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