1 // Copyright 2016 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "quiche/http2/decoder/frame_decoder_state.h"
6
7 namespace http2 {
8
ReadPadLength(DecodeBuffer * db,bool report_pad_length)9 DecodeStatus FrameDecoderState::ReadPadLength(DecodeBuffer* db,
10 bool report_pad_length) {
11 QUICHE_DVLOG(2) << "ReadPadLength db->Remaining=" << db->Remaining()
12 << "; payload_length=" << frame_header().payload_length;
13 QUICHE_DCHECK(IsPaddable());
14 QUICHE_DCHECK(frame_header().IsPadded());
15
16 // Pad Length is always at the start of the frame, so remaining_payload_
17 // should equal payload_length at this point.
18 const uint32_t total_payload = frame_header().payload_length;
19 QUICHE_DCHECK_EQ(total_payload, remaining_payload_);
20 QUICHE_DCHECK_EQ(0u, remaining_padding_);
21
22 if (db->HasData()) {
23 const uint32_t pad_length = db->DecodeUInt8();
24 const uint32_t total_padding = pad_length + 1;
25 if (total_padding <= total_payload) {
26 remaining_padding_ = pad_length;
27 remaining_payload_ = total_payload - total_padding;
28 if (report_pad_length) {
29 listener()->OnPadLength(pad_length);
30 }
31 return DecodeStatus::kDecodeDone;
32 }
33 const uint32_t missing_length = total_padding - total_payload;
34 // To allow for the possibility of recovery, record the number of
35 // remaining bytes of the frame's payload (invalid though it is)
36 // in remaining_payload_.
37 remaining_payload_ = total_payload - 1; // 1 for sizeof(Pad Length).
38 remaining_padding_ = 0;
39 listener()->OnPaddingTooLong(frame_header(), missing_length);
40 return DecodeStatus::kDecodeError;
41 }
42
43 if (total_payload == 0) {
44 remaining_payload_ = 0;
45 remaining_padding_ = 0;
46 listener()->OnPaddingTooLong(frame_header(), 1);
47 return DecodeStatus::kDecodeError;
48 }
49 // Need to wait for another buffer.
50 return DecodeStatus::kDecodeInProgress;
51 }
52
SkipPadding(DecodeBuffer * db)53 bool FrameDecoderState::SkipPadding(DecodeBuffer* db) {
54 QUICHE_DVLOG(2) << "SkipPadding remaining_padding_=" << remaining_padding_
55 << ", db->Remaining=" << db->Remaining()
56 << ", header: " << frame_header();
57 QUICHE_DCHECK_EQ(remaining_payload_, 0u);
58 QUICHE_DCHECK(IsPaddable()) << "header: " << frame_header();
59 QUICHE_DCHECK(remaining_padding_ == 0 || frame_header().IsPadded())
60 << "remaining_padding_=" << remaining_padding_
61 << ", header: " << frame_header();
62 const size_t avail = AvailablePadding(db);
63 if (avail > 0) {
64 listener()->OnPadding(db->cursor(), avail);
65 db->AdvanceCursor(avail);
66 remaining_padding_ -= avail;
67 }
68 return remaining_padding_ == 0;
69 }
70
ReportFrameSizeError()71 DecodeStatus FrameDecoderState::ReportFrameSizeError() {
72 QUICHE_DVLOG(2) << "FrameDecoderState::ReportFrameSizeError: "
73 << " remaining_payload_=" << remaining_payload_
74 << "; remaining_padding_=" << remaining_padding_
75 << ", header: " << frame_header();
76 listener()->OnFrameSizeError(frame_header());
77 return DecodeStatus::kDecodeError;
78 }
79
80 } // namespace http2
81