First version of a realistic port generator

code/ID2TLib/Ports.py

@@ -0,0 +1,123 @@
+import random
+
+# information taken from https://www.cymru.com/jtk/misc/ephemeralports.html
+class PortRanges:
+	# dynamic ports as listed by RFC 6056
+	DYNAMIC_PORTS = range(49152, 65536)
+	
+	LINUX = range(32768, 61001)
+	FREEBSD = range(10000, 65536)
+	
+	APPLE_IOS = DYNAMIC_PORTS
+	APPLE_OSX = DYNAMIC_PORTS
+	
+	WINDOWS_7 = DYNAMIC_PORTS
+	WINDOWS_8 = DYNAMIC_PORTS
+	WINDOWS_VISTA = DYNAMIC_PORTS
+	WINDOWS_XP = range(1024, 5001)
+
+class PortSelectionStrategy:
+	@staticmethod
+	def sequential():
+		counter = -1
+		
+		# that function will always return a one higher counter than before,
+		# restarting from the start once it reached the highest value
+		def select_port(port_range):
+			global counter
+			if counter == -1:
+				counter = port_range.start
+			
+			port = counter
+			
+			counter += 1
+			if counter == port_range.stop:
+				counter = port_range.start
+			
+			return port
+		
+		return select_port
+	
+	@staticmethod
+	def random(port_range):
+		return random.randrange(port_range.start, port_range.stop)
+
+class PortSelector:
+	def __init__(self, port_range, select_function):
+		self.port_range = port_range
+		
+		self._select_port = select_function
+		
+		self.generated = []
+	
+	def select_port(self):
+		if len(self.generated) == len(self.port_range):
+			raise RuntimeError("All %i port numbers were already generated, no more can be generated" % len(self.port_range))
+		
+		while True:
+			port = self._select_port(self.port_range)
+			
+			if port not in self.generated:
+				self.generated.append(port)
+				return port
+	
+	def is_port_in_use(self, port):
+		return port in self.generated
+	
+	def undo_port_use(self, port):
+		if port in self.generated:
+			self.generated.remove(port)
+		else:
+			raise ValueError("Port %i is not in use and thus can not be undone" % port)
+	
+	def reduce_size(self, size):
+		self.generated = self.generated[-size:]
+	
+	def clear(self):
+		self.generated = []
+
+class ProtocolPortSelector:
+	def __init__(self, port_range, select_tcp, select_udp = None):
+		self.tcp = PortSelector(port_range, select_tcp)
+		self.udp = PortSelector(port_range, select_udp or select_tcp)
+	
+	def get_tcp_generator(self):
+		return self.tcp
+	
+	def get_udp_generator(self):
+		return self.udp
+	
+	def select_port_tcp(self):
+		return self.tcp.select_port()
+	
+	def select_port_udp(self):
+		return self.udp.select_port()
+	
+	def is_port_in_use_tcp(self, port):
+		return self.tcp.is_port_in_use(port)
+	
+	def is_port_in_use_udp(self, port):
+		return self.udp.is_port_in_use(port)
+	
+	def __getattr__(self, attr):
+		val = getattr(self.tcp, attr)
+		
+		if callable(val):
+			tcp_meth = val
+			udp_meth = getattr(self.udp, attr)
+			
+			def double_method(*args, **kwargs):
+				return (tcp_meth(*args, **kwargs), udp_meth(*args, **kwargs))
+			
+			return double_method
+		else:
+			return (val, getattr(self.udp, attr))
+
+class PortSelectors:
+	LINUX = ProtocolPortSelector(PortRanges.LINUX, PortSelectionStrategy.random)
+	APPLE = ProtocolPortSelector(PortRanges.DYNAMIC_PORTS,
+			PortSelectionStrategy.sequential(),
+			PortSelectionStrategy.random())
+	FREEBSD = ProtocolPortSelector(PortRanges.FREEBSD, PortSelectionStrategy.random)
+	WINDOWS = ProtocolPortSelector(PortRanges.WINDOWS_7, PortSelectionStrategy.random) # the selection strategy is a guess as i can't find more info on it
+