77a50c7382
This change introduces a demux that uses the kernel's network stack for UDP datagram-to-socket assignment based on packet source address (as opposed to the forwarding strategy of the routing demux). The osnet demux is used by default on non-Windows platforms. When possible, use of the osnet demux is preferred over the routing demux, since it can be expected to perform better. The unit test suite has been extended to run all tests first with the demux selected by default for the current platform, and then with the routing demux, if the latter differs from the former. Tests were already being run twice, first with IPv4 and then with IPv6, and thus we now run each test four times on Linux, twice on Windows. All unit tests pass with both demux types.
105 lines
3.4 KiB
Python
105 lines
3.4 KiB
Python
# OSNet demux: uses the OS network stack to demultiplex incoming datagrams
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# among sockets bound to the same ports. Written by Ray Brown.
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"""OS Network UDP Demux
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This module implements a demux that uses the OS network stack to demultiplex
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datagrams coming from different peers among datagram sockets that are all bound
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to the port at which these datagrams are being received. The network stack is
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instructed as to which socket an incoming datagram should be sent to by
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connecting the destination socket to the peer endpoint.
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The OSNet demux requires operating system functionality that exists in the
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Linux kernel, but not in the Windows network stack.
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Classes:
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UDPDemux -- a network stack configuring UDP demux
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Exceptions:
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InvalidSocketError -- exception raised for improper socket objects
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KeyError -- raised for unknown peer addresses
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"""
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import socket
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from logging import getLogger
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from ..err import InvalidSocketError
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_logger = getLogger(__name__)
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class UDPDemux(object):
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"""OS network stack configuring demux
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This class implements a demux that creates sockets connected to peer
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network endpoints, configuring the network stack to demultiplex
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incoming datagrams from these endpoints among these sockets.
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Methods:
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get_connection -- create a new connection or retrieve an existing one
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service -- this method does nothing for this type of demux
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"""
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def __init__(self, datagram_socket):
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"""Constructor
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Arguments:
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datagram_socket -- the root socket; this must be a bound, unconnected
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datagram socket
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"""
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if datagram_socket.type != socket.SOCK_DGRAM:
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raise InvalidSocketError("datagram_socket is not of " +
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"type SOCK_DGRAM")
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try:
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datagram_socket.getsockname()
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except:
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raise InvalidSocketError("datagram_socket is unbound")
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try:
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datagram_socket.getpeername()
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except:
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pass
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else:
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raise InvalidSocketError("datagram_socket is connected")
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datagram_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
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self._datagram_socket = datagram_socket
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def get_connection(self, address):
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"""Create or retrieve a muxed connection
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Arguments:
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address -- a peer endpoint in IPv4/v6 address format; None refers
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to the connection for unknown peers
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Return:
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a bound, connected datagram socket instance, or the root socket
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in case address was None
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"""
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if not address:
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return self._datagram_socket
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# Create a new datagram socket bound to the same interface and port as
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# the root socket, but connected to the given peer
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conn = socket.socket(self._datagram_socket.family,
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self._datagram_socket.type,
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self._datagram_socket.proto)
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conn.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
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conn.bind(self._datagram_socket.getsockname())
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conn.connect(address)
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_logger.debug("Created new connection for address: %s", address)
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return conn
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@staticmethod
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def service():
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"""Service the root socket
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This type of demux performs no servicing work on the root socket,
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and instead advises the caller to proceed to listening on the root
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socket.
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"""
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return True
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