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Merge branch 'devel' of master.kernel.org:/home/rmk/linux-2.6-serial
[linux.git] / net / llc / llc_station.c
CommitLineData
1da177e4
LT		 1/*
2 * llc_station.c - station component of LLC
3 *
4 * Copyright (c) 1997 by Procom Technology, Inc.
5 * 2001-2003 by Arnaldo Carvalho de Melo <[email protected]>
6 *
7 * This program can be redistributed or modified under the terms of the
8 * GNU General Public License as published by the Free Software Foundation.
9 * This program is distributed without any warranty or implied warranty
10 * of merchantability or fitness for a particular purpose.
11 *
12 * See the GNU General Public License for more details.
13 */
1da177e4
LT		 14#include <linux/init.h>
15#include <linux/module.h>
16#include <net/llc.h>
17#include <net/llc_sap.h>
18#include <net/llc_conn.h>
19#include <net/llc_c_ac.h>
20#include <net/llc_s_ac.h>
21#include <net/llc_c_ev.h>
22#include <net/llc_c_st.h>
23#include <net/llc_s_ev.h>
24#include <net/llc_s_st.h>
25#include <net/llc_pdu.h>
26
27/**
28 * struct llc_station - LLC station component
29 *
30 * SAP and connection resource manager, one per adapter.
31 *
32 * @state - state of station
33 * @xid_r_count - XID response PDU counter
34 * @mac_sa - MAC source address
35 * @sap_list - list of related SAPs
36 * @ev_q - events entering state mach.
37 * @mac_pdu_q - PDUs ready to send to MAC
38 */
39struct llc_station {
40 u8 state;
41 u8 xid_r_count;
42 struct timer_list ack_timer;
43 u8 retry_count;
44 u8 maximum_retry;
45 struct {
46 struct sk_buff_head list;
47 spinlock_t lock;
48 } ev_q;
49 struct sk_buff_head mac_pdu_q;
50};
51
590232a7
ACM		 52#define LLC_STATION_ACK_TIME (3 * HZ)
53
54int sysctl_llc_station_ack_timeout = LLC_STATION_ACK_TIME;
55
1da177e4
LT		 56/* Types of events (possible values in 'ev->type') */
57#define LLC_STATION_EV_TYPE_SIMPLE 1
58#define LLC_STATION_EV_TYPE_CONDITION 2
59#define LLC_STATION_EV_TYPE_PRIM 3
60#define LLC_STATION_EV_TYPE_PDU 4 /* command/response PDU */
61#define LLC_STATION_EV_TYPE_ACK_TMR 5
62#define LLC_STATION_EV_TYPE_RPT_STATUS 6
63
64/* Events */
65#define LLC_STATION_EV_ENABLE_WITH_DUP_ADDR_CHECK 1
66#define LLC_STATION_EV_ENABLE_WITHOUT_DUP_ADDR_CHECK 2
67#define LLC_STATION_EV_ACK_TMR_EXP_LT_RETRY_CNT_MAX_RETRY 3
68#define LLC_STATION_EV_ACK_TMR_EXP_EQ_RETRY_CNT_MAX_RETRY 4
69#define LLC_STATION_EV_RX_NULL_DSAP_XID_C 5
70#define LLC_STATION_EV_RX_NULL_DSAP_0_XID_R_XID_R_CNT_EQ 6
71#define LLC_STATION_EV_RX_NULL_DSAP_1_XID_R_XID_R_CNT_EQ 7
72#define LLC_STATION_EV_RX_NULL_DSAP_TEST_C 8
73#define LLC_STATION_EV_DISABLE_REQ 9
74
75struct llc_station_state_ev {
76 u8 type;
77 u8 prim;
78 u8 prim_type;
79 u8 reason;
80 struct list_head node; /* node in station->ev_q.list */
81};
82
83static __inline__ struct llc_station_state_ev *
84 llc_station_ev(struct sk_buff *skb)
85{
86 return (struct llc_station_state_ev *)skb->cb;
87}
88
89typedef int (*llc_station_ev_t)(struct sk_buff *skb);
90
91#define LLC_STATION_STATE_DOWN 1 /* initial state */
92#define LLC_STATION_STATE_DUP_ADDR_CHK 2
93#define LLC_STATION_STATE_UP 3
94
95#define LLC_NBR_STATION_STATES 3 /* size of state table */
96
97typedef int (*llc_station_action_t)(struct sk_buff *skb);
98
99/* Station component state table structure */
100struct llc_station_state_trans {
101 llc_station_ev_t ev;
102 u8 next_state;
103 llc_station_action_t *ev_actions;
104};
105
106struct llc_station_state {
107 u8 curr_state;
108 struct llc_station_state_trans **transitions;
109};
110
111static struct llc_station llc_main_station;
112
113static int llc_stat_ev_enable_with_dup_addr_check(struct sk_buff *skb)
114{
115 struct llc_station_state_ev *ev = llc_station_ev(skb);
116
117 return ev->type == LLC_STATION_EV_TYPE_SIMPLE &&
118 ev->prim_type ==
119 LLC_STATION_EV_ENABLE_WITH_DUP_ADDR_CHECK ? 0 : 1;
120}
121
122static int llc_stat_ev_enable_without_dup_addr_check(struct sk_buff *skb)
123{
124 struct llc_station_state_ev *ev = llc_station_ev(skb);
125
126 return ev->type == LLC_STATION_EV_TYPE_SIMPLE &&
127 ev->prim_type ==
128 LLC_STATION_EV_ENABLE_WITHOUT_DUP_ADDR_CHECK ? 0 : 1;
129}
130
131static int llc_stat_ev_ack_tmr_exp_lt_retry_cnt_max_retry(struct sk_buff *skb)
132{
133 struct llc_station_state_ev *ev = llc_station_ev(skb);
134
135 return ev->type == LLC_STATION_EV_TYPE_ACK_TMR &&
136 llc_main_station.retry_count <
137 llc_main_station.maximum_retry ? 0 : 1;
138}
139
140static int llc_stat_ev_ack_tmr_exp_eq_retry_cnt_max_retry(struct sk_buff *skb)
141{
142 struct llc_station_state_ev *ev = llc_station_ev(skb);
143
144 return ev->type == LLC_STATION_EV_TYPE_ACK_TMR &&
145 llc_main_station.retry_count ==
146 llc_main_station.maximum_retry ? 0 : 1;
147}
148
149static int llc_stat_ev_rx_null_dsap_xid_c(struct sk_buff *skb)
150{
151 struct llc_station_state_ev *ev = llc_station_ev(skb);
152 struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
153
154 return ev->type == LLC_STATION_EV_TYPE_PDU &&
155 LLC_PDU_IS_CMD(pdu) && /* command PDU */
156 LLC_PDU_TYPE_IS_U(pdu) && /* U type PDU */
157 LLC_U_PDU_CMD(pdu) == LLC_1_PDU_CMD_XID &&
158 !pdu->dsap ? 0 : 1; /* NULL DSAP value */
159}
160
161static int llc_stat_ev_rx_null_dsap_0_xid_r_xid_r_cnt_eq(struct sk_buff *skb)
162{
163 struct llc_station_state_ev *ev = llc_station_ev(skb);
164 struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
165
166 return ev->type == LLC_STATION_EV_TYPE_PDU &&
167 LLC_PDU_IS_RSP(pdu) && /* response PDU */
168 LLC_PDU_TYPE_IS_U(pdu) && /* U type PDU */
169 LLC_U_PDU_RSP(pdu) == LLC_1_PDU_CMD_XID &&
170 !pdu->dsap && /* NULL DSAP value */
171 !llc_main_station.xid_r_count ? 0 : 1;
172}
173
174static int llc_stat_ev_rx_null_dsap_1_xid_r_xid_r_cnt_eq(struct sk_buff *skb)
175{
176 struct llc_station_state_ev *ev = llc_station_ev(skb);
177 struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
178
179 return ev->type == LLC_STATION_EV_TYPE_PDU &&
180 LLC_PDU_IS_RSP(pdu) && /* response PDU */
181 LLC_PDU_TYPE_IS_U(pdu) && /* U type PDU */
182 LLC_U_PDU_RSP(pdu) == LLC_1_PDU_CMD_XID &&
183 !pdu->dsap && /* NULL DSAP value */
184 llc_main_station.xid_r_count == 1 ? 0 : 1;
185}
186
187static int llc_stat_ev_rx_null_dsap_test_c(struct sk_buff *skb)
188{
189 struct llc_station_state_ev *ev = llc_station_ev(skb);
190 struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
191
192 return ev->type == LLC_STATION_EV_TYPE_PDU &&
193 LLC_PDU_IS_CMD(pdu) && /* command PDU */
194 LLC_PDU_TYPE_IS_U(pdu) && /* U type PDU */
195 LLC_U_PDU_CMD(pdu) == LLC_1_PDU_CMD_TEST &&
196 !pdu->dsap ? 0 : 1; /* NULL DSAP */
197}
198
199static int llc_stat_ev_disable_req(struct sk_buff *skb)
200{
201 struct llc_station_state_ev *ev = llc_station_ev(skb);
202
203 return ev->type == LLC_STATION_EV_TYPE_PRIM &&
204 ev->prim == LLC_DISABLE_PRIM &&
205 ev->prim_type == LLC_PRIM_TYPE_REQ ? 0 : 1;
206}
207
208/**
209 * llc_station_send_pdu - queues PDU to send
210 * @skb: Address of the PDU
211 *
212 * Queues a PDU to send to the MAC layer.
213 */
214static void llc_station_send_pdu(struct sk_buff *skb)
215{
216 skb_queue_tail(&llc_main_station.mac_pdu_q, skb);
217 while ((skb = skb_dequeue(&llc_main_station.mac_pdu_q)) != NULL)
218 if (dev_queue_xmit(skb))
219 break;
220}
221
222static int llc_station_ac_start_ack_timer(struct sk_buff *skb)
223{
590232a7
ACM		 224 mod_timer(&llc_main_station.ack_timer,
225 jiffies + sysctl_llc_station_ack_timeout);
1da177e4
LT		 226 return 0;
227}
228
229static int llc_station_ac_set_retry_cnt_0(struct sk_buff *skb)
230{
231 llc_main_station.retry_count = 0;
232 return 0;
233}
234
235static int llc_station_ac_inc_retry_cnt_by_1(struct sk_buff *skb)
236{
237 llc_main_station.retry_count++;
238 return 0;
239}
240
241static int llc_station_ac_set_xid_r_cnt_0(struct sk_buff *skb)
242{
243 llc_main_station.xid_r_count = 0;
244 return 0;
245}
246
247static int llc_station_ac_inc_xid_r_cnt_by_1(struct sk_buff *skb)
248{
249 llc_main_station.xid_r_count++;
250 return 0;
251}
252
253static int llc_station_ac_send_null_dsap_xid_c(struct sk_buff *skb)
254{
255 int rc = 1;
d389424e 256 struct sk_buff *nskb = llc_alloc_frame(NULL, skb->dev);
1da177e4
LT		 257
258 if (!nskb)
259 goto out;
260 llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, 0, 0, LLC_PDU_CMD);
261 llc_pdu_init_as_xid_cmd(nskb, LLC_XID_NULL_CLASS_2, 127);
262 rc = llc_mac_hdr_init(nskb, llc_station_mac_sa, llc_station_mac_sa);
249ff1c6 263 if (unlikely(rc))
1da177e4
LT		 264 goto free;
265 llc_station_send_pdu(nskb);
266out:
267 return rc;
268free:
269 kfree_skb(skb);
270 goto out;
271}
272
273static int llc_station_ac_send_xid_r(struct sk_buff *skb)
274{
275 u8 mac_da[ETH_ALEN], dsap;
276 int rc = 1;
d389424e 277 struct sk_buff* nskb = llc_alloc_frame(NULL, skb->dev);
1da177e4
LT		 278
279 if (!nskb)
280 goto out;
281 rc = 0;
1da177e4
LT		 282 llc_pdu_decode_sa(skb, mac_da);
283 llc_pdu_decode_ssap(skb, &dsap);
284 llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, 0, dsap, LLC_PDU_RSP);
285 llc_pdu_init_as_xid_rsp(nskb, LLC_XID_NULL_CLASS_2, 127);
286 rc = llc_mac_hdr_init(nskb, llc_station_mac_sa, mac_da);
249ff1c6 287 if (unlikely(rc))
1da177e4
LT		 288 goto free;
289 llc_station_send_pdu(nskb);
290out:
291 return rc;
292free:
293 kfree_skb(skb);
294 goto out;
295}
296
297static int llc_station_ac_send_test_r(struct sk_buff *skb)
298{
299 u8 mac_da[ETH_ALEN], dsap;
300 int rc = 1;
d389424e 301 struct sk_buff *nskb = llc_alloc_frame(NULL, skb->dev);
1da177e4
LT		 302
303 if (!nskb)
304 goto out;
305 rc = 0;
1da177e4
LT		 306 llc_pdu_decode_sa(skb, mac_da);
307 llc_pdu_decode_ssap(skb, &dsap);
308 llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, 0, dsap, LLC_PDU_RSP);
309 llc_pdu_init_as_test_rsp(nskb, skb);
310 rc = llc_mac_hdr_init(nskb, llc_station_mac_sa, mac_da);
249ff1c6 311 if (unlikely(rc))
1da177e4
LT		 312 goto free;
313 llc_station_send_pdu(nskb);
314out:
315 return rc;
316free:
317 kfree_skb(skb);
318 goto out;
319}
320
321static int llc_station_ac_report_status(struct sk_buff *skb)
322{
323 return 0;
324}
325
326/* COMMON STATION STATE transitions */
327
328/* dummy last-transition indicator; common to all state transition groups
329 * last entry for this state
330 * all members are zeros, .bss zeroes it
331 */
332static struct llc_station_state_trans llc_stat_state_trans_end;
333
334/* DOWN STATE transitions */
335
336/* state transition for LLC_STATION_EV_ENABLE_WITH_DUP_ADDR_CHECK event */
337static llc_station_action_t llc_stat_down_state_actions_1[] = {
338 [0] = llc_station_ac_start_ack_timer,
339 [1] = llc_station_ac_set_retry_cnt_0,
340 [2] = llc_station_ac_set_xid_r_cnt_0,
341 [3] = llc_station_ac_send_null_dsap_xid_c,
342 [4] = NULL,
343};
344
345static struct llc_station_state_trans llc_stat_down_state_trans_1 = {
346 .ev = llc_stat_ev_enable_with_dup_addr_check,
347 .next_state = LLC_STATION_STATE_DUP_ADDR_CHK,
348 .ev_actions = llc_stat_down_state_actions_1,
349};
350
351/* state transition for LLC_STATION_EV_ENABLE_WITHOUT_DUP_ADDR_CHECK event */
352static llc_station_action_t llc_stat_down_state_actions_2[] = {
353 [0] = llc_station_ac_report_status, /* STATION UP */
354 [1] = NULL,
355};
356
357static struct llc_station_state_trans llc_stat_down_state_trans_2 = {
358 .ev = llc_stat_ev_enable_without_dup_addr_check,
359 .next_state = LLC_STATION_STATE_UP,
360 .ev_actions = llc_stat_down_state_actions_2,
361};
362
363/* array of pointers; one to each transition */
364static struct llc_station_state_trans *llc_stat_dwn_state_trans[] = {
365 [0] = &llc_stat_down_state_trans_1,
366 [1] = &llc_stat_down_state_trans_2,
367 [2] = &llc_stat_state_trans_end,
368};
369
370/* UP STATE transitions */
371/* state transition for LLC_STATION_EV_DISABLE_REQ event */
372static llc_station_action_t llc_stat_up_state_actions_1[] = {
373 [0] = llc_station_ac_report_status, /* STATION DOWN */
374 [1] = NULL,
375};
376
377static struct llc_station_state_trans llc_stat_up_state_trans_1 = {
378 .ev = llc_stat_ev_disable_req,
379 .next_state = LLC_STATION_STATE_DOWN,
380 .ev_actions = llc_stat_up_state_actions_1,
381};
382
383/* state transition for LLC_STATION_EV_RX_NULL_DSAP_XID_C event */
384static llc_station_action_t llc_stat_up_state_actions_2[] = {
385 [0] = llc_station_ac_send_xid_r,
386 [1] = NULL,
387};
388
389static struct llc_station_state_trans llc_stat_up_state_trans_2 = {
390 .ev = llc_stat_ev_rx_null_dsap_xid_c,
391 .next_state = LLC_STATION_STATE_UP,
392 .ev_actions = llc_stat_up_state_actions_2,
393};
394
395/* state transition for LLC_STATION_EV_RX_NULL_DSAP_TEST_C event */
396static llc_station_action_t llc_stat_up_state_actions_3[] = {
397 [0] = llc_station_ac_send_test_r,
398 [1] = NULL,
399};
400
401static struct llc_station_state_trans llc_stat_up_state_trans_3 = {
402 .ev = llc_stat_ev_rx_null_dsap_test_c,
403 .next_state = LLC_STATION_STATE_UP,
404 .ev_actions = llc_stat_up_state_actions_3,
405};
406
407/* array of pointers; one to each transition */
408static struct llc_station_state_trans *llc_stat_up_state_trans [] = {
409 [0] = &llc_stat_up_state_trans_1,
410 [1] = &llc_stat_up_state_trans_2,
411 [2] = &llc_stat_up_state_trans_3,
412 [3] = &llc_stat_state_trans_end,
413};
414
415/* DUP ADDR CHK STATE transitions */
416/* state transition for LLC_STATION_EV_RX_NULL_DSAP_0_XID_R_XID_R_CNT_EQ
417 * event
418 */
419static llc_station_action_t llc_stat_dupaddr_state_actions_1[] = {
420 [0] = llc_station_ac_inc_xid_r_cnt_by_1,
421 [1] = NULL,
422};
423
424static struct llc_station_state_trans llc_stat_dupaddr_state_trans_1 = {
425 .ev = llc_stat_ev_rx_null_dsap_0_xid_r_xid_r_cnt_eq,
426 .next_state = LLC_STATION_STATE_DUP_ADDR_CHK,
427 .ev_actions = llc_stat_dupaddr_state_actions_1,
428};
429
430/* state transition for LLC_STATION_EV_RX_NULL_DSAP_1_XID_R_XID_R_CNT_EQ
431 * event
432 */
433static llc_station_action_t llc_stat_dupaddr_state_actions_2[] = {
434 [0] = llc_station_ac_report_status, /* DUPLICATE ADDRESS FOUND */
435 [1] = NULL,
436};
437
438static struct llc_station_state_trans llc_stat_dupaddr_state_trans_2 = {
439 .ev = llc_stat_ev_rx_null_dsap_1_xid_r_xid_r_cnt_eq,
440 .next_state = LLC_STATION_STATE_DOWN,
441 .ev_actions = llc_stat_dupaddr_state_actions_2,
442};
443
444/* state transition for LLC_STATION_EV_RX_NULL_DSAP_XID_C event */
445static llc_station_action_t llc_stat_dupaddr_state_actions_3[] = {
446 [0] = llc_station_ac_send_xid_r,
447 [1] = NULL,
448};
449
450static struct llc_station_state_trans llc_stat_dupaddr_state_trans_3 = {
451 .ev = llc_stat_ev_rx_null_dsap_xid_c,
452 .next_state = LLC_STATION_STATE_DUP_ADDR_CHK,
453 .ev_actions = llc_stat_dupaddr_state_actions_3,
454};
455
456/* state transition for LLC_STATION_EV_ACK_TMR_EXP_LT_RETRY_CNT_MAX_RETRY
457 * event
458 */
459static llc_station_action_t llc_stat_dupaddr_state_actions_4[] = {
460 [0] = llc_station_ac_start_ack_timer,
461 [1] = llc_station_ac_inc_retry_cnt_by_1,
462 [2] = llc_station_ac_set_xid_r_cnt_0,
463 [3] = llc_station_ac_send_null_dsap_xid_c,
464 [4] = NULL,
465};
466
467static struct llc_station_state_trans llc_stat_dupaddr_state_trans_4 = {
468 .ev = llc_stat_ev_ack_tmr_exp_lt_retry_cnt_max_retry,
469 .next_state = LLC_STATION_STATE_DUP_ADDR_CHK,
470 .ev_actions = llc_stat_dupaddr_state_actions_4,
471};
472
473/* state transition for LLC_STATION_EV_ACK_TMR_EXP_EQ_RETRY_CNT_MAX_RETRY
474 * event
475 */
476static llc_station_action_t llc_stat_dupaddr_state_actions_5[] = {
477 [0] = llc_station_ac_report_status, /* STATION UP */
478 [1] = NULL,
479};
480
481static struct llc_station_state_trans llc_stat_dupaddr_state_trans_5 = {
482 .ev = llc_stat_ev_ack_tmr_exp_eq_retry_cnt_max_retry,
483 .next_state = LLC_STATION_STATE_UP,
484 .ev_actions = llc_stat_dupaddr_state_actions_5,
485};
486
487/* state transition for LLC_STATION_EV_DISABLE_REQ event */
488static llc_station_action_t llc_stat_dupaddr_state_actions_6[] = {
489 [0] = llc_station_ac_report_status, /* STATION DOWN */
490 [1] = NULL,
491};
492
493static struct llc_station_state_trans llc_stat_dupaddr_state_trans_6 = {
494 .ev = llc_stat_ev_disable_req,
495 .next_state = LLC_STATION_STATE_DOWN,
496 .ev_actions = llc_stat_dupaddr_state_actions_6,
497};
498
499/* array of pointers; one to each transition */
500static struct llc_station_state_trans *llc_stat_dupaddr_state_trans[] = {
501 [0] = &llc_stat_dupaddr_state_trans_6, /* Request */
502 [1] = &llc_stat_dupaddr_state_trans_4, /* Timer */
503 [2] = &llc_stat_dupaddr_state_trans_5,
504 [3] = &llc_stat_dupaddr_state_trans_1, /* Receive frame */
505 [4] = &llc_stat_dupaddr_state_trans_2,
506 [5] = &llc_stat_dupaddr_state_trans_3,
507 [6] = &llc_stat_state_trans_end,
508};
509
510static struct llc_station_state
511 llc_station_state_table[LLC_NBR_STATION_STATES] = {
512 [LLC_STATION_STATE_DOWN - 1] = {
513 .curr_state = LLC_STATION_STATE_DOWN,
514 .transitions = llc_stat_dwn_state_trans,
515 },
516 [LLC_STATION_STATE_DUP_ADDR_CHK - 1] = {
517 .curr_state = LLC_STATION_STATE_DUP_ADDR_CHK,
518 .transitions = llc_stat_dupaddr_state_trans,
519 },
520 [LLC_STATION_STATE_UP - 1] = {
521 .curr_state = LLC_STATION_STATE_UP,
522 .transitions = llc_stat_up_state_trans,
523 },
524};
525
526/**
527 * llc_exec_station_trans_actions - executes actions for transition
528 * @trans: Address of the transition
529 * @skb: Address of the event that caused the transition
530 *
531 * Executes actions of a transition of the station state machine. Returns
532 * 0 if all actions complete successfully, nonzero otherwise.
533 */
534static u16 llc_exec_station_trans_actions(struct llc_station_state_trans *trans,
535 struct sk_buff *skb)
536{
537 u16 rc = 0;
538 llc_station_action_t *next_action = trans->ev_actions;
539
540 for (; next_action && *next_action; next_action++)
541 if ((*next_action)(skb))
542 rc = 1;
543 return rc;
544}
545
546/**
547 * llc_find_station_trans - finds transition for this event
548 * @skb: Address of the event
549 *
550 * Search thru events of the current state of the station until list
551 * exhausted or it's obvious that the event is not valid for the current
552 * state. Returns the address of the transition if cound, %NULL otherwise.
553 */
554static struct llc_station_state_trans *
555 llc_find_station_trans(struct sk_buff *skb)
556{
557 int i = 0;
558 struct llc_station_state_trans *rc = NULL;
559 struct llc_station_state_trans **next_trans;
560 struct llc_station_state *curr_state =
561 &llc_station_state_table[llc_main_station.state - 1];
562
563 for (next_trans = curr_state->transitions; next_trans[i]->ev; i++)
564 if (!next_trans[i]->ev(skb)) {
565 rc = next_trans[i];
566 break;
567 }
568 return rc;
569}
570
571/**
572 * llc_station_free_ev - frees an event
573 * @skb: Address of the event
574 *
575 * Frees an event.
576 */
577static void llc_station_free_ev(struct sk_buff *skb)
578{
579 struct llc_station_state_ev *ev = llc_station_ev(skb);
580
581 if (ev->type == LLC_STATION_EV_TYPE_PDU)
582 kfree_skb(skb);
583}
584
585/**
586 * llc_station_next_state - processes event and goes to the next state
587 * @skb: Address of the event
588 *
589 * Processes an event, executes any transitions related to that event and
590 * updates the state of the station.
591 */
592static u16 llc_station_next_state(struct sk_buff *skb)
593{
594 u16 rc = 1;
595 struct llc_station_state_trans *trans;
596
597 if (llc_main_station.state > LLC_NBR_STATION_STATES)
598 goto out;
599 trans = llc_find_station_trans(skb);
600 if (trans) {
601 /* got the state to which we next transition; perform the
602 * actions associated with this transition before actually
603 * transitioning to the next state
604 */
605 rc = llc_exec_station_trans_actions(trans, skb);
606 if (!rc)
607 /* transition station to next state if all actions
608 * execute successfully; done; wait for next event
609 */
610 llc_main_station.state = trans->next_state;
611 } else
612 /* event not recognized in current state; re-queue it for
613 * processing again at a later time; return failure
614 */
615 rc = 0;
616out:
617 llc_station_free_ev(skb);
618 return rc;
619}
620
621/**
622 * llc_station_service_events - service events in the queue
623 *
624 * Get an event from the station event queue (if any); attempt to service
625 * the event; if event serviced, get the next event (if any) on the event
626 * queue; if event not service, re-queue the event on the event queue and
627 * attempt to service the next event; when serviced all events in queue,
628 * finished; if don't transition to different state, just service all
629 * events once; if transition to new state, service all events again.
630 * Caller must hold llc_main_station.ev_q.lock.
631 */
632static void llc_station_service_events(void)
633{
634 struct sk_buff *skb;
635
636 while ((skb = skb_dequeue(&llc_main_station.ev_q.list)) != NULL)
637 llc_station_next_state(skb);
638}
639
640/**
641 * llc_station_state_process: queue event and try to process queue.
642 * @skb: Address of the event
643 *
644 * Queues an event (on the station event queue) for handling by the
645 * station state machine and attempts to process any queued-up events.
646 */
647static void llc_station_state_process(struct sk_buff *skb)
648{
649 spin_lock_bh(&llc_main_station.ev_q.lock);
650 skb_queue_tail(&llc_main_station.ev_q.list, skb);
651 llc_station_service_events();
652 spin_unlock_bh(&llc_main_station.ev_q.lock);
653}
654
655static void llc_station_ack_tmr_cb(unsigned long timeout_data)
656{
657 struct sk_buff *skb = alloc_skb(0, GFP_ATOMIC);
658
659 if (skb) {
660 struct llc_station_state_ev *ev = llc_station_ev(skb);
661
662 ev->type = LLC_STATION_EV_TYPE_ACK_TMR;
663 llc_station_state_process(skb);
664 }
665}
666
667/*
668 * llc_station_rcv - send received pdu to the station state machine
669 * @skb: received frame.
670 *
671 * Sends data unit to station state machine.
672 */
673static void llc_station_rcv(struct sk_buff *skb)
674{
675 struct llc_station_state_ev *ev = llc_station_ev(skb);
676
677 ev->type = LLC_STATION_EV_TYPE_PDU;
678 ev->reason = 0;
679 llc_station_state_process(skb);
680}
681
682int __init llc_station_init(void)
683{
684 u16 rc = -ENOBUFS;
685 struct sk_buff *skb;
686 struct llc_station_state_ev *ev;
687
688 skb_queue_head_init(&llc_main_station.mac_pdu_q);
689 skb_queue_head_init(&llc_main_station.ev_q.list);
690 spin_lock_init(&llc_main_station.ev_q.lock);
691 init_timer(&llc_main_station.ack_timer);
692 llc_main_station.ack_timer.data = (unsigned long)&llc_main_station;
693 llc_main_station.ack_timer.function = llc_station_ack_tmr_cb;
590232a7
ACM		 694 llc_main_station.ack_timer.expires = jiffies +
695 sysctl_llc_station_ack_timeout;
1da177e4
LT		 696 skb = alloc_skb(0, GFP_ATOMIC);
697 if (!skb)
698 goto out;
699 rc = 0;
700 llc_set_station_handler(llc_station_rcv);
701 ev = llc_station_ev(skb);
702 memset(ev, 0, sizeof(*ev));
1da177e4
LT		 703 llc_main_station.maximum_retry = 1;
704 llc_main_station.state = LLC_STATION_STATE_DOWN;
705 ev->type = LLC_STATION_EV_TYPE_SIMPLE;
706 ev->prim_type = LLC_STATION_EV_ENABLE_WITHOUT_DUP_ADDR_CHECK;
707 rc = llc_station_next_state(skb);
708out:
709 return rc;
710}
711
712void __exit llc_station_exit(void)
713{
714 llc_set_station_handler(NULL);
715}
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