net/llc/llc_conn.c

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