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1/*
2 * Generic HDLC support routines for Linux
3 *
4 * Copyright (C) 1999 - 2008 Krzysztof Halasa <khc@pm.waw.pl>
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of version 2 of the GNU General Public License
8 * as published by the Free Software Foundation.
9 *
10 * Currently supported:
11 * * raw IP-in-HDLC
12 * * Cisco HDLC
13 * * Frame Relay with ANSI or CCITT LMI (both user and network side)
14 * * PPP
15 * * X.25
16 *
17 * Use sethdlc utility to set line parameters, protocol and PVCs
18 *
19 * How does it work:
20 * - proto->open(), close(), start(), stop() calls are serialized.
21 * The order is: open, [ start, stop ... ] close ...
22 * - proto->start() and stop() are called with spin_lock_irq held.
23 */
24
25#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
26
27#include <linux/errno.h>
28#include <linux/hdlc.h>
29#include <linux/if_arp.h>
30#include <linux/inetdevice.h>
31#include <linux/init.h>
32#include <linux/kernel.h>
33#include <linux/module.h>
34#include <linux/notifier.h>
35#include <linux/pkt_sched.h>
36#include <linux/poll.h>
37#include <linux/rtnetlink.h>
38#include <linux/skbuff.h>
39#include <linux/slab.h>
40#include <net/net_namespace.h>
41
42
43static const char* version = "HDLC support module revision 1.22";
44
45#undef DEBUG_LINK
46
47static struct hdlc_proto *first_proto;
48
49static int hdlc_rcv(struct sk_buff *skb, struct net_device *dev,
50 struct packet_type *p, struct net_device *orig_dev)
51{
52 struct hdlc_device *hdlc = dev_to_hdlc(dev);
53
54 if (!net_eq(dev_net(dev), &init_net)) {
55 kfree_skb(skb);
56 return 0;
57 }
58
59 BUG_ON(!hdlc->proto->netif_rx);
60 return hdlc->proto->netif_rx(skb);
61}
62
63netdev_tx_t hdlc_start_xmit(struct sk_buff *skb, struct net_device *dev)
64{
65 hdlc_device *hdlc = dev_to_hdlc(dev);
66
67 if (hdlc->proto->xmit)
68 return hdlc->proto->xmit(skb, dev);
69
70 return hdlc->xmit(skb, dev); /* call hardware driver directly */
71}
72
73static inline void hdlc_proto_start(struct net_device *dev)
74{
75 hdlc_device *hdlc = dev_to_hdlc(dev);
76 if (hdlc->proto->start)
77 hdlc->proto->start(dev);
78}
79
80
81
82static inline void hdlc_proto_stop(struct net_device *dev)
83{
84 hdlc_device *hdlc = dev_to_hdlc(dev);
85 if (hdlc->proto->stop)
86 hdlc->proto->stop(dev);
87}
88
89
90
91static int hdlc_device_event(struct notifier_block *this, unsigned long event,
92 void *ptr)
93{
94 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
95 hdlc_device *hdlc;
96 unsigned long flags;
97 int on;
98
99 if (!net_eq(dev_net(dev), &init_net))
100 return NOTIFY_DONE;
101
102 if (!(dev->priv_flags & IFF_WAN_HDLC))
103 return NOTIFY_DONE; /* not an HDLC device */
104
105 if (event != NETDEV_CHANGE)
106 return NOTIFY_DONE; /* Only interested in carrier changes */
107
108 on = netif_carrier_ok(dev);
109
110#ifdef DEBUG_LINK
111 printk(KERN_DEBUG "%s: hdlc_device_event NETDEV_CHANGE, carrier %i\n",
112 dev->name, on);
113#endif
114
115 hdlc = dev_to_hdlc(dev);
116 spin_lock_irqsave(&hdlc->state_lock, flags);
117
118 if (hdlc->carrier == on)
119 goto carrier_exit; /* no change in DCD line level */
120
121 hdlc->carrier = on;
122
123 if (!hdlc->open)
124 goto carrier_exit;
125
126 if (hdlc->carrier) {
127 netdev_info(dev, "Carrier detected\n");
128 hdlc_proto_start(dev);
129 } else {
130 netdev_info(dev, "Carrier lost\n");
131 hdlc_proto_stop(dev);
132 }
133
134carrier_exit:
135 spin_unlock_irqrestore(&hdlc->state_lock, flags);
136 return NOTIFY_DONE;
137}
138
139
140
141/* Must be called by hardware driver when HDLC device is being opened */
142int hdlc_open(struct net_device *dev)
143{
144 hdlc_device *hdlc = dev_to_hdlc(dev);
145#ifdef DEBUG_LINK
146 printk(KERN_DEBUG "%s: hdlc_open() carrier %i open %i\n", dev->name,
147 hdlc->carrier, hdlc->open);
148#endif
149
150 if (hdlc->proto == NULL)
151 return -ENOSYS; /* no protocol attached */
152
153 if (hdlc->proto->open) {
154 int result = hdlc->proto->open(dev);
155 if (result)
156 return result;
157 }
158
159 spin_lock_irq(&hdlc->state_lock);
160
161 if (hdlc->carrier) {
162 netdev_info(dev, "Carrier detected\n");
163 hdlc_proto_start(dev);
164 } else
165 netdev_info(dev, "No carrier\n");
166
167 hdlc->open = 1;
168
169 spin_unlock_irq(&hdlc->state_lock);
170 return 0;
171}
172
173
174
175/* Must be called by hardware driver when HDLC device is being closed */
176void hdlc_close(struct net_device *dev)
177{
178 hdlc_device *hdlc = dev_to_hdlc(dev);
179#ifdef DEBUG_LINK
180 printk(KERN_DEBUG "%s: hdlc_close() carrier %i open %i\n", dev->name,
181 hdlc->carrier, hdlc->open);
182#endif
183
184 spin_lock_irq(&hdlc->state_lock);
185
186 hdlc->open = 0;
187 if (hdlc->carrier)
188 hdlc_proto_stop(dev);
189
190 spin_unlock_irq(&hdlc->state_lock);
191
192 if (hdlc->proto->close)
193 hdlc->proto->close(dev);
194}
195
196
197
198int hdlc_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
199{
200 struct hdlc_proto *proto = first_proto;
201 int result;
202
203 if (cmd != SIOCWANDEV)
204 return -EINVAL;
205
206 if (dev_to_hdlc(dev)->proto) {
207 result = dev_to_hdlc(dev)->proto->ioctl(dev, ifr);
208 if (result != -EINVAL)
209 return result;
210 }
211
212 /* Not handled by currently attached protocol (if any) */
213
214 while (proto) {
215 if ((result = proto->ioctl(dev, ifr)) != -EINVAL)
216 return result;
217 proto = proto->next;
218 }
219 return -EINVAL;
220}
221
222static const struct header_ops hdlc_null_ops;
223
224static void hdlc_setup_dev(struct net_device *dev)
225{
226 /* Re-init all variables changed by HDLC protocol drivers,
227 * including ether_setup() called from hdlc_raw_eth.c.
228 */
229 dev->flags = IFF_POINTOPOINT | IFF_NOARP;
230 dev->priv_flags = IFF_WAN_HDLC;
231 dev->mtu = HDLC_MAX_MTU;
232 dev->min_mtu = 68;
233 dev->max_mtu = HDLC_MAX_MTU;
234 dev->type = ARPHRD_RAWHDLC;
235 dev->hard_header_len = 16;
236 dev->addr_len = 0;
237 dev->header_ops = &hdlc_null_ops;
238}
239
240static void hdlc_setup(struct net_device *dev)
241{
242 hdlc_device *hdlc = dev_to_hdlc(dev);
243
244 hdlc_setup_dev(dev);
245 hdlc->carrier = 1;
246 hdlc->open = 0;
247 spin_lock_init(&hdlc->state_lock);
248}
249
250struct net_device *alloc_hdlcdev(void *priv)
251{
252 struct net_device *dev;
253 dev = alloc_netdev(sizeof(struct hdlc_device), "hdlc%d",
254 NET_NAME_UNKNOWN, hdlc_setup);
255 if (dev)
256 dev_to_hdlc(dev)->priv = priv;
257 return dev;
258}
259
260void unregister_hdlc_device(struct net_device *dev)
261{
262 rtnl_lock();
263 detach_hdlc_protocol(dev);
264 unregister_netdevice(dev);
265 rtnl_unlock();
266}
267
268
269
270int attach_hdlc_protocol(struct net_device *dev, struct hdlc_proto *proto,
271 size_t size)
272{
273 int err;
274
275 err = detach_hdlc_protocol(dev);
276 if (err)
277 return err;
278
279 if (!try_module_get(proto->module))
280 return -ENOSYS;
281
282 if (size) {
283 dev_to_hdlc(dev)->state = kmalloc(size, GFP_KERNEL);
284 if (dev_to_hdlc(dev)->state == NULL) {
285 module_put(proto->module);
286 return -ENOBUFS;
287 }
288 }
289 dev_to_hdlc(dev)->proto = proto;
290
291 return 0;
292}
293
294
295int detach_hdlc_protocol(struct net_device *dev)
296{
297 hdlc_device *hdlc = dev_to_hdlc(dev);
298 int err;
299
300 if (hdlc->proto) {
301 err = call_netdevice_notifiers(NETDEV_PRE_TYPE_CHANGE, dev);
302 err = notifier_to_errno(err);
303 if (err) {
304 netdev_err(dev, "Refused to change device type\n");
305 return err;
306 }
307
308 if (hdlc->proto->detach)
309 hdlc->proto->detach(dev);
310 module_put(hdlc->proto->module);
311 hdlc->proto = NULL;
312 }
313 kfree(hdlc->state);
314 hdlc->state = NULL;
315 hdlc_setup_dev(dev);
316
317 return 0;
318}
319
320
321void register_hdlc_protocol(struct hdlc_proto *proto)
322{
323 rtnl_lock();
324 proto->next = first_proto;
325 first_proto = proto;
326 rtnl_unlock();
327}
328
329
330void unregister_hdlc_protocol(struct hdlc_proto *proto)
331{
332 struct hdlc_proto **p;
333
334 rtnl_lock();
335 p = &first_proto;
336 while (*p != proto) {
337 BUG_ON(!*p);
338 p = &((*p)->next);
339 }
340 *p = proto->next;
341 rtnl_unlock();
342}
343
344
345
346MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
347MODULE_DESCRIPTION("HDLC support module");
348MODULE_LICENSE("GPL v2");
349
350EXPORT_SYMBOL(hdlc_start_xmit);
351EXPORT_SYMBOL(hdlc_open);
352EXPORT_SYMBOL(hdlc_close);
353EXPORT_SYMBOL(hdlc_ioctl);
354EXPORT_SYMBOL(alloc_hdlcdev);
355EXPORT_SYMBOL(unregister_hdlc_device);
356EXPORT_SYMBOL(register_hdlc_protocol);
357EXPORT_SYMBOL(unregister_hdlc_protocol);
358EXPORT_SYMBOL(attach_hdlc_protocol);
359EXPORT_SYMBOL(detach_hdlc_protocol);
360
361static struct packet_type hdlc_packet_type __read_mostly = {
362 .type = cpu_to_be16(ETH_P_HDLC),
363 .func = hdlc_rcv,
364};
365
366
367static struct notifier_block hdlc_notifier = {
368 .notifier_call = hdlc_device_event,
369};
370
371
372static int __init hdlc_module_init(void)
373{
374 int result;
375
376 pr_info("%s\n", version);
377 if ((result = register_netdevice_notifier(&hdlc_notifier)) != 0)
378 return result;
379 dev_add_pack(&hdlc_packet_type);
380 return 0;
381}
382
383
384
385static void __exit hdlc_module_exit(void)
386{
387 dev_remove_pack(&hdlc_packet_type);
388 unregister_netdevice_notifier(&hdlc_notifier);
389}
390
391
392module_init(hdlc_module_init);
393module_exit(hdlc_module_exit);
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Generic HDLC support routines for Linux
4 *
5 * Copyright (C) 1999 - 2008 Krzysztof Halasa <khc@pm.waw.pl>
6 *
7 * Currently supported:
8 * * raw IP-in-HDLC
9 * * Cisco HDLC
10 * * Frame Relay with ANSI or CCITT LMI (both user and network side)
11 * * PPP
12 * * X.25
13 *
14 * Use sethdlc utility to set line parameters, protocol and PVCs
15 *
16 * How does it work:
17 * - proto->open(), close(), start(), stop() calls are serialized.
18 * The order is: open, [ start, stop ... ] close ...
19 * - proto->start() and stop() are called with spin_lock_irq held.
20 */
21
22#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
23
24#include <linux/errno.h>
25#include <linux/hdlc.h>
26#include <linux/if_arp.h>
27#include <linux/inetdevice.h>
28#include <linux/init.h>
29#include <linux/kernel.h>
30#include <linux/module.h>
31#include <linux/notifier.h>
32#include <linux/pkt_sched.h>
33#include <linux/poll.h>
34#include <linux/rtnetlink.h>
35#include <linux/skbuff.h>
36#include <linux/slab.h>
37#include <net/net_namespace.h>
38
39static const char *version = "HDLC support module revision 1.22";
40
41#undef DEBUG_LINK
42
43static struct hdlc_proto *first_proto;
44
45static int hdlc_rcv(struct sk_buff *skb, struct net_device *dev,
46 struct packet_type *p, struct net_device *orig_dev)
47{
48 struct hdlc_device *hdlc;
49
50 /* First make sure "dev" is an HDLC device */
51 if (!(dev->priv_flags & IFF_WAN_HDLC)) {
52 kfree_skb(skb);
53 return NET_RX_SUCCESS;
54 }
55
56 hdlc = dev_to_hdlc(dev);
57
58 if (!net_eq(dev_net(dev), &init_net)) {
59 kfree_skb(skb);
60 return 0;
61 }
62
63 BUG_ON(!hdlc->proto->netif_rx);
64 return hdlc->proto->netif_rx(skb);
65}
66
67netdev_tx_t hdlc_start_xmit(struct sk_buff *skb, struct net_device *dev)
68{
69 hdlc_device *hdlc = dev_to_hdlc(dev);
70
71 if (hdlc->proto->xmit)
72 return hdlc->proto->xmit(skb, dev);
73
74 return hdlc->xmit(skb, dev); /* call hardware driver directly */
75}
76EXPORT_SYMBOL(hdlc_start_xmit);
77
78static inline void hdlc_proto_start(struct net_device *dev)
79{
80 hdlc_device *hdlc = dev_to_hdlc(dev);
81
82 if (hdlc->proto->start)
83 hdlc->proto->start(dev);
84}
85
86static inline void hdlc_proto_stop(struct net_device *dev)
87{
88 hdlc_device *hdlc = dev_to_hdlc(dev);
89
90 if (hdlc->proto->stop)
91 hdlc->proto->stop(dev);
92}
93
94static int hdlc_device_event(struct notifier_block *this, unsigned long event,
95 void *ptr)
96{
97 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
98 hdlc_device *hdlc;
99 unsigned long flags;
100 int on;
101
102 if (!net_eq(dev_net(dev), &init_net))
103 return NOTIFY_DONE;
104
105 if (!(dev->priv_flags & IFF_WAN_HDLC))
106 return NOTIFY_DONE; /* not an HDLC device */
107
108 if (event != NETDEV_CHANGE)
109 return NOTIFY_DONE; /* Only interested in carrier changes */
110
111 on = netif_carrier_ok(dev);
112
113#ifdef DEBUG_LINK
114 printk(KERN_DEBUG "%s: hdlc_device_event NETDEV_CHANGE, carrier %i\n",
115 dev->name, on);
116#endif
117
118 hdlc = dev_to_hdlc(dev);
119 spin_lock_irqsave(&hdlc->state_lock, flags);
120
121 if (hdlc->carrier == on)
122 goto carrier_exit; /* no change in DCD line level */
123
124 hdlc->carrier = on;
125
126 if (!hdlc->open)
127 goto carrier_exit;
128
129 if (hdlc->carrier) {
130 netdev_info(dev, "Carrier detected\n");
131 hdlc_proto_start(dev);
132 } else {
133 netdev_info(dev, "Carrier lost\n");
134 hdlc_proto_stop(dev);
135 }
136
137carrier_exit:
138 spin_unlock_irqrestore(&hdlc->state_lock, flags);
139 return NOTIFY_DONE;
140}
141
142/* Must be called by hardware driver when HDLC device is being opened */
143int hdlc_open(struct net_device *dev)
144{
145 hdlc_device *hdlc = dev_to_hdlc(dev);
146#ifdef DEBUG_LINK
147 printk(KERN_DEBUG "%s: hdlc_open() carrier %i open %i\n", dev->name,
148 hdlc->carrier, hdlc->open);
149#endif
150
151 if (!hdlc->proto)
152 return -ENOSYS; /* no protocol attached */
153
154 if (hdlc->proto->open) {
155 int result = hdlc->proto->open(dev);
156
157 if (result)
158 return result;
159 }
160
161 spin_lock_irq(&hdlc->state_lock);
162
163 if (hdlc->carrier) {
164 netdev_info(dev, "Carrier detected\n");
165 hdlc_proto_start(dev);
166 } else {
167 netdev_info(dev, "No carrier\n");
168 }
169
170 hdlc->open = 1;
171
172 spin_unlock_irq(&hdlc->state_lock);
173 return 0;
174}
175EXPORT_SYMBOL(hdlc_open);
176
177/* Must be called by hardware driver when HDLC device is being closed */
178void hdlc_close(struct net_device *dev)
179{
180 hdlc_device *hdlc = dev_to_hdlc(dev);
181#ifdef DEBUG_LINK
182 printk(KERN_DEBUG "%s: hdlc_close() carrier %i open %i\n", dev->name,
183 hdlc->carrier, hdlc->open);
184#endif
185
186 spin_lock_irq(&hdlc->state_lock);
187
188 hdlc->open = 0;
189 if (hdlc->carrier)
190 hdlc_proto_stop(dev);
191
192 spin_unlock_irq(&hdlc->state_lock);
193
194 if (hdlc->proto->close)
195 hdlc->proto->close(dev);
196}
197EXPORT_SYMBOL(hdlc_close);
198
199int hdlc_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
200{
201 struct hdlc_proto *proto = first_proto;
202 int result;
203
204 if (cmd != SIOCWANDEV)
205 return -EINVAL;
206
207 if (dev_to_hdlc(dev)->proto) {
208 result = dev_to_hdlc(dev)->proto->ioctl(dev, ifr);
209 if (result != -EINVAL)
210 return result;
211 }
212
213 /* Not handled by currently attached protocol (if any) */
214
215 while (proto) {
216 result = proto->ioctl(dev, ifr);
217 if (result != -EINVAL)
218 return result;
219 proto = proto->next;
220 }
221 return -EINVAL;
222}
223EXPORT_SYMBOL(hdlc_ioctl);
224
225static const struct header_ops hdlc_null_ops;
226
227static void hdlc_setup_dev(struct net_device *dev)
228{
229 /* Re-init all variables changed by HDLC protocol drivers,
230 * including ether_setup() called from hdlc_raw_eth.c.
231 */
232 dev->flags = IFF_POINTOPOINT | IFF_NOARP;
233 dev->priv_flags = IFF_WAN_HDLC;
234 dev->mtu = HDLC_MAX_MTU;
235 dev->min_mtu = 68;
236 dev->max_mtu = HDLC_MAX_MTU;
237 dev->type = ARPHRD_RAWHDLC;
238 dev->hard_header_len = 0;
239 dev->needed_headroom = 0;
240 dev->addr_len = 0;
241 dev->header_ops = &hdlc_null_ops;
242}
243
244static void hdlc_setup(struct net_device *dev)
245{
246 hdlc_device *hdlc = dev_to_hdlc(dev);
247
248 hdlc_setup_dev(dev);
249 hdlc->carrier = 1;
250 hdlc->open = 0;
251 spin_lock_init(&hdlc->state_lock);
252}
253
254struct net_device *alloc_hdlcdev(void *priv)
255{
256 struct net_device *dev;
257
258 dev = alloc_netdev(sizeof(struct hdlc_device), "hdlc%d",
259 NET_NAME_UNKNOWN, hdlc_setup);
260 if (dev)
261 dev_to_hdlc(dev)->priv = priv;
262 return dev;
263}
264EXPORT_SYMBOL(alloc_hdlcdev);
265
266void unregister_hdlc_device(struct net_device *dev)
267{
268 rtnl_lock();
269 detach_hdlc_protocol(dev);
270 unregister_netdevice(dev);
271 rtnl_unlock();
272}
273EXPORT_SYMBOL(unregister_hdlc_device);
274
275int attach_hdlc_protocol(struct net_device *dev, struct hdlc_proto *proto,
276 size_t size)
277{
278 int err;
279
280 err = detach_hdlc_protocol(dev);
281 if (err)
282 return err;
283
284 if (!try_module_get(proto->module))
285 return -ENOSYS;
286
287 if (size) {
288 dev_to_hdlc(dev)->state = kmalloc(size, GFP_KERNEL);
289 if (!dev_to_hdlc(dev)->state) {
290 module_put(proto->module);
291 return -ENOBUFS;
292 }
293 }
294 dev_to_hdlc(dev)->proto = proto;
295
296 return 0;
297}
298EXPORT_SYMBOL(attach_hdlc_protocol);
299
300int detach_hdlc_protocol(struct net_device *dev)
301{
302 hdlc_device *hdlc = dev_to_hdlc(dev);
303 int err;
304
305 if (hdlc->proto) {
306 err = call_netdevice_notifiers(NETDEV_PRE_TYPE_CHANGE, dev);
307 err = notifier_to_errno(err);
308 if (err) {
309 netdev_err(dev, "Refused to change device type\n");
310 return err;
311 }
312
313 if (hdlc->proto->detach)
314 hdlc->proto->detach(dev);
315 module_put(hdlc->proto->module);
316 hdlc->proto = NULL;
317 }
318 kfree(hdlc->state);
319 hdlc->state = NULL;
320 hdlc_setup_dev(dev);
321
322 return 0;
323}
324EXPORT_SYMBOL(detach_hdlc_protocol);
325
326void register_hdlc_protocol(struct hdlc_proto *proto)
327{
328 rtnl_lock();
329 proto->next = first_proto;
330 first_proto = proto;
331 rtnl_unlock();
332}
333EXPORT_SYMBOL(register_hdlc_protocol);
334
335void unregister_hdlc_protocol(struct hdlc_proto *proto)
336{
337 struct hdlc_proto **p;
338
339 rtnl_lock();
340 p = &first_proto;
341 while (*p != proto) {
342 BUG_ON(!*p);
343 p = &((*p)->next);
344 }
345 *p = proto->next;
346 rtnl_unlock();
347}
348EXPORT_SYMBOL(unregister_hdlc_protocol);
349
350MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
351MODULE_DESCRIPTION("HDLC support module");
352MODULE_LICENSE("GPL v2");
353
354static struct packet_type hdlc_packet_type __read_mostly = {
355 .type = cpu_to_be16(ETH_P_HDLC),
356 .func = hdlc_rcv,
357};
358
359static struct notifier_block hdlc_notifier = {
360 .notifier_call = hdlc_device_event,
361};
362
363static int __init hdlc_module_init(void)
364{
365 int result;
366
367 pr_info("%s\n", version);
368 result = register_netdevice_notifier(&hdlc_notifier);
369 if (result)
370 return result;
371 dev_add_pack(&hdlc_packet_type);
372 return 0;
373}
374
375static void __exit hdlc_module_exit(void)
376{
377 dev_remove_pack(&hdlc_packet_type);
378 unregister_netdevice_notifier(&hdlc_notifier);
379}
380
381module_init(hdlc_module_init);
382module_exit(hdlc_module_exit);