*
* @vport: vport from which to retrieve MTU
*
- * Retrieves the MTU of the given device.
- *
- * Must be called with RTNL lock or rcu_read_lock.
+ * Retrieves the MTU of the given device. Returns 0 if @vport does not have an
+ * MTU (as e.g. some tunnels do not). Either RTNL lock or rcu_read_lock must
+ * be held.
*/
int vport_get_mtu(const struct vport *vport)
{
+ if (!vport->ops->get_mtu)
+ return 0;
return vport->ops->get_mtu(vport);
}
* vport-specific attributes to @skb.
*
* Returns 0 if successful, -EMSGSIZE if @skb has insufficient room, or another
- * negative error code if a real error occurred.
+ * negative error code if a real error occurred. If an error occurs, @skb is
+ * left unmodified.
*
* Must be called with RTNL lock or rcu_read_lock.
*/
if (vport->ops->get_options) {
int err = vport->ops->get_options(vport, skb);
- if (err)
+ if (err) {
+ nla_nest_cancel(skb, nla);
return err;
+ }
}
nla_nest_end(skb, nla);
int sent;
mtu = vport_get_mtu(vport);
- if (unlikely(packet_length(skb) > mtu && !skb_is_gso(skb))) {
+ if (mtu && unlikely(packet_length(skb) > mtu && !skb_is_gso(skb))) {
if (net_ratelimit())
pr_warn("%s: dropped over-mtu packet: %d > %d\n",
dp_name(vport->dp), packet_length(skb), mtu);