net/tipc/link.c

   1 /*
   2  * net/tipc/link.c: TIPC link code
   3  *
   4  * Copyright (c) 1996-2007, 2012-2015, 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 "subscr.h"
  39 #include "link.h"
  40 #include "bcast.h"
  41 #include "socket.h"
  42 #include "name_distr.h"
  43 #include "discover.h"
  44 #include "netlink.h"
  45
  46 #include <linux/pkt_sched.h>
  47
  48 /*
  49  * Error message prefixes
  50  */
  51 static const char *link_co_err = "Link changeover error, ";
  52 static const char *link_rst_msg = "Resetting link ";
  53 static const char *link_unk_evt = "Unknown link event ";
  54
  55 static const struct nla_policy tipc_nl_link_policy[TIPC_NLA_LINK_MAX + 1] = {
  56         [TIPC_NLA_LINK_UNSPEC]          = { .type = NLA_UNSPEC },
  57         [TIPC_NLA_LINK_NAME] = {
  58                 .type = NLA_STRING,
  59                 .len = TIPC_MAX_LINK_NAME
  60         },
  61         [TIPC_NLA_LINK_MTU]             = { .type = NLA_U32 },
  62         [TIPC_NLA_LINK_BROADCAST]       = { .type = NLA_FLAG },
  63         [TIPC_NLA_LINK_UP]              = { .type = NLA_FLAG },
  64         [TIPC_NLA_LINK_ACTIVE]          = { .type = NLA_FLAG },
  65         [TIPC_NLA_LINK_PROP]            = { .type = NLA_NESTED },
  66         [TIPC_NLA_LINK_STATS]           = { .type = NLA_NESTED },
  67         [TIPC_NLA_LINK_RX]              = { .type = NLA_U32 },
  68         [TIPC_NLA_LINK_TX]              = { .type = NLA_U32 }
  69 };
  70
  71 /* Properties valid for media, bearar and link */
  72 static const struct nla_policy tipc_nl_prop_policy[TIPC_NLA_PROP_MAX + 1] = {
  73         [TIPC_NLA_PROP_UNSPEC]          = { .type = NLA_UNSPEC },
  74         [TIPC_NLA_PROP_PRIO]            = { .type = NLA_U32 },
  75         [TIPC_NLA_PROP_TOL]             = { .type = NLA_U32 },
  76         [TIPC_NLA_PROP_WIN]             = { .type = NLA_U32 }
  77 };
  78
  79 /*
  80  * Out-of-range value for link session numbers
  81  */
  82 #define INVALID_SESSION 0x10000
  83
  84 /*
  85  * Link state events:
  86  */
  87 #define  STARTING_EVT    856384768      /* link processing trigger */
  88 #define  TRAFFIC_MSG_EVT 560815u        /* rx'd ??? */
  89 #define  TIMEOUT_EVT     560817u        /* link timer expired */
  90
  91 /*
  92  * The following two 'message types' is really just implementation
  93  * data conveniently stored in the message header.
  94  * They must not be considered part of the protocol
  95  */
  96 #define OPEN_MSG   0
  97 #define CLOSED_MSG 1
  98
  99 /*
 100  * State value stored in 'exp_msg_count'
 101  */
 102 #define START_CHANGEOVER 100000u
 103
 104 static void link_handle_out_of_seq_msg(struct tipc_link *link,
 105                                        struct sk_buff *skb);
 106 static void tipc_link_proto_rcv(struct tipc_link *link,
 107                                 struct sk_buff *skb);
 108 static void link_set_supervision_props(struct tipc_link *l_ptr, u32 tol);
 109 static void link_state_event(struct tipc_link *l_ptr, u32 event);
 110 static void link_reset_statistics(struct tipc_link *l_ptr);
 111 static void link_print(struct tipc_link *l_ptr, const char *str);
 112 static void tipc_link_sync_xmit(struct tipc_link *l);
 113 static void tipc_link_sync_rcv(struct tipc_node *n, struct sk_buff *buf);
 114 static void tipc_link_input(struct tipc_link *l, struct sk_buff *skb);
 115 static bool tipc_data_input(struct tipc_link *l, struct sk_buff *skb);
 116 static bool tipc_link_failover_rcv(struct tipc_node *node,
 117                                    struct sk_buff **skb);
 118 /*
 119  *  Simple link routines
 120  */
 121 static unsigned int align(unsigned int i)
 122 {
 123         return (i + 3) & ~3u;
 124 }
 125
 126 static void tipc_link_release(struct kref *kref)
 127 {
 128         kfree(container_of(kref, struct tipc_link, ref));
 129 }
 130
 131 static void tipc_link_get(struct tipc_link *l_ptr)
 132 {
 133         kref_get(&l_ptr->ref);
 134 }
 135
 136 static void tipc_link_put(struct tipc_link *l_ptr)
 137 {
 138         kref_put(&l_ptr->ref, tipc_link_release);
 139 }
 140
 141 static struct tipc_link *tipc_parallel_link(struct tipc_link *l)
 142 {
 143         if (l->owner->active_links[0] != l)
 144                 return l->owner->active_links[0];
 145         return l->owner->active_links[1];
 146 }
 147
 148 static void link_init_max_pkt(struct tipc_link *l_ptr)
 149 {
 150         struct tipc_node *node = l_ptr->owner;
 151         struct tipc_net *tn = net_generic(node->net, tipc_net_id);
 152         struct tipc_bearer *b_ptr;
 153         u32 max_pkt;
 154
 155         rcu_read_lock();
 156         b_ptr = rcu_dereference_rtnl(tn->bearer_list[l_ptr->bearer_id]);
 157         if (!b_ptr) {
 158                 rcu_read_unlock();
 159                 return;
 160         }
 161         max_pkt = (b_ptr->mtu & ~3);
 162         rcu_read_unlock();
 163
 164         if (max_pkt > MAX_MSG_SIZE)
 165                 max_pkt = MAX_MSG_SIZE;
 166
 167         l_ptr->max_pkt_target = max_pkt;
 168         if (l_ptr->max_pkt_target < MAX_PKT_DEFAULT)
 169                 l_ptr->max_pkt = l_ptr->max_pkt_target;
 170         else
 171                 l_ptr->max_pkt = MAX_PKT_DEFAULT;
 172
 173         l_ptr->max_pkt_probes = 0;
 174 }
 175
 176 /*
 177  *  Simple non-static link routines (i.e. referenced outside this file)
 178  */
 179 int tipc_link_is_up(struct tipc_link *l_ptr)
 180 {
 181         if (!l_ptr)
 182                 return 0;
 183         return link_working_working(l_ptr) || link_working_unknown(l_ptr);
 184 }
 185
 186 int tipc_link_is_active(struct tipc_link *l_ptr)
 187 {
 188         return  (l_ptr->owner->active_links[0] == l_ptr) ||
 189                 (l_ptr->owner->active_links[1] == l_ptr);
 190 }
 191
 192 /**
 193  * link_timeout - handle expiration of link timer
 194  * @l_ptr: pointer to link
 195  */
 196 static void link_timeout(unsigned long data)
 197 {
 198         struct tipc_link *l_ptr = (struct tipc_link *)data;
 199         struct sk_buff *skb;
 200
 201         tipc_node_lock(l_ptr->owner);
 202
 203         /* update counters used in statistical profiling of send traffic */
 204         l_ptr->stats.accu_queue_sz += skb_queue_len(&l_ptr->transmq);
 205         l_ptr->stats.queue_sz_counts++;
 206
 207         skb = skb_peek(&l_ptr->transmq);
 208         if (skb) {
 209                 struct tipc_msg *msg = buf_msg(skb);
 210                 u32 length = msg_size(msg);
 211
 212                 if ((msg_user(msg) == MSG_FRAGMENTER) &&
 213                     (msg_type(msg) == FIRST_FRAGMENT)) {
 214                         length = msg_size(msg_get_wrapped(msg));
 215                 }
 216                 if (length) {
 217                         l_ptr->stats.msg_lengths_total += length;
 218                         l_ptr->stats.msg_length_counts++;
 219                         if (length <= 64)
 220                                 l_ptr->stats.msg_length_profile[0]++;
 221                         else if (length <= 256)
 222                                 l_ptr->stats.msg_length_profile[1]++;
 223                         else if (length <= 1024)
 224                                 l_ptr->stats.msg_length_profile[2]++;
 225                         else if (length <= 4096)
 226                                 l_ptr->stats.msg_length_profile[3]++;
 227                         else if (length <= 16384)
 228                                 l_ptr->stats.msg_length_profile[4]++;
 229                         else if (length <= 32768)
 230                                 l_ptr->stats.msg_length_profile[5]++;
 231                         else
 232                                 l_ptr->stats.msg_length_profile[6]++;
 233                 }
 234         }
 235
 236         /* do all other link processing performed on a periodic basis */
 237         link_state_event(l_ptr, TIMEOUT_EVT);
 238
 239         if (skb_queue_len(&l_ptr->backlogq))
 240                 tipc_link_push_packets(l_ptr);
 241
 242         tipc_node_unlock(l_ptr->owner);
 243         tipc_link_put(l_ptr);
 244 }
 245
 246 static void link_set_timer(struct tipc_link *link, unsigned long time)
 247 {
 248         if (!mod_timer(&link->timer, jiffies + time))
 249                 tipc_link_get(link);
 250 }
 251
 252 /**
 253  * tipc_link_create - create a new link
 254  * @n_ptr: pointer to associated node
 255  * @b_ptr: pointer to associated bearer
 256  * @media_addr: media address to use when sending messages over link
 257  *
 258  * Returns pointer to link.
 259  */
 260 struct tipc_link *tipc_link_create(struct tipc_node *n_ptr,
 261                                    struct tipc_bearer *b_ptr,
 262                                    const struct tipc_media_addr *media_addr)
 263 {
 264         struct tipc_net *tn = net_generic(n_ptr->net, tipc_net_id);
 265         struct tipc_link *l_ptr;
 266         struct tipc_msg *msg;
 267         char *if_name;
 268         char addr_string[16];
 269         u32 peer = n_ptr->addr;
 270
 271         if (n_ptr->link_cnt >= MAX_BEARERS) {
 272                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 273                 pr_err("Attempt to establish %uth link to %s. Max %u allowed.\n",
 274                         n_ptr->link_cnt, addr_string, MAX_BEARERS);
 275                 return NULL;
 276         }
 277
 278         if (n_ptr->links[b_ptr->identity]) {
 279                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 280                 pr_err("Attempt to establish second link on <%s> to %s\n",
 281                        b_ptr->name, addr_string);
 282                 return NULL;
 283         }
 284
 285         l_ptr = kzalloc(sizeof(*l_ptr), GFP_ATOMIC);
 286         if (!l_ptr) {
 287                 pr_warn("Link creation failed, no memory\n");
 288                 return NULL;
 289         }
 290         kref_init(&l_ptr->ref);
 291         l_ptr->addr = peer;
 292         if_name = strchr(b_ptr->name, ':') + 1;
 293         sprintf(l_ptr->name, "%u.%u.%u:%s-%u.%u.%u:unknown",
 294                 tipc_zone(tn->own_addr), tipc_cluster(tn->own_addr),
 295                 tipc_node(tn->own_addr),
 296                 if_name,
 297                 tipc_zone(peer), tipc_cluster(peer), tipc_node(peer));
 298                 /* note: peer i/f name is updated by reset/activate message */
 299         memcpy(&l_ptr->media_addr, media_addr, sizeof(*media_addr));
 300         l_ptr->owner = n_ptr;
 301         l_ptr->checkpoint = 1;
 302         l_ptr->peer_session = INVALID_SESSION;
 303         l_ptr->bearer_id = b_ptr->identity;
 304         link_set_supervision_props(l_ptr, b_ptr->tolerance);
 305         l_ptr->state = RESET_UNKNOWN;
 306
 307         l_ptr->pmsg = (struct tipc_msg *)&l_ptr->proto_msg;
 308         msg = l_ptr->pmsg;
 309         tipc_msg_init(tn->own_addr, msg, LINK_PROTOCOL, RESET_MSG, INT_H_SIZE,
 310                       l_ptr->addr);
 311         msg_set_size(msg, sizeof(l_ptr->proto_msg));
 312         msg_set_session(msg, (tn->random & 0xffff));
 313         msg_set_bearer_id(msg, b_ptr->identity);
 314         strcpy((char *)msg_data(msg), if_name);
 315         l_ptr->net_plane = b_ptr->net_plane;
 316         link_init_max_pkt(l_ptr);
 317         l_ptr->priority = b_ptr->priority;
 318         tipc_link_set_queue_limits(l_ptr, b_ptr->window);
 319         l_ptr->next_out_no = 1;
 320         __skb_queue_head_init(&l_ptr->transmq);
 321         __skb_queue_head_init(&l_ptr->backlogq);
 322         __skb_queue_head_init(&l_ptr->deferdq);
 323         skb_queue_head_init(&l_ptr->wakeupq);
 324         skb_queue_head_init(&l_ptr->inputq);
 325         skb_queue_head_init(&l_ptr->namedq);
 326         link_reset_statistics(l_ptr);
 327         tipc_node_attach_link(n_ptr, l_ptr);
 328         setup_timer(&l_ptr->timer, link_timeout, (unsigned long)l_ptr);
 329         link_state_event(l_ptr, STARTING_EVT);
 330
 331         return l_ptr;
 332 }
 333
 334 /**
 335  * link_delete - Conditional deletion of link.
 336  *               If timer still running, real delete is done when it expires
 337  * @link: link to be deleted
 338  */
 339 void tipc_link_delete(struct tipc_link *link)
 340 {
 341         tipc_link_reset_fragments(link);
 342         tipc_node_detach_link(link->owner, link);
 343         tipc_link_put(link);
 344 }
 345
 346 void tipc_link_delete_list(struct net *net, unsigned int bearer_id,
 347                            bool shutting_down)
 348 {
 349         struct tipc_net *tn = net_generic(net, tipc_net_id);
 350         struct tipc_link *link;
 351         struct tipc_node *node;
 352         bool del_link;
 353
 354         rcu_read_lock();
 355         list_for_each_entry_rcu(node, &tn->node_list, list) {
 356                 tipc_node_lock(node);
 357                 link = node->links[bearer_id];
 358                 if (!link) {
 359                         tipc_node_unlock(node);
 360                         continue;
 361                 }
 362                 del_link = !tipc_link_is_up(link) && !link->exp_msg_count;
 363                 tipc_link_reset(link);
 364                 if (del_timer(&link->timer))
 365                         tipc_link_put(link);
 366                 link->flags |= LINK_STOPPED;
 367                 /* Delete link now, or when failover is finished: */
 368                 if (shutting_down || !tipc_node_is_up(node) || del_link)
 369                         tipc_link_delete(link);
 370                 tipc_node_unlock(node);
 371         }
 372         rcu_read_unlock();
 373 }
 374
 375 /**
 376  * link_schedule_user - schedule a message sender for wakeup after congestion
 377  * @link: congested link
 378  * @list: message that was attempted sent
 379  * Create pseudo msg to send back to user when congestion abates
 380  * Only consumes message if there is an error
 381  */
 382 static int link_schedule_user(struct tipc_link *link, struct sk_buff_head *list)
 383 {
 384         struct tipc_msg *msg = buf_msg(skb_peek(list));
 385         int imp = msg_importance(msg);
 386         u32 oport = msg_origport(msg);
 387         u32 addr = link_own_addr(link);
 388         struct sk_buff *skb;
 389
 390         /* This really cannot happen...  */
 391         if (unlikely(imp > TIPC_CRITICAL_IMPORTANCE)) {
 392                 pr_warn("%s<%s>, send queue full", link_rst_msg, link->name);
 393                 tipc_link_reset(link);
 394                 goto err;
 395         }
 396         /* Non-blocking sender: */
 397         if (TIPC_SKB_CB(skb_peek(list))->wakeup_pending)
 398                 return -ELINKCONG;
 399
 400         /* Create and schedule wakeup pseudo message */
 401         skb = tipc_msg_create(SOCK_WAKEUP, 0, INT_H_SIZE, 0,
 402                               addr, addr, oport, 0, 0);
 403         if (!skb)
 404                 goto err;
 405         TIPC_SKB_CB(skb)->chain_sz = skb_queue_len(list);
 406         TIPC_SKB_CB(skb)->chain_imp = imp;
 407         skb_queue_tail(&link->wakeupq, skb);
 408         link->stats.link_congs++;
 409         return -ELINKCONG;
 410 err:
 411         __skb_queue_purge(list);
 412         return -ENOBUFS;
 413 }
 414
 415 /**
 416  * link_prepare_wakeup - prepare users for wakeup after congestion
 417  * @link: congested link
 418  * Move a number of waiting users, as permitted by available space in
 419  * the send queue, from link wait queue to node wait queue for wakeup
 420  */
 421 void link_prepare_wakeup(struct tipc_link *l)
 422 {
 423         int pnd[TIPC_SYSTEM_IMPORTANCE + 1] = {0,};
 424         int imp, lim;
 425         struct sk_buff *skb, *tmp;
 426
 427         skb_queue_walk_safe(&l->wakeupq, skb, tmp) {
 428                 imp = TIPC_SKB_CB(skb)->chain_imp;
 429                 lim = l->window + l->backlog[imp].limit;
 430                 pnd[imp] += TIPC_SKB_CB(skb)->chain_sz;
 431                 if ((pnd[imp] + l->backlog[imp].len) >= lim)
 432                         break;
 433                 skb_unlink(skb, &l->wakeupq);
 434                 skb_queue_tail(&l->inputq, skb);
 435                 l->owner->inputq = &l->inputq;
 436                 l->owner->action_flags |= TIPC_MSG_EVT;
 437         }
 438 }
 439
 440 /**
 441  * tipc_link_reset_fragments - purge link's inbound message fragments queue
 442  * @l_ptr: pointer to link
 443  */
 444 void tipc_link_reset_fragments(struct tipc_link *l_ptr)
 445 {
 446         kfree_skb(l_ptr->reasm_buf);
 447         l_ptr->reasm_buf = NULL;
 448 }
 449
 450 static void tipc_link_purge_backlog(struct tipc_link *l)
 451 {
 452         __skb_queue_purge(&l->backlogq);
 453         l->backlog[TIPC_LOW_IMPORTANCE].len = 0;
 454         l->backlog[TIPC_MEDIUM_IMPORTANCE].len = 0;
 455         l->backlog[TIPC_HIGH_IMPORTANCE].len = 0;
 456         l->backlog[TIPC_CRITICAL_IMPORTANCE].len = 0;
 457         l->backlog[TIPC_SYSTEM_IMPORTANCE].len = 0;
 458 }
 459
 460 /**
 461  * tipc_link_purge_queues - purge all pkt queues associated with link
 462  * @l_ptr: pointer to link
 463  */
 464 void tipc_link_purge_queues(struct tipc_link *l_ptr)
 465 {
 466         __skb_queue_purge(&l_ptr->deferdq);
 467         __skb_queue_purge(&l_ptr->transmq);
 468         tipc_link_purge_backlog(l_ptr);
 469         tipc_link_reset_fragments(l_ptr);
 470 }
 471
 472 void tipc_link_reset(struct tipc_link *l_ptr)
 473 {
 474         u32 prev_state = l_ptr->state;
 475         u32 checkpoint = l_ptr->next_in_no;
 476         int was_active_link = tipc_link_is_active(l_ptr);
 477         struct tipc_node *owner = l_ptr->owner;
 478
 479         msg_set_session(l_ptr->pmsg, ((msg_session(l_ptr->pmsg) + 1) & 0xffff));
 480
 481         /* Link is down, accept any session */
 482         l_ptr->peer_session = INVALID_SESSION;
 483
 484         /* Prepare for max packet size negotiation */
 485         link_init_max_pkt(l_ptr);
 486
 487         l_ptr->state = RESET_UNKNOWN;
 488
 489         if ((prev_state == RESET_UNKNOWN) || (prev_state == RESET_RESET))
 490                 return;
 491
 492         tipc_node_link_down(l_ptr->owner, l_ptr);
 493         tipc_bearer_remove_dest(owner->net, l_ptr->bearer_id, l_ptr->addr);
 494
 495         if (was_active_link && tipc_node_active_links(l_ptr->owner)) {
 496                 l_ptr->reset_checkpoint = checkpoint;
 497                 l_ptr->exp_msg_count = START_CHANGEOVER;
 498         }
 499
 500         /* Clean up all queues, except inputq: */
 501         __skb_queue_purge(&l_ptr->transmq);
 502         __skb_queue_purge(&l_ptr->deferdq);
 503         if (!owner->inputq)
 504                 owner->inputq = &l_ptr->inputq;
 505         skb_queue_splice_init(&l_ptr->wakeupq, owner->inputq);
 506         if (!skb_queue_empty(owner->inputq))
 507                 owner->action_flags |= TIPC_MSG_EVT;
 508         tipc_link_purge_backlog(l_ptr);
 509         l_ptr->rcv_unacked = 0;
 510         l_ptr->checkpoint = 1;
 511         l_ptr->next_out_no = 1;
 512         l_ptr->fsm_msg_cnt = 0;
 513         l_ptr->stale_count = 0;
 514         link_reset_statistics(l_ptr);
 515 }
 516
 517 void tipc_link_reset_list(struct net *net, unsigned int bearer_id)
 518 {
 519         struct tipc_net *tn = net_generic(net, tipc_net_id);
 520         struct tipc_link *l_ptr;
 521         struct tipc_node *n_ptr;
 522
 523         rcu_read_lock();
 524         list_for_each_entry_rcu(n_ptr, &tn->node_list, list) {
 525                 tipc_node_lock(n_ptr);
 526                 l_ptr = n_ptr->links[bearer_id];
 527                 if (l_ptr)
 528                         tipc_link_reset(l_ptr);
 529                 tipc_node_unlock(n_ptr);
 530         }
 531         rcu_read_unlock();
 532 }
 533
 534 static void link_activate(struct tipc_link *link)
 535 {
 536         struct tipc_node *node = link->owner;
 537
 538         link->next_in_no = 1;
 539         link->stats.recv_info = 1;
 540         tipc_node_link_up(node, link);
 541         tipc_bearer_add_dest(node->net, link->bearer_id, link->addr);
 542 }
 543
 544 /**
 545  * link_state_event - link finite state machine
 546  * @l_ptr: pointer to link
 547  * @event: state machine event to process
 548  */
 549 static void link_state_event(struct tipc_link *l_ptr, unsigned int event)
 550 {
 551         struct tipc_link *other;
 552         unsigned long cont_intv = l_ptr->cont_intv;
 553
 554         if (l_ptr->flags & LINK_STOPPED)
 555                 return;
 556
 557         if (!(l_ptr->flags & LINK_STARTED) && (event != STARTING_EVT))
 558                 return;         /* Not yet. */
 559
 560         /* Check whether changeover is going on */
 561         if (l_ptr->exp_msg_count) {
 562                 if (event == TIMEOUT_EVT)
 563                         link_set_timer(l_ptr, cont_intv);
 564                 return;
 565         }
 566
 567         switch (l_ptr->state) {
 568         case WORKING_WORKING:
 569                 switch (event) {
 570                 case TRAFFIC_MSG_EVT:
 571                 case ACTIVATE_MSG:
 572                         break;
 573                 case TIMEOUT_EVT:
 574                         if (l_ptr->next_in_no != l_ptr->checkpoint) {
 575                                 l_ptr->checkpoint = l_ptr->next_in_no;
 576                                 if (tipc_bclink_acks_missing(l_ptr->owner)) {
 577                                         tipc_link_proto_xmit(l_ptr, STATE_MSG,
 578                                                              0, 0, 0, 0, 0);
 579                                         l_ptr->fsm_msg_cnt++;
 580                                 } else if (l_ptr->max_pkt < l_ptr->max_pkt_target) {
 581                                         tipc_link_proto_xmit(l_ptr, STATE_MSG,
 582                                                              1, 0, 0, 0, 0);
 583                                         l_ptr->fsm_msg_cnt++;
 584                                 }
 585                                 link_set_timer(l_ptr, cont_intv);
 586                                 break;
 587                         }
 588                         l_ptr->state = WORKING_UNKNOWN;
 589                         l_ptr->fsm_msg_cnt = 0;
 590                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
 591                         l_ptr->fsm_msg_cnt++;
 592                         link_set_timer(l_ptr, cont_intv / 4);
 593                         break;
 594                 case RESET_MSG:
 595                         pr_debug("%s<%s>, requested by peer\n",
 596                                  link_rst_msg, l_ptr->name);
 597                         tipc_link_reset(l_ptr);
 598                         l_ptr->state = RESET_RESET;
 599                         l_ptr->fsm_msg_cnt = 0;
 600                         tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
 601                                              0, 0, 0, 0, 0);
 602                         l_ptr->fsm_msg_cnt++;
 603                         link_set_timer(l_ptr, cont_intv);
 604                         break;
 605                 default:
 606                         pr_debug("%s%u in WW state\n", link_unk_evt, event);
 607                 }
 608                 break;
 609         case WORKING_UNKNOWN:
 610                 switch (event) {
 611                 case TRAFFIC_MSG_EVT:
 612                 case ACTIVATE_MSG:
 613                         l_ptr->state = WORKING_WORKING;
 614                         l_ptr->fsm_msg_cnt = 0;
 615                         link_set_timer(l_ptr, cont_intv);
 616                         break;
 617                 case RESET_MSG:
 618                         pr_debug("%s<%s>, requested by peer while probing\n",
 619                                  link_rst_msg, l_ptr->name);
 620                         tipc_link_reset(l_ptr);
 621                         l_ptr->state = RESET_RESET;
 622                         l_ptr->fsm_msg_cnt = 0;
 623                         tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
 624                                              0, 0, 0, 0, 0);
 625                         l_ptr->fsm_msg_cnt++;
 626                         link_set_timer(l_ptr, cont_intv);
 627                         break;
 628                 case TIMEOUT_EVT:
 629                         if (l_ptr->next_in_no != l_ptr->checkpoint) {
 630                                 l_ptr->state = WORKING_WORKING;
 631                                 l_ptr->fsm_msg_cnt = 0;
 632                                 l_ptr->checkpoint = l_ptr->next_in_no;
 633                                 if (tipc_bclink_acks_missing(l_ptr->owner)) {
 634                                         tipc_link_proto_xmit(l_ptr, STATE_MSG,
 635                                                              0, 0, 0, 0, 0);
 636                                         l_ptr->fsm_msg_cnt++;
 637                                 }
 638                                 link_set_timer(l_ptr, cont_intv);
 639                         } else if (l_ptr->fsm_msg_cnt < l_ptr->abort_limit) {
 640                                 tipc_link_proto_xmit(l_ptr, STATE_MSG,
 641                                                      1, 0, 0, 0, 0);
 642                                 l_ptr->fsm_msg_cnt++;
 643                                 link_set_timer(l_ptr, cont_intv / 4);
 644                         } else {        /* Link has failed */
 645                                 pr_debug("%s<%s>, peer not responding\n",
 646                                          link_rst_msg, l_ptr->name);
 647                                 tipc_link_reset(l_ptr);
 648                                 l_ptr->state = RESET_UNKNOWN;
 649                                 l_ptr->fsm_msg_cnt = 0;
 650                                 tipc_link_proto_xmit(l_ptr, RESET_MSG,
 651                                                      0, 0, 0, 0, 0);
 652                                 l_ptr->fsm_msg_cnt++;
 653                                 link_set_timer(l_ptr, cont_intv);
 654                         }
 655                         break;
 656                 default:
 657                         pr_err("%s%u in WU state\n", link_unk_evt, event);
 658                 }
 659                 break;
 660         case RESET_UNKNOWN:
 661                 switch (event) {
 662                 case TRAFFIC_MSG_EVT:
 663                         break;
 664                 case ACTIVATE_MSG:
 665                         other = l_ptr->owner->active_links[0];
 666                         if (other && link_working_unknown(other))
 667                                 break;
 668                         l_ptr->state = WORKING_WORKING;
 669                         l_ptr->fsm_msg_cnt = 0;
 670                         link_activate(l_ptr);
 671                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
 672                         l_ptr->fsm_msg_cnt++;
 673                         if (l_ptr->owner->working_links == 1)
 674                                 tipc_link_sync_xmit(l_ptr);
 675                         link_set_timer(l_ptr, cont_intv);
 676                         break;
 677                 case RESET_MSG:
 678                         l_ptr->state = RESET_RESET;
 679                         l_ptr->fsm_msg_cnt = 0;
 680                         tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
 681                                              1, 0, 0, 0, 0);
 682                         l_ptr->fsm_msg_cnt++;
 683                         link_set_timer(l_ptr, cont_intv);
 684                         break;
 685                 case STARTING_EVT:
 686                         l_ptr->flags |= LINK_STARTED;
 687                         l_ptr->fsm_msg_cnt++;
 688                         link_set_timer(l_ptr, cont_intv);
 689                         break;
 690                 case TIMEOUT_EVT:
 691                         tipc_link_proto_xmit(l_ptr, RESET_MSG, 0, 0, 0, 0, 0);
 692                         l_ptr->fsm_msg_cnt++;
 693                         link_set_timer(l_ptr, cont_intv);
 694                         break;
 695                 default:
 696                         pr_err("%s%u in RU state\n", link_unk_evt, event);
 697                 }
 698                 break;
 699         case RESET_RESET:
 700                 switch (event) {
 701                 case TRAFFIC_MSG_EVT:
 702                 case ACTIVATE_MSG:
 703                         other = l_ptr->owner->active_links[0];
 704                         if (other && link_working_unknown(other))
 705                                 break;
 706                         l_ptr->state = WORKING_WORKING;
 707                         l_ptr->fsm_msg_cnt = 0;
 708                         link_activate(l_ptr);
 709                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
 710                         l_ptr->fsm_msg_cnt++;
 711                         if (l_ptr->owner->working_links == 1)
 712                                 tipc_link_sync_xmit(l_ptr);
 713                         link_set_timer(l_ptr, cont_intv);
 714                         break;
 715                 case RESET_MSG:
 716                         break;
 717                 case TIMEOUT_EVT:
 718                         tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
 719                                              0, 0, 0, 0, 0);
 720                         l_ptr->fsm_msg_cnt++;
 721                         link_set_timer(l_ptr, cont_intv);
 722                         break;
 723                 default:
 724                         pr_err("%s%u in RR state\n", link_unk_evt, event);
 725                 }
 726                 break;
 727         default:
 728                 pr_err("Unknown link state %u/%u\n", l_ptr->state, event);
 729         }
 730 }
 731
 732 /**
 733  * __tipc_link_xmit(): same as tipc_link_xmit, but destlink is known & locked
 734  * @link: link to use
 735  * @list: chain of buffers containing message
 736  *
 737  * Consumes the buffer chain, except when returning -ELINKCONG,
 738  * since the caller then may want to make more send attempts.
 739  * Returns 0 if success, or errno: -ELINKCONG, -EMSGSIZE or -ENOBUFS
 740  * Messages at TIPC_SYSTEM_IMPORTANCE are always accepted
 741  */
 742 int __tipc_link_xmit(struct net *net, struct tipc_link *link,
 743                      struct sk_buff_head *list)
 744 {
 745         struct tipc_msg *msg = buf_msg(skb_peek(list));
 746         unsigned int maxwin = link->window;
 747         unsigned int imp = msg_importance(msg);
 748         uint mtu = link->max_pkt;
 749         uint ack = mod(link->next_in_no - 1);
 750         uint seqno = link->next_out_no;
 751         uint bc_last_in = link->owner->bclink.last_in;
 752         struct tipc_media_addr *addr = &link->media_addr;
 753         struct sk_buff_head *transmq = &link->transmq;
 754         struct sk_buff_head *backlogq = &link->backlogq;
 755         struct sk_buff *skb, *tmp;
 756
 757         /* Match backlog limit against msg importance: */
 758         if (unlikely(link->backlog[imp].len >= link->backlog[imp].limit))
 759                 return link_schedule_user(link, list);
 760
 761         if (unlikely(msg_size(msg) > mtu)) {
 762                 __skb_queue_purge(list);
 763                 return -EMSGSIZE;
 764         }
 765         /* Prepare each packet for sending, and add to relevant queue: */
 766         skb_queue_walk_safe(list, skb, tmp) {
 767                 __skb_unlink(skb, list);
 768                 msg = buf_msg(skb);
 769                 msg_set_seqno(msg, seqno);
 770                 msg_set_ack(msg, ack);
 771                 msg_set_bcast_ack(msg, bc_last_in);
 772
 773                 if (likely(skb_queue_len(transmq) < maxwin)) {
 774                         __skb_queue_tail(transmq, skb);
 775                         tipc_bearer_send(net, link->bearer_id, skb, addr);
 776                         link->rcv_unacked = 0;
 777                         seqno++;
 778                         continue;
 779                 }
 780                 if (tipc_msg_bundle(skb_peek_tail(backlogq), skb, mtu)) {
 781                         link->stats.sent_bundled++;
 782                         continue;
 783                 }
 784                 if (tipc_msg_make_bundle(&skb, mtu, link->addr)) {
 785                         link->stats.sent_bundled++;
 786                         link->stats.sent_bundles++;
 787                         imp = msg_importance(buf_msg(skb));
 788                 }
 789                 __skb_queue_tail(backlogq, skb);
 790                 link->backlog[imp].len++;
 791                 seqno++;
 792         }
 793         link->next_out_no = seqno;
 794         return 0;
 795 }
 796
 797 static void skb2list(struct sk_buff *skb, struct sk_buff_head *list)
 798 {
 799         skb_queue_head_init(list);
 800         __skb_queue_tail(list, skb);
 801 }
 802
 803 static int __tipc_link_xmit_skb(struct tipc_link *link, struct sk_buff *skb)
 804 {
 805         struct sk_buff_head head;
 806
 807         skb2list(skb, &head);
 808         return __tipc_link_xmit(link->owner->net, link, &head);
 809 }
 810
 811 /* tipc_link_xmit_skb(): send single buffer to destination
 812  * Buffers sent via this functon are generally TIPC_SYSTEM_IMPORTANCE
 813  * messages, which will not be rejected
 814  * The only exception is datagram messages rerouted after secondary
 815  * lookup, which are rare and safe to dispose of anyway.
 816  * TODO: Return real return value, and let callers use
 817  * tipc_wait_for_sendpkt() where applicable
 818  */
 819 int tipc_link_xmit_skb(struct net *net, struct sk_buff *skb, u32 dnode,
 820                        u32 selector)
 821 {
 822         struct sk_buff_head head;
 823         int rc;
 824
 825         skb2list(skb, &head);
 826         rc = tipc_link_xmit(net, &head, dnode, selector);
 827         if (rc == -ELINKCONG)
 828                 kfree_skb(skb);
 829         return 0;
 830 }
 831
 832 /**
 833  * tipc_link_xmit() is the general link level function for message sending
 834  * @net: the applicable net namespace
 835  * @list: chain of buffers containing message
 836  * @dsz: amount of user data to be sent
 837  * @dnode: address of destination node
 838  * @selector: a number used for deterministic link selection
 839  * Consumes the buffer chain, except when returning -ELINKCONG
 840  * Returns 0 if success, otherwise errno: -ELINKCONG,-EHOSTUNREACH,-EMSGSIZE
 841  */
 842 int tipc_link_xmit(struct net *net, struct sk_buff_head *list, u32 dnode,
 843                    u32 selector)
 844 {
 845         struct tipc_link *link = NULL;
 846         struct tipc_node *node;
 847         int rc = -EHOSTUNREACH;
 848
 849         node = tipc_node_find(net, dnode);
 850         if (node) {
 851                 tipc_node_lock(node);
 852                 link = node->active_links[selector & 1];
 853                 if (link)
 854                         rc = __tipc_link_xmit(net, link, list);
 855                 tipc_node_unlock(node);
 856                 tipc_node_put(node);
 857         }
 858         if (link)
 859                 return rc;
 860
 861         if (likely(in_own_node(net, dnode))) {
 862                 tipc_sk_rcv(net, list);
 863                 return 0;
 864         }
 865
 866         __skb_queue_purge(list);
 867         return rc;
 868 }
 869
 870 /*
 871  * tipc_link_sync_xmit - synchronize broadcast link endpoints.
 872  *
 873  * Give a newly added peer node the sequence number where it should
 874  * start receiving and acking broadcast packets.
 875  *
 876  * Called with node locked
 877  */
 878 static void tipc_link_sync_xmit(struct tipc_link *link)
 879 {
 880         struct sk_buff *skb;
 881         struct tipc_msg *msg;
 882
 883         skb = tipc_buf_acquire(INT_H_SIZE);
 884         if (!skb)
 885                 return;
 886
 887         msg = buf_msg(skb);
 888         tipc_msg_init(link_own_addr(link), msg, BCAST_PROTOCOL, STATE_MSG,
 889                       INT_H_SIZE, link->addr);
 890         msg_set_last_bcast(msg, link->owner->bclink.acked);
 891         __tipc_link_xmit_skb(link, skb);
 892 }
 893
 894 /*
 895  * tipc_link_sync_rcv - synchronize broadcast link endpoints.
 896  * Receive the sequence number where we should start receiving and
 897  * acking broadcast packets from a newly added peer node, and open
 898  * up for reception of such packets.
 899  *
 900  * Called with node locked
 901  */
 902 static void tipc_link_sync_rcv(struct tipc_node *n, struct sk_buff *buf)
 903 {
 904         struct tipc_msg *msg = buf_msg(buf);
 905
 906         n->bclink.last_sent = n->bclink.last_in = msg_last_bcast(msg);
 907         n->bclink.recv_permitted = true;
 908         kfree_skb(buf);
 909 }
 910
 911 /*
 912  * tipc_link_push_packets - push unsent packets to bearer
 913  *
 914  * Push out the unsent messages of a link where congestion
 915  * has abated. Node is locked.
 916  *
 917  * Called with node locked
 918  */
 919 void tipc_link_push_packets(struct tipc_link *link)
 920 {
 921         struct sk_buff *skb;
 922         struct tipc_msg *msg;
 923         unsigned int ack = mod(link->next_in_no - 1);
 924
 925         while (skb_queue_len(&link->transmq) < link->window) {
 926                 skb = __skb_dequeue(&link->backlogq);
 927                 if (!skb)
 928                         break;
 929                 msg = buf_msg(skb);
 930                 link->backlog[msg_importance(msg)].len--;
 931                 msg_set_ack(msg, ack);
 932                 msg_set_bcast_ack(msg, link->owner->bclink.last_in);
 933                 link->rcv_unacked = 0;
 934                 __skb_queue_tail(&link->transmq, skb);
 935                 tipc_bearer_send(link->owner->net, link->bearer_id,
 936                                  skb, &link->media_addr);
 937         }
 938 }
 939
 940 void tipc_link_reset_all(struct tipc_node *node)
 941 {
 942         char addr_string[16];
 943         u32 i;
 944
 945         tipc_node_lock(node);
 946
 947         pr_warn("Resetting all links to %s\n",
 948                 tipc_addr_string_fill(addr_string, node->addr));
 949
 950         for (i = 0; i < MAX_BEARERS; i++) {
 951                 if (node->links[i]) {
 952                         link_print(node->links[i], "Resetting link\n");
 953                         tipc_link_reset(node->links[i]);
 954                 }
 955         }
 956
 957         tipc_node_unlock(node);
 958 }
 959
 960 static void link_retransmit_failure(struct tipc_link *l_ptr,
 961                                     struct sk_buff *buf)
 962 {
 963         struct tipc_msg *msg = buf_msg(buf);
 964         struct net *net = l_ptr->owner->net;
 965
 966         pr_warn("Retransmission failure on link <%s>\n", l_ptr->name);
 967
 968         if (l_ptr->addr) {
 969                 /* Handle failure on standard link */
 970                 link_print(l_ptr, "Resetting link\n");
 971                 tipc_link_reset(l_ptr);
 972
 973         } else {
 974                 /* Handle failure on broadcast link */
 975                 struct tipc_node *n_ptr;
 976                 char addr_string[16];
 977
 978                 pr_info("Msg seq number: %u,  ", msg_seqno(msg));
 979                 pr_cont("Outstanding acks: %lu\n",
 980                         (unsigned long) TIPC_SKB_CB(buf)->handle);
 981
 982                 n_ptr = tipc_bclink_retransmit_to(net);
 983
 984                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 985                 pr_info("Broadcast link info for %s\n", addr_string);
 986                 pr_info("Reception permitted: %d,  Acked: %u\n",
 987                         n_ptr->bclink.recv_permitted,
 988                         n_ptr->bclink.acked);
 989                 pr_info("Last in: %u,  Oos state: %u,  Last sent: %u\n",
 990                         n_ptr->bclink.last_in,
 991                         n_ptr->bclink.oos_state,
 992                         n_ptr->bclink.last_sent);
 993
 994                 n_ptr->action_flags |= TIPC_BCAST_RESET;
 995                 l_ptr->stale_count = 0;
 996         }
 997 }
 998
 999 void tipc_link_retransmit(struct tipc_link *l_ptr, struct sk_buff *skb,
1000                           u32 retransmits)
1001 {
1002         struct tipc_msg *msg;
1003
1004         if (!skb)
1005                 return;
1006
1007         msg = buf_msg(skb);
1008
1009         /* Detect repeated retransmit failures */
1010         if (l_ptr->last_retransmitted == msg_seqno(msg)) {
1011                 if (++l_ptr->stale_count > 100) {
1012                         link_retransmit_failure(l_ptr, skb);
1013                         return;
1014                 }
1015         } else {
1016                 l_ptr->last_retransmitted = msg_seqno(msg);
1017                 l_ptr->stale_count = 1;
1018         }
1019
1020         skb_queue_walk_from(&l_ptr->transmq, skb) {
1021                 if (!retransmits)
1022                         break;
1023                 msg = buf_msg(skb);
1024                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1025                 msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1026                 tipc_bearer_send(l_ptr->owner->net, l_ptr->bearer_id, skb,
1027                                  &l_ptr->media_addr);
1028                 retransmits--;
1029                 l_ptr->stats.retransmitted++;
1030         }
1031 }
1032
1033 /* link_synch(): check if all packets arrived before the synch
1034  *               point have been consumed
1035  * Returns true if the parallel links are synched, otherwise false
1036  */
1037 static bool link_synch(struct tipc_link *l)
1038 {
1039         unsigned int post_synch;
1040         struct tipc_link *pl;
1041
1042         pl  = tipc_parallel_link(l);
1043         if (pl == l)
1044                 goto synched;
1045
1046         /* Was last pre-synch packet added to input queue ? */
1047         if (less_eq(pl->next_in_no, l->synch_point))
1048                 return false;
1049
1050         /* Is it still in the input queue ? */
1051         post_synch = mod(pl->next_in_no - l->synch_point) - 1;
1052         if (skb_queue_len(&pl->inputq) > post_synch)
1053                 return false;
1054 synched:
1055         l->flags &= ~LINK_SYNCHING;
1056         return true;
1057 }
1058
1059 static void link_retrieve_defq(struct tipc_link *link,
1060                                struct sk_buff_head *list)
1061 {
1062         u32 seq_no;
1063
1064         if (skb_queue_empty(&link->deferdq))
1065                 return;
1066
1067         seq_no = buf_seqno(skb_peek(&link->deferdq));
1068         if (seq_no == mod(link->next_in_no))
1069                 skb_queue_splice_tail_init(&link->deferdq, list);
1070 }
1071
1072 /**
1073  * tipc_rcv - process TIPC packets/messages arriving from off-node
1074  * @net: the applicable net namespace
1075  * @skb: TIPC packet
1076  * @b_ptr: pointer to bearer message arrived on
1077  *
1078  * Invoked with no locks held.  Bearer pointer must point to a valid bearer
1079  * structure (i.e. cannot be NULL), but bearer can be inactive.
1080  */
1081 void tipc_rcv(struct net *net, struct sk_buff *skb, struct tipc_bearer *b_ptr)
1082 {
1083         struct tipc_net *tn = net_generic(net, tipc_net_id);
1084         struct sk_buff_head head;
1085         struct tipc_node *n_ptr;
1086         struct tipc_link *l_ptr;
1087         struct sk_buff *skb1, *tmp;
1088         struct tipc_msg *msg;
1089         u32 seq_no;
1090         u32 ackd;
1091         u32 released;
1092
1093         skb2list(skb, &head);
1094
1095         while ((skb = __skb_dequeue(&head))) {
1096                 /* Ensure message is well-formed */
1097                 if (unlikely(!tipc_msg_validate(skb)))
1098                         goto discard;
1099
1100                 /* Handle arrival of a non-unicast link message */
1101                 msg = buf_msg(skb);
1102                 if (unlikely(msg_non_seq(msg))) {
1103                         if (msg_user(msg) ==  LINK_CONFIG)
1104                                 tipc_disc_rcv(net, skb, b_ptr);
1105                         else
1106                                 tipc_bclink_rcv(net, skb);
1107                         continue;
1108                 }
1109
1110                 /* Discard unicast link messages destined for another node */
1111                 if (unlikely(!msg_short(msg) &&
1112                              (msg_destnode(msg) != tn->own_addr)))
1113                         goto discard;
1114
1115                 /* Locate neighboring node that sent message */
1116                 n_ptr = tipc_node_find(net, msg_prevnode(msg));
1117                 if (unlikely(!n_ptr))
1118                         goto discard;
1119
1120                 tipc_node_lock(n_ptr);
1121                 /* Locate unicast link endpoint that should handle message */
1122                 l_ptr = n_ptr->links[b_ptr->identity];
1123                 if (unlikely(!l_ptr))
1124                         goto unlock;
1125
1126                 /* Verify that communication with node is currently allowed */
1127                 if ((n_ptr->action_flags & TIPC_WAIT_PEER_LINKS_DOWN) &&
1128                     msg_user(msg) == LINK_PROTOCOL &&
1129                     (msg_type(msg) == RESET_MSG ||
1130                     msg_type(msg) == ACTIVATE_MSG) &&
1131                     !msg_redundant_link(msg))
1132                         n_ptr->action_flags &= ~TIPC_WAIT_PEER_LINKS_DOWN;
1133
1134                 if (tipc_node_blocked(n_ptr))
1135                         goto unlock;
1136
1137                 /* Validate message sequence number info */
1138                 seq_no = msg_seqno(msg);
1139                 ackd = msg_ack(msg);
1140
1141                 /* Release acked messages */
1142                 if (unlikely(n_ptr->bclink.acked != msg_bcast_ack(msg)))
1143                         tipc_bclink_acknowledge(n_ptr, msg_bcast_ack(msg));
1144
1145                 released = 0;
1146                 skb_queue_walk_safe(&l_ptr->transmq, skb1, tmp) {
1147                         if (more(buf_seqno(skb1), ackd))
1148                                 break;
1149                          __skb_unlink(skb1, &l_ptr->transmq);
1150                          kfree_skb(skb1);
1151                          released = 1;
1152                 }
1153
1154                 /* Try sending any messages link endpoint has pending */
1155                 if (unlikely(skb_queue_len(&l_ptr->backlogq)))
1156                         tipc_link_push_packets(l_ptr);
1157
1158                 if (released && !skb_queue_empty(&l_ptr->wakeupq))
1159                         link_prepare_wakeup(l_ptr);
1160
1161                 /* Process the incoming packet */
1162                 if (unlikely(!link_working_working(l_ptr))) {
1163                         if (msg_user(msg) == LINK_PROTOCOL) {
1164                                 tipc_link_proto_rcv(l_ptr, skb);
1165                                 link_retrieve_defq(l_ptr, &head);
1166                                 skb = NULL;
1167                                 goto unlock;
1168                         }
1169
1170                         /* Traffic message. Conditionally activate link */
1171                         link_state_event(l_ptr, TRAFFIC_MSG_EVT);
1172
1173                         if (link_working_working(l_ptr)) {
1174                                 /* Re-insert buffer in front of queue */
1175                                 __skb_queue_head(&head, skb);
1176                                 skb = NULL;
1177                                 goto unlock;
1178                         }
1179                         goto unlock;
1180                 }
1181
1182                 /* Link is now in state WORKING_WORKING */
1183                 if (unlikely(seq_no != mod(l_ptr->next_in_no))) {
1184                         link_handle_out_of_seq_msg(l_ptr, skb);
1185                         link_retrieve_defq(l_ptr, &head);
1186                         skb = NULL;
1187                         goto unlock;
1188                 }
1189                 /* Synchronize with parallel link if applicable */
1190                 if (unlikely((l_ptr->flags & LINK_SYNCHING) && !msg_dup(msg))) {
1191                         link_handle_out_of_seq_msg(l_ptr, skb);
1192                         if (link_synch(l_ptr))
1193                                 link_retrieve_defq(l_ptr, &head);
1194                         skb = NULL;
1195                         goto unlock;
1196                 }
1197                 l_ptr->next_in_no++;
1198                 if (unlikely(!skb_queue_empty(&l_ptr->deferdq)))
1199                         link_retrieve_defq(l_ptr, &head);
1200                 if (unlikely(++l_ptr->rcv_unacked >= TIPC_MIN_LINK_WIN)) {
1201                         l_ptr->stats.sent_acks++;
1202                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
1203                 }
1204                 tipc_link_input(l_ptr, skb);
1205                 skb = NULL;
1206 unlock:
1207                 tipc_node_unlock(n_ptr);
1208                 tipc_node_put(n_ptr);
1209 discard:
1210                 if (unlikely(skb))
1211                         kfree_skb(skb);
1212         }
1213 }
1214
1215 /* tipc_data_input - deliver data and name distr msgs to upper layer
1216  *
1217  * Consumes buffer if message is of right type
1218  * Node lock must be held
1219  */
1220 static bool tipc_data_input(struct tipc_link *link, struct sk_buff *skb)
1221 {
1222         struct tipc_node *node = link->owner;
1223         struct tipc_msg *msg = buf_msg(skb);
1224         u32 dport = msg_destport(msg);
1225
1226         switch (msg_user(msg)) {
1227         case TIPC_LOW_IMPORTANCE:
1228         case TIPC_MEDIUM_IMPORTANCE:
1229         case TIPC_HIGH_IMPORTANCE:
1230         case TIPC_CRITICAL_IMPORTANCE:
1231         case CONN_MANAGER:
1232                 if (tipc_skb_queue_tail(&link->inputq, skb, dport)) {
1233                         node->inputq = &link->inputq;
1234                         node->action_flags |= TIPC_MSG_EVT;
1235                 }
1236                 return true;
1237         case NAME_DISTRIBUTOR:
1238                 node->bclink.recv_permitted = true;
1239                 node->namedq = &link->namedq;
1240                 skb_queue_tail(&link->namedq, skb);
1241                 if (skb_queue_len(&link->namedq) == 1)
1242                         node->action_flags |= TIPC_NAMED_MSG_EVT;
1243                 return true;
1244         case MSG_BUNDLER:
1245         case CHANGEOVER_PROTOCOL:
1246         case MSG_FRAGMENTER:
1247         case BCAST_PROTOCOL:
1248                 return false;
1249         default:
1250                 pr_warn("Dropping received illegal msg type\n");
1251                 kfree_skb(skb);
1252                 return false;
1253         };
1254 }
1255
1256 /* tipc_link_input - process packet that has passed link protocol check
1257  *
1258  * Consumes buffer
1259  * Node lock must be held
1260  */
1261 static void tipc_link_input(struct tipc_link *link, struct sk_buff *skb)
1262 {
1263         struct tipc_node *node = link->owner;
1264         struct tipc_msg *msg = buf_msg(skb);
1265         struct sk_buff *iskb;
1266         int pos = 0;
1267
1268         if (likely(tipc_data_input(link, skb)))
1269                 return;
1270
1271         switch (msg_user(msg)) {
1272         case CHANGEOVER_PROTOCOL:
1273                 if (msg_dup(msg)) {
1274                         link->flags |= LINK_SYNCHING;
1275                         link->synch_point = msg_seqno(msg_get_wrapped(msg));
1276                         kfree_skb(skb);
1277                         break;
1278                 }
1279                 if (!tipc_link_failover_rcv(node, &skb))
1280                         break;
1281                 if (msg_user(buf_msg(skb)) != MSG_BUNDLER) {
1282                         tipc_data_input(link, skb);
1283                         break;
1284                 }
1285         case MSG_BUNDLER:
1286                 link->stats.recv_bundles++;
1287                 link->stats.recv_bundled += msg_msgcnt(msg);
1288
1289                 while (tipc_msg_extract(skb, &iskb, &pos))
1290                         tipc_data_input(link, iskb);
1291                 break;
1292         case MSG_FRAGMENTER:
1293                 link->stats.recv_fragments++;
1294                 if (tipc_buf_append(&link->reasm_buf, &skb)) {
1295                         link->stats.recv_fragmented++;
1296                         tipc_data_input(link, skb);
1297                 } else if (!link->reasm_buf) {
1298                         tipc_link_reset(link);
1299                 }
1300                 break;
1301         case BCAST_PROTOCOL:
1302                 tipc_link_sync_rcv(node, skb);
1303                 break;
1304         default:
1305                 break;
1306         };
1307 }
1308
1309 /**
1310  * tipc_link_defer_pkt - Add out-of-sequence message to deferred reception queue
1311  *
1312  * Returns increase in queue length (i.e. 0 or 1)
1313  */
1314 u32 tipc_link_defer_pkt(struct sk_buff_head *list, struct sk_buff *skb)
1315 {
1316         struct sk_buff *skb1;
1317         u32 seq_no = buf_seqno(skb);
1318
1319         /* Empty queue ? */
1320         if (skb_queue_empty(list)) {
1321                 __skb_queue_tail(list, skb);
1322                 return 1;
1323         }
1324
1325         /* Last ? */
1326         if (less(buf_seqno(skb_peek_tail(list)), seq_no)) {
1327                 __skb_queue_tail(list, skb);
1328                 return 1;
1329         }
1330
1331         /* Locate insertion point in queue, then insert; discard if duplicate */
1332         skb_queue_walk(list, skb1) {
1333                 u32 curr_seqno = buf_seqno(skb1);
1334
1335                 if (seq_no == curr_seqno) {
1336                         kfree_skb(skb);
1337                         return 0;
1338                 }
1339
1340                 if (less(seq_no, curr_seqno))
1341                         break;
1342         }
1343
1344         __skb_queue_before(list, skb1, skb);
1345         return 1;
1346 }
1347
1348 /*
1349  * link_handle_out_of_seq_msg - handle arrival of out-of-sequence packet
1350  */
1351 static void link_handle_out_of_seq_msg(struct tipc_link *l_ptr,
1352                                        struct sk_buff *buf)
1353 {
1354         u32 seq_no = buf_seqno(buf);
1355
1356         if (likely(msg_user(buf_msg(buf)) == LINK_PROTOCOL)) {
1357                 tipc_link_proto_rcv(l_ptr, buf);
1358                 return;
1359         }
1360
1361         /* Record OOS packet arrival (force mismatch on next timeout) */
1362         l_ptr->checkpoint--;
1363
1364         /*
1365          * Discard packet if a duplicate; otherwise add it to deferred queue
1366          * and notify peer of gap as per protocol specification
1367          */
1368         if (less(seq_no, mod(l_ptr->next_in_no))) {
1369                 l_ptr->stats.duplicates++;
1370                 kfree_skb(buf);
1371                 return;
1372         }
1373
1374         if (tipc_link_defer_pkt(&l_ptr->deferdq, buf)) {
1375                 l_ptr->stats.deferred_recv++;
1376                 if ((skb_queue_len(&l_ptr->deferdq) % TIPC_MIN_LINK_WIN) == 1)
1377                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
1378         } else {
1379                 l_ptr->stats.duplicates++;
1380         }
1381 }
1382
1383 /*
1384  * Send protocol message to the other endpoint.
1385  */
1386 void tipc_link_proto_xmit(struct tipc_link *l_ptr, u32 msg_typ, int probe_msg,
1387                           u32 gap, u32 tolerance, u32 priority, u32 ack_mtu)
1388 {
1389         struct sk_buff *buf = NULL;
1390         struct tipc_msg *msg = l_ptr->pmsg;
1391         u32 msg_size = sizeof(l_ptr->proto_msg);
1392         int r_flag;
1393
1394         /* Don't send protocol message during link changeover */
1395         if (l_ptr->exp_msg_count)
1396                 return;
1397
1398         /* Abort non-RESET send if communication with node is prohibited */
1399         if ((tipc_node_blocked(l_ptr->owner)) && (msg_typ != RESET_MSG))
1400                 return;
1401
1402         /* Create protocol message with "out-of-sequence" sequence number */
1403         msg_set_type(msg, msg_typ);
1404         msg_set_net_plane(msg, l_ptr->net_plane);
1405         msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1406         msg_set_last_bcast(msg, tipc_bclink_get_last_sent(l_ptr->owner->net));
1407
1408         if (msg_typ == STATE_MSG) {
1409                 u32 next_sent = mod(l_ptr->next_out_no);
1410
1411                 if (!tipc_link_is_up(l_ptr))
1412                         return;
1413                 if (skb_queue_len(&l_ptr->backlogq))
1414                         next_sent = buf_seqno(skb_peek(&l_ptr->backlogq));
1415                 msg_set_next_sent(msg, next_sent);
1416                 if (!skb_queue_empty(&l_ptr->deferdq)) {
1417                         u32 rec = buf_seqno(skb_peek(&l_ptr->deferdq));
1418                         gap = mod(rec - mod(l_ptr->next_in_no));
1419                 }
1420                 msg_set_seq_gap(msg, gap);
1421                 if (gap)
1422                         l_ptr->stats.sent_nacks++;
1423                 msg_set_link_tolerance(msg, tolerance);
1424                 msg_set_linkprio(msg, priority);
1425                 msg_set_max_pkt(msg, ack_mtu);
1426                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1427                 msg_set_probe(msg, probe_msg != 0);
1428                 if (probe_msg) {
1429                         u32 mtu = l_ptr->max_pkt;
1430
1431                         if ((mtu < l_ptr->max_pkt_target) &&
1432                             link_working_working(l_ptr) &&
1433                             l_ptr->fsm_msg_cnt) {
1434                                 msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
1435                                 if (l_ptr->max_pkt_probes == 10) {
1436                                         l_ptr->max_pkt_target = (msg_size - 4);
1437                                         l_ptr->max_pkt_probes = 0;
1438                                         msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
1439                                 }
1440                                 l_ptr->max_pkt_probes++;
1441                         }
1442
1443                         l_ptr->stats.sent_probes++;
1444                 }
1445                 l_ptr->stats.sent_states++;
1446         } else {                /* RESET_MSG or ACTIVATE_MSG */
1447                 msg_set_ack(msg, mod(l_ptr->reset_checkpoint - 1));
1448                 msg_set_seq_gap(msg, 0);
1449                 msg_set_next_sent(msg, 1);
1450                 msg_set_probe(msg, 0);
1451                 msg_set_link_tolerance(msg, l_ptr->tolerance);
1452                 msg_set_linkprio(msg, l_ptr->priority);
1453                 msg_set_max_pkt(msg, l_ptr->max_pkt_target);
1454         }
1455
1456         r_flag = (l_ptr->owner->working_links > tipc_link_is_up(l_ptr));
1457         msg_set_redundant_link(msg, r_flag);
1458         msg_set_linkprio(msg, l_ptr->priority);
1459         msg_set_size(msg, msg_size);
1460
1461         msg_set_seqno(msg, mod(l_ptr->next_out_no + (0xffff/2)));
1462
1463         buf = tipc_buf_acquire(msg_size);
1464         if (!buf)
1465                 return;
1466
1467         skb_copy_to_linear_data(buf, msg, sizeof(l_ptr->proto_msg));
1468         buf->priority = TC_PRIO_CONTROL;
1469         tipc_bearer_send(l_ptr->owner->net, l_ptr->bearer_id, buf,
1470                          &l_ptr->media_addr);
1471         l_ptr->rcv_unacked = 0;
1472         kfree_skb(buf);
1473 }
1474
1475 /*
1476  * Receive protocol message :
1477  * Note that network plane id propagates through the network, and may
1478  * change at any time. The node with lowest address rules
1479  */
1480 static void tipc_link_proto_rcv(struct tipc_link *l_ptr,
1481                                 struct sk_buff *buf)
1482 {
1483         u32 rec_gap = 0;
1484         u32 max_pkt_info;
1485         u32 max_pkt_ack;
1486         u32 msg_tol;
1487         struct tipc_msg *msg = buf_msg(buf);
1488
1489         /* Discard protocol message during link changeover */
1490         if (l_ptr->exp_msg_count)
1491                 goto exit;
1492
1493         if (l_ptr->net_plane != msg_net_plane(msg))
1494                 if (link_own_addr(l_ptr) > msg_prevnode(msg))
1495                         l_ptr->net_plane = msg_net_plane(msg);
1496
1497         switch (msg_type(msg)) {
1498
1499         case RESET_MSG:
1500                 if (!link_working_unknown(l_ptr) &&
1501                     (l_ptr->peer_session != INVALID_SESSION)) {
1502                         if (less_eq(msg_session(msg), l_ptr->peer_session))
1503                                 break; /* duplicate or old reset: ignore */
1504                 }
1505
1506                 if (!msg_redundant_link(msg) && (link_working_working(l_ptr) ||
1507                                 link_working_unknown(l_ptr))) {
1508                         /*
1509                          * peer has lost contact -- don't allow peer's links
1510                          * to reactivate before we recognize loss & clean up
1511                          */
1512                         l_ptr->owner->action_flags |= TIPC_WAIT_OWN_LINKS_DOWN;
1513                 }
1514
1515                 link_state_event(l_ptr, RESET_MSG);
1516
1517                 /* fall thru' */
1518         case ACTIVATE_MSG:
1519                 /* Update link settings according other endpoint's values */
1520                 strcpy((strrchr(l_ptr->name, ':') + 1), (char *)msg_data(msg));
1521
1522                 msg_tol = msg_link_tolerance(msg);
1523                 if (msg_tol > l_ptr->tolerance)
1524                         link_set_supervision_props(l_ptr, msg_tol);
1525
1526                 if (msg_linkprio(msg) > l_ptr->priority)
1527                         l_ptr->priority = msg_linkprio(msg);
1528
1529                 max_pkt_info = msg_max_pkt(msg);
1530                 if (max_pkt_info) {
1531                         if (max_pkt_info < l_ptr->max_pkt_target)
1532                                 l_ptr->max_pkt_target = max_pkt_info;
1533                         if (l_ptr->max_pkt > l_ptr->max_pkt_target)
1534                                 l_ptr->max_pkt = l_ptr->max_pkt_target;
1535                 } else {
1536                         l_ptr->max_pkt = l_ptr->max_pkt_target;
1537                 }
1538
1539                 /* Synchronize broadcast link info, if not done previously */
1540                 if (!tipc_node_is_up(l_ptr->owner)) {
1541                         l_ptr->owner->bclink.last_sent =
1542                                 l_ptr->owner->bclink.last_in =
1543                                 msg_last_bcast(msg);
1544                         l_ptr->owner->bclink.oos_state = 0;
1545                 }
1546
1547                 l_ptr->peer_session = msg_session(msg);
1548                 l_ptr->peer_bearer_id = msg_bearer_id(msg);
1549
1550                 if (msg_type(msg) == ACTIVATE_MSG)
1551                         link_state_event(l_ptr, ACTIVATE_MSG);
1552                 break;
1553         case STATE_MSG:
1554
1555                 msg_tol = msg_link_tolerance(msg);
1556                 if (msg_tol)
1557                         link_set_supervision_props(l_ptr, msg_tol);
1558
1559                 if (msg_linkprio(msg) &&
1560                     (msg_linkprio(msg) != l_ptr->priority)) {
1561                         pr_debug("%s<%s>, priority change %u->%u\n",
1562                                  link_rst_msg, l_ptr->name,
1563                                  l_ptr->priority, msg_linkprio(msg));
1564                         l_ptr->priority = msg_linkprio(msg);
1565                         tipc_link_reset(l_ptr); /* Enforce change to take effect */
1566                         break;
1567                 }
1568
1569                 /* Record reception; force mismatch at next timeout: */
1570                 l_ptr->checkpoint--;
1571
1572                 link_state_event(l_ptr, TRAFFIC_MSG_EVT);
1573                 l_ptr->stats.recv_states++;
1574                 if (link_reset_unknown(l_ptr))
1575                         break;
1576
1577                 if (less_eq(mod(l_ptr->next_in_no), msg_next_sent(msg))) {
1578                         rec_gap = mod(msg_next_sent(msg) -
1579                                       mod(l_ptr->next_in_no));
1580                 }
1581
1582                 max_pkt_ack = msg_max_pkt(msg);
1583                 if (max_pkt_ack > l_ptr->max_pkt) {
1584                         l_ptr->max_pkt = max_pkt_ack;
1585                         l_ptr->max_pkt_probes = 0;
1586                 }
1587
1588                 max_pkt_ack = 0;
1589                 if (msg_probe(msg)) {
1590                         l_ptr->stats.recv_probes++;
1591                         if (msg_size(msg) > sizeof(l_ptr->proto_msg))
1592                                 max_pkt_ack = msg_size(msg);
1593                 }
1594
1595                 /* Protocol message before retransmits, reduce loss risk */
1596                 if (l_ptr->owner->bclink.recv_permitted)
1597                         tipc_bclink_update_link_state(l_ptr->owner,
1598                                                       msg_last_bcast(msg));
1599
1600                 if (rec_gap || (msg_probe(msg))) {
1601                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, rec_gap, 0,
1602                                              0, max_pkt_ack);
1603                 }
1604                 if (msg_seq_gap(msg)) {
1605                         l_ptr->stats.recv_nacks++;
1606                         tipc_link_retransmit(l_ptr, skb_peek(&l_ptr->transmq),
1607                                              msg_seq_gap(msg));
1608                 }
1609                 break;
1610         }
1611 exit:
1612         kfree_skb(buf);
1613 }
1614
1615
1616 /* tipc_link_tunnel_xmit(): Tunnel one packet via a link belonging to
1617  * a different bearer. Owner node is locked.
1618  */
1619 static void tipc_link_tunnel_xmit(struct tipc_link *l_ptr,
1620                                   struct tipc_msg *tunnel_hdr,
1621                                   struct tipc_msg *msg,
1622                                   u32 selector)
1623 {
1624         struct tipc_link *tunnel;
1625         struct sk_buff *skb;
1626         u32 length = msg_size(msg);
1627
1628         tunnel = l_ptr->owner->active_links[selector & 1];
1629         if (!tipc_link_is_up(tunnel)) {
1630                 pr_warn("%stunnel link no longer available\n", link_co_err);
1631                 return;
1632         }
1633         msg_set_size(tunnel_hdr, length + INT_H_SIZE);
1634         skb = tipc_buf_acquire(length + INT_H_SIZE);
1635         if (!skb) {
1636                 pr_warn("%sunable to send tunnel msg\n", link_co_err);
1637                 return;
1638         }
1639         skb_copy_to_linear_data(skb, tunnel_hdr, INT_H_SIZE);
1640         skb_copy_to_linear_data_offset(skb, INT_H_SIZE, msg, length);
1641         __tipc_link_xmit_skb(tunnel, skb);
1642 }
1643
1644
1645 /* tipc_link_failover_send_queue(): A link has gone down, but a second
1646  * link is still active. We can do failover. Tunnel the failing link's
1647  * whole send queue via the remaining link. This way, we don't lose
1648  * any packets, and sequence order is preserved for subsequent traffic
1649  * sent over the remaining link. Owner node is locked.
1650  */
1651 void tipc_link_failover_send_queue(struct tipc_link *l_ptr)
1652 {
1653         int msgcount;
1654         struct tipc_link *tunnel = l_ptr->owner->active_links[0];
1655         struct tipc_msg tunnel_hdr;
1656         struct sk_buff *skb;
1657         int split_bundles;
1658
1659         if (!tunnel)
1660                 return;
1661
1662         tipc_msg_init(link_own_addr(l_ptr), &tunnel_hdr, CHANGEOVER_PROTOCOL,
1663                       ORIGINAL_MSG, INT_H_SIZE, l_ptr->addr);
1664         skb_queue_splice_tail_init(&l_ptr->backlogq, &l_ptr->transmq);
1665         tipc_link_purge_backlog(l_ptr);
1666         msgcount = skb_queue_len(&l_ptr->transmq);
1667         msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
1668         msg_set_msgcnt(&tunnel_hdr, msgcount);
1669
1670         if (skb_queue_empty(&l_ptr->transmq)) {
1671                 skb = tipc_buf_acquire(INT_H_SIZE);
1672                 if (skb) {
1673                         skb_copy_to_linear_data(skb, &tunnel_hdr, INT_H_SIZE);
1674                         msg_set_size(&tunnel_hdr, INT_H_SIZE);
1675                         __tipc_link_xmit_skb(tunnel, skb);
1676                 } else {
1677                         pr_warn("%sunable to send changeover msg\n",
1678                                 link_co_err);
1679                 }
1680                 return;
1681         }
1682
1683         split_bundles = (l_ptr->owner->active_links[0] !=
1684                          l_ptr->owner->active_links[1]);
1685
1686         skb_queue_walk(&l_ptr->transmq, skb) {
1687                 struct tipc_msg *msg = buf_msg(skb);
1688
1689                 if ((msg_user(msg) == MSG_BUNDLER) && split_bundles) {
1690                         struct tipc_msg *m = msg_get_wrapped(msg);
1691                         unchar *pos = (unchar *)m;
1692
1693                         msgcount = msg_msgcnt(msg);
1694                         while (msgcount--) {
1695                                 msg_set_seqno(m, msg_seqno(msg));
1696                                 tipc_link_tunnel_xmit(l_ptr, &tunnel_hdr, m,
1697                                                       msg_link_selector(m));
1698                                 pos += align(msg_size(m));
1699                                 m = (struct tipc_msg *)pos;
1700                         }
1701                 } else {
1702                         tipc_link_tunnel_xmit(l_ptr, &tunnel_hdr, msg,
1703                                               msg_link_selector(msg));
1704                 }
1705         }
1706 }
1707
1708 /* tipc_link_dup_queue_xmit(): A second link has become active. Tunnel a
1709  * duplicate of the first link's send queue via the new link. This way, we
1710  * are guaranteed that currently queued packets from a socket are delivered
1711  * before future traffic from the same socket, even if this is using the
1712  * new link. The last arriving copy of each duplicate packet is dropped at
1713  * the receiving end by the regular protocol check, so packet cardinality
1714  * and sequence order is preserved per sender/receiver socket pair.
1715  * Owner node is locked.
1716  */
1717 void tipc_link_dup_queue_xmit(struct tipc_link *link,
1718                               struct tipc_link *tnl)
1719 {
1720         struct sk_buff *skb;
1721         struct tipc_msg tnl_hdr;
1722         struct sk_buff_head *queue = &link->transmq;
1723         int mcnt;
1724
1725         tipc_msg_init(link_own_addr(link), &tnl_hdr, CHANGEOVER_PROTOCOL,
1726                       DUPLICATE_MSG, INT_H_SIZE, link->addr);
1727         mcnt = skb_queue_len(&link->transmq) + skb_queue_len(&link->backlogq);
1728         msg_set_msgcnt(&tnl_hdr, mcnt);
1729         msg_set_bearer_id(&tnl_hdr, link->peer_bearer_id);
1730
1731 tunnel_queue:
1732         skb_queue_walk(queue, skb) {
1733                 struct sk_buff *outskb;
1734                 struct tipc_msg *msg = buf_msg(skb);
1735                 u32 len = msg_size(msg);
1736
1737                 msg_set_ack(msg, mod(link->next_in_no - 1));
1738                 msg_set_bcast_ack(msg, link->owner->bclink.last_in);
1739                 msg_set_size(&tnl_hdr, len + INT_H_SIZE);
1740                 outskb = tipc_buf_acquire(len + INT_H_SIZE);
1741                 if (outskb == NULL) {
1742                         pr_warn("%sunable to send duplicate msg\n",
1743                                 link_co_err);
1744                         return;
1745                 }
1746                 skb_copy_to_linear_data(outskb, &tnl_hdr, INT_H_SIZE);
1747                 skb_copy_to_linear_data_offset(outskb, INT_H_SIZE,
1748                                                skb->data, len);
1749                 __tipc_link_xmit_skb(tnl, outskb);
1750                 if (!tipc_link_is_up(link))
1751                         return;
1752         }
1753         if (queue == &link->backlogq)
1754                 return;
1755         queue = &link->backlogq;
1756         goto tunnel_queue;
1757 }
1758
1759 /*  tipc_link_failover_rcv(): Receive a tunnelled ORIGINAL_MSG packet
1760  *  Owner node is locked.
1761  */
1762 static bool tipc_link_failover_rcv(struct tipc_node *node,
1763                                    struct sk_buff **skb)
1764 {
1765         struct tipc_msg *msg = buf_msg(*skb);
1766         struct sk_buff *iskb = NULL;
1767         struct tipc_link *link = NULL;
1768         int bearer_id = msg_bearer_id(msg);
1769         int pos = 0;
1770
1771         if (msg_type(msg) != ORIGINAL_MSG) {
1772                 pr_warn("%sunknown tunnel pkt received\n", link_co_err);
1773                 goto exit;
1774         }
1775         if (bearer_id >= MAX_BEARERS)
1776                 goto exit;
1777         link = node->links[bearer_id];
1778         if (!link)
1779                 goto exit;
1780         if (tipc_link_is_up(link))
1781                 tipc_link_reset(link);
1782
1783         /* First failover packet? */
1784         if (link->exp_msg_count == START_CHANGEOVER)
1785                 link->exp_msg_count = msg_msgcnt(msg);
1786
1787         /* Should we expect an inner packet? */
1788         if (!link->exp_msg_count)
1789                 goto exit;
1790
1791         if (!tipc_msg_extract(*skb, &iskb, &pos)) {
1792                 pr_warn("%sno inner failover pkt\n", link_co_err);
1793                 *skb = NULL;
1794                 goto exit;
1795         }
1796         link->exp_msg_count--;
1797         *skb = NULL;
1798
1799         /* Was packet already delivered? */
1800         if (less(buf_seqno(iskb), link->reset_checkpoint)) {
1801                 kfree_skb(iskb);
1802                 iskb = NULL;
1803                 goto exit;
1804         }
1805         if (msg_user(buf_msg(iskb)) == MSG_FRAGMENTER) {
1806                 link->stats.recv_fragments++;
1807                 tipc_buf_append(&link->reasm_buf, &iskb);
1808         }
1809 exit:
1810         if (link && (!link->exp_msg_count) && (link->flags & LINK_STOPPED))
1811                 tipc_link_delete(link);
1812         kfree_skb(*skb);
1813         *skb = iskb;
1814         return *skb;
1815 }
1816
1817 static void link_set_supervision_props(struct tipc_link *l_ptr, u32 tol)
1818 {
1819         unsigned long intv = ((tol / 4) > 500) ? 500 : tol / 4;
1820
1821         if ((tol < TIPC_MIN_LINK_TOL) || (tol > TIPC_MAX_LINK_TOL))
1822                 return;
1823
1824         l_ptr->tolerance = tol;
1825         l_ptr->cont_intv = msecs_to_jiffies(intv);
1826         l_ptr->abort_limit = tol / (jiffies_to_msecs(l_ptr->cont_intv) / 4);
1827 }
1828
1829 void tipc_link_set_queue_limits(struct tipc_link *l, u32 win)
1830 {
1831         int max_bulk = TIPC_MAX_PUBLICATIONS / (l->max_pkt / ITEM_SIZE);
1832
1833         l->window = win;
1834         l->backlog[TIPC_LOW_IMPORTANCE].limit      = win / 2;
1835         l->backlog[TIPC_MEDIUM_IMPORTANCE].limit   = win;
1836         l->backlog[TIPC_HIGH_IMPORTANCE].limit     = win / 2 * 3;
1837         l->backlog[TIPC_CRITICAL_IMPORTANCE].limit = win * 2;
1838         l->backlog[TIPC_SYSTEM_IMPORTANCE].limit   = max_bulk;
1839 }
1840
1841 /* tipc_link_find_owner - locate owner node of link by link's name
1842  * @net: the applicable net namespace
1843  * @name: pointer to link name string
1844  * @bearer_id: pointer to index in 'node->links' array where the link was found.
1845  *
1846  * Returns pointer to node owning the link, or 0 if no matching link is found.
1847  */
1848 static struct tipc_node *tipc_link_find_owner(struct net *net,
1849                                               const char *link_name,
1850                                               unsigned int *bearer_id)
1851 {
1852         struct tipc_net *tn = net_generic(net, tipc_net_id);
1853         struct tipc_link *l_ptr;
1854         struct tipc_node *n_ptr;
1855         struct tipc_node *found_node = NULL;
1856         int i;
1857
1858         *bearer_id = 0;
1859         rcu_read_lock();
1860         list_for_each_entry_rcu(n_ptr, &tn->node_list, list) {
1861                 tipc_node_lock(n_ptr);
1862                 for (i = 0; i < MAX_BEARERS; i++) {
1863                         l_ptr = n_ptr->links[i];
1864                         if (l_ptr && !strcmp(l_ptr->name, link_name)) {
1865                                 *bearer_id = i;
1866                                 found_node = n_ptr;
1867                                 break;
1868                         }
1869                 }
1870                 tipc_node_unlock(n_ptr);
1871                 if (found_node)
1872                         break;
1873         }
1874         rcu_read_unlock();
1875
1876         return found_node;
1877 }
1878
1879 /**
1880  * link_reset_statistics - reset link statistics
1881  * @l_ptr: pointer to link
1882  */
1883 static void link_reset_statistics(struct tipc_link *l_ptr)
1884 {
1885         memset(&l_ptr->stats, 0, sizeof(l_ptr->stats));
1886         l_ptr->stats.sent_info = l_ptr->next_out_no;
1887         l_ptr->stats.recv_info = l_ptr->next_in_no;
1888 }
1889
1890 static void link_print(struct tipc_link *l_ptr, const char *str)
1891 {
1892         struct tipc_net *tn = net_generic(l_ptr->owner->net, tipc_net_id);
1893         struct tipc_bearer *b_ptr;
1894
1895         rcu_read_lock();
1896         b_ptr = rcu_dereference_rtnl(tn->bearer_list[l_ptr->bearer_id]);
1897         if (b_ptr)
1898                 pr_info("%s Link %x<%s>:", str, l_ptr->addr, b_ptr->name);
1899         rcu_read_unlock();
1900
1901         if (link_working_unknown(l_ptr))
1902                 pr_cont(":WU\n");
1903         else if (link_reset_reset(l_ptr))
1904                 pr_cont(":RR\n");
1905         else if (link_reset_unknown(l_ptr))
1906                 pr_cont(":RU\n");
1907         else if (link_working_working(l_ptr))
1908                 pr_cont(":WW\n");
1909         else
1910                 pr_cont("\n");
1911 }
1912
1913 /* Parse and validate nested (link) properties valid for media, bearer and link
1914  */
1915 int tipc_nl_parse_link_prop(struct nlattr *prop, struct nlattr *props[])
1916 {
1917         int err;
1918
1919         err = nla_parse_nested(props, TIPC_NLA_PROP_MAX, prop,
1920                                tipc_nl_prop_policy);
1921         if (err)
1922                 return err;
1923
1924         if (props[TIPC_NLA_PROP_PRIO]) {
1925                 u32 prio;
1926
1927                 prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
1928                 if (prio > TIPC_MAX_LINK_PRI)
1929                         return -EINVAL;
1930         }
1931
1932         if (props[TIPC_NLA_PROP_TOL]) {
1933                 u32 tol;
1934
1935                 tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
1936                 if ((tol < TIPC_MIN_LINK_TOL) || (tol > TIPC_MAX_LINK_TOL))
1937                         return -EINVAL;
1938         }
1939
1940         if (props[TIPC_NLA_PROP_WIN]) {
1941                 u32 win;
1942
1943                 win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
1944                 if ((win < TIPC_MIN_LINK_WIN) || (win > TIPC_MAX_LINK_WIN))
1945                         return -EINVAL;
1946         }
1947
1948         return 0;
1949 }
1950
1951 int tipc_nl_link_set(struct sk_buff *skb, struct genl_info *info)
1952 {
1953         int err;
1954         int res = 0;
1955         int bearer_id;
1956         char *name;
1957         struct tipc_link *link;
1958         struct tipc_node *node;
1959         struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
1960         struct net *net = sock_net(skb->sk);
1961
1962         if (!info->attrs[TIPC_NLA_LINK])
1963                 return -EINVAL;
1964
1965         err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
1966                                info->attrs[TIPC_NLA_LINK],
1967                                tipc_nl_link_policy);
1968         if (err)
1969                 return err;
1970
1971         if (!attrs[TIPC_NLA_LINK_NAME])
1972                 return -EINVAL;
1973
1974         name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
1975
1976         node = tipc_link_find_owner(net, name, &bearer_id);
1977         if (!node)
1978                 return -EINVAL;
1979
1980         tipc_node_lock(node);
1981
1982         link = node->links[bearer_id];
1983         if (!link) {
1984                 res = -EINVAL;
1985                 goto out;
1986         }
1987
1988         if (attrs[TIPC_NLA_LINK_PROP]) {
1989                 struct nlattr *props[TIPC_NLA_PROP_MAX + 1];
1990
1991                 err = tipc_nl_parse_link_prop(attrs[TIPC_NLA_LINK_PROP],
1992                                               props);
1993                 if (err) {
1994                         res = err;
1995                         goto out;
1996                 }
1997
1998                 if (props[TIPC_NLA_PROP_TOL]) {
1999                         u32 tol;
2000
2001                         tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
2002                         link_set_supervision_props(link, tol);
2003                         tipc_link_proto_xmit(link, STATE_MSG, 0, 0, tol, 0, 0);
2004                 }
2005                 if (props[TIPC_NLA_PROP_PRIO]) {
2006                         u32 prio;
2007
2008                         prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
2009                         link->priority = prio;
2010                         tipc_link_proto_xmit(link, STATE_MSG, 0, 0, 0, prio, 0);
2011                 }
2012                 if (props[TIPC_NLA_PROP_WIN]) {
2013                         u32 win;
2014
2015                         win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
2016                         tipc_link_set_queue_limits(link, win);
2017                 }
2018         }
2019
2020 out:
2021         tipc_node_unlock(node);
2022
2023         return res;
2024 }
2025
2026 static int __tipc_nl_add_stats(struct sk_buff *skb, struct tipc_stats *s)
2027 {
2028         int i;
2029         struct nlattr *stats;
2030
2031         struct nla_map {
2032                 u32 key;
2033                 u32 val;
2034         };
2035
2036         struct nla_map map[] = {
2037                 {TIPC_NLA_STATS_RX_INFO, s->recv_info},
2038                 {TIPC_NLA_STATS_RX_FRAGMENTS, s->recv_fragments},
2039                 {TIPC_NLA_STATS_RX_FRAGMENTED, s->recv_fragmented},
2040                 {TIPC_NLA_STATS_RX_BUNDLES, s->recv_bundles},
2041                 {TIPC_NLA_STATS_RX_BUNDLED, s->recv_bundled},
2042                 {TIPC_NLA_STATS_TX_INFO, s->sent_info},
2043                 {TIPC_NLA_STATS_TX_FRAGMENTS, s->sent_fragments},
2044                 {TIPC_NLA_STATS_TX_FRAGMENTED, s->sent_fragmented},
2045                 {TIPC_NLA_STATS_TX_BUNDLES, s->sent_bundles},
2046                 {TIPC_NLA_STATS_TX_BUNDLED, s->sent_bundled},
2047                 {TIPC_NLA_STATS_MSG_PROF_TOT, (s->msg_length_counts) ?
2048                         s->msg_length_counts : 1},
2049                 {TIPC_NLA_STATS_MSG_LEN_CNT, s->msg_length_counts},
2050                 {TIPC_NLA_STATS_MSG_LEN_TOT, s->msg_lengths_total},
2051                 {TIPC_NLA_STATS_MSG_LEN_P0, s->msg_length_profile[0]},
2052                 {TIPC_NLA_STATS_MSG_LEN_P1, s->msg_length_profile[1]},
2053                 {TIPC_NLA_STATS_MSG_LEN_P2, s->msg_length_profile[2]},
2054                 {TIPC_NLA_STATS_MSG_LEN_P3, s->msg_length_profile[3]},
2055                 {TIPC_NLA_STATS_MSG_LEN_P4, s->msg_length_profile[4]},
2056                 {TIPC_NLA_STATS_MSG_LEN_P5, s->msg_length_profile[5]},
2057                 {TIPC_NLA_STATS_MSG_LEN_P6, s->msg_length_profile[6]},
2058                 {TIPC_NLA_STATS_RX_STATES, s->recv_states},
2059                 {TIPC_NLA_STATS_RX_PROBES, s->recv_probes},
2060                 {TIPC_NLA_STATS_RX_NACKS, s->recv_nacks},
2061                 {TIPC_NLA_STATS_RX_DEFERRED, s->deferred_recv},
2062                 {TIPC_NLA_STATS_TX_STATES, s->sent_states},
2063                 {TIPC_NLA_STATS_TX_PROBES, s->sent_probes},
2064                 {TIPC_NLA_STATS_TX_NACKS, s->sent_nacks},
2065                 {TIPC_NLA_STATS_TX_ACKS, s->sent_acks},
2066                 {TIPC_NLA_STATS_RETRANSMITTED, s->retransmitted},
2067                 {TIPC_NLA_STATS_DUPLICATES, s->duplicates},
2068                 {TIPC_NLA_STATS_LINK_CONGS, s->link_congs},
2069                 {TIPC_NLA_STATS_MAX_QUEUE, s->max_queue_sz},
2070                 {TIPC_NLA_STATS_AVG_QUEUE, s->queue_sz_counts ?
2071                         (s->accu_queue_sz / s->queue_sz_counts) : 0}
2072         };
2073
2074         stats = nla_nest_start(skb, TIPC_NLA_LINK_STATS);
2075         if (!stats)
2076                 return -EMSGSIZE;
2077
2078         for (i = 0; i <  ARRAY_SIZE(map); i++)
2079                 if (nla_put_u32(skb, map[i].key, map[i].val))
2080                         goto msg_full;
2081
2082         nla_nest_end(skb, stats);
2083
2084         return 0;
2085 msg_full:
2086         nla_nest_cancel(skb, stats);
2087
2088         return -EMSGSIZE;
2089 }
2090
2091 /* Caller should hold appropriate locks to protect the link */
2092 static int __tipc_nl_add_link(struct net *net, struct tipc_nl_msg *msg,
2093                               struct tipc_link *link)
2094 {
2095         int err;
2096         void *hdr;
2097         struct nlattr *attrs;
2098         struct nlattr *prop;
2099         struct tipc_net *tn = net_generic(net, tipc_net_id);
2100
2101         hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
2102                           NLM_F_MULTI, TIPC_NL_LINK_GET);
2103         if (!hdr)
2104                 return -EMSGSIZE;
2105
2106         attrs = nla_nest_start(msg->skb, TIPC_NLA_LINK);
2107         if (!attrs)
2108                 goto msg_full;
2109
2110         if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, link->name))
2111                 goto attr_msg_full;
2112         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_DEST,
2113                         tipc_cluster_mask(tn->own_addr)))
2114                 goto attr_msg_full;
2115         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_MTU, link->max_pkt))
2116                 goto attr_msg_full;
2117         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, link->next_in_no))
2118                 goto attr_msg_full;
2119         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, link->next_out_no))
2120                 goto attr_msg_full;
2121
2122         if (tipc_link_is_up(link))
2123                 if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
2124                         goto attr_msg_full;
2125         if (tipc_link_is_active(link))
2126                 if (nla_put_flag(msg->skb, TIPC_NLA_LINK_ACTIVE))
2127                         goto attr_msg_full;
2128
2129         prop = nla_nest_start(msg->skb, TIPC_NLA_LINK_PROP);
2130         if (!prop)
2131                 goto attr_msg_full;
2132         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
2133                 goto prop_msg_full;
2134         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_TOL, link->tolerance))
2135                 goto prop_msg_full;
2136         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN,
2137                         link->window))
2138                 goto prop_msg_full;
2139         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
2140                 goto prop_msg_full;
2141         nla_nest_end(msg->skb, prop);
2142
2143         err = __tipc_nl_add_stats(msg->skb, &link->stats);
2144         if (err)
2145                 goto attr_msg_full;
2146
2147         nla_nest_end(msg->skb, attrs);
2148         genlmsg_end(msg->skb, hdr);
2149
2150         return 0;
2151
2152 prop_msg_full:
2153         nla_nest_cancel(msg->skb, prop);
2154 attr_msg_full:
2155         nla_nest_cancel(msg->skb, attrs);
2156 msg_full:
2157         genlmsg_cancel(msg->skb, hdr);
2158
2159         return -EMSGSIZE;
2160 }
2161
2162 /* Caller should hold node lock  */
2163 static int __tipc_nl_add_node_links(struct net *net, struct tipc_nl_msg *msg,
2164                                     struct tipc_node *node, u32 *prev_link)
2165 {
2166         u32 i;
2167         int err;
2168
2169         for (i = *prev_link; i < MAX_BEARERS; i++) {
2170                 *prev_link = i;
2171
2172                 if (!node->links[i])
2173                         continue;
2174
2175                 err = __tipc_nl_add_link(net, msg, node->links[i]);
2176                 if (err)
2177                         return err;
2178         }
2179         *prev_link = 0;
2180
2181         return 0;
2182 }
2183
2184 int tipc_nl_link_dump(struct sk_buff *skb, struct netlink_callback *cb)
2185 {
2186         struct net *net = sock_net(skb->sk);
2187         struct tipc_net *tn = net_generic(net, tipc_net_id);
2188         struct tipc_node *node;
2189         struct tipc_nl_msg msg;
2190         u32 prev_node = cb->args[0];
2191         u32 prev_link = cb->args[1];
2192         int done = cb->args[2];
2193         int err;
2194
2195         if (done)
2196                 return 0;
2197
2198         msg.skb = skb;
2199         msg.portid = NETLINK_CB(cb->skb).portid;
2200         msg.seq = cb->nlh->nlmsg_seq;
2201
2202         rcu_read_lock();
2203         if (prev_node) {
2204                 node = tipc_node_find(net, prev_node);
2205                 if (!node) {
2206                         /* We never set seq or call nl_dump_check_consistent()
2207                          * this means that setting prev_seq here will cause the
2208                          * consistence check to fail in the netlink callback
2209                          * handler. Resulting in the last NLMSG_DONE message
2210                          * having the NLM_F_DUMP_INTR flag set.
2211                          */
2212                         cb->prev_seq = 1;
2213                         goto out;
2214                 }
2215                 tipc_node_put(node);
2216
2217                 list_for_each_entry_continue_rcu(node, &tn->node_list,
2218                                                  list) {
2219                         tipc_node_lock(node);
2220                         err = __tipc_nl_add_node_links(net, &msg, node,
2221                                                        &prev_link);
2222                         tipc_node_unlock(node);
2223                         tipc_node_put(node);
2224                         if (err)
2225                                 goto out;
2226
2227                         prev_node = node->addr;
2228                 }
2229         } else {
2230                 err = tipc_nl_add_bc_link(net, &msg);
2231                 if (err)
2232                         goto out;
2233
2234                 list_for_each_entry_rcu(node, &tn->node_list, list) {
2235                         tipc_node_lock(node);
2236                         err = __tipc_nl_add_node_links(net, &msg, node,
2237                                                        &prev_link);
2238                         tipc_node_unlock(node);
2239                         if (err)
2240                                 goto out;
2241
2242                         prev_node = node->addr;
2243                 }
2244         }
2245         done = 1;
2246 out:
2247         rcu_read_unlock();
2248
2249         cb->args[0] = prev_node;
2250         cb->args[1] = prev_link;
2251         cb->args[2] = done;
2252
2253         return skb->len;
2254 }
2255
2256 int tipc_nl_link_get(struct sk_buff *skb, struct genl_info *info)
2257 {
2258         struct net *net = genl_info_net(info);
2259         struct sk_buff *ans_skb;
2260         struct tipc_nl_msg msg;
2261         struct tipc_link *link;
2262         struct tipc_node *node;
2263         char *name;
2264         int bearer_id;
2265         int err;
2266
2267         if (!info->attrs[TIPC_NLA_LINK_NAME])
2268                 return -EINVAL;
2269
2270         name = nla_data(info->attrs[TIPC_NLA_LINK_NAME]);
2271         node = tipc_link_find_owner(net, name, &bearer_id);
2272         if (!node)
2273                 return -EINVAL;
2274
2275         ans_skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
2276         if (!ans_skb)
2277                 return -ENOMEM;
2278
2279         msg.skb = ans_skb;
2280         msg.portid = info->snd_portid;
2281         msg.seq = info->snd_seq;
2282
2283         tipc_node_lock(node);
2284         link = node->links[bearer_id];
2285         if (!link) {
2286                 err = -EINVAL;
2287                 goto err_out;
2288         }
2289
2290         err = __tipc_nl_add_link(net, &msg, link);
2291         if (err)
2292                 goto err_out;
2293
2294         tipc_node_unlock(node);
2295
2296         return genlmsg_reply(ans_skb, info);
2297
2298 err_out:
2299         tipc_node_unlock(node);
2300         nlmsg_free(ans_skb);
2301
2302         return err;
2303 }
2304
2305 int tipc_nl_link_reset_stats(struct sk_buff *skb, struct genl_info *info)
2306 {
2307         int err;
2308         char *link_name;
2309         unsigned int bearer_id;
2310         struct tipc_link *link;
2311         struct tipc_node *node;
2312         struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
2313         struct net *net = sock_net(skb->sk);
2314
2315         if (!info->attrs[TIPC_NLA_LINK])
2316                 return -EINVAL;
2317
2318         err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
2319                                info->attrs[TIPC_NLA_LINK],
2320                                tipc_nl_link_policy);
2321         if (err)
2322                 return err;
2323
2324         if (!attrs[TIPC_NLA_LINK_NAME])
2325                 return -EINVAL;
2326
2327         link_name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
2328
2329         if (strcmp(link_name, tipc_bclink_name) == 0) {
2330                 err = tipc_bclink_reset_stats(net);
2331                 if (err)
2332                         return err;
2333                 return 0;
2334         }
2335
2336         node = tipc_link_find_owner(net, link_name, &bearer_id);
2337         if (!node)
2338                 return -EINVAL;
2339
2340         tipc_node_lock(node);
2341
2342         link = node->links[bearer_id];
2343         if (!link) {
2344                 tipc_node_unlock(node);
2345                 return -EINVAL;
2346         }
2347
2348         link_reset_statistics(link);
2349
2350         tipc_node_unlock(node);
2351
2352         return 0;
2353 }