/*
* $Id$
*
* DEBUG: section 22 Refresh Calculation
* AUTHOR: Harvest Derived
*
* SQUID Web Proxy Cache http://www.squid-cache.org/
* ----------------------------------------------------------
*
* Squid is the result of efforts by numerous individuals from
* the Internet community; see the CONTRIBUTORS file for full
* details. Many organizations have provided support for Squid's
* development; see the SPONSORS file for full details. Squid is
* Copyrighted (C) 2001 by the Regents of the University of
* California; see the COPYRIGHT file for full details. Squid
* incorporates software developed and/or copyrighted by other
* sources; see the CREDITS file for full details.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
*
*/
#ifndef USE_POSIX_REGEX
#define USE_POSIX_REGEX /* put before includes; always use POSIX */
#endif
#include "squid-old.h"
#include "HttpHdrCc.h"
#include "mgr/Registration.h"
#include "Store.h"
#include "MemObject.h"
#include "HttpRequest.h"
#include "HttpReply.h"
#include "SquidTime.h"
typedef enum {
rcHTTP,
rcICP,
#if USE_HTCP
rcHTCP,
#endif
#if USE_CACHE_DIGESTS
rcCDigest,
#endif
rcStore,
rcCount
} refreshCountsEnum;
typedef struct {
bool expires;
bool min;
bool lmfactor;
bool max;
} stale_flags;
/*
* This enumerated list assigns specific values, ala HTTP/FTP status
* codes. All Fresh codes are in the range 100-199 and all stale
* codes are 200-299. We might want to use these codes in logging,
* so best to keep them consistent over time.
*/
enum {
FRESH_REQUEST_MAX_STALE_ALL = 100,
FRESH_REQUEST_MAX_STALE_VALUE,
FRESH_EXPIRES,
FRESH_LMFACTOR_RULE,
FRESH_MIN_RULE,
FRESH_OVERRIDE_EXPIRES,
FRESH_OVERRIDE_LASTMOD,
STALE_MUST_REVALIDATE = 200,
STALE_RELOAD_INTO_IMS,
STALE_FORCED_RELOAD,
STALE_EXCEEDS_REQUEST_MAX_AGE_VALUE,
STALE_EXPIRES,
STALE_MAX_RULE,
STALE_LMFACTOR_RULE,
STALE_MAX_STALE,
STALE_DEFAULT = 299
};
static struct RefreshCounts {
const char *proto;
int total;
int status[STALE_DEFAULT + 1];
}
refreshCounts[rcCount];
/*
* Defaults:
* MIN NONE
* PCT 20%
* MAX 3 days
*/
#define REFRESH_DEFAULT_MIN (time_t)0
#define REFRESH_DEFAULT_PCT 0.20
#define REFRESH_DEFAULT_MAX (time_t)259200
static const refresh_t *refreshUncompiledPattern(const char *);
static OBJH refreshStats;
static int refreshStaleness(const StoreEntry * entry, time_t check_time, const time_t age, const refresh_t * R, stale_flags * sf);
static refresh_t DefaultRefresh;
const refresh_t *
refreshLimits(const char *url)
{
const refresh_t *R;
for (R = Config.Refresh; R; R = R->next) {
if (!regexec(&(R->compiled_pattern), url, 0, 0, 0))
return R;
}
return NULL;
}
static const refresh_t *
refreshUncompiledPattern(const char *pat)
{
const refresh_t *R;
for (R = Config.Refresh; R; R = R->next) {
if (0 == strcmp(R->pattern, pat))
return R;
}
return NULL;
}
/**
* Calculate how stale the response is (or will be at the check_time).
* Staleness calculation is based on the following: (1) response
* expiration time, (2) age greater than configured maximum, (3)
* last-modified factor, and (4) age less than configured minimum.
*
* \retval -1 If the response is fresh.
* \retval >0 Otherwise return it's staleness.
* \retval 0 NOTE return value of 0 means the response is stale.
*
* The 'stale_flags' structure is used to tell the calling function
* _why_ this response is fresh or stale. Its used, for example,
* when the admin wants to override expiration and last-modified
* times.
*/
static int
refreshStaleness(const StoreEntry * entry, time_t check_time, const time_t age, const refresh_t * R, stale_flags * sf)
{
/** \par
* Check for an explicit expiration time (Expires: header).
*/
if (entry->expires > -1) {
sf->expires = true;
if (entry->expires > check_time) {
debugs(22, 3, "FRESH: expires " << entry->expires <<
" >= check_time " << check_time << " ");
return -1;
} else {
debugs(22, 3, "STALE: expires " << entry->expires <<
" < check_time " << check_time << " ");
return (check_time - entry->expires);
}
}
/** \par
* Use local heuristics to determine staleness. Start with the
* max age from the refresh_pattern rule.
*/
if (age > R->max) {
debugs(22, 3, "STALE: age " << age << " > max " << R->max << " ");
sf->max = true;
return (age - R->max);
}
/** \par
* Try the last-modified factor algorithm: refresh_pattern n% percentage of Last-Modified: age.
*/
if (entry->lastmod > -1 && entry->timestamp > entry->lastmod) {
/*
* stale_age is the Age of the response when it became/becomes
* stale according to the last-modified factor algorithm.
*/
time_t stale_age = static_cast<time_t>((entry->timestamp - entry->lastmod) * R->pct);
sf->lmfactor = true;
if (age >= stale_age) {
debugs(22, 3, "STALE: age " << age << " > stale_age " << stale_age);
return (age - stale_age);
} else {
debugs(22, 3, "FRESH: age " << age << " <= stale_age " << stale_age);
return -1;
}
}
/** \par
* Finally, if all else fails; staleness is determined by the refresh_pattern
* configured minimum age.
*/
if (age < R->min) {
debugs(22, 3, "FRESH: age " << age << " < min " << R->min);
sf->min = true;
return -1;
}
debugs(22, 3, "STALE: age " << age << " >= min " << R->min);
return (age - R->min);
}
/**
* \retval 1 if the entry must be revalidated within delta seconds
* \retval 0 otherwise
*
* note: request maybe null (e.g. for cache digests build)
*/
static int
refreshCheck(const StoreEntry * entry, HttpRequest * request, time_t delta)
{
const refresh_t *R;
const char *uri = NULL;
time_t age = 0;
time_t check_time = squid_curtime + delta;
int staleness;
stale_flags sf;
if (entry->mem_obj)
uri = entry->mem_obj->url;
else if (request)
uri = urlCanonical(request);
debugs(22, 3, "refreshCheck: '" << (uri ? uri : "<none>") << "'");
if (check_time > entry->timestamp)
age = check_time - entry->timestamp;
// FIXME: what to do when age < 0 or counter overflow?
assert(age >= 0);
R = uri ? refreshLimits(uri) : refreshUncompiledPattern(".");
if (NULL == R)
R = &DefaultRefresh;
debugs(22, 3, "refreshCheck: Matched '" << R->pattern << " " <<
(int) R->min << " " << (int) (100.0 * R->pct) << "%% " <<
(int) R->max << "'");
debugs(22, 3, "\tage:\t" << age);
debugs(22, 3, "\tcheck_time:\t" << mkrfc1123(check_time));
debugs(22, 3, "\tentry->timestamp:\t" << mkrfc1123(entry->timestamp));
if (request && !request->flags.ignore_cc) {
const HttpHdrCc *const cc = request->cache_control;
if (cc && cc->hasMinFresh()) {
const int32_t minFresh=cc->minFresh();
debugs(22, 3, "\tage + min-fresh:\t" << age << " + " <<
minFresh << " = " << age + minFresh);
debugs(22, 3, "\tcheck_time + min-fresh:\t" << check_time << " + "
<< minFresh << " = " <<
mkrfc1123(check_time + minFresh));
age += minFresh;
check_time += minFresh;
}
}
memset(&sf, '\0', sizeof(sf));
staleness = refreshStaleness(entry, check_time, age, R, &sf);
debugs(22, 3, "Staleness = " << staleness);
// stale-if-error requires any failure be passed thru when its period is over.
if (request && entry->mem_obj && entry->mem_obj->getReply() && entry->mem_obj->getReply()->cache_control &&
entry->mem_obj->getReply()->cache_control->hasStaleIfError() &&
entry->mem_obj->getReply()->cache_control->staleIfError() < staleness) {
debugs(22, 3, "refreshCheck: stale-if-error period expired.");
request->flags.fail_on_validation_err = 1;
}
if (EBIT_TEST(entry->flags, ENTRY_REVALIDATE) && staleness > -1
#if USE_HTTP_VIOLATIONS
&& !R->flags.ignore_must_revalidate
#endif
) {
debugs(22, 3, "refreshCheck: YES: Must revalidate stale response");
if (request)
request->flags.fail_on_validation_err = 1;
return STALE_MUST_REVALIDATE;
}
/* request-specific checks */
if (request && !request->flags.ignore_cc) {
HttpHdrCc *cc = request->cache_control;
if (request->flags.ims && (R->flags.refresh_ims || Config.onoff.refresh_all_ims)) {
/* The clients no-cache header is changed into a IMS query */
debugs(22, 3, "refreshCheck: YES: refresh-ims");
return STALE_FORCED_RELOAD;
}
#if USE_HTTP_VIOLATIONS
if (!request->flags.nocache_hack) {
(void) 0;
} else if (R->flags.ignore_reload) {
/* The clients no-cache header is ignored */
debugs(22, 3, "refreshCheck: MAYBE: ignore-reload");
} else if (R->flags.reload_into_ims || Config.onoff.reload_into_ims) {
/* The clients no-cache header is changed into a IMS query */
debugs(22, 3, "refreshCheck: YES: reload-into-ims");
return STALE_RELOAD_INTO_IMS;
} else {
/* The clients no-cache header is not overridden on this request */
debugs(22, 3, "refreshCheck: YES: client reload");
request->flags.nocache = 1;
return STALE_FORCED_RELOAD;
}
#endif
if (NULL != cc) {
if (cc->hasMaxAge()) {
#if USE_HTTP_VIOLATIONS
if (R->flags.ignore_reload && cc->maxAge() == 0) {
debugs(22, 3, "refreshCheck: MAYBE: client-max-age = 0 and ignore-reload");
} else
#endif
{
if (cc->maxAge() == 0) {
debugs(22, 3, "refreshCheck: YES: client-max-age = 0");
return STALE_EXCEEDS_REQUEST_MAX_AGE_VALUE;
}
if (age > cc->maxAge()) {
debugs(22, 3, "refreshCheck: YES: age > client-max-age");
return STALE_EXCEEDS_REQUEST_MAX_AGE_VALUE;
}
}
}
if (cc->hasMaxStale() && staleness > -1) {
if (cc->maxStale()==HttpHdrCc::MAX_STALE_ANY) {
/* max-stale directive without a value */
debugs(22, 3, "refreshCheck: NO: max-stale wildcard");
return FRESH_REQUEST_MAX_STALE_ALL;
} else if (staleness < cc->maxStale()) {
debugs(22, 3, "refreshCheck: NO: staleness < max-stale");
return FRESH_REQUEST_MAX_STALE_VALUE;
}
}
}
}
if (-1 == staleness) {
debugs(22, 3, "refreshCheck: object isn't stale..");
if (sf.expires) {
debugs(22, 3, "refreshCheck: returning FRESH_EXPIRES");
return FRESH_EXPIRES;
}
assert(!sf.max);
if (sf.lmfactor) {
debugs(22, 3, "refreshCheck: returning FRESH_LMFACTOR_RULE");
return FRESH_LMFACTOR_RULE;
}
assert(sf.min);
debugs(22, 3, "refreshCheck: returning FRESH_MIN_RULE");
return FRESH_MIN_RULE;
}
/*
* At this point the response is stale, unless one of
* the override options kicks in.
* NOTE: max-stale config blocks the overrides.
*/
int max_stale = (R->max_stale >= 0 ? R->max_stale : Config.maxStale);
if ( max_stale >= 0 && staleness > max_stale) {
debugs(22, 3, "refreshCheck: YES: max-stale limit");
if (request)
request->flags.fail_on_validation_err = 1;
return STALE_MAX_STALE;
}
if (sf.expires) {
#if USE_HTTP_VIOLATIONS
if (R->flags.override_expire && age < R->min) {
debugs(22, 3, "refreshCheck: NO: age < min && override-expire");
return FRESH_OVERRIDE_EXPIRES;
}
#endif
return STALE_EXPIRES;
}
if (sf.max)
return STALE_MAX_RULE;
if (sf.lmfactor) {
#if USE_HTTP_VIOLATIONS
if (R->flags.override_lastmod && age < R->min) {
debugs(22, 3, "refreshCheck: NO: age < min && override-lastmod");
return FRESH_OVERRIDE_LASTMOD;
}
#endif
return STALE_LMFACTOR_RULE;
}
debugs(22, 3, "refreshCheck: returning STALE_DEFAULT");
return STALE_DEFAULT;
}
int
refreshIsCachable(const StoreEntry * entry)
{
/*
* Don't look at the request to avoid no-cache and other nuisances.
* the object should have a mem_obj so the URL will be found there.
* minimum_expiry_time seconds delta (defaults to 60 seconds), to
* avoid objects which expire almost immediately, and which can't
* be refreshed.
*/
int reason = refreshCheck(entry, NULL, Config.minimum_expiry_time);
++ refreshCounts[rcStore].total;
++ refreshCounts[rcStore].status[reason];
if (reason < STALE_MUST_REVALIDATE)
/* Does not need refresh. This is certainly cachable */
return 1;
if (entry->lastmod < 0)
/* Last modified is needed to do a refresh */
return 0;
if (entry->mem_obj == NULL)
/* no mem_obj? */
return 1;
if (entry->getReply() == NULL)
/* no reply? */
return 1;
if (entry->getReply()->content_length == 0)
/* No use refreshing (caching?) 0 byte objects */
return 0;
/* This seems to be refreshable. Cache it */
return 1;
}
/// whether reply is stale if it is a hit
static bool
refreshIsStaleIfHit(const int reason)
{
switch (reason) {
case FRESH_MIN_RULE:
case FRESH_LMFACTOR_RULE:
case FRESH_EXPIRES:
return false;
default:
return true;
}
}
/* refreshCheck... functions below are protocol-specific wrappers around
* refreshCheck() function above */
int
refreshCheckHTTP(const StoreEntry * entry, HttpRequest * request)
{
int reason = refreshCheck(entry, request, 0);
++ refreshCounts[rcHTTP].total;
++ refreshCounts[rcHTTP].status[reason];
request->flags.stale_if_hit = refreshIsStaleIfHit(reason);
return (Config.onoff.offline || reason < 200) ? 0 : 1;
}
int
refreshCheckICP(const StoreEntry * entry, HttpRequest * request)
{
int reason = refreshCheck(entry, request, 30);
++ refreshCounts[rcICP].total;
++ refreshCounts[rcICP].status[reason];
return (reason < 200) ? 0 : 1;
}
#if USE_HTCP
int
refreshCheckHTCP(const StoreEntry * entry, HttpRequest * request)
{
int reason = refreshCheck(entry, request, 10);
++ refreshCounts[rcHTCP].total;
++ refreshCounts[rcHTCP].status[reason];
return (reason < 200) ? 0 : 1;
}
#endif
#if USE_CACHE_DIGESTS
int
refreshCheckDigest(const StoreEntry * entry, time_t delta)
{
int reason = refreshCheck(entry,
entry->mem_obj ? entry->mem_obj->request : NULL,
delta);
++ refreshCounts[rcCDigest].total;
++ refreshCounts[rcCDigest].status[reason];
return (reason < 200) ? 0 : 1;
}
#endif
time_t
getMaxAge(const char *url)
{
const refresh_t *R;
debugs(22, 3, "getMaxAge: '" << url << "'");
if ((R = refreshLimits(url)))
return R->max;
else
return REFRESH_DEFAULT_MAX;
}
static void
refreshCountsStats(StoreEntry * sentry, struct RefreshCounts *rc)
{
int sum = 0;
int tot = rc->total;
storeAppendPrintf(sentry, "\n\n%s histogram:\n", rc->proto);
storeAppendPrintf(sentry, "Count\t%%Total\tCategory\n");
#define refreshCountsStatsEntry(code,desc) { \
storeAppendPrintf(sentry, "%6d\t%6.2f\t%s\n", \
rc->status[code], xpercent(rc->status[code], tot), desc); \
sum += rc->status[code]; \
}
refreshCountsStatsEntry(FRESH_REQUEST_MAX_STALE_ALL,
"Fresh: request max-stale wildcard");
refreshCountsStatsEntry(FRESH_REQUEST_MAX_STALE_VALUE,
"Fresh: request max-stale value");
refreshCountsStatsEntry(FRESH_EXPIRES,
"Fresh: expires time not reached");
refreshCountsStatsEntry(FRESH_LMFACTOR_RULE,
"Fresh: refresh_pattern last-mod factor percentage");
refreshCountsStatsEntry(FRESH_MIN_RULE,
"Fresh: refresh_pattern min value");
refreshCountsStatsEntry(FRESH_OVERRIDE_EXPIRES,
"Fresh: refresh_pattern override expires");
refreshCountsStatsEntry(FRESH_OVERRIDE_LASTMOD,
"Fresh: refresh_pattern override lastmod");
refreshCountsStatsEntry(STALE_MUST_REVALIDATE,
"Stale: response has must-revalidate");
refreshCountsStatsEntry(STALE_RELOAD_INTO_IMS,
"Stale: changed reload into IMS");
refreshCountsStatsEntry(STALE_FORCED_RELOAD,
"Stale: request has no-cache directive");
refreshCountsStatsEntry(STALE_EXCEEDS_REQUEST_MAX_AGE_VALUE,
"Stale: age exceeds request max-age value");
refreshCountsStatsEntry(STALE_EXPIRES,
"Stale: expires time reached");
refreshCountsStatsEntry(STALE_MAX_RULE,
"Stale: refresh_pattern max age rule");
refreshCountsStatsEntry(STALE_LMFACTOR_RULE,
"Stale: refresh_pattern last-mod factor percentage");
refreshCountsStatsEntry(STALE_DEFAULT,
"Stale: by default");
tot = sum; /* paranoid: "total" line shows 100% if we forgot nothing */
storeAppendPrintf(sentry, "%6d\t%6.2f\tTOTAL\n",
rc->total, xpercent(rc->total, tot));
\
storeAppendPrintf(sentry, "\n");
}
static void
refreshStats(StoreEntry * sentry)
{
int i;
int total = 0;
/* get total usage count */
for (i = 0; i < rcCount; ++i)
total += refreshCounts[i].total;
/* protocol usage histogram */
storeAppendPrintf(sentry, "\nRefreshCheck calls per protocol\n\n");
storeAppendPrintf(sentry, "Protocol\t#Calls\t%%Calls\n");
for (i = 0; i < rcCount; ++i)
storeAppendPrintf(sentry, "%10s\t%6d\t%6.2f\n",
refreshCounts[i].proto,
refreshCounts[i].total,
xpercent(refreshCounts[i].total, total));
/* per protocol histograms */
storeAppendPrintf(sentry, "\n\nRefreshCheck histograms for various protocols\n");
for (i = 0; i < rcCount; ++i)
refreshCountsStats(sentry, &refreshCounts[i]);
}
static void
refreshRegisterWithCacheManager(void)
{
Mgr::RegisterAction("refresh", "Refresh Algorithm Statistics", refreshStats, 0, 1);
}
void
refreshInit(void)
{
memset(refreshCounts, 0, sizeof(refreshCounts));
refreshCounts[rcHTTP].proto = "HTTP";
refreshCounts[rcICP].proto = "ICP";
#if USE_HTCP
refreshCounts[rcHTCP].proto = "HTCP";
#endif
refreshCounts[rcStore].proto = "On Store";
#if USE_CACHE_DIGESTS
refreshCounts[rcCDigest].proto = "Cache Digests";
#endif
memset(&DefaultRefresh, '\0', sizeof(DefaultRefresh));
DefaultRefresh.pattern = "<none>";
DefaultRefresh.min = REFRESH_DEFAULT_MIN;
DefaultRefresh.pct = REFRESH_DEFAULT_PCT;
DefaultRefresh.max = REFRESH_DEFAULT_MAX;
refreshRegisterWithCacheManager();
}