--- /dev/null
+/*
+ * trelay.c: Trivial Ethernet Relay
+ *
+ * Copyright (C) 2012 Felix Fietkau <nbd@openwrt.org>
+ *
+ * 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");
projects / openwrt / openwrt.git / blobdiff