1 // SPDX-License-Identifier: GPL-2.0-or-later 1
2 /*
3 * X.25 Packet Layer release 002
4 *
5 * This is ALPHA test software. This code
6 * randomly fail to work with new release
7 * screw up. It might even work.
8 *
9 * This code REQUIRES 2.1.15 or higher
10 *
11 * History
12 * X.25 001 Jonathan Naylor Star
13 * X.25 002 Jonathan Naylor Cent
14 * New
15 * 2000-03-20 Daniela Squassoni Disa
16 * nego
17 * 2000-11-10 Henner Eisen Chec
18 * i-fr
19 */
20
21 #define pr_fmt(fmt) "X25: " fmt
22
23 #include <linux/slab.h>
24 #include <linux/errno.h>
25 #include <linux/kernel.h>
26 #include <linux/string.h>
27 #include <linux/skbuff.h>
28 #include <net/sock.h>
29 #include <net/tcp_states.h>
30 #include <net/x25.h>
31
32 static int x25_queue_rx_frame(struct sock *sk,
33 {
34 struct sk_buff *skbo, *skbn = skb;
35 struct x25_sock *x25 = x25_sk(sk);
36
37 if (more) {
38 x25->fraglen += skb->len;
39 skb_queue_tail(&x25->fragment_
40 skb_set_owner_r(skb, sk);
41 return 0;
42 }
43
44 if (x25->fraglen > 0) { /* End of frag
45 int len = x25->fraglen + skb->
46
47 if ((skbn = alloc_skb(len, GFP
48 kfree_skb(skb);
49 return 1;
50 }
51
52 skb_queue_tail(&x25->fragment_
53
54 skb_reset_transport_header(skb
55
56 skbo = skb_dequeue(&x25->fragm
57 skb_copy_from_linear_data(skbo
58 skbo
59 kfree_skb(skbo);
60
61 while ((skbo =
62 skb_dequeue(&x25->frag
63 skb_pull(skbo, (x25->n
64 X25_EX
65 skb_copy_from_linear_d
66
67
68 kfree_skb(skbo);
69 }
70
71 x25->fraglen = 0;
72 }
73
74 skb_set_owner_r(skbn, sk);
75 skb_queue_tail(&sk->sk_receive_queue,
76 if (!sock_flag(sk, SOCK_DEAD))
77 sk->sk_data_ready(sk);
78
79 return 0;
80 }
81
82 /*
83 * State machine for state 1, Awaiting Call Ac
84 * The handling of the timer(s) is in file x25
85 * Handling of state 0 and connection release
86 */
87 static int x25_state1_machine(struct sock *sk,
88 {
89 struct x25_address source_addr, dest_a
90 int len;
91 struct x25_sock *x25 = x25_sk(sk);
92
93 switch (frametype) {
94 case X25_CALL_ACCEPTED: {
95
96 x25_stop_timer(sk);
97 x25->condition = 0x00;
98 x25->vs = 0;
99 x25->va = 0;
100 x25->vr = 0;
101 x25->vl = 0;
102 x25->state = X25_STATE_3;
103 sk->sk_state = TCP_ESTABLISH
104 /*
105 * Parse the data in the
106 */
107 if (!pskb_may_pull(skb, X25_ST
108 goto out_clear;
109 skb_pull(skb, X25_STD_MIN_LEN)
110
111 len = x25_parse_address_block(
112
113 if (len > 0)
114 skb_pull(skb, len);
115 else if (len < 0)
116 goto out_clear;
117
118 len = x25_parse_facilities(skb
119 &x2
120 &x2
121 if (len > 0)
122 skb_pull(skb, len);
123 else if (len < 0)
124 goto out_clear;
125 /*
126 * Copy any Call User Dat
127 */
128 if (skb->len > 0) {
129 if (skb->len > X25_MAX
130 goto out_clear
131
132 skb_copy_bits(skb, 0,
133 skb->len);
134 x25->calluserdata.cudl
135 }
136 if (!sock_flag(sk, SOCK_DEAD))
137 sk->sk_state_change(sk
138 break;
139 }
140 case X25_CALL_REQUEST:
141 /* call collision */
142 x25->causediag.cause = 0x
143 x25->causediag.diagnostic = 0x
144
145 x25_write_internal(sk, X25_CLE
146 x25_disconnect(sk, EISCONN, 0x
147 break;
148
149 case X25_CLEAR_REQUEST:
150 if (!pskb_may_pull(skb, X25_ST
151 goto out_clear;
152
153 x25_write_internal(sk, X25_CLE
154 x25_disconnect(sk, ECONNREFUSE
155 break;
156
157 default:
158 break;
159 }
160
161 return 0;
162
163 out_clear:
164 x25_write_internal(sk, X25_CLEAR_REQUE
165 x25->state = X25_STATE_2;
166 x25_start_t23timer(sk);
167 return 0;
168 }
169
170 /*
171 * State machine for state 2, Awaiting Clear C
172 * The handling of the timer(s) is in file x25
173 * Handling of state 0 and connection release
174 */
175 static int x25_state2_machine(struct sock *sk,
176 {
177 switch (frametype) {
178
179 case X25_CLEAR_REQUEST:
180 if (!pskb_may_pull(skb
181 goto out_clear
182
183 x25_write_internal(sk,
184 x25_disconnect(sk, 0,
185 break;
186
187 case X25_CLEAR_CONFIRMATION:
188 x25_disconnect(sk, 0,
189 break;
190
191 default:
192 break;
193 }
194
195 return 0;
196
197 out_clear:
198 x25_write_internal(sk, X25_CLEAR_REQUE
199 x25_start_t23timer(sk);
200 return 0;
201 }
202
203 /*
204 * State machine for state 3, Connected State.
205 * The handling of the timer(s) is in file x25
206 * Handling of state 0 and connection release
207 */
208 static int x25_state3_machine(struct sock *sk,
209 {
210 int queued = 0;
211 int modulus;
212 struct x25_sock *x25 = x25_sk(sk);
213
214 modulus = (x25->neighbour->extended) ?
215
216 switch (frametype) {
217
218 case X25_RESET_REQUEST:
219 x25_write_internal(sk,
220 x25_stop_timer(sk);
221 x25->condition = 0x00;
222 x25->vs = 0;
223 x25->vr = 0;
224 x25->va = 0;
225 x25->vl = 0;
226 x25_requeue_frames(sk)
227 break;
228
229 case X25_CLEAR_REQUEST:
230 if (!pskb_may_pull(skb
231 goto out_clear
232
233 x25_write_internal(sk,
234 x25_disconnect(sk, 0,
235 break;
236
237 case X25_RR:
238 case X25_RNR:
239 if (!x25_validate_nr(s
240 x25_clear_queu
241 x25_write_inte
242 x25_start_t22t
243 x25->condition
244 x25->vs
245 x25->vr
246 x25->va
247 x25->vl
248 x25->state
249 } else {
250 x25_frames_ack
251 if (frametype
252 x25->c
253 } else {
254 x25->c
255 }
256 }
257 break;
258
259 case X25_DATA: /* XXX */
260 x25->condition &= ~X25
261 if ((ns != x25->vr) ||
262 x25_clear_queu
263 x25_write_inte
264 x25_start_t22t
265 x25->condition
266 x25->vs
267 x25->vr
268 x25->va
269 x25->vl
270 x25->state
271 break;
272 }
273 x25_frames_acked(sk, n
274 if (ns == x25->vr) {
275 if (x25_queue_
276 x25->v
277 queued
278 } else {
279 /* Sho
280 x25_cl
281 x25_wr
282 x25_st
283 x25->c
284 x25->v
285 x25->v
286 x25->v
287 x25->v
288 x25->s
289 break;
290 }
291 if (atomic_rea
292 (sk->sk_rc
293 x25->c
294 }
295 /*
296 * If the window
297 * start the hold
298 */
299 if (((x25->vl + x25->f
300 x25->condition
301 x25_stop_timer
302 x25_enquiry_re
303 } else {
304 x25->condition
305 x25_start_t2ti
306 }
307 break;
308
309 case X25_INTERRUPT_CONFIRMATIO
310 clear_bit(X25_INTERRUP
311 break;
312
313 case X25_INTERRUPT:
314 if (sock_flag(sk, SOCK
315 queued = !sock
316 else {
317 skb_set_owner_
318 skb_queue_tail
319 queued = 1;
320 }
321 sk_send_sigurg(sk);
322 x25_write_internal(sk,
323 break;
324
325 default:
326 pr_warn("unknown %02X
327 break;
328 }
329
330 return queued;
331
332 out_clear:
333 x25_write_internal(sk, X25_CLEAR_REQUE
334 x25->state = X25_STATE_2;
335 x25_start_t23timer(sk);
336 return 0;
337 }
338
339 /*
340 * State machine for state 4, Awaiting Reset C
341 * The handling of the timer(s) is in file x25
342 * Handling of state 0 and connection release
343 */
344 static int x25_state4_machine(struct sock *sk,
345 {
346 struct x25_sock *x25 = x25_sk(sk);
347
348 switch (frametype) {
349
350 case X25_RESET_REQUEST:
351 x25_write_internal(sk,
352 fallthrough;
353 case X25_RESET_CONFIRMATION: {
354 x25_stop_timer(sk);
355 x25->condition = 0x00;
356 x25->va = 0;
357 x25->vr = 0;
358 x25->vs = 0;
359 x25->vl = 0;
360 x25->state = X25_S
361 x25_requeue_frames(sk)
362 break;
363 }
364 case X25_CLEAR_REQUEST:
365 if (!pskb_may_pull(skb
366 goto out_clear
367
368 x25_write_internal(sk,
369 x25_disconnect(sk, 0,
370 break;
371
372 default:
373 break;
374 }
375
376 return 0;
377
378 out_clear:
379 x25_write_internal(sk, X25_CLEAR_REQUE
380 x25->state = X25_STATE_2;
381 x25_start_t23timer(sk);
382 return 0;
383 }
384
385 /*
386 * State machine for state 5, Call Accepted /
387 * The handling of the timer(s) is in file x25
388 * Handling of state 0 and connection release
389 */
390 static int x25_state5_machine(struct sock *sk,
391 {
392 struct x25_sock *x25 = x25_sk(sk);
393
394 switch (frametype) {
395 case X25_CLEAR_REQUEST:
396 if (!pskb_may_pull(skb
397 x25_write_inte
398 x25->state = X
399 x25_start_t23t
400 return 0;
401 }
402
403 x25_write_internal(sk,
404 x25_disconnect(sk, 0,
405 break;
406
407 default:
408 break;
409 }
410
411 return 0;
412 }
413
414 /* Higher level upcall for a LAPB frame */
415 int x25_process_rx_frame(struct sock *sk, stru
416 {
417 struct x25_sock *x25 = x25_sk(sk);
418 int queued = 0, frametype, ns, nr, q,
419
420 if (x25->state == X25_STATE_0)
421 return 0;
422
423 frametype = x25_decode(sk, skb, &ns, &
424
425 switch (x25->state) {
426 case X25_STATE_1:
427 queued = x25_state1_machine(sk
428 break;
429 case X25_STATE_2:
430 queued = x25_state2_machine(sk
431 break;
432 case X25_STATE_3:
433 queued = x25_state3_machine(sk
434 break;
435 case X25_STATE_4:
436 queued = x25_state4_machine(sk
437 break;
438 case X25_STATE_5:
439 queued = x25_state5_machine(sk
440 break;
441 }
442
443 x25_kick(sk);
444
445 return queued;
446 }
447
448 int x25_backlog_rcv(struct sock *sk, struct sk
449 {
450 int queued = x25_process_rx_frame(sk,
451
452 if (!queued)
453 kfree_skb(skb);
454
455 return 0;
456 }
457
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