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Merge tag 'sound-5.1-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai...
[thirdparty/kernel/stable.git] / net / x25 / x25_in.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 Centralised disconnection code.
19 * New timer architecture.
20 * 2000-03-20 Daniela Squassoni Disabling/enabling of facilities
21 * negotiation.
22 * 2000-11-10 Henner Eisen Check and reset for out-of-sequence
23 * i-frames.
24 */
25
26 #define pr_fmt(fmt) "X25: " fmt
27
28 #include <linux/slab.h>
29 #include <linux/errno.h>
30 #include <linux/kernel.h>
31 #include <linux/string.h>
32 #include <linux/skbuff.h>
33 #include <net/sock.h>
34 #include <net/tcp_states.h>
35 #include <net/x25.h>
36
37 static int x25_queue_rx_frame(struct sock *sk, struct sk_buff *skb, int more)
38 {
39 struct sk_buff *skbo, *skbn = skb;
40 struct x25_sock *x25 = x25_sk(sk);
41
42 if (more) {
43 x25->fraglen += skb->len;
44 skb_queue_tail(&x25->fragment_queue, skb);
45 skb_set_owner_r(skb, sk);
46 return 0;
47 }
48
49 if (!more && x25->fraglen > 0) { /* End of fragment */
50 int len = x25->fraglen + skb->len;
51
52 if ((skbn = alloc_skb(len, GFP_ATOMIC)) == NULL){
53 kfree_skb(skb);
54 return 1;
55 }
56
57 skb_queue_tail(&x25->fragment_queue, skb);
58
59 skb_reset_transport_header(skbn);
60
61 skbo = skb_dequeue(&x25->fragment_queue);
62 skb_copy_from_linear_data(skbo, skb_put(skbn, skbo->len),
63 skbo->len);
64 kfree_skb(skbo);
65
66 while ((skbo =
67 skb_dequeue(&x25->fragment_queue)) != NULL) {
68 skb_pull(skbo, (x25->neighbour->extended) ?
69 X25_EXT_MIN_LEN : X25_STD_MIN_LEN);
70 skb_copy_from_linear_data(skbo,
71 skb_put(skbn, skbo->len),
72 skbo->len);
73 kfree_skb(skbo);
74 }
75
76 x25->fraglen = 0;
77 }
78
79 skb_set_owner_r(skbn, sk);
80 skb_queue_tail(&sk->sk_receive_queue, skbn);
81 if (!sock_flag(sk, SOCK_DEAD))
82 sk->sk_data_ready(sk);
83
84 return 0;
85 }
86
87 /*
88 * State machine for state 1, Awaiting Call Accepted State.
89 * The handling of the timer(s) is in file x25_timer.c.
90 * Handling of state 0 and connection release is in af_x25.c.
91 */
92 static int x25_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype)
93 {
94 struct x25_address source_addr, dest_addr;
95 int len;
96 struct x25_sock *x25 = x25_sk(sk);
97
98 switch (frametype) {
99 case X25_CALL_ACCEPTED: {
100
101 x25_stop_timer(sk);
102 x25->condition = 0x00;
103 x25->vs = 0;
104 x25->va = 0;
105 x25->vr = 0;
106 x25->vl = 0;
107 x25->state = X25_STATE_3;
108 sk->sk_state = TCP_ESTABLISHED;
109 /*
110 * Parse the data in the frame.
111 */
112 if (!pskb_may_pull(skb, X25_STD_MIN_LEN))
113 goto out_clear;
114 skb_pull(skb, X25_STD_MIN_LEN);
115
116 len = x25_parse_address_block(skb, &source_addr,
117 &dest_addr);
118 if (len > 0)
119 skb_pull(skb, len);
120 else if (len < 0)
121 goto out_clear;
122
123 len = x25_parse_facilities(skb, &x25->facilities,
124 &x25->dte_facilities,
125 &x25->vc_facil_mask);
126 if (len > 0)
127 skb_pull(skb, len);
128 else if (len < 0)
129 goto out_clear;
130 /*
131 * Copy any Call User Data.
132 */
133 if (skb->len > 0) {
134 if (skb->len > X25_MAX_CUD_LEN)
135 goto out_clear;
136
137 skb_copy_bits(skb, 0, x25->calluserdata.cuddata,
138 skb->len);
139 x25->calluserdata.cudlength = skb->len;
140 }
141 if (!sock_flag(sk, SOCK_DEAD))
142 sk->sk_state_change(sk);
143 break;
144 }
145 case X25_CALL_REQUEST:
146 /* call collision */
147 x25->causediag.cause = 0x01;
148 x25->causediag.diagnostic = 0x48;
149
150 x25_write_internal(sk, X25_CLEAR_REQUEST);
151 x25_disconnect(sk, EISCONN, 0x01, 0x48);
152 break;
153
154 case X25_CLEAR_REQUEST:
155 if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 2))
156 goto out_clear;
157
158 x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
159 x25_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]);
160 break;
161
162 default:
163 break;
164 }
165
166 return 0;
167
168 out_clear:
169 x25_write_internal(sk, X25_CLEAR_REQUEST);
170 x25->state = X25_STATE_2;
171 x25_start_t23timer(sk);
172 return 0;
173 }
174
175 /*
176 * State machine for state 2, Awaiting Clear Confirmation State.
177 * The handling of the timer(s) is in file x25_timer.c
178 * Handling of state 0 and connection release is in af_x25.c.
179 */
180 static int x25_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype)
181 {
182 switch (frametype) {
183
184 case X25_CLEAR_REQUEST:
185 if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 2))
186 goto out_clear;
187
188 x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
189 x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
190 break;
191
192 case X25_CLEAR_CONFIRMATION:
193 x25_disconnect(sk, 0, 0, 0);
194 break;
195
196 default:
197 break;
198 }
199
200 return 0;
201
202 out_clear:
203 x25_write_internal(sk, X25_CLEAR_REQUEST);
204 x25_start_t23timer(sk);
205 return 0;
206 }
207
208 /*
209 * State machine for state 3, Connected State.
210 * The handling of the timer(s) is in file x25_timer.c
211 * Handling of state 0 and connection release is in af_x25.c.
212 */
213 static int x25_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype, int ns, int nr, int q, int d, int m)
214 {
215 int queued = 0;
216 int modulus;
217 struct x25_sock *x25 = x25_sk(sk);
218
219 modulus = (x25->neighbour->extended) ? X25_EMODULUS : X25_SMODULUS;
220
221 switch (frametype) {
222
223 case X25_RESET_REQUEST:
224 x25_write_internal(sk, X25_RESET_CONFIRMATION);
225 x25_stop_timer(sk);
226 x25->condition = 0x00;
227 x25->vs = 0;
228 x25->vr = 0;
229 x25->va = 0;
230 x25->vl = 0;
231 x25_requeue_frames(sk);
232 break;
233
234 case X25_CLEAR_REQUEST:
235 if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 2))
236 goto out_clear;
237
238 x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
239 x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
240 break;
241
242 case X25_RR:
243 case X25_RNR:
244 if (!x25_validate_nr(sk, nr)) {
245 x25_clear_queues(sk);
246 x25_write_internal(sk, X25_RESET_REQUEST);
247 x25_start_t22timer(sk);
248 x25->condition = 0x00;
249 x25->vs = 0;
250 x25->vr = 0;
251 x25->va = 0;
252 x25->vl = 0;
253 x25->state = X25_STATE_4;
254 } else {
255 x25_frames_acked(sk, nr);
256 if (frametype == X25_RNR) {
257 x25->condition |= X25_COND_PEER_RX_BUSY;
258 } else {
259 x25->condition &= ~X25_COND_PEER_RX_BUSY;
260 }
261 }
262 break;
263
264 case X25_DATA: /* XXX */
265 x25->condition &= ~X25_COND_PEER_RX_BUSY;
266 if ((ns != x25->vr) || !x25_validate_nr(sk, nr)) {
267 x25_clear_queues(sk);
268 x25_write_internal(sk, X25_RESET_REQUEST);
269 x25_start_t22timer(sk);
270 x25->condition = 0x00;
271 x25->vs = 0;
272 x25->vr = 0;
273 x25->va = 0;
274 x25->vl = 0;
275 x25->state = X25_STATE_4;
276 break;
277 }
278 x25_frames_acked(sk, nr);
279 if (ns == x25->vr) {
280 if (x25_queue_rx_frame(sk, skb, m) == 0) {
281 x25->vr = (x25->vr + 1) % modulus;
282 queued = 1;
283 } else {
284 /* Should never happen */
285 x25_clear_queues(sk);
286 x25_write_internal(sk, X25_RESET_REQUEST);
287 x25_start_t22timer(sk);
288 x25->condition = 0x00;
289 x25->vs = 0;
290 x25->vr = 0;
291 x25->va = 0;
292 x25->vl = 0;
293 x25->state = X25_STATE_4;
294 break;
295 }
296 if (atomic_read(&sk->sk_rmem_alloc) >
297 (sk->sk_rcvbuf >> 1))
298 x25->condition |= X25_COND_OWN_RX_BUSY;
299 }
300 /*
301 * If the window is full Ack it immediately, else
302 * start the holdback timer.
303 */
304 if (((x25->vl + x25->facilities.winsize_in) % modulus) == x25->vr) {
305 x25->condition &= ~X25_COND_ACK_PENDING;
306 x25_stop_timer(sk);
307 x25_enquiry_response(sk);
308 } else {
309 x25->condition |= X25_COND_ACK_PENDING;
310 x25_start_t2timer(sk);
311 }
312 break;
313
314 case X25_INTERRUPT_CONFIRMATION:
315 clear_bit(X25_INTERRUPT_FLAG, &x25->flags);
316 break;
317
318 case X25_INTERRUPT:
319 if (sock_flag(sk, SOCK_URGINLINE))
320 queued = !sock_queue_rcv_skb(sk, skb);
321 else {
322 skb_set_owner_r(skb, sk);
323 skb_queue_tail(&x25->interrupt_in_queue, skb);
324 queued = 1;
325 }
326 sk_send_sigurg(sk);
327 x25_write_internal(sk, X25_INTERRUPT_CONFIRMATION);
328 break;
329
330 default:
331 pr_warn("unknown %02X in state 3\n", frametype);
332 break;
333 }
334
335 return queued;
336
337 out_clear:
338 x25_write_internal(sk, X25_CLEAR_REQUEST);
339 x25->state = X25_STATE_2;
340 x25_start_t23timer(sk);
341 return 0;
342 }
343
344 /*
345 * State machine for state 4, Awaiting Reset Confirmation State.
346 * The handling of the timer(s) is in file x25_timer.c
347 * Handling of state 0 and connection release is in af_x25.c.
348 */
349 static int x25_state4_machine(struct sock *sk, struct sk_buff *skb, int frametype)
350 {
351 struct x25_sock *x25 = x25_sk(sk);
352
353 switch (frametype) {
354
355 case X25_RESET_REQUEST:
356 x25_write_internal(sk, X25_RESET_CONFIRMATION);
357 /* fall through */
358 case X25_RESET_CONFIRMATION: {
359 x25_stop_timer(sk);
360 x25->condition = 0x00;
361 x25->va = 0;
362 x25->vr = 0;
363 x25->vs = 0;
364 x25->vl = 0;
365 x25->state = X25_STATE_3;
366 x25_requeue_frames(sk);
367 break;
368 }
369 case X25_CLEAR_REQUEST:
370 if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 2))
371 goto out_clear;
372
373 x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
374 x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
375 break;
376
377 default:
378 break;
379 }
380
381 return 0;
382
383 out_clear:
384 x25_write_internal(sk, X25_CLEAR_REQUEST);
385 x25->state = X25_STATE_2;
386 x25_start_t23timer(sk);
387 return 0;
388 }
389
390 /* Higher level upcall for a LAPB frame */
391 int x25_process_rx_frame(struct sock *sk, struct sk_buff *skb)
392 {
393 struct x25_sock *x25 = x25_sk(sk);
394 int queued = 0, frametype, ns, nr, q, d, m;
395
396 if (x25->state == X25_STATE_0)
397 return 0;
398
399 frametype = x25_decode(sk, skb, &ns, &nr, &q, &d, &m);
400
401 switch (x25->state) {
402 case X25_STATE_1:
403 queued = x25_state1_machine(sk, skb, frametype);
404 break;
405 case X25_STATE_2:
406 queued = x25_state2_machine(sk, skb, frametype);
407 break;
408 case X25_STATE_3:
409 queued = x25_state3_machine(sk, skb, frametype, ns, nr, q, d, m);
410 break;
411 case X25_STATE_4:
412 queued = x25_state4_machine(sk, skb, frametype);
413 break;
414 }
415
416 x25_kick(sk);
417
418 return queued;
419 }
420
421 int x25_backlog_rcv(struct sock *sk, struct sk_buff *skb)
422 {
423 int queued = x25_process_rx_frame(sk, skb);
424
425 if (!queued)
426 kfree_skb(skb);
427
428 return 0;
429 }
Mirror https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git