# 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 #************************************************ # IMPORTING OTHER FILES - '#include' #************************************************ # Import system logger configuration # try: from ipsc.ipsc_logger import logger except ImportError: sys.exit('System logger configuration not found or invalid') # Import configuration and informational data structures # try: from ipsc.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.ipsc_message_types import * except ImportError: sys.exit('IPSC message types file not found or invalid') # Import IPSC flag mask values # try: from ipsc.ipsc_mask import * except ImportError: sys.exit('IPSC mask values file not found or invalid') #************************************************ # CALLBACK FUNCTIONS FOR USER PACKET TYPES #************************************************ def call_ctl_1(): pass def call_ctl_2(): pass def call_ctl_3(): pass def xcmp_xnl(): pass def group_voice(): # _log = logger.debug _src_group = _data[9:12] _src_ipsc = _data[1:5] for source in NETWORK[_network]['RULES']['GROUP_VOICE']: # Matching for rules is against the Destination Group in the SOURCE packet (SRC_GROUP) if source['SRC_GROUP'] == _src_group: _target = source['DST_NET'] _target_sock = NETWORK[_target]['MASTER']['IP'], NETWORK[_target]['MASTER']['PORT'] # Re-Write the IPSC SRC to match the target network's ID _data = _data.replace(_src_ipsc, NETWORK[_target]['LOCAL']['RADIO_ID']) # Re-Write the destinaion Group ID _data = _data.replace(_src_group, source['DST_GROUP']) # Calculate and append the authentication hash for the target network... if necessary if NETWORK[_target]['LOCAL']['AUTH_KEY'] == True: _data = hashed_packet(NETWORK[_target]['LOCAL']['AUTH_KEY'], _data) # Send the packet to all peers in the target IPSC send_to_ipsc(_target, _data) def private_voice(): pass def group_data(): pass def private_data(): pass def unknown_message(): pass #************************************************ # UTILITY FUNCTIONS FOR INTERNAL USE #************************************************ # Remove the hash from a paket and return the payload # def strip_hash(_data): # _log = logger.debug # _log('Stripped Packet: %s', binascii.b2a_hex(_data[:-10])) return _data[:-10] # Determine if the provided peer ID is valid for the provided network # def valid_peer(_peer_list, _peerid): # _log = logger.debug if _peerid in _peer_list: # _log('Peer List Has An Entry For: %s', binascii.b2a_hex(_peerid)) return True # _log('Peer List Does NOT Have An Entry For: %s', binascii.b2a_hex(_peerid)) return False # Determine if the provided master ID is valid for the provided network # def valid_master(_network, _peerid): # _log = logger.debug if NETWORK[_network]['MASTER']['RADIO_ID'] == _peerid: # _log('Master ID is Valid: %s', binascii.b2a_hex(_peerid)) return True else: # _log('Master ID is NOT Valid: %s', binascii.b2a_hex(_peerid)) return False # Accept a complete packet, ready to be sent, and send it to all active peers + master in an IPSC # def send_to_ipsc(_target, _packet): # _log = logger.debug # Send to the Master # _log('Sending %s to:', binascii.b2a_hex(_packet) networks[_target].transport.write(_packet, (NETWORK[_target]['MASTER']['IP'], NETWORK[_target]['MASTER']['PORT'])) # _log(' Master: %s', binascii.b2a_hex(NETWORK[_target]['MASTER']['RADIO_ID'])) # Send to each connected Peer for peer in NETWORK[_target]['PEERS']: if peer['STATUS']['CONNECTED'] == True: networks[_target].transport.write(_packet, (peer['IP'], peer['PORT'])) # _log(' Peer: %s', binascii.b2a_hex(peer['RADIO_ID'])) # De-register a peer from an IPSC by removing it's infomation # def de_register_peer(_network, _peerid): # _log = logger.debug # Iterate for the peer in our data # _log('Peer De-Registration Requested for: %s', binascii.b2a_hex(_peerid)) for peer in NETWORK[_network]['PEERS']: # If we find the peer, remove it (we should find it) if _peerid == peer['RADIO_ID']: NETWORK[_network]['PEERS'].remove(peer) # _log(' Peer Found And De-Registered') return else: # _log(' Peer NOT Found') pass # Take a recieved peer list and the network it belongs to, process and populate the # data structure in my_ipsc_config with the results, and return a simple list of peers. # def process_peer_list(_data, _network, _peer_list): # _log = logger.debug # Set the status flag to indicate we have recieved a Peer List NETWORK[_network]['MASTER']['STATUS']['PEER-LIST'] = True # Determine the length of the peer list for the parsing iterator _peer_list_length = int(binascii.b2a_hex(_data[5:7]), 16) # Record the number of peers in the data structure... we'll use it later (11 bytes per peer entry) NETWORK[_network]['LOCAL']['NUM_PEERS'] = _peer_list_length/11 # _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) # Iterate each peer entry in the peer list. Skip the header, then pull the next peer, the next, etc. for i in range(7, (_peer_list_length)+7, 11): # Extract various elements from each entry... _hex_radio_id = (_data[i:i+4]) _hex_address = (_data[i+4:i+8]) _ip_address = socket.inet_ntoa(_hex_address) _hex_port = (_data[i+8:i+10]) _port = int(binascii.b2a_hex(_hex_port), 16) _hex_mode = (_data[i+10:i+11]) _mode = int(binascii.b2a_hex(_hex_mode), 16) # mask individual Mode parameters _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 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 # If this entry was NOT already in our list, add it. # Note: We keep a "simple" peer list in addition to the large data # structure because soemtimes, we just need to identify a # peer quickly. if _hex_radio_id not in _peer_list: _peer_list.append(_hex_radio_id) NETWORK[_network]['PEERS'].append({ 'RADIO_ID': _hex_radio_id, 'IP': _ip_address, 'PORT': _port, 'MODE': _hex_mode, 'PEER_OPER': _peer_op, 'PEER_MODE': _peer_mode, 'TS1_LINK': _ts1, 'TS2_LINK': _ts2, 'STATUS': {'CONNECTED': False, 'KEEP_ALIVES_SENT': 0, 'KEEP_ALIVES_MISSED': 0, 'KEEP_ALIVES_OUTSTANDING': 0} }) return _peer_list # Gratuituous print-out of the peer list.. Pretty much debug stuff. # def print_peer_list(_network): # _log = logger.info _status = NETWORK[_network]['MASTER']['STATUS']['PEER-LIST'] print('Peer List Status for {}: {}' .format(_network, _status)) if _status and not NETWORK[_network]['PEERS']: print('We are the only peer for: %s' % _network) print('') 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' *********** #******** *********** #************************************************ #************************************************ # Base Class (used nearly all of the time) #************************************************ 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']). # Note that many of them reference each other... this is the Pythonic way. # 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. # This isn't really necessary for anything other than readability (reduction of code golf) # 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 status # Web page, etc.... # self._call = task.LoopingCall(self.timed_loop) self._loop = self._call.start(self._local['ALIVE_TIMER']) # Take a packet to be SENT, calcualte auth hash and return the whole thing # def hashed_packet(self, _key, _data): # _log = logger.debug _hash = binascii.a2b_hex((hmac.new(_key,_data,hashlib.sha1)).hexdigest()[:20]) # _log('Hash for: %s is %s', binascii.b2a_hex(_data), binascii.b2a_hex(_hash) return (_data + _hash) # Take a RECEIVED packet, calculate the auth hash and verify authenticity # def validate_auth(self, _key, _data): # _log = logger.debug _payload = strip_hash(_data) _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 #************************************************ # TIMED LOOP - MY CONNECTION MAINTENANCE #************************************************ def timed_loop(self): # Right now, without this, we really dont' know anything is happening. print_peer_list(self._network) # If the master isn't connected, we have to do that before we can do anything else! if self._master_stat['CONNECTED'] == False: reg_packet = self.hashed_packet(self._local['AUTH_KEY'], self.MASTER_REG_REQ_PKT) self.transport.write(reg_packet, (self._master_sock)) # Once the master is connected, we have to send keep-alives.. and make sure we get them back elif (self._master_stat['CONNECTED'] == True): # Send keep-alive to the master master_alive_packet = self.hashed_packet(self._local['AUTH_KEY'], self.MASTER_ALIVE_PKT) self.transport.write(master_alive_packet, (self._master_sock)) # If we had a keep-alive outstanding by the time we send another, mark it missed. if (self._master_stat['KEEP_ALIVES_OUTSTANDING']) > 0: self._master_stat['KEEP_ALIVES_MISSED'] += 1 # If we have missed too many keep-alives, de-regiseter the master and start over. 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') # Update our stats before we move on... self._master_stat['KEEP_ALIVES_SENT'] += 1 self._master_stat['KEEP_ALIVES_OUTSTANDING'] += 1 else: # This is bad. If we get this message, probably need to restart the program. logger.error('->> (%s) Master in UNKOWN STATE:%s:%s', self._network, self._master_sock) # If the master is connected and we don't have a peer-list yet.... if ((self._master_stat['CONNECTED'] == True) and (self._master_stat['PEER-LIST'] == False)): # Ask the master for a peer-list peer_list_req_packet = self.hashed_packet(self._local['AUTH_KEY'], self.PEER_LIST_REQ_PKT) self.transport.write(peer_list_req_packet, (self._master_sock)) # If we do ahve a peer-list, we need to register with the peers and send keep-alives... if (self._master_stat['PEER-LIST'] == True): # Iterate the list of peers... so we do this for each one. for peer in (self._peers): # We will show up in the peer list, but shouldn't try to talk to ourselves. if (peer['RADIO_ID'] == self._local_id): continue # If we haven't registered to a peer, send a registration if peer['STATUS']['CONNECTED'] == False: peer_reg_packet = self.hashed_packet(self._local['AUTH_KEY'], self.PEER_REG_REQ_PKT) self.transport.write(peer_reg_packet, (peer['IP'], peer['PORT'])) # If we have registered with the peer, then send a keep-alive elif peer['STATUS']['CONNECTED'] == True: peer_alive_req_packet = self.hashed_packet(self._local['AUTH_KEY'], self.PEER_ALIVE_REQ_PKT) self.transport.write(peer_alive_req_packet, (peer['IP'], peer['PORT'])) # If we have a keep-alive outstanding by the time we send another, mark it missed. if peer['STATUS']['KEEP_ALIVES_OUTSTANDING'] > 0: peer['STATUS']['KEEP_ALIVES_MISSED'] += 1 # If we have missed too many keep-alives, de-register the peer and start over. 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) # Update our stats before moving on... peer['STATUS']['KEEP_ALIVES_SENT'] += 1 peer['STATUS']['KEEP_ALIVES_OUTSTANDING'] += 1 def _notify_event(self, network, event, info): """ Used internally whenever an event happens that may be useful to notify the outside world about. Arguments: network: string, network name to look up in config event: string, basic description info: dict, in the interest of accomplishing as much as possible without code changes. The dict will typically contain a peer_id so the origin of the event is known. """ pass #************************************************ # RECEIVED DATAGRAM - ACT IMMEDIATELY!!! #************************************************ # Actions for recieved packets by type: For every packet recieved, there are some things that we need to do: # Decode some of the info # Check for auth and authenticate the packet # Strip the hash from the end... we don't need it anymore # # Once they're done, we move on to the proccessing or callbacks for each packet type. # 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: # Validate if self.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 # Strip the hash, we won't need it anymore data = strip_hash(data) # Packets generated by "users" that are the most common should come first for efficiency. # if (_packettype == GROUP_VOICE): # Don't take action unless it's from a valid peer (including the master, of course) 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 self._notify_event(self._network, 'group_voice', {'peer_id': _dec_peerid}) group_voice(self._network, data) # IPSC keep alives, master and peer, come next in processing priority # elif (_packettype == PEER_ALIVE_REQ): # We should not answer a keep-alive request from a peer we don't know about! 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 # Generate a hashed paket from our template and send it. peer_alive_reply_packet = self.hashed_packet(self._local['AUTH_KEY'], self.PEER_ALIVE_REPLY_PKT) self._notify_event(self._network, 'peer_keepalive', {'peer_id': _dec_peerid}) self.transport.write(peer_alive_reply_packet, (host, port)) elif (_packettype == MASTER_ALIVE_REPLY): # We should not accept keep-alive reply from someone claming to be a master who isn't! 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) # This action is so simple, it doesn't require a callback function, master is responding, we're good. self._master_stat['KEEP_ALIVES_OUTSTANDING'] = 0 elif (_packettype == PEER_ALIVE_REPLY): # Find the peer in our list of peers... for peer in self._config['PEERS']: if peer['RADIO_ID'] == _peerid: # No callback funcntion needed, set the outstanding keepalives to 0, and move on. 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): # We can't operate as a master as of now, so we should never receive one of these. # logger.debug('<<- (%s) Master Registration Packet Recieved', self._network) pass # When we hear from the maseter, record it's ID, flag that we're connected, and reset the dead counter. elif (_packettype == MASTER_REG_REPLY): self._master['RADIO_ID'] = _peerid self._master_stat['CONNECTED'] = True self._master_stat['KEEP_ALIVES_OUTSTANDING'] = 0 # Answer a peer registration request -- simple, no callback runction needed elif (_packettype == PEER_REG_REQ): if valid_peer(self._peer_list, _peerid): peer_reg_reply_packet = self.hashed_packet(self._local['AUTH_KEY'], self.PEER_REG_REPLY_PKT) self.transport.write(peer_reg_reply_packet, (host, port)) self._notify_event(self._network, 'peer_registration', {'peer_id': _dec_peerid}) elif (_packettype == PEER_REG_REPLY): self._notify_event(self._network, 'peer_registration_reply', {'peer_id': _dec_peerid}) for peer in self._config['PEERS']: if peer['RADIO_ID'] == _peerid: peer['STATUS']['CONNECTED'] = True elif (_packettype == PEER_LIST_REPLY): if len(data) > 18: self._peer_list = process_peer_list(data, self._network, self._peer_list) else: NETWORK[self._network]['MASTER']['STATUS']['PEER-LIST'] = True elif (_packettype == DE_REG_REQ): de_register_peer(self._network, _peerid) 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) # Other "user" related packet types that we don't do much or anything with yet # elif (_packettype == PVT_VOICE): private_voice() elif (_packettype == GROUP_DATA): group_data() elif (_packettype == PVT_DATA): private_data() elif (_packettype == XCMP_XNL): # NOTE: We currently indicate we are not XCMP/XNL capable! xcmp_xnl() elif (_packettype == CALL_CTL_1): call_control_1() elif (_packettype == CALL_CTL_2): call_control_2() elif (_packettype == CALL_CTL_3): call_control_3() # 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: unknown_message(_packettype, data) #************************************************ # Derived Class # used in the rare event of an # unauthenticated IPSC network. #************************************************ class UnauthIPSC(IPSC): # There isn't a hash to build, so just return the data # def hashed_packet(self, _key, _data): return (_data) # Everything is validated, so just return True # def validate_auth(self, _key, _data): return True #************************************************ # MAIN PROGRAM LOOP STARTS HERE #************************************************ if __name__ == '__main__': networks = {} for ipsc_network in NETWORK: if (NETWORK[ipsc_network]['LOCAL']['ENABLED']): if NETWORK[ipsc_network]['LOCAL']['AUTH_ENABLED'] == True: networks[ipsc_network] = IPSC(ipsc_network) else: networks[ipsc_network] = UnauthIPSC(ipsc_network) reactor.listenUDP(NETWORK[ipsc_network]['LOCAL']['PORT'], networks[ipsc_network]) reactor.run()