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 tunneling error, ";
  52 static const char *link_rst_msg = "Resetting link ";
  53
  54 static const struct nla_policy tipc_nl_link_policy[TIPC_NLA_LINK_MAX + 1] = {
  55         [TIPC_NLA_LINK_UNSPEC]          = { .type = NLA_UNSPEC },
  56         [TIPC_NLA_LINK_NAME] = {
  57                 .type = NLA_STRING,
  58                 .len = TIPC_MAX_LINK_NAME
  59         },
  60         [TIPC_NLA_LINK_MTU]             = { .type = NLA_U32 },
  61         [TIPC_NLA_LINK_BROADCAST]       = { .type = NLA_FLAG },
  62         [TIPC_NLA_LINK_UP]              = { .type = NLA_FLAG },
  63         [TIPC_NLA_LINK_ACTIVE]          = { .type = NLA_FLAG },
  64         [TIPC_NLA_LINK_PROP]            = { .type = NLA_NESTED },
  65         [TIPC_NLA_LINK_STATS]           = { .type = NLA_NESTED },
  66         [TIPC_NLA_LINK_RX]              = { .type = NLA_U32 },
  67         [TIPC_NLA_LINK_TX]              = { .type = NLA_U32 }
  68 };
  69
  70 /* Properties valid for media, bearar and link */
  71 static const struct nla_policy tipc_nl_prop_policy[TIPC_NLA_PROP_MAX + 1] = {
  72         [TIPC_NLA_PROP_UNSPEC]          = { .type = NLA_UNSPEC },
  73         [TIPC_NLA_PROP_PRIO]            = { .type = NLA_U32 },
  74         [TIPC_NLA_PROP_TOL]             = { .type = NLA_U32 },
  75         [TIPC_NLA_PROP_WIN]             = { .type = NLA_U32 }
  76 };
  77
  78 /*
  79  * Interval between NACKs when packets arrive out of order
  80  */
  81 #define TIPC_NACK_INTV (TIPC_MIN_LINK_WIN * 2)
  82 /*
  83  * Out-of-range value for link session numbers
  84  */
  85 #define WILDCARD_SESSION 0x10000
  86
  87 /* Link FSM states:
  88  */
  89 enum {
  90         LINK_ESTABLISHED     = 0xe,
  91         LINK_ESTABLISHING    = 0xe  << 4,
  92         LINK_RESET           = 0x1  << 8,
  93         LINK_RESETTING       = 0x2  << 12,
  94         LINK_PEER_RESET      = 0xd  << 16,
  95         LINK_FAILINGOVER     = 0xf  << 20,
  96         LINK_SYNCHING        = 0xc  << 24
  97 };
  98
  99 /* Link FSM state checking routines
 100  */
 101 static int link_is_up(struct tipc_link *l)
 102 {
 103         return l->state & (LINK_ESTABLISHED | LINK_SYNCHING);
 104 }
 105
 106 static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
 107                                struct sk_buff_head *xmitq);
 108 static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
 109                                       u16 rcvgap, int tolerance, int priority,
 110                                       struct sk_buff_head *xmitq);
 111 static void link_reset_statistics(struct tipc_link *l_ptr);
 112 static void link_print(struct tipc_link *l_ptr, const char *str);
 113 static void tipc_link_sync_rcv(struct tipc_node *n, struct sk_buff *buf);
 114
 115 /*
 116  *  Simple non-static link routines (i.e. referenced outside this file)
 117  */
 118 bool tipc_link_is_up(struct tipc_link *l)
 119 {
 120         return link_is_up(l);
 121 }
 122
 123 bool tipc_link_is_reset(struct tipc_link *l)
 124 {
 125         return l->state & (LINK_RESET | LINK_FAILINGOVER | LINK_ESTABLISHING);
 126 }
 127
 128 bool tipc_link_is_synching(struct tipc_link *l)
 129 {
 130         return l->state == LINK_SYNCHING;
 131 }
 132
 133 bool tipc_link_is_failingover(struct tipc_link *l)
 134 {
 135         return l->state == LINK_FAILINGOVER;
 136 }
 137
 138 bool tipc_link_is_blocked(struct tipc_link *l)
 139 {
 140         return l->state & (LINK_RESETTING | LINK_PEER_RESET | LINK_FAILINGOVER);
 141 }
 142
 143 int tipc_link_is_active(struct tipc_link *l)
 144 {
 145         struct tipc_node *n = l->owner;
 146
 147         return (node_active_link(n, 0) == l) || (node_active_link(n, 1) == l);
 148 }
 149
 150 static u32 link_own_addr(struct tipc_link *l)
 151 {
 152         return msg_prevnode(l->pmsg);
 153 }
 154
 155 /**
 156  * tipc_link_create - create a new link
 157  * @n: pointer to associated node
 158  * @b: pointer to associated bearer
 159  * @ownnode: identity of own node
 160  * @peer: identity of peer node
 161  * @maddr: media address to be used
 162  * @inputq: queue to put messages ready for delivery
 163  * @namedq: queue to put binding table update messages ready for delivery
 164  * @link: return value, pointer to put the created link
 165  *
 166  * Returns true if link was created, otherwise false
 167  */
 168 bool tipc_link_create(struct tipc_node *n, struct tipc_bearer *b, u32 session,
 169                       u32 ownnode, u32 peer, struct tipc_media_addr *maddr,
 170                       struct sk_buff_head *inputq, struct sk_buff_head *namedq,
 171                       struct tipc_link **link)
 172 {
 173         struct tipc_link *l;
 174         struct tipc_msg *hdr;
 175         char *if_name;
 176
 177         l = kzalloc(sizeof(*l), GFP_ATOMIC);
 178         if (!l)
 179                 return false;
 180         *link = l;
 181
 182         /* Note: peer i/f name is completed by reset/activate message */
 183         if_name = strchr(b->name, ':') + 1;
 184         sprintf(l->name, "%u.%u.%u:%s-%u.%u.%u:unknown",
 185                 tipc_zone(ownnode), tipc_cluster(ownnode), tipc_node(ownnode),
 186                 if_name, tipc_zone(peer), tipc_cluster(peer), tipc_node(peer));
 187
 188         l->addr = peer;
 189         l->media_addr = maddr;
 190         l->owner = n;
 191         l->peer_session = WILDCARD_SESSION;
 192         l->bearer_id = b->identity;
 193         l->tolerance = b->tolerance;
 194         l->net_plane = b->net_plane;
 195         l->advertised_mtu = b->mtu;
 196         l->mtu = b->mtu;
 197         l->priority = b->priority;
 198         tipc_link_set_queue_limits(l, b->window);
 199         l->inputq = inputq;
 200         l->namedq = namedq;
 201         l->state = LINK_RESETTING;
 202         l->pmsg = (struct tipc_msg *)&l->proto_msg;
 203         hdr = l->pmsg;
 204         tipc_msg_init(ownnode, hdr, LINK_PROTOCOL, RESET_MSG, INT_H_SIZE, peer);
 205         msg_set_size(hdr, sizeof(l->proto_msg));
 206         msg_set_session(hdr, session);
 207         msg_set_bearer_id(hdr, l->bearer_id);
 208         strcpy((char *)msg_data(hdr), if_name);
 209         __skb_queue_head_init(&l->transmq);
 210         __skb_queue_head_init(&l->backlogq);
 211         __skb_queue_head_init(&l->deferdq);
 212         skb_queue_head_init(&l->wakeupq);
 213         skb_queue_head_init(l->inputq);
 214         return true;
 215 }
 216
 217 /* tipc_link_build_bcast_sync_msg() - synchronize broadcast link endpoints.
 218  *
 219  * Give a newly added peer node the sequence number where it should
 220  * start receiving and acking broadcast packets.
 221  */
 222 void tipc_link_build_bcast_sync_msg(struct tipc_link *l,
 223                                     struct sk_buff_head *xmitq)
 224 {
 225         struct sk_buff *skb;
 226         struct sk_buff_head list;
 227         u16 last_sent;
 228
 229         skb = tipc_msg_create(BCAST_PROTOCOL, STATE_MSG, INT_H_SIZE,
 230                               0, l->addr, link_own_addr(l), 0, 0, 0);
 231         if (!skb)
 232                 return;
 233         last_sent = tipc_bclink_get_last_sent(l->owner->net);
 234         msg_set_last_bcast(buf_msg(skb), last_sent);
 235         __skb_queue_head_init(&list);
 236         __skb_queue_tail(&list, skb);
 237         tipc_link_xmit(l, &list, xmitq);
 238 }
 239
 240 /**
 241  * tipc_link_fsm_evt - link finite state machine
 242  * @l: pointer to link
 243  * @evt: state machine event to be processed
 244  */
 245 int tipc_link_fsm_evt(struct tipc_link *l, int evt)
 246 {
 247         int rc = 0;
 248
 249         switch (l->state) {
 250         case LINK_RESETTING:
 251                 switch (evt) {
 252                 case LINK_PEER_RESET_EVT:
 253                         l->state = LINK_PEER_RESET;
 254                         break;
 255                 case LINK_RESET_EVT:
 256                         l->state = LINK_RESET;
 257                         break;
 258                 case LINK_FAILURE_EVT:
 259                 case LINK_FAILOVER_BEGIN_EVT:
 260                 case LINK_ESTABLISH_EVT:
 261                 case LINK_FAILOVER_END_EVT:
 262                 case LINK_SYNCH_BEGIN_EVT:
 263                 case LINK_SYNCH_END_EVT:
 264                 default:
 265                         goto illegal_evt;
 266                 }
 267                 break;
 268         case LINK_RESET:
 269                 switch (evt) {
 270                 case LINK_PEER_RESET_EVT:
 271                         l->state = LINK_ESTABLISHING;
 272                         break;
 273                 case LINK_FAILOVER_BEGIN_EVT:
 274                         l->state = LINK_FAILINGOVER;
 275                 case LINK_FAILURE_EVT:
 276                 case LINK_RESET_EVT:
 277                 case LINK_ESTABLISH_EVT:
 278                 case LINK_FAILOVER_END_EVT:
 279                         break;
 280                 case LINK_SYNCH_BEGIN_EVT:
 281                 case LINK_SYNCH_END_EVT:
 282                 default:
 283                         goto illegal_evt;
 284                 }
 285                 break;
 286         case LINK_PEER_RESET:
 287                 switch (evt) {
 288                 case LINK_RESET_EVT:
 289                         l->state = LINK_ESTABLISHING;
 290                         break;
 291                 case LINK_PEER_RESET_EVT:
 292                 case LINK_ESTABLISH_EVT:
 293                 case LINK_FAILURE_EVT:
 294                         break;
 295                 case LINK_SYNCH_BEGIN_EVT:
 296                 case LINK_SYNCH_END_EVT:
 297                 case LINK_FAILOVER_BEGIN_EVT:
 298                 case LINK_FAILOVER_END_EVT:
 299                 default:
 300                         goto illegal_evt;
 301                 }
 302                 break;
 303         case LINK_FAILINGOVER:
 304                 switch (evt) {
 305                 case LINK_FAILOVER_END_EVT:
 306                         l->state = LINK_RESET;
 307                         break;
 308                 case LINK_PEER_RESET_EVT:
 309                 case LINK_RESET_EVT:
 310                 case LINK_ESTABLISH_EVT:
 311                 case LINK_FAILURE_EVT:
 312                         break;
 313                 case LINK_FAILOVER_BEGIN_EVT:
 314                 case LINK_SYNCH_BEGIN_EVT:
 315                 case LINK_SYNCH_END_EVT:
 316                 default:
 317                         goto illegal_evt;
 318                 }
 319                 break;
 320         case LINK_ESTABLISHING:
 321                 switch (evt) {
 322                 case LINK_ESTABLISH_EVT:
 323                         l->state = LINK_ESTABLISHED;
 324                         rc |= TIPC_LINK_UP_EVT;
 325                         break;
 326                 case LINK_FAILOVER_BEGIN_EVT:
 327                         l->state = LINK_FAILINGOVER;
 328                         break;
 329                 case LINK_PEER_RESET_EVT:
 330                 case LINK_RESET_EVT:
 331                 case LINK_FAILURE_EVT:
 332                 case LINK_SYNCH_BEGIN_EVT:
 333                 case LINK_FAILOVER_END_EVT:
 334                         break;
 335                 case LINK_SYNCH_END_EVT:
 336                 default:
 337                         goto illegal_evt;
 338                 }
 339                 break;
 340         case LINK_ESTABLISHED:
 341                 switch (evt) {
 342                 case LINK_PEER_RESET_EVT:
 343                         l->state = LINK_PEER_RESET;
 344                         rc |= TIPC_LINK_DOWN_EVT;
 345                         break;
 346                 case LINK_FAILURE_EVT:
 347                         l->state = LINK_RESETTING;
 348                         rc |= TIPC_LINK_DOWN_EVT;
 349                         break;
 350                 case LINK_RESET_EVT:
 351                         l->state = LINK_RESET;
 352                         break;
 353                 case LINK_ESTABLISH_EVT:
 354                 case LINK_SYNCH_END_EVT:
 355                         break;
 356                 case LINK_SYNCH_BEGIN_EVT:
 357                         l->state = LINK_SYNCHING;
 358                         break;
 359                 case LINK_FAILOVER_BEGIN_EVT:
 360                 case LINK_FAILOVER_END_EVT:
 361                 default:
 362                         goto illegal_evt;
 363                 }
 364                 break;
 365         case LINK_SYNCHING:
 366                 switch (evt) {
 367                 case LINK_PEER_RESET_EVT:
 368                         l->state = LINK_PEER_RESET;
 369                         rc |= TIPC_LINK_DOWN_EVT;
 370                         break;
 371                 case LINK_FAILURE_EVT:
 372                         l->state = LINK_RESETTING;
 373                         rc |= TIPC_LINK_DOWN_EVT;
 374                         break;
 375                 case LINK_RESET_EVT:
 376                         l->state = LINK_RESET;
 377                         break;
 378                 case LINK_ESTABLISH_EVT:
 379                 case LINK_SYNCH_BEGIN_EVT:
 380                         break;
 381                 case LINK_SYNCH_END_EVT:
 382                         l->state = LINK_ESTABLISHED;
 383                         break;
 384                 case LINK_FAILOVER_BEGIN_EVT:
 385                 case LINK_FAILOVER_END_EVT:
 386                 default:
 387                         goto illegal_evt;
 388                 }
 389                 break;
 390         default:
 391                 pr_err("Unknown FSM state %x in %s\n", l->state, l->name);
 392         }
 393         return rc;
 394 illegal_evt:
 395         pr_err("Illegal FSM event %x in state %x on link %s\n",
 396                evt, l->state, l->name);
 397         return rc;
 398 }
 399
 400 /* link_profile_stats - update statistical profiling of traffic
 401  */
 402 static void link_profile_stats(struct tipc_link *l)
 403 {
 404         struct sk_buff *skb;
 405         struct tipc_msg *msg;
 406         int length;
 407
 408         /* Update counters used in statistical profiling of send traffic */
 409         l->stats.accu_queue_sz += skb_queue_len(&l->transmq);
 410         l->stats.queue_sz_counts++;
 411
 412         skb = skb_peek(&l->transmq);
 413         if (!skb)
 414                 return;
 415         msg = buf_msg(skb);
 416         length = msg_size(msg);
 417
 418         if (msg_user(msg) == MSG_FRAGMENTER) {
 419                 if (msg_type(msg) != FIRST_FRAGMENT)
 420                         return;
 421                 length = msg_size(msg_get_wrapped(msg));
 422         }
 423         l->stats.msg_lengths_total += length;
 424         l->stats.msg_length_counts++;
 425         if (length <= 64)
 426                 l->stats.msg_length_profile[0]++;
 427         else if (length <= 256)
 428                 l->stats.msg_length_profile[1]++;
 429         else if (length <= 1024)
 430                 l->stats.msg_length_profile[2]++;
 431         else if (length <= 4096)
 432                 l->stats.msg_length_profile[3]++;
 433         else if (length <= 16384)
 434                 l->stats.msg_length_profile[4]++;
 435         else if (length <= 32768)
 436                 l->stats.msg_length_profile[5]++;
 437         else
 438                 l->stats.msg_length_profile[6]++;
 439 }
 440
 441 /* tipc_link_timeout - perform periodic task as instructed from node timeout
 442  */
 443 int tipc_link_timeout(struct tipc_link *l, struct sk_buff_head *xmitq)
 444 {
 445         int rc = 0;
 446         int mtyp = STATE_MSG;
 447         bool xmit = false;
 448         bool prb = false;
 449
 450         link_profile_stats(l);
 451
 452         switch (l->state) {
 453         case LINK_ESTABLISHED:
 454         case LINK_SYNCHING:
 455                 if (!l->silent_intv_cnt) {
 456                         if (tipc_bclink_acks_missing(l->owner))
 457                                 xmit = true;
 458                 } else if (l->silent_intv_cnt <= l->abort_limit) {
 459                         xmit = true;
 460                         prb = true;
 461                 } else {
 462                         rc |= tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
 463                 }
 464                 l->silent_intv_cnt++;
 465                 break;
 466         case LINK_RESET:
 467                 xmit = true;
 468                 mtyp = RESET_MSG;
 469                 break;
 470         case LINK_ESTABLISHING:
 471                 xmit = true;
 472                 mtyp = ACTIVATE_MSG;
 473                 break;
 474         case LINK_PEER_RESET:
 475         case LINK_RESETTING:
 476         case LINK_FAILINGOVER:
 477                 break;
 478         default:
 479                 break;
 480         }
 481
 482         if (xmit)
 483                 tipc_link_build_proto_msg(l, mtyp, prb, 0, 0, 0, xmitq);
 484
 485         return rc;
 486 }
 487
 488 /**
 489  * link_schedule_user - schedule a message sender for wakeup after congestion
 490  * @link: congested link
 491  * @list: message that was attempted sent
 492  * Create pseudo msg to send back to user when congestion abates
 493  * Does not consume buffer list
 494  */
 495 static int link_schedule_user(struct tipc_link *link, struct sk_buff_head *list)
 496 {
 497         struct tipc_msg *msg = buf_msg(skb_peek(list));
 498         int imp = msg_importance(msg);
 499         u32 oport = msg_origport(msg);
 500         u32 addr = link_own_addr(link);
 501         struct sk_buff *skb;
 502
 503         /* This really cannot happen...  */
 504         if (unlikely(imp > TIPC_CRITICAL_IMPORTANCE)) {
 505                 pr_warn("%s<%s>, send queue full", link_rst_msg, link->name);
 506                 return -ENOBUFS;
 507         }
 508         /* Non-blocking sender: */
 509         if (TIPC_SKB_CB(skb_peek(list))->wakeup_pending)
 510                 return -ELINKCONG;
 511
 512         /* Create and schedule wakeup pseudo message */
 513         skb = tipc_msg_create(SOCK_WAKEUP, 0, INT_H_SIZE, 0,
 514                               addr, addr, oport, 0, 0);
 515         if (!skb)
 516                 return -ENOBUFS;
 517         TIPC_SKB_CB(skb)->chain_sz = skb_queue_len(list);
 518         TIPC_SKB_CB(skb)->chain_imp = imp;
 519         skb_queue_tail(&link->wakeupq, skb);
 520         link->stats.link_congs++;
 521         return -ELINKCONG;
 522 }
 523
 524 /**
 525  * link_prepare_wakeup - prepare users for wakeup after congestion
 526  * @link: congested link
 527  * Move a number of waiting users, as permitted by available space in
 528  * the send queue, from link wait queue to node wait queue for wakeup
 529  */
 530 void link_prepare_wakeup(struct tipc_link *l)
 531 {
 532         int pnd[TIPC_SYSTEM_IMPORTANCE + 1] = {0,};
 533         int imp, lim;
 534         struct sk_buff *skb, *tmp;
 535
 536         skb_queue_walk_safe(&l->wakeupq, skb, tmp) {
 537                 imp = TIPC_SKB_CB(skb)->chain_imp;
 538                 lim = l->window + l->backlog[imp].limit;
 539                 pnd[imp] += TIPC_SKB_CB(skb)->chain_sz;
 540                 if ((pnd[imp] + l->backlog[imp].len) >= lim)
 541                         break;
 542                 skb_unlink(skb, &l->wakeupq);
 543                 skb_queue_tail(l->inputq, skb);
 544         }
 545 }
 546
 547 /**
 548  * tipc_link_reset_fragments - purge link's inbound message fragments queue
 549  * @l_ptr: pointer to link
 550  */
 551 void tipc_link_reset_fragments(struct tipc_link *l_ptr)
 552 {
 553         kfree_skb(l_ptr->reasm_buf);
 554         l_ptr->reasm_buf = NULL;
 555 }
 556
 557 void tipc_link_purge_backlog(struct tipc_link *l)
 558 {
 559         __skb_queue_purge(&l->backlogq);
 560         l->backlog[TIPC_LOW_IMPORTANCE].len = 0;
 561         l->backlog[TIPC_MEDIUM_IMPORTANCE].len = 0;
 562         l->backlog[TIPC_HIGH_IMPORTANCE].len = 0;
 563         l->backlog[TIPC_CRITICAL_IMPORTANCE].len = 0;
 564         l->backlog[TIPC_SYSTEM_IMPORTANCE].len = 0;
 565 }
 566
 567 /**
 568  * tipc_link_purge_queues - purge all pkt queues associated with link
 569  * @l_ptr: pointer to link
 570  */
 571 void tipc_link_purge_queues(struct tipc_link *l_ptr)
 572 {
 573         __skb_queue_purge(&l_ptr->deferdq);
 574         __skb_queue_purge(&l_ptr->transmq);
 575         tipc_link_purge_backlog(l_ptr);
 576         tipc_link_reset_fragments(l_ptr);
 577 }
 578
 579 void tipc_link_reset(struct tipc_link *l)
 580 {
 581         tipc_link_fsm_evt(l, LINK_RESET_EVT);
 582
 583         /* Link is down, accept any session */
 584         l->peer_session = WILDCARD_SESSION;
 585
 586         /* If peer is up, it only accepts an incremented session number */
 587         msg_set_session(l->pmsg, msg_session(l->pmsg) + 1);
 588
 589         /* Prepare for renewed mtu size negotiation */
 590         l->mtu = l->advertised_mtu;
 591
 592         /* Clean up all queues: */
 593         __skb_queue_purge(&l->transmq);
 594         __skb_queue_purge(&l->deferdq);
 595         skb_queue_splice_init(&l->wakeupq, l->inputq);
 596
 597         tipc_link_purge_backlog(l);
 598         kfree_skb(l->reasm_buf);
 599         kfree_skb(l->failover_reasm_skb);
 600         l->reasm_buf = NULL;
 601         l->failover_reasm_skb = NULL;
 602         l->rcv_unacked = 0;
 603         l->snd_nxt = 1;
 604         l->rcv_nxt = 1;
 605         l->silent_intv_cnt = 0;
 606         l->stats.recv_info = 0;
 607         l->stale_count = 0;
 608         link_reset_statistics(l);
 609 }
 610
 611 /**
 612  * __tipc_link_xmit(): same as tipc_link_xmit, but destlink is known & locked
 613  * @link: link to use
 614  * @list: chain of buffers containing message
 615  *
 616  * Consumes the buffer chain, except when returning an error code,
 617  * Returns 0 if success, or errno: -ELINKCONG, -EMSGSIZE or -ENOBUFS
 618  * Messages at TIPC_SYSTEM_IMPORTANCE are always accepted
 619  */
 620 int __tipc_link_xmit(struct net *net, struct tipc_link *link,
 621                      struct sk_buff_head *list)
 622 {
 623         struct tipc_msg *msg = buf_msg(skb_peek(list));
 624         unsigned int maxwin = link->window;
 625         unsigned int i, imp = msg_importance(msg);
 626         uint mtu = link->mtu;
 627         u16 ack = mod(link->rcv_nxt - 1);
 628         u16 seqno = link->snd_nxt;
 629         u16 bc_last_in = link->owner->bclink.last_in;
 630         struct tipc_media_addr *addr = link->media_addr;
 631         struct sk_buff_head *transmq = &link->transmq;
 632         struct sk_buff_head *backlogq = &link->backlogq;
 633         struct sk_buff *skb, *bskb;
 634
 635         /* Match msg importance against this and all higher backlog limits: */
 636         for (i = imp; i <= TIPC_SYSTEM_IMPORTANCE; i++) {
 637                 if (unlikely(link->backlog[i].len >= link->backlog[i].limit))
 638                         return link_schedule_user(link, list);
 639         }
 640         if (unlikely(msg_size(msg) > mtu))
 641                 return -EMSGSIZE;
 642
 643         /* Prepare each packet for sending, and add to relevant queue: */
 644         while (skb_queue_len(list)) {
 645                 skb = skb_peek(list);
 646                 msg = buf_msg(skb);
 647                 msg_set_seqno(msg, seqno);
 648                 msg_set_ack(msg, ack);
 649                 msg_set_bcast_ack(msg, bc_last_in);
 650
 651                 if (likely(skb_queue_len(transmq) < maxwin)) {
 652                         __skb_dequeue(list);
 653                         __skb_queue_tail(transmq, skb);
 654                         tipc_bearer_send(net, link->bearer_id, skb, addr);
 655                         link->rcv_unacked = 0;
 656                         seqno++;
 657                         continue;
 658                 }
 659                 if (tipc_msg_bundle(skb_peek_tail(backlogq), msg, mtu)) {
 660                         kfree_skb(__skb_dequeue(list));
 661                         link->stats.sent_bundled++;
 662                         continue;
 663                 }
 664                 if (tipc_msg_make_bundle(&bskb, msg, mtu, link->addr)) {
 665                         kfree_skb(__skb_dequeue(list));
 666                         __skb_queue_tail(backlogq, bskb);
 667                         link->backlog[msg_importance(buf_msg(bskb))].len++;
 668                         link->stats.sent_bundled++;
 669                         link->stats.sent_bundles++;
 670                         continue;
 671                 }
 672                 link->backlog[imp].len += skb_queue_len(list);
 673                 skb_queue_splice_tail_init(list, backlogq);
 674         }
 675         link->snd_nxt = seqno;
 676         return 0;
 677 }
 678
 679 /**
 680  * tipc_link_xmit(): enqueue buffer list according to queue situation
 681  * @link: link to use
 682  * @list: chain of buffers containing message
 683  * @xmitq: returned list of packets to be sent by caller
 684  *
 685  * Consumes the buffer chain, except when returning -ELINKCONG,
 686  * since the caller then may want to make more send attempts.
 687  * Returns 0 if success, or errno: -ELINKCONG, -EMSGSIZE or -ENOBUFS
 688  * Messages at TIPC_SYSTEM_IMPORTANCE are always accepted
 689  */
 690 int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *list,
 691                    struct sk_buff_head *xmitq)
 692 {
 693         struct tipc_msg *hdr = buf_msg(skb_peek(list));
 694         unsigned int maxwin = l->window;
 695         unsigned int i, imp = msg_importance(hdr);
 696         unsigned int mtu = l->mtu;
 697         u16 ack = l->rcv_nxt - 1;
 698         u16 seqno = l->snd_nxt;
 699         u16 bc_last_in = l->owner->bclink.last_in;
 700         struct sk_buff_head *transmq = &l->transmq;
 701         struct sk_buff_head *backlogq = &l->backlogq;
 702         struct sk_buff *skb, *_skb, *bskb;
 703
 704         /* Match msg importance against this and all higher backlog limits: */
 705         for (i = imp; i <= TIPC_SYSTEM_IMPORTANCE; i++) {
 706                 if (unlikely(l->backlog[i].len >= l->backlog[i].limit))
 707                         return link_schedule_user(l, list);
 708         }
 709         if (unlikely(msg_size(hdr) > mtu))
 710                 return -EMSGSIZE;
 711
 712         /* Prepare each packet for sending, and add to relevant queue: */
 713         while (skb_queue_len(list)) {
 714                 skb = skb_peek(list);
 715                 hdr = buf_msg(skb);
 716                 msg_set_seqno(hdr, seqno);
 717                 msg_set_ack(hdr, ack);
 718                 msg_set_bcast_ack(hdr, bc_last_in);
 719
 720                 if (likely(skb_queue_len(transmq) < maxwin)) {
 721                         _skb = skb_clone(skb, GFP_ATOMIC);
 722                         if (!_skb)
 723                                 return -ENOBUFS;
 724                         __skb_dequeue(list);
 725                         __skb_queue_tail(transmq, skb);
 726                         __skb_queue_tail(xmitq, _skb);
 727                         l->rcv_unacked = 0;
 728                         seqno++;
 729                         continue;
 730                 }
 731                 if (tipc_msg_bundle(skb_peek_tail(backlogq), hdr, mtu)) {
 732                         kfree_skb(__skb_dequeue(list));
 733                         l->stats.sent_bundled++;
 734                         continue;
 735                 }
 736                 if (tipc_msg_make_bundle(&bskb, hdr, mtu, l->addr)) {
 737                         kfree_skb(__skb_dequeue(list));
 738                         __skb_queue_tail(backlogq, bskb);
 739                         l->backlog[msg_importance(buf_msg(bskb))].len++;
 740                         l->stats.sent_bundled++;
 741                         l->stats.sent_bundles++;
 742                         continue;
 743                 }
 744                 l->backlog[imp].len += skb_queue_len(list);
 745                 skb_queue_splice_tail_init(list, backlogq);
 746         }
 747         l->snd_nxt = seqno;
 748         return 0;
 749 }
 750
 751 /*
 752  * tipc_link_sync_rcv - synchronize broadcast link endpoints.
 753  * Receive the sequence number where we should start receiving and
 754  * acking broadcast packets from a newly added peer node, and open
 755  * up for reception of such packets.
 756  *
 757  * Called with node locked
 758  */
 759 static void tipc_link_sync_rcv(struct tipc_node *n, struct sk_buff *buf)
 760 {
 761         struct tipc_msg *msg = buf_msg(buf);
 762
 763         n->bclink.last_sent = n->bclink.last_in = msg_last_bcast(msg);
 764         n->bclink.recv_permitted = true;
 765         kfree_skb(buf);
 766 }
 767
 768 /*
 769  * tipc_link_push_packets - push unsent packets to bearer
 770  *
 771  * Push out the unsent messages of a link where congestion
 772  * has abated. Node is locked.
 773  *
 774  * Called with node locked
 775  */
 776 void tipc_link_push_packets(struct tipc_link *link)
 777 {
 778         struct sk_buff *skb;
 779         struct tipc_msg *msg;
 780         u16 seqno = link->snd_nxt;
 781         u16 ack = mod(link->rcv_nxt - 1);
 782
 783         while (skb_queue_len(&link->transmq) < link->window) {
 784                 skb = __skb_dequeue(&link->backlogq);
 785                 if (!skb)
 786                         break;
 787                 msg = buf_msg(skb);
 788                 link->backlog[msg_importance(msg)].len--;
 789                 msg_set_ack(msg, ack);
 790                 msg_set_seqno(msg, seqno);
 791                 seqno = mod(seqno + 1);
 792                 msg_set_bcast_ack(msg, link->owner->bclink.last_in);
 793                 link->rcv_unacked = 0;
 794                 __skb_queue_tail(&link->transmq, skb);
 795                 tipc_bearer_send(link->owner->net, link->bearer_id,
 796                                  skb, link->media_addr);
 797         }
 798         link->snd_nxt = seqno;
 799 }
 800
 801 void tipc_link_advance_backlog(struct tipc_link *l, struct sk_buff_head *xmitq)
 802 {
 803         struct sk_buff *skb, *_skb;
 804         struct tipc_msg *hdr;
 805         u16 seqno = l->snd_nxt;
 806         u16 ack = l->rcv_nxt - 1;
 807
 808         while (skb_queue_len(&l->transmq) < l->window) {
 809                 skb = skb_peek(&l->backlogq);
 810                 if (!skb)
 811                         break;
 812                 _skb = skb_clone(skb, GFP_ATOMIC);
 813                 if (!_skb)
 814                         break;
 815                 __skb_dequeue(&l->backlogq);
 816                 hdr = buf_msg(skb);
 817                 l->backlog[msg_importance(hdr)].len--;
 818                 __skb_queue_tail(&l->transmq, skb);
 819                 __skb_queue_tail(xmitq, _skb);
 820                 msg_set_ack(hdr, ack);
 821                 msg_set_seqno(hdr, seqno);
 822                 msg_set_bcast_ack(hdr, l->owner->bclink.last_in);
 823                 l->rcv_unacked = 0;
 824                 seqno++;
 825         }
 826         l->snd_nxt = seqno;
 827 }
 828
 829 static void link_retransmit_failure(struct tipc_link *l_ptr,
 830                                     struct sk_buff *buf)
 831 {
 832         struct tipc_msg *msg = buf_msg(buf);
 833         struct net *net = l_ptr->owner->net;
 834
 835         pr_warn("Retransmission failure on link <%s>\n", l_ptr->name);
 836
 837         if (l_ptr->addr) {
 838                 /* Handle failure on standard link */
 839                 link_print(l_ptr, "Resetting link ");
 840                 pr_info("Failed msg: usr %u, typ %u, len %u, err %u\n",
 841                         msg_user(msg), msg_type(msg), msg_size(msg),
 842                         msg_errcode(msg));
 843                 pr_info("sqno %u, prev: %x, src: %x\n",
 844                         msg_seqno(msg), msg_prevnode(msg), msg_orignode(msg));
 845         } else {
 846                 /* Handle failure on broadcast link */
 847                 struct tipc_node *n_ptr;
 848                 char addr_string[16];
 849
 850                 pr_info("Msg seq number: %u,  ", msg_seqno(msg));
 851                 pr_cont("Outstanding acks: %lu\n",
 852                         (unsigned long) TIPC_SKB_CB(buf)->handle);
 853
 854                 n_ptr = tipc_bclink_retransmit_to(net);
 855
 856                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 857                 pr_info("Broadcast link info for %s\n", addr_string);
 858                 pr_info("Reception permitted: %d,  Acked: %u\n",
 859                         n_ptr->bclink.recv_permitted,
 860                         n_ptr->bclink.acked);
 861                 pr_info("Last in: %u,  Oos state: %u,  Last sent: %u\n",
 862                         n_ptr->bclink.last_in,
 863                         n_ptr->bclink.oos_state,
 864                         n_ptr->bclink.last_sent);
 865
 866                 n_ptr->action_flags |= TIPC_BCAST_RESET;
 867                 l_ptr->stale_count = 0;
 868         }
 869 }
 870
 871 void tipc_link_retransmit(struct tipc_link *l_ptr, struct sk_buff *skb,
 872                           u32 retransmits)
 873 {
 874         struct tipc_msg *msg;
 875
 876         if (!skb)
 877                 return;
 878
 879         msg = buf_msg(skb);
 880
 881         /* Detect repeated retransmit failures */
 882         if (l_ptr->last_retransm == msg_seqno(msg)) {
 883                 if (++l_ptr->stale_count > 100) {
 884                         link_retransmit_failure(l_ptr, skb);
 885                         return;
 886                 }
 887         } else {
 888                 l_ptr->last_retransm = msg_seqno(msg);
 889                 l_ptr->stale_count = 1;
 890         }
 891
 892         skb_queue_walk_from(&l_ptr->transmq, skb) {
 893                 if (!retransmits)
 894                         break;
 895                 msg = buf_msg(skb);
 896                 msg_set_ack(msg, mod(l_ptr->rcv_nxt - 1));
 897                 msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
 898                 tipc_bearer_send(l_ptr->owner->net, l_ptr->bearer_id, skb,
 899                                  l_ptr->media_addr);
 900                 retransmits--;
 901                 l_ptr->stats.retransmitted++;
 902         }
 903 }
 904
 905 static int tipc_link_retransm(struct tipc_link *l, int retransm,
 906                               struct sk_buff_head *xmitq)
 907 {
 908         struct sk_buff *_skb, *skb = skb_peek(&l->transmq);
 909         struct tipc_msg *hdr;
 910
 911         if (!skb)
 912                 return 0;
 913
 914         /* Detect repeated retransmit failures on same packet */
 915         if (likely(l->last_retransm != buf_seqno(skb))) {
 916                 l->last_retransm = buf_seqno(skb);
 917                 l->stale_count = 1;
 918         } else if (++l->stale_count > 100) {
 919                 link_retransmit_failure(l, skb);
 920                 return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
 921         }
 922         skb_queue_walk(&l->transmq, skb) {
 923                 if (!retransm)
 924                         return 0;
 925                 hdr = buf_msg(skb);
 926                 _skb = __pskb_copy(skb, MIN_H_SIZE, GFP_ATOMIC);
 927                 if (!_skb)
 928                         return 0;
 929                 hdr = buf_msg(_skb);
 930                 msg_set_ack(hdr, l->rcv_nxt - 1);
 931                 msg_set_bcast_ack(hdr, l->owner->bclink.last_in);
 932                 _skb->priority = TC_PRIO_CONTROL;
 933                 __skb_queue_tail(xmitq, _skb);
 934                 retransm--;
 935                 l->stats.retransmitted++;
 936         }
 937         return 0;
 938 }
 939
 940 /* tipc_data_input - deliver data and name distr msgs to upper layer
 941  *
 942  * Consumes buffer if message is of right type
 943  * Node lock must be held
 944  */
 945 static bool tipc_data_input(struct tipc_link *link, struct sk_buff *skb,
 946                             struct sk_buff_head *inputq)
 947 {
 948         struct tipc_node *node = link->owner;
 949
 950         switch (msg_user(buf_msg(skb))) {
 951         case TIPC_LOW_IMPORTANCE:
 952         case TIPC_MEDIUM_IMPORTANCE:
 953         case TIPC_HIGH_IMPORTANCE:
 954         case TIPC_CRITICAL_IMPORTANCE:
 955         case CONN_MANAGER:
 956                 __skb_queue_tail(inputq, skb);
 957                 return true;
 958         case NAME_DISTRIBUTOR:
 959                 node->bclink.recv_permitted = true;
 960                 skb_queue_tail(link->namedq, skb);
 961                 return true;
 962         case MSG_BUNDLER:
 963         case TUNNEL_PROTOCOL:
 964         case MSG_FRAGMENTER:
 965         case BCAST_PROTOCOL:
 966                 return false;
 967         default:
 968                 pr_warn("Dropping received illegal msg type\n");
 969                 kfree_skb(skb);
 970                 return false;
 971         };
 972 }
 973
 974 /* tipc_link_input - process packet that has passed link protocol check
 975  *
 976  * Consumes buffer
 977  */
 978 static int tipc_link_input(struct tipc_link *l, struct sk_buff *skb,
 979                            struct sk_buff_head *inputq)
 980 {
 981         struct tipc_node *node = l->owner;
 982         struct tipc_msg *hdr = buf_msg(skb);
 983         struct sk_buff **reasm_skb = &l->reasm_buf;
 984         struct sk_buff *iskb;
 985         int usr = msg_user(hdr);
 986         int rc = 0;
 987         int pos = 0;
 988         int ipos = 0;
 989
 990         if (unlikely(usr == TUNNEL_PROTOCOL)) {
 991                 if (msg_type(hdr) == SYNCH_MSG) {
 992                         __skb_queue_purge(&l->deferdq);
 993                         goto drop;
 994                 }
 995                 if (!tipc_msg_extract(skb, &iskb, &ipos))
 996                         return rc;
 997                 kfree_skb(skb);
 998                 skb = iskb;
 999                 hdr = buf_msg(skb);
1000                 if (less(msg_seqno(hdr), l->drop_point))
1001                         goto drop;
1002                 if (tipc_data_input(l, skb, inputq))
1003                         return rc;
1004                 usr = msg_user(hdr);
1005                 reasm_skb = &l->failover_reasm_skb;
1006         }
1007
1008         if (usr == MSG_BUNDLER) {
1009                 l->stats.recv_bundles++;
1010                 l->stats.recv_bundled += msg_msgcnt(hdr);
1011                 while (tipc_msg_extract(skb, &iskb, &pos))
1012                         tipc_data_input(l, iskb, inputq);
1013                 return 0;
1014         } else if (usr == MSG_FRAGMENTER) {
1015                 l->stats.recv_fragments++;
1016                 if (tipc_buf_append(reasm_skb, &skb)) {
1017                         l->stats.recv_fragmented++;
1018                         tipc_data_input(l, skb, inputq);
1019                 } else if (!*reasm_skb) {
1020                         return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1021                 }
1022                 return 0;
1023         } else if (usr == BCAST_PROTOCOL) {
1024                 tipc_link_sync_rcv(node, skb);
1025                 return 0;
1026         }
1027 drop:
1028         kfree_skb(skb);
1029         return 0;
1030 }
1031
1032 static bool tipc_link_release_pkts(struct tipc_link *l, u16 acked)
1033 {
1034         bool released = false;
1035         struct sk_buff *skb, *tmp;
1036
1037         skb_queue_walk_safe(&l->transmq, skb, tmp) {
1038                 if (more(buf_seqno(skb), acked))
1039                         break;
1040                 __skb_unlink(skb, &l->transmq);
1041                 kfree_skb(skb);
1042                 released = true;
1043         }
1044         return released;
1045 }
1046
1047 /* tipc_link_rcv - process TIPC packets/messages arriving from off-node
1048  * @link: the link that should handle the message
1049  * @skb: TIPC packet
1050  * @xmitq: queue to place packets to be sent after this call
1051  */
1052 int tipc_link_rcv(struct tipc_link *l, struct sk_buff *skb,
1053                   struct sk_buff_head *xmitq)
1054 {
1055         struct sk_buff_head *arrvq = &l->deferdq;
1056         struct sk_buff_head tmpq;
1057         struct tipc_msg *hdr;
1058         u16 seqno, rcv_nxt;
1059         int rc = 0;
1060
1061         __skb_queue_head_init(&tmpq);
1062
1063         if (unlikely(!__tipc_skb_queue_sorted(arrvq, skb))) {
1064                 if (!(skb_queue_len(arrvq) % TIPC_NACK_INTV))
1065                         tipc_link_build_proto_msg(l, STATE_MSG, 0,
1066                                                   0, 0, 0, xmitq);
1067                 return rc;
1068         }
1069
1070         while ((skb = skb_peek(arrvq))) {
1071                 hdr = buf_msg(skb);
1072
1073                 /* Verify and update link state */
1074                 if (unlikely(msg_user(hdr) == LINK_PROTOCOL)) {
1075                         __skb_dequeue(arrvq);
1076                         rc = tipc_link_proto_rcv(l, skb, xmitq);
1077                         continue;
1078                 }
1079
1080                 if (unlikely(!link_is_up(l))) {
1081                         rc = tipc_link_fsm_evt(l, LINK_ESTABLISH_EVT);
1082                         if (!link_is_up(l)) {
1083                                 kfree_skb(__skb_dequeue(arrvq));
1084                                 goto exit;
1085                         }
1086                 }
1087
1088                 l->silent_intv_cnt = 0;
1089
1090                 /* Forward queues and wake up waiting users */
1091                 if (likely(tipc_link_release_pkts(l, msg_ack(hdr)))) {
1092                         tipc_link_advance_backlog(l, xmitq);
1093                         if (unlikely(!skb_queue_empty(&l->wakeupq)))
1094                                 link_prepare_wakeup(l);
1095                 }
1096
1097                 /* Defer reception if there is a gap in the sequence */
1098                 seqno = msg_seqno(hdr);
1099                 rcv_nxt = l->rcv_nxt;
1100                 if (unlikely(less(rcv_nxt, seqno))) {
1101                         l->stats.deferred_recv++;
1102                         goto exit;
1103                 }
1104
1105                 __skb_dequeue(arrvq);
1106
1107                 /* Drop if packet already received */
1108                 if (unlikely(more(rcv_nxt, seqno))) {
1109                         l->stats.duplicates++;
1110                         kfree_skb(skb);
1111                         goto exit;
1112                 }
1113
1114                 /* Packet can be delivered */
1115                 l->rcv_nxt++;
1116                 l->stats.recv_info++;
1117                 if (unlikely(!tipc_data_input(l, skb, &tmpq)))
1118                         rc = tipc_link_input(l, skb, &tmpq);
1119
1120                 /* Ack at regular intervals */
1121                 if (unlikely(++l->rcv_unacked >= TIPC_MIN_LINK_WIN)) {
1122                         l->rcv_unacked = 0;
1123                         l->stats.sent_acks++;
1124                         tipc_link_build_proto_msg(l, STATE_MSG,
1125                                                   0, 0, 0, 0, xmitq);
1126                 }
1127         }
1128 exit:
1129         tipc_skb_queue_splice_tail(&tmpq, l->inputq);
1130         return rc;
1131 }
1132
1133 /**
1134  * tipc_link_defer_pkt - Add out-of-sequence message to deferred reception queue
1135  *
1136  * Returns increase in queue length (i.e. 0 or 1)
1137  */
1138 u32 tipc_link_defer_pkt(struct sk_buff_head *list, struct sk_buff *skb)
1139 {
1140         struct sk_buff *skb1;
1141         u16 seq_no = buf_seqno(skb);
1142
1143         /* Empty queue ? */
1144         if (skb_queue_empty(list)) {
1145                 __skb_queue_tail(list, skb);
1146                 return 1;
1147         }
1148
1149         /* Last ? */
1150         if (less(buf_seqno(skb_peek_tail(list)), seq_no)) {
1151                 __skb_queue_tail(list, skb);
1152                 return 1;
1153         }
1154
1155         /* Locate insertion point in queue, then insert; discard if duplicate */
1156         skb_queue_walk(list, skb1) {
1157                 u16 curr_seqno = buf_seqno(skb1);
1158
1159                 if (seq_no == curr_seqno) {
1160                         kfree_skb(skb);
1161                         return 0;
1162                 }
1163
1164                 if (less(seq_no, curr_seqno))
1165                         break;
1166         }
1167
1168         __skb_queue_before(list, skb1, skb);
1169         return 1;
1170 }
1171
1172 /*
1173  * Send protocol message to the other endpoint.
1174  */
1175 void tipc_link_proto_xmit(struct tipc_link *l, u32 msg_typ, int probe_msg,
1176                           u32 gap, u32 tolerance, u32 priority)
1177 {
1178         struct sk_buff *skb = NULL;
1179         struct sk_buff_head xmitq;
1180
1181         __skb_queue_head_init(&xmitq);
1182         tipc_link_build_proto_msg(l, msg_typ, probe_msg, gap,
1183                                   tolerance, priority, &xmitq);
1184         skb = __skb_dequeue(&xmitq);
1185         if (!skb)
1186                 return;
1187         tipc_bearer_send(l->owner->net, l->bearer_id, skb, l->media_addr);
1188         l->rcv_unacked = 0;
1189         kfree_skb(skb);
1190 }
1191
1192 /* tipc_link_build_proto_msg: prepare link protocol message for transmission
1193  */
1194 static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
1195                                       u16 rcvgap, int tolerance, int priority,
1196                                       struct sk_buff_head *xmitq)
1197 {
1198         struct sk_buff *skb = NULL;
1199         struct tipc_msg *hdr = l->pmsg;
1200         u16 snd_nxt = l->snd_nxt;
1201         u16 rcv_nxt = l->rcv_nxt;
1202         u16 rcv_last = rcv_nxt - 1;
1203         int node_up = l->owner->bclink.recv_permitted;
1204
1205         /* Don't send protocol message during reset or link failover */
1206         if (tipc_link_is_blocked(l))
1207                 return;
1208
1209         msg_set_type(hdr, mtyp);
1210         msg_set_net_plane(hdr, l->net_plane);
1211         msg_set_bcast_ack(hdr, l->owner->bclink.last_in);
1212         msg_set_last_bcast(hdr, tipc_bclink_get_last_sent(l->owner->net));
1213         msg_set_link_tolerance(hdr, tolerance);
1214         msg_set_linkprio(hdr, priority);
1215         msg_set_redundant_link(hdr, node_up);
1216         msg_set_seq_gap(hdr, 0);
1217
1218         /* Compatibility: created msg must not be in sequence with pkt flow */
1219         msg_set_seqno(hdr, snd_nxt + U16_MAX / 2);
1220
1221         if (mtyp == STATE_MSG) {
1222                 if (!tipc_link_is_up(l))
1223                         return;
1224                 msg_set_next_sent(hdr, snd_nxt);
1225
1226                 /* Override rcvgap if there are packets in deferred queue */
1227                 if (!skb_queue_empty(&l->deferdq))
1228                         rcvgap = buf_seqno(skb_peek(&l->deferdq)) - rcv_nxt;
1229                 if (rcvgap) {
1230                         msg_set_seq_gap(hdr, rcvgap);
1231                         l->stats.sent_nacks++;
1232                 }
1233                 msg_set_ack(hdr, rcv_last);
1234                 msg_set_probe(hdr, probe);
1235                 if (probe)
1236                         l->stats.sent_probes++;
1237                 l->stats.sent_states++;
1238         } else {
1239                 /* RESET_MSG or ACTIVATE_MSG */
1240                 msg_set_max_pkt(hdr, l->advertised_mtu);
1241                 msg_set_ack(hdr, l->rcv_nxt - 1);
1242                 msg_set_next_sent(hdr, 1);
1243         }
1244         skb = tipc_buf_acquire(msg_size(hdr));
1245         if (!skb)
1246                 return;
1247         skb_copy_to_linear_data(skb, hdr, msg_size(hdr));
1248         skb->priority = TC_PRIO_CONTROL;
1249         __skb_queue_tail(xmitq, skb);
1250 }
1251
1252 /* tipc_link_tnl_prepare(): prepare and return a list of tunnel packets
1253  * with contents of the link's tranmsit and backlog queues.
1254  */
1255 void tipc_link_tnl_prepare(struct tipc_link *l, struct tipc_link *tnl,
1256                            int mtyp, struct sk_buff_head *xmitq)
1257 {
1258         struct sk_buff *skb, *tnlskb;
1259         struct tipc_msg *hdr, tnlhdr;
1260         struct sk_buff_head *queue = &l->transmq;
1261         struct sk_buff_head tmpxq, tnlq;
1262         u16 pktlen, pktcnt, seqno = l->snd_nxt;
1263
1264         if (!tnl)
1265                 return;
1266
1267         skb_queue_head_init(&tnlq);
1268         skb_queue_head_init(&tmpxq);
1269
1270         /* At least one packet required for safe algorithm => add dummy */
1271         skb = tipc_msg_create(TIPC_LOW_IMPORTANCE, TIPC_DIRECT_MSG,
1272                               BASIC_H_SIZE, 0, l->addr, link_own_addr(l),
1273                               0, 0, TIPC_ERR_NO_PORT);
1274         if (!skb) {
1275                 pr_warn("%sunable to create tunnel packet\n", link_co_err);
1276                 return;
1277         }
1278         skb_queue_tail(&tnlq, skb);
1279         tipc_link_xmit(l, &tnlq, &tmpxq);
1280         __skb_queue_purge(&tmpxq);
1281
1282         /* Initialize reusable tunnel packet header */
1283         tipc_msg_init(link_own_addr(l), &tnlhdr, TUNNEL_PROTOCOL,
1284                       mtyp, INT_H_SIZE, l->addr);
1285         pktcnt = skb_queue_len(&l->transmq) + skb_queue_len(&l->backlogq);
1286         msg_set_msgcnt(&tnlhdr, pktcnt);
1287         msg_set_bearer_id(&tnlhdr, l->peer_bearer_id);
1288 tnl:
1289         /* Wrap each packet into a tunnel packet */
1290         skb_queue_walk(queue, skb) {
1291                 hdr = buf_msg(skb);
1292                 if (queue == &l->backlogq)
1293                         msg_set_seqno(hdr, seqno++);
1294                 pktlen = msg_size(hdr);
1295                 msg_set_size(&tnlhdr, pktlen + INT_H_SIZE);
1296                 tnlskb = tipc_buf_acquire(pktlen + INT_H_SIZE);
1297                 if (!tnlskb) {
1298                         pr_warn("%sunable to send packet\n", link_co_err);
1299                         return;
1300                 }
1301                 skb_copy_to_linear_data(tnlskb, &tnlhdr, INT_H_SIZE);
1302                 skb_copy_to_linear_data_offset(tnlskb, INT_H_SIZE, hdr, pktlen);
1303                 __skb_queue_tail(&tnlq, tnlskb);
1304         }
1305         if (queue != &l->backlogq) {
1306                 queue = &l->backlogq;
1307                 goto tnl;
1308         }
1309
1310         tipc_link_xmit(tnl, &tnlq, xmitq);
1311
1312         if (mtyp == FAILOVER_MSG) {
1313                 tnl->drop_point = l->rcv_nxt;
1314                 tnl->failover_reasm_skb = l->reasm_buf;
1315                 l->reasm_buf = NULL;
1316         }
1317 }
1318
1319 /* tipc_link_proto_rcv(): receive link level protocol message :
1320  * Note that network plane id propagates through the network, and may
1321  * change at any time. The node with lowest numerical id determines
1322  * network plane
1323  */
1324 static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
1325                                struct sk_buff_head *xmitq)
1326 {
1327         struct tipc_msg *hdr = buf_msg(skb);
1328         u16 rcvgap = 0;
1329         u16 nacked_gap = msg_seq_gap(hdr);
1330         u16 peers_snd_nxt =  msg_next_sent(hdr);
1331         u16 peers_tol = msg_link_tolerance(hdr);
1332         u16 peers_prio = msg_linkprio(hdr);
1333         u16 rcv_nxt = l->rcv_nxt;
1334         char *if_name;
1335         int rc = 0;
1336
1337         if (tipc_link_is_blocked(l))
1338                 goto exit;
1339
1340         if (link_own_addr(l) > msg_prevnode(hdr))
1341                 l->net_plane = msg_net_plane(hdr);
1342
1343         switch (msg_type(hdr)) {
1344         case RESET_MSG:
1345
1346                 /* Ignore duplicate RESET with old session number */
1347                 if ((less_eq(msg_session(hdr), l->peer_session)) &&
1348                     (l->peer_session != WILDCARD_SESSION))
1349                         break;
1350                 /* fall thru' */
1351
1352         case ACTIVATE_MSG:
1353
1354                 /* Complete own link name with peer's interface name */
1355                 if_name =  strrchr(l->name, ':') + 1;
1356                 if (sizeof(l->name) - (if_name - l->name) <= TIPC_MAX_IF_NAME)
1357                         break;
1358                 if (msg_data_sz(hdr) < TIPC_MAX_IF_NAME)
1359                         break;
1360                 strncpy(if_name, msg_data(hdr), TIPC_MAX_IF_NAME);
1361
1362                 /* Update own tolerance if peer indicates a non-zero value */
1363                 if (in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL))
1364                         l->tolerance = peers_tol;
1365
1366                 /* Update own priority if peer's priority is higher */
1367                 if (in_range(peers_prio, l->priority + 1, TIPC_MAX_LINK_PRI))
1368                         l->priority = peers_prio;
1369
1370                 if (msg_type(hdr) == RESET_MSG) {
1371                         rc |= tipc_link_fsm_evt(l, LINK_PEER_RESET_EVT);
1372                 } else if (!link_is_up(l)) {
1373                         tipc_link_fsm_evt(l, LINK_PEER_RESET_EVT);
1374                         rc |= tipc_link_fsm_evt(l, LINK_ESTABLISH_EVT);
1375                 }
1376                 l->peer_session = msg_session(hdr);
1377                 l->peer_bearer_id = msg_bearer_id(hdr);
1378                 if (l->mtu > msg_max_pkt(hdr))
1379                         l->mtu = msg_max_pkt(hdr);
1380                 break;
1381
1382         case STATE_MSG:
1383
1384                 /* Update own tolerance if peer indicates a non-zero value */
1385                 if (in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL))
1386                         l->tolerance = peers_tol;
1387
1388                 l->silent_intv_cnt = 0;
1389                 l->stats.recv_states++;
1390                 if (msg_probe(hdr))
1391                         l->stats.recv_probes++;
1392                 rc = tipc_link_fsm_evt(l, LINK_ESTABLISH_EVT);
1393                 if (!link_is_up(l))
1394                         break;
1395
1396                 /* Send NACK if peer has sent pkts we haven't received yet */
1397                 if (more(peers_snd_nxt, rcv_nxt) && !tipc_link_is_synching(l))
1398                         rcvgap = peers_snd_nxt - l->rcv_nxt;
1399                 if (rcvgap || (msg_probe(hdr)))
1400                         tipc_link_build_proto_msg(l, STATE_MSG, 0, rcvgap,
1401                                                   0, 0, xmitq);
1402                 tipc_link_release_pkts(l, msg_ack(hdr));
1403
1404                 /* If NACK, retransmit will now start at right position */
1405                 if (nacked_gap) {
1406                         rc = tipc_link_retransm(l, nacked_gap, xmitq);
1407                         l->stats.recv_nacks++;
1408                 }
1409
1410                 tipc_link_advance_backlog(l, xmitq);
1411                 if (unlikely(!skb_queue_empty(&l->wakeupq)))
1412                         link_prepare_wakeup(l);
1413         }
1414 exit:
1415         kfree_skb(skb);
1416         return rc;
1417 }
1418
1419 void tipc_link_set_queue_limits(struct tipc_link *l, u32 win)
1420 {
1421         int max_bulk = TIPC_MAX_PUBLICATIONS / (l->mtu / ITEM_SIZE);
1422
1423         l->window = win;
1424         l->backlog[TIPC_LOW_IMPORTANCE].limit      = win / 2;
1425         l->backlog[TIPC_MEDIUM_IMPORTANCE].limit   = win;
1426         l->backlog[TIPC_HIGH_IMPORTANCE].limit     = win / 2 * 3;
1427         l->backlog[TIPC_CRITICAL_IMPORTANCE].limit = win * 2;
1428         l->backlog[TIPC_SYSTEM_IMPORTANCE].limit   = max_bulk;
1429 }
1430
1431 /* tipc_link_find_owner - locate owner node of link by link's name
1432  * @net: the applicable net namespace
1433  * @name: pointer to link name string
1434  * @bearer_id: pointer to index in 'node->links' array where the link was found.
1435  *
1436  * Returns pointer to node owning the link, or 0 if no matching link is found.
1437  */
1438 static struct tipc_node *tipc_link_find_owner(struct net *net,
1439                                               const char *link_name,
1440                                               unsigned int *bearer_id)
1441 {
1442         struct tipc_net *tn = net_generic(net, tipc_net_id);
1443         struct tipc_link *l_ptr;
1444         struct tipc_node *n_ptr;
1445         struct tipc_node *found_node = NULL;
1446         int i;
1447
1448         *bearer_id = 0;
1449         rcu_read_lock();
1450         list_for_each_entry_rcu(n_ptr, &tn->node_list, list) {
1451                 tipc_node_lock(n_ptr);
1452                 for (i = 0; i < MAX_BEARERS; i++) {
1453                         l_ptr = n_ptr->links[i].link;
1454                         if (l_ptr && !strcmp(l_ptr->name, link_name)) {
1455                                 *bearer_id = i;
1456                                 found_node = n_ptr;
1457                                 break;
1458                         }
1459                 }
1460                 tipc_node_unlock(n_ptr);
1461                 if (found_node)
1462                         break;
1463         }
1464         rcu_read_unlock();
1465
1466         return found_node;
1467 }
1468
1469 /**
1470  * link_reset_statistics - reset link statistics
1471  * @l_ptr: pointer to link
1472  */
1473 static void link_reset_statistics(struct tipc_link *l_ptr)
1474 {
1475         memset(&l_ptr->stats, 0, sizeof(l_ptr->stats));
1476         l_ptr->stats.sent_info = l_ptr->snd_nxt;
1477         l_ptr->stats.recv_info = l_ptr->rcv_nxt;
1478 }
1479
1480 static void link_print(struct tipc_link *l, const char *str)
1481 {
1482         struct sk_buff *hskb = skb_peek(&l->transmq);
1483         u16 head = hskb ? msg_seqno(buf_msg(hskb)) : l->snd_nxt;
1484         u16 tail = l->snd_nxt - 1;
1485
1486         pr_info("%s Link <%s> state %x\n", str, l->name, l->state);
1487         pr_info("XMTQ: %u [%u-%u], BKLGQ: %u, SNDNX: %u, RCVNX: %u\n",
1488                 skb_queue_len(&l->transmq), head, tail,
1489                 skb_queue_len(&l->backlogq), l->snd_nxt, l->rcv_nxt);
1490 }
1491
1492 /* Parse and validate nested (link) properties valid for media, bearer and link
1493  */
1494 int tipc_nl_parse_link_prop(struct nlattr *prop, struct nlattr *props[])
1495 {
1496         int err;
1497
1498         err = nla_parse_nested(props, TIPC_NLA_PROP_MAX, prop,
1499                                tipc_nl_prop_policy);
1500         if (err)
1501                 return err;
1502
1503         if (props[TIPC_NLA_PROP_PRIO]) {
1504                 u32 prio;
1505
1506                 prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
1507                 if (prio > TIPC_MAX_LINK_PRI)
1508                         return -EINVAL;
1509         }
1510
1511         if (props[TIPC_NLA_PROP_TOL]) {
1512                 u32 tol;
1513
1514                 tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
1515                 if ((tol < TIPC_MIN_LINK_TOL) || (tol > TIPC_MAX_LINK_TOL))
1516                         return -EINVAL;
1517         }
1518
1519         if (props[TIPC_NLA_PROP_WIN]) {
1520                 u32 win;
1521
1522                 win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
1523                 if ((win < TIPC_MIN_LINK_WIN) || (win > TIPC_MAX_LINK_WIN))
1524                         return -EINVAL;
1525         }
1526
1527         return 0;
1528 }
1529
1530 int tipc_nl_link_set(struct sk_buff *skb, struct genl_info *info)
1531 {
1532         int err;
1533         int res = 0;
1534         int bearer_id;
1535         char *name;
1536         struct tipc_link *link;
1537         struct tipc_node *node;
1538         struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
1539         struct net *net = sock_net(skb->sk);
1540
1541         if (!info->attrs[TIPC_NLA_LINK])
1542                 return -EINVAL;
1543
1544         err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
1545                                info->attrs[TIPC_NLA_LINK],
1546                                tipc_nl_link_policy);
1547         if (err)
1548                 return err;
1549
1550         if (!attrs[TIPC_NLA_LINK_NAME])
1551                 return -EINVAL;
1552
1553         name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
1554
1555         if (strcmp(name, tipc_bclink_name) == 0)
1556                 return tipc_nl_bc_link_set(net, attrs);
1557
1558         node = tipc_link_find_owner(net, name, &bearer_id);
1559         if (!node)
1560                 return -EINVAL;
1561
1562         tipc_node_lock(node);
1563
1564         link = node->links[bearer_id].link;
1565         if (!link) {
1566                 res = -EINVAL;
1567                 goto out;
1568         }
1569
1570         if (attrs[TIPC_NLA_LINK_PROP]) {
1571                 struct nlattr *props[TIPC_NLA_PROP_MAX + 1];
1572
1573                 err = tipc_nl_parse_link_prop(attrs[TIPC_NLA_LINK_PROP],
1574                                               props);
1575                 if (err) {
1576                         res = err;
1577                         goto out;
1578                 }
1579
1580                 if (props[TIPC_NLA_PROP_TOL]) {
1581                         u32 tol;
1582
1583                         tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
1584                         link->tolerance = tol;
1585                         tipc_link_proto_xmit(link, STATE_MSG, 0, 0, tol, 0);
1586                 }
1587                 if (props[TIPC_NLA_PROP_PRIO]) {
1588                         u32 prio;
1589
1590                         prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
1591                         link->priority = prio;
1592                         tipc_link_proto_xmit(link, STATE_MSG, 0, 0, 0, prio);
1593                 }
1594                 if (props[TIPC_NLA_PROP_WIN]) {
1595                         u32 win;
1596
1597                         win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
1598                         tipc_link_set_queue_limits(link, win);
1599                 }
1600         }
1601
1602 out:
1603         tipc_node_unlock(node);
1604
1605         return res;
1606 }
1607
1608 static int __tipc_nl_add_stats(struct sk_buff *skb, struct tipc_stats *s)
1609 {
1610         int i;
1611         struct nlattr *stats;
1612
1613         struct nla_map {
1614                 u32 key;
1615                 u32 val;
1616         };
1617
1618         struct nla_map map[] = {
1619                 {TIPC_NLA_STATS_RX_INFO, s->recv_info},
1620                 {TIPC_NLA_STATS_RX_FRAGMENTS, s->recv_fragments},
1621                 {TIPC_NLA_STATS_RX_FRAGMENTED, s->recv_fragmented},
1622                 {TIPC_NLA_STATS_RX_BUNDLES, s->recv_bundles},
1623                 {TIPC_NLA_STATS_RX_BUNDLED, s->recv_bundled},
1624                 {TIPC_NLA_STATS_TX_INFO, s->sent_info},
1625                 {TIPC_NLA_STATS_TX_FRAGMENTS, s->sent_fragments},
1626                 {TIPC_NLA_STATS_TX_FRAGMENTED, s->sent_fragmented},
1627                 {TIPC_NLA_STATS_TX_BUNDLES, s->sent_bundles},
1628                 {TIPC_NLA_STATS_TX_BUNDLED, s->sent_bundled},
1629                 {TIPC_NLA_STATS_MSG_PROF_TOT, (s->msg_length_counts) ?
1630                         s->msg_length_counts : 1},
1631                 {TIPC_NLA_STATS_MSG_LEN_CNT, s->msg_length_counts},
1632                 {TIPC_NLA_STATS_MSG_LEN_TOT, s->msg_lengths_total},
1633                 {TIPC_NLA_STATS_MSG_LEN_P0, s->msg_length_profile[0]},
1634                 {TIPC_NLA_STATS_MSG_LEN_P1, s->msg_length_profile[1]},
1635                 {TIPC_NLA_STATS_MSG_LEN_P2, s->msg_length_profile[2]},
1636                 {TIPC_NLA_STATS_MSG_LEN_P3, s->msg_length_profile[3]},
1637                 {TIPC_NLA_STATS_MSG_LEN_P4, s->msg_length_profile[4]},
1638                 {TIPC_NLA_STATS_MSG_LEN_P5, s->msg_length_profile[5]},
1639                 {TIPC_NLA_STATS_MSG_LEN_P6, s->msg_length_profile[6]},
1640                 {TIPC_NLA_STATS_RX_STATES, s->recv_states},
1641                 {TIPC_NLA_STATS_RX_PROBES, s->recv_probes},
1642                 {TIPC_NLA_STATS_RX_NACKS, s->recv_nacks},
1643                 {TIPC_NLA_STATS_RX_DEFERRED, s->deferred_recv},
1644                 {TIPC_NLA_STATS_TX_STATES, s->sent_states},
1645                 {TIPC_NLA_STATS_TX_PROBES, s->sent_probes},
1646                 {TIPC_NLA_STATS_TX_NACKS, s->sent_nacks},
1647                 {TIPC_NLA_STATS_TX_ACKS, s->sent_acks},
1648                 {TIPC_NLA_STATS_RETRANSMITTED, s->retransmitted},
1649                 {TIPC_NLA_STATS_DUPLICATES, s->duplicates},
1650                 {TIPC_NLA_STATS_LINK_CONGS, s->link_congs},
1651                 {TIPC_NLA_STATS_MAX_QUEUE, s->max_queue_sz},
1652                 {TIPC_NLA_STATS_AVG_QUEUE, s->queue_sz_counts ?
1653                         (s->accu_queue_sz / s->queue_sz_counts) : 0}
1654         };
1655
1656         stats = nla_nest_start(skb, TIPC_NLA_LINK_STATS);
1657         if (!stats)
1658                 return -EMSGSIZE;
1659
1660         for (i = 0; i <  ARRAY_SIZE(map); i++)
1661                 if (nla_put_u32(skb, map[i].key, map[i].val))
1662                         goto msg_full;
1663
1664         nla_nest_end(skb, stats);
1665
1666         return 0;
1667 msg_full:
1668         nla_nest_cancel(skb, stats);
1669
1670         return -EMSGSIZE;
1671 }
1672
1673 /* Caller should hold appropriate locks to protect the link */
1674 static int __tipc_nl_add_link(struct net *net, struct tipc_nl_msg *msg,
1675                               struct tipc_link *link, int nlflags)
1676 {
1677         int err;
1678         void *hdr;
1679         struct nlattr *attrs;
1680         struct nlattr *prop;
1681         struct tipc_net *tn = net_generic(net, tipc_net_id);
1682
1683         hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
1684                           nlflags, TIPC_NL_LINK_GET);
1685         if (!hdr)
1686                 return -EMSGSIZE;
1687
1688         attrs = nla_nest_start(msg->skb, TIPC_NLA_LINK);
1689         if (!attrs)
1690                 goto msg_full;
1691
1692         if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, link->name))
1693                 goto attr_msg_full;
1694         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_DEST,
1695                         tipc_cluster_mask(tn->own_addr)))
1696                 goto attr_msg_full;
1697         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_MTU, link->mtu))
1698                 goto attr_msg_full;
1699         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, link->rcv_nxt))
1700                 goto attr_msg_full;
1701         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, link->snd_nxt))
1702                 goto attr_msg_full;
1703
1704         if (tipc_link_is_up(link))
1705                 if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
1706                         goto attr_msg_full;
1707         if (tipc_link_is_active(link))
1708                 if (nla_put_flag(msg->skb, TIPC_NLA_LINK_ACTIVE))
1709                         goto attr_msg_full;
1710
1711         prop = nla_nest_start(msg->skb, TIPC_NLA_LINK_PROP);
1712         if (!prop)
1713                 goto attr_msg_full;
1714         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
1715                 goto prop_msg_full;
1716         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_TOL, link->tolerance))
1717                 goto prop_msg_full;
1718         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN,
1719                         link->window))
1720                 goto prop_msg_full;
1721         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
1722                 goto prop_msg_full;
1723         nla_nest_end(msg->skb, prop);
1724
1725         err = __tipc_nl_add_stats(msg->skb, &link->stats);
1726         if (err)
1727                 goto attr_msg_full;
1728
1729         nla_nest_end(msg->skb, attrs);
1730         genlmsg_end(msg->skb, hdr);
1731
1732         return 0;
1733
1734 prop_msg_full:
1735         nla_nest_cancel(msg->skb, prop);
1736 attr_msg_full:
1737         nla_nest_cancel(msg->skb, attrs);
1738 msg_full:
1739         genlmsg_cancel(msg->skb, hdr);
1740
1741         return -EMSGSIZE;
1742 }
1743
1744 /* Caller should hold node lock  */
1745 static int __tipc_nl_add_node_links(struct net *net, struct tipc_nl_msg *msg,
1746                                     struct tipc_node *node, u32 *prev_link)
1747 {
1748         u32 i;
1749         int err;
1750
1751         for (i = *prev_link; i < MAX_BEARERS; i++) {
1752                 *prev_link = i;
1753
1754                 if (!node->links[i].link)
1755                         continue;
1756
1757                 err = __tipc_nl_add_link(net, msg,
1758                                          node->links[i].link, NLM_F_MULTI);
1759                 if (err)
1760                         return err;
1761         }
1762         *prev_link = 0;
1763
1764         return 0;
1765 }
1766
1767 int tipc_nl_link_dump(struct sk_buff *skb, struct netlink_callback *cb)
1768 {
1769         struct net *net = sock_net(skb->sk);
1770         struct tipc_net *tn = net_generic(net, tipc_net_id);
1771         struct tipc_node *node;
1772         struct tipc_nl_msg msg;
1773         u32 prev_node = cb->args[0];
1774         u32 prev_link = cb->args[1];
1775         int done = cb->args[2];
1776         int err;
1777
1778         if (done)
1779                 return 0;
1780
1781         msg.skb = skb;
1782         msg.portid = NETLINK_CB(cb->skb).portid;
1783         msg.seq = cb->nlh->nlmsg_seq;
1784
1785         rcu_read_lock();
1786         if (prev_node) {
1787                 node = tipc_node_find(net, prev_node);
1788                 if (!node) {
1789                         /* We never set seq or call nl_dump_check_consistent()
1790                          * this means that setting prev_seq here will cause the
1791                          * consistence check to fail in the netlink callback
1792                          * handler. Resulting in the last NLMSG_DONE message
1793                          * having the NLM_F_DUMP_INTR flag set.
1794                          */
1795                         cb->prev_seq = 1;
1796                         goto out;
1797                 }
1798                 tipc_node_put(node);
1799
1800                 list_for_each_entry_continue_rcu(node, &tn->node_list,
1801                                                  list) {
1802                         tipc_node_lock(node);
1803                         err = __tipc_nl_add_node_links(net, &msg, node,
1804                                                        &prev_link);
1805                         tipc_node_unlock(node);
1806                         if (err)
1807                                 goto out;
1808
1809                         prev_node = node->addr;
1810                 }
1811         } else {
1812                 err = tipc_nl_add_bc_link(net, &msg);
1813                 if (err)
1814                         goto out;
1815
1816                 list_for_each_entry_rcu(node, &tn->node_list, list) {
1817                         tipc_node_lock(node);
1818                         err = __tipc_nl_add_node_links(net, &msg, node,
1819                                                        &prev_link);
1820                         tipc_node_unlock(node);
1821                         if (err)
1822                                 goto out;
1823
1824                         prev_node = node->addr;
1825                 }
1826         }
1827         done = 1;
1828 out:
1829         rcu_read_unlock();
1830
1831         cb->args[0] = prev_node;
1832         cb->args[1] = prev_link;
1833         cb->args[2] = done;
1834
1835         return skb->len;
1836 }
1837
1838 int tipc_nl_link_get(struct sk_buff *skb, struct genl_info *info)
1839 {
1840         struct net *net = genl_info_net(info);
1841         struct tipc_nl_msg msg;
1842         char *name;
1843         int err;
1844
1845         msg.portid = info->snd_portid;
1846         msg.seq = info->snd_seq;
1847
1848         if (!info->attrs[TIPC_NLA_LINK_NAME])
1849                 return -EINVAL;
1850         name = nla_data(info->attrs[TIPC_NLA_LINK_NAME]);
1851
1852         msg.skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
1853         if (!msg.skb)
1854                 return -ENOMEM;
1855
1856         if (strcmp(name, tipc_bclink_name) == 0) {
1857                 err = tipc_nl_add_bc_link(net, &msg);
1858                 if (err) {
1859                         nlmsg_free(msg.skb);
1860                         return err;
1861                 }
1862         } else {
1863                 int bearer_id;
1864                 struct tipc_node *node;
1865                 struct tipc_link *link;
1866
1867                 node = tipc_link_find_owner(net, name, &bearer_id);
1868                 if (!node)
1869                         return -EINVAL;
1870
1871                 tipc_node_lock(node);
1872                 link = node->links[bearer_id].link;
1873                 if (!link) {
1874                         tipc_node_unlock(node);
1875                         nlmsg_free(msg.skb);
1876                         return -EINVAL;
1877                 }
1878
1879                 err = __tipc_nl_add_link(net, &msg, link, 0);
1880                 tipc_node_unlock(node);
1881                 if (err) {
1882                         nlmsg_free(msg.skb);
1883                         return err;
1884                 }
1885         }
1886
1887         return genlmsg_reply(msg.skb, info);
1888 }
1889
1890 int tipc_nl_link_reset_stats(struct sk_buff *skb, struct genl_info *info)
1891 {
1892         int err;
1893         char *link_name;
1894         unsigned int bearer_id;
1895         struct tipc_link *link;
1896         struct tipc_node *node;
1897         struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
1898         struct net *net = sock_net(skb->sk);
1899
1900         if (!info->attrs[TIPC_NLA_LINK])
1901                 return -EINVAL;
1902
1903         err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
1904                                info->attrs[TIPC_NLA_LINK],
1905                                tipc_nl_link_policy);
1906         if (err)
1907                 return err;
1908
1909         if (!attrs[TIPC_NLA_LINK_NAME])
1910                 return -EINVAL;
1911
1912         link_name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
1913
1914         if (strcmp(link_name, tipc_bclink_name) == 0) {
1915                 err = tipc_bclink_reset_stats(net);
1916                 if (err)
1917                         return err;
1918                 return 0;
1919         }
1920
1921         node = tipc_link_find_owner(net, link_name, &bearer_id);
1922         if (!node)
1923                 return -EINVAL;
1924
1925         tipc_node_lock(node);
1926
1927         link = node->links[bearer_id].link;
1928         if (!link) {
1929                 tipc_node_unlock(node);
1930                 return -EINVAL;
1931         }
1932
1933         link_reset_statistics(link);
1934
1935         tipc_node_unlock(node);
1936
1937         return 0;
1938 }