UDP实现简单的ifconfig查询功能

谁借莪１个温暖的怀抱￠ 2021-09-19 01:04 282阅读 0赞

**一 代码**

#include <net/if.h> /* for ifconf */ 
 #include <linux/sockios.h> /* for net status mask */ 
 #include <netinet/in.h> /* for sockaddr_in */ 
 #include <sys/socket.h> 
 #include <sys/types.h> 
 #include <sys/ioctl.h> 
 #include <stdio.h> 
 #include <unistd.h> //for close
 #include <arpa/inet.h>
 #include <string.h>
 #define MAX_INTERFACE (16) 
 
 void port_status(unsigned int flags); 
 
 
 int get_if_info(int fd) 
 { 
 struct ifreq buf[MAX_INTERFACE]; 
 struct ifconf ifc; 
 int ret = 0; 
 int if_num = 0; 
 
 ifc.ifc_len = sizeof(buf); 
 ifc.ifc_buf = (caddr_t) buf; 
 
 ret = ioctl(fd, SIOCGIFCONF, (char*)&ifc); 
 if (ret) 
 { 
 printf("get if config info failed"); 
 return -1; 
 } 
 /* 网口总数 ifc.ifc_len 应该是一个出入参数 */ 
 if_num = ifc.ifc_len / sizeof(struct ifreq); 
 printf("interface num is interface = %d\n", if_num); 
 while (if_num-- > 0) 
 { 
 printf("net device: %s\n", buf[if_num].ifr_name); 
 /* 获取第n个网口信息 */ 
 ret = ioctl(fd, SIOCGIFFLAGS, (char*)&buf[if_num]); 
 if (ret) 
 continue; 
 
 /* 获取网口状态 */ 
 port_status(buf[if_num].ifr_flags); 
 
 /* 获取当前网卡的ip地址 */ 
 ret = ioctl(fd, SIOCGIFADDR, (char*)&buf[if_num]); 
 if (ret) 
 continue; 
 printf("IP address is: \n%s\n", inet_ntoa(((struct sockaddr_in *)(&buf[if_num].ifr_addr))->sin_addr)); 
 
 /* 获取当前网卡的mac */ 
 ret = ioctl(fd, SIOCGIFHWADDR, (char*)&buf[if_num]); 
 if (ret) 
 continue; 
 
 printf("%02x:%02x:%02x:%02x:%02x:%02x\n\n", 
 (unsigned char)buf[if_num].ifr_hwaddr.sa_data[0], 
 (unsigned char)buf[if_num].ifr_hwaddr.sa_data[1], 
 (unsigned char)buf[if_num].ifr_hwaddr.sa_data[2], 
 (unsigned char)buf[if_num].ifr_hwaddr.sa_data[3], 
 (unsigned char)buf[if_num].ifr_hwaddr.sa_data[4], 
 (unsigned char)buf[if_num].ifr_hwaddr.sa_data[5]); 
 } 
 } 
 
 void port_status(unsigned int flags) 
 { 
 if (flags & IFF_UP) 
 { 
 printf("is up\n"); 
 } 
 if (flags & IFF_BROADCAST) 
 { 
 printf("is broadcast\n"); 
 } 
 if (flags & IFF_LOOPBACK) 
 { 
 printf("is loop back\n"); 
 } 
 if (flags & IFF_POINTOPOINT) 
 { 
 printf("is point to point\n"); 
 } 
 if (flags & IFF_RUNNING) 
 { 
 printf("is running\n"); 
 } 
 if (flags & IFF_PROMISC) 
 { 
 printf("is promisc\n"); 
 } 
 } 
 
 int main() 
 { 
 int fd; 
 
 fd = socket(AF_INET, SOCK_DGRAM, 0); 
 if (fd > 0) 
 { 
 get_if_info(fd); 
 close(fd); 
 } 
 
 return 0; 
 }

**二 运行**

[root@localhost test]# g++ test.cpp -o test
    [root@localhost test]# ./test
    interface num is interface = 2
    net device: enp0s3
    is up
    is broadcast
    is running
    IP address is:
    192.168.0.120
    08:00:27:0c:3b:d3
    
    net device: lo
    is up
    is loop back
    is running
    IP address is:
    127.0.0.1
    00:00:00:00:00:00

**三 说明**

1 网络相关的ioctl请求的request参数及arg地址必须指向的数据类型如下表所示：

<table style="width:600px;"> 
 <tbody> 
 <tr> 
 <td> 接口 </td> 
 <td> SIOCGIFCONF SIOCSIFADDR SIOCGIFADDR SIOCSIFBRDADDR SIOCGIFBRDADDR SIOCSIFNETMASK SIOCGIFNETMASK </td> 
 <td> 获取所有接口列表 设置接口地址 获取接口地址 设置广播地址 获取广播地址 设置子网掩码 获取子网掩码 </td> 
 <td> Struct &nbsp;ifconf Struct &nbsp;ifreq Struct &nbsp;ifreq Struct &nbsp;ifreq Struct &nbsp;ifreq Struct &nbsp;ifreq Struct &nbsp;ifreq </td> 
 </tr> 
 </tbody> 
</table>

2  ifconf定义如下：

struct ifconf{
    lint ifc_len;
    union{
        caddr_t  ifcu_buf
        Struct   ifreq *ifcu_req;
    }ifc_ifcu
    }
    #define    ifc_buf    ifc_ifcu.ifcu_buf
    #define    ifc_req    ifc_ifcu.ifcu_req

3 本机所有的网卡信息都列举出来了，效果和ifconfig命令类似。