Merge branch 'MTU-core-range-checking-more'

Jarod Wilson says:

====================
net: use core MTU range checking everywhere

This stack of patches should get absolutely everything in the kernel
converted from doing their own MTU range checking to the core MTU range
checking. This second spin includes alterations to hopefully fix all
concerns raised with the first, as well as including some additional
changes to drivers and infrastructure where I completely missed necessary
updates.

These have all been built through the 0-day build infrastructure via the
(rebasing) master branch at https://github.com/jarodwilson/linux-muck, which
at the time of the most recent compile across 147 configs, was based on
net-next at commit 7b1536ef0aa0.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 34 insertions, 30 deletions

diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index e7d16687538b..c0170b6956bb 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -2367,43 +2367,31 @@ static void vxlan_set_multicast_list(struct net_device *dev)
 {
 }
 
-static int __vxlan_change_mtu(struct net_device *dev,
-			      struct net_device *lowerdev,
-			      struct vxlan_rdst *dst, int new_mtu, bool strict)
+static int vxlan_change_mtu(struct net_device *dev, int new_mtu)
 {
-	int max_mtu = IP_MAX_MTU;
-
-	if (lowerdev)
-		max_mtu = lowerdev->mtu;
+	struct vxlan_dev *vxlan = netdev_priv(dev);
+	struct vxlan_rdst *dst = &vxlan->default_dst;
+	struct net_device *lowerdev = __dev_get_by_index(vxlan->net,
+							 dst->remote_ifindex);
+	bool use_ipv6 = false;
 
 	if (dst->remote_ip.sa.sa_family == AF_INET6)
-		max_mtu -= VXLAN6_HEADROOM;
-	else
-		max_mtu -= VXLAN_HEADROOM;
-
-	if (new_mtu < 68)
-		return -EINVAL;
+		use_ipv6 = true;
 
-	if (new_mtu > max_mtu) {
-		if (strict)
+	/* This check is different than dev->max_mtu, because it looks at
+	 * the lowerdev->mtu, rather than the static dev->max_mtu
+	 */
+	if (lowerdev) {
+		int max_mtu = lowerdev->mtu -
+			      (use_ipv6 ? VXLAN6_HEADROOM : VXLAN_HEADROOM);
+		if (new_mtu > max_mtu)
 			return -EINVAL;
-
-		new_mtu = max_mtu;
 	}
 
 	dev->mtu = new_mtu;
 	return 0;
 }
 
-static int vxlan_change_mtu(struct net_device *dev, int new_mtu)
-{
-	struct vxlan_dev *vxlan = netdev_priv(dev);
-	struct vxlan_rdst *dst = &vxlan->default_dst;
-	struct net_device *lowerdev = __dev_get_by_index(vxlan->net,
-							 dst->remote_ifindex);
-	return __vxlan_change_mtu(dev, lowerdev, dst, new_mtu, true);
-}
-
 static int vxlan_fill_metadata_dst(struct net_device *dev, struct sk_buff *skb)
 {
 	struct vxlan_dev *vxlan = netdev_priv(dev);
@@ -2795,6 +2783,10 @@ static int vxlan_dev_configure(struct net *src_net, struct net_device *dev,
 		vxlan_ether_setup(dev);
 	}
 
+	/* MTU range: 68 - 65535 */
+	dev->min_mtu = ETH_MIN_MTU;
+	dev->max_mtu = ETH_MAX_MTU;
+
 	vxlan->net = src_net;
 
 	dst->remote_vni = conf->vni;
@@ -2838,7 +2830,8 @@ static int vxlan_dev_configure(struct net *src_net, struct net_device *dev,
 #endif
 
 		if (!conf->mtu)
-			dev->mtu = lowerdev->mtu - (use_ipv6 ? VXLAN6_HEADROOM : VXLAN_HEADROOM);
+			dev->mtu = lowerdev->mtu -
+				   (use_ipv6 ? VXLAN6_HEADROOM : VXLAN_HEADROOM);
 
 		needed_headroom = lowerdev->hard_header_len;
 	} else if (vxlan_addr_multicast(&dst->remote_ip)) {
@@ -2847,9 +2840,20 @@ static int vxlan_dev_configure(struct net *src_net, struct net_device *dev,
 	}
 
 	if (conf->mtu) {
-		err = __vxlan_change_mtu(dev, lowerdev, dst, conf->mtu, false);
-		if (err)
-			return err;
+		int max_mtu = ETH_MAX_MTU;
+
+		if (lowerdev)
+			max_mtu = lowerdev->mtu;
+
+		max_mtu -= (use_ipv6 ? VXLAN6_HEADROOM : VXLAN_HEADROOM);
+
+		if (conf->mtu < dev->min_mtu || conf->mtu > dev->max_mtu)
+			return -EINVAL;
+
+		dev->mtu = conf->mtu;
+
+		if (conf->mtu > max_mtu)
+			dev->mtu = max_mtu;
 	}
 
 	if (use_ipv6 || conf->flags & VXLAN_F_COLLECT_METADATA)