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- /*
- * trelay.c: Trivial Ethernet Relay
- *
- * Copyright (C) 2012 Felix Fietkau <nbd@nbd.name>
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version 2
- * of the License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- */
- #include <linux/module.h>
- #include <linux/list.h>
- #include <linux/mutex.h>
- #include <linux/netdevice.h>
- #include <linux/rtnetlink.h>
- #include <linux/debugfs.h>
- static LIST_HEAD(trelay_devs);
- static struct dentry *debugfs_dir;
- struct trelay {
- struct list_head list;
- struct net_device *dev1, *dev2;
- struct dentry *debugfs;
- char name[];
- };
- rx_handler_result_t trelay_handle_frame(struct sk_buff **pskb)
- {
- struct net_device *dev;
- struct sk_buff *skb = *pskb;
- dev = rcu_dereference(skb->dev->rx_handler_data);
- if (!dev)
- return RX_HANDLER_PASS;
- if (skb->protocol == htons(ETH_P_PAE))
- return RX_HANDLER_PASS;
- skb_push(skb, ETH_HLEN);
- skb->dev = dev;
- skb_forward_csum(skb);
- dev_queue_xmit(skb);
- return RX_HANDLER_CONSUMED;
- }
- static int trelay_open(struct inode *inode, struct file *file)
- {
- file->private_data = inode->i_private;
- return 0;
- }
- static int trelay_do_remove(struct trelay *tr)
- {
- list_del(&tr->list);
- dev_put(tr->dev1);
- dev_put(tr->dev2);
- netdev_rx_handler_unregister(tr->dev1);
- netdev_rx_handler_unregister(tr->dev2);
- debugfs_remove_recursive(tr->debugfs);
- kfree(tr);
- return 0;
- }
- static struct trelay *trelay_find(struct net_device *dev)
- {
- struct trelay *tr;
- list_for_each_entry(tr, &trelay_devs, list) {
- if (tr->dev1 == dev || tr->dev2 == dev)
- return tr;
- }
- return NULL;
- }
- static int tr_device_event(struct notifier_block *unused, unsigned long event,
- void *ptr)
- {
- struct net_device *dev = ptr;
- struct trelay *tr;
- if (event != NETDEV_UNREGISTER)
- goto out;
- tr = trelay_find(dev);
- if (!tr)
- goto out;
- trelay_do_remove(tr);
- out:
- return NOTIFY_DONE;
- }
- static ssize_t trelay_remove_write(struct file *file, const char __user *ubuf,
- size_t count, loff_t *ppos)
- {
- struct trelay *tr = file->private_data;
- int ret;
- rtnl_lock();
- ret = trelay_do_remove(tr);
- rtnl_unlock();
- if (ret < 0)
- return ret;
- return count;
- }
- static const struct file_operations fops_remove = {
- .owner = THIS_MODULE,
- .open = trelay_open,
- .write = trelay_remove_write,
- .llseek = default_llseek,
- };
- static int trelay_do_add(char *name, char *devn1, char *devn2)
- {
- struct net_device *dev1, *dev2;
- struct trelay *tr, *tr1;
- int ret;
- tr = kzalloc(sizeof(*tr) + strlen(name) + 1, GFP_KERNEL);
- if (!tr)
- return -ENOMEM;
- rtnl_lock();
- rcu_read_lock();
- ret = -EEXIST;
- list_for_each_entry(tr1, &trelay_devs, list) {
- if (!strcmp(tr1->name, name))
- goto out;
- }
- ret = -ENOENT;
- dev1 = dev_get_by_name_rcu(&init_net, devn1);
- dev2 = dev_get_by_name_rcu(&init_net, devn2);
- if (!dev1 || !dev2)
- goto out;
- ret = netdev_rx_handler_register(dev1, trelay_handle_frame, dev2);
- if (ret < 0)
- goto out;
- ret = netdev_rx_handler_register(dev2, trelay_handle_frame, dev1);
- if (ret < 0) {
- netdev_rx_handler_unregister(dev1);
- goto out;
- }
- dev_hold(dev1);
- dev_hold(dev2);
- strcpy(tr->name, name);
- tr->dev1 = dev1;
- tr->dev2 = dev2;
- list_add_tail(&tr->list, &trelay_devs);
- tr->debugfs = debugfs_create_dir(name, debugfs_dir);
- debugfs_create_file("remove", S_IWUSR, tr->debugfs, tr, &fops_remove);
- ret = 0;
- out:
- rcu_read_unlock();
- rtnl_unlock();
- if (ret < 0)
- kfree(tr);
- return ret;
- }
- static ssize_t trelay_add_write(struct file *file, const char __user *ubuf,
- size_t count, loff_t *ppos)
- {
- char buf[256];
- char *dev1, *dev2, *tmp;
- ssize_t len, ret;
- len = min(count, sizeof(buf) - 1);
- if (copy_from_user(buf, ubuf, len))
- return -EFAULT;
- buf[len] = 0;
- if ((tmp = strchr(buf, '\n')))
- *tmp = 0;
- dev1 = strchr(buf, ',');
- if (!dev1)
- return -EINVAL;
- *(dev1++) = 0;
- dev2 = strchr(dev1, ',');
- if (!dev2)
- return -EINVAL;
- *(dev2++) = 0;
- if (strchr(dev2, ','))
- return -EINVAL;
- if (!strlen(buf) || !strlen(dev1) || !strlen(dev2))
- return -EINVAL;
- ret = trelay_do_add(buf, dev1, dev2);
- if (ret < 0)
- return ret;
- return count;
- }
- static const struct file_operations fops_add = {
- .owner = THIS_MODULE,
- .write = trelay_add_write,
- .llseek = default_llseek,
- };
- static struct notifier_block tr_dev_notifier = {
- .notifier_call = tr_device_event
- };
- static int __init trelay_init(void)
- {
- int ret;
- debugfs_dir = debugfs_create_dir("trelay", NULL);
- if (!debugfs_dir)
- return -ENOMEM;
- debugfs_create_file("add", S_IWUSR, debugfs_dir, NULL, &fops_add);
- ret = register_netdevice_notifier(&tr_dev_notifier);
- if (ret < 0)
- goto error;
- return 0;
- error:
- debugfs_remove_recursive(debugfs_dir);
- return ret;
- }
- static void __exit trelay_exit(void)
- {
- struct trelay *tr, *tmp;
- unregister_netdevice_notifier(&tr_dev_notifier);
- rtnl_lock();
- list_for_each_entry_safe(tr, tmp, &trelay_devs, list)
- trelay_do_remove(tr);
- rtnl_unlock();
- debugfs_remove_recursive(debugfs_dir);
- }
- module_init(trelay_init);
- module_exit(trelay_exit);
- MODULE_LICENSE("GPL");
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