iOS 开发 : Get private IP and port from NSReadStream

Question

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

我可以通过遍历设备接口(interface)获取 IP，但对于端口号，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 为 nil，我不明白为什么。其他人可以吗？

非常感谢任何帮助!

// 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

好的，这现在对我有用了。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;
}