[INET]: Merge sys.net.ipv4.ip_forward and sys.net.ipv4.conf.all.forwarding

AFAIS these two entries should do the same thing - change the
forwarding state on ipv4_devconf and on all the devices.

I propose to merge the handlers together using ctl paths.

The inet_forward_change() is static after this and I move
it higher to be closer to other "propagation" helpers and
to avoid diff making patches based on { and } matching :)
i.e. - make them easier to read.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/inetdevice.h

@@ -135,7 +135,6 @@ extern struct in_device	*inetdev_by_index(int);
 extern __be32		inet_select_addr(const struct net_device *dev, __be32 dst, int scope);
 extern __be32		inet_confirm_addr(const struct net_device *dev, __be32 dst, __be32 local, int scope);
 extern struct in_ifaddr *inet_ifa_byprefix(struct in_device *in_dev, __be32 prefix, __be32 mask);
-extern void		inet_forward_change(void);
 
 static __inline__ int inet_ifa_match(__be32 addr, struct in_ifaddr *ifa)
 {

net/ipv4/devinet.c

@@ -1263,6 +1263,28 @@ static void devinet_copy_dflt_conf(int i)
 	read_unlock(&dev_base_lock);
 }
 
+static void inet_forward_change(void)
+{
+	struct net_device *dev;
+	int on = IPV4_DEVCONF_ALL(FORWARDING);
+
+	IPV4_DEVCONF_ALL(ACCEPT_REDIRECTS) = !on;
+	IPV4_DEVCONF_DFLT(FORWARDING) = on;
+
+	read_lock(&dev_base_lock);
+	for_each_netdev(&init_net, dev) {
+		struct in_device *in_dev;
+		rcu_read_lock();
+		in_dev = __in_dev_get_rcu(dev);
+		if (in_dev)
+			IN_DEV_CONF_SET(in_dev, FORWARDING, on);
+		rcu_read_unlock();
+	}
+	read_unlock(&dev_base_lock);
+
+	rt_cache_flush(0);
+}
+
 static int devinet_conf_proc(ctl_table *ctl, int write,
 			     struct file* filp, void __user *buffer,
 			     size_t *lenp, loff_t *ppos)
@@ -1332,28 +1354,6 @@ static int devinet_conf_sysctl(ctl_table *table, int __user *name, int nlen,
 	return 1;
 }
 
-void inet_forward_change(void)
-{
-	struct net_device *dev;
-	int on = IPV4_DEVCONF_ALL(FORWARDING);
-
-	IPV4_DEVCONF_ALL(ACCEPT_REDIRECTS) = !on;
-	IPV4_DEVCONF_DFLT(FORWARDING) = on;
-
-	read_lock(&dev_base_lock);
-	for_each_netdev(&init_net, dev) {
-		struct in_device *in_dev;
-		rcu_read_lock();
-		in_dev = __in_dev_get_rcu(dev);
-		if (in_dev)
-			IN_DEV_CONF_SET(in_dev, FORWARDING, on);
-		rcu_read_unlock();
-	}
-	read_unlock(&dev_base_lock);
-
-	rt_cache_flush(0);
-}
-
 static int devinet_sysctl_forward(ctl_table *ctl, int write,
 				  struct file* filp, void __user *buffer,
 				  size_t *lenp, loff_t *ppos)
@@ -1536,6 +1536,27 @@ static void devinet_sysctl_unregister(struct ipv4_devconf *p)
 }
 #endif
 
+static struct ctl_table ctl_forward_entry[] = {
+	{
+		.ctl_name	= NET_IPV4_FORWARD,
+		.procname	= "ip_forward",
+		.data		= &ipv4_devconf.data[
+					NET_IPV4_CONF_FORWARDING - 1],
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= devinet_sysctl_forward,
+		.strategy	= devinet_conf_sysctl,
+		.extra1		= &ipv4_devconf,
+	},
+	{ },
+};
+
+static __initdata struct ctl_path net_ipv4_path[] = {
+	{ .procname = "net", .ctl_name = CTL_NET, },
+	{ .procname = "ipv4", .ctl_name = NET_IPV4, },
+	{ },
+};
+
 void __init devinet_init(void)
 {
 	register_gifconf(PF_INET, inet_gifconf);
@@ -1549,6 +1570,7 @@ void __init devinet_init(void)
 			&ipv4_devconf);
 	__devinet_sysctl_register("default", NET_PROTO_CONF_DEFAULT,
 			&ipv4_devconf_dflt);
+	register_sysctl_paths(net_ipv4_path, ctl_forward_entry);
 #endif
 }
 

net/ipv4/sysctl_net_ipv4.c

@@ -27,62 +27,6 @@ static int tcp_retr1_max = 255;
 static int ip_local_port_range_min[] = { 1, 1 };
 static int ip_local_port_range_max[] = { 65535, 65535 };
 
-static
-int ipv4_sysctl_forward(ctl_table *ctl, int write, struct file * filp,
-			void __user *buffer, size_t *lenp, loff_t *ppos)
-{
-	int val = IPV4_DEVCONF_ALL(FORWARDING);
-	int ret;
-
-	ret = proc_dointvec(ctl, write, filp, buffer, lenp, ppos);
-
-	if (write && IPV4_DEVCONF_ALL(FORWARDING) != val)
-		inet_forward_change();
-
-	return ret;
-}
-
-static int ipv4_sysctl_forward_strategy(ctl_table *table,
-			 int __user *name, int nlen,
-			 void __user *oldval, size_t __user *oldlenp,
-			 void __user *newval, size_t newlen)
-{
-	int *valp = table->data;
-	int new;
-
-	if (!newval || !newlen)
-		return 0;
-
-	if (newlen != sizeof(int))
-		return -EINVAL;
-
-	if (get_user(new, (int __user *)newval))
-		return -EFAULT;
-
-	if (new == *valp)
-		return 0;
-
-	if (oldval && oldlenp) {
-		size_t len;
-
-		if (get_user(len, oldlenp))
-			return -EFAULT;
-
-		if (len) {
-			if (len > table->maxlen)
-				len = table->maxlen;
-			if (copy_to_user(oldval, valp, len))
-				return -EFAULT;
-			if (put_user(len, oldlenp))
-				return -EFAULT;
-		}
-	}
-
-	*valp = new;
-	inet_forward_change();
-	return 1;
-}
-
 extern seqlock_t sysctl_port_range_lock;
 extern int sysctl_local_port_range[2];
 
@@ -281,15 +225,6 @@ static struct ctl_table ipv4_table[] = {
 		.mode		= 0644,
 		.proc_handler	= &proc_dointvec
 	},
-	{
-		.ctl_name	= NET_IPV4_FORWARD,
-		.procname	= "ip_forward",
-		.data		= &IPV4_DEVCONF_ALL(FORWARDING),
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= &ipv4_sysctl_forward,
-		.strategy	= &ipv4_sysctl_forward_strategy
-	},
 	{
 		.ctl_name	= NET_IPV4_DEFAULT_TTL,
 		.procname	= "ip_default_ttl",