C++获取本机网络参数（IP、子网掩码、网关、DNS）

#pragma comment(lib,"Ws2_32.lib")
#include
#pragma comment(lib, "Iphlpapi.lib")
using namespace std;
typedef struct tagNetworkCfg
{
 char szIP[18];
 char szNetmask[18];
 char szGateway[18];
 char szDns1[18];
 char szDns2[18];
}NetworkCfg;
bool GetNetworkCfg(NetworkCfg *cfg)
{
 log_printf("Get network config");
 //获取网卡名称 网卡名称，网卡别名
 string strAdapterName,strAdapterAlias;
 HKEY hKey, hSubKey, hNdiIntKey;
 if(RegOpenKeyEx(HKEY_LOCAL_MACHINE,
  "SystemCurrentControlSetControlClass{4d36e972-e325-11ce-bfc1-08002be10318}",
  0,
  KEY_READ,
  &hKey) != ERROR_SUCCESS)
  return FALSE;

 DWORD dwIndex = 0;
 DWORD dwBufSize = 256;
 DWORD dwDataType;
 char szSubKey[256];
 unsigned char szData[256];

 while(RegEnumKeyEx(hKey, dwIndex++, szSubKey, &dwBufSize, NULL, NULL, NULL, NULL) == ERROR_SUCCESS)
 {
  if(RegOpenKeyEx(hKey, szSubKey, 0, KEY_READ, &hSubKey) == ERROR_SUCCESS)
  {       
   if(RegOpenKeyEx(hSubKey, "NdiInterfaces", 0, KEY_READ, &hNdiIntKey) == ERROR_SUCCESS)
   {
    dwBufSize = 256;
    if(RegQueryValueEx(hNdiIntKey, "LowerRange", 0, &dwDataType, szData, &dwBufSize) == ERROR_SUCCESS)
    {
     if(strstr((char*)szData, "ethernet") != NULL)//    判断是不是以太网卡
     {
      dwBufSize = 256;
      if(RegQueryValueEx(hSubKey, "DriverDesc", 0, &dwDataType, szData, &dwBufSize) == ERROR_SUCCESS)
      {
       strAdapterName = (LPCTSTR)szData;
       dwBufSize = 256;
       if(RegQueryValueEx(hSubKey, "NetCfgInstanceID", 0, &dwDataType, szData, &dwBufSize) == ERROR_SUCCESS)
       {
        strAdapterAlias = (LPCTSTR)szData;
        break;
       }
      }
     }
    }
    RegCloseKey(hNdiIntKey);
   }
   RegCloseKey(hSubKey);
  }

  dwBufSize = 256;
 }    /* end of while */

 RegCloseKey(hKey);
 if (strAdapterName.empty() || strAdapterAlias.empty())
 {
  log_printf("failed to get network config");
  return false;
 }
 string strKeyName = "SYSTEMCurrentControlSetServicesTcpipParametersInterfaces";
 strKeyName += strAdapterAlias;
 if(RegOpenKeyEx(HKEY_LOCAL_MACHINE,
    strKeyName.c_str(),
    0,
    KEY_READ,
    &hKey) != ERROR_SUCCESS)
  return FALSE;
 dwBufSize = 256;
 if(RegQueryValueEx(hKey, "DhcpIPAddress", 0,&dwDataType, szData, &dwBufSize) == ERROR_SUCCESS)
  strcpy(cfg->szIP,(LPCTSTR)szData);
 else{
  if(RegQueryValueEx(hKey, "IPAddress", 0, &dwDataType, szData, &dwBufSize) == ERROR_SUCCESS)
   strcpy(cfg->szIP,(LPCTSTR)szData);
 }
   
 dwBufSize = 256;
 if(RegQueryValueEx(hKey, "DhcpSubnetMask", 0, &dwDataType, szData, &dwBufSize) == ERROR_SUCCESS)
  strcpy(cfg->szNetmask,(LPCTSTR)szData);
 else
 {
  if(RegQueryValueEx(hKey, "SubnetMask", 0, &dwDataType, szData, &dwBufSize) == ERROR_SUCCESS)
   strcpy(cfg->szNetmask,(LPCTSTR)szData);
 }
   
 dwBufSize = 256;
 if(RegQueryValueEx(hKey, "DhcpDefaultGateway", 0, &dwDataType, szData, &dwBufSize) == ERROR_SUCCESS)
  strcpy(cfg->szGateway,(LPCTSTR)szData);
 else
 {
  if(RegQueryValueEx(hKey, "DefaultGateway", 0, &dwDataType, szData, &dwBufSize) == ERROR_SUCCESS)
   strcpy(cfg->szGateway,(LPCSTR)szData);
 }
 RegCloseKey(hKey);

 //获取DNS服务器信息
 FIXED_INFO *fi =  (FIXED_INFO *)GlobalAlloc(GPTR,sizeof( FIXED_INFO));
 ULONG ulOutBufLen = sizeof(FIXED_INFO);
 DWORD ret = ::GetNetworkParams(fi, &ulOutBufLen);
 if(ret != ERROR_SUCCESS)
 {
  GlobalFree(fi);
  fi =  (FIXED_INFO *) GlobalAlloc( GPTR, ulOutBufLen );
  ret = ::GetNetworkParams(fi, &ulOutBufLen);
  if(ret != ERROR_SUCCESS)
  {
   log_printf("Get Dns server failed");
   return false;
  }
 }
 strcpy(cfg->szDns1,fi->DnsServerList.IpAddress.String);
 IP_ADDR_STRING *pIPAddr = fi->DnsServerList.Next;
 if(pIPAddr != NULL)
  strcpy(cfg->szDns2, pIPAddr->IpAddress.String);
 return false;
}