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| 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 "net/http2/decoder/payload_decoders/push_promise_payload_decoder.h" |
| 6 |
| 7 #include <stddef.h> |
| 8 |
| 9 #include "base/logging.h" |
| 10 #include "base/macros.h" |
| 11 #include "net/http2/decoder/decode_buffer.h" |
| 12 #include "net/http2/decoder/http2_frame_decoder_listener.h" |
| 13 #include "net/http2/http2_constants.h" |
| 14 #include "net/http2/http2_structures.h" |
| 15 #include "net/http2/tools/http2_bug_tracker.h" |
| 16 |
| 17 namespace net { |
| 18 |
| 19 std::ostream& operator<<(std::ostream& out, |
| 20 PushPromisePayloadDecoder::PayloadState v) { |
| 21 switch (v) { |
| 22 case PushPromisePayloadDecoder::PayloadState::kReadPadLength: |
| 23 return out << "kReadPadLength"; |
| 24 case PushPromisePayloadDecoder::PayloadState:: |
| 25 kStartDecodingPushPromiseFields: |
| 26 return out << "kStartDecodingPushPromiseFields"; |
| 27 case PushPromisePayloadDecoder::PayloadState::kReadPayload: |
| 28 return out << "kReadPayload"; |
| 29 case PushPromisePayloadDecoder::PayloadState::kSkipPadding: |
| 30 return out << "kSkipPadding"; |
| 31 case PushPromisePayloadDecoder::PayloadState:: |
| 32 kResumeDecodingPushPromiseFields: |
| 33 return out << "kResumeDecodingPushPromiseFields"; |
| 34 } |
| 35 return out << static_cast<int>(v); |
| 36 } |
| 37 |
| 38 DecodeStatus PushPromisePayloadDecoder::StartDecodingPayload( |
| 39 FrameDecoderState* state, |
| 40 DecodeBuffer* db) { |
| 41 const Http2FrameHeader& frame_header = state->frame_header(); |
| 42 const uint32_t total_length = frame_header.payload_length; |
| 43 |
| 44 DVLOG(2) << "PushPromisePayloadDecoder::StartDecodingPayload: " |
| 45 << frame_header; |
| 46 |
| 47 DCHECK_EQ(Http2FrameType::PUSH_PROMISE, frame_header.type); |
| 48 DCHECK_LE(db->Remaining(), total_length); |
| 49 DCHECK_EQ( |
| 50 0, frame_header.flags & |
| 51 ~(Http2FrameFlag::FLAG_END_HEADERS | Http2FrameFlag::FLAG_PADDED)); |
| 52 |
| 53 if (!frame_header.IsPadded()) { |
| 54 // If it turns out that PUSH_PROMISE frames without padding are sufficiently |
| 55 // common, and that they are usually short enough that they fit entirely |
| 56 // into one DecodeBuffer, we can detect that here and implement a special |
| 57 // case, avoiding the state machine in ResumeDecodingPayload. |
| 58 payload_state_ = PayloadState::kStartDecodingPushPromiseFields; |
| 59 } else { |
| 60 payload_state_ = PayloadState::kReadPadLength; |
| 61 } |
| 62 state->InitializeRemainders(); |
| 63 return ResumeDecodingPayload(state, db); |
| 64 } |
| 65 |
| 66 DecodeStatus PushPromisePayloadDecoder::ResumeDecodingPayload( |
| 67 FrameDecoderState* state, |
| 68 DecodeBuffer* db) { |
| 69 DVLOG(2) << "UnknownPayloadDecoder::ResumeDecodingPayload" |
| 70 << " remaining_payload=" << state->remaining_payload() |
| 71 << " db->Remaining=" << db->Remaining(); |
| 72 |
| 73 const Http2FrameHeader& frame_header = state->frame_header(); |
| 74 DCHECK_EQ(Http2FrameType::PUSH_PROMISE, frame_header.type); |
| 75 DCHECK_LE(state->remaining_payload(), frame_header.payload_length); |
| 76 DCHECK_LE(db->Remaining(), frame_header.payload_length); |
| 77 |
| 78 DecodeStatus status; |
| 79 while (true) { |
| 80 DVLOG(2) |
| 81 << "PushPromisePayloadDecoder::ResumeDecodingPayload payload_state_=" |
| 82 << payload_state_; |
| 83 switch (payload_state_) { |
| 84 case PayloadState::kReadPadLength: |
| 85 DCHECK_EQ(state->remaining_payload(), frame_header.payload_length); |
| 86 // ReadPadLength handles the OnPadLength callback, and updating the |
| 87 // remaining_payload and remaining_padding fields. If the amount of |
| 88 // padding is too large to fit in the frame's payload, ReadPadLength |
| 89 // instead calls OnPaddingTooLong and returns kDecodeError. |
| 90 // Suppress the call to OnPadLength because we haven't yet called |
| 91 // OnPushPromiseStart, which needs to wait until we've decoded the |
| 92 // Promised Stream ID. |
| 93 status = state->ReadPadLength(db, /*report_pad_length*/ false); |
| 94 if (status != DecodeStatus::kDecodeDone) { |
| 95 payload_state_ = PayloadState::kReadPadLength; |
| 96 return status; |
| 97 } |
| 98 // FALLTHROUGH_INTENDED |
| 99 |
| 100 case PayloadState::kStartDecodingPushPromiseFields: |
| 101 status = |
| 102 state->StartDecodingStructureInPayload(&push_promise_fields_, db); |
| 103 if (status != DecodeStatus::kDecodeDone) { |
| 104 payload_state_ = PayloadState::kResumeDecodingPushPromiseFields; |
| 105 return status; |
| 106 } |
| 107 // Finished decoding the Promised Stream ID. Can now tell the listener |
| 108 // that we're starting to decode a PUSH_PROMISE frame. |
| 109 ReportPushPromise(state); |
| 110 // FALLTHROUGH_INTENDED |
| 111 |
| 112 case PayloadState::kReadPayload: |
| 113 DCHECK_LT(state->remaining_payload(), frame_header.payload_length); |
| 114 DCHECK_LE(state->remaining_payload(), |
| 115 frame_header.payload_length - |
| 116 Http2PushPromiseFields::EncodedSize()); |
| 117 DCHECK_LE( |
| 118 state->remaining_payload(), |
| 119 frame_header.payload_length - |
| 120 Http2PushPromiseFields::EncodedSize() - |
| 121 (frame_header.IsPadded() ? (1 + state->remaining_padding()) |
| 122 : 0)); |
| 123 { |
| 124 size_t avail = state->AvailablePayload(db); |
| 125 state->listener()->OnHpackFragment(db->cursor(), avail); |
| 126 db->AdvanceCursor(avail); |
| 127 state->ConsumePayload(avail); |
| 128 } |
| 129 if (state->remaining_payload() > 0) { |
| 130 payload_state_ = PayloadState::kReadPayload; |
| 131 return DecodeStatus::kDecodeInProgress; |
| 132 } |
| 133 // FALLTHROUGH_INTENDED |
| 134 |
| 135 case PayloadState::kSkipPadding: |
| 136 // SkipPadding handles the OnPadding callback. |
| 137 if (state->SkipPadding(db)) { |
| 138 state->listener()->OnPushPromiseEnd(); |
| 139 return DecodeStatus::kDecodeDone; |
| 140 } |
| 141 payload_state_ = PayloadState::kSkipPadding; |
| 142 return DecodeStatus::kDecodeInProgress; |
| 143 |
| 144 case PayloadState::kResumeDecodingPushPromiseFields: |
| 145 status = |
| 146 state->ResumeDecodingStructureInPayload(&push_promise_fields_, db); |
| 147 if (status == DecodeStatus::kDecodeDone) { |
| 148 // Finished decoding the Promised Stream ID. Can now tell the listener |
| 149 // that we're starting to decode a PUSH_PROMISE frame. |
| 150 ReportPushPromise(state); |
| 151 payload_state_ = PayloadState::kReadPayload; |
| 152 continue; |
| 153 } |
| 154 payload_state_ = PayloadState::kResumeDecodingPushPromiseFields; |
| 155 return status; |
| 156 } |
| 157 HTTP2_BUG << "PayloadState: " << payload_state_; |
| 158 } |
| 159 } |
| 160 |
| 161 void PushPromisePayloadDecoder::ReportPushPromise(FrameDecoderState* state) { |
| 162 const Http2FrameHeader& frame_header = state->frame_header(); |
| 163 if (frame_header.IsPadded()) { |
| 164 state->listener()->OnPushPromiseStart(frame_header, push_promise_fields_, |
| 165 1 + state->remaining_padding()); |
| 166 } else { |
| 167 state->listener()->OnPushPromiseStart(frame_header, push_promise_fields_, |
| 168 0); |
| 169 } |
| 170 } |
| 171 |
| 172 } // namespace net |
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