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 static int tipc_link_input(struct tipc_link *l, struct sk_buff *skb);
 115 static bool tipc_data_input(struct tipc_link *l, struct sk_buff *skb);
 116
 117 /*
 118  *  Simple non-static link routines (i.e. referenced outside this file)
 119  */
 120 bool tipc_link_is_up(struct tipc_link *l)
 121 {
 122         return link_is_up(l);
 123 }
 124
 125 bool tipc_link_is_reset(struct tipc_link *l)
 126 {
 127         return l->state & (LINK_RESET | LINK_FAILINGOVER | LINK_ESTABLISHING);
 128 }
 129
 130 bool tipc_link_is_synching(struct tipc_link *l)
 131 {
 132         return l->state == LINK_SYNCHING;
 133 }
 134
 135 bool tipc_link_is_failingover(struct tipc_link *l)
 136 {
 137         return l->state == LINK_FAILINGOVER;
 138 }
 139
 140 bool tipc_link_is_blocked(struct tipc_link *l)
 141 {
 142         return l->state & (LINK_RESETTING | LINK_PEER_RESET | LINK_FAILINGOVER);
 143 }
 144
 145 int tipc_link_is_active(struct tipc_link *l)
 146 {
 147         struct tipc_node *n = l->owner;
 148
 149         return (node_active_link(n, 0) == l) || (node_active_link(n, 1) == l);
 150 }
 151
 152 /**
 153  * tipc_link_create - create a new link
 154  * @n_ptr: pointer to associated node
 155  * @b_ptr: pointer to associated bearer
 156  * @media_addr: media address to use when sending messages over link
 157  *
 158  * Returns pointer to link.
 159  */
 160 struct tipc_link *tipc_link_create(struct tipc_node *n_ptr,
 161                                    struct tipc_bearer *b_ptr,
 162                                    const struct tipc_media_addr *media_addr,
 163                                    struct sk_buff_head *inputq,
 164                                    struct sk_buff_head *namedq)
 165 {
 166         struct tipc_net *tn = net_generic(n_ptr->net, tipc_net_id);
 167         struct tipc_link *l_ptr;
 168         struct tipc_msg *msg;
 169         char *if_name;
 170         char addr_string[16];
 171         u32 peer = n_ptr->addr;
 172
 173         if (n_ptr->link_cnt >= MAX_BEARERS) {
 174                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 175                 pr_err("Cannot establish %uth link to %s. Max %u allowed.\n",
 176                        n_ptr->link_cnt, addr_string, MAX_BEARERS);
 177                 return NULL;
 178         }
 179
 180         if (n_ptr->links[b_ptr->identity].link) {
 181                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 182                 pr_err("Attempt to establish second link on <%s> to %s\n",
 183                        b_ptr->name, addr_string);
 184                 return NULL;
 185         }
 186
 187         l_ptr = kzalloc(sizeof(*l_ptr), GFP_ATOMIC);
 188         if (!l_ptr) {
 189                 pr_warn("Link creation failed, no memory\n");
 190                 return NULL;
 191         }
 192         l_ptr->addr = peer;
 193         if_name = strchr(b_ptr->name, ':') + 1;
 194         sprintf(l_ptr->name, "%u.%u.%u:%s-%u.%u.%u:unknown",
 195                 tipc_zone(tn->own_addr), tipc_cluster(tn->own_addr),
 196                 tipc_node(tn->own_addr),
 197                 if_name,
 198                 tipc_zone(peer), tipc_cluster(peer), tipc_node(peer));
 199                 /* note: peer i/f name is updated by reset/activate message */
 200         memcpy(&l_ptr->media_addr, media_addr, sizeof(*media_addr));
 201         l_ptr->owner = n_ptr;
 202         l_ptr->peer_session = WILDCARD_SESSION;
 203         l_ptr->bearer_id = b_ptr->identity;
 204         l_ptr->tolerance = b_ptr->tolerance;
 205         l_ptr->snd_nxt = 1;
 206         l_ptr->rcv_nxt = 1;
 207         l_ptr->state = LINK_RESET;
 208
 209         l_ptr->pmsg = (struct tipc_msg *)&l_ptr->proto_msg;
 210         msg = l_ptr->pmsg;
 211         tipc_msg_init(tn->own_addr, msg, LINK_PROTOCOL, RESET_MSG, INT_H_SIZE,
 212                       l_ptr->addr);
 213         msg_set_size(msg, sizeof(l_ptr->proto_msg));
 214         msg_set_session(msg, (tn->random & 0xffff));
 215         msg_set_bearer_id(msg, b_ptr->identity);
 216         strcpy((char *)msg_data(msg), if_name);
 217         l_ptr->net_plane = b_ptr->net_plane;
 218         l_ptr->advertised_mtu = b_ptr->mtu;
 219         l_ptr->mtu = l_ptr->advertised_mtu;
 220         l_ptr->priority = b_ptr->priority;
 221         tipc_link_set_queue_limits(l_ptr, b_ptr->window);
 222         l_ptr->snd_nxt = 1;
 223         __skb_queue_head_init(&l_ptr->transmq);
 224         __skb_queue_head_init(&l_ptr->backlogq);
 225         __skb_queue_head_init(&l_ptr->deferdq);
 226         skb_queue_head_init(&l_ptr->wakeupq);
 227         l_ptr->inputq = inputq;
 228         l_ptr->namedq = namedq;
 229         skb_queue_head_init(l_ptr->inputq);
 230         link_reset_statistics(l_ptr);
 231         tipc_node_attach_link(n_ptr, l_ptr);
 232         return l_ptr;
 233 }
 234
 235 /* tipc_link_build_bcast_sync_msg() - synchronize broadcast link endpoints.
 236  *
 237  * Give a newly added peer node the sequence number where it should
 238  * start receiving and acking broadcast packets.
 239  */
 240 void tipc_link_build_bcast_sync_msg(struct tipc_link *l,
 241                                     struct sk_buff_head *xmitq)
 242 {
 243         struct sk_buff *skb;
 244         struct sk_buff_head list;
 245         u16 last_sent;
 246
 247         skb = tipc_msg_create(BCAST_PROTOCOL, STATE_MSG, INT_H_SIZE,
 248                               0, l->addr, link_own_addr(l), 0, 0, 0);
 249         if (!skb)
 250                 return;
 251         last_sent = tipc_bclink_get_last_sent(l->owner->net);
 252         msg_set_last_bcast(buf_msg(skb), last_sent);
 253         __skb_queue_head_init(&list);
 254         __skb_queue_tail(&list, skb);
 255         tipc_link_xmit(l, &list, xmitq);
 256 }
 257
 258 /**
 259  * tipc_link_fsm_evt - link finite state machine
 260  * @l: pointer to link
 261  * @evt: state machine event to be processed
 262  */
 263 int tipc_link_fsm_evt(struct tipc_link *l, int evt)
 264 {
 265         int rc = 0;
 266
 267         switch (l->state) {
 268         case LINK_RESETTING:
 269                 switch (evt) {
 270                 case LINK_PEER_RESET_EVT:
 271                         l->state = LINK_PEER_RESET;
 272                         break;
 273                 case LINK_RESET_EVT:
 274                         l->state = LINK_RESET;
 275                         break;
 276                 case LINK_FAILURE_EVT:
 277                 case LINK_FAILOVER_BEGIN_EVT:
 278                 case LINK_ESTABLISH_EVT:
 279                 case LINK_FAILOVER_END_EVT:
 280                 case LINK_SYNCH_BEGIN_EVT:
 281                 case LINK_SYNCH_END_EVT:
 282                 default:
 283                         goto illegal_evt;
 284                 }
 285                 break;
 286         case LINK_RESET:
 287                 switch (evt) {
 288                 case LINK_PEER_RESET_EVT:
 289                         l->state = LINK_ESTABLISHING;
 290                         break;
 291                 case LINK_FAILOVER_BEGIN_EVT:
 292                         l->state = LINK_FAILINGOVER;
 293                 case LINK_FAILURE_EVT:
 294                 case LINK_RESET_EVT:
 295                 case LINK_ESTABLISH_EVT:
 296                 case LINK_FAILOVER_END_EVT:
 297                         break;
 298                 case LINK_SYNCH_BEGIN_EVT:
 299                 case LINK_SYNCH_END_EVT:
 300                 default:
 301                         goto illegal_evt;
 302                 }
 303                 break;
 304         case LINK_PEER_RESET:
 305                 switch (evt) {
 306                 case LINK_RESET_EVT:
 307                         l->state = LINK_ESTABLISHING;
 308                         break;
 309                 case LINK_PEER_RESET_EVT:
 310                 case LINK_ESTABLISH_EVT:
 311                 case LINK_FAILURE_EVT:
 312                         break;
 313                 case LINK_SYNCH_BEGIN_EVT:
 314                 case LINK_SYNCH_END_EVT:
 315                 case LINK_FAILOVER_BEGIN_EVT:
 316                 case LINK_FAILOVER_END_EVT:
 317                 default:
 318                         goto illegal_evt;
 319                 }
 320                 break;
 321         case LINK_FAILINGOVER:
 322                 switch (evt) {
 323                 case LINK_FAILOVER_END_EVT:
 324                         l->state = LINK_RESET;
 325                         break;
 326                 case LINK_PEER_RESET_EVT:
 327                 case LINK_RESET_EVT:
 328                 case LINK_ESTABLISH_EVT:
 329                 case LINK_FAILURE_EVT:
 330                         break;
 331                 case LINK_FAILOVER_BEGIN_EVT:
 332                 case LINK_SYNCH_BEGIN_EVT:
 333                 case LINK_SYNCH_END_EVT:
 334                 default:
 335                         goto illegal_evt;
 336                 }
 337                 break;
 338         case LINK_ESTABLISHING:
 339                 switch (evt) {
 340                 case LINK_ESTABLISH_EVT:
 341                         l->state = LINK_ESTABLISHED;
 342                         rc |= TIPC_LINK_UP_EVT;
 343                         break;
 344                 case LINK_FAILOVER_BEGIN_EVT:
 345                         l->state = LINK_FAILINGOVER;
 346                         break;
 347                 case LINK_PEER_RESET_EVT:
 348                 case LINK_RESET_EVT:
 349                 case LINK_FAILURE_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                         break;
 373                 case LINK_SYNCH_BEGIN_EVT:
 374                         l->state = LINK_SYNCHING;
 375                         break;
 376                 case LINK_SYNCH_END_EVT:
 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         tipc_link_fsm_evt(l, LINK_RESET_EVT);
 600
 601         /* Link is down, accept any session */
 602         l->peer_session = WILDCARD_SESSION;
 603
 604         /* If peer is up, it only accepts an incremented session number */
 605         msg_set_session(l->pmsg, msg_session(l->pmsg) + 1);
 606
 607         /* Prepare for renewed mtu size negotiation */
 608         l->mtu = l->advertised_mtu;
 609
 610         /* Clean up all queues: */
 611         __skb_queue_purge(&l->transmq);
 612         __skb_queue_purge(&l->deferdq);
 613         skb_queue_splice_init(&l->wakeupq, l->inputq);
 614
 615         tipc_link_purge_backlog(l);
 616         kfree_skb(l->reasm_buf);
 617         kfree_skb(l->failover_reasm_skb);
 618         l->reasm_buf = NULL;
 619         l->failover_reasm_skb = NULL;
 620         l->rcv_unacked = 0;
 621         l->snd_nxt = 1;
 622         l->rcv_nxt = 1;
 623         l->silent_intv_cnt = 0;
 624         l->stats.recv_info = 0;
 625         l->stale_count = 0;
 626         link_reset_statistics(l);
 627 }
 628
 629 /**
 630  * __tipc_link_xmit(): same as tipc_link_xmit, but destlink is known & locked
 631  * @link: link to use
 632  * @list: chain of buffers containing message
 633  *
 634  * Consumes the buffer chain, except when returning an error code,
 635  * Returns 0 if success, or errno: -ELINKCONG, -EMSGSIZE or -ENOBUFS
 636  * Messages at TIPC_SYSTEM_IMPORTANCE are always accepted
 637  */
 638 int __tipc_link_xmit(struct net *net, struct tipc_link *link,
 639                      struct sk_buff_head *list)
 640 {
 641         struct tipc_msg *msg = buf_msg(skb_peek(list));
 642         unsigned int maxwin = link->window;
 643         unsigned int i, imp = msg_importance(msg);
 644         uint mtu = link->mtu;
 645         u16 ack = mod(link->rcv_nxt - 1);
 646         u16 seqno = link->snd_nxt;
 647         u16 bc_last_in = link->owner->bclink.last_in;
 648         struct tipc_media_addr *addr = &link->media_addr;
 649         struct sk_buff_head *transmq = &link->transmq;
 650         struct sk_buff_head *backlogq = &link->backlogq;
 651         struct sk_buff *skb, *bskb;
 652
 653         /* Match msg importance against this and all higher backlog limits: */
 654         for (i = imp; i <= TIPC_SYSTEM_IMPORTANCE; i++) {
 655                 if (unlikely(link->backlog[i].len >= link->backlog[i].limit))
 656                         return link_schedule_user(link, list);
 657         }
 658         if (unlikely(msg_size(msg) > mtu))
 659                 return -EMSGSIZE;
 660
 661         /* Prepare each packet for sending, and add to relevant queue: */
 662         while (skb_queue_len(list)) {
 663                 skb = skb_peek(list);
 664                 msg = buf_msg(skb);
 665                 msg_set_seqno(msg, seqno);
 666                 msg_set_ack(msg, ack);
 667                 msg_set_bcast_ack(msg, bc_last_in);
 668
 669                 if (likely(skb_queue_len(transmq) < maxwin)) {
 670                         __skb_dequeue(list);
 671                         __skb_queue_tail(transmq, skb);
 672                         tipc_bearer_send(net, link->bearer_id, skb, addr);
 673                         link->rcv_unacked = 0;
 674                         seqno++;
 675                         continue;
 676                 }
 677                 if (tipc_msg_bundle(skb_peek_tail(backlogq), msg, mtu)) {
 678                         kfree_skb(__skb_dequeue(list));
 679                         link->stats.sent_bundled++;
 680                         continue;
 681                 }
 682                 if (tipc_msg_make_bundle(&bskb, msg, mtu, link->addr)) {
 683                         kfree_skb(__skb_dequeue(list));
 684                         __skb_queue_tail(backlogq, bskb);
 685                         link->backlog[msg_importance(buf_msg(bskb))].len++;
 686                         link->stats.sent_bundled++;
 687                         link->stats.sent_bundles++;
 688                         continue;
 689                 }
 690                 link->backlog[imp].len += skb_queue_len(list);
 691                 skb_queue_splice_tail_init(list, backlogq);
 692         }
 693         link->snd_nxt = seqno;
 694         return 0;
 695 }
 696
 697 /**
 698  * tipc_link_xmit(): enqueue buffer list according to queue situation
 699  * @link: link to use
 700  * @list: chain of buffers containing message
 701  * @xmitq: returned list of packets to be sent by caller
 702  *
 703  * Consumes the buffer chain, except when returning -ELINKCONG,
 704  * since the caller then may want to make more send attempts.
 705  * Returns 0 if success, or errno: -ELINKCONG, -EMSGSIZE or -ENOBUFS
 706  * Messages at TIPC_SYSTEM_IMPORTANCE are always accepted
 707  */
 708 int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *list,
 709                    struct sk_buff_head *xmitq)
 710 {
 711         struct tipc_msg *hdr = buf_msg(skb_peek(list));
 712         unsigned int maxwin = l->window;
 713         unsigned int i, imp = msg_importance(hdr);
 714         unsigned int mtu = l->mtu;
 715         u16 ack = l->rcv_nxt - 1;
 716         u16 seqno = l->snd_nxt;
 717         u16 bc_last_in = l->owner->bclink.last_in;
 718         struct sk_buff_head *transmq = &l->transmq;
 719         struct sk_buff_head *backlogq = &l->backlogq;
 720         struct sk_buff *skb, *_skb, *bskb;
 721
 722         /* Match msg importance against this and all higher backlog limits: */
 723         for (i = imp; i <= TIPC_SYSTEM_IMPORTANCE; i++) {
 724                 if (unlikely(l->backlog[i].len >= l->backlog[i].limit))
 725                         return link_schedule_user(l, list);
 726         }
 727         if (unlikely(msg_size(hdr) > mtu))
 728                 return -EMSGSIZE;
 729
 730         /* Prepare each packet for sending, and add to relevant queue: */
 731         while (skb_queue_len(list)) {
 732                 skb = skb_peek(list);
 733                 hdr = buf_msg(skb);
 734                 msg_set_seqno(hdr, seqno);
 735                 msg_set_ack(hdr, ack);
 736                 msg_set_bcast_ack(hdr, bc_last_in);
 737
 738                 if (likely(skb_queue_len(transmq) < maxwin)) {
 739                         _skb = skb_clone(skb, GFP_ATOMIC);
 740                         if (!_skb)
 741                                 return -ENOBUFS;
 742                         __skb_dequeue(list);
 743                         __skb_queue_tail(transmq, skb);
 744                         __skb_queue_tail(xmitq, _skb);
 745                         l->rcv_unacked = 0;
 746                         seqno++;
 747                         continue;
 748                 }
 749                 if (tipc_msg_bundle(skb_peek_tail(backlogq), hdr, mtu)) {
 750                         kfree_skb(__skb_dequeue(list));
 751                         l->stats.sent_bundled++;
 752                         continue;
 753                 }
 754                 if (tipc_msg_make_bundle(&bskb, hdr, mtu, l->addr)) {
 755                         kfree_skb(__skb_dequeue(list));
 756                         __skb_queue_tail(backlogq, bskb);
 757                         l->backlog[msg_importance(buf_msg(bskb))].len++;
 758                         l->stats.sent_bundled++;
 759                         l->stats.sent_bundles++;
 760                         continue;
 761                 }
 762                 l->backlog[imp].len += skb_queue_len(list);
 763                 skb_queue_splice_tail_init(list, backlogq);
 764         }
 765         l->snd_nxt = seqno;
 766         return 0;
 767 }
 768
 769 /*
 770  * tipc_link_sync_rcv - synchronize broadcast link endpoints.
 771  * Receive the sequence number where we should start receiving and
 772  * acking broadcast packets from a newly added peer node, and open
 773  * up for reception of such packets.
 774  *
 775  * Called with node locked
 776  */
 777 static void tipc_link_sync_rcv(struct tipc_node *n, struct sk_buff *buf)
 778 {
 779         struct tipc_msg *msg = buf_msg(buf);
 780
 781         n->bclink.last_sent = n->bclink.last_in = msg_last_bcast(msg);
 782         n->bclink.recv_permitted = true;
 783         kfree_skb(buf);
 784 }
 785
 786 /*
 787  * tipc_link_push_packets - push unsent packets to bearer
 788  *
 789  * Push out the unsent messages of a link where congestion
 790  * has abated. Node is locked.
 791  *
 792  * Called with node locked
 793  */
 794 void tipc_link_push_packets(struct tipc_link *link)
 795 {
 796         struct sk_buff *skb;
 797         struct tipc_msg *msg;
 798         u16 seqno = link->snd_nxt;
 799         u16 ack = mod(link->rcv_nxt - 1);
 800
 801         while (skb_queue_len(&link->transmq) < link->window) {
 802                 skb = __skb_dequeue(&link->backlogq);
 803                 if (!skb)
 804                         break;
 805                 msg = buf_msg(skb);
 806                 link->backlog[msg_importance(msg)].len--;
 807                 msg_set_ack(msg, ack);
 808                 msg_set_seqno(msg, seqno);
 809                 seqno = mod(seqno + 1);
 810                 msg_set_bcast_ack(msg, link->owner->bclink.last_in);
 811                 link->rcv_unacked = 0;
 812                 __skb_queue_tail(&link->transmq, skb);
 813                 tipc_bearer_send(link->owner->net, link->bearer_id,
 814                                  skb, &link->media_addr);
 815         }
 816         link->snd_nxt = seqno;
 817 }
 818
 819 void tipc_link_advance_backlog(struct tipc_link *l, struct sk_buff_head *xmitq)
 820 {
 821         struct sk_buff *skb, *_skb;
 822         struct tipc_msg *hdr;
 823         u16 seqno = l->snd_nxt;
 824         u16 ack = l->rcv_nxt - 1;
 825
 826         while (skb_queue_len(&l->transmq) < l->window) {
 827                 skb = skb_peek(&l->backlogq);
 828                 if (!skb)
 829                         break;
 830                 _skb = skb_clone(skb, GFP_ATOMIC);
 831                 if (!_skb)
 832                         break;
 833                 __skb_dequeue(&l->backlogq);
 834                 hdr = buf_msg(skb);
 835                 l->backlog[msg_importance(hdr)].len--;
 836                 __skb_queue_tail(&l->transmq, skb);
 837                 __skb_queue_tail(xmitq, _skb);
 838                 msg_set_ack(hdr, ack);
 839                 msg_set_seqno(hdr, seqno);
 840                 msg_set_bcast_ack(hdr, l->owner->bclink.last_in);
 841                 l->rcv_unacked = 0;
 842                 seqno++;
 843         }
 844         l->snd_nxt = seqno;
 845 }
 846
 847 static void link_retransmit_failure(struct tipc_link *l_ptr,
 848                                     struct sk_buff *buf)
 849 {
 850         struct tipc_msg *msg = buf_msg(buf);
 851         struct net *net = l_ptr->owner->net;
 852
 853         pr_warn("Retransmission failure on link <%s>\n", l_ptr->name);
 854
 855         if (l_ptr->addr) {
 856                 /* Handle failure on standard link */
 857                 link_print(l_ptr, "Resetting link ");
 858                 pr_info("Failed msg: usr %u, typ %u, len %u, err %u\n",
 859                         msg_user(msg), msg_type(msg), msg_size(msg),
 860                         msg_errcode(msg));
 861                 pr_info("sqno %u, prev: %x, src: %x\n",
 862                         msg_seqno(msg), msg_prevnode(msg), msg_orignode(msg));
 863         } else {
 864                 /* Handle failure on broadcast link */
 865                 struct tipc_node *n_ptr;
 866                 char addr_string[16];
 867
 868                 pr_info("Msg seq number: %u,  ", msg_seqno(msg));
 869                 pr_cont("Outstanding acks: %lu\n",
 870                         (unsigned long) TIPC_SKB_CB(buf)->handle);
 871
 872                 n_ptr = tipc_bclink_retransmit_to(net);
 873
 874                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 875                 pr_info("Broadcast link info for %s\n", addr_string);
 876                 pr_info("Reception permitted: %d,  Acked: %u\n",
 877                         n_ptr->bclink.recv_permitted,
 878                         n_ptr->bclink.acked);
 879                 pr_info("Last in: %u,  Oos state: %u,  Last sent: %u\n",
 880                         n_ptr->bclink.last_in,
 881                         n_ptr->bclink.oos_state,
 882                         n_ptr->bclink.last_sent);
 883
 884                 n_ptr->action_flags |= TIPC_BCAST_RESET;
 885                 l_ptr->stale_count = 0;
 886         }
 887 }
 888
 889 void tipc_link_retransmit(struct tipc_link *l_ptr, struct sk_buff *skb,
 890                           u32 retransmits)
 891 {
 892         struct tipc_msg *msg;
 893
 894         if (!skb)
 895                 return;
 896
 897         msg = buf_msg(skb);
 898
 899         /* Detect repeated retransmit failures */
 900         if (l_ptr->last_retransm == msg_seqno(msg)) {
 901                 if (++l_ptr->stale_count > 100) {
 902                         link_retransmit_failure(l_ptr, skb);
 903                         return;
 904                 }
 905         } else {
 906                 l_ptr->last_retransm = msg_seqno(msg);
 907                 l_ptr->stale_count = 1;
 908         }
 909
 910         skb_queue_walk_from(&l_ptr->transmq, skb) {
 911                 if (!retransmits)
 912                         break;
 913                 msg = buf_msg(skb);
 914                 msg_set_ack(msg, mod(l_ptr->rcv_nxt - 1));
 915                 msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
 916                 tipc_bearer_send(l_ptr->owner->net, l_ptr->bearer_id, skb,
 917                                  &l_ptr->media_addr);
 918                 retransmits--;
 919                 l_ptr->stats.retransmitted++;
 920         }
 921 }
 922
 923 static int tipc_link_retransm(struct tipc_link *l, int retransm,
 924                               struct sk_buff_head *xmitq)
 925 {
 926         struct sk_buff *_skb, *skb = skb_peek(&l->transmq);
 927         struct tipc_msg *hdr;
 928
 929         if (!skb)
 930                 return 0;
 931
 932         /* Detect repeated retransmit failures on same packet */
 933         if (likely(l->last_retransm != buf_seqno(skb))) {
 934                 l->last_retransm = buf_seqno(skb);
 935                 l->stale_count = 1;
 936         } else if (++l->stale_count > 100) {
 937                 link_retransmit_failure(l, skb);
 938                 return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
 939         }
 940         skb_queue_walk(&l->transmq, skb) {
 941                 if (!retransm)
 942                         return 0;
 943                 hdr = buf_msg(skb);
 944                 _skb = __pskb_copy(skb, MIN_H_SIZE, GFP_ATOMIC);
 945                 if (!_skb)
 946                         return 0;
 947                 hdr = buf_msg(_skb);
 948                 msg_set_ack(hdr, l->rcv_nxt - 1);
 949                 msg_set_bcast_ack(hdr, l->owner->bclink.last_in);
 950                 _skb->priority = TC_PRIO_CONTROL;
 951                 __skb_queue_tail(xmitq, _skb);
 952                 retransm--;
 953                 l->stats.retransmitted++;
 954         }
 955         return 0;
 956 }
 957
 958 /* tipc_data_input - deliver data and name distr msgs to upper layer
 959  *
 960  * Consumes buffer if message is of right type
 961  * Node lock must be held
 962  */
 963 static bool tipc_data_input(struct tipc_link *link, struct sk_buff *skb)
 964 {
 965         struct tipc_node *node = link->owner;
 966         struct tipc_msg *msg = buf_msg(skb);
 967
 968         switch (msg_user(msg)) {
 969         case TIPC_LOW_IMPORTANCE:
 970         case TIPC_MEDIUM_IMPORTANCE:
 971         case TIPC_HIGH_IMPORTANCE:
 972         case TIPC_CRITICAL_IMPORTANCE:
 973         case CONN_MANAGER:
 974                 skb_queue_tail(link->inputq, skb);
 975                 return true;
 976         case NAME_DISTRIBUTOR:
 977                 node->bclink.recv_permitted = true;
 978                 skb_queue_tail(link->namedq, skb);
 979                 return true;
 980         case MSG_BUNDLER:
 981         case TUNNEL_PROTOCOL:
 982         case MSG_FRAGMENTER:
 983         case BCAST_PROTOCOL:
 984                 return false;
 985         default:
 986                 pr_warn("Dropping received illegal msg type\n");
 987                 kfree_skb(skb);
 988                 return false;
 989         };
 990 }
 991
 992 /* tipc_link_input - process packet that has passed link protocol check
 993  *
 994  * Consumes buffer
 995  */
 996 static int tipc_link_input(struct tipc_link *l, struct sk_buff *skb)
 997 {
 998         struct tipc_node *node = l->owner;
 999         struct tipc_msg *hdr = buf_msg(skb);
1000         struct sk_buff **reasm_skb = &l->reasm_buf;
1001         struct sk_buff *iskb;
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))
1020                         return rc;
1021                 usr = msg_user(hdr);
1022                 reasm_skb = &l->failover_reasm_skb;
1023         }
1024
1025         if (usr == MSG_BUNDLER) {
1026                 l->stats.recv_bundles++;
1027                 l->stats.recv_bundled += msg_msgcnt(hdr);
1028                 while (tipc_msg_extract(skb, &iskb, &pos))
1029                         tipc_data_input(l, iskb);
1030                 return 0;
1031         } else if (usr == MSG_FRAGMENTER) {
1032                 l->stats.recv_fragments++;
1033                 if (tipc_buf_append(reasm_skb, &skb)) {
1034                         l->stats.recv_fragmented++;
1035                         tipc_data_input(l, skb);
1036                 } else if (!*reasm_skb) {
1037                         return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1038                 }
1039                 return 0;
1040         } else if (usr == BCAST_PROTOCOL) {
1041                 tipc_link_sync_rcv(node, skb);
1042                 return 0;
1043         }
1044 drop:
1045         kfree_skb(skb);
1046         return 0;
1047 }
1048
1049 static bool tipc_link_release_pkts(struct tipc_link *l, u16 acked)
1050 {
1051         bool released = false;
1052         struct sk_buff *skb, *tmp;
1053
1054         skb_queue_walk_safe(&l->transmq, skb, tmp) {
1055                 if (more(buf_seqno(skb), acked))
1056                         break;
1057                 __skb_unlink(skb, &l->transmq);
1058                 kfree_skb(skb);
1059                 released = true;
1060         }
1061         return released;
1062 }
1063
1064 /* tipc_link_rcv - process TIPC packets/messages arriving from off-node
1065  * @link: the link that should handle the message
1066  * @skb: TIPC packet
1067  * @xmitq: queue to place packets to be sent after this call
1068  */
1069 int tipc_link_rcv(struct tipc_link *l, struct sk_buff *skb,
1070                   struct sk_buff_head *xmitq)
1071 {
1072         struct sk_buff_head *arrvq = &l->deferdq;
1073         struct tipc_msg *hdr;
1074         u16 seqno, rcv_nxt;
1075         int rc = 0;
1076
1077         if (unlikely(!__tipc_skb_queue_sorted(arrvq, skb))) {
1078                 if (!(skb_queue_len(arrvq) % TIPC_NACK_INTV))
1079                         tipc_link_build_proto_msg(l, STATE_MSG, 0,
1080                                                   0, 0, 0, xmitq);
1081                 return rc;
1082         }
1083
1084         while ((skb = skb_peek(arrvq))) {
1085                 hdr = buf_msg(skb);
1086
1087                 /* Verify and update link state */
1088                 if (unlikely(msg_user(hdr) == LINK_PROTOCOL)) {
1089                         __skb_dequeue(arrvq);
1090                         rc = tipc_link_proto_rcv(l, skb, xmitq);
1091                         continue;
1092                 }
1093
1094                 if (unlikely(!link_is_up(l))) {
1095                         rc = tipc_link_fsm_evt(l, LINK_ESTABLISH_EVT);
1096                         if (!link_is_up(l)) {
1097                                 kfree_skb(__skb_dequeue(arrvq));
1098                                 return rc;
1099                         }
1100                 }
1101
1102                 l->silent_intv_cnt = 0;
1103
1104                 /* Forward queues and wake up waiting users */
1105                 if (likely(tipc_link_release_pkts(l, msg_ack(hdr)))) {
1106                         tipc_link_advance_backlog(l, xmitq);
1107                         if (unlikely(!skb_queue_empty(&l->wakeupq)))
1108                                 link_prepare_wakeup(l);
1109                 }
1110
1111                 /* Defer reception if there is a gap in the sequence */
1112                 seqno = msg_seqno(hdr);
1113                 rcv_nxt = l->rcv_nxt;
1114                 if (unlikely(less(rcv_nxt, seqno))) {
1115                         l->stats.deferred_recv++;
1116                         return rc;
1117                 }
1118
1119                 __skb_dequeue(arrvq);
1120
1121                 /* Drop if packet already received */
1122                 if (unlikely(more(rcv_nxt, seqno))) {
1123                         l->stats.duplicates++;
1124                         kfree_skb(skb);
1125                         return rc;
1126                 }
1127
1128                 /* Packet can be delivered */
1129                 l->rcv_nxt++;
1130                 l->stats.recv_info++;
1131                 if (unlikely(!tipc_data_input(l, skb)))
1132                         rc = tipc_link_input(l, skb);
1133
1134                 /* Ack at regular intervals */
1135                 if (unlikely(++l->rcv_unacked >= TIPC_MIN_LINK_WIN)) {
1136                         l->rcv_unacked = 0;
1137                         l->stats.sent_acks++;
1138                         tipc_link_build_proto_msg(l, STATE_MSG,
1139                                                   0, 0, 0, 0, xmitq);
1140                 }
1141         }
1142         return rc;
1143 }
1144
1145 /**
1146  * tipc_link_defer_pkt - Add out-of-sequence message to deferred reception queue
1147  *
1148  * Returns increase in queue length (i.e. 0 or 1)
1149  */
1150 u32 tipc_link_defer_pkt(struct sk_buff_head *list, struct sk_buff *skb)
1151 {
1152         struct sk_buff *skb1;
1153         u16 seq_no = buf_seqno(skb);
1154
1155         /* Empty queue ? */
1156         if (skb_queue_empty(list)) {
1157                 __skb_queue_tail(list, skb);
1158                 return 1;
1159         }
1160
1161         /* Last ? */
1162         if (less(buf_seqno(skb_peek_tail(list)), seq_no)) {
1163                 __skb_queue_tail(list, skb);
1164                 return 1;
1165         }
1166
1167         /* Locate insertion point in queue, then insert; discard if duplicate */
1168         skb_queue_walk(list, skb1) {
1169                 u16 curr_seqno = buf_seqno(skb1);
1170
1171                 if (seq_no == curr_seqno) {
1172                         kfree_skb(skb);
1173                         return 0;
1174                 }
1175
1176                 if (less(seq_no, curr_seqno))
1177                         break;
1178         }
1179
1180         __skb_queue_before(list, skb1, skb);
1181         return 1;
1182 }
1183
1184 /*
1185  * Send protocol message to the other endpoint.
1186  */
1187 void tipc_link_proto_xmit(struct tipc_link *l, u32 msg_typ, int probe_msg,
1188                           u32 gap, u32 tolerance, u32 priority)
1189 {
1190         struct sk_buff *skb = NULL;
1191         struct sk_buff_head xmitq;
1192
1193         __skb_queue_head_init(&xmitq);
1194         tipc_link_build_proto_msg(l, msg_typ, probe_msg, gap,
1195                                   tolerance, priority, &xmitq);
1196         skb = __skb_dequeue(&xmitq);
1197         if (!skb)
1198                 return;
1199         tipc_bearer_send(l->owner->net, l->bearer_id, skb, &l->media_addr);
1200         l->rcv_unacked = 0;
1201         kfree_skb(skb);
1202 }
1203
1204 /* tipc_link_build_proto_msg: prepare link protocol message for transmission
1205  */
1206 static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
1207                                       u16 rcvgap, int tolerance, int priority,
1208                                       struct sk_buff_head *xmitq)
1209 {
1210         struct sk_buff *skb = NULL;
1211         struct tipc_msg *hdr = l->pmsg;
1212         u16 snd_nxt = l->snd_nxt;
1213         u16 rcv_nxt = l->rcv_nxt;
1214         u16 rcv_last = rcv_nxt - 1;
1215         int node_up = l->owner->bclink.recv_permitted;
1216
1217         /* Don't send protocol message during reset or link failover */
1218         if (tipc_link_is_blocked(l))
1219                 return;
1220
1221         msg_set_type(hdr, mtyp);
1222         msg_set_net_plane(hdr, l->net_plane);
1223         msg_set_bcast_ack(hdr, l->owner->bclink.last_in);
1224         msg_set_last_bcast(hdr, tipc_bclink_get_last_sent(l->owner->net));
1225         msg_set_link_tolerance(hdr, tolerance);
1226         msg_set_linkprio(hdr, priority);
1227         msg_set_redundant_link(hdr, node_up);
1228         msg_set_seq_gap(hdr, 0);
1229
1230         /* Compatibility: created msg must not be in sequence with pkt flow */
1231         msg_set_seqno(hdr, snd_nxt + U16_MAX / 2);
1232
1233         if (mtyp == STATE_MSG) {
1234                 if (!tipc_link_is_up(l))
1235                         return;
1236                 msg_set_next_sent(hdr, snd_nxt);
1237
1238                 /* Override rcvgap if there are packets in deferred queue */
1239                 if (!skb_queue_empty(&l->deferdq))
1240                         rcvgap = buf_seqno(skb_peek(&l->deferdq)) - rcv_nxt;
1241                 if (rcvgap) {
1242                         msg_set_seq_gap(hdr, rcvgap);
1243                         l->stats.sent_nacks++;
1244                 }
1245                 msg_set_ack(hdr, rcv_last);
1246                 msg_set_probe(hdr, probe);
1247                 if (probe)
1248                         l->stats.sent_probes++;
1249                 l->stats.sent_states++;
1250         } else {
1251                 /* RESET_MSG or ACTIVATE_MSG */
1252                 msg_set_max_pkt(hdr, l->advertised_mtu);
1253                 msg_set_ack(hdr, l->rcv_nxt - 1);
1254                 msg_set_next_sent(hdr, 1);
1255         }
1256         skb = tipc_buf_acquire(msg_size(hdr));
1257         if (!skb)
1258                 return;
1259         skb_copy_to_linear_data(skb, hdr, msg_size(hdr));
1260         skb->priority = TC_PRIO_CONTROL;
1261         __skb_queue_tail(xmitq, skb);
1262 }
1263
1264 /* tipc_link_tnl_prepare(): prepare and return a list of tunnel packets
1265  * with contents of the link's tranmsit and backlog queues.
1266  */
1267 void tipc_link_tnl_prepare(struct tipc_link *l, struct tipc_link *tnl,
1268                            int mtyp, struct sk_buff_head *xmitq)
1269 {
1270         struct sk_buff *skb, *tnlskb;
1271         struct tipc_msg *hdr, tnlhdr;
1272         struct sk_buff_head *queue = &l->transmq;
1273         struct sk_buff_head tmpxq, tnlq;
1274         u16 pktlen, pktcnt, seqno = l->snd_nxt;
1275
1276         if (!tnl)
1277                 return;
1278
1279         skb_queue_head_init(&tnlq);
1280         skb_queue_head_init(&tmpxq);
1281
1282         /* At least one packet required for safe algorithm => add dummy */
1283         skb = tipc_msg_create(TIPC_LOW_IMPORTANCE, TIPC_DIRECT_MSG,
1284                               BASIC_H_SIZE, 0, l->addr, link_own_addr(l),
1285                               0, 0, TIPC_ERR_NO_PORT);
1286         if (!skb) {
1287                 pr_warn("%sunable to create tunnel packet\n", link_co_err);
1288                 return;
1289         }
1290         skb_queue_tail(&tnlq, skb);
1291         tipc_link_xmit(l, &tnlq, &tmpxq);
1292         __skb_queue_purge(&tmpxq);
1293
1294         /* Initialize reusable tunnel packet header */
1295         tipc_msg_init(link_own_addr(l), &tnlhdr, TUNNEL_PROTOCOL,
1296                       mtyp, INT_H_SIZE, l->addr);
1297         pktcnt = skb_queue_len(&l->transmq) + skb_queue_len(&l->backlogq);
1298         msg_set_msgcnt(&tnlhdr, pktcnt);
1299         msg_set_bearer_id(&tnlhdr, l->peer_bearer_id);
1300 tnl:
1301         /* Wrap each packet into a tunnel packet */
1302         skb_queue_walk(queue, skb) {
1303                 hdr = buf_msg(skb);
1304                 if (queue == &l->backlogq)
1305                         msg_set_seqno(hdr, seqno++);
1306                 pktlen = msg_size(hdr);
1307                 msg_set_size(&tnlhdr, pktlen + INT_H_SIZE);
1308                 tnlskb = tipc_buf_acquire(pktlen + INT_H_SIZE);
1309                 if (!tnlskb) {
1310                         pr_warn("%sunable to send packet\n", link_co_err);
1311                         return;
1312                 }
1313                 skb_copy_to_linear_data(tnlskb, &tnlhdr, INT_H_SIZE);
1314                 skb_copy_to_linear_data_offset(tnlskb, INT_H_SIZE, hdr, pktlen);
1315                 __skb_queue_tail(&tnlq, tnlskb);
1316         }
1317         if (queue != &l->backlogq) {
1318                 queue = &l->backlogq;
1319                 goto tnl;
1320         }
1321
1322         tipc_link_xmit(tnl, &tnlq, xmitq);
1323
1324         if (mtyp == FAILOVER_MSG) {
1325                 tnl->drop_point = l->rcv_nxt;
1326                 tnl->failover_reasm_skb = l->reasm_buf;
1327                 l->reasm_buf = NULL;
1328         }
1329 }
1330
1331 /* tipc_link_proto_rcv(): receive link level protocol message :
1332  * Note that network plane id propagates through the network, and may
1333  * change at any time. The node with lowest numerical id determines
1334  * network plane
1335  */
1336 static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
1337                                struct sk_buff_head *xmitq)
1338 {
1339         struct tipc_msg *hdr = buf_msg(skb);
1340         u16 rcvgap = 0;
1341         u16 nacked_gap = msg_seq_gap(hdr);
1342         u16 peers_snd_nxt =  msg_next_sent(hdr);
1343         u16 peers_tol = msg_link_tolerance(hdr);
1344         u16 peers_prio = msg_linkprio(hdr);
1345         char *if_name;
1346         int rc = 0;
1347
1348         if (tipc_link_is_blocked(l))
1349                 goto exit;
1350
1351         if (link_own_addr(l) > msg_prevnode(hdr))
1352                 l->net_plane = msg_net_plane(hdr);
1353
1354         switch (msg_type(hdr)) {
1355         case RESET_MSG:
1356
1357                 /* Ignore duplicate RESET with old session number */
1358                 if ((less_eq(msg_session(hdr), l->peer_session)) &&
1359                     (l->peer_session != WILDCARD_SESSION))
1360                         break;
1361                 /* fall thru' */
1362
1363         case ACTIVATE_MSG:
1364
1365                 /* Complete own link name with peer's interface name */
1366                 if_name =  strrchr(l->name, ':') + 1;
1367                 if (sizeof(l->name) - (if_name - l->name) <= TIPC_MAX_IF_NAME)
1368                         break;
1369                 if (msg_data_sz(hdr) < TIPC_MAX_IF_NAME)
1370                         break;
1371                 strncpy(if_name, msg_data(hdr), TIPC_MAX_IF_NAME);
1372
1373                 /* Update own tolerance if peer indicates a non-zero value */
1374                 if (in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL))
1375                         l->tolerance = peers_tol;
1376
1377                 /* Update own priority if peer's priority is higher */
1378                 if (in_range(peers_prio, l->priority + 1, TIPC_MAX_LINK_PRI))
1379                         l->priority = peers_prio;
1380
1381                 if (msg_type(hdr) == RESET_MSG) {
1382                         rc |= tipc_link_fsm_evt(l, LINK_PEER_RESET_EVT);
1383                 } else if (!link_is_up(l)) {
1384                         tipc_link_fsm_evt(l, LINK_PEER_RESET_EVT);
1385                         rc |= tipc_link_fsm_evt(l, LINK_ESTABLISH_EVT);
1386                 }
1387                 l->peer_session = msg_session(hdr);
1388                 l->peer_bearer_id = msg_bearer_id(hdr);
1389                 if (l->mtu > msg_max_pkt(hdr))
1390                         l->mtu = msg_max_pkt(hdr);
1391                 break;
1392
1393         case STATE_MSG:
1394
1395                 /* Update own tolerance if peer indicates a non-zero value */
1396                 if (in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL))
1397                         l->tolerance = peers_tol;
1398
1399                 l->silent_intv_cnt = 0;
1400                 l->stats.recv_states++;
1401                 if (msg_probe(hdr))
1402                         l->stats.recv_probes++;
1403                 rc = tipc_link_fsm_evt(l, LINK_ESTABLISH_EVT);
1404                 if (!link_is_up(l))
1405                         break;
1406
1407                 /* Send NACK if peer has sent pkts we haven't received yet */
1408                 if (more(peers_snd_nxt, l->rcv_nxt))
1409                         rcvgap = peers_snd_nxt - l->rcv_nxt;
1410                 if (rcvgap || (msg_probe(hdr)))
1411                         tipc_link_build_proto_msg(l, STATE_MSG, 0, rcvgap,
1412                                                   0, 0, xmitq);
1413                 tipc_link_release_pkts(l, msg_ack(hdr));
1414
1415                 /* If NACK, retransmit will now start at right position */
1416                 if (nacked_gap) {
1417                         rc = tipc_link_retransm(l, nacked_gap, xmitq);
1418                         l->stats.recv_nacks++;
1419                 }
1420
1421                 tipc_link_advance_backlog(l, xmitq);
1422                 if (unlikely(!skb_queue_empty(&l->wakeupq)))
1423                         link_prepare_wakeup(l);
1424         }
1425 exit:
1426         kfree_skb(skb);
1427         return rc;
1428 }
1429
1430 void tipc_link_set_queue_limits(struct tipc_link *l, u32 win)
1431 {
1432         int max_bulk = TIPC_MAX_PUBLICATIONS / (l->mtu / ITEM_SIZE);
1433
1434         l->window = win;
1435         l->backlog[TIPC_LOW_IMPORTANCE].limit      = win / 2;
1436         l->backlog[TIPC_MEDIUM_IMPORTANCE].limit   = win;
1437         l->backlog[TIPC_HIGH_IMPORTANCE].limit     = win / 2 * 3;
1438         l->backlog[TIPC_CRITICAL_IMPORTANCE].limit = win * 2;
1439         l->backlog[TIPC_SYSTEM_IMPORTANCE].limit   = max_bulk;
1440 }
1441
1442 /* tipc_link_find_owner - locate owner node of link by link's name
1443  * @net: the applicable net namespace
1444  * @name: pointer to link name string
1445  * @bearer_id: pointer to index in 'node->links' array where the link was found.
1446  *
1447  * Returns pointer to node owning the link, or 0 if no matching link is found.
1448  */
1449 static struct tipc_node *tipc_link_find_owner(struct net *net,
1450                                               const char *link_name,
1451                                               unsigned int *bearer_id)
1452 {
1453         struct tipc_net *tn = net_generic(net, tipc_net_id);
1454         struct tipc_link *l_ptr;
1455         struct tipc_node *n_ptr;
1456         struct tipc_node *found_node = NULL;
1457         int i;
1458
1459         *bearer_id = 0;
1460         rcu_read_lock();
1461         list_for_each_entry_rcu(n_ptr, &tn->node_list, list) {
1462                 tipc_node_lock(n_ptr);
1463                 for (i = 0; i < MAX_BEARERS; i++) {
1464                         l_ptr = n_ptr->links[i].link;
1465                         if (l_ptr && !strcmp(l_ptr->name, link_name)) {
1466                                 *bearer_id = i;
1467                                 found_node = n_ptr;
1468                                 break;
1469                         }
1470                 }
1471                 tipc_node_unlock(n_ptr);
1472                 if (found_node)
1473                         break;
1474         }
1475         rcu_read_unlock();
1476
1477         return found_node;
1478 }
1479
1480 /**
1481  * link_reset_statistics - reset link statistics
1482  * @l_ptr: pointer to link
1483  */
1484 static void link_reset_statistics(struct tipc_link *l_ptr)
1485 {
1486         memset(&l_ptr->stats, 0, sizeof(l_ptr->stats));
1487         l_ptr->stats.sent_info = l_ptr->snd_nxt;
1488         l_ptr->stats.recv_info = l_ptr->rcv_nxt;
1489 }
1490
1491 static void link_print(struct tipc_link *l, const char *str)
1492 {
1493         struct sk_buff *hskb = skb_peek(&l->transmq);
1494         u16 head = hskb ? msg_seqno(buf_msg(hskb)) : l->snd_nxt;
1495         u16 tail = l->snd_nxt - 1;
1496
1497         pr_info("%s Link <%s> state %x\n", str, l->name, l->state);
1498         pr_info("XMTQ: %u [%u-%u], BKLGQ: %u, SNDNX: %u, RCVNX: %u\n",
1499                 skb_queue_len(&l->transmq), head, tail,
1500                 skb_queue_len(&l->backlogq), l->snd_nxt, l->rcv_nxt);
1501 }
1502
1503 /* Parse and validate nested (link) properties valid for media, bearer and link
1504  */
1505 int tipc_nl_parse_link_prop(struct nlattr *prop, struct nlattr *props[])
1506 {
1507         int err;
1508
1509         err = nla_parse_nested(props, TIPC_NLA_PROP_MAX, prop,
1510                                tipc_nl_prop_policy);
1511         if (err)
1512                 return err;
1513
1514         if (props[TIPC_NLA_PROP_PRIO]) {
1515                 u32 prio;
1516
1517                 prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
1518                 if (prio > TIPC_MAX_LINK_PRI)
1519                         return -EINVAL;
1520         }
1521
1522         if (props[TIPC_NLA_PROP_TOL]) {
1523                 u32 tol;
1524
1525                 tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
1526                 if ((tol < TIPC_MIN_LINK_TOL) || (tol > TIPC_MAX_LINK_TOL))
1527                         return -EINVAL;
1528         }
1529
1530         if (props[TIPC_NLA_PROP_WIN]) {
1531                 u32 win;
1532
1533                 win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
1534                 if ((win < TIPC_MIN_LINK_WIN) || (win > TIPC_MAX_LINK_WIN))
1535                         return -EINVAL;
1536         }
1537
1538         return 0;
1539 }
1540
1541 int tipc_nl_link_set(struct sk_buff *skb, struct genl_info *info)
1542 {
1543         int err;
1544         int res = 0;
1545         int bearer_id;
1546         char *name;
1547         struct tipc_link *link;
1548         struct tipc_node *node;
1549         struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
1550         struct net *net = sock_net(skb->sk);
1551
1552         if (!info->attrs[TIPC_NLA_LINK])
1553                 return -EINVAL;
1554
1555         err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
1556                                info->attrs[TIPC_NLA_LINK],
1557                                tipc_nl_link_policy);
1558         if (err)
1559                 return err;
1560
1561         if (!attrs[TIPC_NLA_LINK_NAME])
1562                 return -EINVAL;
1563
1564         name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
1565
1566         if (strcmp(name, tipc_bclink_name) == 0)
1567                 return tipc_nl_bc_link_set(net, attrs);
1568
1569         node = tipc_link_find_owner(net, name, &bearer_id);
1570         if (!node)
1571                 return -EINVAL;
1572
1573         tipc_node_lock(node);
1574
1575         link = node->links[bearer_id].link;
1576         if (!link) {
1577                 res = -EINVAL;
1578                 goto out;
1579         }
1580
1581         if (attrs[TIPC_NLA_LINK_PROP]) {
1582                 struct nlattr *props[TIPC_NLA_PROP_MAX + 1];
1583
1584                 err = tipc_nl_parse_link_prop(attrs[TIPC_NLA_LINK_PROP],
1585                                               props);
1586                 if (err) {
1587                         res = err;
1588                         goto out;
1589                 }
1590
1591                 if (props[TIPC_NLA_PROP_TOL]) {
1592                         u32 tol;
1593
1594                         tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
1595                         link->tolerance = tol;
1596                         tipc_link_proto_xmit(link, STATE_MSG, 0, 0, tol, 0);
1597                 }
1598                 if (props[TIPC_NLA_PROP_PRIO]) {
1599                         u32 prio;
1600
1601                         prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
1602                         link->priority = prio;
1603                         tipc_link_proto_xmit(link, STATE_MSG, 0, 0, 0, prio);
1604                 }
1605                 if (props[TIPC_NLA_PROP_WIN]) {
1606                         u32 win;
1607
1608                         win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
1609                         tipc_link_set_queue_limits(link, win);
1610                 }
1611         }
1612
1613 out:
1614         tipc_node_unlock(node);
1615
1616         return res;
1617 }
1618
1619 static int __tipc_nl_add_stats(struct sk_buff *skb, struct tipc_stats *s)
1620 {
1621         int i;
1622         struct nlattr *stats;
1623
1624         struct nla_map {
1625                 u32 key;
1626                 u32 val;
1627         };
1628
1629         struct nla_map map[] = {
1630                 {TIPC_NLA_STATS_RX_INFO, s->recv_info},
1631                 {TIPC_NLA_STATS_RX_FRAGMENTS, s->recv_fragments},
1632                 {TIPC_NLA_STATS_RX_FRAGMENTED, s->recv_fragmented},
1633                 {TIPC_NLA_STATS_RX_BUNDLES, s->recv_bundles},
1634                 {TIPC_NLA_STATS_RX_BUNDLED, s->recv_bundled},
1635                 {TIPC_NLA_STATS_TX_INFO, s->sent_info},
1636                 {TIPC_NLA_STATS_TX_FRAGMENTS, s->sent_fragments},
1637                 {TIPC_NLA_STATS_TX_FRAGMENTED, s->sent_fragmented},
1638                 {TIPC_NLA_STATS_TX_BUNDLES, s->sent_bundles},
1639                 {TIPC_NLA_STATS_TX_BUNDLED, s->sent_bundled},
1640                 {TIPC_NLA_STATS_MSG_PROF_TOT, (s->msg_length_counts) ?
1641                         s->msg_length_counts : 1},
1642                 {TIPC_NLA_STATS_MSG_LEN_CNT, s->msg_length_counts},
1643                 {TIPC_NLA_STATS_MSG_LEN_TOT, s->msg_lengths_total},
1644                 {TIPC_NLA_STATS_MSG_LEN_P0, s->msg_length_profile[0]},
1645                 {TIPC_NLA_STATS_MSG_LEN_P1, s->msg_length_profile[1]},
1646                 {TIPC_NLA_STATS_MSG_LEN_P2, s->msg_length_profile[2]},
1647                 {TIPC_NLA_STATS_MSG_LEN_P3, s->msg_length_profile[3]},
1648                 {TIPC_NLA_STATS_MSG_LEN_P4, s->msg_length_profile[4]},
1649                 {TIPC_NLA_STATS_MSG_LEN_P5, s->msg_length_profile[5]},
1650                 {TIPC_NLA_STATS_MSG_LEN_P6, s->msg_length_profile[6]},
1651                 {TIPC_NLA_STATS_RX_STATES, s->recv_states},
1652                 {TIPC_NLA_STATS_RX_PROBES, s->recv_probes},
1653                 {TIPC_NLA_STATS_RX_NACKS, s->recv_nacks},
1654                 {TIPC_NLA_STATS_RX_DEFERRED, s->deferred_recv},
1655                 {TIPC_NLA_STATS_TX_STATES, s->sent_states},
1656                 {TIPC_NLA_STATS_TX_PROBES, s->sent_probes},
1657                 {TIPC_NLA_STATS_TX_NACKS, s->sent_nacks},
1658                 {TIPC_NLA_STATS_TX_ACKS, s->sent_acks},
1659                 {TIPC_NLA_STATS_RETRANSMITTED, s->retransmitted},
1660                 {TIPC_NLA_STATS_DUPLICATES, s->duplicates},
1661                 {TIPC_NLA_STATS_LINK_CONGS, s->link_congs},
1662                 {TIPC_NLA_STATS_MAX_QUEUE, s->max_queue_sz},
1663                 {TIPC_NLA_STATS_AVG_QUEUE, s->queue_sz_counts ?
1664                         (s->accu_queue_sz / s->queue_sz_counts) : 0}
1665         };
1666
1667         stats = nla_nest_start(skb, TIPC_NLA_LINK_STATS);
1668         if (!stats)
1669                 return -EMSGSIZE;
1670
1671         for (i = 0; i <  ARRAY_SIZE(map); i++)
1672                 if (nla_put_u32(skb, map[i].key, map[i].val))
1673                         goto msg_full;
1674
1675         nla_nest_end(skb, stats);
1676
1677         return 0;
1678 msg_full:
1679         nla_nest_cancel(skb, stats);
1680
1681         return -EMSGSIZE;
1682 }
1683
1684 /* Caller should hold appropriate locks to protect the link */
1685 static int __tipc_nl_add_link(struct net *net, struct tipc_nl_msg *msg,
1686                               struct tipc_link *link, int nlflags)
1687 {
1688         int err;
1689         void *hdr;
1690         struct nlattr *attrs;
1691         struct nlattr *prop;
1692         struct tipc_net *tn = net_generic(net, tipc_net_id);
1693
1694         hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
1695                           nlflags, TIPC_NL_LINK_GET);
1696         if (!hdr)
1697                 return -EMSGSIZE;
1698
1699         attrs = nla_nest_start(msg->skb, TIPC_NLA_LINK);
1700         if (!attrs)
1701                 goto msg_full;
1702
1703         if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, link->name))
1704                 goto attr_msg_full;
1705         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_DEST,
1706                         tipc_cluster_mask(tn->own_addr)))
1707                 goto attr_msg_full;
1708         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_MTU, link->mtu))
1709                 goto attr_msg_full;
1710         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, link->rcv_nxt))
1711                 goto attr_msg_full;
1712         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, link->snd_nxt))
1713                 goto attr_msg_full;
1714
1715         if (tipc_link_is_up(link))
1716                 if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
1717                         goto attr_msg_full;
1718         if (tipc_link_is_active(link))
1719                 if (nla_put_flag(msg->skb, TIPC_NLA_LINK_ACTIVE))
1720                         goto attr_msg_full;
1721
1722         prop = nla_nest_start(msg->skb, TIPC_NLA_LINK_PROP);
1723         if (!prop)
1724                 goto attr_msg_full;
1725         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
1726                 goto prop_msg_full;
1727         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_TOL, link->tolerance))
1728                 goto prop_msg_full;
1729         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN,
1730                         link->window))
1731                 goto prop_msg_full;
1732         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
1733                 goto prop_msg_full;
1734         nla_nest_end(msg->skb, prop);
1735
1736         err = __tipc_nl_add_stats(msg->skb, &link->stats);
1737         if (err)
1738                 goto attr_msg_full;
1739
1740         nla_nest_end(msg->skb, attrs);
1741         genlmsg_end(msg->skb, hdr);
1742
1743         return 0;
1744
1745 prop_msg_full:
1746         nla_nest_cancel(msg->skb, prop);
1747 attr_msg_full:
1748         nla_nest_cancel(msg->skb, attrs);
1749 msg_full:
1750         genlmsg_cancel(msg->skb, hdr);
1751
1752         return -EMSGSIZE;
1753 }
1754
1755 /* Caller should hold node lock  */
1756 static int __tipc_nl_add_node_links(struct net *net, struct tipc_nl_msg *msg,
1757                                     struct tipc_node *node, u32 *prev_link)
1758 {
1759         u32 i;
1760         int err;
1761
1762         for (i = *prev_link; i < MAX_BEARERS; i++) {
1763                 *prev_link = i;
1764
1765                 if (!node->links[i].link)
1766                         continue;
1767
1768                 err = __tipc_nl_add_link(net, msg,
1769                                          node->links[i].link, NLM_F_MULTI);
1770                 if (err)
1771                         return err;
1772         }
1773         *prev_link = 0;
1774
1775         return 0;
1776 }
1777
1778 int tipc_nl_link_dump(struct sk_buff *skb, struct netlink_callback *cb)
1779 {
1780         struct net *net = sock_net(skb->sk);
1781         struct tipc_net *tn = net_generic(net, tipc_net_id);
1782         struct tipc_node *node;
1783         struct tipc_nl_msg msg;
1784         u32 prev_node = cb->args[0];
1785         u32 prev_link = cb->args[1];
1786         int done = cb->args[2];
1787         int err;
1788
1789         if (done)
1790                 return 0;
1791
1792         msg.skb = skb;
1793         msg.portid = NETLINK_CB(cb->skb).portid;
1794         msg.seq = cb->nlh->nlmsg_seq;
1795
1796         rcu_read_lock();
1797         if (prev_node) {
1798                 node = tipc_node_find(net, prev_node);
1799                 if (!node) {
1800                         /* We never set seq or call nl_dump_check_consistent()
1801                          * this means that setting prev_seq here will cause the
1802                          * consistence check to fail in the netlink callback
1803                          * handler. Resulting in the last NLMSG_DONE message
1804                          * having the NLM_F_DUMP_INTR flag set.
1805                          */
1806                         cb->prev_seq = 1;
1807                         goto out;
1808                 }
1809                 tipc_node_put(node);
1810
1811                 list_for_each_entry_continue_rcu(node, &tn->node_list,
1812                                                  list) {
1813                         tipc_node_lock(node);
1814                         err = __tipc_nl_add_node_links(net, &msg, node,
1815                                                        &prev_link);
1816                         tipc_node_unlock(node);
1817                         if (err)
1818                                 goto out;
1819
1820                         prev_node = node->addr;
1821                 }
1822         } else {
1823                 err = tipc_nl_add_bc_link(net, &msg);
1824                 if (err)
1825                         goto out;
1826
1827                 list_for_each_entry_rcu(node, &tn->node_list, list) {
1828                         tipc_node_lock(node);
1829                         err = __tipc_nl_add_node_links(net, &msg, node,
1830                                                        &prev_link);
1831                         tipc_node_unlock(node);
1832                         if (err)
1833                                 goto out;
1834
1835                         prev_node = node->addr;
1836                 }
1837         }
1838         done = 1;
1839 out:
1840         rcu_read_unlock();
1841
1842         cb->args[0] = prev_node;
1843         cb->args[1] = prev_link;
1844         cb->args[2] = done;
1845
1846         return skb->len;
1847 }
1848
1849 int tipc_nl_link_get(struct sk_buff *skb, struct genl_info *info)
1850 {
1851         struct net *net = genl_info_net(info);
1852         struct tipc_nl_msg msg;
1853         char *name;
1854         int err;
1855
1856         msg.portid = info->snd_portid;
1857         msg.seq = info->snd_seq;
1858
1859         if (!info->attrs[TIPC_NLA_LINK_NAME])
1860                 return -EINVAL;
1861         name = nla_data(info->attrs[TIPC_NLA_LINK_NAME]);
1862
1863         msg.skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
1864         if (!msg.skb)
1865                 return -ENOMEM;
1866
1867         if (strcmp(name, tipc_bclink_name) == 0) {
1868                 err = tipc_nl_add_bc_link(net, &msg);
1869                 if (err) {
1870                         nlmsg_free(msg.skb);
1871                         return err;
1872                 }
1873         } else {
1874                 int bearer_id;
1875                 struct tipc_node *node;
1876                 struct tipc_link *link;
1877
1878                 node = tipc_link_find_owner(net, name, &bearer_id);
1879                 if (!node)
1880                         return -EINVAL;
1881
1882                 tipc_node_lock(node);
1883                 link = node->links[bearer_id].link;
1884                 if (!link) {
1885                         tipc_node_unlock(node);
1886                         nlmsg_free(msg.skb);
1887                         return -EINVAL;
1888                 }
1889
1890                 err = __tipc_nl_add_link(net, &msg, link, 0);
1891                 tipc_node_unlock(node);
1892                 if (err) {
1893                         nlmsg_free(msg.skb);
1894                         return err;
1895                 }
1896         }
1897
1898         return genlmsg_reply(msg.skb, info);
1899 }
1900
1901 int tipc_nl_link_reset_stats(struct sk_buff *skb, struct genl_info *info)
1902 {
1903         int err;
1904         char *link_name;
1905         unsigned int bearer_id;
1906         struct tipc_link *link;
1907         struct tipc_node *node;
1908         struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
1909         struct net *net = sock_net(skb->sk);
1910
1911         if (!info->attrs[TIPC_NLA_LINK])
1912                 return -EINVAL;
1913
1914         err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
1915                                info->attrs[TIPC_NLA_LINK],
1916                                tipc_nl_link_policy);
1917         if (err)
1918                 return err;
1919
1920         if (!attrs[TIPC_NLA_LINK_NAME])
1921                 return -EINVAL;
1922
1923         link_name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
1924
1925         if (strcmp(link_name, tipc_bclink_name) == 0) {
1926                 err = tipc_bclink_reset_stats(net);
1927                 if (err)
1928                         return err;
1929                 return 0;
1930         }
1931
1932         node = tipc_link_find_owner(net, link_name, &bearer_id);
1933         if (!node)
1934                 return -EINVAL;
1935
1936         tipc_node_lock(node);
1937
1938         link = node->links[bearer_id].link;
1939         if (!link) {
1940                 tipc_node_unlock(node);
1941                 return -EINVAL;
1942         }
1943
1944         link_reset_statistics(link);
1945
1946         tipc_node_unlock(node);
1947
1948         return 0;
1949 }