+ ip_interface_address_del (lm, if_address_index, addr_fib);
+ }
+ else
+ {
+ if (~0 != if_address_index)
+ {
+ ip_interface_address_t *ia;
+
+ ia = pool_elt_at_index (lm->if_address_pool, if_address_index);
+
+ if (ia->flags & IP_INTERFACE_ADDRESS_FLAG_STALE)
+ {
+ if (ia->sw_if_index == sw_if_index)
+ {
+ /* re-adding an address during the replace action.
+ * consdier this the update. clear the flag and
+ * we're done */
+ ia->flags &= ~IP_INTERFACE_ADDRESS_FLAG_STALE;
+ goto done;
+ }
+ else
+ {
+ /* The prefix is moving from one interface to another.
+ * delete the stale and add the new */
+ ip6_add_del_interface_address (vm,
+ ia->sw_if_index,
+ address, address_length, 1);
+ ia = NULL;
+ error = ip_interface_address_add (lm, sw_if_index,
+ addr_fib, address_length,
+ &if_address_index);
+ }
+ }
+ else
+ {
+ vnm->api_errno = VNET_API_ERROR_DUPLICATE_IF_ADDRESS;
+ error = clib_error_create
+ ("Prefix %U already found on interface %U",
+ lm->format_address_and_length, addr_fib, address_length,
+ format_vnet_sw_if_index_name, vnm, ia->sw_if_index);
+ }
+ }
+ else
+ error = ip_interface_address_add (lm, sw_if_index,
+ addr_fib, address_length,
+ &if_address_index);
+ }
+
+ if (error)
+ goto done;