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#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <net/if.h>
#include <arpa/inet.h>
#define ETH_P_ARP 0x0806
#define MAX_PACK_LEN 2000
#define ETHER_HEADER_LEN 14
#define ARPREQUEST 0x0001
#define ARPREPLY 0x0002
#define perr(s) fprintf(stderr,s)
struct arp_struct
{
u_char dst_mac[6];
u_char src_mac[6];
u_short pkt_type;
u_short hw_type;
u_short pro_type;
u_char hw_len;
u_char pro_len;
u_short arp_op;
u_char sender_eth[6];
u_char sender_ip[4];
u_char target_eth[6];
u_char target_ip[4];
};
union
{
u_char full_packet[MAX_PACK_LEN];
struct arp_struct arp_pkt;
}a;
#define full_packet a.full_packet
#define arp_pkt a.arp_pkt
int CheckIPCollision(char *ipaddr)
{
int rec=0;
int ret=0;
int len=0, from_len=0, rsflags=0;
u_int8_t myMAC[6]; //6bytes for mac address 4bytes for ip address
u_int32_t myIP, myNETMASK, myBROADCAST, ip, sip,kip;
char devname[10] = {0};
fd_set fdset;
int retval = 0;
struct timeval tmout;
tmout.tv_sec = 0;
tmout.tv_usec = 15000;
struct ifreq if_data;
struct sockaddr from;
struct in_addr testaddr;
if (NULL == ipaddr){
return -1;
}
ret= inet_aton(ipaddr,&testaddr);
if(ret==0){
return -1;
}
/*取出类型为无符号长整型的s_addr元素，即为ip对应的32位二进制数*/
kip=testaddr.s_addr;
/*权限检查,也可以不进行*/
if(getuid() != 0){
return -1;
}
if((rec = socket(AF_INET, SOCK_PACKET, htons(ETH_P_ARP))) < 0){
return -1;
}
#ifdef EMBED
if (0 == system("ifconfig br0 > /tmp/dev")){
strcpy (devname, "br0");
}
else{
strcpy (devname, "eth1");
}
#else
strcpy (devname, "eth0");
#endif
strcpy (if_data.ifr_name, devname);
if(ioctl(rec, SIOCGIFHWADDR, &if_data) < 0) {
close(rec);return -1;
}
memcpy(myMAC,if_data.ifr_hwaddr.sa_data, 6);
if(ioctl(rec, SIOCGIFADDR, &if_data) < 0){
close(rec);return -1;
}
memcpy((void *)&myIP, (void *)&if_data.ifr_addr.sa_data + 2, 4);
if(ioctl (rec, SIOCGIFNETMASK, &if_data) < 0){
close(rec);return -1;
}
memcpy((void *) &ip, (void *) &if_data.ifr_netmask.sa_data + 2, 4);
myNETMASK = ntohl (ip);
if (ioctl (rec, SIOCGIFBRDADDR, &if_data) < 0) {
close(rec);return -1;
}
memcpy ((void *) &ip, (void *) &if_data.ifr_broadaddr.sa_data + 2, 4);
myBROADCAST = ntohl (ip);
if ((rsflags = fcntl (rec, F_GETFL)) == -1){
close(rec);return -1;
}
if (fcntl (rec, F_SETFL, rsflags | O_NONBLOCK) == -1) {
close(rec);return -1;
}
bzero (full_packet, MAX_PACK_LEN);
memcpy (arp_pkt.dst_mac, "\xff\xff\xff\xff\xff\xff", 6);
memcpy (arp_pkt.src_mac, myMAC, 6);
arp_pkt.pkt_type = htons (ETH_P_ARP);
arp_pkt.hw_type = htons (0x0001);
arp_pkt.hw_len = 6;
arp_pkt.pro_type = htons (0x0800);
arp_pkt.pro_len = 4;
arp_pkt.arp_op = htons (ARPREQUEST);
memcpy (arp_pkt.sender_eth,myMAC, 6);
memcpy (arp_pkt.sender_ip, &myIP, 4);
memcpy (arp_pkt.target_eth, "\xff\xff\xff\xff\xff\xff", 6);
ip=kip;
memcpy (arp_pkt.target_ip, &ip, 4);
strcpy (from.sa_data,devname);
from.sa_family = 1;
len =sendto (rec, full_packet, sizeof (struct arp_struct), 0, &from, sizeof(from));
if(0>=len){
close(rec);return -1;
}
FD_ZERO(&fdset);
FD_SET(rec, &fdset);
retval = select(rec+1,&fdset,NULL,NULL,&tmout);
if (0 >= retval){
close(rec);return 1;
}
len = recvfrom (rec, full_packet, MAX_PACK_LEN, 0, &from, &from_len);
memcpy (&ip, arp_pkt.target_ip, 4);
memcpy (&sip, arp_pkt.sender_ip, 4);
//have receive data suggest the IP has been used by some mac
if(len>ETHER_HEADER_LEN){
if(sip == inet_addr(ipaddr))
{
close(rec);
return 0;
}
}
close(rec);
return 1;
}
int main(int argc, char *argv[])
{
char * ip;
int i,j;
int count= 0;
struct in_addr ina;
if(argc!=2)
{
fprintf(stderr,"bad argument\nipcheck [networkaddress]\n");
exit(-1);
}
ip = argv[1];
ina.s_addr = inet_addr(ip);
ina.s_addr = ntohl(ina.s_addr);
ina.s_addr &=0xffffff00;
ina.s_addr +=1;
ina.s_addr = htonl(ina.s_addr);
printf("starting from %s\n",inet_ntoa(ina));
for(j=0;j<254;j++)
{
ip = inet_ntoa(ina);
i = CheckIPCollision(ip);
if(1 == i)
{
//printf("IP: %s is not in use now.\n",ip);
}
else if(-1 == i)
printf("Error in arp process check if you have root privilege\n");
else
{
count ++;
int i;
printf("[%02d]IP: %s\tis in use! ",count,ip);
printf("[MAC Address]: ");
for(i=0;i<5;i++)
printf("%02x:",arp_pkt.sender_eth[i]);
printf("%02x\n",arp_pkt.sender_eth[5]);
}
ina.s_addr = ntohl(ina.s_addr);
ina.s_addr +=1;
ina.s_addr = htonl(ina.s_addr);
//binip++;
}
if(- i)
{
printf("-------------IP checking Statistics---------------\n");
printf("Total %d IPs are in use in current network\n",count);
}
return 0;
}
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