blob: f37dbf8ef126a1cdc8464d98f1320660f664a9f6 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
Arnaldo Carvalho de Melo590232a2005-09-22 04:30:44 -030053#define LLC_STATION_ACK_TIME (3 * HZ)
54
55int sysctl_llc_station_ack_timeout = LLC_STATION_ACK_TIME;
56
Linus Torvalds1da177e2005-04-16 15:20:36 -070057/* Types of events (possible values in 'ev->type') */
58#define LLC_STATION_EV_TYPE_SIMPLE 1
59#define LLC_STATION_EV_TYPE_CONDITION 2
60#define LLC_STATION_EV_TYPE_PRIM 3
61#define LLC_STATION_EV_TYPE_PDU 4 /* command/response PDU */
62#define LLC_STATION_EV_TYPE_ACK_TMR 5
63#define LLC_STATION_EV_TYPE_RPT_STATUS 6
64
65/* Events */
66#define LLC_STATION_EV_ENABLE_WITH_DUP_ADDR_CHECK 1
67#define LLC_STATION_EV_ENABLE_WITHOUT_DUP_ADDR_CHECK 2
68#define LLC_STATION_EV_ACK_TMR_EXP_LT_RETRY_CNT_MAX_RETRY 3
69#define LLC_STATION_EV_ACK_TMR_EXP_EQ_RETRY_CNT_MAX_RETRY 4
70#define LLC_STATION_EV_RX_NULL_DSAP_XID_C 5
71#define LLC_STATION_EV_RX_NULL_DSAP_0_XID_R_XID_R_CNT_EQ 6
72#define LLC_STATION_EV_RX_NULL_DSAP_1_XID_R_XID_R_CNT_EQ 7
73#define LLC_STATION_EV_RX_NULL_DSAP_TEST_C 8
74#define LLC_STATION_EV_DISABLE_REQ 9
75
76struct llc_station_state_ev {
77 u8 type;
78 u8 prim;
79 u8 prim_type;
80 u8 reason;
81 struct list_head node; /* node in station->ev_q.list */
82};
83
84static __inline__ struct llc_station_state_ev *
85 llc_station_ev(struct sk_buff *skb)
86{
87 return (struct llc_station_state_ev *)skb->cb;
88}
89
90typedef int (*llc_station_ev_t)(struct sk_buff *skb);
91
92#define LLC_STATION_STATE_DOWN 1 /* initial state */
93#define LLC_STATION_STATE_DUP_ADDR_CHK 2
94#define LLC_STATION_STATE_UP 3
95
96#define LLC_NBR_STATION_STATES 3 /* size of state table */
97
98typedef int (*llc_station_action_t)(struct sk_buff *skb);
99
100/* Station component state table structure */
101struct llc_station_state_trans {
102 llc_station_ev_t ev;
103 u8 next_state;
104 llc_station_action_t *ev_actions;
105};
106
107struct llc_station_state {
108 u8 curr_state;
109 struct llc_station_state_trans **transitions;
110};
111
112static struct llc_station llc_main_station;
113
114static int llc_stat_ev_enable_with_dup_addr_check(struct sk_buff *skb)
115{
116 struct llc_station_state_ev *ev = llc_station_ev(skb);
117
118 return ev->type == LLC_STATION_EV_TYPE_SIMPLE &&
119 ev->prim_type ==
120 LLC_STATION_EV_ENABLE_WITH_DUP_ADDR_CHECK ? 0 : 1;
121}
122
123static int llc_stat_ev_enable_without_dup_addr_check(struct sk_buff *skb)
124{
125 struct llc_station_state_ev *ev = llc_station_ev(skb);
126
127 return ev->type == LLC_STATION_EV_TYPE_SIMPLE &&
128 ev->prim_type ==
129 LLC_STATION_EV_ENABLE_WITHOUT_DUP_ADDR_CHECK ? 0 : 1;
130}
131
132static int llc_stat_ev_ack_tmr_exp_lt_retry_cnt_max_retry(struct sk_buff *skb)
133{
134 struct llc_station_state_ev *ev = llc_station_ev(skb);
135
136 return ev->type == LLC_STATION_EV_TYPE_ACK_TMR &&
137 llc_main_station.retry_count <
138 llc_main_station.maximum_retry ? 0 : 1;
139}
140
141static int llc_stat_ev_ack_tmr_exp_eq_retry_cnt_max_retry(struct sk_buff *skb)
142{
143 struct llc_station_state_ev *ev = llc_station_ev(skb);
144
145 return ev->type == LLC_STATION_EV_TYPE_ACK_TMR &&
146 llc_main_station.retry_count ==
147 llc_main_station.maximum_retry ? 0 : 1;
148}
149
150static int llc_stat_ev_rx_null_dsap_xid_c(struct sk_buff *skb)
151{
152 struct llc_station_state_ev *ev = llc_station_ev(skb);
153 struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
154
155 return ev->type == LLC_STATION_EV_TYPE_PDU &&
156 LLC_PDU_IS_CMD(pdu) && /* command PDU */
157 LLC_PDU_TYPE_IS_U(pdu) && /* U type PDU */
158 LLC_U_PDU_CMD(pdu) == LLC_1_PDU_CMD_XID &&
159 !pdu->dsap ? 0 : 1; /* NULL DSAP value */
160}
161
162static int llc_stat_ev_rx_null_dsap_0_xid_r_xid_r_cnt_eq(struct sk_buff *skb)
163{
164 struct llc_station_state_ev *ev = llc_station_ev(skb);
165 struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
166
167 return ev->type == LLC_STATION_EV_TYPE_PDU &&
168 LLC_PDU_IS_RSP(pdu) && /* response PDU */
169 LLC_PDU_TYPE_IS_U(pdu) && /* U type PDU */
170 LLC_U_PDU_RSP(pdu) == LLC_1_PDU_CMD_XID &&
171 !pdu->dsap && /* NULL DSAP value */
172 !llc_main_station.xid_r_count ? 0 : 1;
173}
174
175static int llc_stat_ev_rx_null_dsap_1_xid_r_xid_r_cnt_eq(struct sk_buff *skb)
176{
177 struct llc_station_state_ev *ev = llc_station_ev(skb);
178 struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
179
180 return ev->type == LLC_STATION_EV_TYPE_PDU &&
181 LLC_PDU_IS_RSP(pdu) && /* response PDU */
182 LLC_PDU_TYPE_IS_U(pdu) && /* U type PDU */
183 LLC_U_PDU_RSP(pdu) == LLC_1_PDU_CMD_XID &&
184 !pdu->dsap && /* NULL DSAP value */
185 llc_main_station.xid_r_count == 1 ? 0 : 1;
186}
187
188static int llc_stat_ev_rx_null_dsap_test_c(struct sk_buff *skb)
189{
190 struct llc_station_state_ev *ev = llc_station_ev(skb);
191 struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
192
193 return ev->type == LLC_STATION_EV_TYPE_PDU &&
194 LLC_PDU_IS_CMD(pdu) && /* command PDU */
195 LLC_PDU_TYPE_IS_U(pdu) && /* U type PDU */
196 LLC_U_PDU_CMD(pdu) == LLC_1_PDU_CMD_TEST &&
197 !pdu->dsap ? 0 : 1; /* NULL DSAP */
198}
199
200static int llc_stat_ev_disable_req(struct sk_buff *skb)
201{
202 struct llc_station_state_ev *ev = llc_station_ev(skb);
203
204 return ev->type == LLC_STATION_EV_TYPE_PRIM &&
205 ev->prim == LLC_DISABLE_PRIM &&
206 ev->prim_type == LLC_PRIM_TYPE_REQ ? 0 : 1;
207}
208
209/**
210 * llc_station_send_pdu - queues PDU to send
211 * @skb: Address of the PDU
212 *
213 * Queues a PDU to send to the MAC layer.
214 */
215static void llc_station_send_pdu(struct sk_buff *skb)
216{
217 skb_queue_tail(&llc_main_station.mac_pdu_q, skb);
218 while ((skb = skb_dequeue(&llc_main_station.mac_pdu_q)) != NULL)
219 if (dev_queue_xmit(skb))
220 break;
221}
222
223static int llc_station_ac_start_ack_timer(struct sk_buff *skb)
224{
Arnaldo Carvalho de Melo590232a2005-09-22 04:30:44 -0300225 mod_timer(&llc_main_station.ack_timer,
226 jiffies + sysctl_llc_station_ack_timeout);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227 return 0;
228}
229
230static int llc_station_ac_set_retry_cnt_0(struct sk_buff *skb)
231{
232 llc_main_station.retry_count = 0;
233 return 0;
234}
235
236static int llc_station_ac_inc_retry_cnt_by_1(struct sk_buff *skb)
237{
238 llc_main_station.retry_count++;
239 return 0;
240}
241
242static int llc_station_ac_set_xid_r_cnt_0(struct sk_buff *skb)
243{
244 llc_main_station.xid_r_count = 0;
245 return 0;
246}
247
248static int llc_station_ac_inc_xid_r_cnt_by_1(struct sk_buff *skb)
249{
250 llc_main_station.xid_r_count++;
251 return 0;
252}
253
254static int llc_station_ac_send_null_dsap_xid_c(struct sk_buff *skb)
255{
256 int rc = 1;
Arnaldo Carvalho de Melod3894242005-09-22 07:57:21 -0300257 struct sk_buff *nskb = llc_alloc_frame(NULL, skb->dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258
259 if (!nskb)
260 goto out;
261 llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, 0, 0, LLC_PDU_CMD);
262 llc_pdu_init_as_xid_cmd(nskb, LLC_XID_NULL_CLASS_2, 127);
263 rc = llc_mac_hdr_init(nskb, llc_station_mac_sa, llc_station_mac_sa);
Arnaldo Carvalho de Melo249ff1c2005-09-22 04:32:10 -0300264 if (unlikely(rc))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265 goto free;
266 llc_station_send_pdu(nskb);
267out:
268 return rc;
269free:
270 kfree_skb(skb);
271 goto out;
272}
273
274static int llc_station_ac_send_xid_r(struct sk_buff *skb)
275{
276 u8 mac_da[ETH_ALEN], dsap;
277 int rc = 1;
Arnaldo Carvalho de Melod3894242005-09-22 07:57:21 -0300278 struct sk_buff* nskb = llc_alloc_frame(NULL, skb->dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279
280 if (!nskb)
281 goto out;
282 rc = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283 llc_pdu_decode_sa(skb, mac_da);
284 llc_pdu_decode_ssap(skb, &dsap);
285 llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, 0, dsap, LLC_PDU_RSP);
286 llc_pdu_init_as_xid_rsp(nskb, LLC_XID_NULL_CLASS_2, 127);
287 rc = llc_mac_hdr_init(nskb, llc_station_mac_sa, mac_da);
Arnaldo Carvalho de Melo249ff1c2005-09-22 04:32:10 -0300288 if (unlikely(rc))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289 goto free;
290 llc_station_send_pdu(nskb);
291out:
292 return rc;
293free:
294 kfree_skb(skb);
295 goto out;
296}
297
298static int llc_station_ac_send_test_r(struct sk_buff *skb)
299{
300 u8 mac_da[ETH_ALEN], dsap;
301 int rc = 1;
Arnaldo Carvalho de Melod3894242005-09-22 07:57:21 -0300302 struct sk_buff *nskb = llc_alloc_frame(NULL, skb->dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303
304 if (!nskb)
305 goto out;
306 rc = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307 llc_pdu_decode_sa(skb, mac_da);
308 llc_pdu_decode_ssap(skb, &dsap);
309 llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, 0, dsap, LLC_PDU_RSP);
310 llc_pdu_init_as_test_rsp(nskb, skb);
311 rc = llc_mac_hdr_init(nskb, llc_station_mac_sa, mac_da);
Arnaldo Carvalho de Melo249ff1c2005-09-22 04:32:10 -0300312 if (unlikely(rc))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313 goto free;
314 llc_station_send_pdu(nskb);
315out:
316 return rc;
317free:
318 kfree_skb(skb);
319 goto out;
320}
321
322static int llc_station_ac_report_status(struct sk_buff *skb)
323{
324 return 0;
325}
326
327/* COMMON STATION STATE transitions */
328
329/* dummy last-transition indicator; common to all state transition groups
330 * last entry for this state
331 * all members are zeros, .bss zeroes it
332 */
333static struct llc_station_state_trans llc_stat_state_trans_end;
334
335/* DOWN STATE transitions */
336
337/* state transition for LLC_STATION_EV_ENABLE_WITH_DUP_ADDR_CHECK event */
338static llc_station_action_t llc_stat_down_state_actions_1[] = {
339 [0] = llc_station_ac_start_ack_timer,
340 [1] = llc_station_ac_set_retry_cnt_0,
341 [2] = llc_station_ac_set_xid_r_cnt_0,
342 [3] = llc_station_ac_send_null_dsap_xid_c,
343 [4] = NULL,
344};
345
346static struct llc_station_state_trans llc_stat_down_state_trans_1 = {
347 .ev = llc_stat_ev_enable_with_dup_addr_check,
348 .next_state = LLC_STATION_STATE_DUP_ADDR_CHK,
349 .ev_actions = llc_stat_down_state_actions_1,
350};
351
352/* state transition for LLC_STATION_EV_ENABLE_WITHOUT_DUP_ADDR_CHECK event */
353static llc_station_action_t llc_stat_down_state_actions_2[] = {
354 [0] = llc_station_ac_report_status, /* STATION UP */
355 [1] = NULL,
356};
357
358static struct llc_station_state_trans llc_stat_down_state_trans_2 = {
359 .ev = llc_stat_ev_enable_without_dup_addr_check,
360 .next_state = LLC_STATION_STATE_UP,
361 .ev_actions = llc_stat_down_state_actions_2,
362};
363
364/* array of pointers; one to each transition */
365static struct llc_station_state_trans *llc_stat_dwn_state_trans[] = {
366 [0] = &llc_stat_down_state_trans_1,
367 [1] = &llc_stat_down_state_trans_2,
368 [2] = &llc_stat_state_trans_end,
369};
370
371/* UP STATE transitions */
372/* state transition for LLC_STATION_EV_DISABLE_REQ event */
373static llc_station_action_t llc_stat_up_state_actions_1[] = {
374 [0] = llc_station_ac_report_status, /* STATION DOWN */
375 [1] = NULL,
376};
377
378static struct llc_station_state_trans llc_stat_up_state_trans_1 = {
379 .ev = llc_stat_ev_disable_req,
380 .next_state = LLC_STATION_STATE_DOWN,
381 .ev_actions = llc_stat_up_state_actions_1,
382};
383
384/* state transition for LLC_STATION_EV_RX_NULL_DSAP_XID_C event */
385static llc_station_action_t llc_stat_up_state_actions_2[] = {
386 [0] = llc_station_ac_send_xid_r,
387 [1] = NULL,
388};
389
390static struct llc_station_state_trans llc_stat_up_state_trans_2 = {
391 .ev = llc_stat_ev_rx_null_dsap_xid_c,
392 .next_state = LLC_STATION_STATE_UP,
393 .ev_actions = llc_stat_up_state_actions_2,
394};
395
396/* state transition for LLC_STATION_EV_RX_NULL_DSAP_TEST_C event */
397static llc_station_action_t llc_stat_up_state_actions_3[] = {
398 [0] = llc_station_ac_send_test_r,
399 [1] = NULL,
400};
401
402static struct llc_station_state_trans llc_stat_up_state_trans_3 = {
403 .ev = llc_stat_ev_rx_null_dsap_test_c,
404 .next_state = LLC_STATION_STATE_UP,
405 .ev_actions = llc_stat_up_state_actions_3,
406};
407
408/* array of pointers; one to each transition */
409static struct llc_station_state_trans *llc_stat_up_state_trans [] = {
410 [0] = &llc_stat_up_state_trans_1,
411 [1] = &llc_stat_up_state_trans_2,
412 [2] = &llc_stat_up_state_trans_3,
413 [3] = &llc_stat_state_trans_end,
414};
415
416/* DUP ADDR CHK STATE transitions */
417/* state transition for LLC_STATION_EV_RX_NULL_DSAP_0_XID_R_XID_R_CNT_EQ
418 * event
419 */
420static llc_station_action_t llc_stat_dupaddr_state_actions_1[] = {
421 [0] = llc_station_ac_inc_xid_r_cnt_by_1,
422 [1] = NULL,
423};
424
425static struct llc_station_state_trans llc_stat_dupaddr_state_trans_1 = {
426 .ev = llc_stat_ev_rx_null_dsap_0_xid_r_xid_r_cnt_eq,
427 .next_state = LLC_STATION_STATE_DUP_ADDR_CHK,
428 .ev_actions = llc_stat_dupaddr_state_actions_1,
429};
430
431/* state transition for LLC_STATION_EV_RX_NULL_DSAP_1_XID_R_XID_R_CNT_EQ
432 * event
433 */
434static llc_station_action_t llc_stat_dupaddr_state_actions_2[] = {
435 [0] = llc_station_ac_report_status, /* DUPLICATE ADDRESS FOUND */
436 [1] = NULL,
437};
438
439static struct llc_station_state_trans llc_stat_dupaddr_state_trans_2 = {
440 .ev = llc_stat_ev_rx_null_dsap_1_xid_r_xid_r_cnt_eq,
441 .next_state = LLC_STATION_STATE_DOWN,
442 .ev_actions = llc_stat_dupaddr_state_actions_2,
443};
444
445/* state transition for LLC_STATION_EV_RX_NULL_DSAP_XID_C event */
446static llc_station_action_t llc_stat_dupaddr_state_actions_3[] = {
447 [0] = llc_station_ac_send_xid_r,
448 [1] = NULL,
449};
450
451static struct llc_station_state_trans llc_stat_dupaddr_state_trans_3 = {
452 .ev = llc_stat_ev_rx_null_dsap_xid_c,
453 .next_state = LLC_STATION_STATE_DUP_ADDR_CHK,
454 .ev_actions = llc_stat_dupaddr_state_actions_3,
455};
456
457/* state transition for LLC_STATION_EV_ACK_TMR_EXP_LT_RETRY_CNT_MAX_RETRY
458 * event
459 */
460static llc_station_action_t llc_stat_dupaddr_state_actions_4[] = {
461 [0] = llc_station_ac_start_ack_timer,
462 [1] = llc_station_ac_inc_retry_cnt_by_1,
463 [2] = llc_station_ac_set_xid_r_cnt_0,
464 [3] = llc_station_ac_send_null_dsap_xid_c,
465 [4] = NULL,
466};
467
468static struct llc_station_state_trans llc_stat_dupaddr_state_trans_4 = {
469 .ev = llc_stat_ev_ack_tmr_exp_lt_retry_cnt_max_retry,
470 .next_state = LLC_STATION_STATE_DUP_ADDR_CHK,
471 .ev_actions = llc_stat_dupaddr_state_actions_4,
472};
473
474/* state transition for LLC_STATION_EV_ACK_TMR_EXP_EQ_RETRY_CNT_MAX_RETRY
475 * event
476 */
477static llc_station_action_t llc_stat_dupaddr_state_actions_5[] = {
478 [0] = llc_station_ac_report_status, /* STATION UP */
479 [1] = NULL,
480};
481
482static struct llc_station_state_trans llc_stat_dupaddr_state_trans_5 = {
483 .ev = llc_stat_ev_ack_tmr_exp_eq_retry_cnt_max_retry,
484 .next_state = LLC_STATION_STATE_UP,
485 .ev_actions = llc_stat_dupaddr_state_actions_5,
486};
487
488/* state transition for LLC_STATION_EV_DISABLE_REQ event */
489static llc_station_action_t llc_stat_dupaddr_state_actions_6[] = {
490 [0] = llc_station_ac_report_status, /* STATION DOWN */
491 [1] = NULL,
492};
493
494static struct llc_station_state_trans llc_stat_dupaddr_state_trans_6 = {
495 .ev = llc_stat_ev_disable_req,
496 .next_state = LLC_STATION_STATE_DOWN,
497 .ev_actions = llc_stat_dupaddr_state_actions_6,
498};
499
500/* array of pointers; one to each transition */
501static struct llc_station_state_trans *llc_stat_dupaddr_state_trans[] = {
502 [0] = &llc_stat_dupaddr_state_trans_6, /* Request */
503 [1] = &llc_stat_dupaddr_state_trans_4, /* Timer */
504 [2] = &llc_stat_dupaddr_state_trans_5,
505 [3] = &llc_stat_dupaddr_state_trans_1, /* Receive frame */
506 [4] = &llc_stat_dupaddr_state_trans_2,
507 [5] = &llc_stat_dupaddr_state_trans_3,
508 [6] = &llc_stat_state_trans_end,
509};
510
511static struct llc_station_state
512 llc_station_state_table[LLC_NBR_STATION_STATES] = {
513 [LLC_STATION_STATE_DOWN - 1] = {
514 .curr_state = LLC_STATION_STATE_DOWN,
515 .transitions = llc_stat_dwn_state_trans,
516 },
517 [LLC_STATION_STATE_DUP_ADDR_CHK - 1] = {
518 .curr_state = LLC_STATION_STATE_DUP_ADDR_CHK,
519 .transitions = llc_stat_dupaddr_state_trans,
520 },
521 [LLC_STATION_STATE_UP - 1] = {
522 .curr_state = LLC_STATION_STATE_UP,
523 .transitions = llc_stat_up_state_trans,
524 },
525};
526
527/**
528 * llc_exec_station_trans_actions - executes actions for transition
529 * @trans: Address of the transition
530 * @skb: Address of the event that caused the transition
531 *
532 * Executes actions of a transition of the station state machine. Returns
533 * 0 if all actions complete successfully, nonzero otherwise.
534 */
535static u16 llc_exec_station_trans_actions(struct llc_station_state_trans *trans,
536 struct sk_buff *skb)
537{
538 u16 rc = 0;
539 llc_station_action_t *next_action = trans->ev_actions;
540
541 for (; next_action && *next_action; next_action++)
542 if ((*next_action)(skb))
543 rc = 1;
544 return rc;
545}
546
547/**
548 * llc_find_station_trans - finds transition for this event
549 * @skb: Address of the event
550 *
551 * Search thru events of the current state of the station until list
552 * exhausted or it's obvious that the event is not valid for the current
553 * state. Returns the address of the transition if cound, %NULL otherwise.
554 */
555static struct llc_station_state_trans *
556 llc_find_station_trans(struct sk_buff *skb)
557{
558 int i = 0;
559 struct llc_station_state_trans *rc = NULL;
560 struct llc_station_state_trans **next_trans;
561 struct llc_station_state *curr_state =
562 &llc_station_state_table[llc_main_station.state - 1];
563
564 for (next_trans = curr_state->transitions; next_trans[i]->ev; i++)
565 if (!next_trans[i]->ev(skb)) {
566 rc = next_trans[i];
567 break;
568 }
569 return rc;
570}
571
572/**
573 * llc_station_free_ev - frees an event
574 * @skb: Address of the event
575 *
576 * Frees an event.
577 */
578static void llc_station_free_ev(struct sk_buff *skb)
579{
580 struct llc_station_state_ev *ev = llc_station_ev(skb);
581
582 if (ev->type == LLC_STATION_EV_TYPE_PDU)
583 kfree_skb(skb);
584}
585
586/**
587 * llc_station_next_state - processes event and goes to the next state
588 * @skb: Address of the event
589 *
590 * Processes an event, executes any transitions related to that event and
591 * updates the state of the station.
592 */
593static u16 llc_station_next_state(struct sk_buff *skb)
594{
595 u16 rc = 1;
596 struct llc_station_state_trans *trans;
597
598 if (llc_main_station.state > LLC_NBR_STATION_STATES)
599 goto out;
600 trans = llc_find_station_trans(skb);
601 if (trans) {
602 /* got the state to which we next transition; perform the
603 * actions associated with this transition before actually
604 * transitioning to the next state
605 */
606 rc = llc_exec_station_trans_actions(trans, skb);
607 if (!rc)
608 /* transition station to next state if all actions
609 * execute successfully; done; wait for next event
610 */
611 llc_main_station.state = trans->next_state;
612 } else
613 /* event not recognized in current state; re-queue it for
614 * processing again at a later time; return failure
615 */
616 rc = 0;
617out:
618 llc_station_free_ev(skb);
619 return rc;
620}
621
622/**
623 * llc_station_service_events - service events in the queue
624 *
625 * Get an event from the station event queue (if any); attempt to service
626 * the event; if event serviced, get the next event (if any) on the event
627 * queue; if event not service, re-queue the event on the event queue and
628 * attempt to service the next event; when serviced all events in queue,
629 * finished; if don't transition to different state, just service all
630 * events once; if transition to new state, service all events again.
631 * Caller must hold llc_main_station.ev_q.lock.
632 */
633static void llc_station_service_events(void)
634{
635 struct sk_buff *skb;
636
637 while ((skb = skb_dequeue(&llc_main_station.ev_q.list)) != NULL)
638 llc_station_next_state(skb);
639}
640
641/**
642 * llc_station_state_process: queue event and try to process queue.
643 * @skb: Address of the event
644 *
645 * Queues an event (on the station event queue) for handling by the
646 * station state machine and attempts to process any queued-up events.
647 */
648static void llc_station_state_process(struct sk_buff *skb)
649{
650 spin_lock_bh(&llc_main_station.ev_q.lock);
651 skb_queue_tail(&llc_main_station.ev_q.list, skb);
652 llc_station_service_events();
653 spin_unlock_bh(&llc_main_station.ev_q.lock);
654}
655
656static void llc_station_ack_tmr_cb(unsigned long timeout_data)
657{
658 struct sk_buff *skb = alloc_skb(0, GFP_ATOMIC);
659
660 if (skb) {
661 struct llc_station_state_ev *ev = llc_station_ev(skb);
662
663 ev->type = LLC_STATION_EV_TYPE_ACK_TMR;
664 llc_station_state_process(skb);
665 }
666}
667
668/*
669 * llc_station_rcv - send received pdu to the station state machine
670 * @skb: received frame.
671 *
672 * Sends data unit to station state machine.
673 */
674static void llc_station_rcv(struct sk_buff *skb)
675{
676 struct llc_station_state_ev *ev = llc_station_ev(skb);
677
678 ev->type = LLC_STATION_EV_TYPE_PDU;
679 ev->reason = 0;
680 llc_station_state_process(skb);
681}
682
683int __init llc_station_init(void)
684{
685 u16 rc = -ENOBUFS;
686 struct sk_buff *skb;
687 struct llc_station_state_ev *ev;
688
689 skb_queue_head_init(&llc_main_station.mac_pdu_q);
690 skb_queue_head_init(&llc_main_station.ev_q.list);
691 spin_lock_init(&llc_main_station.ev_q.lock);
692 init_timer(&llc_main_station.ack_timer);
693 llc_main_station.ack_timer.data = (unsigned long)&llc_main_station;
694 llc_main_station.ack_timer.function = llc_station_ack_tmr_cb;
Arnaldo Carvalho de Melo590232a2005-09-22 04:30:44 -0300695 llc_main_station.ack_timer.expires = jiffies +
696 sysctl_llc_station_ack_timeout;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700697 skb = alloc_skb(0, GFP_ATOMIC);
698 if (!skb)
699 goto out;
700 rc = 0;
701 llc_set_station_handler(llc_station_rcv);
702 ev = llc_station_ev(skb);
703 memset(ev, 0, sizeof(*ev));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700704 llc_main_station.maximum_retry = 1;
705 llc_main_station.state = LLC_STATION_STATE_DOWN;
706 ev->type = LLC_STATION_EV_TYPE_SIMPLE;
707 ev->prim_type = LLC_STATION_EV_ENABLE_WITHOUT_DUP_ADDR_CHECK;
708 rc = llc_station_next_state(skb);
709out:
710 return rc;
711}
712
713void __exit llc_station_exit(void)
714{
715 llc_set_station_handler(NULL);
716}