+ vnet_sw_interface_t *si = vnet_get_sw_interface (vnm, sw_if_index);
+ if (si->type != VNET_SW_INTERFACE_TYPE_HARDWARE)
+ {
+ rv = VNET_API_ERROR_INVALID_VALUE;
+ goto bad_sw_if_index;
+ }
+
+ vnet_hw_interface_t *hi = vnet_get_hw_interface (vnm, si->hw_if_index);
+ ethernet_interface_t *eif = ethernet_get_interface (em, si->hw_if_index);
+
+ if (!eif)
+ {
+ rv = VNET_API_ERROR_FEATURE_DISABLED;
+ goto bad_sw_if_index;
+ }
+
+ if (mtu < hi->min_supported_packet_bytes)
+ {
+ rv = VNET_API_ERROR_INVALID_VALUE;
+ goto bad_sw_if_index;
+ }
+
+ if (mtu > hi->max_supported_packet_bytes)
+ {
+ rv = VNET_API_ERROR_INVALID_VALUE;
+ goto bad_sw_if_index;
+ }
+
+ vnet_hw_interface_set_mtu (vnm, si->hw_if_index, mtu);