net/tipc/link.c

   1 /*
   2  * net/tipc/link.c: TIPC link code
   3  *
   4  * Copyright (c) 1996-2007, Ericsson AB
   5  * Copyright (c) 2004-2007, 2010-2011, Wind River Systems
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. Neither the names of the copyright holders nor the names of its
  17  *    contributors may be used to endorse or promote products derived from
  18  *    this software without specific prior written permission.
  19  *
  20  * Alternatively, this software may be distributed under the terms of the
  21  * GNU General Public License ("GPL") version 2 as published by the Free
  22  * Software Foundation.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  25  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  28  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  29  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  30  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  31  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  32  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  33  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  34  * POSSIBILITY OF SUCH DAMAGE.
  35  */
  36
  37 #include "core.h"
  38 #include "link.h"
  39 #include "port.h"
  40 #include "name_distr.h"
  41 #include "discover.h"
  42 #include "config.h"
  43
  44 /*
  45  * Error message prefixes
  46  */
  47 static const char *link_co_err = "Link changeover error, ";
  48 static const char *link_rst_msg = "Resetting link ";
  49 static const char *link_unk_evt = "Unknown link event ";
  50
  51 /*
  52  * Out-of-range value for link session numbers
  53  */
  54 #define INVALID_SESSION 0x10000
  55
  56 /*
  57  * Link state events:
  58  */
  59 #define  STARTING_EVT    856384768      /* link processing trigger */
  60 #define  TRAFFIC_MSG_EVT 560815u        /* rx'd ??? */
  61 #define  TIMEOUT_EVT     560817u        /* link timer expired */
  62
  63 /*
  64  * The following two 'message types' is really just implementation
  65  * data conveniently stored in the message header.
  66  * They must not be considered part of the protocol
  67  */
  68 #define OPEN_MSG   0
  69 #define CLOSED_MSG 1
  70
  71 /*
  72  * State value stored in 'exp_msg_count'
  73  */
  74 #define START_CHANGEOVER 100000u
  75
  76 /**
  77  * struct tipc_link_name - deconstructed link name
  78  * @addr_local: network address of node at this end
  79  * @if_local: name of interface at this end
  80  * @addr_peer: network address of node at far end
  81  * @if_peer: name of interface at far end
  82  */
  83 struct tipc_link_name {
  84         u32 addr_local;
  85         char if_local[TIPC_MAX_IF_NAME];
  86         u32 addr_peer;
  87         char if_peer[TIPC_MAX_IF_NAME];
  88 };
  89
  90 static void link_handle_out_of_seq_msg(struct tipc_link *l_ptr,
  91                                        struct sk_buff *buf);
  92 static void link_recv_proto_msg(struct tipc_link *l_ptr, struct sk_buff *buf);
  93 static int  link_recv_changeover_msg(struct tipc_link **l_ptr,
  94                                      struct sk_buff **buf);
  95 static void link_set_supervision_props(struct tipc_link *l_ptr, u32 tolerance);
  96 static int  link_send_sections_long(struct tipc_port *sender,
  97                                     struct iovec const *msg_sect,
  98                                     u32 num_sect, unsigned int total_len,
  99                                     u32 destnode);
 100 static void link_check_defragm_bufs(struct tipc_link *l_ptr);
 101 static void link_state_event(struct tipc_link *l_ptr, u32 event);
 102 static void link_reset_statistics(struct tipc_link *l_ptr);
 103 static void link_print(struct tipc_link *l_ptr, const char *str);
 104 static void link_start(struct tipc_link *l_ptr);
 105 static int link_send_long_buf(struct tipc_link *l_ptr, struct sk_buff *buf);
 106
 107 /*
 108  *  Simple link routines
 109  */
 110 static unsigned int align(unsigned int i)
 111 {
 112         return (i + 3) & ~3u;
 113 }
 114
 115 static void link_init_max_pkt(struct tipc_link *l_ptr)
 116 {
 117         u32 max_pkt;
 118
 119         max_pkt = (l_ptr->b_ptr->mtu & ~3);
 120         if (max_pkt > MAX_MSG_SIZE)
 121                 max_pkt = MAX_MSG_SIZE;
 122
 123         l_ptr->max_pkt_target = max_pkt;
 124         if (l_ptr->max_pkt_target < MAX_PKT_DEFAULT)
 125                 l_ptr->max_pkt = l_ptr->max_pkt_target;
 126         else
 127                 l_ptr->max_pkt = MAX_PKT_DEFAULT;
 128
 129         l_ptr->max_pkt_probes = 0;
 130 }
 131
 132 static u32 link_next_sent(struct tipc_link *l_ptr)
 133 {
 134         if (l_ptr->next_out)
 135                 return buf_seqno(l_ptr->next_out);
 136         return mod(l_ptr->next_out_no);
 137 }
 138
 139 static u32 link_last_sent(struct tipc_link *l_ptr)
 140 {
 141         return mod(link_next_sent(l_ptr) - 1);
 142 }
 143
 144 /*
 145  *  Simple non-static link routines (i.e. referenced outside this file)
 146  */
 147 int tipc_link_is_up(struct tipc_link *l_ptr)
 148 {
 149         if (!l_ptr)
 150                 return 0;
 151         return link_working_working(l_ptr) || link_working_unknown(l_ptr);
 152 }
 153
 154 int tipc_link_is_active(struct tipc_link *l_ptr)
 155 {
 156         return  (l_ptr->owner->active_links[0] == l_ptr) ||
 157                 (l_ptr->owner->active_links[1] == l_ptr);
 158 }
 159
 160 /**
 161  * link_name_validate - validate & (optionally) deconstruct tipc_link name
 162  * @name: ptr to link name string
 163  * @name_parts: ptr to area for link name components (or NULL if not needed)
 164  *
 165  * Returns 1 if link name is valid, otherwise 0.
 166  */
 167 static int link_name_validate(const char *name,
 168                                 struct tipc_link_name *name_parts)
 169 {
 170         char name_copy[TIPC_MAX_LINK_NAME];
 171         char *addr_local;
 172         char *if_local;
 173         char *addr_peer;
 174         char *if_peer;
 175         char dummy;
 176         u32 z_local, c_local, n_local;
 177         u32 z_peer, c_peer, n_peer;
 178         u32 if_local_len;
 179         u32 if_peer_len;
 180
 181         /* copy link name & ensure length is OK */
 182         name_copy[TIPC_MAX_LINK_NAME - 1] = 0;
 183         /* need above in case non-Posix strncpy() doesn't pad with nulls */
 184         strncpy(name_copy, name, TIPC_MAX_LINK_NAME);
 185         if (name_copy[TIPC_MAX_LINK_NAME - 1] != 0)
 186                 return 0;
 187
 188         /* ensure all component parts of link name are present */
 189         addr_local = name_copy;
 190         if_local = strchr(addr_local, ':');
 191         if (if_local == NULL)
 192                 return 0;
 193         *(if_local++) = 0;
 194         addr_peer = strchr(if_local, '-');
 195         if (addr_peer == NULL)
 196                 return 0;
 197         *(addr_peer++) = 0;
 198         if_local_len = addr_peer - if_local;
 199         if_peer = strchr(addr_peer, ':');
 200         if (if_peer == NULL)
 201                 return 0;
 202         *(if_peer++) = 0;
 203         if_peer_len = strlen(if_peer) + 1;
 204
 205         /* validate component parts of link name */
 206         if ((sscanf(addr_local, "%u.%u.%u%c",
 207                     &z_local, &c_local, &n_local, &dummy) != 3) ||
 208             (sscanf(addr_peer, "%u.%u.%u%c",
 209                     &z_peer, &c_peer, &n_peer, &dummy) != 3) ||
 210             (z_local > 255) || (c_local > 4095) || (n_local > 4095) ||
 211             (z_peer  > 255) || (c_peer  > 4095) || (n_peer  > 4095) ||
 212             (if_local_len <= 1) || (if_local_len > TIPC_MAX_IF_NAME) ||
 213             (if_peer_len  <= 1) || (if_peer_len  > TIPC_MAX_IF_NAME))
 214                 return 0;
 215
 216         /* return link name components, if necessary */
 217         if (name_parts) {
 218                 name_parts->addr_local = tipc_addr(z_local, c_local, n_local);
 219                 strcpy(name_parts->if_local, if_local);
 220                 name_parts->addr_peer = tipc_addr(z_peer, c_peer, n_peer);
 221                 strcpy(name_parts->if_peer, if_peer);
 222         }
 223         return 1;
 224 }
 225
 226 /**
 227  * link_timeout - handle expiration of link timer
 228  * @l_ptr: pointer to link
 229  *
 230  * This routine must not grab "tipc_net_lock" to avoid a potential deadlock conflict
 231  * with tipc_link_delete().  (There is no risk that the node will be deleted by
 232  * another thread because tipc_link_delete() always cancels the link timer before
 233  * tipc_node_delete() is called.)
 234  */
 235 static void link_timeout(struct tipc_link *l_ptr)
 236 {
 237         tipc_node_lock(l_ptr->owner);
 238
 239         /* update counters used in statistical profiling of send traffic */
 240         l_ptr->stats.accu_queue_sz += l_ptr->out_queue_size;
 241         l_ptr->stats.queue_sz_counts++;
 242
 243         if (l_ptr->first_out) {
 244                 struct tipc_msg *msg = buf_msg(l_ptr->first_out);
 245                 u32 length = msg_size(msg);
 246
 247                 if ((msg_user(msg) == MSG_FRAGMENTER) &&
 248                     (msg_type(msg) == FIRST_FRAGMENT)) {
 249                         length = msg_size(msg_get_wrapped(msg));
 250                 }
 251                 if (length) {
 252                         l_ptr->stats.msg_lengths_total += length;
 253                         l_ptr->stats.msg_length_counts++;
 254                         if (length <= 64)
 255                                 l_ptr->stats.msg_length_profile[0]++;
 256                         else if (length <= 256)
 257                                 l_ptr->stats.msg_length_profile[1]++;
 258                         else if (length <= 1024)
 259                                 l_ptr->stats.msg_length_profile[2]++;
 260                         else if (length <= 4096)
 261                                 l_ptr->stats.msg_length_profile[3]++;
 262                         else if (length <= 16384)
 263                                 l_ptr->stats.msg_length_profile[4]++;
 264                         else if (length <= 32768)
 265                                 l_ptr->stats.msg_length_profile[5]++;
 266                         else
 267                                 l_ptr->stats.msg_length_profile[6]++;
 268                 }
 269         }
 270
 271         /* do all other link processing performed on a periodic basis */
 272         link_check_defragm_bufs(l_ptr);
 273
 274         link_state_event(l_ptr, TIMEOUT_EVT);
 275
 276         if (l_ptr->next_out)
 277                 tipc_link_push_queue(l_ptr);
 278
 279         tipc_node_unlock(l_ptr->owner);
 280 }
 281
 282 static void link_set_timer(struct tipc_link *l_ptr, u32 time)
 283 {
 284         k_start_timer(&l_ptr->timer, time);
 285 }
 286
 287 /**
 288  * tipc_link_create - create a new link
 289  * @n_ptr: pointer to associated node
 290  * @b_ptr: pointer to associated bearer
 291  * @media_addr: media address to use when sending messages over link
 292  *
 293  * Returns pointer to link.
 294  */
 295 struct tipc_link *tipc_link_create(struct tipc_node *n_ptr,
 296                               struct tipc_bearer *b_ptr,
 297                               const struct tipc_media_addr *media_addr)
 298 {
 299         struct tipc_link *l_ptr;
 300         struct tipc_msg *msg;
 301         char *if_name;
 302         char addr_string[16];
 303         u32 peer = n_ptr->addr;
 304
 305         if (n_ptr->link_cnt >= 2) {
 306                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 307                 pr_err("Attempt to establish third link to %s\n", addr_string);
 308                 return NULL;
 309         }
 310
 311         if (n_ptr->links[b_ptr->identity]) {
 312                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 313                 pr_err("Attempt to establish second link on <%s> to %s\n",
 314                        b_ptr->name, addr_string);
 315                 return NULL;
 316         }
 317
 318         l_ptr = kzalloc(sizeof(*l_ptr), GFP_ATOMIC);
 319         if (!l_ptr) {
 320                 pr_warn("Link creation failed, no memory\n");
 321                 return NULL;
 322         }
 323
 324         l_ptr->addr = peer;
 325         if_name = strchr(b_ptr->name, ':') + 1;
 326         sprintf(l_ptr->name, "%u.%u.%u:%s-%u.%u.%u:unknown",
 327                 tipc_zone(tipc_own_addr), tipc_cluster(tipc_own_addr),
 328                 tipc_node(tipc_own_addr),
 329                 if_name,
 330                 tipc_zone(peer), tipc_cluster(peer), tipc_node(peer));
 331                 /* note: peer i/f name is updated by reset/activate message */
 332         memcpy(&l_ptr->media_addr, media_addr, sizeof(*media_addr));
 333         l_ptr->owner = n_ptr;
 334         l_ptr->checkpoint = 1;
 335         l_ptr->peer_session = INVALID_SESSION;
 336         l_ptr->b_ptr = b_ptr;
 337         link_set_supervision_props(l_ptr, b_ptr->tolerance);
 338         l_ptr->state = RESET_UNKNOWN;
 339
 340         l_ptr->pmsg = (struct tipc_msg *)&l_ptr->proto_msg;
 341         msg = l_ptr->pmsg;
 342         tipc_msg_init(msg, LINK_PROTOCOL, RESET_MSG, INT_H_SIZE, l_ptr->addr);
 343         msg_set_size(msg, sizeof(l_ptr->proto_msg));
 344         msg_set_session(msg, (tipc_random & 0xffff));
 345         msg_set_bearer_id(msg, b_ptr->identity);
 346         strcpy((char *)msg_data(msg), if_name);
 347
 348         l_ptr->priority = b_ptr->priority;
 349         tipc_link_set_queue_limits(l_ptr, b_ptr->window);
 350
 351         link_init_max_pkt(l_ptr);
 352
 353         l_ptr->next_out_no = 1;
 354         INIT_LIST_HEAD(&l_ptr->waiting_ports);
 355
 356         link_reset_statistics(l_ptr);
 357
 358         tipc_node_attach_link(n_ptr, l_ptr);
 359
 360         k_init_timer(&l_ptr->timer, (Handler)link_timeout, (unsigned long)l_ptr);
 361         list_add_tail(&l_ptr->link_list, &b_ptr->links);
 362         tipc_k_signal((Handler)link_start, (unsigned long)l_ptr);
 363
 364         return l_ptr;
 365 }
 366
 367 /**
 368  * tipc_link_delete - delete a link
 369  * @l_ptr: pointer to link
 370  *
 371  * Note: 'tipc_net_lock' is write_locked, bearer is locked.
 372  * This routine must not grab the node lock until after link timer cancellation
 373  * to avoid a potential deadlock situation.
 374  */
 375 void tipc_link_delete(struct tipc_link *l_ptr)
 376 {
 377         if (!l_ptr) {
 378                 pr_err("Attempt to delete non-existent link\n");
 379                 return;
 380         }
 381
 382         k_cancel_timer(&l_ptr->timer);
 383
 384         tipc_node_lock(l_ptr->owner);
 385         tipc_link_reset(l_ptr);
 386         tipc_node_detach_link(l_ptr->owner, l_ptr);
 387         tipc_link_stop(l_ptr);
 388         list_del_init(&l_ptr->link_list);
 389         tipc_node_unlock(l_ptr->owner);
 390         k_term_timer(&l_ptr->timer);
 391         kfree(l_ptr);
 392 }
 393
 394 static void link_start(struct tipc_link *l_ptr)
 395 {
 396         tipc_node_lock(l_ptr->owner);
 397         link_state_event(l_ptr, STARTING_EVT);
 398         tipc_node_unlock(l_ptr->owner);
 399 }
 400
 401 /**
 402  * link_schedule_port - schedule port for deferred sending
 403  * @l_ptr: pointer to link
 404  * @origport: reference to sending port
 405  * @sz: amount of data to be sent
 406  *
 407  * Schedules port for renewed sending of messages after link congestion
 408  * has abated.
 409  */
 410 static int link_schedule_port(struct tipc_link *l_ptr, u32 origport, u32 sz)
 411 {
 412         struct tipc_port *p_ptr;
 413
 414         spin_lock_bh(&tipc_port_list_lock);
 415         p_ptr = tipc_port_lock(origport);
 416         if (p_ptr) {
 417                 if (!p_ptr->wakeup)
 418                         goto exit;
 419                 if (!list_empty(&p_ptr->wait_list))
 420                         goto exit;
 421                 p_ptr->congested = 1;
 422                 p_ptr->waiting_pkts = 1 + ((sz - 1) / l_ptr->max_pkt);
 423                 list_add_tail(&p_ptr->wait_list, &l_ptr->waiting_ports);
 424                 l_ptr->stats.link_congs++;
 425 exit:
 426                 tipc_port_unlock(p_ptr);
 427         }
 428         spin_unlock_bh(&tipc_port_list_lock);
 429         return -ELINKCONG;
 430 }
 431
 432 void tipc_link_wakeup_ports(struct tipc_link *l_ptr, int all)
 433 {
 434         struct tipc_port *p_ptr;
 435         struct tipc_port *temp_p_ptr;
 436         int win = l_ptr->queue_limit[0] - l_ptr->out_queue_size;
 437
 438         if (all)
 439                 win = 100000;
 440         if (win <= 0)
 441                 return;
 442         if (!spin_trylock_bh(&tipc_port_list_lock))
 443                 return;
 444         if (link_congested(l_ptr))
 445                 goto exit;
 446         list_for_each_entry_safe(p_ptr, temp_p_ptr, &l_ptr->waiting_ports,
 447                                  wait_list) {
 448                 if (win <= 0)
 449                         break;
 450                 list_del_init(&p_ptr->wait_list);
 451                 spin_lock_bh(p_ptr->lock);
 452                 p_ptr->congested = 0;
 453                 p_ptr->wakeup(p_ptr);
 454                 win -= p_ptr->waiting_pkts;
 455                 spin_unlock_bh(p_ptr->lock);
 456         }
 457
 458 exit:
 459         spin_unlock_bh(&tipc_port_list_lock);
 460 }
 461
 462 /**
 463  * link_release_outqueue - purge link's outbound message queue
 464  * @l_ptr: pointer to link
 465  */
 466 static void link_release_outqueue(struct tipc_link *l_ptr)
 467 {
 468         struct sk_buff *buf = l_ptr->first_out;
 469         struct sk_buff *next;
 470
 471         while (buf) {
 472                 next = buf->next;
 473                 kfree_skb(buf);
 474                 buf = next;
 475         }
 476         l_ptr->first_out = NULL;
 477         l_ptr->out_queue_size = 0;
 478 }
 479
 480 /**
 481  * tipc_link_reset_fragments - purge link's inbound message fragments queue
 482  * @l_ptr: pointer to link
 483  */
 484 void tipc_link_reset_fragments(struct tipc_link *l_ptr)
 485 {
 486         struct sk_buff *buf = l_ptr->defragm_buf;
 487         struct sk_buff *next;
 488
 489         while (buf) {
 490                 next = buf->next;
 491                 kfree_skb(buf);
 492                 buf = next;
 493         }
 494         l_ptr->defragm_buf = NULL;
 495 }
 496
 497 /**
 498  * tipc_link_stop - purge all inbound and outbound messages associated with link
 499  * @l_ptr: pointer to link
 500  */
 501 void tipc_link_stop(struct tipc_link *l_ptr)
 502 {
 503         struct sk_buff *buf;
 504         struct sk_buff *next;
 505
 506         buf = l_ptr->oldest_deferred_in;
 507         while (buf) {
 508                 next = buf->next;
 509                 kfree_skb(buf);
 510                 buf = next;
 511         }
 512
 513         buf = l_ptr->first_out;
 514         while (buf) {
 515                 next = buf->next;
 516                 kfree_skb(buf);
 517                 buf = next;
 518         }
 519
 520         tipc_link_reset_fragments(l_ptr);
 521
 522         kfree_skb(l_ptr->proto_msg_queue);
 523         l_ptr->proto_msg_queue = NULL;
 524 }
 525
 526 void tipc_link_reset(struct tipc_link *l_ptr)
 527 {
 528         struct sk_buff *buf;
 529         u32 prev_state = l_ptr->state;
 530         u32 checkpoint = l_ptr->next_in_no;
 531         int was_active_link = tipc_link_is_active(l_ptr);
 532
 533         msg_set_session(l_ptr->pmsg, ((msg_session(l_ptr->pmsg) + 1) & 0xffff));
 534
 535         /* Link is down, accept any session */
 536         l_ptr->peer_session = INVALID_SESSION;
 537
 538         /* Prepare for max packet size negotiation */
 539         link_init_max_pkt(l_ptr);
 540
 541         l_ptr->state = RESET_UNKNOWN;
 542
 543         if ((prev_state == RESET_UNKNOWN) || (prev_state == RESET_RESET))
 544                 return;
 545
 546         tipc_node_link_down(l_ptr->owner, l_ptr);
 547         tipc_bearer_remove_dest(l_ptr->b_ptr, l_ptr->addr);
 548
 549         if (was_active_link && tipc_node_active_links(l_ptr->owner) &&
 550             l_ptr->owner->permit_changeover) {
 551                 l_ptr->reset_checkpoint = checkpoint;
 552                 l_ptr->exp_msg_count = START_CHANGEOVER;
 553         }
 554
 555         /* Clean up all queues: */
 556         link_release_outqueue(l_ptr);
 557         kfree_skb(l_ptr->proto_msg_queue);
 558         l_ptr->proto_msg_queue = NULL;
 559         buf = l_ptr->oldest_deferred_in;
 560         while (buf) {
 561                 struct sk_buff *next = buf->next;
 562                 kfree_skb(buf);
 563                 buf = next;
 564         }
 565         if (!list_empty(&l_ptr->waiting_ports))
 566                 tipc_link_wakeup_ports(l_ptr, 1);
 567
 568         l_ptr->retransm_queue_head = 0;
 569         l_ptr->retransm_queue_size = 0;
 570         l_ptr->last_out = NULL;
 571         l_ptr->first_out = NULL;
 572         l_ptr->next_out = NULL;
 573         l_ptr->unacked_window = 0;
 574         l_ptr->checkpoint = 1;
 575         l_ptr->next_out_no = 1;
 576         l_ptr->deferred_inqueue_sz = 0;
 577         l_ptr->oldest_deferred_in = NULL;
 578         l_ptr->newest_deferred_in = NULL;
 579         l_ptr->fsm_msg_cnt = 0;
 580         l_ptr->stale_count = 0;
 581         link_reset_statistics(l_ptr);
 582 }
 583
 584
 585 static void link_activate(struct tipc_link *l_ptr)
 586 {
 587         l_ptr->next_in_no = l_ptr->stats.recv_info = 1;
 588         tipc_node_link_up(l_ptr->owner, l_ptr);
 589         tipc_bearer_add_dest(l_ptr->b_ptr, l_ptr->addr);
 590 }
 591
 592 /**
 593  * link_state_event - link finite state machine
 594  * @l_ptr: pointer to link
 595  * @event: state machine event to process
 596  */
 597 static void link_state_event(struct tipc_link *l_ptr, unsigned int event)
 598 {
 599         struct tipc_link *other;
 600         u32 cont_intv = l_ptr->continuity_interval;
 601
 602         if (!l_ptr->started && (event != STARTING_EVT))
 603                 return;         /* Not yet. */
 604
 605         if (link_blocked(l_ptr)) {
 606                 if (event == TIMEOUT_EVT)
 607                         link_set_timer(l_ptr, cont_intv);
 608                 return;   /* Changeover going on */
 609         }
 610
 611         switch (l_ptr->state) {
 612         case WORKING_WORKING:
 613                 switch (event) {
 614                 case TRAFFIC_MSG_EVT:
 615                 case ACTIVATE_MSG:
 616                         break;
 617                 case TIMEOUT_EVT:
 618                         if (l_ptr->next_in_no != l_ptr->checkpoint) {
 619                                 l_ptr->checkpoint = l_ptr->next_in_no;
 620                                 if (tipc_bclink_acks_missing(l_ptr->owner)) {
 621                                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
 622                                                                  0, 0, 0, 0, 0);
 623                                         l_ptr->fsm_msg_cnt++;
 624                                 } else if (l_ptr->max_pkt < l_ptr->max_pkt_target) {
 625                                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
 626                                                                  1, 0, 0, 0, 0);
 627                                         l_ptr->fsm_msg_cnt++;
 628                                 }
 629                                 link_set_timer(l_ptr, cont_intv);
 630                                 break;
 631                         }
 632                         l_ptr->state = WORKING_UNKNOWN;
 633                         l_ptr->fsm_msg_cnt = 0;
 634                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
 635                         l_ptr->fsm_msg_cnt++;
 636                         link_set_timer(l_ptr, cont_intv / 4);
 637                         break;
 638                 case RESET_MSG:
 639                         pr_info("%s<%s>, requested by peer\n", link_rst_msg,
 640                                 l_ptr->name);
 641                         tipc_link_reset(l_ptr);
 642                         l_ptr->state = RESET_RESET;
 643                         l_ptr->fsm_msg_cnt = 0;
 644                         tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
 645                         l_ptr->fsm_msg_cnt++;
 646                         link_set_timer(l_ptr, cont_intv);
 647                         break;
 648                 default:
 649                         pr_err("%s%u in WW state\n", link_unk_evt, event);
 650                 }
 651                 break;
 652         case WORKING_UNKNOWN:
 653                 switch (event) {
 654                 case TRAFFIC_MSG_EVT:
 655                 case ACTIVATE_MSG:
 656                         l_ptr->state = WORKING_WORKING;
 657                         l_ptr->fsm_msg_cnt = 0;
 658                         link_set_timer(l_ptr, cont_intv);
 659                         break;
 660                 case RESET_MSG:
 661                         pr_info("%s<%s>, requested by peer while probing\n",
 662                                 link_rst_msg, l_ptr->name);
 663                         tipc_link_reset(l_ptr);
 664                         l_ptr->state = RESET_RESET;
 665                         l_ptr->fsm_msg_cnt = 0;
 666                         tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
 667                         l_ptr->fsm_msg_cnt++;
 668                         link_set_timer(l_ptr, cont_intv);
 669                         break;
 670                 case TIMEOUT_EVT:
 671                         if (l_ptr->next_in_no != l_ptr->checkpoint) {
 672                                 l_ptr->state = WORKING_WORKING;
 673                                 l_ptr->fsm_msg_cnt = 0;
 674                                 l_ptr->checkpoint = l_ptr->next_in_no;
 675                                 if (tipc_bclink_acks_missing(l_ptr->owner)) {
 676                                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
 677                                                                  0, 0, 0, 0, 0);
 678                                         l_ptr->fsm_msg_cnt++;
 679                                 }
 680                                 link_set_timer(l_ptr, cont_intv);
 681                         } else if (l_ptr->fsm_msg_cnt < l_ptr->abort_limit) {
 682                                 tipc_link_send_proto_msg(l_ptr, STATE_MSG,
 683                                                          1, 0, 0, 0, 0);
 684                                 l_ptr->fsm_msg_cnt++;
 685                                 link_set_timer(l_ptr, cont_intv / 4);
 686                         } else {        /* Link has failed */
 687                                 pr_warn("%s<%s>, peer not responding\n",
 688                                         link_rst_msg, l_ptr->name);
 689                                 tipc_link_reset(l_ptr);
 690                                 l_ptr->state = RESET_UNKNOWN;
 691                                 l_ptr->fsm_msg_cnt = 0;
 692                                 tipc_link_send_proto_msg(l_ptr, RESET_MSG,
 693                                                          0, 0, 0, 0, 0);
 694                                 l_ptr->fsm_msg_cnt++;
 695                                 link_set_timer(l_ptr, cont_intv);
 696                         }
 697                         break;
 698                 default:
 699                         pr_err("%s%u in WU state\n", link_unk_evt, event);
 700                 }
 701                 break;
 702         case RESET_UNKNOWN:
 703                 switch (event) {
 704                 case TRAFFIC_MSG_EVT:
 705                         break;
 706                 case ACTIVATE_MSG:
 707                         other = l_ptr->owner->active_links[0];
 708                         if (other && link_working_unknown(other))
 709                                 break;
 710                         l_ptr->state = WORKING_WORKING;
 711                         l_ptr->fsm_msg_cnt = 0;
 712                         link_activate(l_ptr);
 713                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
 714                         l_ptr->fsm_msg_cnt++;
 715                         link_set_timer(l_ptr, cont_intv);
 716                         break;
 717                 case RESET_MSG:
 718                         l_ptr->state = RESET_RESET;
 719                         l_ptr->fsm_msg_cnt = 0;
 720                         tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 1, 0, 0, 0, 0);
 721                         l_ptr->fsm_msg_cnt++;
 722                         link_set_timer(l_ptr, cont_intv);
 723                         break;
 724                 case STARTING_EVT:
 725                         l_ptr->started = 1;
 726                         /* fall through */
 727                 case TIMEOUT_EVT:
 728                         tipc_link_send_proto_msg(l_ptr, RESET_MSG, 0, 0, 0, 0, 0);
 729                         l_ptr->fsm_msg_cnt++;
 730                         link_set_timer(l_ptr, cont_intv);
 731                         break;
 732                 default:
 733                         pr_err("%s%u in RU state\n", link_unk_evt, event);
 734                 }
 735                 break;
 736         case RESET_RESET:
 737                 switch (event) {
 738                 case TRAFFIC_MSG_EVT:
 739                 case ACTIVATE_MSG:
 740                         other = l_ptr->owner->active_links[0];
 741                         if (other && link_working_unknown(other))
 742                                 break;
 743                         l_ptr->state = WORKING_WORKING;
 744                         l_ptr->fsm_msg_cnt = 0;
 745                         link_activate(l_ptr);
 746                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
 747                         l_ptr->fsm_msg_cnt++;
 748                         link_set_timer(l_ptr, cont_intv);
 749                         break;
 750                 case RESET_MSG:
 751                         break;
 752                 case TIMEOUT_EVT:
 753                         tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
 754                         l_ptr->fsm_msg_cnt++;
 755                         link_set_timer(l_ptr, cont_intv);
 756                         break;
 757                 default:
 758                         pr_err("%s%u in RR state\n", link_unk_evt, event);
 759                 }
 760                 break;
 761         default:
 762                 pr_err("Unknown link state %u/%u\n", l_ptr->state, event);
 763         }
 764 }
 765
 766 /*
 767  * link_bundle_buf(): Append contents of a buffer to
 768  * the tail of an existing one.
 769  */
 770 static int link_bundle_buf(struct tipc_link *l_ptr,
 771                            struct sk_buff *bundler,
 772                            struct sk_buff *buf)
 773 {
 774         struct tipc_msg *bundler_msg = buf_msg(bundler);
 775         struct tipc_msg *msg = buf_msg(buf);
 776         u32 size = msg_size(msg);
 777         u32 bundle_size = msg_size(bundler_msg);
 778         u32 to_pos = align(bundle_size);
 779         u32 pad = to_pos - bundle_size;
 780
 781         if (msg_user(bundler_msg) != MSG_BUNDLER)
 782                 return 0;
 783         if (msg_type(bundler_msg) != OPEN_MSG)
 784                 return 0;
 785         if (skb_tailroom(bundler) < (pad + size))
 786                 return 0;
 787         if (l_ptr->max_pkt < (to_pos + size))
 788                 return 0;
 789
 790         skb_put(bundler, pad + size);
 791         skb_copy_to_linear_data_offset(bundler, to_pos, buf->data, size);
 792         msg_set_size(bundler_msg, to_pos + size);
 793         msg_set_msgcnt(bundler_msg, msg_msgcnt(bundler_msg) + 1);
 794         kfree_skb(buf);
 795         l_ptr->stats.sent_bundled++;
 796         return 1;
 797 }
 798
 799 static void link_add_to_outqueue(struct tipc_link *l_ptr,
 800                                  struct sk_buff *buf,
 801                                  struct tipc_msg *msg)
 802 {
 803         u32 ack = mod(l_ptr->next_in_no - 1);
 804         u32 seqno = mod(l_ptr->next_out_no++);
 805
 806         msg_set_word(msg, 2, ((ack << 16) | seqno));
 807         msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
 808         buf->next = NULL;
 809         if (l_ptr->first_out) {
 810                 l_ptr->last_out->next = buf;
 811                 l_ptr->last_out = buf;
 812         } else
 813                 l_ptr->first_out = l_ptr->last_out = buf;
 814
 815         l_ptr->out_queue_size++;
 816         if (l_ptr->out_queue_size > l_ptr->stats.max_queue_sz)
 817                 l_ptr->stats.max_queue_sz = l_ptr->out_queue_size;
 818 }
 819
 820 static void link_add_chain_to_outqueue(struct tipc_link *l_ptr,
 821                                        struct sk_buff *buf_chain,
 822                                        u32 long_msgno)
 823 {
 824         struct sk_buff *buf;
 825         struct tipc_msg *msg;
 826
 827         if (!l_ptr->next_out)
 828                 l_ptr->next_out = buf_chain;
 829         while (buf_chain) {
 830                 buf = buf_chain;
 831                 buf_chain = buf_chain->next;
 832
 833                 msg = buf_msg(buf);
 834                 msg_set_long_msgno(msg, long_msgno);
 835                 link_add_to_outqueue(l_ptr, buf, msg);
 836         }
 837 }
 838
 839 /*
 840  * tipc_link_send_buf() is the 'full path' for messages, called from
 841  * inside TIPC when the 'fast path' in tipc_send_buf
 842  * has failed, and from link_send()
 843  */
 844 int tipc_link_send_buf(struct tipc_link *l_ptr, struct sk_buff *buf)
 845 {
 846         struct tipc_msg *msg = buf_msg(buf);
 847         u32 size = msg_size(msg);
 848         u32 dsz = msg_data_sz(msg);
 849         u32 queue_size = l_ptr->out_queue_size;
 850         u32 imp = tipc_msg_tot_importance(msg);
 851         u32 queue_limit = l_ptr->queue_limit[imp];
 852         u32 max_packet = l_ptr->max_pkt;
 853
 854         /* Match msg importance against queue limits: */
 855         if (unlikely(queue_size >= queue_limit)) {
 856                 if (imp <= TIPC_CRITICAL_IMPORTANCE) {
 857                         link_schedule_port(l_ptr, msg_origport(msg), size);
 858                         kfree_skb(buf);
 859                         return -ELINKCONG;
 860                 }
 861                 kfree_skb(buf);
 862                 if (imp > CONN_MANAGER) {
 863                         pr_warn("%s<%s>, send queue full", link_rst_msg,
 864                                 l_ptr->name);
 865                         tipc_link_reset(l_ptr);
 866                 }
 867                 return dsz;
 868         }
 869
 870         /* Fragmentation needed ? */
 871         if (size > max_packet)
 872                 return link_send_long_buf(l_ptr, buf);
 873
 874         /* Packet can be queued or sent. */
 875         if (likely(!tipc_bearer_blocked(l_ptr->b_ptr) &&
 876                    !link_congested(l_ptr))) {
 877                 link_add_to_outqueue(l_ptr, buf, msg);
 878
 879                 tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr);
 880                 l_ptr->unacked_window = 0;
 881                 return dsz;
 882         }
 883         /* Congestion: can message be bundled ? */
 884         if ((msg_user(msg) != CHANGEOVER_PROTOCOL) &&
 885             (msg_user(msg) != MSG_FRAGMENTER)) {
 886
 887                 /* Try adding message to an existing bundle */
 888                 if (l_ptr->next_out &&
 889                     link_bundle_buf(l_ptr, l_ptr->last_out, buf))
 890                         return dsz;
 891
 892                 /* Try creating a new bundle */
 893                 if (size <= max_packet * 2 / 3) {
 894                         struct sk_buff *bundler = tipc_buf_acquire(max_packet);
 895                         struct tipc_msg bundler_hdr;
 896
 897                         if (bundler) {
 898                                 tipc_msg_init(&bundler_hdr, MSG_BUNDLER, OPEN_MSG,
 899                                          INT_H_SIZE, l_ptr->addr);
 900                                 skb_copy_to_linear_data(bundler, &bundler_hdr,
 901                                                         INT_H_SIZE);
 902                                 skb_trim(bundler, INT_H_SIZE);
 903                                 link_bundle_buf(l_ptr, bundler, buf);
 904                                 buf = bundler;
 905                                 msg = buf_msg(buf);
 906                                 l_ptr->stats.sent_bundles++;
 907                         }
 908                 }
 909         }
 910         if (!l_ptr->next_out)
 911                 l_ptr->next_out = buf;
 912         link_add_to_outqueue(l_ptr, buf, msg);
 913         return dsz;
 914 }
 915
 916 /*
 917  * tipc_link_send(): same as tipc_link_send_buf(), but the link to use has
 918  * not been selected yet, and the the owner node is not locked
 919  * Called by TIPC internal users, e.g. the name distributor
 920  */
 921 int tipc_link_send(struct sk_buff *buf, u32 dest, u32 selector)
 922 {
 923         struct tipc_link *l_ptr;
 924         struct tipc_node *n_ptr;
 925         int res = -ELINKCONG;
 926
 927         read_lock_bh(&tipc_net_lock);
 928         n_ptr = tipc_node_find(dest);
 929         if (n_ptr) {
 930                 tipc_node_lock(n_ptr);
 931                 l_ptr = n_ptr->active_links[selector & 1];
 932                 if (l_ptr)
 933                         res = tipc_link_send_buf(l_ptr, buf);
 934                 else
 935                         kfree_skb(buf);
 936                 tipc_node_unlock(n_ptr);
 937         } else {
 938                 kfree_skb(buf);
 939         }
 940         read_unlock_bh(&tipc_net_lock);
 941         return res;
 942 }
 943
 944 /**
 945  * tipc_link_send_names - send name table entries to new neighbor
 946  *
 947  * Send routine for bulk delivery of name table messages when contact
 948  * with a new neighbor occurs. No link congestion checking is performed
 949  * because name table messages *must* be delivered. The messages must be
 950  * small enough not to require fragmentation.
 951  * Called without any locks held.
 952  */
 953 void tipc_link_send_names(struct list_head *message_list, u32 dest)
 954 {
 955         struct tipc_node *n_ptr;
 956         struct tipc_link *l_ptr;
 957         struct sk_buff *buf;
 958         struct sk_buff *temp_buf;
 959
 960         if (list_empty(message_list))
 961                 return;
 962
 963         read_lock_bh(&tipc_net_lock);
 964         n_ptr = tipc_node_find(dest);
 965         if (n_ptr) {
 966                 tipc_node_lock(n_ptr);
 967                 l_ptr = n_ptr->active_links[0];
 968                 if (l_ptr) {
 969                         /* convert circular list to linear list */
 970                         ((struct sk_buff *)message_list->prev)->next = NULL;
 971                         link_add_chain_to_outqueue(l_ptr,
 972                                 (struct sk_buff *)message_list->next, 0);
 973                         tipc_link_push_queue(l_ptr);
 974                         INIT_LIST_HEAD(message_list);
 975                 }
 976                 tipc_node_unlock(n_ptr);
 977         }
 978         read_unlock_bh(&tipc_net_lock);
 979
 980         /* discard the messages if they couldn't be sent */
 981         list_for_each_safe(buf, temp_buf, ((struct sk_buff *)message_list)) {
 982                 list_del((struct list_head *)buf);
 983                 kfree_skb(buf);
 984         }
 985 }
 986
 987 /*
 988  * link_send_buf_fast: Entry for data messages where the
 989  * destination link is known and the header is complete,
 990  * inclusive total message length. Very time critical.
 991  * Link is locked. Returns user data length.
 992  */
 993 static int link_send_buf_fast(struct tipc_link *l_ptr, struct sk_buff *buf,
 994                               u32 *used_max_pkt)
 995 {
 996         struct tipc_msg *msg = buf_msg(buf);
 997         int res = msg_data_sz(msg);
 998
 999         if (likely(!link_congested(l_ptr))) {
1000                 if (likely(msg_size(msg) <= l_ptr->max_pkt)) {
1001                         if (likely(!tipc_bearer_blocked(l_ptr->b_ptr))) {
1002                                 link_add_to_outqueue(l_ptr, buf, msg);
1003                                 tipc_bearer_send(l_ptr->b_ptr, buf,
1004                                                  &l_ptr->media_addr);
1005                                 l_ptr->unacked_window = 0;
1006                                 return res;
1007                         }
1008                 } else
1009                         *used_max_pkt = l_ptr->max_pkt;
1010         }
1011         return tipc_link_send_buf(l_ptr, buf);  /* All other cases */
1012 }
1013
1014 /*
1015  * tipc_send_buf_fast: Entry for data messages where the
1016  * destination node is known and the header is complete,
1017  * inclusive total message length.
1018  * Returns user data length.
1019  */
1020 int tipc_send_buf_fast(struct sk_buff *buf, u32 destnode)
1021 {
1022         struct tipc_link *l_ptr;
1023         struct tipc_node *n_ptr;
1024         int res;
1025         u32 selector = msg_origport(buf_msg(buf)) & 1;
1026         u32 dummy;
1027
1028         read_lock_bh(&tipc_net_lock);
1029         n_ptr = tipc_node_find(destnode);
1030         if (likely(n_ptr)) {
1031                 tipc_node_lock(n_ptr);
1032                 l_ptr = n_ptr->active_links[selector];
1033                 if (likely(l_ptr)) {
1034                         res = link_send_buf_fast(l_ptr, buf, &dummy);
1035                         tipc_node_unlock(n_ptr);
1036                         read_unlock_bh(&tipc_net_lock);
1037                         return res;
1038                 }
1039                 tipc_node_unlock(n_ptr);
1040         }
1041         read_unlock_bh(&tipc_net_lock);
1042         res = msg_data_sz(buf_msg(buf));
1043         tipc_reject_msg(buf, TIPC_ERR_NO_NODE);
1044         return res;
1045 }
1046
1047
1048 /*
1049  * tipc_link_send_sections_fast: Entry for messages where the
1050  * destination processor is known and the header is complete,
1051  * except for total message length.
1052  * Returns user data length or errno.
1053  */
1054 int tipc_link_send_sections_fast(struct tipc_port *sender,
1055                                  struct iovec const *msg_sect,
1056                                  const u32 num_sect,
1057                                  unsigned int total_len,
1058                                  u32 destaddr)
1059 {
1060         struct tipc_msg *hdr = &sender->phdr;
1061         struct tipc_link *l_ptr;
1062         struct sk_buff *buf;
1063         struct tipc_node *node;
1064         int res;
1065         u32 selector = msg_origport(hdr) & 1;
1066
1067 again:
1068         /*
1069          * Try building message using port's max_pkt hint.
1070          * (Must not hold any locks while building message.)
1071          */
1072         res = tipc_msg_build(hdr, msg_sect, num_sect, total_len,
1073                              sender->max_pkt, !sender->user_port, &buf);
1074
1075         read_lock_bh(&tipc_net_lock);
1076         node = tipc_node_find(destaddr);
1077         if (likely(node)) {
1078                 tipc_node_lock(node);
1079                 l_ptr = node->active_links[selector];
1080                 if (likely(l_ptr)) {
1081                         if (likely(buf)) {
1082                                 res = link_send_buf_fast(l_ptr, buf,
1083                                                          &sender->max_pkt);
1084 exit:
1085                                 tipc_node_unlock(node);
1086                                 read_unlock_bh(&tipc_net_lock);
1087                                 return res;
1088                         }
1089
1090                         /* Exit if build request was invalid */
1091                         if (unlikely(res < 0))
1092                                 goto exit;
1093
1094                         /* Exit if link (or bearer) is congested */
1095                         if (link_congested(l_ptr) ||
1096                             tipc_bearer_blocked(l_ptr->b_ptr)) {
1097                                 res = link_schedule_port(l_ptr,
1098                                                          sender->ref, res);
1099                                 goto exit;
1100                         }
1101
1102                         /*
1103                          * Message size exceeds max_pkt hint; update hint,
1104                          * then re-try fast path or fragment the message
1105                          */
1106                         sender->max_pkt = l_ptr->max_pkt;
1107                         tipc_node_unlock(node);
1108                         read_unlock_bh(&tipc_net_lock);
1109
1110
1111                         if ((msg_hdr_sz(hdr) + res) <= sender->max_pkt)
1112                                 goto again;
1113
1114                         return link_send_sections_long(sender, msg_sect,
1115                                                        num_sect, total_len,
1116                                                        destaddr);
1117                 }
1118                 tipc_node_unlock(node);
1119         }
1120         read_unlock_bh(&tipc_net_lock);
1121
1122         /* Couldn't find a link to the destination node */
1123         if (buf)
1124                 return tipc_reject_msg(buf, TIPC_ERR_NO_NODE);
1125         if (res >= 0)
1126                 return tipc_port_reject_sections(sender, hdr, msg_sect, num_sect,
1127                                                  total_len, TIPC_ERR_NO_NODE);
1128         return res;
1129 }
1130
1131 /*
1132  * link_send_sections_long(): Entry for long messages where the
1133  * destination node is known and the header is complete,
1134  * inclusive total message length.
1135  * Link and bearer congestion status have been checked to be ok,
1136  * and are ignored if they change.
1137  *
1138  * Note that fragments do not use the full link MTU so that they won't have
1139  * to undergo refragmentation if link changeover causes them to be sent
1140  * over another link with an additional tunnel header added as prefix.
1141  * (Refragmentation will still occur if the other link has a smaller MTU.)
1142  *
1143  * Returns user data length or errno.
1144  */
1145 static int link_send_sections_long(struct tipc_port *sender,
1146                                    struct iovec const *msg_sect,
1147                                    u32 num_sect,
1148                                    unsigned int total_len,
1149                                    u32 destaddr)
1150 {
1151         struct tipc_link *l_ptr;
1152         struct tipc_node *node;
1153         struct tipc_msg *hdr = &sender->phdr;
1154         u32 dsz = total_len;
1155         u32 max_pkt, fragm_sz, rest;
1156         struct tipc_msg fragm_hdr;
1157         struct sk_buff *buf, *buf_chain, *prev;
1158         u32 fragm_crs, fragm_rest, hsz, sect_rest;
1159         const unchar *sect_crs;
1160         int curr_sect;
1161         u32 fragm_no;
1162
1163 again:
1164         fragm_no = 1;
1165         max_pkt = sender->max_pkt - INT_H_SIZE;
1166                 /* leave room for tunnel header in case of link changeover */
1167         fragm_sz = max_pkt - INT_H_SIZE;
1168                 /* leave room for fragmentation header in each fragment */
1169         rest = dsz;
1170         fragm_crs = 0;
1171         fragm_rest = 0;
1172         sect_rest = 0;
1173         sect_crs = NULL;
1174         curr_sect = -1;
1175
1176         /* Prepare reusable fragment header */
1177         tipc_msg_init(&fragm_hdr, MSG_FRAGMENTER, FIRST_FRAGMENT,
1178                  INT_H_SIZE, msg_destnode(hdr));
1179         msg_set_size(&fragm_hdr, max_pkt);
1180         msg_set_fragm_no(&fragm_hdr, 1);
1181
1182         /* Prepare header of first fragment */
1183         buf_chain = buf = tipc_buf_acquire(max_pkt);
1184         if (!buf)
1185                 return -ENOMEM;
1186         buf->next = NULL;
1187         skb_copy_to_linear_data(buf, &fragm_hdr, INT_H_SIZE);
1188         hsz = msg_hdr_sz(hdr);
1189         skb_copy_to_linear_data_offset(buf, INT_H_SIZE, hdr, hsz);
1190
1191         /* Chop up message */
1192         fragm_crs = INT_H_SIZE + hsz;
1193         fragm_rest = fragm_sz - hsz;
1194
1195         do {            /* For all sections */
1196                 u32 sz;
1197
1198                 if (!sect_rest) {
1199                         sect_rest = msg_sect[++curr_sect].iov_len;
1200                         sect_crs = (const unchar *)msg_sect[curr_sect].iov_base;
1201                 }
1202
1203                 if (sect_rest < fragm_rest)
1204                         sz = sect_rest;
1205                 else
1206                         sz = fragm_rest;
1207
1208                 if (likely(!sender->user_port)) {
1209                         if (copy_from_user(buf->data + fragm_crs, sect_crs, sz)) {
1210 error:
1211                                 for (; buf_chain; buf_chain = buf) {
1212                                         buf = buf_chain->next;
1213                                         kfree_skb(buf_chain);
1214                                 }
1215                                 return -EFAULT;
1216                         }
1217                 } else
1218                         skb_copy_to_linear_data_offset(buf, fragm_crs,
1219                                                        sect_crs, sz);
1220                 sect_crs += sz;
1221                 sect_rest -= sz;
1222                 fragm_crs += sz;
1223                 fragm_rest -= sz;
1224                 rest -= sz;
1225
1226                 if (!fragm_rest && rest) {
1227
1228                         /* Initiate new fragment: */
1229                         if (rest <= fragm_sz) {
1230                                 fragm_sz = rest;
1231                                 msg_set_type(&fragm_hdr, LAST_FRAGMENT);
1232                         } else {
1233                                 msg_set_type(&fragm_hdr, FRAGMENT);
1234                         }
1235                         msg_set_size(&fragm_hdr, fragm_sz + INT_H_SIZE);
1236                         msg_set_fragm_no(&fragm_hdr, ++fragm_no);
1237                         prev = buf;
1238                         buf = tipc_buf_acquire(fragm_sz + INT_H_SIZE);
1239                         if (!buf)
1240                                 goto error;
1241
1242                         buf->next = NULL;
1243                         prev->next = buf;
1244                         skb_copy_to_linear_data(buf, &fragm_hdr, INT_H_SIZE);
1245                         fragm_crs = INT_H_SIZE;
1246                         fragm_rest = fragm_sz;
1247                 }
1248         } while (rest > 0);
1249
1250         /*
1251          * Now we have a buffer chain. Select a link and check
1252          * that packet size is still OK
1253          */
1254         node = tipc_node_find(destaddr);
1255         if (likely(node)) {
1256                 tipc_node_lock(node);
1257                 l_ptr = node->active_links[sender->ref & 1];
1258                 if (!l_ptr) {
1259                         tipc_node_unlock(node);
1260                         goto reject;
1261                 }
1262                 if (l_ptr->max_pkt < max_pkt) {
1263                         sender->max_pkt = l_ptr->max_pkt;
1264                         tipc_node_unlock(node);
1265                         for (; buf_chain; buf_chain = buf) {
1266                                 buf = buf_chain->next;
1267                                 kfree_skb(buf_chain);
1268                         }
1269                         goto again;
1270                 }
1271         } else {
1272 reject:
1273                 for (; buf_chain; buf_chain = buf) {
1274                         buf = buf_chain->next;
1275                         kfree_skb(buf_chain);
1276                 }
1277                 return tipc_port_reject_sections(sender, hdr, msg_sect, num_sect,
1278                                                  total_len, TIPC_ERR_NO_NODE);
1279         }
1280
1281         /* Append chain of fragments to send queue & send them */
1282         l_ptr->long_msg_seq_no++;
1283         link_add_chain_to_outqueue(l_ptr, buf_chain, l_ptr->long_msg_seq_no);
1284         l_ptr->stats.sent_fragments += fragm_no;
1285         l_ptr->stats.sent_fragmented++;
1286         tipc_link_push_queue(l_ptr);
1287         tipc_node_unlock(node);
1288         return dsz;
1289 }
1290
1291 /*
1292  * tipc_link_push_packet: Push one unsent packet to the media
1293  */
1294 u32 tipc_link_push_packet(struct tipc_link *l_ptr)
1295 {
1296         struct sk_buff *buf = l_ptr->first_out;
1297         u32 r_q_size = l_ptr->retransm_queue_size;
1298         u32 r_q_head = l_ptr->retransm_queue_head;
1299
1300         /* Step to position where retransmission failed, if any,    */
1301         /* consider that buffers may have been released in meantime */
1302         if (r_q_size && buf) {
1303                 u32 last = lesser(mod(r_q_head + r_q_size),
1304                                   link_last_sent(l_ptr));
1305                 u32 first = buf_seqno(buf);
1306
1307                 while (buf && less(first, r_q_head)) {
1308                         first = mod(first + 1);
1309                         buf = buf->next;
1310                 }
1311                 l_ptr->retransm_queue_head = r_q_head = first;
1312                 l_ptr->retransm_queue_size = r_q_size = mod(last - first);
1313         }
1314
1315         /* Continue retransmission now, if there is anything: */
1316         if (r_q_size && buf) {
1317                 msg_set_ack(buf_msg(buf), mod(l_ptr->next_in_no - 1));
1318                 msg_set_bcast_ack(buf_msg(buf), l_ptr->owner->bclink.last_in);
1319                 tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr);
1320                 l_ptr->retransm_queue_head = mod(++r_q_head);
1321                 l_ptr->retransm_queue_size = --r_q_size;
1322                 l_ptr->stats.retransmitted++;
1323                 return 0;
1324         }
1325
1326         /* Send deferred protocol message, if any: */
1327         buf = l_ptr->proto_msg_queue;
1328         if (buf) {
1329                 msg_set_ack(buf_msg(buf), mod(l_ptr->next_in_no - 1));
1330                 msg_set_bcast_ack(buf_msg(buf), l_ptr->owner->bclink.last_in);
1331                 tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr);
1332                 l_ptr->unacked_window = 0;
1333                 kfree_skb(buf);
1334                 l_ptr->proto_msg_queue = NULL;
1335                 return 0;
1336         }
1337
1338         /* Send one deferred data message, if send window not full: */
1339         buf = l_ptr->next_out;
1340         if (buf) {
1341                 struct tipc_msg *msg = buf_msg(buf);
1342                 u32 next = msg_seqno(msg);
1343                 u32 first = buf_seqno(l_ptr->first_out);
1344
1345                 if (mod(next - first) < l_ptr->queue_limit[0]) {
1346                         msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1347                         msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1348                         tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr);
1349                         if (msg_user(msg) == MSG_BUNDLER)
1350                                 msg_set_type(msg, CLOSED_MSG);
1351                         l_ptr->next_out = buf->next;
1352                         return 0;
1353                 }
1354         }
1355         return 1;
1356 }
1357
1358 /*
1359  * push_queue(): push out the unsent messages of a link where
1360  *               congestion has abated. Node is locked
1361  */
1362 void tipc_link_push_queue(struct tipc_link *l_ptr)
1363 {
1364         u32 res;
1365
1366         if (tipc_bearer_blocked(l_ptr->b_ptr))
1367                 return;
1368
1369         do {
1370                 res = tipc_link_push_packet(l_ptr);
1371         } while (!res);
1372 }
1373
1374 static void link_reset_all(unsigned long addr)
1375 {
1376         struct tipc_node *n_ptr;
1377         char addr_string[16];
1378         u32 i;
1379
1380         read_lock_bh(&tipc_net_lock);
1381         n_ptr = tipc_node_find((u32)addr);
1382         if (!n_ptr) {
1383                 read_unlock_bh(&tipc_net_lock);
1384                 return; /* node no longer exists */
1385         }
1386
1387         tipc_node_lock(n_ptr);
1388
1389         pr_warn("Resetting all links to %s\n",
1390                 tipc_addr_string_fill(addr_string, n_ptr->addr));
1391
1392         for (i = 0; i < MAX_BEARERS; i++) {
1393                 if (n_ptr->links[i]) {
1394                         link_print(n_ptr->links[i], "Resetting link\n");
1395                         tipc_link_reset(n_ptr->links[i]);
1396                 }
1397         }
1398
1399         tipc_node_unlock(n_ptr);
1400         read_unlock_bh(&tipc_net_lock);
1401 }
1402
1403 static void link_retransmit_failure(struct tipc_link *l_ptr,
1404                                         struct sk_buff *buf)
1405 {
1406         struct tipc_msg *msg = buf_msg(buf);
1407
1408         pr_warn("Retransmission failure on link <%s>\n", l_ptr->name);
1409
1410         if (l_ptr->addr) {
1411                 /* Handle failure on standard link */
1412                 link_print(l_ptr, "Resetting link\n");
1413                 tipc_link_reset(l_ptr);
1414
1415         } else {
1416                 /* Handle failure on broadcast link */
1417                 struct tipc_node *n_ptr;
1418                 char addr_string[16];
1419
1420                 pr_info("Msg seq number: %u,  ", msg_seqno(msg));
1421                 pr_cont("Outstanding acks: %lu\n",
1422                         (unsigned long) TIPC_SKB_CB(buf)->handle);
1423
1424                 n_ptr = tipc_bclink_retransmit_to();
1425                 tipc_node_lock(n_ptr);
1426
1427                 tipc_addr_string_fill(addr_string, n_ptr->addr);
1428                 pr_info("Broadcast link info for %s\n", addr_string);
1429                 pr_info("Reception permitted: %d,  Acked: %u\n",
1430                         n_ptr->bclink.recv_permitted,
1431                         n_ptr->bclink.acked);
1432                 pr_info("Last in: %u,  Oos state: %u,  Last sent: %u\n",
1433                         n_ptr->bclink.last_in,
1434                         n_ptr->bclink.oos_state,
1435                         n_ptr->bclink.last_sent);
1436
1437                 tipc_k_signal((Handler)link_reset_all, (unsigned long)n_ptr->addr);
1438
1439                 tipc_node_unlock(n_ptr);
1440
1441                 l_ptr->stale_count = 0;
1442         }
1443 }
1444
1445 void tipc_link_retransmit(struct tipc_link *l_ptr, struct sk_buff *buf,
1446                           u32 retransmits)
1447 {
1448         struct tipc_msg *msg;
1449
1450         if (!buf)
1451                 return;
1452
1453         msg = buf_msg(buf);
1454
1455         if (tipc_bearer_blocked(l_ptr->b_ptr)) {
1456                 if (l_ptr->retransm_queue_size == 0) {
1457                         l_ptr->retransm_queue_head = msg_seqno(msg);
1458                         l_ptr->retransm_queue_size = retransmits;
1459                 } else {
1460                         pr_err("Unexpected retransmit on link %s (qsize=%d)\n",
1461                                l_ptr->name, l_ptr->retransm_queue_size);
1462                 }
1463                 return;
1464         } else {
1465                 /* Detect repeated retransmit failures on unblocked bearer */
1466                 if (l_ptr->last_retransmitted == msg_seqno(msg)) {
1467                         if (++l_ptr->stale_count > 100) {
1468                                 link_retransmit_failure(l_ptr, buf);
1469                                 return;
1470                         }
1471                 } else {
1472                         l_ptr->last_retransmitted = msg_seqno(msg);
1473                         l_ptr->stale_count = 1;
1474                 }
1475         }
1476
1477         while (retransmits && (buf != l_ptr->next_out) && buf) {
1478                 msg = buf_msg(buf);
1479                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1480                 msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1481                 tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr);
1482                 buf = buf->next;
1483                 retransmits--;
1484                 l_ptr->stats.retransmitted++;
1485         }
1486
1487         l_ptr->retransm_queue_head = l_ptr->retransm_queue_size = 0;
1488 }
1489
1490 /**
1491  * link_insert_deferred_queue - insert deferred messages back into receive chain
1492  */
1493 static struct sk_buff *link_insert_deferred_queue(struct tipc_link *l_ptr,
1494                                                   struct sk_buff *buf)
1495 {
1496         u32 seq_no;
1497
1498         if (l_ptr->oldest_deferred_in == NULL)
1499                 return buf;
1500
1501         seq_no = buf_seqno(l_ptr->oldest_deferred_in);
1502         if (seq_no == mod(l_ptr->next_in_no)) {
1503                 l_ptr->newest_deferred_in->next = buf;
1504                 buf = l_ptr->oldest_deferred_in;
1505                 l_ptr->oldest_deferred_in = NULL;
1506                 l_ptr->deferred_inqueue_sz = 0;
1507         }
1508         return buf;
1509 }
1510
1511 /**
1512  * link_recv_buf_validate - validate basic format of received message
1513  *
1514  * This routine ensures a TIPC message has an acceptable header, and at least
1515  * as much data as the header indicates it should.  The routine also ensures
1516  * that the entire message header is stored in the main fragment of the message
1517  * buffer, to simplify future access to message header fields.
1518  *
1519  * Note: Having extra info present in the message header or data areas is OK.
1520  * TIPC will ignore the excess, under the assumption that it is optional info
1521  * introduced by a later release of the protocol.
1522  */
1523 static int link_recv_buf_validate(struct sk_buff *buf)
1524 {
1525         static u32 min_data_hdr_size[8] = {
1526                 SHORT_H_SIZE, MCAST_H_SIZE, NAMED_H_SIZE, BASIC_H_SIZE,
1527                 MAX_H_SIZE, MAX_H_SIZE, MAX_H_SIZE, MAX_H_SIZE
1528                 };
1529
1530         struct tipc_msg *msg;
1531         u32 tipc_hdr[2];
1532         u32 size;
1533         u32 hdr_size;
1534         u32 min_hdr_size;
1535
1536         if (unlikely(buf->len < MIN_H_SIZE))
1537                 return 0;
1538
1539         msg = skb_header_pointer(buf, 0, sizeof(tipc_hdr), tipc_hdr);
1540         if (msg == NULL)
1541                 return 0;
1542
1543         if (unlikely(msg_version(msg) != TIPC_VERSION))
1544                 return 0;
1545
1546         size = msg_size(msg);
1547         hdr_size = msg_hdr_sz(msg);
1548         min_hdr_size = msg_isdata(msg) ?
1549                 min_data_hdr_size[msg_type(msg)] : INT_H_SIZE;
1550
1551         if (unlikely((hdr_size < min_hdr_size) ||
1552                      (size < hdr_size) ||
1553                      (buf->len < size) ||
1554                      (size - hdr_size > TIPC_MAX_USER_MSG_SIZE)))
1555                 return 0;
1556
1557         return pskb_may_pull(buf, hdr_size);
1558 }
1559
1560 /**
1561  * tipc_recv_msg - process TIPC messages arriving from off-node
1562  * @head: pointer to message buffer chain
1563  * @tb_ptr: pointer to bearer message arrived on
1564  *
1565  * Invoked with no locks held.  Bearer pointer must point to a valid bearer
1566  * structure (i.e. cannot be NULL), but bearer can be inactive.
1567  */
1568 void tipc_recv_msg(struct sk_buff *head, struct tipc_bearer *b_ptr)
1569 {
1570         read_lock_bh(&tipc_net_lock);
1571         while (head) {
1572                 struct tipc_node *n_ptr;
1573                 struct tipc_link *l_ptr;
1574                 struct sk_buff *crs;
1575                 struct sk_buff *buf = head;
1576                 struct tipc_msg *msg;
1577                 u32 seq_no;
1578                 u32 ackd;
1579                 u32 released = 0;
1580                 int type;
1581
1582                 head = head->next;
1583
1584                 /* Ensure bearer is still enabled */
1585                 if (unlikely(!b_ptr->active))
1586                         goto cont;
1587
1588                 /* Ensure message is well-formed */
1589                 if (unlikely(!link_recv_buf_validate(buf)))
1590                         goto cont;
1591
1592                 /* Ensure message data is a single contiguous unit */
1593                 if (unlikely(skb_linearize(buf)))
1594                         goto cont;
1595
1596                 /* Handle arrival of a non-unicast link message */
1597                 msg = buf_msg(buf);
1598
1599                 if (unlikely(msg_non_seq(msg))) {
1600                         if (msg_user(msg) ==  LINK_CONFIG)
1601                                 tipc_disc_recv_msg(buf, b_ptr);
1602                         else
1603                                 tipc_bclink_recv_pkt(buf);
1604                         continue;
1605                 }
1606
1607                 /* Discard unicast link messages destined for another node */
1608                 if (unlikely(!msg_short(msg) &&
1609                              (msg_destnode(msg) != tipc_own_addr)))
1610                         goto cont;
1611
1612                 /* Locate neighboring node that sent message */
1613                 n_ptr = tipc_node_find(msg_prevnode(msg));
1614                 if (unlikely(!n_ptr))
1615                         goto cont;
1616                 tipc_node_lock(n_ptr);
1617
1618                 /* Locate unicast link endpoint that should handle message */
1619                 l_ptr = n_ptr->links[b_ptr->identity];
1620                 if (unlikely(!l_ptr)) {
1621                         tipc_node_unlock(n_ptr);
1622                         goto cont;
1623                 }
1624
1625                 /* Verify that communication with node is currently allowed */
1626                 if ((n_ptr->block_setup & WAIT_PEER_DOWN) &&
1627                         msg_user(msg) == LINK_PROTOCOL &&
1628                         (msg_type(msg) == RESET_MSG ||
1629                                         msg_type(msg) == ACTIVATE_MSG) &&
1630                         !msg_redundant_link(msg))
1631                         n_ptr->block_setup &= ~WAIT_PEER_DOWN;
1632
1633                 if (n_ptr->block_setup) {
1634                         tipc_node_unlock(n_ptr);
1635                         goto cont;
1636                 }
1637
1638                 /* Validate message sequence number info */
1639                 seq_no = msg_seqno(msg);
1640                 ackd = msg_ack(msg);
1641
1642                 /* Release acked messages */
1643                 if (n_ptr->bclink.recv_permitted)
1644                         tipc_bclink_acknowledge(n_ptr, msg_bcast_ack(msg));
1645
1646                 crs = l_ptr->first_out;
1647                 while ((crs != l_ptr->next_out) &&
1648                        less_eq(buf_seqno(crs), ackd)) {
1649                         struct sk_buff *next = crs->next;
1650
1651                         kfree_skb(crs);
1652                         crs = next;
1653                         released++;
1654                 }
1655                 if (released) {
1656                         l_ptr->first_out = crs;
1657                         l_ptr->out_queue_size -= released;
1658                 }
1659
1660                 /* Try sending any messages link endpoint has pending */
1661                 if (unlikely(l_ptr->next_out))
1662                         tipc_link_push_queue(l_ptr);
1663                 if (unlikely(!list_empty(&l_ptr->waiting_ports)))
1664                         tipc_link_wakeup_ports(l_ptr, 0);
1665                 if (unlikely(++l_ptr->unacked_window >= TIPC_MIN_LINK_WIN)) {
1666                         l_ptr->stats.sent_acks++;
1667                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
1668                 }
1669
1670                 /* Now (finally!) process the incoming message */
1671 protocol_check:
1672                 if (likely(link_working_working(l_ptr))) {
1673                         if (likely(seq_no == mod(l_ptr->next_in_no))) {
1674                                 l_ptr->next_in_no++;
1675                                 if (unlikely(l_ptr->oldest_deferred_in))
1676                                         head = link_insert_deferred_queue(l_ptr,
1677                                                                           head);
1678 deliver:
1679                                 if (likely(msg_isdata(msg))) {
1680                                         tipc_node_unlock(n_ptr);
1681                                         tipc_port_recv_msg(buf);
1682                                         continue;
1683                                 }
1684                                 switch (msg_user(msg)) {
1685                                         int ret;
1686                                 case MSG_BUNDLER:
1687                                         l_ptr->stats.recv_bundles++;
1688                                         l_ptr->stats.recv_bundled +=
1689                                                 msg_msgcnt(msg);
1690                                         tipc_node_unlock(n_ptr);
1691                                         tipc_link_recv_bundle(buf);
1692                                         continue;
1693                                 case NAME_DISTRIBUTOR:
1694                                         tipc_node_unlock(n_ptr);
1695                                         tipc_named_recv(buf);
1696                                         continue;
1697                                 case CONN_MANAGER:
1698                                         tipc_node_unlock(n_ptr);
1699                                         tipc_port_recv_proto_msg(buf);
1700                                         continue;
1701                                 case MSG_FRAGMENTER:
1702                                         l_ptr->stats.recv_fragments++;
1703                                         ret = tipc_link_recv_fragment(
1704                                                 &l_ptr->defragm_buf,
1705                                                 &buf, &msg);
1706                                         if (ret == 1) {
1707                                                 l_ptr->stats.recv_fragmented++;
1708                                                 goto deliver;
1709                                         }
1710                                         if (ret == -1)
1711                                                 l_ptr->next_in_no--;
1712                                         break;
1713                                 case CHANGEOVER_PROTOCOL:
1714                                         type = msg_type(msg);
1715                                         if (link_recv_changeover_msg(&l_ptr,
1716                                                                      &buf)) {
1717                                                 msg = buf_msg(buf);
1718                                                 seq_no = msg_seqno(msg);
1719                                                 if (type == ORIGINAL_MSG)
1720                                                         goto deliver;
1721                                                 goto protocol_check;
1722                                         }
1723                                         break;
1724                                 default:
1725                                         kfree_skb(buf);
1726                                         buf = NULL;
1727                                         break;
1728                                 }
1729                                 tipc_node_unlock(n_ptr);
1730                                 tipc_net_route_msg(buf);
1731                                 continue;
1732                         }
1733                         link_handle_out_of_seq_msg(l_ptr, buf);
1734                         head = link_insert_deferred_queue(l_ptr, head);
1735                         tipc_node_unlock(n_ptr);
1736                         continue;
1737                 }
1738
1739                 if (msg_user(msg) == LINK_PROTOCOL) {
1740                         link_recv_proto_msg(l_ptr, buf);
1741                         head = link_insert_deferred_queue(l_ptr, head);
1742                         tipc_node_unlock(n_ptr);
1743                         continue;
1744                 }
1745                 link_state_event(l_ptr, TRAFFIC_MSG_EVT);
1746
1747                 if (link_working_working(l_ptr)) {
1748                         /* Re-insert in front of queue */
1749                         buf->next = head;
1750                         head = buf;
1751                         tipc_node_unlock(n_ptr);
1752                         continue;
1753                 }
1754                 tipc_node_unlock(n_ptr);
1755 cont:
1756                 kfree_skb(buf);
1757         }
1758         read_unlock_bh(&tipc_net_lock);
1759 }
1760
1761 /**
1762  * tipc_link_defer_pkt - Add out-of-sequence message to deferred reception queue
1763  *
1764  * Returns increase in queue length (i.e. 0 or 1)
1765  */
1766 u32 tipc_link_defer_pkt(struct sk_buff **head, struct sk_buff **tail,
1767                         struct sk_buff *buf)
1768 {
1769         struct sk_buff *queue_buf;
1770         struct sk_buff **prev;
1771         u32 seq_no = buf_seqno(buf);
1772
1773         buf->next = NULL;
1774
1775         /* Empty queue ? */
1776         if (*head == NULL) {
1777                 *head = *tail = buf;
1778                 return 1;
1779         }
1780
1781         /* Last ? */
1782         if (less(buf_seqno(*tail), seq_no)) {
1783                 (*tail)->next = buf;
1784                 *tail = buf;
1785                 return 1;
1786         }
1787
1788         /* Locate insertion point in queue, then insert; discard if duplicate */
1789         prev = head;
1790         queue_buf = *head;
1791         for (;;) {
1792                 u32 curr_seqno = buf_seqno(queue_buf);
1793
1794                 if (seq_no == curr_seqno) {
1795                         kfree_skb(buf);
1796                         return 0;
1797                 }
1798
1799                 if (less(seq_no, curr_seqno))
1800                         break;
1801
1802                 prev = &queue_buf->next;
1803                 queue_buf = queue_buf->next;
1804         }
1805
1806         buf->next = queue_buf;
1807         *prev = buf;
1808         return 1;
1809 }
1810
1811 /*
1812  * link_handle_out_of_seq_msg - handle arrival of out-of-sequence packet
1813  */
1814 static void link_handle_out_of_seq_msg(struct tipc_link *l_ptr,
1815                                        struct sk_buff *buf)
1816 {
1817         u32 seq_no = buf_seqno(buf);
1818
1819         if (likely(msg_user(buf_msg(buf)) == LINK_PROTOCOL)) {
1820                 link_recv_proto_msg(l_ptr, buf);
1821                 return;
1822         }
1823
1824         /* Record OOS packet arrival (force mismatch on next timeout) */
1825         l_ptr->checkpoint--;
1826
1827         /*
1828          * Discard packet if a duplicate; otherwise add it to deferred queue
1829          * and notify peer of gap as per protocol specification
1830          */
1831         if (less(seq_no, mod(l_ptr->next_in_no))) {
1832                 l_ptr->stats.duplicates++;
1833                 kfree_skb(buf);
1834                 return;
1835         }
1836
1837         if (tipc_link_defer_pkt(&l_ptr->oldest_deferred_in,
1838                                 &l_ptr->newest_deferred_in, buf)) {
1839                 l_ptr->deferred_inqueue_sz++;
1840                 l_ptr->stats.deferred_recv++;
1841                 if ((l_ptr->deferred_inqueue_sz % 16) == 1)
1842                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
1843         } else
1844                 l_ptr->stats.duplicates++;
1845 }
1846
1847 /*
1848  * Send protocol message to the other endpoint.
1849  */
1850 void tipc_link_send_proto_msg(struct tipc_link *l_ptr, u32 msg_typ,
1851                                 int probe_msg, u32 gap, u32 tolerance,
1852                                 u32 priority, u32 ack_mtu)
1853 {
1854         struct sk_buff *buf = NULL;
1855         struct tipc_msg *msg = l_ptr->pmsg;
1856         u32 msg_size = sizeof(l_ptr->proto_msg);
1857         int r_flag;
1858
1859         /* Discard any previous message that was deferred due to congestion */
1860         if (l_ptr->proto_msg_queue) {
1861                 kfree_skb(l_ptr->proto_msg_queue);
1862                 l_ptr->proto_msg_queue = NULL;
1863         }
1864
1865         if (link_blocked(l_ptr))
1866                 return;
1867
1868         /* Abort non-RESET send if communication with node is prohibited */
1869         if ((l_ptr->owner->block_setup) && (msg_typ != RESET_MSG))
1870                 return;
1871
1872         /* Create protocol message with "out-of-sequence" sequence number */
1873         msg_set_type(msg, msg_typ);
1874         msg_set_net_plane(msg, l_ptr->b_ptr->net_plane);
1875         msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1876         msg_set_last_bcast(msg, tipc_bclink_get_last_sent());
1877
1878         if (msg_typ == STATE_MSG) {
1879                 u32 next_sent = mod(l_ptr->next_out_no);
1880
1881                 if (!tipc_link_is_up(l_ptr))
1882                         return;
1883                 if (l_ptr->next_out)
1884                         next_sent = buf_seqno(l_ptr->next_out);
1885                 msg_set_next_sent(msg, next_sent);
1886                 if (l_ptr->oldest_deferred_in) {
1887                         u32 rec = buf_seqno(l_ptr->oldest_deferred_in);
1888                         gap = mod(rec - mod(l_ptr->next_in_no));
1889                 }
1890                 msg_set_seq_gap(msg, gap);
1891                 if (gap)
1892                         l_ptr->stats.sent_nacks++;
1893                 msg_set_link_tolerance(msg, tolerance);
1894                 msg_set_linkprio(msg, priority);
1895                 msg_set_max_pkt(msg, ack_mtu);
1896                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1897                 msg_set_probe(msg, probe_msg != 0);
1898                 if (probe_msg) {
1899                         u32 mtu = l_ptr->max_pkt;
1900
1901                         if ((mtu < l_ptr->max_pkt_target) &&
1902                             link_working_working(l_ptr) &&
1903                             l_ptr->fsm_msg_cnt) {
1904                                 msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
1905                                 if (l_ptr->max_pkt_probes == 10) {
1906                                         l_ptr->max_pkt_target = (msg_size - 4);
1907                                         l_ptr->max_pkt_probes = 0;
1908                                         msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
1909                                 }
1910                                 l_ptr->max_pkt_probes++;
1911                         }
1912
1913                         l_ptr->stats.sent_probes++;
1914                 }
1915                 l_ptr->stats.sent_states++;
1916         } else {                /* RESET_MSG or ACTIVATE_MSG */
1917                 msg_set_ack(msg, mod(l_ptr->reset_checkpoint - 1));
1918                 msg_set_seq_gap(msg, 0);
1919                 msg_set_next_sent(msg, 1);
1920                 msg_set_probe(msg, 0);
1921                 msg_set_link_tolerance(msg, l_ptr->tolerance);
1922                 msg_set_linkprio(msg, l_ptr->priority);
1923                 msg_set_max_pkt(msg, l_ptr->max_pkt_target);
1924         }
1925
1926         r_flag = (l_ptr->owner->working_links > tipc_link_is_up(l_ptr));
1927         msg_set_redundant_link(msg, r_flag);
1928         msg_set_linkprio(msg, l_ptr->priority);
1929         msg_set_size(msg, msg_size);
1930
1931         msg_set_seqno(msg, mod(l_ptr->next_out_no + (0xffff/2)));
1932
1933         buf = tipc_buf_acquire(msg_size);
1934         if (!buf)
1935                 return;
1936
1937         skb_copy_to_linear_data(buf, msg, sizeof(l_ptr->proto_msg));
1938
1939         /* Defer message if bearer is already blocked */
1940         if (tipc_bearer_blocked(l_ptr->b_ptr)) {
1941                 l_ptr->proto_msg_queue = buf;
1942                 return;
1943         }
1944
1945         tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr);
1946         l_ptr->unacked_window = 0;
1947         kfree_skb(buf);
1948 }
1949
1950 /*
1951  * Receive protocol message :
1952  * Note that network plane id propagates through the network, and may
1953  * change at any time. The node with lowest address rules
1954  */
1955 static void link_recv_proto_msg(struct tipc_link *l_ptr, struct sk_buff *buf)
1956 {
1957         u32 rec_gap = 0;
1958         u32 max_pkt_info;
1959         u32 max_pkt_ack;
1960         u32 msg_tol;
1961         struct tipc_msg *msg = buf_msg(buf);
1962
1963         if (link_blocked(l_ptr))
1964                 goto exit;
1965
1966         /* record unnumbered packet arrival (force mismatch on next timeout) */
1967         l_ptr->checkpoint--;
1968
1969         if (l_ptr->b_ptr->net_plane != msg_net_plane(msg))
1970                 if (tipc_own_addr > msg_prevnode(msg))
1971                         l_ptr->b_ptr->net_plane = msg_net_plane(msg);
1972
1973         l_ptr->owner->permit_changeover = msg_redundant_link(msg);
1974
1975         switch (msg_type(msg)) {
1976
1977         case RESET_MSG:
1978                 if (!link_working_unknown(l_ptr) &&
1979                     (l_ptr->peer_session != INVALID_SESSION)) {
1980                         if (less_eq(msg_session(msg), l_ptr->peer_session))
1981                                 break; /* duplicate or old reset: ignore */
1982                 }
1983
1984                 if (!msg_redundant_link(msg) && (link_working_working(l_ptr) ||
1985                                 link_working_unknown(l_ptr))) {
1986                         /*
1987                          * peer has lost contact -- don't allow peer's links
1988                          * to reactivate before we recognize loss & clean up
1989                          */
1990                         l_ptr->owner->block_setup = WAIT_NODE_DOWN;
1991                 }
1992
1993                 link_state_event(l_ptr, RESET_MSG);
1994
1995                 /* fall thru' */
1996         case ACTIVATE_MSG:
1997                 /* Update link settings according other endpoint's values */
1998                 strcpy((strrchr(l_ptr->name, ':') + 1), (char *)msg_data(msg));
1999
2000                 msg_tol = msg_link_tolerance(msg);
2001                 if (msg_tol > l_ptr->tolerance)
2002                         link_set_supervision_props(l_ptr, msg_tol);
2003
2004                 if (msg_linkprio(msg) > l_ptr->priority)
2005                         l_ptr->priority = msg_linkprio(msg);
2006
2007                 max_pkt_info = msg_max_pkt(msg);
2008                 if (max_pkt_info) {
2009                         if (max_pkt_info < l_ptr->max_pkt_target)
2010                                 l_ptr->max_pkt_target = max_pkt_info;
2011                         if (l_ptr->max_pkt > l_ptr->max_pkt_target)
2012                                 l_ptr->max_pkt = l_ptr->max_pkt_target;
2013                 } else {
2014                         l_ptr->max_pkt = l_ptr->max_pkt_target;
2015                 }
2016
2017                 /* Synchronize broadcast link info, if not done previously */
2018                 if (!tipc_node_is_up(l_ptr->owner)) {
2019                         l_ptr->owner->bclink.last_sent =
2020                                 l_ptr->owner->bclink.last_in =
2021                                 msg_last_bcast(msg);
2022                         l_ptr->owner->bclink.oos_state = 0;
2023                 }
2024
2025                 l_ptr->peer_session = msg_session(msg);
2026                 l_ptr->peer_bearer_id = msg_bearer_id(msg);
2027
2028                 if (msg_type(msg) == ACTIVATE_MSG)
2029                         link_state_event(l_ptr, ACTIVATE_MSG);
2030                 break;
2031         case STATE_MSG:
2032
2033                 msg_tol = msg_link_tolerance(msg);
2034                 if (msg_tol)
2035                         link_set_supervision_props(l_ptr, msg_tol);
2036
2037                 if (msg_linkprio(msg) &&
2038                     (msg_linkprio(msg) != l_ptr->priority)) {
2039                         pr_warn("%s<%s>, priority change %u->%u\n",
2040                                 link_rst_msg, l_ptr->name, l_ptr->priority,
2041                                 msg_linkprio(msg));
2042                         l_ptr->priority = msg_linkprio(msg);
2043                         tipc_link_reset(l_ptr); /* Enforce change to take effect */
2044                         break;
2045                 }
2046                 link_state_event(l_ptr, TRAFFIC_MSG_EVT);
2047                 l_ptr->stats.recv_states++;
2048                 if (link_reset_unknown(l_ptr))
2049                         break;
2050
2051                 if (less_eq(mod(l_ptr->next_in_no), msg_next_sent(msg))) {
2052                         rec_gap = mod(msg_next_sent(msg) -
2053                                       mod(l_ptr->next_in_no));
2054                 }
2055
2056                 max_pkt_ack = msg_max_pkt(msg);
2057                 if (max_pkt_ack > l_ptr->max_pkt) {
2058                         l_ptr->max_pkt = max_pkt_ack;
2059                         l_ptr->max_pkt_probes = 0;
2060                 }
2061
2062                 max_pkt_ack = 0;
2063                 if (msg_probe(msg)) {
2064                         l_ptr->stats.recv_probes++;
2065                         if (msg_size(msg) > sizeof(l_ptr->proto_msg))
2066                                 max_pkt_ack = msg_size(msg);
2067                 }
2068
2069                 /* Protocol message before retransmits, reduce loss risk */
2070                 if (l_ptr->owner->bclink.recv_permitted)
2071                         tipc_bclink_update_link_state(l_ptr->owner,
2072                                                       msg_last_bcast(msg));
2073
2074                 if (rec_gap || (msg_probe(msg))) {
2075                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
2076                                                  0, rec_gap, 0, 0, max_pkt_ack);
2077                 }
2078                 if (msg_seq_gap(msg)) {
2079                         l_ptr->stats.recv_nacks++;
2080                         tipc_link_retransmit(l_ptr, l_ptr->first_out,
2081                                              msg_seq_gap(msg));
2082                 }
2083                 break;
2084         }
2085 exit:
2086         kfree_skb(buf);
2087 }
2088
2089
2090 /*
2091  * tipc_link_tunnel(): Send one message via a link belonging to
2092  * another bearer. Owner node is locked.
2093  */
2094 static void tipc_link_tunnel(struct tipc_link *l_ptr,
2095                              struct tipc_msg *tunnel_hdr,
2096                              struct tipc_msg  *msg,
2097                              u32 selector)
2098 {
2099         struct tipc_link *tunnel;
2100         struct sk_buff *buf;
2101         u32 length = msg_size(msg);
2102
2103         tunnel = l_ptr->owner->active_links[selector & 1];
2104         if (!tipc_link_is_up(tunnel)) {
2105                 pr_warn("%stunnel link no longer available\n", link_co_err);
2106                 return;
2107         }
2108         msg_set_size(tunnel_hdr, length + INT_H_SIZE);
2109         buf = tipc_buf_acquire(length + INT_H_SIZE);
2110         if (!buf) {
2111                 pr_warn("%sunable to send tunnel msg\n", link_co_err);
2112                 return;
2113         }
2114         skb_copy_to_linear_data(buf, tunnel_hdr, INT_H_SIZE);
2115         skb_copy_to_linear_data_offset(buf, INT_H_SIZE, msg, length);
2116         tipc_link_send_buf(tunnel, buf);
2117 }
2118
2119
2120
2121 /*
2122  * changeover(): Send whole message queue via the remaining link
2123  *               Owner node is locked.
2124  */
2125 void tipc_link_changeover(struct tipc_link *l_ptr)
2126 {
2127         u32 msgcount = l_ptr->out_queue_size;
2128         struct sk_buff *crs = l_ptr->first_out;
2129         struct tipc_link *tunnel = l_ptr->owner->active_links[0];
2130         struct tipc_msg tunnel_hdr;
2131         int split_bundles;
2132
2133         if (!tunnel)
2134                 return;
2135
2136         if (!l_ptr->owner->permit_changeover) {
2137                 pr_warn("%speer did not permit changeover\n", link_co_err);
2138                 return;
2139         }
2140
2141         tipc_msg_init(&tunnel_hdr, CHANGEOVER_PROTOCOL,
2142                  ORIGINAL_MSG, INT_H_SIZE, l_ptr->addr);
2143         msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
2144         msg_set_msgcnt(&tunnel_hdr, msgcount);
2145
2146         if (!l_ptr->first_out) {
2147                 struct sk_buff *buf;
2148
2149                 buf = tipc_buf_acquire(INT_H_SIZE);
2150                 if (buf) {
2151                         skb_copy_to_linear_data(buf, &tunnel_hdr, INT_H_SIZE);
2152                         msg_set_size(&tunnel_hdr, INT_H_SIZE);
2153                         tipc_link_send_buf(tunnel, buf);
2154                 } else {
2155                         pr_warn("%sunable to send changeover msg\n",
2156                                 link_co_err);
2157                 }
2158                 return;
2159         }
2160
2161         split_bundles = (l_ptr->owner->active_links[0] !=
2162                          l_ptr->owner->active_links[1]);
2163
2164         while (crs) {
2165                 struct tipc_msg *msg = buf_msg(crs);
2166
2167                 if ((msg_user(msg) == MSG_BUNDLER) && split_bundles) {
2168                         struct tipc_msg *m = msg_get_wrapped(msg);
2169                         unchar *pos = (unchar *)m;
2170
2171                         msgcount = msg_msgcnt(msg);
2172                         while (msgcount--) {
2173                                 msg_set_seqno(m, msg_seqno(msg));
2174                                 tipc_link_tunnel(l_ptr, &tunnel_hdr, m,
2175                                                  msg_link_selector(m));
2176                                 pos += align(msg_size(m));
2177                                 m = (struct tipc_msg *)pos;
2178                         }
2179                 } else {
2180                         tipc_link_tunnel(l_ptr, &tunnel_hdr, msg,
2181                                          msg_link_selector(msg));
2182                 }
2183                 crs = crs->next;
2184         }
2185 }
2186
2187 void tipc_link_send_duplicate(struct tipc_link *l_ptr, struct tipc_link *tunnel)
2188 {
2189         struct sk_buff *iter;
2190         struct tipc_msg tunnel_hdr;
2191
2192         tipc_msg_init(&tunnel_hdr, CHANGEOVER_PROTOCOL,
2193                  DUPLICATE_MSG, INT_H_SIZE, l_ptr->addr);
2194         msg_set_msgcnt(&tunnel_hdr, l_ptr->out_queue_size);
2195         msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
2196         iter = l_ptr->first_out;
2197         while (iter) {
2198                 struct sk_buff *outbuf;
2199                 struct tipc_msg *msg = buf_msg(iter);
2200                 u32 length = msg_size(msg);
2201
2202                 if (msg_user(msg) == MSG_BUNDLER)
2203                         msg_set_type(msg, CLOSED_MSG);
2204                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));   /* Update */
2205                 msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
2206                 msg_set_size(&tunnel_hdr, length + INT_H_SIZE);
2207                 outbuf = tipc_buf_acquire(length + INT_H_SIZE);
2208                 if (outbuf == NULL) {
2209                         pr_warn("%sunable to send duplicate msg\n",
2210                                 link_co_err);
2211                         return;
2212                 }
2213                 skb_copy_to_linear_data(outbuf, &tunnel_hdr, INT_H_SIZE);
2214                 skb_copy_to_linear_data_offset(outbuf, INT_H_SIZE, iter->data,
2215                                                length);
2216                 tipc_link_send_buf(tunnel, outbuf);
2217                 if (!tipc_link_is_up(l_ptr))
2218                         return;
2219                 iter = iter->next;
2220         }
2221 }
2222
2223 /**
2224  * buf_extract - extracts embedded TIPC message from another message
2225  * @skb: encapsulating message buffer
2226  * @from_pos: offset to extract from
2227  *
2228  * Returns a new message buffer containing an embedded message.  The
2229  * encapsulating message itself is left unchanged.
2230  */
2231 static struct sk_buff *buf_extract(struct sk_buff *skb, u32 from_pos)
2232 {
2233         struct tipc_msg *msg = (struct tipc_msg *)(skb->data + from_pos);
2234         u32 size = msg_size(msg);
2235         struct sk_buff *eb;
2236
2237         eb = tipc_buf_acquire(size);
2238         if (eb)
2239                 skb_copy_to_linear_data(eb, msg, size);
2240         return eb;
2241 }
2242
2243 /*
2244  *  link_recv_changeover_msg(): Receive tunneled packet sent
2245  *  via other link. Node is locked. Return extracted buffer.
2246  */
2247 static int link_recv_changeover_msg(struct tipc_link **l_ptr,
2248                                     struct sk_buff **buf)
2249 {
2250         struct sk_buff *tunnel_buf = *buf;
2251         struct tipc_link *dest_link;
2252         struct tipc_msg *msg;
2253         struct tipc_msg *tunnel_msg = buf_msg(tunnel_buf);
2254         u32 msg_typ = msg_type(tunnel_msg);
2255         u32 msg_count = msg_msgcnt(tunnel_msg);
2256
2257         dest_link = (*l_ptr)->owner->links[msg_bearer_id(tunnel_msg)];
2258         if (!dest_link)
2259                 goto exit;
2260         if (dest_link == *l_ptr) {
2261                 pr_err("Unexpected changeover message on link <%s>\n",
2262                        (*l_ptr)->name);
2263                 goto exit;
2264         }
2265         *l_ptr = dest_link;
2266         msg = msg_get_wrapped(tunnel_msg);
2267
2268         if (msg_typ == DUPLICATE_MSG) {
2269                 if (less(msg_seqno(msg), mod(dest_link->next_in_no)))
2270                         goto exit;
2271                 *buf = buf_extract(tunnel_buf, INT_H_SIZE);
2272                 if (*buf == NULL) {
2273                         pr_warn("%sduplicate msg dropped\n", link_co_err);
2274                         goto exit;
2275                 }
2276                 kfree_skb(tunnel_buf);
2277                 return 1;
2278         }
2279
2280         /* First original message ?: */
2281         if (tipc_link_is_up(dest_link)) {
2282                 pr_info("%s<%s>, changeover initiated by peer\n", link_rst_msg,
2283                         dest_link->name);
2284                 tipc_link_reset(dest_link);
2285                 dest_link->exp_msg_count = msg_count;
2286                 if (!msg_count)
2287                         goto exit;
2288         } else if (dest_link->exp_msg_count == START_CHANGEOVER) {
2289                 dest_link->exp_msg_count = msg_count;
2290                 if (!msg_count)
2291                         goto exit;
2292         }
2293
2294         /* Receive original message */
2295         if (dest_link->exp_msg_count == 0) {
2296                 pr_warn("%sgot too many tunnelled messages\n", link_co_err);
2297                 goto exit;
2298         }
2299         dest_link->exp_msg_count--;
2300         if (less(msg_seqno(msg), dest_link->reset_checkpoint)) {
2301                 goto exit;
2302         } else {
2303                 *buf = buf_extract(tunnel_buf, INT_H_SIZE);
2304                 if (*buf != NULL) {
2305                         kfree_skb(tunnel_buf);
2306                         return 1;
2307                 } else {
2308                         pr_warn("%soriginal msg dropped\n", link_co_err);
2309                 }
2310         }
2311 exit:
2312         *buf = NULL;
2313         kfree_skb(tunnel_buf);
2314         return 0;
2315 }
2316
2317 /*
2318  *  Bundler functionality:
2319  */
2320 void tipc_link_recv_bundle(struct sk_buff *buf)
2321 {
2322         u32 msgcount = msg_msgcnt(buf_msg(buf));
2323         u32 pos = INT_H_SIZE;
2324         struct sk_buff *obuf;
2325
2326         while (msgcount--) {
2327                 obuf = buf_extract(buf, pos);
2328                 if (obuf == NULL) {
2329                         pr_warn("Link unable to unbundle message(s)\n");
2330                         break;
2331                 }
2332                 pos += align(msg_size(buf_msg(obuf)));
2333                 tipc_net_route_msg(obuf);
2334         }
2335         kfree_skb(buf);
2336 }
2337
2338 /*
2339  *  Fragmentation/defragmentation:
2340  */
2341
2342 /*
2343  * link_send_long_buf: Entry for buffers needing fragmentation.
2344  * The buffer is complete, inclusive total message length.
2345  * Returns user data length.
2346  */
2347 static int link_send_long_buf(struct tipc_link *l_ptr, struct sk_buff *buf)
2348 {
2349         struct sk_buff *buf_chain = NULL;
2350         struct sk_buff *buf_chain_tail = (struct sk_buff *)&buf_chain;
2351         struct tipc_msg *inmsg = buf_msg(buf);
2352         struct tipc_msg fragm_hdr;
2353         u32 insize = msg_size(inmsg);
2354         u32 dsz = msg_data_sz(inmsg);
2355         unchar *crs = buf->data;
2356         u32 rest = insize;
2357         u32 pack_sz = l_ptr->max_pkt;
2358         u32 fragm_sz = pack_sz - INT_H_SIZE;
2359         u32 fragm_no = 0;
2360         u32 destaddr;
2361
2362         if (msg_short(inmsg))
2363                 destaddr = l_ptr->addr;
2364         else
2365                 destaddr = msg_destnode(inmsg);
2366
2367         /* Prepare reusable fragment header: */
2368         tipc_msg_init(&fragm_hdr, MSG_FRAGMENTER, FIRST_FRAGMENT,
2369                  INT_H_SIZE, destaddr);
2370
2371         /* Chop up message: */
2372         while (rest > 0) {
2373                 struct sk_buff *fragm;
2374
2375                 if (rest <= fragm_sz) {
2376                         fragm_sz = rest;
2377                         msg_set_type(&fragm_hdr, LAST_FRAGMENT);
2378                 }
2379                 fragm = tipc_buf_acquire(fragm_sz + INT_H_SIZE);
2380                 if (fragm == NULL) {
2381                         kfree_skb(buf);
2382                         while (buf_chain) {
2383                                 buf = buf_chain;
2384                                 buf_chain = buf_chain->next;
2385                                 kfree_skb(buf);
2386                         }
2387                         return -ENOMEM;
2388                 }
2389                 msg_set_size(&fragm_hdr, fragm_sz + INT_H_SIZE);
2390                 fragm_no++;
2391                 msg_set_fragm_no(&fragm_hdr, fragm_no);
2392                 skb_copy_to_linear_data(fragm, &fragm_hdr, INT_H_SIZE);
2393                 skb_copy_to_linear_data_offset(fragm, INT_H_SIZE, crs,
2394                                                fragm_sz);
2395                 buf_chain_tail->next = fragm;
2396                 buf_chain_tail = fragm;
2397
2398                 rest -= fragm_sz;
2399                 crs += fragm_sz;
2400                 msg_set_type(&fragm_hdr, FRAGMENT);
2401         }
2402         kfree_skb(buf);
2403
2404         /* Append chain of fragments to send queue & send them */
2405         l_ptr->long_msg_seq_no++;
2406         link_add_chain_to_outqueue(l_ptr, buf_chain, l_ptr->long_msg_seq_no);
2407         l_ptr->stats.sent_fragments += fragm_no;
2408         l_ptr->stats.sent_fragmented++;
2409         tipc_link_push_queue(l_ptr);
2410
2411         return dsz;
2412 }
2413
2414 /*
2415  * A pending message being re-assembled must store certain values
2416  * to handle subsequent fragments correctly. The following functions
2417  * help storing these values in unused, available fields in the
2418  * pending message. This makes dynamic memory allocation unnecessary.
2419  */
2420 static void set_long_msg_seqno(struct sk_buff *buf, u32 seqno)
2421 {
2422         msg_set_seqno(buf_msg(buf), seqno);
2423 }
2424
2425 static u32 get_fragm_size(struct sk_buff *buf)
2426 {
2427         return msg_ack(buf_msg(buf));
2428 }
2429
2430 static void set_fragm_size(struct sk_buff *buf, u32 sz)
2431 {
2432         msg_set_ack(buf_msg(buf), sz);
2433 }
2434
2435 static u32 get_expected_frags(struct sk_buff *buf)
2436 {
2437         return msg_bcast_ack(buf_msg(buf));
2438 }
2439
2440 static void set_expected_frags(struct sk_buff *buf, u32 exp)
2441 {
2442         msg_set_bcast_ack(buf_msg(buf), exp);
2443 }
2444
2445 static u32 get_timer_cnt(struct sk_buff *buf)
2446 {
2447         return msg_reroute_cnt(buf_msg(buf));
2448 }
2449
2450 static void incr_timer_cnt(struct sk_buff *buf)
2451 {
2452         msg_incr_reroute_cnt(buf_msg(buf));
2453 }
2454
2455 /*
2456  * tipc_link_recv_fragment(): Called with node lock on. Returns
2457  * the reassembled buffer if message is complete.
2458  */
2459 int tipc_link_recv_fragment(struct sk_buff **pending, struct sk_buff **fb,
2460                             struct tipc_msg **m)
2461 {
2462         struct sk_buff *prev = NULL;
2463         struct sk_buff *fbuf = *fb;
2464         struct tipc_msg *fragm = buf_msg(fbuf);
2465         struct sk_buff *pbuf = *pending;
2466         u32 long_msg_seq_no = msg_long_msgno(fragm);
2467
2468         *fb = NULL;
2469
2470         /* Is there an incomplete message waiting for this fragment? */
2471         while (pbuf && ((buf_seqno(pbuf) != long_msg_seq_no) ||
2472                         (msg_orignode(fragm) != msg_orignode(buf_msg(pbuf))))) {
2473                 prev = pbuf;
2474                 pbuf = pbuf->next;
2475         }
2476
2477         if (!pbuf && (msg_type(fragm) == FIRST_FRAGMENT)) {
2478                 struct tipc_msg *imsg = (struct tipc_msg *)msg_data(fragm);
2479                 u32 msg_sz = msg_size(imsg);
2480                 u32 fragm_sz = msg_data_sz(fragm);
2481                 u32 exp_fragm_cnt = msg_sz/fragm_sz + !!(msg_sz % fragm_sz);
2482                 u32 max =  TIPC_MAX_USER_MSG_SIZE + NAMED_H_SIZE;
2483                 if (msg_type(imsg) == TIPC_MCAST_MSG)
2484                         max = TIPC_MAX_USER_MSG_SIZE + MCAST_H_SIZE;
2485                 if (msg_size(imsg) > max) {
2486                         kfree_skb(fbuf);
2487                         return 0;
2488                 }
2489                 pbuf = tipc_buf_acquire(msg_size(imsg));
2490                 if (pbuf != NULL) {
2491                         pbuf->next = *pending;
2492                         *pending = pbuf;
2493                         skb_copy_to_linear_data(pbuf, imsg,
2494                                                 msg_data_sz(fragm));
2495                         /*  Prepare buffer for subsequent fragments. */
2496                         set_long_msg_seqno(pbuf, long_msg_seq_no);
2497                         set_fragm_size(pbuf, fragm_sz);
2498                         set_expected_frags(pbuf, exp_fragm_cnt - 1);
2499                 } else {
2500                         pr_debug("Link unable to reassemble fragmented message\n");
2501                         kfree_skb(fbuf);
2502                         return -1;
2503                 }
2504                 kfree_skb(fbuf);
2505                 return 0;
2506         } else if (pbuf && (msg_type(fragm) != FIRST_FRAGMENT)) {
2507                 u32 dsz = msg_data_sz(fragm);
2508                 u32 fsz = get_fragm_size(pbuf);
2509                 u32 crs = ((msg_fragm_no(fragm) - 1) * fsz);
2510                 u32 exp_frags = get_expected_frags(pbuf) - 1;
2511                 skb_copy_to_linear_data_offset(pbuf, crs,
2512                                                msg_data(fragm), dsz);
2513                 kfree_skb(fbuf);
2514
2515                 /* Is message complete? */
2516                 if (exp_frags == 0) {
2517                         if (prev)
2518                                 prev->next = pbuf->next;
2519                         else
2520                                 *pending = pbuf->next;
2521                         msg_reset_reroute_cnt(buf_msg(pbuf));
2522                         *fb = pbuf;
2523                         *m = buf_msg(pbuf);
2524                         return 1;
2525                 }
2526                 set_expected_frags(pbuf, exp_frags);
2527                 return 0;
2528         }
2529         kfree_skb(fbuf);
2530         return 0;
2531 }
2532
2533 /**
2534  * link_check_defragm_bufs - flush stale incoming message fragments
2535  * @l_ptr: pointer to link
2536  */
2537 static void link_check_defragm_bufs(struct tipc_link *l_ptr)
2538 {
2539         struct sk_buff *prev = NULL;
2540         struct sk_buff *next = NULL;
2541         struct sk_buff *buf = l_ptr->defragm_buf;
2542
2543         if (!buf)
2544                 return;
2545         if (!link_working_working(l_ptr))
2546                 return;
2547         while (buf) {
2548                 u32 cnt = get_timer_cnt(buf);
2549
2550                 next = buf->next;
2551                 if (cnt < 4) {
2552                         incr_timer_cnt(buf);
2553                         prev = buf;
2554                 } else {
2555                         if (prev)
2556                                 prev->next = buf->next;
2557                         else
2558                                 l_ptr->defragm_buf = buf->next;
2559                         kfree_skb(buf);
2560                 }
2561                 buf = next;
2562         }
2563 }
2564
2565 static void link_set_supervision_props(struct tipc_link *l_ptr, u32 tolerance)
2566 {
2567         if ((tolerance < TIPC_MIN_LINK_TOL) || (tolerance > TIPC_MAX_LINK_TOL))
2568                 return;
2569
2570         l_ptr->tolerance = tolerance;
2571         l_ptr->continuity_interval =
2572                 ((tolerance / 4) > 500) ? 500 : tolerance / 4;
2573         l_ptr->abort_limit = tolerance / (l_ptr->continuity_interval / 4);
2574 }
2575
2576 void tipc_link_set_queue_limits(struct tipc_link *l_ptr, u32 window)
2577 {
2578         /* Data messages from this node, inclusive FIRST_FRAGM */
2579         l_ptr->queue_limit[TIPC_LOW_IMPORTANCE] = window;
2580         l_ptr->queue_limit[TIPC_MEDIUM_IMPORTANCE] = (window / 3) * 4;
2581         l_ptr->queue_limit[TIPC_HIGH_IMPORTANCE] = (window / 3) * 5;
2582         l_ptr->queue_limit[TIPC_CRITICAL_IMPORTANCE] = (window / 3) * 6;
2583         /* Transiting data messages,inclusive FIRST_FRAGM */
2584         l_ptr->queue_limit[TIPC_LOW_IMPORTANCE + 4] = 300;
2585         l_ptr->queue_limit[TIPC_MEDIUM_IMPORTANCE + 4] = 600;
2586         l_ptr->queue_limit[TIPC_HIGH_IMPORTANCE + 4] = 900;
2587         l_ptr->queue_limit[TIPC_CRITICAL_IMPORTANCE + 4] = 1200;
2588         l_ptr->queue_limit[CONN_MANAGER] = 1200;
2589         l_ptr->queue_limit[CHANGEOVER_PROTOCOL] = 2500;
2590         l_ptr->queue_limit[NAME_DISTRIBUTOR] = 3000;
2591         /* FRAGMENT and LAST_FRAGMENT packets */
2592         l_ptr->queue_limit[MSG_FRAGMENTER] = 4000;
2593 }
2594
2595 /**
2596  * link_find_link - locate link by name
2597  * @name: ptr to link name string
2598  * @node: ptr to area to be filled with ptr to associated node
2599  *
2600  * Caller must hold 'tipc_net_lock' to ensure node and bearer are not deleted;
2601  * this also prevents link deletion.
2602  *
2603  * Returns pointer to link (or 0 if invalid link name).
2604  */
2605 static struct tipc_link *link_find_link(const char *name,
2606                                         struct tipc_node **node)
2607 {
2608         struct tipc_link_name link_name_parts;
2609         struct tipc_bearer *b_ptr;
2610         struct tipc_link *l_ptr;
2611
2612         if (!link_name_validate(name, &link_name_parts))
2613                 return NULL;
2614
2615         b_ptr = tipc_bearer_find_interface(link_name_parts.if_local);
2616         if (!b_ptr)
2617                 return NULL;
2618
2619         *node = tipc_node_find(link_name_parts.addr_peer);
2620         if (!*node)
2621                 return NULL;
2622
2623         l_ptr = (*node)->links[b_ptr->identity];
2624         if (!l_ptr || strcmp(l_ptr->name, name))
2625                 return NULL;
2626
2627         return l_ptr;
2628 }
2629
2630 /**
2631  * link_value_is_valid -- validate proposed link tolerance/priority/window
2632  *
2633  * @cmd: value type (TIPC_CMD_SET_LINK_*)
2634  * @new_value: the new value
2635  *
2636  * Returns 1 if value is within range, 0 if not.
2637  */
2638 static int link_value_is_valid(u16 cmd, u32 new_value)
2639 {
2640         switch (cmd) {
2641         case TIPC_CMD_SET_LINK_TOL:
2642                 return (new_value >= TIPC_MIN_LINK_TOL) &&
2643                         (new_value <= TIPC_MAX_LINK_TOL);
2644         case TIPC_CMD_SET_LINK_PRI:
2645                 return (new_value <= TIPC_MAX_LINK_PRI);
2646         case TIPC_CMD_SET_LINK_WINDOW:
2647                 return (new_value >= TIPC_MIN_LINK_WIN) &&
2648                         (new_value <= TIPC_MAX_LINK_WIN);
2649         }
2650         return 0;
2651 }
2652
2653 /**
2654  * link_cmd_set_value - change priority/tolerance/window for link/bearer/media
2655  * @name: ptr to link, bearer, or media name
2656  * @new_value: new value of link, bearer, or media setting
2657  * @cmd: which link, bearer, or media attribute to set (TIPC_CMD_SET_LINK_*)
2658  *
2659  * Caller must hold 'tipc_net_lock' to ensure link/bearer/media is not deleted.
2660  *
2661  * Returns 0 if value updated and negative value on error.
2662  */
2663 static int link_cmd_set_value(const char *name, u32 new_value, u16 cmd)
2664 {
2665         struct tipc_node *node;
2666         struct tipc_link *l_ptr;
2667         struct tipc_bearer *b_ptr;
2668         struct tipc_media *m_ptr;
2669
2670         l_ptr = link_find_link(name, &node);
2671         if (l_ptr) {
2672                 /*
2673                  * acquire node lock for tipc_link_send_proto_msg().
2674                  * see "TIPC locking policy" in net.c.
2675                  */
2676                 tipc_node_lock(node);
2677                 switch (cmd) {
2678                 case TIPC_CMD_SET_LINK_TOL:
2679                         link_set_supervision_props(l_ptr, new_value);
2680                         tipc_link_send_proto_msg(l_ptr,
2681                                 STATE_MSG, 0, 0, new_value, 0, 0);
2682                         break;
2683                 case TIPC_CMD_SET_LINK_PRI:
2684                         l_ptr->priority = new_value;
2685                         tipc_link_send_proto_msg(l_ptr,
2686                                 STATE_MSG, 0, 0, 0, new_value, 0);
2687                         break;
2688                 case TIPC_CMD_SET_LINK_WINDOW:
2689                         tipc_link_set_queue_limits(l_ptr, new_value);
2690                         break;
2691                 }
2692                 tipc_node_unlock(node);
2693                 return 0;
2694         }
2695
2696         b_ptr = tipc_bearer_find(name);
2697         if (b_ptr) {
2698                 switch (cmd) {
2699                 case TIPC_CMD_SET_LINK_TOL:
2700                         b_ptr->tolerance = new_value;
2701                         return 0;
2702                 case TIPC_CMD_SET_LINK_PRI:
2703                         b_ptr->priority = new_value;
2704                         return 0;
2705                 case TIPC_CMD_SET_LINK_WINDOW:
2706                         b_ptr->window = new_value;
2707                         return 0;
2708                 }
2709                 return -EINVAL;
2710         }
2711
2712         m_ptr = tipc_media_find(name);
2713         if (!m_ptr)
2714                 return -ENODEV;
2715         switch (cmd) {
2716         case TIPC_CMD_SET_LINK_TOL:
2717                 m_ptr->tolerance = new_value;
2718                 return 0;
2719         case TIPC_CMD_SET_LINK_PRI:
2720                 m_ptr->priority = new_value;
2721                 return 0;
2722         case TIPC_CMD_SET_LINK_WINDOW:
2723                 m_ptr->window = new_value;
2724                 return 0;
2725         }
2726         return -EINVAL;
2727 }
2728
2729 struct sk_buff *tipc_link_cmd_config(const void *req_tlv_area, int req_tlv_space,
2730                                      u16 cmd)
2731 {
2732         struct tipc_link_config *args;
2733         u32 new_value;
2734         int res;
2735
2736         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_CONFIG))
2737                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2738
2739         args = (struct tipc_link_config *)TLV_DATA(req_tlv_area);
2740         new_value = ntohl(args->value);
2741
2742         if (!link_value_is_valid(cmd, new_value))
2743                 return tipc_cfg_reply_error_string(
2744                         "cannot change, value invalid");
2745
2746         if (!strcmp(args->name, tipc_bclink_name)) {
2747                 if ((cmd == TIPC_CMD_SET_LINK_WINDOW) &&
2748                     (tipc_bclink_set_queue_limits(new_value) == 0))
2749                         return tipc_cfg_reply_none();
2750                 return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
2751                                                    " (cannot change setting on broadcast link)");
2752         }
2753
2754         read_lock_bh(&tipc_net_lock);
2755         res = link_cmd_set_value(args->name, new_value, cmd);
2756         read_unlock_bh(&tipc_net_lock);
2757         if (res)
2758                 return tipc_cfg_reply_error_string("cannot change link setting");
2759
2760         return tipc_cfg_reply_none();
2761 }
2762
2763 /**
2764  * link_reset_statistics - reset link statistics
2765  * @l_ptr: pointer to link
2766  */
2767 static void link_reset_statistics(struct tipc_link *l_ptr)
2768 {
2769         memset(&l_ptr->stats, 0, sizeof(l_ptr->stats));
2770         l_ptr->stats.sent_info = l_ptr->next_out_no;
2771         l_ptr->stats.recv_info = l_ptr->next_in_no;
2772 }
2773
2774 struct sk_buff *tipc_link_cmd_reset_stats(const void *req_tlv_area, int req_tlv_space)
2775 {
2776         char *link_name;
2777         struct tipc_link *l_ptr;
2778         struct tipc_node *node;
2779
2780         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_NAME))
2781                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2782
2783         link_name = (char *)TLV_DATA(req_tlv_area);
2784         if (!strcmp(link_name, tipc_bclink_name)) {
2785                 if (tipc_bclink_reset_stats())
2786                         return tipc_cfg_reply_error_string("link not found");
2787                 return tipc_cfg_reply_none();
2788         }
2789
2790         read_lock_bh(&tipc_net_lock);
2791         l_ptr = link_find_link(link_name, &node);
2792         if (!l_ptr) {
2793                 read_unlock_bh(&tipc_net_lock);
2794                 return tipc_cfg_reply_error_string("link not found");
2795         }
2796
2797         tipc_node_lock(node);
2798         link_reset_statistics(l_ptr);
2799         tipc_node_unlock(node);
2800         read_unlock_bh(&tipc_net_lock);
2801         return tipc_cfg_reply_none();
2802 }
2803
2804 /**
2805  * percent - convert count to a percentage of total (rounding up or down)
2806  */
2807 static u32 percent(u32 count, u32 total)
2808 {
2809         return (count * 100 + (total / 2)) / total;
2810 }
2811
2812 /**
2813  * tipc_link_stats - print link statistics
2814  * @name: link name
2815  * @buf: print buffer area
2816  * @buf_size: size of print buffer area
2817  *
2818  * Returns length of print buffer data string (or 0 if error)
2819  */
2820 static int tipc_link_stats(const char *name, char *buf, const u32 buf_size)
2821 {
2822         struct tipc_link *l;
2823         struct tipc_stats *s;
2824         struct tipc_node *node;
2825         char *status;
2826         u32 profile_total = 0;
2827         int ret;
2828
2829         if (!strcmp(name, tipc_bclink_name))
2830                 return tipc_bclink_stats(buf, buf_size);
2831
2832         read_lock_bh(&tipc_net_lock);
2833         l = link_find_link(name, &node);
2834         if (!l) {
2835                 read_unlock_bh(&tipc_net_lock);
2836                 return 0;
2837         }
2838         tipc_node_lock(node);
2839         s = &l->stats;
2840
2841         if (tipc_link_is_active(l))
2842                 status = "ACTIVE";
2843         else if (tipc_link_is_up(l))
2844                 status = "STANDBY";
2845         else
2846                 status = "DEFUNCT";
2847
2848         ret = tipc_snprintf(buf, buf_size, "Link <%s>\n"
2849                             "  %s  MTU:%u  Priority:%u  Tolerance:%u ms"
2850                             "  Window:%u packets\n",
2851                             l->name, status, l->max_pkt, l->priority,
2852                             l->tolerance, l->queue_limit[0]);
2853
2854         ret += tipc_snprintf(buf + ret, buf_size - ret,
2855                              "  RX packets:%u fragments:%u/%u bundles:%u/%u\n",
2856                              l->next_in_no - s->recv_info, s->recv_fragments,
2857                              s->recv_fragmented, s->recv_bundles,
2858                              s->recv_bundled);
2859
2860         ret += tipc_snprintf(buf + ret, buf_size - ret,
2861                              "  TX packets:%u fragments:%u/%u bundles:%u/%u\n",
2862                              l->next_out_no - s->sent_info, s->sent_fragments,
2863                              s->sent_fragmented, s->sent_bundles,
2864                              s->sent_bundled);
2865
2866         profile_total = s->msg_length_counts;
2867         if (!profile_total)
2868                 profile_total = 1;
2869
2870         ret += tipc_snprintf(buf + ret, buf_size - ret,
2871                              "  TX profile sample:%u packets  average:%u octets\n"
2872                              "  0-64:%u%% -256:%u%% -1024:%u%% -4096:%u%% "
2873                              "-16384:%u%% -32768:%u%% -66000:%u%%\n",
2874                              s->msg_length_counts,
2875                              s->msg_lengths_total / profile_total,
2876                              percent(s->msg_length_profile[0], profile_total),
2877                              percent(s->msg_length_profile[1], profile_total),
2878                              percent(s->msg_length_profile[2], profile_total),
2879                              percent(s->msg_length_profile[3], profile_total),
2880                              percent(s->msg_length_profile[4], profile_total),
2881                              percent(s->msg_length_profile[5], profile_total),
2882                              percent(s->msg_length_profile[6], profile_total));
2883
2884         ret += tipc_snprintf(buf + ret, buf_size - ret,
2885                              "  RX states:%u probes:%u naks:%u defs:%u"
2886                              " dups:%u\n", s->recv_states, s->recv_probes,
2887                              s->recv_nacks, s->deferred_recv, s->duplicates);
2888
2889         ret += tipc_snprintf(buf + ret, buf_size - ret,
2890                              "  TX states:%u probes:%u naks:%u acks:%u"
2891                              " dups:%u\n", s->sent_states, s->sent_probes,
2892                              s->sent_nacks, s->sent_acks, s->retransmitted);
2893
2894         ret += tipc_snprintf(buf + ret, buf_size - ret,
2895                              "  Congestion link:%u  Send queue"
2896                              " max:%u avg:%u\n", s->link_congs,
2897                              s->max_queue_sz, s->queue_sz_counts ?
2898                              (s->accu_queue_sz / s->queue_sz_counts) : 0);
2899
2900         tipc_node_unlock(node);
2901         read_unlock_bh(&tipc_net_lock);
2902         return ret;
2903 }
2904
2905 struct sk_buff *tipc_link_cmd_show_stats(const void *req_tlv_area, int req_tlv_space)
2906 {
2907         struct sk_buff *buf;
2908         struct tlv_desc *rep_tlv;
2909         int str_len;
2910         int pb_len;
2911         char *pb;
2912
2913         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_NAME))
2914                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2915
2916         buf = tipc_cfg_reply_alloc(TLV_SPACE(ULTRA_STRING_MAX_LEN));
2917         if (!buf)
2918                 return NULL;
2919
2920         rep_tlv = (struct tlv_desc *)buf->data;
2921         pb = TLV_DATA(rep_tlv);
2922         pb_len = ULTRA_STRING_MAX_LEN;
2923         str_len = tipc_link_stats((char *)TLV_DATA(req_tlv_area),
2924                                   pb, pb_len);
2925         if (!str_len) {
2926                 kfree_skb(buf);
2927                 return tipc_cfg_reply_error_string("link not found");
2928         }
2929         str_len += 1;   /* for "\0" */
2930         skb_put(buf, TLV_SPACE(str_len));
2931         TLV_SET(rep_tlv, TIPC_TLV_ULTRA_STRING, NULL, str_len);
2932
2933         return buf;
2934 }
2935
2936 /**
2937  * tipc_link_get_max_pkt - get maximum packet size to use when sending to destination
2938  * @dest: network address of destination node
2939  * @selector: used to select from set of active links
2940  *
2941  * If no active link can be found, uses default maximum packet size.
2942  */
2943 u32 tipc_link_get_max_pkt(u32 dest, u32 selector)
2944 {
2945         struct tipc_node *n_ptr;
2946         struct tipc_link *l_ptr;
2947         u32 res = MAX_PKT_DEFAULT;
2948
2949         if (dest == tipc_own_addr)
2950                 return MAX_MSG_SIZE;
2951
2952         read_lock_bh(&tipc_net_lock);
2953         n_ptr = tipc_node_find(dest);
2954         if (n_ptr) {
2955                 tipc_node_lock(n_ptr);
2956                 l_ptr = n_ptr->active_links[selector & 1];
2957                 if (l_ptr)
2958                         res = l_ptr->max_pkt;
2959                 tipc_node_unlock(n_ptr);
2960         }
2961         read_unlock_bh(&tipc_net_lock);
2962         return res;
2963 }
2964
2965 static void link_print(struct tipc_link *l_ptr, const char *str)
2966 {
2967         pr_info("%s Link %x<%s>:", str, l_ptr->addr, l_ptr->b_ptr->name);
2968
2969         if (link_working_unknown(l_ptr))
2970                 pr_cont(":WU\n");
2971         else if (link_reset_reset(l_ptr))
2972                 pr_cont(":RR\n");
2973         else if (link_reset_unknown(l_ptr))
2974                 pr_cont(":RU\n");
2975         else if (link_working_working(l_ptr))
2976                 pr_cont(":WW\n");
2977         else
2978                 pr_cont("\n");
2979 }