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Merge tag 'io_uring-5.7-2020-05-22' of git://git.kernel.dk/linux-block
[thirdparty/linux.git] / drivers / net / hamradio / bpqether.c
CommitLineData
ee5d8f4d 1// SPDX-License-Identifier: GPL-2.0-or-later
1da177e4
LT
2/*
3 * G8BPQ compatible "AX.25 via ethernet" driver release 004
4 *
5 * This code REQUIRES 2.0.0 or higher/ NET3.029
6 *
1da177e4
LT
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
1da177e4
LT
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>
5a0e3ad6 59#include <linux/slab.h>
1da177e4
LT
60#include <net/ax25.h>
61#include <linux/inet.h>
62#include <linux/netdevice.h>
0795af57 63#include <linux/etherdevice.h>
1da177e4
LT
64#include <linux/if_arp.h>
65#include <linux/skbuff.h>
66#include <net/sock.h>
7c0f6ba6 67#include <linux/uaccess.h>
1da177e4
LT
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>
1da177e4
LT
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>
457c4cbc 80#include <net/net_namespace.h>
1da177e4
LT
81
82#include <linux/bpqether.h>
83
afa8c78b 84static const char banner[] __initconst = KERN_INFO \
eb33ae24 85 "AX.25: bpqether driver version 004\n";
1da177e4 86
f2ccd8fa 87static int bpq_rcv(struct sk_buff *, struct net_device *, struct packet_type *, struct net_device *);
1da177e4 88static int bpq_device_event(struct notifier_block *, unsigned long, void *);
1da177e4 89
7546dd97 90static struct packet_type bpq_packet_type __read_mostly = {
09640e63 91 .type = cpu_to_be16(ETH_P_BPQ),
1da177e4
LT
92 .func = bpq_rcv,
93};
94
95static struct notifier_block bpq_dev_notifier = {
351638e7 96 .notifier_call = bpq_device_event,
1da177e4
LT
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#) */
1da177e4
LT
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
1da177e4
LT
110/* ------------------------------------------------------------------------ */
111
112
113/*
114 * Get the ethernet device for a BPQ device
115 */
116static inline struct net_device *bpq_get_ether_dev(struct net_device *dev)
117{
118 struct bpqdev *bpq = netdev_priv(dev);
119
120 return bpq ? bpq->ethdev : NULL;
121}
122
123/*
124 * Get the BPQ device for the ethernet device
125 */
126static inline struct net_device *bpq_get_ax25_dev(struct net_device *dev)
127{
128 struct bpqdev *bpq;
129
95f59bf8
MB
130 list_for_each_entry_rcu(bpq, &bpq_devices, bpq_list,
131 lockdep_rtnl_is_held()) {
1da177e4
LT
132 if (bpq->ethdev == dev)
133 return bpq->axdev;
134 }
135 return NULL;
136}
137
138static inline int dev_is_ethdev(struct net_device *dev)
139{
807540ba 140 return dev->type == ARPHRD_ETHER && strncmp(dev->name, "dummy", 5);
1da177e4
LT
141}
142
143/* ------------------------------------------------------------------------ */
144
145
146/*
147 * Receive an AX.25 frame via an ethernet interface.
148 */
f2ccd8fa 149static int bpq_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype, struct net_device *orig_dev)
1da177e4
LT
150{
151 int len;
152 char * ptr;
153 struct ethhdr *eth;
154 struct bpqdev *bpq;
155
09ad9bc7 156 if (!net_eq(dev_net(dev), &init_net))
e730c155
EB
157 goto drop;
158
1da177e4
LT
159 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
160 return NET_RX_DROP;
161
162 if (!pskb_may_pull(skb, sizeof(struct ethhdr)))
163 goto drop;
164
165 rcu_read_lock();
166 dev = bpq_get_ax25_dev(dev);
167
168 if (dev == NULL || !netif_running(dev))
169 goto drop_unlock;
170
171 /*
172 * if we want to accept frames from just one ethernet device
173 * we check the source address of the sender.
174 */
175
176 bpq = netdev_priv(dev);
177
178 eth = eth_hdr(skb);
179
180 if (!(bpq->acpt_addr[0] & 0x01) &&
dc050c9e 181 !ether_addr_equal(eth->h_source, bpq->acpt_addr))
1da177e4
LT
182 goto drop_unlock;
183
184 if (skb_cow(skb, sizeof(struct ethhdr)))
185 goto drop_unlock;
186
187 len = skb->data[0] + skb->data[1] * 256 - 5;
188
189 skb_pull(skb, 2); /* Remove the length bytes */
190 skb_trim(skb, len); /* Set the length of the data */
191
f57505fd
SH
192 dev->stats.rx_packets++;
193 dev->stats.rx_bytes += len;
1da177e4
LT
194
195 ptr = skb_push(skb, 1);
196 *ptr = 0;
197
56cb5156 198 skb->protocol = ax25_type_trans(skb, dev);
1da177e4 199 netif_rx(skb);
1da177e4
LT
200unlock:
201
202 rcu_read_unlock();
203
204 return 0;
205drop_unlock:
206 kfree_skb(skb);
207 goto unlock;
208
209drop:
210 kfree_skb(skb);
211 return 0;
212}
213
214/*
215 * Send an AX.25 frame via an ethernet interface
216 */
36e4d64a 217static netdev_tx_t bpq_xmit(struct sk_buff *skb, struct net_device *dev)
1da177e4 218{
1da177e4
LT
219 unsigned char *ptr;
220 struct bpqdev *bpq;
f65d1f08 221 struct net_device *orig_dev;
1da177e4
LT
222 int size;
223
1d5da757
EB
224 if (skb->protocol == htons(ETH_P_IP))
225 return ax25_ip_xmit(skb);
226
1da177e4
LT
227 /*
228 * Just to be *really* sure not to send anything if the interface
229 * is down, the ethernet device may have gone.
230 */
231 if (!netif_running(dev)) {
232 kfree_skb(skb);
d77eeb70 233 return NETDEV_TX_OK;
1da177e4
LT
234 }
235
3eb00275 236 skb_pull(skb, 1); /* Drop KISS byte */
1da177e4
LT
237 size = skb->len;
238
239 /*
3eb00275
RB
240 * We're about to mess with the skb which may still shared with the
241 * generic networking code so unshare and ensure it's got enough
242 * space for the BPQ headers.
1da177e4 243 */
3eb00275
RB
244 if (skb_cow(skb, AX25_BPQ_HEADER_LEN)) {
245 if (net_ratelimit())
246 pr_err("bpqether: out of memory\n");
1da177e4 247 kfree_skb(skb);
3eb00275
RB
248
249 return NETDEV_TX_OK;
1da177e4
LT
250 }
251
3eb00275 252 ptr = skb_push(skb, 2); /* Make space for length */
1da177e4
LT
253
254 *ptr++ = (size + 5) % 256;
255 *ptr++ = (size + 5) / 256;
256
257 bpq = netdev_priv(dev);
258
f65d1f08 259 orig_dev = dev;
1da177e4 260 if ((dev = bpq_get_ether_dev(dev)) == NULL) {
f65d1f08 261 orig_dev->stats.tx_dropped++;
1da177e4 262 kfree_skb(skb);
98ca4a46 263 return NETDEV_TX_OK;
1da177e4
LT
264 }
265
56cb5156 266 skb->protocol = ax25_type_trans(skb, dev);
c1d2bbe1 267 skb_reset_network_header(skb);
0c4e8581 268 dev_hard_header(skb, dev, ETH_P_BPQ, bpq->dest_addr, NULL, 0);
f57505fd
SH
269 dev->stats.tx_packets++;
270 dev->stats.tx_bytes+=skb->len;
1da177e4
LT
271
272 dev_queue_xmit(skb);
273 netif_wake_queue(dev);
6ed10654 274 return NETDEV_TX_OK;
1da177e4
LT
275}
276
1da177e4
LT
277/*
278 * Set AX.25 callsign
279 */
280static int bpq_set_mac_address(struct net_device *dev, void *addr)
281{
282 struct sockaddr *sa = (struct sockaddr *)addr;
283
284 memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);
285
286 return 0;
287}
288
289/* Ioctl commands
290 *
291 * SIOCSBPQETHOPT reserved for enhancements
292 * SIOCSBPQETHADDR set the destination and accepted
293 * source ethernet address (broadcast
294 * or multicast: accept all)
295 */
296static int bpq_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
297{
298 struct bpq_ethaddr __user *ethaddr = ifr->ifr_data;
299 struct bpqdev *bpq = netdev_priv(dev);
300 struct bpq_req req;
301
302 if (!capable(CAP_NET_ADMIN))
303 return -EPERM;
304
305 switch (cmd) {
306 case SIOCSBPQETHOPT:
307 if (copy_from_user(&req, ifr->ifr_data, sizeof(struct bpq_req)))
308 return -EFAULT;
309 switch (req.cmd) {
310 case SIOCGBPQETHPARAM:
311 case SIOCSBPQETHPARAM:
312 default:
313 return -EINVAL;
314 }
315
316 break;
317
318 case SIOCSBPQETHADDR:
319 if (copy_from_user(bpq->dest_addr, ethaddr->destination, ETH_ALEN))
320 return -EFAULT;
321 if (copy_from_user(bpq->acpt_addr, ethaddr->accept, ETH_ALEN))
322 return -EFAULT;
323 break;
324
325 default:
326 return -EINVAL;
327 }
328
329 return 0;
330}
331
332/*
333 * open/close a device
334 */
335static int bpq_open(struct net_device *dev)
336{
337 netif_start_queue(dev);
338 return 0;
339}
340
341static int bpq_close(struct net_device *dev)
342{
343 netif_stop_queue(dev);
344 return 0;
345}
346
347
348/* ------------------------------------------------------------------------ */
349
350
351/*
352 * Proc filesystem
353 */
1da177e4 354static void *bpq_seq_start(struct seq_file *seq, loff_t *pos)
e334f564 355 __acquires(RCU)
1da177e4
LT
356{
357 int i = 1;
358 struct bpqdev *bpqdev;
359
360 rcu_read_lock();
361
362 if (*pos == 0)
363 return SEQ_START_TOKEN;
364
bc0a7438 365 list_for_each_entry_rcu(bpqdev, &bpq_devices, bpq_list) {
1da177e4
LT
366 if (i == *pos)
367 return bpqdev;
368 }
369 return NULL;
370}
371
372static void *bpq_seq_next(struct seq_file *seq, void *v, loff_t *pos)
373{
374 struct list_head *p;
13707f9e 375 struct bpqdev *bpqdev = v;
1da177e4
LT
376
377 ++*pos;
378
379 if (v == SEQ_START_TOKEN)
13707f9e 380 p = rcu_dereference(list_next_rcu(&bpq_devices));
1da177e4 381 else
13707f9e 382 p = rcu_dereference(list_next_rcu(&bpqdev->bpq_list));
1da177e4
LT
383
384 return (p == &bpq_devices) ? NULL
b34bd06e 385 : list_entry(p, struct bpqdev, bpq_list);
1da177e4
LT
386}
387
388static void bpq_seq_stop(struct seq_file *seq, void *v)
e334f564 389 __releases(RCU)
1da177e4
LT
390{
391 rcu_read_unlock();
392}
393
394
395static int bpq_seq_show(struct seq_file *seq, void *v)
396{
397 if (v == SEQ_START_TOKEN)
398 seq_puts(seq,
399 "dev ether destination accept from\n");
400 else {
401 const struct bpqdev *bpqdev = v;
402
e174961c 403 seq_printf(seq, "%-5s %-10s %pM ",
1da177e4 404 bpqdev->axdev->name, bpqdev->ethdev->name,
e174961c 405 bpqdev->dest_addr);
1da177e4 406
0795af57
JP
407 if (is_multicast_ether_addr(bpqdev->acpt_addr))
408 seq_printf(seq, "*\n");
409 else
e174961c 410 seq_printf(seq, "%pM\n", bpqdev->acpt_addr);
1da177e4
LT
411
412 }
413 return 0;
414}
415
4101dec9 416static const struct seq_operations bpq_seqops = {
1da177e4
LT
417 .start = bpq_seq_start,
418 .next = bpq_seq_next,
419 .stop = bpq_seq_stop,
420 .show = bpq_seq_show,
421};
422
1da177e4
LT
423/* ------------------------------------------------------------------------ */
424
283767e7
SH
425static const struct net_device_ops bpq_netdev_ops = {
426 .ndo_open = bpq_open,
427 .ndo_stop = bpq_close,
428 .ndo_start_xmit = bpq_xmit,
429 .ndo_set_mac_address = bpq_set_mac_address,
430 .ndo_do_ioctl = bpq_ioctl,
431};
1da177e4
LT
432
433static void bpq_setup(struct net_device *dev)
434{
283767e7 435 dev->netdev_ops = &bpq_netdev_ops;
cf124db5 436 dev->needs_free_netdev = true;
1da177e4 437
15b1c0e8
RB
438 memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN);
439 memcpy(dev->dev_addr, &ax25_defaddr, AX25_ADDR_LEN);
1da177e4
LT
440
441 dev->flags = 0;
aa43c5ff 442 dev->features = NETIF_F_LLTX; /* Allow recursion */
1da177e4 443
5f94bebe 444#if IS_ENABLED(CONFIG_AX25)
3b04ddde 445 dev->header_ops = &ax25_header_ops;
1da177e4
LT
446#endif
447
448 dev->type = ARPHRD_AX25;
449 dev->hard_header_len = AX25_MAX_HEADER_LEN + AX25_BPQ_HEADER_LEN;
450 dev->mtu = AX25_DEF_PACLEN;
451 dev->addr_len = AX25_ADDR_LEN;
452
453}
454
455/*
456 * Setup a new device.
457 */
458static int bpq_new_device(struct net_device *edev)
459{
460 int err;
461 struct net_device *ndev;
462 struct bpqdev *bpq;
463
c835a677
TG
464 ndev = alloc_netdev(sizeof(struct bpqdev), "bpq%d", NET_NAME_UNKNOWN,
465 bpq_setup);
1da177e4
LT
466 if (!ndev)
467 return -ENOMEM;
468
469
470 bpq = netdev_priv(ndev);
471 dev_hold(edev);
472 bpq->ethdev = edev;
473 bpq->axdev = ndev;
474
4e8439aa
SA
475 eth_broadcast_addr(bpq->dest_addr);
476 eth_broadcast_addr(bpq->acpt_addr);
1da177e4 477
1da177e4
LT
478 err = register_netdevice(ndev);
479 if (err)
480 goto error;
481
482 /* List protected by RTNL */
483 list_add_rcu(&bpq->bpq_list, &bpq_devices);
484 return 0;
485
486 error:
487 dev_put(edev);
488 free_netdev(ndev);
489 return err;
490
491}
492
493static void bpq_free_device(struct net_device *ndev)
494{
495 struct bpqdev *bpq = netdev_priv(ndev);
496
497 dev_put(bpq->ethdev);
498 list_del_rcu(&bpq->bpq_list);
499
500 unregister_netdevice(ndev);
501}
502
503/*
504 * Handle device status changes.
505 */
351638e7
JP
506static int bpq_device_event(struct notifier_block *this,
507 unsigned long event, void *ptr)
1da177e4 508{
351638e7 509 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1da177e4 510
09ad9bc7 511 if (!net_eq(dev_net(dev), &init_net))
e9dc8653
EB
512 return NOTIFY_DONE;
513
1da177e4
LT
514 if (!dev_is_ethdev(dev))
515 return NOTIFY_DONE;
516
1da177e4
LT
517 switch (event) {
518 case NETDEV_UP: /* new ethernet device -> new BPQ interface */
519 if (bpq_get_ax25_dev(dev) == NULL)
520 bpq_new_device(dev);
521 break;
522
523 case NETDEV_DOWN: /* ethernet device closed -> close BPQ interface */
524 if ((dev = bpq_get_ax25_dev(dev)) != NULL)
525 dev_close(dev);
526 break;
527
528 case NETDEV_UNREGISTER: /* ethernet device removed -> free BPQ interface */
529 if ((dev = bpq_get_ax25_dev(dev)) != NULL)
530 bpq_free_device(dev);
531 break;
532 default:
533 break;
534 }
1da177e4
LT
535
536 return NOTIFY_DONE;
537}
538
539
540/* ------------------------------------------------------------------------ */
541
542/*
543 * Initialize driver. To be called from af_ax25 if not compiled as a
544 * module
545 */
546static int __init bpq_init_driver(void)
547{
548#ifdef CONFIG_PROC_FS
fddda2b7 549 if (!proc_create_seq("bpqether", 0444, init_net.proc_net, &bpq_seqops)) {
1da177e4
LT
550 printk(KERN_ERR
551 "bpq: cannot create /proc/net/bpqether entry.\n");
552 return -ENOENT;
553 }
554#endif /* CONFIG_PROC_FS */
555
556 dev_add_pack(&bpq_packet_type);
557
558 register_netdevice_notifier(&bpq_dev_notifier);
559
560 printk(banner);
561
562 return 0;
563}
564
565static void __exit bpq_cleanup_driver(void)
566{
567 struct bpqdev *bpq;
568
569 dev_remove_pack(&bpq_packet_type);
570
571 unregister_netdevice_notifier(&bpq_dev_notifier);
572
ece31ffd 573 remove_proc_entry("bpqether", init_net.proc_net);
1da177e4
LT
574
575 rtnl_lock();
576 while (!list_empty(&bpq_devices)) {
577 bpq = list_entry(bpq_devices.next, struct bpqdev, bpq_list);
578 bpq_free_device(bpq->axdev);
579 }
580 rtnl_unlock();
581}
582
583MODULE_AUTHOR("Joerg Reuter DL1BKE <jreuter@yaina.de>");
584MODULE_DESCRIPTION("Transmit and receive AX.25 packets over Ethernet");
585MODULE_LICENSE("GPL");
586module_init(bpq_init_driver);
587module_exit(bpq_cleanup_driver);