当存在多个网络接口时，可访问性框架在检测接口类型时无法正常工作

Posted 2023-02-24

【中文标题】当存在多个网络接口时，可访问性框架在检测接口类型时无法正常工作

【英文标题】：Reachability framework is not working fine while detecting interface type when there is multiple network interface

【发布时间】：2014-10-20 01:54:21

【问题描述】：

我正在使用可达性框架来检测接口类型。使用单个接口时，它工作正常。但是当使用多个网络接口时，它工作异常。在以下情况下失败 -

假设您有两个网络接口，一个是 WiFi，另一个是蜂窝网络（3G、2G、EDGE 等）。当我尝试检测每个接口的接口类型时，它会为每种情况返回 WiFi。但在仅连接 WiFi 或 3G 接口时工作正常。我已经使用以下代码来检测接口类型 -

 static struct sockaddr_in zeroAddress;
 bzero(&zeroAddress, sizeof(zeroAddress));
 zeroAddress.sin_len = sizeof(zeroAddress);
 zeroAddress.sin_family = AF_INET;

 SCNetworkReachabilityFlags flags;

 AFNetworkInterfaceType  interfaceType = AF_NIC_TYPE_UNKNOWN;

 bool reachable = true;

 UserInfo info;

 static SCNetworkReachabilityRef reachability = SCNetworkReachabilityCreateWithAddress(kCFAllocatorDefault, (const struct sockaddr*)&zeroAddress);


 SCNetworkReachabilityContext context = 0, &info, NULL, NULL, NULL;


 if (SCNetworkReachabilityGetFlags(reachability, &flags))
 

  if ((flags & kSCNetworkReachabilityFlagsReachable) == 0)
  
   // The target host is not reachable.
   reachable = false;

   if ((flags & kSCNetworkReachabilityFlagsReachable) && (flags & kSCNetworkReachabilityFlagsIsDirect))
   
    interfaceType = AF_NIC_TYPE_WIFI;
   
  

  if ( true == reachable  && (flags & kSCNetworkReachabilityFlagsConnectionRequired) == 0)
  
   /*
    If the target host is reachable and no connection is required then we'll assume (for now) that you're on Wi-Fi...
    */

   interfaceType =  AF_NIC_TYPE_WIFI;

  


  if ( true == reachable && (((flags & kSCNetworkReachabilityFlagsConnectionOnDemand ) != 0) ||
           (flags & kSCNetworkReachabilityFlagsConnectionOnTraffic) != 0))
  
   /*
    ... and the connection is on-demand (or on-traffic) if the calling application is using the CFSocketStream or higher APIs...
    */

   if ((flags & kSCNetworkReachabilityFlagsInterventionRequired) == 0)
   
    /*
     ... and no [user] intervention is needed...
     */
    interfaceType = AF_NIC_TYPE_WIFI;
   
  

  if ( true == reachable && (flags & kSCNetworkReachabilityFlagsIsWWAN) == kSCNetworkReachabilityFlagsIsWWAN)
  
   /*
    ... but WWAN connections are OK if the calling application is using the CFNetwork APIs.
    */
   interfaceType = AF_NIC_TYPE_CELLULAR;
  
 

调试后我看到它进入第二个块并检测到接口类型WiFi。谁能告诉我如何正确确定所有网络接口的类型。

注意：我在 C++ 库解决方案中使用上述代码，这是一个跨平台库。

【参考方案1】：

此问题已修复。发布它以便用户可以获得帮助。主要问题是我在 zeroAddress 结构中传递了 NULL。在结构中分配我的网络接口地址后，它通过了所有案例并正确确定了网络接口类型。