net_sched: sfb: optimize enqueue on full queue
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / net / netfilter / nfnetlink.c
blobc879c1a2370e46829c442095b98a58ce705d78b3
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>
26 #include <asm/system.h>
27 #include <net/sock.h>
28 #include <net/netlink.h>
29 #include <linux/init.h>
31 #include <linux/netlink.h>
32 #include <linux/netfilter/nfnetlink.h>
34 MODULE_LICENSE("GPL");
35 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
36 MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NETFILTER);
38 static char __initdata nfversion[] = "0.30";
40 static const struct nfnetlink_subsystem __rcu *subsys_table[NFNL_SUBSYS_COUNT];
41 static DEFINE_MUTEX(nfnl_mutex);
43 void nfnl_lock(void)
45 mutex_lock(&nfnl_mutex);
47 EXPORT_SYMBOL_GPL(nfnl_lock);
49 void nfnl_unlock(void)
51 mutex_unlock(&nfnl_mutex);
53 EXPORT_SYMBOL_GPL(nfnl_unlock);
55 int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n)
57 nfnl_lock();
58 if (subsys_table[n->subsys_id]) {
59 nfnl_unlock();
60 return -EBUSY;
62 RCU_INIT_POINTER(subsys_table[n->subsys_id], n);
63 nfnl_unlock();
65 return 0;
67 EXPORT_SYMBOL_GPL(nfnetlink_subsys_register);
69 int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n)
71 nfnl_lock();
72 subsys_table[n->subsys_id] = NULL;
73 nfnl_unlock();
74 synchronize_rcu();
75 return 0;
77 EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister);
79 static inline const struct nfnetlink_subsystem *nfnetlink_get_subsys(u_int16_t type)
81 u_int8_t subsys_id = NFNL_SUBSYS_ID(type);
83 if (subsys_id >= NFNL_SUBSYS_COUNT)
84 return NULL;
86 return rcu_dereference(subsys_table[subsys_id]);
89 static inline const struct nfnl_callback *
90 nfnetlink_find_client(u_int16_t type, const struct nfnetlink_subsystem *ss)
92 u_int8_t cb_id = NFNL_MSG_TYPE(type);
94 if (cb_id >= ss->cb_count)
95 return NULL;
97 return &ss->cb[cb_id];
100 int nfnetlink_has_listeners(struct net *net, unsigned int group)
102 return netlink_has_listeners(net->nfnl, group);
104 EXPORT_SYMBOL_GPL(nfnetlink_has_listeners);
106 int nfnetlink_send(struct sk_buff *skb, struct net *net, u32 pid,
107 unsigned group, int echo, gfp_t flags)
109 return nlmsg_notify(net->nfnl, skb, pid, group, echo, flags);
111 EXPORT_SYMBOL_GPL(nfnetlink_send);
113 int nfnetlink_set_err(struct net *net, u32 pid, u32 group, int error)
115 return netlink_set_err(net->nfnl, pid, group, error);
117 EXPORT_SYMBOL_GPL(nfnetlink_set_err);
119 int nfnetlink_unicast(struct sk_buff *skb, struct net *net, u_int32_t pid, int flags)
121 return netlink_unicast(net->nfnl, skb, pid, flags);
123 EXPORT_SYMBOL_GPL(nfnetlink_unicast);
125 /* Process one complete nfnetlink message. */
126 static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
128 struct net *net = sock_net(skb->sk);
129 const struct nfnl_callback *nc;
130 const struct nfnetlink_subsystem *ss;
131 int type, err;
133 if (security_netlink_recv(skb, CAP_NET_ADMIN))
134 return -EPERM;
136 /* All the messages must at least contain nfgenmsg */
137 if (nlh->nlmsg_len < NLMSG_LENGTH(sizeof(struct nfgenmsg)))
138 return 0;
140 type = nlh->nlmsg_type;
141 replay:
142 rcu_read_lock();
143 ss = nfnetlink_get_subsys(type);
144 if (!ss) {
145 #ifdef CONFIG_MODULES
146 rcu_read_unlock();
147 request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type));
148 rcu_read_lock();
149 ss = nfnetlink_get_subsys(type);
150 if (!ss)
151 #endif
153 rcu_read_unlock();
154 return -EINVAL;
158 nc = nfnetlink_find_client(type, ss);
159 if (!nc) {
160 rcu_read_unlock();
161 return -EINVAL;
165 int min_len = NLMSG_SPACE(sizeof(struct nfgenmsg));
166 u_int8_t cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
167 struct nlattr *cda[ss->cb[cb_id].attr_count + 1];
168 struct nlattr *attr = (void *)nlh + min_len;
169 int attrlen = nlh->nlmsg_len - min_len;
171 err = nla_parse(cda, ss->cb[cb_id].attr_count,
172 attr, attrlen, ss->cb[cb_id].policy);
173 if (err < 0)
174 return err;
176 if (nc->call_rcu) {
177 err = nc->call_rcu(net->nfnl, skb, nlh,
178 (const struct nlattr **)cda);
179 rcu_read_unlock();
180 } else {
181 rcu_read_unlock();
182 nfnl_lock();
183 if (rcu_dereference_protected(
184 subsys_table[NFNL_SUBSYS_ID(type)],
185 lockdep_is_held(&nfnl_mutex)) != ss ||
186 nfnetlink_find_client(type, ss) != nc)
187 err = -EAGAIN;
188 else
189 err = nc->call(net->nfnl, skb, nlh,
190 (const struct nlattr **)cda);
191 nfnl_unlock();
193 if (err == -EAGAIN)
194 goto replay;
195 return err;
199 static void nfnetlink_rcv(struct sk_buff *skb)
201 netlink_rcv_skb(skb, &nfnetlink_rcv_msg);
204 static int __net_init nfnetlink_net_init(struct net *net)
206 struct sock *nfnl;
208 nfnl = netlink_kernel_create(net, NETLINK_NETFILTER, NFNLGRP_MAX,
209 nfnetlink_rcv, NULL, THIS_MODULE);
210 if (!nfnl)
211 return -ENOMEM;
212 net->nfnl_stash = nfnl;
213 RCU_INIT_POINTER(net->nfnl, nfnl);
214 return 0;
217 static void __net_exit nfnetlink_net_exit_batch(struct list_head *net_exit_list)
219 struct net *net;
221 list_for_each_entry(net, net_exit_list, exit_list)
222 RCU_INIT_POINTER(net->nfnl, NULL);
223 synchronize_net();
224 list_for_each_entry(net, net_exit_list, exit_list)
225 netlink_kernel_release(net->nfnl_stash);
228 static struct pernet_operations nfnetlink_net_ops = {
229 .init = nfnetlink_net_init,
230 .exit_batch = nfnetlink_net_exit_batch,
233 static int __init nfnetlink_init(void)
235 pr_info("Netfilter messages via NETLINK v%s.\n", nfversion);
236 return register_pernet_subsys(&nfnetlink_net_ops);
239 static void __exit nfnetlink_exit(void)
241 pr_info("Removing netfilter NETLINK layer.\n");
242 unregister_pernet_subsys(&nfnetlink_net_ops);
244 module_init(nfnetlink_init);
245 module_exit(nfnetlink_exit);