setproxy.go

package main

import (
	"fmt"
	"syscall"
	"unsafe"
)

const (
	INTERNET_PER_CONN_FLAGS               = 1
	INTERNET_PER_CONN_PROXY_SERVER        = 2
	INTERNET_PER_CONN_PROXY_BYPASS        = 3
	INTERNET_OPTION_REFRESH               = 37
	INTERNET_OPTION_SETTINGS_CHANGED      = 39
	INTERNET_OPTION_PER_CONNECTION_OPTION = 75
)

/*
typedef struct {
  DWORD dwOption;
  union {
    DWORD    dwValue;
    LPSTR    pszValue;
    FILETIME ftValue;
  } Value;
} INTERNET_PER_CONN_OPTIONA, *LPINTERNET_PER_CONN_OPTIONA;

typedef struct _FILETIME {
  DWORD dwLowDateTime;
  DWORD dwHighDateTime;
} FILETIME, *PFILETIME, *LPFILETIME;
*/
type INTERNET_PER_CONN_OPTION struct {
	dwOption uint32
	dwValue  uint64 // 注意 32位 和 64位 struct 和 union 内存对齐
}

type INTERNET_PER_CONN_OPTION_LIST struct {
	dwSize        uint32
	pszConnection *uint16
	dwOptionCount uint32
	dwOptionError uint32
	pOptions      uintptr
}

//格式：ip:port 127.0.0.1:7890
func SetProxy(proxy string) error {
	winInet, err := syscall.LoadLibrary("Wininet.dll")
	if err != nil {
		return fmt.Errorf(fmt.Sprintf("LoadLibrary Wininet.dll Error: %s", err))
	}
	InternetSetOptionW, err := syscall.GetProcAddress(winInet, "InternetSetOptionW")
	if err != nil {
		return fmt.Errorf(fmt.Sprintf("GetProcAddress InternetQueryOptionW Error: %s", err))
	}

	options := [3]INTERNET_PER_CONN_OPTION{}
	options[0].dwOption = INTERNET_PER_CONN_FLAGS
	if proxy == "" {
		options[0].dwValue = 1
	} else {
		options[0].dwValue = 2
	}
	options[1].dwOption = INTERNET_PER_CONN_PROXY_SERVER
	options[1].dwValue = uint64(uintptr(unsafe.Pointer(syscall.StringToUTF16Ptr(proxy))))
	options[2].dwOption = INTERNET_PER_CONN_PROXY_BYPASS
	options[2].dwValue = uint64(uintptr(unsafe.Pointer(syscall.StringToUTF16Ptr("localhost;127.*;10.*;172.16.*;172.17.*;172.18.*;172.19.*;172.20.*;172.21.*;172.22.*;172.23.*;172.24.*;172.25.*;172.26.*;172.27.*;172.28.*;172.29.*;172.30.*;172.31.*;172.32.*;192.168.*"))))

	list := INTERNET_PER_CONN_OPTION_LIST{}
	list.dwSize = uint32(unsafe.Sizeof(list))
	list.pszConnection = nil
	list.dwOptionCount = 3
	list.dwOptionError = 0
	list.pOptions = uintptr(unsafe.Pointer(&options))

	// https://www.cnpython.com/qa/361707
	callInternetOptionW := func(dwOption uintptr, lpBuffer uintptr, dwBufferLength uintptr) error {
		r1, _, err := syscall.Syscall6(InternetSetOptionW, 4, 0, dwOption, lpBuffer, dwBufferLength, 0, 0)
		if r1 != 1 {
			return err
		}
		return nil
	}

	err = callInternetOptionW(INTERNET_OPTION_PER_CONNECTION_OPTION, uintptr(unsafe.Pointer(&list)), uintptr(unsafe.Sizeof(list)))
	if err != nil {
		return fmt.Errorf("INTERNET_OPTION_PER_CONNECTION_OPTION Error: %s", err)
	}
	err = callInternetOptionW(INTERNET_OPTION_SETTINGS_CHANGED, 0, 0)
	if err != nil {
		return fmt.Errorf("INTERNET_OPTION_SETTINGS_CHANGED Error: %s", err)
	}
	err = callInternetOptionW(INTERNET_OPTION_REFRESH, 0, 0)
	if err != nil {
		return fmt.Errorf("INTERNET_OPTION_REFRESH Error: %s", err)
	}
	return nil
}

// func main() {
// 	//proxy := flag.String("p", "127.0.0.1:10809", "(-p host:port 设置并启用代理服务器, -p c 取消设置")
// 	//flag.Parse()
// 	if proxy == "c" {
// 		if err := SetProxy(""); err == nil {
// 			fmt.Println("取消代理设置成功!")
// 		} else {
// 			fmt.Printf("取消代理设置失败: %s\n", err)
// 		}
// 	} else {
// 		if err := SetProxy(proxy); err == nil {
// 			fmt.Printf("设置代理服务器: %s 成功!\n", *proxy)
// 		} else {
// 			fmt.Printf("设置代理服务器: %s 失败, : %s\n", *proxy, err)
// 		}
// 	}
// }