ios实现dns解析

NSURL *url = [NSURL URLWithString:@"http://www.example.com"];

NSString *host = url.host;

CFHostRef hostRef = CFHostCreateWithName(kCFAllocatorDefault, (__bridge CFStringRef)host);
CFHostStartInfoResolution(hostRef, kCFHostAddresses, nil);
Boolean success;
CFArrayRef addresses = CFHostGetAddressing(hostRef, &success);
if (success) {
    CFIndex count = CFArrayGetCount(addresses);
    for (CFIndex i = 0; i < count; i++) {
        struct sockaddr *address = (struct sockaddr *)CFDataGetBytePtr(CFArrayGetValueAtIndex(addresses, i));
        if (address != nil) {
            char strBuffer[INET6_ADDRSTRLEN];
            if (inet_ntop(address->sa_family, &(address->sa_data), strBuffer, sizeof(strBuffer))) {
                NSString *ipAddress = [NSString stringWithUTF8String:strBuffer];
                NSLog(@"Resolved IP address: %@", ipAddress);
            }
        }
    }
}