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.使用方法非常easy,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;
        }

        
        if (ioctl (mi->fd, SIOCGIFADDR, (char *) & mi->buf[i])) {
            err->errcode = errno;
            snprintf (err->errmsg, GETMAC_MAX_MSGLEN, "ioctl(SIOCGIFADDR) error (%d): %s", strerror(errno));  
            return GETMAC_ERROR;
        }
        
        /* get Hardware Address */
#ifdef SOLARIS
        do {
            mi->arp.arp_pa.sa_family = AF_INET;
            mi->arp.arp_ha.sa_family = AF_INET;
            ((struct sockaddr_in *) & mi->arp.arp_pa)->sin_addr.s_addr = ((struct sockaddr_in*)(& buf[i].ifr_addr))->sin_addr.s_addr;

            if ((ioctl (mi->fd, SIOCGARP, (char *) & mi->arp))) {
                err->errcode = errno;
                snprintf (err->errmsg, GETMAC_MAX_MSGLEN, "ioctl(SIOCGARP) error (%d): %s", strerror(errno));  
                return GETMAC_ERROR;
            }
        } while (0);
#else
    #if 0
        do {
            /* get HW ADDRESS of the net card */
            if (ioctl (mi->fd, SIOCGENADDR, (char *) & buf[i])) {
                err->errcode = errno;
                snprintf (err->errmsg, GETMAC_MAX_MSGLEN, "ioctl(SIOCGENADDR) error (%d): %s", strerror(errno));  
                return GETMAC_ERROR;
            }
        } while (0);
    #else
        do {
            if (ioctl (mi->fd, SIOCGIFHWADDR, (char *) & mi->buf[i])) {
                err->errcode = errno;
                snprintf (err->errmsg, GETMAC_MAX_MSGLEN, "ioctl(SIOCGIFHWADDR) error (%d): %s", strerror(errno));  
                return GETMAC_ERROR;
            }
        } while (0);
    #endif
#endif       
    }

    err->errcode = GETMAC_NOERROR;

    /* get net attribute */
    switch (attr) {
    case GETMAC_ATTR_IFF_UP:    /* Interface is up */
        if (mi->buf[i].ifr_flags & IFF_UP) {
            * ((GETMAC_BOOL *) value) = GETMAC_TRUE;
            snprintf (err->errmsg, GETMAC_MAX_MSGLEN, "Interface is up");
        } else {
            * ((GETMAC_BOOL *) value) = GETMAC_FALSE;
            snprintf (err->errmsg, GETMAC_MAX_MSGLEN, "Interface is not up");
        }
        break;
    
    case GETMAC_ATTR_IFF_BROADCAST:    /* Broadcast address valid */
        if (mi->buf[i].ifr_flags & IFF_BROADCAST) {
            * ((GETMAC_BOOL *) value) = GETMAC_TRUE;
            snprintf (err->errmsg, GETMAC_MAX_MSGLEN, "Broadcast address valid");
        } else {
            * ((GETMAC_BOOL *) value) = GETMAC_FALSE;
            snprintf (err->errmsg, GETMAC_MAX_MSGLEN, "Broadcast address invalid");
        }
        break;
    
    case GETMAC_ATTR_IFF_DEBUG:    /* Turn on debugging */
        if (mi->buf[i].ifr_flags & IFF_DEBUG) {
            * ((GETMAC_BOOL *) value) = GETMAC_TRUE;
            snprintf (err->errmsg, GETMAC_MAX_MSGLEN, "Turn on debugging");
        } else {
            * ((GETMAC_BOOL *) value) = GETMAC_FALSE;
            snprintf (err->errmsg, GETMAC_MAX_MSGLEN, "Turn off debugging");
        }
        break;
    
    case GETMAC_ATTR_IFF_LOOPBACK:    /* Is a loopback net */
        if (mi->buf[i].ifr_flags & IFF_LOOPBACK) {
            * ((GETMAC_BOOL *) value) = GETMAC_TRUE;
            snprintf (err->errmsg, GETMAC_MAX_MSGLEN, "Is a loopback net");
        } else {
            * ((GETMAC_BOOL *) value) = GETMAC_FALSE;
            snprintf (err->errmsg, GETMAC_MAX_MSGLEN, "Not a loopback net");
        }
        break;
    
    case GETMAC_ATTR_IFF_POINTOPOINT:    /* Interface is point-to-point link */
        if (mi->buf[i].ifr_flags & IFF_POINTOPOINT) {
            * ((GETMAC_BOOL *) value) = GETMAC_TRUE;
            snprintf (err->errmsg, GETMAC_MAX_MSGLEN, "Interface is point-to-point link");
        } else {
            * ((GETMAC_BOOL *) value) = GETMAC_FALSE;
            snprintf (err->errmsg, GETMAC_MAX_MSGLEN, "Interface is not point-to-point link");
        }
        break;
    
    case GETMAC_ATTR_IFF_NOTRAILERS:    /* Avoid use of trailers */
        if (mi->buf[i].ifr_flags & IFF_NOTRAILERS) {
            * ((GETMAC_BOOL *) value) = GETMAC_TRUE;
            snprintf (err->errmsg, GETMAC_MAX_MSGLEN, "Avoid use of trailers");
        } else {
            * ((GETMAC_BOOL *) value) = GETMAC_FALSE;
            snprintf (err->errmsg, GETMAC_MAX_MSGLEN, "Not Avoid use of trailers");
        }
        break;
    
    case GETMAC_ATTR_IFF_RUNNING:    /* Resources allocated */
        if (mi->buf[i].ifr_flags & IFF_RUNNING) {
            * ((GETMAC_BOOL *) value) = GETMAC_TRUE;
            snprintf (err->errmsg, GETMAC_MAX_MSGLEN, "Resources allocated");
        } else {
            * ((GETMAC_BOOL *) value) = GETMAC_FALSE;
            snprintf (err->errmsg, GETMAC_MAX_MSGLEN, "Resources not allocated");
        }
        break;
    
    case GETMAC_ATTR_IFF_NOARP:    /* No address resolution protocol */
        if (mi->buf[i].ifr_flags & IFF_NOARP) {
            * ((GETMAC_BOOL *) value) = GETMAC_TRUE;
            snprintf (err->errmsg, GETMAC_MAX_MSGLEN, "No address resolution protocol");
        } else {
            * ((GETMAC_BOOL *) value) = GETMAC_FALSE;
            snprintf (err->errmsg, GETMAC_MAX_MSGLEN, "Has address resolution protocol");
        }   
        break;

    case GETMAC_ATTR_IFF_PROMISC:    /* Receive all packets */
        if (mi->buf[i].ifr_flags & IFF_PROMISC) {
            * ((GETMAC_BOOL *) value) = GETMAC_TRUE;
            snprintf (err->errmsg, GETMAC_MAX_MSGLEN, "Receive all packets");
        } else {
            * ((GETMAC_BOOL *) value) = GETMAC_FALSE;
            snprintf (err->errmsg, GETMAC_MAX_MSGLEN, "Not a promisc mode");
        }
        break;

    case GETMAC_ATTR_IFNAME:    /* Interface name, e.g. "en0" */
        strcpy (value, mi->buf[i].ifr_name);
        snprintf (err->errmsg, GETMAC_MAX_MSGLEN, "Interface name");
        break;
    
    case GETMAC_ATTR_IPADDR:    /* Interface address */
        strcpy (value, inet_ntoa (((struct sockaddr_in*) (& mi->buf[i].ifr_addr))->sin_addr));
        snprintf (err->errmsg, GETMAC_MAX_MSGLEN, "Interface address");
        break;
    
    case GETMAC_ATTR_HWADDR:
#ifdef SOLARIS
        do {
            mi->arp.arp_pa.sa_family = AF_INET;
            mi->arp.arp_ha.sa_family = AF_INET;

            ((struct sockaddr_in *) & mi->arp.arp_pa)->sin_addr.s_addr = ((struct sockaddr_in*)(& buf[i].ifr_addr))->sin_addr.s_addr;

            if ((ioctl (mi->fd, SIOCGARP, (char *) & mi->arp))) {
                err->errcode = errno;
                snprintf (err->errmsg, GETMAC_MAX_MSGLEN, "ioctl(SIOCGARP) error (%d): %s", strerror(errno));  
                return GETMAC_ERROR;
            } else {
                sprintf (value, "%02x:%02x:%02x:%02x:%02x:%02x",
                    (unsigned char) mi->arp.arp_ha.sa_data[0],
                    (unsigned char) mi->arp.arp_ha.sa_data[1],
                    (unsigned char) mi->arp.arp_ha.sa_data[2],
                    (unsigned char) mi->arp.arp_ha.sa_data[3],
                    (unsigned char) mi->arp.arp_ha.sa_data[4],
                    (unsigned char) mi->arp.arp_ha.sa_data[5] );
            }
        } while (0);
#else
    #if 0
        do {
            sprintf("%02x:%02x:%02x:%02x:%02x:%02x",
                (unsigned char) mi->buf[i].ifr_enaddr[0],
                (unsigned char) mi->buf[i].ifr_enaddr[1],
                (unsigned char) mi->buf[i].ifr_enaddr[2],
                (unsigned char) mi->buf[i].ifr_enaddr[3],
                (unsigned char) mi->buf[i].ifr_enaddr[4],
                (unsigned char) mi->buf[i].ifr_enaddr[5]);
        } while (0);
    #else
        do {
            sprintf (value, "%02x:%02x:%02x:%02x:%02x:%02x",
                (unsigned char) mi->buf[i].ifr_hwaddr.sa_data[0],
                (unsigned char) mi->buf[i].ifr_hwaddr.sa_data[1],
                (unsigned char) mi->buf[i].ifr_hwaddr.sa_data[2],
                (unsigned char) mi->buf[i].ifr_hwaddr.sa_data[3],
                (unsigned char) mi->buf[i].ifr_hwaddr.sa_data[4],
                (unsigned char) mi->buf[i].ifr_hwaddr.sa_data[5]);
        } while (0);
    #endif
#endif
        snprintf (err->errmsg, GETMAC_MAX_MSGLEN, "MAC address");
        break;

    default:
        err->errcode = GETMAC_EATTR;
        snprintf (err->errmsg, GETMAC_MAX_MSGLEN, "error attr specified");
        return GETMAC_EATTR;
    }

    return GETMAC_SUCCESS;
}


void getmac_fini (getmac_info_t * mi)
{
    if (mi->fd != -1) {
        close (mi->fd);
        mi->fd = -1;
    }
}