#include <ifaddrs.h>
#include <arpa/inet.h>
#include <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"


+ (NSString *)getIPAddress:(BOOL)preferIPv4 {
    NSArray *searchArray = preferIPv4 ?
    @[iOS_VPN @"/" iP_addr_IPv4, iOS_WiFi @"/" iP_addr_IPv4, iOS_Cellular @"/" iP_addr_IPv4, iOS_VPN @"/" iP_addr_IPv6, iOS_WiFi @"/" iP_addr_IPv6, iOS_Cellular @"/" iP_addr_IPv6] :
    @[iOS_VPN @"/" iP_addr_IPv6, iOS_WiFi @"/" iP_addr_IPv6, iOS_Cellular @"/" iP_addr_IPv6,iOS_VPN @"/" iP_addr_IPv4, iOS_WiFi @"/" iP_addr_IPv4, 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;
}

备注：外网获取ip是通过请求服务器的接口获取，例如淘宝的接口