host.cpp

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/*
 * This file is part of OpenTTD.
 * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
 * OpenTTD 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 OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */
 
#include "../../stdafx.h"
#include "../../debug.h"
#include "address.h"
 
#include "../../safeguards.h"
 
static void NetworkFindBroadcastIPsInternal(NetworkAddressList *broadcast);
 
#ifdef _WIN32
static void NetworkFindBroadcastIPsInternal(NetworkAddressList *broadcast) // Win32 implementation
{
  SOCKET sock = socket(AF_INET, SOCK_DGRAM, 0);
  if (sock == INVALID_SOCKET) return;
 
  std::vector<INTERFACE_INFO> ifos;
  ifos.resize(2);
 
  for (;;) {
    DWORD len = 0;
    if (WSAIoctl(sock, SIO_GET_INTERFACE_LIST, nullptr, 0, ifos.data(), static_cast<DWORD>(ifos.size() * sizeof(INTERFACE_INFO)), &len, nullptr, nullptr) == 0) {
      ifos.resize(len / sizeof(INTERFACE_INFO));
      break;
    }
    if (WSAGetLastError() != WSAEFAULT) {
      closesocket(sock);
      return;
    }
    ifos.resize(ifos.size() * 2);
  }
 
  for (auto &ifo : ifos) {
    if (ifo.iiFlags & IFF_LOOPBACK) continue;
    if (!(ifo.iiFlags & IFF_BROADCAST)) continue;
 
    sockaddr_storage address{};
    /* iiBroadcast is unusable, because it always seems to be set to 255.255.255.255. */
    memcpy(&address, &ifo.iiAddress.Address, sizeof(sockaddr));
    reinterpret_cast<sockaddr_in*>(&address)->sin_addr.s_addr = ifo.iiAddress.AddressIn.sin_addr.s_addr | ~ifo.iiNetmask.AddressIn.sin_addr.s_addr;
    NetworkAddress addr(address, sizeof(sockaddr));
    if (std::none_of(broadcast->begin(), broadcast->end(), [&addr](NetworkAddress const &elem) -> bool { return elem == addr; })) broadcast->push_back(addr);
  }
 
  closesocket(sock);
}
 
#else /* not WIN32 */
static void NetworkFindBroadcastIPsInternal(NetworkAddressList *broadcast)
{
  struct ifaddrs *ifap, *ifa;
 
  if (getifaddrs(&ifap) != 0) return;
 
  for (ifa = ifap; ifa != nullptr; ifa = ifa->ifa_next) {
    if (!(ifa->ifa_flags & IFF_BROADCAST)) continue;
    if (ifa->ifa_broadaddr == nullptr) continue;
    if (ifa->ifa_broadaddr->sa_family != AF_INET) continue;
 
    NetworkAddress addr(ifa->ifa_broadaddr, sizeof(sockaddr));
    if (std::none_of(broadcast->begin(), broadcast->end(), [&addr](NetworkAddress const &elem) -> bool { return elem == addr; })) broadcast->push_back(addr);
  }
  freeifaddrs(ifap);
}
#endif /* all NetworkFindBroadcastIPsInternals */
 
void NetworkFindBroadcastIPs(NetworkAddressList *broadcast)
{
  NetworkFindBroadcastIPsInternal(broadcast);
 
  /* Now display to the debug all the detected ips */
  Debug(net, 3, "Detected broadcast addresses:");
  int i = 0;
  for (NetworkAddress &addr : *broadcast) {
    addr.SetPort(NETWORK_DEFAULT_PORT);
    Debug(net, 3, "  {}) {}", i++, addr.GetHostname());
  }
}