258
网络子系统28_桥接ioctl
// 1.网桥子系统向用户空间提供的接口：
// 1.1 通过socket ioctl创建网桥
// 1.2 通过网桥的特殊设备文件ioctl添加网桥端口
// 桥接在socket ioctl中的衔接处理
// 处理的命令类型：
// 1.获取网桥信息
// 2.设置网桥信息
// 3.添加网桥
// 4.删除网桥
1.1 static long sock_ioctl(struct file *file, unsigned cmd, unsigned long arg)
{
...
case SIOCGIFBR:
case SIOCSIFBR:
case SIOCBRADDBR:
case SIOCBRDELBR:
err = -ENOPKG;
if (!br_ioctl_hook)//如果钩子函数没有被设置，则加载桥接模块
request_module("bridge");
down(&br_ioctl_mutex);//在执行钩子函数的过程中，获取信号量，防止在钩子函数被执行的过程，被设置
if (br_ioctl_hook)
err = br_ioctl_hook(cmd, argp);
up(&br_ioctl_mutex);
break;
...
}
// 网桥的socket ioctl
// 在网桥子系统初始化时，由brioctl_set设置br_ioctl_hook = br_ioctl_deviceless_stub
// 调用路径: sock_ioctl->br_ioctl_hook
1.2 int br_ioctl_deviceless_stub(unsigned int cmd, void __user *uarg)
{
switch (cmd) {
case SIOCGIFBR:
case SIOCSIFBR:
return old_deviceless(uarg);//老式网桥命令
case SIOCBRADDBR://新网桥命令，添加或删除网桥
case SIOCBRDELBR:
{
char buf[IFNAMSIZ];
if (!capable(CAP_NET_ADMIN))//当前进程需要admin权限
return -EPERM;
if (copy_from_user(buf, uarg, IFNAMSIZ))//uarg提供网桥名字
return -EFAULT;
buf[IFNAMSIZ-1] = 0;//c格式字符串
if (cmd == SIOCBRADDBR)//添加网桥
return br_add_bridge(buf);
return br_del_bridge(buf);//删除
}
}
return -EOPNOTSUPP;
}
// 网桥老式ioctl命令处理
// 处理的命令类型为SIOCGIFBR, SIOCSIFBR
// 调用路径:br_ioctl_deviceless_stub->old_deviceless
1.3 static int old_deviceless(void __user *uarg)
{
unsigned long args[3];
if (copy_from_user(args, uarg, sizeof(args)))//从用户空间拷贝参数
return -EFAULT;
switch (args[0]) {//由uarg[0]提供命令
case BRCTL_GET_VERSION://获取网桥版本
return BRCTL_VERSION;
case BRCTL_GET_BRIDGES://获取网桥接口的index
{
int *indices;
int ret = 0;
indices = kmalloc(args[2]*sizeof(int), GFP_KERNEL);//uarg[2]指示获取接口数
if (indices == NULL)
return -ENOMEM;
memset(indices, 0, args[2]*sizeof(int));
args[2] = get_bridge_ifindices(indices, args[2]);//实际获取到的接口数
ret = copy_to_user((void __user *)args[1], indices, args[2]*sizeof(int))//uarg[1]包含保存返回值的位置
? -EFAULT : args[2];
kfree(indices);
return ret;
}
case BRCTL_ADD_BRIDGE://添加或删除网桥，网桥名主机内唯一
case BRCTL_DEL_BRIDGE:
{
char buf[IFNAMSIZ];
if (!capable(CAP_NET_ADMIN))//当前进程admin权限
return -EPERM;
if (copy_from_user(buf, (void __user *)args[1], IFNAMSIZ))//uarg[1]保存网桥名的内存地址
return -EFAULT;
buf[IFNAMSIZ-1] = 0;//c风格字符串
if (args[0] == BRCTL_ADD_BRIDGE)
return br_add_bridge(buf);//添加网桥
return br_del_bridge(buf);//删除网桥
}
}
return -EOPNOTSUPP;
}
// 网桥的特殊设备文件ioctl处理
// 通过打开网桥设备文件，ioctl
// 处理的命令：
// 1.老式网桥命令
// 2.新式添加删除网桥端口命令
2.1 int br_dev_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
{
struct net_bridge *br = netdev_priv(dev);
switch(cmd) {
case SIOCDEVPRIVATE://老式命令
return old_dev_ioctl(dev, rq, cmd);
case SIOCBRADDIF://添加删除接口
case SIOCBRDELIF:
return add_del_if(br, rq->ifr_ifindex, cmd == SIOCBRADDIF);
}
pr_debug("Bridge does not support ioctl 0x%x\n", cmd);
return -EOPNOTSUPP;
}
// 遗留的老式设备文件ioctl
// 通过cmd=SIOCDEVPRIVATE调用
// 调用路径：br_dev_ioctl->old_dev_ioctl
2.2 static int old_dev_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
{
struct net_bridge *br = netdev_priv(dev);
unsigned long args[4];
if (copy_from_user(args, rq->ifr_data, sizeof(args)))
return -EFAULT;
switch (args[0]) {//删除添加接口
case BRCTL_ADD_IF:
case BRCTL_DEL_IF:
return add_del_if(br, args[1], args[0] == BRCTL_ADD_IF);
case BRCTL_GET_BRIDGE_INFO:
{
struct __bridge_info b;
//获取网桥设备信息
...
if (copy_to_user((void __user *)args[1], &b, sizeof(b)))
return -EFAULT;
return 0;
}
case BRCTL_GET_PORT_LIST://获取网桥端口链表
{
int num, *indices;
...
//返回网桥端口的index
get_port_ifindices(br, indices, num);
if (copy_to_user((void __user *)args[1], indices, num*sizeof(int)))
num = -EFAULT;
kfree(indices);
return num;
}
case BRCTL_SET_BRIDGE_FORWARD_DELAY://设置状态转移时间间隔
if (!capable(CAP_NET_ADMIN))//当前进程需要admin权限
return -EPERM;
spin_lock_bh(&br->lock);
br->bridge_forward_delay = clock_t_to_jiffies(args[1]);
if (br_is_root_bridge(br))
br->forward_delay = br->bridge_forward_delay;
spin_unlock_bh(&br->lock);
return 0;
case BRCTL_SET_BRIDGE_HELLO_TIME://设置hello时间间隔
if (!capable(CAP_NET_ADMIN))
return -EPERM;
spin_lock_bh(&br->lock);
br->bridge_hello_time = clock_t_to_jiffies(args[1]);
if (br_is_root_bridge(br))
br->hello_time = br->bridge_hello_time;
spin_unlock_bh(&br->lock);
return 0;
case BRCTL_SET_BRIDGE_MAX_AGE://BPDU信息的生存期
if (!capable(CAP_NET_ADMIN))
return -EPERM;
spin_lock_bh(&br->lock);
br->bridge_max_age = clock_t_to_jiffies(args[1]);
if (br_is_root_bridge(br))
br->max_age = br->bridge_max_age;
spin_unlock_bh(&br->lock);
return 0;
case BRCTL_SET_AGEING_TIME://转发项的老化时间
if (!capable(CAP_NET_ADMIN))
return -EPERM;
br->ageing_time = clock_t_to_jiffies(args[1]);
return 0;
case BRCTL_GET_PORT_INFO://端口信息
{
struct __port_info p;
struct net_bridge_port *pt;
rcu_read_lock();
if ((pt = br_get_port(br, args[2])) == NULL) {
rcu_read_unlock();
return -EINVAL;
}
....
rcu_read_unlock();
if (copy_to_user((void __user *)args[1], &p, sizeof(p)))
return -EFAULT;
return 0;
}
case BRCTL_SET_BRIDGE_STP_STATE://启动或关闭stp
if (!capable(CAP_NET_ADMIN))
return -EPERM;
br->stp_enabled = args[1]?1:0;
return 0;
case BRCTL_SET_BRIDGE_PRIORITY://设置网桥的优先级
if (!capable(CAP_NET_ADMIN))
return -EPERM;
spin_lock_bh(&br->lock);
br_stp_set_bridge_priority(br, args[1]);
spin_unlock_bh(&br->lock);
return 0;
case BRCTL_SET_PORT_PRIORITY://设置端口的优先级
{
struct net_bridge_port *p;
int ret = 0;
if (!capable(CAP_NET_ADMIN))
return -EPERM;
if (args[2] >= (1<<(16-BR_PORT_BITS)))//2字节中，端口号使用的位数
return -ERANGE;
spin_lock_bh(&br->lock);
if ((p = br_get_port(br, args[1])) == NULL)
ret = -EINVAL;
else
br_stp_set_port_priority(p, args[2]);
spin_unlock_bh(&br->lock);
return ret;
}
case BRCTL_SET_PATH_COST://设置路径开销
{
struct net_bridge_port *p;
int ret = 0;
if (!capable(CAP_NET_ADMIN))
return -EPERM;
spin_lock_bh(&br->lock);
if ((p = br_get_port(br, args[1])) == NULL)
ret = -EINVAL;
else
br_stp_set_path_cost(p, args[2]);
spin_unlock_bh(&br->lock);
return ret;
}
case BRCTL_GET_FDB_ENTRIES://获取转发项的个数
return get_fdb_entries(br, (void __user *)args[1],
args[2], args[3]);
}
return -EOPNOTSUPP;
}
最后更新：2017-04-03 15:22:11