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   std::atomic<uint64_t> tlsUnknownTicketKey{0}; // A TLS ticket has been presented but we don't have the associated key (might have expired)
 689   std::atomic<uint64_t> tlsInactiveTicketKey{0}; // A TLS ticket has been successfully resumed but the key is no longer active, we should issue a new one
 690   std::atomic<uint64_t> tls10queries{0};   // valid DNS queries received via TLSv1.0
 691   std::atomic<uint64_t> tls11queries{0};   // valid DNS queries received via TLSv1.1
 692   std::atomic<uint64_t> tls12queries{0};   // valid DNS queries received via TLSv1.2
 693   std::atomic<uint64_t> tls13queries{0};   // valid DNS queries received via TLSv1.3
 694   std::atomic<uint64_t> tlsUnknownqueries{0};   // valid DNS queries received via unknown TLS version
 695   std::atomic<double> tcpAvgQueriesPerConnection{0.0};
 696   /* in ms */
 697   std::atomic<double> tcpAvgConnectionDuration{0.0};
 698   int udpFD{-1};
 699   int tcpFD{-1};
 700   int fastOpenQueueSize{0};
 701   bool muted{false};
 702   bool tcp;
 703   bool reuseport;
 704   bool ready{false};
 705
 706   int getSocket() const
 707   {
 708     return udpFD != -1 ? udpFD : tcpFD;
 709   }
 710
 711   bool isUDP() const
 712   {
 713     return udpFD != -1;
 714   }
 715
 716   bool isTCP() const
 717   {
 718     return udpFD == -1;
 719   }
 720
 721   std::string getType() const
 722   {
 723     std::string result = udpFD != -1 ? "UDP" : "TCP";
 724
 725     if (dohFrontend) {
 726       result += " (DNS over HTTPS)";
 727     }
 728     else if (tlsFrontend) {
 729       result += " (DNS over TLS)";
 730     }
 731     else if (dnscryptCtx) {
 732       result += " (DNSCrypt)";
 733     }
 734
 735     return result;
 736   }
 737
 738 #ifdef HAVE_EBPF
 739   shared_ptr<BPFFilter> d_filter;
 740
 741   void detachFilter()
 742   {
 743     if (d_filter) {
 744       d_filter->removeSocket(getSocket());
 745       d_filter = nullptr;
 746     }
 747   }
 748
 749   void attachFilter(shared_ptr<BPFFilter> bpf)
 750   {
 751     detachFilter();
 752
 753     bpf->addSocket(getSocket());
 754     d_filter = bpf;
 755   }
 756 #endif /* HAVE_EBPF */
 757
 758   void updateTCPMetrics(size_t nbQueries, uint64_t durationMs)
 759   {
 760     tcpAvgQueriesPerConnection = (99.0 * tcpAvgQueriesPerConnection / 100.0) + (nbQueries / 100.0);
 761     tcpAvgConnectionDuration = (99.0 * tcpAvgConnectionDuration / 100.0) + (durationMs / 100.0);
 762   }
 763 };
 764
 765 class TCPClientCollection {
 766   std::vector<int> d_tcpclientthreads;
 767   std::atomic<uint64_t> d_numthreads{0};
 768   std::atomic<uint64_t> d_pos{0};
 769   std::atomic<uint64_t> d_queued{0};
 770   const uint64_t d_maxthreads{0};
 771   std::mutex d_mutex;
 772   int d_singlePipe[2];
 773   const bool d_useSinglePipe;
 774 public:
 775
 776   TCPClientCollection(size_t maxThreads, bool useSinglePipe=false): d_maxthreads(maxThreads), d_singlePipe{-1,-1}, d_useSinglePipe(useSinglePipe)
 777
 778   {
 779     d_tcpclientthreads.reserve(maxThreads);
 780
 781     if (d_useSinglePipe) {
 782       if (pipe(d_singlePipe) < 0) {
 783         int err = errno;
 784         throw std::runtime_error("Error creating the TCP single communication pipe: " + stringerror(err));
 785       }
 786
 787       if (!setNonBlocking(d_singlePipe[0])) {
 788         int err = errno;
 789         close(d_singlePipe[0]);
 790         close(d_singlePipe[1]);
 791         throw std::runtime_error("Error setting the TCP single communication pipe non-blocking: " + stringerror(err));
 792       }
 793
 794       if (!setNonBlocking(d_singlePipe[1])) {
 795         int err = errno;
 796         close(d_singlePipe[0]);
 797         close(d_singlePipe[1]);
 798         throw std::runtime_error("Error setting the TCP single communication pipe non-blocking: " + stringerror(err));
 799       }
 800     }
 801   }
 802   int getThread()
 803   {
 804     uint64_t pos = d_pos++;
 805     ++d_queued;
 806     return d_tcpclientthreads[pos % d_numthreads];
 807   }
 808   bool hasReachedMaxThreads() const
 809   {
 810     return d_numthreads >= d_maxthreads;
 811   }
 812   uint64_t getThreadsCount() const
 813   {
 814     return d_numthreads;
 815   }
 816   uint64_t getQueuedCount() const
 817   {
 818     return d_queued;
 819   }
 820   void decrementQueuedCount()
 821   {
 822     --d_queued;
 823   }
 824   void addTCPClientThread();
 825 };
 826
 827 extern std::unique_ptr<TCPClientCollection> g_tcpclientthreads;
 828
 829 struct DownstreamState
 830 {
 831    typedef std::function<std::tuple<DNSName, uint16_t, uint16_t>(const DNSName&, uint16_t, uint16_t, dnsheader*)> checkfunc_t;
 832
 833   DownstreamState(const ComboAddress& remote_, const ComboAddress& sourceAddr_, unsigned int sourceItf, const std::string& sourceItfName, size_t numberOfSockets);
 834   DownstreamState(const ComboAddress& remote_): DownstreamState(remote_, ComboAddress(), 0, std::string(), 1) {}
 835   ~DownstreamState()
 836   {
 837     for (auto& fd : sockets) {
 838       if (fd >= 0) {
 839         close(fd);
 840         fd = -1;
 841       }
 842     }
 843   }
 844   boost::uuids::uuid id;
 845   std::set<unsigned int> hashes;
 846   mutable pthread_rwlock_t d_lock;
 847   std::vector<int> sockets;
 848   const std::string sourceItfName;
 849   std::mutex socketsLock;
 850   std::mutex connectLock;
 851   std::unique_ptr<FDMultiplexer> mplexer{nullptr};
 852   std::thread tid;
 853   const ComboAddress remote;
 854   QPSLimiter qps;
 855   vector<IDState> idStates;
 856   const ComboAddress sourceAddr;
 857   checkfunc_t checkFunction;
 858   DNSName checkName{"a.root-servers.net."};
 859   QType checkType{QType::A};
 860   uint16_t checkClass{QClass::IN};
 861   std::atomic<uint64_t> idOffset{0};
 862   std::atomic<uint64_t> sendErrors{0};
 863   std::atomic<uint64_t> outstanding{0};
 864   std::atomic<uint64_t> reuseds{0};
 865   std::atomic<uint64_t> queries{0};
 866   std::atomic<uint64_t> responses{0};
 867   struct {
 868     std::atomic<uint64_t> sendErrors{0};
 869     std::atomic<uint64_t> reuseds{0};
 870     std::atomic<uint64_t> queries{0};
 871   } prev;
 872   std::atomic<uint64_t> tcpDiedSendingQuery{0};
 873   std::atomic<uint64_t> tcpDiedReadingResponse{0};
 874   std::atomic<uint64_t> tcpGaveUp{0};
 875   std::atomic<uint64_t> tcpReadTimeouts{0};
 876   std::atomic<uint64_t> tcpWriteTimeouts{0};
 877   std::atomic<uint64_t> tcpCurrentConnections{0};
 878   std::atomic<double> tcpAvgQueriesPerConnection{0.0};
 879   /* in ms */
 880   std::atomic<double> tcpAvgConnectionDuration{0.0};
 881   string name;
 882   size_t socketsOffset{0};
 883   double queryLoad{0.0};
 884   double dropRate{0.0};
 885   double latencyUsec{0.0};
 886   int order{1};
 887   int weight{1};
 888   int tcpConnectTimeout{5};
 889   int tcpRecvTimeout{30};
 890   int tcpSendTimeout{30};
 891   unsigned int checkInterval{1};
 892   unsigned int lastCheck{0};
 893   const unsigned int sourceItf{0};
 894   uint16_t retries{5};
 895   uint16_t xpfRRCode{0};
 896   uint16_t checkTimeout{1000}; /* in milliseconds */
 897   uint8_t currentCheckFailures{0};
 898   uint8_t consecutiveSuccessfulChecks{0};
 899   uint8_t maxCheckFailures{1};
 900   uint8_t minRiseSuccesses{1};
 901   StopWatch sw;
 902   set<string> pools;
 903   enum class Availability { Up, Down, Auto} availability{Availability::Auto};
 904   bool mustResolve{false};
 905   bool upStatus{false};
 906   bool useECS{false};
 907   bool setCD{false};
 908   bool disableZeroScope{false};
 909   std::atomic<bool> connected{false};
 910   std::atomic_flag threadStarted;
 911   bool tcpFastOpen{false};
 912   bool ipBindAddrNoPort{true};
 913
 914   bool isUp() const
 915   {
 916     if(availability == Availability::Down)
 917       return false;
 918     if(availability == Availability::Up)
 919       return true;
 920     return upStatus;
 921   }
 922   void setUp() { availability = Availability::Up; }
 923   void setDown() { availability = Availability::Down; }
 924   void setAuto() { availability = Availability::Auto; }
 925   string getName() const {
 926     if (name.empty()) {
 927       return remote.toStringWithPort();
 928     }
 929     return name;
 930   }
 931   string getNameWithAddr() const {
 932     if (name.empty()) {
 933       return remote.toStringWithPort();
 934     }
 935     return name + " (" + remote.toStringWithPort()+ ")";
 936   }
 937   string getStatus() const
 938   {
 939     string status;
 940     if(availability == DownstreamState::Availability::Up)
 941       status = "UP";
 942     else if(availability == DownstreamState::Availability::Down)
 943       status = "DOWN";
 944     else
 945       status = (upStatus ? "up" : "down");
 946     return status;
 947   }
 948   bool reconnect();
 949   void hash();
 950   void setId(const boost::uuids::uuid& newId);
 951   void setWeight(int newWeight);
 952
 953   void updateTCPMetrics(size_t nbQueries, uint64_t durationMs)
 954   {
 955     tcpAvgQueriesPerConnection = (99.0 * tcpAvgQueriesPerConnection / 100.0) + (nbQueries / 100.0);
 956     tcpAvgConnectionDuration = (99.0 * tcpAvgConnectionDuration / 100.0) + (durationMs / 100.0);
 957   }
 958 };
 959 using servers_t =vector<std::shared_ptr<DownstreamState>>;
 960
 961 template <class T> using NumberedVector = std::vector<std::pair<unsigned int, T> >;
 962
 963 void responderThread(std::shared_ptr<DownstreamState> state);
 964 extern std::mutex g_luamutex;
 965 extern LuaContext g_lua;
 966 extern std::string g_outputBuffer; // locking for this is ok, as locked by g_luamutex
 967
 968 class DNSRule
 969 {
 970 public:
 971   virtual ~DNSRule ()
 972   {
 973   }
 974   virtual bool matches(const DNSQuestion* dq) const =0;
 975   virtual string toString() const = 0;
 976   mutable std::atomic<uint64_t> d_matches{0};
 977 };
 978
 979 using NumberedServerVector = NumberedVector<shared_ptr<DownstreamState>>;
 980 typedef std::function<shared_ptr<DownstreamState>(const NumberedServerVector& servers, const DNSQuestion*)> policyfunc_t;
 981
 982 struct ServerPolicy
 983 {
 984   string name;
 985   policyfunc_t policy;
 986   bool isLua;
 987   std::string toString() const {
 988     return string("ServerPolicy") + (isLua ? " (Lua)" : "") + " \"" + name + "\"";
 989   }
 990 };
 991
 992 struct ServerPool
 993 {
 994   ServerPool()
 995   {
 996     pthread_rwlock_init(&d_lock, nullptr);
 997   }
 998
 999   const std::shared_ptr<DNSDistPacketCache> getCache() const { return packetCache; };
1000
1001   bool getECS() const
1002   {
1003     return d_useECS;
1004   }
1005
1006   void setECS(bool useECS)
1007   {
1008     d_useECS = useECS;
1009   }
1010
1011   std::shared_ptr<DNSDistPacketCache> packetCache{nullptr};
1012   std::shared_ptr<ServerPolicy> policy{nullptr};
1013
1014   size_t countServers(bool upOnly)
1015   {
1016     size_t count = 0;
1017     ReadLock rl(&d_lock);
1018     for (const auto& server : d_servers) {
1019       if (!upOnly || std::get<1>(server)->isUp() ) {
1020         count++;
1021       }
1022     }
1023     return count;
1024   }
1025
1026   NumberedVector<shared_ptr<DownstreamState>> getServers()
1027   {
1028     NumberedVector<shared_ptr<DownstreamState>> result;
1029     {
1030       ReadLock rl(&d_lock);
1031       result = d_servers;
1032     }
1033     return result;
1034   }
1035
1036   void addServer(shared_ptr<DownstreamState>& server)
1037   {
1038     WriteLock wl(&d_lock);
1039     unsigned int count = (unsigned int) d_servers.size();
1040     d_servers.push_back(make_pair(++count, server));
1041     /* we need to reorder based on the server 'order' */
1042     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) {
1043       return a.second->order < b.second->order;
1044     });
1045     /* and now we need to renumber for Lua (custom policies) */
1046     size_t idx = 1;
1047     for (auto& serv : d_servers) {
1048       serv.first = idx++;
1049     }
1050   }
1051
1052   void removeServer(shared_ptr<DownstreamState>& server)
1053   {
1054     WriteLock wl(&d_lock);
1055     size_t idx = 1;
1056     bool found = false;
1057     for (auto it = d_servers.begin(); it != d_servers.end();) {
1058       if (found) {
1059         /* we need to renumber the servers placed
1060            after the removed one, for Lua (custom policies) */
1061         it->first = idx++;
1062         it++;
1063       }
1064       else if (it->second == server) {
1065         it = d_servers.erase(it);
1066         found = true;
1067       } else {
1068         idx++;
1069         it++;
1070       }
1071     }
1072   }
1073
1074 private:
1075   NumberedVector<shared_ptr<DownstreamState>> d_servers;
1076   pthread_rwlock_t d_lock;
1077   bool d_useECS{false};
1078 };
1079 using pools_t=map<std::string,std::shared_ptr<ServerPool>>;
1080 void setPoolPolicy(pools_t& pools, const string& poolName, std::shared_ptr<ServerPolicy> policy);
1081 void addServerToPool(pools_t& pools, const string& poolName, std::shared_ptr<DownstreamState> server);
1082 void removeServerFromPool(pools_t& pools, const string& poolName, std::shared_ptr<DownstreamState> server);
1083
1084 struct CarbonConfig
1085 {
1086   ComboAddress server;
1087   std::string namespace_name;
1088   std::string ourname;
1089   std::string instance_name;
1090   unsigned int interval;
1091 };
1092
1093 enum ednsHeaderFlags {
1094   EDNS_HEADER_FLAG_NONE = 0,
1095   EDNS_HEADER_FLAG_DO = 32768
1096 };
1097
1098 struct DNSDistRuleAction
1099 {
1100   std::shared_ptr<DNSRule> d_rule;
1101   std::shared_ptr<DNSAction> d_action;
1102   boost::uuids::uuid d_id;
1103   uint64_t d_creationOrder;
1104 };
1105
1106 struct DNSDistResponseRuleAction
1107 {
1108   std::shared_ptr<DNSRule> d_rule;
1109   std::shared_ptr<DNSResponseAction> d_action;
1110   boost::uuids::uuid d_id;
1111   uint64_t d_creationOrder;
1112 };
1113
1114 extern GlobalStateHolder<SuffixMatchTree<DynBlock>> g_dynblockSMT;
1115 extern DNSAction::Action g_dynBlockAction;
1116
1117 extern GlobalStateHolder<vector<CarbonConfig> > g_carbon;
1118 extern GlobalStateHolder<ServerPolicy> g_policy;
1119 extern GlobalStateHolder<servers_t> g_dstates;
1120 extern GlobalStateHolder<pools_t> g_pools;
1121 extern GlobalStateHolder<vector<DNSDistRuleAction> > g_rulactions;
1122 extern GlobalStateHolder<vector<DNSDistResponseRuleAction> > g_resprulactions;
1123 extern GlobalStateHolder<vector<DNSDistResponseRuleAction> > g_cachehitresprulactions;
1124 extern GlobalStateHolder<vector<DNSDistResponseRuleAction> > g_selfansweredresprulactions;
1125 extern GlobalStateHolder<NetmaskGroup> g_ACL;
1126
1127 extern ComboAddress g_serverControl; // not changed during runtime
1128
1129 extern std::vector<std::tuple<ComboAddress, bool, bool, int, std::string, std::set<int>>> g_locals; // not changed at runtime (we hope XXX)
1130 extern std::vector<shared_ptr<TLSFrontend>> g_tlslocals;
1131 extern std::vector<shared_ptr<DOHFrontend>> g_dohlocals;
1132 extern std::vector<std::unique_ptr<ClientState>> g_frontends;
1133 extern bool g_truncateTC;
1134 extern bool g_fixupCase;
1135 extern int g_tcpRecvTimeout;
1136 extern int g_tcpSendTimeout;
1137 extern int g_udpTimeout;
1138 extern uint16_t g_maxOutstanding;
1139 extern std::atomic<bool> g_configurationDone;
1140 extern uint64_t g_maxTCPClientThreads;
1141 extern uint64_t g_maxTCPQueuedConnections;
1142 extern size_t g_maxTCPQueriesPerConn;
1143 extern size_t g_maxTCPConnectionDuration;
1144 extern size_t g_maxTCPConnectionsPerClient;
1145 extern std::atomic<uint16_t> g_cacheCleaningDelay;
1146 extern std::atomic<uint16_t> g_cacheCleaningPercentage;
1147 extern bool g_verboseHealthChecks;
1148 extern uint32_t g_staleCacheEntriesTTL;
1149 extern bool g_apiReadWrite;
1150 extern std::string g_apiConfigDirectory;
1151 extern bool g_servFailOnNoPolicy;
1152 extern uint32_t g_hashperturb;
1153 extern bool g_useTCPSinglePipe;
1154 extern uint16_t g_downstreamTCPCleanupInterval;
1155 extern size_t g_udpVectorSize;
1156 extern bool g_preserveTrailingData;
1157 extern bool g_allowEmptyResponse;
1158 extern bool g_roundrobinFailOnNoServer;
1159
1160 #ifdef HAVE_EBPF
1161 extern shared_ptr<BPFFilter> g_defaultBPFFilter;
1162 extern std::vector<std::shared_ptr<DynBPFFilter> > g_dynBPFFilters;
1163 #endif /* HAVE_EBPF */
1164
1165 struct LocalHolders
1166 {
1167   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())
1168   {
1169   }
1170
1171   LocalStateHolder<NetmaskGroup> acl;
1172   LocalStateHolder<ServerPolicy> policy;
1173   LocalStateHolder<vector<DNSDistRuleAction> > rulactions;
1174   LocalStateHolder<vector<DNSDistResponseRuleAction> > cacheHitRespRulactions;
1175   LocalStateHolder<vector<DNSDistResponseRuleAction> > selfAnsweredRespRulactions;
1176   LocalStateHolder<servers_t> servers;
1177   LocalStateHolder<NetmaskTree<DynBlock> > dynNMGBlock;
1178   LocalStateHolder<SuffixMatchTree<DynBlock> > dynSMTBlock;
1179   LocalStateHolder<pools_t> pools;
1180 };
1181
1182 struct dnsheader;
1183
1184 void controlThread(int fd, ComboAddress local);
1185 vector<std::function<void(void)>> setupLua(bool client, const std::string& config);
1186 std::shared_ptr<ServerPool> getPool(const pools_t& pools, const std::string& poolName);
1187 std::shared_ptr<ServerPool> createPoolIfNotExists(pools_t& pools, const string& poolName);
1188 NumberedServerVector getDownstreamCandidates(const pools_t& pools, const std::string& poolName);
1189
1190 std::shared_ptr<DownstreamState> firstAvailable(const NumberedServerVector& servers, const DNSQuestion* dq);
1191
1192 std::shared_ptr<DownstreamState> leastOutstanding(const NumberedServerVector& servers, const DNSQuestion* dq);
1193 std::shared_ptr<DownstreamState> wrandom(const NumberedServerVector& servers, const DNSQuestion* dq);
1194 std::shared_ptr<DownstreamState> whashed(const NumberedServerVector& servers, const DNSQuestion* dq);
1195 std::shared_ptr<DownstreamState> chashed(const NumberedServerVector& servers, const DNSQuestion* dq);
1196 std::shared_ptr<DownstreamState> roundrobin(const NumberedServerVector& servers, const DNSQuestion* dq);
1197
1198 struct WebserverConfig
1199 {
1200   std::string password;
1201   std::string apiKey;
1202   boost::optional<std::map<std::string, std::string> > customHeaders;
1203   std::mutex lock;
1204 };
1205
1206 void setWebserverAPIKey(const boost::optional<std::string> apiKey);
1207 void setWebserverPassword(const std::string& password);
1208 void setWebserverCustomHeaders(const boost::optional<std::map<std::string, std::string> > customHeaders);
1209
1210 void dnsdistWebserverThread(int sock, const ComboAddress& local);
1211 void tcpAcceptorThread(void* p);
1212 #ifdef HAVE_DNS_OVER_HTTPS
1213 void dohThread(ClientState* cs);
1214 #endif /* HAVE_DNS_OVER_HTTPS */
1215
1216 void setLuaNoSideEffect(); // if nothing has been declared, set that there are no side effects
1217 void setLuaSideEffect();   // set to report a side effect, cancelling all _no_ side effect calls
1218 bool getLuaNoSideEffect(); // set if there were only explicit declarations of _no_ side effect
1219 void resetLuaSideEffect(); // reset to indeterminate state
1220
1221 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);
1222 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);
1223 bool processRulesResult(const DNSAction::Action& action, DNSQuestion& dq, std::string& ruleresult, bool& drop);
1224
1225 bool checkQueryHeaders(const struct dnsheader* dh);
1226
1227 extern std::vector<std::shared_ptr<DNSCryptContext>> g_dnsCryptLocals;
1228 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);
1229 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);
1230
1231 bool addXPF(DNSQuestion& dq, uint16_t optionCode);
1232
1233 uint16_t getRandomDNSID();
1234
1235 #include "dnsdist-snmp.hh"
1236
1237 extern bool g_snmpEnabled;
1238 extern bool g_snmpTrapsEnabled;
1239 extern DNSDistSNMPAgent* g_snmpAgent;
1240 extern bool g_addEDNSToSelfGeneratedResponses;
1241
1242 extern std::set<std::string> g_capabilitiesToRetain;
1243
1244 static const size_t s_udpIncomingBufferSize{1500};
1245
1246 enum class ProcessQueryResult { Drop, SendAnswer, PassToBackend };
1247 ProcessQueryResult processQuery(DNSQuestion& dq, ClientState& cs, LocalHolders& holders, std::shared_ptr<DownstreamState>& selectedBackend);
1248
1249 DNSResponse makeDNSResponseFromIDState(IDState& ids, struct dnsheader* dh, size_t bufferSize, uint16_t responseLen, bool isTCP);
1250 void setIDStateFromDNSQuestion(IDState& ids, DNSQuestion& dq, DNSName&& qname);
1251
1252 int pickBackendSocketForSending(std::shared_ptr<DownstreamState>& state);
1253 ssize_t udpClientSendRequestToBackend(const std::shared_ptr<DownstreamState>& ss, const int sd, const char* request, const size_t requestLen, bool healthCheck=false);