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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * G8BPQ compatible "AX.25 via ethernet" driver release 004
4 *
5 * This code REQUIRES 2.0.0 or higher/ NET3.029
6 *
7 * This is a "pseudo" network driver to allow AX.25 over Ethernet
8 * using G8BPQ encapsulation. It has been extracted from the protocol
9 * implementation because
10 *
11 * - things got unreadable within the protocol stack
12 * - to cure the protocol stack from "feature-ism"
13 * - a protocol implementation shouldn't need to know on
14 * which hardware it is running
15 * - user-level programs like the AX.25 utilities shouldn't
16 * need to know about the hardware.
17 * - IP over ethernet encapsulated AX.25 was impossible
18 * - rxecho.c did not work
19 * - to have room for extensions
20 * - it just deserves to "live" as an own driver
21 *
22 * This driver can use any ethernet destination address, and can be
23 * limited to accept frames from one dedicated ethernet card only.
24 *
25 * Note that the driver sets up the BPQ devices automagically on
26 * startup or (if started before the "insmod" of an ethernet device)
27 * on "ifconfig up". It hopefully will remove the BPQ on "rmmod"ing
28 * the ethernet device (in fact: as soon as another ethernet or bpq
29 * device gets "ifconfig"ured).
30 *
31 * I have heard that several people are thinking of experiments
32 * with highspeed packet radio using existing ethernet cards.
33 * Well, this driver is prepared for this purpose, just add
34 * your tx key control and a txdelay / tailtime algorithm,
35 * probably some buffering, and /voila/...
36 *
37 * History
38 * BPQ 001 Joerg(DL1BKE) Extracted BPQ code from AX.25
39 * protocol stack and added my own
40 * yet existing patches
41 * BPQ 002 Joerg(DL1BKE) Scan network device list on
42 * startup.
43 * BPQ 003 Joerg(DL1BKE) Ethernet destination address
44 * and accepted source address
45 * can be configured by an ioctl()
46 * call.
47 * Fixed to match Linux networking
48 * changes - 2.1.15.
49 * BPQ 004 Joerg(DL1BKE) Fixed to not lock up on ifconfig.
50 */
51
52#include <linux/errno.h>
53#include <linux/types.h>
54#include <linux/socket.h>
55#include <linux/in.h>
56#include <linux/kernel.h>
57#include <linux/string.h>
58#include <linux/net.h>
59#include <linux/slab.h>
60#include <net/ax25.h>
61#include <linux/inet.h>
62#include <linux/netdevice.h>
63#include <linux/etherdevice.h>
64#include <linux/if_arp.h>
65#include <linux/skbuff.h>
66#include <net/sock.h>
67#include <linux/uaccess.h>
68#include <linux/mm.h>
69#include <linux/interrupt.h>
70#include <linux/notifier.h>
71#include <linux/proc_fs.h>
72#include <linux/seq_file.h>
73#include <linux/stat.h>
74#include <linux/module.h>
75#include <linux/init.h>
76#include <linux/rtnetlink.h>
77
78#include <net/ip.h>
79#include <net/arp.h>
80#include <net/net_namespace.h>
81
82#include <linux/bpqether.h>
83
84static const char banner[] __initconst = KERN_INFO \
85 "AX.25: bpqether driver version 004\n";
86
87static int bpq_rcv(struct sk_buff *, struct net_device *, struct packet_type *, struct net_device *);
88static int bpq_device_event(struct notifier_block *, unsigned long, void *);
89
90static struct packet_type bpq_packet_type __read_mostly = {
91 .type = cpu_to_be16(ETH_P_BPQ),
92 .func = bpq_rcv,
93};
94
95static struct notifier_block bpq_dev_notifier = {
96 .notifier_call = bpq_device_event,
97};
98
99
100struct bpqdev {
101 struct list_head bpq_list; /* list of bpq devices chain */
102 struct net_device *ethdev; /* link to ethernet device */
103 struct net_device *axdev; /* bpq device (bpq#) */
104 char dest_addr[6]; /* ether destination address */
105 char acpt_addr[6]; /* accept ether frames from this address only */
106};
107
108static LIST_HEAD(bpq_devices);
109
110/*
111 * bpqether network devices are paired with ethernet devices below them, so
112 * form a special "super class" of normal ethernet devices; split their locks
113 * off into a separate class since they always nest.
114 */
115static struct lock_class_key bpq_netdev_xmit_lock_key;
116static struct lock_class_key bpq_netdev_addr_lock_key;
117
118static void bpq_set_lockdep_class_one(struct net_device *dev,
119 struct netdev_queue *txq,
120 void *_unused)
121{
122 lockdep_set_class(&txq->_xmit_lock, &bpq_netdev_xmit_lock_key);
123}
124
125static void bpq_set_lockdep_class(struct net_device *dev)
126{
127 lockdep_set_class(&dev->addr_list_lock, &bpq_netdev_addr_lock_key);
128 netdev_for_each_tx_queue(dev, bpq_set_lockdep_class_one, NULL);
129}
130
131/* ------------------------------------------------------------------------ */
132
133
134/*
135 * Get the ethernet device for a BPQ device
136 */
137static inline struct net_device *bpq_get_ether_dev(struct net_device *dev)
138{
139 struct bpqdev *bpq = netdev_priv(dev);
140
141 return bpq ? bpq->ethdev : NULL;
142}
143
144/*
145 * Get the BPQ device for the ethernet device
146 */
147static inline struct net_device *bpq_get_ax25_dev(struct net_device *dev)
148{
149 struct bpqdev *bpq;
150
151 list_for_each_entry_rcu(bpq, &bpq_devices, bpq_list,
152 lockdep_rtnl_is_held()) {
153 if (bpq->ethdev == dev)
154 return bpq->axdev;
155 }
156 return NULL;
157}
158
159static inline int dev_is_ethdev(struct net_device *dev)
160{
161 return dev->type == ARPHRD_ETHER && strncmp(dev->name, "dummy", 5);
162}
163
164/* ------------------------------------------------------------------------ */
165
166
167/*
168 * Receive an AX.25 frame via an ethernet interface.
169 */
170static int bpq_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype, struct net_device *orig_dev)
171{
172 int len;
173 char * ptr;
174 struct ethhdr *eth;
175 struct bpqdev *bpq;
176
177 if (!net_eq(dev_net(dev), &init_net))
178 goto drop;
179
180 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
181 return NET_RX_DROP;
182
183 if (!pskb_may_pull(skb, sizeof(struct ethhdr)))
184 goto drop;
185
186 rcu_read_lock();
187 dev = bpq_get_ax25_dev(dev);
188
189 if (dev == NULL || !netif_running(dev))
190 goto drop_unlock;
191
192 /*
193 * if we want to accept frames from just one ethernet device
194 * we check the source address of the sender.
195 */
196
197 bpq = netdev_priv(dev);
198
199 eth = eth_hdr(skb);
200
201 if (!(bpq->acpt_addr[0] & 0x01) &&
202 !ether_addr_equal(eth->h_source, bpq->acpt_addr))
203 goto drop_unlock;
204
205 if (skb_cow(skb, sizeof(struct ethhdr)))
206 goto drop_unlock;
207
208 len = skb->data[0] + skb->data[1] * 256 - 5;
209
210 skb_pull(skb, 2); /* Remove the length bytes */
211 skb_trim(skb, len); /* Set the length of the data */
212
213 dev->stats.rx_packets++;
214 dev->stats.rx_bytes += len;
215
216 ptr = skb_push(skb, 1);
217 *ptr = 0;
218
219 skb->protocol = ax25_type_trans(skb, dev);
220 netif_rx(skb);
221unlock:
222
223 rcu_read_unlock();
224
225 return 0;
226drop_unlock:
227 kfree_skb(skb);
228 goto unlock;
229
230drop:
231 kfree_skb(skb);
232 return 0;
233}
234
235/*
236 * Send an AX.25 frame via an ethernet interface
237 */
238static netdev_tx_t bpq_xmit(struct sk_buff *skb, struct net_device *dev)
239{
240 unsigned char *ptr;
241 struct bpqdev *bpq;
242 struct net_device *orig_dev;
243 int size;
244
245 if (skb->protocol == htons(ETH_P_IP))
246 return ax25_ip_xmit(skb);
247
248 /*
249 * Just to be *really* sure not to send anything if the interface
250 * is down, the ethernet device may have gone.
251 */
252 if (!netif_running(dev)) {
253 kfree_skb(skb);
254 return NETDEV_TX_OK;
255 }
256
257 skb_pull(skb, 1); /* Drop KISS byte */
258 size = skb->len;
259
260 /*
261 * We're about to mess with the skb which may still shared with the
262 * generic networking code so unshare and ensure it's got enough
263 * space for the BPQ headers.
264 */
265 if (skb_cow(skb, AX25_BPQ_HEADER_LEN)) {
266 if (net_ratelimit())
267 pr_err("bpqether: out of memory\n");
268 kfree_skb(skb);
269
270 return NETDEV_TX_OK;
271 }
272
273 ptr = skb_push(skb, 2); /* Make space for length */
274
275 *ptr++ = (size + 5) % 256;
276 *ptr++ = (size + 5) / 256;
277
278 bpq = netdev_priv(dev);
279
280 orig_dev = dev;
281 if ((dev = bpq_get_ether_dev(dev)) == NULL) {
282 orig_dev->stats.tx_dropped++;
283 kfree_skb(skb);
284 return NETDEV_TX_OK;
285 }
286
287 skb->protocol = ax25_type_trans(skb, dev);
288 skb_reset_network_header(skb);
289 dev_hard_header(skb, dev, ETH_P_BPQ, bpq->dest_addr, NULL, 0);
290 dev->stats.tx_packets++;
291 dev->stats.tx_bytes+=skb->len;
292
293 dev_queue_xmit(skb);
294 netif_wake_queue(dev);
295 return NETDEV_TX_OK;
296}
297
298/*
299 * Set AX.25 callsign
300 */
301static int bpq_set_mac_address(struct net_device *dev, void *addr)
302{
303 struct sockaddr *sa = (struct sockaddr *)addr;
304
305 dev_addr_set(dev, sa->sa_data);
306
307 return 0;
308}
309
310/* Ioctl commands
311 *
312 * SIOCSBPQETHOPT reserved for enhancements
313 * SIOCSBPQETHADDR set the destination and accepted
314 * source ethernet address (broadcast
315 * or multicast: accept all)
316 */
317static int bpq_siocdevprivate(struct net_device *dev, struct ifreq *ifr,
318 void __user *data, int cmd)
319{
320 struct bpq_ethaddr __user *ethaddr = data;
321 struct bpqdev *bpq = netdev_priv(dev);
322 struct bpq_req req;
323
324 if (!capable(CAP_NET_ADMIN))
325 return -EPERM;
326
327 switch (cmd) {
328 case SIOCSBPQETHOPT:
329 if (copy_from_user(&req, data, sizeof(struct bpq_req)))
330 return -EFAULT;
331 switch (req.cmd) {
332 case SIOCGBPQETHPARAM:
333 case SIOCSBPQETHPARAM:
334 default:
335 return -EINVAL;
336 }
337
338 break;
339
340 case SIOCSBPQETHADDR:
341 if (copy_from_user(bpq->dest_addr, ethaddr->destination, ETH_ALEN))
342 return -EFAULT;
343 if (copy_from_user(bpq->acpt_addr, ethaddr->accept, ETH_ALEN))
344 return -EFAULT;
345 break;
346
347 default:
348 return -EINVAL;
349 }
350
351 return 0;
352}
353
354/*
355 * open/close a device
356 */
357static int bpq_open(struct net_device *dev)
358{
359 netif_start_queue(dev);
360 return 0;
361}
362
363static int bpq_close(struct net_device *dev)
364{
365 netif_stop_queue(dev);
366 return 0;
367}
368
369
370/* ------------------------------------------------------------------------ */
371
372#ifdef CONFIG_PROC_FS
373/*
374 * Proc filesystem
375 */
376static void *bpq_seq_start(struct seq_file *seq, loff_t *pos)
377 __acquires(RCU)
378{
379 int i = 1;
380 struct bpqdev *bpqdev;
381
382 rcu_read_lock();
383
384 if (*pos == 0)
385 return SEQ_START_TOKEN;
386
387 list_for_each_entry_rcu(bpqdev, &bpq_devices, bpq_list) {
388 if (i == *pos)
389 return bpqdev;
390 }
391 return NULL;
392}
393
394static void *bpq_seq_next(struct seq_file *seq, void *v, loff_t *pos)
395{
396 struct list_head *p;
397 struct bpqdev *bpqdev = v;
398
399 ++*pos;
400
401 if (v == SEQ_START_TOKEN)
402 p = rcu_dereference(list_next_rcu(&bpq_devices));
403 else
404 p = rcu_dereference(list_next_rcu(&bpqdev->bpq_list));
405
406 return (p == &bpq_devices) ? NULL
407 : list_entry(p, struct bpqdev, bpq_list);
408}
409
410static void bpq_seq_stop(struct seq_file *seq, void *v)
411 __releases(RCU)
412{
413 rcu_read_unlock();
414}
415
416
417static int bpq_seq_show(struct seq_file *seq, void *v)
418{
419 if (v == SEQ_START_TOKEN)
420 seq_puts(seq,
421 "dev ether destination accept from\n");
422 else {
423 const struct bpqdev *bpqdev = v;
424
425 seq_printf(seq, "%-5s %-10s %pM ",
426 bpqdev->axdev->name, bpqdev->ethdev->name,
427 bpqdev->dest_addr);
428
429 if (is_multicast_ether_addr(bpqdev->acpt_addr))
430 seq_printf(seq, "*\n");
431 else
432 seq_printf(seq, "%pM\n", bpqdev->acpt_addr);
433
434 }
435 return 0;
436}
437
438static const struct seq_operations bpq_seqops = {
439 .start = bpq_seq_start,
440 .next = bpq_seq_next,
441 .stop = bpq_seq_stop,
442 .show = bpq_seq_show,
443};
444#endif
445/* ------------------------------------------------------------------------ */
446
447static const struct net_device_ops bpq_netdev_ops = {
448 .ndo_open = bpq_open,
449 .ndo_stop = bpq_close,
450 .ndo_start_xmit = bpq_xmit,
451 .ndo_set_mac_address = bpq_set_mac_address,
452 .ndo_siocdevprivate = bpq_siocdevprivate,
453};
454
455static void bpq_setup(struct net_device *dev)
456{
457 dev->netdev_ops = &bpq_netdev_ops;
458 dev->needs_free_netdev = true;
459
460 dev->flags = 0;
461 dev->features = NETIF_F_LLTX; /* Allow recursion */
462
463#if IS_ENABLED(CONFIG_AX25)
464 dev->header_ops = &ax25_header_ops;
465#endif
466
467 dev->type = ARPHRD_AX25;
468 dev->hard_header_len = AX25_MAX_HEADER_LEN + AX25_BPQ_HEADER_LEN;
469 dev->mtu = AX25_DEF_PACLEN;
470 dev->addr_len = AX25_ADDR_LEN;
471
472 memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN);
473 dev_addr_set(dev, (u8 *)&ax25_defaddr);
474}
475
476/*
477 * Setup a new device.
478 */
479static int bpq_new_device(struct net_device *edev)
480{
481 int err;
482 struct net_device *ndev;
483 struct bpqdev *bpq;
484
485 ndev = alloc_netdev(sizeof(struct bpqdev), "bpq%d", NET_NAME_UNKNOWN,
486 bpq_setup);
487 if (!ndev)
488 return -ENOMEM;
489
490
491 bpq = netdev_priv(ndev);
492 dev_hold(edev);
493 bpq->ethdev = edev;
494 bpq->axdev = ndev;
495
496 eth_broadcast_addr(bpq->dest_addr);
497 eth_broadcast_addr(bpq->acpt_addr);
498
499 err = register_netdevice(ndev);
500 if (err)
501 goto error;
502 bpq_set_lockdep_class(ndev);
503
504 /* List protected by RTNL */
505 list_add_rcu(&bpq->bpq_list, &bpq_devices);
506 return 0;
507
508 error:
509 dev_put(edev);
510 free_netdev(ndev);
511 return err;
512
513}
514
515static void bpq_free_device(struct net_device *ndev)
516{
517 struct bpqdev *bpq = netdev_priv(ndev);
518
519 dev_put(bpq->ethdev);
520 list_del_rcu(&bpq->bpq_list);
521
522 unregister_netdevice(ndev);
523}
524
525/*
526 * Handle device status changes.
527 */
528static int bpq_device_event(struct notifier_block *this,
529 unsigned long event, void *ptr)
530{
531 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
532
533 if (!net_eq(dev_net(dev), &init_net))
534 return NOTIFY_DONE;
535
536 if (!dev_is_ethdev(dev) && !bpq_get_ax25_dev(dev))
537 return NOTIFY_DONE;
538
539 switch (event) {
540 case NETDEV_UP: /* new ethernet device -> new BPQ interface */
541 if (bpq_get_ax25_dev(dev) == NULL)
542 bpq_new_device(dev);
543 break;
544
545 case NETDEV_DOWN: /* ethernet device closed -> close BPQ interface */
546 if ((dev = bpq_get_ax25_dev(dev)) != NULL)
547 dev_close(dev);
548 break;
549
550 case NETDEV_UNREGISTER: /* ethernet device removed -> free BPQ interface */
551 if ((dev = bpq_get_ax25_dev(dev)) != NULL)
552 bpq_free_device(dev);
553 break;
554 default:
555 break;
556 }
557
558 return NOTIFY_DONE;
559}
560
561
562/* ------------------------------------------------------------------------ */
563
564/*
565 * Initialize driver. To be called from af_ax25 if not compiled as a
566 * module
567 */
568static int __init bpq_init_driver(void)
569{
570#ifdef CONFIG_PROC_FS
571 if (!proc_create_seq("bpqether", 0444, init_net.proc_net, &bpq_seqops)) {
572 printk(KERN_ERR
573 "bpq: cannot create /proc/net/bpqether entry.\n");
574 return -ENOENT;
575 }
576#endif /* CONFIG_PROC_FS */
577
578 dev_add_pack(&bpq_packet_type);
579
580 register_netdevice_notifier(&bpq_dev_notifier);
581
582 printk(banner);
583
584 return 0;
585}
586
587static void __exit bpq_cleanup_driver(void)
588{
589 struct bpqdev *bpq;
590
591 dev_remove_pack(&bpq_packet_type);
592
593 unregister_netdevice_notifier(&bpq_dev_notifier);
594
595 remove_proc_entry("bpqether", init_net.proc_net);
596
597 rtnl_lock();
598 while (!list_empty(&bpq_devices)) {
599 bpq = list_entry(bpq_devices.next, struct bpqdev, bpq_list);
600 bpq_free_device(bpq->axdev);
601 }
602 rtnl_unlock();
603}
604
605MODULE_AUTHOR("Joerg Reuter DL1BKE <jreuter@yaina.de>");
606MODULE_DESCRIPTION("Transmit and receive AX.25 packets over Ethernet");
607MODULE_LICENSE("GPL");
608module_init(bpq_init_driver);
609module_exit(bpq_cleanup_driver);
1/*
2 * G8BPQ compatible "AX.25 via ethernet" driver release 004
3 *
4 * This code REQUIRES 2.0.0 or higher/ NET3.029
5 *
6 * This module:
7 * This module is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 *
12 * This is a "pseudo" network driver to allow AX.25 over Ethernet
13 * using G8BPQ encapsulation. It has been extracted from the protocol
14 * implementation because
15 *
16 * - things got unreadable within the protocol stack
17 * - to cure the protocol stack from "feature-ism"
18 * - a protocol implementation shouldn't need to know on
19 * which hardware it is running
20 * - user-level programs like the AX.25 utilities shouldn't
21 * need to know about the hardware.
22 * - IP over ethernet encapsulated AX.25 was impossible
23 * - rxecho.c did not work
24 * - to have room for extensions
25 * - it just deserves to "live" as an own driver
26 *
27 * This driver can use any ethernet destination address, and can be
28 * limited to accept frames from one dedicated ethernet card only.
29 *
30 * Note that the driver sets up the BPQ devices automagically on
31 * startup or (if started before the "insmod" of an ethernet device)
32 * on "ifconfig up". It hopefully will remove the BPQ on "rmmod"ing
33 * the ethernet device (in fact: as soon as another ethernet or bpq
34 * device gets "ifconfig"ured).
35 *
36 * I have heard that several people are thinking of experiments
37 * with highspeed packet radio using existing ethernet cards.
38 * Well, this driver is prepared for this purpose, just add
39 * your tx key control and a txdelay / tailtime algorithm,
40 * probably some buffering, and /voila/...
41 *
42 * History
43 * BPQ 001 Joerg(DL1BKE) Extracted BPQ code from AX.25
44 * protocol stack and added my own
45 * yet existing patches
46 * BPQ 002 Joerg(DL1BKE) Scan network device list on
47 * startup.
48 * BPQ 003 Joerg(DL1BKE) Ethernet destination address
49 * and accepted source address
50 * can be configured by an ioctl()
51 * call.
52 * Fixed to match Linux networking
53 * changes - 2.1.15.
54 * BPQ 004 Joerg(DL1BKE) Fixed to not lock up on ifconfig.
55 */
56
57#include <linux/errno.h>
58#include <linux/types.h>
59#include <linux/socket.h>
60#include <linux/in.h>
61#include <linux/kernel.h>
62#include <linux/string.h>
63#include <linux/net.h>
64#include <linux/slab.h>
65#include <net/ax25.h>
66#include <linux/inet.h>
67#include <linux/netdevice.h>
68#include <linux/etherdevice.h>
69#include <linux/if_arp.h>
70#include <linux/skbuff.h>
71#include <net/sock.h>
72#include <linux/uaccess.h>
73#include <linux/mm.h>
74#include <linux/interrupt.h>
75#include <linux/notifier.h>
76#include <linux/proc_fs.h>
77#include <linux/seq_file.h>
78#include <linux/stat.h>
79#include <linux/module.h>
80#include <linux/init.h>
81#include <linux/rtnetlink.h>
82
83#include <net/ip.h>
84#include <net/arp.h>
85#include <net/net_namespace.h>
86
87#include <linux/bpqether.h>
88
89static const char banner[] __initconst = KERN_INFO \
90 "AX.25: bpqether driver version 004\n";
91
92static char bcast_addr[6]={0xFF,0xFF,0xFF,0xFF,0xFF,0xFF};
93
94static char bpq_eth_addr[6];
95
96static int bpq_rcv(struct sk_buff *, struct net_device *, struct packet_type *, struct net_device *);
97static int bpq_device_event(struct notifier_block *, unsigned long, void *);
98
99static struct packet_type bpq_packet_type __read_mostly = {
100 .type = cpu_to_be16(ETH_P_BPQ),
101 .func = bpq_rcv,
102};
103
104static struct notifier_block bpq_dev_notifier = {
105 .notifier_call = bpq_device_event,
106};
107
108
109struct bpqdev {
110 struct list_head bpq_list; /* list of bpq devices chain */
111 struct net_device *ethdev; /* link to ethernet device */
112 struct net_device *axdev; /* bpq device (bpq#) */
113 char dest_addr[6]; /* ether destination address */
114 char acpt_addr[6]; /* accept ether frames from this address only */
115};
116
117static LIST_HEAD(bpq_devices);
118
119/*
120 * bpqether network devices are paired with ethernet devices below them, so
121 * form a special "super class" of normal ethernet devices; split their locks
122 * off into a separate class since they always nest.
123 */
124static struct lock_class_key bpq_netdev_xmit_lock_key;
125static struct lock_class_key bpq_netdev_addr_lock_key;
126
127static void bpq_set_lockdep_class_one(struct net_device *dev,
128 struct netdev_queue *txq,
129 void *_unused)
130{
131 lockdep_set_class(&txq->_xmit_lock, &bpq_netdev_xmit_lock_key);
132}
133
134static void bpq_set_lockdep_class(struct net_device *dev)
135{
136 lockdep_set_class(&dev->addr_list_lock, &bpq_netdev_addr_lock_key);
137 netdev_for_each_tx_queue(dev, bpq_set_lockdep_class_one, NULL);
138}
139
140/* ------------------------------------------------------------------------ */
141
142
143/*
144 * Get the ethernet device for a BPQ device
145 */
146static inline struct net_device *bpq_get_ether_dev(struct net_device *dev)
147{
148 struct bpqdev *bpq = netdev_priv(dev);
149
150 return bpq ? bpq->ethdev : NULL;
151}
152
153/*
154 * Get the BPQ device for the ethernet device
155 */
156static inline struct net_device *bpq_get_ax25_dev(struct net_device *dev)
157{
158 struct bpqdev *bpq;
159
160 list_for_each_entry_rcu(bpq, &bpq_devices, bpq_list) {
161 if (bpq->ethdev == dev)
162 return bpq->axdev;
163 }
164 return NULL;
165}
166
167static inline int dev_is_ethdev(struct net_device *dev)
168{
169 return dev->type == ARPHRD_ETHER && strncmp(dev->name, "dummy", 5);
170}
171
172/* ------------------------------------------------------------------------ */
173
174
175/*
176 * Receive an AX.25 frame via an ethernet interface.
177 */
178static int bpq_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype, struct net_device *orig_dev)
179{
180 int len;
181 char * ptr;
182 struct ethhdr *eth;
183 struct bpqdev *bpq;
184
185 if (!net_eq(dev_net(dev), &init_net))
186 goto drop;
187
188 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
189 return NET_RX_DROP;
190
191 if (!pskb_may_pull(skb, sizeof(struct ethhdr)))
192 goto drop;
193
194 rcu_read_lock();
195 dev = bpq_get_ax25_dev(dev);
196
197 if (dev == NULL || !netif_running(dev))
198 goto drop_unlock;
199
200 /*
201 * if we want to accept frames from just one ethernet device
202 * we check the source address of the sender.
203 */
204
205 bpq = netdev_priv(dev);
206
207 eth = eth_hdr(skb);
208
209 if (!(bpq->acpt_addr[0] & 0x01) &&
210 !ether_addr_equal(eth->h_source, bpq->acpt_addr))
211 goto drop_unlock;
212
213 if (skb_cow(skb, sizeof(struct ethhdr)))
214 goto drop_unlock;
215
216 len = skb->data[0] + skb->data[1] * 256 - 5;
217
218 skb_pull(skb, 2); /* Remove the length bytes */
219 skb_trim(skb, len); /* Set the length of the data */
220
221 dev->stats.rx_packets++;
222 dev->stats.rx_bytes += len;
223
224 ptr = skb_push(skb, 1);
225 *ptr = 0;
226
227 skb->protocol = ax25_type_trans(skb, dev);
228 netif_rx(skb);
229unlock:
230
231 rcu_read_unlock();
232
233 return 0;
234drop_unlock:
235 kfree_skb(skb);
236 goto unlock;
237
238drop:
239 kfree_skb(skb);
240 return 0;
241}
242
243/*
244 * Send an AX.25 frame via an ethernet interface
245 */
246static netdev_tx_t bpq_xmit(struct sk_buff *skb, struct net_device *dev)
247{
248 unsigned char *ptr;
249 struct bpqdev *bpq;
250 struct net_device *orig_dev;
251 int size;
252
253 if (skb->protocol == htons(ETH_P_IP))
254 return ax25_ip_xmit(skb);
255
256 /*
257 * Just to be *really* sure not to send anything if the interface
258 * is down, the ethernet device may have gone.
259 */
260 if (!netif_running(dev)) {
261 kfree_skb(skb);
262 return NETDEV_TX_OK;
263 }
264
265 skb_pull(skb, 1); /* Drop KISS byte */
266 size = skb->len;
267
268 /*
269 * We're about to mess with the skb which may still shared with the
270 * generic networking code so unshare and ensure it's got enough
271 * space for the BPQ headers.
272 */
273 if (skb_cow(skb, AX25_BPQ_HEADER_LEN)) {
274 if (net_ratelimit())
275 pr_err("bpqether: out of memory\n");
276 kfree_skb(skb);
277
278 return NETDEV_TX_OK;
279 }
280
281 ptr = skb_push(skb, 2); /* Make space for length */
282
283 *ptr++ = (size + 5) % 256;
284 *ptr++ = (size + 5) / 256;
285
286 bpq = netdev_priv(dev);
287
288 orig_dev = dev;
289 if ((dev = bpq_get_ether_dev(dev)) == NULL) {
290 orig_dev->stats.tx_dropped++;
291 kfree_skb(skb);
292 return NETDEV_TX_OK;
293 }
294
295 skb->protocol = ax25_type_trans(skb, dev);
296 skb_reset_network_header(skb);
297 dev_hard_header(skb, dev, ETH_P_BPQ, bpq->dest_addr, NULL, 0);
298 dev->stats.tx_packets++;
299 dev->stats.tx_bytes+=skb->len;
300
301 dev_queue_xmit(skb);
302 netif_wake_queue(dev);
303 return NETDEV_TX_OK;
304}
305
306/*
307 * Set AX.25 callsign
308 */
309static int bpq_set_mac_address(struct net_device *dev, void *addr)
310{
311 struct sockaddr *sa = (struct sockaddr *)addr;
312
313 memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);
314
315 return 0;
316}
317
318/* Ioctl commands
319 *
320 * SIOCSBPQETHOPT reserved for enhancements
321 * SIOCSBPQETHADDR set the destination and accepted
322 * source ethernet address (broadcast
323 * or multicast: accept all)
324 */
325static int bpq_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
326{
327 struct bpq_ethaddr __user *ethaddr = ifr->ifr_data;
328 struct bpqdev *bpq = netdev_priv(dev);
329 struct bpq_req req;
330
331 if (!capable(CAP_NET_ADMIN))
332 return -EPERM;
333
334 switch (cmd) {
335 case SIOCSBPQETHOPT:
336 if (copy_from_user(&req, ifr->ifr_data, sizeof(struct bpq_req)))
337 return -EFAULT;
338 switch (req.cmd) {
339 case SIOCGBPQETHPARAM:
340 case SIOCSBPQETHPARAM:
341 default:
342 return -EINVAL;
343 }
344
345 break;
346
347 case SIOCSBPQETHADDR:
348 if (copy_from_user(bpq->dest_addr, ethaddr->destination, ETH_ALEN))
349 return -EFAULT;
350 if (copy_from_user(bpq->acpt_addr, ethaddr->accept, ETH_ALEN))
351 return -EFAULT;
352 break;
353
354 default:
355 return -EINVAL;
356 }
357
358 return 0;
359}
360
361/*
362 * open/close a device
363 */
364static int bpq_open(struct net_device *dev)
365{
366 netif_start_queue(dev);
367 return 0;
368}
369
370static int bpq_close(struct net_device *dev)
371{
372 netif_stop_queue(dev);
373 return 0;
374}
375
376
377/* ------------------------------------------------------------------------ */
378
379
380/*
381 * Proc filesystem
382 */
383static void *bpq_seq_start(struct seq_file *seq, loff_t *pos)
384 __acquires(RCU)
385{
386 int i = 1;
387 struct bpqdev *bpqdev;
388
389 rcu_read_lock();
390
391 if (*pos == 0)
392 return SEQ_START_TOKEN;
393
394 list_for_each_entry_rcu(bpqdev, &bpq_devices, bpq_list) {
395 if (i == *pos)
396 return bpqdev;
397 }
398 return NULL;
399}
400
401static void *bpq_seq_next(struct seq_file *seq, void *v, loff_t *pos)
402{
403 struct list_head *p;
404 struct bpqdev *bpqdev = v;
405
406 ++*pos;
407
408 if (v == SEQ_START_TOKEN)
409 p = rcu_dereference(list_next_rcu(&bpq_devices));
410 else
411 p = rcu_dereference(list_next_rcu(&bpqdev->bpq_list));
412
413 return (p == &bpq_devices) ? NULL
414 : list_entry(p, struct bpqdev, bpq_list);
415}
416
417static void bpq_seq_stop(struct seq_file *seq, void *v)
418 __releases(RCU)
419{
420 rcu_read_unlock();
421}
422
423
424static int bpq_seq_show(struct seq_file *seq, void *v)
425{
426 if (v == SEQ_START_TOKEN)
427 seq_puts(seq,
428 "dev ether destination accept from\n");
429 else {
430 const struct bpqdev *bpqdev = v;
431
432 seq_printf(seq, "%-5s %-10s %pM ",
433 bpqdev->axdev->name, bpqdev->ethdev->name,
434 bpqdev->dest_addr);
435
436 if (is_multicast_ether_addr(bpqdev->acpt_addr))
437 seq_printf(seq, "*\n");
438 else
439 seq_printf(seq, "%pM\n", bpqdev->acpt_addr);
440
441 }
442 return 0;
443}
444
445static const struct seq_operations bpq_seqops = {
446 .start = bpq_seq_start,
447 .next = bpq_seq_next,
448 .stop = bpq_seq_stop,
449 .show = bpq_seq_show,
450};
451
452static int bpq_info_open(struct inode *inode, struct file *file)
453{
454 return seq_open(file, &bpq_seqops);
455}
456
457static const struct file_operations bpq_info_fops = {
458 .owner = THIS_MODULE,
459 .open = bpq_info_open,
460 .read = seq_read,
461 .llseek = seq_lseek,
462 .release = seq_release,
463};
464
465
466/* ------------------------------------------------------------------------ */
467
468static const struct net_device_ops bpq_netdev_ops = {
469 .ndo_open = bpq_open,
470 .ndo_stop = bpq_close,
471 .ndo_start_xmit = bpq_xmit,
472 .ndo_set_mac_address = bpq_set_mac_address,
473 .ndo_do_ioctl = bpq_ioctl,
474};
475
476static void bpq_setup(struct net_device *dev)
477{
478 dev->netdev_ops = &bpq_netdev_ops;
479 dev->destructor = free_netdev;
480
481 memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN);
482 memcpy(dev->dev_addr, &ax25_defaddr, AX25_ADDR_LEN);
483
484 dev->flags = 0;
485 dev->features = NETIF_F_LLTX; /* Allow recursion */
486
487#if IS_ENABLED(CONFIG_AX25)
488 dev->header_ops = &ax25_header_ops;
489#endif
490
491 dev->type = ARPHRD_AX25;
492 dev->hard_header_len = AX25_MAX_HEADER_LEN + AX25_BPQ_HEADER_LEN;
493 dev->mtu = AX25_DEF_PACLEN;
494 dev->addr_len = AX25_ADDR_LEN;
495
496}
497
498/*
499 * Setup a new device.
500 */
501static int bpq_new_device(struct net_device *edev)
502{
503 int err;
504 struct net_device *ndev;
505 struct bpqdev *bpq;
506
507 ndev = alloc_netdev(sizeof(struct bpqdev), "bpq%d", NET_NAME_UNKNOWN,
508 bpq_setup);
509 if (!ndev)
510 return -ENOMEM;
511
512
513 bpq = netdev_priv(ndev);
514 dev_hold(edev);
515 bpq->ethdev = edev;
516 bpq->axdev = ndev;
517
518 memcpy(bpq->dest_addr, bcast_addr, sizeof(bpq_eth_addr));
519 memcpy(bpq->acpt_addr, bcast_addr, sizeof(bpq_eth_addr));
520
521 err = register_netdevice(ndev);
522 if (err)
523 goto error;
524 bpq_set_lockdep_class(ndev);
525
526 /* List protected by RTNL */
527 list_add_rcu(&bpq->bpq_list, &bpq_devices);
528 return 0;
529
530 error:
531 dev_put(edev);
532 free_netdev(ndev);
533 return err;
534
535}
536
537static void bpq_free_device(struct net_device *ndev)
538{
539 struct bpqdev *bpq = netdev_priv(ndev);
540
541 dev_put(bpq->ethdev);
542 list_del_rcu(&bpq->bpq_list);
543
544 unregister_netdevice(ndev);
545}
546
547/*
548 * Handle device status changes.
549 */
550static int bpq_device_event(struct notifier_block *this,
551 unsigned long event, void *ptr)
552{
553 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
554
555 if (!net_eq(dev_net(dev), &init_net))
556 return NOTIFY_DONE;
557
558 if (!dev_is_ethdev(dev))
559 return NOTIFY_DONE;
560
561 switch (event) {
562 case NETDEV_UP: /* new ethernet device -> new BPQ interface */
563 if (bpq_get_ax25_dev(dev) == NULL)
564 bpq_new_device(dev);
565 break;
566
567 case NETDEV_DOWN: /* ethernet device closed -> close BPQ interface */
568 if ((dev = bpq_get_ax25_dev(dev)) != NULL)
569 dev_close(dev);
570 break;
571
572 case NETDEV_UNREGISTER: /* ethernet device removed -> free BPQ interface */
573 if ((dev = bpq_get_ax25_dev(dev)) != NULL)
574 bpq_free_device(dev);
575 break;
576 default:
577 break;
578 }
579
580 return NOTIFY_DONE;
581}
582
583
584/* ------------------------------------------------------------------------ */
585
586/*
587 * Initialize driver. To be called from af_ax25 if not compiled as a
588 * module
589 */
590static int __init bpq_init_driver(void)
591{
592#ifdef CONFIG_PROC_FS
593 if (!proc_create("bpqether", S_IRUGO, init_net.proc_net,
594 &bpq_info_fops)) {
595 printk(KERN_ERR
596 "bpq: cannot create /proc/net/bpqether entry.\n");
597 return -ENOENT;
598 }
599#endif /* CONFIG_PROC_FS */
600
601 dev_add_pack(&bpq_packet_type);
602
603 register_netdevice_notifier(&bpq_dev_notifier);
604
605 printk(banner);
606
607 return 0;
608}
609
610static void __exit bpq_cleanup_driver(void)
611{
612 struct bpqdev *bpq;
613
614 dev_remove_pack(&bpq_packet_type);
615
616 unregister_netdevice_notifier(&bpq_dev_notifier);
617
618 remove_proc_entry("bpqether", init_net.proc_net);
619
620 rtnl_lock();
621 while (!list_empty(&bpq_devices)) {
622 bpq = list_entry(bpq_devices.next, struct bpqdev, bpq_list);
623 bpq_free_device(bpq->axdev);
624 }
625 rtnl_unlock();
626}
627
628MODULE_AUTHOR("Joerg Reuter DL1BKE <jreuter@yaina.de>");
629MODULE_DESCRIPTION("Transmit and receive AX.25 packets over Ethernet");
630MODULE_LICENSE("GPL");
631module_init(bpq_init_driver);
632module_exit(bpq_cleanup_driver);