From d62f9ed4a490309bd9e5df0b42ba5d096e7b5902 Mon Sep 17 00:00:00 2001
From: Patrick McHardy <kaber@trash.net>
Date: Wed, 29 Nov 2006 02:35:17 +0100
Subject: [NETFILTER]: nf_conntrack: automatic sysctl registation for conntrack
 protocols

Add helper functions for sysctl registration with optional instantiating
of common path elements (like net/netfilter) and use it for support for
automatic registation of conntrack protocol sysctls.

Signed-off-by: Patrick McHardy <kaber@trash.net>
---
 net/netfilter/nf_sysctl.c | 134 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 134 insertions(+)
 create mode 100644 net/netfilter/nf_sysctl.c

(limited to 'net/netfilter/nf_sysctl.c')

diff --git a/net/netfilter/nf_sysctl.c b/net/netfilter/nf_sysctl.c
new file mode 100644
index 000000000000..06ddddb2911f
--- /dev/null
+++ b/net/netfilter/nf_sysctl.c
@@ -0,0 +1,134 @@
+/* nf_sysctl.c	netfilter sysctl registration/unregistation
+ *
+ * Copyright (c) 2006 Patrick McHardy <kaber@trash.net>
+ */
+#include <linux/module.h>
+#include <linux/sysctl.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+
+static void
+path_free(struct ctl_table *path, struct ctl_table *table)
+{
+	struct ctl_table *t, *next;
+
+	for (t = path; t != NULL && t != table; t = next) {
+		next = t->child;
+		kfree(t);
+	}
+}
+
+static struct ctl_table *
+path_dup(struct ctl_table *path, struct ctl_table *table)
+{
+	struct ctl_table *t, *last = NULL, *tmp;
+
+	for (t = path; t != NULL; t = t->child) {
+		/* twice the size since path elements are terminated by an
+		 * empty element */
+		tmp = kmemdup(t, 2 * sizeof(*t), GFP_KERNEL);
+		if (tmp == NULL) {
+			if (last != NULL)
+				path_free(path, table);
+			return NULL;
+		}
+
+		if (last != NULL)
+			last->child = tmp;
+		else
+			path = tmp;
+		last = tmp;
+	}
+
+	if (last != NULL)
+		last->child = table;
+	else
+		path = table;
+
+	return path;
+}
+
+struct ctl_table_header *
+nf_register_sysctl_table(struct ctl_table *path, struct ctl_table *table)
+{
+	struct ctl_table_header *header;
+
+	path = path_dup(path, table);
+	if (path == NULL)
+		return NULL;
+	header = register_sysctl_table(path, 0);
+	if (header == NULL)
+		path_free(path, table);
+	return header;
+}
+EXPORT_SYMBOL_GPL(nf_register_sysctl_table);
+
+void
+nf_unregister_sysctl_table(struct ctl_table_header *header,
+			   struct ctl_table *table)
+{
+	struct ctl_table *path = header->ctl_table;
+
+	unregister_sysctl_table(header);
+	path_free(path, table);
+}
+EXPORT_SYMBOL_GPL(nf_unregister_sysctl_table);
+
+/* net/netfilter */
+static struct ctl_table nf_net_netfilter_table[] = {
+	{
+		.ctl_name	= NET_NETFILTER,
+		.procname	= "netfilter",
+		.mode		= 0555,
+	},
+	{
+		.ctl_name	= 0
+	}
+};
+struct ctl_table nf_net_netfilter_sysctl_path[] = {
+	{
+		.ctl_name	= CTL_NET,
+		.procname	= "net",
+		.mode		= 0555,
+		.child		= nf_net_netfilter_table,
+	},
+	{
+		.ctl_name	= 0
+	}
+};
+EXPORT_SYMBOL_GPL(nf_net_netfilter_sysctl_path);
+
+/* net/ipv4/netfilter */
+static struct ctl_table nf_net_ipv4_netfilter_table[] = {
+	{
+		.ctl_name	= NET_IPV4_NETFILTER,
+		.procname	= "netfilter",
+		.mode		= 0555,
+	},
+	{
+		.ctl_name	= 0
+	}
+};
+static struct ctl_table nf_net_ipv4_table[] = {
+	{
+		.ctl_name	= NET_IPV4,
+		.procname	= "ipv4",
+		.mode		= 0555,
+		.child		= nf_net_ipv4_netfilter_table,
+	},
+	{
+		.ctl_name	= 0
+	}
+};
+struct ctl_table nf_net_ipv4_netfilter_sysctl_path[] = {
+	{
+		.ctl_name	= CTL_NET,
+		.procname	= "net",
+		.mode		= 0555,
+		.child		= nf_net_ipv4_table,
+	},
+	{
+		.ctl_name	= 0
+	}
+};
+EXPORT_SYMBOL_GPL(nf_net_ipv4_netfilter_sysctl_path);
-- 
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