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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/ping_payload_decoder.h" | |
6 | |
7 #include "base/logging.h" | |
8 #include "net/http2/decoder/http2_frame_decoder_listener.h" | |
9 #include "net/http2/http2_constants.h" | |
10 | |
11 namespace net { | |
12 namespace { | |
13 constexpr auto kOpaqueSize = Http2PingFields::EncodedSize(); | |
14 } | |
15 | |
16 DecodeStatus PingPayloadDecoder::StartDecodingPayload(FrameDecoderState* state, | |
17 DecodeBuffer* db) { | |
18 const Http2FrameHeader& frame_header = state->frame_header(); | |
19 const uint32_t total_length = frame_header.payload_length; | |
20 | |
21 DVLOG(2) << "PingPayloadDecoder::StartDecodingPayload: " << frame_header; | |
22 DCHECK_EQ(Http2FrameType::PING, frame_header.type); | |
23 DCHECK_LE(db->Remaining(), total_length); | |
24 DCHECK_EQ(0, frame_header.flags & ~(Http2FrameFlag::FLAG_ACK)); | |
25 | |
26 // Is the payload entirely in the decode buffer and is it the correct size? | |
27 // Given the size of the header and payload (17 bytes total), this is most | |
28 // likely the case the vast majority of the time. | |
29 if (db->Remaining() == kOpaqueSize && total_length == kOpaqueSize) { | |
30 // Special case this situation as it allows us to avoid any copying; | |
31 // the other path makes two copies, first into the buffer in | |
32 // Http2StructureDecoder as it accumulates the 8 bytes of opaque data, | |
33 // and a second copy into the Http2PingFields member of in this class. | |
34 // This supports the claim that this decoder is (mostly) non-buffering. | |
35 static_assert(sizeof(Http2PingFields) == kOpaqueSize, | |
36 "If not, then can't enter this block!"); | |
37 auto ping = reinterpret_cast<const Http2PingFields*>(db->cursor()); | |
38 if (frame_header.IsAck()) { | |
39 state->listener()->OnPingAck(frame_header, *ping); | |
40 } else { | |
41 state->listener()->OnPing(frame_header, *ping); | |
42 } | |
43 db->AdvanceCursor(kOpaqueSize); | |
44 return DecodeStatus::kDecodeDone; | |
45 } | |
46 state->InitializeRemainders(); | |
47 return HandleStatus( | |
48 state, state->StartDecodingStructureInPayload(&ping_fields_, db)); | |
49 } | |
50 | |
51 DecodeStatus PingPayloadDecoder::ResumeDecodingPayload(FrameDecoderState* state, | |
52 DecodeBuffer* db) { | |
53 DVLOG(2) << "ResumeDecodingPayload: remaining_payload=" | |
54 << state->remaining_payload(); | |
55 DCHECK_EQ(Http2FrameType::PING, state->frame_header().type); | |
56 DCHECK_LE(db->Remaining(), state->frame_header().payload_length); | |
57 return HandleStatus( | |
58 state, state->ResumeDecodingStructureInPayload(&ping_fields_, db)); | |
59 } | |
60 | |
61 DecodeStatus PingPayloadDecoder::HandleStatus(FrameDecoderState* state, | |
62 DecodeStatus status) { | |
63 DVLOG(2) << "HandleStatus: status=" << status | |
64 << "; remaining_payload=" << state->remaining_payload(); | |
65 if (status == DecodeStatus::kDecodeDone) { | |
66 if (state->remaining_payload() == 0) { | |
67 const Http2FrameHeader& frame_header = state->frame_header(); | |
68 if (frame_header.IsAck()) { | |
69 state->listener()->OnPingAck(frame_header, ping_fields_); | |
70 } else { | |
71 state->listener()->OnPing(frame_header, ping_fields_); | |
72 } | |
73 return DecodeStatus::kDecodeDone; | |
74 } | |
75 // Payload is too long. | |
76 return state->ReportFrameSizeError(); | |
77 } | |
78 // Not done decoding the structure. Either we've got more payload to decode, | |
79 // or we've run out because the payload is too short. | |
80 DCHECK( | |
81 (status == DecodeStatus::kDecodeInProgress && | |
82 state->remaining_payload() > 0) || | |
83 (status == DecodeStatus::kDecodeError && state->remaining_payload() == 0)) | |
84 << "\n status=" << status | |
85 << "; remaining_payload=" << state->remaining_payload(); | |
86 return status; | |
87 } | |
88 | |
89 } // namespace net | |
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