src/HttpHdrSc.cc

   1 /*
   2  * Copyright (C) 1996-2023 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 90    HTTP Cache Control Header */
  10
  11 #include "squid.h"
  12 #include "base/LookupTable.h"
  13 //#include "HttpHdrSc.h" // pulled in by HttpHdrScTarget.h
  14 #include "HttpHdrScTarget.h"
  15 #include "HttpHeader.h"
  16 #include "HttpHeaderFieldStat.h"
  17 #include "HttpHeaderStat.h"
  18 #include "HttpHeaderTools.h"
  19 #include "Store.h"
  20 #include "StrList.h"
  21 #include "util.h"
  22
  23 #include <map>
  24 #include <vector>
  25
  26 /* this table is used for parsing surrogate control header */
  27 /* order must match that of enum http_hdr_sc_type. The constraint is verified at initialization time */
  28 // TODO: implement constraint
  29 static const LookupTable<http_hdr_sc_type>::Record ScAttrs[] {
  30     {"no-store", SC_NO_STORE},
  31     {"no-store-remote", SC_NO_STORE_REMOTE},
  32     {"max-age", SC_MAX_AGE},
  33     {"content", SC_CONTENT},
  34     {"Other,", SC_OTHER}, /* ',' will protect from matches */
  35     {nullptr, SC_ENUM_END} /* SC_ENUM_END taken as invalid value */
  36 };
  37 LookupTable<http_hdr_sc_type> scLookupTable(SC_ENUM_END, ScAttrs);
  38 std::vector<HttpHeaderFieldStat> scHeaderStats(SC_ENUM_END);
  39
  40 // used when iterating over flags
  41 http_hdr_sc_type &operator++ (http_hdr_sc_type &aHeader)
  42 {
  43     int tmp = static_cast<int>(aHeader);
  44     aHeader = static_cast<http_hdr_sc_type>(++tmp);
  45     return aHeader;
  46 }
  47
  48 void
  49 httpHdrScInitModule(void)
  50 {
  51     // check invariant on ScAttrs
  52     for (int i = 0; ScAttrs[i].name != nullptr; ++i)
  53         assert(i == ScAttrs[i].id);
  54 }
  55
  56 /* implementation */
  57
  58 /* creates an sc object from a 0-terminating string */
  59 HttpHdrSc *
  60 httpHdrScParseCreate(const String & str)
  61 {
  62     HttpHdrSc *sc = new HttpHdrSc();
  63
  64     if (!sc->parse(&str)) {
  65         delete sc;
  66         sc = nullptr;
  67     }
  68
  69     return sc;
  70 }
  71
  72 /* parses a 0-terminating string and inits sc */
  73 bool
  74 HttpHdrSc::parse(const String * str)
  75 {
  76     HttpHdrSc * sc=this;
  77     const char *item;
  78     const char *p;      /* '=' parameter */
  79     const char *pos = nullptr;
  80     const char *target = nullptr; /* ;foo */
  81     const char *temp = nullptr; /* temp buffer */
  82     http_hdr_sc_type type;
  83     int ilen, vlen;
  84     int initiallen;
  85     HttpHdrScTarget *sct;
  86     assert(str);
  87
  88     /* iterate through comma separated list */
  89
  90     while (strListGetItem(str, ',', &item, &ilen, &pos)) {
  91         initiallen = ilen;
  92         vlen = 0;
  93         /* decrease ilen to still match the token for  '=' statements */
  94
  95         if ((p = strchr(item, '=')) && (p - item < ilen)) {
  96             vlen = ilen - (p + 1 - item);
  97             ilen = p - item;
  98             ++p;
  99         }
 100
 101         /* decrease ilen to still match the token for ';' qualified non '=' statements */
 102         else if ((p = strchr(item, ';')) && (p - item < ilen)) {
 103             ilen = p - item;
 104             ++p;
 105         }
 106
 107         /* find type */
 108         type = scLookupTable.lookup(SBuf(item,ilen));
 109
 110         if (type == SC_ENUM_END) {
 111             debugs(90, 2, "unknown control-directive near '" << item << "' in '" << *str << "'");
 112             type = SC_OTHER;
 113         }
 114
 115         /* Is this a targeted directive? */
 116         /* TODO: remove the temporary usage and use memrchr and the information we have instead */
 117         temp = xstrndup (item, initiallen + 1);
 118
 119         if (!((target = strrchr (temp, ';')) && !strchr (target, '"') && *(target + 1) != '\0'))
 120             target = nullptr;
 121         else
 122             ++target;
 123
 124         sct = sc->findTarget(target);
 125
 126         if (!sct) {
 127             // XXX: if parse is left-to-right over field-value this should be emplace_back()
 128             // currently placing on the front reverses the order of headers passed on downstream.
 129             sct = &targets.emplace_front(target);
 130         }
 131
 132         safe_free (temp);
 133
 134         if (sct->isSet(type)) {
 135             if (type != SC_OTHER)
 136                 debugs(90, 2, "ignoring duplicate control-directive near '" << item << "' in '" << *str << "'");
 137
 138             ++ scHeaderStats[type].repCount;
 139
 140             continue;
 141         }
 142
 143         /* process directives */
 144         switch (type) {
 145         case SC_NO_STORE:
 146             sct->noStore(true);
 147             break;
 148
 149         case SC_NO_STORE_REMOTE:
 150             sct->noStoreRemote(true);
 151             break;
 152
 153         case SC_MAX_AGE: {
 154             int ma;
 155             if (p && httpHeaderParseInt(p, &ma)) {
 156                 sct->maxAge(ma);
 157
 158                 if ((p = strchr (p, '+'))) {
 159                     int ms;
 160                     ++p; //skip the + char
 161                     if (httpHeaderParseInt(p, &ms)) {
 162                         sct->maxStale(ms);
 163                     } else {
 164                         debugs(90, 2, "sc: invalid max-stale specs near '" << item << "'");
 165                         sct->clearMaxStale();
 166                         /* leave the max-age alone */
 167                     }
 168                 }
 169             } else {
 170                 debugs(90, 2, "sc: invalid max-age specs near '" << item << "'");
 171                 sct->clearMaxAge();
 172             }
 173
 174             break;
 175         }
 176
 177         case SC_CONTENT:
 178
 179             if ( p && httpHeaderParseQuotedString(p, vlen, &sct->content_)) {
 180                 sct->setMask(SC_CONTENT,true); // ugly but saves a copy
 181             } else {
 182                 debugs(90, 2, "sc: invalid content= quoted string near '" << item << "'");
 183                 sct->clearContent();
 184             }
 185             break;
 186
 187         case SC_OTHER:
 188         default:
 189             break;
 190         }
 191     }
 192
 193     return !sc->targets.empty();
 194 }
 195
 196 /// XXX: this function should be in HttpHdrScTarget.cc
 197 void
 198 HttpHdrScTarget::packInto(Packable * p) const
 199 {
 200     http_hdr_sc_type flag;
 201     int pcount = 0;
 202     assert (p);
 203
 204     for (flag = SC_NO_STORE; flag < SC_ENUM_END; ++flag) {
 205         if (isSet(flag) && flag != SC_OTHER) {
 206
 207             /* print option name */
 208             p->appendf((pcount ? ", %s" : "%s"), ScAttrs[flag].name);
 209
 210             /* handle options with values */
 211
 212             if (flag == SC_MAX_AGE)
 213                 p->appendf("=%d", (int) max_age);
 214
 215             if (flag == SC_CONTENT)
 216                 p->appendf("=\"" SQUIDSTRINGPH "\"", SQUIDSTRINGPRINT(content_));
 217
 218             ++pcount;
 219         }
 220     }
 221
 222     if (hasTarget())
 223         p->appendf(";" SQUIDSTRINGPH, SQUIDSTRINGPRINT(target));
 224 }
 225
 226 void
 227 HttpHdrSc::packInto(Packable * p) const
 228 {
 229     assert(p);
 230     for (const auto &t : targets) {
 231         t.packInto(p);
 232     }
 233 }
 234
 235 /* negative max_age will clean old max_Age setting */
 236 void
 237 HttpHdrSc::setMaxAge(char const *target, int max_age)
 238 {
 239     HttpHdrScTarget *sct = findTarget(target);
 240
 241     if (!sct) {
 242         sct = &targets.emplace_back(target);
 243     }
 244
 245     sct->maxAge(max_age);
 246 }
 247
 248 void
 249 HttpHdrSc::updateStats(StatHist * hist) const
 250 {
 251     for (auto &t : targets) {
 252         t.updateStats(hist);
 253     }
 254 }
 255
 256 void
 257 httpHdrScTargetStatDumper(StoreEntry * sentry, int, double val, double, int count)
 258 {
 259     extern const HttpHeaderStat *dump_stat;     /* argh! */
 260     const int id = (int) val;
 261     const bool valid_id = id >= 0 && id < SC_ENUM_END;
 262     const char *name = valid_id ? ScAttrs[id].name : "INVALID";
 263
 264     if (count || valid_id)
 265         storeAppendPrintf(sentry, "%2d\t %-20s\t %5d\t %6.2f\n",
 266                           id, name, count, xdiv(count, dump_stat->scParsedCount));
 267 }
 268
 269 void
 270 httpHdrScStatDumper(StoreEntry * sentry, int, double val, double, int count)
 271 {
 272     extern const HttpHeaderStat *dump_stat; /* argh! */
 273     const int id = (int) val;
 274     const bool valid_id = id >= 0 && id < SC_ENUM_END;
 275     const char *name = valid_id ? ScAttrs[id].name : "INVALID";
 276
 277     if (count || valid_id)
 278         storeAppendPrintf(sentry, "%2d\t %-20s\t %5d\t %6.2f\n",
 279                           id, name, count, xdiv(count, dump_stat->scParsedCount));
 280 }
 281
 282 HttpHdrScTarget *
 283 HttpHdrSc::findTarget(const char *target)
 284 {
 285     for (auto &sct : targets) {
 286         if (sct.target.cmp(target) == 0)
 287             return &sct;
 288     }
 289
 290     return nullptr;
 291 }
 292
 293 HttpHdrScTarget *
 294 HttpHdrSc::getMergedTarget(const char *ourtarget)
 295 {
 296     HttpHdrScTarget *sctus = findTarget(ourtarget);
 297     HttpHdrScTarget *sctgeneric = findTarget(nullptr);
 298
 299     /* W3C Edge Architecture Specification 1.0 section 3
 300      *
 301      * "If more than one is targeted at a surrogate, the most specific applies.
 302      *  For example,
 303      *    Surrogate-Control: max-age=60, no-store;abc
 304      *  The surrogate that identified itself as 'abc' would apply no-store;
 305      *  others would apply max-age=60.
 306      *
 307      * XXX: the if statements below will *merge* the no-store and max-age settings.
 308      */
 309     if (sctgeneric || sctus) {
 310         HttpHdrScTarget *sctusable = new HttpHdrScTarget(nullptr);
 311
 312         if (sctgeneric)
 313             sctusable->mergeWith(sctgeneric);
 314
 315         if (sctus)
 316             sctusable->mergeWith(sctus);
 317
 318         return sctusable;
 319     }
 320
 321     return nullptr;
 322 }
 323