1 files changed, 207 insertions, 0 deletions
diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c
new file mode 100644
index 0000000..9c0ba17
--- /dev/null
+++ b/net/netfilter/nfnetlink.c
@@ -0,0 +1,207 @@
+/* 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/major.h>
+#include <linux/timer.h>
+#include <linux/string.h>
+#include <linux/sockios.h>
+#include <linux/net.h>
+#include <linux/fcntl.h>
+#include <linux/skbuff.h>
+#include <asm/uaccess.h>
+#include <asm/system.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 struct sock *nfnl = NULL;
+static const struct nfnetlink_subsystem *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;
+	}
+	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();
+
+	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 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(unsigned int group)
+{
+	return netlink_has_listeners(nfnl, group);
+}
+EXPORT_SYMBOL_GPL(nfnetlink_has_listeners);
+
+int nfnetlink_send(struct sk_buff *skb, u32 pid, unsigned group, int echo)
+{
+	return nlmsg_notify(nfnl, skb, pid, group, echo, gfp_any());
+}
+EXPORT_SYMBOL_GPL(nfnetlink_send);
+
+int nfnetlink_unicast(struct sk_buff *skb, u_int32_t pid, int flags)
+{
+	return netlink_unicast(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)
+{
+	const struct nfnl_callback *nc;
+	const struct nfnetlink_subsystem *ss;
+	int type, err;
+
+	if (security_netlink_recv(skb, CAP_NET_ADMIN))
+		return -EPERM;
+
+	/* All the messages must at least contain nfgenmsg */
+	if (nlh->nlmsg_len < NLMSG_SPACE(sizeof(struct nfgenmsg)))
+		return 0;
+
+	type = nlh->nlmsg_type;
+replay:
+	ss = nfnetlink_get_subsys(type);
+	if (!ss) {
+#ifdef CONFIG_MODULES
+		nfnl_unlock();
+		request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type));
+		nfnl_lock();
+		ss = nfnetlink_get_subsys(type);
+		if (!ss)
+#endif
+			return -EINVAL;
+	}
+
+	nc = nfnetlink_find_client(type, ss);
+	if (!nc)
+		return -EINVAL;
+
+	{
+		int min_len = NLMSG_SPACE(sizeof(struct nfgenmsg));
+		u_int8_t cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
+		u_int16_t attr_count = ss->cb[cb_id].attr_count;
+		struct nlattr *cda[attr_count+1];
+
+		if (likely(nlh->nlmsg_len >= min_len)) {
+			struct nlattr *attr = (void *)nlh + NLMSG_ALIGN(min_len);
+			int attrlen = nlh->nlmsg_len - NLMSG_ALIGN(min_len);
+
+			err = nla_parse(cda, attr_count, attr, attrlen,
+					ss->cb[cb_id].policy);
+			if (err < 0)
+				return err;
+		} else
+			return -EINVAL;
+
+		err = nc->call(nfnl, skb, nlh, cda);
+		if (err == -EAGAIN)
+			goto replay;
+		return err;
+	}
+}
+
+static void nfnetlink_rcv(struct sk_buff *skb)
+{
+	nfnl_lock();
+	netlink_rcv_skb(skb, &nfnetlink_rcv_msg);
+	nfnl_unlock();
+}
+
+static void __exit nfnetlink_exit(void)
+{
+	printk("Removing netfilter NETLINK layer.\n");
+	netlink_kernel_release(nfnl);
+	return;
+}
+
+static int __init nfnetlink_init(void)
+{
+	printk("Netfilter messages via NETLINK v%s.\n", nfversion);
+
+	nfnl = netlink_kernel_create(&init_net, NETLINK_NETFILTER, NFNLGRP_MAX,
+				     nfnetlink_rcv, NULL, THIS_MODULE);
+	if (!nfnl) {
+		printk(KERN_ERR "cannot initialize nfnetlink!\n");
+		return -1;
+	}
+
+	return 0;
+}
+
+module_init(nfnetlink_init);
+module_exit(nfnetlink_exit);