tvhProxyControl.py

from io import StringIO
import argparse
import os
import socket
import struct
import array
############################################################
# CRC
############################################################


crc32c_table = (
	0x00000000, 0x77073096, 0xee0e612c, 0x990951ba,
	0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3,
	0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
	0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91,
	0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de,
	0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
	0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec,
	0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5,
	0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
	0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,
	0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940,
	0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
	0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116,
	0x21b4f4b5, 0x56b3c423, 0xcfba9599, 0xb8bda50f,
	0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
	0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d,
	0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a,
	0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
	0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818,
	0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01,
	0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
	0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457,
	0x65b0d9c6, 0x12b7e950, 0x8bbeb8ea, 0xfcb9887c,
	0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
	0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2,
	0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb,
	0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
	0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9,
	0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086,
	0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
	0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4,
	0x59b33d17, 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad,
	0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
	0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683,
	0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8,
	0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
	0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe,
	0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7,
	0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
	0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5,
	0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252,
	0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
	0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60,
	0xdf60efc3, 0xa867df55, 0x316e8eef, 0x4669be79,
	0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
	0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f,
	0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04,
	0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
	0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a,
	0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713,
	0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
	0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21,
	0x86d3d2d4, 0xf1d4e242, 0x68ddb3f8, 0x1fda836e,
	0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
	0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c,
	0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45,
	0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
	0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db,
	0xaed16a4a, 0xd9d65adc, 0x40df0b66, 0x37d83bf0,
	0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
	0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6,
	0xbad03605, 0xcdd70693, 0x54de5729, 0x23d967bf,
	0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
	0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d,
)

def add(crc, buf):
	buf = array.array('B', buf)
	for b in buf:
		crc = (crc >> 8) ^ crc32c_table[(crc ^ b) & 0xff]
	return crc

def done(crc):
	tmp = ~crc & 0xffffffff
	b0 = tmp & 0xff
	b1 = (tmp >> 8) & 0xff
	b2 = (tmp >> 16) & 0xff
	b3 = (tmp >> 24) & 0xff
	crc = (b0 << 24) | (b1 << 16) | (b2 << 8) | b3
	return crc

def cksum(buf):
	"""Return computed CRC-32c checksum."""
	return done(add(0xffffffff, buf))
HDHOMERUN_DISCOVER_UDP_PORT = 65001
HDHOMERUN_CONTROL_TCP_PORT = 65001
HDHOMERUN_MAX_PACKET_SIZE = 1460
HDHOMERUN_MAX_PAYLOAD_SIZE = 1452

HDHOMERUN_TYPE_DISCOVER_REQ = 0x0002
HDHOMERUN_TYPE_DISCOVER_RPY = 0x0003
HDHOMERUN_TYPE_GETSET_REQ = 0x0004
HDHOMERUN_TYPE_GETSET_RPY = 0x0005
HDHOMERUN_TAG_DEVICE_TYPE = 0x01
HDHOMERUN_TAG_DEVICE_ID = 0x02
HDHOMERUN_TAG_GETSET_NAME = 0x03
HDHOMERUN_TAG_GETSET_VALUE = 0x04
HDHOMERUN_TAG_GETSET_LOCKKEY = 0x15
HDHOMERUN_TAG_ERROR_MESSAGE = 0x05
HDHOMERUN_TAG_TUNER_COUNT = 0x10
HDHOMERUN_TAG_DEVICE_AUTH_BIN = 0x29
HDHOMERUN_TAG_BASE_URL = 0x2A
HDHOMERUN_TAG_DEVICE_AUTH_STR = 0x2B

HDHOMERUN_DEVICE_TYPE_WILDCARD = 0xFFFFFFFF
HDHOMERUN_DEVICE_TYPE_TUNER = 0x00000001
HDHOMERUN_DEVICE_ID_WILDCARD = 0xFFFFFFFF

ignorelist = ['192.168.1.4'] # the tvheadend ip address(es), tvheadend crashes when it discovers the tvhproxy (TODO: Fix this)
SERVER_HOST = 'http://192.168.1.3:80'
LISTEN_IP = '192.168.1.3'

def retrieveTypeAndPayload(packet):
	header = packet[:4]
	checksum = packet[-4:]
	payload = packet[4:-4]

	packetType, payloadLength = struct.unpack('>HH',header)
	if payloadLength != len(payload):
		print('Bad packet payload length')
		return False

	if checksum != struct.pack('>I', cksum(header + payload)):
		print('Bad checksum')
		return False

	return (packetType, payload)

def createPacket(packetType, payload):
	header = struct.pack('>HH', packetType, len(payload))
	data = header + payload
	checksum = cksum(data)
	packet = data + struct.pack('>I', checksum)

	return packet

def processPacket(packet, client, logPrefix = ''):
	packetType, requestPayload = retrieveTypeAndPayload(packet)

	if packetType == HDHOMERUN_TYPE_DISCOVER_REQ:
		print('Discovery request received from ' + client[0])
		responsePayload = struct.pack('>BBI', HDHOMERUN_TAG_DEVICE_TYPE, 0x04, HDHOMERUN_DEVICE_TYPE_TUNER) #Device Type Filter (tuner)
		responsePayload += struct.pack('>BBI', HDHOMERUN_TAG_DEVICE_ID, 0x04, int('12345678', 16)) #Device ID Filter (any)
		responsePayload += struct.pack('>BB', HDHOMERUN_TAG_GETSET_NAME, len(SERVER_HOST)) + str.encode(SERVER_HOST) #Device ID Filter (any)
		responsePayload += struct.pack('>BBB', HDHOMERUN_TAG_TUNER_COUNT, 0x01, 6) #Device ID Filter (any)
		print(responsePayload)
		return createPacket(HDHOMERUN_TYPE_DISCOVER_RPY, responsePayload)

	# TODO: Implement request types
	if packetType == HDHOMERUN_TYPE_GETSET_REQ:
		print('Get set request received from ' + client[0])
		getSetName = None
		getSetValue = None
		payloadIO = StringIO(requestPayload)
		while True:
			header = payloadIO.read(2)
			if not header: break
			tag, length = struct.unpack('>BB',header)
			# TODO: If the length is larger than 127 the following bit is also needed to determine length
			if length > 127:
				print('Unable to determine tag length, the correct way to determine a length larger than 127 must still be implemented.')
				return False
			# TODO: Implement other tags
			if tag == HDHOMERUN_TAG_GETSET_NAME:
				getSetName = struct.unpack('>{0}s'.format(length),payloadIO.read(length))[0]
			if tag == HDHOMERUN_TAG_GETSET_VALUE:
				getSetValue = struct.unpack('>{0}s'.format(length),payloadIO.read(length))[0]

		if getSetName is None:
			return False
		else:
			responsePayload = struct.pack('>BB{0}s'.format(len(getSetName)), HDHOMERUN_TAG_GETSET_NAME, len(getSetName), getSetName)

			if getSetValue is not None:
				responsePayload += struct.pack('>BB{0}s'.format(len(getSetValue)), HDHOMERUN_TAG_GETSET_VALUE, len(getSetValue), getSetValue)

			return createPacket(HDHOMERUN_TYPE_GETSET_RPY, responsePayload)

	return False

def tcpServer():
	logPrefix = 'TCP Server - '
	print('Starting tcp server')
	controlSocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
	controlSocket.bind((LISTEN_IP, HDHOMERUN_CONTROL_TCP_PORT))
	controlSocket.listen(1)

	print('Listening...')
	try:
		while True:
			connection, client = controlSocket.accept()
			try:
				packet = connection.recv(HDHOMERUN_MAX_PACKET_SIZE)
				if not packet:
					print('No packet received')
					break
				if client[0] not in ignorelist:
					responsePacket = processPacket(packet, client)
					if responsePacket:
						print('Sending control reply over tcp')
						connection.send(responsePacket)
					else:
						print('No known control request received, nothing to send to client')
				else:
					print('Ignoring tcp client %s' % client[0])
			finally:
				connection.close()
	except:
		print('Exception occured')

	print('Stopping server')
	controlSocket.close()

def udpServer():
	logPrefix = 'UDP Server - '
	print('Starting udp server')
	discoverySocket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
	discoverySocket.bind(('0.0.0.0', HDHOMERUN_DISCOVER_UDP_PORT))
	print('Listening...')
	while True:
		packet, client = discoverySocket.recvfrom(HDHOMERUN_MAX_PACKET_SIZE)
		if not packet:
			print('No packet received')
			break
		if client[0] not in ignorelist:
			responsePacket = processPacket(packet, client)
			if responsePacket:
				print('Sending discovery reply over udp')
				discoverySocket.sendto(responsePacket, client)
			else:
				print('No discovery request received, nothing to send to client')
		else:
			print('Ignoring udp client %s' % client[0])

	discoverySocket.close()


if __name__ == '__main__':

	try:
		udpServer()
	except KeyboardInterrupt:
		exit(0)