The Tor Browser: testing/mochitest/pywebsocket/mod_pywebsocket/handshake/hybi00.py@b8a032363ba2 (annotated)

testing/mochitest/pywebsocket/mod_pywebsocket/handshake/hybi00.py@b8a032363ba2 (annotated)

testing/mochitest/pywebsocket/mod_pywebsocket/handshake/hybi00.py

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 # Copyright 2011, Google Inc.
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 # copyright notice, this list of conditions and the following disclaimer
 # in the documentation and/or other materials provided with the
 # distribution.
 #     * Neither the name of Google Inc. nor the names of its
 # contributors may be used to endorse or promote products derived from
 # this software without specific prior written permission.
 #
 # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 # A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 # OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 """This file provides the opening handshake processor for the WebSocket
 protocol version HyBi 00.
 Specification:
 http://tools.ietf.org/html/draft-ietf-hybi-thewebsocketprotocol-00
 """
 # Note: request.connection.write/read are used in this module, even though
 # mod_python document says that they should be used only in connection
 # handlers. Unfortunately, we have no other options. For example,
 # request.write/read are not suitable because they don't allow direct raw bytes
 # writing/reading.
 import logging
 import re
 import struct
 from mod_pywebsocket import common
 from mod_pywebsocket.stream import StreamHixie75
 from mod_pywebsocket import util
 from mod_pywebsocket.handshake._base import HandshakeException
 from mod_pywebsocket.handshake._base import build_location
 from mod_pywebsocket.handshake._base import check_header_lines
 from mod_pywebsocket.handshake._base import format_header
 from mod_pywebsocket.handshake._base import get_mandatory_header
 from mod_pywebsocket.handshake._base import validate_subprotocol
 _MANDATORY_HEADERS = [
     # key, expected value or None
     [common.UPGRADE_HEADER, common.WEBSOCKET_UPGRADE_TYPE_HIXIE75],
     [common.CONNECTION_HEADER, common.UPGRADE_CONNECTION_TYPE],
 ]
 class Handshaker(object):
     """Opening handshake processor for the WebSocket protocol version HyBi 00.
     """
     def __init__(self, request, dispatcher):
         """Construct an instance.
         Args:
             request: mod_python request.
             dispatcher: Dispatcher (dispatch.Dispatcher).
         Handshaker will add attributes such as ws_resource in performing
         handshake.
         """
         self._logger = util.get_class_logger(self)
         self._request = request
         self._dispatcher = dispatcher
     def do_handshake(self):
         """Perform WebSocket Handshake.
         On _request, we set
             ws_resource, ws_protocol, ws_location, ws_origin, ws_challenge,
             ws_challenge_md5: WebSocket handshake information.
             ws_stream: Frame generation/parsing class.
             ws_version: Protocol version.
         Raises:
             HandshakeException: when any error happened in parsing the opening
                                 handshake request.
         """
         # 5.1 Reading the client's opening handshake.
         # dispatcher sets it in self._request.
         check_header_lines(self._request, _MANDATORY_HEADERS)
         self._set_resource()
         self._set_subprotocol()
         self._set_location()
         self._set_origin()
         self._set_challenge_response()
         self._set_protocol_version()
         self._dispatcher.do_extra_handshake(self._request)
         self._send_handshake()
     def _set_resource(self):
         self._request.ws_resource = self._request.uri
     def _set_subprotocol(self):
         # |Sec-WebSocket-Protocol|
         subprotocol = self._request.headers_in.get(
             common.SEC_WEBSOCKET_PROTOCOL_HEADER)
         if subprotocol is not None:
             validate_subprotocol(subprotocol, hixie=True)
         self._request.ws_protocol = subprotocol
     def _set_location(self):
         # |Host|
         host = self._request.headers_in.get(common.HOST_HEADER)
         if host is not None:
             self._request.ws_location = build_location(self._request)
         # TODO(ukai): check host is this host.
     def _set_origin(self):
         # |Origin|
         origin = self._request.headers_in.get(common.ORIGIN_HEADER)
         if origin is not None:
             self._request.ws_origin = origin
     def _set_protocol_version(self):
         # |Sec-WebSocket-Draft|
         draft = self._request.headers_in.get(common.SEC_WEBSOCKET_DRAFT_HEADER)
         if draft is not None and draft != '0':
             raise HandshakeException('Illegal value for %s: %s' %
                                      (common.SEC_WEBSOCKET_DRAFT_HEADER,
                                       draft))
         self._logger.debug('Protocol version is HyBi 00')
         self._request.ws_version = common.VERSION_HYBI00
         self._request.ws_stream = StreamHixie75(self._request, True)
     def _set_challenge_response(self):
         # 5.2 4-8.
         self._request.ws_challenge = self._get_challenge()
         # 5.2 9. let /response/ be the MD5 finterprint of /challenge/
         self._request.ws_challenge_md5 = util.md5_hash(
             self._request.ws_challenge).digest()
         self._logger.debug(
             'Challenge: %r (%s)',
             self._request.ws_challenge,
             util.hexify(self._request.ws_challenge))
         self._logger.debug(
             'Challenge response: %r (%s)',
             self._request.ws_challenge_md5,
             util.hexify(self._request.ws_challenge_md5))
     def _get_key_value(self, key_field):
         key_value = get_mandatory_header(self._request, key_field)
         self._logger.debug('%s: %r', key_field, key_value)
         # 5.2 4. let /key-number_n/ be the digits (characters in the range
         # U+0030 DIGIT ZERO (0) to U+0039 DIGIT NINE (9)) in /key_n/,
         # interpreted as a base ten integer, ignoring all other characters
         # in /key_n/.
         try:
             key_number = int(re.sub("\\D", "", key_value))
         except:
             raise HandshakeException('%s field contains no digit' % key_field)
         # 5.2 5. let /spaces_n/ be the number of U+0020 SPACE characters
         # in /key_n/.
         spaces = re.subn(" ", "", key_value)[1]
         if spaces == 0:
             raise HandshakeException('%s field contains no space' % key_field)
         self._logger.debug(
             '%s: Key-number is %d and number of spaces is %d',
             key_field, key_number, spaces)
         # 5.2 6. if /key-number_n/ is not an integral multiple of /spaces_n/
         # then abort the WebSocket connection.
         if key_number % spaces != 0:
             raise HandshakeException(
                 '%s: Key-number (%d) is not an integral multiple of spaces '
                 '(%d)' % (key_field, key_number, spaces))
         # 5.2 7. let /part_n/ be /key-number_n/ divided by /spaces_n/.
         part = key_number / spaces
         self._logger.debug('%s: Part is %d', key_field, part)
         return part
     def _get_challenge(self):
         # 5.2 4-7.
         key1 = self._get_key_value(common.SEC_WEBSOCKET_KEY1_HEADER)
         key2 = self._get_key_value(common.SEC_WEBSOCKET_KEY2_HEADER)
         # 5.2 8. let /challenge/ be the concatenation of /part_1/,
         challenge = ''
         challenge += struct.pack('!I', key1)  # network byteorder int
         challenge += struct.pack('!I', key2)  # network byteorder int
         challenge += self._request.connection.read(8)
         return challenge
     def _send_handshake(self):
         response = []
         # 5.2 10. send the following line.
         response.append('HTTP/1.1 101 WebSocket Protocol Handshake\r\n')
         # 5.2 11. send the following fields to the client.
         response.append(format_header(
             common.UPGRADE_HEADER, common.WEBSOCKET_UPGRADE_TYPE_HIXIE75))
         response.append(format_header(
             common.CONNECTION_HEADER, common.UPGRADE_CONNECTION_TYPE))
         response.append(format_header(
             common.SEC_WEBSOCKET_LOCATION_HEADER, self._request.ws_location))
         response.append(format_header(
             common.SEC_WEBSOCKET_ORIGIN_HEADER, self._request.ws_origin))
         if self._request.ws_protocol:
             response.append(format_header(
                 common.SEC_WEBSOCKET_PROTOCOL_HEADER,
                 self._request.ws_protocol))
         # 5.2 12. send two bytes 0x0D 0x0A.
         response.append('\r\n')
         # 5.2 13. send /response/
         response.append(self._request.ws_challenge_md5)
         raw_response = ''.join(response)
         self._request.connection.write(raw_response)
         self._logger.debug('Sent server\'s opening handshake: %r',
                            raw_response)
 # vi:sts=4 sw=4 et

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testing/mochitest/pywebsocket/mod_pywebsocket/handshake/hybi00.py@b8a032363ba2 (annotated)

testing/mochitest/pywebsocket/mod_pywebsocket/handshake/hybi00.py