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