src/neighbors.cc

   1 /*
   2  * Copyright (C) 1996-2018 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 15    Neighbor Routines */
  10
  11 #include "squid.h"
  12 #include "acl/FilledChecklist.h"
  13 #include "anyp/PortCfg.h"
  14 #include "base/EnumIterator.h"
  15 #include "CacheDigest.h"
  16 #include "CachePeer.h"
  17 #include "comm/Connection.h"
  18 #include "comm/ConnOpener.h"
  19 #include "event.h"
  20 #include "FwdState.h"
  21 #include "globals.h"
  22 #include "htcp.h"
  23 #include "HttpRequest.h"
  24 #include "icmp/net_db.h"
  25 #include "ICP.h"
  26 #include "int.h"
  27 #include "ip/Address.h"
  28 #include "ip/tools.h"
  29 #include "ipcache.h"
  30 #include "MemObject.h"
  31 #include "mgr/Registration.h"
  32 #include "multicast.h"
  33 #include "neighbors.h"
  34 #include "NeighborTypeDomainList.h"
  35 #include "pconn.h"
  36 #include "PeerDigest.h"
  37 #include "PeerPoolMgr.h"
  38 #include "PeerSelectState.h"
  39 #include "RequestFlags.h"
  40 #include "SquidConfig.h"
  41 #include "SquidMath.h"
  42 #include "SquidTime.h"
  43 #include "stat.h"
  44 #include "Store.h"
  45 #include "store_key_md5.h"
  46 #include "tools.h"
  47
  48 /* count mcast group peers every 15 minutes */
  49 #define MCAST_COUNT_RATE 900
  50
  51 bool peerAllowedToUse(const CachePeer *, PeerSelector *);
  52 static int peerWouldBePinged(const CachePeer *, PeerSelector *);
  53 static void neighborRemove(CachePeer *);
  54 static void neighborAlive(CachePeer *, const MemObject *, const icp_common_t *);
  55 #if USE_HTCP
  56 static void neighborAliveHtcp(CachePeer *, const MemObject *, const HtcpReplyData *);
  57 #endif
  58 static void neighborCountIgnored(CachePeer *);
  59 static void peerRefreshDNS(void *);
  60 static IPH peerDNSConfigure;
  61 static void peerProbeConnect(CachePeer *, const bool reprobeIfBusy = false);
  62 static CNCB peerProbeConnectDone;
  63 static void peerCountMcastPeersDone(void *data);
  64 static void peerCountMcastPeersStart(void *data);
  65 static void peerCountMcastPeersSchedule(CachePeer * p, time_t when);
  66 static IRCB peerCountHandleIcpReply;
  67
  68 static void neighborIgnoreNonPeer(const Ip::Address &, icp_opcode);
  69 static OBJH neighborDumpPeers;
  70 static OBJH neighborDumpNonPeers;
  71 static void dump_peers(StoreEntry * sentry, CachePeer * peers);
  72
  73 static unsigned short echo_port;
  74
  75 static int NLateReplies = 0;
  76 static CachePeer *first_ping = NULL;
  77
  78 const char *
  79 neighborTypeStr(const CachePeer * p)
  80 {
  81     if (p->type == PEER_NONE)
  82         return "Non-Peer";
  83
  84     if (p->type == PEER_SIBLING)
  85         return "Sibling";
  86
  87     if (p->type == PEER_MULTICAST)
  88         return "Multicast Group";
  89
  90     return "Parent";
  91 }
  92
  93 CachePeer *
  94 whichPeer(const Ip::Address &from)
  95 {
  96     int j;
  97
  98     CachePeer *p = NULL;
  99     debugs(15, 3, "whichPeer: from " << from);
 100
 101     for (p = Config.peers; p; p = p->next) {
 102         for (j = 0; j < p->n_addresses; ++j) {
 103             if (from == p->addresses[j] && from.port() == p->icp.port) {
 104                 return p;
 105             }
 106         }
 107     }
 108
 109     return NULL;
 110 }
 111
 112 peer_t
 113 neighborType(const CachePeer * p, const AnyP::Uri &url)
 114 {
 115
 116     const NeighborTypeDomainList *d = NULL;
 117
 118     for (d = p->typelist; d; d = d->next) {
 119         if (0 == matchDomainName(url.host(), d->domain))
 120             if (d->type != PEER_NONE)
 121                 return d->type;
 122     }
 123 #if PEER_MULTICAST_SIBLINGS
 124     if (p->type == PEER_MULTICAST)
 125         if (p->options.mcast_siblings)
 126             return PEER_SIBLING;
 127 #endif
 128
 129     return p->type;
 130 }
 131
 132 /**
 133  * \return Whether it is appropriate to fetch REQUEST from PEER.
 134  */
 135 bool
 136 peerAllowedToUse(const CachePeer * p, PeerSelector * ps)
 137 {
 138     assert(ps);
 139     HttpRequest *request = ps->request;
 140     assert(request != NULL);
 141
 142     if (neighborType(p, request->url) == PEER_SIBLING) {
 143 #if PEER_MULTICAST_SIBLINGS
 144         if (p->type == PEER_MULTICAST && p->options.mcast_siblings &&
 145                 (request->flags.noCache || request->flags.refresh || request->flags.loopDetected || request->flags.needValidation))
 146             debugs(15, 2, "peerAllowedToUse(" << p->name << ", " << request->url.authority() << ") : multicast-siblings optimization match");
 147 #endif
 148         if (request->flags.noCache)
 149             return false;
 150
 151         if (request->flags.refresh)
 152             return false;
 153
 154         if (request->flags.loopDetected)
 155             return false;
 156
 157         if (request->flags.needValidation)
 158             return false;
 159     }
 160
 161     // CONNECT requests are proxy requests. Not to be forwarded to origin servers.
 162     // Unless the destination port matches, in which case we MAY perform a 'DIRECT' to this CachePeer.
 163     if (p->options.originserver && request->method == Http::METHOD_CONNECT && request->url.port() != p->http_port)
 164         return false;
 165
 166     if (p->access == NULL)
 167         return true;
 168
 169     ACLFilledChecklist checklist(p->access, request, NULL);
 170     checklist.al = ps->al;
 171     checklist.syncAle(request, nullptr);
 172     return checklist.fastCheck().allowed();
 173 }
 174
 175 /* Return TRUE if it is okay to send an ICP request to this CachePeer.   */
 176 static int
 177 peerWouldBePinged(const CachePeer * p, PeerSelector * ps)
 178 {
 179     assert(ps);
 180     HttpRequest *request = ps->request;
 181
 182     if (p->icp.port == 0)
 183         return 0;
 184
 185     if (p->options.no_query)
 186         return 0;
 187
 188     if (p->options.mcast_responder)
 189         return 0;
 190
 191     if (p->n_addresses == 0)
 192         return 0;
 193
 194     if (p->options.background_ping && (squid_curtime - p->stats.last_query < Config.backgroundPingRate))
 195         return 0;
 196
 197     /* the case below seems strange, but can happen if the
 198      * URL host is on the other side of a firewall */
 199     if (p->type == PEER_SIBLING)
 200         if (!request->flags.hierarchical)
 201             return 0;
 202
 203     if (!peerAllowedToUse(p, ps))
 204         return 0;
 205
 206     /* Ping dead peers every timeout interval */
 207     if (squid_curtime - p->stats.last_query > Config.Timeout.deadPeer)
 208         return 1;
 209
 210     if (!neighborUp(p))
 211         return 0;
 212
 213     return 1;
 214 }
 215
 216 bool
 217 peerCanOpenMore(const CachePeer *p)
 218 {
 219     const int effectiveLimit = p->max_conn <= 0 ? Squid_MaxFD : p->max_conn;
 220     const int remaining = effectiveLimit - p->stats.conn_open;
 221     debugs(15, 7, remaining << '=' << effectiveLimit << '-' << p->stats.conn_open);
 222     return remaining > 0;
 223 }
 224
 225 bool
 226 peerHasConnAvailable(const CachePeer *p)
 227 {
 228     // Standby connections can be used without opening new connections.
 229     const int standbys = p->standby.pool ? p->standby.pool->count() : 0;
 230
 231     // XXX: Some idle pconns can be used without opening new connections.
 232     // Complication: Idle pconns cannot be reused for some requests.
 233     const int usableIdles = 0;
 234
 235     const int available = standbys + usableIdles;
 236     debugs(15, 7, available << '=' << standbys << '+' << usableIdles);
 237     return available > 0;
 238 }
 239
 240 void
 241 peerConnClosed(CachePeer *p)
 242 {
 243     --p->stats.conn_open;
 244     if (p->standby.waitingForClose && peerCanOpenMore(p)) {
 245         p->standby.waitingForClose = false;
 246         PeerPoolMgr::Checkpoint(p->standby.mgr, "conn closed");
 247     }
 248 }
 249
 250 /* Return TRUE if it is okay to send an HTTP request to this CachePeer. */
 251 int
 252 peerHTTPOkay(const CachePeer * p, PeerSelector * ps)
 253 {
 254     if (!peerCanOpenMore(p) && !peerHasConnAvailable(p))
 255         return 0;
 256
 257     if (!peerAllowedToUse(p, ps))
 258         return 0;
 259
 260     if (!neighborUp(p))
 261         return 0;
 262
 263     return 1;
 264 }
 265
 266 int
 267 neighborsCount(PeerSelector *ps)
 268 {
 269     CachePeer *p = NULL;
 270     int count = 0;
 271
 272     for (p = Config.peers; p; p = p->next)
 273         if (peerWouldBePinged(p, ps))
 274             ++count;
 275
 276     debugs(15, 3, "neighborsCount: " << count);
 277
 278     return count;
 279 }
 280
 281 CachePeer *
 282 getFirstUpParent(PeerSelector *ps)
 283 {
 284     assert(ps);
 285     HttpRequest *request = ps->request;
 286
 287     CachePeer *p = NULL;
 288
 289     for (p = Config.peers; p; p = p->next) {
 290         if (!neighborUp(p))
 291             continue;
 292
 293         if (neighborType(p, request->url) != PEER_PARENT)
 294             continue;
 295
 296         if (!peerHTTPOkay(p, ps))
 297             continue;
 298
 299         break;
 300     }
 301
 302     debugs(15, 3, "getFirstUpParent: returning " << (p ? p->host : "NULL"));
 303     return p;
 304 }
 305
 306 CachePeer *
 307 getRoundRobinParent(PeerSelector *ps)
 308 {
 309     assert(ps);
 310     HttpRequest *request = ps->request;
 311
 312     CachePeer *p;
 313     CachePeer *q = NULL;
 314
 315     for (p = Config.peers; p; p = p->next) {
 316         if (!p->options.roundrobin)
 317             continue;
 318
 319         if (neighborType(p, request->url) != PEER_PARENT)
 320             continue;
 321
 322         if (!peerHTTPOkay(p, ps))
 323             continue;
 324
 325         if (p->weight == 0)
 326             continue;
 327
 328         if (q) {
 329             if (p->weight == q->weight) {
 330                 if (q->rr_count < p->rr_count)
 331                     continue;
 332             } else if ( ((double) q->rr_count / q->weight) < ((double) p->rr_count / p->weight)) {
 333                 continue;
 334             }
 335         }
 336
 337         q = p;
 338     }
 339
 340     if (q)
 341         ++ q->rr_count;
 342
 343     debugs(15, 3, HERE << "returning " << (q ? q->host : "NULL"));
 344
 345     return q;
 346 }
 347
 348 CachePeer *
 349 getWeightedRoundRobinParent(PeerSelector *ps)
 350 {
 351     assert(ps);
 352     HttpRequest *request = ps->request;
 353
 354     CachePeer *p;
 355     CachePeer *q = NULL;
 356     int weighted_rtt;
 357
 358     for (p = Config.peers; p; p = p->next) {
 359         if (!p->options.weighted_roundrobin)
 360             continue;
 361
 362         if (neighborType(p, request->url) != PEER_PARENT)
 363             continue;
 364
 365         if (!peerHTTPOkay(p, ps))
 366             continue;
 367
 368         if (q && q->rr_count < p->rr_count)
 369             continue;
 370
 371         q = p;
 372     }
 373
 374     if (q && q->rr_count > 1000000)
 375         for (p = Config.peers; p; p = p->next) {
 376             if (!p->options.weighted_roundrobin)
 377                 continue;
 378
 379             if (neighborType(p, request->url) != PEER_PARENT)
 380                 continue;
 381
 382             p->rr_count = 0;
 383         }
 384
 385     if (q) {
 386         weighted_rtt = (q->stats.rtt - q->basetime) / q->weight;
 387
 388         if (weighted_rtt < 1)
 389             weighted_rtt = 1;
 390
 391         q->rr_count += weighted_rtt;
 392
 393         debugs(15, 3, "getWeightedRoundRobinParent: weighted_rtt " << weighted_rtt);
 394     }
 395
 396     debugs(15, 3, "getWeightedRoundRobinParent: returning " << (q ? q->host : "NULL"));
 397     return q;
 398 }
 399
 400 /**
 401  * This gets called every 5 minutes to clear the round-robin counter.
 402  * The exact timing is an arbitrary default, set on estimate timing of a
 403  * large number of requests in a high-performance environment during the
 404  * period. The larger the number of requests between cycled resets the
 405  * more balanced the operations.
 406  *
 407  \param data    unused.
 408  \todo Make the reset timing a selectable parameter in squid.conf
 409  */
 410 static void
 411 peerClearRRLoop(void *data)
 412 {
 413     peerClearRR();
 414     eventAdd("peerClearRR", peerClearRRLoop, data, 5 * 60.0, 0);
 415 }
 416
 417 /**
 418  * This gets called on startup and restart to kick off the CachePeer round-robin
 419  * maintenance event. It ensures that no matter how many times its called
 420  * no more than one event is scheduled.
 421  */
 422 void
 423 peerClearRRStart(void)
 424 {
 425     static bool event_added = false;
 426     if (!event_added) {
 427         peerClearRRLoop(NULL);
 428         event_added=true;
 429     }
 430 }
 431
 432 /**
 433  * Called whenever the round-robin counters need to be reset to a sane state.
 434  * So far those times are:
 435  *  - On startup and reconfigure - to set the counters to sane initial settings.
 436  *  -  When a CachePeer has revived from dead, to prevent the revived CachePeer being
 437  *     flooded with requests which it has 'missed' during the down period.
 438  */
 439 void
 440 peerClearRR()
 441 {
 442     CachePeer *p = NULL;
 443     for (p = Config.peers; p; p = p->next) {
 444         p->rr_count = 1;
 445     }
 446 }
 447
 448 /**
 449  * Perform all actions when a CachePeer is detected revived.
 450  */
 451 void
 452 peerAlive(CachePeer *p)
 453 {
 454     if (p->stats.logged_state == PEER_DEAD && p->tcp_up) {
 455         debugs(15, DBG_IMPORTANT, "Detected REVIVED " << neighborTypeStr(p) << ": " << p->name);
 456         p->stats.logged_state = PEER_ALIVE;
 457         peerClearRR();
 458         if (p->standby.mgr.valid())
 459             PeerPoolMgr::Checkpoint(p->standby.mgr, "revived peer");
 460     }
 461
 462     p->stats.last_reply = squid_curtime;
 463     p->stats.probe_start = 0;
 464 }
 465
 466 CachePeer *
 467 getDefaultParent(PeerSelector *ps)
 468 {
 469     assert(ps);
 470     HttpRequest *request = ps->request;
 471
 472     CachePeer *p = NULL;
 473
 474     for (p = Config.peers; p; p = p->next) {
 475         if (neighborType(p, request->url) != PEER_PARENT)
 476             continue;
 477
 478         if (!p->options.default_parent)
 479             continue;
 480
 481         if (!peerHTTPOkay(p, ps))
 482             continue;
 483
 484         debugs(15, 3, "getDefaultParent: returning " << p->host);
 485
 486         return p;
 487     }
 488
 489     debugs(15, 3, "getDefaultParent: returning NULL");
 490     return NULL;
 491 }
 492
 493 CachePeer *
 494 getNextPeer(CachePeer * p)
 495 {
 496     return p->next;
 497 }
 498
 499 CachePeer *
 500 getFirstPeer(void)
 501 {
 502     return Config.peers;
 503 }
 504
 505 static void
 506 neighborRemove(CachePeer * target)
 507 {
 508     CachePeer *p = NULL;
 509     CachePeer **P = NULL;
 510     p = Config.peers;
 511     P = &Config.peers;
 512
 513     while (p) {
 514         if (target == p)
 515             break;
 516
 517         P = &p->next;
 518
 519         p = p->next;
 520     }
 521
 522     if (p) {
 523         *P = p->next;
 524         p->next = NULL;
 525         delete p;
 526         --Config.npeers;
 527     }
 528
 529     first_ping = Config.peers;
 530 }
 531
 532 static void
 533 neighborsRegisterWithCacheManager()
 534 {
 535     Mgr::RegisterAction("server_list",
 536                         "Peer Cache Statistics",
 537                         neighborDumpPeers, 0, 1);
 538
 539     if (Comm::IsConnOpen(icpIncomingConn)) {
 540         Mgr::RegisterAction("non_peers",
 541                             "List of Unknown sites sending ICP messages",
 542                             neighborDumpNonPeers, 0, 1);
 543     }
 544 }
 545
 546 void
 547 neighbors_init(void)
 548 {
 549     struct servent *sep = NULL;
 550     const char *me = getMyHostname();
 551     CachePeer *thisPeer = NULL;
 552     CachePeer *next = NULL;
 553
 554     neighborsRegisterWithCacheManager();
 555
 556     if (Comm::IsConnOpen(icpIncomingConn)) {
 557
 558         for (thisPeer = Config.peers; thisPeer; thisPeer = next) {
 559             next = thisPeer->next;
 560
 561             if (0 != strcmp(thisPeer->host, me))
 562                 continue;
 563
 564             for (AnyP::PortCfgPointer s = HttpPortList; s != NULL; s = s->next) {
 565                 if (thisPeer->http_port != s->s.port())
 566                     continue;
 567
 568                 debugs(15, DBG_IMPORTANT, "WARNING: Peer looks like this host");
 569
 570                 debugs(15, DBG_IMPORTANT, "         Ignoring " <<
 571                        neighborTypeStr(thisPeer) << " " << thisPeer->host <<
 572                        "/" << thisPeer->http_port << "/" <<
 573                        thisPeer->icp.port);
 574
 575                 neighborRemove(thisPeer);
 576             }
 577         }
 578     }
 579
 580     peerRefreshDNS((void *) 1);
 581
 582     sep = getservbyname("echo", "udp");
 583     echo_port = sep ? ntohs((unsigned short) sep->s_port) : 7;
 584
 585     first_ping = Config.peers;
 586 }
 587
 588 int
 589 neighborsUdpPing(HttpRequest * request,
 590                  StoreEntry * entry,
 591                  IRCB * callback,
 592                  PeerSelector *ps,
 593                  int *exprep,
 594                  int *timeout)
 595 {
 596     const char *url = entry->url();
 597     MemObject *mem = entry->mem_obj;
 598     CachePeer *p = NULL;
 599     int i;
 600     int reqnum = 0;
 601     int flags;
 602     int queries_sent = 0;
 603     int peers_pinged = 0;
 604     int parent_timeout = 0, parent_exprep = 0;
 605     int sibling_timeout = 0, sibling_exprep = 0;
 606     int mcast_timeout = 0, mcast_exprep = 0;
 607
 608     if (Config.peers == NULL)
 609         return 0;
 610
 611     assert(!entry->hasDisk());
 612
 613     mem->start_ping = current_time;
 614
 615     mem->ping_reply_callback = callback;
 616
 617     mem->ircb_data = ps;
 618
 619     reqnum = icpSetCacheKey((const cache_key *)entry->key);
 620
 621     for (i = 0, p = first_ping; i++ < Config.npeers; p = p->next) {
 622         if (p == NULL)
 623             p = Config.peers;
 624
 625         debugs(15, 5, "neighborsUdpPing: Peer " << p->host);
 626
 627         if (!peerWouldBePinged(p, ps))
 628             continue;       /* next CachePeer */
 629
 630         ++peers_pinged;
 631
 632         debugs(15, 4, "neighborsUdpPing: pinging peer " << p->host << " for '" << url << "'");
 633
 634         debugs(15, 3, "neighborsUdpPing: key = '" << entry->getMD5Text() << "'");
 635
 636         debugs(15, 3, "neighborsUdpPing: reqnum = " << reqnum);
 637
 638 #if USE_HTCP
 639         if (p->options.htcp && !p->options.htcp_only_clr) {
 640             if (Config.Port.htcp <= 0) {
 641                 debugs(15, DBG_CRITICAL, "HTCP is disabled! Cannot send HTCP request to peer.");
 642                 continue;
 643             }
 644
 645             debugs(15, 3, "neighborsUdpPing: sending HTCP query");
 646             if (htcpQuery(entry, request, p) <= 0)
 647                 continue; // unable to send.
 648         } else
 649 #endif
 650         {
 651             if (Config.Port.icp <= 0 || !Comm::IsConnOpen(icpOutgoingConn)) {
 652                 debugs(15, DBG_CRITICAL, "ICP is disabled! Cannot send ICP request to peer.");
 653                 continue;
 654             } else {
 655
 656                 if (p->type == PEER_MULTICAST)
 657                     mcastSetTtl(icpOutgoingConn->fd, p->mcast.ttl);
 658
 659                 if (p->icp.port == echo_port) {
 660                     debugs(15, 4, "neighborsUdpPing: Looks like a dumb cache, send DECHO ping");
 661                     // TODO: Get ALE from callback_data if possible.
 662                     icpCreateAndSend(ICP_DECHO, 0, url, reqnum, 0,
 663                                      icpOutgoingConn->fd, p->in_addr, nullptr);
 664                 } else {
 665                     flags = 0;
 666
 667                     if (Config.onoff.query_icmp)
 668                         if (p->icp.version == ICP_VERSION_2)
 669                             flags |= ICP_FLAG_SRC_RTT;
 670
 671                     // TODO: Get ALE from callback_data if possible.
 672                     icpCreateAndSend(ICP_QUERY, flags, url, reqnum, 0,
 673                                      icpOutgoingConn->fd, p->in_addr, nullptr);
 674                 }
 675             }
 676         }
 677
 678         ++queries_sent;
 679
 680         ++ p->stats.pings_sent;
 681
 682         if (p->type == PEER_MULTICAST) {
 683             mcast_exprep += p->mcast.n_replies_expected;
 684             mcast_timeout += (p->stats.rtt * p->mcast.n_replies_expected);
 685         } else if (neighborUp(p)) {
 686             /* its alive, expect a reply from it */
 687
 688             if (neighborType(p, request->url) == PEER_PARENT) {
 689                 ++parent_exprep;
 690                 parent_timeout += p->stats.rtt;
 691             } else {
 692                 ++sibling_exprep;
 693                 sibling_timeout += p->stats.rtt;
 694             }
 695         } else {
 696             /* Neighbor is dead; ping it anyway, but don't expect a reply */
 697             /* log it once at the threshold */
 698
 699             if (p->stats.logged_state == PEER_ALIVE) {
 700                 debugs(15, DBG_IMPORTANT, "Detected DEAD " << neighborTypeStr(p) << ": " << p->name);
 701                 p->stats.logged_state = PEER_DEAD;
 702             }
 703         }
 704
 705         p->stats.last_query = squid_curtime;
 706
 707         /*
 708          * keep probe_start == 0 for a multicast CachePeer,
 709          * so neighborUp() never says this CachePeer is dead.
 710          */
 711
 712         if ((p->type != PEER_MULTICAST) && (p->stats.probe_start == 0))
 713             p->stats.probe_start = squid_curtime;
 714     }
 715
 716     if ((first_ping = first_ping->next) == NULL)
 717         first_ping = Config.peers;
 718
 719     /*
 720      * How many replies to expect?
 721      */
 722     *exprep = parent_exprep + sibling_exprep + mcast_exprep;
 723
 724     /*
 725      * If there is a configured timeout, use it
 726      */
 727     if (Config.Timeout.icp_query)
 728         *timeout = Config.Timeout.icp_query;
 729     else {
 730         if (*exprep > 0) {
 731             if (parent_exprep)
 732                 *timeout = 2 * parent_timeout / parent_exprep;
 733             else if (mcast_exprep)
 734                 *timeout = 2 * mcast_timeout / mcast_exprep;
 735             else
 736                 *timeout = 2 * sibling_timeout / sibling_exprep;
 737         } else
 738             *timeout = 2000;    /* 2 seconds */
 739
 740         if (Config.Timeout.icp_query_max)
 741             if (*timeout > Config.Timeout.icp_query_max)
 742                 *timeout = Config.Timeout.icp_query_max;
 743
 744         if (*timeout < Config.Timeout.icp_query_min)
 745             *timeout = Config.Timeout.icp_query_min;
 746     }
 747
 748     return peers_pinged;
 749 }
 750
 751 /* lookup the digest of a given CachePeer */
 752 lookup_t
 753 peerDigestLookup(CachePeer * p, PeerSelector * ps)
 754 {
 755 #if USE_CACHE_DIGESTS
 756     assert(ps);
 757     HttpRequest *request = ps->request;
 758     const cache_key *key = request ? storeKeyPublicByRequest(request) : NULL;
 759     assert(p);
 760     assert(request);
 761     debugs(15, 5, "peerDigestLookup: peer " << p->host);
 762     /* does the peeer have a valid digest? */
 763
 764     if (!p->digest) {
 765         debugs(15, 5, "peerDigestLookup: gone!");
 766         return LOOKUP_NONE;
 767     } else if (!peerHTTPOkay(p, ps)) {
 768         debugs(15, 5, "peerDigestLookup: !peerHTTPOkay");
 769         return LOOKUP_NONE;
 770     } else if (!p->digest->flags.needed) {
 771         debugs(15, 5, "peerDigestLookup: note need");
 772         peerDigestNeeded(p->digest);
 773         return LOOKUP_NONE;
 774     } else if (!p->digest->flags.usable) {
 775         debugs(15, 5, "peerDigestLookup: !ready && " << (p->digest->flags.requested ? "" : "!") << "requested");
 776         return LOOKUP_NONE;
 777     }
 778
 779     debugs(15, 5, "peerDigestLookup: OK to lookup peer " << p->host);
 780     assert(p->digest->cd);
 781     /* does digest predict a hit? */
 782
 783     if (!p->digest->cd->contains(key))
 784         return LOOKUP_MISS;
 785
 786     debugs(15, 5, "peerDigestLookup: peer " << p->host << " says HIT!");
 787
 788     return LOOKUP_HIT;
 789
 790 #endif
 791
 792     return LOOKUP_NONE;
 793 }
 794
 795 /* select best CachePeer based on cache digests */
 796 CachePeer *
 797 neighborsDigestSelect(PeerSelector *ps)
 798 {
 799     CachePeer *best_p = NULL;
 800 #if USE_CACHE_DIGESTS
 801     assert(ps);
 802     HttpRequest *request = ps->request;
 803
 804     int best_rtt = 0;
 805     int choice_count = 0;
 806     int ichoice_count = 0;
 807     CachePeer *p;
 808     int p_rtt;
 809     int i;
 810
 811     if (!request->flags.hierarchical)
 812         return NULL;
 813
 814     storeKeyPublicByRequest(request);
 815
 816     for (i = 0, p = first_ping; i++ < Config.npeers; p = p->next) {
 817         lookup_t lookup;
 818
 819         if (!p)
 820             p = Config.peers;
 821
 822         if (i == 1)
 823             first_ping = p;
 824
 825         lookup = peerDigestLookup(p, ps);
 826
 827         if (lookup == LOOKUP_NONE)
 828             continue;
 829
 830         ++choice_count;
 831
 832         if (lookup == LOOKUP_MISS)
 833             continue;
 834
 835         p_rtt = netdbHostRtt(p->host);
 836
 837         debugs(15, 5, "neighborsDigestSelect: peer " << p->host << " rtt: " << p_rtt);
 838
 839         /* is this CachePeer better than others in terms of rtt ? */
 840         if (!best_p || (p_rtt && p_rtt < best_rtt)) {
 841             best_p = p;
 842             best_rtt = p_rtt;
 843
 844             if (p_rtt)      /* informative choice (aka educated guess) */
 845                 ++ichoice_count;
 846
 847             debugs(15, 4, "neighborsDigestSelect: peer " << p->host << " leads with rtt " << best_rtt);
 848         }
 849     }
 850
 851     debugs(15, 4, "neighborsDigestSelect: choices: " << choice_count << " (" << ichoice_count << ")");
 852     peerNoteDigestLookup(request, best_p,
 853                          best_p ? LOOKUP_HIT : (choice_count ? LOOKUP_MISS : LOOKUP_NONE));
 854     request->hier.n_choices = choice_count;
 855     request->hier.n_ichoices = ichoice_count;
 856 #endif
 857
 858     return best_p;
 859 }
 860
 861 void
 862 peerNoteDigestLookup(HttpRequest * request, CachePeer * p, lookup_t lookup)
 863 {
 864 #if USE_CACHE_DIGESTS
 865     if (p)
 866         strncpy(request->hier.cd_host, p->host, sizeof(request->hier.cd_host)-1);
 867     else
 868         *request->hier.cd_host = '\0';
 869
 870     request->hier.cd_lookup = lookup;
 871     debugs(15, 4, "peerNoteDigestLookup: peer " << (p? p->host : "<none>") << ", lookup: " << lookup_t_str[lookup]  );
 872 #endif
 873 }
 874
 875 static void
 876 neighborAlive(CachePeer * p, const MemObject *, const icp_common_t * header)
 877 {
 878     peerAlive(p);
 879     ++ p->stats.pings_acked;
 880
 881     if ((icp_opcode) header->opcode <= ICP_END)
 882         ++ p->icp.counts[header->opcode];
 883
 884     p->icp.version = (int) header->version;
 885 }
 886
 887 static void
 888 neighborUpdateRtt(CachePeer * p, MemObject * mem)
 889 {
 890     int rtt, rtt_av_factor;
 891
 892     if (!mem)
 893         return;
 894
 895     if (!mem->start_ping.tv_sec)
 896         return;
 897
 898     rtt = tvSubMsec(mem->start_ping, current_time);
 899
 900     if (rtt < 1 || rtt > 10000)
 901         return;
 902
 903     rtt_av_factor = RTT_AV_FACTOR;
 904
 905     if (p->options.weighted_roundrobin)
 906         rtt_av_factor = RTT_BACKGROUND_AV_FACTOR;
 907
 908     p->stats.rtt = Math::intAverage(p->stats.rtt, rtt, p->stats.pings_acked, rtt_av_factor);
 909 }
 910
 911 #if USE_HTCP
 912 static void
 913 neighborAliveHtcp(CachePeer * p, const MemObject *, const HtcpReplyData * htcp)
 914 {
 915     peerAlive(p);
 916     ++ p->stats.pings_acked;
 917     ++ p->htcp.counts[htcp->hit ? 1 : 0];
 918     p->htcp.version = htcp->version;
 919 }
 920
 921 #endif
 922
 923 static void
 924 neighborCountIgnored(CachePeer * p)
 925 {
 926     if (p == NULL)
 927         return;
 928
 929     ++ p->stats.ignored_replies;
 930
 931     ++NLateReplies;
 932 }
 933
 934 static CachePeer *non_peers = NULL;
 935
 936 static void
 937 neighborIgnoreNonPeer(const Ip::Address &from, icp_opcode opcode)
 938 {
 939     CachePeer *np;
 940
 941     for (np = non_peers; np; np = np->next) {
 942         if (np->in_addr != from)
 943             continue;
 944
 945         if (np->in_addr.port() != from.port())
 946             continue;
 947
 948         break;
 949     }
 950
 951     if (np == NULL) {
 952         np = new CachePeer;
 953         np->in_addr = from;
 954         np->icp.port = from.port();
 955         np->type = PEER_NONE;
 956         np->host = new char[MAX_IPSTRLEN];
 957         from.toStr(np->host,MAX_IPSTRLEN);
 958         np->next = non_peers;
 959         non_peers = np;
 960     }
 961
 962     ++ np->icp.counts[opcode];
 963
 964     if (isPowTen(++np->stats.ignored_replies))
 965         debugs(15, DBG_IMPORTANT, "WARNING: Ignored " << np->stats.ignored_replies << " replies from non-peer " << np->host);
 966 }
 967
 968 /* ignoreMulticastReply
 969  *
 970  * * We want to ignore replies from multicast peers if the
 971  * * cache_host_domain rules would normally prevent the CachePeer
 972  * * from being used
 973  */
 974 static int
 975 ignoreMulticastReply(CachePeer * p, PeerSelector * ps)
 976 {
 977     if (p == NULL)
 978         return 0;
 979
 980     if (!p->options.mcast_responder)
 981         return 0;
 982
 983     if (peerHTTPOkay(p, ps))
 984         return 0;
 985
 986     return 1;
 987 }
 988
 989 /**
 990  * I should attach these records to the entry.  We take the first
 991  * hit we get our wait until everyone misses.  The timeout handler
 992  * call needs to nip this shopping list or call one of the misses.
 993  *
 994  * If a hit process is already started, then sobeit
 995  */
 996 void
 997 neighborsUdpAck(const cache_key * key, icp_common_t * header, const Ip::Address &from)
 998 {
 999     CachePeer *p = NULL;
1000     StoreEntry *entry;
1001     MemObject *mem = NULL;
1002     peer_t ntype = PEER_NONE;
1003     icp_opcode opcode = (icp_opcode) header->opcode;
1004
1005     debugs(15, 6, "neighborsUdpAck: opcode " << opcode << " '" << storeKeyText(key) << "'");
1006
1007     if ((entry = Store::Root().findCallbackXXX(key)))
1008         mem = entry->mem_obj;
1009
1010     if ((p = whichPeer(from)))
1011         neighborAlive(p, mem, header);
1012
1013     if (opcode > ICP_END)
1014         return;
1015
1016     const char *opcode_d = icp_opcode_str[opcode];
1017
1018     if (p)
1019         neighborUpdateRtt(p, mem);
1020
1021     /* Does the entry exist? */
1022     if (NULL == entry) {
1023         debugs(12, 3, "neighborsUdpAck: Cache key '" << storeKeyText(key) << "' not found");
1024         neighborCountIgnored(p);
1025         return;
1026     }
1027
1028     /* check if someone is already fetching it */
1029     if (EBIT_TEST(entry->flags, ENTRY_DISPATCHED)) {
1030         debugs(15, 3, "neighborsUdpAck: '" << storeKeyText(key) << "' already being fetched.");
1031         neighborCountIgnored(p);
1032         return;
1033     }
1034
1035     if (mem == NULL) {
1036         debugs(15, 2, "Ignoring " << opcode_d << " for missing mem_obj: " << storeKeyText(key));
1037         neighborCountIgnored(p);
1038         return;
1039     }
1040
1041     if (entry->ping_status != PING_WAITING) {
1042         debugs(15, 2, "neighborsUdpAck: Late " << opcode_d << " for " << storeKeyText(key));
1043         neighborCountIgnored(p);
1044         return;
1045     }
1046
1047     if (!entry->locked()) {
1048         // TODO: many entries are unlocked; why is this reported at level 1?
1049         debugs(12, DBG_IMPORTANT, "neighborsUdpAck: '" << storeKeyText(key) << "' has no locks");
1050         neighborCountIgnored(p);
1051         return;
1052     }
1053
1054     if (!mem->ircb_data) {
1055         debugs(12, DBG_IMPORTANT, "BUG: missing ICP callback data for " << *entry);
1056         neighborCountIgnored(p);
1057         return;
1058     }
1059
1060     debugs(15, 3, "neighborsUdpAck: " << opcode_d << " for '" << storeKeyText(key) << "' from " << (p ? p->host : "source") << " ");
1061
1062     if (p) {
1063         ntype = neighborType(p, mem->request->url);
1064     }
1065
1066     if (ignoreMulticastReply(p, mem->ircb_data)) {
1067         neighborCountIgnored(p);
1068     } else if (opcode == ICP_MISS) {
1069         if (p == NULL) {
1070             neighborIgnoreNonPeer(from, opcode);
1071         } else {
1072             mem->ping_reply_callback(p, ntype, AnyP::PROTO_ICP, header, mem->ircb_data);
1073         }
1074     } else if (opcode == ICP_HIT) {
1075         if (p == NULL) {
1076             neighborIgnoreNonPeer(from, opcode);
1077         } else {
1078             header->opcode = ICP_HIT;
1079             mem->ping_reply_callback(p, ntype, AnyP::PROTO_ICP, header, mem->ircb_data);
1080         }
1081     } else if (opcode == ICP_DECHO) {
1082         if (p == NULL) {
1083             neighborIgnoreNonPeer(from, opcode);
1084         } else if (ntype == PEER_SIBLING) {
1085             debug_trap("neighborsUdpAck: Found non-ICP cache as SIBLING\n");
1086             debug_trap("neighborsUdpAck: non-ICP neighbors must be a PARENT\n");
1087         } else {
1088             mem->ping_reply_callback(p, ntype, AnyP::PROTO_ICP, header, mem->ircb_data);
1089         }
1090     } else if (opcode == ICP_SECHO) {
1091         if (p) {
1092             debugs(15, DBG_IMPORTANT, "Ignoring SECHO from neighbor " << p->host);
1093             neighborCountIgnored(p);
1094         } else {
1095             debugs(15, DBG_IMPORTANT, "Unsolicited SECHO from " << from);
1096         }
1097     } else if (opcode == ICP_DENIED) {
1098         if (p == NULL) {
1099             neighborIgnoreNonPeer(from, opcode);
1100         } else if (p->stats.pings_acked > 100) {
1101             if (100 * p->icp.counts[ICP_DENIED] / p->stats.pings_acked > 95) {
1102                 debugs(15, DBG_CRITICAL, "95%% of replies from '" << p->host << "' are UDP_DENIED");
1103                 debugs(15, DBG_CRITICAL, "Disabling '" << p->host << "', please check your configuration.");
1104                 neighborRemove(p);
1105                 p = NULL;
1106             } else {
1107                 neighborCountIgnored(p);
1108             }
1109         }
1110     } else if (opcode == ICP_MISS_NOFETCH) {
1111         mem->ping_reply_callback(p, ntype, AnyP::PROTO_ICP, header, mem->ircb_data);
1112     } else {
1113         debugs(15, DBG_CRITICAL, "neighborsUdpAck: Unexpected ICP reply: " << opcode_d);
1114     }
1115 }
1116
1117 CachePeer *
1118 peerFindByName(const char *name)
1119 {
1120     CachePeer *p = NULL;
1121
1122     for (p = Config.peers; p; p = p->next) {
1123         if (!strcasecmp(name, p->name))
1124             break;
1125     }
1126
1127     return p;
1128 }
1129
1130 CachePeer *
1131 peerFindByNameAndPort(const char *name, unsigned short port)
1132 {
1133     CachePeer *p = NULL;
1134
1135     for (p = Config.peers; p; p = p->next) {
1136         if (strcasecmp(name, p->name))
1137             continue;
1138
1139         if (port != p->http_port)
1140             continue;
1141
1142         break;
1143     }
1144
1145     return p;
1146 }
1147
1148 int
1149 neighborUp(const CachePeer * p)
1150 {
1151     if (!p->tcp_up) {
1152         peerProbeConnect(const_cast<CachePeer*>(p));
1153         return 0;
1154     }
1155
1156     /*
1157      * The CachePeer can not be UP if we don't have any IP addresses
1158      * for it.
1159      */
1160     if (0 == p->n_addresses) {
1161         debugs(15, 8, "neighborUp: DOWN (no-ip): " << p->host << " (" << p->in_addr << ")");
1162         return 0;
1163     }
1164
1165     if (p->options.no_query) {
1166         debugs(15, 8, "neighborUp: UP (no-query): " << p->host << " (" << p->in_addr << ")");
1167         return 1;
1168     }
1169
1170     if (p->stats.probe_start != 0 &&
1171             squid_curtime - p->stats.probe_start > Config.Timeout.deadPeer) {
1172         debugs(15, 8, "neighborUp: DOWN (dead): " << p->host << " (" << p->in_addr << ")");
1173         return 0;
1174     }
1175
1176     debugs(15, 8, "neighborUp: UP: " << p->host << " (" << p->in_addr << ")");
1177     return 1;
1178 }
1179
1180 void
1181 peerNoteDigestGone(CachePeer * p)
1182 {
1183 #if USE_CACHE_DIGESTS
1184     cbdataReferenceDone(p->digest);
1185 #endif
1186 }
1187
1188 /// \returns the effective connect timeout for this peer
1189 time_t
1190 peerConnectTimeout(const CachePeer *peer)
1191 {
1192     return peer->connect_timeout_raw > 0 ?
1193            peer->connect_timeout_raw : Config.Timeout.peer_connect;
1194 }
1195
1196 time_t
1197 positiveTimeout(const time_t timeout)
1198 {
1199     return max(static_cast<time_t>(1), timeout);
1200 }
1201
1202 static void
1203 peerDNSConfigure(const ipcache_addrs *ia, const Dns::LookupDetails &, void *data)
1204 {
1205     // TODO: connections to no-longer valid IP addresses should be
1206     // closed when we can detect such IP addresses.
1207
1208     CachePeer *p = (CachePeer *)data;
1209
1210     if (p->n_addresses == 0) {
1211         debugs(15, DBG_IMPORTANT, "Configuring " << neighborTypeStr(p) << " " << p->host << "/" << p->http_port << "/" << p->icp.port);
1212
1213         if (p->type == PEER_MULTICAST)
1214             debugs(15, DBG_IMPORTANT, "    Multicast TTL = " << p->mcast.ttl);
1215     }
1216
1217     p->n_addresses = 0;
1218
1219     if (ia == NULL) {
1220         debugs(0, DBG_CRITICAL, "WARNING: DNS lookup for '" << p->host << "' failed!");
1221         return;
1222     }
1223
1224     if (ia->empty()) {
1225         debugs(0, DBG_CRITICAL, "WARNING: No IP address found for '" << p->host << "'!");
1226         return;
1227     }
1228
1229     for (const auto &ip: ia->goodAndBad()) { // TODO: Consider using just good().
1230         if (p->n_addresses < PEER_MAX_ADDRESSES) {
1231             const auto idx = p->n_addresses++;
1232             p->addresses[idx] = ip;
1233             debugs(15, 2, "--> IP address #" << idx << ": " << p->addresses[idx]);
1234         } else {
1235             debugs(15, 3, "ignoring remaining " << (ia->size() - p->n_addresses) << " ips");
1236             break;
1237         }
1238     }
1239
1240     p->in_addr.setEmpty();
1241     p->in_addr = p->addresses[0];
1242     p->in_addr.port(p->icp.port);
1243
1244     peerProbeConnect(p, true); // detect any died or revived peers ASAP
1245
1246     if (p->type == PEER_MULTICAST)
1247         peerCountMcastPeersSchedule(p, 10);
1248
1249 #if USE_ICMP
1250     if (p->type != PEER_MULTICAST && IamWorkerProcess())
1251         if (!p->options.no_netdb_exchange)
1252             eventAddIsh("netdbExchangeStart", netdbExchangeStart, p, 30.0, 1);
1253 #endif
1254
1255     if (p->standby.mgr.valid())
1256         PeerPoolMgr::Checkpoint(p->standby.mgr, "resolved peer");
1257 }
1258
1259 static void
1260 peerRefreshDNS(void *data)
1261 {
1262     CachePeer *p = NULL;
1263
1264     if (eventFind(peerRefreshDNS, NULL))
1265         eventDelete(peerRefreshDNS, NULL);
1266
1267     if (!data && 0 == stat5minClientRequests()) {
1268         /* no recent client traffic, wait a bit */
1269         eventAddIsh("peerRefreshDNS", peerRefreshDNS, NULL, 180.0, 1);
1270         return;
1271     }
1272
1273     for (p = Config.peers; p; p = p->next)
1274         ipcache_nbgethostbyname(p->host, peerDNSConfigure, p);
1275
1276     /* Reconfigure the peers every hour */
1277     eventAddIsh("peerRefreshDNS", peerRefreshDNS, NULL, 3600.0, 1);
1278 }
1279
1280 static void
1281 peerConnectFailedSilent(CachePeer * p)
1282 {
1283     p->stats.last_connect_failure = squid_curtime;
1284
1285     if (!p->tcp_up) {
1286         debugs(15, 2, "TCP connection to " << p->host << "/" << p->http_port <<
1287                " dead");
1288         return;
1289     }
1290
1291     -- p->tcp_up;
1292
1293     if (!p->tcp_up) {
1294         debugs(15, DBG_IMPORTANT, "Detected DEAD " << neighborTypeStr(p) << ": " << p->name);
1295         p->stats.logged_state = PEER_DEAD;
1296     }
1297 }
1298
1299 void
1300 peerConnectFailed(CachePeer *p)
1301 {
1302     debugs(15, DBG_IMPORTANT, "TCP connection to " << p->host << "/" << p->http_port << " failed");
1303     peerConnectFailedSilent(p);
1304 }
1305
1306 void
1307 peerConnectSucceded(CachePeer * p)
1308 {
1309     if (!p->tcp_up) {
1310         debugs(15, 2, "TCP connection to " << p->host << "/" << p->http_port << " succeeded");
1311         p->tcp_up = p->connect_fail_limit; // NP: so peerAlive(p) works properly.
1312         peerAlive(p);
1313         if (!p->n_addresses)
1314             ipcache_nbgethostbyname(p->host, peerDNSConfigure, p);
1315     } else
1316         p->tcp_up = p->connect_fail_limit;
1317 }
1318
1319 /// whether new TCP probes are currently banned
1320 static bool
1321 peerProbeIsBusy(const CachePeer *p)
1322 {
1323     if (p->testing_now > 0) {
1324         debugs(15, 8, "yes, probing " << p);
1325         return true;
1326     }
1327     if (squid_curtime - p->stats.last_connect_probe == 0) {
1328         debugs(15, 8, "yes, just probed " << p);
1329         return true;
1330     }
1331     return false;
1332 }
1333 /*
1334 * peerProbeConnect will be called on dead peers by neighborUp
1335 */
1336 static void
1337 peerProbeConnect(CachePeer *p, const bool reprobeIfBusy)
1338 {
1339     if (peerProbeIsBusy(p)) {
1340         p->reprobe = reprobeIfBusy;
1341         return;
1342     }
1343     p->reprobe = false;
1344
1345     const time_t ctimeout = peerConnectTimeout(p);
1346     /* for each IP address of this CachePeer. find one that we can connect to and probe it. */
1347     for (int i = 0; i < p->n_addresses; ++i) {
1348         Comm::ConnectionPointer conn = new Comm::Connection;
1349         conn->remote = p->addresses[i];
1350         conn->remote.port(p->http_port);
1351         conn->setPeer(p);
1352         getOutgoingAddress(NULL, conn);
1353
1354         ++ p->testing_now;
1355
1356         AsyncCall::Pointer call = commCbCall(15,3, "peerProbeConnectDone", CommConnectCbPtrFun(peerProbeConnectDone, p));
1357         Comm::ConnOpener *cs = new Comm::ConnOpener(conn, call, ctimeout);
1358         cs->setHost(p->host);
1359         AsyncJob::Start(cs);
1360     }
1361
1362     p->stats.last_connect_probe = squid_curtime;
1363 }
1364
1365 static void
1366 peerProbeConnectDone(const Comm::ConnectionPointer &conn, Comm::Flag status, int, void *data)
1367 {
1368     CachePeer *p = (CachePeer*)data;
1369
1370     if (status == Comm::OK) {
1371         peerConnectSucceded(p);
1372     } else {
1373         peerConnectFailedSilent(p);
1374     }
1375
1376     -- p->testing_now;
1377     conn->close();
1378     // TODO: log this traffic.
1379
1380     if (p->reprobe)
1381         peerProbeConnect(p);
1382 }
1383
1384 static void
1385 peerCountMcastPeersSchedule(CachePeer * p, time_t when)
1386 {
1387     if (p->mcast.flags.count_event_pending)
1388         return;
1389
1390     eventAdd("peerCountMcastPeersStart",
1391              peerCountMcastPeersStart,
1392              p,
1393              (double) when, 1);
1394
1395     p->mcast.flags.count_event_pending = true;
1396 }
1397
1398 static void
1399 peerCountMcastPeersStart(void *data)
1400 {
1401     // XXX: Do not create lots of complex fake objects (while abusing their
1402     // APIs) to pass around a few basic data points like start_ping and ping!
1403     CachePeer *p = (CachePeer *)data;
1404     MemObject *mem;
1405     int reqnum;
1406     // TODO: use class AnyP::Uri instead of constructing and re-parsing a string
1407     LOCAL_ARRAY(char, url, MAX_URL);
1408     assert(p->type == PEER_MULTICAST);
1409     p->mcast.flags.count_event_pending = false;
1410     snprintf(url, MAX_URL, "http://");
1411     p->in_addr.toUrl(url+7, MAX_URL -8 );
1412     strcat(url, "/");
1413     const MasterXaction::Pointer mx = new MasterXaction(XactionInitiator::initPeerMcast);
1414     HttpRequest *req = HttpRequest::FromUrl(url, mx);
1415     assert(req != nullptr);
1416     StoreEntry *fake = storeCreateEntry(url, url, RequestFlags(), Http::METHOD_GET);
1417     const auto psstate = new PeerSelector(nullptr);
1418     psstate->request = req;
1419     HTTPMSGLOCK(psstate->request);
1420     psstate->entry = fake;
1421     psstate->peerCountMcastPeerXXX = cbdataReference(p);
1422     psstate->ping.start = current_time;
1423     mem = fake->mem_obj;
1424     mem->request = psstate->request;
1425     mem->start_ping = current_time;
1426     mem->ping_reply_callback = peerCountHandleIcpReply;
1427     mem->ircb_data = psstate;
1428     mcastSetTtl(icpOutgoingConn->fd, p->mcast.ttl);
1429     p->mcast.id = mem->id;
1430     reqnum = icpSetCacheKey((const cache_key *)fake->key);
1431     icpCreateAndSend(ICP_QUERY, 0, url, reqnum, 0,
1432                      icpOutgoingConn->fd, p->in_addr, psstate->al);
1433     fake->ping_status = PING_WAITING;
1434     eventAdd("peerCountMcastPeersDone",
1435              peerCountMcastPeersDone,
1436              psstate,
1437              Config.Timeout.mcast_icp_query / 1000.0, 1);
1438     p->mcast.flags.counting = true;
1439     peerCountMcastPeersSchedule(p, MCAST_COUNT_RATE);
1440 }
1441
1442 static void
1443 peerCountMcastPeersDone(void *data)
1444 {
1445     const auto psstate = static_cast<PeerSelector*>(data);
1446     StoreEntry *fake = psstate->entry;
1447
1448     if (cbdataReferenceValid(psstate->peerCountMcastPeerXXX)) {
1449         CachePeer *p = (CachePeer *)psstate->peerCountMcastPeerXXX;
1450         p->mcast.flags.counting = false;
1451         p->mcast.avg_n_members = Math::doubleAverage(p->mcast.avg_n_members, (double) psstate->ping.n_recv, ++p->mcast.n_times_counted, 10);
1452         debugs(15, DBG_IMPORTANT, "Group " << p->host  << ": " << psstate->ping.n_recv  <<
1453                " replies, "<< std::setw(4)<< std::setprecision(2) <<
1454                p->mcast.avg_n_members <<" average, RTT " << p->stats.rtt);
1455         p->mcast.n_replies_expected = (int) p->mcast.avg_n_members;
1456     }
1457
1458     cbdataReferenceDone(psstate->peerCountMcastPeerXXX);
1459
1460     fake->abort(); // sets ENTRY_ABORTED and initiates releated cleanup
1461     fake->mem_obj->request = nullptr;
1462     fake->unlock("peerCountMcastPeersDone");
1463     delete psstate;
1464 }
1465
1466 static void
1467 peerCountHandleIcpReply(CachePeer * p, peer_t, AnyP::ProtocolType proto, void *, void *data)
1468 {
1469     const auto psstate = static_cast<PeerSelector*>(data);
1470     StoreEntry *fake = psstate->entry;
1471     assert(fake);
1472     MemObject *mem = fake->mem_obj;
1473     assert(mem);
1474     int rtt = tvSubMsec(mem->start_ping, current_time);
1475     assert(proto == AnyP::PROTO_ICP);
1476     ++ psstate->ping.n_recv;
1477     int rtt_av_factor = RTT_AV_FACTOR;
1478
1479     if (p->options.weighted_roundrobin)
1480         rtt_av_factor = RTT_BACKGROUND_AV_FACTOR;
1481
1482     p->stats.rtt = Math::intAverage(p->stats.rtt, rtt, psstate->ping.n_recv, rtt_av_factor);
1483 }
1484
1485 static void
1486 neighborDumpPeers(StoreEntry * sentry)
1487 {
1488     dump_peers(sentry, Config.peers);
1489 }
1490
1491 static void
1492 neighborDumpNonPeers(StoreEntry * sentry)
1493 {
1494     dump_peers(sentry, non_peers);
1495 }
1496
1497 void
1498 dump_peer_options(StoreEntry * sentry, CachePeer * p)
1499 {
1500     if (p->options.proxy_only)
1501         storeAppendPrintf(sentry, " proxy-only");
1502
1503     if (p->options.no_query)
1504         storeAppendPrintf(sentry, " no-query");
1505
1506     if (p->options.background_ping)
1507         storeAppendPrintf(sentry, " background-ping");
1508
1509     if (p->options.no_digest)
1510         storeAppendPrintf(sentry, " no-digest");
1511
1512     if (p->options.default_parent)
1513         storeAppendPrintf(sentry, " default");
1514
1515     if (p->options.roundrobin)
1516         storeAppendPrintf(sentry, " round-robin");
1517
1518     if (p->options.carp)
1519         storeAppendPrintf(sentry, " carp");
1520
1521 #if USE_AUTH
1522     if (p->options.userhash)
1523         storeAppendPrintf(sentry, " userhash");
1524 #endif
1525
1526     if (p->options.sourcehash)
1527         storeAppendPrintf(sentry, " sourcehash");
1528
1529     if (p->options.weighted_roundrobin)
1530         storeAppendPrintf(sentry, " weighted-round-robin");
1531
1532     if (p->options.mcast_responder)
1533         storeAppendPrintf(sentry, " multicast-responder");
1534
1535 #if PEER_MULTICAST_SIBLINGS
1536     if (p->options.mcast_siblings)
1537         storeAppendPrintf(sentry, " multicast-siblings");
1538 #endif
1539
1540     if (p->weight != 1)
1541         storeAppendPrintf(sentry, " weight=%d", p->weight);
1542
1543     if (p->options.closest_only)
1544         storeAppendPrintf(sentry, " closest-only");
1545
1546 #if USE_HTCP
1547     if (p->options.htcp) {
1548         storeAppendPrintf(sentry, " htcp");
1549         if (p->options.htcp_oldsquid || p->options.htcp_no_clr || p->options.htcp_no_purge_clr || p->options.htcp_only_clr) {
1550             bool doneopts = false;
1551             if (p->options.htcp_oldsquid) {
1552                 storeAppendPrintf(sentry, "oldsquid");
1553                 doneopts = true;
1554             }
1555             if (p->options.htcp_no_clr) {
1556                 storeAppendPrintf(sentry, "%sno-clr",(doneopts?",":"="));
1557                 doneopts = true;
1558             }
1559             if (p->options.htcp_no_purge_clr) {
1560                 storeAppendPrintf(sentry, "%sno-purge-clr",(doneopts?",":"="));
1561                 doneopts = true;
1562             }
1563             if (p->options.htcp_only_clr) {
1564                 storeAppendPrintf(sentry, "%sonly-clr",(doneopts?",":"="));
1565                 //doneopts = true; // uncomment if more opts are added
1566             }
1567         }
1568     }
1569 #endif
1570
1571     if (p->options.no_netdb_exchange)
1572         storeAppendPrintf(sentry, " no-netdb-exchange");
1573
1574 #if USE_DELAY_POOLS
1575     if (p->options.no_delay)
1576         storeAppendPrintf(sentry, " no-delay");
1577 #endif
1578
1579     if (p->login)
1580         storeAppendPrintf(sentry, " login=%s", p->login);
1581
1582     if (p->mcast.ttl > 0)
1583         storeAppendPrintf(sentry, " ttl=%d", p->mcast.ttl);
1584
1585     if (p->connect_timeout_raw > 0)
1586         storeAppendPrintf(sentry, " connect-timeout=%d", (int)p->connect_timeout_raw);
1587
1588     if (p->connect_fail_limit != PEER_TCP_MAGIC_COUNT)
1589         storeAppendPrintf(sentry, " connect-fail-limit=%d", p->connect_fail_limit);
1590
1591 #if USE_CACHE_DIGESTS
1592
1593     if (p->digest_url)
1594         storeAppendPrintf(sentry, " digest-url=%s", p->digest_url);
1595
1596 #endif
1597
1598     if (p->options.allow_miss)
1599         storeAppendPrintf(sentry, " allow-miss");
1600
1601     if (p->options.no_tproxy)
1602         storeAppendPrintf(sentry, " no-tproxy");
1603
1604     if (p->max_conn > 0)
1605         storeAppendPrintf(sentry, " max-conn=%d", p->max_conn);
1606     if (p->standby.limit > 0)
1607         storeAppendPrintf(sentry, " standby=%d", p->standby.limit);
1608
1609     if (p->options.originserver)
1610         storeAppendPrintf(sentry, " originserver");
1611
1612     if (p->domain)
1613         storeAppendPrintf(sentry, " forceddomain=%s", p->domain);
1614
1615     if (p->connection_auth == 0)
1616         storeAppendPrintf(sentry, " connection-auth=off");
1617     else if (p->connection_auth == 1)
1618         storeAppendPrintf(sentry, " connection-auth=on");
1619     else if (p->connection_auth == 2)
1620         storeAppendPrintf(sentry, " connection-auth=auto");
1621
1622     p->secure.dumpCfg(sentry,"tls-");
1623     storeAppendPrintf(sentry, "\n");
1624 }
1625
1626 static void
1627 dump_peers(StoreEntry * sentry, CachePeer * peers)
1628 {
1629     char ntoabuf[MAX_IPSTRLEN];
1630     int i;
1631
1632     if (peers == NULL)
1633         storeAppendPrintf(sentry, "There are no neighbors installed.\n");
1634
1635     for (CachePeer *e = peers; e; e = e->next) {
1636         assert(e->host != NULL);
1637         storeAppendPrintf(sentry, "\n%-11.11s: %s\n",
1638                           neighborTypeStr(e),
1639                           e->name);
1640         storeAppendPrintf(sentry, "Host       : %s/%d/%d\n",
1641                           e->host,
1642                           e->http_port,
1643                           e->icp.port);
1644         storeAppendPrintf(sentry, "Flags      :");
1645         dump_peer_options(sentry, e);
1646
1647         for (i = 0; i < e->n_addresses; ++i) {
1648             storeAppendPrintf(sentry, "Address[%d] : %s\n", i,
1649                               e->addresses[i].toStr(ntoabuf,MAX_IPSTRLEN) );
1650         }
1651
1652         storeAppendPrintf(sentry, "Status     : %s\n",
1653                           neighborUp(e) ? "Up" : "Down");
1654         storeAppendPrintf(sentry, "FETCHES    : %d\n", e->stats.fetches);
1655         storeAppendPrintf(sentry, "OPEN CONNS : %d\n", e->stats.conn_open);
1656         storeAppendPrintf(sentry, "AVG RTT    : %d msec\n", e->stats.rtt);
1657
1658         if (!e->options.no_query) {
1659             storeAppendPrintf(sentry, "LAST QUERY : %8d seconds ago\n",
1660                               (int) (squid_curtime - e->stats.last_query));
1661
1662             if (e->stats.last_reply > 0)
1663                 storeAppendPrintf(sentry, "LAST REPLY : %8d seconds ago\n",
1664                                   (int) (squid_curtime - e->stats.last_reply));
1665             else
1666                 storeAppendPrintf(sentry, "LAST REPLY : none received\n");
1667
1668             storeAppendPrintf(sentry, "PINGS SENT : %8d\n", e->stats.pings_sent);
1669
1670             storeAppendPrintf(sentry, "PINGS ACKED: %8d %3d%%\n",
1671                               e->stats.pings_acked,
1672                               Math::intPercent(e->stats.pings_acked, e->stats.pings_sent));
1673         }
1674
1675         storeAppendPrintf(sentry, "IGNORED    : %8d %3d%%\n", e->stats.ignored_replies, Math::intPercent(e->stats.ignored_replies, e->stats.pings_acked));
1676
1677         if (!e->options.no_query) {
1678             storeAppendPrintf(sentry, "Histogram of PINGS ACKED:\n");
1679 #if USE_HTCP
1680
1681             if (e->options.htcp) {
1682                 storeAppendPrintf(sentry, "\tMisses\t%8d %3d%%\n",
1683                                   e->htcp.counts[0],
1684                                   Math::intPercent(e->htcp.counts[0], e->stats.pings_acked));
1685                 storeAppendPrintf(sentry, "\tHits\t%8d %3d%%\n",
1686                                   e->htcp.counts[1],
1687                                   Math::intPercent(e->htcp.counts[1], e->stats.pings_acked));
1688             } else {
1689 #endif
1690
1691                 for (auto op : WholeEnum<icp_opcode>()) {
1692                     if (e->icp.counts[op] == 0)
1693                         continue;
1694
1695                     storeAppendPrintf(sentry, "    %12.12s : %8d %3d%%\n",
1696                                       icp_opcode_str[op],
1697                                       e->icp.counts[op],
1698                                       Math::intPercent(e->icp.counts[op], e->stats.pings_acked));
1699                 }
1700
1701 #if USE_HTCP
1702
1703             }
1704
1705 #endif
1706
1707         }
1708
1709         if (e->stats.last_connect_failure) {
1710             storeAppendPrintf(sentry, "Last failed connect() at: %s\n",
1711                               Time::FormatHttpd(e->stats.last_connect_failure));
1712         }
1713
1714         storeAppendPrintf(sentry, "keep-alive ratio: %d%%\n", Math::intPercent(e->stats.n_keepalives_recv, e->stats.n_keepalives_sent));
1715     }
1716 }
1717
1718 #if USE_HTCP
1719 void
1720 neighborsHtcpReply(const cache_key * key, HtcpReplyData * htcp, const Ip::Address &from)
1721 {
1722     StoreEntry *e = Store::Root().findCallbackXXX(key);
1723     MemObject *mem = NULL;
1724     CachePeer *p;
1725     peer_t ntype = PEER_NONE;
1726     debugs(15, 6, "neighborsHtcpReply: " <<
1727            (htcp->hit ? "HIT" : "MISS") << " " <<
1728            storeKeyText(key)  );
1729
1730     if (NULL != e)
1731         mem = e->mem_obj;
1732
1733     if ((p = whichPeer(from)))
1734         neighborAliveHtcp(p, mem, htcp);
1735
1736     /* Does the entry exist? */
1737     if (NULL == e) {
1738         debugs(12, 3, "neighyborsHtcpReply: Cache key '" << storeKeyText(key) << "' not found");
1739         neighborCountIgnored(p);
1740         return;
1741     }
1742
1743     /* check if someone is already fetching it */
1744     if (EBIT_TEST(e->flags, ENTRY_DISPATCHED)) {
1745         debugs(15, 3, "neighborsUdpAck: '" << storeKeyText(key) << "' already being fetched.");
1746         neighborCountIgnored(p);
1747         return;
1748     }
1749
1750     if (mem == NULL) {
1751         debugs(15, 2, "Ignoring reply for missing mem_obj: " << storeKeyText(key));
1752         neighborCountIgnored(p);
1753         return;
1754     }
1755
1756     if (e->ping_status != PING_WAITING) {
1757         debugs(15, 2, "neighborsUdpAck: Entry " << storeKeyText(key) << " is not PING_WAITING");
1758         neighborCountIgnored(p);
1759         return;
1760     }
1761
1762     if (!e->locked()) {
1763         // TODO: many entries are unlocked; why is this reported at level 1?
1764         debugs(12, DBG_IMPORTANT, "neighborsUdpAck: '" << storeKeyText(key) << "' has no locks");
1765         neighborCountIgnored(p);
1766         return;
1767     }
1768
1769     if (!mem->ircb_data) {
1770         debugs(12, DBG_IMPORTANT, "BUG: missing HTCP callback data for " << *e);
1771         neighborCountIgnored(p);
1772         return;
1773     }
1774
1775     if (p) {
1776         ntype = neighborType(p, mem->request->url);
1777         neighborUpdateRtt(p, mem);
1778     }
1779
1780     if (ignoreMulticastReply(p, mem->ircb_data)) {
1781         neighborCountIgnored(p);
1782         return;
1783     }
1784
1785     debugs(15, 3, "neighborsHtcpReply: e = " << e);
1786     mem->ping_reply_callback(p, ntype, AnyP::PROTO_HTCP, htcp, mem->ircb_data);
1787 }
1788
1789 /*
1790  * Send HTCP CLR messages to all peers configured to receive them.
1791  */
1792 void
1793 neighborsHtcpClear(StoreEntry * e, const char *uri, HttpRequest * req, const HttpRequestMethod &method, htcp_clr_reason reason)
1794 {
1795     CachePeer *p;
1796     char buf[128];
1797
1798     for (p = Config.peers; p; p = p->next) {
1799         if (!p->options.htcp) {
1800             continue;
1801         }
1802         if (p->options.htcp_no_clr) {
1803             continue;
1804         }
1805         if (p->options.htcp_no_purge_clr && reason == HTCP_CLR_PURGE) {
1806             continue;
1807         }
1808         debugs(15, 3, "neighborsHtcpClear: sending CLR to " << p->in_addr.toUrl(buf, 128));
1809         htcpClear(e, uri, req, method, p, reason);
1810     }
1811 }
1812
1813 #endif
1814