Linux 获得机器的IP和网卡信息代码来自于网络，我改写了，有美不敢自专，特分享之。用法很简单，就3个函数。
头文件getmac.h:
/**
* getmac.h
*
* 2014-07-08: init created
*/
#ifndef GETMAC_H_INCLUDED
#define GETMAC_H_INCLUDED
#if defined(__cplusplus)
extern "C" {
#endif
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/param.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <net/if.h>
#include <netinet/in.h>
#include <net/if_arp.h>
#include <arpa/inet.h>
#include <unistd.h>
#ifdef SOLARIS
# include <sys/sockio.h>
#endif
#define GETMAC_MAX_INTERFACES 16
#define GETMAC_MAX_MSGLEN 256
#define GETMAC_NOERROR 0
#define GETMAC_SUCCESS GETMAC_NOERROR
#define GETMAC_ERROR (-1)
#define GETMAC_EATTR (-2)
typedef int GETMAC_BOOL;
#define GETMAC_TRUE 1
#define GETMAC_FALSE 0
typedef struct
{
int fd;
struct ifreq buf[GETMAC_MAX_INTERFACES];
struct arpreq arp;
int ifaces;
} getmac_info_t;
typedef struct
{
int errcode;
char errmsg[GETMAC_MAX_MSGLEN];
} getmac_error_t;
#define GETMAC_ATTR_IFF_UP 1 /* Interface is up */
#define GETMAC_ATTR_IFF_BROADCAST 2 /* Broadcast address valid */
#define GETMAC_ATTR_IFF_DEBUG 3 /* Turn on debugging */
#define GETMAC_ATTR_IFF_LOOPBACK 4 /* Is a loopback net */
#define GETMAC_ATTR_IFF_POINTOPOINT 5 /* Interface is point-to-point link */
#define GETMAC_ATTR_IFF_NOTRAILERS 6 /* Avoid use of trailers */
#define GETMAC_ATTR_IFF_RUNNING 7 /* Resources allocated */
#define GETMAC_ATTR_IFF_NOARP 8 /* No address resolution protocol */
#define GETMAC_ATTR_IFF_PROMISC 9 /* Receive all packets */
#define GETMAC_ATTR_IFNAME 10 /* Interface name, e.g. "en0". */
#define GETMAC_ATTR_IPADDR 11 /* Address of interface */
#define GETMAC_ATTR_HWADDR 12 /* MAC address */
extern int getmac_init (getmac_info_t * mi, getmac_error_t * err);
extern int getmac_attr (getmac_info_t * mi, int i, int attr, void * value, getmac_error_t * err);
extern void getmac_fini (getmac_info_t * mi);
#if defined(__cplusplus)
}
#endif
#endif /* GETMAC_H_INCLUDED */
C文件getmac.c:
/**
* getmac.c
*
* 2014-07-08: init created
*/
#include "getmac.h"
int getmac_init (getmac_info_t * mi, getmac_error_t * err)
{
int fd;
struct ifconf ifc;
bzero (mi, sizeof(getmac_info_t));
mi->fd = -1;
fd = socket (AF_INET, SOCK_DGRAM, 0);
if (fd == -1) {
err->errcode = errno;
snprintf (err->errmsg, GETMAC_MAX_MSGLEN, "socket() error (%d): %s", strerror(errno));
return GETMAC_ERROR;
}
/* prepare to get mac numb */
ifc.ifc_len = sizeof(mi->buf);
ifc.ifc_buf = (caddr_t) mi->buf;
if (ioctl (fd, SIOCGIFCONF, (char *) &ifc)) {
err->errcode = errno;
snprintf (err->errmsg, GETMAC_MAX_MSGLEN, "ioctl() error (%d): %s", strerror(errno));
close (fd);
return GETMAC_ERROR;
}
mi->ifaces = ifc.ifc_len / sizeof (struct ifreq);
mi->fd = fd;
/* return numb of mac */
return mi->ifaces;
}
int getmac_attr (getmac_info_t * mi, int i, int attr, void * value, getmac_error_t * err)
{
if (mi->fd == -1) {
snprintf (err->errmsg, GETMAC_MAX_MSGLEN, "getmac_init should be invoked first");
return GETMAC_ERROR;
}
/* initialize if not a valid name */
if (! mi->buf[i].ifr_name[0]) {
if (ioctl (mi->fd, SIOCGIFFLAGS, (char *) & mi->buf[i])) {
err->errcode = errno;
snprintf (err->errmsg, GETMAC_MAX_MSGLEN, "ioctl(SIOCGIFFLAGS) error (%d): %s", strerror(errno));
return GETMAC_ERROR;
}