Implement Frames

agwpe.go

@@ -14,13 +14,11 @@ type Config struct {
 type Option func(*Config)
 
 type PacketEngine struct {
-	address  string
-	cfg      Config
-	Ready    bool
-	conn     net.Conn
-	mu       sync.Mutex
-	Messages chan []byte
-	version  string
+	address string
+	cfg     Config
+	Ready   bool
+	conn    net.Conn
+	mu      sync.Mutex
 }
 
 func WithTimeout(d time.Duration) Option {
@@ -29,7 +27,7 @@ func WithTimeout(d time.Duration) Option {
 	}
 }
 
-func NewPacketEngine(address string, opts ...Option) *PacketEngine {
+func NewPacketEngine(address string, opts ...Option) (*PacketEngine, error) {
 	defaultCfg := Config{
 		Timeout: 5 * time.Second,
 	}
@@ -38,14 +36,11 @@ func NewPacketEngine(address string, opts ...Option) *PacketEngine {
 		opt(&defaultCfg)
 	}
 
-	pe := PacketEngine{
-		address:  address,
-		cfg:      defaultCfg,
-		Ready:    false,
-		Messages: make(chan []byte),
-	}
-
-	return &pe
+	return &PacketEngine{
+		address: address,
+		cfg:     defaultCfg,
+		Ready:   false,
+	}, nil
 }
 
 func (pe *PacketEngine) Connect() error {
@@ -55,7 +50,6 @@ func (pe *PacketEngine) Connect() error {
 	}
 	pe.conn = conn
 	fmt.Println("Connected to", pe.address)
-	go pe.receiveLoop()
 
 	return nil
 }
@@ -70,37 +64,3 @@ func (pe *PacketEngine) Disconnect() error {
 
 	return nil
 }
-
-func (pe *PacketEngine) Send(data []byte) error {
-	_, err := pe.conn.Write(data)
-
-	return err
-}
-
-func (pe *PacketEngine) receiveLoop() {
-	defer close(pe.Messages)
-
-	for {
-		buf := make([]byte, 1024)
-		n, err := pe.conn.Read(buf)
-		if err != nil {
-			// FIXME: handle error
-			panic(err)
-		}
-
-		data := buf[:n]
-
-		pe.Messages <- data
-	}
-}
-
-func (pe *PacketEngine) Version() string {
-	if pe.conn == nil {
-		return ""
-	}
-	if pe.version != "" {
-		return pe.version
-	}
-
-	return fmt.Sprintf("%d.%d")
-}

cmd/basic_usage/main.go

@@ -1,38 +0,0 @@
-package main
-
-import (
-	"fmt"
-	"os"
-)
-
-import "git.smith.eu/m/go-agwpe"
-
-func main() {
-	engine := agwpe.NewPacketEngine("172.16.0.4:8000")
-
-	err := engine.Connect()
-	if err != nil {
-		fmt.Printf("Error connecting: %v\n", err)
-	}
-	defer engine.Disconnect()
-
-	version := engine.Version()
-	fmt.Printf("AGWPE version: %s\n", version)
-
-	frame := agwpe.NewVersionFrame()
-	frameData, err := frame.Serialize()
-	if err != nil {
-		fmt.Fprintf(os.Stderr, "Serialization error: %v\n", err)
-	}
-
-	err = engine.Send(frameData)
-	if err != nil {
-		fmt.Println("Error:", err)
-	}
-
-	for msg := range engine.Messages {
-		major_verion := (uint16(msg[37]) << 8) | uint16(msg[36])
-		minor_verion := (uint16(msg[41]) << 8) | uint16(msg[40])
-		fmt.Printf("AGWPE version: %d.%d\n", major_verion, minor_verion)
-	}
-}

frame.go

@@ -2,10 +2,9 @@ package agwpe
 
 import (
 	"encoding/binary"
-	"fmt"
 )
 
-type Header struct {
+type FrameHeader struct {
 	Port      byte
 	Reserved0 [3]byte
 	DataKind  byte
@@ -18,52 +17,19 @@ type Header struct {
 	User      [4]byte
 }
 
-func serializeHeader(h Header) []byte {
-	data := make([]byte, 36)
+func (f *FrameHeader) Serialize() []byte {
+	buf := make([]byte, 36)
 
-	data[0] = h.Port
+	buf[0] = f.Port
 	// Ignore reserved bytes 1 to 3
-	data[4] = h.DataKind
+	buf[4] = f.DataKind
 	// Ignore reserved byte 5
-	data[6] = h.PID
+	buf[6] = f.PID
 	// Ignore reserved byte 7
-	copy(data[8:18], h.CallFrom[:])
-	copy(data[18:28], h.CallTo[:])
-	binary.LittleEndian.PutUint32(data[28:32], h.DataLen)
-	copy(data[32:36], h.User[:])
+	copy(buf[8:18], f.CallFrom[:])
+	copy(buf[18:28], f.CallTo[:])
+	binary.LittleEndian.PutUint32(buf[28:32], f.DataLen)
+	copy(buf[32:36], f.User[:])
 
-	return data
-}
-
-type Frame interface {
-	Header() Header
-}
-
-type VersionFrame struct {
-	header       Header
-	major, minor uint16
-}
-
-func NewVersionFrame() *VersionFrame {
-	return &VersionFrame{
-		header: Header{
-			Port:     0x01,
-			DataKind: 0x52},
-	}
-}
-
-func (f *VersionFrame) Header() Header {
-	return f.header
-}
-
-func (f *VersionFrame) Serialize() ([]byte, error) {
-	data := serializeHeader(f.header)
-
-	return data, nil
-}
-
-func (f *VersionFrame) parseVersion(data []byte) {
-	f.major = (uint16(data[37]) << 8) | uint16(data[36])
-	f.minor = (uint16(data[41]) << 8) | uint16(data[40])
-	fmt.Printf("AGWPE version: %d.%d\n", f.major, f.minor)
+	return buf
 }