/*
* "LAPB via ethernet" driver release 001
*
* This code REQUIRES 2.1.15 or higher/ NET3.038
*
* This module:
* This module 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 is a "pseudo" network driver to allow LAPB over Ethernet.
*
* This driver can use any ethernet destination address, and can be
* limited to accept frames from one dedicated ethernet card only.
*
* History
* LAPBETH 001 Jonathan Naylor Cloned from bpqether.c
* 2000-10-29 Henner Eisen lapb_data_indication() return status.
* 2000-11-14 Henner Eisen dev_hold/put, NETDEV_GOING_DOWN support
*/
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/net.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/notifier.h>
#include <linux/stat.h>
#include <linux/netfilter.h>
#include <linux/module.h>
#include <linux/lapb.h>
#include <linux/init.h>
#include <net/x25device.h>
static char bcast_addr[6] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
/* If this number is made larger, check that the temporary string buffer
* in lapbeth_new_device is large enough to store the probe device name.*/
#define MAXLAPBDEV 100
struct lapbethdev {
struct list_head node;
struct net_device *ethdev; /* link to ethernet device */
struct net_device *axdev; /* lapbeth device (lapb#) */
struct net_device_stats stats; /* some statistics */
};
static struct list_head lapbeth_devices = LIST_HEAD_INIT(lapbeth_devices);
/* ------------------------------------------------------------------------ */
/*
* Get the LAPB device for the ethernet device
*/
static struct lapbethdev *lapbeth_get_x25_dev(struct net_device *dev)
{
struct lapbethdev *lapbeth;
list_for_each_entry_rcu(lapbeth, &lapbeth_devices, node) {
if (lapbeth->ethdev == dev)
return lapbeth;
}
return NULL;
}
static __inline__ int dev_is_ethdev(struct net_device *dev)
{
return dev->type == ARPHRD_ETHER && strncmp(dev->name, "dummy", 5);
}
/* ------------------------------------------------------------------------ */
/*
* Receive a LAPB frame via an ethernet interface.
*/
static int lapbeth_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype, struct net_device *orig_dev)
{
int len, err;
struct lapbethdev *lapbeth;
if (dev->nd_net != &init_net)
goto drop;
if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
return NET_RX_DROP;
if (!pskb_may_pull(skb, 2))
goto drop;
rcu_read_lock();
lapbeth = lapbeth_get_x25_dev(dev);
if (!lapbeth)
goto drop_unlock;
if (!netif_running(lapbeth->axdev))
goto drop_unlock;
lapbeth->stats.rx_packets++;
len = skb->data[0] + skb->data[1] * 256;
lapbeth->stats.rx_bytes += len;
skb_pull(skb, 2); /* Remove the length bytes */
skb_trim(skb, len); /* Set the length of the data */
if ((err = lapb_data_received(lapbeth->axdev, skb)) != LAPB_OK) {
printk(KERN_DEBUG "lapbether: lapb_data_received err - %d\n", err);
goto drop_unlock;
}
out:
rcu_read_unlock();
return 0;
drop_unlock:
kfree_skb(skb);
goto out;
drop:
kfree_skb(skb);
return 0;
}
static int lapbeth_data_indication(struct net_device *dev, struct sk_buff *skb)
{
unsigned char *ptr;
skb_push(skb, 1);
if (skb_cow(skb, 1))
return NET_RX_DROP;
ptr = skb->data;
*ptr = 0x00;
skb->protocol = x25_type_trans(skb, dev);
skb->dev->last_rx = jiffies;
return netif_rx(skb);
}
/*
* Send a LAPB frame via an ethernet interface
*/
static int lapbeth_xmit(struct sk_buff *skb, struct net_device *dev)
{
int err = -ENODEV;
/*
* Just to be *really* sure not to send anything if the interface
* is down, the ethernet device may have gone.
*/
if (!netif_running(dev)) {
goto drop;
}
switch (skb->data[0]) {
case 0x00:
err = 0;
break;
case 0x01:
if ((err = lapb_connect_request(dev)) != LAPB_OK)
printk(KERN_ERR "lapbeth: lapb_connect_request "
"error: %d\n", err);
goto drop_ok;
case 0x02:
if ((err = lapb_disconnect_request(dev)) != LAPB_OK)
printk(KERN_ERR "lapbeth: lapb_disconnect_request "
"err: %d\n", err);
/* Fall thru */
default:
goto drop_ok;
}
skb_pull(skb, 1);
if ((err = lapb_data_request(dev, skb)) != LAPB_OK) {
printk(KERN_ERR "lapbeth: lapb_data_request error - %d\n", err);
err = -ENOMEM;
goto drop;
}
err = 0;
out:
return err;
drop_ok:
err = 0;
drop:
kfree_skb(skb);
goto out;
}
static void lapbeth_data_transmit(struct net_device *ndev, struct sk_buff *skb)
{
struct lapbethdev *lapbeth = netdev_priv(ndev);
unsigned char *ptr;
struct net_device *dev;
int size = skb->len;
skb->protocol = htons(ETH_P_X25);
ptr = skb_push(skb, 2);
*ptr++ = size % 256;
*ptr++ = size / 256;
lapbeth->stats.tx_packets++;
lapbeth->stats.tx_bytes += size;
skb->dev = dev = lapbeth->ethdev;
dev_hard_header(skb, dev, ETH_P_DEC, bcast_addr, NULL, 0);
dev_queue_xmit(skb);
}
static void lapbeth_connected(struct net_device *dev, int reason)
{
unsigned char *ptr;
struct sk_buff *skb = dev_alloc_skb(1);
if (!skb) {
printk(KERN_ERR "lapbeth: out of memory\n");
return;
}
ptr = skb_put(skb, 1);
*ptr = 0x01;
skb->protocol = x25_type_trans(skb, dev);
skb->dev->last_rx = jiffies;
netif_rx(skb);
}
static void lapbeth_disconnected(struct net_device *dev, int reason)
{
unsigned char *ptr;
struct sk_buff *skb = dev_alloc_skb(1);
if (!skb) {
printk(KERN_ERR "lapbeth: out of memory\n");
return;
}
ptr = skb_put(skb, 1);
*ptr = 0x02;
skb->protocol = x25_type_trans(skb, dev);
skb->dev->last_rx = jiffies;
netif_rx(skb);
}
/*
* Statistics
*/
static struct net_device_stats *lapbeth_get_stats(struct net_device *dev)
{
struct lapbethdev *lapbeth = netdev_priv(dev);
return &lapbeth->stats;
}
/*
* Set AX.25 callsign
*/
static int lapbeth_set_mac_address(struct net_device *dev, void *addr)
{
struct sockaddr *sa = addr;
memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);
return 0;
}
static struct lapb_register_struct lapbeth_callbacks = {
.connect_confirmation = lapbeth_connected,
.connect_indication = lapbeth_connected,
.disconnect_confirmation = lapbeth_disconnected,
.disconnect_indication = lapbeth_disconnected,
.data_indication = lapbeth_data_indication,
.data_transmit = lapbeth_data_transmit,
};
/*
* open/close a device
*/
static int lapbeth_open(struct net_device *dev)
{
int err;
if ((err = lapb_register(dev, &lapbeth_callbacks)) != LAPB_OK) {
printk(KERN_ERR "lapbeth: lapb_register error - %d\n", err);
return -ENODEV;
}
netif_start_queue(dev);
return 0;
}
static int lapbeth_close(struct net_device *dev)
{
int err;
netif_stop_queue(dev);
if ((err = lapb_unregister(dev)) != LAPB_OK)
printk(KERN_ERR "lapbeth: lapb_unregister error - %d\n", err);
return 0;
}
/* ------------------------------------------------------------------------ */
static void lapbeth_setup(struct net_device *dev)
{
dev->hard_start_xmit = lapbeth_xmit;
dev->open = lapbeth_open;
dev->stop = lapbeth_close;
dev->destructor = free_netdev;
dev->set_mac_address = lapbeth_set_mac_address;
dev->get_stats = lapbeth_get_stats;
dev->type = ARPHRD_X25;
dev->hard_header_len = 3;
dev->mtu = 1000;
dev->addr_len = 0;
}
/*
* Setup a new device.
*/
static int lapbeth_new_device(struct net_device *dev)
{
struct net_device *ndev;
struct lapbethdev *lapbeth;
int rc = -ENOMEM;
ASSERT_RTNL();
ndev = alloc_netdev(sizeof(*lapbeth), "lapb%d",
lapbeth_setup);
if (!ndev)
goto out;
lapbeth = netdev_priv(ndev);
lapbeth->axdev = ndev;
dev_hold(dev);
lapbeth->ethdev = dev;
rc = dev_alloc_name(ndev, ndev->name);
if (rc < 0)
goto fail;
rc = -EIO;
if (register_netdevice(ndev))
goto fail;
list_add_rcu(&lapbeth->node, &lapbeth_devices);
rc = 0;
out:
return rc;
fail:
dev_put(dev);
free_netdev(ndev);
kfree(lapbeth);
goto out;
}
/*
* Free a lapb network device.
*/
static void lapbeth_free_device(struct lapbethdev *lapbeth)
{
dev_put(lapbeth->ethdev);
list_del_rcu(&lapbeth->node);
unregister_netdevice(lapbeth->axdev);
}
/*
* Handle device status changes.
*
* Called from notifier with RTNL held.
*/
static int lapbeth_device_event(struct notifier_block *this,
unsigned long event, void *ptr)
{
struct lapbethdev *lapbeth;
struct net_device *dev = ptr;
if (dev->nd_net != &init_net)
return NOTIFY_DONE;
if (!dev_is_ethdev(dev))
return NOTIFY_DONE;
switch (event) {
case NETDEV_UP:
/* New ethernet device -> new LAPB interface */
if (lapbeth_get_x25_dev(dev) == NULL)
lapbeth_new_device(dev);
break;
case NETDEV_DOWN:
/* ethernet device closed -> close LAPB interface */
lapbeth = lapbeth_get_x25_dev(dev);
if (lapbeth)
dev_close(lapbeth->axdev);
break;
case NETDEV_UNREGISTER:
/* ethernet device disappears -> remove LAPB interface */
lapbeth = lapbeth_get_x25_dev(dev);
if (lapbeth)
lapbeth_free_device(lapbeth);
break;
}
return NOTIFY_DONE;
}
/* ------------------------------------------------------------------------ */
static struct packet_type lapbeth_packet_type = {
.type = __constant_htons(ETH_P_DEC),
.func = lapbeth_rcv,
};
static struct notifier_block lapbeth_dev_notifier = {
.notifier_call = lapbeth_device_event,
};
static char banner[] __initdata = KERN_INFO "LAPB Ethernet driver version 0.02\n";
static int __init lapbeth_init_driver(void)
{
dev_add_pack(&lapbeth_packet_type);
register_netdevice_notifier(&lapbeth_dev_notifier);
printk(banner);
return 0;
}
module_init(lapbeth_init_driver);
static void __exit lapbeth_cleanup_driver(void)
{
struct lapbethdev *lapbeth;
struct list_head *entry, *tmp;
dev_remove_pack(&lapbeth_packet_type);
unregister_netdevice_notifier(&lapbeth_dev_notifier);
rtnl_lock();
list_for_each_safe(entry, tmp, &lapbeth_devices) {
lapbeth = list_entry(entry, struct lapbethdev, node);
unregister_netdevice(lapbeth->axdev);
}
rtnl_unlock();
}
module_exit(lapbeth_cleanup_driver);
MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>");
MODULE_DESCRIPTION("The unofficial LAPB over Ethernet driver");
MODULE_LICENSE("GPL");
