meshenger/main.py

#!/usr/bin/python

import socket, os, time, select, urllib, sys, threading, json, logging, logging.config

os.chdir(os.path.dirname(__file__)) # change present working directory to the one where this file is

logging.config.fileConfig('pylog.conf')
logger = logging.getLogger('meshenger'+'.main')

class Meshenger:
  devices = {} #the dictionary of all the nodes this this node has seen. each ip-entry has a tuple of 'foreign index update time' and time when last seen
  devices_old =  {}
  serve_port = "13338"
  announce_port = 13337
  #own_ip = "0.0.0.0"
  msg_dir = os.path.relpath('msg/')
  exitapp = False #to kill all threads on
  index_last_update = str(int(time.time()))
  node_expiry = 15 #the time to wait before removing a node form the discovered nodelist

  def __init__(self):

    os.system("echo 1 >> /proc/sys/net/ipv6/conf/br-lan/disable_ipv6")
    os.system("echo 1 >> /proc/sys/net/ipv6/conf/br-hotspot/disable_ipv6")


    self.own_ip = self.get_ip_adress().strip()
    # this hash is needed in clientserve, so client can generate color
    self.own_hash = self.hasj(self.own_ip)

    if not os.path.exists(self.msg_dir):
      os.mkdir(self.msg_dir)
      logger.info('Making message directory')

    self.init_index()
    self.make_alias()

    try:
      d = threading.Thread(target=self.discover)
      d.daemon = True
      d.start()

      a = threading.Thread(target=self.announce)
      a.daemon = True
      a.start()

      n = threading.Thread(target=self.nodeserve)
      n.daemon = True
      n.start()

      c = threading.Thread(target=self.clientserve)
      c.daemon = True
      c.start()

    except (KeyboardInterrupt, SystemExit):
      logger.info('exiting discovery thread')
      d.join()
      a.join()
      b.join()
      n.join()
      c.join()
      sys.exit()
    except Exception as e:
      logger.warning( 'Main __init__ thread exception: %s', repr(e) )
    except:
      logger.warning( 'Main __init__ unknown thread exception')

    while True:
      logger.debug('Entering main loop')
      #
      if len(self.devices) > 0:
        logger.info('found %s device(s)', len(self.devices))

        for device in self.devices.keys():
          nodehash = self.hasj(device)
          nodepath = os.path.join(os.path.abspath('nodes'), nodehash)
          nodeupdatepath = os.path.join(nodepath, 'lastupdate')

          logger.info('Checking age of foreign node index')
          logger.info('%s Foreign announce timestamp', self.devices[device])
          try:
            foreign_node_update = open(nodeupdatepath).read()
          except:
            foreign_node_update = 0 #means it was never seen before

          logger.info('%s Locally stored timestamp for device', foreign_node_update)


          if self.devices[device] > foreign_node_update:
            logger.info('Foreign node"s index is newer, proceed to download index')
            self.get_index(device, nodepath)
            logger.info('downloading messages')
            self.get_messages(device, nodepath, nodehash)
            self.build_index()
          self.node_timestamp(device)

      self.devices_old = dict(self.devices)

      #check to see if a node has been missing for a while, if so remove it from self.devices
      for device in self.devices_old.keys(): 
        update_time = int(self.devices[device][1])
        time_delta = int(time.time())- update_time
        if time_delta >= self.node_expiry:
          logger.info('Node '+device+' missing for '+str(self.node_expiry)+' seconds. Removing from list')
          del self.devices[device]

      time.sleep(5) #free process or ctrl+c


  def node_timestamp(self, ip):
      nodepath = os.path.abspath(os.path.join('nodes', self.hasj(ip)))
      updatepath = os.path.join(nodepath, 'lastupdate')
      with open(updatepath, 'wb') as lastupdate:
        lastupdate.write(self.devices[ip][0])
      #return updatepath



  def announce(self):
    """
Announce the node's existance to other nodes
"""
    logger.info('Announcing')
    while not self.exitapp:
      try:
        sock = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
        sock.sendto(self.index_last_update, ("ff02::1", self.announce_port))
        #sock.close()
        time.sleep(5)
      except:
        logger.warning('Failed to announce myself!')

  def discover(self):
    """
Discover other devices by listening to the Meshenger announce port
"""

    logger.info('Discovering')
    bufferSize = 1024 # whatever you need?

    s = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
    s.bind(('::', self.announce_port))
    s.setblocking(0)
    while not self.exitapp:
      result = select.select([s],[],[])[0][0].recvfrom(bufferSize)
      ip = result[1][0]
      #logger.debug('%s %s', ip, 'discovered')
      node_path = os.path.join(os.path.abspath('nodes'), self.hasj(ip))
      announce_time = str(int(time.time()))
      if not os.path.exists(node_path) and ip != self.own_ip: 
        #loop for first time
        self.ip_to_hash_path(ip) #make a folder /nodes/hash
        self.devices[ip] = result[0], announce_time
        #self.node_timestamp(ip) #make a local copy of the timestamp in /nodes/hash/updatetimestamp
        logger.info('New node %s', ip)

      elif os.path.exists(node_path) and ip != self.own_ip:
        logger.info('Known node %s', ip)
        self.devices[ip] = result[0], announce_time


      time.sleep(1)

  def nodeserve(self):
    """
Initialize the nodeserver
"""
    logger.info('Serving to nodes')
    import meshenger_nodeserve
    meshenger_nodeserve.main()

  def clientserve(self):
    """
Initialize the clientserver
"""
    logger.info('Serving to client')
    import meshenger_clientserve
    # set a reference to this object 
    meshenger_clientserve.meshenger = self
    meshenger_clientserve.main()
    # meshenger_clientserve.build_index_callback = self.build_index

  def init_index(self):
    """
Initialize the index. Read from disk or create new.
"""
    logger.info('Checking own index for the first time\n')

    if not os.path.exists('index'):
      with open('index','wb') as index:
        index.write('')
      self.previous_index = []
    else:
      self.previous_index = open('index').readlines()
      self.build_index()

  def build_index(self):
    """
	Make an index file of all the messages present on the node.
	Save the time of the last update.
	"""
    logger.debug('build_index')
    current_index = os.listdir(self.msg_dir)
    if current_index != self.previous_index:
      with open('index', 'wb') as index:
        for message in os.listdir(self.msg_dir):
          index.write(message)
          index.write('\n')
      self.index_last_update = str(int(time.time()))

      logger.info('Index updated: %s', current_index)

      with open('index_last_update', 'wb') as indexupdate:
        indexupdate.write(self.index_last_update) ### misschien moet dit index_last_update zijn

    self.previous_index = current_index

  def make_alias(self):
	"""
	See if the node already has an alias (nickname) if not just use the IP-Hash
	"""
	if not os.path.exists('alias'):
	  with open('alias','wb') as alias:
		self.alias = self.own_hash
		alias.write(self.own_hash)
	else:
	  self.alias = open('alias','rb').read().replace('\n','') #should we replace the newline?
	  pass
	logger.debug('Alias is "'+self.alias+'"')


  def get_index(self,ip, path):
    """
	Download the indices from other nodes.
	"""

    os.system('wget http://['+ip+'%adhoc0]:'+self.serve_port+'/index -O '+os.path.join(path,'index'))


  def get_messages(self, ip, path, hash):
    """
Get new messages from other node based on it's index file
"""
    try:
      with open(os.path.join(path,'index')) as index:
        index = index.read().split('\n')
        for message in index:
          messagepath = os.path.join(os.path.abspath(self.msg_dir), message)
          if not os.path.exists(messagepath):
            logger.info('downloading %s to %s', message, messagepath)
            os.system('wget http://['+ip+'%adhoc0]:'+self.serve_port+'/msg/'+message+' -O '+messagepath)
	    with open(messagepath, 'r+') as f:
		data=json.load(f)
	    	data['hops']=str(int(data['hops'])+1)
		data['node']=hash
	        f.seek(0)
		json.dump(data, f)
    except:
      logger.info('Failed to download messages')
      pass

  def ip_to_hash_path(self, ip):
    """
Convert a node's ip into a hash and make a directory to store it's files
"""
    if not os.path.exists('nodes'):
      os.mkdir('nodes')

    nodepath = os.path.join(os.path.abspath('nodes'), self.hasj(ip))
    if not os.path.exists(nodepath):
      os.mkdir(nodepath)

    return nodepath


  def hasj(self, ip):
        """
        Convert a node's ip into a hash
        """
        import hashlib
        hasj = hashlib.md5(ip).hexdigest()
        return hasj

  def get_ip_adress(self):
    """
Hack to adhoc0's inet6 adress
"""
    #TODO possibly check if it's an empty file 
    if not os.path.isfile('interfaceip6adress'):
      os.system('ifconfig -a adhoc0 | grep inet6 > /root/meshenger/interfaceip6adress')
    with open('/root/meshenger/interfaceip6adress', 'r') as a:
      return a.read().split()[2].split('/')[0]



if __name__ == "__main__":
  logger.info("starting main...")
  try:
    meshenger = Meshenger()
  except (KeyboardInterrupt, SystemExit):
    exitapp = True
    raise