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#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <netdb.h>
#include <sys/types.h>
#include <sys/param.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <net/if.h>
#include <netinet/in.h>
#include <net/if_arp.h>
#include <net/ethernet.h>
#define MAXINTERFACES 16
int getpacket(int fd);
int sendpacket(int fd, char *mac, unsigned int network, unsigned ipaddr, unsigned int range);
struct arpheader
{
unsigned short int ar_hrd; /* Format of hardware address. */
unsigned short int ar_pro; /* Format of protocol address. */
unsigned char ar_hln; /* Length of hardware address. */
unsigned char ar_pln; /* Length of protocol address. */
unsigned short int ar_op; /* ARP opcode (command). */
unsigned char __ar_sha[6]; /* Sender hardware address. */
unsigned char __ar_sip[4]; /* Sender IP address. */
unsigned char __ar_tha[6]; /* Target hardware address. */
unsigned char __ar_tip[4]; /* Target IP address. */
};
int flag = 0;
int main(int argc, char *argv[]){
int fd;
int intnum, i, j;
int pid;
struct ifconf ifc;
struct ifreq buf[MAXINTERFACES];
struct in_addr ipaddr, netmask;
unsigned int network, range;
char mac[6];
int stat;
if((argc == 2)&&(strcmp(argv[1], "-s") == 0)){
flag = 1;
}
if((fd = socket(AF_INET, SOCK_PACKET, htons(ETHERTYPE_ARP))) == -1){
fprintf(stderr, "socket init failed: %s \n", strerror(errno));
exit(1);
}
ifc.ifc_len = sizeof(buf);
ifc.ifc_buf = (caddr_t)buf;
if(ioctl (fd, SIOCGIFCONF, (char *) &ifc) == -1){
fprintf(stderr, "ioctl ifconf failed: %s \n", strerror(errno));
exit(1);
}
intnum = ifc.ifc_len / sizeof (struct ifreq);
//printf("interface num is intrface=%d\n\n\n",intrface);
i = 0;
fprintf(stdout, "select follow net device:\n");
while(i < intnum){
fprintf (stdout, "%d. net device %s: ", i+1, buf[i].ifr_name);
if(ioctl(fd, SIOCGIFADDR, (char *) &buf[i]) == -1){
fprintf(stderr, "ioctl ifaddr failed: %s \n", strerror(errno));
exit(1);
}
fprintf(stdout, "%s\n", (char*)inet_ntoa(((struct sockaddr_in*)(&buf[i].ifr_addr))->sin_addr));
i++;
}
fprintf(stdout, "please select one net device[1-%d]:", intnum);
fscanf(stdin, "%d", &j);
if(ioctl(fd, SIOCGIFADDR, (char *) &buf[j-1]) == -1){
fprintf(stderr, "ioctl ifaddr failed: %s \n", strerror(errno));
exit(1);
}
memcpy(&ipaddr, &(((struct sockaddr_in*)(&buf[j-1].ifr_addr))->sin_addr), sizeof(struct in_addr));
if(ioctl(fd, SIOCGIFNETMASK, (char *) &buf[j-1]) == -1){
fprintf(stderr, "ioctl ifaddr failed: %s \n", strerror(errno));
exit(1);
}
memcpy(&netmask, &(((struct sockaddr_in*)(&buf[j-1].ifr_addr))->sin_addr), sizeof(struct in_addr));
if (ioctl (fd, SIOCGIFHWADDR, (char *) &buf[j-1]) == -1){
fprintf(stderr, "ioctl hwaddr failed: %s \n", strerror(errno));
exit(1);
}
memcpy(mac, buf[j-1].ifr_hwaddr.sa_data, 6);
network = (ntohl(ipaddr.s_addr) & ntohl(netmask.s_addr));
range = ~ntohl(netmask.s_addr);
pid = fork();
if(pid == 0){
getpacket(fd);
}else{
sendpacket(fd, mac, network, ipaddr.s_addr, range);
}
wait(&stat);
return 0;
}
int getpacket(int fd){
struct sockaddr addr;
char buffer[1500];
int recv_byte, len;
struct ether_header eth_hdr;
struct arpheader arp_hdr;
bzero(&addr, sizeof(addr));
len = sizeof(addr);
struct in_addr ipaddr;
fd_set fds;
struct timeval timeout;
FD_ZERO(&fds);
FD_SET(fd, &fds);
timeout.tv_sec = 3;
timeout.tv_usec = 0;
while(1){
select(fd+1, &fds, NULL, NULL, &timeout);
if(FD_ISSET(fd, &fds)){
if((recv_byte = recvfrom(fd, buffer, 1500, 0, &addr, (socklen_t*)&len)) == -1){
fprintf(stderr, "recvfrom failed: %s \n", strerror(errno));
exit(1);
}
memcpy(e_hdr, buffer, sizeof(eth_hdr));
memcpy(&arp_hdr, buffer+sizeof(eth_hdr), sizeof(arp_hdr));
if(arp_hdr.ar_op == ntohs(2)){
memcpy(&ipaddr, arp_hdr.__ar_sip, 4);
if(flag){
fprintf(stdout, "%s, host on line\n", (char*)inet_ntoa(ipaddr));
}else{
fprintf(stdout, "%s, network device may be set promisc\n", (char*)inet_ntoa(ipaddr));
}
}
}else{
break;
}
}
close(fd);
return 0;
}
int sendpacket(int fd, char *mac, unsigned int network, unsigned ipaddr, unsigned int range){
struct ether_header eth_hdr;
struct arpheader arp_hdr;
int i;
struct sockaddr addr;
char buffer[255];
int ip;
if(flag){
memcpy(e_hdr.ether_dhost, "\xff\xff\xff\xff\xff\xff", 6);
}else{
memcpy(e_hdr.ether_dhost, "\xff\xff\xff\xff\xff\xfe", 6);
//memcpy(e_hdr.ether_dhost, "\x01\x00\x5e\x00\x00\x01", 6);
}
memcpy(e_hdr.ether_shost, mac, 6);
eth_hdr.ether_type = htons(ETHERTYPE_ARP);
arp_hdr.ar_hrd = htons(1);
arp_hdr.ar_pro = htons(0x0800);
arp_hdr.ar_hln = 6;
arp_hdr.ar_pln = 4;
arp_hdr.ar_op = htons(1);
memcpy(arp_hdr.__ar_sha, mac, 6);
memcpy(arp_hdr.__ar_sip, &ipaddr, 4);
memset(arp_hdr.__ar_tha, 0, 6);
bzero(&addr, sizeof(addr));
strcpy(addr.sa_data, "eth0" );
i = 1;
while(i < range){
ip = htonl(network + i);
memcpy(arp_hdr.__ar_tip, &ip, 4);
memcpy(buffer, e_hdr, sizeof(eth_hdr));
memcpy(buffer+sizeof(eth_hdr), &arp_hdr, sizeof(arp_hdr));
if(sendto(fd, buffer, sizeof(eth_hdr)+sizeof(arp_hdr), 0, (struct sockaddr*)&addr, sizeof(addr)) == -1){
fprintf(stderr, "sendto failed: %s, \n", strerror(errno));
exit(1);
}
i++;
usleep(1000);
}
close(fd);
return 0;
}
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