1 files changed, 237 insertions, 0 deletions
diff --git a/epollmplexer.cc b/epollmplexer.cc
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--- /dev/null
+++ b/epollmplexer.cc
@@ -0,0 +1,237 @@
+/*
+ * This file is part of PowerDNS or dnsdist.
+ * Copyright -- PowerDNS.COM B.V. and its contributors
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * In addition, for the avoidance of any doubt, permission is granted to
+ * link this program with OpenSSL and to (re)distribute the binaries
+ * produced as the result of such linking.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+#include "mplexer.hh"
+#include "sstuff.hh"
+#include <iostream>
+#include <unistd.h>
+#include "misc.hh"
+#ifdef __linux__
+#include <sys/epoll.h>
+#endif
+
+#include "namespaces.hh"
+
+class EpollFDMultiplexer : public FDMultiplexer
+{
+public:
+  EpollFDMultiplexer(unsigned int maxEventsHint);
+  ~EpollFDMultiplexer()
+  {
+    if (d_epollfd >= 0) {
+      close(d_epollfd);
+    }
+  }
+
+  int run(struct timeval* tv, int timeout = 500) override;
+  void getAvailableFDs(std::vector<int>& fds, int timeout) override;
+
+  void addFD(int fd, FDMultiplexer::EventKind kind) override;
+  void removeFD(int fd, FDMultiplexer::EventKind kind) override;
+  void alterFD(int fd, FDMultiplexer::EventKind from, FDMultiplexer::EventKind to) override;
+
+  string getName() const override
+  {
+    return "epoll";
+  }
+
+private:
+  int d_epollfd;
+  std::vector<epoll_event> d_eevents;
+};
+
+static FDMultiplexer* makeEpoll(unsigned int maxEventsHint)
+{
+  return new EpollFDMultiplexer(maxEventsHint);
+}
+
+static struct EpollRegisterOurselves
+{
+  EpollRegisterOurselves()
+  {
+    FDMultiplexer::getMultiplexerMap().emplace(0, &makeEpoll); // priority 0!
+  }
+} doItEpoll;
+
+EpollFDMultiplexer::EpollFDMultiplexer(unsigned int maxEventsHint) :
+  d_eevents(maxEventsHint)
+{
+  d_epollfd = epoll_create(static_cast<int>(maxEventsHint)); // not hard max, just a hint that is actually ignored since Linux 2.6.8
+  if (d_epollfd < 0) {
+    throw FDMultiplexerException("Setting up epoll: " + stringerror());
+  }
+  int fd = socket(AF_INET, SOCK_DGRAM, 0); // for self-test
+
+  if (fd < 0) {
+    return;
+  }
+
+  try {
+    addReadFD(fd, 0);
+    removeReadFD(fd);
+    close(fd);
+    return;
+  }
+  catch (const FDMultiplexerException& fe) {
+    close(fd);
+    close(d_epollfd);
+    throw FDMultiplexerException("epoll multiplexer failed self-test: " + string(fe.what()));
+  }
+}
+
+static uint32_t convertEventKind(FDMultiplexer::EventKind kind)
+{
+  switch (kind) {
+  case FDMultiplexer::EventKind::Read:
+    return EPOLLIN;
+  case FDMultiplexer::EventKind::Write:
+    return EPOLLOUT;
+  case FDMultiplexer::EventKind::Both:
+    return EPOLLIN | EPOLLOUT;
+  }
+
+  throw std::runtime_error("Unhandled event kind in the epoll multiplexer");
+}
+
+void EpollFDMultiplexer::addFD(int fd, FDMultiplexer::EventKind kind)
+{
+  struct epoll_event eevent;
+
+  eevent.events = convertEventKind(kind);
+
+  eevent.data.u64 = 0; // placate valgrind (I love it so much)
+  eevent.data.fd = fd;
+
+  if (epoll_ctl(d_epollfd, EPOLL_CTL_ADD, fd, &eevent) < 0) {
+    throw FDMultiplexerException("Adding fd to epoll set: " + stringerror());
+  }
+}
+
+void EpollFDMultiplexer::removeFD(int fd, FDMultiplexer::EventKind)
+{
+  struct epoll_event dummy;
+  dummy.events = 0;
+  dummy.data.u64 = 0;
+
+  if (epoll_ctl(d_epollfd, EPOLL_CTL_DEL, fd, &dummy) < 0) {
+    throw FDMultiplexerException("Removing fd from epoll set: " + stringerror());
+  }
+}
+
+void EpollFDMultiplexer::alterFD(int fd, FDMultiplexer::EventKind, FDMultiplexer::EventKind to)
+{
+  struct epoll_event eevent;
+  eevent.events = convertEventKind(to);
+  eevent.data.u64 = 0; // placate valgrind (I love it so much)
+  eevent.data.fd = fd;
+
+  if (epoll_ctl(d_epollfd, EPOLL_CTL_MOD, fd, &eevent) < 0) {
+    throw FDMultiplexerException("Altering fd in epoll set: " + stringerror());
+  }
+}
+
+void EpollFDMultiplexer::getAvailableFDs(std::vector<int>& fds, int timeout)
+{
+  int ret = epoll_wait(d_epollfd, d_eevents.data(), d_eevents.size(), timeout);
+
+  if (ret < 0 && errno != EINTR) {
+    throw FDMultiplexerException("epoll returned error: " + stringerror());
+  }
+
+  for (int n = 0; n < ret; ++n) {
+    fds.push_back(d_eevents[n].data.fd);
+  }
+}
+
+int EpollFDMultiplexer::run(struct timeval* now, int timeout)
+{
+  if (d_inrun) {
+    throw FDMultiplexerException("FDMultiplexer::run() is not reentrant!\n");
+  }
+
+  int ret = epoll_wait(d_epollfd, d_eevents.data(), d_eevents.size(), timeout);
+  gettimeofday(now, nullptr); // MANDATORY
+
+  if (ret < 0 && errno != EINTR) {
+    throw FDMultiplexerException("epoll returned error: " + stringerror());
+  }
+
+  if (ret < 1) { // thanks AB!
+    return 0;
+  }
+
+  d_inrun = true;
+  int count = 0;
+  for (int n = 0; n < ret; ++n) {
+    if ((d_eevents[n].events & EPOLLIN) || (d_eevents[n].events & EPOLLERR) || (d_eevents[n].events & EPOLLHUP)) {
+      const auto& iter = d_readCallbacks.find(d_eevents[n].data.fd);
+      if (iter != d_readCallbacks.end()) {
+        iter->d_callback(iter->d_fd, iter->d_parameter);
+        count++;
+      }
+    }
+
+    if ((d_eevents[n].events & EPOLLOUT) || (d_eevents[n].events & EPOLLERR) || (d_eevents[n].events & EPOLLHUP)) {
+      const auto& iter = d_writeCallbacks.find(d_eevents[n].data.fd);
+      if (iter != d_writeCallbacks.end()) {
+        iter->d_callback(iter->d_fd, iter->d_parameter);
+        count++;
+      }
+    }
+  }
+
+  d_inrun = false;
+  return count;
+}
+
+#if 0
+void acceptData(int fd, funcparam_t& parameter)
+{
+  cout<<"Have data on fd "<<fd<<endl;
+  Socket* sock=funcparam_t_cast<Socket*>(parameter);
+  string packet;
+  IPEndpoint rem;
+  sock->recvFrom(packet, rem);
+  cout<<"Received "<<packet.size()<<" bytes!\n";
+}
+
+
+int main()
+{
+  Socket s(AF_INET, SOCK_DGRAM);
+
+  IPEndpoint loc("0.0.0.0", 2000);
+  s.bind(loc);
+
+  EpollFDMultiplexer sfm;
+
+  sfm.addReadFD(s.getHandle(), &acceptData, &s);
+
+  for(int n=0; n < 100 ; ++n) {
+    sfm.run();
+  }
+  sfm.removeReadFD(s.getHandle());
+  sfm.removeReadFD(s.getHandle());
+}
+#endif