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