danicoin/src/Platform/Linux/System/TcpListener.cpp

// Copyright (c) 2012-2014, The CryptoNote developers, The Bytecoin developers
//
// This file is part of Bytecoin.
//
// Bytecoin is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Bytecoin 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 Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with Bytecoin.  If not, see <http://www.gnu.org/licenses/>.

#include "TcpListener.h"

#include <sys/epoll.h>
#include <unistd.h>
#include <netdb.h>
#include <fcntl.h>
#include <assert.h>
#include <iostream>
#include <cassert>
#include <errno.h>
#include <stdexcept>
#include "Dispatcher.h"
#include "TcpConnection.h"
#include "InterruptedException.h"

using namespace System;

namespace {

struct ListenerContext : public Dispatcher::ContextExt {
  bool interrupted;
};

}

TcpListener::TcpListener() : dispatcher(nullptr) {
}

TcpListener::TcpListener(TcpListener&& other) : dispatcher(other.dispatcher) {
  if (other.dispatcher != nullptr) {
    listener = other.listener;
    stopped = other.stopped;
    context = other.context;
    other.dispatcher = nullptr;
  }
}

TcpListener::~TcpListener() {
  if (dispatcher != nullptr) {
    assert(context == nullptr);
    if (close(listener) == -1) {
      std::cerr << "close() failed, errno=" << errno << '.' << std::endl;
    }
  }
}

TcpListener& TcpListener::operator=(TcpListener&& other) {
  if (dispatcher != nullptr) {
    assert(context == nullptr);
    if (close(listener) == -1) {
      std::cerr << "close() failed, errno=" << errno << '.' << std::endl;
      throw std::runtime_error("TcpListener::operator=");
    }
  }

  dispatcher = other.dispatcher;
  if (other.dispatcher != nullptr) {
    listener = other.listener;
    stopped = other.stopped;
    context = other.context;
    other.dispatcher = nullptr;
  }

  return *this;
}

void TcpListener::start() {
  assert(dispatcher != nullptr);
  assert(stopped);
  stopped = false;
}

TcpListener::TcpListener(Dispatcher& dispatcher, const std::string& address, uint16_t port) : dispatcher(&dispatcher) {
  listener = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
  if (listener == -1) {
    std::cerr << "socket failed, errno=" << errno << std::endl;
  } else {
    int flags = fcntl(listener, F_GETFL, 0);
    if (flags == -1 || fcntl(listener, F_SETFL, flags | O_NONBLOCK) == -1) {
      std::cerr << "fcntl() failed errno=" << errno << std::endl;
    } else {
      sockaddr_in address;
      address.sin_family = AF_INET;
      address.sin_port = htons(port);
      address.sin_addr.s_addr = INADDR_ANY;
      if (bind(listener, reinterpret_cast<sockaddr*>(&address), sizeof address) != 0) {
        std::cerr << "bind failed, errno=" << errno << std::endl;
      } else if (listen(listener, SOMAXCONN) != 0) {
        std::cerr << "listen failed, errno=" << errno << std::endl;
      } else {
        epoll_event listenEvent;
        listenEvent.data.fd = listener;
        listenEvent.events = 0;
        listenEvent.data.ptr = nullptr;

        if (epoll_ctl(dispatcher.getEpoll(), EPOLL_CTL_ADD, listener, &listenEvent) == -1) {
          std::cerr << "epoll_ctl() failed, errno=" << errno << '.' << std::endl;
        } else {
          stopped = false;
          context = nullptr;
          return;
        }
      }
    }

    if (close(listener) == -1) {
      std::cerr << "close failed, errno=" << errno << std::endl;
    }
  }

  throw std::runtime_error("TcpListener::TcpListener");
}

TcpConnection TcpListener::accept() {
  assert(dispatcher != nullptr);
  assert(context == nullptr);
  if (stopped) {
    throw InterruptedException();
  }

  ListenerContext context2;
  context2.context = dispatcher->getCurrentContext();
  context2.writeContext = nullptr;
  context2.interrupted = false;

  epoll_event listenEvent;
  listenEvent.data.fd = listener;
  listenEvent.events = EPOLLIN | EPOLLONESHOT;
  listenEvent.data.ptr = &context2;

  if (epoll_ctl(dispatcher->getEpoll(), EPOLL_CTL_MOD, listener, &listenEvent) == -1) {
    std::cerr << "epoll_ctl() failed, errno=" << errno << '.' << std::endl;
  } else {
    context = &context2;
    dispatcher->yield();
    assert(dispatcher != nullptr);
    assert(context2.context == dispatcher->getCurrentContext());
    assert(context2.writeContext == nullptr);
    assert(context == &context2);
    context = nullptr;
    context2.context = nullptr;
    if (context2.interrupted) {
      if (close(listener) == -1) {
        std::cerr << "close failed, errno=" << errno << std::endl;
      }
      throw InterruptedException();
    }

    sockaddr inAddr;
    socklen_t inLen = sizeof(inAddr);
    int connection = ::accept(listener, &inAddr, &inLen);
    if (connection == -1) {
      std::cerr << "accept() failed, errno=" << errno << '.' << std::endl;
    } else {
      int flags = fcntl(connection, F_GETFL, 0);
      if (flags == -1 || fcntl(connection, F_SETFL, flags | O_NONBLOCK) == -1) {
        std::cerr << "fcntl() failed errno=" << errno << std::endl;
      } else {
        return TcpConnection(*dispatcher, connection);
      }
    }
  }

  throw std::runtime_error("TcpListener::accept");
}

void TcpListener::stop() {
  assert(dispatcher != nullptr);
  assert(!stopped);
  if (context != nullptr) {
    ListenerContext* context2 = static_cast<ListenerContext*>(context);
    if (!context2->interrupted) {
      context2->interrupted = true;

      epoll_event listenEvent;
      listenEvent.data.fd = listener;
      listenEvent.events = 0;
      listenEvent.data.ptr = nullptr;

      if (epoll_ctl(dispatcher->getEpoll(), EPOLL_CTL_MOD, listener, &listenEvent) == -1) {
        std::cerr << "epoll_ctl() failed, errno=" << errno << '.' << std::endl;
        throw std::runtime_error("TcpListener::stop");
      }

      dispatcher->pushContext(context2->context);
    }
  }

  stopped = true;
}