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  * @if_name: associated interface name
 169  * @bearer_id: id (index) of associated bearer
 170  * @tolerance: link tolerance to be used by link
 171  * @net_plane: network plane (A,B,c..) this link belongs to
 172  * @mtu: mtu to be advertised by link
 173  * @priority: priority to be used by link
 174  * @window: send window to be used by link
 175  * @session: session to be used by link
 176  * @ownnode: identity of own node
 177  * @peer: node id of peer node
 178  * @maddr: media address to be used
 179  * @inputq: queue to put messages ready for delivery
 180  * @namedq: queue to put binding table update messages ready for delivery
 181  * @link: return value, pointer to put the created link
 182  *
 183  * Returns true if link was created, otherwise false
 184  */
 185 bool tipc_link_create(struct tipc_node *n, char *if_name, int bearer_id,
 186                       int tolerance, char net_plane, u32 mtu, int priority,
 187                       int window, u32 session, u32 ownnode, u32 peer,
 188                       struct tipc_media_addr *maddr,
 189                       struct sk_buff_head *inputq, struct sk_buff_head *namedq,
 190                       struct tipc_link **link)
 191 {
 192         struct tipc_link *l;
 193         struct tipc_msg *hdr;
 194
 195         l = kzalloc(sizeof(*l), GFP_ATOMIC);
 196         if (!l)
 197                 return false;
 198         *link = l;
 199         l->pmsg = (struct tipc_msg *)&l->proto_msg;
 200         hdr = l->pmsg;
 201         tipc_msg_init(ownnode, hdr, LINK_PROTOCOL, RESET_MSG, INT_H_SIZE, peer);
 202         msg_set_size(hdr, sizeof(l->proto_msg));
 203         msg_set_session(hdr, session);
 204         msg_set_bearer_id(hdr, l->bearer_id);
 205
 206         /* Note: peer i/f name is completed by reset/activate message */
 207         sprintf(l->name, "%u.%u.%u:%s-%u.%u.%u:unknown",
 208                 tipc_zone(ownnode), tipc_cluster(ownnode), tipc_node(ownnode),
 209                 if_name, tipc_zone(peer), tipc_cluster(peer), tipc_node(peer));
 210         strcpy((char *)msg_data(hdr), if_name);
 211
 212         l->addr = peer;
 213         l->media_addr = maddr;
 214         l->owner = n;
 215         l->peer_session = WILDCARD_SESSION;
 216         l->bearer_id = bearer_id;
 217         l->tolerance = tolerance;
 218         l->net_plane = net_plane;
 219         l->advertised_mtu = mtu;
 220         l->mtu = mtu;
 221         l->priority = priority;
 222         tipc_link_set_queue_limits(l, window);
 223         l->inputq = inputq;
 224         l->namedq = namedq;
 225         l->state = LINK_RESETTING;
 226         __skb_queue_head_init(&l->transmq);
 227         __skb_queue_head_init(&l->backlogq);
 228         __skb_queue_head_init(&l->deferdq);
 229         skb_queue_head_init(&l->wakeupq);
 230         skb_queue_head_init(l->inputq);
 231         return true;
 232 }
 233
 234 /* tipc_link_build_bcast_sync_msg() - synchronize broadcast link endpoints.
 235  *
 236  * Give a newly added peer node the sequence number where it should
 237  * start receiving and acking broadcast packets.
 238  */
 239 void tipc_link_build_bcast_sync_msg(struct tipc_link *l,
 240                                     struct sk_buff_head *xmitq)
 241 {
 242         struct sk_buff *skb;
 243         struct sk_buff_head list;
 244         u16 last_sent;
 245
 246         skb = tipc_msg_create(BCAST_PROTOCOL, STATE_MSG, INT_H_SIZE,
 247                               0, l->addr, link_own_addr(l), 0, 0, 0);
 248         if (!skb)
 249                 return;
 250         last_sent = tipc_bclink_get_last_sent(l->owner->net);
 251         msg_set_last_bcast(buf_msg(skb), last_sent);
 252         __skb_queue_head_init(&list);
 253         __skb_queue_tail(&list, skb);
 254         tipc_link_xmit(l, &list, xmitq);
 255 }
 256
 257 /**
 258  * tipc_link_fsm_evt - link finite state machine
 259  * @l: pointer to link
 260  * @evt: state machine event to be processed
 261  */
 262 int tipc_link_fsm_evt(struct tipc_link *l, int evt)
 263 {
 264         int rc = 0;
 265
 266         switch (l->state) {
 267         case LINK_RESETTING:
 268                 switch (evt) {
 269                 case LINK_PEER_RESET_EVT:
 270                         l->state = LINK_PEER_RESET;
 271                         break;
 272                 case LINK_RESET_EVT:
 273                         l->state = LINK_RESET;
 274                         break;
 275                 case LINK_FAILURE_EVT:
 276                 case LINK_FAILOVER_BEGIN_EVT:
 277                 case LINK_ESTABLISH_EVT:
 278                 case LINK_FAILOVER_END_EVT:
 279                 case LINK_SYNCH_BEGIN_EVT:
 280                 case LINK_SYNCH_END_EVT:
 281                 default:
 282                         goto illegal_evt;
 283                 }
 284                 break;
 285         case LINK_RESET:
 286                 switch (evt) {
 287                 case LINK_PEER_RESET_EVT:
 288                         l->state = LINK_ESTABLISHING;
 289                         break;
 290                 case LINK_FAILOVER_BEGIN_EVT:
 291                         l->state = LINK_FAILINGOVER;
 292                 case LINK_FAILURE_EVT:
 293                 case LINK_RESET_EVT:
 294                 case LINK_ESTABLISH_EVT:
 295                 case LINK_FAILOVER_END_EVT:
 296                         break;
 297                 case LINK_SYNCH_BEGIN_EVT:
 298                 case LINK_SYNCH_END_EVT:
 299                 default:
 300                         goto illegal_evt;
 301                 }
 302                 break;
 303         case LINK_PEER_RESET:
 304                 switch (evt) {
 305                 case LINK_RESET_EVT:
 306                         l->state = LINK_ESTABLISHING;
 307                         break;
 308                 case LINK_PEER_RESET_EVT:
 309                 case LINK_ESTABLISH_EVT:
 310                 case LINK_FAILURE_EVT:
 311                         break;
 312                 case LINK_SYNCH_BEGIN_EVT:
 313                 case LINK_SYNCH_END_EVT:
 314                 case LINK_FAILOVER_BEGIN_EVT:
 315                 case LINK_FAILOVER_END_EVT:
 316                 default:
 317                         goto illegal_evt;
 318                 }
 319                 break;
 320         case LINK_FAILINGOVER:
 321                 switch (evt) {
 322                 case LINK_FAILOVER_END_EVT:
 323                         l->state = LINK_RESET;
 324                         break;
 325                 case LINK_PEER_RESET_EVT:
 326                 case LINK_RESET_EVT:
 327                 case LINK_ESTABLISH_EVT:
 328                 case LINK_FAILURE_EVT:
 329                         break;
 330                 case LINK_FAILOVER_BEGIN_EVT:
 331                 case LINK_SYNCH_BEGIN_EVT:
 332                 case LINK_SYNCH_END_EVT:
 333                 default:
 334                         goto illegal_evt;
 335                 }
 336                 break;
 337         case LINK_ESTABLISHING:
 338                 switch (evt) {
 339                 case LINK_ESTABLISH_EVT:
 340                         l->state = LINK_ESTABLISHED;
 341                         break;
 342                 case LINK_FAILOVER_BEGIN_EVT:
 343                         l->state = LINK_FAILINGOVER;
 344                         break;
 345                 case LINK_RESET_EVT:
 346                         l->state = LINK_RESET;
 347                         break;
 348                 case LINK_FAILURE_EVT:
 349                 case LINK_PEER_RESET_EVT:
 350                 case LINK_SYNCH_BEGIN_EVT:
 351                 case LINK_FAILOVER_END_EVT:
 352                         break;
 353                 case LINK_SYNCH_END_EVT:
 354                 default:
 355                         goto illegal_evt;
 356                 }
 357                 break;
 358         case LINK_ESTABLISHED:
 359                 switch (evt) {
 360                 case LINK_PEER_RESET_EVT:
 361                         l->state = LINK_PEER_RESET;
 362                         rc |= TIPC_LINK_DOWN_EVT;
 363                         break;
 364                 case LINK_FAILURE_EVT:
 365                         l->state = LINK_RESETTING;
 366                         rc |= TIPC_LINK_DOWN_EVT;
 367                         break;
 368                 case LINK_RESET_EVT:
 369                         l->state = LINK_RESET;
 370                         break;
 371                 case LINK_ESTABLISH_EVT:
 372                 case LINK_SYNCH_END_EVT:
 373                         break;
 374                 case LINK_SYNCH_BEGIN_EVT:
 375                         l->state = LINK_SYNCHING;
 376                         break;
 377                 case LINK_FAILOVER_BEGIN_EVT:
 378                 case LINK_FAILOVER_END_EVT:
 379                 default:
 380                         goto illegal_evt;
 381                 }
 382                 break;
 383         case LINK_SYNCHING:
 384                 switch (evt) {
 385                 case LINK_PEER_RESET_EVT:
 386                         l->state = LINK_PEER_RESET;
 387                         rc |= TIPC_LINK_DOWN_EVT;
 388                         break;
 389                 case LINK_FAILURE_EVT:
 390                         l->state = LINK_RESETTING;
 391                         rc |= TIPC_LINK_DOWN_EVT;
 392                         break;
 393                 case LINK_RESET_EVT:
 394                         l->state = LINK_RESET;
 395                         break;
 396                 case LINK_ESTABLISH_EVT:
 397                 case LINK_SYNCH_BEGIN_EVT:
 398                         break;
 399                 case LINK_SYNCH_END_EVT:
 400                         l->state = LINK_ESTABLISHED;
 401                         break;
 402                 case LINK_FAILOVER_BEGIN_EVT:
 403                 case LINK_FAILOVER_END_EVT:
 404                 default:
 405                         goto illegal_evt;
 406                 }
 407                 break;
 408         default:
 409                 pr_err("Unknown FSM state %x in %s\n", l->state, l->name);
 410         }
 411         return rc;
 412 illegal_evt:
 413         pr_err("Illegal FSM event %x in state %x on link %s\n",
 414                evt, l->state, l->name);
 415         return rc;
 416 }
 417
 418 /* link_profile_stats - update statistical profiling of traffic
 419  */
 420 static void link_profile_stats(struct tipc_link *l)
 421 {
 422         struct sk_buff *skb;
 423         struct tipc_msg *msg;
 424         int length;
 425
 426         /* Update counters used in statistical profiling of send traffic */
 427         l->stats.accu_queue_sz += skb_queue_len(&l->transmq);
 428         l->stats.queue_sz_counts++;
 429
 430         skb = skb_peek(&l->transmq);
 431         if (!skb)
 432                 return;
 433         msg = buf_msg(skb);
 434         length = msg_size(msg);
 435
 436         if (msg_user(msg) == MSG_FRAGMENTER) {
 437                 if (msg_type(msg) != FIRST_FRAGMENT)
 438                         return;
 439                 length = msg_size(msg_get_wrapped(msg));
 440         }
 441         l->stats.msg_lengths_total += length;
 442         l->stats.msg_length_counts++;
 443         if (length <= 64)
 444                 l->stats.msg_length_profile[0]++;
 445         else if (length <= 256)
 446                 l->stats.msg_length_profile[1]++;
 447         else if (length <= 1024)
 448                 l->stats.msg_length_profile[2]++;
 449         else if (length <= 4096)
 450                 l->stats.msg_length_profile[3]++;
 451         else if (length <= 16384)
 452                 l->stats.msg_length_profile[4]++;
 453         else if (length <= 32768)
 454                 l->stats.msg_length_profile[5]++;
 455         else
 456                 l->stats.msg_length_profile[6]++;
 457 }
 458
 459 /* tipc_link_timeout - perform periodic task as instructed from node timeout
 460  */
 461 int tipc_link_timeout(struct tipc_link *l, struct sk_buff_head *xmitq)
 462 {
 463         int rc = 0;
 464         int mtyp = STATE_MSG;
 465         bool xmit = false;
 466         bool prb = false;
 467
 468         link_profile_stats(l);
 469
 470         switch (l->state) {
 471         case LINK_ESTABLISHED:
 472         case LINK_SYNCHING:
 473                 if (!l->silent_intv_cnt) {
 474                         if (tipc_bclink_acks_missing(l->owner))
 475                                 xmit = true;
 476                 } else if (l->silent_intv_cnt <= l->abort_limit) {
 477                         xmit = true;
 478                         prb = true;
 479                 } else {
 480                         rc |= tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
 481                 }
 482                 l->silent_intv_cnt++;
 483                 break;
 484         case LINK_RESET:
 485                 xmit = true;
 486                 mtyp = RESET_MSG;
 487                 break;
 488         case LINK_ESTABLISHING:
 489                 xmit = true;
 490                 mtyp = ACTIVATE_MSG;
 491                 break;
 492         case LINK_PEER_RESET:
 493         case LINK_RESETTING:
 494         case LINK_FAILINGOVER:
 495                 break;
 496         default:
 497                 break;
 498         }
 499
 500         if (xmit)
 501                 tipc_link_build_proto_msg(l, mtyp, prb, 0, 0, 0, xmitq);
 502
 503         return rc;
 504 }
 505
 506 /**
 507  * link_schedule_user - schedule a message sender for wakeup after congestion
 508  * @link: congested link
 509  * @list: message that was attempted sent
 510  * Create pseudo msg to send back to user when congestion abates
 511  * Does not consume buffer list
 512  */
 513 static int link_schedule_user(struct tipc_link *link, struct sk_buff_head *list)
 514 {
 515         struct tipc_msg *msg = buf_msg(skb_peek(list));
 516         int imp = msg_importance(msg);
 517         u32 oport = msg_origport(msg);
 518         u32 addr = link_own_addr(link);
 519         struct sk_buff *skb;
 520
 521         /* This really cannot happen...  */
 522         if (unlikely(imp > TIPC_CRITICAL_IMPORTANCE)) {
 523                 pr_warn("%s<%s>, send queue full", link_rst_msg, link->name);
 524                 return -ENOBUFS;
 525         }
 526         /* Non-blocking sender: */
 527         if (TIPC_SKB_CB(skb_peek(list))->wakeup_pending)
 528                 return -ELINKCONG;
 529
 530         /* Create and schedule wakeup pseudo message */
 531         skb = tipc_msg_create(SOCK_WAKEUP, 0, INT_H_SIZE, 0,
 532                               addr, addr, oport, 0, 0);
 533         if (!skb)
 534                 return -ENOBUFS;
 535         TIPC_SKB_CB(skb)->chain_sz = skb_queue_len(list);
 536         TIPC_SKB_CB(skb)->chain_imp = imp;
 537         skb_queue_tail(&link->wakeupq, skb);
 538         link->stats.link_congs++;
 539         return -ELINKCONG;
 540 }
 541
 542 /**
 543  * link_prepare_wakeup - prepare users for wakeup after congestion
 544  * @link: congested link
 545  * Move a number of waiting users, as permitted by available space in
 546  * the send queue, from link wait queue to node wait queue for wakeup
 547  */
 548 void link_prepare_wakeup(struct tipc_link *l)
 549 {
 550         int pnd[TIPC_SYSTEM_IMPORTANCE + 1] = {0,};
 551         int imp, lim;
 552         struct sk_buff *skb, *tmp;
 553
 554         skb_queue_walk_safe(&l->wakeupq, skb, tmp) {
 555                 imp = TIPC_SKB_CB(skb)->chain_imp;
 556                 lim = l->window + l->backlog[imp].limit;
 557                 pnd[imp] += TIPC_SKB_CB(skb)->chain_sz;
 558                 if ((pnd[imp] + l->backlog[imp].len) >= lim)
 559                         break;
 560                 skb_unlink(skb, &l->wakeupq);
 561                 skb_queue_tail(l->inputq, skb);
 562         }
 563 }
 564
 565 /**
 566  * tipc_link_reset_fragments - purge link's inbound message fragments queue
 567  * @l_ptr: pointer to link
 568  */
 569 void tipc_link_reset_fragments(struct tipc_link *l_ptr)
 570 {
 571         kfree_skb(l_ptr->reasm_buf);
 572         l_ptr->reasm_buf = NULL;
 573 }
 574
 575 void tipc_link_purge_backlog(struct tipc_link *l)
 576 {
 577         __skb_queue_purge(&l->backlogq);
 578         l->backlog[TIPC_LOW_IMPORTANCE].len = 0;
 579         l->backlog[TIPC_MEDIUM_IMPORTANCE].len = 0;
 580         l->backlog[TIPC_HIGH_IMPORTANCE].len = 0;
 581         l->backlog[TIPC_CRITICAL_IMPORTANCE].len = 0;
 582         l->backlog[TIPC_SYSTEM_IMPORTANCE].len = 0;
 583 }
 584
 585 /**
 586  * tipc_link_purge_queues - purge all pkt queues associated with link
 587  * @l_ptr: pointer to link
 588  */
 589 void tipc_link_purge_queues(struct tipc_link *l_ptr)
 590 {
 591         __skb_queue_purge(&l_ptr->deferdq);
 592         __skb_queue_purge(&l_ptr->transmq);
 593         tipc_link_purge_backlog(l_ptr);
 594         tipc_link_reset_fragments(l_ptr);
 595 }
 596
 597 void tipc_link_reset(struct tipc_link *l)
 598 {
 599         /* Link is down, accept any session */
 600         l->peer_session = WILDCARD_SESSION;
 601
 602         /* If peer is up, it only accepts an incremented session number */
 603         msg_set_session(l->pmsg, msg_session(l->pmsg) + 1);
 604
 605         /* Prepare for renewed mtu size negotiation */
 606         l->mtu = l->advertised_mtu;
 607
 608         /* Clean up all queues: */
 609         __skb_queue_purge(&l->transmq);
 610         __skb_queue_purge(&l->deferdq);
 611         skb_queue_splice_init(&l->wakeupq, l->inputq);
 612
 613         tipc_link_purge_backlog(l);
 614         kfree_skb(l->reasm_buf);
 615         kfree_skb(l->failover_reasm_skb);
 616         l->reasm_buf = NULL;
 617         l->failover_reasm_skb = NULL;
 618         l->rcv_unacked = 0;
 619         l->snd_nxt = 1;
 620         l->rcv_nxt = 1;
 621         l->silent_intv_cnt = 0;
 622         l->stats.recv_info = 0;
 623         l->stale_count = 0;
 624         link_reset_statistics(l);
 625 }
 626
 627 /**
 628  * __tipc_link_xmit(): same as tipc_link_xmit, but destlink is known & locked
 629  * @link: link to use
 630  * @list: chain of buffers containing message
 631  *
 632  * Consumes the buffer chain, except when returning an error code,
 633  * Returns 0 if success, or errno: -ELINKCONG, -EMSGSIZE or -ENOBUFS
 634  * Messages at TIPC_SYSTEM_IMPORTANCE are always accepted
 635  */
 636 int __tipc_link_xmit(struct net *net, struct tipc_link *link,
 637                      struct sk_buff_head *list)
 638 {
 639         struct tipc_msg *msg = buf_msg(skb_peek(list));
 640         unsigned int maxwin = link->window;
 641         unsigned int i, imp = msg_importance(msg);
 642         uint mtu = link->mtu;
 643         u16 ack = mod(link->rcv_nxt - 1);
 644         u16 seqno = link->snd_nxt;
 645         u16 bc_last_in = link->owner->bclink.last_in;
 646         struct tipc_media_addr *addr = link->media_addr;
 647         struct sk_buff_head *transmq = &link->transmq;
 648         struct sk_buff_head *backlogq = &link->backlogq;
 649         struct sk_buff *skb, *bskb;
 650
 651         /* Match msg importance against this and all higher backlog limits: */
 652         for (i = imp; i <= TIPC_SYSTEM_IMPORTANCE; i++) {
 653                 if (unlikely(link->backlog[i].len >= link->backlog[i].limit))
 654                         return link_schedule_user(link, list);
 655         }
 656         if (unlikely(msg_size(msg) > mtu))
 657                 return -EMSGSIZE;
 658
 659         /* Prepare each packet for sending, and add to relevant queue: */
 660         while (skb_queue_len(list)) {
 661                 skb = skb_peek(list);
 662                 msg = buf_msg(skb);
 663                 msg_set_seqno(msg, seqno);
 664                 msg_set_ack(msg, ack);
 665                 msg_set_bcast_ack(msg, bc_last_in);
 666
 667                 if (likely(skb_queue_len(transmq) < maxwin)) {
 668                         __skb_dequeue(list);
 669                         __skb_queue_tail(transmq, skb);
 670                         tipc_bearer_send(net, link->bearer_id, skb, addr);
 671                         link->rcv_unacked = 0;
 672                         seqno++;
 673                         continue;
 674                 }
 675                 if (tipc_msg_bundle(skb_peek_tail(backlogq), msg, mtu)) {
 676                         kfree_skb(__skb_dequeue(list));
 677                         link->stats.sent_bundled++;
 678                         continue;
 679                 }
 680                 if (tipc_msg_make_bundle(&bskb, msg, mtu, link->addr)) {
 681                         kfree_skb(__skb_dequeue(list));
 682                         __skb_queue_tail(backlogq, bskb);
 683                         link->backlog[msg_importance(buf_msg(bskb))].len++;
 684                         link->stats.sent_bundled++;
 685                         link->stats.sent_bundles++;
 686                         continue;
 687                 }
 688                 link->backlog[imp].len += skb_queue_len(list);
 689                 skb_queue_splice_tail_init(list, backlogq);
 690         }
 691         link->snd_nxt = seqno;
 692         return 0;
 693 }
 694
 695 /**
 696  * tipc_link_xmit(): enqueue buffer list according to queue situation
 697  * @link: link to use
 698  * @list: chain of buffers containing message
 699  * @xmitq: returned list of packets to be sent by caller
 700  *
 701  * Consumes the buffer chain, except when returning -ELINKCONG,
 702  * since the caller then may want to make more send attempts.
 703  * Returns 0 if success, or errno: -ELINKCONG, -EMSGSIZE or -ENOBUFS
 704  * Messages at TIPC_SYSTEM_IMPORTANCE are always accepted
 705  */
 706 int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *list,
 707                    struct sk_buff_head *xmitq)
 708 {
 709         struct tipc_msg *hdr = buf_msg(skb_peek(list));
 710         unsigned int maxwin = l->window;
 711         unsigned int i, imp = msg_importance(hdr);
 712         unsigned int mtu = l->mtu;
 713         u16 ack = l->rcv_nxt - 1;
 714         u16 seqno = l->snd_nxt;
 715         u16 bc_last_in = l->owner->bclink.last_in;
 716         struct sk_buff_head *transmq = &l->transmq;
 717         struct sk_buff_head *backlogq = &l->backlogq;
 718         struct sk_buff *skb, *_skb, *bskb;
 719
 720         /* Match msg importance against this and all higher backlog limits: */
 721         for (i = imp; i <= TIPC_SYSTEM_IMPORTANCE; i++) {
 722                 if (unlikely(l->backlog[i].len >= l->backlog[i].limit))
 723                         return link_schedule_user(l, list);
 724         }
 725         if (unlikely(msg_size(hdr) > mtu))
 726                 return -EMSGSIZE;
 727
 728         /* Prepare each packet for sending, and add to relevant queue: */
 729         while (skb_queue_len(list)) {
 730                 skb = skb_peek(list);
 731                 hdr = buf_msg(skb);
 732                 msg_set_seqno(hdr, seqno);
 733                 msg_set_ack(hdr, ack);
 734                 msg_set_bcast_ack(hdr, bc_last_in);
 735
 736                 if (likely(skb_queue_len(transmq) < maxwin)) {
 737                         _skb = skb_clone(skb, GFP_ATOMIC);
 738                         if (!_skb)
 739                                 return -ENOBUFS;
 740                         __skb_dequeue(list);
 741                         __skb_queue_tail(transmq, skb);
 742                         __skb_queue_tail(xmitq, _skb);
 743                         l->rcv_unacked = 0;
 744                         seqno++;
 745                         continue;
 746                 }
 747                 if (tipc_msg_bundle(skb_peek_tail(backlogq), hdr, mtu)) {
 748                         kfree_skb(__skb_dequeue(list));
 749                         l->stats.sent_bundled++;
 750                         continue;
 751                 }
 752                 if (tipc_msg_make_bundle(&bskb, hdr, mtu, l->addr)) {
 753                         kfree_skb(__skb_dequeue(list));
 754                         __skb_queue_tail(backlogq, bskb);
 755                         l->backlog[msg_importance(buf_msg(bskb))].len++;
 756                         l->stats.sent_bundled++;
 757                         l->stats.sent_bundles++;
 758                         continue;
 759                 }
 760                 l->backlog[imp].len += skb_queue_len(list);
 761                 skb_queue_splice_tail_init(list, backlogq);
 762         }
 763         l->snd_nxt = seqno;
 764         return 0;
 765 }
 766
 767 /*
 768  * tipc_link_sync_rcv - synchronize broadcast link endpoints.
 769  * Receive the sequence number where we should start receiving and
 770  * acking broadcast packets from a newly added peer node, and open
 771  * up for reception of such packets.
 772  *
 773  * Called with node locked
 774  */
 775 static void tipc_link_sync_rcv(struct tipc_node *n, struct sk_buff *buf)
 776 {
 777         struct tipc_msg *msg = buf_msg(buf);
 778
 779         n->bclink.last_sent = n->bclink.last_in = msg_last_bcast(msg);
 780         n->bclink.recv_permitted = true;
 781         kfree_skb(buf);
 782 }
 783
 784 /*
 785  * tipc_link_push_packets - push unsent packets to bearer
 786  *
 787  * Push out the unsent messages of a link where congestion
 788  * has abated. Node is locked.
 789  *
 790  * Called with node locked
 791  */
 792 void tipc_link_push_packets(struct tipc_link *link)
 793 {
 794         struct sk_buff *skb;
 795         struct tipc_msg *msg;
 796         u16 seqno = link->snd_nxt;
 797         u16 ack = mod(link->rcv_nxt - 1);
 798
 799         while (skb_queue_len(&link->transmq) < link->window) {
 800                 skb = __skb_dequeue(&link->backlogq);
 801                 if (!skb)
 802                         break;
 803                 msg = buf_msg(skb);
 804                 link->backlog[msg_importance(msg)].len--;
 805                 msg_set_ack(msg, ack);
 806                 msg_set_seqno(msg, seqno);
 807                 seqno = mod(seqno + 1);
 808                 msg_set_bcast_ack(msg, link->owner->bclink.last_in);
 809                 link->rcv_unacked = 0;
 810                 __skb_queue_tail(&link->transmq, skb);
 811                 tipc_bearer_send(link->owner->net, link->bearer_id,
 812                                  skb, link->media_addr);
 813         }
 814         link->snd_nxt = seqno;
 815 }
 816
 817 void tipc_link_advance_backlog(struct tipc_link *l, struct sk_buff_head *xmitq)
 818 {
 819         struct sk_buff *skb, *_skb;
 820         struct tipc_msg *hdr;
 821         u16 seqno = l->snd_nxt;
 822         u16 ack = l->rcv_nxt - 1;
 823
 824         while (skb_queue_len(&l->transmq) < l->window) {
 825                 skb = skb_peek(&l->backlogq);
 826                 if (!skb)
 827                         break;
 828                 _skb = skb_clone(skb, GFP_ATOMIC);
 829                 if (!_skb)
 830                         break;
 831                 __skb_dequeue(&l->backlogq);
 832                 hdr = buf_msg(skb);
 833                 l->backlog[msg_importance(hdr)].len--;
 834                 __skb_queue_tail(&l->transmq, skb);
 835                 __skb_queue_tail(xmitq, _skb);
 836                 msg_set_ack(hdr, ack);
 837                 msg_set_seqno(hdr, seqno);
 838                 msg_set_bcast_ack(hdr, l->owner->bclink.last_in);
 839                 l->rcv_unacked = 0;
 840                 seqno++;
 841         }
 842         l->snd_nxt = seqno;
 843 }
 844
 845 static void link_retransmit_failure(struct tipc_link *l_ptr,
 846                                     struct sk_buff *buf)
 847 {
 848         struct tipc_msg *msg = buf_msg(buf);
 849         struct net *net = l_ptr->owner->net;
 850
 851         pr_warn("Retransmission failure on link <%s>\n", l_ptr->name);
 852
 853         if (l_ptr->addr) {
 854                 /* Handle failure on standard link */
 855                 link_print(l_ptr, "Resetting link ");
 856                 pr_info("Failed msg: usr %u, typ %u, len %u, err %u\n",
 857                         msg_user(msg), msg_type(msg), msg_size(msg),
 858                         msg_errcode(msg));
 859                 pr_info("sqno %u, prev: %x, src: %x\n",
 860                         msg_seqno(msg), msg_prevnode(msg), msg_orignode(msg));
 861         } else {
 862                 /* Handle failure on broadcast link */
 863                 struct tipc_node *n_ptr;
 864                 char addr_string[16];
 865
 866                 pr_info("Msg seq number: %u,  ", msg_seqno(msg));
 867                 pr_cont("Outstanding acks: %lu\n",
 868                         (unsigned long) TIPC_SKB_CB(buf)->handle);
 869
 870                 n_ptr = tipc_bclink_retransmit_to(net);
 871
 872                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 873                 pr_info("Broadcast link info for %s\n", addr_string);
 874                 pr_info("Reception permitted: %d,  Acked: %u\n",
 875                         n_ptr->bclink.recv_permitted,
 876                         n_ptr->bclink.acked);
 877                 pr_info("Last in: %u,  Oos state: %u,  Last sent: %u\n",
 878                         n_ptr->bclink.last_in,
 879                         n_ptr->bclink.oos_state,
 880                         n_ptr->bclink.last_sent);
 881
 882                 n_ptr->action_flags |= TIPC_BCAST_RESET;
 883                 l_ptr->stale_count = 0;
 884         }
 885 }
 886
 887 void tipc_link_retransmit(struct tipc_link *l_ptr, struct sk_buff *skb,
 888                           u32 retransmits)
 889 {
 890         struct tipc_msg *msg;
 891
 892         if (!skb)
 893                 return;
 894
 895         msg = buf_msg(skb);
 896
 897         /* Detect repeated retransmit failures */
 898         if (l_ptr->last_retransm == msg_seqno(msg)) {
 899                 if (++l_ptr->stale_count > 100) {
 900                         link_retransmit_failure(l_ptr, skb);
 901                         return;
 902                 }
 903         } else {
 904                 l_ptr->last_retransm = msg_seqno(msg);
 905                 l_ptr->stale_count = 1;
 906         }
 907
 908         skb_queue_walk_from(&l_ptr->transmq, skb) {
 909                 if (!retransmits)
 910                         break;
 911                 msg = buf_msg(skb);
 912                 msg_set_ack(msg, mod(l_ptr->rcv_nxt - 1));
 913                 msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
 914                 tipc_bearer_send(l_ptr->owner->net, l_ptr->bearer_id, skb,
 915                                  l_ptr->media_addr);
 916                 retransmits--;
 917                 l_ptr->stats.retransmitted++;
 918         }
 919 }
 920
 921 static int tipc_link_retransm(struct tipc_link *l, int retransm,
 922                               struct sk_buff_head *xmitq)
 923 {
 924         struct sk_buff *_skb, *skb = skb_peek(&l->transmq);
 925         struct tipc_msg *hdr;
 926
 927         if (!skb)
 928                 return 0;
 929
 930         /* Detect repeated retransmit failures on same packet */
 931         if (likely(l->last_retransm != buf_seqno(skb))) {
 932                 l->last_retransm = buf_seqno(skb);
 933                 l->stale_count = 1;
 934         } else if (++l->stale_count > 100) {
 935                 link_retransmit_failure(l, skb);
 936                 return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
 937         }
 938         skb_queue_walk(&l->transmq, skb) {
 939                 if (!retransm)
 940                         return 0;
 941                 hdr = buf_msg(skb);
 942                 _skb = __pskb_copy(skb, MIN_H_SIZE, GFP_ATOMIC);
 943                 if (!_skb)
 944                         return 0;
 945                 hdr = buf_msg(_skb);
 946                 msg_set_ack(hdr, l->rcv_nxt - 1);
 947                 msg_set_bcast_ack(hdr, l->owner->bclink.last_in);
 948                 _skb->priority = TC_PRIO_CONTROL;
 949                 __skb_queue_tail(xmitq, _skb);
 950                 retransm--;
 951                 l->stats.retransmitted++;
 952         }
 953         return 0;
 954 }
 955
 956 /* tipc_data_input - deliver data and name distr msgs to upper layer
 957  *
 958  * Consumes buffer if message is of right type
 959  * Node lock must be held
 960  */
 961 static bool tipc_data_input(struct tipc_link *link, struct sk_buff *skb,
 962                             struct sk_buff_head *inputq)
 963 {
 964         struct tipc_node *node = link->owner;
 965
 966         switch (msg_user(buf_msg(skb))) {
 967         case TIPC_LOW_IMPORTANCE:
 968         case TIPC_MEDIUM_IMPORTANCE:
 969         case TIPC_HIGH_IMPORTANCE:
 970         case TIPC_CRITICAL_IMPORTANCE:
 971         case CONN_MANAGER:
 972                 skb_queue_tail(inputq, skb);
 973                 return true;
 974         case NAME_DISTRIBUTOR:
 975                 node->bclink.recv_permitted = true;
 976                 skb_queue_tail(link->namedq, skb);
 977                 return true;
 978         case MSG_BUNDLER:
 979         case TUNNEL_PROTOCOL:
 980         case MSG_FRAGMENTER:
 981         case BCAST_PROTOCOL:
 982                 return false;
 983         default:
 984                 pr_warn("Dropping received illegal msg type\n");
 985                 kfree_skb(skb);
 986                 return false;
 987         };
 988 }
 989
 990 /* tipc_link_input - process packet that has passed link protocol check
 991  *
 992  * Consumes buffer
 993  */
 994 static int tipc_link_input(struct tipc_link *l, struct sk_buff *skb,
 995                            struct sk_buff_head *inputq)
 996 {
 997         struct tipc_node *node = l->owner;
 998         struct tipc_msg *hdr = buf_msg(skb);
 999         struct sk_buff **reasm_skb = &l->reasm_buf;
1000         struct sk_buff *iskb;
1001         struct sk_buff_head tmpq;
1002         int usr = msg_user(hdr);
1003         int rc = 0;
1004         int pos = 0;
1005         int ipos = 0;
1006
1007         if (unlikely(usr == TUNNEL_PROTOCOL)) {
1008                 if (msg_type(hdr) == SYNCH_MSG) {
1009                         __skb_queue_purge(&l->deferdq);
1010                         goto drop;
1011                 }
1012                 if (!tipc_msg_extract(skb, &iskb, &ipos))
1013                         return rc;
1014                 kfree_skb(skb);
1015                 skb = iskb;
1016                 hdr = buf_msg(skb);
1017                 if (less(msg_seqno(hdr), l->drop_point))
1018                         goto drop;
1019                 if (tipc_data_input(l, skb, inputq))
1020                         return rc;
1021                 usr = msg_user(hdr);
1022                 reasm_skb = &l->failover_reasm_skb;
1023         }
1024
1025         if (usr == MSG_BUNDLER) {
1026                 skb_queue_head_init(&tmpq);
1027                 l->stats.recv_bundles++;
1028                 l->stats.recv_bundled += msg_msgcnt(hdr);
1029                 while (tipc_msg_extract(skb, &iskb, &pos))
1030                         tipc_data_input(l, iskb, &tmpq);
1031                 tipc_skb_queue_splice_tail(&tmpq, inputq);
1032                 return 0;
1033         } else if (usr == MSG_FRAGMENTER) {
1034                 l->stats.recv_fragments++;
1035                 if (tipc_buf_append(reasm_skb, &skb)) {
1036                         l->stats.recv_fragmented++;
1037                         tipc_data_input(l, skb, inputq);
1038                 } else if (!*reasm_skb) {
1039                         return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1040                 }
1041                 return 0;
1042         } else if (usr == BCAST_PROTOCOL) {
1043                 tipc_link_sync_rcv(node, skb);
1044                 return 0;
1045         }
1046 drop:
1047         kfree_skb(skb);
1048         return 0;
1049 }
1050
1051 static bool tipc_link_release_pkts(struct tipc_link *l, u16 acked)
1052 {
1053         bool released = false;
1054         struct sk_buff *skb, *tmp;
1055
1056         skb_queue_walk_safe(&l->transmq, skb, tmp) {
1057                 if (more(buf_seqno(skb), acked))
1058                         break;
1059                 __skb_unlink(skb, &l->transmq);
1060                 kfree_skb(skb);
1061                 released = true;
1062         }
1063         return released;
1064 }
1065
1066 /* tipc_link_build_ack_msg: prepare link acknowledge message for transmission
1067  */
1068 void tipc_link_build_ack_msg(struct tipc_link *l, struct sk_buff_head *xmitq)
1069 {
1070         l->rcv_unacked = 0;
1071         l->stats.sent_acks++;
1072         tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, 0, xmitq);
1073 }
1074
1075 /* tipc_link_build_reset_msg: prepare link RESET or ACTIVATE message
1076  */
1077 void tipc_link_build_reset_msg(struct tipc_link *l, struct sk_buff_head *xmitq)
1078 {
1079         int mtyp = RESET_MSG;
1080
1081         if (l->state == LINK_ESTABLISHING)
1082                 mtyp = ACTIVATE_MSG;
1083
1084         tipc_link_build_proto_msg(l, mtyp, 0, 0, 0, 0, xmitq);
1085 }
1086
1087 /* tipc_link_build_nack_msg: prepare link nack message for transmission
1088  */
1089 static void tipc_link_build_nack_msg(struct tipc_link *l,
1090                                      struct sk_buff_head *xmitq)
1091 {
1092         u32 def_cnt = ++l->stats.deferred_recv;
1093
1094         if ((skb_queue_len(&l->deferdq) == 1) || !(def_cnt % TIPC_NACK_INTV))
1095                 tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, 0, xmitq);
1096 }
1097
1098 /* tipc_link_rcv - process TIPC packets/messages arriving from off-node
1099  * @l: the link that should handle the message
1100  * @skb: TIPC packet
1101  * @xmitq: queue to place packets to be sent after this call
1102  */
1103 int tipc_link_rcv(struct tipc_link *l, struct sk_buff *skb,
1104                   struct sk_buff_head *xmitq)
1105 {
1106         struct sk_buff_head *defq = &l->deferdq;
1107         struct tipc_msg *hdr;
1108         u16 seqno, rcv_nxt, win_lim;
1109         int rc = 0;
1110
1111         do {
1112                 hdr = buf_msg(skb);
1113                 seqno = msg_seqno(hdr);
1114                 rcv_nxt = l->rcv_nxt;
1115                 win_lim = rcv_nxt + TIPC_MAX_LINK_WIN;
1116
1117                 /* Verify and update link state */
1118                 if (unlikely(msg_user(hdr) == LINK_PROTOCOL))
1119                         return tipc_link_proto_rcv(l, skb, xmitq);
1120
1121                 if (unlikely(!link_is_up(l))) {
1122                         if (l->state == LINK_ESTABLISHING)
1123                                 rc = TIPC_LINK_UP_EVT;
1124                         goto drop;
1125                 }
1126
1127                 /* Don't send probe at next timeout expiration */
1128                 l->silent_intv_cnt = 0;
1129
1130                 /* Drop if outside receive window */
1131                 if (unlikely(less(seqno, rcv_nxt) || more(seqno, win_lim))) {
1132                         l->stats.duplicates++;
1133                         goto drop;
1134                 }
1135
1136                 /* Forward queues and wake up waiting users */
1137                 if (likely(tipc_link_release_pkts(l, msg_ack(hdr)))) {
1138                         tipc_link_advance_backlog(l, xmitq);
1139                         if (unlikely(!skb_queue_empty(&l->wakeupq)))
1140                                 link_prepare_wakeup(l);
1141                 }
1142
1143                 /* Defer delivery if sequence gap */
1144                 if (unlikely(seqno != rcv_nxt)) {
1145                         __tipc_skb_queue_sorted(defq, seqno, skb);
1146                         tipc_link_build_nack_msg(l, xmitq);
1147                         break;
1148                 }
1149
1150                 /* Deliver packet */
1151                 l->rcv_nxt++;
1152                 l->stats.recv_info++;
1153                 if (!tipc_data_input(l, skb, l->inputq))
1154                         rc = tipc_link_input(l, skb, l->inputq);
1155                 if (unlikely(rc))
1156                         break;
1157                 if (unlikely(++l->rcv_unacked >= TIPC_MIN_LINK_WIN))
1158                         tipc_link_build_ack_msg(l, xmitq);
1159
1160         } while ((skb = __skb_dequeue(defq)));
1161
1162         return rc;
1163 drop:
1164         kfree_skb(skb);
1165         return rc;
1166 }
1167
1168 /**
1169  * tipc_link_defer_pkt - Add out-of-sequence message to deferred reception queue
1170  *
1171  * Returns increase in queue length (i.e. 0 or 1)
1172  */
1173 u32 tipc_link_defer_pkt(struct sk_buff_head *list, struct sk_buff *skb)
1174 {
1175         struct sk_buff *skb1;
1176         u16 seq_no = buf_seqno(skb);
1177
1178         /* Empty queue ? */
1179         if (skb_queue_empty(list)) {
1180                 __skb_queue_tail(list, skb);
1181                 return 1;
1182         }
1183
1184         /* Last ? */
1185         if (less(buf_seqno(skb_peek_tail(list)), seq_no)) {
1186                 __skb_queue_tail(list, skb);
1187                 return 1;
1188         }
1189
1190         /* Locate insertion point in queue, then insert; discard if duplicate */
1191         skb_queue_walk(list, skb1) {
1192                 u16 curr_seqno = buf_seqno(skb1);
1193
1194                 if (seq_no == curr_seqno) {
1195                         kfree_skb(skb);
1196                         return 0;
1197                 }
1198
1199                 if (less(seq_no, curr_seqno))
1200                         break;
1201         }
1202
1203         __skb_queue_before(list, skb1, skb);
1204         return 1;
1205 }
1206
1207 /*
1208  * Send protocol message to the other endpoint.
1209  */
1210 void tipc_link_proto_xmit(struct tipc_link *l, u32 msg_typ, int probe_msg,
1211                           u32 gap, u32 tolerance, u32 priority)
1212 {
1213         struct sk_buff *skb = NULL;
1214         struct sk_buff_head xmitq;
1215
1216         __skb_queue_head_init(&xmitq);
1217         tipc_link_build_proto_msg(l, msg_typ, probe_msg, gap,
1218                                   tolerance, priority, &xmitq);
1219         skb = __skb_dequeue(&xmitq);
1220         if (!skb)
1221                 return;
1222         tipc_bearer_send(l->owner->net, l->bearer_id, skb, l->media_addr);
1223         l->rcv_unacked = 0;
1224         kfree_skb(skb);
1225 }
1226
1227 /* tipc_link_build_proto_msg: prepare link protocol message for transmission
1228  */
1229 static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
1230                                       u16 rcvgap, int tolerance, int priority,
1231                                       struct sk_buff_head *xmitq)
1232 {
1233         struct sk_buff *skb = NULL;
1234         struct tipc_msg *hdr = l->pmsg;
1235         u16 snd_nxt = l->snd_nxt;
1236         u16 rcv_nxt = l->rcv_nxt;
1237         u16 rcv_last = rcv_nxt - 1;
1238         int node_up = l->owner->bclink.recv_permitted;
1239
1240         /* Don't send protocol message during reset or link failover */
1241         if (tipc_link_is_blocked(l))
1242                 return;
1243
1244         msg_set_type(hdr, mtyp);
1245         msg_set_net_plane(hdr, l->net_plane);
1246         msg_set_bcast_ack(hdr, l->owner->bclink.last_in);
1247         msg_set_last_bcast(hdr, tipc_bclink_get_last_sent(l->owner->net));
1248         msg_set_link_tolerance(hdr, tolerance);
1249         msg_set_linkprio(hdr, priority);
1250         msg_set_redundant_link(hdr, node_up);
1251         msg_set_seq_gap(hdr, 0);
1252
1253         /* Compatibility: created msg must not be in sequence with pkt flow */
1254         msg_set_seqno(hdr, snd_nxt + U16_MAX / 2);
1255
1256         if (mtyp == STATE_MSG) {
1257                 if (!tipc_link_is_up(l))
1258                         return;
1259                 msg_set_next_sent(hdr, snd_nxt);
1260
1261                 /* Override rcvgap if there are packets in deferred queue */
1262                 if (!skb_queue_empty(&l->deferdq))
1263                         rcvgap = buf_seqno(skb_peek(&l->deferdq)) - rcv_nxt;
1264                 if (rcvgap) {
1265                         msg_set_seq_gap(hdr, rcvgap);
1266                         l->stats.sent_nacks++;
1267                 }
1268                 msg_set_ack(hdr, rcv_last);
1269                 msg_set_probe(hdr, probe);
1270                 if (probe)
1271                         l->stats.sent_probes++;
1272                 l->stats.sent_states++;
1273         } else {
1274                 /* RESET_MSG or ACTIVATE_MSG */
1275                 msg_set_max_pkt(hdr, l->advertised_mtu);
1276                 msg_set_ack(hdr, l->rcv_nxt - 1);
1277                 msg_set_next_sent(hdr, 1);
1278         }
1279         skb = tipc_buf_acquire(msg_size(hdr));
1280         if (!skb)
1281                 return;
1282         skb_copy_to_linear_data(skb, hdr, msg_size(hdr));
1283         skb->priority = TC_PRIO_CONTROL;
1284         __skb_queue_tail(xmitq, skb);
1285 }
1286
1287 /* tipc_link_tnl_prepare(): prepare and return a list of tunnel packets
1288  * with contents of the link's transmit and backlog queues.
1289  */
1290 void tipc_link_tnl_prepare(struct tipc_link *l, struct tipc_link *tnl,
1291                            int mtyp, struct sk_buff_head *xmitq)
1292 {
1293         struct sk_buff *skb, *tnlskb;
1294         struct tipc_msg *hdr, tnlhdr;
1295         struct sk_buff_head *queue = &l->transmq;
1296         struct sk_buff_head tmpxq, tnlq;
1297         u16 pktlen, pktcnt, seqno = l->snd_nxt;
1298
1299         if (!tnl)
1300                 return;
1301
1302         skb_queue_head_init(&tnlq);
1303         skb_queue_head_init(&tmpxq);
1304
1305         /* At least one packet required for safe algorithm => add dummy */
1306         skb = tipc_msg_create(TIPC_LOW_IMPORTANCE, TIPC_DIRECT_MSG,
1307                               BASIC_H_SIZE, 0, l->addr, link_own_addr(l),
1308                               0, 0, TIPC_ERR_NO_PORT);
1309         if (!skb) {
1310                 pr_warn("%sunable to create tunnel packet\n", link_co_err);
1311                 return;
1312         }
1313         skb_queue_tail(&tnlq, skb);
1314         tipc_link_xmit(l, &tnlq, &tmpxq);
1315         __skb_queue_purge(&tmpxq);
1316
1317         /* Initialize reusable tunnel packet header */
1318         tipc_msg_init(link_own_addr(l), &tnlhdr, TUNNEL_PROTOCOL,
1319                       mtyp, INT_H_SIZE, l->addr);
1320         pktcnt = skb_queue_len(&l->transmq) + skb_queue_len(&l->backlogq);
1321         msg_set_msgcnt(&tnlhdr, pktcnt);
1322         msg_set_bearer_id(&tnlhdr, l->peer_bearer_id);
1323 tnl:
1324         /* Wrap each packet into a tunnel packet */
1325         skb_queue_walk(queue, skb) {
1326                 hdr = buf_msg(skb);
1327                 if (queue == &l->backlogq)
1328                         msg_set_seqno(hdr, seqno++);
1329                 pktlen = msg_size(hdr);
1330                 msg_set_size(&tnlhdr, pktlen + INT_H_SIZE);
1331                 tnlskb = tipc_buf_acquire(pktlen + INT_H_SIZE);
1332                 if (!tnlskb) {
1333                         pr_warn("%sunable to send packet\n", link_co_err);
1334                         return;
1335                 }
1336                 skb_copy_to_linear_data(tnlskb, &tnlhdr, INT_H_SIZE);
1337                 skb_copy_to_linear_data_offset(tnlskb, INT_H_SIZE, hdr, pktlen);
1338                 __skb_queue_tail(&tnlq, tnlskb);
1339         }
1340         if (queue != &l->backlogq) {
1341                 queue = &l->backlogq;
1342                 goto tnl;
1343         }
1344
1345         tipc_link_xmit(tnl, &tnlq, xmitq);
1346
1347         if (mtyp == FAILOVER_MSG) {
1348                 tnl->drop_point = l->rcv_nxt;
1349                 tnl->failover_reasm_skb = l->reasm_buf;
1350                 l->reasm_buf = NULL;
1351         }
1352 }
1353
1354 /* tipc_link_proto_rcv(): receive link level protocol message :
1355  * Note that network plane id propagates through the network, and may
1356  * change at any time. The node with lowest numerical id determines
1357  * network plane
1358  */
1359 static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
1360                                struct sk_buff_head *xmitq)
1361 {
1362         struct tipc_msg *hdr = buf_msg(skb);
1363         u16 rcvgap = 0;
1364         u16 nacked_gap = msg_seq_gap(hdr);
1365         u16 peers_snd_nxt =  msg_next_sent(hdr);
1366         u16 peers_tol = msg_link_tolerance(hdr);
1367         u16 peers_prio = msg_linkprio(hdr);
1368         u16 rcv_nxt = l->rcv_nxt;
1369         int mtyp = msg_type(hdr);
1370         char *if_name;
1371         int rc = 0;
1372
1373         if (tipc_link_is_blocked(l))
1374                 goto exit;
1375
1376         if (link_own_addr(l) > msg_prevnode(hdr))
1377                 l->net_plane = msg_net_plane(hdr);
1378
1379         switch (mtyp) {
1380         case RESET_MSG:
1381
1382                 /* Ignore duplicate RESET with old session number */
1383                 if ((less_eq(msg_session(hdr), l->peer_session)) &&
1384                     (l->peer_session != WILDCARD_SESSION))
1385                         break;
1386                 /* fall thru' */
1387
1388         case ACTIVATE_MSG:
1389
1390                 /* Complete own link name with peer's interface name */
1391                 if_name =  strrchr(l->name, ':') + 1;
1392                 if (sizeof(l->name) - (if_name - l->name) <= TIPC_MAX_IF_NAME)
1393                         break;
1394                 if (msg_data_sz(hdr) < TIPC_MAX_IF_NAME)
1395                         break;
1396                 strncpy(if_name, msg_data(hdr), TIPC_MAX_IF_NAME);
1397
1398                 /* Update own tolerance if peer indicates a non-zero value */
1399                 if (in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL))
1400                         l->tolerance = peers_tol;
1401
1402                 /* Update own priority if peer's priority is higher */
1403                 if (in_range(peers_prio, l->priority + 1, TIPC_MAX_LINK_PRI))
1404                         l->priority = peers_prio;
1405
1406                 /* ACTIVATE_MSG serves as PEER_RESET if link is already down */
1407                 if ((mtyp == RESET_MSG) || !link_is_up(l))
1408                         rc = tipc_link_fsm_evt(l, LINK_PEER_RESET_EVT);
1409
1410                 /* ACTIVATE_MSG takes up link if it was already locally reset */
1411                 if ((mtyp == ACTIVATE_MSG) && (l->state == LINK_ESTABLISHING))
1412                         rc = TIPC_LINK_UP_EVT;
1413
1414                 l->peer_session = msg_session(hdr);
1415                 l->peer_bearer_id = msg_bearer_id(hdr);
1416                 if (l->mtu > msg_max_pkt(hdr))
1417                         l->mtu = msg_max_pkt(hdr);
1418                 break;
1419
1420         case STATE_MSG:
1421
1422                 /* Update own tolerance if peer indicates a non-zero value */
1423                 if (in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL))
1424                         l->tolerance = peers_tol;
1425
1426                 l->silent_intv_cnt = 0;
1427                 l->stats.recv_states++;
1428                 if (msg_probe(hdr))
1429                         l->stats.recv_probes++;
1430
1431                 if (!link_is_up(l)) {
1432                         if (l->state == LINK_ESTABLISHING)
1433                                 rc = TIPC_LINK_UP_EVT;
1434                         break;
1435                 }
1436
1437                 /* Send NACK if peer has sent pkts we haven't received yet */
1438                 if (more(peers_snd_nxt, rcv_nxt) && !tipc_link_is_synching(l))
1439                         rcvgap = peers_snd_nxt - l->rcv_nxt;
1440                 if (rcvgap || (msg_probe(hdr)))
1441                         tipc_link_build_proto_msg(l, STATE_MSG, 0, rcvgap,
1442                                                   0, 0, xmitq);
1443                 tipc_link_release_pkts(l, msg_ack(hdr));
1444
1445                 /* If NACK, retransmit will now start at right position */
1446                 if (nacked_gap) {
1447                         rc = tipc_link_retransm(l, nacked_gap, xmitq);
1448                         l->stats.recv_nacks++;
1449                 }
1450
1451                 tipc_link_advance_backlog(l, xmitq);
1452                 if (unlikely(!skb_queue_empty(&l->wakeupq)))
1453                         link_prepare_wakeup(l);
1454         }
1455 exit:
1456         kfree_skb(skb);
1457         return rc;
1458 }
1459
1460 void tipc_link_set_queue_limits(struct tipc_link *l, u32 win)
1461 {
1462         int max_bulk = TIPC_MAX_PUBLICATIONS / (l->mtu / ITEM_SIZE);
1463
1464         l->window = win;
1465         l->backlog[TIPC_LOW_IMPORTANCE].limit      = win / 2;
1466         l->backlog[TIPC_MEDIUM_IMPORTANCE].limit   = win;
1467         l->backlog[TIPC_HIGH_IMPORTANCE].limit     = win / 2 * 3;
1468         l->backlog[TIPC_CRITICAL_IMPORTANCE].limit = win * 2;
1469         l->backlog[TIPC_SYSTEM_IMPORTANCE].limit   = max_bulk;
1470 }
1471
1472 /* tipc_link_find_owner - locate owner node of link by link's name
1473  * @net: the applicable net namespace
1474  * @name: pointer to link name string
1475  * @bearer_id: pointer to index in 'node->links' array where the link was found.
1476  *
1477  * Returns pointer to node owning the link, or 0 if no matching link is found.
1478  */
1479 static struct tipc_node *tipc_link_find_owner(struct net *net,
1480                                               const char *link_name,
1481                                               unsigned int *bearer_id)
1482 {
1483         struct tipc_net *tn = net_generic(net, tipc_net_id);
1484         struct tipc_link *l_ptr;
1485         struct tipc_node *n_ptr;
1486         struct tipc_node *found_node = NULL;
1487         int i;
1488
1489         *bearer_id = 0;
1490         rcu_read_lock();
1491         list_for_each_entry_rcu(n_ptr, &tn->node_list, list) {
1492                 tipc_node_lock(n_ptr);
1493                 for (i = 0; i < MAX_BEARERS; i++) {
1494                         l_ptr = n_ptr->links[i].link;
1495                         if (l_ptr && !strcmp(l_ptr->name, link_name)) {
1496                                 *bearer_id = i;
1497                                 found_node = n_ptr;
1498                                 break;
1499                         }
1500                 }
1501                 tipc_node_unlock(n_ptr);
1502                 if (found_node)
1503                         break;
1504         }
1505         rcu_read_unlock();
1506
1507         return found_node;
1508 }
1509
1510 /**
1511  * link_reset_statistics - reset link statistics
1512  * @l_ptr: pointer to link
1513  */
1514 static void link_reset_statistics(struct tipc_link *l_ptr)
1515 {
1516         memset(&l_ptr->stats, 0, sizeof(l_ptr->stats));
1517         l_ptr->stats.sent_info = l_ptr->snd_nxt;
1518         l_ptr->stats.recv_info = l_ptr->rcv_nxt;
1519 }
1520
1521 static void link_print(struct tipc_link *l, const char *str)
1522 {
1523         struct sk_buff *hskb = skb_peek(&l->transmq);
1524         u16 head = hskb ? msg_seqno(buf_msg(hskb)) : l->snd_nxt;
1525         u16 tail = l->snd_nxt - 1;
1526
1527         pr_info("%s Link <%s> state %x\n", str, l->name, l->state);
1528         pr_info("XMTQ: %u [%u-%u], BKLGQ: %u, SNDNX: %u, RCVNX: %u\n",
1529                 skb_queue_len(&l->transmq), head, tail,
1530                 skb_queue_len(&l->backlogq), l->snd_nxt, l->rcv_nxt);
1531 }
1532
1533 /* Parse and validate nested (link) properties valid for media, bearer and link
1534  */
1535 int tipc_nl_parse_link_prop(struct nlattr *prop, struct nlattr *props[])
1536 {
1537         int err;
1538
1539         err = nla_parse_nested(props, TIPC_NLA_PROP_MAX, prop,
1540                                tipc_nl_prop_policy);
1541         if (err)
1542                 return err;
1543
1544         if (props[TIPC_NLA_PROP_PRIO]) {
1545                 u32 prio;
1546
1547                 prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
1548                 if (prio > TIPC_MAX_LINK_PRI)
1549                         return -EINVAL;
1550         }
1551
1552         if (props[TIPC_NLA_PROP_TOL]) {
1553                 u32 tol;
1554
1555                 tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
1556                 if ((tol < TIPC_MIN_LINK_TOL) || (tol > TIPC_MAX_LINK_TOL))
1557                         return -EINVAL;
1558         }
1559
1560         if (props[TIPC_NLA_PROP_WIN]) {
1561                 u32 win;
1562
1563                 win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
1564                 if ((win < TIPC_MIN_LINK_WIN) || (win > TIPC_MAX_LINK_WIN))
1565                         return -EINVAL;
1566         }
1567
1568         return 0;
1569 }
1570
1571 int tipc_nl_link_set(struct sk_buff *skb, struct genl_info *info)
1572 {
1573         int err;
1574         int res = 0;
1575         int bearer_id;
1576         char *name;
1577         struct tipc_link *link;
1578         struct tipc_node *node;
1579         struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
1580         struct net *net = sock_net(skb->sk);
1581
1582         if (!info->attrs[TIPC_NLA_LINK])
1583                 return -EINVAL;
1584
1585         err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
1586                                info->attrs[TIPC_NLA_LINK],
1587                                tipc_nl_link_policy);
1588         if (err)
1589                 return err;
1590
1591         if (!attrs[TIPC_NLA_LINK_NAME])
1592                 return -EINVAL;
1593
1594         name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
1595
1596         if (strcmp(name, tipc_bclink_name) == 0)
1597                 return tipc_nl_bc_link_set(net, attrs);
1598
1599         node = tipc_link_find_owner(net, name, &bearer_id);
1600         if (!node)
1601                 return -EINVAL;
1602
1603         tipc_node_lock(node);
1604
1605         link = node->links[bearer_id].link;
1606         if (!link) {
1607                 res = -EINVAL;
1608                 goto out;
1609         }
1610
1611         if (attrs[TIPC_NLA_LINK_PROP]) {
1612                 struct nlattr *props[TIPC_NLA_PROP_MAX + 1];
1613
1614                 err = tipc_nl_parse_link_prop(attrs[TIPC_NLA_LINK_PROP],
1615                                               props);
1616                 if (err) {
1617                         res = err;
1618                         goto out;
1619                 }
1620
1621                 if (props[TIPC_NLA_PROP_TOL]) {
1622                         u32 tol;
1623
1624                         tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
1625                         link->tolerance = tol;
1626                         tipc_link_proto_xmit(link, STATE_MSG, 0, 0, tol, 0);
1627                 }
1628                 if (props[TIPC_NLA_PROP_PRIO]) {
1629                         u32 prio;
1630
1631                         prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
1632                         link->priority = prio;
1633                         tipc_link_proto_xmit(link, STATE_MSG, 0, 0, 0, prio);
1634                 }
1635                 if (props[TIPC_NLA_PROP_WIN]) {
1636                         u32 win;
1637
1638                         win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
1639                         tipc_link_set_queue_limits(link, win);
1640                 }
1641         }
1642
1643 out:
1644         tipc_node_unlock(node);
1645
1646         return res;
1647 }
1648
1649 static int __tipc_nl_add_stats(struct sk_buff *skb, struct tipc_stats *s)
1650 {
1651         int i;
1652         struct nlattr *stats;
1653
1654         struct nla_map {
1655                 u32 key;
1656                 u32 val;
1657         };
1658
1659         struct nla_map map[] = {
1660                 {TIPC_NLA_STATS_RX_INFO, s->recv_info},
1661                 {TIPC_NLA_STATS_RX_FRAGMENTS, s->recv_fragments},
1662                 {TIPC_NLA_STATS_RX_FRAGMENTED, s->recv_fragmented},
1663                 {TIPC_NLA_STATS_RX_BUNDLES, s->recv_bundles},
1664                 {TIPC_NLA_STATS_RX_BUNDLED, s->recv_bundled},
1665                 {TIPC_NLA_STATS_TX_INFO, s->sent_info},
1666                 {TIPC_NLA_STATS_TX_FRAGMENTS, s->sent_fragments},
1667                 {TIPC_NLA_STATS_TX_FRAGMENTED, s->sent_fragmented},
1668                 {TIPC_NLA_STATS_TX_BUNDLES, s->sent_bundles},
1669                 {TIPC_NLA_STATS_TX_BUNDLED, s->sent_bundled},
1670                 {TIPC_NLA_STATS_MSG_PROF_TOT, (s->msg_length_counts) ?
1671                         s->msg_length_counts : 1},
1672                 {TIPC_NLA_STATS_MSG_LEN_CNT, s->msg_length_counts},
1673                 {TIPC_NLA_STATS_MSG_LEN_TOT, s->msg_lengths_total},
1674                 {TIPC_NLA_STATS_MSG_LEN_P0, s->msg_length_profile[0]},
1675                 {TIPC_NLA_STATS_MSG_LEN_P1, s->msg_length_profile[1]},
1676                 {TIPC_NLA_STATS_MSG_LEN_P2, s->msg_length_profile[2]},
1677                 {TIPC_NLA_STATS_MSG_LEN_P3, s->msg_length_profile[3]},
1678                 {TIPC_NLA_STATS_MSG_LEN_P4, s->msg_length_profile[4]},
1679                 {TIPC_NLA_STATS_MSG_LEN_P5, s->msg_length_profile[5]},
1680                 {TIPC_NLA_STATS_MSG_LEN_P6, s->msg_length_profile[6]},
1681                 {TIPC_NLA_STATS_RX_STATES, s->recv_states},
1682                 {TIPC_NLA_STATS_RX_PROBES, s->recv_probes},
1683                 {TIPC_NLA_STATS_RX_NACKS, s->recv_nacks},
1684                 {TIPC_NLA_STATS_RX_DEFERRED, s->deferred_recv},
1685                 {TIPC_NLA_STATS_TX_STATES, s->sent_states},
1686                 {TIPC_NLA_STATS_TX_PROBES, s->sent_probes},
1687                 {TIPC_NLA_STATS_TX_NACKS, s->sent_nacks},
1688                 {TIPC_NLA_STATS_TX_ACKS, s->sent_acks},
1689                 {TIPC_NLA_STATS_RETRANSMITTED, s->retransmitted},
1690                 {TIPC_NLA_STATS_DUPLICATES, s->duplicates},
1691                 {TIPC_NLA_STATS_LINK_CONGS, s->link_congs},
1692                 {TIPC_NLA_STATS_MAX_QUEUE, s->max_queue_sz},
1693                 {TIPC_NLA_STATS_AVG_QUEUE, s->queue_sz_counts ?
1694                         (s->accu_queue_sz / s->queue_sz_counts) : 0}
1695         };
1696
1697         stats = nla_nest_start(skb, TIPC_NLA_LINK_STATS);
1698         if (!stats)
1699                 return -EMSGSIZE;
1700
1701         for (i = 0; i <  ARRAY_SIZE(map); i++)
1702                 if (nla_put_u32(skb, map[i].key, map[i].val))
1703                         goto msg_full;
1704
1705         nla_nest_end(skb, stats);
1706
1707         return 0;
1708 msg_full:
1709         nla_nest_cancel(skb, stats);
1710
1711         return -EMSGSIZE;
1712 }
1713
1714 /* Caller should hold appropriate locks to protect the link */
1715 static int __tipc_nl_add_link(struct net *net, struct tipc_nl_msg *msg,
1716                               struct tipc_link *link, int nlflags)
1717 {
1718         int err;
1719         void *hdr;
1720         struct nlattr *attrs;
1721         struct nlattr *prop;
1722         struct tipc_net *tn = net_generic(net, tipc_net_id);
1723
1724         hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
1725                           nlflags, TIPC_NL_LINK_GET);
1726         if (!hdr)
1727                 return -EMSGSIZE;
1728
1729         attrs = nla_nest_start(msg->skb, TIPC_NLA_LINK);
1730         if (!attrs)
1731                 goto msg_full;
1732
1733         if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, link->name))
1734                 goto attr_msg_full;
1735         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_DEST,
1736                         tipc_cluster_mask(tn->own_addr)))
1737                 goto attr_msg_full;
1738         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_MTU, link->mtu))
1739                 goto attr_msg_full;
1740         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, link->rcv_nxt))
1741                 goto attr_msg_full;
1742         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, link->snd_nxt))
1743                 goto attr_msg_full;
1744
1745         if (tipc_link_is_up(link))
1746                 if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
1747                         goto attr_msg_full;
1748         if (tipc_link_is_active(link))
1749                 if (nla_put_flag(msg->skb, TIPC_NLA_LINK_ACTIVE))
1750                         goto attr_msg_full;
1751
1752         prop = nla_nest_start(msg->skb, TIPC_NLA_LINK_PROP);
1753         if (!prop)
1754                 goto attr_msg_full;
1755         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
1756                 goto prop_msg_full;
1757         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_TOL, link->tolerance))
1758                 goto prop_msg_full;
1759         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN,
1760                         link->window))
1761                 goto prop_msg_full;
1762         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
1763                 goto prop_msg_full;
1764         nla_nest_end(msg->skb, prop);
1765
1766         err = __tipc_nl_add_stats(msg->skb, &link->stats);
1767         if (err)
1768                 goto attr_msg_full;
1769
1770         nla_nest_end(msg->skb, attrs);
1771         genlmsg_end(msg->skb, hdr);
1772
1773         return 0;
1774
1775 prop_msg_full:
1776         nla_nest_cancel(msg->skb, prop);
1777 attr_msg_full:
1778         nla_nest_cancel(msg->skb, attrs);
1779 msg_full:
1780         genlmsg_cancel(msg->skb, hdr);
1781
1782         return -EMSGSIZE;
1783 }
1784
1785 /* Caller should hold node lock  */
1786 static int __tipc_nl_add_node_links(struct net *net, struct tipc_nl_msg *msg,
1787                                     struct tipc_node *node, u32 *prev_link)
1788 {
1789         u32 i;
1790         int err;
1791
1792         for (i = *prev_link; i < MAX_BEARERS; i++) {
1793                 *prev_link = i;
1794
1795                 if (!node->links[i].link)
1796                         continue;
1797
1798                 err = __tipc_nl_add_link(net, msg,
1799                                          node->links[i].link, NLM_F_MULTI);
1800                 if (err)
1801                         return err;
1802         }
1803         *prev_link = 0;
1804
1805         return 0;
1806 }
1807
1808 int tipc_nl_link_dump(struct sk_buff *skb, struct netlink_callback *cb)
1809 {
1810         struct net *net = sock_net(skb->sk);
1811         struct tipc_net *tn = net_generic(net, tipc_net_id);
1812         struct tipc_node *node;
1813         struct tipc_nl_msg msg;
1814         u32 prev_node = cb->args[0];
1815         u32 prev_link = cb->args[1];
1816         int done = cb->args[2];
1817         int err;
1818
1819         if (done)
1820                 return 0;
1821
1822         msg.skb = skb;
1823         msg.portid = NETLINK_CB(cb->skb).portid;
1824         msg.seq = cb->nlh->nlmsg_seq;
1825
1826         rcu_read_lock();
1827         if (prev_node) {
1828                 node = tipc_node_find(net, prev_node);
1829                 if (!node) {
1830                         /* We never set seq or call nl_dump_check_consistent()
1831                          * this means that setting prev_seq here will cause the
1832                          * consistence check to fail in the netlink callback
1833                          * handler. Resulting in the last NLMSG_DONE message
1834                          * having the NLM_F_DUMP_INTR flag set.
1835                          */
1836                         cb->prev_seq = 1;
1837                         goto out;
1838                 }
1839                 tipc_node_put(node);
1840
1841                 list_for_each_entry_continue_rcu(node, &tn->node_list,
1842                                                  list) {
1843                         tipc_node_lock(node);
1844                         err = __tipc_nl_add_node_links(net, &msg, node,
1845                                                        &prev_link);
1846                         tipc_node_unlock(node);
1847                         if (err)
1848                                 goto out;
1849
1850                         prev_node = node->addr;
1851                 }
1852         } else {
1853                 err = tipc_nl_add_bc_link(net, &msg);
1854                 if (err)
1855                         goto out;
1856
1857                 list_for_each_entry_rcu(node, &tn->node_list, list) {
1858                         tipc_node_lock(node);
1859                         err = __tipc_nl_add_node_links(net, &msg, node,
1860                                                        &prev_link);
1861                         tipc_node_unlock(node);
1862                         if (err)
1863                                 goto out;
1864
1865                         prev_node = node->addr;
1866                 }
1867         }
1868         done = 1;
1869 out:
1870         rcu_read_unlock();
1871
1872         cb->args[0] = prev_node;
1873         cb->args[1] = prev_link;
1874         cb->args[2] = done;
1875
1876         return skb->len;
1877 }
1878
1879 int tipc_nl_link_get(struct sk_buff *skb, struct genl_info *info)
1880 {
1881         struct net *net = genl_info_net(info);
1882         struct tipc_nl_msg msg;
1883         char *name;
1884         int err;
1885
1886         msg.portid = info->snd_portid;
1887         msg.seq = info->snd_seq;
1888
1889         if (!info->attrs[TIPC_NLA_LINK_NAME])
1890                 return -EINVAL;
1891         name = nla_data(info->attrs[TIPC_NLA_LINK_NAME]);
1892
1893         msg.skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
1894         if (!msg.skb)
1895                 return -ENOMEM;
1896
1897         if (strcmp(name, tipc_bclink_name) == 0) {
1898                 err = tipc_nl_add_bc_link(net, &msg);
1899                 if (err) {
1900                         nlmsg_free(msg.skb);
1901                         return err;
1902                 }
1903         } else {
1904                 int bearer_id;
1905                 struct tipc_node *node;
1906                 struct tipc_link *link;
1907
1908                 node = tipc_link_find_owner(net, name, &bearer_id);
1909                 if (!node)
1910                         return -EINVAL;
1911
1912                 tipc_node_lock(node);
1913                 link = node->links[bearer_id].link;
1914                 if (!link) {
1915                         tipc_node_unlock(node);
1916                         nlmsg_free(msg.skb);
1917                         return -EINVAL;
1918                 }
1919
1920                 err = __tipc_nl_add_link(net, &msg, link, 0);
1921                 tipc_node_unlock(node);
1922                 if (err) {
1923                         nlmsg_free(msg.skb);
1924                         return err;
1925                 }
1926         }
1927
1928         return genlmsg_reply(msg.skb, info);
1929 }
1930
1931 int tipc_nl_link_reset_stats(struct sk_buff *skb, struct genl_info *info)
1932 {
1933         int err;
1934         char *link_name;
1935         unsigned int bearer_id;
1936         struct tipc_link *link;
1937         struct tipc_node *node;
1938         struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
1939         struct net *net = sock_net(skb->sk);
1940
1941         if (!info->attrs[TIPC_NLA_LINK])
1942                 return -EINVAL;
1943
1944         err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
1945                                info->attrs[TIPC_NLA_LINK],
1946                                tipc_nl_link_policy);
1947         if (err)
1948                 return err;
1949
1950         if (!attrs[TIPC_NLA_LINK_NAME])
1951                 return -EINVAL;
1952
1953         link_name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
1954
1955         if (strcmp(link_name, tipc_bclink_name) == 0) {
1956                 err = tipc_bclink_reset_stats(net);
1957                 if (err)
1958                         return err;
1959                 return 0;
1960         }
1961
1962         node = tipc_link_find_owner(net, link_name, &bearer_id);
1963         if (!node)
1964                 return -EINVAL;
1965
1966         tipc_node_lock(node);
1967
1968         link = node->links[bearer_id].link;
1969         if (!link) {
1970                 tipc_node_unlock(node);
1971                 return -EINVAL;
1972         }
1973
1974         link_reset_statistics(link);
1975
1976         tipc_node_unlock(node);
1977
1978         return 0;
1979 }