add a python3 DBUs Bluetooth LE Service Discovery beacon controller

This commit is contained in:
F. Duncanh
2025-10-26 01:48:28 -04:00
parent 6d899820fb
commit 63f62e9f74
8 changed files with 705 additions and 553 deletions

View File

@@ -0,0 +1,456 @@
#!/usr/bin/env python3
# SPDX-License-Identifier: LGPL-2.1-or-later
# adapted from https://github.com/bluez/bluez/blob/master/test/example-advertisement
#----------------------------------------------------------------
# a standalone python-3.6 or later DBus-based AirPlay Service-Discovery Bluetooth LE beacon for UxPlay
# (c) F. Duncanh, October 2025
import argparse
import gi
import os
import sys
import psutil
import struct
import socket
from gi.repository import GLib
import dbus
import dbus.exceptions
import dbus.mainloop.glib
import dbus.service
import time
import threading
ad_manager = None
airplay_advertisement = None
port = int(0)
advmin = int(100)
advmax = int(100)
ipv4_str = "ipv4_address"
index = int(0)
BLUEZ_SERVICE_NAME = 'org.bluez'
LE_ADVERTISING_MANAGER_IFACE = 'org.bluez.LEAdvertisingManager1'
DBUS_OM_IFACE = 'org.freedesktop.DBus.ObjectManager'
DBUS_PROP_IFACE = 'org.freedesktop.DBus.Properties'
LE_ADVERTISEMENT_IFACE = 'org.bluez.LEAdvertisement1'
class InvalidArgsException(dbus.exceptions.DBusException):
_dbus_error_name = 'org.freedesktop.DBus.Error.InvalidArgs'
class NotSupportedException(dbus.exceptions.DBusException):
_dbus_error_name = 'org.bluez.Error.NotSupported'
class NotPermittedException(dbus.exceptions.DBusException):
_dbus_error_name = 'org.bluez.Error.NotPermitted'
class InvalidValueLengthException(dbus.exceptions.DBusException):
_dbus_error_name = 'org.bluez.Error.InvalidValueLength'
class FailedException(dbus.exceptions.DBusException):
_dbus_error_name = 'org.bluez.Error.Failed'
class AirPlay_Service_Discovery_Advertisement(dbus.service.Object):
PATH_BASE = '/org/bluez/airplay_service_discovery_advertisement'
def __init__(self, bus, index):
self.path = self.PATH_BASE + str(index)
self.bus = bus
self.manufacturer_data = None
self.min_intrvl = 0
self.max_intrvl = 0
dbus.service.Object.__init__(self, bus, self.path)
def get_properties(self):
properties = dict()
properties['Type'] = 'broadcast'
if self.manufacturer_data is not None:
properties['ManufacturerData'] = dbus.Dictionary(
self.manufacturer_data, signature='qv')
if self.min_intrvl > 0:
properties['MinInterval'] = dbus.UInt32(self.min_intrvl)
if self.max_intrvl > 0:
properties['MaxInterval'] = dbus.UInt32(self.max_intrvl)
return {LE_ADVERTISEMENT_IFACE: properties}
def get_path(self):
return dbus.ObjectPath(self.path)
def add_manufacturer_data(self, manuf_code, manuf_data):
if not self.manufacturer_data:
self.manufacturer_data = dbus.Dictionary({}, signature='qv')
self.manufacturer_data[manuf_code] = dbus.Array(manuf_data, signature='y')
def set_min_intrvl(self, min_intrvl):
if self.min_intrvl == 0:
self.min_intrvl = 100
self.min_intrvl = max(min_intrvl, 100)
def set_max_intrvl(self, max_intrvl):
if self.max_intrvl == 0:
self.max_intrvl = 100
self.max_intrvl = max(max_intrvl, 100)
@dbus.service.method(DBUS_PROP_IFACE,
in_signature='s',
out_signature='a{sv}')
def GetAll(self, interface):
if interface != LE_ADVERTISEMENT_IFACE:
raise InvalidArgsException()
return self.get_properties()[LE_ADVERTISEMENT_IFACE]
@dbus.service.method(LE_ADVERTISEMENT_IFACE,
in_signature='',
out_signature='')
def Release(self):
print('%s: Released!' % self.path)
class AirPlayAdvertisement(AirPlay_Service_Discovery_Advertisement):
def __init__(self, bus, index, ipv4_str, port, min_intrvl, max_intrvl):
AirPlay_Service_Discovery_Advertisement.__init__(self, bus, index)
assert port > 0
assert port <= 65535
mfg_data = bytearray([0x09, 0x08, 0x13, 0x30]) # Apple Data Unit type 9 (Airplay), length 8, flags 0001 0011, seed 30
import ipaddress
ipv4_address = ipaddress.ip_address(ipv4_str);
ipv4 = bytearray(ipv4_address.packed);
mfg_data.extend(ipv4)
port_bytes = port.to_bytes(2, 'big')
mfg_data.extend(port_bytes)
self.add_manufacturer_data(0x004c, mfg_data)
self.set_min_intrvl(min_intrvl)
self.set_max_intrvl(max_intrvl)
def register_ad_cb():
global ipv4_str
global port
print(f'AirPlay Service_Discovery Advertisement ({ipv4_str}:{port}) registered')
def register_ad_error_cb(error):
print('Failed to register advertisement: ' + str(error))
mainloop.quit()
def find_adapter(bus):
remote_om = dbus.Interface(bus.get_object(BLUEZ_SERVICE_NAME, '/'),
DBUS_OM_IFACE)
objects = remote_om.GetManagedObjects()
for o, props in objects.items():
if LE_ADVERTISING_MANAGER_IFACE in props:
return o
return None
def setup_beacon(ipv4_str, port, advmin, advmax, index):
global ad_manager
global airplay_advertisement
dbus.mainloop.glib.DBusGMainLoop(set_as_default=True)
bus = dbus.SystemBus()
adapter = find_adapter(bus)
if not adapter:
print('LEAdvertisingManager1 interface not found')
return
adapter_props = dbus.Interface(bus.get_object(BLUEZ_SERVICE_NAME, adapter),
"org.freedesktop.DBus.Properties")
adapter_props.Set("org.bluez.Adapter1", "Powered", dbus.Boolean(1))
ad_manager = dbus.Interface(bus.get_object(BLUEZ_SERVICE_NAME, adapter),
LE_ADVERTISING_MANAGER_IFACE)
airplay_advertisement = AirPlayAdvertisement(bus, index, ipv4_str, port, advmin, advmax)
def beacon_on():
global ad_manager
ad_manager.RegisterAdvertisement(airplay_advertisement.get_path(), {},
reply_handler=register_ad_cb,
error_handler=register_ad_error_cb)
def beacon_off():
global ad_manager
global airplay_advertisement
ad_manager.UnregisterAdvertisement(airplay_advertisement)
print(f'AirPlay Service-Discovery beacon advertisement unregistered')
ad_manager = None
dbus.service.Object.remove_from_connection(airplay_advertisement)
airplay_advertisement = None
#==generic code (non-dbus) below here =============
# global variables
beacon_is_running = False
beacon_is_pending_on = False
beacon_is_pending_off = False
def start_beacon():
global beacon_is_running
global port
global ipv4_str
global advmin
global advmax
global index
setup_beacon(ipv4_str, port, advmin, advmax, index)
beacon_on()
beacon_is_running = True
def stop_beacon():
global beacon_is_running
beacon_off()
beacon_is_running = False
def check_process_name(pid, pname):
try:
process = psutil.Process(pid)
if process.name().find(pname,0) == 0:
return True
else:
return False
except psutil.NoSuchProcess:
return False
def check_pending():
global beacon_is_running
global beacon_is_pending_on
global beacon_is_pending_off
if beacon_is_running:
#print(f"beacon running")
if beacon_is_pending_off:
stop_beacon()
beacon_is_pending_off = False
else:
#print(f"beacon not running")
if beacon_is_pending_on:
start_beacon()
beacon_is_pending_on = False
return True
def check_file_exists(file_path):
global port
global beacon_is_running
global beacon_is_pending_on
global beacon_is_pending_off
if os.path.exists(file_path):
with open(file_path, 'rb') as file:
data = file.read(2)
port = struct.unpack('<H', data)[0]
data = file.read(4)
pid = struct.unpack('<I', data)[0]
data = file.read(16)
pname = data.split(b'\0',1)[0].decode('utf-8')
last_element_of_pname = os.path.basename(pname)
test = check_process_name(pid, last_element_of_pname)
if test == True:
if not beacon_is_running:
beacon_is_pending_on = True
else:
print(f"orphan beacon file {file_path} exists, but process {pname} (pid {pid}) is no longer active")
try:
os.remove(file_path)
print(f"File '{file_path}' deleted successfully.")
except FileNotFoundError:
print(f"File '{file_path}' not found.")
if beacon_is_running:
beacon_is_pending_off = True
else:
if beacon_is_running:
beacon_is_pending_off = True
def on_timeout(file_path):
check_file_exists(file_path)
return True
def process_input(value):
try:
my_integer = int(value)
return my_integer
except ValueError:
printf(f"Error: could not convert '{value}' to integer: {my_integer}")
return None
#check AdvInterval
def check_adv_intrvl(min, max):
if not (100 <= min):
raise ValueError("AdvMin was smaller than 100 msecs")
if not (max >= min):
raise ValueError("AdvMax was smaller than AdvMin")
if not (max <= 10240):
raise ValueError("AdvMax was larger than 10240 msecs")
def main(file_path, ipv4_str_in, advmin_in, advmax_in, index_in):
global ipv4_str
global advmin
global advmax
global index
ipv4_str = ipv4_str_in
advmin = advmin_in
advmax = advmax_in
index = index_in
try:
while True:
try:
check_adv_intrvl(advmin, advmax)
except ValueError as e:
print(f"Error: {e}")
raise SystemExit(1)
GLib.timeout_add_seconds(5, on_timeout, file_path)
GLib.timeout_add_seconds(1, check_pending)
mainloop = GLib.MainLoop()
mainloop.run()
except KeyboardInterrupt:
print(f"\nExiting ...")
sys.exit(0)
if __name__ == '__main__':
# Create an ArgumentParser object
parser = argparse.ArgumentParser(
description='A program that runs an AirPlay service discovery BLE beacon.',
epilog='Example: python beacon.py --ipv4 "192.168.1.100" --path "/home/user/ble" --AdvMin 100 --AdvMax 100"'
)
home_dir = os.path.expanduser("~")
# Add arguments
parser.add_argument(
'--file',
type=str,
default= home_dir + "/.uxplay.beacon",
help='beacon startup file (optional): one entry (key, value) per line, e.g. --ipv4 192.168.1.100, (lines startng with with # are ignored)'
)
parser.add_argument(
'--path',
type=str,
default= home_dir + "/.uxplay.ble",
help='path to AirPlay server BLE beacon information file (default: ~/.uxplay.ble)).'
)
parser.add_argument(
'--ipv4',
type=str,
default='use gethostbyname',
help='ipv4 address of AirPlay server (default: use gethostbyname).'
)
parser.add_argument(
'--AdvMin',
type=str,
default="0",
help='The minimum Advertising Interval (>= 100) units=msec, default 100)'
)
parser.add_argument(
'--AdvMax',
type=str,
default="0",
help='The maximum Advertising Interval (>= AdvMin, <= 10240) units=msec, default 100)'
)
parser.add_argument(
'--index',
type=str,
default="0",
help='use index >= 0 to distinguish multiple AirPlay Service Discovery beacons, default 0)'
)
# Parse the command-line argunts
args = parser.parse_args()
ipv4_str = None
path = None
advmin = int(100)
advmax = int(100)
index = int(0)
if args.file:
print(f"Using config file: {args.file}")
if os.path.exists(args.file):
with open(args.file, 'r') as file:
for line in file:
stripped_line = line.strip()
if stripped_line.startswith('#'):
continue
parts = stripped_line.partition(" ")
part0 = parts[0]
part2 = parts[2]
key = part0.strip()
value = part2.strip()
if key == "--path":
path = value
elif key == "--ipv4":
ipv4_str = value
elif key == "--AdvMin":
if value.isdigit():
advmin = int(value)
else:
print(f"Invalid config file input (--AdvMin) {value} in {args.file}")
raise SystemExit(1)
elif key == "--AdvMax":
if value.isdigit():
advmax = int(value)
else:
print(f"Invalid config file input (--AdvMax) {value} in {args.file}")
raise SystemExit(1)
elif key == "--index":
if value.isdigit():
index = int(value)
else:
print(f"Invalid config file input (--index) {value} in {args.file}")
raise SystemExit(1)
else:
print(f"Unknown key \"{key}\" in config file {args.file}")
raise SystemExit(1)
if args.ipv4 == "use gethostbyname":
if (ipv4_str is None):
ipv4_str = socket.gethostbyname(socket.gethostname())
else:
ipv4_str = args.ipv4
if args.AdvMin != "0":
if args.AdvMin.isdigit():
advmin = int(args.AdvMin)
else:
print("Invalid input (AdvMin) {args.AdvMin}")
raise SystemExit(1)
if args.AdvMax != "0":
if args.AdvMax.isdigit():
advmax = int(args.AdvMax)
else:
print("Invalid input (AdvMin) {args.AdvMin}")
raise SystemExit(1)
if args.index != "0":
if args.index.isdigit():
index = int(args.index)
else:
print("Invalid input (AdvMin) {args.AdvMin}")
raise SystemExit(1)
if index < 0:
raise ValueError("index was negative (forbidden)")
print(f"AirPlay Service-Discovery Bluetooth LE beacon: using BLE file {args.path}, advmin:advmax {advmin}:{advmax} index:{index}")
print(f"(Press Ctrl+C to exit)")
main(args.path, ipv4_str, advmin, advmax, index)

View File

@@ -75,6 +75,14 @@ install( FILES README.md README.txt README.html LICENSE DESTINATION ${CMAKE_INST
install( FILES lib/llhttp/LICENSE-MIT DESTINATION ${CMAKE_INSTALL_DOCDIR}/llhttp )
install( FILES uxplay.service DESTINATION ${CMAKE_INSTALL_DOCDIR}/systemd )
if (DBUS_FOUND)
install( FILES Bluetooth_LE_beacon/dbus/uxplay-beacon.py
DESTINATION bin
PERMISSIONS OWNER_EXECUTE OWNER_WRITE OWNER_READ GROUP_EXECUTE GROUP_READ WORLD_EXECUTE WORLD_READ)
install( FILES uxplay-beacon.1 DESTINATION ${CMAKE_INSTALL_MANDIR}/man1 )
endif()
# uninstall target
if(NOT TARGET uninstall)
configure_file(

View File

@@ -15,12 +15,14 @@ Bluetooth LE “beacon”, (a USB 4.0 or later “dongle” can be used). See
instructions below. The beacon runs independently of UxPlay and
regularly broadcasts a Bluetooth LE (“Low Energy”) 46 byte packet
informing nearby iOS/macOS devices of the local IPv4 network address of
the UxPlay server, and which TCP port to contact UxPlay on. Instructions
for manually setting up such a beacon in Linux are <a
href="#bluetooth-le-beacon-setup">given below</a>. <strong>It is hoped
that users will submit Pull Requests contributing scripts for automating
beacon setup on all platforms. (Python may be an appropriate language
choice)</strong></p></li>
the UxPlay server, and which TCP port to contact UxPlay on. A python
script (Python &gt;=3.6) “uxplay-beacon.py”, to broadcast the
Service-Discovery advertisement will be installed on systems with DBus
support (Linux and *BSD, using Bluez for Bluetooth control): this does
<strong>not</strong> require enhanced “root permissions” to run. A
windows version of this script is also planned for the future.
Instructions are <a href="#bluetooth-le-beacon-setup">given
below</a>.</p></li>
<li><p><strong>NEW on github</strong>: option
<code>-vrtp &lt;rest-of-pipeline&gt;</code> bypasses rendering by
UxPlay, and instead transmits rtp packets of decrypted h264 or h265
@@ -1437,11 +1439,12 @@ to a file to <em>n</em> or less. To change the name <em>audiodump</em>,
use -admp [n] <em>filename</em>. <em>Note that (unlike dumped video) the
dumped audio is currently only useful for debugging, as it is not
containerized to make it playable with standard audio players.</em></p>
<p><strong>-ble <em>filename</em></strong>. Enable Bluetooth beacon
Service Discovery. The PID and process name of the UxPlay process is
recorded in <em>filename</em>, which must be the full path to a
writeable file. (This file is created when UxPlay starts and deleted
when it stops.) <strong>See below for beacon setup
<p><strong>-ble [<em>filename</em>]</strong>. Enable Bluetooth beacon
Service Discovery. The port, PID and process name of the UxPlay process
is recorded by default in <code>~/.uxplay.ble</code> : (this file is
created when UxPlay starts and deleted when it stops.) Optionally the
file <em>filename</em>, which must be the full path to a writeable file
can instead be used. <strong>See below for beacon setup
instructions.</strong></p>
<p><strong>-d [n]</strong> Enable debug output; optional argument n=1
suppresses audio/video packet data in debug output. Note: this does not
@@ -1451,191 +1454,65 @@ GST_DEBUG=2” before running uxplay. To see GStreamer information
messages, set GST_DEBUG=4; for DEBUG messages, GST_DEBUG=5; increase
this to see even more of the GStreamer inner workings.</p>
<h1 id="bluetooth-le-beacon-setup">Bluetooth LE beacon setup</h1>
<p>To allow UxPlay to work with Bluetooth Low Energy (LE) Service
Discovery, as an alternative to DNS-SD (Bonjour/Rendezvous) service
discovery, start it with the option
<code>-ble &lt;path-to-writeable-file&gt;</code>”, which at startup
writes a data file containing the uxplay TCP port for receiving replies
to the advertisement, plus the uxplay process ID and process name, and
is deleted when uxplay terminates normally. <strong>This file is not
used in the simple manual method for creating a beacon described
below</strong>.</p>
<p>Bluetooth LE Service discovery uses a “beacon” broadcasting a simple
14-byte advertisement
<code>0D FF 4C 00 09 08 13 30 XX XX XX XX YY YY</code>” where XX XX XX
XX is an IPv4 internet address (and port YY YY) of the UxPlay host
translated into hexadecimal octets. For example,
<code>XX XX XX XX YY YY</code>” = “<code>C0 A8 01 FD 1B 58</code>
means 192.168.1.253 port 0x1b58 (decimal value 7000). UxPlay must be
able to receive messages on this TCP port at this address. The uxplay
option “<code>-p</code>” sets up uxplay to listen on the default port
7000 for these messages, as used in the example above. Otherwise the
port in the beacon message should be the first (<code>&lt;n&gt;</code>)
of the 3 open TCP ports specified with uxplay option
<code>-p &lt;n&gt;</code>. If the <code>-p</code> option is not used
(which is only possible if there is no active firewall) the TCP port is
selected at random, and its value must be taken from the beginning of
the file written with the <code>-ble</code> option.</p>
<p>The full translation of this message is that it has length 0D = 0x0d
= 13 octets, and is a single “Advertising Protocol Data Unit” (PDU) of
type “<code>FF</code>”, called “Manufacturer-Specific Data”, with
“manufacturer code” “<code>4C 00</code>” = 0x004c = Apple (note the
reversal of octet order when two octets are combined to make a two-byte
unsigned short integer), and
<code>09 08 13 30 XX XX XX XX YY YY</code>” is the Apple-specific
data.</p>
<p>The Apple-specific data contains a single Apple Data Unit with Apple
type = 09 (Airplay), Apple Data length 08 (0x08 = 8 octets) and Apple
Data “<code>13 30 XX XX XX XX YY YY</code>” where 13 = 0001 0011 is
Apple Flags, 30 is a seed (which will be ignored), XX XX XX XX is the
IPv4 internet address and YY YY is the port. This is smaller than the
“iBeacon” Apple Data Unit, which has Apple type 02 and Apple length 15
(0x15 = 21 octets).</p>
<p>In addition to creating the message, we need to set the “Advertising
type” (ADV_NONCONN_IND) and “Advertising interval” range [AdvMin,
AdvMax], where 0x00a0 = 100 msec &lt;= AdvMin &lt;= AdvMax &lt;= 0x4000
= 10.24 sec (intervals are given in units of 0.625 msec as uint16_t
unsigned short integers). Setting AdvMin = AdvMax fixes the interval;
AdvMin &lt; AdvMax allows the choice of the time of each advertising
broadcast to be flexible within an allowed window to avoid clashing with
other Bluetooth tasks. Keep the default choice to broadcast
simultaneously on all three advertising channels, 37,38,39.</p>
<p>An automated script to setup and start the beacon should use a
high-level interface such as: (Linux) Bluez <a
href="https://manpages.opensuse.org/Leap-16.0/bluez/org.bluez.LEAdvertisement.5.en.html">LEAdvertisingManager1</a>
(with an <a
href="https://github.com/bluez/bluez/blob/master/test/example-advertisement">example</a>)
and (Windows 10/11) <a
href="https://learn.microsoft.com/en-us/uwp/api/windows.devices.bluetooth.advertisement.bluetoothleadvertisementpublisher">BluetoothLEAdvertisementPublisherClass</a>
(with an <a
href="https://github.com/MicrosoftDocs/windows-dev-docs/blob/docs/uwp/devices-sensors/ble-beacon.md">example</a>).
<strong>We invite submission of Pull Requests for working
implementations!</strong></p>
<p>Until automated scripts are available, a simple Linux-only low-level
manual method is given below, using the <code>hcitool</code> and
<code>hciconfig</code> utilities which directly access the HCI stack,
and need elevated privileges (use <code>sudo</code>). These utilities
have been declared “deprecated” and “obsolete” by BlueZ developers: on
Debian-based Linux “<code>sudo apt install bluez</code>” still provides
<code>hcitool</code>, but on some other Linux distributions, it is split
off from the main BlueZ package into an “extra” package with a name like
“bluez-deprecated”. If we get the AirPlay beacon to work using the newer
<code>bluetoothctl</code> or <code>btmgmt</code> utilities, these
instructions will be updated.</p>
<p>First verify that a Bluetooth HCI interface is available:</p>
<pre><code>$hcitool dev
Devices:
hci1 E8:EA:6A:7C:3F:CC
hci0 08:BE:AC:40:A9:DC</code></pre>
<p>This shows two devices with their MAC addresses. You can use
<code>hciconfig -a</code>” to see which versions of Bluetooth they
implement: we require Bluetooth v4.0 or later; you may need to use a
cheap USB Bluetooth dongle if your system does not have it, or will not
let you use it for LE (Low Energy) transmissions.<br />
Choose which interface to use (we will use hci0), and reset it.</p>
<pre><code>$ sudo hciconfig hci0 reset
</code></pre>
<p><strong>Step 1.</strong> Configure the beacon by sending a configure
command 0x0006 to the Bluetooth LE stack 0x08. <code>hcitool</code>
echoes the HCI command and the 4-byte “HCI Event” response. The only
important part of the response is that the last byte is
<code>00</code>” (= “success”: other values are error codes):</p>
<pre><code>
$ sudo hcitool -i hci0 cmd 0x08 0x0006 0xa0 0x00 0xa0 0x00 0x03 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x07 0x00
&lt; HCI Command: ogf 0x08, ocf 0x0006, plen 15
A0 00 A0 00 03 00 00 00 00 00 00 00 00 07 00
&gt; HCI Event: 0x0e plen 4
02 06 20 00
</code></pre>
<p>The first “<code>0xa0 0x00</code>” sets AdvMin = 0x00a0 = 100 msec.
The second “<code>0xa0 0x00</code>” sets AdvMax = 0x00a0 = 100 msec.
Then “<code>0x03</code>” sets the Advertising Type to ADV_NONCONN_IND.
The other non-zero entry (0x07 = 0000 0111) is the flag for using all
three advertising channels.</p>
<p>An Apple TV (Gen 3) seems to use AdvMin = AdvMax = 180 msec = 0x0120
(“<code>0x20 0x01</code>”).</p>
<p><strong>Step 2.</strong> Set the advertising message with HCI LE
command 0x0008. For this command, hcitool requires a 32 octet message
after <code>sudo hcitool -i hci0 cmd 0x08 0x0008</code>: The first octet
is the length 0E = 0x0e = 14 of the “significant part” of the following
31 octets, followed by the 14 octets of the advertisement, then padded
with 17 zeroes to a total length of 32 octets. The example below sends
an IPv4 address 192.168.1.253 as “<code>0xc0 0xa8 0x01 0xfd</code>” and
the TCP port as 0x1b 0x58 (port 7000 = 0x1b58):</p>
<pre><code>$ sudo hcitool -i hci0 cmd 0x08 0x0008 0x0e 0x0d 0xff 0x4c 0x00 0x09 0x08 0x13 0x30 0xc0 0xa8 0x01 0xfd 0x1b 0x58 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
&lt; HCI Command: ogf 0x08, ocf 0x0008, plen 32
0E 0D FF 4C 00 09 08 13 30 C0 A8 01 FD 1B 58 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00
&gt; HCI Event: 0x0e plen 4
01 08 20 00 </code></pre>
<p><strong>Step 3</strong>. Start the beacon with a 1-byte message
<code>0x01</code>” = “on”, sent with HCI LE command 0x000a = 10:</p>
<pre><code>$ sudo hcitool -i hci0 cmd 0x08 0x000a 0x01
&lt; HCI Command: ogf 0x08, ocf 0x000a, plen 1
01
&gt; HCI Event: 0x0e plen 4
02 0A 20 00 </code></pre>
<p>The full length of the broadcasted beacon message is 46 bytes. To
stop the beacon, use this command to send the 1-byte message
<code>0x00</code>” = “off”.</p>
<p>The python&gt;=3.6 script for running a Bluetooth-LE Service
Discovery beacon is uxplay-beacon.py. Currently only a DBus version (for
Linux and *BSD) is available, and it is only installed on systems which
support DBus.</p>
<p>If uxplay will be run with option “<code>uxplay -ble</code>” (so it
writes data for the Bluetooth beacon in the default BLE data file
<code>~/.uxplay.ble</code>), just run <code>uxplay-beacon.py</code> in a
separate terminal. The python script will start Bluetooth LE
Service-Discovery advertising when it detects that UxPlay is running by
checking if the BLE data file exists, and stop when it no longer detects
a running UxPlay plus this file (it will restart advertising if UxPlay
later reappears). The script will remain active until stopped with
Ctrl+C in its terminal window (or its terminal window is closed).</p>
<p>The beacon script can be more finely controlled using five possible
options: these can be given on the command line, or read from a
configuration file <code>~/.uxplay.beacon</code>, if it exists.
Configuration file entries are like the command line forms, one per line
(e.g., <code>--ipv4 192.168.1.100</code>). Lines commented out with an
initial <code>#</code> are ignored. Command line options override the
configuration file options.</p>
<ul>
<li>For testing Bluetooth beacon Service Discovery on Linux, you will
need to suppress the avahi-daemon which provides DNS-SD Service
Discovery on UxPlays Host system (replace <code>mask</code> and
<code>stop</code> below by <code>unmask</code> and <code>start</code> to
restore DNS-SD service):</li>
<li><p><code>--file &lt;config file&gt;</code> read beacon options from
<code>&lt;config file&gt;</code> instead of
<code>~/.uxplay.beacon</code>.</p></li>
<li><p><code>--ipv4 &lt;ipv4 address&gt;</code>. This option can be
used to specify the ipv4 address at which the UxPlay server should be
contacted by the client. If it is not given, an address will be obtained
automatically using <code>gethostbyname</code>. Only ipv4 addresses are
supported.</p></li>
<li><p><code>--path &lt;BLE data file&gt;</code>. This overrides the
default choice of BLE data file (<code>~/.uxplay.ble</code>) that is
monitored by the beacon script. This also requires that uxplay is run
with option “<code>uxplay -ble &lt;BLE data file&gt;</code>”.</p></li>
<li><p><code>--AdvMin x</code>, <code>--AdvMax y</code>. These controls
the interval between BLE advertisement broadcasts. This interval is in
the range [x, y], given in units of msecs. Allowed ranges are 100 &lt;=
x &lt;= y &lt;= 10240. If AdvMin=AdvMax, the interval is fixed: if
AdvMin &lt; AdvMax it is chosen flexibly in this range to avoid
interfering with other tasks the Bluetooth device is carrying out. The
default values are AdvMin = AdvMax = 100. The advertisement is broadcast
on all three Bluetooth LE advertising channels: 37,38,39.</p></li>
<li><p><code>--index x</code> (default x = 0, x &gt;= 0). This should be
used to distinguish between multiple simultaneous instances of
uxplay-beacon.py that are running to support multiple instances of
UxPlay. Each instance must have its own BLE Data file (just as each
instance of UxPlay must also have its own MAC address and ports).
<em>Note: running multiple beacons simultaneously on the same host has
not been tested.</em></p></li>
</ul>
<p>If you wish to test Bluetooth LE Service Discovery on Linux/*BSD, you
can disable DNS_SD Service discovery by the avahi-daemon with</p>
<pre><code>$ sudo systemctl mask avahi-daemon.socket
$ sudo systemctl stop avahi-daemon</code></pre>
<p>An automated procedure for creating the beacon would presumably want
to switch it on when uxplay starts, and off when it stops. It has the
task of determing a host IPv4 address that the client can use to reach
uxplay. The 22-byte file created when uxplay starts (and deleted when it
stops) contains the RAOP port as a uint16_t unsigned short, in the first
2 bytes, followed by the uxplay PID as a uint32_t unsigned integer in
the next 4 bytes, then followed by up to the first 15 characters of the
process name (usually “uxplay”) as a null-terminated string, padded with
zeroes to 16 bytes. The port data identifies the port on the Host that
uxplay listens on, which should be included along with the Host IPv4
address in the advertisement broadcast by the beacon. The path to this
file is needed as the only input by the procedure when it is started.
The presence of the file should be checked at regular intervals (once
per second?). If it is absent, uxplay has stopped running, but if it
exists the process ID and process name of that PID should be checked to
handle cases where a new uxplay process has started, or if uxplay has
exited abnormally and failed to delete the file. (While it is probably
not an important use case, the possibility of concurrent uxplay
processes listening on different ports and writing different files could
be handled: the advertising protocol allows cycling between different
messages.)</p>
<p>This method above creates a beacon that identifies itself with a
“public Advertising Address” (the MAC hardware address of the Bluetooth
device). An Apple TV uses a private random address. If you wish to do
that, change the sixth octet (the one following <code>0x03</code>) in
Step 1 from “TxAdd” = <code>0x00</code> to TxAdd = <code>0x01</code>,
and add an intermediate “step 1.5”:</p>
<p><strong>Step 1.5</strong> Choose 6 random bytes r1, r2, r3, r4, r5,
r6, such as “<code>0x52 0xaa, 0xaa, 0x3a, 0xb4, 0x2f</code>”, and use
HCI LE command 0x0005 to set the random address:</p>
<pre><code>$sudo hcitool -i hci0 cmd 0x08 0x0005 0x52 0xaa 0xaa 0x3a 0xb4 0x2f
&lt; HCI Command: ogf 0x08, ocf 0x0005, plen 6
52 AA AA 3A B4 2F
&gt; HCI Event: 0x0e plen 4
02 05 20 00 </code></pre>
<p>On a Bluetooth packet sniffer with wireshark, this address displays
as: <strong>Advertising Address: 2f:b4:3a:aa:aa:52</strong>. In
principle, random byte r6 should be masked with 0x03 (r6 = r6 | 0x03) to
mark the address as a “static random private address”, but Apple TV does
not do this. In fact it updates to a new random Advertising Address
every 20 mins or so, increasing the seed in the Apple Data by 1 each
time. Apple TVs also add a length 2 type 0x01 (“Flags”) Advertising PDU
<code>0x02 0x01 0x1a</code>” in front of the main type 0xff
“Manufacturer-Specific Data” Advertising PDU in Step 2. This is
“optional” for ADV_NONCONN_IND advertisement type, and testing shows
that it can be dropped without affecting Service Discovery, which is
fortunate because the high-level Linux and Windows interfaces mentioned
earlier do not permit users to send a “Flags”-type PDU.</p>
<p>To restore DNS_SD Service discovery, replace “mask” by “unmask”, and
“stop” by start”.</p>
<p>For more information, see the <a
href="https://github.com/FDH2/UxPlay/wiki/Bluetooth_LE_beacon">wiki
page</a> This has useful information if you wish to build a python
beacon controller script for Windows (we would like to have one!).</p>
<ul>
<li><strong>Our current understanding is that Bluetooth LE AirPlay
Service Discovery only supports broadcast of IPv4 addresses. Please let

197
README.md
View File

@@ -5,10 +5,11 @@
- **NEW on github**: Support for **service discovery using a Bluetooth LE "beacon"** (as an alternative to Bonjour/Rendezvous DNS-SD
service discovery). The user must set up a Bluetooth LE "beacon", (a USB 4.0 or later "dongle" can be used). See instructions
below. The beacon runs independently of UxPlay and regularly broadcasts a Bluetooth LE ("Low Energy") 46 byte packet informing nearby iOS/macOS devices of
the local IPv4 network address of the UxPlay server, and which TCP port to contact UxPlay on.
Instructions for manually setting up such a beacon in Linux are [given below](#bluetooth-le-beacon-setup).
__It is hoped that users will submit Pull Requests contributing scripts for automating beacon setup on all platforms.
(Python may be an appropriate language choice)__
the local IPv4 network address of the UxPlay server, and which TCP port to contact UxPlay on. A python script (Python >=3.6) "uxplay-beacon.py",
to broadcast the Service-Discovery advertisement will be installed on systems with DBus support (Linux and *BSD, using Bluez for Bluetooth control):
this does **not** require enhanced "root permissions" to run.
A windows version of this script is also planned for the future.
Instructions are [given below](#bluetooth-le-beacon-setup).
- **NEW on github**: option `-vrtp <rest-of-pipeline>` bypasses rendering by UxPlay, and instead
transmits rtp packets of decrypted h264 or h265 video to
@@ -1452,10 +1453,13 @@ that (unlike dumped video) the dumped audio is currently only useful for
debugging, as it is not containerized to make it playable with standard
audio players.*
**-ble *filename***. Enable Bluetooth beacon Service Discovery.
The PID and process name of the UxPlay process is recorded in
*filename*, which must be the full path to a writeable file. (This file is created
when UxPlay starts and deleted when it stops.) __See below for beacon setup
**-ble [*filename*]**. Enable Bluetooth beacon Service Discovery.
The port, PID and process name of the UxPlay process is recorded by default in
`~/.uxplay.ble` : (this file is created
when UxPlay starts and deleted when it stops.)
Optionally the file
*filename*, which must be the full path to a writeable file can instead be used.
__See below for beacon setup
instructions.__
**-d \[n\]** Enable debug output; optional argument n=1 suppresses audio/video
@@ -1469,170 +1473,51 @@ GStreamer inner workings.
# Bluetooth LE beacon setup
To allow UxPlay to work with Bluetooth Low Energy (LE) Service Discovery, as an alternative to DNS-SD (Bonjour/Rendezvous)
service discovery, start it with the option "`-ble <path-to-writeable-file>`", which at startup writes a data file containing
the uxplay TCP port for receiving replies to the advertisement, plus the uxplay process ID and process name, and is deleted when uxplay terminates normally. **This file
is not used in the simple manual method for creating a beacon described below**.
The python>=3.6 script for running a Bluetooth-LE Service Discovery beacon is uxplay-beacon.py.
Currently only a DBus version (for Linux and *BSD) is available, and it is only installed on systems which
support DBus.
If uxplay will be run with option "`uxplay -ble`" (so it writes data for the Bluetooth beacon in the default BLE data file
`~/.uxplay.ble`), just run ``uxplay-beacon.py`` in a separate terminal. The python script will start
Bluetooth LE Service-Discovery advertising when it detects that UxPlay is running by checking if the BLE data file exists, and stop when it no longer detects
a running UxPlay plus this file (it will restart advertising if UxPlay later reappears). The script will remain active until stopped with Ctrl+C in its
terminal window (or its terminal window is closed).
Bluetooth LE Service discovery uses a "beacon" broadcasting a simple 14-byte
advertisement "`0D FF 4C 00 09 08 13 30 XX XX XX XX YY YY`" where XX XX XX XX is an IPv4 internet
address (and port YY YY) of the UxPlay host translated into hexadecimal octets. For
example, "`XX XX XX XX YY YY`" = "``C0 A8 01 FD 1B 58``" means 192.168.1.253 port 0x1b58 (decimal value 7000). UxPlay
must be able to receive messages on this TCP port at this
address. The uxplay option "`-p`" sets up uxplay to listen on the default port 7000 for these messages, as used in the
example above. Otherwise the port in the beacon message should
be the first (`<n>`) of the 3 open TCP ports specified with uxplay option ``-p <n>``. If
the `-p` option is not used (which is only possible if there is no active firewall) the TCP port is selected at random, and its value
must be taken from the beginning of the file written with the `-ble` option.
The beacon script can be more finely controlled using five possible options: these can be given on the command line, or read from
a configuration file `~/.uxplay.beacon`, if it exists. Configuration file entries are like the command line forms, one per line (e.g.,
`--ipv4 192.168.1.100`). Lines commented out with an initial ``#`` are ignored. Command line options override the configuration file
options.
The full translation of this message is that it has length 0D = 0x0d = 13 octets, and is a single "Advertising Protocol Data Unit" (PDU) of type "`FF`",
called "Manufacturer-Specific Data", with "manufacturer code" "`4C 00`" = 0x004c = Apple (note the reversal of octet order when
two octets are combined to make a two-byte unsigned short integer), and "`09 08 13 30 XX XX XX XX YY YY`" is the Apple-specific data.
* `--file <config file>` read beacon options from ``<config file>`` instead of
`~/.uxplay.beacon`.
The Apple-specific data contains a single Apple Data Unit with Apple type = 09 (Airplay), Apple Data length 08 (0x08 = 8 octets) and
Apple Data "`13 30 XX XX XX XX YY YY`" where 13 = 0001 0011 is Apple Flags, 30 is a seed (which will be ignored), XX XX XX XX
is the IPv4 internet address and YY YY is the port. This is smaller than the "iBeacon" Apple Data Unit, which has Apple type 02 and Apple length 15 (0x15 = 21 octets).
* `--ipv4 <ipv4 address>`. This option can be used to specify the ipv4 address at which the UxPlay server should be contacted by the client. If
it is not given, an address will be obtained automatically using `gethostbyname`. Only ipv4 addresses are supported.
In addition to creating the message, we need to set the "Advertising type" (ADV_NONCONN_IND) and "Advertising interval" range [AdvMin, AdvMax],
where 0x00a0 = 100 msec <= AdvMin <= AdvMax <= 0x4000 = 10.24 sec
(intervals are given in units of 0.625 msec as uint16_t unsigned short integers). Setting AdvMin = AdvMax fixes the interval; AdvMin < AdvMax allows the choice
of the time of each advertising broadcast to be flexible within an allowed window to avoid clashing with other Bluetooth tasks.
Keep the default choice to broadcast simultaneously on all three advertising channels, 37,38,39.
* `--path <BLE data file>`. This overrides the default choice of BLE data file (``~/.uxplay.ble``) that is monitored by the beacon script. This also requires
that uxplay is run with option "`uxplay -ble <BLE data file>`".
An automated script to setup and start the beacon should use a high-level interface
such as: (Linux) Bluez [LEAdvertisingManager1](https://manpages.opensuse.org/Leap-16.0/bluez/org.bluez.LEAdvertisement.5.en.html) (with
an [example](https://github.com/bluez/bluez/blob/master/test/example-advertisement))
and (Windows 10/11) [BluetoothLEAdvertisementPublisherClass](https://learn.microsoft.com/en-us/uwp/api/windows.devices.bluetooth.advertisement.bluetoothleadvertisementpublisher)
(with an [example](https://github.com/MicrosoftDocs/windows-dev-docs/blob/docs/uwp/devices-sensors/ble-beacon.md)).
**We invite submission of Pull Requests for working implementations!**
* `--AdvMin x`, ``--AdvMax y``. These controls the interval between BLE advertisement broadcasts. This interval is in the range
[x, y], given in units of msecs. Allowed ranges are 100 <= x <= y <= 10240. If AdvMin=AdvMax, the interval is fixed: if AdvMin < AdvMax
it is chosen flexibly in this range to avoid interfering with other tasks the Bluetooth device is carrying out. The default values are
AdvMin = AdvMax = 100. The advertisement is broadcast on all three Bluetooth LE advertising channels: 37,38,39.
Until automated scripts are available, a simple Linux-only low-level manual method
is given below, using the `hcitool` and ``hciconfig``
utilities which directly access the HCI stack, and need elevated privileges (use `sudo`). These utilities
have been declared "deprecated" and "obsolete" by BlueZ developers: on Debian-based Linux "`sudo apt install bluez`"
still provides `hcitool`, but on some other Linux distributions, it is split off from the main BlueZ package into an "extra" package
with a name like "bluez-deprecated". If we get the AirPlay beacon to work using the newer `bluetoothctl` or ``btmgmt`` utilities,
these instructions will be updated.
* `--index x` (default x = 0, x >= 0). This should be used to distinguish between multiple simultaneous instances of uxplay-beacon.py that are running to support multiple
instances of UxPlay. Each instance must have its own BLE Data file (just as each instance of UxPlay must also have its own MAC address and ports). _Note:
running multiple beacons simultaneously on the same host has not been tested._
First verify that a Bluetooth HCI interface is available:
```
$hcitool dev
Devices:
hci1 E8:EA:6A:7C:3F:CC
hci0 08:BE:AC:40:A9:DC
```
This shows two devices with their MAC addresses. You can use "`hciconfig -a`" to see which versions of Bluetooth they
implement: we require Bluetooth v4.0 or later;
you may need to use a cheap USB Bluetooth dongle if your system does not have it,
or will not let you use it for LE (Low Energy) transmissions.
Choose which interface to use (we will use hci0), and reset it.
```
$ sudo hciconfig hci0 reset
```
**Step 1.** Configure the beacon by sending a configure command 0x0006 to the Bluetooth LE stack 0x08. `hcitool` echoes the HCI command
and the 4-byte "HCI Event" response. The only important part of the response is that the last byte is "`00`" (= "success":
other values are error codes):
```
$ sudo hcitool -i hci0 cmd 0x08 0x0006 0xa0 0x00 0xa0 0x00 0x03 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x07 0x00
< HCI Command: ogf 0x08, ocf 0x0006, plen 15
A0 00 A0 00 03 00 00 00 00 00 00 00 00 07 00
> HCI Event: 0x0e plen 4
02 06 20 00
```
The first "`0xa0 0x00`" sets AdvMin = 0x00a0 = 100 msec. The second "``0xa0 0x00``" sets AdvMax = 0x00a0 = 100 msec.
Then "`0x03`" sets the Advertising Type to ADV_NONCONN_IND. The other non-zero entry (0x07 = 0000 0111) is the flag for using
all three
advertising channels.
An Apple TV (Gen 3) seems to use AdvMin = AdvMax = 180 msec = 0x0120 ("`0x20 0x01`").
**Step 2.** Set the advertising message with HCI LE command 0x0008. For this command, hcitool requires a 32 octet message after
`sudo hcitool -i hci0 cmd 0x08 0x0008`: The first octet is the length 0E = 0x0e = 14 of the "significant part" of the following 31 octets,
followed by the 14 octets of the advertisement, then padded with 17 zeroes to a total length of 32 octets. The example below sends an
IPv4 address 192.168.1.253 as "`0xc0 0xa8 0x01 0xfd`" and the TCP port as 0x1b 0x58 (port 7000 = 0x1b58):
```
$ sudo hcitool -i hci0 cmd 0x08 0x0008 0x0e 0x0d 0xff 0x4c 0x00 0x09 0x08 0x13 0x30 0xc0 0xa8 0x01 0xfd 0x1b 0x58 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
< HCI Command: ogf 0x08, ocf 0x0008, plen 32
0E 0D FF 4C 00 09 08 13 30 C0 A8 01 FD 1B 58 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00
> HCI Event: 0x0e plen 4
01 08 20 00
```
**Step 3**. Start the beacon with a 1-byte message "`0x01`" = "on", sent with HCI LE command 0x000a = 10:
```
$ sudo hcitool -i hci0 cmd 0x08 0x000a 0x01
< HCI Command: ogf 0x08, ocf 0x000a, plen 1
01
> HCI Event: 0x0e plen 4
02 0A 20 00
```
The full length of the broadcasted beacon message is 46 bytes.
To stop the beacon, use this command to send the 1-byte message "`0x00`" = "off".
* For testing Bluetooth beacon Service Discovery on Linux, you will need to suppress the avahi-daemon which
provides DNS-SD Service Discovery on UxPlay's Host system (replace `mask` and ``stop`` below
by `unmask` and ``start`` to restore DNS-SD service):
If you wish to test Bluetooth LE Service Discovery on Linux/*BSD, you can disable DNS_SD Service discovery by the avahi-daemon with
```
$ sudo systemctl mask avahi-daemon.socket
$ sudo systemctl stop avahi-daemon
```
An automated procedure for creating the beacon would presumably want to switch it on when uxplay starts, and off when it
stops. It has the task of determing a host IPv4 address that the client can use to reach uxplay.
The 22-byte file created when uxplay starts (and deleted when it stops) contains the RAOP port as a uint16_t unsigned short,
in the first 2 bytes, followed by
the uxplay PID as a uint32_t unsigned integer in the next 4 bytes, then
followed by up to the first
15 characters of the process name (usually "uxplay") as a null-terminated string, padded with zeroes to 16 bytes. The port data
identifies the port on the Host that uxplay listens on, which should be included along with the Host IPv4 address
in the advertisement broadcast by the beacon. The path to this file is needed as the only input by the procedure when it is started.
The presence of the file should be checked at regular intervals (once per second?). If it is absent, uxplay has stopped running,
but if it exists the process ID and process name of that PID should be checked to handle cases where a new uxplay process has
started, or if uxplay has exited abnormally and failed to delete the file. (While it is probably not an important use case, the possibility of
concurrent uxplay processes listening on different ports and writing different files could be handled: the advertising protocol allows
cycling between different messages.)
To restore DNS_SD Service discovery, replace "mask" by "unmask", and "stop" by "start".
This method above creates a beacon that identifies itself with a "public Advertising Address" (the MAC hardware address of
the Bluetooth device). An Apple TV uses a private random address. If you wish to do that, change the sixth octet (the one following `0x03`)
in Step 1 from "TxAdd" = `0x00` to TxAdd = ``0x01``, and add an intermediate "step 1.5":
**Step 1.5** Choose 6 random bytes r1, r2, r3, r4, r5, r6, such as
"`0x52 0xaa, 0xaa, 0x3a, 0xb4, 0x2f`", and use HCI LE command 0x0005 to set the random address:
```
$sudo hcitool -i hci0 cmd 0x08 0x0005 0x52 0xaa 0xaa 0x3a 0xb4 0x2f
< HCI Command: ogf 0x08, ocf 0x0005, plen 6
52 AA AA 3A B4 2F
> HCI Event: 0x0e plen 4
02 05 20 00
```
On a Bluetooth packet sniffer with wireshark, this address displays as: **Advertising Address: 2f:b4:3a:aa:aa:52**.
In principle, random byte r6 should be masked with 0x03 (r6 = r6 | 0x03) to mark the address as a "static random private address",
but Apple TV does not do this. In fact it updates to a new random Advertising Address every 20 mins or so, increasing
the seed in the Apple Data by 1 each time. Apple TV's also add a length 2 type 0x01 ("Flags") Advertising PDU "`0x02 0x01 0x1a`" in front of
the main type 0xff "Manufacturer-Specific Data" Advertising PDU in Step 2. This is "optional" for ADV_NONCONN_IND advertisement type,
and testing shows that it can be dropped without affecting Service Discovery, which is fortunate
because the high-level Linux and Windows interfaces mentioned earlier do not permit users to send a "Flags"-type PDU.
For more information, see the [wiki page](https://github.com/FDH2/UxPlay/wiki/Bluetooth_LE_beacon)
This has useful information if you wish to build a python beacon controller script for Windows (we would like to have one!).
* **Our current understanding is that Bluetooth LE AirPlay Service Discovery only supports
broadcast of IPv4 addresses. Please let us know if this is incorrect, or if IPv6 support is introduced in the future.**

View File

@@ -9,12 +9,13 @@
beacon runs independently of UxPlay and regularly broadcasts a
Bluetooth LE ("Low Energy") 46 byte packet informing nearby
iOS/macOS devices of the local IPv4 network address of the UxPlay
server, and which TCP port to contact UxPlay on. Instructions for
manually setting up such a beacon in Linux are [given
below](#bluetooth-le-beacon-setup). **It is hoped that users will
submit Pull Requests contributing scripts for automating beacon
setup on all platforms. (Python may be an appropriate language
choice)**
server, and which TCP port to contact UxPlay on. A python script
(Python \>=3.6) "uxplay-beacon.py", to broadcast the
Service-Discovery advertisement will be installed on systems with
DBus support (Linux and \*BSD, using Bluez for Bluetooth control):
this does **not** require enhanced "root permissions" to run. A
windows version of this script is also planned for the future.
Instructions are [given below](#bluetooth-le-beacon-setup).
- **NEW on github**: option `-vrtp <rest-of-pipeline>` bypasses
rendering by UxPlay, and instead transmits rtp packets of decrypted
@@ -1478,11 +1479,12 @@ that (unlike dumped video) the dumped audio is currently only useful for
debugging, as it is not containerized to make it playable with standard
audio players.*
**-ble *filename***. Enable Bluetooth beacon Service Discovery. The PID
and process name of the UxPlay process is recorded in *filename*, which
must be the full path to a writeable file. (This file is created when
UxPlay starts and deleted when it stops.) **See below for beacon setup
instructions.**
**-ble \[*filename*\]**. Enable Bluetooth beacon Service Discovery. The
port, PID and process name of the UxPlay process is recorded by default
in `~/.uxplay.ble` : (this file is created when UxPlay starts and
deleted when it stops.) Optionally the file *filename*, which must be
the full path to a writeable file can instead be used. **See below for
beacon setup instructions.**
**-d \[n\]** Enable debug output; optional argument n=1 suppresses
audio/video packet data in debug output. Note: this does not show
@@ -1494,206 +1496,72 @@ this to see even more of the GStreamer inner workings.
# Bluetooth LE beacon setup
To allow UxPlay to work with Bluetooth Low Energy (LE) Service
Discovery, as an alternative to DNS-SD (Bonjour/Rendezvous) service
discovery, start it with the option "`-ble <path-to-writeable-file>`",
which at startup writes a data file containing the uxplay TCP port for
receiving replies to the advertisement, plus the uxplay process ID and
process name, and is deleted when uxplay terminates normally. **This
file is not used in the simple manual method for creating a beacon
described below**.
The python\>=3.6 script for running a Bluetooth-LE Service Discovery
beacon is uxplay-beacon.py. Currently only a DBus version (for Linux and
\*BSD) is available, and it is only installed on systems which support
DBus.
Bluetooth LE Service discovery uses a "beacon" broadcasting a simple
14-byte advertisement "`0D FF 4C 00 09 08 13 30 XX XX XX XX YY YY`"
where XX XX XX XX is an IPv4 internet address (and port YY YY) of the
UxPlay host translated into hexadecimal octets. For example,
"`XX XX XX XX YY YY`" = "`C0 A8 01 FD 1B 58`" means 192.168.1.253 port
0x1b58 (decimal value 7000). UxPlay must be able to receive messages on
this TCP port at this address. The uxplay option "`-p`" sets up uxplay
to listen on the default port 7000 for these messages, as used in the
example above. Otherwise the port in the beacon message should be the
first (`<n>`) of the 3 open TCP ports specified with uxplay option
`-p <n>`. If the `-p` option is not used (which is only possible if
there is no active firewall) the TCP port is selected at random, and its
value must be taken from the beginning of the file written with the
`-ble` option.
If uxplay will be run with option "`uxplay -ble`" (so it writes data for
the Bluetooth beacon in the default BLE data file `~/.uxplay.ble`), just
run `uxplay-beacon.py` in a separate terminal. The python script will
start Bluetooth LE Service-Discovery advertising when it detects that
UxPlay is running by checking if the BLE data file exists, and stop when
it no longer detects a running UxPlay plus this file (it will restart
advertising if UxPlay later reappears). The script will remain active
until stopped with Ctrl+C in its terminal window (or its terminal window
is closed).
The full translation of this message is that it has length 0D = 0x0d =
13 octets, and is a single "Advertising Protocol Data Unit" (PDU) of
type "`FF`", called "Manufacturer-Specific Data", with "manufacturer
code" "`4C 00`" = 0x004c = Apple (note the reversal of octet order when
two octets are combined to make a two-byte unsigned short integer), and
"`09 08 13 30 XX XX XX XX YY YY`" is the Apple-specific data.
The beacon script can be more finely controlled using five possible
options: these can be given on the command line, or read from a
configuration file `~/.uxplay.beacon`, if it exists. Configuration file
entries are like the command line forms, one per line (e.g.,
`--ipv4 192.168.1.100`). Lines commented out with an initial `#` are
ignored. Command line options override the configuration file options.
The Apple-specific data contains a single Apple Data Unit with Apple
type = 09 (Airplay), Apple Data length 08 (0x08 = 8 octets) and Apple
Data "`13 30 XX XX XX XX YY YY`" where 13 = 0001 0011 is Apple Flags, 30
is a seed (which will be ignored), XX XX XX XX is the IPv4 internet
address and YY YY is the port. This is smaller than the "iBeacon" Apple
Data Unit, which has Apple type 02 and Apple length 15 (0x15 = 21
octets).
- `--file <config file>` read beacon options from `<config file>`
instead of `~/.uxplay.beacon`.
In addition to creating the message, we need to set the "Advertising
type" (ADV_NONCONN_IND) and "Advertising interval" range \[AdvMin,
AdvMax\], where 0x00a0 = 100 msec \<= AdvMin \<= AdvMax \<= 0x4000 =
10.24 sec (intervals are given in units of 0.625 msec as uint16_t
unsigned short integers). Setting AdvMin = AdvMax fixes the interval;
AdvMin \< AdvMax allows the choice of the time of each advertising
broadcast to be flexible within an allowed window to avoid clashing with
other Bluetooth tasks. Keep the default choice to broadcast
simultaneously on all three advertising channels, 37,38,39.
- `--ipv4 <ipv4 address>`. This option can be used to specify the
ipv4 address at which the UxPlay server should be contacted by the
client. If it is not given, an address will be obtained
automatically using `gethostbyname`. Only ipv4 addresses are
supported.
An automated script to setup and start the beacon should use a
high-level interface such as: (Linux) Bluez
[LEAdvertisingManager1](https://manpages.opensuse.org/Leap-16.0/bluez/org.bluez.LEAdvertisement.5.en.html)
(with an
[example](https://github.com/bluez/bluez/blob/master/test/example-advertisement))
and (Windows 10/11)
[BluetoothLEAdvertisementPublisherClass](https://learn.microsoft.com/en-us/uwp/api/windows.devices.bluetooth.advertisement.bluetoothleadvertisementpublisher)
(with an
[example](https://github.com/MicrosoftDocs/windows-dev-docs/blob/docs/uwp/devices-sensors/ble-beacon.md)).
**We invite submission of Pull Requests for working implementations!**
- `--path <BLE data file>`. This overrides the default choice of BLE
data file (`~/.uxplay.ble`) that is monitored by the beacon script.
This also requires that uxplay is run with option
"`uxplay -ble <BLE data file>`".
Until automated scripts are available, a simple Linux-only low-level
manual method is given below, using the `hcitool` and `hciconfig`
utilities which directly access the HCI stack, and need elevated
privileges (use `sudo`). These utilities have been declared "deprecated"
and "obsolete" by BlueZ developers: on Debian-based Linux
"`sudo apt install bluez`" still provides `hcitool`, but on some other
Linux distributions, it is split off from the main BlueZ package into an
"extra" package with a name like "bluez-deprecated". If we get the
AirPlay beacon to work using the newer `bluetoothctl` or `btmgmt`
utilities, these instructions will be updated.
- `--AdvMin x`, `--AdvMax y`. These controls the interval between BLE
advertisement broadcasts. This interval is in the range \[x, y\],
given in units of msecs. Allowed ranges are 100 \<= x \<= y
\<= 10240. If AdvMin=AdvMax, the interval is fixed: if AdvMin \<
AdvMax it is chosen flexibly in this range to avoid interfering with
other tasks the Bluetooth device is carrying out. The default values
are AdvMin = AdvMax = 100. The advertisement is broadcast on all
three Bluetooth LE advertising channels: 37,38,39.
First verify that a Bluetooth HCI interface is available:
- `--index x` (default x = 0, x \>= 0). This should be used to
distinguish between multiple simultaneous instances of
uxplay-beacon.py that are running to support multiple instances of
UxPlay. Each instance must have its own BLE Data file (just as each
instance of UxPlay must also have its own MAC address and ports).
*Note: running multiple beacons simultaneously on the same host has
not been tested.*
$hcitool dev
Devices:
hci1 E8:EA:6A:7C:3F:CC
hci0 08:BE:AC:40:A9:DC
If you wish to test Bluetooth LE Service Discovery on Linux/\*BSD, you
can disable DNS_SD Service discovery by the avahi-daemon with
This shows two devices with their MAC addresses. You can use
"`hciconfig -a`" to see which versions of Bluetooth they implement: we
require Bluetooth v4.0 or later; you may need to use a cheap USB
Bluetooth dongle if your system does not have it, or will not let you
use it for LE (Low Energy) transmissions.\
Choose which interface to use (we will use hci0), and reset it.
$ sudo hciconfig hci0 reset
**Step 1.** Configure the beacon by sending a configure command 0x0006
to the Bluetooth LE stack 0x08. `hcitool` echoes the HCI command and the
4-byte "HCI Event" response. The only important part of the response is
that the last byte is "`00`" (= "success": other values are error
codes):
$ sudo hcitool -i hci0 cmd 0x08 0x0006 0xa0 0x00 0xa0 0x00 0x03 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x07 0x00
< HCI Command: ogf 0x08, ocf 0x0006, plen 15
A0 00 A0 00 03 00 00 00 00 00 00 00 00 07 00
> HCI Event: 0x0e plen 4
02 06 20 00
The first "`0xa0 0x00`" sets AdvMin = 0x00a0 = 100 msec. The second
"`0xa0 0x00`" sets AdvMax = 0x00a0 = 100 msec. Then "`0x03`" sets the
Advertising Type to ADV_NONCONN_IND. The other non-zero entry (0x07 =
0000 0111) is the flag for using all three advertising channels.
An Apple TV (Gen 3) seems to use AdvMin = AdvMax = 180 msec = 0x0120
("`0x20 0x01`").
**Step 2.** Set the advertising message with HCI LE command 0x0008. For
this command, hcitool requires a 32 octet message after
`sudo hcitool -i hci0 cmd 0x08 0x0008`: The first octet is the length 0E
= 0x0e = 14 of the "significant part" of the following 31 octets,
followed by the 14 octets of the advertisement, then padded with 17
zeroes to a total length of 32 octets. The example below sends an IPv4
address 192.168.1.253 as "`0xc0 0xa8 0x01 0xfd`" and the TCP port as
0x1b 0x58 (port 7000 = 0x1b58):
$ sudo hcitool -i hci0 cmd 0x08 0x0008 0x0e 0x0d 0xff 0x4c 0x00 0x09 0x08 0x13 0x30 0xc0 0xa8 0x01 0xfd 0x1b 0x58 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
< HCI Command: ogf 0x08, ocf 0x0008, plen 32
0E 0D FF 4C 00 09 08 13 30 C0 A8 01 FD 1B 58 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00
> HCI Event: 0x0e plen 4
01 08 20 00
**Step 3**. Start the beacon with a 1-byte message "`0x01`" = "on", sent
with HCI LE command 0x000a = 10:
$ sudo hcitool -i hci0 cmd 0x08 0x000a 0x01
< HCI Command: ogf 0x08, ocf 0x000a, plen 1
01
> HCI Event: 0x0e plen 4
02 0A 20 00
The full length of the broadcasted beacon message is 46 bytes. To stop
the beacon, use this command to send the 1-byte message "`0x00`" =
"off".
- For testing Bluetooth beacon Service Discovery on Linux, you will
need to suppress the avahi-daemon which provides DNS-SD Service
Discovery on UxPlay's Host system (replace `mask` and `stop` below
by `unmask` and `start` to restore DNS-SD service):
```{=html}
<!-- -->
```
$ sudo systemctl mask avahi-daemon.socket
$ sudo systemctl stop avahi-daemon
An automated procedure for creating the beacon would presumably want to
switch it on when uxplay starts, and off when it stops. It has the task
of determing a host IPv4 address that the client can use to reach
uxplay. The 22-byte file created when uxplay starts (and deleted when it
stops) contains the RAOP port as a uint16_t unsigned short, in the first
2 bytes, followed by the uxplay PID as a uint32_t unsigned integer in
the next 4 bytes, then followed by up to the first 15 characters of the
process name (usually "uxplay") as a null-terminated string, padded with
zeroes to 16 bytes. The port data identifies the port on the Host that
uxplay listens on, which should be included along with the Host IPv4
address in the advertisement broadcast by the beacon. The path to this
file is needed as the only input by the procedure when it is started.
The presence of the file should be checked at regular intervals (once
per second?). If it is absent, uxplay has stopped running, but if it
exists the process ID and process name of that PID should be checked to
handle cases where a new uxplay process has started, or if uxplay has
exited abnormally and failed to delete the file. (While it is probably
not an important use case, the possibility of concurrent uxplay
processes listening on different ports and writing different files could
be handled: the advertising protocol allows cycling between different
messages.)
To restore DNS_SD Service discovery, replace "mask" by "unmask", and
"stop" by "start".
This method above creates a beacon that identifies itself with a "public
Advertising Address" (the MAC hardware address of the Bluetooth device).
An Apple TV uses a private random address. If you wish to do that,
change the sixth octet (the one following `0x03`) in Step 1 from "TxAdd"
= `0x00` to TxAdd = `0x01`, and add an intermediate "step 1.5":
**Step 1.5** Choose 6 random bytes r1, r2, r3, r4, r5, r6, such as
"`0x52 0xaa, 0xaa, 0x3a, 0xb4, 0x2f`", and use HCI LE command 0x0005 to
set the random address:
$sudo hcitool -i hci0 cmd 0x08 0x0005 0x52 0xaa 0xaa 0x3a 0xb4 0x2f
< HCI Command: ogf 0x08, ocf 0x0005, plen 6
52 AA AA 3A B4 2F
> HCI Event: 0x0e plen 4
02 05 20 00
On a Bluetooth packet sniffer with wireshark, this address displays as:
**Advertising Address: 2f:b4:3a:aa:aa:52**. In principle, random byte r6
should be masked with 0x03 (r6 = r6 \| 0x03) to mark the address as a
"static random private address", but Apple TV does not do this. In fact
it updates to a new random Advertising Address every 20 mins or so,
increasing the seed in the Apple Data by 1 each time. Apple TV's also
add a length 2 type 0x01 ("Flags") Advertising PDU "`0x02 0x01 0x1a`" in
front of the main type 0xff "Manufacturer-Specific Data" Advertising PDU
in Step 2. This is "optional" for ADV_NONCONN_IND advertisement type,
and testing shows that it can be dropped without affecting Service
Discovery, which is fortunate because the high-level Linux and Windows
interfaces mentioned earlier do not permit users to send a "Flags"-type
PDU.
For more information, see the [wiki
page](https://github.com/FDH2/UxPlay/wiki/Bluetooth_LE_beacon) This has
useful information if you wish to build a python beacon controller
script for Windows (we would like to have one!).
- **Our current understanding is that Bluetooth LE AirPlay Service
Discovery only supports broadcast of IPv4 addresses. Please let us

45
uxplay-beacon.1 Normal file
View File

@@ -0,0 +1,45 @@
.TH UXPLAY 1 2025-10-26 "UxPlay 1.72" "User Commands"
.SH NAME
uxplay-beacon.py \- Python (>= 3.6) script for a Bluetooth LE Service-Discovery beacon.
.SH SYNOPSIS
.B uxplay-beacon.py
[\fI\, -h, --help] + more options.
.SH DESCRIPTION
UxPlay 1.72: Standalone Python Script for managing Bluetooth LE Service Discovery.
.SH OPTIONS
.TP
.B
\fB\--file\fR fn Specify alternate configuration file
.TP
\fB\--path\fR fn Specify non-default Bluetooth LE data file used by uxplay
.TP
\fB\--ipv4\fR ip Override automatically-found ipv4 address for contacting UxPlay
.TP
\fB\--AdvMin\fR x Minimum Advertising interval in msecs (>= 100)
.TP
\fB\--AdvMin\fR y Maximum Advertising interval in msecs (>= AdvMin, <= 102400)
.TP
\fB\--index\fR x Used to distinguish different instances of beacons
.TP
\fB \-h, --help\fR Show help text.
.SH
FILES
Options in beacon configuration file ~/.uxplay.beacon
.TP
are applied first (command-line options may modify them). Format:
.TP
one option per line, with initial "--"; lines beginning with "#" ignored.
.SH
AUTHORS
.TP
Various, see website or distribution.
.SH
COPYRIGHT
.TP
Various, see website or distribution. License: GPL v3+:
.TP
GNU GPL version 3 or later. (some parts LGPL v.2.1+ or MIT).
.SH
SEE ALSO
.TP
Website: <https://github.com/FDH2/UxPlay>

View File

@@ -1,4 +1,4 @@
.TH UXPLAY "1" "May 2025" "1.72" "User Commands"
.TH UXPLAY "1" "2025-10-26" "UxPlay 1.72" "User Commands"
.SH NAME
uxplay \- start AirPlay server
.SH SYNOPSIS
@@ -191,7 +191,9 @@ UxPlay 1.72: An open\-source AirPlay mirroring (+ audio streaming) server:
audio packets are dumped. "aud"= unknown format.
.PP
.TP
\fB\-ble\fI fn\fR For BluetoothLE beacon: write PID to file fn ("off" to cancel)
\fB\-ble\fI [fn]\fR For BluetoothLE beacon: write data to default file ~/.uxplay.ble
.IP
optional: write to file "fn" ("fn" = "off" to cancel)
.TP
\fB\-d [n]\fR Enable debug logging; optional: n=1 to skip normal packet data.
.TP

View File

@@ -924,7 +924,8 @@ static void print_info (char *name) {
printf(" =1,2,..; fn=\"audiodump\"; change with \"-admp [n] filename\".\n");
printf(" x increases when audio format changes. If n is given, <= n\n");
printf(" audio packets are dumped. \"aud\"= unknown format.\n");
printf("-ble fn For BluetoothLE beacon: write PID to file fn (\"off\" to cancel)\n");
printf("-ble [fn] For BluetoothLE beacon: write data to file ~/.uxplay.ble\n");
printf(" optional: write to file \"fn\" (\"fn\" = \"off\" to cancel)\n");
printf("-d [n] Enable debug logging; optional: n=1 to skip normal packet data\n");
printf("-v Displays version information\n");
printf("-h Displays this help\n");
@@ -1386,8 +1387,8 @@ static void parse_arguments (int argc, char *argv[]) {
exit(1);
}
} else if (arg == "-ble" ) {
if (option_has_value(i, argc, arg, argv[i+1])) {
ble_filename.erase();
if (i < argc - 1 && *argv[i+1] != '-') {
i++;
if (strlen(argv[i]) != 3 || strncmp(argv[i], "off", 3)) {
ble_filename.append(argv[i]);
@@ -1397,9 +1398,19 @@ static void parse_arguments (int argc, char *argv[]) {
}
}
} else {
fprintf(stderr,"option -ble must be followed by a filename for PID data or by \"off\"\n");
static const char* homedir = get_homedir();
if (homedir) {
ble_filename = homedir;
ble_filename.append("/.uxplay.ble");
if (!file_has_write_access(ble_filename.c_str())) {
fprintf(stderr, "%s cannot be written to\n",ble_filename.c_str()) ;
exit(1);
}
} else {
fprintf(stderr,"failed to obtain home directory\n");
exit(1);
}
}
} else if (arg == "-bt709") {
bt709_fix = true;
} else if (arg == "-srgb") {