more xbee work
This commit is contained in:
saji
parent
67dbb74f77
commit
5d42f8693a
156
cmd/server.go
156
cmd/server.go
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@ -5,9 +5,13 @@ import (
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"net"
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"time"
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"github.com/kschamplin/gotelem/internal/can"
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"github.com/kschamplin/gotelem/internal/gotelem"
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"github.com/kschamplin/gotelem/internal/socketcan"
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"github.com/kschamplin/gotelem/internal/xbee"
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"github.com/tinylib/msgp/msgp"
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"github.com/urfave/cli/v2"
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"go.bug.st/serial"
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)
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const xbeeCategory = "XBee settings"
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@ -25,7 +29,6 @@ var serveCmd = &cli.Command{
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},
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}
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type session struct {
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conn net.Conn
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send chan gotelem.Body
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@ -34,6 +37,11 @@ type session struct {
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}
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func serve() {
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// start the can listener
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go vcanTest()
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fromCanBus := make(chan can.Frame, 1)
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toCanBus := make(chan can.Frame)
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go canHandler(toCanBus, fromCanBus)
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ln, err := net.Listen("tcp", ":8082")
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if err != nil {
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fmt.Printf("Error listening: %v\n", err)
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@ -53,11 +61,6 @@ func handleCon(conn net.Conn) {
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// reader := msgp.NewReader(conn)
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writer := msgp.NewWriter(conn)
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for {
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// data := telemnet.StatusBody{
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// BatteryPct: 1.2,
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// ErrCode: 0,
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// }
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// data.EncodeMsg(writer)
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data := gotelem.StatusBody{
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BatteryPct: 1.2,
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ErrCode: 0,
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@ -67,3 +70,144 @@ func handleCon(conn net.Conn) {
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time.Sleep(1 * time.Second)
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}
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}
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func xbeeSvc(packets <-chan can.Frame, device string, quit <-chan struct{}) {
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// open the session.
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mode := &serial.Mode{
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BaudRate: 115200,
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}
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sess, err := xbee.NewSerialXBee("/dev/ttyUSB1", mode)
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if err != nil {
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fmt.Printf("got error %v", err)
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panic(err)
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}
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receivedData := make(chan gotelem.Data)
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// make a simple reader that goes in the background.
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go func() {
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msgpReader := msgp.NewReader(sess)
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var msgData gotelem.Data
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msgData.DecodeMsg(msgpReader)
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receivedData <- msgData
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}()
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for {
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select {
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case data := <-receivedData:
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fmt.Printf("Got a data %v\n", data)
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case packet := <-packets:
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fmt.Printf("Got a packet, %v\n", packet)
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}
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}
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}
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// this spins up a new can socket on vcan0 and broadcasts a packet every second.
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func vcanTest() {
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sock, _ := socketcan.NewCanSocket("vcan0")
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testFrame := &can.Frame{
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Id: 0x234,
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Kind: can.SFF,
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Data: []byte{0, 1, 2, 3, 4, 5, 6, 7},
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}
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for {
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fmt.Printf("sending test packet\n")
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sock.Send(testFrame)
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time.Sleep(1 * time.Second)
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}
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}
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func canHandler(pktToSend <-chan can.Frame, pktRecv chan<- can.Frame) {
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sock, _ := socketcan.NewCanSocket("vcan0")
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// start a simple dispatcher that just relays can frames.
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r := make(chan can.Frame)
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go func() {
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for {
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pkt, _ := sock.Recv()
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r <- *pkt
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}
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}()
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for {
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select {
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case msg := <-pktToSend:
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sock.Send(&msg)
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case msg := <-r:
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fmt.Printf("got a packet from the can %v\n", msg)
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pktRecv <- msg
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}
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}
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}
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type BrokerRequest struct {
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Source string // the name of the sender
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Msg can.Frame // the message to send
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}
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type BrokerClient struct {
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Name string // the name of the client
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Ch chan can.Frame // the channel to send frames to this client
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}
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type Broker struct {
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subs map[string]chan can.Frame
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publishCh chan BrokerRequest
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subsCh chan BrokerClient
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unsubCh chan BrokerClient
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}
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func NewBroker(bufsize int) *Broker{
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b := &Broker{
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subs: make(map[string]chan can.Frame),
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publishCh: make(chan BrokerRequest, 3),
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subsCh: make(chan BrokerClient, 3),
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unsubCh: make(chan BrokerClient, 3),
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}
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return b
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}
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func (b *Broker) Start() {
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for {
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select {
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case newClient := <-b.subsCh:
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b.subs[newClient.Name] = newClient.Ch
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case req := <-b.publishCh:
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for name, ch := range b.subs {
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if name == req.Source {
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continue // don't send to ourselves.
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}
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// a kinda-inelegant non-blocking push.
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// if we can't do it, we just drop it. this should ideally never happen.
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select {
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case ch <- req.Msg:
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default:
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fmt.Printf("we dropped a packet to dest %s", name)
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}
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}
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case clientToRemove := <-b.unsubCh:
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close(b.subs[clientToRemove.Name])
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delete(b.subs, clientToRemove.Name)
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}
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}
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}
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func (b *Broker) Publish(name string, msg can.Frame) {
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breq := BrokerRequest{
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Source: name,
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Msg: msg,
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}
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b.publishCh <- breq
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}
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func (b *Broker) Subscribe(name string) <-chan can.Frame {
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ch := make(chan can.Frame, 3)
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bc := BrokerClient{
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Name: name,
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Ch: ch,
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}
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b.subsCh <- bc
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return ch
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}
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5
go.mod
5
go.mod
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@ -9,12 +9,17 @@ require (
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require (
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github.com/cpuguy83/go-md2man/v2 v2.0.2 // indirect
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github.com/creack/goselect v0.1.2 // indirect
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github.com/jmoiron/sqlx v1.3.5 // indirect
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github.com/mattn/go-sqlite3 v1.14.16 // indirect
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github.com/philhofer/fwd v1.1.2 // indirect
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github.com/russross/blackfriday/v2 v2.1.0 // indirect
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github.com/tinylib/msgp v1.1.8 // indirect
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github.com/xrash/smetrics v0.0.0-20201216005158-039620a65673 // indirect
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go.bug.st/serial v1.5.0 // indirect
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go.uber.org/atomic v1.10.0 // indirect
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go.uber.org/multierr v1.11.0 // indirect
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go.uber.org/zap v1.24.0 // indirect
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golang.org/x/mod v0.10.0 // indirect
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golang.org/x/tools v0.8.0 // indirect
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)
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10
go.sum
10
go.sum
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@ -1,5 +1,7 @@
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github.com/cpuguy83/go-md2man/v2 v2.0.2 h1:p1EgwI/C7NhT0JmVkwCD2ZBK8j4aeHQX2pMHHBfMQ6w=
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github.com/cpuguy83/go-md2man/v2 v2.0.2/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
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github.com/creack/goselect v0.1.2 h1:2DNy14+JPjRBgPzAd1thbQp4BSIihxcBf0IXhQXDRa0=
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github.com/creack/goselect v0.1.2/go.mod h1:a/NhLweNvqIYMuxcMOuWY516Cimucms3DglDzQP3hKY=
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github.com/go-sql-driver/mysql v1.6.0/go.mod h1:DCzpHaOWr8IXmIStZouvnhqoel9Qv2LBy8hT2VhHyBg=
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github.com/jmoiron/sqlx v1.3.5 h1:vFFPA71p1o5gAeqtEAwLU4dnX2napprKtHr7PYIcN3g=
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github.com/jmoiron/sqlx v1.3.5/go.mod h1:nRVWtLre0KfCLJvgxzCsLVMogSvQ1zNJtpYr2Ccp0mQ=
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@ -18,6 +20,14 @@ github.com/urfave/cli/v2 v2.25.1/go.mod h1:GHupkWPMM0M/sj1a2b4wUrWBPzazNrIjouW6f
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github.com/xrash/smetrics v0.0.0-20201216005158-039620a65673 h1:bAn7/zixMGCfxrRTfdpNzjtPYqr8smhKouy9mxVdGPU=
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github.com/xrash/smetrics v0.0.0-20201216005158-039620a65673/go.mod h1:N3UwUGtsrSj3ccvlPHLoLsHnpR27oXr4ZE984MbSER8=
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github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
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go.bug.st/serial v1.5.0 h1:ThuUkHpOEmCVXxGEfpoExjQCS2WBVV4ZcUKVYInM9T4=
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go.bug.st/serial v1.5.0/go.mod h1:UABfsluHAiaNI+La2iESysd9Vetq7VRdpxvjx7CmmOE=
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go.uber.org/atomic v1.10.0 h1:9qC72Qh0+3MqyJbAn8YU5xVq1frD8bn3JtD2oXtafVQ=
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go.uber.org/atomic v1.10.0/go.mod h1:LUxbIzbOniOlMKjJjyPfpl4v+PKK2cNJn91OQbhoJI0=
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go.uber.org/multierr v1.11.0 h1:blXXJkSxSSfBVBlC76pxqeO+LN3aDfLQo+309xJstO0=
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go.uber.org/multierr v1.11.0/go.mod h1:20+QtiLqy0Nd6FdQB9TLXag12DsQkrbs3htMFfDN80Y=
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go.uber.org/zap v1.24.0 h1:FiJd5l1UOLj0wCgbSE0rwwXHzEdAZS6hiiSnxJN/D60=
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go.uber.org/zap v1.24.0/go.mod h1:2kMP+WWQ8aoFoedH3T2sq6iJ2yDWpHbP0f6MQbS9Gkg=
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golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
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golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
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golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
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@ -22,13 +22,10 @@ import (
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type Frameable interface {
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// returns the API identifier for this frame.
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GetId() byte
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// encodes this frame correctly.
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Bytes() ([]byte, error)
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Bytes() []byte
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}
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// calculateChecksum is a helper function to calculate the 1-byte checksum of a data range.
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// the data range does not include the start delimiter, or the length uint16 (only the frame payload)
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func calculateChecksum(data []byte) byte {
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@ -39,21 +36,20 @@ func calculateChecksum(data []byte) byte {
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return 0xFF - sum
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}
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// WriteFrame takes a frameable and writes it out to the given writer.
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func WriteFrame(w io.Writer, cmd Frameable) (n int, err error) {
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frame_data, err := cmd.Bytes()
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// writeXBeeFrame takes some bytes and wraps it in an XBee frame.
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//
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// An XBee frame has a start delimiter, followed by the length of the payload,
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// then the payload itself, and finally a checksum.
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func writeXBeeFrame(w io.Writer, data []byte) (n int, err error) {
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if err != nil {
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return
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}
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frame := make([]byte, len(frame_data)+4)
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frame := make([]byte, len(data)+4)
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frame[0] = 0x7E
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binary.BigEndian.PutUint16(frame[1:], uint16(len(frame_data)))
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binary.BigEndian.PutUint16(frame[1:], uint16(len(data)))
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copy(frame[3:], frame_data)
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copy(frame[3:], data)
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chk := calculateChecksum(frame_data)
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chk := calculateChecksum(data)
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frame[len(frame)-1] = chk
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return w.Write(frame)
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@ -69,23 +65,23 @@ type XBeeCmd byte
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const (
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// commands sent to the xbee s3b
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ATCmd XBeeCmd = 0x08 // AT Command
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ATCmdQueue XBeeCmd = 0x09 // AT Command - Queue Parameter Value
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TxReq XBeeCmd = 0x10 // TX Request
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TxReqExpl XBeeCmd = 0x11 // Explicit TX Request
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RemoteCmdReq XBeeCmd = 0x17 // Remote Command Request
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ATCmdType XBeeCmd = 0x08 // AT Command
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ATCmdQueueType XBeeCmd = 0x09 // AT Command - Queue Parameter Value
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TxReqType XBeeCmd = 0x10 // TX Request
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TxReqExplType XBeeCmd = 0x11 // Explicit TX Request
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RemoteCmdReqType XBeeCmd = 0x17 // Remote Command Request
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// commands recieved from the xbee
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ATCmdResponse XBeeCmd = 0x88 // AT Command Response
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ModemStatus XBeeCmd = 0x8A // Modem Status
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TxStatus XBeeCmd = 0x8B // Transmit Status
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RouteInfoPkt XBeeCmd = 0x8D // Route information packet
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AddrUpdate XBeeCmd = 0x8E // Aggregate Addressing Update
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RxPkt XBeeCmd = 0x90 // RX Indicator (AO=0)
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RxPktExpl XBeeCmd = 0x91 // Explicit RX Indicator (AO=1)
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IOSample XBeeCmd = 0x92 // Data Sample RX Indicator
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NodeId XBeeCmd = 0x95 // Note Identification Indicator
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RemoteCmdResp XBeeCmd = 0x97 // Remote Command Response
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ATCmdResponseType XBeeCmd = 0x88 // AT Command Response
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ModemStatusType XBeeCmd = 0x8A // Modem Status
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TxStatusType XBeeCmd = 0x8B // Transmit Status
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RouteInfoType XBeeCmd = 0x8D // Route information packet
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AddrUpdateType XBeeCmd = 0x8E // Aggregate Addressing Update
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RxPktType XBeeCmd = 0x90 // RX Indicator (AO=0)
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RxPktExplType XBeeCmd = 0x91 // Explicit RX Indicator (AO=1)
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IOSampleType XBeeCmd = 0x92 // Data Sample RX Indicator
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NodeIdType XBeeCmd = 0x95 // Note Identification Indicator
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RemoteCmdRespType XBeeCmd = 0x97 // Remote Command Response
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)
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// AT commands are hard, so let's write out all the major ones here
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@ -115,42 +111,34 @@ func xbeeFrameSplit(data []byte, atEOF bool) (advance int, token []byte, err err
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return startIdx, nil, nil
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}
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// FIXME: add bounds checking! this can panic.
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var frameLen = binary.BigEndian.Uint16(data[startIdx+1:startIdx+3]) + 4
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if len(data[startIdx:]) < int(frameLen) {
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var frameLen = int(binary.BigEndian.Uint16(data[startIdx+1:startIdx+3])) + 4
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if len(data[startIdx:]) < frameLen {
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// we got the length, but there's not enough data for the frame. we can trim the
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// data that came before the start, but not return a token.
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return startIdx, nil, nil
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}
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// there is enough data to pull a frame.
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// todo: check checksum here? we can return an error.
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return startIdx + int(frameLen), data[startIdx : startIdx+int(frameLen)], nil
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return startIdx + frameLen, data[startIdx : startIdx+frameLen], nil
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}
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// we didn't find a start character in our data, so request more. trash everythign given to us
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return len(data), nil, nil
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}
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func parseFrame(frame []byte) ([]byte, error) {
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if frame[0] != 0x7E {
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return nil, errors.New("incorrect start delimiter")
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}
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fsize := len(frame)
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if calculateChecksum(frame[3:fsize - 1]) != frame[fsize] {
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if calculateChecksum(frame[3:fsize-1]) != frame[fsize] {
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return nil, errors.New("checksum mismatch")
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}
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return frame[3:fsize - 1], nil
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return frame[3 : fsize-1], nil
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}
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// stackup
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// low level readwriter (serial or IP socket)
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// XBee library layer (frame encoding/decoding to/from structs)
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// xbee conn-like layer (ReadWriter + custom control functions)
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// application marshalling format (msgpack or json or gob)
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// application
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|
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|
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type XBeeConn interface {
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io.ReadWriter
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WriteFrame(Frameable, bool) Frameable
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}
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|
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|
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@ -1,7 +1,6 @@
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package xbee
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|
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import (
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"bytes"
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"reflect"
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"testing"
|
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)
|
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|
|
@ -107,32 +106,35 @@ func Test_xbeeFrameSplit(t *testing.T) {
|
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}
|
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}
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|
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func TestWriteFrame(t *testing.T) {
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func Test_parseFrame(t *testing.T) {
|
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type args struct {
|
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cmd Frameable
|
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frame []byte
|
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}
|
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tests := []struct {
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name string
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args args
|
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wantN int
|
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wantW string
|
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want []byte
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wantErr bool
|
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}{
|
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// TODO: Add test cases.
|
||||
{
|
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name: "missing start delimiter",
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args: args{
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frame: []byte{0x00, 0x02, 0x03, 0x00, 0x3},
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},
|
||||
want: nil,
|
||||
wantErr: true,
|
||||
},
|
||||
}
|
||||
for _, tt := range tests {
|
||||
t.Run(tt.name, func(t *testing.T) {
|
||||
w := &bytes.Buffer{}
|
||||
gotN, err := WriteFrame(w, tt.args.cmd)
|
||||
got, err := parseFrame(tt.args.frame)
|
||||
if (err != nil) != tt.wantErr {
|
||||
t.Errorf("WriteFrame() error = %v, wantErr %v", err, tt.wantErr)
|
||||
t.Errorf("parseFrame() error = %v, wantErr %v", err, tt.wantErr)
|
||||
return
|
||||
}
|
||||
if gotN != tt.wantN {
|
||||
t.Errorf("WriteFrame() = %v, want %v", gotN, tt.wantN)
|
||||
}
|
||||
if gotW := w.String(); gotW != tt.wantW {
|
||||
t.Errorf("WriteFrame() = %v, want %v", gotW, tt.wantW)
|
||||
if !reflect.DeepEqual(got, tt.want) {
|
||||
t.Errorf("parseFrame() = %v, want %v", got, tt.want)
|
||||
}
|
||||
})
|
||||
}
|
||||
|
|
|
|||
|
|
@ -2,72 +2,137 @@ package xbee
|
|||
|
||||
import (
|
||||
"bytes"
|
||||
"fmt"
|
||||
"encoding/binary"
|
||||
"fmt"
|
||||
)
|
||||
|
||||
// this file contains some AT command constants and
|
||||
type ATCmdFrame struct {
|
||||
Id byte
|
||||
Cmd string
|
||||
Param []byte
|
||||
Queued bool
|
||||
// This code is handled slightly differently. Rather than use structs to represent
|
||||
// the frame data, we instead use an interface that represents an AT command, and
|
||||
// standalone functions that convert the AT command to frame data.
|
||||
// this way, we can add command support without needing to compose structs.
|
||||
// The downside is that it's more difficult to deal with.
|
||||
//
|
||||
// AT command responses are handled with a struct to get the response status code.
|
||||
//
|
||||
|
||||
// an ATCmd is anything that has a Payload function that returns the given payload
|
||||
// pre-formatted to be send over the wire, and a Cmd command that returns the 2-character
|
||||
// ATcommand itself. It must also have a parse response function that takes the response struct.
|
||||
type ATCmd interface {
|
||||
Payload() []byte // converts the AT command options to the binary argument format
|
||||
Cmd() [2]rune // returns the AT command string.
|
||||
Parse(*ATCmdResponse) error // takes a command response and parses the data into itself.
|
||||
}
|
||||
|
||||
// implement the frame stuff for us.
|
||||
func (atFrame *ATCmdFrame) Bytes() ([]byte, error) {
|
||||
// The AT command, in its raw format. we don't handle parameters since it's dealt with by
|
||||
// the interface.
|
||||
type RawATCmd []byte
|
||||
|
||||
// implements frameable. this is kinda stupid but makes it more safe.
|
||||
func (b RawATCmd) Bytes() []byte {
|
||||
return b
|
||||
}
|
||||
|
||||
// EncodeATCommand takes an AT command and encodes it in the payload format.
|
||||
// it takes the frame index (which can be zero) as well as if it should be queued or
|
||||
// not. It encodes the AT command to be framed and sent over the wire and returns the packet
|
||||
func encodeATCommand(at ATCmd, idx uint8, queued bool) RawATCmd {
|
||||
// we encode a new byte slice that contains the cmd + payload concatenated correclty.
|
||||
// this is then used to make the command frame, which contains ID/Type/Queued or not.
|
||||
// the ATCmdFrame can be converted to bytes to be sent over the wire once framed.
|
||||
|
||||
buf := new(bytes.Buffer)
|
||||
|
||||
if atFrame.Queued {
|
||||
// queued (batched) at comamnds have different Frame type
|
||||
buf.WriteByte(byte(ATCmdQueue))
|
||||
|
||||
// we change the frame type based on if it's queued.
|
||||
if queued {
|
||||
buf.WriteByte(byte(ATCmdQueueType))
|
||||
} else {
|
||||
// normal frame type
|
||||
buf.WriteByte(byte(ATCmd))
|
||||
|
||||
buf.WriteByte(byte(ATCmdType))
|
||||
}
|
||||
|
||||
buf.WriteByte(atFrame.Id)
|
||||
// next is the provided frame identifier, used for callbacks.
|
||||
buf.WriteByte(idx)
|
||||
|
||||
// write cmd, if it's the right length.
|
||||
if cmdLen := len(atFrame.Cmd); cmdLen != 2 {
|
||||
return nil, fmt.Errorf("AT command incorrect length: %d", cmdLen)
|
||||
}
|
||||
buf.Write([]byte(atFrame.Cmd))
|
||||
cmd := at.Cmd()
|
||||
buf.WriteByte(byte(cmd[0]))
|
||||
buf.WriteByte(byte(cmd[1]))
|
||||
// the payload can be empty. This would make it a query.
|
||||
p := at.Payload()
|
||||
buf.Write(p)
|
||||
|
||||
// write param.
|
||||
buf.Write(atFrame.Param)
|
||||
return buf.Bytes(), nil
|
||||
return buf.Bytes()
|
||||
}
|
||||
|
||||
type ATCmdResponse struct {
|
||||
Cmd string
|
||||
Status ATCmdStatus
|
||||
Data []byte
|
||||
}
|
||||
|
||||
func ParseATCmdResponse(p []byte) (*ATCmdResponse, error) {
|
||||
|
||||
if p[0] != 0x88 {
|
||||
return nil, fmt.Errorf("invalid frame type 0x%x", p[0])
|
||||
}
|
||||
resp := &ATCmdResponse{
|
||||
Cmd: string(p[2:4]),
|
||||
Status: ATCmdStatus(p[4]),
|
||||
// TODO: check if this overflows when there's no payload.
|
||||
Data: p[5:],
|
||||
}
|
||||
|
||||
return resp, nil
|
||||
}
|
||||
|
||||
//go:generate stringer -output=at_cmd_status.go -type ATCmdStatus
|
||||
type ATCmdStatus uint8
|
||||
|
||||
const (
|
||||
ATCmdStatusOK ATCmdStatus = 0
|
||||
ATCmdStatusErr ATCmdStatus = 1
|
||||
|
||||
ATCmdStatusInvalidCmd ATCmdStatus = 2
|
||||
ATCmdStatusInvalidParam ATCmdStatus = 3
|
||||
)
|
||||
|
||||
type RemoteATCmdReq struct {
|
||||
ATCmdFrame
|
||||
Destination uint64
|
||||
Options uint8
|
||||
}
|
||||
|
||||
func (remoteAT *RemoteATCmdReq) Bytes() ([]byte, error) {
|
||||
func encodeRemoteATCommand(at ATCmd, idx uint8, queued bool, destination uint64) RawATCmd {
|
||||
|
||||
// sizing take from
|
||||
buf := new(bytes.Buffer)
|
||||
buf.WriteByte(byte(RemoteCmdReq))
|
||||
|
||||
buf.WriteByte(remoteAT.Id)
|
||||
buf.WriteByte(byte(RemoteCmdReqType))
|
||||
|
||||
a := make([]byte, 8)
|
||||
binary.LittleEndian.PutUint64(a, remoteAT.Destination)
|
||||
buf.Write(a)
|
||||
buf.WriteByte(idx)
|
||||
|
||||
// write the reserved part.
|
||||
buf.Write([]byte{0xFF, 0xFE})
|
||||
// write options
|
||||
buf.WriteByte(remoteAT.Options)
|
||||
binary.Write(buf, binary.BigEndian, destination)
|
||||
|
||||
// now, write the AT command and the data.
|
||||
buf.Write([]byte(remoteAT.Cmd))
|
||||
binary.Write(buf, binary.BigEndian, uint16(0xFFFE))
|
||||
|
||||
buf.Write(remoteAT.Param)
|
||||
// set remote command options. if idx = 0, we set bit zero (disable ack)
|
||||
// if queued is true, we clear bit one (if false we set it)
|
||||
|
||||
return buf.Bytes(), nil
|
||||
var options uint8 = 0
|
||||
if idx == 0 {
|
||||
options = options | 0x1
|
||||
}
|
||||
if !queued {
|
||||
options = options | 0x2
|
||||
}
|
||||
|
||||
// write AT command
|
||||
cmd := at.Cmd()
|
||||
buf.WriteByte(byte(cmd[0]))
|
||||
buf.WriteByte(byte(cmd[1]))
|
||||
|
||||
// write payload.
|
||||
buf.Write(at.Payload())
|
||||
|
||||
return buf.Bytes()
|
||||
}
|
||||
|
||||
// let's actually define some AT commands now.
|
||||
|
|
|
|||
|
|
@ -1,50 +1,60 @@
|
|||
package xbee
|
||||
|
||||
import (
|
||||
"sync"
|
||||
"errors"
|
||||
"sync"
|
||||
)
|
||||
|
||||
// A connTrack is a simple frame mark utility for xbee packets. The xbee api frame
|
||||
// takes a mark that is used when sending the response - this allows to coordinate
|
||||
// the sent packet and the response, since there may be other packets emitted
|
||||
// between them.
|
||||
// between them. The data that is stored in the tag is a channel that contains an error - this
|
||||
// is sent by the reader.
|
||||
type connTrack struct {
|
||||
mu sync.RWMutex // use RW mutex to allow for multiple readers
|
||||
internal map[uint8]bool // map frame tag to if it's been used.
|
||||
mu sync.RWMutex // use RW mutex to allow for multiple readers
|
||||
internal map[uint8]chan []byte
|
||||
// the map is set when writing a frame, and deleted when recieving a matching frame.
|
||||
}
|
||||
|
||||
// GetMark finds the next available marker and takes it, returning the value of
|
||||
// the mark. If no mark can be acquired, it returns an error.
|
||||
func (ct *connTrack) GetMark() (uint8, error) {
|
||||
// the mark as well as a channel to use as a semaphore when the mark is cleared.
|
||||
// If no mark can be acquired, it returns an error.
|
||||
func (ct *connTrack) GetMark() (uint8, <-chan []byte, error) {
|
||||
// get a read lock.
|
||||
ct.mu.RLock()
|
||||
|
||||
// NOTE: we start at one. This is because 0 will not return a frame ever - it's
|
||||
// the "silent mode" mark
|
||||
for i := 1; i < 256; i++ {
|
||||
if !ct.internal[uint8(i)] {
|
||||
if _, ok := ct.internal[uint8(i)]; !ok {
|
||||
// it's free.
|
||||
// discard our read lock and lock for write.
|
||||
ct.mu.RUnlock()
|
||||
|
||||
ct.mu.Lock()
|
||||
// update the value to true.
|
||||
ct.internal[uint8(i)] = true
|
||||
// create the channel, makeit buffered so that we don't
|
||||
// block when we write the error when freeing the mark later.
|
||||
ct.internal[uint8(i)] = make(chan []byte, 1)
|
||||
ct.mu.Unlock()
|
||||
return uint8(i), nil
|
||||
return uint8(i), ct.internal[uint8(i)], nil
|
||||
}
|
||||
}
|
||||
ct.mu.RUnlock()
|
||||
return 0, errors.New("no available marks")
|
||||
return 0, nil, errors.New("no available marks")
|
||||
}
|
||||
|
||||
// ClearMark removes a given mark from the set if it exists, or returns an error.
|
||||
func (ct *connTrack) ClearMark(mark uint8) error {
|
||||
// it takes an error (which can be nil) to send to the channel. this is used to free
|
||||
// whatever command wrote that packet - be it a write() call or a custom AT command that is
|
||||
// tracked.
|
||||
func (ct *connTrack) ClearMark(mark uint8, data []byte) error {
|
||||
ct.mu.RLock()
|
||||
// FIXME: should this be the other way around (swap if and normal execution
|
||||
if ct.internal[mark] {
|
||||
if val, ok := ct.internal[mark]; ok {
|
||||
ct.mu.RUnlock()
|
||||
ct.mu.Lock()
|
||||
val <- data
|
||||
close(val)
|
||||
delete(ct.internal, mark)
|
||||
ct.mu.Unlock()
|
||||
return nil
|
||||
|
|
|
|||
|
|
@ -17,7 +17,7 @@ func ParseRxFrame(data []byte) (*RxFrame, error) {
|
|||
// i.e it excludes start delimiter, length, and checksum.
|
||||
|
||||
// check the frame type (data[0])
|
||||
if data[0] != byte(RxPkt) && data[0] != byte(RxPktExpl) {
|
||||
if data[0] != byte(RxPktType) {
|
||||
return nil, fmt.Errorf("incorrect frame type 0x%x", data[0])
|
||||
}
|
||||
|
||||
|
|
|
|||
|
|
@ -0,0 +1,242 @@
|
|||
package xbee
|
||||
|
||||
import (
|
||||
"bufio"
|
||||
"fmt"
|
||||
"io"
|
||||
"sync"
|
||||
|
||||
"go.bug.st/serial"
|
||||
"go.uber.org/zap"
|
||||
)
|
||||
|
||||
// todo: make transport-agnostic (serial port or TCP/IP)
|
||||
|
||||
// A session is a simple way to manage an xbee device.
|
||||
// it provides io.Reader and io.Writer, as well as some extra functions to handle
|
||||
// custom Xbee frames.
|
||||
type Session interface {
|
||||
io.ReadWriteCloser
|
||||
GetStatus() // todo: figure out signature for this
|
||||
|
||||
// Dial takes an address and allows direct communication with that
|
||||
// device, without using broadcast.
|
||||
Dial(addr uint64) io.ReadWriteCloser
|
||||
// AT command related functions - query, set on local, query, set on remote.
|
||||
|
||||
ATCommand(cmd ATCmd, queued bool) (resp ATCmd, err error)
|
||||
RemoteATCommand(cmd ATCmd, addr uint64) (resp ATCmd, err error)
|
||||
}
|
||||
|
||||
type SerialSession struct {
|
||||
port serial.Port
|
||||
ct connTrack
|
||||
log *zap.SugaredLogger
|
||||
// todo: add queuing structures here for reliable transport and tracking.
|
||||
// this buffer is used for storing data that must be read at some point.
|
||||
rxBuf *bufio.ReadWriter
|
||||
writeLock sync.Mutex // prevents multiple writers from accessing the port at once.
|
||||
}
|
||||
|
||||
func NewSerialXBee(portName string, mode *serial.Mode) (*SerialSession, error) {
|
||||
// make the session with the port/mode given, and set up the conntrack.
|
||||
sess := &SerialSession{}
|
||||
|
||||
port, err := serial.Open(portName, mode)
|
||||
if err != nil {
|
||||
return sess, err
|
||||
}
|
||||
sess.port = port
|
||||
|
||||
sess.ct = connTrack{}
|
||||
|
||||
// setup io readwriter with a pipe.
|
||||
rd, wr := io.Pipe()
|
||||
// this is for reading data *only* - writes are different! it's a
|
||||
// readWriter because the goroutine that runs scan continuously (and handles all other packets)
|
||||
// will write to the buffer when new Rx packets come in, and we can read out from application code.
|
||||
sess.rxBuf = bufio.NewReadWriter(bufio.NewReader(rd), bufio.NewWriter(wr))
|
||||
|
||||
logger, err := zap.NewDevelopment()
|
||||
if err != nil {
|
||||
return sess, err
|
||||
}
|
||||
sess.log = logger.Sugar()
|
||||
|
||||
// start the rx handler in the background. we close it later by closing the serial port.
|
||||
|
||||
go sess.rxHandler()
|
||||
|
||||
return sess, nil
|
||||
}
|
||||
|
||||
// before we can write `Read(p []byte)` we have to have a goroutine that takes the input from
|
||||
// the serial port and parses it out - if it's data, we push the data to a buffer for
|
||||
// the application to read the bytes on its own.
|
||||
//
|
||||
// if it's a different kind of packet, we do custom functionality (free the conntrack, update
|
||||
// local status, etc)
|
||||
func (sess *SerialSession) rxHandler() {
|
||||
// we wrap the serial port read line in a bufio.scanner using our custom split function.
|
||||
scan := bufio.NewScanner(sess.port)
|
||||
scan.Split(xbeeFrameSplit)
|
||||
|
||||
for scan.Scan() {
|
||||
// TODO: check for errors?
|
||||
// data is a frame payload - not a full frame.
|
||||
data, err := parseFrame(scan.Bytes())
|
||||
if err != nil {
|
||||
sess.log.Warnw("error parsing frame", "error", err, "data", data)
|
||||
continue
|
||||
}
|
||||
// data is good, lets parse the frame - using the first byte as the identifier.
|
||||
|
||||
switch XBeeCmd(data[0]) {
|
||||
case RxPktType:
|
||||
// we parse the data, and push it to the rx buffer.
|
||||
//TODO: if we have multiple sources, we need to track them here.
|
||||
frame, err := ParseRxFrame(data)
|
||||
if err != nil {
|
||||
sess.log.Warnw("error parsing rx packet", "error", err, "data", data)
|
||||
break //continue?
|
||||
}
|
||||
// take the data and write it to our internal rx packet buffer.
|
||||
_, err = sess.rxBuf.Write(frame.Payload)
|
||||
if err != nil {
|
||||
sess.log.Warnw("error writing data", "error", err, "payload", frame.Payload)
|
||||
}
|
||||
|
||||
// the "callback"-style handler. Any received packet with a frame ID should
|
||||
// be handled here.
|
||||
case TxStatusType, ATCmdResponseType, RemoteCmdRespType: // these take the frame bytes and parse it themselves.
|
||||
// we hand it back via the channel. we directly find the ID since it's always
|
||||
// the second byte.
|
||||
idx := data[1]
|
||||
|
||||
err := sess.ct.ClearMark(idx, data)
|
||||
if err != nil {
|
||||
// we got a rogue packet lol
|
||||
sess.log.Warnw("rogue frame ID", "id", idx, "error", err)
|
||||
}
|
||||
|
||||
default:
|
||||
// we don't know what to do with it.
|
||||
sess.log.Infow("unhandled packet type", "type", data[0], "id", data[1])
|
||||
|
||||
}
|
||||
|
||||
}
|
||||
// if we get here, the serial port has closed. this is fine, usually.
|
||||
}
|
||||
|
||||
// This implements io.Reader for the UART Session.
|
||||
func (sess *SerialSession) Read(p []byte) (int, error) {
|
||||
// Since we have an rx buffer, we just read from that and return the results.
|
||||
return sess.rxBuf.Read(p)
|
||||
}
|
||||
|
||||
func (sess *SerialSession) Write(p []byte) (n int, err error) {
|
||||
// we construct a packet - using the conntrack to ensure that the packet is okay.
|
||||
// we block - this is more correct.
|
||||
idx, ch, err := sess.ct.GetMark()
|
||||
if err != nil {
|
||||
return
|
||||
}
|
||||
wf := &TxFrame{
|
||||
Id: idx,
|
||||
Destination: BroadcastAddr,
|
||||
Payload: p,
|
||||
}
|
||||
// write the actual packet
|
||||
|
||||
sess.writeLock.Lock()
|
||||
n, err = writeXBeeFrame(sess.port, wf.Bytes())
|
||||
if err != nil {
|
||||
return
|
||||
}
|
||||
sess.writeLock.Unlock()
|
||||
|
||||
// finally, wait for the channel we got to return. this means that
|
||||
// the matching response frame was received, so we can parse it.
|
||||
// TODO: add timeout.
|
||||
responseFrame := <-ch
|
||||
|
||||
// this is a tx status frame bytes, so lets parse it out.
|
||||
status, err := ParseTxStatusFrame(responseFrame)
|
||||
if err != nil {
|
||||
return
|
||||
}
|
||||
|
||||
if status.Status != 0 {
|
||||
err = fmt.Errorf("tx failed 0x%x", status.Status)
|
||||
}
|
||||
|
||||
return
|
||||
}
|
||||
|
||||
// sends a local AT command. If `queued` is true, the command is not immediately applied;
|
||||
// instead, an AC command must be set to apply the queued changes. `queued` does not
|
||||
// affect query-type commands, which always return right away.
|
||||
// the AT command is an interface.
|
||||
func (sess *SerialSession) ATCommand(at ATCmd, queued bool) error {
|
||||
// we must encode the command, and then create the actual packet.
|
||||
// then we send the packet, and wait for the response
|
||||
// TODO: how to handle multiple-response-packet AT commands?
|
||||
// (mainly Node Discovery ND)
|
||||
|
||||
// get a mark for the frame
|
||||
|
||||
isQuery := len(at.Payload()) > 0
|
||||
idx, ch, err := sess.ct.GetMark()
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
rawData := encodeATCommand(at, idx, queued)
|
||||
|
||||
sess.writeLock.Lock()
|
||||
_, err = writeXBeeFrame(sess.port, rawData)
|
||||
sess.writeLock.Unlock()
|
||||
|
||||
if err != nil {
|
||||
return fmt.Errorf("error writing xbee frame: %w", err)
|
||||
}
|
||||
|
||||
// we use the AT command that was provided to decode the frame.
|
||||
// Parse stores the response result locally.
|
||||
// we parse the base frame ourselves, and if it's okay we pass it
|
||||
// to the provided ATCommand
|
||||
|
||||
// TODO: add timeout.
|
||||
resp, err := ParseATCmdResponse(<-ch)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
if resp.Status != 0 {
|
||||
// sinec ATCmdStatus is a stringer thanks to the generator
|
||||
return fmt.Errorf("AT command failed: %s", resp.Status)
|
||||
}
|
||||
|
||||
// finally, we use the provided ATCmd interface to unpack the data.
|
||||
// this overwrites the values provided, but this should only happen
|
||||
// during a query, so this is fine.
|
||||
// TODO: skip if not a query command?
|
||||
|
||||
if isQuery {
|
||||
return at.Parse(resp)
|
||||
}
|
||||
|
||||
// it's not a query, and there was no error, so we just plain return
|
||||
return nil
|
||||
|
||||
}
|
||||
|
||||
// Does this need to exist?
|
||||
func (sess *SerialSession) GetStatus() {
|
||||
panic("TODO: implement")
|
||||
}
|
||||
|
||||
// Implement the io.Closer.
|
||||
func (sess *SerialSession) Close() error {
|
||||
return sess.port.Close()
|
||||
}
|
||||
|
|
@ -3,7 +3,9 @@ package xbee
|
|||
import (
|
||||
"bytes"
|
||||
"encoding/binary"
|
||||
"fmt"
|
||||
)
|
||||
|
||||
// transmissions to this address are instead broadcast
|
||||
const BroadcastAddr = 0xFFFF
|
||||
|
||||
|
|
@ -15,15 +17,15 @@ type TxFrame struct {
|
|||
Payload []byte
|
||||
}
|
||||
|
||||
func (txFrame *TxFrame) Bytes() ([]byte, error) {
|
||||
func (txFrame *TxFrame) Bytes() []byte {
|
||||
buf := new(bytes.Buffer)
|
||||
|
||||
buf.WriteByte(byte(TxReq))
|
||||
buf.WriteByte(byte(TxReqType))
|
||||
|
||||
buf.WriteByte(txFrame.Id)
|
||||
|
||||
a := make([]byte, 8)
|
||||
binary.LittleEndian.PutUint64(a, txFrame.Destination)
|
||||
binary.BigEndian.PutUint64(a, txFrame.Destination)
|
||||
buf.Write(a)
|
||||
|
||||
// write the reserved part.
|
||||
|
|
@ -36,5 +38,39 @@ func (txFrame *TxFrame) Bytes() ([]byte, error) {
|
|||
|
||||
buf.Write(txFrame.Payload)
|
||||
|
||||
return buf.Bytes(), nil
|
||||
return buf.Bytes()
|
||||
}
|
||||
|
||||
// we also handle transmit status response frames here.
|
||||
// these are emitted by the xbee when the status of the tx packet is known.
|
||||
// it has an Id that matches it to the corressponding transmit request.
|
||||
type TxStatus uint8
|
||||
|
||||
//go:generate stringer -output=txStatus.go -type TxStatus
|
||||
const (
|
||||
TxStatusSuccess TxStatus = 0x00
|
||||
TxStatusNoACK TxStatus = 0x01
|
||||
TxStatusCCAFail TxStatus = 0x02
|
||||
TxStatusIndirect TxStatus = 0x03
|
||||
TxStatusTxFail TxStatus = 0x04
|
||||
TxStatusACKFail TxStatus = 0x21
|
||||
// TODO: finish this
|
||||
)
|
||||
|
||||
type TxStatusFrame struct {
|
||||
Id uint8 // the Frame identifier that this status frame represents.
|
||||
Status TxStatus // the status itself - TxStatus is a stringable.
|
||||
}
|
||||
|
||||
func ParseTxStatusFrame(data []byte) (*TxStatusFrame, error) {
|
||||
if data[0] != byte(TxStatusType) {
|
||||
return nil, fmt.Errorf("incorrect frame type for Tx status frame 0x%x", data[0])
|
||||
}
|
||||
|
||||
status := &TxStatusFrame{
|
||||
Id: data[1],
|
||||
Status: TxStatus(data[2]),
|
||||
}
|
||||
|
||||
return status, nil
|
||||
}
|
||||
|
|
|
|||
Loading…
Reference in a new issue