1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * "LAPB via ethernet" driver release 001
5 * This code REQUIRES 2.1.15 or higher/ NET3.038
7 * This is a "pseudo" network driver to allow LAPB over Ethernet.
9 * This driver can use any ethernet destination address, and can be
10 * limited to accept frames from one dedicated ethernet card only.
13 * LAPBETH 001 Jonathan Naylor Cloned from bpqether.c
14 * 2000-10-29 Henner Eisen lapb_data_indication() return status.
15 * 2000-11-14 Henner Eisen dev_hold/put, NETDEV_GOING_DOWN support
18 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20 #include <linux/errno.h>
21 #include <linux/types.h>
22 #include <linux/socket.h>
24 #include <linux/slab.h>
25 #include <linux/kernel.h>
26 #include <linux/string.h>
27 #include <linux/net.h>
28 #include <linux/inet.h>
29 #include <linux/netdevice.h>
30 #include <linux/if_arp.h>
31 #include <linux/skbuff.h>
33 #include <linux/uaccess.h>
35 #include <linux/interrupt.h>
36 #include <linux/notifier.h>
37 #include <linux/stat.h>
38 #include <linux/module.h>
39 #include <linux/lapb.h>
40 #include <linux/init.h>
42 #include <net/x25device.h>
44 static const u8 bcast_addr[6] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
46 /* If this number is made larger, check that the temporary string buffer
47 * in lapbeth_new_device is large enough to store the probe device name.*/
48 #define MAXLAPBDEV 100
51 struct list_head node;
52 struct net_device *ethdev; /* link to ethernet device */
53 struct net_device *axdev; /* lapbeth device (lapb#) */
56 static LIST_HEAD(lapbeth_devices);
58 /* ------------------------------------------------------------------------ */
61 * Get the LAPB device for the ethernet device
63 static struct lapbethdev *lapbeth_get_x25_dev(struct net_device *dev)
65 struct lapbethdev *lapbeth;
67 list_for_each_entry_rcu(lapbeth, &lapbeth_devices, node, lockdep_rtnl_is_held()) {
68 if (lapbeth->ethdev == dev)
74 static __inline__ int dev_is_ethdev(struct net_device *dev)
76 return dev->type == ARPHRD_ETHER && strncmp(dev->name, "dummy", 5);
79 /* ------------------------------------------------------------------------ */
82 * Receive a LAPB frame via an ethernet interface.
84 static int lapbeth_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype, struct net_device *orig_dev)
87 struct lapbethdev *lapbeth;
89 if (dev_net(dev) != &init_net)
92 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
95 if (!pskb_may_pull(skb, 2))
99 lapbeth = lapbeth_get_x25_dev(dev);
102 if (!netif_running(lapbeth->axdev))
105 len = skb->data[0] + skb->data[1] * 256;
106 dev->stats.rx_packets++;
107 dev->stats.rx_bytes += len;
109 skb_pull(skb, 2); /* Remove the length bytes */
110 skb_trim(skb, len); /* Set the length of the data */
112 if ((err = lapb_data_received(lapbeth->axdev, skb)) != LAPB_OK) {
113 printk(KERN_DEBUG "lapbether: lapb_data_received err - %d\n", err);
127 static int lapbeth_data_indication(struct net_device *dev, struct sk_buff *skb)
137 *ptr = X25_IFACE_DATA;
139 skb->protocol = x25_type_trans(skb, dev);
140 return netif_rx(skb);
144 * Send a LAPB frame via an ethernet interface
146 static netdev_tx_t lapbeth_xmit(struct sk_buff *skb,
147 struct net_device *dev)
152 * Just to be *really* sure not to send anything if the interface
153 * is down, the ethernet device may have gone.
155 if (!netif_running(dev))
158 switch (skb->data[0]) {
161 case X25_IFACE_CONNECT:
162 if ((err = lapb_connect_request(dev)) != LAPB_OK)
163 pr_err("lapb_connect_request error: %d\n", err);
165 case X25_IFACE_DISCONNECT:
166 if ((err = lapb_disconnect_request(dev)) != LAPB_OK)
167 pr_err("lapb_disconnect_request err: %d\n", err);
175 if ((err = lapb_data_request(dev, skb)) != LAPB_OK) {
176 pr_err("lapb_data_request error - %d\n", err);
186 static void lapbeth_data_transmit(struct net_device *ndev, struct sk_buff *skb)
188 struct lapbethdev *lapbeth = netdev_priv(ndev);
190 struct net_device *dev;
193 skb->protocol = htons(ETH_P_X25);
195 ptr = skb_push(skb, 2);
200 ndev->stats.tx_packets++;
201 ndev->stats.tx_bytes += size;
203 skb->dev = dev = lapbeth->ethdev;
205 dev_hard_header(skb, dev, ETH_P_DEC, bcast_addr, NULL, 0);
210 static void lapbeth_connected(struct net_device *dev, int reason)
213 struct sk_buff *skb = dev_alloc_skb(1);
216 pr_err("out of memory\n");
220 ptr = skb_put(skb, 1);
221 *ptr = X25_IFACE_CONNECT;
223 skb->protocol = x25_type_trans(skb, dev);
227 static void lapbeth_disconnected(struct net_device *dev, int reason)
230 struct sk_buff *skb = dev_alloc_skb(1);
233 pr_err("out of memory\n");
237 ptr = skb_put(skb, 1);
238 *ptr = X25_IFACE_DISCONNECT;
240 skb->protocol = x25_type_trans(skb, dev);
247 static int lapbeth_set_mac_address(struct net_device *dev, void *addr)
249 struct sockaddr *sa = addr;
250 memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);
255 static const struct lapb_register_struct lapbeth_callbacks = {
256 .connect_confirmation = lapbeth_connected,
257 .connect_indication = lapbeth_connected,
258 .disconnect_confirmation = lapbeth_disconnected,
259 .disconnect_indication = lapbeth_disconnected,
260 .data_indication = lapbeth_data_indication,
261 .data_transmit = lapbeth_data_transmit,
265 * open/close a device
267 static int lapbeth_open(struct net_device *dev)
271 if ((err = lapb_register(dev, &lapbeth_callbacks)) != LAPB_OK) {
272 pr_err("lapb_register error: %d\n", err);
276 netif_start_queue(dev);
280 static int lapbeth_close(struct net_device *dev)
284 netif_stop_queue(dev);
286 if ((err = lapb_unregister(dev)) != LAPB_OK)
287 pr_err("lapb_unregister error: %d\n", err);
292 /* ------------------------------------------------------------------------ */
294 static const struct net_device_ops lapbeth_netdev_ops = {
295 .ndo_open = lapbeth_open,
296 .ndo_stop = lapbeth_close,
297 .ndo_start_xmit = lapbeth_xmit,
298 .ndo_set_mac_address = lapbeth_set_mac_address,
301 static void lapbeth_setup(struct net_device *dev)
303 dev->netdev_ops = &lapbeth_netdev_ops;
304 dev->needs_free_netdev = true;
305 dev->type = ARPHRD_X25;
311 * Setup a new device.
313 static int lapbeth_new_device(struct net_device *dev)
315 struct net_device *ndev;
316 struct lapbethdev *lapbeth;
321 ndev = alloc_netdev(sizeof(*lapbeth), "lapb%d", NET_NAME_UNKNOWN,
326 /* When transmitting data:
327 * first this driver removes a pseudo header of 1 byte,
328 * then the lapb module prepends an LAPB header of at most 3 bytes,
329 * then this driver prepends a length field of 2 bytes,
330 * then the underlying Ethernet device prepends its own header.
332 ndev->hard_header_len = -1 + 3 + 2 + dev->hard_header_len;
334 lapbeth = netdev_priv(ndev);
335 lapbeth->axdev = ndev;
338 lapbeth->ethdev = dev;
341 if (register_netdevice(ndev))
344 list_add_rcu(&lapbeth->node, &lapbeth_devices);
355 * Free a lapb network device.
357 static void lapbeth_free_device(struct lapbethdev *lapbeth)
359 dev_put(lapbeth->ethdev);
360 list_del_rcu(&lapbeth->node);
361 unregister_netdevice(lapbeth->axdev);
365 * Handle device status changes.
367 * Called from notifier with RTNL held.
369 static int lapbeth_device_event(struct notifier_block *this,
370 unsigned long event, void *ptr)
372 struct lapbethdev *lapbeth;
373 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
375 if (dev_net(dev) != &init_net)
378 if (!dev_is_ethdev(dev))
383 /* New ethernet device -> new LAPB interface */
384 if (lapbeth_get_x25_dev(dev) == NULL)
385 lapbeth_new_device(dev);
388 /* ethernet device closed -> close LAPB interface */
389 lapbeth = lapbeth_get_x25_dev(dev);
391 dev_close(lapbeth->axdev);
393 case NETDEV_UNREGISTER:
394 /* ethernet device disappears -> remove LAPB interface */
395 lapbeth = lapbeth_get_x25_dev(dev);
397 lapbeth_free_device(lapbeth);
404 /* ------------------------------------------------------------------------ */
406 static struct packet_type lapbeth_packet_type __read_mostly = {
407 .type = cpu_to_be16(ETH_P_DEC),
411 static struct notifier_block lapbeth_dev_notifier = {
412 .notifier_call = lapbeth_device_event,
415 static const char banner[] __initconst =
416 KERN_INFO "LAPB Ethernet driver version 0.02\n";
418 static int __init lapbeth_init_driver(void)
420 dev_add_pack(&lapbeth_packet_type);
422 register_netdevice_notifier(&lapbeth_dev_notifier);
428 module_init(lapbeth_init_driver);
430 static void __exit lapbeth_cleanup_driver(void)
432 struct lapbethdev *lapbeth;
433 struct list_head *entry, *tmp;
435 dev_remove_pack(&lapbeth_packet_type);
436 unregister_netdevice_notifier(&lapbeth_dev_notifier);
439 list_for_each_safe(entry, tmp, &lapbeth_devices) {
440 lapbeth = list_entry(entry, struct lapbethdev, node);
442 dev_put(lapbeth->ethdev);
443 unregister_netdevice(lapbeth->axdev);
447 module_exit(lapbeth_cleanup_driver);
449 MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>");
450 MODULE_DESCRIPTION("The unofficial LAPB over Ethernet driver");
451 MODULE_LICENSE("GPL");