import logging.config
import random
import socket
import struct
import threading
import os
from coapthon import defines
from coapthon.layers.blocklayer import BlockLayer
from coapthon.layers.cachelayer import CacheLayer
from coapthon.layers.forwardLayer import ForwardLayer
from coapthon.layers.messagelayer import MessageLayer
from coapthon.layers.observelayer import ObserveLayer
from coapthon.layers.resourcelayer import ResourceLayer
from coapthon.messages.message import Message
from coapthon.messages.request import Request
from coapthon.resources.resource import Resource
from coapthon.serializer import Serializer
from coapthon.utils import Tree, create_logging
__author__ = 'Giacomo Tanganelli'
if not os.path.isfile("logging.conf"):
create_logging()
logger = logging.getLogger(__name__)
logging.config.fileConfig("logging.conf", disable_existing_loggers=False)
[docs]class CoAP(object):
"""
Implementation of the Forward Proxy
"""
def __init__(self, server_address, multicast=False, starting_mid=None, cache=False, sock=None):
"""
Initialize the Forward Proxy.
:param server_address: Server address for incoming connections
:param multicast: if the ip is a multicast address
:param starting_mid: used for testing purposes
:param cache: if a cache must be used
:param sock: if a socket has been created externally, it can be used directly
"""
self.stopped = threading.Event()
self.stopped.clear()
self.to_be_stopped = []
self.purge = threading.Thread(target=self.purge)
self.purge.start()
self.cache_enable = cache
self._messageLayer = MessageLayer(starting_mid)
self._blockLayer = BlockLayer()
self._observeLayer = ObserveLayer()
if self.cache_enable:
self._cacheLayer = CacheLayer(defines.FORWARD_PROXY)
else:
self._cacheLayer = None
self._forwardLayer = ForwardLayer(self)
self.resourceLayer = ResourceLayer(self)
# Resource directory
root = Resource('root', self, visible=False, observable=False, allow_children=True)
root.path = '/'
self.root = Tree()
self.root["/"] = root
self._serializer = None
self.server_address = server_address
self.multicast = multicast
addrinfo = socket.getaddrinfo(self.server_address[0], None)[0]
if sock is not None:
# Use given socket, could be a DTLS socket
self._socket = sock
elif self.multicast: # pragma: no cover
# Create a socket
# self._socket.setsockopt(socket.SOL_IP, socket.IP_MULTICAST_TTL, 255)
# self._socket.setsockopt(socket.SOL_IP, socket.IP_MULTICAST_LOOP, 1)
# Join group
if addrinfo[0] == socket.AF_INET: # IPv4
self._socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
# Allow multiple copies of this program on one machine
# (not strictly needed)
self._socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
self._socket.bind((defines.ALL_COAP_NODES, self.server_address[1]))
mreq = struct.pack("4sl", socket.inet_aton(defines.ALL_COAP_NODES), socket.INADDR_ANY)
self._socket.setsockopt(socket.IPPROTO_IP, socket.IP_ADD_MEMBERSHIP, mreq)
self._unicast_socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
self._unicast_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
self._unicast_socket.bind(self.server_address)
else:
self._socket = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
# Allow multiple copies of this program on one machine
# (not strictly needed)
self._socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
self._socket.bind((defines.ALL_COAP_NODES_IPV6, self.server_address[1]))
addrinfo_multicast = socket.getaddrinfo(defines.ALL_COAP_NODES_IPV6, 5683)[0]
group_bin = socket.inet_pton(socket.AF_INET6, addrinfo_multicast[4][0])
mreq = group_bin + struct.pack('@I', 0)
self._socket.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_JOIN_GROUP, mreq)
self._unicast_socket = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM)
self._unicast_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
self._unicast_socket.bind(self.server_address)
else:
if addrinfo[0] == socket.AF_INET: # IPv4
self._socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
self._socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
else:
self._socket = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM)
self._socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
self._socket.bind(self.server_address)
[docs] def purge(self):
"""
Clean old transactions
"""
while not self.stopped.isSet():
self.stopped.wait(timeout=defines.EXCHANGE_LIFETIME)
self._messageLayer.purge()
[docs] def listen(self, timeout=10):
"""
Listen for incoming messages. Timeout is used to check if the server must be switched off.
:param timeout: Socket Timeout in seconds
"""
self._socket.settimeout(float(timeout))
while not self.stopped.isSet():
try:
data, client_address = self._socket.recvfrom(4096)
except socket.timeout:
continue
try:
#Start a new thread not to block other requests
args = ((data, client_address), )
t = threading.Thread(target=self.receive_datagram, args=args)
t.daemon = True
t.start()
except RuntimeError:
logging.exception("Exception with Executor")
logging.debug("closing socket")
self._socket.close()
[docs] def close(self):
"""
Stop the server.
"""
logger.info("Stop server")
self.stopped.set()
for event in self.to_be_stopped:
event.set()
self._socket.close()
[docs] def receive_datagram(self, args):
"""
Handle messages coming from the udp socket.
:param args: (data, client_address)
"""
data, client_address = args
logging.debug("receiving datagram")
try:
host, port = client_address
except ValueError:
host, port, tmp1, tmp2 = client_address
client_address = (host, port)
serializer = Serializer()
message = serializer.deserialize(data, client_address)
if isinstance(message, int):
logger.error("receive_datagram - BAD REQUEST")
rst = Message()
rst.destination = client_address
rst.type = defines.Types["RST"]
rst.code = message
self.send_datagram(rst)
return
logger.debug("receive_datagram - " + str(message))
if isinstance(message, Request):
transaction = self._messageLayer.receive_request(message)
if transaction.request.duplicated and transaction.completed:
logger.debug("message duplicated,transaction completed")
transaction = self._observeLayer.send_response(transaction)
transaction = self._blockLayer.send_response(transaction)
transaction = self._messageLayer.send_response(transaction)
self.send_datagram(transaction.response)
return
elif transaction.request.duplicated and not transaction.completed:
logger.debug("message duplicated,transaction NOT completed")
self._send_ack(transaction)
return
transaction.separate_timer = self._start_separate_timer(transaction)
transaction = self._blockLayer.receive_request(transaction)
if transaction.block_transfer:
self._stop_separate_timer(transaction.separate_timer)
transaction = self._messageLayer.send_response(transaction)
self.send_datagram(transaction.response)
return
transaction = self._observeLayer.receive_request(transaction)
"""
call to the cache layer to check if there's a cached response for the request
if not, call the forward layer
"""
if self._cacheLayer is not None:
transaction = self._cacheLayer.receive_request(transaction)
if transaction.cacheHit is False:
logging.debug(transaction.request)
transaction = self._forwardLayer.receive_request(transaction)
logging.debug(transaction.response)
transaction = self._observeLayer.send_response(transaction)
transaction = self._blockLayer.send_response(transaction)
transaction = self._cacheLayer.send_response(transaction)
else:
transaction = self._forwardLayer.receive_request(transaction)
transaction = self._observeLayer.send_response(transaction)
transaction = self._blockLayer.send_response(transaction)
self._stop_separate_timer(transaction.separate_timer)
transaction = self._messageLayer.send_response(transaction)
if transaction.response is not None:
if transaction.response.type == defines.Types["CON"]:
self._start_retransmission(transaction, transaction.response)
self.send_datagram(transaction.response)
elif isinstance(message, Message):
transaction = self._messageLayer.receive_empty(message)
if transaction is not None:
transaction = self._blockLayer.receive_empty(message, transaction)
self._observeLayer.receive_empty(message, transaction)
else: # is Response
logger.error("Received response from %s", message.source)
[docs] def send_datagram(self, message):
"""
Send a message through the udp socket.
:type message: Message
:param message: the message to send
"""
if not self.stopped.isSet():
host, port = message.destination
logger.debug("send_datagram - " + str(message))
serializer = Serializer()
message = serializer.serialize(message)
self._socket.sendto(message, (host, port))
def _start_retransmission(self, transaction, message):
"""
Start the retransmission task.
:type transaction: Transaction
:param transaction: the transaction that owns the message that needs retransmission
:type message: Message
:param message: the message that needs the retransmission task
"""
with transaction:
if message.type == defines.Types['CON']:
future_time = random.uniform(defines.ACK_TIMEOUT, (defines.ACK_TIMEOUT * defines.ACK_RANDOM_FACTOR))
transaction.retransmit_thread = threading.Thread(target=self._retransmit,
args=(transaction, message, future_time, 0))
transaction.retransmit_stop = threading.Event()
self.to_be_stopped.append(transaction.retransmit_stop)
transaction.retransmit_thread.start()
def _retransmit(self, transaction, message, future_time, retransmit_count):
"""
Thread function to retransmit the message in the future
:param transaction: the transaction that owns the message that needs retransmission
:param message: the message that needs the retransmission task
:param future_time: the amount of time to wait before a new attempt
:param retransmit_count: the number of retransmissions
"""
with transaction:
while retransmit_count < defines.MAX_RETRANSMIT and (not message.acknowledged and not message.rejected) \
and not self.stopped.isSet():
transaction.retransmit_stop.wait(timeout=future_time)
if not message.acknowledged and not message.rejected and not self.stopped.isSet():
retransmit_count += 1
future_time *= 2
self.send_datagram(message)
if message.acknowledged or message.rejected:
message.timeouted = False
else:
logger.warning("Give up on message {message}".format(message=message.line_print))
message.timeouted = True
if message.observe is not None:
self._observeLayer.remove_subscriber(message)
try:
self.to_be_stopped.remove(transaction.retransmit_stop)
except ValueError:
pass
transaction.retransmit_stop = None
transaction.retransmit_thread = None
def _start_separate_timer(self, transaction):
"""
Start a thread to handle separate mode.
:type transaction: Transaction
:param transaction: the transaction that is in processing
:rtype : the Timer object
"""
t = threading.Timer(defines.ACK_TIMEOUT, self._send_ack, (transaction,))
t.start()
return t
@staticmethod
def _stop_separate_timer(timer):
"""
Stop the separate Thread if an answer has been already provided to the client.
:param timer: The Timer object
"""
timer.cancel()
def _send_ack(self, transaction):
"""
Sends an ACK message for the request.
:param transaction: the transaction that owns the request
"""
ack = Message()
ack.type = defines.Types['ACK']
if not transaction.request.acknowledged:
ack = self._messageLayer.send_empty(transaction, transaction.request, ack)
self.send_datagram(ack)