1 /* 2 * llc_conn.c - Driver routines for connection component. 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 15 #include <linux/init.h> 16 #include <linux/slab.h> 17 #include <net/llc.h> 18 #include <net/llc_c_ac.h> 19 #include <net/llc_c_ev.h> 20 #include <net/llc_c_st.h> 21 #include <net/llc_conn.h> 22 #include <net/llc_pdu.h> 23 #include <net/llc_sap.h> 24 #include <net/sock.h> 25 #include <net/tcp_states.h> 26 27 #if 0 28 #define dprintk(args...) printk(KERN_DEBUG args) 29 #else 30 #define dprintk(args...) 31 #endif 32 33 static int llc_find_offset(int state, int ev_type); 34 static void llc_conn_send_pdus(struct sock *sk); 35 static int llc_conn_service(struct sock *sk, struct sk_buff *skb); 36 static int llc_exec_conn_trans_actions(struct sock *sk, 37 const struct llc_conn_state_trans *trans, 38 struct sk_buff *ev); 39 static const struct llc_conn_state_trans *llc_qualify_conn_ev(struct sock *sk, 40 struct sk_buff *skb); 41 42 /* Offset table on connection states transition diagram */ 43 static int llc_offset_table[NBR_CONN_STATES][NBR_CONN_EV]; 44 45 int sysctl_llc2_ack_timeout = LLC2_ACK_TIME * HZ; 46 int sysctl_llc2_p_timeout = LLC2_P_TIME * HZ; 47 int sysctl_llc2_rej_timeout = LLC2_REJ_TIME * HZ; 48 int sysctl_llc2_busy_timeout = LLC2_BUSY_TIME * HZ; 49 50 /** 51 * llc_conn_state_process - sends event to connection state machine 52 * @sk: connection 53 * @skb: occurred event 54 * 55 * Sends an event to connection state machine. After processing event 56 * (executing it's actions and changing state), upper layer will be 57 * indicated or confirmed, if needed. Returns 0 for success, 1 for 58 * failure. The socket lock has to be held before calling this function. 59 * 60 * This function always consumes a reference to the skb. 61 */ 62 int llc_conn_state_process(struct sock *sk, struct sk_buff *skb) 63 { 64 int rc; 65 struct llc_sock *llc = llc_sk(skb->sk); 66 struct llc_conn_state_ev *ev = llc_conn_ev(skb); 67 68 ev->ind_prim = ev->cfm_prim = 0; 69 /* 70 * Send event to state machine 71 */ 72 rc = llc_conn_service(skb->sk, skb); 73 if (unlikely(rc != 0)) { 74 printk(KERN_ERR "%s: llc_conn_service failed\n", __func__); 75 goto out_skb_put; 76 } 77 78 switch (ev->ind_prim) { 79 case LLC_DATA_PRIM: 80 skb_get(skb); 81 llc_save_primitive(sk, skb, LLC_DATA_PRIM); 82 if (unlikely(sock_queue_rcv_skb(sk, skb))) { 83 /* 84 * shouldn't happen 85 */ 86 printk(KERN_ERR "%s: sock_queue_rcv_skb failed!\n", 87 __func__); 88 kfree_skb(skb); 89 } 90 break; 91 case LLC_CONN_PRIM: 92 /* 93 * Can't be sock_queue_rcv_skb, because we have to leave the 94 * skb->sk pointing to the newly created struct sock in 95 * llc_conn_handler. -acme 96 */ 97 skb_get(skb); 98 skb_queue_tail(&sk->sk_receive_queue, skb); 99 sk->sk_state_change(sk); 100 break; 101 case LLC_DISC_PRIM: 102 sock_hold(sk); 103 if (sk->sk_type == SOCK_STREAM && 104 sk->sk_state == TCP_ESTABLISHED) { 105 sk->sk_shutdown = SHUTDOWN_MASK; 106 sk->sk_socket->state = SS_UNCONNECTED; 107 sk->sk_state = TCP_CLOSE; 108 if (!sock_flag(sk, SOCK_DEAD)) { 109 sock_set_flag(sk, SOCK_DEAD); 110 sk->sk_state_change(sk); 111 } 112 } 113 sock_put(sk); 114 break; 115 case LLC_RESET_PRIM: 116 /* 117 * FIXME: 118 * RESET is not being notified to upper layers for now 119 */ 120 printk(KERN_INFO "%s: received a reset ind!\n", __func__); 121 break; 122 default: 123 if (ev->ind_prim) 124 printk(KERN_INFO "%s: received unknown %d prim!\n", 125 __func__, ev->ind_prim); 126 /* No indication */ 127 break; 128 } 129 130 switch (ev->cfm_prim) { 131 case LLC_DATA_PRIM: 132 if (!llc_data_accept_state(llc->state)) 133 sk->sk_write_space(sk); 134 else 135 rc = llc->failed_data_req = 1; 136 break; 137 case LLC_CONN_PRIM: 138 if (sk->sk_type == SOCK_STREAM && 139 sk->sk_state == TCP_SYN_SENT) { 140 if (ev->status) { 141 sk->sk_socket->state = SS_UNCONNECTED; 142 sk->sk_state = TCP_CLOSE; 143 } else { 144 sk->sk_socket->state = SS_CONNECTED; 145 sk->sk_state = TCP_ESTABLISHED; 146 } 147 sk->sk_state_change(sk); 148 } 149 break; 150 case LLC_DISC_PRIM: 151 sock_hold(sk); 152 if (sk->sk_type == SOCK_STREAM && sk->sk_state == TCP_CLOSING) { 153 sk->sk_socket->state = SS_UNCONNECTED; 154 sk->sk_state = TCP_CLOSE; 155 sk->sk_state_change(sk); 156 } 157 sock_put(sk); 158 break; 159 case LLC_RESET_PRIM: 160 /* 161 * FIXME: 162 * RESET is not being notified to upper layers for now 163 */ 164 printk(KERN_INFO "%s: received a reset conf!\n", __func__); 165 break; 166 default: 167 if (ev->cfm_prim) 168 printk(KERN_INFO "%s: received unknown %d prim!\n", 169 __func__, ev->cfm_prim); 170 /* No confirmation */ 171 break; 172 } 173 out_skb_put: 174 kfree_skb(skb); 175 return rc; 176 } 177 178 void llc_conn_send_pdu(struct sock *sk, struct sk_buff *skb) 179 { 180 /* queue PDU to send to MAC layer */ 181 skb_queue_tail(&sk->sk_write_queue, skb); 182 llc_conn_send_pdus(sk); 183 } 184 185 /** 186 * llc_conn_rtn_pdu - sends received data pdu to upper layer 187 * @sk: Active connection 188 * @skb: Received data frame 189 * 190 * Sends received data pdu to upper layer (by using indicate function). 191 * Prepares service parameters (prim and prim_data). calling indication 192 * function will be done in llc_conn_state_process. 193 */ 194 void llc_conn_rtn_pdu(struct sock *sk, struct sk_buff *skb) 195 { 196 struct llc_conn_state_ev *ev = llc_conn_ev(skb); 197 198 ev->ind_prim = LLC_DATA_PRIM; 199 } 200 201 /** 202 * llc_conn_resend_i_pdu_as_cmd - resend all all unacknowledged I PDUs 203 * @sk: active connection 204 * @nr: NR 205 * @first_p_bit: p_bit value of first pdu 206 * 207 * Resend all unacknowledged I PDUs, starting with the NR; send first as 208 * command PDU with P bit equal first_p_bit; if more than one send 209 * subsequent as command PDUs with P bit equal zero (0). 210 */ 211 void llc_conn_resend_i_pdu_as_cmd(struct sock *sk, u8 nr, u8 first_p_bit) 212 { 213 struct sk_buff *skb; 214 struct llc_pdu_sn *pdu; 215 u16 nbr_unack_pdus; 216 struct llc_sock *llc; 217 u8 howmany_resend = 0; 218 219 llc_conn_remove_acked_pdus(sk, nr, &nbr_unack_pdus); 220 if (!nbr_unack_pdus) 221 goto out; 222 /* 223 * Process unack PDUs only if unack queue is not empty; remove 224 * appropriate PDUs, fix them up, and put them on mac_pdu_q. 225 */ 226 llc = llc_sk(sk); 227 228 while ((skb = skb_dequeue(&llc->pdu_unack_q)) != NULL) { 229 pdu = llc_pdu_sn_hdr(skb); 230 llc_pdu_set_cmd_rsp(skb, LLC_PDU_CMD); 231 llc_pdu_set_pf_bit(skb, first_p_bit); 232 skb_queue_tail(&sk->sk_write_queue, skb); 233 first_p_bit = 0; 234 llc->vS = LLC_I_GET_NS(pdu); 235 howmany_resend++; 236 } 237 if (howmany_resend > 0) 238 llc->vS = (llc->vS + 1) % LLC_2_SEQ_NBR_MODULO; 239 /* any PDUs to re-send are queued up; start sending to MAC */ 240 llc_conn_send_pdus(sk); 241 out:; 242 } 243 244 /** 245 * llc_conn_resend_i_pdu_as_rsp - Resend all unacknowledged I PDUs 246 * @sk: active connection. 247 * @nr: NR 248 * @first_f_bit: f_bit value of first pdu. 249 * 250 * Resend all unacknowledged I PDUs, starting with the NR; send first as 251 * response PDU with F bit equal first_f_bit; if more than one send 252 * subsequent as response PDUs with F bit equal zero (0). 253 */ 254 void llc_conn_resend_i_pdu_as_rsp(struct sock *sk, u8 nr, u8 first_f_bit) 255 { 256 struct sk_buff *skb; 257 u16 nbr_unack_pdus; 258 struct llc_sock *llc = llc_sk(sk); 259 u8 howmany_resend = 0; 260 261 llc_conn_remove_acked_pdus(sk, nr, &nbr_unack_pdus); 262 if (!nbr_unack_pdus) 263 goto out; 264 /* 265 * Process unack PDUs only if unack queue is not empty; remove 266 * appropriate PDUs, fix them up, and put them on mac_pdu_q 267 */ 268 while ((skb = skb_dequeue(&llc->pdu_unack_q)) != NULL) { 269 struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb); 270 271 llc_pdu_set_cmd_rsp(skb, LLC_PDU_RSP); 272 llc_pdu_set_pf_bit(skb, first_f_bit); 273 skb_queue_tail(&sk->sk_write_queue, skb); 274 first_f_bit = 0; 275 llc->vS = LLC_I_GET_NS(pdu); 276 howmany_resend++; 277 } 278 if (howmany_resend > 0) 279 llc->vS = (llc->vS + 1) % LLC_2_SEQ_NBR_MODULO; 280 /* any PDUs to re-send are queued up; start sending to MAC */ 281 llc_conn_send_pdus(sk); 282 out:; 283 } 284 285 /** 286 * llc_conn_remove_acked_pdus - Removes acknowledged pdus from tx queue 287 * @sk: active connection 288 * @nr: NR 289 * @how_many_unacked: size of pdu_unack_q after removing acked pdus 290 * 291 * Removes acknowledged pdus from transmit queue (pdu_unack_q). Returns 292 * the number of pdus that removed from queue. 293 */ 294 int llc_conn_remove_acked_pdus(struct sock *sk, u8 nr, u16 *how_many_unacked) 295 { 296 int pdu_pos, i; 297 struct sk_buff *skb; 298 struct llc_pdu_sn *pdu; 299 int nbr_acked = 0; 300 struct llc_sock *llc = llc_sk(sk); 301 int q_len = skb_queue_len(&llc->pdu_unack_q); 302 303 if (!q_len) 304 goto out; 305 skb = skb_peek(&llc->pdu_unack_q); 306 pdu = llc_pdu_sn_hdr(skb); 307 308 /* finding position of last acked pdu in queue */ 309 pdu_pos = ((int)LLC_2_SEQ_NBR_MODULO + (int)nr - 310 (int)LLC_I_GET_NS(pdu)) % LLC_2_SEQ_NBR_MODULO; 311 312 for (i = 0; i < pdu_pos && i < q_len; i++) { 313 skb = skb_dequeue(&llc->pdu_unack_q); 314 kfree_skb(skb); 315 nbr_acked++; 316 } 317 out: 318 *how_many_unacked = skb_queue_len(&llc->pdu_unack_q); 319 return nbr_acked; 320 } 321 322 /** 323 * llc_conn_send_pdus - Sends queued PDUs 324 * @sk: active connection 325 * 326 * Sends queued pdus to MAC layer for transmission. 327 */ 328 static void llc_conn_send_pdus(struct sock *sk) 329 { 330 struct sk_buff *skb; 331 332 while ((skb = skb_dequeue(&sk->sk_write_queue)) != NULL) { 333 struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb); 334 335 if (LLC_PDU_TYPE_IS_I(pdu) && 336 !(skb->dev->flags & IFF_LOOPBACK)) { 337 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC); 338 339 skb_queue_tail(&llc_sk(sk)->pdu_unack_q, skb); 340 if (!skb2) 341 break; 342 skb = skb2; 343 } 344 dev_queue_xmit(skb); 345 } 346 } 347 348 /** 349 * llc_conn_service - finds transition and changes state of connection 350 * @sk: connection 351 * @skb: happened event 352 * 353 * This function finds transition that matches with happened event, then 354 * executes related actions and finally changes state of connection. 355 * Returns 0 for success, 1 for failure. 356 */ 357 static int llc_conn_service(struct sock *sk, struct sk_buff *skb) 358 { 359 const struct llc_conn_state_trans *trans; 360 struct llc_sock *llc = llc_sk(sk); 361 int rc = 1; 362 363 if (llc->state > NBR_CONN_STATES) 364 goto out; 365 rc = 0; 366 trans = llc_qualify_conn_ev(sk, skb); 367 if (trans) { 368 rc = llc_exec_conn_trans_actions(sk, trans, skb); 369 if (!rc && trans->next_state != NO_STATE_CHANGE) { 370 llc->state = trans->next_state; 371 if (!llc_data_accept_state(llc->state)) 372 sk->sk_state_change(sk); 373 } 374 } 375 out: 376 return rc; 377 } 378 379 /** 380 * llc_qualify_conn_ev - finds transition for event 381 * @sk: connection 382 * @skb: happened event 383 * 384 * This function finds transition that matches with happened event. 385 * Returns pointer to found transition on success, %NULL otherwise. 386 */ 387 static const struct llc_conn_state_trans *llc_qualify_conn_ev(struct sock *sk, 388 struct sk_buff *skb) 389 { 390 const struct llc_conn_state_trans **next_trans; 391 const llc_conn_ev_qfyr_t *next_qualifier; 392 struct llc_conn_state_ev *ev = llc_conn_ev(skb); 393 struct llc_sock *llc = llc_sk(sk); 394 struct llc_conn_state *curr_state = 395 &llc_conn_state_table[llc->state - 1]; 396 397 /* search thru events for this state until 398 * list exhausted or until no more 399 */ 400 for (next_trans = curr_state->transitions + 401 llc_find_offset(llc->state - 1, ev->type); 402 (*next_trans)->ev; next_trans++) { 403 if (!((*next_trans)->ev)(sk, skb)) { 404 /* got POSSIBLE event match; the event may require 405 * qualification based on the values of a number of 406 * state flags; if all qualifications are met (i.e., 407 * if all qualifying functions return success, or 0, 408 * then this is THE event we're looking for 409 */ 410 for (next_qualifier = (*next_trans)->ev_qualifiers; 411 next_qualifier && *next_qualifier && 412 !(*next_qualifier)(sk, skb); next_qualifier++) 413 /* nothing */; 414 if (!next_qualifier || !*next_qualifier) 415 /* all qualifiers executed successfully; this is 416 * our transition; return it so we can perform 417 * the associated actions & change the state 418 */ 419 return *next_trans; 420 } 421 } 422 return NULL; 423 } 424 425 /** 426 * llc_exec_conn_trans_actions - executes related actions 427 * @sk: connection 428 * @trans: transition that it's actions must be performed 429 * @skb: event 430 * 431 * Executes actions that is related to happened event. Returns 0 for 432 * success, 1 to indicate failure of at least one action. 433 */ 434 static int llc_exec_conn_trans_actions(struct sock *sk, 435 const struct llc_conn_state_trans *trans, 436 struct sk_buff *skb) 437 { 438 int rc = 0; 439 const llc_conn_action_t *next_action; 440 441 for (next_action = trans->ev_actions; 442 next_action && *next_action; next_action++) { 443 int rc2 = (*next_action)(sk, skb); 444 445 if (rc2 == 2) { 446 rc = rc2; 447 break; 448 } else if (rc2) 449 rc = 1; 450 } 451 return rc; 452 } 453 454 static inline bool llc_estab_match(const struct llc_sap *sap, 455 const struct llc_addr *daddr, 456 const struct llc_addr *laddr, 457 const struct sock *sk, 458 const struct net *net) 459 { 460 struct llc_sock *llc = llc_sk(sk); 461 462 return net_eq(sock_net(sk), net) && 463 llc->laddr.lsap == laddr->lsap && 464 llc->daddr.lsap == daddr->lsap && 465 ether_addr_equal(llc->laddr.mac, laddr->mac) && 466 ether_addr_equal(llc->daddr.mac, daddr->mac); 467 } 468 469 /** 470 * __llc_lookup_established - Finds connection for the remote/local sap/mac 471 * @sap: SAP 472 * @daddr: address of remote LLC (MAC + SAP) 473 * @laddr: address of local LLC (MAC + SAP) 474 * @net: netns to look up a socket in 475 * 476 * Search connection list of the SAP and finds connection using the remote 477 * mac, remote sap, local mac, and local sap. Returns pointer for 478 * connection found, %NULL otherwise. 479 * Caller has to make sure local_bh is disabled. 480 */ 481 static struct sock *__llc_lookup_established(struct llc_sap *sap, 482 struct llc_addr *daddr, 483 struct llc_addr *laddr, 484 const struct net *net) 485 { 486 struct sock *rc; 487 struct hlist_nulls_node *node; 488 int slot = llc_sk_laddr_hashfn(sap, laddr); 489 struct hlist_nulls_head *laddr_hb = &sap->sk_laddr_hash[slot]; 490 491 rcu_read_lock(); 492 again: 493 sk_nulls_for_each_rcu(rc, node, laddr_hb) { 494 if (llc_estab_match(sap, daddr, laddr, rc, net)) { 495 /* Extra checks required by SLAB_TYPESAFE_BY_RCU */ 496 if (unlikely(!refcount_inc_not_zero(&rc->sk_refcnt))) 497 goto again; 498 if (unlikely(llc_sk(rc)->sap != sap || 499 !llc_estab_match(sap, daddr, laddr, rc, net))) { 500 sock_put(rc); 501 continue; 502 } 503 goto found; 504 } 505 } 506 rc = NULL; 507 /* 508 * if the nulls value we got at the end of this lookup is 509 * not the expected one, we must restart lookup. 510 * We probably met an item that was moved to another chain. 511 */ 512 if (unlikely(get_nulls_value(node) != slot)) 513 goto again; 514 found: 515 rcu_read_unlock(); 516 return rc; 517 } 518 519 struct sock *llc_lookup_established(struct llc_sap *sap, 520 struct llc_addr *daddr, 521 struct llc_addr *laddr, 522 const struct net *net) 523 { 524 struct sock *sk; 525 526 local_bh_disable(); 527 sk = __llc_lookup_established(sap, daddr, laddr, net); 528 local_bh_enable(); 529 return sk; 530 } 531 532 static inline bool llc_listener_match(const struct llc_sap *sap, 533 const struct llc_addr *laddr, 534 const struct sock *sk, 535 const struct net *net) 536 { 537 struct llc_sock *llc = llc_sk(sk); 538 539 return net_eq(sock_net(sk), net) && 540 sk->sk_type == SOCK_STREAM && sk->sk_state == TCP_LISTEN && 541 llc->laddr.lsap == laddr->lsap && 542 ether_addr_equal(llc->laddr.mac, laddr->mac); 543 } 544 545 static struct sock *__llc_lookup_listener(struct llc_sap *sap, 546 struct llc_addr *laddr, 547 const struct net *net) 548 { 549 struct sock *rc; 550 struct hlist_nulls_node *node; 551 int slot = llc_sk_laddr_hashfn(sap, laddr); 552 struct hlist_nulls_head *laddr_hb = &sap->sk_laddr_hash[slot]; 553 554 rcu_read_lock(); 555 again: 556 sk_nulls_for_each_rcu(rc, node, laddr_hb) { 557 if (llc_listener_match(sap, laddr, rc, net)) { 558 /* Extra checks required by SLAB_TYPESAFE_BY_RCU */ 559 if (unlikely(!refcount_inc_not_zero(&rc->sk_refcnt))) 560 goto again; 561 if (unlikely(llc_sk(rc)->sap != sap || 562 !llc_listener_match(sap, laddr, rc, net))) { 563 sock_put(rc); 564 continue; 565 } 566 goto found; 567 } 568 } 569 rc = NULL; 570 /* 571 * if the nulls value we got at the end of this lookup is 572 * not the expected one, we must restart lookup. 573 * We probably met an item that was moved to another chain. 574 */ 575 if (unlikely(get_nulls_value(node) != slot)) 576 goto again; 577 found: 578 rcu_read_unlock(); 579 return rc; 580 } 581 582 /** 583 * llc_lookup_listener - Finds listener for local MAC + SAP 584 * @sap: SAP 585 * @laddr: address of local LLC (MAC + SAP) 586 * @net: netns to look up a socket in 587 * 588 * Search connection list of the SAP and finds connection listening on 589 * local mac, and local sap. Returns pointer for parent socket found, 590 * %NULL otherwise. 591 * Caller has to make sure local_bh is disabled. 592 */ 593 static struct sock *llc_lookup_listener(struct llc_sap *sap, 594 struct llc_addr *laddr, 595 const struct net *net) 596 { 597 struct sock *rc = __llc_lookup_listener(sap, laddr, net); 598 static struct llc_addr null_addr; 599 600 if (!rc) 601 rc = __llc_lookup_listener(sap, &null_addr, net); 602 603 return rc; 604 } 605 606 static struct sock *__llc_lookup(struct llc_sap *sap, 607 struct llc_addr *daddr, 608 struct llc_addr *laddr, 609 const struct net *net) 610 { 611 struct sock *sk = __llc_lookup_established(sap, daddr, laddr, net); 612 613 return sk ? : llc_lookup_listener(sap, laddr, net); 614 } 615 616 /** 617 * llc_data_accept_state - designates if in this state data can be sent. 618 * @state: state of connection. 619 * 620 * Returns 0 if data can be sent, 1 otherwise. 621 */ 622 u8 llc_data_accept_state(u8 state) 623 { 624 return state != LLC_CONN_STATE_NORMAL && state != LLC_CONN_STATE_BUSY && 625 state != LLC_CONN_STATE_REJ; 626 } 627 628 /** 629 * llc_find_next_offset - finds offset for next category of transitions 630 * @state: state table. 631 * @offset: start offset. 632 * 633 * Finds offset of next category of transitions in transition table. 634 * Returns the start index of next category. 635 */ 636 static u16 __init llc_find_next_offset(struct llc_conn_state *state, u16 offset) 637 { 638 const struct llc_conn_state_trans **next_trans; 639 u16 cnt = 0; 640 641 for (next_trans = state->transitions + offset; 642 (*next_trans)->ev; next_trans++) 643 ++cnt; 644 return cnt; 645 } 646 647 /** 648 * llc_build_offset_table - builds offset table of connection 649 * 650 * Fills offset table of connection state transition table 651 * (llc_offset_table). 652 */ 653 void __init llc_build_offset_table(void) 654 { 655 struct llc_conn_state *curr_state; 656 int state, ev_type, next_offset; 657 658 for (state = 0; state < NBR_CONN_STATES; state++) { 659 curr_state = &llc_conn_state_table[state]; 660 next_offset = 0; 661 for (ev_type = 0; ev_type < NBR_CONN_EV; ev_type++) { 662 llc_offset_table[state][ev_type] = next_offset; 663 next_offset += llc_find_next_offset(curr_state, 664 next_offset) + 1; 665 } 666 } 667 } 668 669 /** 670 * llc_find_offset - finds start offset of category of transitions 671 * @state: state of connection 672 * @ev_type: type of happened event 673 * 674 * Finds start offset of desired category of transitions. Returns the 675 * desired start offset. 676 */ 677 static int llc_find_offset(int state, int ev_type) 678 { 679 int rc = 0; 680 /* at this stage, llc_offset_table[..][2] is not important. it is for 681 * init_pf_cycle and I don't know what is it. 682 */ 683 switch (ev_type) { 684 case LLC_CONN_EV_TYPE_PRIM: 685 rc = llc_offset_table[state][0]; break; 686 case LLC_CONN_EV_TYPE_PDU: 687 rc = llc_offset_table[state][4]; break; 688 case LLC_CONN_EV_TYPE_SIMPLE: 689 rc = llc_offset_table[state][1]; break; 690 case LLC_CONN_EV_TYPE_P_TMR: 691 case LLC_CONN_EV_TYPE_ACK_TMR: 692 case LLC_CONN_EV_TYPE_REJ_TMR: 693 case LLC_CONN_EV_TYPE_BUSY_TMR: 694 rc = llc_offset_table[state][3]; break; 695 } 696 return rc; 697 } 698 699 /** 700 * llc_sap_add_socket - adds a socket to a SAP 701 * @sap: SAP 702 * @sk: socket 703 * 704 * This function adds a socket to the hash tables of a SAP. 705 */ 706 void llc_sap_add_socket(struct llc_sap *sap, struct sock *sk) 707 { 708 struct llc_sock *llc = llc_sk(sk); 709 struct hlist_head *dev_hb = llc_sk_dev_hash(sap, llc->dev->ifindex); 710 struct hlist_nulls_head *laddr_hb = llc_sk_laddr_hash(sap, &llc->laddr); 711 712 llc_sap_hold(sap); 713 llc_sk(sk)->sap = sap; 714 715 spin_lock_bh(&sap->sk_lock); 716 sock_set_flag(sk, SOCK_RCU_FREE); 717 sap->sk_count++; 718 sk_nulls_add_node_rcu(sk, laddr_hb); 719 hlist_add_head(&llc->dev_hash_node, dev_hb); 720 spin_unlock_bh(&sap->sk_lock); 721 } 722 723 /** 724 * llc_sap_remove_socket - removes a socket from SAP 725 * @sap: SAP 726 * @sk: socket 727 * 728 * This function removes a connection from the hash tables of a SAP if 729 * the connection was in this list. 730 */ 731 void llc_sap_remove_socket(struct llc_sap *sap, struct sock *sk) 732 { 733 struct llc_sock *llc = llc_sk(sk); 734 735 spin_lock_bh(&sap->sk_lock); 736 sk_nulls_del_node_init_rcu(sk); 737 hlist_del(&llc->dev_hash_node); 738 sap->sk_count--; 739 spin_unlock_bh(&sap->sk_lock); 740 llc_sap_put(sap); 741 } 742 743 /** 744 * llc_conn_rcv - sends received pdus to the connection state machine 745 * @sk: current connection structure. 746 * @skb: received frame. 747 * 748 * Sends received pdus to the connection state machine. 749 */ 750 static int llc_conn_rcv(struct sock *sk, struct sk_buff *skb) 751 { 752 struct llc_conn_state_ev *ev = llc_conn_ev(skb); 753 754 ev->type = LLC_CONN_EV_TYPE_PDU; 755 ev->reason = 0; 756 return llc_conn_state_process(sk, skb); 757 } 758 759 static struct sock *llc_create_incoming_sock(struct sock *sk, 760 struct net_device *dev, 761 struct llc_addr *saddr, 762 struct llc_addr *daddr) 763 { 764 struct sock *newsk = llc_sk_alloc(sock_net(sk), sk->sk_family, GFP_ATOMIC, 765 sk->sk_prot, 0); 766 struct llc_sock *newllc, *llc = llc_sk(sk); 767 768 if (!newsk) 769 goto out; 770 newllc = llc_sk(newsk); 771 memcpy(&newllc->laddr, daddr, sizeof(newllc->laddr)); 772 memcpy(&newllc->daddr, saddr, sizeof(newllc->daddr)); 773 newllc->dev = dev; 774 dev_hold(dev); 775 llc_sap_add_socket(llc->sap, newsk); 776 llc_sap_hold(llc->sap); 777 out: 778 return newsk; 779 } 780 781 void llc_conn_handler(struct llc_sap *sap, struct sk_buff *skb) 782 { 783 struct llc_addr saddr, daddr; 784 struct sock *sk; 785 786 llc_pdu_decode_sa(skb, saddr.mac); 787 llc_pdu_decode_ssap(skb, &saddr.lsap); 788 llc_pdu_decode_da(skb, daddr.mac); 789 llc_pdu_decode_dsap(skb, &daddr.lsap); 790 791 sk = __llc_lookup(sap, &saddr, &daddr, dev_net(skb->dev)); 792 if (!sk) 793 goto drop; 794 795 bh_lock_sock(sk); 796 /* 797 * This has to be done here and not at the upper layer ->accept 798 * method because of the way the PROCOM state machine works: 799 * it needs to set several state variables (see, for instance, 800 * llc_adm_actions_2 in net/llc/llc_c_st.c) and send a packet to 801 * the originator of the new connection, and this state has to be 802 * in the newly created struct sock private area. -acme 803 */ 804 if (unlikely(sk->sk_state == TCP_LISTEN)) { 805 struct sock *newsk = llc_create_incoming_sock(sk, skb->dev, 806 &saddr, &daddr); 807 if (!newsk) 808 goto drop_unlock; 809 skb_set_owner_r(skb, newsk); 810 } else { 811 /* 812 * Can't be skb_set_owner_r, this will be done at the 813 * llc_conn_state_process function, later on, when we will use 814 * skb_queue_rcv_skb to send it to upper layers, this is 815 * another trick required to cope with how the PROCOM state 816 * machine works. -acme 817 */ 818 skb_orphan(skb); 819 sock_hold(sk); 820 skb->sk = sk; 821 skb->destructor = sock_efree; 822 } 823 if (!sock_owned_by_user(sk)) 824 llc_conn_rcv(sk, skb); 825 else { 826 dprintk("%s: adding to backlog...\n", __func__); 827 llc_set_backlog_type(skb, LLC_PACKET); 828 if (sk_add_backlog(sk, skb, READ_ONCE(sk->sk_rcvbuf))) 829 goto drop_unlock; 830 } 831 out: 832 bh_unlock_sock(sk); 833 sock_put(sk); 834 return; 835 drop: 836 kfree_skb(skb); 837 return; 838 drop_unlock: 839 kfree_skb(skb); 840 goto out; 841 } 842 843 #undef LLC_REFCNT_DEBUG 844 #ifdef LLC_REFCNT_DEBUG 845 static atomic_t llc_sock_nr; 846 #endif 847 848 /** 849 * llc_backlog_rcv - Processes rx frames and expired timers. 850 * @sk: LLC sock (p8022 connection) 851 * @skb: queued rx frame or event 852 * 853 * This function processes frames that has received and timers that has 854 * expired during sending an I pdu (refer to data_req_handler). frames 855 * queue by llc_rcv function (llc_mac.c) and timers queue by timer 856 * callback functions(llc_c_ac.c). 857 */ 858 static int llc_backlog_rcv(struct sock *sk, struct sk_buff *skb) 859 { 860 int rc = 0; 861 struct llc_sock *llc = llc_sk(sk); 862 863 if (likely(llc_backlog_type(skb) == LLC_PACKET)) { 864 if (likely(llc->state > 1)) /* not closed */ 865 rc = llc_conn_rcv(sk, skb); 866 else 867 goto out_kfree_skb; 868 } else if (llc_backlog_type(skb) == LLC_EVENT) { 869 /* timer expiration event */ 870 if (likely(llc->state > 1)) /* not closed */ 871 rc = llc_conn_state_process(sk, skb); 872 else 873 goto out_kfree_skb; 874 } else { 875 printk(KERN_ERR "%s: invalid skb in backlog\n", __func__); 876 goto out_kfree_skb; 877 } 878 out: 879 return rc; 880 out_kfree_skb: 881 kfree_skb(skb); 882 goto out; 883 } 884 885 /** 886 * llc_sk_init - Initializes a socket with default llc values. 887 * @sk: socket to initialize. 888 * 889 * Initializes a socket with default llc values. 890 */ 891 static void llc_sk_init(struct sock *sk) 892 { 893 struct llc_sock *llc = llc_sk(sk); 894 895 llc->state = LLC_CONN_STATE_ADM; 896 llc->inc_cntr = llc->dec_cntr = 2; 897 llc->dec_step = llc->connect_step = 1; 898 899 timer_setup(&llc->ack_timer.timer, llc_conn_ack_tmr_cb, 0); 900 llc->ack_timer.expire = sysctl_llc2_ack_timeout; 901 902 timer_setup(&llc->pf_cycle_timer.timer, llc_conn_pf_cycle_tmr_cb, 0); 903 llc->pf_cycle_timer.expire = sysctl_llc2_p_timeout; 904 905 timer_setup(&llc->rej_sent_timer.timer, llc_conn_rej_tmr_cb, 0); 906 llc->rej_sent_timer.expire = sysctl_llc2_rej_timeout; 907 908 timer_setup(&llc->busy_state_timer.timer, llc_conn_busy_tmr_cb, 0); 909 llc->busy_state_timer.expire = sysctl_llc2_busy_timeout; 910 911 llc->n2 = 2; /* max retransmit */ 912 llc->k = 2; /* tx win size, will adjust dynam */ 913 llc->rw = 128; /* rx win size (opt and equal to 914 * tx_win of remote LLC) */ 915 skb_queue_head_init(&llc->pdu_unack_q); 916 sk->sk_backlog_rcv = llc_backlog_rcv; 917 } 918 919 /** 920 * llc_sk_alloc - Allocates LLC sock 921 * @net: network namespace 922 * @family: upper layer protocol family 923 * @priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc) 924 * @prot: struct proto associated with this new sock instance 925 * @kern: is this to be a kernel socket? 926 * 927 * Allocates a LLC sock and initializes it. Returns the new LLC sock 928 * or %NULL if there's no memory available for one 929 */ 930 struct sock *llc_sk_alloc(struct net *net, int family, gfp_t priority, struct proto *prot, int kern) 931 { 932 struct sock *sk = sk_alloc(net, family, priority, prot, kern); 933 934 if (!sk) 935 goto out; 936 llc_sk_init(sk); 937 sock_init_data(NULL, sk); 938 #ifdef LLC_REFCNT_DEBUG 939 atomic_inc(&llc_sock_nr); 940 printk(KERN_DEBUG "LLC socket %p created in %s, now we have %d alive\n", sk, 941 __func__, atomic_read(&llc_sock_nr)); 942 #endif 943 out: 944 return sk; 945 } 946 947 void llc_sk_stop_all_timers(struct sock *sk, bool sync) 948 { 949 struct llc_sock *llc = llc_sk(sk); 950 951 if (sync) { 952 del_timer_sync(&llc->pf_cycle_timer.timer); 953 del_timer_sync(&llc->ack_timer.timer); 954 del_timer_sync(&llc->rej_sent_timer.timer); 955 del_timer_sync(&llc->busy_state_timer.timer); 956 } else { 957 del_timer(&llc->pf_cycle_timer.timer); 958 del_timer(&llc->ack_timer.timer); 959 del_timer(&llc->rej_sent_timer.timer); 960 del_timer(&llc->busy_state_timer.timer); 961 } 962 963 llc->ack_must_be_send = 0; 964 llc->ack_pf = 0; 965 } 966 967 /** 968 * llc_sk_free - Frees a LLC socket 969 * @sk: - socket to free 970 * 971 * Frees a LLC socket 972 */ 973 void llc_sk_free(struct sock *sk) 974 { 975 struct llc_sock *llc = llc_sk(sk); 976 977 llc->state = LLC_CONN_OUT_OF_SVC; 978 /* Stop all (possibly) running timers */ 979 llc_sk_stop_all_timers(sk, true); 980 #ifdef DEBUG_LLC_CONN_ALLOC 981 printk(KERN_INFO "%s: unackq=%d, txq=%d\n", __func__, 982 skb_queue_len(&llc->pdu_unack_q), 983 skb_queue_len(&sk->sk_write_queue)); 984 #endif 985 skb_queue_purge(&sk->sk_receive_queue); 986 skb_queue_purge(&sk->sk_write_queue); 987 skb_queue_purge(&llc->pdu_unack_q); 988 #ifdef LLC_REFCNT_DEBUG 989 if (refcount_read(&sk->sk_refcnt) != 1) { 990 printk(KERN_DEBUG "Destruction of LLC sock %p delayed in %s, cnt=%d\n", 991 sk, __func__, refcount_read(&sk->sk_refcnt)); 992 printk(KERN_DEBUG "%d LLC sockets are still alive\n", 993 atomic_read(&llc_sock_nr)); 994 } else { 995 atomic_dec(&llc_sock_nr); 996 printk(KERN_DEBUG "LLC socket %p released in %s, %d are still alive\n", sk, 997 __func__, atomic_read(&llc_sock_nr)); 998 } 999 #endif 1000 sock_put(sk); 1001 } 1002 1003 /** 1004 * llc_sk_reset - resets a connection 1005 * @sk: LLC socket to reset 1006 * 1007 * Resets a connection to the out of service state. Stops its timers 1008 * and frees any frames in the queues of the connection. 1009 */ 1010 void llc_sk_reset(struct sock *sk) 1011 { 1012 struct llc_sock *llc = llc_sk(sk); 1013 1014 llc_conn_ac_stop_all_timers(sk, NULL); 1015 skb_queue_purge(&sk->sk_write_queue); 1016 skb_queue_purge(&llc->pdu_unack_q); 1017 llc->remote_busy_flag = 0; 1018 llc->cause_flag = 0; 1019 llc->retry_count = 0; 1020 llc_conn_set_p_flag(sk, 0); 1021 llc->f_flag = 0; 1022 llc->s_flag = 0; 1023 llc->ack_pf = 0; 1024 llc->first_pdu_Ns = 0; 1025 llc->ack_must_be_send = 0; 1026 llc->dec_step = 1; 1027 llc->inc_cntr = 2; 1028 llc->dec_cntr = 2; 1029 llc->X = 0; 1030 llc->failed_data_req = 0 ; 1031 llc->last_nr = 0; 1032 } 1033