linux 判断网线是否插入

你的名字 2021-08-28 19:23 541阅读 0赞

1.检查网线是否插入可以查看  
  
/sys/class/net/eth0/carrier 文件的内容。 1 表示网线有插入， 0 表示没接网线。

2.Netlink实现网卡上下线监控：

#include <sys/types.h>  
    #include <sys/socket.h>  
    #include <asm/types.h>  
    #include <linux/netlink.h>  
    #include <linux/rtnetlink.h>  
    #include <unistd.h>
    #include <stdlib.h>  
    #include <stdio.h>  
    #include <sys/ioctl.h>  
    #include <linux/if.h>  
    #include <string.h>  
      
    #define BUFLEN 20480  
      
    int main(int argc, char *argv[])  
    {  
        int fd, retval;  
        char buf[BUFLEN] = {0};  
        int len = BUFLEN;  
        struct sockaddr_nl addr;  
        struct nlmsghdr *nh;  
        struct ifinfomsg *ifinfo;  
        struct rtattr *attr;  
      
        fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);  
        setsockopt(fd, SOL_SOCKET, SO_RCVBUF, &len, sizeof(len));  
        memset(&addr, 0, sizeof(addr));  
        addr.nl_family = AF_NETLINK;  
        addr.nl_groups = RTNLGRP_LINK;  
        bind(fd, (struct sockaddr*)&addr, sizeof(addr));  
        while ((retval = read(fd, buf, BUFLEN)) > 0)  
        {  
            for (nh = (struct nlmsghdr *)buf; NLMSG_OK(nh, retval); nh = NLMSG_NEXT(nh, retval))  
            {  
                if (nh->nlmsg_type == NLMSG_DONE)  
                    break;  
                else if (nh->nlmsg_type == NLMSG_ERROR)  
                    return -1;  
                else if (nh->nlmsg_type != RTM_NEWLINK)  
                    continue;  
                ifinfo = NLMSG_DATA(nh);  
                printf("%u: %s", ifinfo->ifi_index,  
                        (ifinfo->ifi_flags & IFF_LOWER_UP) ? "up" : "down" );  
                attr = (struct rtattr*)(((char*)nh) + NLMSG_SPACE(sizeof(*ifinfo)));  
                len = nh->nlmsg_len - NLMSG_SPACE(sizeof(*ifinfo));  
                for (; RTA_OK(attr, len); attr = RTA_NEXT(attr, len))  
                {  
                    if (attr->rta_type == IFLA_IFNAME)  
                    {  
                        printf(" %s", (char*)RTA_DATA(attr));  
                        break;  
                    }  
                }  
                printf("\n");  
            }  
        }  
      
        return 0;  
    }