linux/net/llc/llc_conn.c
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   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
  32static int llc_find_offset(int state, int ev_type);
  33static void llc_conn_send_pdus(struct sock *sk);
  34static int llc_conn_service(struct sock *sk, struct sk_buff *skb);
  35static int llc_exec_conn_trans_actions(struct sock *sk,
  36                                       struct llc_conn_state_trans *trans,
  37                                       struct sk_buff *ev);
  38static 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 */
  42static int llc_offset_table[NBR_CONN_STATES][NBR_CONN_EV];
  43
  44int sysctl_llc2_ack_timeout = LLC2_ACK_TIME * HZ;
  45int sysctl_llc2_p_timeout = LLC2_P_TIME * HZ;
  46int sysctl_llc2_rej_timeout = LLC2_REJ_TIME * HZ;
  47int 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 */
  59int 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        }
 189out_kfree_skb:
 190        kfree_skb(skb);
 191out_skb_put:
 192        kfree_skb(skb);
 193        return rc;
 194}
 195
 196void 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 */
 212void 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 */
 229void 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);
 259out:;
 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 */
 272void 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);
 300out:;
 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 */
 312int 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        }
 335out:
 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 */
 346static 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 */
 375static 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        }
 393out:
 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 */
 405static 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 */
 452static 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
 472static 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 */
 496static 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();
 506again:
 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;
 528found:
 529        rcu_read_unlock();
 530        return rc;
 531}
 532
 533struct 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
 545static 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
 556static 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();
 565again:
 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;
 587found:
 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 */
 602static 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
 614static 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 */
 629u8 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 */
 643static 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 */
 660void __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 */
 684static 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 */
 713void 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 */
 737void 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 */
 756static 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
 765static 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);
 783out:
 784        return newsk;
 785}
 786
 787void 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, sk->sk_rcvbuf))
 832                        goto drop_unlock;
 833        }
 834out:
 835        bh_unlock_sock(sk);
 836        sock_put(sk);
 837        return;
 838drop:
 839        kfree_skb(skb);
 840        return;
 841drop_unlock:
 842        kfree_skb(skb);
 843        goto out;
 844}
 845
 846#undef LLC_REFCNT_DEBUG
 847#ifdef LLC_REFCNT_DEBUG
 848static 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 */
 861static 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        }
 881out:
 882        return rc;
 883out_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 */
 894static 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 */
 934struct 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
 947out:
 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 */
 957void 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 */
 994void 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}
1017
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