code: def ofp_ofctl_field_name_to_ryu(field):
      
      mapped = _OXM_FIELD_OFCTL_ALIASES.get(field)
      if mapped:
          return mapped
      if field.endswith("_dst"):
          mapped = _OXM_FIELD_OFCTL_ALIASES.get(field[:-3] + "src")
          if mapped:
              return mapped[:-3] + "dst"
      return field
docs: Convert an ovs-ofctl field name to ryu equivalent.