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Diffstat (limited to 'testing/mochitest/pywebsocket/mod_pywebsocket/handshake/hybi.py')
| -rw-r--r-- | testing/mochitest/pywebsocket/mod_pywebsocket/handshake/hybi.py | 428 |
1 files changed, 428 insertions, 0 deletions
diff --git a/testing/mochitest/pywebsocket/mod_pywebsocket/handshake/hybi.py b/testing/mochitest/pywebsocket/mod_pywebsocket/handshake/hybi.py new file mode 100644 index 000000000..44e71f179 --- /dev/null +++ b/testing/mochitest/pywebsocket/mod_pywebsocket/handshake/hybi.py @@ -0,0 +1,428 @@ +# Copyright 2012, 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 (RFC 6455). + +Specification: +http://tools.ietf.org/html/rfc6455 +""" + + +# Note: request.connection.write is used in this module, even though mod_python +# document says that it should be used only in connection handlers. +# Unfortunately, we have no other options. For example, request.write is not +# suitable because it doesn't allow direct raw bytes writing. + + +import base64 +import logging +import os +import re + +from mod_pywebsocket import common +from mod_pywebsocket.extensions import get_extension_processor +from mod_pywebsocket.extensions import is_compression_extension +from mod_pywebsocket.handshake._base import check_request_line +from mod_pywebsocket.handshake._base import format_header +from mod_pywebsocket.handshake._base import get_mandatory_header +from mod_pywebsocket.handshake._base import HandshakeException +from mod_pywebsocket.handshake._base import parse_token_list +from mod_pywebsocket.handshake._base import validate_mandatory_header +from mod_pywebsocket.handshake._base import validate_subprotocol +from mod_pywebsocket.handshake._base import VersionException +from mod_pywebsocket.stream import Stream +from mod_pywebsocket.stream import StreamOptions +from mod_pywebsocket import util + + +# Used to validate the value in the Sec-WebSocket-Key header strictly. RFC 4648 +# disallows non-zero padding, so the character right before == must be any of +# A, Q, g and w. +_SEC_WEBSOCKET_KEY_REGEX = re.compile('^[+/0-9A-Za-z]{21}[AQgw]==$') + +# Defining aliases for values used frequently. +_VERSION_LATEST = common.VERSION_HYBI_LATEST +_VERSION_LATEST_STRING = str(_VERSION_LATEST) +_SUPPORTED_VERSIONS = [ + _VERSION_LATEST, +] + + +def compute_accept(key): + """Computes value for the Sec-WebSocket-Accept header from value of the + Sec-WebSocket-Key header. + """ + + accept_binary = util.sha1_hash( + key + common.WEBSOCKET_ACCEPT_UUID).digest() + accept = base64.b64encode(accept_binary) + + return (accept, accept_binary) + + +class Handshaker(object): + """Opening handshake processor for the WebSocket protocol (RFC 6455).""" + + 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 during handshake. + """ + + self._logger = util.get_class_logger(self) + + self._request = request + self._dispatcher = dispatcher + + def _validate_connection_header(self): + connection = get_mandatory_header( + self._request, common.CONNECTION_HEADER) + + try: + connection_tokens = parse_token_list(connection) + except HandshakeException, e: + raise HandshakeException( + 'Failed to parse %s: %s' % (common.CONNECTION_HEADER, e)) + + connection_is_valid = False + for token in connection_tokens: + if token.lower() == common.UPGRADE_CONNECTION_TYPE.lower(): + connection_is_valid = True + break + if not connection_is_valid: + raise HandshakeException( + '%s header doesn\'t contain "%s"' % + (common.CONNECTION_HEADER, common.UPGRADE_CONNECTION_TYPE)) + + def do_handshake(self): + self._request.ws_close_code = None + self._request.ws_close_reason = None + + # Parsing. + + check_request_line(self._request) + + validate_mandatory_header( + self._request, + common.UPGRADE_HEADER, + common.WEBSOCKET_UPGRADE_TYPE) + + self._validate_connection_header() + + self._request.ws_resource = self._request.uri + + unused_host = get_mandatory_header(self._request, common.HOST_HEADER) + + self._request.ws_version = self._check_version() + + try: + self._get_origin() + self._set_protocol() + self._parse_extensions() + + # Key validation, response generation. + + key = self._get_key() + (accept, accept_binary) = compute_accept(key) + self._logger.debug( + '%s: %r (%s)', + common.SEC_WEBSOCKET_ACCEPT_HEADER, + accept, + util.hexify(accept_binary)) + + self._logger.debug('Protocol version is RFC 6455') + + # Setup extension processors. + + processors = [] + if self._request.ws_requested_extensions is not None: + for extension_request in self._request.ws_requested_extensions: + processor = get_extension_processor(extension_request) + # Unknown extension requests are just ignored. + if processor is not None: + processors.append(processor) + self._request.ws_extension_processors = processors + + # List of extra headers. The extra handshake handler may add header + # data as name/value pairs to this list and pywebsocket appends + # them to the WebSocket handshake. + self._request.extra_headers = [] + + # Extra handshake handler may modify/remove processors. + self._dispatcher.do_extra_handshake(self._request) + processors = filter(lambda processor: processor is not None, + self._request.ws_extension_processors) + + # Ask each processor if there are extensions on the request which + # cannot co-exist. When processor decided other processors cannot + # co-exist with it, the processor marks them (or itself) as + # "inactive". The first extension processor has the right to + # make the final call. + for processor in reversed(processors): + if processor.is_active(): + processor.check_consistency_with_other_processors( + processors) + processors = filter(lambda processor: processor.is_active(), + processors) + + accepted_extensions = [] + + # We need to take into account of mux extension here. + # If mux extension exists: + # - Remove processors of extensions for logical channel, + # which are processors located before the mux processor + # - Pass extension requests for logical channel to mux processor + # - Attach the mux processor to the request. It will be referred + # by dispatcher to see whether the dispatcher should use mux + # handler or not. + mux_index = -1 + for i, processor in enumerate(processors): + if processor.name() == common.MUX_EXTENSION: + mux_index = i + break + if mux_index >= 0: + logical_channel_extensions = [] + for processor in processors[:mux_index]: + logical_channel_extensions.append(processor.request()) + processor.set_active(False) + self._request.mux_processor = processors[mux_index] + self._request.mux_processor.set_extensions( + logical_channel_extensions) + processors = filter(lambda processor: processor.is_active(), + processors) + + stream_options = StreamOptions() + + for index, processor in enumerate(processors): + if not processor.is_active(): + continue + + extension_response = processor.get_extension_response() + if extension_response is None: + # Rejected. + continue + + accepted_extensions.append(extension_response) + + processor.setup_stream_options(stream_options) + + if not is_compression_extension(processor.name()): + continue + + # Inactivate all of the following compression extensions. + for j in xrange(index + 1, len(processors)): + if is_compression_extension(processors[j].name()): + processors[j].set_active(False) + + if len(accepted_extensions) > 0: + self._request.ws_extensions = accepted_extensions + self._logger.debug( + 'Extensions accepted: %r', + map(common.ExtensionParameter.name, accepted_extensions)) + else: + self._request.ws_extensions = None + + self._request.ws_stream = self._create_stream(stream_options) + + if self._request.ws_requested_protocols is not None: + if self._request.ws_protocol is None: + raise HandshakeException( + 'do_extra_handshake must choose one subprotocol from ' + 'ws_requested_protocols and set it to ws_protocol') + validate_subprotocol(self._request.ws_protocol) + + self._logger.debug( + 'Subprotocol accepted: %r', + self._request.ws_protocol) + else: + if self._request.ws_protocol is not None: + raise HandshakeException( + 'ws_protocol must be None when the client didn\'t ' + 'request any subprotocol') + + self._send_handshake(accept) + except HandshakeException, e: + if not e.status: + # Fallback to 400 bad request by default. + e.status = common.HTTP_STATUS_BAD_REQUEST + raise e + + def _get_origin(self): + origin_header = common.ORIGIN_HEADER + origin = self._request.headers_in.get(origin_header) + if origin is None: + self._logger.debug('Client request does not have origin header') + self._request.ws_origin = origin + + def _check_version(self): + version = get_mandatory_header(self._request, + common.SEC_WEBSOCKET_VERSION_HEADER) + if version == _VERSION_LATEST_STRING: + return _VERSION_LATEST + + if version.find(',') >= 0: + raise HandshakeException( + 'Multiple versions (%r) are not allowed for header %s' % + (version, common.SEC_WEBSOCKET_VERSION_HEADER), + status=common.HTTP_STATUS_BAD_REQUEST) + raise VersionException( + 'Unsupported version %r for header %s' % + (version, common.SEC_WEBSOCKET_VERSION_HEADER), + supported_versions=', '.join(map(str, _SUPPORTED_VERSIONS))) + + def _set_protocol(self): + self._request.ws_protocol = None + # MOZILLA + self._request.sts = None + # /MOZILLA + + protocol_header = self._request.headers_in.get( + common.SEC_WEBSOCKET_PROTOCOL_HEADER) + + if protocol_header is None: + self._request.ws_requested_protocols = None + return + + self._request.ws_requested_protocols = parse_token_list( + protocol_header) + self._logger.debug('Subprotocols requested: %r', + self._request.ws_requested_protocols) + + def _parse_extensions(self): + extensions_header = self._request.headers_in.get( + common.SEC_WEBSOCKET_EXTENSIONS_HEADER) + if not extensions_header: + self._request.ws_requested_extensions = None + return + + try: + self._request.ws_requested_extensions = common.parse_extensions( + extensions_header) + except common.ExtensionParsingException, e: + raise HandshakeException( + 'Failed to parse Sec-WebSocket-Extensions header: %r' % e) + + self._logger.debug( + 'Extensions requested: %r', + map(common.ExtensionParameter.name, + self._request.ws_requested_extensions)) + + def _validate_key(self, key): + if key.find(',') >= 0: + raise HandshakeException('Request has multiple %s header lines or ' + 'contains illegal character \',\': %r' % + (common.SEC_WEBSOCKET_KEY_HEADER, key)) + + # Validate + key_is_valid = False + try: + # Validate key by quick regex match before parsing by base64 + # module. Because base64 module skips invalid characters, we have + # to do this in advance to make this server strictly reject illegal + # keys. + if _SEC_WEBSOCKET_KEY_REGEX.match(key): + decoded_key = base64.b64decode(key) + if len(decoded_key) == 16: + key_is_valid = True + except TypeError, e: + pass + + if not key_is_valid: + raise HandshakeException( + 'Illegal value for header %s: %r' % + (common.SEC_WEBSOCKET_KEY_HEADER, key)) + + return decoded_key + + def _get_key(self): + key = get_mandatory_header( + self._request, common.SEC_WEBSOCKET_KEY_HEADER) + + decoded_key = self._validate_key(key) + + self._logger.debug( + '%s: %r (%s)', + common.SEC_WEBSOCKET_KEY_HEADER, + key, + util.hexify(decoded_key)) + + return key + + def _create_stream(self, stream_options): + return Stream(self._request, stream_options) + + def _create_handshake_response(self, accept): + response = [] + + response.append('HTTP/1.1 101 Switching Protocols\r\n') + + # WebSocket headers + response.append(format_header( + common.UPGRADE_HEADER, common.WEBSOCKET_UPGRADE_TYPE)) + response.append(format_header( + common.CONNECTION_HEADER, common.UPGRADE_CONNECTION_TYPE)) + response.append(format_header( + common.SEC_WEBSOCKET_ACCEPT_HEADER, accept)) + if self._request.ws_protocol is not None: + response.append(format_header( + common.SEC_WEBSOCKET_PROTOCOL_HEADER, + self._request.ws_protocol)) + if (self._request.ws_extensions is not None and + len(self._request.ws_extensions) != 0): + response.append(format_header( + common.SEC_WEBSOCKET_EXTENSIONS_HEADER, + common.format_extensions(self._request.ws_extensions))) + # MOZILLA: Add HSTS header if requested to + if self._request.sts is not None: + response.append(format_header("Strict-Transport-Security", + self._request.sts)) + # /MOZILLA + + # Headers not specific for WebSocket + for name, value in self._request.extra_headers: + response.append(format_header(name, value)) + + response.append('\r\n') + + return ''.join(response) + + def _send_handshake(self, accept): + raw_response = self._create_handshake_response(accept) + self._request.connection.write(raw_response) + self._logger.debug('Sent server\'s opening handshake: %r', + raw_response) + + +# vi:sts=4 sw=4 et |