text: /*
   * libjingle
   * Copyright 2008, Google Inc.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are met:
   *
   *  1. Redistributions of source code must retain the above copyright notice,
   *     this list of conditions and the following disclaimer.
   *  2. Redistributions in binary form must reproduce the above copyright notice,
   *     this list of conditions and the following disclaimer in the documentation
   *     and/or other materials provided with the distribution.
   *  3. The name of the author may not be used to endorse or promote products
   *     derived from this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
   * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
   * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
   * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
   * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
   * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
   * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  #include "base/nethelpers.h"
  
  #if defined(WIN32)
  #include <ws2spi.h>
  #include <ws2tcpip.h>
  #include "base/win32.h"
  #endif
  
  #include "base/byteorder.h"
  #include "base/signalthread.h"
  
  namespace talk_base {
  
  int ResolveHostname(const std::string& hostname, int family,
                      std::vector<IPAddress>* addresses) {
    if (!addresses) {
      return -1;
    }
    addresses->clear();
    struct addrinfo* result = NULL;
    struct addrinfo hints = {0};
    // TODO(djw): For now this is IPv4 only so existing users remain unaffected.
    hints.ai_family = AF_INET;
    hints.ai_flags = AI_ADDRCONFIG;
    int ret = getaddrinfo(hostname.c_str(), NULL, &hints, &result);
    if (ret != 0) {
      return ret;
    }
    struct addrinfo* cursor = result;
    for (; cursor; cursor = cursor->ai_next) {
      if (family == AF_UNSPEC || cursor->ai_family == family) {
        IPAddress ip;
        if (IPFromAddrInfo(cursor, &ip)) {
          addresses->push_back(ip);
        }
      }
    }
    freeaddrinfo(result);
    return 0;
  }
  
  // AsyncResolver
  AsyncResolver::AsyncResolver() : error_(0) {
  }
  
  void AsyncResolver::DoWork() {
    error_ = ResolveHostname(addr_.hostname().c_str(), addr_.family(),
                             &addresses_);
  }
  
  void AsyncResolver::OnWorkDone() {
    if (addresses_.size() > 0) {
      addr_.SetIP(addresses_[0]);
    }
  }
  
  const char* inet_ntop(int af, const void *src, char* dst, socklen_t size) {
  #ifdef WIN32
    return win32_inet_ntop(af, src, dst, size);
  #else
    return ::inet_ntop(af, src, dst, size);
  #endif
  }
  
  int inet_pton(int af, const char* src, void *dst) {
  #ifdef WIN32
    return win32_inet_pton(af, src, dst);
  #else
    return ::inet_pton(af, src, dst);
  #endif
  }
  
  bool HasIPv6Enabled() {
  #ifndef WIN32
    // We only need to check this for Windows XP (so far).
    return true;
  #else
    if (IsWindowsVistaOrLater()) {
      return true;
    }
    if (!IsWindowsXpOrLater()) {
      return false;
    }
    DWORD protbuff_size = 4096;
    scoped_array<char> protocols;
    LPWSAPROTOCOL_INFOW protocol_infos = NULL;
    int requested_protocols[2] = {AF_INET6, 0};
  
    int err = 0;
    int ret = 0;
    // Check for protocols in a do-while loop until we provide a buffer large
    // enough. (WSCEnumProtocols sets protbuff_size to its desired value).
    // It is extremely unlikely that this will loop more than once.
    do {
      protocols.reset(new char[protbuff_size]);
      protocol_infos = reinterpret_cast<LPWSAPROTOCOL_INFOW>(protocols.get());
      ret = WSCEnumProtocols(requested_protocols, protocol_infos,
                             &protbuff_size, &err);
    } while (ret == SOCKET_ERROR && err == WSAENOBUFS);
  
    if (ret == SOCKET_ERROR) {
      return false;
    }
  
    // Even if ret is positive, check specifically for IPv6.
    // Non-IPv6 enabled WinXP will still return a RAW protocol.
    for (int i = 0; i < ret; ++i) {
      if (protocol_infos[i].iAddressFamily == AF_INET6) {
        return true;
      }
    }
    return false;
  #endif
  }
  }  // namespace talk_base
  