iOS开发：从NSReadStream获取私有IP和端口

Question

我正在为iOS开发一个应用程序。在我的应用程序中有一个到服务器的TCP连接，通过NSStreams实现。现在我需要连接使用的端口，这会产生一些问题。

我可以通过遍历设备的接口获取IP，但对于portnumber我必须从套接字获取信息。在下面的代码中，我尝试从我的工作中获取套接字并打开NSInputStream _readstream。问题是，CFSocketCopyAddress是零，我不明白为什么。别人可以吗？

任何帮助非常感谢！

// Initializing some variables we need 
CFSocketContext context; 
memset(&context, 0, sizeof(context)); 
context.info = (__bridge void*)self; 
NSString *property = @"kCFStreamPropertySocketNativeHandle"; 

// Get hands on the used socket via the socket native handle 
CFSocketNativeHandle *socketNativeHandle = (CFSocketNativeHandle*)CFReadStreamCopyProperty((__bridge CFReadStreamRef)(_readStream), (__bridge CFStringRef)(property)); 
CFSocketRef cfSocket = CFSocketCreateWithNative(NULL, *socketNativeHandle, kCFSocketNoCallBack, nil, &context); 

// Ask the socket for the address information 
CFDataRef    dataRef = CFSocketCopyAddress(cfSocket);      // dataRef is always nil :(
struct sockaddr_in  *sockaddr = (struct sockaddr_in*)CFDataGetBytePtr(dataRef); 

int portnumber = sockaddr->sin_port; 

Answer 1

好吧，这现在对我有用。也许我可以帮助来自谷歌或其他地方的人......

- (NSNumber*) getPortnumber{ 
    int    port  = -1; 

    CFSocketContext context; 
    memset(&context, 0, sizeof(context)); 
    context.info = (__bridge void*)self; 

    // Get Socket native handle from existing stream 
    CFDataRef socketData = CFWriteStreamCopyProperty((__bridge CFWriteStreamRef)(_writeStream), kCFStreamPropertySocketNativeHandle); 

    // Get the native handle 
    CFSocketNativeHandle handle; 
    CFDataGetBytes(socketData, CFRangeMake(0, sizeof(CFSocketNativeHandle)), &handle); 

    // Get the socket 
    CFSocketRef cfSocket = CFSocketCreateWithNative(NULL, handle, kCFSocketNoCallBack, nil, &context); 

    // CFSocketCopyAddress will return the address of the socket 
    CFDataRef    dataRef = CFSocketCopyAddress(cfSocket); 
    struct sockaddr_in  *sockaddr = (struct sockaddr_in*)CFDataGetBytePtr(dataRef); 

    // Get the port from the address information 
    port = sockaddr->sin_port; 

    // Output Objective-C friendly =) 
    NSNumber *portnr = [NSNumber numberWithInt:port]; 
    return portnr; 
}