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_peer_is_down(struct tipc_link *l)
 124 {
 125         return l->state == LINK_PEER_RESET;
 126 }
 127
 128 bool tipc_link_is_reset(struct tipc_link *l)
 129 {
 130         return l->state & (LINK_RESET | LINK_FAILINGOVER | LINK_ESTABLISHING);
 131 }
 132
 133 bool tipc_link_is_establishing(struct tipc_link *l)
 134 {
 135         return l->state == LINK_ESTABLISHING;
 136 }
 137
 138 bool tipc_link_is_synching(struct tipc_link *l)
 139 {
 140         return l->state == LINK_SYNCHING;
 141 }
 142
 143 bool tipc_link_is_failingover(struct tipc_link *l)
 144 {
 145         return l->state == LINK_FAILINGOVER;
 146 }
 147
 148 bool tipc_link_is_blocked(struct tipc_link *l)
 149 {
 150         return l->state & (LINK_RESETTING | LINK_PEER_RESET | LINK_FAILINGOVER);
 151 }
 152
 153 int tipc_link_is_active(struct tipc_link *l)
 154 {
 155         struct tipc_node *n = l->owner;
 156
 157         return (node_active_link(n, 0) == l) || (node_active_link(n, 1) == l);
 158 }
 159
 160 static u32 link_own_addr(struct tipc_link *l)
 161 {
 162         return msg_prevnode(l->pmsg);
 163 }
 164
 165 /**
 166  * tipc_link_create - create a new link
 167  * @n: pointer to associated node
 168  * @b: pointer to associated bearer
 169  * @ownnode: identity of own node
 170  * @peer: identity of peer node
 171  * @maddr: media address to be used
 172  * @inputq: queue to put messages ready for delivery
 173  * @namedq: queue to put binding table update messages ready for delivery
 174  * @link: return value, pointer to put the created link
 175  *
 176  * Returns true if link was created, otherwise false
 177  */
 178 bool tipc_link_create(struct tipc_node *n, struct tipc_bearer *b, u32 session,
 179                       u32 ownnode, u32 peer, struct tipc_media_addr *maddr,
 180                       struct sk_buff_head *inputq, struct sk_buff_head *namedq,
 181                       struct tipc_link **link)
 182 {
 183         struct tipc_link *l;
 184         struct tipc_msg *hdr;
 185         char *if_name;
 186
 187         l = kzalloc(sizeof(*l), GFP_ATOMIC);
 188         if (!l)
 189                 return false;
 190         *link = l;
 191
 192         /* Note: peer i/f name is completed by reset/activate message */
 193         if_name = strchr(b->name, ':') + 1;
 194         sprintf(l->name, "%u.%u.%u:%s-%u.%u.%u:unknown",
 195                 tipc_zone(ownnode), tipc_cluster(ownnode), tipc_node(ownnode),
 196                 if_name, tipc_zone(peer), tipc_cluster(peer), tipc_node(peer));
 197
 198         l->addr = peer;
 199         l->media_addr = maddr;
 200         l->owner = n;
 201         l->peer_session = WILDCARD_SESSION;
 202         l->bearer_id = b->identity;
 203         l->tolerance = b->tolerance;
 204         l->net_plane = b->net_plane;
 205         l->advertised_mtu = b->mtu;
 206         l->mtu = b->mtu;
 207         l->priority = b->priority;
 208         tipc_link_set_queue_limits(l, b->window);
 209         l->inputq = inputq;
 210         l->namedq = namedq;
 211         l->state = LINK_RESETTING;
 212         l->pmsg = (struct tipc_msg *)&l->proto_msg;
 213         hdr = l->pmsg;
 214         tipc_msg_init(ownnode, hdr, LINK_PROTOCOL, RESET_MSG, INT_H_SIZE, peer);
 215         msg_set_size(hdr, sizeof(l->proto_msg));
 216         msg_set_session(hdr, session);
 217         msg_set_bearer_id(hdr, l->bearer_id);
 218         strcpy((char *)msg_data(hdr), if_name);
 219         __skb_queue_head_init(&l->transmq);
 220         __skb_queue_head_init(&l->backlogq);
 221         __skb_queue_head_init(&l->deferdq);
 222         skb_queue_head_init(&l->wakeupq);
 223         skb_queue_head_init(l->inputq);
 224         return true;
 225 }
 226
 227 /* tipc_link_build_bcast_sync_msg() - synchronize broadcast link endpoints.
 228  *
 229  * Give a newly added peer node the sequence number where it should
 230  * start receiving and acking broadcast packets.
 231  */
 232 void tipc_link_build_bcast_sync_msg(struct tipc_link *l,
 233                                     struct sk_buff_head *xmitq)
 234 {
 235         struct sk_buff *skb;
 236         struct sk_buff_head list;
 237         u16 last_sent;
 238
 239         skb = tipc_msg_create(BCAST_PROTOCOL, STATE_MSG, INT_H_SIZE,
 240                               0, l->addr, link_own_addr(l), 0, 0, 0);
 241         if (!skb)
 242                 return;
 243         last_sent = tipc_bclink_get_last_sent(l->owner->net);
 244         msg_set_last_bcast(buf_msg(skb), last_sent);
 245         __skb_queue_head_init(&list);
 246         __skb_queue_tail(&list, skb);
 247         tipc_link_xmit(l, &list, xmitq);
 248 }
 249
 250 /**
 251  * tipc_link_fsm_evt - link finite state machine
 252  * @l: pointer to link
 253  * @evt: state machine event to be processed
 254  */
 255 int tipc_link_fsm_evt(struct tipc_link *l, int evt)
 256 {
 257         int rc = 0;
 258
 259         switch (l->state) {
 260         case LINK_RESETTING:
 261                 switch (evt) {
 262                 case LINK_PEER_RESET_EVT:
 263                         l->state = LINK_PEER_RESET;
 264                         break;
 265                 case LINK_RESET_EVT:
 266                         l->state = LINK_RESET;
 267                         break;
 268                 case LINK_FAILURE_EVT:
 269                 case LINK_FAILOVER_BEGIN_EVT:
 270                 case LINK_ESTABLISH_EVT:
 271                 case LINK_FAILOVER_END_EVT:
 272                 case LINK_SYNCH_BEGIN_EVT:
 273                 case LINK_SYNCH_END_EVT:
 274                 default:
 275                         goto illegal_evt;
 276                 }
 277                 break;
 278         case LINK_RESET:
 279                 switch (evt) {
 280                 case LINK_PEER_RESET_EVT:
 281                         l->state = LINK_ESTABLISHING;
 282                         break;
 283                 case LINK_FAILOVER_BEGIN_EVT:
 284                         l->state = LINK_FAILINGOVER;
 285                 case LINK_FAILURE_EVT:
 286                 case LINK_RESET_EVT:
 287                 case LINK_ESTABLISH_EVT:
 288                 case LINK_FAILOVER_END_EVT:
 289                         break;
 290                 case LINK_SYNCH_BEGIN_EVT:
 291                 case LINK_SYNCH_END_EVT:
 292                 default:
 293                         goto illegal_evt;
 294                 }
 295                 break;
 296         case LINK_PEER_RESET:
 297                 switch (evt) {
 298                 case LINK_RESET_EVT:
 299                         l->state = LINK_ESTABLISHING;
 300                         break;
 301                 case LINK_PEER_RESET_EVT:
 302                 case LINK_ESTABLISH_EVT:
 303                 case LINK_FAILURE_EVT:
 304                         break;
 305                 case LINK_SYNCH_BEGIN_EVT:
 306                 case LINK_SYNCH_END_EVT:
 307                 case LINK_FAILOVER_BEGIN_EVT:
 308                 case LINK_FAILOVER_END_EVT:
 309                 default:
 310                         goto illegal_evt;
 311                 }
 312                 break;
 313         case LINK_FAILINGOVER:
 314                 switch (evt) {
 315                 case LINK_FAILOVER_END_EVT:
 316                         l->state = LINK_RESET;
 317                         break;
 318                 case LINK_PEER_RESET_EVT:
 319                 case LINK_RESET_EVT:
 320                 case LINK_ESTABLISH_EVT:
 321                 case LINK_FAILURE_EVT:
 322                         break;
 323                 case LINK_FAILOVER_BEGIN_EVT:
 324                 case LINK_SYNCH_BEGIN_EVT:
 325                 case LINK_SYNCH_END_EVT:
 326                 default:
 327                         goto illegal_evt;
 328                 }
 329                 break;
 330         case LINK_ESTABLISHING:
 331                 switch (evt) {
 332                 case LINK_ESTABLISH_EVT:
 333                         l->state = LINK_ESTABLISHED;
 334                         break;
 335                 case LINK_FAILOVER_BEGIN_EVT:
 336                         l->state = LINK_FAILINGOVER;
 337                         break;
 338                 case LINK_RESET_EVT:
 339                         l->state = LINK_RESET;
 340                         break;
 341                 case LINK_FAILURE_EVT:
 342                 case LINK_PEER_RESET_EVT:
 343                 case LINK_SYNCH_BEGIN_EVT:
 344                 case LINK_FAILOVER_END_EVT:
 345                         break;
 346                 case LINK_SYNCH_END_EVT:
 347                 default:
 348                         goto illegal_evt;
 349                 }
 350                 break;
 351         case LINK_ESTABLISHED:
 352                 switch (evt) {
 353                 case LINK_PEER_RESET_EVT:
 354                         l->state = LINK_PEER_RESET;
 355                         rc |= TIPC_LINK_DOWN_EVT;
 356                         break;
 357                 case LINK_FAILURE_EVT:
 358                         l->state = LINK_RESETTING;
 359                         rc |= TIPC_LINK_DOWN_EVT;
 360                         break;
 361                 case LINK_RESET_EVT:
 362                         l->state = LINK_RESET;
 363                         break;
 364                 case LINK_ESTABLISH_EVT:
 365                 case LINK_SYNCH_END_EVT:
 366                         break;
 367                 case LINK_SYNCH_BEGIN_EVT:
 368                         l->state = LINK_SYNCHING;
 369                         break;
 370                 case LINK_FAILOVER_BEGIN_EVT:
 371                 case LINK_FAILOVER_END_EVT:
 372                 default:
 373                         goto illegal_evt;
 374                 }
 375                 break;
 376         case LINK_SYNCHING:
 377                 switch (evt) {
 378                 case LINK_PEER_RESET_EVT:
 379                         l->state = LINK_PEER_RESET;
 380                         rc |= TIPC_LINK_DOWN_EVT;
 381                         break;
 382                 case LINK_FAILURE_EVT:
 383                         l->state = LINK_RESETTING;
 384                         rc |= TIPC_LINK_DOWN_EVT;
 385                         break;
 386                 case LINK_RESET_EVT:
 387                         l->state = LINK_RESET;
 388                         break;
 389                 case LINK_ESTABLISH_EVT:
 390                 case LINK_SYNCH_BEGIN_EVT:
 391                         break;
 392                 case LINK_SYNCH_END_EVT:
 393                         l->state = LINK_ESTABLISHED;
 394                         break;
 395                 case LINK_FAILOVER_BEGIN_EVT:
 396                 case LINK_FAILOVER_END_EVT:
 397                 default:
 398                         goto illegal_evt;
 399                 }
 400                 break;
 401         default:
 402                 pr_err("Unknown FSM state %x in %s\n", l->state, l->name);
 403         }
 404         return rc;
 405 illegal_evt:
 406         pr_err("Illegal FSM event %x in state %x on link %s\n",
 407                evt, l->state, l->name);
 408         return rc;
 409 }
 410
 411 /* link_profile_stats - update statistical profiling of traffic
 412  */
 413 static void link_profile_stats(struct tipc_link *l)
 414 {
 415         struct sk_buff *skb;
 416         struct tipc_msg *msg;
 417         int length;
 418
 419         /* Update counters used in statistical profiling of send traffic */
 420         l->stats.accu_queue_sz += skb_queue_len(&l->transmq);
 421         l->stats.queue_sz_counts++;
 422
 423         skb = skb_peek(&l->transmq);
 424         if (!skb)
 425                 return;
 426         msg = buf_msg(skb);
 427         length = msg_size(msg);
 428
 429         if (msg_user(msg) == MSG_FRAGMENTER) {
 430                 if (msg_type(msg) != FIRST_FRAGMENT)
 431                         return;
 432                 length = msg_size(msg_get_wrapped(msg));
 433         }
 434         l->stats.msg_lengths_total += length;
 435         l->stats.msg_length_counts++;
 436         if (length <= 64)
 437                 l->stats.msg_length_profile[0]++;
 438         else if (length <= 256)
 439                 l->stats.msg_length_profile[1]++;
 440         else if (length <= 1024)
 441                 l->stats.msg_length_profile[2]++;
 442         else if (length <= 4096)
 443                 l->stats.msg_length_profile[3]++;
 444         else if (length <= 16384)
 445                 l->stats.msg_length_profile[4]++;
 446         else if (length <= 32768)
 447                 l->stats.msg_length_profile[5]++;
 448         else
 449                 l->stats.msg_length_profile[6]++;
 450 }
 451
 452 /* tipc_link_timeout - perform periodic task as instructed from node timeout
 453  */
 454 int tipc_link_timeout(struct tipc_link *l, struct sk_buff_head *xmitq)
 455 {
 456         int rc = 0;
 457         int mtyp = STATE_MSG;
 458         bool xmit = false;
 459         bool prb = false;
 460
 461         link_profile_stats(l);
 462
 463         switch (l->state) {
 464         case LINK_ESTABLISHED:
 465         case LINK_SYNCHING:
 466                 if (!l->silent_intv_cnt) {
 467                         if (tipc_bclink_acks_missing(l->owner))
 468                                 xmit = true;
 469                 } else if (l->silent_intv_cnt <= l->abort_limit) {
 470                         xmit = true;
 471                         prb = true;
 472                 } else {
 473                         rc |= tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
 474                 }
 475                 l->silent_intv_cnt++;
 476                 break;
 477         case LINK_RESET:
 478                 xmit = true;
 479                 mtyp = RESET_MSG;
 480                 break;
 481         case LINK_ESTABLISHING:
 482                 xmit = true;
 483                 mtyp = ACTIVATE_MSG;
 484                 break;
 485         case LINK_PEER_RESET:
 486         case LINK_RESETTING:
 487         case LINK_FAILINGOVER:
 488                 break;
 489         default:
 490                 break;
 491         }
 492
 493         if (xmit)
 494                 tipc_link_build_proto_msg(l, mtyp, prb, 0, 0, 0, xmitq);
 495
 496         return rc;
 497 }
 498
 499 /**
 500  * link_schedule_user - schedule a message sender for wakeup after congestion
 501  * @link: congested link
 502  * @list: message that was attempted sent
 503  * Create pseudo msg to send back to user when congestion abates
 504  * Does not consume buffer list
 505  */
 506 static int link_schedule_user(struct tipc_link *link, struct sk_buff_head *list)
 507 {
 508         struct tipc_msg *msg = buf_msg(skb_peek(list));
 509         int imp = msg_importance(msg);
 510         u32 oport = msg_origport(msg);
 511         u32 addr = link_own_addr(link);
 512         struct sk_buff *skb;
 513
 514         /* This really cannot happen...  */
 515         if (unlikely(imp > TIPC_CRITICAL_IMPORTANCE)) {
 516                 pr_warn("%s<%s>, send queue full", link_rst_msg, link->name);
 517                 return -ENOBUFS;
 518         }
 519         /* Non-blocking sender: */
 520         if (TIPC_SKB_CB(skb_peek(list))->wakeup_pending)
 521                 return -ELINKCONG;
 522
 523         /* Create and schedule wakeup pseudo message */
 524         skb = tipc_msg_create(SOCK_WAKEUP, 0, INT_H_SIZE, 0,
 525                               addr, addr, oport, 0, 0);
 526         if (!skb)
 527                 return -ENOBUFS;
 528         TIPC_SKB_CB(skb)->chain_sz = skb_queue_len(list);
 529         TIPC_SKB_CB(skb)->chain_imp = imp;
 530         skb_queue_tail(&link->wakeupq, skb);
 531         link->stats.link_congs++;
 532         return -ELINKCONG;
 533 }
 534
 535 /**
 536  * link_prepare_wakeup - prepare users for wakeup after congestion
 537  * @link: congested link
 538  * Move a number of waiting users, as permitted by available space in
 539  * the send queue, from link wait queue to node wait queue for wakeup
 540  */
 541 void link_prepare_wakeup(struct tipc_link *l)
 542 {
 543         int pnd[TIPC_SYSTEM_IMPORTANCE + 1] = {0,};
 544         int imp, lim;
 545         struct sk_buff *skb, *tmp;
 546
 547         skb_queue_walk_safe(&l->wakeupq, skb, tmp) {
 548                 imp = TIPC_SKB_CB(skb)->chain_imp;
 549                 lim = l->window + l->backlog[imp].limit;
 550                 pnd[imp] += TIPC_SKB_CB(skb)->chain_sz;
 551                 if ((pnd[imp] + l->backlog[imp].len) >= lim)
 552                         break;
 553                 skb_unlink(skb, &l->wakeupq);
 554                 skb_queue_tail(l->inputq, skb);
 555         }
 556 }
 557
 558 /**
 559  * tipc_link_reset_fragments - purge link's inbound message fragments queue
 560  * @l_ptr: pointer to link
 561  */
 562 void tipc_link_reset_fragments(struct tipc_link *l_ptr)
 563 {
 564         kfree_skb(l_ptr->reasm_buf);
 565         l_ptr->reasm_buf = NULL;
 566 }
 567
 568 void tipc_link_purge_backlog(struct tipc_link *l)
 569 {
 570         __skb_queue_purge(&l->backlogq);
 571         l->backlog[TIPC_LOW_IMPORTANCE].len = 0;
 572         l->backlog[TIPC_MEDIUM_IMPORTANCE].len = 0;
 573         l->backlog[TIPC_HIGH_IMPORTANCE].len = 0;
 574         l->backlog[TIPC_CRITICAL_IMPORTANCE].len = 0;
 575         l->backlog[TIPC_SYSTEM_IMPORTANCE].len = 0;
 576 }
 577
 578 /**
 579  * tipc_link_purge_queues - purge all pkt queues associated with link
 580  * @l_ptr: pointer to link
 581  */
 582 void tipc_link_purge_queues(struct tipc_link *l_ptr)
 583 {
 584         __skb_queue_purge(&l_ptr->deferdq);
 585         __skb_queue_purge(&l_ptr->transmq);
 586         tipc_link_purge_backlog(l_ptr);
 587         tipc_link_reset_fragments(l_ptr);
 588 }
 589
 590 void tipc_link_reset(struct tipc_link *l)
 591 {
 592         /* Link is down, accept any session */
 593         l->peer_session = WILDCARD_SESSION;
 594
 595         /* If peer is up, it only accepts an incremented session number */
 596         msg_set_session(l->pmsg, msg_session(l->pmsg) + 1);
 597
 598         /* Prepare for renewed mtu size negotiation */
 599         l->mtu = l->advertised_mtu;
 600
 601         /* Clean up all queues: */
 602         __skb_queue_purge(&l->transmq);
 603         __skb_queue_purge(&l->deferdq);
 604         skb_queue_splice_init(&l->wakeupq, l->inputq);
 605
 606         tipc_link_purge_backlog(l);
 607         kfree_skb(l->reasm_buf);
 608         kfree_skb(l->failover_reasm_skb);
 609         l->reasm_buf = NULL;
 610         l->failover_reasm_skb = NULL;
 611         l->rcv_unacked = 0;
 612         l->snd_nxt = 1;
 613         l->rcv_nxt = 1;
 614         l->silent_intv_cnt = 0;
 615         l->stats.recv_info = 0;
 616         l->stale_count = 0;
 617         link_reset_statistics(l);
 618 }
 619
 620 /**
 621  * __tipc_link_xmit(): same as tipc_link_xmit, but destlink is known & locked
 622  * @link: link to use
 623  * @list: chain of buffers containing message
 624  *
 625  * Consumes the buffer chain, except when returning an error code,
 626  * Returns 0 if success, or errno: -ELINKCONG, -EMSGSIZE or -ENOBUFS
 627  * Messages at TIPC_SYSTEM_IMPORTANCE are always accepted
 628  */
 629 int __tipc_link_xmit(struct net *net, struct tipc_link *link,
 630                      struct sk_buff_head *list)
 631 {
 632         struct tipc_msg *msg = buf_msg(skb_peek(list));
 633         unsigned int maxwin = link->window;
 634         unsigned int i, imp = msg_importance(msg);
 635         uint mtu = link->mtu;
 636         u16 ack = mod(link->rcv_nxt - 1);
 637         u16 seqno = link->snd_nxt;
 638         u16 bc_last_in = link->owner->bclink.last_in;
 639         struct tipc_media_addr *addr = link->media_addr;
 640         struct sk_buff_head *transmq = &link->transmq;
 641         struct sk_buff_head *backlogq = &link->backlogq;
 642         struct sk_buff *skb, *bskb;
 643
 644         /* Match msg importance against this and all higher backlog limits: */
 645         for (i = imp; i <= TIPC_SYSTEM_IMPORTANCE; i++) {
 646                 if (unlikely(link->backlog[i].len >= link->backlog[i].limit))
 647                         return link_schedule_user(link, list);
 648         }
 649         if (unlikely(msg_size(msg) > mtu))
 650                 return -EMSGSIZE;
 651
 652         /* Prepare each packet for sending, and add to relevant queue: */
 653         while (skb_queue_len(list)) {
 654                 skb = skb_peek(list);
 655                 msg = buf_msg(skb);
 656                 msg_set_seqno(msg, seqno);
 657                 msg_set_ack(msg, ack);
 658                 msg_set_bcast_ack(msg, bc_last_in);
 659
 660                 if (likely(skb_queue_len(transmq) < maxwin)) {
 661                         __skb_dequeue(list);
 662                         __skb_queue_tail(transmq, skb);
 663                         tipc_bearer_send(net, link->bearer_id, skb, addr);
 664                         link->rcv_unacked = 0;
 665                         seqno++;
 666                         continue;
 667                 }
 668                 if (tipc_msg_bundle(skb_peek_tail(backlogq), msg, mtu)) {
 669                         kfree_skb(__skb_dequeue(list));
 670                         link->stats.sent_bundled++;
 671                         continue;
 672                 }
 673                 if (tipc_msg_make_bundle(&bskb, msg, mtu, link->addr)) {
 674                         kfree_skb(__skb_dequeue(list));
 675                         __skb_queue_tail(backlogq, bskb);
 676                         link->backlog[msg_importance(buf_msg(bskb))].len++;
 677                         link->stats.sent_bundled++;
 678                         link->stats.sent_bundles++;
 679                         continue;
 680                 }
 681                 link->backlog[imp].len += skb_queue_len(list);
 682                 skb_queue_splice_tail_init(list, backlogq);
 683         }
 684         link->snd_nxt = seqno;
 685         return 0;
 686 }
 687
 688 /**
 689  * tipc_link_xmit(): enqueue buffer list according to queue situation
 690  * @link: link to use
 691  * @list: chain of buffers containing message
 692  * @xmitq: returned list of packets to be sent by caller
 693  *
 694  * Consumes the buffer chain, except when returning -ELINKCONG,
 695  * since the caller then may want to make more send attempts.
 696  * Returns 0 if success, or errno: -ELINKCONG, -EMSGSIZE or -ENOBUFS
 697  * Messages at TIPC_SYSTEM_IMPORTANCE are always accepted
 698  */
 699 int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *list,
 700                    struct sk_buff_head *xmitq)
 701 {
 702         struct tipc_msg *hdr = buf_msg(skb_peek(list));
 703         unsigned int maxwin = l->window;
 704         unsigned int i, imp = msg_importance(hdr);
 705         unsigned int mtu = l->mtu;
 706         u16 ack = l->rcv_nxt - 1;
 707         u16 seqno = l->snd_nxt;
 708         u16 bc_last_in = l->owner->bclink.last_in;
 709         struct sk_buff_head *transmq = &l->transmq;
 710         struct sk_buff_head *backlogq = &l->backlogq;
 711         struct sk_buff *skb, *_skb, *bskb;
 712
 713         /* Match msg importance against this and all higher backlog limits: */
 714         for (i = imp; i <= TIPC_SYSTEM_IMPORTANCE; i++) {
 715                 if (unlikely(l->backlog[i].len >= l->backlog[i].limit))
 716                         return link_schedule_user(l, list);
 717         }
 718         if (unlikely(msg_size(hdr) > mtu))
 719                 return -EMSGSIZE;
 720
 721         /* Prepare each packet for sending, and add to relevant queue: */
 722         while (skb_queue_len(list)) {
 723                 skb = skb_peek(list);
 724                 hdr = buf_msg(skb);
 725                 msg_set_seqno(hdr, seqno);
 726                 msg_set_ack(hdr, ack);
 727                 msg_set_bcast_ack(hdr, bc_last_in);
 728
 729                 if (likely(skb_queue_len(transmq) < maxwin)) {
 730                         _skb = skb_clone(skb, GFP_ATOMIC);
 731                         if (!_skb)
 732                                 return -ENOBUFS;
 733                         __skb_dequeue(list);
 734                         __skb_queue_tail(transmq, skb);
 735                         __skb_queue_tail(xmitq, _skb);
 736                         l->rcv_unacked = 0;
 737                         seqno++;
 738                         continue;
 739                 }
 740                 if (tipc_msg_bundle(skb_peek_tail(backlogq), hdr, mtu)) {
 741                         kfree_skb(__skb_dequeue(list));
 742                         l->stats.sent_bundled++;
 743                         continue;
 744                 }
 745                 if (tipc_msg_make_bundle(&bskb, hdr, mtu, l->addr)) {
 746                         kfree_skb(__skb_dequeue(list));
 747                         __skb_queue_tail(backlogq, bskb);
 748                         l->backlog[msg_importance(buf_msg(bskb))].len++;
 749                         l->stats.sent_bundled++;
 750                         l->stats.sent_bundles++;
 751                         continue;
 752                 }
 753                 l->backlog[imp].len += skb_queue_len(list);
 754                 skb_queue_splice_tail_init(list, backlogq);
 755         }
 756         l->snd_nxt = seqno;
 757         return 0;
 758 }
 759
 760 /*
 761  * tipc_link_sync_rcv - synchronize broadcast link endpoints.
 762  * Receive the sequence number where we should start receiving and
 763  * acking broadcast packets from a newly added peer node, and open
 764  * up for reception of such packets.
 765  *
 766  * Called with node locked
 767  */
 768 static void tipc_link_sync_rcv(struct tipc_node *n, struct sk_buff *buf)
 769 {
 770         struct tipc_msg *msg = buf_msg(buf);
 771
 772         n->bclink.last_sent = n->bclink.last_in = msg_last_bcast(msg);
 773         n->bclink.recv_permitted = true;
 774         kfree_skb(buf);
 775 }
 776
 777 /*
 778  * tipc_link_push_packets - push unsent packets to bearer
 779  *
 780  * Push out the unsent messages of a link where congestion
 781  * has abated. Node is locked.
 782  *
 783  * Called with node locked
 784  */
 785 void tipc_link_push_packets(struct tipc_link *link)
 786 {
 787         struct sk_buff *skb;
 788         struct tipc_msg *msg;
 789         u16 seqno = link->snd_nxt;
 790         u16 ack = mod(link->rcv_nxt - 1);
 791
 792         while (skb_queue_len(&link->transmq) < link->window) {
 793                 skb = __skb_dequeue(&link->backlogq);
 794                 if (!skb)
 795                         break;
 796                 msg = buf_msg(skb);
 797                 link->backlog[msg_importance(msg)].len--;
 798                 msg_set_ack(msg, ack);
 799                 msg_set_seqno(msg, seqno);
 800                 seqno = mod(seqno + 1);
 801                 msg_set_bcast_ack(msg, link->owner->bclink.last_in);
 802                 link->rcv_unacked = 0;
 803                 __skb_queue_tail(&link->transmq, skb);
 804                 tipc_bearer_send(link->owner->net, link->bearer_id,
 805                                  skb, link->media_addr);
 806         }
 807         link->snd_nxt = seqno;
 808 }
 809
 810 void tipc_link_advance_backlog(struct tipc_link *l, struct sk_buff_head *xmitq)
 811 {
 812         struct sk_buff *skb, *_skb;
 813         struct tipc_msg *hdr;
 814         u16 seqno = l->snd_nxt;
 815         u16 ack = l->rcv_nxt - 1;
 816
 817         while (skb_queue_len(&l->transmq) < l->window) {
 818                 skb = skb_peek(&l->backlogq);
 819                 if (!skb)
 820                         break;
 821                 _skb = skb_clone(skb, GFP_ATOMIC);
 822                 if (!_skb)
 823                         break;
 824                 __skb_dequeue(&l->backlogq);
 825                 hdr = buf_msg(skb);
 826                 l->backlog[msg_importance(hdr)].len--;
 827                 __skb_queue_tail(&l->transmq, skb);
 828                 __skb_queue_tail(xmitq, _skb);
 829                 msg_set_ack(hdr, ack);
 830                 msg_set_seqno(hdr, seqno);
 831                 msg_set_bcast_ack(hdr, l->owner->bclink.last_in);
 832                 l->rcv_unacked = 0;
 833                 seqno++;
 834         }
 835         l->snd_nxt = seqno;
 836 }
 837
 838 static void link_retransmit_failure(struct tipc_link *l_ptr,
 839                                     struct sk_buff *buf)
 840 {
 841         struct tipc_msg *msg = buf_msg(buf);
 842         struct net *net = l_ptr->owner->net;
 843
 844         pr_warn("Retransmission failure on link <%s>\n", l_ptr->name);
 845
 846         if (l_ptr->addr) {
 847                 /* Handle failure on standard link */
 848                 link_print(l_ptr, "Resetting link ");
 849                 pr_info("Failed msg: usr %u, typ %u, len %u, err %u\n",
 850                         msg_user(msg), msg_type(msg), msg_size(msg),
 851                         msg_errcode(msg));
 852                 pr_info("sqno %u, prev: %x, src: %x\n",
 853                         msg_seqno(msg), msg_prevnode(msg), msg_orignode(msg));
 854         } else {
 855                 /* Handle failure on broadcast link */
 856                 struct tipc_node *n_ptr;
 857                 char addr_string[16];
 858
 859                 pr_info("Msg seq number: %u,  ", msg_seqno(msg));
 860                 pr_cont("Outstanding acks: %lu\n",
 861                         (unsigned long) TIPC_SKB_CB(buf)->handle);
 862
 863                 n_ptr = tipc_bclink_retransmit_to(net);
 864
 865                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 866                 pr_info("Broadcast link info for %s\n", addr_string);
 867                 pr_info("Reception permitted: %d,  Acked: %u\n",
 868                         n_ptr->bclink.recv_permitted,
 869                         n_ptr->bclink.acked);
 870                 pr_info("Last in: %u,  Oos state: %u,  Last sent: %u\n",
 871                         n_ptr->bclink.last_in,
 872                         n_ptr->bclink.oos_state,
 873                         n_ptr->bclink.last_sent);
 874
 875                 n_ptr->action_flags |= TIPC_BCAST_RESET;
 876                 l_ptr->stale_count = 0;
 877         }
 878 }
 879
 880 void tipc_link_retransmit(struct tipc_link *l_ptr, struct sk_buff *skb,
 881                           u32 retransmits)
 882 {
 883         struct tipc_msg *msg;
 884
 885         if (!skb)
 886                 return;
 887
 888         msg = buf_msg(skb);
 889
 890         /* Detect repeated retransmit failures */
 891         if (l_ptr->last_retransm == msg_seqno(msg)) {
 892                 if (++l_ptr->stale_count > 100) {
 893                         link_retransmit_failure(l_ptr, skb);
 894                         return;
 895                 }
 896         } else {
 897                 l_ptr->last_retransm = msg_seqno(msg);
 898                 l_ptr->stale_count = 1;
 899         }
 900
 901         skb_queue_walk_from(&l_ptr->transmq, skb) {
 902                 if (!retransmits)
 903                         break;
 904                 msg = buf_msg(skb);
 905                 msg_set_ack(msg, mod(l_ptr->rcv_nxt - 1));
 906                 msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
 907                 tipc_bearer_send(l_ptr->owner->net, l_ptr->bearer_id, skb,
 908                                  l_ptr->media_addr);
 909                 retransmits--;
 910                 l_ptr->stats.retransmitted++;
 911         }
 912 }
 913
 914 static int tipc_link_retransm(struct tipc_link *l, int retransm,
 915                               struct sk_buff_head *xmitq)
 916 {
 917         struct sk_buff *_skb, *skb = skb_peek(&l->transmq);
 918         struct tipc_msg *hdr;
 919
 920         if (!skb)
 921                 return 0;
 922
 923         /* Detect repeated retransmit failures on same packet */
 924         if (likely(l->last_retransm != buf_seqno(skb))) {
 925                 l->last_retransm = buf_seqno(skb);
 926                 l->stale_count = 1;
 927         } else if (++l->stale_count > 100) {
 928                 link_retransmit_failure(l, skb);
 929                 return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
 930         }
 931         skb_queue_walk(&l->transmq, skb) {
 932                 if (!retransm)
 933                         return 0;
 934                 hdr = buf_msg(skb);
 935                 _skb = __pskb_copy(skb, MIN_H_SIZE, GFP_ATOMIC);
 936                 if (!_skb)
 937                         return 0;
 938                 hdr = buf_msg(_skb);
 939                 msg_set_ack(hdr, l->rcv_nxt - 1);
 940                 msg_set_bcast_ack(hdr, l->owner->bclink.last_in);
 941                 _skb->priority = TC_PRIO_CONTROL;
 942                 __skb_queue_tail(xmitq, _skb);
 943                 retransm--;
 944                 l->stats.retransmitted++;
 945         }
 946         return 0;
 947 }
 948
 949 /* tipc_data_input - deliver data and name distr msgs to upper layer
 950  *
 951  * Consumes buffer if message is of right type
 952  * Node lock must be held
 953  */
 954 static bool tipc_data_input(struct tipc_link *link, struct sk_buff *skb,
 955                             struct sk_buff_head *inputq)
 956 {
 957         struct tipc_node *node = link->owner;
 958
 959         switch (msg_user(buf_msg(skb))) {
 960         case TIPC_LOW_IMPORTANCE:
 961         case TIPC_MEDIUM_IMPORTANCE:
 962         case TIPC_HIGH_IMPORTANCE:
 963         case TIPC_CRITICAL_IMPORTANCE:
 964         case CONN_MANAGER:
 965                 skb_queue_tail(inputq, skb);
 966                 return true;
 967         case NAME_DISTRIBUTOR:
 968                 node->bclink.recv_permitted = true;
 969                 skb_queue_tail(link->namedq, skb);
 970                 return true;
 971         case MSG_BUNDLER:
 972         case TUNNEL_PROTOCOL:
 973         case MSG_FRAGMENTER:
 974         case BCAST_PROTOCOL:
 975                 return false;
 976         default:
 977                 pr_warn("Dropping received illegal msg type\n");
 978                 kfree_skb(skb);
 979                 return false;
 980         };
 981 }
 982
 983 /* tipc_link_input - process packet that has passed link protocol check
 984  *
 985  * Consumes buffer
 986  */
 987 static int tipc_link_input(struct tipc_link *l, struct sk_buff *skb,
 988                            struct sk_buff_head *inputq)
 989 {
 990         struct tipc_node *node = l->owner;
 991         struct tipc_msg *hdr = buf_msg(skb);
 992         struct sk_buff **reasm_skb = &l->reasm_buf;
 993         struct sk_buff *iskb;
 994         struct sk_buff_head tmpq;
 995         int usr = msg_user(hdr);
 996         int rc = 0;
 997         int pos = 0;
 998         int ipos = 0;
 999
1000         if (unlikely(usr == TUNNEL_PROTOCOL)) {
1001                 if (msg_type(hdr) == SYNCH_MSG) {
1002                         __skb_queue_purge(&l->deferdq);
1003                         goto drop;
1004                 }
1005                 if (!tipc_msg_extract(skb, &iskb, &ipos))
1006                         return rc;
1007                 kfree_skb(skb);
1008                 skb = iskb;
1009                 hdr = buf_msg(skb);
1010                 if (less(msg_seqno(hdr), l->drop_point))
1011                         goto drop;
1012                 if (tipc_data_input(l, skb, inputq))
1013                         return rc;
1014                 usr = msg_user(hdr);
1015                 reasm_skb = &l->failover_reasm_skb;
1016         }
1017
1018         if (usr == MSG_BUNDLER) {
1019                 skb_queue_head_init(&tmpq);
1020                 l->stats.recv_bundles++;
1021                 l->stats.recv_bundled += msg_msgcnt(hdr);
1022                 while (tipc_msg_extract(skb, &iskb, &pos))
1023                         tipc_data_input(l, iskb, &tmpq);
1024                 tipc_skb_queue_splice_tail(&tmpq, inputq);
1025                 return 0;
1026         } else if (usr == MSG_FRAGMENTER) {
1027                 l->stats.recv_fragments++;
1028                 if (tipc_buf_append(reasm_skb, &skb)) {
1029                         l->stats.recv_fragmented++;
1030                         tipc_data_input(l, skb, inputq);
1031                 } else if (!*reasm_skb) {
1032                         return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1033                 }
1034                 return 0;
1035         } else if (usr == BCAST_PROTOCOL) {
1036                 tipc_link_sync_rcv(node, skb);
1037                 return 0;
1038         }
1039 drop:
1040         kfree_skb(skb);
1041         return 0;
1042 }
1043
1044 static bool tipc_link_release_pkts(struct tipc_link *l, u16 acked)
1045 {
1046         bool released = false;
1047         struct sk_buff *skb, *tmp;
1048
1049         skb_queue_walk_safe(&l->transmq, skb, tmp) {
1050                 if (more(buf_seqno(skb), acked))
1051                         break;
1052                 __skb_unlink(skb, &l->transmq);
1053                 kfree_skb(skb);
1054                 released = true;
1055         }
1056         return released;
1057 }
1058
1059 /* tipc_link_build_ack_msg: prepare link acknowledge message for transmission
1060  */
1061 void tipc_link_build_ack_msg(struct tipc_link *l, struct sk_buff_head *xmitq)
1062 {
1063         l->rcv_unacked = 0;
1064         l->stats.sent_acks++;
1065         tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, 0, xmitq);
1066 }
1067
1068 /* tipc_link_build_reset_msg: prepare link RESET or ACTIVATE message
1069  */
1070 void tipc_link_build_reset_msg(struct tipc_link *l, struct sk_buff_head *xmitq)
1071 {
1072         int mtyp = RESET_MSG;
1073
1074         if (l->state == LINK_ESTABLISHING)
1075                 mtyp = ACTIVATE_MSG;
1076
1077         tipc_link_build_proto_msg(l, mtyp, 0, 0, 0, 0, xmitq);
1078 }
1079
1080 /* tipc_link_build_nack_msg: prepare link nack message for transmission
1081  */
1082 static void tipc_link_build_nack_msg(struct tipc_link *l,
1083                                      struct sk_buff_head *xmitq)
1084 {
1085         u32 def_cnt = ++l->stats.deferred_recv;
1086
1087         if ((skb_queue_len(&l->deferdq) == 1) || !(def_cnt % TIPC_NACK_INTV))
1088                 tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, 0, xmitq);
1089 }
1090
1091 /* tipc_link_rcv - process TIPC packets/messages arriving from off-node
1092  * @l: the link that should handle the message
1093  * @skb: TIPC packet
1094  * @xmitq: queue to place packets to be sent after this call
1095  */
1096 int tipc_link_rcv(struct tipc_link *l, struct sk_buff *skb,
1097                   struct sk_buff_head *xmitq)
1098 {
1099         struct sk_buff_head *defq = &l->deferdq;
1100         struct tipc_msg *hdr;
1101         u16 seqno, rcv_nxt, win_lim;
1102         int rc = 0;
1103
1104         do {
1105                 hdr = buf_msg(skb);
1106                 seqno = msg_seqno(hdr);
1107                 rcv_nxt = l->rcv_nxt;
1108                 win_lim = rcv_nxt + TIPC_MAX_LINK_WIN;
1109
1110                 /* Verify and update link state */
1111                 if (unlikely(msg_user(hdr) == LINK_PROTOCOL))
1112                         return tipc_link_proto_rcv(l, skb, xmitq);
1113
1114                 if (unlikely(!link_is_up(l))) {
1115                         if (l->state == LINK_ESTABLISHING)
1116                                 rc = TIPC_LINK_UP_EVT;
1117                         goto drop;
1118                 }
1119
1120                 /* Don't send probe at next timeout expiration */
1121                 l->silent_intv_cnt = 0;
1122
1123                 /* Drop if outside receive window */
1124                 if (unlikely(less(seqno, rcv_nxt) || more(seqno, win_lim))) {
1125                         l->stats.duplicates++;
1126                         goto drop;
1127                 }
1128
1129                 /* Forward queues and wake up waiting users */
1130                 if (likely(tipc_link_release_pkts(l, msg_ack(hdr)))) {
1131                         tipc_link_advance_backlog(l, xmitq);
1132                         if (unlikely(!skb_queue_empty(&l->wakeupq)))
1133                                 link_prepare_wakeup(l);
1134                 }
1135
1136                 /* Defer delivery if sequence gap */
1137                 if (unlikely(seqno != rcv_nxt)) {
1138                         __tipc_skb_queue_sorted(defq, seqno, skb);
1139                         tipc_link_build_nack_msg(l, xmitq);
1140                         break;
1141                 }
1142
1143                 /* Deliver packet */
1144                 l->rcv_nxt++;
1145                 l->stats.recv_info++;
1146                 if (!tipc_data_input(l, skb, l->inputq))
1147                         rc = tipc_link_input(l, skb, l->inputq);
1148                 if (unlikely(rc))
1149                         break;
1150                 if (unlikely(++l->rcv_unacked >= TIPC_MIN_LINK_WIN))
1151                         tipc_link_build_ack_msg(l, xmitq);
1152
1153         } while ((skb = __skb_dequeue(defq)));
1154
1155         return rc;
1156 drop:
1157         kfree_skb(skb);
1158         return rc;
1159 }
1160
1161 /**
1162  * tipc_link_defer_pkt - Add out-of-sequence message to deferred reception queue
1163  *
1164  * Returns increase in queue length (i.e. 0 or 1)
1165  */
1166 u32 tipc_link_defer_pkt(struct sk_buff_head *list, struct sk_buff *skb)
1167 {
1168         struct sk_buff *skb1;
1169         u16 seq_no = buf_seqno(skb);
1170
1171         /* Empty queue ? */
1172         if (skb_queue_empty(list)) {
1173                 __skb_queue_tail(list, skb);
1174                 return 1;
1175         }
1176
1177         /* Last ? */
1178         if (less(buf_seqno(skb_peek_tail(list)), seq_no)) {
1179                 __skb_queue_tail(list, skb);
1180                 return 1;
1181         }
1182
1183         /* Locate insertion point in queue, then insert; discard if duplicate */
1184         skb_queue_walk(list, skb1) {
1185                 u16 curr_seqno = buf_seqno(skb1);
1186
1187                 if (seq_no == curr_seqno) {
1188                         kfree_skb(skb);
1189                         return 0;
1190                 }
1191
1192                 if (less(seq_no, curr_seqno))
1193                         break;
1194         }
1195
1196         __skb_queue_before(list, skb1, skb);
1197         return 1;
1198 }
1199
1200 /*
1201  * Send protocol message to the other endpoint.
1202  */
1203 void tipc_link_proto_xmit(struct tipc_link *l, u32 msg_typ, int probe_msg,
1204                           u32 gap, u32 tolerance, u32 priority)
1205 {
1206         struct sk_buff *skb = NULL;
1207         struct sk_buff_head xmitq;
1208
1209         __skb_queue_head_init(&xmitq);
1210         tipc_link_build_proto_msg(l, msg_typ, probe_msg, gap,
1211                                   tolerance, priority, &xmitq);
1212         skb = __skb_dequeue(&xmitq);
1213         if (!skb)
1214                 return;
1215         tipc_bearer_send(l->owner->net, l->bearer_id, skb, l->media_addr);
1216         l->rcv_unacked = 0;
1217         kfree_skb(skb);
1218 }
1219
1220 /* tipc_link_build_proto_msg: prepare link protocol message for transmission
1221  */
1222 static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
1223                                       u16 rcvgap, int tolerance, int priority,
1224                                       struct sk_buff_head *xmitq)
1225 {
1226         struct sk_buff *skb = NULL;
1227         struct tipc_msg *hdr = l->pmsg;
1228         u16 snd_nxt = l->snd_nxt;
1229         u16 rcv_nxt = l->rcv_nxt;
1230         u16 rcv_last = rcv_nxt - 1;
1231         int node_up = l->owner->bclink.recv_permitted;
1232
1233         /* Don't send protocol message during reset or link failover */
1234         if (tipc_link_is_blocked(l))
1235                 return;
1236
1237         msg_set_type(hdr, mtyp);
1238         msg_set_net_plane(hdr, l->net_plane);
1239         msg_set_bcast_ack(hdr, l->owner->bclink.last_in);
1240         msg_set_last_bcast(hdr, tipc_bclink_get_last_sent(l->owner->net));
1241         msg_set_link_tolerance(hdr, tolerance);
1242         msg_set_linkprio(hdr, priority);
1243         msg_set_redundant_link(hdr, node_up);
1244         msg_set_seq_gap(hdr, 0);
1245
1246         /* Compatibility: created msg must not be in sequence with pkt flow */
1247         msg_set_seqno(hdr, snd_nxt + U16_MAX / 2);
1248
1249         if (mtyp == STATE_MSG) {
1250                 if (!tipc_link_is_up(l))
1251                         return;
1252                 msg_set_next_sent(hdr, snd_nxt);
1253
1254                 /* Override rcvgap if there are packets in deferred queue */
1255                 if (!skb_queue_empty(&l->deferdq))
1256                         rcvgap = buf_seqno(skb_peek(&l->deferdq)) - rcv_nxt;
1257                 if (rcvgap) {
1258                         msg_set_seq_gap(hdr, rcvgap);
1259                         l->stats.sent_nacks++;
1260                 }
1261                 msg_set_ack(hdr, rcv_last);
1262                 msg_set_probe(hdr, probe);
1263                 if (probe)
1264                         l->stats.sent_probes++;
1265                 l->stats.sent_states++;
1266         } else {
1267                 /* RESET_MSG or ACTIVATE_MSG */
1268                 msg_set_max_pkt(hdr, l->advertised_mtu);
1269                 msg_set_ack(hdr, l->rcv_nxt - 1);
1270                 msg_set_next_sent(hdr, 1);
1271         }
1272         skb = tipc_buf_acquire(msg_size(hdr));
1273         if (!skb)
1274                 return;
1275         skb_copy_to_linear_data(skb, hdr, msg_size(hdr));
1276         skb->priority = TC_PRIO_CONTROL;
1277         __skb_queue_tail(xmitq, skb);
1278 }
1279
1280 /* tipc_link_tnl_prepare(): prepare and return a list of tunnel packets
1281  * with contents of the link's transmit and backlog queues.
1282  */
1283 void tipc_link_tnl_prepare(struct tipc_link *l, struct tipc_link *tnl,
1284                            int mtyp, struct sk_buff_head *xmitq)
1285 {
1286         struct sk_buff *skb, *tnlskb;
1287         struct tipc_msg *hdr, tnlhdr;
1288         struct sk_buff_head *queue = &l->transmq;
1289         struct sk_buff_head tmpxq, tnlq;
1290         u16 pktlen, pktcnt, seqno = l->snd_nxt;
1291
1292         if (!tnl)
1293                 return;
1294
1295         skb_queue_head_init(&tnlq);
1296         skb_queue_head_init(&tmpxq);
1297
1298         /* At least one packet required for safe algorithm => add dummy */
1299         skb = tipc_msg_create(TIPC_LOW_IMPORTANCE, TIPC_DIRECT_MSG,
1300                               BASIC_H_SIZE, 0, l->addr, link_own_addr(l),
1301                               0, 0, TIPC_ERR_NO_PORT);
1302         if (!skb) {
1303                 pr_warn("%sunable to create tunnel packet\n", link_co_err);
1304                 return;
1305         }
1306         skb_queue_tail(&tnlq, skb);
1307         tipc_link_xmit(l, &tnlq, &tmpxq);
1308         __skb_queue_purge(&tmpxq);
1309
1310         /* Initialize reusable tunnel packet header */
1311         tipc_msg_init(link_own_addr(l), &tnlhdr, TUNNEL_PROTOCOL,
1312                       mtyp, INT_H_SIZE, l->addr);
1313         pktcnt = skb_queue_len(&l->transmq) + skb_queue_len(&l->backlogq);
1314         msg_set_msgcnt(&tnlhdr, pktcnt);
1315         msg_set_bearer_id(&tnlhdr, l->peer_bearer_id);
1316 tnl:
1317         /* Wrap each packet into a tunnel packet */
1318         skb_queue_walk(queue, skb) {
1319                 hdr = buf_msg(skb);
1320                 if (queue == &l->backlogq)
1321                         msg_set_seqno(hdr, seqno++);
1322                 pktlen = msg_size(hdr);
1323                 msg_set_size(&tnlhdr, pktlen + INT_H_SIZE);
1324                 tnlskb = tipc_buf_acquire(pktlen + INT_H_SIZE);
1325                 if (!tnlskb) {
1326                         pr_warn("%sunable to send packet\n", link_co_err);
1327                         return;
1328                 }
1329                 skb_copy_to_linear_data(tnlskb, &tnlhdr, INT_H_SIZE);
1330                 skb_copy_to_linear_data_offset(tnlskb, INT_H_SIZE, hdr, pktlen);
1331                 __skb_queue_tail(&tnlq, tnlskb);
1332         }
1333         if (queue != &l->backlogq) {
1334                 queue = &l->backlogq;
1335                 goto tnl;
1336         }
1337
1338         tipc_link_xmit(tnl, &tnlq, xmitq);
1339
1340         if (mtyp == FAILOVER_MSG) {
1341                 tnl->drop_point = l->rcv_nxt;
1342                 tnl->failover_reasm_skb = l->reasm_buf;
1343                 l->reasm_buf = NULL;
1344         }
1345 }
1346
1347 /* tipc_link_proto_rcv(): receive link level protocol message :
1348  * Note that network plane id propagates through the network, and may
1349  * change at any time. The node with lowest numerical id determines
1350  * network plane
1351  */
1352 static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
1353                                struct sk_buff_head *xmitq)
1354 {
1355         struct tipc_msg *hdr = buf_msg(skb);
1356         u16 rcvgap = 0;
1357         u16 nacked_gap = msg_seq_gap(hdr);
1358         u16 peers_snd_nxt =  msg_next_sent(hdr);
1359         u16 peers_tol = msg_link_tolerance(hdr);
1360         u16 peers_prio = msg_linkprio(hdr);
1361         u16 rcv_nxt = l->rcv_nxt;
1362         int mtyp = msg_type(hdr);
1363         char *if_name;
1364         int rc = 0;
1365
1366         if (tipc_link_is_blocked(l))
1367                 goto exit;
1368
1369         if (link_own_addr(l) > msg_prevnode(hdr))
1370                 l->net_plane = msg_net_plane(hdr);
1371
1372         switch (mtyp) {
1373         case RESET_MSG:
1374
1375                 /* Ignore duplicate RESET with old session number */
1376                 if ((less_eq(msg_session(hdr), l->peer_session)) &&
1377                     (l->peer_session != WILDCARD_SESSION))
1378                         break;
1379                 /* fall thru' */
1380
1381         case ACTIVATE_MSG:
1382
1383                 /* Complete own link name with peer's interface name */
1384                 if_name =  strrchr(l->name, ':') + 1;
1385                 if (sizeof(l->name) - (if_name - l->name) <= TIPC_MAX_IF_NAME)
1386                         break;
1387                 if (msg_data_sz(hdr) < TIPC_MAX_IF_NAME)
1388                         break;
1389                 strncpy(if_name, msg_data(hdr), TIPC_MAX_IF_NAME);
1390
1391                 /* Update own tolerance if peer indicates a non-zero value */
1392                 if (in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL))
1393                         l->tolerance = peers_tol;
1394
1395                 /* Update own priority if peer's priority is higher */
1396                 if (in_range(peers_prio, l->priority + 1, TIPC_MAX_LINK_PRI))
1397                         l->priority = peers_prio;
1398
1399                 /* ACTIVATE_MSG serves as PEER_RESET if link is already down */
1400                 if ((mtyp == RESET_MSG) || !link_is_up(l))
1401                         rc = tipc_link_fsm_evt(l, LINK_PEER_RESET_EVT);
1402
1403                 /* ACTIVATE_MSG takes up link if it was already locally reset */
1404                 if ((mtyp == ACTIVATE_MSG) && (l->state == LINK_ESTABLISHING))
1405                         rc = TIPC_LINK_UP_EVT;
1406
1407                 l->peer_session = msg_session(hdr);
1408                 l->peer_bearer_id = msg_bearer_id(hdr);
1409                 if (l->mtu > msg_max_pkt(hdr))
1410                         l->mtu = msg_max_pkt(hdr);
1411                 break;
1412
1413         case STATE_MSG:
1414
1415                 /* Update own tolerance if peer indicates a non-zero value */
1416                 if (in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL))
1417                         l->tolerance = peers_tol;
1418
1419                 l->silent_intv_cnt = 0;
1420                 l->stats.recv_states++;
1421                 if (msg_probe(hdr))
1422                         l->stats.recv_probes++;
1423
1424                 if (!link_is_up(l)) {
1425                         if (l->state == LINK_ESTABLISHING)
1426                                 rc = TIPC_LINK_UP_EVT;
1427                         break;
1428                 }
1429
1430                 /* Send NACK if peer has sent pkts we haven't received yet */
1431                 if (more(peers_snd_nxt, rcv_nxt) && !tipc_link_is_synching(l))
1432                         rcvgap = peers_snd_nxt - l->rcv_nxt;
1433                 if (rcvgap || (msg_probe(hdr)))
1434                         tipc_link_build_proto_msg(l, STATE_MSG, 0, rcvgap,
1435                                                   0, 0, xmitq);
1436                 tipc_link_release_pkts(l, msg_ack(hdr));
1437
1438                 /* If NACK, retransmit will now start at right position */
1439                 if (nacked_gap) {
1440                         rc = tipc_link_retransm(l, nacked_gap, xmitq);
1441                         l->stats.recv_nacks++;
1442                 }
1443
1444                 tipc_link_advance_backlog(l, xmitq);
1445                 if (unlikely(!skb_queue_empty(&l->wakeupq)))
1446                         link_prepare_wakeup(l);
1447         }
1448 exit:
1449         kfree_skb(skb);
1450         return rc;
1451 }
1452
1453 void tipc_link_set_queue_limits(struct tipc_link *l, u32 win)
1454 {
1455         int max_bulk = TIPC_MAX_PUBLICATIONS / (l->mtu / ITEM_SIZE);
1456
1457         l->window = win;
1458         l->backlog[TIPC_LOW_IMPORTANCE].limit      = win / 2;
1459         l->backlog[TIPC_MEDIUM_IMPORTANCE].limit   = win;
1460         l->backlog[TIPC_HIGH_IMPORTANCE].limit     = win / 2 * 3;
1461         l->backlog[TIPC_CRITICAL_IMPORTANCE].limit = win * 2;
1462         l->backlog[TIPC_SYSTEM_IMPORTANCE].limit   = max_bulk;
1463 }
1464
1465 /* tipc_link_find_owner - locate owner node of link by link's name
1466  * @net: the applicable net namespace
1467  * @name: pointer to link name string
1468  * @bearer_id: pointer to index in 'node->links' array where the link was found.
1469  *
1470  * Returns pointer to node owning the link, or 0 if no matching link is found.
1471  */
1472 static struct tipc_node *tipc_link_find_owner(struct net *net,
1473                                               const char *link_name,
1474                                               unsigned int *bearer_id)
1475 {
1476         struct tipc_net *tn = net_generic(net, tipc_net_id);
1477         struct tipc_link *l_ptr;
1478         struct tipc_node *n_ptr;
1479         struct tipc_node *found_node = NULL;
1480         int i;
1481
1482         *bearer_id = 0;
1483         rcu_read_lock();
1484         list_for_each_entry_rcu(n_ptr, &tn->node_list, list) {
1485                 tipc_node_lock(n_ptr);
1486                 for (i = 0; i < MAX_BEARERS; i++) {
1487                         l_ptr = n_ptr->links[i].link;
1488                         if (l_ptr && !strcmp(l_ptr->name, link_name)) {
1489                                 *bearer_id = i;
1490                                 found_node = n_ptr;
1491                                 break;
1492                         }
1493                 }
1494                 tipc_node_unlock(n_ptr);
1495                 if (found_node)
1496                         break;
1497         }
1498         rcu_read_unlock();
1499
1500         return found_node;
1501 }
1502
1503 /**
1504  * link_reset_statistics - reset link statistics
1505  * @l_ptr: pointer to link
1506  */
1507 static void link_reset_statistics(struct tipc_link *l_ptr)
1508 {
1509         memset(&l_ptr->stats, 0, sizeof(l_ptr->stats));
1510         l_ptr->stats.sent_info = l_ptr->snd_nxt;
1511         l_ptr->stats.recv_info = l_ptr->rcv_nxt;
1512 }
1513
1514 static void link_print(struct tipc_link *l, const char *str)
1515 {
1516         struct sk_buff *hskb = skb_peek(&l->transmq);
1517         u16 head = hskb ? msg_seqno(buf_msg(hskb)) : l->snd_nxt;
1518         u16 tail = l->snd_nxt - 1;
1519
1520         pr_info("%s Link <%s> state %x\n", str, l->name, l->state);
1521         pr_info("XMTQ: %u [%u-%u], BKLGQ: %u, SNDNX: %u, RCVNX: %u\n",
1522                 skb_queue_len(&l->transmq), head, tail,
1523                 skb_queue_len(&l->backlogq), l->snd_nxt, l->rcv_nxt);
1524 }
1525
1526 /* Parse and validate nested (link) properties valid for media, bearer and link
1527  */
1528 int tipc_nl_parse_link_prop(struct nlattr *prop, struct nlattr *props[])
1529 {
1530         int err;
1531
1532         err = nla_parse_nested(props, TIPC_NLA_PROP_MAX, prop,
1533                                tipc_nl_prop_policy);
1534         if (err)
1535                 return err;
1536
1537         if (props[TIPC_NLA_PROP_PRIO]) {
1538                 u32 prio;
1539
1540                 prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
1541                 if (prio > TIPC_MAX_LINK_PRI)
1542                         return -EINVAL;
1543         }
1544
1545         if (props[TIPC_NLA_PROP_TOL]) {
1546                 u32 tol;
1547
1548                 tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
1549                 if ((tol < TIPC_MIN_LINK_TOL) || (tol > TIPC_MAX_LINK_TOL))
1550                         return -EINVAL;
1551         }
1552
1553         if (props[TIPC_NLA_PROP_WIN]) {
1554                 u32 win;
1555
1556                 win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
1557                 if ((win < TIPC_MIN_LINK_WIN) || (win > TIPC_MAX_LINK_WIN))
1558                         return -EINVAL;
1559         }
1560
1561         return 0;
1562 }
1563
1564 int tipc_nl_link_set(struct sk_buff *skb, struct genl_info *info)
1565 {
1566         int err;
1567         int res = 0;
1568         int bearer_id;
1569         char *name;
1570         struct tipc_link *link;
1571         struct tipc_node *node;
1572         struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
1573         struct net *net = sock_net(skb->sk);
1574
1575         if (!info->attrs[TIPC_NLA_LINK])
1576                 return -EINVAL;
1577
1578         err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
1579                                info->attrs[TIPC_NLA_LINK],
1580                                tipc_nl_link_policy);
1581         if (err)
1582                 return err;
1583
1584         if (!attrs[TIPC_NLA_LINK_NAME])
1585                 return -EINVAL;
1586
1587         name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
1588
1589         if (strcmp(name, tipc_bclink_name) == 0)
1590                 return tipc_nl_bc_link_set(net, attrs);
1591
1592         node = tipc_link_find_owner(net, name, &bearer_id);
1593         if (!node)
1594                 return -EINVAL;
1595
1596         tipc_node_lock(node);
1597
1598         link = node->links[bearer_id].link;
1599         if (!link) {
1600                 res = -EINVAL;
1601                 goto out;
1602         }
1603
1604         if (attrs[TIPC_NLA_LINK_PROP]) {
1605                 struct nlattr *props[TIPC_NLA_PROP_MAX + 1];
1606
1607                 err = tipc_nl_parse_link_prop(attrs[TIPC_NLA_LINK_PROP],
1608                                               props);
1609                 if (err) {
1610                         res = err;
1611                         goto out;
1612                 }
1613
1614                 if (props[TIPC_NLA_PROP_TOL]) {
1615                         u32 tol;
1616
1617                         tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
1618                         link->tolerance = tol;
1619                         tipc_link_proto_xmit(link, STATE_MSG, 0, 0, tol, 0);
1620                 }
1621                 if (props[TIPC_NLA_PROP_PRIO]) {
1622                         u32 prio;
1623
1624                         prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
1625                         link->priority = prio;
1626                         tipc_link_proto_xmit(link, STATE_MSG, 0, 0, 0, prio);
1627                 }
1628                 if (props[TIPC_NLA_PROP_WIN]) {
1629                         u32 win;
1630
1631                         win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
1632                         tipc_link_set_queue_limits(link, win);
1633                 }
1634         }
1635
1636 out:
1637         tipc_node_unlock(node);
1638
1639         return res;
1640 }
1641
1642 static int __tipc_nl_add_stats(struct sk_buff *skb, struct tipc_stats *s)
1643 {
1644         int i;
1645         struct nlattr *stats;
1646
1647         struct nla_map {
1648                 u32 key;
1649                 u32 val;
1650         };
1651
1652         struct nla_map map[] = {
1653                 {TIPC_NLA_STATS_RX_INFO, s->recv_info},
1654                 {TIPC_NLA_STATS_RX_FRAGMENTS, s->recv_fragments},
1655                 {TIPC_NLA_STATS_RX_FRAGMENTED, s->recv_fragmented},
1656                 {TIPC_NLA_STATS_RX_BUNDLES, s->recv_bundles},
1657                 {TIPC_NLA_STATS_RX_BUNDLED, s->recv_bundled},
1658                 {TIPC_NLA_STATS_TX_INFO, s->sent_info},
1659                 {TIPC_NLA_STATS_TX_FRAGMENTS, s->sent_fragments},
1660                 {TIPC_NLA_STATS_TX_FRAGMENTED, s->sent_fragmented},
1661                 {TIPC_NLA_STATS_TX_BUNDLES, s->sent_bundles},
1662                 {TIPC_NLA_STATS_TX_BUNDLED, s->sent_bundled},
1663                 {TIPC_NLA_STATS_MSG_PROF_TOT, (s->msg_length_counts) ?
1664                         s->msg_length_counts : 1},
1665                 {TIPC_NLA_STATS_MSG_LEN_CNT, s->msg_length_counts},
1666                 {TIPC_NLA_STATS_MSG_LEN_TOT, s->msg_lengths_total},
1667                 {TIPC_NLA_STATS_MSG_LEN_P0, s->msg_length_profile[0]},
1668                 {TIPC_NLA_STATS_MSG_LEN_P1, s->msg_length_profile[1]},
1669                 {TIPC_NLA_STATS_MSG_LEN_P2, s->msg_length_profile[2]},
1670                 {TIPC_NLA_STATS_MSG_LEN_P3, s->msg_length_profile[3]},
1671                 {TIPC_NLA_STATS_MSG_LEN_P4, s->msg_length_profile[4]},
1672                 {TIPC_NLA_STATS_MSG_LEN_P5, s->msg_length_profile[5]},
1673                 {TIPC_NLA_STATS_MSG_LEN_P6, s->msg_length_profile[6]},
1674                 {TIPC_NLA_STATS_RX_STATES, s->recv_states},
1675                 {TIPC_NLA_STATS_RX_PROBES, s->recv_probes},
1676                 {TIPC_NLA_STATS_RX_NACKS, s->recv_nacks},
1677                 {TIPC_NLA_STATS_RX_DEFERRED, s->deferred_recv},
1678                 {TIPC_NLA_STATS_TX_STATES, s->sent_states},
1679                 {TIPC_NLA_STATS_TX_PROBES, s->sent_probes},
1680                 {TIPC_NLA_STATS_TX_NACKS, s->sent_nacks},
1681                 {TIPC_NLA_STATS_TX_ACKS, s->sent_acks},
1682                 {TIPC_NLA_STATS_RETRANSMITTED, s->retransmitted},
1683                 {TIPC_NLA_STATS_DUPLICATES, s->duplicates},
1684                 {TIPC_NLA_STATS_LINK_CONGS, s->link_congs},
1685                 {TIPC_NLA_STATS_MAX_QUEUE, s->max_queue_sz},
1686                 {TIPC_NLA_STATS_AVG_QUEUE, s->queue_sz_counts ?
1687                         (s->accu_queue_sz / s->queue_sz_counts) : 0}
1688         };
1689
1690         stats = nla_nest_start(skb, TIPC_NLA_LINK_STATS);
1691         if (!stats)
1692                 return -EMSGSIZE;
1693
1694         for (i = 0; i <  ARRAY_SIZE(map); i++)
1695                 if (nla_put_u32(skb, map[i].key, map[i].val))
1696                         goto msg_full;
1697
1698         nla_nest_end(skb, stats);
1699
1700         return 0;
1701 msg_full:
1702         nla_nest_cancel(skb, stats);
1703
1704         return -EMSGSIZE;
1705 }
1706
1707 /* Caller should hold appropriate locks to protect the link */
1708 static int __tipc_nl_add_link(struct net *net, struct tipc_nl_msg *msg,
1709                               struct tipc_link *link, int nlflags)
1710 {
1711         int err;
1712         void *hdr;
1713         struct nlattr *attrs;
1714         struct nlattr *prop;
1715         struct tipc_net *tn = net_generic(net, tipc_net_id);
1716
1717         hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
1718                           nlflags, TIPC_NL_LINK_GET);
1719         if (!hdr)
1720                 return -EMSGSIZE;
1721
1722         attrs = nla_nest_start(msg->skb, TIPC_NLA_LINK);
1723         if (!attrs)
1724                 goto msg_full;
1725
1726         if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, link->name))
1727                 goto attr_msg_full;
1728         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_DEST,
1729                         tipc_cluster_mask(tn->own_addr)))
1730                 goto attr_msg_full;
1731         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_MTU, link->mtu))
1732                 goto attr_msg_full;
1733         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, link->rcv_nxt))
1734                 goto attr_msg_full;
1735         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, link->snd_nxt))
1736                 goto attr_msg_full;
1737
1738         if (tipc_link_is_up(link))
1739                 if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
1740                         goto attr_msg_full;
1741         if (tipc_link_is_active(link))
1742                 if (nla_put_flag(msg->skb, TIPC_NLA_LINK_ACTIVE))
1743                         goto attr_msg_full;
1744
1745         prop = nla_nest_start(msg->skb, TIPC_NLA_LINK_PROP);
1746         if (!prop)
1747                 goto attr_msg_full;
1748         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
1749                 goto prop_msg_full;
1750         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_TOL, link->tolerance))
1751                 goto prop_msg_full;
1752         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN,
1753                         link->window))
1754                 goto prop_msg_full;
1755         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
1756                 goto prop_msg_full;
1757         nla_nest_end(msg->skb, prop);
1758
1759         err = __tipc_nl_add_stats(msg->skb, &link->stats);
1760         if (err)
1761                 goto attr_msg_full;
1762
1763         nla_nest_end(msg->skb, attrs);
1764         genlmsg_end(msg->skb, hdr);
1765
1766         return 0;
1767
1768 prop_msg_full:
1769         nla_nest_cancel(msg->skb, prop);
1770 attr_msg_full:
1771         nla_nest_cancel(msg->skb, attrs);
1772 msg_full:
1773         genlmsg_cancel(msg->skb, hdr);
1774
1775         return -EMSGSIZE;
1776 }
1777
1778 /* Caller should hold node lock  */
1779 static int __tipc_nl_add_node_links(struct net *net, struct tipc_nl_msg *msg,
1780                                     struct tipc_node *node, u32 *prev_link)
1781 {
1782         u32 i;
1783         int err;
1784
1785         for (i = *prev_link; i < MAX_BEARERS; i++) {
1786                 *prev_link = i;
1787
1788                 if (!node->links[i].link)
1789                         continue;
1790
1791                 err = __tipc_nl_add_link(net, msg,
1792                                          node->links[i].link, NLM_F_MULTI);
1793                 if (err)
1794                         return err;
1795         }
1796         *prev_link = 0;
1797
1798         return 0;
1799 }
1800
1801 int tipc_nl_link_dump(struct sk_buff *skb, struct netlink_callback *cb)
1802 {
1803         struct net *net = sock_net(skb->sk);
1804         struct tipc_net *tn = net_generic(net, tipc_net_id);
1805         struct tipc_node *node;
1806         struct tipc_nl_msg msg;
1807         u32 prev_node = cb->args[0];
1808         u32 prev_link = cb->args[1];
1809         int done = cb->args[2];
1810         int err;
1811
1812         if (done)
1813                 return 0;
1814
1815         msg.skb = skb;
1816         msg.portid = NETLINK_CB(cb->skb).portid;
1817         msg.seq = cb->nlh->nlmsg_seq;
1818
1819         rcu_read_lock();
1820         if (prev_node) {
1821                 node = tipc_node_find(net, prev_node);
1822                 if (!node) {
1823                         /* We never set seq or call nl_dump_check_consistent()
1824                          * this means that setting prev_seq here will cause the
1825                          * consistence check to fail in the netlink callback
1826                          * handler. Resulting in the last NLMSG_DONE message
1827                          * having the NLM_F_DUMP_INTR flag set.
1828                          */
1829                         cb->prev_seq = 1;
1830                         goto out;
1831                 }
1832                 tipc_node_put(node);
1833
1834                 list_for_each_entry_continue_rcu(node, &tn->node_list,
1835                                                  list) {
1836                         tipc_node_lock(node);
1837                         err = __tipc_nl_add_node_links(net, &msg, node,
1838                                                        &prev_link);
1839                         tipc_node_unlock(node);
1840                         if (err)
1841                                 goto out;
1842
1843                         prev_node = node->addr;
1844                 }
1845         } else {
1846                 err = tipc_nl_add_bc_link(net, &msg);
1847                 if (err)
1848                         goto out;
1849
1850                 list_for_each_entry_rcu(node, &tn->node_list, list) {
1851                         tipc_node_lock(node);
1852                         err = __tipc_nl_add_node_links(net, &msg, node,
1853                                                        &prev_link);
1854                         tipc_node_unlock(node);
1855                         if (err)
1856                                 goto out;
1857
1858                         prev_node = node->addr;
1859                 }
1860         }
1861         done = 1;
1862 out:
1863         rcu_read_unlock();
1864
1865         cb->args[0] = prev_node;
1866         cb->args[1] = prev_link;
1867         cb->args[2] = done;
1868
1869         return skb->len;
1870 }
1871
1872 int tipc_nl_link_get(struct sk_buff *skb, struct genl_info *info)
1873 {
1874         struct net *net = genl_info_net(info);
1875         struct tipc_nl_msg msg;
1876         char *name;
1877         int err;
1878
1879         msg.portid = info->snd_portid;
1880         msg.seq = info->snd_seq;
1881
1882         if (!info->attrs[TIPC_NLA_LINK_NAME])
1883                 return -EINVAL;
1884         name = nla_data(info->attrs[TIPC_NLA_LINK_NAME]);
1885
1886         msg.skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
1887         if (!msg.skb)
1888                 return -ENOMEM;
1889
1890         if (strcmp(name, tipc_bclink_name) == 0) {
1891                 err = tipc_nl_add_bc_link(net, &msg);
1892                 if (err) {
1893                         nlmsg_free(msg.skb);
1894                         return err;
1895                 }
1896         } else {
1897                 int bearer_id;
1898                 struct tipc_node *node;
1899                 struct tipc_link *link;
1900
1901                 node = tipc_link_find_owner(net, name, &bearer_id);
1902                 if (!node)
1903                         return -EINVAL;
1904
1905                 tipc_node_lock(node);
1906                 link = node->links[bearer_id].link;
1907                 if (!link) {
1908                         tipc_node_unlock(node);
1909                         nlmsg_free(msg.skb);
1910                         return -EINVAL;
1911                 }
1912
1913                 err = __tipc_nl_add_link(net, &msg, link, 0);
1914                 tipc_node_unlock(node);
1915                 if (err) {
1916                         nlmsg_free(msg.skb);
1917                         return err;
1918                 }
1919         }
1920
1921         return genlmsg_reply(msg.skb, info);
1922 }
1923
1924 int tipc_nl_link_reset_stats(struct sk_buff *skb, struct genl_info *info)
1925 {
1926         int err;
1927         char *link_name;
1928         unsigned int bearer_id;
1929         struct tipc_link *link;
1930         struct tipc_node *node;
1931         struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
1932         struct net *net = sock_net(skb->sk);
1933
1934         if (!info->attrs[TIPC_NLA_LINK])
1935                 return -EINVAL;
1936
1937         err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
1938                                info->attrs[TIPC_NLA_LINK],
1939                                tipc_nl_link_policy);
1940         if (err)
1941                 return err;
1942
1943         if (!attrs[TIPC_NLA_LINK_NAME])
1944                 return -EINVAL;
1945
1946         link_name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
1947
1948         if (strcmp(link_name, tipc_bclink_name) == 0) {
1949                 err = tipc_bclink_reset_stats(net);
1950                 if (err)
1951                         return err;
1952                 return 0;
1953         }
1954
1955         node = tipc_link_find_owner(net, link_name, &bearer_id);
1956         if (!node)
1957                 return -EINVAL;
1958
1959         tipc_node_lock(node);
1960
1961         link = node->links[bearer_id].link;
1962         if (!link) {
1963                 tipc_node_unlock(node);
1964                 return -EINVAL;
1965         }
1966
1967         link_reset_statistics(link);
1968
1969         tipc_node_unlock(node);
1970
1971         return 0;
1972 }