Clean up device.py (#523)

* Clean up device.send_packet()

* Clean up device.auth()

* Clean up scan()

broadlink/device.py

@@ -3,13 +3,13 @@ import socket
 import threading
 import random
 import time
-from datetime import datetime
 from typing import Generator, Tuple, Union
 
 from cryptography.hazmat.backends import default_backend
 from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
 
 from .exceptions import check_error, exception
+from .protocol import Datetime
 
 HelloResponse = Tuple[int, Tuple[str, int], str, str, bool]
 
@@ -33,42 +33,13 @@ def scan(
         port = 0
 
     packet = bytearray(0x30)
-
+    packet[0x08:0x14] = Datetime.pack(Datetime.now())
-    timezone = int(time.timezone / -3600)
+    packet[0x18:0x1C] = socket.inet_aton(local_ip_address)[::-1]
-    if timezone < 0:
+    packet[0x1C:0x1E] = port.to_bytes(2, "little")
-        packet[0x08] = 0xFF + timezone - 1
-        packet[0x09] = 0xFF
-        packet[0x0A] = 0xFF
-        packet[0x0B] = 0xFF
-    else:
-        packet[0x08] = timezone
-        packet[0x09] = 0
-        packet[0x0A] = 0
-        packet[0x0B] = 0
-
-    year = datetime.now().year
-    packet[0x0C] = year & 0xFF
-    packet[0x0D] = year >> 8
-    packet[0x0E] = datetime.now().minute
-    packet[0x0F] = datetime.now().hour
-    subyear = str(year)[2:]
-    packet[0x10] = int(subyear)
-    packet[0x11] = datetime.now().isoweekday()
-    packet[0x12] = datetime.now().day
-    packet[0x13] = datetime.now().month
-
-    address = local_ip_address.split(".")
-    packet[0x18] = int(address[3])
-    packet[0x19] = int(address[2])
-    packet[0x1A] = int(address[1])
-    packet[0x1B] = int(address[0])
-    packet[0x1C] = port & 0xFF
-    packet[0x1D] = port >> 8
     packet[0x26] = 6
 
     checksum = sum(packet, 0xBEAF) & 0xFFFF
-    packet[0x20] = checksum & 0xFF
+    packet[0x20:0x22] = checksum.to_bytes(2, "little")
-    packet[0x21] = checksum >> 8
 
     start_time = time.time()
     discovered = []
@@ -81,18 +52,19 @@ def scan(
 
             while True:
                 try:
-                    response, host = conn.recvfrom(1024)
+                    resp, host = conn.recvfrom(1024)
                 except socket.timeout:
                     break
 
-                devtype = response[0x34] | response[0x35] << 8
+                devtype = resp[0x34] | resp[0x35] << 8
-                mac = bytes(reversed(response[0x3A:0x40]))
+                mac = resp[0x3A:0x40][::-1]
+
                 if (host, mac, devtype) in discovered:
                     continue
                 discovered.append((host, mac, devtype))
 
-                name = response[0x40:].split(b"\x00")[0].decode("utf-8")
+                name = resp[0x40:].split(b"\x00")[0].decode()
-                is_locked = bool(response[-1])
+                is_locked = bool(resp[-1])
                 yield devtype, host, mac, name, is_locked
     finally:
         conn.close()
@@ -123,7 +95,7 @@ class device:
         self.is_locked = is_locked
         self.count = random.randint(0x8000, 0xFFFF)
         self.iv = bytes.fromhex("562e17996d093d28ddb3ba695a2e6f58")
-        self.id = bytes(4)
+        self.id = 0
         self.type = "Unknown"
         self.lock = threading.Lock()
 
@@ -170,30 +142,10 @@ class device:
     def auth(self) -> bool:
         """Authenticate to the device."""
         payload = bytearray(0x50)
-        payload[0x04] = 0x31
+        payload[0x04:0x14] = [0x31]*16
-        payload[0x05] = 0x31
-        payload[0x06] = 0x31
-        payload[0x07] = 0x31
-        payload[0x08] = 0x31
-        payload[0x09] = 0x31
-        payload[0x0A] = 0x31
-        payload[0x0B] = 0x31
-        payload[0x0C] = 0x31
-        payload[0x0D] = 0x31
-        payload[0x0E] = 0x31
-        payload[0x0F] = 0x31
-        payload[0x10] = 0x31
-        payload[0x11] = 0x31
-        payload[0x12] = 0x31
         payload[0x1E] = 0x01
         payload[0x2D] = 0x01
-        payload[0x30] = ord("T")
+        payload[0x30:0x37] = "Test 1".encode()
-        payload[0x31] = ord("e")
-        payload[0x32] = ord("s")
-        payload[0x33] = ord("t")
-        payload[0x34] = ord(" ")
-        payload[0x35] = ord(" ")
-        payload[0x36] = ord("1")
 
         response = self.send_packet(0x65, payload)
         check_error(response[0x22:0x24])
@@ -203,7 +155,7 @@ class device:
         if len(key) % 16 != 0:
             return False
 
-        self.id = payload[0x03::-1]
+        self.id = int.from_bytes(payload[:0x4], "little")
         self.update_aes(key)
         return True
 
@@ -262,73 +214,47 @@ class device:
         """Return device type."""
         return self.type
 
-    def send_packet(self, command: int, payload: bytes) -> bytes:
+    def send_packet(self, packet_type: int, payload: bytes) -> bytes:
         """Send a packet to the device."""
         self.count = ((self.count + 1) | 0x8000) & 0xFFFF
         packet = bytearray(0x38)
-        packet[0x00] = 0x5A
+        packet[0x00:0x08] = bytes.fromhex("5aa5aa555aa5aa55")
-        packet[0x01] = 0xA5
+        packet[0x24:0x26] = self.devtype.to_bytes(2, "little")
-        packet[0x02] = 0xAA
+        packet[0x26:0x28] = packet_type.to_bytes(2, "little")
-        packet[0x03] = 0x55
+        packet[0x28:0x2a] = self.count.to_bytes(2, "little")
-        packet[0x04] = 0x5A
+        packet[0x2a:0x30] = self.mac[::-1]
-        packet[0x05] = 0xA5
+        packet[0x30:0x34] = self.id.to_bytes(4, "little")
-        packet[0x06] = 0xAA
+
-        packet[0x07] = 0x55
+        p_checksum = sum(payload, 0xBEAF) & 0xFFFF
-        packet[0x24] = self.devtype & 0xFF
+        packet[0x34:0x36] = p_checksum.to_bytes(2, "little")
-        packet[0x25] = self.devtype >> 8
-        packet[0x26] = command
-        packet[0x28] = self.count & 0xFF
-        packet[0x29] = self.count >> 8
-        packet[0x2A] = self.mac[5]
-        packet[0x2B] = self.mac[4]
-        packet[0x2C] = self.mac[3]
-        packet[0x2D] = self.mac[2]
-        packet[0x2E] = self.mac[1]
-        packet[0x2F] = self.mac[0]
-        packet[0x30] = self.id[3]
-        packet[0x31] = self.id[2]
-        packet[0x32] = self.id[1]
-        packet[0x33] = self.id[0]
 
-        # pad the payload for AES encryption
         padding = (16 - len(payload)) % 16
-        if padding:
+        payload = self.encrypt(payload + bytes(padding))
-            payload = bytearray(payload)
+        packet.extend(payload)
-            payload += bytearray(padding)
-
-        checksum = sum(payload, 0xBEAF) & 0xFFFF
-        packet[0x34] = checksum & 0xFF
-        packet[0x35] = checksum >> 8
-
-        payload = self.encrypt(payload)
-        for i in range(len(payload)):
-            packet.append(payload[i])
 
         checksum = sum(packet, 0xBEAF) & 0xFFFF
-        packet[0x20] = checksum & 0xFF
+        packet[0x20:0x22] = checksum.to_bytes(2, "little")
-        packet[0x21] = checksum >> 8
 
-        with self.lock:
+        with self.lock and socket.socket(socket.AF_INET, socket.SOCK_DGRAM) as conn:
-            with socket.socket(socket.AF_INET, socket.SOCK_DGRAM) as conn:
+            timeout = self.timeout
-                timeout = self.timeout
+            start_time = time.time()
-                start_time = time.time()
 
-                while True:
+            while True:
-                    time_left = timeout - (time.time() - start_time)
+                time_left = timeout - (time.time() - start_time)
-                    conn.settimeout(min(1, time_left))
+                conn.settimeout(min(1, time_left))
-                    conn.sendto(packet, self.host)
+                conn.sendto(packet, self.host)
 
-                    try:
+                try:
-                        resp = conn.recvfrom(2048)[0]
+                    resp = conn.recvfrom(2048)[0]
-                        break
+                    break
-                    except socket.timeout:
+                except socket.timeout:
-                        if (time.time() - start_time) > timeout:
+                    if (time.time() - start_time) > timeout:
-                            raise exception(-4000)  # Network timeout.
+                        raise exception(-4000)  # Network timeout.
 
         if len(resp) < 0x30:
             raise exception(-4007)  # Length error.
 
-        checksum = resp[0x20] | (resp[0x21] << 8)
+        checksum = int.from_bytes(resp[0x20:0x22], "little")
         if sum(resp, 0xBEAF) - sum(resp[0x20:0x22]) & 0xFFFF != checksum:
             raise exception(-4008)  # Checksum error.
 

broadlink/protocol.py

@@ -0,0 +1,49 @@
+import datetime as dt
+import time
+
+
+class Datetime:
+    """Helps to pack and unpack datetime objects for the Broadlink protocol."""
+
+    @staticmethod
+    def pack(datetime: dt.datetime) -> bytes:
+        """Pack the timestamp to be sent over the Broadlink protocol."""
+        data = bytearray(12)
+        utcoffset = int(datetime.utcoffset().total_seconds() / 3600)
+        data[:0x04] = utcoffset.to_bytes(4, "little", signed=True)
+        data[0x04:0x06] = datetime.year.to_bytes(2, "little")
+        data[0x06] = datetime.minute
+        data[0x07] = datetime.hour
+        data[0x08] = int(datetime.strftime('%y'))
+        data[0x09] = datetime.isoweekday()
+        data[0x0A] = datetime.day
+        data[0x0B] = datetime.month
+        return data
+
+    @staticmethod
+    def unpack(data: bytes) -> dt.datetime:
+        """Unpack a timestamp received over the Broadlink protocol."""
+        utcoffset = int.from_bytes(data[0x00:0x04], "little", signed=True)
+        year = int.from_bytes(data[0x04:0x06], "little")
+        minute = data[0x06]
+        hour = data[0x07]
+        subyear = data[0x08]
+        isoweekday = data[0x09]
+        day = data[0x0A]
+        month = data[0x0B]
+
+        tz_info = dt.timezone(dt.timedelta(hours=utcoffset))
+        datetime = dt.datetime(year, month, day, hour, minute, 0, 0, tz_info)
+
+        if datetime.isoweekday() != isoweekday:
+            raise ValueError("isoweekday does not match")
+        if int(datetime.strftime('%y')) != subyear:
+            raise ValueError("subyear does not match")
+
+        return datetime
+
+    @staticmethod
+    def now() -> dt.datetime:
+        """Return the current date and time with timezone info."""
+        tz_info = dt.timezone(dt.timedelta(seconds=-time.timezone))
+        return dt.datetime.now(tz_info)