写C++程序绕过IE的限制：“某些设置由系统管理员进行管理”

公司的电脑，其IE代理都是由“系统管理员”进行统一设置的：Auto Config URL。

打开我的IE10的设置，可以看到如下图样：



我修改了注册表，却发现其实它并未真正生效。

我平时应用的很多软件，因为自带设置代理的功能，所以使用并未受影响，通过用cntlm代理，能干很多事情。但是，iTunes这个软件不一样。它只能使用系统设置的代理。我为了能使用iTunes听那些高质量的Podcast节目，今天在网上找了一些代码，终于成功修改了系统代理，绕过了公司的限制。下面是代码的内容：

// ProxyConnect.cpp : Change system proxy settings programmatically.

#include "stdafx.h"
#include <Windows.h>
#include <WinInet.h>

BOOL QueryConnectionOptions(LPTSTR conn_name)
{
INTERNET_VERSION_INFO Version;
DWORD nSize = sizeof(INTERNET_VERSION_INFO);
InternetQueryOption(NULL, INTERNET_OPTION_VERSION, &Version, &nSize);
printf("[Wininet.dll Version] %d.%d\n", Version.dwMajorVersion, Version.dwMinorVersion);

INTERNET_PER_CONN_OPTION Option[5];							// === The most common useful settings ===
Option[0].dwOption = INTERNET_PER_CONN_AUTOCONFIG_URL;		//1. URL to the automatic configuration script
Option[1].dwOption = INTERNET_PER_CONN_AUTODISCOVERY_FLAGS;	//2. automatic discovery settings (flags: always_detect | use_cached_one | no_cache ...)
Option[2].dwOption = INTERNET_PER_CONN_FLAGS;				//3. connection type (flags: direct | proxy | auto_proxy_url | auto_detect)
Option[3].dwOption = INTERNET_PER_CONN_PROXY_BYPASS;		//4. URLs that do not use the proxy server
Option[4].dwOption = INTERNET_PER_CONN_PROXY_SERVER;		//5. proxy servers

INTERNET_PER_CONN_OPTION_LIST List;		// the list of options for a particular Internet connection
List.dwSize = sizeof(INTERNET_PER_CONN_OPTION_LIST);
List.pszConnection = conn_name;			// the name of the RAS connection; NULL indicates the default or LAN connection, to set or query options on
List.dwOptionCount = sizeof(Option)/sizeof(INTERNET_PER_CONN_OPTION);
List.dwOptionError = 0;
List.pOptions = Option;

nSize = sizeof(INTERNET_PER_CONN_OPTION_LIST);
if(!InternetQueryOption(NULL, INTERNET_OPTION_PER_CONNECTION_OPTION, &List, &nSize))
{
printf("InternetQueryOption failed! (%d)\n", GetLastError());
return FALSE;
}

if(Option[0].Value.pszValue != NULL)
{
printf("[Auto Config URL] %s\n", Option[0].Value.pszValue);
//! default: http://proxy.xxxxxxxx.org/proxy.pac GlobalFree(Option[0].Value.pszValue);
}

if(Option[1].Value.dwValue != 0)
{
printf("[Auto Discovery Settings] %x\n", Option[1].Value.pszValue);
//! default: ZERO
}

if(Option[2].Value.dwValue != 0)
{
printf("[Connection Type] 0x%x\n", Option[2].Value.pszValue);
//! default: 5 ( PROXY_TYPE_AUTO_PROXY_URL | PROXY_TYPE_DIRECT )

if((Option[2].Value.dwValue & PROXY_TYPE_AUTO_PROXY_URL))
printf(" => [PROXY_TYPE] AUTO_PROXY_URL\n");
if((Option[2].Value.dwValue & PROXY_TYPE_AUTO_DETECT))
printf(" => [PROXY_TYPE] AUTO_DETECT\n");
if((Option[2].Value.dwValue & PROXY_TYPE_DIRECT))
printf(" => [PROXY_TYPE] DIRECT\n");
if((Option[2].Value.dwValue & PROXY_TYPE_PROXY))
printf(" => [PROXY_TYPE] PROXY \n");
}

if(Option[3].Value.pszValue != NULL)
{
printf("[Bypass URLs] %s\n", Option[3].Value.pszValue);
//! default: NULL
GlobalFree(Option[3].Value.pszValue);
}

if(Option[4].Value.pszValue != NULL)
{
printf("[Proxy Servers] %s\n", Option[4].Value.pszValue);
//! default: NULL
GlobalFree(Option[4].Value.pszValue);
}

return TRUE;
}

BOOL SetConnectionOptions(LPTSTR conn_name, LPTSTR proxy_full_addr)
{
//conn_name: active connection name.
//proxy_full_addr : eg "210.78.22.87:8000"
INTERNET_PER_CONN_OPTION_LIST list;
list.dwSize = sizeof(list);
list.pszConnection = (LPSTR) conn_name;
list.dwOptionCount = 3;
list.pOptions = new INTERNET_PER_CONN_OPTION[list.dwOptionCount];
if(NULL == list.pOptions)
{
OutputDebugString("failed to allocat memory in SetConnectionOptions()");
return FALSE;
}
// Set flags.
list.pOptions[0].dwOption = INTERNET_PER_CONN_FLAGS;
list.pOptions[0].Value.dwValue = PROXY_TYPE_PROXY;	// PROXY_TYPE_DIRECT | PROXY_TYPE_PROXY

// Set proxy name.
list.pOptions[1].dwOption = INTERNET_PER_CONN_PROXY_SERVER;
list.pOptions[1].Value.pszValue = proxy_full_addr;//"http://proxy:80"

// Set proxy override.
list.pOptions[2].dwOption = INTERNET_PER_CONN_PROXY_BYPASS;
list.pOptions[2].Value.pszValue = _T("local");

// Set the options on the connection. Use NULL to make system-wide affection
BOOL bReturn = InternetSetOption(NULL, INTERNET_OPTION_PER_CONNECTION_OPTION, &list, sizeof(list));
if(!bReturn)
{
printf("InternetSetOption failed! (%d)\n", GetLastError());
}

delete [] list.pOptions;

printf("\n(Modified Options)\n");
QueryConnectionOptions(conn_name);
printf("\n");

InternetSetOption(NULL, INTERNET_OPTION_SETTINGS_CHANGED, NULL, 0);
InternetSetOption(NULL, INTERNET_OPTION_REFRESH , NULL, 0);
return bReturn;
}

BOOL RestoreDefaultSettings(LPTSTR conn_name)
{
INTERNET_PER_CONN_OPTION_LIST list;
list.dwSize = sizeof(list);
list.pszConnection = conn_name;
list.dwOptionCount = 5;
list.pOptions = new INTERNET_PER_CONN_OPTION[list.dwOptionCount];
if(NULL == list.pOptions)
{
OutputDebugString("failed to allocat memory in RestoreDefaultSettings()");
return FALSE;
}

//! 1. Auto Config URL
list.pOptions[0].dwOption = INTERNET_PER_CONN_AUTOCONFIG_URL;
list.pOptions[0].Value.pszValue = _T("http://proxy.xxxxxxxx.org/proxy.pac");
//! 2. Auto Discovery Settings
list.pOptions[1].dwOption = INTERNET_PER_CONN_AUTODISCOVERY_FLAGS;
list.pOptions[1].Value.dwValue = 0;
//! 3. Connection Type
list.pOptions[2].dwOption = INTERNET_PER_CONN_FLAGS;
list.pOptions[2].Value.dwValue = (PROXY_TYPE_AUTO_PROXY_URL | PROXY_TYPE_DIRECT);
//! 4. Bypass URLs
list.pOptions[3].dwOption = INTERNET_PER_CONN_PROXY_BYPASS;
list.pOptions[3].Value.pszValue = NULL;
//! 5. Proxy Servers
list.pOptions[4].dwOption = INTERNET_PER_CONN_PROXY_SERVER;
list.pOptions[4].Value.pszValue = NULL;

// Set the options on the connection. Use NULL to make system-wide affection
BOOL bReturn = InternetSetOption(NULL, INTERNET_OPTION_PER_CONNECTION_OPTION, &list, sizeof(list));
if(!bReturn)
{
printf("InternetSetOption failed! (%d)\n", GetLastError());
}

delete [] list.pOptions;

printf("\n(Modified Options)\n");
QueryConnectionOptions(conn_name);
printf("\n");

InternetSetOption(NULL, INTERNET_OPTION_SETTINGS_CHANGED, NULL, 0);
InternetSetOption(NULL, INTERNET_OPTION_REFRESH , NULL, 0);
return bReturn;
}

int _tmain(int argc, _TCHAR* argv[])
{
    enum Operation
    {
        OP_USE_LOCAL_PROXY    = 0, // use my local CNTLM proxy
        OP_RESTORE_DEFAULT    = 1, // use system default
    } operation = OP_USE_LOCAL_PROXY;

    if (argc > 1)
    {
        if (stricmp(argv[1], _T("-disable"))==0)
            operation = OP_RESTORE_DEFAULT;
        else if (stricmp(argv[1], _T("-enable"))==0)
            operation = OP_USE_LOCAL_PROXY;
    }

    QueryConnectionOptions(NULL);    // NULL, "LAN"
    if (operation == OP_USE_LOCAL_PROXY)
    {
        SetConnectionOptions(NULL, _T("127.0.0.1:5865"));
    }
    else
    {
        RestoreDefaultSettings(NULL);
    }
    return 0;
}

使用时，使用-enable / -disable即可控制代理的开关。注意：一定要牢记默认设置，因为很多软件的使用都依赖它。我发现flash控件就只能通过系统默认的代理下载。