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