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DMRlink/ipsc.py

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