#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <net/if.h> //struct ifreq
#include <sys/ioctl.h> //ioctl、SIOCGIFADDR
#include <sys/socket.h>
#include <netinet/ether.h> //ETH_P_ALL
#include <netpacket/packet.h> //struct sockaddr_ll
#include <pthread.h>
#include <netinet/in.h>
void *send_arp_ask(void *arg);
int main(int argc,char *argv[])
{
//1.创建通信用的原始套接字
int sock_raw_fd = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
//2.创建发送线程
pthread_t tid;
pthread_create(&tid, NULL, (void *)send_arp_ask, (void *)sock_raw_fd);
while(1)
{
//3.接收对方的ARP应答
unsigned char recv_msg[1024] = "";
recvfrom(sock_raw_fd, recv_msg, sizeof(recv_msg), 0, NULL, NULL);
if(recv_msg[21] == 2) //ARP应答
{
char resp_mac[18] = ""; //arp响应的MAC
char resp_ip[16] = ""; //arp响应的IP
sprintf(resp_mac, "%02x:%02x:%02x:%02x:%02x:%02x", \
recv_msg[22],recv_msg[23],recv_msg[24],recv_msg[25],recv_msg[26],recv_msg[27]);
sprintf(resp_ip, "%d.%d.%d.%d", recv_msg[28], recv_msg[29], recv_msg[30], recv_msg[31]);
printf("IP:%s - MAC:%s\n",resp_ip, resp_mac);
}
}
return 0;
}
void *send_arp_ask(void *arg)
{
int i = 0;
int sock_raw_fd = (int)arg;
//1.根据各种协议首部格式构建发送数据报
unsigned char send_msg[1024] = {
//--------------组MAC--------14------
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, //dst_mac: FF:FF:FF:FF:FF:FF
0x00, 0x0c, 0x29, 0x75, 0xa6, 0x51, //src_mac: 00:0c:29:75:a6:51
0x08, 0x06, //类型：0x0806 ARP协议
//--------------组ARP--------28-----
0x00, 0x01, 0x08, 0x00, //硬件类型1(以太网地址),协议类型0x0800(IP)
0x06, 0x04, 0x00, 0x01, //硬件、协议地址分别是6、4，op:(1：arp请求，2：arp应答)
0x00, 0x0c, 0x29, 0x75, 0xa6, 0x51, //发送端的MAC地址
172, 20, 226, 12, //发送端的IP地址
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, //目的MAC地址（由于要获取对方的MAC,所以目的MAC置零）
172, 20, 226, 11 //目的IP地址
};
//2.数据初始化
struct sockaddr_ll sll; //原始套接字地址结构
struct ifreq ethreq; //网络接口地址
strncpy(ethreq.ifr_name, "eth0", IFNAMSIZ); //指定网卡名称
//3.将网络接口赋值给原始套接字地址结构
ioctl(sock_raw_fd, SIOCGIFINDEX, (char *)ðreq);
bzero(&sll, sizeof(sll));
sll.sll_ifindex = ethreq.ifr_ifindex;
//4.本地机的IP
if(!(ioctl(sock_raw_fd, SIOCGIFADDR, (char *)ðreq)))
{
int num = ntohl(((struct sockaddr_in*) (ðreq.ifr_addr))->sin_addr.s_addr);
for(i=0; i<4; i++)
{
send_msg[31-i] = num>>8*i & 0xff; //将发送端的IP地址组包
}
}
//5.获取本地机(eth0)的MAC
if (!(ioctl(sock_raw_fd, SIOCGIFHWADDR, (char *) ðreq)))
{
for(i=0; i<6; i++)
{
//将src_mac、发送端的MAC地址组包
send_msg[22+i] = send_msg[6+i] = (unsigned char) ethreq.ifr_hwaddr.sa_data[i];
}
}
while(1)
{
int i = 0;
int num[4] = {0};
unsigned char input_buf[1024] = "";
//6.获取所要扫描的网段（172.20.226.0）
printf("input_dst_Network:172.20.226.0\n");
fgets(input_buf, sizeof(input_buf), stdin);
sscanf(input_buf, "%d.%d.%d.", &num[0], &num[1], &num[2]//目的IP地址
);
//7.将键盘输入的信息组包
for(i=0;i<4;i++)
send_msg[38+i] = num[i];//将目的IP地址组包
//8.给1~254的IP发送ARP请求
for(i=1; i<255; i++)
{
send_msg[41] = i;
int len = sendto(sock_raw_fd, send_msg, 42, 0 , (struct sockaddr *)&sll, sizeof(sll));
if(len == -1)
{
perror("sendto");
}
}
sleep(1);
}
return;
}
