c-使用setsockopt()系统绑定设备的原始套接字在Fedora core 6(2.6.18-1.2798.fc6

Question

请任何人在这个问题上提供帮助。请

在下面的示例代码中，我们用eth0绑定了生袜子。但是在运行程序时原始sock的recvfrom正在接收来自eth0&eth1在同一台机器上（xx_86）。我不清楚为什么，可以在这个问题上帮助一个人。我希望setsockopt不能正常工作操作系统：Fedora核心6（2.6.18-1.2798.fc6）

样本代码：

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <linux/if_ether.h>
#include <net/if.h>
#include <linux/filter.h>
#include <sys/ioctl.h> 
#include <string.h>
#include <arpa/inet.h>
int main(int argc, char **argv) {
int sock, i;
unsigned char buffer[2048];
unsigned char tbuff[2048];
unsigned char *iphead, *ethhead,*phead;
struct ifreq ethreq;
// NOTE: use TCPDUMP to build the filter array.
// set filter to sniff only port 443
// $ sudo tcpdump -dd port 443
// raw for recvfrom eth0
if ((sock = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_IP))) == -1) {
    perror("socket");
    exit(1);
}
  // set network card to promiscuos
strncpy(ethreq.ifr_name, "eth0", IFNAMSIZ);
if (ioctl(sock,SIOCGIFFLAGS, &ethreq) == -1) {
    perror("ioctl");
    close(sock);
    exit(1);
}
ethreq.ifr_flags |= IFF_PROMISC;
if (ioctl(sock, SIOCSIFFLAGS, &ethreq) == -1) {
    perror("ioctl");
    close(sock);
    exit(1);
}
//bind to sock with eth0 
 struct ifreq Interface;
 memset(&Interface, 0, sizeof(Interface));
 strncpy(Interface.ifr_ifrn.ifrn_name, "eth0", IFNAMSIZ);
 if (setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, &Interface, sizeof(Interface)) < 0)    { close(sock); }

    //open the RAW socket for sendto
 int s = socket (PF_INET, SOCK_RAW, IPPROTO_RAW);
     struct sockaddr_in sin;
     memset(&sin,0,sizeof(sin));
     sin.sin_family = AF_INET;
     sin.sin_port = htons(0);
     sin.sin_addr.s_addr = inet_addr ("10.3.161.104");
  // inform kernal don't fill IP and Transport header
     int one = 1;
     const int *val = &one;
     if (setsockopt (s, IPPROTO_IP, IP_HDRINCL, val, sizeof (one)) < 0)
     printf ("Warning: Cannot set HDRINCL!n");
     //bind the sock descriptor with eth0
     struct ifreq Interface1;
     memset(&Interface1, 0, sizeof(Interface1));
     strncpy(Interface1.ifr_ifrn.ifrn_name, "eth0", IFNAMSIZ);
     if (setsockopt(s, SOL_SOCKET, SO_BINDTODEVICE, &Interface1, sizeof(Interface1)) < 0) { close(s); }

while (1) {
    printf("----------------------n");
    i = recvfrom(sock, buffer, sizeof(buffer), 0, NULL, NULL);
    printf("%d bytes readn", i);
    // check header size: Ethernet = 14, IP = 20, TCP = 8 (sum = 42)
    if (i < 42) {
        perror("recvfrom():");
        printf("Incomplete packet (errno is %d)n", errno);
        close(sock);
        exit(0);
    }
    phead = buffer + 14; // (skip ethernet  header)
    memcpy(tbuff,phead,i-14); 
    iphead=tbuff;
    if (*iphead == 0x45) {
        int ptrindex= iphead[9];
        switch(ptrindex){
         case 1:
                printf("The transport protocl is:ICMPn");
                break;
         case 2:
                printf("The transport protol is:IGMPn");
                break;
         case 6:
               printf("The transport protocol is:TCPn");
               break;
         case 17:
               printf("The transport protocol is:UDPn");
               break;
         case 103:
              printf("The transport protocol is:PIMn"); 
              break; 
         default:
             printf("The transport protocol is:%dn",iphead[9]);
        }           
        //printf("%d",*ptrindex);
       // printf("n The transport protocol is :%un",iphead[9]);
        printf("Source Address: %d.%d.%d.%d, Port: %dn",
            iphead[12], iphead[13], iphead[14], iphead[15], (iphead[20] << 8) + iphead[21]);
        printf("Dest Address: %d.%d.%d.%d, Port: %dn",
            iphead[16], iphead[17], iphead[18], iphead[19], (iphead[22] << 8) + iphead[23]);

     if(sendto(s,tbuff,i-14,0,(struct sockaddr *)&sin,sizeof(sin))<0)
      printf("errorn");
     else{printf("nThe received packet is sendn");}
     memset(buffer,0,sizeof(buffer));
     memset(tbuff,0,sizeof(tbuff));
    }
   else{ printf("The non ip had received");}
    }
       close(sock);
}

Answer 1

在linux手册页中(http://linux.die.net/man/7/socket)：

SO_结合力

根据传递的接口名称中的指定，将此套接字绑定到一个特定的设备，如"eth0"。如果名称是空字符串或选项长度为零，则套接字设备绑定将被删除。传递的选项是一个可变长度的以null结尾的接口名称字符串，最大大小为IFNAMSIZ。如果套接字绑定到某个接口，则套接字只处理从该特定接口接收的数据包。请注意，这只适用于某些套接字类型，特别是AF_INET套接字数据包套接字不支持它（在那里使用普通绑定（2））。

因此，请尝试绑定。

Answer 2

谢谢大家，非常感谢您抽出宝贵的时间。它采用绑定方法代码段帮助了我。

setsockopt()是fedora 2.6.18 中的错误

替代方法如下。

void BindToInterface(int raw , char *device , int protocol) { 
    struct sockaddr_ll sll;
    struct ifreq ifr; bzero(&sll , sizeof(sll));
    bzero(&ifr , sizeof(ifr)); 
    strncpy((char *)ifr.ifr_name ,device , IFNAMSIZ); 
    //copy device name to ifr 
    if((ioctl(raw , SIOCGIFINDEX , &ifr)) == -1)
    { 
        perror("Unable to find interface index");
        exit(-1); 
    }
    sll.sll_family = AF_PACKET; 
    sll.sll_ifindex = ifr.ifr_ifindex; 
    sll.sll_protocol = htons(protocol); 
    if((bind(raw , (struct sockaddr *)&sll , sizeof(sll))) ==-1)
    {
        perror("bind: ");
        exit(-1);
    }
    return 0;
}