Add TP-Link HS100 support

1 files changed, 125 insertions, 0 deletions

diff --git a/tplink.go b/tplink.go
new file mode 100644
index 0000000..11d8ab1
--- /dev/null
+++ b/tplink.go
@@ -0,0 +1,125 @@
+package main
+
+import (
+	"context"
+	"encoding/binary"
+	"fmt"
+	"log"
+	"net"
+	"time"
+	"strings"
+)
+
+const (
+	MAX_PAYLOAD = 4294967295 // TP-Link WiFi plug protocol: max. 2^32-1 bytes
+	TPLink_HS100_ON = true
+	TPLink_HS100_OFF = false
+)
+
+func TPLinkRun(config TPLinkConfigs, route Route) {
+	for message := range route.Destination {
+		ip, action, err := tplinkParseMessage(config, message)
+		if err != nil {
+			log.Println(err)
+			continue
+		}
+
+		err = set(*ip, action)
+		if err != nil {
+			log.Printf("Could not send action '%v' to %v: %v", action, ip, err)
+		}
+	}
+}
+
+func tplinkParseMessage(config TPLinkConfigs, m MQTTMessage) (ip *net.IP, action bool, err error) {
+	elements := strings.Split(m.Topic, "/")
+
+	if len(elements) != 3 {
+		return nil, false, fmt.Errorf(
+			"Expected three topic levels but got %d in '%s'.",
+			len(elements), m.Topic,
+		)
+	}
+
+	if elements[0] != "plug" || elements[2] != "action" {
+		return nil, false, fmt.Errorf("Expected plug/<id>/action but got: %s", m.Topic)
+	}
+
+	switch string(m.Payload) {
+	case "on":
+		action = TPLink_HS100_ON
+	case "off":
+		action = TPLink_HS100_OFF
+	default:
+		return nil, false, fmt.Errorf("Invalid payload '%s'.", m.Payload)
+	}
+
+	id := elements[1]
+
+	for _, c := range config {
+		if c.ID == id {
+			ip := net.ParseIP(c.IP)
+			return &ip, action, nil
+		}
+	}
+
+	return nil, false, fmt.Errorf("Got message for unknown plug '%s'", id)
+}
+
+func encrypt(data []byte) ([]byte, error) {
+	if len(data) > MAX_PAYLOAD {
+		return []byte{}, fmt.Errorf("Too many bytes to encrypt (%d > %d)!\n",
+			len(data), MAX_PAYLOAD)
+	}
+	length := uint32(len(data))
+
+	out := make([]byte, 4)
+	binary.BigEndian.PutUint32(out, length)
+
+	key := byte(171)
+	for _, value := range data {
+		key = key ^ value
+		out = append(out, byte(key))
+	}
+
+	return out, nil
+}
+
+func send(address string, data []byte) error {
+	var d net.Dialer
+	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
+	defer cancel()
+
+	conn, err := d.DialContext(ctx, "tcp", address)
+	if err != nil {
+		return fmt.Errorf("Failed to dial: %v", err)
+	}
+	defer conn.Close()
+
+	_, err = conn.Write(data)
+	if err != nil {
+		return fmt.Errorf("Could not write data: %v", err)
+	}
+
+	return nil
+}
+
+func set(ip net.IP, state bool) error {
+	cmd := ""
+
+	switch state {
+		case TPLink_HS100_ON:
+			cmd = `{"system":{"set_relay_state":{"state":1}}}`
+		case TPLink_HS100_OFF:
+			cmd = `{"system":{"set_relay_state":{"state":0}}}`
+	}
+
+	address := fmt.Sprintf("%s:9999", ip.String())
+	data, err := encrypt([]byte(cmd))
+	if err != nil {
+		return err
+	}
+	err = send(address, data)
+
+	return err
+}