get_local_ip.c

/*=========================================================
* Author         : Junjie Huang
* Email          : [email protected]
* Last modified  : 2016-02-19 09:23
* Filename       : get_local_ip.c
* Description    : 获取本机IP
=========================================================*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <net/if.h>

char * getLocalIP(){
    int MAXINTERFACES=16;
    char * ip = NULL;
    int fd, intrface;
    struct ifreq buf[MAXINTERFACES];
    struct ifconf ifc;
    if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) >= 0){
        ifc.ifc_len = sizeof(buf);
        ifc.ifc_buf = (caddr_t)buf;
        if (!ioctl(fd, SIOCGIFCONF, (char *)&ifc)){
            intrface = ifc.ifc_len / sizeof(struct ifreq);
            while (intrface-- > 0){
                if (!(ioctl (fd, SIOCGIFADDR, (char *) &buf[intrface]))){
                    ip = (inet_ntoa(((struct sockaddr_in*)(&buf[intrface].ifr_addr))->sin_addr));
                    break;
                }
            }
        }
        close(fd);
        return ip;
    }
}