| // 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/ping_payload_decoder.h" |
| |
| #include "http2/decoder/http2_frame_decoder_listener.h" |
| #include "http2/http2_constants.h" |
| #include "http2/platform/api/http2_logging.h" |
| |
| namespace http2 { |
| namespace { |
| constexpr auto kOpaqueSize = Http2PingFields::EncodedSize(); |
| } |
| |
| DecodeStatus PingPayloadDecoder::StartDecodingPayload(FrameDecoderState* state, |
| DecodeBuffer* db) { |
| const Http2FrameHeader& frame_header = state->frame_header(); |
| const uint32_t total_length = frame_header.payload_length; |
| |
| HTTP2_DVLOG(2) << "PingPayloadDecoder::StartDecodingPayload: " |
| << frame_header; |
| QUICHE_DCHECK_EQ(Http2FrameType::PING, frame_header.type); |
| QUICHE_DCHECK_LE(db->Remaining(), total_length); |
| QUICHE_DCHECK_EQ(0, frame_header.flags & ~(Http2FrameFlag::ACK)); |
| |
| // Is the payload entirely in the decode buffer and is it the correct size? |
| // Given the size of the header and payload (17 bytes total), this is most |
| // likely the case the vast majority of the time. |
| if (db->Remaining() == kOpaqueSize && total_length == kOpaqueSize) { |
| // Special case this situation as it allows us to avoid any copying; |
| // the other path makes two copies, first into the buffer in |
| // Http2StructureDecoder as it accumulates the 8 bytes of opaque data, |
| // and a second copy into the Http2PingFields member of in this class. |
| // This supports the claim that this decoder is (mostly) non-buffering. |
| static_assert(sizeof(Http2PingFields) == kOpaqueSize, |
| "If not, then can't enter this block!"); |
| auto* ping = reinterpret_cast<const Http2PingFields*>(db->cursor()); |
| if (frame_header.IsAck()) { |
| state->listener()->OnPingAck(frame_header, *ping); |
| } else { |
| state->listener()->OnPing(frame_header, *ping); |
| } |
| db->AdvanceCursor(kOpaqueSize); |
| return DecodeStatus::kDecodeDone; |
| } |
| state->InitializeRemainders(); |
| return HandleStatus( |
| state, state->StartDecodingStructureInPayload(&ping_fields_, db)); |
| } |
| |
| DecodeStatus PingPayloadDecoder::ResumeDecodingPayload(FrameDecoderState* state, |
| DecodeBuffer* db) { |
| HTTP2_DVLOG(2) << "ResumeDecodingPayload: remaining_payload=" |
| << state->remaining_payload(); |
| QUICHE_DCHECK_EQ(Http2FrameType::PING, state->frame_header().type); |
| QUICHE_DCHECK_LE(db->Remaining(), state->frame_header().payload_length); |
| return HandleStatus( |
| state, state->ResumeDecodingStructureInPayload(&ping_fields_, db)); |
| } |
| |
| DecodeStatus PingPayloadDecoder::HandleStatus(FrameDecoderState* state, |
| DecodeStatus status) { |
| HTTP2_DVLOG(2) << "HandleStatus: status=" << status |
| << "; remaining_payload=" << state->remaining_payload(); |
| if (status == DecodeStatus::kDecodeDone) { |
| if (state->remaining_payload() == 0) { |
| const Http2FrameHeader& frame_header = state->frame_header(); |
| if (frame_header.IsAck()) { |
| state->listener()->OnPingAck(frame_header, ping_fields_); |
| } else { |
| state->listener()->OnPing(frame_header, ping_fields_); |
| } |
| return DecodeStatus::kDecodeDone; |
| } |
| // Payload is too long. |
| return state->ReportFrameSizeError(); |
| } |
| // Not done decoding the structure. Either we've got more payload to decode, |
| // or we've run out because the payload is too short. |
| QUICHE_DCHECK( |
| (status == DecodeStatus::kDecodeInProgress && |
| state->remaining_payload() > 0) || |
| (status == DecodeStatus::kDecodeError && state->remaining_payload() == 0)) |
| << "\n status=" << status |
| << "; remaining_payload=" << state->remaining_payload(); |
| return status; |
| } |
| |
| } // namespace http2 |