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-rw-r--r--net/llc/llc_station.c713
1 files changed, 713 insertions, 0 deletions
diff --git a/net/llc/llc_station.c b/net/llc/llc_station.c
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index 000000000000..8fe48a24bad5
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+++ b/net/llc/llc_station.c
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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 <acme@conectiva.com.br>
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 */
14#include <linux/config.h>
15#include <linux/init.h>
16#include <linux/module.h>
17#include <net/llc.h>
18#include <net/llc_sap.h>
19#include <net/llc_conn.h>
20#include <net/llc_c_ac.h>
21#include <net/llc_s_ac.h>
22#include <net/llc_c_ev.h>
23#include <net/llc_c_st.h>
24#include <net/llc_s_ev.h>
25#include <net/llc_s_st.h>
26#include <net/llc_pdu.h>
27
28/**
29 * struct llc_station - LLC station component
30 *
31 * SAP and connection resource manager, one per adapter.
32 *
33 * @state - state of station
34 * @xid_r_count - XID response PDU counter
35 * @mac_sa - MAC source address
36 * @sap_list - list of related SAPs
37 * @ev_q - events entering state mach.
38 * @mac_pdu_q - PDUs ready to send to MAC
39 */
40struct llc_station {
41 u8 state;
42 u8 xid_r_count;
43 struct timer_list ack_timer;
44 u8 retry_count;
45 u8 maximum_retry;
46 struct {
47 struct sk_buff_head list;
48 spinlock_t lock;
49 } ev_q;
50 struct sk_buff_head mac_pdu_q;
51};
52
53/* Types of events (possible values in 'ev->type') */
54#define LLC_STATION_EV_TYPE_SIMPLE 1
55#define LLC_STATION_EV_TYPE_CONDITION 2
56#define LLC_STATION_EV_TYPE_PRIM 3
57#define LLC_STATION_EV_TYPE_PDU 4 /* command/response PDU */
58#define LLC_STATION_EV_TYPE_ACK_TMR 5
59#define LLC_STATION_EV_TYPE_RPT_STATUS 6
60
61/* Events */
62#define LLC_STATION_EV_ENABLE_WITH_DUP_ADDR_CHECK 1
63#define LLC_STATION_EV_ENABLE_WITHOUT_DUP_ADDR_CHECK 2
64#define LLC_STATION_EV_ACK_TMR_EXP_LT_RETRY_CNT_MAX_RETRY 3
65#define LLC_STATION_EV_ACK_TMR_EXP_EQ_RETRY_CNT_MAX_RETRY 4
66#define LLC_STATION_EV_RX_NULL_DSAP_XID_C 5
67#define LLC_STATION_EV_RX_NULL_DSAP_0_XID_R_XID_R_CNT_EQ 6
68#define LLC_STATION_EV_RX_NULL_DSAP_1_XID_R_XID_R_CNT_EQ 7
69#define LLC_STATION_EV_RX_NULL_DSAP_TEST_C 8
70#define LLC_STATION_EV_DISABLE_REQ 9
71
72struct llc_station_state_ev {
73 u8 type;
74 u8 prim;
75 u8 prim_type;
76 u8 reason;
77 struct list_head node; /* node in station->ev_q.list */
78};
79
80static __inline__ struct llc_station_state_ev *
81 llc_station_ev(struct sk_buff *skb)
82{
83 return (struct llc_station_state_ev *)skb->cb;
84}
85
86typedef int (*llc_station_ev_t)(struct sk_buff *skb);
87
88#define LLC_STATION_STATE_DOWN 1 /* initial state */
89#define LLC_STATION_STATE_DUP_ADDR_CHK 2
90#define LLC_STATION_STATE_UP 3
91
92#define LLC_NBR_STATION_STATES 3 /* size of state table */
93
94typedef int (*llc_station_action_t)(struct sk_buff *skb);
95
96/* Station component state table structure */
97struct llc_station_state_trans {
98 llc_station_ev_t ev;
99 u8 next_state;
100 llc_station_action_t *ev_actions;
101};
102
103struct llc_station_state {
104 u8 curr_state;
105 struct llc_station_state_trans **transitions;
106};
107
108static struct llc_station llc_main_station;
109
110static int llc_stat_ev_enable_with_dup_addr_check(struct sk_buff *skb)
111{
112 struct llc_station_state_ev *ev = llc_station_ev(skb);
113
114 return ev->type == LLC_STATION_EV_TYPE_SIMPLE &&
115 ev->prim_type ==
116 LLC_STATION_EV_ENABLE_WITH_DUP_ADDR_CHECK ? 0 : 1;
117}
118
119static int llc_stat_ev_enable_without_dup_addr_check(struct sk_buff *skb)
120{
121 struct llc_station_state_ev *ev = llc_station_ev(skb);
122
123 return ev->type == LLC_STATION_EV_TYPE_SIMPLE &&
124 ev->prim_type ==
125 LLC_STATION_EV_ENABLE_WITHOUT_DUP_ADDR_CHECK ? 0 : 1;
126}
127
128static int llc_stat_ev_ack_tmr_exp_lt_retry_cnt_max_retry(struct sk_buff *skb)
129{
130 struct llc_station_state_ev *ev = llc_station_ev(skb);
131
132 return ev->type == LLC_STATION_EV_TYPE_ACK_TMR &&
133 llc_main_station.retry_count <
134 llc_main_station.maximum_retry ? 0 : 1;
135}
136
137static int llc_stat_ev_ack_tmr_exp_eq_retry_cnt_max_retry(struct sk_buff *skb)
138{
139 struct llc_station_state_ev *ev = llc_station_ev(skb);
140
141 return ev->type == LLC_STATION_EV_TYPE_ACK_TMR &&
142 llc_main_station.retry_count ==
143 llc_main_station.maximum_retry ? 0 : 1;
144}
145
146static int llc_stat_ev_rx_null_dsap_xid_c(struct sk_buff *skb)
147{
148 struct llc_station_state_ev *ev = llc_station_ev(skb);
149 struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
150
151 return ev->type == LLC_STATION_EV_TYPE_PDU &&
152 LLC_PDU_IS_CMD(pdu) && /* command PDU */
153 LLC_PDU_TYPE_IS_U(pdu) && /* U type PDU */
154 LLC_U_PDU_CMD(pdu) == LLC_1_PDU_CMD_XID &&
155 !pdu->dsap ? 0 : 1; /* NULL DSAP value */
156}
157
158static int llc_stat_ev_rx_null_dsap_0_xid_r_xid_r_cnt_eq(struct sk_buff *skb)
159{
160 struct llc_station_state_ev *ev = llc_station_ev(skb);
161 struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
162
163 return ev->type == LLC_STATION_EV_TYPE_PDU &&
164 LLC_PDU_IS_RSP(pdu) && /* response PDU */
165 LLC_PDU_TYPE_IS_U(pdu) && /* U type PDU */
166 LLC_U_PDU_RSP(pdu) == LLC_1_PDU_CMD_XID &&
167 !pdu->dsap && /* NULL DSAP value */
168 !llc_main_station.xid_r_count ? 0 : 1;
169}
170
171static int llc_stat_ev_rx_null_dsap_1_xid_r_xid_r_cnt_eq(struct sk_buff *skb)
172{
173 struct llc_station_state_ev *ev = llc_station_ev(skb);
174 struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
175
176 return ev->type == LLC_STATION_EV_TYPE_PDU &&
177 LLC_PDU_IS_RSP(pdu) && /* response PDU */
178 LLC_PDU_TYPE_IS_U(pdu) && /* U type PDU */
179 LLC_U_PDU_RSP(pdu) == LLC_1_PDU_CMD_XID &&
180 !pdu->dsap && /* NULL DSAP value */
181 llc_main_station.xid_r_count == 1 ? 0 : 1;
182}
183
184static int llc_stat_ev_rx_null_dsap_test_c(struct sk_buff *skb)
185{
186 struct llc_station_state_ev *ev = llc_station_ev(skb);
187 struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
188
189 return ev->type == LLC_STATION_EV_TYPE_PDU &&
190 LLC_PDU_IS_CMD(pdu) && /* command PDU */
191 LLC_PDU_TYPE_IS_U(pdu) && /* U type PDU */
192 LLC_U_PDU_CMD(pdu) == LLC_1_PDU_CMD_TEST &&
193 !pdu->dsap ? 0 : 1; /* NULL DSAP */
194}
195
196static int llc_stat_ev_disable_req(struct sk_buff *skb)
197{
198 struct llc_station_state_ev *ev = llc_station_ev(skb);
199
200 return ev->type == LLC_STATION_EV_TYPE_PRIM &&
201 ev->prim == LLC_DISABLE_PRIM &&
202 ev->prim_type == LLC_PRIM_TYPE_REQ ? 0 : 1;
203}
204
205/**
206 * llc_station_send_pdu - queues PDU to send
207 * @skb: Address of the PDU
208 *
209 * Queues a PDU to send to the MAC layer.
210 */
211static void llc_station_send_pdu(struct sk_buff *skb)
212{
213 skb_queue_tail(&llc_main_station.mac_pdu_q, skb);
214 while ((skb = skb_dequeue(&llc_main_station.mac_pdu_q)) != NULL)
215 if (dev_queue_xmit(skb))
216 break;
217}
218
219static int llc_station_ac_start_ack_timer(struct sk_buff *skb)
220{
221 mod_timer(&llc_main_station.ack_timer, jiffies + LLC_ACK_TIME * HZ);
222 return 0;
223}
224
225static int llc_station_ac_set_retry_cnt_0(struct sk_buff *skb)
226{
227 llc_main_station.retry_count = 0;
228 return 0;
229}
230
231static int llc_station_ac_inc_retry_cnt_by_1(struct sk_buff *skb)
232{
233 llc_main_station.retry_count++;
234 return 0;
235}
236
237static int llc_station_ac_set_xid_r_cnt_0(struct sk_buff *skb)
238{
239 llc_main_station.xid_r_count = 0;
240 return 0;
241}
242
243static int llc_station_ac_inc_xid_r_cnt_by_1(struct sk_buff *skb)
244{
245 llc_main_station.xid_r_count++;
246 return 0;
247}
248
249static int llc_station_ac_send_null_dsap_xid_c(struct sk_buff *skb)
250{
251 int rc = 1;
252 struct sk_buff *nskb = llc_alloc_frame();
253
254 if (!nskb)
255 goto out;
256 llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, 0, 0, LLC_PDU_CMD);
257 llc_pdu_init_as_xid_cmd(nskb, LLC_XID_NULL_CLASS_2, 127);
258 rc = llc_mac_hdr_init(nskb, llc_station_mac_sa, llc_station_mac_sa);
259 if (rc)
260 goto free;
261 llc_station_send_pdu(nskb);
262out:
263 return rc;
264free:
265 kfree_skb(skb);
266 goto out;
267}
268
269static int llc_station_ac_send_xid_r(struct sk_buff *skb)
270{
271 u8 mac_da[ETH_ALEN], dsap;
272 int rc = 1;
273 struct sk_buff* nskb = llc_alloc_frame();
274
275 if (!nskb)
276 goto out;
277 rc = 0;
278 nskb->dev = skb->dev;
279 llc_pdu_decode_sa(skb, mac_da);
280 llc_pdu_decode_ssap(skb, &dsap);
281 llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, 0, dsap, LLC_PDU_RSP);
282 llc_pdu_init_as_xid_rsp(nskb, LLC_XID_NULL_CLASS_2, 127);
283 rc = llc_mac_hdr_init(nskb, llc_station_mac_sa, mac_da);
284 if (rc)
285 goto free;
286 llc_station_send_pdu(nskb);
287out:
288 return rc;
289free:
290 kfree_skb(skb);
291 goto out;
292}
293
294static int llc_station_ac_send_test_r(struct sk_buff *skb)
295{
296 u8 mac_da[ETH_ALEN], dsap;
297 int rc = 1;
298 struct sk_buff *nskb = llc_alloc_frame();
299
300 if (!nskb)
301 goto out;
302 rc = 0;
303 nskb->dev = skb->dev;
304 llc_pdu_decode_sa(skb, mac_da);
305 llc_pdu_decode_ssap(skb, &dsap);
306 llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, 0, dsap, LLC_PDU_RSP);
307 llc_pdu_init_as_test_rsp(nskb, skb);
308 rc = llc_mac_hdr_init(nskb, llc_station_mac_sa, mac_da);
309 if (rc)
310 goto free;
311 llc_station_send_pdu(nskb);
312out:
313 return rc;
314free:
315 kfree_skb(skb);
316 goto out;
317}
318
319static int llc_station_ac_report_status(struct sk_buff *skb)
320{
321 return 0;
322}
323
324/* COMMON STATION STATE transitions */
325
326/* dummy last-transition indicator; common to all state transition groups
327 * last entry for this state
328 * all members are zeros, .bss zeroes it
329 */
330static struct llc_station_state_trans llc_stat_state_trans_end;
331
332/* DOWN STATE transitions */
333
334/* state transition for LLC_STATION_EV_ENABLE_WITH_DUP_ADDR_CHECK event */
335static llc_station_action_t llc_stat_down_state_actions_1[] = {
336 [0] = llc_station_ac_start_ack_timer,
337 [1] = llc_station_ac_set_retry_cnt_0,
338 [2] = llc_station_ac_set_xid_r_cnt_0,
339 [3] = llc_station_ac_send_null_dsap_xid_c,
340 [4] = NULL,
341};
342
343static struct llc_station_state_trans llc_stat_down_state_trans_1 = {
344 .ev = llc_stat_ev_enable_with_dup_addr_check,
345 .next_state = LLC_STATION_STATE_DUP_ADDR_CHK,
346 .ev_actions = llc_stat_down_state_actions_1,
347};
348
349/* state transition for LLC_STATION_EV_ENABLE_WITHOUT_DUP_ADDR_CHECK event */
350static llc_station_action_t llc_stat_down_state_actions_2[] = {
351 [0] = llc_station_ac_report_status, /* STATION UP */
352 [1] = NULL,
353};
354
355static struct llc_station_state_trans llc_stat_down_state_trans_2 = {
356 .ev = llc_stat_ev_enable_without_dup_addr_check,
357 .next_state = LLC_STATION_STATE_UP,
358 .ev_actions = llc_stat_down_state_actions_2,
359};
360
361/* array of pointers; one to each transition */
362static struct llc_station_state_trans *llc_stat_dwn_state_trans[] = {
363 [0] = &llc_stat_down_state_trans_1,
364 [1] = &llc_stat_down_state_trans_2,
365 [2] = &llc_stat_state_trans_end,
366};
367
368/* UP STATE transitions */
369/* state transition for LLC_STATION_EV_DISABLE_REQ event */
370static llc_station_action_t llc_stat_up_state_actions_1[] = {
371 [0] = llc_station_ac_report_status, /* STATION DOWN */
372 [1] = NULL,
373};
374
375static struct llc_station_state_trans llc_stat_up_state_trans_1 = {
376 .ev = llc_stat_ev_disable_req,
377 .next_state = LLC_STATION_STATE_DOWN,
378 .ev_actions = llc_stat_up_state_actions_1,
379};
380
381/* state transition for LLC_STATION_EV_RX_NULL_DSAP_XID_C event */
382static llc_station_action_t llc_stat_up_state_actions_2[] = {
383 [0] = llc_station_ac_send_xid_r,
384 [1] = NULL,
385};
386
387static struct llc_station_state_trans llc_stat_up_state_trans_2 = {
388 .ev = llc_stat_ev_rx_null_dsap_xid_c,
389 .next_state = LLC_STATION_STATE_UP,
390 .ev_actions = llc_stat_up_state_actions_2,
391};
392
393/* state transition for LLC_STATION_EV_RX_NULL_DSAP_TEST_C event */
394static llc_station_action_t llc_stat_up_state_actions_3[] = {
395 [0] = llc_station_ac_send_test_r,
396 [1] = NULL,
397};
398
399static struct llc_station_state_trans llc_stat_up_state_trans_3 = {
400 .ev = llc_stat_ev_rx_null_dsap_test_c,
401 .next_state = LLC_STATION_STATE_UP,
402 .ev_actions = llc_stat_up_state_actions_3,
403};
404
405/* array of pointers; one to each transition */
406static struct llc_station_state_trans *llc_stat_up_state_trans [] = {
407 [0] = &llc_stat_up_state_trans_1,
408 [1] = &llc_stat_up_state_trans_2,
409 [2] = &llc_stat_up_state_trans_3,
410 [3] = &llc_stat_state_trans_end,
411};
412
413/* DUP ADDR CHK STATE transitions */
414/* state transition for LLC_STATION_EV_RX_NULL_DSAP_0_XID_R_XID_R_CNT_EQ
415 * event
416 */
417static llc_station_action_t llc_stat_dupaddr_state_actions_1[] = {
418 [0] = llc_station_ac_inc_xid_r_cnt_by_1,
419 [1] = NULL,
420};
421
422static struct llc_station_state_trans llc_stat_dupaddr_state_trans_1 = {
423 .ev = llc_stat_ev_rx_null_dsap_0_xid_r_xid_r_cnt_eq,
424 .next_state = LLC_STATION_STATE_DUP_ADDR_CHK,
425 .ev_actions = llc_stat_dupaddr_state_actions_1,
426};
427
428/* state transition for LLC_STATION_EV_RX_NULL_DSAP_1_XID_R_XID_R_CNT_EQ
429 * event
430 */
431static llc_station_action_t llc_stat_dupaddr_state_actions_2[] = {
432 [0] = llc_station_ac_report_status, /* DUPLICATE ADDRESS FOUND */
433 [1] = NULL,
434};
435
436static struct llc_station_state_trans llc_stat_dupaddr_state_trans_2 = {
437 .ev = llc_stat_ev_rx_null_dsap_1_xid_r_xid_r_cnt_eq,
438 .next_state = LLC_STATION_STATE_DOWN,
439 .ev_actions = llc_stat_dupaddr_state_actions_2,
440};
441
442/* state transition for LLC_STATION_EV_RX_NULL_DSAP_XID_C event */
443static llc_station_action_t llc_stat_dupaddr_state_actions_3[] = {
444 [0] = llc_station_ac_send_xid_r,
445 [1] = NULL,
446};
447
448static struct llc_station_state_trans llc_stat_dupaddr_state_trans_3 = {
449 .ev = llc_stat_ev_rx_null_dsap_xid_c,
450 .next_state = LLC_STATION_STATE_DUP_ADDR_CHK,
451 .ev_actions = llc_stat_dupaddr_state_actions_3,
452};
453
454/* state transition for LLC_STATION_EV_ACK_TMR_EXP_LT_RETRY_CNT_MAX_RETRY
455 * event
456 */
457static llc_station_action_t llc_stat_dupaddr_state_actions_4[] = {
458 [0] = llc_station_ac_start_ack_timer,
459 [1] = llc_station_ac_inc_retry_cnt_by_1,
460 [2] = llc_station_ac_set_xid_r_cnt_0,
461 [3] = llc_station_ac_send_null_dsap_xid_c,
462 [4] = NULL,
463};
464
465static struct llc_station_state_trans llc_stat_dupaddr_state_trans_4 = {
466 .ev = llc_stat_ev_ack_tmr_exp_lt_retry_cnt_max_retry,
467 .next_state = LLC_STATION_STATE_DUP_ADDR_CHK,
468 .ev_actions = llc_stat_dupaddr_state_actions_4,
469};
470
471/* state transition for LLC_STATION_EV_ACK_TMR_EXP_EQ_RETRY_CNT_MAX_RETRY
472 * event
473 */
474static llc_station_action_t llc_stat_dupaddr_state_actions_5[] = {
475 [0] = llc_station_ac_report_status, /* STATION UP */
476 [1] = NULL,
477};
478
479static struct llc_station_state_trans llc_stat_dupaddr_state_trans_5 = {
480 .ev = llc_stat_ev_ack_tmr_exp_eq_retry_cnt_max_retry,
481 .next_state = LLC_STATION_STATE_UP,
482 .ev_actions = llc_stat_dupaddr_state_actions_5,
483};
484
485/* state transition for LLC_STATION_EV_DISABLE_REQ event */
486static llc_station_action_t llc_stat_dupaddr_state_actions_6[] = {
487 [0] = llc_station_ac_report_status, /* STATION DOWN */
488 [1] = NULL,
489};
490
491static struct llc_station_state_trans llc_stat_dupaddr_state_trans_6 = {
492 .ev = llc_stat_ev_disable_req,
493 .next_state = LLC_STATION_STATE_DOWN,
494 .ev_actions = llc_stat_dupaddr_state_actions_6,
495};
496
497/* array of pointers; one to each transition */
498static struct llc_station_state_trans *llc_stat_dupaddr_state_trans[] = {
499 [0] = &llc_stat_dupaddr_state_trans_6, /* Request */
500 [1] = &llc_stat_dupaddr_state_trans_4, /* Timer */
501 [2] = &llc_stat_dupaddr_state_trans_5,
502 [3] = &llc_stat_dupaddr_state_trans_1, /* Receive frame */
503 [4] = &llc_stat_dupaddr_state_trans_2,
504 [5] = &llc_stat_dupaddr_state_trans_3,
505 [6] = &llc_stat_state_trans_end,
506};
507
508static struct llc_station_state
509 llc_station_state_table[LLC_NBR_STATION_STATES] = {
510 [LLC_STATION_STATE_DOWN - 1] = {
511 .curr_state = LLC_STATION_STATE_DOWN,
512 .transitions = llc_stat_dwn_state_trans,
513 },
514 [LLC_STATION_STATE_DUP_ADDR_CHK - 1] = {
515 .curr_state = LLC_STATION_STATE_DUP_ADDR_CHK,
516 .transitions = llc_stat_dupaddr_state_trans,
517 },
518 [LLC_STATION_STATE_UP - 1] = {
519 .curr_state = LLC_STATION_STATE_UP,
520 .transitions = llc_stat_up_state_trans,
521 },
522};
523
524/**
525 * llc_exec_station_trans_actions - executes actions for transition
526 * @trans: Address of the transition
527 * @skb: Address of the event that caused the transition
528 *
529 * Executes actions of a transition of the station state machine. Returns
530 * 0 if all actions complete successfully, nonzero otherwise.
531 */
532static u16 llc_exec_station_trans_actions(struct llc_station_state_trans *trans,
533 struct sk_buff *skb)
534{
535 u16 rc = 0;
536 llc_station_action_t *next_action = trans->ev_actions;
537
538 for (; next_action && *next_action; next_action++)
539 if ((*next_action)(skb))
540 rc = 1;
541 return rc;
542}
543
544/**
545 * llc_find_station_trans - finds transition for this event
546 * @skb: Address of the event
547 *
548 * Search thru events of the current state of the station until list
549 * exhausted or it's obvious that the event is not valid for the current
550 * state. Returns the address of the transition if cound, %NULL otherwise.
551 */
552static struct llc_station_state_trans *
553 llc_find_station_trans(struct sk_buff *skb)
554{
555 int i = 0;
556 struct llc_station_state_trans *rc = NULL;
557 struct llc_station_state_trans **next_trans;
558 struct llc_station_state *curr_state =
559 &llc_station_state_table[llc_main_station.state - 1];
560
561 for (next_trans = curr_state->transitions; next_trans[i]->ev; i++)
562 if (!next_trans[i]->ev(skb)) {
563 rc = next_trans[i];
564 break;
565 }
566 return rc;
567}
568
569/**
570 * llc_station_free_ev - frees an event
571 * @skb: Address of the event
572 *
573 * Frees an event.
574 */
575static void llc_station_free_ev(struct sk_buff *skb)
576{
577 struct llc_station_state_ev *ev = llc_station_ev(skb);
578
579 if (ev->type == LLC_STATION_EV_TYPE_PDU)
580 kfree_skb(skb);
581}
582
583/**
584 * llc_station_next_state - processes event and goes to the next state
585 * @skb: Address of the event
586 *
587 * Processes an event, executes any transitions related to that event and
588 * updates the state of the station.
589 */
590static u16 llc_station_next_state(struct sk_buff *skb)
591{
592 u16 rc = 1;
593 struct llc_station_state_trans *trans;
594
595 if (llc_main_station.state > LLC_NBR_STATION_STATES)
596 goto out;
597 trans = llc_find_station_trans(skb);
598 if (trans) {
599 /* got the state to which we next transition; perform the
600 * actions associated with this transition before actually
601 * transitioning to the next state
602 */
603 rc = llc_exec_station_trans_actions(trans, skb);
604 if (!rc)
605 /* transition station to next state if all actions
606 * execute successfully; done; wait for next event
607 */
608 llc_main_station.state = trans->next_state;
609 } else
610 /* event not recognized in current state; re-queue it for
611 * processing again at a later time; return failure
612 */
613 rc = 0;
614out:
615 llc_station_free_ev(skb);
616 return rc;
617}
618
619/**
620 * llc_station_service_events - service events in the queue
621 *
622 * Get an event from the station event queue (if any); attempt to service
623 * the event; if event serviced, get the next event (if any) on the event
624 * queue; if event not service, re-queue the event on the event queue and
625 * attempt to service the next event; when serviced all events in queue,
626 * finished; if don't transition to different state, just service all
627 * events once; if transition to new state, service all events again.
628 * Caller must hold llc_main_station.ev_q.lock.
629 */
630static void llc_station_service_events(void)
631{
632 struct sk_buff *skb;
633
634 while ((skb = skb_dequeue(&llc_main_station.ev_q.list)) != NULL)
635 llc_station_next_state(skb);
636}
637
638/**
639 * llc_station_state_process: queue event and try to process queue.
640 * @skb: Address of the event
641 *
642 * Queues an event (on the station event queue) for handling by the
643 * station state machine and attempts to process any queued-up events.
644 */
645static void llc_station_state_process(struct sk_buff *skb)
646{
647 spin_lock_bh(&llc_main_station.ev_q.lock);
648 skb_queue_tail(&llc_main_station.ev_q.list, skb);
649 llc_station_service_events();
650 spin_unlock_bh(&llc_main_station.ev_q.lock);
651}
652
653static void llc_station_ack_tmr_cb(unsigned long timeout_data)
654{
655 struct sk_buff *skb = alloc_skb(0, GFP_ATOMIC);
656
657 if (skb) {
658 struct llc_station_state_ev *ev = llc_station_ev(skb);
659
660 ev->type = LLC_STATION_EV_TYPE_ACK_TMR;
661 llc_station_state_process(skb);
662 }
663}
664
665/*
666 * llc_station_rcv - send received pdu to the station state machine
667 * @skb: received frame.
668 *
669 * Sends data unit to station state machine.
670 */
671static void llc_station_rcv(struct sk_buff *skb)
672{
673 struct llc_station_state_ev *ev = llc_station_ev(skb);
674
675 ev->type = LLC_STATION_EV_TYPE_PDU;
676 ev->reason = 0;
677 llc_station_state_process(skb);
678}
679
680int __init llc_station_init(void)
681{
682 u16 rc = -ENOBUFS;
683 struct sk_buff *skb;
684 struct llc_station_state_ev *ev;
685
686 skb_queue_head_init(&llc_main_station.mac_pdu_q);
687 skb_queue_head_init(&llc_main_station.ev_q.list);
688 spin_lock_init(&llc_main_station.ev_q.lock);
689 init_timer(&llc_main_station.ack_timer);
690 llc_main_station.ack_timer.data = (unsigned long)&llc_main_station;
691 llc_main_station.ack_timer.function = llc_station_ack_tmr_cb;
692
693 skb = alloc_skb(0, GFP_ATOMIC);
694 if (!skb)
695 goto out;
696 rc = 0;
697 llc_set_station_handler(llc_station_rcv);
698 ev = llc_station_ev(skb);
699 memset(ev, 0, sizeof(*ev));
700 llc_main_station.ack_timer.expires = jiffies + 3 * HZ;
701 llc_main_station.maximum_retry = 1;
702 llc_main_station.state = LLC_STATION_STATE_DOWN;
703 ev->type = LLC_STATION_EV_TYPE_SIMPLE;
704 ev->prim_type = LLC_STATION_EV_ENABLE_WITHOUT_DUP_ADDR_CHECK;
705 rc = llc_station_next_state(skb);
706out:
707 return rc;
708}
709
710void __exit llc_station_exit(void)
711{
712 llc_set_station_handler(NULL);
713}
generated by cgit v1.2.2 (git 2.25.0) at 2024-12-11 10:27:26 -0500