| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| |
| package transport |
| |
| import ( |
| "bufio" |
| "encoding/base64" |
| "encoding/binary" |
| "fmt" |
| |
| log "github.com/Sirupsen/logrus" |
| "github.com/joaojeronimo/go-crc16" |
| "github.com/tarm/serial" |
| |
| "mynewt.apache.org/newt/newtmgr/config" |
| "mynewt.apache.org/newt/util" |
| ) |
| |
| type ConnSerial struct { |
| connProfile config.NewtmgrConnProfile |
| currentPacket *Packet |
| |
| scanner *bufio.Scanner |
| serialChannel *serial.Port |
| } |
| |
| func (cs *ConnSerial) Open(cp config.NewtmgrConnProfile) error { |
| var err error |
| |
| c := &serial.Config{ |
| Name: cp.ConnString(), |
| Baud: 115200, |
| } |
| |
| cs.serialChannel, err = serial.OpenPort(c) |
| if err != nil { |
| return util.NewNewtError(err.Error()) |
| } |
| //defer cs.serialChannel.Close() |
| |
| // Most of the reading will be done line by line, use the |
| // bufio.Scanner to do this |
| cs.scanner = bufio.NewScanner(cs.serialChannel) |
| |
| return nil |
| } |
| |
| func (cs *ConnSerial) ReadPacket() (*Packet, error) { |
| scanner := cs.scanner |
| for scanner.Scan() { |
| line := []byte(scanner.Text()) |
| |
| for { |
| if len(line) > 1 && line[0] == '\r' { |
| line = line[1:] |
| } else { |
| break |
| } |
| } |
| if len(line) < 2 || ((line[0] != 4 || line[1] != 20) && |
| (line[0] != 6 || line[1] != 9)) { |
| continue |
| } |
| |
| base64Data := string(line[2:]) |
| |
| data, err := base64.StdEncoding.DecodeString(base64Data) |
| if err != nil { |
| return nil, util.NewNewtError( |
| fmt.Sprintf("Couldn't decode base64 string: %b", |
| base64Data)) |
| } |
| |
| if line[0] == 6 && line[1] == 9 { |
| if len(data) < 2 { |
| continue |
| } |
| |
| pktLen := binary.BigEndian.Uint16(data[0:2]) |
| cs.currentPacket, err = NewPacket(pktLen) |
| if err != nil { |
| return nil, err |
| } |
| data = data[2:] |
| } |
| |
| if cs.currentPacket == nil { |
| continue |
| } |
| |
| full := cs.currentPacket.AddBytes(data) |
| if full { |
| if crc16.Crc16(cs.currentPacket.GetBytes()) != 0 { |
| return nil, util.NewNewtError("CRC error") |
| } |
| |
| /* |
| * Trim away the 2 bytes of CRC |
| */ |
| cs.currentPacket.TrimEnd(2) |
| pkt := cs.currentPacket |
| cs.currentPacket = nil |
| return pkt, nil |
| } |
| } |
| |
| return nil, util.NewNewtError("Scanning incoming data failed") |
| } |
| |
| func (cs *ConnSerial) writeData(bytes []byte) { |
| log.Debugf("Writing %+v to data channel", bytes) |
| cs.serialChannel.Write(bytes) |
| } |
| |
| func (cs *ConnSerial) WritePacket(pkt *Packet) error { |
| data := pkt.GetBytes() |
| |
| pktData := make([]byte, 2) |
| |
| crc := crc16.Crc16(data) |
| binary.BigEndian.PutUint16(pktData, crc) |
| data = append(data, pktData...) |
| |
| dLen := uint16(len(data)) |
| binary.BigEndian.PutUint16(pktData, dLen) |
| pktData = append(pktData, data...) |
| |
| base64Data := make([]byte, base64.StdEncoding.EncodedLen(len(pktData))) |
| |
| base64.StdEncoding.Encode(base64Data, pktData) |
| |
| written := 0 |
| totlen := len(base64Data) |
| |
| for written < totlen { |
| if written == 0 { |
| cs.writeData([]byte{6, 9}) |
| } else { |
| cs.writeData([]byte{4, 20}) |
| } |
| |
| writeLen := util.Min(122, totlen) |
| writeBytes := base64Data[:writeLen] |
| cs.writeData(writeBytes) |
| cs.writeData([]byte{'\n'}) |
| |
| written += writeLen |
| } |
| |
| return nil |
| } |