objective-c - iOS获取IP地址问题

Question

项目需要采集设备信息，从 stackOverFlow 上找到的方法是

+ (NSString *)getIPAddress:(BOOL)preferIPv4
{
    NSArray *searchArray = preferIPv4 ?
    @[ /*IOS_VPN @"/" IP_ADDR_IPv4, IOS_VPN @"/" IP_ADDR_IPv6,*/ IOS_WIFI @"/" IP_ADDR_IPv4, IOS_WIFI @"/" IP_ADDR_IPv6, IOS_CELLULAR @"/" IP_ADDR_IPv4, IOS_CELLULAR @"/" IP_ADDR_IPv6 ] :
    @[ /*IOS_VPN @"/" IP_ADDR_IPv6, IOS_VPN @"/" IP_ADDR_IPv4,*/ IOS_WIFI @"/" IP_ADDR_IPv6, IOS_WIFI @"/" IP_ADDR_IPv4, IOS_CELLULAR @"/" IP_ADDR_IPv6, IOS_CELLULAR @"/" IP_ADDR_IPv4 ] ;
    
    NSDictionary *addresses = [self getIPAddresses];
    NSLog(@"addresses: %@", addresses);
    
    __block NSString *address;
    [searchArray enumerateObjectsUsingBlock:^(NSString *key, NSUInteger idx, BOOL *stop)
     {
         address = addresses[key];
         if(address) *stop = YES;
     } ];
    return address ? address : @"0.0.0.0";
}

+ (NSDictionary *)getIPAddresses
{
    NSMutableDictionary *addresses = [NSMutableDictionary dictionaryWithCapacity:8];
    
    // retrieve the current interfaces - returns 0 on success
    struct ifaddrs *interfaces;
    if(!getifaddrs(&interfaces)) {
        // Loop through linked list of interfaces
        struct ifaddrs *interface;
        for(interface=interfaces; interface; interface=interface->ifa_next) {
            if(!(interface->ifa_flags & IFF_UP) /* || (interface->ifa_flags & IFF_LOOPBACK) */ ) {
                continue; // deeply nested code harder to read
            }
            const struct sockaddr_in *addr = (const struct sockaddr_in*)interface->ifa_addr;
            char addrBuf[ MAX(INET_ADDRSTRLEN, INET6_ADDRSTRLEN) ];
            if(addr && (addr->sin_family==AF_INET || addr->sin_family==AF_INET6)) {
                NSString *name = [NSString stringWithUTF8String:interface->ifa_name];
                NSString *type;
                if(addr->sin_family == AF_INET) {
                    if(inet_ntop(AF_INET, &addr->sin_addr, addrBuf, INET_ADDRSTRLEN)) {
                        type = IP_ADDR_IPv4;
                    }
                } else {
                    const struct sockaddr_in6 *addr6 = (const struct sockaddr_in6*)interface->ifa_addr;
                    if(inet_ntop(AF_INET6, &addr6->sin6_addr, addrBuf, INET6_ADDRSTRLEN)) {
                        type = IP_ADDR_IPv6;
                    }
                }
                if(type) {
                    NSString *key = [NSString stringWithFormat:@"%@/%@", name, type];
                    addresses[key] = [NSString stringWithUTF8String:addrBuf];
                }
            }
        }
        // Free memory
        freeifaddrs(interfaces);
    }
    return [addresses count] ? addresses : nil;
}

获得到的ip地址是192.168.1.100,但是手机直接在百度上得到的IP地址是218.65.52.142（这个是对的），前面是local address?

stackOverFlow地址：链接描述

wifi 和4g的情况是一样的，有能获取后面地址的方法吗？

Answer 1

If you only collect IP information, provide an interface directly on the server. When the client requests, the server can record the client’s real IP

Answer 2

Quote ALNetwork
and then NSString *IPAddress = [ALNetwork externalIPAddress];
you can get it.
The method used by this class is actually to obtain the IP by requesting other people's servers. (http://www.dyndns.org/cgi-bin...

// Credits to Shmoopi LLC, SystemServiceDemo
// Get the External IP Address
+ (NSString *)externalIPAddress {
    // Check if we have an internet connection then try to get the External IP Address
    if (![self connectedViaWiFi] && ![self connectedVia3G]) {
        // Not connected to anything, return nil
        return nil;
    }
    
    // Get the external IP Address based on dynsns.org
    NSError *error = nil;
    NSString *theIpHtml = [NSString stringWithContentsOfURL:[NSURL URLWithString:@"http://www.dyndns.org/cgi-bin/check_ip.cgi"]
                                                   encoding:NSUTF8StringEncoding
                                                      error:&error];
    if (!error) {
        NSUInteger  an_Integer;
        NSArray *ipItemsArray;
        NSString *externalIP;
        NSScanner *theScanner;
        NSString *text = nil;
        
        theScanner = [NSScanner scannerWithString:theIpHtml];
        
        while ([theScanner isAtEnd] == NO) {
            
            // find start of tag
            [theScanner scanUpToString:@"<" intoString:NULL] ;
            
            // find end of tag
            [theScanner scanUpToString:@">" intoString:&text] ;
            
            // replace the found tag with a space
            //(you can filter multi-spaces out later if you wish)
            theIpHtml = [theIpHtml stringByReplacingOccurrencesOfString:
                         [ NSString stringWithFormat:@"%@>", text]
                                                             withString:@" "] ;
            ipItemsArray = [theIpHtml  componentsSeparatedByString:@" "];
            an_Integer = [ipItemsArray indexOfObject:@"Address:"];
            externalIP =[ipItemsArray objectAtIndex:++an_Integer];
        }
        // Check that you get something back
        if (externalIP == nil || externalIP.length <= 0) {
            // Error, no address found
            return nil;
        }
        // Return External IP
        return externalIP;
    } else {
        // Error, no address found
        return nil;
    }
}

I built a test project based on this answer from Stack Overflow: Objective C - How to get the public IP address of the device
Github: Github iOS-GetIP
You can download it and try it out.
That ALNetwork refers to a class that checks the network connection status. I commented it out. You can add it if needed.