iOS에서 디바이스 IP 주소 가져오기

프로젝트에서 iOS 디바이스의 IP 주소를 가져올 때는 다음 두 가지 방법이 사용됩니다.
1) 첫 번째는 간단하지만, 장치가 와이파이에 연결되어 있을 때만 IP 주소를 얻을 수 있으며, 만약 장치가 데이터를 사용한다면 안 된다.코드는 다음과 같습니다.

#import 
#import 



// Get IP Address
- (NSString *)getIPAddress {    
    NSString *address = @"error";
    struct ifaddrs *interfaces = NULL;
    struct ifaddrs *temp_addr = NULL;
    int success = 0;
    // retrieve the current interfaces - returns 0 on success
    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) {
                // Check if interface is en0 which is the wifi connection on the iPhone
                if([[NSString stringWithUTF8String:temp_addr->ifa_name] isEqualToString:@"en0"]) {
                    // Get NSString from C String
                    address = [NSString stringWithUTF8String:inet_ntoa(((struct sockaddr_in *)temp_addr->ifa_addr)->sin_addr)];               
                }
            }
            temp_addr = temp_addr->ifa_next;
        }
    }
    // Free memory
    freeifaddrs(interfaces);
    return address;

} 

2) 두 번째 방법은 WIFI든 트래픽이든 IP 주소를 얻을 수 있는 일반적인 방법으로, 코드는 다음과 같습니다.

#import 
#import 
#import 

#define IOS_CELLULAR    @"pdp_ip0"
#define IOS_WIFI        @"en0"
#define IOS_VPN         @"utun0"
#define IP_ADDR_IPv4    @"ipv4"
#define IP_ADDR_IPv6    @"ipv6"


#pragma mark -         IP  
+ (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];
         //   IP    
         if([self isValidatIP:address]) *stop = YES;
     } ];
    return address ? address : @"0.0.0.0";
}

+ (BOOL)isValidatIP:(NSString *)ipAddress {
    if (ipAddress.length == 0) {
        return NO;
    }
    NSString *urlRegEx = @"^([01]?\\d\\d?|2[0-4]\\d|25[0-5])\\."
    "([01]?\\d\\d?|2[0-4]\\d|25[0-5])\\."
    "([01]?\\d\\d?|2[0-4]\\d|25[0-5])\\."
    "([01]?\\d\\d?|2[0-4]\\d|25[0-5])$";
    
    NSError *error;
    NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:urlRegEx options:0 error:&error];
    
    if (regex != nil) {
        NSTextCheckingResult *firstMatch=[regex firstMatchInString:ipAddress options:0 range:NSMakeRange(0, [ipAddress length])];
        
        if (firstMatch) {
            NSRange resultRange = [firstMatch rangeAtIndex:0];
            NSString *result=[ipAddress substringWithRange:resultRange];
            //    
            NSLog(@"%@",result);
            return YES;
        }
    }
    return NO;
}

+ (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;
}

Reference
[1] http://superdanny.link/2016/01/27/iOS-get-device-ip-address/index.html
[2] http://stackoverflow.com/questions/7072989/iphone-ipad-osx-how-to-get-my-ip-address-programmatically