Protocol decoding script, more dongle settings

decoder.py

@@ -0,0 +1,137 @@
+from Crypto.Cipher import AES
+import struct
+import json
+
+inEnc = False
+inSize = 0
+inCmd = 0
+inSet = False
+
+outEnc = False
+outCmd = 0
+outSize = 0
+outSet = False
+
+encKey = 0
+
+def build_iv_le(key):
+    iv = bytearray(16)
+    iv[1]  = (key >> 0) & 0xFF
+    iv[4]  = (key >> 8) & 0xFF
+    iv[9]  = (key >> 16) & 0xFF
+    iv[12] = (key >> 24) & 0xFF
+    return bytes(iv)
+
+def generate_key(key):
+    base = "SkBRDy3gmrw1ieH0"
+    key_bytes = bytearray(16)
+    for i in range(16):
+        key_bytes[i] = ord(base[(key + i) % 16])
+    return bytes(key_bytes)
+
+def decrypt_hex_cipher(ciphertext, intkey, iv_builder):
+    key = generate_key(intkey)
+    iv = iv_builder(intkey)
+    cipher = AES.new(key, AES.MODE_CFB, iv=iv, segment_size=128)
+    plaintext = cipher.decrypt(ciphertext)
+    return plaintext
+
+def bytes_to_printable_ascii(byte_data):
+    return ''.join((chr(b) if 32 <= b <= 126 else '.') for b in byte_data)
+
+def bytes_to_int_list_le(byte_data):
+    length = len(byte_data)
+    padded_length = (length + 3) // 4 * 4
+    padded = byte_data.ljust(padded_length, b'\x00')
+    return list(struct.unpack('<' + 'I' * (padded_length // 4), padded))
+
+def check_types(capdata: bytes) -> tuple[bool, bool]:
+    is_aa = capdata.startswith(bytes.fromhex('aa55aa55'))
+    is_bb = capdata.startswith(bytes.fromhex('bb55bb55'))
+    if is_aa or is_bb:
+        if len(capdata) >= 12:
+            size = int.from_bytes(capdata[4:8], 'little')
+            cmd = int.from_bytes(capdata[8:12], 'little')
+            return True, is_bb, size, cmd    
+    return False, False, None, None
+
+def processPacket(frame, out, capdata, cmd, size, enc):
+    global encKey
+    if enc and encKey != 0 and size > 0:
+        capdata = decrypt_hex_cipher(capdata, encKey, build_iv_le)
+    if out and cmd == 240 and size == 4 and len(capdata) >= 4:
+        encKey = int.from_bytes(capdata[0:4], 'little')
+    if cmd == 170:
+        return
+    res = f"{frame:>5}{cmd:>5} {'<' if not out else '>'}{' ' if not enc else '*'} {size:<5} : "
+    str = ""
+    if len(capdata)<1000:
+        str = bytes_to_printable_ascii(capdata)
+    else:
+        bts = ""
+        for i in range(0, min(len(capdata), 20), 4):
+            chunk = capdata[i:i+4]
+            val = int.from_bytes(chunk, 'little')
+            bts = bts+f"{val} "
+    if size == 4:
+        str = int.from_bytes(capdata[0:4], 'little')
+    print(f"{'\033[92m' if not out else '\033[93m'}{res}{str}\033[0m")
+    print(f"                    {' '.join(f'{b:02x}' for b in capdata[:20])}")
+    
+
+def processInc(frame, capdata):
+    global inEnc, inSize, inCmd, inSet
+    header, enc, size, cmd = check_types(capdata)
+    if header:
+        inEnc = enc
+        inSize = size
+        inCmd = cmd
+        inSet = header        
+        if inSize == 0:
+            processPacket(frame, False, bytearray(), inCmd, inSize, inEnc)
+        return
+
+    if inSet:
+        processPacket(frame, False, capdata, inCmd, inSize, inEnc)
+    inSet = header
+
+def processOut(frame, capdata):
+    global outEnc, outSize, outCmd, outSet
+    header, enc, size, cmd = check_types(capdata)
+    if header:
+        outEnc = enc
+        outSize = size
+        outCmd = cmd
+        outSet = header        
+        if outSize == 0:
+            processPacket(frame, True, bytearray(), outCmd, outSize, outEnc)
+        return
+
+    if outSet:
+        processPacket(frame, True, capdata, outCmd, outSize, outEnc)
+    outSet = header
+
+
+def processFile(file_path):
+    with open(file_path) as f:
+        data = json.load(f)
+
+    for entry in data:
+        layers = entry['_source']['layers']
+        usb = layers.get('usb', {})
+        frame_number = layers.get('frame', {}).get('frame.number')
+        direction = usb.get('usb.endpoint_address_tree', {}).get('usb.endpoint_address.direction')
+        urb_type = usb.get('usb.urb_type')
+        capdata = entry['_source']['layers'].get('usb.capdata')
+
+        if capdata:
+            byte_array = bytes(int(b, 16) for b in capdata.split(':'))
+            if (direction == "0" and urb_type == "'S'"):
+                processOut(frame_number, byte_array)
+            if(direction == "1" and urb_type == "'C'"):
+                processInc(frame_number, byte_array)
+
+print("This tool decode carlinkit protocol")
+print("It requred JSON export of USB events filtered by device")
+file_path = input("Path to JSON export from PCAPNG: ").strip().strip("'")
+processFile(file_path)

settings.txt

@@ -52,6 +52,18 @@
 # Nigh mode. 0 for day mode, 1 for night mode, 2 for automatic
 #night-mode = 2
 
+# Enable 5Ghz wifi. Otherwise will use 2,4Ghz
+#wifi-5 = true
+
+# Enable bluetooth audio. If enables the audio will be played not through the dongle but through bluetooth connection
+#bluetooth-audio = false
+
+# Microphone in use. Copied directly from carlinkit app.
+# 1 - Car
+# 2 - Box
+# 3 - Phone
+#mic-type = 1   
+
 # Target DPI reported to device. Set 0 for default. Not sure if it affects anything
 #dpi = 0
 

src/protocol.cpp

@@ -171,6 +171,15 @@ void Protocol::onDevice(bool connected)
         sendFile("/etc/box_name", "CarPlay");
         if (Settings::autoconnect)
             sendInt(CMD_CONTROL, 1002);
+        sendInt(CMD_CONTROL, Settings::bluetoothAudio ? 22 : 23);
+        sendInt(CMD_CONTROL, Settings::wifi5 ? 25 : 24);
+        int mic = 7;
+        if (Settings::micType == 2)
+            mic = 15;
+        if (Settings::micType == 3)
+            mic = 21;
+        sendInt(CMD_CONTROL, mic);
+
         if (Settings::encryption)
             sendEncryption();
     }

src/settings.h

@@ -24,7 +24,10 @@ public:
     static inline Setting<bool> autoconnect{"autoconnect", true};
     static inline Setting<bool> weakCharge{"weak-charge", true};
     static inline Setting<bool> leftDrive{"left-hand-drive", true};
-    static inline Setting<int> nightMode{"night-mode", 2};        
+    static inline Setting<int> nightMode{"night-mode", 2};     
+    static inline Setting<bool> wifi5{"wifi-5", true};   
+    static inline Setting<bool> bluetoothAudio{"bluetooth-audio", false};    
+    static inline Setting<int> micType{"mic-type", 1};               
     static inline Setting<int> dpi{"dpi", 0};
 
     // Application configuration section