Linux下获得本机ip

java版

private InetAddress getLocalIp() throws SocketException{
    Enumeration<NetworkInterface> e = NetworkInterface.getNetworkInterfaces();
    while(e.hasMoreElements()){
        NetworkInterface ni = e.nextElement();
        if("eth0".equals(ni.getName())){
            Enumeration<InetAddress> e2 = ni.getInetAddresses();
            while (e2.hasMoreElements()) {
                InetAddress ia = e2.nextElement();
                if (ia instanceof Inet4Address){
                    return ia;
                }
            }
        }
    }
    return null;
}

python版：

import socket
import fcntl
import struct
 
def get_ip_address(ifname):
    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    return socket.inet_ntoa(fcntl.ioctl(
        s.fileno(),
        0x8915,  # SIOCGIFADDR
        struct.pack('256s', ifname[:15])
    )[20:24])

print get_ip_address('eth0')

c版：

#include <stdio.h>  
#include <netdb.h>  
#include <arpa/inet.h>  
#include <sys/ioctl.h>  
#include <net/if.h>  

// 根据传入的网卡名，查询相应的ip，比如eth0,wlan0
char* get_ip(const char *inter_name){
    int s;
    struct ifconf conf;
    struct ifreq *ifr;
    char buff[BUFSIZ];
    int num, i;
    size_t l;

    s = socket(PF_INET, SOCK_DGRAM, 0); 
    conf.ifc_len = BUFSIZ;
    conf.ifc_buf = buff;

    ioctl(s, SIOCGIFCONF, &conf);
    num = conf.ifc_len / sizeof(struct ifreq);
    ifr = conf.ifc_req;

    for(i=0; i<num; i++){
        struct sockaddr_in *sin = (struct sockaddr_in *)(&ifr->ifr_addr);
        ioctl(s, SIOCGIFFLAGS, ifr);
        if( 
            ((ifr->ifr_flags & IFF_LOOPBACK) == 0)
                && (ifr->ifr_flags & IFF_UP)
        ){  
            if(strcmp(ifr->ifr_name, inter_name) == 0){ 
                return inet_ntoa(sin->sin_addr);
            }   
        }   
        ifr++;
    }   

    // 没有查询到相应的网卡的ip
    return NULL;
}


int main(int argc, char **argv){
    const char *s = get_ip(argv[1]);
    if(s != NULL)
        printf("%s\n", s);
    else
        printf("the interface doesn't exist\n");
}

lua版：

采用c模块实现，使用上面c版的代码。

#include <stdio.h>  
#include <netdb.h>  
#include <arpa/inet.h>  
#include <sys/ioctl.h>  
#include <net/if.h>  
#include <lua.h>
#include <lauxlib.h>
#include <lualib.h>
  
static int get_ip(lua_State *L){
	int s;
	struct ifconf conf;
	struct ifreq *ifr;
	char buff[BUFSIZ];
	int num, i;
	size_t l;
	const char *inter_name;

	s = socket(PF_INET, SOCK_DGRAM, 0);
	conf.ifc_len = BUFSIZ;
	conf.ifc_buf = buff;

	ioctl(s, SIOCGIFCONF, &conf);
	num = conf.ifc_len / sizeof(struct ifreq);
	ifr = conf.ifc_req;

	inter_name = lua_tolstring(L, -1, &l);
	for(i=0; i<num; i++){
		struct sockaddr_in *sin = (struct sockaddr_in *)(&ifr->ifr_addr);
		ioctl(s, SIOCGIFFLAGS, ifr);
		if(
			((ifr->ifr_flags & IFF_LOOPBACK) == 0)
				&& (ifr->ifr_flags & IFF_UP)
		){
			if(strcmp(ifr->ifr_name, inter_name) == 0){
				lua_pushstring(L, inet_ntoa(sin->sin_addr));	
				return 1;
			} 
		}
		ifr++;
	}

	// 没有查询到相应的网卡的ip
	lua_pushstring(L, "null");
	return 1;
}

static const struct luaL_Reg iplib[] = {
	{"get_ip", get_ip},
	{NULL, NULL}
};

int luaopen_iplib(lua_State *L){
	luaL_register(L, "iplib", iplib);
	return 1;
}

        然后编译成动态链接库：

gcc -fpic -shared -I <path-to-lua-include> -o iplib.so iplib.c 

        指定iplib.so在LUA_CPATH下，在lua中可以这样使用：

local ip = require('iplib')

ip_addr = ip.get_ip('eth0')
print(ip_addr)