pdns/nameserver.hh

   1 /*
   2     PowerDNS Versatile Database Driven Nameserver
   3     Copyright (C) 2005 - 2011  PowerDNS.COM BV
   4
   5     This program is free software; you can redistribute it and/or modify it
   6     under the terms of the GNU General Public License version 2 as published
   7     by the Free Software Foundation
   8
   9     Additionally, the license of this program contains a special
  10     exception which allows to distribute the program in binary form when
  11     it is linked against OpenSSL.
  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 St, Fifth Floor, Boston, MA  02110-1301  USA
  21 */
  22 #ifndef NAMESERVER_HH
  23 #define NAMESERVER_HH
  24
  25 #include <poll.h>
  26 #include <sys/types.h>
  27 #include <sys/socket.h>
  28 #include <netinet/in.h>
  29 #include <sys/time.h>
  30 #include <unistd.h>
  31 #include <arpa/inet.h>
  32 #include <netdb.h>
  33 #include <vector>
  34
  35 #include "statbag.hh"
  36 #include "namespaces.hh"
  37 #include "dnspacket.hh"
  38 #include "responsestats.hh"
  39
  40 /** This is the main class. It opens a socket on udp port 53 and waits for packets. Those packets can
  41     be retrieved with the receive() member function, which returns a DNSPacket.
  42
  43     Some sample code in main():
  44     \code
  45     typedef Distributor<DNSPacket,DNSPacket,PacketHandler> DNSDistributor;
  46     DNSDistributor D(6); // the big dispatcher!
  47
  48     pthread_t qtid, atid;
  49     N=new UDPNameserver;
  50
  51     pthread_create(&qtid,0,qthread,static_cast<void *>(&D)); // receives packets
  52     pthread_create(&atid,0,athread,static_cast<void *>(&D)); // sends packets
  53     \endcode
  54
  55     Code for qthread:
  56     \code
  57     void *qthread(void *p)
  58     {
  59       DNSDistributor *D=static_cast<DNSDistributor *>(p);
  60
  61       DNSPacket *P;
  62
  63       while((P=N->receive())) // receive a packet
  64       {
  65          D->question(P); // and give to the distributor, they will delete it
  66       }
  67       return 0;
  68     }
  69
  70     \endcode
  71
  72 */
  73
  74 #ifdef __linux__
  75 #ifndef SO_REUSEPORT
  76 #define SO_REUSEPORT 15
  77 #endif
  78 #endif
  79
  80 class UDPNameserver
  81 {
  82 public:
  83   UDPNameserver( bool additional_socket = false );  //!< Opens the socket
  84   DNSPacket *receive(DNSPacket *prefilled=0); //!< call this in a while or for(;;) loop to get packets
  85   void send(DNSPacket *); //!< send a DNSPacket. Will call DNSPacket::truncate() if over 512 bytes
  86   inline bool canReusePort() {
  87 #ifdef SO_REUSEPORT
  88     return d_can_reuseport;
  89 #else
  90     return false;
  91 #endif
  92   };
  93
  94 private:
  95   bool d_additional_socket;
  96 #ifdef SO_REUSEPORT
  97   bool d_can_reuseport;
  98 #endif
  99   vector<int> d_sockets;
 100   void bindIPv4();
 101   void bindIPv6();
 102   vector<pollfd> d_rfds;
 103 };
 104
 105 bool AddressIsUs(const ComboAddress& remote);
 106
 107 extern ResponseStats g_rs;
 108
 109 #endif