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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);
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;
101
102 if (event != NETDEV_CHANGE)
103 return NOTIFY_DONE;
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;
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
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;
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
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
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
224
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);
392
