net/llc/llc

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This source file includes following definitions.
llc_conn_state_process
llc_conn_send_pdu
llc_conn_rtn_pdu
llc_conn_resend_i_pdu_as_cmd
llc_conn_resend_i_pdu_as_rsp
llc_conn_remove_acked_pdus
llc_conn_send_pdus
llc_conn_service
llc_qualify_conn_ev
llc_exec_conn_trans_actions
llc_estab_match
__llc_lookup_established
llc_lookup_established
llc_listener_match
__llc_lookup_listener
llc_lookup_listener
__llc_lookup
llc_data_accept_state
llc_find_next_offset
llc_build_offset_table
llc_find_offset
llc_sap_add_socket
llc_sap_remove_socket
llc_conn_rcv
llc_create_incoming_sock
llc_conn_handler
llc_backlog_rcv
llc_sk_init
llc_sk_alloc
llc_sk_stop_all_timers
llc_sk_free
llc_sk_reset
   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  *      This function always consumes a reference to the skb.
  60  */
  61 int llc_conn_state_process(struct sock *sk, struct sk_buff *skb)
  62 {
  63         int rc;
  64         struct llc_sock *llc = llc_sk(skb->sk);
  65         struct llc_conn_state_ev *ev = llc_conn_ev(skb);
  66 
  67         ev->ind_prim = ev->cfm_prim = 0;
  68         /*
  69          * Send event to state machine
  70          */
  71         rc = llc_conn_service(skb->sk, skb);
  72         if (unlikely(rc != 0)) {
  73                 printk(KERN_ERR "%s: llc_conn_service failed\n", __func__);
  74                 goto out_skb_put;
  75         }
  76 
  77         switch (ev->ind_prim) {
  78         case LLC_DATA_PRIM:
  79                 skb_get(skb);
  80                 llc_save_primitive(sk, skb, LLC_DATA_PRIM);
  81                 if (unlikely(sock_queue_rcv_skb(sk, skb))) {
  82                         /*
  83                          * shouldn't happen
  84                          */
  85                         printk(KERN_ERR "%s: sock_queue_rcv_skb failed!\n",
  86                                __func__);
  87                         kfree_skb(skb);
  88                 }
  89                 break;
  90         case LLC_CONN_PRIM:
  91                 /*
  92                  * Can't be sock_queue_rcv_skb, because we have to leave the
  93                  * skb->sk pointing to the newly created struct sock in
  94                  * llc_conn_handler. -acme
  95                  */
  96                 skb_get(skb);
  97                 skb_queue_tail(&sk->sk_receive_queue, skb);
  98                 sk->sk_state_change(sk);
  99                 break;
 100         case LLC_DISC_PRIM:
 101                 sock_hold(sk);
 102                 if (sk->sk_type == SOCK_STREAM &&
 103                     sk->sk_state == TCP_ESTABLISHED) {
 104                         sk->sk_shutdown       = SHUTDOWN_MASK;
 105                         sk->sk_socket->state  = SS_UNCONNECTED;
 106                         sk->sk_state          = TCP_CLOSE;
 107                         if (!sock_flag(sk, SOCK_DEAD)) {
 108                                 sock_set_flag(sk, SOCK_DEAD);
 109                                 sk->sk_state_change(sk);
 110                         }
 111                 }
 112                 sock_put(sk);
 113                 break;
 114         case LLC_RESET_PRIM:
 115                 /*
 116                  * FIXME:
 117                  * RESET is not being notified to upper layers for now
 118                  */
 119                 printk(KERN_INFO "%s: received a reset ind!\n", __func__);
 120                 break;
 121         default:
 122                 if (ev->ind_prim)
 123                         printk(KERN_INFO "%s: received unknown %d prim!\n",
 124                                 __func__, ev->ind_prim);
 125                 /* No indication */
 126                 break;
 127         }
 128 
 129         switch (ev->cfm_prim) {
 130         case LLC_DATA_PRIM:
 131                 if (!llc_data_accept_state(llc->state))
 132                         sk->sk_write_space(sk);
 133                 else
 134                         rc = llc->failed_data_req = 1;
 135                 break;
 136         case LLC_CONN_PRIM:
 137                 if (sk->sk_type == SOCK_STREAM &&
 138                     sk->sk_state == TCP_SYN_SENT) {
 139                         if (ev->status) {
 140                                 sk->sk_socket->state = SS_UNCONNECTED;
 141                                 sk->sk_state         = TCP_CLOSE;
 142                         } else {
 143                                 sk->sk_socket->state = SS_CONNECTED;
 144                                 sk->sk_state         = TCP_ESTABLISHED;
 145                         }
 146                         sk->sk_state_change(sk);
 147                 }
 148                 break;
 149         case LLC_DISC_PRIM:
 150                 sock_hold(sk);
 151                 if (sk->sk_type == SOCK_STREAM && sk->sk_state == TCP_CLOSING) {
 152                         sk->sk_socket->state = SS_UNCONNECTED;
 153                         sk->sk_state         = TCP_CLOSE;
 154                         sk->sk_state_change(sk);
 155                 }
 156                 sock_put(sk);
 157                 break;
 158         case LLC_RESET_PRIM:
 159                 /*
 160                  * FIXME:
 161                  * RESET is not being notified to upper layers for now
 162                  */
 163                 printk(KERN_INFO "%s: received a reset conf!\n", __func__);
 164                 break;
 165         default:
 166                 if (ev->cfm_prim)
 167                         printk(KERN_INFO "%s: received unknown %d prim!\n",
 168                                         __func__, ev->cfm_prim);
 169                 /* No confirmation */
 170                 break;
 171         }
 172 out_skb_put:
 173         kfree_skb(skb);
 174         return rc;
 175 }
 176 
 177 void llc_conn_send_pdu(struct sock *sk, struct sk_buff *skb)
 178 {
 179         /* queue PDU to send to MAC layer */
 180         skb_queue_tail(&sk->sk_write_queue, skb);
 181         llc_conn_send_pdus(sk);
 182 }
 183 
 184 /**
 185  *      llc_conn_rtn_pdu - sends received data pdu to upper layer
 186  *      @sk: Active connection
 187  *      @skb: Received data frame
 188  *
 189  *      Sends received data pdu to upper layer (by using indicate function).
 190  *      Prepares service parameters (prim and prim_data). calling indication
 191  *      function will be done in llc_conn_state_process.
 192  */
 193 void llc_conn_rtn_pdu(struct sock *sk, struct sk_buff *skb)
 194 {
 195         struct llc_conn_state_ev *ev = llc_conn_ev(skb);
 196 
 197         ev->ind_prim = LLC_DATA_PRIM;
 198 }
 199 
 200 /**
 201  *      llc_conn_resend_i_pdu_as_cmd - resend all all unacknowledged I PDUs
 202  *      @sk: active connection
 203  *      @nr: NR
 204  *      @first_p_bit: p_bit value of first pdu
 205  *
 206  *      Resend all unacknowledged I PDUs, starting with the NR; send first as
 207  *      command PDU with P bit equal first_p_bit; if more than one send
 208  *      subsequent as command PDUs with P bit equal zero (0).
 209  */
 210 void llc_conn_resend_i_pdu_as_cmd(struct sock *sk, u8 nr, u8 first_p_bit)
 211 {
 212         struct sk_buff *skb;
 213         struct llc_pdu_sn *pdu;
 214         u16 nbr_unack_pdus;
 215         struct llc_sock *llc;
 216         u8 howmany_resend = 0;
 217 
 218         llc_conn_remove_acked_pdus(sk, nr, &nbr_unack_pdus);
 219         if (!nbr_unack_pdus)
 220                 goto out;
 221         /*
 222          * Process unack PDUs only if unack queue is not empty; remove
 223          * appropriate PDUs, fix them up, and put them on mac_pdu_q.
 224          */
 225         llc = llc_sk(sk);
 226 
 227         while ((skb = skb_dequeue(&llc->pdu_unack_q)) != NULL) {
 228                 pdu = llc_pdu_sn_hdr(skb);
 229                 llc_pdu_set_cmd_rsp(skb, LLC_PDU_CMD);
 230                 llc_pdu_set_pf_bit(skb, first_p_bit);
 231                 skb_queue_tail(&sk->sk_write_queue, skb);
 232                 first_p_bit = 0;
 233                 llc->vS = LLC_I_GET_NS(pdu);
 234                 howmany_resend++;
 235         }
 236         if (howmany_resend > 0)
 237                 llc->vS = (llc->vS + 1) % LLC_2_SEQ_NBR_MODULO;
 238         /* any PDUs to re-send are queued up; start sending to MAC */
 239         llc_conn_send_pdus(sk);
 240 out:;
 241 }
 242 
 243 /**
 244  *      llc_conn_resend_i_pdu_as_rsp - Resend all unacknowledged I PDUs
 245  *      @sk: active connection.
 246  *      @nr: NR
 247  *      @first_f_bit: f_bit value of first pdu.
 248  *
 249  *      Resend all unacknowledged I PDUs, starting with the NR; send first as
 250  *      response PDU with F bit equal first_f_bit; if more than one send
 251  *      subsequent as response PDUs with F bit equal zero (0).
 252  */
 253 void llc_conn_resend_i_pdu_as_rsp(struct sock *sk, u8 nr, u8 first_f_bit)
 254 {
 255         struct sk_buff *skb;
 256         u16 nbr_unack_pdus;
 257         struct llc_sock *llc = llc_sk(sk);
 258         u8 howmany_resend = 0;
 259 
 260         llc_conn_remove_acked_pdus(sk, nr, &nbr_unack_pdus);
 261         if (!nbr_unack_pdus)
 262                 goto out;
 263         /*
 264          * Process unack PDUs only if unack queue is not empty; remove
 265          * appropriate PDUs, fix them up, and put them on mac_pdu_q
 266          */
 267         while ((skb = skb_dequeue(&llc->pdu_unack_q)) != NULL) {
 268                 struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
 269 
 270                 llc_pdu_set_cmd_rsp(skb, LLC_PDU_RSP);
 271                 llc_pdu_set_pf_bit(skb, first_f_bit);
 272                 skb_queue_tail(&sk->sk_write_queue, skb);
 273                 first_f_bit = 0;
 274                 llc->vS = LLC_I_GET_NS(pdu);
 275                 howmany_resend++;
 276         }
 277         if (howmany_resend > 0)
 278                 llc->vS = (llc->vS + 1) % LLC_2_SEQ_NBR_MODULO;
 279         /* any PDUs to re-send are queued up; start sending to MAC */
 280         llc_conn_send_pdus(sk);
 281 out:;
 282 }
 283 
 284 /**
 285  *      llc_conn_remove_acked_pdus - Removes acknowledged pdus from tx queue
 286  *      @sk: active connection
 287  *      nr: NR
 288  *      how_many_unacked: size of pdu_unack_q after removing acked pdus
 289  *
 290  *      Removes acknowledged pdus from transmit queue (pdu_unack_q). Returns
 291  *      the number of pdus that removed from queue.
 292  */
 293 int llc_conn_remove_acked_pdus(struct sock *sk, u8 nr, u16 *how_many_unacked)
 294 {
 295         int pdu_pos, i;
 296         struct sk_buff *skb;
 297         struct llc_pdu_sn *pdu;
 298         int nbr_acked = 0;
 299         struct llc_sock *llc = llc_sk(sk);
 300         int q_len = skb_queue_len(&llc->pdu_unack_q);
 301 
 302         if (!q_len)
 303                 goto out;
 304         skb = skb_peek(&llc->pdu_unack_q);
 305         pdu = llc_pdu_sn_hdr(skb);
 306 
 307         /* finding position of last acked pdu in queue */
 308         pdu_pos = ((int)LLC_2_SEQ_NBR_MODULO + (int)nr -
 309                         (int)LLC_I_GET_NS(pdu)) % LLC_2_SEQ_NBR_MODULO;
 310 
 311         for (i = 0; i < pdu_pos && i < q_len; i++) {
 312                 skb = skb_dequeue(&llc->pdu_unack_q);
 313                 kfree_skb(skb);
 314                 nbr_acked++;
 315         }
 316 out:
 317         *how_many_unacked = skb_queue_len(&llc->pdu_unack_q);
 318         return nbr_acked;
 319 }
 320 
 321 /**
 322  *      llc_conn_send_pdus - Sends queued PDUs
 323  *      @sk: active connection
 324  *
 325  *      Sends queued pdus to MAC layer for transmission.
 326  */
 327 static void llc_conn_send_pdus(struct sock *sk)
 328 {
 329         struct sk_buff *skb;
 330 
 331         while ((skb = skb_dequeue(&sk->sk_write_queue)) != NULL) {
 332                 struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
 333 
 334                 if (LLC_PDU_TYPE_IS_I(pdu) &&
 335                     !(skb->dev->flags & IFF_LOOPBACK)) {
 336                         struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
 337 
 338                         skb_queue_tail(&llc_sk(sk)->pdu_unack_q, skb);
 339                         if (!skb2)
 340                                 break;
 341                         skb = skb2;
 342                 }
 343                 dev_queue_xmit(skb);
 344         }
 345 }
 346 
 347 /**
 348  *      llc_conn_service - finds transition and changes state of connection
 349  *      @sk: connection
 350  *      @skb: happened event
 351  *
 352  *      This function finds transition that matches with happened event, then
 353  *      executes related actions and finally changes state of connection.
 354  *      Returns 0 for success, 1 for failure.
 355  */
 356 static int llc_conn_service(struct sock *sk, struct sk_buff *skb)
 357 {
 358         int rc = 1;
 359         struct llc_sock *llc = llc_sk(sk);
 360         struct llc_conn_state_trans *trans;
 361 
 362         if (llc->state > NBR_CONN_STATES)
 363                 goto out;
 364         rc = 0;
 365         trans = llc_qualify_conn_ev(sk, skb);
 366         if (trans) {
 367                 rc = llc_exec_conn_trans_actions(sk, trans, skb);
 368                 if (!rc && trans->next_state != NO_STATE_CHANGE) {
 369                         llc->state = trans->next_state;
 370                         if (!llc_data_accept_state(llc->state))
 371                                 sk->sk_state_change(sk);
 372                 }
 373         }
 374 out:
 375         return rc;
 376 }
 377 
 378 /**
 379  *      llc_qualify_conn_ev - finds transition for event
 380  *      @sk: connection
 381  *      @skb: happened event
 382  *
 383  *      This function finds transition that matches with happened event.
 384  *      Returns pointer to found transition on success, %NULL otherwise.
 385  */
 386 static struct llc_conn_state_trans *llc_qualify_conn_ev(struct sock *sk,
 387                                                         struct sk_buff *skb)
 388 {
 389         struct llc_conn_state_trans **next_trans;
 390         const llc_conn_ev_qfyr_t *next_qualifier;
 391         struct llc_conn_state_ev *ev = llc_conn_ev(skb);
 392         struct llc_sock *llc = llc_sk(sk);
 393         struct llc_conn_state *curr_state =
 394                                         &llc_conn_state_table[llc->state - 1];
 395 
 396         /* search thru events for this state until
 397          * list exhausted or until no more
 398          */
 399         for (next_trans = curr_state->transitions +
 400                 llc_find_offset(llc->state - 1, ev->type);
 401              (*next_trans)->ev; next_trans++) {
 402                 if (!((*next_trans)->ev)(sk, skb)) {
 403                         /* got POSSIBLE event match; the event may require
 404                          * qualification based on the values of a number of
 405                          * state flags; if all qualifications are met (i.e.,
 406                          * if all qualifying functions return success, or 0,
 407                          * then this is THE event we're looking for
 408                          */
 409                         for (next_qualifier = (*next_trans)->ev_qualifiers;
 410                              next_qualifier && *next_qualifier &&
 411                              !(*next_qualifier)(sk, skb); next_qualifier++)
 412                                 /* nothing */;
 413                         if (!next_qualifier || !*next_qualifier)
 414                                 /* all qualifiers executed successfully; this is
 415                                  * our transition; return it so we can perform
 416                                  * the associated actions & change the state
 417                                  */
 418                                 return *next_trans;
 419                 }
 420         }
 421         return NULL;
 422 }
 423 
 424 /**
 425  *      llc_exec_conn_trans_actions - executes related actions
 426  *      @sk: connection
 427  *      @trans: transition that it's actions must be performed
 428  *      @skb: event
 429  *
 430  *      Executes actions that is related to happened event. Returns 0 for
 431  *      success, 1 to indicate failure of at least one action.
 432  */
 433 static int llc_exec_conn_trans_actions(struct sock *sk,
 434                                        struct llc_conn_state_trans *trans,
 435                                        struct sk_buff *skb)
 436 {
 437         int rc = 0;
 438         const llc_conn_action_t *next_action;
 439 
 440         for (next_action = trans->ev_actions;
 441              next_action && *next_action; next_action++) {
 442                 int rc2 = (*next_action)(sk, skb);
 443 
 444                 if (rc2 == 2) {
 445                         rc = rc2;
 446                         break;
 447                 } else if (rc2)
 448                         rc = 1;
 449         }
 450         return rc;
 451 }
 452 
 453 static inline bool llc_estab_match(const struct llc_sap *sap,
 454                                    const struct llc_addr *daddr,
 455                                    const struct llc_addr *laddr,
 456                                    const struct sock *sk)
 457 {
 458         struct llc_sock *llc = llc_sk(sk);
 459 
 460         return llc->laddr.lsap == laddr->lsap &&
 461                 llc->daddr.lsap == daddr->lsap &&
 462                 ether_addr_equal(llc->laddr.mac, laddr->mac) &&
 463                 ether_addr_equal(llc->daddr.mac, daddr->mac);
 464 }
 465 
 466 /**
 467  *      __llc_lookup_established - Finds connection for the remote/local sap/mac
 468  *      @sap: SAP
 469  *      @daddr: address of remote LLC (MAC + SAP)
 470  *      @laddr: address of local LLC (MAC + SAP)
 471  *
 472  *      Search connection list of the SAP and finds connection using the remote
 473  *      mac, remote sap, local mac, and local sap. Returns pointer for
 474  *      connection found, %NULL otherwise.
 475  *      Caller has to make sure local_bh is disabled.
 476  */
 477 static struct sock *__llc_lookup_established(struct llc_sap *sap,
 478                                              struct llc_addr *daddr,
 479                                              struct llc_addr *laddr)
 480 {
 481         struct sock *rc;
 482         struct hlist_nulls_node *node;
 483         int slot = llc_sk_laddr_hashfn(sap, laddr);
 484         struct hlist_nulls_head *laddr_hb = &sap->sk_laddr_hash[slot];
 485 
 486         rcu_read_lock();
 487 again:
 488         sk_nulls_for_each_rcu(rc, node, laddr_hb) {
 489                 if (llc_estab_match(sap, daddr, laddr, rc)) {
 490                         /* Extra checks required by SLAB_TYPESAFE_BY_RCU */
 491                         if (unlikely(!refcount_inc_not_zero(&rc->sk_refcnt)))
 492                                 goto again;
 493                         if (unlikely(llc_sk(rc)->sap != sap ||
 494                                      !llc_estab_match(sap, daddr, laddr, rc))) {
 495                                 sock_put(rc);
 496                                 continue;
 497                         }
 498                         goto found;
 499                 }
 500         }
 501         rc = NULL;
 502         /*
 503          * if the nulls value we got at the end of this lookup is
 504          * not the expected one, we must restart lookup.
 505          * We probably met an item that was moved to another chain.
 506          */
 507         if (unlikely(get_nulls_value(node) != slot))
 508                 goto again;
 509 found:
 510         rcu_read_unlock();
 511         return rc;
 512 }
 513 
 514 struct sock *llc_lookup_established(struct llc_sap *sap,
 515                                     struct llc_addr *daddr,
 516                                     struct llc_addr *laddr)
 517 {
 518         struct sock *sk;
 519 
 520         local_bh_disable();
 521         sk = __llc_lookup_established(sap, daddr, laddr);
 522         local_bh_enable();
 523         return sk;
 524 }
 525 
 526 static inline bool llc_listener_match(const struct llc_sap *sap,
 527                                       const struct llc_addr *laddr,
 528                                       const struct sock *sk)
 529 {
 530         struct llc_sock *llc = llc_sk(sk);
 531 
 532         return sk->sk_type == SOCK_STREAM && sk->sk_state == TCP_LISTEN &&
 533                 llc->laddr.lsap == laddr->lsap &&
 534                 ether_addr_equal(llc->laddr.mac, laddr->mac);
 535 }
 536 
 537 static struct sock *__llc_lookup_listener(struct llc_sap *sap,
 538                                           struct llc_addr *laddr)
 539 {
 540         struct sock *rc;
 541         struct hlist_nulls_node *node;
 542         int slot = llc_sk_laddr_hashfn(sap, laddr);
 543         struct hlist_nulls_head *laddr_hb = &sap->sk_laddr_hash[slot];
 544 
 545         rcu_read_lock();
 546 again:
 547         sk_nulls_for_each_rcu(rc, node, laddr_hb) {
 548                 if (llc_listener_match(sap, laddr, rc)) {
 549                         /* Extra checks required by SLAB_TYPESAFE_BY_RCU */
 550                         if (unlikely(!refcount_inc_not_zero(&rc->sk_refcnt)))
 551                                 goto again;
 552                         if (unlikely(llc_sk(rc)->sap != sap ||
 553                                      !llc_listener_match(sap, laddr, rc))) {
 554                                 sock_put(rc);
 555                                 continue;
 556                         }
 557                         goto found;
 558                 }
 559         }
 560         rc = NULL;
 561         /*
 562          * if the nulls value we got at the end of this lookup is
 563          * not the expected one, we must restart lookup.
 564          * We probably met an item that was moved to another chain.
 565          */
 566         if (unlikely(get_nulls_value(node) != slot))
 567                 goto again;
 568 found:
 569         rcu_read_unlock();
 570         return rc;
 571 }
 572 
 573 /**
 574  *      llc_lookup_listener - Finds listener for local MAC + SAP
 575  *      @sap: SAP
 576  *      @laddr: address of local LLC (MAC + SAP)
 577  *
 578  *      Search connection list of the SAP and finds connection listening on
 579  *      local mac, and local sap. Returns pointer for parent socket found,
 580  *      %NULL otherwise.
 581  *      Caller has to make sure local_bh is disabled.
 582  */
 583 static struct sock *llc_lookup_listener(struct llc_sap *sap,
 584                                         struct llc_addr *laddr)
 585 {
 586         static struct llc_addr null_addr;
 587         struct sock *rc = __llc_lookup_listener(sap, laddr);
 588 
 589         if (!rc)
 590                 rc = __llc_lookup_listener(sap, &null_addr);
 591 
 592         return rc;
 593 }
 594 
 595 static struct sock *__llc_lookup(struct llc_sap *sap,
 596                                  struct llc_addr *daddr,
 597                                  struct llc_addr *laddr)
 598 {
 599         struct sock *sk = __llc_lookup_established(sap, daddr, laddr);
 600 
 601         return sk ? : llc_lookup_listener(sap, laddr);
 602 }
 603 
 604 /**
 605  *      llc_data_accept_state - designates if in this state data can be sent.
 606  *      @state: state of connection.
 607  *
 608  *      Returns 0 if data can be sent, 1 otherwise.
 609  */
 610 u8 llc_data_accept_state(u8 state)
 611 {
 612         return state != LLC_CONN_STATE_NORMAL && state != LLC_CONN_STATE_BUSY &&
 613                state != LLC_CONN_STATE_REJ;
 614 }
 615 
 616 /**
 617  *      llc_find_next_offset - finds offset for next category of transitions
 618  *      @state: state table.
 619  *      @offset: start offset.
 620  *
 621  *      Finds offset of next category of transitions in transition table.
 622  *      Returns the start index of next category.
 623  */
 624 static u16 __init llc_find_next_offset(struct llc_conn_state *state, u16 offset)
 625 {
 626         u16 cnt = 0;
 627         struct llc_conn_state_trans **next_trans;
 628 
 629         for (next_trans = state->transitions + offset;
 630              (*next_trans)->ev; next_trans++)
 631                 ++cnt;
 632         return cnt;
 633 }
 634 
 635 /**
 636  *      llc_build_offset_table - builds offset table of connection
 637  *
 638  *      Fills offset table of connection state transition table
 639  *      (llc_offset_table).
 640  */
 641 void __init llc_build_offset_table(void)
 642 {
 643         struct llc_conn_state *curr_state;
 644         int state, ev_type, next_offset;
 645 
 646         for (state = 0; state < NBR_CONN_STATES; state++) {
 647                 curr_state = &llc_conn_state_table[state];
 648                 next_offset = 0;
 649                 for (ev_type = 0; ev_type < NBR_CONN_EV; ev_type++) {
 650                         llc_offset_table[state][ev_type] = next_offset;
 651                         next_offset += llc_find_next_offset(curr_state,
 652                                                             next_offset) + 1;
 653                 }
 654         }
 655 }
 656 
 657 /**
 658  *      llc_find_offset - finds start offset of category of transitions
 659  *      @state: state of connection
 660  *      @ev_type: type of happened event
 661  *
 662  *      Finds start offset of desired category of transitions. Returns the
 663  *      desired start offset.
 664  */
 665 static int llc_find_offset(int state, int ev_type)
 666 {
 667         int rc = 0;
 668         /* at this stage, llc_offset_table[..][2] is not important. it is for
 669          * init_pf_cycle and I don't know what is it.
 670          */
 671         switch (ev_type) {
 672         case LLC_CONN_EV_TYPE_PRIM:
 673                 rc = llc_offset_table[state][0]; break;
 674         case LLC_CONN_EV_TYPE_PDU:
 675                 rc = llc_offset_table[state][4]; break;
 676         case LLC_CONN_EV_TYPE_SIMPLE:
 677                 rc = llc_offset_table[state][1]; break;
 678         case LLC_CONN_EV_TYPE_P_TMR:
 679         case LLC_CONN_EV_TYPE_ACK_TMR:
 680         case LLC_CONN_EV_TYPE_REJ_TMR:
 681         case LLC_CONN_EV_TYPE_BUSY_TMR:
 682                 rc = llc_offset_table[state][3]; break;
 683         }
 684         return rc;
 685 }
 686 
 687 /**
 688  *      llc_sap_add_socket - adds a socket to a SAP
 689  *      @sap: SAP
 690  *      @sk: socket
 691  *
 692  *      This function adds a socket to the hash tables of a SAP.
 693  */
 694 void llc_sap_add_socket(struct llc_sap *sap, struct sock *sk)
 695 {
 696         struct llc_sock *llc = llc_sk(sk);
 697         struct hlist_head *dev_hb = llc_sk_dev_hash(sap, llc->dev->ifindex);
 698         struct hlist_nulls_head *laddr_hb = llc_sk_laddr_hash(sap, &llc->laddr);
 699 
 700         llc_sap_hold(sap);
 701         llc_sk(sk)->sap = sap;
 702 
 703         spin_lock_bh(&sap->sk_lock);
 704         sock_set_flag(sk, SOCK_RCU_FREE);
 705         sap->sk_count++;
 706         sk_nulls_add_node_rcu(sk, laddr_hb);
 707         hlist_add_head(&llc->dev_hash_node, dev_hb);
 708         spin_unlock_bh(&sap->sk_lock);
 709 }
 710 
 711 /**
 712  *      llc_sap_remove_socket - removes a socket from SAP
 713  *      @sap: SAP
 714  *      @sk: socket
 715  *
 716  *      This function removes a connection from the hash tables of a SAP if
 717  *      the connection was in this list.
 718  */
 719 void llc_sap_remove_socket(struct llc_sap *sap, struct sock *sk)
 720 {
 721         struct llc_sock *llc = llc_sk(sk);
 722 
 723         spin_lock_bh(&sap->sk_lock);
 724         sk_nulls_del_node_init_rcu(sk);
 725         hlist_del(&llc->dev_hash_node);
 726         sap->sk_count--;
 727         spin_unlock_bh(&sap->sk_lock);
 728         llc_sap_put(sap);
 729 }
 730 
 731 /**
 732  *      llc_conn_rcv - sends received pdus to the connection state machine
 733  *      @sk: current connection structure.
 734  *      @skb: received frame.
 735  *
 736  *      Sends received pdus to the connection state machine.
 737  */
 738 static int llc_conn_rcv(struct sock *sk, struct sk_buff *skb)
 739 {
 740         struct llc_conn_state_ev *ev = llc_conn_ev(skb);
 741 
 742         ev->type   = LLC_CONN_EV_TYPE_PDU;
 743         ev->reason = 0;
 744         return llc_conn_state_process(sk, skb);
 745 }
 746 
 747 static struct sock *llc_create_incoming_sock(struct sock *sk,
 748                                              struct net_device *dev,
 749                                              struct llc_addr *saddr,
 750                                              struct llc_addr *daddr)
 751 {
 752         struct sock *newsk = llc_sk_alloc(sock_net(sk), sk->sk_family, GFP_ATOMIC,
 753                                           sk->sk_prot, 0);
 754         struct llc_sock *newllc, *llc = llc_sk(sk);
 755 
 756         if (!newsk)
 757                 goto out;
 758         newllc = llc_sk(newsk);
 759         memcpy(&newllc->laddr, daddr, sizeof(newllc->laddr));
 760         memcpy(&newllc->daddr, saddr, sizeof(newllc->daddr));
 761         newllc->dev = dev;
 762         dev_hold(dev);
 763         llc_sap_add_socket(llc->sap, newsk);
 764         llc_sap_hold(llc->sap);
 765 out:
 766         return newsk;
 767 }
 768 
 769 void llc_conn_handler(struct llc_sap *sap, struct sk_buff *skb)
 770 {
 771         struct llc_addr saddr, daddr;
 772         struct sock *sk;
 773 
 774         llc_pdu_decode_sa(skb, saddr.mac);
 775         llc_pdu_decode_ssap(skb, &saddr.lsap);
 776         llc_pdu_decode_da(skb, daddr.mac);
 777         llc_pdu_decode_dsap(skb, &daddr.lsap);
 778 
 779         sk = __llc_lookup(sap, &saddr, &daddr);
 780         if (!sk)
 781                 goto drop;
 782 
 783         bh_lock_sock(sk);
 784         /*
 785          * This has to be done here and not at the upper layer ->accept
 786          * method because of the way the PROCOM state machine works:
 787          * it needs to set several state variables (see, for instance,
 788          * llc_adm_actions_2 in net/llc/llc_c_st.c) and send a packet to
 789          * the originator of the new connection, and this state has to be
 790          * in the newly created struct sock private area. -acme
 791          */
 792         if (unlikely(sk->sk_state == TCP_LISTEN)) {
 793                 struct sock *newsk = llc_create_incoming_sock(sk, skb->dev,
 794                                                               &saddr, &daddr);
 795                 if (!newsk)
 796                         goto drop_unlock;
 797                 skb_set_owner_r(skb, newsk);
 798         } else {
 799                 /*
 800                  * Can't be skb_set_owner_r, this will be done at the
 801                  * llc_conn_state_process function, later on, when we will use
 802                  * skb_queue_rcv_skb to send it to upper layers, this is
 803                  * another trick required to cope with how the PROCOM state
 804                  * machine works. -acme
 805                  */
 806                 skb_orphan(skb);
 807                 sock_hold(sk);
 808                 skb->sk = sk;
 809                 skb->destructor = sock_efree;
 810         }
 811         if (!sock_owned_by_user(sk))
 812                 llc_conn_rcv(sk, skb);
 813         else {
 814                 dprintk("%s: adding to backlog...\n", __func__);
 815                 llc_set_backlog_type(skb, LLC_PACKET);
 816                 if (sk_add_backlog(sk, skb, READ_ONCE(sk->sk_rcvbuf)))
 817                         goto drop_unlock;
 818         }
 819 out:
 820         bh_unlock_sock(sk);
 821         sock_put(sk);
 822         return;
 823 drop:
 824         kfree_skb(skb);
 825         return;
 826 drop_unlock:
 827         kfree_skb(skb);
 828         goto out;
 829 }
 830 
 831 #undef LLC_REFCNT_DEBUG
 832 #ifdef LLC_REFCNT_DEBUG
 833 static atomic_t llc_sock_nr;
 834 #endif
 835 
 836 /**
 837  *      llc_backlog_rcv - Processes rx frames and expired timers.
 838  *      @sk: LLC sock (p8022 connection)
 839  *      @skb: queued rx frame or event
 840  *
 841  *      This function processes frames that has received and timers that has
 842  *      expired during sending an I pdu (refer to data_req_handler).  frames
 843  *      queue by llc_rcv function (llc_mac.c) and timers queue by timer
 844  *      callback functions(llc_c_ac.c).
 845  */
 846 static int llc_backlog_rcv(struct sock *sk, struct sk_buff *skb)
 847 {
 848         int rc = 0;
 849         struct llc_sock *llc = llc_sk(sk);
 850 
 851         if (likely(llc_backlog_type(skb) == LLC_PACKET)) {
 852                 if (likely(llc->state > 1)) /* not closed */
 853                         rc = llc_conn_rcv(sk, skb);
 854                 else
 855                         goto out_kfree_skb;
 856         } else if (llc_backlog_type(skb) == LLC_EVENT) {
 857                 /* timer expiration event */
 858                 if (likely(llc->state > 1))  /* not closed */
 859                         rc = llc_conn_state_process(sk, skb);
 860                 else
 861                         goto out_kfree_skb;
 862         } else {
 863                 printk(KERN_ERR "%s: invalid skb in backlog\n", __func__);
 864                 goto out_kfree_skb;
 865         }
 866 out:
 867         return rc;
 868 out_kfree_skb:
 869         kfree_skb(skb);
 870         goto out;
 871 }
 872 
 873 /**
 874  *     llc_sk_init - Initializes a socket with default llc values.
 875  *     @sk: socket to initialize.
 876  *
 877  *     Initializes a socket with default llc values.
 878  */
 879 static void llc_sk_init(struct sock *sk)
 880 {
 881         struct llc_sock *llc = llc_sk(sk);
 882 
 883         llc->state    = LLC_CONN_STATE_ADM;
 884         llc->inc_cntr = llc->dec_cntr = 2;
 885         llc->dec_step = llc->connect_step = 1;
 886 
 887         timer_setup(&llc->ack_timer.timer, llc_conn_ack_tmr_cb, 0);
 888         llc->ack_timer.expire         = sysctl_llc2_ack_timeout;
 889 
 890         timer_setup(&llc->pf_cycle_timer.timer, llc_conn_pf_cycle_tmr_cb, 0);
 891         llc->pf_cycle_timer.expire         = sysctl_llc2_p_timeout;
 892 
 893         timer_setup(&llc->rej_sent_timer.timer, llc_conn_rej_tmr_cb, 0);
 894         llc->rej_sent_timer.expire         = sysctl_llc2_rej_timeout;
 895 
 896         timer_setup(&llc->busy_state_timer.timer, llc_conn_busy_tmr_cb, 0);
 897         llc->busy_state_timer.expire         = sysctl_llc2_busy_timeout;
 898 
 899         llc->n2 = 2;   /* max retransmit */
 900         llc->k  = 2;   /* tx win size, will adjust dynam */
 901         llc->rw = 128; /* rx win size (opt and equal to
 902                         * tx_win of remote LLC) */
 903         skb_queue_head_init(&llc->pdu_unack_q);
 904         sk->sk_backlog_rcv = llc_backlog_rcv;
 905 }
 906 
 907 /**
 908  *      llc_sk_alloc - Allocates LLC sock
 909  *      @family: upper layer protocol family
 910  *      @priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc)
 911  *
 912  *      Allocates a LLC sock and initializes it. Returns the new LLC sock
 913  *      or %NULL if there's no memory available for one
 914  */
 915 struct sock *llc_sk_alloc(struct net *net, int family, gfp_t priority, struct proto *prot, int kern)
 916 {
 917         struct sock *sk = sk_alloc(net, family, priority, prot, kern);
 918 
 919         if (!sk)
 920                 goto out;
 921         llc_sk_init(sk);
 922         sock_init_data(NULL, sk);
 923 #ifdef LLC_REFCNT_DEBUG
 924         atomic_inc(&llc_sock_nr);
 925         printk(KERN_DEBUG "LLC socket %p created in %s, now we have %d alive\n", sk,
 926                 __func__, atomic_read(&llc_sock_nr));
 927 #endif
 928 out:
 929         return sk;
 930 }
 931 
 932 void llc_sk_stop_all_timers(struct sock *sk, bool sync)
 933 {
 934         struct llc_sock *llc = llc_sk(sk);
 935 
 936         if (sync) {
 937                 del_timer_sync(&llc->pf_cycle_timer.timer);
 938                 del_timer_sync(&llc->ack_timer.timer);
 939                 del_timer_sync(&llc->rej_sent_timer.timer);
 940                 del_timer_sync(&llc->busy_state_timer.timer);
 941         } else {
 942                 del_timer(&llc->pf_cycle_timer.timer);
 943                 del_timer(&llc->ack_timer.timer);
 944                 del_timer(&llc->rej_sent_timer.timer);
 945                 del_timer(&llc->busy_state_timer.timer);
 946         }
 947 
 948         llc->ack_must_be_send = 0;
 949         llc->ack_pf = 0;
 950 }
 951 
 952 /**
 953  *      llc_sk_free - Frees a LLC socket
 954  *      @sk - socket to free
 955  *
 956  *      Frees a LLC socket
 957  */
 958 void llc_sk_free(struct sock *sk)
 959 {
 960         struct llc_sock *llc = llc_sk(sk);
 961 
 962         llc->state = LLC_CONN_OUT_OF_SVC;
 963         /* Stop all (possibly) running timers */
 964         llc_sk_stop_all_timers(sk, true);
 965 #ifdef DEBUG_LLC_CONN_ALLOC
 966         printk(KERN_INFO "%s: unackq=%d, txq=%d\n", __func__,
 967                 skb_queue_len(&llc->pdu_unack_q),
 968                 skb_queue_len(&sk->sk_write_queue));
 969 #endif
 970         skb_queue_purge(&sk->sk_receive_queue);
 971         skb_queue_purge(&sk->sk_write_queue);
 972         skb_queue_purge(&llc->pdu_unack_q);
 973 #ifdef LLC_REFCNT_DEBUG
 974         if (refcount_read(&sk->sk_refcnt) != 1) {
 975                 printk(KERN_DEBUG "Destruction of LLC sock %p delayed in %s, cnt=%d\n",
 976                         sk, __func__, refcount_read(&sk->sk_refcnt));
 977                 printk(KERN_DEBUG "%d LLC sockets are still alive\n",
 978                         atomic_read(&llc_sock_nr));
 979         } else {
 980                 atomic_dec(&llc_sock_nr);
 981                 printk(KERN_DEBUG "LLC socket %p released in %s, %d are still alive\n", sk,
 982                         __func__, atomic_read(&llc_sock_nr));
 983         }
 984 #endif
 985         sock_put(sk);
 986 }
 987 
 988 /**
 989  *      llc_sk_reset - resets a connection
 990  *      @sk: LLC socket to reset
 991  *
 992  *      Resets a connection to the out of service state. Stops its timers
 993  *      and frees any frames in the queues of the connection.
 994  */
 995 void llc_sk_reset(struct sock *sk)
 996 {
 997         struct llc_sock *llc = llc_sk(sk);
 998 
 999         llc_conn_ac_stop_all_timers(sk, NULL);
1000         skb_queue_purge(&sk->sk_write_queue);
1001         skb_queue_purge(&llc->pdu_unack_q);
1002         llc->remote_busy_flag   = 0;
1003         llc->cause_flag         = 0;
1004         llc->retry_count        = 0;
1005         llc_conn_set_p_flag(sk, 0);
1006         llc->f_flag             = 0;
1007         llc->s_flag             = 0;
1008         llc->ack_pf             = 0;
1009         llc->first_pdu_Ns       = 0;
1010         llc->ack_must_be_send   = 0;
1011         llc->dec_step           = 1;
1012         llc->inc_cntr           = 2;
1013         llc->dec_cntr           = 2;
1014         llc->X                  = 0;
1015         llc->failed_data_req    = 0 ;
1016         llc->last_nr            = 0;
1017 }
/* [<][>][^][v][top][bottom][index][help] */
root/net/llc/llc_conn.c

DEFINITIONS
