src/adaptation/icap/ModXact.h

   1 /*
   2  * Copyright (C) 1996-2020 The Squid Software Foundation and contributors
   3  *
   4  * Squid software is distributed under GPLv2+ license and includes
   5  * contributions from numerous individuals and organizations.
   6  * Please see the COPYING and CONTRIBUTORS files for details.
   7  */
   8
   9 #ifndef SQUID_ICAPMODXACT_H
  10 #define SQUID_ICAPMODXACT_H
  11
  12 #include "AccessLogEntry.h"
  13 #include "adaptation/icap/InOut.h"
  14 #include "adaptation/icap/Launcher.h"
  15 #include "adaptation/icap/Xaction.h"
  16 #include "BodyPipe.h"
  17 #include "http/one/forward.h"
  18 #include "http/one/TeChunkedParser.h"
  19
  20 /*
  21  * ICAPModXact implements ICAP REQMOD and RESPMOD transaction using
  22  * ICAPXaction as the base. The ICAPModXact receives a virgin HTTP message
  23  * from an ICAP vecoring point, (a.k.a., initiator), communicates with the
  24  * ICAP server, and sends the adapted HTTP message headers back.
  25  * Virgin/adapted HTTP message body is reveived/sent using BodyPipe
  26  * interface. The initiator (or its associate) is expected to send and/or
  27  * receive the HTTP body.
  28  */
  29
  30 namespace Adaptation
  31 {
  32 namespace Icap
  33 {
  34
  35 // estimated future presence and size of something (e.g., HTTP body)
  36
  37 class SizedEstimate
  38 {
  39
  40 public:
  41     SizedEstimate(); // not expected by default
  42     void expect(int64_t aSize); // expect with any, even unknown size
  43     bool expected() const;
  44
  45     /* other members can be accessed iff expected() */
  46
  47     bool knownSize() const;
  48     uint64_t size() const; // can be accessed iff knownSize()
  49
  50 private:
  51     enum { dtUnexpected = -2, dtUnknown = -1 };
  52     int64_t theData; // combines expectation and size info to save RAM
  53 };
  54
  55 // Virgin body may be used for two activities: (a) writing preview or prime
  56 // body to the ICAP server and (b) sending the body back in the echo mode.
  57 // Both activities use the same BodyPipe and may be active at the same time.
  58 // This class is used to maintain the state of body writing or sending
  59 // activity and to coordinate consumption of the shared virgin body buffer.
  60 class VirginBodyAct
  61 {
  62
  63 public:
  64     VirginBodyAct();
  65
  66     void plan(); // the activity may happen; do not consume at or above offset
  67     void disable(); // the activity will not continue; no consumption restrictions
  68
  69     bool active() const { return theState == stActive; }
  70     bool disabled() const { return theState == stDisabled; }
  71
  72     // methods below require active()
  73
  74     uint64_t offset() const; // the absolute beginning of not-yet-acted-on data
  75     void progress(size_t size); // note processed body bytes
  76
  77 private:
  78     int64_t theStart; // unprocessed virgin body data offset
  79
  80     typedef enum { stUndecided, stActive, stDisabled } State;
  81     State theState;
  82 };
  83
  84 // maintains preview-related sizes
  85
  86 class Preview
  87 {
  88
  89 public:
  90     Preview();            // disabled
  91     void enable(size_t anAd); // enabled with advertised size
  92     bool enabled() const;
  93
  94     /* other members can be accessed iff enabled() */
  95
  96     size_t ad() const;      // advertised preview size
  97     size_t debt() const;    // remains to write
  98     bool done() const;      // wrote everything
  99     bool ieof() const;      // premature EOF
 100
 101     void wrote(size_t size, bool wroteEof);
 102
 103 private:
 104     size_t theWritten;
 105     size_t theAd;
 106     enum State { stDisabled, stWriting, stIeof, stDone } theState;
 107 };
 108
 109 /// Parses and stores ICAP trailer header block.
 110 class TrailerParser
 111 {
 112 public:
 113     TrailerParser() : trailer(hoReply), hdr_sz(0) {}
 114     /// Parses trailers stored in a buffer.
 115     /// \returns true and sets hdr_sz on success
 116     /// \returns false and sets *error to zero when needs more data
 117     /// \returns false and sets *error to a positive Http::StatusCode on error
 118     bool parse(const char *buf, int len, int atEnd, Http::StatusCode *error);
 119     HttpHeader trailer;
 120     /// parsed trailer size if parse() was successful
 121     size_t hdr_sz; // pedantic XXX: wrong type dictated by HttpHeader::parse() API
 122 };
 123
 124 /// handles ICAP-specific chunk extensions supported by Squid
 125 class ChunkExtensionValueParser: public Http1::ChunkExtensionValueParser
 126 {
 127 public:
 128     /* Http1::ChunkExtensionValueParser API */
 129     virtual void parse(Tokenizer &tok, const SBuf &extName) override;
 130
 131     bool sawUseOriginalBody() const { return useOriginalBody_ >= 0; }
 132     uint64_t useOriginalBody() const { assert(sawUseOriginalBody()); return static_cast<uint64_t>(useOriginalBody_); }
 133
 134 private:
 135     static const SBuf UseOriginalBodyName;
 136
 137     /// the value of the parsed use-original-body chunk extension (or -1)
 138     int64_t useOriginalBody_ = -1;
 139 };
 140
 141 class ModXact: public Xaction, public BodyProducer, public BodyConsumer
 142 {
 143     CBDATA_CLASS(ModXact);
 144
 145 public:
 146     ModXact(Http::Message *virginHeader, HttpRequest *virginCause, AccessLogEntry::Pointer &alp, ServiceRep::Pointer &s);
 147     virtual ~ModXact();
 148
 149     // BodyProducer methods
 150     virtual void noteMoreBodySpaceAvailable(BodyPipe::Pointer);
 151     virtual void noteBodyConsumerAborted(BodyPipe::Pointer);
 152
 153     // BodyConsumer methods
 154     virtual void noteMoreBodyDataAvailable(BodyPipe::Pointer);
 155     virtual void noteBodyProductionEnded(BodyPipe::Pointer);
 156     virtual void noteBodyProducerAborted(BodyPipe::Pointer);
 157
 158     // comm handlers
 159     virtual void handleCommConnected();
 160     virtual void handleCommWrote(size_t size);
 161     virtual void handleCommRead(size_t size);
 162     void handleCommWroteHeaders();
 163     void handleCommWroteBody();
 164
 165     // service waiting
 166     void noteServiceReady();
 167     void noteServiceAvailable();
 168
 169 public:
 170     InOut virgin;
 171     InOut adapted;
 172
 173     // bypasses exceptions if needed and possible
 174     virtual void callException(const std::exception &e);
 175
 176     /// record error detail in the virgin request if possible
 177     virtual void detailError(int errDetail);
 178     // Icap::Xaction API
 179     virtual void clearError();
 180     /// The master transaction log entry
 181     virtual AccessLogEntry::Pointer masterLogEntry() { return alMaster; }
 182
 183 private:
 184     virtual void start();
 185
 186     /// locates the request, either as a cause or as a virgin message itself
 187     const HttpRequest &virginRequest() const; // Must always be available
 188
 189     void estimateVirginBody();
 190     void makeAdaptedBodyPipe(const char *what);
 191
 192     void waitForService();
 193
 194     // will not send anything [else] on the adapted pipe
 195     bool doneSending() const;
 196
 197     void startWriting();
 198     void writeMore();
 199     void writePreviewBody();
 200     void writePrimeBody();
 201     void writeSomeBody(const char *label, size_t size);
 202     void decideWritingAfterPreview(const char *previewKind);
 203
 204     void startReading();
 205     void readMore();
 206     virtual bool doneReading() const { return commEof || state.doneParsing(); }
 207     virtual bool doneWriting() const { return state.doneWriting(); }
 208
 209     size_t virginContentSize(const VirginBodyAct &act) const;
 210     const char *virginContentData(const VirginBodyAct &act) const;
 211     bool virginBodyEndReached(const VirginBodyAct &act) const;
 212
 213     void makeRequestHeaders(MemBuf &buf);
 214     void makeAllowHeader(MemBuf &buf);
 215     void makeUsernameHeader(const HttpRequest *request, MemBuf &buf);
 216     void addLastRequestChunk(MemBuf &buf);
 217     void openChunk(MemBuf &buf, size_t chunkSize, bool ieof);
 218     void closeChunk(MemBuf &buf);
 219     void virginConsume();
 220     void finishNullOrEmptyBodyPreview(MemBuf &buf);
 221
 222     void decideOnPreview();
 223     void decideOnRetries();
 224     bool shouldAllow204();
 225     bool shouldAllow206any();
 226     bool shouldAllow206in();
 227     bool shouldAllow206out();
 228     bool canBackupEverything() const;
 229
 230     void prepBackup(size_t expectedSize);
 231     void backup(const MemBuf &buf);
 232
 233     void parseMore();
 234
 235     void parseHeaders();
 236     void parseIcapHead();
 237     void parseHttpHead();
 238     bool parseHead(Http::Message *head);
 239
 240     void decideOnParsingBody();
 241     void parseBody();
 242     void parseIcapTrailer();
 243     void maybeAllocateHttpMsg();
 244
 245     void handle100Continue();
 246     bool validate200Ok();
 247     void handle200Ok();
 248     void handle204NoContent();
 249     void handle206PartialContent();
 250     void handleUnknownScode();
 251
 252     void bypassFailure();
 253
 254     void startSending();
 255     void disableBypass(const char *reason, bool includeGroupBypass);
 256
 257     void prepEchoing();
 258     void prepPartialBodyEchoing(uint64_t pos);
 259     void echoMore();
 260     void updateSources(); ///< Update the Http::Message sources
 261
 262     virtual bool doneAll() const;
 263     virtual void swanSong();
 264
 265     void stopReceiving();
 266     void stopSending(bool nicely);
 267     void stopWriting(bool nicely);
 268     void stopParsing(const bool checkUnparsedData = true);
 269     void stopBackup();
 270
 271     virtual void fillPendingStatus(MemBuf &buf) const;
 272     virtual void fillDoneStatus(MemBuf &buf) const;
 273     virtual bool fillVirginHttpHeader(MemBuf&) const;
 274
 275 private:
 276     /// parses a message header or trailer
 277     /// \returns true on success
 278     /// \returns false if more data is needed
 279     /// \throw TextException on unrecoverable error
 280     template<class Part>
 281     bool parsePart(Part *part, const char *description);
 282
 283     void packHead(MemBuf &httpBuf, const Http::Message *head);
 284     void encapsulateHead(MemBuf &icapBuf, const char *section, MemBuf &httpBuf, const Http::Message *head);
 285     bool gotEncapsulated(const char *section) const;
 286     /// whether ICAP response header indicates HTTP header presence
 287     bool expectHttpHeader() const;
 288     /// whether ICAP response header indicates HTTP body presence
 289     bool expectHttpBody() const;
 290     /// whether ICAP response header indicates ICAP trailers presence
 291     bool expectIcapTrailers() const;
 292     void checkConsuming();
 293
 294     virtual void finalizeLogInfo();
 295
 296     SizedEstimate virginBody;
 297     VirginBodyAct virginBodyWriting; // virgin body writing state
 298     VirginBodyAct virginBodySending;  // virgin body sending state
 299     uint64_t virginConsumed;        // virgin data consumed so far
 300     Preview preview; // use for creating (writing) the preview
 301
 302     Http1::TeChunkedParser *bodyParser; // ICAP response body parser
 303
 304     bool canStartBypass; // enables bypass of transaction failures
 305     bool protectGroupBypass; // protects ServiceGroup-wide bypass of failures
 306
 307     /**
 308      * size of HTTP header in ICAP reply or -1 if there is not any encapsulated
 309      * message data
 310      */
 311     int64_t replyHttpHeaderSize;
 312     /**
 313      * size of dechunked HTTP body in ICAP reply or -1 if there is not any
 314      * encapsulated message data
 315      */
 316     int64_t replyHttpBodySize;
 317
 318     int adaptHistoryId; ///< adaptation history slot reservation
 319
 320     TrailerParser *trailerParser;
 321
 322     ChunkExtensionValueParser extensionParser;
 323
 324     class State
 325     {
 326
 327     public:
 328         State();
 329
 330     public:
 331
 332         bool serviceWaiting; // waiting for ICAP service options
 333         bool allowedPostview204; // mmust handle 204 No Content outside preview
 334         bool allowedPostview206; // must handle 206 Partial Content outside preview
 335         bool allowedPreview206; // must handle 206 Partial Content inside preview
 336         bool readyForUob; ///< got a 206 response and expect a use-origin-body
 337         bool waitedForService; ///< true if was queued at least once
 338
 339         // will not write anything [else] to the ICAP server connection
 340         bool doneWriting() const { return writing == writingReallyDone; }
 341
 342         // will not use virgin.body_pipe
 343         bool doneConsumingVirgin() const {
 344             return writing >= writingAlmostDone
 345                    && ((sending == sendingAdapted && !readyForUob) ||
 346                        sending == sendingDone);
 347         }
 348
 349         // parsed entire ICAP response from the ICAP server
 350         bool doneParsing() const { return parsing == psDone; }
 351
 352         // is parsing ICAP or HTTP headers read from the ICAP server
 353         bool parsingHeaders() const {
 354             return parsing == psIcapHeader ||
 355                    parsing == psHttpHeader;
 356         }
 357
 358         enum Parsing { psIcapHeader, psHttpHeader, psBody, psIcapTrailer, psDone } parsing;
 359
 360         // measures ICAP request writing progress
 361         enum Writing { writingInit, writingConnect, writingHeaders,
 362                        writingPreview, writingPaused, writingPrime,
 363                        writingAlmostDone, // waiting for the last write() call to finish
 364                        writingReallyDone
 365                      } writing;
 366
 367         enum Sending { sendingUndecided, sendingVirgin, sendingAdapted,
 368                        sendingDone
 369                      } sending;
 370     } state;
 371
 372     AccessLogEntry::Pointer alMaster; ///< Master transaction AccessLogEntry
 373 };
 374
 375 // An Launcher that stores ModXact construction info and
 376 // creates ModXact when needed
 377 class ModXactLauncher: public Launcher
 378 {
 379     CBDATA_CLASS(ModXactLauncher);
 380
 381 public:
 382     ModXactLauncher(Http::Message *virginHeader, HttpRequest *virginCause, AccessLogEntry::Pointer &alp, Adaptation::ServicePointer s);
 383
 384 protected:
 385     virtual Xaction *createXaction();
 386
 387     virtual void swanSong();
 388
 389     /// starts or stops transaction accounting in ICAP history
 390     void updateHistory(bool start);
 391
 392     InOut virgin;
 393
 394     AccessLogEntry::Pointer al;
 395 };
 396
 397 } // namespace Icap
 398 } // namespace Adaptation
 399
 400 #endif /* SQUID_ICAPMOD_XACT_H */
 401