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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/*
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 = 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 if ((dev_to_hdlc(dev)->state = kmalloc(size,
285 GFP_KERNEL)) == NULL) {
286 netdev_warn(dev,
287 "Memory squeeze on hdlc_proto_attach()\n");
288 module_put(proto->module);
289 return -ENOBUFS;
290 }
291 dev_to_hdlc(dev)->proto = proto;
292 return 0;
293}
294
295
296void detach_hdlc_protocol(struct net_device *dev)
297{
298 hdlc_device *hdlc = dev_to_hdlc(dev);
299
300 if (hdlc->proto) {
301 if (hdlc->proto->detach)
302 hdlc->proto->detach(dev);
303 module_put(hdlc->proto->module);
304 hdlc->proto = NULL;
305 }
306 kfree(hdlc->state);
307 hdlc->state = NULL;
308 hdlc_setup_dev(dev);
309}
310
311
312void register_hdlc_protocol(struct hdlc_proto *proto)
313{
314 rtnl_lock();
315 proto->next = first_proto;
316 first_proto = proto;
317 rtnl_unlock();
318}
319
320
321void unregister_hdlc_protocol(struct hdlc_proto *proto)
322{
323 struct hdlc_proto **p;
324
325 rtnl_lock();
326 p = &first_proto;
327 while (*p != proto) {
328 BUG_ON(!*p);
329 p = &((*p)->next);
330 }
331 *p = proto->next;
332 rtnl_unlock();
333}
334
335
336
337MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
338MODULE_DESCRIPTION("HDLC support module");
339MODULE_LICENSE("GPL v2");
340
341EXPORT_SYMBOL(hdlc_change_mtu);
342EXPORT_SYMBOL(hdlc_start_xmit);
343EXPORT_SYMBOL(hdlc_open);
344EXPORT_SYMBOL(hdlc_close);
345EXPORT_SYMBOL(hdlc_ioctl);
346EXPORT_SYMBOL(alloc_hdlcdev);
347EXPORT_SYMBOL(unregister_hdlc_device);
348EXPORT_SYMBOL(register_hdlc_protocol);
349EXPORT_SYMBOL(unregister_hdlc_protocol);
350EXPORT_SYMBOL(attach_hdlc_protocol);
351EXPORT_SYMBOL(detach_hdlc_protocol);
352
353static struct packet_type hdlc_packet_type __read_mostly = {
354 .type = cpu_to_be16(ETH_P_HDLC),
355 .func = hdlc_rcv,
356};
357
358
359static struct notifier_block hdlc_notifier = {
360 .notifier_call = hdlc_device_event,
361};
362
363
364static int __init hdlc_module_init(void)
365{
366 int result;
367
368 pr_info("%s\n", version);
369 if ((result = register_netdevice_notifier(&hdlc_notifier)) != 0)
370 return result;
371 dev_add_pack(&hdlc_packet_type);
372 return 0;
373}
374
375
376
377static void __exit hdlc_module_exit(void)
378{
379 dev_remove_pack(&hdlc_packet_type);
380 unregister_netdevice_notifier(&hdlc_notifier);
381}
382
383
384module_init(hdlc_module_init);
385module_exit(hdlc_module_exit);