# -*- test-case-name: twisted.test.test_udp -*- # Copyright (c) Twisted Matrix Laboratories. # See LICENSE for details. """ Various asynchronous UDP classes. Please do not use this module directly. @var _sockErrReadIgnore: list of symbolic error constants (from the C{errno} module) representing socket errors where the error is temporary and can be ignored. @var _sockErrReadRefuse: list of symbolic error constants (from the C{errno} module) representing socket errors that indicate connection refused. """ from __future__ import division, absolute_import # System Imports import socket import operator import struct import warnings from zope.interface import implementer from twisted.python.runtime import platformType if platformType == 'win32': from errno import WSAEWOULDBLOCK from errno import WSAEINTR, WSAEMSGSIZE, WSAETIMEDOUT from errno import WSAECONNREFUSED, WSAECONNRESET, WSAENETRESET from errno import WSAEINPROGRESS # Classify read and write errors _sockErrReadIgnore = [WSAEINTR, WSAEWOULDBLOCK, WSAEMSGSIZE, WSAEINPROGRESS] _sockErrReadRefuse = [WSAECONNREFUSED, WSAECONNRESET, WSAENETRESET, WSAETIMEDOUT] # POSIX-compatible write errors EMSGSIZE = WSAEMSGSIZE ECONNREFUSED = WSAECONNREFUSED EAGAIN = WSAEWOULDBLOCK EINTR = WSAEINTR else: from errno import EWOULDBLOCK, EINTR, EMSGSIZE, ECONNREFUSED, EAGAIN _sockErrReadIgnore = [EAGAIN, EINTR, EWOULDBLOCK] _sockErrReadRefuse = [ECONNREFUSED] # Twisted Imports from twisted.internet import base, defer, address from twisted.python import log, failure from twisted.internet import abstract, error, interfaces @implementer( interfaces.IListeningPort, interfaces.IUDPTransport, interfaces.ISystemHandle) class Port(base.BasePort): """ UDP port, listening for packets. @ivar maxThroughput: Maximum number of bytes read in one event loop iteration. @ivar addressFamily: L{socket.AF_INET} or L{socket.AF_INET6}, depending on whether this port is listening on an IPv4 address or an IPv6 address. @ivar _realPortNumber: Actual port number being listened on. The value will be C{None} until this L{Port} is listening. @ivar _preexistingSocket: If not C{None}, a L{socket.socket} instance which was created and initialized outside of the reactor and will be used to listen for connections (instead of a new socket being created by this L{Port}). """ addressFamily = socket.AF_INET socketType = socket.SOCK_DGRAM maxThroughput = 256 * 1024 _realPortNumber = None _preexistingSocket = None def __init__(self, port, proto, interface='', maxPacketSize=8192, reactor=None): """ @param port: A port number on which to listen. @type port: C{int} @param proto: A C{DatagramProtocol} instance which will be connected to the given C{port}. @type proto: L{twisted.internet.protocol.DatagramProtocol} @param interface: The local IPv4 or IPv6 address to which to bind; defaults to '', ie all IPv4 addresses. @type interface: C{str} @param maxPacketSize: The maximum packet size to accept. @type maxPacketSize: C{int} @param reactor: A reactor which will notify this C{Port} when its socket is ready for reading or writing. Defaults to C{None}, ie the default global reactor. @type reactor: L{interfaces.IReactorFDSet} """ base.BasePort.__init__(self, reactor) self.port = port self.protocol = proto self.maxPacketSize = maxPacketSize self.interface = interface self.setLogStr() self._connectedAddr = None self._setAddressFamily() @classmethod def _fromListeningDescriptor(cls, reactor, fd, addressFamily, protocol, maxPacketSize): """ Create a new L{Port} based on an existing listening I{SOCK_DGRAM} socket. @param reactor: A reactor which will notify this L{Port} when its socket is ready for reading or writing. Defaults to C{None}, ie the default global reactor. @type reactor: L{interfaces.IReactorFDSet} @param fd: An integer file descriptor associated with a listening socket. The socket must be in non-blocking mode. Any additional attributes desired, such as I{FD_CLOEXEC}, must also be set already. @type fd: C{int} @param addressFamily: The address family (sometimes called I{domain}) of the existing socket. For example, L{socket.AF_INET}. @param addressFamily: C{int} @param protocol: A C{DatagramProtocol} instance which will be connected to the C{port}. @type proto: L{twisted.internet.protocol.DatagramProtocol} @param maxPacketSize: The maximum packet size to accept. @type maxPacketSize: C{int} @return: A new instance of C{cls} wrapping the socket given by C{fd}. @rtype: L{Port} """ port = socket.fromfd(fd, addressFamily, cls.socketType) interface = port.getsockname()[0] self = cls(None, protocol, interface=interface, reactor=reactor, maxPacketSize=maxPacketSize) self._preexistingSocket = port return self def __repr__(self): if self._realPortNumber is not None: return "<%s on %s>" % (self.protocol.__class__, self._realPortNumber) else: return "<%s not connected>" % (self.protocol.__class__,) def getHandle(self): """ Return a socket object. """ return self.socket def startListening(self): """ Create and bind my socket, and begin listening on it. This is called on unserialization, and must be called after creating a server to begin listening on the specified port. """ self._bindSocket() self._connectToProtocol() def _bindSocket(self): """ Prepare and assign a L{socket.socket} instance to C{self.socket}. Either creates a new SOCK_DGRAM L{socket.socket} bound to C{self.interface} and C{self.port} or takes an existing L{socket.socket} provided via the L{interfaces.IReactorSocket.adoptDatagramPort} interface. """ if self._preexistingSocket is None: # Create a new socket and make it listen try: skt = self.createInternetSocket() skt.bind((self.interface, self.port)) except socket.error as le: raise error.CannotListenError(self.interface, self.port, le) else: # Re-use the externally specified socket skt = self._preexistingSocket self._preexistingSocket = None # Make sure that if we listened on port 0, we update that to # reflect what the OS actually assigned us. self._realPortNumber = skt.getsockname()[1] log.msg("%s starting on %s" % ( self._getLogPrefix(self.protocol), self._realPortNumber)) self.connected = 1 self.socket = skt self.fileno = self.socket.fileno def _connectToProtocol(self): self.protocol.makeConnection(self) self.startReading() def doRead(self): """ Called when my socket is ready for reading. """ read = 0 while read < self.maxThroughput: try: data, addr = self.socket.recvfrom(self.maxPacketSize) except socket.error as se: no = se.args[0] if no in _sockErrReadIgnore: return if no in _sockErrReadRefuse: if self._connectedAddr: self.protocol.connectionRefused() return raise else: read += len(data) if self.addressFamily == socket.AF_INET6: # Remove the flow and scope ID from the address tuple, # reducing it to a tuple of just (host, port). # # TODO: This should be amended to return an object that can # unpack to (host, port) but also includes the flow info # and scope ID. See http://tm.tl/6826 addr = addr[:2] try: self.protocol.datagramReceived(data, addr) except: log.err() def write(self, datagram, addr=None): """ Write a datagram. @type datagram: C{str} @param datagram: The datagram to be sent. @type addr: C{tuple} containing C{str} as first element and C{int} as second element, or C{None} @param addr: A tuple of (I{stringified IPv4 or IPv6 address}, I{integer port number}); can be C{None} in connected mode. """ if self._connectedAddr: assert addr in (None, self._connectedAddr) try: return self.socket.send(datagram) except socket.error as se: no = se.args[0] if no == EINTR: return self.write(datagram) elif no == EMSGSIZE: raise error.MessageLengthError("message too long") elif no == ECONNREFUSED: self.protocol.connectionRefused() else: raise else: assert addr != None if (not abstract.isIPAddress(addr[0]) and not abstract.isIPv6Address(addr[0]) and addr[0] != ""): raise error.InvalidAddressError( addr[0], "write() only accepts IP addresses, not hostnames") if ((abstract.isIPAddress(addr[0]) or addr[0] == "") and self.addressFamily == socket.AF_INET6): raise error.InvalidAddressError( addr[0], "IPv6 port write() called with IPv4 or broadcast address") if (abstract.isIPv6Address(addr[0]) and self.addressFamily == socket.AF_INET): raise error.InvalidAddressError( addr[0], "IPv4 port write() called with IPv6 address") try: return self.socket.sendto(datagram, addr) except socket.error as se: no = se.args[0] if no == EINTR: return self.write(datagram, addr) elif no == EMSGSIZE: raise error.MessageLengthError("message too long") elif no == ECONNREFUSED: # in non-connected UDP ECONNREFUSED is platform dependent, I # think and the info is not necessarily useful. Nevertheless # maybe we should call connectionRefused? XXX return else: raise def writeSequence(self, seq, addr): self.write("".join(seq), addr) def connect(self, host, port): """ 'Connect' to remote server. """ if self._connectedAddr: raise RuntimeError("already connected, reconnecting is not currently supported") if not abstract.isIPAddress(host) and not abstract.isIPv6Address(host): raise error.InvalidAddressError( host, 'not an IPv4 or IPv6 address.') self._connectedAddr = (host, port) self.socket.connect((host, port)) def _loseConnection(self): self.stopReading() if self.connected: # actually means if we are *listening* self.reactor.callLater(0, self.connectionLost) def stopListening(self): if self.connected: result = self.d = defer.Deferred() else: result = None self._loseConnection() return result def loseConnection(self): warnings.warn("Please use stopListening() to disconnect port", DeprecationWarning, stacklevel=2) self.stopListening() def connectionLost(self, reason=None): """ Cleans up my socket. """ log.msg('(UDP Port %s Closed)' % self._realPortNumber) self._realPortNumber = None base.BasePort.connectionLost(self, reason) self.protocol.doStop() self.socket.close() del self.socket del self.fileno if hasattr(self, "d"): self.d.callback(None) del self.d def setLogStr(self): """ Initialize the C{logstr} attribute to be used by C{logPrefix}. """ logPrefix = self._getLogPrefix(self.protocol) self.logstr = "%s (UDP)" % logPrefix def _setAddressFamily(self): """ Resolve address family for the socket. """ if abstract.isIPv6Address(self.interface): self.addressFamily = socket.AF_INET6 elif abstract.isIPAddress(self.interface): self.addressFamily = socket.AF_INET elif self.interface: raise error.InvalidAddressError( self.interface, 'not an IPv4 or IPv6 address.') def logPrefix(self): """ Return the prefix to log with. """ return self.logstr def getHost(self): """ Return the local address of the UDP connection @returns: the local address of the UDP connection @rtype: L{IPv4Address} or L{IPv6Address} """ addr = self.socket.getsockname() if self.addressFamily == socket.AF_INET: return address.IPv4Address('UDP', *addr) elif self.addressFamily == socket.AF_INET6: return address.IPv6Address('UDP', *(addr[:2])) def setBroadcastAllowed(self, enabled): """ Set whether this port may broadcast. This is disabled by default. @param enabled: Whether the port may broadcast. @type enabled: L{bool} """ self.socket.setsockopt( socket.SOL_SOCKET, socket.SO_BROADCAST, enabled) def getBroadcastAllowed(self): """ Checks if broadcast is currently allowed on this port. @return: Whether this port may broadcast. @rtype: L{bool} """ return operator.truth( self.socket.getsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST)) class MulticastMixin: """ Implement multicast functionality. """ def getOutgoingInterface(self): i = self.socket.getsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_IF) return socket.inet_ntoa(struct.pack("@i", i)) def setOutgoingInterface(self, addr): """Returns Deferred of success.""" return self.reactor.resolve(addr).addCallback(self._setInterface) def _setInterface(self, addr): i = socket.inet_aton(addr) self.socket.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_IF, i) return 1 def getLoopbackMode(self): return self.socket.getsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_LOOP) def setLoopbackMode(self, mode): mode = struct.pack("b", operator.truth(mode)) self.socket.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_LOOP, mode) def getTTL(self): return self.socket.getsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL) def setTTL(self, ttl): ttl = struct.pack("B", ttl) self.socket.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, ttl) def joinGroup(self, addr, interface=""): """Join a multicast group. Returns Deferred of success.""" return self.reactor.resolve(addr).addCallback(self._joinAddr1, interface, 1) def _joinAddr1(self, addr, interface, join): return self.reactor.resolve(interface).addCallback(self._joinAddr2, addr, join) def _joinAddr2(self, interface, addr, join): addr = socket.inet_aton(addr) interface = socket.inet_aton(interface) if join: cmd = socket.IP_ADD_MEMBERSHIP else: cmd = socket.IP_DROP_MEMBERSHIP try: self.socket.setsockopt(socket.IPPROTO_IP, cmd, addr + interface) except socket.error as e: return failure.Failure(error.MulticastJoinError(addr, interface, *e.args)) def leaveGroup(self, addr, interface=""): """Leave multicast group, return Deferred of success.""" return self.reactor.resolve(addr).addCallback(self._joinAddr1, interface, 0) @implementer(interfaces.IMulticastTransport) class MulticastPort(MulticastMixin, Port): """ UDP Port that supports multicasting. """ def __init__(self, port, proto, interface='', maxPacketSize=8192, reactor=None, listenMultiple=False): """ @see: L{twisted.internet.interfaces.IReactorMulticast.listenMulticast} """ Port.__init__(self, port, proto, interface, maxPacketSize, reactor) self.listenMultiple = listenMultiple def createInternetSocket(self): skt = Port.createInternetSocket(self) if self.listenMultiple: skt.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) if hasattr(socket, "SO_REUSEPORT"): skt.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT, 1) return skt