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