Root/
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/init.h> |
15 | #include <linux/module.h> |
16 | #include <linux/slab.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 | #define LLC_STATION_ACK_TIME (3 * HZ) |
54 | |
55 | int sysctl_llc_station_ack_timeout = LLC_STATION_ACK_TIME; |
56 | |
57 | /* 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 | |
76 | struct 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 | |
84 | static __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 | |
90 | typedef 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 | |
98 | typedef int (*llc_station_action_t)(struct sk_buff *skb); |
99 | |
100 | /* Station component state table structure */ |
101 | struct llc_station_state_trans { |
102 | llc_station_ev_t ev; |
103 | u8 next_state; |
104 | llc_station_action_t *ev_actions; |
105 | }; |
106 | |
107 | struct llc_station_state { |
108 | u8 curr_state; |
109 | struct llc_station_state_trans **transitions; |
110 | }; |
111 | |
112 | static struct llc_station llc_main_station; |
113 | |
114 | static 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 | |
123 | static 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 | |
132 | static 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 | |
141 | static 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 | |
150 | static 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 | |
162 | static 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 | |
175 | static 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 | |
188 | static 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 | |
200 | static 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 | */ |
215 | static 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 | |
223 | static int llc_station_ac_start_ack_timer(struct sk_buff *skb) |
224 | { |
225 | mod_timer(&llc_main_station.ack_timer, |
226 | jiffies + sysctl_llc_station_ack_timeout); |
227 | return 0; |
228 | } |
229 | |
230 | static 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 | |
236 | static 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 | |
242 | static 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 | |
248 | static 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 | |
254 | static int llc_station_ac_send_null_dsap_xid_c(struct sk_buff *skb) |
255 | { |
256 | int rc = 1; |
257 | struct sk_buff *nskb = llc_alloc_frame(NULL, skb->dev, LLC_PDU_TYPE_U, |
258 | sizeof(struct llc_xid_info)); |
259 | |
260 | if (!nskb) |
261 | goto out; |
262 | llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, 0, 0, LLC_PDU_CMD); |
263 | llc_pdu_init_as_xid_cmd(nskb, LLC_XID_NULL_CLASS_2, 127); |
264 | rc = llc_mac_hdr_init(nskb, skb->dev->dev_addr, skb->dev->dev_addr); |
265 | if (unlikely(rc)) |
266 | goto free; |
267 | llc_station_send_pdu(nskb); |
268 | out: |
269 | return rc; |
270 | free: |
271 | kfree_skb(skb); |
272 | goto out; |
273 | } |
274 | |
275 | static int llc_station_ac_send_xid_r(struct sk_buff *skb) |
276 | { |
277 | u8 mac_da[ETH_ALEN], dsap; |
278 | int rc = 1; |
279 | struct sk_buff *nskb = llc_alloc_frame(NULL, skb->dev, LLC_PDU_TYPE_U, |
280 | sizeof(struct llc_xid_info)); |
281 | |
282 | if (!nskb) |
283 | goto out; |
284 | rc = 0; |
285 | llc_pdu_decode_sa(skb, mac_da); |
286 | llc_pdu_decode_ssap(skb, &dsap); |
287 | llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, 0, dsap, LLC_PDU_RSP); |
288 | llc_pdu_init_as_xid_rsp(nskb, LLC_XID_NULL_CLASS_2, 127); |
289 | rc = llc_mac_hdr_init(nskb, skb->dev->dev_addr, mac_da); |
290 | if (unlikely(rc)) |
291 | goto free; |
292 | llc_station_send_pdu(nskb); |
293 | out: |
294 | return rc; |
295 | free: |
296 | kfree_skb(skb); |
297 | goto out; |
298 | } |
299 | |
300 | static int llc_station_ac_send_test_r(struct sk_buff *skb) |
301 | { |
302 | u8 mac_da[ETH_ALEN], dsap; |
303 | int rc = 1; |
304 | u32 data_size; |
305 | struct sk_buff *nskb; |
306 | |
307 | /* The test request command is type U (llc_len = 3) */ |
308 | data_size = ntohs(eth_hdr(skb)->h_proto) - 3; |
309 | nskb = llc_alloc_frame(NULL, skb->dev, LLC_PDU_TYPE_U, data_size); |
310 | |
311 | if (!nskb) |
312 | goto out; |
313 | rc = 0; |
314 | llc_pdu_decode_sa(skb, mac_da); |
315 | llc_pdu_decode_ssap(skb, &dsap); |
316 | llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, 0, dsap, LLC_PDU_RSP); |
317 | llc_pdu_init_as_test_rsp(nskb, skb); |
318 | rc = llc_mac_hdr_init(nskb, skb->dev->dev_addr, mac_da); |
319 | if (unlikely(rc)) |
320 | goto free; |
321 | llc_station_send_pdu(nskb); |
322 | out: |
323 | return rc; |
324 | free: |
325 | kfree_skb(skb); |
326 | goto out; |
327 | } |
328 | |
329 | static int llc_station_ac_report_status(struct sk_buff *skb) |
330 | { |
331 | return 0; |
332 | } |
333 | |
334 | /* COMMON STATION STATE transitions */ |
335 | |
336 | /* dummy last-transition indicator; common to all state transition groups |
337 | * last entry for this state |
338 | * all members are zeros, .bss zeroes it |
339 | */ |
340 | static struct llc_station_state_trans llc_stat_state_trans_end; |
341 | |
342 | /* DOWN STATE transitions */ |
343 | |
344 | /* state transition for LLC_STATION_EV_ENABLE_WITH_DUP_ADDR_CHECK event */ |
345 | static llc_station_action_t llc_stat_down_state_actions_1[] = { |
346 | [0] = llc_station_ac_start_ack_timer, |
347 | [1] = llc_station_ac_set_retry_cnt_0, |
348 | [2] = llc_station_ac_set_xid_r_cnt_0, |
349 | [3] = llc_station_ac_send_null_dsap_xid_c, |
350 | [4] = NULL, |
351 | }; |
352 | |
353 | static struct llc_station_state_trans llc_stat_down_state_trans_1 = { |
354 | .ev = llc_stat_ev_enable_with_dup_addr_check, |
355 | .next_state = LLC_STATION_STATE_DUP_ADDR_CHK, |
356 | .ev_actions = llc_stat_down_state_actions_1, |
357 | }; |
358 | |
359 | /* state transition for LLC_STATION_EV_ENABLE_WITHOUT_DUP_ADDR_CHECK event */ |
360 | static llc_station_action_t llc_stat_down_state_actions_2[] = { |
361 | [0] = llc_station_ac_report_status, /* STATION UP */ |
362 | [1] = NULL, |
363 | }; |
364 | |
365 | static struct llc_station_state_trans llc_stat_down_state_trans_2 = { |
366 | .ev = llc_stat_ev_enable_without_dup_addr_check, |
367 | .next_state = LLC_STATION_STATE_UP, |
368 | .ev_actions = llc_stat_down_state_actions_2, |
369 | }; |
370 | |
371 | /* array of pointers; one to each transition */ |
372 | static struct llc_station_state_trans *llc_stat_dwn_state_trans[] = { |
373 | [0] = &llc_stat_down_state_trans_1, |
374 | [1] = &llc_stat_down_state_trans_2, |
375 | [2] = &llc_stat_state_trans_end, |
376 | }; |
377 | |
378 | /* UP STATE transitions */ |
379 | /* state transition for LLC_STATION_EV_DISABLE_REQ event */ |
380 | static llc_station_action_t llc_stat_up_state_actions_1[] = { |
381 | [0] = llc_station_ac_report_status, /* STATION DOWN */ |
382 | [1] = NULL, |
383 | }; |
384 | |
385 | static struct llc_station_state_trans llc_stat_up_state_trans_1 = { |
386 | .ev = llc_stat_ev_disable_req, |
387 | .next_state = LLC_STATION_STATE_DOWN, |
388 | .ev_actions = llc_stat_up_state_actions_1, |
389 | }; |
390 | |
391 | /* state transition for LLC_STATION_EV_RX_NULL_DSAP_XID_C event */ |
392 | static llc_station_action_t llc_stat_up_state_actions_2[] = { |
393 | [0] = llc_station_ac_send_xid_r, |
394 | [1] = NULL, |
395 | }; |
396 | |
397 | static struct llc_station_state_trans llc_stat_up_state_trans_2 = { |
398 | .ev = llc_stat_ev_rx_null_dsap_xid_c, |
399 | .next_state = LLC_STATION_STATE_UP, |
400 | .ev_actions = llc_stat_up_state_actions_2, |
401 | }; |
402 | |
403 | /* state transition for LLC_STATION_EV_RX_NULL_DSAP_TEST_C event */ |
404 | static llc_station_action_t llc_stat_up_state_actions_3[] = { |
405 | [0] = llc_station_ac_send_test_r, |
406 | [1] = NULL, |
407 | }; |
408 | |
409 | static struct llc_station_state_trans llc_stat_up_state_trans_3 = { |
410 | .ev = llc_stat_ev_rx_null_dsap_test_c, |
411 | .next_state = LLC_STATION_STATE_UP, |
412 | .ev_actions = llc_stat_up_state_actions_3, |
413 | }; |
414 | |
415 | /* array of pointers; one to each transition */ |
416 | static struct llc_station_state_trans *llc_stat_up_state_trans [] = { |
417 | [0] = &llc_stat_up_state_trans_1, |
418 | [1] = &llc_stat_up_state_trans_2, |
419 | [2] = &llc_stat_up_state_trans_3, |
420 | [3] = &llc_stat_state_trans_end, |
421 | }; |
422 | |
423 | /* DUP ADDR CHK STATE transitions */ |
424 | /* state transition for LLC_STATION_EV_RX_NULL_DSAP_0_XID_R_XID_R_CNT_EQ |
425 | * event |
426 | */ |
427 | static llc_station_action_t llc_stat_dupaddr_state_actions_1[] = { |
428 | [0] = llc_station_ac_inc_xid_r_cnt_by_1, |
429 | [1] = NULL, |
430 | }; |
431 | |
432 | static struct llc_station_state_trans llc_stat_dupaddr_state_trans_1 = { |
433 | .ev = llc_stat_ev_rx_null_dsap_0_xid_r_xid_r_cnt_eq, |
434 | .next_state = LLC_STATION_STATE_DUP_ADDR_CHK, |
435 | .ev_actions = llc_stat_dupaddr_state_actions_1, |
436 | }; |
437 | |
438 | /* state transition for LLC_STATION_EV_RX_NULL_DSAP_1_XID_R_XID_R_CNT_EQ |
439 | * event |
440 | */ |
441 | static llc_station_action_t llc_stat_dupaddr_state_actions_2[] = { |
442 | [0] = llc_station_ac_report_status, /* DUPLICATE ADDRESS FOUND */ |
443 | [1] = NULL, |
444 | }; |
445 | |
446 | static struct llc_station_state_trans llc_stat_dupaddr_state_trans_2 = { |
447 | .ev = llc_stat_ev_rx_null_dsap_1_xid_r_xid_r_cnt_eq, |
448 | .next_state = LLC_STATION_STATE_DOWN, |
449 | .ev_actions = llc_stat_dupaddr_state_actions_2, |
450 | }; |
451 | |
452 | /* state transition for LLC_STATION_EV_RX_NULL_DSAP_XID_C event */ |
453 | static llc_station_action_t llc_stat_dupaddr_state_actions_3[] = { |
454 | [0] = llc_station_ac_send_xid_r, |
455 | [1] = NULL, |
456 | }; |
457 | |
458 | static struct llc_station_state_trans llc_stat_dupaddr_state_trans_3 = { |
459 | .ev = llc_stat_ev_rx_null_dsap_xid_c, |
460 | .next_state = LLC_STATION_STATE_DUP_ADDR_CHK, |
461 | .ev_actions = llc_stat_dupaddr_state_actions_3, |
462 | }; |
463 | |
464 | /* state transition for LLC_STATION_EV_ACK_TMR_EXP_LT_RETRY_CNT_MAX_RETRY |
465 | * event |
466 | */ |
467 | static llc_station_action_t llc_stat_dupaddr_state_actions_4[] = { |
468 | [0] = llc_station_ac_start_ack_timer, |
469 | [1] = llc_station_ac_inc_retry_cnt_by_1, |
470 | [2] = llc_station_ac_set_xid_r_cnt_0, |
471 | [3] = llc_station_ac_send_null_dsap_xid_c, |
472 | [4] = NULL, |
473 | }; |
474 | |
475 | static struct llc_station_state_trans llc_stat_dupaddr_state_trans_4 = { |
476 | .ev = llc_stat_ev_ack_tmr_exp_lt_retry_cnt_max_retry, |
477 | .next_state = LLC_STATION_STATE_DUP_ADDR_CHK, |
478 | .ev_actions = llc_stat_dupaddr_state_actions_4, |
479 | }; |
480 | |
481 | /* state transition for LLC_STATION_EV_ACK_TMR_EXP_EQ_RETRY_CNT_MAX_RETRY |
482 | * event |
483 | */ |
484 | static llc_station_action_t llc_stat_dupaddr_state_actions_5[] = { |
485 | [0] = llc_station_ac_report_status, /* STATION UP */ |
486 | [1] = NULL, |
487 | }; |
488 | |
489 | static struct llc_station_state_trans llc_stat_dupaddr_state_trans_5 = { |
490 | .ev = llc_stat_ev_ack_tmr_exp_eq_retry_cnt_max_retry, |
491 | .next_state = LLC_STATION_STATE_UP, |
492 | .ev_actions = llc_stat_dupaddr_state_actions_5, |
493 | }; |
494 | |
495 | /* state transition for LLC_STATION_EV_DISABLE_REQ event */ |
496 | static llc_station_action_t llc_stat_dupaddr_state_actions_6[] = { |
497 | [0] = llc_station_ac_report_status, /* STATION DOWN */ |
498 | [1] = NULL, |
499 | }; |
500 | |
501 | static struct llc_station_state_trans llc_stat_dupaddr_state_trans_6 = { |
502 | .ev = llc_stat_ev_disable_req, |
503 | .next_state = LLC_STATION_STATE_DOWN, |
504 | .ev_actions = llc_stat_dupaddr_state_actions_6, |
505 | }; |
506 | |
507 | /* array of pointers; one to each transition */ |
508 | static struct llc_station_state_trans *llc_stat_dupaddr_state_trans[] = { |
509 | [0] = &llc_stat_dupaddr_state_trans_6, /* Request */ |
510 | [1] = &llc_stat_dupaddr_state_trans_4, /* Timer */ |
511 | [2] = &llc_stat_dupaddr_state_trans_5, |
512 | [3] = &llc_stat_dupaddr_state_trans_1, /* Receive frame */ |
513 | [4] = &llc_stat_dupaddr_state_trans_2, |
514 | [5] = &llc_stat_dupaddr_state_trans_3, |
515 | [6] = &llc_stat_state_trans_end, |
516 | }; |
517 | |
518 | static struct llc_station_state |
519 | llc_station_state_table[LLC_NBR_STATION_STATES] = { |
520 | [LLC_STATION_STATE_DOWN - 1] = { |
521 | .curr_state = LLC_STATION_STATE_DOWN, |
522 | .transitions = llc_stat_dwn_state_trans, |
523 | }, |
524 | [LLC_STATION_STATE_DUP_ADDR_CHK - 1] = { |
525 | .curr_state = LLC_STATION_STATE_DUP_ADDR_CHK, |
526 | .transitions = llc_stat_dupaddr_state_trans, |
527 | }, |
528 | [LLC_STATION_STATE_UP - 1] = { |
529 | .curr_state = LLC_STATION_STATE_UP, |
530 | .transitions = llc_stat_up_state_trans, |
531 | }, |
532 | }; |
533 | |
534 | /** |
535 | * llc_exec_station_trans_actions - executes actions for transition |
536 | * @trans: Address of the transition |
537 | * @skb: Address of the event that caused the transition |
538 | * |
539 | * Executes actions of a transition of the station state machine. Returns |
540 | * 0 if all actions complete successfully, nonzero otherwise. |
541 | */ |
542 | static u16 llc_exec_station_trans_actions(struct llc_station_state_trans *trans, |
543 | struct sk_buff *skb) |
544 | { |
545 | u16 rc = 0; |
546 | llc_station_action_t *next_action = trans->ev_actions; |
547 | |
548 | for (; next_action && *next_action; next_action++) |
549 | if ((*next_action)(skb)) |
550 | rc = 1; |
551 | return rc; |
552 | } |
553 | |
554 | /** |
555 | * llc_find_station_trans - finds transition for this event |
556 | * @skb: Address of the event |
557 | * |
558 | * Search thru events of the current state of the station until list |
559 | * exhausted or it's obvious that the event is not valid for the current |
560 | * state. Returns the address of the transition if cound, %NULL otherwise. |
561 | */ |
562 | static struct llc_station_state_trans * |
563 | llc_find_station_trans(struct sk_buff *skb) |
564 | { |
565 | int i = 0; |
566 | struct llc_station_state_trans *rc = NULL; |
567 | struct llc_station_state_trans **next_trans; |
568 | struct llc_station_state *curr_state = |
569 | &llc_station_state_table[llc_main_station.state - 1]; |
570 | |
571 | for (next_trans = curr_state->transitions; next_trans[i]->ev; i++) |
572 | if (!next_trans[i]->ev(skb)) { |
573 | rc = next_trans[i]; |
574 | break; |
575 | } |
576 | return rc; |
577 | } |
578 | |
579 | /** |
580 | * llc_station_free_ev - frees an event |
581 | * @skb: Address of the event |
582 | * |
583 | * Frees an event. |
584 | */ |
585 | static void llc_station_free_ev(struct sk_buff *skb) |
586 | { |
587 | struct llc_station_state_ev *ev = llc_station_ev(skb); |
588 | |
589 | if (ev->type == LLC_STATION_EV_TYPE_PDU) |
590 | kfree_skb(skb); |
591 | } |
592 | |
593 | /** |
594 | * llc_station_next_state - processes event and goes to the next state |
595 | * @skb: Address of the event |
596 | * |
597 | * Processes an event, executes any transitions related to that event and |
598 | * updates the state of the station. |
599 | */ |
600 | static u16 llc_station_next_state(struct sk_buff *skb) |
601 | { |
602 | u16 rc = 1; |
603 | struct llc_station_state_trans *trans; |
604 | |
605 | if (llc_main_station.state > LLC_NBR_STATION_STATES) |
606 | goto out; |
607 | trans = llc_find_station_trans(skb); |
608 | if (trans) { |
609 | /* got the state to which we next transition; perform the |
610 | * actions associated with this transition before actually |
611 | * transitioning to the next state |
612 | */ |
613 | rc = llc_exec_station_trans_actions(trans, skb); |
614 | if (!rc) |
615 | /* transition station to next state if all actions |
616 | * execute successfully; done; wait for next event |
617 | */ |
618 | llc_main_station.state = trans->next_state; |
619 | } else |
620 | /* event not recognized in current state; re-queue it for |
621 | * processing again at a later time; return failure |
622 | */ |
623 | rc = 0; |
624 | out: |
625 | llc_station_free_ev(skb); |
626 | return rc; |
627 | } |
628 | |
629 | /** |
630 | * llc_station_service_events - service events in the queue |
631 | * |
632 | * Get an event from the station event queue (if any); attempt to service |
633 | * the event; if event serviced, get the next event (if any) on the event |
634 | * queue; if event not service, re-queue the event on the event queue and |
635 | * attempt to service the next event; when serviced all events in queue, |
636 | * finished; if don't transition to different state, just service all |
637 | * events once; if transition to new state, service all events again. |
638 | * Caller must hold llc_main_station.ev_q.lock. |
639 | */ |
640 | static void llc_station_service_events(void) |
641 | { |
642 | struct sk_buff *skb; |
643 | |
644 | while ((skb = skb_dequeue(&llc_main_station.ev_q.list)) != NULL) |
645 | llc_station_next_state(skb); |
646 | } |
647 | |
648 | /** |
649 | * llc_station_state_process: queue event and try to process queue. |
650 | * @skb: Address of the event |
651 | * |
652 | * Queues an event (on the station event queue) for handling by the |
653 | * station state machine and attempts to process any queued-up events. |
654 | */ |
655 | static void llc_station_state_process(struct sk_buff *skb) |
656 | { |
657 | spin_lock_bh(&llc_main_station.ev_q.lock); |
658 | skb_queue_tail(&llc_main_station.ev_q.list, skb); |
659 | llc_station_service_events(); |
660 | spin_unlock_bh(&llc_main_station.ev_q.lock); |
661 | } |
662 | |
663 | static void llc_station_ack_tmr_cb(unsigned long timeout_data) |
664 | { |
665 | struct sk_buff *skb = alloc_skb(0, GFP_ATOMIC); |
666 | |
667 | if (skb) { |
668 | struct llc_station_state_ev *ev = llc_station_ev(skb); |
669 | |
670 | ev->type = LLC_STATION_EV_TYPE_ACK_TMR; |
671 | llc_station_state_process(skb); |
672 | } |
673 | } |
674 | |
675 | /* |
676 | * llc_station_rcv - send received pdu to the station state machine |
677 | * @skb: received frame. |
678 | * |
679 | * Sends data unit to station state machine. |
680 | */ |
681 | static void llc_station_rcv(struct sk_buff *skb) |
682 | { |
683 | struct llc_station_state_ev *ev = llc_station_ev(skb); |
684 | |
685 | ev->type = LLC_STATION_EV_TYPE_PDU; |
686 | ev->reason = 0; |
687 | llc_station_state_process(skb); |
688 | } |
689 | |
690 | int __init llc_station_init(void) |
691 | { |
692 | u16 rc = -ENOBUFS; |
693 | struct sk_buff *skb; |
694 | struct llc_station_state_ev *ev; |
695 | |
696 | skb_queue_head_init(&llc_main_station.mac_pdu_q); |
697 | skb_queue_head_init(&llc_main_station.ev_q.list); |
698 | spin_lock_init(&llc_main_station.ev_q.lock); |
699 | setup_timer(&llc_main_station.ack_timer, llc_station_ack_tmr_cb, |
700 | (unsigned long)&llc_main_station); |
701 | llc_main_station.ack_timer.expires = jiffies + |
702 | sysctl_llc_station_ack_timeout; |
703 | skb = alloc_skb(0, GFP_ATOMIC); |
704 | if (!skb) |
705 | goto out; |
706 | rc = 0; |
707 | llc_set_station_handler(llc_station_rcv); |
708 | ev = llc_station_ev(skb); |
709 | memset(ev, 0, sizeof(*ev)); |
710 | llc_main_station.maximum_retry = 1; |
711 | llc_main_station.state = LLC_STATION_STATE_DOWN; |
712 | ev->type = LLC_STATION_EV_TYPE_SIMPLE; |
713 | ev->prim_type = LLC_STATION_EV_ENABLE_WITHOUT_DUP_ADDR_CHECK; |
714 | rc = llc_station_next_state(skb); |
715 | out: |
716 | return rc; |
717 | } |
718 | |
719 | void __exit llc_station_exit(void) |
720 | { |
721 | llc_set_station_handler(NULL); |
722 | } |
723 |
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