获取网络接口索引 [英] Get index of network interface

问题描述

我正在为C上的OS X编写简单的嗅探器 所以，我有一个问题，我无法获取网络接口的索引. 我使用以下代码:

I'm writing simple sniffer for OS X on C So, I have a problem, I can't get index of network interface. I use this code:

int sockfd=socket(PF_INET, SOCK_DGRAM, 0);
  if(sockfd<0)
  {
    printf("create socket");
    fprintf(stderr, "%s\n",strerror(errno));
    exit(EXIT_FAILURE);
  }
  sprintf( ifreq.ifr_name, "%s", "en0");
  if(ioctl(sockfd, SIOCGIFINDEX, &ifreq)<0) 
  {
    fprintf(stderr, "%s\n",strerror(errno));
    exit(EXIT_FAILURE);
  }

问题是未声明标识符"SIOCGIFINDEX". 如果我理解正确，则网络接口索引需要结构化sockaddr_ll

Problem that identifier 'SIOCGIFINDEX' is undeclared. Index of network interface need for structute sockaddr_ll , if I understand rightly

推荐答案

您也可以尝试看一下这段代码. 这将获得具有名称的界面，并对其进行处理. ifap 完成后，别忘了包含标题并释放内存.

You could also try and look at this code. This will get the interface with the name and do something with it. Don't forget to include the header and free the memory when you're done with ifap.

#include <ifaddrs.h>
void do_smth_with_interface(const char *name) 
{

    struct ifaddrs *ifap = NULL;

    if(getifaddrs(&ifap) < 0) {
        printf("Cannot get a list of interfaces\n");
        return;
    }

    for(struct ifaddrs *p = ifap; p!=NULL; p=p->ifa_next) {
        if (strcmp(p->ifa_name, name) == 0)
                // do smth with the interface.
    }

    freeifaddrs(ifap);
 }

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