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*/
1 /*
2 * AX.25 release 031
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 1.2.1 or higher/ NET3.029
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 * Most of this code is based on the SDL diagrams published in the 7th
16 * ARRL Computer Networking Conference papers. The diagrams have mistakes
17 * in them, but are mostly correct. Before you modify the code could you
18 * read the SDL diagrams as the code is not obvious and probably very
19 * easy to break;
20 *
21 * History
22 * AX.25 028a Jonathan(G4KLX) New state machine based on SDL diagrams.
23 * AX.25 028b Jonathan(G4KLX) Extracted AX25 control block from
24 * the sock structure.
25 * AX.25 029 Alan(GW4PTS) Switched to KA9Q constant names.
26 * Jonathan(G4KLX) Added IP mode registration.
27 * AX.25 030 Jonathan(G4KLX) Added AX.25 fragment reception.
28 * Upgraded state machine for SABME.
29 * Added arbitrary protocol id support.
30 * AX.25 031 Joerg(DL1BKE) Added DAMA support
31 * HaJo(DD8NE) Added Idle Disc Timer T5
32 * Joerg(DL1BKE) renamed it to "IDLE" with a slightly
33 * different behaviour. Fixed defrag
34 * routine (I hope)
35 */
36
37 #include <linux/config.h>
38 #ifdef CONFIG_AX25
39 #include <linux/errno.h>
40 #include <linux/types.h>
41 #include <linux/socket.h>
42 #include <linux/in.h>
43 #include <linux/kernel.h>
44 #include <linux/sched.h>
45 #include <linux/timer.h>
46 #include <linux/string.h>
47 #include <linux/sockios.h>
48 #include <linux/net.h>
49 #include <net/ax25.h>
50 #include <linux/inet.h>
51 #include <linux/netdevice.h>
52 #include <linux/skbuff.h>
53 #include <net/sock.h>
54 #include <net/ip.h> /* For ip_rcv */
55 #include <asm/segment.h>
56 #include <asm/system.h>
57 #include <linux/fcntl.h>
58 #include <linux/mm.h>
59 #include <linux/interrupt.h>
60 #ifdef CONFIG_NETROM
61 #include <net/netrom.h>
62 #endif
63
64 static int ax25_rx_iframe(ax25_cb *, struct sk_buff *);
65
66 /*
67 * Given a fragment, queue it on the fragment queue and if the fragment
68 * is complete, send it back to ax25_rx_iframe.
69 */
70 static int ax25_rx_fragment(ax25_cb *ax25, struct sk_buff *skb)
/* ![[next]](../icons/right.png)
![[first]](../icons/n_first.png)
![[top]](../icons/top.png)
*/
71 {
72 struct sk_buff *skbn, *skbo;
73 int hdrlen;
74
75 if (ax25->fragno != 0) {
76 if (!(*skb->data & SEG_FIRST)) {
77 if ((ax25->fragno - 1) == (*skb->data & SEG_REM)) {
78
79 /* enqueue fragment */
80
81 ax25->fragno = *skb->data & SEG_REM;
82 skb_pull(skb, 1); /* skip fragno */
83 ax25->fraglen += skb->len;
84 skb_queue_tail(&ax25->frag_queue, skb);
85
86 /* last fragment received? */
87
88 if (ax25->fragno == 0) {
89 if ((skbn = alloc_skb(AX25_MAX_HEADER_LEN + ax25->fraglen, GFP_ATOMIC)) == NULL)
90 return 0;
91
92 skbn->free = 1;
93 skbn->arp = 1;
94 skbn->dev = skb->dev;
95
96 if (ax25->sk != NULL) {
97 skbn->sk = ax25->sk;
98 ax25->sk->rmem_alloc += skbn->truesize;
99 }
100
101 /* get first fragment from queue */
102
103 skbo = skb_dequeue(&ax25->frag_queue);
104 hdrlen = skbo->data - skbo->h.raw - 2; /* skip PID & fragno */
105
106 skb_push(skbo, hdrlen + 2); /* start of address field */
107 skbn->data = skb_put(skbn, hdrlen); /* get space for info */
108 memcpy(skbn->data, skbo->data, hdrlen); /* copy address field */
109 skb_pull(skbo, hdrlen + 2); /* start of data */
110 skb_pull(skbn, hdrlen + 1); /* dito */
111
112 /* copy data from first fragment */
113
114 memcpy(skb_put(skbn, skbo->len), skbo->data, skbo->len);
115 kfree_skb(skbo, FREE_READ);
116
117 /* add other fragment's data */
118
119 while ((skbo = skb_dequeue(&ax25->frag_queue)) != NULL) {
120 memcpy(skb_put(skbn, skbo->len), skbo->data, skbo->len);
121 kfree_skb(skbo, FREE_READ);
122 }
123
124 ax25->fraglen = 0; /* reset counter */
125
126 /*
127 * mysteriously we need to re-adjust skb->data.
128 * Anyway, it seems to work. Do we have the address fields
129 * encoded TWICE in one sk_buff?
130 */
131
132 skb_pull(skbn, hdrlen);
133
134 if (ax25_rx_iframe(ax25, skbn) == 0)
135 kfree_skb(skbn, FREE_READ);
136 }
137
138 return 1;
139 }
140 }
141 } else {
142 /* first fragment received? */
143
144 if (*skb->data & SEG_FIRST) {
145 ax25->fragno = *skb->data & SEG_REM;
146 skb_pull(skb, 1); /* skip fragno */
147 ax25->fraglen = skb->len;
148 skb_queue_tail(&ax25->frag_queue, skb);
149 return 1;
150 }
151 }
152
153 return 0;
154 }
155
156 /*
157 * This is where all valid I frames are sent to, to be dispatched to
158 * whichever protocol requires them.
159 */
160 static int ax25_rx_iframe(ax25_cb *ax25, struct sk_buff *skb)
/* ![[previous]](../icons/left.png)
*/
161 {
162 volatile int queued = 0;
163 unsigned char pid;
164
165 if (skb == NULL) return 0;
166
167 pid = *skb->data;
168
169 switch (pid) {
170 #ifdef CONFIG_NETROM
171 case AX25_P_NETROM:
172 ax25->idletimer = ax25->idle = ax25_dev_get_value(ax25->device, AX25_VALUES_IDLE);
173 if (ax25_dev_get_value(ax25->device, AX25_VALUES_NETROM)) {
174 skb_pull(skb, 1); /* Remove PID */
175 queued = nr_route_frame(skb, ax25);
176 }
177 break;
178 #endif
179 #ifdef CONFIG_INET
180 case AX25_P_IP:
181 ax25->idletimer = ax25->idle = ax25_dev_get_value(ax25->device, AX25_VALUES_IDLE);
182 skb_pull(skb, 1); /* Remove PID */
183 skb->h.raw = skb->data;
184 ax25_ip_mode_set(&ax25->dest_addr, ax25->device, 'V');
185 ip_rcv(skb, ax25->device, NULL); /* Wrong ptype */
186 queued = 1;
187
188 break;
189 #endif
190 case AX25_P_SEGMENT:
191 ax25->idletimer = ax25->idle = ax25_dev_get_value(ax25->device, AX25_VALUES_IDLE);
192 skb_pull(skb, 1); /* Remove PID */
193 queued = ax25_rx_fragment(ax25, skb);
194 break;
195
196 default:
197 ax25->idletimer = ax25->idle = 0;
198 if (ax25->sk != NULL && ax25_dev_get_value(ax25->device, AX25_VALUES_TEXT) && ax25->sk->protocol == pid) {
199 if (sock_queue_rcv_skb(ax25->sk, skb) == 0) {
200 queued = 1;
201 } else {
202 ax25->condition |= OWN_RX_BUSY_CONDITION;
203 }
204 }
205 break;
206 }
207
208 return queued;
209 }
210
211 /*
212 * State machine for state 1, Awaiting Connection State.
213 * The handling of the timer(s) is in file ax25_timer.c.
214 * Handling of state 0 and connection release is in ax25.c.
215 */
216 static int ax25_state1_machine(ax25_cb *ax25, struct sk_buff *skb, int frametype, int pf, int type, int dama)
/* */
217 {
218 switch (frametype) {
219 case SABM:
220 ax25->modulus = MODULUS;
221 ax25->window = ax25_dev_get_value(ax25->device, AX25_VALUES_WINDOW);
222 ax25_send_control(ax25, UA, pf, C_RESPONSE);
223 break;
224
225 case SABME:
226 ax25->modulus = EMODULUS;
227 ax25->window = ax25_dev_get_value(ax25->device, AX25_VALUES_EWINDOW);
228 ax25_send_control(ax25, UA, pf, C_RESPONSE);
229 break;
230
231 case DISC:
232 ax25_send_control(ax25, DM, pf, C_RESPONSE);
233 break;
234
235 case UA:
236 if (pf || dama) {
237 if (dama) ax25_dama_on(ax25); /* bke */
238
239 ax25_calculate_rtt(ax25);
240 ax25->t1timer = 0;
241 ax25->t3timer = ax25->t3;
242 ax25->idletimer = ax25->idle;
243 ax25->vs = 0;
244 ax25->va = 0;
245 ax25->vr = 0;
246 ax25->state = AX25_STATE_3;
247 ax25->n2count = 0;
248 ax25->dama_slave = dama; /* bke */
249
250 if (ax25->sk != NULL) {
251 ax25->sk->state = TCP_ESTABLISHED;
252 /* For WAIT_SABM connections we will produce an accept ready socket here */
253 if (!ax25->sk->dead)
254 ax25->sk->state_change(ax25->sk);
255 }
256 }
257 break;
258
259 case DM:
260 if (pf) {
261 if (ax25->modulus == MODULUS) {
262 ax25_clear_queues(ax25);
263 ax25->state = AX25_STATE_0;
264 if (ax25->sk != NULL) {
265 ax25->sk->state = TCP_CLOSE;
266 ax25->sk->err = ECONNREFUSED;
267 if (!ax25->sk->dead)
268 ax25->sk->state_change(ax25->sk);
269 ax25->sk->dead = 1;
270 }
271 } else {
272 ax25->modulus = MODULUS;
273 ax25->window = ax25_dev_get_value(ax25->device, AX25_VALUES_WINDOW);
274 }
275 }
276 break;
277
278 default:
279 if (dama && pf) /* dl1bke 960116 */
280 ax25_send_control(ax25, SABM, POLLON, C_COMMAND);
281 break;
282 }
283
284 return 0;
285 }
286
287 /*
288 * State machine for state 2, Awaiting Release State.
289 * The handling of the timer(s) is in file ax25_timer.c
290 * Handling of state 0 and connection release is in ax25.c.
291 */
292 static int ax25_state2_machine(ax25_cb *ax25, struct sk_buff *skb, int frametype, int pf, int type)
/* */
293 {
294 switch (frametype) {
295 case SABM:
296 case SABME:
297 ax25_send_control(ax25, DM, pf, C_RESPONSE);
298 if (ax25->dama_slave)
299 ax25_send_control(ax25, DISC, POLLON, C_COMMAND);
300 break;
301
302 case DISC:
303 ax25_send_control(ax25, UA, pf, C_RESPONSE);
304 if (ax25->dama_slave) {
305 ax25->state = AX25_STATE_0;
306 ax25_dama_off(ax25);
307
308 if (ax25->sk != NULL) {
309 ax25->sk->state = TCP_CLOSE;
310 ax25->sk->err = 0;
311 if (!ax25->sk->dead)
312 ax25->sk->state_change(ax25->sk);
313 ax25->sk->dead = 1;
314 }
315 }
316 break;
317
318 case UA:
319 if (pf) {
320 ax25->state = AX25_STATE_0;
321 ax25_dama_off(ax25);
322
323 if (ax25->sk != NULL) {
324 ax25->sk->state = TCP_CLOSE;
325 ax25->sk->err = 0;
326 if (!ax25->sk->dead)
327 ax25->sk->state_change(ax25->sk);
328 ax25->sk->dead = 1;
329 }
330 }
331 break;
332
333 case DM:
334 if (pf) {
335 ax25->state = AX25_STATE_0;
336 ax25_dama_off(ax25);
337
338 if (ax25->sk != NULL) {
339 ax25->sk->state = TCP_CLOSE;
340 ax25->sk->err = 0;
341 if (!ax25->sk->dead)
342 ax25->sk->state_change(ax25->sk);
343 ax25->sk->dead = 1;
344 }
345 }
346 break;
347
348 case I:
349 case REJ:
350 case RNR:
351 case RR:
352 if (pf) {
353 if (ax25->dama_slave)
354 ax25_send_control(ax25, DISC, POLLON, C_COMMAND);
355 else
356 ax25_send_control(ax25, DM, POLLON, C_RESPONSE);
357 }
358 break;
359
360 default:
361 break;
362 }
363
364 return 0;
365 }
366
367 /*
368 * State machine for state 3, Connected State.
369 * The handling of the timer(s) is in file ax25_timer.c
370 * Handling of state 0 and connection release is in ax25.c.
371 */
372 static int ax25_state3_machine(ax25_cb *ax25, struct sk_buff *skb, int frametype, int ns, int nr, int pf, int type, int dama)
/* */
373 {
374 int queued = 0;
375
376 switch (frametype) {
377 case SABM:
378 if (dama) ax25_dama_on(ax25);
379
380 ax25->modulus = MODULUS;
381 ax25->window = ax25_dev_get_value(ax25->device, AX25_VALUES_WINDOW);
382 ax25_send_control(ax25, UA, pf, C_RESPONSE);
383 ax25->condition = 0x00;
384 ax25->t1timer = 0;
385 ax25->t3timer = ax25->t3;
386 ax25->idletimer = ax25->idle;
387 ax25->vs = 0;
388 ax25->va = 0;
389 ax25->vr = 0;
390 ax25->dama_slave = dama;
391 break;
392
393 case SABME:
394 if (dama) ax25_dama_on(ax25);
395
396 ax25->modulus = EMODULUS;
397 ax25->window = ax25_dev_get_value(ax25->device, AX25_VALUES_EWINDOW);
398 ax25_send_control(ax25, UA, pf, C_RESPONSE);
399 ax25->condition = 0x00;
400 ax25->t1timer = 0;
401 ax25->t3timer = ax25->t3;
402 ax25->idletimer = ax25->idle;
403 ax25->vs = 0;
404 ax25->va = 0;
405 ax25->vr = 0;
406 ax25->dama_slave = dama;
407 break;
408
409 case DISC:
410 ax25_clear_queues(ax25);
411 ax25_send_control(ax25, UA, pf, C_RESPONSE);
412 ax25->t3timer = 0;
413 ax25->state = AX25_STATE_0;
414 ax25_dama_off(ax25);
415
416 if (ax25->sk != NULL) {
417 ax25->sk->state = TCP_CLOSE;
418 ax25->sk->err = 0;
419 if (!ax25->sk->dead)
420 ax25->sk->state_change(ax25->sk);
421 ax25->sk->dead = 1;
422 }
423 break;
424
425 case DM:
426 ax25_clear_queues(ax25);
427 ax25->t3timer = 0;
428 ax25->state = AX25_STATE_0;
429 ax25_dama_off(ax25);
430 if (ax25->sk) {
431 ax25->sk->state = TCP_CLOSE;
432 ax25->sk->err = ECONNRESET;
433 if (!ax25->sk->dead)
434 ax25->sk->state_change(ax25->sk);
435 ax25->sk->dead = 1;
436 }
437 break;
438
439 case RNR:
440 ax25->condition |= PEER_RX_BUSY_CONDITION;
441 ax25_check_need_response(ax25, type, pf);
442 if (ax25_validate_nr(ax25, nr)) {
443 ax25_check_iframes_acked(ax25, nr);
444 dama_check_need_response(ax25, type, pf);
445 } else {
446 ax25_nr_error_recovery(ax25);
447 ax25->state = AX25_STATE_1;
448 }
449 break;
450
451 case RR:
452 ax25->condition &= ~PEER_RX_BUSY_CONDITION;
453 ax25_check_need_response(ax25, type, pf);
454 if (ax25_validate_nr(ax25, nr)) {
455 ax25_check_iframes_acked(ax25, nr);
456 dama_check_need_response(ax25, type, pf);
457 } else {
458 ax25_nr_error_recovery(ax25);
459 ax25->state = AX25_STATE_1;
460 }
461 break;
462
463 case REJ:
464 ax25->condition &= ~PEER_RX_BUSY_CONDITION;
465 ax25_check_need_response(ax25, type, pf);
466 if (ax25_validate_nr(ax25, nr)) {
467 ax25_frames_acked(ax25, nr);
468 ax25_calculate_rtt(ax25);
469 ax25->t1timer = 0;
470 ax25->t3timer = ax25->t3;
471 ax25_requeue_frames(ax25);
472 dama_check_need_response(ax25, type, pf);
473 } else {
474 ax25_nr_error_recovery(ax25);
475 ax25->state = AX25_STATE_1;
476 }
477 break;
478
479 case I:
480 #ifndef AX25_BROKEN_NETMAC
481 if (type != C_COMMAND)
482 break;
483 #endif
484 if (!ax25_validate_nr(ax25, nr)) {
485 ax25_nr_error_recovery(ax25);
486 ax25->state = AX25_STATE_1;
487 break;
488 }
489 if (ax25->condition & PEER_RX_BUSY_CONDITION) {
490 ax25_frames_acked(ax25, nr);
491 } else {
492 ax25_check_iframes_acked(ax25, nr);
493 }
494 if (ax25->condition & OWN_RX_BUSY_CONDITION) {
495 if (pf) {
496 if (ax25->dama_slave) /* dl1bke 960114 */
497 dama_enquiry_response(ax25);
498 else
499 ax25_enquiry_response(ax25);
500 }
501 break;
502 }
503 if (ns == ax25->vr) {
504 queued = ax25_rx_iframe(ax25, skb);
505 if (ax25->condition & OWN_RX_BUSY_CONDITION) {
506 if (pf) {
507 if (ax25->dama_slave) /* dl1bke 960114 */
508 dama_enquiry_response(ax25);
509 else
510 ax25_enquiry_response(ax25);
511 }
512 break;
513 }
514 ax25->vr = (ax25->vr + 1) % ax25->modulus;
515 ax25->condition &= ~REJECT_CONDITION;
516 if (pf) {
517 if (ax25->dama_slave) /* dl1bke 960114 */
518 dama_enquiry_response(ax25);
519 else
520 ax25_enquiry_response(ax25);
521 } else {
522 if (!(ax25->condition & ACK_PENDING_CONDITION)) {
523 ax25->t2timer = ax25->t2;
524 ax25->condition |= ACK_PENDING_CONDITION;
525 }
526 }
527 } else {
528 if (ax25->condition & REJECT_CONDITION) {
529 if (pf) {
530 if (ax25->dama_slave) /* dl1bke 960114 */
531 dama_enquiry_response(ax25);
532 else
533 ax25_enquiry_response(ax25);
534 }
535 } else {
536 ax25->condition |= REJECT_CONDITION;
537 if (ax25->dama_slave) /* dl1bke 960114 */
538 dama_enquiry_response(ax25);
539 else
540 ax25_send_control(ax25, REJ, pf, C_RESPONSE);
541 ax25->condition &= ~ACK_PENDING_CONDITION;
542 }
543 }
544 break;
545
546 case FRMR:
547 case ILLEGAL:
548 ax25_establish_data_link(ax25);
549 ax25->state = AX25_STATE_1;
550 break;
551
552 default:
553 break;
554 }
555
556 return queued;
557 }
558
559 /*
560 * State machine for state 4, Timer Recovery State.
561 * The handling of the timer(s) is in file ax25_timer.c
562 * Handling of state 0 and connection release is in ax25.c.
563 */
564 static int ax25_state4_machine(ax25_cb *ax25, struct sk_buff *skb, int frametype, int ns, int nr, int pf, int type, int dama)
/* */
565 {
566 int queued = 0;
567
568 switch (frametype) {
569 case SABM:
570 if (dama) ax25_dama_on(ax25);
571
572 ax25->dama_slave = dama;
573 ax25->modulus = MODULUS;
574 ax25->window = ax25_dev_get_value(ax25->device, AX25_VALUES_WINDOW);
575 ax25_send_control(ax25, UA, pf, C_RESPONSE);
576 ax25->condition = 0x00;
577 ax25->t1timer = 0;
578 ax25->t3timer = ax25->t3;
579 ax25->idletimer = ax25->idle;
580 ax25->vs = 0;
581 ax25->va = 0;
582 ax25->vr = 0;
583 ax25->state = AX25_STATE_3;
584 ax25->n2count = 0;
585 break;
586
587 case SABME:
588 if (dama) ax25_dama_on(ax25);
589
590 ax25->dama_slave = dama;
591 ax25->modulus = EMODULUS;
592 ax25->window = ax25_dev_get_value(ax25->device, AX25_VALUES_EWINDOW);
593 ax25_send_control(ax25, UA, pf, C_RESPONSE);
594 ax25->condition = 0x00;
595 ax25->t1timer = 0;
596 ax25->t3timer = ax25->t3;
597 ax25->idletimer = ax25->idle;
598 ax25->vs = 0;
599 ax25->va = 0;
600 ax25->vr = 0;
601 ax25->state = AX25_STATE_3;
602 ax25->n2count = 0;
603 break;
604
605 case DISC:
606 ax25_clear_queues(ax25);
607 ax25_send_control(ax25, UA, pf, C_RESPONSE);
608 ax25->t3timer = 0;
609 ax25->state = AX25_STATE_0;
610 ax25_dama_off(ax25);
611
612 if (ax25->sk != NULL) {
613 ax25->sk->state = TCP_CLOSE;
614 ax25->sk->err = 0;
615 if (!ax25->sk->dead)
616 ax25->sk->state_change(ax25->sk);
617 ax25->sk->dead = 1;
618 }
619 break;
620
621 case DM:
622 ax25_clear_queues(ax25);
623 ax25->t3timer = 0;
624 ax25->state = AX25_STATE_0;
625 ax25_dama_off(ax25);
626
627 if (ax25->sk != NULL) {
628 ax25->sk->state = TCP_CLOSE;
629 ax25->sk->err = ECONNRESET;
630 if (!ax25->sk->dead)
631 ax25->sk->state_change(ax25->sk);
632 ax25->sk->dead = 1;
633 }
634 break;
635
636 case RNR:
637 ax25->condition |= PEER_RX_BUSY_CONDITION;
638 if (type == C_RESPONSE && pf) {
639 ax25->t1timer = 0;
640 if (ax25_validate_nr(ax25, nr)) {
641 ax25_frames_acked(ax25, nr);
642 if (ax25->vs == ax25->va) {
643 ax25->t3timer = ax25->t3;
644 ax25->n2count = 0;
645 ax25->state = AX25_STATE_3;
646 }
647 } else {
648 ax25_nr_error_recovery(ax25);
649 ax25->state = AX25_STATE_1;
650 }
651 break;
652 }
653
654 ax25_check_need_response(ax25, type, pf);
655 if (ax25_validate_nr(ax25, nr)) {
656 ax25_frames_acked(ax25, nr);
657 dama_check_need_response(ax25, type, pf);
658 } else {
659 ax25_nr_error_recovery(ax25);
660 ax25->state = AX25_STATE_1;
661 }
662 break;
663
664 case RR:
665 ax25->condition &= ~PEER_RX_BUSY_CONDITION;
666 if ( pf && (type == C_RESPONSE || (ax25->dama_slave && type == C_COMMAND)) ) {
667 ax25->t1timer = 0;
668 if (ax25_validate_nr(ax25, nr)) {
669 ax25_frames_acked(ax25, nr);
670 if (ax25->vs == ax25->va) {
671 ax25->t3timer = ax25->t3;
672 ax25->n2count = 0;
673 ax25->state = AX25_STATE_3;
674 } else {
675 ax25_requeue_frames(ax25);
676 }
677 dama_check_need_response(ax25, type, pf);
678 } else {
679 ax25_nr_error_recovery(ax25);
680 ax25->state = AX25_STATE_1;
681 }
682 break;
683 }
684
685 ax25_check_need_response(ax25, type, pf);
686 if (ax25_validate_nr(ax25, nr)) {
687 ax25_frames_acked(ax25, nr);
688 dama_check_need_response(ax25, type, pf);
689 } else {
690 ax25_nr_error_recovery(ax25);
691 ax25->state = AX25_STATE_1;
692 }
693 break;
694
695 case REJ:
696 ax25->condition &= ~PEER_RX_BUSY_CONDITION;
697 if ( pf && (type == C_RESPONSE || (ax25->dama_slave && type == C_COMMAND)) ) {
698 ax25->t1timer = 0;
699 if (ax25_validate_nr(ax25, nr)) {
700 ax25_frames_acked(ax25, nr);
701 if (ax25->vs == ax25->va) {
702 ax25->t3timer = ax25->t3;
703 ax25->n2count = 0;
704 ax25->state = AX25_STATE_3;
705 } else {
706 ax25_requeue_frames(ax25);
707 }
708 dama_check_need_response(ax25, type, pf);
709 } else {
710 ax25_nr_error_recovery(ax25);
711 ax25->state = AX25_STATE_1;
712 }
713 break;
714 }
715
716 ax25_check_need_response(ax25, type, pf);
717 if (ax25_validate_nr(ax25, nr)) {
718 ax25_frames_acked(ax25, nr);
719 if(ax25->vs != ax25->va) {
720 ax25_requeue_frames(ax25);
721 }
722 dama_check_need_response(ax25, type, pf);
723 } else {
724 ax25_nr_error_recovery(ax25);
725 ax25->state = AX25_STATE_1;
726 }
727 break;
728
729 case I:
730 #ifndef AX25_BROKEN_NETMAC
731 if (type != C_COMMAND)
732 break;
733 #endif
734 if (!ax25_validate_nr(ax25, nr)) {
735 ax25_nr_error_recovery(ax25);
736 ax25->state = AX25_STATE_1;
737 break;
738 }
739 ax25_frames_acked(ax25, nr);
740 if (ax25->condition & OWN_RX_BUSY_CONDITION) {
741 if (pf) { /* dl1bke 960114 */
742 if (ax25->dama_slave)
743 ax25_enquiry_response(ax25);
744 else
745 dama_enquiry_response(ax25);
746 }
747 break;
748 }
749 if (ns == ax25->vr) {
750 queued = ax25_rx_iframe(ax25, skb);
751 if (ax25->condition & OWN_RX_BUSY_CONDITION) {
752 if (pf) { /* dl1bke 960114 */
753 if (ax25->dama_slave)
754 dama_enquiry_response(ax25);
755 else
756 ax25_enquiry_response(ax25);
757 }
758 break;
759 }
760 ax25->vr = (ax25->vr + 1) % ax25->modulus;
761 ax25->condition &= ~REJECT_CONDITION;
762 if (pf) {
763 if (ax25->dama_slave) /* dl1bke 960114 */
764 dama_enquiry_response(ax25);
765 else
766 ax25_enquiry_response(ax25);
767 } else {
768 if (!(ax25->condition & ACK_PENDING_CONDITION)) {
769 ax25->t2timer = ax25->t2;
770 ax25->condition |= ACK_PENDING_CONDITION;
771 }
772 }
773 } else {
774 if (ax25->condition & REJECT_CONDITION) {
775 if (pf) { /* dl1bke 960114 */
776 if (ax25->dama_slave)
777 dama_enquiry_response(ax25);
778 else
779 ax25_enquiry_response(ax25);
780 }
781 } else {
782 ax25->condition |= REJECT_CONDITION;
783 if (ax25->dama_slave) /* dl1bke 960114 */
784 dama_enquiry_response(ax25);
785 else
786 ax25_send_control(ax25, REJ, pf, C_RESPONSE);
787 ax25->condition &= ~ACK_PENDING_CONDITION;
788 }
789 }
790 break;
791
792 case FRMR:
793 case ILLEGAL:
794 ax25_establish_data_link(ax25);
795 ax25->state = AX25_STATE_1;
796 break;
797
798 default:
799 break;
800 }
801
802 return queued;
803 }
804
805 /*
806 * Higher level upcall for a LAPB frame
807 */
808 int ax25_process_rx_frame(ax25_cb *ax25, struct sk_buff *skb, int type, int dama)
/* ![[last]](../icons/n_last.png)
*/
809 {
810 int queued = 0, frametype, ns, nr, pf;
811
812 if (ax25->sk != NULL && ax25->state == AX25_STATE_0 && ax25->sk->dead)
813 return queued;
814
815 if (ax25->state != AX25_STATE_1 && ax25->state != AX25_STATE_2 &&
816 ax25->state != AX25_STATE_3 && ax25->state != AX25_STATE_4) {
817 printk("ax25_process_rx_frame: frame received - state = %d\n", ax25->state);
818 return queued;
819 }
820
821 del_timer(&ax25->timer);
822
823 frametype = ax25_decode(ax25, skb, &ns, &nr, &pf);
824
825 switch (ax25->state) {
826 case AX25_STATE_1:
827 queued = ax25_state1_machine(ax25, skb, frametype, pf, type, dama);
828 break;
829 case AX25_STATE_2:
830 queued = ax25_state2_machine(ax25, skb, frametype, pf, type);
831 break;
832 case AX25_STATE_3:
833 queued = ax25_state3_machine(ax25, skb, frametype, ns, nr, pf, type, dama);
834 break;
835 case AX25_STATE_4:
836 queued = ax25_state4_machine(ax25, skb, frametype, ns, nr, pf, type, dama);
837 break;
838 }
839
840 ax25_set_timer(ax25);
841
842 return queued;
843 }
844
845 #endif
![[bottom]](../icons/n_bottom.png){kind=icon}
*/