ovpn: add missing rtnl_link_ops->get_size callback

ovpn_fill_info emits IFLA_OVPN_MODE inside IFLA_INFO_DATA, but
ovpn_link_ops does not provide a get_size callback. Consequently,
rtnetlink's size estimate for ovpn link messages does not include the
nested mode attribute.

Available skb tailroom may hide this mismatch. When the remaining space
is insufficient, however, ovpn_fill_info returns -EMSGSIZE and message
construction fails.

Add the callback and account for IFLA_OVPN_MODE.

Fixes: c2d950c4672a ("ovpn: add basic interface creation/destruction/management routines")
Signed-off-by: Ralf Lici <ralf@mandelbit.com>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>

diff --git a/drivers/net/ovpn/main.c b/drivers/net/ovpn/main.c
index 9993c1dfe471d925616bf68a96ebd02423d0b536..9d9a0ff690d662d6596d610afbe2440fd734e5f1 100644 (file)
--- a/drivers/net/ovpn/main.c
+++ b/drivers/net/ovpn/main.c
@@ -210,6 +210,12 @@ static int ovpn_newlink(struct net_device *dev,
        return register_netdevice(dev);
 }
 
+static size_t ovpn_get_size(const struct net_device *dev)
+{
+       /* IFLA_OVPN_MODE */
+       return nla_total_size(sizeof(u8));
+}
+
 static int ovpn_fill_info(struct sk_buff *skb, const struct net_device *dev)
 {
        struct ovpn_priv *ovpn = netdev_priv(dev);
@@ -228,6 +234,7 @@ static struct rtnl_link_ops ovpn_link_ops = {
        .policy = ovpn_policy,
        .maxtype = IFLA_OVPN_MAX,
        .newlink = ovpn_newlink,
+       .get_size = ovpn_get_size,
        .fill_info = ovpn_fill_info,
 };