blob: f95417c6fe809471040bf7629011436f2adf7f3e [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/altsvc_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,
AltSvcPayloadDecoder::PayloadState v) {
switch (v) {
case AltSvcPayloadDecoder::PayloadState::kStartDecodingStruct:
return out << "kStartDecodingStruct";
case AltSvcPayloadDecoder::PayloadState::kMaybeDecodedStruct:
return out << "kMaybeDecodedStruct";
case AltSvcPayloadDecoder::PayloadState::kDecodingStrings:
return out << "kDecodingStrings";
case AltSvcPayloadDecoder::PayloadState::kResumeDecodingStruct:
return out << "kResumeDecodingStruct";
}
// 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_163_1)
<< "Invalid AltSvcPayloadDecoder::PayloadState: " << unknown;
return out << "AltSvcPayloadDecoder::PayloadState(" << unknown << ")";
}
DecodeStatus AltSvcPayloadDecoder::StartDecodingPayload(
FrameDecoderState* state,
DecodeBuffer* db) {
HTTP2_DVLOG(2) << "AltSvcPayloadDecoder::StartDecodingPayload: "
<< state->frame_header();
QUICHE_DCHECK_EQ(Http2FrameType::ALTSVC, state->frame_header().type);
QUICHE_DCHECK_LE(db->Remaining(), state->frame_header().payload_length);
QUICHE_DCHECK_EQ(0, state->frame_header().flags);
state->InitializeRemainders();
payload_state_ = PayloadState::kStartDecodingStruct;
return ResumeDecodingPayload(state, db);
}
DecodeStatus AltSvcPayloadDecoder::ResumeDecodingPayload(
FrameDecoderState* state,
DecodeBuffer* db) {
const Http2FrameHeader& frame_header = state->frame_header();
HTTP2_DVLOG(2) << "AltSvcPayloadDecoder::ResumeDecodingPayload: "
<< frame_header;
QUICHE_DCHECK_EQ(Http2FrameType::ALTSVC, frame_header.type);
QUICHE_DCHECK_LE(state->remaining_payload(), frame_header.payload_length);
QUICHE_DCHECK_LE(db->Remaining(), state->remaining_payload());
QUICHE_DCHECK_NE(PayloadState::kMaybeDecodedStruct, payload_state_);
// |status| has to be initialized to some value to avoid compiler error in
// case PayloadState::kMaybeDecodedStruct below, but value does not matter,
// see QUICHE_DCHECK_NE above.
DecodeStatus status = DecodeStatus::kDecodeError;
while (true) {
HTTP2_DVLOG(2)
<< "AltSvcPayloadDecoder::ResumeDecodingPayload payload_state_="
<< payload_state_;
switch (payload_state_) {
case PayloadState::kStartDecodingStruct:
status = state->StartDecodingStructureInPayload(&altsvc_fields_, db);
ABSL_FALLTHROUGH_INTENDED;
case PayloadState::kMaybeDecodedStruct:
if (status == DecodeStatus::kDecodeDone &&
altsvc_fields_.origin_length <= state->remaining_payload()) {
size_t origin_length = altsvc_fields_.origin_length;
size_t value_length = state->remaining_payload() - origin_length;
state->listener()->OnAltSvcStart(frame_header, origin_length,
value_length);
} else if (status != DecodeStatus::kDecodeDone) {
QUICHE_DCHECK(state->remaining_payload() > 0 ||
status == DecodeStatus::kDecodeError)
<< "\nremaining_payload: " << state->remaining_payload()
<< "\nstatus: " << status << "\nheader: " << frame_header;
// Assume in progress.
payload_state_ = PayloadState::kResumeDecodingStruct;
return status;
} else {
// The origin's length is longer than the remaining payload.
QUICHE_DCHECK_GT(altsvc_fields_.origin_length,
state->remaining_payload());
return state->ReportFrameSizeError();
}
ABSL_FALLTHROUGH_INTENDED;
case PayloadState::kDecodingStrings:
return DecodeStrings(state, db);
case PayloadState::kResumeDecodingStruct:
status = state->ResumeDecodingStructureInPayload(&altsvc_fields_, db);
payload_state_ = PayloadState::kMaybeDecodedStruct;
continue;
}
HTTP2_BUG(http2_bug_163_2) << "PayloadState: " << payload_state_;
}
}
DecodeStatus AltSvcPayloadDecoder::DecodeStrings(FrameDecoderState* state,
DecodeBuffer* db) {
HTTP2_DVLOG(2) << "AltSvcPayloadDecoder::DecodeStrings remaining_payload="
<< state->remaining_payload()
<< ", db->Remaining=" << db->Remaining();
// Note that we don't explicitly keep track of exactly how far through the
// origin; instead we compute it from how much is left of the original
// payload length and the decoded total length of the origin.
size_t origin_length = altsvc_fields_.origin_length;
size_t value_length = state->frame_header().payload_length - origin_length -
Http2AltSvcFields::EncodedSize();
if (state->remaining_payload() > value_length) {
size_t remaining_origin_length = state->remaining_payload() - value_length;
size_t avail = db->MinLengthRemaining(remaining_origin_length);
state->listener()->OnAltSvcOriginData(db->cursor(), avail);
db->AdvanceCursor(avail);
state->ConsumePayload(avail);
if (remaining_origin_length > avail) {
payload_state_ = PayloadState::kDecodingStrings;
return DecodeStatus::kDecodeInProgress;
}
}
// All that is left is the value string.
QUICHE_DCHECK_LE(state->remaining_payload(), value_length);
QUICHE_DCHECK_LE(db->Remaining(), state->remaining_payload());
if (db->HasData()) {
size_t avail = db->Remaining();
state->listener()->OnAltSvcValueData(db->cursor(), avail);
db->AdvanceCursor(avail);
state->ConsumePayload(avail);
}
if (state->remaining_payload() == 0) {
state->listener()->OnAltSvcEnd();
return DecodeStatus::kDecodeDone;
}
payload_state_ = PayloadState::kDecodingStrings;
return DecodeStatus::kDecodeInProgress;
}
} // namespace http2