pdns/epollmplexer.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 "mplexer.hh"
  26 #include "sstuff.hh"
  27 #include <iostream>
  28 #include <unistd.h>
  29 #include "misc.hh"
  30 #include "syncres.hh"
  31 #ifdef __linux__
  32 #include <sys/epoll.h>
  33 #endif
  34
  35 #include "namespaces.hh"
  36 #include "namespaces.hh"
  37
  38 class EpollFDMultiplexer : public FDMultiplexer
  39 {
  40 public:
  41   EpollFDMultiplexer();
  42   virtual ~EpollFDMultiplexer()
  43   {
  44     close(d_epollfd);
  45   }
  46
  47   virtual int run(struct timeval* tv);
  48
  49   virtual void addFD(callbackmap_t& cbmap, int fd, callbackfunc_t toDo, const funcparam_t& parameter);
  50   virtual void removeFD(callbackmap_t& cbmap, int fd);
  51   string getName()
  52   {
  53     return "epoll";
  54   }
  55 private:
  56   int d_epollfd;
  57   boost::shared_array<epoll_event> d_eevents;
  58   static int s_maxevents; // not a hard maximum
  59 };
  60
  61
  62 static FDMultiplexer* makeEpoll()
  63 {
  64   return new EpollFDMultiplexer();
  65 }
  66
  67 static struct EpollRegisterOurselves
  68 {
  69   EpollRegisterOurselves() {
  70     FDMultiplexer::getMultiplexerMap().insert(make_pair(0, &makeEpoll)); // priority 0!
  71   }
  72 } doItEpoll;
  73
  74
  75 int EpollFDMultiplexer::s_maxevents=1024;
  76 EpollFDMultiplexer::EpollFDMultiplexer() : d_eevents(new epoll_event[s_maxevents])
  77 {
  78   d_epollfd=epoll_create(s_maxevents); // not hard max
  79   if(d_epollfd < 0)
  80     throw FDMultiplexerException("Setting up epoll: "+stringerror());
  81   int fd=socket(AF_INET, SOCK_DGRAM, 0); // for self-test
  82   if(fd < 0)
  83     return;
  84   try {
  85     addReadFD(fd, 0);
  86     removeReadFD(fd);
  87     close(fd);
  88     return;
  89   }
  90   catch(FDMultiplexerException &fe) {
  91     close(fd);
  92     close(d_epollfd);
  93     throw FDMultiplexerException("epoll multiplexer failed self-test: "+string(fe.what()));
  94   }
  95
  96 }
  97
  98 void EpollFDMultiplexer::addFD(callbackmap_t& cbmap, int fd, callbackfunc_t toDo, const funcparam_t& parameter)
  99 {
 100   accountingAddFD(cbmap, fd, toDo, parameter);
 101
 102   struct epoll_event eevent;
 103
 104   eevent.events = (&cbmap == &d_readCallbacks) ? EPOLLIN : EPOLLOUT;
 105
 106   eevent.data.u64=0; // placate valgrind (I love it so much)
 107   eevent.data.fd=fd;
 108
 109   if(epoll_ctl(d_epollfd, EPOLL_CTL_ADD, fd, &eevent) < 0) {
 110     cbmap.erase(fd);
 111     throw FDMultiplexerException("Adding fd to epoll set: "+stringerror());
 112   }
 113 }
 114
 115 void EpollFDMultiplexer::removeFD(callbackmap_t& cbmap, int fd)
 116 {
 117   if(!cbmap.erase(fd))
 118     throw FDMultiplexerException("Tried to remove unlisted fd "+std::to_string(fd)+ " from multiplexer");
 119
 120   struct epoll_event dummy;
 121   dummy.events = 0;
 122   dummy.data.u64 = 0;
 123
 124   if(epoll_ctl(d_epollfd, EPOLL_CTL_DEL, fd, &dummy) < 0)
 125     throw FDMultiplexerException("Removing fd from epoll set: "+stringerror());
 126 }
 127
 128 int EpollFDMultiplexer::run(struct timeval* now)
 129 {
 130   if(d_inrun) {
 131     throw FDMultiplexerException("FDMultiplexer::run() is not reentrant!\n");
 132   }
 133
 134   int ret=epoll_wait(d_epollfd, d_eevents.get(), s_maxevents, 500);
 135   gettimeofday(now,0); // MANDATORY
 136
 137   if(ret < 0 && errno!=EINTR)
 138     throw FDMultiplexerException("epoll returned error: "+stringerror());
 139
 140   if(ret < 1) // thanks AB!
 141     return 0;
 142
 143   d_inrun=true;
 144   for(int n=0; n < ret; ++n) {
 145     d_iter=d_readCallbacks.find(d_eevents[n].data.fd);
 146
 147     if(d_iter != d_readCallbacks.end()) {
 148       d_iter->second.d_callback(d_iter->first, d_iter->second.d_parameter);
 149       continue; // so we don't refind ourselves as writable!
 150     }
 151     d_iter=d_writeCallbacks.find(d_eevents[n].data.fd);
 152
 153     if(d_iter != d_writeCallbacks.end()) {
 154       d_iter->second.d_callback(d_iter->first, d_iter->second.d_parameter);
 155     }
 156   }
 157   d_inrun=false;
 158   return 0;
 159 }
 160
 161 #if 0
 162 void acceptData(int fd, funcparam_t& parameter)
 163 {
 164   cout<<"Have data on fd "<<fd<<endl;
 165   Socket* sock=funcparam_t_cast<Socket*>(parameter);
 166   string packet;
 167   IPEndpoint rem;
 168   sock->recvFrom(packet, rem);
 169   cout<<"Received "<<packet.size()<<" bytes!\n";
 170 }
 171
 172
 173 int main()
 174 {
 175   Socket s(AF_INET, SOCK_DGRAM);
 176
 177   IPEndpoint loc("0.0.0.0", 2000);
 178   s.bind(loc);
 179
 180   EpollFDMultiplexer sfm;
 181
 182   sfm.addReadFD(s.getHandle(), &acceptData, &s);
 183
 184   for(int n=0; n < 100 ; ++n) {
 185     sfm.run();
 186   }
 187   sfm.removeReadFD(s.getHandle());
 188   sfm.removeReadFD(s.getHandle());
 189 }
 190 #endif
 191
 192