| // 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. |
| |
| #include "http2/decoder/payload_decoders/headers_payload_decoder.h" |
| |
| #include <stddef.h> |
| |
| #include "absl/base/macros.h" |
| #include "http2/decoder/decode_buffer.h" |
| #include "http2/decoder/http2_frame_decoder_listener.h" |
| #include "http2/http2_constants.h" |
| #include "http2/http2_structures.h" |
| #include "http2/platform/api/http2_bug_tracker.h" |
| #include "http2/platform/api/http2_logging.h" |
| |
| namespace http2 { |
| |
| std::ostream& operator<<(std::ostream& out, |
| HeadersPayloadDecoder::PayloadState v) { |
| switch (v) { |
| case HeadersPayloadDecoder::PayloadState::kReadPadLength: |
| return out << "kReadPadLength"; |
| case HeadersPayloadDecoder::PayloadState::kStartDecodingPriorityFields: |
| return out << "kStartDecodingPriorityFields"; |
| case HeadersPayloadDecoder::PayloadState::kResumeDecodingPriorityFields: |
| return out << "kResumeDecodingPriorityFields"; |
| case HeadersPayloadDecoder::PayloadState::kReadPayload: |
| return out << "kReadPayload"; |
| case HeadersPayloadDecoder::PayloadState::kSkipPadding: |
| return out << "kSkipPadding"; |
| } |
| // Since the value doesn't come over the wire, only a programming bug should |
| // result in reaching this point. |
| int unknown = static_cast<int>(v); |
| HTTP2_BUG(http2_bug_189_1) |
| << "Invalid HeadersPayloadDecoder::PayloadState: " << unknown; |
| return out << "HeadersPayloadDecoder::PayloadState(" << unknown << ")"; |
| } |
| |
| DecodeStatus HeadersPayloadDecoder::StartDecodingPayload( |
| FrameDecoderState* state, |
| DecodeBuffer* db) { |
| const Http2FrameHeader& frame_header = state->frame_header(); |
| const uint32_t total_length = frame_header.payload_length; |
| |
| HTTP2_DVLOG(2) << "HeadersPayloadDecoder::StartDecodingPayload: " |
| << frame_header; |
| |
| QUICHE_DCHECK_EQ(Http2FrameType::HEADERS, frame_header.type); |
| QUICHE_DCHECK_LE(db->Remaining(), total_length); |
| QUICHE_DCHECK_EQ( |
| 0, frame_header.flags & |
| ~(Http2FrameFlag::END_STREAM | Http2FrameFlag::END_HEADERS | |
| Http2FrameFlag::PADDED | Http2FrameFlag::PRIORITY)); |
| |
| // Special case for HEADERS frames that contain only the HPACK block |
| // (fragment or whole) and that fit fully into the decode buffer. |
| // Why? Unencoded browser GET requests are typically under 1K and HPACK |
| // commonly shrinks request headers by 80%, so we can expect this to |
| // be common. |
| // TODO(jamessynge) Add counters here and to Spdy for determining how |
| // common this situation is. A possible approach is to create a |
| // Http2FrameDecoderListener that counts the callbacks and then forwards |
| // them on to another listener, which makes it easy to add and remove |
| // counting on a connection or even frame basis. |
| |
| // PADDED and PRIORITY both extra steps to decode, but if neither flag is |
| // set then we can decode faster. |
| const auto payload_flags = Http2FrameFlag::PADDED | Http2FrameFlag::PRIORITY; |
| if (!frame_header.HasAnyFlags(payload_flags)) { |
| HTTP2_DVLOG(2) << "StartDecodingPayload !IsPadded && !HasPriority"; |
| if (db->Remaining() == total_length) { |
| HTTP2_DVLOG(2) << "StartDecodingPayload all present"; |
| // Note that we don't cache the listener field so that the callee can |
| // replace it if the frame is bad. |
| // If this case is common enough, consider combining the 3 callbacks |
| // into one, especially if END_HEADERS is also set. |
| state->listener()->OnHeadersStart(frame_header); |
| if (total_length > 0) { |
| state->listener()->OnHpackFragment(db->cursor(), total_length); |
| db->AdvanceCursor(total_length); |
| } |
| state->listener()->OnHeadersEnd(); |
| return DecodeStatus::kDecodeDone; |
| } |
| payload_state_ = PayloadState::kReadPayload; |
| } else if (frame_header.IsPadded()) { |
| payload_state_ = PayloadState::kReadPadLength; |
| } else { |
| QUICHE_DCHECK(frame_header.HasPriority()) << frame_header; |
| payload_state_ = PayloadState::kStartDecodingPriorityFields; |
| } |
| state->InitializeRemainders(); |
| state->listener()->OnHeadersStart(frame_header); |
| return ResumeDecodingPayload(state, db); |
| } |
| |
| DecodeStatus HeadersPayloadDecoder::ResumeDecodingPayload( |
| FrameDecoderState* state, |
| DecodeBuffer* db) { |
| HTTP2_DVLOG(2) << "HeadersPayloadDecoder::ResumeDecodingPayload " |
| << "remaining_payload=" << state->remaining_payload() |
| << "; db->Remaining=" << db->Remaining(); |
| |
| const Http2FrameHeader& frame_header = state->frame_header(); |
| |
| QUICHE_DCHECK_EQ(Http2FrameType::HEADERS, frame_header.type); |
| QUICHE_DCHECK_LE(state->remaining_payload_and_padding(), |
| frame_header.payload_length); |
| QUICHE_DCHECK_LE(db->Remaining(), state->remaining_payload_and_padding()); |
| DecodeStatus status; |
| size_t avail; |
| while (true) { |
| HTTP2_DVLOG(2) |
| << "HeadersPayloadDecoder::ResumeDecodingPayload payload_state_=" |
| << payload_state_; |
| switch (payload_state_) { |
| case PayloadState::kReadPadLength: |
| // ReadPadLength handles the OnPadLength callback, and updating the |
| // remaining_payload and remaining_padding fields. If the amount of |
| // padding is too large to fit in the frame's payload, ReadPadLength |
| // instead calls OnPaddingTooLong and returns kDecodeError. |
| status = state->ReadPadLength(db, /*report_pad_length*/ true); |
| if (status != DecodeStatus::kDecodeDone) { |
| return status; |
| } |
| if (!frame_header.HasPriority()) { |
| payload_state_ = PayloadState::kReadPayload; |
| continue; |
| } |
| ABSL_FALLTHROUGH_INTENDED; |
| |
| case PayloadState::kStartDecodingPriorityFields: |
| status = state->StartDecodingStructureInPayload(&priority_fields_, db); |
| if (status != DecodeStatus::kDecodeDone) { |
| payload_state_ = PayloadState::kResumeDecodingPriorityFields; |
| return status; |
| } |
| state->listener()->OnHeadersPriority(priority_fields_); |
| ABSL_FALLTHROUGH_INTENDED; |
| |
| case PayloadState::kReadPayload: |
| avail = state->AvailablePayload(db); |
| if (avail > 0) { |
| state->listener()->OnHpackFragment(db->cursor(), avail); |
| db->AdvanceCursor(avail); |
| state->ConsumePayload(avail); |
| } |
| if (state->remaining_payload() > 0) { |
| payload_state_ = PayloadState::kReadPayload; |
| return DecodeStatus::kDecodeInProgress; |
| } |
| ABSL_FALLTHROUGH_INTENDED; |
| |
| case PayloadState::kSkipPadding: |
| // SkipPadding handles the OnPadding callback. |
| if (state->SkipPadding(db)) { |
| state->listener()->OnHeadersEnd(); |
| return DecodeStatus::kDecodeDone; |
| } |
| payload_state_ = PayloadState::kSkipPadding; |
| return DecodeStatus::kDecodeInProgress; |
| |
| case PayloadState::kResumeDecodingPriorityFields: |
| status = state->ResumeDecodingStructureInPayload(&priority_fields_, db); |
| if (status != DecodeStatus::kDecodeDone) { |
| return status; |
| } |
| state->listener()->OnHeadersPriority(priority_fields_); |
| payload_state_ = PayloadState::kReadPayload; |
| continue; |
| } |
| HTTP2_BUG(http2_bug_189_2) << "PayloadState: " << payload_state_; |
| } |
| } |
| |
| } // namespace http2 |