git.oblomov.eu Git - linux-2.6/blob - 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", __func__);
  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                                __func__);
 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", __func__);
 136                 kfree_skb(skb);
 137                 break;
 138         default:
 139                 if (ev->ind_prim) {
 140                         printk(KERN_INFO "%s: received unknown %d prim!\n",
 141                                 __func__, 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", __func__);
 183                 break;
 184         default:
 185                 if (ev->cfm_prim) {
 186                         printk(KERN_INFO "%s: received unknown %d prim!\n",
 187                                         __func__, 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                 kfree_skb(skb);
 336                 nbr_acked++;
 337         }
 338 out:
 339         *how_many_unacked = skb_queue_len(&llc->pdu_unack_q);
 340         return nbr_acked;
 341 }
 342
 343 /**
 344  *      llc_conn_send_pdus - Sends queued PDUs
 345  *      @sk: active connection
 346  *
 347  *      Sends queued pdus to MAC layer for transmission.
 348  */
 349 static void llc_conn_send_pdus(struct sock *sk)
 350 {
 351         struct sk_buff *skb;
 352
 353         while ((skb = skb_dequeue(&sk->sk_write_queue)) != NULL) {
 354                 struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
 355
 356                 if (LLC_PDU_TYPE_IS_I(pdu) &&
 357                     !(skb->dev->flags & IFF_LOOPBACK)) {
 358                         struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
 359
 360                         skb_queue_tail(&llc_sk(sk)->pdu_unack_q, skb);
 361                         if (!skb2)
 362                                 break;
 363                         skb = skb2;
 364                 }
 365                 dev_queue_xmit(skb);
 366         }
 367 }
 368
 369 /**
 370  *      llc_conn_service - finds transition and changes state of connection
 371  *      @sk: connection
 372  *      @skb: happened event
 373  *
 374  *      This function finds transition that matches with happened event, then
 375  *      executes related actions and finally changes state of connection.
 376  *      Returns 0 for success, 1 for failure.
 377  */
 378 static int llc_conn_service(struct sock *sk, struct sk_buff *skb)
 379 {
 380         int rc = 1;
 381         struct llc_sock *llc = llc_sk(sk);
 382         struct llc_conn_state_trans *trans;
 383
 384         if (llc->state > NBR_CONN_STATES)
 385                 goto out;
 386         rc = 0;
 387         trans = llc_qualify_conn_ev(sk, skb);
 388         if (trans) {
 389                 rc = llc_exec_conn_trans_actions(sk, trans, skb);
 390                 if (!rc && trans->next_state != NO_STATE_CHANGE) {
 391                         llc->state = trans->next_state;
 392                         if (!llc_data_accept_state(llc->state))
 393                                 sk->sk_state_change(sk);
 394                 }
 395         }
 396 out:
 397         return rc;
 398 }
 399
 400 /**
 401  *      llc_qualify_conn_ev - finds transition for event
 402  *      @sk: connection
 403  *      @skb: happened event
 404  *
 405  *      This function finds transition that matches with happened event.
 406  *      Returns pointer to found transition on success, %NULL otherwise.
 407  */
 408 static struct llc_conn_state_trans *llc_qualify_conn_ev(struct sock *sk,
 409                                                         struct sk_buff *skb)
 410 {
 411         struct llc_conn_state_trans **next_trans;
 412         llc_conn_ev_qfyr_t *next_qualifier;
 413         struct llc_conn_state_ev *ev = llc_conn_ev(skb);
 414         struct llc_sock *llc = llc_sk(sk);
 415         struct llc_conn_state *curr_state =
 416                                         &llc_conn_state_table[llc->state - 1];
 417
 418         /* search thru events for this state until
 419          * list exhausted or until no more
 420          */
 421         for (next_trans = curr_state->transitions +
 422                 llc_find_offset(llc->state - 1, ev->type);
 423              (*next_trans)->ev; next_trans++) {
 424                 if (!((*next_trans)->ev)(sk, skb)) {
 425                         /* got POSSIBLE event match; the event may require
 426                          * qualification based on the values of a number of
 427                          * state flags; if all qualifications are met (i.e.,
 428                          * if all qualifying functions return success, or 0,
 429                          * then this is THE event we're looking for
 430                          */
 431                         for (next_qualifier = (*next_trans)->ev_qualifiers;
 432                              next_qualifier && *next_qualifier &&
 433                              !(*next_qualifier)(sk, skb); next_qualifier++)
 434                                 /* nothing */;
 435                         if (!next_qualifier || !*next_qualifier)
 436                                 /* all qualifiers executed successfully; this is
 437                                  * our transition; return it so we can perform
 438                                  * the associated actions & change the state
 439                                  */
 440                                 return *next_trans;
 441                 }
 442         }
 443         return NULL;
 444 }
 445
 446 /**
 447  *      llc_exec_conn_trans_actions - executes related actions
 448  *      @sk: connection
 449  *      @trans: transition that it's actions must be performed
 450  *      @skb: event
 451  *
 452  *      Executes actions that is related to happened event. Returns 0 for
 453  *      success, 1 to indicate failure of at least one action.
 454  */
 455 static int llc_exec_conn_trans_actions(struct sock *sk,
 456                                        struct llc_conn_state_trans *trans,
 457                                        struct sk_buff *skb)
 458 {
 459         int rc = 0;
 460         llc_conn_action_t *next_action;
 461
 462         for (next_action = trans->ev_actions;
 463              next_action && *next_action; next_action++) {
 464                 int rc2 = (*next_action)(sk, skb);
 465
 466                 if (rc2 == 2) {
 467                         rc = rc2;
 468                         break;
 469                 } else if (rc2)
 470                         rc = 1;
 471         }
 472         return rc;
 473 }
 474
 475 /**
 476  *      __llc_lookup_established - Finds connection for the remote/local sap/mac
 477  *      @sap: SAP
 478  *      @daddr: address of remote LLC (MAC + SAP)
 479  *      @laddr: address of local LLC (MAC + SAP)
 480  *
 481  *      Search connection list of the SAP and finds connection using the remote
 482  *      mac, remote sap, local mac, and local sap. Returns pointer for
 483  *      connection found, %NULL otherwise.
 484  *      Caller has to make sure local_bh is disabled.
 485  */
 486 static struct sock *__llc_lookup_established(struct llc_sap *sap,
 487                                              struct llc_addr *daddr,
 488                                              struct llc_addr *laddr)
 489 {
 490         struct sock *rc;
 491         struct hlist_node *node;
 492
 493         read_lock(&sap->sk_list.lock);
 494         sk_for_each(rc, node, &sap->sk_list.list) {
 495                 struct llc_sock *llc = llc_sk(rc);
 496
 497                 if (llc->laddr.lsap == laddr->lsap &&
 498                     llc->daddr.lsap == daddr->lsap &&
 499                     llc_mac_match(llc->laddr.mac, laddr->mac) &&
 500                     llc_mac_match(llc->daddr.mac, daddr->mac)) {
 501                         sock_hold(rc);
 502                         goto found;
 503                 }
 504         }
 505         rc = NULL;
 506 found:
 507         read_unlock(&sap->sk_list.lock);
 508         return rc;
 509 }
 510
 511 struct sock *llc_lookup_established(struct llc_sap *sap,
 512                                     struct llc_addr *daddr,
 513                                     struct llc_addr *laddr)
 514 {
 515         struct sock *sk;
 516
 517         local_bh_disable();
 518         sk = __llc_lookup_established(sap, daddr, laddr);
 519         local_bh_enable();
 520         return sk;
 521 }
 522
 523 /**
 524  *      llc_lookup_listener - Finds listener for local MAC + SAP
 525  *      @sap: SAP
 526  *      @laddr: address of local LLC (MAC + SAP)
 527  *
 528  *      Search connection list of the SAP and finds connection listening on
 529  *      local mac, and local sap. Returns pointer for parent socket found,
 530  *      %NULL otherwise.
 531  *      Caller has to make sure local_bh is disabled.
 532  */
 533 static struct sock *llc_lookup_listener(struct llc_sap *sap,
 534                                         struct llc_addr *laddr)
 535 {
 536         struct sock *rc;
 537         struct hlist_node *node;
 538
 539         read_lock(&sap->sk_list.lock);
 540         sk_for_each(rc, node, &sap->sk_list.list) {
 541                 struct llc_sock *llc = llc_sk(rc);
 542
 543                 if (rc->sk_type == SOCK_STREAM && rc->sk_state == TCP_LISTEN &&
 544                     llc->laddr.lsap == laddr->lsap &&
 545                     (llc_mac_match(llc->laddr.mac, laddr->mac) ||
 546                      llc_mac_null(llc->laddr.mac))) {
 547                         sock_hold(rc);
 548                         goto found;
 549                 }
 550         }
 551         rc = NULL;
 552 found:
 553         read_unlock(&sap->sk_list.lock);
 554         return rc;
 555 }
 556
 557 static struct sock *__llc_lookup(struct llc_sap *sap,
 558                                  struct llc_addr *daddr,
 559                                  struct llc_addr *laddr)
 560 {
 561         struct sock *sk = __llc_lookup_established(sap, daddr, laddr);
 562
 563         return sk ? : llc_lookup_listener(sap, laddr);
 564 }
 565
 566 /**
 567  *      llc_data_accept_state - designates if in this state data can be sent.
 568  *      @state: state of connection.
 569  *
 570  *      Returns 0 if data can be sent, 1 otherwise.
 571  */
 572 u8 llc_data_accept_state(u8 state)
 573 {
 574         return state != LLC_CONN_STATE_NORMAL && state != LLC_CONN_STATE_BUSY &&
 575                state != LLC_CONN_STATE_REJ;
 576 }
 577
 578 /**
 579  *      llc_find_next_offset - finds offset for next category of transitions
 580  *      @state: state table.
 581  *      @offset: start offset.
 582  *
 583  *      Finds offset of next category of transitions in transition table.
 584  *      Returns the start index of next category.
 585  */
 586 static u16 __init llc_find_next_offset(struct llc_conn_state *state, u16 offset)
 587 {
 588         u16 cnt = 0;
 589         struct llc_conn_state_trans **next_trans;
 590
 591         for (next_trans = state->transitions + offset;
 592              (*next_trans)->ev; next_trans++)
 593                 ++cnt;
 594         return cnt;
 595 }
 596
 597 /**
 598  *      llc_build_offset_table - builds offset table of connection
 599  *
 600  *      Fills offset table of connection state transition table
 601  *      (llc_offset_table).
 602  */
 603 void __init llc_build_offset_table(void)
 604 {
 605         struct llc_conn_state *curr_state;
 606         int state, ev_type, next_offset;
 607
 608         for (state = 0; state < NBR_CONN_STATES; state++) {
 609                 curr_state = &llc_conn_state_table[state];
 610                 next_offset = 0;
 611                 for (ev_type = 0; ev_type < NBR_CONN_EV; ev_type++) {
 612                         llc_offset_table[state][ev_type] = next_offset;
 613                         next_offset += llc_find_next_offset(curr_state,
 614                                                             next_offset) + 1;
 615                 }
 616         }
 617 }
 618
 619 /**
 620  *      llc_find_offset - finds start offset of category of transitions
 621  *      @state: state of connection
 622  *      @ev_type: type of happened event
 623  *
 624  *      Finds start offset of desired category of transitions. Returns the
 625  *      desired start offset.
 626  */
 627 static int llc_find_offset(int state, int ev_type)
 628 {
 629         int rc = 0;
 630         /* at this stage, llc_offset_table[..][2] is not important. it is for
 631          * init_pf_cycle and I don't know what is it.
 632          */
 633         switch (ev_type) {
 634         case LLC_CONN_EV_TYPE_PRIM:
 635                 rc = llc_offset_table[state][0]; break;
 636         case LLC_CONN_EV_TYPE_PDU:
 637                 rc = llc_offset_table[state][4]; break;
 638         case LLC_CONN_EV_TYPE_SIMPLE:
 639                 rc = llc_offset_table[state][1]; break;
 640         case LLC_CONN_EV_TYPE_P_TMR:
 641         case LLC_CONN_EV_TYPE_ACK_TMR:
 642         case LLC_CONN_EV_TYPE_REJ_TMR:
 643         case LLC_CONN_EV_TYPE_BUSY_TMR:
 644                 rc = llc_offset_table[state][3]; break;
 645         }
 646         return rc;
 647 }
 648
 649 /**
 650  *      llc_sap_add_socket - adds a socket to a SAP
 651  *      @sap: SAP
 652  *      @sk: socket
 653  *
 654  *      This function adds a socket to sk_list of a SAP.
 655  */
 656 void llc_sap_add_socket(struct llc_sap *sap, struct sock *sk)
 657 {
 658         llc_sap_hold(sap);
 659         write_lock_bh(&sap->sk_list.lock);
 660         llc_sk(sk)->sap = sap;
 661         sk_add_node(sk, &sap->sk_list.list);
 662         write_unlock_bh(&sap->sk_list.lock);
 663 }
 664
 665 /**
 666  *      llc_sap_remove_socket - removes a socket from SAP
 667  *      @sap: SAP
 668  *      @sk: socket
 669  *
 670  *      This function removes a connection from sk_list.list of a SAP if
 671  *      the connection was in this list.
 672  */
 673 void llc_sap_remove_socket(struct llc_sap *sap, struct sock *sk)
 674 {
 675         write_lock_bh(&sap->sk_list.lock);
 676         sk_del_node_init(sk);
 677         write_unlock_bh(&sap->sk_list.lock);
 678         llc_sap_put(sap);
 679 }
 680
 681 /**
 682  *      llc_conn_rcv - sends received pdus to the connection state machine
 683  *      @sk: current connection structure.
 684  *      @skb: received frame.
 685  *
 686  *      Sends received pdus to the connection state machine.
 687  */
 688 static int llc_conn_rcv(struct sock* sk, struct sk_buff *skb)
 689 {
 690         struct llc_conn_state_ev *ev = llc_conn_ev(skb);
 691
 692         ev->type   = LLC_CONN_EV_TYPE_PDU;
 693         ev->reason = 0;
 694         return llc_conn_state_process(sk, skb);
 695 }
 696
 697 static struct sock *llc_create_incoming_sock(struct sock *sk,
 698                                              struct net_device *dev,
 699                                              struct llc_addr *saddr,
 700                                              struct llc_addr *daddr)
 701 {
 702         struct sock *newsk = llc_sk_alloc(sock_net(sk), sk->sk_family, GFP_ATOMIC,
 703                                           sk->sk_prot);
 704         struct llc_sock *newllc, *llc = llc_sk(sk);
 705
 706         if (!newsk)
 707                 goto out;
 708         newllc = llc_sk(newsk);
 709         memcpy(&newllc->laddr, daddr, sizeof(newllc->laddr));
 710         memcpy(&newllc->daddr, saddr, sizeof(newllc->daddr));
 711         newllc->dev = dev;
 712         dev_hold(dev);
 713         llc_sap_add_socket(llc->sap, newsk);
 714         llc_sap_hold(llc->sap);
 715 out:
 716         return newsk;
 717 }
 718
 719 void llc_conn_handler(struct llc_sap *sap, struct sk_buff *skb)
 720 {
 721         struct llc_addr saddr, daddr;
 722         struct sock *sk;
 723
 724         llc_pdu_decode_sa(skb, saddr.mac);
 725         llc_pdu_decode_ssap(skb, &saddr.lsap);
 726         llc_pdu_decode_da(skb, daddr.mac);
 727         llc_pdu_decode_dsap(skb, &daddr.lsap);
 728
 729         sk = __llc_lookup(sap, &saddr, &daddr);
 730         if (!sk)
 731                 goto drop;
 732
 733         bh_lock_sock(sk);
 734         /*
 735          * This has to be done here and not at the upper layer ->accept
 736          * method because of the way the PROCOM state machine works:
 737          * it needs to set several state variables (see, for instance,
 738          * llc_adm_actions_2 in net/llc/llc_c_st.c) and send a packet to
 739          * the originator of the new connection, and this state has to be
 740          * in the newly created struct sock private area. -acme
 741          */
 742         if (unlikely(sk->sk_state == TCP_LISTEN)) {
 743                 struct sock *newsk = llc_create_incoming_sock(sk, skb->dev,
 744                                                               &saddr, &daddr);
 745                 if (!newsk)
 746                         goto drop_unlock;
 747                 skb_set_owner_r(skb, newsk);
 748         } else {
 749                 /*
 750                  * Can't be skb_set_owner_r, this will be done at the
 751                  * llc_conn_state_process function, later on, when we will use
 752                  * skb_queue_rcv_skb to send it to upper layers, this is
 753                  * another trick required to cope with how the PROCOM state
 754                  * machine works. -acme
 755                  */
 756                 skb->sk = sk;
 757         }
 758         if (!sock_owned_by_user(sk))
 759                 llc_conn_rcv(sk, skb);
 760         else {
 761                 dprintk("%s: adding to backlog...\n", __func__);
 762                 llc_set_backlog_type(skb, LLC_PACKET);
 763                 sk_add_backlog(sk, skb);
 764         }
 765 out:
 766         bh_unlock_sock(sk);
 767         sock_put(sk);
 768         return;
 769 drop:
 770         kfree_skb(skb);
 771         return;
 772 drop_unlock:
 773         kfree_skb(skb);
 774         goto out;
 775 }
 776
 777 #undef LLC_REFCNT_DEBUG
 778 #ifdef LLC_REFCNT_DEBUG
 779 static atomic_t llc_sock_nr;
 780 #endif
 781
 782 /**
 783  *      llc_backlog_rcv - Processes rx frames and expired timers.
 784  *      @sk: LLC sock (p8022 connection)
 785  *      @skb: queued rx frame or event
 786  *
 787  *      This function processes frames that has received and timers that has
 788  *      expired during sending an I pdu (refer to data_req_handler).  frames
 789  *      queue by llc_rcv function (llc_mac.c) and timers queue by timer
 790  *      callback functions(llc_c_ac.c).
 791  */
 792 static int llc_backlog_rcv(struct sock *sk, struct sk_buff *skb)
 793 {
 794         int rc = 0;
 795         struct llc_sock *llc = llc_sk(sk);
 796
 797         if (likely(llc_backlog_type(skb) == LLC_PACKET)) {
 798                 if (likely(llc->state > 1)) /* not closed */
 799                         rc = llc_conn_rcv(sk, skb);
 800                 else
 801                         goto out_kfree_skb;
 802         } else if (llc_backlog_type(skb) == LLC_EVENT) {
 803                 /* timer expiration event */
 804                 if (likely(llc->state > 1))  /* not closed */
 805                         rc = llc_conn_state_process(sk, skb);
 806                 else
 807                         goto out_kfree_skb;
 808         } else {
 809                 printk(KERN_ERR "%s: invalid skb in backlog\n", __func__);
 810                 goto out_kfree_skb;
 811         }
 812 out:
 813         return rc;
 814 out_kfree_skb:
 815         kfree_skb(skb);
 816         goto out;
 817 }
 818
 819 /**
 820  *     llc_sk_init - Initializes a socket with default llc values.
 821  *     @sk: socket to initialize.
 822  *
 823  *     Initializes a socket with default llc values.
 824  */
 825 static void llc_sk_init(struct sock* sk)
 826 {
 827         struct llc_sock *llc = llc_sk(sk);
 828
 829         llc->state    = LLC_CONN_STATE_ADM;
 830         llc->inc_cntr = llc->dec_cntr = 2;
 831         llc->dec_step = llc->connect_step = 1;
 832
 833         setup_timer(&llc->ack_timer.timer, llc_conn_ack_tmr_cb,
 834                         (unsigned long)sk);
 835         llc->ack_timer.expire         = sysctl_llc2_ack_timeout;
 836
 837         setup_timer(&llc->pf_cycle_timer.timer, llc_conn_pf_cycle_tmr_cb,
 838                         (unsigned long)sk);
 839         llc->pf_cycle_timer.expire         = sysctl_llc2_p_timeout;
 840
 841         setup_timer(&llc->rej_sent_timer.timer, llc_conn_rej_tmr_cb,
 842                         (unsigned long)sk);
 843         llc->rej_sent_timer.expire         = sysctl_llc2_rej_timeout;
 844
 845         setup_timer(&llc->busy_state_timer.timer, llc_conn_busy_tmr_cb,
 846                         (unsigned long)sk);
 847         llc->busy_state_timer.expire         = sysctl_llc2_busy_timeout;
 848
 849         llc->n2 = 2;   /* max retransmit */
 850         llc->k  = 2;   /* tx win size, will adjust dynam */
 851         llc->rw = 128; /* rx win size (opt and equal to
 852                         * tx_win of remote LLC) */
 853         skb_queue_head_init(&llc->pdu_unack_q);
 854         sk->sk_backlog_rcv = llc_backlog_rcv;
 855 }
 856
 857 /**
 858  *      llc_sk_alloc - Allocates LLC sock
 859  *      @family: upper layer protocol family
 860  *      @priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc)
 861  *
 862  *      Allocates a LLC sock and initializes it. Returns the new LLC sock
 863  *      or %NULL if there's no memory available for one
 864  */
 865 struct sock *llc_sk_alloc(struct net *net, int family, gfp_t priority, struct proto *prot)
 866 {
 867         struct sock *sk = sk_alloc(net, family, priority, prot);
 868
 869         if (!sk)
 870                 goto out;
 871         llc_sk_init(sk);
 872         sock_init_data(NULL, sk);
 873 #ifdef LLC_REFCNT_DEBUG
 874         atomic_inc(&llc_sock_nr);
 875         printk(KERN_DEBUG "LLC socket %p created in %s, now we have %d alive\n", sk,
 876                 __func__, atomic_read(&llc_sock_nr));
 877 #endif
 878 out:
 879         return sk;
 880 }
 881
 882 /**
 883  *      llc_sk_free - Frees a LLC socket
 884  *      @sk - socket to free
 885  *
 886  *      Frees a LLC socket
 887  */
 888 void llc_sk_free(struct sock *sk)
 889 {
 890         struct llc_sock *llc = llc_sk(sk);
 891
 892         llc->state = LLC_CONN_OUT_OF_SVC;
 893         /* Stop all (possibly) running timers */
 894         llc_conn_ac_stop_all_timers(sk, NULL);
 895 #ifdef DEBUG_LLC_CONN_ALLOC
 896         printk(KERN_INFO "%s: unackq=%d, txq=%d\n", __func__,
 897                 skb_queue_len(&llc->pdu_unack_q),
 898                 skb_queue_len(&sk->sk_write_queue));
 899 #endif
 900         skb_queue_purge(&sk->sk_receive_queue);
 901         skb_queue_purge(&sk->sk_write_queue);
 902         skb_queue_purge(&llc->pdu_unack_q);
 903 #ifdef LLC_REFCNT_DEBUG
 904         if (atomic_read(&sk->sk_refcnt) != 1) {
 905                 printk(KERN_DEBUG "Destruction of LLC sock %p delayed in %s, cnt=%d\n",
 906                         sk, __func__, atomic_read(&sk->sk_refcnt));
 907                 printk(KERN_DEBUG "%d LLC sockets are still alive\n",
 908                         atomic_read(&llc_sock_nr));
 909         } else {
 910                 atomic_dec(&llc_sock_nr);
 911                 printk(KERN_DEBUG "LLC socket %p released in %s, %d are still alive\n", sk,
 912                         __func__, atomic_read(&llc_sock_nr));
 913         }
 914 #endif
 915         sock_put(sk);
 916 }
 917
 918 /**
 919  *      llc_sk_reset - resets a connection
 920  *      @sk: LLC socket to reset
 921  *
 922  *      Resets a connection to the out of service state. Stops its timers
 923  *      and frees any frames in the queues of the connection.
 924  */
 925 void llc_sk_reset(struct sock *sk)
 926 {
 927         struct llc_sock *llc = llc_sk(sk);
 928
 929         llc_conn_ac_stop_all_timers(sk, NULL);
 930         skb_queue_purge(&sk->sk_write_queue);
 931         skb_queue_purge(&llc->pdu_unack_q);
 932         llc->remote_busy_flag   = 0;
 933         llc->cause_flag         = 0;
 934         llc->retry_count        = 0;
 935         llc_conn_set_p_flag(sk, 0);
 936         llc->f_flag             = 0;
 937         llc->s_flag             = 0;
 938         llc->ack_pf             = 0;
 939         llc->first_pdu_Ns       = 0;
 940         llc->ack_must_be_send   = 0;
 941         llc->dec_step           = 1;
 942         llc->inc_cntr           = 2;
 943         llc->dec_cntr           = 2;
 944         llc->X                  = 0;
 945         llc->failed_data_req    = 0 ;
 946         llc->last_nr            = 0;
 947 }