diff options
Diffstat (limited to 'netlib/http/http2/frame.py')
| -rw-r--r-- | netlib/http/http2/frame.py | 654 |
1 files changed, 654 insertions, 0 deletions
diff --git a/netlib/http/http2/frame.py b/netlib/http/http2/frame.py new file mode 100644 index 00000000..cb2cde99 --- /dev/null +++ b/netlib/http/http2/frame.py @@ -0,0 +1,654 @@ +from __future__ import absolute_import, print_function, division +import struct +from hpack.hpack import Encoder, Decoder + +from ...utils import BiDi +from ...exceptions import HttpSyntaxException + + +ERROR_CODES = 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" + +ALPN_PROTO_H2 = b'h2' + + +class Frame(object): + + """ + Baseclass Frame + contains header + payload is defined in subclasses + """ + + FLAG_NO_FLAGS = 0x0 + FLAG_ACK = 0x1 + FLAG_END_STREAM = 0x1 + FLAG_END_HEADERS = 0x4 + FLAG_PADDED = 0x8 + FLAG_PRIORITY = 0x20 + + def __init__( + self, + state=None, + length=0, + flags=FLAG_NO_FLAGS, + stream_id=0x0): + valid_flags = 0 + for flag in self.VALID_FLAGS: + valid_flags |= flag + if flags | valid_flags != valid_flags: + raise ValueError('invalid flags detected.') + + if state is None: + class State(object): + pass + + state = State() + state.http2_settings = HTTP2_DEFAULT_SETTINGS.copy() + state.encoder = Encoder() + state.decoder = Decoder() + + self.state = state + + self.length = length + self.type = self.TYPE + self.flags = flags + self.stream_id = stream_id + + @classmethod + def _check_frame_size(cls, length, state): + if state: + settings = state.http2_settings + else: + settings = HTTP2_DEFAULT_SETTINGS.copy() + + max_frame_size = settings[ + SettingsFrame.SETTINGS.SETTINGS_MAX_FRAME_SIZE] + + if length > max_frame_size: + raise HttpSyntaxException( + "Frame size exceeded: %d, but only %d allowed." % ( + length, max_frame_size)) + + @classmethod + def from_file(cls, fp, state=None): + """ + read a HTTP/2 frame sent by a server or client + fp is a "file like" object that could be backed by a network + stream or a disk or an in memory stream reader + """ + raw_header = fp.safe_read(9) + + fields = struct.unpack("!HBBBL", raw_header) + length = (fields[0] << 8) + fields[1] + flags = fields[3] + stream_id = fields[4] + + if raw_header[:4] == b'HTTP': # pragma no cover + raise HttpSyntaxException("Expected HTTP2 Frame, got HTTP/1 connection") + + cls._check_frame_size(length, state) + + payload = fp.safe_read(length) + return FRAMES[fields[2]].from_bytes( + state, + length, + flags, + stream_id, + payload) + + def to_bytes(self): + payload = self.payload_bytes() + self.length = len(payload) + + self._check_frame_size(self.length, self.state) + + b = struct.pack('!HB', (self.length & 0xFFFF00) >> 8, self.length & 0x0000FF) + b += struct.pack('!B', self.TYPE) + b += struct.pack('!B', self.flags) + b += struct.pack('!L', self.stream_id & 0x7FFFFFFF) + b += payload + + return b + + def payload_bytes(self): # pragma: no cover + raise NotImplementedError() + + def payload_human_readable(self): # pragma: no cover + raise NotImplementedError() + + def human_readable(self, direction="-"): + self.length = len(self.payload_bytes()) + + return "\n".join([ + "%s: %s | length: %d | flags: %#x | stream_id: %d" % ( + direction, self.__class__.__name__, self.length, self.flags, self.stream_id), + self.payload_human_readable(), + "===============================================================", + ]) + + def __eq__(self, other): + return self.to_bytes() == other.to_bytes() + + +class DataFrame(Frame): + TYPE = 0x0 + VALID_FLAGS = [Frame.FLAG_END_STREAM, Frame.FLAG_PADDED] + + def __init__( + self, + state=None, + length=0, + flags=Frame.FLAG_NO_FLAGS, + stream_id=0x0, + payload=b'', + pad_length=0): + super(DataFrame, self).__init__(state, length, flags, stream_id) + self.payload = payload + self.pad_length = pad_length + + @classmethod + def from_bytes(cls, state, length, flags, stream_id, payload): + f = cls(state=state, length=length, flags=flags, stream_id=stream_id) + + if f.flags & Frame.FLAG_PADDED: + f.pad_length = struct.unpack('!B', payload[0])[0] + f.payload = payload[1:-f.pad_length] + else: + f.payload = payload + + return f + + def payload_bytes(self): + if self.stream_id == 0x0: + raise ValueError('DATA frames MUST be associated with a stream.') + + b = b'' + if self.flags & self.FLAG_PADDED: + b += struct.pack('!B', self.pad_length) + + b += bytes(self.payload) + + if self.flags & self.FLAG_PADDED: + b += b'\0' * self.pad_length + + return b + + def payload_human_readable(self): + return "payload: %s" % str(self.payload) + + +class HeadersFrame(Frame): + TYPE = 0x1 + VALID_FLAGS = [ + Frame.FLAG_END_STREAM, + Frame.FLAG_END_HEADERS, + Frame.FLAG_PADDED, + Frame.FLAG_PRIORITY] + + def __init__( + self, + state=None, + length=0, + flags=Frame.FLAG_NO_FLAGS, + stream_id=0x0, + header_block_fragment=b'', + pad_length=0, + exclusive=False, + stream_dependency=0x0, + weight=0): + super(HeadersFrame, self).__init__(state, length, flags, stream_id) + + self.header_block_fragment = header_block_fragment + self.pad_length = pad_length + self.exclusive = exclusive + self.stream_dependency = stream_dependency + self.weight = weight + + @classmethod + def from_bytes(cls, state, length, flags, stream_id, payload): + f = cls(state=state, length=length, flags=flags, stream_id=stream_id) + + if f.flags & Frame.FLAG_PADDED: + f.pad_length = struct.unpack('!B', payload[0])[0] + f.header_block_fragment = payload[1:-f.pad_length] + else: + f.header_block_fragment = payload[0:] + + if f.flags & Frame.FLAG_PRIORITY: + f.stream_dependency, f.weight = struct.unpack( + '!LB', f.header_block_fragment[:5]) + f.exclusive = bool(f.stream_dependency >> 31) + f.stream_dependency &= 0x7FFFFFFF + f.header_block_fragment = f.header_block_fragment[5:] + + return f + + def payload_bytes(self): + if self.stream_id == 0x0: + raise ValueError('HEADERS frames MUST be associated with a stream.') + + b = b'' + if self.flags & self.FLAG_PADDED: + b += struct.pack('!B', self.pad_length) + + if self.flags & self.FLAG_PRIORITY: + b += struct.pack('!LB', + (int(self.exclusive) << 31) | self.stream_dependency, + self.weight) + + b += self.header_block_fragment + + if self.flags & self.FLAG_PADDED: + b += b'\0' * self.pad_length + + return b + + def payload_human_readable(self): + s = [] + + if self.flags & self.FLAG_PRIORITY: + s.append("exclusive: %d" % self.exclusive) + s.append("stream dependency: %#x" % self.stream_dependency) + s.append("weight: %d" % self.weight) + + if self.flags & self.FLAG_PADDED: + s.append("padding: %d" % self.pad_length) + + s.append( + "header_block_fragment: %s" % + self.header_block_fragment.encode('hex')) + + return "\n".join(s) + + +class PriorityFrame(Frame): + TYPE = 0x2 + VALID_FLAGS = [] + + def __init__( + self, + state=None, + length=0, + flags=Frame.FLAG_NO_FLAGS, + stream_id=0x0, + exclusive=False, + stream_dependency=0x0, + weight=0): + super(PriorityFrame, self).__init__(state, length, flags, stream_id) + self.exclusive = exclusive + self.stream_dependency = stream_dependency + self.weight = weight + + @classmethod + def from_bytes(cls, state, length, flags, stream_id, payload): + f = cls(state=state, length=length, flags=flags, stream_id=stream_id) + + f.stream_dependency, f.weight = struct.unpack('!LB', payload) + f.exclusive = bool(f.stream_dependency >> 31) + f.stream_dependency &= 0x7FFFFFFF + + return f + + def payload_bytes(self): + if self.stream_id == 0x0: + raise ValueError( + 'PRIORITY frames MUST be associated with a stream.') + + return struct.pack( + '!LB', + (int( + self.exclusive) << 31) | self.stream_dependency, + self.weight) + + def payload_human_readable(self): + s = [] + s.append("exclusive: %d" % self.exclusive) + s.append("stream dependency: %#x" % self.stream_dependency) + s.append("weight: %d" % self.weight) + return "\n".join(s) + + +class RstStreamFrame(Frame): + TYPE = 0x3 + VALID_FLAGS = [] + + def __init__( + self, + state=None, + length=0, + flags=Frame.FLAG_NO_FLAGS, + stream_id=0x0, + error_code=0x0): + super(RstStreamFrame, self).__init__(state, length, flags, stream_id) + self.error_code = error_code + + @classmethod + def from_bytes(cls, state, length, flags, stream_id, payload): + f = cls(state=state, length=length, flags=flags, stream_id=stream_id) + f.error_code = struct.unpack('!L', payload)[0] + return f + + def payload_bytes(self): + if self.stream_id == 0x0: + raise ValueError( + 'RST_STREAM frames MUST be associated with a stream.') + + return struct.pack('!L', self.error_code) + + def payload_human_readable(self): + return "error code: %#x" % self.error_code + + +class SettingsFrame(Frame): + TYPE = 0x4 + VALID_FLAGS = [Frame.FLAG_ACK] + + SETTINGS = BiDi( + SETTINGS_HEADER_TABLE_SIZE=0x1, + SETTINGS_ENABLE_PUSH=0x2, + SETTINGS_MAX_CONCURRENT_STREAMS=0x3, + SETTINGS_INITIAL_WINDOW_SIZE=0x4, + SETTINGS_MAX_FRAME_SIZE=0x5, + SETTINGS_MAX_HEADER_LIST_SIZE=0x6, + ) + + def __init__( + self, + state=None, + length=0, + flags=Frame.FLAG_NO_FLAGS, + stream_id=0x0, + settings=None): + super(SettingsFrame, self).__init__(state, length, flags, stream_id) + + if settings is None: + settings = {} + + self.settings = settings + + @classmethod + def from_bytes(cls, state, length, flags, stream_id, payload): + f = cls(state=state, length=length, flags=flags, stream_id=stream_id) + + for i in range(0, len(payload), 6): + identifier, value = struct.unpack("!HL", payload[i:i + 6]) + f.settings[identifier] = value + + return f + + def payload_bytes(self): + if self.stream_id != 0x0: + raise ValueError( + 'SETTINGS frames MUST NOT be associated with a stream.') + + b = b'' + for identifier, value in self.settings.items(): + b += struct.pack("!HL", identifier & 0xFF, value) + + return b + + def payload_human_readable(self): + s = [] + + for identifier, value in self.settings.items(): + s.append("%s: %#x" % (self.SETTINGS.get_name(identifier), value)) + + if not s: + return "settings: None" + else: + return "\n".join(s) + + +class PushPromiseFrame(Frame): + TYPE = 0x5 + VALID_FLAGS = [Frame.FLAG_END_HEADERS, Frame.FLAG_PADDED] + + def __init__( + self, + state=None, + length=0, + flags=Frame.FLAG_NO_FLAGS, + stream_id=0x0, + promised_stream=0x0, + header_block_fragment=b'', + pad_length=0): + super(PushPromiseFrame, self).__init__(state, length, flags, stream_id) + self.pad_length = pad_length + self.promised_stream = promised_stream + self.header_block_fragment = header_block_fragment + + @classmethod + def from_bytes(cls, state, length, flags, stream_id, payload): + f = cls(state=state, length=length, flags=flags, stream_id=stream_id) + + if f.flags & Frame.FLAG_PADDED: + f.pad_length, f.promised_stream = struct.unpack('!BL', payload[:5]) + f.header_block_fragment = payload[5:-f.pad_length] + else: + f.promised_stream = int(struct.unpack("!L", payload[:4])[0]) + f.header_block_fragment = payload[4:] + + f.promised_stream &= 0x7FFFFFFF + + return f + + def payload_bytes(self): + if self.stream_id == 0x0: + raise ValueError( + 'PUSH_PROMISE frames MUST be associated with a stream.') + + if self.promised_stream == 0x0: + raise ValueError('Promised stream id not valid.') + + b = b'' + if self.flags & self.FLAG_PADDED: + b += struct.pack('!B', self.pad_length) + + b += struct.pack('!L', self.promised_stream & 0x7FFFFFFF) + b += bytes(self.header_block_fragment) + + if self.flags & self.FLAG_PADDED: + b += b'\0' * self.pad_length + + return b + + def payload_human_readable(self): + s = [] + + if self.flags & self.FLAG_PADDED: + s.append("padding: %d" % self.pad_length) + + s.append("promised stream: %#x" % self.promised_stream) + s.append( + "header_block_fragment: %s" % + self.header_block_fragment.encode('hex')) + + return "\n".join(s) + + +class PingFrame(Frame): + TYPE = 0x6 + VALID_FLAGS = [Frame.FLAG_ACK] + + def __init__( + self, + state=None, + length=0, + flags=Frame.FLAG_NO_FLAGS, + stream_id=0x0, + payload=b''): + super(PingFrame, self).__init__(state, length, flags, stream_id) + self.payload = payload + + @classmethod + def from_bytes(cls, state, length, flags, stream_id, payload): + f = cls(state=state, length=length, flags=flags, stream_id=stream_id) + f.payload = payload + return f + + def payload_bytes(self): + if self.stream_id != 0x0: + raise ValueError( + 'PING frames MUST NOT be associated with a stream.') + + b = self.payload[0:8] + b += b'\0' * (8 - len(b)) + return b + + def payload_human_readable(self): + return "opaque data: %s" % str(self.payload) + + +class GoAwayFrame(Frame): + TYPE = 0x7 + VALID_FLAGS = [] + + def __init__( + self, + state=None, + length=0, + flags=Frame.FLAG_NO_FLAGS, + stream_id=0x0, + last_stream=0x0, + error_code=0x0, + data=b''): + super(GoAwayFrame, self).__init__(state, length, flags, stream_id) + self.last_stream = last_stream + self.error_code = error_code + self.data = data + + @classmethod + def from_bytes(cls, state, length, flags, stream_id, payload): + f = cls(state=state, length=length, flags=flags, stream_id=stream_id) + + f.last_stream, f.error_code = struct.unpack("!LL", payload[:8]) + f.last_stream &= 0x7FFFFFFF + f.data = payload[8:] + + return f + + def payload_bytes(self): + if self.stream_id != 0x0: + raise ValueError( + 'GOAWAY frames MUST NOT be associated with a stream.') + + b = struct.pack('!LL', self.last_stream & 0x7FFFFFFF, self.error_code) + b += bytes(self.data) + return b + + def payload_human_readable(self): + s = [] + s.append("last stream: %#x" % self.last_stream) + s.append("error code: %d" % self.error_code) + s.append("debug data: %s" % str(self.data)) + return "\n".join(s) + + +class WindowUpdateFrame(Frame): + TYPE = 0x8 + VALID_FLAGS = [] + + def __init__( + self, + state=None, + length=0, + flags=Frame.FLAG_NO_FLAGS, + stream_id=0x0, + window_size_increment=0x0): + super(WindowUpdateFrame, self).__init__(state, length, flags, stream_id) + self.window_size_increment = window_size_increment + + @classmethod + def from_bytes(cls, state, length, flags, stream_id, payload): + f = cls(state=state, length=length, flags=flags, stream_id=stream_id) + + f.window_size_increment = struct.unpack("!L", payload)[0] + f.window_size_increment &= 0x7FFFFFFF + + return f + + def payload_bytes(self): + if self.window_size_increment <= 0 or self.window_size_increment >= 2 ** 31: + raise ValueError( + 'Window Size Increment MUST be greater than 0 and less than 2^31.') + + return struct.pack('!L', self.window_size_increment & 0x7FFFFFFF) + + def payload_human_readable(self): + return "window size increment: %#x" % self.window_size_increment + + +class ContinuationFrame(Frame): + TYPE = 0x9 + VALID_FLAGS = [Frame.FLAG_END_HEADERS] + + def __init__( + self, + state=None, + length=0, + flags=Frame.FLAG_NO_FLAGS, + stream_id=0x0, + header_block_fragment=b''): + super(ContinuationFrame, self).__init__(state, length, flags, stream_id) + self.header_block_fragment = header_block_fragment + + @classmethod + def from_bytes(cls, state, length, flags, stream_id, payload): + f = cls(state=state, length=length, flags=flags, stream_id=stream_id) + f.header_block_fragment = payload + return f + + def payload_bytes(self): + if self.stream_id == 0x0: + raise ValueError( + 'CONTINUATION frames MUST be associated with a stream.') + + return self.header_block_fragment + + def payload_human_readable(self): + s = [] + s.append( + "header_block_fragment: %s" % + self.header_block_fragment.encode('hex')) + return "\n".join(s) + +_FRAME_CLASSES = [ + DataFrame, + HeadersFrame, + PriorityFrame, + RstStreamFrame, + SettingsFrame, + PushPromiseFrame, + PingFrame, + GoAwayFrame, + WindowUpdateFrame, + ContinuationFrame +] +FRAMES = {cls.TYPE: cls for cls in _FRAME_CLASSES} + + +HTTP2_DEFAULT_SETTINGS = { + SettingsFrame.SETTINGS.SETTINGS_HEADER_TABLE_SIZE: 4096, + SettingsFrame.SETTINGS.SETTINGS_ENABLE_PUSH: 1, + SettingsFrame.SETTINGS.SETTINGS_MAX_CONCURRENT_STREAMS: None, + SettingsFrame.SETTINGS.SETTINGS_INITIAL_WINDOW_SIZE: 2 ** 16 - 1, + SettingsFrame.SETTINGS.SETTINGS_MAX_FRAME_SIZE: 2 ** 14, + SettingsFrame.SETTINGS.SETTINGS_MAX_HEADER_LIST_SIZE: None, +} |