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 #define pr_fmt(fmt) "X25: " fmt
25
26 #include <linux/kernel.h>
27 #include <linux/jiffies.h>
28 #include <linux/timer.h>
29 #include <linux/slab.h>
30 #include <linux/netdevice.h>
31 #include <linux/skbuff.h>
32 #include <linux/uaccess.h>
33 #include <linux/init.h>
34 #include <net/x25.h>
35
36 LIST_HEAD(x25_neigh_list);
37 DEFINE_RWLOCK(x25_neigh_list_lock);
38
39 static void x25_t20timer_expiry(struct timer_list *);
40
41 static void x25_transmit_restart_confirmation(struct x25_neigh *nb);
42 static void x25_transmit_restart_request(struct x25_neigh *nb);
43
44 /*
45 * Linux set/reset timer routines
46 */
x25_start_t20timer(struct x25_neigh * nb)47 static inline void x25_start_t20timer(struct x25_neigh *nb)
48 {
49 mod_timer(&nb->t20timer, jiffies + nb->t20);
50 }
51
x25_t20timer_expiry(struct timer_list * t)52 static void x25_t20timer_expiry(struct timer_list *t)
53 {
54 struct x25_neigh *nb = from_timer(nb, t, t20timer);
55
56 x25_transmit_restart_request(nb);
57
58 x25_start_t20timer(nb);
59 }
60
x25_stop_t20timer(struct x25_neigh * nb)61 static inline void x25_stop_t20timer(struct x25_neigh *nb)
62 {
63 del_timer(&nb->t20timer);
64 }
65
x25_t20timer_pending(struct x25_neigh * nb)66 static inline int x25_t20timer_pending(struct x25_neigh *nb)
67 {
68 return timer_pending(&nb->t20timer);
69 }
70
71 /*
72 * This handles all restart and diagnostic frames.
73 */
x25_link_control(struct sk_buff * skb,struct x25_neigh * nb,unsigned short frametype)74 void x25_link_control(struct sk_buff *skb, struct x25_neigh *nb,
75 unsigned short frametype)
76 {
77 struct sk_buff *skbn;
78 int confirm;
79
80 switch (frametype) {
81 case X25_RESTART_REQUEST:
82 confirm = !x25_t20timer_pending(nb);
83 x25_stop_t20timer(nb);
84 nb->state = X25_LINK_STATE_3;
85 if (confirm)
86 x25_transmit_restart_confirmation(nb);
87 break;
88
89 case X25_RESTART_CONFIRMATION:
90 x25_stop_t20timer(nb);
91 nb->state = X25_LINK_STATE_3;
92 break;
93
94 case X25_DIAGNOSTIC:
95 if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 4))
96 break;
97
98 pr_warn("diagnostic #%d - %02X %02X %02X\n",
99 skb->data[3], skb->data[4],
100 skb->data[5], skb->data[6]);
101 break;
102
103 default:
104 pr_warn("received unknown %02X with LCI 000\n",
105 frametype);
106 break;
107 }
108
109 if (nb->state == X25_LINK_STATE_3)
110 while ((skbn = skb_dequeue(&nb->queue)) != NULL)
111 x25_send_frame(skbn, nb);
112 }
113
114 /*
115 * This routine is called when a Restart Request is needed
116 */
x25_transmit_restart_request(struct x25_neigh * nb)117 static void x25_transmit_restart_request(struct x25_neigh *nb)
118 {
119 unsigned char *dptr;
120 int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN + 2;
121 struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
122
123 if (!skb)
124 return;
125
126 skb_reserve(skb, X25_MAX_L2_LEN);
127
128 dptr = skb_put(skb, X25_STD_MIN_LEN + 2);
129
130 *dptr++ = nb->extended ? X25_GFI_EXTSEQ : X25_GFI_STDSEQ;
131 *dptr++ = 0x00;
132 *dptr++ = X25_RESTART_REQUEST;
133 *dptr++ = 0x00;
134 *dptr++ = 0;
135
136 skb->sk = NULL;
137
138 x25_send_frame(skb, nb);
139 }
140
141 /*
142 * This routine is called when a Restart Confirmation is needed
143 */
x25_transmit_restart_confirmation(struct x25_neigh * nb)144 static void x25_transmit_restart_confirmation(struct x25_neigh *nb)
145 {
146 unsigned char *dptr;
147 int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN;
148 struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
149
150 if (!skb)
151 return;
152
153 skb_reserve(skb, X25_MAX_L2_LEN);
154
155 dptr = skb_put(skb, X25_STD_MIN_LEN);
156
157 *dptr++ = nb->extended ? X25_GFI_EXTSEQ : X25_GFI_STDSEQ;
158 *dptr++ = 0x00;
159 *dptr++ = X25_RESTART_CONFIRMATION;
160
161 skb->sk = NULL;
162
163 x25_send_frame(skb, nb);
164 }
165
166 /*
167 * This routine is called when a Clear Request is needed outside of the context
168 * of a connected socket.
169 */
x25_transmit_clear_request(struct x25_neigh * nb,unsigned int lci,unsigned char cause)170 void x25_transmit_clear_request(struct x25_neigh *nb, unsigned int lci,
171 unsigned char cause)
172 {
173 unsigned char *dptr;
174 int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN + 2;
175 struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
176
177 if (!skb)
178 return;
179
180 skb_reserve(skb, X25_MAX_L2_LEN);
181
182 dptr = skb_put(skb, X25_STD_MIN_LEN + 2);
183
184 *dptr++ = ((lci >> 8) & 0x0F) | (nb->extended ?
185 X25_GFI_EXTSEQ :
186 X25_GFI_STDSEQ);
187 *dptr++ = (lci >> 0) & 0xFF;
188 *dptr++ = X25_CLEAR_REQUEST;
189 *dptr++ = cause;
190 *dptr++ = 0x00;
191
192 skb->sk = NULL;
193
194 x25_send_frame(skb, nb);
195 }
196
x25_transmit_link(struct sk_buff * skb,struct x25_neigh * nb)197 void x25_transmit_link(struct sk_buff *skb, struct x25_neigh *nb)
198 {
199 switch (nb->state) {
200 case X25_LINK_STATE_0:
201 skb_queue_tail(&nb->queue, skb);
202 nb->state = X25_LINK_STATE_1;
203 x25_establish_link(nb);
204 break;
205 case X25_LINK_STATE_1:
206 case X25_LINK_STATE_2:
207 skb_queue_tail(&nb->queue, skb);
208 break;
209 case X25_LINK_STATE_3:
210 x25_send_frame(skb, nb);
211 break;
212 }
213 }
214
215 /*
216 * Called when the link layer has become established.
217 */
x25_link_established(struct x25_neigh * nb)218 void x25_link_established(struct x25_neigh *nb)
219 {
220 switch (nb->state) {
221 case X25_LINK_STATE_0:
222 nb->state = X25_LINK_STATE_2;
223 break;
224 case X25_LINK_STATE_1:
225 x25_transmit_restart_request(nb);
226 nb->state = X25_LINK_STATE_2;
227 x25_start_t20timer(nb);
228 break;
229 }
230 }
231
232 /*
233 * Called when the link layer has terminated, or an establishment
234 * request has failed.
235 */
236
x25_link_terminated(struct x25_neigh * nb)237 void x25_link_terminated(struct x25_neigh *nb)
238 {
239 nb->state = X25_LINK_STATE_0;
240 /* Out of order: clear existing virtual calls (X.25 03/93 4.6.3) */
241 x25_kill_by_neigh(nb);
242 }
243
244 /*
245 * Add a new device.
246 */
x25_link_device_up(struct net_device * dev)247 void x25_link_device_up(struct net_device *dev)
248 {
249 struct x25_neigh *nb = kmalloc(sizeof(*nb), GFP_ATOMIC);
250
251 if (!nb)
252 return;
253
254 skb_queue_head_init(&nb->queue);
255 timer_setup(&nb->t20timer, x25_t20timer_expiry, 0);
256
257 dev_hold(dev);
258 nb->dev = dev;
259 nb->state = X25_LINK_STATE_0;
260 nb->extended = 0;
261 /*
262 * Enables negotiation
263 */
264 nb->global_facil_mask = X25_MASK_REVERSE |
265 X25_MASK_THROUGHPUT |
266 X25_MASK_PACKET_SIZE |
267 X25_MASK_WINDOW_SIZE;
268 nb->t20 = sysctl_x25_restart_request_timeout;
269 refcount_set(&nb->refcnt, 1);
270
271 write_lock_bh(&x25_neigh_list_lock);
272 list_add(&nb->node, &x25_neigh_list);
273 write_unlock_bh(&x25_neigh_list_lock);
274 }
275
276 /**
277 * __x25_remove_neigh - remove neighbour from x25_neigh_list
278 * @nb - neigh to remove
279 *
280 * Remove neighbour from x25_neigh_list. If it was there.
281 * Caller must hold x25_neigh_list_lock.
282 */
__x25_remove_neigh(struct x25_neigh * nb)283 static void __x25_remove_neigh(struct x25_neigh *nb)
284 {
285 skb_queue_purge(&nb->queue);
286 x25_stop_t20timer(nb);
287
288 if (nb->node.next) {
289 list_del(&nb->node);
290 x25_neigh_put(nb);
291 }
292 }
293
294 /*
295 * A device has been removed, remove its links.
296 */
x25_link_device_down(struct net_device * dev)297 void x25_link_device_down(struct net_device *dev)
298 {
299 struct x25_neigh *nb;
300 struct list_head *entry, *tmp;
301
302 write_lock_bh(&x25_neigh_list_lock);
303
304 list_for_each_safe(entry, tmp, &x25_neigh_list) {
305 nb = list_entry(entry, struct x25_neigh, node);
306
307 if (nb->dev == dev) {
308 __x25_remove_neigh(nb);
309 dev_put(dev);
310 }
311 }
312
313 write_unlock_bh(&x25_neigh_list_lock);
314 }
315
316 /*
317 * Given a device, return the neighbour address.
318 */
x25_get_neigh(struct net_device * dev)319 struct x25_neigh *x25_get_neigh(struct net_device *dev)
320 {
321 struct x25_neigh *nb, *use = NULL;
322 struct list_head *entry;
323
324 read_lock_bh(&x25_neigh_list_lock);
325 list_for_each(entry, &x25_neigh_list) {
326 nb = list_entry(entry, struct x25_neigh, node);
327
328 if (nb->dev == dev) {
329 use = nb;
330 break;
331 }
332 }
333
334 if (use)
335 x25_neigh_hold(use);
336 read_unlock_bh(&x25_neigh_list_lock);
337 return use;
338 }
339
340 /*
341 * Handle the ioctls that control the subscription functions.
342 */
x25_subscr_ioctl(unsigned int cmd,void __user * arg)343 int x25_subscr_ioctl(unsigned int cmd, void __user *arg)
344 {
345 struct x25_subscrip_struct x25_subscr;
346 struct x25_neigh *nb;
347 struct net_device *dev;
348 int rc = -EINVAL;
349
350 if (cmd != SIOCX25GSUBSCRIP && cmd != SIOCX25SSUBSCRIP)
351 goto out;
352
353 rc = -EFAULT;
354 if (copy_from_user(&x25_subscr, arg, sizeof(x25_subscr)))
355 goto out;
356
357 rc = -EINVAL;
358 if ((dev = x25_dev_get(x25_subscr.device)) == NULL)
359 goto out;
360
361 if ((nb = x25_get_neigh(dev)) == NULL)
362 goto out_dev_put;
363
364 dev_put(dev);
365
366 if (cmd == SIOCX25GSUBSCRIP) {
367 read_lock_bh(&x25_neigh_list_lock);
368 x25_subscr.extended = nb->extended;
369 x25_subscr.global_facil_mask = nb->global_facil_mask;
370 read_unlock_bh(&x25_neigh_list_lock);
371 rc = copy_to_user(arg, &x25_subscr,
372 sizeof(x25_subscr)) ? -EFAULT : 0;
373 } else {
374 rc = -EINVAL;
375 if (!(x25_subscr.extended && x25_subscr.extended != 1)) {
376 rc = 0;
377 write_lock_bh(&x25_neigh_list_lock);
378 nb->extended = x25_subscr.extended;
379 nb->global_facil_mask = x25_subscr.global_facil_mask;
380 write_unlock_bh(&x25_neigh_list_lock);
381 }
382 }
383 x25_neigh_put(nb);
384 out:
385 return rc;
386 out_dev_put:
387 dev_put(dev);
388 goto out;
389 }
390
391
392 /*
393 * Release all memory associated with X.25 neighbour structures.
394 */
x25_link_free(void)395 void __exit x25_link_free(void)
396 {
397 struct x25_neigh *nb;
398 struct list_head *entry, *tmp;
399
400 write_lock_bh(&x25_neigh_list_lock);
401
402 list_for_each_safe(entry, tmp, &x25_neigh_list) {
403 struct net_device *dev;
404
405 nb = list_entry(entry, struct x25_neigh, node);
406 dev = nb->dev;
407 __x25_remove_neigh(nb);
408 dev_put(dev);
409 }
410 write_unlock_bh(&x25_neigh_list_lock);
411 }
412
