以前做过获取设备IP地址的功能，但是由于当时代码管理不当，很多代码已经遗失，现在只能重新过一遍，也让自己更有基情激情的学习。网上关于这方面的文章很多，但是找到自己真正需要的却不容易，经过几番周折。终于在著名的stackoverflow上面找到了我想要的答案。
代码如下：

#import <ifaddrs.h>
#import <arpa/inet.h>
#import <net/if.h>

#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 - 获取设备当前网络IP地址
+ (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];
         //筛选出IP地址格式
         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];
            //输出结果
            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;
}

2017年01月11日
很多朋友说这个方法只能获取到内网IP，无法获取公网IP，确实，这边补充下获取公网IP方式。

//方法一：
NSError *error; 
NSURL *ipURL = [NSURL URLWithString:@"http://ifconfig.me/ip"];
NSString *ip = [NSString stringWithContentsOfURL:ipURL encoding:NSUTF8StringEncoding error:&error];
//方法二：个人推荐用这个请求，速度比较快
/*
http://ipof.in/json
http://ipof.in/xml
http://ipof.in/txt
If you want HTTPS you can use the same URLs with https prefix. The advantage being that even if you are on a Wifi you will get the public address.
 */
NSError *error; 
NSURL *ipURL = [NSURL URLWithString:@"http://ipof.in/txt"];
NSString *ip = [NSString stringWithContentsOfURL:ipURL encoding:NSUTF8StringEncoding error:&error];

2017年08月04日
增加部分公开API
1、淘宝API

1. 请求接口（GET）：
http://ip.taobao.com/service/getIpInfo.php?ip=ip地址
2. 响应信息：
（json格式的）国家 、省（自治区或直辖市）、市（县）、运营商
3. 返回数据格式：
{
    "code": 0,
    "data": {
        "country": "中国",
        "country_id": "CN",
        "area": "华南",
        "area_id": "800000",
        "region": "广东省",
        "region_id": "440000",
        "city": "深圳市",
        "city_id": "440300",
        "county": "",
        "county_id": "-1",
        "isp": "电信",
        "isp_id": "100017",
        "ip": "121.35.211.41"
    }
}
其中code的值的含义为，0：成功，1：失败。
4. 访问限制：为了保障服务正常运行，每个用户的访问频率需小于10qps。

2、站长工具API

http://ip.chinaz.com/getip.aspx
返回数据格式：
{ip:'121.35.211.41',address:'广东省深圳市 电信'}

再一次感谢您花费时间阅读这篇文章！

作者：SuperDanny链接：http://www.jianshu.com/p/a74f64f9b72f