src/refresh.cc

   1 /*
   2  * Copyright (C) 1996-2015 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 /* DEBUG: section 22    Refresh Calculation */
  10
  11 #ifndef USE_POSIX_REGEX
  12 #define USE_POSIX_REGEX     /* put before includes; always use POSIX */
  13 #endif
  14
  15 #include "squid.h"
  16 #include "HttpHdrCc.h"
  17 #include "HttpReply.h"
  18 #include "HttpRequest.h"
  19 #include "MemObject.h"
  20 #include "mgr/Registration.h"
  21 #include "RefreshPattern.h"
  22 #include "SquidConfig.h"
  23 #include "SquidTime.h"
  24 #include "Store.h"
  25 #include "URL.h"
  26 #include "util.h"
  27
  28 typedef enum {
  29     rcHTTP,
  30     rcICP,
  31 #if USE_HTCP
  32     rcHTCP,
  33 #endif
  34 #if USE_CACHE_DIGESTS
  35     rcCDigest,
  36 #endif
  37     rcStore,
  38     rcCount
  39 } refreshCountsEnum;
  40
  41 /**
  42  * Flags indicating which staleness algorithm has been applied.
  43  */
  44 typedef struct {
  45     bool expires;  ///< Expires: header absolute timestamp limit
  46     bool min;      ///< Heuristic minimum age limited
  47     bool lmfactor; ///< Last-Modified with heuristic determines limit
  48     bool max;      ///< Configured maximum age limit
  49 } stale_flags;
  50
  51 /*
  52  * This enumerated list assigns specific values, ala HTTP/FTP status
  53  * codes.  All Fresh codes are in the range 100-199 and all stale
  54  * codes are 200-299.  We might want to use these codes in logging,
  55  * so best to keep them consistent over time.
  56  */
  57 enum {
  58     FRESH_REQUEST_MAX_STALE_ALL = 100,
  59     FRESH_REQUEST_MAX_STALE_VALUE,
  60     FRESH_EXPIRES,
  61     FRESH_LMFACTOR_RULE,
  62     FRESH_MIN_RULE,
  63     FRESH_OVERRIDE_EXPIRES,
  64     FRESH_OVERRIDE_LASTMOD,
  65     STALE_MUST_REVALIDATE = 200,
  66     STALE_RELOAD_INTO_IMS,
  67     STALE_FORCED_RELOAD,
  68     STALE_EXCEEDS_REQUEST_MAX_AGE_VALUE,
  69     STALE_EXPIRES,
  70     STALE_MAX_RULE,
  71     STALE_LMFACTOR_RULE,
  72     STALE_MAX_STALE,
  73     STALE_DEFAULT = 299
  74 };
  75
  76 static struct RefreshCounts {
  77     const char *proto;
  78     int total;
  79     int status[STALE_DEFAULT + 1];
  80 } refreshCounts[rcCount];
  81
  82 static const RefreshPattern *refreshUncompiledPattern(const char *);
  83 static OBJH refreshStats;
  84 static int refreshStaleness(const StoreEntry * entry, time_t check_time, const time_t age, const RefreshPattern * R, stale_flags * sf);
  85
  86 static RefreshPattern DefaultRefresh("<none>", 0);
  87
  88 /** Locate the first refresh_pattern rule that matches the given URL by regex.
  89  *
  90  * \return A pointer to the refresh_pattern parameters to use, or nullptr if there is no match.
  91  */
  92 const RefreshPattern *
  93 refreshLimits(const char *url)
  94 {
  95     for (auto R = Config.Refresh; R; R = R->next) {
  96         ++(R->stats.matchTests);
  97         if (R->pattern.match(url)) {
  98             ++(R->stats.matchCount);
  99             return R;
 100         }
 101     }
 102
 103     return nullptr;
 104 }
 105
 106 /** Locate the first refresh_pattern rule that has the given uncompiled regex.
 107  *
 108  * \note There is only one reference to this function, below. It always passes "." as the pattern.
 109  * This function is only ever called if there is no URI. Because a regex match is impossible, Squid
 110  * forces the "." rule to apply (if it exists)
 111  *
 112  * \return A pointer to the refresh_pattern parameters to use, or nullptr if there is no match.
 113  */
 114 static const RefreshPattern *
 115 refreshUncompiledPattern(const char *pat)
 116 {
 117     for (auto R = Config.Refresh; R; R = R->next) {
 118         if (0 == strcmp(R->pattern.c_str(), pat))
 119             return R;
 120     }
 121
 122     return nullptr;
 123 }
 124
 125 /**
 126  * Calculate how stale the response is (or will be at the check_time).
 127  *
 128  * We try the following ways until one gives a result:
 129  *
 130  * 1. response expiration time, if one was set
 131  * 2. age greater than configured maximum
 132  * 3. last-modified factor algorithm
 133  * 4. age less than configured minimum
 134  * 5. default (stale)
 135  *
 136  * \param entry       the StoreEntry being examined
 137  * \param check_time  the time (maybe future) at which we want to know whether $
 138  * \param age         the age of the entry at check_time
 139  * \param R           the refresh_pattern rule that matched this entry
 140  * \param sf          small struct to indicate reason for stale/fresh decision
 141  *
 142  * \retval -1  If the response is fresh.
 143  * \retval >0  The amount of staleness.
 144  * \retval 0   NOTE return value of 0 means the response is stale.
 145  */
 146 static int
 147 refreshStaleness(const StoreEntry * entry, time_t check_time, const time_t age, const RefreshPattern * R, stale_flags * sf)
 148 {
 149     // 1. If the cached object has an explicit expiration time, then we rely on this and
 150     //    completely ignore the Min, Percent and Max values in the refresh_pattern.
 151     if (entry->expires > -1) {
 152         sf->expires = true;
 153
 154         if (entry->expires > check_time) {
 155             debugs(22, 3, "FRESH: expires " << entry->expires <<
 156                    " >= check_time " << check_time << " ");
 157
 158             return -1;
 159         } else {
 160             debugs(22, 3, "STALE: expires " << entry->expires <<
 161                    " < check_time " << check_time << " ");
 162
 163             return (check_time - entry->expires);
 164         }
 165     }
 166
 167     debugs(22, 3, "No explicit expiry given, using heuristics to determine freshness");
 168
 169     // 2. If the entry is older than the maximum age in the refresh_pattern, it is STALE.
 170     if (age > R->max) {
 171         debugs(22, 3, "STALE: age " << age << " > max " << R->max << " ");
 172         sf->max = true;
 173         return (age - R->max);
 174     }
 175
 176     // 3. If there is a Last-Modified header, try the last-modified factor algorithm.
 177     if (entry->lastmod > -1 && entry->timestamp > entry->lastmod) {
 178
 179         /* lastmod_delta is the difference between the last-modified date of the response
 180          * and the time we cached it. It's how "old" the response was when we got it.
 181          */
 182         time_t lastmod_delta = entry->timestamp - entry->lastmod;
 183
 184         /* stale_age is the age of the response when it became/becomes stale according to
 185          * the last-modified factor algorithm. It's how long we can consider the response
 186          * fresh from the time we cached it.
 187          */
 188         time_t stale_age = static_cast<time_t>(lastmod_delta * R->pct);
 189
 190         debugs(22,3, "Last modified " << lastmod_delta << " sec before we cached it, L-M factor " <<
 191                (100.0 * R->pct) << "% = " << stale_age << " sec freshness lifetime");
 192         sf->lmfactor = true;
 193
 194         if (age >= stale_age) {
 195             debugs(22, 3, "STALE: age " << age << " > stale_age " << stale_age);
 196             return (age - stale_age);
 197         } else {
 198             debugs(22, 3, "FRESH: age " << age << " <= stale_age " << stale_age);
 199             return -1;
 200         }
 201     }
 202
 203     // 4. If the entry is not as old as the minimum age in the refresh_pattern, it is FRESH.
 204     if (age < R->min) {
 205         debugs(22, 3, "FRESH: age (" << age << " sec) is less than configured minimum (" << R->min << " sec)");
 206         sf->min = true;
 207         return -1;
 208     }
 209
 210     // 5. default is stale, by the amount we missed the minimum by
 211     debugs(22, 3, "STALE: No explicit expiry, no last modified, and older than configured minimum.");
 212     return (age - R->min);
 213 }
 214
 215 /** Checks whether a store entry is fresh or stale, and why.
 216  *
 217  * This is where all aspects of request, response and squid configuration
 218  * meet to decide whether a response is cacheable or not:
 219  *
 220  * 1. Client request headers that affect cacheability, e.g.
 221  *  - Cache-Control: no-cache
 222  *  - Cache-Control: max-age=N
 223  *  - Cache-Control: max-stale[=N]
 224  *  - Pragma: no-cache
 225  *
 226  * 2. Server response headers that affect cacheability, e.g.
 227  *  - Age:
 228  *  - Cache-Control: proxy-revalidate
 229  *  - Cache-Control: must-revalidate
 230  *  - Cache-Control: no-cache
 231  *  - Cache-Control: max-age=N
 232  *  - Cache-Control: s-maxage=N
 233  *  - Date:
 234  *  - Expires:
 235  *  - Last-Modified:
 236  *
 237  * 3. Configuration options, e.g.
 238  *  - reload-into-ims (refresh_pattern)
 239  *  - ignore-reload (refresh_pattern)
 240  *  - refresh-ims (refresh_pattern)
 241  *  - override-lastmod (refresh_pattern)
 242  *  - override-expire (refresh_pattern)
 243  *  - reload_into_ims (global option)
 244  *  - refresh_all_ims (global option)
 245  *
 246  * \returns a status code (from enum above):
 247  *  - FRESH_REQUEST_MAX_STALE_ALL
 248  *  - FRESH_REQUEST_MAX_STALE_VALUE
 249  *  - FRESH_EXPIRES
 250  *  - FRESH_LMFACTOR_RULE
 251  *  - FRESH_MIN_RULE
 252  *  - FRESH_OVERRIDE_EXPIRES
 253  *  - FRESH_OVERRIDE_LASTMOD
 254  *  - STALE_MUST_REVALIDATE
 255  *  - STALE_RELOAD_INTO_IMS
 256  *  - STALE_FORCED_RELOAD
 257  *  - STALE_EXCEEDS_REQUEST_MAX_AGE_VALUE
 258  *  - STALE_EXPIRES
 259  *  - STALE_MAX_RULE
 260  *  - STALE_LMFACTOR_RULE
 261  *  - STALE_MAX_STALE
 262  *  - STALE_DEFAULT
 263  *
 264  * \note request may be NULL (e.g. for cache digests build)
 265  *
 266  * \note the store entry being examined is not necessarily cached (e.g. if
 267  *       this response is being evaluated for the first time)
 268  */
 269 static int
 270 refreshCheck(const StoreEntry * entry, HttpRequest * request, time_t delta)
 271 {
 272     time_t age = 0;
 273     time_t check_time = squid_curtime + delta;
 274     int staleness;
 275     stale_flags sf;
 276
 277     // get the URL of this entry, if there is one
 278     static const SBuf nilUri("<none>");
 279     SBuf uri = nilUri;
 280     if (entry->mem_obj)
 281         uri = entry->mem_obj->storeId();
 282     else if (request)
 283         uri = request->effectiveRequestUri();
 284
 285     debugs(22, 3, "checking freshness of URI: " << uri);
 286
 287     // age is not necessarily the age now, but the age at the given check_time
 288     if (check_time > entry->timestamp)
 289         age = check_time - entry->timestamp;
 290
 291     // FIXME: what to do when age < 0 or counter overflow?
 292     assert(age >= 0);
 293
 294     /* We need a refresh rule. In order of preference:
 295      *
 296      *   1. the rule that matches this URI by regex
 297      *   2. the "." rule from the config file
 298      *   3. the default "." rule
 299      */
 300     // XXX: performance regression. c_str() reallocates
 301     const RefreshPattern *R = (uri != nilUri) ? refreshLimits(uri.c_str()) : refreshUncompiledPattern(".");
 302     if (NULL == R)
 303         R = &DefaultRefresh;
 304
 305     debugs(22, 3, "Matched '" << R->pattern.c_str() << " " <<
 306            (int) R->min << " " << (int) (100.0 * R->pct) << "%% " <<
 307            (int) R->max << "'");
 308
 309     debugs(22, 3, "\tage:\t" << age);
 310
 311     debugs(22, 3, "\tcheck_time:\t" << mkrfc1123(check_time));
 312
 313     debugs(22, 3, "\tentry->timestamp:\t" << mkrfc1123(entry->timestamp));
 314
 315     if (request && !request->flags.ignoreCc) {
 316         const HttpHdrCc *const cc = request->cache_control;
 317         if (cc && cc->hasMinFresh()) {
 318             const int32_t minFresh=cc->minFresh();
 319             debugs(22, 3, "\tage + min-fresh:\t" << age << " + " <<
 320                    minFresh << " = " << age + minFresh);
 321             debugs(22, 3, "\tcheck_time + min-fresh:\t" << check_time << " + "
 322                    << minFresh << " = " <<
 323                    mkrfc1123(check_time + minFresh));
 324             age += minFresh;
 325             check_time += minFresh;
 326         }
 327     }
 328
 329     memset(&sf, '\0', sizeof(sf));
 330
 331     staleness = refreshStaleness(entry, check_time, age, R, &sf);
 332
 333     debugs(22, 3, "Staleness = " << staleness);
 334
 335     // stale-if-error requires any failure be passed thru when its period is over.
 336     if (request && entry->mem_obj && entry->mem_obj->getReply() && entry->mem_obj->getReply()->cache_control &&
 337             entry->mem_obj->getReply()->cache_control->hasStaleIfError() &&
 338             entry->mem_obj->getReply()->cache_control->staleIfError() < staleness) {
 339
 340         debugs(22, 3, "stale-if-error period expired. Will produce error if validation fails.");
 341         request->flags.failOnValidationError = true;
 342     }
 343
 344     /* If the origin server specified either of:
 345      *   Cache-Control: must-revalidate
 346      *   Cache-Control: proxy-revalidate
 347      * the spec says the response must always be revalidated if stale.
 348      */
 349     if (EBIT_TEST(entry->flags, ENTRY_REVALIDATE) && staleness > -1) {
 350         debugs(22, 3, "YES: Must revalidate stale object (origin set must-revalidate, proxy-revalidate, no-cache, s-maxage, or private)");
 351         if (request)
 352             request->flags.failOnValidationError = true;
 353         return STALE_MUST_REVALIDATE;
 354     }
 355
 356     /* request-specific checks */
 357     if (request && !request->flags.ignoreCc) {
 358         HttpHdrCc *cc = request->cache_control;
 359
 360         /* If the request is an IMS request, and squid is configured NOT to service this from cache
 361          * (either by 'refresh-ims' in the refresh pattern or 'refresh_all_ims on' globally)
 362          * then force a reload from the origin.
 363          */
 364         if (request->flags.ims && (R->flags.refresh_ims || Config.onoff.refresh_all_ims)) {
 365             // The client's no-cache header is changed into a IMS query
 366             debugs(22, 3, "YES: Client IMS request forcing revalidation of object (refresh-ims option)");
 367             return STALE_FORCED_RELOAD;
 368         }
 369
 370 #if USE_HTTP_VIOLATIONS
 371         /* Normally a client reload request ("Cache-Control: no-cache" or "Pragma: no-cache")
 372          * means we must treat this reponse as STALE and fetch a new one.
 373          *
 374          * However, some options exist to override this behaviour. For example, we might just
 375          * revalidate our existing response, or even just serve it up without revalidating it.
 376          *
 377          *     ---- Note on the meaning of nocache_hack -----
 378          *
 379          * The nocache_hack flag has a very specific and complex meaning:
 380          *
 381          * (a) this is a reload request ("Cache-Control: no-cache" or "Pragma: no-cache" header)
 382          * and (b) the configuration file either has at least one refresh_pattern with
 383          * ignore-reload or reload-into-ims (not necessarily the rule matching this request) or
 384          * the global reload_into_ims is set to on
 385          *
 386          * In other words: this is a client reload, and we might need to override
 387          * the default behaviour (but we might not).
 388          *
 389          * "nocache_hack" is a pretty deceptive name for such a complicated meaning.
 390          */
 391         if (request->flags.noCacheHack()) {
 392
 393             if (R->flags.ignore_reload) {
 394                 /* The client's no-cache header is ignored completely - we'll try to serve
 395                  * what we have (assuming it's still fresh, etc.)
 396                  */
 397                 debugs(22, 3, "MAYBE: Ignoring client reload request - trying to serve from cache (ignore-reload option)");
 398             } else if (R->flags.reload_into_ims || Config.onoff.reload_into_ims) {
 399                 /* The client's no-cache header is not honoured completely - we'll just try
 400                  * to revalidate our cached copy (IMS to origin) instead of fetching a new
 401                  * copy with an unconditional GET.
 402                  */
 403                 debugs(22, 3, "YES: Client reload request - cheating, only revalidating with origin (reload-into-ims option)");
 404                 return STALE_RELOAD_INTO_IMS;
 405             } else {
 406                 /* The client's no-cache header is honoured - we fetch a new copy from origin */
 407                 debugs(22, 3, "YES: Client reload request - fetching new copy from origin");
 408                 request->flags.noCache = true;
 409                 return STALE_FORCED_RELOAD;
 410             }
 411         }
 412 #endif
 413
 414         // Check the Cache-Control client request header
 415         if (NULL != cc) {
 416
 417             // max-age directive
 418             if (cc->hasMaxAge()) {
 419 #if USE_HTTP_VIOLATIONS
 420                 // Ignore client "Cache-Control: max-age=0" header
 421                 if (R->flags.ignore_reload && cc->maxAge() == 0) {
 422                     debugs(22, 3, "MAYBE: Ignoring client reload request - trying to serve from cache (ignore-reload option)");
 423                 } else
 424 #endif
 425                 {
 426                     // Honour client "Cache-Control: max-age=x" header
 427                     if (age > cc->maxAge() || cc->maxAge() == 0) {
 428                         debugs(22, 3, "YES: Revalidating object - client 'Cache-Control: max-age=" << cc->maxAge() << "'");
 429                         return STALE_EXCEEDS_REQUEST_MAX_AGE_VALUE;
 430                     }
 431                 }
 432             }
 433
 434             // max-stale directive
 435             if (cc->hasMaxStale() && staleness > -1) {
 436                 if (cc->maxStale()==HttpHdrCc::MAX_STALE_ANY) {
 437                     debugs(22, 3, "NO: Client accepts a stale response of any age - 'Cache-Control: max-stale'");
 438                     return FRESH_REQUEST_MAX_STALE_ALL;
 439                 } else if (staleness < cc->maxStale()) {
 440                     debugs(22, 3, "NO: Client accepts a stale response - 'Cache-Control: max-stale=" << cc->maxStale() << "'");
 441                     return FRESH_REQUEST_MAX_STALE_VALUE;
 442                 }
 443             }
 444         }
 445     }
 446
 447     // If the object is fresh, return the right FRESH_ code
 448     if (-1 == staleness) {
 449         debugs(22, 3, "Object isn't stale..");
 450         if (sf.expires) {
 451             debugs(22, 3, "returning FRESH_EXPIRES");
 452             return FRESH_EXPIRES;
 453         }
 454
 455         assert(!sf.max);
 456
 457         if (sf.lmfactor) {
 458             debugs(22, 3, "returning FRESH_LMFACTOR_RULE");
 459             return FRESH_LMFACTOR_RULE;
 460         }
 461
 462         assert(sf.min);
 463
 464         debugs(22, 3, "returning FRESH_MIN_RULE");
 465         return FRESH_MIN_RULE;
 466     }
 467
 468     /*
 469      * At this point the response is stale, unless one of
 470      * the override options kicks in.
 471      * NOTE: max-stale config blocks the overrides.
 472      */
 473     int max_stale = (R->max_stale >= 0 ? R->max_stale : Config.maxStale);
 474     if ( max_stale >= 0 && staleness > max_stale) {
 475         debugs(22, 3, "YES: refresh_pattern max-stale=N limit from squid.conf");
 476         if (request)
 477             request->flags.failOnValidationError = true;
 478         return STALE_MAX_STALE;
 479     }
 480
 481     if (sf.expires) {
 482 #if USE_HTTP_VIOLATIONS
 483
 484         if (R->flags.override_expire && age < R->min) {
 485             debugs(22, 3, "NO: Serving from cache - even though explicit expiry has passed, we enforce Min value (override-expire option)");
 486             return FRESH_OVERRIDE_EXPIRES;
 487         }
 488
 489 #endif
 490         return STALE_EXPIRES;
 491     }
 492
 493     if (sf.max)
 494         return STALE_MAX_RULE;
 495
 496     if (sf.lmfactor) {
 497 #if USE_HTTP_VIOLATIONS
 498         if (R->flags.override_lastmod && age < R->min) {
 499             debugs(22, 3, "NO: Serving from cache - even though L-M factor says the object is stale, we enforce Min value (override-lastmod option)");
 500             return FRESH_OVERRIDE_LASTMOD;
 501         }
 502 #endif
 503         debugs(22, 3, "YES: L-M factor says the object is stale'");
 504         return STALE_LMFACTOR_RULE;
 505     }
 506
 507     debugs(22, 3, "returning STALE_DEFAULT");
 508     return STALE_DEFAULT;
 509 }
 510
 511 /**
 512  * This is called by http.cc once it has received and parsed the origin server's
 513  * response headers. It uses the result as part of its algorithm to decide whether a
 514  * response should be cached.
 515  *
 516  * \retval true if the entry is cacheable, regardless of whether FRESH or STALE
 517  * \retval false if the entry is not cacheable
 518  *
 519  * TODO: this algorithm seems a bit odd and might not be quite right. Verify against HTTPbis.
 520  */
 521 bool
 522 refreshIsCachable(const StoreEntry * entry)
 523 {
 524     /*
 525      * Don't look at the request to avoid no-cache and other nuisances.
 526      * the object should have a mem_obj so the URL will be found there.
 527      * minimum_expiry_time seconds delta (defaults to 60 seconds), to
 528      * avoid objects which expire almost immediately, and which can't
 529      * be refreshed.
 530      */
 531     int reason = refreshCheck(entry, NULL, Config.minimum_expiry_time);
 532     ++ refreshCounts[rcStore].total;
 533     ++ refreshCounts[rcStore].status[reason];
 534
 535     if (reason < STALE_MUST_REVALIDATE)
 536         /* Does not need refresh. This is certainly cachable */
 537         return true;
 538
 539     if (entry->lastmod < 0)
 540         /* Last modified is needed to do a refresh */
 541         return false;
 542
 543     if (entry->mem_obj == NULL)
 544         /* no mem_obj? */
 545         return true;
 546
 547     if (entry->getReply() == NULL)
 548         /* no reply? */
 549         return true;
 550
 551     if (entry->getReply()->content_length == 0)
 552         /* No use refreshing (caching?) 0 byte objects */
 553         return false;
 554
 555     /* This seems to be refreshable. Cache it */
 556     return true;
 557 }
 558
 559 /// whether reply is stale if it is a hit
 560 static bool
 561 refreshIsStaleIfHit(const int reason)
 562 {
 563     switch (reason) {
 564     case FRESH_MIN_RULE:
 565     case FRESH_LMFACTOR_RULE:
 566     case FRESH_EXPIRES:
 567         return false;
 568     default:
 569         return true;
 570     }
 571 }
 572
 573 /**
 574  * Protocol-specific wrapper around refreshCheck() function.
 575  *
 576  * Note the reason for STALE/FRESH then return true/false respectively.
 577  *
 578  * \retval 1 if STALE
 579  * \retval 0 if FRESH
 580  */
 581 int
 582 refreshCheckHTTP(const StoreEntry * entry, HttpRequest * request)
 583 {
 584     int reason = refreshCheck(entry, request, 0);
 585     ++ refreshCounts[rcHTTP].total;
 586     ++ refreshCounts[rcHTTP].status[reason];
 587     request->flags.staleIfHit = refreshIsStaleIfHit(reason);
 588     return (Config.onoff.offline || reason < 200) ? 0 : 1;
 589 }
 590
 591 /// \see int refreshCheckHTTP(const StoreEntry * entry, HttpRequest * request)
 592 int
 593 refreshCheckICP(const StoreEntry * entry, HttpRequest * request)
 594 {
 595     int reason = refreshCheck(entry, request, 30);
 596     ++ refreshCounts[rcICP].total;
 597     ++ refreshCounts[rcICP].status[reason];
 598     return (reason < 200) ? 0 : 1;
 599 }
 600
 601 #if USE_HTCP
 602 /// \see int refreshCheckHTTP(const StoreEntry * entry, HttpRequest * request)
 603 int
 604 refreshCheckHTCP(const StoreEntry * entry, HttpRequest * request)
 605 {
 606     int reason = refreshCheck(entry, request, 10);
 607     ++ refreshCounts[rcHTCP].total;
 608     ++ refreshCounts[rcHTCP].status[reason];
 609     return (reason < 200) ? 0 : 1;
 610 }
 611
 612 #endif
 613
 614 #if USE_CACHE_DIGESTS
 615 /// \see int refreshCheckHTTP(const StoreEntry * entry, HttpRequest * request)
 616 int
 617 refreshCheckDigest(const StoreEntry * entry, time_t delta)
 618 {
 619     int reason = refreshCheck(entry,
 620                               entry->mem_obj ? entry->mem_obj->request : NULL,
 621                               delta);
 622     ++ refreshCounts[rcCDigest].total;
 623     ++ refreshCounts[rcCDigest].status[reason];
 624     return (reason < 200) ? 0 : 1;
 625 }
 626 #endif
 627
 628 /**
 629  * Get the configured maximum caching time for objects with this URL
 630  * according to refresh_pattern.
 631  *
 632  * Used by http.cc when generating a upstream requests to ensure that
 633  * responses it is given are fresh enough to be worth caching.
 634  *
 635  * \retval pattern-max if there is a refresh_pattern matching the URL configured.
 636  * \retval REFRESH_DEFAULT_MAX if there are no explicit limits configured
 637  */
 638 time_t
 639 getMaxAge(const char *url)
 640 {
 641     const RefreshPattern *R;
 642     debugs(22, 3, "getMaxAge: '" << url << "'");
 643
 644     if ((R = refreshLimits(url)))
 645         return R->max;
 646     else
 647         return REFRESH_DEFAULT_MAX;
 648 }
 649
 650 static int
 651 refreshCountsStatsEntry(StoreEntry * sentry, struct RefreshCounts &rc, int code, const char *desc)
 652 {
 653     storeAppendPrintf(sentry, "%6d\t%6.2f\t%s\n", rc.status[code], xpercent(rc.status[code], rc.total), desc);
 654     return rc.status[code];
 655 }
 656
 657 static void
 658 refreshCountsStats(StoreEntry * sentry, struct RefreshCounts &rc)
 659 {
 660     if (!rc.total)
 661         return;
 662
 663     storeAppendPrintf(sentry, "\n\n%s histogram:\n", rc.proto);
 664     storeAppendPrintf(sentry, "Count\t%%Total\tCategory\n");
 665
 666     int sum = 0;
 667     sum += refreshCountsStatsEntry(sentry, rc, FRESH_REQUEST_MAX_STALE_ALL, "Fresh: request max-stale wildcard");
 668     sum += refreshCountsStatsEntry(sentry, rc, FRESH_REQUEST_MAX_STALE_VALUE, "Fresh: request max-stale value");
 669     sum += refreshCountsStatsEntry(sentry, rc, FRESH_EXPIRES, "Fresh: expires time not reached");
 670     sum += refreshCountsStatsEntry(sentry, rc, FRESH_LMFACTOR_RULE, "Fresh: refresh_pattern last-mod factor percentage");
 671     sum += refreshCountsStatsEntry(sentry, rc, FRESH_MIN_RULE, "Fresh: refresh_pattern min value");
 672     sum += refreshCountsStatsEntry(sentry, rc, FRESH_OVERRIDE_EXPIRES, "Fresh: refresh_pattern override-expires");
 673     sum += refreshCountsStatsEntry(sentry, rc, FRESH_OVERRIDE_LASTMOD, "Fresh: refresh_pattern override-lastmod");
 674     sum += refreshCountsStatsEntry(sentry, rc, STALE_MUST_REVALIDATE, "Stale: response has must-revalidate");
 675     sum += refreshCountsStatsEntry(sentry, rc, STALE_RELOAD_INTO_IMS, "Stale: changed reload into IMS");
 676     sum += refreshCountsStatsEntry(sentry, rc, STALE_FORCED_RELOAD, "Stale: request has no-cache directive");
 677     sum += refreshCountsStatsEntry(sentry, rc, STALE_EXCEEDS_REQUEST_MAX_AGE_VALUE, "Stale: age exceeds request max-age value");
 678     sum += refreshCountsStatsEntry(sentry, rc, STALE_EXPIRES, "Stale: expires time reached");
 679     sum += refreshCountsStatsEntry(sentry, rc, STALE_MAX_RULE, "Stale: refresh_pattern max age rule");
 680     sum += refreshCountsStatsEntry(sentry, rc, STALE_LMFACTOR_RULE, "Stale: refresh_pattern last-mod factor percentage");
 681     sum += refreshCountsStatsEntry(sentry, rc, STALE_DEFAULT, "Stale: by default");
 682     storeAppendPrintf(sentry, "\n");
 683 }
 684
 685 static void
 686 refreshStats(StoreEntry * sentry)
 687 {
 688     // display per-rule counts of usage and tests
 689     storeAppendPrintf(sentry, "\nRefresh pattern usage:\n\n");
 690     storeAppendPrintf(sentry, "  Used      \tChecks    \t%% Matches\tPattern\n");
 691     for (const RefreshPattern *R = Config.Refresh; R; R = R->next) {
 692         storeAppendPrintf(sentry, "  %10" PRIu64 "\t%10" PRIu64 "\t%6.2f\t%s%s\n",
 693                           R->stats.matchCount,
 694                           R->stats.matchTests,
 695                           xpercent(R->stats.matchCount, R->stats.matchTests),
 696                           (R->pattern.flags&REG_ICASE ? "-i " : ""),
 697                           R->pattern.c_str());
 698     }
 699
 700     int i;
 701     int total = 0;
 702
 703     /* get total usage count */
 704
 705     for (i = 0; i < rcCount; ++i)
 706         total += refreshCounts[i].total;
 707
 708     /* protocol usage histogram */
 709     storeAppendPrintf(sentry, "\nRefreshCheck calls per protocol\n\n");
 710
 711     storeAppendPrintf(sentry, "Protocol\t#Calls\t%%Calls\n");
 712
 713     for (i = 0; i < rcCount; ++i)
 714         storeAppendPrintf(sentry, "%10s\t%6d\t%6.2f\n",
 715                           refreshCounts[i].proto,
 716                           refreshCounts[i].total,
 717                           xpercent(refreshCounts[i].total, total));
 718
 719     /* per protocol histograms */
 720     storeAppendPrintf(sentry, "\n\nRefreshCheck histograms for various protocols\n");
 721
 722     for (i = 0; i < rcCount; ++i)
 723         refreshCountsStats(sentry, refreshCounts[i]);
 724 }
 725
 726 static void
 727 refreshRegisterWithCacheManager(void)
 728 {
 729     Mgr::RegisterAction("refresh", "Refresh Algorithm Statistics", refreshStats, 0, 1);
 730 }
 731
 732 void
 733 refreshInit(void)
 734 {
 735     memset(refreshCounts, 0, sizeof(refreshCounts));
 736     refreshCounts[rcHTTP].proto = "HTTP";
 737     refreshCounts[rcICP].proto = "ICP";
 738 #if USE_HTCP
 739
 740     refreshCounts[rcHTCP].proto = "HTCP";
 741 #endif
 742
 743     refreshCounts[rcStore].proto = "On Store";
 744 #if USE_CACHE_DIGESTS
 745
 746     refreshCounts[rcCDigest].proto = "Cache Digests";
 747 #endif
 748
 749     refreshRegisterWithCacheManager();
 750 }
 751