[PATCH] Add retain_initrd boot option
[linux-2.6.git] / net / x25 / x25_link.c
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/netdevice.h>
28 #include <linux/skbuff.h>
29 #include <asm/uaccess.h>
30 #include <linux/init.h>
31 #include <net/x25.h>
32
33 static struct list_head x25_neigh_list = LIST_HEAD_INIT(x25_neigh_list);
34 static DEFINE_RWLOCK(x25_neigh_list_lock);
35
36 static void x25_t20timer_expiry(unsigned long);
37
38 static void x25_transmit_restart_confirmation(struct x25_neigh *nb);
39 static void x25_transmit_restart_request(struct x25_neigh *nb);
40
41 /*
42  *      Linux set/reset timer routines
43  */
44 static inline void x25_start_t20timer(struct x25_neigh *nb)
45 {
46         mod_timer(&nb->t20timer, jiffies + nb->t20);
47 }
48
49 static void x25_t20timer_expiry(unsigned long param)
50 {
51         struct x25_neigh *nb = (struct x25_neigh *)param;
52
53         x25_transmit_restart_request(nb);
54
55         x25_start_t20timer(nb);
56 }
57
58 static inline void x25_stop_t20timer(struct x25_neigh *nb)
59 {
60         del_timer(&nb->t20timer);
61 }
62
63 static inline int x25_t20timer_pending(struct x25_neigh *nb)
64 {
65         return timer_pending(&nb->t20timer);
66 }
67
68 /*
69  *      This handles all restart and diagnostic frames.
70  */
71 void x25_link_control(struct sk_buff *skb, struct x25_neigh *nb,
72                       unsigned short frametype)
73 {
74         struct sk_buff *skbn;
75         int confirm;
76
77         switch (frametype) {
78                 case X25_RESTART_REQUEST:
79                         confirm = !x25_t20timer_pending(nb);
80                         x25_stop_t20timer(nb);
81                         nb->state = X25_LINK_STATE_3;
82                         if (confirm)
83                                 x25_transmit_restart_confirmation(nb);
84                         break;
85
86                 case X25_RESTART_CONFIRMATION:
87                         x25_stop_t20timer(nb);
88                         nb->state = X25_LINK_STATE_3;
89                         break;
90
91                 case X25_DIAGNOSTIC:
92                         printk(KERN_WARNING "x25: diagnostic #%d - "
93                                "%02X %02X %02X\n",
94                                skb->data[3], skb->data[4],
95                                skb->data[5], skb->data[6]);
96                         break;
97                         
98                 default:
99                         printk(KERN_WARNING "x25: received unknown %02X "
100                                "with LCI 000\n", frametype);
101                         break;
102         }
103
104         if (nb->state == X25_LINK_STATE_3)
105                 while ((skbn = skb_dequeue(&nb->queue)) != NULL)
106                         x25_send_frame(skbn, nb);
107 }
108
109 /*
110  *      This routine is called when a Restart Request is needed
111  */
112 static void x25_transmit_restart_request(struct x25_neigh *nb)
113 {
114         unsigned char *dptr;
115         int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN + 2;
116         struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
117
118         if (!skb)
119                 return;
120
121         skb_reserve(skb, X25_MAX_L2_LEN);
122
123         dptr = skb_put(skb, X25_STD_MIN_LEN + 2);
124
125         *dptr++ = nb->extended ? X25_GFI_EXTSEQ : X25_GFI_STDSEQ;
126         *dptr++ = 0x00;
127         *dptr++ = X25_RESTART_REQUEST;
128         *dptr++ = 0x00;
129         *dptr++ = 0;
130
131         skb->sk = NULL;
132
133         x25_send_frame(skb, nb);
134 }
135
136 /*
137  * This routine is called when a Restart Confirmation is needed
138  */
139 static void x25_transmit_restart_confirmation(struct x25_neigh *nb)
140 {
141         unsigned char *dptr;
142         int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN;
143         struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
144
145         if (!skb)
146                 return;
147
148         skb_reserve(skb, X25_MAX_L2_LEN);
149
150         dptr = skb_put(skb, X25_STD_MIN_LEN);
151
152         *dptr++ = nb->extended ? X25_GFI_EXTSEQ : X25_GFI_STDSEQ;
153         *dptr++ = 0x00;
154         *dptr++ = X25_RESTART_CONFIRMATION;
155
156         skb->sk = NULL;
157
158         x25_send_frame(skb, nb);
159 }
160
161 /*
162  *      This routine is called when a Clear Request is needed outside of the context
163  *      of a connected socket.
164  */
165 void x25_transmit_clear_request(struct x25_neigh *nb, unsigned int lci,
166                                 unsigned char cause)
167 {
168         unsigned char *dptr;
169         int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN + 2;
170         struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
171
172         if (!skb)
173                 return;
174
175         skb_reserve(skb, X25_MAX_L2_LEN);
176
177         dptr = skb_put(skb, X25_STD_MIN_LEN + 2);
178
179         *dptr++ = ((lci >> 8) & 0x0F) | (nb->extended ?
180                                          X25_GFI_EXTSEQ :
181                                          X25_GFI_STDSEQ);
182         *dptr++ = (lci >> 0) & 0xFF;
183         *dptr++ = X25_CLEAR_REQUEST;
184         *dptr++ = cause;
185         *dptr++ = 0x00;
186
187         skb->sk = NULL;
188
189         x25_send_frame(skb, nb);
190 }
191
192 void x25_transmit_link(struct sk_buff *skb, struct x25_neigh *nb)
193 {
194         switch (nb->state) {
195                 case X25_LINK_STATE_0:
196                         skb_queue_tail(&nb->queue, skb);
197                         nb->state = X25_LINK_STATE_1;
198                         x25_establish_link(nb);
199                         break;
200                 case X25_LINK_STATE_1:
201                 case X25_LINK_STATE_2:
202                         skb_queue_tail(&nb->queue, skb);
203                         break;
204                 case X25_LINK_STATE_3:
205                         x25_send_frame(skb, nb);
206                         break;
207         }
208 }
209
210 /*
211  *      Called when the link layer has become established.
212  */
213 void x25_link_established(struct x25_neigh *nb)
214 {
215         switch (nb->state) {
216                 case X25_LINK_STATE_0:
217                         nb->state = X25_LINK_STATE_2;
218                         break;
219                 case X25_LINK_STATE_1:
220                         x25_transmit_restart_request(nb);
221                         nb->state = X25_LINK_STATE_2;
222                         x25_start_t20timer(nb);
223                         break;
224         }
225 }
226
227 /*
228  *      Called when the link layer has terminated, or an establishment
229  *      request has failed.
230  */
231
232 void x25_link_terminated(struct x25_neigh *nb)
233 {
234         nb->state = X25_LINK_STATE_0;
235         /* Out of order: clear existing virtual calls (X.25 03/93 4.6.3) */
236         x25_kill_by_neigh(nb);
237 }
238
239 /*
240  *      Add a new device.
241  */
242 void x25_link_device_up(struct net_device *dev)
243 {
244         struct x25_neigh *nb = kmalloc(sizeof(*nb), GFP_ATOMIC);
245
246         if (!nb)
247                 return;
248
249         skb_queue_head_init(&nb->queue);
250
251         init_timer(&nb->t20timer);
252         nb->t20timer.data     = (unsigned long)nb;
253         nb->t20timer.function = &x25_t20timer_expiry;
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  */
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  */
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  */
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  */
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                 x25_subscr.extended          = nb->extended;
366                 x25_subscr.global_facil_mask = nb->global_facil_mask;
367                 rc = copy_to_user(arg, &x25_subscr,
368                                   sizeof(x25_subscr)) ? -EFAULT : 0;
369         } else {
370                 rc = -EINVAL;
371                 if (!(x25_subscr.extended && x25_subscr.extended != 1)) {
372                         rc = 0;
373                         nb->extended         = x25_subscr.extended;
374                         nb->global_facil_mask = x25_subscr.global_facil_mask;
375                 }
376         }
377         x25_neigh_put(nb);
378 out:
379         return rc;
380 out_dev_put:
381         dev_put(dev);
382         goto out;
383 }
384
385
386 /*
387  *      Release all memory associated with X.25 neighbour structures.
388  */
389 void __exit x25_link_free(void)
390 {
391         struct x25_neigh *nb;
392         struct list_head *entry, *tmp;
393
394         write_lock_bh(&x25_neigh_list_lock);
395
396         list_for_each_safe(entry, tmp, &x25_neigh_list) {
397                 nb = list_entry(entry, struct x25_neigh, node);
398                 __x25_remove_neigh(nb);
399         }
400         write_unlock_bh(&x25_neigh_list_lock);
401 }