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<td width="68%" background="DDl_back2.jpg" height="44"><big><big><font face="黑体"><p align="center">               ● UNIX网络编程                       (BM: clown)                </font></big></big></td></tr>
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<tr><td width="100%" colspan="2" height="100" align="center" valign="top"><br><p align="center">[<a href="index.htm">回到开始</a>][<a href="54.htm">上一层</a>][<a href="89.htm">下一篇</a>]
<hr><p align="left"><small>发信人: clown (梧桐叶), 信区: UNP <br>

标  题: 发送arp广播的程序 <br>

发信站: UNIX编程 (2001年09月27日17:18:42 星期四), 站内信件 <br>

  <br>

//将自己的ip和arp广播出去，可以抢ip地址哟！ <br>

  <br>

//send an arp broadcast <br>

#include <stdio.h> <br>

#include <stdlib.h> <br>

#include <ctype.h> <br>

#include <netdb.h> <br>

#include <sys/ioctl.h> <br>

#include <sys/types.h> <br>

#include <sys/socket.h> <br>

#include <net/if.h> <br>

#include <netinet/in.h> <br>

#include <arpa/inet.h> <br>

#include <net/if_arp.h> <br>

#include <net/ethernet.h> <br>

#include <string.h> <br>

#include <errno.h> <br>

  <br>

#define LINELENGTH 32 <br>



#define ETH_HW_ADDR_LEN 6 <br>

#define IP_ADDR_LEN 4 <br>

#define DEV_LEN 10 <br>

  <br>

struct arp_packet <br>

{ <br>

    u_char  targ_hw_addr[ETH_HW_ADDR_LEN]; <br>

    u_char  src_hw_addr[ETH_HW_ADDR_LEN]; <br>

    u_short frame_type; <br>

  <br>

    u_short hw_type; <br>

    u_short prot_type; <br>

    u_char  hw_addr_size; <br>

    u_char  prot_addr_size; <br>

    u_short op; <br>

  <br>

    u_char  sndr_hw_addr[ETH_HW_ADDR_LEN]; <br>

    u_char  sndr_ip_addr[IP_ADDR_LEN]; <br>

    u_char  rcpt_hw_addr[ETH_HW_ADDR_LEN]; <br>

    u_char  rcpt_ip_addr[IP_ADDR_LEN]; <br>

  <br>

    u_char  padding[18]; //'cos the minimum ether packet length is 60 bytes. <br>



  <br>

}; <br>

  <br>

struct ifconf ifc; <br>

int GetIfconf(); <br>

int send_arp (unsigned char*, unsigned char*, char*); <br>

  <br>

int main() <br>

{ <br>

    struct ifreq *ifr; <br>

    int sockfd, flags; <br>

    void *ptr; <br>

    char *pdev; <br>

    char dev[DEV_LEN], temp[16]; <br>

    unsigned char mac[ETH_HW_ADDR_LEN], ip[IP_ADDR_LEN]; <br>

  <br>

    if(GetIfconf() == -1) <br>

    //Warning: the result between kernel 2.0 and 2.2 is not the same!!! <br>

    //In kernel 2.0, it doesn't display the netcard name whose status <br>

    //is down. <br>

        return -1; <br>

    if((sockfd=socket(AF_INET, SOCK_DGRAM, 0)) == -1) { <br>



        free(ifc.ifc_buf); <br>

        ifc.ifc_req = NULL; <br>

        return -1; <br>

    } <br>

    for(ptr=ifc.ifc_buf; (caddr_t)ptr < ifc.ifc_buf+ifc.ifc_len; ){ <br>

        ifr=(struct ifreq *)ptr; <br>

            //for the next one in buffer <br>

        ptr += sizeof(ifr->ifr_name)+sizeof(struct sockaddr); <br>

        strncpy(dev, ifr->ifr_name, DEV_LEN-1); <br>

        if(strcmp(dev, "lo") == 0)  //loopback device <br>

            continue; <br>

        else if((pdev = strchr(dev, ':')) != NULL) <br>

            //virtual device <br>

            *pdev = 0; <br>

        //get the ip address <br>

        if(ioctl(sockfd, SIOCGIFADDR, ifr) == -1) { <br>

            free(ifc.ifc_buf); <br>

            ifc.ifc_req = NULL; <br>

            close(sockfd); <br>

            return -1; <br>

        } <br>

        memcpy(ip, (void *)&((struct sockaddr_in *)&ifr->ifr_addr)->sin_addr.s_a <br>



dd <br>

r, sizeof(ip)); <br>

        //get the hardware address <br>

        if(ioctl(sockfd, SIOCGIFHWADDR, ifr) == -1) { <br>

            free(ifc.ifc_buf); <br>

            ifc.ifc_req = NULL; <br>

            close(sockfd); <br>

            return -1; <br>

        } <br>

        memcpy(mac, ifr->ifr_hwaddr.sa_data, ETH_HW_ADDR_LEN); <br>

        printf("%s ", dev); <br>

        inet_ntop(AF_INET, ip, temp, sizeof(temp)); <br>

        printf("%s ", temp); <br>

        printf("%x:%x:%x:%x:%x:%x\n", *mac, *(mac+1), *(mac+2), *(mac+3), *(mac+ <br>

4) <br>

, *(mac+5)); <br>

        //send arp broadcast <br>

        if(send_arp(ip, mac, dev) == -1) { <br>

            printf("send arp broadcast fail in dev: %s\n", dev); <br>

        } else { <br>

            printf("send arp broadcast success in dev: %s\n", dev); <br>

        } <br>

        } <br>

    }  //end for of struct ifreq <br>

    free(ifc.ifc_buf); <br>

    ifc.ifc_req = NULL; <br>

    close(sockfd); <br>

    return 0; <br>

} <br>

  <br>

//get the value of struct ifconf ifc <br>

//global variable: struct ifconf ifc <br>

int GetIfconf() <br>

{ <br>

    int sockfd; <br>

    int len, lastlen; <br>

    void *buf; <br>

  <br>

    if((sockfd=socket(AF_INET, SOCK_DGRAM, 0)) == -1) <br>

        return -1; <br>

    lastlen=0; <br>

    len=10*sizeof(struct ifconf); <br>

    //size of struct ifconf: 8 <br>

    //size of struct ifreq: 32 <br>

    for(;;){ <br>

    for(;;){ <br>

        buf=malloc(len); <br>

        ifc.ifc_len=len; <br>

        ifc.ifc_buf=buf; <br>

        if(ioctl(sockfd, SIOCGIFCONF, &ifc) <0) { <br>

            free(buf); <br>

            return -1; <br>

        } <br>

        else{ <br>

            if(ifc.ifc_len == lastlen) <br>

                break;  //success, the only point to exit for() <br>

            lastlen=ifc.ifc_len; <br>

        } <br>

        len += 10*sizeof(struct ifconf); <br>

        free(buf); <br>

    } <br>

    return 0; <br>

} <br>

  <br>

//Arp reply to a broadcast MAC address, the target ip address is the same <br>

//with source address. :) <br>

int send_arp (unsigned char *sip, unsigned char *shwa, char *dev) <br>

{ <br>

{ <br>

    struct arp_packet pkt; <br>

    struct sockaddr sa; <br>

    int sock; <br>

    sock = socket(AF_INET, SOCK_PACKET, htons(ETH_P_ARP)); <br>

    if (sock < 0) { <br>

        printf("create socket error, this program need root privilege.\n"); <br>

        exit(1); <br>

    } <br>

  <br>

    memset(pkt.targ_hw_addr, 0xff, ETH_HW_ADDR_LEN); <br>

    memcpy(pkt.src_hw_addr, shwa, ETH_HW_ADDR_LEN); <br>

    pkt.frame_type     = htons(ETHERTYPE_ARP);  //0x0806 <br>

    pkt.hw_type        = htons(ARPHRD_ETHER);   //1 <br>

    pkt.prot_type      = htons(ETHERTYPE_IP);   //0x0800 <br>

    pkt.hw_addr_size   = ETH_HW_ADDR_LEN;       //6 <br>

    pkt.prot_addr_size = IP_ADDR_LEN;       //4 <br>

    pkt.op             = htons(ARPOP_REPLY);    //arp reply <br>

    memcpy(pkt.sndr_hw_addr, shwa, ETH_HW_ADDR_LEN); <br>

    memcpy(pkt.sndr_ip_addr, sip, IP_ADDR_LEN); <br>

    memcpy(pkt.rcpt_hw_addr, shwa, ETH_HW_ADDR_LEN); <br>

    memcpy(pkt.rcpt_ip_addr, sip, IP_ADDR_LEN); <br>

    bzero(pkt.padding,18); <br>



    strcpy(sa.sa_data,dev); <br>

  <br>

    if (sendto(sock,&pkt,sizeof(pkt),0,&sa,sizeof(sa)) < 0) { <br>

         printf("sendto error\n"); <br>

     close(sock); <br>

     return -1; <br>

    } <br>

    close(sock); <br>

    return 0; <br>

} <br>

  <br>

  <br>

The result the program: <br>

eth0 192.168.1.69 0:10:b2:4c:68:a <br>

send arp broadcast success in dev: eth0 <br>

//eth0:1 192.168.3.69 is a virtual netcard <br>

eth0 192.168.3.69 0:10:b2:4c:68:a <br>

send arp broadcast success in dev: eth0 <br>

eth1 192.168.2.69 0:d0:b7:e0:8f:e1 <br>

send arp broadcast success in dev: eth1 <br>

  <br>

  <br>



The packets captured through: #tcpdump -b arp <br>

15:42:07.789273 eth1 B arp reply 192.168.1.69 is-at 0:10:b2:4c:68:a (0:10:b2 <br>

:4c:68:a) <br>

15:42:07.789273 eth1 B arp reply 192.168.3.69 is-at 0:10:b2:4c:68:a (0:10:b2 <br>

:4c:68:a) <br>

15:42:07.789273 eth0 B arp reply 192.168.2.69 is-at 0:d0:b7:e0:8f:e1 (0:d0:b <br>

7:e0:8f:e1) <br>

  <br>

  <br>

-- <br>

易朽的是生命，似那转瞬即谢的花朵；然而永存的，是对未来的渴望， <br>

是那生生世世传递下来的，不朽的，生的激情。每一朵勇敢开放的花， <br>

都是一个死亡唇边的微笑。 <br>

※ 来源:·UNIX编程 www.tiaozhan.com/unixbbs/·[FROM: 202.114.1.61] <br>

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