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DMRlink/ipsc.py
Cort Buffington b41cf5ff7b CLEAN UP & DOCUMENT 
This was just a massive clean up and documentation festival. Many many
clean ups made for better readability and consistenty, most everything
is well commented now too.
2013-08-30 16:23:12 -05:00

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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
#************************************************
# 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):
# _log = logger.debug
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:
return True
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:
return True
else:
return False
# Take a packet to be SENT, calcualte auth hash and return the whole thing
#
def hashed_packet(_key, _data):
# _log = logger.debug
_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 = 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
# Forward Group Voice Packet
#
def fwd_group_voice(_network, _data):
# _log = logger.debug
_src_group = _data[9:12]
_src_ipsc = _data[1:5]
for source in NETWORK[_network]['RULES']['GROUP_VOICE']:
# Matching for rules is against the Destination Group in the SOURCE packet (SRC_GROUP)
if source['SRC_GROUP'] == _src_group:
_target = source['DST_NET']
_target_sock = NETWORK[_target]['MASTER']['IP'], NETWORK[_target]['MASTER']['PORT']
# Re-Write the IPSC SRC to match the target network's ID
_data = _data.replace(_src_ipsc, NETWORK[_target]['LOCAL']['RADIO_ID'])
# Re-Write the destinaion Group ID
_data = _data.replace(_src_group, source['DST_GROUP'])
# Calculate and append the authentication hash for the target network... if necessary
if NETWORK[_target]['LOCAL']['AUTH_KEY'] == True:
_data = hashed_packet(NETWORK[_target]['LOCAL']['AUTH_KEY'], _data)
# Send the packet to all peers in the target IPSC
send_to_ipsc(_target, _data)
# 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
networks[_target].transport.write(_packet, (NETWORK[_target]['MASTER']['IP'], NETWORK[_target]['MASTER']['PORT']))
# 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']))
# 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
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)
# 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 how many peers are in the list by parsing the packet
_num_peers = int(str(int(binascii.b2a_hex(_data[5:7]), 16))[1:])
# Record the number of peers in the data structure... we'll use it later.
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)
# Iterate each peer entry in the peer list. Skip the header, then pull the next peer, the next, etc.
for i in range(7, (_num_peers*11)+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.
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
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']).
# 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 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):
# 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 = 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 = 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 = 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 = 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 = 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
#************************************************
# 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 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
# Group voice callback function
fwd_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 = hashed_packet(self._local['AUTH_KEY'], self.PEER_ALIVE_REPLY_PKT)
self.transport.write(peer_alive_reply_packet, (host, port))
elif (_packettype == MASTER_ALIVE_REPLY):
# 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):
# TO DO TO DO TO DO TO DO ***ADD CODE TO VALIDATE THE PEER IS IN OUR PEER-LIST HERE***
# ***MAKE SURE WE CHECK TO SEE IF WE NEED TO MAKE AN AUTHENITCATED PACKET FIRST***
peer_reg_reply_packet = hashed_packet(self._local['AUTH_KEY'], self.PEER_REG_REPLY_PKT)
self.transport.write(peer_reg_reply_packet, (host, port))
elif (_packettype == PEER_REG_REPLY):
for peer in self._config['PEERS']:
if peer['RADIO_ID'] == _peerid:
peer['STATUS']['CONNECTED'] = True
elif (_packettype == PEER_LIST_REPLY):
self._peer_list = process_peer_list(data, self._network, self._peer_list)
# Other "user" related packet types that we don't do much or anything with yet
#
elif (_packettype == PVT_VOICE):
logger.warning('<<- (%s) Voice Packet From:%s:%s', self._network, host, port)
elif (_packettype == GROUP_DATA):
logger.warning('<<- (%s) Group Data Packet From:%s:%s', self._network, host, port)
elif (_packettype == PVT_DATA):
logger.warning('<<- (%s) Private Data Packet From From:%s:%s', self._network, host, port)
elif (_packettype == DE_REG_REQ):
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)
# Technically, we're not paying any attention to these types because we're not part of the XCMP call control structure
#
elif (_packettype == XCMP_XNL):
logger.warning('<<- (%s) XCMP_XNL From:%s:%s, but we did not indicate XCMP capable!', self._network, host, port)
elif (_packettype in (CALL_CTL_1, CALL_CTL_2, CALL_CTL_3)):
logger.warning('<<- (%s) Call Control Packet From:%s:%s', self._network, host, port)
# If there's a packet type we don't know aobut, it should be logged so we can figure it out and take an appropriate action!
else:
packet_type = binascii.b2a_hex(_packettype)
logger.error('<<- (%s) Received Unprocessed Type %s From:%s:%s', self._network, packet_type, host, port)
#************************************************
# MAIN PROGRAM LOOP STARTS HERE
#************************************************
if __name__ == '__main__':
networks = {}
for ipsc_network in NETWORK:
networks[ipsc_network] = IPSC(ipsc_network)
if (NETWORK[ipsc_network]['LOCAL']['ENABLED']):
reactor.listenUDP(NETWORK[ipsc_network]['LOCAL']['PORT'], networks[ipsc_network])
reactor.run()
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