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# -*- 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.
"""
# System Imports
import socket
import struct
import warnings
from typing import Optional
from zope.interface import implementer
from twisted.python.runtime import platformType
if platformType == "win32":
from errno import WSAEINPROGRESS # type: ignore[attr-defined]
from errno import WSAEWOULDBLOCK # type: ignore[attr-defined]
from errno import ( # type: ignore[attr-defined]
WSAECONNREFUSED,
WSAECONNRESET,
WSAEINTR,
WSAEMSGSIZE,
WSAENETRESET,
WSAENOPROTOOPT as ENOPROTOOPT,
WSAETIMEDOUT,
)
# 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 EAGAIN, ECONNREFUSED, EINTR, EMSGSIZE, ENOPROTOOPT, EWOULDBLOCK
_sockErrReadIgnore = [EAGAIN, EINTR, EWOULDBLOCK]
_sockErrReadRefuse = [ECONNREFUSED]
# Twisted Imports
from twisted.internet import abstract, address, base, defer, error, interfaces
from twisted.python import failure, log
@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 L{None} until this L{Port} is listening.
@ivar _preexistingSocket: If not L{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: Optional[int] = None
_preexistingSocket = None
def __init__(self, port, proto, interface="", maxPacketSize=8192, reactor=None):
"""
@param port: A port number on which to listen.
@type port: L{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: L{str}
@param maxPacketSize: The maximum packet size to accept.
@type maxPacketSize: L{int}
@param reactor: A reactor which will notify this C{Port} when
its socket is ready for reading or writing. Defaults to
L{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
L{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: L{int}
@param addressFamily: The address family (sometimes called I{domain}) of
the existing socket. For example, L{socket.AF_INET}.
@type addressFamily: L{int}
@param protocol: A C{DatagramProtocol} instance which will be
connected to the C{port}.
@type protocol: L{twisted.internet.protocol.DatagramProtocol}
@param maxPacketSize: The maximum packet size to accept.
@type maxPacketSize: L{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) -> str:
if self._realPortNumber is not None:
return f"<{self.protocol.__class__} on {self._realPortNumber}>"
else:
return f"<{self.protocol.__class__} not connected>"
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 OSError 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 OSError 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 BaseException:
log.err()
def write(self, datagram, addr=None):
"""
Write a datagram.
@type datagram: L{bytes}
@param datagram: The datagram to be sent.
@type addr: L{tuple} containing L{str} as first element and L{int} as
second element, or L{None}
@param addr: A tuple of (I{stringified IPv4 or IPv6 address},
I{integer port number}); can be L{None} in connected mode.
"""
if self._connectedAddr:
assert addr in (None, self._connectedAddr)
try:
return self.socket.send(datagram)
except OSError 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] != "<broadcast>"
):
raise error.InvalidAddressError(
addr[0], "write() only accepts IP addresses, not hostnames"
)
if (
abstract.isIPAddress(addr[0]) or addr[0] == "<broadcast>"
) 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 OSError 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):
"""
Write a datagram constructed from an iterable of L{bytes}.
@param seq: The data that will make up the complete datagram to be
written.
@type seq: an iterable of L{bytes}
@type addr: L{tuple} containing L{str} as first element and L{int} as
second element, or L{None}
@param addr: A tuple of (I{stringified IPv4 or IPv6 address},
I{integer port number}); can be L{None} in connected mode.
"""
self.write(b"".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
self.maxThroughput = -1
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 bool(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", bool(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 OSError 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"):
try:
skt.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT, 1)
except OSError as le:
# RHEL6 defines SO_REUSEPORT but it doesn't work
if le.errno == ENOPROTOOPT:
pass
else:
raise
return skt
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