pdns/dnsdist.hh

   1 /*
   2  * This file is part of PowerDNS or dnsdist.
   3  * Copyright -- PowerDNS.COM B.V. and its contributors
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of version 2 of the GNU General Public License as
   7  * published by the Free Software Foundation.
   8  *
   9  * In addition, for the avoidance of any doubt, permission is granted to
  10  * link this program with OpenSSL and to (re)distribute the binaries
  11  * produced as the result of such linking.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  21  */
  22 #pragma once
  23 #include "config.h"
  24 #include "ext/luawrapper/include/LuaContext.hpp"
  25
  26 #include <atomic>
  27 #include <mutex>
  28 #include <string>
  29 #include <thread>
  30 #include <time.h>
  31 #include <unistd.h>
  32 #include <unordered_map>
  33
  34 #include <boost/variant.hpp>
  35
  36 #include "bpf-filter.hh"
  37 #include "capabilities.hh"
  38 #include "circular_buffer.hh"
  39 #include "dnscrypt.hh"
  40 #include "dnsdist-cache.hh"
  41 #include "dnsdist-dynbpf.hh"
  42 #include "dnsname.hh"
  43 #include "doh.hh"
  44 #include "ednsoptions.hh"
  45 #include "gettime.hh"
  46 #include "iputils.hh"
  47 #include "misc.hh"
  48 #include "mplexer.hh"
  49 #include "sholder.hh"
  50 #include "tcpiohandler.hh"
  51 #include "uuid-utils.hh"
  52
  53 void carbonDumpThread();
  54 uint64_t uptimeOfProcess(const std::string& str);
  55
  56 extern uint16_t g_ECSSourcePrefixV4;
  57 extern uint16_t g_ECSSourcePrefixV6;
  58 extern bool g_ECSOverride;
  59
  60 typedef std::unordered_map<string, string> QTag;
  61
  62 struct DNSQuestion
  63 {
  64   DNSQuestion(const DNSName* name, uint16_t type, uint16_t class_, unsigned int consumed_, const ComboAddress* lc, const ComboAddress* rem, struct dnsheader* header, size_t bufferSize, uint16_t queryLen, bool isTcp, const struct timespec* queryTime_):
  65     qname(name), local(lc), remote(rem), dh(header), queryTime(queryTime_), size(bufferSize), consumed(consumed_), tempFailureTTL(boost::none), qtype(type), qclass(class_), len(queryLen), ecsPrefixLength(rem->sin4.sin_family == AF_INET ? g_ECSSourcePrefixV4 : g_ECSSourcePrefixV6), tcp(isTcp), ecsOverride(g_ECSOverride) {
  66     const uint16_t* flags = getFlagsFromDNSHeader(dh);
  67     origFlags = *flags;
  68   }
  69   DNSQuestion(const DNSQuestion&) = delete;
  70   DNSQuestion& operator=(const DNSQuestion&) = delete;
  71   DNSQuestion(DNSQuestion&&) = default;
  72
  73 #ifdef HAVE_PROTOBUF
  74   boost::optional<boost::uuids::uuid> uniqueId;
  75 #endif
  76   Netmask ecs;
  77   boost::optional<Netmask> subnet;
  78   std::string sni; /* Server Name Indication, if any (DoT or DoH) */
  79   std::string poolname;
  80   const DNSName* qname{nullptr};
  81   const ComboAddress* local{nullptr};
  82   const ComboAddress* remote{nullptr};
  83   std::shared_ptr<QTag> qTag{nullptr};
  84   std::shared_ptr<std::map<uint16_t, EDNSOptionView> > ednsOptions;
  85   std::shared_ptr<DNSCryptQuery> dnsCryptQuery{nullptr};
  86   std::shared_ptr<DNSDistPacketCache> packetCache{nullptr};
  87   struct dnsheader* dh{nullptr};
  88   const struct timespec* queryTime{nullptr};
  89   struct DOHUnit* du{nullptr};
  90   size_t size;
  91   unsigned int consumed{0};
  92   int delayMsec{0};
  93   boost::optional<uint32_t> tempFailureTTL;
  94   uint32_t cacheKeyNoECS;
  95   uint32_t cacheKey;
  96   const uint16_t qtype;
  97   const uint16_t qclass;
  98   uint16_t len;
  99   uint16_t ecsPrefixLength;
 100   uint16_t origFlags;
 101   uint8_t ednsRCode{0};
 102   const bool tcp;
 103   bool skipCache{false};
 104   bool ecsOverride;
 105   bool useECS{true};
 106   bool addXPF{true};
 107   bool ecsSet{false};
 108   bool ecsAdded{false};
 109   bool ednsAdded{false};
 110   bool useZeroScope{false};
 111   bool dnssecOK{false};
 112 };
 113
 114 struct DNSResponse : DNSQuestion
 115 {
 116   DNSResponse(const DNSName* name, uint16_t type, uint16_t class_, unsigned int consumed, const ComboAddress* lc, const ComboAddress* rem, struct dnsheader* header, size_t bufferSize, uint16_t responseLen, bool isTcp, const struct timespec* queryTime_):
 117     DNSQuestion(name, type, class_, consumed, lc, rem, header, bufferSize, responseLen, isTcp, queryTime_) { }
 118   DNSResponse(const DNSResponse&) = delete;
 119   DNSResponse& operator=(const DNSResponse&) = delete;
 120   DNSResponse(DNSResponse&&) = default;
 121 };
 122
 123 /* so what could you do:
 124    drop,
 125    fake up nxdomain,
 126    provide actual answer,
 127    allow & and stop processing,
 128    continue processing,
 129    modify header:    (servfail|refused|notimp), set TC=1,
 130    send to pool */
 131
 132 class DNSAction
 133 {
 134 public:
 135   enum class Action { Drop, Nxdomain, Refused, Spoof, Allow, HeaderModify, Pool, Delay, Truncate, ServFail, None, NoOp, NoRecurse };
 136   static std::string typeToString(const Action& action)
 137   {
 138     switch(action) {
 139     case Action::Drop:
 140       return "Drop";
 141     case Action::Nxdomain:
 142       return "Send NXDomain";
 143     case Action::Refused:
 144       return "Send Refused";
 145     case Action::Spoof:
 146       return "Spoof an answer";
 147     case Action::Allow:
 148       return "Allow";
 149     case Action::HeaderModify:
 150       return "Modify the header";
 151     case Action::Pool:
 152       return "Route to a pool";
 153     case Action::Delay:
 154       return "Delay";
 155     case Action::Truncate:
 156       return "Truncate over UDP";
 157     case Action::ServFail:
 158       return "Send ServFail";
 159     case Action::None:
 160     case Action::NoOp:
 161       return "Do nothing";
 162     case Action::NoRecurse:
 163       return "Set rd=0";
 164     }
 165
 166     return "Unknown";
 167   }
 168
 169   virtual Action operator()(DNSQuestion*, string* ruleresult) const =0;
 170   virtual ~DNSAction()
 171   {
 172   }
 173   virtual string toString() const = 0;
 174   virtual std::map<string, double> getStats() const
 175   {
 176     return {{}};
 177   }
 178 };
 179
 180 class DNSResponseAction
 181 {
 182 public:
 183   enum class Action { Allow, Delay, Drop, HeaderModify, ServFail, None };
 184   virtual Action operator()(DNSResponse*, string* ruleresult) const =0;
 185   virtual ~DNSResponseAction()
 186   {
 187   }
 188   virtual string toString() const = 0;
 189 };
 190
 191 struct DynBlock
 192 {
 193   DynBlock(): action(DNSAction::Action::None), warning(false)
 194   {
 195   }
 196
 197   DynBlock(const std::string& reason_, const struct timespec& until_, const DNSName& domain_, DNSAction::Action action_): reason(reason_), until(until_), domain(domain_), action(action_), warning(false)
 198   {
 199   }
 200
 201   DynBlock(const DynBlock& rhs): reason(rhs.reason), until(rhs.until), domain(rhs.domain), action(rhs.action), warning(rhs.warning)
 202   {
 203     blocks.store(rhs.blocks);
 204   }
 205
 206   DynBlock& operator=(const DynBlock& rhs)
 207   {
 208     reason=rhs.reason;
 209     until=rhs.until;
 210     domain=rhs.domain;
 211     action=rhs.action;
 212     blocks.store(rhs.blocks);
 213     warning=rhs.warning;
 214     return *this;
 215   }
 216
 217   string reason;
 218   struct timespec until;
 219   DNSName domain;
 220   DNSAction::Action action;
 221   mutable std::atomic<unsigned int> blocks;
 222   bool warning;
 223 };
 224
 225 extern GlobalStateHolder<NetmaskTree<DynBlock>> g_dynblockNMG;
 226
 227 extern vector<pair<struct timeval, std::string> > g_confDelta;
 228
 229 extern uint64_t getLatencyCount(const std::string&);
 230
 231 struct DNSDistStats
 232 {
 233   using stat_t=std::atomic<uint64_t>; // aww yiss ;-)
 234   stat_t responses{0};
 235   stat_t servfailResponses{0};
 236   stat_t queries{0};
 237   stat_t frontendNXDomain{0};
 238   stat_t frontendServFail{0};
 239   stat_t frontendNoError{0};
 240   stat_t nonCompliantQueries{0};
 241   stat_t nonCompliantResponses{0};
 242   stat_t rdQueries{0};
 243   stat_t emptyQueries{0};
 244   stat_t aclDrops{0};
 245   stat_t dynBlocked{0};
 246   stat_t ruleDrop{0};
 247   stat_t ruleNXDomain{0};
 248   stat_t ruleRefused{0};
 249   stat_t ruleServFail{0};
 250   stat_t selfAnswered{0};
 251   stat_t downstreamTimeouts{0};
 252   stat_t downstreamSendErrors{0};
 253   stat_t truncFail{0};
 254   stat_t noPolicy{0};
 255   stat_t cacheHits{0};
 256   stat_t cacheMisses{0};
 257   stat_t latency0_1{0}, latency1_10{0}, latency10_50{0}, latency50_100{0}, latency100_1000{0}, latencySlow{0}, latencySum{0};
 258   stat_t securityStatus{0};
 259
 260   double latencyAvg100{0}, latencyAvg1000{0}, latencyAvg10000{0}, latencyAvg1000000{0};
 261   typedef std::function<uint64_t(const std::string&)> statfunction_t;
 262   typedef boost::variant<stat_t*, double*, statfunction_t> entry_t;
 263   std::vector<std::pair<std::string, entry_t>> entries{
 264     {"responses", &responses},
 265     {"servfail-responses", &servfailResponses},
 266     {"queries", &queries},
 267     {"frontend-nxdomain", &frontendNXDomain},
 268     {"frontend-servfail", &frontendServFail},
 269     {"frontend-noerror", &frontendNoError},
 270     {"acl-drops", &aclDrops},
 271     {"rule-drop", &ruleDrop},
 272     {"rule-nxdomain", &ruleNXDomain},
 273     {"rule-refused", &ruleRefused},
 274     {"rule-servfail", &ruleServFail},
 275     {"self-answered", &selfAnswered},
 276     {"downstream-timeouts", &downstreamTimeouts},
 277     {"downstream-send-errors", &downstreamSendErrors},
 278     {"trunc-failures", &truncFail},
 279     {"no-policy", &noPolicy},
 280     {"latency0-1", &latency0_1},
 281     {"latency1-10", &latency1_10},
 282     {"latency10-50", &latency10_50},
 283     {"latency50-100", &latency50_100},
 284     {"latency100-1000", &latency100_1000},
 285     {"latency-slow", &latencySlow},
 286     {"latency-avg100", &latencyAvg100},
 287     {"latency-avg1000", &latencyAvg1000},
 288     {"latency-avg10000", &latencyAvg10000},
 289     {"latency-avg1000000", &latencyAvg1000000},
 290     {"uptime", uptimeOfProcess},
 291     {"real-memory-usage", getRealMemoryUsage},
 292     {"special-memory-usage", getSpecialMemoryUsage},
 293     {"noncompliant-queries", &nonCompliantQueries},
 294     {"noncompliant-responses", &nonCompliantResponses},
 295     {"rdqueries", &rdQueries},
 296     {"empty-queries", &emptyQueries},
 297     {"cache-hits", &cacheHits},
 298     {"cache-misses", &cacheMisses},
 299     {"cpu-user-msec", getCPUTimeUser},
 300     {"cpu-sys-msec", getCPUTimeSystem},
 301     {"fd-usage", getOpenFileDescriptors},
 302     {"dyn-blocked", &dynBlocked},
 303     {"dyn-block-nmg-size", [](const std::string&) { return g_dynblockNMG.getLocal()->size(); }},
 304     {"security-status", &securityStatus},
 305     // Latency histogram
 306     {"latency-sum", &latencySum},
 307     {"latency-count", getLatencyCount},
 308   };
 309 };
 310
 311 // Metric types for Prometheus
 312 enum class PrometheusMetricType: int {
 313     counter = 1,
 314     gauge = 2
 315 };
 316
 317 // Keeps additional information about metrics
 318 struct MetricDefinition {
 319   MetricDefinition(PrometheusMetricType _prometheusType, const std::string& _description): description(_description), prometheusType(_prometheusType) {
 320   }
 321
 322   MetricDefinition() = default;
 323
 324   // Metric description
 325   std::string description;
 326   // Metric type for Prometheus
 327   PrometheusMetricType prometheusType;
 328 };
 329
 330 struct MetricDefinitionStorage {
 331   // Return metric definition by name
 332   bool getMetricDetails(std::string metricName, MetricDefinition& metric) {
 333   auto metricDetailsIter = metrics.find(metricName);
 334
 335   if (metricDetailsIter == metrics.end()) {
 336     return false;
 337   }
 338
 339   metric = metricDetailsIter->second;
 340     return true;
 341   };
 342
 343   // Return string representation of Prometheus metric type
 344   std::string getPrometheusStringMetricType(PrometheusMetricType metricType) {
 345     switch (metricType) {
 346       case PrometheusMetricType::counter:
 347         return "counter";
 348         break;
 349       case PrometheusMetricType::gauge:
 350         return "gauge";
 351         break;
 352       default:
 353         return "";
 354         break;
 355     }
 356   };
 357
 358   std::map<std::string, MetricDefinition> metrics = {
 359     { "responses",              MetricDefinition(PrometheusMetricType::counter, "Number of responses received from backends") },
 360     { "servfail-responses",     MetricDefinition(PrometheusMetricType::counter, "Number of SERVFAIL answers received from backends") },
 361     { "queries",                MetricDefinition(PrometheusMetricType::counter, "Number of received queries")},
 362     { "frontend-nxdomain",      MetricDefinition(PrometheusMetricType::counter, "Number of NXDomain answers sent to clients")},
 363     { "frontend-servfail",      MetricDefinition(PrometheusMetricType::counter, "Number of SERVFAIL answers sent to clients")},
 364     { "frontend-noerror",       MetricDefinition(PrometheusMetricType::counter, "Number of NoError answers sent to clients")},
 365     { "acl-drops",              MetricDefinition(PrometheusMetricType::counter, "Number of packets dropped because of the ACL")},
 366     { "rule-drop",              MetricDefinition(PrometheusMetricType::counter, "Number of queries dropped because of a rule")},
 367     { "rule-nxdomain",          MetricDefinition(PrometheusMetricType::counter, "Number of NXDomain answers returned because of a rule")},
 368     { "rule-refused",           MetricDefinition(PrometheusMetricType::counter, "Number of Refused answers returned because of a rule")},
 369     { "rule-servfail",          MetricDefinition(PrometheusMetricType::counter, "Number of SERVFAIL answers received because of a rule")},
 370     { "self-answered",          MetricDefinition(PrometheusMetricType::counter, "Number of self-answered responses")},
 371     { "downstream-timeouts",    MetricDefinition(PrometheusMetricType::counter, "Number of queries not answered in time by a backend")},
 372     { "downstream-send-errors", MetricDefinition(PrometheusMetricType::counter, "Number of errors when sending a query to a backend")},
 373     { "trunc-failures",         MetricDefinition(PrometheusMetricType::counter, "Number of errors encountered while truncating an answer")},
 374     { "no-policy",              MetricDefinition(PrometheusMetricType::counter, "Number of queries dropped because no server was available")},
 375     { "latency0-1",             MetricDefinition(PrometheusMetricType::counter, "Number of queries answered in less than 1ms")},
 376     { "latency1-10",            MetricDefinition(PrometheusMetricType::counter, "Number of queries answered in 1-10 ms")},
 377     { "latency10-50",           MetricDefinition(PrometheusMetricType::counter, "Number of queries answered in 10-50 ms")},
 378     { "latency50-100",          MetricDefinition(PrometheusMetricType::counter, "Number of queries answered in 50-100 ms")},
 379     { "latency100-1000",        MetricDefinition(PrometheusMetricType::counter, "Number of queries answered in 100-1000 ms")},
 380     { "latency-slow",           MetricDefinition(PrometheusMetricType::counter, "Number of queries answered in more than 1 second")},
 381     { "latency-avg100",         MetricDefinition(PrometheusMetricType::gauge,   "Average response latency in microseconds of the last 100 packets")},
 382     { "latency-avg1000",        MetricDefinition(PrometheusMetricType::gauge,   "Average response latency in microseconds of the last 1000 packets")},
 383     { "latency-avg10000",       MetricDefinition(PrometheusMetricType::gauge,   "Average response latency in microseconds of the last 10000 packets")},
 384     { "latency-avg1000000",     MetricDefinition(PrometheusMetricType::gauge,   "Average response latency in microseconds of the last 1000000 packets")},
 385     { "uptime",                 MetricDefinition(PrometheusMetricType::gauge,   "Uptime of the dnsdist process in seconds")},
 386     { "real-memory-usage",      MetricDefinition(PrometheusMetricType::gauge,   "Current memory usage in bytes")},
 387     { "noncompliant-queries",   MetricDefinition(PrometheusMetricType::counter, "Number of queries dropped as non-compliant")},
 388     { "noncompliant-responses", MetricDefinition(PrometheusMetricType::counter, "Number of answers from a backend dropped as non-compliant")},
 389     { "rdqueries",              MetricDefinition(PrometheusMetricType::counter, "Number of received queries with the recursion desired bit set")},
 390     { "empty-queries",          MetricDefinition(PrometheusMetricType::counter, "Number of empty queries received from clients")},
 391     { "cache-hits",             MetricDefinition(PrometheusMetricType::counter, "Number of times an answer was retrieved from cache")},
 392     { "cache-misses",           MetricDefinition(PrometheusMetricType::counter, "Number of times an answer not found in the cache")},
 393     { "cpu-user-msec",          MetricDefinition(PrometheusMetricType::counter, "Milliseconds spent by dnsdist in the user state")},
 394     { "cpu-sys-msec",           MetricDefinition(PrometheusMetricType::counter, "Milliseconds spent by dnsdist in the system state")},
 395     { "fd-usage",               MetricDefinition(PrometheusMetricType::gauge,   "Number of currently used file descriptors")},
 396     { "dyn-blocked",            MetricDefinition(PrometheusMetricType::counter, "Number of queries dropped because of a dynamic block")},
 397     { "dyn-block-nmg-size",     MetricDefinition(PrometheusMetricType::gauge,   "Number of dynamic blocks entries") },
 398     { "security-status",        MetricDefinition(PrometheusMetricType::gauge,   "Security status of this software. 0=unknown, 1=OK, 2=upgrade recommended, 3=upgrade mandatory") },
 399   };
 400 };
 401
 402 extern MetricDefinitionStorage g_metricDefinitions;
 403 extern struct DNSDistStats g_stats;
 404 void doLatencyStats(double udiff);
 405
 406
 407 struct StopWatch
 408 {
 409   StopWatch(bool realTime=false): d_needRealTime(realTime)
 410   {
 411   }
 412   struct timespec d_start{0,0};
 413   bool d_needRealTime{false};
 414
 415   void start() {
 416     if(gettime(&d_start, d_needRealTime) < 0)
 417       unixDie("Getting timestamp");
 418
 419   }
 420
 421   void set(const struct timespec& from) {
 422     d_start = from;
 423   }
 424
 425   double udiff() const {
 426     struct timespec now;
 427     if(gettime(&now, d_needRealTime) < 0)
 428       unixDie("Getting timestamp");
 429
 430     return 1000000.0*(now.tv_sec - d_start.tv_sec) + (now.tv_nsec - d_start.tv_nsec)/1000.0;
 431   }
 432
 433   double udiffAndSet() {
 434     struct timespec now;
 435     if(gettime(&now, d_needRealTime) < 0)
 436       unixDie("Getting timestamp");
 437
 438     auto ret= 1000000.0*(now.tv_sec - d_start.tv_sec) + (now.tv_nsec - d_start.tv_nsec)/1000.0;
 439     d_start = now;
 440     return ret;
 441   }
 442
 443 };
 444
 445 class BasicQPSLimiter
 446 {
 447 public:
 448   BasicQPSLimiter()
 449   {
 450   }
 451
 452   BasicQPSLimiter(unsigned int burst): d_tokens(burst)
 453   {
 454     d_prev.start();
 455   }
 456
 457   bool check(unsigned int rate, unsigned int burst) const // this is not quite fair
 458   {
 459     auto delta = d_prev.udiffAndSet();
 460
 461     if(delta > 0.0) // time, frequently, does go backwards..
 462       d_tokens += 1.0 * rate * (delta/1000000.0);
 463
 464     if(d_tokens > burst) {
 465       d_tokens = burst;
 466     }
 467
 468     bool ret=false;
 469     if(d_tokens >= 1.0) { // we need this because burst=1 is weird otherwise
 470       ret=true;
 471       --d_tokens;
 472     }
 473
 474     return ret;
 475   }
 476
 477   bool seenSince(const struct timespec& cutOff) const
 478   {
 479     return cutOff < d_prev.d_start;
 480   }
 481
 482 protected:
 483   mutable StopWatch d_prev;
 484   mutable double d_tokens;
 485 };
 486
 487 class QPSLimiter : public BasicQPSLimiter
 488 {
 489 public:
 490   QPSLimiter(): BasicQPSLimiter()
 491   {
 492   }
 493
 494   QPSLimiter(unsigned int rate, unsigned int burst): BasicQPSLimiter(burst), d_rate(rate), d_burst(burst), d_passthrough(false)
 495   {
 496     d_prev.start();
 497   }
 498
 499   unsigned int getRate() const
 500   {
 501     return d_passthrough ? 0 : d_rate;
 502   }
 503
 504   int getPassed() const
 505   {
 506     return d_passed;
 507   }
 508
 509   int getBlocked() const
 510   {
 511     return d_blocked;
 512   }
 513
 514   bool check() const // this is not quite fair
 515   {
 516     if (d_passthrough) {
 517       return true;
 518     }
 519
 520     bool ret = BasicQPSLimiter::check(d_rate, d_burst);
 521     if (ret) {
 522       d_passed++;
 523     }
 524     else {
 525       d_blocked++;
 526     }
 527
 528     return ret;
 529   }
 530 private:
 531   mutable unsigned int d_passed{0};
 532   mutable unsigned int d_blocked{0};
 533   unsigned int d_rate;
 534   unsigned int d_burst;
 535   bool d_passthrough{true};
 536 };
 537
 538 struct ClientState;
 539
 540 struct IDState
 541 {
 542   IDState(): sentTime(true), delayMsec(0), tempFailureTTL(boost::none) { origDest.sin4.sin_family = 0;}
 543   IDState(const IDState& orig): origRemote(orig.origRemote), origDest(orig.origDest), age(orig.age)
 544   {
 545     usageIndicator.store(orig.usageIndicator.load());
 546     origFD = orig.origFD;
 547     origID = orig.origID;
 548     delayMsec = orig.delayMsec;
 549     tempFailureTTL = orig.tempFailureTTL;
 550   }
 551
 552   static const int64_t unusedIndicator = -1;
 553
 554   static bool isInUse(int64_t usageIndicator)
 555   {
 556     return usageIndicator != unusedIndicator;
 557   }
 558
 559   bool isInUse() const
 560   {
 561     return usageIndicator != unusedIndicator;
 562   }
 563
 564   /* return true if the value has been successfully replaced meaning that
 565      no-one updated the usage indicator in the meantime */
 566   bool tryMarkUnused(int64_t expectedUsageIndicator)
 567   {
 568     return usageIndicator.compare_exchange_strong(expectedUsageIndicator, unusedIndicator);
 569   }
 570
 571   /* mark as unused no matter what, return true if the state was in use before */
 572   bool markAsUsed()
 573   {
 574     auto currentGeneration = generation++;
 575     return markAsUsed(currentGeneration);
 576   }
 577
 578   /* mark as unused no matter what, return true if the state was in use before */
 579   bool markAsUsed(int64_t currentGeneration)
 580   {
 581     int64_t oldUsage = usageIndicator.exchange(currentGeneration);
 582     return oldUsage != unusedIndicator;
 583   }
 584
 585   /* We use this value to detect whether this state is in use.
 586      For performance reasons we don't want to use a lock here, but that means
 587      we need to be very careful when modifying this value. Modifications happen
 588      from:
 589      - one of the UDP or DoH 'client' threads receiving a query, selecting a backend
 590        then picking one of the states associated to this backend (via the idOffset).
 591        Most of the time this state should not be in use and usageIndicator is -1, but we
 592        might not yet have received a response for the query previously associated to this
 593        state, meaning that we will 'reuse' this state and erase the existing state.
 594        If we ever receive a response for this state, it will be discarded. This is
 595        mostly fine for UDP except that we still need to be careful in order to miss
 596        the 'outstanding' counters, which should only be increased when we are picking
 597        an empty state, and not when reusing ;
 598        For DoH, though, we have dynamically allocated a DOHUnit object that needs to
 599        be freed, as well as internal objects internals to libh2o.
 600      - one of the UDP receiver threads receiving a response from a backend, picking
 601        the corresponding state and sending the response to the client ;
 602      - the 'healthcheck' thread scanning the states to actively discover timeouts,
 603        mostly to keep some counters like the 'outstanding' one sane.
 604      We previously based that logic on the origFD (FD on which the query was received,
 605      and therefore from where the response should be sent) but this suffered from an
 606      ABA problem since it was quite likely that a UDP 'client thread' would reset it to the
 607      same value since we only have so much incoming sockets:
 608      - 1/ 'client' thread gets a query and set origFD to its FD, say 5 ;
 609      - 2/ 'receiver' thread gets a response, read the value of origFD to 5, check that the qname,
 610        qtype and qclass match
 611      - 3/ during that time the 'client' thread reuses the state, setting again origFD to 5 ;
 612      - 4/ the 'receiver' thread uses compare_exchange_strong() to only replace the value if it's still
 613        5, except it's not the same 5 anymore and it overrides a fresh state.
 614      We now use a 32-bit unsigned counter instead, which is incremented every time the state is set,
 615      wrapping around if necessary, and we set an atomic signed 64-bit value, so that we still have -1
 616      when the state is unused and the value of our counter otherwise.
 617   */
 618   std::atomic<int64_t> usageIndicator{unusedIndicator};  // set to unusedIndicator to indicate this state is empty   // 8
 619   std::atomic<uint32_t> generation{0}; // increased every time a state is used, to be able to detect an ABA issue    // 4
 620   ComboAddress origRemote;                                    // 28
 621   ComboAddress origDest;                                      // 28
 622   StopWatch sentTime;                                         // 16
 623   DNSName qname;                                              // 80
 624   std::shared_ptr<DNSCryptQuery> dnsCryptQuery{nullptr};
 625 #ifdef HAVE_PROTOBUF
 626   boost::optional<boost::uuids::uuid> uniqueId;
 627 #endif
 628   boost::optional<Netmask> subnet{boost::none};
 629   std::shared_ptr<DNSDistPacketCache> packetCache{nullptr};
 630   std::shared_ptr<QTag> qTag{nullptr};
 631   const ClientState* cs{nullptr};
 632   DOHUnit* du{nullptr};
 633   uint32_t cacheKey;                                          // 4
 634   uint32_t cacheKeyNoECS;                                     // 4
 635   uint16_t age;                                               // 4
 636   uint16_t qtype;                                             // 2
 637   uint16_t qclass;                                            // 2
 638   uint16_t origID;                                            // 2
 639   uint16_t origFlags;                                         // 2
 640   int origFD{-1};
 641   int delayMsec;
 642   boost::optional<uint32_t> tempFailureTTL;
 643   bool ednsAdded{false};
 644   bool ecsAdded{false};
 645   bool skipCache{false};
 646   bool destHarvested{false}; // if true, origDest holds the original dest addr, otherwise the listening addr
 647   bool dnssecOK{false};
 648   bool useZeroScope;
 649 };
 650
 651 typedef std::unordered_map<string, unsigned int> QueryCountRecords;
 652 typedef std::function<std::tuple<bool, string>(const DNSQuestion* dq)> QueryCountFilter;
 653 struct QueryCount {
 654   QueryCount()
 655   {
 656     pthread_rwlock_init(&queryLock, nullptr);
 657   }
 658   QueryCountRecords records;
 659   QueryCountFilter filter;
 660   pthread_rwlock_t queryLock;
 661   bool enabled{false};
 662 };
 663
 664 extern QueryCount g_qcount;
 665
 666 struct ClientState
 667 {
 668   ClientState(const ComboAddress& local_, bool isTCP, bool doReusePort, int fastOpenQueue, const std::string& itfName, const std::set<int>& cpus_): cpus(cpus_), local(local_), interface(itfName), fastOpenQueueSize(fastOpenQueue), tcp(isTCP), reuseport(doReusePort)
 669   {
 670   }
 671
 672   std::set<int> cpus;
 673   ComboAddress local;
 674   std::shared_ptr<DNSCryptContext> dnscryptCtx{nullptr};
 675   std::shared_ptr<TLSFrontend> tlsFrontend{nullptr};
 676   std::shared_ptr<DOHFrontend> dohFrontend{nullptr};
 677   std::string interface;
 678   std::atomic<uint64_t> queries{0};
 679   mutable std::atomic<uint64_t> responses{0};
 680   std::atomic<uint64_t> tcpDiedReadingQuery{0};
 681   std::atomic<uint64_t> tcpDiedSendingResponse{0};
 682   std::atomic<uint64_t> tcpGaveUp{0};
 683   std::atomic<uint64_t> tcpClientTimeouts{0};
 684   std::atomic<uint64_t> tcpDownstreamTimeouts{0};
 685   std::atomic<uint64_t> tcpCurrentConnections{0};
 686   std::atomic<uint64_t> tlsNewSessions{0}; // A new TLS session has been negotiated, no resumption
 687   std::atomic<uint64_t> tlsResumptions{0}; // A TLS session has been resumed, either via session id or via a TLS ticket
 688
 689   std::atomic<double> tcpAvgQueriesPerConnection{0.0};
 690   /* in ms */
 691   std::atomic<double> tcpAvgConnectionDuration{0.0};
 692   int udpFD{-1};
 693   int tcpFD{-1};
 694   int fastOpenQueueSize{0};
 695   bool muted{false};
 696   bool tcp;
 697   bool reuseport;
 698   bool ready{false};
 699
 700   int getSocket() const
 701   {
 702     return udpFD != -1 ? udpFD : tcpFD;
 703   }
 704
 705   bool isUDP() const
 706   {
 707     return udpFD != -1;
 708   }
 709
 710   bool isTCP() const
 711   {
 712     return udpFD == -1;
 713   }
 714
 715   std::string getType() const
 716   {
 717     std::string result = udpFD != -1 ? "UDP" : "TCP";
 718
 719     if (dohFrontend) {
 720       result += " (DNS over HTTPS)";
 721     }
 722     else if (tlsFrontend) {
 723       result += " (DNS over TLS)";
 724     }
 725     else if (dnscryptCtx) {
 726       result += " (DNSCrypt)";
 727     }
 728
 729     return result;
 730   }
 731
 732 #ifdef HAVE_EBPF
 733   shared_ptr<BPFFilter> d_filter;
 734
 735   void detachFilter()
 736   {
 737     if (d_filter) {
 738       d_filter->removeSocket(getSocket());
 739       d_filter = nullptr;
 740     }
 741   }
 742
 743   void attachFilter(shared_ptr<BPFFilter> bpf)
 744   {
 745     detachFilter();
 746
 747     bpf->addSocket(getSocket());
 748     d_filter = bpf;
 749   }
 750 #endif /* HAVE_EBPF */
 751
 752   void updateTCPMetrics(size_t queries, uint64_t durationMs)
 753   {
 754     tcpAvgQueriesPerConnection = (99.0 * tcpAvgQueriesPerConnection / 100.0) + (queries / 100.0);
 755     tcpAvgConnectionDuration = (99.0 * tcpAvgConnectionDuration / 100.0) + (durationMs / 100.0);
 756   }
 757 };
 758
 759 class TCPClientCollection {
 760   std::vector<int> d_tcpclientthreads;
 761   std::atomic<uint64_t> d_numthreads{0};
 762   std::atomic<uint64_t> d_pos{0};
 763   std::atomic<uint64_t> d_queued{0};
 764   const uint64_t d_maxthreads{0};
 765   std::mutex d_mutex;
 766   int d_singlePipe[2];
 767   const bool d_useSinglePipe;
 768 public:
 769
 770   TCPClientCollection(size_t maxThreads, bool useSinglePipe=false): d_maxthreads(maxThreads), d_singlePipe{-1,-1}, d_useSinglePipe(useSinglePipe)
 771
 772   {
 773     d_tcpclientthreads.reserve(maxThreads);
 774
 775     if (d_useSinglePipe) {
 776       if (pipe(d_singlePipe) < 0) {
 777         int err = errno;
 778         throw std::runtime_error("Error creating the TCP single communication pipe: " + stringerror(err));
 779       }
 780
 781       if (!setNonBlocking(d_singlePipe[0])) {
 782         int err = errno;
 783         close(d_singlePipe[0]);
 784         close(d_singlePipe[1]);
 785         throw std::runtime_error("Error setting the TCP single communication pipe non-blocking: " + stringerror(err));
 786       }
 787
 788       if (!setNonBlocking(d_singlePipe[1])) {
 789         int err = errno;
 790         close(d_singlePipe[0]);
 791         close(d_singlePipe[1]);
 792         throw std::runtime_error("Error setting the TCP single communication pipe non-blocking: " + stringerror(err));
 793       }
 794     }
 795   }
 796   int getThread()
 797   {
 798     uint64_t pos = d_pos++;
 799     ++d_queued;
 800     return d_tcpclientthreads[pos % d_numthreads];
 801   }
 802   bool hasReachedMaxThreads() const
 803   {
 804     return d_numthreads >= d_maxthreads;
 805   }
 806   uint64_t getThreadsCount() const
 807   {
 808     return d_numthreads;
 809   }
 810   uint64_t getQueuedCount() const
 811   {
 812     return d_queued;
 813   }
 814   void decrementQueuedCount()
 815   {
 816     --d_queued;
 817   }
 818   void addTCPClientThread();
 819 };
 820
 821 extern std::unique_ptr<TCPClientCollection> g_tcpclientthreads;
 822
 823 struct DownstreamState
 824 {
 825    typedef std::function<std::tuple<DNSName, uint16_t, uint16_t>(const DNSName&, uint16_t, uint16_t, dnsheader*)> checkfunc_t;
 826
 827   DownstreamState(const ComboAddress& remote_, const ComboAddress& sourceAddr_, unsigned int sourceItf, const std::string& sourceItfName, size_t numberOfSockets);
 828   DownstreamState(const ComboAddress& remote_): DownstreamState(remote_, ComboAddress(), 0, std::string(), 1) {}
 829   ~DownstreamState()
 830   {
 831     for (auto& fd : sockets) {
 832       if (fd >= 0) {
 833         close(fd);
 834         fd = -1;
 835       }
 836     }
 837   }
 838   boost::uuids::uuid id;
 839   std::set<unsigned int> hashes;
 840   mutable pthread_rwlock_t d_lock;
 841   std::vector<int> sockets;
 842   const std::string sourceItfName;
 843   std::mutex socketsLock;
 844   std::mutex connectLock;
 845   std::unique_ptr<FDMultiplexer> mplexer{nullptr};
 846   std::thread tid;
 847   const ComboAddress remote;
 848   QPSLimiter qps;
 849   vector<IDState> idStates;
 850   const ComboAddress sourceAddr;
 851   checkfunc_t checkFunction;
 852   DNSName checkName{"a.root-servers.net."};
 853   QType checkType{QType::A};
 854   uint16_t checkClass{QClass::IN};
 855   std::atomic<uint64_t> idOffset{0};
 856   std::atomic<uint64_t> sendErrors{0};
 857   std::atomic<uint64_t> outstanding{0};
 858   std::atomic<uint64_t> reuseds{0};
 859   std::atomic<uint64_t> queries{0};
 860   std::atomic<uint64_t> responses{0};
 861   struct {
 862     std::atomic<uint64_t> sendErrors{0};
 863     std::atomic<uint64_t> reuseds{0};
 864     std::atomic<uint64_t> queries{0};
 865   } prev;
 866   std::atomic<uint64_t> tcpDiedSendingQuery{0};
 867   std::atomic<uint64_t> tcpDiedReadingResponse{0};
 868   std::atomic<uint64_t> tcpGaveUp{0};
 869   std::atomic<uint64_t> tcpReadTimeouts{0};
 870   std::atomic<uint64_t> tcpWriteTimeouts{0};
 871   std::atomic<uint64_t> tcpCurrentConnections{0};
 872   std::atomic<double> tcpAvgQueriesPerConnection{0.0};
 873   /* in ms */
 874   std::atomic<double> tcpAvgConnectionDuration{0.0};
 875   string name;
 876   size_t socketsOffset{0};
 877   double queryLoad{0.0};
 878   double dropRate{0.0};
 879   double latencyUsec{0.0};
 880   int order{1};
 881   int weight{1};
 882   int tcpConnectTimeout{5};
 883   int tcpRecvTimeout{30};
 884   int tcpSendTimeout{30};
 885   unsigned int checkInterval{1};
 886   unsigned int lastCheck{0};
 887   const unsigned int sourceItf{0};
 888   uint16_t retries{5};
 889   uint16_t xpfRRCode{0};
 890   uint16_t checkTimeout{1000}; /* in milliseconds */
 891   uint8_t currentCheckFailures{0};
 892   uint8_t consecutiveSuccessfulChecks{0};
 893   uint8_t maxCheckFailures{1};
 894   uint8_t minRiseSuccesses{1};
 895   StopWatch sw;
 896   set<string> pools;
 897   enum class Availability { Up, Down, Auto} availability{Availability::Auto};
 898   bool mustResolve{false};
 899   bool upStatus{false};
 900   bool useECS{false};
 901   bool setCD{false};
 902   bool disableZeroScope{false};
 903   std::atomic<bool> connected{false};
 904   std::atomic_flag threadStarted;
 905   bool tcpFastOpen{false};
 906   bool ipBindAddrNoPort{true};
 907
 908   bool isUp() const
 909   {
 910     if(availability == Availability::Down)
 911       return false;
 912     if(availability == Availability::Up)
 913       return true;
 914     return upStatus;
 915   }
 916   void setUp() { availability = Availability::Up; }
 917   void setDown() { availability = Availability::Down; }
 918   void setAuto() { availability = Availability::Auto; }
 919   string getName() const {
 920     if (name.empty()) {
 921       return remote.toStringWithPort();
 922     }
 923     return name;
 924   }
 925   string getNameWithAddr() const {
 926     if (name.empty()) {
 927       return remote.toStringWithPort();
 928     }
 929     return name + " (" + remote.toStringWithPort()+ ")";
 930   }
 931   string getStatus() const
 932   {
 933     string status;
 934     if(availability == DownstreamState::Availability::Up)
 935       status = "UP";
 936     else if(availability == DownstreamState::Availability::Down)
 937       status = "DOWN";
 938     else
 939       status = (upStatus ? "up" : "down");
 940     return status;
 941   }
 942   bool reconnect();
 943   void hash();
 944   void setId(const boost::uuids::uuid& newId);
 945   void setWeight(int newWeight);
 946
 947   void updateTCPMetrics(size_t queries, uint64_t durationMs)
 948   {
 949     tcpAvgQueriesPerConnection = (99.0 * tcpAvgQueriesPerConnection / 100.0) + (queries / 100.0);
 950     tcpAvgConnectionDuration = (99.0 * tcpAvgConnectionDuration / 100.0) + (durationMs / 100.0);
 951   }
 952 };
 953 using servers_t =vector<std::shared_ptr<DownstreamState>>;
 954
 955 template <class T> using NumberedVector = std::vector<std::pair<unsigned int, T> >;
 956
 957 void responderThread(std::shared_ptr<DownstreamState> state);
 958 extern std::mutex g_luamutex;
 959 extern LuaContext g_lua;
 960 extern std::string g_outputBuffer; // locking for this is ok, as locked by g_luamutex
 961
 962 class DNSRule
 963 {
 964 public:
 965   virtual ~DNSRule ()
 966   {
 967   }
 968   virtual bool matches(const DNSQuestion* dq) const =0;
 969   virtual string toString() const = 0;
 970   mutable std::atomic<uint64_t> d_matches{0};
 971 };
 972
 973 using NumberedServerVector = NumberedVector<shared_ptr<DownstreamState>>;
 974 typedef std::function<shared_ptr<DownstreamState>(const NumberedServerVector& servers, const DNSQuestion*)> policyfunc_t;
 975
 976 struct ServerPolicy
 977 {
 978   string name;
 979   policyfunc_t policy;
 980   bool isLua;
 981   std::string toString() const {
 982     return string("ServerPolicy") + (isLua ? " (Lua)" : "") + " \"" + name + "\"";
 983   }
 984 };
 985
 986 struct ServerPool
 987 {
 988   ServerPool()
 989   {
 990     pthread_rwlock_init(&d_lock, nullptr);
 991   }
 992
 993   const std::shared_ptr<DNSDistPacketCache> getCache() const { return packetCache; };
 994
 995   bool getECS() const
 996   {
 997     return d_useECS;
 998   }
 999
1000   void setECS(bool useECS)
1001   {
1002     d_useECS = useECS;
1003   }
1004
1005   std::shared_ptr<DNSDistPacketCache> packetCache{nullptr};
1006   std::shared_ptr<ServerPolicy> policy{nullptr};
1007
1008   size_t countServers(bool upOnly)
1009   {
1010     size_t count = 0;
1011     ReadLock rl(&d_lock);
1012     for (const auto& server : d_servers) {
1013       if (!upOnly || std::get<1>(server)->isUp() ) {
1014         count++;
1015       }
1016     }
1017     return count;
1018   }
1019
1020   NumberedVector<shared_ptr<DownstreamState>> getServers()
1021   {
1022     NumberedVector<shared_ptr<DownstreamState>> result;
1023     {
1024       ReadLock rl(&d_lock);
1025       result = d_servers;
1026     }
1027     return result;
1028   }
1029
1030   void addServer(shared_ptr<DownstreamState>& server)
1031   {
1032     WriteLock wl(&d_lock);
1033     unsigned int count = (unsigned int) d_servers.size();
1034     d_servers.push_back(make_pair(++count, server));
1035     /* we need to reorder based on the server 'order' */
1036     std::stable_sort(d_servers.begin(), d_servers.end(), [](const std::pair<unsigned int,std::shared_ptr<DownstreamState> >& a, const std::pair<unsigned int,std::shared_ptr<DownstreamState> >& b) {
1037       return a.second->order < b.second->order;
1038     });
1039     /* and now we need to renumber for Lua (custom policies) */
1040     size_t idx = 1;
1041     for (auto& serv : d_servers) {
1042       serv.first = idx++;
1043     }
1044   }
1045
1046   void removeServer(shared_ptr<DownstreamState>& server)
1047   {
1048     WriteLock wl(&d_lock);
1049     size_t idx = 1;
1050     bool found = false;
1051     for (auto it = d_servers.begin(); it != d_servers.end();) {
1052       if (found) {
1053         /* we need to renumber the servers placed
1054            after the removed one, for Lua (custom policies) */
1055         it->first = idx++;
1056         it++;
1057       }
1058       else if (it->second == server) {
1059         it = d_servers.erase(it);
1060         found = true;
1061       } else {
1062         idx++;
1063         it++;
1064       }
1065     }
1066   }
1067
1068 private:
1069   NumberedVector<shared_ptr<DownstreamState>> d_servers;
1070   pthread_rwlock_t d_lock;
1071   bool d_useECS{false};
1072 };
1073 using pools_t=map<std::string,std::shared_ptr<ServerPool>>;
1074 void setPoolPolicy(pools_t& pools, const string& poolName, std::shared_ptr<ServerPolicy> policy);
1075 void addServerToPool(pools_t& pools, const string& poolName, std::shared_ptr<DownstreamState> server);
1076 void removeServerFromPool(pools_t& pools, const string& poolName, std::shared_ptr<DownstreamState> server);
1077
1078 struct CarbonConfig
1079 {
1080   ComboAddress server;
1081   std::string namespace_name;
1082   std::string ourname;
1083   std::string instance_name;
1084   unsigned int interval;
1085 };
1086
1087 enum ednsHeaderFlags {
1088   EDNS_HEADER_FLAG_NONE = 0,
1089   EDNS_HEADER_FLAG_DO = 32768
1090 };
1091
1092 struct DNSDistRuleAction
1093 {
1094   std::shared_ptr<DNSRule> d_rule;
1095   std::shared_ptr<DNSAction> d_action;
1096   boost::uuids::uuid d_id;
1097   uint64_t d_creationOrder;
1098 };
1099
1100 struct DNSDistResponseRuleAction
1101 {
1102   std::shared_ptr<DNSRule> d_rule;
1103   std::shared_ptr<DNSResponseAction> d_action;
1104   boost::uuids::uuid d_id;
1105   uint64_t d_creationOrder;
1106 };
1107
1108 extern GlobalStateHolder<SuffixMatchTree<DynBlock>> g_dynblockSMT;
1109 extern DNSAction::Action g_dynBlockAction;
1110
1111 extern GlobalStateHolder<vector<CarbonConfig> > g_carbon;
1112 extern GlobalStateHolder<ServerPolicy> g_policy;
1113 extern GlobalStateHolder<servers_t> g_dstates;
1114 extern GlobalStateHolder<pools_t> g_pools;
1115 extern GlobalStateHolder<vector<DNSDistRuleAction> > g_rulactions;
1116 extern GlobalStateHolder<vector<DNSDistResponseRuleAction> > g_resprulactions;
1117 extern GlobalStateHolder<vector<DNSDistResponseRuleAction> > g_cachehitresprulactions;
1118 extern GlobalStateHolder<vector<DNSDistResponseRuleAction> > g_selfansweredresprulactions;
1119 extern GlobalStateHolder<NetmaskGroup> g_ACL;
1120
1121 extern ComboAddress g_serverControl; // not changed during runtime
1122
1123 extern std::vector<std::tuple<ComboAddress, bool, bool, int, std::string, std::set<int>>> g_locals; // not changed at runtime (we hope XXX)
1124 extern std::vector<shared_ptr<TLSFrontend>> g_tlslocals;
1125 extern std::vector<shared_ptr<DOHFrontend>> g_dohlocals;
1126 extern std::vector<std::unique_ptr<ClientState>> g_frontends;
1127 extern bool g_truncateTC;
1128 extern bool g_fixupCase;
1129 extern int g_tcpRecvTimeout;
1130 extern int g_tcpSendTimeout;
1131 extern int g_udpTimeout;
1132 extern uint16_t g_maxOutstanding;
1133 extern std::atomic<bool> g_configurationDone;
1134 extern uint64_t g_maxTCPClientThreads;
1135 extern uint64_t g_maxTCPQueuedConnections;
1136 extern size_t g_maxTCPQueriesPerConn;
1137 extern size_t g_maxTCPConnectionDuration;
1138 extern size_t g_maxTCPConnectionsPerClient;
1139 extern std::atomic<uint16_t> g_cacheCleaningDelay;
1140 extern std::atomic<uint16_t> g_cacheCleaningPercentage;
1141 extern bool g_verboseHealthChecks;
1142 extern uint32_t g_staleCacheEntriesTTL;
1143 extern bool g_apiReadWrite;
1144 extern std::string g_apiConfigDirectory;
1145 extern bool g_servFailOnNoPolicy;
1146 extern uint32_t g_hashperturb;
1147 extern bool g_useTCPSinglePipe;
1148 extern uint16_t g_downstreamTCPCleanupInterval;
1149 extern size_t g_udpVectorSize;
1150 extern bool g_preserveTrailingData;
1151 extern bool g_allowEmptyResponse;
1152 extern bool g_roundrobinFailOnNoServer;
1153
1154 #ifdef HAVE_EBPF
1155 extern shared_ptr<BPFFilter> g_defaultBPFFilter;
1156 extern std::vector<std::shared_ptr<DynBPFFilter> > g_dynBPFFilters;
1157 #endif /* HAVE_EBPF */
1158
1159 struct LocalHolders
1160 {
1161   LocalHolders(): acl(g_ACL.getLocal()), policy(g_policy.getLocal()), rulactions(g_rulactions.getLocal()), cacheHitRespRulactions(g_cachehitresprulactions.getLocal()), selfAnsweredRespRulactions(g_selfansweredresprulactions.getLocal()), servers(g_dstates.getLocal()), dynNMGBlock(g_dynblockNMG.getLocal()), dynSMTBlock(g_dynblockSMT.getLocal()), pools(g_pools.getLocal())
1162   {
1163   }
1164
1165   LocalStateHolder<NetmaskGroup> acl;
1166   LocalStateHolder<ServerPolicy> policy;
1167   LocalStateHolder<vector<DNSDistRuleAction> > rulactions;
1168   LocalStateHolder<vector<DNSDistResponseRuleAction> > cacheHitRespRulactions;
1169   LocalStateHolder<vector<DNSDistResponseRuleAction> > selfAnsweredRespRulactions;
1170   LocalStateHolder<servers_t> servers;
1171   LocalStateHolder<NetmaskTree<DynBlock> > dynNMGBlock;
1172   LocalStateHolder<SuffixMatchTree<DynBlock> > dynSMTBlock;
1173   LocalStateHolder<pools_t> pools;
1174 };
1175
1176 struct dnsheader;
1177
1178 void controlThread(int fd, ComboAddress local);
1179 vector<std::function<void(void)>> setupLua(bool client, const std::string& config);
1180 std::shared_ptr<ServerPool> getPool(const pools_t& pools, const std::string& poolName);
1181 std::shared_ptr<ServerPool> createPoolIfNotExists(pools_t& pools, const string& poolName);
1182 NumberedServerVector getDownstreamCandidates(const pools_t& pools, const std::string& poolName);
1183
1184 std::shared_ptr<DownstreamState> firstAvailable(const NumberedServerVector& servers, const DNSQuestion* dq);
1185
1186 std::shared_ptr<DownstreamState> leastOutstanding(const NumberedServerVector& servers, const DNSQuestion* dq);
1187 std::shared_ptr<DownstreamState> wrandom(const NumberedServerVector& servers, const DNSQuestion* dq);
1188 std::shared_ptr<DownstreamState> whashed(const NumberedServerVector& servers, const DNSQuestion* dq);
1189 std::shared_ptr<DownstreamState> chashed(const NumberedServerVector& servers, const DNSQuestion* dq);
1190 std::shared_ptr<DownstreamState> roundrobin(const NumberedServerVector& servers, const DNSQuestion* dq);
1191
1192 struct WebserverConfig
1193 {
1194   std::string password;
1195   std::string apiKey;
1196   boost::optional<std::map<std::string, std::string> > customHeaders;
1197   std::mutex lock;
1198 };
1199
1200 void setWebserverAPIKey(const boost::optional<std::string> apiKey);
1201 void setWebserverPassword(const std::string& password);
1202 void setWebserverCustomHeaders(const boost::optional<std::map<std::string, std::string> > customHeaders);
1203
1204 void dnsdistWebserverThread(int sock, const ComboAddress& local);
1205 void tcpAcceptorThread(void* p);
1206 #ifdef HAVE_DNS_OVER_HTTPS
1207 void dohThread(ClientState* cs);
1208 #endif /* HAVE_DNS_OVER_HTTPS */
1209
1210 void setLuaNoSideEffect(); // if nothing has been declared, set that there are no side effects
1211 void setLuaSideEffect();   // set to report a side effect, cancelling all _no_ side effect calls
1212 bool getLuaNoSideEffect(); // set if there were only explicit declarations of _no_ side effect
1213 void resetLuaSideEffect(); // reset to indeterminate state
1214
1215 bool responseContentMatches(const char* response, const uint16_t responseLen, const DNSName& qname, const uint16_t qtype, const uint16_t qclass, const ComboAddress& remote, unsigned int& consumed);
1216 bool processResponse(char** response, uint16_t* responseLen, size_t* responseSize, LocalStateHolder<vector<DNSDistResponseRuleAction> >& localRespRulactions, DNSResponse& dr, size_t addRoom, std::vector<uint8_t>& rewrittenResponse, bool muted);
1217 bool processRulesResult(const DNSAction::Action& action, DNSQuestion& dq, std::string& ruleresult, bool& drop);
1218
1219 bool checkQueryHeaders(const struct dnsheader* dh);
1220
1221 extern std::vector<std::shared_ptr<DNSCryptContext>> g_dnsCryptLocals;
1222 int handleDNSCryptQuery(char* packet, uint16_t len, std::shared_ptr<DNSCryptQuery> query, uint16_t* decryptedQueryLen, bool tcp, time_t now, std::vector<uint8_t>& response);
1223 boost::optional<std::vector<uint8_t>> checkDNSCryptQuery(const ClientState& cs, const char* query, uint16_t& len, std::shared_ptr<DNSCryptQuery>& dnsCryptQuery, time_t now, bool tcp);
1224
1225 bool addXPF(DNSQuestion& dq, uint16_t optionCode);
1226
1227 uint16_t getRandomDNSID();
1228
1229 #include "dnsdist-snmp.hh"
1230
1231 extern bool g_snmpEnabled;
1232 extern bool g_snmpTrapsEnabled;
1233 extern DNSDistSNMPAgent* g_snmpAgent;
1234 extern bool g_addEDNSToSelfGeneratedResponses;
1235
1236 extern std::set<std::string> g_capabilitiesToRetain;
1237
1238 static const size_t s_udpIncomingBufferSize{1500};
1239
1240 enum class ProcessQueryResult { Drop, SendAnswer, PassToBackend };
1241 ProcessQueryResult processQuery(DNSQuestion& dq, ClientState& cs, LocalHolders& holders, std::shared_ptr<DownstreamState>& selectedBackend);
1242
1243 DNSResponse makeDNSResponseFromIDState(IDState& ids, struct dnsheader* dh, size_t bufferSize, uint16_t responseLen, bool isTCP);
1244 void setIDStateFromDNSQuestion(IDState& ids, DNSQuestion& dq, DNSName&& qname);
1245
1246 int pickBackendSocketForSending(std::shared_ptr<DownstreamState>& state);
1247 ssize_t udpClientSendRequestToBackend(const std::shared_ptr<DownstreamState>& ss, const int sd, const char* request, const size_t requestLen, bool healthCheck=false);