# Copyright (c) 2013 Cortney T. Buffington, N0MJS n0mjs@me.com # # This work is licensed under the Creative Commons Attribution-ShareAlike # 3.0 Unported License.To view a copy of this license, visit # http://creativecommons.org/licenses/by-sa/3.0/ or send a letter to # Creative Commons, 444 Castro Street, Suite 900, Mountain View, # California, 94041, USA. from __future__ import print_function from twisted.internet.protocol import DatagramProtocol from twisted.internet import reactor from twisted.internet import task import sys import argparse import binascii import hmac import hashlib import socket #from logging.config import dictConfig #import logging #************************************************ # IMPORTING OTHER FILES - '#include' #************************************************ # Import system logger configuration # try: from ipsc_logger import logger except ImportError: sys.exit('System logger configuraiton not found or invalid') # Import configuration and informational data structures # try: from my_ipsc_config import NETWORK except ImportError: sys.exit('Configuration file not found, or not valid formatting') # Import IPSC message types and version information # try: from ipsc_message_types import * except ImportError: sys.exit('IPSC message types file not found or invalid') # Import IPSC flag mask values # try: from ipsc_mask import * except ImportError: sys.exit('IPSC mask values file not found or invalid') #************************************************ # GLOBALLY SCOPED FUNCTIONS #************************************************ # Remove the hash from a paket and return the payload # def strip_hash(_data): return _data[:-10] # Determine if the provided peer ID is valid for the provided network # def valid_peer(_peer_list, _peerid): if _peerid in _peer_list: return True return False # Determine if the provided master ID is valid for the provided network # def valid_master(_network, _peerid): if NETWORK[_network]['MASTER']['RADIO_ID'] == _peerid: return True else: return False # Take a packet to be SENT, calcualte auth hash and return the whole thing # def hashed_packet(_key, _data): hash = binascii.a2b_hex((hmac.new(_key,_data,hashlib.sha1)).hexdigest()[:20]) return (_data + hash) # Take a RECEIVED packet, calculate the auth hash and verify authenticity # def validate_auth(_key, _data): _log = logger.debug _payload = _data[:-10] _hash = _data[-10:] _chk_hash = binascii.a2b_hex((hmac.new(_key,_payload,hashlib.sha1)).hexdigest()[:20]) if _chk_hash == _hash: _log(' AUTH: Valid - Payload: %s, Hash: %s', binascii.b2a_hex(_payload), binascii.b2a_hex(_hash)) return True else: _log(' AUTH: Invalid - Payload: %s, Hash: %s', binascii.b2a_hex(_payload), binascii.b2a_hex(_hash)) return False # Forward Group Voice Packet # def fwd_group_voice(_network, _data): _src_group = _data[9:12] _src_ipsc = _data[1:5] for source in NETWORK[_network]['RULES']['GROUP_VOICE']: if source['SRC_GROUP'] == _src_group: _target = source['DST_NET'] _target_sock = NETWORK[_target]['MASTER']['IP'], NETWORK[_target]['MASTER']['PORT'] _data = _data.replace(_src_ipsc, NETWORK[_target]['LOCAL']['RADIO_ID']) _data = _data.replace(_src_group, source['DST_GROUP']) _data = hashed_packet(NETWORK[_target]['LOCAL']['AUTH_KEY'], _data) networks[_target].transport.write(_data, (_target_sock)) # Take a recieved peer list and the network it belongs to, process and populate the # data structure in my_ipsc_config with the results. # def process_peer_list(_data, _network, _peer_list): _log = logger.debug NETWORK[_network]['MASTER']['STATUS']['PEER-LIST'] = True _num_peers = int(str(int(binascii.b2a_hex(_data[5:7]), 16))[1:]) NETWORK[_network]['LOCAL']['NUM_PEERS'] = _num_peers _log('<<- (%s) The Peer List has been Received from Master\n%s \ There are %s peers in this IPSC Network', _network, (' '*(len(_network)+7)), _num_peers) for i in range(7, (_num_peers*11)+7, 11): hex_radio_id = (_data[i:i+4]) hex_address = (_data[i+4:i+8]) hex_port = (_data[i+8:i+10]) hex_mode = (_data[i+10:i+11]) decoded_mode = mode_decode(hex_mode, _data) if hex_radio_id not in _peer_list: _peer_list.append(hex_radio_id) NETWORK[_network]['PEERS'].append({ 'RADIO_ID': hex_radio_id, 'IP': socket.inet_ntoa(hex_address), 'PORT': int(binascii.b2a_hex(hex_port), 16), 'MODE': hex_mode, 'PEER_OPER': decoded_mode[0], 'PEER_MODE': decoded_mode[1], 'TS1_LINK': decoded_mode[2], 'TS2_LINK': decoded_mode[3], 'STATUS': {'CONNECTED': False, 'KEEP_ALIVES_SENT': 0, 'KEEP_ALIVES_MISSED': 0, 'KEEP_ALIVES_OUTSTANDING': 0} }) return _peer_list # Given a mode byte, decode the functions and return a tuple of results # def mode_decode(_mode, _data): _log = logger.debug _mode = int(binascii.b2a_hex(_mode), 16) link_op = _mode & PEER_OP_MSK link_mode = _mode & PEER_MODE_MSK ts1 = _mode & IPSC_TS1_MSK ts2 = _mode & IPSC_TS2_MSK # Determine whether or not the peer is operational if link_op == 0b01000000: _peer_op = True elif link_op == 0b00000000: _peer_op = False else: _peer_op = False # Determine the operational mode of the peer if link_mode == 0b00000000: _peer_mode = 'NO_RADIO' elif link_mode == 0b00010000: _peer_mode = 'ANALOG' elif link_mode == 0b00100000: _peer_mode = 'DIGITAL' else: _peer_node = 'NO_RADIO' # Determine whether or not timeslot 1 is linked if ts1 == 0b00001000: _ts1 = True else: _ts1 = False # Determine whether or not timeslot 2 is linked if ts2 == 0b00000010: _ts2 = True else: _ts2 = False # Return a tuple with the decoded values return _peer_op, _peer_mode, _ts1, _ts2 # Gratuituous print-out of the peer list.. Pretty much debug stuff. # def print_peer_list(_network): _log = logger.info # os.system('clear') if not NETWORK[_network]['PEERS']: print('No peer list for: {}' .format(_network)) return print('Peer List for: %s' % _network) for dictionary in NETWORK[_network]['PEERS']: if dictionary['RADIO_ID'] == NETWORK[_network]['LOCAL']['RADIO_ID']: me = '(self)' else: me = '' print('\tRADIO ID: {} {}' .format(int(binascii.b2a_hex(dictionary['RADIO_ID']), 16), me)) print('\t\tIP Address: {}:{}' .format(dictionary['IP'], dictionary['PORT'])) print('\t\tOperational: {}, Mode: {}, TS1 Link: {}, TS2 Link: {}' .format(dictionary['PEER_OPER'], dictionary['PEER_MODE'], dictionary['TS1_LINK'], dictionary['TS2_LINK'])) print('\t\tStatus: {}, KeepAlives Sent: {}, KeepAlives Outstanding: {}, KeepAlives Missed: {}' .format(dictionary['STATUS']['CONNECTED'], dictionary['STATUS']['KEEP_ALIVES_SENT'], dictionary['STATUS']['KEEP_ALIVES_OUTSTANDING'], dictionary['STATUS']['KEEP_ALIVES_MISSED'])) print('') #************************************************ #******** *********** #******** IPSC Network 'Engine' *********** #******** *********** #************************************************ #************************************************ # INITIAL SETUP of IPSC INSTANCE #************************************************ class IPSC(DatagramProtocol): # Modify the initializer to set up our environment and build the packets # we need to maitain connections # def __init__(self, *args, **kwargs): if len(args) == 1: # Housekeeping: create references to the configuration and status data for this IPSC instance. # Some configuration objects that are used frequently and have lengthy names are shortened # such as (self._master_sock) expands to (self._config['MASTER']['IP'], self._config['MASTER']['PORT']) # self._network = args[0] self._config = NETWORK[self._network] # self._local = self._config['LOCAL'] self._local_stat = self._local['STATUS'] self._local_id = self._local['RADIO_ID'] # self._master = self._config['MASTER'] self._master_stat = self._master['STATUS'] self._master_sock = self._master['IP'], self._master['PORT'] # self._peers = self._config['PEERS'] # # This is a regular list to store peers for the IPSC. At times, parsing a simple list is much less # Spendy than iterating a list of dictionaries... Maybe I'll find a better way in the future. Also # We have to know when we have a new peer list, so a variable to indicate we do (or don't) # self._peer_list = [] self._peer_list_new = False args = () # Packet 'constructors' - builds the necessary control packets for this IPSC instance # self.TS_FLAGS = (self._local['MODE'] + self._local['FLAGS']) self.MASTER_REG_REQ_PKT = (MASTER_REG_REQ + self._local_id + self.TS_FLAGS + IPSC_VER) self.MASTER_ALIVE_PKT = (MASTER_ALIVE_REQ + self._local_id + self.TS_FLAGS + IPSC_VER) self.PEER_LIST_REQ_PKT = (PEER_LIST_REQ + self._local_id) self.PEER_REG_REQ_PKT = (PEER_REG_REQ + self._local_id + IPSC_VER) self.PEER_REG_REPLY_PKT = (PEER_REG_REPLY + self._local_id + IPSC_VER) self.PEER_ALIVE_REQ_PKT = (PEER_ALIVE_REQ + self._local_id + self.TS_FLAGS) self.PEER_ALIVE_REPLY_PKT = (PEER_ALIVE_REPLY + self._local_id + self.TS_FLAGS) else: # If we didn't get called correctly, log it! # logger.error('(%s) Unexpected arguments found.', self._network) # This is called by REACTOR when it starts, We use it to set up the timed # loop for each instance of the IPSC engine # def startProtocol(self): # Timed loop for IPSC connection establishment and maintenance # Others could be added later for things like updating a Web # page, etc.... # self._call = task.LoopingCall(self.timed_loop) self._loop = self._call.start(self._local['ALIVE_TIMER']) #************************************************ # FUNCTIONS FOR IPSC Network Engine #************************************************ #************************************************ # TIMED LOOP - MY CONNECTION MAINTENANCE #************************************************ def timed_loop(self): print_peer_list(self._network) if (self._master_stat['CONNECTED'] == False): reg_packet = hashed_packet(self._local['AUTH_KEY'], self.MASTER_REG_REQ_PKT) self.transport.write(reg_packet, (self._master_sock)) elif (self._master_stat['CONNECTED'] == True): master_alive_packet = hashed_packet(self._local['AUTH_KEY'], self.MASTER_ALIVE_PKT) self.transport.write(master_alive_packet, (self._master_sock)) if (self._master_stat['KEEP_ALIVES_OUTSTANDING']) > 0: self._master_stat['KEEP_ALIVES_MISSED'] += 1 if self._master_stat['KEEP_ALIVES_OUTSTANDING'] >= self._local['MAX_MISSED']: self._master_stat['CONNECTED'] = False logger.error('Maximum Master Keep-Alives Missed -- De-registering the Master') self._master_stat['KEEP_ALIVES_SENT'] += 1 self._master_stat['KEEP_ALIVES_OUTSTANDING'] += 1 else: logger.error('->> (%s) Master in UNKOWN STATE:%s:%s', self._network, self._master_sock) if ((self._master_stat['CONNECTED'] == True) and (self._master_stat['PEER-LIST'] == False)): peer_list_req_packet = hashed_packet(self._local['AUTH_KEY'], self.PEER_LIST_REQ_PKT) self.transport.write(peer_list_req_packet, (self._master_sock)) if (self._master_stat['PEER-LIST'] == True): for peer in (self._peers): if (peer['RADIO_ID'] == self._local_id): # We are in the peer-list, but don't need to talk to ourselves continue if peer['STATUS']['CONNECTED'] == False: peer_reg_packet = hashed_packet(self._local['AUTH_KEY'], self.PEER_REG_REQ_PKT) self.transport.write(peer_reg_packet, (peer['IP'], peer['PORT'])) elif peer['STATUS']['CONNECTED'] == True: peer_alive_req_packet = hashed_packet(self._local['AUTH_KEY'], self.PEER_ALIVE_REQ_PKT) self.transport.write(peer_alive_req_packet, (peer['IP'], peer['PORT'])) if peer['STATUS']['KEEP_ALIVES_OUTSTANDING'] > 0: peer['STATUS']['KEEP_ALIVES_MISSED'] += 1 if peer['STATUS']['KEEP_ALIVES_OUTSTANDING'] >= self._local['MAX_MISSED']: peer['STATUS']['CONNECTED'] = False self._peer_list.remove(peer['RADIO_ID']) # Remove the peer from the simple list FIRST self._peers.remove(peer) # Becuase once it's out of the dictionary, you can't use it for anything else. logger.error('Maximum Peer Keep-Alives Missed -- De-registering the Peer: %s', peer) peer['STATUS']['KEEP_ALIVES_SENT'] += 1 peer['STATUS']['KEEP_ALIVES_OUTSTANDING'] += 1 #************************************************ # RECEIVED DATAGRAM - ACT IMMEDIATELY!!! #************************************************ # Actions for recieved packets by type: Call a function or process here... # def datagramReceived(self, data, (host, port)): _packettype = data[0:1] _peerid = data[1:5] _dec_peerid = int(binascii.b2a_hex(_peerid), 16) # First action: if Authentication is active, authenticate the packet # if bool(self._local['AUTH_KEY']) == True: if validate_auth(self._local['AUTH_KEY'], data) == False: logger.warning('(%s) AuthError: IPSC packet failed authentication. Type %s: Peer ID: %s', self._network, binascii.b2a_hex(_packettype), _dec_peerid) return data = strip_hash(data) # Packets generated by "users" that are the most common should come first for efficiency. # if (_packettype == GROUP_VOICE): if not(valid_master(self._network, _peerid) == False or valid_peer(self._peer_list, _peerid) == False): logger.warning('(%s) PeerError: Peer not in peer-list: %s', self._network, _dec_peerid) return fwd_group_voice(self._network, data) # IPSC keep alives, master and peer, come next in processing priority # elif (_packettype == PEER_ALIVE_REQ): if valid_peer(self._peer_list, _peerid) == False: logger.warning('(%s) PeerError: Peer %s not in peer-list: %s', self._network, _dec_peerid, self._peer_list) return peer_alive_reply_packet = hashed_packet(self._local['AUTH_KEY'], self.PEER_ALIVE_REPLY_PKT) self.transport.write(peer_alive_reply_packet, (host, port)) elif (_packettype == MASTER_ALIVE_REPLY): if valid_master(self._network, _peerid) == False: logger.warning('(%s) PeerError: Peer %s not in peer-list: %s', self._network, _dec_peerid, self._peer_list) return logger.debug('<<- (%s) Master Keep-alive Reply From: %s \t@ IP: %s:%s', self._network, _dec_peerid, host, port) self._master_stat['KEEP_ALIVES_OUTSTANDING'] = 0 elif (_packettype == PEER_ALIVE_REPLY): for peer in self._config['PEERS']: if peer['RADIO_ID'] == _peerid: peer['STATUS']['KEEP_ALIVES_OUTSTANDING'] = 0 # Registration requests and replies are infrequent, but important. Peer lists can go here too as a part # of the registration process. # elif (_packettype == MASTER_REG_REQ): logger.debug('<<- (%s) Master Registration Packet Recieved', self._network) elif (_packettype == MASTER_REG_REPLY): self._master['RADIO_ID'] = _peerid self._master_stat['CONNECTED'] = True self._master_stat['KEEP_ALIVES_OUTSTANDING'] = 0 elif (_packettype == PEER_REG_REQ): peer_reg_reply_packet = hashed_packet(self._local['AUTH_KEY'], self.PEER_REG_REPLY_PKT) self.transport.write(peer_reg_reply_packet, (host, port)) elif (_packettype == PEER_REG_REPLY): for peer in self._config['PEERS']: if peer['RADIO_ID'] == _peerid: peer['STATUS']['CONNECTED'] = True elif (_packettype == PEER_LIST_REPLY): self._peer_list = process_peer_list(data, self._network, self._peer_list) # Other "user" related packet types that we don't do much or anything with yet # elif (_packettype == PVT_VOICE): logger.warning('<<- (%s) Voice Packet From:%s:%s', self._network, host, port) elif (_packettype == GROUP_DATA): logger.warning('<<- (%s) Group Data Packet From:%s:%s', self._network, host, port) elif (_packettype == PVT_DATA): logger.warning('<<- (%s) Private Data Packet From From:%s:%s', self._network, host, port) elif (_packettype == DE_REG_REQ): logger.warning('<<- (%s) Peer De-Registration Request From:%s:%s', self._network, host, port) elif (_packettype == DE_REG_REPLY): logger.warning('<<- (%s) Peer De-Registration Reply From:%s:%s', self._network, host, port) elif (_packettype == RPT_WAKE_UP): logger.warning('<<- (%s) Repeater Wake-Up Packet From:%s:%s', self._network, host, port) # Technically, we're not paying any attention to these types because we're not part of the XCMP call control structure # elif (_packettype == XCMP_XNL): logger.warning('<<- (%s) XCMP_XNL From:%s:%s, but we did not indicate XCMP capable!', self._network, host, port) elif (_packettype in (CALL_CTL_1, CALL_CTL_2, CALL_CTL_3)): logger.warning('<<- (%s) Call Control Packet From:%s:%s', self._network, host, port) # If there's a packet type we don't know aobut, it should be logged so we can figure it out and take an appropriate action! else: packet_type = binascii.b2a_hex(_packettype) logger.error('<<- (%s) Received Unprocessed Type %s From:%s:%s', self._network, packet_type, host, port) #************************************************ # MAIN PROGRAM LOOP STARTS HERE #************************************************ if __name__ == '__main__': networks = {} for ipsc_network in NETWORK: networks[ipsc_network] = IPSC(ipsc_network) if (NETWORK[ipsc_network]['LOCAL']['ENABLED']): reactor.listenUDP(NETWORK[ipsc_network]['LOCAL']['PORT'], networks[ipsc_network]) reactor.run()