objective-c - 如何使用 Cocoa 或 Foundation 获取当前连接的网络接口名称？

Question

我需要知道当前连接的网络接口的网络接口名称，如en0、lo0等。

是否有一个 Cocoa/Foundation 函数可以为我提供这些信息？

Answer 1

您可以循环浏览网络接口并获取它们的名称、IP 地址等。

#include <ifaddrs.h>
// you may need to include other headers

struct ifaddrs* interfaces = NULL;
struct ifaddrs* temp_addr = NULL;

// retrieve the current interfaces - returns 0 on success
NSInteger success = getifaddrs(&interfaces);
if (success == 0)
{
    // Loop through linked list of interfaces
    temp_addr = interfaces;
    while (temp_addr != NULL)
    {
      if (temp_addr->ifa_addr->sa_family == AF_INET) // internetwork only
      {
        NSString* name = [NSString stringWithUTF8String:temp_addr->ifa_name];
        NSString* address = [NSString stringWithUTF8String:inet_ntoa(((struct sockaddr_in *)temp_addr->ifa_addr)->sin_addr)];
        NSLog(@"interface name: %@; address: %@", name, address);
      }

      temp_addr = temp_addr->ifa_next;
    }
}

// Free memory
freeifaddrs(interfaces);

上面的结构中还有很多其他的标志和数据，希望你能找到你想要的。

Answer 2

由于 iOS 的工作方式与 OSX 略有不同，我们很幸运地使用了基于 Davyd 的回答的以下代码来查看 iPhone 上所有可用网络接口的名称：（有关 ifaddrs 的完整文档，请参见此处）

#include <ifaddrs.h>

struct ifaddrs* interfaces = NULL;
struct ifaddrs* temp_addr = NULL;

// retrieve the current interfaces - returns 0 on success
NSInteger success = getifaddrs(&interfaces);
if (success == 0)
{
    // Loop through linked list of interfaces
    temp_addr = interfaces;
    while (temp_addr != NULL)
    {
            NSString* name = [NSString stringWithUTF8String:temp_addr->ifa_name];
            NSLog(@"interface name: %@", name);

        temp_addr = temp_addr->ifa_next;
    }
}

// Free memory
freeifaddrs(interfaces);

Answer 3

或者，您也可以利用if_indextoname()来获取可用的接口名称。以下是Swift实现的样子：

public func interfaceNames() -> [String] {

    let MAX_INTERFACES = 128;

    var interfaceNames = [String]()
    let interfaceNamePtr = UnsafeMutablePointer<Int8>.alloc(Int(IF_NAMESIZE))
    for interfaceIndex in 1...MAX_INTERFACES {
        if (if_indextoname(UInt32(interfaceIndex), interfaceNamePtr) != nil){
            if let interfaceName = String.fromCString(interfaceNamePtr) {
                interfaceNames.append(interfaceName)
            }
        } else {
            break
        }
    }

    interfaceNamePtr.dealloc(Int(IF_NAMESIZE))
    return interfaceNames
}

Answer 4

将@ambientlight 的示例代码移植到iOS 13：

public func interfaceNames() -> [String] {

        let MAX_INTERFACES = 128;

        var interfaceNames = [String]()
        let interfaceNamePtr = UnsafeMutablePointer<Int8>.allocate(capacity: Int(Int(IF_NAMESIZE)))
        for interfaceIndex in 1...MAX_INTERFACES {
            if (if_indextoname(UInt32(interfaceIndex), interfaceNamePtr) != nil){
                let interfaceName = String(cString: interfaceNamePtr)
                interfaceNames.append(interfaceName)
            } else {
                break
            }
        }

        interfaceNamePtr.deallocate()
        return interfaceNames
    }

最有可能泄漏内存 - 谨慎使用。

输出：

▿ 20 elements
  - 0 : "lo0"
  - 1 : "pdp_ip0"
  - 2 : "pdp_ip1"
  - 3 : "pdp_ip2"
  - 4 : "pdp_ip3"
  - 5 : "pdp_ip5"
  - 6 : "pdp_ip4"
  - 7 : "pdp_ip6"
  - 8 : "pdp_ip7"
  - 9 : "ap1"
  - 10 : "en0"
  - 11 : "en1"
  - 12 : "en2"
  - 13 : "ipsec0"
  - 14 : "ipsec1"
  - 15 : "ipsec2"
  - 16 : "ipsec3"
  - 17 : "awdl0"
  - 18 : "utun0"
  - 19 : "utun1"