net/tipc/link.c

   1 /*
   2  * net/tipc/link.c: TIPC link code
   3  *
   4  * Copyright (c) 1996-2007, 2012-2014, Ericsson AB
   5  * Copyright (c) 2004-2007, 2010-2013, 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 "socket.h"
  40 #include "name_distr.h"
  41 #include "discover.h"
  42 #include "config.h"
  43
  44 #include <linux/pkt_sched.h>
  45
  46 /*
  47  * Error message prefixes
  48  */
  49 static const char *link_co_err = "Link changeover error, ";
  50 static const char *link_rst_msg = "Resetting link ";
  51 static const char *link_unk_evt = "Unknown link event ";
  52
  53 /*
  54  * Out-of-range value for link session numbers
  55  */
  56 #define INVALID_SESSION 0x10000
  57
  58 /*
  59  * Link state events:
  60  */
  61 #define  STARTING_EVT    856384768      /* link processing trigger */
  62 #define  TRAFFIC_MSG_EVT 560815u        /* rx'd ??? */
  63 #define  TIMEOUT_EVT     560817u        /* link timer expired */
  64
  65 /*
  66  * The following two 'message types' is really just implementation
  67  * data conveniently stored in the message header.
  68  * They must not be considered part of the protocol
  69  */
  70 #define OPEN_MSG   0
  71 #define CLOSED_MSG 1
  72
  73 /*
  74  * State value stored in 'exp_msg_count'
  75  */
  76 #define START_CHANGEOVER 100000u
  77
  78 static void link_handle_out_of_seq_msg(struct tipc_link *l_ptr,
  79                                        struct sk_buff *buf);
  80 static void tipc_link_proto_rcv(struct tipc_link *l_ptr, struct sk_buff *buf);
  81 static int  tipc_link_tunnel_rcv(struct tipc_node *n_ptr,
  82                                  struct sk_buff **buf);
  83 static void link_set_supervision_props(struct tipc_link *l_ptr, u32 tolerance);
  84 static void link_state_event(struct tipc_link *l_ptr, u32 event);
  85 static void link_reset_statistics(struct tipc_link *l_ptr);
  86 static void link_print(struct tipc_link *l_ptr, const char *str);
  87 static void tipc_link_sync_xmit(struct tipc_link *l);
  88 static void tipc_link_sync_rcv(struct tipc_node *n, struct sk_buff *buf);
  89 static int tipc_link_input(struct tipc_link *l, struct sk_buff *buf);
  90 static int tipc_link_prepare_input(struct tipc_link *l, struct sk_buff **buf);
  91
  92 /*
  93  *  Simple link routines
  94  */
  95 static unsigned int align(unsigned int i)
  96 {
  97         return (i + 3) & ~3u;
  98 }
  99
 100 static void link_init_max_pkt(struct tipc_link *l_ptr)
 101 {
 102         struct tipc_bearer *b_ptr;
 103         u32 max_pkt;
 104
 105         rcu_read_lock();
 106         b_ptr = rcu_dereference_rtnl(bearer_list[l_ptr->bearer_id]);
 107         if (!b_ptr) {
 108                 rcu_read_unlock();
 109                 return;
 110         }
 111         max_pkt = (b_ptr->mtu & ~3);
 112         rcu_read_unlock();
 113
 114         if (max_pkt > MAX_MSG_SIZE)
 115                 max_pkt = MAX_MSG_SIZE;
 116
 117         l_ptr->max_pkt_target = max_pkt;
 118         if (l_ptr->max_pkt_target < MAX_PKT_DEFAULT)
 119                 l_ptr->max_pkt = l_ptr->max_pkt_target;
 120         else
 121                 l_ptr->max_pkt = MAX_PKT_DEFAULT;
 122
 123         l_ptr->max_pkt_probes = 0;
 124 }
 125
 126 static u32 link_next_sent(struct tipc_link *l_ptr)
 127 {
 128         if (l_ptr->next_out)
 129                 return buf_seqno(l_ptr->next_out);
 130         return mod(l_ptr->next_out_no);
 131 }
 132
 133 static u32 link_last_sent(struct tipc_link *l_ptr)
 134 {
 135         return mod(link_next_sent(l_ptr) - 1);
 136 }
 137
 138 /*
 139  *  Simple non-static link routines (i.e. referenced outside this file)
 140  */
 141 int tipc_link_is_up(struct tipc_link *l_ptr)
 142 {
 143         if (!l_ptr)
 144                 return 0;
 145         return link_working_working(l_ptr) || link_working_unknown(l_ptr);
 146 }
 147
 148 int tipc_link_is_active(struct tipc_link *l_ptr)
 149 {
 150         return  (l_ptr->owner->active_links[0] == l_ptr) ||
 151                 (l_ptr->owner->active_links[1] == l_ptr);
 152 }
 153
 154 /**
 155  * link_timeout - handle expiration of link timer
 156  * @l_ptr: pointer to link
 157  */
 158 static void link_timeout(struct tipc_link *l_ptr)
 159 {
 160         tipc_node_lock(l_ptr->owner);
 161
 162         /* update counters used in statistical profiling of send traffic */
 163         l_ptr->stats.accu_queue_sz += l_ptr->out_queue_size;
 164         l_ptr->stats.queue_sz_counts++;
 165
 166         if (l_ptr->first_out) {
 167                 struct tipc_msg *msg = buf_msg(l_ptr->first_out);
 168                 u32 length = msg_size(msg);
 169
 170                 if ((msg_user(msg) == MSG_FRAGMENTER) &&
 171                     (msg_type(msg) == FIRST_FRAGMENT)) {
 172                         length = msg_size(msg_get_wrapped(msg));
 173                 }
 174                 if (length) {
 175                         l_ptr->stats.msg_lengths_total += length;
 176                         l_ptr->stats.msg_length_counts++;
 177                         if (length <= 64)
 178                                 l_ptr->stats.msg_length_profile[0]++;
 179                         else if (length <= 256)
 180                                 l_ptr->stats.msg_length_profile[1]++;
 181                         else if (length <= 1024)
 182                                 l_ptr->stats.msg_length_profile[2]++;
 183                         else if (length <= 4096)
 184                                 l_ptr->stats.msg_length_profile[3]++;
 185                         else if (length <= 16384)
 186                                 l_ptr->stats.msg_length_profile[4]++;
 187                         else if (length <= 32768)
 188                                 l_ptr->stats.msg_length_profile[5]++;
 189                         else
 190                                 l_ptr->stats.msg_length_profile[6]++;
 191                 }
 192         }
 193
 194         /* do all other link processing performed on a periodic basis */
 195
 196         link_state_event(l_ptr, TIMEOUT_EVT);
 197
 198         if (l_ptr->next_out)
 199                 tipc_link_push_queue(l_ptr);
 200
 201         tipc_node_unlock(l_ptr->owner);
 202 }
 203
 204 static void link_set_timer(struct tipc_link *l_ptr, u32 time)
 205 {
 206         k_start_timer(&l_ptr->timer, time);
 207 }
 208
 209 /**
 210  * tipc_link_create - create a new link
 211  * @n_ptr: pointer to associated node
 212  * @b_ptr: pointer to associated bearer
 213  * @media_addr: media address to use when sending messages over link
 214  *
 215  * Returns pointer to link.
 216  */
 217 struct tipc_link *tipc_link_create(struct tipc_node *n_ptr,
 218                                    struct tipc_bearer *b_ptr,
 219                                    const struct tipc_media_addr *media_addr)
 220 {
 221         struct tipc_link *l_ptr;
 222         struct tipc_msg *msg;
 223         char *if_name;
 224         char addr_string[16];
 225         u32 peer = n_ptr->addr;
 226
 227         if (n_ptr->link_cnt >= MAX_BEARERS) {
 228                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 229                 pr_err("Attempt to establish %uth link to %s. Max %u allowed.\n",
 230                         n_ptr->link_cnt, addr_string, MAX_BEARERS);
 231                 return NULL;
 232         }
 233
 234         if (n_ptr->links[b_ptr->identity]) {
 235                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 236                 pr_err("Attempt to establish second link on <%s> to %s\n",
 237                        b_ptr->name, addr_string);
 238                 return NULL;
 239         }
 240
 241         l_ptr = kzalloc(sizeof(*l_ptr), GFP_ATOMIC);
 242         if (!l_ptr) {
 243                 pr_warn("Link creation failed, no memory\n");
 244                 return NULL;
 245         }
 246
 247         l_ptr->addr = peer;
 248         if_name = strchr(b_ptr->name, ':') + 1;
 249         sprintf(l_ptr->name, "%u.%u.%u:%s-%u.%u.%u:unknown",
 250                 tipc_zone(tipc_own_addr), tipc_cluster(tipc_own_addr),
 251                 tipc_node(tipc_own_addr),
 252                 if_name,
 253                 tipc_zone(peer), tipc_cluster(peer), tipc_node(peer));
 254                 /* note: peer i/f name is updated by reset/activate message */
 255         memcpy(&l_ptr->media_addr, media_addr, sizeof(*media_addr));
 256         l_ptr->owner = n_ptr;
 257         l_ptr->checkpoint = 1;
 258         l_ptr->peer_session = INVALID_SESSION;
 259         l_ptr->bearer_id = b_ptr->identity;
 260         link_set_supervision_props(l_ptr, b_ptr->tolerance);
 261         l_ptr->state = RESET_UNKNOWN;
 262
 263         l_ptr->pmsg = (struct tipc_msg *)&l_ptr->proto_msg;
 264         msg = l_ptr->pmsg;
 265         tipc_msg_init(msg, LINK_PROTOCOL, RESET_MSG, INT_H_SIZE, l_ptr->addr);
 266         msg_set_size(msg, sizeof(l_ptr->proto_msg));
 267         msg_set_session(msg, (tipc_random & 0xffff));
 268         msg_set_bearer_id(msg, b_ptr->identity);
 269         strcpy((char *)msg_data(msg), if_name);
 270
 271         l_ptr->priority = b_ptr->priority;
 272         tipc_link_set_queue_limits(l_ptr, b_ptr->window);
 273
 274         l_ptr->net_plane = b_ptr->net_plane;
 275         link_init_max_pkt(l_ptr);
 276
 277         l_ptr->next_out_no = 1;
 278         __skb_queue_head_init(&l_ptr->waiting_sks);
 279
 280         link_reset_statistics(l_ptr);
 281
 282         tipc_node_attach_link(n_ptr, l_ptr);
 283
 284         k_init_timer(&l_ptr->timer, (Handler)link_timeout,
 285                      (unsigned long)l_ptr);
 286
 287         link_state_event(l_ptr, STARTING_EVT);
 288
 289         return l_ptr;
 290 }
 291
 292 void tipc_link_delete_list(unsigned int bearer_id, bool shutting_down)
 293 {
 294         struct tipc_link *l_ptr;
 295         struct tipc_node *n_ptr;
 296
 297         rcu_read_lock();
 298         list_for_each_entry_rcu(n_ptr, &tipc_node_list, list) {
 299                 tipc_node_lock(n_ptr);
 300                 l_ptr = n_ptr->links[bearer_id];
 301                 if (l_ptr) {
 302                         tipc_link_reset(l_ptr);
 303                         if (shutting_down || !tipc_node_is_up(n_ptr)) {
 304                                 tipc_node_detach_link(l_ptr->owner, l_ptr);
 305                                 tipc_link_reset_fragments(l_ptr);
 306                                 tipc_node_unlock(n_ptr);
 307
 308                                 /* Nobody else can access this link now: */
 309                                 del_timer_sync(&l_ptr->timer);
 310                                 kfree(l_ptr);
 311                         } else {
 312                                 /* Detach/delete when failover is finished: */
 313                                 l_ptr->flags |= LINK_STOPPED;
 314                                 tipc_node_unlock(n_ptr);
 315                                 del_timer_sync(&l_ptr->timer);
 316                         }
 317                         continue;
 318                 }
 319                 tipc_node_unlock(n_ptr);
 320         }
 321         rcu_read_unlock();
 322 }
 323
 324 /**
 325  * link_schedule_user - schedule user for wakeup after congestion
 326  * @link: congested link
 327  * @oport: sending port
 328  * @chain_sz: size of buffer chain that was attempted sent
 329  * @imp: importance of message attempted sent
 330  * Create pseudo msg to send back to user when congestion abates
 331  */
 332 static bool link_schedule_user(struct tipc_link *link, u32 oport,
 333                                uint chain_sz, uint imp)
 334 {
 335         struct sk_buff *buf;
 336
 337         buf = tipc_msg_create(SOCK_WAKEUP, 0, INT_H_SIZE, 0, tipc_own_addr,
 338                               tipc_own_addr, oport, 0, 0);
 339         if (!buf)
 340                 return false;
 341         TIPC_SKB_CB(buf)->chain_sz = chain_sz;
 342         TIPC_SKB_CB(buf)->chain_imp = imp;
 343         __skb_queue_tail(&link->waiting_sks, buf);
 344         link->stats.link_congs++;
 345         return true;
 346 }
 347
 348 /**
 349  * link_prepare_wakeup - prepare users for wakeup after congestion
 350  * @link: congested link
 351  * Move a number of waiting users, as permitted by available space in
 352  * the send queue, from link wait queue to node wait queue for wakeup
 353  */
 354 static void link_prepare_wakeup(struct tipc_link *link)
 355 {
 356         struct sk_buff_head *wq = &link->waiting_sks;
 357         struct sk_buff *buf;
 358         uint pend_qsz = link->out_queue_size;
 359
 360         for (buf = skb_peek(wq); buf; buf = skb_peek(wq)) {
 361                 if (pend_qsz >= link->queue_limit[TIPC_SKB_CB(buf)->chain_imp])
 362                         break;
 363                 pend_qsz += TIPC_SKB_CB(buf)->chain_sz;
 364                 __skb_queue_tail(&link->owner->waiting_sks, __skb_dequeue(wq));
 365         }
 366 }
 367
 368 /**
 369  * link_release_outqueue - purge link's outbound message queue
 370  * @l_ptr: pointer to link
 371  */
 372 static void link_release_outqueue(struct tipc_link *l_ptr)
 373 {
 374         kfree_skb_list(l_ptr->first_out);
 375         l_ptr->first_out = NULL;
 376         l_ptr->out_queue_size = 0;
 377 }
 378
 379 /**
 380  * tipc_link_reset_fragments - purge link's inbound message fragments queue
 381  * @l_ptr: pointer to link
 382  */
 383 void tipc_link_reset_fragments(struct tipc_link *l_ptr)
 384 {
 385         kfree_skb(l_ptr->reasm_buf);
 386         l_ptr->reasm_buf = NULL;
 387 }
 388
 389 /**
 390  * tipc_link_purge_queues - purge all pkt queues associated with link
 391  * @l_ptr: pointer to link
 392  */
 393 void tipc_link_purge_queues(struct tipc_link *l_ptr)
 394 {
 395         kfree_skb_list(l_ptr->oldest_deferred_in);
 396         kfree_skb_list(l_ptr->first_out);
 397         tipc_link_reset_fragments(l_ptr);
 398         kfree_skb(l_ptr->proto_msg_queue);
 399         l_ptr->proto_msg_queue = NULL;
 400 }
 401
 402 void tipc_link_reset(struct tipc_link *l_ptr)
 403 {
 404         u32 prev_state = l_ptr->state;
 405         u32 checkpoint = l_ptr->next_in_no;
 406         int was_active_link = tipc_link_is_active(l_ptr);
 407         struct tipc_node *owner = l_ptr->owner;
 408
 409         msg_set_session(l_ptr->pmsg, ((msg_session(l_ptr->pmsg) + 1) & 0xffff));
 410
 411         /* Link is down, accept any session */
 412         l_ptr->peer_session = INVALID_SESSION;
 413
 414         /* Prepare for max packet size negotiation */
 415         link_init_max_pkt(l_ptr);
 416
 417         l_ptr->state = RESET_UNKNOWN;
 418
 419         if ((prev_state == RESET_UNKNOWN) || (prev_state == RESET_RESET))
 420                 return;
 421
 422         tipc_node_link_down(l_ptr->owner, l_ptr);
 423         tipc_bearer_remove_dest(l_ptr->bearer_id, l_ptr->addr);
 424
 425         if (was_active_link && tipc_node_active_links(l_ptr->owner)) {
 426                 l_ptr->reset_checkpoint = checkpoint;
 427                 l_ptr->exp_msg_count = START_CHANGEOVER;
 428         }
 429
 430         /* Clean up all queues: */
 431         link_release_outqueue(l_ptr);
 432         kfree_skb(l_ptr->proto_msg_queue);
 433         l_ptr->proto_msg_queue = NULL;
 434         kfree_skb_list(l_ptr->oldest_deferred_in);
 435         if (!skb_queue_empty(&l_ptr->waiting_sks)) {
 436                 skb_queue_splice_init(&l_ptr->waiting_sks, &owner->waiting_sks);
 437                 owner->action_flags |= TIPC_WAKEUP_USERS;
 438         }
 439         l_ptr->retransm_queue_head = 0;
 440         l_ptr->retransm_queue_size = 0;
 441         l_ptr->last_out = NULL;
 442         l_ptr->first_out = NULL;
 443         l_ptr->next_out = NULL;
 444         l_ptr->unacked_window = 0;
 445         l_ptr->checkpoint = 1;
 446         l_ptr->next_out_no = 1;
 447         l_ptr->deferred_inqueue_sz = 0;
 448         l_ptr->oldest_deferred_in = NULL;
 449         l_ptr->newest_deferred_in = NULL;
 450         l_ptr->fsm_msg_cnt = 0;
 451         l_ptr->stale_count = 0;
 452         link_reset_statistics(l_ptr);
 453 }
 454
 455 void tipc_link_reset_list(unsigned int bearer_id)
 456 {
 457         struct tipc_link *l_ptr;
 458         struct tipc_node *n_ptr;
 459
 460         rcu_read_lock();
 461         list_for_each_entry_rcu(n_ptr, &tipc_node_list, list) {
 462                 tipc_node_lock(n_ptr);
 463                 l_ptr = n_ptr->links[bearer_id];
 464                 if (l_ptr)
 465                         tipc_link_reset(l_ptr);
 466                 tipc_node_unlock(n_ptr);
 467         }
 468         rcu_read_unlock();
 469 }
 470
 471 static void link_activate(struct tipc_link *l_ptr)
 472 {
 473         l_ptr->next_in_no = l_ptr->stats.recv_info = 1;
 474         tipc_node_link_up(l_ptr->owner, l_ptr);
 475         tipc_bearer_add_dest(l_ptr->bearer_id, l_ptr->addr);
 476 }
 477
 478 /**
 479  * link_state_event - link finite state machine
 480  * @l_ptr: pointer to link
 481  * @event: state machine event to process
 482  */
 483 static void link_state_event(struct tipc_link *l_ptr, unsigned int event)
 484 {
 485         struct tipc_link *other;
 486         u32 cont_intv = l_ptr->continuity_interval;
 487
 488         if (l_ptr->flags & LINK_STOPPED)
 489                 return;
 490
 491         if (!(l_ptr->flags & LINK_STARTED) && (event != STARTING_EVT))
 492                 return;         /* Not yet. */
 493
 494         /* Check whether changeover is going on */
 495         if (l_ptr->exp_msg_count) {
 496                 if (event == TIMEOUT_EVT)
 497                         link_set_timer(l_ptr, cont_intv);
 498                 return;
 499         }
 500
 501         switch (l_ptr->state) {
 502         case WORKING_WORKING:
 503                 switch (event) {
 504                 case TRAFFIC_MSG_EVT:
 505                 case ACTIVATE_MSG:
 506                         break;
 507                 case TIMEOUT_EVT:
 508                         if (l_ptr->next_in_no != l_ptr->checkpoint) {
 509                                 l_ptr->checkpoint = l_ptr->next_in_no;
 510                                 if (tipc_bclink_acks_missing(l_ptr->owner)) {
 511                                         tipc_link_proto_xmit(l_ptr, STATE_MSG,
 512                                                              0, 0, 0, 0, 0);
 513                                         l_ptr->fsm_msg_cnt++;
 514                                 } else if (l_ptr->max_pkt < l_ptr->max_pkt_target) {
 515                                         tipc_link_proto_xmit(l_ptr, STATE_MSG,
 516                                                              1, 0, 0, 0, 0);
 517                                         l_ptr->fsm_msg_cnt++;
 518                                 }
 519                                 link_set_timer(l_ptr, cont_intv);
 520                                 break;
 521                         }
 522                         l_ptr->state = WORKING_UNKNOWN;
 523                         l_ptr->fsm_msg_cnt = 0;
 524                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
 525                         l_ptr->fsm_msg_cnt++;
 526                         link_set_timer(l_ptr, cont_intv / 4);
 527                         break;
 528                 case RESET_MSG:
 529                         pr_info("%s<%s>, requested by peer\n", link_rst_msg,
 530                                 l_ptr->name);
 531                         tipc_link_reset(l_ptr);
 532                         l_ptr->state = RESET_RESET;
 533                         l_ptr->fsm_msg_cnt = 0;
 534                         tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
 535                                              0, 0, 0, 0, 0);
 536                         l_ptr->fsm_msg_cnt++;
 537                         link_set_timer(l_ptr, cont_intv);
 538                         break;
 539                 default:
 540                         pr_err("%s%u in WW state\n", link_unk_evt, event);
 541                 }
 542                 break;
 543         case WORKING_UNKNOWN:
 544                 switch (event) {
 545                 case TRAFFIC_MSG_EVT:
 546                 case ACTIVATE_MSG:
 547                         l_ptr->state = WORKING_WORKING;
 548                         l_ptr->fsm_msg_cnt = 0;
 549                         link_set_timer(l_ptr, cont_intv);
 550                         break;
 551                 case RESET_MSG:
 552                         pr_info("%s<%s>, requested by peer while probing\n",
 553                                 link_rst_msg, l_ptr->name);
 554                         tipc_link_reset(l_ptr);
 555                         l_ptr->state = RESET_RESET;
 556                         l_ptr->fsm_msg_cnt = 0;
 557                         tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
 558                                              0, 0, 0, 0, 0);
 559                         l_ptr->fsm_msg_cnt++;
 560                         link_set_timer(l_ptr, cont_intv);
 561                         break;
 562                 case TIMEOUT_EVT:
 563                         if (l_ptr->next_in_no != l_ptr->checkpoint) {
 564                                 l_ptr->state = WORKING_WORKING;
 565                                 l_ptr->fsm_msg_cnt = 0;
 566                                 l_ptr->checkpoint = l_ptr->next_in_no;
 567                                 if (tipc_bclink_acks_missing(l_ptr->owner)) {
 568                                         tipc_link_proto_xmit(l_ptr, STATE_MSG,
 569                                                              0, 0, 0, 0, 0);
 570                                         l_ptr->fsm_msg_cnt++;
 571                                 }
 572                                 link_set_timer(l_ptr, cont_intv);
 573                         } else if (l_ptr->fsm_msg_cnt < l_ptr->abort_limit) {
 574                                 tipc_link_proto_xmit(l_ptr, STATE_MSG,
 575                                                      1, 0, 0, 0, 0);
 576                                 l_ptr->fsm_msg_cnt++;
 577                                 link_set_timer(l_ptr, cont_intv / 4);
 578                         } else {        /* Link has failed */
 579                                 pr_warn("%s<%s>, peer not responding\n",
 580                                         link_rst_msg, l_ptr->name);
 581                                 tipc_link_reset(l_ptr);
 582                                 l_ptr->state = RESET_UNKNOWN;
 583                                 l_ptr->fsm_msg_cnt = 0;
 584                                 tipc_link_proto_xmit(l_ptr, RESET_MSG,
 585                                                      0, 0, 0, 0, 0);
 586                                 l_ptr->fsm_msg_cnt++;
 587                                 link_set_timer(l_ptr, cont_intv);
 588                         }
 589                         break;
 590                 default:
 591                         pr_err("%s%u in WU state\n", link_unk_evt, event);
 592                 }
 593                 break;
 594         case RESET_UNKNOWN:
 595                 switch (event) {
 596                 case TRAFFIC_MSG_EVT:
 597                         break;
 598                 case ACTIVATE_MSG:
 599                         other = l_ptr->owner->active_links[0];
 600                         if (other && link_working_unknown(other))
 601                                 break;
 602                         l_ptr->state = WORKING_WORKING;
 603                         l_ptr->fsm_msg_cnt = 0;
 604                         link_activate(l_ptr);
 605                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
 606                         l_ptr->fsm_msg_cnt++;
 607                         if (l_ptr->owner->working_links == 1)
 608                                 tipc_link_sync_xmit(l_ptr);
 609                         link_set_timer(l_ptr, cont_intv);
 610                         break;
 611                 case RESET_MSG:
 612                         l_ptr->state = RESET_RESET;
 613                         l_ptr->fsm_msg_cnt = 0;
 614                         tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
 615                                              1, 0, 0, 0, 0);
 616                         l_ptr->fsm_msg_cnt++;
 617                         link_set_timer(l_ptr, cont_intv);
 618                         break;
 619                 case STARTING_EVT:
 620                         l_ptr->flags |= LINK_STARTED;
 621                         /* fall through */
 622                 case TIMEOUT_EVT:
 623                         tipc_link_proto_xmit(l_ptr, RESET_MSG, 0, 0, 0, 0, 0);
 624                         l_ptr->fsm_msg_cnt++;
 625                         link_set_timer(l_ptr, cont_intv);
 626                         break;
 627                 default:
 628                         pr_err("%s%u in RU state\n", link_unk_evt, event);
 629                 }
 630                 break;
 631         case RESET_RESET:
 632                 switch (event) {
 633                 case TRAFFIC_MSG_EVT:
 634                 case ACTIVATE_MSG:
 635                         other = l_ptr->owner->active_links[0];
 636                         if (other && link_working_unknown(other))
 637                                 break;
 638                         l_ptr->state = WORKING_WORKING;
 639                         l_ptr->fsm_msg_cnt = 0;
 640                         link_activate(l_ptr);
 641                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
 642                         l_ptr->fsm_msg_cnt++;
 643                         if (l_ptr->owner->working_links == 1)
 644                                 tipc_link_sync_xmit(l_ptr);
 645                         link_set_timer(l_ptr, cont_intv);
 646                         break;
 647                 case RESET_MSG:
 648                         break;
 649                 case TIMEOUT_EVT:
 650                         tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
 651                                              0, 0, 0, 0, 0);
 652                         l_ptr->fsm_msg_cnt++;
 653                         link_set_timer(l_ptr, cont_intv);
 654                         break;
 655                 default:
 656                         pr_err("%s%u in RR state\n", link_unk_evt, event);
 657                 }
 658                 break;
 659         default:
 660                 pr_err("Unknown link state %u/%u\n", l_ptr->state, event);
 661         }
 662 }
 663
 664 /* tipc_link_cong: determine return value and how to treat the
 665  * sent buffer during link congestion.
 666  * - For plain, errorless user data messages we keep the buffer and
 667  *   return -ELINKONG.
 668  * - For all other messages we discard the buffer and return -EHOSTUNREACH
 669  * - For TIPC internal messages we also reset the link
 670  */
 671 static int tipc_link_cong(struct tipc_link *link, struct sk_buff *buf)
 672 {
 673         struct tipc_msg *msg = buf_msg(buf);
 674         uint imp = tipc_msg_tot_importance(msg);
 675         u32 oport = msg_tot_origport(msg);
 676
 677         if (unlikely(imp > TIPC_CRITICAL_IMPORTANCE)) {
 678                 pr_warn("%s<%s>, send queue full", link_rst_msg, link->name);
 679                 tipc_link_reset(link);
 680                 goto drop;
 681         }
 682         if (unlikely(msg_errcode(msg)))
 683                 goto drop;
 684         if (unlikely(msg_reroute_cnt(msg)))
 685                 goto drop;
 686         if (TIPC_SKB_CB(buf)->wakeup_pending)
 687                 return -ELINKCONG;
 688         if (link_schedule_user(link, oport, TIPC_SKB_CB(buf)->chain_sz, imp))
 689                 return -ELINKCONG;
 690 drop:
 691         kfree_skb_list(buf);
 692         return -EHOSTUNREACH;
 693 }
 694
 695 /**
 696  * __tipc_link_xmit(): same as tipc_link_xmit, but destlink is known & locked
 697  * @link: link to use
 698  * @buf: chain of buffers containing message
 699  * Consumes the buffer chain, except when returning -ELINKCONG
 700  * Returns 0 if success, otherwise errno: -ELINKCONG, -EMSGSIZE (plain socket
 701  * user data messages) or -EHOSTUNREACH (all other messages/senders)
 702  * Only the socket functions tipc_send_stream() and tipc_send_packet() need
 703  * to act on the return value, since they may need to do more send attempts.
 704  */
 705 int __tipc_link_xmit(struct tipc_link *link, struct sk_buff *buf)
 706 {
 707         struct tipc_msg *msg = buf_msg(buf);
 708         uint psz = msg_size(msg);
 709         uint qsz = link->out_queue_size;
 710         uint sndlim = link->queue_limit[0];
 711         uint imp = tipc_msg_tot_importance(msg);
 712         uint mtu = link->max_pkt;
 713         uint ack = mod(link->next_in_no - 1);
 714         uint seqno = link->next_out_no;
 715         uint bc_last_in = link->owner->bclink.last_in;
 716         struct tipc_media_addr *addr = &link->media_addr;
 717         struct sk_buff *next = buf->next;
 718
 719         /* Match queue limits against msg importance: */
 720         if (unlikely(qsz >= link->queue_limit[imp]))
 721                 return tipc_link_cong(link, buf);
 722
 723         /* Has valid packet limit been used ? */
 724         if (unlikely(psz > mtu)) {
 725                 kfree_skb_list(buf);
 726                 return -EMSGSIZE;
 727         }
 728
 729         /* Prepare each packet for sending, and add to outqueue: */
 730         while (buf) {
 731                 next = buf->next;
 732                 msg = buf_msg(buf);
 733                 msg_set_word(msg, 2, ((ack << 16) | mod(seqno)));
 734                 msg_set_bcast_ack(msg, bc_last_in);
 735
 736                 if (!link->first_out) {
 737                         link->first_out = buf;
 738                 } else if (qsz < sndlim) {
 739                         link->last_out->next = buf;
 740                 } else if (tipc_msg_bundle(link->last_out, buf, mtu)) {
 741                         link->stats.sent_bundled++;
 742                         buf = next;
 743                         next = buf->next;
 744                         continue;
 745                 } else if (tipc_msg_make_bundle(&buf, mtu, link->addr)) {
 746                         link->stats.sent_bundled++;
 747                         link->stats.sent_bundles++;
 748                         link->last_out->next = buf;
 749                         if (!link->next_out)
 750                                 link->next_out = buf;
 751                 } else {
 752                         link->last_out->next = buf;
 753                         if (!link->next_out)
 754                                 link->next_out = buf;
 755                 }
 756
 757                 /* Send packet if possible: */
 758                 if (likely(++qsz <= sndlim)) {
 759                         tipc_bearer_send(link->bearer_id, buf, addr);
 760                         link->next_out = next;
 761                         link->unacked_window = 0;
 762                 }
 763                 seqno++;
 764                 link->last_out = buf;
 765                 buf = next;
 766         }
 767         link->next_out_no = seqno;
 768         link->out_queue_size = qsz;
 769         return 0;
 770 }
 771
 772 /**
 773  * tipc_link_xmit() is the general link level function for message sending
 774  * @buf: chain of buffers containing message
 775  * @dsz: amount of user data to be sent
 776  * @dnode: address of destination node
 777  * @selector: a number used for deterministic link selection
 778  * Consumes the buffer chain, except when returning -ELINKCONG
 779  * Returns 0 if success, otherwise errno: -ELINKCONG,-EHOSTUNREACH,-EMSGSIZE
 780  */
 781 int tipc_link_xmit(struct sk_buff *buf, u32 dnode, u32 selector)
 782 {
 783         struct tipc_link *link = NULL;
 784         struct tipc_node *node;
 785         int rc = -EHOSTUNREACH;
 786
 787         node = tipc_node_find(dnode);
 788         if (node) {
 789                 tipc_node_lock(node);
 790                 link = node->active_links[selector & 1];
 791                 if (link)
 792                         rc = __tipc_link_xmit(link, buf);
 793                 tipc_node_unlock(node);
 794         }
 795
 796         if (link)
 797                 return rc;
 798
 799         if (likely(in_own_node(dnode)))
 800                 return tipc_sk_rcv(buf);
 801
 802         kfree_skb_list(buf);
 803         return rc;
 804 }
 805
 806 /*
 807  * tipc_link_sync_xmit - synchronize broadcast link endpoints.
 808  *
 809  * Give a newly added peer node the sequence number where it should
 810  * start receiving and acking broadcast packets.
 811  *
 812  * Called with node locked
 813  */
 814 static void tipc_link_sync_xmit(struct tipc_link *link)
 815 {
 816         struct sk_buff *buf;
 817         struct tipc_msg *msg;
 818
 819         buf = tipc_buf_acquire(INT_H_SIZE);
 820         if (!buf)
 821                 return;
 822
 823         msg = buf_msg(buf);
 824         tipc_msg_init(msg, BCAST_PROTOCOL, STATE_MSG, INT_H_SIZE, link->addr);
 825         msg_set_last_bcast(msg, link->owner->bclink.acked);
 826         __tipc_link_xmit(link, buf);
 827 }
 828
 829 /*
 830  * tipc_link_sync_rcv - synchronize broadcast link endpoints.
 831  * Receive the sequence number where we should start receiving and
 832  * acking broadcast packets from a newly added peer node, and open
 833  * up for reception of such packets.
 834  *
 835  * Called with node locked
 836  */
 837 static void tipc_link_sync_rcv(struct tipc_node *n, struct sk_buff *buf)
 838 {
 839         struct tipc_msg *msg = buf_msg(buf);
 840
 841         n->bclink.last_sent = n->bclink.last_in = msg_last_bcast(msg);
 842         n->bclink.recv_permitted = true;
 843         kfree_skb(buf);
 844 }
 845
 846 /*
 847  * tipc_link_push_packet: Push one unsent packet to the media
 848  */
 849 static u32 tipc_link_push_packet(struct tipc_link *l_ptr)
 850 {
 851         struct sk_buff *buf = l_ptr->first_out;
 852         u32 r_q_size = l_ptr->retransm_queue_size;
 853         u32 r_q_head = l_ptr->retransm_queue_head;
 854
 855         /* Step to position where retransmission failed, if any,    */
 856         /* consider that buffers may have been released in meantime */
 857         if (r_q_size && buf) {
 858                 u32 last = lesser(mod(r_q_head + r_q_size),
 859                                   link_last_sent(l_ptr));
 860                 u32 first = buf_seqno(buf);
 861
 862                 while (buf && less(first, r_q_head)) {
 863                         first = mod(first + 1);
 864                         buf = buf->next;
 865                 }
 866                 l_ptr->retransm_queue_head = r_q_head = first;
 867                 l_ptr->retransm_queue_size = r_q_size = mod(last - first);
 868         }
 869
 870         /* Continue retransmission now, if there is anything: */
 871         if (r_q_size && buf) {
 872                 msg_set_ack(buf_msg(buf), mod(l_ptr->next_in_no - 1));
 873                 msg_set_bcast_ack(buf_msg(buf), l_ptr->owner->bclink.last_in);
 874                 tipc_bearer_send(l_ptr->bearer_id, buf, &l_ptr->media_addr);
 875                 l_ptr->retransm_queue_head = mod(++r_q_head);
 876                 l_ptr->retransm_queue_size = --r_q_size;
 877                 l_ptr->stats.retransmitted++;
 878                 return 0;
 879         }
 880
 881         /* Send deferred protocol message, if any: */
 882         buf = l_ptr->proto_msg_queue;
 883         if (buf) {
 884                 msg_set_ack(buf_msg(buf), mod(l_ptr->next_in_no - 1));
 885                 msg_set_bcast_ack(buf_msg(buf), l_ptr->owner->bclink.last_in);
 886                 tipc_bearer_send(l_ptr->bearer_id, buf, &l_ptr->media_addr);
 887                 l_ptr->unacked_window = 0;
 888                 kfree_skb(buf);
 889                 l_ptr->proto_msg_queue = NULL;
 890                 return 0;
 891         }
 892
 893         /* Send one deferred data message, if send window not full: */
 894         buf = l_ptr->next_out;
 895         if (buf) {
 896                 struct tipc_msg *msg = buf_msg(buf);
 897                 u32 next = msg_seqno(msg);
 898                 u32 first = buf_seqno(l_ptr->first_out);
 899
 900                 if (mod(next - first) < l_ptr->queue_limit[0]) {
 901                         msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
 902                         msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
 903                         tipc_bearer_send(l_ptr->bearer_id, buf,
 904                                          &l_ptr->media_addr);
 905                         if (msg_user(msg) == MSG_BUNDLER)
 906                                 msg_set_type(msg, BUNDLE_CLOSED);
 907                         l_ptr->next_out = buf->next;
 908                         return 0;
 909                 }
 910         }
 911         return 1;
 912 }
 913
 914 /*
 915  * push_queue(): push out the unsent messages of a link where
 916  *               congestion has abated. Node is locked
 917  */
 918 void tipc_link_push_queue(struct tipc_link *l_ptr)
 919 {
 920         u32 res;
 921
 922         do {
 923                 res = tipc_link_push_packet(l_ptr);
 924         } while (!res);
 925 }
 926
 927 void tipc_link_reset_all(struct tipc_node *node)
 928 {
 929         char addr_string[16];
 930         u32 i;
 931
 932         tipc_node_lock(node);
 933
 934         pr_warn("Resetting all links to %s\n",
 935                 tipc_addr_string_fill(addr_string, node->addr));
 936
 937         for (i = 0; i < MAX_BEARERS; i++) {
 938                 if (node->links[i]) {
 939                         link_print(node->links[i], "Resetting link\n");
 940                         tipc_link_reset(node->links[i]);
 941                 }
 942         }
 943
 944         tipc_node_unlock(node);
 945 }
 946
 947 static void link_retransmit_failure(struct tipc_link *l_ptr,
 948                                     struct sk_buff *buf)
 949 {
 950         struct tipc_msg *msg = buf_msg(buf);
 951
 952         pr_warn("Retransmission failure on link <%s>\n", l_ptr->name);
 953
 954         if (l_ptr->addr) {
 955                 /* Handle failure on standard link */
 956                 link_print(l_ptr, "Resetting link\n");
 957                 tipc_link_reset(l_ptr);
 958
 959         } else {
 960                 /* Handle failure on broadcast link */
 961                 struct tipc_node *n_ptr;
 962                 char addr_string[16];
 963
 964                 pr_info("Msg seq number: %u,  ", msg_seqno(msg));
 965                 pr_cont("Outstanding acks: %lu\n",
 966                         (unsigned long) TIPC_SKB_CB(buf)->handle);
 967
 968                 n_ptr = tipc_bclink_retransmit_to();
 969                 tipc_node_lock(n_ptr);
 970
 971                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 972                 pr_info("Broadcast link info for %s\n", addr_string);
 973                 pr_info("Reception permitted: %d,  Acked: %u\n",
 974                         n_ptr->bclink.recv_permitted,
 975                         n_ptr->bclink.acked);
 976                 pr_info("Last in: %u,  Oos state: %u,  Last sent: %u\n",
 977                         n_ptr->bclink.last_in,
 978                         n_ptr->bclink.oos_state,
 979                         n_ptr->bclink.last_sent);
 980
 981                 tipc_node_unlock(n_ptr);
 982
 983                 tipc_bclink_set_flags(TIPC_BCLINK_RESET);
 984                 l_ptr->stale_count = 0;
 985         }
 986 }
 987
 988 void tipc_link_retransmit(struct tipc_link *l_ptr, struct sk_buff *buf,
 989                           u32 retransmits)
 990 {
 991         struct tipc_msg *msg;
 992
 993         if (!buf)
 994                 return;
 995
 996         msg = buf_msg(buf);
 997
 998         /* Detect repeated retransmit failures */
 999         if (l_ptr->last_retransmitted == msg_seqno(msg)) {
1000                 if (++l_ptr->stale_count > 100) {
1001                         link_retransmit_failure(l_ptr, buf);
1002                         return;
1003                 }
1004         } else {
1005                 l_ptr->last_retransmitted = msg_seqno(msg);
1006                 l_ptr->stale_count = 1;
1007         }
1008
1009         while (retransmits && (buf != l_ptr->next_out) && buf) {
1010                 msg = buf_msg(buf);
1011                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1012                 msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1013                 tipc_bearer_send(l_ptr->bearer_id, buf, &l_ptr->media_addr);
1014                 buf = buf->next;
1015                 retransmits--;
1016                 l_ptr->stats.retransmitted++;
1017         }
1018
1019         l_ptr->retransm_queue_head = l_ptr->retransm_queue_size = 0;
1020 }
1021
1022 /**
1023  * link_insert_deferred_queue - insert deferred messages back into receive chain
1024  */
1025 static struct sk_buff *link_insert_deferred_queue(struct tipc_link *l_ptr,
1026                                                   struct sk_buff *buf)
1027 {
1028         u32 seq_no;
1029
1030         if (l_ptr->oldest_deferred_in == NULL)
1031                 return buf;
1032
1033         seq_no = buf_seqno(l_ptr->oldest_deferred_in);
1034         if (seq_no == mod(l_ptr->next_in_no)) {
1035                 l_ptr->newest_deferred_in->next = buf;
1036                 buf = l_ptr->oldest_deferred_in;
1037                 l_ptr->oldest_deferred_in = NULL;
1038                 l_ptr->deferred_inqueue_sz = 0;
1039         }
1040         return buf;
1041 }
1042
1043 /**
1044  * link_recv_buf_validate - validate basic format of received message
1045  *
1046  * This routine ensures a TIPC message has an acceptable header, and at least
1047  * as much data as the header indicates it should.  The routine also ensures
1048  * that the entire message header is stored in the main fragment of the message
1049  * buffer, to simplify future access to message header fields.
1050  *
1051  * Note: Having extra info present in the message header or data areas is OK.
1052  * TIPC will ignore the excess, under the assumption that it is optional info
1053  * introduced by a later release of the protocol.
1054  */
1055 static int link_recv_buf_validate(struct sk_buff *buf)
1056 {
1057         static u32 min_data_hdr_size[8] = {
1058                 SHORT_H_SIZE, MCAST_H_SIZE, NAMED_H_SIZE, BASIC_H_SIZE,
1059                 MAX_H_SIZE, MAX_H_SIZE, MAX_H_SIZE, MAX_H_SIZE
1060                 };
1061
1062         struct tipc_msg *msg;
1063         u32 tipc_hdr[2];
1064         u32 size;
1065         u32 hdr_size;
1066         u32 min_hdr_size;
1067
1068         /* If this packet comes from the defer queue, the skb has already
1069          * been validated
1070          */
1071         if (unlikely(TIPC_SKB_CB(buf)->deferred))
1072                 return 1;
1073
1074         if (unlikely(buf->len < MIN_H_SIZE))
1075                 return 0;
1076
1077         msg = skb_header_pointer(buf, 0, sizeof(tipc_hdr), tipc_hdr);
1078         if (msg == NULL)
1079                 return 0;
1080
1081         if (unlikely(msg_version(msg) != TIPC_VERSION))
1082                 return 0;
1083
1084         size = msg_size(msg);
1085         hdr_size = msg_hdr_sz(msg);
1086         min_hdr_size = msg_isdata(msg) ?
1087                 min_data_hdr_size[msg_type(msg)] : INT_H_SIZE;
1088
1089         if (unlikely((hdr_size < min_hdr_size) ||
1090                      (size < hdr_size) ||
1091                      (buf->len < size) ||
1092                      (size - hdr_size > TIPC_MAX_USER_MSG_SIZE)))
1093                 return 0;
1094
1095         return pskb_may_pull(buf, hdr_size);
1096 }
1097
1098 /**
1099  * tipc_rcv - process TIPC packets/messages arriving from off-node
1100  * @head: pointer to message buffer chain
1101  * @b_ptr: pointer to bearer message arrived on
1102  *
1103  * Invoked with no locks held.  Bearer pointer must point to a valid bearer
1104  * structure (i.e. cannot be NULL), but bearer can be inactive.
1105  */
1106 void tipc_rcv(struct sk_buff *head, struct tipc_bearer *b_ptr)
1107 {
1108         while (head) {
1109                 struct tipc_node *n_ptr;
1110                 struct tipc_link *l_ptr;
1111                 struct sk_buff *crs;
1112                 struct sk_buff *buf = head;
1113                 struct tipc_msg *msg;
1114                 u32 seq_no;
1115                 u32 ackd;
1116                 u32 released = 0;
1117
1118                 head = head->next;
1119                 buf->next = NULL;
1120
1121                 /* Ensure message is well-formed */
1122                 if (unlikely(!link_recv_buf_validate(buf)))
1123                         goto discard;
1124
1125                 /* Ensure message data is a single contiguous unit */
1126                 if (unlikely(skb_linearize(buf)))
1127                         goto discard;
1128
1129                 /* Handle arrival of a non-unicast link message */
1130                 msg = buf_msg(buf);
1131
1132                 if (unlikely(msg_non_seq(msg))) {
1133                         if (msg_user(msg) ==  LINK_CONFIG)
1134                                 tipc_disc_rcv(buf, b_ptr);
1135                         else
1136                                 tipc_bclink_rcv(buf);
1137                         continue;
1138                 }
1139
1140                 /* Discard unicast link messages destined for another node */
1141                 if (unlikely(!msg_short(msg) &&
1142                              (msg_destnode(msg) != tipc_own_addr)))
1143                         goto discard;
1144
1145                 /* Locate neighboring node that sent message */
1146                 n_ptr = tipc_node_find(msg_prevnode(msg));
1147                 if (unlikely(!n_ptr))
1148                         goto discard;
1149                 tipc_node_lock(n_ptr);
1150
1151                 /* Locate unicast link endpoint that should handle message */
1152                 l_ptr = n_ptr->links[b_ptr->identity];
1153                 if (unlikely(!l_ptr))
1154                         goto unlock_discard;
1155
1156                 /* Verify that communication with node is currently allowed */
1157                 if ((n_ptr->action_flags & TIPC_WAIT_PEER_LINKS_DOWN) &&
1158                     msg_user(msg) == LINK_PROTOCOL &&
1159                     (msg_type(msg) == RESET_MSG ||
1160                     msg_type(msg) == ACTIVATE_MSG) &&
1161                     !msg_redundant_link(msg))
1162                         n_ptr->action_flags &= ~TIPC_WAIT_PEER_LINKS_DOWN;
1163
1164                 if (tipc_node_blocked(n_ptr))
1165                         goto unlock_discard;
1166
1167                 /* Validate message sequence number info */
1168                 seq_no = msg_seqno(msg);
1169                 ackd = msg_ack(msg);
1170
1171                 /* Release acked messages */
1172                 if (n_ptr->bclink.recv_permitted)
1173                         tipc_bclink_acknowledge(n_ptr, msg_bcast_ack(msg));
1174
1175                 crs = l_ptr->first_out;
1176                 while ((crs != l_ptr->next_out) &&
1177                        less_eq(buf_seqno(crs), ackd)) {
1178                         struct sk_buff *next = crs->next;
1179                         kfree_skb(crs);
1180                         crs = next;
1181                         released++;
1182                 }
1183                 if (released) {
1184                         l_ptr->first_out = crs;
1185                         l_ptr->out_queue_size -= released;
1186                 }
1187
1188                 /* Try sending any messages link endpoint has pending */
1189                 if (unlikely(l_ptr->next_out))
1190                         tipc_link_push_queue(l_ptr);
1191
1192                 if (released && !skb_queue_empty(&l_ptr->waiting_sks)) {
1193                         link_prepare_wakeup(l_ptr);
1194                         l_ptr->owner->action_flags |= TIPC_WAKEUP_USERS;
1195                 }
1196
1197                 /* Process the incoming packet */
1198                 if (unlikely(!link_working_working(l_ptr))) {
1199                         if (msg_user(msg) == LINK_PROTOCOL) {
1200                                 tipc_link_proto_rcv(l_ptr, buf);
1201                                 head = link_insert_deferred_queue(l_ptr, head);
1202                                 tipc_node_unlock(n_ptr);
1203                                 continue;
1204                         }
1205
1206                         /* Traffic message. Conditionally activate link */
1207                         link_state_event(l_ptr, TRAFFIC_MSG_EVT);
1208
1209                         if (link_working_working(l_ptr)) {
1210                                 /* Re-insert buffer in front of queue */
1211                                 buf->next = head;
1212                                 head = buf;
1213                                 tipc_node_unlock(n_ptr);
1214                                 continue;
1215                         }
1216                         goto unlock_discard;
1217                 }
1218
1219                 /* Link is now in state WORKING_WORKING */
1220                 if (unlikely(seq_no != mod(l_ptr->next_in_no))) {
1221                         link_handle_out_of_seq_msg(l_ptr, buf);
1222                         head = link_insert_deferred_queue(l_ptr, head);
1223                         tipc_node_unlock(n_ptr);
1224                         continue;
1225                 }
1226                 l_ptr->next_in_no++;
1227                 if (unlikely(l_ptr->oldest_deferred_in))
1228                         head = link_insert_deferred_queue(l_ptr, head);
1229
1230                 if (unlikely(++l_ptr->unacked_window >= TIPC_MIN_LINK_WIN)) {
1231                         l_ptr->stats.sent_acks++;
1232                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
1233                 }
1234
1235                 if (tipc_link_prepare_input(l_ptr, &buf)) {
1236                         tipc_node_unlock(n_ptr);
1237                         continue;
1238                 }
1239                 tipc_node_unlock(n_ptr);
1240                 msg = buf_msg(buf);
1241                 if (tipc_link_input(l_ptr, buf) != 0)
1242                         goto discard;
1243                 continue;
1244 unlock_discard:
1245                 tipc_node_unlock(n_ptr);
1246 discard:
1247                 kfree_skb(buf);
1248         }
1249 }
1250
1251 /**
1252  * tipc_link_prepare_input - process TIPC link messages
1253  *
1254  * returns nonzero if the message was consumed
1255  *
1256  * Node lock must be held
1257  */
1258 static int tipc_link_prepare_input(struct tipc_link *l, struct sk_buff **buf)
1259 {
1260         struct tipc_node *n;
1261         struct tipc_msg *msg;
1262         int res = -EINVAL;
1263
1264         n = l->owner;
1265         msg = buf_msg(*buf);
1266         switch (msg_user(msg)) {
1267         case CHANGEOVER_PROTOCOL:
1268                 if (tipc_link_tunnel_rcv(n, buf))
1269                         res = 0;
1270                 break;
1271         case MSG_FRAGMENTER:
1272                 l->stats.recv_fragments++;
1273                 if (tipc_buf_append(&l->reasm_buf, buf)) {
1274                         l->stats.recv_fragmented++;
1275                         res = 0;
1276                 } else if (!l->reasm_buf) {
1277                         tipc_link_reset(l);
1278                 }
1279                 break;
1280         case MSG_BUNDLER:
1281                 l->stats.recv_bundles++;
1282                 l->stats.recv_bundled += msg_msgcnt(msg);
1283                 res = 0;
1284                 break;
1285         case NAME_DISTRIBUTOR:
1286                 n->bclink.recv_permitted = true;
1287                 res = 0;
1288                 break;
1289         case BCAST_PROTOCOL:
1290                 tipc_link_sync_rcv(n, *buf);
1291                 break;
1292         default:
1293                 res = 0;
1294         }
1295         return res;
1296 }
1297 /**
1298  * tipc_link_input - Deliver message too higher layers
1299  */
1300 static int tipc_link_input(struct tipc_link *l, struct sk_buff *buf)
1301 {
1302         struct tipc_msg *msg = buf_msg(buf);
1303         int res = 0;
1304
1305         switch (msg_user(msg)) {
1306         case TIPC_LOW_IMPORTANCE:
1307         case TIPC_MEDIUM_IMPORTANCE:
1308         case TIPC_HIGH_IMPORTANCE:
1309         case TIPC_CRITICAL_IMPORTANCE:
1310         case CONN_MANAGER:
1311                 tipc_sk_rcv(buf);
1312                 break;
1313         case NAME_DISTRIBUTOR:
1314                 tipc_named_rcv(buf);
1315                 break;
1316         case MSG_BUNDLER:
1317                 tipc_link_bundle_rcv(buf);
1318                 break;
1319         default:
1320                 res = -EINVAL;
1321         }
1322         return res;
1323 }
1324
1325 /**
1326  * tipc_link_defer_pkt - Add out-of-sequence message to deferred reception queue
1327  *
1328  * Returns increase in queue length (i.e. 0 or 1)
1329  */
1330 u32 tipc_link_defer_pkt(struct sk_buff **head, struct sk_buff **tail,
1331                         struct sk_buff *buf)
1332 {
1333         struct sk_buff *queue_buf;
1334         struct sk_buff **prev;
1335         u32 seq_no = buf_seqno(buf);
1336
1337         buf->next = NULL;
1338
1339         /* Empty queue ? */
1340         if (*head == NULL) {
1341                 *head = *tail = buf;
1342                 return 1;
1343         }
1344
1345         /* Last ? */
1346         if (less(buf_seqno(*tail), seq_no)) {
1347                 (*tail)->next = buf;
1348                 *tail = buf;
1349                 return 1;
1350         }
1351
1352         /* Locate insertion point in queue, then insert; discard if duplicate */
1353         prev = head;
1354         queue_buf = *head;
1355         for (;;) {
1356                 u32 curr_seqno = buf_seqno(queue_buf);
1357
1358                 if (seq_no == curr_seqno) {
1359                         kfree_skb(buf);
1360                         return 0;
1361                 }
1362
1363                 if (less(seq_no, curr_seqno))
1364                         break;
1365
1366                 prev = &queue_buf->next;
1367                 queue_buf = queue_buf->next;
1368         }
1369
1370         buf->next = queue_buf;
1371         *prev = buf;
1372         return 1;
1373 }
1374
1375 /*
1376  * link_handle_out_of_seq_msg - handle arrival of out-of-sequence packet
1377  */
1378 static void link_handle_out_of_seq_msg(struct tipc_link *l_ptr,
1379                                        struct sk_buff *buf)
1380 {
1381         u32 seq_no = buf_seqno(buf);
1382
1383         if (likely(msg_user(buf_msg(buf)) == LINK_PROTOCOL)) {
1384                 tipc_link_proto_rcv(l_ptr, buf);
1385                 return;
1386         }
1387
1388         /* Record OOS packet arrival (force mismatch on next timeout) */
1389         l_ptr->checkpoint--;
1390
1391         /*
1392          * Discard packet if a duplicate; otherwise add it to deferred queue
1393          * and notify peer of gap as per protocol specification
1394          */
1395         if (less(seq_no, mod(l_ptr->next_in_no))) {
1396                 l_ptr->stats.duplicates++;
1397                 kfree_skb(buf);
1398                 return;
1399         }
1400
1401         if (tipc_link_defer_pkt(&l_ptr->oldest_deferred_in,
1402                                 &l_ptr->newest_deferred_in, buf)) {
1403                 l_ptr->deferred_inqueue_sz++;
1404                 l_ptr->stats.deferred_recv++;
1405                 TIPC_SKB_CB(buf)->deferred = true;
1406                 if ((l_ptr->deferred_inqueue_sz % 16) == 1)
1407                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
1408         } else
1409                 l_ptr->stats.duplicates++;
1410 }
1411
1412 /*
1413  * Send protocol message to the other endpoint.
1414  */
1415 void tipc_link_proto_xmit(struct tipc_link *l_ptr, u32 msg_typ, int probe_msg,
1416                           u32 gap, u32 tolerance, u32 priority, u32 ack_mtu)
1417 {
1418         struct sk_buff *buf = NULL;
1419         struct tipc_msg *msg = l_ptr->pmsg;
1420         u32 msg_size = sizeof(l_ptr->proto_msg);
1421         int r_flag;
1422
1423         /* Discard any previous message that was deferred due to congestion */
1424         if (l_ptr->proto_msg_queue) {
1425                 kfree_skb(l_ptr->proto_msg_queue);
1426                 l_ptr->proto_msg_queue = NULL;
1427         }
1428
1429         /* Don't send protocol message during link changeover */
1430         if (l_ptr->exp_msg_count)
1431                 return;
1432
1433         /* Abort non-RESET send if communication with node is prohibited */
1434         if ((tipc_node_blocked(l_ptr->owner)) && (msg_typ != RESET_MSG))
1435                 return;
1436
1437         /* Create protocol message with "out-of-sequence" sequence number */
1438         msg_set_type(msg, msg_typ);
1439         msg_set_net_plane(msg, l_ptr->net_plane);
1440         msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1441         msg_set_last_bcast(msg, tipc_bclink_get_last_sent());
1442
1443         if (msg_typ == STATE_MSG) {
1444                 u32 next_sent = mod(l_ptr->next_out_no);
1445
1446                 if (!tipc_link_is_up(l_ptr))
1447                         return;
1448                 if (l_ptr->next_out)
1449                         next_sent = buf_seqno(l_ptr->next_out);
1450                 msg_set_next_sent(msg, next_sent);
1451                 if (l_ptr->oldest_deferred_in) {
1452                         u32 rec = buf_seqno(l_ptr->oldest_deferred_in);
1453                         gap = mod(rec - mod(l_ptr->next_in_no));
1454                 }
1455                 msg_set_seq_gap(msg, gap);
1456                 if (gap)
1457                         l_ptr->stats.sent_nacks++;
1458                 msg_set_link_tolerance(msg, tolerance);
1459                 msg_set_linkprio(msg, priority);
1460                 msg_set_max_pkt(msg, ack_mtu);
1461                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1462                 msg_set_probe(msg, probe_msg != 0);
1463                 if (probe_msg) {
1464                         u32 mtu = l_ptr->max_pkt;
1465
1466                         if ((mtu < l_ptr->max_pkt_target) &&
1467                             link_working_working(l_ptr) &&
1468                             l_ptr->fsm_msg_cnt) {
1469                                 msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
1470                                 if (l_ptr->max_pkt_probes == 10) {
1471                                         l_ptr->max_pkt_target = (msg_size - 4);
1472                                         l_ptr->max_pkt_probes = 0;
1473                                         msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
1474                                 }
1475                                 l_ptr->max_pkt_probes++;
1476                         }
1477
1478                         l_ptr->stats.sent_probes++;
1479                 }
1480                 l_ptr->stats.sent_states++;
1481         } else {                /* RESET_MSG or ACTIVATE_MSG */
1482                 msg_set_ack(msg, mod(l_ptr->reset_checkpoint - 1));
1483                 msg_set_seq_gap(msg, 0);
1484                 msg_set_next_sent(msg, 1);
1485                 msg_set_probe(msg, 0);
1486                 msg_set_link_tolerance(msg, l_ptr->tolerance);
1487                 msg_set_linkprio(msg, l_ptr->priority);
1488                 msg_set_max_pkt(msg, l_ptr->max_pkt_target);
1489         }
1490
1491         r_flag = (l_ptr->owner->working_links > tipc_link_is_up(l_ptr));
1492         msg_set_redundant_link(msg, r_flag);
1493         msg_set_linkprio(msg, l_ptr->priority);
1494         msg_set_size(msg, msg_size);
1495
1496         msg_set_seqno(msg, mod(l_ptr->next_out_no + (0xffff/2)));
1497
1498         buf = tipc_buf_acquire(msg_size);
1499         if (!buf)
1500                 return;
1501
1502         skb_copy_to_linear_data(buf, msg, sizeof(l_ptr->proto_msg));
1503         buf->priority = TC_PRIO_CONTROL;
1504
1505         tipc_bearer_send(l_ptr->bearer_id, buf, &l_ptr->media_addr);
1506         l_ptr->unacked_window = 0;
1507         kfree_skb(buf);
1508 }
1509
1510 /*
1511  * Receive protocol message :
1512  * Note that network plane id propagates through the network, and may
1513  * change at any time. The node with lowest address rules
1514  */
1515 static void tipc_link_proto_rcv(struct tipc_link *l_ptr, struct sk_buff *buf)
1516 {
1517         u32 rec_gap = 0;
1518         u32 max_pkt_info;
1519         u32 max_pkt_ack;
1520         u32 msg_tol;
1521         struct tipc_msg *msg = buf_msg(buf);
1522
1523         /* Discard protocol message during link changeover */
1524         if (l_ptr->exp_msg_count)
1525                 goto exit;
1526
1527         if (l_ptr->net_plane != msg_net_plane(msg))
1528                 if (tipc_own_addr > msg_prevnode(msg))
1529                         l_ptr->net_plane = msg_net_plane(msg);
1530
1531         switch (msg_type(msg)) {
1532
1533         case RESET_MSG:
1534                 if (!link_working_unknown(l_ptr) &&
1535                     (l_ptr->peer_session != INVALID_SESSION)) {
1536                         if (less_eq(msg_session(msg), l_ptr->peer_session))
1537                                 break; /* duplicate or old reset: ignore */
1538                 }
1539
1540                 if (!msg_redundant_link(msg) && (link_working_working(l_ptr) ||
1541                                 link_working_unknown(l_ptr))) {
1542                         /*
1543                          * peer has lost contact -- don't allow peer's links
1544                          * to reactivate before we recognize loss & clean up
1545                          */
1546                         l_ptr->owner->action_flags |= TIPC_WAIT_OWN_LINKS_DOWN;
1547                 }
1548
1549                 link_state_event(l_ptr, RESET_MSG);
1550
1551                 /* fall thru' */
1552         case ACTIVATE_MSG:
1553                 /* Update link settings according other endpoint's values */
1554                 strcpy((strrchr(l_ptr->name, ':') + 1), (char *)msg_data(msg));
1555
1556                 msg_tol = msg_link_tolerance(msg);
1557                 if (msg_tol > l_ptr->tolerance)
1558                         link_set_supervision_props(l_ptr, msg_tol);
1559
1560                 if (msg_linkprio(msg) > l_ptr->priority)
1561                         l_ptr->priority = msg_linkprio(msg);
1562
1563                 max_pkt_info = msg_max_pkt(msg);
1564                 if (max_pkt_info) {
1565                         if (max_pkt_info < l_ptr->max_pkt_target)
1566                                 l_ptr->max_pkt_target = max_pkt_info;
1567                         if (l_ptr->max_pkt > l_ptr->max_pkt_target)
1568                                 l_ptr->max_pkt = l_ptr->max_pkt_target;
1569                 } else {
1570                         l_ptr->max_pkt = l_ptr->max_pkt_target;
1571                 }
1572
1573                 /* Synchronize broadcast link info, if not done previously */
1574                 if (!tipc_node_is_up(l_ptr->owner)) {
1575                         l_ptr->owner->bclink.last_sent =
1576                                 l_ptr->owner->bclink.last_in =
1577                                 msg_last_bcast(msg);
1578                         l_ptr->owner->bclink.oos_state = 0;
1579                 }
1580
1581                 l_ptr->peer_session = msg_session(msg);
1582                 l_ptr->peer_bearer_id = msg_bearer_id(msg);
1583
1584                 if (msg_type(msg) == ACTIVATE_MSG)
1585                         link_state_event(l_ptr, ACTIVATE_MSG);
1586                 break;
1587         case STATE_MSG:
1588
1589                 msg_tol = msg_link_tolerance(msg);
1590                 if (msg_tol)
1591                         link_set_supervision_props(l_ptr, msg_tol);
1592
1593                 if (msg_linkprio(msg) &&
1594                     (msg_linkprio(msg) != l_ptr->priority)) {
1595                         pr_warn("%s<%s>, priority change %u->%u\n",
1596                                 link_rst_msg, l_ptr->name, l_ptr->priority,
1597                                 msg_linkprio(msg));
1598                         l_ptr->priority = msg_linkprio(msg);
1599                         tipc_link_reset(l_ptr); /* Enforce change to take effect */
1600                         break;
1601                 }
1602
1603                 /* Record reception; force mismatch at next timeout: */
1604                 l_ptr->checkpoint--;
1605
1606                 link_state_event(l_ptr, TRAFFIC_MSG_EVT);
1607                 l_ptr->stats.recv_states++;
1608                 if (link_reset_unknown(l_ptr))
1609                         break;
1610
1611                 if (less_eq(mod(l_ptr->next_in_no), msg_next_sent(msg))) {
1612                         rec_gap = mod(msg_next_sent(msg) -
1613                                       mod(l_ptr->next_in_no));
1614                 }
1615
1616                 max_pkt_ack = msg_max_pkt(msg);
1617                 if (max_pkt_ack > l_ptr->max_pkt) {
1618                         l_ptr->max_pkt = max_pkt_ack;
1619                         l_ptr->max_pkt_probes = 0;
1620                 }
1621
1622                 max_pkt_ack = 0;
1623                 if (msg_probe(msg)) {
1624                         l_ptr->stats.recv_probes++;
1625                         if (msg_size(msg) > sizeof(l_ptr->proto_msg))
1626                                 max_pkt_ack = msg_size(msg);
1627                 }
1628
1629                 /* Protocol message before retransmits, reduce loss risk */
1630                 if (l_ptr->owner->bclink.recv_permitted)
1631                         tipc_bclink_update_link_state(l_ptr->owner,
1632                                                       msg_last_bcast(msg));
1633
1634                 if (rec_gap || (msg_probe(msg))) {
1635                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, rec_gap, 0,
1636                                              0, max_pkt_ack);
1637                 }
1638                 if (msg_seq_gap(msg)) {
1639                         l_ptr->stats.recv_nacks++;
1640                         tipc_link_retransmit(l_ptr, l_ptr->first_out,
1641                                              msg_seq_gap(msg));
1642                 }
1643                 break;
1644         }
1645 exit:
1646         kfree_skb(buf);
1647 }
1648
1649
1650 /* tipc_link_tunnel_xmit(): Tunnel one packet via a link belonging to
1651  * a different bearer. Owner node is locked.
1652  */
1653 static void tipc_link_tunnel_xmit(struct tipc_link *l_ptr,
1654                                   struct tipc_msg *tunnel_hdr,
1655                                   struct tipc_msg *msg,
1656                                   u32 selector)
1657 {
1658         struct tipc_link *tunnel;
1659         struct sk_buff *buf;
1660         u32 length = msg_size(msg);
1661
1662         tunnel = l_ptr->owner->active_links[selector & 1];
1663         if (!tipc_link_is_up(tunnel)) {
1664                 pr_warn("%stunnel link no longer available\n", link_co_err);
1665                 return;
1666         }
1667         msg_set_size(tunnel_hdr, length + INT_H_SIZE);
1668         buf = tipc_buf_acquire(length + INT_H_SIZE);
1669         if (!buf) {
1670                 pr_warn("%sunable to send tunnel msg\n", link_co_err);
1671                 return;
1672         }
1673         skb_copy_to_linear_data(buf, tunnel_hdr, INT_H_SIZE);
1674         skb_copy_to_linear_data_offset(buf, INT_H_SIZE, msg, length);
1675         __tipc_link_xmit(tunnel, buf);
1676 }
1677
1678
1679 /* tipc_link_failover_send_queue(): A link has gone down, but a second
1680  * link is still active. We can do failover. Tunnel the failing link's
1681  * whole send queue via the remaining link. This way, we don't lose
1682  * any packets, and sequence order is preserved for subsequent traffic
1683  * sent over the remaining link. Owner node is locked.
1684  */
1685 void tipc_link_failover_send_queue(struct tipc_link *l_ptr)
1686 {
1687         u32 msgcount = l_ptr->out_queue_size;
1688         struct sk_buff *crs = l_ptr->first_out;
1689         struct tipc_link *tunnel = l_ptr->owner->active_links[0];
1690         struct tipc_msg tunnel_hdr;
1691         int split_bundles;
1692
1693         if (!tunnel)
1694                 return;
1695
1696         tipc_msg_init(&tunnel_hdr, CHANGEOVER_PROTOCOL,
1697                  ORIGINAL_MSG, INT_H_SIZE, l_ptr->addr);
1698         msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
1699         msg_set_msgcnt(&tunnel_hdr, msgcount);
1700
1701         if (!l_ptr->first_out) {
1702                 struct sk_buff *buf;
1703
1704                 buf = tipc_buf_acquire(INT_H_SIZE);
1705                 if (buf) {
1706                         skb_copy_to_linear_data(buf, &tunnel_hdr, INT_H_SIZE);
1707                         msg_set_size(&tunnel_hdr, INT_H_SIZE);
1708                         __tipc_link_xmit(tunnel, buf);
1709                 } else {
1710                         pr_warn("%sunable to send changeover msg\n",
1711                                 link_co_err);
1712                 }
1713                 return;
1714         }
1715
1716         split_bundles = (l_ptr->owner->active_links[0] !=
1717                          l_ptr->owner->active_links[1]);
1718
1719         while (crs) {
1720                 struct tipc_msg *msg = buf_msg(crs);
1721
1722                 if ((msg_user(msg) == MSG_BUNDLER) && split_bundles) {
1723                         struct tipc_msg *m = msg_get_wrapped(msg);
1724                         unchar *pos = (unchar *)m;
1725
1726                         msgcount = msg_msgcnt(msg);
1727                         while (msgcount--) {
1728                                 msg_set_seqno(m, msg_seqno(msg));
1729                                 tipc_link_tunnel_xmit(l_ptr, &tunnel_hdr, m,
1730                                                       msg_link_selector(m));
1731                                 pos += align(msg_size(m));
1732                                 m = (struct tipc_msg *)pos;
1733                         }
1734                 } else {
1735                         tipc_link_tunnel_xmit(l_ptr, &tunnel_hdr, msg,
1736                                               msg_link_selector(msg));
1737                 }
1738                 crs = crs->next;
1739         }
1740 }
1741
1742 /* tipc_link_dup_queue_xmit(): A second link has become active. Tunnel a
1743  * duplicate of the first link's send queue via the new link. This way, we
1744  * are guaranteed that currently queued packets from a socket are delivered
1745  * before future traffic from the same socket, even if this is using the
1746  * new link. The last arriving copy of each duplicate packet is dropped at
1747  * the receiving end by the regular protocol check, so packet cardinality
1748  * and sequence order is preserved per sender/receiver socket pair.
1749  * Owner node is locked.
1750  */
1751 void tipc_link_dup_queue_xmit(struct tipc_link *l_ptr,
1752                               struct tipc_link *tunnel)
1753 {
1754         struct sk_buff *iter;
1755         struct tipc_msg tunnel_hdr;
1756
1757         tipc_msg_init(&tunnel_hdr, CHANGEOVER_PROTOCOL,
1758                  DUPLICATE_MSG, INT_H_SIZE, l_ptr->addr);
1759         msg_set_msgcnt(&tunnel_hdr, l_ptr->out_queue_size);
1760         msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
1761         iter = l_ptr->first_out;
1762         while (iter) {
1763                 struct sk_buff *outbuf;
1764                 struct tipc_msg *msg = buf_msg(iter);
1765                 u32 length = msg_size(msg);
1766
1767                 if (msg_user(msg) == MSG_BUNDLER)
1768                         msg_set_type(msg, CLOSED_MSG);
1769                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));   /* Update */
1770                 msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1771                 msg_set_size(&tunnel_hdr, length + INT_H_SIZE);
1772                 outbuf = tipc_buf_acquire(length + INT_H_SIZE);
1773                 if (outbuf == NULL) {
1774                         pr_warn("%sunable to send duplicate msg\n",
1775                                 link_co_err);
1776                         return;
1777                 }
1778                 skb_copy_to_linear_data(outbuf, &tunnel_hdr, INT_H_SIZE);
1779                 skb_copy_to_linear_data_offset(outbuf, INT_H_SIZE, iter->data,
1780                                                length);
1781                 __tipc_link_xmit(tunnel, outbuf);
1782                 if (!tipc_link_is_up(l_ptr))
1783                         return;
1784                 iter = iter->next;
1785         }
1786 }
1787
1788 /**
1789  * buf_extract - extracts embedded TIPC message from another message
1790  * @skb: encapsulating message buffer
1791  * @from_pos: offset to extract from
1792  *
1793  * Returns a new message buffer containing an embedded message.  The
1794  * encapsulating message itself is left unchanged.
1795  */
1796 static struct sk_buff *buf_extract(struct sk_buff *skb, u32 from_pos)
1797 {
1798         struct tipc_msg *msg = (struct tipc_msg *)(skb->data + from_pos);
1799         u32 size = msg_size(msg);
1800         struct sk_buff *eb;
1801
1802         eb = tipc_buf_acquire(size);
1803         if (eb)
1804                 skb_copy_to_linear_data(eb, msg, size);
1805         return eb;
1806 }
1807
1808
1809
1810 /* tipc_link_dup_rcv(): Receive a tunnelled DUPLICATE_MSG packet.
1811  * Owner node is locked.
1812  */
1813 static void tipc_link_dup_rcv(struct tipc_link *l_ptr,
1814                               struct sk_buff *t_buf)
1815 {
1816         struct sk_buff *buf;
1817
1818         if (!tipc_link_is_up(l_ptr))
1819                 return;
1820
1821         buf = buf_extract(t_buf, INT_H_SIZE);
1822         if (buf == NULL) {
1823                 pr_warn("%sfailed to extract inner dup pkt\n", link_co_err);
1824                 return;
1825         }
1826
1827         /* Add buffer to deferred queue, if applicable: */
1828         link_handle_out_of_seq_msg(l_ptr, buf);
1829 }
1830
1831 /*  tipc_link_failover_rcv(): Receive a tunnelled ORIGINAL_MSG packet
1832  *  Owner node is locked.
1833  */
1834 static struct sk_buff *tipc_link_failover_rcv(struct tipc_link *l_ptr,
1835                                               struct sk_buff *t_buf)
1836 {
1837         struct tipc_msg *t_msg = buf_msg(t_buf);
1838         struct sk_buff *buf = NULL;
1839         struct tipc_msg *msg;
1840
1841         if (tipc_link_is_up(l_ptr))
1842                 tipc_link_reset(l_ptr);
1843
1844         /* First failover packet? */
1845         if (l_ptr->exp_msg_count == START_CHANGEOVER)
1846                 l_ptr->exp_msg_count = msg_msgcnt(t_msg);
1847
1848         /* Should there be an inner packet? */
1849         if (l_ptr->exp_msg_count) {
1850                 l_ptr->exp_msg_count--;
1851                 buf = buf_extract(t_buf, INT_H_SIZE);
1852                 if (buf == NULL) {
1853                         pr_warn("%sno inner failover pkt\n", link_co_err);
1854                         goto exit;
1855                 }
1856                 msg = buf_msg(buf);
1857
1858                 if (less(msg_seqno(msg), l_ptr->reset_checkpoint)) {
1859                         kfree_skb(buf);
1860                         buf = NULL;
1861                         goto exit;
1862                 }
1863                 if (msg_user(msg) == MSG_FRAGMENTER) {
1864                         l_ptr->stats.recv_fragments++;
1865                         tipc_buf_append(&l_ptr->reasm_buf, &buf);
1866                 }
1867         }
1868 exit:
1869         if ((l_ptr->exp_msg_count == 0) && (l_ptr->flags & LINK_STOPPED)) {
1870                 tipc_node_detach_link(l_ptr->owner, l_ptr);
1871                 kfree(l_ptr);
1872         }
1873         return buf;
1874 }
1875
1876 /*  tipc_link_tunnel_rcv(): Receive a tunnelled packet, sent
1877  *  via other link as result of a failover (ORIGINAL_MSG) or
1878  *  a new active link (DUPLICATE_MSG). Failover packets are
1879  *  returned to the active link for delivery upwards.
1880  *  Owner node is locked.
1881  */
1882 static int tipc_link_tunnel_rcv(struct tipc_node *n_ptr,
1883                                 struct sk_buff **buf)
1884 {
1885         struct sk_buff *t_buf = *buf;
1886         struct tipc_link *l_ptr;
1887         struct tipc_msg *t_msg = buf_msg(t_buf);
1888         u32 bearer_id = msg_bearer_id(t_msg);
1889
1890         *buf = NULL;
1891
1892         if (bearer_id >= MAX_BEARERS)
1893                 goto exit;
1894
1895         l_ptr = n_ptr->links[bearer_id];
1896         if (!l_ptr)
1897                 goto exit;
1898
1899         if (msg_type(t_msg) == DUPLICATE_MSG)
1900                 tipc_link_dup_rcv(l_ptr, t_buf);
1901         else if (msg_type(t_msg) == ORIGINAL_MSG)
1902                 *buf = tipc_link_failover_rcv(l_ptr, t_buf);
1903         else
1904                 pr_warn("%sunknown tunnel pkt received\n", link_co_err);
1905 exit:
1906         kfree_skb(t_buf);
1907         return *buf != NULL;
1908 }
1909
1910 /*
1911  *  Bundler functionality:
1912  */
1913 void tipc_link_bundle_rcv(struct sk_buff *buf)
1914 {
1915         u32 msgcount = msg_msgcnt(buf_msg(buf));
1916         u32 pos = INT_H_SIZE;
1917         struct sk_buff *obuf;
1918         struct tipc_msg *omsg;
1919
1920         while (msgcount--) {
1921                 obuf = buf_extract(buf, pos);
1922                 if (obuf == NULL) {
1923                         pr_warn("Link unable to unbundle message(s)\n");
1924                         break;
1925                 }
1926                 omsg = buf_msg(obuf);
1927                 pos += align(msg_size(omsg));
1928                 if (msg_isdata(omsg)) {
1929                         if (unlikely(msg_type(omsg) == TIPC_MCAST_MSG))
1930                                 tipc_sk_mcast_rcv(obuf);
1931                         else
1932                                 tipc_sk_rcv(obuf);
1933                 } else if (msg_user(omsg) == CONN_MANAGER) {
1934                         tipc_sk_rcv(obuf);
1935                 } else if (msg_user(omsg) == NAME_DISTRIBUTOR) {
1936                         tipc_named_rcv(obuf);
1937                 } else {
1938                         pr_warn("Illegal bundled msg: %u\n", msg_user(omsg));
1939                         kfree_skb(obuf);
1940                 }
1941         }
1942         kfree_skb(buf);
1943 }
1944
1945 static void link_set_supervision_props(struct tipc_link *l_ptr, u32 tolerance)
1946 {
1947         if ((tolerance < TIPC_MIN_LINK_TOL) || (tolerance > TIPC_MAX_LINK_TOL))
1948                 return;
1949
1950         l_ptr->tolerance = tolerance;
1951         l_ptr->continuity_interval =
1952                 ((tolerance / 4) > 500) ? 500 : tolerance / 4;
1953         l_ptr->abort_limit = tolerance / (l_ptr->continuity_interval / 4);
1954 }
1955
1956 void tipc_link_set_queue_limits(struct tipc_link *l_ptr, u32 window)
1957 {
1958         /* Data messages from this node, inclusive FIRST_FRAGM */
1959         l_ptr->queue_limit[TIPC_LOW_IMPORTANCE] = window;
1960         l_ptr->queue_limit[TIPC_MEDIUM_IMPORTANCE] = (window / 3) * 4;
1961         l_ptr->queue_limit[TIPC_HIGH_IMPORTANCE] = (window / 3) * 5;
1962         l_ptr->queue_limit[TIPC_CRITICAL_IMPORTANCE] = (window / 3) * 6;
1963         /* Transiting data messages,inclusive FIRST_FRAGM */
1964         l_ptr->queue_limit[TIPC_LOW_IMPORTANCE + 4] = 300;
1965         l_ptr->queue_limit[TIPC_MEDIUM_IMPORTANCE + 4] = 600;
1966         l_ptr->queue_limit[TIPC_HIGH_IMPORTANCE + 4] = 900;
1967         l_ptr->queue_limit[TIPC_CRITICAL_IMPORTANCE + 4] = 1200;
1968         l_ptr->queue_limit[CONN_MANAGER] = 1200;
1969         l_ptr->queue_limit[CHANGEOVER_PROTOCOL] = 2500;
1970         l_ptr->queue_limit[NAME_DISTRIBUTOR] = 3000;
1971         /* FRAGMENT and LAST_FRAGMENT packets */
1972         l_ptr->queue_limit[MSG_FRAGMENTER] = 4000;
1973 }
1974
1975 /* tipc_link_find_owner - locate owner node of link by link's name
1976  * @name: pointer to link name string
1977  * @bearer_id: pointer to index in 'node->links' array where the link was found.
1978  *
1979  * Returns pointer to node owning the link, or 0 if no matching link is found.
1980  */
1981 static struct tipc_node *tipc_link_find_owner(const char *link_name,
1982                                               unsigned int *bearer_id)
1983 {
1984         struct tipc_link *l_ptr;
1985         struct tipc_node *n_ptr;
1986         struct tipc_node *found_node = 0;
1987         int i;
1988
1989         *bearer_id = 0;
1990         rcu_read_lock();
1991         list_for_each_entry_rcu(n_ptr, &tipc_node_list, list) {
1992                 tipc_node_lock(n_ptr);
1993                 for (i = 0; i < MAX_BEARERS; i++) {
1994                         l_ptr = n_ptr->links[i];
1995                         if (l_ptr && !strcmp(l_ptr->name, link_name)) {
1996                                 *bearer_id = i;
1997                                 found_node = n_ptr;
1998                                 break;
1999                         }
2000                 }
2001                 tipc_node_unlock(n_ptr);
2002                 if (found_node)
2003                         break;
2004         }
2005         rcu_read_unlock();
2006
2007         return found_node;
2008 }
2009
2010 /**
2011  * link_value_is_valid -- validate proposed link tolerance/priority/window
2012  *
2013  * @cmd: value type (TIPC_CMD_SET_LINK_*)
2014  * @new_value: the new value
2015  *
2016  * Returns 1 if value is within range, 0 if not.
2017  */
2018 static int link_value_is_valid(u16 cmd, u32 new_value)
2019 {
2020         switch (cmd) {
2021         case TIPC_CMD_SET_LINK_TOL:
2022                 return (new_value >= TIPC_MIN_LINK_TOL) &&
2023                         (new_value <= TIPC_MAX_LINK_TOL);
2024         case TIPC_CMD_SET_LINK_PRI:
2025                 return (new_value <= TIPC_MAX_LINK_PRI);
2026         case TIPC_CMD_SET_LINK_WINDOW:
2027                 return (new_value >= TIPC_MIN_LINK_WIN) &&
2028                         (new_value <= TIPC_MAX_LINK_WIN);
2029         }
2030         return 0;
2031 }
2032
2033 /**
2034  * link_cmd_set_value - change priority/tolerance/window for link/bearer/media
2035  * @name: ptr to link, bearer, or media name
2036  * @new_value: new value of link, bearer, or media setting
2037  * @cmd: which link, bearer, or media attribute to set (TIPC_CMD_SET_LINK_*)
2038  *
2039  * Caller must hold RTNL lock to ensure link/bearer/media is not deleted.
2040  *
2041  * Returns 0 if value updated and negative value on error.
2042  */
2043 static int link_cmd_set_value(const char *name, u32 new_value, u16 cmd)
2044 {
2045         struct tipc_node *node;
2046         struct tipc_link *l_ptr;
2047         struct tipc_bearer *b_ptr;
2048         struct tipc_media *m_ptr;
2049         int bearer_id;
2050         int res = 0;
2051
2052         node = tipc_link_find_owner(name, &bearer_id);
2053         if (node) {
2054                 tipc_node_lock(node);
2055                 l_ptr = node->links[bearer_id];
2056
2057                 if (l_ptr) {
2058                         switch (cmd) {
2059                         case TIPC_CMD_SET_LINK_TOL:
2060                                 link_set_supervision_props(l_ptr, new_value);
2061                                 tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, 0,
2062                                                      new_value, 0, 0);
2063                                 break;
2064                         case TIPC_CMD_SET_LINK_PRI:
2065                                 l_ptr->priority = new_value;
2066                                 tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, 0,
2067                                                      0, new_value, 0);
2068                                 break;
2069                         case TIPC_CMD_SET_LINK_WINDOW:
2070                                 tipc_link_set_queue_limits(l_ptr, new_value);
2071                                 break;
2072                         default:
2073                                 res = -EINVAL;
2074                                 break;
2075                         }
2076                 }
2077                 tipc_node_unlock(node);
2078                 return res;
2079         }
2080
2081         b_ptr = tipc_bearer_find(name);
2082         if (b_ptr) {
2083                 switch (cmd) {
2084                 case TIPC_CMD_SET_LINK_TOL:
2085                         b_ptr->tolerance = new_value;
2086                         break;
2087                 case TIPC_CMD_SET_LINK_PRI:
2088                         b_ptr->priority = new_value;
2089                         break;
2090                 case TIPC_CMD_SET_LINK_WINDOW:
2091                         b_ptr->window = new_value;
2092                         break;
2093                 default:
2094                         res = -EINVAL;
2095                         break;
2096                 }
2097                 return res;
2098         }
2099
2100         m_ptr = tipc_media_find(name);
2101         if (!m_ptr)
2102                 return -ENODEV;
2103         switch (cmd) {
2104         case TIPC_CMD_SET_LINK_TOL:
2105                 m_ptr->tolerance = new_value;
2106                 break;
2107         case TIPC_CMD_SET_LINK_PRI:
2108                 m_ptr->priority = new_value;
2109                 break;
2110         case TIPC_CMD_SET_LINK_WINDOW:
2111                 m_ptr->window = new_value;
2112                 break;
2113         default:
2114                 res = -EINVAL;
2115                 break;
2116         }
2117         return res;
2118 }
2119
2120 struct sk_buff *tipc_link_cmd_config(const void *req_tlv_area, int req_tlv_space,
2121                                      u16 cmd)
2122 {
2123         struct tipc_link_config *args;
2124         u32 new_value;
2125         int res;
2126
2127         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_CONFIG))
2128                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2129
2130         args = (struct tipc_link_config *)TLV_DATA(req_tlv_area);
2131         new_value = ntohl(args->value);
2132
2133         if (!link_value_is_valid(cmd, new_value))
2134                 return tipc_cfg_reply_error_string(
2135                         "cannot change, value invalid");
2136
2137         if (!strcmp(args->name, tipc_bclink_name)) {
2138                 if ((cmd == TIPC_CMD_SET_LINK_WINDOW) &&
2139                     (tipc_bclink_set_queue_limits(new_value) == 0))
2140                         return tipc_cfg_reply_none();
2141                 return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
2142                                                    " (cannot change setting on broadcast link)");
2143         }
2144
2145         res = link_cmd_set_value(args->name, new_value, cmd);
2146         if (res)
2147                 return tipc_cfg_reply_error_string("cannot change link setting");
2148
2149         return tipc_cfg_reply_none();
2150 }
2151
2152 /**
2153  * link_reset_statistics - reset link statistics
2154  * @l_ptr: pointer to link
2155  */
2156 static void link_reset_statistics(struct tipc_link *l_ptr)
2157 {
2158         memset(&l_ptr->stats, 0, sizeof(l_ptr->stats));
2159         l_ptr->stats.sent_info = l_ptr->next_out_no;
2160         l_ptr->stats.recv_info = l_ptr->next_in_no;
2161 }
2162
2163 struct sk_buff *tipc_link_cmd_reset_stats(const void *req_tlv_area, int req_tlv_space)
2164 {
2165         char *link_name;
2166         struct tipc_link *l_ptr;
2167         struct tipc_node *node;
2168         unsigned int bearer_id;
2169
2170         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_NAME))
2171                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2172
2173         link_name = (char *)TLV_DATA(req_tlv_area);
2174         if (!strcmp(link_name, tipc_bclink_name)) {
2175                 if (tipc_bclink_reset_stats())
2176                         return tipc_cfg_reply_error_string("link not found");
2177                 return tipc_cfg_reply_none();
2178         }
2179         node = tipc_link_find_owner(link_name, &bearer_id);
2180         if (!node)
2181                 return tipc_cfg_reply_error_string("link not found");
2182
2183         tipc_node_lock(node);
2184         l_ptr = node->links[bearer_id];
2185         if (!l_ptr) {
2186                 tipc_node_unlock(node);
2187                 return tipc_cfg_reply_error_string("link not found");
2188         }
2189         link_reset_statistics(l_ptr);
2190         tipc_node_unlock(node);
2191         return tipc_cfg_reply_none();
2192 }
2193
2194 /**
2195  * percent - convert count to a percentage of total (rounding up or down)
2196  */
2197 static u32 percent(u32 count, u32 total)
2198 {
2199         return (count * 100 + (total / 2)) / total;
2200 }
2201
2202 /**
2203  * tipc_link_stats - print link statistics
2204  * @name: link name
2205  * @buf: print buffer area
2206  * @buf_size: size of print buffer area
2207  *
2208  * Returns length of print buffer data string (or 0 if error)
2209  */
2210 static int tipc_link_stats(const char *name, char *buf, const u32 buf_size)
2211 {
2212         struct tipc_link *l;
2213         struct tipc_stats *s;
2214         struct tipc_node *node;
2215         char *status;
2216         u32 profile_total = 0;
2217         unsigned int bearer_id;
2218         int ret;
2219
2220         if (!strcmp(name, tipc_bclink_name))
2221                 return tipc_bclink_stats(buf, buf_size);
2222
2223         node = tipc_link_find_owner(name, &bearer_id);
2224         if (!node)
2225                 return 0;
2226
2227         tipc_node_lock(node);
2228
2229         l = node->links[bearer_id];
2230         if (!l) {
2231                 tipc_node_unlock(node);
2232                 return 0;
2233         }
2234
2235         s = &l->stats;
2236
2237         if (tipc_link_is_active(l))
2238                 status = "ACTIVE";
2239         else if (tipc_link_is_up(l))
2240                 status = "STANDBY";
2241         else
2242                 status = "DEFUNCT";
2243
2244         ret = tipc_snprintf(buf, buf_size, "Link <%s>\n"
2245                             "  %s  MTU:%u  Priority:%u  Tolerance:%u ms"
2246                             "  Window:%u packets\n",
2247                             l->name, status, l->max_pkt, l->priority,
2248                             l->tolerance, l->queue_limit[0]);
2249
2250         ret += tipc_snprintf(buf + ret, buf_size - ret,
2251                              "  RX packets:%u fragments:%u/%u bundles:%u/%u\n",
2252                              l->next_in_no - s->recv_info, s->recv_fragments,
2253                              s->recv_fragmented, s->recv_bundles,
2254                              s->recv_bundled);
2255
2256         ret += tipc_snprintf(buf + ret, buf_size - ret,
2257                              "  TX packets:%u fragments:%u/%u bundles:%u/%u\n",
2258                              l->next_out_no - s->sent_info, s->sent_fragments,
2259                              s->sent_fragmented, s->sent_bundles,
2260                              s->sent_bundled);
2261
2262         profile_total = s->msg_length_counts;
2263         if (!profile_total)
2264                 profile_total = 1;
2265
2266         ret += tipc_snprintf(buf + ret, buf_size - ret,
2267                              "  TX profile sample:%u packets  average:%u octets\n"
2268                              "  0-64:%u%% -256:%u%% -1024:%u%% -4096:%u%% "
2269                              "-16384:%u%% -32768:%u%% -66000:%u%%\n",
2270                              s->msg_length_counts,
2271                              s->msg_lengths_total / profile_total,
2272                              percent(s->msg_length_profile[0], profile_total),
2273                              percent(s->msg_length_profile[1], profile_total),
2274                              percent(s->msg_length_profile[2], profile_total),
2275                              percent(s->msg_length_profile[3], profile_total),
2276                              percent(s->msg_length_profile[4], profile_total),
2277                              percent(s->msg_length_profile[5], profile_total),
2278                              percent(s->msg_length_profile[6], profile_total));
2279
2280         ret += tipc_snprintf(buf + ret, buf_size - ret,
2281                              "  RX states:%u probes:%u naks:%u defs:%u"
2282                              " dups:%u\n", s->recv_states, s->recv_probes,
2283                              s->recv_nacks, s->deferred_recv, s->duplicates);
2284
2285         ret += tipc_snprintf(buf + ret, buf_size - ret,
2286                              "  TX states:%u probes:%u naks:%u acks:%u"
2287                              " dups:%u\n", s->sent_states, s->sent_probes,
2288                              s->sent_nacks, s->sent_acks, s->retransmitted);
2289
2290         ret += tipc_snprintf(buf + ret, buf_size - ret,
2291                              "  Congestion link:%u  Send queue"
2292                              " max:%u avg:%u\n", s->link_congs,
2293                              s->max_queue_sz, s->queue_sz_counts ?
2294                              (s->accu_queue_sz / s->queue_sz_counts) : 0);
2295
2296         tipc_node_unlock(node);
2297         return ret;
2298 }
2299
2300 struct sk_buff *tipc_link_cmd_show_stats(const void *req_tlv_area, int req_tlv_space)
2301 {
2302         struct sk_buff *buf;
2303         struct tlv_desc *rep_tlv;
2304         int str_len;
2305         int pb_len;
2306         char *pb;
2307
2308         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_NAME))
2309                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2310
2311         buf = tipc_cfg_reply_alloc(TLV_SPACE(ULTRA_STRING_MAX_LEN));
2312         if (!buf)
2313                 return NULL;
2314
2315         rep_tlv = (struct tlv_desc *)buf->data;
2316         pb = TLV_DATA(rep_tlv);
2317         pb_len = ULTRA_STRING_MAX_LEN;
2318         str_len = tipc_link_stats((char *)TLV_DATA(req_tlv_area),
2319                                   pb, pb_len);
2320         if (!str_len) {
2321                 kfree_skb(buf);
2322                 return tipc_cfg_reply_error_string("link not found");
2323         }
2324         str_len += 1;   /* for "\0" */
2325         skb_put(buf, TLV_SPACE(str_len));
2326         TLV_SET(rep_tlv, TIPC_TLV_ULTRA_STRING, NULL, str_len);
2327
2328         return buf;
2329 }
2330
2331 /**
2332  * tipc_link_get_max_pkt - get maximum packet size to use when sending to destination
2333  * @dest: network address of destination node
2334  * @selector: used to select from set of active links
2335  *
2336  * If no active link can be found, uses default maximum packet size.
2337  */
2338 u32 tipc_link_get_max_pkt(u32 dest, u32 selector)
2339 {
2340         struct tipc_node *n_ptr;
2341         struct tipc_link *l_ptr;
2342         u32 res = MAX_PKT_DEFAULT;
2343
2344         if (dest == tipc_own_addr)
2345                 return MAX_MSG_SIZE;
2346
2347         n_ptr = tipc_node_find(dest);
2348         if (n_ptr) {
2349                 tipc_node_lock(n_ptr);
2350                 l_ptr = n_ptr->active_links[selector & 1];
2351                 if (l_ptr)
2352                         res = l_ptr->max_pkt;
2353                 tipc_node_unlock(n_ptr);
2354         }
2355         return res;
2356 }
2357
2358 static void link_print(struct tipc_link *l_ptr, const char *str)
2359 {
2360         struct tipc_bearer *b_ptr;
2361
2362         rcu_read_lock();
2363         b_ptr = rcu_dereference_rtnl(bearer_list[l_ptr->bearer_id]);
2364         if (b_ptr)
2365                 pr_info("%s Link %x<%s>:", str, l_ptr->addr, b_ptr->name);
2366         rcu_read_unlock();
2367
2368         if (link_working_unknown(l_ptr))
2369                 pr_cont(":WU\n");
2370         else if (link_reset_reset(l_ptr))
2371                 pr_cont(":RR\n");
2372         else if (link_reset_unknown(l_ptr))
2373                 pr_cont(":RU\n");
2374         else if (link_working_working(l_ptr))
2375                 pr_cont(":WW\n");
2376         else
2377                 pr_cont("\n");
2378 }