如何以编程方式找到在Linux中为特定网络设备配置的IP地址/网络掩码/网关？

确保使用了ifreq和ioctl（）调用的结构，您可以获取所有接口信息：

手册页在这里Ifreq手册页

    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;         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，此功能要求在调用接口之前已经分配了接口，如下所示：

strcpy(if_cfg->iface, iface)

确保先分配了内存，然后像这样调用

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