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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 "base/metrics/histogram_macros.h" |
| 6 #include "net/filter/sdch_policy_delegate.h" |
| 7 #include "net/filter/sdch_stream_source.h" |
| 8 |
| 9 namespace { |
| 10 |
| 11 const char kRefreshHtml[] = |
| 12 "<head><META HTTP-EQUIV=\"Refresh\" CONTENT=\"0\"></head>"; |
| 13 |
| 14 // Measures the eventual fate of the stream handled by this delegate. |
| 15 enum StreamFate { |
| 16 STREAM_FATE_OK, |
| 17 STREAM_FATE_STOP_DECODING, |
| 18 STREAM_FATE_REFRESH, |
| 19 STREAM_FATE_FAIL |
| 20 }; |
| 21 |
| 22 // Causes for the fates given above. FATE_OK is always CAUSE_NONE. |
| 23 enum StreamFateCause { |
| 24 STREAM_FATE_CAUSE_NONE, |
| 25 STREAM_FATE_CAUSE_404, |
| 26 STREAM_FATE_CAUSE_NOT_200, |
| 27 STREAM_FATE_CAUSE_OLD_UNENCODED, |
| 28 STREAM_FATE_CAUSE_TENTATIVE_SDCH, |
| 29 STREAM_FATE_CAUSE_NO_DICTIONARY, |
| 30 STREAM_FATE_CAUSE_CORRUPT_SDCH, |
| 31 STREAM_FATE_CAUSE_ENCODING_LIE, |
| 32 STREAM_FATE_CAUSE_MAX |
| 33 }; |
| 34 |
| 35 } // namespace |
| 36 |
| 37 namespace net { |
| 38 |
| 39 SdchPolicyDelegate::SdchPolicyDelegate(scoped_ptr<Context> context) |
| 40 : dictionary_requested_(false), |
| 41 context_(std::move(context)), |
| 42 did_meta_refresh_(false), |
| 43 did_stop_decoding_(false), |
| 44 did_fail_request_(false) {} |
| 45 |
| 46 SdchPolicyDelegate::~SdchPolicyDelegate() {} |
| 47 |
| 48 // Dictionary errors are often the first indication that the SDCH stream has |
| 49 // become corrupt. There are many possible causes: non-200 response codes, a |
| 50 // cached non-SDCH-ified reply, the server opting not to use SDCH, a cached |
| 51 // SDCH-ified reply for which the SdchManager did not have the dictionary, a |
| 52 // corrupted response, or a response that claims to be SDCH but isn't actually. |
| 53 // These are handled here by issuing a meta-refresh or swapping to passthrough |
| 54 // mode if appropriate, or failing the request if the error is unrecoverable. |
| 55 bool SdchPolicyDelegate::HandleDictionaryError(SdchStreamSource* source) { |
| 56 GURL url; |
| 57 if (!context_->GetURL(&url)) { |
| 58 did_fail_request_ = true; |
| 59 return false; |
| 60 } |
| 61 |
| 62 LogSdchDictionaryError(); |
| 63 |
| 64 // HTTP 404 might be an unencoded error page, so if decoding failed, pass it |
| 65 // through. TODO(516773) |
| 66 if (context_->GetResponseCode() == 404) { |
| 67 did_stop_decoding_ = true; |
| 68 source->StopDecoding(); |
| 69 return true; |
| 70 } |
| 71 |
| 72 // HTTP !200 gets a meta-refresh for HTML and a hard failure otherwise. |
| 73 if (context_->GetResponseCode() != 200) |
| 74 return IssueMetaRefreshIfPossible(source); |
| 75 |
| 76 // If this is a cached result and the source hasn't requested a dictionary, it |
| 77 // probably never had a dictionary to begin and is an unencoded response from |
| 78 // earlier. If the source has requested a dictionary, but there was still a |
| 79 // dictionary error, then the SdchManager does not have it so this method |
| 80 // needs to issue a meta-refresh to get it. |
| 81 if (context_->IsCachedContent() && !dictionary_requested_) { |
| 82 did_stop_decoding_ = true; |
| 83 source->StopDecoding(); |
| 84 return true; |
| 85 } |
| 86 |
| 87 // Ow. The original request didn't advertise any dictionaries, but the |
| 88 // response claimed to be SDCH, but did not have a plausible dictionary hash. |
| 89 // There is no way to repair this situation: the original request already |
| 90 // didn't advertise any dictionaries, and retrying it would likely have the |
| 91 // same result. Blacklist the domain and try passing through. |
| 92 if (!context_->SdchDictionariesAdvertised() && !dictionary_requested_) { |
| 93 did_stop_decoding_ = true; |
| 94 source->StopDecoding(); |
| 95 context_->GetSdchManager()->BlacklistDomain(url, |
| 96 SDCH_PASSING_THROUGH_NON_SDCH); |
| 97 return true; |
| 98 } |
| 99 |
| 100 return IssueMetaRefreshIfPossible(source); |
| 101 } |
| 102 |
| 103 // A decoding error, as opposed to a dictionary error, indicates a decompression |
| 104 // failure partway through the payload of the SDCH stream, which means that the |
| 105 // filter already witnessed a valid dictionary ID and successfully retrieved a |
| 106 // dictionary for it. Decoding errors are not recoverable and it is not |
| 107 // appropriate to stop decoding, so there are relatively few error cases here. |
| 108 // |
| 109 // In particular, a decoding error for an HTML payload is recoverable by issuing |
| 110 // a meta-refresh, but to avoid having that happen too often, this class also |
| 111 // temporarily blacklists the domain. A decoding error for a non-HTML payload is |
| 112 // unrecoverable, so such an error gets a permanent blacklist entry. If the |
| 113 // content was cached, no blacklisting is needed. |
| 114 bool SdchPolicyDelegate::HandleDecodingError(SdchStreamSource* source) { |
| 115 LogSdchDecodingError(); |
| 116 return IssueMetaRefreshIfPossible(source); |
| 117 } |
| 118 |
| 119 bool SdchPolicyDelegate::GetDictionary(const std::string& server_id, |
| 120 const std::string** text) { |
| 121 dictionary_requested_ = true; |
| 122 SdchManager::DictionarySet* set = context_->SdchDictionariesAdvertised(); |
| 123 if (set) { |
| 124 *text = set->GetDictionaryText(server_id); |
| 125 if (!(*text)->empty()) { |
| 126 LOG(ERROR) << "GetDictionary success!"; |
| 127 return true; |
| 128 } |
| 129 } |
| 130 GURL url; |
| 131 if (!context_->GetURL(&url)) |
| 132 return false; |
| 133 SdchProblemCode rv = SDCH_OK; |
| 134 unexpected_dictionary_set_ = |
| 135 context_->GetSdchManager()->GetDictionarySetByHash(url, server_id, &rv); |
| 136 if (unexpected_dictionary_set_) { |
| 137 *text = unexpected_dictionary_set_->GetDictionaryText(server_id); |
| 138 // XXX: log fallback here (UNADVERTISED_DICTIONARY_USED etc) |
| 139 if (!(*text)->empty()) |
| 140 return true; |
| 141 } |
| 142 // XXX: check for HASH_NOT_FOUND / HASH_MALFORMED here? or in |
| 143 // SdchStreamSource? |
| 144 return false; |
| 145 } |
| 146 |
| 147 void SdchPolicyDelegate::NotifyStreamDone() { |
| 148 // Don't understand what to do with these. |
| 149 #if 0 |
| 150 if (did_fail_request_) |
| 151 UMA_HISTOGRAM_COUNTS("Sdch4.StreamFate", STREAM_FATE_FAIL); |
| 152 else if (did_meta_refresh_) |
| 153 UMA_HISTOGRAM_COUNTS("Sdch4.StreamFate", STREAM_FATE_REFRESH); |
| 154 else if (did_stop_decoding_) |
| 155 UMA_HISTOGRAM_COUNTS("Sdch4.StreamFate", STREAM_FATE_STOP_DECODING); |
| 156 else |
| 157 UMA_HISTOGRAM_COUNTS("Sdch4.StreamFate", STREAM_FATE_OK); |
| 158 #endif |
| 159 } |
| 160 |
| 161 bool SdchPolicyDelegate::IssueMetaRefreshIfPossible(SdchStreamSource* source) { |
| 162 std::string mime_type; |
| 163 if (!context_->GetMimeType(&mime_type)) { |
| 164 did_fail_request_ = true; |
| 165 return false; |
| 166 } |
| 167 GURL url; |
| 168 if (!context_->GetURL(&url)) { |
| 169 did_fail_request_ = true; |
| 170 return false; |
| 171 } |
| 172 SdchManager* manager = context_->GetSdchManager(); |
| 173 |
| 174 // Errors for non-HTML payloads are unrecoverable and get the domain |
| 175 // blacklisted indefinitely. |
| 176 if (mime_type.npos == mime_type.find("text/html")) { |
| 177 SdchProblemCode problem = |
| 178 (context_->IsCachedContent() ? SDCH_CACHED_META_REFRESH_UNSUPPORTED |
| 179 : SDCH_META_REFRESH_UNSUPPORTED); |
| 180 manager->BlacklistDomainForever(url, problem); |
| 181 did_fail_request_ = true; |
| 182 return false; |
| 183 } |
| 184 |
| 185 if (!context_->IsCachedContent()) |
| 186 manager->BlacklistDomain(url, SDCH_META_REFRESH_RECOVERY); |
| 187 |
| 188 source->ReplaceOutput(kRefreshHtml, strlen(kRefreshHtml)); |
| 189 did_meta_refresh_ = true; |
| 190 return true; |
| 191 } |
| 192 |
| 193 // Old histograms: Sdch3. |
| 194 // FilterUseBeforeDisabling |
| 195 // PartialBytesIn, PartialVcdiffIn, PartialVcdiffOut |
| 196 // UnflushedBytesIn, UnflushedBufferSize, UnflushedVcdiffIn, |
| 197 // UnflushedVcdiffOut |
| 198 // Network_Decode_Ratio_a |
| 199 // Network_Decode_Bytes_VcdiffOut_a |
| 200 // NetworkBytesSavedByCompression |
| 201 // ResponseCorruptionDetection.{Cached,Uncached} |
| 202 |
| 203 // Decoding errors only produce Sdch3.ResponseCorruptionDetection histograms. To |
| 204 // have a decoding error, the dictionary header must have been valid, and the |
| 205 // dictionary must have been loaded successfully, but the response doesn't |
| 206 // decode successfully, so it is corrupt. |
| 207 void SdchPolicyDelegate::LogSdchDecodingError() { |
| 208 if (context_->IsCachedContent()) { |
| 209 UMA_HISTOGRAM_ENUMERATION("Sdch3.ResponseCorruptionDetection.Cached", |
| 210 STREAM_FATE_CAUSE_CORRUPT_SDCH, |
| 211 STREAM_FATE_CAUSE_MAX); |
| 212 } else { |
| 213 UMA_HISTOGRAM_ENUMERATION("Sdch3.ResponseCorruptionDetection.Uncached", |
| 214 STREAM_FATE_CAUSE_CORRUPT_SDCH, |
| 215 STREAM_FATE_CAUSE_MAX); |
| 216 } |
| 217 } |
| 218 |
| 219 void SdchPolicyDelegate::LogSdchDictionaryError() { |
| 220 std::string mime_type; |
| 221 if (!context_->GetMimeType(&mime_type)) |
| 222 return; |
| 223 // TODO(ellyjones): figure out what stats to gather here |
| 224 } |
| 225 |
| 226 } // namespace net |
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Chromium Code Reviews
Issue 1662763002:
[ON HOLD] Implement pull-based design for content decoding (Closed)
Base URL: https://chromium.googlesource.com/chromium/src.git@master