xref: /openbmc/linux/net/llc/llc_c_ac.c (revision d5cb9783536a41df9f9cba5b0a1d78047ed787f7)
1 /*
2  * llc_c_ac.c - actions performed during connection state transition.
3  *
4  * Description:
5  *   Functions in this module are implementation of connection component actions
6  *   Details of actions can be found in IEEE-802.2 standard document.
7  *   All functions have one connection and one event as input argument. All of
8  *   them return 0 On success and 1 otherwise.
9  *
10  * Copyright (c) 1997 by Procom Technology, Inc.
11  * 		 2001-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
12  *
13  * This program can be redistributed or modified under the terms of the
14  * GNU General Public License as published by the Free Software Foundation.
15  * This program is distributed without any warranty or implied warranty
16  * of merchantability or fitness for a particular purpose.
17  *
18  * See the GNU General Public License for more details.
19  */
20 #include <linux/netdevice.h>
21 #include <net/llc_conn.h>
22 #include <net/llc_sap.h>
23 #include <net/sock.h>
24 #include <net/llc_c_ev.h>
25 #include <net/llc_c_ac.h>
26 #include <net/llc_c_st.h>
27 #include <net/llc_pdu.h>
28 #include <net/llc.h>
29 
30 #include "llc_output.h"
31 
32 static int llc_conn_ac_inc_vs_by_1(struct sock *sk, struct sk_buff *skb);
33 static void llc_process_tmr_ev(struct sock *sk, struct sk_buff *skb);
34 static int llc_conn_ac_data_confirm(struct sock *sk, struct sk_buff *ev);
35 
36 static int llc_conn_ac_inc_npta_value(struct sock *sk, struct sk_buff *skb);
37 
38 static int llc_conn_ac_send_rr_rsp_f_set_ackpf(struct sock *sk,
39 					       struct sk_buff *skb);
40 
41 static int llc_conn_ac_set_p_flag_1(struct sock *sk, struct sk_buff *skb);
42 
43 #define INCORRECT 0
44 
45 int llc_conn_ac_clear_remote_busy(struct sock *sk, struct sk_buff *skb)
46 {
47 	struct llc_sock *llc = llc_sk(sk);
48 
49 	if (llc->remote_busy_flag) {
50 		u8 nr;
51 		struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
52 
53 		llc->remote_busy_flag = 0;
54 		del_timer(&llc->busy_state_timer.timer);
55 		nr = LLC_I_GET_NR(pdu);
56 		llc_conn_resend_i_pdu_as_cmd(sk, nr, 0);
57 	}
58 	return 0;
59 }
60 
61 int llc_conn_ac_conn_ind(struct sock *sk, struct sk_buff *skb)
62 {
63 	struct llc_conn_state_ev *ev = llc_conn_ev(skb);
64 
65 	ev->ind_prim = LLC_CONN_PRIM;
66 	return 0;
67 }
68 
69 int llc_conn_ac_conn_confirm(struct sock *sk, struct sk_buff *skb)
70 {
71 	struct llc_conn_state_ev *ev = llc_conn_ev(skb);
72 
73 	ev->cfm_prim = LLC_CONN_PRIM;
74 	return 0;
75 }
76 
77 static int llc_conn_ac_data_confirm(struct sock *sk, struct sk_buff *skb)
78 {
79 	struct llc_conn_state_ev *ev = llc_conn_ev(skb);
80 
81 	ev->cfm_prim = LLC_DATA_PRIM;
82 	return 0;
83 }
84 
85 int llc_conn_ac_data_ind(struct sock *sk, struct sk_buff *skb)
86 {
87 	llc_conn_rtn_pdu(sk, skb);
88 	return 0;
89 }
90 
91 int llc_conn_ac_disc_ind(struct sock *sk, struct sk_buff *skb)
92 {
93 	struct llc_conn_state_ev *ev = llc_conn_ev(skb);
94 	u8 reason = 0;
95 	int rc = 0;
96 
97 	if (ev->type == LLC_CONN_EV_TYPE_PDU) {
98 		struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
99 
100 		if (LLC_PDU_IS_RSP(pdu) &&
101 		    LLC_PDU_TYPE_IS_U(pdu) &&
102 		    LLC_U_PDU_RSP(pdu) == LLC_2_PDU_RSP_DM)
103 			reason = LLC_DISC_REASON_RX_DM_RSP_PDU;
104 		else if (LLC_PDU_IS_CMD(pdu) &&
105 			   LLC_PDU_TYPE_IS_U(pdu) &&
106 			   LLC_U_PDU_CMD(pdu) == LLC_2_PDU_CMD_DISC)
107 			reason = LLC_DISC_REASON_RX_DISC_CMD_PDU;
108 	} else if (ev->type == LLC_CONN_EV_TYPE_ACK_TMR)
109 		reason = LLC_DISC_REASON_ACK_TMR_EXP;
110 	else
111 		rc = -EINVAL;
112 	if (!rc) {
113 		ev->reason   = reason;
114 		ev->ind_prim = LLC_DISC_PRIM;
115 	}
116 	return rc;
117 }
118 
119 int llc_conn_ac_disc_confirm(struct sock *sk, struct sk_buff *skb)
120 {
121 	struct llc_conn_state_ev *ev = llc_conn_ev(skb);
122 
123 	ev->reason   = ev->status;
124 	ev->cfm_prim = LLC_DISC_PRIM;
125 	return 0;
126 }
127 
128 int llc_conn_ac_rst_ind(struct sock *sk, struct sk_buff *skb)
129 {
130 	u8 reason = 0;
131 	int rc = 1;
132 	struct llc_conn_state_ev *ev = llc_conn_ev(skb);
133 	struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
134 	struct llc_sock *llc = llc_sk(sk);
135 
136 	switch (ev->type) {
137 	case LLC_CONN_EV_TYPE_PDU:
138 		if (LLC_PDU_IS_RSP(pdu) &&
139 		    LLC_PDU_TYPE_IS_U(pdu) &&
140 		    LLC_U_PDU_RSP(pdu) == LLC_2_PDU_RSP_FRMR) {
141 			reason = LLC_RESET_REASON_LOCAL;
142 			rc = 0;
143 		} else if (LLC_PDU_IS_CMD(pdu) &&
144 			   LLC_PDU_TYPE_IS_U(pdu) &&
145 			   LLC_U_PDU_CMD(pdu) == LLC_2_PDU_CMD_SABME) {
146 			reason = LLC_RESET_REASON_REMOTE;
147 			rc = 0;
148 		}
149 		break;
150 	case LLC_CONN_EV_TYPE_ACK_TMR:
151 	case LLC_CONN_EV_TYPE_P_TMR:
152 	case LLC_CONN_EV_TYPE_REJ_TMR:
153 	case LLC_CONN_EV_TYPE_BUSY_TMR:
154 		if (llc->retry_count > llc->n2) {
155 			reason = LLC_RESET_REASON_LOCAL;
156 			rc = 0;
157 		}
158 		break;
159 	}
160 	if (!rc) {
161 		ev->reason   = reason;
162 		ev->ind_prim = LLC_RESET_PRIM;
163 	}
164 	return rc;
165 }
166 
167 int llc_conn_ac_rst_confirm(struct sock *sk, struct sk_buff *skb)
168 {
169 	struct llc_conn_state_ev *ev = llc_conn_ev(skb);
170 
171 	ev->reason   = 0;
172 	ev->cfm_prim = LLC_RESET_PRIM;
173 	return 0;
174 }
175 
176 int llc_conn_ac_clear_remote_busy_if_f_eq_1(struct sock *sk,
177 					    struct sk_buff *skb)
178 {
179 	struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
180 
181 	if (LLC_PDU_IS_RSP(pdu) &&
182 	    LLC_PDU_TYPE_IS_I(pdu) &&
183 	    LLC_I_PF_IS_1(pdu) && llc_sk(sk)->ack_pf)
184 		llc_conn_ac_clear_remote_busy(sk, skb);
185 	return 0;
186 }
187 
188 int llc_conn_ac_stop_rej_tmr_if_data_flag_eq_2(struct sock *sk,
189 					       struct sk_buff *skb)
190 {
191 	struct llc_sock *llc = llc_sk(sk);
192 
193 	if (llc->data_flag == 2)
194 		del_timer(&llc->rej_sent_timer.timer);
195 	return 0;
196 }
197 
198 int llc_conn_ac_send_disc_cmd_p_set_x(struct sock *sk, struct sk_buff *skb)
199 {
200 	int rc = -ENOBUFS;
201 	struct llc_sock *llc = llc_sk(sk);
202 	struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
203 
204 	if (nskb) {
205 		struct llc_sap *sap = llc->sap;
206 
207 		llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, sap->laddr.lsap,
208 				    llc->daddr.lsap, LLC_PDU_CMD);
209 		llc_pdu_init_as_disc_cmd(nskb, 1);
210 		rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
211 		if (unlikely(rc))
212 			goto free;
213 		llc_conn_send_pdu(sk, nskb);
214 		llc_conn_ac_set_p_flag_1(sk, skb);
215 	}
216 out:
217 	return rc;
218 free:
219 	kfree_skb(nskb);
220 	goto out;
221 }
222 
223 int llc_conn_ac_send_dm_rsp_f_set_p(struct sock *sk, struct sk_buff *skb)
224 {
225 	int rc = -ENOBUFS;
226 	struct llc_sock *llc = llc_sk(sk);
227 	struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
228 
229 	if (nskb) {
230 		struct llc_sap *sap = llc->sap;
231 		u8 f_bit;
232 
233 		llc_pdu_decode_pf_bit(skb, &f_bit);
234 		llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, sap->laddr.lsap,
235 				    llc->daddr.lsap, LLC_PDU_RSP);
236 		llc_pdu_init_as_dm_rsp(nskb, f_bit);
237 		rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
238 		if (unlikely(rc))
239 			goto free;
240 		llc_conn_send_pdu(sk, nskb);
241 	}
242 out:
243 	return rc;
244 free:
245 	kfree_skb(nskb);
246 	goto out;
247 }
248 
249 int llc_conn_ac_send_dm_rsp_f_set_1(struct sock *sk, struct sk_buff *skb)
250 {
251 	int rc = -ENOBUFS;
252 	struct llc_sock *llc = llc_sk(sk);
253 	struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
254 
255 	if (nskb) {
256 		struct llc_sap *sap = llc->sap;
257 
258 		llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, sap->laddr.lsap,
259 				    llc->daddr.lsap, LLC_PDU_RSP);
260 		llc_pdu_init_as_dm_rsp(nskb, 1);
261 		rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
262 		if (unlikely(rc))
263 			goto free;
264 		llc_conn_send_pdu(sk, nskb);
265 	}
266 out:
267 	return rc;
268 free:
269 	kfree_skb(nskb);
270 	goto out;
271 }
272 
273 int llc_conn_ac_send_frmr_rsp_f_set_x(struct sock *sk, struct sk_buff *skb)
274 {
275 	u8 f_bit;
276 	int rc = -ENOBUFS;
277 	struct sk_buff *nskb;
278 	struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
279 	struct llc_sock *llc = llc_sk(sk);
280 
281 	llc->rx_pdu_hdr = *((u32 *)pdu);
282 	if (LLC_PDU_IS_CMD(pdu))
283 		llc_pdu_decode_pf_bit(skb, &f_bit);
284 	else
285 		f_bit = 0;
286 	nskb = llc_alloc_frame(sk, llc->dev);
287 	if (nskb) {
288 		struct llc_sap *sap = llc->sap;
289 
290 		llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, sap->laddr.lsap,
291 				    llc->daddr.lsap, LLC_PDU_RSP);
292 		llc_pdu_init_as_frmr_rsp(nskb, pdu, f_bit, llc->vS,
293 					 llc->vR, INCORRECT);
294 		rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
295 		if (unlikely(rc))
296 			goto free;
297 		llc_conn_send_pdu(sk, nskb);
298 	}
299 out:
300 	return rc;
301 free:
302 	kfree_skb(nskb);
303 	goto out;
304 }
305 
306 int llc_conn_ac_resend_frmr_rsp_f_set_0(struct sock *sk, struct sk_buff *skb)
307 {
308 	int rc = -ENOBUFS;
309 	struct llc_sock *llc = llc_sk(sk);
310 	struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
311 
312 	if (nskb) {
313 		struct llc_sap *sap = llc->sap;
314 		struct llc_pdu_sn *pdu = (struct llc_pdu_sn *)&llc->rx_pdu_hdr;
315 
316 		llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, sap->laddr.lsap,
317 				    llc->daddr.lsap, LLC_PDU_RSP);
318 		llc_pdu_init_as_frmr_rsp(nskb, pdu, 0, llc->vS,
319 					 llc->vR, INCORRECT);
320 		rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
321 		if (unlikely(rc))
322 			goto free;
323 		llc_conn_send_pdu(sk, nskb);
324 	}
325 out:
326 	return rc;
327 free:
328 	kfree_skb(nskb);
329 	goto out;
330 }
331 
332 int llc_conn_ac_resend_frmr_rsp_f_set_p(struct sock *sk, struct sk_buff *skb)
333 {
334 	u8 f_bit;
335 	int rc = -ENOBUFS;
336 	struct sk_buff *nskb;
337 	struct llc_sock *llc = llc_sk(sk);
338 
339 	llc_pdu_decode_pf_bit(skb, &f_bit);
340 	nskb = llc_alloc_frame(sk, llc->dev);
341 	if (nskb) {
342 		struct llc_sap *sap = llc->sap;
343 		struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
344 
345 		llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, sap->laddr.lsap,
346 				    llc->daddr.lsap, LLC_PDU_RSP);
347 		llc_pdu_init_as_frmr_rsp(nskb, pdu, f_bit, llc->vS,
348 					 llc->vR, INCORRECT);
349 		rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
350 		if (unlikely(rc))
351 			goto free;
352 		llc_conn_send_pdu(sk, nskb);
353 	}
354 out:
355 	return rc;
356 free:
357 	kfree_skb(nskb);
358 	goto out;
359 }
360 
361 int llc_conn_ac_send_i_cmd_p_set_1(struct sock *sk, struct sk_buff *skb)
362 {
363 	int rc;
364 	struct llc_sock *llc = llc_sk(sk);
365 	struct llc_sap *sap = llc->sap;
366 
367 	llc_pdu_header_init(skb, LLC_PDU_TYPE_I, sap->laddr.lsap,
368 			    llc->daddr.lsap, LLC_PDU_CMD);
369 	llc_pdu_init_as_i_cmd(skb, 1, llc->vS, llc->vR);
370 	rc = llc_mac_hdr_init(skb, llc->dev->dev_addr, llc->daddr.mac);
371 	if (likely(!rc)) {
372 		llc_conn_send_pdu(sk, skb);
373 		llc_conn_ac_inc_vs_by_1(sk, skb);
374 	}
375 	return rc;
376 }
377 
378 static int llc_conn_ac_send_i_cmd_p_set_0(struct sock *sk, struct sk_buff *skb)
379 {
380 	int rc;
381 	struct llc_sock *llc = llc_sk(sk);
382 	struct llc_sap *sap = llc->sap;
383 
384 	llc_pdu_header_init(skb, LLC_PDU_TYPE_I, sap->laddr.lsap,
385 			    llc->daddr.lsap, LLC_PDU_CMD);
386 	llc_pdu_init_as_i_cmd(skb, 0, llc->vS, llc->vR);
387 	rc = llc_mac_hdr_init(skb, llc->dev->dev_addr, llc->daddr.mac);
388 	if (likely(!rc)) {
389 		llc_conn_send_pdu(sk, skb);
390 		llc_conn_ac_inc_vs_by_1(sk, skb);
391 	}
392 	return rc;
393 }
394 
395 int llc_conn_ac_send_i_xxx_x_set_0(struct sock *sk, struct sk_buff *skb)
396 {
397 	int rc;
398 	struct llc_sock *llc = llc_sk(sk);
399 	struct llc_sap *sap = llc->sap;
400 
401 	llc_pdu_header_init(skb, LLC_PDU_TYPE_I, sap->laddr.lsap,
402 			    llc->daddr.lsap, LLC_PDU_CMD);
403 	llc_pdu_init_as_i_cmd(skb, 0, llc->vS, llc->vR);
404 	rc = llc_mac_hdr_init(skb, llc->dev->dev_addr, llc->daddr.mac);
405 	if (likely(!rc)) {
406 		llc_conn_send_pdu(sk, skb);
407 		llc_conn_ac_inc_vs_by_1(sk, skb);
408 	}
409 	return 0;
410 }
411 
412 int llc_conn_ac_resend_i_xxx_x_set_0(struct sock *sk, struct sk_buff *skb)
413 {
414 	struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
415 	u8 nr = LLC_I_GET_NR(pdu);
416 
417 	llc_conn_resend_i_pdu_as_cmd(sk, nr, 0);
418 	return 0;
419 }
420 
421 int llc_conn_ac_resend_i_xxx_x_set_0_or_send_rr(struct sock *sk,
422 						struct sk_buff *skb)
423 {
424 	u8 nr;
425 	struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
426 	int rc = -ENOBUFS;
427 	struct llc_sock *llc = llc_sk(sk);
428 	struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
429 
430 	if (nskb) {
431 		struct llc_sap *sap = llc->sap;
432 
433 		llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, sap->laddr.lsap,
434 				    llc->daddr.lsap, LLC_PDU_RSP);
435 		llc_pdu_init_as_rr_rsp(nskb, 0, llc->vR);
436 		rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
437 		if (likely(!rc))
438 			llc_conn_send_pdu(sk, nskb);
439 		else
440 			kfree_skb(skb);
441 	}
442 	if (rc) {
443 		nr = LLC_I_GET_NR(pdu);
444 		rc = 0;
445 		llc_conn_resend_i_pdu_as_cmd(sk, nr, 0);
446 	}
447 	return rc;
448 }
449 
450 int llc_conn_ac_resend_i_rsp_f_set_1(struct sock *sk, struct sk_buff *skb)
451 {
452 	struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
453 	u8 nr = LLC_I_GET_NR(pdu);
454 
455 	llc_conn_resend_i_pdu_as_rsp(sk, nr, 1);
456 	return 0;
457 }
458 
459 int llc_conn_ac_send_rej_cmd_p_set_1(struct sock *sk, struct sk_buff *skb)
460 {
461 	int rc = -ENOBUFS;
462 	struct llc_sock *llc = llc_sk(sk);
463 	struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
464 
465 	if (nskb) {
466 		struct llc_sap *sap = llc->sap;
467 
468 		llc_pdu_header_init(nskb, LLC_PDU_TYPE_S, sap->laddr.lsap,
469 				    llc->daddr.lsap, LLC_PDU_CMD);
470 		llc_pdu_init_as_rej_cmd(nskb, 1, llc->vR);
471 		rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
472 		if (unlikely(rc))
473 			goto free;
474 		llc_conn_send_pdu(sk, nskb);
475 	}
476 out:
477 	return rc;
478 free:
479 	kfree_skb(nskb);
480 	goto out;
481 }
482 
483 int llc_conn_ac_send_rej_rsp_f_set_1(struct sock *sk, struct sk_buff *skb)
484 {
485 	int rc = -ENOBUFS;
486 	struct llc_sock *llc = llc_sk(sk);
487 	struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
488 
489 	if (nskb) {
490 		struct llc_sap *sap = llc->sap;
491 
492 		llc_pdu_header_init(nskb, LLC_PDU_TYPE_S, sap->laddr.lsap,
493 				    llc->daddr.lsap, LLC_PDU_RSP);
494 		llc_pdu_init_as_rej_rsp(nskb, 1, llc->vR);
495 		rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
496 		if (unlikely(rc))
497 			goto free;
498 		llc_conn_send_pdu(sk, nskb);
499 	}
500 out:
501 	return rc;
502 free:
503 	kfree_skb(nskb);
504 	goto out;
505 }
506 
507 int llc_conn_ac_send_rej_xxx_x_set_0(struct sock *sk, struct sk_buff *skb)
508 {
509 	int rc = -ENOBUFS;
510 	struct llc_sock *llc = llc_sk(sk);
511 	struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
512 
513 	if (nskb) {
514 		struct llc_sap *sap = llc->sap;
515 
516 		llc_pdu_header_init(nskb, LLC_PDU_TYPE_S, sap->laddr.lsap,
517 				    llc->daddr.lsap, LLC_PDU_RSP);
518 		llc_pdu_init_as_rej_rsp(nskb, 0, llc->vR);
519 		rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
520 		if (unlikely(rc))
521 			goto free;
522 		llc_conn_send_pdu(sk, nskb);
523 	}
524 out:
525 	return rc;
526 free:
527 	kfree_skb(nskb);
528 	goto out;
529 }
530 
531 int llc_conn_ac_send_rnr_cmd_p_set_1(struct sock *sk, struct sk_buff *skb)
532 {
533 	int rc = -ENOBUFS;
534 	struct llc_sock *llc = llc_sk(sk);
535 	struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
536 
537 	if (nskb) {
538 		struct llc_sap *sap = llc->sap;
539 
540 		llc_pdu_header_init(nskb, LLC_PDU_TYPE_S, sap->laddr.lsap,
541 				    llc->daddr.lsap, LLC_PDU_CMD);
542 		llc_pdu_init_as_rnr_cmd(nskb, 1, llc->vR);
543 		rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
544 		if (unlikely(rc))
545 			goto free;
546 		llc_conn_send_pdu(sk, nskb);
547 	}
548 out:
549 	return rc;
550 free:
551 	kfree_skb(nskb);
552 	goto out;
553 }
554 
555 int llc_conn_ac_send_rnr_rsp_f_set_1(struct sock *sk, struct sk_buff *skb)
556 {
557 	int rc = -ENOBUFS;
558 	struct llc_sock *llc = llc_sk(sk);
559 	struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
560 
561 	if (nskb) {
562 		struct llc_sap *sap = llc->sap;
563 
564 		llc_pdu_header_init(nskb, LLC_PDU_TYPE_S, sap->laddr.lsap,
565 				    llc->daddr.lsap, LLC_PDU_RSP);
566 		llc_pdu_init_as_rnr_rsp(nskb, 1, llc->vR);
567 		rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
568 		if (unlikely(rc))
569 			goto free;
570 		llc_conn_send_pdu(sk, nskb);
571 	}
572 out:
573 	return rc;
574 free:
575 	kfree_skb(nskb);
576 	goto out;
577 }
578 
579 int llc_conn_ac_send_rnr_xxx_x_set_0(struct sock *sk, struct sk_buff *skb)
580 {
581 	int rc = -ENOBUFS;
582 	struct llc_sock *llc = llc_sk(sk);
583 	struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
584 
585 	if (nskb) {
586 		struct llc_sap *sap = llc->sap;
587 
588 		llc_pdu_header_init(nskb, LLC_PDU_TYPE_S, sap->laddr.lsap,
589 				    llc->daddr.lsap, LLC_PDU_RSP);
590 		llc_pdu_init_as_rnr_rsp(nskb, 0, llc->vR);
591 		rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
592 		if (unlikely(rc))
593 			goto free;
594 		llc_conn_send_pdu(sk, nskb);
595 	}
596 out:
597 	return rc;
598 free:
599 	kfree_skb(nskb);
600 	goto out;
601 }
602 
603 int llc_conn_ac_set_remote_busy(struct sock *sk, struct sk_buff *skb)
604 {
605 	struct llc_sock *llc = llc_sk(sk);
606 
607 	if (!llc->remote_busy_flag) {
608 		llc->remote_busy_flag = 1;
609 		mod_timer(&llc->busy_state_timer.timer,
610 			 jiffies + llc->busy_state_timer.expire);
611 	}
612 	return 0;
613 }
614 
615 int llc_conn_ac_opt_send_rnr_xxx_x_set_0(struct sock *sk, struct sk_buff *skb)
616 {
617 	int rc = -ENOBUFS;
618 	struct llc_sock *llc = llc_sk(sk);
619 	struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
620 
621 	if (nskb) {
622 		struct llc_sap *sap = llc->sap;
623 
624 		llc_pdu_header_init(nskb, LLC_PDU_TYPE_S, sap->laddr.lsap,
625 				    llc->daddr.lsap, LLC_PDU_RSP);
626 		llc_pdu_init_as_rnr_rsp(nskb, 0, llc->vR);
627 		rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
628 		if (unlikely(rc))
629 			goto free;
630 		llc_conn_send_pdu(sk, nskb);
631 	}
632 out:
633 	return rc;
634 free:
635 	kfree_skb(nskb);
636 	goto out;
637 }
638 
639 int llc_conn_ac_send_rr_cmd_p_set_1(struct sock *sk, struct sk_buff *skb)
640 {
641 	int rc = -ENOBUFS;
642 	struct llc_sock *llc = llc_sk(sk);
643 	struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
644 
645 	if (nskb) {
646 		struct llc_sap *sap = llc->sap;
647 
648 		llc_pdu_header_init(nskb, LLC_PDU_TYPE_S, sap->laddr.lsap,
649 				    llc->daddr.lsap, LLC_PDU_CMD);
650 		llc_pdu_init_as_rr_cmd(nskb, 1, llc->vR);
651 		rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
652 		if (unlikely(rc))
653 			goto free;
654 		llc_conn_send_pdu(sk, nskb);
655 	}
656 out:
657 	return rc;
658 free:
659 	kfree_skb(nskb);
660 	goto out;
661 }
662 
663 int llc_conn_ac_send_rr_rsp_f_set_1(struct sock *sk, struct sk_buff *skb)
664 {
665 	int rc = -ENOBUFS;
666 	struct llc_sock *llc = llc_sk(sk);
667 	struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
668 
669 	if (nskb) {
670 		struct llc_sap *sap = llc->sap;
671 		u8 f_bit = 1;
672 
673 		llc_pdu_header_init(nskb, LLC_PDU_TYPE_S, sap->laddr.lsap,
674 				    llc->daddr.lsap, LLC_PDU_RSP);
675 		llc_pdu_init_as_rr_rsp(nskb, f_bit, llc->vR);
676 		rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
677 		if (unlikely(rc))
678 			goto free;
679 		llc_conn_send_pdu(sk, nskb);
680 	}
681 out:
682 	return rc;
683 free:
684 	kfree_skb(nskb);
685 	goto out;
686 }
687 
688 int llc_conn_ac_send_ack_rsp_f_set_1(struct sock *sk, struct sk_buff *skb)
689 {
690 	int rc = -ENOBUFS;
691 	struct llc_sock *llc = llc_sk(sk);
692 	struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
693 
694 	if (nskb) {
695 		struct llc_sap *sap = llc->sap;
696 
697 		llc_pdu_header_init(nskb, LLC_PDU_TYPE_S, sap->laddr.lsap,
698 				    llc->daddr.lsap, LLC_PDU_RSP);
699 		llc_pdu_init_as_rr_rsp(nskb, 1, llc->vR);
700 		rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
701 		if (unlikely(rc))
702 			goto free;
703 		llc_conn_send_pdu(sk, nskb);
704 	}
705 out:
706 	return rc;
707 free:
708 	kfree_skb(nskb);
709 	goto out;
710 }
711 
712 int llc_conn_ac_send_rr_xxx_x_set_0(struct sock *sk, struct sk_buff *skb)
713 {
714 	int rc = -ENOBUFS;
715 	struct llc_sock *llc = llc_sk(sk);
716 	struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
717 
718 	if (nskb) {
719 		struct llc_sap *sap = llc->sap;
720 
721 		llc_pdu_header_init(nskb, LLC_PDU_TYPE_S, sap->laddr.lsap,
722 				    llc->daddr.lsap, LLC_PDU_RSP);
723 		llc_pdu_init_as_rr_rsp(nskb, 0, llc->vR);
724 		rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
725 		if (unlikely(rc))
726 			goto free;
727 		llc_conn_send_pdu(sk, nskb);
728 	}
729 out:
730 	return rc;
731 free:
732 	kfree_skb(nskb);
733 	goto out;
734 }
735 
736 int llc_conn_ac_send_ack_xxx_x_set_0(struct sock *sk, struct sk_buff *skb)
737 {
738 	int rc = -ENOBUFS;
739 	struct llc_sock *llc = llc_sk(sk);
740 	struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
741 
742 	if (nskb) {
743 		struct llc_sap *sap = llc->sap;
744 
745 		llc_pdu_header_init(nskb, LLC_PDU_TYPE_S, sap->laddr.lsap,
746 				    llc->daddr.lsap, LLC_PDU_RSP);
747 		llc_pdu_init_as_rr_rsp(nskb, 0, llc->vR);
748 		rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
749 		if (unlikely(rc))
750 			goto free;
751 		llc_conn_send_pdu(sk, nskb);
752 	}
753 out:
754 	return rc;
755 free:
756 	kfree_skb(nskb);
757 	goto out;
758 }
759 
760 void llc_conn_set_p_flag(struct sock *sk, u8 value)
761 {
762 	int state_changed = llc_sk(sk)->p_flag && !value;
763 
764 	llc_sk(sk)->p_flag = value;
765 
766 	if (state_changed)
767 		sk->sk_state_change(sk);
768 }
769 
770 int llc_conn_ac_send_sabme_cmd_p_set_x(struct sock *sk, struct sk_buff *skb)
771 {
772 	int rc = -ENOBUFS;
773 	struct llc_sock *llc = llc_sk(sk);
774 	struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
775 
776 	if (nskb) {
777 		struct llc_sap *sap = llc->sap;
778 		u8 *dmac = llc->daddr.mac;
779 
780 		if (llc->dev->flags & IFF_LOOPBACK)
781 			dmac = llc->dev->dev_addr;
782 		llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, sap->laddr.lsap,
783 				    llc->daddr.lsap, LLC_PDU_CMD);
784 		llc_pdu_init_as_sabme_cmd(nskb, 1);
785 		rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, dmac);
786 		if (unlikely(rc))
787 			goto free;
788 		llc_conn_send_pdu(sk, nskb);
789 		llc_conn_set_p_flag(sk, 1);
790 	}
791 out:
792 	return rc;
793 free:
794 	kfree_skb(nskb);
795 	goto out;
796 }
797 
798 int llc_conn_ac_send_ua_rsp_f_set_p(struct sock *sk, struct sk_buff *skb)
799 {
800 	u8 f_bit;
801 	int rc = -ENOBUFS;
802 	struct llc_sock *llc = llc_sk(sk);
803 	struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
804 
805 	llc_pdu_decode_pf_bit(skb, &f_bit);
806 	if (nskb) {
807 		struct llc_sap *sap = llc->sap;
808 
809 		nskb->dev = llc->dev;
810 		llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, sap->laddr.lsap,
811 				    llc->daddr.lsap, LLC_PDU_RSP);
812 		llc_pdu_init_as_ua_rsp(nskb, f_bit);
813 		rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
814 		if (unlikely(rc))
815 			goto free;
816 		llc_conn_send_pdu(sk, nskb);
817 	}
818 out:
819 	return rc;
820 free:
821 	kfree_skb(nskb);
822 	goto out;
823 }
824 
825 int llc_conn_ac_set_s_flag_0(struct sock *sk, struct sk_buff *skb)
826 {
827 	llc_sk(sk)->s_flag = 0;
828 	return 0;
829 }
830 
831 int llc_conn_ac_set_s_flag_1(struct sock *sk, struct sk_buff *skb)
832 {
833 	llc_sk(sk)->s_flag = 1;
834 	return 0;
835 }
836 
837 int llc_conn_ac_start_p_timer(struct sock *sk, struct sk_buff *skb)
838 {
839 	struct llc_sock *llc = llc_sk(sk);
840 
841 	llc_conn_set_p_flag(sk, 1);
842 	mod_timer(&llc->pf_cycle_timer.timer,
843 		  jiffies + llc->pf_cycle_timer.expire);
844 	return 0;
845 }
846 
847 /**
848  *	llc_conn_ac_send_ack_if_needed - check if ack is needed
849  *	@sk: current connection structure
850  *	@skb: current event
851  *
852  *	Checks number of received PDUs which have not been acknowledged, yet,
853  *	If number of them reaches to "npta"(Number of PDUs To Acknowledge) then
854  *	sends an RR response as acknowledgement for them.  Returns 0 for
855  *	success, 1 otherwise.
856  */
857 int llc_conn_ac_send_ack_if_needed(struct sock *sk, struct sk_buff *skb)
858 {
859 	u8 pf_bit;
860 	struct llc_sock *llc = llc_sk(sk);
861 
862 	llc_pdu_decode_pf_bit(skb, &pf_bit);
863 	llc->ack_pf |= pf_bit & 1;
864 	if (!llc->ack_must_be_send) {
865 		llc->first_pdu_Ns = llc->vR;
866 		llc->ack_must_be_send = 1;
867 		llc->ack_pf = pf_bit & 1;
868 	}
869 	if (((llc->vR - llc->first_pdu_Ns + 129) % 128) >= llc->npta) {
870 		llc_conn_ac_send_rr_rsp_f_set_ackpf(sk, skb);
871 		llc->ack_must_be_send	= 0;
872 		llc->ack_pf		= 0;
873 		llc_conn_ac_inc_npta_value(sk, skb);
874 	}
875 	return 0;
876 }
877 
878 /**
879  *	llc_conn_ac_rst_sendack_flag - resets ack_must_be_send flag
880  *	@sk: current connection structure
881  *	@skb: current event
882  *
883  *	This action resets ack_must_be_send flag of given connection, this flag
884  *	indicates if there is any PDU which has not been acknowledged yet.
885  *	Returns 0 for success, 1 otherwise.
886  */
887 int llc_conn_ac_rst_sendack_flag(struct sock *sk, struct sk_buff *skb)
888 {
889 	llc_sk(sk)->ack_must_be_send = llc_sk(sk)->ack_pf = 0;
890 	return 0;
891 }
892 
893 /**
894  *	llc_conn_ac_send_i_rsp_f_set_ackpf - acknowledge received PDUs
895  *	@sk: current connection structure
896  *	@skb: current event
897  *
898  *	Sends an I response PDU with f-bit set to ack_pf flag as acknowledge to
899  *	all received PDUs which have not been acknowledged, yet. ack_pf flag is
900  *	set to one if one PDU with p-bit set to one is received.  Returns 0 for
901  *	success, 1 otherwise.
902  */
903 static int llc_conn_ac_send_i_rsp_f_set_ackpf(struct sock *sk,
904 					      struct sk_buff *skb)
905 {
906 	int rc;
907 	struct llc_sock *llc = llc_sk(sk);
908 	struct llc_sap *sap = llc->sap;
909 
910 	llc_pdu_header_init(skb, LLC_PDU_TYPE_I, sap->laddr.lsap,
911 			    llc->daddr.lsap, LLC_PDU_RSP);
912 	llc_pdu_init_as_i_cmd(skb, llc->ack_pf, llc->vS, llc->vR);
913 	rc = llc_mac_hdr_init(skb, llc->dev->dev_addr, llc->daddr.mac);
914 	if (likely(!rc)) {
915 		llc_conn_send_pdu(sk, skb);
916 		llc_conn_ac_inc_vs_by_1(sk, skb);
917 	}
918 	return rc;
919 }
920 
921 /**
922  *	llc_conn_ac_send_i_as_ack - sends an I-format PDU to acknowledge rx PDUs
923  *	@sk: current connection structure.
924  *	@skb: current event.
925  *
926  *	This action sends an I-format PDU as acknowledge to received PDUs which
927  *	have not been acknowledged, yet, if there is any. By using of this
928  *	action number of acknowledgements decreases, this technic is called
929  *	piggy backing. Returns 0 for success, 1 otherwise.
930  */
931 int llc_conn_ac_send_i_as_ack(struct sock *sk, struct sk_buff *skb)
932 {
933 	struct llc_sock *llc = llc_sk(sk);
934 
935 	if (llc->ack_must_be_send) {
936 		llc_conn_ac_send_i_rsp_f_set_ackpf(sk, skb);
937 		llc->ack_must_be_send = 0 ;
938 		llc->ack_pf = 0;
939 	} else
940 		llc_conn_ac_send_i_cmd_p_set_0(sk, skb);
941 	return 0;
942 }
943 
944 /**
945  *	llc_conn_ac_send_rr_rsp_f_set_ackpf - ack all rx PDUs not yet acked
946  *	@sk: current connection structure.
947  *	@skb: current event.
948  *
949  *	This action sends an RR response with f-bit set to ack_pf flag as
950  *	acknowledge to all received PDUs which have not been acknowledged, yet,
951  *	if there is any. ack_pf flag indicates if a PDU has been received with
952  *	p-bit set to one. Returns 0 for success, 1 otherwise.
953  */
954 static int llc_conn_ac_send_rr_rsp_f_set_ackpf(struct sock *sk,
955 					       struct sk_buff *skb)
956 {
957 	int rc = -ENOBUFS;
958 	struct llc_sock *llc = llc_sk(sk);
959 	struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
960 
961 	if (nskb) {
962 		struct llc_sap *sap = llc->sap;
963 
964 		llc_pdu_header_init(nskb, LLC_PDU_TYPE_S, sap->laddr.lsap,
965 				    llc->daddr.lsap, LLC_PDU_RSP);
966 		llc_pdu_init_as_rr_rsp(nskb, llc->ack_pf, llc->vR);
967 		rc = llc_mac_hdr_init(nskb, llc->dev->dev_addr, llc->daddr.mac);
968 		if (unlikely(rc))
969 			goto free;
970 		llc_conn_send_pdu(sk, nskb);
971 	}
972 out:
973 	return rc;
974 free:
975 	kfree_skb(nskb);
976 	goto out;
977 }
978 
979 /**
980  *	llc_conn_ac_inc_npta_value - tries to make value of npta greater
981  *	@sk: current connection structure.
982  *	@skb: current event.
983  *
984  *	After "inc_cntr" times calling of this action, "npta" increase by one.
985  *	this action tries to make vale of "npta" greater as possible; number of
986  *	acknowledgements decreases by increasing of "npta". Returns 0 for
987  *	success, 1 otherwise.
988  */
989 static int llc_conn_ac_inc_npta_value(struct sock *sk, struct sk_buff *skb)
990 {
991 	struct llc_sock *llc = llc_sk(sk);
992 
993 	if (!llc->inc_cntr) {
994 		llc->dec_step = 0;
995 		llc->dec_cntr = llc->inc_cntr = 2;
996 		++llc->npta;
997 		if (llc->npta > 127)
998 			llc->npta = 127 ;
999 	} else
1000 		--llc->inc_cntr;
1001 	return 0;
1002 }
1003 
1004 /**
1005  *	llc_conn_ac_adjust_npta_by_rr - decreases "npta" by one
1006  *	@sk: current connection structure.
1007  *	@skb: current event.
1008  *
1009  *	After receiving "dec_cntr" times RR command, this action decreases
1010  *	"npta" by one. Returns 0 for success, 1 otherwise.
1011  */
1012 int llc_conn_ac_adjust_npta_by_rr(struct sock *sk, struct sk_buff *skb)
1013 {
1014 	struct llc_sock *llc = llc_sk(sk);
1015 
1016 	if (!llc->connect_step && !llc->remote_busy_flag) {
1017 		if (!llc->dec_step) {
1018 			if (!llc->dec_cntr) {
1019 				llc->inc_cntr = llc->dec_cntr = 2;
1020 				if (llc->npta > 0)
1021 					llc->npta = llc->npta - 1;
1022 			} else
1023 				llc->dec_cntr -=1;
1024 		}
1025 	} else
1026 		llc->connect_step = 0 ;
1027 	return 0;
1028 }
1029 
1030 /**
1031  *	llc_conn_ac_adjust_npta_by_rnr - decreases "npta" by one
1032  *	@sk: current connection structure.
1033  *	@skb: current event.
1034  *
1035  *	After receiving "dec_cntr" times RNR command, this action decreases
1036  *	"npta" by one. Returns 0 for success, 1 otherwise.
1037  */
1038 int llc_conn_ac_adjust_npta_by_rnr(struct sock *sk, struct sk_buff *skb)
1039 {
1040 	struct llc_sock *llc = llc_sk(sk);
1041 
1042 	if (llc->remote_busy_flag)
1043 		if (!llc->dec_step) {
1044 			if (!llc->dec_cntr) {
1045 				llc->inc_cntr = llc->dec_cntr = 2;
1046 				if (llc->npta > 0)
1047 					--llc->npta;
1048 			} else
1049 				--llc->dec_cntr;
1050 		}
1051 	return 0;
1052 }
1053 
1054 /**
1055  *	llc_conn_ac_dec_tx_win_size - decreases tx window size
1056  *	@sk: current connection structure.
1057  *	@skb: current event.
1058  *
1059  *	After receiving of a REJ command or response, transmit window size is
1060  *	decreased by number of PDUs which are outstanding yet. Returns 0 for
1061  *	success, 1 otherwise.
1062  */
1063 int llc_conn_ac_dec_tx_win_size(struct sock *sk, struct sk_buff *skb)
1064 {
1065 	struct llc_sock *llc = llc_sk(sk);
1066 	u8 unacked_pdu = skb_queue_len(&llc->pdu_unack_q);
1067 
1068 	llc->k -= unacked_pdu;
1069 	if (llc->k < 2)
1070 		llc->k = 2;
1071 	return 0;
1072 }
1073 
1074 /**
1075  *	llc_conn_ac_inc_tx_win_size - tx window size is inc by 1
1076  *	@sk: current connection structure.
1077  *	@skb: current event.
1078  *
1079  *	After receiving an RR response with f-bit set to one, transmit window
1080  *	size is increased by one. Returns 0 for success, 1 otherwise.
1081  */
1082 int llc_conn_ac_inc_tx_win_size(struct sock *sk, struct sk_buff *skb)
1083 {
1084 	struct llc_sock *llc = llc_sk(sk);
1085 
1086 	llc->k += 1;
1087 	if (llc->k > 128)
1088 		llc->k = 128 ;
1089 	return 0;
1090 }
1091 
1092 int llc_conn_ac_stop_all_timers(struct sock *sk, struct sk_buff *skb)
1093 {
1094 	struct llc_sock *llc = llc_sk(sk);
1095 
1096 	del_timer(&llc->pf_cycle_timer.timer);
1097 	del_timer(&llc->ack_timer.timer);
1098 	del_timer(&llc->rej_sent_timer.timer);
1099 	del_timer(&llc->busy_state_timer.timer);
1100 	llc->ack_must_be_send = 0;
1101 	llc->ack_pf = 0;
1102 	return 0;
1103 }
1104 
1105 int llc_conn_ac_stop_other_timers(struct sock *sk, struct sk_buff *skb)
1106 {
1107 	struct llc_sock *llc = llc_sk(sk);
1108 
1109 	del_timer(&llc->rej_sent_timer.timer);
1110 	del_timer(&llc->pf_cycle_timer.timer);
1111 	del_timer(&llc->busy_state_timer.timer);
1112 	llc->ack_must_be_send = 0;
1113 	llc->ack_pf = 0;
1114 	return 0;
1115 }
1116 
1117 int llc_conn_ac_start_ack_timer(struct sock *sk, struct sk_buff *skb)
1118 {
1119 	struct llc_sock *llc = llc_sk(sk);
1120 
1121 	mod_timer(&llc->ack_timer.timer, jiffies + llc->ack_timer.expire);
1122 	return 0;
1123 }
1124 
1125 int llc_conn_ac_start_rej_timer(struct sock *sk, struct sk_buff *skb)
1126 {
1127 	struct llc_sock *llc = llc_sk(sk);
1128 
1129 	mod_timer(&llc->rej_sent_timer.timer,
1130 		  jiffies + llc->rej_sent_timer.expire);
1131 	return 0;
1132 }
1133 
1134 int llc_conn_ac_start_ack_tmr_if_not_running(struct sock *sk,
1135 					     struct sk_buff *skb)
1136 {
1137 	struct llc_sock *llc = llc_sk(sk);
1138 
1139 	if (!timer_pending(&llc->ack_timer.timer))
1140 		mod_timer(&llc->ack_timer.timer,
1141 			  jiffies + llc->ack_timer.expire);
1142 	return 0;
1143 }
1144 
1145 int llc_conn_ac_stop_ack_timer(struct sock *sk, struct sk_buff *skb)
1146 {
1147 	del_timer(&llc_sk(sk)->ack_timer.timer);
1148 	return 0;
1149 }
1150 
1151 int llc_conn_ac_stop_p_timer(struct sock *sk, struct sk_buff *skb)
1152 {
1153 	struct llc_sock *llc = llc_sk(sk);
1154 
1155 	del_timer(&llc->pf_cycle_timer.timer);
1156 	llc_conn_set_p_flag(sk, 0);
1157 	return 0;
1158 }
1159 
1160 int llc_conn_ac_stop_rej_timer(struct sock *sk, struct sk_buff *skb)
1161 {
1162 	del_timer(&llc_sk(sk)->rej_sent_timer.timer);
1163 	return 0;
1164 }
1165 
1166 int llc_conn_ac_upd_nr_received(struct sock *sk, struct sk_buff *skb)
1167 {
1168 	int acked;
1169 	u16 unacked = 0;
1170 	struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
1171 	struct llc_sock *llc = llc_sk(sk);
1172 
1173 	llc->last_nr = PDU_SUPV_GET_Nr(pdu);
1174 	acked = llc_conn_remove_acked_pdus(sk, llc->last_nr, &unacked);
1175 	/* On loopback we don't queue I frames in unack_pdu_q queue. */
1176 	if (acked > 0 || (llc->dev->flags & IFF_LOOPBACK)) {
1177 		llc->retry_count = 0;
1178 		del_timer(&llc->ack_timer.timer);
1179 		if (llc->failed_data_req) {
1180 			/* already, we did not accept data from upper layer
1181 			 * (tx_window full or unacceptable state). Now, we
1182 			 * can send data and must inform to upper layer.
1183 			 */
1184 			llc->failed_data_req = 0;
1185 			llc_conn_ac_data_confirm(sk, skb);
1186 		}
1187 		if (unacked)
1188 			mod_timer(&llc->ack_timer.timer,
1189 				  jiffies + llc->ack_timer.expire);
1190 	} else if (llc->failed_data_req) {
1191 		u8 f_bit;
1192 
1193 		llc_pdu_decode_pf_bit(skb, &f_bit);
1194 		if (f_bit == 1) {
1195 			llc->failed_data_req = 0;
1196 			llc_conn_ac_data_confirm(sk, skb);
1197 		}
1198 	}
1199 	return 0;
1200 }
1201 
1202 int llc_conn_ac_upd_p_flag(struct sock *sk, struct sk_buff *skb)
1203 {
1204 	struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
1205 
1206 	if (LLC_PDU_IS_RSP(pdu)) {
1207 		u8 f_bit;
1208 
1209 		llc_pdu_decode_pf_bit(skb, &f_bit);
1210 		if (f_bit) {
1211 			llc_conn_set_p_flag(sk, 0);
1212 			llc_conn_ac_stop_p_timer(sk, skb);
1213 		}
1214 	}
1215 	return 0;
1216 }
1217 
1218 int llc_conn_ac_set_data_flag_2(struct sock *sk, struct sk_buff *skb)
1219 {
1220 	llc_sk(sk)->data_flag = 2;
1221 	return 0;
1222 }
1223 
1224 int llc_conn_ac_set_data_flag_0(struct sock *sk, struct sk_buff *skb)
1225 {
1226 	llc_sk(sk)->data_flag = 0;
1227 	return 0;
1228 }
1229 
1230 int llc_conn_ac_set_data_flag_1(struct sock *sk, struct sk_buff *skb)
1231 {
1232 	llc_sk(sk)->data_flag = 1;
1233 	return 0;
1234 }
1235 
1236 int llc_conn_ac_set_data_flag_1_if_data_flag_eq_0(struct sock *sk,
1237 						  struct sk_buff *skb)
1238 {
1239 	if (!llc_sk(sk)->data_flag)
1240 		llc_sk(sk)->data_flag = 1;
1241 	return 0;
1242 }
1243 
1244 int llc_conn_ac_set_p_flag_0(struct sock *sk, struct sk_buff *skb)
1245 {
1246 	llc_conn_set_p_flag(sk, 0);
1247 	return 0;
1248 }
1249 
1250 static int llc_conn_ac_set_p_flag_1(struct sock *sk, struct sk_buff *skb)
1251 {
1252 	llc_conn_set_p_flag(sk, 1);
1253 	return 0;
1254 }
1255 
1256 int llc_conn_ac_set_remote_busy_0(struct sock *sk, struct sk_buff *skb)
1257 {
1258 	llc_sk(sk)->remote_busy_flag = 0;
1259 	return 0;
1260 }
1261 
1262 int llc_conn_ac_set_cause_flag_0(struct sock *sk, struct sk_buff *skb)
1263 {
1264 	llc_sk(sk)->cause_flag = 0;
1265 	return 0;
1266 }
1267 
1268 int llc_conn_ac_set_cause_flag_1(struct sock *sk, struct sk_buff *skb)
1269 {
1270 	llc_sk(sk)->cause_flag = 1;
1271 	return 0;
1272 }
1273 
1274 int llc_conn_ac_set_retry_cnt_0(struct sock *sk, struct sk_buff *skb)
1275 {
1276 	llc_sk(sk)->retry_count = 0;
1277 	return 0;
1278 }
1279 
1280 int llc_conn_ac_inc_retry_cnt_by_1(struct sock *sk, struct sk_buff *skb)
1281 {
1282 	llc_sk(sk)->retry_count++;
1283 	return 0;
1284 }
1285 
1286 int llc_conn_ac_set_vr_0(struct sock *sk, struct sk_buff *skb)
1287 {
1288 	llc_sk(sk)->vR = 0;
1289 	return 0;
1290 }
1291 
1292 int llc_conn_ac_inc_vr_by_1(struct sock *sk, struct sk_buff *skb)
1293 {
1294 	llc_sk(sk)->vR = PDU_GET_NEXT_Vr(llc_sk(sk)->vR);
1295 	return 0;
1296 }
1297 
1298 int llc_conn_ac_set_vs_0(struct sock *sk, struct sk_buff *skb)
1299 {
1300 	llc_sk(sk)->vS = 0;
1301 	return 0;
1302 }
1303 
1304 int llc_conn_ac_set_vs_nr(struct sock *sk, struct sk_buff *skb)
1305 {
1306 	llc_sk(sk)->vS = llc_sk(sk)->last_nr;
1307 	return 0;
1308 }
1309 
1310 static int llc_conn_ac_inc_vs_by_1(struct sock *sk, struct sk_buff *skb)
1311 {
1312 	llc_sk(sk)->vS = (llc_sk(sk)->vS + 1) % 128;
1313 	return 0;
1314 }
1315 
1316 static void llc_conn_tmr_common_cb(unsigned long timeout_data, u8 type)
1317 {
1318 	struct sock *sk = (struct sock *)timeout_data;
1319 	struct sk_buff *skb = alloc_skb(0, GFP_ATOMIC);
1320 
1321 	bh_lock_sock(sk);
1322 	if (skb) {
1323 		struct llc_conn_state_ev *ev = llc_conn_ev(skb);
1324 
1325 		skb_set_owner_r(skb, sk);
1326 		ev->type = type;
1327 		llc_process_tmr_ev(sk, skb);
1328 	}
1329 	bh_unlock_sock(sk);
1330 }
1331 
1332 void llc_conn_pf_cycle_tmr_cb(unsigned long timeout_data)
1333 {
1334 	llc_conn_tmr_common_cb(timeout_data, LLC_CONN_EV_TYPE_P_TMR);
1335 }
1336 
1337 void llc_conn_busy_tmr_cb(unsigned long timeout_data)
1338 {
1339 	llc_conn_tmr_common_cb(timeout_data, LLC_CONN_EV_TYPE_BUSY_TMR);
1340 }
1341 
1342 void llc_conn_ack_tmr_cb(unsigned long timeout_data)
1343 {
1344 	llc_conn_tmr_common_cb(timeout_data, LLC_CONN_EV_TYPE_ACK_TMR);
1345 }
1346 
1347 void llc_conn_rej_tmr_cb(unsigned long timeout_data)
1348 {
1349 	llc_conn_tmr_common_cb(timeout_data, LLC_CONN_EV_TYPE_REJ_TMR);
1350 }
1351 
1352 int llc_conn_ac_rst_vs(struct sock *sk, struct sk_buff *skb)
1353 {
1354 	llc_sk(sk)->X = llc_sk(sk)->vS;
1355 	llc_conn_ac_set_vs_nr(sk, skb);
1356 	return 0;
1357 }
1358 
1359 int llc_conn_ac_upd_vs(struct sock *sk, struct sk_buff *skb)
1360 {
1361 	struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
1362 	u8 nr = PDU_SUPV_GET_Nr(pdu);
1363 
1364 	if (llc_circular_between(llc_sk(sk)->vS, nr, llc_sk(sk)->X))
1365 		llc_conn_ac_set_vs_nr(sk, skb);
1366 	return 0;
1367 }
1368 
1369 /*
1370  * Non-standard actions; these not contained in IEEE specification; for
1371  * our own usage
1372  */
1373 /**
1374  *	llc_conn_disc - removes connection from SAP list and frees it
1375  *	@sk: closed connection
1376  *	@skb: occurred event
1377  */
1378 int llc_conn_disc(struct sock *sk, struct sk_buff *skb)
1379 {
1380 	/* FIXME: this thing seems to want to die */
1381 	return 0;
1382 }
1383 
1384 /**
1385  *	llc_conn_reset - resets connection
1386  *	@sk : reseting connection.
1387  *	@skb: occurred event.
1388  *
1389  *	Stop all timers, empty all queues and reset all flags.
1390  */
1391 int llc_conn_reset(struct sock *sk, struct sk_buff *skb)
1392 {
1393 	llc_sk_reset(sk);
1394 	return 0;
1395 }
1396 
1397 /**
1398  *	llc_circular_between - designates that b is between a and c or not
1399  *	@a: lower bound
1400  *	@b: element to see if is between a and b
1401  *	@c: upper bound
1402  *
1403  *	This function designates that b is between a and c or not (for example,
1404  *	0 is between 127 and 1). Returns 1 if b is between a and c, 0
1405  *	otherwise.
1406  */
1407 u8 llc_circular_between(u8 a, u8 b, u8 c)
1408 {
1409 	b = b - a;
1410 	c = c - a;
1411 	return b <= c;
1412 }
1413 
1414 /**
1415  *	llc_process_tmr_ev - timer backend
1416  *	@sk: active connection
1417  *	@skb: occurred event
1418  *
1419  *	This function is called from timer callback functions. When connection
1420  *	is busy (during sending a data frame) timer expiration event must be
1421  *	queued. Otherwise this event can be sent to connection state machine.
1422  *	Queued events will process by llc_backlog_rcv function after sending
1423  *	data frame.
1424  */
1425 static void llc_process_tmr_ev(struct sock *sk, struct sk_buff *skb)
1426 {
1427 	if (llc_sk(sk)->state == LLC_CONN_OUT_OF_SVC) {
1428 		printk(KERN_WARNING "%s: timer called on closed connection\n",
1429 		       __FUNCTION__);
1430 		kfree_skb(skb);
1431 	} else {
1432 		if (!sock_owned_by_user(sk))
1433 			llc_conn_state_process(sk, skb);
1434 		else {
1435 			llc_set_backlog_type(skb, LLC_EVENT);
1436 			sk_add_backlog(sk, skb);
1437 		}
1438 	}
1439 }
1440