla_parse(cda, ss->cb[cb_id].attr_count, | |
190 | attr, attrlen, ss->cb[cb_id].policy); | |
4009e188 TB |
191 | if (err < 0) { |
192 | rcu_read_unlock(); | |
f49c857f | 193 | return err; |
4009e188 | 194 | } |
601e68e1 | 195 | |
6b75e3e8 ED |
196 | if (nc->call_rcu) { |
197 | err = nc->call_rcu(net->nfnl, skb, nlh, | |
198 | (const struct nlattr **)cda); | |
199 | rcu_read_unlock(); | |
200 | } else { | |
201 | rcu_read_unlock(); | |
c14b78e7 PNA |
202 | nfnl_lock(subsys_id); |
203 | if (rcu_dereference_protected(table[subsys_id].subsys, | |
9df9e783 | 204 | lockdep_is_held(&table[subsys_id].mutex)) != ss || |
6b75e3e8 ED |
205 | nfnetlink_find_client(type, ss) != nc) |
206 | err = -EAGAIN; | |
59560a38 | 207 | else if (nc->call) |
6b75e3e8 ED |
208 | err = nc->call(net->nfnl, skb, nlh, |
209 | (const struct nlattr **)cda); | |
59560a38 TB |
210 | else |
211 | err = -EINVAL; | |
c14b78e7 | 212 | nfnl_unlock(subsys_id); |
6b75e3e8 | 213 | } |
e6a7d3c0 PNA |
214 | if (err == -EAGAIN) |
215 | goto replay; | |
216 | return err; | |
f9e815b3 | 217 | } |
f9e815b3 HW |
218 | } |
219 | ||
cd40b7d3 | 220 | static void nfnetlink_rcv(struct sk_buff *skb) |
f9e815b3 | 221 | { |
cd40b7d3 | 222 | netlink_rcv_skb(skb, &nfnetlink_rcv_msg); |
f9e815b3 HW |
223 | } |
224 | ||
03292745 PNA |
225 | #ifdef CONFIG_MODULES |
226 | static void nfnetlink_bind(int group) | |
227 | { | |
228 | const struct nfnetlink_subsystem *ss; | |
229 | int type = nfnl_group2type[group]; | |
230 | ||
231 | rcu_read_lock(); | |
232 | ss = nfnetlink_get_subsys(type); | |
233 | if (!ss) { | |
234 | rcu_read_unlock(); | |
235 | request_module("nfnetlink-subsys-%d", type); | |
236 | return; | |
237 | } | |
238 | rcu_read_unlock(); | |
239 | } | |
240 | #endif | |
241 | ||
cd8c20b6 | 242 | static int __net_init nfnetlink_net_init(struct net *net) |
f9e815b3 | 243 | { |
cd8c20b6 | 244 | struct sock *nfnl; |
a31f2d17 PNA |
245 | struct netlink_kernel_cfg cfg = { |
246 | .groups = NFNLGRP_MAX, | |
247 | .input = nfnetlink_rcv, | |
03292745 PNA |
248 | #ifdef CONFIG_MODULES |
249 | .bind = nfnetlink_bind, | |
250 | #endif | |
a31f2d17 | 251 | }; |
cd8c20b6 | 252 | |
9f00d977 | 253 | nfnl = netlink_kernel_create(net, NETLINK_NETFILTER, &cfg); |
cd8c20b6 AD |
254 | if (!nfnl) |
255 | return -ENOMEM; | |
256 | net->nfnl_stash = nfnl; | |
cf778b00 | 257 | rcu_assign_pointer(net->nfnl, nfnl); |
cd8c20b6 | 258 | return 0; |
f9e815b3 HW |
259 | } |
260 | ||
cd8c20b6 | 261 | static void __net_exit nfnetlink_net_exit_batch(struct list_head *net_exit_list) |
f9e815b3 | 262 | { |
cd8c20b6 | 263 | struct net *net; |
f9e815b3 | 264 | |
cd8c20b6 | 265 | list_for_each_entry(net, net_exit_list, exit_list) |
a9b3cd7f | 266 | RCU_INIT_POINTER(net->nfnl, NULL); |
cd8c20b6 AD |
267 | synchronize_net(); |
268 | list_for_each_entry(net, net_exit_list, exit_list) | |
269 | netlink_kernel_release(net->nfnl_stash); | |
270 | } | |
f9e815b3 | 271 | |
cd8c20b6 AD |
272 | static struct pernet_operations nfnetlink_net_ops = { |
273 | .init = nfnetlink_net_init, | |
274 | .exit_batch = nfnetlink_net_exit_batch, | |
275 | }; | |
276 | ||
277 | static int __init nfnetlink_init(void) | |
278 | { | |
c14b78e7 PNA |
279 | int i; |
280 | ||
281 | for (i=0; i<NFNL_SUBSYS_COUNT; i++) | |
282 | mutex_init(&table[i].mutex); | |
283 | ||
654d0fbd | 284 | pr_info("Netfilter messages via NETLINK v%s.\n", nfversion); |
cd8c20b6 | 285 | return register_pernet_subsys(&nfnetlink_net_ops); |
f9e815b3 HW |
286 | } |
287 | ||
cd8c20b6 AD |
288 | static void __exit nfnetlink_exit(void) |
289 | { | |
654d0fbd | 290 | pr_info("Removing netfilter NETLINK layer.\n"); |
cd8c20b6 AD |
291 | unregister_pernet_subsys(&nfnetlink_net_ops); |
292 | } | |
f9e815b3 HW |
293 | module_init(nfnetlink_init); |
294 | module_exit(nfnetlink_exit); |