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