RAHHH

backend/lib/python3.12/site-packages/twisted/protocols/__init__.py

@@ -0,0 +1,6 @@
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""
+Twisted Protocols: A collection of internet protocol implementations.
+"""

backend/lib/python3.12/site-packages/twisted/protocols/basic.py

@@ -0,0 +1,912 @@
+# -*- test-case-name: twisted.protocols.test.test_basic -*-
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+
+"""
+Basic protocols, such as line-oriented, netstring, and int prefixed strings.
+"""
+
+
+import math
+
+# System imports
+import re
+from io import BytesIO
+from struct import calcsize, pack, unpack
+
+from zope.interface import implementer
+
+# Twisted imports
+from twisted.internet import defer, interfaces, protocol
+from twisted.python import log
+
+
+# Unfortunately we cannot use regular string formatting on Python 3; see
+# http://bugs.python.org/issue3982 for details.
+def _formatNetstring(data):
+    return b"".join([str(len(data)).encode("ascii"), b":", data, b","])
+
+
+_formatNetstring.__doc__ = """
+Convert some C{bytes} into netstring format.
+
+@param data: C{bytes} that will be reformatted.
+"""
+
+
+DEBUG = 0
+
+
+class NetstringParseError(ValueError):
+    """
+    The incoming data is not in valid Netstring format.
+    """
+
+
+class IncompleteNetstring(Exception):
+    """
+    Not enough data to complete a netstring.
+    """
+
+
+class NetstringReceiver(protocol.Protocol):
+    """
+    A protocol that sends and receives netstrings.
+
+    See U{http://cr.yp.to/proto/netstrings.txt} for the specification of
+    netstrings. Every netstring starts with digits that specify the length
+    of the data. This length specification is separated from the data by
+    a colon. The data is terminated with a comma.
+
+    Override L{stringReceived} to handle received netstrings. This
+    method is called with the netstring payload as a single argument
+    whenever a complete netstring is received.
+
+    Security features:
+        1. Messages are limited in size, useful if you don't want
+           someone sending you a 500MB netstring (change C{self.MAX_LENGTH}
+           to the maximum length you wish to accept).
+        2. The connection is lost if an illegal message is received.
+
+    @ivar MAX_LENGTH: Defines the maximum length of netstrings that can be
+        received.
+    @type MAX_LENGTH: C{int}
+
+    @ivar _LENGTH: A pattern describing all strings that contain a netstring
+        length specification. Examples for length specifications are C{b'0:'},
+        C{b'12:'}, and C{b'179:'}. C{b'007:'} is not a valid length
+        specification, since leading zeros are not allowed.
+    @type _LENGTH: C{re.Match}
+
+    @ivar _LENGTH_PREFIX: A pattern describing all strings that contain
+        the first part of a netstring length specification (without the
+        trailing comma). Examples are '0', '12', and '179'. '007' does not
+        start a netstring length specification, since leading zeros are
+        not allowed.
+    @type _LENGTH_PREFIX: C{re.Match}
+
+    @ivar _PARSING_LENGTH: Indicates that the C{NetstringReceiver} is in
+        the state of parsing the length portion of a netstring.
+    @type _PARSING_LENGTH: C{int}
+
+    @ivar _PARSING_PAYLOAD: Indicates that the C{NetstringReceiver} is in
+        the state of parsing the payload portion (data and trailing comma)
+        of a netstring.
+    @type _PARSING_PAYLOAD: C{int}
+
+    @ivar brokenPeer: Indicates if the connection is still functional
+    @type brokenPeer: C{int}
+
+    @ivar _state: Indicates if the protocol is consuming the length portion
+        (C{PARSING_LENGTH}) or the payload (C{PARSING_PAYLOAD}) of a netstring
+    @type _state: C{int}
+
+    @ivar _remainingData: Holds the chunk of data that has not yet been consumed
+    @type _remainingData: C{string}
+
+    @ivar _payload: Holds the payload portion of a netstring including the
+        trailing comma
+    @type _payload: C{BytesIO}
+
+    @ivar _expectedPayloadSize: Holds the payload size plus one for the trailing
+        comma.
+    @type _expectedPayloadSize: C{int}
+    """
+
+    MAX_LENGTH = 99999
+    _LENGTH = re.compile(rb"(0|[1-9]\d*)(:)")
+
+    _LENGTH_PREFIX = re.compile(rb"(0|[1-9]\d*)$")
+
+    # Some error information for NetstringParseError instances.
+    _MISSING_LENGTH = (
+        "The received netstring does not start with a " "length specification."
+    )
+    _OVERFLOW = (
+        "The length specification of the received netstring "
+        "cannot be represented in Python - it causes an "
+        "OverflowError!"
+    )
+    _TOO_LONG = (
+        "The received netstring is longer than the maximum %s "
+        "specified by self.MAX_LENGTH"
+    )
+    _MISSING_COMMA = "The received netstring is not terminated by a comma."
+
+    # The following constants are used for determining if the NetstringReceiver
+    # is parsing the length portion of a netstring, or the payload.
+    _PARSING_LENGTH, _PARSING_PAYLOAD = range(2)
+
+    def makeConnection(self, transport):
+        """
+        Initializes the protocol.
+        """
+        protocol.Protocol.makeConnection(self, transport)
+        self._remainingData = b""
+        self._currentPayloadSize = 0
+        self._payload = BytesIO()
+        self._state = self._PARSING_LENGTH
+        self._expectedPayloadSize = 0
+        self.brokenPeer = 0
+
+    def sendString(self, string):
+        """
+        Sends a netstring.
+
+        Wraps up C{string} by adding length information and a
+        trailing comma; writes the result to the transport.
+
+        @param string: The string to send.  The necessary framing (length
+            prefix, etc) will be added.
+        @type string: C{bytes}
+        """
+        self.transport.write(_formatNetstring(string))
+
+    def dataReceived(self, data):
+        """
+        Receives some characters of a netstring.
+
+        Whenever a complete netstring is received, this method extracts
+        its payload and calls L{stringReceived} to process it.
+
+        @param data: A chunk of data representing a (possibly partial)
+            netstring
+        @type data: C{bytes}
+        """
+        self._remainingData += data
+        while self._remainingData:
+            try:
+                self._consumeData()
+            except IncompleteNetstring:
+                break
+            except NetstringParseError:
+                self._handleParseError()
+                break
+
+    def stringReceived(self, string):
+        """
+        Override this for notification when each complete string is received.
+
+        @param string: The complete string which was received with all
+            framing (length prefix, etc) removed.
+        @type string: C{bytes}
+
+        @raise NotImplementedError: because the method has to be implemented
+            by the child class.
+        """
+        raise NotImplementedError()
+
+    def _maxLengthSize(self):
+        """
+        Calculate and return the string size of C{self.MAX_LENGTH}.
+
+        @return: The size of the string representation for C{self.MAX_LENGTH}
+        @rtype: C{float}
+        """
+        return math.ceil(math.log10(self.MAX_LENGTH)) + 1
+
+    def _consumeData(self):
+        """
+        Consumes the content of C{self._remainingData}.
+
+        @raise IncompleteNetstring: if C{self._remainingData} does not
+            contain enough data to complete the current netstring.
+        @raise NetstringParseError: if the received data do not
+            form a valid netstring.
+        """
+        if self._state == self._PARSING_LENGTH:
+            self._consumeLength()
+            self._prepareForPayloadConsumption()
+        if self._state == self._PARSING_PAYLOAD:
+            self._consumePayload()
+
+    def _consumeLength(self):
+        """
+        Consumes the length portion of C{self._remainingData}.
+
+        @raise IncompleteNetstring: if C{self._remainingData} contains
+            a partial length specification (digits without trailing
+            comma).
+        @raise NetstringParseError: if the received data do not form a valid
+            netstring.
+        """
+        lengthMatch = self._LENGTH.match(self._remainingData)
+        if not lengthMatch:
+            self._checkPartialLengthSpecification()
+            raise IncompleteNetstring()
+        self._processLength(lengthMatch)
+
+    def _checkPartialLengthSpecification(self):
+        """
+        Makes sure that the received data represents a valid number.
+
+        Checks if C{self._remainingData} represents a number smaller or
+        equal to C{self.MAX_LENGTH}.
+
+        @raise NetstringParseError: if C{self._remainingData} is no
+            number or is too big (checked by L{_extractLength}).
+        """
+        partialLengthMatch = self._LENGTH_PREFIX.match(self._remainingData)
+        if not partialLengthMatch:
+            raise NetstringParseError(self._MISSING_LENGTH)
+        lengthSpecification = partialLengthMatch.group(1)
+        self._extractLength(lengthSpecification)
+
+    def _processLength(self, lengthMatch):
+        """
+        Processes the length definition of a netstring.
+
+        Extracts and stores in C{self._expectedPayloadSize} the number
+        representing the netstring size.  Removes the prefix
+        representing the length specification from
+        C{self._remainingData}.
+
+        @raise NetstringParseError: if the received netstring does not
+            start with a number or the number is bigger than
+            C{self.MAX_LENGTH}.
+        @param lengthMatch: A regular expression match object matching
+            a netstring length specification
+        @type lengthMatch: C{re.Match}
+        """
+        endOfNumber = lengthMatch.end(1)
+        startOfData = lengthMatch.end(2)
+        lengthString = self._remainingData[:endOfNumber]
+        # Expect payload plus trailing comma:
+        self._expectedPayloadSize = self._extractLength(lengthString) + 1
+        self._remainingData = self._remainingData[startOfData:]
+
+    def _extractLength(self, lengthAsString):
+        """
+        Attempts to extract the length information of a netstring.
+
+        @raise NetstringParseError: if the number is bigger than
+            C{self.MAX_LENGTH}.
+        @param lengthAsString: A chunk of data starting with a length
+            specification
+        @type lengthAsString: C{bytes}
+        @return: The length of the netstring
+        @rtype: C{int}
+        """
+        self._checkStringSize(lengthAsString)
+        length = int(lengthAsString)
+        if length > self.MAX_LENGTH:
+            raise NetstringParseError(self._TOO_LONG % (self.MAX_LENGTH,))
+        return length
+
+    def _checkStringSize(self, lengthAsString):
+        """
+        Checks the sanity of lengthAsString.
+
+        Checks if the size of the length specification exceeds the
+        size of the string representing self.MAX_LENGTH. If this is
+        not the case, the number represented by lengthAsString is
+        certainly bigger than self.MAX_LENGTH, and a
+        NetstringParseError can be raised.
+
+        This method should make sure that netstrings with extremely
+        long length specifications are refused before even attempting
+        to convert them to an integer (which might trigger a
+        MemoryError).
+        """
+        if len(lengthAsString) > self._maxLengthSize():
+            raise NetstringParseError(self._TOO_LONG % (self.MAX_LENGTH,))
+
+    def _prepareForPayloadConsumption(self):
+        """
+        Sets up variables necessary for consuming the payload of a netstring.
+        """
+        self._state = self._PARSING_PAYLOAD
+        self._currentPayloadSize = 0
+        self._payload.seek(0)
+        self._payload.truncate()
+
+    def _consumePayload(self):
+        """
+        Consumes the payload portion of C{self._remainingData}.
+
+        If the payload is complete, checks for the trailing comma and
+        processes the payload. If not, raises an L{IncompleteNetstring}
+        exception.
+
+        @raise IncompleteNetstring: if the payload received so far
+            contains fewer characters than expected.
+        @raise NetstringParseError: if the payload does not end with a
+        comma.
+        """
+        self._extractPayload()
+        if self._currentPayloadSize < self._expectedPayloadSize:
+            raise IncompleteNetstring()
+        self._checkForTrailingComma()
+        self._state = self._PARSING_LENGTH
+        self._processPayload()
+
+    def _extractPayload(self):
+        """
+        Extracts payload information from C{self._remainingData}.
+
+        Splits C{self._remainingData} at the end of the netstring.  The
+        first part becomes C{self._payload}, the second part is stored
+        in C{self._remainingData}.
+
+        If the netstring is not yet complete, the whole content of
+        C{self._remainingData} is moved to C{self._payload}.
+        """
+        if self._payloadComplete():
+            remainingPayloadSize = self._expectedPayloadSize - self._currentPayloadSize
+            self._payload.write(self._remainingData[:remainingPayloadSize])
+            self._remainingData = self._remainingData[remainingPayloadSize:]
+            self._currentPayloadSize = self._expectedPayloadSize
+        else:
+            self._payload.write(self._remainingData)
+            self._currentPayloadSize += len(self._remainingData)
+            self._remainingData = b""
+
+    def _payloadComplete(self):
+        """
+        Checks if enough data have been received to complete the netstring.
+
+        @return: C{True} iff the received data contain at least as many
+            characters as specified in the length section of the
+            netstring
+        @rtype: C{bool}
+        """
+        return (
+            len(self._remainingData) + self._currentPayloadSize
+            >= self._expectedPayloadSize
+        )
+
+    def _processPayload(self):
+        """
+        Processes the actual payload with L{stringReceived}.
+
+        Strips C{self._payload} of the trailing comma and calls
+        L{stringReceived} with the result.
+        """
+        self.stringReceived(self._payload.getvalue()[:-1])
+
+    def _checkForTrailingComma(self):
+        """
+        Checks if the netstring has a trailing comma at the expected position.
+
+        @raise NetstringParseError: if the last payload character is
+            anything but a comma.
+        """
+        if self._payload.getvalue()[-1:] != b",":
+            raise NetstringParseError(self._MISSING_COMMA)
+
+    def _handleParseError(self):
+        """
+        Terminates the connection and sets the flag C{self.brokenPeer}.
+        """
+        self.transport.loseConnection()
+        self.brokenPeer = 1
+
+
+class LineOnlyReceiver(protocol.Protocol):
+    """
+    A protocol that receives only lines.
+
+    This is purely a speed optimisation over LineReceiver, for the
+    cases that raw mode is known to be unnecessary.
+
+    @cvar delimiter: The line-ending delimiter to use. By default this is
+                     C{b'\\r\\n'}.
+    @cvar MAX_LENGTH: The maximum length of a line to allow (If a
+                      sent line is longer than this, the connection is dropped).
+                      Default is 16384.
+    """
+
+    _buffer = b""
+    delimiter = b"\r\n"
+    MAX_LENGTH = 16384
+
+    def dataReceived(self, data):
+        """
+        Translates bytes into lines, and calls lineReceived.
+        """
+        lines = (self._buffer + data).split(self.delimiter)
+        self._buffer = lines.pop(-1)
+        for line in lines:
+            if self.transport.disconnecting:
+                # this is necessary because the transport may be told to lose
+                # the connection by a line within a larger packet, and it is
+                # important to disregard all the lines in that packet following
+                # the one that told it to close.
+                return
+            if len(line) > self.MAX_LENGTH:
+                return self.lineLengthExceeded(line)
+            else:
+                self.lineReceived(line)
+        if len(self._buffer) > self.MAX_LENGTH:
+            return self.lineLengthExceeded(self._buffer)
+
+    def lineReceived(self, line):
+        """
+        Override this for when each line is received.
+
+        @param line: The line which was received with the delimiter removed.
+        @type line: C{bytes}
+        """
+        raise NotImplementedError
+
+    def sendLine(self, line):
+        """
+        Sends a line to the other end of the connection.
+
+        @param line: The line to send, not including the delimiter.
+        @type line: C{bytes}
+        """
+        return self.transport.writeSequence((line, self.delimiter))
+
+    def lineLengthExceeded(self, line):
+        """
+        Called when the maximum line length has been reached.
+        Override if it needs to be dealt with in some special way.
+        """
+        return self.transport.loseConnection()
+
+
+class _PauseableMixin:
+    paused = False
+
+    def pauseProducing(self):
+        self.paused = True
+        self.transport.pauseProducing()
+
+    def resumeProducing(self):
+        self.paused = False
+        self.transport.resumeProducing()
+        self.dataReceived(b"")
+
+    def stopProducing(self):
+        self.paused = True
+        self.transport.stopProducing()
+
+
+class LineReceiver(protocol.Protocol, _PauseableMixin):
+    """
+    A protocol that receives lines and/or raw data, depending on mode.
+
+    In line mode, each line that's received becomes a callback to
+    L{lineReceived}.  In raw data mode, each chunk of raw data becomes a
+    callback to L{LineReceiver.rawDataReceived}.
+    The L{setLineMode} and L{setRawMode} methods switch between the two modes.
+
+    This is useful for line-oriented protocols such as IRC, HTTP, POP, etc.
+
+    @cvar delimiter: The line-ending delimiter to use. By default this is
+                     C{b'\\r\\n'}.
+    @cvar MAX_LENGTH: The maximum length of a line to allow (If a
+                      sent line is longer than this, the connection is dropped).
+                      Default is 16384.
+    """
+
+    line_mode = 1
+    _buffer = b""
+    _busyReceiving = False
+    delimiter = b"\r\n"
+    MAX_LENGTH = 16384
+
+    def clearLineBuffer(self):
+        """
+        Clear buffered data.
+
+        @return: All of the cleared buffered data.
+        @rtype: C{bytes}
+        """
+        b, self._buffer = self._buffer, b""
+        return b
+
+    def dataReceived(self, data):
+        """
+        Protocol.dataReceived.
+        Translates bytes into lines, and calls lineReceived (or
+        rawDataReceived, depending on mode.)
+        """
+        if self._busyReceiving:
+            self._buffer += data
+            return
+
+        try:
+            self._busyReceiving = True
+            self._buffer += data
+            while self._buffer and not self.paused:
+                if self.line_mode:
+                    try:
+                        line, self._buffer = self._buffer.split(self.delimiter, 1)
+                    except ValueError:
+                        if len(self._buffer) >= (self.MAX_LENGTH + len(self.delimiter)):
+                            line, self._buffer = self._buffer, b""
+                            return self.lineLengthExceeded(line)
+                        return
+                    else:
+                        lineLength = len(line)
+                        if lineLength > self.MAX_LENGTH:
+                            exceeded = line + self.delimiter + self._buffer
+                            self._buffer = b""
+                            return self.lineLengthExceeded(exceeded)
+                        why = self.lineReceived(line)
+                        if why or self.transport and self.transport.disconnecting:
+                            return why
+                else:
+                    data = self._buffer
+                    self._buffer = b""
+                    why = self.rawDataReceived(data)
+                    if why:
+                        return why
+        finally:
+            self._busyReceiving = False
+
+    def setLineMode(self, extra=b""):
+        """
+        Sets the line-mode of this receiver.
+
+        If you are calling this from a rawDataReceived callback,
+        you can pass in extra unhandled data, and that data will
+        be parsed for lines.  Further data received will be sent
+        to lineReceived rather than rawDataReceived.
+
+        Do not pass extra data if calling this function from
+        within a lineReceived callback.
+        """
+        self.line_mode = 1
+        if extra:
+            return self.dataReceived(extra)
+
+    def setRawMode(self):
+        """
+        Sets the raw mode of this receiver.
+        Further data received will be sent to rawDataReceived rather
+        than lineReceived.
+        """
+        self.line_mode = 0
+
+    def rawDataReceived(self, data):
+        """
+        Override this for when raw data is received.
+        """
+        raise NotImplementedError
+
+    def lineReceived(self, line):
+        """
+        Override this for when each line is received.
+
+        @param line: The line which was received with the delimiter removed.
+        @type line: C{bytes}
+        """
+        raise NotImplementedError
+
+    def sendLine(self, line):
+        """
+        Sends a line to the other end of the connection.
+
+        @param line: The line to send, not including the delimiter.
+        @type line: C{bytes}
+        """
+        return self.transport.write(line + self.delimiter)
+
+    def lineLengthExceeded(self, line):
+        """
+        Called when the maximum line length has been reached.
+        Override if it needs to be dealt with in some special way.
+
+        The argument 'line' contains the remainder of the buffer, starting
+        with (at least some part) of the line which is too long. This may
+        be more than one line, or may be only the initial portion of the
+        line.
+        """
+        return self.transport.loseConnection()
+
+
+class StringTooLongError(AssertionError):
+    """
+    Raised when trying to send a string too long for a length prefixed
+    protocol.
+    """
+
+
+class _RecvdCompatHack:
+    """
+    Emulates the to-be-deprecated C{IntNStringReceiver.recvd} attribute.
+
+    The C{recvd} attribute was where the working buffer for buffering and
+    parsing netstrings was kept.  It was updated each time new data arrived and
+    each time some of that data was parsed and delivered to application code.
+    The piecemeal updates to its string value were expensive and have been
+    removed from C{IntNStringReceiver} in the normal case.  However, for
+    applications directly reading this attribute, this descriptor restores that
+    behavior.  It only copies the working buffer when necessary (ie, when
+    accessed).  This avoids the cost for applications not using the data.
+
+    This is a custom descriptor rather than a property, because we still need
+    the default __set__ behavior in both new-style and old-style subclasses.
+    """
+
+    def __get__(self, oself, type=None):
+        return oself._unprocessed[oself._compatibilityOffset :]
+
+
+class IntNStringReceiver(protocol.Protocol, _PauseableMixin):
+    """
+    Generic class for length prefixed protocols.
+
+    @ivar _unprocessed: bytes received, but not yet broken up into messages /
+        sent to stringReceived.  _compatibilityOffset must be updated when this
+        value is updated so that the C{recvd} attribute can be generated
+        correctly.
+    @type _unprocessed: C{bytes}
+
+    @ivar structFormat: format used for struct packing/unpacking. Define it in
+        subclass.
+    @type structFormat: C{str}
+
+    @ivar prefixLength: length of the prefix, in bytes. Define it in subclass,
+        using C{struct.calcsize(structFormat)}
+    @type prefixLength: C{int}
+
+    @ivar _compatibilityOffset: the offset within C{_unprocessed} to the next
+        message to be parsed. (used to generate the recvd attribute)
+    @type _compatibilityOffset: C{int}
+    """
+
+    MAX_LENGTH = 99999
+    _unprocessed = b""
+    _compatibilityOffset = 0
+
+    # Backwards compatibility support for applications which directly touch the
+    # "internal" parse buffer.
+    recvd = _RecvdCompatHack()
+
+    def stringReceived(self, string):
+        """
+        Override this for notification when each complete string is received.
+
+        @param string: The complete string which was received with all
+            framing (length prefix, etc) removed.
+        @type string: C{bytes}
+        """
+        raise NotImplementedError
+
+    def lengthLimitExceeded(self, length):
+        """
+        Callback invoked when a length prefix greater than C{MAX_LENGTH} is
+        received.  The default implementation disconnects the transport.
+        Override this.
+
+        @param length: The length prefix which was received.
+        @type length: C{int}
+        """
+        self.transport.loseConnection()
+
+    def dataReceived(self, data):
+        """
+        Convert int prefixed strings into calls to stringReceived.
+        """
+        # Try to minimize string copying (via slices) by keeping one buffer
+        # containing all the data we have so far and a separate offset into that
+        # buffer.
+        alldata = self._unprocessed + data
+        currentOffset = 0
+        prefixLength = self.prefixLength
+        fmt = self.structFormat
+        self._unprocessed = alldata
+
+        while len(alldata) >= (currentOffset + prefixLength) and not self.paused:
+            messageStart = currentOffset + prefixLength
+            (length,) = unpack(fmt, alldata[currentOffset:messageStart])
+            if length > self.MAX_LENGTH:
+                self._unprocessed = alldata
+                self._compatibilityOffset = currentOffset
+                self.lengthLimitExceeded(length)
+                return
+            messageEnd = messageStart + length
+            if len(alldata) < messageEnd:
+                break
+
+            # Here we have to slice the working buffer so we can send just the
+            # netstring into the stringReceived callback.
+            packet = alldata[messageStart:messageEnd]
+            currentOffset = messageEnd
+            self._compatibilityOffset = currentOffset
+            self.stringReceived(packet)
+
+            # Check to see if the backwards compat "recvd" attribute got written
+            # to by application code.  If so, drop the current data buffer and
+            # switch to the new buffer given by that attribute's value.
+            if "recvd" in self.__dict__:
+                alldata = self.__dict__.pop("recvd")
+                self._unprocessed = alldata
+                self._compatibilityOffset = currentOffset = 0
+                if alldata:
+                    continue
+                return
+
+        # Slice off all the data that has been processed, avoiding holding onto
+        # memory to store it, and update the compatibility attributes to reflect
+        # that change.
+        self._unprocessed = alldata[currentOffset:]
+        self._compatibilityOffset = 0
+
+    def sendString(self, string):
+        """
+        Send a prefixed string to the other end of the connection.
+
+        @param string: The string to send.  The necessary framing (length
+            prefix, etc) will be added.
+        @type string: C{bytes}
+        """
+        if len(string) >= 2 ** (8 * self.prefixLength):
+            raise StringTooLongError(
+                "Try to send %s bytes whereas maximum is %s"
+                % (len(string), 2 ** (8 * self.prefixLength))
+            )
+        self.transport.write(pack(self.structFormat, len(string)) + string)
+
+
+class Int32StringReceiver(IntNStringReceiver):
+    """
+    A receiver for int32-prefixed strings.
+
+    An int32 string is a string prefixed by 4 bytes, the 32-bit length of
+    the string encoded in network byte order.
+
+    This class publishes the same interface as NetstringReceiver.
+    """
+
+    structFormat = "!I"
+    prefixLength = calcsize(structFormat)
+
+
+class Int16StringReceiver(IntNStringReceiver):
+    """
+    A receiver for int16-prefixed strings.
+
+    An int16 string is a string prefixed by 2 bytes, the 16-bit length of
+    the string encoded in network byte order.
+
+    This class publishes the same interface as NetstringReceiver.
+    """
+
+    structFormat = "!H"
+    prefixLength = calcsize(structFormat)
+
+
+class Int8StringReceiver(IntNStringReceiver):
+    """
+    A receiver for int8-prefixed strings.
+
+    An int8 string is a string prefixed by 1 byte, the 8-bit length of
+    the string.
+
+    This class publishes the same interface as NetstringReceiver.
+    """
+
+    structFormat = "!B"
+    prefixLength = calcsize(structFormat)
+
+
+class StatefulStringProtocol:
+    """
+    A stateful string protocol.
+
+    This is a mixin for string protocols (L{Int32StringReceiver},
+    L{NetstringReceiver}) which translates L{stringReceived} into a callback
+    (prefixed with C{'proto_'}) depending on state.
+
+    The state C{'done'} is special; if a C{proto_*} method returns it, the
+    connection will be closed immediately.
+
+    @ivar state: Current state of the protocol. Defaults to C{'init'}.
+    @type state: C{str}
+    """
+
+    state = "init"
+
+    def stringReceived(self, string):
+        """
+        Choose a protocol phase function and call it.
+
+        Call back to the appropriate protocol phase; this begins with
+        the function C{proto_init} and moves on to C{proto_*} depending on
+        what each C{proto_*} function returns.  (For example, if
+        C{self.proto_init} returns 'foo', then C{self.proto_foo} will be the
+        next function called when a protocol message is received.
+        """
+        try:
+            pto = "proto_" + self.state
+            statehandler = getattr(self, pto)
+        except AttributeError:
+            log.msg("callback", self.state, "not found")
+        else:
+            self.state = statehandler(string)
+            if self.state == "done":
+                self.transport.loseConnection()
+
+
+@implementer(interfaces.IProducer)
+class FileSender:
+    """
+    A producer that sends the contents of a file to a consumer.
+
+    This is a helper for protocols that, at some point, will take a
+    file-like object, read its contents, and write them out to the network,
+    optionally performing some transformation on the bytes in between.
+    """
+
+    CHUNK_SIZE = 2**14
+
+    lastSent = ""
+    deferred = None
+
+    def beginFileTransfer(self, file, consumer, transform=None):
+        """
+        Begin transferring a file
+
+        @type file: Any file-like object
+        @param file: The file object to read data from
+
+        @type consumer: Any implementor of IConsumer
+        @param consumer: The object to write data to
+
+        @param transform: A callable taking one string argument and returning
+        the same.  All bytes read from the file are passed through this before
+        being written to the consumer.
+
+        @rtype: C{Deferred}
+        @return: A deferred whose callback will be invoked when the file has
+        been completely written to the consumer. The last byte written to the
+        consumer is passed to the callback.
+        """
+        self.file = file
+        self.consumer = consumer
+        self.transform = transform
+
+        self.deferred = deferred = defer.Deferred()
+        self.consumer.registerProducer(self, False)
+        return deferred
+
+    def resumeProducing(self):
+        chunk = ""
+        if self.file:
+            chunk = self.file.read(self.CHUNK_SIZE)
+        if not chunk:
+            self.file = None
+            self.consumer.unregisterProducer()
+            if self.deferred:
+                self.deferred.callback(self.lastSent)
+                self.deferred = None
+            return
+
+        if self.transform:
+            chunk = self.transform(chunk)
+        self.consumer.write(chunk)
+        self.lastSent = chunk[-1:]
+
+    def pauseProducing(self):
+        pass
+
+    def stopProducing(self):
+        if self.deferred:
+            self.deferred.errback(Exception("Consumer asked us to stop producing"))
+            self.deferred = None

backend/lib/python3.12/site-packages/twisted/protocols/finger.py

@@ -0,0 +1,42 @@
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+
+"""The Finger User Information Protocol (RFC 1288)"""
+
+from twisted.protocols import basic
+
+
+class Finger(basic.LineReceiver):
+    def lineReceived(self, line):
+        parts = line.split()
+        if not parts:
+            parts = [b""]
+        if len(parts) == 1:
+            slash_w = 0
+        else:
+            slash_w = 1
+        user = parts[-1]
+        if b"@" in user:
+            hostPlace = user.rfind(b"@")
+            user = user[:hostPlace]
+            host = user[hostPlace + 1 :]
+            return self.forwardQuery(slash_w, user, host)
+        if user:
+            return self.getUser(slash_w, user)
+        else:
+            return self.getDomain(slash_w)
+
+    def _refuseMessage(self, message):
+        self.transport.write(message + b"\n")
+        self.transport.loseConnection()
+
+    def forwardQuery(self, slash_w, user, host):
+        self._refuseMessage(b"Finger forwarding service denied")
+
+    def getDomain(self, slash_w):
+        self._refuseMessage(b"Finger online list denied")
+
+    def getUser(self, slash_w, user):
+        self.transport.write(b"Login: " + user + b"\n")
+        self._refuseMessage(b"No such user")

backend/lib/python3.12/site-packages/twisted/protocols/haproxy/__init__.py

@@ -0,0 +1,10 @@
+# -*- test-case-name: twisted.protocols.haproxy.test -*-
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""
+HAProxy PROXY protocol implementations.
+"""
+__all__ = ["proxyEndpoint"]
+
+from ._wrapper import proxyEndpoint

backend/lib/python3.12/site-packages/twisted/protocols/haproxy/_exceptions.py

@@ -0,0 +1,49 @@
+# -*- test-case-name: twisted.protocols.haproxy.test -*-
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""
+HAProxy specific exceptions.
+"""
+
+import contextlib
+from typing import Callable, Generator, Type
+
+
+class InvalidProxyHeader(Exception):
+    """
+    The provided PROXY protocol header is invalid.
+    """
+
+
+class InvalidNetworkProtocol(InvalidProxyHeader):
+    """
+    The network protocol was not one of TCP4 TCP6 or UNKNOWN.
+    """
+
+
+class MissingAddressData(InvalidProxyHeader):
+    """
+    The address data is missing or incomplete.
+    """
+
+
+@contextlib.contextmanager
+def convertError(
+    sourceType: Type[BaseException], targetType: Callable[[], BaseException]
+) -> Generator[None, None, None]:
+    """
+    Convert an error into a different error type.
+
+    @param sourceType: The type of exception that should be caught and
+        converted.
+    @type sourceType: L{BaseException}
+
+    @param targetType: The type of exception to which the original should be
+        converted.
+    @type targetType: L{BaseException}
+    """
+    try:
+        yield
+    except sourceType as e:
+        raise targetType().with_traceback(e.__traceback__)

backend/lib/python3.12/site-packages/twisted/protocols/haproxy/_info.py

@@ -0,0 +1,34 @@
+# -*- test-case-name: twisted.protocols.haproxy.test -*-
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""
+IProxyInfo implementation.
+"""
+from typing import Optional
+
+from zope.interface import implementer
+
+import attr
+
+from twisted.internet.interfaces import IAddress
+from ._interfaces import IProxyInfo
+
+
+@implementer(IProxyInfo)
+@attr.s(frozen=True, slots=True, auto_attribs=True)
+class ProxyInfo:
+    """
+    A data container for parsed PROXY protocol information.
+
+    @ivar header: The raw header bytes extracted from the connection.
+    @type header: C{bytes}
+    @ivar source: The connection source address.
+    @type source: L{twisted.internet.interfaces.IAddress}
+    @ivar destination: The connection destination address.
+    @type destination: L{twisted.internet.interfaces.IAddress}
+    """
+
+    header: bytes
+    source: Optional[IAddress]
+    destination: Optional[IAddress]

backend/lib/python3.12/site-packages/twisted/protocols/haproxy/_interfaces.py

@@ -0,0 +1,63 @@
+# -*- test-case-name: twisted.protocols.haproxy.test -*-
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""
+Interfaces used by the PROXY protocol modules.
+"""
+from typing import Tuple, Union
+
+import zope.interface
+
+
+class IProxyInfo(zope.interface.Interface):
+    """
+    Data container for PROXY protocol header data.
+    """
+
+    header = zope.interface.Attribute(
+        "The raw byestring that represents the PROXY protocol header.",
+    )
+    source = zope.interface.Attribute(
+        "An L{twisted.internet.interfaces.IAddress} representing the "
+        "connection source."
+    )
+    destination = zope.interface.Attribute(
+        "An L{twisted.internet.interfaces.IAddress} representing the "
+        "connection destination."
+    )
+
+
+class IProxyParser(zope.interface.Interface):
+    """
+    Streaming parser that handles PROXY protocol headers.
+    """
+
+    def feed(data: bytes) -> Union[Tuple[IProxyInfo, bytes], Tuple[None, None]]:
+        """
+        Consume a chunk of data and attempt to parse it.
+
+        @param data: A bytestring.
+        @type data: bytes
+
+        @return: A two-tuple containing, in order, an L{IProxyInfo} and any
+            bytes fed to the parser that followed the end of the header.  Both
+            of these values are None until a complete header is parsed.
+
+        @raises InvalidProxyHeader: If the bytes fed to the parser create an
+            invalid PROXY header.
+        """
+
+    def parse(line: bytes) -> IProxyInfo:
+        """
+        Parse a bytestring as a full PROXY protocol header line.
+
+        @param line: A bytestring that represents a valid HAProxy PROXY
+            protocol header line.
+        @type line: bytes
+
+        @return: An L{IProxyInfo} containing the parsed data.
+
+        @raises InvalidProxyHeader: If the bytestring does not represent a
+            valid PROXY header.
+        """

backend/lib/python3.12/site-packages/twisted/protocols/haproxy/_parser.py

@@ -0,0 +1,75 @@
+# -*- test-case-name: twisted.protocols.haproxy.test.test_parser -*-
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""
+Parser for 'haproxy:' string endpoint.
+"""
+from typing import Mapping, Tuple
+
+from zope.interface import implementer
+
+from twisted.internet import interfaces
+from twisted.internet.endpoints import (
+    IStreamServerEndpointStringParser,
+    _WrapperServerEndpoint,
+    quoteStringArgument,
+    serverFromString,
+)
+from twisted.plugin import IPlugin
+from . import proxyEndpoint
+
+
+def unparseEndpoint(args: Tuple[object, ...], kwargs: Mapping[str, object]) -> str:
+    """
+    Un-parse the already-parsed args and kwargs back into endpoint syntax.
+
+    @param args: C{:}-separated arguments
+
+    @param kwargs: C{:} and then C{=}-separated keyword arguments
+
+    @return: a string equivalent to the original format which this was parsed
+        as.
+    """
+
+    description = ":".join(
+        [quoteStringArgument(str(arg)) for arg in args]
+        + sorted(
+            "{}={}".format(
+                quoteStringArgument(str(key)), quoteStringArgument(str(value))
+            )
+            for key, value in kwargs.items()
+        )
+    )
+    return description
+
+
+@implementer(IPlugin, IStreamServerEndpointStringParser)
+class HAProxyServerParser:
+    """
+    Stream server endpoint string parser for the HAProxyServerEndpoint type.
+
+    @ivar prefix: See L{IStreamServerEndpointStringParser.prefix}.
+    """
+
+    prefix = "haproxy"
+
+    def parseStreamServer(
+        self, reactor: interfaces.IReactorCore, *args: object, **kwargs: object
+    ) -> _WrapperServerEndpoint:
+        """
+        Parse a stream server endpoint from a reactor and string-only arguments
+        and keyword arguments.
+
+        @param reactor: The reactor.
+
+        @param args: The parsed string arguments.
+
+        @param kwargs: The parsed keyword arguments.
+
+        @return: a stream server endpoint
+        @rtype: L{IStreamServerEndpoint}
+        """
+        subdescription = unparseEndpoint(args, kwargs)
+        wrappedEndpoint = serverFromString(reactor, subdescription)
+        return proxyEndpoint(wrappedEndpoint)

backend/lib/python3.12/site-packages/twisted/protocols/haproxy/_v1parser.py

@@ -0,0 +1,142 @@
+# -*- test-case-name: twisted.protocols.haproxy.test.test_v1parser -*-
+
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""
+IProxyParser implementation for version one of the PROXY protocol.
+"""
+from typing import Tuple, Union
+
+from zope.interface import implementer
+
+from twisted.internet import address
+from . import _info, _interfaces
+from ._exceptions import (
+    InvalidNetworkProtocol,
+    InvalidProxyHeader,
+    MissingAddressData,
+    convertError,
+)
+
+
+@implementer(_interfaces.IProxyParser)
+class V1Parser:
+    """
+    PROXY protocol version one header parser.
+
+    Version one of the PROXY protocol is a human readable format represented
+    by a single, newline delimited binary string that contains all of the
+    relevant source and destination data.
+    """
+
+    PROXYSTR = b"PROXY"
+    UNKNOWN_PROTO = b"UNKNOWN"
+    TCP4_PROTO = b"TCP4"
+    TCP6_PROTO = b"TCP6"
+    ALLOWED_NET_PROTOS = (
+        TCP4_PROTO,
+        TCP6_PROTO,
+        UNKNOWN_PROTO,
+    )
+    NEWLINE = b"\r\n"
+
+    def __init__(self) -> None:
+        self.buffer = b""
+
+    def feed(
+        self, data: bytes
+    ) -> Union[Tuple[_info.ProxyInfo, bytes], Tuple[None, None]]:
+        """
+        Consume a chunk of data and attempt to parse it.
+
+        @param data: A bytestring.
+        @type data: L{bytes}
+
+        @return: A two-tuple containing, in order, a
+            L{_interfaces.IProxyInfo} and any bytes fed to the
+            parser that followed the end of the header.  Both of these values
+            are None until a complete header is parsed.
+
+        @raises InvalidProxyHeader: If the bytes fed to the parser create an
+            invalid PROXY header.
+        """
+        self.buffer += data
+        if len(self.buffer) > 107 and self.NEWLINE not in self.buffer:
+            raise InvalidProxyHeader()
+        lines = (self.buffer).split(self.NEWLINE, 1)
+        if not len(lines) > 1:
+            return (None, None)
+        self.buffer = b""
+        remaining = lines.pop()
+        header = lines.pop()
+        info = self.parse(header)
+        return (info, remaining)
+
+    @classmethod
+    def parse(cls, line: bytes) -> _info.ProxyInfo:
+        """
+        Parse a bytestring as a full PROXY protocol header line.
+
+        @param line: A bytestring that represents a valid HAProxy PROXY
+            protocol header line.
+        @type line: bytes
+
+        @return: A L{_interfaces.IProxyInfo} containing the parsed data.
+
+        @raises InvalidProxyHeader: If the bytestring does not represent a
+            valid PROXY header.
+
+        @raises InvalidNetworkProtocol: When no protocol can be parsed or is
+            not one of the allowed values.
+
+        @raises MissingAddressData: When the protocol is TCP* but the header
+            does not contain a complete set of addresses and ports.
+        """
+        originalLine = line
+        proxyStr = None
+        networkProtocol = None
+        sourceAddr = None
+        sourcePort = None
+        destAddr = None
+        destPort = None
+
+        with convertError(ValueError, InvalidProxyHeader):
+            proxyStr, line = line.split(b" ", 1)
+
+        if proxyStr != cls.PROXYSTR:
+            raise InvalidProxyHeader()
+
+        with convertError(ValueError, InvalidNetworkProtocol):
+            networkProtocol, line = line.split(b" ", 1)
+
+        if networkProtocol not in cls.ALLOWED_NET_PROTOS:
+            raise InvalidNetworkProtocol()
+
+        if networkProtocol == cls.UNKNOWN_PROTO:
+            return _info.ProxyInfo(originalLine, None, None)
+
+        with convertError(ValueError, MissingAddressData):
+            sourceAddr, line = line.split(b" ", 1)
+
+        with convertError(ValueError, MissingAddressData):
+            destAddr, line = line.split(b" ", 1)
+
+        with convertError(ValueError, MissingAddressData):
+            sourcePort, line = line.split(b" ", 1)
+
+        with convertError(ValueError, MissingAddressData):
+            destPort = line.split(b" ")[0]
+
+        if networkProtocol == cls.TCP4_PROTO:
+            return _info.ProxyInfo(
+                originalLine,
+                address.IPv4Address("TCP", sourceAddr.decode(), int(sourcePort)),
+                address.IPv4Address("TCP", destAddr.decode(), int(destPort)),
+            )
+
+        return _info.ProxyInfo(
+            originalLine,
+            address.IPv6Address("TCP", sourceAddr.decode(), int(sourcePort)),
+            address.IPv6Address("TCP", destAddr.decode(), int(destPort)),
+        )

backend/lib/python3.12/site-packages/twisted/protocols/haproxy/_v2parser.py

@@ -0,0 +1,217 @@
+# -*- test-case-name: twisted.protocols.haproxy.test.test_v2parser -*-
+
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""
+IProxyParser implementation for version two of the PROXY protocol.
+"""
+
+import binascii
+import struct
+from typing import Callable, Tuple, Type, Union
+
+from zope.interface import implementer
+
+from constantly import ValueConstant, Values
+from typing_extensions import Literal
+
+from twisted.internet import address
+from twisted.python import compat
+from . import _info, _interfaces
+from ._exceptions import (
+    InvalidNetworkProtocol,
+    InvalidProxyHeader,
+    MissingAddressData,
+    convertError,
+)
+
+
+class NetFamily(Values):
+    """
+    Values for the 'family' field.
+    """
+
+    UNSPEC = ValueConstant(0x00)
+    INET = ValueConstant(0x10)
+    INET6 = ValueConstant(0x20)
+    UNIX = ValueConstant(0x30)
+
+
+class NetProtocol(Values):
+    """
+    Values for 'protocol' field.
+    """
+
+    UNSPEC = ValueConstant(0)
+    STREAM = ValueConstant(1)
+    DGRAM = ValueConstant(2)
+
+
+_HIGH = 0b11110000
+_LOW = 0b00001111
+_LOCALCOMMAND = "LOCAL"
+_PROXYCOMMAND = "PROXY"
+
+
+@implementer(_interfaces.IProxyParser)
+class V2Parser:
+    """
+    PROXY protocol version two header parser.
+
+    Version two of the PROXY protocol is a binary format.
+    """
+
+    PREFIX = b"\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A"
+    VERSIONS = [32]
+    COMMANDS = {0: _LOCALCOMMAND, 1: _PROXYCOMMAND}
+    ADDRESSFORMATS = {
+        # TCP4
+        17: "!4s4s2H",
+        18: "!4s4s2H",
+        # TCP6
+        33: "!16s16s2H",
+        34: "!16s16s2H",
+        # UNIX
+        49: "!108s108s",
+        50: "!108s108s",
+    }
+
+    def __init__(self) -> None:
+        self.buffer = b""
+
+    def feed(
+        self, data: bytes
+    ) -> Union[Tuple[_info.ProxyInfo, bytes], Tuple[None, None]]:
+        """
+        Consume a chunk of data and attempt to parse it.
+
+        @param data: A bytestring.
+        @type data: bytes
+
+        @return: A two-tuple containing, in order, a L{_interfaces.IProxyInfo}
+            and any bytes fed to the parser that followed the end of the
+            header.  Both of these values are None until a complete header is
+            parsed.
+
+        @raises InvalidProxyHeader: If the bytes fed to the parser create an
+            invalid PROXY header.
+        """
+        self.buffer += data
+        if len(self.buffer) < 16:
+            raise InvalidProxyHeader()
+
+        size = struct.unpack("!H", self.buffer[14:16])[0] + 16
+        if len(self.buffer) < size:
+            return (None, None)
+
+        header, remaining = self.buffer[:size], self.buffer[size:]
+        self.buffer = b""
+        info = self.parse(header)
+        return (info, remaining)
+
+    @staticmethod
+    def _bytesToIPv4(bytestring: bytes) -> bytes:
+        """
+        Convert packed 32-bit IPv4 address bytes into a dotted-quad ASCII bytes
+        representation of that address.
+
+        @param bytestring: 4 octets representing an IPv4 address.
+        @type bytestring: L{bytes}
+
+        @return: a dotted-quad notation IPv4 address.
+        @rtype: L{bytes}
+        """
+        return b".".join(
+            ("%i" % (ord(b),)).encode("ascii") for b in compat.iterbytes(bytestring)
+        )
+
+    @staticmethod
+    def _bytesToIPv6(bytestring: bytes) -> bytes:
+        """
+        Convert packed 128-bit IPv6 address bytes into a colon-separated ASCII
+        bytes representation of that address.
+
+        @param bytestring: 16 octets representing an IPv6 address.
+        @type bytestring: L{bytes}
+
+        @return: a dotted-quad notation IPv6 address.
+        @rtype: L{bytes}
+        """
+        hexString = binascii.b2a_hex(bytestring)
+        return b":".join(
+            (f"{int(hexString[b : b + 4], 16):x}").encode("ascii")
+            for b in range(0, 32, 4)
+        )
+
+    @classmethod
+    def parse(cls, line: bytes) -> _info.ProxyInfo:
+        """
+        Parse a bytestring as a full PROXY protocol header.
+
+        @param line: A bytestring that represents a valid HAProxy PROXY
+            protocol version 2 header.
+        @type line: bytes
+
+        @return: A L{_interfaces.IProxyInfo} containing the
+            parsed data.
+
+        @raises InvalidProxyHeader: If the bytestring does not represent a
+            valid PROXY header.
+        """
+        prefix = line[:12]
+        addrInfo = None
+        with convertError(IndexError, InvalidProxyHeader):
+            # Use single value slices to ensure bytestring values are returned
+            # instead of int in PY3.
+            versionCommand = ord(line[12:13])
+            familyProto = ord(line[13:14])
+
+        if prefix != cls.PREFIX:
+            raise InvalidProxyHeader()
+
+        version, command = versionCommand & _HIGH, versionCommand & _LOW
+        if version not in cls.VERSIONS or command not in cls.COMMANDS:
+            raise InvalidProxyHeader()
+
+        if cls.COMMANDS[command] == _LOCALCOMMAND:
+            return _info.ProxyInfo(line, None, None)
+
+        family, netproto = familyProto & _HIGH, familyProto & _LOW
+        with convertError(ValueError, InvalidNetworkProtocol):
+            family = NetFamily.lookupByValue(family)
+            netproto = NetProtocol.lookupByValue(netproto)
+        if family is NetFamily.UNSPEC or netproto is NetProtocol.UNSPEC:
+            return _info.ProxyInfo(line, None, None)
+
+        addressFormat = cls.ADDRESSFORMATS[familyProto]
+        addrInfo = line[16 : 16 + struct.calcsize(addressFormat)]
+        if family is NetFamily.UNIX:
+            with convertError(struct.error, MissingAddressData):
+                source, dest = struct.unpack(addressFormat, addrInfo)
+            return _info.ProxyInfo(
+                line,
+                address.UNIXAddress(source.rstrip(b"\x00")),
+                address.UNIXAddress(dest.rstrip(b"\x00")),
+            )
+
+        addrType: Union[Literal["TCP"], Literal["UDP"]] = "TCP"
+        if netproto is NetProtocol.DGRAM:
+            addrType = "UDP"
+        addrCls: Union[
+            Type[address.IPv4Address], Type[address.IPv6Address]
+        ] = address.IPv4Address
+        addrParser: Callable[[bytes], bytes] = cls._bytesToIPv4
+        if family is NetFamily.INET6:
+            addrCls = address.IPv6Address
+            addrParser = cls._bytesToIPv6
+
+        with convertError(struct.error, MissingAddressData):
+            info = struct.unpack(addressFormat, addrInfo)
+            source, dest, sPort, dPort = info
+
+        return _info.ProxyInfo(
+            line,
+            addrCls(addrType, addrParser(source).decode(), sPort),
+            addrCls(addrType, addrParser(dest).decode(), dPort),
+        )

backend/lib/python3.12/site-packages/twisted/protocols/haproxy/_wrapper.py

@@ -0,0 +1,109 @@
+# -*- test-case-name: twisted.protocols.haproxy.test.test_wrapper -*-
+
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""
+Protocol wrapper that provides HAProxy PROXY protocol support.
+"""
+from typing import Optional, Union
+
+from twisted.internet import interfaces
+from twisted.internet.endpoints import _WrapperServerEndpoint
+from twisted.protocols import policies
+from . import _info
+from ._exceptions import InvalidProxyHeader
+from ._v1parser import V1Parser
+from ._v2parser import V2Parser
+
+
+class HAProxyProtocolWrapper(policies.ProtocolWrapper):
+    """
+    A Protocol wrapper that provides HAProxy support.
+
+    This protocol reads the PROXY stream header, v1 or v2, parses the provided
+    connection data, and modifies the behavior of getPeer and getHost to return
+    the data provided by the PROXY header.
+    """
+
+    def __init__(
+        self, factory: policies.WrappingFactory, wrappedProtocol: interfaces.IProtocol
+    ):
+        super().__init__(factory, wrappedProtocol)
+        self._proxyInfo: Optional[_info.ProxyInfo] = None
+        self._parser: Union[V2Parser, V1Parser, None] = None
+
+    def dataReceived(self, data: bytes) -> None:
+        if self._proxyInfo is not None:
+            return self.wrappedProtocol.dataReceived(data)
+
+        parser = self._parser
+        if parser is None:
+            if (
+                len(data) >= 16
+                and data[:12] == V2Parser.PREFIX
+                and ord(data[12:13]) & 0b11110000 == 0x20
+            ):
+                self._parser = parser = V2Parser()
+            elif len(data) >= 8 and data[:5] == V1Parser.PROXYSTR:
+                self._parser = parser = V1Parser()
+            else:
+                self.loseConnection()
+                return None
+
+        try:
+            self._proxyInfo, remaining = parser.feed(data)
+            if remaining:
+                self.wrappedProtocol.dataReceived(remaining)
+        except InvalidProxyHeader:
+            self.loseConnection()
+
+    def getPeer(self) -> interfaces.IAddress:
+        if self._proxyInfo and self._proxyInfo.source:
+            return self._proxyInfo.source
+        assert self.transport
+        return self.transport.getPeer()
+
+    def getHost(self) -> interfaces.IAddress:
+        if self._proxyInfo and self._proxyInfo.destination:
+            return self._proxyInfo.destination
+        assert self.transport
+        return self.transport.getHost()
+
+
+class HAProxyWrappingFactory(policies.WrappingFactory):
+    """
+    A Factory wrapper that adds PROXY protocol support to connections.
+    """
+
+    protocol = HAProxyProtocolWrapper
+
+    def logPrefix(self) -> str:
+        """
+        Annotate the wrapped factory's log prefix with some text indicating
+        the PROXY protocol is in use.
+
+        @rtype: C{str}
+        """
+        if interfaces.ILoggingContext.providedBy(self.wrappedFactory):
+            logPrefix = self.wrappedFactory.logPrefix()
+        else:
+            logPrefix = self.wrappedFactory.__class__.__name__
+        return f"{logPrefix} (PROXY)"
+
+
+def proxyEndpoint(
+    wrappedEndpoint: interfaces.IStreamServerEndpoint,
+) -> _WrapperServerEndpoint:
+    """
+    Wrap an endpoint with PROXY protocol support, so that the transport's
+    C{getHost} and C{getPeer} methods reflect the attributes of the proxied
+    connection rather than the underlying connection.
+
+    @param wrappedEndpoint: The underlying listening endpoint.
+    @type wrappedEndpoint: L{IStreamServerEndpoint}
+
+    @return: a new listening endpoint that speaks the PROXY protocol.
+    @rtype: L{IStreamServerEndpoint}
+    """
+    return _WrapperServerEndpoint(wrappedEndpoint, HAProxyWrappingFactory)

backend/lib/python3.12/site-packages/twisted/protocols/haproxy/test/__init__.py

@@ -0,0 +1,7 @@
+# -*- test-case-name: twisted.protocols.haproxy.test -*-
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""
+Unit tests for L{twisted.protocols.haproxy}.
+"""

backend/lib/python3.12/site-packages/twisted/protocols/haproxy/test/test_parser.py

@@ -0,0 +1,133 @@
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""
+Tests for L{twisted.protocols.haproxy._parser}.
+"""
+from typing import Type, Union
+
+from twisted.internet.endpoints import (
+    TCP4ServerEndpoint,
+    TCP6ServerEndpoint,
+    UNIXServerEndpoint,
+    _parse as parseEndpoint,
+    _WrapperServerEndpoint,
+    serverFromString,
+)
+from twisted.internet.testing import MemoryReactor
+from twisted.trial.unittest import SynchronousTestCase as TestCase
+from .._parser import unparseEndpoint
+from .._wrapper import HAProxyWrappingFactory
+
+
+class UnparseEndpointTests(TestCase):
+    """
+    Tests to ensure that un-parsing an endpoint string round trips through
+    escaping properly.
+    """
+
+    def check(self, input: str) -> None:
+        """
+        Check that the input unparses into the output, raising an assertion
+        error if it doesn't.
+
+        @param input: an input in endpoint-string-description format.  (To
+            ensure determinism, keyword arguments should be in alphabetical
+            order.)
+        @type input: native L{str}
+        """
+        self.assertEqual(unparseEndpoint(*parseEndpoint(input)), input)
+
+    def test_basicUnparse(self) -> None:
+        """
+        An individual word.
+        """
+        self.check("word")
+
+    def test_multipleArguments(self) -> None:
+        """
+        Multiple arguments.
+        """
+        self.check("one:two")
+
+    def test_keywords(self) -> None:
+        """
+        Keyword arguments.
+        """
+        self.check("aleph=one:bet=two")
+
+    def test_colonInArgument(self) -> None:
+        """
+        Escaped ":".
+        """
+        self.check("hello\\:colon\\:world")
+
+    def test_colonInKeywordValue(self) -> None:
+        """
+        Escaped ":" in keyword value.
+        """
+        self.check("hello=\\:")
+
+    def test_colonInKeywordName(self) -> None:
+        """
+        Escaped ":" in keyword name.
+        """
+        self.check("\\:=hello")
+
+
+class HAProxyServerParserTests(TestCase):
+    """
+    Tests that the parser generates the correct endpoints.
+    """
+
+    def onePrefix(
+        self,
+        description: str,
+        expectedClass: Union[
+            Type[TCP4ServerEndpoint],
+            Type[TCP6ServerEndpoint],
+            Type[UNIXServerEndpoint],
+        ],
+    ) -> _WrapperServerEndpoint:
+        """
+        Test the C{haproxy} enpdoint prefix against one sub-endpoint type.
+
+        @param description: A string endpoint description beginning with
+            C{haproxy}.
+        @type description: native L{str}
+
+        @param expectedClass: the expected sub-endpoint class given the
+            description.
+        @type expectedClass: L{type}
+
+        @return: the parsed endpoint
+        @rtype: L{IStreamServerEndpoint}
+
+        @raise twisted.trial.unittest.Failtest: if the parsed endpoint doesn't
+            match expectations.
+        """
+        reactor = MemoryReactor()
+        endpoint = serverFromString(reactor, description)
+        self.assertIsInstance(endpoint, _WrapperServerEndpoint)
+        assert isinstance(endpoint, _WrapperServerEndpoint)
+        self.assertIsInstance(endpoint._wrappedEndpoint, expectedClass)
+        self.assertIs(endpoint._wrapperFactory, HAProxyWrappingFactory)
+        return endpoint
+
+    def test_tcp4(self) -> None:
+        """
+        Test if the parser generates a wrapped TCP4 endpoint.
+        """
+        self.onePrefix("haproxy:tcp:8080", TCP4ServerEndpoint)
+
+    def test_tcp6(self) -> None:
+        """
+        Test if the parser generates a wrapped TCP6 endpoint.
+        """
+        self.onePrefix("haproxy:tcp6:8080", TCP6ServerEndpoint)
+
+    def test_unix(self) -> None:
+        """
+        Test if the parser generates a wrapped UNIX endpoint.
+        """
+        self.onePrefix("haproxy:unix:address=/tmp/socket", UNIXServerEndpoint)

backend/lib/python3.12/site-packages/twisted/protocols/haproxy/test/test_v1parser.py

@@ -0,0 +1,149 @@
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""
+Test cases for L{twisted.protocols.haproxy.V1Parser}.
+"""
+
+from twisted.internet import address
+from twisted.trial import unittest
+from .. import _v1parser
+from .._exceptions import InvalidNetworkProtocol, InvalidProxyHeader, MissingAddressData
+
+
+class V1ParserTests(unittest.TestCase):
+    """
+    Test L{twisted.protocols.haproxy.V1Parser} behaviour.
+    """
+
+    def test_missingPROXYHeaderValue(self) -> None:
+        """
+        Test that an exception is raised when the PROXY header is missing.
+        """
+        self.assertRaises(
+            InvalidProxyHeader,
+            _v1parser.V1Parser.parse,
+            b"NOTPROXY ",
+        )
+
+    def test_invalidNetworkProtocol(self) -> None:
+        """
+        Test that an exception is raised when the proto is not TCP or UNKNOWN.
+        """
+        self.assertRaises(
+            InvalidNetworkProtocol,
+            _v1parser.V1Parser.parse,
+            b"PROXY WUTPROTO ",
+        )
+
+    def test_missingSourceData(self) -> None:
+        """
+        Test that an exception is raised when the proto has no source data.
+        """
+        self.assertRaises(
+            MissingAddressData,
+            _v1parser.V1Parser.parse,
+            b"PROXY TCP4 ",
+        )
+
+    def test_missingDestData(self) -> None:
+        """
+        Test that an exception is raised when the proto has no destination.
+        """
+        self.assertRaises(
+            MissingAddressData,
+            _v1parser.V1Parser.parse,
+            b"PROXY TCP4 127.0.0.1 8080 8888",
+        )
+
+    def test_fullParsingSuccess(self) -> None:
+        """
+        Test that parsing is successful for a PROXY header.
+        """
+        info = _v1parser.V1Parser.parse(
+            b"PROXY TCP4 127.0.0.1 127.0.0.1 8080 8888",
+        )
+        self.assertIsInstance(info.source, address.IPv4Address)
+        assert isinstance(info.source, address.IPv4Address)
+        assert isinstance(info.destination, address.IPv4Address)  # type: ignore[unreachable]
+        self.assertEqual(info.source.host, "127.0.0.1")
+        self.assertEqual(info.source.port, 8080)
+        self.assertEqual(info.destination.host, "127.0.0.1")
+        self.assertEqual(info.destination.port, 8888)
+
+    def test_fullParsingSuccess_IPv6(self) -> None:
+        """
+        Test that parsing is successful for an IPv6 PROXY header.
+        """
+        info = _v1parser.V1Parser.parse(
+            b"PROXY TCP6 ::1 ::1 8080 8888",
+        )
+        self.assertIsInstance(info.source, address.IPv6Address)
+        assert isinstance(info.source, address.IPv6Address)
+        assert isinstance(info.destination, address.IPv6Address)  # type: ignore[unreachable]
+        self.assertEqual(info.source.host, "::1")
+        self.assertEqual(info.source.port, 8080)
+        self.assertEqual(info.destination.host, "::1")
+        self.assertEqual(info.destination.port, 8888)
+
+    def test_fullParsingSuccess_UNKNOWN(self) -> None:
+        """
+        Test that parsing is successful for a UNKNOWN PROXY header.
+        """
+        info = _v1parser.V1Parser.parse(
+            b"PROXY UNKNOWN anything could go here",
+        )
+        self.assertIsNone(info.source)
+        self.assertIsNone(info.destination)
+
+    def test_feedParsing(self) -> None:
+        """
+        Test that parsing happens when fed a complete line.
+        """
+        parser = _v1parser.V1Parser()
+        info, remaining = parser.feed(b"PROXY TCP4 127.0.0.1 127.0.0.1 ")
+        self.assertFalse(info)
+        self.assertFalse(remaining)
+        info, remaining = parser.feed(b"8080 8888")
+        self.assertFalse(info)
+        self.assertFalse(remaining)
+        info, remaining = parser.feed(b"\r\n")
+        self.assertFalse(remaining)
+        assert remaining is not None
+        assert info is not None
+        self.assertIsInstance(info.source, address.IPv4Address)
+        assert isinstance(info.source, address.IPv4Address)
+        assert isinstance(info.destination, address.IPv4Address)  # type: ignore[unreachable]
+        self.assertEqual(info.source.host, "127.0.0.1")
+        self.assertEqual(info.source.port, 8080)
+        self.assertEqual(info.destination.host, "127.0.0.1")
+        self.assertEqual(info.destination.port, 8888)
+
+    def test_feedParsingTooLong(self) -> None:
+        """
+        Test that parsing fails if no newline is found in 108 bytes.
+        """
+        parser = _v1parser.V1Parser()
+        info, remaining = parser.feed(b"PROXY TCP4 127.0.0.1 127.0.0.1 ")
+        self.assertFalse(info)
+        self.assertFalse(remaining)
+        info, remaining = parser.feed(b"8080 8888")
+        self.assertFalse(info)
+        self.assertFalse(remaining)
+        self.assertRaises(
+            InvalidProxyHeader,
+            parser.feed,
+            b" " * 100,
+        )
+
+    def test_feedParsingOverflow(self) -> None:
+        """
+        Test that parsing leaves overflow bytes in the buffer.
+        """
+        parser = _v1parser.V1Parser()
+        info, remaining = parser.feed(
+            b"PROXY TCP4 127.0.0.1 127.0.0.1 8080 8888\r\nHTTP/1.1 GET /\r\n",
+        )
+        self.assertTrue(info)
+        self.assertEqual(remaining, b"HTTP/1.1 GET /\r\n")
+        self.assertFalse(parser.buffer)

backend/lib/python3.12/site-packages/twisted/protocols/haproxy/test/test_v2parser.py

@@ -0,0 +1,368 @@
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""
+Test cases for L{twisted.protocols.haproxy.V2Parser}.
+"""
+
+from twisted.internet import address
+from twisted.trial import unittest
+from .. import _v2parser
+from .._exceptions import InvalidProxyHeader
+
+V2_SIGNATURE = b"\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A"
+
+
+def _makeHeaderIPv6(
+    sig: bytes = V2_SIGNATURE,
+    verCom: bytes = b"\x21",
+    famProto: bytes = b"\x21",
+    addrLength: bytes = b"\x00\x24",
+    addrs: bytes = ((b"\x00" * 15) + b"\x01") * 2,
+    ports: bytes = b"\x1F\x90\x22\xB8",
+) -> bytes:
+    """
+    Construct a version 2 IPv6 header with custom bytes.
+
+    @param sig: The protocol signature; defaults to valid L{V2_SIGNATURE}.
+    @type sig: L{bytes}
+
+    @param verCom: Protocol version and command.  Defaults to V2 PROXY.
+    @type verCom: L{bytes}
+
+    @param famProto: Address family and protocol.  Defaults to AF_INET6/STREAM.
+    @type famProto: L{bytes}
+
+    @param addrLength: Network-endian byte length of payload.  Defaults to
+        description of default addrs/ports.
+    @type addrLength: L{bytes}
+
+    @param addrs: Address payload.  Defaults to C{::1} for source and
+        destination.
+    @type addrs: L{bytes}
+
+    @param ports: Source and destination ports.  Defaults to 8080 for source
+        8888 for destination.
+    @type ports: L{bytes}
+
+    @return: A packet with header, addresses, and ports.
+    @rtype: L{bytes}
+    """
+    return sig + verCom + famProto + addrLength + addrs + ports
+
+
+def _makeHeaderIPv4(
+    sig: bytes = V2_SIGNATURE,
+    verCom: bytes = b"\x21",
+    famProto: bytes = b"\x11",
+    addrLength: bytes = b"\x00\x0C",
+    addrs: bytes = b"\x7F\x00\x00\x01\x7F\x00\x00\x01",
+    ports: bytes = b"\x1F\x90\x22\xB8",
+) -> bytes:
+    """
+    Construct a version 2 IPv4 header with custom bytes.
+
+    @param sig: The protocol signature; defaults to valid L{V2_SIGNATURE}.
+    @type sig: L{bytes}
+
+    @param verCom: Protocol version and command.  Defaults to V2 PROXY.
+    @type verCom: L{bytes}
+
+    @param famProto: Address family and protocol.  Defaults to AF_INET/STREAM.
+    @type famProto: L{bytes}
+
+    @param addrLength: Network-endian byte length of payload.  Defaults to
+        description of default addrs/ports.
+    @type addrLength: L{bytes}
+
+    @param addrs: Address payload.  Defaults to 127.0.0.1 for source and
+        destination.
+    @type addrs: L{bytes}
+
+    @param ports: Source and destination ports.  Defaults to 8080 for source
+        8888 for destination.
+    @type ports: L{bytes}
+
+    @return: A packet with header, addresses, and ports.
+    @rtype: L{bytes}
+    """
+    return sig + verCom + famProto + addrLength + addrs + ports
+
+
+def _makeHeaderUnix(
+    sig: bytes = V2_SIGNATURE,
+    verCom: bytes = b"\x21",
+    famProto: bytes = b"\x31",
+    addrLength: bytes = b"\x00\xD8",
+    addrs: bytes = (
+        b"\x2F\x68\x6F\x6D\x65\x2F\x74\x65\x73\x74\x73\x2F"
+        b"\x6D\x79\x73\x6F\x63\x6B\x65\x74\x73\x2F\x73\x6F"
+        b"\x63\x6B" + (b"\x00" * 82)
+    )
+    * 2,
+) -> bytes:
+    """
+    Construct a version 2 IPv4 header with custom bytes.
+
+    @param sig: The protocol signature; defaults to valid L{V2_SIGNATURE}.
+    @type sig: L{bytes}
+
+    @param verCom: Protocol version and command.  Defaults to V2 PROXY.
+    @type verCom: L{bytes}
+
+    @param famProto: Address family and protocol.  Defaults to AF_UNIX/STREAM.
+    @type famProto: L{bytes}
+
+    @param addrLength: Network-endian byte length of payload.  Defaults to 108
+        bytes for 2 null terminated paths.
+    @type addrLength: L{bytes}
+
+    @param addrs: Address payload.  Defaults to C{/home/tests/mysockets/sock}
+        for source and destination paths.
+    @type addrs: L{bytes}
+
+    @return: A packet with header, addresses, and8 ports.
+    @rtype: L{bytes}
+    """
+    return sig + verCom + famProto + addrLength + addrs
+
+
+class V2ParserTests(unittest.TestCase):
+    """
+    Test L{twisted.protocols.haproxy.V2Parser} behaviour.
+    """
+
+    def test_happyPathIPv4(self) -> None:
+        """
+        Test if a well formed IPv4 header is parsed without error.
+        """
+        header = _makeHeaderIPv4()
+        self.assertTrue(_v2parser.V2Parser.parse(header))
+
+    def test_happyPathIPv6(self) -> None:
+        """
+        Test if a well formed IPv6 header is parsed without error.
+        """
+        header = _makeHeaderIPv6()
+        self.assertTrue(_v2parser.V2Parser.parse(header))
+
+    def test_happyPathUnix(self) -> None:
+        """
+        Test if a well formed UNIX header is parsed without error.
+        """
+        header = _makeHeaderUnix()
+        self.assertTrue(_v2parser.V2Parser.parse(header))
+
+    def test_invalidSignature(self) -> None:
+        """
+        Test if an invalid signature block raises InvalidProxyError.
+        """
+        header = _makeHeaderIPv4(sig=b"\x00" * 12)
+        self.assertRaises(
+            InvalidProxyHeader,
+            _v2parser.V2Parser.parse,
+            header,
+        )
+
+    def test_invalidVersion(self) -> None:
+        """
+        Test if an invalid version raises InvalidProxyError.
+        """
+        header = _makeHeaderIPv4(verCom=b"\x11")
+        self.assertRaises(
+            InvalidProxyHeader,
+            _v2parser.V2Parser.parse,
+            header,
+        )
+
+    def test_invalidCommand(self) -> None:
+        """
+        Test if an invalid command raises InvalidProxyError.
+        """
+        header = _makeHeaderIPv4(verCom=b"\x23")
+        self.assertRaises(
+            InvalidProxyHeader,
+            _v2parser.V2Parser.parse,
+            header,
+        )
+
+    def test_invalidFamily(self) -> None:
+        """
+        Test if an invalid family raises InvalidProxyError.
+        """
+        header = _makeHeaderIPv4(famProto=b"\x40")
+        self.assertRaises(
+            InvalidProxyHeader,
+            _v2parser.V2Parser.parse,
+            header,
+        )
+
+    def test_invalidProto(self) -> None:
+        """
+        Test if an invalid protocol raises InvalidProxyError.
+        """
+        header = _makeHeaderIPv4(famProto=b"\x24")
+        self.assertRaises(
+            InvalidProxyHeader,
+            _v2parser.V2Parser.parse,
+            header,
+        )
+
+    def test_localCommandIpv4(self) -> None:
+        """
+        Test that local does not return endpoint data for IPv4 connections.
+        """
+        header = _makeHeaderIPv4(verCom=b"\x20")
+        info = _v2parser.V2Parser.parse(header)
+        self.assertFalse(info.source)
+        self.assertFalse(info.destination)
+
+    def test_localCommandIpv6(self) -> None:
+        """
+        Test that local does not return endpoint data for IPv6 connections.
+        """
+        header = _makeHeaderIPv6(verCom=b"\x20")
+        info = _v2parser.V2Parser.parse(header)
+        self.assertFalse(info.source)
+        self.assertFalse(info.destination)
+
+    def test_localCommandUnix(self) -> None:
+        """
+        Test that local does not return endpoint data for UNIX connections.
+        """
+        header = _makeHeaderUnix(verCom=b"\x20")
+        info = _v2parser.V2Parser.parse(header)
+        self.assertFalse(info.source)
+        self.assertFalse(info.destination)
+
+    def test_proxyCommandIpv4(self) -> None:
+        """
+        Test that proxy returns endpoint data for IPv4 connections.
+        """
+        header = _makeHeaderIPv4(verCom=b"\x21")
+        info = _v2parser.V2Parser.parse(header)
+        self.assertTrue(info.source)
+        self.assertIsInstance(info.source, address.IPv4Address)
+        self.assertTrue(info.destination)
+        self.assertIsInstance(info.destination, address.IPv4Address)
+
+    def test_proxyCommandIpv6(self) -> None:
+        """
+        Test that proxy returns endpoint data for IPv6 connections.
+        """
+        header = _makeHeaderIPv6(verCom=b"\x21")
+        info = _v2parser.V2Parser.parse(header)
+        self.assertTrue(info.source)
+        self.assertIsInstance(info.source, address.IPv6Address)
+        self.assertTrue(info.destination)
+        self.assertIsInstance(info.destination, address.IPv6Address)
+
+    def test_proxyCommandUnix(self) -> None:
+        """
+        Test that proxy returns endpoint data for UNIX connections.
+        """
+        header = _makeHeaderUnix(verCom=b"\x21")
+        info = _v2parser.V2Parser.parse(header)
+        self.assertTrue(info.source)
+        self.assertIsInstance(info.source, address.UNIXAddress)
+        self.assertTrue(info.destination)
+        self.assertIsInstance(info.destination, address.UNIXAddress)
+
+    def test_unspecFamilyIpv4(self) -> None:
+        """
+        Test that UNSPEC does not return endpoint data for IPv4 connections.
+        """
+        header = _makeHeaderIPv4(famProto=b"\x01")
+        info = _v2parser.V2Parser.parse(header)
+        self.assertFalse(info.source)
+        self.assertFalse(info.destination)
+
+    def test_unspecFamilyIpv6(self) -> None:
+        """
+        Test that UNSPEC does not return endpoint data for IPv6 connections.
+        """
+        header = _makeHeaderIPv6(famProto=b"\x01")
+        info = _v2parser.V2Parser.parse(header)
+        self.assertFalse(info.source)
+        self.assertFalse(info.destination)
+
+    def test_unspecFamilyUnix(self) -> None:
+        """
+        Test that UNSPEC does not return endpoint data for UNIX connections.
+        """
+        header = _makeHeaderUnix(famProto=b"\x01")
+        info = _v2parser.V2Parser.parse(header)
+        self.assertFalse(info.source)
+        self.assertFalse(info.destination)
+
+    def test_unspecProtoIpv4(self) -> None:
+        """
+        Test that UNSPEC does not return endpoint data for IPv4 connections.
+        """
+        header = _makeHeaderIPv4(famProto=b"\x10")
+        info = _v2parser.V2Parser.parse(header)
+        self.assertFalse(info.source)
+        self.assertFalse(info.destination)
+
+    def test_unspecProtoIpv6(self) -> None:
+        """
+        Test that UNSPEC does not return endpoint data for IPv6 connections.
+        """
+        header = _makeHeaderIPv6(famProto=b"\x20")
+        info = _v2parser.V2Parser.parse(header)
+        self.assertFalse(info.source)
+        self.assertFalse(info.destination)
+
+    def test_unspecProtoUnix(self) -> None:
+        """
+        Test that UNSPEC does not return endpoint data for UNIX connections.
+        """
+        header = _makeHeaderUnix(famProto=b"\x30")
+        info = _v2parser.V2Parser.parse(header)
+        self.assertFalse(info.source)
+        self.assertFalse(info.destination)
+
+    def test_overflowIpv4(self) -> None:
+        """
+        Test that overflow bits are preserved during feed parsing for IPv4.
+        """
+        testValue = b"TEST DATA\r\n\r\nTEST DATA"
+        header = _makeHeaderIPv4() + testValue
+        parser = _v2parser.V2Parser()
+        info, overflow = parser.feed(header)
+        self.assertTrue(info)
+        self.assertEqual(overflow, testValue)
+
+    def test_overflowIpv6(self) -> None:
+        """
+        Test that overflow bits are preserved during feed parsing for IPv6.
+        """
+        testValue = b"TEST DATA\r\n\r\nTEST DATA"
+        header = _makeHeaderIPv6() + testValue
+        parser = _v2parser.V2Parser()
+        info, overflow = parser.feed(header)
+        self.assertTrue(info)
+        self.assertEqual(overflow, testValue)
+
+    def test_overflowUnix(self) -> None:
+        """
+        Test that overflow bits are preserved during feed parsing for Unix.
+        """
+        testValue = b"TEST DATA\r\n\r\nTEST DATA"
+        header = _makeHeaderUnix() + testValue
+        parser = _v2parser.V2Parser()
+        info, overflow = parser.feed(header)
+        self.assertTrue(info)
+        self.assertEqual(overflow, testValue)
+
+    def test_segmentTooSmall(self) -> None:
+        """
+        Test that an initial payload of less than 16 bytes fails.
+        """
+        testValue = b"NEEDMOREDATA"
+        parser = _v2parser.V2Parser()
+        self.assertRaises(
+            InvalidProxyHeader,
+            parser.feed,
+            testValue,
+        )

backend/lib/python3.12/site-packages/twisted/protocols/haproxy/test/test_wrapper.py

@@ -0,0 +1,375 @@
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""
+Test cases for L{twisted.protocols.haproxy.HAProxyProtocol}.
+"""
+from typing import Optional
+from unittest import mock
+
+from twisted.internet import address
+from twisted.internet.protocol import Factory, Protocol
+from twisted.internet.testing import StringTransportWithDisconnection
+from twisted.trial import unittest
+from .._wrapper import HAProxyWrappingFactory
+
+
+class StaticProtocol(Protocol):
+    """
+    Protocol stand-in that maintains test state.
+    """
+
+    def __init__(self) -> None:
+        self.source: Optional[address.IAddress] = None
+        self.destination: Optional[address.IAddress] = None
+        self.data = b""
+        self.disconnected = False
+
+    def dataReceived(self, data: bytes) -> None:
+        assert self.transport
+        self.source = self.transport.getPeer()
+        self.destination = self.transport.getHost()
+        self.data += data
+
+
+class HAProxyWrappingFactoryV1Tests(unittest.TestCase):
+    """
+    Test L{twisted.protocols.haproxy.HAProxyWrappingFactory} with v1 PROXY
+    headers.
+    """
+
+    def test_invalidHeaderDisconnects(self) -> None:
+        """
+        Test if invalid headers result in connectionLost events.
+        """
+        factory = HAProxyWrappingFactory(Factory.forProtocol(StaticProtocol))
+        proto = factory.buildProtocol(
+            address.IPv4Address("TCP", "127.1.1.1", 8080),
+        )
+        transport = StringTransportWithDisconnection()
+        transport.protocol = proto
+        proto.makeConnection(transport)
+        proto.dataReceived(b"NOTPROXY anything can go here\r\n")
+        self.assertFalse(transport.connected)
+
+    def test_invalidPartialHeaderDisconnects(self) -> None:
+        """
+        Test if invalid headers result in connectionLost events.
+        """
+        factory = HAProxyWrappingFactory(Factory.forProtocol(StaticProtocol))
+        proto = factory.buildProtocol(
+            address.IPv4Address("TCP", "127.1.1.1", 8080),
+        )
+        transport = StringTransportWithDisconnection()
+        transport.protocol = proto
+        proto.makeConnection(transport)
+        proto.dataReceived(b"PROXY TCP4 1.1.1.1\r\n")
+        proto.dataReceived(b"2.2.2.2 8080\r\n")
+        self.assertFalse(transport.connected)
+
+    def test_preDataReceived_getPeerHost(self) -> None:
+        """
+        Before any data is received the HAProxy protocol will return the same peer
+        and host as the IP connection.
+        """
+        factory = HAProxyWrappingFactory(Factory.forProtocol(StaticProtocol))
+        proto = factory.buildProtocol(
+            address.IPv4Address("TCP", "127.0.0.1", 8080),
+        )
+        transport = StringTransportWithDisconnection(
+            hostAddress=mock.sentinel.host_address,
+            peerAddress=mock.sentinel.peer_address,
+        )
+        proto.makeConnection(transport)
+        self.assertEqual(proto.getHost(), mock.sentinel.host_address)
+        self.assertEqual(proto.getPeer(), mock.sentinel.peer_address)
+
+    def test_validIPv4HeaderResolves_getPeerHost(self) -> None:
+        """
+        Test if IPv4 headers result in the correct host and peer data.
+        """
+        factory = HAProxyWrappingFactory(Factory.forProtocol(StaticProtocol))
+        proto = factory.buildProtocol(
+            address.IPv4Address("TCP", "127.0.0.1", 8080),
+        )
+        transport = StringTransportWithDisconnection()
+        proto.makeConnection(transport)
+        proto.dataReceived(b"PROXY TCP4 1.1.1.1 2.2.2.2 8080 8888\r\n")
+        self.assertEqual(proto.getPeer().host, "1.1.1.1")
+        self.assertEqual(proto.getPeer().port, 8080)
+        self.assertEqual(
+            proto.wrappedProtocol.transport.getPeer().host,
+            "1.1.1.1",
+        )
+        self.assertEqual(
+            proto.wrappedProtocol.transport.getPeer().port,
+            8080,
+        )
+        self.assertEqual(proto.getHost().host, "2.2.2.2")
+        self.assertEqual(proto.getHost().port, 8888)
+        self.assertEqual(
+            proto.wrappedProtocol.transport.getHost().host,
+            "2.2.2.2",
+        )
+        self.assertEqual(
+            proto.wrappedProtocol.transport.getHost().port,
+            8888,
+        )
+
+    def test_validIPv6HeaderResolves_getPeerHost(self) -> None:
+        """
+        Test if IPv6 headers result in the correct host and peer data.
+        """
+        factory = HAProxyWrappingFactory(Factory.forProtocol(StaticProtocol))
+        proto = factory.buildProtocol(
+            address.IPv6Address("TCP", "::1", 8080),
+        )
+        transport = StringTransportWithDisconnection()
+        proto.makeConnection(transport)
+        proto.dataReceived(b"PROXY TCP6 ::1 ::2 8080 8888\r\n")
+        self.assertEqual(proto.getPeer().host, "::1")
+        self.assertEqual(proto.getPeer().port, 8080)
+        self.assertEqual(
+            proto.wrappedProtocol.transport.getPeer().host,
+            "::1",
+        )
+        self.assertEqual(
+            proto.wrappedProtocol.transport.getPeer().port,
+            8080,
+        )
+        self.assertEqual(proto.getHost().host, "::2")
+        self.assertEqual(proto.getHost().port, 8888)
+        self.assertEqual(
+            proto.wrappedProtocol.transport.getHost().host,
+            "::2",
+        )
+        self.assertEqual(
+            proto.wrappedProtocol.transport.getHost().port,
+            8888,
+        )
+
+    def test_overflowBytesSentToWrappedProtocol(self) -> None:
+        """
+        Test if non-header bytes are passed to the wrapped protocol.
+        """
+        factory = HAProxyWrappingFactory(Factory.forProtocol(StaticProtocol))
+        proto = factory.buildProtocol(
+            address.IPv6Address("TCP", "::1", 8080),
+        )
+        transport = StringTransportWithDisconnection()
+        proto.makeConnection(transport)
+        proto.dataReceived(b"PROXY TCP6 ::1 ::2 8080 8888\r\nHTTP/1.1 / GET")
+        self.assertEqual(proto.wrappedProtocol.data, b"HTTP/1.1 / GET")
+
+    def test_overflowBytesSentToWrappedProtocolChunks(self) -> None:
+        """
+        Test if header streaming passes extra data appropriately.
+        """
+        factory = HAProxyWrappingFactory(Factory.forProtocol(StaticProtocol))
+        proto = factory.buildProtocol(
+            address.IPv6Address("TCP", "::1", 8080),
+        )
+        transport = StringTransportWithDisconnection()
+        proto.makeConnection(transport)
+        proto.dataReceived(b"PROXY TCP6 ::1 ::2 ")
+        proto.dataReceived(b"8080 8888\r\nHTTP/1.1 / GET")
+        self.assertEqual(proto.wrappedProtocol.data, b"HTTP/1.1 / GET")
+
+    def test_overflowBytesSentToWrappedProtocolAfter(self) -> None:
+        """
+        Test if wrapper writes all data to wrapped protocol after parsing.
+        """
+        factory = HAProxyWrappingFactory(Factory.forProtocol(StaticProtocol))
+        proto = factory.buildProtocol(
+            address.IPv6Address("TCP", "::1", 8080),
+        )
+        transport = StringTransportWithDisconnection()
+        proto.makeConnection(transport)
+        proto.dataReceived(b"PROXY TCP6 ::1 ::2 ")
+        proto.dataReceived(b"8080 8888\r\nHTTP/1.1 / GET")
+        proto.dataReceived(b"\r\n\r\n")
+        self.assertEqual(proto.wrappedProtocol.data, b"HTTP/1.1 / GET\r\n\r\n")
+
+
+class HAProxyWrappingFactoryV2Tests(unittest.TestCase):
+    """
+    Test L{twisted.protocols.haproxy.HAProxyWrappingFactory} with v2 PROXY
+    headers.
+    """
+
+    IPV4HEADER = (
+        # V2 Signature
+        b"\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A"
+        # V2 PROXY command
+        b"\x21"
+        # AF_INET/STREAM
+        b"\x11"
+        # 12 bytes for 2 IPv4 addresses and two ports
+        b"\x00\x0C"
+        # 127.0.0.1 for source and destination
+        b"\x7F\x00\x00\x01\x7F\x00\x00\x01"
+        # 8080 for source 8888 for destination
+        b"\x1F\x90\x22\xB8"
+    )
+    IPV6HEADER = (
+        # V2 Signature
+        b"\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A"
+        # V2 PROXY command
+        b"\x21"
+        # AF_INET6/STREAM
+        b"\x21"
+        # 16 bytes for 2 IPv6 addresses and two ports
+        b"\x00\x24"
+        # ::1 for source and destination
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01"
+        b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01"
+        # 8080 for source 8888 for destination
+        b"\x1F\x90\x22\xB8"
+    )
+
+    _SOCK_PATH = (
+        b"\x2F\x68\x6F\x6D\x65\x2F\x74\x65\x73\x74\x73\x2F\x6D\x79\x73\x6F"
+        b"\x63\x6B\x65\x74\x73\x2F\x73\x6F\x63\x6B" + (b"\x00" * 82)
+    )
+    UNIXHEADER = (
+        (
+            # V2 Signature
+            b"\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A"
+            # V2 PROXY command
+            b"\x21"
+            # AF_UNIX/STREAM
+            b"\x31"
+            # 108 bytes for 2 null terminated paths
+            b"\x00\xD8"
+            # /home/tests/mysockets/sock for source and destination paths
+        )
+        + _SOCK_PATH
+        + _SOCK_PATH
+    )
+
+    def test_invalidHeaderDisconnects(self) -> None:
+        """
+        Test if invalid headers result in connectionLost events.
+        """
+        factory = HAProxyWrappingFactory(Factory.forProtocol(StaticProtocol))
+        proto = factory.buildProtocol(
+            address.IPv6Address("TCP", "::1", 8080),
+        )
+        transport = StringTransportWithDisconnection()
+        transport.protocol = proto
+        proto.makeConnection(transport)
+        proto.dataReceived(b"\x00" + self.IPV4HEADER[1:])
+        self.assertFalse(transport.connected)
+
+    def test_validIPv4HeaderResolves_getPeerHost(self) -> None:
+        """
+        Test if IPv4 headers result in the correct host and peer data.
+        """
+        factory = HAProxyWrappingFactory(Factory.forProtocol(StaticProtocol))
+        proto = factory.buildProtocol(
+            address.IPv4Address("TCP", "127.0.0.1", 8080),
+        )
+        transport = StringTransportWithDisconnection()
+        proto.makeConnection(transport)
+        proto.dataReceived(self.IPV4HEADER)
+        self.assertEqual(proto.getPeer().host, "127.0.0.1")
+        self.assertEqual(proto.getPeer().port, 8080)
+        self.assertEqual(
+            proto.wrappedProtocol.transport.getPeer().host,
+            "127.0.0.1",
+        )
+        self.assertEqual(
+            proto.wrappedProtocol.transport.getPeer().port,
+            8080,
+        )
+        self.assertEqual(proto.getHost().host, "127.0.0.1")
+        self.assertEqual(proto.getHost().port, 8888)
+        self.assertEqual(
+            proto.wrappedProtocol.transport.getHost().host,
+            "127.0.0.1",
+        )
+        self.assertEqual(
+            proto.wrappedProtocol.transport.getHost().port,
+            8888,
+        )
+
+    def test_validIPv6HeaderResolves_getPeerHost(self) -> None:
+        """
+        Test if IPv6 headers result in the correct host and peer data.
+        """
+        factory = HAProxyWrappingFactory(Factory.forProtocol(StaticProtocol))
+        proto = factory.buildProtocol(
+            address.IPv4Address("TCP", "::1", 8080),
+        )
+        transport = StringTransportWithDisconnection()
+        proto.makeConnection(transport)
+        proto.dataReceived(self.IPV6HEADER)
+        self.assertEqual(proto.getPeer().host, "0:0:0:0:0:0:0:1")
+        self.assertEqual(proto.getPeer().port, 8080)
+        self.assertEqual(
+            proto.wrappedProtocol.transport.getPeer().host,
+            "0:0:0:0:0:0:0:1",
+        )
+        self.assertEqual(
+            proto.wrappedProtocol.transport.getPeer().port,
+            8080,
+        )
+        self.assertEqual(proto.getHost().host, "0:0:0:0:0:0:0:1")
+        self.assertEqual(proto.getHost().port, 8888)
+        self.assertEqual(
+            proto.wrappedProtocol.transport.getHost().host,
+            "0:0:0:0:0:0:0:1",
+        )
+        self.assertEqual(
+            proto.wrappedProtocol.transport.getHost().port,
+            8888,
+        )
+
+    def test_validUNIXHeaderResolves_getPeerHost(self) -> None:
+        """
+        Test if UNIX headers result in the correct host and peer data.
+        """
+        factory = HAProxyWrappingFactory(Factory.forProtocol(StaticProtocol))
+        proto = factory.buildProtocol(
+            address.UNIXAddress(b"/home/test/sockets/server.sock"),
+        )
+        transport = StringTransportWithDisconnection()
+        proto.makeConnection(transport)
+        proto.dataReceived(self.UNIXHEADER)
+        self.assertEqual(proto.getPeer().name, b"/home/tests/mysockets/sock")
+        self.assertEqual(
+            proto.wrappedProtocol.transport.getPeer().name,
+            b"/home/tests/mysockets/sock",
+        )
+        self.assertEqual(proto.getHost().name, b"/home/tests/mysockets/sock")
+        self.assertEqual(
+            proto.wrappedProtocol.transport.getHost().name,
+            b"/home/tests/mysockets/sock",
+        )
+
+    def test_overflowBytesSentToWrappedProtocol(self) -> None:
+        """
+        Test if non-header bytes are passed to the wrapped protocol.
+        """
+        factory = HAProxyWrappingFactory(Factory.forProtocol(StaticProtocol))
+        proto = factory.buildProtocol(
+            address.IPv6Address("TCP", "::1", 8080),
+        )
+        transport = StringTransportWithDisconnection()
+        proto.makeConnection(transport)
+        proto.dataReceived(self.IPV6HEADER + b"HTTP/1.1 / GET")
+        self.assertEqual(proto.wrappedProtocol.data, b"HTTP/1.1 / GET")
+
+    def test_overflowBytesSentToWrappedProtocolChunks(self) -> None:
+        """
+        Test if header streaming passes extra data appropriately.
+        """
+        factory = HAProxyWrappingFactory(Factory.forProtocol(StaticProtocol))
+        proto = factory.buildProtocol(
+            address.IPv6Address("TCP", "::1", 8080),
+        )
+        transport = StringTransportWithDisconnection()
+        proto.makeConnection(transport)
+        proto.dataReceived(self.IPV6HEADER[:18])
+        proto.dataReceived(self.IPV6HEADER[18:] + b"HTTP/1.1 / GET")
+        self.assertEqual(proto.wrappedProtocol.data, b"HTTP/1.1 / GET")

backend/lib/python3.12/site-packages/twisted/protocols/htb.py

@@ -0,0 +1,306 @@
+# -*- test-case-name: twisted.test.test_htb -*-
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+
+"""
+Hierarchical Token Bucket traffic shaping.
+
+Patterned after U{Martin Devera's Hierarchical Token Bucket traffic
+shaper for the Linux kernel<http://luxik.cdi.cz/~devik/qos/htb/>}.
+
+@seealso: U{HTB Linux queuing discipline manual - user guide
+  <http://luxik.cdi.cz/~devik/qos/htb/manual/userg.htm>}
+@seealso: U{Token Bucket Filter in Linux Advanced Routing & Traffic Control
+    HOWTO<http://lartc.org/howto/lartc.qdisc.classless.html#AEN682>}
+"""
+
+
+# TODO: Investigate whether we should be using os.times()[-1] instead of
+# time.time.  time.time, it has been pointed out, can go backwards.  Is
+# the same true of os.times?
+from time import time
+from typing import Optional
+
+from zope.interface import Interface, implementer
+
+from twisted.protocols import pcp
+
+
+class Bucket:
+    """
+    Implementation of a Token bucket.
+
+    A bucket can hold a certain number of tokens and it drains over time.
+
+    @cvar maxburst: The maximum number of tokens that the bucket can
+        hold at any given time. If this is L{None}, the bucket has
+        an infinite size.
+    @type maxburst: C{int}
+    @cvar rate: The rate at which the bucket drains, in number
+        of tokens per second. If the rate is L{None}, the bucket
+        drains instantaneously.
+    @type rate: C{int}
+    """
+
+    maxburst: Optional[int] = None
+    rate: Optional[int] = None
+
+    _refcount = 0
+
+    def __init__(self, parentBucket=None):
+        """
+        Create a L{Bucket} that may have a parent L{Bucket}.
+
+        @param parentBucket: If a parent Bucket is specified,
+            all L{add} and L{drip} operations on this L{Bucket}
+            will be applied on the parent L{Bucket} as well.
+        @type parentBucket: L{Bucket}
+        """
+        self.content = 0
+        self.parentBucket = parentBucket
+        self.lastDrip = time()
+
+    def add(self, amount):
+        """
+        Adds tokens to the L{Bucket} and its C{parentBucket}.
+
+        This will add as many of the C{amount} tokens as will fit into both
+        this L{Bucket} and its C{parentBucket}.
+
+        @param amount: The number of tokens to try to add.
+        @type amount: C{int}
+
+        @returns: The number of tokens that actually fit.
+        @returntype: C{int}
+        """
+        self.drip()
+        if self.maxburst is None:
+            allowable = amount
+        else:
+            allowable = min(amount, self.maxburst - self.content)
+
+        if self.parentBucket is not None:
+            allowable = self.parentBucket.add(allowable)
+        self.content += allowable
+        return allowable
+
+    def drip(self):
+        """
+        Let some of the bucket drain.
+
+        The L{Bucket} drains at the rate specified by the class
+        variable C{rate}.
+
+        @returns: C{True} if the bucket is empty after this drip.
+        @returntype: C{bool}
+        """
+        if self.parentBucket is not None:
+            self.parentBucket.drip()
+
+        if self.rate is None:
+            self.content = 0
+        else:
+            now = time()
+            deltaTime = now - self.lastDrip
+            deltaTokens = deltaTime * self.rate
+            self.content = max(0, self.content - deltaTokens)
+            self.lastDrip = now
+        return self.content == 0
+
+
+class IBucketFilter(Interface):
+    def getBucketFor(*somethings, **some_kw):
+        """
+        Return a L{Bucket} corresponding to the provided parameters.
+
+        @returntype: L{Bucket}
+        """
+
+
+@implementer(IBucketFilter)
+class HierarchicalBucketFilter:
+    """
+    Filter things into buckets that can be nested.
+
+    @cvar bucketFactory: Class of buckets to make.
+    @type bucketFactory: L{Bucket}
+    @cvar sweepInterval: Seconds between sweeping out the bucket cache.
+    @type sweepInterval: C{int}
+    """
+
+    bucketFactory = Bucket
+    sweepInterval: Optional[int] = None
+
+    def __init__(self, parentFilter=None):
+        self.buckets = {}
+        self.parentFilter = parentFilter
+        self.lastSweep = time()
+
+    def getBucketFor(self, *a, **kw):
+        """
+        Find or create a L{Bucket} corresponding to the provided parameters.
+
+        Any parameters are passed on to L{getBucketKey}, from them it
+        decides which bucket you get.
+
+        @returntype: L{Bucket}
+        """
+        if (self.sweepInterval is not None) and (
+            (time() - self.lastSweep) > self.sweepInterval
+        ):
+            self.sweep()
+
+        if self.parentFilter:
+            parentBucket = self.parentFilter.getBucketFor(self, *a, **kw)
+        else:
+            parentBucket = None
+
+        key = self.getBucketKey(*a, **kw)
+        bucket = self.buckets.get(key)
+        if bucket is None:
+            bucket = self.bucketFactory(parentBucket)
+            self.buckets[key] = bucket
+        return bucket
+
+    def getBucketKey(self, *a, **kw):
+        """
+        Construct a key based on the input parameters to choose a L{Bucket}.
+
+        The default implementation returns the same key for all
+        arguments. Override this method to provide L{Bucket} selection.
+
+        @returns: Something to be used as a key in the bucket cache.
+        """
+        return None
+
+    def sweep(self):
+        """
+        Remove empty buckets.
+        """
+        for key, bucket in self.buckets.items():
+            bucket_is_empty = bucket.drip()
+            if (bucket._refcount == 0) and bucket_is_empty:
+                del self.buckets[key]
+
+        self.lastSweep = time()
+
+
+class FilterByHost(HierarchicalBucketFilter):
+    """
+    A Hierarchical Bucket filter with a L{Bucket} for each host.
+    """
+
+    sweepInterval = 60 * 20
+
+    def getBucketKey(self, transport):
+        return transport.getPeer()[1]
+
+
+class FilterByServer(HierarchicalBucketFilter):
+    """
+    A Hierarchical Bucket filter with a L{Bucket} for each service.
+    """
+
+    sweepInterval = None
+
+    def getBucketKey(self, transport):
+        return transport.getHost()[2]
+
+
+class ShapedConsumer(pcp.ProducerConsumerProxy):
+    """
+    Wraps a C{Consumer} and shapes the rate at which it receives data.
+    """
+
+    # Providing a Pull interface means I don't have to try to schedule
+    # traffic with callLaters.
+    iAmStreaming = False
+
+    def __init__(self, consumer, bucket):
+        pcp.ProducerConsumerProxy.__init__(self, consumer)
+        self.bucket = bucket
+        self.bucket._refcount += 1
+
+    def _writeSomeData(self, data):
+        # In practice, this actually results in obscene amounts of
+        # overhead, as a result of generating lots and lots of packets
+        # with twelve-byte payloads.  We may need to do a version of
+        # this with scheduled writes after all.
+        amount = self.bucket.add(len(data))
+        return pcp.ProducerConsumerProxy._writeSomeData(self, data[:amount])
+
+    def stopProducing(self):
+        pcp.ProducerConsumerProxy.stopProducing(self)
+        self.bucket._refcount -= 1
+
+
+class ShapedTransport(ShapedConsumer):
+    """
+    Wraps a C{Transport} and shapes the rate at which it receives data.
+
+    This is a L{ShapedConsumer} with a little bit of magic to provide for
+    the case where the consumer it wraps is also a C{Transport} and people
+    will be attempting to access attributes this does not proxy as a
+    C{Consumer} (e.g. C{loseConnection}).
+    """
+
+    # Ugh.  We only wanted to filter IConsumer, not ITransport.
+
+    iAmStreaming = False
+
+    def __getattr__(self, name):
+        # Because people will be doing things like .getPeer and
+        # .loseConnection on me.
+        return getattr(self.consumer, name)
+
+
+class ShapedProtocolFactory:
+    """
+    Dispense C{Protocols} with traffic shaping on their transports.
+
+    Usage::
+
+        myserver = SomeFactory()
+        myserver.protocol = ShapedProtocolFactory(myserver.protocol,
+                                                  bucketFilter)
+
+    Where C{SomeServerFactory} is a L{twisted.internet.protocol.Factory}, and
+    C{bucketFilter} is an instance of L{HierarchicalBucketFilter}.
+    """
+
+    def __init__(self, protoClass, bucketFilter):
+        """
+        Tell me what to wrap and where to get buckets.
+
+        @param protoClass: The class of C{Protocol} this will generate
+          wrapped instances of.
+        @type protoClass: L{Protocol<twisted.internet.interfaces.IProtocol>}
+          class
+        @param bucketFilter: The filter which will determine how
+          traffic is shaped.
+        @type bucketFilter: L{HierarchicalBucketFilter}.
+        """
+        # More precisely, protoClass can be any callable that will return
+        # instances of something that implements IProtocol.
+        self.protocol = protoClass
+        self.bucketFilter = bucketFilter
+
+    def __call__(self, *a, **kw):
+        """
+        Make a C{Protocol} instance with a shaped transport.
+
+        Any parameters will be passed on to the protocol's initializer.
+
+        @returns: A C{Protocol} instance with a L{ShapedTransport}.
+        """
+        proto = self.protocol(*a, **kw)
+        origMakeConnection = proto.makeConnection
+
+        def makeConnection(transport):
+            bucket = self.bucketFilter.getBucketFor(transport)
+            shapedTransport = ShapedTransport(transport, bucket)
+            return origMakeConnection(shapedTransport)
+
+        proto.makeConnection = makeConnection
+        return proto

backend/lib/python3.12/site-packages/twisted/protocols/ident.py

@@ -0,0 +1,253 @@
+# -*- test-case-name: twisted.test.test_ident -*-
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""
+Ident protocol implementation.
+"""
+
+import struct
+
+from twisted.internet import defer
+from twisted.protocols import basic
+from twisted.python import failure, log
+
+_MIN_PORT = 1
+_MAX_PORT = 2**16 - 1
+
+
+class IdentError(Exception):
+    """
+    Can't determine connection owner; reason unknown.
+    """
+
+    identDescription = "UNKNOWN-ERROR"
+
+    def __str__(self) -> str:
+        return self.identDescription
+
+
+class NoUser(IdentError):
+    """
+    The connection specified by the port pair is not currently in use or
+    currently not owned by an identifiable entity.
+    """
+
+    identDescription = "NO-USER"
+
+
+class InvalidPort(IdentError):
+    """
+    Either the local or foreign port was improperly specified. This should
+    be returned if either or both of the port ids were out of range (TCP
+    port numbers are from 1-65535), negative integers, reals or in any
+    fashion not recognized as a non-negative integer.
+    """
+
+    identDescription = "INVALID-PORT"
+
+
+class HiddenUser(IdentError):
+    """
+    The server was able to identify the user of this port, but the
+    information was not returned at the request of the user.
+    """
+
+    identDescription = "HIDDEN-USER"
+
+
+class IdentServer(basic.LineOnlyReceiver):
+    """
+    The Identification Protocol (a.k.a., "ident", a.k.a., "the Ident
+    Protocol") provides a means to determine the identity of a user of a
+    particular TCP connection. Given a TCP port number pair, it returns a
+    character string which identifies the owner of that connection on the
+    server's system.
+
+    Server authors should subclass this class and override the lookup method.
+    The default implementation returns an UNKNOWN-ERROR response for every
+    query.
+    """
+
+    def lineReceived(self, line):
+        parts = line.split(",")
+        if len(parts) != 2:
+            self.invalidQuery()
+        else:
+            try:
+                portOnServer, portOnClient = map(int, parts)
+            except ValueError:
+                self.invalidQuery()
+            else:
+                if (
+                    _MIN_PORT <= portOnServer <= _MAX_PORT
+                    and _MIN_PORT <= portOnClient <= _MAX_PORT
+                ):
+                    self.validQuery(portOnServer, portOnClient)
+                else:
+                    self._ebLookup(
+                        failure.Failure(InvalidPort()), portOnServer, portOnClient
+                    )
+
+    def invalidQuery(self):
+        self.transport.loseConnection()
+
+    def validQuery(self, portOnServer, portOnClient):
+        """
+        Called when a valid query is received to look up and deliver the
+        response.
+
+        @param portOnServer: The server port from the query.
+        @param portOnClient: The client port from the query.
+        """
+        serverAddr = self.transport.getHost().host, portOnServer
+        clientAddr = self.transport.getPeer().host, portOnClient
+        defer.maybeDeferred(self.lookup, serverAddr, clientAddr).addCallback(
+            self._cbLookup, portOnServer, portOnClient
+        ).addErrback(self._ebLookup, portOnServer, portOnClient)
+
+    def _cbLookup(self, result, sport, cport):
+        (sysName, userId) = result
+        self.sendLine("%d, %d : USERID : %s : %s" % (sport, cport, sysName, userId))
+
+    def _ebLookup(self, failure, sport, cport):
+        if failure.check(IdentError):
+            self.sendLine("%d, %d : ERROR : %s" % (sport, cport, failure.value))
+        else:
+            log.err(failure)
+            self.sendLine(
+                "%d, %d : ERROR : %s" % (sport, cport, IdentError(failure.value))
+            )
+
+    def lookup(self, serverAddress, clientAddress):
+        """
+        Lookup user information about the specified address pair.
+
+        Return value should be a two-tuple of system name and username.
+        Acceptable values for the system name may be found online at::
+
+            U{http://www.iana.org/assignments/operating-system-names}
+
+        This method may also raise any IdentError subclass (or IdentError
+        itself) to indicate user information will not be provided for the
+        given query.
+
+        A Deferred may also be returned.
+
+        @param serverAddress: A two-tuple representing the server endpoint
+        of the address being queried.  The first element is a string holding
+        a dotted-quad IP address.  The second element is an integer
+        representing the port.
+
+        @param clientAddress: Like I{serverAddress}, but represents the
+        client endpoint of the address being queried.
+        """
+        raise IdentError()
+
+
+class ProcServerMixin:
+    """Implements lookup() to grab entries for responses from /proc/net/tcp"""
+
+    SYSTEM_NAME = "LINUX"
+
+    try:
+        from pwd import getpwuid  # type:ignore[misc]
+
+        def getUsername(self, uid, getpwuid=getpwuid):
+            return getpwuid(uid)[0]
+
+        del getpwuid
+    except ImportError:
+
+        def getUsername(self, uid, getpwuid=None):
+            raise IdentError()
+
+    def entries(self):
+        with open("/proc/net/tcp") as f:
+            f.readline()
+            for L in f:
+                yield L.strip()
+
+    def dottedQuadFromHexString(self, hexstr):
+        return ".".join(
+            map(str, struct.unpack("4B", struct.pack("=L", int(hexstr, 16))))
+        )
+
+    def unpackAddress(self, packed):
+        addr, port = packed.split(":")
+        addr = self.dottedQuadFromHexString(addr)
+        port = int(port, 16)
+        return addr, port
+
+    def parseLine(self, line):
+        parts = line.strip().split()
+        localAddr, localPort = self.unpackAddress(parts[1])
+        remoteAddr, remotePort = self.unpackAddress(parts[2])
+        uid = int(parts[7])
+        return (localAddr, localPort), (remoteAddr, remotePort), uid
+
+    def lookup(self, serverAddress, clientAddress):
+        for ent in self.entries():
+            localAddr, remoteAddr, uid = self.parseLine(ent)
+            if remoteAddr == clientAddress and localAddr[1] == serverAddress[1]:
+                return (self.SYSTEM_NAME, self.getUsername(uid))
+
+        raise NoUser()
+
+
+class IdentClient(basic.LineOnlyReceiver):
+    errorTypes = (IdentError, NoUser, InvalidPort, HiddenUser)
+
+    def __init__(self):
+        self.queries = []
+
+    def lookup(self, portOnServer, portOnClient):
+        """
+        Lookup user information about the specified address pair.
+        """
+        self.queries.append((defer.Deferred(), portOnServer, portOnClient))
+        if len(self.queries) > 1:
+            return self.queries[-1][0]
+
+        self.sendLine("%d, %d" % (portOnServer, portOnClient))
+        return self.queries[-1][0]
+
+    def lineReceived(self, line):
+        if not self.queries:
+            log.msg(f"Unexpected server response: {line!r}")
+        else:
+            d, _, _ = self.queries.pop(0)
+            self.parseResponse(d, line)
+            if self.queries:
+                self.sendLine("%d, %d" % (self.queries[0][1], self.queries[0][2]))
+
+    def connectionLost(self, reason):
+        for q in self.queries:
+            q[0].errback(IdentError(reason))
+        self.queries = []
+
+    def parseResponse(self, deferred, line):
+        parts = line.split(":", 2)
+        if len(parts) != 3:
+            deferred.errback(IdentError(line))
+        else:
+            ports, type, addInfo = map(str.strip, parts)
+            if type == "ERROR":
+                for et in self.errorTypes:
+                    if et.identDescription == addInfo:
+                        deferred.errback(et(line))
+                        return
+                deferred.errback(IdentError(line))
+            else:
+                deferred.callback((type, addInfo))
+
+
+__all__ = [
+    "IdentError",
+    "NoUser",
+    "InvalidPort",
+    "HiddenUser",
+    "IdentServer",
+    "IdentClient",
+    "ProcServerMixin",
+]

backend/lib/python3.12/site-packages/twisted/protocols/loopback.py

@@ -0,0 +1,387 @@
+# -*- test-case-name: twisted.test.test_loopback -*-
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""
+Testing support for protocols -- loopback between client and server.
+"""
+
+
+# system imports
+import tempfile
+
+from zope.interface import implementer
+
+from twisted.internet import defer, interfaces, main, protocol
+from twisted.internet.interfaces import IAddress
+from twisted.internet.task import deferLater
+
+# Twisted Imports
+from twisted.protocols import policies
+from twisted.python import failure
+
+
+class _LoopbackQueue:
+    """
+    Trivial wrapper around a list to give it an interface like a queue, which
+    the addition of also sending notifications by way of a Deferred whenever
+    the list has something added to it.
+    """
+
+    _notificationDeferred = None
+    disconnect = False
+
+    def __init__(self):
+        self._queue = []
+
+    def put(self, v):
+        self._queue.append(v)
+        if self._notificationDeferred is not None:
+            d, self._notificationDeferred = self._notificationDeferred, None
+            d.callback(None)
+
+    def __nonzero__(self):
+        return bool(self._queue)
+
+    __bool__ = __nonzero__
+
+    def get(self):
+        return self._queue.pop(0)
+
+
+@implementer(IAddress)
+class _LoopbackAddress:
+    pass
+
+
+@implementer(interfaces.ITransport, interfaces.IConsumer)
+class _LoopbackTransport:
+    disconnecting = False
+    producer = None
+
+    # ITransport
+    def __init__(self, q):
+        self.q = q
+
+    def write(self, data):
+        if not isinstance(data, bytes):
+            raise TypeError("Can only write bytes to ITransport")
+        self.q.put(data)
+
+    def writeSequence(self, iovec):
+        self.q.put(b"".join(iovec))
+
+    def loseConnection(self):
+        self.q.disconnect = True
+        self.q.put(None)
+
+    def abortConnection(self):
+        """
+        Abort the connection. Same as L{loseConnection}.
+        """
+        self.loseConnection()
+
+    def getPeer(self):
+        return _LoopbackAddress()
+
+    def getHost(self):
+        return _LoopbackAddress()
+
+    # IConsumer
+    def registerProducer(self, producer, streaming):
+        assert self.producer is None
+        self.producer = producer
+        self.streamingProducer = streaming
+        self._pollProducer()
+
+    def unregisterProducer(self):
+        assert self.producer is not None
+        self.producer = None
+
+    def _pollProducer(self):
+        if self.producer is not None and not self.streamingProducer:
+            self.producer.resumeProducing()
+
+
+def identityPumpPolicy(queue, target):
+    """
+    L{identityPumpPolicy} is a policy which delivers each chunk of data written
+    to the given queue as-is to the target.
+
+    This isn't a particularly realistic policy.
+
+    @see: L{loopbackAsync}
+    """
+    while queue:
+        bytes = queue.get()
+        if bytes is None:
+            break
+        target.dataReceived(bytes)
+
+
+def collapsingPumpPolicy(queue, target):
+    """
+    L{collapsingPumpPolicy} is a policy which collapses all outstanding chunks
+    into a single string and delivers it to the target.
+
+    @see: L{loopbackAsync}
+    """
+    bytes = []
+    while queue:
+        chunk = queue.get()
+        if chunk is None:
+            break
+        bytes.append(chunk)
+    if bytes:
+        target.dataReceived(b"".join(bytes))
+
+
+def loopbackAsync(server, client, pumpPolicy=identityPumpPolicy):
+    """
+    Establish a connection between C{server} and C{client} then transfer data
+    between them until the connection is closed. This is often useful for
+    testing a protocol.
+
+    @param server: The protocol instance representing the server-side of this
+        connection.
+
+    @param client: The protocol instance representing the client-side of this
+        connection.
+
+    @param pumpPolicy: When either C{server} or C{client} writes to its
+        transport, the string passed in is added to a queue of data for the
+        other protocol.  Eventually, C{pumpPolicy} will be called with one such
+        queue and the corresponding protocol object.  The pump policy callable
+        is responsible for emptying the queue and passing the strings it
+        contains to the given protocol's C{dataReceived} method.  The signature
+        of C{pumpPolicy} is C{(queue, protocol)}.  C{queue} is an object with a
+        C{get} method which will return the next string written to the
+        transport, or L{None} if the transport has been disconnected, and which
+        evaluates to C{True} if and only if there are more items to be
+        retrieved via C{get}.
+
+    @return: A L{Deferred} which fires when the connection has been closed and
+        both sides have received notification of this.
+    """
+    serverToClient = _LoopbackQueue()
+    clientToServer = _LoopbackQueue()
+
+    server.makeConnection(_LoopbackTransport(serverToClient))
+    client.makeConnection(_LoopbackTransport(clientToServer))
+
+    return _loopbackAsyncBody(
+        server, serverToClient, client, clientToServer, pumpPolicy
+    )
+
+
+def _loopbackAsyncBody(server, serverToClient, client, clientToServer, pumpPolicy):
+    """
+    Transfer bytes from the output queue of each protocol to the input of the other.
+
+    @param server: The protocol instance representing the server-side of this
+    connection.
+
+    @param serverToClient: The L{_LoopbackQueue} holding the server's output.
+
+    @param client: The protocol instance representing the client-side of this
+    connection.
+
+    @param clientToServer: The L{_LoopbackQueue} holding the client's output.
+
+    @param pumpPolicy: See L{loopbackAsync}.
+
+    @return: A L{Deferred} which fires when the connection has been closed and
+        both sides have received notification of this.
+    """
+
+    def pump(source, q, target):
+        sent = False
+        if q:
+            pumpPolicy(q, target)
+            sent = True
+        if sent and not q:
+            # A write buffer has now been emptied.  Give any producer on that
+            # side an opportunity to produce more data.
+            source.transport._pollProducer()
+
+        return sent
+
+    while 1:
+        disconnect = clientSent = serverSent = False
+
+        # Deliver the data which has been written.
+        serverSent = pump(server, serverToClient, client)
+        clientSent = pump(client, clientToServer, server)
+
+        if not clientSent and not serverSent:
+            # Neither side wrote any data.  Wait for some new data to be added
+            # before trying to do anything further.
+            d = defer.Deferred()
+            clientToServer._notificationDeferred = d
+            serverToClient._notificationDeferred = d
+            d.addCallback(
+                _loopbackAsyncContinue,
+                server,
+                serverToClient,
+                client,
+                clientToServer,
+                pumpPolicy,
+            )
+            return d
+        if serverToClient.disconnect:
+            # The server wants to drop the connection.  Flush any remaining
+            # data it has.
+            disconnect = True
+            pump(server, serverToClient, client)
+        elif clientToServer.disconnect:
+            # The client wants to drop the connection.  Flush any remaining
+            # data it has.
+            disconnect = True
+            pump(client, clientToServer, server)
+        if disconnect:
+            # Someone wanted to disconnect, so okay, the connection is gone.
+            server.connectionLost(failure.Failure(main.CONNECTION_DONE))
+            client.connectionLost(failure.Failure(main.CONNECTION_DONE))
+            return defer.succeed(None)
+
+
+def _loopbackAsyncContinue(
+    ignored, server, serverToClient, client, clientToServer, pumpPolicy
+):
+    # Clear the Deferred from each message queue, since it has already fired
+    # and cannot be used again.
+    clientToServer._notificationDeferred = None
+    serverToClient._notificationDeferred = None
+
+    # Schedule some more byte-pushing to happen.  This isn't done
+    # synchronously because no actual transport can re-enter dataReceived as
+    # a result of calling write, and doing this synchronously could result
+    # in that.
+    from twisted.internet import reactor
+
+    return deferLater(
+        reactor,
+        0,
+        _loopbackAsyncBody,
+        server,
+        serverToClient,
+        client,
+        clientToServer,
+        pumpPolicy,
+    )
+
+
+@implementer(interfaces.ITransport, interfaces.IConsumer)
+class LoopbackRelay:
+    buffer = b""
+    shouldLose = 0
+    disconnecting = 0
+    producer = None
+
+    def __init__(self, target, logFile=None):
+        self.target = target
+        self.logFile = logFile
+
+    def write(self, data):
+        self.buffer = self.buffer + data
+        if self.logFile:
+            self.logFile.write("loopback writing %s\n" % repr(data))
+
+    def writeSequence(self, iovec):
+        self.write(b"".join(iovec))
+
+    def clearBuffer(self):
+        if self.shouldLose == -1:
+            return
+
+        if self.producer:
+            self.producer.resumeProducing()
+        if self.buffer:
+            if self.logFile:
+                self.logFile.write("loopback receiving %s\n" % repr(self.buffer))
+            buffer = self.buffer
+            self.buffer = b""
+            self.target.dataReceived(buffer)
+        if self.shouldLose == 1:
+            self.shouldLose = -1
+            self.target.connectionLost(failure.Failure(main.CONNECTION_DONE))
+
+    def loseConnection(self):
+        if self.shouldLose != -1:
+            self.shouldLose = 1
+
+    def getHost(self):
+        return "loopback"
+
+    def getPeer(self):
+        return "loopback"
+
+    def registerProducer(self, producer, streaming):
+        self.producer = producer
+
+    def unregisterProducer(self):
+        self.producer = None
+
+    def logPrefix(self):
+        return f"Loopback({self.target.__class__.__name__!r})"
+
+
+class LoopbackClientFactory(protocol.ClientFactory):
+    def __init__(self, protocol):
+        self.disconnected = 0
+        self.deferred = defer.Deferred()
+        self.protocol = protocol
+
+    def buildProtocol(self, addr):
+        return self.protocol
+
+    def clientConnectionLost(self, connector, reason):
+        self.disconnected = 1
+        self.deferred.callback(None)
+
+
+class _FireOnClose(policies.ProtocolWrapper):
+    def __init__(self, protocol, factory):
+        policies.ProtocolWrapper.__init__(self, protocol, factory)
+        self.deferred = defer.Deferred()
+
+    def connectionLost(self, reason):
+        policies.ProtocolWrapper.connectionLost(self, reason)
+        self.deferred.callback(None)
+
+
+def loopbackTCP(server, client, port=0, noisy=True):
+    """Run session between server and client protocol instances over TCP."""
+    from twisted.internet import reactor
+
+    f = policies.WrappingFactory(protocol.Factory())
+    serverWrapper = _FireOnClose(f, server)
+    f.noisy = noisy
+    f.buildProtocol = lambda addr: serverWrapper
+    serverPort = reactor.listenTCP(port, f, interface="127.0.0.1")
+    clientF = LoopbackClientFactory(client)
+    clientF.noisy = noisy
+    reactor.connectTCP("127.0.0.1", serverPort.getHost().port, clientF)
+    d = clientF.deferred
+    d.addCallback(lambda x: serverWrapper.deferred)
+    d.addCallback(lambda x: serverPort.stopListening())
+    return d
+
+
+def loopbackUNIX(server, client, noisy=True):
+    """Run session between server and client protocol instances over UNIX socket."""
+    path = tempfile.mktemp()
+    from twisted.internet import reactor
+
+    f = policies.WrappingFactory(protocol.Factory())
+    serverWrapper = _FireOnClose(f, server)
+    f.noisy = noisy
+    f.buildProtocol = lambda addr: serverWrapper
+    serverPort = reactor.listenUNIX(path, f)
+    clientF = LoopbackClientFactory(client)
+    clientF.noisy = noisy
+    reactor.connectUNIX(path, clientF)
+    d = clientF.deferred
+    d.addCallback(lambda x: serverWrapper.deferred)
+    d.addCallback(lambda x: serverPort.stopListening())
+    return d

backend/lib/python3.12/site-packages/twisted/protocols/memcache.py

@@ -0,0 +1,733 @@
+# -*- test-case-name: twisted.test.test_memcache -*-
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""
+Memcache client protocol. Memcached is a caching server, storing data in the
+form of pairs key/value, and memcache is the protocol to talk with it.
+
+To connect to a server, create a factory for L{MemCacheProtocol}::
+
+    from twisted.internet import reactor, protocol
+    from twisted.protocols.memcache import MemCacheProtocol, DEFAULT_PORT
+    d = protocol.ClientCreator(reactor, MemCacheProtocol
+        ).connectTCP("localhost", DEFAULT_PORT)
+    def doSomething(proto):
+        # Here you call the memcache operations
+        return proto.set("mykey", "a lot of data")
+    d.addCallback(doSomething)
+    reactor.run()
+
+All the operations of the memcache protocol are present, but
+L{MemCacheProtocol.set} and L{MemCacheProtocol.get} are the more important.
+
+See U{http://code.sixapart.com/svn/memcached/trunk/server/doc/protocol.txt} for
+more information about the protocol.
+"""
+
+
+from collections import deque
+
+from twisted.internet.defer import Deferred, TimeoutError, fail
+from twisted.protocols.basic import LineReceiver
+from twisted.protocols.policies import TimeoutMixin
+from twisted.python import log
+from twisted.python.compat import nativeString, networkString
+
+DEFAULT_PORT = 11211
+
+
+class NoSuchCommand(Exception):
+    """
+    Exception raised when a non existent command is called.
+    """
+
+
+class ClientError(Exception):
+    """
+    Error caused by an invalid client call.
+    """
+
+
+class ServerError(Exception):
+    """
+    Problem happening on the server.
+    """
+
+
+class Command:
+    """
+    Wrap a client action into an object, that holds the values used in the
+    protocol.
+
+    @ivar _deferred: the L{Deferred} object that will be fired when the result
+        arrives.
+    @type _deferred: L{Deferred}
+
+    @ivar command: name of the command sent to the server.
+    @type command: L{bytes}
+    """
+
+    def __init__(self, command, **kwargs):
+        """
+        Create a command.
+
+        @param command: the name of the command.
+        @type command: L{bytes}
+
+        @param kwargs: this values will be stored as attributes of the object
+            for future use
+        """
+        self.command = command
+        self._deferred = Deferred()
+        for k, v in kwargs.items():
+            setattr(self, k, v)
+
+    def success(self, value):
+        """
+        Shortcut method to fire the underlying deferred.
+        """
+        self._deferred.callback(value)
+
+    def fail(self, error):
+        """
+        Make the underlying deferred fails.
+        """
+        self._deferred.errback(error)
+
+
+class MemCacheProtocol(LineReceiver, TimeoutMixin):
+    """
+    MemCache protocol: connect to a memcached server to store/retrieve values.
+
+    @ivar persistentTimeOut: the timeout period used to wait for a response.
+    @type persistentTimeOut: L{int}
+
+    @ivar _current: current list of requests waiting for an answer from the
+        server.
+    @type _current: L{deque} of L{Command}
+
+    @ivar _lenExpected: amount of data expected in raw mode, when reading for
+        a value.
+    @type _lenExpected: L{int}
+
+    @ivar _getBuffer: current buffer of data, used to store temporary data
+        when reading in raw mode.
+    @type _getBuffer: L{list}
+
+    @ivar _bufferLength: the total amount of bytes in C{_getBuffer}.
+    @type _bufferLength: L{int}
+
+    @ivar _disconnected: indicate if the connectionLost has been called or not.
+    @type _disconnected: L{bool}
+    """
+
+    MAX_KEY_LENGTH = 250
+    _disconnected = False
+
+    def __init__(self, timeOut=60):
+        """
+        Create the protocol.
+
+        @param timeOut: the timeout to wait before detecting that the
+            connection is dead and close it. It's expressed in seconds.
+        @type timeOut: L{int}
+        """
+        self._current = deque()
+        self._lenExpected = None
+        self._getBuffer = None
+        self._bufferLength = None
+        self.persistentTimeOut = self.timeOut = timeOut
+
+    def _cancelCommands(self, reason):
+        """
+        Cancel all the outstanding commands, making them fail with C{reason}.
+        """
+        while self._current:
+            cmd = self._current.popleft()
+            cmd.fail(reason)
+
+    def timeoutConnection(self):
+        """
+        Close the connection in case of timeout.
+        """
+        self._cancelCommands(TimeoutError("Connection timeout"))
+        self.transport.loseConnection()
+
+    def connectionLost(self, reason):
+        """
+        Cause any outstanding commands to fail.
+        """
+        self._disconnected = True
+        self._cancelCommands(reason)
+        LineReceiver.connectionLost(self, reason)
+
+    def sendLine(self, line):
+        """
+        Override sendLine to add a timeout to response.
+        """
+        if not self._current:
+            self.setTimeout(self.persistentTimeOut)
+        LineReceiver.sendLine(self, line)
+
+    def rawDataReceived(self, data):
+        """
+        Collect data for a get.
+        """
+        self.resetTimeout()
+        self._getBuffer.append(data)
+        self._bufferLength += len(data)
+        if self._bufferLength >= self._lenExpected + 2:
+            data = b"".join(self._getBuffer)
+            buf = data[: self._lenExpected]
+            rem = data[self._lenExpected + 2 :]
+            val = buf
+            self._lenExpected = None
+            self._getBuffer = None
+            self._bufferLength = None
+            cmd = self._current[0]
+            if cmd.multiple:
+                flags, cas = cmd.values[cmd.currentKey]
+                cmd.values[cmd.currentKey] = (flags, cas, val)
+            else:
+                cmd.value = val
+            self.setLineMode(rem)
+
+    def cmd_STORED(self):
+        """
+        Manage a success response to a set operation.
+        """
+        self._current.popleft().success(True)
+
+    def cmd_NOT_STORED(self):
+        """
+        Manage a specific 'not stored' response to a set operation: this is not
+        an error, but some condition wasn't met.
+        """
+        self._current.popleft().success(False)
+
+    def cmd_END(self):
+        """
+        This the end token to a get or a stat operation.
+        """
+        cmd = self._current.popleft()
+        if cmd.command == b"get":
+            if cmd.multiple:
+                values = {key: val[::2] for key, val in cmd.values.items()}
+                cmd.success(values)
+            else:
+                cmd.success((cmd.flags, cmd.value))
+        elif cmd.command == b"gets":
+            if cmd.multiple:
+                cmd.success(cmd.values)
+            else:
+                cmd.success((cmd.flags, cmd.cas, cmd.value))
+        elif cmd.command == b"stats":
+            cmd.success(cmd.values)
+        else:
+            raise RuntimeError(
+                "Unexpected END response to {} command".format(
+                    nativeString(cmd.command)
+                )
+            )
+
+    def cmd_NOT_FOUND(self):
+        """
+        Manage error response for incr/decr/delete.
+        """
+        self._current.popleft().success(False)
+
+    def cmd_VALUE(self, line):
+        """
+        Prepare the reading a value after a get.
+        """
+        cmd = self._current[0]
+        if cmd.command == b"get":
+            key, flags, length = line.split()
+            cas = b""
+        else:
+            key, flags, length, cas = line.split()
+        self._lenExpected = int(length)
+        self._getBuffer = []
+        self._bufferLength = 0
+        if cmd.multiple:
+            if key not in cmd.keys:
+                raise RuntimeError("Unexpected commands answer.")
+            cmd.currentKey = key
+            cmd.values[key] = [int(flags), cas]
+        else:
+            if cmd.key != key:
+                raise RuntimeError("Unexpected commands answer.")
+            cmd.flags = int(flags)
+            cmd.cas = cas
+        self.setRawMode()
+
+    def cmd_STAT(self, line):
+        """
+        Reception of one stat line.
+        """
+        cmd = self._current[0]
+        key, val = line.split(b" ", 1)
+        cmd.values[key] = val
+
+    def cmd_VERSION(self, versionData):
+        """
+        Read version token.
+        """
+        self._current.popleft().success(versionData)
+
+    def cmd_ERROR(self):
+        """
+        A non-existent command has been sent.
+        """
+        log.err("Non-existent command sent.")
+        cmd = self._current.popleft()
+        cmd.fail(NoSuchCommand())
+
+    def cmd_CLIENT_ERROR(self, errText):
+        """
+        An invalid input as been sent.
+        """
+        errText = repr(errText)
+        log.err("Invalid input: " + errText)
+        cmd = self._current.popleft()
+        cmd.fail(ClientError(errText))
+
+    def cmd_SERVER_ERROR(self, errText):
+        """
+        An error has happened server-side.
+        """
+        errText = repr(errText)
+        log.err("Server error: " + errText)
+        cmd = self._current.popleft()
+        cmd.fail(ServerError(errText))
+
+    def cmd_DELETED(self):
+        """
+        A delete command has completed successfully.
+        """
+        self._current.popleft().success(True)
+
+    def cmd_OK(self):
+        """
+        The last command has been completed.
+        """
+        self._current.popleft().success(True)
+
+    def cmd_EXISTS(self):
+        """
+        A C{checkAndSet} update has failed.
+        """
+        self._current.popleft().success(False)
+
+    def lineReceived(self, line):
+        """
+        Receive line commands from the server.
+        """
+        self.resetTimeout()
+        token = line.split(b" ", 1)[0]
+        # First manage standard commands without space
+        cmd = getattr(self, "cmd_" + nativeString(token), None)
+        if cmd is not None:
+            args = line.split(b" ", 1)[1:]
+            if args:
+                cmd(args[0])
+            else:
+                cmd()
+        else:
+            # Then manage commands with space in it
+            line = line.replace(b" ", b"_")
+            cmd = getattr(self, "cmd_" + nativeString(line), None)
+            if cmd is not None:
+                cmd()
+            else:
+                # Increment/Decrement response
+                cmd = self._current.popleft()
+                val = int(line)
+                cmd.success(val)
+        if not self._current:
+            # No pending request, remove timeout
+            self.setTimeout(None)
+
+    def increment(self, key, val=1):
+        """
+        Increment the value of C{key} by given value (default to 1).
+        C{key} must be consistent with an int. Return the new value.
+
+        @param key: the key to modify.
+        @type key: L{bytes}
+
+        @param val: the value to increment.
+        @type val: L{int}
+
+        @return: a deferred with will be called back with the new value
+            associated with the key (after the increment).
+        @rtype: L{Deferred}
+        """
+        return self._incrdecr(b"incr", key, val)
+
+    def decrement(self, key, val=1):
+        """
+        Decrement the value of C{key} by given value (default to 1).
+        C{key} must be consistent with an int. Return the new value, coerced to
+        0 if negative.
+
+        @param key: the key to modify.
+        @type key: L{bytes}
+
+        @param val: the value to decrement.
+        @type val: L{int}
+
+        @return: a deferred with will be called back with the new value
+            associated with the key (after the decrement).
+        @rtype: L{Deferred}
+        """
+        return self._incrdecr(b"decr", key, val)
+
+    def _incrdecr(self, cmd, key, val):
+        """
+        Internal wrapper for incr/decr.
+        """
+        if self._disconnected:
+            return fail(RuntimeError("not connected"))
+        if not isinstance(key, bytes):
+            return fail(
+                ClientError(f"Invalid type for key: {type(key)}, expecting bytes")
+            )
+        if len(key) > self.MAX_KEY_LENGTH:
+            return fail(ClientError("Key too long"))
+        fullcmd = b" ".join([cmd, key, b"%d" % (int(val),)])
+        self.sendLine(fullcmd)
+        cmdObj = Command(cmd, key=key)
+        self._current.append(cmdObj)
+        return cmdObj._deferred
+
+    def replace(self, key, val, flags=0, expireTime=0):
+        """
+        Replace the given C{key}. It must already exist in the server.
+
+        @param key: the key to replace.
+        @type key: L{bytes}
+
+        @param val: the new value associated with the key.
+        @type val: L{bytes}
+
+        @param flags: the flags to store with the key.
+        @type flags: L{int}
+
+        @param expireTime: if different from 0, the relative time in seconds
+            when the key will be deleted from the store.
+        @type expireTime: L{int}
+
+        @return: a deferred that will fire with C{True} if the operation has
+            succeeded, and C{False} with the key didn't previously exist.
+        @rtype: L{Deferred}
+        """
+        return self._set(b"replace", key, val, flags, expireTime, b"")
+
+    def add(self, key, val, flags=0, expireTime=0):
+        """
+        Add the given C{key}. It must not exist in the server.
+
+        @param key: the key to add.
+        @type key: L{bytes}
+
+        @param val: the value associated with the key.
+        @type val: L{bytes}
+
+        @param flags: the flags to store with the key.
+        @type flags: L{int}
+
+        @param expireTime: if different from 0, the relative time in seconds
+            when the key will be deleted from the store.
+        @type expireTime: L{int}
+
+        @return: a deferred that will fire with C{True} if the operation has
+            succeeded, and C{False} with the key already exists.
+        @rtype: L{Deferred}
+        """
+        return self._set(b"add", key, val, flags, expireTime, b"")
+
+    def set(self, key, val, flags=0, expireTime=0):
+        """
+        Set the given C{key}.
+
+        @param key: the key to set.
+        @type key: L{bytes}
+
+        @param val: the value associated with the key.
+        @type val: L{bytes}
+
+        @param flags: the flags to store with the key.
+        @type flags: L{int}
+
+        @param expireTime: if different from 0, the relative time in seconds
+            when the key will be deleted from the store.
+        @type expireTime: L{int}
+
+        @return: a deferred that will fire with C{True} if the operation has
+            succeeded.
+        @rtype: L{Deferred}
+        """
+        return self._set(b"set", key, val, flags, expireTime, b"")
+
+    def checkAndSet(self, key, val, cas, flags=0, expireTime=0):
+        """
+        Change the content of C{key} only if the C{cas} value matches the
+        current one associated with the key. Use this to store a value which
+        hasn't been modified since last time you fetched it.
+
+        @param key: The key to set.
+        @type key: L{bytes}
+
+        @param val: The value associated with the key.
+        @type val: L{bytes}
+
+        @param cas: Unique 64-bit value returned by previous call of C{get}.
+        @type cas: L{bytes}
+
+        @param flags: The flags to store with the key.
+        @type flags: L{int}
+
+        @param expireTime: If different from 0, the relative time in seconds
+            when the key will be deleted from the store.
+        @type expireTime: L{int}
+
+        @return: A deferred that will fire with C{True} if the operation has
+            succeeded, C{False} otherwise.
+        @rtype: L{Deferred}
+        """
+        return self._set(b"cas", key, val, flags, expireTime, cas)
+
+    def _set(self, cmd, key, val, flags, expireTime, cas):
+        """
+        Internal wrapper for setting values.
+        """
+        if self._disconnected:
+            return fail(RuntimeError("not connected"))
+        if not isinstance(key, bytes):
+            return fail(
+                ClientError(f"Invalid type for key: {type(key)}, expecting bytes")
+            )
+        if len(key) > self.MAX_KEY_LENGTH:
+            return fail(ClientError("Key too long"))
+        if not isinstance(val, bytes):
+            return fail(
+                ClientError(f"Invalid type for value: {type(val)}, expecting bytes")
+            )
+        if cas:
+            cas = b" " + cas
+        length = len(val)
+        fullcmd = (
+            b" ".join(
+                [cmd, key, networkString("%d %d %d" % (flags, expireTime, length))]
+            )
+            + cas
+        )
+        self.sendLine(fullcmd)
+        self.sendLine(val)
+        cmdObj = Command(cmd, key=key, flags=flags, length=length)
+        self._current.append(cmdObj)
+        return cmdObj._deferred
+
+    def append(self, key, val):
+        """
+        Append given data to the value of an existing key.
+
+        @param key: The key to modify.
+        @type key: L{bytes}
+
+        @param val: The value to append to the current value associated with
+            the key.
+        @type val: L{bytes}
+
+        @return: A deferred that will fire with C{True} if the operation has
+            succeeded, C{False} otherwise.
+        @rtype: L{Deferred}
+        """
+        # Even if flags and expTime values are ignored, we have to pass them
+        return self._set(b"append", key, val, 0, 0, b"")
+
+    def prepend(self, key, val):
+        """
+        Prepend given data to the value of an existing key.
+
+        @param key: The key to modify.
+        @type key: L{bytes}
+
+        @param val: The value to prepend to the current value associated with
+            the key.
+        @type val: L{bytes}
+
+        @return: A deferred that will fire with C{True} if the operation has
+            succeeded, C{False} otherwise.
+        @rtype: L{Deferred}
+        """
+        # Even if flags and expTime values are ignored, we have to pass them
+        return self._set(b"prepend", key, val, 0, 0, b"")
+
+    def get(self, key, withIdentifier=False):
+        """
+        Get the given C{key}. It doesn't support multiple keys. If
+        C{withIdentifier} is set to C{True}, the command issued is a C{gets},
+        that will return the current identifier associated with the value. This
+        identifier has to be used when issuing C{checkAndSet} update later,
+        using the corresponding method.
+
+        @param key: The key to retrieve.
+        @type key: L{bytes}
+
+        @param withIdentifier: If set to C{True}, retrieve the current
+            identifier along with the value and the flags.
+        @type withIdentifier: L{bool}
+
+        @return: A deferred that will fire with the tuple (flags, value) if
+            C{withIdentifier} is C{False}, or (flags, cas identifier, value)
+            if C{True}.  If the server indicates there is no value
+            associated with C{key}, the returned value will be L{None} and
+            the returned flags will be C{0}.
+        @rtype: L{Deferred}
+        """
+        return self._get([key], withIdentifier, False)
+
+    def getMultiple(self, keys, withIdentifier=False):
+        """
+        Get the given list of C{keys}.  If C{withIdentifier} is set to C{True},
+        the command issued is a C{gets}, that will return the identifiers
+        associated with each values. This identifier has to be used when
+        issuing C{checkAndSet} update later, using the corresponding method.
+
+        @param keys: The keys to retrieve.
+        @type keys: L{list} of L{bytes}
+
+        @param withIdentifier: If set to C{True}, retrieve the identifiers
+            along with the values and the flags.
+        @type withIdentifier: L{bool}
+
+        @return: A deferred that will fire with a dictionary with the elements
+            of C{keys} as keys and the tuples (flags, value) as values if
+            C{withIdentifier} is C{False}, or (flags, cas identifier, value) if
+            C{True}.  If the server indicates there is no value associated with
+            C{key}, the returned values will be L{None} and the returned flags
+            will be C{0}.
+        @rtype: L{Deferred}
+
+        @since: 9.0
+        """
+        return self._get(keys, withIdentifier, True)
+
+    def _get(self, keys, withIdentifier, multiple):
+        """
+        Helper method for C{get} and C{getMultiple}.
+        """
+        keys = list(keys)
+        if self._disconnected:
+            return fail(RuntimeError("not connected"))
+        for key in keys:
+            if not isinstance(key, bytes):
+                return fail(
+                    ClientError(f"Invalid type for key: {type(key)}, expecting bytes")
+                )
+            if len(key) > self.MAX_KEY_LENGTH:
+                return fail(ClientError("Key too long"))
+        if withIdentifier:
+            cmd = b"gets"
+        else:
+            cmd = b"get"
+        fullcmd = b" ".join([cmd] + keys)
+        self.sendLine(fullcmd)
+        if multiple:
+            values = {key: (0, b"", None) for key in keys}
+            cmdObj = Command(cmd, keys=keys, values=values, multiple=True)
+        else:
+            cmdObj = Command(
+                cmd, key=keys[0], value=None, flags=0, cas=b"", multiple=False
+            )
+        self._current.append(cmdObj)
+        return cmdObj._deferred
+
+    def stats(self, arg=None):
+        """
+        Get some stats from the server. It will be available as a dict.
+
+        @param arg: An optional additional string which will be sent along
+            with the I{stats} command.  The interpretation of this value by
+            the server is left undefined by the memcache protocol
+            specification.
+        @type arg: L{None} or L{bytes}
+
+        @return: a deferred that will fire with a L{dict} of the available
+            statistics.
+        @rtype: L{Deferred}
+        """
+        if arg:
+            cmd = b"stats " + arg
+        else:
+            cmd = b"stats"
+        if self._disconnected:
+            return fail(RuntimeError("not connected"))
+        self.sendLine(cmd)
+        cmdObj = Command(b"stats", values={})
+        self._current.append(cmdObj)
+        return cmdObj._deferred
+
+    def version(self):
+        """
+        Get the version of the server.
+
+        @return: a deferred that will fire with the string value of the
+            version.
+        @rtype: L{Deferred}
+        """
+        if self._disconnected:
+            return fail(RuntimeError("not connected"))
+        self.sendLine(b"version")
+        cmdObj = Command(b"version")
+        self._current.append(cmdObj)
+        return cmdObj._deferred
+
+    def delete(self, key):
+        """
+        Delete an existing C{key}.
+
+        @param key: the key to delete.
+        @type key: L{bytes}
+
+        @return: a deferred that will be called back with C{True} if the key
+            was successfully deleted, or C{False} if not.
+        @rtype: L{Deferred}
+        """
+        if self._disconnected:
+            return fail(RuntimeError("not connected"))
+        if not isinstance(key, bytes):
+            return fail(
+                ClientError(f"Invalid type for key: {type(key)}, expecting bytes")
+            )
+        self.sendLine(b"delete " + key)
+        cmdObj = Command(b"delete", key=key)
+        self._current.append(cmdObj)
+        return cmdObj._deferred
+
+    def flushAll(self):
+        """
+        Flush all cached values.
+
+        @return: a deferred that will be called back with C{True} when the
+            operation has succeeded.
+        @rtype: L{Deferred}
+        """
+        if self._disconnected:
+            return fail(RuntimeError("not connected"))
+        self.sendLine(b"flush_all")
+        cmdObj = Command(b"flush_all")
+        self._current.append(cmdObj)
+        return cmdObj._deferred
+
+
+__all__ = [
+    "MemCacheProtocol",
+    "DEFAULT_PORT",
+    "NoSuchCommand",
+    "ClientError",
+    "ServerError",
+]

backend/lib/python3.12/site-packages/twisted/protocols/pcp.py

@@ -0,0 +1,211 @@
+# -*- test-case-name: twisted.test.test_pcp -*-
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""
+Producer-Consumer Proxy.
+"""
+
+from zope.interface import implementer
+
+from twisted.internet import interfaces
+
+
+@implementer(interfaces.IProducer, interfaces.IConsumer)
+class BasicProducerConsumerProxy:
+    """
+    I can act as a man in the middle between any Producer and Consumer.
+
+    @ivar producer: the Producer I subscribe to.
+    @type producer: L{IProducer<interfaces.IProducer>}
+    @ivar consumer: the Consumer I publish to.
+    @type consumer: L{IConsumer<interfaces.IConsumer>}
+    @ivar paused: As a Producer, am I paused?
+    @type paused: bool
+    """
+
+    consumer = None
+    producer = None
+    producerIsStreaming = None
+    iAmStreaming = True
+    outstandingPull = False
+    paused = False
+    stopped = False
+
+    def __init__(self, consumer):
+        self._buffer = []
+        if consumer is not None:
+            self.consumer = consumer
+            consumer.registerProducer(self, self.iAmStreaming)
+
+    # Producer methods:
+
+    def pauseProducing(self):
+        self.paused = True
+        if self.producer:
+            self.producer.pauseProducing()
+
+    def resumeProducing(self):
+        self.paused = False
+        if self._buffer:
+            # TODO: Check to see if consumer supports writeSeq.
+            self.consumer.write("".join(self._buffer))
+            self._buffer[:] = []
+        else:
+            if not self.iAmStreaming:
+                self.outstandingPull = True
+
+        if self.producer is not None:
+            self.producer.resumeProducing()
+
+    def stopProducing(self):
+        if self.producer is not None:
+            self.producer.stopProducing()
+        if self.consumer is not None:
+            del self.consumer
+
+    # Consumer methods:
+
+    def write(self, data):
+        if self.paused or (not self.iAmStreaming and not self.outstandingPull):
+            # We could use that fifo queue here.
+            self._buffer.append(data)
+
+        elif self.consumer is not None:
+            self.consumer.write(data)
+            self.outstandingPull = False
+
+    def finish(self):
+        if self.consumer is not None:
+            self.consumer.finish()
+        self.unregisterProducer()
+
+    def registerProducer(self, producer, streaming):
+        self.producer = producer
+        self.producerIsStreaming = streaming
+
+    def unregisterProducer(self):
+        if self.producer is not None:
+            del self.producer
+            del self.producerIsStreaming
+        if self.consumer:
+            self.consumer.unregisterProducer()
+
+    def __repr__(self) -> str:
+        return f"<{self.__class__}@{id(self):x} around {self.consumer}>"
+
+
+class ProducerConsumerProxy(BasicProducerConsumerProxy):
+    """ProducerConsumerProxy with a finite buffer.
+
+    When my buffer fills up, I have my parent Producer pause until my buffer
+    has room in it again.
+    """
+
+    # Copies much from abstract.FileDescriptor
+    bufferSize = 2**2**2**2
+
+    producerPaused = False
+    unregistered = False
+
+    def pauseProducing(self):
+        # Does *not* call up to ProducerConsumerProxy to relay the pause
+        # message through to my parent Producer.
+        self.paused = True
+
+    def resumeProducing(self):
+        self.paused = False
+        if self._buffer:
+            data = "".join(self._buffer)
+            bytesSent = self._writeSomeData(data)
+            if bytesSent < len(data):
+                unsent = data[bytesSent:]
+                assert (
+                    not self.iAmStreaming
+                ), "Streaming producer did not write all its data."
+                self._buffer[:] = [unsent]
+            else:
+                self._buffer[:] = []
+        else:
+            bytesSent = 0
+
+        if (
+            self.unregistered
+            and bytesSent
+            and not self._buffer
+            and self.consumer is not None
+        ):
+            self.consumer.unregisterProducer()
+
+        if not self.iAmStreaming:
+            self.outstandingPull = not bytesSent
+
+        if self.producer is not None:
+            bytesBuffered = sum(len(s) for s in self._buffer)
+            # TODO: You can see here the potential for high and low
+            # watermarks, where bufferSize would be the high mark when we
+            # ask the upstream producer to pause, and we wouldn't have
+            # it resume again until it hit the low mark.  Or if producer
+            # is Pull, maybe we'd like to pull from it as much as necessary
+            # to keep our buffer full to the low mark, so we're never caught
+            # without something to send.
+            if self.producerPaused and (bytesBuffered < self.bufferSize):
+                # Now that our buffer is empty,
+                self.producerPaused = False
+                self.producer.resumeProducing()
+            elif self.outstandingPull:
+                # I did not have any data to write in response to a pull,
+                # so I'd better pull some myself.
+                self.producer.resumeProducing()
+
+    def write(self, data):
+        if self.paused or (not self.iAmStreaming and not self.outstandingPull):
+            # We could use that fifo queue here.
+            self._buffer.append(data)
+
+        elif self.consumer is not None:
+            assert (
+                not self._buffer
+            ), "Writing fresh data to consumer before my buffer is empty!"
+            # I'm going to use _writeSomeData here so that there is only one
+            # path to self.consumer.write.  But it doesn't actually make sense,
+            # if I am streaming, for some data to not be all data.  But maybe I
+            # am not streaming, but I am writing here anyway, because there was
+            # an earlier request for data which was not answered.
+            bytesSent = self._writeSomeData(data)
+            self.outstandingPull = False
+            if not bytesSent == len(data):
+                assert (
+                    not self.iAmStreaming
+                ), "Streaming producer did not write all its data."
+                self._buffer.append(data[bytesSent:])
+
+        if (self.producer is not None) and self.producerIsStreaming:
+            bytesBuffered = sum(len(s) for s in self._buffer)
+            if bytesBuffered >= self.bufferSize:
+                self.producer.pauseProducing()
+                self.producerPaused = True
+
+    def registerProducer(self, producer, streaming):
+        self.unregistered = False
+        BasicProducerConsumerProxy.registerProducer(self, producer, streaming)
+        if not streaming:
+            producer.resumeProducing()
+
+    def unregisterProducer(self):
+        if self.producer is not None:
+            del self.producer
+            del self.producerIsStreaming
+        self.unregistered = True
+        if self.consumer and not self._buffer:
+            self.consumer.unregisterProducer()
+
+    def _writeSomeData(self, data):
+        """Write as much of this data as possible.
+
+        @returns: The number of bytes written.
+        """
+        if self.consumer is None:
+            return 0
+        self.consumer.write(data)
+        return len(data)

backend/lib/python3.12/site-packages/twisted/protocols/policies.py

@@ -0,0 +1,696 @@
+# -*- test-case-name: twisted.test.test_policies -*-
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""
+Resource limiting policies.
+
+@seealso: See also L{twisted.protocols.htb} for rate limiting.
+"""
+
+
+# system imports
+import sys
+from typing import Optional, Type
+
+from zope.interface import directlyProvides, providedBy
+
+from twisted.internet import error, interfaces
+from twisted.internet.interfaces import ILoggingContext
+
+# twisted imports
+from twisted.internet.protocol import ClientFactory, Protocol, ServerFactory
+from twisted.python import log
+
+
+def _wrappedLogPrefix(wrapper, wrapped):
+    """
+    Compute a log prefix for a wrapper and the object it wraps.
+
+    @rtype: C{str}
+    """
+    if ILoggingContext.providedBy(wrapped):
+        logPrefix = wrapped.logPrefix()
+    else:
+        logPrefix = wrapped.__class__.__name__
+    return f"{logPrefix} ({wrapper.__class__.__name__})"
+
+
+class ProtocolWrapper(Protocol):
+    """
+    Wraps protocol instances and acts as their transport as well.
+
+    @ivar wrappedProtocol: An L{IProtocol<twisted.internet.interfaces.IProtocol>}
+        provider to which L{IProtocol<twisted.internet.interfaces.IProtocol>}
+        method calls onto this L{ProtocolWrapper} will be proxied.
+
+    @ivar factory: The L{WrappingFactory} which created this
+        L{ProtocolWrapper}.
+    """
+
+    disconnecting = 0
+
+    def __init__(
+        self, factory: "WrappingFactory", wrappedProtocol: interfaces.IProtocol
+    ):
+        self.wrappedProtocol = wrappedProtocol
+        self.factory = factory
+
+    def logPrefix(self):
+        """
+        Use a customized log prefix mentioning both the wrapped protocol and
+        the current one.
+        """
+        return _wrappedLogPrefix(self, self.wrappedProtocol)
+
+    def makeConnection(self, transport):
+        """
+        When a connection is made, register this wrapper with its factory,
+        save the real transport, and connect the wrapped protocol to this
+        L{ProtocolWrapper} to intercept any transport calls it makes.
+        """
+        directlyProvides(self, providedBy(transport))
+        Protocol.makeConnection(self, transport)
+        self.factory.registerProtocol(self)
+        self.wrappedProtocol.makeConnection(self)
+
+    # Transport relaying
+
+    def write(self, data):
+        self.transport.write(data)
+
+    def writeSequence(self, data):
+        self.transport.writeSequence(data)
+
+    def loseConnection(self):
+        self.disconnecting = 1
+        self.transport.loseConnection()
+
+    def getPeer(self):
+        return self.transport.getPeer()
+
+    def getHost(self):
+        return self.transport.getHost()
+
+    def registerProducer(self, producer, streaming):
+        self.transport.registerProducer(producer, streaming)
+
+    def unregisterProducer(self):
+        self.transport.unregisterProducer()
+
+    def stopConsuming(self):
+        self.transport.stopConsuming()
+
+    def __getattr__(self, name):
+        return getattr(self.transport, name)
+
+    # Protocol relaying
+
+    def dataReceived(self, data):
+        self.wrappedProtocol.dataReceived(data)
+
+    def connectionLost(self, reason):
+        self.factory.unregisterProtocol(self)
+        self.wrappedProtocol.connectionLost(reason)
+
+        # Breaking reference cycle between self and wrappedProtocol.
+        self.wrappedProtocol = None
+
+
+class WrappingFactory(ClientFactory):
+    """
+    Wraps a factory and its protocols, and keeps track of them.
+    """
+
+    protocol: Type[Protocol] = ProtocolWrapper
+
+    def __init__(self, wrappedFactory):
+        self.wrappedFactory = wrappedFactory
+        self.protocols = {}
+
+    def logPrefix(self):
+        """
+        Generate a log prefix mentioning both the wrapped factory and this one.
+        """
+        return _wrappedLogPrefix(self, self.wrappedFactory)
+
+    def doStart(self):
+        self.wrappedFactory.doStart()
+        ClientFactory.doStart(self)
+
+    def doStop(self):
+        self.wrappedFactory.doStop()
+        ClientFactory.doStop(self)
+
+    def startedConnecting(self, connector):
+        self.wrappedFactory.startedConnecting(connector)
+
+    def clientConnectionFailed(self, connector, reason):
+        self.wrappedFactory.clientConnectionFailed(connector, reason)
+
+    def clientConnectionLost(self, connector, reason):
+        self.wrappedFactory.clientConnectionLost(connector, reason)
+
+    def buildProtocol(self, addr):
+        return self.protocol(self, self.wrappedFactory.buildProtocol(addr))
+
+    def registerProtocol(self, p):
+        """
+        Called by protocol to register itself.
+        """
+        self.protocols[p] = 1
+
+    def unregisterProtocol(self, p):
+        """
+        Called by protocols when they go away.
+        """
+        del self.protocols[p]
+
+
+class ThrottlingProtocol(ProtocolWrapper):
+    """
+    Protocol for L{ThrottlingFactory}.
+    """
+
+    # wrap API for tracking bandwidth
+
+    def write(self, data):
+        self.factory.registerWritten(len(data))
+        ProtocolWrapper.write(self, data)
+
+    def writeSequence(self, seq):
+        self.factory.registerWritten(sum(map(len, seq)))
+        ProtocolWrapper.writeSequence(self, seq)
+
+    def dataReceived(self, data):
+        self.factory.registerRead(len(data))
+        ProtocolWrapper.dataReceived(self, data)
+
+    def registerProducer(self, producer, streaming):
+        self.producer = producer
+        ProtocolWrapper.registerProducer(self, producer, streaming)
+
+    def unregisterProducer(self):
+        del self.producer
+        ProtocolWrapper.unregisterProducer(self)
+
+    def throttleReads(self):
+        self.transport.pauseProducing()
+
+    def unthrottleReads(self):
+        self.transport.resumeProducing()
+
+    def throttleWrites(self):
+        if hasattr(self, "producer"):
+            self.producer.pauseProducing()
+
+    def unthrottleWrites(self):
+        if hasattr(self, "producer"):
+            self.producer.resumeProducing()
+
+
+class ThrottlingFactory(WrappingFactory):
+    """
+    Throttles bandwidth and number of connections.
+
+    Write bandwidth will only be throttled if there is a producer
+    registered.
+    """
+
+    protocol = ThrottlingProtocol
+
+    def __init__(
+        self,
+        wrappedFactory,
+        maxConnectionCount=sys.maxsize,
+        readLimit=None,
+        writeLimit=None,
+    ):
+        WrappingFactory.__init__(self, wrappedFactory)
+        self.connectionCount = 0
+        self.maxConnectionCount = maxConnectionCount
+        self.readLimit = readLimit  # max bytes we should read per second
+        self.writeLimit = writeLimit  # max bytes we should write per second
+        self.readThisSecond = 0
+        self.writtenThisSecond = 0
+        self.unthrottleReadsID = None
+        self.checkReadBandwidthID = None
+        self.unthrottleWritesID = None
+        self.checkWriteBandwidthID = None
+
+    def callLater(self, period, func):
+        """
+        Wrapper around
+        L{reactor.callLater<twisted.internet.interfaces.IReactorTime.callLater>}
+        for test purpose.
+        """
+        from twisted.internet import reactor
+
+        return reactor.callLater(period, func)
+
+    def registerWritten(self, length):
+        """
+        Called by protocol to tell us more bytes were written.
+        """
+        self.writtenThisSecond += length
+
+    def registerRead(self, length):
+        """
+        Called by protocol to tell us more bytes were read.
+        """
+        self.readThisSecond += length
+
+    def checkReadBandwidth(self):
+        """
+        Checks if we've passed bandwidth limits.
+        """
+        if self.readThisSecond > self.readLimit:
+            self.throttleReads()
+            throttleTime = (float(self.readThisSecond) / self.readLimit) - 1.0
+            self.unthrottleReadsID = self.callLater(throttleTime, self.unthrottleReads)
+        self.readThisSecond = 0
+        self.checkReadBandwidthID = self.callLater(1, self.checkReadBandwidth)
+
+    def checkWriteBandwidth(self):
+        if self.writtenThisSecond > self.writeLimit:
+            self.throttleWrites()
+            throttleTime = (float(self.writtenThisSecond) / self.writeLimit) - 1.0
+            self.unthrottleWritesID = self.callLater(
+                throttleTime, self.unthrottleWrites
+            )
+        # reset for next round
+        self.writtenThisSecond = 0
+        self.checkWriteBandwidthID = self.callLater(1, self.checkWriteBandwidth)
+
+    def throttleReads(self):
+        """
+        Throttle reads on all protocols.
+        """
+        log.msg("Throttling reads on %s" % self)
+        for p in self.protocols.keys():
+            p.throttleReads()
+
+    def unthrottleReads(self):
+        """
+        Stop throttling reads on all protocols.
+        """
+        self.unthrottleReadsID = None
+        log.msg("Stopped throttling reads on %s" % self)
+        for p in self.protocols.keys():
+            p.unthrottleReads()
+
+    def throttleWrites(self):
+        """
+        Throttle writes on all protocols.
+        """
+        log.msg("Throttling writes on %s" % self)
+        for p in self.protocols.keys():
+            p.throttleWrites()
+
+    def unthrottleWrites(self):
+        """
+        Stop throttling writes on all protocols.
+        """
+        self.unthrottleWritesID = None
+        log.msg("Stopped throttling writes on %s" % self)
+        for p in self.protocols.keys():
+            p.unthrottleWrites()
+
+    def buildProtocol(self, addr):
+        if self.connectionCount == 0:
+            if self.readLimit is not None:
+                self.checkReadBandwidth()
+            if self.writeLimit is not None:
+                self.checkWriteBandwidth()
+
+        if self.connectionCount < self.maxConnectionCount:
+            self.connectionCount += 1
+            return WrappingFactory.buildProtocol(self, addr)
+        else:
+            log.msg("Max connection count reached!")
+            return None
+
+    def unregisterProtocol(self, p):
+        WrappingFactory.unregisterProtocol(self, p)
+        self.connectionCount -= 1
+        if self.connectionCount == 0:
+            if self.unthrottleReadsID is not None:
+                self.unthrottleReadsID.cancel()
+            if self.checkReadBandwidthID is not None:
+                self.checkReadBandwidthID.cancel()
+            if self.unthrottleWritesID is not None:
+                self.unthrottleWritesID.cancel()
+            if self.checkWriteBandwidthID is not None:
+                self.checkWriteBandwidthID.cancel()
+
+
+class SpewingProtocol(ProtocolWrapper):
+    def dataReceived(self, data):
+        log.msg("Received: %r" % data)
+        ProtocolWrapper.dataReceived(self, data)
+
+    def write(self, data):
+        log.msg("Sending: %r" % data)
+        ProtocolWrapper.write(self, data)
+
+
+class SpewingFactory(WrappingFactory):
+    protocol = SpewingProtocol
+
+
+class LimitConnectionsByPeer(WrappingFactory):
+    maxConnectionsPerPeer = 5
+
+    def startFactory(self):
+        self.peerConnections = {}
+
+    def buildProtocol(self, addr):
+        peerHost = addr[0]
+        connectionCount = self.peerConnections.get(peerHost, 0)
+        if connectionCount >= self.maxConnectionsPerPeer:
+            return None
+        self.peerConnections[peerHost] = connectionCount + 1
+        return WrappingFactory.buildProtocol(self, addr)
+
+    def unregisterProtocol(self, p):
+        peerHost = p.getPeer()[1]
+        self.peerConnections[peerHost] -= 1
+        if self.peerConnections[peerHost] == 0:
+            del self.peerConnections[peerHost]
+
+
+class LimitTotalConnectionsFactory(ServerFactory):
+    """
+    Factory that limits the number of simultaneous connections.
+
+    @type connectionCount: C{int}
+    @ivar connectionCount: number of current connections.
+    @type connectionLimit: C{int} or L{None}
+    @cvar connectionLimit: maximum number of connections.
+    @type overflowProtocol: L{Protocol} or L{None}
+    @cvar overflowProtocol: Protocol to use for new connections when
+        connectionLimit is exceeded.  If L{None} (the default value), excess
+        connections will be closed immediately.
+    """
+
+    connectionCount = 0
+    connectionLimit = None
+    overflowProtocol: Optional[Type[Protocol]] = None
+
+    def buildProtocol(self, addr):
+        if self.connectionLimit is None or self.connectionCount < self.connectionLimit:
+            # Build the normal protocol
+            wrappedProtocol = self.protocol()
+        elif self.overflowProtocol is None:
+            # Just drop the connection
+            return None
+        else:
+            # Too many connections, so build the overflow protocol
+            wrappedProtocol = self.overflowProtocol()
+
+        wrappedProtocol.factory = self
+        protocol = ProtocolWrapper(self, wrappedProtocol)
+        self.connectionCount += 1
+        return protocol
+
+    def registerProtocol(self, p):
+        pass
+
+    def unregisterProtocol(self, p):
+        self.connectionCount -= 1
+
+
+class TimeoutProtocol(ProtocolWrapper):
+    """
+    Protocol that automatically disconnects when the connection is idle.
+    """
+
+    def __init__(self, factory, wrappedProtocol, timeoutPeriod):
+        """
+        Constructor.
+
+        @param factory: An L{TimeoutFactory}.
+        @param wrappedProtocol: A L{Protocol} to wrapp.
+        @param timeoutPeriod: Number of seconds to wait for activity before
+            timing out.
+        """
+        ProtocolWrapper.__init__(self, factory, wrappedProtocol)
+        self.timeoutCall = None
+        self.timeoutPeriod = None
+        self.setTimeout(timeoutPeriod)
+
+    def setTimeout(self, timeoutPeriod=None):
+        """
+        Set a timeout.
+
+        This will cancel any existing timeouts.
+
+        @param timeoutPeriod: If not L{None}, change the timeout period.
+            Otherwise, use the existing value.
+        """
+        self.cancelTimeout()
+        self.timeoutPeriod = timeoutPeriod
+        if timeoutPeriod is not None:
+            self.timeoutCall = self.factory.callLater(
+                self.timeoutPeriod, self.timeoutFunc
+            )
+
+    def cancelTimeout(self):
+        """
+        Cancel the timeout.
+
+        If the timeout was already cancelled, this does nothing.
+        """
+        self.timeoutPeriod = None
+        if self.timeoutCall:
+            try:
+                self.timeoutCall.cancel()
+            except (error.AlreadyCalled, error.AlreadyCancelled):
+                pass
+            self.timeoutCall = None
+
+    def resetTimeout(self):
+        """
+        Reset the timeout, usually because some activity just happened.
+        """
+        if self.timeoutCall:
+            self.timeoutCall.reset(self.timeoutPeriod)
+
+    def write(self, data):
+        self.resetTimeout()
+        ProtocolWrapper.write(self, data)
+
+    def writeSequence(self, seq):
+        self.resetTimeout()
+        ProtocolWrapper.writeSequence(self, seq)
+
+    def dataReceived(self, data):
+        self.resetTimeout()
+        ProtocolWrapper.dataReceived(self, data)
+
+    def connectionLost(self, reason):
+        self.cancelTimeout()
+        ProtocolWrapper.connectionLost(self, reason)
+
+    def timeoutFunc(self):
+        """
+        This method is called when the timeout is triggered.
+
+        By default it calls I{loseConnection}.  Override this if you want
+        something else to happen.
+        """
+        self.loseConnection()
+
+
+class TimeoutFactory(WrappingFactory):
+    """
+    Factory for TimeoutWrapper.
+    """
+
+    protocol = TimeoutProtocol
+
+    def __init__(self, wrappedFactory, timeoutPeriod=30 * 60):
+        self.timeoutPeriod = timeoutPeriod
+        WrappingFactory.__init__(self, wrappedFactory)
+
+    def buildProtocol(self, addr):
+        return self.protocol(
+            self,
+            self.wrappedFactory.buildProtocol(addr),
+            timeoutPeriod=self.timeoutPeriod,
+        )
+
+    def callLater(self, period, func):
+        """
+        Wrapper around
+        L{reactor.callLater<twisted.internet.interfaces.IReactorTime.callLater>}
+        for test purpose.
+        """
+        from twisted.internet import reactor
+
+        return reactor.callLater(period, func)
+
+
+class TrafficLoggingProtocol(ProtocolWrapper):
+    def __init__(self, factory, wrappedProtocol, logfile, lengthLimit=None, number=0):
+        """
+        @param factory: factory which created this protocol.
+        @type factory: L{protocol.Factory}.
+        @param wrappedProtocol: the underlying protocol.
+        @type wrappedProtocol: C{protocol.Protocol}.
+        @param logfile: file opened for writing used to write log messages.
+        @type logfile: C{file}
+        @param lengthLimit: maximum size of the datareceived logged.
+        @type lengthLimit: C{int}
+        @param number: identifier of the connection.
+        @type number: C{int}.
+        """
+        ProtocolWrapper.__init__(self, factory, wrappedProtocol)
+        self.logfile = logfile
+        self.lengthLimit = lengthLimit
+        self._number = number
+
+    def _log(self, line):
+        self.logfile.write(line + "\n")
+        self.logfile.flush()
+
+    def _mungeData(self, data):
+        if self.lengthLimit and len(data) > self.lengthLimit:
+            data = data[: self.lengthLimit - 12] + "<... elided>"
+        return data
+
+    # IProtocol
+    def connectionMade(self):
+        self._log("*")
+        return ProtocolWrapper.connectionMade(self)
+
+    def dataReceived(self, data):
+        self._log("C %d: %r" % (self._number, self._mungeData(data)))
+        return ProtocolWrapper.dataReceived(self, data)
+
+    def connectionLost(self, reason):
+        self._log("C %d: %r" % (self._number, reason))
+        return ProtocolWrapper.connectionLost(self, reason)
+
+    # ITransport
+    def write(self, data):
+        self._log("S %d: %r" % (self._number, self._mungeData(data)))
+        return ProtocolWrapper.write(self, data)
+
+    def writeSequence(self, iovec):
+        self._log("SV %d: %r" % (self._number, [self._mungeData(d) for d in iovec]))
+        return ProtocolWrapper.writeSequence(self, iovec)
+
+    def loseConnection(self):
+        self._log("S %d: *" % (self._number,))
+        return ProtocolWrapper.loseConnection(self)
+
+
+class TrafficLoggingFactory(WrappingFactory):
+    protocol = TrafficLoggingProtocol
+
+    _counter = 0
+
+    def __init__(self, wrappedFactory, logfilePrefix, lengthLimit=None):
+        self.logfilePrefix = logfilePrefix
+        self.lengthLimit = lengthLimit
+        WrappingFactory.__init__(self, wrappedFactory)
+
+    def open(self, name):
+        return open(name, "w")
+
+    def buildProtocol(self, addr):
+        self._counter += 1
+        logfile = self.open(self.logfilePrefix + "-" + str(self._counter))
+        return self.protocol(
+            self,
+            self.wrappedFactory.buildProtocol(addr),
+            logfile,
+            self.lengthLimit,
+            self._counter,
+        )
+
+    def resetCounter(self):
+        """
+        Reset the value of the counter used to identify connections.
+        """
+        self._counter = 0
+
+
+class TimeoutMixin:
+    """
+    Mixin for protocols which wish to timeout connections.
+
+    Protocols that mix this in have a single timeout, set using L{setTimeout}.
+    When the timeout is hit, L{timeoutConnection} is called, which, by
+    default, closes the connection.
+
+    @cvar timeOut: The number of seconds after which to timeout the connection.
+    """
+
+    timeOut: Optional[int] = None
+
+    __timeoutCall = None
+
+    def callLater(self, period, func):
+        """
+        Wrapper around
+        L{reactor.callLater<twisted.internet.interfaces.IReactorTime.callLater>}
+        for test purpose.
+        """
+        from twisted.internet import reactor
+
+        return reactor.callLater(period, func)
+
+    def resetTimeout(self):
+        """
+        Reset the timeout count down.
+
+        If the connection has already timed out, then do nothing.  If the
+        timeout has been cancelled (probably using C{setTimeout(None)}), also
+        do nothing.
+
+        It's often a good idea to call this when the protocol has received
+        some meaningful input from the other end of the connection.  "I've got
+        some data, they're still there, reset the timeout".
+        """
+        if self.__timeoutCall is not None and self.timeOut is not None:
+            self.__timeoutCall.reset(self.timeOut)
+
+    def setTimeout(self, period):
+        """
+        Change the timeout period
+
+        @type period: C{int} or L{None}
+        @param period: The period, in seconds, to change the timeout to, or
+        L{None} to disable the timeout.
+        """
+        prev = self.timeOut
+        self.timeOut = period
+
+        if self.__timeoutCall is not None:
+            if period is None:
+                try:
+                    self.__timeoutCall.cancel()
+                except (error.AlreadyCancelled, error.AlreadyCalled):
+                    # Do nothing if the call was already consumed.
+                    pass
+                self.__timeoutCall = None
+            else:
+                self.__timeoutCall.reset(period)
+        elif period is not None:
+            self.__timeoutCall = self.callLater(period, self.__timedOut)
+
+        return prev
+
+    def __timedOut(self):
+        self.__timeoutCall = None
+        self.timeoutConnection()
+
+    def timeoutConnection(self):
+        """
+        Called when the connection times out.
+
+        Override to define behavior other than dropping the connection.
+        """
+        self.transport.loseConnection()

backend/lib/python3.12/site-packages/twisted/protocols/portforward.py

@@ -0,0 +1,90 @@
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""
+A simple port forwarder.
+"""
+
+# Twisted imports
+from twisted.internet import protocol
+from twisted.python import log
+
+
+class Proxy(protocol.Protocol):
+    noisy = True
+
+    peer = None
+
+    def setPeer(self, peer):
+        self.peer = peer
+
+    def connectionLost(self, reason):
+        if self.peer is not None:
+            self.peer.transport.loseConnection()
+            self.peer = None
+        elif self.noisy:
+            log.msg(f"Unable to connect to peer: {reason}")
+
+    def dataReceived(self, data):
+        self.peer.transport.write(data)
+
+
+class ProxyClient(Proxy):
+    def connectionMade(self):
+        self.peer.setPeer(self)
+
+        # Wire this and the peer transport together to enable
+        # flow control (this stops connections from filling
+        # this proxy memory when one side produces data at a
+        # higher rate than the other can consume).
+        self.transport.registerProducer(self.peer.transport, True)
+        self.peer.transport.registerProducer(self.transport, True)
+
+        # We're connected, everybody can read to their hearts content.
+        self.peer.transport.resumeProducing()
+
+
+class ProxyClientFactory(protocol.ClientFactory):
+    protocol = ProxyClient
+
+    def setServer(self, server):
+        self.server = server
+
+    def buildProtocol(self, *args, **kw):
+        prot = protocol.ClientFactory.buildProtocol(self, *args, **kw)
+        prot.setPeer(self.server)
+        return prot
+
+    def clientConnectionFailed(self, connector, reason):
+        self.server.transport.loseConnection()
+
+
+class ProxyServer(Proxy):
+    clientProtocolFactory = ProxyClientFactory
+    reactor = None
+
+    def connectionMade(self):
+        # Don't read anything from the connecting client until we have
+        # somewhere to send it to.
+        self.transport.pauseProducing()
+
+        client = self.clientProtocolFactory()
+        client.setServer(self)
+
+        if self.reactor is None:
+            from twisted.internet import reactor
+
+            self.reactor = reactor
+        self.reactor.connectTCP(self.factory.host, self.factory.port, client)
+
+
+class ProxyFactory(protocol.Factory):
+    """
+    Factory for port forwarder.
+    """
+
+    protocol = ProxyServer
+
+    def __init__(self, host, port):
+        self.host = host
+        self.port = port

backend/lib/python3.12/site-packages/twisted/protocols/postfix.py

@@ -0,0 +1,137 @@
+# -*- test-case-name: twisted.test.test_postfix -*-
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""
+Postfix mail transport agent related protocols.
+"""
+from __future__ import annotations
+
+import sys
+from collections import UserDict
+from typing import TYPE_CHECKING, Union
+from urllib.parse import quote as _quote, unquote as _unquote
+
+from twisted.internet import defer, protocol
+from twisted.protocols import basic, policies
+from twisted.python import log
+
+
+# urllib's quote functions just happen to match
+# the postfix semantics.
+def quote(s):
+    quoted = _quote(s)
+    if isinstance(quoted, str):
+        quoted = quoted.encode("ascii")
+    return quoted
+
+
+def unquote(s):
+    if isinstance(s, bytes):
+        s = s.decode("ascii")
+    quoted = _unquote(s)
+    return quoted.encode("ascii")
+
+
+class PostfixTCPMapServer(basic.LineReceiver, policies.TimeoutMixin):
+    """
+    Postfix mail transport agent TCP map protocol implementation.
+
+    Receive requests for data matching given key via lineReceived,
+    asks it's factory for the data with self.factory.get(key), and
+    returns the data to the requester. None means no entry found.
+
+    You can use postfix's postmap to test the map service::
+
+    /usr/sbin/postmap -q KEY tcp:localhost:4242
+
+    """
+
+    timeout = 600
+    delimiter = b"\n"
+
+    def connectionMade(self):
+        self.setTimeout(self.timeout)
+
+    def sendCode(self, code, message=b""):
+        """
+        Send an SMTP-like code with a message.
+        """
+        self.sendLine(str(code).encode("ascii") + b" " + message)
+
+    def lineReceived(self, line):
+        self.resetTimeout()
+        try:
+            request, params = line.split(None, 1)
+        except ValueError:
+            request = line
+            params = None
+        try:
+            f = getattr(self, "do_" + request.decode("ascii"))
+        except AttributeError:
+            self.sendCode(400, b"unknown command")
+        else:
+            try:
+                f(params)
+            except BaseException:
+                excInfo = str(sys.exc_info()[1]).encode("ascii")
+                self.sendCode(400, b"Command " + request + b" failed: " + excInfo)
+
+    def do_get(self, key):
+        if key is None:
+            self.sendCode(400, b"Command 'get' takes 1 parameters.")
+        else:
+            d = defer.maybeDeferred(self.factory.get, key)
+            d.addCallbacks(self._cbGot, self._cbNot)
+            d.addErrback(log.err)
+
+    def _cbNot(self, fail):
+        msg = fail.getErrorMessage().encode("ascii")
+        self.sendCode(400, msg)
+
+    def _cbGot(self, value):
+        if value is None:
+            self.sendCode(500)
+        else:
+            self.sendCode(200, quote(value))
+
+    def do_put(self, keyAndValue):
+        if keyAndValue is None:
+            self.sendCode(400, b"Command 'put' takes 2 parameters.")
+        else:
+            try:
+                key, value = keyAndValue.split(None, 1)
+            except ValueError:
+                self.sendCode(400, b"Command 'put' takes 2 parameters.")
+            else:
+                self.sendCode(500, b"put is not implemented yet.")
+
+
+if TYPE_CHECKING or sys.version_info >= (3, 9):
+    _PostfixTCPMapDict = UserDict[bytes, Union[str, bytes]]
+else:
+    _PostfixTCPMapDict = UserDict
+
+
+class PostfixTCPMapDictServerFactory(_PostfixTCPMapDict, protocol.ServerFactory):
+    """
+    An in-memory dictionary factory for PostfixTCPMapServer.
+    """
+
+    protocol = PostfixTCPMapServer
+
+
+class PostfixTCPMapDeferringDictServerFactory(protocol.ServerFactory):
+    """
+    An in-memory dictionary factory for PostfixTCPMapServer.
+    """
+
+    protocol = PostfixTCPMapServer
+
+    def __init__(self, data=None):
+        self.data = {}
+        if data is not None:
+            self.data.update(data)
+
+    def get(self, key):
+        return defer.succeed(self.data.get(key))

backend/lib/python3.12/site-packages/twisted/protocols/shoutcast.py

@@ -0,0 +1,111 @@
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""
+Chop up shoutcast stream into MP3s and metadata, if available.
+"""
+
+from twisted import copyright
+from twisted.web import http
+
+
+class ShoutcastClient(http.HTTPClient):
+    """
+    Shoutcast HTTP stream.
+
+    Modes can be 'length', 'meta' and 'mp3'.
+
+    See U{http://www.smackfu.com/stuff/programming/shoutcast.html}
+    for details on the protocol.
+    """
+
+    userAgent = "Twisted Shoutcast client " + copyright.version
+
+    def __init__(self, path="/"):
+        self.path = path
+        self.got_metadata = False
+        self.metaint = None
+        self.metamode = "mp3"
+        self.databuffer = ""
+
+    def connectionMade(self):
+        self.sendCommand("GET", self.path)
+        self.sendHeader("User-Agent", self.userAgent)
+        self.sendHeader("Icy-MetaData", "1")
+        self.endHeaders()
+
+    def lineReceived(self, line):
+        # fix shoutcast crappiness
+        if not self.firstLine and line:
+            if len(line.split(": ", 1)) == 1:
+                line = line.replace(":", ": ", 1)
+        http.HTTPClient.lineReceived(self, line)
+
+    def handleHeader(self, key, value):
+        if key.lower() == "icy-metaint":
+            self.metaint = int(value)
+            self.got_metadata = True
+
+    def handleEndHeaders(self):
+        # Lets check if we got metadata, and set the
+        # appropriate handleResponsePart method.
+        if self.got_metadata:
+            # if we have metadata, then it has to be parsed out of the data stream
+            self.handleResponsePart = self.handleResponsePart_with_metadata
+        else:
+            # otherwise, all the data is MP3 data
+            self.handleResponsePart = self.gotMP3Data
+
+    def handleResponsePart_with_metadata(self, data):
+        self.databuffer += data
+        while self.databuffer:
+            stop = getattr(self, "handle_%s" % self.metamode)()
+            if stop:
+                return
+
+    def handle_length(self):
+        self.remaining = ord(self.databuffer[0]) * 16
+        self.databuffer = self.databuffer[1:]
+        self.metamode = "meta"
+
+    def handle_mp3(self):
+        if len(self.databuffer) > self.metaint:
+            self.gotMP3Data(self.databuffer[: self.metaint])
+            self.databuffer = self.databuffer[self.metaint :]
+            self.metamode = "length"
+        else:
+            return 1
+
+    def handle_meta(self):
+        if len(self.databuffer) >= self.remaining:
+            if self.remaining:
+                data = self.databuffer[: self.remaining]
+                self.gotMetaData(self.parseMetadata(data))
+            self.databuffer = self.databuffer[self.remaining :]
+            self.metamode = "mp3"
+        else:
+            return 1
+
+    def parseMetadata(self, data):
+        meta = []
+        for chunk in data.split(";"):
+            chunk = chunk.strip().replace("\x00", "")
+            if not chunk:
+                continue
+            key, value = chunk.split("=", 1)
+            if value.startswith("'") and value.endswith("'"):
+                value = value[1:-1]
+            meta.append((key, value))
+        return meta
+
+    def gotMetaData(self, metadata):
+        """Called with a list of (key, value) pairs of metadata,
+        if metadata is available on the server.
+
+        Will only be called on non-empty metadata.
+        """
+        raise NotImplementedError("implement in subclass")
+
+    def gotMP3Data(self, data):
+        """Called with chunk of MP3 data."""
+        raise NotImplementedError("implement in subclass")

backend/lib/python3.12/site-packages/twisted/protocols/socks.py

@@ -0,0 +1,249 @@
+# -*- test-case-name: twisted.test.test_socks -*-
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""
+Implementation of the SOCKSv4 protocol.
+"""
+
+import socket
+import string
+
+# python imports
+import struct
+import time
+
+# twisted imports
+from twisted.internet import defer, protocol, reactor
+from twisted.python import log
+
+
+class SOCKSv4Outgoing(protocol.Protocol):
+    def __init__(self, socks):
+        self.socks = socks
+
+    def connectionMade(self):
+        peer = self.transport.getPeer()
+        self.socks.makeReply(90, 0, port=peer.port, ip=peer.host)
+        self.socks.otherConn = self
+
+    def connectionLost(self, reason):
+        self.socks.transport.loseConnection()
+
+    def dataReceived(self, data):
+        self.socks.write(data)
+
+    def write(self, data):
+        self.socks.log(self, data)
+        self.transport.write(data)
+
+
+class SOCKSv4Incoming(protocol.Protocol):
+    def __init__(self, socks):
+        self.socks = socks
+        self.socks.otherConn = self
+
+    def connectionLost(self, reason):
+        self.socks.transport.loseConnection()
+
+    def dataReceived(self, data):
+        self.socks.write(data)
+
+    def write(self, data):
+        self.socks.log(self, data)
+        self.transport.write(data)
+
+
+class SOCKSv4(protocol.Protocol):
+    """
+    An implementation of the SOCKSv4 protocol.
+
+    @type logging: L{str} or L{None}
+    @ivar logging: If not L{None}, the name of the logfile to which connection
+        information will be written.
+
+    @type reactor: object providing L{twisted.internet.interfaces.IReactorTCP}
+    @ivar reactor: The reactor used to create connections.
+
+    @type buf: L{str}
+    @ivar buf: Part of a SOCKSv4 connection request.
+
+    @type otherConn: C{SOCKSv4Incoming}, C{SOCKSv4Outgoing} or L{None}
+    @ivar otherConn: Until the connection has been established, C{otherConn} is
+        L{None}. After that, it is the proxy-to-destination protocol instance
+        along which the client's connection is being forwarded.
+    """
+
+    def __init__(self, logging=None, reactor=reactor):
+        self.logging = logging
+        self.reactor = reactor
+
+    def connectionMade(self):
+        self.buf = b""
+        self.otherConn = None
+
+    def dataReceived(self, data):
+        """
+        Called whenever data is received.
+
+        @type data: L{bytes}
+        @param data: Part or all of a SOCKSv4 packet.
+        """
+        if self.otherConn:
+            self.otherConn.write(data)
+            return
+        self.buf = self.buf + data
+        completeBuffer = self.buf
+        if b"\000" in self.buf[8:]:
+            head, self.buf = self.buf[:8], self.buf[8:]
+            version, code, port = struct.unpack("!BBH", head[:4])
+            user, self.buf = self.buf.split(b"\000", 1)
+            if head[4:7] == b"\000\000\000" and head[7:8] != b"\000":
+                # An IP address of the form 0.0.0.X, where X is non-zero,
+                # signifies that this is a SOCKSv4a packet.
+                # If the complete packet hasn't been received, restore the
+                # buffer and wait for it.
+                if b"\000" not in self.buf:
+                    self.buf = completeBuffer
+                    return
+                server, self.buf = self.buf.split(b"\000", 1)
+                d = self.reactor.resolve(server)
+                d.addCallback(self._dataReceived2, user, version, code, port)
+                d.addErrback(lambda result, self=self: self.makeReply(91))
+                return
+            else:
+                server = socket.inet_ntoa(head[4:8])
+
+            self._dataReceived2(server, user, version, code, port)
+
+    def _dataReceived2(self, server, user, version, code, port):
+        """
+        The second half of the SOCKS connection setup. For a SOCKSv4 packet this
+        is after the server address has been extracted from the header. For a
+        SOCKSv4a packet this is after the host name has been resolved.
+
+        @type server: L{str}
+        @param server: The IP address of the destination, represented as a
+            dotted quad.
+
+        @type user: L{str}
+        @param user: The username associated with the connection.
+
+        @type version: L{int}
+        @param version: The SOCKS protocol version number.
+
+        @type code: L{int}
+        @param code: The command code. 1 means establish a TCP/IP stream
+            connection, and 2 means establish a TCP/IP port binding.
+
+        @type port: L{int}
+        @param port: The port number associated with the connection.
+        """
+        assert version == 4, "Bad version code: %s" % version
+        if not self.authorize(code, server, port, user):
+            self.makeReply(91)
+            return
+        if code == 1:  # CONNECT
+            d = self.connectClass(server, port, SOCKSv4Outgoing, self)
+            d.addErrback(lambda result, self=self: self.makeReply(91))
+        elif code == 2:  # BIND
+            d = self.listenClass(0, SOCKSv4IncomingFactory, self, server)
+            d.addCallback(lambda x, self=self: self.makeReply(90, 0, x[1], x[0]))
+        else:
+            raise RuntimeError(f"Bad Connect Code: {code}")
+        assert self.buf == b"", "hmm, still stuff in buffer... %s" % repr(self.buf)
+
+    def connectionLost(self, reason):
+        if self.otherConn:
+            self.otherConn.transport.loseConnection()
+
+    def authorize(self, code, server, port, user):
+        log.msg(
+            "code %s connection to %s:%s (user %s) authorized"
+            % (code, server, port, user)
+        )
+        return 1
+
+    def connectClass(self, host, port, klass, *args):
+        return protocol.ClientCreator(reactor, klass, *args).connectTCP(host, port)
+
+    def listenClass(self, port, klass, *args):
+        serv = reactor.listenTCP(port, klass(*args))
+        return defer.succeed(serv.getHost()[1:])
+
+    def makeReply(self, reply, version=0, port=0, ip="0.0.0.0"):
+        self.transport.write(
+            struct.pack("!BBH", version, reply, port) + socket.inet_aton(ip)
+        )
+        if reply != 90:
+            self.transport.loseConnection()
+
+    def write(self, data):
+        self.log(self, data)
+        self.transport.write(data)
+
+    def log(self, proto, data):
+        if not self.logging:
+            return
+        peer = self.transport.getPeer()
+        their_peer = self.otherConn.transport.getPeer()
+        f = open(self.logging, "a")
+        f.write(
+            "%s\t%s:%d %s %s:%d\n"
+            % (
+                time.ctime(),
+                peer.host,
+                peer.port,
+                ((proto == self and "<") or ">"),
+                their_peer.host,
+                their_peer.port,
+            )
+        )
+        while data:
+            p, data = data[:16], data[16:]
+            f.write(string.join(map(lambda x: "%02X" % ord(x), p), " ") + " ")
+            f.write((16 - len(p)) * 3 * " ")
+            for c in p:
+                if len(repr(c)) > 3:
+                    f.write(".")
+                else:
+                    f.write(c)
+            f.write("\n")
+        f.write("\n")
+        f.close()
+
+
+class SOCKSv4Factory(protocol.Factory):
+    """
+    A factory for a SOCKSv4 proxy.
+
+    Constructor accepts one argument, a log file name.
+    """
+
+    def __init__(self, log):
+        self.logging = log
+
+    def buildProtocol(self, addr):
+        return SOCKSv4(self.logging, reactor)
+
+
+class SOCKSv4IncomingFactory(protocol.Factory):
+    """
+    A utility class for building protocols for incoming connections.
+    """
+
+    def __init__(self, socks, ip):
+        self.socks = socks
+        self.ip = ip
+
+    def buildProtocol(self, addr):
+        if addr[0] == self.ip:
+            self.ip = ""
+            self.socks.makeReply(90, 0)
+            return SOCKSv4Incoming(self.socks)
+        elif self.ip == "":
+            return None
+        else:
+            self.socks.makeReply(91, 0)
+            self.ip = ""
+            return None

backend/lib/python3.12/site-packages/twisted/protocols/stateful.py

@@ -0,0 +1,52 @@
+# -*- test-case-name: twisted.test.test_stateful -*-
+
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+
+from io import BytesIO
+
+from twisted.internet import protocol
+
+
+class StatefulProtocol(protocol.Protocol):
+    """A Protocol that stores state for you.
+
+    state is a pair (function, num_bytes). When num_bytes bytes of data arrives
+    from the network, function is called. It is expected to return the next
+    state or None to keep same state. Initial state is returned by
+    getInitialState (override it).
+    """
+
+    _sful_data = None, None, 0
+
+    def makeConnection(self, transport):
+        protocol.Protocol.makeConnection(self, transport)
+        self._sful_data = self.getInitialState(), BytesIO(), 0
+
+    def getInitialState(self):
+        raise NotImplementedError
+
+    def dataReceived(self, data):
+        state, buffer, offset = self._sful_data
+        buffer.seek(0, 2)
+        buffer.write(data)
+        blen = buffer.tell()  # how many bytes total is in the buffer
+        buffer.seek(offset)
+        while blen - offset >= state[1]:
+            d = buffer.read(state[1])
+            offset += state[1]
+            next = state[0](d)
+            if (
+                self.transport.disconnecting
+            ):  # XXX: argh stupid hack borrowed right from LineReceiver
+                return  # dataReceived won't be called again, so who cares about consistent state
+            if next:
+                state = next
+        if offset != 0:
+            b = buffer.read()
+            buffer.seek(0)
+            buffer.truncate()
+            buffer.write(b)
+            offset = 0
+        self._sful_data = state, buffer, offset

backend/lib/python3.12/site-packages/twisted/protocols/test/__init__.py

@@ -0,0 +1,6 @@
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""
+Unit tests for L{twisted.protocols}.
+"""

backend/lib/python3.12/site-packages/twisted/protocols/tls.py

@@ -0,0 +1,936 @@
+# -*- test-case-name: twisted.protocols.test.test_tls,twisted.internet.test.test_tls,twisted.test.test_sslverify -*-
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""
+Implementation of a TLS transport (L{ISSLTransport}) as an
+L{IProtocol<twisted.internet.interfaces.IProtocol>} layered on top of any
+L{ITransport<twisted.internet.interfaces.ITransport>} implementation, based on
+U{OpenSSL<http://www.openssl.org>}'s memory BIO features.
+
+L{TLSMemoryBIOFactory} is a L{WrappingFactory} which wraps protocols created by
+the factory it wraps with L{TLSMemoryBIOProtocol}.  L{TLSMemoryBIOProtocol}
+intercedes between the underlying transport and the wrapped protocol to
+implement SSL and TLS.  Typical usage of this module looks like this::
+
+    from twisted.protocols.tls import TLSMemoryBIOFactory
+    from twisted.internet.protocol import ServerFactory
+    from twisted.internet.ssl import PrivateCertificate
+    from twisted.internet import reactor
+
+    from someapplication import ApplicationProtocol
+
+    serverFactory = ServerFactory()
+    serverFactory.protocol = ApplicationProtocol
+    certificate = PrivateCertificate.loadPEM(certPEMData)
+    contextFactory = certificate.options()
+    tlsFactory = TLSMemoryBIOFactory(contextFactory, False, serverFactory)
+    reactor.listenTCP(12345, tlsFactory)
+    reactor.run()
+
+This API offers somewhat more flexibility than
+L{twisted.internet.interfaces.IReactorSSL}; for example, a
+L{TLSMemoryBIOProtocol} instance can use another instance of
+L{TLSMemoryBIOProtocol} as its transport, yielding TLS over TLS - useful to
+implement onion routing.  It can also be used to run TLS over unusual
+transports, such as UNIX sockets and stdio.
+"""
+
+from __future__ import annotations
+
+from typing import Callable, Iterable, Optional, cast
+
+from zope.interface import directlyProvides, implementer, providedBy
+
+from OpenSSL.SSL import Connection, Error, SysCallError, WantReadError, ZeroReturnError
+
+from twisted.internet._producer_helpers import _PullToPush
+from twisted.internet._sslverify import _setAcceptableProtocols
+from twisted.internet.interfaces import (
+    IDelayedCall,
+    IHandshakeListener,
+    ILoggingContext,
+    INegotiated,
+    IOpenSSLClientConnectionCreator,
+    IOpenSSLServerConnectionCreator,
+    IProtocol,
+    IProtocolNegotiationFactory,
+    IPushProducer,
+    IReactorTime,
+    ISystemHandle,
+    ITransport,
+)
+from twisted.internet.main import CONNECTION_LOST
+from twisted.internet.protocol import Protocol
+from twisted.protocols.policies import ProtocolWrapper, WrappingFactory
+from twisted.python.failure import Failure
+
+
+@implementer(IPushProducer)
+class _ProducerMembrane:
+    """
+    Stand-in for producer registered with a L{TLSMemoryBIOProtocol} transport.
+
+    Ensures that producer pause/resume events from the undelying transport are
+    coordinated with pause/resume events from the TLS layer.
+
+    @ivar _producer: The application-layer producer.
+    """
+
+    _producerPaused = False
+
+    def __init__(self, producer):
+        self._producer = producer
+
+    def pauseProducing(self):
+        """
+        C{pauseProducing} the underlying producer, if it's not paused.
+        """
+        if self._producerPaused:
+            return
+        self._producerPaused = True
+        self._producer.pauseProducing()
+
+    def resumeProducing(self):
+        """
+        C{resumeProducing} the underlying producer, if it's paused.
+        """
+        if not self._producerPaused:
+            return
+        self._producerPaused = False
+        self._producer.resumeProducing()
+
+    def stopProducing(self):
+        """
+        C{stopProducing} the underlying producer.
+
+        There is only a single source for this event, so it's simply passed
+        on.
+        """
+        self._producer.stopProducing()
+
+
+def _representsEOF(exceptionObject: Error) -> bool:
+    """
+    Does the given OpenSSL.SSL.Error represent an end-of-file?
+    """
+    reasonString: str
+    if isinstance(exceptionObject, SysCallError):
+        _, reasonString = exceptionObject.args
+    else:
+        errorQueue = exceptionObject.args[0]
+        _, _, reasonString = errorQueue[-1]
+    return reasonString.casefold().startswith("unexpected eof")
+
+
+@implementer(ISystemHandle, INegotiated, ITransport)
+class TLSMemoryBIOProtocol(ProtocolWrapper):
+    """
+    L{TLSMemoryBIOProtocol} is a protocol wrapper which uses OpenSSL via a
+    memory BIO to encrypt bytes written to it before sending them on to the
+    underlying transport and decrypts bytes received from the underlying
+    transport before delivering them to the wrapped protocol.
+
+    In addition to producer events from the underlying transport, the need to
+    wait for reads before a write can proceed means the L{TLSMemoryBIOProtocol}
+    may also want to pause a producer.  Pause/resume events are therefore
+    merged using the L{_ProducerMembrane} wrapper.  Non-streaming (pull)
+    producers are supported by wrapping them with L{_PullToPush}.
+
+    Because TLS may need to wait for reads before writing, some writes may be
+    buffered until a read occurs.
+
+    @ivar _tlsConnection: The L{OpenSSL.SSL.Connection} instance which is
+        encrypted and decrypting this connection.
+
+    @ivar _lostTLSConnection: A flag indicating whether connection loss has
+        already been dealt with (C{True}) or not (C{False}).  TLS disconnection
+        is distinct from the underlying connection being lost.
+
+    @ivar _appSendBuffer: application-level (cleartext) data that is waiting to
+        be transferred to the TLS buffer, but can't be because the TLS
+        connection is handshaking.
+    @type _appSendBuffer: L{list} of L{bytes}
+
+    @ivar _connectWrapped: A flag indicating whether or not to call
+        C{makeConnection} on the wrapped protocol.  This is for the reactor's
+        L{twisted.internet.interfaces.ITLSTransport.startTLS} implementation,
+        since it has a protocol which it has already called C{makeConnection}
+        on, and which has no interest in a new transport.  See #3821.
+
+    @ivar _handshakeDone: A flag indicating whether or not the handshake is
+        known to have completed successfully (C{True}) or not (C{False}).  This
+        is used to control error reporting behavior.  If the handshake has not
+        completed, the underlying L{OpenSSL.SSL.Error} will be passed to the
+        application's C{connectionLost} method.  If it has completed, any
+        unexpected L{OpenSSL.SSL.Error} will be turned into a
+        L{ConnectionLost}.  This is weird; however, it is simply an attempt at
+        a faithful re-implementation of the behavior provided by
+        L{twisted.internet.ssl}.
+
+    @ivar _reason: If an unexpected L{OpenSSL.SSL.Error} occurs which causes
+        the connection to be lost, it is saved here.  If appropriate, this may
+        be used as the reason passed to the application protocol's
+        C{connectionLost} method.
+
+    @ivar _producer: The current producer registered via C{registerProducer},
+        or L{None} if no producer has been registered or a previous one was
+        unregistered.
+
+    @ivar _aborted: C{abortConnection} has been called.  No further data will
+        be received to the wrapped protocol's C{dataReceived}.
+    @type _aborted: L{bool}
+    """
+
+    _reason = None
+    _handshakeDone = False
+    _lostTLSConnection = False
+    _producer = None
+    _aborted = False
+
+    def __init__(self, factory, wrappedProtocol, _connectWrapped=True):
+        ProtocolWrapper.__init__(self, factory, wrappedProtocol)
+        self._connectWrapped = _connectWrapped
+
+    def getHandle(self):
+        """
+        Return the L{OpenSSL.SSL.Connection} object being used to encrypt and
+        decrypt this connection.
+
+        This is done for the benefit of L{twisted.internet.ssl.Certificate}'s
+        C{peerFromTransport} and C{hostFromTransport} methods only.  A
+        different system handle may be returned by future versions of this
+        method.
+        """
+        return self._tlsConnection
+
+    def makeConnection(self, transport):
+        """
+        Connect this wrapper to the given transport and initialize the
+        necessary L{OpenSSL.SSL.Connection} with a memory BIO.
+        """
+        self._tlsConnection = self.factory._createConnection(self)
+        self._appSendBuffer = []
+
+        # Add interfaces provided by the transport we are wrapping:
+        for interface in providedBy(transport):
+            directlyProvides(self, interface)
+
+        # Intentionally skip ProtocolWrapper.makeConnection - it might call
+        # wrappedProtocol.makeConnection, which we want to make conditional.
+        Protocol.makeConnection(self, transport)
+        self.factory.registerProtocol(self)
+        if self._connectWrapped:
+            # Now that the TLS layer is initialized, notify the application of
+            # the connection.
+            ProtocolWrapper.makeConnection(self, transport)
+
+        # Now that we ourselves have a transport (initialized by the
+        # ProtocolWrapper.makeConnection call above), kick off the TLS
+        # handshake.
+        self._checkHandshakeStatus()
+
+    def _checkHandshakeStatus(self):
+        """
+        Ask OpenSSL to proceed with a handshake in progress.
+
+        Initially, this just sends the ClientHello; after some bytes have been
+        stuffed in to the C{Connection} object by C{dataReceived}, it will then
+        respond to any C{Certificate} or C{KeyExchange} messages.
+        """
+        # The connection might already be aborted (eg. by a callback during
+        # connection setup), so don't even bother trying to handshake in that
+        # case.
+        if self._aborted:
+            return
+        try:
+            self._tlsConnection.do_handshake()
+        except WantReadError:
+            self._flushSendBIO()
+        except Error:
+            self._tlsShutdownFinished(Failure())
+        else:
+            self._handshakeDone = True
+            if IHandshakeListener.providedBy(self.wrappedProtocol):
+                self.wrappedProtocol.handshakeCompleted()
+
+    def _flushSendBIO(self):
+        """
+        Read any bytes out of the send BIO and write them to the underlying
+        transport.
+        """
+        try:
+            bytes = self._tlsConnection.bio_read(2**15)
+        except WantReadError:
+            # There may be nothing in the send BIO right now.
+            pass
+        else:
+            self.transport.write(bytes)
+
+    def _flushReceiveBIO(self):
+        """
+        Try to receive any application-level bytes which are now available
+        because of a previous write into the receive BIO.  This will take
+        care of delivering any application-level bytes which are received to
+        the protocol, as well as handling of the various exceptions which
+        can come from trying to get such bytes.
+        """
+        # Keep trying this until an error indicates we should stop or we
+        # close the connection.  Looping is necessary to make sure we
+        # process all of the data which was put into the receive BIO, as
+        # there is no guarantee that a single recv call will do it all.
+        while not self._lostTLSConnection:
+            try:
+                bytes = self._tlsConnection.recv(2**15)
+            except WantReadError:
+                # The newly received bytes might not have been enough to produce
+                # any application data.
+                break
+            except ZeroReturnError:
+                # TLS has shut down and no more TLS data will be received over
+                # this connection.
+                self._shutdownTLS()
+                # Passing in None means the user protocol's connnectionLost
+                # will get called with reason from underlying transport:
+                self._tlsShutdownFinished(None)
+            except Error:
+                # Something went pretty wrong.  For example, this might be a
+                # handshake failure during renegotiation (because there were no
+                # shared ciphers, because a certificate failed to verify, etc).
+                # TLS can no longer proceed.
+                failure = Failure()
+                self._tlsShutdownFinished(failure)
+            else:
+                if not self._aborted:
+                    ProtocolWrapper.dataReceived(self, bytes)
+
+        # The received bytes might have generated a response which needs to be
+        # sent now.  For example, the handshake involves several round-trip
+        # exchanges without ever producing application-bytes.
+        self._flushSendBIO()
+
+    def dataReceived(self, bytes):
+        """
+        Deliver any received bytes to the receive BIO and then read and deliver
+        to the application any application-level data which becomes available
+        as a result of this.
+        """
+        # Let OpenSSL know some bytes were just received.
+        self._tlsConnection.bio_write(bytes)
+
+        # If we are still waiting for the handshake to complete, try to
+        # complete the handshake with the bytes we just received.
+        if not self._handshakeDone:
+            self._checkHandshakeStatus()
+
+            # If the handshake still isn't finished, then we've nothing left to
+            # do.
+            if not self._handshakeDone:
+                return
+
+        # If we've any pending writes, this read may have un-blocked them, so
+        # attempt to unbuffer them into the OpenSSL layer.
+        if self._appSendBuffer:
+            self._unbufferPendingWrites()
+
+        # Since the handshake is complete, the wire-level bytes we just
+        # processed might turn into some application-level bytes; try to pull
+        # those out.
+        self._flushReceiveBIO()
+
+    def _shutdownTLS(self):
+        """
+        Initiate, or reply to, the shutdown handshake of the TLS layer.
+        """
+        try:
+            shutdownSuccess = self._tlsConnection.shutdown()
+        except Error:
+            # Mid-handshake, a call to shutdown() can result in a
+            # WantWantReadError, or rather an SSL_ERR_WANT_READ; but pyOpenSSL
+            # doesn't allow us to get at the error.  See:
+            # https://github.com/pyca/pyopenssl/issues/91
+            shutdownSuccess = False
+        self._flushSendBIO()
+        if shutdownSuccess:
+            # Both sides have shutdown, so we can start closing lower-level
+            # transport. This will also happen if we haven't started
+            # negotiation at all yet, in which case shutdown succeeds
+            # immediately.
+            self.transport.loseConnection()
+
+    def _tlsShutdownFinished(self, reason):
+        """
+        Called when TLS connection has gone away; tell underlying transport to
+        disconnect.
+
+        @param reason: a L{Failure} whose value is an L{Exception} if we want to
+            report that failure through to the wrapped protocol's
+            C{connectionLost}, or L{None} if the C{reason} that
+            C{connectionLost} should receive should be coming from the
+            underlying transport.
+        @type reason: L{Failure} or L{None}
+        """
+        if reason is not None:
+            # Squash an EOF in violation of the TLS protocol into
+            # ConnectionLost, so that applications which might run over
+            # multiple protocols can recognize its type.
+            if _representsEOF(reason.value):
+                reason = Failure(CONNECTION_LOST)
+        if self._reason is None:
+            self._reason = reason
+        self._lostTLSConnection = True
+        # We may need to send a TLS alert regarding the nature of the shutdown
+        # here (for example, why a handshake failed), so always flush our send
+        # buffer before telling our lower-level transport to go away.
+        self._flushSendBIO()
+        # Using loseConnection causes the application protocol's
+        # connectionLost method to be invoked non-reentrantly, which is always
+        # a nice feature. However, for error cases (reason != None) we might
+        # want to use abortConnection when it becomes available. The
+        # loseConnection call is basically tested by test_handshakeFailure.
+        # At least one side will need to do it or the test never finishes.
+        self.transport.loseConnection()
+
+    def connectionLost(self, reason):
+        """
+        Handle the possible repetition of calls to this method (due to either
+        the underlying transport going away or due to an error at the TLS
+        layer) and make sure the base implementation only gets invoked once.
+        """
+        if not self._lostTLSConnection:
+            # Tell the TLS connection that it's not going to get any more data
+            # and give it a chance to finish reading.
+            self._tlsConnection.bio_shutdown()
+            self._flushReceiveBIO()
+            self._lostTLSConnection = True
+        reason = self._reason or reason
+        self._reason = None
+        self.connected = False
+        ProtocolWrapper.connectionLost(self, reason)
+
+        # Breaking reference cycle between self._tlsConnection and self.
+        self._tlsConnection = None
+
+    def loseConnection(self):
+        """
+        Send a TLS close alert and close the underlying connection.
+        """
+        if self.disconnecting or not self.connected:
+            return
+        # If connection setup has not finished, OpenSSL 1.0.2f+ will not shut
+        # down the connection until we write some data to the connection which
+        # allows the handshake to complete. However, since no data should be
+        # written after loseConnection, this means we'll be stuck forever
+        # waiting for shutdown to complete. Instead, we simply abort the
+        # connection without trying to shut down cleanly:
+        if not self._handshakeDone and not self._appSendBuffer:
+            self.abortConnection()
+        self.disconnecting = True
+        if not self._appSendBuffer and self._producer is None:
+            self._shutdownTLS()
+
+    def abortConnection(self):
+        """
+        Tear down TLS state so that if the connection is aborted mid-handshake
+        we don't deliver any further data from the application.
+        """
+        self._aborted = True
+        self.disconnecting = True
+        self._shutdownTLS()
+        self.transport.abortConnection()
+
+    def failVerification(self, reason):
+        """
+        Abort the connection during connection setup, giving a reason that
+        certificate verification failed.
+
+        @param reason: The reason that the verification failed; reported to the
+            application protocol's C{connectionLost} method.
+        @type reason: L{Failure}
+        """
+        self._reason = reason
+        self.abortConnection()
+
+    def write(self, bytes):
+        """
+        Process the given application bytes and send any resulting TLS traffic
+        which arrives in the send BIO.
+
+        If C{loseConnection} was called, subsequent calls to C{write} will
+        drop the bytes on the floor.
+        """
+        # Writes after loseConnection are not supported, unless a producer has
+        # been registered, in which case writes can happen until the producer
+        # is unregistered:
+        if self.disconnecting and self._producer is None:
+            return
+        self._write(bytes)
+
+    def _bufferedWrite(self, octets):
+        """
+        Put the given octets into L{TLSMemoryBIOProtocol._appSendBuffer}, and
+        tell any listening producer that it should pause because we are now
+        buffering.
+        """
+        self._appSendBuffer.append(octets)
+        if self._producer is not None:
+            self._producer.pauseProducing()
+
+    def _unbufferPendingWrites(self):
+        """
+        Un-buffer all waiting writes in L{TLSMemoryBIOProtocol._appSendBuffer}.
+        """
+        pendingWrites, self._appSendBuffer = self._appSendBuffer, []
+        for eachWrite in pendingWrites:
+            self._write(eachWrite)
+
+        if self._appSendBuffer:
+            # If OpenSSL ran out of buffer space in the Connection on our way
+            # through the loop earlier and re-buffered any of our outgoing
+            # writes, then we're done; don't consider any future work.
+            return
+
+        if self._producer is not None:
+            # If we have a registered producer, let it know that we have some
+            # more buffer space.
+            self._producer.resumeProducing()
+            return
+
+        if self.disconnecting:
+            # Finally, if we have no further buffered data, no producer wants
+            # to send us more data in the future, and the application told us
+            # to end the stream, initiate a TLS shutdown.
+            self._shutdownTLS()
+
+    def _write(self, bytes):
+        """
+        Process the given application bytes and send any resulting TLS traffic
+        which arrives in the send BIO.
+
+        This may be called by C{dataReceived} with bytes that were buffered
+        before C{loseConnection} was called, which is why this function
+        doesn't check for disconnection but accepts the bytes regardless.
+        """
+        if self._lostTLSConnection:
+            return
+
+        # A TLS payload is 16kB max
+        bufferSize = 2**14
+
+        # How far into the input we've gotten so far
+        alreadySent = 0
+
+        while alreadySent < len(bytes):
+            toSend = bytes[alreadySent : alreadySent + bufferSize]
+            try:
+                sent = self._tlsConnection.send(toSend)
+            except WantReadError:
+                self._bufferedWrite(bytes[alreadySent:])
+                break
+            except Error:
+                # Pretend TLS connection disconnected, which will trigger
+                # disconnect of underlying transport. The error will be passed
+                # to the application protocol's connectionLost method.  The
+                # other SSL implementation doesn't, but losing helpful
+                # debugging information is a bad idea.
+                self._tlsShutdownFinished(Failure())
+                break
+            else:
+                # We've successfully handed off the bytes to the OpenSSL
+                # Connection object.
+                alreadySent += sent
+                # See if OpenSSL wants to hand any bytes off to the underlying
+                # transport as a result.
+                self._flushSendBIO()
+
+    def writeSequence(self, iovec):
+        """
+        Write a sequence of application bytes by joining them into one string
+        and passing them to L{write}.
+        """
+        self.write(b"".join(iovec))
+
+    def getPeerCertificate(self):
+        return self._tlsConnection.get_peer_certificate()
+
+    @property
+    def negotiatedProtocol(self):
+        """
+        @see: L{INegotiated.negotiatedProtocol}
+        """
+        protocolName = None
+
+        try:
+            # If ALPN is not implemented that's ok, NPN might be.
+            protocolName = self._tlsConnection.get_alpn_proto_negotiated()
+        except (NotImplementedError, AttributeError):
+            pass
+
+        if protocolName not in (b"", None):
+            # A protocol was selected using ALPN.
+            return protocolName
+
+        try:
+            protocolName = self._tlsConnection.get_next_proto_negotiated()
+        except (NotImplementedError, AttributeError):
+            pass
+
+        if protocolName != b"":
+            return protocolName
+
+        return None
+
+    def registerProducer(self, producer, streaming):
+        # If we've already disconnected, nothing to do here:
+        if self._lostTLSConnection:
+            producer.stopProducing()
+            return
+
+        # If we received a non-streaming producer, wrap it so it becomes a
+        # streaming producer:
+        if not streaming:
+            producer = streamingProducer = _PullToPush(producer, self)
+        producer = _ProducerMembrane(producer)
+        # This will raise an exception if a producer is already registered:
+        self.transport.registerProducer(producer, True)
+        self._producer = producer
+        # If we received a non-streaming producer, we need to start the
+        # streaming wrapper:
+        if not streaming:
+            streamingProducer.startStreaming()
+
+    def unregisterProducer(self):
+        # If we have no producer, we don't need to do anything here.
+        if self._producer is None:
+            return
+
+        # If we received a non-streaming producer, we need to stop the
+        # streaming wrapper:
+        if isinstance(self._producer._producer, _PullToPush):
+            self._producer._producer.stopStreaming()
+        self._producer = None
+        self._producerPaused = False
+        self.transport.unregisterProducer()
+        if self.disconnecting and not self._appSendBuffer:
+            self._shutdownTLS()
+
+
+@implementer(IOpenSSLClientConnectionCreator, IOpenSSLServerConnectionCreator)
+class _ContextFactoryToConnectionFactory:
+    """
+    Adapter wrapping a L{twisted.internet.interfaces.IOpenSSLContextFactory}
+    into a L{IOpenSSLClientConnectionCreator} or
+    L{IOpenSSLServerConnectionCreator}.
+
+    See U{https://twistedmatrix.com/trac/ticket/7215} for work that should make
+    this unnecessary.
+    """
+
+    def __init__(self, oldStyleContextFactory):
+        """
+        Construct a L{_ContextFactoryToConnectionFactory} with a
+        L{twisted.internet.interfaces.IOpenSSLContextFactory}.
+
+        Immediately call C{getContext} on C{oldStyleContextFactory} in order to
+        force advance parameter checking, since old-style context factories
+        don't actually check that their arguments to L{OpenSSL} are correct.
+
+        @param oldStyleContextFactory: A factory that can produce contexts.
+        @type oldStyleContextFactory:
+            L{twisted.internet.interfaces.IOpenSSLContextFactory}
+        """
+        oldStyleContextFactory.getContext()
+        self._oldStyleContextFactory = oldStyleContextFactory
+
+    def _connectionForTLS(self, protocol):
+        """
+        Create an L{OpenSSL.SSL.Connection} object.
+
+        @param protocol: The protocol initiating a TLS connection.
+        @type protocol: L{TLSMemoryBIOProtocol}
+
+        @return: a connection
+        @rtype: L{OpenSSL.SSL.Connection}
+        """
+        context = self._oldStyleContextFactory.getContext()
+        return Connection(context, None)
+
+    def serverConnectionForTLS(self, protocol):
+        """
+        Construct an OpenSSL server connection from the wrapped old-style
+        context factory.
+
+        @note: Since old-style context factories don't distinguish between
+            clients and servers, this is exactly the same as
+            L{_ContextFactoryToConnectionFactory.clientConnectionForTLS}.
+
+        @param protocol: The protocol initiating a TLS connection.
+        @type protocol: L{TLSMemoryBIOProtocol}
+
+        @return: a connection
+        @rtype: L{OpenSSL.SSL.Connection}
+        """
+        return self._connectionForTLS(protocol)
+
+    def clientConnectionForTLS(self, protocol):
+        """
+        Construct an OpenSSL server connection from the wrapped old-style
+        context factory.
+
+        @note: Since old-style context factories don't distinguish between
+            clients and servers, this is exactly the same as
+            L{_ContextFactoryToConnectionFactory.serverConnectionForTLS}.
+
+        @param protocol: The protocol initiating a TLS connection.
+        @type protocol: L{TLSMemoryBIOProtocol}
+
+        @return: a connection
+        @rtype: L{OpenSSL.SSL.Connection}
+        """
+        return self._connectionForTLS(protocol)
+
+
+class _AggregateSmallWrites:
+    """
+    Aggregate small writes so they get written in large batches.
+
+    If this is used as part of a transport, the transport needs to call
+    ``flush()`` immediately when ``loseConnection()`` is called, otherwise any
+    buffered writes will never get written.
+
+    @cvar MAX_BUFFER_SIZE: The maximum amount of bytes to buffer before writing
+        them out.
+    """
+
+    MAX_BUFFER_SIZE = 64_000
+
+    def __init__(self, write: Callable[[bytes], object], clock: IReactorTime):
+        self._write = write
+        self._clock = clock
+        self._buffer: list[bytes] = []
+        self._bufferLeft = self.MAX_BUFFER_SIZE
+        self._scheduled: Optional[IDelayedCall] = None
+
+    def write(self, data: bytes) -> None:
+        """
+        Buffer the data, or write it immediately if we've accumulated enough to
+        make it worth it.
+
+        Accumulating too much data can result in higher memory usage.
+        """
+        self._buffer.append(data)
+        self._bufferLeft -= len(data)
+
+        if self._bufferLeft < 0:
+            # We've accumulated enough we should just write it out. No need to
+            # schedule a flush, since we just flushed everything.
+            self.flush()
+            return
+
+        if self._scheduled:
+            # We already have a scheduled send, so with the data in the buffer,
+            # there is nothing more to do here.
+            return
+
+        # Schedule the write of the accumulated buffer for the next reactor
+        # iteration.
+        self._scheduled = self._clock.callLater(0, self._scheduledFlush)
+
+    def _scheduledFlush(self) -> None:
+        """Called in next reactor iteration."""
+        self._scheduled = None
+        self.flush()
+
+    def flush(self) -> None:
+        """Flush any buffered writes."""
+        if self._buffer:
+            self._bufferLeft = self.MAX_BUFFER_SIZE
+            self._write(b"".join(self._buffer))
+            del self._buffer[:]
+
+
+def _get_default_clock() -> IReactorTime:
+    """
+    Return the default reactor.
+
+    This is a function so it can be monkey-patched in tests, specifically
+    L{twisted.web.test.test_agent}.
+    """
+    from twisted.internet import reactor
+
+    return cast(IReactorTime, reactor)
+
+
+class BufferingTLSTransport(TLSMemoryBIOProtocol):
+    """
+    A TLS transport implemented by wrapping buffering around a
+    L{TLSMemoryBIOProtocol}.
+
+    Doing many small writes directly to a L{OpenSSL.SSL.Connection}, as
+    implemented in L{TLSMemoryBIOProtocol}, can add significant CPU and
+    bandwidth overhead.  Thus, even when writing is possible, small writes will
+    get aggregated and written as a single write at the next reactor iteration.
+    """
+
+    # Implementation Note: An implementation based on composition would be
+    # nicer, but there's close integration between L{ProtocolWrapper}
+    # subclasses like L{TLSMemoryBIOProtocol} and the corresponding factory. An
+    # attempt to implement this with broke things like
+    # L{TLSMemoryBIOFactory.protocols} having the correct instances, whereas
+    # subclassing makes that work.
+
+    def __init__(
+        self,
+        factory: TLSMemoryBIOFactory,
+        wrappedProtocol: IProtocol,
+        _connectWrapped: bool = True,
+    ):
+        super().__init__(factory, wrappedProtocol, _connectWrapped)
+        actual_write = super().write
+        self._aggregator = _AggregateSmallWrites(actual_write, factory._clock)
+        # This is kinda ugly, but speeds things up a lot in a hot path with
+        # lots of small TLS writes. May become unnecessary in Python 3.13 or
+        # later if JIT and/or inlining becomes a thing.
+        self.write = self._aggregator.write  # type: ignore[method-assign]
+
+    def writeSequence(self, sequence: Iterable[bytes]) -> None:
+        self._aggregator.write(b"".join(sequence))
+
+    def loseConnection(self) -> None:
+        self._aggregator.flush()
+        super().loseConnection()
+
+
+class TLSMemoryBIOFactory(WrappingFactory):
+    """
+    L{TLSMemoryBIOFactory} adds TLS to connections.
+
+    @ivar _creatorInterface: the interface which L{_connectionCreator} is
+        expected to implement.
+    @type _creatorInterface: L{zope.interface.interfaces.IInterface}
+
+    @ivar _connectionCreator: a callable which creates an OpenSSL Connection
+        object.
+    @type _connectionCreator: 1-argument callable taking
+        L{TLSMemoryBIOProtocol} and returning L{OpenSSL.SSL.Connection}.
+    """
+
+    protocol = BufferingTLSTransport
+
+    noisy = False  # disable unnecessary logging.
+
+    def __init__(
+        self,
+        contextFactory,
+        isClient,
+        wrappedFactory,
+        clock=None,
+    ):
+        """
+        Create a L{TLSMemoryBIOFactory}.
+
+        @param contextFactory: Configuration parameters used to create an
+            OpenSSL connection.  In order of preference, what you should pass
+            here should be:
+
+                1. L{twisted.internet.ssl.CertificateOptions} (if you're
+                   writing a server) or the result of
+                   L{twisted.internet.ssl.optionsForClientTLS} (if you're
+                   writing a client).  If you want security you should really
+                   use one of these.
+
+                2. If you really want to implement something yourself, supply a
+                   provider of L{IOpenSSLClientConnectionCreator} or
+                   L{IOpenSSLServerConnectionCreator}.
+
+                3. If you really have to, supply a
+                   L{twisted.internet.ssl.ContextFactory}.  This will likely be
+                   deprecated at some point so please upgrade to the new
+                   interfaces.
+
+        @type contextFactory: L{IOpenSSLClientConnectionCreator} or
+            L{IOpenSSLServerConnectionCreator}, or, for compatibility with
+            older code, anything implementing
+            L{twisted.internet.interfaces.IOpenSSLContextFactory}.  See
+            U{https://twistedmatrix.com/trac/ticket/7215} for information on
+            the upcoming deprecation of passing a
+            L{twisted.internet.ssl.ContextFactory} here.
+
+        @param isClient: Is this a factory for TLS client connections; in other
+            words, those that will send a C{ClientHello} greeting?  L{True} if
+            so, L{False} otherwise.  This flag determines what interface is
+            expected of C{contextFactory}.  If L{True}, C{contextFactory}
+            should provide L{IOpenSSLClientConnectionCreator}; otherwise it
+            should provide L{IOpenSSLServerConnectionCreator}.
+        @type isClient: L{bool}
+
+        @param wrappedFactory: A factory which will create the
+            application-level protocol.
+        @type wrappedFactory: L{twisted.internet.interfaces.IProtocolFactory}
+        """
+        WrappingFactory.__init__(self, wrappedFactory)
+        if isClient:
+            creatorInterface = IOpenSSLClientConnectionCreator
+        else:
+            creatorInterface = IOpenSSLServerConnectionCreator
+        self._creatorInterface = creatorInterface
+        if not creatorInterface.providedBy(contextFactory):
+            contextFactory = _ContextFactoryToConnectionFactory(contextFactory)
+        self._connectionCreator = contextFactory
+
+        if clock is None:
+            clock = _get_default_clock()
+        self._clock = clock
+
+    def logPrefix(self):
+        """
+        Annotate the wrapped factory's log prefix with some text indicating TLS
+        is in use.
+
+        @rtype: C{str}
+        """
+        if ILoggingContext.providedBy(self.wrappedFactory):
+            logPrefix = self.wrappedFactory.logPrefix()
+        else:
+            logPrefix = self.wrappedFactory.__class__.__name__
+        return f"{logPrefix} (TLS)"
+
+    def _applyProtocolNegotiation(self, connection):
+        """
+        Applies ALPN/NPN protocol neogitation to the connection, if the factory
+        supports it.
+
+        @param connection: The OpenSSL connection object to have ALPN/NPN added
+            to it.
+        @type connection: L{OpenSSL.SSL.Connection}
+
+        @return: Nothing
+        @rtype: L{None}
+        """
+        if IProtocolNegotiationFactory.providedBy(self.wrappedFactory):
+            protocols = self.wrappedFactory.acceptableProtocols()
+            context = connection.get_context()
+            _setAcceptableProtocols(context, protocols)
+
+        return
+
+    def _createConnection(self, tlsProtocol):
+        """
+        Create an OpenSSL connection and set it up good.
+
+        @param tlsProtocol: The protocol which is establishing the connection.
+        @type tlsProtocol: L{TLSMemoryBIOProtocol}
+
+        @return: an OpenSSL connection object for C{tlsProtocol} to use
+        @rtype: L{OpenSSL.SSL.Connection}
+        """
+        connectionCreator = self._connectionCreator
+        if self._creatorInterface is IOpenSSLClientConnectionCreator:
+            connection = connectionCreator.clientConnectionForTLS(tlsProtocol)
+            self._applyProtocolNegotiation(connection)
+            connection.set_connect_state()
+        else:
+            connection = connectionCreator.serverConnectionForTLS(tlsProtocol)
+            self._applyProtocolNegotiation(connection)
+            connection.set_accept_state()
+        return connection

backend/lib/python3.12/site-packages/twisted/protocols/wire.py

@@ -0,0 +1,112 @@
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""Implement standard (and unused) TCP protocols.
+
+These protocols are either provided by inetd, or are not provided at all.
+"""
+
+
+import struct
+import time
+
+from zope.interface import implementer
+
+from twisted.internet import interfaces, protocol
+
+
+class Echo(protocol.Protocol):
+    """
+    As soon as any data is received, write it back (RFC 862).
+    """
+
+    def dataReceived(self, data):
+        self.transport.write(data)
+
+
+class Discard(protocol.Protocol):
+    """
+    Discard any received data (RFC 863).
+    """
+
+    def dataReceived(self, data):
+        # I'm ignoring you, nyah-nyah
+        pass
+
+
+@implementer(interfaces.IProducer)
+class Chargen(protocol.Protocol):
+    """
+    Generate repeating noise (RFC 864).
+    """
+
+    noise = rb'@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~ !"#$%&?'
+
+    def connectionMade(self):
+        self.transport.registerProducer(self, 0)
+
+    def resumeProducing(self):
+        self.transport.write(self.noise)
+
+    def pauseProducing(self):
+        pass
+
+    def stopProducing(self):
+        pass
+
+
+class QOTD(protocol.Protocol):
+    """
+    Return a quote of the day (RFC 865).
+    """
+
+    def connectionMade(self):
+        self.transport.write(self.getQuote())
+        self.transport.loseConnection()
+
+    def getQuote(self):
+        """
+        Return a quote. May be overrriden in subclasses.
+        """
+        return b"An apple a day keeps the doctor away.\r\n"
+
+
+class Who(protocol.Protocol):
+    """
+    Return list of active users (RFC 866)
+    """
+
+    def connectionMade(self):
+        self.transport.write(self.getUsers())
+        self.transport.loseConnection()
+
+    def getUsers(self):
+        """
+        Return active users. Override in subclasses.
+        """
+        return b"root\r\n"
+
+
+class Daytime(protocol.Protocol):
+    """
+    Send back the daytime in ASCII form (RFC 867).
+    """
+
+    def connectionMade(self):
+        self.transport.write(time.asctime(time.gmtime(time.time())) + b"\r\n")
+        self.transport.loseConnection()
+
+
+class Time(protocol.Protocol):
+    """
+    Send back the time in machine readable form (RFC 868).
+    """
+
+    def connectionMade(self):
+        # is this correct only for 32-bit machines?
+        result = struct.pack("!i", int(time.time()))
+        self.transport.write(result)
+        self.transport.loseConnection()
+
+
+__all__ = ["Echo", "Discard", "Chargen", "QOTD", "Who", "Daytime", "Time"]