[IPV4]: Restore old behaviour of default config values

Previously inet devices were only constructed when addresses are added
(or rarely in ipmr).  Therefore the default config values they get are
the ones at the time of these operations.

Now that we're creating inet devices earlier, this changes the
behaviour of default config values in an incompatible way (see bug
#8519).

This patch creates a compromise by setting the default values at the
same point as before but only for those that have not been explicitly
set by the user since the inet device's creation.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 19 insertions, 15 deletions

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index e197347..354e800 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -147,7 +147,7 @@ void in_dev_finish_destroy(struct in_device *idev)
 	}
 }
 
-struct in_device *inetdev_init(struct net_device *dev)
+static struct in_device *inetdev_init(struct net_device *dev)
 {
 	struct in_device *in_dev;
 
@@ -405,12 +405,10 @@ static int inet_set_ifa(struct net_device *dev, struct in_ifaddr *ifa)
 	ASSERT_RTNL();
 
 	if (!in_dev) {
-		in_dev = inetdev_init(dev);
-		if (!in_dev) {
-			inet_free_ifa(ifa);
-			return -ENOBUFS;
-		}
+		inet_free_ifa(ifa);
+		return -ENOBUFS;
 	}
+	ipv4_devconf_setall(in_dev);
 	if (ifa->ifa_dev != in_dev) {
 		BUG_TRAP(!ifa->ifa_dev);
 		in_dev_hold(in_dev);
@@ -520,13 +518,12 @@ static struct in_ifaddr *rtm_to_ifaddr(struct nlmsghdr *nlh)
 
 	in_dev = __in_dev_get_rtnl(dev);
 	if (in_dev == NULL) {
-		in_dev = inetdev_init(dev);
-		if (in_dev == NULL) {
-			err = -ENOBUFS;
-			goto errout;
-		}
+		err = -ENOBUFS;
+		goto errout;
 	}
 
+	ipv4_devconf_setall(in_dev);
+
 	ifa = inet_alloc_ifa();
 	if (ifa == NULL) {
 		/*
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index d570d3a..d96582a 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -152,9 +152,11 @@ struct net_device *ipmr_new_tunnel(struct vifctl *v)
 			dev->flags |= IFF_MULTICAST;
 
 			in_dev = __in_dev_get_rtnl(dev);
-			if (in_dev == NULL && (in_dev = inetdev_init(dev)) == NULL)
+			if (in_dev == NULL)
 				goto failure;
-			IN_DEV_CONF_SET(in_dev, RP_FILTER, 0);
+
+			ipv4_devconf_setall(in_dev);
+			IPV4_DEVCONF(in_dev->cnf, RP_FILTER) = 0;
 
 			if (dev_open(dev))
 				goto failure;
@@ -218,10 +220,15 @@ static struct net_device *ipmr_reg_vif(void)
 	}
 	dev->iflink = 0;
 
-	if ((in_dev = inetdev_init(dev)) == NULL)
+	rcu_read_lock();
+	if ((in_dev = __in_dev_get_rcu(dev)) == NULL) {
+		rcu_read_unlock();
 		goto failure;
+	}
 
-	IN_DEV_CONF_SET(in_dev, RP_FILTER, 0);
+	ipv4_devconf_setall(in_dev);
+	IPV4_DEVCONF(in_dev->cnf, RP_FILTER) = 0;
+	rcu_read_unlock();
 
 	if (dev_open(dev))
 		goto failure;