在Linux下开发网络程序时,经常会遇到需要取本地网络接口名、IP、广播地址、子网掩码或者MAC地址等信息的需求,最常见的办法是配合宏SIOCGIFHWADDR、SIOCGIFADDR、SIOCGIFBRDADDR与SIOCGIFNETMASK作为参数调用函数ioctl分别获得MAC地址、IP地址、广播地址与子网掩码来实现。一次性获取此类信息的C语言代码实现如下。
#include <stdio.h> #include <string.h> #include <net/if.h> #include <sys/ioctl.h> #include <arpa/inet.h> #include <errno.h> int getLocalInfo(void) { int fd; int interfaceNum = 0; struct ifreq buf[16]; struct ifconf ifc; struct ifreq ifrcopy; char mac[16] = {0}; char ip[32] = {0}; char broadAddr[32] = {0}; char subnetMask[32] = {0}; if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) { perror("socket"); close(fd); return -1; } ifc.ifc_len = sizeof(buf); ifc.ifc_buf = (caddr_t)buf; if (!ioctl(fd, SIOCGIFCONF, (char *)&ifc)) { interfaceNum = ifc.ifc_len / sizeof(struct ifreq); printf("interface num = %d\n", interfaceNum); while (interfaceNum-- > 0) { printf("\ndevice name: %s\n", buf[interfaceNum].ifr_name); //ignore the interface that not up or not runing ifrcopy = buf[interfaceNum]; if (ioctl(fd, SIOCGIFFLAGS, &ifrcopy)) { printf("ioctl: %s [%s:%d]\n", strerror(errno), __FILE__, __LINE__); close(fd); return -1; } //get the mac of this interface if (!ioctl(fd, SIOCGIFHWADDR, (char *)(&buf[interfaceNum]))) { memset(mac, 0, sizeof(mac)); snprintf(mac, sizeof(mac), "%02x%02x%02x%02x%02x%02x", (unsigned char)buf[interfaceNum].ifr_hwaddr.sa_data[0], (unsigned char)buf[interfaceNum].ifr_hwaddr.sa_data[1], (unsigned char)buf[interfaceNum].ifr_hwaddr.sa_data[2], (unsigned char)buf[interfaceNum].ifr_hwaddr.sa_data[3], (unsigned char)buf[interfaceNum].ifr_hwaddr.sa_data[4], (unsigned char)buf[interfaceNum].ifr_hwaddr.sa_data[5]); printf("device mac: %s\n", mac); } else { printf("ioctl: %s [%s:%d]\n", strerror(errno), __FILE__, __LINE__); close(fd); return -1; } //get the IP of this interface if (!ioctl(fd, SIOCGIFADDR, (char *)&buf[interfaceNum])) { snprintf(ip, sizeof(ip), "%s", (char *)inet_ntoa(((struct sockaddr_in *)&(buf[interfaceNum].ifr_addr))->sin_addr)); printf("device ip: %s\n", ip); } else { printf("ioctl: %s [%s:%d]\n", strerror(errno), __FILE__, __LINE__); close(fd); return -1; } //get the broad address of this interface if (!ioctl(fd, SIOCGIFBRDADDR, &buf[interfaceNum])) { snprintf(broadAddr, sizeof(broadAddr), "%s", (char *)inet_ntoa(((struct sockaddr_in *)&(buf[interfaceNum].ifr_broadaddr))->sin_addr)); printf("device broadAddr: %s\n", broadAddr); } else { printf("ioctl: %s [%s:%d]\n", strerror(errno), __FILE__, __LINE__); close(fd); return -1; } //get the subnet mask of this interface if (!ioctl(fd, SIOCGIFNETMASK, &buf[interfaceNum])) { snprintf(subnetMask, sizeof(subnetMask), "%s", (char *)inet_ntoa(((struct sockaddr_in *)&(buf[interfaceNum].ifr_netmask))->sin_addr)); printf("device subnetMask: %s\n", subnetMask); } else { printf("ioctl: %s [%s:%d]\n", strerror(errno), __FILE__, __LINE__); close(fd); return -1; } } } else { printf("ioctl: %s [%s:%d]\n", strerror(errno), __FILE__, __LINE__); close(fd); return -1; } close(fd); return 0; } int main(void) { getLocalInfo(); return 0; }
使用ioctl函数虽然可以获取所有的信息,但是使用起来比较麻烦,如果不需要获取MAC地址,那么使用getifaddrs函数来获取更加方便与简洁。值得一提的是,在MacOS或iOS系统上(如iPhone程序开发),上述iotcl函数没法获得mac地址跟子网掩码,这个使用,使用getifaddrs函数便更有优势了。下面是使用getiaddrs函数获取网卡信息的C语言代码实现。
#include <stdio.h> #include <ifaddrs.h> #include <arpa/inet.h> int getSubnetMask() { struct sockaddr_in *sin = NULL; struct ifaddrs *ifa = NULL, *ifList; if (getifaddrs(&ifList) < 0) return -1; for (ifa = ifList; ifa != NULL; ifa = ifa->ifa_next) { if(ifa->ifa_addr->sa_family == AF_INET) { printf("\n>>> interfaceName: %s\n", ifa->ifa_name); sin = (struct sockaddr_in *)ifa->ifa_addr; printf(">>> ipAddress: %s\n", inet_ntoa(sin->sin_addr)); sin = (struct sockaddr_in *)ifa->ifa_dstaddr; printf(">>> broadcast: %s\n", inet_ntoa(sin->sin_addr)); sin = (struct sockaddr_in *)ifa->ifa_netmask; printf(">>> subnetMask: %s\n", inet_ntoa(sin->sin_addr)); } } freeifaddrs(ifList); return 0; } int main(void) { getSubnetMask(); return 0; }
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真不错学习了 🙂 😆
3Q~
在suse下,如果要获取所有物理网卡的MAC应该如何实现?只要是这个机器上的网卡,都获取
第一种方法应该就可以实现呀~