iOS 获取客户端的IP地址

#import <ifaddrs.h>

#import <arpa/inet.h>

- (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;

}