aboutsummaryrefslogtreecommitdiffstats
path: root/netlib/http/http2/frame.py
diff options
context:
space:
mode:
Diffstat (limited to 'netlib/http/http2/frame.py')
-rw-r--r--netlib/http/http2/frame.py636
1 files changed, 636 insertions, 0 deletions
diff --git a/netlib/http/http2/frame.py b/netlib/http/http2/frame.py
new file mode 100644
index 00000000..f7e60471
--- /dev/null
+++ b/netlib/http/http2/frame.py
@@ -0,0 +1,636 @@
+import sys
+import struct
+from hpack.hpack import Encoder, Decoder
+
+from .. import utils
+
+
+class FrameSizeError(Exception):
+ pass
+
+
+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 = reduce(lambda x, y: x | y, self.VALID_FLAGS, 0x0)
+ 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 FrameSizeError(
+ "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
+ print >> sys.stderr, "WARNING: This looks like an 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, 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.')
+
+ if self.stream_dependency == 0x0:
+ raise ValueError('stream dependency is invalid.')
+
+ 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 = utils.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 xrange(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 Szie 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,
+}
generated by cgit v1.2.3 (git 2.25.1) at 2025-04-16 07:18:59 +0000