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網絡子係統28_橋接ioctl
// 1.網橋子係統向用戶空間提供的接口：
// 1.1 通過socket ioctl創建網橋
// 1.2 通過網橋的特殊設備文件ioctl添加網橋端口
// 橋接在socket ioctl中的銜接處理
// 處理的命令類型：
// 1.獲取網橋信息
// 2.設置網橋信息
// 3.添加網橋
// 4.刪除網橋
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)//如果鉤子函數沒有被設置，則加載橋接模塊
request_module("bridge");
down(&br_ioctl_mutex);//在執行鉤子函數的過程中，獲取信號量，防止在鉤子函數被執行的過程，被設置
if (br_ioctl_hook)
err = br_ioctl_hook(cmd, argp);
up(&br_ioctl_mutex);
break;
...
}
// 網橋的socket ioctl
// 在網橋子係統初始化時，由brioctl_set設置br_ioctl_hook = br_ioctl_deviceless_stub
// 調用路徑: 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);//老式網橋命令
case SIOCBRADDBR://新網橋命令，添加或刪除網橋
case SIOCBRDELBR:
{
char buf[IFNAMSIZ];
if (!capable(CAP_NET_ADMIN))//當前進程需要admin權限
return -EPERM;
if (copy_from_user(buf, uarg, IFNAMSIZ))//uarg提供網橋名字
return -EFAULT;
buf[IFNAMSIZ-1] = 0;//c格式字符串
if (cmd == SIOCBRADDBR)//添加網橋
return br_add_bridge(buf);
return br_del_bridge(buf);//刪除
}
}
return -EOPNOTSUPP;
}
// 網橋老式ioctl命令處理
// 處理的命令類型為SIOCGIFBR, SIOCSIFBR
// 調用路徑: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)))//從用戶空間拷貝參數
return -EFAULT;
switch (args[0]) {//由uarg[0]提供命令
case BRCTL_GET_VERSION://獲取網橋版本
return BRCTL_VERSION;
case BRCTL_GET_BRIDGES://獲取網橋接口的index
{
int *indices;
int ret = 0;
indices = kmalloc(args[2]*sizeof(int), GFP_KERNEL);//uarg[2]指示獲取接口數
if (indices == NULL)
return -ENOMEM;
memset(indices, 0, args[2]*sizeof(int));
args[2] = get_bridge_ifindices(indices, args[2]);//實際獲取到的接口數
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://添加或刪除網橋，網橋名主機內唯一
case BRCTL_DEL_BRIDGE:
{
char buf[IFNAMSIZ];
if (!capable(CAP_NET_ADMIN))//當前進程admin權限
return -EPERM;
if (copy_from_user(buf, (void __user *)args[1], IFNAMSIZ))//uarg[1]保存網橋名的內存地址
return -EFAULT;
buf[IFNAMSIZ-1] = 0;//c風格字符串
if (args[0] == BRCTL_ADD_BRIDGE)
return br_add_bridge(buf);//添加網橋
return br_del_bridge(buf);//刪除網橋
}
}
return -EOPNOTSUPP;
}
// 網橋的特殊設備文件ioctl處理
// 通過打開網橋設備文件，ioctl
// 處理的命令：
// 1.老式網橋命令
// 2.新式添加刪除網橋端口命令
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://添加刪除接口
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;
}
// 遺留的老式設備文件ioctl
// 通過cmd=SIOCDEVPRIVATE調用
// 調用路徑：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]) {//刪除添加接口
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;
//獲取網橋設備信息
...
if (copy_to_user((void __user *)args[1], &b, sizeof(b)))
return -EFAULT;
return 0;
}
case BRCTL_GET_PORT_LIST://獲取網橋端口鏈表
{
int num, *indices;
...
//返回網橋端口的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://設置狀態轉移時間間隔
if (!capable(CAP_NET_ADMIN))//當前進程需要admin權限
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://設置hello時間間隔
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://轉發項的老化時間
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://啟動或關閉stp
if (!capable(CAP_NET_ADMIN))
return -EPERM;
br->stp_enabled = args[1]?1:0;
return 0;
case BRCTL_SET_BRIDGE_PRIORITY://設置網橋的優先級
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://設置端口的優先級
{
struct net_bridge_port *p;
int ret = 0;
if (!capable(CAP_NET_ADMIN))
return -EPERM;
if (args[2] >= (1<<(16-BR_PORT_BITS)))//2字節中，端口號使用的位數
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://設置路徑開銷
{
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://獲取轉發項的個數
return get_fdb_entries(br, (void __user *)args[1],
args[2], args[3]);
}
return -EOPNOTSUPP;
}
最後更新：2017-04-03 15:22:11