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                 tipc_node_lock(n_ptr);
 984
 985                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 986                 pr_info("Broadcast link info for %s\n", addr_string);
 987                 pr_info("Reception permitted: %d,  Acked: %u\n",
 988                         n_ptr->bclink.recv_permitted,
 989                         n_ptr->bclink.acked);
 990                 pr_info("Last in: %u,  Oos state: %u,  Last sent: %u\n",
 991                         n_ptr->bclink.last_in,
 992                         n_ptr->bclink.oos_state,
 993                         n_ptr->bclink.last_sent);
 994
 995                 tipc_node_unlock(n_ptr);
 996
 997                 tipc_bclink_set_flags(net, TIPC_BCLINK_RESET);
 998                 l_ptr->stale_count = 0;
 999         }
1000 }
1001
1002 void tipc_link_retransmit(struct tipc_link *l_ptr, struct sk_buff *skb,
1003                           u32 retransmits)
1004 {
1005         struct tipc_msg *msg;
1006
1007         if (!skb)
1008                 return;
1009
1010         msg = buf_msg(skb);
1011
1012         /* Detect repeated retransmit failures */
1013         if (l_ptr->last_retransmitted == msg_seqno(msg)) {
1014                 if (++l_ptr->stale_count > 100) {
1015                         link_retransmit_failure(l_ptr, skb);
1016                         return;
1017                 }
1018         } else {
1019                 l_ptr->last_retransmitted = msg_seqno(msg);
1020                 l_ptr->stale_count = 1;
1021         }
1022
1023         skb_queue_walk_from(&l_ptr->transmq, skb) {
1024                 if (!retransmits)
1025                         break;
1026                 msg = buf_msg(skb);
1027                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1028                 msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1029                 tipc_bearer_send(l_ptr->owner->net, l_ptr->bearer_id, skb,
1030                                  &l_ptr->media_addr);
1031                 retransmits--;
1032                 l_ptr->stats.retransmitted++;
1033         }
1034 }
1035
1036 /* link_synch(): check if all packets arrived before the synch
1037  *               point have been consumed
1038  * Returns true if the parallel links are synched, otherwise false
1039  */
1040 static bool link_synch(struct tipc_link *l)
1041 {
1042         unsigned int post_synch;
1043         struct tipc_link *pl;
1044
1045         pl  = tipc_parallel_link(l);
1046         if (pl == l)
1047                 goto synched;
1048
1049         /* Was last pre-synch packet added to input queue ? */
1050         if (less_eq(pl->next_in_no, l->synch_point))
1051                 return false;
1052
1053         /* Is it still in the input queue ? */
1054         post_synch = mod(pl->next_in_no - l->synch_point) - 1;
1055         if (skb_queue_len(&pl->inputq) > post_synch)
1056                 return false;
1057 synched:
1058         l->flags &= ~LINK_SYNCHING;
1059         return true;
1060 }
1061
1062 static void link_retrieve_defq(struct tipc_link *link,
1063                                struct sk_buff_head *list)
1064 {
1065         u32 seq_no;
1066
1067         if (skb_queue_empty(&link->deferdq))
1068                 return;
1069
1070         seq_no = buf_seqno(skb_peek(&link->deferdq));
1071         if (seq_no == mod(link->next_in_no))
1072                 skb_queue_splice_tail_init(&link->deferdq, list);
1073 }
1074
1075 /**
1076  * tipc_rcv - process TIPC packets/messages arriving from off-node
1077  * @net: the applicable net namespace
1078  * @skb: TIPC packet
1079  * @b_ptr: pointer to bearer message arrived on
1080  *
1081  * Invoked with no locks held.  Bearer pointer must point to a valid bearer
1082  * structure (i.e. cannot be NULL), but bearer can be inactive.
1083  */
1084 void tipc_rcv(struct net *net, struct sk_buff *skb, struct tipc_bearer *b_ptr)
1085 {
1086         struct tipc_net *tn = net_generic(net, tipc_net_id);
1087         struct sk_buff_head head;
1088         struct tipc_node *n_ptr;
1089         struct tipc_link *l_ptr;
1090         struct sk_buff *skb1, *tmp;
1091         struct tipc_msg *msg;
1092         u32 seq_no;
1093         u32 ackd;
1094         u32 released;
1095
1096         skb2list(skb, &head);
1097
1098         while ((skb = __skb_dequeue(&head))) {
1099                 /* Ensure message is well-formed */
1100                 if (unlikely(!tipc_msg_validate(skb)))
1101                         goto discard;
1102
1103                 /* Handle arrival of a non-unicast link message */
1104                 msg = buf_msg(skb);
1105                 if (unlikely(msg_non_seq(msg))) {
1106                         if (msg_user(msg) ==  LINK_CONFIG)
1107                                 tipc_disc_rcv(net, skb, b_ptr);
1108                         else
1109                                 tipc_bclink_rcv(net, skb);
1110                         continue;
1111                 }
1112
1113                 /* Discard unicast link messages destined for another node */
1114                 if (unlikely(!msg_short(msg) &&
1115                              (msg_destnode(msg) != tn->own_addr)))
1116                         goto discard;
1117
1118                 /* Locate neighboring node that sent message */
1119                 n_ptr = tipc_node_find(net, msg_prevnode(msg));
1120                 if (unlikely(!n_ptr))
1121                         goto discard;
1122                 tipc_node_lock(n_ptr);
1123
1124                 /* Locate unicast link endpoint that should handle message */
1125                 l_ptr = n_ptr->links[b_ptr->identity];
1126                 if (unlikely(!l_ptr))
1127                         goto unlock;
1128
1129                 /* Verify that communication with node is currently allowed */
1130                 if ((n_ptr->action_flags & TIPC_WAIT_PEER_LINKS_DOWN) &&
1131                     msg_user(msg) == LINK_PROTOCOL &&
1132                     (msg_type(msg) == RESET_MSG ||
1133                     msg_type(msg) == ACTIVATE_MSG) &&
1134                     !msg_redundant_link(msg))
1135                         n_ptr->action_flags &= ~TIPC_WAIT_PEER_LINKS_DOWN;
1136
1137                 if (tipc_node_blocked(n_ptr))
1138                         goto unlock;
1139
1140                 /* Validate message sequence number info */
1141                 seq_no = msg_seqno(msg);
1142                 ackd = msg_ack(msg);
1143
1144                 /* Release acked messages */
1145                 if (unlikely(n_ptr->bclink.acked != msg_bcast_ack(msg)))
1146                         tipc_bclink_acknowledge(n_ptr, msg_bcast_ack(msg));
1147
1148                 released = 0;
1149                 skb_queue_walk_safe(&l_ptr->transmq, skb1, tmp) {
1150                         if (more(buf_seqno(skb1), ackd))
1151                                 break;
1152                          __skb_unlink(skb1, &l_ptr->transmq);
1153                          kfree_skb(skb1);
1154                          released = 1;
1155                 }
1156
1157                 /* Try sending any messages link endpoint has pending */
1158                 if (unlikely(skb_queue_len(&l_ptr->backlogq)))
1159                         tipc_link_push_packets(l_ptr);
1160
1161                 if (released && !skb_queue_empty(&l_ptr->wakeupq))
1162                         link_prepare_wakeup(l_ptr);
1163
1164                 /* Process the incoming packet */
1165                 if (unlikely(!link_working_working(l_ptr))) {
1166                         if (msg_user(msg) == LINK_PROTOCOL) {
1167                                 tipc_link_proto_rcv(l_ptr, skb);
1168                                 link_retrieve_defq(l_ptr, &head);
1169                                 skb = NULL;
1170                                 goto unlock;
1171                         }
1172
1173                         /* Traffic message. Conditionally activate link */
1174                         link_state_event(l_ptr, TRAFFIC_MSG_EVT);
1175
1176                         if (link_working_working(l_ptr)) {
1177                                 /* Re-insert buffer in front of queue */
1178                                 __skb_queue_head(&head, skb);
1179                                 skb = NULL;
1180                                 goto unlock;
1181                         }
1182                         goto unlock;
1183                 }
1184
1185                 /* Link is now in state WORKING_WORKING */
1186                 if (unlikely(seq_no != mod(l_ptr->next_in_no))) {
1187                         link_handle_out_of_seq_msg(l_ptr, skb);
1188                         link_retrieve_defq(l_ptr, &head);
1189                         skb = NULL;
1190                         goto unlock;
1191                 }
1192                 /* Synchronize with parallel link if applicable */
1193                 if (unlikely((l_ptr->flags & LINK_SYNCHING) && !msg_dup(msg))) {
1194                         link_handle_out_of_seq_msg(l_ptr, skb);
1195                         if (link_synch(l_ptr))
1196                                 link_retrieve_defq(l_ptr, &head);
1197                         skb = NULL;
1198                         goto unlock;
1199                 }
1200                 l_ptr->next_in_no++;
1201                 if (unlikely(!skb_queue_empty(&l_ptr->deferdq)))
1202                         link_retrieve_defq(l_ptr, &head);
1203                 if (unlikely(++l_ptr->rcv_unacked >= TIPC_MIN_LINK_WIN)) {
1204                         l_ptr->stats.sent_acks++;
1205                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
1206                 }
1207                 tipc_link_input(l_ptr, skb);
1208                 skb = NULL;
1209 unlock:
1210                 tipc_node_unlock(n_ptr);
1211 discard:
1212                 if (unlikely(skb))
1213                         kfree_skb(skb);
1214         }
1215 }
1216
1217 /* tipc_data_input - deliver data and name distr msgs to upper layer
1218  *
1219  * Consumes buffer if message is of right type
1220  * Node lock must be held
1221  */
1222 static bool tipc_data_input(struct tipc_link *link, struct sk_buff *skb)
1223 {
1224         struct tipc_node *node = link->owner;
1225         struct tipc_msg *msg = buf_msg(skb);
1226         u32 dport = msg_destport(msg);
1227
1228         switch (msg_user(msg)) {
1229         case TIPC_LOW_IMPORTANCE:
1230         case TIPC_MEDIUM_IMPORTANCE:
1231         case TIPC_HIGH_IMPORTANCE:
1232         case TIPC_CRITICAL_IMPORTANCE:
1233         case CONN_MANAGER:
1234                 if (tipc_skb_queue_tail(&link->inputq, skb, dport)) {
1235                         node->inputq = &link->inputq;
1236                         node->action_flags |= TIPC_MSG_EVT;
1237                 }
1238                 return true;
1239         case NAME_DISTRIBUTOR:
1240                 node->bclink.recv_permitted = true;
1241                 node->namedq = &link->namedq;
1242                 skb_queue_tail(&link->namedq, skb);
1243                 if (skb_queue_len(&link->namedq) == 1)
1244                         node->action_flags |= TIPC_NAMED_MSG_EVT;
1245                 return true;
1246         case MSG_BUNDLER:
1247         case CHANGEOVER_PROTOCOL:
1248         case MSG_FRAGMENTER:
1249         case BCAST_PROTOCOL:
1250                 return false;
1251         default:
1252                 pr_warn("Dropping received illegal msg type\n");
1253                 kfree_skb(skb);
1254                 return false;
1255         };
1256 }
1257
1258 /* tipc_link_input - process packet that has passed link protocol check
1259  *
1260  * Consumes buffer
1261  * Node lock must be held
1262  */
1263 static void tipc_link_input(struct tipc_link *link, struct sk_buff *skb)
1264 {
1265         struct tipc_node *node = link->owner;
1266         struct tipc_msg *msg = buf_msg(skb);
1267         struct sk_buff *iskb;
1268         int pos = 0;
1269
1270         if (likely(tipc_data_input(link, skb)))
1271                 return;
1272
1273         switch (msg_user(msg)) {
1274         case CHANGEOVER_PROTOCOL:
1275                 if (msg_dup(msg)) {
1276                         link->flags |= LINK_SYNCHING;
1277                         link->synch_point = msg_seqno(msg_get_wrapped(msg));
1278                 }
1279                 if (!tipc_link_tunnel_rcv(node, &skb))
1280                         break;
1281                 if (msg_user(buf_msg(skb)) != MSG_BUNDLER) {
1282                         tipc_data_input(link, skb);
1283                         break;
1284                 }
1285         case MSG_BUNDLER:
1286                 link->stats.recv_bundles++;
1287                 link->stats.recv_bundled += msg_msgcnt(msg);
1288
1289                 while (tipc_msg_extract(skb, &iskb, &pos))
1290                         tipc_data_input(link, iskb);
1291                 break;
1292         case MSG_FRAGMENTER:
1293                 link->stats.recv_fragments++;
1294                 if (tipc_buf_append(&link->reasm_buf, &skb)) {
1295                         link->stats.recv_fragmented++;
1296                         tipc_data_input(link, skb);
1297                 } else if (!link->reasm_buf) {
1298                         tipc_link_reset(link);
1299                 }
1300                 break;
1301         case BCAST_PROTOCOL:
1302                 tipc_link_sync_rcv(node, skb);
1303                 break;
1304         default:
1305                 break;
1306         };
1307 }
1308
1309 /**
1310  * tipc_link_defer_pkt - Add out-of-sequence message to deferred reception queue
1311  *
1312  * Returns increase in queue length (i.e. 0 or 1)
1313  */
1314 u32 tipc_link_defer_pkt(struct sk_buff_head *list, struct sk_buff *skb)
1315 {
1316         struct sk_buff *skb1;
1317         u32 seq_no = buf_seqno(skb);
1318
1319         /* Empty queue ? */
1320         if (skb_queue_empty(list)) {
1321                 __skb_queue_tail(list, skb);
1322                 return 1;
1323         }
1324
1325         /* Last ? */
1326         if (less(buf_seqno(skb_peek_tail(list)), seq_no)) {
1327                 __skb_queue_tail(list, skb);
1328                 return 1;
1329         }
1330
1331         /* Locate insertion point in queue, then insert; discard if duplicate */
1332         skb_queue_walk(list, skb1) {
1333                 u32 curr_seqno = buf_seqno(skb1);
1334
1335                 if (seq_no == curr_seqno) {
1336                         kfree_skb(skb);
1337                         return 0;
1338                 }
1339
1340                 if (less(seq_no, curr_seqno))
1341                         break;
1342         }
1343
1344         __skb_queue_before(list, skb1, skb);
1345         return 1;
1346 }
1347
1348 /*
1349  * link_handle_out_of_seq_msg - handle arrival of out-of-sequence packet
1350  */
1351 static void link_handle_out_of_seq_msg(struct tipc_link *l_ptr,
1352                                        struct sk_buff *buf)
1353 {
1354         u32 seq_no = buf_seqno(buf);
1355
1356         if (likely(msg_user(buf_msg(buf)) == LINK_PROTOCOL)) {
1357                 tipc_link_proto_rcv(l_ptr, buf);
1358                 return;
1359         }
1360
1361         /* Record OOS packet arrival (force mismatch on next timeout) */
1362         l_ptr->checkpoint--;
1363
1364         /*
1365          * Discard packet if a duplicate; otherwise add it to deferred queue
1366          * and notify peer of gap as per protocol specification
1367          */
1368         if (less(seq_no, mod(l_ptr->next_in_no))) {
1369                 l_ptr->stats.duplicates++;
1370                 kfree_skb(buf);
1371                 return;
1372         }
1373
1374         if (tipc_link_defer_pkt(&l_ptr->deferdq, buf)) {
1375                 l_ptr->stats.deferred_recv++;
1376                 if ((skb_queue_len(&l_ptr->deferdq) % TIPC_MIN_LINK_WIN) == 1)
1377                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
1378         } else {
1379                 l_ptr->stats.duplicates++;
1380         }
1381 }
1382
1383 /*
1384  * Send protocol message to the other endpoint.
1385  */
1386 void tipc_link_proto_xmit(struct tipc_link *l_ptr, u32 msg_typ, int probe_msg,
1387                           u32 gap, u32 tolerance, u32 priority, u32 ack_mtu)
1388 {
1389         struct sk_buff *buf = NULL;
1390         struct tipc_msg *msg = l_ptr->pmsg;
1391         u32 msg_size = sizeof(l_ptr->proto_msg);
1392         int r_flag;
1393
1394         /* Don't send protocol message during link changeover */
1395         if (l_ptr->exp_msg_count)
1396                 return;
1397
1398         /* Abort non-RESET send if communication with node is prohibited */
1399         if ((tipc_node_blocked(l_ptr->owner)) && (msg_typ != RESET_MSG))
1400                 return;
1401
1402         /* Create protocol message with "out-of-sequence" sequence number */
1403         msg_set_type(msg, msg_typ);
1404         msg_set_net_plane(msg, l_ptr->net_plane);
1405         msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1406         msg_set_last_bcast(msg, tipc_bclink_get_last_sent(l_ptr->owner->net));
1407
1408         if (msg_typ == STATE_MSG) {
1409                 u32 next_sent = mod(l_ptr->next_out_no);
1410
1411                 if (!tipc_link_is_up(l_ptr))
1412                         return;
1413                 if (skb_queue_len(&l_ptr->backlogq))
1414                         next_sent = buf_seqno(skb_peek(&l_ptr->backlogq));
1415                 msg_set_next_sent(msg, next_sent);
1416                 if (!skb_queue_empty(&l_ptr->deferdq)) {
1417                         u32 rec = buf_seqno(skb_peek(&l_ptr->deferdq));
1418                         gap = mod(rec - mod(l_ptr->next_in_no));
1419                 }
1420                 msg_set_seq_gap(msg, gap);
1421                 if (gap)
1422                         l_ptr->stats.sent_nacks++;
1423                 msg_set_link_tolerance(msg, tolerance);
1424                 msg_set_linkprio(msg, priority);
1425                 msg_set_max_pkt(msg, ack_mtu);
1426                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1427                 msg_set_probe(msg, probe_msg != 0);
1428                 if (probe_msg) {
1429                         u32 mtu = l_ptr->max_pkt;
1430
1431                         if ((mtu < l_ptr->max_pkt_target) &&
1432                             link_working_working(l_ptr) &&
1433                             l_ptr->fsm_msg_cnt) {
1434                                 msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
1435                                 if (l_ptr->max_pkt_probes == 10) {
1436                                         l_ptr->max_pkt_target = (msg_size - 4);
1437                                         l_ptr->max_pkt_probes = 0;
1438                                         msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
1439                                 }
1440                                 l_ptr->max_pkt_probes++;
1441                         }
1442
1443                         l_ptr->stats.sent_probes++;
1444                 }
1445                 l_ptr->stats.sent_states++;
1446         } else {                /* RESET_MSG or ACTIVATE_MSG */
1447                 msg_set_ack(msg, mod(l_ptr->reset_checkpoint - 1));
1448                 msg_set_seq_gap(msg, 0);
1449                 msg_set_next_sent(msg, 1);
1450                 msg_set_probe(msg, 0);
1451                 msg_set_link_tolerance(msg, l_ptr->tolerance);
1452                 msg_set_linkprio(msg, l_ptr->priority);
1453                 msg_set_max_pkt(msg, l_ptr->max_pkt_target);
1454         }
1455
1456         r_flag = (l_ptr->owner->working_links > tipc_link_is_up(l_ptr));
1457         msg_set_redundant_link(msg, r_flag);
1458         msg_set_linkprio(msg, l_ptr->priority);
1459         msg_set_size(msg, msg_size);
1460
1461         msg_set_seqno(msg, mod(l_ptr->next_out_no + (0xffff/2)));
1462
1463         buf = tipc_buf_acquire(msg_size);
1464         if (!buf)
1465                 return;
1466
1467         skb_copy_to_linear_data(buf, msg, sizeof(l_ptr->proto_msg));
1468         buf->priority = TC_PRIO_CONTROL;
1469         tipc_bearer_send(l_ptr->owner->net, l_ptr->bearer_id, buf,
1470                          &l_ptr->media_addr);
1471         l_ptr->rcv_unacked = 0;
1472         kfree_skb(buf);
1473 }
1474
1475 /*
1476  * Receive protocol message :
1477  * Note that network plane id propagates through the network, and may
1478  * change at any time. The node with lowest address rules
1479  */
1480 static void tipc_link_proto_rcv(struct tipc_link *l_ptr,
1481                                 struct sk_buff *buf)
1482 {
1483         u32 rec_gap = 0;
1484         u32 max_pkt_info;
1485         u32 max_pkt_ack;
1486         u32 msg_tol;
1487         struct tipc_msg *msg = buf_msg(buf);
1488
1489         /* Discard protocol message during link changeover */
1490         if (l_ptr->exp_msg_count)
1491                 goto exit;
1492
1493         if (l_ptr->net_plane != msg_net_plane(msg))
1494                 if (link_own_addr(l_ptr) > msg_prevnode(msg))
1495                         l_ptr->net_plane = msg_net_plane(msg);
1496
1497         switch (msg_type(msg)) {
1498
1499         case RESET_MSG:
1500                 if (!link_working_unknown(l_ptr) &&
1501                     (l_ptr->peer_session != INVALID_SESSION)) {
1502                         if (less_eq(msg_session(msg), l_ptr->peer_session))
1503                                 break; /* duplicate or old reset: ignore */
1504                 }
1505
1506                 if (!msg_redundant_link(msg) && (link_working_working(l_ptr) ||
1507                                 link_working_unknown(l_ptr))) {
1508                         /*
1509                          * peer has lost contact -- don't allow peer's links
1510                          * to reactivate before we recognize loss & clean up
1511                          */
1512                         l_ptr->owner->action_flags |= TIPC_WAIT_OWN_LINKS_DOWN;
1513                 }
1514
1515                 link_state_event(l_ptr, RESET_MSG);
1516
1517                 /* fall thru' */
1518         case ACTIVATE_MSG:
1519                 /* Update link settings according other endpoint's values */
1520                 strcpy((strrchr(l_ptr->name, ':') + 1), (char *)msg_data(msg));
1521
1522                 msg_tol = msg_link_tolerance(msg);
1523                 if (msg_tol > l_ptr->tolerance)
1524                         link_set_supervision_props(l_ptr, msg_tol);
1525
1526                 if (msg_linkprio(msg) > l_ptr->priority)
1527                         l_ptr->priority = msg_linkprio(msg);
1528
1529                 max_pkt_info = msg_max_pkt(msg);
1530                 if (max_pkt_info) {
1531                         if (max_pkt_info < l_ptr->max_pkt_target)
1532                                 l_ptr->max_pkt_target = max_pkt_info;
1533                         if (l_ptr->max_pkt > l_ptr->max_pkt_target)
1534                                 l_ptr->max_pkt = l_ptr->max_pkt_target;
1535                 } else {
1536                         l_ptr->max_pkt = l_ptr->max_pkt_target;
1537                 }
1538
1539                 /* Synchronize broadcast link info, if not done previously */
1540                 if (!tipc_node_is_up(l_ptr->owner)) {
1541                         l_ptr->owner->bclink.last_sent =
1542                                 l_ptr->owner->bclink.last_in =
1543                                 msg_last_bcast(msg);
1544                         l_ptr->owner->bclink.oos_state = 0;
1545                 }
1546
1547                 l_ptr->peer_session = msg_session(msg);
1548                 l_ptr->peer_bearer_id = msg_bearer_id(msg);
1549
1550                 if (msg_type(msg) == ACTIVATE_MSG)
1551                         link_state_event(l_ptr, ACTIVATE_MSG);
1552                 break;
1553         case STATE_MSG:
1554
1555                 msg_tol = msg_link_tolerance(msg);
1556                 if (msg_tol)
1557                         link_set_supervision_props(l_ptr, msg_tol);
1558
1559                 if (msg_linkprio(msg) &&
1560                     (msg_linkprio(msg) != l_ptr->priority)) {
1561                         pr_debug("%s<%s>, priority change %u->%u\n",
1562                                  link_rst_msg, l_ptr->name,
1563                                  l_ptr->priority, msg_linkprio(msg));
1564                         l_ptr->priority = msg_linkprio(msg);
1565                         tipc_link_reset(l_ptr); /* Enforce change to take effect */
1566                         break;
1567                 }
1568
1569                 /* Record reception; force mismatch at next timeout: */
1570                 l_ptr->checkpoint--;
1571
1572                 link_state_event(l_ptr, TRAFFIC_MSG_EVT);
1573                 l_ptr->stats.recv_states++;
1574                 if (link_reset_unknown(l_ptr))
1575                         break;
1576
1577                 if (less_eq(mod(l_ptr->next_in_no), msg_next_sent(msg))) {
1578                         rec_gap = mod(msg_next_sent(msg) -
1579                                       mod(l_ptr->next_in_no));
1580                 }
1581
1582                 max_pkt_ack = msg_max_pkt(msg);
1583                 if (max_pkt_ack > l_ptr->max_pkt) {
1584                         l_ptr->max_pkt = max_pkt_ack;
1585                         l_ptr->max_pkt_probes = 0;
1586                 }
1587
1588                 max_pkt_ack = 0;
1589                 if (msg_probe(msg)) {
1590                         l_ptr->stats.recv_probes++;
1591                         if (msg_size(msg) > sizeof(l_ptr->proto_msg))
1592                                 max_pkt_ack = msg_size(msg);
1593                 }
1594
1595                 /* Protocol message before retransmits, reduce loss risk */
1596                 if (l_ptr->owner->bclink.recv_permitted)
1597                         tipc_bclink_update_link_state(l_ptr->owner,
1598                                                       msg_last_bcast(msg));
1599
1600                 if (rec_gap || (msg_probe(msg))) {
1601                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, rec_gap, 0,
1602                                              0, max_pkt_ack);
1603                 }
1604                 if (msg_seq_gap(msg)) {
1605                         l_ptr->stats.recv_nacks++;
1606                         tipc_link_retransmit(l_ptr, skb_peek(&l_ptr->transmq),
1607                                              msg_seq_gap(msg));
1608                 }
1609                 break;
1610         }
1611 exit:
1612         kfree_skb(buf);
1613 }
1614
1615
1616 /* tipc_link_tunnel_xmit(): Tunnel one packet via a link belonging to
1617  * a different bearer. Owner node is locked.
1618  */
1619 static void tipc_link_tunnel_xmit(struct tipc_link *l_ptr,
1620                                   struct tipc_msg *tunnel_hdr,
1621                                   struct tipc_msg *msg,
1622                                   u32 selector)
1623 {
1624         struct tipc_link *tunnel;
1625         struct sk_buff *skb;
1626         u32 length = msg_size(msg);
1627
1628         tunnel = l_ptr->owner->active_links[selector & 1];
1629         if (!tipc_link_is_up(tunnel)) {
1630                 pr_warn("%stunnel link no longer available\n", link_co_err);
1631                 return;
1632         }
1633         msg_set_size(tunnel_hdr, length + INT_H_SIZE);
1634         skb = tipc_buf_acquire(length + INT_H_SIZE);
1635         if (!skb) {
1636                 pr_warn("%sunable to send tunnel msg\n", link_co_err);
1637                 return;
1638         }
1639         skb_copy_to_linear_data(skb, tunnel_hdr, INT_H_SIZE);
1640         skb_copy_to_linear_data_offset(skb, INT_H_SIZE, msg, length);
1641         __tipc_link_xmit_skb(tunnel, skb);
1642 }
1643
1644
1645 /* tipc_link_failover_send_queue(): A link has gone down, but a second
1646  * link is still active. We can do failover. Tunnel the failing link's
1647  * whole send queue via the remaining link. This way, we don't lose
1648  * any packets, and sequence order is preserved for subsequent traffic
1649  * sent over the remaining link. Owner node is locked.
1650  */
1651 void tipc_link_failover_send_queue(struct tipc_link *l_ptr)
1652 {
1653         int msgcount;
1654         struct tipc_link *tunnel = l_ptr->owner->active_links[0];
1655         struct tipc_msg tunnel_hdr;
1656         struct sk_buff *skb;
1657         int split_bundles;
1658
1659         if (!tunnel)
1660                 return;
1661
1662         tipc_msg_init(link_own_addr(l_ptr), &tunnel_hdr, CHANGEOVER_PROTOCOL,
1663                       ORIGINAL_MSG, INT_H_SIZE, l_ptr->addr);
1664         skb_queue_splice_tail_init(&l_ptr->backlogq, &l_ptr->transmq);
1665         tipc_link_purge_backlog(l_ptr);
1666         msgcount = skb_queue_len(&l_ptr->transmq);
1667         msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
1668         msg_set_msgcnt(&tunnel_hdr, msgcount);
1669
1670         if (skb_queue_empty(&l_ptr->transmq)) {
1671                 skb = tipc_buf_acquire(INT_H_SIZE);
1672                 if (skb) {
1673                         skb_copy_to_linear_data(skb, &tunnel_hdr, INT_H_SIZE);
1674                         msg_set_size(&tunnel_hdr, INT_H_SIZE);
1675                         __tipc_link_xmit_skb(tunnel, skb);
1676                 } else {
1677                         pr_warn("%sunable to send changeover msg\n",
1678                                 link_co_err);
1679                 }
1680                 return;
1681         }
1682
1683         split_bundles = (l_ptr->owner->active_links[0] !=
1684                          l_ptr->owner->active_links[1]);
1685
1686         skb_queue_walk(&l_ptr->transmq, skb) {
1687                 struct tipc_msg *msg = buf_msg(skb);
1688
1689                 if ((msg_user(msg) == MSG_BUNDLER) && split_bundles) {
1690                         struct tipc_msg *m = msg_get_wrapped(msg);
1691                         unchar *pos = (unchar *)m;
1692
1693                         msgcount = msg_msgcnt(msg);
1694                         while (msgcount--) {
1695                                 msg_set_seqno(m, msg_seqno(msg));
1696                                 tipc_link_tunnel_xmit(l_ptr, &tunnel_hdr, m,
1697                                                       msg_link_selector(m));
1698                                 pos += align(msg_size(m));
1699                                 m = (struct tipc_msg *)pos;
1700                         }
1701                 } else {
1702                         tipc_link_tunnel_xmit(l_ptr, &tunnel_hdr, msg,
1703                                               msg_link_selector(msg));
1704                 }
1705         }
1706 }
1707
1708 /* tipc_link_dup_queue_xmit(): A second link has become active. Tunnel a
1709  * duplicate of the first link's send queue via the new link. This way, we
1710  * are guaranteed that currently queued packets from a socket are delivered
1711  * before future traffic from the same socket, even if this is using the
1712  * new link. The last arriving copy of each duplicate packet is dropped at
1713  * the receiving end by the regular protocol check, so packet cardinality
1714  * and sequence order is preserved per sender/receiver socket pair.
1715  * Owner node is locked.
1716  */
1717 void tipc_link_dup_queue_xmit(struct tipc_link *link,
1718                               struct tipc_link *tnl)
1719 {
1720         struct sk_buff *skb;
1721         struct tipc_msg tnl_hdr;
1722         struct sk_buff_head *queue = &link->transmq;
1723         int mcnt;
1724
1725         tipc_msg_init(link_own_addr(link), &tnl_hdr, CHANGEOVER_PROTOCOL,
1726                       DUPLICATE_MSG, INT_H_SIZE, link->addr);
1727         mcnt = skb_queue_len(&link->transmq) + skb_queue_len(&link->backlogq);
1728         msg_set_msgcnt(&tnl_hdr, mcnt);
1729         msg_set_bearer_id(&tnl_hdr, link->peer_bearer_id);
1730
1731 tunnel_queue:
1732         skb_queue_walk(queue, skb) {
1733                 struct sk_buff *outskb;
1734                 struct tipc_msg *msg = buf_msg(skb);
1735                 u32 len = msg_size(msg);
1736
1737                 msg_set_ack(msg, mod(link->next_in_no - 1));
1738                 msg_set_bcast_ack(msg, link->owner->bclink.last_in);
1739                 msg_set_size(&tnl_hdr, len + INT_H_SIZE);
1740                 outskb = tipc_buf_acquire(len + INT_H_SIZE);
1741                 if (outskb == NULL) {
1742                         pr_warn("%sunable to send duplicate msg\n",
1743                                 link_co_err);
1744                         return;
1745                 }
1746                 skb_copy_to_linear_data(outskb, &tnl_hdr, INT_H_SIZE);
1747                 skb_copy_to_linear_data_offset(outskb, INT_H_SIZE,
1748                                                skb->data, len);
1749                 __tipc_link_xmit_skb(tnl, outskb);
1750                 if (!tipc_link_is_up(link))
1751                         return;
1752         }
1753         if (queue == &link->backlogq)
1754                 return;
1755         queue = &link->backlogq;
1756         goto tunnel_queue;
1757 }
1758
1759 /* tipc_link_dup_rcv(): Receive a tunnelled DUPLICATE_MSG packet.
1760  * Owner node is locked.
1761  */
1762 static void tipc_link_dup_rcv(struct tipc_link *link,
1763                               struct sk_buff *skb)
1764 {
1765         struct sk_buff *iskb;
1766         int pos = 0;
1767
1768         if (!tipc_link_is_up(link))
1769                 return;
1770
1771         if (!tipc_msg_extract(skb, &iskb, &pos)) {
1772                 pr_warn("%sfailed to extract inner dup pkt\n", link_co_err);
1773                 return;
1774         }
1775         /* Append buffer to deferred queue, if applicable: */
1776         link_handle_out_of_seq_msg(link, iskb);
1777 }
1778
1779 /*  tipc_link_failover_rcv(): Receive a tunnelled ORIGINAL_MSG packet
1780  *  Owner node is locked.
1781  */
1782 static struct sk_buff *tipc_link_failover_rcv(struct tipc_link *l_ptr,
1783                                               struct sk_buff *t_buf)
1784 {
1785         struct tipc_msg *t_msg = buf_msg(t_buf);
1786         struct sk_buff *buf = NULL;
1787         struct tipc_msg *msg;
1788         int pos = 0;
1789
1790         if (tipc_link_is_up(l_ptr))
1791                 tipc_link_reset(l_ptr);
1792
1793         /* First failover packet? */
1794         if (l_ptr->exp_msg_count == START_CHANGEOVER)
1795                 l_ptr->exp_msg_count = msg_msgcnt(t_msg);
1796
1797         /* Should there be an inner packet? */
1798         if (l_ptr->exp_msg_count) {
1799                 l_ptr->exp_msg_count--;
1800                 if (!tipc_msg_extract(t_buf, &buf, &pos)) {
1801                         pr_warn("%sno inner failover pkt\n", link_co_err);
1802                         goto exit;
1803                 }
1804                 msg = buf_msg(buf);
1805
1806                 if (less(msg_seqno(msg), l_ptr->reset_checkpoint)) {
1807                         kfree_skb(buf);
1808                         buf = NULL;
1809                         goto exit;
1810                 }
1811                 if (msg_user(msg) == MSG_FRAGMENTER) {
1812                         l_ptr->stats.recv_fragments++;
1813                         tipc_buf_append(&l_ptr->reasm_buf, &buf);
1814                 }
1815         }
1816 exit:
1817         if ((!l_ptr->exp_msg_count) && (l_ptr->flags & LINK_STOPPED))
1818                 tipc_link_delete(l_ptr);
1819         return buf;
1820 }
1821
1822 /*  tipc_link_tunnel_rcv(): Receive a tunnelled packet, sent
1823  *  via other link as result of a failover (ORIGINAL_MSG) or
1824  *  a new active link (DUPLICATE_MSG). Failover packets are
1825  *  returned to the active link for delivery upwards.
1826  *  Owner node is locked.
1827  */
1828 static int tipc_link_tunnel_rcv(struct tipc_node *n_ptr,
1829                                 struct sk_buff **buf)
1830 {
1831         struct sk_buff *t_buf = *buf;
1832         struct tipc_link *l_ptr;
1833         struct tipc_msg *t_msg = buf_msg(t_buf);
1834         u32 bearer_id = msg_bearer_id(t_msg);
1835
1836         *buf = NULL;
1837
1838         if (bearer_id >= MAX_BEARERS)
1839                 goto exit;
1840
1841         l_ptr = n_ptr->links[bearer_id];
1842         if (!l_ptr)
1843                 goto exit;
1844
1845         if (msg_type(t_msg) == DUPLICATE_MSG)
1846                 tipc_link_dup_rcv(l_ptr, t_buf);
1847         else if (msg_type(t_msg) == ORIGINAL_MSG)
1848                 *buf = tipc_link_failover_rcv(l_ptr, t_buf);
1849         else
1850                 pr_warn("%sunknown tunnel pkt received\n", link_co_err);
1851 exit:
1852         kfree_skb(t_buf);
1853         return *buf != NULL;
1854 }
1855
1856 static void link_set_supervision_props(struct tipc_link *l_ptr, u32 tol)
1857 {
1858         unsigned long intv = ((tol / 4) > 500) ? 500 : tol / 4;
1859
1860         if ((tol < TIPC_MIN_LINK_TOL) || (tol > TIPC_MAX_LINK_TOL))
1861                 return;
1862
1863         l_ptr->tolerance = tol;
1864         l_ptr->cont_intv = msecs_to_jiffies(intv);
1865         l_ptr->abort_limit = tol / (jiffies_to_msecs(l_ptr->cont_intv) / 4);
1866 }
1867
1868 void tipc_link_set_queue_limits(struct tipc_link *l, u32 win)
1869 {
1870         int max_bulk = TIPC_MAX_PUBLICATIONS / (l->max_pkt / ITEM_SIZE);
1871
1872         l->window = win;
1873         l->backlog[TIPC_LOW_IMPORTANCE].limit      = win / 2;
1874         l->backlog[TIPC_MEDIUM_IMPORTANCE].limit   = win;
1875         l->backlog[TIPC_HIGH_IMPORTANCE].limit     = win / 2 * 3;
1876         l->backlog[TIPC_CRITICAL_IMPORTANCE].limit = win * 2;
1877         l->backlog[TIPC_SYSTEM_IMPORTANCE].limit   = max_bulk;
1878 }
1879
1880 /* tipc_link_find_owner - locate owner node of link by link's name
1881  * @net: the applicable net namespace
1882  * @name: pointer to link name string
1883  * @bearer_id: pointer to index in 'node->links' array where the link was found.
1884  *
1885  * Returns pointer to node owning the link, or 0 if no matching link is found.
1886  */
1887 static struct tipc_node *tipc_link_find_owner(struct net *net,
1888                                               const char *link_name,
1889                                               unsigned int *bearer_id)
1890 {
1891         struct tipc_net *tn = net_generic(net, tipc_net_id);
1892         struct tipc_link *l_ptr;
1893         struct tipc_node *n_ptr;
1894         struct tipc_node *found_node = NULL;
1895         int i;
1896
1897         *bearer_id = 0;
1898         rcu_read_lock();
1899         list_for_each_entry_rcu(n_ptr, &tn->node_list, list) {
1900                 tipc_node_lock(n_ptr);
1901                 for (i = 0; i < MAX_BEARERS; i++) {
1902                         l_ptr = n_ptr->links[i];
1903                         if (l_ptr && !strcmp(l_ptr->name, link_name)) {
1904                                 *bearer_id = i;
1905                                 found_node = n_ptr;
1906                                 break;
1907                         }
1908                 }
1909                 tipc_node_unlock(n_ptr);
1910                 if (found_node)
1911                         break;
1912         }
1913         rcu_read_unlock();
1914
1915         return found_node;
1916 }
1917
1918 /**
1919  * link_reset_statistics - reset link statistics
1920  * @l_ptr: pointer to link
1921  */
1922 static void link_reset_statistics(struct tipc_link *l_ptr)
1923 {
1924         memset(&l_ptr->stats, 0, sizeof(l_ptr->stats));
1925         l_ptr->stats.sent_info = l_ptr->next_out_no;
1926         l_ptr->stats.recv_info = l_ptr->next_in_no;
1927 }
1928
1929 static void link_print(struct tipc_link *l_ptr, const char *str)
1930 {
1931         struct tipc_net *tn = net_generic(l_ptr->owner->net, tipc_net_id);
1932         struct tipc_bearer *b_ptr;
1933
1934         rcu_read_lock();
1935         b_ptr = rcu_dereference_rtnl(tn->bearer_list[l_ptr->bearer_id]);
1936         if (b_ptr)
1937                 pr_info("%s Link %x<%s>:", str, l_ptr->addr, b_ptr->name);
1938         rcu_read_unlock();
1939
1940         if (link_working_unknown(l_ptr))
1941                 pr_cont(":WU\n");
1942         else if (link_reset_reset(l_ptr))
1943                 pr_cont(":RR\n");
1944         else if (link_reset_unknown(l_ptr))
1945                 pr_cont(":RU\n");
1946         else if (link_working_working(l_ptr))
1947                 pr_cont(":WW\n");
1948         else
1949                 pr_cont("\n");
1950 }
1951
1952 /* Parse and validate nested (link) properties valid for media, bearer and link
1953  */
1954 int tipc_nl_parse_link_prop(struct nlattr *prop, struct nlattr *props[])
1955 {
1956         int err;
1957
1958         err = nla_parse_nested(props, TIPC_NLA_PROP_MAX, prop,
1959                                tipc_nl_prop_policy);
1960         if (err)
1961                 return err;
1962
1963         if (props[TIPC_NLA_PROP_PRIO]) {
1964                 u32 prio;
1965
1966                 prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
1967                 if (prio > TIPC_MAX_LINK_PRI)
1968                         return -EINVAL;
1969         }
1970
1971         if (props[TIPC_NLA_PROP_TOL]) {
1972                 u32 tol;
1973
1974                 tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
1975                 if ((tol < TIPC_MIN_LINK_TOL) || (tol > TIPC_MAX_LINK_TOL))
1976                         return -EINVAL;
1977         }
1978
1979         if (props[TIPC_NLA_PROP_WIN]) {
1980                 u32 win;
1981
1982                 win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
1983                 if ((win < TIPC_MIN_LINK_WIN) || (win > TIPC_MAX_LINK_WIN))
1984                         return -EINVAL;
1985         }
1986
1987         return 0;
1988 }
1989
1990 int tipc_nl_link_set(struct sk_buff *skb, struct genl_info *info)
1991 {
1992         int err;
1993         int res = 0;
1994         int bearer_id;
1995         char *name;
1996         struct tipc_link *link;
1997         struct tipc_node *node;
1998         struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
1999         struct net *net = sock_net(skb->sk);
2000
2001         if (!info->attrs[TIPC_NLA_LINK])
2002                 return -EINVAL;
2003
2004         err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
2005                                info->attrs[TIPC_NLA_LINK],
2006                                tipc_nl_link_policy);
2007         if (err)
2008                 return err;
2009
2010         if (!attrs[TIPC_NLA_LINK_NAME])
2011                 return -EINVAL;
2012
2013         name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
2014
2015         node = tipc_link_find_owner(net, name, &bearer_id);
2016         if (!node)
2017                 return -EINVAL;
2018
2019         tipc_node_lock(node);
2020
2021         link = node->links[bearer_id];
2022         if (!link) {
2023                 res = -EINVAL;
2024                 goto out;
2025         }
2026
2027         if (attrs[TIPC_NLA_LINK_PROP]) {
2028                 struct nlattr *props[TIPC_NLA_PROP_MAX + 1];
2029
2030                 err = tipc_nl_parse_link_prop(attrs[TIPC_NLA_LINK_PROP],
2031                                               props);
2032                 if (err) {
2033                         res = err;
2034                         goto out;
2035                 }
2036
2037                 if (props[TIPC_NLA_PROP_TOL]) {
2038                         u32 tol;
2039
2040                         tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
2041                         link_set_supervision_props(link, tol);
2042                         tipc_link_proto_xmit(link, STATE_MSG, 0, 0, tol, 0, 0);
2043                 }
2044                 if (props[TIPC_NLA_PROP_PRIO]) {
2045                         u32 prio;
2046
2047                         prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
2048                         link->priority = prio;
2049                         tipc_link_proto_xmit(link, STATE_MSG, 0, 0, 0, prio, 0);
2050                 }
2051                 if (props[TIPC_NLA_PROP_WIN]) {
2052                         u32 win;
2053
2054                         win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
2055                         tipc_link_set_queue_limits(link, win);
2056                 }
2057         }
2058
2059 out:
2060         tipc_node_unlock(node);
2061
2062         return res;
2063 }
2064
2065 static int __tipc_nl_add_stats(struct sk_buff *skb, struct tipc_stats *s)
2066 {
2067         int i;
2068         struct nlattr *stats;
2069
2070         struct nla_map {
2071                 u32 key;
2072                 u32 val;
2073         };
2074
2075         struct nla_map map[] = {
2076                 {TIPC_NLA_STATS_RX_INFO, s->recv_info},
2077                 {TIPC_NLA_STATS_RX_FRAGMENTS, s->recv_fragments},
2078                 {TIPC_NLA_STATS_RX_FRAGMENTED, s->recv_fragmented},
2079                 {TIPC_NLA_STATS_RX_BUNDLES, s->recv_bundles},
2080                 {TIPC_NLA_STATS_RX_BUNDLED, s->recv_bundled},
2081                 {TIPC_NLA_STATS_TX_INFO, s->sent_info},
2082                 {TIPC_NLA_STATS_TX_FRAGMENTS, s->sent_fragments},
2083                 {TIPC_NLA_STATS_TX_FRAGMENTED, s->sent_fragmented},
2084                 {TIPC_NLA_STATS_TX_BUNDLES, s->sent_bundles},
2085                 {TIPC_NLA_STATS_TX_BUNDLED, s->sent_bundled},
2086                 {TIPC_NLA_STATS_MSG_PROF_TOT, (s->msg_length_counts) ?
2087                         s->msg_length_counts : 1},
2088                 {TIPC_NLA_STATS_MSG_LEN_CNT, s->msg_length_counts},
2089                 {TIPC_NLA_STATS_MSG_LEN_TOT, s->msg_lengths_total},
2090                 {TIPC_NLA_STATS_MSG_LEN_P0, s->msg_length_profile[0]},
2091                 {TIPC_NLA_STATS_MSG_LEN_P1, s->msg_length_profile[1]},
2092                 {TIPC_NLA_STATS_MSG_LEN_P2, s->msg_length_profile[2]},
2093                 {TIPC_NLA_STATS_MSG_LEN_P3, s->msg_length_profile[3]},
2094                 {TIPC_NLA_STATS_MSG_LEN_P4, s->msg_length_profile[4]},
2095                 {TIPC_NLA_STATS_MSG_LEN_P5, s->msg_length_profile[5]},
2096                 {TIPC_NLA_STATS_MSG_LEN_P6, s->msg_length_profile[6]},
2097                 {TIPC_NLA_STATS_RX_STATES, s->recv_states},
2098                 {TIPC_NLA_STATS_RX_PROBES, s->recv_probes},
2099                 {TIPC_NLA_STATS_RX_NACKS, s->recv_nacks},
2100                 {TIPC_NLA_STATS_RX_DEFERRED, s->deferred_recv},
2101                 {TIPC_NLA_STATS_TX_STATES, s->sent_states},
2102                 {TIPC_NLA_STATS_TX_PROBES, s->sent_probes},
2103                 {TIPC_NLA_STATS_TX_NACKS, s->sent_nacks},
2104                 {TIPC_NLA_STATS_TX_ACKS, s->sent_acks},
2105                 {TIPC_NLA_STATS_RETRANSMITTED, s->retransmitted},
2106                 {TIPC_NLA_STATS_DUPLICATES, s->duplicates},
2107                 {TIPC_NLA_STATS_LINK_CONGS, s->link_congs},
2108                 {TIPC_NLA_STATS_MAX_QUEUE, s->max_queue_sz},
2109                 {TIPC_NLA_STATS_AVG_QUEUE, s->queue_sz_counts ?
2110                         (s->accu_queue_sz / s->queue_sz_counts) : 0}
2111         };
2112
2113         stats = nla_nest_start(skb, TIPC_NLA_LINK_STATS);
2114         if (!stats)
2115                 return -EMSGSIZE;
2116
2117         for (i = 0; i <  ARRAY_SIZE(map); i++)
2118                 if (nla_put_u32(skb, map[i].key, map[i].val))
2119                         goto msg_full;
2120
2121         nla_nest_end(skb, stats);
2122
2123         return 0;
2124 msg_full:
2125         nla_nest_cancel(skb, stats);
2126
2127         return -EMSGSIZE;
2128 }
2129
2130 /* Caller should hold appropriate locks to protect the link */
2131 static int __tipc_nl_add_link(struct net *net, struct tipc_nl_msg *msg,
2132                               struct tipc_link *link)
2133 {
2134         int err;
2135         void *hdr;
2136         struct nlattr *attrs;
2137         struct nlattr *prop;
2138         struct tipc_net *tn = net_generic(net, tipc_net_id);
2139
2140         hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
2141                           NLM_F_MULTI, TIPC_NL_LINK_GET);
2142         if (!hdr)
2143                 return -EMSGSIZE;
2144
2145         attrs = nla_nest_start(msg->skb, TIPC_NLA_LINK);
2146         if (!attrs)
2147                 goto msg_full;
2148
2149         if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, link->name))
2150                 goto attr_msg_full;
2151         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_DEST,
2152                         tipc_cluster_mask(tn->own_addr)))
2153                 goto attr_msg_full;
2154         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_MTU, link->max_pkt))
2155                 goto attr_msg_full;
2156         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, link->next_in_no))
2157                 goto attr_msg_full;
2158         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, link->next_out_no))
2159                 goto attr_msg_full;
2160
2161         if (tipc_link_is_up(link))
2162                 if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
2163                         goto attr_msg_full;
2164         if (tipc_link_is_active(link))
2165                 if (nla_put_flag(msg->skb, TIPC_NLA_LINK_ACTIVE))
2166                         goto attr_msg_full;
2167
2168         prop = nla_nest_start(msg->skb, TIPC_NLA_LINK_PROP);
2169         if (!prop)
2170                 goto attr_msg_full;
2171         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
2172                 goto prop_msg_full;
2173         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_TOL, link->tolerance))
2174                 goto prop_msg_full;
2175         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN,
2176                         link->window))
2177                 goto prop_msg_full;
2178         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
2179                 goto prop_msg_full;
2180         nla_nest_end(msg->skb, prop);
2181
2182         err = __tipc_nl_add_stats(msg->skb, &link->stats);
2183         if (err)
2184                 goto attr_msg_full;
2185
2186         nla_nest_end(msg->skb, attrs);
2187         genlmsg_end(msg->skb, hdr);
2188
2189         return 0;
2190
2191 prop_msg_full:
2192         nla_nest_cancel(msg->skb, prop);
2193 attr_msg_full:
2194         nla_nest_cancel(msg->skb, attrs);
2195 msg_full:
2196         genlmsg_cancel(msg->skb, hdr);
2197
2198         return -EMSGSIZE;
2199 }
2200
2201 /* Caller should hold node lock  */
2202 static int __tipc_nl_add_node_links(struct net *net, struct tipc_nl_msg *msg,
2203                                     struct tipc_node *node, u32 *prev_link)
2204 {
2205         u32 i;
2206         int err;
2207
2208         for (i = *prev_link; i < MAX_BEARERS; i++) {
2209                 *prev_link = i;
2210
2211                 if (!node->links[i])
2212                         continue;
2213
2214                 err = __tipc_nl_add_link(net, msg, node->links[i]);
2215                 if (err)
2216                         return err;
2217         }
2218         *prev_link = 0;
2219
2220         return 0;
2221 }
2222
2223 int tipc_nl_link_dump(struct sk_buff *skb, struct netlink_callback *cb)
2224 {
2225         struct net *net = sock_net(skb->sk);
2226         struct tipc_net *tn = net_generic(net, tipc_net_id);
2227         struct tipc_node *node;
2228         struct tipc_nl_msg msg;
2229         u32 prev_node = cb->args[0];
2230         u32 prev_link = cb->args[1];
2231         int done = cb->args[2];
2232         int err;
2233
2234         if (done)
2235                 return 0;
2236
2237         msg.skb = skb;
2238         msg.portid = NETLINK_CB(cb->skb).portid;
2239         msg.seq = cb->nlh->nlmsg_seq;
2240
2241         rcu_read_lock();
2242
2243         if (prev_node) {
2244                 node = tipc_node_find(net, prev_node);
2245                 if (!node) {
2246                         /* We never set seq or call nl_dump_check_consistent()
2247                          * this means that setting prev_seq here will cause the
2248                          * consistence check to fail in the netlink callback
2249                          * handler. Resulting in the last NLMSG_DONE message
2250                          * having the NLM_F_DUMP_INTR flag set.
2251                          */
2252                         cb->prev_seq = 1;
2253                         goto out;
2254                 }
2255
2256                 list_for_each_entry_continue_rcu(node, &tn->node_list,
2257                                                  list) {
2258                         tipc_node_lock(node);
2259                         err = __tipc_nl_add_node_links(net, &msg, node,
2260                                                        &prev_link);
2261                         tipc_node_unlock(node);
2262                         if (err)
2263                                 goto out;
2264
2265                         prev_node = node->addr;
2266                 }
2267         } else {
2268                 err = tipc_nl_add_bc_link(net, &msg);
2269                 if (err)
2270                         goto out;
2271
2272                 list_for_each_entry_rcu(node, &tn->node_list, list) {
2273                         tipc_node_lock(node);
2274                         err = __tipc_nl_add_node_links(net, &msg, node,
2275                                                        &prev_link);
2276                         tipc_node_unlock(node);
2277                         if (err)
2278                                 goto out;
2279
2280                         prev_node = node->addr;
2281                 }
2282         }
2283         done = 1;
2284 out:
2285         rcu_read_unlock();
2286
2287         cb->args[0] = prev_node;
2288         cb->args[1] = prev_link;
2289         cb->args[2] = done;
2290
2291         return skb->len;
2292 }
2293
2294 int tipc_nl_link_get(struct sk_buff *skb, struct genl_info *info)
2295 {
2296         struct net *net = genl_info_net(info);
2297         struct sk_buff *ans_skb;
2298         struct tipc_nl_msg msg;
2299         struct tipc_link *link;
2300         struct tipc_node *node;
2301         char *name;
2302         int bearer_id;
2303         int err;
2304
2305         if (!info->attrs[TIPC_NLA_LINK_NAME])
2306                 return -EINVAL;
2307
2308         name = nla_data(info->attrs[TIPC_NLA_LINK_NAME]);
2309         node = tipc_link_find_owner(net, name, &bearer_id);
2310         if (!node)
2311                 return -EINVAL;
2312
2313         ans_skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
2314         if (!ans_skb)
2315                 return -ENOMEM;
2316
2317         msg.skb = ans_skb;
2318         msg.portid = info->snd_portid;
2319         msg.seq = info->snd_seq;
2320
2321         tipc_node_lock(node);
2322         link = node->links[bearer_id];
2323         if (!link) {
2324                 err = -EINVAL;
2325                 goto err_out;
2326         }
2327
2328         err = __tipc_nl_add_link(net, &msg, link);
2329         if (err)
2330                 goto err_out;
2331
2332         tipc_node_unlock(node);
2333
2334         return genlmsg_reply(ans_skb, info);
2335
2336 err_out:
2337         tipc_node_unlock(node);
2338         nlmsg_free(ans_skb);
2339
2340         return err;
2341 }
2342
2343 int tipc_nl_link_reset_stats(struct sk_buff *skb, struct genl_info *info)
2344 {
2345         int err;
2346         char *link_name;
2347         unsigned int bearer_id;
2348         struct tipc_link *link;
2349         struct tipc_node *node;
2350         struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
2351         struct net *net = sock_net(skb->sk);
2352
2353         if (!info->attrs[TIPC_NLA_LINK])
2354                 return -EINVAL;
2355
2356         err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
2357                                info->attrs[TIPC_NLA_LINK],
2358                                tipc_nl_link_policy);
2359         if (err)
2360                 return err;
2361
2362         if (!attrs[TIPC_NLA_LINK_NAME])
2363                 return -EINVAL;
2364
2365         link_name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
2366
2367         if (strcmp(link_name, tipc_bclink_name) == 0) {
2368                 err = tipc_bclink_reset_stats(net);
2369                 if (err)
2370                         return err;
2371                 return 0;
2372         }
2373
2374         node = tipc_link_find_owner(net, link_name, &bearer_id);
2375         if (!node)
2376                 return -EINVAL;
2377
2378         tipc_node_lock(node);
2379
2380         link = node->links[bearer_id];
2381         if (!link) {
2382                 tipc_node_unlock(node);
2383                 return -EINVAL;
2384         }
2385
2386         link_reset_statistics(link);
2387
2388         tipc_node_unlock(node);
2389
2390         return 0;
2391 }