我怎样才能找到编程的IP地址/掩码/配置在Linux中特定的网络设备网关？ [英] How can I programmatically find the IP address/netmask/gateway configured for a specific network device in Linux?

问题描述

嗨结果
我想编写一段code的它检查，每个网络设备（例如eth0的，不料，主设备）的一些统计数据和配置数据有关的设备。结果
我能找到的统计数据（以及大多数配置数据）的/ SYS /班/ NET / ...，但是，我无法找到的procfs / sysfs中列出INET地址的C / C ++ API或任何条目，子网掩码和网关。

Hi
I would like to write a piece of code which checks, for each network device (e.g. eth0, lo, master devices) some statistics and configuration data about that device.
I could find the statistics data (and most of the configuration data) in /sys/class/net/..., however, I couldn't find any C/C++ API or any entry in procfs/sysfs listing the inet addr, netmask and gateway.

一些替代我查了一下：

• 分析从使用ifconfig /路由/其他实用程序输出：我不想每次我需要做检查的时间启动子
。

• 解析在/ etc / sysconfig / network中的脚本/：会给我只启动配置，而不​​是目前的状态

此外，由于此code是用于在我的工作场所，其中的每个外部库彻底检查产品（这意味着它会带我永远添加任何外部库）I preFER解决方案，这依赖于Linux原生API，而不是外部库。

Also, since this code is intended for a product in my workplace, where every external library is inspected thoroughly (meaning it will take me forever to add any external library) I prefer solutions which rely on Linux native API and not external libraries.

谢谢！

推荐答案

有肯定是使用的ifreq和ioctl（的结构）调用，你可以抓住所有接口的信息：

There sure is using a struct of ifreq and ioctl() calls you can grab all interface information:

男人页面在这里<一个href=\"http://h30097.www3.hp.com/docs/dev_doc/DOCUMENTATION/HTML/DDK_R2/DOCS/HTML/MAN/MAN9/0143___S.HTM\">Ifreq手册页

/* local interface info */
    typedef struct{
        char *iface;
        struct ether_addr hwa;
        struct in_addr ipa;
        struct in_addr bcast;
        struct in_addr nmask;
        u_short mtu;
    } ifcfg_t; 
    /*
     * Grabs local network interface information and stores in a ifcfg_t 
     * defined in network.h, returns 0 on success -1 on failure
    */
    int get_local_info(int rsock, ifcfg_t *ifcfg)
    {
        struct ifreq ifr;

        memset(&ifr, 0, sizeof(ifr));
        strncpy(ifr.ifr_name, ifcfg->iface, IF_NAMESIZE);
        if((ioctl(rsock, SIOCGIFHWADDR, &ifr)) == -1){
            perror("ioctl():");
            return -1;
        }
        memcpy(&(ifcfg->hwa), &ifr.ifr_hwaddr.sa_data, 6);

        memset(&ifr, 0, sizeof(ifr));
        strncpy(ifr.ifr_name, ifcfg->iface, IF_NAMESIZE);
        if((ioctl(rsock, SIOCGIFADDR, &ifr)) == -1){
            perror("ioctl():");
            return -1;
        }
        memcpy(&ifcfg->ipa, &(*(struct sockaddr_in *)&ifr.ifr_addr).sin_addr, 4);

        memset(&ifr, 0, sizeof(ifr));
        strncpy(ifr.ifr_name, ifcfg->iface, IF_NAMESIZE);
        if((ioctl(rsock, SIOCGIFBRDADDR, &ifr)) == -1){
            perror("ioctl():");
            return -1;
        }
        memcpy(&ifcfg->bcast, &(*(struct sockaddr_in *)&ifr.ifr_broadaddr).sin_addr, 4);

        memset(&ifr, 0, sizeof(ifr));
        strncpy(ifr.ifr_name, ifcfg->iface, IF_NAMESIZE);
        if((ioctl(rsock, SIOCGIFNETMASK, &ifr)) == -1){
            perror("ioctl():");
            return -1;
        }
        memcpy(&ifcfg->nmask.s_addr, &(*(struct sockaddr_in *)&ifr.ifr_netmask).sin_addr, 4);

        memset(&ifr, 0, sizeof(ifr));
        strncpy(ifr.ifr_name, ifcfg->iface, IF_NAMESIZE);
        if((ioctl(rsock, SIOCGIFMTU, &ifr)) == -1){
            perror("ioctl():");
            return -1;
        }
        ifcfg->mtu = ifr.ifr_mtu;

        return 0;
    }

快速编辑，此功能要求的接口已被分配它被称为前，像这样：

Quick edit, this function requires that the interface has been assigned before it is called, like so:

strcpy(if_cfg->iface, iface)

确保你第一次分配的内存，然后调用像这样

Ensuring you have allocated the memory first, then call like so

if((get_local_info(sock, if_cfg)) != 0){
    printf("Unable to get network device info\n");
    return -1;
}

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