🎉 Initial version

TPLinkClient/Protocol.go

@@ -0,0 +1,113 @@
+package TPLinkClient
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+)
+
+// Most of the protocol implementation is from:
+// https://github.com/philippechataignon/smrt/blob/master/protocol.py
+
+func doQuery(header *PacketHeader, payload []byte) []byte {
+	header.OpCode = Get
+	header.SequenceID = (header.SequenceID + 1) % 1000
+
+	// Send the query packet
+	packet := assmblePacket(*header, payload)
+	applyKey(&packet)
+	sendPacket(packet)
+
+	// Listen for a response
+	buf := make([]byte, 8000)
+	len := recvPacket(&buf)
+	if len < 1 {
+		return []byte{}
+	}
+	data := make([]byte, len)
+	copy(data, buf)
+	applyKey(&data)
+
+	return data
+}
+
+func assmblePacket(header PacketHeader, payload []byte) []byte {
+	// Packet size is: 32 bytes header + length of the payload + length of the end bytes
+	header.CheckLength = int16(32 + len(payload) + len(PACKET_END))
+
+	// Encode the header
+	var headerBytes bytes.Buffer
+	err := binary.Write(&headerBytes, binary.BigEndian, header)
+	if err != nil {
+		fmt.Println("Failed generating header bytes")
+	}
+
+	// Concatenate header, payload and end bytes
+	return append(headerBytes.Bytes(), append(payload, PACKET_END...)...)
+}
+
+func buildPayload(requestType uint16, data []byte) []byte {
+	var payload = make([]byte, 4)
+	binary.BigEndian.PutUint16(payload[:2], requestType)
+	copy(payload[2:4], data)
+	return payload
+}
+
+func decodeHeader(data []byte) PacketHeader {
+	var header PacketHeader
+	// Decode header bytes to struct
+	buf := bytes.NewBuffer(data)
+	binary.Read(buf, binary.BigEndian, &header)
+	return header
+}
+
+func decodePayload(data []byte) []PayloadItem {
+	// Payload begins at byte 32 (after the header)
+	payload := make([]byte, len(data)-32)
+	copy(payload[:], data[32:])
+
+	results := make([]PayloadItem, 0)
+	for len(payload) > len(PACKET_END) {
+		// Decode TLV encoded datatype and length
+		var dtype uint16
+		var dlen uint16
+		if err := binary.Read(bytes.NewReader(payload[:2]), binary.BigEndian, &dtype); err != nil {
+			fmt.Println("Failed readling payload type")
+			continue
+		}
+		if err := binary.Read(bytes.NewReader(payload[2:4]), binary.BigEndian, &dlen); err != nil {
+			fmt.Println("Failed readling payload length")
+			continue
+		}
+
+		// Get TLV data
+		data := payload[4 : 4+dlen]
+		// Try to decode the datatype
+		payloadType := PayloadType{Id: dtype, Name: "unknown", DataType: "raw"}
+		for _, e := range payloadTypes {
+			if e.Id == dtype {
+				payloadType = e
+			}
+		}
+		// Append to list
+		result := PayloadItem{
+			Type:  payloadType,
+			Value: data,
+		}
+		results = append(results, result)
+		payload = payload[4+dlen:]
+	}
+	return results
+}
+
+func applyKey(data *[]byte) {
+	s := make([]byte, len(KEY))
+	copy(s, KEY)
+	var j byte = 0
+	for k := range *data {
+		i := (k + 1) & 0xFF
+		j = (j + s[i]) & 0xFF
+		s[i], s[j] = s[j], s[i]           // Swap elements in slice
+		(*data)[k] ^= s[(s[i]+s[j])&0xFF] // XOR operation
+	}
+}