pdns/common_startup.cc

   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 #ifdef HAVE_CONFIG_H
  23 #include "config.h"
  24 #endif
  25 #include "common_startup.hh"
  26 #include "ws-auth.hh"
  27 #include "secpoll-auth.hh"
  28 #include <sys/time.h>
  29 #include <sys/resource.h>
  30 #include "dynhandler.hh"
  31 #include "dnsseckeeper.hh"
  32
  33 #ifdef HAVE_SYSTEMD
  34 #include <systemd/sd-daemon.h>
  35 #endif
  36
  37 bool g_anyToTcp;
  38 bool g_8bitDNS;
  39 typedef Distributor<DNSPacket,DNSPacket,PacketHandler> DNSDistributor;
  40
  41 ArgvMap theArg;
  42 StatBag S;  //!< Statistics are gathered across PDNS via the StatBag class S
  43 AuthPacketCache PC; //!< This is the main PacketCache, shared across all threads
  44 AuthQueryCache QC;
  45 DNSProxy *DP;
  46 DynListener *dl;
  47 CommunicatorClass Communicator;
  48 shared_ptr<UDPNameserver> N;
  49 int avg_latency;
  50 TCPNameserver *TN;
  51 static vector<DNSDistributor*> g_distributors;
  52 vector<std::shared_ptr<UDPNameserver> > g_udpReceivers;
  53
  54 ArgvMap &arg()
  55 {
  56   return theArg;
  57 }
  58
  59 void declareArguments()
  60 {
  61   ::arg().set("local-port","The port on which we listen")="53";
  62   ::arg().setSwitch("dnsupdate","Enable/Disable DNS update (RFC2136) support. Default is no.")="no";
  63   ::arg().setSwitch("write-pid","Write a PID file")="yes";
  64   ::arg().set("allow-dnsupdate-from","A global setting to allow DNS updates from these IP ranges.")="127.0.0.0/8,::1";
  65   ::arg().set("allow-unsigned-notify","Allow unsigned notifications for TSIG secured domains")="yes"; //FIXME: change to 'no' later
  66   ::arg().set("allow-unsigned-supermaster", "Allow supermasters to create zones without TSIG signed NOTIFY")="yes";
  67   ::arg().setSwitch("forward-dnsupdate","A global setting to allow DNS update packages that are for a Slave domain, to be forwarded to the master.")="yes";
  68   ::arg().setSwitch("log-dns-details","If PDNS should log DNS non-erroneous details")="no";
  69   ::arg().setSwitch("log-dns-queries","If PDNS should log all incoming DNS queries")="no";
  70   ::arg().set("local-address","Local IP addresses to which we bind")="0.0.0.0";
  71   ::arg().setSwitch("local-address-nonexist-fail","Fail to start if one or more of the local-address's do not exist on this server")="yes";
  72   ::arg().setSwitch("non-local-bind", "Enable binding to non-local addresses by using FREEBIND / BINDANY socket options")="no";
  73   ::arg().set("local-ipv6","Local IP address to which we bind")="::";
  74   ::arg().setSwitch("reuseport","Enable higher performance on compliant kernels by using SO_REUSEPORT allowing each receiver thread to open its own socket")="no";
  75   ::arg().setSwitch("local-ipv6-nonexist-fail","Fail to start if one or more of the local-ipv6 addresses do not exist on this server")="yes";
  76   ::arg().set("query-local-address","Source IP address for sending queries")="0.0.0.0";
  77   ::arg().set("query-local-address6","Source IPv6 address for sending queries")="::";
  78   ::arg().set("overload-queue-length","Maximum queuelength moving to packetcache only")="0";
  79   ::arg().set("max-queue-length","Maximum queuelength before considering situation lost")="5000";
  80
  81   ::arg().set("retrieval-threads", "Number of AXFR-retrieval threads for slave operation")="2";
  82   ::arg().setSwitch("api", "Enable/disable the REST API (including HTTP listener)")="no";
  83   ::arg().set("api-key", "Static pre-shared authentication key for access to the REST API")="";
  84   ::arg().set("api-logfile", "Location of the server logfile (used by the REST API)")="/var/log/pdns.log";
  85   ::arg().setSwitch("api-readonly", "Disallow data modification through the REST API when set")="no";
  86   ::arg().setSwitch("dname-processing", "If we should support DNAME records")="no";
  87
  88   ::arg().setCmd("help","Provide a helpful message");
  89   ::arg().setCmd("version","Output version and compilation date");
  90   ::arg().setCmd("config","Provide configuration file on standard output");
  91   ::arg().setCmd("list-modules","Lists all modules available");
  92   ::arg().setCmd("no-config","Don't parse configuration file");
  93
  94   ::arg().set("version-string","PowerDNS version in packets - full, anonymous, powerdns or custom")="full";
  95   ::arg().set("control-console","Debugging switch - don't use")="no"; // but I know you will!
  96   ::arg().set("loglevel","Amount of logging. Higher is more. Do not set below 3")="4";
  97   ::arg().set("disable-syslog","Disable logging to syslog, useful when running inside a supervisor that logs stdout")="no";
  98   ::arg().set("log-timestamp","Print timestamps in log lines")="yes";
  99   ::arg().set("default-soa-name","name to insert in the SOA record if none set in the backend")="a.misconfigured.powerdns.server";
 100   ::arg().set("default-soa-mail","mail address to insert in the SOA record if none set in the backend")="";
 101   ::arg().set("distributor-threads","Default number of Distributor (backend) threads to start")="3";
 102   ::arg().set("signing-threads","Default number of signer threads to start")="3";
 103   ::arg().set("receiver-threads","Default number of receiver threads to start")="1";
 104   ::arg().set("queue-limit","Maximum number of milliseconds to queue a query")="1500";
 105   ::arg().set("resolver","Use this resolver for ALIAS and the internal stub resolver")="no";
 106   ::arg().set("udp-truncation-threshold", "Maximum UDP response size before we truncate")="1680";
 107   ::arg().set("disable-tcp","Do not listen to TCP queries")="no";
 108
 109   ::arg().set("config-name","Name of this virtual configuration - will rename the binary image")="";
 110
 111   ::arg().set("load-modules","Load this module - supply absolute or relative path")="";
 112   ::arg().set("launch","Which backends to launch and order to query them in")="";
 113   ::arg().setSwitch("disable-axfr","Disable zonetransfers but do allow TCP queries")="no";
 114   ::arg().set("allow-axfr-ips","Allow zonetransfers only to these subnets")="127.0.0.0/8,::1";
 115   ::arg().set("only-notify", "Only send AXFR NOTIFY to these IP addresses or netmasks")="0.0.0.0/0,::/0";
 116   ::arg().set("also-notify", "When notifying a domain, also notify these nameservers")="";
 117   ::arg().set("allow-notify-from","Allow AXFR NOTIFY from these IP ranges. If empty, drop all incoming notifies.")="0.0.0.0/0,::/0";
 118   ::arg().set("slave-cycle-interval","Schedule slave freshness checks once every .. seconds")="60";
 119
 120   ::arg().set("tcp-control-address","If set, PowerDNS can be controlled over TCP on this address")="";
 121   ::arg().set("tcp-control-port","If set, PowerDNS can be controlled over TCP on this address")="53000";
 122   ::arg().set("tcp-control-secret","If set, PowerDNS can be controlled over TCP after passing this secret")="";
 123   ::arg().set("tcp-control-range","If set, remote control of PowerDNS is possible over these networks only")="127.0.0.0/8, 10.0.0.0/8, 192.168.0.0/16, 172.16.0.0/12, ::1/128, fe80::/10";
 124
 125   ::arg().setSwitch("slave","Act as a slave")="no";
 126   ::arg().setSwitch("master","Act as a master")="no";
 127   ::arg().setSwitch("disable-axfr-rectify","Disable the rectify step during an outgoing AXFR. Only required for regression testing.")="no";
 128   ::arg().setSwitch("guardian","Run within a guardian process")="no";
 129   ::arg().setSwitch("prevent-self-notification","Don't send notifications to what we think is ourself")="yes";
 130   ::arg().setSwitch("any-to-tcp","Answer ANY queries with tc=1, shunting to TCP")="yes";
 131   ::arg().setSwitch("edns-subnet-processing","If we should act on EDNS Subnet options")="no";
 132
 133   ::arg().setSwitch("webserver","Start a webserver for monitoring (api=yes also enables the HTTP listener)")="no";
 134   ::arg().setSwitch("webserver-print-arguments","If the webserver should print arguments")="no";
 135   ::arg().set("webserver-address","IP Address of webserver/API to listen on")="127.0.0.1";
 136   ::arg().set("webserver-port","Port of webserver/API to listen on")="8081";
 137   ::arg().set("webserver-password","Password required for accessing the webserver")="";
 138   ::arg().set("webserver-allow-from","Webserver/API access is only allowed from these subnets")="127.0.0.1,::1";
 139
 140   ::arg().setSwitch("out-of-zone-additional-processing","Do out of zone additional processing")="yes";
 141   ::arg().setSwitch("do-ipv6-additional-processing", "Do AAAA additional processing")="yes";
 142   ::arg().setSwitch("query-logging","Hint backends that queries should be logged")="no";
 143
 144   ::arg().set("carbon-ourname", "If set, overrides our reported hostname for carbon stats")="";
 145   ::arg().set("carbon-server", "If set, send metrics in carbon (graphite) format to this server IP address")="";
 146   ::arg().set("carbon-interval", "Number of seconds between carbon (graphite) updates")="30";
 147
 148   ::arg().set("cache-ttl","Seconds to store packets in the PacketCache")="20";
 149   ::arg().set("negquery-cache-ttl","Seconds to store negative query results in the QueryCache")="60";
 150   ::arg().set("query-cache-ttl","Seconds to store query results in the QueryCache")="20";
 151   ::arg().set("soa-minimum-ttl","Default SOA minimum ttl")="3600";
 152   ::arg().set("server-id", "Returned when queried for 'id.server' TXT or NSID, defaults to hostname - disabled or custom")="";
 153   ::arg().set("soa-refresh-default","Default SOA refresh")="10800";
 154   ::arg().set("soa-retry-default","Default SOA retry")="3600";
 155   ::arg().set("soa-expire-default","Default SOA expire")="604800";
 156   ::arg().set("default-soa-edit","Default SOA-EDIT value")="";
 157   ::arg().set("default-soa-edit-signed","Default SOA-EDIT value for signed zones")="";
 158   ::arg().set("dnssec-key-cache-ttl","Seconds to cache DNSSEC keys from the database")="30";
 159   ::arg().set("domain-metadata-cache-ttl","Seconds to cache domain metadata from the database")="60";
 160
 161   ::arg().set("trusted-notification-proxy", "IP address of incoming notification proxy")="";
 162   ::arg().set("slave-renotify", "If we should send out notifications for slaved updates")="no";
 163   ::arg().set("forward-notify", "IP addresses to forward received notifications to regardless of master or slave settings")="";
 164
 165   ::arg().set("default-ttl","Seconds a result is valid if not set otherwise")="3600";
 166   ::arg().set("max-tcp-connections","Maximum number of TCP connections")="20";
 167   ::arg().set("max-tcp-connections-per-client","Maximum number of simultaneous TCP connections per client")="0";
 168   ::arg().set("max-tcp-transactions-per-conn")="0";
 169   ::arg().set("max-tcp-connection-duration")="0";
 170   ::arg().set("tcp-idle-timeout")="5";
 171
 172   ::arg().setSwitch("no-shuffle","Set this to prevent random shuffling of answers - for regression testing")="off";
 173
 174   ::arg().set("setuid","If set, change user id to this uid for more security")="";
 175   ::arg().set("setgid","If set, change group id to this gid for more security")="";
 176
 177   ::arg().set("max-cache-entries", "Maximum number of entries in the query cache")="1000000";
 178   ::arg().set("max-packet-cache-entries", "Maximum number of entries in the packet cache")="1000000";
 179   ::arg().set("max-signature-cache-entries", "Maximum number of signatures cache entries")="";
 180   ::arg().set("max-ent-entries", "Maximum number of empty non-terminals in a zone")="100000";
 181   ::arg().set("entropy-source", "If set, read entropy from this file")="/dev/urandom";
 182
 183   ::arg().set("lua-prequery-script", "Lua script with prequery handler (DO NOT USE)")="";
 184   ::arg().set("lua-dnsupdate-policy-script", "Lua script with DNS update policy handler")="";
 185
 186   ::arg().setSwitch("traceback-handler","Enable the traceback handler (Linux only)")="yes";
 187   ::arg().setSwitch("direct-dnskey","Fetch DNSKEY RRs from backend during DNSKEY synthesis")="no";
 188   ::arg().set("default-ksk-algorithm","Default KSK algorithm")="ecdsa256";
 189   ::arg().set("default-ksk-size","Default KSK size (0 means default)")="0";
 190   ::arg().set("default-zsk-algorithm","Default ZSK algorithm")="";
 191   ::arg().set("default-zsk-size","Default ZSK size (0 means default)")="0";
 192   ::arg().set("max-nsec3-iterations","Limit the number of NSEC3 hash iterations")="500"; // RFC5155 10.3
 193
 194   ::arg().set("include-dir","Include *.conf files from this directory");
 195   ::arg().set("security-poll-suffix","Domain name from which to query security update notifications")="secpoll.powerdns.com.";
 196
 197   ::arg().setSwitch("expand-alias", "Expand ALIAS records")="no";
 198   ::arg().setSwitch("outgoing-axfr-expand-alias", "Expand ALIAS records during outgoing AXFR")="no";
 199   ::arg().setSwitch("8bit-dns", "Allow 8bit dns queries")="no";
 200   ::arg().setSwitch("axfr-lower-serial", "Also AXFR a zone from a master with a lower serial")="no";
 201
 202   ::arg().set("lua-axfr-script", "Script to be used to edit incoming AXFRs")="";
 203   ::arg().set("xfr-max-received-mbytes", "Maximum number of megabytes received from an incoming XFR")="100";
 204
 205   ::arg().set("tcp-fast-open", "Enable TCP Fast Open support on the listening sockets, using the supplied numerical value as the queue size")="0";
 206 }
 207
 208 static time_t s_start=time(0);
 209 static uint64_t uptimeOfProcess(const std::string& str)
 210 {
 211   return time(0) - s_start;
 212 }
 213
 214 static uint64_t getSysUserTimeMsec(const std::string& str)
 215 {
 216   struct rusage ru;
 217   getrusage(RUSAGE_SELF, &ru);
 218
 219   if(str=="sys-msec") {
 220     return (ru.ru_stime.tv_sec*1000ULL + ru.ru_stime.tv_usec/1000);
 221   }
 222   else
 223     return (ru.ru_utime.tv_sec*1000ULL + ru.ru_utime.tv_usec/1000);
 224
 225 }
 226
 227 static uint64_t getQCount(const std::string& str)
 228 try
 229 {
 230   int totcount=0;
 231   for(DNSDistributor* d :  g_distributors) {
 232     if(!d)
 233       continue;
 234     totcount += d->getQueueSize();  // this does locking and other things, so don't get smart
 235   }
 236   return totcount;
 237 }
 238 catch(std::exception& e)
 239 {
 240   L<<Logger::Error<<"Had error retrieving queue sizes: "<<e.what()<<endl;
 241   return 0;
 242 }
 243 catch(PDNSException& e)
 244 {
 245   L<<Logger::Error<<"Had error retrieving queue sizes: "<<e.reason<<endl;
 246   return 0;
 247 }
 248
 249 static uint64_t getLatency(const std::string& str)
 250 {
 251   return avg_latency;
 252 }
 253
 254 void declareStats(void)
 255 {
 256   S.declare("udp-queries","Number of UDP queries received");
 257   S.declare("udp-do-queries","Number of UDP queries received with DO bit");
 258   S.declare("udp-answers","Number of answers sent out over UDP");
 259   S.declare("udp-answers-bytes","Total size of answers sent out over UDP");
 260   S.declare("udp4-answers-bytes","Total size of answers sent out over UDPv4");
 261   S.declare("udp6-answers-bytes","Total size of answers sent out over UDPv6");
 262
 263   S.declare("udp4-answers","Number of IPv4 answers sent out over UDP");
 264   S.declare("udp4-queries","Number of IPv4 UDP queries received");
 265   S.declare("udp6-answers","Number of IPv6 answers sent out over UDP");
 266   S.declare("udp6-queries","Number of IPv6 UDP queries received");
 267   S.declare("overload-drops","Queries dropped because backends overloaded");
 268
 269   S.declare("rd-queries", "Number of recursion desired questions");
 270   S.declare("recursion-unanswered", "Number of packets unanswered by configured recursor");
 271   S.declare("recursing-answers","Number of recursive answers sent out");
 272   S.declare("recursing-questions","Number of questions sent to recursor");
 273   S.declare("corrupt-packets","Number of corrupt packets received");
 274   S.declare("signatures", "Number of DNSSEC signatures made");
 275   S.declare("tcp-queries","Number of TCP queries received");
 276   S.declare("tcp-answers","Number of answers sent out over TCP");
 277   S.declare("tcp-answers-bytes","Total size of answers sent out over TCP");
 278   S.declare("tcp4-answers-bytes","Total size of answers sent out over TCPv4");
 279   S.declare("tcp6-answers-bytes","Total size of answers sent out over TCPv6");
 280
 281   S.declare("tcp4-queries","Number of IPv4 TCP queries received");
 282   S.declare("tcp4-answers","Number of IPv4 answers sent out over TCP");
 283
 284   S.declare("tcp6-queries","Number of IPv6 TCP queries received");
 285   S.declare("tcp6-answers","Number of IPv6 answers sent out over TCP");
 286
 287
 288   S.declare("qsize-q","Number of questions waiting for database attention", getQCount);
 289
 290   S.declare("dnsupdate-queries", "DNS update packets received.");
 291   S.declare("dnsupdate-answers", "DNS update packets successfully answered.");
 292   S.declare("dnsupdate-refused", "DNS update packets that are refused.");
 293   S.declare("dnsupdate-changes", "DNS update changes to records in total.");
 294
 295   S.declare("incoming-notifications", "NOTIFY packets received.");
 296
 297   S.declare("uptime", "Uptime of process in seconds", uptimeOfProcess);
 298   S.declare("real-memory-usage", "Actual unique use of memory in bytes (approx)", getRealMemoryUsage);
 299   S.declare("fd-usage", "Number of open filedescriptors", getOpenFileDescriptors);
 300 #ifdef __linux__
 301   S.declare("udp-recvbuf-errors", "UDP 'recvbuf' errors", udpErrorStats);
 302   S.declare("udp-sndbuf-errors", "UDP 'sndbuf' errors", udpErrorStats);
 303   S.declare("udp-noport-errors", "UDP 'noport' errors", udpErrorStats);
 304   S.declare("udp-in-errors", "UDP 'in' errors", udpErrorStats);
 305 #endif
 306
 307   S.declare("sys-msec", "Number of msec spent in system time", getSysUserTimeMsec);
 308   S.declare("user-msec", "Number of msec spent in user time", getSysUserTimeMsec);
 309   S.declare("meta-cache-size", "Number of entries in the metadata cache", DNSSECKeeper::dbdnssecCacheSizes);
 310   S.declare("key-cache-size", "Number of entries in the key cache", DNSSECKeeper::dbdnssecCacheSizes);
 311   S.declare("signature-cache-size", "Number of entries in the signature cache", signatureCacheSize);
 312
 313   S.declare("servfail-packets","Number of times a server-failed packet was sent out");
 314   S.declare("latency","Average number of microseconds needed to answer a question", getLatency);
 315   S.declare("timedout-packets","Number of packets which weren't answered within timeout set");
 316   S.declare("security-status", "Security status based on regular polling");
 317   S.declareRing("queries","UDP Queries Received");
 318   S.declareRing("nxdomain-queries","Queries for non-existent records within existent domains");
 319   S.declareRing("noerror-queries","Queries for existing records, but for type we don't have");
 320   S.declareRing("servfail-queries","Queries that could not be answered due to backend errors");
 321   S.declareRing("unauth-queries","Queries for domains that we are not authoritative for");
 322   S.declareRing("logmessages","Log Messages");
 323   S.declareComboRing("remotes","Remote server IP addresses");
 324   S.declareComboRing("remotes-unauth","Remote hosts querying domains for which we are not auth");
 325   S.declareComboRing("remotes-corrupt","Remote hosts sending corrupt packets");
 326 }
 327
 328 int isGuarded(char **argv)
 329 {
 330   char *p=strstr(argv[0],"-instance");
 331
 332   return !!p;
 333 }
 334
 335 void sendout(DNSPacket* a)
 336 {
 337   if(!a)
 338     return;
 339
 340   N->send(a);
 341
 342   int diff=a->d_dt.udiff();
 343   avg_latency=(int)(0.999*avg_latency+0.001*diff);
 344   delete a;
 345 }
 346
 347 //! The qthread receives questions over the internet via the Nameserver class, and hands them to the Distributor for further processing
 348 void *qthread(void *number)
 349 try
 350 {
 351   DNSPacket *P;
 352   DNSDistributor *distributor = DNSDistributor::Create(::arg().asNum("distributor-threads", 1)); // the big dispatcher!
 353   int num = (int)(unsigned long)number;
 354   g_distributors[num] = distributor;
 355   DNSPacket question(true);
 356   DNSPacket cached(false);
 357
 358   AtomicCounter &numreceived=*S.getPointer("udp-queries");
 359   AtomicCounter &numreceiveddo=*S.getPointer("udp-do-queries");
 360
 361   AtomicCounter &numreceived4=*S.getPointer("udp4-queries");
 362
 363   AtomicCounter &numreceived6=*S.getPointer("udp6-queries");
 364   AtomicCounter &overloadDrops=*S.getPointer("overload-drops");
 365
 366   int diff;
 367   bool logDNSQueries = ::arg().mustDo("log-dns-queries");
 368   shared_ptr<UDPNameserver> NS;
 369
 370   // If we have SO_REUSEPORT then create a new port for all receiver threads
 371   // other than the first one.
 372   if( number != NULL && N->canReusePort() ) {
 373     NS = g_udpReceivers[num];
 374     if (NS == nullptr) {
 375       NS = N;
 376     }
 377   } else {
 378     NS = N;
 379   }
 380
 381   for(;;) {
 382     if(!(P=NS->receive(&question))) { // receive a packet         inline
 383       continue;                    // packet was broken, try again
 384     }
 385
 386     numreceived++;
 387
 388     if(P->d_remote.getSocklen()==sizeof(sockaddr_in))
 389       numreceived4++;
 390     else
 391       numreceived6++;
 392
 393     if(P->d_dnssecOk)
 394       numreceiveddo++;
 395
 396      if(P->d.qr)
 397        continue;
 398
 399     S.ringAccount("queries", P->qdomain.toLogString()+"/"+P->qtype.getName());
 400     S.ringAccount("remotes",P->d_remote);
 401     if(logDNSQueries) {
 402       string remote;
 403       if(P->hasEDNSSubnet())
 404         remote = P->getRemote().toString() + "<-" + P->getRealRemote().toString();
 405       else
 406         remote = P->getRemote().toString();
 407       L << Logger::Notice<<"Remote "<< remote <<" wants '" << P->qdomain<<"|"<<P->qtype.getName() <<
 408             "', do = " <<P->d_dnssecOk <<", bufsize = "<< P->getMaxReplyLen()<<": ";
 409     }
 410
 411     if((P->d.opcode != Opcode::Notify && P->d.opcode != Opcode::Update) && P->couldBeCached()) {
 412       bool haveSomething=PC.get(P, &cached); // does the PacketCache recognize this question?
 413       if (haveSomething) {
 414         if(logDNSQueries)
 415           L<<"packetcache HIT"<<endl;
 416         cached.setRemote(&P->d_remote);  // inlined
 417         cached.setSocket(P->getSocket());                               // inlined
 418         cached.d_anyLocal = P->d_anyLocal;
 419         cached.setMaxReplyLen(P->getMaxReplyLen());
 420         cached.d.rd=P->d.rd; // copy in recursion desired bit
 421         cached.d.id=P->d.id;
 422         cached.commitD(); // commit d to the packet                        inlined
 423         NS->send(&cached); // answer it then                              inlined
 424         diff=P->d_dt.udiff();
 425         avg_latency=(int)(0.999*avg_latency+0.001*diff); // 'EWMA'
 426         continue;
 427       }
 428     }
 429
 430     if(distributor->isOverloaded()) {
 431       if(logDNSQueries)
 432         L<<"Dropped query, backends are overloaded"<<endl;
 433       overloadDrops++;
 434       continue;
 435     }
 436
 437     if(logDNSQueries)
 438       L<<"packetcache MISS"<<endl;
 439
 440     try {
 441       distributor->question(P, &sendout); // otherwise, give to the distributor
 442     }
 443     catch(DistributorFatal& df) { // when this happens, we have leaked loads of memory. Bailing out time.
 444       _exit(1);
 445     }
 446   }
 447   return 0;
 448 }
 449 catch(PDNSException& pe)
 450 {
 451   L<<Logger::Error<<"Fatal error in question thread: "<<pe.reason<<endl;
 452   _exit(1);
 453 }
 454
 455 static void* dummyThread(void *)
 456 {
 457   void* ignore=0;
 458   pthread_exit(ignore);
 459 }
 460
 461 static void triggerLoadOfLibraries()
 462 {
 463   pthread_t tid;
 464   pthread_create(&tid, 0, dummyThread, 0);
 465   void* res;
 466   pthread_join(tid, &res);
 467 }
 468
 469 void mainthread()
 470 {
 471    Utility::srandom(time(0) ^ getpid());
 472
 473    int newgid=0;
 474    if(!::arg()["setgid"].empty())
 475      newgid=Utility::makeGidNumeric(::arg()["setgid"]);
 476    int newuid=0;
 477    if(!::arg()["setuid"].empty())
 478      newuid=Utility::makeUidNumeric(::arg()["setuid"]);
 479
 480    g_anyToTcp = ::arg().mustDo("any-to-tcp");
 481    g_8bitDNS = ::arg().mustDo("8bit-dns");
 482
 483    DNSPacket::s_udpTruncationThreshold = std::max(512, ::arg().asNum("udp-truncation-threshold"));
 484    DNSPacket::s_doEDNSSubnetProcessing = ::arg().mustDo("edns-subnet-processing");
 485
 486    PC.setTTL(::arg().asNum("cache-ttl"));
 487    PC.setMaxEntries(::arg().asNum("max-packet-cache-entries"));
 488    QC.setMaxEntries(::arg().asNum("max-cache-entries"));
 489
 490    stubParseResolveConf();
 491
 492    if(!::arg()["chroot"].empty()) {
 493 #ifdef HAVE_SYSTEMD
 494      char *ns;
 495      ns = getenv("NOTIFY_SOCKET");
 496      if (ns != nullptr) {
 497        L<<Logger::Error<<"Unable to chroot when running from systemd. Please disable chroot= or set the 'Type' for this service to 'simple'"<<endl;
 498        exit(1);
 499      }
 500 #endif
 501      triggerLoadOfLibraries();
 502      if(::arg().mustDo("master") || ::arg().mustDo("slave"))
 503         gethostbyname("a.root-servers.net"); // this forces all lookup libraries to be loaded
 504      Utility::dropGroupPrivs(newuid, newgid);
 505      if(chroot(::arg()["chroot"].c_str())<0 || chdir("/")<0) {
 506        L<<Logger::Error<<"Unable to chroot to '"+::arg()["chroot"]+"': "<<strerror(errno)<<", exiting"<<endl;
 507        exit(1);
 508      }
 509      else
 510        L<<Logger::Error<<"Chrooted to '"<<::arg()["chroot"]<<"'"<<endl;
 511    } else {
 512      Utility::dropGroupPrivs(newuid, newgid);
 513    }
 514
 515   AuthWebServer webserver;
 516   Utility::dropUserPrivs(newuid);
 517
 518   // We need to start the Recursor Proxy before doing secpoll, see issue #2453
 519   if(::arg().mustDo("resolver")){
 520     DP=new DNSProxy(::arg()["resolver"]);
 521     DP->go();
 522   }
 523
 524   try {
 525     doSecPoll(true);
 526   }
 527   catch(...) {}
 528
 529   // Some sanity checking on default key settings
 530   for (const string& algotype : {"ksk", "zsk"}) {
 531     int algo, size;
 532     if (::arg()["default-"+algotype+"-algorithm"].empty())
 533       continue;
 534     algo = DNSSECKeeper::shorthand2algorithm(::arg()["default-"+algotype+"-algorithm"]);
 535     size = ::arg().asNum("default-"+algotype+"-size");
 536     if (algo == -1)
 537       L<<Logger::Warning<<"Warning: default-"<<algotype<<"-algorithm set to unknown algorithm: "<<::arg()["default-"+algotype+"-algorithm"]<<endl;
 538     else if (algo <= 10 && size == 0)
 539       L<<Logger::Warning<<"Warning: default-"<<algotype<<"-algorithm is set to an algorithm ("<<::arg()["default-"+algotype+"-algorithm"]<<") that requires a non-zero default-"<<algotype<<"-size!"<<endl;
 540   }
 541
 542   // NOW SAFE TO CREATE THREADS!
 543   dl->go();
 544
 545   pthread_t qtid;
 546
 547   if(::arg().mustDo("webserver") || ::arg().mustDo("api"))
 548     webserver.go();
 549
 550   if(::arg().mustDo("slave") || ::arg().mustDo("master") || !::arg()["forward-notify"].empty())
 551     Communicator.go();
 552
 553   if(TN)
 554     TN->go(); // tcp nameserver launch
 555
 556   //  fork(); (this worked :-))
 557   unsigned int max_rthreads= ::arg().asNum("receiver-threads", 1);
 558   g_distributors.resize(max_rthreads);
 559   for(unsigned int n=0; n < max_rthreads; ++n)
 560     pthread_create(&qtid,0,qthread, reinterpret_cast<void *>(n)); // receives packets
 561
 562   pthread_create(&qtid,0,carbonDumpThread, 0); // runs even w/o carbon, might change @ runtime
 563
 564 #ifdef HAVE_SYSTEMD
 565   /* If we are here, notify systemd that we are ay-ok! This might have some
 566    * timing issues with the backend-threads. e.g. if the initial MySQL connection
 567    * is slow and times out (leading to process termination through the backend)
 568    * We probably have told systemd already that we have started correctly.
 569    */
 570     sd_notify(0, "READY=1");
 571 #endif
 572
 573   for(;;) {
 574     sleep(1800);
 575     try {
 576       doSecPoll(false);
 577     }
 578     catch(...){}
 579   }
 580
 581   L<<Logger::Error<<"Mainthread exiting - should never happen"<<endl;
 582 }