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 | 26 | #include <net/sock.h> |
a3c5029c | 27 | #include <net/netlink.h> |
f9e815b3 | 28 | #include <linux/init.h> |
f9e815b3 | 29 | |
f9e815b3 HW |
30 | #include <linux/netlink.h> |
31 | #include <linux/netfilter/nfnetlink.h> | |
32 | ||
33 | MODULE_LICENSE("GPL"); | |
4fdb3bb7 HW |
34 | MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>"); |
35 | MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NETFILTER); | |
f9e815b3 HW |
36 | |
37 | static char __initdata nfversion[] = "0.30"; | |
38 | ||
6b75e3e8 | 39 | static const struct nfnetlink_subsystem __rcu *subsys_table[NFNL_SUBSYS_COUNT]; |
a3c5029c | 40 | static DEFINE_MUTEX(nfnl_mutex); |
f9e815b3 | 41 | |
e6a7d3c0 | 42 | void nfnl_lock(void) |
f9e815b3 | 43 | { |
a3c5029c | 44 | mutex_lock(&nfnl_mutex); |
f9e815b3 | 45 | } |
e6a7d3c0 | 46 | EXPORT_SYMBOL_GPL(nfnl_lock); |
f9e815b3 | 47 | |
e6a7d3c0 | 48 | void nfnl_unlock(void) |
a3c5029c PM |
49 | { |
50 | mutex_unlock(&nfnl_mutex); | |
f9e815b3 | 51 | } |
e6a7d3c0 | 52 | EXPORT_SYMBOL_GPL(nfnl_unlock); |
f9e815b3 | 53 | |
7c8d4cb4 | 54 | int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n) |
f9e815b3 | 55 | { |
f9e815b3 | 56 | nfnl_lock(); |
0ab43f84 HW |
57 | if (subsys_table[n->subsys_id]) { |
58 | nfnl_unlock(); | |
59 | return -EBUSY; | |
60 | } | |
cf778b00 | 61 | rcu_assign_pointer(subsys_table[n->subsys_id], n); |
f9e815b3 HW |
62 | nfnl_unlock(); |
63 | ||
64 | return 0; | |
65 | } | |
f4bc177f | 66 | EXPORT_SYMBOL_GPL(nfnetlink_subsys_register); |
f9e815b3 | 67 | |
7c8d4cb4 | 68 | int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n) |
f9e815b3 | 69 | { |
f9e815b3 HW |
70 | nfnl_lock(); |
71 | subsys_table[n->subsys_id] = NULL; | |
72 | nfnl_unlock(); | |
6b75e3e8 | 73 | synchronize_rcu(); |
f9e815b3 HW |
74 | return 0; |
75 | } | |
f4bc177f | 76 | EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister); |
f9e815b3 | 77 | |
7c8d4cb4 | 78 | static inline const struct nfnetlink_subsystem *nfnetlink_get_subsys(u_int16_t type) |
f9e815b3 HW |
79 | { |
80 | u_int8_t subsys_id = NFNL_SUBSYS_ID(type); | |
81 | ||
ac0f1d98 | 82 | if (subsys_id >= NFNL_SUBSYS_COUNT) |
f9e815b3 HW |
83 | return NULL; |
84 | ||
6b75e3e8 | 85 | return rcu_dereference(subsys_table[subsys_id]); |
f9e815b3 HW |
86 | } |
87 | ||
7c8d4cb4 PM |
88 | static inline const struct nfnl_callback * |
89 | nfnetlink_find_client(u_int16_t type, const struct nfnetlink_subsystem *ss) | |
f9e815b3 HW |
90 | { |
91 | u_int8_t cb_id = NFNL_MSG_TYPE(type); | |
601e68e1 | 92 | |
67ca3966 | 93 | if (cb_id >= ss->cb_count) |
f9e815b3 | 94 | return NULL; |
f9e815b3 HW |
95 | |
96 | return &ss->cb[cb_id]; | |
97 | } | |
98 | ||
cd8c20b6 | 99 | int nfnetlink_has_listeners(struct net *net, unsigned int group) |
a2427692 | 100 | { |
cd8c20b6 | 101 | return netlink_has_listeners(net->nfnl, group); |
a2427692 PM |
102 | } |
103 | EXPORT_SYMBOL_GPL(nfnetlink_has_listeners); | |
104 | ||
cd8c20b6 | 105 | int nfnetlink_send(struct sk_buff *skb, struct net *net, u32 pid, |
95c96174 | 106 | unsigned int group, int echo, gfp_t flags) |
f9e815b3 | 107 | { |
cd8c20b6 | 108 | return nlmsg_notify(net->nfnl, skb, pid, group, echo, flags); |
f9e815b3 | 109 | } |
f4bc177f | 110 | EXPORT_SYMBOL_GPL(nfnetlink_send); |
f9e815b3 | 111 | |
37b7ef72 | 112 | int nfnetlink_set_err(struct net *net, u32 pid, u32 group, int error) |
dd5b6ce6 | 113 | { |
37b7ef72 | 114 | return netlink_set_err(net->nfnl, pid, group, error); |
dd5b6ce6 PNA |
115 | } |
116 | EXPORT_SYMBOL_GPL(nfnetlink_set_err); | |
117 | ||
cd8c20b6 | 118 | int nfnetlink_unicast(struct sk_buff *skb, struct net *net, u_int32_t pid, int flags) |
f9e815b3 | 119 | { |
cd8c20b6 | 120 | return netlink_unicast(net->nfnl, skb, pid, flags); |
f9e815b3 | 121 | } |
f4bc177f | 122 | EXPORT_SYMBOL_GPL(nfnetlink_unicast); |
f9e815b3 HW |
123 | |
124 | /* Process one complete nfnetlink message. */ | |
1d00a4eb | 125 | static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh) |
f9e815b3 | 126 | { |
cd8c20b6 | 127 | struct net *net = sock_net(skb->sk); |
7c8d4cb4 PM |
128 | const struct nfnl_callback *nc; |
129 | const struct nfnetlink_subsystem *ss; | |
1d00a4eb | 130 | int type, err; |
f9e815b3 | 131 | |
fd778461 | 132 | if (!capable(CAP_NET_ADMIN)) |
1d00a4eb | 133 | return -EPERM; |
37d2e7a2 | 134 | |
f9e815b3 | 135 | /* All the messages must at least contain nfgenmsg */ |
f49c857f | 136 | if (nlh->nlmsg_len < NLMSG_LENGTH(sizeof(struct nfgenmsg))) |
f9e815b3 | 137 | return 0; |
f9e815b3 HW |
138 | |
139 | type = nlh->nlmsg_type; | |
e6a7d3c0 | 140 | replay: |
6b75e3e8 | 141 | rcu_read_lock(); |
f9e815b3 | 142 | ss = nfnetlink_get_subsys(type); |
0ab43f84 | 143 | if (!ss) { |
95a5afca | 144 | #ifdef CONFIG_MODULES |
6b75e3e8 | 145 | rcu_read_unlock(); |
37d2e7a2 | 146 | request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type)); |
6b75e3e8 | 147 | rcu_read_lock(); |
37d2e7a2 | 148 | ss = nfnetlink_get_subsys(type); |
0ab43f84 HW |
149 | if (!ss) |
150 | #endif | |
6b75e3e8 ED |
151 | { |
152 | rcu_read_unlock(); | |
1d00a4eb | 153 | return -EINVAL; |
6b75e3e8 | 154 | } |
0ab43f84 | 155 | } |
f9e815b3 HW |
156 | |
157 | nc = nfnetlink_find_client(type, ss); | |
6b75e3e8 ED |
158 | if (!nc) { |
159 | rcu_read_unlock(); | |
1d00a4eb | 160 | return -EINVAL; |
6b75e3e8 | 161 | } |
f9e815b3 | 162 | |
f9e815b3 | 163 | { |
e3730578 PM |
164 | int min_len = NLMSG_SPACE(sizeof(struct nfgenmsg)); |
165 | u_int8_t cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type); | |
f49c857f PNA |
166 | struct nlattr *cda[ss->cb[cb_id].attr_count + 1]; |
167 | struct nlattr *attr = (void *)nlh + min_len; | |
168 | int attrlen = nlh->nlmsg_len - min_len; | |
169 | ||
170 | err = nla_parse(cda, ss->cb[cb_id].attr_count, | |
171 | attr, attrlen, ss->cb[cb_id].policy); | |
4009e188 TB |
172 | if (err < 0) { |
173 | rcu_read_unlock(); | |
f49c857f | 174 | return err; |
4009e188 | 175 | } |
601e68e1 | 176 | |
6b75e3e8 ED |
177 | if (nc->call_rcu) { |
178 | err = nc->call_rcu(net->nfnl, skb, nlh, | |
179 | (const struct nlattr **)cda); | |
180 | rcu_read_unlock(); | |
181 | } else { | |
182 | rcu_read_unlock(); | |
183 | nfnl_lock(); | |
184 | if (rcu_dereference_protected( | |
185 | subsys_table[NFNL_SUBSYS_ID(type)], | |
186 | lockdep_is_held(&nfnl_mutex)) != ss || | |
187 | nfnetlink_find_client(type, ss) != nc) | |
188 | err = -EAGAIN; | |
189 | else | |
190 | err = nc->call(net->nfnl, skb, nlh, | |
191 | (const struct nlattr **)cda); | |
192 | nfnl_unlock(); | |
193 | } | |
e6a7d3c0 PNA |
194 | if (err == -EAGAIN) |
195 | goto replay; | |
196 | return err; | |
f9e815b3 | 197 | } |
f9e815b3 HW |
198 | } |
199 | ||
cd40b7d3 | 200 | static void nfnetlink_rcv(struct sk_buff *skb) |
f9e815b3 | 201 | { |
cd40b7d3 | 202 | netlink_rcv_skb(skb, &nfnetlink_rcv_msg); |
f9e815b3 HW |
203 | } |
204 | ||
cd8c20b6 | 205 | static int __net_init nfnetlink_net_init(struct net *net) |
f9e815b3 | 206 | { |
cd8c20b6 AD |
207 | struct sock *nfnl; |
208 | ||
209 | nfnl = netlink_kernel_create(net, NETLINK_NETFILTER, NFNLGRP_MAX, | |
210 | nfnetlink_rcv, NULL, THIS_MODULE); | |
211 | if (!nfnl) | |
212 | return -ENOMEM; | |
213 | net->nfnl_stash = nfnl; | |
cf778b00 | 214 | rcu_assign_pointer(net->nfnl, nfnl); |
cd8c20b6 | 215 | return 0; |
f9e815b3 HW |
216 | } |
217 | ||
cd8c20b6 | 218 | static void __net_exit nfnetlink_net_exit_batch(struct list_head *net_exit_list) |
f9e815b3 | 219 | { |
cd8c20b6 | 220 | struct net *net; |
f9e815b3 | 221 | |
cd8c20b6 | 222 | list_for_each_entry(net, net_exit_list, exit_list) |
a9b3cd7f | 223 | RCU_INIT_POINTER(net->nfnl, NULL); |
cd8c20b6 AD |
224 | synchronize_net(); |
225 | list_for_each_entry(net, net_exit_list, exit_list) | |
226 | netlink_kernel_release(net->nfnl_stash); | |
227 | } | |
f9e815b3 | 228 | |
cd8c20b6 AD |
229 | static struct pernet_operations nfnetlink_net_ops = { |
230 | .init = nfnetlink_net_init, | |
231 | .exit_batch = nfnetlink_net_exit_batch, | |
232 | }; | |
233 | ||
234 | static int __init nfnetlink_init(void) | |
235 | { | |
654d0fbd | 236 | pr_info("Netfilter messages via NETLINK v%s.\n", nfversion); |
cd8c20b6 | 237 | return register_pernet_subsys(&nfnetlink_net_ops); |
f9e815b3 HW |
238 | } |
239 | ||
cd8c20b6 AD |
240 | static void __exit nfnetlink_exit(void) |
241 | { | |
654d0fbd | 242 | pr_info("Removing netfilter NETLINK layer.\n"); |
cd8c20b6 AD |
243 | unregister_pernet_subsys(&nfnetlink_net_ops); |
244 | } | |
f9e815b3 HW |
245 | module_init(nfnetlink_init); |
246 | module_exit(nfnetlink_exit); |