该篇实例是摘自网络（无法追根溯源倒低是哪位“前”辈写的了）
一、应用层
uint16 data16;
if ((fd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
{
printf("socket failed ");
}
if(ioctl(fd, SIOCSIFVLAN_PVID_PRI, &data16) < 0)
{
printf("ioctl pvid failed ");
}
二、linux内核
1、 在sockios.h中定义
#define SIOCSIFVLAN_PVID_PRI 0x8985 /* Set 802.1Q VLAN pvid */
2、在af_inet.c中
添加
extern int VLAN1QEN(unsigned int ,void *arg);
在inet_ioctl()函数中添加
case SIOCSIFVLAN_PVID_PRI:
return VLAN1QEN(cmd, arg);
3、另外定义：
static unsigned int VLAN_PVID_PRI = 0;
int VLAN1QEN(unsigned int cmd,void *arg)
{
unsigned int data;
if (copy_from_user(&data, arg, sizeof(int)))
return -EFAULT;
switch (cmd) {
case SIOCSIFVLAN_PVID_PRI:
VLAN_PVID_PRI = data;
break;
default:
return -EINVAL;
}
}