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