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 #include "threadname.hh"
  33
  34 #ifdef HAVE_SYSTEMD
  35 #include <systemd/sd-daemon.h>
  36 #endif
  37
  38 bool g_anyToTcp;
  39 bool g_8bitDNS;
  40 #ifdef HAVE_LUA_RECORDS
  41 bool g_doLuaRecord;
  42 int g_luaRecordExecLimit;
  43 #endif
  44 typedef Distributor<DNSPacket,DNSPacket,PacketHandler> DNSDistributor;
  45
  46 ArgvMap theArg;
  47 StatBag S;  //!< Statistics are gathered across PDNS via the StatBag class S
  48 AuthPacketCache PC; //!< This is the main PacketCache, shared across all threads
  49 AuthQueryCache QC;
  50 DNSProxy *DP;
  51 DynListener *dl;
  52 CommunicatorClass Communicator;
  53 shared_ptr<UDPNameserver> N;
  54 int avg_latency;
  55 TCPNameserver *TN;
  56 static vector<DNSDistributor*> g_distributors;
  57 vector<std::shared_ptr<UDPNameserver> > g_udpReceivers;
  58
  59 ArgvMap &arg()
  60 {
  61   return theArg;
  62 }
  63
  64 void declareArguments()
  65 {
  66   ::arg().set("config-dir","Location of configuration directory (pdns.conf)")=SYSCONFDIR;
  67   ::arg().set("config-name","Name of this virtual configuration - will rename the binary image")="";
  68   ::arg().set("socket-dir",string("Where the controlsocket will live, ")+LOCALSTATEDIR+" when unset and not chrooted" )="";
  69   ::arg().set("module-dir","Default directory for modules")=PKGLIBDIR;
  70   ::arg().set("chroot","If set, chroot to this directory for more security")="";
  71   ::arg().set("logging-facility","Log under a specific facility")="";
  72   ::arg().set("daemon","Operate as a daemon")="no";
  73
  74   ::arg().set("local-port","The port on which we listen")="53";
  75   ::arg().setSwitch("dnsupdate","Enable/Disable DNS update (RFC2136) support. Default is no.")="no";
  76   ::arg().setSwitch("write-pid","Write a PID file")="yes";
  77   ::arg().set("allow-dnsupdate-from","A global setting to allow DNS updates from these IP ranges.")="127.0.0.0/8,::1";
  78   ::arg().setSwitch("send-signed-notify","Send TSIG secured NOTIFY if TSIG key is configured for a domain")="yes";
  79   ::arg().set("allow-unsigned-notify","Allow unsigned notifications for TSIG secured domains")="yes"; //FIXME: change to 'no' later
  80   ::arg().set("allow-unsigned-supermaster", "Allow supermasters to create zones without TSIG signed NOTIFY")="yes";
  81   ::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";
  82   ::arg().setSwitch("log-dns-details","If PDNS should log DNS non-erroneous details")="no";
  83   ::arg().setSwitch("log-dns-queries","If PDNS should log all incoming DNS queries")="no";
  84   ::arg().set("local-address","Local IP addresses to which we bind")="0.0.0.0";
  85   ::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";
  86   ::arg().setSwitch("non-local-bind", "Enable binding to non-local addresses by using FREEBIND / BINDANY socket options")="no";
  87   ::arg().set("local-ipv6","Local IP address to which we bind")="::";
  88   ::arg().setSwitch("reuseport","Enable higher performance on compliant kernels by using SO_REUSEPORT allowing each receiver thread to open its own socket")="no";
  89   ::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";
  90   ::arg().set("query-local-address","Source IP address for sending queries")="0.0.0.0";
  91   ::arg().set("query-local-address6","Source IPv6 address for sending queries")="::";
  92   ::arg().set("overload-queue-length","Maximum queuelength moving to packetcache only")="0";
  93   ::arg().set("max-queue-length","Maximum queuelength before considering situation lost")="5000";
  94
  95   ::arg().set("retrieval-threads", "Number of AXFR-retrieval threads for slave operation")="2";
  96   ::arg().setSwitch("api", "Enable/disable the REST API (including HTTP listener)")="no";
  97   ::arg().set("api-key", "Static pre-shared authentication key for access to the REST API")="";
  98   ::arg().setSwitch("default-api-rectify","Default API-RECTIFY value for zones")="yes";
  99   ::arg().setSwitch("dname-processing", "If we should support DNAME records")="no";
 100
 101   ::arg().setCmd("help","Provide a helpful message");
 102   ::arg().setCmd("version","Output version and compilation date");
 103   ::arg().setCmd("config","Provide configuration file on standard output");
 104   ::arg().setCmd("list-modules","Lists all modules available");
 105   ::arg().setCmd("no-config","Don't parse configuration file");
 106
 107   ::arg().set("version-string","PowerDNS version in packets - full, anonymous, powerdns or custom")="full";
 108   ::arg().set("control-console","Debugging switch - don't use")="no"; // but I know you will!
 109   ::arg().set("loglevel","Amount of logging. Higher is more. Do not set below 3")="4";
 110   ::arg().set("disable-syslog","Disable logging to syslog, useful when running inside a supervisor that logs stdout")="no";
 111   ::arg().set("log-timestamp","Print timestamps in log lines")="yes";
 112   ::arg().set("default-soa-name","name to insert in the SOA record if none set in the backend")="a.misconfigured.powerdns.server";
 113   ::arg().set("default-soa-mail","mail address to insert in the SOA record if none set in the backend")="";
 114   ::arg().set("distributor-threads","Default number of Distributor (backend) threads to start")="3";
 115   ::arg().set("signing-threads","Default number of signer threads to start")="3";
 116   ::arg().set("receiver-threads","Default number of receiver threads to start")="1";
 117   ::arg().set("queue-limit","Maximum number of milliseconds to queue a query")="1500";
 118   ::arg().set("resolver","Use this resolver for ALIAS and the internal stub resolver")="no";
 119   ::arg().set("udp-truncation-threshold", "Maximum UDP response size before we truncate")="1232";
 120   ::arg().set("disable-tcp","Do not listen to TCP queries")="no";
 121
 122   ::arg().set("config-name","Name of this virtual configuration - will rename the binary image")="";
 123
 124   ::arg().set("load-modules","Load this module - supply absolute or relative path")="";
 125   ::arg().set("launch","Which backends to launch and order to query them in")="";
 126   ::arg().setSwitch("disable-axfr","Disable zonetransfers but do allow TCP queries")="no";
 127   ::arg().set("allow-axfr-ips","Allow zonetransfers only to these subnets")="127.0.0.0/8,::1";
 128   ::arg().set("only-notify", "Only send AXFR NOTIFY to these IP addresses or netmasks")="0.0.0.0/0,::/0";
 129   ::arg().set("also-notify", "When notifying a domain, also notify these nameservers")="";
 130   ::arg().set("allow-notify-from","Allow AXFR NOTIFY from these IP ranges. If empty, drop all incoming notifies.")="0.0.0.0/0,::/0";
 131   ::arg().set("slave-cycle-interval","Schedule slave freshness checks once every .. seconds")="60";
 132
 133   ::arg().set("tcp-control-address","If set, PowerDNS can be controlled over TCP on this address")="";
 134   ::arg().set("tcp-control-port","If set, PowerDNS can be controlled over TCP on this address")="53000";
 135   ::arg().set("tcp-control-secret","If set, PowerDNS can be controlled over TCP after passing this secret")="";
 136   ::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";
 137
 138   ::arg().setSwitch("slave","Act as a slave")="no";
 139   ::arg().setSwitch("master","Act as a master")="no";
 140   ::arg().setSwitch("supermaster", "Act as a supermaster")="no";
 141   ::arg().setSwitch("disable-axfr-rectify","Disable the rectify step during an outgoing AXFR. Only required for regression testing.")="no";
 142   ::arg().setSwitch("guardian","Run within a guardian process")="no";
 143   ::arg().setSwitch("prevent-self-notification","Don't send notifications to what we think is ourself")="yes";
 144   ::arg().setSwitch("any-to-tcp","Answer ANY queries with tc=1, shunting to TCP")="yes";
 145   ::arg().setSwitch("edns-subnet-processing","If we should act on EDNS Subnet options")="no";
 146
 147   ::arg().setSwitch("webserver","Start a webserver for monitoring (api=yes also enables the HTTP listener)")="no";
 148   ::arg().setSwitch("webserver-print-arguments","If the webserver should print arguments")="no";
 149   ::arg().set("webserver-address","IP Address of webserver/API to listen on")="127.0.0.1";
 150   ::arg().set("webserver-port","Port of webserver/API to listen on")="8081";
 151   ::arg().set("webserver-password","Password required for accessing the webserver")="";
 152   ::arg().set("webserver-allow-from","Webserver/API access is only allowed from these subnets")="127.0.0.1,::1";
 153
 154   ::arg().setSwitch("do-ipv6-additional-processing", "Do AAAA additional processing")="yes";
 155   ::arg().setSwitch("query-logging","Hint backends that queries should be logged")="no";
 156
 157   ::arg().set("carbon-namespace", "If set overwrites the first part of the carbon string")="pdns";
 158   ::arg().set("carbon-ourname", "If set, overrides our reported hostname for carbon stats")="";
 159   ::arg().set("carbon-instance", "If set overwrites the the instance name default")="auth";
 160   ::arg().set("carbon-server", "If set, send metrics in carbon (graphite) format to this server IP address")="";
 161   ::arg().set("carbon-interval", "Number of seconds between carbon (graphite) updates")="30";
 162
 163   ::arg().set("cache-ttl","Seconds to store packets in the PacketCache")="20";
 164   ::arg().set("negquery-cache-ttl","Seconds to store negative query results in the QueryCache")="60";
 165   ::arg().set("query-cache-ttl","Seconds to store query results in the QueryCache")="20";
 166   ::arg().set("soa-minimum-ttl","Default SOA minimum ttl")="3600";
 167   ::arg().set("server-id", "Returned when queried for 'id.server' TXT or NSID, defaults to hostname - disabled or custom")="";
 168   ::arg().set("soa-refresh-default","Default SOA refresh")="10800";
 169   ::arg().set("soa-retry-default","Default SOA retry")="3600";
 170   ::arg().set("soa-expire-default","Default SOA expire")="604800";
 171   ::arg().set("default-soa-edit","Default SOA-EDIT value")="";
 172   ::arg().set("default-soa-edit-signed","Default SOA-EDIT value for signed zones")="";
 173   ::arg().set("dnssec-key-cache-ttl","Seconds to cache DNSSEC keys from the database")="30";
 174   ::arg().set("domain-metadata-cache-ttl","Seconds to cache domain metadata from the database")="60";
 175
 176   ::arg().set("trusted-notification-proxy", "IP address of incoming notification proxy")="";
 177   ::arg().set("slave-renotify", "If we should send out notifications for slaved updates")="no";
 178   ::arg().set("forward-notify", "IP addresses to forward received notifications to regardless of master or slave settings")="";
 179
 180   ::arg().set("default-ttl","Seconds a result is valid if not set otherwise")="3600";
 181   ::arg().set("max-tcp-connections","Maximum number of TCP connections")="20";
 182   ::arg().set("max-tcp-connections-per-client","Maximum number of simultaneous TCP connections per client")="0";
 183   ::arg().set("max-tcp-transactions-per-conn","Maximum number of subsequent queries per TCP connection")="0";
 184   ::arg().set("max-tcp-connection-duration","Maximum time in seconds that a TCP DNS connection is allowed to stay open.")="0";
 185   ::arg().set("tcp-idle-timeout","Maximum time in seconds that a TCP DNS connection is allowed to stay open while being idle")="5";
 186
 187   ::arg().setSwitch("no-shuffle","Set this to prevent random shuffling of answers - for regression testing")="off";
 188
 189   ::arg().set("setuid","If set, change user id to this uid for more security")="";
 190   ::arg().set("setgid","If set, change group id to this gid for more security")="";
 191
 192   ::arg().set("max-cache-entries", "Maximum number of entries in the query cache")="1000000";
 193   ::arg().set("max-packet-cache-entries", "Maximum number of entries in the packet cache")="1000000";
 194   ::arg().set("max-signature-cache-entries", "Maximum number of signatures cache entries")="";
 195   ::arg().set("max-ent-entries", "Maximum number of empty non-terminals in a zone")="100000";
 196   ::arg().set("entropy-source", "If set, read entropy from this file")="/dev/urandom";
 197
 198   ::arg().set("lua-prequery-script", "Lua script with prequery handler (DO NOT USE)")="";
 199   ::arg().set("lua-dnsupdate-policy-script", "Lua script with DNS update policy handler")="";
 200
 201   ::arg().setSwitch("traceback-handler","Enable the traceback handler (Linux only)")="yes";
 202   ::arg().setSwitch("direct-dnskey","Fetch DNSKEY, CDS and CDNSKEY RRs from backend during DNSKEY or CDS/CDNSKEY synthesis")="no";
 203   ::arg().set("default-ksk-algorithm","Default KSK algorithm")="ecdsa256";
 204   ::arg().set("default-ksk-size","Default KSK size (0 means default)")="0";
 205   ::arg().set("default-zsk-algorithm","Default ZSK algorithm")="";
 206   ::arg().set("default-zsk-size","Default ZSK size (0 means default)")="0";
 207   ::arg().set("max-nsec3-iterations","Limit the number of NSEC3 hash iterations")="500"; // RFC5155 10.3
 208
 209   ::arg().set("include-dir","Include *.conf files from this directory");
 210   ::arg().set("security-poll-suffix","Domain name from which to query security update notifications")="secpoll.powerdns.com.";
 211
 212   ::arg().setSwitch("expand-alias", "Expand ALIAS records")="no";
 213   ::arg().setSwitch("outgoing-axfr-expand-alias", "Expand ALIAS records during outgoing AXFR")="no";
 214   ::arg().setSwitch("8bit-dns", "Allow 8bit dns queries")="no";
 215 #ifdef HAVE_LUA_RECORDS
 216   ::arg().setSwitch("enable-lua-records", "Process LUA records for all zones (metadata overrides this)")="no";
 217   ::arg().set("lua-records-exec-limit", "LUA records scripts execution limit (instructions count). Values <= 0 mean no limit")="1000";
 218 #endif
 219   ::arg().setSwitch("axfr-lower-serial", "Also AXFR a zone from a master with a lower serial")="no";
 220
 221   ::arg().set("lua-axfr-script", "Script to be used to edit incoming AXFRs")="";
 222   ::arg().set("xfr-max-received-mbytes", "Maximum number of megabytes received from an incoming XFR")="100";
 223
 224   ::arg().set("tcp-fast-open", "Enable TCP Fast Open support on the listening sockets, using the supplied numerical value as the queue size")="0";
 225
 226   ::arg().set("rng", "Specify the random number generator to use. Valid values are auto,sodium,openssl,getrandom,arc4random,urandom.")="auto";
 227 }
 228
 229 static time_t s_start=time(0);
 230 static uint64_t uptimeOfProcess(const std::string& str)
 231 {
 232   return time(0) - s_start;
 233 }
 234
 235 static uint64_t getSysUserTimeMsec(const std::string& str)
 236 {
 237   struct rusage ru;
 238   getrusage(RUSAGE_SELF, &ru);
 239
 240   if(str=="sys-msec") {
 241     return (ru.ru_stime.tv_sec*1000ULL + ru.ru_stime.tv_usec/1000);
 242   }
 243   else
 244     return (ru.ru_utime.tv_sec*1000ULL + ru.ru_utime.tv_usec/1000);
 245
 246 }
 247
 248 static uint64_t getQCount(const std::string& str)
 249 try
 250 {
 251   int totcount=0;
 252   for(DNSDistributor* d :  g_distributors) {
 253     if(!d)
 254       continue;
 255     totcount += d->getQueueSize();  // this does locking and other things, so don't get smart
 256   }
 257   return totcount;
 258 }
 259 catch(std::exception& e)
 260 {
 261   g_log<<Logger::Error<<"Had error retrieving queue sizes: "<<e.what()<<endl;
 262   return 0;
 263 }
 264 catch(PDNSException& e)
 265 {
 266   g_log<<Logger::Error<<"Had error retrieving queue sizes: "<<e.reason<<endl;
 267   return 0;
 268 }
 269
 270 static uint64_t getLatency(const std::string& str)
 271 {
 272   return avg_latency;
 273 }
 274
 275 void declareStats(void)
 276 {
 277   S.declare("udp-queries","Number of UDP queries received");
 278   S.declare("udp-do-queries","Number of UDP queries received with DO bit");
 279   S.declare("udp-answers","Number of answers sent out over UDP");
 280   S.declare("udp-answers-bytes","Total size of answers sent out over UDP");
 281   S.declare("udp4-answers-bytes","Total size of answers sent out over UDPv4");
 282   S.declare("udp6-answers-bytes","Total size of answers sent out over UDPv6");
 283
 284   S.declare("udp4-answers","Number of IPv4 answers sent out over UDP");
 285   S.declare("udp4-queries","Number of IPv4 UDP queries received");
 286   S.declare("udp6-answers","Number of IPv6 answers sent out over UDP");
 287   S.declare("udp6-queries","Number of IPv6 UDP queries received");
 288   S.declare("overload-drops","Queries dropped because backends overloaded");
 289
 290   S.declare("rd-queries", "Number of recursion desired questions");
 291   S.declare("recursion-unanswered", "Number of packets unanswered by configured recursor");
 292   S.declare("recursing-answers","Number of recursive answers sent out");
 293   S.declare("recursing-questions","Number of questions sent to recursor");
 294   S.declare("corrupt-packets","Number of corrupt packets received");
 295   S.declare("signatures", "Number of DNSSEC signatures made");
 296   S.declare("tcp-queries","Number of TCP queries received");
 297   S.declare("tcp-answers","Number of answers sent out over TCP");
 298   S.declare("tcp-answers-bytes","Total size of answers sent out over TCP");
 299   S.declare("tcp4-answers-bytes","Total size of answers sent out over TCPv4");
 300   S.declare("tcp6-answers-bytes","Total size of answers sent out over TCPv6");
 301
 302   S.declare("tcp4-queries","Number of IPv4 TCP queries received");
 303   S.declare("tcp4-answers","Number of IPv4 answers sent out over TCP");
 304
 305   S.declare("tcp6-queries","Number of IPv6 TCP queries received");
 306   S.declare("tcp6-answers","Number of IPv6 answers sent out over TCP");
 307
 308
 309   S.declare("qsize-q","Number of questions waiting for database attention", getQCount);
 310
 311   S.declare("dnsupdate-queries", "DNS update packets received.");
 312   S.declare("dnsupdate-answers", "DNS update packets successfully answered.");
 313   S.declare("dnsupdate-refused", "DNS update packets that are refused.");
 314   S.declare("dnsupdate-changes", "DNS update changes to records in total.");
 315
 316   S.declare("incoming-notifications", "NOTIFY packets received.");
 317
 318   S.declare("uptime", "Uptime of process in seconds", uptimeOfProcess);
 319   S.declare("real-memory-usage", "Actual unique use of memory in bytes (approx)", getRealMemoryUsage);
 320   S.declare("fd-usage", "Number of open filedescriptors", getOpenFileDescriptors);
 321 #ifdef __linux__
 322   S.declare("udp-recvbuf-errors", "UDP 'recvbuf' errors", udpErrorStats);
 323   S.declare("udp-sndbuf-errors", "UDP 'sndbuf' errors", udpErrorStats);
 324   S.declare("udp-noport-errors", "UDP 'noport' errors", udpErrorStats);
 325   S.declare("udp-in-errors", "UDP 'in' errors", udpErrorStats);
 326 #endif
 327
 328   S.declare("sys-msec", "Number of msec spent in system time", getSysUserTimeMsec);
 329   S.declare("user-msec", "Number of msec spent in user time", getSysUserTimeMsec);
 330   S.declare("meta-cache-size", "Number of entries in the metadata cache", DNSSECKeeper::dbdnssecCacheSizes);
 331   S.declare("key-cache-size", "Number of entries in the key cache", DNSSECKeeper::dbdnssecCacheSizes);
 332   S.declare("signature-cache-size", "Number of entries in the signature cache", signatureCacheSize);
 333
 334   S.declare("servfail-packets","Number of times a server-failed packet was sent out");
 335   S.declare("latency","Average number of microseconds needed to answer a question", getLatency);
 336   S.declare("timedout-packets","Number of packets which weren't answered within timeout set");
 337   S.declare("security-status", "Security status based on regular polling");
 338   S.declareRing("queries","UDP Queries Received");
 339   S.declareRing("nxdomain-queries","Queries for non-existent records within existent domains");
 340   S.declareRing("noerror-queries","Queries for existing records, but for type we don't have");
 341   S.declareRing("servfail-queries","Queries that could not be answered due to backend errors");
 342   S.declareRing("unauth-queries","Queries for domains that we are not authoritative for");
 343   S.declareRing("logmessages","Log Messages");
 344   S.declareComboRing("remotes","Remote server IP addresses");
 345   S.declareComboRing("remotes-unauth","Remote hosts querying domains for which we are not auth");
 346   S.declareComboRing("remotes-corrupt","Remote hosts sending corrupt packets");
 347 }
 348
 349 int isGuarded(char **argv)
 350 {
 351   char *p=strstr(argv[0],"-instance");
 352
 353   return !!p;
 354 }
 355
 356 void sendout(DNSPacket* a)
 357 {
 358   if(!a)
 359     return;
 360
 361   N->send(a);
 362
 363   int diff=a->d_dt.udiff();
 364   avg_latency=(int)(0.999*avg_latency+0.001*diff);
 365   delete a;
 366 }
 367
 368 //! The qthread receives questions over the internet via the Nameserver class, and hands them to the Distributor for further processing
 369 void *qthread(void *number)
 370 try
 371 {
 372   setThreadName("pdns/receiver");
 373
 374   DNSPacket *P;
 375   DNSDistributor *distributor = DNSDistributor::Create(::arg().asNum("distributor-threads", 1)); // the big dispatcher!
 376   int num = (int)(unsigned long)number;
 377   g_distributors[num] = distributor;
 378   DNSPacket question(true);
 379   DNSPacket cached(false);
 380
 381   AtomicCounter &numreceived=*S.getPointer("udp-queries");
 382   AtomicCounter &numreceiveddo=*S.getPointer("udp-do-queries");
 383
 384   AtomicCounter &numreceived4=*S.getPointer("udp4-queries");
 385
 386   AtomicCounter &numreceived6=*S.getPointer("udp6-queries");
 387   AtomicCounter &overloadDrops=*S.getPointer("overload-drops");
 388
 389   int diff;
 390   bool logDNSQueries = ::arg().mustDo("log-dns-queries");
 391   shared_ptr<UDPNameserver> NS;
 392   std::string buffer;
 393   buffer.resize(DNSPacket::s_udpTruncationThreshold);
 394
 395   // If we have SO_REUSEPORT then create a new port for all receiver threads
 396   // other than the first one.
 397   if( number != NULL && N->canReusePort() ) {
 398     NS = g_udpReceivers[num];
 399     if (NS == nullptr) {
 400       NS = N;
 401     }
 402   } else {
 403     NS = N;
 404   }
 405
 406   for(;;) {
 407     if(!(P=NS->receive(&question, buffer))) { // receive a packet         inline
 408       continue;                    // packet was broken, try again
 409     }
 410
 411     numreceived++;
 412
 413     if(P->d_remote.getSocklen()==sizeof(sockaddr_in))
 414       numreceived4++;
 415     else
 416       numreceived6++;
 417
 418     if(P->d_dnssecOk)
 419       numreceiveddo++;
 420
 421      if(P->d.qr)
 422        continue;
 423
 424     S.ringAccount("queries", P->qdomain.toLogString()+"/"+P->qtype.getName());
 425     S.ringAccount("remotes",P->d_remote);
 426     if(logDNSQueries) {
 427       string remote;
 428       if(P->hasEDNSSubnet())
 429         remote = P->getRemote().toString() + "<-" + P->getRealRemote().toString();
 430       else
 431         remote = P->getRemote().toString();
 432       g_log << Logger::Notice<<"Remote "<< remote <<" wants '" << P->qdomain<<"|"<<P->qtype.getName() <<
 433         "', do = " <<P->d_dnssecOk <<", bufsize = "<< P->getMaxReplyLen();
 434       if(P->d_ednsRawPacketSizeLimit > 0 && P->getMaxReplyLen() != (unsigned int)P->d_ednsRawPacketSizeLimit)
 435         g_log<<" ("<<P->d_ednsRawPacketSizeLimit<<")";
 436       g_log<<": ";
 437     }
 438
 439     if((P->d.opcode != Opcode::Notify && P->d.opcode != Opcode::Update) && P->couldBeCached()) {
 440       bool haveSomething=PC.get(P, &cached); // does the PacketCache recognize this question?
 441       if (haveSomething) {
 442         if(logDNSQueries)
 443           g_log<<"packetcache HIT"<<endl;
 444         cached.setRemote(&P->d_remote);  // inlined
 445         cached.setSocket(P->getSocket());                               // inlined
 446         cached.d_anyLocal = P->d_anyLocal;
 447         cached.setMaxReplyLen(P->getMaxReplyLen());
 448         cached.d.rd=P->d.rd; // copy in recursion desired bit
 449         cached.d.id=P->d.id;
 450         cached.commitD(); // commit d to the packet                        inlined
 451         NS->send(&cached); // answer it then                              inlined
 452         diff=P->d_dt.udiff();
 453         avg_latency=(int)(0.999*avg_latency+0.001*diff); // 'EWMA'
 454         continue;
 455       }
 456     }
 457
 458     if(distributor->isOverloaded()) {
 459       if(logDNSQueries)
 460         g_log<<"Dropped query, backends are overloaded"<<endl;
 461       overloadDrops++;
 462       continue;
 463     }
 464
 465     if(logDNSQueries)
 466       g_log<<"packetcache MISS"<<endl;
 467
 468     try {
 469       distributor->question(P, &sendout); // otherwise, give to the distributor
 470     }
 471     catch(DistributorFatal& df) { // when this happens, we have leaked loads of memory. Bailing out time.
 472       _exit(1);
 473     }
 474   }
 475   return 0;
 476 }
 477 catch(PDNSException& pe)
 478 {
 479   g_log<<Logger::Error<<"Fatal error in question thread: "<<pe.reason<<endl;
 480   _exit(1);
 481 }
 482
 483 static void* dummyThread(void *)
 484 {
 485   void* ignore=0;
 486   pthread_exit(ignore);
 487 }
 488
 489 static void triggerLoadOfLibraries()
 490 {
 491   pthread_t tid;
 492   pthread_create(&tid, 0, dummyThread, 0);
 493   void* res;
 494   pthread_join(tid, &res);
 495 }
 496
 497 void mainthread()
 498 {
 499    Utility::srandom(time(0) ^ getpid());
 500
 501    int newgid=0;
 502    if(!::arg()["setgid"].empty())
 503      newgid=Utility::makeGidNumeric(::arg()["setgid"]);
 504    int newuid=0;
 505    if(!::arg()["setuid"].empty())
 506      newuid=Utility::makeUidNumeric(::arg()["setuid"]);
 507
 508    g_anyToTcp = ::arg().mustDo("any-to-tcp");
 509    g_8bitDNS = ::arg().mustDo("8bit-dns");
 510 #ifdef HAVE_LUA_RECORDS
 511    g_doLuaRecord = ::arg().mustDo("enable-lua-records");
 512    g_luaRecordExecLimit = ::arg().asNum("lua-records-exec-limit");
 513 #endif
 514
 515    DNSPacket::s_udpTruncationThreshold = std::max(512, ::arg().asNum("udp-truncation-threshold"));
 516    DNSPacket::s_doEDNSSubnetProcessing = ::arg().mustDo("edns-subnet-processing");
 517
 518    PC.setTTL(::arg().asNum("cache-ttl"));
 519    PC.setMaxEntries(::arg().asNum("max-packet-cache-entries"));
 520    QC.setMaxEntries(::arg().asNum("max-cache-entries"));
 521
 522    stubParseResolveConf();
 523
 524    if(!::arg()["chroot"].empty()) {
 525 #ifdef HAVE_SYSTEMD
 526      char *ns;
 527      ns = getenv("NOTIFY_SOCKET");
 528      if (ns != nullptr) {
 529        g_log<<Logger::Error<<"Unable to chroot when running from systemd. Please disable chroot= or set the 'Type' for this service to 'simple'"<<endl;
 530        exit(1);
 531      }
 532 #endif
 533      triggerLoadOfLibraries();
 534      if(::arg().mustDo("master") || ::arg().mustDo("slave"))
 535         gethostbyname("a.root-servers.net"); // this forces all lookup libraries to be loaded
 536      Utility::dropGroupPrivs(newuid, newgid);
 537      if(chroot(::arg()["chroot"].c_str())<0 || chdir("/")<0) {
 538        g_log<<Logger::Error<<"Unable to chroot to '"+::arg()["chroot"]+"': "<<strerror(errno)<<", exiting"<<endl;
 539        exit(1);
 540      }
 541      else
 542        g_log<<Logger::Error<<"Chrooted to '"<<::arg()["chroot"]<<"'"<<endl;
 543    } else {
 544      Utility::dropGroupPrivs(newuid, newgid);
 545    }
 546
 547   AuthWebServer webserver;
 548   Utility::dropUserPrivs(newuid);
 549
 550   if(::arg().mustDo("resolver")){
 551     DP=new DNSProxy(::arg()["resolver"]);
 552     DP->go();
 553   }
 554
 555   try {
 556     doSecPoll(true);
 557   }
 558   catch(...) {}
 559
 560   // Some sanity checking on default key settings
 561   for (const string& algotype : {"ksk", "zsk"}) {
 562     int algo, size;
 563     if (::arg()["default-"+algotype+"-algorithm"].empty())
 564       continue;
 565     algo = DNSSECKeeper::shorthand2algorithm(::arg()["default-"+algotype+"-algorithm"]);
 566     size = ::arg().asNum("default-"+algotype+"-size");
 567     if (algo == -1)
 568       g_log<<Logger::Warning<<"Warning: default-"<<algotype<<"-algorithm set to unknown algorithm: "<<::arg()["default-"+algotype+"-algorithm"]<<endl;
 569     else if (algo <= 10 && size == 0)
 570       g_log<<Logger::Warning<<"Warning: default-"<<algotype<<"-algorithm is set to an algorithm ("<<::arg()["default-"+algotype+"-algorithm"]<<") that requires a non-zero default-"<<algotype<<"-size!"<<endl;
 571   }
 572
 573   // NOW SAFE TO CREATE THREADS!
 574   dl->go();
 575
 576   pthread_t qtid;
 577
 578   if(::arg().mustDo("webserver") || ::arg().mustDo("api"))
 579     webserver.go();
 580
 581   if(::arg().mustDo("slave") || ::arg().mustDo("master") || !::arg()["forward-notify"].empty())
 582     Communicator.go();
 583
 584   if(TN)
 585     TN->go(); // tcp nameserver launch
 586
 587   //  fork(); (this worked :-))
 588   unsigned int max_rthreads= ::arg().asNum("receiver-threads", 1);
 589   g_distributors.resize(max_rthreads);
 590   for(unsigned int n=0; n < max_rthreads; ++n)
 591     pthread_create(&qtid,0,qthread, reinterpret_cast<void *>(n)); // receives packets
 592
 593   pthread_create(&qtid,0,carbonDumpThread, 0); // runs even w/o carbon, might change @ runtime
 594
 595 #ifdef HAVE_SYSTEMD
 596   /* If we are here, notify systemd that we are ay-ok! This might have some
 597    * timing issues with the backend-threads. e.g. if the initial MySQL connection
 598    * is slow and times out (leading to process termination through the backend)
 599    * We probably have told systemd already that we have started correctly.
 600    */
 601     sd_notify(0, "READY=1");
 602 #endif
 603
 604   for(;;) {
 605     sleep(1800);
 606     try {
 607       doSecPoll(false);
 608     }
 609     catch(...){}
 610   }
 611
 612   g_log<<Logger::Error<<"Mainthread exiting - should never happen"<<endl;
 613 }