local proto = Proto("pl2303.bulk", "PL2303 Serial Data")

local ep_dir_f = Field.new("usb.endpoint_address.direction")

proto.fields.data_in = ProtoField.bytes("pl2303.bulk.data_in", "Data In")
proto.fields.data_out = ProtoField.bytes("pl2303.bulk.data_out", "Data Out")

pcall(DissectorTable.heuristic_new, "pl2303.serial_data", proto)

function proto.dissector(buffer, pinfo, tree)
  if buffer:captured_len() < 1 then return end

  local sub = tree:add(proto, buffer())
  pinfo.cols.info:set("PL2303 Serial")

  local ep_dir = ep_dir_f()() -- 0: h2d, 1: d2h
  if ep_dir == 0 then
    pinfo.cols.info:append(" out")
    pinfo.p2p_dir = P2P_DIR_SENT
    sub:add(proto.fields.data_out, buffer())
  else
    pinfo.cols.info:append(" in")
    pinfo.p2p_dir = P2P_DIR_RECV
    sub:add(proto.fields.data_in, buffer())
  end

  DissectorTable.try_heuristics("pl2303.serial_data", buffer, pinfo, tree)
end

function usb_protocol_key(class, subclass, protocol)
  return bit.bor(
    bit.lshift(1, 31),
    bit.lshift(bit.band(class, 0xff), 16),
    bit.lshift(bit.band(subclass, 0xff), 8),
    bit.band(protocol, 0xff)
  )
end

local bulk_table = DissectorTable.get("usb.bulk")
bulk_table:add(usb_protocol_key(0xff, 0x00, 0x00), proto)
bulk_table:add(0xffff, proto)