Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
[linux-2.6] / drivers / net / wan / hdlc.c
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
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
57 static struct net_device_stats *hdlc_get_stats(struct net_device *dev)
58 {
59         return &dev->stats;
60 }
61
62
63
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
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
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
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 */
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 */
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
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
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
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
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
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
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
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
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
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
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
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);