1 /*
2 * X.25 Packet Layer release 002
3 *
4 * This is ALPHA test software. This code may break your machine, randomly fail to work with new
5 * releases, misbehave and/or generally screw up. It might even work.
6 *
7 * This code REQUIRES 2.1.15 or higher
8 *
9 * This module:
10 * This module is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
14 *
15 * History
16 * X.25 001 Jonathan Naylor Started coding.
17 * X.25 002 Jonathan Naylor Centralised disconnection processing.
18 * mar/20/00 Daniela Squassoni Disabling/enabling of facilities
19 * negotiation.
20 */
21
22 #include <linux/config.h>
23 #if defined(CONFIG_X25) || defined(CONFIG_X25_MODULE)
24 #include <linux/errno.h>
25 #include <linux/types.h>
26 #include <linux/socket.h>
27 #include <linux/in.h>
28 #include <linux/kernel.h>
29 #include <linux/sched.h>
30 #include <linux/timer.h>
31 #include <linux/string.h>
32 #include <linux/sockios.h>
33 #include <linux/net.h>
34 #include <linux/inet.h>
35 #include <linux/netdevice.h>
36 #include <linux/skbuff.h>
37 #include <net/sock.h>
38 #include <asm/segment.h>
39 #include <asm/system.h>
40 #include <linux/fcntl.h>
41 #include <linux/mm.h>
42 #include <linux/interrupt.h>
43 #include <net/x25.h>
44
45 /*
46 * This routine purges all of the queues of frames.
47 */
48 void x25_clear_queues(struct sock *sk)
49 {
50 struct sk_buff *skb;
51
52 while ((skb = skb_dequeue(&sk->write_queue)) != NULL)
53 kfree_skb(skb);
54
55 while ((skb = skb_dequeue(&sk->protinfo.x25->ack_queue)) != NULL)
56 kfree_skb(skb);
57
58 while ((skb = skb_dequeue(&sk->protinfo.x25->interrupt_in_queue)) != NULL)
59 kfree_skb(skb);
60
61 while ((skb = skb_dequeue(&sk->protinfo.x25->interrupt_out_queue)) != NULL)
62 kfree_skb(skb);
63
64 while ((skb = skb_dequeue(&sk->protinfo.x25->fragment_queue)) != NULL)
65 kfree_skb(skb);
66 }
67
68
69 /*
70 * This routine purges the input queue of those frames that have been
71 * acknowledged. This replaces the boxes labelled "V(a) <- N(r)" on the
72 * SDL diagram.
73 */
74 void x25_frames_acked(struct sock *sk, unsigned short nr)
75 {
76 struct sk_buff *skb;
77 int modulus;
78
79 modulus = (sk->protinfo.x25->neighbour->extended) ? X25_EMODULUS : X25_SMODULUS;
80
81 /*
82 * Remove all the ack-ed frames from the ack queue.
83 */
84 if (sk->protinfo.x25->va != nr) {
85 while (skb_peek(&sk->protinfo.x25->ack_queue) != NULL && sk->protinfo.x25->va != nr) {
86 skb = skb_dequeue(&sk->protinfo.x25->ack_queue);
87 kfree_skb(skb);
88 sk->protinfo.x25->va = (sk->protinfo.x25->va + 1) % modulus;
89 }
90 }
91 }
92
93 void x25_requeue_frames(struct sock *sk)
94 {
95 struct sk_buff *skb, *skb_prev = NULL;
96
97 /*
98 * Requeue all the un-ack-ed frames on the output queue to be picked
99 * up by x25_kick. This arrangement handles the possibility of an empty
100 * output queue.
101 */
102 while ((skb = skb_dequeue(&sk->protinfo.x25->ack_queue)) != NULL) {
103 if (skb_prev == NULL)
104 skb_queue_head(&sk->write_queue, skb);
105 else
106 skb_append(skb_prev, skb);
107 skb_prev = skb;
108 }
109 }
110
111 /*
112 * Validate that the value of nr is between va and vs. Return true or
113 * false for testing.
114 */
115 int x25_validate_nr(struct sock *sk, unsigned short nr)
116 {
117 unsigned short vc = sk->protinfo.x25->va;
118 int modulus;
119
120 modulus = (sk->protinfo.x25->neighbour->extended) ? X25_EMODULUS : X25_SMODULUS;
121
122 while (vc != sk->protinfo.x25->vs) {
123 if (nr == vc) return 1;
124 vc = (vc + 1) % modulus;
125 }
126
127 if (nr == sk->protinfo.x25->vs) return 1;
128
129 return 0;
130 }
131
132 /*
133 * This routine is called when the packet layer internally generates a
134 * control frame.
135 */
136 void x25_write_internal(struct sock *sk, int frametype)
137 {
138 struct sk_buff *skb;
139 unsigned char *dptr;
140 unsigned char facilities[X25_MAX_FAC_LEN];
141 unsigned char addresses[1 + X25_ADDR_LEN];
142 unsigned char lci1, lci2;
143 int len;
144
145 /*
146 * Default safe frame size.
147 */
148 len = X25_MAX_L2_LEN + X25_EXT_MIN_LEN;
149
150 /*
151 * Adjust frame size.
152 */
153 switch (frametype) {
154 case X25_CALL_REQUEST:
155 len += 1 + X25_ADDR_LEN + X25_MAX_FAC_LEN + X25_MAX_CUD_LEN;
156 break;
157 case X25_CALL_ACCEPTED:
158 len += 1 + X25_MAX_FAC_LEN + X25_MAX_CUD_LEN;
159 break;
160 case X25_CLEAR_REQUEST:
161 case X25_RESET_REQUEST:
162 len += 2;
163 break;
164 case X25_RR:
165 case X25_RNR:
166 case X25_REJ:
167 case X25_CLEAR_CONFIRMATION:
168 case X25_INTERRUPT_CONFIRMATION:
169 case X25_RESET_CONFIRMATION:
170 break;
171 default:
172 printk(KERN_ERR "X.25: invalid frame type %02X\n", frametype);
173 return;
174 }
175
176 if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
177 return;
178
179 /*
180 * Space for Ethernet and 802.2 LLC headers.
181 */
182 skb_reserve(skb, X25_MAX_L2_LEN);
183
184 /*
185 * Make space for the GFI and LCI, and fill them in.
186 */
187 dptr = skb_put(skb, 2);
188
189 lci1 = (sk->protinfo.x25->lci >> 8) & 0x0F;
190 lci2 = (sk->protinfo.x25->lci >> 0) & 0xFF;
191
192 if (sk->protinfo.x25->neighbour->extended) {
193 *dptr++ = lci1 | X25_GFI_EXTSEQ;
194 *dptr++ = lci2;
195 } else {
196 *dptr++ = lci1 | X25_GFI_STDSEQ;
197 *dptr++ = lci2;
198 }
199
200 /*
201 * Now fill in the frame type specific information.
202 */
203 switch (frametype) {
204
205 case X25_CALL_REQUEST:
206 dptr = skb_put(skb, 1);
207 *dptr++ = X25_CALL_REQUEST;
208 len = x25_addr_aton(addresses, &sk->protinfo.x25->dest_addr, &sk->protinfo.x25->source_addr);
209 dptr = skb_put(skb, len);
210 memcpy(dptr, addresses, len);
211 len = x25_create_facilities(facilities, &sk->protinfo.x25->facilities, sk->protinfo.x25->neighbour->global_facil_mask);
212 dptr = skb_put(skb, len);
213 memcpy(dptr, facilities, len);
214 dptr = skb_put(skb, sk->protinfo.x25->calluserdata.cudlength);
215 memcpy(dptr, sk->protinfo.x25->calluserdata.cuddata, sk->protinfo.x25->calluserdata.cudlength);
216 sk->protinfo.x25->calluserdata.cudlength = 0;
217 break;
218
219 case X25_CALL_ACCEPTED:
220 dptr = skb_put(skb, 2);
221 *dptr++ = X25_CALL_ACCEPTED;
222 *dptr++ = 0x00; /* Address lengths */
223 len = x25_create_facilities(facilities, &sk->protinfo.x25->facilities, sk->protinfo.x25->vc_facil_mask);
224 dptr = skb_put(skb, len);
225 memcpy(dptr, facilities, len);
226 dptr = skb_put(skb, sk->protinfo.x25->calluserdata.cudlength);
227 memcpy(dptr, sk->protinfo.x25->calluserdata.cuddata, sk->protinfo.x25->calluserdata.cudlength);
228 sk->protinfo.x25->calluserdata.cudlength = 0;
229 break;
230
231 case X25_CLEAR_REQUEST:
232 case X25_RESET_REQUEST:
233 dptr = skb_put(skb, 3);
234 *dptr++ = frametype;
235 *dptr++ = 0x00; /* XXX */
236 *dptr++ = 0x00; /* XXX */
237 break;
238
239 case X25_RR:
240 case X25_RNR:
241 case X25_REJ:
242 if (sk->protinfo.x25->neighbour->extended) {
243 dptr = skb_put(skb, 2);
244 *dptr++ = frametype;
245 *dptr++ = (sk->protinfo.x25->vr << 1) & 0xFE;
246 } else {
247 dptr = skb_put(skb, 1);
248 *dptr = frametype;
249 *dptr++ |= (sk->protinfo.x25->vr << 5) & 0xE0;
250 }
251 break;
252
253 case X25_CLEAR_CONFIRMATION:
254 case X25_INTERRUPT_CONFIRMATION:
255 case X25_RESET_CONFIRMATION:
256 dptr = skb_put(skb, 1);
257 *dptr = frametype;
258 break;
259 }
260
261 x25_transmit_link(skb, sk->protinfo.x25->neighbour);
262 }
263
264 /*
265 * Unpick the contents of the passed X.25 Packet Layer frame.
266 */
267 int x25_decode(struct sock *sk, struct sk_buff *skb, int *ns, int *nr, int *q, int *d, int *m)
268 {
269 unsigned char *frame;
270
271 frame = skb->data;
272
273 *ns = *nr = *q = *d = *m = 0;
274
275 switch (frame[2]) {
276 case X25_CALL_REQUEST:
277 case X25_CALL_ACCEPTED:
278 case X25_CLEAR_REQUEST:
279 case X25_CLEAR_CONFIRMATION:
280 case X25_INTERRUPT:
281 case X25_INTERRUPT_CONFIRMATION:
282 case X25_RESET_REQUEST:
283 case X25_RESET_CONFIRMATION:
284 case X25_RESTART_REQUEST:
285 case X25_RESTART_CONFIRMATION:
286 case X25_REGISTRATION_REQUEST:
287 case X25_REGISTRATION_CONFIRMATION:
288 case X25_DIAGNOSTIC:
289 return frame[2];
290 }
291
292 if (sk->protinfo.x25->neighbour->extended) {
293 if (frame[2] == X25_RR ||
294 frame[2] == X25_RNR ||
295 frame[2] == X25_REJ) {
296 *nr = (frame[3] >> 1) & 0x7F;
297 return frame[2];
298 }
299 } else {
300 if ((frame[2] & 0x1F) == X25_RR ||
301 (frame[2] & 0x1F) == X25_RNR ||
302 (frame[2] & 0x1F) == X25_REJ) {
303 *nr = (frame[2] >> 5) & 0x07;
304 return frame[2] & 0x1F;
305 }
306 }
307
308 if (sk->protinfo.x25->neighbour->extended) {
309 if ((frame[2] & 0x01) == X25_DATA) {
310 *q = (frame[0] & X25_Q_BIT) == X25_Q_BIT;
311 *d = (frame[0] & X25_D_BIT) == X25_D_BIT;
312 *m = (frame[3] & X25_EXT_M_BIT) == X25_EXT_M_BIT;
313 *nr = (frame[3] >> 1) & 0x7F;
314 *ns = (frame[2] >> 1) & 0x7F;
315 return X25_DATA;
316 }
317 } else {
318 if ((frame[2] & 0x01) == X25_DATA) {
319 *q = (frame[0] & X25_Q_BIT) == X25_Q_BIT;
320 *d = (frame[0] & X25_D_BIT) == X25_D_BIT;
321 *m = (frame[2] & X25_STD_M_BIT) == X25_STD_M_BIT;
322 *nr = (frame[2] >> 5) & 0x07;
323 *ns = (frame[2] >> 1) & 0x07;
324 return X25_DATA;
325 }
326 }
327
328 printk(KERN_DEBUG "X.25: invalid PLP frame %02X %02X %02X\n", frame[0], frame[1], frame[2]);
329
330 return X25_ILLEGAL;
331 }
332
333 void x25_disconnect(struct sock *sk, int reason, unsigned char cause, unsigned char diagnostic)
334 {
335 x25_clear_queues(sk);
336 x25_stop_timer(sk);
337
338 sk->protinfo.x25->lci = 0;
339 sk->protinfo.x25->state = X25_STATE_0;
340
341 sk->protinfo.x25->causediag.cause = cause;
342 sk->protinfo.x25->causediag.diagnostic = diagnostic;
343
344 sk->state = TCP_CLOSE;
345 sk->err = reason;
346 sk->shutdown |= SEND_SHUTDOWN;
347
348 if (!sk->dead)
349 sk->state_change(sk);
350
351 sk->dead = 1;
352 }
353
354 #endif
355
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