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