summaryrefslogtreecommitdiff
path: root/net/netfilter/nfnetlink.c
diff options
context:
space:
mode:
Diffstat (limited to 'net/netfilter/nfnetlink.c')
-rw-r--r--net/netfilter/nfnetlink.c244
1 files changed, 244 insertions, 0 deletions
diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c
new file mode 100644
index 00000000..e6ddde16
--- /dev/null
+++ b/net/netfilter/nfnetlink.c
@@ -0,0 +1,244 @@
+/* Netfilter messages via netlink socket. Allows for user space
+ * protocol helpers and general trouble making from userspace.
+ *
+ * (C) 2001 by Jay Schulist <jschlst@samba.org>,
+ * (C) 2002-2005 by Harald Welte <laforge@gnumonks.org>
+ * (C) 2005,2007 by Pablo Neira Ayuso <pablo@netfilter.org>
+ *
+ * Initial netfilter messages via netlink development funded and
+ * generally made possible by Network Robots, Inc. (www.networkrobots.com)
+ *
+ * Further development of this code funded by Astaro AG (http://www.astaro.com)
+ *
+ * This software may be used and distributed according to the terms
+ * of the GNU General Public License, incorporated herein by reference.
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/sockios.h>
+#include <linux/net.h>
+#include <linux/skbuff.h>
+#include <asm/uaccess.h>
+#include <net/sock.h>
+#include <net/netlink.h>
+#include <linux/init.h>
+
+#include <linux/netlink.h>
+#include <linux/netfilter/nfnetlink.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
+MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NETFILTER);
+
+static char __initdata nfversion[] = "0.30";
+
+static const struct nfnetlink_subsystem __rcu *subsys_table[NFNL_SUBSYS_COUNT];
+static DEFINE_MUTEX(nfnl_mutex);
+
+void nfnl_lock(void)
+{
+ mutex_lock(&nfnl_mutex);
+}
+EXPORT_SYMBOL_GPL(nfnl_lock);
+
+void nfnl_unlock(void)
+{
+ mutex_unlock(&nfnl_mutex);
+}
+EXPORT_SYMBOL_GPL(nfnl_unlock);
+
+int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n)
+{
+ nfnl_lock();
+ if (subsys_table[n->subsys_id]) {
+ nfnl_unlock();
+ return -EBUSY;
+ }
+ rcu_assign_pointer(subsys_table[n->subsys_id], n);
+ nfnl_unlock();
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(nfnetlink_subsys_register);
+
+int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n)
+{
+ nfnl_lock();
+ subsys_table[n->subsys_id] = NULL;
+ nfnl_unlock();
+ synchronize_rcu();
+ return 0;
+}
+EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister);
+
+static inline const struct nfnetlink_subsystem *nfnetlink_get_subsys(u_int16_t type)
+{
+ u_int8_t subsys_id = NFNL_SUBSYS_ID(type);
+
+ if (subsys_id >= NFNL_SUBSYS_COUNT)
+ return NULL;
+
+ return rcu_dereference(subsys_table[subsys_id]);
+}
+
+static inline const struct nfnl_callback *
+nfnetlink_find_client(u_int16_t type, const struct nfnetlink_subsystem *ss)
+{
+ u_int8_t cb_id = NFNL_MSG_TYPE(type);
+
+ if (cb_id >= ss->cb_count)
+ return NULL;
+
+ return &ss->cb[cb_id];
+}
+
+int nfnetlink_has_listeners(struct net *net, unsigned int group)
+{
+ return netlink_has_listeners(net->nfnl, group);
+}
+EXPORT_SYMBOL_GPL(nfnetlink_has_listeners);
+
+int nfnetlink_send(struct sk_buff *skb, struct net *net, u32 pid,
+ unsigned group, int echo, gfp_t flags)
+{
+ return nlmsg_notify(net->nfnl, skb, pid, group, echo, flags);
+}
+EXPORT_SYMBOL_GPL(nfnetlink_send);
+
+int nfnetlink_set_err(struct net *net, u32 pid, u32 group, int error)
+{
+ return netlink_set_err(net->nfnl, pid, group, error);
+}
+EXPORT_SYMBOL_GPL(nfnetlink_set_err);
+
+int nfnetlink_unicast(struct sk_buff *skb, struct net *net, u_int32_t pid, int flags)
+{
+ return netlink_unicast(net->nfnl, skb, pid, flags);
+}
+EXPORT_SYMBOL_GPL(nfnetlink_unicast);
+
+/* Process one complete nfnetlink message. */
+static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
+{
+ struct net *net = sock_net(skb->sk);
+ const struct nfnl_callback *nc;
+ const struct nfnetlink_subsystem *ss;
+ int type, err;
+
+ if (!capable(CAP_NET_ADMIN))
+ return -EPERM;
+
+ /* All the messages must at least contain nfgenmsg */
+ if (nlh->nlmsg_len < NLMSG_LENGTH(sizeof(struct nfgenmsg)))
+ return 0;
+
+ type = nlh->nlmsg_type;
+replay:
+ rcu_read_lock();
+ ss = nfnetlink_get_subsys(type);
+ if (!ss) {
+#ifdef CONFIG_MODULES
+ rcu_read_unlock();
+ request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type));
+ rcu_read_lock();
+ ss = nfnetlink_get_subsys(type);
+ if (!ss)
+#endif
+ {
+ rcu_read_unlock();
+ return -EINVAL;
+ }
+ }
+
+ nc = nfnetlink_find_client(type, ss);
+ if (!nc) {
+ rcu_read_unlock();
+ return -EINVAL;
+ }
+
+ {
+ int min_len = NLMSG_SPACE(sizeof(struct nfgenmsg));
+ u_int8_t cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
+ struct nlattr *cda[ss->cb[cb_id].attr_count + 1];
+ struct nlattr *attr = (void *)nlh + min_len;
+ int attrlen = nlh->nlmsg_len - min_len;
+
+ err = nla_parse(cda, ss->cb[cb_id].attr_count,
+ attr, attrlen, ss->cb[cb_id].policy);
+ if (err < 0)
+ return err;
+
+ if (nc->call_rcu) {
+ err = nc->call_rcu(net->nfnl, skb, nlh,
+ (const struct nlattr **)cda);
+ rcu_read_unlock();
+ } else {
+ rcu_read_unlock();
+ nfnl_lock();
+ if (rcu_dereference_protected(
+ subsys_table[NFNL_SUBSYS_ID(type)],
+ lockdep_is_held(&nfnl_mutex)) != ss ||
+ nfnetlink_find_client(type, ss) != nc)
+ err = -EAGAIN;
+ else
+ err = nc->call(net->nfnl, skb, nlh,
+ (const struct nlattr **)cda);
+ nfnl_unlock();
+ }
+ if (err == -EAGAIN)
+ goto replay;
+ return err;
+ }
+}
+
+static void nfnetlink_rcv(struct sk_buff *skb)
+{
+ netlink_rcv_skb(skb, &nfnetlink_rcv_msg);
+}
+
+static int __net_init nfnetlink_net_init(struct net *net)
+{
+ struct sock *nfnl;
+
+ nfnl = netlink_kernel_create(net, NETLINK_NETFILTER, NFNLGRP_MAX,
+ nfnetlink_rcv, NULL, THIS_MODULE);
+ if (!nfnl)
+ return -ENOMEM;
+ net->nfnl_stash = nfnl;
+ rcu_assign_pointer(net->nfnl, nfnl);
+ return 0;
+}
+
+static void __net_exit nfnetlink_net_exit_batch(struct list_head *net_exit_list)
+{
+ struct net *net;
+
+ list_for_each_entry(net, net_exit_list, exit_list)
+ RCU_INIT_POINTER(net->nfnl, NULL);
+ synchronize_net();
+ list_for_each_entry(net, net_exit_list, exit_list)
+ netlink_kernel_release(net->nfnl_stash);
+}
+
+static struct pernet_operations nfnetlink_net_ops = {
+ .init = nfnetlink_net_init,
+ .exit_batch = nfnetlink_net_exit_batch,
+};
+
+static int __init nfnetlink_init(void)
+{
+ pr_info("Netfilter messages via NETLINK v%s.\n", nfversion);
+ return register_pernet_subsys(&nfnetlink_net_ops);
+}
+
+static void __exit nfnetlink_exit(void)
+{
+ pr_info("Removing netfilter NETLINK layer.\n");
+ unregister_pernet_subsys(&nfnetlink_net_ops);
+}
+module_init(nfnetlink_init);
+module_exit(nfnetlink_exit);