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