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/*
* "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/segment.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/notifier.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>
#include <linux/netfilter.h>
#include <linux/module.h>
#include <linux/lapb.h>
#include <linux/init.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
static struct lapbethdev {
struct lapbethdev *next;
char ethname[14]; /* ether device name */
struct net_device *ethdev; /* link to ethernet device */
struct net_device axdev; /* lapbeth device (lapb#) */
struct net_device_stats stats; /* some statistics */
} *lapbeth_devices /* = NULL initially */;
/* ------------------------------------------------------------------------ */
/*
* Get the LAPB device for the ethernet device
*/
static inline struct net_device *lapbeth_get_x25_dev(struct net_device *dev)
{
struct lapbethdev *lapbeth;
for (lapbeth = lapbeth_devices; lapbeth != NULL; lapbeth = lapbeth->next)
if (lapbeth->ethdev == dev)
return &lapbeth->axdev;
return NULL;
}
static inline int dev_is_ethdev(struct net_device *dev)
{
return (
dev->type == ARPHRD_ETHER
&& strncmp(dev->name, "dummy", 5)
);
}
/*
* Sanity check: remove all devices that ceased to exists and
* return '1' if the given LAPB device was affected.
*/
static int lapbeth_check_devices(struct net_device *dev)
{
struct lapbethdev *lapbeth, *lapbeth_prev, *lapbeth_next;
int result = 0;
unsigned long flags;
save_flags(flags);
cli();
lapbeth_prev = NULL;
for (lapbeth = lapbeth_devices; lapbeth != NULL; lapbeth = lapbeth_next) {
lapbeth_next = lapbeth->next;
if (!dev_get(lapbeth->ethname)) {
if (lapbeth_prev)
lapbeth_prev->next = lapbeth->next;
else
lapbeth_devices = lapbeth->next;
if (&lapbeth->axdev == dev)
result = 1;
unregister_netdev(&lapbeth->axdev);
dev_put(lapbeth->ethdev);
kfree(lapbeth);
}
else
lapbeth_prev = lapbeth;
}
restore_flags(flags);
return result;
}
/* ------------------------------------------------------------------------ */
/*
* Receive a LAPB frame via an ethernet interface.
*/
static int lapbeth_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype)
{
int len, err;
struct lapbethdev *lapbeth;
skb->sk = NULL; /* Initially we don't know who it's for */
dev = lapbeth_get_x25_dev(dev);
if (dev == NULL || !netif_running(dev)) {
kfree_skb(skb);
return 0;
}
lapbeth = (struct lapbethdev *) dev->priv;
lapbeth->stats.rx_packets++;
len = skb->data[0] + skb->data[1] * 256;
skb_pull(skb, 2); /* Remove the length bytes */
skb_trim(skb, len); /* Set the length of the data */
if ((err = lapb_data_received(lapbeth, skb)) != LAPB_OK) {
kfree_skb(skb);
printk(KERN_DEBUG "lapbether: lapb_data_received err - %d\n", err);
}
return 0;
}
static int lapbeth_data_indication(void *token, struct sk_buff *skb)
{
struct lapbethdev *lapbeth = (struct lapbethdev *) token;
unsigned char *ptr;
ptr = skb_push(skb, 1);
*ptr = 0x00;
skb->dev = &lapbeth->axdev;
skb->protocol = htons(ETH_P_X25);
skb->mac.raw = skb->data;
skb->pkt_type = PACKET_HOST;
return netif_rx(skb);
}
/*
* Send a LAPB frame via an ethernet interface
*/
static int lapbeth_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct lapbethdev *lapbeth = (struct lapbethdev *) dev->priv;
int err;
/*
* Just to be *really* sure not to send anything if the interface
* is down, the ethernet device may have gone.
*/
if (!netif_running(dev)) {
lapbeth_check_devices(dev);
kfree_skb(skb);
return -ENODEV;
}
switch (skb->data[0]) {
case 0x00:
break;
case 0x01:
if ((err = lapb_connect_request(lapbeth)) != LAPB_OK)
printk(KERN_ERR "lapbeth: lapb_connect_request error - %d\n", err);
kfree_skb(skb);
return 0;
case 0x02:
if ((err = lapb_disconnect_request(lapbeth)) != LAPB_OK)
printk(KERN_ERR "lapbeth: lapb_disconnect_request err - %d\n", err);
kfree_skb(skb);
return 0;
default:
kfree_skb(skb);
return 0;
}
skb_pull(skb, 1);
if ((err = lapb_data_request(lapbeth, skb)) != LAPB_OK) {
printk(KERN_ERR "lapbeth: lapb_data_request error - %d\n", err);
kfree_skb(skb);
return -ENOMEM;
}
return 0;
}
static void lapbeth_data_transmit(void *token, struct sk_buff *skb)
{
struct lapbethdev *lapbeth = (struct lapbethdev *) token;
unsigned char *ptr;
struct net_device *dev;
int size;
skb->protocol = htons(ETH_P_X25);
size = skb->len;
ptr = skb_push(skb, 2);
*ptr++ = size % 256;
*ptr++ = size / 256;
lapbeth->stats.tx_packets++;
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(void *token, int reason)
{
struct lapbethdev *lapbeth = (struct lapbethdev *) token;
struct sk_buff *skb;
unsigned char *ptr;
if ((skb = dev_alloc_skb(1)) == NULL) {
printk(KERN_ERR "lapbeth: out of memory\n");
return;
}
ptr = skb_put(skb, 1);
*ptr = 0x01;
skb->dev = &lapbeth->axdev;
skb->protocol = htons(ETH_P_X25);
skb->mac.raw = skb->data;
skb->pkt_type = PACKET_HOST;
netif_rx(skb);
}
static void lapbeth_disconnected(void *token, int reason)
{
struct lapbethdev *lapbeth = (struct lapbethdev *) token;
struct sk_buff *skb;
unsigned char *ptr;
if ((skb = dev_alloc_skb(1)) == NULL) {
printk(KERN_ERR "lapbeth: out of memory\n");
return;
}
ptr = skb_put(skb, 1);
*ptr = 0x02;
skb->dev = &lapbeth->axdev;
skb->protocol = htons(ETH_P_X25);
skb->mac.raw = skb->data;
skb->pkt_type = PACKET_HOST;
netif_rx(skb);
}
/*
* Statistics
*/
static struct net_device_stats *lapbeth_get_stats(struct net_device *dev)
{
struct lapbethdev *lapbeth = (struct lapbethdev *) dev->priv;
return &lapbeth->stats;
}
/*
* Set AX.25 callsign
*/
static int lapbeth_set_mac_address(struct net_device *dev, void *addr)
{
struct sockaddr *sa = (struct sockaddr *) addr;
memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);
return 0;
}
/*
* open/close a device
*/
static int lapbeth_open(struct net_device *dev)
{
struct lapb_register_struct lapbeth_callbacks;
struct lapbethdev *lapbeth;
int err;
if (lapbeth_check_devices(dev))
return -ENODEV; /* oops, it's gone */
lapbeth = (struct lapbethdev *) dev->priv;
lapbeth_callbacks.connect_confirmation = lapbeth_connected;
lapbeth_callbacks.connect_indication = lapbeth_connected;
lapbeth_callbacks.disconnect_confirmation = lapbeth_disconnected;
lapbeth_callbacks.disconnect_indication = lapbeth_disconnected;
lapbeth_callbacks.data_indication = lapbeth_data_indication;
lapbeth_callbacks.data_transmit = lapbeth_data_transmit;
if ((err = lapb_register(lapbeth, &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)
{
struct lapbethdev *lapbeth = (struct lapbethdev *) dev->priv;
int err;
netif_stop_queue(dev);
if ((err = lapb_unregister(lapbeth)) != LAPB_OK)
printk(KERN_ERR "lapbeth: lapb_unregister error - %d\n", err);
return 0;
}
/* ------------------------------------------------------------------------ */
/*
* Setup a new device.
*/
static int lapbeth_new_device(struct net_device *dev)
{
int k;
unsigned char buf[14];
struct lapbethdev *lapbeth, *lapbeth2;
if ((lapbeth = kmalloc(sizeof(struct lapbethdev), GFP_KERNEL)) == NULL)
return -ENOMEM;
memset(lapbeth, 0, sizeof(struct lapbethdev));
dev_hold(dev);
lapbeth->ethdev = dev;
lapbeth->ethname[sizeof(lapbeth->ethname)-1] = '\0';
strncpy(lapbeth->ethname, dev->name, sizeof(lapbeth->ethname)-1);
dev = &lapbeth->axdev;
SET_MODULE_OWNER(dev);
for (k = 0; k < MAXLAPBDEV; k++) {
struct net_device *odev;
sprintf(buf, "lapb%d", k);
if ((odev = __dev_get_by_name(buf)) == NULL || lapbeth_check_devices(odev))
break;
}
if (k == MAXLAPBDEV) {
dev_put(dev);
kfree(lapbeth);
return -ENODEV;
}
dev->priv = (void *)lapbeth; /* pointer back */
strcpy(dev->name, buf);
if (register_netdev(dev) != 0) {
dev_put(dev);
kfree(lapbeth);
return -EIO;
}
dev->hard_start_xmit = lapbeth_xmit;
dev->open = lapbeth_open;
dev->stop = lapbeth_close;
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;
cli();
if (lapbeth_devices == NULL) {
lapbeth_devices = lapbeth;
} else {
for (lapbeth2 = lapbeth_devices; lapbeth2->next != NULL; lapbeth2 = lapbeth2->next);
lapbeth2->next = lapbeth;
}
sti();
return 0;
}
/*
* Handle device status changes.
*/
static int lapbeth_device_event(struct notifier_block *this, unsigned long event, void *ptr)
{
struct net_device *dev = (struct net_device *) ptr;
if (!dev_is_ethdev(dev))
return NOTIFY_DONE;
lapbeth_check_devices(NULL);
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_GOING_DOWN:
case NETDEV_DOWN: /* ethernet device closed -> close LAPB interface */
if ((dev = lapbeth_get_x25_dev(dev)) != NULL)
dev_close(dev);
break;
default:
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 0.01\n";
static int __init lapbeth_init_driver(void)
{
struct net_device *dev;
dev_add_pack(&lapbeth_packet_type);
register_netdevice_notifier(&lapbeth_dev_notifier);
printk(banner);
read_lock_bh(&dev_base_lock);
for (dev = dev_base; dev != NULL; dev = dev->next) {
if (dev_is_ethdev(dev)) {
read_unlock_bh(&dev_base_lock);
lapbeth_new_device(dev);
read_lock_bh(&dev_base_lock);
}
}
read_unlock_bh(&dev_base_lock);
return 0;
}
module_init(lapbeth_init_driver);
static void __exit lapbeth_cleanup_driver(void)
{
struct lapbethdev *lapbeth;
dev_remove_pack(&lapbeth_packet_type);
unregister_netdevice_notifier(&lapbeth_dev_notifier);
for (lapbeth = lapbeth_devices; lapbeth != NULL; lapbeth = lapbeth->next)
unregister_netdev(&lapbeth->axdev);
}
module_exit(lapbeth_cleanup_driver);
EXPORT_NO_SYMBOLS;
MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>");
MODULE_DESCRIPTION("The unofficial LAPB over Ethernet driver");
MODULE_LICENSE("GPL");
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