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