blob: 9c637f96c76ae33d1cfc85d0e8350ba91923f415 [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.
#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;
DCHECK_EQ(Http2FrameType::PING, frame_header.type);
DCHECK_LE(db->Remaining(), total_length);
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();
DCHECK_EQ(Http2FrameType::PING, state->frame_header().type);
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.
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