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 #ifdef __linux__
  31 #include <sys/epoll.h>
  32 #endif
  33
  34 #include "namespaces.hh"
  35
  36 class EpollFDMultiplexer : public FDMultiplexer
  37 {
  38 public:
  39   EpollFDMultiplexer();
  40   virtual ~EpollFDMultiplexer()
  41   {
  42     close(d_epollfd);
  43   }
  44
  45   virtual int run(struct timeval* tv, int timeout=500) override;
  46   virtual void getAvailableFDs(std::vector<int>& fds, int timeout) override;
  47
  48   virtual void addFD(callbackmap_t& cbmap, int fd, callbackfunc_t toDo, const funcparam_t& parameter, const struct timeval* ttd=nullptr) override;
  49   virtual void removeFD(callbackmap_t& cbmap, int fd) override;
  50   string getName() const override
  51   {
  52     return "epoll";
  53   }
  54 private:
  55   int d_epollfd;
  56   boost::shared_array<epoll_event> d_eevents;
  57   static int s_maxevents; // not a hard maximum
  58 };
  59
  60
  61 static FDMultiplexer* makeEpoll()
  62 {
  63   return new EpollFDMultiplexer();
  64 }
  65
  66 static struct EpollRegisterOurselves
  67 {
  68   EpollRegisterOurselves() {
  69     FDMultiplexer::getMultiplexerMap().insert(make_pair(0, &makeEpoll)); // priority 0!
  70   }
  71 } doItEpoll;
  72
  73 int EpollFDMultiplexer::s_maxevents=1024;
  74
  75 EpollFDMultiplexer::EpollFDMultiplexer() : d_eevents(new epoll_event[s_maxevents])
  76 {
  77   d_epollfd=epoll_create(s_maxevents); // not hard max
  78   if(d_epollfd < 0)
  79     throw FDMultiplexerException("Setting up epoll: "+stringerror());
  80   int fd=socket(AF_INET, SOCK_DGRAM, 0); // for self-test
  81   if(fd < 0)
  82     return;
  83   try {
  84     addReadFD(fd, 0);
  85     removeReadFD(fd);
  86     close(fd);
  87     return;
  88   }
  89   catch(FDMultiplexerException &fe) {
  90     close(fd);
  91     close(d_epollfd);
  92     throw FDMultiplexerException("epoll multiplexer failed self-test: "+string(fe.what()));
  93   }
  94
  95 }
  96
  97 void EpollFDMultiplexer::addFD(callbackmap_t& cbmap, int fd, callbackfunc_t toDo, const funcparam_t& parameter, const struct timeval* ttd)
  98 {
  99   accountingAddFD(cbmap, fd, toDo, parameter, ttd);
 100
 101   struct epoll_event eevent;
 102
 103   eevent.events = (&cbmap == &d_readCallbacks) ? EPOLLIN : EPOLLOUT;
 104
 105   eevent.data.u64=0; // placate valgrind (I love it so much)
 106   eevent.data.fd=fd;
 107
 108   if(epoll_ctl(d_epollfd, EPOLL_CTL_ADD, fd, &eevent) < 0) {
 109     cbmap.erase(fd);
 110     throw FDMultiplexerException("Adding fd to epoll set: "+stringerror());
 111   }
 112 }
 113
 114 void EpollFDMultiplexer::removeFD(callbackmap_t& cbmap, int fd)
 115 {
 116   if(!cbmap.erase(fd))
 117     throw FDMultiplexerException("Tried to remove unlisted fd "+std::to_string(fd)+ " from multiplexer");
 118
 119   struct epoll_event dummy;
 120   dummy.events = 0;
 121   dummy.data.u64 = 0;
 122
 123   if(epoll_ctl(d_epollfd, EPOLL_CTL_DEL, fd, &dummy) < 0)
 124     throw FDMultiplexerException("Removing fd from epoll set: "+stringerror());
 125 }
 126
 127 void EpollFDMultiplexer::getAvailableFDs(std::vector<int>& fds, int timeout)
 128 {
 129   int ret=epoll_wait(d_epollfd, d_eevents.get(), s_maxevents, timeout);
 130
 131   if(ret < 0 && errno!=EINTR)
 132     throw FDMultiplexerException("epoll returned error: "+stringerror());
 133
 134   for(int n=0; n < ret; ++n) {
 135     fds.push_back(d_eevents[n].data.fd);
 136   }
 137 }
 138
 139 int EpollFDMultiplexer::run(struct timeval* now, int timeout)
 140 {
 141   if(d_inrun) {
 142     throw FDMultiplexerException("FDMultiplexer::run() is not reentrant!\n");
 143   }
 144
 145   int ret=epoll_wait(d_epollfd, d_eevents.get(), s_maxevents, timeout);
 146   gettimeofday(now,0); // MANDATORY
 147
 148   if(ret < 0 && errno!=EINTR)
 149     throw FDMultiplexerException("epoll returned error: "+stringerror());
 150
 151   if(ret < 1) // thanks AB!
 152     return 0;
 153
 154   d_inrun=true;
 155   for(int n=0; n < ret; ++n) {
 156     d_iter=d_readCallbacks.find(d_eevents[n].data.fd);
 157
 158     if(d_iter != d_readCallbacks.end()) {
 159       d_iter->d_callback(d_iter->d_fd, d_iter->d_parameter);
 160       continue; // so we don't refind ourselves as writable!
 161     }
 162     d_iter=d_writeCallbacks.find(d_eevents[n].data.fd);
 163
 164     if(d_iter != d_writeCallbacks.end()) {
 165       d_iter->d_callback(d_iter->d_fd, d_iter->d_parameter);
 166     }
 167   }
 168   d_inrun=false;
 169   return ret;
 170 }
 171
 172 #if 0
 173 void acceptData(int fd, funcparam_t& parameter)
 174 {
 175   cout<<"Have data on fd "<<fd<<endl;
 176   Socket* sock=funcparam_t_cast<Socket*>(parameter);
 177   string packet;
 178   IPEndpoint rem;
 179   sock->recvFrom(packet, rem);
 180   cout<<"Received "<<packet.size()<<" bytes!\n";
 181 }
 182
 183
 184 int main()
 185 {
 186   Socket s(AF_INET, SOCK_DGRAM);
 187
 188   IPEndpoint loc("0.0.0.0", 2000);
 189   s.bind(loc);
 190
 191   EpollFDMultiplexer sfm;
 192
 193   sfm.addReadFD(s.getHandle(), &acceptData, &s);
 194
 195   for(int n=0; n < 100 ; ++n) {
 196     sfm.run();
 197   }
 198   sfm.removeReadFD(s.getHandle());
 199   sfm.removeReadFD(s.getHandle());
 200 }
 201 #endif
 202
 203