获取本地 ip 地址，mac，通过域名获取对应的 ip，
是网络编程可能遇到的比较常见的操作了，所以总结如下（封装了3个函数）
代码#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <netdb.h>
#include <net/if.h>
#include <arpa/inet.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/socket.h>
#define MAC_SIZE 18
#define IP_SIZE 16
// function declare
int get_ip_by_domain(const char *domain, char *ip); // 根据域名获取ip
int get_local_mac(const char *eth_inf, char *mac); // 获取本机mac
int get_local_ip(const char *eth_inf, char *ip); // 获取本机ip
/****** main test **********/
int main(void)
{
char ip[IP_SIZE];
char mac[MAC_SIZE];
const char *test_domain = "www.baidu.com";
const char *test_eth = "eth0";
get_ip_by_domain(test_domain, ip);
printf("%s ip: %s\n", test_domain, ip);
get_local_mac(test_eth, mac);
printf("local %s mac: %s\n", test_eth, mac);
get_local_ip(test_eth, ip);
printf("local %s ip: %s\n", test_eth, ip);
return 0;
}
// 根据域名获取ip
int get_ip_by_domain(const char *domain, char *ip)
{
char **pptr;
struct hostent *hptr;
hptr = gethostbyname(domain);
if(NULL == hptr)
{
printf("gethostbyname error for host:%s/n", domain);
return -1;
}
for(pptr = hptr->h_addr_list ; *pptr != NULL; pptr++)
{
if (NULL != inet_ntop(hptr->h_addrtype, *pptr, ip, IP_SIZE) )
{
return 0; // 只获取第一个 ip
}
}
return -1;
}
// 获取本机mac
int get_local_mac(const char *eth_inf, char *mac)
{
struct ifreq ifr;
int sd;
bzero(&ifr, sizeof(struct ifreq));
if( (sd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
{
printf("get %s mac address socket creat error\n", eth_inf);
return -1;
}
strncpy(ifr.ifr_name, eth_inf, sizeof(ifr.ifr_name) - 1);
if(ioctl(sd, SIOCGIFHWADDR, &ifr) < 0)
{
printf("get %s mac address error\n", eth_inf);
close(sd);
return -1;
}
snprintf(mac, MAC_SIZE, "%02x:%02x:%02x:%02x:%02x:%02x",
(unsigned char)ifr.ifr_hwaddr.sa_data[0],
(unsigned char)ifr.ifr_hwaddr.sa_data[1],
(unsigned char)ifr.ifr_hwaddr.sa_data[2],
(unsigned char)ifr.ifr_hwaddr.sa_data[3],
(unsigned char)ifr.ifr_hwaddr.sa_data[4],
(unsigned char)ifr.ifr_hwaddr.sa_data[5]);
close(sd);
return 0;
}
// 获取本机ip
int get_local_ip(const char *eth_inf, char *ip)
{
int sd;
struct sockaddr_in sin;
struct ifreq ifr;
sd = socket(AF_INET, SOCK_DGRAM, 0);
if (-1 == sd)
{
printf("socket error: %s\n", strerror(errno));
return -1;
}
strncpy(ifr.ifr_name, eth_inf, IFNAMSIZ);
ifr.ifr_name[IFNAMSIZ - 1] = 0;
// if error: No such device
if (ioctl(sd, SIOCGIFADDR, &ifr) < 0)
{
printf("ioctl error: %s\n", strerror(errno));
close(sd);
return -1;
}
memcpy(&sin, &ifr.ifr_addr, sizeof(sin));
snprintf(ip, IP_SIZE, "%s", inet_ntoa(sin.sin_addr));
close(sd);
return 0;
}
运行结果
