DMRlink/dmrlink.py

#!/usr/bin/env python
#
# 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.

#NOTE: This program uses a configuration file specified on the command line
#      if none is specified, then dmrlink.cfg in the same directory as this
#      file will be tried. Finally, if that does not exist, this process
#      will terminate

from __future__ import print_function

import ConfigParser
import argparse
import sys
import binascii
import csv
import os
import logging
import signal

from logging.config import dictConfig
from hmac import new as hmac_new
from binascii import b2a_hex as h
from hashlib import sha1
from socket import inet_ntoa as IPAddr
from socket import inet_aton as IPHexStr
from socket import gethostbyname 
from twisted.internet.protocol import DatagramProtocol
from twisted.internet import reactor
from twisted.internet import task
from random import randint
from time import time
from cPickle import dump as pickle_dump

__author__ = 'Cortney T. Buffington, N0MJS'
__copyright__ = 'Copyright (c) 2013 - 2016 Cortney T. Buffington, N0MJS and the K0USY Group'
__credits__ = 'Adam Fast, KC0YLK; Dave Kierzkowski, KD8EYF; Steve Zingman, N4IRS; Mike Zingman, N4IRR'
__license__ = 'Creative Commons Attribution-ShareAlike 3.0 Unported'
__maintainer__ = 'Cort Buffington, N0MJS'
__email__ = 'n0mjs@me.com'
__status__ = 'beta'

# Change the current directory to the location of the application
os.chdir(os.path.dirname(os.path.realpath(sys.argv[0])))

parser = argparse.ArgumentParser()
parser.add_argument('-c', '--config', action='store', dest='CFG_FILE', help='/full/path/to/config.file (usually dmrlink.cfg)')

cli_args = parser.parse_args()

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

NETWORK = {}
networks = {}
config = ConfigParser.ConfigParser()

if not cli_args.CFG_FILE:
    cli_args.CFG_FILE = os.path.dirname(os.path.abspath(__file__))+'/dmrlink.cfg'
try:
    if not config.read(cli_args.CFG_FILE):
        sys.exit('Configuration file \''+cli_args.CFG_FILE+'\' is not a valid configuration file! Exiting...')        
except:    
    sys.exit('Configuration file \''+cli_args.CFG_FILE+'\' is not a valid configuration file! Exiting...')

try:
    for section in config.sections():
        if section == 'GLOBAL':
            # Process GLOBAL items in the configuration
            PATH = config.get(section, 'PATH')

        elif section == 'REPORTS':
            # Process REPORTS items in the configuration
            REPORTS = {
                'REPORT_NETWORKS': config.get(section, 'REPORT_NETWORKS'),
                'REPORT_INTERVAL': config.getint(section, 'REPORT_INTERVAL'),
                'REPORT_PATH': config.get(section, 'REPORT_PATH'),
                'PRINT_PEERS_INC_MODE': config.getboolean(section, 'PRINT_PEERS_INC_MODE'),
                'PRINT_PEERS_INC_FLAGS': config.getboolean(section, 'PRINT_PEERS_INC_FLAGS')
            }

        elif section == 'LOGGER':
            # Process LOGGER items in the configuration
            LOGGER = {
                'LOG_FILE': config.get(section, 'LOG_FILE'),
                'LOG_HANDLERS': config.get(section, 'LOG_HANDLERS'),
                'LOG_LEVEL': config.get(section, 'LOG_LEVEL'),
                'LOG_NAME': config.get(section, 'LOG_NAME')
            }
        elif config.getboolean(section, 'ENABLED'):
            # All other sections define indiviual IPSC Networks we connect to
            # Each IPSC network config will contain the following three sections
            NETWORK.update({section: {'LOCAL': {}, 'MASTER': {}, 'PEERS': {}}})
            # LOCAL means we need to know this stuff to be a peer in the network
            NETWORK[section]['LOCAL'].update({
                # In case we want to keep config, but not actually connect to the network
                'ENABLED':      config.getboolean(section, 'ENABLED'),
                
                # These items are used to create the MODE byte
                'PEER_OPER':    config.getboolean(section, 'PEER_OPER'),
                'IPSC_MODE':    config.get(section, 'IPSC_MODE'),
                'TS1_LINK':     config.getboolean(section, 'TS1_LINK'),
                'TS2_LINK':     config.getboolean(section, 'TS2_LINK'),
                'MODE': '',
                
                # These items are used to create the multi-byte FLAGS field
                'AUTH_ENABLED': config.getboolean(section, 'AUTH_ENABLED'),
                'CSBK_CALL':    config.getboolean(section, 'CSBK_CALL'),
                'RCM':          config.getboolean(section, 'RCM'),
                'CON_APP':      config.getboolean(section, 'CON_APP'),
                'XNL_CALL':     config.getboolean(section, 'XNL_CALL'),
                'XNL_MASTER':   config.getboolean(section, 'XNL_MASTER'),
                'DATA_CALL':    config.getboolean(section, 'DATA_CALL'),
                'VOICE_CALL':   config.getboolean(section, 'VOICE_CALL'),
                'MASTER_PEER':  config.getboolean(section, 'MASTER_PEER'),
                'FLAGS': '',
                
                # Things we need to know to connect and be a peer in this IPSC
                'RADIO_ID':     hex(int(config.get(section, 'RADIO_ID')))[2:].rjust(8,'0').decode('hex'),
                'IP':           gethostbyname(config.get(section, 'IP')),
                'PORT':         config.getint(section, 'PORT'),
                'ALIVE_TIMER':  config.getint(section, 'ALIVE_TIMER'),
                'MAX_MISSED':   config.getint(section, 'MAX_MISSED'),
                'AUTH_KEY':     (config.get(section, 'AUTH_KEY').rjust(40,'0')).decode('hex'),
                'NUM_PEERS': 0,
                })
            # Master means things we need to know about the master peer of the network
            NETWORK[section]['MASTER'].update({
                'RADIO_ID': '\x00\x00\x00\x00',
                'MODE': '\x00',
                'MODE_DECODE': '',
                'FLAGS': '\x00\x00\x00\x00',
                'FLAGS_DECODE': '',
                'STATUS': {
                    'CONNECTED':               False,
                    'PEER_LIST':               False,
                    'KEEP_ALIVES_SENT':        0,
                    'KEEP_ALIVES_MISSED':      0,
                    'KEEP_ALIVES_OUTSTANDING': 0,
                    'KEEP_ALIVES_RECEIVED':    0,
                    'KEEP_ALIVE_RX_TIME':      0
                    },
                'IP': '',
                'PORT': ''
                })
            if not NETWORK[section]['LOCAL']['MASTER_PEER']:
                NETWORK[section]['MASTER'].update({
                    'IP': gethostbyname(config.get(section, 'MASTER_IP')),
                    'PORT': config.getint(section, 'MASTER_PORT')
                })
            
            # Temporary locations for building MODE and FLAG data
            MODE_BYTE = 0
            FLAG_1 = 0
            FLAG_2 = 0
            
            # Construct and store the MODE field
            if NETWORK[section]['LOCAL']['PEER_OPER']:
                MODE_BYTE |= 1 << 6
            if NETWORK[section]['LOCAL']['IPSC_MODE'] == 'ANALOG':
                MODE_BYTE |= 1 << 4
            elif NETWORK[section]['LOCAL']['IPSC_MODE'] == 'DIGITAL':
                MODE_BYTE |= 1 << 5
            if NETWORK[section]['LOCAL']['TS1_LINK']:
                MODE_BYTE |= 1 << 3
            else:
                MODE_BYTE |= 1 << 2
            if NETWORK[section]['LOCAL']['TS2_LINK']:
                MODE_BYTE |= 1 << 1
            else:
                MODE_BYTE |= 1 << 0
            NETWORK[section]['LOCAL']['MODE'] = chr(MODE_BYTE)

            # Construct and store the FLAGS field
            if NETWORK[section]['LOCAL']['CSBK_CALL']:
                FLAG_1 |= 1 << 7  
            if NETWORK[section]['LOCAL']['RCM']:
                FLAG_1 |= 1 << 6
            if NETWORK[section]['LOCAL']['CON_APP']:
                FLAG_1 |= 1 << 5
            if NETWORK[section]['LOCAL']['XNL_CALL']:
                FLAG_2 |= 1 << 7    
            if NETWORK[section]['LOCAL']['XNL_CALL'] and NETWORK[section]['LOCAL']['XNL_MASTER']:
                FLAG_2 |= 1 << 6
            elif NETWORK[section]['LOCAL']['XNL_CALL'] and not NETWORK[section]['LOCAL']['XNL_MASTER']:
                FLAG_2 |= 1 << 5
            if NETWORK[section]['LOCAL']['AUTH_ENABLED']:
                FLAG_2 |= 1 << 4
            if NETWORK[section]['LOCAL']['DATA_CALL']:
                FLAG_2 |= 1 << 3
            if NETWORK[section]['LOCAL']['VOICE_CALL']:
                FLAG_2 |= 1 << 2
            if NETWORK[section]['LOCAL']['MASTER_PEER']:
                FLAG_2 |= 1 << 0
            NETWORK[section]['LOCAL']['FLAGS'] = '\x00\x00'+chr(FLAG_1)+chr(FLAG_2)
except:
    sys.exit('Could not parse configuration file, exiting...')


#************************************************
#     CONFIGURE THE SYSTEM LOGGER
#************************************************

dictConfig({
    'version': 1,
    'disable_existing_loggers': False,
    'filters': {
    },
    'formatters': {
        'verbose': {
            'format': '%(levelname)s %(asctime)s %(module)s %(process)d %(thread)d %(message)s'
        },
        'timed': {
            'format': '%(levelname)s %(asctime)s %(message)s'
        },
        'simple': {
            'format': '%(levelname)s %(message)s'
        },
        'syslog': {
            'format': '%(name)s (%(process)d): %(levelname)s %(message)s'
        }
    },
    'handlers': {
        'null': {
            'class': 'logging.NullHandler'
        },
        'console': {
            'class': 'logging.StreamHandler',
            'formatter': 'simple'
        },
        'console-timed': {
            'class': 'logging.StreamHandler',
            'formatter': 'timed'
        },
        'file': {
            'class': 'logging.FileHandler',
            'formatter': 'simple',
            'filename': LOGGER['LOG_FILE'],
        },
        'file-timed': {
            'class': 'logging.FileHandler',
            'formatter': 'timed',
            'filename': LOGGER['LOG_FILE'],
        },
        'syslog': {
            'class': 'logging.handlers.SysLogHandler',
            'formatter': 'syslog',
        }
    },
    'loggers': {
        LOGGER['LOG_NAME']: {
            'handlers': LOGGER['LOG_HANDLERS'].split(','),
            'level': LOGGER['LOG_LEVEL'],
            'propagate': True,
        }
    }
})
logger = logging.getLogger(LOGGER['LOG_NAME'])


#************************************************
#     IMPORTING OTHER FILES - '#include'
#************************************************

# 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')

# Import the Alias files for numeric ids. This is split to save
# time making lookups in one huge dictionary
#
curdir= os.path.dirname(__file__)
subscriber_ids = {}
peer_ids = {}
talkgroup_ids = {}

try:
    with open(PATH+'subscriber_ids.csv', 'rU') as subscriber_ids_csv:
        subscribers = csv.reader(subscriber_ids_csv, dialect='excel', delimiter=',')
        for row in subscribers:
            subscriber_ids[int(row[0])] = (row[1])
except ImportError:
    logger.warning('subscriber_ids.csv not found: Subscriber aliases will not be available')

try:
    with open(PATH+'peer_ids.csv', 'rU') as peer_ids_csv:
        peers = csv.reader(peer_ids_csv, dialect='excel', delimiter=',')
        for row in peers:
            peer_ids[int(row[0])] = (row[1])
except ImportError:
    logger.warning('peer_ids.csv not found: Peer aliases will not be available')

try:
    with open(PATH+'talkgroup_ids.csv', 'rU') as talkgroup_ids_csv:
        talkgroups = csv.reader(talkgroup_ids_csv, dialect='excel', delimiter=',')
        for row in talkgroups:
            talkgroup_ids[int(row[1])] = (row[0])
except ImportError:
    logger.warning('talkgroup_ids.csv not found: Talkgroup aliases will not be available')


#************************************************
#     UTILITY FUNCTIONS FOR INTERNAL USE
#************************************************

# Create a 2 byte hex string from an integer
#
def hex_str_2(_int_id):
    try:
        return hex(_int_id)[2:].rjust(4,'0').decode('hex')
    except TypeError:
        logger.error('hex_str_2: invalid integer length')
     
# Create a 3 byte hex string from an integer
#
def hex_str_3(_int_id):
    try:
        return hex(_int_id)[2:].rjust(6,'0').decode('hex')
    except TypeError:
        logger.error('hex_str_3: invalid integer length')

# Create a 4 byte hex string from an integer
#
def hex_str_4(_int_id):
    try:
        return hex(_int_id)[2:].rjust(8,'0').decode('hex')
    except TypeError:
        logger.error('hex_str_4: invalid integer length')

# Convert a hex string to an int (radio ID, etc.)
#
def int_id(_hex_string):
    return int(h(_hex_string), 16)

# Re-Write Source Radio-ID (DMR NAT)
#
def dmr_nat(_data, _src_id, _nat_id):
    _data = _data.replace(_src_id, _nat_id)
    return _data

# Lookup text data for numeric IDs
#
def get_info(_id, _dict):
    if _id in _dict:
        return _dict[_id]
    return _id

# 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


# De-register a peer from an IPSC by removing it's information
#
def de_register_peer(_network, _peerid):
    # Iterate for the peer in our data
    if _peerid in NETWORK[_network]['PEERS'].keys():
        del NETWORK[_network]['PEERS'][_peerid]
        logger.info('(%s) Peer De-Registration Requested for: %s', _network, int_id(_peerid))
        return
    else:
        logger.warning('(%s) Peer De-Registration Requested for: %s, but we don\'t have a listing for this peer', _network, int_id(_peerid))
        pass


# Process the MODE byte in registration/peer list packets for determining master and peer capabilities
#
def process_mode_byte(_hex_mode):
    _mode = int(h(_hex_mode), 16)
    
    # Determine whether or not the peer is operational
    _peer_op = bool(_mode & PEER_OP_MSK)    
    # Determine whether or not timeslot 1 is linked
    _ts1 = bool(_mode & IPSC_TS1_MSK)  
    # Determine whether or not timeslot 2 is linked
    _ts2 = bool(_mode & IPSC_TS2_MSK)
     
    # Determine the operational mode of the peer
    if _mode & PEER_MODE_MSK == PEER_MODE_MSK:
        _peer_mode = 'UNKNOWN'
    elif not _mode & PEER_MODE_MSK:
        _peer_mode = 'NO_RADIO'
    elif _mode & PEER_MODE_ANALOG:
        _peer_mode = 'ANALOG'
    elif _mode & PEER_MODE_DIGITAL:
        _peer_mode = 'DIGITAL'
    
    return {
        'PEER_OP': _peer_op,
        'PEER_MODE': _peer_mode,
        'TS_1': _ts1,
        'TS_2': _ts2
        }


# Process the FLAGS bytes in registration replies for determining what services are available
#
def process_flags_bytes(_hex_flags):
    _byte3 = int(h(_hex_flags[2]), 16)
    _byte4 = int(h(_hex_flags[3]), 16)
    
    _csbk       = bool(_byte3 & CSBK_MSK)
    _rpt_mon    = bool(_byte3 & RPT_MON_MSK)
    _con_app    = bool(_byte3 & CON_APP_MSK)
    _xnl_con    = bool(_byte4 & XNL_STAT_MSK)
    _xnl_master = bool(_byte4 & XNL_MSTR_MSK)
    _xnl_slave  = bool(_byte4 & XNL_SLAVE_MSK)
    _auth       = bool(_byte4 & PKT_AUTH_MSK)
    _data       = bool(_byte4 & DATA_CALL_MSK)
    _voice      = bool(_byte4 & VOICE_CALL_MSK)
    _master     = bool(_byte4 & MSTR_PEER_MSK)
    
    return {
        'CSBK': _csbk,
        'RCM': _rpt_mon,
        'CON_APP': _con_app,
        'XNL_CON': _xnl_con,
        'XNL_MASTER': _xnl_master,
        'XNL_SLAVE': _xnl_slave,
        'AUTH': _auth,
        'DATA': _data,
        'VOICE': _voice,
        'MASTER': _master
        } 
        
        
# Take a received 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):
    # Create a temporary peer list to track who we should have in our list -- used to find old peers we should remove.
    _temp_peers = []
    # Determine the length of the peer list for the parsing iterator
    _peer_list_length = int(h(_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
    logger.info('(%s) Peer List Received from Master: %s peers in this IPSC', _network, NETWORK[_network]['LOCAL']['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   = IPAddr(_hex_address)
        _hex_port     = (_data[i+8:i+10])
        _port         = int(h(_hex_port), 16)
        _hex_mode     = (_data[i+10:i+11])
     
        # Add this peer to a temporary PeerID list - used to remove any old peers no longer with us
        _temp_peers.append(_hex_radio_id)
        
        # This is done elsewhere for the master too, so we use a separate function
        _decoded_mode = process_mode_byte(_hex_mode)

        # If this entry WAS already in our list, update everything except the stats
        # in case this was a re-registration with a different mode, flags, etc.
        if _hex_radio_id in NETWORK[_network]['PEERS'].keys():
            NETWORK[_network]['PEERS'][_hex_radio_id]['IP'] = _ip_address
            NETWORK[_network]['PEERS'][_hex_radio_id]['PORT'] = _port
            NETWORK[_network]['PEERS'][_hex_radio_id]['MODE'] = _hex_mode
            NETWORK[_network]['PEERS'][_hex_radio_id]['MODE_DECODE'] = _decoded_mode
            NETWORK[_network]['PEERS'][_hex_radio_id]['FLAGS'] = ''
            NETWORK[_network]['PEERS'][_hex_radio_id]['FLAGS_DECODE'] = ''
            logger.debug('(%s) Peer Updated: %s', _network, NETWORK[_network]['PEERS'][_hex_radio_id])

        # If this entry was NOT already in our list, add it.
        if _hex_radio_id not in NETWORK[_network]['PEERS'].keys():
            NETWORK[_network]['PEERS'][_hex_radio_id] = {
                'IP':          _ip_address, 
                'PORT':        _port, 
                'MODE':        _hex_mode,            
                'MODE_DECODE': _decoded_mode,
                'FLAGS': '',
                'FLAGS_DECODE': '',
                'STATUS': {
                    'CONNECTED':               False,
                    'KEEP_ALIVES_SENT':        0,
                    'KEEP_ALIVES_MISSED':      0,
                    'KEEP_ALIVES_OUTSTANDING': 0,
                    'KEEP_ALIVES_RECEIVED':    0,
                    'KEEP_ALIVE_RX_TIME':      0
                    }
                }
            logger.debug('(%s) Peer Added: %s', _network, NETWORK[_network]['PEERS'][_hex_radio_id])
    
    # Finally, check to see if there's a peer already in our list that was not in this peer list
    # and if so, delete it.
    for peer in NETWORK[_network]['PEERS'].keys():
        if peer not in _temp_peers:
            de_register_peer(_network, peer)
            logger.warning('(%s) Peer Deleted (not in new peer list): %s', _network, int_id(peer))

# Build a peer list - used when a peer registers, re-regiseters or times out
#
def build_peer_list(_peers):
    concatenated_peers = ''
    for peer in _peers:
        hex_ip = IPHexStr(_peers[peer]['IP'])
        hex_port = hex_str_2(_peers[peer]['PORT'])
        mode = _peers[peer]['MODE']        
        concatenated_peers += peer + hex_ip + hex_port + mode
    
    peer_list = hex_str_2(len(concatenated_peers)) + concatenated_peers
    return peer_list

# Gratuitous print-out of the peer list.. Pretty much debug stuff.
#
def print_peer_list(_network):
    _peers = NETWORK[_network]['PEERS']
    
    _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 peer in _peers.keys():
        _this_peer = _peers[peer]
        _this_peer_stat = _this_peer['STATUS']
        
        if peer == NETWORK[_network]['LOCAL']['RADIO_ID']:
            me = '(self)'
        else:
            me = ''
             
        print('\tRADIO ID: {} {}' .format(int_id(peer), me))
        print('\t\tIP Address: {}:{}' .format(_this_peer['IP'], _this_peer['PORT']))
        if _this_peer['MODE_DECODE'] and REPORTS['PRINT_PEERS_INC_MODE']:
            print('\t\tMode Values:')
            for name, value in _this_peer['MODE_DECODE'].items():
                print('\t\t\t{}: {}' .format(name, value))
        if _this_peer['FLAGS_DECODE'] and REPORTS['PRINT_PEERS_INC_FLAGS']:
            print('\t\tService Flags:')
            for name, value in _this_peer['FLAGS_DECODE'].items():
                print('\t\t\t{}: {}' .format(name, value))
        print('\t\tStatus: {},  KeepAlives Sent: {},  KeepAlives Outstanding: {},  KeepAlives Missed: {}' .format(_this_peer_stat['CONNECTED'], _this_peer_stat['KEEP_ALIVES_SENT'], _this_peer_stat['KEEP_ALIVES_OUTSTANDING'], _this_peer_stat['KEEP_ALIVES_MISSED']))
        print('\t\t                KeepAlives Received: {},  Last KeepAlive Received at: {}' .format(_this_peer_stat['KEEP_ALIVES_RECEIVED'], _this_peer_stat['KEEP_ALIVE_RX_TIME']))
        
    print('')
 
# Gratuitous print-out of Master info.. Pretty much debug stuff.
#
def print_master(_network):
    if NETWORK[_network]['LOCAL']['MASTER_PEER']:
        print('DMRlink is the Master for %s' % _network)
    else:
        _master = NETWORK[_network]['MASTER']
        print('Master for %s' % _network)
        print('\tRADIO ID: {}' .format(int(h(_master['RADIO_ID']), 16)))
        if _master['MODE_DECODE'] and REPORTS['PRINT_PEERS_INC_MODE']:
            print('\t\tMode Values:')
            for name, value in _master['MODE_DECODE'].items():
                print('\t\t\t{}: {}' .format(name, value))
        if _master['FLAGS_DECODE'] and REPORTS['PRINT_PEERS_INC_FLAGS']:
            print('\t\tService Flags:')
            for name, value in _master['FLAGS_DECODE'].items():
                print('\t\t\t{}: {}' .format(name, value))
        print('\t\tStatus: {},  KeepAlives Sent: {},  KeepAlives Outstanding: {},  KeepAlives Missed: {}' .format(_master['STATUS']['CONNECTED'], _master['STATUS']['KEEP_ALIVES_SENT'], _master['STATUS']['KEEP_ALIVES_OUTSTANDING'], _master['STATUS']['KEEP_ALIVES_MISSED']))
        print('\t\t                KeepAlives Received: {},  Last KeepAlive Received at: {}' .format(_master['STATUS']['KEEP_ALIVES_RECEIVED'], _master['STATUS']['KEEP_ALIVE_RX_TIME']))
    
    
# Timed loop used for reporting IPSC status
#
# REPORT BASED ON THE TYPE SELECTED IN THE MAIN CONFIG FILE
if REPORTS['REPORT_NETWORKS'] == 'PICKLE':
    def reporting_loop():  
        logger.debug('Periodic Reporting Loop Started (PICKLE)')
        try:
            with open(REPORTS['REPORT_PATH']+'dmrlink_stats.pickle', 'wb') as file:
                pickle_dump(NETWORK, file, 2)
                file.close()
        except IOError as detail:
            logger.error('I/O Error: %s', detail)
        
elif REPORTS['REPORT_NETWORKS'] == 'PRINT':
    def reporting_loop():      
        logger.debug('Periodic Reporting Loop Started (PRINT)')
        print_master(NETWORK)
        print_peer_list(NETWORK)

else:
    def reporting_loop():
        logger.debug('Periodic Reporting Loop Started (NULL)')


# Shut ourselves down gracefully with the IPSC peers.
#
def handler(_signal, _frame):
    logger.info('*** DMRLINK IS TERMINATING WITH SIGNAL %s ***', str(_signal))
    
    for network in networks:
        this_ipsc = networks[network]
        logger.info('De-Registering from IPSC %s', network)
        de_reg_req_pkt = this_ipsc.hashed_packet(this_ipsc._local['AUTH_KEY'], this_ipsc.DE_REG_REQ_PKT)
        this_ipsc.send_to_ipsc(de_reg_req_pkt)
    
    reactor.stop()

# Set signal handers so that we can gracefully exit if need be
for sig in [signal.SIGTERM, signal.SIGINT, signal.SIGQUIT]:
    signal.signal(sig, handler)

#************************************************
#********                             ***********
#********    IPSC Network 'Engine'    ***********
#********                             ***********
#************************************************

#************************************************
#     Base Class (used nearly all of the time)
#************************************************


class IPSC(DatagramProtocol):
    
    #************************************************
    #     IPSC INSTANCE INSTANTIATION
    #************************************************
    
    # Modify the initializer to set up our environment and build the packets
    # we need to maintain 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_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)
            #
            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)
            #
            # General Items
            self.TS_FLAGS               = (self._local['MODE'] + self._local['FLAGS'])
            #
            # Peer Link Maintenance Packets 
            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)
            #
            # Master Link Maintenance Packets
            # self.MASTER_REG_REPLY_PKT   is not static and must be generated when it is sent
            self.MASTER_ALIVE_REPLY_PKT = (MASTER_ALIVE_REPLY + self._local_id + self.TS_FLAGS + IPSC_VER)
            self.PEER_LIST_REPLY_PKT    = (PEER_LIST_REPLY + self._local_id)
            #
            # General Link Maintenance Packets
            self.DE_REG_REQ_PKT         = (DE_REG_REQ + self._local_id)
            self.DE_REG_REPLY_PKT       = (DE_REG_REPLY + self._local_id)
            #
            logger.info('(%s) IPSC Instance Created: %s, %s:%s', self._network, int_id(self._local['RADIO_ID']), self._local['IP'], self._local['PORT'])
        else:
            # If we didn't get called correctly, log it!
            #
            logger.error('(%s) IPSC Instance Could Not be Created... Exiting', self._network)
            sys.exit()
        
        # Choose which set of fucntions to use - authenticated or not
        if self._local['AUTH_ENABLED']:
            self.hashed_packet = self.auth_hashed_packet
            self.strip_hash = self.auth_strip_hash
            self.validate_auth = self.auth_validate_auth
        else:
            self.hashed_packet = self.unauth_hashed_packet
            self.strip_hash = self.unauth_strip_hash
            self.validate_auth = self.unauth_validate_auth


    #************************************************
    #     CALLBACK FUNCTIONS FOR USER PACKET TYPES
    #************************************************

    def call_mon_status(self, _network, _data):
        logger.debug('(%s) Repeater Call Monitor Origin Packet Received: %s',_network, h(_data))
    
    def call_mon_rpt(self, _network, _data):
        logger.debug('(%s) Repeater Call Monitor Repeating Packet Received: %s', _network, h(_data))
    
    def call_mon_nack(self, _network, _data):
        logger.debug('(%s) Repeater Call Monitor NACK Packet Received: %s', _network, h(_data))
    
    def xcmp_xnl(self, _network, _data):
        logger.debug('(%s) XCMP/XNL Packet Received: %s', _network, h(_data))
        
    def repeater_wake_up(self, _network, _data):
        logger.debug('(%s) Repeater Wake-Up Packet Received: %s', _network, h(_data))
        
    def group_voice(self, _network, _src_sub, _dst_sub, _ts, _end, _peerid, _data):
        logger.debug('(%s) Group Voice Packet Received From: %s, IPSC Peer %s, Destination %s', _network, int_id(_src_sub), int_id(_peerid), int_id(_dst_sub))
    
    def private_voice(self, _network, _src_sub, _dst_sub, _ts, _end, _peerid, _data):
        logger.debug('(%s) Private Voice Packet Received From: %s, IPSC Peer %s, Destination %s', _network, int_id(_src_sub), int_id(_peerid), int_id(_dst_sub))
    
    def group_data(self, _network, _src_sub, _dst_sub, _ts, _end, _peerid, _data):    
        logger.debug('(%s) Group Data Packet Received From: %s, IPSC Peer %s, Destination %s', _network, int_id(_src_sub), int_id(_peerid), int_id(_dst_sub))
    
    def private_data(self, _network, _src_sub, _dst_sub, _ts, _end, _peerid, _data):    
        logger.debug('(%s) Private Data Packet Received From: %s, IPSC Peer %s, Destination %s', _network, int_id(_src_sub), int_id(_peerid), int_id(_dst_sub))

    def unknown_message(self, _network, _packettype, _peerid, _data):
        logger.error('(%s) Unknown Message - Type: %s From: %s Packet: %s', _network, h(_packettype), int_id(_peerid), h(_data))


    #************************************************
    #     IPSC SPECIFIC MAINTENANCE FUNCTIONS
    #************************************************
    
    # Simple function to send packets - handy to have it all in one place for debugging
    #
    def send_packet(self, _packet, (_host, _port)):
        self.transport.write(_packet, (_host, _port))
        # USE THE FOLLOWING ONLY UNDER DIRE CIRCUMSTANCES -- PERFORMANCE IS ADVERSLY AFFECTED!
        #logger.debug('(%s) TX Packet to %s on port %s: %s', self._network, _host, _port, h(_packet))
        
    # Accept a complete packet, ready to be sent, and send it to all active peers + master in an IPSC
    #
    def send_to_ipsc(self, _packet):
        # Send to the Master
        if self._master['STATUS']['CONNECTED']:
            self.send_packet(_packet, (self._master['IP'], self._master['PORT']))
        # Send to each connected Peer
        for peer in self._peers.keys():
            if self._peers[peer]['STATUS']['CONNECTED']:
                self.send_packet(_packet, (self._peers[peer]['IP'], self._peers[peer]['PORT']))
        
    
    # FUNTIONS FOR IPSC MAINTENANCE ACTIVITIES WE RESPOND TO
    
    # SOMEONE HAS SENT US A KEEP ALIVE - WE MUST ANSWER IT
    def peer_alive_req(self, _data, _peerid, _host, _port):
        _hex_mode      = (_data[5])
        _hex_flags     = (_data[6:10])
        _decoded_mode  = process_mode_byte(_hex_mode)
        _decoded_flags = process_flags_bytes(_hex_flags)
    
        self._peers[_peerid]['MODE'] = _hex_mode
        self._peers[_peerid]['MODE_DECODE'] = _decoded_mode
        self._peers[_peerid]['FLAGS'] = _hex_flags
        self._peers[_peerid]['FLAGS_DECODE'] = _decoded_flags
        # Generate a hashed packet from our template and send it.
        peer_alive_reply_packet = self.hashed_packet(self._local['AUTH_KEY'], self.PEER_ALIVE_REPLY_PKT)
        self.send_packet(peer_alive_reply_packet, (_host, _port))
        self.reset_keep_alive(_peerid)  # Might as well reset our own counter, we know it's out there...
        logger.debug('(%s) Keep-Alive reply sent to Peer %s, %s:%s', self._network, int_id(_peerid), _host, _port)

    # SOMEONE WANTS TO REGISTER WITH US - WE'RE COOL WITH THAT
    def peer_reg_req(self, _peerid, _host, _port):
        peer_reg_reply_packet = self.hashed_packet(self._local['AUTH_KEY'], self.PEER_REG_REPLY_PKT)
        self.send_packet(peer_reg_reply_packet, (_host, _port))
        logger.info('(%s) Peer Registration Request From: %s, %s:%s', self._network, int_id(_peerid), _host, _port)


    # SOMEONE HAS ANSWERED OUR KEEP-ALIVE REQUEST - KEEP TRACK OF IT
    def peer_alive_reply(self, _peerid):
        self.reset_keep_alive(_peerid)
        self._peers[_peerid]['STATUS']['KEEP_ALIVES_RECEIVED'] += 1
        self._peers[_peerid]['STATUS']['KEEP_ALIVE_RX_TIME'] = int(time())
        logger.debug('(%s) Keep-Alive Reply (we sent the request) Received from Peer %s, %s:%s', self._network, int_id(_peerid), self._peers[_peerid]['IP'], self._peers[_peerid]['PORT'])
    
    # SOMEONE HAS ANSWERED OUR REQEST TO REGISTER WITH THEM - KEEP TRACK OF IT
    def peer_reg_reply(self, _peerid):
        if _peerid in self._peers.keys():
            self._peers[_peerid]['STATUS']['CONNECTED'] = True
            logger.info('(%s) Registration Reply From: %s, %s:%s', self._network, int_id(_peerid), self._peers[_peerid]['IP'], self._peers[_peerid]['PORT'])
    
    # OUR MASTER HAS ANSWERED OUR KEEP-ALIVE REQUEST - KEEP TRACK OF IT
    def master_alive_reply(self, _peerid):
        self.reset_keep_alive(_peerid)
        self._master['STATUS']['KEEP_ALIVES_RECEIVED'] += 1
        self._master['STATUS']['KEEP_ALIVE_RX_TIME'] = int(time())
        logger.debug('(%s) Keep-Alive Reply (we sent the request) Received from the Master %s, %s:%s', self._network, int_id(_peerid), self._master['IP'], self._master['PORT'])
    
    # OUR MASTER HAS SENT US A PEER LIST - PROCESS IT
    def peer_list_reply(self, _data, _peerid):
        NETWORK[self._network]['MASTER']['STATUS']['PEER_LIST'] = True
        if len(_data) > 18:
            process_peer_list(_data, self._network)
        logger.debug('(%s) Peer List Reply Recieved From Master %s, %s:%s', self._network, int_id(_peerid), self._master['IP'], self._master['PORT'])
    
    # OUR MASTER HAS ANSWERED OUR REQUEST TO REGISTER - LOTS OF INFORMATION TO TRACK
    def master_reg_reply(self, _data, _peerid):
        _hex_mode      = _data[5]
        _hex_flags     = _data[6:10]
        _num_peers     = _data[10:12]
        _decoded_mode  = process_mode_byte(_hex_mode)
        _decoded_flags = process_flags_bytes(_hex_flags)
        
        self._local['NUM_PEERS'] = int(h(_num_peers), 16)
        self._master['RADIO_ID'] = _peerid
        self._master['MODE'] = _hex_mode
        self._master['MODE_DECODE'] = _decoded_mode
        self._master['FLAGS'] = _hex_flags
        self._master['FLAGS_DECODE'] = _decoded_flags
        self._master_stat['CONNECTED'] = True
        self._master_stat['KEEP_ALIVES_OUTSTANDING'] = 0
        logger.warning('(%s) Registration response (we requested reg) from the Master: %s, %s:%s (%s peers)', self._network, int_id(_peerid), self._master['IP'], self._master['PORT'], self._local['NUM_PEERS'])
    
    # WE ARE MASTER AND SOMEONE HAS REQUESTED REGISTRATION FROM US - ANSWER IT
    def master_reg_req(self, _data, _peerid, _host, _port):
        _ip_address    = _host
        _port          = _port
        _hex_mode      = _data[5]
        _hex_flags     = _data[6:10]
        _decoded_mode  = process_mode_byte(_hex_mode)
        _decoded_flags = process_flags_bytes(_hex_flags)
        
        self.MASTER_REG_REPLY_PKT = (MASTER_REG_REPLY + self._local_id + self.TS_FLAGS + hex_str_2(self._local['NUM_PEERS']) + IPSC_VER)
        
        master_reg_reply_packet = self.hashed_packet(self._local['AUTH_KEY'], self.MASTER_REG_REPLY_PKT)
        self.send_packet(master_reg_reply_packet, (_host, _port))
        logger.info('(%s) Master Registration Packet Received from peer %s, %s:%s', self._network, int_id(_peerid), _host, _port)

        # If this entry was NOT already in our list, add it.
        if _peerid not in self._peers.keys():
            self._peers[_peerid] = {
                'IP':          _ip_address, 
                'PORT':        _port, 
                'MODE':        _hex_mode,            
                'MODE_DECODE': _decoded_mode,
                'FLAGS':       _hex_flags,
                'FLAGS_DECODE': _decoded_flags,
                'STATUS': {
                    'CONNECTED':               True,
                    'KEEP_ALIVES_SENT':        0,
                    'KEEP_ALIVES_MISSED':      0,
                    'KEEP_ALIVES_OUTSTANDING': 0,
                    'KEEP_ALIVES_RECEIVED':    0,
                    'KEEP_ALIVE_RX_TIME':      int(time())
                    }
                }
        self._local['NUM_PEERS'] = len(self._peers)       
        logger.debug('(%s) Peer Added To Peer List: %s, %s:%s (IPSC now has %s Peers)', self._network, self._peers[_peerid], _host, _port, self._local['NUM_PEERS'])
    
    # WE ARE MASTER AND SOEMONE SENT US A KEEP-ALIVE - ANSWER IT, TRACK IT
    def master_alive_req(self, _peerid, _host, _port):
        if _peerid in self._peers.keys():
            self._peers[_peerid]['STATUS']['KEEP_ALIVES_RECEIVED'] += 1
            self._peers[_peerid]['STATUS']['KEEP_ALIVE_RX_TIME'] = int(time())
            
            master_alive_reply_packet = self.hashed_packet(self._local['AUTH_KEY'], self.MASTER_ALIVE_REPLY_PKT)
            self.send_packet(master_alive_reply_packet, (_host, _port))
            
            logger.debug('(%s) Master Keep-Alive Request Received from peer %s, %s:%s', self._network, int_id(_peerid), _host, _port)
        else:
            logger.warning('(%s) Master Keep-Alive Request Received from *UNREGISTERED* peer %s, %s:%s', self._network, int_id(_peerid), _host, _port)
    
    # WE ARE MASTER AND A PEER HAS REQUESTED A PEER LIST - SEND THEM ONE
    def peer_list_req(self, _peerid):
        if _peerid in self._peers.keys():
            logger.debug('(%s) Peer List Request from peer %s', self._network, int_id(_peerid))
            peer_list_packet = self.PEER_LIST_REPLY_PKT + build_peer_list(self._peers)
            peer_list_packet = self.hashed_packet(self._local['AUTH_KEY'], peer_list_packet)
            self.send_to_ipsc(peer_list_packet)
        else:
            logger.warning('(%s) Peer List Request Received from *UNREGISTERED* peer %s', self._network, int_id(_peerid))

    
    # Reset the outstanding keep-alive counter for _peerid...
    # Used when receiving acks OR when we see traffic from a repeater, since they ignore keep-alives when transmitting
    #
    def reset_keep_alive(self, _peerid):
        if _peerid in self._peers.keys():
            self._peers[_peerid]['STATUS']['KEEP_ALIVES_OUTSTANDING'] = 0
            self._peers[_peerid]['STATUS']['KEEP_ALIVE_RX_TIME'] = int(time())
        if _peerid == self._master['RADIO_ID']:
            self._master_stat['KEEP_ALIVES_OUTSTANDING'] = 0


    # THE NEXT SECTION DEFINES FUNCTIONS THAT MUST BE DIFFERENT FOR HASHED AND UNHASHED PACKETS
    # HASHED MEANS AUTHENTICATED IPSC
    # UNHASHED MEANS UNAUTHENTICATED IPSC

    # NEXT THREE FUNCITONS ARE FOR AUTHENTICATED PACKETS
    
    # Take a packet to be SENT, calculate auth hash and return the whole thing
    #
    def auth_hashed_packet(self, _key, _data):
        _hash = binascii.a2b_hex((hmac_new(_key,_data,sha1)).hexdigest()[:20])
        return _data + _hash
    
    # Remove the hash from a packet and return the payload
    #
    def auth_strip_hash(self, _data):
        return _data[:-10]
    
    # Take a RECEIVED packet, calculate the auth hash and verify authenticity
    #
    def auth_validate_auth(self, _key, _data):
        _payload = self.strip_hash(_data)
        _hash = _data[-10:]
        _chk_hash = binascii.a2b_hex((hmac_new(_key,_payload,sha1)).hexdigest()[:20])   

        if _chk_hash == _hash:
            return True
        else:
            return False
    
    # NEXT THREE FUNCITONS ARE FOR UN-AUTHENTICATED PACKETS
    
    # There isn't a hash to build, so just return the data
    #
    def unauth_hashed_packet(self, _key, _data):
        return _data
    
    # Remove the hash from a packet and return the payload... except don't
    #
    def unauth_strip_hash(self, _data):
        return _data
    
    # Everything is validated, so just return True
    #
    def unauth_validate_auth(self, _key, _data):
        return True


    #************************************************
    #     TIMED LOOP - CONNECTION MAINTENANCE
    #************************************************

    # Timed loop initialization (called by the twisted reactor)
    #       
    def startProtocol(self):
        # Timed loops for:
        #   IPSC connection establishment and maintenance
        #   Reporting/Housekeeping
        #
        # IF WE'RE NOT THE MASTER...
        if not self._local['MASTER_PEER']:
            self._peer_maintenance = task.LoopingCall(self.peer_maintenance_loop)
            self._peer_maintenance_loop = self._peer_maintenance.start(self._local['ALIVE_TIMER'])
        #
        # IF WE ARE THE MASTER...
        if self._local['MASTER_PEER']:
            self._master_maintenance = task.LoopingCall(self.master_maintenance_loop)
            self._master_maintenance_loop = self._master_maintenance.start(self._local['ALIVE_TIMER'])

    
    # Timed loop used for IPSC connection Maintenance when we are the MASTER
    #    
    def master_maintenance_loop(self):
        logger.debug('(%s) MASTER Connection Maintenance Loop Started', self._network)
        update_time = int(time())
        
        for peer in self._peers.keys():
            keep_alive_delta = update_time - self._peers[peer]['STATUS']['KEEP_ALIVE_RX_TIME']
            logger.debug('(%s) Time Since Last KeepAlive Request from Peer %s: %s seconds', self._network, int_id(peer), keep_alive_delta)
          
            if keep_alive_delta > 120:
                de_register_peer(self._network, peer)
                peer_list_packet = self.PEER_LIST_REPLY_PKT + build_peer_list(self._peers)
                peer_list_packet = self.hashed_packet(self._local['AUTH_KEY'], peer_list_packet)
                self.send_to_ipsc(peer_list_packet)
                logger.warning('(%s) Timeout Exceeded for Peer %s, De-registering', self._network, int_id(peer))
    
    # Timed loop used for IPSC connection Maintenance when we are a PEER
    #
    def peer_maintenance_loop(self):
        logger.debug('(%s) PEER Connection Maintenance Loop Started', self._network)

        # If the master isn't connected, we have to do that before we can do anything else!
        #
        if not self._master_stat['CONNECTED']:
            reg_packet = self.hashed_packet(self._local['AUTH_KEY'], self.MASTER_REG_REQ_PKT)
            self.send_packet(reg_packet, self._master_sock)
            logger.info('(%s) Registering with the Master: %s:%s', self._network, self._master['IP'], self._master['PORT'])
        
        # Once the master is connected, we have to send keep-alives.. and make sure we get them back
        elif self._master_stat['CONNECTED']:
            # Send keep-alive to the master
            master_alive_packet = self.hashed_packet(self._local['AUTH_KEY'], self.MASTER_ALIVE_PKT)
            self.send_packet(master_alive_packet, self._master_sock)
            logger.debug('(%s) Keep Alive Sent to the Master: %s, %s:%s', self._network, int_id(self._master['RADIO_ID']) ,self._master['IP'], self._master['PORT'])
            
            # 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
                logger.info('(%s) Master Keep-Alive Missed: %s:%s', self._network, self._master['IP'], self._master['PORT'])
            
            # If we have missed too many keep-alives, de-register the master and start over.
            if self._master_stat['KEEP_ALIVES_OUTSTANDING'] >= self._local['MAX_MISSED']:
                self._master_stat['CONNECTED'] = False
                self._master_stat['KEEP_ALIVES_OUTSTANDING'] = 0
                logger.error('(%s) Maximum Master Keep-Alives Missed -- De-registering the Master: %s:%s', self._network, self._master['IP'], self._master['PORT'])
            
            # 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, we need to reset the state and try again
            logger.error('->> (%s) Master in UNKOWN STATE: %s:%s', self._network, self._master_sock)
            self._master_stat['CONNECTED'] = False
        
        
        # 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
            if self._local['NUM_PEERS']:
                peer_list_req_packet = self.hashed_packet(self._local['AUTH_KEY'], self.PEER_LIST_REQ_PKT)
                self.send_packet(peer_list_req_packet, self._master_sock)
                logger.info('(%s), No Peer List - Requesting One From the Master', self._network)
            else:
                self._master_stat['PEER_LIST'] = True
                logger.debug('(%s), Skip asking for a Peer List, we are the only Peer', self._network)


        # If we do have a peer-list, we need to register with the peers and send keep-alives...
        #
        if self._master_stat['PEER_LIST']:
            # Iterate the list of peers... so we do this for each one.
            for peer in self._peers.keys():

                # We will show up in the peer list, but shouldn't try to talk to ourselves.
                if peer == self._local_id:
                    continue

                # If we haven't registered to a peer, send a registration
                if not self._peers[peer]['STATUS']['CONNECTED']:
                    peer_reg_packet = self.hashed_packet(self._local['AUTH_KEY'], self.PEER_REG_REQ_PKT)
                    self.send_packet(peer_reg_packet, (self._peers[peer]['IP'], self._peers[peer]['PORT']))
                    logger.info('(%s) Registering with Peer %s, %s:%s', self._network, int_id(peer), self._peers[peer]['IP'], self._peers[peer]['PORT'])

                # If we have registered with the peer, then send a keep-alive
                elif self._peers[peer]['STATUS']['CONNECTED']:
                    peer_alive_req_packet = self.hashed_packet(self._local['AUTH_KEY'], self.PEER_ALIVE_REQ_PKT)
                    self.send_packet(peer_alive_req_packet, (self._peers[peer]['IP'], self._peers[peer]['PORT']))
                    logger.debug('(%s) Keep-Alive Sent to the Peer %s, %s:%s', self._network, int_id(peer), self._peers[peer]['IP'], self._peers[peer]['PORT'])

                    # If we have a keep-alive outstanding by the time we send another, mark it missed.
                    if self._peers[peer]['STATUS']['KEEP_ALIVES_OUTSTANDING'] > 0:
                        self._peers[peer]['STATUS']['KEEP_ALIVES_MISSED'] += 1
                        logger.info('(%s) Peer Keep-Alive Missed for %s, %s:%s', self._network, int_id(peer), self._peers[peer]['IP'], self._peers[peer]['PORT'])

                    # If we have missed too many keep-alives, de-register the peer and start over.
                    if self._peers[peer]['STATUS']['KEEP_ALIVES_OUTSTANDING'] >= self._local['MAX_MISSED']:
                        self._peers[peer]['STATUS']['CONNECTED'] = False
                        #del peer   # Becuase once it's out of the dictionary, you can't use it for anything else.
                        logger.warning('(%s) Maximum Peer Keep-Alives Missed -- De-registering the Peer: %s, %s:%s', self._network, int_id(peer), self._peers[peer]['IP'], self._peers[peer]['PORT'])
                    
                    # Update our stats before moving on...
                    self._peers[peer]['STATUS']['KEEP_ALIVES_SENT'] += 1
                    self._peers[peer]['STATUS']['KEEP_ALIVES_OUTSTANDING'] += 1
    


    #************************************************
    #     MESSAGE RECEIVED - TAKE ACTION
    #************************************************

    # Actions for received packets by type: For every packet received, 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 processing or callbacks for each packet type.
    #
    # Callbacks are iterated in the order of "more likely" to "less likely" to reduce processing time
    #
    def datagramReceived(self, data, (host, port)):

        # Loop timing test, uncomment the next two lines. Use for testing only.
        #_pkt_id = randint(0,10000)
        #_pkt_time = time()

        _packettype = data[0:1]
        _peerid     = data[1:5]
        _ipsc_seq   = data[5:6]
        
        # AUTHENTICATE THE PACKET
        if not self.validate_auth(self._local['AUTH_KEY'], data):
            logger.warning('(%s) AuthError: IPSC packet failed authentication. Type %s: Peer: %s, %s:%s', self._network, h(_packettype), int_id(_peerid), host, port)
            return
            
        # REMOVE SHA-1 AUTHENTICATION HASH: WE NO LONGER NEED IT
        data = self.strip_hash(data)

        # PACKETS THAT WE RECEIVE FROM ANY VALID PEER OR VALID MASTER
        if _packettype in ANY_PEER_REQUIRED:
            if not(valid_master(self._network, _peerid) == False or valid_peer(self._peers.keys(), _peerid) == False):
                logger.warning('(%s) PeerError: Peer not in peer-list: %s, %s:%s', self._network, int_id(_peerid), host, port)
                return
                
            # ORIGINATED BY SUBSCRIBER UNITS - a.k.a someone transmitted
            if _packettype in USER_PACKETS:
                # Extract IPSC header not already extracted
                _src_sub    = data[6:9]
                _dst_sub    = data[9:12]
                _call_type  = data[12:13]
                _unknown_1  = data[13:17]
                _call_info  = int_id(data[17:18])                
                _ts         = bool(_call_info & TS_CALL_MSK)
                _end        = bool(_call_info & END_MSK)
                
                # Extract RTP Header Fields
                '''
                Coming soon kids!!!
                Looks like version, padding, extention, CSIC, payload type and SSID never change.
                The things we might care about are below.
                _rtp_byte_1 = int_id(data[18:19])
                _rtp_byte_2 = int_id(data[19:20])
                _rtp_seq    = int_id(data[20:22])
                _rtp_tmstmp = int_id(data[22:26])
                _rtp_ssid = int_id(data[26:30])
                
                # Extract RTP Payload Data Fields
                _payload_type = int_id(data[30:31])
                '''

                # User Voice and Data Call Types:
                if _packettype == GROUP_VOICE:
                    self.reset_keep_alive(_peerid)
                    self.group_voice(self._network, _src_sub, _dst_sub, _ts, _end, _peerid, data)
                    
                    # Loop timing test, uncomment the next two lines. Use for testing only.
                    #_pkt_proc_time = (time() - _pkt_time) * 1000
                    #logger.info('TIMING: Group voice packet ID %s took %s ms', _pkt_id, _pkt_proc_time)
                    
                    return
            
                elif _packettype == PVT_VOICE:
                    self.reset_keep_alive(_peerid)
                    self.private_voice(self._network, _src_sub, _dst_sub, _ts, _end, _peerid, data)
                    return
                    
                elif _packettype == GROUP_DATA:
                    self.reset_keep_alive(_peerid)
                    self.group_data(self._network, _src_sub, _dst_sub, _ts, _end, _peerid, data)
                    return
                    
                elif _packettype == PVT_DATA:
                    self.reset_keep_alive(_peerid)
                    self.private_data(self._network, _src_sub, _dst_sub, _ts, _end, _peerid, data)
                    return
                return
                
            # MOTOROLA XCMP/XNL CONTROL PROTOCOL: We don't process these (yet)   
            elif _packettype == XCMP_XNL:
                self.xcmp_xnl(self._network, data)
                return
            
            # ORIGINATED BY PEERS, NOT IPSC MAINTENANCE: Call monitoring is all we've found here so far 
            elif _packettype == CALL_MON_STATUS:
                self.call_mon_status(self._network, data)
                return
                
            elif _packettype == CALL_MON_RPT:
                self.call_mon_rpt(self._network, data)
                return
                
            elif _packettype == CALL_MON_NACK:
                self.call_mon_nack(self._network, data)
                return
                
            # IPSC CONNECTION MAINTENANCE MESSAGES
            elif _packettype == DE_REG_REQ:
                de_register_peer(self._network, _peerid)
                logger.warning('(%s) Peer De-Registration Request From: %s, %s:%s', self._network, int_id(_peerid), host, port)
                return
            
            elif _packettype == DE_REG_REPLY:
                logger.warning('(%s) Peer De-Registration Reply From: %s, %s:%s', self._network, int_id(_peerid), host, port)
                return
                
            elif _packettype == RPT_WAKE_UP:
                self.repeater_wake_up(self._network, data)
                logger.debug('(%s) Repeater Wake-Up Packet From: %s, %s:%s', self._network, int_id(_peerid), host, port)
                return
            return

        #
        # THE FOLLOWING PACKETS ARE RECEIVED ONLY IF WE ARE OPERATING AS A PEER
        #
        
        # ONLY ACCEPT FROM A PREVIOUSLY VALIDATED PEER
        if _packettype in PEER_REQUIRED:
            if not valid_peer(self._peers.keys(), _peerid):
                logger.warning('(%s) PeerError: Peer not in peer-list: %s, %s:%s', self._network, int_id(_peerid), host, port)
                return
            
            # REQUESTS FROM PEERS: WE MUST REPLY IMMEDIATELY FOR IPSC MAINTENANCE
            if _packettype == PEER_ALIVE_REQ:
                self.peer_alive_req(data, _peerid, host, port)
                return
                                
            elif _packettype == PEER_REG_REQ:
                self.peer_reg_req(_peerid, host, port)
                return
                
            # ANSWERS FROM REQUESTS WE SENT TO PEERS: WE DO NOT REPLY
            elif _packettype == PEER_ALIVE_REPLY:
                self.peer_alive_reply(_peerid)
                return                

            elif _packettype == PEER_REG_REPLY:
                self.peer_reg_reply(_peerid)
                return
            return
            
        
        # PACKETS ONLY ACCEPTED FROM OUR MASTER
        
        # PACKETS WE ONLY ACCEPT IF WE HAVE FINISHED REGISTERING WITH OUR MASTER
        if _packettype in MASTER_REQUIRED:
            if not valid_master(self._network, _peerid):
                logger.warning('(%s) MasterError: %s, %s:%s is not the master peer', self._network, int_id(_peerid), host, port)
                return
            
            # ANSWERS FROM REQUESTS WE SENT TO THE MASTER: WE DO NOT REPLY    
            if _packettype == MASTER_ALIVE_REPLY:
                self.master_alive_reply(_peerid)
                return
            
            elif _packettype == PEER_LIST_REPLY:
                self.peer_list_reply(data, _peerid)
                return
            return
            
        
        # THIS MEANS WE HAVE SUCCESSFULLY REGISTERED TO OUR MASTER - RECORD MASTER INFORMATION
        elif _packettype == MASTER_REG_REPLY:
            self.master_reg_reply(data, _peerid)
            return
        

        # THE FOLLOWING PACKETS ARE RECEIVED ONLLY IF WE ARE OPERATING AS A MASTER
        
        # REQUESTS FROM PEERS: WE MUST REPLY IMMEDIATELY FOR IPSC MAINTENANCE
        
        # REQUEST TO REGISTER TO THE IPSC
        elif _packettype == MASTER_REG_REQ:
            self.master_reg_req(data, _peerid, host, port)           
            return
          
        # REQUEST FOR A KEEP-ALIVE REPLY (WE KNOW THE PEER IS STILL ALIVE TOO) 
        elif _packettype == MASTER_ALIVE_REQ:
            self.master_alive_req(_peerid, host, port)
            return
            
        # REQUEST FOR A PEER LIST
        elif _packettype == PEER_LIST_REQ:
            self.peer_list_req(_peerid)
            return
            
             
        
        # PACKET IS OF AN UNKNOWN TYPE. LOG IT AND IDENTTIFY IT!
        else:
            self.unknown_message(self._network, _packettype, _peerid, data)
            return

    

#************************************************
#      MAIN PROGRAM LOOP STARTS HERE
#************************************************

if __name__ == '__main__':
    logger.info('DMRlink \'dmrlink.py\' (c) 2013 - 2015 N0MJS & the K0USY Group - SYSTEM STARTING...')
    
    # INITIALIZE AN IPSC OBJECT (SELF SUSTAINING) FOR EACH CONFIGUED IPSC
    networks = {}
    for ipsc_network in NETWORK:
        if NETWORK[ipsc_network]['LOCAL']['ENABLED']:
            networks[ipsc_network] = IPSC(ipsc_network)
            reactor.listenUDP(NETWORK[ipsc_network]['LOCAL']['PORT'], networks[ipsc_network], interface=NETWORK[ipsc_network]['LOCAL']['IP'])
  
    # INITIALIZE THE REPORTING LOOP IF CONFIGURED
    if REPORTS['REPORT_NETWORKS']:
        reporting = task.LoopingCall(reporting_loop)
        reporting.start(REPORTS['REPORT_INTERVAL'])
  
    reactor.run()