通过Socket configuration controls 获取网络设备地址

常用的头文件, 基本通用了.

#ifndef _INC_H
#define _INC_H

#include <stdio.h>
#include <errno.h>
#include <time.h>
#include <signal.h>
#include <stdint.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>

#include <getopt.h>
#include <inttypes.h>

#include <sys/types.h>
#include <sys/time.h>
#include <sys/file.h>

#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#include <netinet/in_systm.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/ip_icmp.h>
#include <arpa/inet.h>
#include <netdb.h>

#include <sys/select.h>

#include <net/if.h>
#include <sys/ioctl.h>
#endif

代码实现:

其他Socket configuration controls可以在/usr/include/bits/ioctls.h中查看到.

static int iface_sock = -1;
int iface_init(void)
{
	int sock = -1;
	sock = socket( AF_INET, SOCK_DGRAM, 0 );
    if ( sock < 0 ) {
        fprintf( stderr, "create socket for iface fail.\n" );
        return -1;
    }
    iface_sock = sock;
    return 0;
}

void iface_destory(void)
{
	if ( iface_sock < 0 )
		return ;
		
	close( iface_sock );
}


int iface_address_by_name(char *devname, uint32_t *addr)
{
	int err = -1; 
	struct ifreq ifr;
	
    if ( iface_sock < 0 ) {
        goto _out;
    }

    strcpy( ifr.ifr_name, devname );
    
    err = ioctl( iface_sock, SIOCGIFADDR, &ifr, sizeof( ifr ) );
    if ( err < 0 ) {
        goto _out;
    }

	printf( "DEBUG: NIC-%s: %s\n", devname, 
		inet_ntoa( ((struct sockaddr_in *)( &ifr.ifr_addr ))->sin_addr ) );
	if ( addr ) {
		*addr = ((struct sockaddr_in *)( &ifr.ifr_addr ))->sin_addr.s_addr;
	}
	err = 0;

_out:
    return err;	
}
int iface_address_by_index(uint32_t index, uint32_t *addr)
{
	int err = -1;
	struct ifreq ifr;

    if ( iface_sock < 0 ) {
        goto _out;
    }

	ifr.ifr_ifindex = index;
	    
    err = ioctl( iface_sock, SIOCGIFADDR, &ifr, sizeof( ifr ) );
    if ( err < 0 ) {
        goto _out;
    }

	printf( "NIC-%u-: ip=%s\n", index, 
		inet_ntoa( ((struct sockaddr_in *)( &ifr.ifr_addr ))->sin_addr ) );
	if ( addr ) {
		*addr = ((struct sockaddr_in *)( &ifr.ifr_addr ))->sin_addr.s_addr;
	}
	err = 0;

_out:
    return err;	
}

int lookup_nic_address(char *devname, uint32_t *addr)
{
    int err = -1;
    int sock = 0;
    struct ifconf ifcs;
	struct ifreq *ifr;

    sock = socket( AF_INET, SOCK_DGRAM, 0 );
    if ( sock < 0 ) {
        goto _out;
    }

    ifcs.ifc_len = 0;
    ifcs.ifc_req = NULL;

    err = ioctl( sock, SIOCGIFCONF, &ifcs, sizeof( ifcs ) );
    if ( err < 0 ) {
        goto _out;
    }

    if ( ifcs.ifc_len > 0 ) {
        ifcs.ifc_req = malloc(ifcs.ifc_len);
        if (ifcs.ifc_req) {

            if (ioctl(sock, SIOCGIFCONF, &ifcs, sizeof( ifcs ) ) < 0) {
                free(ifcs.ifc_req);
                goto _out;
            } else {
                for (ifr = ifcs.ifc_req;
                        (char *)ifr <
                        (char *)ifcs.ifc_req + ifcs.ifc_len; ++ifr) {
                    /*printf("%s\n", ifr->ifr_name);*/
                    if (!strcmp(ifr->ifr_name, devname )) {
                    	
                    	printf( "INIT: NIC-%s index=%u ip=%s\n", devname, 
								ifr->ifr_ifindex,
								inet_ntoa( ((struct sockaddr_in *)( &ifr->ifr_addr ))->sin_addr ) );
                    	if ( addr ) {
                    		*addr = ((struct sockaddr_in *)( &ifr->ifr_addr ))->sin_addr.s_addr;
                    	}
                        err = 0;
                        break;
                    }
                }
                free(ifcs.ifc_req);
            }
        }
    }

_out:
    if ( sock > 0 ) {
        close( sock );
    }
    return err;
}