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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/headers_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 HeadersPayloadDecoder::PayloadState v) { | |
21 switch (v) { | |
22 case HeadersPayloadDecoder::PayloadState::kReadPadLength: | |
23 return out << "kReadPadLength"; | |
24 case HeadersPayloadDecoder::PayloadState::kStartDecodingPriorityFields: | |
25 return out << "kStartDecodingPriorityFields"; | |
26 case HeadersPayloadDecoder::PayloadState::kResumeDecodingPriorityFields: | |
27 return out << "kResumeDecodingPriorityFields"; | |
28 case HeadersPayloadDecoder::PayloadState::kReadPayload: | |
29 return out << "kReadPayload"; | |
30 case HeadersPayloadDecoder::PayloadState::kSkipPadding: | |
31 return out << "kSkipPadding"; | |
32 } | |
33 return out << static_cast<int>(v); | |
34 } | |
35 | |
36 DecodeStatus HeadersPayloadDecoder::StartDecodingPayload( | |
37 FrameDecoderState* state, | |
38 DecodeBuffer* db) { | |
39 const Http2FrameHeader& frame_header = state->frame_header(); | |
40 const uint32_t total_length = frame_header.payload_length; | |
41 | |
42 DVLOG(2) << "HeadersPayloadDecoder::StartDecodingPayload: " << frame_header; | |
43 | |
44 DCHECK_EQ(Http2FrameType::HEADERS, frame_header.type); | |
45 DCHECK_LE(db->Remaining(), total_length); | |
46 DCHECK_EQ( | |
47 0, | |
48 frame_header.flags & | |
49 ~(Http2FrameFlag::FLAG_END_STREAM | Http2FrameFlag::FLAG_END_HEADERS | | |
50 Http2FrameFlag::FLAG_PADDED | Http2FrameFlag::FLAG_PRIORITY)); | |
51 | |
52 // Special case for HEADERS frames that contain only the HPACK block | |
53 // (fragment or whole) and that fit fully into the decode buffer. | |
54 // Why? Unencoded browser GET requests are typically under 1K and HPACK | |
55 // commonly shrinks request headers by 80%, so we can expect this to | |
56 // be common. | |
57 // TODO(jamessynge) Add counters here and to Spdy for determining how | |
58 // common this situation is. A possible approach is to create a | |
59 // Http2FrameDecoderListener that counts the callbacks and then forwards | |
60 // them on to another listener, which makes it easy to add and remove | |
61 // counting on a connection or even frame basis. | |
62 | |
63 // PADDED and PRIORITY both extra steps to decode, but if neither flag is | |
64 // set then we can decode faster. | |
65 const auto payload_flags = | |
66 Http2FrameFlag::FLAG_PADDED | Http2FrameFlag::FLAG_PRIORITY; | |
67 if (!frame_header.HasAnyFlags(payload_flags)) { | |
68 DVLOG(2) << "StartDecodingPayload !IsPadded && !HasPriority"; | |
69 if (db->Remaining() == total_length) { | |
70 DVLOG(2) << "StartDecodingPayload all present"; | |
71 // Note that we don't cache the listener field so that the callee can | |
72 // replace it if the frame is bad. | |
73 // If this case is common enough, consider combining the 3 callbacks | |
74 // into one, especially if END_HEADERS is also set. | |
75 state->listener()->OnHeadersStart(frame_header); | |
76 if (total_length > 0) { | |
77 state->listener()->OnHpackFragment(db->cursor(), total_length); | |
78 db->AdvanceCursor(total_length); | |
79 } | |
80 state->listener()->OnHeadersEnd(); | |
81 return DecodeStatus::kDecodeDone; | |
82 } | |
83 payload_state_ = PayloadState::kReadPayload; | |
84 } else if (frame_header.IsPadded()) { | |
85 payload_state_ = PayloadState::kReadPadLength; | |
86 } else { | |
87 DCHECK(frame_header.HasPriority()) << frame_header; | |
88 payload_state_ = PayloadState::kStartDecodingPriorityFields; | |
89 } | |
90 state->InitializeRemainders(); | |
91 state->listener()->OnHeadersStart(frame_header); | |
92 return ResumeDecodingPayload(state, db); | |
93 } | |
94 | |
95 DecodeStatus HeadersPayloadDecoder::ResumeDecodingPayload( | |
96 FrameDecoderState* state, | |
97 DecodeBuffer* db) { | |
98 DVLOG(2) << "HeadersPayloadDecoder::ResumeDecodingPayload " | |
99 << "remaining_payload=" << state->remaining_payload() | |
100 << "; db->Remaining=" << db->Remaining(); | |
101 | |
102 const Http2FrameHeader& frame_header = state->frame_header(); | |
103 | |
104 DCHECK_EQ(Http2FrameType::HEADERS, frame_header.type); | |
105 DCHECK_LE(state->remaining_payload_and_padding(), | |
106 frame_header.payload_length); | |
107 DCHECK_LE(db->Remaining(), state->remaining_payload_and_padding()); | |
108 DecodeStatus status; | |
109 size_t avail; | |
110 while (true) { | |
111 DVLOG(2) << "HeadersPayloadDecoder::ResumeDecodingPayload payload_state_=" | |
112 << payload_state_; | |
113 switch (payload_state_) { | |
114 case PayloadState::kReadPadLength: | |
115 // ReadPadLength handles the OnPadLength callback, and updating the | |
116 // remaining_payload and remaining_padding fields. If the amount of | |
117 // padding is too large to fit in the frame's payload, ReadPadLength | |
118 // instead calls OnPaddingTooLong and returns kDecodeError. | |
119 status = state->ReadPadLength(db, /*report_pad_length*/ true); | |
120 if (status != DecodeStatus::kDecodeDone) { | |
121 return status; | |
122 } | |
123 if (!frame_header.HasPriority()) { | |
124 payload_state_ = PayloadState::kReadPayload; | |
125 continue; | |
126 } | |
127 // FALLTHROUGH_INTENDED | |
128 | |
129 case PayloadState::kStartDecodingPriorityFields: | |
130 status = state->StartDecodingStructureInPayload(&priority_fields_, db); | |
131 if (status != DecodeStatus::kDecodeDone) { | |
132 payload_state_ = PayloadState::kResumeDecodingPriorityFields; | |
133 return status; | |
134 } | |
135 state->listener()->OnHeadersPriority(priority_fields_); | |
136 // FALLTHROUGH_INTENDED | |
137 | |
138 case PayloadState::kReadPayload: | |
139 avail = state->AvailablePayload(db); | |
140 if (avail > 0) { | |
141 state->listener()->OnHpackFragment(db->cursor(), avail); | |
142 db->AdvanceCursor(avail); | |
143 state->ConsumePayload(avail); | |
144 } | |
145 if (state->remaining_payload() > 0) { | |
146 payload_state_ = PayloadState::kReadPayload; | |
147 return DecodeStatus::kDecodeInProgress; | |
148 } | |
149 // FALLTHROUGH_INTENDED | |
150 | |
151 case PayloadState::kSkipPadding: | |
152 // SkipPadding handles the OnPadding callback. | |
153 if (state->SkipPadding(db)) { | |
154 state->listener()->OnHeadersEnd(); | |
155 return DecodeStatus::kDecodeDone; | |
156 } | |
157 payload_state_ = PayloadState::kSkipPadding; | |
158 return DecodeStatus::kDecodeInProgress; | |
159 | |
160 case PayloadState::kResumeDecodingPriorityFields: | |
161 status = state->ResumeDecodingStructureInPayload(&priority_fields_, db); | |
162 if (status != DecodeStatus::kDecodeDone) { | |
163 return status; | |
164 } | |
165 state->listener()->OnHeadersPriority(priority_fields_); | |
166 payload_state_ = PayloadState::kReadPayload; | |
167 continue; | |
168 } | |
169 HTTP2_BUG << "PayloadState: " << payload_state_; | |
170 } | |
171 } | |
172 | |
173 } // namespace net | |
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