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                 l->owner->inputq = l->inputq;
 563                 l->owner->action_flags |= TIPC_MSG_EVT;
 564         }
 565 }
 566
 567 /**
 568  * tipc_link_reset_fragments - purge link's inbound message fragments queue
 569  * @l_ptr: pointer to link
 570  */
 571 void tipc_link_reset_fragments(struct tipc_link *l_ptr)
 572 {
 573         kfree_skb(l_ptr->reasm_buf);
 574         l_ptr->reasm_buf = NULL;
 575 }
 576
 577 void tipc_link_purge_backlog(struct tipc_link *l)
 578 {
 579         __skb_queue_purge(&l->backlogq);
 580         l->backlog[TIPC_LOW_IMPORTANCE].len = 0;
 581         l->backlog[TIPC_MEDIUM_IMPORTANCE].len = 0;
 582         l->backlog[TIPC_HIGH_IMPORTANCE].len = 0;
 583         l->backlog[TIPC_CRITICAL_IMPORTANCE].len = 0;
 584         l->backlog[TIPC_SYSTEM_IMPORTANCE].len = 0;
 585 }
 586
 587 /**
 588  * tipc_link_purge_queues - purge all pkt queues associated with link
 589  * @l_ptr: pointer to link
 590  */
 591 void tipc_link_purge_queues(struct tipc_link *l_ptr)
 592 {
 593         __skb_queue_purge(&l_ptr->deferdq);
 594         __skb_queue_purge(&l_ptr->transmq);
 595         tipc_link_purge_backlog(l_ptr);
 596         tipc_link_reset_fragments(l_ptr);
 597 }
 598
 599 void tipc_link_reset(struct tipc_link *l)
 600 {
 601         struct tipc_node *owner = l->owner;
 602
 603         tipc_link_fsm_evt(l, LINK_RESET_EVT);
 604
 605         /* Link is down, accept any session */
 606         l->peer_session = WILDCARD_SESSION;
 607
 608         /* If peer is up, it only accepts an incremented session number */
 609         msg_set_session(l->pmsg, msg_session(l->pmsg) + 1);
 610
 611         /* Prepare for renewed mtu size negotiation */
 612         l->mtu = l->advertised_mtu;
 613
 614         /* Clean up all queues, except inputq: */
 615         __skb_queue_purge(&l->transmq);
 616         __skb_queue_purge(&l->deferdq);
 617         if (!owner->inputq)
 618                 owner->inputq = l->inputq;
 619         skb_queue_splice_init(&l->wakeupq, owner->inputq);
 620         if (!skb_queue_empty(owner->inputq))
 621                 owner->action_flags |= TIPC_MSG_EVT;
 622
 623         tipc_link_purge_backlog(l);
 624         kfree_skb(l->reasm_buf);
 625         kfree_skb(l->failover_reasm_skb);
 626         l->reasm_buf = NULL;
 627         l->failover_reasm_skb = NULL;
 628         l->rcv_unacked = 0;
 629         l->snd_nxt = 1;
 630         l->rcv_nxt = 1;
 631         l->silent_intv_cnt = 0;
 632         l->stats.recv_info = 0;
 633         l->stale_count = 0;
 634         link_reset_statistics(l);
 635 }
 636
 637 /**
 638  * __tipc_link_xmit(): same as tipc_link_xmit, but destlink is known & locked
 639  * @link: link to use
 640  * @list: chain of buffers containing message
 641  *
 642  * Consumes the buffer chain, except when returning an error code,
 643  * Returns 0 if success, or errno: -ELINKCONG, -EMSGSIZE or -ENOBUFS
 644  * Messages at TIPC_SYSTEM_IMPORTANCE are always accepted
 645  */
 646 int __tipc_link_xmit(struct net *net, struct tipc_link *link,
 647                      struct sk_buff_head *list)
 648 {
 649         struct tipc_msg *msg = buf_msg(skb_peek(list));
 650         unsigned int maxwin = link->window;
 651         unsigned int i, imp = msg_importance(msg);
 652         uint mtu = link->mtu;
 653         u16 ack = mod(link->rcv_nxt - 1);
 654         u16 seqno = link->snd_nxt;
 655         u16 bc_last_in = link->owner->bclink.last_in;
 656         struct tipc_media_addr *addr = &link->media_addr;
 657         struct sk_buff_head *transmq = &link->transmq;
 658         struct sk_buff_head *backlogq = &link->backlogq;
 659         struct sk_buff *skb, *bskb;
 660
 661         /* Match msg importance against this and all higher backlog limits: */
 662         for (i = imp; i <= TIPC_SYSTEM_IMPORTANCE; i++) {
 663                 if (unlikely(link->backlog[i].len >= link->backlog[i].limit))
 664                         return link_schedule_user(link, list);
 665         }
 666         if (unlikely(msg_size(msg) > mtu))
 667                 return -EMSGSIZE;
 668
 669         /* Prepare each packet for sending, and add to relevant queue: */
 670         while (skb_queue_len(list)) {
 671                 skb = skb_peek(list);
 672                 msg = buf_msg(skb);
 673                 msg_set_seqno(msg, seqno);
 674                 msg_set_ack(msg, ack);
 675                 msg_set_bcast_ack(msg, bc_last_in);
 676
 677                 if (likely(skb_queue_len(transmq) < maxwin)) {
 678                         __skb_dequeue(list);
 679                         __skb_queue_tail(transmq, skb);
 680                         tipc_bearer_send(net, link->bearer_id, skb, addr);
 681                         link->rcv_unacked = 0;
 682                         seqno++;
 683                         continue;
 684                 }
 685                 if (tipc_msg_bundle(skb_peek_tail(backlogq), msg, mtu)) {
 686                         kfree_skb(__skb_dequeue(list));
 687                         link->stats.sent_bundled++;
 688                         continue;
 689                 }
 690                 if (tipc_msg_make_bundle(&bskb, msg, mtu, link->addr)) {
 691                         kfree_skb(__skb_dequeue(list));
 692                         __skb_queue_tail(backlogq, bskb);
 693                         link->backlog[msg_importance(buf_msg(bskb))].len++;
 694                         link->stats.sent_bundled++;
 695                         link->stats.sent_bundles++;
 696                         continue;
 697                 }
 698                 link->backlog[imp].len += skb_queue_len(list);
 699                 skb_queue_splice_tail_init(list, backlogq);
 700         }
 701         link->snd_nxt = seqno;
 702         return 0;
 703 }
 704
 705 /**
 706  * tipc_link_xmit(): enqueue buffer list according to queue situation
 707  * @link: link to use
 708  * @list: chain of buffers containing message
 709  * @xmitq: returned list of packets to be sent by caller
 710  *
 711  * Consumes the buffer chain, except when returning -ELINKCONG,
 712  * since the caller then may want to make more send attempts.
 713  * Returns 0 if success, or errno: -ELINKCONG, -EMSGSIZE or -ENOBUFS
 714  * Messages at TIPC_SYSTEM_IMPORTANCE are always accepted
 715  */
 716 int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *list,
 717                    struct sk_buff_head *xmitq)
 718 {
 719         struct tipc_msg *hdr = buf_msg(skb_peek(list));
 720         unsigned int maxwin = l->window;
 721         unsigned int i, imp = msg_importance(hdr);
 722         unsigned int mtu = l->mtu;
 723         u16 ack = l->rcv_nxt - 1;
 724         u16 seqno = l->snd_nxt;
 725         u16 bc_last_in = l->owner->bclink.last_in;
 726         struct sk_buff_head *transmq = &l->transmq;
 727         struct sk_buff_head *backlogq = &l->backlogq;
 728         struct sk_buff *skb, *_skb, *bskb;
 729
 730         /* Match msg importance against this and all higher backlog limits: */
 731         for (i = imp; i <= TIPC_SYSTEM_IMPORTANCE; i++) {
 732                 if (unlikely(l->backlog[i].len >= l->backlog[i].limit))
 733                         return link_schedule_user(l, list);
 734         }
 735         if (unlikely(msg_size(hdr) > mtu))
 736                 return -EMSGSIZE;
 737
 738         /* Prepare each packet for sending, and add to relevant queue: */
 739         while (skb_queue_len(list)) {
 740                 skb = skb_peek(list);
 741                 hdr = buf_msg(skb);
 742                 msg_set_seqno(hdr, seqno);
 743                 msg_set_ack(hdr, ack);
 744                 msg_set_bcast_ack(hdr, bc_last_in);
 745
 746                 if (likely(skb_queue_len(transmq) < maxwin)) {
 747                         _skb = skb_clone(skb, GFP_ATOMIC);
 748                         if (!_skb)
 749                                 return -ENOBUFS;
 750                         __skb_dequeue(list);
 751                         __skb_queue_tail(transmq, skb);
 752                         __skb_queue_tail(xmitq, _skb);
 753                         l->rcv_unacked = 0;
 754                         seqno++;
 755                         continue;
 756                 }
 757                 if (tipc_msg_bundle(skb_peek_tail(backlogq), hdr, mtu)) {
 758                         kfree_skb(__skb_dequeue(list));
 759                         l->stats.sent_bundled++;
 760                         continue;
 761                 }
 762                 if (tipc_msg_make_bundle(&bskb, hdr, mtu, l->addr)) {
 763                         kfree_skb(__skb_dequeue(list));
 764                         __skb_queue_tail(backlogq, bskb);
 765                         l->backlog[msg_importance(buf_msg(bskb))].len++;
 766                         l->stats.sent_bundled++;
 767                         l->stats.sent_bundles++;
 768                         continue;
 769                 }
 770                 l->backlog[imp].len += skb_queue_len(list);
 771                 skb_queue_splice_tail_init(list, backlogq);
 772         }
 773         l->snd_nxt = seqno;
 774         return 0;
 775 }
 776
 777 /*
 778  * tipc_link_sync_rcv - synchronize broadcast link endpoints.
 779  * Receive the sequence number where we should start receiving and
 780  * acking broadcast packets from a newly added peer node, and open
 781  * up for reception of such packets.
 782  *
 783  * Called with node locked
 784  */
 785 static void tipc_link_sync_rcv(struct tipc_node *n, struct sk_buff *buf)
 786 {
 787         struct tipc_msg *msg = buf_msg(buf);
 788
 789         n->bclink.last_sent = n->bclink.last_in = msg_last_bcast(msg);
 790         n->bclink.recv_permitted = true;
 791         kfree_skb(buf);
 792 }
 793
 794 /*
 795  * tipc_link_push_packets - push unsent packets to bearer
 796  *
 797  * Push out the unsent messages of a link where congestion
 798  * has abated. Node is locked.
 799  *
 800  * Called with node locked
 801  */
 802 void tipc_link_push_packets(struct tipc_link *link)
 803 {
 804         struct sk_buff *skb;
 805         struct tipc_msg *msg;
 806         u16 seqno = link->snd_nxt;
 807         u16 ack = mod(link->rcv_nxt - 1);
 808
 809         while (skb_queue_len(&link->transmq) < link->window) {
 810                 skb = __skb_dequeue(&link->backlogq);
 811                 if (!skb)
 812                         break;
 813                 msg = buf_msg(skb);
 814                 link->backlog[msg_importance(msg)].len--;
 815                 msg_set_ack(msg, ack);
 816                 msg_set_seqno(msg, seqno);
 817                 seqno = mod(seqno + 1);
 818                 msg_set_bcast_ack(msg, link->owner->bclink.last_in);
 819                 link->rcv_unacked = 0;
 820                 __skb_queue_tail(&link->transmq, skb);
 821                 tipc_bearer_send(link->owner->net, link->bearer_id,
 822                                  skb, &link->media_addr);
 823         }
 824         link->snd_nxt = seqno;
 825 }
 826
 827 void tipc_link_advance_backlog(struct tipc_link *l, struct sk_buff_head *xmitq)
 828 {
 829         struct sk_buff *skb, *_skb;
 830         struct tipc_msg *hdr;
 831         u16 seqno = l->snd_nxt;
 832         u16 ack = l->rcv_nxt - 1;
 833
 834         while (skb_queue_len(&l->transmq) < l->window) {
 835                 skb = skb_peek(&l->backlogq);
 836                 if (!skb)
 837                         break;
 838                 _skb = skb_clone(skb, GFP_ATOMIC);
 839                 if (!_skb)
 840                         break;
 841                 __skb_dequeue(&l->backlogq);
 842                 hdr = buf_msg(skb);
 843                 l->backlog[msg_importance(hdr)].len--;
 844                 __skb_queue_tail(&l->transmq, skb);
 845                 __skb_queue_tail(xmitq, _skb);
 846                 msg_set_ack(hdr, ack);
 847                 msg_set_seqno(hdr, seqno);
 848                 msg_set_bcast_ack(hdr, l->owner->bclink.last_in);
 849                 l->rcv_unacked = 0;
 850                 seqno++;
 851         }
 852         l->snd_nxt = seqno;
 853 }
 854
 855 static void link_retransmit_failure(struct tipc_link *l_ptr,
 856                                     struct sk_buff *buf)
 857 {
 858         struct tipc_msg *msg = buf_msg(buf);
 859         struct net *net = l_ptr->owner->net;
 860
 861         pr_warn("Retransmission failure on link <%s>\n", l_ptr->name);
 862
 863         if (l_ptr->addr) {
 864                 /* Handle failure on standard link */
 865                 link_print(l_ptr, "Resetting link ");
 866                 pr_info("Failed msg: usr %u, typ %u, len %u, err %u\n",
 867                         msg_user(msg), msg_type(msg), msg_size(msg),
 868                         msg_errcode(msg));
 869                 pr_info("sqno %u, prev: %x, src: %x\n",
 870                         msg_seqno(msg), msg_prevnode(msg), msg_orignode(msg));
 871         } else {
 872                 /* Handle failure on broadcast link */
 873                 struct tipc_node *n_ptr;
 874                 char addr_string[16];
 875
 876                 pr_info("Msg seq number: %u,  ", msg_seqno(msg));
 877                 pr_cont("Outstanding acks: %lu\n",
 878                         (unsigned long) TIPC_SKB_CB(buf)->handle);
 879
 880                 n_ptr = tipc_bclink_retransmit_to(net);
 881
 882                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 883                 pr_info("Broadcast link info for %s\n", addr_string);
 884                 pr_info("Reception permitted: %d,  Acked: %u\n",
 885                         n_ptr->bclink.recv_permitted,
 886                         n_ptr->bclink.acked);
 887                 pr_info("Last in: %u,  Oos state: %u,  Last sent: %u\n",
 888                         n_ptr->bclink.last_in,
 889                         n_ptr->bclink.oos_state,
 890                         n_ptr->bclink.last_sent);
 891
 892                 n_ptr->action_flags |= TIPC_BCAST_RESET;
 893                 l_ptr->stale_count = 0;
 894         }
 895 }
 896
 897 void tipc_link_retransmit(struct tipc_link *l_ptr, struct sk_buff *skb,
 898                           u32 retransmits)
 899 {
 900         struct tipc_msg *msg;
 901
 902         if (!skb)
 903                 return;
 904
 905         msg = buf_msg(skb);
 906
 907         /* Detect repeated retransmit failures */
 908         if (l_ptr->last_retransm == msg_seqno(msg)) {
 909                 if (++l_ptr->stale_count > 100) {
 910                         link_retransmit_failure(l_ptr, skb);
 911                         return;
 912                 }
 913         } else {
 914                 l_ptr->last_retransm = msg_seqno(msg);
 915                 l_ptr->stale_count = 1;
 916         }
 917
 918         skb_queue_walk_from(&l_ptr->transmq, skb) {
 919                 if (!retransmits)
 920                         break;
 921                 msg = buf_msg(skb);
 922                 msg_set_ack(msg, mod(l_ptr->rcv_nxt - 1));
 923                 msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
 924                 tipc_bearer_send(l_ptr->owner->net, l_ptr->bearer_id, skb,
 925                                  &l_ptr->media_addr);
 926                 retransmits--;
 927                 l_ptr->stats.retransmitted++;
 928         }
 929 }
 930
 931 static int tipc_link_retransm(struct tipc_link *l, int retransm,
 932                               struct sk_buff_head *xmitq)
 933 {
 934         struct sk_buff *_skb, *skb = skb_peek(&l->transmq);
 935         struct tipc_msg *hdr;
 936
 937         if (!skb)
 938                 return 0;
 939
 940         /* Detect repeated retransmit failures on same packet */
 941         if (likely(l->last_retransm != buf_seqno(skb))) {
 942                 l->last_retransm = buf_seqno(skb);
 943                 l->stale_count = 1;
 944         } else if (++l->stale_count > 100) {
 945                 link_retransmit_failure(l, skb);
 946                 return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
 947         }
 948         skb_queue_walk(&l->transmq, skb) {
 949                 if (!retransm)
 950                         return 0;
 951                 hdr = buf_msg(skb);
 952                 _skb = __pskb_copy(skb, MIN_H_SIZE, GFP_ATOMIC);
 953                 if (!_skb)
 954                         return 0;
 955                 hdr = buf_msg(_skb);
 956                 msg_set_ack(hdr, l->rcv_nxt - 1);
 957                 msg_set_bcast_ack(hdr, l->owner->bclink.last_in);
 958                 _skb->priority = TC_PRIO_CONTROL;
 959                 __skb_queue_tail(xmitq, _skb);
 960                 retransm--;
 961                 l->stats.retransmitted++;
 962         }
 963         return 0;
 964 }
 965
 966 /* tipc_data_input - deliver data and name distr msgs to upper layer
 967  *
 968  * Consumes buffer if message is of right type
 969  * Node lock must be held
 970  */
 971 static bool tipc_data_input(struct tipc_link *link, struct sk_buff *skb)
 972 {
 973         struct tipc_node *node = link->owner;
 974         struct tipc_msg *msg = buf_msg(skb);
 975         u32 dport = msg_destport(msg);
 976
 977         switch (msg_user(msg)) {
 978         case TIPC_LOW_IMPORTANCE:
 979         case TIPC_MEDIUM_IMPORTANCE:
 980         case TIPC_HIGH_IMPORTANCE:
 981         case TIPC_CRITICAL_IMPORTANCE:
 982         case CONN_MANAGER:
 983                 if (tipc_skb_queue_tail(link->inputq, skb, dport)) {
 984                         node->inputq = link->inputq;
 985                         node->action_flags |= TIPC_MSG_EVT;
 986                 }
 987                 return true;
 988         case NAME_DISTRIBUTOR:
 989                 node->bclink.recv_permitted = true;
 990                 node->namedq = link->namedq;
 991                 skb_queue_tail(link->namedq, skb);
 992                 if (skb_queue_len(link->namedq) == 1)
 993                         node->action_flags |= TIPC_NAMED_MSG_EVT;
 994                 return true;
 995         case MSG_BUNDLER:
 996         case TUNNEL_PROTOCOL:
 997         case MSG_FRAGMENTER:
 998         case BCAST_PROTOCOL:
 999                 return false;
1000         default:
1001                 pr_warn("Dropping received illegal msg type\n");
1002                 kfree_skb(skb);
1003                 return false;
1004         };
1005 }
1006
1007 /* tipc_link_input - process packet that has passed link protocol check
1008  *
1009  * Consumes buffer
1010  */
1011 static int tipc_link_input(struct tipc_link *l, struct sk_buff *skb)
1012 {
1013         struct tipc_node *node = l->owner;
1014         struct tipc_msg *hdr = buf_msg(skb);
1015         struct sk_buff **reasm_skb = &l->reasm_buf;
1016         struct sk_buff *iskb;
1017         int usr = msg_user(hdr);
1018         int rc = 0;
1019         int pos = 0;
1020         int ipos = 0;
1021
1022         if (unlikely(usr == TUNNEL_PROTOCOL)) {
1023                 if (msg_type(hdr) == SYNCH_MSG) {
1024                         __skb_queue_purge(&l->deferdq);
1025                         goto drop;
1026                 }
1027                 if (!tipc_msg_extract(skb, &iskb, &ipos))
1028                         return rc;
1029                 kfree_skb(skb);
1030                 skb = iskb;
1031                 hdr = buf_msg(skb);
1032                 if (less(msg_seqno(hdr), l->drop_point))
1033                         goto drop;
1034                 if (tipc_data_input(l, skb))
1035                         return rc;
1036                 usr = msg_user(hdr);
1037                 reasm_skb = &l->failover_reasm_skb;
1038         }
1039
1040         if (usr == MSG_BUNDLER) {
1041                 l->stats.recv_bundles++;
1042                 l->stats.recv_bundled += msg_msgcnt(hdr);
1043                 while (tipc_msg_extract(skb, &iskb, &pos))
1044                         tipc_data_input(l, iskb);
1045                 return 0;
1046         } else if (usr == MSG_FRAGMENTER) {
1047                 l->stats.recv_fragments++;
1048                 if (tipc_buf_append(reasm_skb, &skb)) {
1049                         l->stats.recv_fragmented++;
1050                         tipc_data_input(l, skb);
1051                 } else if (!*reasm_skb) {
1052                         return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1053                 }
1054                 return 0;
1055         } else if (usr == BCAST_PROTOCOL) {
1056                 tipc_link_sync_rcv(node, skb);
1057                 return 0;
1058         }
1059 drop:
1060         kfree_skb(skb);
1061         return 0;
1062 }
1063
1064 static bool tipc_link_release_pkts(struct tipc_link *l, u16 acked)
1065 {
1066         bool released = false;
1067         struct sk_buff *skb, *tmp;
1068
1069         skb_queue_walk_safe(&l->transmq, skb, tmp) {
1070                 if (more(buf_seqno(skb), acked))
1071                         break;
1072                 __skb_unlink(skb, &l->transmq);
1073                 kfree_skb(skb);
1074                 released = true;
1075         }
1076         return released;
1077 }
1078
1079 /* tipc_link_rcv - process TIPC packets/messages arriving from off-node
1080  * @link: the link that should handle the message
1081  * @skb: TIPC packet
1082  * @xmitq: queue to place packets to be sent after this call
1083  */
1084 int tipc_link_rcv(struct tipc_link *l, struct sk_buff *skb,
1085                   struct sk_buff_head *xmitq)
1086 {
1087         struct sk_buff_head *arrvq = &l->deferdq;
1088         struct tipc_msg *hdr;
1089         u16 seqno, rcv_nxt;
1090         int rc = 0;
1091
1092         if (unlikely(!__tipc_skb_queue_sorted(arrvq, skb))) {
1093                 if (!(skb_queue_len(arrvq) % TIPC_NACK_INTV))
1094                         tipc_link_build_proto_msg(l, STATE_MSG, 0,
1095                                                   0, 0, 0, xmitq);
1096                 return rc;
1097         }
1098
1099         while ((skb = skb_peek(arrvq))) {
1100                 hdr = buf_msg(skb);
1101
1102                 /* Verify and update link state */
1103                 if (unlikely(msg_user(hdr) == LINK_PROTOCOL)) {
1104                         __skb_dequeue(arrvq);
1105                         rc = tipc_link_proto_rcv(l, skb, xmitq);
1106                         continue;
1107                 }
1108
1109                 if (unlikely(!link_is_up(l))) {
1110                         rc = tipc_link_fsm_evt(l, LINK_ESTABLISH_EVT);
1111                         if (!link_is_up(l)) {
1112                                 kfree_skb(__skb_dequeue(arrvq));
1113                                 return rc;
1114                         }
1115                 }
1116
1117                 l->silent_intv_cnt = 0;
1118
1119                 /* Forward queues and wake up waiting users */
1120                 if (likely(tipc_link_release_pkts(l, msg_ack(hdr)))) {
1121                         tipc_link_advance_backlog(l, xmitq);
1122                         if (unlikely(!skb_queue_empty(&l->wakeupq)))
1123                                 link_prepare_wakeup(l);
1124                 }
1125
1126                 /* Defer reception if there is a gap in the sequence */
1127                 seqno = msg_seqno(hdr);
1128                 rcv_nxt = l->rcv_nxt;
1129                 if (unlikely(less(rcv_nxt, seqno))) {
1130                         l->stats.deferred_recv++;
1131                         return rc;
1132                 }
1133
1134                 __skb_dequeue(arrvq);
1135
1136                 /* Drop if packet already received */
1137                 if (unlikely(more(rcv_nxt, seqno))) {
1138                         l->stats.duplicates++;
1139                         kfree_skb(skb);
1140                         return rc;
1141                 }
1142
1143                 /* Packet can be delivered */
1144                 l->rcv_nxt++;
1145                 l->stats.recv_info++;
1146                 if (unlikely(!tipc_data_input(l, skb)))
1147                         rc = tipc_link_input(l, skb);
1148
1149                 /* Ack at regular intervals */
1150                 if (unlikely(++l->rcv_unacked >= TIPC_MIN_LINK_WIN)) {
1151                         l->rcv_unacked = 0;
1152                         l->stats.sent_acks++;
1153                         tipc_link_build_proto_msg(l, STATE_MSG,
1154                                                   0, 0, 0, 0, xmitq);
1155                 }
1156         }
1157         return rc;
1158 }
1159
1160 /**
1161  * tipc_link_defer_pkt - Add out-of-sequence message to deferred reception queue
1162  *
1163  * Returns increase in queue length (i.e. 0 or 1)
1164  */
1165 u32 tipc_link_defer_pkt(struct sk_buff_head *list, struct sk_buff *skb)
1166 {
1167         struct sk_buff *skb1;
1168         u16 seq_no = buf_seqno(skb);
1169
1170         /* Empty queue ? */
1171         if (skb_queue_empty(list)) {
1172                 __skb_queue_tail(list, skb);
1173                 return 1;
1174         }
1175
1176         /* Last ? */
1177         if (less(buf_seqno(skb_peek_tail(list)), seq_no)) {
1178                 __skb_queue_tail(list, skb);
1179                 return 1;
1180         }
1181
1182         /* Locate insertion point in queue, then insert; discard if duplicate */
1183         skb_queue_walk(list, skb1) {
1184                 u16 curr_seqno = buf_seqno(skb1);
1185
1186                 if (seq_no == curr_seqno) {
1187                         kfree_skb(skb);
1188                         return 0;
1189                 }
1190
1191                 if (less(seq_no, curr_seqno))
1192                         break;
1193         }
1194
1195         __skb_queue_before(list, skb1, skb);
1196         return 1;
1197 }
1198
1199 /*
1200  * Send protocol message to the other endpoint.
1201  */
1202 void tipc_link_proto_xmit(struct tipc_link *l, u32 msg_typ, int probe_msg,
1203                           u32 gap, u32 tolerance, u32 priority)
1204 {
1205         struct sk_buff *skb = NULL;
1206         struct sk_buff_head xmitq;
1207
1208         __skb_queue_head_init(&xmitq);
1209         tipc_link_build_proto_msg(l, msg_typ, probe_msg, gap,
1210                                   tolerance, priority, &xmitq);
1211         skb = __skb_dequeue(&xmitq);
1212         if (!skb)
1213                 return;
1214         tipc_bearer_send(l->owner->net, l->bearer_id, skb, &l->media_addr);
1215         l->rcv_unacked = 0;
1216         kfree_skb(skb);
1217 }
1218
1219 /* tipc_link_build_proto_msg: prepare link protocol message for transmission
1220  */
1221 static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
1222                                       u16 rcvgap, int tolerance, int priority,
1223                                       struct sk_buff_head *xmitq)
1224 {
1225         struct sk_buff *skb = NULL;
1226         struct tipc_msg *hdr = l->pmsg;
1227         u16 snd_nxt = l->snd_nxt;
1228         u16 rcv_nxt = l->rcv_nxt;
1229         u16 rcv_last = rcv_nxt - 1;
1230         int node_up = l->owner->bclink.recv_permitted;
1231
1232         /* Don't send protocol message during reset or link failover */
1233         if (tipc_link_is_blocked(l))
1234                 return;
1235
1236         msg_set_type(hdr, mtyp);
1237         msg_set_net_plane(hdr, l->net_plane);
1238         msg_set_bcast_ack(hdr, l->owner->bclink.last_in);
1239         msg_set_last_bcast(hdr, tipc_bclink_get_last_sent(l->owner->net));
1240         msg_set_link_tolerance(hdr, tolerance);
1241         msg_set_linkprio(hdr, priority);
1242         msg_set_redundant_link(hdr, node_up);
1243         msg_set_seq_gap(hdr, 0);
1244
1245         /* Compatibility: created msg must not be in sequence with pkt flow */
1246         msg_set_seqno(hdr, snd_nxt + U16_MAX / 2);
1247
1248         if (mtyp == STATE_MSG) {
1249                 if (!tipc_link_is_up(l))
1250                         return;
1251                 msg_set_next_sent(hdr, snd_nxt);
1252
1253                 /* Override rcvgap if there are packets in deferred queue */
1254                 if (!skb_queue_empty(&l->deferdq))
1255                         rcvgap = buf_seqno(skb_peek(&l->deferdq)) - rcv_nxt;
1256                 if (rcvgap) {
1257                         msg_set_seq_gap(hdr, rcvgap);
1258                         l->stats.sent_nacks++;
1259                 }
1260                 msg_set_ack(hdr, rcv_last);
1261                 msg_set_probe(hdr, probe);
1262                 if (probe)
1263                         l->stats.sent_probes++;
1264                 l->stats.sent_states++;
1265         } else {
1266                 /* RESET_MSG or ACTIVATE_MSG */
1267                 msg_set_max_pkt(hdr, l->advertised_mtu);
1268                 msg_set_ack(hdr, l->rcv_nxt - 1);
1269                 msg_set_next_sent(hdr, 1);
1270         }
1271         skb = tipc_buf_acquire(msg_size(hdr));
1272         if (!skb)
1273                 return;
1274         skb_copy_to_linear_data(skb, hdr, msg_size(hdr));
1275         skb->priority = TC_PRIO_CONTROL;
1276         __skb_queue_tail(xmitq, skb);
1277 }
1278
1279 /* tipc_link_tnl_prepare(): prepare and return a list of tunnel packets
1280  * with contents of the link's tranmsit and backlog queues.
1281  */
1282 void tipc_link_tnl_prepare(struct tipc_link *l, struct tipc_link *tnl,
1283                            int mtyp, struct sk_buff_head *xmitq)
1284 {
1285         struct sk_buff *skb, *tnlskb;
1286         struct tipc_msg *hdr, tnlhdr;
1287         struct sk_buff_head *queue = &l->transmq;
1288         struct sk_buff_head tmpxq, tnlq;
1289         u16 pktlen, pktcnt, seqno = l->snd_nxt;
1290
1291         if (!tnl)
1292                 return;
1293
1294         skb_queue_head_init(&tnlq);
1295         skb_queue_head_init(&tmpxq);
1296
1297         /* At least one packet required for safe algorithm => add dummy */
1298         skb = tipc_msg_create(TIPC_LOW_IMPORTANCE, TIPC_DIRECT_MSG,
1299                               BASIC_H_SIZE, 0, l->addr, link_own_addr(l),
1300                               0, 0, TIPC_ERR_NO_PORT);
1301         if (!skb) {
1302                 pr_warn("%sunable to create tunnel packet\n", link_co_err);
1303                 return;
1304         }
1305         skb_queue_tail(&tnlq, skb);
1306         tipc_link_xmit(l, &tnlq, &tmpxq);
1307         __skb_queue_purge(&tmpxq);
1308
1309         /* Initialize reusable tunnel packet header */
1310         tipc_msg_init(link_own_addr(l), &tnlhdr, TUNNEL_PROTOCOL,
1311                       mtyp, INT_H_SIZE, l->addr);
1312         pktcnt = skb_queue_len(&l->transmq) + skb_queue_len(&l->backlogq);
1313         msg_set_msgcnt(&tnlhdr, pktcnt);
1314         msg_set_bearer_id(&tnlhdr, l->peer_bearer_id);
1315 tnl:
1316         /* Wrap each packet into a tunnel packet */
1317         skb_queue_walk(queue, skb) {
1318                 hdr = buf_msg(skb);
1319                 if (queue == &l->backlogq)
1320                         msg_set_seqno(hdr, seqno++);
1321                 pktlen = msg_size(hdr);
1322                 msg_set_size(&tnlhdr, pktlen + INT_H_SIZE);
1323                 tnlskb = tipc_buf_acquire(pktlen + INT_H_SIZE);
1324                 if (!tnlskb) {
1325                         pr_warn("%sunable to send packet\n", link_co_err);
1326                         return;
1327                 }
1328                 skb_copy_to_linear_data(tnlskb, &tnlhdr, INT_H_SIZE);
1329                 skb_copy_to_linear_data_offset(tnlskb, INT_H_SIZE, hdr, pktlen);
1330                 __skb_queue_tail(&tnlq, tnlskb);
1331         }
1332         if (queue != &l->backlogq) {
1333                 queue = &l->backlogq;
1334                 goto tnl;
1335         }
1336
1337         tipc_link_xmit(tnl, &tnlq, xmitq);
1338
1339         if (mtyp == FAILOVER_MSG) {
1340                 tnl->drop_point = l->rcv_nxt;
1341                 tnl->failover_reasm_skb = l->reasm_buf;
1342                 l->reasm_buf = NULL;
1343         }
1344 }
1345
1346 /* tipc_link_proto_rcv(): receive link level protocol message :
1347  * Note that network plane id propagates through the network, and may
1348  * change at any time. The node with lowest numerical id determines
1349  * network plane
1350  */
1351 static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
1352                                struct sk_buff_head *xmitq)
1353 {
1354         struct tipc_msg *hdr = buf_msg(skb);
1355         u16 rcvgap = 0;
1356         u16 nacked_gap = msg_seq_gap(hdr);
1357         u16 peers_snd_nxt =  msg_next_sent(hdr);
1358         u16 peers_tol = msg_link_tolerance(hdr);
1359         u16 peers_prio = msg_linkprio(hdr);
1360         char *if_name;
1361         int rc = 0;
1362
1363         if (tipc_link_is_blocked(l))
1364                 goto exit;
1365
1366         if (link_own_addr(l) > msg_prevnode(hdr))
1367                 l->net_plane = msg_net_plane(hdr);
1368
1369         switch (msg_type(hdr)) {
1370         case RESET_MSG:
1371
1372                 /* Ignore duplicate RESET with old session number */
1373                 if ((less_eq(msg_session(hdr), l->peer_session)) &&
1374                     (l->peer_session != WILDCARD_SESSION))
1375                         break;
1376                 /* fall thru' */
1377
1378         case ACTIVATE_MSG:
1379
1380                 /* Complete own link name with peer's interface name */
1381                 if_name =  strrchr(l->name, ':') + 1;
1382                 if (sizeof(l->name) - (if_name - l->name) <= TIPC_MAX_IF_NAME)
1383                         break;
1384                 if (msg_data_sz(hdr) < TIPC_MAX_IF_NAME)
1385                         break;
1386                 strncpy(if_name, msg_data(hdr), TIPC_MAX_IF_NAME);
1387
1388                 /* Update own tolerance if peer indicates a non-zero value */
1389                 if (in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL))
1390                         l->tolerance = peers_tol;
1391
1392                 /* Update own priority if peer's priority is higher */
1393                 if (in_range(peers_prio, l->priority + 1, TIPC_MAX_LINK_PRI))
1394                         l->priority = peers_prio;
1395
1396                 if (msg_type(hdr) == RESET_MSG) {
1397                         rc |= tipc_link_fsm_evt(l, LINK_PEER_RESET_EVT);
1398                 } else if (!link_is_up(l)) {
1399                         tipc_link_fsm_evt(l, LINK_PEER_RESET_EVT);
1400                         rc |= tipc_link_fsm_evt(l, LINK_ESTABLISH_EVT);
1401                 }
1402                 l->peer_session = msg_session(hdr);
1403                 l->peer_bearer_id = msg_bearer_id(hdr);
1404                 if (l->mtu > msg_max_pkt(hdr))
1405                         l->mtu = msg_max_pkt(hdr);
1406                 break;
1407
1408         case STATE_MSG:
1409
1410                 /* Update own tolerance if peer indicates a non-zero value */
1411                 if (in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL))
1412                         l->tolerance = peers_tol;
1413
1414                 l->silent_intv_cnt = 0;
1415                 l->stats.recv_states++;
1416                 if (msg_probe(hdr))
1417                         l->stats.recv_probes++;
1418                 rc = tipc_link_fsm_evt(l, LINK_ESTABLISH_EVT);
1419                 if (!link_is_up(l))
1420                         break;
1421
1422                 /* Send NACK if peer has sent pkts we haven't received yet */
1423                 if (more(peers_snd_nxt, l->rcv_nxt))
1424                         rcvgap = peers_snd_nxt - l->rcv_nxt;
1425                 if (rcvgap || (msg_probe(hdr)))
1426                         tipc_link_build_proto_msg(l, STATE_MSG, 0, rcvgap,
1427                                                   0, 0, xmitq);
1428                 tipc_link_release_pkts(l, msg_ack(hdr));
1429
1430                 /* If NACK, retransmit will now start at right position */
1431                 if (nacked_gap) {
1432                         rc = tipc_link_retransm(l, nacked_gap, xmitq);
1433                         l->stats.recv_nacks++;
1434                 }
1435
1436                 tipc_link_advance_backlog(l, xmitq);
1437                 if (unlikely(!skb_queue_empty(&l->wakeupq)))
1438                         link_prepare_wakeup(l);
1439         }
1440 exit:
1441         kfree_skb(skb);
1442         return rc;
1443 }
1444
1445 void tipc_link_set_queue_limits(struct tipc_link *l, u32 win)
1446 {
1447         int max_bulk = TIPC_MAX_PUBLICATIONS / (l->mtu / ITEM_SIZE);
1448
1449         l->window = win;
1450         l->backlog[TIPC_LOW_IMPORTANCE].limit      = win / 2;
1451         l->backlog[TIPC_MEDIUM_IMPORTANCE].limit   = win;
1452         l->backlog[TIPC_HIGH_IMPORTANCE].limit     = win / 2 * 3;
1453         l->backlog[TIPC_CRITICAL_IMPORTANCE].limit = win * 2;
1454         l->backlog[TIPC_SYSTEM_IMPORTANCE].limit   = max_bulk;
1455 }
1456
1457 /* tipc_link_find_owner - locate owner node of link by link's name
1458  * @net: the applicable net namespace
1459  * @name: pointer to link name string
1460  * @bearer_id: pointer to index in 'node->links' array where the link was found.
1461  *
1462  * Returns pointer to node owning the link, or 0 if no matching link is found.
1463  */
1464 static struct tipc_node *tipc_link_find_owner(struct net *net,
1465                                               const char *link_name,
1466                                               unsigned int *bearer_id)
1467 {
1468         struct tipc_net *tn = net_generic(net, tipc_net_id);
1469         struct tipc_link *l_ptr;
1470         struct tipc_node *n_ptr;
1471         struct tipc_node *found_node = NULL;
1472         int i;
1473
1474         *bearer_id = 0;
1475         rcu_read_lock();
1476         list_for_each_entry_rcu(n_ptr, &tn->node_list, list) {
1477                 tipc_node_lock(n_ptr);
1478                 for (i = 0; i < MAX_BEARERS; i++) {
1479                         l_ptr = n_ptr->links[i].link;
1480                         if (l_ptr && !strcmp(l_ptr->name, link_name)) {
1481                                 *bearer_id = i;
1482                                 found_node = n_ptr;
1483                                 break;
1484                         }
1485                 }
1486                 tipc_node_unlock(n_ptr);
1487                 if (found_node)
1488                         break;
1489         }
1490         rcu_read_unlock();
1491
1492         return found_node;
1493 }
1494
1495 /**
1496  * link_reset_statistics - reset link statistics
1497  * @l_ptr: pointer to link
1498  */
1499 static void link_reset_statistics(struct tipc_link *l_ptr)
1500 {
1501         memset(&l_ptr->stats, 0, sizeof(l_ptr->stats));
1502         l_ptr->stats.sent_info = l_ptr->snd_nxt;
1503         l_ptr->stats.recv_info = l_ptr->rcv_nxt;
1504 }
1505
1506 static void link_print(struct tipc_link *l, const char *str)
1507 {
1508         struct sk_buff *hskb = skb_peek(&l->transmq);
1509         u16 head = hskb ? msg_seqno(buf_msg(hskb)) : l->snd_nxt;
1510         u16 tail = l->snd_nxt - 1;
1511
1512         pr_info("%s Link <%s> state %x\n", str, l->name, l->state);
1513         pr_info("XMTQ: %u [%u-%u], BKLGQ: %u, SNDNX: %u, RCVNX: %u\n",
1514                 skb_queue_len(&l->transmq), head, tail,
1515                 skb_queue_len(&l->backlogq), l->snd_nxt, l->rcv_nxt);
1516 }
1517
1518 /* Parse and validate nested (link) properties valid for media, bearer and link
1519  */
1520 int tipc_nl_parse_link_prop(struct nlattr *prop, struct nlattr *props[])
1521 {
1522         int err;
1523
1524         err = nla_parse_nested(props, TIPC_NLA_PROP_MAX, prop,
1525                                tipc_nl_prop_policy);
1526         if (err)
1527                 return err;
1528
1529         if (props[TIPC_NLA_PROP_PRIO]) {
1530                 u32 prio;
1531
1532                 prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
1533                 if (prio > TIPC_MAX_LINK_PRI)
1534                         return -EINVAL;
1535         }
1536
1537         if (props[TIPC_NLA_PROP_TOL]) {
1538                 u32 tol;
1539
1540                 tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
1541                 if ((tol < TIPC_MIN_LINK_TOL) || (tol > TIPC_MAX_LINK_TOL))
1542                         return -EINVAL;
1543         }
1544
1545         if (props[TIPC_NLA_PROP_WIN]) {
1546                 u32 win;
1547
1548                 win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
1549                 if ((win < TIPC_MIN_LINK_WIN) || (win > TIPC_MAX_LINK_WIN))
1550                         return -EINVAL;
1551         }
1552
1553         return 0;
1554 }
1555
1556 int tipc_nl_link_set(struct sk_buff *skb, struct genl_info *info)
1557 {
1558         int err;
1559         int res = 0;
1560         int bearer_id;
1561         char *name;
1562         struct tipc_link *link;
1563         struct tipc_node *node;
1564         struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
1565         struct net *net = sock_net(skb->sk);
1566
1567         if (!info->attrs[TIPC_NLA_LINK])
1568                 return -EINVAL;
1569
1570         err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
1571                                info->attrs[TIPC_NLA_LINK],
1572                                tipc_nl_link_policy);
1573         if (err)
1574                 return err;
1575
1576         if (!attrs[TIPC_NLA_LINK_NAME])
1577                 return -EINVAL;
1578
1579         name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
1580
1581         if (strcmp(name, tipc_bclink_name) == 0)
1582                 return tipc_nl_bc_link_set(net, attrs);
1583
1584         node = tipc_link_find_owner(net, name, &bearer_id);
1585         if (!node)
1586                 return -EINVAL;
1587
1588         tipc_node_lock(node);
1589
1590         link = node->links[bearer_id].link;
1591         if (!link) {
1592                 res = -EINVAL;
1593                 goto out;
1594         }
1595
1596         if (attrs[TIPC_NLA_LINK_PROP]) {
1597                 struct nlattr *props[TIPC_NLA_PROP_MAX + 1];
1598
1599                 err = tipc_nl_parse_link_prop(attrs[TIPC_NLA_LINK_PROP],
1600                                               props);
1601                 if (err) {
1602                         res = err;
1603                         goto out;
1604                 }
1605
1606                 if (props[TIPC_NLA_PROP_TOL]) {
1607                         u32 tol;
1608
1609                         tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
1610                         link->tolerance = tol;
1611                         tipc_link_proto_xmit(link, STATE_MSG, 0, 0, tol, 0);
1612                 }
1613                 if (props[TIPC_NLA_PROP_PRIO]) {
1614                         u32 prio;
1615
1616                         prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
1617                         link->priority = prio;
1618                         tipc_link_proto_xmit(link, STATE_MSG, 0, 0, 0, prio);
1619                 }
1620                 if (props[TIPC_NLA_PROP_WIN]) {
1621                         u32 win;
1622
1623                         win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
1624                         tipc_link_set_queue_limits(link, win);
1625                 }
1626         }
1627
1628 out:
1629         tipc_node_unlock(node);
1630
1631         return res;
1632 }
1633
1634 static int __tipc_nl_add_stats(struct sk_buff *skb, struct tipc_stats *s)
1635 {
1636         int i;
1637         struct nlattr *stats;
1638
1639         struct nla_map {
1640                 u32 key;
1641                 u32 val;
1642         };
1643
1644         struct nla_map map[] = {
1645                 {TIPC_NLA_STATS_RX_INFO, s->recv_info},
1646                 {TIPC_NLA_STATS_RX_FRAGMENTS, s->recv_fragments},
1647                 {TIPC_NLA_STATS_RX_FRAGMENTED, s->recv_fragmented},
1648                 {TIPC_NLA_STATS_RX_BUNDLES, s->recv_bundles},
1649                 {TIPC_NLA_STATS_RX_BUNDLED, s->recv_bundled},
1650                 {TIPC_NLA_STATS_TX_INFO, s->sent_info},
1651                 {TIPC_NLA_STATS_TX_FRAGMENTS, s->sent_fragments},
1652                 {TIPC_NLA_STATS_TX_FRAGMENTED, s->sent_fragmented},
1653                 {TIPC_NLA_STATS_TX_BUNDLES, s->sent_bundles},
1654                 {TIPC_NLA_STATS_TX_BUNDLED, s->sent_bundled},
1655                 {TIPC_NLA_STATS_MSG_PROF_TOT, (s->msg_length_counts) ?
1656                         s->msg_length_counts : 1},
1657                 {TIPC_NLA_STATS_MSG_LEN_CNT, s->msg_length_counts},
1658                 {TIPC_NLA_STATS_MSG_LEN_TOT, s->msg_lengths_total},
1659                 {TIPC_NLA_STATS_MSG_LEN_P0, s->msg_length_profile[0]},
1660                 {TIPC_NLA_STATS_MSG_LEN_P1, s->msg_length_profile[1]},
1661                 {TIPC_NLA_STATS_MSG_LEN_P2, s->msg_length_profile[2]},
1662                 {TIPC_NLA_STATS_MSG_LEN_P3, s->msg_length_profile[3]},
1663                 {TIPC_NLA_STATS_MSG_LEN_P4, s->msg_length_profile[4]},
1664                 {TIPC_NLA_STATS_MSG_LEN_P5, s->msg_length_profile[5]},
1665                 {TIPC_NLA_STATS_MSG_LEN_P6, s->msg_length_profile[6]},
1666                 {TIPC_NLA_STATS_RX_STATES, s->recv_states},
1667                 {TIPC_NLA_STATS_RX_PROBES, s->recv_probes},
1668                 {TIPC_NLA_STATS_RX_NACKS, s->recv_nacks},
1669                 {TIPC_NLA_STATS_RX_DEFERRED, s->deferred_recv},
1670                 {TIPC_NLA_STATS_TX_STATES, s->sent_states},
1671                 {TIPC_NLA_STATS_TX_PROBES, s->sent_probes},
1672                 {TIPC_NLA_STATS_TX_NACKS, s->sent_nacks},
1673                 {TIPC_NLA_STATS_TX_ACKS, s->sent_acks},
1674                 {TIPC_NLA_STATS_RETRANSMITTED, s->retransmitted},
1675                 {TIPC_NLA_STATS_DUPLICATES, s->duplicates},
1676                 {TIPC_NLA_STATS_LINK_CONGS, s->link_congs},
1677                 {TIPC_NLA_STATS_MAX_QUEUE, s->max_queue_sz},
1678                 {TIPC_NLA_STATS_AVG_QUEUE, s->queue_sz_counts ?
1679                         (s->accu_queue_sz / s->queue_sz_counts) : 0}
1680         };
1681
1682         stats = nla_nest_start(skb, TIPC_NLA_LINK_STATS);
1683         if (!stats)
1684                 return -EMSGSIZE;
1685
1686         for (i = 0; i <  ARRAY_SIZE(map); i++)
1687                 if (nla_put_u32(skb, map[i].key, map[i].val))
1688                         goto msg_full;
1689
1690         nla_nest_end(skb, stats);
1691
1692         return 0;
1693 msg_full:
1694         nla_nest_cancel(skb, stats);
1695
1696         return -EMSGSIZE;
1697 }
1698
1699 /* Caller should hold appropriate locks to protect the link */
1700 static int __tipc_nl_add_link(struct net *net, struct tipc_nl_msg *msg,
1701                               struct tipc_link *link, int nlflags)
1702 {
1703         int err;
1704         void *hdr;
1705         struct nlattr *attrs;
1706         struct nlattr *prop;
1707         struct tipc_net *tn = net_generic(net, tipc_net_id);
1708
1709         hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
1710                           nlflags, TIPC_NL_LINK_GET);
1711         if (!hdr)
1712                 return -EMSGSIZE;
1713
1714         attrs = nla_nest_start(msg->skb, TIPC_NLA_LINK);
1715         if (!attrs)
1716                 goto msg_full;
1717
1718         if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, link->name))
1719                 goto attr_msg_full;
1720         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_DEST,
1721                         tipc_cluster_mask(tn->own_addr)))
1722                 goto attr_msg_full;
1723         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_MTU, link->mtu))
1724                 goto attr_msg_full;
1725         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, link->rcv_nxt))
1726                 goto attr_msg_full;
1727         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, link->snd_nxt))
1728                 goto attr_msg_full;
1729
1730         if (tipc_link_is_up(link))
1731                 if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
1732                         goto attr_msg_full;
1733         if (tipc_link_is_active(link))
1734                 if (nla_put_flag(msg->skb, TIPC_NLA_LINK_ACTIVE))
1735                         goto attr_msg_full;
1736
1737         prop = nla_nest_start(msg->skb, TIPC_NLA_LINK_PROP);
1738         if (!prop)
1739                 goto attr_msg_full;
1740         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
1741                 goto prop_msg_full;
1742         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_TOL, link->tolerance))
1743                 goto prop_msg_full;
1744         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN,
1745                         link->window))
1746                 goto prop_msg_full;
1747         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
1748                 goto prop_msg_full;
1749         nla_nest_end(msg->skb, prop);
1750
1751         err = __tipc_nl_add_stats(msg->skb, &link->stats);
1752         if (err)
1753                 goto attr_msg_full;
1754
1755         nla_nest_end(msg->skb, attrs);
1756         genlmsg_end(msg->skb, hdr);
1757
1758         return 0;
1759
1760 prop_msg_full:
1761         nla_nest_cancel(msg->skb, prop);
1762 attr_msg_full:
1763         nla_nest_cancel(msg->skb, attrs);
1764 msg_full:
1765         genlmsg_cancel(msg->skb, hdr);
1766
1767         return -EMSGSIZE;
1768 }
1769
1770 /* Caller should hold node lock  */
1771 static int __tipc_nl_add_node_links(struct net *net, struct tipc_nl_msg *msg,
1772                                     struct tipc_node *node, u32 *prev_link)
1773 {
1774         u32 i;
1775         int err;
1776
1777         for (i = *prev_link; i < MAX_BEARERS; i++) {
1778                 *prev_link = i;
1779
1780                 if (!node->links[i].link)
1781                         continue;
1782
1783                 err = __tipc_nl_add_link(net, msg,
1784                                          node->links[i].link, NLM_F_MULTI);
1785                 if (err)
1786                         return err;
1787         }
1788         *prev_link = 0;
1789
1790         return 0;
1791 }
1792
1793 int tipc_nl_link_dump(struct sk_buff *skb, struct netlink_callback *cb)
1794 {
1795         struct net *net = sock_net(skb->sk);
1796         struct tipc_net *tn = net_generic(net, tipc_net_id);
1797         struct tipc_node *node;
1798         struct tipc_nl_msg msg;
1799         u32 prev_node = cb->args[0];
1800         u32 prev_link = cb->args[1];
1801         int done = cb->args[2];
1802         int err;
1803
1804         if (done)
1805                 return 0;
1806
1807         msg.skb = skb;
1808         msg.portid = NETLINK_CB(cb->skb).portid;
1809         msg.seq = cb->nlh->nlmsg_seq;
1810
1811         rcu_read_lock();
1812         if (prev_node) {
1813                 node = tipc_node_find(net, prev_node);
1814                 if (!node) {
1815                         /* We never set seq or call nl_dump_check_consistent()
1816                          * this means that setting prev_seq here will cause the
1817                          * consistence check to fail in the netlink callback
1818                          * handler. Resulting in the last NLMSG_DONE message
1819                          * having the NLM_F_DUMP_INTR flag set.
1820                          */
1821                         cb->prev_seq = 1;
1822                         goto out;
1823                 }
1824                 tipc_node_put(node);
1825
1826                 list_for_each_entry_continue_rcu(node, &tn->node_list,
1827                                                  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         } else {
1838                 err = tipc_nl_add_bc_link(net, &msg);
1839                 if (err)
1840                         goto out;
1841
1842                 list_for_each_entry_rcu(node, &tn->node_list, 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         }
1853         done = 1;
1854 out:
1855         rcu_read_unlock();
1856
1857         cb->args[0] = prev_node;
1858         cb->args[1] = prev_link;
1859         cb->args[2] = done;
1860
1861         return skb->len;
1862 }
1863
1864 int tipc_nl_link_get(struct sk_buff *skb, struct genl_info *info)
1865 {
1866         struct net *net = genl_info_net(info);
1867         struct tipc_nl_msg msg;
1868         char *name;
1869         int err;
1870
1871         msg.portid = info->snd_portid;
1872         msg.seq = info->snd_seq;
1873
1874         if (!info->attrs[TIPC_NLA_LINK_NAME])
1875                 return -EINVAL;
1876         name = nla_data(info->attrs[TIPC_NLA_LINK_NAME]);
1877
1878         msg.skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
1879         if (!msg.skb)
1880                 return -ENOMEM;
1881
1882         if (strcmp(name, tipc_bclink_name) == 0) {
1883                 err = tipc_nl_add_bc_link(net, &msg);
1884                 if (err) {
1885                         nlmsg_free(msg.skb);
1886                         return err;
1887                 }
1888         } else {
1889                 int bearer_id;
1890                 struct tipc_node *node;
1891                 struct tipc_link *link;
1892
1893                 node = tipc_link_find_owner(net, name, &bearer_id);
1894                 if (!node)
1895                         return -EINVAL;
1896
1897                 tipc_node_lock(node);
1898                 link = node->links[bearer_id].link;
1899                 if (!link) {
1900                         tipc_node_unlock(node);
1901                         nlmsg_free(msg.skb);
1902                         return -EINVAL;
1903                 }
1904
1905                 err = __tipc_nl_add_link(net, &msg, link, 0);
1906                 tipc_node_unlock(node);
1907                 if (err) {
1908                         nlmsg_free(msg.skb);
1909                         return err;
1910                 }
1911         }
1912
1913         return genlmsg_reply(msg.skb, info);
1914 }
1915
1916 int tipc_nl_link_reset_stats(struct sk_buff *skb, struct genl_info *info)
1917 {
1918         int err;
1919         char *link_name;
1920         unsigned int bearer_id;
1921         struct tipc_link *link;
1922         struct tipc_node *node;
1923         struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
1924         struct net *net = sock_net(skb->sk);
1925
1926         if (!info->attrs[TIPC_NLA_LINK])
1927                 return -EINVAL;
1928
1929         err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
1930                                info->attrs[TIPC_NLA_LINK],
1931                                tipc_nl_link_policy);
1932         if (err)
1933                 return err;
1934
1935         if (!attrs[TIPC_NLA_LINK_NAME])
1936                 return -EINVAL;
1937
1938         link_name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
1939
1940         if (strcmp(link_name, tipc_bclink_name) == 0) {
1941                 err = tipc_bclink_reset_stats(net);
1942                 if (err)
1943                         return err;
1944                 return 0;
1945         }
1946
1947         node = tipc_link_find_owner(net, link_name, &bearer_id);
1948         if (!node)
1949                 return -EINVAL;
1950
1951         tipc_node_lock(node);
1952
1953         link = node->links[bearer_id].link;
1954         if (!link) {
1955                 tipc_node_unlock(node);
1956                 return -EINVAL;
1957         }
1958
1959         link_reset_statistics(link);
1960
1961         tipc_node_unlock(node);
1962
1963         return 0;
1964 }