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                 return tipc_sk_rcv(net, list);
 850
 851         __skb_queue_purge(list);
 852         return rc;
 853 }
 854
 855 /*
 856  * tipc_link_sync_xmit - synchronize broadcast link endpoints.
 857  *
 858  * Give a newly added peer node the sequence number where it should
 859  * start receiving and acking broadcast packets.
 860  *
 861  * Called with node locked
 862  */
 863 static void tipc_link_sync_xmit(struct tipc_link *link)
 864 {
 865         struct sk_buff *skb;
 866         struct tipc_msg *msg;
 867
 868         skb = tipc_buf_acquire(INT_H_SIZE);
 869         if (!skb)
 870                 return;
 871
 872         msg = buf_msg(skb);
 873         tipc_msg_init(link_own_addr(link), msg, BCAST_PROTOCOL, STATE_MSG,
 874                       INT_H_SIZE, link->addr);
 875         msg_set_last_bcast(msg, link->owner->bclink.acked);
 876         __tipc_link_xmit_skb(link, skb);
 877 }
 878
 879 /*
 880  * tipc_link_sync_rcv - synchronize broadcast link endpoints.
 881  * Receive the sequence number where we should start receiving and
 882  * acking broadcast packets from a newly added peer node, and open
 883  * up for reception of such packets.
 884  *
 885  * Called with node locked
 886  */
 887 static void tipc_link_sync_rcv(struct tipc_node *n, struct sk_buff *buf)
 888 {
 889         struct tipc_msg *msg = buf_msg(buf);
 890
 891         n->bclink.last_sent = n->bclink.last_in = msg_last_bcast(msg);
 892         n->bclink.recv_permitted = true;
 893         kfree_skb(buf);
 894 }
 895
 896 /*
 897  * tipc_link_push_packets - push unsent packets to bearer
 898  *
 899  * Push out the unsent messages of a link where congestion
 900  * has abated. Node is locked.
 901  *
 902  * Called with node locked
 903  */
 904 void tipc_link_push_packets(struct tipc_link *link)
 905 {
 906         struct sk_buff *skb;
 907         struct tipc_msg *msg;
 908         unsigned int ack = mod(link->next_in_no - 1);
 909
 910         while (skb_queue_len(&link->transmq) < link->window) {
 911                 skb = __skb_dequeue(&link->backlogq);
 912                 if (!skb)
 913                         break;
 914                 msg = buf_msg(skb);
 915                 msg_set_ack(msg, ack);
 916                 msg_set_bcast_ack(msg, link->owner->bclink.last_in);
 917                 link->rcv_unacked = 0;
 918                 __skb_queue_tail(&link->transmq, skb);
 919                 tipc_bearer_send(link->owner->net, link->bearer_id,
 920                                  skb, &link->media_addr);
 921         }
 922 }
 923
 924 void tipc_link_reset_all(struct tipc_node *node)
 925 {
 926         char addr_string[16];
 927         u32 i;
 928
 929         tipc_node_lock(node);
 930
 931         pr_warn("Resetting all links to %s\n",
 932                 tipc_addr_string_fill(addr_string, node->addr));
 933
 934         for (i = 0; i < MAX_BEARERS; i++) {
 935                 if (node->links[i]) {
 936                         link_print(node->links[i], "Resetting link\n");
 937                         tipc_link_reset(node->links[i]);
 938                 }
 939         }
 940
 941         tipc_node_unlock(node);
 942 }
 943
 944 static void link_retransmit_failure(struct tipc_link *l_ptr,
 945                                     struct sk_buff *buf)
 946 {
 947         struct tipc_msg *msg = buf_msg(buf);
 948         struct net *net = l_ptr->owner->net;
 949
 950         pr_warn("Retransmission failure on link <%s>\n", l_ptr->name);
 951
 952         if (l_ptr->addr) {
 953                 /* Handle failure on standard link */
 954                 link_print(l_ptr, "Resetting link\n");
 955                 tipc_link_reset(l_ptr);
 956
 957         } else {
 958                 /* Handle failure on broadcast link */
 959                 struct tipc_node *n_ptr;
 960                 char addr_string[16];
 961
 962                 pr_info("Msg seq number: %u,  ", msg_seqno(msg));
 963                 pr_cont("Outstanding acks: %lu\n",
 964                         (unsigned long) TIPC_SKB_CB(buf)->handle);
 965
 966                 n_ptr = tipc_bclink_retransmit_to(net);
 967                 tipc_node_lock(n_ptr);
 968
 969                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 970                 pr_info("Broadcast link info for %s\n", addr_string);
 971                 pr_info("Reception permitted: %d,  Acked: %u\n",
 972                         n_ptr->bclink.recv_permitted,
 973                         n_ptr->bclink.acked);
 974                 pr_info("Last in: %u,  Oos state: %u,  Last sent: %u\n",
 975                         n_ptr->bclink.last_in,
 976                         n_ptr->bclink.oos_state,
 977                         n_ptr->bclink.last_sent);
 978
 979                 tipc_node_unlock(n_ptr);
 980
 981                 tipc_bclink_set_flags(net, TIPC_BCLINK_RESET);
 982                 l_ptr->stale_count = 0;
 983         }
 984 }
 985
 986 void tipc_link_retransmit(struct tipc_link *l_ptr, struct sk_buff *skb,
 987                           u32 retransmits)
 988 {
 989         struct tipc_msg *msg;
 990
 991         if (!skb)
 992                 return;
 993
 994         msg = buf_msg(skb);
 995
 996         /* Detect repeated retransmit failures */
 997         if (l_ptr->last_retransmitted == msg_seqno(msg)) {
 998                 if (++l_ptr->stale_count > 100) {
 999                         link_retransmit_failure(l_ptr, skb);
1000                         return;
1001                 }
1002         } else {
1003                 l_ptr->last_retransmitted = msg_seqno(msg);
1004                 l_ptr->stale_count = 1;
1005         }
1006
1007         skb_queue_walk_from(&l_ptr->transmq, skb) {
1008                 if (!retransmits)
1009                         break;
1010                 msg = buf_msg(skb);
1011                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1012                 msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1013                 tipc_bearer_send(l_ptr->owner->net, l_ptr->bearer_id, skb,
1014                                  &l_ptr->media_addr);
1015                 retransmits--;
1016                 l_ptr->stats.retransmitted++;
1017         }
1018 }
1019
1020 static void link_retrieve_defq(struct tipc_link *link,
1021                                struct sk_buff_head *list)
1022 {
1023         u32 seq_no;
1024
1025         if (skb_queue_empty(&link->deferdq))
1026                 return;
1027
1028         seq_no = buf_seqno(skb_peek(&link->deferdq));
1029         if (seq_no == mod(link->next_in_no))
1030                 skb_queue_splice_tail_init(&link->deferdq, list);
1031 }
1032
1033 /**
1034  * tipc_rcv - process TIPC packets/messages arriving from off-node
1035  * @net: the applicable net namespace
1036  * @skb: TIPC packet
1037  * @b_ptr: pointer to bearer message arrived on
1038  *
1039  * Invoked with no locks held.  Bearer pointer must point to a valid bearer
1040  * structure (i.e. cannot be NULL), but bearer can be inactive.
1041  */
1042 void tipc_rcv(struct net *net, struct sk_buff *skb, struct tipc_bearer *b_ptr)
1043 {
1044         struct tipc_net *tn = net_generic(net, tipc_net_id);
1045         struct sk_buff_head head;
1046         struct tipc_node *n_ptr;
1047         struct tipc_link *l_ptr;
1048         struct sk_buff *skb1, *tmp;
1049         struct tipc_msg *msg;
1050         u32 seq_no;
1051         u32 ackd;
1052         u32 released;
1053
1054         skb2list(skb, &head);
1055
1056         while ((skb = __skb_dequeue(&head))) {
1057                 /* Ensure message is well-formed */
1058                 if (unlikely(!tipc_msg_validate(skb)))
1059                         goto discard;
1060
1061                 /* Handle arrival of a non-unicast link message */
1062                 msg = buf_msg(skb);
1063                 if (unlikely(msg_non_seq(msg))) {
1064                         if (msg_user(msg) ==  LINK_CONFIG)
1065                                 tipc_disc_rcv(net, skb, b_ptr);
1066                         else
1067                                 tipc_bclink_rcv(net, skb);
1068                         continue;
1069                 }
1070
1071                 /* Discard unicast link messages destined for another node */
1072                 if (unlikely(!msg_short(msg) &&
1073                              (msg_destnode(msg) != tn->own_addr)))
1074                         goto discard;
1075
1076                 /* Locate neighboring node that sent message */
1077                 n_ptr = tipc_node_find(net, msg_prevnode(msg));
1078                 if (unlikely(!n_ptr))
1079                         goto discard;
1080                 tipc_node_lock(n_ptr);
1081
1082                 /* Locate unicast link endpoint that should handle message */
1083                 l_ptr = n_ptr->links[b_ptr->identity];
1084                 if (unlikely(!l_ptr))
1085                         goto unlock;
1086
1087                 /* Verify that communication with node is currently allowed */
1088                 if ((n_ptr->action_flags & TIPC_WAIT_PEER_LINKS_DOWN) &&
1089                     msg_user(msg) == LINK_PROTOCOL &&
1090                     (msg_type(msg) == RESET_MSG ||
1091                     msg_type(msg) == ACTIVATE_MSG) &&
1092                     !msg_redundant_link(msg))
1093                         n_ptr->action_flags &= ~TIPC_WAIT_PEER_LINKS_DOWN;
1094
1095                 if (tipc_node_blocked(n_ptr))
1096                         goto unlock;
1097
1098                 /* Validate message sequence number info */
1099                 seq_no = msg_seqno(msg);
1100                 ackd = msg_ack(msg);
1101
1102                 /* Release acked messages */
1103                 if (unlikely(n_ptr->bclink.acked != msg_bcast_ack(msg)))
1104                         tipc_bclink_acknowledge(n_ptr, msg_bcast_ack(msg));
1105
1106                 released = 0;
1107                 skb_queue_walk_safe(&l_ptr->transmq, skb1, tmp) {
1108                         if (more(buf_seqno(skb1), ackd))
1109                                 break;
1110                          __skb_unlink(skb1, &l_ptr->transmq);
1111                          kfree_skb(skb1);
1112                          released = 1;
1113                 }
1114
1115                 /* Try sending any messages link endpoint has pending */
1116                 if (unlikely(skb_queue_len(&l_ptr->backlogq)))
1117                         tipc_link_push_packets(l_ptr);
1118
1119                 if (released && !skb_queue_empty(&l_ptr->wakeupq))
1120                         link_prepare_wakeup(l_ptr);
1121
1122                 /* Process the incoming packet */
1123                 if (unlikely(!link_working_working(l_ptr))) {
1124                         if (msg_user(msg) == LINK_PROTOCOL) {
1125                                 tipc_link_proto_rcv(l_ptr, skb);
1126                                 link_retrieve_defq(l_ptr, &head);
1127                                 skb = NULL;
1128                                 goto unlock;
1129                         }
1130
1131                         /* Traffic message. Conditionally activate link */
1132                         link_state_event(l_ptr, TRAFFIC_MSG_EVT);
1133
1134                         if (link_working_working(l_ptr)) {
1135                                 /* Re-insert buffer in front of queue */
1136                                 __skb_queue_head(&head, skb);
1137                                 skb = NULL;
1138                                 goto unlock;
1139                         }
1140                         goto unlock;
1141                 }
1142
1143                 /* Link is now in state WORKING_WORKING */
1144                 if (unlikely(seq_no != mod(l_ptr->next_in_no))) {
1145                         link_handle_out_of_seq_msg(l_ptr, skb);
1146                         link_retrieve_defq(l_ptr, &head);
1147                         skb = NULL;
1148                         goto unlock;
1149                 }
1150                 l_ptr->next_in_no++;
1151                 if (unlikely(!skb_queue_empty(&l_ptr->deferdq)))
1152                         link_retrieve_defq(l_ptr, &head);
1153                 if (unlikely(++l_ptr->rcv_unacked >= TIPC_MIN_LINK_WIN)) {
1154                         l_ptr->stats.sent_acks++;
1155                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
1156                 }
1157                 tipc_link_input(l_ptr, skb);
1158                 skb = NULL;
1159 unlock:
1160                 tipc_node_unlock(n_ptr);
1161 discard:
1162                 if (unlikely(skb))
1163                         kfree_skb(skb);
1164         }
1165 }
1166
1167 /* tipc_data_input - deliver data and name distr msgs to upper layer
1168  *
1169  * Consumes buffer if message is of right type
1170  * Node lock must be held
1171  */
1172 static bool tipc_data_input(struct tipc_link *link, struct sk_buff *skb)
1173 {
1174         struct tipc_node *node = link->owner;
1175         struct tipc_msg *msg = buf_msg(skb);
1176         u32 dport = msg_destport(msg);
1177
1178         switch (msg_user(msg)) {
1179         case TIPC_LOW_IMPORTANCE:
1180         case TIPC_MEDIUM_IMPORTANCE:
1181         case TIPC_HIGH_IMPORTANCE:
1182         case TIPC_CRITICAL_IMPORTANCE:
1183         case CONN_MANAGER:
1184                 if (tipc_skb_queue_tail(&link->inputq, skb, dport)) {
1185                         node->inputq = &link->inputq;
1186                         node->action_flags |= TIPC_MSG_EVT;
1187                 }
1188                 return true;
1189         case NAME_DISTRIBUTOR:
1190                 node->bclink.recv_permitted = true;
1191                 node->namedq = &link->namedq;
1192                 skb_queue_tail(&link->namedq, skb);
1193                 if (skb_queue_len(&link->namedq) == 1)
1194                         node->action_flags |= TIPC_NAMED_MSG_EVT;
1195                 return true;
1196         case MSG_BUNDLER:
1197         case CHANGEOVER_PROTOCOL:
1198         case MSG_FRAGMENTER:
1199         case BCAST_PROTOCOL:
1200                 return false;
1201         default:
1202                 pr_warn("Dropping received illegal msg type\n");
1203                 kfree_skb(skb);
1204                 return false;
1205         };
1206 }
1207
1208 /* tipc_link_input - process packet that has passed link protocol check
1209  *
1210  * Consumes buffer
1211  * Node lock must be held
1212  */
1213 static void tipc_link_input(struct tipc_link *link, struct sk_buff *skb)
1214 {
1215         struct tipc_node *node = link->owner;
1216         struct tipc_msg *msg = buf_msg(skb);
1217         struct sk_buff *iskb;
1218         int pos = 0;
1219
1220         if (likely(tipc_data_input(link, skb)))
1221                 return;
1222
1223         switch (msg_user(msg)) {
1224         case CHANGEOVER_PROTOCOL:
1225                 if (!tipc_link_tunnel_rcv(node, &skb))
1226                         break;
1227                 if (msg_user(buf_msg(skb)) != MSG_BUNDLER) {
1228                         tipc_data_input(link, skb);
1229                         break;
1230                 }
1231         case MSG_BUNDLER:
1232                 link->stats.recv_bundles++;
1233                 link->stats.recv_bundled += msg_msgcnt(msg);
1234
1235                 while (tipc_msg_extract(skb, &iskb, &pos))
1236                         tipc_data_input(link, iskb);
1237                 break;
1238         case MSG_FRAGMENTER:
1239                 link->stats.recv_fragments++;
1240                 if (tipc_buf_append(&link->reasm_buf, &skb)) {
1241                         link->stats.recv_fragmented++;
1242                         tipc_data_input(link, skb);
1243                 } else if (!link->reasm_buf) {
1244                         tipc_link_reset(link);
1245                 }
1246                 break;
1247         case BCAST_PROTOCOL:
1248                 tipc_link_sync_rcv(node, skb);
1249                 break;
1250         default:
1251                 break;
1252         };
1253 }
1254
1255 /**
1256  * tipc_link_defer_pkt - Add out-of-sequence message to deferred reception queue
1257  *
1258  * Returns increase in queue length (i.e. 0 or 1)
1259  */
1260 u32 tipc_link_defer_pkt(struct sk_buff_head *list, struct sk_buff *skb)
1261 {
1262         struct sk_buff *skb1;
1263         u32 seq_no = buf_seqno(skb);
1264
1265         /* Empty queue ? */
1266         if (skb_queue_empty(list)) {
1267                 __skb_queue_tail(list, skb);
1268                 return 1;
1269         }
1270
1271         /* Last ? */
1272         if (less(buf_seqno(skb_peek_tail(list)), seq_no)) {
1273                 __skb_queue_tail(list, skb);
1274                 return 1;
1275         }
1276
1277         /* Locate insertion point in queue, then insert; discard if duplicate */
1278         skb_queue_walk(list, skb1) {
1279                 u32 curr_seqno = buf_seqno(skb1);
1280
1281                 if (seq_no == curr_seqno) {
1282                         kfree_skb(skb);
1283                         return 0;
1284                 }
1285
1286                 if (less(seq_no, curr_seqno))
1287                         break;
1288         }
1289
1290         __skb_queue_before(list, skb1, skb);
1291         return 1;
1292 }
1293
1294 /*
1295  * link_handle_out_of_seq_msg - handle arrival of out-of-sequence packet
1296  */
1297 static void link_handle_out_of_seq_msg(struct tipc_link *l_ptr,
1298                                        struct sk_buff *buf)
1299 {
1300         u32 seq_no = buf_seqno(buf);
1301
1302         if (likely(msg_user(buf_msg(buf)) == LINK_PROTOCOL)) {
1303                 tipc_link_proto_rcv(l_ptr, buf);
1304                 return;
1305         }
1306
1307         /* Record OOS packet arrival (force mismatch on next timeout) */
1308         l_ptr->checkpoint--;
1309
1310         /*
1311          * Discard packet if a duplicate; otherwise add it to deferred queue
1312          * and notify peer of gap as per protocol specification
1313          */
1314         if (less(seq_no, mod(l_ptr->next_in_no))) {
1315                 l_ptr->stats.duplicates++;
1316                 kfree_skb(buf);
1317                 return;
1318         }
1319
1320         if (tipc_link_defer_pkt(&l_ptr->deferdq, buf)) {
1321                 l_ptr->stats.deferred_recv++;
1322                 if ((skb_queue_len(&l_ptr->deferdq) % TIPC_MIN_LINK_WIN) == 1)
1323                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
1324         } else {
1325                 l_ptr->stats.duplicates++;
1326         }
1327 }
1328
1329 /*
1330  * Send protocol message to the other endpoint.
1331  */
1332 void tipc_link_proto_xmit(struct tipc_link *l_ptr, u32 msg_typ, int probe_msg,
1333                           u32 gap, u32 tolerance, u32 priority, u32 ack_mtu)
1334 {
1335         struct sk_buff *buf = NULL;
1336         struct tipc_msg *msg = l_ptr->pmsg;
1337         u32 msg_size = sizeof(l_ptr->proto_msg);
1338         int r_flag;
1339
1340         /* Don't send protocol message during link changeover */
1341         if (l_ptr->exp_msg_count)
1342                 return;
1343
1344         /* Abort non-RESET send if communication with node is prohibited */
1345         if ((tipc_node_blocked(l_ptr->owner)) && (msg_typ != RESET_MSG))
1346                 return;
1347
1348         /* Create protocol message with "out-of-sequence" sequence number */
1349         msg_set_type(msg, msg_typ);
1350         msg_set_net_plane(msg, l_ptr->net_plane);
1351         msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1352         msg_set_last_bcast(msg, tipc_bclink_get_last_sent(l_ptr->owner->net));
1353
1354         if (msg_typ == STATE_MSG) {
1355                 u32 next_sent = mod(l_ptr->next_out_no);
1356
1357                 if (!tipc_link_is_up(l_ptr))
1358                         return;
1359                 if (skb_queue_len(&l_ptr->backlogq))
1360                         next_sent = buf_seqno(skb_peek(&l_ptr->backlogq));
1361                 msg_set_next_sent(msg, next_sent);
1362                 if (!skb_queue_empty(&l_ptr->deferdq)) {
1363                         u32 rec = buf_seqno(skb_peek(&l_ptr->deferdq));
1364                         gap = mod(rec - mod(l_ptr->next_in_no));
1365                 }
1366                 msg_set_seq_gap(msg, gap);
1367                 if (gap)
1368                         l_ptr->stats.sent_nacks++;
1369                 msg_set_link_tolerance(msg, tolerance);
1370                 msg_set_linkprio(msg, priority);
1371                 msg_set_max_pkt(msg, ack_mtu);
1372                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1373                 msg_set_probe(msg, probe_msg != 0);
1374                 if (probe_msg) {
1375                         u32 mtu = l_ptr->max_pkt;
1376
1377                         if ((mtu < l_ptr->max_pkt_target) &&
1378                             link_working_working(l_ptr) &&
1379                             l_ptr->fsm_msg_cnt) {
1380                                 msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
1381                                 if (l_ptr->max_pkt_probes == 10) {
1382                                         l_ptr->max_pkt_target = (msg_size - 4);
1383                                         l_ptr->max_pkt_probes = 0;
1384                                         msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
1385                                 }
1386                                 l_ptr->max_pkt_probes++;
1387                         }
1388
1389                         l_ptr->stats.sent_probes++;
1390                 }
1391                 l_ptr->stats.sent_states++;
1392         } else {                /* RESET_MSG or ACTIVATE_MSG */
1393                 msg_set_ack(msg, mod(l_ptr->reset_checkpoint - 1));
1394                 msg_set_seq_gap(msg, 0);
1395                 msg_set_next_sent(msg, 1);
1396                 msg_set_probe(msg, 0);
1397                 msg_set_link_tolerance(msg, l_ptr->tolerance);
1398                 msg_set_linkprio(msg, l_ptr->priority);
1399                 msg_set_max_pkt(msg, l_ptr->max_pkt_target);
1400         }
1401
1402         r_flag = (l_ptr->owner->working_links > tipc_link_is_up(l_ptr));
1403         msg_set_redundant_link(msg, r_flag);
1404         msg_set_linkprio(msg, l_ptr->priority);
1405         msg_set_size(msg, msg_size);
1406
1407         msg_set_seqno(msg, mod(l_ptr->next_out_no + (0xffff/2)));
1408
1409         buf = tipc_buf_acquire(msg_size);
1410         if (!buf)
1411                 return;
1412
1413         skb_copy_to_linear_data(buf, msg, sizeof(l_ptr->proto_msg));
1414         buf->priority = TC_PRIO_CONTROL;
1415         tipc_bearer_send(l_ptr->owner->net, l_ptr->bearer_id, buf,
1416                          &l_ptr->media_addr);
1417         l_ptr->rcv_unacked = 0;
1418         kfree_skb(buf);
1419 }
1420
1421 /*
1422  * Receive protocol message :
1423  * Note that network plane id propagates through the network, and may
1424  * change at any time. The node with lowest address rules
1425  */
1426 static void tipc_link_proto_rcv(struct tipc_link *l_ptr,
1427                                 struct sk_buff *buf)
1428 {
1429         u32 rec_gap = 0;
1430         u32 max_pkt_info;
1431         u32 max_pkt_ack;
1432         u32 msg_tol;
1433         struct tipc_msg *msg = buf_msg(buf);
1434
1435         /* Discard protocol message during link changeover */
1436         if (l_ptr->exp_msg_count)
1437                 goto exit;
1438
1439         if (l_ptr->net_plane != msg_net_plane(msg))
1440                 if (link_own_addr(l_ptr) > msg_prevnode(msg))
1441                         l_ptr->net_plane = msg_net_plane(msg);
1442
1443         switch (msg_type(msg)) {
1444
1445         case RESET_MSG:
1446                 if (!link_working_unknown(l_ptr) &&
1447                     (l_ptr->peer_session != INVALID_SESSION)) {
1448                         if (less_eq(msg_session(msg), l_ptr->peer_session))
1449                                 break; /* duplicate or old reset: ignore */
1450                 }
1451
1452                 if (!msg_redundant_link(msg) && (link_working_working(l_ptr) ||
1453                                 link_working_unknown(l_ptr))) {
1454                         /*
1455                          * peer has lost contact -- don't allow peer's links
1456                          * to reactivate before we recognize loss & clean up
1457                          */
1458                         l_ptr->owner->action_flags |= TIPC_WAIT_OWN_LINKS_DOWN;
1459                 }
1460
1461                 link_state_event(l_ptr, RESET_MSG);
1462
1463                 /* fall thru' */
1464         case ACTIVATE_MSG:
1465                 /* Update link settings according other endpoint's values */
1466                 strcpy((strrchr(l_ptr->name, ':') + 1), (char *)msg_data(msg));
1467
1468                 msg_tol = msg_link_tolerance(msg);
1469                 if (msg_tol > l_ptr->tolerance)
1470                         link_set_supervision_props(l_ptr, msg_tol);
1471
1472                 if (msg_linkprio(msg) > l_ptr->priority)
1473                         l_ptr->priority = msg_linkprio(msg);
1474
1475                 max_pkt_info = msg_max_pkt(msg);
1476                 if (max_pkt_info) {
1477                         if (max_pkt_info < l_ptr->max_pkt_target)
1478                                 l_ptr->max_pkt_target = max_pkt_info;
1479                         if (l_ptr->max_pkt > l_ptr->max_pkt_target)
1480                                 l_ptr->max_pkt = l_ptr->max_pkt_target;
1481                 } else {
1482                         l_ptr->max_pkt = l_ptr->max_pkt_target;
1483                 }
1484
1485                 /* Synchronize broadcast link info, if not done previously */
1486                 if (!tipc_node_is_up(l_ptr->owner)) {
1487                         l_ptr->owner->bclink.last_sent =
1488                                 l_ptr->owner->bclink.last_in =
1489                                 msg_last_bcast(msg);
1490                         l_ptr->owner->bclink.oos_state = 0;
1491                 }
1492
1493                 l_ptr->peer_session = msg_session(msg);
1494                 l_ptr->peer_bearer_id = msg_bearer_id(msg);
1495
1496                 if (msg_type(msg) == ACTIVATE_MSG)
1497                         link_state_event(l_ptr, ACTIVATE_MSG);
1498                 break;
1499         case STATE_MSG:
1500
1501                 msg_tol = msg_link_tolerance(msg);
1502                 if (msg_tol)
1503                         link_set_supervision_props(l_ptr, msg_tol);
1504
1505                 if (msg_linkprio(msg) &&
1506                     (msg_linkprio(msg) != l_ptr->priority)) {
1507                         pr_debug("%s<%s>, priority change %u->%u\n",
1508                                  link_rst_msg, l_ptr->name,
1509                                  l_ptr->priority, msg_linkprio(msg));
1510                         l_ptr->priority = msg_linkprio(msg);
1511                         tipc_link_reset(l_ptr); /* Enforce change to take effect */
1512                         break;
1513                 }
1514
1515                 /* Record reception; force mismatch at next timeout: */
1516                 l_ptr->checkpoint--;
1517
1518                 link_state_event(l_ptr, TRAFFIC_MSG_EVT);
1519                 l_ptr->stats.recv_states++;
1520                 if (link_reset_unknown(l_ptr))
1521                         break;
1522
1523                 if (less_eq(mod(l_ptr->next_in_no), msg_next_sent(msg))) {
1524                         rec_gap = mod(msg_next_sent(msg) -
1525                                       mod(l_ptr->next_in_no));
1526                 }
1527
1528                 max_pkt_ack = msg_max_pkt(msg);
1529                 if (max_pkt_ack > l_ptr->max_pkt) {
1530                         l_ptr->max_pkt = max_pkt_ack;
1531                         l_ptr->max_pkt_probes = 0;
1532                 }
1533
1534                 max_pkt_ack = 0;
1535                 if (msg_probe(msg)) {
1536                         l_ptr->stats.recv_probes++;
1537                         if (msg_size(msg) > sizeof(l_ptr->proto_msg))
1538                                 max_pkt_ack = msg_size(msg);
1539                 }
1540
1541                 /* Protocol message before retransmits, reduce loss risk */
1542                 if (l_ptr->owner->bclink.recv_permitted)
1543                         tipc_bclink_update_link_state(l_ptr->owner,
1544                                                       msg_last_bcast(msg));
1545
1546                 if (rec_gap || (msg_probe(msg))) {
1547                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, rec_gap, 0,
1548                                              0, max_pkt_ack);
1549                 }
1550                 if (msg_seq_gap(msg)) {
1551                         l_ptr->stats.recv_nacks++;
1552                         tipc_link_retransmit(l_ptr, skb_peek(&l_ptr->transmq),
1553                                              msg_seq_gap(msg));
1554                 }
1555                 break;
1556         }
1557 exit:
1558         kfree_skb(buf);
1559 }
1560
1561
1562 /* tipc_link_tunnel_xmit(): Tunnel one packet via a link belonging to
1563  * a different bearer. Owner node is locked.
1564  */
1565 static void tipc_link_tunnel_xmit(struct tipc_link *l_ptr,
1566                                   struct tipc_msg *tunnel_hdr,
1567                                   struct tipc_msg *msg,
1568                                   u32 selector)
1569 {
1570         struct tipc_link *tunnel;
1571         struct sk_buff *skb;
1572         u32 length = msg_size(msg);
1573
1574         tunnel = l_ptr->owner->active_links[selector & 1];
1575         if (!tipc_link_is_up(tunnel)) {
1576                 pr_warn("%stunnel link no longer available\n", link_co_err);
1577                 return;
1578         }
1579         msg_set_size(tunnel_hdr, length + INT_H_SIZE);
1580         skb = tipc_buf_acquire(length + INT_H_SIZE);
1581         if (!skb) {
1582                 pr_warn("%sunable to send tunnel msg\n", link_co_err);
1583                 return;
1584         }
1585         skb_copy_to_linear_data(skb, tunnel_hdr, INT_H_SIZE);
1586         skb_copy_to_linear_data_offset(skb, INT_H_SIZE, msg, length);
1587         __tipc_link_xmit_skb(tunnel, skb);
1588 }
1589
1590
1591 /* tipc_link_failover_send_queue(): A link has gone down, but a second
1592  * link is still active. We can do failover. Tunnel the failing link's
1593  * whole send queue via the remaining link. This way, we don't lose
1594  * any packets, and sequence order is preserved for subsequent traffic
1595  * sent over the remaining link. Owner node is locked.
1596  */
1597 void tipc_link_failover_send_queue(struct tipc_link *l_ptr)
1598 {
1599         int msgcount;
1600         struct tipc_link *tunnel = l_ptr->owner->active_links[0];
1601         struct tipc_msg tunnel_hdr;
1602         struct sk_buff *skb;
1603         int split_bundles;
1604
1605         if (!tunnel)
1606                 return;
1607
1608         tipc_msg_init(link_own_addr(l_ptr), &tunnel_hdr, CHANGEOVER_PROTOCOL,
1609                       ORIGINAL_MSG, INT_H_SIZE, l_ptr->addr);
1610         skb_queue_splice_tail_init(&l_ptr->backlogq, &l_ptr->transmq);
1611         msgcount = skb_queue_len(&l_ptr->transmq);
1612         msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
1613         msg_set_msgcnt(&tunnel_hdr, msgcount);
1614
1615         if (skb_queue_empty(&l_ptr->transmq)) {
1616                 skb = tipc_buf_acquire(INT_H_SIZE);
1617                 if (skb) {
1618                         skb_copy_to_linear_data(skb, &tunnel_hdr, INT_H_SIZE);
1619                         msg_set_size(&tunnel_hdr, INT_H_SIZE);
1620                         __tipc_link_xmit_skb(tunnel, skb);
1621                 } else {
1622                         pr_warn("%sunable to send changeover msg\n",
1623                                 link_co_err);
1624                 }
1625                 return;
1626         }
1627
1628         split_bundles = (l_ptr->owner->active_links[0] !=
1629                          l_ptr->owner->active_links[1]);
1630
1631         skb_queue_walk(&l_ptr->transmq, skb) {
1632                 struct tipc_msg *msg = buf_msg(skb);
1633
1634                 if ((msg_user(msg) == MSG_BUNDLER) && split_bundles) {
1635                         struct tipc_msg *m = msg_get_wrapped(msg);
1636                         unchar *pos = (unchar *)m;
1637
1638                         msgcount = msg_msgcnt(msg);
1639                         while (msgcount--) {
1640                                 msg_set_seqno(m, msg_seqno(msg));
1641                                 tipc_link_tunnel_xmit(l_ptr, &tunnel_hdr, m,
1642                                                       msg_link_selector(m));
1643                                 pos += align(msg_size(m));
1644                                 m = (struct tipc_msg *)pos;
1645                         }
1646                 } else {
1647                         tipc_link_tunnel_xmit(l_ptr, &tunnel_hdr, msg,
1648                                               msg_link_selector(msg));
1649                 }
1650         }
1651 }
1652
1653 /* tipc_link_dup_queue_xmit(): A second link has become active. Tunnel a
1654  * duplicate of the first link's send queue via the new link. This way, we
1655  * are guaranteed that currently queued packets from a socket are delivered
1656  * before future traffic from the same socket, even if this is using the
1657  * new link. The last arriving copy of each duplicate packet is dropped at
1658  * the receiving end by the regular protocol check, so packet cardinality
1659  * and sequence order is preserved per sender/receiver socket pair.
1660  * Owner node is locked.
1661  */
1662 void tipc_link_dup_queue_xmit(struct tipc_link *link,
1663                               struct tipc_link *tnl)
1664 {
1665         struct sk_buff *skb;
1666         struct tipc_msg tnl_hdr;
1667         struct sk_buff_head *queue = &link->transmq;
1668         int mcnt;
1669
1670         tipc_msg_init(link_own_addr(link), &tnl_hdr, CHANGEOVER_PROTOCOL,
1671                       DUPLICATE_MSG, INT_H_SIZE, link->addr);
1672         mcnt = skb_queue_len(&link->transmq) + skb_queue_len(&link->backlogq);
1673         msg_set_msgcnt(&tnl_hdr, mcnt);
1674         msg_set_bearer_id(&tnl_hdr, link->peer_bearer_id);
1675
1676 tunnel_queue:
1677         skb_queue_walk(queue, skb) {
1678                 struct sk_buff *outskb;
1679                 struct tipc_msg *msg = buf_msg(skb);
1680                 u32 len = msg_size(msg);
1681
1682                 msg_set_ack(msg, mod(link->next_in_no - 1));
1683                 msg_set_bcast_ack(msg, link->owner->bclink.last_in);
1684                 msg_set_size(&tnl_hdr, len + INT_H_SIZE);
1685                 outskb = tipc_buf_acquire(len + INT_H_SIZE);
1686                 if (outskb == NULL) {
1687                         pr_warn("%sunable to send duplicate msg\n",
1688                                 link_co_err);
1689                         return;
1690                 }
1691                 skb_copy_to_linear_data(outskb, &tnl_hdr, INT_H_SIZE);
1692                 skb_copy_to_linear_data_offset(outskb, INT_H_SIZE,
1693                                                skb->data, len);
1694                 __tipc_link_xmit_skb(tnl, outskb);
1695                 if (!tipc_link_is_up(link))
1696                         return;
1697         }
1698         if (queue == &link->backlogq)
1699                 return;
1700         queue = &link->backlogq;
1701         goto tunnel_queue;
1702 }
1703
1704 /* tipc_link_dup_rcv(): Receive a tunnelled DUPLICATE_MSG packet.
1705  * Owner node is locked.
1706  */
1707 static void tipc_link_dup_rcv(struct tipc_link *link,
1708                               struct sk_buff *skb)
1709 {
1710         struct sk_buff *iskb;
1711         int pos = 0;
1712
1713         if (!tipc_link_is_up(link))
1714                 return;
1715
1716         if (!tipc_msg_extract(skb, &iskb, &pos)) {
1717                 pr_warn("%sfailed to extract inner dup pkt\n", link_co_err);
1718                 return;
1719         }
1720         /* Append buffer to deferred queue, if applicable: */
1721         link_handle_out_of_seq_msg(link, iskb);
1722 }
1723
1724 /*  tipc_link_failover_rcv(): Receive a tunnelled ORIGINAL_MSG packet
1725  *  Owner node is locked.
1726  */
1727 static struct sk_buff *tipc_link_failover_rcv(struct tipc_link *l_ptr,
1728                                               struct sk_buff *t_buf)
1729 {
1730         struct tipc_msg *t_msg = buf_msg(t_buf);
1731         struct sk_buff *buf = NULL;
1732         struct tipc_msg *msg;
1733         int pos = 0;
1734
1735         if (tipc_link_is_up(l_ptr))
1736                 tipc_link_reset(l_ptr);
1737
1738         /* First failover packet? */
1739         if (l_ptr->exp_msg_count == START_CHANGEOVER)
1740                 l_ptr->exp_msg_count = msg_msgcnt(t_msg);
1741
1742         /* Should there be an inner packet? */
1743         if (l_ptr->exp_msg_count) {
1744                 l_ptr->exp_msg_count--;
1745                 if (!tipc_msg_extract(t_buf, &buf, &pos)) {
1746                         pr_warn("%sno inner failover pkt\n", link_co_err);
1747                         goto exit;
1748                 }
1749                 msg = buf_msg(buf);
1750
1751                 if (less(msg_seqno(msg), l_ptr->reset_checkpoint)) {
1752                         kfree_skb(buf);
1753                         buf = NULL;
1754                         goto exit;
1755                 }
1756                 if (msg_user(msg) == MSG_FRAGMENTER) {
1757                         l_ptr->stats.recv_fragments++;
1758                         tipc_buf_append(&l_ptr->reasm_buf, &buf);
1759                 }
1760         }
1761 exit:
1762         if ((!l_ptr->exp_msg_count) && (l_ptr->flags & LINK_STOPPED))
1763                 tipc_link_delete(l_ptr);
1764         return buf;
1765 }
1766
1767 /*  tipc_link_tunnel_rcv(): Receive a tunnelled packet, sent
1768  *  via other link as result of a failover (ORIGINAL_MSG) or
1769  *  a new active link (DUPLICATE_MSG). Failover packets are
1770  *  returned to the active link for delivery upwards.
1771  *  Owner node is locked.
1772  */
1773 static int tipc_link_tunnel_rcv(struct tipc_node *n_ptr,
1774                                 struct sk_buff **buf)
1775 {
1776         struct sk_buff *t_buf = *buf;
1777         struct tipc_link *l_ptr;
1778         struct tipc_msg *t_msg = buf_msg(t_buf);
1779         u32 bearer_id = msg_bearer_id(t_msg);
1780
1781         *buf = NULL;
1782
1783         if (bearer_id >= MAX_BEARERS)
1784                 goto exit;
1785
1786         l_ptr = n_ptr->links[bearer_id];
1787         if (!l_ptr)
1788                 goto exit;
1789
1790         if (msg_type(t_msg) == DUPLICATE_MSG)
1791                 tipc_link_dup_rcv(l_ptr, t_buf);
1792         else if (msg_type(t_msg) == ORIGINAL_MSG)
1793                 *buf = tipc_link_failover_rcv(l_ptr, t_buf);
1794         else
1795                 pr_warn("%sunknown tunnel pkt received\n", link_co_err);
1796 exit:
1797         kfree_skb(t_buf);
1798         return *buf != NULL;
1799 }
1800
1801 static void link_set_supervision_props(struct tipc_link *l_ptr, u32 tol)
1802 {
1803         unsigned long intv = ((tol / 4) > 500) ? 500 : tol / 4;
1804
1805         if ((tol < TIPC_MIN_LINK_TOL) || (tol > TIPC_MAX_LINK_TOL))
1806                 return;
1807
1808         l_ptr->tolerance = tol;
1809         l_ptr->cont_intv = msecs_to_jiffies(intv);
1810         l_ptr->abort_limit = tol / (jiffies_to_msecs(l_ptr->cont_intv) / 4);
1811 }
1812
1813 void tipc_link_set_queue_limits(struct tipc_link *l, u32 win)
1814 {
1815         int max_bulk = TIPC_MAX_PUBLICATIONS / (l->max_pkt / ITEM_SIZE);
1816
1817         l->window = win;
1818         l->queue_limit[TIPC_LOW_IMPORTANCE]      = win / 2;
1819         l->queue_limit[TIPC_MEDIUM_IMPORTANCE]   = win;
1820         l->queue_limit[TIPC_HIGH_IMPORTANCE]     = win / 2 * 3;
1821         l->queue_limit[TIPC_CRITICAL_IMPORTANCE] = win * 2;
1822         l->queue_limit[TIPC_SYSTEM_IMPORTANCE]   = max_bulk;
1823 }
1824
1825 /* tipc_link_find_owner - locate owner node of link by link's name
1826  * @net: the applicable net namespace
1827  * @name: pointer to link name string
1828  * @bearer_id: pointer to index in 'node->links' array where the link was found.
1829  *
1830  * Returns pointer to node owning the link, or 0 if no matching link is found.
1831  */
1832 static struct tipc_node *tipc_link_find_owner(struct net *net,
1833                                               const char *link_name,
1834                                               unsigned int *bearer_id)
1835 {
1836         struct tipc_net *tn = net_generic(net, tipc_net_id);
1837         struct tipc_link *l_ptr;
1838         struct tipc_node *n_ptr;
1839         struct tipc_node *found_node = NULL;
1840         int i;
1841
1842         *bearer_id = 0;
1843         rcu_read_lock();
1844         list_for_each_entry_rcu(n_ptr, &tn->node_list, list) {
1845                 tipc_node_lock(n_ptr);
1846                 for (i = 0; i < MAX_BEARERS; i++) {
1847                         l_ptr = n_ptr->links[i];
1848                         if (l_ptr && !strcmp(l_ptr->name, link_name)) {
1849                                 *bearer_id = i;
1850                                 found_node = n_ptr;
1851                                 break;
1852                         }
1853                 }
1854                 tipc_node_unlock(n_ptr);
1855                 if (found_node)
1856                         break;
1857         }
1858         rcu_read_unlock();
1859
1860         return found_node;
1861 }
1862
1863 /**
1864  * link_reset_statistics - reset link statistics
1865  * @l_ptr: pointer to link
1866  */
1867 static void link_reset_statistics(struct tipc_link *l_ptr)
1868 {
1869         memset(&l_ptr->stats, 0, sizeof(l_ptr->stats));
1870         l_ptr->stats.sent_info = l_ptr->next_out_no;
1871         l_ptr->stats.recv_info = l_ptr->next_in_no;
1872 }
1873
1874 static void link_print(struct tipc_link *l_ptr, const char *str)
1875 {
1876         struct tipc_net *tn = net_generic(l_ptr->owner->net, tipc_net_id);
1877         struct tipc_bearer *b_ptr;
1878
1879         rcu_read_lock();
1880         b_ptr = rcu_dereference_rtnl(tn->bearer_list[l_ptr->bearer_id]);
1881         if (b_ptr)
1882                 pr_info("%s Link %x<%s>:", str, l_ptr->addr, b_ptr->name);
1883         rcu_read_unlock();
1884
1885         if (link_working_unknown(l_ptr))
1886                 pr_cont(":WU\n");
1887         else if (link_reset_reset(l_ptr))
1888                 pr_cont(":RR\n");
1889         else if (link_reset_unknown(l_ptr))
1890                 pr_cont(":RU\n");
1891         else if (link_working_working(l_ptr))
1892                 pr_cont(":WW\n");
1893         else
1894                 pr_cont("\n");
1895 }
1896
1897 /* Parse and validate nested (link) properties valid for media, bearer and link
1898  */
1899 int tipc_nl_parse_link_prop(struct nlattr *prop, struct nlattr *props[])
1900 {
1901         int err;
1902
1903         err = nla_parse_nested(props, TIPC_NLA_PROP_MAX, prop,
1904                                tipc_nl_prop_policy);
1905         if (err)
1906                 return err;
1907
1908         if (props[TIPC_NLA_PROP_PRIO]) {
1909                 u32 prio;
1910
1911                 prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
1912                 if (prio > TIPC_MAX_LINK_PRI)
1913                         return -EINVAL;
1914         }
1915
1916         if (props[TIPC_NLA_PROP_TOL]) {
1917                 u32 tol;
1918
1919                 tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
1920                 if ((tol < TIPC_MIN_LINK_TOL) || (tol > TIPC_MAX_LINK_TOL))
1921                         return -EINVAL;
1922         }
1923
1924         if (props[TIPC_NLA_PROP_WIN]) {
1925                 u32 win;
1926
1927                 win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
1928                 if ((win < TIPC_MIN_LINK_WIN) || (win > TIPC_MAX_LINK_WIN))
1929                         return -EINVAL;
1930         }
1931
1932         return 0;
1933 }
1934
1935 int tipc_nl_link_set(struct sk_buff *skb, struct genl_info *info)
1936 {
1937         int err;
1938         int res = 0;
1939         int bearer_id;
1940         char *name;
1941         struct tipc_link *link;
1942         struct tipc_node *node;
1943         struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
1944         struct net *net = sock_net(skb->sk);
1945
1946         if (!info->attrs[TIPC_NLA_LINK])
1947                 return -EINVAL;
1948
1949         err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
1950                                info->attrs[TIPC_NLA_LINK],
1951                                tipc_nl_link_policy);
1952         if (err)
1953                 return err;
1954
1955         if (!attrs[TIPC_NLA_LINK_NAME])
1956                 return -EINVAL;
1957
1958         name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
1959
1960         node = tipc_link_find_owner(net, name, &bearer_id);
1961         if (!node)
1962                 return -EINVAL;
1963
1964         tipc_node_lock(node);
1965
1966         link = node->links[bearer_id];
1967         if (!link) {
1968                 res = -EINVAL;
1969                 goto out;
1970         }
1971
1972         if (attrs[TIPC_NLA_LINK_PROP]) {
1973                 struct nlattr *props[TIPC_NLA_PROP_MAX + 1];
1974
1975                 err = tipc_nl_parse_link_prop(attrs[TIPC_NLA_LINK_PROP],
1976                                               props);
1977                 if (err) {
1978                         res = err;
1979                         goto out;
1980                 }
1981
1982                 if (props[TIPC_NLA_PROP_TOL]) {
1983                         u32 tol;
1984
1985                         tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
1986                         link_set_supervision_props(link, tol);
1987                         tipc_link_proto_xmit(link, STATE_MSG, 0, 0, tol, 0, 0);
1988                 }
1989                 if (props[TIPC_NLA_PROP_PRIO]) {
1990                         u32 prio;
1991
1992                         prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
1993                         link->priority = prio;
1994                         tipc_link_proto_xmit(link, STATE_MSG, 0, 0, 0, prio, 0);
1995                 }
1996                 if (props[TIPC_NLA_PROP_WIN]) {
1997                         u32 win;
1998
1999                         win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
2000                         tipc_link_set_queue_limits(link, win);
2001                 }
2002         }
2003
2004 out:
2005         tipc_node_unlock(node);
2006
2007         return res;
2008 }
2009
2010 static int __tipc_nl_add_stats(struct sk_buff *skb, struct tipc_stats *s)
2011 {
2012         int i;
2013         struct nlattr *stats;
2014
2015         struct nla_map {
2016                 u32 key;
2017                 u32 val;
2018         };
2019
2020         struct nla_map map[] = {
2021                 {TIPC_NLA_STATS_RX_INFO, s->recv_info},
2022                 {TIPC_NLA_STATS_RX_FRAGMENTS, s->recv_fragments},
2023                 {TIPC_NLA_STATS_RX_FRAGMENTED, s->recv_fragmented},
2024                 {TIPC_NLA_STATS_RX_BUNDLES, s->recv_bundles},
2025                 {TIPC_NLA_STATS_RX_BUNDLED, s->recv_bundled},
2026                 {TIPC_NLA_STATS_TX_INFO, s->sent_info},
2027                 {TIPC_NLA_STATS_TX_FRAGMENTS, s->sent_fragments},
2028                 {TIPC_NLA_STATS_TX_FRAGMENTED, s->sent_fragmented},
2029                 {TIPC_NLA_STATS_TX_BUNDLES, s->sent_bundles},
2030                 {TIPC_NLA_STATS_TX_BUNDLED, s->sent_bundled},
2031                 {TIPC_NLA_STATS_MSG_PROF_TOT, (s->msg_length_counts) ?
2032                         s->msg_length_counts : 1},
2033                 {TIPC_NLA_STATS_MSG_LEN_CNT, s->msg_length_counts},
2034                 {TIPC_NLA_STATS_MSG_LEN_TOT, s->msg_lengths_total},
2035                 {TIPC_NLA_STATS_MSG_LEN_P0, s->msg_length_profile[0]},
2036                 {TIPC_NLA_STATS_MSG_LEN_P1, s->msg_length_profile[1]},
2037                 {TIPC_NLA_STATS_MSG_LEN_P2, s->msg_length_profile[2]},
2038                 {TIPC_NLA_STATS_MSG_LEN_P3, s->msg_length_profile[3]},
2039                 {TIPC_NLA_STATS_MSG_LEN_P4, s->msg_length_profile[4]},
2040                 {TIPC_NLA_STATS_MSG_LEN_P5, s->msg_length_profile[5]},
2041                 {TIPC_NLA_STATS_MSG_LEN_P6, s->msg_length_profile[6]},
2042                 {TIPC_NLA_STATS_RX_STATES, s->recv_states},
2043                 {TIPC_NLA_STATS_RX_PROBES, s->recv_probes},
2044                 {TIPC_NLA_STATS_RX_NACKS, s->recv_nacks},
2045                 {TIPC_NLA_STATS_RX_DEFERRED, s->deferred_recv},
2046                 {TIPC_NLA_STATS_TX_STATES, s->sent_states},
2047                 {TIPC_NLA_STATS_TX_PROBES, s->sent_probes},
2048                 {TIPC_NLA_STATS_TX_NACKS, s->sent_nacks},
2049                 {TIPC_NLA_STATS_TX_ACKS, s->sent_acks},
2050                 {TIPC_NLA_STATS_RETRANSMITTED, s->retransmitted},
2051                 {TIPC_NLA_STATS_DUPLICATES, s->duplicates},
2052                 {TIPC_NLA_STATS_LINK_CONGS, s->link_congs},
2053                 {TIPC_NLA_STATS_MAX_QUEUE, s->max_queue_sz},
2054                 {TIPC_NLA_STATS_AVG_QUEUE, s->queue_sz_counts ?
2055                         (s->accu_queue_sz / s->queue_sz_counts) : 0}
2056         };
2057
2058         stats = nla_nest_start(skb, TIPC_NLA_LINK_STATS);
2059         if (!stats)
2060                 return -EMSGSIZE;
2061
2062         for (i = 0; i <  ARRAY_SIZE(map); i++)
2063                 if (nla_put_u32(skb, map[i].key, map[i].val))
2064                         goto msg_full;
2065
2066         nla_nest_end(skb, stats);
2067
2068         return 0;
2069 msg_full:
2070         nla_nest_cancel(skb, stats);
2071
2072         return -EMSGSIZE;
2073 }
2074
2075 /* Caller should hold appropriate locks to protect the link */
2076 static int __tipc_nl_add_link(struct net *net, struct tipc_nl_msg *msg,
2077                               struct tipc_link *link)
2078 {
2079         int err;
2080         void *hdr;
2081         struct nlattr *attrs;
2082         struct nlattr *prop;
2083         struct tipc_net *tn = net_generic(net, tipc_net_id);
2084
2085         hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
2086                           NLM_F_MULTI, TIPC_NL_LINK_GET);
2087         if (!hdr)
2088                 return -EMSGSIZE;
2089
2090         attrs = nla_nest_start(msg->skb, TIPC_NLA_LINK);
2091         if (!attrs)
2092                 goto msg_full;
2093
2094         if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, link->name))
2095                 goto attr_msg_full;
2096         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_DEST,
2097                         tipc_cluster_mask(tn->own_addr)))
2098                 goto attr_msg_full;
2099         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_MTU, link->max_pkt))
2100                 goto attr_msg_full;
2101         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, link->next_in_no))
2102                 goto attr_msg_full;
2103         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, link->next_out_no))
2104                 goto attr_msg_full;
2105
2106         if (tipc_link_is_up(link))
2107                 if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
2108                         goto attr_msg_full;
2109         if (tipc_link_is_active(link))
2110                 if (nla_put_flag(msg->skb, TIPC_NLA_LINK_ACTIVE))
2111                         goto attr_msg_full;
2112
2113         prop = nla_nest_start(msg->skb, TIPC_NLA_LINK_PROP);
2114         if (!prop)
2115                 goto attr_msg_full;
2116         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
2117                 goto prop_msg_full;
2118         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_TOL, link->tolerance))
2119                 goto prop_msg_full;
2120         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN,
2121                         link->queue_limit[TIPC_LOW_IMPORTANCE]))
2122                 goto prop_msg_full;
2123         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
2124                 goto prop_msg_full;
2125         nla_nest_end(msg->skb, prop);
2126
2127         err = __tipc_nl_add_stats(msg->skb, &link->stats);
2128         if (err)
2129                 goto attr_msg_full;
2130
2131         nla_nest_end(msg->skb, attrs);
2132         genlmsg_end(msg->skb, hdr);
2133
2134         return 0;
2135
2136 prop_msg_full:
2137         nla_nest_cancel(msg->skb, prop);
2138 attr_msg_full:
2139         nla_nest_cancel(msg->skb, attrs);
2140 msg_full:
2141         genlmsg_cancel(msg->skb, hdr);
2142
2143         return -EMSGSIZE;
2144 }
2145
2146 /* Caller should hold node lock  */
2147 static int __tipc_nl_add_node_links(struct net *net, struct tipc_nl_msg *msg,
2148                                     struct tipc_node *node, u32 *prev_link)
2149 {
2150         u32 i;
2151         int err;
2152
2153         for (i = *prev_link; i < MAX_BEARERS; i++) {
2154                 *prev_link = i;
2155
2156                 if (!node->links[i])
2157                         continue;
2158
2159                 err = __tipc_nl_add_link(net, msg, node->links[i]);
2160                 if (err)
2161                         return err;
2162         }
2163         *prev_link = 0;
2164
2165         return 0;
2166 }
2167
2168 int tipc_nl_link_dump(struct sk_buff *skb, struct netlink_callback *cb)
2169 {
2170         struct net *net = sock_net(skb->sk);
2171         struct tipc_net *tn = net_generic(net, tipc_net_id);
2172         struct tipc_node *node;
2173         struct tipc_nl_msg msg;
2174         u32 prev_node = cb->args[0];
2175         u32 prev_link = cb->args[1];
2176         int done = cb->args[2];
2177         int err;
2178
2179         if (done)
2180                 return 0;
2181
2182         msg.skb = skb;
2183         msg.portid = NETLINK_CB(cb->skb).portid;
2184         msg.seq = cb->nlh->nlmsg_seq;
2185
2186         rcu_read_lock();
2187
2188         if (prev_node) {
2189                 node = tipc_node_find(net, prev_node);
2190                 if (!node) {
2191                         /* We never set seq or call nl_dump_check_consistent()
2192                          * this means that setting prev_seq here will cause the
2193                          * consistence check to fail in the netlink callback
2194                          * handler. Resulting in the last NLMSG_DONE message
2195                          * having the NLM_F_DUMP_INTR flag set.
2196                          */
2197                         cb->prev_seq = 1;
2198                         goto out;
2199                 }
2200
2201                 list_for_each_entry_continue_rcu(node, &tn->node_list,
2202                                                  list) {
2203                         tipc_node_lock(node);
2204                         err = __tipc_nl_add_node_links(net, &msg, node,
2205                                                        &prev_link);
2206                         tipc_node_unlock(node);
2207                         if (err)
2208                                 goto out;
2209
2210                         prev_node = node->addr;
2211                 }
2212         } else {
2213                 err = tipc_nl_add_bc_link(net, &msg);
2214                 if (err)
2215                         goto out;
2216
2217                 list_for_each_entry_rcu(node, &tn->node_list, list) {
2218                         tipc_node_lock(node);
2219                         err = __tipc_nl_add_node_links(net, &msg, node,
2220                                                        &prev_link);
2221                         tipc_node_unlock(node);
2222                         if (err)
2223                                 goto out;
2224
2225                         prev_node = node->addr;
2226                 }
2227         }
2228         done = 1;
2229 out:
2230         rcu_read_unlock();
2231
2232         cb->args[0] = prev_node;
2233         cb->args[1] = prev_link;
2234         cb->args[2] = done;
2235
2236         return skb->len;
2237 }
2238
2239 int tipc_nl_link_get(struct sk_buff *skb, struct genl_info *info)
2240 {
2241         struct net *net = genl_info_net(info);
2242         struct sk_buff *ans_skb;
2243         struct tipc_nl_msg msg;
2244         struct tipc_link *link;
2245         struct tipc_node *node;
2246         char *name;
2247         int bearer_id;
2248         int err;
2249
2250         if (!info->attrs[TIPC_NLA_LINK_NAME])
2251                 return -EINVAL;
2252
2253         name = nla_data(info->attrs[TIPC_NLA_LINK_NAME]);
2254         node = tipc_link_find_owner(net, name, &bearer_id);
2255         if (!node)
2256                 return -EINVAL;
2257
2258         ans_skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
2259         if (!ans_skb)
2260                 return -ENOMEM;
2261
2262         msg.skb = ans_skb;
2263         msg.portid = info->snd_portid;
2264         msg.seq = info->snd_seq;
2265
2266         tipc_node_lock(node);
2267         link = node->links[bearer_id];
2268         if (!link) {
2269                 err = -EINVAL;
2270                 goto err_out;
2271         }
2272
2273         err = __tipc_nl_add_link(net, &msg, link);
2274         if (err)
2275                 goto err_out;
2276
2277         tipc_node_unlock(node);
2278
2279         return genlmsg_reply(ans_skb, info);
2280
2281 err_out:
2282         tipc_node_unlock(node);
2283         nlmsg_free(ans_skb);
2284
2285         return err;
2286 }
2287
2288 int tipc_nl_link_reset_stats(struct sk_buff *skb, struct genl_info *info)
2289 {
2290         int err;
2291         char *link_name;
2292         unsigned int bearer_id;
2293         struct tipc_link *link;
2294         struct tipc_node *node;
2295         struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
2296         struct net *net = sock_net(skb->sk);
2297
2298         if (!info->attrs[TIPC_NLA_LINK])
2299                 return -EINVAL;
2300
2301         err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
2302                                info->attrs[TIPC_NLA_LINK],
2303                                tipc_nl_link_policy);
2304         if (err)
2305                 return err;
2306
2307         if (!attrs[TIPC_NLA_LINK_NAME])
2308                 return -EINVAL;
2309
2310         link_name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
2311
2312         if (strcmp(link_name, tipc_bclink_name) == 0) {
2313                 err = tipc_bclink_reset_stats(net);
2314                 if (err)
2315                         return err;
2316                 return 0;
2317         }
2318
2319         node = tipc_link_find_owner(net, link_name, &bearer_id);
2320         if (!node)
2321                 return -EINVAL;
2322
2323         tipc_node_lock(node);
2324
2325         link = node->links[bearer_id];
2326         if (!link) {
2327                 tipc_node_unlock(node);
2328                 return -EINVAL;
2329         }
2330
2331         link_reset_statistics(link);
2332
2333         tipc_node_unlock(node);
2334
2335         return 0;
2336 }