当然,使用 ifreq 和 ioctl() 调用的结构可以获取所有接口信息:
手册页在这里Ifreq 联机帮助页
/* 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,该函数需要在调用之前分配接口,如下所示:
strcpy(if_cfg->iface, iface)
确保您已经分配了内存,然后像这样调用
if((get_local_info(sock, if_cfg)) != 0){
printf("Unable to get network device info\n");
return -1;
}