Linux 下 可以使用ioctl()函数 以及 结构体 struct ifreq
结构体struct ifconf来获取网络接口的各种信息。
ioctl
首先看ioctl()用法
ioctl()原型如下:
#include <sys/ioctl.h>
int ioctl(int fd, int request, ...);
参数:
fd : 文件描述符
request: 表示要请求的信息。如IP地址、网络掩码等
... : 后面的可变参数根据request而定
比如我们请求所有网络接口的清单:
-
struct ifconf IoCtlReq;
-
...
-
ioctl( Sock, SIOCGIFCONF, &IoCtlReq )
其中 IoCtlReq 是一个
与接口相关的request如下表所示( 来源: <
http://baike.baidu.com/view/1081282.htm?fr=aladdin
> ):
接
口
|
SIOCGIFCONF
SIOCSIFADDR
SIOCGIFADDR
SIOCSIFFLAGS
SIOCGIFFLAGS
SIOCSIFDSTADDR
SIOCGIFDSTADDR
SIOCGIFBRDADDR
SIOCSIFBRDADDR
SIOCGIFNETMASK
SIOCSIFNETMASK
SIOCGIFMETRIC
SIOCSIFMETRIC
SIOCGIFMTU
SIOCxxx
|
获取所有接口的清单
设置接口地址
获取接口地址
设置接口标志
获取接口标志
设置点到点地址
获取点到点地址
获取广播地址
设置广播地址
获取子网掩码
设置子网掩码
获取接口的测度
设置接口的测度
获取接口MTU
(还有很多取决于系统的实现)
|
struct ifconf
struct ifreq
struct ifreq
struct ifreq
struct ifreq
struct ifreq
struct ifreq
struct ifreq
struct ifreq
struct ifreq
struct ifreq
struct ifreq
struct ifreq
struct ifreq
|
关于ioctl的详细解释清查阅本博其它博文
struct ifreq
结构体 struct ifreq用来保存某个接口的信息。
-
// if.h
-
/*
-
* Interface request structure used for socket
-
* ioctl's. All interface ioctl's must have parameter
-
* definitions which begin with ifr_name. The
-
* remainder may be interface specific.
-
*/
-
struct ifreq {
-
#define IFHWADDRLEN 6
-
union
-
{
-
char ifrn_name[IFNAMSIZ];
/* if name, e.g. "en0" */
-
} ifr_ifrn;
-
-
union {
-
struct sockaddr ifru_addr;
-
struct sockaddr ifru_dstaddr;
-
struct sockaddr ifru_broadaddr;
-
struct sockaddr ifru_netmask;
-
struct sockaddr ifru_hwaddr;
-
short ifru_flags;
-
int ifru_ivalue;
-
int ifru_mtu;
-
struct ifmap ifru_map;
-
char ifru_slave[IFNAMSIZ];
/* Just fits the size */
-
char ifru_newname[IFNAMSIZ];
-
void __user * ifru_data;
-
struct if_settings ifru_settings;
-
} ifr_ifru;
-
};
-
#define ifr_name ifr_ifrn.ifrn_name /* interface name */
-
#define ifr_hwaddr ifr_ifru.ifru_hwaddr /* MAC address */
-
#define ifr_addr ifr_ifru.ifru_addr /* address */
-
#define ifr_dstaddr ifr_ifru.ifru_dstaddr /* other end of p-p lnk */
-
#define ifr_broadaddr ifr_ifru.ifru_broadaddr /* broadcast address */
-
#define ifr_netmask ifr_ifru.ifru_netmask /* interface net mask */
-
#define ifr_flags ifr_ifru.ifru_flags /* flags */
-
#define ifr_metric ifr_ifru.ifru_ivalue /* metric */
-
#define ifr_mtu ifr_ifru.ifru_mtu /* mtu */
-
#define ifr_map ifr_ifru.ifru_map /* device map */
-
#define ifr_slave ifr_ifru.ifru_slave /* slave device */
-
#define ifr_data ifr_ifru.ifru_data /* for use by interface */
-
#define ifr_ifindex ifr_ifru.ifru_ivalue /* interface index */
-
#define ifr_bandwidth ifr_ifru.ifru_ivalue /* link bandwidth */
-
#define ifr_qlen ifr_ifru.ifru_ivalue /* Queue length */
-
#define ifr_newname ifr_ifru.ifru_newname /* New name */
-
#define ifr_settings ifr_ifru.ifru_settings /* Device/proto settings*/
ifr_name 标识了某一接口。
可以通过ioctl获取该接口的信息。如:
ioctl(Sock, SIOCGIFNETMASK, &IfReq);//获取网络接口地址掩码
该代码需要先对IfReq->ifr_name赋值,然后获取与 IfReq->ifr_name向匹配的网络接口 的地址掩码
struct ifconf
结构体struct ifconf通常用来保存所有接口信息
-
// if.h
-
/*
-
* Structure used in SIOCGIFCONF request.
-
* Used to retrieve interface configuration
-
* for machine (useful for programs which
-
* must know all networks accessible).
-
*/
-
struct ifconf {
-
int ifc_len;
/* size of buffer */
-
union {
-
char __user *ifcu_buf;
-
struct ifreq __user *ifcu_req;
-
} ifc_ifcu;
-
};
-
#define ifc_buf ifc_ifcu.ifcu_buf /* buffer address */
-
#define ifc_req ifc_ifcu.ifcu_req /* array of structures */
该结构体可以用来获取所哟网络接口的名字和信息(不是全部信息,是ip地址)
Example:
-
#include <sys/types.h>
-
#include <sys/ioctl.h>
-
#include <sys/socket.h>
-
#include <net/if.h>
-
#include <stdio.h>
-
#include <stdlib.h>
-
#include <unistd.h>
-
#include <netdb.h>
-
#include <string.h>
-
#include <fcntl.h>
-
#include <string.h>
-
#include <errno.h>
-
typedef
uint32_t uint32;
-
#define MAX_IF 10
-
int
-
main
()
-
{
-
struct ifreq ifVec[MAX_IF];
//用来保存所有接口
-
-
int sock =
-1;
-
if ( (sock = socket( AF_INET, SOCK_DGRAM,
0 )) <
0 )
-
fprintf(
stderr,
"Error:%d, cannot open RAM;\n");
-
-
// get if vector
-
struct ifconf ioIfConf;
-
ioIfConf.ifc_buf = (
void *)ifVec;
-
ioIfConf.ifc_len =
sizeof(ifVec);
-
printf(
"Len:%d\n", ioIfConf.ifc_len);
-
-
if (ioctl(sock, SIOCGIFCONF, &ioIfConf) <
0 )
//获取所有网络接口信息
-
fprintf(
stderr,
"Error:%d ioctl IFCONF\n");
-
-
printf(
"Len:%d\n", ioIfConf.ifc_len);
// 和前面到len对比,发现ioctl修改里len到大小
-
//循环打印每个网络接口到信息
-
{
-
struct ifreq *ifPt;
-
struct ifreq *ifEndPt;
-
ifPt = ifVec;
-
ifEndPt = (
void *)((
char *)ifVec + ioIfConf.ifc_len);
-
for (ifPt = ifVec; ifPt < ifEndPt; ifPt++)
-
{
-
struct ifreq ifReq;
-
if ( ifPt->ifr_addr.sa_family != AF_INET ) {
-
continue;
-
}
-
-
// Temp keepers of interface params...
-
uint32 u32_addr, u32_mask;
-
-
/* 打印ip地址 */
-
char ipDotBuf[
16], subnetDotBuf[
16], maskDotBuf[
16];
// 保存点分十进制到ip地址
-
u32_addr = ((struct sockaddr_in *)&ifPt->ifr_addr)->sin_addr.s_addr;
-
inet_ntop(AF_INET, &u32_addr, ipDotBuf, (
socklen_t )
sizeof(ipDotBuf));
-
printf(
"IP Address: %s\n", ipDotBuf);
-
-
/* 打印地址掩码 */
-
bzero(&ifReq,
sizeof(struct ifreq));
-
memcpy(ifReq.ifr_name, ifPt->ifr_name,
sizeof(ifReq.ifr_name));
-
if (ioctl(sock, SIOCGIFNETMASK, &ifReq ) <
0){
-
fprintf(
stderr,
"Error: %d, cannot get mask\n", errno);
-
}
-
else{
-
u32_mask = ((struct sockaddr_in *)&ifReq.ifr_addr)->sin_addr.s_addr;
-
inet_ntop(AF_INET, &u32_mask, maskDotBuf, (
socklen_t )
sizeof(maskDotBuf));
-
printf(
"Mask: %s\n", maskDotBuf);
-
}
-
/* 打印MTU */
-
bzero(&ifReq,
sizeof(struct ifreq));
-
memcpy(ifReq.ifr_name, ifPt->ifr_name,
sizeof(ifReq.ifr_name));
-
if (ioctl(sock, SIOCGIFMTU, &ifReq ) <
0){
-
fprintf(
stderr,
"Error: %d, cannot get MTU\n", errno);
-
}
-
else{
-
printf(
"SIOCGIFMTU:%d\n", ifReq.ifr_mtu);
-
}
-
/* 其他信息的打印方式与掩码和MTU相同 */
-
}
-
}
-
-
-
-
}
运行结果:
-
windeal@ubuntu:~/Windeal/apue$ ./exe
-
Len:
320
-
Len:
64
-
IP Address:
127.0
.0
.1
-
Mask:
255.0
.0
.0
-
SIOCGIFMTU:
16436
-
IP Address:
172.17
.92
.198
-
Mask:
255.255
.254
.0
-
SIOCGIFMTU:
1500
-
windeal@ubuntu:~/Windeal/apue$
转自:https://blog.csdn.net/windeal3203/article/details/39320605#commentBox