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 <net/netlink.h>
28 #include <linux/init.h>
30 #include <linux/netlink.h>
31 #include <linux/netfilter/nfnetlink.h>
33 MODULE_LICENSE("GPL");
34 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
35 MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NETFILTER);
37 static char __initdata nfversion[] = "0.30";
39 static const struct nfnetlink_subsystem __rcu *subsys_table[NFNL_SUBSYS_COUNT];
40 static DEFINE_MUTEX(nfnl_mutex);
44 mutex_lock(&nfnl_mutex);
46 EXPORT_SYMBOL_GPL(nfnl_lock);
48 void nfnl_unlock(void)
50 mutex_unlock(&nfnl_mutex);
52 EXPORT_SYMBOL_GPL(nfnl_unlock);
54 int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n)
57 if (subsys_table[n->subsys_id]) {
61 rcu_assign_pointer(subsys_table[n->subsys_id], n);
66 EXPORT_SYMBOL_GPL(nfnetlink_subsys_register);
68 int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n)
71 subsys_table[n->subsys_id] = NULL;
76 EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister);
78 static inline const struct nfnetlink_subsystem *nfnetlink_get_subsys(u_int16_t type)
80 u_int8_t subsys_id = NFNL_SUBSYS_ID(type);
82 if (subsys_id >= NFNL_SUBSYS_COUNT)
85 return rcu_dereference(subsys_table[subsys_id]);
88 static inline const struct nfnl_callback *
89 nfnetlink_find_client(u_int16_t type, const struct nfnetlink_subsystem *ss)
91 u_int8_t cb_id = NFNL_MSG_TYPE(type);
93 if (cb_id >= ss->cb_count)
96 return &ss->cb[cb_id];
99 int nfnetlink_has_listeners(struct net *net, unsigned int group)
101 return netlink_has_listeners(net->nfnl, group);
103 EXPORT_SYMBOL_GPL(nfnetlink_has_listeners);
105 int nfnetlink_send(struct sk_buff *skb, struct net *net, u32 pid,
106 unsigned int group, int echo, gfp_t flags)
108 return nlmsg_notify(net->nfnl, skb, pid, group, echo, flags);
110 EXPORT_SYMBOL_GPL(nfnetlink_send);
112 int nfnetlink_set_err(struct net *net, u32 pid, u32 group, int error)
114 return netlink_set_err(net->nfnl, pid, group, error);
116 EXPORT_SYMBOL_GPL(nfnetlink_set_err);
118 int nfnetlink_unicast(struct sk_buff *skb, struct net *net, u_int32_t pid, int flags)
120 return netlink_unicast(net->nfnl, skb, pid, flags);
122 EXPORT_SYMBOL_GPL(nfnetlink_unicast);
124 /* Process one complete nfnetlink message. */
125 static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
127 struct net *net = sock_net(skb->sk);
128 const struct nfnl_callback *nc;
129 const struct nfnetlink_subsystem *ss;
132 if (!capable(CAP_NET_ADMIN))
135 /* All the messages must at least contain nfgenmsg */
136 if (nlh->nlmsg_len < NLMSG_LENGTH(sizeof(struct nfgenmsg)))
139 type = nlh->nlmsg_type;
142 ss = nfnetlink_get_subsys(type);
144 #ifdef CONFIG_MODULES
146 request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type));
148 ss = nfnetlink_get_subsys(type);
157 nc = nfnetlink_find_client(type, ss);
164 int min_len = NLMSG_SPACE(sizeof(struct nfgenmsg));
165 u_int8_t cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
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;
170 err = nla_parse(cda, ss->cb[cb_id].attr_count,
171 attr, attrlen, ss->cb[cb_id].policy);
178 err = nc->call_rcu(net->nfnl, skb, nlh,
179 (const struct nlattr **)cda);
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)
190 err = nc->call(net->nfnl, skb, nlh,
191 (const struct nlattr **)cda);
200 static void nfnetlink_rcv(struct sk_buff *skb)
202 netlink_rcv_skb(skb, &nfnetlink_rcv_msg);
205 static int __net_init nfnetlink_net_init(struct net *net)
209 nfnl = netlink_kernel_create(net, NETLINK_NETFILTER, NFNLGRP_MAX,
210 nfnetlink_rcv, NULL, THIS_MODULE);
213 net->nfnl_stash = nfnl;
214 rcu_assign_pointer(net->nfnl, nfnl);
218 static void __net_exit nfnetlink_net_exit_batch(struct list_head *net_exit_list)
222 list_for_each_entry(net, net_exit_list, exit_list)
223 RCU_INIT_POINTER(net->nfnl, NULL);
225 list_for_each_entry(net, net_exit_list, exit_list)
226 netlink_kernel_release(net->nfnl_stash);
229 static struct pernet_operations nfnetlink_net_ops = {
230 .init = nfnetlink_net_init,
231 .exit_batch = nfnetlink_net_exit_batch,
234 static int __init nfnetlink_init(void)
236 pr_info("Netfilter messages via NETLINK v%s.\n", nfversion);
237 return register_pernet_subsys(&nfnetlink_net_ops);
240 static void __exit nfnetlink_exit(void)
242 pr_info("Removing netfilter NETLINK layer.\n");
243 unregister_pernet_subsys(&nfnetlink_net_ops);
245 module_init(nfnetlink_init);
246 module_exit(nfnetlink_exit);