WIPing intensifies

plug.go

@@ -1,38 +1,71 @@
-// Package plugctl provides an API for Kasa smart home switches.
+// Package plugctl provides an API for controlling Kasa smart home switches.
 package plugctl
 
 import (
+	"bytes"
+	"encoding/binary"
+	"encoding/json"
+	"fmt"
 	"io"
 	"net"
 )
 
-// Plug provides an API for a single Kasa smart home switch.
+const (
+	reqTurnOn     = `{"system":{"set_relay_state":{"state":1}}}`
+	reqTurnOff    = `{"system":{"set_relay_state":{"state":0}}}`
+	reqGetSysinfo = `{"system":{"get_sysinfo":null}}`
+	reqGetEMeter  = `{"emeter":{"get_realtime":null}}`
+)
+
+// Plug provides an API for a single Kasa smart home plug or switch.
 type Plug struct {
-	Addr net.TCPAddr
+	Addr string
 }
 
-type msg struct {
+func (p *Plug) roundTrip(req string) (*response, error) {
-	System *systemMsg `json:"system,omitempty"`
+	conn, err := net.Dial("tcp", p.Addr)
-	EMeter *eMeterMsg `json:"emeter,omitempty"`
+	if err != nil {
+		return nil, fmt.Errorf("dialing plug: %w", err)
+	}
+	defer conn.Close()
+
+	lp := []byte{0, 0, 0, 0}
+	binary.BigEndian.PutUint32(lp, uint32(len(req)))
+
+	// Start by writing length
+	if _, err := conn.Write(lp); err != nil {
+		return nil, fmt.Errorf("writing length: %w", err)
+	}
+	// Rest of the message is encrypted
+	enc := newEncrypter(conn)
+	if _, err := enc.Write([]byte(req)); err != nil {
+		return nil, fmt.Errorf("writing message: %w", err)
 	}
 
-type eMeterMsg struct {
+	// Read length of response
-	GetRealtime *getRealtimeMsg `json:"get_realtime"`
+	if _, err := io.ReadFull(conn, lp); err != nil {
+		return nil, fmt.Errorf("reading length: %w", err)
+	}
+	rlen := binary.BigEndian.Uint32(lp)
+
+	// Read the encrypted response
+	buf := make([]byte, rlen)
+	if _, err := io.ReadFull(conn, buf); err != nil {
+		return nil, fmt.Errorf("reading response: %w", err)
 	}
 
-type getRealtimeMsg struct{}
+	// Decrypt and parse the response
-
+	var resp *response
-type systemMsg struct {
+	dec := json.NewDecoder(newDecrypter(bytes.NewReader(buf)))
-	GetSysInfo    *getSysInfoMsg    `json:"get_sysinfo"`
+	if err := dec.Decode(&resp); err != nil {
-	SetRelayState *setRelayStateMsg `json:"set_relay_state,omitempty"`
+		return nil, fmt.Errorf("reading message: %w", err)
 	}
 
-type getSysInfoMsg struct{}
+	return resp, nil
-
-type setRelayStateMsg struct {
-	State int `json:"state"`
 }
 
+// Implements TP Link's weaksauce encryption.
+// Do NOT use for actually important secrets.
 type decryptReader struct {
 	r io.Reader
 	c byte
@@ -54,6 +87,8 @@ func (d *decryptReader) Read(b []byte) (int, error) {
 	return n, err
 }
 
+// Implements TP Link's weaksauce encryption.
+// Do NOT use for actually important secrets.
 type encryptWriter struct {
 	w io.Writer
 	c byte
@@ -74,3 +109,84 @@ func (e *encryptWriter) Write(b []byte) (int, error) {
 	}
 	return e.w.Write(eb)
 }
+
+/*
+	"sw_ver": "1.0.3 Build 210506 Rel.105435",
+	"hw_ver": "1.0",
+	"model": "KP105(AU)",
+	"deviceId": "8006CF0E89296D2A5BFBDE11C844BB2B1E2D2B7C",
+	"oemId": "EAB15315847573797920EFE7E9000562",
+	"hwId": "120EF751A1A4F170831E6C1F57D97B38",
+	"rssi": -58,
+	"longitude_i": 1473005,
+	"latitude_i": -428429,
+	"alias": "Car charger",
+	"status": "new",
+	"mic_type": "IOT.SMARTPLUGSWITCH",
+	"feature": "TIM",
+	"mac": "00:5F:67:01:A5:50",
+	"updating": 0,
+	"led_off": 0,
+	"obd_src": "tplink",
+	"relay_state": 0,
+	"on_time": 0,
+	"active_mode": "schedule",
+	"icon_hash": "",
+	"dev_name": "Smart Wi-Fi Plug",
+	"next_action": {
+		"type": -1
+	},
+	"ntc_state": 0,
+	"err_code": 0
+*/
+
+type response struct {
+	System *systemMsg `json:"system,omitempty"`
+	EMeter *eMeterMsg `json:"emeter,omitempty"`
+}
+
+type eMeterMsg struct {
+	GetRealtime *getRealtimeMsg `json:"get_realtime"`
+}
+
+type getRealtimeMsg struct{}
+
+type systemMsg struct {
+	GetSysInfo    *getSysInfoMsg    `json:"get_sysinfo"`
+	SetRelayState *setRelayStateMsg `json:"set_relay_state,omitempty"`
+}
+
+type getSysInfoMsg struct {
+	SWVer      string `json:"sw_ver,omitempty"`      // e.g. "1.0.3 Build 210506 Rel.105435",
+	HWVer      string `json:"hw_ver,omitempty"`      // e.g. "1.0",
+	Model      string `json:"model,omitempty"`       // e.g. "KP105(AU)",
+	DeviceID   string `json:"deviceId,omitempty"`    // e.g. "8006CF0E89296D2A5BFBDE11C844BB2B1E2D2B7C",
+	OEMID      string `json:"oemId,omitempty"`       // e.g. "EAB15315847573797920EFE7E9000562",
+	HWID       string `json:"hwId,omitempty"`        // e.g. "120EF751A1A4F170831E6C1F57D97B38",
+	RSSI       int    `json:"rssi,omitempty"`        // e.g. -58,
+	LongitudeI int    `json:"longitude_i,omitempty"` // e.g. 1473005,
+	LatitudeI  int    `json:"latitude_i,omitempty"`  // e.g. -428429,
+	Alias      string `json:"alias,omitempty"`       // e.g. "Car charger",
+	Status     string `json:"status,omitempty"`      // e.g. "new",
+	MICType    string `json:"mic_type,omitempty"`    // e.g. "IOT.SMARTPLUGSWITCH",
+	Feature    string `json:"feature,omitempty"`     // e.g. "TIM",
+	MAC        string `json:"mac,omitempty"`         // e.g. "00:5F:67:01:A5:50",
+	Updating   int    `json:"updating,omitempty"`    // e.g. 0,
+	LEDOff     int    `json:"led_off,omitempty"`     // e.g. 0,
+	OBDSrc     string `json:"obd_src,omitempty"`     // e.g. "tplink",
+	RelayState int    `json:"relay_state,omitempty"` // e.g. 0,
+	OnTime     int    `json:"on_time,omitempty"`     // e.g. 0,
+	ActiveMode string `json:"active_mode,omitempty"` // e.g. "schedule",
+	IconHash   string `json:"icon_hash,omitempty"`   // e.g. "",
+	DevName    string `json:"dev_name,omitempty"`    // e.g. "Smart Wi-Fi Plug",
+	NextAction struct {
+		Type int `json:"type,omitempty"`
+	} `json:"next_action,omitempty"` // e.g. {"type": -1},
+	NTCState int `json:"ntc_state,omitempty"` // e.g. 0,
+	ErrCode  int `json:"err_code,omitempty"`  // e.g. 0
+}
+
+type setRelayStateMsg struct {
+	ErrCode int `json:"err_code,omitempty"`
+	State   int `json:"state,omitempty"`
+}

plug_test.go

@@ -2,6 +2,7 @@ package plugctl
 
 import (
 	"bytes"
+	"crypto/rand"
 	"encoding/base64"
 	"io"
 	"testing"
@@ -14,15 +15,15 @@ func TestDecrypt(t *testing.T) {
 	if err != nil {
 		t.Fatalf("base64.DecodeString(%q) error: %v", in64, err)
 	}
+	t.Logf("in[:4] = %v", in[:4])
 	in = in[4:]
 	want := []byte(`{"system":{"set_relay_state":{"state":1}}}`)
-	dec := newDecrypter(bytes.NewReader(in))
+	got, err := io.ReadAll(newDecrypter(bytes.NewReader(in)))
-	got, err := io.ReadAll(dec)
 	if err != nil {
 		t.Fatalf("io.ReadAll(decryptReader) error: %v", err)
 	}
 	if !bytes.Equal(got, want) {
-		t.Errorf("decrypt(%02x) = %q, want %q", in, got, want)
+		t.Errorf("io.ReadAll(decryptReader) = %q, want %q", got, want)
 	}
 }
 
@@ -36,19 +37,40 @@ func TestEncrypt(t *testing.T) {
 	want = want[4:]
 	in := []byte(`{"system":{"set_relay_state":{"state":1}}}`)
 	var buf bytes.Buffer
-	newEncrypter(&buf).Write(in)
+	if _, err := newEncrypter(&buf).Write(in); err != nil {
+		t.Fatalf("newEncrypter(buf).Write(in) error = %v", err)
+	}
 
 	if got := buf.Bytes(); !bytes.Equal(got, want) {
-		t.Errorf("encrypt(%q) = %02x, want %02x", in, got, want)
+		t.Errorf("buf.Bytes() = %02x, want %02x", got, want)
 	}
 }
 
-// func TestEncryptDecrypt(t *testing.T) {
+func TestEncryptDecrypt(t *testing.T) {
-// 	want := make([]byte, 64)
+	want := make([]byte, 64)
-// 	if _, err := rand.Read(want); err != nil {
+	if _, err := rand.Read(want); err != nil {
-// 		t.Fatalf("rand.Read(want) error: %v", err)
+		t.Fatalf("rand.Read(want) error: %v", err)
-// 	}
+	}
-// 	if got := decrypt(encrypt(want)); !bytes.Equal(got, want) {
+
-// 		t.Errorf("decrypt(encrypt(%02x)) = %02x, want %02x", want, got, want)
+	var buf bytes.Buffer
-// 	}
+	newEncrypter(&buf).Write(want)
-// }
+	got, err := io.ReadAll(newDecrypter(&buf))
+	if err != nil {
+		t.Fatalf("io.ReadAll(newDecrypter(&buf))")
+	}
+	if !bytes.Equal(got, want) {
+		t.Errorf("decrypt(encrypt(%02x)) = %02x, want %02x", want, got, want)
+	}
+}
+
+func TestReadStatusFromRealPlug(t *testing.T) {
+	//t.Skip("Hits the real device")
+
+	p := Plug{Addr: "192.168.86.10:9999"}
+
+	resp, err := p.roundTrip(reqGetSysinfo)
+	if err != nil {
+		t.Errorf("Plug.roundTrip(%v) error = %v", reqGetSysinfo, err)
+	}
+	t.Logf("Plug.roundTrip(%v) = %#v", reqGetSysinfo, *resp.System.GetSysInfo)
+}