Linux C语言 获取本机（所有网卡）IP地址（IPV4）

1、根据ioctl机制打印当前所有网卡

代码：

#include <sys/ioctl.h>
#include <net/if.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include <stdio.h>

int get_local_ip(char *ip)
{
int fd, intrface, retn = 0;
struct ifreq buf[INET_ADDRSTRLEN];
struct ifconf ifc;
if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) >= 0)
{
ifc.ifc_len = sizeof(buf);
// caddr_t,linux内核源码里定义的：typedef void *caddr_t；
ifc.ifc_buf = (caddr_t)buf;
if (!ioctl(fd, SIOCGIFCONF, (char *)&ifc))
{
intrface = ifc.ifc_len/sizeof(struct ifreq);
while (intrface-- > 0)
{
if (!(ioctl(fd, SIOCGIFADDR, (char *)&buf[intrface])))
{
ip=(inet_ntoa(((struct sockaddr_in*)(&buf[intrface].ifr_addr))->sin_addr));
printf("IP:%s\n", ip);
}
}
}
close(fd);
return 0;
}
}
int main()
{
char ip[64];
memset(ip, 0, sizeof(ip));
get_local_ip(ip);
return 0;
}

编译：

[root@localhost get_ip]# gcc -Wall -g ip.c

[root@localhost get_ip]# ./a.out

IP:192.168.2.53

IP:192.168.2.55

IP:127.0.0.1

代码解析：

<netinet/in.h>中定义了 #define INET_ADDRSTRLEN 16

ifreq、ifconf 、ioctl参考：/article/10924844.html

2、通过枚举网卡打印当前所有网卡

代码：

#include <stdio.h>
#include <ifaddrs.h>
#include <netinet/in.h>
#include <string.h>
#include <arpa/inet.h>

int get_local_ip(char *ip) {
struct ifaddrs *ifAddrStruct;
void *tmpAddrPtr=NULL;
getifaddrs(&ifAddrStruct);
while (ifAddrStruct != NULL) {
if (ifAddrStruct->ifa_addr->sa_family==AF_INET) {
tmpAddrPtr=&((struct sockaddr_in *)ifAddrStruct->ifa_addr)->sin_addr;
inet_ntop(AF_INET, tmpAddrPtr, ip, INET_ADDRSTRLEN);
printf("%s IP Address:%s\n", ifAddrStruct->ifa_name, ip);
}
ifAddrStruct=ifAddrStruct->ifa_next;
}
//free ifaddrs
freeifaddrs(ifAddrStruct);
return 0;
}

int main()
{
char ip[16];
memset(ip, 0, sizeof(ip));
get_local_ip(ip);
return 0;
}

编译：

[root@localhost get_ip]# gcc -Wall -g ip.c

[root@localhost get_ip]# ./a.out

lo IP Address:127.0.0.1

eth0 IP Address:192.168.2.55

eth1 IP Address:192.168.2.53

代码解析：

API接口可查看man 7 netdevice

3、多网卡情况下，将所有IP地址以字符串形式打印出，用逗号（“，”）隔开，形式如：“127.0.0.1,192.168.2.55,192.168.2.53”

代码：

#include <stdio.h>
#include <ifaddrs.h>
#include <netinet/in.h>
#include <string.h>
#include <arpa/inet.h>

int get_local_ip(char *ips) {
struct ifaddrs *ifAddrStruct;
void *tmpAddrPtr=NULL;
char ip[INET_ADDRSTRLEN];
int n = 0;
getifaddrs(&ifAddrStruct);
while (ifAddrStruct != NULL) {
if (ifAddrStruct->ifa_addr->sa_family==AF_INET) {
tmpAddrPtr=&((struct sockaddr_in *)ifAddrStruct->ifa_addr)->sin_addr;
inet_ntop(AF_INET, tmpAddrPtr, ip, INET_ADDRSTRLEN);
printf("%s IP Address:%s\n", ifAddrStruct->ifa_name, ip);
if (n == 0){
strncat(ips, ip, INET_ADDRSTRLEN);
} else {
strncat(ips, ",", 1);
strncat(ips, ip, INET_ADDRSTRLEN);
}
n++;
}
ifAddrStruct=ifAddrStruct->ifa_next;
}
//free ifaddrs
freeifaddrs(ifAddrStruct);
return 0;
}
int main()
{
char ip[64];
memset(ip, 0, sizeof(ip));
get_local_ip(ip);
printf("IP:%s\n", ip);
return 0;
}

编译：

[root@localhost get_ip]# gcc -Wall -g ip.c

[root@localhost get_ip]# ./a.out

lo IP Address:127.0.0.1

eth0 IP Address:192.168.2.55

eth1 IP Address:192.168.2.53

IP:127.0.0.1,192.168.2.55,192.168.2.53

4、多网卡情况下，将多个ip地址放入字符串数组中（去掉"127.0.0.1"地址）

代码：

#include <stdio.h>
#include <ifaddrs.h>
#include <netinet/in.h>
#include <string.h>
#include <arpa/inet.h>

int get_local_ip(char *ip_list) {
struct ifaddrs *ifAddrStruct;
void *tmpAddrPtr;
char ip[INET_ADDRSTRLEN];
int n = 0;
getifaddrs(&ifAddrStruct);
while (ifAddrStruct != NULL) {
if (ifAddrStruct->ifa_addr->sa_family==AF_INET) {
tmpAddrPtr=&((struct sockaddr_in *)ifAddrStruct->ifa_addr)->sin_addr;
inet_ntop(AF_INET, tmpAddrPtr, ip, INET_ADDRSTRLEN);
if (strcmp(ip, "127.0.0.1") != 0) {
//                              printf("%s IP Address:%s\n", ifAddrStruct->ifa_name, ip);
if (n == 0){
memcpy(ip_list, ip, INET_ADDRSTRLEN);
} else {
memcpy(ip_list+INET_ADDRSTRLEN, ip, INET_ADDRSTRLEN);
}
n++;
}
}
ifAddrStruct=ifAddrStruct->ifa_next;
}
//free ifaddrs
freeifaddrs(ifAddrStruct);
return n;
}
int main()
{
char ip[3][INET_ADDRSTRLEN];
memset(ip, 0, sizeof(ip));
int n;
for (n=get_local_ip(*ip); n>0; n--) {
printf("IP:%s\n", ip[n-1]);
}
return 0;
}

编译：

[root@localhost get_ip]# gcc -Wall -g ip.c

[root@localhost get_ip]# ./a.out

IP:192.168.2.53

IP:192.168.2.55