src/ipcache.cc

   1
   2 /*
   3  * $Id: ipcache.cc,v 1.251 2005/04/18 21:52:42 hno Exp $
   4  *
   5  * DEBUG: section 14    IP Cache
   6  * AUTHOR: Harvest Derived
   7  *
   8  * SQUID Web Proxy Cache          http://www.squid-cache.org/
   9  * ----------------------------------------------------------
  10  *
  11  *  Squid is the result of efforts by numerous individuals from
  12  *  the Internet community; see the CONTRIBUTORS file for full
  13  *  details.   Many organizations have provided support for Squid's
  14  *  development; see the SPONSORS file for full details.  Squid is
  15  *  Copyrighted (C) 2001 by the Regents of the University of
  16  *  California; see the COPYRIGHT file for full details.  Squid
  17  *  incorporates software developed and/or copyrighted by other
  18  *  sources; see the CREDITS file for full details.
  19  *
  20  *  This program is free software; you can redistribute it and/or modify
  21  *  it under the terms of the GNU General Public License as published by
  22  *  the Free Software Foundation; either version 2 of the License, or
  23  *  (at your option) any later version.
  24  *
  25  *  This program is distributed in the hope that it will be useful,
  26  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  27  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  28  *  GNU General Public License for more details.
  29  *
  30  *  You should have received a copy of the GNU General Public License
  31  *  along with this program; if not, write to the Free Software
  32  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
  33  *
  34  */
  35
  36 #include "squid.h"
  37 #include "Store.h"
  38
  39 typedef struct _ipcache_entry ipcache_entry;
  40
  41 struct _ipcache_entry
  42 {
  43     hash_link hash;             /* must be first */
  44     time_t lastref;
  45     time_t expires;
  46     ipcache_addrs addrs;
  47     IPH *handler;
  48     void *handlerData;
  49     char *error_message;
  50
  51     struct timeval request_time;
  52     dlink_node lru;
  53     unsigned short locks;
  54
  55     struct
  56     {
  57
  58 unsigned int negcached:
  59         1;
  60
  61 unsigned int fromhosts:
  62         1;
  63     }
  64
  65     flags;
  66 };
  67
  68 static struct
  69 {
  70     int requests;
  71     int replies;
  72     int hits;
  73     int misses;
  74     int negative_hits;
  75 }
  76
  77 IpcacheStats;
  78
  79 static dlink_list lru_list;
  80
  81 static FREE ipcacheFreeEntry;
  82 #if USE_DNSSERVERS
  83 static HLPCB ipcacheHandleReply;
  84 #else
  85 static IDNSCB ipcacheHandleReply;
  86 #endif
  87 static IPH dummy_handler;
  88 static int ipcacheExpiredEntry(ipcache_entry *);
  89 static int ipcache_testname(void);
  90 #if USE_DNSSERVERS
  91 static int ipcacheParse(ipcache_entry *, const char *buf);
  92 #else
  93 static int ipcacheParse(ipcache_entry *, rfc1035_rr *, int, const char *error);
  94 #endif
  95 static ipcache_entry *ipcache_get(const char *);
  96 static void ipcacheLockEntry(ipcache_entry *);
  97 static void ipcacheStatPrint(ipcache_entry *, StoreEntry *);
  98 static void ipcacheUnlockEntry(ipcache_entry *);
  99 static void ipcacheRelease(ipcache_entry *);
 100
 101 static ipcache_addrs static_addrs;
 102 static hash_table *ip_table = NULL;
 103
 104 static long ipcache_low = 180;
 105 static long ipcache_high = 200;
 106
 107 #if LIBRESOLV_DNS_TTL_HACK
 108 extern int _dns_ttl_;
 109 #endif
 110
 111 static int
 112 ipcache_testname(void)
 113 {
 114     wordlist *w = NULL;
 115     debug(14, 1) ("Performing DNS Tests...\n");
 116
 117     if ((w = Config.dns_testname_list) == NULL)
 118         return 1;
 119
 120     for (; w; w = w->next) {
 121         if (gethostbyname(w->key) != NULL)
 122             return 1;
 123     }
 124
 125     return 0;
 126 }
 127
 128 /* removes the given ipcache entry */
 129 static void
 130 ipcacheRelease(ipcache_entry * i)
 131 {
 132     debug(14, 3) ("ipcacheRelease: Releasing entry for '%s'\n", (const char *) i->hash.key);
 133     hash_remove_link(ip_table, (hash_link *) i);
 134     dlinkDelete(&i->lru, &lru_list);
 135     ipcacheFreeEntry(i);
 136 }
 137
 138 static ipcache_entry *
 139 ipcache_get(const char *name)
 140 {
 141     if (ip_table != NULL)
 142         return (ipcache_entry *) hash_lookup(ip_table, name);
 143     else
 144         return NULL;
 145 }
 146
 147 static int
 148 ipcacheExpiredEntry(ipcache_entry * i)
 149 {
 150     /* all static entries are locked, so this takes care of them too */
 151
 152     if (i->locks != 0)
 153         return 0;
 154
 155     if (i->addrs.count == 0)
 156         if (0 == i->flags.negcached)
 157             return 1;
 158
 159     if (i->expires > squid_curtime)
 160         return 0;
 161
 162     return 1;
 163 }
 164
 165 void
 166 ipcache_purgelru(void *voidnotused)
 167 {
 168     dlink_node *m;
 169     dlink_node *prev = NULL;
 170     ipcache_entry *i;
 171     int removed = 0;
 172     eventAdd("ipcache_purgelru", ipcache_purgelru, NULL, 10.0, 1);
 173
 174     for (m = lru_list.tail; m; m = prev) {
 175         if (memInUse(MEM_IPCACHE_ENTRY) < ipcache_low)
 176             break;
 177
 178         prev = m->prev;
 179
 180         i = (ipcache_entry *)m->data;
 181
 182         if (i->locks != 0)
 183             continue;
 184
 185         ipcacheRelease(i);
 186
 187         removed++;
 188     }
 189
 190     debug(14, 9) ("ipcache_purgelru: removed %d entries\n", removed);
 191 }
 192
 193 /* purges entries added from /etc/hosts (or whatever). */
 194 static void
 195 purge_entries_fromhosts(void)
 196 {
 197     dlink_node *m = lru_list.head;
 198     ipcache_entry *i = NULL, *t;
 199
 200     while (m) {
 201         if (i != NULL) {        /* need to delay deletion */
 202             ipcacheRelease(i);  /* we just override locks */
 203             i = NULL;
 204         }
 205
 206         t = (ipcache_entry*)m->data;
 207
 208         if (t->flags.fromhosts)
 209             i = t;
 210
 211         m = m->next;
 212     }
 213
 214     if (i != NULL)
 215         ipcacheRelease(i);
 216 }
 217
 218 /* create blank ipcache_entry */
 219 static ipcache_entry *
 220 ipcacheCreateEntry(const char *name)
 221 {
 222     static ipcache_entry *i;
 223     i = (ipcache_entry *)memAllocate(MEM_IPCACHE_ENTRY);
 224     i->hash.key = xstrdup(name);
 225     i->expires = squid_curtime + Config.negativeDnsTtl;
 226     return i;
 227 }
 228
 229 static void
 230 ipcacheAddEntry(ipcache_entry * i)
 231 {
 232     hash_link *e = (hash_link *)hash_lookup(ip_table, i->hash.key);
 233
 234     if (NULL != e) {
 235         /* avoid colission */
 236         ipcache_entry *q = (ipcache_entry *) e;
 237         ipcacheRelease(q);
 238     }
 239
 240     hash_join(ip_table, &i->hash);
 241     dlinkAdd(i, &i->lru, &lru_list);
 242     i->lastref = squid_curtime;
 243 }
 244
 245 /* walks down the pending list, calling handlers */
 246 static void
 247 ipcacheCallback(ipcache_entry * i)
 248 {
 249     IPH *callback = i->handler;
 250     void *cbdata;
 251     i->lastref = squid_curtime;
 252
 253     if (!i->handler)
 254         return;
 255
 256     ipcacheLockEntry(i);
 257
 258     callback = i->handler;
 259
 260     i->handler = NULL;
 261
 262     if (cbdataReferenceValidDone(i->handlerData, &cbdata)) {
 263         dns_error_message = i->error_message;
 264         callback(i->flags.negcached ? NULL : &i->addrs, cbdata);
 265     }
 266
 267     ipcacheUnlockEntry(i);
 268 }
 269
 270 #if USE_DNSSERVERS
 271 static int
 272 ipcacheParse(ipcache_entry *i, const char *inbuf)
 273 {
 274     LOCAL_ARRAY(char, buf, DNS_INBUF_SZ);
 275     char *token;
 276     int ipcount = 0;
 277     int ttl;
 278     char *A[32];
 279     const char *name = (const char *)i->hash.key;
 280     i->expires = squid_curtime + Config.negativeDnsTtl;
 281     i->flags.negcached = 1;
 282     safe_free(i->addrs.in_addrs);
 283     safe_free(i->addrs.bad_mask);
 284     safe_free(i->error_message);
 285     i->addrs.count = 0;
 286
 287     if (inbuf == NULL) {
 288         debug(14, 1) ("ipcacheParse: Got <NULL> reply\n");
 289         i->error_message = xstrdup("Internal Error");
 290         return -1;
 291     }
 292
 293     xstrncpy(buf, inbuf, DNS_INBUF_SZ);
 294     debug(14, 5) ("ipcacheParse: parsing: {%s}\n", buf);
 295     token = strtok(buf, w_space);
 296
 297     if (NULL == token) {
 298         debug(14, 1) ("ipcacheParse: expecting result, got '%s'\n", inbuf);
 299         i->error_message = xstrdup("Internal Error");
 300         return -1;
 301     }
 302
 303     if (0 == strcmp(token, "$fail")) {
 304         token = strtok(NULL, "\n");
 305         assert(NULL != token);
 306         i->error_message = xstrdup(token);
 307         return 0;
 308     }
 309
 310     if (0 != strcmp(token, "$addr")) {
 311         debug(14, 1) ("ipcacheParse: expecting '$addr', got '%s' in response to '%s'\n", inbuf, name);
 312         i->error_message = xstrdup("Internal Error");
 313         return -1;
 314     }
 315
 316     token = strtok(NULL, w_space);
 317
 318     if (NULL == token) {
 319         debug(14, 1) ("ipcacheParse: expecting TTL, got '%s' in response to '%s'\n", inbuf, name);
 320         i->error_message = xstrdup("Internal Error");
 321         return -1;
 322     }
 323
 324     ttl = atoi(token);
 325
 326     while (NULL != (token = strtok(NULL, w_space))) {
 327         A[ipcount] = token;
 328
 329         if (++ipcount == 32)
 330             break;
 331     }
 332
 333     if (ipcount > 0) {
 334         int j, k;
 335
 336         i->addrs.in_addrs = (struct IN_ADDR *)xcalloc(ipcount, sizeof(struct IN_ADDR));
 337         i->addrs.bad_mask = (unsigned char *)xcalloc(ipcount, sizeof(unsigned char));
 338
 339         for (j = 0, k = 0; k < ipcount; k++) {
 340             if (safe_inet_addr(A[k], &i->addrs.in_addrs[j]))
 341                 j++;
 342             else
 343                 debug(14, 1) ("ipcacheParse: Invalid IP address '%s' in response to '%s'\n", A[k], name);
 344         }
 345
 346         i->addrs.count = (unsigned char) j;
 347     }
 348
 349     if (i->addrs.count <= 0) {
 350         debug(14, 1) ("ipcacheParse: No addresses in response to '%s'\n", name);
 351         return -1;
 352     }
 353
 354     if (ttl == 0 || ttl > Config.positiveDnsTtl)
 355         ttl = Config.positiveDnsTtl;
 356
 357     if (ttl < Config.negativeDnsTtl)
 358         ttl = Config.negativeDnsTtl;
 359
 360     i->expires = squid_curtime + ttl;
 361
 362     i->flags.negcached = 0;
 363
 364     return i->addrs.count;
 365 }
 366
 367 #else
 368 static int
 369 ipcacheParse(ipcache_entry *i, rfc1035_rr * answers, int nr, const char *error_message)
 370 {
 371     int k;
 372     int j;
 373     int na = 0;
 374     int ttl = 0;
 375     const char *name = (const char *)i->hash.key;
 376     i->expires = squid_curtime + Config.negativeDnsTtl;
 377     i->flags.negcached = 1;
 378     safe_free(i->addrs.in_addrs);
 379     safe_free(i->addrs.bad_mask);
 380     safe_free(i->error_message);
 381     i->addrs.count = 0;
 382
 383     if (nr < 0) {
 384         debug(14, 3) ("ipcacheParse: Lookup failed '%s' for '%s'\n",
 385                       error_message, (const char *)i->hash.key);
 386         i->error_message = xstrdup(error_message);
 387         return -1;
 388     }
 389
 390     if (nr == 0) {
 391         debug(14, 3) ("ipcacheParse: No DNS records in response to '%s'\n", name);
 392         i->error_message = xstrdup("No DNS records");
 393         return 0;
 394     }
 395
 396     assert(answers);
 397
 398     for (k = 0; k < nr; k++) {
 399         if (answers[k].type != RFC1035_TYPE_A)
 400             continue;
 401
 402         if (answers[k]._class != RFC1035_CLASS_IN)
 403             continue;
 404
 405         if (answers[k].rdlength != 4) {
 406             debug(14, 1)("ipcacheParse: Invalid IP address in response to '%s'\n", name);
 407             continue;
 408         }
 409
 410         na++;
 411     }
 412
 413     if (na == 0) {
 414         debug(14, 1) ("ipcacheParse: No Address records in response to '%s'\n", name);
 415         i->error_message = xstrdup("No Address records");
 416         return 0;
 417     }
 418
 419     i->addrs.in_addrs = (struct IN_ADDR *)xcalloc(na, sizeof(struct IN_ADDR));
 420     i->addrs.bad_mask = (unsigned char *)xcalloc(na, sizeof(unsigned char));
 421
 422     for (j = 0, k = 0; k < nr; k++) {
 423         if (answers[k].type != RFC1035_TYPE_A)
 424             continue;
 425
 426         if (answers[k]._class != RFC1035_CLASS_IN)
 427             continue;
 428
 429         if (answers[k].rdlength != 4)
 430             continue;
 431
 432         if (ttl == 0 || (int) answers[k].ttl < ttl)
 433             ttl = answers[k].ttl;
 434
 435         xmemcpy(&i->addrs.in_addrs[j++], answers[k].rdata, 4);
 436
 437         debug(14, 3) ("ipcacheParse: #%d %s\n",
 438                       j - 1,
 439                       inet_ntoa(i->addrs.in_addrs[j - 1]));
 440     }
 441
 442     assert(j == na);
 443
 444     i->addrs.count = (unsigned char) na;
 445
 446     if (ttl == 0 || ttl > Config.positiveDnsTtl)
 447         ttl = Config.positiveDnsTtl;
 448
 449     if (ttl < Config.negativeDnsTtl)
 450         ttl = Config.negativeDnsTtl;
 451
 452     i->expires = squid_curtime + ttl;
 453
 454     i->flags.negcached = 0;
 455
 456     return i->addrs.count;
 457 }
 458
 459 #endif
 460
 461 static void
 462 #if USE_DNSSERVERS
 463 ipcacheHandleReply(void *data, char *reply)
 464 #else
 465 ipcacheHandleReply(void *data, rfc1035_rr * answers, int na, const char *error_message)
 466 #endif
 467 {
 468     generic_cbdata *c = (generic_cbdata *)data;
 469     ipcache_entry *i = (ipcache_entry *)c->data;
 470     cbdataFree(c);
 471     c = NULL;
 472     IpcacheStats.replies++;
 473     statHistCount(&statCounter.dns.svc_time,
 474                   tvSubMsec(i->request_time, current_time));
 475 #if USE_DNSSERVERS
 476
 477     ipcacheParse(i, reply);
 478 #else
 479
 480     ipcacheParse(i, answers, na, error_message);
 481 #endif
 482
 483     ipcacheAddEntry(i);
 484     ipcacheCallback(i);
 485 }
 486
 487 void
 488 ipcache_nbgethostbyname(const char *name, IPH * handler, void *handlerData)
 489 {
 490     ipcache_entry *i = NULL;
 491     const ipcache_addrs *addrs = NULL;
 492     generic_cbdata *c;
 493     assert(handler != NULL);
 494     debug(14, 4) ("ipcache_nbgethostbyname: Name '%s'.\n", name);
 495     IpcacheStats.requests++;
 496
 497     if (name == NULL || name[0] == '\0') {
 498         debug(14, 4) ("ipcache_nbgethostbyname: Invalid name!\n");
 499         dns_error_message = "Invalid hostname";
 500         handler(NULL, handlerData);
 501         return;
 502     }
 503
 504     if ((addrs = ipcacheCheckNumeric(name))) {
 505         dns_error_message = NULL;
 506         handler(addrs, handlerData);
 507         return;
 508     }
 509
 510     i = ipcache_get(name);
 511
 512     if (NULL == i) {
 513         /* miss */
 514         (void) 0;
 515     } else if (ipcacheExpiredEntry(i)) {
 516         /* hit, but expired -- bummer */
 517         ipcacheRelease(i);
 518         i = NULL;
 519     } else {
 520         /* hit */
 521         debug(14, 4) ("ipcache_nbgethostbyname: HIT for '%s'\n", name);
 522
 523         if (i->flags.negcached)
 524             IpcacheStats.negative_hits++;
 525         else
 526             IpcacheStats.hits++;
 527
 528         i->handler = handler;
 529
 530         i->handlerData = cbdataReference(handlerData);
 531
 532         ipcacheCallback(i);
 533
 534         return;
 535     }
 536
 537     debug(14, 5) ("ipcache_nbgethostbyname: MISS for '%s'\n", name);
 538     IpcacheStats.misses++;
 539     i = ipcacheCreateEntry(name);
 540     i->handler = handler;
 541     i->handlerData = cbdataReference(handlerData);
 542     i->request_time = current_time;
 543     c = cbdataAlloc(generic_cbdata);
 544     c->data = i;
 545 #if USE_DNSSERVERS
 546
 547     dnsSubmit(hashKeyStr(&i->hash), ipcacheHandleReply, c);
 548 #else
 549
 550     idnsALookup(hashKeyStr(&i->hash), ipcacheHandleReply, c);
 551 #endif
 552 }
 553
 554 /* initialize the ipcache */
 555 void
 556 ipcache_init(void)
 557 {
 558     int n;
 559     debug(14, 3) ("Initializing IP Cache...\n");
 560     memset(&IpcacheStats, '\0', sizeof(IpcacheStats));
 561     memset(&lru_list, '\0', sizeof(lru_list));
 562     /* test naming lookup */
 563
 564     if (!opt_dns_tests) {
 565         debug(14, 4) ("ipcache_init: Skipping DNS name lookup tests.\n");
 566     } else if (!ipcache_testname()) {
 567         fatal("ipcache_init: DNS name lookup tests failed.");
 568     } else {
 569         debug(14, 1) ("Successful DNS name lookup tests...\n");
 570     }
 571
 572     memset(&static_addrs, '\0', sizeof(ipcache_addrs));
 573
 574     static_addrs.in_addrs = (struct IN_ADDR *)xcalloc(1, sizeof(struct IN_ADDR));
 575     static_addrs.bad_mask = (unsigned char *)xcalloc(1, sizeof(unsigned char));
 576     ipcache_high = (long) (((float) Config.ipcache.size *
 577                             (float) Config.ipcache.high) / (float) 100);
 578     ipcache_low = (long) (((float) Config.ipcache.size *
 579                            (float) Config.ipcache.low) / (float) 100);
 580     n = hashPrime(ipcache_high / 4);
 581     ip_table = hash_create((HASHCMP *) strcmp, n, hash4);
 582     cachemgrRegister("ipcache",
 583                      "IP Cache Stats and Contents",
 584                      stat_ipcache_get, 0, 1);
 585     memDataInit(MEM_IPCACHE_ENTRY, "ipcache_entry", sizeof(ipcache_entry), 0);
 586 }
 587
 588 const ipcache_addrs *
 589 ipcache_gethostbyname(const char *name, int flags)
 590 {
 591     ipcache_entry *i = NULL;
 592     ipcache_addrs *addrs;
 593     assert(name);
 594     debug(14, 3) ("ipcache_gethostbyname: '%s', flags=%x\n", name, flags);
 595     IpcacheStats.requests++;
 596     i = ipcache_get(name);
 597
 598     if (NULL == i) {
 599         (void) 0;
 600     } else if (ipcacheExpiredEntry(i)) {
 601         ipcacheRelease(i);
 602         i = NULL;
 603     } else if (i->flags.negcached) {
 604         IpcacheStats.negative_hits++;
 605         dns_error_message = i->error_message;
 606         return NULL;
 607     } else {
 608         IpcacheStats.hits++;
 609         i->lastref = squid_curtime;
 610         dns_error_message = i->error_message;
 611         return &i->addrs;
 612     }
 613
 614     dns_error_message = NULL;
 615
 616     if ((addrs = ipcacheCheckNumeric(name)))
 617         return addrs;
 618
 619     IpcacheStats.misses++;
 620
 621     if (flags & IP_LOOKUP_IF_MISS)
 622         ipcache_nbgethostbyname(name, dummy_handler, NULL);
 623
 624     return NULL;
 625 }
 626
 627 static void
 628 ipcacheStatPrint(ipcache_entry * i, StoreEntry * sentry)
 629 {
 630     int k;
 631     storeAppendPrintf(sentry, " %-32.32s %c%c %6d %6d %2d(%2d)",
 632                       hashKeyStr(&i->hash),
 633                       i->flags.fromhosts ? 'H' : ' ',
 634                       i->flags.negcached ? 'N' : ' ',
 635                       (int) (squid_curtime - i->lastref),
 636                       (int) ((i->flags.fromhosts ? -1 : i->expires - squid_curtime)),
 637                       (int) i->addrs.count,
 638                       (int) i->addrs.badcount);
 639
 640     for (k = 0; k < (int) i->addrs.count; k++) {
 641         storeAppendPrintf(sentry, " %15s-%3s", inet_ntoa(i->addrs.in_addrs[k]),
 642                           i->addrs.bad_mask[k] ? "BAD" : "OK ");
 643     }
 644
 645     storeAppendPrintf(sentry, "\n");
 646 }
 647
 648 /* process objects list */
 649 void
 650 stat_ipcache_get(StoreEntry * sentry)
 651 {
 652     dlink_node *m;
 653     assert(ip_table != NULL);
 654     storeAppendPrintf(sentry, "IP Cache Statistics:\n");
 655     storeAppendPrintf(sentry, "IPcache Entries: %d\n",
 656                       memInUse(MEM_IPCACHE_ENTRY));
 657     storeAppendPrintf(sentry, "IPcache Requests: %d\n",
 658                       IpcacheStats.requests);
 659     storeAppendPrintf(sentry, "IPcache Hits: %d\n",
 660                       IpcacheStats.hits);
 661     storeAppendPrintf(sentry, "IPcache Negative Hits: %d\n",
 662                       IpcacheStats.negative_hits);
 663     storeAppendPrintf(sentry, "IPcache Misses: %d\n",
 664                       IpcacheStats.misses);
 665     storeAppendPrintf(sentry, "\n\n");
 666     storeAppendPrintf(sentry, "IP Cache Contents:\n\n");
 667     storeAppendPrintf(sentry, " %-29.29s %3s %6s %6s %1s\n",
 668                       "Hostname",
 669                       "Flg",
 670                       "lstref",
 671                       "TTL",
 672                       "N");
 673
 674     for (m = lru_list.head; m; m = m->next)
 675         ipcacheStatPrint((ipcache_entry *)m->data, sentry);
 676 }
 677
 678 static void
 679 dummy_handler(const ipcache_addrs * addrsnotused, void *datanotused)
 680 {
 681     return;
 682 }
 683
 684 void
 685 ipcacheInvalidate(const char *name)
 686 {
 687     ipcache_entry *i;
 688
 689     if ((i = ipcache_get(name)) == NULL)
 690         return;
 691
 692     i->expires = squid_curtime;
 693
 694     /*
 695      * NOTE, don't call ipcacheRelease here becuase we might be here due
 696      * to a thread started from a callback.
 697      */
 698 }
 699
 700 void
 701 ipcacheInvalidateNegative(const char *name)
 702 {
 703     ipcache_entry *i;
 704
 705     if ((i = ipcache_get(name)) == NULL)
 706         return;
 707
 708     if (i->flags.negcached)
 709         i->expires = squid_curtime;
 710
 711     /*
 712      * NOTE, don't call ipcacheRelease here becuase we might be here due
 713      * to a thread started from a callback.
 714      */
 715 }
 716
 717 ipcache_addrs *
 718 ipcacheCheckNumeric(const char *name)
 719 {
 720
 721     struct IN_ADDR ip;
 722     /* check if it's already a IP address in text form. */
 723
 724     if (!safe_inet_addr(name, &ip))
 725         return NULL;
 726
 727     static_addrs.count = 1;
 728
 729     static_addrs.cur = 0;
 730
 731     static_addrs.in_addrs[0].s_addr = ip.s_addr;
 732
 733     static_addrs.bad_mask[0] = FALSE;
 734
 735     static_addrs.badcount = 0;
 736
 737     return &static_addrs;
 738 }
 739
 740 static void
 741 ipcacheLockEntry(ipcache_entry * i)
 742 {
 743     if (i->locks++ == 0) {
 744         dlinkDelete(&i->lru, &lru_list);
 745         dlinkAdd(i, &i->lru, &lru_list);
 746     }
 747 }
 748
 749 static void
 750 ipcacheUnlockEntry(ipcache_entry * i)
 751 {
 752     assert(i->locks > 0);
 753     i->locks--;
 754
 755     if (ipcacheExpiredEntry(i))
 756         ipcacheRelease(i);
 757 }
 758
 759 void
 760 ipcacheCycleAddr(const char *name, ipcache_addrs * ia)
 761 {
 762     ipcache_entry *i;
 763     unsigned char k;
 764     assert(name || ia);
 765
 766     if (NULL == ia) {
 767         if ((i = ipcache_get(name)) == NULL)
 768             return;
 769
 770         if (i->flags.negcached)
 771             return;
 772
 773         ia = &i->addrs;
 774     }
 775
 776     for (k = 0; k < ia->count; k++) {
 777         if (++ia->cur == ia->count)
 778             ia->cur = 0;
 779
 780         if (!ia->bad_mask[ia->cur])
 781             break;
 782     }
 783
 784     if (k == ia->count) {
 785         /* All bad, reset to All good */
 786         debug(14, 3) ("ipcacheCycleAddr: Changing ALL %s addrs from BAD to OK\n",
 787                       name);
 788
 789         for (k = 0; k < ia->count; k++)
 790             ia->bad_mask[k] = 0;
 791
 792         ia->badcount = 0;
 793
 794         ia->cur = 0;
 795     }
 796
 797     debug(14, 3) ("ipcacheCycleAddr: %s now at %s\n", name,
 798                   inet_ntoa(ia->in_addrs[ia->cur]));
 799 }
 800
 801 /*
 802  * Marks the given address as BAD and calls ipcacheCycleAddr to
 803  * advance the current pointer to the next OK address.
 804  */
 805 void
 806
 807 ipcacheMarkBadAddr(const char *name, struct IN_ADDR addr)
 808 {
 809     ipcache_entry *i;
 810     ipcache_addrs *ia;
 811     int k;
 812
 813     if ((i = ipcache_get(name)) == NULL)
 814         return;
 815
 816     ia = &i->addrs;
 817
 818     for (k = 0; k < (int) ia->count; k++)
 819     {
 820         if (ia->in_addrs[k].s_addr == addr.s_addr)
 821             break;
 822     }
 823
 824     if (k == (int) ia->count)   /* not found */
 825         return;
 826
 827     if (!ia->bad_mask[k])
 828     {
 829         ia->bad_mask[k] = TRUE;
 830         ia->badcount++;
 831         i->expires = XMIN(squid_curtime + XMAX((time_t)60, Config.negativeDnsTtl), i->expires);
 832         debug(14, 2) ("ipcacheMarkBadAddr: %s [%s]\n", name, inet_ntoa(addr));
 833     }
 834
 835     ipcacheCycleAddr(name, ia);
 836 }
 837
 838 void
 839
 840 ipcacheMarkGoodAddr(const char *name, struct IN_ADDR addr)
 841 {
 842     ipcache_entry *i;
 843     ipcache_addrs *ia;
 844     int k;
 845
 846     if ((i = ipcache_get(name)) == NULL)
 847         return;
 848
 849     ia = &i->addrs;
 850
 851     for (k = 0; k < (int) ia->count; k++)
 852     {
 853         if (ia->in_addrs[k].s_addr == addr.s_addr)
 854             break;
 855     }
 856
 857     if (k == (int) ia->count)   /* not found */
 858         return;
 859
 860     if (!ia->bad_mask[k])       /* already OK */
 861         return;
 862
 863     ia->bad_mask[k] = FALSE;
 864
 865     ia->badcount--;
 866
 867     debug(14, 2) ("ipcacheMarkGoodAddr: %s [%s]\n", name, inet_ntoa(addr));
 868 }
 869
 870 static void
 871 ipcacheFreeEntry(void *data)
 872 {
 873     ipcache_entry *i = (ipcache_entry *)data;
 874     safe_free(i->addrs.in_addrs);
 875     safe_free(i->addrs.bad_mask);
 876     safe_free(i->hash.key);
 877     safe_free(i->error_message);
 878     memFree(i, MEM_IPCACHE_ENTRY);
 879 }
 880
 881 void
 882 ipcacheFreeMemory(void)
 883 {
 884     hashFreeItems(ip_table, ipcacheFreeEntry);
 885     hashFreeMemory(ip_table);
 886     ip_table = NULL;
 887 }
 888
 889 /* Recalculate IP cache size upon reconfigure */
 890 void
 891 ipcache_restart(void)
 892 {
 893     ipcache_high = (long) (((float) Config.ipcache.size *
 894                             (float) Config.ipcache.high) / (float) 100);
 895     ipcache_low = (long) (((float) Config.ipcache.size *
 896                            (float) Config.ipcache.low) / (float) 100);
 897     purge_entries_fromhosts();
 898 }
 899
 900 /*
 901  *  adds a "static" entry from /etc/hosts.
 902  *  returns 0 upon success, 1 if the ip address is invalid
 903  */
 904 int
 905 ipcacheAddEntryFromHosts(const char *name, const char *ipaddr)
 906 {
 907     ipcache_entry *i;
 908
 909     struct IN_ADDR ip;
 910
 911     if (!safe_inet_addr(ipaddr, &ip)) {
 912         if (strchr(ipaddr, ':') && strspn(ipaddr, "0123456789abcdefABCDEF:") == strlen(ipaddr)) {
 913             debug(14, 3) ("ipcacheAddEntryFromHosts: Skipping IPv6 address '%s'\n", ipaddr);
 914         } else {
 915             debug(14, 1) ("ipcacheAddEntryFromHosts: Bad IP address '%s'\n",
 916                           ipaddr);
 917         }
 918
 919         return 1;
 920     }
 921
 922     if ((i = ipcache_get(name))) {
 923         if (1 == i->flags.fromhosts) {
 924             ipcacheUnlockEntry(i);
 925         } else if (i->locks > 0) {
 926             debug(14, 1) ("ipcacheAddEntryFromHosts: can't add static entry"
 927                           " for locked name '%s'\n", name);
 928             return 1;
 929         } else {
 930             ipcacheRelease(i);
 931         }
 932     }
 933
 934     i = ipcacheCreateEntry(name);
 935     i->addrs.count = 1;
 936     i->addrs.cur = 0;
 937     i->addrs.badcount = 0;
 938
 939     i->addrs.in_addrs = (struct IN_ADDR *)xcalloc(1, sizeof(struct IN_ADDR));
 940     i->addrs.bad_mask = (unsigned char *)xcalloc(1, sizeof(unsigned char));
 941     i->addrs.in_addrs[0].s_addr = ip.s_addr;
 942     i->addrs.bad_mask[0] = FALSE;
 943     i->flags.fromhosts = 1;
 944     ipcacheAddEntry(i);
 945     ipcacheLockEntry(i);
 946     return 0;
 947 }
 948
 949 #ifdef SQUID_SNMP
 950 /*
 951  * The function to return the ip cache statistics to via SNMP
 952  */
 953
 954 variable_list *
 955 snmp_netIpFn(variable_list * Var, snint * ErrP)
 956 {
 957     variable_list *Answer = NULL;
 958     debug(49, 5) ("snmp_netIpFn: Processing request:\n");
 959     snmpDebugOid(5, Var->name, Var->name_length);
 960     *ErrP = SNMP_ERR_NOERROR;
 961
 962     switch (Var->name[LEN_SQ_NET + 1]) {
 963
 964     case IP_ENT:
 965         Answer = snmp_var_new_integer(Var->name, Var->name_length,
 966                                       memInUse(MEM_IPCACHE_ENTRY),
 967                                       SMI_GAUGE32);
 968         break;
 969
 970     case IP_REQ:
 971         Answer = snmp_var_new_integer(Var->name, Var->name_length,
 972                                       IpcacheStats.requests,
 973                                       SMI_COUNTER32);
 974         break;
 975
 976     case IP_HITS:
 977         Answer = snmp_var_new_integer(Var->name, Var->name_length,
 978                                       IpcacheStats.hits,
 979                                       SMI_COUNTER32);
 980         break;
 981
 982     case IP_PENDHIT:
 983         Answer = snmp_var_new_integer(Var->name, Var->name_length,
 984                                       0,
 985                                       SMI_GAUGE32);
 986         break;
 987
 988     case IP_NEGHIT:
 989         Answer = snmp_var_new_integer(Var->name, Var->name_length,
 990                                       IpcacheStats.negative_hits,
 991                                       SMI_COUNTER32);
 992         break;
 993
 994     case IP_MISS:
 995         Answer = snmp_var_new_integer(Var->name, Var->name_length,
 996                                       IpcacheStats.misses,
 997                                       SMI_COUNTER32);
 998         break;
 999
1000     case IP_GHBN:
1001         Answer = snmp_var_new_integer(Var->name, Var->name_length,
1002                                       0, /* deprecated */
1003                                       SMI_COUNTER32);
1004         break;
1005
1006     case IP_LOC:
1007         Answer = snmp_var_new_integer(Var->name, Var->name_length,
1008                                       0, /* deprecated */
1009                                       SMI_COUNTER32);
1010         break;
1011
1012     default:
1013         *ErrP = SNMP_ERR_NOSUCHNAME;
1014         snmp_var_free(Answer);
1015         return (NULL);
1016     }
1017
1018     return Answer;
1019 }
1020
1021 #endif /*SQUID_SNMP */