设置网卡混杂模式

17059阅读　0评论2012-11-22　lubing521
分类：网络与安全

      有时候为嗅探到网络上的数据，需要将网卡设置到混杂模式。进入该模式将网络上的数据一并抓获，为此在设置nic的混杂模式的时候有诸多方法？通过shell命令来实现：
ifconfig eth1 promisc  设置混杂模式
ifconfig eth1 -promisc 取消混杂模式
执行结果如下
[root@localhost tftpboot]# ifconfig
eth6      Link encap:Ethernet  HWaddr 08:00:27:70:1D:79  
          inet6 addr: fe80::a00:27ff:fe70:1d79/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:100124 errors:0 dropped:0 overruns:0 frame:0
          TX packets:8795 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:12986638 (12.3 MiB)  TX bytes:6452270 (6.1 MiB)

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:1303 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1303 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:303973 (296.8 KiB)  TX bytes:303973 (296.8 KiB)

[root@localhost tftpboot]# ifconfig eth6 promisc
[root@localhost tftpboot]# ifconfig
eth6      Link encap:Ethernet  HWaddr 08:00:27:70:1D:79  
          inet6 addr: fe80::a00:27ff:fe70:1d79/64 Scope:Link
          UP BROADCAST RUNNING PROMISC MULTICAST  MTU:1500  Metric:1
          RX packets:100154 errors:0 dropped:0 overruns:0 frame:0
          TX packets:8795 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:13007885 (12.4 MiB)  TX bytes:6452270 (6.1 MiB)

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:1303 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1303 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:303973 (296.8 KiB)  TX bytes:303973 (296.8 KiB)

[root@localhost tftpboot]# 

也可以通过C语言方式编程来实现，

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  1. #include <stdio.h>
  2. #include <unistd.h>
  3. #include <sys/socket.h>
  4. #include <netinet/in.h>
  5. #include <arpa/inet.h>
  6. #include <errno.h>
  7. #include <linux/if_ether.h>
  8. #include <net/if.h>
  9. #include <sys/ioctl.h>
  10. #include <string.h>

  12. #define ETH_NAME    "eth1"

  14. int do_promisc(void) {
  15.     int f, s;
  16.     struct ifreq ifr;
  17.     if ( (f=socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL)))<0){
  18.         return -1;
  19.     }
  20.     strcpy(ifr.ifr_name, ETH_NAME);
  21.     
  22.     if ((s = ioctl(f, SIOCGIFFLAGS, &ifr))<0){
  23.       close(f);
  24.       return-1;
  25.     }
  26.     
  27.     if(ifr.ifr_flags & IFF_RUNNING){
  28.         printf("eth link up\n");
  29.     }else{
  30.         printf("eth link down\n");
  31.     }
  32.   
  33.     ifr.ifr_flags |= IFF_PROMISC;
  34.     if ((s = ioctl(f, SIOCSIFFLAGS, &ifr)) < 0){
  35.       return -1;
  36.     }
  37.     printf("Setting interface ::: %s ::: to promisc\n\n", ifr.ifr_name);
  38.     return 0;
  39. }

  41. int check_nic(void)
  42. {
  43.     struct ifreq ifr;
  44.     int skfd = socket(AF_INET, SOCK_DGRAM, 0);

  46.     strcpy(ifr.ifr_name, ETH_NAME);
  47.     if (ioctl(skfd, SIOCGIFFLAGS, &ifr) < 0)
  48.     {
  49.         close(skfd);
  50.         return -1;
  51.     }
  52.     if(ifr.ifr_flags & IFF_RUNNING){
  53.         printf("link up\n");
  54.         close(skfd);
  55.         return 0; // 网卡已插上网线
  56.     }else {
  57.         printf("link down\n");
  58.         close(skfd);
  59.         return -1;
  60.     }
  61. }



  65. int main(void) {
  66.     do_promisc();
  67.     return 0;
  68. }

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