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 struct tipc_link *tipc_parallel_link(struct tipc_link *l)
 143 {
 144         if (l->owner->active_links[0] != l)
 145                 return l->owner->active_links[0];
 146         return l->owner->active_links[1];
 147 }
 148
 149 static void link_init_max_pkt(struct tipc_link *l_ptr)
 150 {
 151         struct tipc_node *node = l_ptr->owner;
 152         struct tipc_net *tn = net_generic(node->net, tipc_net_id);
 153         struct tipc_bearer *b_ptr;
 154         u32 max_pkt;
 155
 156         rcu_read_lock();
 157         b_ptr = rcu_dereference_rtnl(tn->bearer_list[l_ptr->bearer_id]);
 158         if (!b_ptr) {
 159                 rcu_read_unlock();
 160                 return;
 161         }
 162         max_pkt = (b_ptr->mtu & ~3);
 163         rcu_read_unlock();
 164
 165         if (max_pkt > MAX_MSG_SIZE)
 166                 max_pkt = MAX_MSG_SIZE;
 167
 168         l_ptr->max_pkt_target = max_pkt;
 169         if (l_ptr->max_pkt_target < MAX_PKT_DEFAULT)
 170                 l_ptr->max_pkt = l_ptr->max_pkt_target;
 171         else
 172                 l_ptr->max_pkt = MAX_PKT_DEFAULT;
 173
 174         l_ptr->max_pkt_probes = 0;
 175 }
 176
 177 /*
 178  *  Simple non-static link routines (i.e. referenced outside this file)
 179  */
 180 int tipc_link_is_up(struct tipc_link *l_ptr)
 181 {
 182         if (!l_ptr)
 183                 return 0;
 184         return link_working_working(l_ptr) || link_working_unknown(l_ptr);
 185 }
 186
 187 int tipc_link_is_active(struct tipc_link *l_ptr)
 188 {
 189         return  (l_ptr->owner->active_links[0] == l_ptr) ||
 190                 (l_ptr->owner->active_links[1] == l_ptr);
 191 }
 192
 193 /**
 194  * link_timeout - handle expiration of link timer
 195  * @l_ptr: pointer to link
 196  */
 197 static void link_timeout(unsigned long data)
 198 {
 199         struct tipc_link *l_ptr = (struct tipc_link *)data;
 200         struct sk_buff *skb;
 201
 202         tipc_node_lock(l_ptr->owner);
 203
 204         /* update counters used in statistical profiling of send traffic */
 205         l_ptr->stats.accu_queue_sz += skb_queue_len(&l_ptr->transmq);
 206         l_ptr->stats.queue_sz_counts++;
 207
 208         skb = skb_peek(&l_ptr->transmq);
 209         if (skb) {
 210                 struct tipc_msg *msg = buf_msg(skb);
 211                 u32 length = msg_size(msg);
 212
 213                 if ((msg_user(msg) == MSG_FRAGMENTER) &&
 214                     (msg_type(msg) == FIRST_FRAGMENT)) {
 215                         length = msg_size(msg_get_wrapped(msg));
 216                 }
 217                 if (length) {
 218                         l_ptr->stats.msg_lengths_total += length;
 219                         l_ptr->stats.msg_length_counts++;
 220                         if (length <= 64)
 221                                 l_ptr->stats.msg_length_profile[0]++;
 222                         else if (length <= 256)
 223                                 l_ptr->stats.msg_length_profile[1]++;
 224                         else if (length <= 1024)
 225                                 l_ptr->stats.msg_length_profile[2]++;
 226                         else if (length <= 4096)
 227                                 l_ptr->stats.msg_length_profile[3]++;
 228                         else if (length <= 16384)
 229                                 l_ptr->stats.msg_length_profile[4]++;
 230                         else if (length <= 32768)
 231                                 l_ptr->stats.msg_length_profile[5]++;
 232                         else
 233                                 l_ptr->stats.msg_length_profile[6]++;
 234                 }
 235         }
 236
 237         /* do all other link processing performed on a periodic basis */
 238         link_state_event(l_ptr, TIMEOUT_EVT);
 239
 240         if (skb_queue_len(&l_ptr->backlogq))
 241                 tipc_link_push_packets(l_ptr);
 242
 243         tipc_node_unlock(l_ptr->owner);
 244         tipc_link_put(l_ptr);
 245 }
 246
 247 static void link_set_timer(struct tipc_link *link, unsigned long time)
 248 {
 249         if (!mod_timer(&link->timer, jiffies + time))
 250                 tipc_link_get(link);
 251 }
 252
 253 /**
 254  * tipc_link_create - create a new link
 255  * @n_ptr: pointer to associated node
 256  * @b_ptr: pointer to associated bearer
 257  * @media_addr: media address to use when sending messages over link
 258  *
 259  * Returns pointer to link.
 260  */
 261 struct tipc_link *tipc_link_create(struct tipc_node *n_ptr,
 262                                    struct tipc_bearer *b_ptr,
 263                                    const struct tipc_media_addr *media_addr)
 264 {
 265         struct tipc_net *tn = net_generic(n_ptr->net, tipc_net_id);
 266         struct tipc_link *l_ptr;
 267         struct tipc_msg *msg;
 268         char *if_name;
 269         char addr_string[16];
 270         u32 peer = n_ptr->addr;
 271
 272         if (n_ptr->link_cnt >= MAX_BEARERS) {
 273                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 274                 pr_err("Attempt to establish %uth link to %s. Max %u allowed.\n",
 275                         n_ptr->link_cnt, addr_string, MAX_BEARERS);
 276                 return NULL;
 277         }
 278
 279         if (n_ptr->links[b_ptr->identity]) {
 280                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 281                 pr_err("Attempt to establish second link on <%s> to %s\n",
 282                        b_ptr->name, addr_string);
 283                 return NULL;
 284         }
 285
 286         l_ptr = kzalloc(sizeof(*l_ptr), GFP_ATOMIC);
 287         if (!l_ptr) {
 288                 pr_warn("Link creation failed, no memory\n");
 289                 return NULL;
 290         }
 291         kref_init(&l_ptr->ref);
 292         l_ptr->addr = peer;
 293         if_name = strchr(b_ptr->name, ':') + 1;
 294         sprintf(l_ptr->name, "%u.%u.%u:%s-%u.%u.%u:unknown",
 295                 tipc_zone(tn->own_addr), tipc_cluster(tn->own_addr),
 296                 tipc_node(tn->own_addr),
 297                 if_name,
 298                 tipc_zone(peer), tipc_cluster(peer), tipc_node(peer));
 299                 /* note: peer i/f name is updated by reset/activate message */
 300         memcpy(&l_ptr->media_addr, media_addr, sizeof(*media_addr));
 301         l_ptr->owner = n_ptr;
 302         l_ptr->checkpoint = 1;
 303         l_ptr->peer_session = INVALID_SESSION;
 304         l_ptr->bearer_id = b_ptr->identity;
 305         link_set_supervision_props(l_ptr, b_ptr->tolerance);
 306         l_ptr->state = RESET_UNKNOWN;
 307
 308         l_ptr->pmsg = (struct tipc_msg *)&l_ptr->proto_msg;
 309         msg = l_ptr->pmsg;
 310         tipc_msg_init(tn->own_addr, msg, LINK_PROTOCOL, RESET_MSG, INT_H_SIZE,
 311                       l_ptr->addr);
 312         msg_set_size(msg, sizeof(l_ptr->proto_msg));
 313         msg_set_session(msg, (tn->random & 0xffff));
 314         msg_set_bearer_id(msg, b_ptr->identity);
 315         strcpy((char *)msg_data(msg), if_name);
 316         l_ptr->net_plane = b_ptr->net_plane;
 317         link_init_max_pkt(l_ptr);
 318         l_ptr->priority = b_ptr->priority;
 319         tipc_link_set_queue_limits(l_ptr, b_ptr->window);
 320         l_ptr->next_out_no = 1;
 321         __skb_queue_head_init(&l_ptr->transmq);
 322         __skb_queue_head_init(&l_ptr->backlogq);
 323         __skb_queue_head_init(&l_ptr->deferdq);
 324         skb_queue_head_init(&l_ptr->wakeupq);
 325         skb_queue_head_init(&l_ptr->inputq);
 326         skb_queue_head_init(&l_ptr->namedq);
 327         link_reset_statistics(l_ptr);
 328         tipc_node_attach_link(n_ptr, l_ptr);
 329         setup_timer(&l_ptr->timer, link_timeout, (unsigned long)l_ptr);
 330         link_state_event(l_ptr, STARTING_EVT);
 331
 332         return l_ptr;
 333 }
 334
 335 /**
 336  * link_delete - Conditional deletion of link.
 337  *               If timer still running, real delete is done when it expires
 338  * @link: link to be deleted
 339  */
 340 void tipc_link_delete(struct tipc_link *link)
 341 {
 342         tipc_link_reset_fragments(link);
 343         tipc_node_detach_link(link->owner, link);
 344         tipc_link_put(link);
 345 }
 346
 347 void tipc_link_delete_list(struct net *net, unsigned int bearer_id,
 348                            bool shutting_down)
 349 {
 350         struct tipc_net *tn = net_generic(net, tipc_net_id);
 351         struct tipc_link *link;
 352         struct tipc_node *node;
 353         bool del_link;
 354
 355         rcu_read_lock();
 356         list_for_each_entry_rcu(node, &tn->node_list, list) {
 357                 tipc_node_lock(node);
 358                 link = node->links[bearer_id];
 359                 if (!link) {
 360                         tipc_node_unlock(node);
 361                         continue;
 362                 }
 363                 del_link = !tipc_link_is_up(link) && !link->exp_msg_count;
 364                 tipc_link_reset(link);
 365                 if (del_timer(&link->timer))
 366                         tipc_link_put(link);
 367                 link->flags |= LINK_STOPPED;
 368                 /* Delete link now, or when failover is finished: */
 369                 if (shutting_down || !tipc_node_is_up(node) || del_link)
 370                         tipc_link_delete(link);
 371                 tipc_node_unlock(node);
 372         }
 373         rcu_read_unlock();
 374 }
 375
 376 /**
 377  * link_schedule_user - schedule a message sender for wakeup after congestion
 378  * @link: congested link
 379  * @list: message that was attempted sent
 380  * Create pseudo msg to send back to user when congestion abates
 381  * Only consumes message if there is an error
 382  */
 383 static int link_schedule_user(struct tipc_link *link, struct sk_buff_head *list)
 384 {
 385         struct tipc_msg *msg = buf_msg(skb_peek(list));
 386         int imp = msg_importance(msg);
 387         u32 oport = msg_origport(msg);
 388         u32 addr = link_own_addr(link);
 389         struct sk_buff *skb;
 390
 391         /* This really cannot happen...  */
 392         if (unlikely(imp > TIPC_CRITICAL_IMPORTANCE)) {
 393                 pr_warn("%s<%s>, send queue full", link_rst_msg, link->name);
 394                 tipc_link_reset(link);
 395                 goto err;
 396         }
 397         /* Non-blocking sender: */
 398         if (TIPC_SKB_CB(skb_peek(list))->wakeup_pending)
 399                 return -ELINKCONG;
 400
 401         /* Create and schedule wakeup pseudo message */
 402         skb = tipc_msg_create(SOCK_WAKEUP, 0, INT_H_SIZE, 0,
 403                               addr, addr, oport, 0, 0);
 404         if (!skb)
 405                 goto err;
 406         TIPC_SKB_CB(skb)->chain_sz = skb_queue_len(list);
 407         TIPC_SKB_CB(skb)->chain_imp = imp;
 408         skb_queue_tail(&link->wakeupq, skb);
 409         link->stats.link_congs++;
 410         return -ELINKCONG;
 411 err:
 412         __skb_queue_purge(list);
 413         return -ENOBUFS;
 414 }
 415
 416 /**
 417  * link_prepare_wakeup - prepare users for wakeup after congestion
 418  * @link: congested link
 419  * Move a number of waiting users, as permitted by available space in
 420  * the send queue, from link wait queue to node wait queue for wakeup
 421  */
 422 void link_prepare_wakeup(struct tipc_link *l)
 423 {
 424         int pnd[TIPC_SYSTEM_IMPORTANCE + 1] = {0,};
 425         int imp, lim;
 426         struct sk_buff *skb, *tmp;
 427
 428         skb_queue_walk_safe(&l->wakeupq, skb, tmp) {
 429                 imp = TIPC_SKB_CB(skb)->chain_imp;
 430                 lim = l->window + l->backlog[imp].limit;
 431                 pnd[imp] += TIPC_SKB_CB(skb)->chain_sz;
 432                 if ((pnd[imp] + l->backlog[imp].len) >= lim)
 433                         break;
 434                 skb_unlink(skb, &l->wakeupq);
 435                 skb_queue_tail(&l->inputq, skb);
 436                 l->owner->inputq = &l->inputq;
 437                 l->owner->action_flags |= TIPC_MSG_EVT;
 438         }
 439 }
 440
 441 /**
 442  * tipc_link_reset_fragments - purge link's inbound message fragments queue
 443  * @l_ptr: pointer to link
 444  */
 445 void tipc_link_reset_fragments(struct tipc_link *l_ptr)
 446 {
 447         kfree_skb(l_ptr->reasm_buf);
 448         l_ptr->reasm_buf = NULL;
 449 }
 450
 451 static void tipc_link_purge_backlog(struct tipc_link *l)
 452 {
 453         __skb_queue_purge(&l->backlogq);
 454         l->backlog[TIPC_LOW_IMPORTANCE].len = 0;
 455         l->backlog[TIPC_MEDIUM_IMPORTANCE].len = 0;
 456         l->backlog[TIPC_HIGH_IMPORTANCE].len = 0;
 457         l->backlog[TIPC_CRITICAL_IMPORTANCE].len = 0;
 458         l->backlog[TIPC_SYSTEM_IMPORTANCE].len = 0;
 459 }
 460
 461 /**
 462  * tipc_link_purge_queues - purge all pkt queues associated with link
 463  * @l_ptr: pointer to link
 464  */
 465 void tipc_link_purge_queues(struct tipc_link *l_ptr)
 466 {
 467         __skb_queue_purge(&l_ptr->deferdq);
 468         __skb_queue_purge(&l_ptr->transmq);
 469         tipc_link_purge_backlog(l_ptr);
 470         tipc_link_reset_fragments(l_ptr);
 471 }
 472
 473 void tipc_link_reset(struct tipc_link *l_ptr)
 474 {
 475         u32 prev_state = l_ptr->state;
 476         u32 checkpoint = l_ptr->next_in_no;
 477         int was_active_link = tipc_link_is_active(l_ptr);
 478         struct tipc_node *owner = l_ptr->owner;
 479
 480         msg_set_session(l_ptr->pmsg, ((msg_session(l_ptr->pmsg) + 1) & 0xffff));
 481
 482         /* Link is down, accept any session */
 483         l_ptr->peer_session = INVALID_SESSION;
 484
 485         /* Prepare for max packet size negotiation */
 486         link_init_max_pkt(l_ptr);
 487
 488         l_ptr->state = RESET_UNKNOWN;
 489
 490         if ((prev_state == RESET_UNKNOWN) || (prev_state == RESET_RESET))
 491                 return;
 492
 493         tipc_node_link_down(l_ptr->owner, l_ptr);
 494         tipc_bearer_remove_dest(owner->net, l_ptr->bearer_id, l_ptr->addr);
 495
 496         if (was_active_link && tipc_node_active_links(l_ptr->owner)) {
 497                 l_ptr->reset_checkpoint = checkpoint;
 498                 l_ptr->exp_msg_count = START_CHANGEOVER;
 499         }
 500
 501         /* Clean up all queues, except inputq: */
 502         __skb_queue_purge(&l_ptr->transmq);
 503         __skb_queue_purge(&l_ptr->deferdq);
 504         if (!owner->inputq)
 505                 owner->inputq = &l_ptr->inputq;
 506         skb_queue_splice_init(&l_ptr->wakeupq, owner->inputq);
 507         if (!skb_queue_empty(owner->inputq))
 508                 owner->action_flags |= TIPC_MSG_EVT;
 509         tipc_link_purge_backlog(l_ptr);
 510         l_ptr->rcv_unacked = 0;
 511         l_ptr->checkpoint = 1;
 512         l_ptr->next_out_no = 1;
 513         l_ptr->fsm_msg_cnt = 0;
 514         l_ptr->stale_count = 0;
 515         link_reset_statistics(l_ptr);
 516 }
 517
 518 void tipc_link_reset_list(struct net *net, unsigned int bearer_id)
 519 {
 520         struct tipc_net *tn = net_generic(net, tipc_net_id);
 521         struct tipc_link *l_ptr;
 522         struct tipc_node *n_ptr;
 523
 524         rcu_read_lock();
 525         list_for_each_entry_rcu(n_ptr, &tn->node_list, list) {
 526                 tipc_node_lock(n_ptr);
 527                 l_ptr = n_ptr->links[bearer_id];
 528                 if (l_ptr)
 529                         tipc_link_reset(l_ptr);
 530                 tipc_node_unlock(n_ptr);
 531         }
 532         rcu_read_unlock();
 533 }
 534
 535 static void link_activate(struct tipc_link *link)
 536 {
 537         struct tipc_node *node = link->owner;
 538
 539         link->next_in_no = 1;
 540         link->stats.recv_info = 1;
 541         tipc_node_link_up(node, link);
 542         tipc_bearer_add_dest(node->net, link->bearer_id, link->addr);
 543 }
 544
 545 /**
 546  * link_state_event - link finite state machine
 547  * @l_ptr: pointer to link
 548  * @event: state machine event to process
 549  */
 550 static void link_state_event(struct tipc_link *l_ptr, unsigned int event)
 551 {
 552         struct tipc_link *other;
 553         unsigned long cont_intv = l_ptr->cont_intv;
 554
 555         if (l_ptr->flags & LINK_STOPPED)
 556                 return;
 557
 558         if (!(l_ptr->flags & LINK_STARTED) && (event != STARTING_EVT))
 559                 return;         /* Not yet. */
 560
 561         /* Check whether changeover is going on */
 562         if (l_ptr->exp_msg_count) {
 563                 if (event == TIMEOUT_EVT)
 564                         link_set_timer(l_ptr, cont_intv);
 565                 return;
 566         }
 567
 568         switch (l_ptr->state) {
 569         case WORKING_WORKING:
 570                 switch (event) {
 571                 case TRAFFIC_MSG_EVT:
 572                 case ACTIVATE_MSG:
 573                         break;
 574                 case TIMEOUT_EVT:
 575                         if (l_ptr->next_in_no != l_ptr->checkpoint) {
 576                                 l_ptr->checkpoint = l_ptr->next_in_no;
 577                                 if (tipc_bclink_acks_missing(l_ptr->owner)) {
 578                                         tipc_link_proto_xmit(l_ptr, STATE_MSG,
 579                                                              0, 0, 0, 0, 0);
 580                                         l_ptr->fsm_msg_cnt++;
 581                                 } else if (l_ptr->max_pkt < l_ptr->max_pkt_target) {
 582                                         tipc_link_proto_xmit(l_ptr, STATE_MSG,
 583                                                              1, 0, 0, 0, 0);
 584                                         l_ptr->fsm_msg_cnt++;
 585                                 }
 586                                 link_set_timer(l_ptr, cont_intv);
 587                                 break;
 588                         }
 589                         l_ptr->state = WORKING_UNKNOWN;
 590                         l_ptr->fsm_msg_cnt = 0;
 591                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
 592                         l_ptr->fsm_msg_cnt++;
 593                         link_set_timer(l_ptr, cont_intv / 4);
 594                         break;
 595                 case RESET_MSG:
 596                         pr_debug("%s<%s>, requested by peer\n",
 597                                  link_rst_msg, l_ptr->name);
 598                         tipc_link_reset(l_ptr);
 599                         l_ptr->state = RESET_RESET;
 600                         l_ptr->fsm_msg_cnt = 0;
 601                         tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
 602                                              0, 0, 0, 0, 0);
 603                         l_ptr->fsm_msg_cnt++;
 604                         link_set_timer(l_ptr, cont_intv);
 605                         break;
 606                 default:
 607                         pr_debug("%s%u in WW state\n", link_unk_evt, event);
 608                 }
 609                 break;
 610         case WORKING_UNKNOWN:
 611                 switch (event) {
 612                 case TRAFFIC_MSG_EVT:
 613                 case ACTIVATE_MSG:
 614                         l_ptr->state = WORKING_WORKING;
 615                         l_ptr->fsm_msg_cnt = 0;
 616                         link_set_timer(l_ptr, cont_intv);
 617                         break;
 618                 case RESET_MSG:
 619                         pr_debug("%s<%s>, requested by peer while probing\n",
 620                                  link_rst_msg, l_ptr->name);
 621                         tipc_link_reset(l_ptr);
 622                         l_ptr->state = RESET_RESET;
 623                         l_ptr->fsm_msg_cnt = 0;
 624                         tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
 625                                              0, 0, 0, 0, 0);
 626                         l_ptr->fsm_msg_cnt++;
 627                         link_set_timer(l_ptr, cont_intv);
 628                         break;
 629                 case TIMEOUT_EVT:
 630                         if (l_ptr->next_in_no != l_ptr->checkpoint) {
 631                                 l_ptr->state = WORKING_WORKING;
 632                                 l_ptr->fsm_msg_cnt = 0;
 633                                 l_ptr->checkpoint = l_ptr->next_in_no;
 634                                 if (tipc_bclink_acks_missing(l_ptr->owner)) {
 635                                         tipc_link_proto_xmit(l_ptr, STATE_MSG,
 636                                                              0, 0, 0, 0, 0);
 637                                         l_ptr->fsm_msg_cnt++;
 638                                 }
 639                                 link_set_timer(l_ptr, cont_intv);
 640                         } else if (l_ptr->fsm_msg_cnt < l_ptr->abort_limit) {
 641                                 tipc_link_proto_xmit(l_ptr, STATE_MSG,
 642                                                      1, 0, 0, 0, 0);
 643                                 l_ptr->fsm_msg_cnt++;
 644                                 link_set_timer(l_ptr, cont_intv / 4);
 645                         } else {        /* Link has failed */
 646                                 pr_debug("%s<%s>, peer not responding\n",
 647                                          link_rst_msg, l_ptr->name);
 648                                 tipc_link_reset(l_ptr);
 649                                 l_ptr->state = RESET_UNKNOWN;
 650                                 l_ptr->fsm_msg_cnt = 0;
 651                                 tipc_link_proto_xmit(l_ptr, RESET_MSG,
 652                                                      0, 0, 0, 0, 0);
 653                                 l_ptr->fsm_msg_cnt++;
 654                                 link_set_timer(l_ptr, cont_intv);
 655                         }
 656                         break;
 657                 default:
 658                         pr_err("%s%u in WU state\n", link_unk_evt, event);
 659                 }
 660                 break;
 661         case RESET_UNKNOWN:
 662                 switch (event) {
 663                 case TRAFFIC_MSG_EVT:
 664                         break;
 665                 case ACTIVATE_MSG:
 666                         other = l_ptr->owner->active_links[0];
 667                         if (other && link_working_unknown(other))
 668                                 break;
 669                         l_ptr->state = WORKING_WORKING;
 670                         l_ptr->fsm_msg_cnt = 0;
 671                         link_activate(l_ptr);
 672                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
 673                         l_ptr->fsm_msg_cnt++;
 674                         if (l_ptr->owner->working_links == 1)
 675                                 tipc_link_sync_xmit(l_ptr);
 676                         link_set_timer(l_ptr, cont_intv);
 677                         break;
 678                 case RESET_MSG:
 679                         l_ptr->state = RESET_RESET;
 680                         l_ptr->fsm_msg_cnt = 0;
 681                         tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
 682                                              1, 0, 0, 0, 0);
 683                         l_ptr->fsm_msg_cnt++;
 684                         link_set_timer(l_ptr, cont_intv);
 685                         break;
 686                 case STARTING_EVT:
 687                         l_ptr->flags |= LINK_STARTED;
 688                         l_ptr->fsm_msg_cnt++;
 689                         link_set_timer(l_ptr, cont_intv);
 690                         break;
 691                 case TIMEOUT_EVT:
 692                         tipc_link_proto_xmit(l_ptr, RESET_MSG, 0, 0, 0, 0, 0);
 693                         l_ptr->fsm_msg_cnt++;
 694                         link_set_timer(l_ptr, cont_intv);
 695                         break;
 696                 default:
 697                         pr_err("%s%u in RU state\n", link_unk_evt, event);
 698                 }
 699                 break;
 700         case RESET_RESET:
 701                 switch (event) {
 702                 case TRAFFIC_MSG_EVT:
 703                 case ACTIVATE_MSG:
 704                         other = l_ptr->owner->active_links[0];
 705                         if (other && link_working_unknown(other))
 706                                 break;
 707                         l_ptr->state = WORKING_WORKING;
 708                         l_ptr->fsm_msg_cnt = 0;
 709                         link_activate(l_ptr);
 710                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
 711                         l_ptr->fsm_msg_cnt++;
 712                         if (l_ptr->owner->working_links == 1)
 713                                 tipc_link_sync_xmit(l_ptr);
 714                         link_set_timer(l_ptr, cont_intv);
 715                         break;
 716                 case RESET_MSG:
 717                         break;
 718                 case TIMEOUT_EVT:
 719                         tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
 720                                              0, 0, 0, 0, 0);
 721                         l_ptr->fsm_msg_cnt++;
 722                         link_set_timer(l_ptr, cont_intv);
 723                         break;
 724                 default:
 725                         pr_err("%s%u in RR state\n", link_unk_evt, event);
 726                 }
 727                 break;
 728         default:
 729                 pr_err("Unknown link state %u/%u\n", l_ptr->state, event);
 730         }
 731 }
 732
 733 /**
 734  * __tipc_link_xmit(): same as tipc_link_xmit, but destlink is known & locked
 735  * @link: link to use
 736  * @list: chain of buffers containing message
 737  *
 738  * Consumes the buffer chain, except when returning -ELINKCONG,
 739  * since the caller then may want to make more send attempts.
 740  * Returns 0 if success, or errno: -ELINKCONG, -EMSGSIZE or -ENOBUFS
 741  * Messages at TIPC_SYSTEM_IMPORTANCE are always accepted
 742  */
 743 int __tipc_link_xmit(struct net *net, struct tipc_link *link,
 744                      struct sk_buff_head *list)
 745 {
 746         struct tipc_msg *msg = buf_msg(skb_peek(list));
 747         unsigned int maxwin = link->window;
 748         unsigned int imp = msg_importance(msg);
 749         uint mtu = link->max_pkt;
 750         uint ack = mod(link->next_in_no - 1);
 751         uint seqno = link->next_out_no;
 752         uint bc_last_in = link->owner->bclink.last_in;
 753         struct tipc_media_addr *addr = &link->media_addr;
 754         struct sk_buff_head *transmq = &link->transmq;
 755         struct sk_buff_head *backlogq = &link->backlogq;
 756         struct sk_buff *skb, *tmp;
 757
 758         /* Match backlog limit against msg importance: */
 759         if (unlikely(link->backlog[imp].len >= link->backlog[imp].limit))
 760                 return link_schedule_user(link, list);
 761
 762         if (unlikely(msg_size(msg) > mtu)) {
 763                 __skb_queue_purge(list);
 764                 return -EMSGSIZE;
 765         }
 766         /* Prepare each packet for sending, and add to relevant queue: */
 767         skb_queue_walk_safe(list, skb, tmp) {
 768                 __skb_unlink(skb, list);
 769                 msg = buf_msg(skb);
 770                 msg_set_seqno(msg, seqno);
 771                 msg_set_ack(msg, ack);
 772                 msg_set_bcast_ack(msg, bc_last_in);
 773
 774                 if (likely(skb_queue_len(transmq) < maxwin)) {
 775                         __skb_queue_tail(transmq, skb);
 776                         tipc_bearer_send(net, link->bearer_id, skb, addr);
 777                         link->rcv_unacked = 0;
 778                         seqno++;
 779                         continue;
 780                 }
 781                 if (tipc_msg_bundle(skb_peek_tail(backlogq), skb, mtu)) {
 782                         link->stats.sent_bundled++;
 783                         continue;
 784                 }
 785                 if (tipc_msg_make_bundle(&skb, mtu, link->addr)) {
 786                         link->stats.sent_bundled++;
 787                         link->stats.sent_bundles++;
 788                         imp = msg_importance(buf_msg(skb));
 789                 }
 790                 __skb_queue_tail(backlogq, skb);
 791                 link->backlog[imp].len++;
 792                 seqno++;
 793         }
 794         link->next_out_no = seqno;
 795         return 0;
 796 }
 797
 798 static void skb2list(struct sk_buff *skb, struct sk_buff_head *list)
 799 {
 800         skb_queue_head_init(list);
 801         __skb_queue_tail(list, skb);
 802 }
 803
 804 static int __tipc_link_xmit_skb(struct tipc_link *link, struct sk_buff *skb)
 805 {
 806         struct sk_buff_head head;
 807
 808         skb2list(skb, &head);
 809         return __tipc_link_xmit(link->owner->net, link, &head);
 810 }
 811
 812 /* tipc_link_xmit_skb(): send single buffer to destination
 813  * Buffers sent via this functon are generally TIPC_SYSTEM_IMPORTANCE
 814  * messages, which will not be rejected
 815  * The only exception is datagram messages rerouted after secondary
 816  * lookup, which are rare and safe to dispose of anyway.
 817  * TODO: Return real return value, and let callers use
 818  * tipc_wait_for_sendpkt() where applicable
 819  */
 820 int tipc_link_xmit_skb(struct net *net, struct sk_buff *skb, u32 dnode,
 821                        u32 selector)
 822 {
 823         struct sk_buff_head head;
 824         int rc;
 825
 826         skb2list(skb, &head);
 827         rc = tipc_link_xmit(net, &head, dnode, selector);
 828         if (rc == -ELINKCONG)
 829                 kfree_skb(skb);
 830         return 0;
 831 }
 832
 833 /**
 834  * tipc_link_xmit() is the general link level function for message sending
 835  * @net: the applicable net namespace
 836  * @list: chain of buffers containing message
 837  * @dsz: amount of user data to be sent
 838  * @dnode: address of destination node
 839  * @selector: a number used for deterministic link selection
 840  * Consumes the buffer chain, except when returning -ELINKCONG
 841  * Returns 0 if success, otherwise errno: -ELINKCONG,-EHOSTUNREACH,-EMSGSIZE
 842  */
 843 int tipc_link_xmit(struct net *net, struct sk_buff_head *list, u32 dnode,
 844                    u32 selector)
 845 {
 846         struct tipc_link *link = NULL;
 847         struct tipc_node *node;
 848         int rc = -EHOSTUNREACH;
 849
 850         node = tipc_node_find(net, dnode);
 851         if (node) {
 852                 tipc_node_lock(node);
 853                 link = node->active_links[selector & 1];
 854                 if (link)
 855                         rc = __tipc_link_xmit(net, link, list);
 856                 tipc_node_unlock(node);
 857         }
 858         if (link)
 859                 return rc;
 860
 861         if (likely(in_own_node(net, dnode))) {
 862                 tipc_sk_rcv(net, list);
 863                 return 0;
 864         }
 865
 866         __skb_queue_purge(list);
 867         return rc;
 868 }
 869
 870 /*
 871  * tipc_link_sync_xmit - synchronize broadcast link endpoints.
 872  *
 873  * Give a newly added peer node the sequence number where it should
 874  * start receiving and acking broadcast packets.
 875  *
 876  * Called with node locked
 877  */
 878 static void tipc_link_sync_xmit(struct tipc_link *link)
 879 {
 880         struct sk_buff *skb;
 881         struct tipc_msg *msg;
 882
 883         skb = tipc_buf_acquire(INT_H_SIZE);
 884         if (!skb)
 885                 return;
 886
 887         msg = buf_msg(skb);
 888         tipc_msg_init(link_own_addr(link), msg, BCAST_PROTOCOL, STATE_MSG,
 889                       INT_H_SIZE, link->addr);
 890         msg_set_last_bcast(msg, link->owner->bclink.acked);
 891         __tipc_link_xmit_skb(link, skb);
 892 }
 893
 894 /*
 895  * tipc_link_sync_rcv - synchronize broadcast link endpoints.
 896  * Receive the sequence number where we should start receiving and
 897  * acking broadcast packets from a newly added peer node, and open
 898  * up for reception of such packets.
 899  *
 900  * Called with node locked
 901  */
 902 static void tipc_link_sync_rcv(struct tipc_node *n, struct sk_buff *buf)
 903 {
 904         struct tipc_msg *msg = buf_msg(buf);
 905
 906         n->bclink.last_sent = n->bclink.last_in = msg_last_bcast(msg);
 907         n->bclink.recv_permitted = true;
 908         kfree_skb(buf);
 909 }
 910
 911 /*
 912  * tipc_link_push_packets - push unsent packets to bearer
 913  *
 914  * Push out the unsent messages of a link where congestion
 915  * has abated. Node is locked.
 916  *
 917  * Called with node locked
 918  */
 919 void tipc_link_push_packets(struct tipc_link *link)
 920 {
 921         struct sk_buff *skb;
 922         struct tipc_msg *msg;
 923         unsigned int ack = mod(link->next_in_no - 1);
 924
 925         while (skb_queue_len(&link->transmq) < link->window) {
 926                 skb = __skb_dequeue(&link->backlogq);
 927                 if (!skb)
 928                         break;
 929                 msg = buf_msg(skb);
 930                 link->backlog[msg_importance(msg)].len--;
 931                 msg_set_ack(msg, ack);
 932                 msg_set_bcast_ack(msg, link->owner->bclink.last_in);
 933                 link->rcv_unacked = 0;
 934                 __skb_queue_tail(&link->transmq, skb);
 935                 tipc_bearer_send(link->owner->net, link->bearer_id,
 936                                  skb, &link->media_addr);
 937         }
 938 }
 939
 940 void tipc_link_reset_all(struct tipc_node *node)
 941 {
 942         char addr_string[16];
 943         u32 i;
 944
 945         tipc_node_lock(node);
 946
 947         pr_warn("Resetting all links to %s\n",
 948                 tipc_addr_string_fill(addr_string, node->addr));
 949
 950         for (i = 0; i < MAX_BEARERS; i++) {
 951                 if (node->links[i]) {
 952                         link_print(node->links[i], "Resetting link\n");
 953                         tipc_link_reset(node->links[i]);
 954                 }
 955         }
 956
 957         tipc_node_unlock(node);
 958 }
 959
 960 static void link_retransmit_failure(struct tipc_link *l_ptr,
 961                                     struct sk_buff *buf)
 962 {
 963         struct tipc_msg *msg = buf_msg(buf);
 964         struct net *net = l_ptr->owner->net;
 965
 966         pr_warn("Retransmission failure on link <%s>\n", l_ptr->name);
 967
 968         if (l_ptr->addr) {
 969                 /* Handle failure on standard link */
 970                 link_print(l_ptr, "Resetting link\n");
 971                 tipc_link_reset(l_ptr);
 972
 973         } else {
 974                 /* Handle failure on broadcast link */
 975                 struct tipc_node *n_ptr;
 976                 char addr_string[16];
 977
 978                 pr_info("Msg seq number: %u,  ", msg_seqno(msg));
 979                 pr_cont("Outstanding acks: %lu\n",
 980                         (unsigned long) TIPC_SKB_CB(buf)->handle);
 981
 982                 n_ptr = tipc_bclink_retransmit_to(net);
 983
 984                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 985                 pr_info("Broadcast link info for %s\n", addr_string);
 986                 pr_info("Reception permitted: %d,  Acked: %u\n",
 987                         n_ptr->bclink.recv_permitted,
 988                         n_ptr->bclink.acked);
 989                 pr_info("Last in: %u,  Oos state: %u,  Last sent: %u\n",
 990                         n_ptr->bclink.last_in,
 991                         n_ptr->bclink.oos_state,
 992                         n_ptr->bclink.last_sent);
 993
 994                 n_ptr->action_flags |= TIPC_BCAST_RESET;
 995                 l_ptr->stale_count = 0;
 996         }
 997 }
 998
 999 void tipc_link_retransmit(struct tipc_link *l_ptr, struct sk_buff *skb,
1000                           u32 retransmits)
1001 {
1002         struct tipc_msg *msg;
1003
1004         if (!skb)
1005                 return;
1006
1007         msg = buf_msg(skb);
1008
1009         /* Detect repeated retransmit failures */
1010         if (l_ptr->last_retransmitted == msg_seqno(msg)) {
1011                 if (++l_ptr->stale_count > 100) {
1012                         link_retransmit_failure(l_ptr, skb);
1013                         return;
1014                 }
1015         } else {
1016                 l_ptr->last_retransmitted = msg_seqno(msg);
1017                 l_ptr->stale_count = 1;
1018         }
1019
1020         skb_queue_walk_from(&l_ptr->transmq, skb) {
1021                 if (!retransmits)
1022                         break;
1023                 msg = buf_msg(skb);
1024                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1025                 msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1026                 tipc_bearer_send(l_ptr->owner->net, l_ptr->bearer_id, skb,
1027                                  &l_ptr->media_addr);
1028                 retransmits--;
1029                 l_ptr->stats.retransmitted++;
1030         }
1031 }
1032
1033 /* link_synch(): check if all packets arrived before the synch
1034  *               point have been consumed
1035  * Returns true if the parallel links are synched, otherwise false
1036  */
1037 static bool link_synch(struct tipc_link *l)
1038 {
1039         unsigned int post_synch;
1040         struct tipc_link *pl;
1041
1042         pl  = tipc_parallel_link(l);
1043         if (pl == l)
1044                 goto synched;
1045
1046         /* Was last pre-synch packet added to input queue ? */
1047         if (less_eq(pl->next_in_no, l->synch_point))
1048                 return false;
1049
1050         /* Is it still in the input queue ? */
1051         post_synch = mod(pl->next_in_no - l->synch_point) - 1;
1052         if (skb_queue_len(&pl->inputq) > post_synch)
1053                 return false;
1054 synched:
1055         l->flags &= ~LINK_SYNCHING;
1056         return true;
1057 }
1058
1059 static void link_retrieve_defq(struct tipc_link *link,
1060                                struct sk_buff_head *list)
1061 {
1062         u32 seq_no;
1063
1064         if (skb_queue_empty(&link->deferdq))
1065                 return;
1066
1067         seq_no = buf_seqno(skb_peek(&link->deferdq));
1068         if (seq_no == mod(link->next_in_no))
1069                 skb_queue_splice_tail_init(&link->deferdq, list);
1070 }
1071
1072 /**
1073  * tipc_rcv - process TIPC packets/messages arriving from off-node
1074  * @net: the applicable net namespace
1075  * @skb: TIPC packet
1076  * @b_ptr: pointer to bearer message arrived on
1077  *
1078  * Invoked with no locks held.  Bearer pointer must point to a valid bearer
1079  * structure (i.e. cannot be NULL), but bearer can be inactive.
1080  */
1081 void tipc_rcv(struct net *net, struct sk_buff *skb, struct tipc_bearer *b_ptr)
1082 {
1083         struct tipc_net *tn = net_generic(net, tipc_net_id);
1084         struct sk_buff_head head;
1085         struct tipc_node *n_ptr;
1086         struct tipc_link *l_ptr;
1087         struct sk_buff *skb1, *tmp;
1088         struct tipc_msg *msg;
1089         u32 seq_no;
1090         u32 ackd;
1091         u32 released;
1092
1093         skb2list(skb, &head);
1094
1095         while ((skb = __skb_dequeue(&head))) {
1096                 /* Ensure message is well-formed */
1097                 if (unlikely(!tipc_msg_validate(skb)))
1098                         goto discard;
1099
1100                 /* Handle arrival of a non-unicast link message */
1101                 msg = buf_msg(skb);
1102                 if (unlikely(msg_non_seq(msg))) {
1103                         if (msg_user(msg) ==  LINK_CONFIG)
1104                                 tipc_disc_rcv(net, skb, b_ptr);
1105                         else
1106                                 tipc_bclink_rcv(net, skb);
1107                         continue;
1108                 }
1109
1110                 /* Discard unicast link messages destined for another node */
1111                 if (unlikely(!msg_short(msg) &&
1112                              (msg_destnode(msg) != tn->own_addr)))
1113                         goto discard;
1114
1115                 /* Locate neighboring node that sent message */
1116                 n_ptr = tipc_node_find(net, msg_prevnode(msg));
1117                 if (unlikely(!n_ptr))
1118                         goto discard;
1119                 tipc_node_lock(n_ptr);
1120
1121                 /* Locate unicast link endpoint that should handle message */
1122                 l_ptr = n_ptr->links[b_ptr->identity];
1123                 if (unlikely(!l_ptr))
1124                         goto unlock;
1125
1126                 /* Verify that communication with node is currently allowed */
1127                 if ((n_ptr->action_flags & TIPC_WAIT_PEER_LINKS_DOWN) &&
1128                     msg_user(msg) == LINK_PROTOCOL &&
1129                     (msg_type(msg) == RESET_MSG ||
1130                     msg_type(msg) == ACTIVATE_MSG) &&
1131                     !msg_redundant_link(msg))
1132                         n_ptr->action_flags &= ~TIPC_WAIT_PEER_LINKS_DOWN;
1133
1134                 if (tipc_node_blocked(n_ptr))
1135                         goto unlock;
1136
1137                 /* Validate message sequence number info */
1138                 seq_no = msg_seqno(msg);
1139                 ackd = msg_ack(msg);
1140
1141                 /* Release acked messages */
1142                 if (unlikely(n_ptr->bclink.acked != msg_bcast_ack(msg)))
1143                         tipc_bclink_acknowledge(n_ptr, msg_bcast_ack(msg));
1144
1145                 released = 0;
1146                 skb_queue_walk_safe(&l_ptr->transmq, skb1, tmp) {
1147                         if (more(buf_seqno(skb1), ackd))
1148                                 break;
1149                          __skb_unlink(skb1, &l_ptr->transmq);
1150                          kfree_skb(skb1);
1151                          released = 1;
1152                 }
1153
1154                 /* Try sending any messages link endpoint has pending */
1155                 if (unlikely(skb_queue_len(&l_ptr->backlogq)))
1156                         tipc_link_push_packets(l_ptr);
1157
1158                 if (released && !skb_queue_empty(&l_ptr->wakeupq))
1159                         link_prepare_wakeup(l_ptr);
1160
1161                 /* Process the incoming packet */
1162                 if (unlikely(!link_working_working(l_ptr))) {
1163                         if (msg_user(msg) == LINK_PROTOCOL) {
1164                                 tipc_link_proto_rcv(l_ptr, skb);
1165                                 link_retrieve_defq(l_ptr, &head);
1166                                 skb = NULL;
1167                                 goto unlock;
1168                         }
1169
1170                         /* Traffic message. Conditionally activate link */
1171                         link_state_event(l_ptr, TRAFFIC_MSG_EVT);
1172
1173                         if (link_working_working(l_ptr)) {
1174                                 /* Re-insert buffer in front of queue */
1175                                 __skb_queue_head(&head, skb);
1176                                 skb = NULL;
1177                                 goto unlock;
1178                         }
1179                         goto unlock;
1180                 }
1181
1182                 /* Link is now in state WORKING_WORKING */
1183                 if (unlikely(seq_no != mod(l_ptr->next_in_no))) {
1184                         link_handle_out_of_seq_msg(l_ptr, skb);
1185                         link_retrieve_defq(l_ptr, &head);
1186                         skb = NULL;
1187                         goto unlock;
1188                 }
1189                 /* Synchronize with parallel link if applicable */
1190                 if (unlikely((l_ptr->flags & LINK_SYNCHING) && !msg_dup(msg))) {
1191                         link_handle_out_of_seq_msg(l_ptr, skb);
1192                         if (link_synch(l_ptr))
1193                                 link_retrieve_defq(l_ptr, &head);
1194                         skb = NULL;
1195                         goto unlock;
1196                 }
1197                 l_ptr->next_in_no++;
1198                 if (unlikely(!skb_queue_empty(&l_ptr->deferdq)))
1199                         link_retrieve_defq(l_ptr, &head);
1200                 if (unlikely(++l_ptr->rcv_unacked >= TIPC_MIN_LINK_WIN)) {
1201                         l_ptr->stats.sent_acks++;
1202                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
1203                 }
1204                 tipc_link_input(l_ptr, skb);
1205                 skb = NULL;
1206 unlock:
1207                 tipc_node_unlock(n_ptr);
1208 discard:
1209                 if (unlikely(skb))
1210                         kfree_skb(skb);
1211         }
1212 }
1213
1214 /* tipc_data_input - deliver data and name distr msgs to upper layer
1215  *
1216  * Consumes buffer if message is of right type
1217  * Node lock must be held
1218  */
1219 static bool tipc_data_input(struct tipc_link *link, struct sk_buff *skb)
1220 {
1221         struct tipc_node *node = link->owner;
1222         struct tipc_msg *msg = buf_msg(skb);
1223         u32 dport = msg_destport(msg);
1224
1225         switch (msg_user(msg)) {
1226         case TIPC_LOW_IMPORTANCE:
1227         case TIPC_MEDIUM_IMPORTANCE:
1228         case TIPC_HIGH_IMPORTANCE:
1229         case TIPC_CRITICAL_IMPORTANCE:
1230         case CONN_MANAGER:
1231                 if (tipc_skb_queue_tail(&link->inputq, skb, dport)) {
1232                         node->inputq = &link->inputq;
1233                         node->action_flags |= TIPC_MSG_EVT;
1234                 }
1235                 return true;
1236         case NAME_DISTRIBUTOR:
1237                 node->bclink.recv_permitted = true;
1238                 node->namedq = &link->namedq;
1239                 skb_queue_tail(&link->namedq, skb);
1240                 if (skb_queue_len(&link->namedq) == 1)
1241                         node->action_flags |= TIPC_NAMED_MSG_EVT;
1242                 return true;
1243         case MSG_BUNDLER:
1244         case CHANGEOVER_PROTOCOL:
1245         case MSG_FRAGMENTER:
1246         case BCAST_PROTOCOL:
1247                 return false;
1248         default:
1249                 pr_warn("Dropping received illegal msg type\n");
1250                 kfree_skb(skb);
1251                 return false;
1252         };
1253 }
1254
1255 /* tipc_link_input - process packet that has passed link protocol check
1256  *
1257  * Consumes buffer
1258  * Node lock must be held
1259  */
1260 static void tipc_link_input(struct tipc_link *link, struct sk_buff *skb)
1261 {
1262         struct tipc_node *node = link->owner;
1263         struct tipc_msg *msg = buf_msg(skb);
1264         struct sk_buff *iskb;
1265         int pos = 0;
1266
1267         if (likely(tipc_data_input(link, skb)))
1268                 return;
1269
1270         switch (msg_user(msg)) {
1271         case CHANGEOVER_PROTOCOL:
1272                 if (msg_dup(msg)) {
1273                         link->flags |= LINK_SYNCHING;
1274                         link->synch_point = msg_seqno(msg_get_wrapped(msg));
1275                 }
1276                 if (!tipc_link_tunnel_rcv(node, &skb))
1277                         break;
1278                 if (msg_user(buf_msg(skb)) != MSG_BUNDLER) {
1279                         tipc_data_input(link, skb);
1280                         break;
1281                 }
1282         case MSG_BUNDLER:
1283                 link->stats.recv_bundles++;
1284                 link->stats.recv_bundled += msg_msgcnt(msg);
1285
1286                 while (tipc_msg_extract(skb, &iskb, &pos))
1287                         tipc_data_input(link, iskb);
1288                 break;
1289         case MSG_FRAGMENTER:
1290                 link->stats.recv_fragments++;
1291                 if (tipc_buf_append(&link->reasm_buf, &skb)) {
1292                         link->stats.recv_fragmented++;
1293                         tipc_data_input(link, skb);
1294                 } else if (!link->reasm_buf) {
1295                         tipc_link_reset(link);
1296                 }
1297                 break;
1298         case BCAST_PROTOCOL:
1299                 tipc_link_sync_rcv(node, skb);
1300                 break;
1301         default:
1302                 break;
1303         };
1304 }
1305
1306 /**
1307  * tipc_link_defer_pkt - Add out-of-sequence message to deferred reception queue
1308  *
1309  * Returns increase in queue length (i.e. 0 or 1)
1310  */
1311 u32 tipc_link_defer_pkt(struct sk_buff_head *list, struct sk_buff *skb)
1312 {
1313         struct sk_buff *skb1;
1314         u32 seq_no = buf_seqno(skb);
1315
1316         /* Empty queue ? */
1317         if (skb_queue_empty(list)) {
1318                 __skb_queue_tail(list, skb);
1319                 return 1;
1320         }
1321
1322         /* Last ? */
1323         if (less(buf_seqno(skb_peek_tail(list)), seq_no)) {
1324                 __skb_queue_tail(list, skb);
1325                 return 1;
1326         }
1327
1328         /* Locate insertion point in queue, then insert; discard if duplicate */
1329         skb_queue_walk(list, skb1) {
1330                 u32 curr_seqno = buf_seqno(skb1);
1331
1332                 if (seq_no == curr_seqno) {
1333                         kfree_skb(skb);
1334                         return 0;
1335                 }
1336
1337                 if (less(seq_no, curr_seqno))
1338                         break;
1339         }
1340
1341         __skb_queue_before(list, skb1, skb);
1342         return 1;
1343 }
1344
1345 /*
1346  * link_handle_out_of_seq_msg - handle arrival of out-of-sequence packet
1347  */
1348 static void link_handle_out_of_seq_msg(struct tipc_link *l_ptr,
1349                                        struct sk_buff *buf)
1350 {
1351         u32 seq_no = buf_seqno(buf);
1352
1353         if (likely(msg_user(buf_msg(buf)) == LINK_PROTOCOL)) {
1354                 tipc_link_proto_rcv(l_ptr, buf);
1355                 return;
1356         }
1357
1358         /* Record OOS packet arrival (force mismatch on next timeout) */
1359         l_ptr->checkpoint--;
1360
1361         /*
1362          * Discard packet if a duplicate; otherwise add it to deferred queue
1363          * and notify peer of gap as per protocol specification
1364          */
1365         if (less(seq_no, mod(l_ptr->next_in_no))) {
1366                 l_ptr->stats.duplicates++;
1367                 kfree_skb(buf);
1368                 return;
1369         }
1370
1371         if (tipc_link_defer_pkt(&l_ptr->deferdq, buf)) {
1372                 l_ptr->stats.deferred_recv++;
1373                 if ((skb_queue_len(&l_ptr->deferdq) % TIPC_MIN_LINK_WIN) == 1)
1374                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
1375         } else {
1376                 l_ptr->stats.duplicates++;
1377         }
1378 }
1379
1380 /*
1381  * Send protocol message to the other endpoint.
1382  */
1383 void tipc_link_proto_xmit(struct tipc_link *l_ptr, u32 msg_typ, int probe_msg,
1384                           u32 gap, u32 tolerance, u32 priority, u32 ack_mtu)
1385 {
1386         struct sk_buff *buf = NULL;
1387         struct tipc_msg *msg = l_ptr->pmsg;
1388         u32 msg_size = sizeof(l_ptr->proto_msg);
1389         int r_flag;
1390
1391         /* Don't send protocol message during link changeover */
1392         if (l_ptr->exp_msg_count)
1393                 return;
1394
1395         /* Abort non-RESET send if communication with node is prohibited */
1396         if ((tipc_node_blocked(l_ptr->owner)) && (msg_typ != RESET_MSG))
1397                 return;
1398
1399         /* Create protocol message with "out-of-sequence" sequence number */
1400         msg_set_type(msg, msg_typ);
1401         msg_set_net_plane(msg, l_ptr->net_plane);
1402         msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1403         msg_set_last_bcast(msg, tipc_bclink_get_last_sent(l_ptr->owner->net));
1404
1405         if (msg_typ == STATE_MSG) {
1406                 u32 next_sent = mod(l_ptr->next_out_no);
1407
1408                 if (!tipc_link_is_up(l_ptr))
1409                         return;
1410                 if (skb_queue_len(&l_ptr->backlogq))
1411                         next_sent = buf_seqno(skb_peek(&l_ptr->backlogq));
1412                 msg_set_next_sent(msg, next_sent);
1413                 if (!skb_queue_empty(&l_ptr->deferdq)) {
1414                         u32 rec = buf_seqno(skb_peek(&l_ptr->deferdq));
1415                         gap = mod(rec - mod(l_ptr->next_in_no));
1416                 }
1417                 msg_set_seq_gap(msg, gap);
1418                 if (gap)
1419                         l_ptr->stats.sent_nacks++;
1420                 msg_set_link_tolerance(msg, tolerance);
1421                 msg_set_linkprio(msg, priority);
1422                 msg_set_max_pkt(msg, ack_mtu);
1423                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1424                 msg_set_probe(msg, probe_msg != 0);
1425                 if (probe_msg) {
1426                         u32 mtu = l_ptr->max_pkt;
1427
1428                         if ((mtu < l_ptr->max_pkt_target) &&
1429                             link_working_working(l_ptr) &&
1430                             l_ptr->fsm_msg_cnt) {
1431                                 msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
1432                                 if (l_ptr->max_pkt_probes == 10) {
1433                                         l_ptr->max_pkt_target = (msg_size - 4);
1434                                         l_ptr->max_pkt_probes = 0;
1435                                         msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
1436                                 }
1437                                 l_ptr->max_pkt_probes++;
1438                         }
1439
1440                         l_ptr->stats.sent_probes++;
1441                 }
1442                 l_ptr->stats.sent_states++;
1443         } else {                /* RESET_MSG or ACTIVATE_MSG */
1444                 msg_set_ack(msg, mod(l_ptr->reset_checkpoint - 1));
1445                 msg_set_seq_gap(msg, 0);
1446                 msg_set_next_sent(msg, 1);
1447                 msg_set_probe(msg, 0);
1448                 msg_set_link_tolerance(msg, l_ptr->tolerance);
1449                 msg_set_linkprio(msg, l_ptr->priority);
1450                 msg_set_max_pkt(msg, l_ptr->max_pkt_target);
1451         }
1452
1453         r_flag = (l_ptr->owner->working_links > tipc_link_is_up(l_ptr));
1454         msg_set_redundant_link(msg, r_flag);
1455         msg_set_linkprio(msg, l_ptr->priority);
1456         msg_set_size(msg, msg_size);
1457
1458         msg_set_seqno(msg, mod(l_ptr->next_out_no + (0xffff/2)));
1459
1460         buf = tipc_buf_acquire(msg_size);
1461         if (!buf)
1462                 return;
1463
1464         skb_copy_to_linear_data(buf, msg, sizeof(l_ptr->proto_msg));
1465         buf->priority = TC_PRIO_CONTROL;
1466         tipc_bearer_send(l_ptr->owner->net, l_ptr->bearer_id, buf,
1467                          &l_ptr->media_addr);
1468         l_ptr->rcv_unacked = 0;
1469         kfree_skb(buf);
1470 }
1471
1472 /*
1473  * Receive protocol message :
1474  * Note that network plane id propagates through the network, and may
1475  * change at any time. The node with lowest address rules
1476  */
1477 static void tipc_link_proto_rcv(struct tipc_link *l_ptr,
1478                                 struct sk_buff *buf)
1479 {
1480         u32 rec_gap = 0;
1481         u32 max_pkt_info;
1482         u32 max_pkt_ack;
1483         u32 msg_tol;
1484         struct tipc_msg *msg = buf_msg(buf);
1485
1486         /* Discard protocol message during link changeover */
1487         if (l_ptr->exp_msg_count)
1488                 goto exit;
1489
1490         if (l_ptr->net_plane != msg_net_plane(msg))
1491                 if (link_own_addr(l_ptr) > msg_prevnode(msg))
1492                         l_ptr->net_plane = msg_net_plane(msg);
1493
1494         switch (msg_type(msg)) {
1495
1496         case RESET_MSG:
1497                 if (!link_working_unknown(l_ptr) &&
1498                     (l_ptr->peer_session != INVALID_SESSION)) {
1499                         if (less_eq(msg_session(msg), l_ptr->peer_session))
1500                                 break; /* duplicate or old reset: ignore */
1501                 }
1502
1503                 if (!msg_redundant_link(msg) && (link_working_working(l_ptr) ||
1504                                 link_working_unknown(l_ptr))) {
1505                         /*
1506                          * peer has lost contact -- don't allow peer's links
1507                          * to reactivate before we recognize loss & clean up
1508                          */
1509                         l_ptr->owner->action_flags |= TIPC_WAIT_OWN_LINKS_DOWN;
1510                 }
1511
1512                 link_state_event(l_ptr, RESET_MSG);
1513
1514                 /* fall thru' */
1515         case ACTIVATE_MSG:
1516                 /* Update link settings according other endpoint's values */
1517                 strcpy((strrchr(l_ptr->name, ':') + 1), (char *)msg_data(msg));
1518
1519                 msg_tol = msg_link_tolerance(msg);
1520                 if (msg_tol > l_ptr->tolerance)
1521                         link_set_supervision_props(l_ptr, msg_tol);
1522
1523                 if (msg_linkprio(msg) > l_ptr->priority)
1524                         l_ptr->priority = msg_linkprio(msg);
1525
1526                 max_pkt_info = msg_max_pkt(msg);
1527                 if (max_pkt_info) {
1528                         if (max_pkt_info < l_ptr->max_pkt_target)
1529                                 l_ptr->max_pkt_target = max_pkt_info;
1530                         if (l_ptr->max_pkt > l_ptr->max_pkt_target)
1531                                 l_ptr->max_pkt = l_ptr->max_pkt_target;
1532                 } else {
1533                         l_ptr->max_pkt = l_ptr->max_pkt_target;
1534                 }
1535
1536                 /* Synchronize broadcast link info, if not done previously */
1537                 if (!tipc_node_is_up(l_ptr->owner)) {
1538                         l_ptr->owner->bclink.last_sent =
1539                                 l_ptr->owner->bclink.last_in =
1540                                 msg_last_bcast(msg);
1541                         l_ptr->owner->bclink.oos_state = 0;
1542                 }
1543
1544                 l_ptr->peer_session = msg_session(msg);
1545                 l_ptr->peer_bearer_id = msg_bearer_id(msg);
1546
1547                 if (msg_type(msg) == ACTIVATE_MSG)
1548                         link_state_event(l_ptr, ACTIVATE_MSG);
1549                 break;
1550         case STATE_MSG:
1551
1552                 msg_tol = msg_link_tolerance(msg);
1553                 if (msg_tol)
1554                         link_set_supervision_props(l_ptr, msg_tol);
1555
1556                 if (msg_linkprio(msg) &&
1557                     (msg_linkprio(msg) != l_ptr->priority)) {
1558                         pr_debug("%s<%s>, priority change %u->%u\n",
1559                                  link_rst_msg, l_ptr->name,
1560                                  l_ptr->priority, msg_linkprio(msg));
1561                         l_ptr->priority = msg_linkprio(msg);
1562                         tipc_link_reset(l_ptr); /* Enforce change to take effect */
1563                         break;
1564                 }
1565
1566                 /* Record reception; force mismatch at next timeout: */
1567                 l_ptr->checkpoint--;
1568
1569                 link_state_event(l_ptr, TRAFFIC_MSG_EVT);
1570                 l_ptr->stats.recv_states++;
1571                 if (link_reset_unknown(l_ptr))
1572                         break;
1573
1574                 if (less_eq(mod(l_ptr->next_in_no), msg_next_sent(msg))) {
1575                         rec_gap = mod(msg_next_sent(msg) -
1576                                       mod(l_ptr->next_in_no));
1577                 }
1578
1579                 max_pkt_ack = msg_max_pkt(msg);
1580                 if (max_pkt_ack > l_ptr->max_pkt) {
1581                         l_ptr->max_pkt = max_pkt_ack;
1582                         l_ptr->max_pkt_probes = 0;
1583                 }
1584
1585                 max_pkt_ack = 0;
1586                 if (msg_probe(msg)) {
1587                         l_ptr->stats.recv_probes++;
1588                         if (msg_size(msg) > sizeof(l_ptr->proto_msg))
1589                                 max_pkt_ack = msg_size(msg);
1590                 }
1591
1592                 /* Protocol message before retransmits, reduce loss risk */
1593                 if (l_ptr->owner->bclink.recv_permitted)
1594                         tipc_bclink_update_link_state(l_ptr->owner,
1595                                                       msg_last_bcast(msg));
1596
1597                 if (rec_gap || (msg_probe(msg))) {
1598                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, rec_gap, 0,
1599                                              0, max_pkt_ack);
1600                 }
1601                 if (msg_seq_gap(msg)) {
1602                         l_ptr->stats.recv_nacks++;
1603                         tipc_link_retransmit(l_ptr, skb_peek(&l_ptr->transmq),
1604                                              msg_seq_gap(msg));
1605                 }
1606                 break;
1607         }
1608 exit:
1609         kfree_skb(buf);
1610 }
1611
1612
1613 /* tipc_link_tunnel_xmit(): Tunnel one packet via a link belonging to
1614  * a different bearer. Owner node is locked.
1615  */
1616 static void tipc_link_tunnel_xmit(struct tipc_link *l_ptr,
1617                                   struct tipc_msg *tunnel_hdr,
1618                                   struct tipc_msg *msg,
1619                                   u32 selector)
1620 {
1621         struct tipc_link *tunnel;
1622         struct sk_buff *skb;
1623         u32 length = msg_size(msg);
1624
1625         tunnel = l_ptr->owner->active_links[selector & 1];
1626         if (!tipc_link_is_up(tunnel)) {
1627                 pr_warn("%stunnel link no longer available\n", link_co_err);
1628                 return;
1629         }
1630         msg_set_size(tunnel_hdr, length + INT_H_SIZE);
1631         skb = tipc_buf_acquire(length + INT_H_SIZE);
1632         if (!skb) {
1633                 pr_warn("%sunable to send tunnel msg\n", link_co_err);
1634                 return;
1635         }
1636         skb_copy_to_linear_data(skb, tunnel_hdr, INT_H_SIZE);
1637         skb_copy_to_linear_data_offset(skb, INT_H_SIZE, msg, length);
1638         __tipc_link_xmit_skb(tunnel, skb);
1639 }
1640
1641
1642 /* tipc_link_failover_send_queue(): A link has gone down, but a second
1643  * link is still active. We can do failover. Tunnel the failing link's
1644  * whole send queue via the remaining link. This way, we don't lose
1645  * any packets, and sequence order is preserved for subsequent traffic
1646  * sent over the remaining link. Owner node is locked.
1647  */
1648 void tipc_link_failover_send_queue(struct tipc_link *l_ptr)
1649 {
1650         int msgcount;
1651         struct tipc_link *tunnel = l_ptr->owner->active_links[0];
1652         struct tipc_msg tunnel_hdr;
1653         struct sk_buff *skb;
1654         int split_bundles;
1655
1656         if (!tunnel)
1657                 return;
1658
1659         tipc_msg_init(link_own_addr(l_ptr), &tunnel_hdr, CHANGEOVER_PROTOCOL,
1660                       ORIGINAL_MSG, INT_H_SIZE, l_ptr->addr);
1661         skb_queue_splice_tail_init(&l_ptr->backlogq, &l_ptr->transmq);
1662         tipc_link_purge_backlog(l_ptr);
1663         msgcount = skb_queue_len(&l_ptr->transmq);
1664         msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
1665         msg_set_msgcnt(&tunnel_hdr, msgcount);
1666
1667         if (skb_queue_empty(&l_ptr->transmq)) {
1668                 skb = tipc_buf_acquire(INT_H_SIZE);
1669                 if (skb) {
1670                         skb_copy_to_linear_data(skb, &tunnel_hdr, INT_H_SIZE);
1671                         msg_set_size(&tunnel_hdr, INT_H_SIZE);
1672                         __tipc_link_xmit_skb(tunnel, skb);
1673                 } else {
1674                         pr_warn("%sunable to send changeover msg\n",
1675                                 link_co_err);
1676                 }
1677                 return;
1678         }
1679
1680         split_bundles = (l_ptr->owner->active_links[0] !=
1681                          l_ptr->owner->active_links[1]);
1682
1683         skb_queue_walk(&l_ptr->transmq, skb) {
1684                 struct tipc_msg *msg = buf_msg(skb);
1685
1686                 if ((msg_user(msg) == MSG_BUNDLER) && split_bundles) {
1687                         struct tipc_msg *m = msg_get_wrapped(msg);
1688                         unchar *pos = (unchar *)m;
1689
1690                         msgcount = msg_msgcnt(msg);
1691                         while (msgcount--) {
1692                                 msg_set_seqno(m, msg_seqno(msg));
1693                                 tipc_link_tunnel_xmit(l_ptr, &tunnel_hdr, m,
1694                                                       msg_link_selector(m));
1695                                 pos += align(msg_size(m));
1696                                 m = (struct tipc_msg *)pos;
1697                         }
1698                 } else {
1699                         tipc_link_tunnel_xmit(l_ptr, &tunnel_hdr, msg,
1700                                               msg_link_selector(msg));
1701                 }
1702         }
1703 }
1704
1705 /* tipc_link_dup_queue_xmit(): A second link has become active. Tunnel a
1706  * duplicate of the first link's send queue via the new link. This way, we
1707  * are guaranteed that currently queued packets from a socket are delivered
1708  * before future traffic from the same socket, even if this is using the
1709  * new link. The last arriving copy of each duplicate packet is dropped at
1710  * the receiving end by the regular protocol check, so packet cardinality
1711  * and sequence order is preserved per sender/receiver socket pair.
1712  * Owner node is locked.
1713  */
1714 void tipc_link_dup_queue_xmit(struct tipc_link *link,
1715                               struct tipc_link *tnl)
1716 {
1717         struct sk_buff *skb;
1718         struct tipc_msg tnl_hdr;
1719         struct sk_buff_head *queue = &link->transmq;
1720         int mcnt;
1721
1722         tipc_msg_init(link_own_addr(link), &tnl_hdr, CHANGEOVER_PROTOCOL,
1723                       DUPLICATE_MSG, INT_H_SIZE, link->addr);
1724         mcnt = skb_queue_len(&link->transmq) + skb_queue_len(&link->backlogq);
1725         msg_set_msgcnt(&tnl_hdr, mcnt);
1726         msg_set_bearer_id(&tnl_hdr, link->peer_bearer_id);
1727
1728 tunnel_queue:
1729         skb_queue_walk(queue, skb) {
1730                 struct sk_buff *outskb;
1731                 struct tipc_msg *msg = buf_msg(skb);
1732                 u32 len = msg_size(msg);
1733
1734                 msg_set_ack(msg, mod(link->next_in_no - 1));
1735                 msg_set_bcast_ack(msg, link->owner->bclink.last_in);
1736                 msg_set_size(&tnl_hdr, len + INT_H_SIZE);
1737                 outskb = tipc_buf_acquire(len + INT_H_SIZE);
1738                 if (outskb == NULL) {
1739                         pr_warn("%sunable to send duplicate msg\n",
1740                                 link_co_err);
1741                         return;
1742                 }
1743                 skb_copy_to_linear_data(outskb, &tnl_hdr, INT_H_SIZE);
1744                 skb_copy_to_linear_data_offset(outskb, INT_H_SIZE,
1745                                                skb->data, len);
1746                 __tipc_link_xmit_skb(tnl, outskb);
1747                 if (!tipc_link_is_up(link))
1748                         return;
1749         }
1750         if (queue == &link->backlogq)
1751                 return;
1752         queue = &link->backlogq;
1753         goto tunnel_queue;
1754 }
1755
1756 /* tipc_link_dup_rcv(): Receive a tunnelled DUPLICATE_MSG packet.
1757  * Owner node is locked.
1758  */
1759 static void tipc_link_dup_rcv(struct tipc_link *link,
1760                               struct sk_buff *skb)
1761 {
1762         struct sk_buff *iskb;
1763         int pos = 0;
1764
1765         if (!tipc_link_is_up(link))
1766                 return;
1767
1768         if (!tipc_msg_extract(skb, &iskb, &pos)) {
1769                 pr_warn("%sfailed to extract inner dup pkt\n", link_co_err);
1770                 return;
1771         }
1772         /* Append buffer to deferred queue, if applicable: */
1773         link_handle_out_of_seq_msg(link, iskb);
1774 }
1775
1776 /*  tipc_link_failover_rcv(): Receive a tunnelled ORIGINAL_MSG packet
1777  *  Owner node is locked.
1778  */
1779 static struct sk_buff *tipc_link_failover_rcv(struct tipc_link *l_ptr,
1780                                               struct sk_buff *t_buf)
1781 {
1782         struct tipc_msg *t_msg = buf_msg(t_buf);
1783         struct sk_buff *buf = NULL;
1784         struct tipc_msg *msg;
1785         int pos = 0;
1786
1787         if (tipc_link_is_up(l_ptr))
1788                 tipc_link_reset(l_ptr);
1789
1790         /* First failover packet? */
1791         if (l_ptr->exp_msg_count == START_CHANGEOVER)
1792                 l_ptr->exp_msg_count = msg_msgcnt(t_msg);
1793
1794         /* Should there be an inner packet? */
1795         if (l_ptr->exp_msg_count) {
1796                 l_ptr->exp_msg_count--;
1797                 if (!tipc_msg_extract(t_buf, &buf, &pos)) {
1798                         pr_warn("%sno inner failover pkt\n", link_co_err);
1799                         goto exit;
1800                 }
1801                 msg = buf_msg(buf);
1802
1803                 if (less(msg_seqno(msg), l_ptr->reset_checkpoint)) {
1804                         kfree_skb(buf);
1805                         buf = NULL;
1806                         goto exit;
1807                 }
1808                 if (msg_user(msg) == MSG_FRAGMENTER) {
1809                         l_ptr->stats.recv_fragments++;
1810                         tipc_buf_append(&l_ptr->reasm_buf, &buf);
1811                 }
1812         }
1813 exit:
1814         if ((!l_ptr->exp_msg_count) && (l_ptr->flags & LINK_STOPPED))
1815                 tipc_link_delete(l_ptr);
1816         return buf;
1817 }
1818
1819 /*  tipc_link_tunnel_rcv(): Receive a tunnelled packet, sent
1820  *  via other link as result of a failover (ORIGINAL_MSG) or
1821  *  a new active link (DUPLICATE_MSG). Failover packets are
1822  *  returned to the active link for delivery upwards.
1823  *  Owner node is locked.
1824  */
1825 static int tipc_link_tunnel_rcv(struct tipc_node *n_ptr,
1826                                 struct sk_buff **buf)
1827 {
1828         struct sk_buff *t_buf = *buf;
1829         struct tipc_link *l_ptr;
1830         struct tipc_msg *t_msg = buf_msg(t_buf);
1831         u32 bearer_id = msg_bearer_id(t_msg);
1832
1833         *buf = NULL;
1834
1835         if (bearer_id >= MAX_BEARERS)
1836                 goto exit;
1837
1838         l_ptr = n_ptr->links[bearer_id];
1839         if (!l_ptr)
1840                 goto exit;
1841
1842         if (msg_type(t_msg) == DUPLICATE_MSG)
1843                 tipc_link_dup_rcv(l_ptr, t_buf);
1844         else if (msg_type(t_msg) == ORIGINAL_MSG)
1845                 *buf = tipc_link_failover_rcv(l_ptr, t_buf);
1846         else
1847                 pr_warn("%sunknown tunnel pkt received\n", link_co_err);
1848 exit:
1849         kfree_skb(t_buf);
1850         return *buf != NULL;
1851 }
1852
1853 static void link_set_supervision_props(struct tipc_link *l_ptr, u32 tol)
1854 {
1855         unsigned long intv = ((tol / 4) > 500) ? 500 : tol / 4;
1856
1857         if ((tol < TIPC_MIN_LINK_TOL) || (tol > TIPC_MAX_LINK_TOL))
1858                 return;
1859
1860         l_ptr->tolerance = tol;
1861         l_ptr->cont_intv = msecs_to_jiffies(intv);
1862         l_ptr->abort_limit = tol / (jiffies_to_msecs(l_ptr->cont_intv) / 4);
1863 }
1864
1865 void tipc_link_set_queue_limits(struct tipc_link *l, u32 win)
1866 {
1867         int max_bulk = TIPC_MAX_PUBLICATIONS / (l->max_pkt / ITEM_SIZE);
1868
1869         l->window = win;
1870         l->backlog[TIPC_LOW_IMPORTANCE].limit      = win / 2;
1871         l->backlog[TIPC_MEDIUM_IMPORTANCE].limit   = win;
1872         l->backlog[TIPC_HIGH_IMPORTANCE].limit     = win / 2 * 3;
1873         l->backlog[TIPC_CRITICAL_IMPORTANCE].limit = win * 2;
1874         l->backlog[TIPC_SYSTEM_IMPORTANCE].limit   = max_bulk;
1875 }
1876
1877 /* tipc_link_find_owner - locate owner node of link by link's name
1878  * @net: the applicable net namespace
1879  * @name: pointer to link name string
1880  * @bearer_id: pointer to index in 'node->links' array where the link was found.
1881  *
1882  * Returns pointer to node owning the link, or 0 if no matching link is found.
1883  */
1884 static struct tipc_node *tipc_link_find_owner(struct net *net,
1885                                               const char *link_name,
1886                                               unsigned int *bearer_id)
1887 {
1888         struct tipc_net *tn = net_generic(net, tipc_net_id);
1889         struct tipc_link *l_ptr;
1890         struct tipc_node *n_ptr;
1891         struct tipc_node *found_node = NULL;
1892         int i;
1893
1894         *bearer_id = 0;
1895         rcu_read_lock();
1896         list_for_each_entry_rcu(n_ptr, &tn->node_list, list) {
1897                 tipc_node_lock(n_ptr);
1898                 for (i = 0; i < MAX_BEARERS; i++) {
1899                         l_ptr = n_ptr->links[i];
1900                         if (l_ptr && !strcmp(l_ptr->name, link_name)) {
1901                                 *bearer_id = i;
1902                                 found_node = n_ptr;
1903                                 break;
1904                         }
1905                 }
1906                 tipc_node_unlock(n_ptr);
1907                 if (found_node)
1908                         break;
1909         }
1910         rcu_read_unlock();
1911
1912         return found_node;
1913 }
1914
1915 /**
1916  * link_reset_statistics - reset link statistics
1917  * @l_ptr: pointer to link
1918  */
1919 static void link_reset_statistics(struct tipc_link *l_ptr)
1920 {
1921         memset(&l_ptr->stats, 0, sizeof(l_ptr->stats));
1922         l_ptr->stats.sent_info = l_ptr->next_out_no;
1923         l_ptr->stats.recv_info = l_ptr->next_in_no;
1924 }
1925
1926 static void link_print(struct tipc_link *l_ptr, const char *str)
1927 {
1928         struct tipc_net *tn = net_generic(l_ptr->owner->net, tipc_net_id);
1929         struct tipc_bearer *b_ptr;
1930
1931         rcu_read_lock();
1932         b_ptr = rcu_dereference_rtnl(tn->bearer_list[l_ptr->bearer_id]);
1933         if (b_ptr)
1934                 pr_info("%s Link %x<%s>:", str, l_ptr->addr, b_ptr->name);
1935         rcu_read_unlock();
1936
1937         if (link_working_unknown(l_ptr))
1938                 pr_cont(":WU\n");
1939         else if (link_reset_reset(l_ptr))
1940                 pr_cont(":RR\n");
1941         else if (link_reset_unknown(l_ptr))
1942                 pr_cont(":RU\n");
1943         else if (link_working_working(l_ptr))
1944                 pr_cont(":WW\n");
1945         else
1946                 pr_cont("\n");
1947 }
1948
1949 /* Parse and validate nested (link) properties valid for media, bearer and link
1950  */
1951 int tipc_nl_parse_link_prop(struct nlattr *prop, struct nlattr *props[])
1952 {
1953         int err;
1954
1955         err = nla_parse_nested(props, TIPC_NLA_PROP_MAX, prop,
1956                                tipc_nl_prop_policy);
1957         if (err)
1958                 return err;
1959
1960         if (props[TIPC_NLA_PROP_PRIO]) {
1961                 u32 prio;
1962
1963                 prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
1964                 if (prio > TIPC_MAX_LINK_PRI)
1965                         return -EINVAL;
1966         }
1967
1968         if (props[TIPC_NLA_PROP_TOL]) {
1969                 u32 tol;
1970
1971                 tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
1972                 if ((tol < TIPC_MIN_LINK_TOL) || (tol > TIPC_MAX_LINK_TOL))
1973                         return -EINVAL;
1974         }
1975
1976         if (props[TIPC_NLA_PROP_WIN]) {
1977                 u32 win;
1978
1979                 win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
1980                 if ((win < TIPC_MIN_LINK_WIN) || (win > TIPC_MAX_LINK_WIN))
1981                         return -EINVAL;
1982         }
1983
1984         return 0;
1985 }
1986
1987 int tipc_nl_link_set(struct sk_buff *skb, struct genl_info *info)
1988 {
1989         int err;
1990         int res = 0;
1991         int bearer_id;
1992         char *name;
1993         struct tipc_link *link;
1994         struct tipc_node *node;
1995         struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
1996         struct net *net = sock_net(skb->sk);
1997
1998         if (!info->attrs[TIPC_NLA_LINK])
1999                 return -EINVAL;
2000
2001         err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
2002                                info->attrs[TIPC_NLA_LINK],
2003                                tipc_nl_link_policy);
2004         if (err)
2005                 return err;
2006
2007         if (!attrs[TIPC_NLA_LINK_NAME])
2008                 return -EINVAL;
2009
2010         name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
2011
2012         node = tipc_link_find_owner(net, name, &bearer_id);
2013         if (!node)
2014                 return -EINVAL;
2015
2016         tipc_node_lock(node);
2017
2018         link = node->links[bearer_id];
2019         if (!link) {
2020                 res = -EINVAL;
2021                 goto out;
2022         }
2023
2024         if (attrs[TIPC_NLA_LINK_PROP]) {
2025                 struct nlattr *props[TIPC_NLA_PROP_MAX + 1];
2026
2027                 err = tipc_nl_parse_link_prop(attrs[TIPC_NLA_LINK_PROP],
2028                                               props);
2029                 if (err) {
2030                         res = err;
2031                         goto out;
2032                 }
2033
2034                 if (props[TIPC_NLA_PROP_TOL]) {
2035                         u32 tol;
2036
2037                         tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
2038                         link_set_supervision_props(link, tol);
2039                         tipc_link_proto_xmit(link, STATE_MSG, 0, 0, tol, 0, 0);
2040                 }
2041                 if (props[TIPC_NLA_PROP_PRIO]) {
2042                         u32 prio;
2043
2044                         prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
2045                         link->priority = prio;
2046                         tipc_link_proto_xmit(link, STATE_MSG, 0, 0, 0, prio, 0);
2047                 }
2048                 if (props[TIPC_NLA_PROP_WIN]) {
2049                         u32 win;
2050
2051                         win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
2052                         tipc_link_set_queue_limits(link, win);
2053                 }
2054         }
2055
2056 out:
2057         tipc_node_unlock(node);
2058
2059         return res;
2060 }
2061
2062 static int __tipc_nl_add_stats(struct sk_buff *skb, struct tipc_stats *s)
2063 {
2064         int i;
2065         struct nlattr *stats;
2066
2067         struct nla_map {
2068                 u32 key;
2069                 u32 val;
2070         };
2071
2072         struct nla_map map[] = {
2073                 {TIPC_NLA_STATS_RX_INFO, s->recv_info},
2074                 {TIPC_NLA_STATS_RX_FRAGMENTS, s->recv_fragments},
2075                 {TIPC_NLA_STATS_RX_FRAGMENTED, s->recv_fragmented},
2076                 {TIPC_NLA_STATS_RX_BUNDLES, s->recv_bundles},
2077                 {TIPC_NLA_STATS_RX_BUNDLED, s->recv_bundled},
2078                 {TIPC_NLA_STATS_TX_INFO, s->sent_info},
2079                 {TIPC_NLA_STATS_TX_FRAGMENTS, s->sent_fragments},
2080                 {TIPC_NLA_STATS_TX_FRAGMENTED, s->sent_fragmented},
2081                 {TIPC_NLA_STATS_TX_BUNDLES, s->sent_bundles},
2082                 {TIPC_NLA_STATS_TX_BUNDLED, s->sent_bundled},
2083                 {TIPC_NLA_STATS_MSG_PROF_TOT, (s->msg_length_counts) ?
2084                         s->msg_length_counts : 1},
2085                 {TIPC_NLA_STATS_MSG_LEN_CNT, s->msg_length_counts},
2086                 {TIPC_NLA_STATS_MSG_LEN_TOT, s->msg_lengths_total},
2087                 {TIPC_NLA_STATS_MSG_LEN_P0, s->msg_length_profile[0]},
2088                 {TIPC_NLA_STATS_MSG_LEN_P1, s->msg_length_profile[1]},
2089                 {TIPC_NLA_STATS_MSG_LEN_P2, s->msg_length_profile[2]},
2090                 {TIPC_NLA_STATS_MSG_LEN_P3, s->msg_length_profile[3]},
2091                 {TIPC_NLA_STATS_MSG_LEN_P4, s->msg_length_profile[4]},
2092                 {TIPC_NLA_STATS_MSG_LEN_P5, s->msg_length_profile[5]},
2093                 {TIPC_NLA_STATS_MSG_LEN_P6, s->msg_length_profile[6]},
2094                 {TIPC_NLA_STATS_RX_STATES, s->recv_states},
2095                 {TIPC_NLA_STATS_RX_PROBES, s->recv_probes},
2096                 {TIPC_NLA_STATS_RX_NACKS, s->recv_nacks},
2097                 {TIPC_NLA_STATS_RX_DEFERRED, s->deferred_recv},
2098                 {TIPC_NLA_STATS_TX_STATES, s->sent_states},
2099                 {TIPC_NLA_STATS_TX_PROBES, s->sent_probes},
2100                 {TIPC_NLA_STATS_TX_NACKS, s->sent_nacks},
2101                 {TIPC_NLA_STATS_TX_ACKS, s->sent_acks},
2102                 {TIPC_NLA_STATS_RETRANSMITTED, s->retransmitted},
2103                 {TIPC_NLA_STATS_DUPLICATES, s->duplicates},
2104                 {TIPC_NLA_STATS_LINK_CONGS, s->link_congs},
2105                 {TIPC_NLA_STATS_MAX_QUEUE, s->max_queue_sz},
2106                 {TIPC_NLA_STATS_AVG_QUEUE, s->queue_sz_counts ?
2107                         (s->accu_queue_sz / s->queue_sz_counts) : 0}
2108         };
2109
2110         stats = nla_nest_start(skb, TIPC_NLA_LINK_STATS);
2111         if (!stats)
2112                 return -EMSGSIZE;
2113
2114         for (i = 0; i <  ARRAY_SIZE(map); i++)
2115                 if (nla_put_u32(skb, map[i].key, map[i].val))
2116                         goto msg_full;
2117
2118         nla_nest_end(skb, stats);
2119
2120         return 0;
2121 msg_full:
2122         nla_nest_cancel(skb, stats);
2123
2124         return -EMSGSIZE;
2125 }
2126
2127 /* Caller should hold appropriate locks to protect the link */
2128 static int __tipc_nl_add_link(struct net *net, struct tipc_nl_msg *msg,
2129                               struct tipc_link *link)
2130 {
2131         int err;
2132         void *hdr;
2133         struct nlattr *attrs;
2134         struct nlattr *prop;
2135         struct tipc_net *tn = net_generic(net, tipc_net_id);
2136
2137         hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
2138                           NLM_F_MULTI, TIPC_NL_LINK_GET);
2139         if (!hdr)
2140                 return -EMSGSIZE;
2141
2142         attrs = nla_nest_start(msg->skb, TIPC_NLA_LINK);
2143         if (!attrs)
2144                 goto msg_full;
2145
2146         if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, link->name))
2147                 goto attr_msg_full;
2148         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_DEST,
2149                         tipc_cluster_mask(tn->own_addr)))
2150                 goto attr_msg_full;
2151         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_MTU, link->max_pkt))
2152                 goto attr_msg_full;
2153         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, link->next_in_no))
2154                 goto attr_msg_full;
2155         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, link->next_out_no))
2156                 goto attr_msg_full;
2157
2158         if (tipc_link_is_up(link))
2159                 if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
2160                         goto attr_msg_full;
2161         if (tipc_link_is_active(link))
2162                 if (nla_put_flag(msg->skb, TIPC_NLA_LINK_ACTIVE))
2163                         goto attr_msg_full;
2164
2165         prop = nla_nest_start(msg->skb, TIPC_NLA_LINK_PROP);
2166         if (!prop)
2167                 goto attr_msg_full;
2168         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
2169                 goto prop_msg_full;
2170         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_TOL, link->tolerance))
2171                 goto prop_msg_full;
2172         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN,
2173                         link->window))
2174                 goto prop_msg_full;
2175         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
2176                 goto prop_msg_full;
2177         nla_nest_end(msg->skb, prop);
2178
2179         err = __tipc_nl_add_stats(msg->skb, &link->stats);
2180         if (err)
2181                 goto attr_msg_full;
2182
2183         nla_nest_end(msg->skb, attrs);
2184         genlmsg_end(msg->skb, hdr);
2185
2186         return 0;
2187
2188 prop_msg_full:
2189         nla_nest_cancel(msg->skb, prop);
2190 attr_msg_full:
2191         nla_nest_cancel(msg->skb, attrs);
2192 msg_full:
2193         genlmsg_cancel(msg->skb, hdr);
2194
2195         return -EMSGSIZE;
2196 }
2197
2198 /* Caller should hold node lock  */
2199 static int __tipc_nl_add_node_links(struct net *net, struct tipc_nl_msg *msg,
2200                                     struct tipc_node *node, u32 *prev_link)
2201 {
2202         u32 i;
2203         int err;
2204
2205         for (i = *prev_link; i < MAX_BEARERS; i++) {
2206                 *prev_link = i;
2207
2208                 if (!node->links[i])
2209                         continue;
2210
2211                 err = __tipc_nl_add_link(net, msg, node->links[i]);
2212                 if (err)
2213                         return err;
2214         }
2215         *prev_link = 0;
2216
2217         return 0;
2218 }
2219
2220 int tipc_nl_link_dump(struct sk_buff *skb, struct netlink_callback *cb)
2221 {
2222         struct net *net = sock_net(skb->sk);
2223         struct tipc_net *tn = net_generic(net, tipc_net_id);
2224         struct tipc_node *node;
2225         struct tipc_nl_msg msg;
2226         u32 prev_node = cb->args[0];
2227         u32 prev_link = cb->args[1];
2228         int done = cb->args[2];
2229         int err;
2230
2231         if (done)
2232                 return 0;
2233
2234         msg.skb = skb;
2235         msg.portid = NETLINK_CB(cb->skb).portid;
2236         msg.seq = cb->nlh->nlmsg_seq;
2237
2238         rcu_read_lock();
2239
2240         if (prev_node) {
2241                 node = tipc_node_find(net, prev_node);
2242                 if (!node) {
2243                         /* We never set seq or call nl_dump_check_consistent()
2244                          * this means that setting prev_seq here will cause the
2245                          * consistence check to fail in the netlink callback
2246                          * handler. Resulting in the last NLMSG_DONE message
2247                          * having the NLM_F_DUMP_INTR flag set.
2248                          */
2249                         cb->prev_seq = 1;
2250                         goto out;
2251                 }
2252
2253                 list_for_each_entry_continue_rcu(node, &tn->node_list,
2254                                                  list) {
2255                         tipc_node_lock(node);
2256                         err = __tipc_nl_add_node_links(net, &msg, node,
2257                                                        &prev_link);
2258                         tipc_node_unlock(node);
2259                         if (err)
2260                                 goto out;
2261
2262                         prev_node = node->addr;
2263                 }
2264         } else {
2265                 err = tipc_nl_add_bc_link(net, &msg);
2266                 if (err)
2267                         goto out;
2268
2269                 list_for_each_entry_rcu(node, &tn->node_list, list) {
2270                         tipc_node_lock(node);
2271                         err = __tipc_nl_add_node_links(net, &msg, node,
2272                                                        &prev_link);
2273                         tipc_node_unlock(node);
2274                         if (err)
2275                                 goto out;
2276
2277                         prev_node = node->addr;
2278                 }
2279         }
2280         done = 1;
2281 out:
2282         rcu_read_unlock();
2283
2284         cb->args[0] = prev_node;
2285         cb->args[1] = prev_link;
2286         cb->args[2] = done;
2287
2288         return skb->len;
2289 }
2290
2291 int tipc_nl_link_get(struct sk_buff *skb, struct genl_info *info)
2292 {
2293         struct net *net = genl_info_net(info);
2294         struct sk_buff *ans_skb;
2295         struct tipc_nl_msg msg;
2296         struct tipc_link *link;
2297         struct tipc_node *node;
2298         char *name;
2299         int bearer_id;
2300         int err;
2301
2302         if (!info->attrs[TIPC_NLA_LINK_NAME])
2303                 return -EINVAL;
2304
2305         name = nla_data(info->attrs[TIPC_NLA_LINK_NAME]);
2306         node = tipc_link_find_owner(net, name, &bearer_id);
2307         if (!node)
2308                 return -EINVAL;
2309
2310         ans_skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
2311         if (!ans_skb)
2312                 return -ENOMEM;
2313
2314         msg.skb = ans_skb;
2315         msg.portid = info->snd_portid;
2316         msg.seq = info->snd_seq;
2317
2318         tipc_node_lock(node);
2319         link = node->links[bearer_id];
2320         if (!link) {
2321                 err = -EINVAL;
2322                 goto err_out;
2323         }
2324
2325         err = __tipc_nl_add_link(net, &msg, link);
2326         if (err)
2327                 goto err_out;
2328
2329         tipc_node_unlock(node);
2330
2331         return genlmsg_reply(ans_skb, info);
2332
2333 err_out:
2334         tipc_node_unlock(node);
2335         nlmsg_free(ans_skb);
2336
2337         return err;
2338 }
2339
2340 int tipc_nl_link_reset_stats(struct sk_buff *skb, struct genl_info *info)
2341 {
2342         int err;
2343         char *link_name;
2344         unsigned int bearer_id;
2345         struct tipc_link *link;
2346         struct tipc_node *node;
2347         struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
2348         struct net *net = sock_net(skb->sk);
2349
2350         if (!info->attrs[TIPC_NLA_LINK])
2351                 return -EINVAL;
2352
2353         err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
2354                                info->attrs[TIPC_NLA_LINK],
2355                                tipc_nl_link_policy);
2356         if (err)
2357                 return err;
2358
2359         if (!attrs[TIPC_NLA_LINK_NAME])
2360                 return -EINVAL;
2361
2362         link_name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
2363
2364         if (strcmp(link_name, tipc_bclink_name) == 0) {
2365                 err = tipc_bclink_reset_stats(net);
2366                 if (err)
2367                         return err;
2368                 return 0;
2369         }
2370
2371         node = tipc_link_find_owner(net, link_name, &bearer_id);
2372         if (!node)
2373                 return -EINVAL;
2374
2375         tipc_node_lock(node);
2376
2377         link = node->links[bearer_id];
2378         if (!link) {
2379                 tipc_node_unlock(node);
2380                 return -EINVAL;
2381         }
2382
2383         link_reset_statistics(link);
2384
2385         tipc_node_unlock(node);
2386
2387         return 0;
2388 }