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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 | */ | |
40 | struct 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 | ||
72 | struct 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 | ||
80 | static __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 | ||
86 | typedef 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 | ||
94 | typedef int (*llc_station_action_t)(struct sk_buff *skb); | |
95 | ||
96 | /* Station component state table structure */ | |
97 | struct llc_station_state_trans { | |
98 | llc_station_ev_t ev; | |
99 | u8 next_state; | |
100 | llc_station_action_t *ev_actions; | |
101 | }; | |
102 | ||
103 | struct llc_station_state { | |
104 | u8 curr_state; | |
105 | struct llc_station_state_trans **transitions; | |
106 | }; | |
107 | ||
108 | static struct llc_station llc_main_station; | |
109 | ||
110 | static 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 | ||
119 | static 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 | ||
128 | static 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 | ||
137 | static 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 | ||
146 | static 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 | ||
158 | static 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 | ||
171 | static 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 | ||
184 | static 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 | ||
196 | static 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 | */ | |
211 | static 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 | ||
219 | static 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 | ||
225 | static 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 | ||
231 | static 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 | ||
237 | static 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 | ||
243 | static 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 | ||
249 | static 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); | |
262 | out: | |
263 | return rc; | |
264 | free: | |
265 | kfree_skb(skb); | |
266 | goto out; | |
267 | } | |
268 | ||
269 | static 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); | |
287 | out: | |
288 | return rc; | |
289 | free: | |
290 | kfree_skb(skb); | |
291 | goto out; | |
292 | } | |
293 | ||
294 | static 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); | |
312 | out: | |
313 | return rc; | |
314 | free: | |
315 | kfree_skb(skb); | |
316 | goto out; | |
317 | } | |
318 | ||
319 | static 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 | */ | |
330 | static 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 */ | |
335 | static 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 | ||
343 | static 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 */ | |
350 | static llc_station_action_t llc_stat_down_state_actions_2[] = { | |
351 | [0] = llc_station_ac_report_status, /* STATION UP */ | |
352 | [1] = NULL, | |
353 | }; | |
354 | ||
355 | static 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 */ | |
362 | static 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 */ | |
370 | static llc_station_action_t llc_stat_up_state_actions_1[] = { | |
371 | [0] = llc_station_ac_report_status, /* STATION DOWN */ | |
372 | [1] = NULL, | |
373 | }; | |
374 | ||
375 | static 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 */ | |
382 | static llc_station_action_t llc_stat_up_state_actions_2[] = { | |
383 | [0] = llc_station_ac_send_xid_r, | |
384 | [1] = NULL, | |
385 | }; | |
386 | ||
387 | static 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 */ | |
394 | static llc_station_action_t llc_stat_up_state_actions_3[] = { | |
395 | [0] = llc_station_ac_send_test_r, | |
396 | [1] = NULL, | |
397 | }; | |
398 | ||
399 | static 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 */ | |
406 | static 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 | */ | |
417 | static 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 | ||
422 | static 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 | */ | |
431 | static 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 | ||
436 | static 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 */ | |
443 | static llc_station_action_t llc_stat_dupaddr_state_actions_3[] = { | |
444 | [0] = llc_station_ac_send_xid_r, | |
445 | [1] = NULL, | |
446 | }; | |
447 | ||
448 | static 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 | */ | |
457 | static 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 | ||
465 | static 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 | */ | |
474 | static llc_station_action_t llc_stat_dupaddr_state_actions_5[] = { | |
475 | [0] = llc_station_ac_report_status, /* STATION UP */ | |
476 | [1] = NULL, | |
477 | }; | |
478 | ||
479 | static 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 */ | |
486 | static llc_station_action_t llc_stat_dupaddr_state_actions_6[] = { | |
487 | [0] = llc_station_ac_report_status, /* STATION DOWN */ | |
488 | [1] = NULL, | |
489 | }; | |
490 | ||
491 | static 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 */ | |
498 | static 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 | ||
508 | static 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 | */ | |
532 | static 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 | */ | |
552 | static 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 | */ | |
575 | static 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 | */ | |
590 | static 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; | |
614 | out: | |
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 | */ | |
630 | static 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 | */ | |
645 | static 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 | ||
653 | static 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 | */ | |
671 | static 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 | ||
680 | int __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); | |
706 | out: | |
707 | return rc; | |
708 | } | |
709 | ||
710 | void __exit llc_station_exit(void) | |
711 | { | |
712 | llc_set_station_handler(NULL); | |
713 | } |