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