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