1 /*
2 * X.25 Packet Layer release 002
3 *
4 * This is ALPHA test software. This code may break your machine,
5 * randomly fail to work with new releases, misbehave and/or generally
6 * screw up. It might even work.
7 *
8 * This code REQUIRES 2.1.15 or higher
9 *
10 * This module:
11 * This module is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License
13 * as published by the Free Software Foundation; either version
14 * 2 of the License, or (at your option) any later version.
15 *
16 * History
17 * X.25 001 Jonathan Naylor Started coding.
18 * X.25 002 Jonathan Naylor New timer architecture.
19 * mar/20/00 Daniela Squassoni Disabling/enabling of facilities
20 * negotiation.
21 * 2000-09-04 Henner Eisen dev_hold() / dev_put() for x25_neigh.
22 */
23
24 #include <linux/kernel.h>
25 #include <linux/jiffies.h>
26 #include <linux/timer.h>
27 #include <linux/slab.h>
28 #include <linux/netdevice.h>
29 #include <linux/skbuff.h>
30 #include <asm/uaccess.h>
31 #include <linux/init.h>
32 #include <net/x25.h>
33
34 LIST_HEAD(x25_neigh_list);
35 DEFINE_RWLOCK(x25_neigh_list_lock);
36
37 static void x25_t20timer_expiry(unsigned long);
38
39 static void x25_transmit_restart_confirmation(struct x25_neigh *nb);
40 static void x25_transmit_restart_request(struct x25_neigh *nb);
41
42 /*
43 * Linux set/reset timer routines
44 */
x25_start_t20timer(struct x25_neigh * nb)45 static inline void x25_start_t20timer(struct x25_neigh *nb)
46 {
47 mod_timer(&nb->t20timer, jiffies + nb->t20);
48 }
49
x25_t20timer_expiry(unsigned long param)50 static void x25_t20timer_expiry(unsigned long param)
51 {
52 struct x25_neigh *nb = (struct x25_neigh *)param;
53
54 x25_transmit_restart_request(nb);
55
56 x25_start_t20timer(nb);
57 }
58
x25_stop_t20timer(struct x25_neigh * nb)59 static inline void x25_stop_t20timer(struct x25_neigh *nb)
60 {
61 del_timer(&nb->t20timer);
62 }
63
x25_t20timer_pending(struct x25_neigh * nb)64 static inline int x25_t20timer_pending(struct x25_neigh *nb)
65 {
66 return timer_pending(&nb->t20timer);
67 }
68
69 /*
70 * This handles all restart and diagnostic frames.
71 */
x25_link_control(struct sk_buff * skb,struct x25_neigh * nb,unsigned short frametype)72 void x25_link_control(struct sk_buff *skb, struct x25_neigh *nb,
73 unsigned short frametype)
74 {
75 struct sk_buff *skbn;
76 int confirm;
77
78 switch (frametype) {
79 case X25_RESTART_REQUEST:
80 confirm = !x25_t20timer_pending(nb);
81 x25_stop_t20timer(nb);
82 nb->state = X25_LINK_STATE_3;
83 if (confirm)
84 x25_transmit_restart_confirmation(nb);
85 break;
86
87 case X25_RESTART_CONFIRMATION:
88 x25_stop_t20timer(nb);
89 nb->state = X25_LINK_STATE_3;
90 break;
91
92 case X25_DIAGNOSTIC:
93 if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 4))
94 break;
95
96 printk(KERN_WARNING "x25: diagnostic #%d - %02X %02X %02X\n",
97 skb->data[3], skb->data[4],
98 skb->data[5], skb->data[6]);
99 break;
100
101 default:
102 printk(KERN_WARNING "x25: received unknown %02X with LCI 000\n",
103 frametype);
104 break;
105 }
106
107 if (nb->state == X25_LINK_STATE_3)
108 while ((skbn = skb_dequeue(&nb->queue)) != NULL)
109 x25_send_frame(skbn, nb);
110 }
111
112 /*
113 * This routine is called when a Restart Request is needed
114 */
x25_transmit_restart_request(struct x25_neigh * nb)115 static void x25_transmit_restart_request(struct x25_neigh *nb)
116 {
117 unsigned char *dptr;
118 int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN + 2;
119 struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
120
121 if (!skb)
122 return;
123
124 skb_reserve(skb, X25_MAX_L2_LEN);
125
126 dptr = skb_put(skb, X25_STD_MIN_LEN + 2);
127
128 *dptr++ = nb->extended ? X25_GFI_EXTSEQ : X25_GFI_STDSEQ;
129 *dptr++ = 0x00;
130 *dptr++ = X25_RESTART_REQUEST;
131 *dptr++ = 0x00;
132 *dptr++ = 0;
133
134 skb->sk = NULL;
135
136 x25_send_frame(skb, nb);
137 }
138
139 /*
140 * This routine is called when a Restart Confirmation is needed
141 */
x25_transmit_restart_confirmation(struct x25_neigh * nb)142 static void x25_transmit_restart_confirmation(struct x25_neigh *nb)
143 {
144 unsigned char *dptr;
145 int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN;
146 struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
147
148 if (!skb)
149 return;
150
151 skb_reserve(skb, X25_MAX_L2_LEN);
152
153 dptr = skb_put(skb, X25_STD_MIN_LEN);
154
155 *dptr++ = nb->extended ? X25_GFI_EXTSEQ : X25_GFI_STDSEQ;
156 *dptr++ = 0x00;
157 *dptr++ = X25_RESTART_CONFIRMATION;
158
159 skb->sk = NULL;
160
161 x25_send_frame(skb, nb);
162 }
163
164 /*
165 * This routine is called when a Clear Request is needed outside of the context
166 * of a connected socket.
167 */
x25_transmit_clear_request(struct x25_neigh * nb,unsigned int lci,unsigned char cause)168 void x25_transmit_clear_request(struct x25_neigh *nb, unsigned int lci,
169 unsigned char cause)
170 {
171 unsigned char *dptr;
172 int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN + 2;
173 struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
174
175 if (!skb)
176 return;
177
178 skb_reserve(skb, X25_MAX_L2_LEN);
179
180 dptr = skb_put(skb, X25_STD_MIN_LEN + 2);
181
182 *dptr++ = ((lci >> 8) & 0x0F) | (nb->extended ?
183 X25_GFI_EXTSEQ :
184 X25_GFI_STDSEQ);
185 *dptr++ = (lci >> 0) & 0xFF;
186 *dptr++ = X25_CLEAR_REQUEST;
187 *dptr++ = cause;
188 *dptr++ = 0x00;
189
190 skb->sk = NULL;
191
192 x25_send_frame(skb, nb);
193 }
194
x25_transmit_link(struct sk_buff * skb,struct x25_neigh * nb)195 void x25_transmit_link(struct sk_buff *skb, struct x25_neigh *nb)
196 {
197 switch (nb->state) {
198 case X25_LINK_STATE_0:
199 skb_queue_tail(&nb->queue, skb);
200 nb->state = X25_LINK_STATE_1;
201 x25_establish_link(nb);
202 break;
203 case X25_LINK_STATE_1:
204 case X25_LINK_STATE_2:
205 skb_queue_tail(&nb->queue, skb);
206 break;
207 case X25_LINK_STATE_3:
208 x25_send_frame(skb, nb);
209 break;
210 }
211 }
212
213 /*
214 * Called when the link layer has become established.
215 */
x25_link_established(struct x25_neigh * nb)216 void x25_link_established(struct x25_neigh *nb)
217 {
218 switch (nb->state) {
219 case X25_LINK_STATE_0:
220 nb->state = X25_LINK_STATE_2;
221 break;
222 case X25_LINK_STATE_1:
223 x25_transmit_restart_request(nb);
224 nb->state = X25_LINK_STATE_2;
225 x25_start_t20timer(nb);
226 break;
227 }
228 }
229
230 /*
231 * Called when the link layer has terminated, or an establishment
232 * request has failed.
233 */
234
x25_link_terminated(struct x25_neigh * nb)235 void x25_link_terminated(struct x25_neigh *nb)
236 {
237 nb->state = X25_LINK_STATE_0;
238 /* Out of order: clear existing virtual calls (X.25 03/93 4.6.3) */
239 x25_kill_by_neigh(nb);
240 }
241
242 /*
243 * Add a new device.
244 */
x25_link_device_up(struct net_device * dev)245 void x25_link_device_up(struct net_device *dev)
246 {
247 struct x25_neigh *nb = kmalloc(sizeof(*nb), GFP_ATOMIC);
248
249 if (!nb)
250 return;
251
252 skb_queue_head_init(&nb->queue);
253 setup_timer(&nb->t20timer, x25_t20timer_expiry, (unsigned long)nb);
254
255 dev_hold(dev);
256 nb->dev = dev;
257 nb->state = X25_LINK_STATE_0;
258 nb->extended = 0;
259 /*
260 * Enables negotiation
261 */
262 nb->global_facil_mask = X25_MASK_REVERSE |
263 X25_MASK_THROUGHPUT |
264 X25_MASK_PACKET_SIZE |
265 X25_MASK_WINDOW_SIZE;
266 nb->t20 = sysctl_x25_restart_request_timeout;
267 atomic_set(&nb->refcnt, 1);
268
269 write_lock_bh(&x25_neigh_list_lock);
270 list_add(&nb->node, &x25_neigh_list);
271 write_unlock_bh(&x25_neigh_list_lock);
272 }
273
274 /**
275 * __x25_remove_neigh - remove neighbour from x25_neigh_list
276 * @nb - neigh to remove
277 *
278 * Remove neighbour from x25_neigh_list. If it was there.
279 * Caller must hold x25_neigh_list_lock.
280 */
__x25_remove_neigh(struct x25_neigh * nb)281 static void __x25_remove_neigh(struct x25_neigh *nb)
282 {
283 skb_queue_purge(&nb->queue);
284 x25_stop_t20timer(nb);
285
286 if (nb->node.next) {
287 list_del(&nb->node);
288 x25_neigh_put(nb);
289 }
290 }
291
292 /*
293 * A device has been removed, remove its links.
294 */
x25_link_device_down(struct net_device * dev)295 void x25_link_device_down(struct net_device *dev)
296 {
297 struct x25_neigh *nb;
298 struct list_head *entry, *tmp;
299
300 write_lock_bh(&x25_neigh_list_lock);
301
302 list_for_each_safe(entry, tmp, &x25_neigh_list) {
303 nb = list_entry(entry, struct x25_neigh, node);
304
305 if (nb->dev == dev) {
306 __x25_remove_neigh(nb);
307 dev_put(dev);
308 }
309 }
310
311 write_unlock_bh(&x25_neigh_list_lock);
312 }
313
314 /*
315 * Given a device, return the neighbour address.
316 */
x25_get_neigh(struct net_device * dev)317 struct x25_neigh *x25_get_neigh(struct net_device *dev)
318 {
319 struct x25_neigh *nb, *use = NULL;
320 struct list_head *entry;
321
322 read_lock_bh(&x25_neigh_list_lock);
323 list_for_each(entry, &x25_neigh_list) {
324 nb = list_entry(entry, struct x25_neigh, node);
325
326 if (nb->dev == dev) {
327 use = nb;
328 break;
329 }
330 }
331
332 if (use)
333 x25_neigh_hold(use);
334 read_unlock_bh(&x25_neigh_list_lock);
335 return use;
336 }
337
338 /*
339 * Handle the ioctls that control the subscription functions.
340 */
x25_subscr_ioctl(unsigned int cmd,void __user * arg)341 int x25_subscr_ioctl(unsigned int cmd, void __user *arg)
342 {
343 struct x25_subscrip_struct x25_subscr;
344 struct x25_neigh *nb;
345 struct net_device *dev;
346 int rc = -EINVAL;
347
348 if (cmd != SIOCX25GSUBSCRIP && cmd != SIOCX25SSUBSCRIP)
349 goto out;
350
351 rc = -EFAULT;
352 if (copy_from_user(&x25_subscr, arg, sizeof(x25_subscr)))
353 goto out;
354
355 rc = -EINVAL;
356 if ((dev = x25_dev_get(x25_subscr.device)) == NULL)
357 goto out;
358
359 if ((nb = x25_get_neigh(dev)) == NULL)
360 goto out_dev_put;
361
362 dev_put(dev);
363
364 if (cmd == SIOCX25GSUBSCRIP) {
365 read_lock_bh(&x25_neigh_list_lock);
366 x25_subscr.extended = nb->extended;
367 x25_subscr.global_facil_mask = nb->global_facil_mask;
368 read_unlock_bh(&x25_neigh_list_lock);
369 rc = copy_to_user(arg, &x25_subscr,
370 sizeof(x25_subscr)) ? -EFAULT : 0;
371 } else {
372 rc = -EINVAL;
373 if (!(x25_subscr.extended && x25_subscr.extended != 1)) {
374 rc = 0;
375 write_lock_bh(&x25_neigh_list_lock);
376 nb->extended = x25_subscr.extended;
377 nb->global_facil_mask = x25_subscr.global_facil_mask;
378 write_unlock_bh(&x25_neigh_list_lock);
379 }
380 }
381 x25_neigh_put(nb);
382 out:
383 return rc;
384 out_dev_put:
385 dev_put(dev);
386 goto out;
387 }
388
389
390 /*
391 * Release all memory associated with X.25 neighbour structures.
392 */
x25_link_free(void)393 void __exit x25_link_free(void)
394 {
395 struct x25_neigh *nb;
396 struct list_head *entry, *tmp;
397
398 write_lock_bh(&x25_neigh_list_lock);
399
400 list_for_each_safe(entry, tmp, &x25_neigh_list) {
401 struct net_device *dev;
402
403 nb = list_entry(entry, struct x25_neigh, node);
404 dev = nb->dev;
405 __x25_remove_neigh(nb);
406 dev_put(dev);
407 }
408 write_unlock_bh(&x25_neigh_list_lock);
409 }
410