#include <sys/ioctl.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <math.h>
#include <net/if.h>
#include <stdio.h>
#include <assert.h>
#include <ctype.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "frag_common.h"

/* this function is copy from other system. */
/*
static char *memcasemem(const char *strsrc,int len1,const char *substr,int len2)
{
		
	char *p1,*p2,*pend;
	char *p;
	char *substrS;
	int i,lenth;

	if((strsrc==NULL)||substr==NULL)
		return NULL;
	if(len1<len2) return NULL;

	lenth=len2;
	substrS=(char *)malloc(sizeof(char)*(lenth+1));
	if(substrS==NULL)
		return NULL;
	for(i=0;i<lenth;i++)
	{
		substrS[i]=tolower(*(substr+i));
	}
	substrS[lenth]=0;

	lenth=len1;
	pend =(char *)strsrc + lenth;
	for(p1 =(char *) strsrc; p1 != pend;p1++)
	{
		for(p2 = p1,p = substrS;*p != '\0'&& p2 != pend;p++,p2++)
		{
			if(tolower(*p2) != *p)
				break;
		}
		if(*p == '\0')
		{
			free(substrS);
			return p1;
		}
	}

	free(substrS);
	return NULL;
}	
*/
unsigned int get_ip_by_ifname(const char *ifname)
 {
	 int sockfd;
	 struct ifreq ifr;
	 unsigned int ip;
 
	 sockfd = socket(AF_INET, SOCK_DGRAM, 0);
	 if (-1 == sockfd) 
	 {
		 goto error;
	 }
 
	 strcpy(ifr.ifr_name,ifname); 
	 if (ioctl(sockfd, SIOCGIFADDR, &ifr) < 0) 
	 {
		 goto error;
	 }
 
	 ip = ((struct sockaddr_in*)&(ifr.ifr_addr))->sin_addr.s_addr;
	 close(sockfd);
	 return ip;
 
 error:
	 close(sockfd);
	 return INADDR_NONE;
 }