pdns/communicator.hh

   1 /*
   2     PowerDNS Versatile Database Driven Nameserver
   3     Copyright (C) 2002  PowerDNS.COM BV
   4
   5     This program is free software; you can redistribute it and/or modify
   6     it under the terms of the GNU General Public License as published by
   7     the Free Software Foundation; either version 2 of the License, or
   8     (at your option) any later version.
   9
  10     This program is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13     GNU General Public License for more details.
  14
  15     You should have received a copy of the GNU General Public License
  16     along with this program; if not, write to the Free Software
  17     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18 */
  19 #ifndef PDNS_COMMUNICATOR_HH
  20 #define PDNS_COMMUNICATOR_HH
  21
  22 #include <pthread.h>
  23 #include <string>
  24 #include <semaphore.h>
  25 #include <queue>
  26 #include <list>
  27
  28 #ifndef WIN32
  29 # include <unistd.h>
  30 # include <fcntl.h>
  31 # include <netdb.h>
  32 #endif // WIN32
  33
  34 #include "lock.hh"
  35 #include "packethandler.hh"
  36
  37 using namespace std;
  38
  39 struct SuckRequest
  40 {
  41   string domain;
  42   string master;
  43 };
  44
  45 class NotificationQueue
  46 {
  47 public:
  48   void add(const string &domain, const string &ip)
  49   {
  50     NotificationRequest nr;
  51     nr.domain   = domain;
  52     nr.ip       = ip;
  53     nr.attempts = 0;
  54     nr.id       = Utility::random()%0xffff;
  55     nr.next     = time(0);
  56
  57     d_nqueue.push_back(nr);
  58   }
  59
  60   bool removeIf(const string &remote, u_int16_t id, const string &domain)
  61   {
  62     for(d_nqueue_t::iterator i=d_nqueue.begin();i!=d_nqueue.end();++i) {
  63       cout<<i->id<<" "<<id<<endl;
  64       cout<<i->ip<<" "<<remote<<endl;
  65       cout<<i->domain<<" "<<domain<<endl;
  66
  67       if(i->id==id && i->ip==remote && i->domain==domain) {
  68         d_nqueue.erase(i);
  69         return true;
  70       }
  71     }
  72     return false;
  73   }
  74
  75   bool getOne(string &domain, string &ip, u_int16_t *id, bool &purged)
  76   {
  77     for(d_nqueue_t::iterator i=d_nqueue.begin();i!=d_nqueue.end();++i)
  78       if(i->next <= time(0)) {
  79         i->attempts++;
  80         purged=false;
  81         i->next=time(0)+1+(1<<i->attempts);
  82         domain=i->domain;
  83         ip=i->ip;
  84         *id=i->id;
  85         purged=false;
  86         if(i->attempts>4) {
  87           purged=true;
  88           d_nqueue.erase(i);
  89         }
  90         return true;
  91       }
  92     return false;
  93   }
  94
  95   time_t earliest()
  96   {
  97     time_t early=1<<31-1; // y2038 problem lurking here :-)
  98     for(d_nqueue_t::const_iterator i=d_nqueue.begin();i!=d_nqueue.end();++i)
  99       early=min(early,i->next);
 100     return early-time(0);
 101   }
 102
 103 private:
 104   struct NotificationRequest
 105   {
 106     string domain;
 107     string ip;
 108     int attempts;
 109     u_int16_t id;
 110     time_t next;
 111   };
 112
 113   typedef list<NotificationRequest>d_nqueue_t;
 114   d_nqueue_t d_nqueue;
 115
 116 };
 117
 118 /** this class contains a thread that communicates with other nameserver and does housekeeping.
 119     Initially, it is notified only of zones that need to be pulled in because they have been updated. */
 120
 121 class CommunicatorClass
 122 {
 123 public:
 124   CommunicatorClass()
 125   {
 126     pthread_mutex_init(&d_lock,0);
 127     pthread_mutex_init(&d_holelock,0);
 128 //    sem_init(&d_suck_sem,0,0);
 129 //    sem_init(&d_any_sem,0,0);
 130     d_tickinterval=60;
 131   }
 132   int doNotifications();
 133   void go()
 134   {
 135     pthread_t tid;
 136     pthread_create(&tid,0,&launchhelper,this);
 137   }
 138
 139   void drillHole(const string &domain, const string &ip);
 140   bool justNotified(const string &domain, const string &ip);
 141   void addSuckRequest(const string &domain, const string &master);
 142   void notify(const string &domain, const string &ip);
 143   void mainloop();
 144   static void *launchhelper(void *p)
 145   {
 146     static_cast<CommunicatorClass *>(p)->mainloop();
 147     return 0;
 148   }
 149   bool notifyDomain(const string &domain);
 150 private:
 151   void makeNotifySocket();
 152   void queueNotifyDomain(const string &domain, DNSBackend *B);
 153   int d_nsock;
 154   map<pair<string,string>,time_t>d_holes;
 155   pthread_mutex_t d_holelock;
 156   void suck(const string &domain, const string &remote);
 157   void slaveRefresh(PacketHandler *P);
 158   void masterUpdateCheck(PacketHandler *P);
 159   pthread_mutex_t d_lock;
 160   queue<SuckRequest> d_suckdomains;
 161   Semaphore d_suck_sem;
 162   Semaphore d_any_sem;
 163   int d_tickinterval;
 164   NotificationQueue d_nq;
 165 };
 166
 167 #endif