linux 下获取所有网卡mac，name

linux下，   所有的网卡信息写在/proc/net/dev文件，这是个内存映射文件，我们可以从这个文件里面读出网卡名字，然后根据名字利用ioctl函数读出网卡别的信息，比如ip地址，网关，掩码之类的信息。

下面是可运行的代码：

#include

 #include
 #include
 #include
 #include
 #include
 #include
 int get_hwaddr(char *name);
 int GetNetCardCount()
 {
     int nCount = 0;
     FILE* f = fopen("/proc/net/dev", "r");
     if (!f)
     {
         fprintf(stderr, "Open /proc/net/dev failed!errno:%d\n", errno);
         return nCount;
     }
 
     char szLine[512];
 
     fgets(szLine, sizeof(szLine), f);    /* eat line */
     fgets(szLine, sizeof(szLine), f);
 
     while(fgets(szLine, sizeof(szLine), f))
     {
         char szName[128] = {0};
         sscanf(szLine, "%s", szName);
                 printf("szline %s\n", szName);
         int nLen = strlen(szName);
         if (nLen <= 0)continue;
         if (szName[nLen - 1] == ':') szName[nLen - 1] = 0;
         if (strcmp(szName, "lo") == 0)continue;
         nCount++;
         get_hwaddr(szName);
     }
 
     fclose(f);
     f = NULL;
     return nCount;
 }
    /**
     * get_hwaddr - get netdevice mac addr  
     * @name: device name, e.g: eth0
     * @hwaddr: where to save mac, 6 byte hwaddr[6]
     * @return: 0 on success, -1 on failure
     */  
    int get_hwaddr(char *name)//, unsigned char *hwaddr)  
    {  
        struct ifreq ifr;  
        unsigned char memzero[6];
        unsigned char hwaddr[6];
        int sock;  
      
        if(name == NULL || hwaddr == NULL){  
            printf("get_hwaddr: NULL para\n");  
            return -1;  
        }  
      
     sock = socket(AF_INET, SOCK_STREAM, 0);  
        if(sock < 0){  
            printf("get_hwaddr: socket error\n");  
            //return -1;  
        }  
      
        //get eth1 mac addr  
        memset(hwaddr, 0, 6);  
        memset(&ifr, 0, sizeof(ifr));  
        strncpy(ifr.ifr_name, name, 6);  
        if (ioctl(sock, SIOCGIFHWADDR, &ifr) < 0){  
                perror("get_hwaddr ioctl:");  
                close(sock);  
                return -1;  
        } else {
                memcpy(hwaddr, ifr.ifr_hwaddr.sa_data, 6);  
                printf("hwaddr: %2x : %2x : %2x : %2x : %2x : %2x\n", hwaddr[0], hwaddr[1],hwaddr[2], hwaddr[3],hwaddr[4], hwaddr[5]);  
        }

        memset(memzero, 0, 6);  
        if(memcmp(memzero, hwaddr, 6) == 0){  
            printf("no mac\n");  
            return -1;  
        }  
      
        close(sock);  
        return 0;  
    }
 int main(int argc, char* argv[])
 {
     printf("NetCardCount: %d\n", GetNetCardCount());
     return 0;
 }