Allow ethtool to change tun link settings

Let user space set whatever it would like to advertise for the
tun interface.  Preserve the existing defaults.

Signed-off-by: Chas Williams <3chas3@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 25 insertions, 2 deletions

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index c94fffee5ea9..067fc9e7e3ed 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -81,6 +81,9 @@
 #include <linux/uaccess.h>
 #include <linux/proc_fs.h>
 
+static void tun_default_link_ksettings(struct net_device *dev,
+                                       struct ethtool_link_ksettings *cmd);
+
 /* Uncomment to enable debugging */
 /* #define TUN_DEBUG 1 */
 
@@ -242,6 +245,7 @@ struct tun_struct {
         struct bpf_prog __rcu *xdp_prog;
         struct tun_prog __rcu *steering_prog;
         struct tun_prog __rcu *filter_prog;
+        struct ethtool_link_ksettings link_ksettings;
 };
 
 struct veth {
@@ -2295,6 +2299,7 @@ static void tun_setup(struct net_device *dev)
 
         tun->owner = INVALID_UID;
         tun->group = INVALID_GID;
+        tun_default_link_ksettings(dev, &tun->link_ksettings);
 
         dev->ethtool_ops = &tun_ethtool_ops;
         dev->needs_free_netdev = true;
@@ -3326,8 +3331,8 @@ static struct miscdevice tun_miscdev = {
 
 /* ethtool interface */
 
-static int tun_get_link_ksettings(struct net_device *dev,
-                                  struct ethtool_link_ksettings *cmd)
+static void tun_default_link_ksettings(struct net_device *dev,
+                                       struct ethtool_link_ksettings *cmd)
 {
         ethtool_link_ksettings_zero_link_mode(cmd, supported);
         ethtool_link_ksettings_zero_link_mode(cmd, advertising);
@@ -3336,6 +3341,23 @@ static int tun_get_link_ksettings(struct net_device *dev,
         cmd->base.port          = PORT_TP;
         cmd->base.phy_address   = 0;
         cmd->base.autoneg       = AUTONEG_DISABLE;
+}
+
+static int tun_get_link_ksettings(struct net_device *dev,
+                                  struct ethtool_link_ksettings *cmd)
+{
+        struct tun_struct *tun = netdev_priv(dev);
+
+        memcpy(cmd, &tun->link_ksettings, sizeof(*cmd));
+        return 0;
+}
+
+static int tun_set_link_ksettings(struct net_device *dev,
+                                  const struct ethtool_link_ksettings *cmd)
+{
+        struct tun_struct *tun = netdev_priv(dev);
+
+        memcpy(&tun->link_ksettings, cmd, sizeof(*cmd));
         return 0;
 }
 
@@ -3406,6 +3428,7 @@ static const struct ethtool_ops tun_ethtool_ops = {
         .get_coalesce   = tun_get_coalesce,
         .set_coalesce   = tun_set_coalesce,
         .get_link_ksettings = tun_get_link_ksettings,
+        .set_link_ksettings = tun_set_link_ksettings,
 };
 
 static int tun_queue_resize(struct tun_struct *tun)