1 /* Netfilter messages via netlink socket. Allows for user space
2 * protocol helpers and general trouble making from userspace.
4 * (C) 2001 by Jay Schulist <jschlst@samba.org>,
5 * (C) 2002-2005 by Harald Welte <laforge@gnumonks.org>
6 * (C) 2005,2007 by Pablo Neira Ayuso <pablo@netfilter.org>
8 * Initial netfilter messages via netlink development funded and
9 * generally made possible by Network Robots, Inc. (www.networkrobots.com)
11 * Further development of this code funded by Astaro AG (http://www.astaro.com)
13 * This software may be used and distributed according to the terms
14 * of the GNU General Public License, incorporated herein by reference.
17 #include <linux/module.h>
18 #include <linux/types.h>
19 #include <linux/socket.h>
20 #include <linux/kernel.h>
21 #include <linux/string.h>
22 #include <linux/sockios.h>
23 #include <linux/net.h>
24 #include <linux/skbuff.h>
25 #include <asm/uaccess.h>
27 #include <linux/init.h>
29 #include <net/netlink.h>
30 #include <linux/netfilter/nfnetlink.h>
32 MODULE_LICENSE("GPL");
33 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
34 MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NETFILTER);
36 static char __initdata nfversion[] = "0.30";
40 const struct nfnetlink_subsystem __rcu *subsys;
41 } table[NFNL_SUBSYS_COUNT];
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,
52 void nfnl_lock(__u8 subsys_id)
54 mutex_lock(&table[subsys_id].mutex);
56 EXPORT_SYMBOL_GPL(nfnl_lock);
58 void nfnl_unlock(__u8 subsys_id)
60 mutex_unlock(&table[subsys_id].mutex);
62 EXPORT_SYMBOL_GPL(nfnl_unlock);
64 int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n)
66 nfnl_lock(n->subsys_id);
67 if (table[n->subsys_id].subsys) {
68 nfnl_unlock(n->subsys_id);
71 rcu_assign_pointer(table[n->subsys_id].subsys, n);
72 nfnl_unlock(n->subsys_id);
76 EXPORT_SYMBOL_GPL(nfnetlink_subsys_register);
78 int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n)
80 nfnl_lock(n->subsys_id);
81 table[n->subsys_id].subsys = NULL;
82 nfnl_unlock(n->subsys_id);
86 EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister);
88 static inline const struct nfnetlink_subsystem *nfnetlink_get_subsys(u_int16_t type)
90 u_int8_t subsys_id = NFNL_SUBSYS_ID(type);
92 if (subsys_id >= NFNL_SUBSYS_COUNT)
95 return rcu_dereference(table[subsys_id].subsys);
98 static inline const struct nfnl_callback *
99 nfnetlink_find_client(u_int16_t type, const struct nfnetlink_subsystem *ss)
101 u_int8_t cb_id = NFNL_MSG_TYPE(type);
103 if (cb_id >= ss->cb_count)
106 return &ss->cb[cb_id];
109 int nfnetlink_has_listeners(struct net *net, unsigned int group)
111 return netlink_has_listeners(net->nfnl, group);
113 EXPORT_SYMBOL_GPL(nfnetlink_has_listeners);
115 int nfnetlink_send(struct sk_buff *skb, struct net *net, u32 pid,
116 unsigned int group, int echo, gfp_t flags)
118 return nlmsg_notify(net->nfnl, skb, pid, group, echo, flags);
120 EXPORT_SYMBOL_GPL(nfnetlink_send);
122 int nfnetlink_set_err(struct net *net, u32 pid, u32 group, int error)
124 return netlink_set_err(net->nfnl, pid, group, error);
126 EXPORT_SYMBOL_GPL(nfnetlink_set_err);
128 int nfnetlink_unicast(struct sk_buff *skb, struct net *net, u_int32_t pid, int flags)
130 return netlink_unicast(net->nfnl, skb, pid, flags);
132 EXPORT_SYMBOL_GPL(nfnetlink_unicast);
134 /* Process one complete nfnetlink message. */
135 static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
137 struct net *net = sock_net(skb->sk);
138 const struct nfnl_callback *nc;
139 const struct nfnetlink_subsystem *ss;
142 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
145 /* All the messages must at least contain nfgenmsg */
146 if (nlmsg_len(nlh) < sizeof(struct nfgenmsg))
149 type = nlh->nlmsg_type;
152 ss = nfnetlink_get_subsys(type);
154 #ifdef CONFIG_MODULES
156 request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type));
158 ss = nfnetlink_get_subsys(type);
167 nc = nfnetlink_find_client(type, ss);
174 int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
175 u_int8_t cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
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;
179 __u8 subsys_id = NFNL_SUBSYS_ID(type);
181 err = nla_parse(cda, ss->cb[cb_id].attr_count,
182 attr, attrlen, ss->cb[cb_id].policy);
189 err = nc->call_rcu(net->nfnl, skb, nlh,
190 (const struct nlattr **)cda);
194 nfnl_lock(subsys_id);
195 if (rcu_dereference_protected(table[subsys_id].subsys,
196 lockdep_is_held(&table[subsys_id].mutex)) != ss ||
197 nfnetlink_find_client(type, ss) != nc)
200 err = nc->call(net->nfnl, skb, nlh,
201 (const struct nlattr **)cda);
204 nfnl_unlock(subsys_id);
212 static void nfnetlink_rcv(struct sk_buff *skb)
214 netlink_rcv_skb(skb, &nfnetlink_rcv_msg);
217 #ifdef CONFIG_MODULES
218 static void nfnetlink_bind(int group)
220 const struct nfnetlink_subsystem *ss;
221 int type = nfnl_group2type[group];
224 ss = nfnetlink_get_subsys(type);
227 request_module("nfnetlink-subsys-%d", type);
234 static int __net_init nfnetlink_net_init(struct net *net)
237 struct netlink_kernel_cfg cfg = {
238 .groups = NFNLGRP_MAX,
239 .input = nfnetlink_rcv,
240 #ifdef CONFIG_MODULES
241 .bind = nfnetlink_bind,
245 nfnl = netlink_kernel_create(net, NETLINK_NETFILTER, &cfg);
248 net->nfnl_stash = nfnl;
249 rcu_assign_pointer(net->nfnl, nfnl);
253 static void __net_exit nfnetlink_net_exit_batch(struct list_head *net_exit_list)
257 list_for_each_entry(net, net_exit_list, exit_list)
258 RCU_INIT_POINTER(net->nfnl, NULL);
260 list_for_each_entry(net, net_exit_list, exit_list)
261 netlink_kernel_release(net->nfnl_stash);
264 static struct pernet_operations nfnetlink_net_ops = {
265 .init = nfnetlink_net_init,
266 .exit_batch = nfnetlink_net_exit_batch,
269 static int __init nfnetlink_init(void)
273 for (i=0; i<NFNL_SUBSYS_COUNT; i++)
274 mutex_init(&table[i].mutex);
276 pr_info("Netfilter messages via NETLINK v%s.\n", nfversion);
277 return register_pernet_subsys(&nfnetlink_net_ops);
280 static void __exit nfnetlink_exit(void)
282 pr_info("Removing netfilter NETLINK layer.\n");
283 unregister_pernet_subsys(&nfnetlink_net_ops);
285 module_init(nfnetlink_init);
286 module_exit(nfnetlink_exit);