netdevsim: add warnings on unexpected UDP tunnel port errors

We should never see a removal of a port which is not in the table
or adding a port to an occupied entry in the table. To make sure
such errors don't escape the checks in the test script add a
warning/kernel spat.

Error injection will not trigger those, nor should it ever put
us in a bad state.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/netdevsim/udp_tunnels.c

@@ -22,11 +22,13 @@ nsim_udp_tunnel_set_port(struct net_device *dev, unsigned int table,
 		msleep(ns->udp_ports.sleep);
 
 	if (!ret) {
-		if (ns->udp_ports.ports[table][entry])
+		if (ns->udp_ports.ports[table][entry]) {
+			WARN(1, "entry already in use\n");
 			ret = -EBUSY;
-		else
+		} else {
 			ns->udp_ports.ports[table][entry] =
 				be16_to_cpu(ti->port) << 16 | ti->type;
+		}
 	}
 
 	netdev_info(dev, "set [%d, %d] type %d family %d port %d - %d\n",
@@ -50,10 +52,13 @@ nsim_udp_tunnel_unset_port(struct net_device *dev, unsigned int table,
 	if (!ret) {
 		u32 val = be16_to_cpu(ti->port) << 16 | ti->type;
 
-		if (val == ns->udp_ports.ports[table][entry])
+		if (val == ns->udp_ports.ports[table][entry]) {
 			ns->udp_ports.ports[table][entry] = 0;
-		else
+		} else {
+			WARN(1, "entry not installed %x vs %x\n",
+			     val, ns->udp_ports.ports[table][entry]);
 			ret = -ENOENT;
+		}
 	}
 
 	netdev_info(dev, "unset [%d, %d] type %d family %d port %d - %d\n",