#include //printf()

#include //ioctl()

#include //ioctl

#include //socket()

#include //struct ifconf{} & struct ifreq{}

#include //strcpy()

#include //inet_ntoa()

#include //malloc() & free()

int print_if_addr(int fd, char *interface_name); //打印接口的ip地址

int print_if_mac(int fd, char *interface_name); //打印接口的mac地址

int print_if_broadaddr(int fd, char *interface_name); //打印接口的广播地址

int print_if_mask(int fd, char *interface_name); //打印接口的掩码

int print_if_mtu(int fd, char *interface_name); //打印接口的mtu

int print_all_interface(); //打印所有接口的基本信息

int print_if_addr6(char *interface_name); //打印接口的ipv6地址

int print_interface_info(char *interface_name); //打印接口的以上所有信息

int set_if_up(char *interface_name); //启动接口

int set_if_down(char *interface_name); //关闭接口

int set_if_ip(char *interface_name, char *ip_str); //设置接口的ip地址

void usage(); //打印该程序的使用手册

int main(int argc, char **argv)

{

int sockfd;

switch(argc)

{

case 1:

print_all_interface();

break;

case 2:

print_interface_info(argv[1]);

break;

case 3:

if(strcmp(argv[2], "up") == 0)

set_if_up(argv[1]);

else if(strcmp(argv[2], "down") == 0)

set_if_down(argv[1]);

else

set_if_ip(argv[1], argv[2]);

break;

default:

usage();

break;

}

return 0;

}

void usage()

{

printf("usage: ./myifconfig [interface [down|up|ip]]\n");

}

int print_if_addr(int fd, char *if_name)

{

struct sockaddr_in *ip;

struct ifreq ifr;

strcpy(ifr.ifr_name, if_name);

if(ioctl(fd, SIOCGIFADDR, &ifr) < 0)

{

perror("ioctl SIOCGIFADDR error");

return -1;

}

ip = (struct sockaddr_in *)&ifr.ifr_addr; //获得ipv4地址

printf(" IP: %s\n", inet_ntoa(ip->sin_addr)); //将ipv4地址转换为主机字节序的字符串并输出

return 0;

}

int print_if_broadaddr(int fd, char *if_name)

{

struct sockaddr_in *ip;

struct ifreq ifr;

strcpy(ifr.ifr_name, if_name);

if(ioctl(fd, SIOCGIFBRDADDR, &ifr) < 0)

{

perror("ioctl SIOCGIFBRDADDR error");

return -1;

}

ip = (struct sockaddr_in *)&ifr.ifr_broadaddr; //获得广播地址

printf(" Broadcast: %s\n", inet_ntoa(ip->sin_addr));

return 0;

}

int print_if_mask(int fd, char *if_name)

{

struct sockaddr_in *ip;

struct ifreq ifr;

strcpy(ifr.ifr_name, if_name);

if(ioctl(fd, SIOCGIFNETMASK, &ifr) < 0)

{

perror("ioctl SIOCGIFNETMASK error");

return -1;

}

ip = (struct sockaddr_in *)&ifr.ifr_ifru.ifru_netmask; //获得子网掩码。注意！我们仍放在struct aockaddr_in结构中返回

printf(" Mask: %s\n", inet_ntoa(ip->sin_addr));

return 0;

}

int print_if_mac(int fd, char *if_name)

{

unsigned char *p; //注意！ 这里要用unsigned char，而不是char！因为char要对[1xxx xxxx]这样的数进行补码运算的。

//但我们等下要打印的mac地址是不需要符号的数值

struct ifreq ifr;

strcpy(ifr.ifr_name, if_name);

if(ioctl(fd, SIOCGIFHWADDR, &ifr) < 0)

{

perror("ioctl SIOCGIFHWADDR error");

return -1;

}

p = (char *)&ifr.ifr_ifru.ifru_hwaddr.sa_data[0]; //获得接口的MAC地址，用字符串指针返回

printf(" MAC: %02x:%02x:%02x:%02x:%02x:%02x\n", *p, *(p+1), *(p+2), *(p+3), *(p+4), *(p+5));

//printf(" MAC:%02x:%02x:%02x:%02x:%02x:%02x/n", *p++, *p++, *p++, *p++, *p++, *p++);

//这么写会导致输出为倒序。这并不是p指针有什么问题，不信你可以用

// for(;;)

// printf(p++);

//来试验就是正确的，我猜倒序的原因是编译器的优化问题吧

return 0;

}

int print_if_mtu(int fd, char *if_name)

{

unsigned int mtu;

struct ifreq ifr;

strcpy(ifr.ifr_name, if_name);

if(ioctl(fd, SIOCGIFMTU, &ifr) < 0)

{

perror("ioctl SIOCGIFMTU error");

return -1;

}

mtu = ifr.ifr_ifru.ifru_mtu; //获得子网掩码。注意！我们仍放在struct aockaddr_in结构中返回

printf(" MTU: %d\n", mtu);

return 0;

}

int print_if_addr6(char *if_name)

{

unsigned int mtu;

struct ifreq ifr;

int sockfd;

if((sockfd = socket(AF_INET6, SOCK_DGRAM, 0)) < 0)

{

perror("Socket error");

return -1;

} // 创建用来检查网络接口的套接字

/* strcpy(ifr.ifr_name, if_name);

if(ioctl(fd, SIOCGIFMTU, &ifr) < 0)

{

perror("ioctl SIOCGIFMTU error");

return -1;

}

mtu = ifr.ifr_ifru.ifru_mtu; //获得子网掩码。注意！我们仍放在struct aockaddr_in结构中返回

printf(" ipv6: %d/n", mtu);

*/

//未写完，不知道怎么获得ipv6地址。。。

return 0;

}

int print_all_interface()

{

struct ifconf ifc;

struct ifreq *ifr_p;

int sockfd, len, old_len = 0, i;

char *buf;

if((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0)

{

perror("Socket error");

return -1;

} // 创建用来检查网络接口的套接字

len = 10 * sizeof(struct ifreq);

for( ; ; )

{

if((buf = malloc(len)) == NULL)

{

perror("malloc error");

return -1;

}

ifc.ifc_len = len;

ifc.ifc_buf = buf;

if(ioctl(sockfd, SIOCGIFCONF, &ifc) < 0)

{

perror("ioctl SIOCGIFCONF error");

return -1;

}

if(ifc.ifc_len == old_len)

break;

old_len = ifc.ifc_len;

len += 10 * sizeof(struct ifreq);

free(buf);

}

printf("we have %d Interfaces\n", ifc.ifc_len / sizeof(struct ifreq));

for(i = 0; i < ifc.ifc_len / sizeof(struct ifreq); i++)

{

ifr_p = &ifc.ifc_req[i];

printf(" Interface [%s]:\n", ifr_p->ifr_name);

print_if_addr(sockfd, ifr_p->ifr_name);

print_if_broadaddr(sockfd, ifr_p->ifr_name);

print_if_mask(sockfd, ifr_p->ifr_name);

print_if_mac(sockfd, ifr_p->ifr_name);

print_if_mtu(sockfd, ifr_p->ifr_name);

}

close(sockfd);

return 0;

}

int print_interface_info(char *if_name)

{

int sockfd;

if((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0)

{

perror("Socket error");

return -1;

} // 创建用来检查网络接口的套接字

printf("%s:\n", if_name);

print_if_addr(sockfd, if_name);

print_if_broadaddr(sockfd, if_name);

print_if_mask(sockfd, if_name);

print_if_mac(sockfd, if_name);

print_if_mtu(sockfd, if_name);

close(sockfd);

return 0;

}

int set_if_up(char *if_name) //启动接口

{

struct ifreq ifr;

int sockfd;

if((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0)

{

perror("Socket error");

return -1;

} // 创建用来检查网络接口的套接字

strcpy(ifr.ifr_name, if_name);

if(ioctl(sockfd, SIOCGIFFLAGS, &ifr) < 0)

{

perror("ioctl SIOCGIFFLAGS error");

return -1;

}

ifr.ifr_flags |= IFF_UP;

if(ioctl(sockfd, SIOCSIFFLAGS, &ifr) < 0)

{

perror("ioctl SIOCSIFFLAGS error");

return -1;

}

return 0;

}

int set_if_down(char *if_name) //关闭接口

{

struct ifreq ifr;

int sockfd;

if((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0)

{

perror("Socket error");

return -1;

} // 创建用来检查网络接口的套接字

strcpy(ifr.ifr_name, if_name);

if(ioctl(sockfd, SIOCGIFFLAGS, &ifr) < 0)

{

perror("ioctl SIOCGIFFLAGS error");

return -1;

}

ifr.ifr_flags &= ~IFF_UP; //将IIF_UP取反后与原来的标志进行 与运算。

if(ioctl(sockfd, SIOCSIFFLAGS, &ifr) < 0)

{

perror("ioctl SIOCSIFFLAGS error");

return -1;

}

return 0;

}

int set_if_ip(char *if_name, char *ip_str) //设置接口的ip地址

{

struct ifreq ifr;

struct sockaddr_in ip_addr;

int sockfd;

if((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0)

{

perror("Socket error");

return -1;

} // 创建用来检查网络接口的套接字

ip_addr.sin_family = AF_INET;

if(inet_pton(AF_INET, ip_str, &ip_addr.sin_addr) < 1)

{

perror("error ipv4 addr:");

return -1;

}

strcpy(ifr.ifr_name, if_name);

memcpy(&ifr.ifr_addr, &ip_addr, sizeof(struct sockaddr_in));

if(ioctl(sockfd, SIOCSIFADDR, &ifr) < 0)

{

perror("ioctl SIOCSIFADDR error");

return -1;

}

return 0;

}