Implement Frames

frame.go

@@ -0,0 +1,69 @@
+package agwpe
+
+import (
+	"encoding/binary"
+	"fmt"
+)
+
+type Header struct {
+	Port      byte
+	Reserved0 [3]byte
+	DataKind  byte
+	Reserved1 byte
+	PID       byte
+	Reserved2 byte
+	CallFrom  [10]byte
+	CallTo    [10]byte
+	DataLen   uint32
+	User      [4]byte
+}
+
+func serializeHeader(h Header) []byte {
+	data := make([]byte, 36)
+
+	data[0] = h.Port
+	// Ignore reserved bytes 1 to 3
+	data[4] = h.DataKind
+	// Ignore reserved byte 5
+	data[6] = h.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[:])
+
+	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)
+}