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[LLC]: Make llc_frame_alloc take a net_device as an argument
[deliverable/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 <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;
1d67e650 252 struct sk_buff *nskb = llc_alloc_frame(skb->dev);
1da177e4
LT		 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;
1d67e650 273 struct sk_buff* nskb = llc_alloc_frame(skb->dev);
1da177e4
LT		 274
275 if (!nskb)
276 goto out;
277 rc = 0;
1da177e4
LT		 278 llc_pdu_decode_sa(skb, mac_da);
279 llc_pdu_decode_ssap(skb, &dsap);
280 llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, 0, dsap, LLC_PDU_RSP);
281 llc_pdu_init_as_xid_rsp(nskb, LLC_XID_NULL_CLASS_2, 127);
282 rc = llc_mac_hdr_init(nskb, llc_station_mac_sa, mac_da);
283 if (rc)
284 goto free;
285 llc_station_send_pdu(nskb);
286out:
287 return rc;
288free:
289 kfree_skb(skb);
290 goto out;
291}
292
293static int llc_station_ac_send_test_r(struct sk_buff *skb)
294{
295 u8 mac_da[ETH_ALEN], dsap;
296 int rc = 1;
1d67e650 297 struct sk_buff *nskb = llc_alloc_frame(skb->dev);
1da177e4
LT		 298
299 if (!nskb)
300 goto out;
301 rc = 0;
1da177e4
LT		 302 llc_pdu_decode_sa(skb, mac_da);
303 llc_pdu_decode_ssap(skb, &dsap);
304 llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, 0, dsap, LLC_PDU_RSP);
305 llc_pdu_init_as_test_rsp(nskb, skb);
306 rc = llc_mac_hdr_init(nskb, llc_station_mac_sa, mac_da);
307 if (rc)
308 goto free;
309 llc_station_send_pdu(nskb);
310out:
311 return rc;
312free:
313 kfree_skb(skb);
314 goto out;
315}
316
317static int llc_station_ac_report_status(struct sk_buff *skb)
318{
319 return 0;
320}
321
322/* COMMON STATION STATE transitions */
323
324/* dummy last-transition indicator; common to all state transition groups
325 * last entry for this state
326 * all members are zeros, .bss zeroes it
327 */
328static struct llc_station_state_trans llc_stat_state_trans_end;
329
330/* DOWN STATE transitions */
331
332/* state transition for LLC_STATION_EV_ENABLE_WITH_DUP_ADDR_CHECK event */
333static llc_station_action_t llc_stat_down_state_actions_1[] = {
334 [0] = llc_station_ac_start_ack_timer,
335 [1] = llc_station_ac_set_retry_cnt_0,
336 [2] = llc_station_ac_set_xid_r_cnt_0,
337 [3] = llc_station_ac_send_null_dsap_xid_c,
338 [4] = NULL,
339};
340
341static struct llc_station_state_trans llc_stat_down_state_trans_1 = {
342 .ev = llc_stat_ev_enable_with_dup_addr_check,
343 .next_state = LLC_STATION_STATE_DUP_ADDR_CHK,
344 .ev_actions = llc_stat_down_state_actions_1,
345};
346
347/* state transition for LLC_STATION_EV_ENABLE_WITHOUT_DUP_ADDR_CHECK event */
348static llc_station_action_t llc_stat_down_state_actions_2[] = {
349 [0] = llc_station_ac_report_status, /* STATION UP */
350 [1] = NULL,
351};
352
353static struct llc_station_state_trans llc_stat_down_state_trans_2 = {
354 .ev = llc_stat_ev_enable_without_dup_addr_check,
355 .next_state = LLC_STATION_STATE_UP,
356 .ev_actions = llc_stat_down_state_actions_2,
357};
358
359/* array of pointers; one to each transition */
360static struct llc_station_state_trans *llc_stat_dwn_state_trans[] = {
361 [0] = &llc_stat_down_state_trans_1,
362 [1] = &llc_stat_down_state_trans_2,
363 [2] = &llc_stat_state_trans_end,
364};
365
366/* UP STATE transitions */
367/* state transition for LLC_STATION_EV_DISABLE_REQ event */
368static llc_station_action_t llc_stat_up_state_actions_1[] = {
369 [0] = llc_station_ac_report_status, /* STATION DOWN */
370 [1] = NULL,
371};
372
373static struct llc_station_state_trans llc_stat_up_state_trans_1 = {
374 .ev = llc_stat_ev_disable_req,
375 .next_state = LLC_STATION_STATE_DOWN,
376 .ev_actions = llc_stat_up_state_actions_1,
377};
378
379/* state transition for LLC_STATION_EV_RX_NULL_DSAP_XID_C event */
380static llc_station_action_t llc_stat_up_state_actions_2[] = {
381 [0] = llc_station_ac_send_xid_r,
382 [1] = NULL,
383};
384
385static struct llc_station_state_trans llc_stat_up_state_trans_2 = {
386 .ev = llc_stat_ev_rx_null_dsap_xid_c,
387 .next_state = LLC_STATION_STATE_UP,
388 .ev_actions = llc_stat_up_state_actions_2,
389};
390
391/* state transition for LLC_STATION_EV_RX_NULL_DSAP_TEST_C event */
392static llc_station_action_t llc_stat_up_state_actions_3[] = {
393 [0] = llc_station_ac_send_test_r,
394 [1] = NULL,
395};
396
397static struct llc_station_state_trans llc_stat_up_state_trans_3 = {
398 .ev = llc_stat_ev_rx_null_dsap_test_c,
399 .next_state = LLC_STATION_STATE_UP,
400 .ev_actions = llc_stat_up_state_actions_3,
401};
402
403/* array of pointers; one to each transition */
404static struct llc_station_state_trans *llc_stat_up_state_trans [] = {
405 [0] = &llc_stat_up_state_trans_1,
406 [1] = &llc_stat_up_state_trans_2,
407 [2] = &llc_stat_up_state_trans_3,
408 [3] = &llc_stat_state_trans_end,
409};
410
411/* DUP ADDR CHK STATE transitions */
412/* state transition for LLC_STATION_EV_RX_NULL_DSAP_0_XID_R_XID_R_CNT_EQ
413 * event
414 */
415static llc_station_action_t llc_stat_dupaddr_state_actions_1[] = {
416 [0] = llc_station_ac_inc_xid_r_cnt_by_1,
417 [1] = NULL,
418};
419
420static struct llc_station_state_trans llc_stat_dupaddr_state_trans_1 = {
421 .ev = llc_stat_ev_rx_null_dsap_0_xid_r_xid_r_cnt_eq,
422 .next_state = LLC_STATION_STATE_DUP_ADDR_CHK,
423 .ev_actions = llc_stat_dupaddr_state_actions_1,
424};
425
426/* state transition for LLC_STATION_EV_RX_NULL_DSAP_1_XID_R_XID_R_CNT_EQ
427 * event
428 */
429static llc_station_action_t llc_stat_dupaddr_state_actions_2[] = {
430 [0] = llc_station_ac_report_status, /* DUPLICATE ADDRESS FOUND */
431 [1] = NULL,
432};
433
434static struct llc_station_state_trans llc_stat_dupaddr_state_trans_2 = {
435 .ev = llc_stat_ev_rx_null_dsap_1_xid_r_xid_r_cnt_eq,
436 .next_state = LLC_STATION_STATE_DOWN,
437 .ev_actions = llc_stat_dupaddr_state_actions_2,
438};
439
440/* state transition for LLC_STATION_EV_RX_NULL_DSAP_XID_C event */
441static llc_station_action_t llc_stat_dupaddr_state_actions_3[] = {
442 [0] = llc_station_ac_send_xid_r,
443 [1] = NULL,
444};
445
446static struct llc_station_state_trans llc_stat_dupaddr_state_trans_3 = {
447 .ev = llc_stat_ev_rx_null_dsap_xid_c,
448 .next_state = LLC_STATION_STATE_DUP_ADDR_CHK,
449 .ev_actions = llc_stat_dupaddr_state_actions_3,
450};
451
452/* state transition for LLC_STATION_EV_ACK_TMR_EXP_LT_RETRY_CNT_MAX_RETRY
453 * event
454 */
455static llc_station_action_t llc_stat_dupaddr_state_actions_4[] = {
456 [0] = llc_station_ac_start_ack_timer,
457 [1] = llc_station_ac_inc_retry_cnt_by_1,
458 [2] = llc_station_ac_set_xid_r_cnt_0,
459 [3] = llc_station_ac_send_null_dsap_xid_c,
460 [4] = NULL,
461};
462
463static struct llc_station_state_trans llc_stat_dupaddr_state_trans_4 = {
464 .ev = llc_stat_ev_ack_tmr_exp_lt_retry_cnt_max_retry,
465 .next_state = LLC_STATION_STATE_DUP_ADDR_CHK,
466 .ev_actions = llc_stat_dupaddr_state_actions_4,
467};
468
469/* state transition for LLC_STATION_EV_ACK_TMR_EXP_EQ_RETRY_CNT_MAX_RETRY
470 * event
471 */
472static llc_station_action_t llc_stat_dupaddr_state_actions_5[] = {
473 [0] = llc_station_ac_report_status, /* STATION UP */
474 [1] = NULL,
475};
476
477static struct llc_station_state_trans llc_stat_dupaddr_state_trans_5 = {
478 .ev = llc_stat_ev_ack_tmr_exp_eq_retry_cnt_max_retry,
479 .next_state = LLC_STATION_STATE_UP,
480 .ev_actions = llc_stat_dupaddr_state_actions_5,
481};
482
483/* state transition for LLC_STATION_EV_DISABLE_REQ event */
484static llc_station_action_t llc_stat_dupaddr_state_actions_6[] = {
485 [0] = llc_station_ac_report_status, /* STATION DOWN */
486 [1] = NULL,
487};
488
489static struct llc_station_state_trans llc_stat_dupaddr_state_trans_6 = {
490 .ev = llc_stat_ev_disable_req,
491 .next_state = LLC_STATION_STATE_DOWN,
492 .ev_actions = llc_stat_dupaddr_state_actions_6,
493};
494
495/* array of pointers; one to each transition */
496static struct llc_station_state_trans *llc_stat_dupaddr_state_trans[] = {
497 [0] = &llc_stat_dupaddr_state_trans_6, /* Request */
498 [1] = &llc_stat_dupaddr_state_trans_4, /* Timer */
499 [2] = &llc_stat_dupaddr_state_trans_5,
500 [3] = &llc_stat_dupaddr_state_trans_1, /* Receive frame */
501 [4] = &llc_stat_dupaddr_state_trans_2,
502 [5] = &llc_stat_dupaddr_state_trans_3,
503 [6] = &llc_stat_state_trans_end,
504};
505
506static struct llc_station_state
507 llc_station_state_table[LLC_NBR_STATION_STATES] = {
508 [LLC_STATION_STATE_DOWN - 1] = {
509 .curr_state = LLC_STATION_STATE_DOWN,
510 .transitions = llc_stat_dwn_state_trans,
511 },
512 [LLC_STATION_STATE_DUP_ADDR_CHK - 1] = {
513 .curr_state = LLC_STATION_STATE_DUP_ADDR_CHK,
514 .transitions = llc_stat_dupaddr_state_trans,
515 },
516 [LLC_STATION_STATE_UP - 1] = {
517 .curr_state = LLC_STATION_STATE_UP,
518 .transitions = llc_stat_up_state_trans,
519 },
520};
521
522/**
523 * llc_exec_station_trans_actions - executes actions for transition
524 * @trans: Address of the transition
525 * @skb: Address of the event that caused the transition
526 *
527 * Executes actions of a transition of the station state machine. Returns
528 * 0 if all actions complete successfully, nonzero otherwise.
529 */
530static u16 llc_exec_station_trans_actions(struct llc_station_state_trans *trans,
531 struct sk_buff *skb)
532{
533 u16 rc = 0;
534 llc_station_action_t *next_action = trans->ev_actions;
535
536 for (; next_action && *next_action; next_action++)
537 if ((*next_action)(skb))
538 rc = 1;
539 return rc;
540}
541
542/**
543 * llc_find_station_trans - finds transition for this event
544 * @skb: Address of the event
545 *
546 * Search thru events of the current state of the station until list
547 * exhausted or it's obvious that the event is not valid for the current
548 * state. Returns the address of the transition if cound, %NULL otherwise.
549 */
550static struct llc_station_state_trans *
551 llc_find_station_trans(struct sk_buff *skb)
552{
553 int i = 0;
554 struct llc_station_state_trans *rc = NULL;
555 struct llc_station_state_trans **next_trans;
556 struct llc_station_state *curr_state =
557 &llc_station_state_table[llc_main_station.state - 1];
558
559 for (next_trans = curr_state->transitions; next_trans[i]->ev; i++)
560 if (!next_trans[i]->ev(skb)) {
561 rc = next_trans[i];
562 break;
563 }
564 return rc;
565}
566
567/**
568 * llc_station_free_ev - frees an event
569 * @skb: Address of the event
570 *
571 * Frees an event.
572 */
573static void llc_station_free_ev(struct sk_buff *skb)
574{
575 struct llc_station_state_ev *ev = llc_station_ev(skb);
576
577 if (ev->type == LLC_STATION_EV_TYPE_PDU)
578 kfree_skb(skb);
579}
580
581/**
582 * llc_station_next_state - processes event and goes to the next state
583 * @skb: Address of the event
584 *
585 * Processes an event, executes any transitions related to that event and
586 * updates the state of the station.
587 */
588static u16 llc_station_next_state(struct sk_buff *skb)
589{
590 u16 rc = 1;
591 struct llc_station_state_trans *trans;
592
593 if (llc_main_station.state > LLC_NBR_STATION_STATES)
594 goto out;
595 trans = llc_find_station_trans(skb);
596 if (trans) {
597 /* got the state to which we next transition; perform the
598 * actions associated with this transition before actually
599 * transitioning to the next state
600 */
601 rc = llc_exec_station_trans_actions(trans, skb);
602 if (!rc)
603 /* transition station to next state if all actions
604 * execute successfully; done; wait for next event
605 */
606 llc_main_station.state = trans->next_state;
607 } else
608 /* event not recognized in current state; re-queue it for
609 * processing again at a later time; return failure
610 */
611 rc = 0;
612out:
613 llc_station_free_ev(skb);
614 return rc;
615}
616
617/**
618 * llc_station_service_events - service events in the queue
619 *
620 * Get an event from the station event queue (if any); attempt to service
621 * the event; if event serviced, get the next event (if any) on the event
622 * queue; if event not service, re-queue the event on the event queue and
623 * attempt to service the next event; when serviced all events in queue,
624 * finished; if don't transition to different state, just service all
625 * events once; if transition to new state, service all events again.
626 * Caller must hold llc_main_station.ev_q.lock.
627 */
628static void llc_station_service_events(void)
629{
630 struct sk_buff *skb;
631
632 while ((skb = skb_dequeue(&llc_main_station.ev_q.list)) != NULL)
633 llc_station_next_state(skb);
634}
635
636/**
637 * llc_station_state_process: queue event and try to process queue.
638 * @skb: Address of the event
639 *
640 * Queues an event (on the station event queue) for handling by the
641 * station state machine and attempts to process any queued-up events.
642 */
643static void llc_station_state_process(struct sk_buff *skb)
644{
645 spin_lock_bh(&llc_main_station.ev_q.lock);
646 skb_queue_tail(&llc_main_station.ev_q.list, skb);
647 llc_station_service_events();
648 spin_unlock_bh(&llc_main_station.ev_q.lock);
649}
650
651static void llc_station_ack_tmr_cb(unsigned long timeout_data)
652{
653 struct sk_buff *skb = alloc_skb(0, GFP_ATOMIC);
654
655 if (skb) {
656 struct llc_station_state_ev *ev = llc_station_ev(skb);
657
658 ev->type = LLC_STATION_EV_TYPE_ACK_TMR;
659 llc_station_state_process(skb);
660 }
661}
662
663/*
664 * llc_station_rcv - send received pdu to the station state machine
665 * @skb: received frame.
666 *
667 * Sends data unit to station state machine.
668 */
669static void llc_station_rcv(struct sk_buff *skb)
670{
671 struct llc_station_state_ev *ev = llc_station_ev(skb);
672
673 ev->type = LLC_STATION_EV_TYPE_PDU;
674 ev->reason = 0;
675 llc_station_state_process(skb);
676}
677
678int __init llc_station_init(void)
679{
680 u16 rc = -ENOBUFS;
681 struct sk_buff *skb;
682 struct llc_station_state_ev *ev;
683
684 skb_queue_head_init(&llc_main_station.mac_pdu_q);
685 skb_queue_head_init(&llc_main_station.ev_q.list);
686 spin_lock_init(&llc_main_station.ev_q.lock);
687 init_timer(&llc_main_station.ack_timer);
688 llc_main_station.ack_timer.data = (unsigned long)&llc_main_station;
689 llc_main_station.ack_timer.function = llc_station_ack_tmr_cb;
690
691 skb = alloc_skb(0, GFP_ATOMIC);
692 if (!skb)
693 goto out;
694 rc = 0;
695 llc_set_station_handler(llc_station_rcv);
696 ev = llc_station_ev(skb);
697 memset(ev, 0, sizeof(*ev));
698 llc_main_station.ack_timer.expires = jiffies + 3 * HZ;
699 llc_main_station.maximum_retry = 1;
700 llc_main_station.state = LLC_STATION_STATE_DOWN;
701 ev->type = LLC_STATION_EV_TYPE_SIMPLE;
702 ev->prim_type = LLC_STATION_EV_ENABLE_WITHOUT_DUP_ADDR_CHECK;
703 rc = llc_station_next_state(skb);
704out:
705 return rc;
706}
707
708void __exit llc_station_exit(void)
709{
710 llc_set_station_handler(NULL);
711}
Linux kernel - Deliverables
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