blob: 295a0b04c7f505a8bafedd5a68c34256d15a4b50 [file] [log] [blame]
// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Http2FrameDecoder decodes the available input until it reaches the end of
// the input or it reaches the end of the first frame in the input.
// Note that Http2FrameDecoder does only minimal validation; for example,
// stream ids are not checked, nor is the sequence of frames such as
// CONTINUATION frame placement.
// Http2FrameDecoder enters state kError once it has called the listener's
// OnFrameSizeError or OnPaddingTooLong methods, and at this time has no
// provision for leaving that state. While the HTTP/2 spec (RFC7540) allows
// for some such errors to be considered as just stream errors in some cases,
// this implementation treats them all as connection errors.
#include <stddef.h>
#include <cstdint>
#include "http2/decoder/decode_buffer.h"
#include "http2/decoder/decode_status.h"
#include "http2/decoder/frame_decoder_state.h"
#include "http2/decoder/http2_frame_decoder_listener.h"
#include "http2/decoder/payload_decoders/altsvc_payload_decoder.h"
#include "http2/decoder/payload_decoders/continuation_payload_decoder.h"
#include "http2/decoder/payload_decoders/data_payload_decoder.h"
#include "http2/decoder/payload_decoders/goaway_payload_decoder.h"
#include "http2/decoder/payload_decoders/headers_payload_decoder.h"
#include "http2/decoder/payload_decoders/ping_payload_decoder.h"
#include "http2/decoder/payload_decoders/priority_payload_decoder.h"
#include "http2/decoder/payload_decoders/priority_update_payload_decoder.h"
#include "http2/decoder/payload_decoders/push_promise_payload_decoder.h"
#include "http2/decoder/payload_decoders/rst_stream_payload_decoder.h"
#include "http2/decoder/payload_decoders/settings_payload_decoder.h"
#include "http2/decoder/payload_decoders/unknown_payload_decoder.h"
#include "http2/decoder/payload_decoders/window_update_payload_decoder.h"
#include "http2/http2_structures.h"
#include "http2/platform/api/http2_logging.h"
#include "common/platform/api/quiche_export.h"
namespace http2 {
namespace test {
class Http2FrameDecoderPeer;
} // namespace test
class QUICHE_EXPORT_PRIVATE Http2FrameDecoder {
explicit Http2FrameDecoder(Http2FrameDecoderListener* listener);
Http2FrameDecoder() : Http2FrameDecoder(nullptr) {}
Http2FrameDecoder(const Http2FrameDecoder&) = delete;
Http2FrameDecoder& operator=(const Http2FrameDecoder&) = delete;
// The decoder will call the listener's methods as it decodes a frame.
void set_listener(Http2FrameDecoderListener* listener);
Http2FrameDecoderListener* listener() const;
// The decoder will reject frame's whose payload
// length field exceeds the maximum payload size.
void set_maximum_payload_size(size_t v) { maximum_payload_size_ = v; }
size_t maximum_payload_size() const { return maximum_payload_size_; }
// Decodes the input up to the next frame boundary (i.e. at most one frame).
// Returns kDecodeDone if it decodes the final byte of a frame, OR if there
// is no input and it is awaiting the start of a new frame (e.g. if this
// is the first call to DecodeFrame, or if the previous call returned
// kDecodeDone).
// Returns kDecodeInProgress if it decodes all of the decode buffer, but has
// not reached the end of the frame.
// Returns kDecodeError if the frame's padding or length wasn't valid (i.e. if
// the decoder called either the listener's OnPaddingTooLong or
// OnFrameSizeError method).
// If the decode buffer contains the entirety of a frame payload or field,
// then the corresponding Http2FrameDecoderListener::On*Payload(),
// OnHpackFragment(), OnGoAwayOpaqueData(), or OnAltSvcValueData() method is
// guaranteed to be called exactly once, with the entire payload or field in a
// single chunk.
DecodeStatus DecodeFrame(DecodeBuffer* db);
// Methods that support Http2FrameDecoderAdapter.
// Is the remainder of the frame's payload being discarded?
bool IsDiscardingPayload() const { return state_ == State::kDiscardPayload; }
// Returns the number of bytes of the frame's payload that remain to be
// decoded, excluding any trailing padding. This method must only be called
// after the frame header has been decoded AND DecodeFrame has returned
// kDecodeInProgress.
size_t remaining_payload() const;
// Returns the number of bytes of trailing padding after the payload that
// remain to be decoded. This method must only be called if the frame type
// allows padding, and after the frame header has been decoded AND
// DecodeFrame has returned. Will return 0 if the Pad Length field has not
// yet been decoded.
uint32_t remaining_padding() const;
enum class State {
// Ready to start decoding a new frame's header.
// Was in state kStartDecodingHeader, but unable to read the entire frame
// header, so needs more input to complete decoding the header.
// Have decoded the frame header, and started decoding the available bytes
// of the frame's payload, but need more bytes to finish the job.
// Decoding of the most recently started frame resulted in an error:
// OnPaddingTooLong or OnFrameSizeError was called to indicate that the
// decoder detected a problem, or OnFrameHeader returned false, indicating
// that the listener detected a problem. Regardless of which, the decoder
// will stay in state kDiscardPayload until it has been passed the rest
// of the bytes of the frame's payload that it hasn't yet seen, after
// which it will be ready to decode another frame.
friend class test::Http2FrameDecoderPeer;
friend std::ostream& operator<<(std::ostream& out, State v);
DecodeStatus StartDecodingPayload(DecodeBuffer* db);
DecodeStatus ResumeDecodingPayload(DecodeBuffer* db);
DecodeStatus DiscardPayload(DecodeBuffer* db);
const Http2FrameHeader& frame_header() const {
return frame_decoder_state_.frame_header();
// Clear any of the flags in the frame header that aren't set in valid_flags.
void RetainFlags(uint8_t valid_flags);
// Clear all of the flags in the frame header; for use with frame types that
// don't define any flags, such as WINDOW_UPDATE.
void ClearFlags();
// These methods call the StartDecodingPayload() method of the frame type's
// payload decoder, after first clearing invalid flags in the header. The
// caller must ensure that the decode buffer does not extend beyond the
// end of the payload (handled by Http2FrameDecoder::StartDecodingPayload).
DecodeStatus StartDecodingAltSvcPayload(DecodeBuffer* db);
DecodeStatus StartDecodingContinuationPayload(DecodeBuffer* db);
DecodeStatus StartDecodingDataPayload(DecodeBuffer* db);
DecodeStatus StartDecodingGoAwayPayload(DecodeBuffer* db);
DecodeStatus StartDecodingHeadersPayload(DecodeBuffer* db);
DecodeStatus StartDecodingPingPayload(DecodeBuffer* db);
DecodeStatus StartDecodingPriorityPayload(DecodeBuffer* db);
DecodeStatus StartDecodingPriorityUpdatePayload(DecodeBuffer* db);
DecodeStatus StartDecodingPushPromisePayload(DecodeBuffer* db);
DecodeStatus StartDecodingRstStreamPayload(DecodeBuffer* db);
DecodeStatus StartDecodingSettingsPayload(DecodeBuffer* db);
DecodeStatus StartDecodingUnknownPayload(DecodeBuffer* db);
DecodeStatus StartDecodingWindowUpdatePayload(DecodeBuffer* db);
// These methods call the ResumeDecodingPayload() method of the frame type's
// payload decoder; they are called only if the preceding call to the
// corresponding Start method (above) returned kDecodeInProgress, as did any
// subsequent calls to the resume method.
// Unlike the Start methods, the decode buffer may extend beyond the
// end of the payload, so the method will create a DecodeBufferSubset
// before calling the ResumeDecodingPayload method of the frame type's
// payload decoder.
DecodeStatus ResumeDecodingAltSvcPayload(DecodeBuffer* db);
DecodeStatus ResumeDecodingContinuationPayload(DecodeBuffer* db);
DecodeStatus ResumeDecodingDataPayload(DecodeBuffer* db);
DecodeStatus ResumeDecodingGoAwayPayload(DecodeBuffer* db);
DecodeStatus ResumeDecodingHeadersPayload(DecodeBuffer* db);
DecodeStatus ResumeDecodingPingPayload(DecodeBuffer* db);
DecodeStatus ResumeDecodingPriorityPayload(DecodeBuffer* db);
DecodeStatus ResumeDecodingPriorityUpdatePayload(DecodeBuffer* db);
DecodeStatus ResumeDecodingPushPromisePayload(DecodeBuffer* db);
DecodeStatus ResumeDecodingRstStreamPayload(DecodeBuffer* db);
DecodeStatus ResumeDecodingSettingsPayload(DecodeBuffer* db);
DecodeStatus ResumeDecodingUnknownPayload(DecodeBuffer* db);
DecodeStatus ResumeDecodingWindowUpdatePayload(DecodeBuffer* db);
FrameDecoderState frame_decoder_state_;
// We only need one payload decoder at a time, so they share the same storage.
union {
AltSvcPayloadDecoder altsvc_payload_decoder_;
ContinuationPayloadDecoder continuation_payload_decoder_;
DataPayloadDecoder data_payload_decoder_;
GoAwayPayloadDecoder goaway_payload_decoder_;
HeadersPayloadDecoder headers_payload_decoder_;
PingPayloadDecoder ping_payload_decoder_;
PriorityPayloadDecoder priority_payload_decoder_;
PriorityUpdatePayloadDecoder priority_payload_update_decoder_;
PushPromisePayloadDecoder push_promise_payload_decoder_;
RstStreamPayloadDecoder rst_stream_payload_decoder_;
SettingsPayloadDecoder settings_payload_decoder_;
UnknownPayloadDecoder unknown_payload_decoder_;
WindowUpdatePayloadDecoder window_update_payload_decoder_;
State state_;
size_t maximum_payload_size_;
// Listener used whenever caller passes nullptr to set_listener.
Http2FrameDecoderNoOpListener no_op_listener_;
} // namespace http2