一、ifconf和ifreq结构
//ifconf通常是用来保存所有接口信息的
//if.h
struct ifconf
{
int ifc_len; /* size of buffer */
union
{
char *ifcu_buf; /* input from user->kernel*/
struct ifreq *ifcu_req; /* return from kernel->user*/
} ifc_ifcu;
};
#define ifc_buf ifc_ifcu.ifcu_buf /* buffer address */
#define ifc_req ifc_ifcu.ifcu_req /* array of structures */
//ifreq用来保存某个接口的信息
//if.h
struct ifreq
{
char ifr_name[IFNAMSIZ];
union
{
struct sockaddr ifru_addr;
struct sockaddr ifru_dstaddr;
struct sockaddr ifru_broadaddr;
short ifru_flags;
int ifru_metric;
caddr_t ifru_data;
} ifr_ifru;
};
#define ifr_addr ifr_ifru.ifru_addr
#define ifr_dstaddr ifr_ifru.ifru_dstaddr
#define ifr_broadaddr ifr_ifru.ifru_broadaddr
二、使用示例
/************************
file: test.c
funtion: get all interfaces info
************************/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ipc.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <net/if.h>
#include <sys/types.h>
#include <sys/ioctl.h>
unsigned char buf[512];
int main()
{
struct ifconf myconf;
struct ifreq *myreq;
int sockfd;
int i;
myconf.ifc_len = 512;
myconf.ifc_buf = buf;
if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
{
perror("socket failed.\n");
exit(1);
}
ioctl(sockfd, SIOCGIFCONF, &myconf);
myreq = (struct ifreq *)buf;
printf("len: %d\n", myconf.ifc_len);
for (i=0; i<(myconf.ifc_len/sizeof(struct ifreq)); i++)
{
printf("name: %s\n", myreq->ifr_name);
printf("local addr: %s\n", inet_ntoa(((struct sockaddr_in *)&(myreq->ifr_addr))->sin_addr));
myreq++;
}
close(sockfd);
return 0;
}
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