2 * trelay.c: Trivial Ethernet Relay
4 * Copyright (C) 2012 Felix Fietkau <nbd@openwrt.org>
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version 2
9 * of the License, or (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 #include <linux/module.h>
17 #include <linux/list.h>
18 #include <linux/mutex.h>
19 #include <linux/netdevice.h>
20 #include <linux/rtnetlink.h>
21 #include <linux/debugfs.h>
23 static LIST_HEAD(trelay_devs);
24 static struct dentry *debugfs_dir;
27 struct list_head list;
28 struct net_device *dev1, *dev2;
29 struct dentry *debugfs;
33 rx_handler_result_t trelay_handle_frame(struct sk_buff **pskb)
35 struct net_device *dev;
36 struct sk_buff *skb = *pskb;
38 dev = rcu_dereference(skb->dev->rx_handler_data);
40 return RX_HANDLER_PASS;
42 if (skb->protocol == htons(ETH_P_PAE))
43 return RX_HANDLER_PASS;
45 skb_push(skb, ETH_HLEN);
47 skb_forward_csum(skb);
50 return RX_HANDLER_CONSUMED;
53 static int trelay_open(struct inode *inode, struct file *file)
55 file->private_data = inode->i_private;
59 static int trelay_do_remove(struct trelay *tr)
66 netdev_rx_handler_unregister(tr->dev1);
67 netdev_rx_handler_unregister(tr->dev2);
69 debugfs_remove_recursive(tr->debugfs);
75 static struct trelay *trelay_find(struct net_device *dev)
79 list_for_each_entry(tr, &trelay_devs, list) {
80 if (tr->dev1 == dev || tr->dev2 == dev)
86 static int tr_device_event(struct notifier_block *unused, unsigned long event,
89 struct net_device *dev = ptr;
92 if (event != NETDEV_UNREGISTER)
95 tr = trelay_find(dev);
105 static ssize_t trelay_remove_write(struct file *file, const char __user *ubuf,
106 size_t count, loff_t *ppos)
108 struct trelay *tr = file->private_data;
112 ret = trelay_do_remove(tr);
121 static const struct file_operations fops_remove = {
122 .owner = THIS_MODULE,
124 .write = trelay_remove_write,
125 .llseek = default_llseek,
129 static int trelay_do_add(char *name, char *devn1, char *devn2)
131 struct net_device *dev1, *dev2;
132 struct trelay *tr, *tr1;
135 tr = kzalloc(sizeof(*tr) + strlen(name) + 1, GFP_KERNEL);
143 list_for_each_entry(tr1, &trelay_devs, list) {
144 if (!strcmp(tr1->name, name))
149 dev1 = dev_get_by_name_rcu(&init_net, devn1);
150 dev2 = dev_get_by_name_rcu(&init_net, devn2);
154 ret = netdev_rx_handler_register(dev1, trelay_handle_frame, dev2);
158 ret = netdev_rx_handler_register(dev2, trelay_handle_frame, dev1);
160 netdev_rx_handler_unregister(dev1);
167 strcpy(tr->name, name);
170 list_add_tail(&tr->list, &trelay_devs);
172 tr->debugfs = debugfs_create_dir(name, debugfs_dir);
173 debugfs_create_file("remove", S_IWUSR, tr->debugfs, tr, &fops_remove);
185 static ssize_t trelay_add_write(struct file *file, const char __user *ubuf,
186 size_t count, loff_t *ppos)
189 char *dev1, *dev2, *tmp;
192 len = min(count, sizeof(buf) - 1);
193 if (copy_from_user(buf, ubuf, len))
198 if ((tmp = strchr(buf, '\n')))
201 dev1 = strchr(buf, ',');
207 dev2 = strchr(dev1, ',');
212 if (strchr(dev2, ','))
215 if (!strlen(buf) || !strlen(dev1) || !strlen(dev2))
218 ret = trelay_do_add(buf, dev1, dev2);
225 static const struct file_operations fops_add = {
226 .owner = THIS_MODULE,
227 .write = trelay_add_write,
228 .llseek = default_llseek,
231 static struct notifier_block tr_dev_notifier = {
232 .notifier_call = tr_device_event
235 static int __init trelay_init(void)
239 debugfs_dir = debugfs_create_dir("trelay", NULL);
243 debugfs_create_file("add", S_IWUSR, debugfs_dir, NULL, &fops_add);
245 ret = register_netdevice_notifier(&tr_dev_notifier);
252 debugfs_remove_recursive(debugfs_dir);
256 static void __exit trelay_exit(void)
258 struct trelay *tr, *tmp;
260 unregister_netdevice_notifier(&tr_dev_notifier);
263 list_for_each_entry_safe(tr, tmp, &trelay_devs, list)
264 trelay_do_remove(tr);
267 debugfs_remove_recursive(debugfs_dir);
270 module_init(trelay_init);
271 module_exit(trelay_exit);
272 MODULE_LICENSE("GPL");