import itertools import time import hyperframe.frame from hpack.hpack import Encoder, Decoder from netlib import utils from netlib.http import http2 import netlib.http.headers import netlib.http.response import netlib.http.request from .. import language class TCPHandler: def __init__(self, rfile, wfile=None): self.rfile = rfile self.wfile = wfile class HTTP2StateProtocol: ERROR_CODES = utils.BiDi( NO_ERROR=0x0, PROTOCOL_ERROR=0x1, INTERNAL_ERROR=0x2, FLOW_CONTROL_ERROR=0x3, SETTINGS_TIMEOUT=0x4, STREAM_CLOSED=0x5, FRAME_SIZE_ERROR=0x6, REFUSED_STREAM=0x7, CANCEL=0x8, COMPRESSION_ERROR=0x9, CONNECT_ERROR=0xa, ENHANCE_YOUR_CALM=0xb, INADEQUATE_SECURITY=0xc, HTTP_1_1_REQUIRED=0xd ) CLIENT_CONNECTION_PREFACE = b'PRI * HTTP/2.0\r\n\r\nSM\r\n\r\n' HTTP2_DEFAULT_SETTINGS = { hyperframe.frame.SettingsFrame.HEADER_TABLE_SIZE: 4096, hyperframe.frame.SettingsFrame.ENABLE_PUSH: 1, hyperframe.frame.SettingsFrame.MAX_CONCURRENT_STREAMS: None, hyperframe.frame.SettingsFrame.INITIAL_WINDOW_SIZE: 2 ** 16 - 1, hyperframe.frame.SettingsFrame.MAX_FRAME_SIZE: 2 ** 14, hyperframe.frame.SettingsFrame.MAX_HEADER_LIST_SIZE: None, } def __init__( self, tcp_handler=None, rfile=None, wfile=None, is_server=False, dump_frames=False, encoder=None, decoder=None, unhandled_frame_cb=None, ): self.tcp_handler = tcp_handler or TCPHandler(rfile, wfile) self.is_server = is_server self.dump_frames = dump_frames self.encoder = encoder or Encoder() self.decoder = decoder or Decoder() self.unhandled_frame_cb = unhandled_frame_cb self.http2_settings = self.HTTP2_DEFAULT_SETTINGS.copy() self.current_stream_id = None self.connection_preface_performed = False def read_request( self, __rfile, include_body=True, body_size_limit=None, allow_empty=False, ): if body_size_limit is not None: raise NotImplementedError() self.perform_connection_preface() timestamp_start = time.time() if hasattr(self.tcp_handler.rfile, "reset_timestamps"): self.tcp_handler.rfile.reset_timestamps() stream_id, headers, body = self._receive_transmission( include_body=include_body, ) if hasattr(self.tcp_handler.rfile, "first_byte_timestamp"): # more accurate timestamp_start timestamp_start = self.tcp_handler.rfile.first_byte_timestamp timestamp_end = time.time() first_line_format, method, scheme, host, port, path = http2.parse_headers(headers) request = netlib.http.request.Request( first_line_format, method, scheme, host, port, path, b"HTTP/2.0", headers, body, timestamp_start, timestamp_end, ) request.stream_id = stream_id return request def read_response( self, __rfile, request_method=b'', body_size_limit=None, include_body=True, stream_id=None, ): if body_size_limit is not None: raise NotImplementedError() self.perform_connection_preface() timestamp_start = time.time() if hasattr(self.tcp_handler.rfile, "reset_timestamps"): self.tcp_handler.rfile.reset_timestamps() stream_id, headers, body = self._receive_transmission( stream_id=stream_id, include_body=include_body, ) if hasattr(self.tcp_handler.rfile, "first_byte_timestamp"): # more accurate timestamp_start timestamp_start = self.tcp_handler.rfile.first_byte_timestamp if include_body: timestamp_end = time.time() else: timestamp_end = None response = netlib.http.response.Response( b"HTTP/2.0", int(headers.get(':status', 502)), b'', headers, body, timestamp_start=timestamp_start, timestamp_end=timestamp_end, ) response.stream_id = stream_id return response def assemble(self, message): if isinstance(message, netlib.http.request.Request): return self.assemble_request(message) elif isinstance(message, netlib.http.response.Response): return self.assemble_response(message) else: raise ValueError("HTTP message not supported.") def assemble_request(self, request): assert isinstance(request, netlib.http.request.Request) authority = self.tcp_handler.sni if self.tcp_handler.sni else self.tcp_handler.address.host if self.tcp_handler.address.port != 443: authority += ":%d" % self.tcp_handler.address.port headers = request.headers.copy() if ':authority' not in headers: headers.insert(0, ':authority', authority) headers.insert(0, ':scheme', request.scheme) headers.insert(0, ':path', request.path) headers.insert(0, ':method', request.method) if hasattr(request, 'stream_id'): stream_id = request.stream_id else: stream_id = self._next_stream_id() return list(itertools.chain( self._create_headers(headers, stream_id, end_stream=(request.body is None or len(request.body) == 0)), self._create_body(request.body, stream_id))) def assemble_response(self, response): assert isinstance(response, netlib.http.response.Response) headers = response.headers.copy() if ':status' not in headers: headers.insert(0, b':status', str(response.status_code).encode()) if hasattr(response, 'stream_id'): stream_id = response.stream_id else: stream_id = self._next_stream_id() return list(itertools.chain( self._create_headers(headers, stream_id, end_stream=(response.body is None or len(response.body) == 0)), self._create_body(response.body, stream_id), )) def perform_connection_preface(self, force=False): if force or not self.connection_preface_performed: if self.is_server: self.perform_server_connection_preface(force) else: self.perform_client_connection_preface(force) def perform_server_connection_preface(self, force=False): if force or not self.connection_preface_performed: self.connection_preface_performed = True magic_length = len(self.CLIENT_CONNECTION_PREFACE) magic = self.tcp_handler.rfile.safe_read(magic_length) assert magic == self.CLIENT_CONNECTION_PREFACE frm = hyperframe.frame.SettingsFrame(settings={ hyperframe.frame.SettingsFrame.ENABLE_PUSH: 0, hyperframe.frame.SettingsFrame.MAX_CONCURRENT_STREAMS: 1, }) self.send_frame(frm, hide=True) self._receive_settings(hide=True) def perform_client_connection_preface(self, force=False): if force or not self.connection_preface_performed: self.connection_preface_performed = True self.tcp_handler.wfile.write(self.CLIENT_CONNECTION_PREFACE) self.send_frame(hyperframe.frame.SettingsFrame(), hide=True) self._receive_settings(hide=True) # server announces own settings self._receive_settings(hide=True) # server acks my settings def send_frame(self, frm, hide=False): raw_bytes = frm.serialize() self.tcp_handler.wfile.write(raw_bytes) self.tcp_handler.wfile.flush() if not hide and self.dump_frames: # pragma no cover print(">> " + repr(frm)) def read_frame(self, hide=False): while True: frm = http2.parse_frame(*http2.read_raw_frame(self.tcp_handler.rfile)) if not hide and self.dump_frames: # pragma no cover print("<< " + repr(frm)) if isinstance(frm, hyperframe.frame.PingFrame): raw_bytes = hyperframe.frame.PingFrame(flags=['ACK'], payload=frm.payload).serialize() self.tcp_handler.wfile.write(raw_bytes) self.tcp_handler.wfile.flush() continue if isinstance(frm, hyperframe.frame.SettingsFrame) and 'ACK' not in frm.flags: self._apply_settings(frm.settings, hide) if isinstance(frm, hyperframe.frame.DataFrame) and frm.flow_controlled_length > 0: self._update_flow_control_window(frm.stream_id, frm.flow_controlled_length) return frm def check_alpn(self): alp = self.tcp_handler.get_alpn_proto_negotiated() if alp != b'h2': raise NotImplementedError( "HTTP2Protocol can not handle unknown ALPN value: %s" % alp) return True def _handle_unexpected_frame(self, frm): if isinstance(frm, hyperframe.frame.SettingsFrame): return if self.unhandled_frame_cb: self.unhandled_frame_cb(frm) def _receive_settings(self, hide=False): while True: frm = self.read_frame(hide) if isinstance(frm, hyperframe.frame.SettingsFrame): break else: self._handle_unexpected_frame(frm) def _next_stream_id(self): if self.current_stream_id is None: if self.is_server: # servers must use even stream ids self.current_stream_id = 2 else: # clients must use odd stream ids self.current_stream_id = 1 else: self.current_stream_id += 2 return self.current_stream_id def _apply_settings(self, settings, hide=False): for setting, value in settings.items(): old_value = self.http2_settings[setting] if not old_value: old_value = '-' self.http2_settings[setting] = value frm = hyperframe.frame.SettingsFrame(flags=['ACK']) self.send_frame(frm, hide) def _update_flow_control_window(self, stream_id, increment): frm = hyperframe.frame.WindowUpdateFrame(stream_id=0, window_increment=increment) self.send_frame(frm) frm = hyperframe.frame.WindowUpdateFrame(stream_id=stream_id, window_increment=increment) self.send_frame(frm) def _create_headers(self, headers, stream_id, end_stream=True): def frame_cls(chunks): for i in chunks: if i == 0: yield hyperframe.frame.HeadersFrame, i else: yield hyperframe.frame.ContinuationFrame, i header_block_fragment = self.encoder.encode(headers.fields) chunk_size = self.http2_settings[hyperframe.frame.SettingsFrame.MAX_FRAME_SIZE] chunks = range(0, len(header_block_fragment), chunk_size) frms = [frm_cls( flags=[], stream_id=stream_id, data=header_block_fragment[i:i + chunk_size]) for frm_cls, i in frame_cls(chunks)] frms[-1].flags.add('END_HEADERS') if end_stream: frms[0].flags.add('END_STREAM') if self.dump_frames: # pragma no cover for frm in frms: print(">> ", repr(frm)) return [frm.serialize() for frm in frms] def _create_body(self, body, stream_id): if body is None or len(body) == 0: return b'' chunk_size = self.http2_settings[hyperframe.frame.SettingsFrame.MAX_FRAME_SIZE] chunks = range(0, len(body), chunk_size) frms = [hyperframe.frame.DataFrame( flags=[], stream_id=stream_id, data=body[i:i + chunk_size]) for i in chunks] frms[-1].flags.add('END_STREAM') if self.dump_frames: # pragma no cover for frm in frms: print(">> ", repr(frm)) return [frm.serialize() for frm in frms] def _receive_transmission(self, stream_id=None, include_body=True): if not include_body: raise NotImplementedError() body_expected = True header_blocks = b'' body = b'' while True: frm = self.read_frame() if ( (isinstance(frm, hyperframe.frame.HeadersFrame) or isinstance(frm, hyperframe.frame.ContinuationFrame)) and (stream_id is None or frm.stream_id == stream_id) ): stream_id = frm.stream_id header_blocks += frm.data if 'END_STREAM' in frm.flags: body_expected = False if 'END_HEADERS' in frm.flags: break else: self._handle_unexpected_frame(frm) while body_expected: frm = self.read_frame() if isinstance(frm, hyperframe.frame.DataFrame) and frm.stream_id == stream_id: body += frm.data if 'END_STREAM' in frm.flags: break else: self._handle_unexpected_frame(frm) headers = netlib.http.headers.Headers( [[k, v] for k, v in self.decoder.decode(header_blocks, raw=True)] ) return stream_id, headers, body class HTTP2Protocol: def __init__(self, pathod_handler): self.pathod_handler = pathod_handler self.wire_protocol = HTTP2StateProtocol( self.pathod_handler, is_server=True, dump_frames=self.pathod_handler.http2_framedump ) def make_error_response(self, reason, body): return language.http2.make_error_response(reason, body) def read_request(self, lg=None): self.wire_protocol.perform_server_connection_preface() return self.wire_protocol.read_request(self.pathod_handler.rfile) def assemble(self, message): return self.wire_protocol.assemble(message)