DMRlink/ipsc.py

# 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 ConfigParser
import os
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 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')
   

#************************************************
#     PARSE THE CONFIG FILE AND BUILD STRUCTURE
#************************************************

ACTIVE_CALLS = []

NETWORK = {}

config = ConfigParser.ConfigParser()
config.read('./dmrlink.cfg')

for section in config.sections():
    NETWORK.update({section: {'LOCAL': {}, 'MASTER': {}, 'PEERS': []}})
    NETWORK[section]['LOCAL'].update({
        'MODE': '',
        'PEER_OPER': True,
        'PEER_MODE': 'DIGITAL',
        'FLAGS': '',
        'MAX_MISSED': 5,
        'NUM_PEERS': 0,
        'STATUS': {
            'ACTIVE': False
            },
        'ENABLED': config.getboolean(section, 'ENABLED'),
        'TS1_LINK': config.getboolean(section, 'TS1_LINK'),
        'TS2_LINK': config.getboolean(section, 'TS2_LINK'),
        'AUTH_ENABLED': config.getboolean(section, 'AUTH_ENABLED'),
        'RADIO_ID': (config.get(section, 'RADIO_ID').rjust(8,'0')).decode('hex'),
        'PORT': config.getint(section, 'PORT'),
        'ALIVE_TIMER': config.getint(section, 'ALIVE_TIMER'),
        'AUTH_KEY': (config.get(section, 'AUTH_KEY').rjust(40,'0')).decode('hex'),
        })
    NETWORK[section]['MASTER'].update({
        'RADIO_ID': '\x00\x00\x00\x00',
        'MODE': '\x00',
        'PEER_OPER': False,
        'PEER_MODE': '',
        'TS1_LINK': False,
        'TS2_LINK': False,
        'FLAGS': '\x00\x00\x00\x00',
        'STATUS': {
            'CONNECTED': False,
            'PEER-LIST': False,
            'KEEP_ALIVES_SENT': 0,
            'KEEP_ALIVES_MISSED': 0,
            'KEEP_ALIVES_OUTSTANDING': 0 
        },
        'IP': config.get(section, 'MASTER_IP'),
        'PORT': config.getint(section, 'MASTER_PORT')
        })
        
    if NETWORK[section]['LOCAL']['AUTH_ENABLED']:
        NETWORK[section]['LOCAL']['FLAGS'] = '\x00\x00\x00\x14'
    else:
        NETWORK[section]['LOCAL']['FLAGS'] = '\x00\x00\x00\x04'
    
    if not NETWORK[section]['LOCAL']['TS1_LINK'] and not NETWORK[section]['LOCAL']['TS2_LINK']:    
        NETWORK[section]['LOCAL']['MODE'] = '\x65'
    elif NETWORK[section]['LOCAL']['TS1_LINK'] and not NETWORK[section]['LOCAL']['TS2_LINK']:    
        NETWORK[section]['LOCAL']['MODE'] = '\x66'
    elif not NETWORK[section]['LOCAL']['TS1_LINK'] and NETWORK[section]['LOCAL']['TS2_LINK']:    
        NETWORK[section]['LOCAL']['MODE'] = '\x69'
    else:
        NETWORK[section]['LOCAL']['MODE'] = '\x6A'

#************************************************
#     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(_network, _data):
#    _log = logger.debug
    _src_sub = int(binascii.b2a_hex(_data[6:9]), 16)
    _src_group = int(binascii.b2a_hex(_data[9:12]), 16)
    _src_ipsc = int(binascii.b2a_hex(_data[1:5]), 16)
    _call  = binascii.b2a_hex(_data[17:18])
    
    if _call == '00':
        if (_network, 'Slot 1') not in ACTIVE_CALLS:
            ACTIVE_CALLS.append((_network, 'Slot 1'))
            print('({}) CALL START Group Voice: IPSC SRC {}, RF SRC: {}, DST Group {}, Slot 1' .format(_network, _src_ipsc, _src_sub, _src_group))
    
    if _call == '20':
        if (_network, 'Slot 2') not in ACTIVE_CALLS:
            ACTIVE_CALLS.append((_network, 'Slot 2'))
            print('({}) CALL START Group Voice: IPSC SRC {}, RF SRC: {}, DST Group {}, Slot 2' .format(_network, _src_ipsc, _src_sub, _src_group))
    
    if _call == '40':
        ACTIVE_CALLS.remove((_network, 'Slot 1'))
        print('({}) CALL END Group Voice:   IPSC SRC {}, RF SRC: {}, DST Group {}, Slot 1' .format(_network, _src_ipsc, _src_sub, _src_group))
        
    if _call == '60':
        ACTIVE_CALLS.remove((_network, 'Slot 2'))
        print('({}) CALL END Group Voice:   IPSC SRC {}, RF SRC: {}, DST Group {}, Slot 2' .format(_network, _src_ipsc, _src_sub, _src_group))
    
    '''
    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()