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 changeover error, ";
  52 static const char *link_rst_msg = "Resetting link ";
  53 static const char *link_unk_evt = "Unknown link event ";
  54
  55 static const struct nla_policy tipc_nl_link_policy[TIPC_NLA_LINK_MAX + 1] = {
  56         [TIPC_NLA_LINK_UNSPEC]          = { .type = NLA_UNSPEC },
  57         [TIPC_NLA_LINK_NAME] = {
  58                 .type = NLA_STRING,
  59                 .len = TIPC_MAX_LINK_NAME
  60         },
  61         [TIPC_NLA_LINK_MTU]             = { .type = NLA_U32 },
  62         [TIPC_NLA_LINK_BROADCAST]       = { .type = NLA_FLAG },
  63         [TIPC_NLA_LINK_UP]              = { .type = NLA_FLAG },
  64         [TIPC_NLA_LINK_ACTIVE]          = { .type = NLA_FLAG },
  65         [TIPC_NLA_LINK_PROP]            = { .type = NLA_NESTED },
  66         [TIPC_NLA_LINK_STATS]           = { .type = NLA_NESTED },
  67         [TIPC_NLA_LINK_RX]              = { .type = NLA_U32 },
  68         [TIPC_NLA_LINK_TX]              = { .type = NLA_U32 }
  69 };
  70
  71 /* Properties valid for media, bearar and link */
  72 static const struct nla_policy tipc_nl_prop_policy[TIPC_NLA_PROP_MAX + 1] = {
  73         [TIPC_NLA_PROP_UNSPEC]          = { .type = NLA_UNSPEC },
  74         [TIPC_NLA_PROP_PRIO]            = { .type = NLA_U32 },
  75         [TIPC_NLA_PROP_TOL]             = { .type = NLA_U32 },
  76         [TIPC_NLA_PROP_WIN]             = { .type = NLA_U32 }
  77 };
  78
  79 /*
  80  * Out-of-range value for link session numbers
  81  */
  82 #define WILDCARD_SESSION 0x10000
  83
  84 /* State value stored in 'failover_pkts'
  85  */
  86 #define FIRST_FAILOVER 0xffffu
  87
  88 /* Link FSM states and events:
  89  */
  90 enum {
  91         TIPC_LINK_WORKING,
  92         TIPC_LINK_PROBING,
  93         TIPC_LINK_RESETTING,
  94         TIPC_LINK_ESTABLISHING
  95 };
  96
  97 enum {
  98         PEER_RESET_EVT    = RESET_MSG,
  99         ACTIVATE_EVT      = ACTIVATE_MSG,
 100         TRAFFIC_EVT,      /* Any other valid msg from peer */
 101         SILENCE_EVT       /* Peer was silent during last timer interval*/
 102 };
 103
 104 /* Link FSM state checking routines
 105  */
 106 static int link_working(struct tipc_link *l)
 107 {
 108         return l->state == TIPC_LINK_WORKING;
 109 }
 110
 111 static int link_probing(struct tipc_link *l)
 112 {
 113         return l->state == TIPC_LINK_PROBING;
 114 }
 115
 116 static int link_resetting(struct tipc_link *l)
 117 {
 118         return l->state == TIPC_LINK_RESETTING;
 119 }
 120
 121 static int link_establishing(struct tipc_link *l)
 122 {
 123         return l->state == TIPC_LINK_ESTABLISHING;
 124 }
 125
 126 static void link_handle_out_of_seq_msg(struct tipc_link *link,
 127                                        struct sk_buff *skb);
 128 static void tipc_link_proto_rcv(struct tipc_link *link,
 129                                 struct sk_buff *skb);
 130 static void link_set_supervision_props(struct tipc_link *l_ptr, u32 tol);
 131 static void link_state_event(struct tipc_link *l_ptr, u32 event);
 132 static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
 133                                       u16 rcvgap, int tolerance, int priority,
 134                                       struct sk_buff_head *xmitq);
 135 static void link_reset_statistics(struct tipc_link *l_ptr);
 136 static void link_print(struct tipc_link *l_ptr, const char *str);
 137 static void tipc_link_sync_xmit(struct tipc_link *l);
 138 static void tipc_link_sync_rcv(struct tipc_node *n, struct sk_buff *buf);
 139 static void tipc_link_input(struct tipc_link *l, struct sk_buff *skb);
 140 static bool tipc_data_input(struct tipc_link *l, struct sk_buff *skb);
 141 static bool tipc_link_failover_rcv(struct tipc_link *l, struct sk_buff **skb);
 142 static void link_set_timer(struct tipc_link *link, unsigned long time);
 143 static void link_activate(struct tipc_link *link);
 144
 145 /*
 146  *  Simple link routines
 147  */
 148 static unsigned int align(unsigned int i)
 149 {
 150         return (i + 3) & ~3u;
 151 }
 152
 153 static void tipc_link_release(struct kref *kref)
 154 {
 155         kfree(container_of(kref, struct tipc_link, ref));
 156 }
 157
 158 static void tipc_link_get(struct tipc_link *l_ptr)
 159 {
 160         kref_get(&l_ptr->ref);
 161 }
 162
 163 static void tipc_link_put(struct tipc_link *l_ptr)
 164 {
 165         kref_put(&l_ptr->ref, tipc_link_release);
 166 }
 167
 168 static struct tipc_link *tipc_parallel_link(struct tipc_link *l)
 169 {
 170         struct tipc_node *n = l->owner;
 171
 172         if (node_active_link(n, 0) != l)
 173                 return node_active_link(n, 0);
 174         return node_active_link(n, 1);
 175 }
 176
 177 /*
 178  *  Simple non-static link routines (i.e. referenced outside this file)
 179  */
 180 int tipc_link_is_up(struct tipc_link *l_ptr)
 181 {
 182         if (!l_ptr)
 183                 return 0;
 184         return link_working(l_ptr) || link_probing(l_ptr);
 185 }
 186
 187 int tipc_link_is_active(struct tipc_link *l)
 188 {
 189         struct tipc_node *n = l->owner;
 190
 191         return (node_active_link(n, 0) == l) || (node_active_link(n, 1) == l);
 192 }
 193
 194 /**
 195  * link_timeout - handle expiration of link timer
 196  */
 197 static void link_timeout(unsigned long data)
 198 {
 199         struct tipc_link *l = (struct tipc_link *)data;
 200         struct sk_buff_head xmitq;
 201         struct sk_buff *skb;
 202         int rc;
 203
 204         __skb_queue_head_init(&xmitq);
 205
 206         tipc_node_lock(l->owner);
 207
 208         rc = tipc_link_timeout(l, &xmitq);
 209
 210         if (rc & TIPC_LINK_DOWN_EVT)
 211                 tipc_link_reset(l);
 212
 213         skb = __skb_dequeue(&xmitq);
 214         if (skb)
 215                 tipc_bearer_send(l->owner->net, l->bearer_id,
 216                                  skb, &l->media_addr);
 217         link_set_timer(l, l->keepalive_intv);
 218         tipc_node_unlock(l->owner);
 219         tipc_link_put(l);
 220 }
 221
 222 static void link_set_timer(struct tipc_link *link, unsigned long time)
 223 {
 224         if (!mod_timer(&link->timer, jiffies + time))
 225                 tipc_link_get(link);
 226 }
 227
 228 /**
 229  * tipc_link_create - create a new link
 230  * @n_ptr: pointer to associated node
 231  * @b_ptr: pointer to associated bearer
 232  * @media_addr: media address to use when sending messages over link
 233  *
 234  * Returns pointer to link.
 235  */
 236 struct tipc_link *tipc_link_create(struct tipc_node *n_ptr,
 237                                    struct tipc_bearer *b_ptr,
 238                                    const struct tipc_media_addr *media_addr,
 239                                    struct sk_buff_head *inputq,
 240                                    struct sk_buff_head *namedq)
 241 {
 242         struct tipc_net *tn = net_generic(n_ptr->net, tipc_net_id);
 243         struct tipc_link *l_ptr;
 244         struct tipc_msg *msg;
 245         char *if_name;
 246         char addr_string[16];
 247         u32 peer = n_ptr->addr;
 248
 249         if (n_ptr->link_cnt >= MAX_BEARERS) {
 250                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 251                 pr_err("Cannot establish %uth link to %s. Max %u allowed.\n",
 252                        n_ptr->link_cnt, addr_string, MAX_BEARERS);
 253                 return NULL;
 254         }
 255
 256         if (n_ptr->links[b_ptr->identity].link) {
 257                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 258                 pr_err("Attempt to establish second link on <%s> to %s\n",
 259                        b_ptr->name, addr_string);
 260                 return NULL;
 261         }
 262
 263         l_ptr = kzalloc(sizeof(*l_ptr), GFP_ATOMIC);
 264         if (!l_ptr) {
 265                 pr_warn("Link creation failed, no memory\n");
 266                 return NULL;
 267         }
 268         kref_init(&l_ptr->ref);
 269         l_ptr->addr = peer;
 270         if_name = strchr(b_ptr->name, ':') + 1;
 271         sprintf(l_ptr->name, "%u.%u.%u:%s-%u.%u.%u:unknown",
 272                 tipc_zone(tn->own_addr), tipc_cluster(tn->own_addr),
 273                 tipc_node(tn->own_addr),
 274                 if_name,
 275                 tipc_zone(peer), tipc_cluster(peer), tipc_node(peer));
 276                 /* note: peer i/f name is updated by reset/activate message */
 277         memcpy(&l_ptr->media_addr, media_addr, sizeof(*media_addr));
 278         l_ptr->owner = n_ptr;
 279         l_ptr->peer_session = WILDCARD_SESSION;
 280         l_ptr->bearer_id = b_ptr->identity;
 281         link_set_supervision_props(l_ptr, b_ptr->tolerance);
 282         l_ptr->state = TIPC_LINK_RESETTING;
 283
 284         l_ptr->pmsg = (struct tipc_msg *)&l_ptr->proto_msg;
 285         msg = l_ptr->pmsg;
 286         tipc_msg_init(tn->own_addr, msg, LINK_PROTOCOL, RESET_MSG, INT_H_SIZE,
 287                       l_ptr->addr);
 288         msg_set_size(msg, sizeof(l_ptr->proto_msg));
 289         msg_set_session(msg, (tn->random & 0xffff));
 290         msg_set_bearer_id(msg, b_ptr->identity);
 291         strcpy((char *)msg_data(msg), if_name);
 292         l_ptr->net_plane = b_ptr->net_plane;
 293         l_ptr->advertised_mtu = b_ptr->mtu;
 294         l_ptr->mtu = l_ptr->advertised_mtu;
 295         l_ptr->priority = b_ptr->priority;
 296         tipc_link_set_queue_limits(l_ptr, b_ptr->window);
 297         l_ptr->snd_nxt = 1;
 298         __skb_queue_head_init(&l_ptr->transmq);
 299         __skb_queue_head_init(&l_ptr->backlogq);
 300         __skb_queue_head_init(&l_ptr->deferdq);
 301         skb_queue_head_init(&l_ptr->wakeupq);
 302         l_ptr->inputq = inputq;
 303         l_ptr->namedq = namedq;
 304         skb_queue_head_init(l_ptr->inputq);
 305         link_reset_statistics(l_ptr);
 306         tipc_node_attach_link(n_ptr, l_ptr);
 307         setup_timer(&l_ptr->timer, link_timeout, (unsigned long)l_ptr);
 308         link_set_timer(l_ptr, l_ptr->keepalive_intv);
 309         return l_ptr;
 310 }
 311
 312 /**
 313  * tipc_link_delete - Delete a link
 314  * @l: link to be deleted
 315  */
 316 void tipc_link_delete(struct tipc_link *l)
 317 {
 318         tipc_link_reset(l);
 319         if (del_timer(&l->timer))
 320                 tipc_link_put(l);
 321         /* Delete link now, or when timer is finished: */
 322         tipc_link_reset_fragments(l);
 323         tipc_node_detach_link(l->owner, l);
 324         tipc_link_put(l);
 325 }
 326
 327 void tipc_link_delete_list(struct net *net, unsigned int bearer_id)
 328 {
 329         struct tipc_net *tn = net_generic(net, tipc_net_id);
 330         struct tipc_link *link;
 331         struct tipc_node *node;
 332
 333         rcu_read_lock();
 334         list_for_each_entry_rcu(node, &tn->node_list, list) {
 335                 tipc_node_lock(node);
 336                 link = node->links[bearer_id].link;
 337                 if (link)
 338                         tipc_link_delete(link);
 339                 tipc_node_unlock(node);
 340         }
 341         rcu_read_unlock();
 342 }
 343
 344 /**
 345  * tipc_link_fsm_evt - link finite state machine
 346  * @l: pointer to link
 347  * @evt: state machine event to be processed
 348  * @xmitq: queue to prepend created protocol message, if any
 349  */
 350 static int tipc_link_fsm_evt(struct tipc_link *l, int evt,
 351                              struct sk_buff_head *xmitq)
 352 {
 353         int mtyp = 0, rc = 0;
 354         struct tipc_link *pl;
 355         enum {
 356                 LINK_RESET    = 1,
 357                 LINK_ACTIVATE = (1 << 1),
 358                 SND_PROBE     = (1 << 2),
 359                 SND_STATE     = (1 << 3),
 360                 SND_RESET     = (1 << 4),
 361                 SND_ACTIVATE  = (1 << 5)
 362         } actions = 0;
 363
 364         if (l->exec_mode == TIPC_LINK_BLOCKED)
 365                 return rc;
 366
 367         switch (l->state) {
 368         case TIPC_LINK_WORKING:
 369                 switch (evt) {
 370                 case TRAFFIC_EVT:
 371                 case ACTIVATE_EVT:
 372                         break;
 373                 case SILENCE_EVT:
 374                         l->state = TIPC_LINK_PROBING;
 375                         actions |= SND_PROBE;
 376                         break;
 377                 case PEER_RESET_EVT:
 378                         actions |= LINK_RESET | SND_ACTIVATE;
 379                         break;
 380                 default:
 381                         pr_debug("%s%u WORKING\n", link_unk_evt, evt);
 382                 }
 383                 break;
 384         case TIPC_LINK_PROBING:
 385                 switch (evt) {
 386                 case TRAFFIC_EVT:
 387                 case ACTIVATE_EVT:
 388                         l->state = TIPC_LINK_WORKING;
 389                         break;
 390                 case PEER_RESET_EVT:
 391                         actions |= LINK_RESET | SND_ACTIVATE;
 392                         break;
 393                 case SILENCE_EVT:
 394                         if (l->silent_intv_cnt <= l->abort_limit) {
 395                                 actions |= SND_PROBE;
 396                                 break;
 397                         }
 398                         actions |= LINK_RESET | SND_RESET;
 399                         break;
 400                 default:
 401                         pr_err("%s%u PROBING\n", link_unk_evt, evt);
 402                 }
 403                 break;
 404         case TIPC_LINK_RESETTING:
 405                 switch (evt) {
 406                 case TRAFFIC_EVT:
 407                         break;
 408                 case ACTIVATE_EVT:
 409                         pl = node_active_link(l->owner, 0);
 410                         if (pl && link_probing(pl))
 411                                 break;
 412                         actions |= LINK_ACTIVATE;
 413                         if (l->owner->working_links == 1)
 414                                 tipc_link_sync_xmit(l);
 415                         break;
 416                 case PEER_RESET_EVT:
 417                         l->state = TIPC_LINK_ESTABLISHING;
 418                         actions |= SND_ACTIVATE;
 419                         break;
 420                 case SILENCE_EVT:
 421                         actions |= SND_RESET;
 422                         break;
 423                 default:
 424                         pr_err("%s%u in RESETTING\n", link_unk_evt, evt);
 425                 }
 426                 break;
 427         case TIPC_LINK_ESTABLISHING:
 428                 switch (evt) {
 429                 case TRAFFIC_EVT:
 430                 case ACTIVATE_EVT:
 431                         pl = node_active_link(l->owner, 0);
 432                         if (pl && link_probing(pl))
 433                                 break;
 434                         actions |= LINK_ACTIVATE;
 435                         if (l->owner->working_links == 1)
 436                                 tipc_link_sync_xmit(l);
 437                         break;
 438                 case PEER_RESET_EVT:
 439                         break;
 440                 case SILENCE_EVT:
 441                         actions |= SND_ACTIVATE;
 442                         break;
 443                 default:
 444                         pr_err("%s%u ESTABLISHING\n", link_unk_evt, evt);
 445                 }
 446                 break;
 447         default:
 448                 pr_err("Unknown link state %u/%u\n", l->state, evt);
 449         }
 450
 451         /* Perform actions as decided by FSM */
 452         if (actions & LINK_RESET) {
 453                 l->exec_mode = TIPC_LINK_BLOCKED;
 454                 rc |= TIPC_LINK_DOWN_EVT;
 455         }
 456         if (actions & LINK_ACTIVATE) {
 457                 l->exec_mode = TIPC_LINK_OPEN;
 458                 rc |= TIPC_LINK_UP_EVT;
 459         }
 460         if (actions & (SND_STATE | SND_PROBE))
 461                 mtyp = STATE_MSG;
 462         if (actions & SND_RESET)
 463                 mtyp = RESET_MSG;
 464         if (actions & SND_ACTIVATE)
 465                 mtyp = ACTIVATE_MSG;
 466         if (actions & (SND_PROBE | SND_STATE | SND_RESET | SND_ACTIVATE))
 467                 tipc_link_build_proto_msg(l, mtyp, actions & SND_PROBE,
 468                                           0, 0, 0, xmitq);
 469         return rc;
 470 }
 471
 472 /* link_profile_stats - update statistical profiling of traffic
 473  */
 474 static void link_profile_stats(struct tipc_link *l)
 475 {
 476         struct sk_buff *skb;
 477         struct tipc_msg *msg;
 478         int length;
 479
 480         /* Update counters used in statistical profiling of send traffic */
 481         l->stats.accu_queue_sz += skb_queue_len(&l->transmq);
 482         l->stats.queue_sz_counts++;
 483
 484         skb = skb_peek(&l->transmq);
 485         if (!skb)
 486                 return;
 487         msg = buf_msg(skb);
 488         length = msg_size(msg);
 489
 490         if (msg_user(msg) == MSG_FRAGMENTER) {
 491                 if (msg_type(msg) != FIRST_FRAGMENT)
 492                         return;
 493                 length = msg_size(msg_get_wrapped(msg));
 494         }
 495         l->stats.msg_lengths_total += length;
 496         l->stats.msg_length_counts++;
 497         if (length <= 64)
 498                 l->stats.msg_length_profile[0]++;
 499         else if (length <= 256)
 500                 l->stats.msg_length_profile[1]++;
 501         else if (length <= 1024)
 502                 l->stats.msg_length_profile[2]++;
 503         else if (length <= 4096)
 504                 l->stats.msg_length_profile[3]++;
 505         else if (length <= 16384)
 506                 l->stats.msg_length_profile[4]++;
 507         else if (length <= 32768)
 508                 l->stats.msg_length_profile[5]++;
 509         else
 510                 l->stats.msg_length_profile[6]++;
 511 }
 512
 513 /* tipc_link_timeout - perform periodic task as instructed from node timeout
 514  */
 515 int tipc_link_timeout(struct tipc_link *l, struct sk_buff_head *xmitq)
 516 {
 517         int rc = 0;
 518
 519         link_profile_stats(l);
 520         if (l->silent_intv_cnt)
 521                 rc = tipc_link_fsm_evt(l, SILENCE_EVT, xmitq);
 522         else if (link_working(l) && tipc_bclink_acks_missing(l->owner))
 523                 tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, 0, xmitq);
 524         l->silent_intv_cnt++;
 525         return rc;
 526 }
 527
 528 /**
 529  * link_schedule_user - schedule a message sender for wakeup after congestion
 530  * @link: congested link
 531  * @list: message that was attempted sent
 532  * Create pseudo msg to send back to user when congestion abates
 533  * Does not consume buffer list
 534  */
 535 static int link_schedule_user(struct tipc_link *link, struct sk_buff_head *list)
 536 {
 537         struct tipc_msg *msg = buf_msg(skb_peek(list));
 538         int imp = msg_importance(msg);
 539         u32 oport = msg_origport(msg);
 540         u32 addr = link_own_addr(link);
 541         struct sk_buff *skb;
 542
 543         /* This really cannot happen...  */
 544         if (unlikely(imp > TIPC_CRITICAL_IMPORTANCE)) {
 545                 pr_warn("%s<%s>, send queue full", link_rst_msg, link->name);
 546                 return -ENOBUFS;
 547         }
 548         /* Non-blocking sender: */
 549         if (TIPC_SKB_CB(skb_peek(list))->wakeup_pending)
 550                 return -ELINKCONG;
 551
 552         /* Create and schedule wakeup pseudo message */
 553         skb = tipc_msg_create(SOCK_WAKEUP, 0, INT_H_SIZE, 0,
 554                               addr, addr, oport, 0, 0);
 555         if (!skb)
 556                 return -ENOBUFS;
 557         TIPC_SKB_CB(skb)->chain_sz = skb_queue_len(list);
 558         TIPC_SKB_CB(skb)->chain_imp = imp;
 559         skb_queue_tail(&link->wakeupq, skb);
 560         link->stats.link_congs++;
 561         return -ELINKCONG;
 562 }
 563
 564 /**
 565  * link_prepare_wakeup - prepare users for wakeup after congestion
 566  * @link: congested link
 567  * Move a number of waiting users, as permitted by available space in
 568  * the send queue, from link wait queue to node wait queue for wakeup
 569  */
 570 void link_prepare_wakeup(struct tipc_link *l)
 571 {
 572         int pnd[TIPC_SYSTEM_IMPORTANCE + 1] = {0,};
 573         int imp, lim;
 574         struct sk_buff *skb, *tmp;
 575
 576         skb_queue_walk_safe(&l->wakeupq, skb, tmp) {
 577                 imp = TIPC_SKB_CB(skb)->chain_imp;
 578                 lim = l->window + l->backlog[imp].limit;
 579                 pnd[imp] += TIPC_SKB_CB(skb)->chain_sz;
 580                 if ((pnd[imp] + l->backlog[imp].len) >= lim)
 581                         break;
 582                 skb_unlink(skb, &l->wakeupq);
 583                 skb_queue_tail(l->inputq, skb);
 584                 l->owner->inputq = l->inputq;
 585                 l->owner->action_flags |= TIPC_MSG_EVT;
 586         }
 587 }
 588
 589 /**
 590  * tipc_link_reset_fragments - purge link's inbound message fragments queue
 591  * @l_ptr: pointer to link
 592  */
 593 void tipc_link_reset_fragments(struct tipc_link *l_ptr)
 594 {
 595         kfree_skb(l_ptr->reasm_buf);
 596         l_ptr->reasm_buf = NULL;
 597 }
 598
 599 void tipc_link_purge_backlog(struct tipc_link *l)
 600 {
 601         __skb_queue_purge(&l->backlogq);
 602         l->backlog[TIPC_LOW_IMPORTANCE].len = 0;
 603         l->backlog[TIPC_MEDIUM_IMPORTANCE].len = 0;
 604         l->backlog[TIPC_HIGH_IMPORTANCE].len = 0;
 605         l->backlog[TIPC_CRITICAL_IMPORTANCE].len = 0;
 606         l->backlog[TIPC_SYSTEM_IMPORTANCE].len = 0;
 607 }
 608
 609 /**
 610  * tipc_link_purge_queues - purge all pkt queues associated with link
 611  * @l_ptr: pointer to link
 612  */
 613 void tipc_link_purge_queues(struct tipc_link *l_ptr)
 614 {
 615         __skb_queue_purge(&l_ptr->deferdq);
 616         __skb_queue_purge(&l_ptr->transmq);
 617         tipc_link_purge_backlog(l_ptr);
 618         tipc_link_reset_fragments(l_ptr);
 619 }
 620
 621 void tipc_link_reset(struct tipc_link *l_ptr)
 622 {
 623         u32 prev_state = l_ptr->state;
 624         int was_active_link = tipc_link_is_active(l_ptr);
 625         struct tipc_node *owner = l_ptr->owner;
 626         struct tipc_link *pl = tipc_parallel_link(l_ptr);
 627
 628         msg_set_session(l_ptr->pmsg, ((msg_session(l_ptr->pmsg) + 1) & 0xffff));
 629
 630         /* Link is down, accept any session */
 631         l_ptr->peer_session = WILDCARD_SESSION;
 632
 633         /* Prepare for renewed mtu size negotiation */
 634         l_ptr->mtu = l_ptr->advertised_mtu;
 635
 636         l_ptr->state = TIPC_LINK_RESETTING;
 637
 638         if ((prev_state == TIPC_LINK_RESETTING) ||
 639             (prev_state == TIPC_LINK_ESTABLISHING))
 640                 return;
 641
 642         tipc_node_link_down(l_ptr->owner, l_ptr->bearer_id);
 643         tipc_bearer_remove_dest(owner->net, l_ptr->bearer_id, l_ptr->addr);
 644
 645         if (was_active_link && tipc_node_is_up(l_ptr->owner) && (pl != l_ptr)) {
 646                 l_ptr->exec_mode = TIPC_LINK_BLOCKED;
 647                 l_ptr->failover_checkpt = l_ptr->rcv_nxt;
 648                 pl->failover_pkts = FIRST_FAILOVER;
 649                 pl->failover_checkpt = l_ptr->rcv_nxt;
 650                 pl->failover_skb = l_ptr->reasm_buf;
 651         } else {
 652                 kfree_skb(l_ptr->reasm_buf);
 653         }
 654         /* Clean up all queues, except inputq: */
 655         __skb_queue_purge(&l_ptr->transmq);
 656         __skb_queue_purge(&l_ptr->deferdq);
 657         if (!owner->inputq)
 658                 owner->inputq = l_ptr->inputq;
 659         skb_queue_splice_init(&l_ptr->wakeupq, owner->inputq);
 660         if (!skb_queue_empty(owner->inputq))
 661                 owner->action_flags |= TIPC_MSG_EVT;
 662         tipc_link_purge_backlog(l_ptr);
 663         l_ptr->reasm_buf = NULL;
 664         l_ptr->rcv_unacked = 0;
 665         l_ptr->snd_nxt = 1;
 666         l_ptr->silent_intv_cnt = 0;
 667         l_ptr->stale_count = 0;
 668         link_reset_statistics(l_ptr);
 669 }
 670
 671 static void link_activate(struct tipc_link *link)
 672 {
 673         struct tipc_node *node = link->owner;
 674
 675         link->rcv_nxt = 1;
 676         link->stats.recv_info = 1;
 677         link->silent_intv_cnt = 0;
 678         link->state = TIPC_LINK_WORKING;
 679         link->exec_mode = TIPC_LINK_OPEN;
 680         tipc_node_link_up(node, link->bearer_id);
 681         tipc_bearer_add_dest(node->net, link->bearer_id, link->addr);
 682 }
 683
 684 /**
 685  * link_state_event - link finite state machine
 686  * @l_ptr: pointer to link
 687  * @event: state machine event to process
 688  */
 689 static void link_state_event(struct tipc_link *l, unsigned int evt)
 690 {
 691         int rc;
 692         struct sk_buff_head xmitq;
 693         struct sk_buff *skb;
 694
 695         if (l->exec_mode == TIPC_LINK_BLOCKED)
 696                 return;
 697
 698         __skb_queue_head_init(&xmitq);
 699
 700         rc = tipc_link_fsm_evt(l, evt, &xmitq);
 701
 702         if (rc & TIPC_LINK_UP_EVT)
 703                 link_activate(l);
 704
 705         if (rc & TIPC_LINK_DOWN_EVT)
 706                 tipc_link_reset(l);
 707
 708         skb = __skb_dequeue(&xmitq);
 709         if (!skb)
 710                 return;
 711         tipc_bearer_send(l->owner->net, l->bearer_id, skb, &l->media_addr);
 712 }
 713
 714 /**
 715  * __tipc_link_xmit(): same as tipc_link_xmit, but destlink is known & locked
 716  * @link: link to use
 717  * @list: chain of buffers containing message
 718  *
 719  * Consumes the buffer chain, except when returning an error code,
 720  * Returns 0 if success, or errno: -ELINKCONG, -EMSGSIZE or -ENOBUFS
 721  * Messages at TIPC_SYSTEM_IMPORTANCE are always accepted
 722  */
 723 int __tipc_link_xmit(struct net *net, struct tipc_link *link,
 724                      struct sk_buff_head *list)
 725 {
 726         struct tipc_msg *msg = buf_msg(skb_peek(list));
 727         unsigned int maxwin = link->window;
 728         unsigned int i, imp = msg_importance(msg);
 729         uint mtu = link->mtu;
 730         u16 ack = mod(link->rcv_nxt - 1);
 731         u16 seqno = link->snd_nxt;
 732         u16 bc_last_in = link->owner->bclink.last_in;
 733         struct tipc_media_addr *addr = &link->media_addr;
 734         struct sk_buff_head *transmq = &link->transmq;
 735         struct sk_buff_head *backlogq = &link->backlogq;
 736         struct sk_buff *skb, *bskb;
 737
 738         /* Match msg importance against this and all higher backlog limits: */
 739         for (i = imp; i <= TIPC_SYSTEM_IMPORTANCE; i++) {
 740                 if (unlikely(link->backlog[i].len >= link->backlog[i].limit))
 741                         return link_schedule_user(link, list);
 742         }
 743         if (unlikely(msg_size(msg) > mtu))
 744                 return -EMSGSIZE;
 745
 746         /* Prepare each packet for sending, and add to relevant queue: */
 747         while (skb_queue_len(list)) {
 748                 skb = skb_peek(list);
 749                 msg = buf_msg(skb);
 750                 msg_set_seqno(msg, seqno);
 751                 msg_set_ack(msg, ack);
 752                 msg_set_bcast_ack(msg, bc_last_in);
 753
 754                 if (likely(skb_queue_len(transmq) < maxwin)) {
 755                         __skb_dequeue(list);
 756                         __skb_queue_tail(transmq, skb);
 757                         tipc_bearer_send(net, link->bearer_id, skb, addr);
 758                         link->rcv_unacked = 0;
 759                         seqno++;
 760                         continue;
 761                 }
 762                 if (tipc_msg_bundle(skb_peek_tail(backlogq), msg, mtu)) {
 763                         kfree_skb(__skb_dequeue(list));
 764                         link->stats.sent_bundled++;
 765                         continue;
 766                 }
 767                 if (tipc_msg_make_bundle(&bskb, msg, mtu, link->addr)) {
 768                         kfree_skb(__skb_dequeue(list));
 769                         __skb_queue_tail(backlogq, bskb);
 770                         link->backlog[msg_importance(buf_msg(bskb))].len++;
 771                         link->stats.sent_bundled++;
 772                         link->stats.sent_bundles++;
 773                         continue;
 774                 }
 775                 link->backlog[imp].len += skb_queue_len(list);
 776                 skb_queue_splice_tail_init(list, backlogq);
 777         }
 778         link->snd_nxt = seqno;
 779         return 0;
 780 }
 781
 782 /**
 783  * tipc_link_xmit(): enqueue buffer list according to queue situation
 784  * @link: link to use
 785  * @list: chain of buffers containing message
 786  * @xmitq: returned list of packets to be sent by caller
 787  *
 788  * Consumes the buffer chain, except when returning -ELINKCONG,
 789  * since the caller then may want to make more send attempts.
 790  * Returns 0 if success, or errno: -ELINKCONG, -EMSGSIZE or -ENOBUFS
 791  * Messages at TIPC_SYSTEM_IMPORTANCE are always accepted
 792  */
 793 int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *list,
 794                    struct sk_buff_head *xmitq)
 795 {
 796         struct tipc_msg *hdr = buf_msg(skb_peek(list));
 797         unsigned int maxwin = l->window;
 798         unsigned int i, imp = msg_importance(hdr);
 799         unsigned int mtu = l->mtu;
 800         u16 ack = l->rcv_nxt - 1;
 801         u16 seqno = l->snd_nxt;
 802         u16 bc_last_in = l->owner->bclink.last_in;
 803         struct sk_buff_head *transmq = &l->transmq;
 804         struct sk_buff_head *backlogq = &l->backlogq;
 805         struct sk_buff *skb, *_skb, *bskb;
 806
 807         /* Match msg importance against this and all higher backlog limits: */
 808         for (i = imp; i <= TIPC_SYSTEM_IMPORTANCE; i++) {
 809                 if (unlikely(l->backlog[i].len >= l->backlog[i].limit))
 810                         return link_schedule_user(l, list);
 811         }
 812         if (unlikely(msg_size(hdr) > mtu))
 813                 return -EMSGSIZE;
 814
 815         /* Prepare each packet for sending, and add to relevant queue: */
 816         while (skb_queue_len(list)) {
 817                 skb = skb_peek(list);
 818                 hdr = buf_msg(skb);
 819                 msg_set_seqno(hdr, seqno);
 820                 msg_set_ack(hdr, ack);
 821                 msg_set_bcast_ack(hdr, bc_last_in);
 822
 823                 if (likely(skb_queue_len(transmq) < maxwin)) {
 824                         _skb = skb_clone(skb, GFP_ATOMIC);
 825                         if (!_skb)
 826                                 return -ENOBUFS;
 827                         __skb_dequeue(list);
 828                         __skb_queue_tail(transmq, skb);
 829                         __skb_queue_tail(xmitq, _skb);
 830                         l->rcv_unacked = 0;
 831                         seqno++;
 832                         continue;
 833                 }
 834                 if (tipc_msg_bundle(skb_peek_tail(backlogq), hdr, mtu)) {
 835                         kfree_skb(__skb_dequeue(list));
 836                         l->stats.sent_bundled++;
 837                         continue;
 838                 }
 839                 if (tipc_msg_make_bundle(&bskb, hdr, mtu, l->addr)) {
 840                         kfree_skb(__skb_dequeue(list));
 841                         __skb_queue_tail(backlogq, bskb);
 842                         l->backlog[msg_importance(buf_msg(bskb))].len++;
 843                         l->stats.sent_bundled++;
 844                         l->stats.sent_bundles++;
 845                         continue;
 846                 }
 847                 l->backlog[imp].len += skb_queue_len(list);
 848                 skb_queue_splice_tail_init(list, backlogq);
 849         }
 850         l->snd_nxt = seqno;
 851         return 0;
 852 }
 853
 854 static void skb2list(struct sk_buff *skb, struct sk_buff_head *list)
 855 {
 856         skb_queue_head_init(list);
 857         __skb_queue_tail(list, skb);
 858 }
 859
 860 static int __tipc_link_xmit_skb(struct tipc_link *link, struct sk_buff *skb)
 861 {
 862         struct sk_buff_head head;
 863
 864         skb2list(skb, &head);
 865         return __tipc_link_xmit(link->owner->net, link, &head);
 866 }
 867
 868 /*
 869  * tipc_link_sync_xmit - synchronize broadcast link endpoints.
 870  *
 871  * Give a newly added peer node the sequence number where it should
 872  * start receiving and acking broadcast packets.
 873  *
 874  * Called with node locked
 875  */
 876 static void tipc_link_sync_xmit(struct tipc_link *link)
 877 {
 878         struct sk_buff *skb;
 879         struct tipc_msg *msg;
 880
 881         skb = tipc_buf_acquire(INT_H_SIZE);
 882         if (!skb)
 883                 return;
 884
 885         msg = buf_msg(skb);
 886         tipc_msg_init(link_own_addr(link), msg, BCAST_PROTOCOL, STATE_MSG,
 887                       INT_H_SIZE, link->addr);
 888         msg_set_last_bcast(msg, link->owner->bclink.acked);
 889         __tipc_link_xmit_skb(link, skb);
 890 }
 891
 892 /*
 893  * tipc_link_sync_rcv - synchronize broadcast link endpoints.
 894  * Receive the sequence number where we should start receiving and
 895  * acking broadcast packets from a newly added peer node, and open
 896  * up for reception of such packets.
 897  *
 898  * Called with node locked
 899  */
 900 static void tipc_link_sync_rcv(struct tipc_node *n, struct sk_buff *buf)
 901 {
 902         struct tipc_msg *msg = buf_msg(buf);
 903
 904         n->bclink.last_sent = n->bclink.last_in = msg_last_bcast(msg);
 905         n->bclink.recv_permitted = true;
 906         kfree_skb(buf);
 907 }
 908
 909 /*
 910  * tipc_link_push_packets - push unsent packets to bearer
 911  *
 912  * Push out the unsent messages of a link where congestion
 913  * has abated. Node is locked.
 914  *
 915  * Called with node locked
 916  */
 917 void tipc_link_push_packets(struct tipc_link *link)
 918 {
 919         struct sk_buff *skb;
 920         struct tipc_msg *msg;
 921         u16 seqno = link->snd_nxt;
 922         u16 ack = mod(link->rcv_nxt - 1);
 923
 924         while (skb_queue_len(&link->transmq) < link->window) {
 925                 skb = __skb_dequeue(&link->backlogq);
 926                 if (!skb)
 927                         break;
 928                 msg = buf_msg(skb);
 929                 link->backlog[msg_importance(msg)].len--;
 930                 msg_set_ack(msg, ack);
 931                 msg_set_seqno(msg, seqno);
 932                 seqno = mod(seqno + 1);
 933                 msg_set_bcast_ack(msg, link->owner->bclink.last_in);
 934                 link->rcv_unacked = 0;
 935                 __skb_queue_tail(&link->transmq, skb);
 936                 tipc_bearer_send(link->owner->net, link->bearer_id,
 937                                  skb, &link->media_addr);
 938         }
 939         link->snd_nxt = seqno;
 940 }
 941
 942 void tipc_link_reset_all(struct tipc_node *node)
 943 {
 944         char addr_string[16];
 945         u32 i;
 946
 947         tipc_node_lock(node);
 948
 949         pr_warn("Resetting all links to %s\n",
 950                 tipc_addr_string_fill(addr_string, node->addr));
 951
 952         for (i = 0; i < MAX_BEARERS; i++) {
 953                 if (node->links[i].link) {
 954                         link_print(node->links[i].link, "Resetting link\n");
 955                         tipc_link_reset(node->links[i].link);
 956                 }
 957         }
 958
 959         tipc_node_unlock(node);
 960 }
 961
 962 static void link_retransmit_failure(struct tipc_link *l_ptr,
 963                                     struct sk_buff *buf)
 964 {
 965         struct tipc_msg *msg = buf_msg(buf);
 966         struct net *net = l_ptr->owner->net;
 967
 968         pr_warn("Retransmission failure on link <%s>\n", l_ptr->name);
 969
 970         if (l_ptr->addr) {
 971                 /* Handle failure on standard link */
 972                 link_print(l_ptr, "Resetting link\n");
 973                 tipc_link_reset(l_ptr);
 974
 975         } else {
 976                 /* Handle failure on broadcast link */
 977                 struct tipc_node *n_ptr;
 978                 char addr_string[16];
 979
 980                 pr_info("Msg seq number: %u,  ", msg_seqno(msg));
 981                 pr_cont("Outstanding acks: %lu\n",
 982                         (unsigned long) TIPC_SKB_CB(buf)->handle);
 983
 984                 n_ptr = tipc_bclink_retransmit_to(net);
 985
 986                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 987                 pr_info("Broadcast link info for %s\n", addr_string);
 988                 pr_info("Reception permitted: %d,  Acked: %u\n",
 989                         n_ptr->bclink.recv_permitted,
 990                         n_ptr->bclink.acked);
 991                 pr_info("Last in: %u,  Oos state: %u,  Last sent: %u\n",
 992                         n_ptr->bclink.last_in,
 993                         n_ptr->bclink.oos_state,
 994                         n_ptr->bclink.last_sent);
 995
 996                 n_ptr->action_flags |= TIPC_BCAST_RESET;
 997                 l_ptr->stale_count = 0;
 998         }
 999 }
1000
1001 void tipc_link_retransmit(struct tipc_link *l_ptr, struct sk_buff *skb,
1002                           u32 retransmits)
1003 {
1004         struct tipc_msg *msg;
1005
1006         if (!skb)
1007                 return;
1008
1009         msg = buf_msg(skb);
1010
1011         /* Detect repeated retransmit failures */
1012         if (l_ptr->last_retransm == msg_seqno(msg)) {
1013                 if (++l_ptr->stale_count > 100) {
1014                         link_retransmit_failure(l_ptr, skb);
1015                         return;
1016                 }
1017         } else {
1018                 l_ptr->last_retransm = msg_seqno(msg);
1019                 l_ptr->stale_count = 1;
1020         }
1021
1022         skb_queue_walk_from(&l_ptr->transmq, skb) {
1023                 if (!retransmits)
1024                         break;
1025                 msg = buf_msg(skb);
1026                 msg_set_ack(msg, mod(l_ptr->rcv_nxt - 1));
1027                 msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1028                 tipc_bearer_send(l_ptr->owner->net, l_ptr->bearer_id, skb,
1029                                  &l_ptr->media_addr);
1030                 retransmits--;
1031                 l_ptr->stats.retransmitted++;
1032         }
1033 }
1034
1035 /* link_synch(): check if all packets arrived before the synch
1036  *               point have been consumed
1037  * Returns true if the parallel links are synched, otherwise false
1038  */
1039 static bool link_synch(struct tipc_link *l)
1040 {
1041         unsigned int post_synch;
1042         struct tipc_link *pl;
1043
1044         pl  = tipc_parallel_link(l);
1045         if (pl == l)
1046                 goto synched;
1047
1048         /* Was last pre-synch packet added to input queue ? */
1049         if (less_eq(pl->rcv_nxt, l->synch_point))
1050                 return false;
1051
1052         /* Is it still in the input queue ? */
1053         post_synch = mod(pl->rcv_nxt - l->synch_point) - 1;
1054         if (skb_queue_len(pl->inputq) > post_synch)
1055                 return false;
1056 synched:
1057         l->exec_mode = TIPC_LINK_OPEN;
1058         return true;
1059 }
1060
1061 static void link_retrieve_defq(struct tipc_link *link,
1062                                struct sk_buff_head *list)
1063 {
1064         u16 seq_no;
1065
1066         if (skb_queue_empty(&link->deferdq))
1067                 return;
1068
1069         seq_no = buf_seqno(skb_peek(&link->deferdq));
1070         if (seq_no == link->rcv_nxt)
1071                 skb_queue_splice_tail_init(&link->deferdq, list);
1072 }
1073
1074 /**
1075  * tipc_rcv - process TIPC packets/messages arriving from off-node
1076  * @net: the applicable net namespace
1077  * @skb: TIPC packet
1078  * @b_ptr: pointer to bearer message arrived on
1079  *
1080  * Invoked with no locks held.  Bearer pointer must point to a valid bearer
1081  * structure (i.e. cannot be NULL), but bearer can be inactive.
1082  */
1083 void tipc_rcv(struct net *net, struct sk_buff *skb, struct tipc_bearer *b_ptr)
1084 {
1085         struct tipc_net *tn = net_generic(net, tipc_net_id);
1086         struct sk_buff_head head;
1087         struct tipc_node *n_ptr;
1088         struct tipc_link *l_ptr;
1089         struct sk_buff *skb1, *tmp;
1090         struct tipc_msg *msg;
1091         u16 seq_no;
1092         u16 ackd;
1093         u32 released;
1094
1095         skb2list(skb, &head);
1096
1097         while ((skb = __skb_dequeue(&head))) {
1098                 /* Ensure message is well-formed */
1099                 if (unlikely(!tipc_msg_validate(skb)))
1100                         goto discard;
1101
1102                 /* Handle arrival of a non-unicast link message */
1103                 msg = buf_msg(skb);
1104                 if (unlikely(msg_non_seq(msg))) {
1105                         if (msg_user(msg) ==  LINK_CONFIG)
1106                                 tipc_disc_rcv(net, skb, b_ptr);
1107                         else
1108                                 tipc_bclink_rcv(net, skb);
1109                         continue;
1110                 }
1111
1112                 /* Discard unicast link messages destined for another node */
1113                 if (unlikely(!msg_short(msg) &&
1114                              (msg_destnode(msg) != tn->own_addr)))
1115                         goto discard;
1116
1117                 /* Locate neighboring node that sent message */
1118                 n_ptr = tipc_node_find(net, msg_prevnode(msg));
1119                 if (unlikely(!n_ptr))
1120                         goto discard;
1121
1122                 tipc_node_lock(n_ptr);
1123                 /* Locate unicast link endpoint that should handle message */
1124                 l_ptr = n_ptr->links[b_ptr->identity].link;
1125                 if (unlikely(!l_ptr))
1126                         goto unlock;
1127
1128                 /* Verify that communication with node is currently allowed */
1129                 if ((n_ptr->action_flags & TIPC_WAIT_PEER_LINKS_DOWN) &&
1130                     msg_user(msg) == LINK_PROTOCOL &&
1131                     (msg_type(msg) == RESET_MSG ||
1132                     msg_type(msg) == ACTIVATE_MSG) &&
1133                     !msg_redundant_link(msg))
1134                         n_ptr->action_flags &= ~TIPC_WAIT_PEER_LINKS_DOWN;
1135
1136                 if (tipc_node_blocked(n_ptr))
1137                         goto unlock;
1138
1139                 /* Validate message sequence number info */
1140                 seq_no = msg_seqno(msg);
1141                 ackd = msg_ack(msg);
1142
1143                 /* Release acked messages */
1144                 if (unlikely(n_ptr->bclink.acked != msg_bcast_ack(msg)))
1145                         tipc_bclink_acknowledge(n_ptr, msg_bcast_ack(msg));
1146
1147                 released = 0;
1148                 skb_queue_walk_safe(&l_ptr->transmq, skb1, tmp) {
1149                         if (more(buf_seqno(skb1), ackd))
1150                                 break;
1151                          __skb_unlink(skb1, &l_ptr->transmq);
1152                          kfree_skb(skb1);
1153                          released = 1;
1154                 }
1155
1156                 /* Try sending any messages link endpoint has pending */
1157                 if (unlikely(skb_queue_len(&l_ptr->backlogq)))
1158                         tipc_link_push_packets(l_ptr);
1159
1160                 if (released && !skb_queue_empty(&l_ptr->wakeupq))
1161                         link_prepare_wakeup(l_ptr);
1162
1163                 /* Process the incoming packet */
1164                 if (unlikely(!link_working(l_ptr))) {
1165                         if (msg_user(msg) == LINK_PROTOCOL) {
1166                                 tipc_link_proto_rcv(l_ptr, skb);
1167                                 link_retrieve_defq(l_ptr, &head);
1168                                 skb = NULL;
1169                                 goto unlock;
1170                         }
1171
1172                         /* Traffic message. Conditionally activate link */
1173                         link_state_event(l_ptr, TRAFFIC_EVT);
1174
1175                         if (link_working(l_ptr)) {
1176                                 /* Re-insert buffer in front of queue */
1177                                 __skb_queue_head(&head, skb);
1178                                 skb = NULL;
1179                                 goto unlock;
1180                         }
1181                         goto unlock;
1182                 }
1183
1184                 /* Link is now in state TIPC_LINK_WORKING */
1185                 if (unlikely(seq_no != l_ptr->rcv_nxt)) {
1186                         link_handle_out_of_seq_msg(l_ptr, skb);
1187                         link_retrieve_defq(l_ptr, &head);
1188                         skb = NULL;
1189                         goto unlock;
1190                 }
1191                 l_ptr->silent_intv_cnt = 0;
1192
1193                 /* Synchronize with parallel link if applicable */
1194                 if (unlikely((l_ptr->exec_mode == TIPC_LINK_TUNNEL) &&
1195                              !msg_dup(msg))) {
1196                         if (!link_synch(l_ptr))
1197                                 goto unlock;
1198                 }
1199                 l_ptr->rcv_nxt++;
1200                 if (unlikely(!skb_queue_empty(&l_ptr->deferdq)))
1201                         link_retrieve_defq(l_ptr, &head);
1202                 if (unlikely(++l_ptr->rcv_unacked >= TIPC_MIN_LINK_WIN)) {
1203                         l_ptr->stats.sent_acks++;
1204                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, 0, 0, 0);
1205                 }
1206                 tipc_link_input(l_ptr, skb);
1207                 skb = NULL;
1208 unlock:
1209                 tipc_node_unlock(n_ptr);
1210                 tipc_node_put(n_ptr);
1211 discard:
1212                 if (unlikely(skb))
1213                         kfree_skb(skb);
1214         }
1215 }
1216
1217 /* tipc_data_input - deliver data and name distr msgs to upper layer
1218  *
1219  * Consumes buffer if message is of right type
1220  * Node lock must be held
1221  */
1222 static bool tipc_data_input(struct tipc_link *link, struct sk_buff *skb)
1223 {
1224         struct tipc_node *node = link->owner;
1225         struct tipc_msg *msg = buf_msg(skb);
1226         u32 dport = msg_destport(msg);
1227
1228         switch (msg_user(msg)) {
1229         case TIPC_LOW_IMPORTANCE:
1230         case TIPC_MEDIUM_IMPORTANCE:
1231         case TIPC_HIGH_IMPORTANCE:
1232         case TIPC_CRITICAL_IMPORTANCE:
1233         case CONN_MANAGER:
1234                 if (tipc_skb_queue_tail(link->inputq, skb, dport)) {
1235                         node->inputq = link->inputq;
1236                         node->action_flags |= TIPC_MSG_EVT;
1237                 }
1238                 return true;
1239         case NAME_DISTRIBUTOR:
1240                 node->bclink.recv_permitted = true;
1241                 node->namedq = link->namedq;
1242                 skb_queue_tail(link->namedq, skb);
1243                 if (skb_queue_len(link->namedq) == 1)
1244                         node->action_flags |= TIPC_NAMED_MSG_EVT;
1245                 return true;
1246         case MSG_BUNDLER:
1247         case TUNNEL_PROTOCOL:
1248         case MSG_FRAGMENTER:
1249         case BCAST_PROTOCOL:
1250                 return false;
1251         default:
1252                 pr_warn("Dropping received illegal msg type\n");
1253                 kfree_skb(skb);
1254                 return false;
1255         };
1256 }
1257
1258 /* tipc_link_input - process packet that has passed link protocol check
1259  *
1260  * Consumes buffer
1261  * Node lock must be held
1262  */
1263 static void tipc_link_input(struct tipc_link *link, struct sk_buff *skb)
1264 {
1265         struct tipc_node *node = link->owner;
1266         struct tipc_msg *msg = buf_msg(skb);
1267         struct sk_buff *iskb;
1268         int pos = 0;
1269
1270         if (likely(tipc_data_input(link, skb)))
1271                 return;
1272
1273         switch (msg_user(msg)) {
1274         case TUNNEL_PROTOCOL:
1275                 if (msg_dup(msg)) {
1276                         link->exec_mode = TIPC_LINK_TUNNEL;
1277                         link->synch_point = msg_seqno(msg_get_wrapped(msg));
1278                         kfree_skb(skb);
1279                         break;
1280                 }
1281                 if (!tipc_link_failover_rcv(link, &skb))
1282                         break;
1283                 if (msg_user(buf_msg(skb)) != MSG_BUNDLER) {
1284                         tipc_data_input(link, skb);
1285                         break;
1286                 }
1287         case MSG_BUNDLER:
1288                 link->stats.recv_bundles++;
1289                 link->stats.recv_bundled += msg_msgcnt(msg);
1290
1291                 while (tipc_msg_extract(skb, &iskb, &pos))
1292                         tipc_data_input(link, iskb);
1293                 break;
1294         case MSG_FRAGMENTER:
1295                 link->stats.recv_fragments++;
1296                 if (tipc_buf_append(&link->reasm_buf, &skb)) {
1297                         link->stats.recv_fragmented++;
1298                         tipc_data_input(link, skb);
1299                 } else if (!link->reasm_buf) {
1300                         tipc_link_reset(link);
1301                 }
1302                 break;
1303         case BCAST_PROTOCOL:
1304                 tipc_link_sync_rcv(node, skb);
1305                 break;
1306         default:
1307                 break;
1308         };
1309 }
1310
1311 /**
1312  * tipc_link_defer_pkt - Add out-of-sequence message to deferred reception queue
1313  *
1314  * Returns increase in queue length (i.e. 0 or 1)
1315  */
1316 u32 tipc_link_defer_pkt(struct sk_buff_head *list, struct sk_buff *skb)
1317 {
1318         struct sk_buff *skb1;
1319         u16 seq_no = buf_seqno(skb);
1320
1321         /* Empty queue ? */
1322         if (skb_queue_empty(list)) {
1323                 __skb_queue_tail(list, skb);
1324                 return 1;
1325         }
1326
1327         /* Last ? */
1328         if (less(buf_seqno(skb_peek_tail(list)), seq_no)) {
1329                 __skb_queue_tail(list, skb);
1330                 return 1;
1331         }
1332
1333         /* Locate insertion point in queue, then insert; discard if duplicate */
1334         skb_queue_walk(list, skb1) {
1335                 u16 curr_seqno = buf_seqno(skb1);
1336
1337                 if (seq_no == curr_seqno) {
1338                         kfree_skb(skb);
1339                         return 0;
1340                 }
1341
1342                 if (less(seq_no, curr_seqno))
1343                         break;
1344         }
1345
1346         __skb_queue_before(list, skb1, skb);
1347         return 1;
1348 }
1349
1350 /*
1351  * link_handle_out_of_seq_msg - handle arrival of out-of-sequence packet
1352  */
1353 static void link_handle_out_of_seq_msg(struct tipc_link *l_ptr,
1354                                        struct sk_buff *buf)
1355 {
1356         u32 seq_no = buf_seqno(buf);
1357
1358         if (likely(msg_user(buf_msg(buf)) == LINK_PROTOCOL)) {
1359                 tipc_link_proto_rcv(l_ptr, buf);
1360                 return;
1361         }
1362
1363         /* Record OOS packet arrival */
1364         l_ptr->silent_intv_cnt = 0;
1365
1366         /*
1367          * Discard packet if a duplicate; otherwise add it to deferred queue
1368          * and notify peer of gap as per protocol specification
1369          */
1370         if (less(seq_no, l_ptr->rcv_nxt)) {
1371                 l_ptr->stats.duplicates++;
1372                 kfree_skb(buf);
1373                 return;
1374         }
1375
1376         if (tipc_link_defer_pkt(&l_ptr->deferdq, buf)) {
1377                 l_ptr->stats.deferred_recv++;
1378                 if ((skb_queue_len(&l_ptr->deferdq) % TIPC_MIN_LINK_WIN) == 1)
1379                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, 0, 0, 0);
1380         } else {
1381                 l_ptr->stats.duplicates++;
1382         }
1383 }
1384
1385 /*
1386  * Send protocol message to the other endpoint.
1387  */
1388 void tipc_link_proto_xmit(struct tipc_link *l, u32 msg_typ, int probe_msg,
1389                           u32 gap, u32 tolerance, u32 priority)
1390 {
1391         struct sk_buff *skb = NULL;
1392         struct sk_buff_head xmitq;
1393
1394         __skb_queue_head_init(&xmitq);
1395         tipc_link_build_proto_msg(l, msg_typ, probe_msg, gap,
1396                                   tolerance, priority, &xmitq);
1397         skb = __skb_dequeue(&xmitq);
1398         if (!skb)
1399                 return;
1400         tipc_bearer_send(l->owner->net, l->bearer_id, skb, &l->media_addr);
1401         l->rcv_unacked = 0;
1402         kfree_skb(skb);
1403 }
1404
1405 /*
1406  * Receive protocol message :
1407  * Note that network plane id propagates through the network, and may
1408  * change at any time. The node with lowest address rules
1409  */
1410 static void tipc_link_proto_rcv(struct tipc_link *l_ptr,
1411                                 struct sk_buff *buf)
1412 {
1413         u32 rec_gap = 0;
1414         u32 msg_tol;
1415         struct tipc_msg *msg = buf_msg(buf);
1416
1417         if (l_ptr->exec_mode == TIPC_LINK_BLOCKED)
1418                 goto exit;
1419
1420         if (l_ptr->net_plane != msg_net_plane(msg))
1421                 if (link_own_addr(l_ptr) > msg_prevnode(msg))
1422                         l_ptr->net_plane = msg_net_plane(msg);
1423
1424         switch (msg_type(msg)) {
1425
1426         case RESET_MSG:
1427                 if (!link_probing(l_ptr) &&
1428                     (l_ptr->peer_session != WILDCARD_SESSION)) {
1429                         if (less_eq(msg_session(msg), l_ptr->peer_session))
1430                                 break; /* duplicate or old reset: ignore */
1431                 }
1432
1433                 if (!msg_redundant_link(msg) && (link_working(l_ptr) ||
1434                                                  link_probing(l_ptr))) {
1435                         /* peer has lost contact -- don't allow peer's links
1436                          * to reactivate before we recognize loss & clean up
1437                          */
1438                         l_ptr->owner->action_flags |= TIPC_WAIT_OWN_LINKS_DOWN;
1439                 }
1440
1441                 link_state_event(l_ptr, RESET_MSG);
1442
1443                 /* fall thru' */
1444         case ACTIVATE_MSG:
1445                 /* Update link settings according other endpoint's values */
1446                 strcpy((strrchr(l_ptr->name, ':') + 1), (char *)msg_data(msg));
1447
1448                 msg_tol = msg_link_tolerance(msg);
1449                 if (msg_tol > l_ptr->tolerance)
1450                         link_set_supervision_props(l_ptr, msg_tol);
1451
1452                 if (msg_linkprio(msg) > l_ptr->priority)
1453                         l_ptr->priority = msg_linkprio(msg);
1454
1455                 if (l_ptr->mtu > msg_max_pkt(msg))
1456                         l_ptr->mtu = msg_max_pkt(msg);
1457
1458                 /* Synchronize broadcast link info, if not done previously */
1459                 if (!tipc_node_is_up(l_ptr->owner)) {
1460                         l_ptr->owner->bclink.last_sent =
1461                                 l_ptr->owner->bclink.last_in =
1462                                 msg_last_bcast(msg);
1463                         l_ptr->owner->bclink.oos_state = 0;
1464                 }
1465
1466                 l_ptr->peer_session = msg_session(msg);
1467                 l_ptr->peer_bearer_id = msg_bearer_id(msg);
1468
1469                 if (msg_type(msg) == ACTIVATE_MSG)
1470                         link_state_event(l_ptr, ACTIVATE_MSG);
1471                 break;
1472         case STATE_MSG:
1473
1474                 msg_tol = msg_link_tolerance(msg);
1475                 if (msg_tol)
1476                         link_set_supervision_props(l_ptr, msg_tol);
1477
1478                 if (msg_linkprio(msg) &&
1479                     (msg_linkprio(msg) != l_ptr->priority)) {
1480                         pr_debug("%s<%s>, priority change %u->%u\n",
1481                                  link_rst_msg, l_ptr->name,
1482                                  l_ptr->priority, msg_linkprio(msg));
1483                         l_ptr->priority = msg_linkprio(msg);
1484                         tipc_link_reset(l_ptr); /* Enforce change to take effect */
1485                         break;
1486                 }
1487
1488                 /* Record reception; force mismatch at next timeout: */
1489                 l_ptr->silent_intv_cnt = 0;
1490
1491                 link_state_event(l_ptr, TRAFFIC_EVT);
1492                 l_ptr->stats.recv_states++;
1493                 if (link_resetting(l_ptr))
1494                         break;
1495
1496                 if (less_eq(l_ptr->rcv_nxt, msg_next_sent(msg)))
1497                         rec_gap = mod(msg_next_sent(msg) - l_ptr->rcv_nxt);
1498
1499                 if (msg_probe(msg))
1500                         l_ptr->stats.recv_probes++;
1501
1502                 /* Protocol message before retransmits, reduce loss risk */
1503                 if (l_ptr->owner->bclink.recv_permitted)
1504                         tipc_bclink_update_link_state(l_ptr->owner,
1505                                                       msg_last_bcast(msg));
1506
1507                 if (rec_gap || (msg_probe(msg))) {
1508                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 0,
1509                                              rec_gap, 0, 0);
1510                 }
1511                 if (msg_seq_gap(msg)) {
1512                         l_ptr->stats.recv_nacks++;
1513                         tipc_link_retransmit(l_ptr, skb_peek(&l_ptr->transmq),
1514                                              msg_seq_gap(msg));
1515                 }
1516                 break;
1517         }
1518 exit:
1519         kfree_skb(buf);
1520 }
1521
1522 /* tipc_link_build_proto_msg: prepare link protocol message for transmission
1523  */
1524 static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
1525                                       u16 rcvgap, int tolerance, int priority,
1526                                       struct sk_buff_head *xmitq)
1527 {
1528         struct sk_buff *skb = NULL;
1529         struct tipc_msg *hdr = l->pmsg;
1530         u16 snd_nxt = l->snd_nxt;
1531         u16 rcv_nxt = l->rcv_nxt;
1532         u16 rcv_last = rcv_nxt - 1;
1533         int node_up = l->owner->bclink.recv_permitted;
1534
1535         /* Don't send protocol message during reset or link failover */
1536         if (l->exec_mode == TIPC_LINK_BLOCKED)
1537                 return;
1538
1539         /* Abort non-RESET send if communication with node is prohibited */
1540         if ((tipc_node_blocked(l->owner)) && (mtyp != RESET_MSG))
1541                 return;
1542
1543         msg_set_type(hdr, mtyp);
1544         msg_set_net_plane(hdr, l->net_plane);
1545         msg_set_bcast_ack(hdr, l->owner->bclink.last_in);
1546         msg_set_last_bcast(hdr, tipc_bclink_get_last_sent(l->owner->net));
1547         msg_set_link_tolerance(hdr, tolerance);
1548         msg_set_linkprio(hdr, priority);
1549         msg_set_redundant_link(hdr, node_up);
1550         msg_set_seq_gap(hdr, 0);
1551
1552         /* Compatibility: created msg must not be in sequence with pkt flow */
1553         msg_set_seqno(hdr, snd_nxt + U16_MAX / 2);
1554
1555         if (mtyp == STATE_MSG) {
1556                 if (!tipc_link_is_up(l))
1557                         return;
1558                 msg_set_next_sent(hdr, snd_nxt);
1559
1560                 /* Override rcvgap if there are packets in deferred queue */
1561                 if (!skb_queue_empty(&l->deferdq))
1562                         rcvgap = buf_seqno(skb_peek(&l->deferdq)) - rcv_nxt;
1563                 if (rcvgap) {
1564                         msg_set_seq_gap(hdr, rcvgap);
1565                         l->stats.sent_nacks++;
1566                 }
1567                 msg_set_ack(hdr, rcv_last);
1568                 msg_set_probe(hdr, probe);
1569                 if (probe)
1570                         l->stats.sent_probes++;
1571                 l->stats.sent_states++;
1572         } else {
1573                 /* RESET_MSG or ACTIVATE_MSG */
1574                 msg_set_max_pkt(hdr, l->advertised_mtu);
1575                 msg_set_ack(hdr, l->failover_checkpt - 1);
1576                 msg_set_next_sent(hdr, 1);
1577         }
1578         skb = tipc_buf_acquire(msg_size(hdr));
1579         if (!skb)
1580                 return;
1581         skb_copy_to_linear_data(skb, hdr, msg_size(hdr));
1582         skb->priority = TC_PRIO_CONTROL;
1583         __skb_queue_head(xmitq, skb);
1584 }
1585
1586 /* tipc_link_tunnel_xmit(): Tunnel one packet via a link belonging to
1587  * a different bearer. Owner node is locked.
1588  */
1589 static void tipc_link_tunnel_xmit(struct tipc_link *l_ptr,
1590                                   struct tipc_msg *tunnel_hdr,
1591                                   struct tipc_msg *msg,
1592                                   u32 selector)
1593 {
1594         struct tipc_link *tunnel;
1595         struct sk_buff *skb;
1596         u32 length = msg_size(msg);
1597
1598         tunnel = node_active_link(l_ptr->owner, selector & 1);
1599         if (!tipc_link_is_up(tunnel)) {
1600                 pr_warn("%stunnel link no longer available\n", link_co_err);
1601                 return;
1602         }
1603         msg_set_size(tunnel_hdr, length + INT_H_SIZE);
1604         skb = tipc_buf_acquire(length + INT_H_SIZE);
1605         if (!skb) {
1606                 pr_warn("%sunable to send tunnel msg\n", link_co_err);
1607                 return;
1608         }
1609         skb_copy_to_linear_data(skb, tunnel_hdr, INT_H_SIZE);
1610         skb_copy_to_linear_data_offset(skb, INT_H_SIZE, msg, length);
1611         __tipc_link_xmit_skb(tunnel, skb);
1612 }
1613
1614
1615 /* tipc_link_failover_send_queue(): A link has gone down, but a second
1616  * link is still active. We can do failover. Tunnel the failing link's
1617  * whole send queue via the remaining link. This way, we don't lose
1618  * any packets, and sequence order is preserved for subsequent traffic
1619  * sent over the remaining link. Owner node is locked.
1620  */
1621 void tipc_link_failover_send_queue(struct tipc_link *l_ptr)
1622 {
1623         int msgcount;
1624         struct tipc_link *tunnel = node_active_link(l_ptr->owner, 0);
1625         struct tipc_msg tunnel_hdr;
1626         struct sk_buff *skb;
1627         int split_bundles;
1628
1629         if (!tunnel)
1630                 return;
1631
1632         tipc_msg_init(link_own_addr(l_ptr), &tunnel_hdr, TUNNEL_PROTOCOL,
1633                       FAILOVER_MSG, INT_H_SIZE, l_ptr->addr);
1634
1635         skb_queue_walk(&l_ptr->backlogq, skb) {
1636                 msg_set_seqno(buf_msg(skb), l_ptr->snd_nxt);
1637                 l_ptr->snd_nxt = mod(l_ptr->snd_nxt + 1);
1638         }
1639         skb_queue_splice_tail_init(&l_ptr->backlogq, &l_ptr->transmq);
1640         tipc_link_purge_backlog(l_ptr);
1641         msgcount = skb_queue_len(&l_ptr->transmq);
1642         msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
1643         msg_set_msgcnt(&tunnel_hdr, msgcount);
1644
1645         if (skb_queue_empty(&l_ptr->transmq)) {
1646                 skb = tipc_buf_acquire(INT_H_SIZE);
1647                 if (skb) {
1648                         skb_copy_to_linear_data(skb, &tunnel_hdr, INT_H_SIZE);
1649                         msg_set_size(&tunnel_hdr, INT_H_SIZE);
1650                         __tipc_link_xmit_skb(tunnel, skb);
1651                 } else {
1652                         pr_warn("%sunable to send changeover msg\n",
1653                                 link_co_err);
1654                 }
1655                 return;
1656         }
1657
1658         split_bundles = (node_active_link(l_ptr->owner, 0) !=
1659                          node_active_link(l_ptr->owner, 0));
1660
1661         skb_queue_walk(&l_ptr->transmq, skb) {
1662                 struct tipc_msg *msg = buf_msg(skb);
1663
1664                 if ((msg_user(msg) == MSG_BUNDLER) && split_bundles) {
1665                         struct tipc_msg *m = msg_get_wrapped(msg);
1666                         unchar *pos = (unchar *)m;
1667
1668                         msgcount = msg_msgcnt(msg);
1669                         while (msgcount--) {
1670                                 msg_set_seqno(m, msg_seqno(msg));
1671                                 tipc_link_tunnel_xmit(l_ptr, &tunnel_hdr, m,
1672                                                       msg_link_selector(m));
1673                                 pos += align(msg_size(m));
1674                                 m = (struct tipc_msg *)pos;
1675                         }
1676                 } else {
1677                         tipc_link_tunnel_xmit(l_ptr, &tunnel_hdr, msg,
1678                                               msg_link_selector(msg));
1679                 }
1680         }
1681 }
1682
1683 /* tipc_link_dup_queue_xmit(): A second link has become active. Tunnel a
1684  * duplicate of the first link's send queue via the new link. This way, we
1685  * are guaranteed that currently queued packets from a socket are delivered
1686  * before future traffic from the same socket, even if this is using the
1687  * new link. The last arriving copy of each duplicate packet is dropped at
1688  * the receiving end by the regular protocol check, so packet cardinality
1689  * and sequence order is preserved per sender/receiver socket pair.
1690  * Owner node is locked.
1691  */
1692 void tipc_link_dup_queue_xmit(struct tipc_link *link,
1693                               struct tipc_link *tnl)
1694 {
1695         struct sk_buff *skb;
1696         struct tipc_msg tnl_hdr;
1697         struct sk_buff_head *queue = &link->transmq;
1698         int mcnt;
1699         u16 seqno;
1700
1701         tipc_msg_init(link_own_addr(link), &tnl_hdr, TUNNEL_PROTOCOL,
1702                       SYNCH_MSG, INT_H_SIZE, link->addr);
1703         mcnt = skb_queue_len(&link->transmq) + skb_queue_len(&link->backlogq);
1704         msg_set_msgcnt(&tnl_hdr, mcnt);
1705         msg_set_bearer_id(&tnl_hdr, link->peer_bearer_id);
1706
1707 tunnel_queue:
1708         skb_queue_walk(queue, skb) {
1709                 struct sk_buff *outskb;
1710                 struct tipc_msg *msg = buf_msg(skb);
1711                 u32 len = msg_size(msg);
1712
1713                 msg_set_ack(msg, mod(link->rcv_nxt - 1));
1714                 msg_set_bcast_ack(msg, link->owner->bclink.last_in);
1715                 msg_set_size(&tnl_hdr, len + INT_H_SIZE);
1716                 outskb = tipc_buf_acquire(len + INT_H_SIZE);
1717                 if (outskb == NULL) {
1718                         pr_warn("%sunable to send duplicate msg\n",
1719                                 link_co_err);
1720                         return;
1721                 }
1722                 skb_copy_to_linear_data(outskb, &tnl_hdr, INT_H_SIZE);
1723                 skb_copy_to_linear_data_offset(outskb, INT_H_SIZE,
1724                                                skb->data, len);
1725                 __tipc_link_xmit_skb(tnl, outskb);
1726                 if (!tipc_link_is_up(link))
1727                         return;
1728         }
1729         if (queue == &link->backlogq)
1730                 return;
1731         seqno = link->snd_nxt;
1732         skb_queue_walk(&link->backlogq, skb) {
1733                 msg_set_seqno(buf_msg(skb), seqno);
1734                 seqno = mod(seqno + 1);
1735         }
1736         queue = &link->backlogq;
1737         goto tunnel_queue;
1738 }
1739
1740 /*  tipc_link_failover_rcv(): Receive a tunnelled FAILOVER_MSG packet
1741  *  Owner node is locked.
1742  */
1743 static bool tipc_link_failover_rcv(struct tipc_link *link,
1744                                    struct sk_buff **skb)
1745 {
1746         struct tipc_msg *msg = buf_msg(*skb);
1747         struct sk_buff *iskb = NULL;
1748         struct tipc_link *pl = NULL;
1749         int bearer_id = msg_bearer_id(msg);
1750         int pos = 0;
1751
1752         if (msg_type(msg) != FAILOVER_MSG) {
1753                 pr_warn("%sunknown tunnel pkt received\n", link_co_err);
1754                 goto exit;
1755         }
1756         if (bearer_id >= MAX_BEARERS)
1757                 goto exit;
1758
1759         if (bearer_id == link->bearer_id)
1760                 goto exit;
1761
1762         pl = link->owner->links[bearer_id].link;
1763         if (pl && tipc_link_is_up(pl))
1764                 tipc_link_reset(pl);
1765
1766         if (link->failover_pkts == FIRST_FAILOVER)
1767                 link->failover_pkts = msg_msgcnt(msg);
1768
1769         /* Should we expect an inner packet? */
1770         if (!link->failover_pkts)
1771                 goto exit;
1772
1773         if (!tipc_msg_extract(*skb, &iskb, &pos)) {
1774                 pr_warn("%sno inner failover pkt\n", link_co_err);
1775                 *skb = NULL;
1776                 goto exit;
1777         }
1778         link->failover_pkts--;
1779         *skb = NULL;
1780
1781         /* Was this packet already delivered? */
1782         if (less(buf_seqno(iskb), link->failover_checkpt)) {
1783                 kfree_skb(iskb);
1784                 iskb = NULL;
1785                 goto exit;
1786         }
1787         if (msg_user(buf_msg(iskb)) == MSG_FRAGMENTER) {
1788                 link->stats.recv_fragments++;
1789                 tipc_buf_append(&link->failover_skb, &iskb);
1790         }
1791 exit:
1792         if (!link->failover_pkts && pl)
1793                 pl->exec_mode = TIPC_LINK_OPEN;
1794         kfree_skb(*skb);
1795         *skb = iskb;
1796         return *skb;
1797 }
1798
1799 static void link_set_supervision_props(struct tipc_link *l_ptr, u32 tol)
1800 {
1801         unsigned long intv = ((tol / 4) > 500) ? 500 : tol / 4;
1802
1803         if ((tol < TIPC_MIN_LINK_TOL) || (tol > TIPC_MAX_LINK_TOL))
1804                 return;
1805
1806         l_ptr->tolerance = tol;
1807         l_ptr->keepalive_intv = msecs_to_jiffies(intv);
1808         l_ptr->abort_limit = tol / (jiffies_to_msecs(l_ptr->keepalive_intv));
1809 }
1810
1811 void tipc_link_set_queue_limits(struct tipc_link *l, u32 win)
1812 {
1813         int max_bulk = TIPC_MAX_PUBLICATIONS / (l->mtu / ITEM_SIZE);
1814
1815         l->window = win;
1816         l->backlog[TIPC_LOW_IMPORTANCE].limit      = win / 2;
1817         l->backlog[TIPC_MEDIUM_IMPORTANCE].limit   = win;
1818         l->backlog[TIPC_HIGH_IMPORTANCE].limit     = win / 2 * 3;
1819         l->backlog[TIPC_CRITICAL_IMPORTANCE].limit = win * 2;
1820         l->backlog[TIPC_SYSTEM_IMPORTANCE].limit   = max_bulk;
1821 }
1822
1823 /* tipc_link_find_owner - locate owner node of link by link's name
1824  * @net: the applicable net namespace
1825  * @name: pointer to link name string
1826  * @bearer_id: pointer to index in 'node->links' array where the link was found.
1827  *
1828  * Returns pointer to node owning the link, or 0 if no matching link is found.
1829  */
1830 static struct tipc_node *tipc_link_find_owner(struct net *net,
1831                                               const char *link_name,
1832                                               unsigned int *bearer_id)
1833 {
1834         struct tipc_net *tn = net_generic(net, tipc_net_id);
1835         struct tipc_link *l_ptr;
1836         struct tipc_node *n_ptr;
1837         struct tipc_node *found_node = NULL;
1838         int i;
1839
1840         *bearer_id = 0;
1841         rcu_read_lock();
1842         list_for_each_entry_rcu(n_ptr, &tn->node_list, list) {
1843                 tipc_node_lock(n_ptr);
1844                 for (i = 0; i < MAX_BEARERS; i++) {
1845                         l_ptr = n_ptr->links[i].link;
1846                         if (l_ptr && !strcmp(l_ptr->name, link_name)) {
1847                                 *bearer_id = i;
1848                                 found_node = n_ptr;
1849                                 break;
1850                         }
1851                 }
1852                 tipc_node_unlock(n_ptr);
1853                 if (found_node)
1854                         break;
1855         }
1856         rcu_read_unlock();
1857
1858         return found_node;
1859 }
1860
1861 /**
1862  * link_reset_statistics - reset link statistics
1863  * @l_ptr: pointer to link
1864  */
1865 static void link_reset_statistics(struct tipc_link *l_ptr)
1866 {
1867         memset(&l_ptr->stats, 0, sizeof(l_ptr->stats));
1868         l_ptr->stats.sent_info = l_ptr->snd_nxt;
1869         l_ptr->stats.recv_info = l_ptr->rcv_nxt;
1870 }
1871
1872 static void link_print(struct tipc_link *l_ptr, const char *str)
1873 {
1874         struct tipc_net *tn = net_generic(l_ptr->owner->net, tipc_net_id);
1875         struct tipc_bearer *b_ptr;
1876
1877         rcu_read_lock();
1878         b_ptr = rcu_dereference_rtnl(tn->bearer_list[l_ptr->bearer_id]);
1879         if (b_ptr)
1880                 pr_info("%s Link %x<%s>:", str, l_ptr->addr, b_ptr->name);
1881         rcu_read_unlock();
1882
1883         if (link_probing(l_ptr))
1884                 pr_cont(":P\n");
1885         else if (link_establishing(l_ptr))
1886                 pr_cont(":E\n");
1887         else if (link_resetting(l_ptr))
1888                 pr_cont(":R\n");
1889         else if (link_working(l_ptr))
1890                 pr_cont(":W\n");
1891         else
1892                 pr_cont("\n");
1893 }
1894
1895 /* Parse and validate nested (link) properties valid for media, bearer and link
1896  */
1897 int tipc_nl_parse_link_prop(struct nlattr *prop, struct nlattr *props[])
1898 {
1899         int err;
1900
1901         err = nla_parse_nested(props, TIPC_NLA_PROP_MAX, prop,
1902                                tipc_nl_prop_policy);
1903         if (err)
1904                 return err;
1905
1906         if (props[TIPC_NLA_PROP_PRIO]) {
1907                 u32 prio;
1908
1909                 prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
1910                 if (prio > TIPC_MAX_LINK_PRI)
1911                         return -EINVAL;
1912         }
1913
1914         if (props[TIPC_NLA_PROP_TOL]) {
1915                 u32 tol;
1916
1917                 tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
1918                 if ((tol < TIPC_MIN_LINK_TOL) || (tol > TIPC_MAX_LINK_TOL))
1919                         return -EINVAL;
1920         }
1921
1922         if (props[TIPC_NLA_PROP_WIN]) {
1923                 u32 win;
1924
1925                 win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
1926                 if ((win < TIPC_MIN_LINK_WIN) || (win > TIPC_MAX_LINK_WIN))
1927                         return -EINVAL;
1928         }
1929
1930         return 0;
1931 }
1932
1933 int tipc_nl_link_set(struct sk_buff *skb, struct genl_info *info)
1934 {
1935         int err;
1936         int res = 0;
1937         int bearer_id;
1938         char *name;
1939         struct tipc_link *link;
1940         struct tipc_node *node;
1941         struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
1942         struct net *net = sock_net(skb->sk);
1943
1944         if (!info->attrs[TIPC_NLA_LINK])
1945                 return -EINVAL;
1946
1947         err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
1948                                info->attrs[TIPC_NLA_LINK],
1949                                tipc_nl_link_policy);
1950         if (err)
1951                 return err;
1952
1953         if (!attrs[TIPC_NLA_LINK_NAME])
1954                 return -EINVAL;
1955
1956         name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
1957
1958         if (strcmp(name, tipc_bclink_name) == 0)
1959                 return tipc_nl_bc_link_set(net, attrs);
1960
1961         node = tipc_link_find_owner(net, name, &bearer_id);
1962         if (!node)
1963                 return -EINVAL;
1964
1965         tipc_node_lock(node);
1966
1967         link = node->links[bearer_id].link;
1968         if (!link) {
1969                 res = -EINVAL;
1970                 goto out;
1971         }
1972
1973         if (attrs[TIPC_NLA_LINK_PROP]) {
1974                 struct nlattr *props[TIPC_NLA_PROP_MAX + 1];
1975
1976                 err = tipc_nl_parse_link_prop(attrs[TIPC_NLA_LINK_PROP],
1977                                               props);
1978                 if (err) {
1979                         res = err;
1980                         goto out;
1981                 }
1982
1983                 if (props[TIPC_NLA_PROP_TOL]) {
1984                         u32 tol;
1985
1986                         tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
1987                         link_set_supervision_props(link, tol);
1988                         tipc_link_proto_xmit(link, STATE_MSG, 0, 0, tol, 0);
1989                 }
1990                 if (props[TIPC_NLA_PROP_PRIO]) {
1991                         u32 prio;
1992
1993                         prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
1994                         link->priority = prio;
1995                         tipc_link_proto_xmit(link, STATE_MSG, 0, 0, 0, prio);
1996                 }
1997                 if (props[TIPC_NLA_PROP_WIN]) {
1998                         u32 win;
1999
2000                         win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
2001                         tipc_link_set_queue_limits(link, win);
2002                 }
2003         }
2004
2005 out:
2006         tipc_node_unlock(node);
2007
2008         return res;
2009 }
2010
2011 static int __tipc_nl_add_stats(struct sk_buff *skb, struct tipc_stats *s)
2012 {
2013         int i;
2014         struct nlattr *stats;
2015
2016         struct nla_map {
2017                 u32 key;
2018                 u32 val;
2019         };
2020
2021         struct nla_map map[] = {
2022                 {TIPC_NLA_STATS_RX_INFO, s->recv_info},
2023                 {TIPC_NLA_STATS_RX_FRAGMENTS, s->recv_fragments},
2024                 {TIPC_NLA_STATS_RX_FRAGMENTED, s->recv_fragmented},
2025                 {TIPC_NLA_STATS_RX_BUNDLES, s->recv_bundles},
2026                 {TIPC_NLA_STATS_RX_BUNDLED, s->recv_bundled},
2027                 {TIPC_NLA_STATS_TX_INFO, s->sent_info},
2028                 {TIPC_NLA_STATS_TX_FRAGMENTS, s->sent_fragments},
2029                 {TIPC_NLA_STATS_TX_FRAGMENTED, s->sent_fragmented},
2030                 {TIPC_NLA_STATS_TX_BUNDLES, s->sent_bundles},
2031                 {TIPC_NLA_STATS_TX_BUNDLED, s->sent_bundled},
2032                 {TIPC_NLA_STATS_MSG_PROF_TOT, (s->msg_length_counts) ?
2033                         s->msg_length_counts : 1},
2034                 {TIPC_NLA_STATS_MSG_LEN_CNT, s->msg_length_counts},
2035                 {TIPC_NLA_STATS_MSG_LEN_TOT, s->msg_lengths_total},
2036                 {TIPC_NLA_STATS_MSG_LEN_P0, s->msg_length_profile[0]},
2037                 {TIPC_NLA_STATS_MSG_LEN_P1, s->msg_length_profile[1]},
2038                 {TIPC_NLA_STATS_MSG_LEN_P2, s->msg_length_profile[2]},
2039                 {TIPC_NLA_STATS_MSG_LEN_P3, s->msg_length_profile[3]},
2040                 {TIPC_NLA_STATS_MSG_LEN_P4, s->msg_length_profile[4]},
2041                 {TIPC_NLA_STATS_MSG_LEN_P5, s->msg_length_profile[5]},
2042                 {TIPC_NLA_STATS_MSG_LEN_P6, s->msg_length_profile[6]},
2043                 {TIPC_NLA_STATS_RX_STATES, s->recv_states},
2044                 {TIPC_NLA_STATS_RX_PROBES, s->recv_probes},
2045                 {TIPC_NLA_STATS_RX_NACKS, s->recv_nacks},
2046                 {TIPC_NLA_STATS_RX_DEFERRED, s->deferred_recv},
2047                 {TIPC_NLA_STATS_TX_STATES, s->sent_states},
2048                 {TIPC_NLA_STATS_TX_PROBES, s->sent_probes},
2049                 {TIPC_NLA_STATS_TX_NACKS, s->sent_nacks},
2050                 {TIPC_NLA_STATS_TX_ACKS, s->sent_acks},
2051                 {TIPC_NLA_STATS_RETRANSMITTED, s->retransmitted},
2052                 {TIPC_NLA_STATS_DUPLICATES, s->duplicates},
2053                 {TIPC_NLA_STATS_LINK_CONGS, s->link_congs},
2054                 {TIPC_NLA_STATS_MAX_QUEUE, s->max_queue_sz},
2055                 {TIPC_NLA_STATS_AVG_QUEUE, s->queue_sz_counts ?
2056                         (s->accu_queue_sz / s->queue_sz_counts) : 0}
2057         };
2058
2059         stats = nla_nest_start(skb, TIPC_NLA_LINK_STATS);
2060         if (!stats)
2061                 return -EMSGSIZE;
2062
2063         for (i = 0; i <  ARRAY_SIZE(map); i++)
2064                 if (nla_put_u32(skb, map[i].key, map[i].val))
2065                         goto msg_full;
2066
2067         nla_nest_end(skb, stats);
2068
2069         return 0;
2070 msg_full:
2071         nla_nest_cancel(skb, stats);
2072
2073         return -EMSGSIZE;
2074 }
2075
2076 /* Caller should hold appropriate locks to protect the link */
2077 static int __tipc_nl_add_link(struct net *net, struct tipc_nl_msg *msg,
2078                               struct tipc_link *link, int nlflags)
2079 {
2080         int err;
2081         void *hdr;
2082         struct nlattr *attrs;
2083         struct nlattr *prop;
2084         struct tipc_net *tn = net_generic(net, tipc_net_id);
2085
2086         hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
2087                           nlflags, TIPC_NL_LINK_GET);
2088         if (!hdr)
2089                 return -EMSGSIZE;
2090
2091         attrs = nla_nest_start(msg->skb, TIPC_NLA_LINK);
2092         if (!attrs)
2093                 goto msg_full;
2094
2095         if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, link->name))
2096                 goto attr_msg_full;
2097         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_DEST,
2098                         tipc_cluster_mask(tn->own_addr)))
2099                 goto attr_msg_full;
2100         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_MTU, link->mtu))
2101                 goto attr_msg_full;
2102         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, link->rcv_nxt))
2103                 goto attr_msg_full;
2104         if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, link->snd_nxt))
2105                 goto attr_msg_full;
2106
2107         if (tipc_link_is_up(link))
2108                 if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
2109                         goto attr_msg_full;
2110         if (tipc_link_is_active(link))
2111                 if (nla_put_flag(msg->skb, TIPC_NLA_LINK_ACTIVE))
2112                         goto attr_msg_full;
2113
2114         prop = nla_nest_start(msg->skb, TIPC_NLA_LINK_PROP);
2115         if (!prop)
2116                 goto attr_msg_full;
2117         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
2118                 goto prop_msg_full;
2119         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_TOL, link->tolerance))
2120                 goto prop_msg_full;
2121         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN,
2122                         link->window))
2123                 goto prop_msg_full;
2124         if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
2125                 goto prop_msg_full;
2126         nla_nest_end(msg->skb, prop);
2127
2128         err = __tipc_nl_add_stats(msg->skb, &link->stats);
2129         if (err)
2130                 goto attr_msg_full;
2131
2132         nla_nest_end(msg->skb, attrs);
2133         genlmsg_end(msg->skb, hdr);
2134
2135         return 0;
2136
2137 prop_msg_full:
2138         nla_nest_cancel(msg->skb, prop);
2139 attr_msg_full:
2140         nla_nest_cancel(msg->skb, attrs);
2141 msg_full:
2142         genlmsg_cancel(msg->skb, hdr);
2143
2144         return -EMSGSIZE;
2145 }
2146
2147 /* Caller should hold node lock  */
2148 static int __tipc_nl_add_node_links(struct net *net, struct tipc_nl_msg *msg,
2149                                     struct tipc_node *node, u32 *prev_link)
2150 {
2151         u32 i;
2152         int err;
2153
2154         for (i = *prev_link; i < MAX_BEARERS; i++) {
2155                 *prev_link = i;
2156
2157                 if (!node->links[i].link)
2158                         continue;
2159
2160                 err = __tipc_nl_add_link(net, msg,
2161                                          node->links[i].link, NLM_F_MULTI);
2162                 if (err)
2163                         return err;
2164         }
2165         *prev_link = 0;
2166
2167         return 0;
2168 }
2169
2170 int tipc_nl_link_dump(struct sk_buff *skb, struct netlink_callback *cb)
2171 {
2172         struct net *net = sock_net(skb->sk);
2173         struct tipc_net *tn = net_generic(net, tipc_net_id);
2174         struct tipc_node *node;
2175         struct tipc_nl_msg msg;
2176         u32 prev_node = cb->args[0];
2177         u32 prev_link = cb->args[1];
2178         int done = cb->args[2];
2179         int err;
2180
2181         if (done)
2182                 return 0;
2183
2184         msg.skb = skb;
2185         msg.portid = NETLINK_CB(cb->skb).portid;
2186         msg.seq = cb->nlh->nlmsg_seq;
2187
2188         rcu_read_lock();
2189         if (prev_node) {
2190                 node = tipc_node_find(net, prev_node);
2191                 if (!node) {
2192                         /* We never set seq or call nl_dump_check_consistent()
2193                          * this means that setting prev_seq here will cause the
2194                          * consistence check to fail in the netlink callback
2195                          * handler. Resulting in the last NLMSG_DONE message
2196                          * having the NLM_F_DUMP_INTR flag set.
2197                          */
2198                         cb->prev_seq = 1;
2199                         goto out;
2200                 }
2201                 tipc_node_put(node);
2202
2203                 list_for_each_entry_continue_rcu(node, &tn->node_list,
2204                                                  list) {
2205                         tipc_node_lock(node);
2206                         err = __tipc_nl_add_node_links(net, &msg, node,
2207                                                        &prev_link);
2208                         tipc_node_unlock(node);
2209                         if (err)
2210                                 goto out;
2211
2212                         prev_node = node->addr;
2213                 }
2214         } else {
2215                 err = tipc_nl_add_bc_link(net, &msg);
2216                 if (err)
2217                         goto out;
2218
2219                 list_for_each_entry_rcu(node, &tn->node_list, list) {
2220                         tipc_node_lock(node);
2221                         err = __tipc_nl_add_node_links(net, &msg, node,
2222                                                        &prev_link);
2223                         tipc_node_unlock(node);
2224                         if (err)
2225                                 goto out;
2226
2227                         prev_node = node->addr;
2228                 }
2229         }
2230         done = 1;
2231 out:
2232         rcu_read_unlock();
2233
2234         cb->args[0] = prev_node;
2235         cb->args[1] = prev_link;
2236         cb->args[2] = done;
2237
2238         return skb->len;
2239 }
2240
2241 int tipc_nl_link_get(struct sk_buff *skb, struct genl_info *info)
2242 {
2243         struct net *net = genl_info_net(info);
2244         struct tipc_nl_msg msg;
2245         char *name;
2246         int err;
2247
2248         msg.portid = info->snd_portid;
2249         msg.seq = info->snd_seq;
2250
2251         if (!info->attrs[TIPC_NLA_LINK_NAME])
2252                 return -EINVAL;
2253         name = nla_data(info->attrs[TIPC_NLA_LINK_NAME]);
2254
2255         msg.skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
2256         if (!msg.skb)
2257                 return -ENOMEM;
2258
2259         if (strcmp(name, tipc_bclink_name) == 0) {
2260                 err = tipc_nl_add_bc_link(net, &msg);
2261                 if (err) {
2262                         nlmsg_free(msg.skb);
2263                         return err;
2264                 }
2265         } else {
2266                 int bearer_id;
2267                 struct tipc_node *node;
2268                 struct tipc_link *link;
2269
2270                 node = tipc_link_find_owner(net, name, &bearer_id);
2271                 if (!node)
2272                         return -EINVAL;
2273
2274                 tipc_node_lock(node);
2275                 link = node->links[bearer_id].link;
2276                 if (!link) {
2277                         tipc_node_unlock(node);
2278                         nlmsg_free(msg.skb);
2279                         return -EINVAL;
2280                 }
2281
2282                 err = __tipc_nl_add_link(net, &msg, link, 0);
2283                 tipc_node_unlock(node);
2284                 if (err) {
2285                         nlmsg_free(msg.skb);
2286                         return err;
2287                 }
2288         }
2289
2290         return genlmsg_reply(msg.skb, info);
2291 }
2292
2293 int tipc_nl_link_reset_stats(struct sk_buff *skb, struct genl_info *info)
2294 {
2295         int err;
2296         char *link_name;
2297         unsigned int bearer_id;
2298         struct tipc_link *link;
2299         struct tipc_node *node;
2300         struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
2301         struct net *net = sock_net(skb->sk);
2302
2303         if (!info->attrs[TIPC_NLA_LINK])
2304                 return -EINVAL;
2305
2306         err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
2307                                info->attrs[TIPC_NLA_LINK],
2308                                tipc_nl_link_policy);
2309         if (err)
2310                 return err;
2311
2312         if (!attrs[TIPC_NLA_LINK_NAME])
2313                 return -EINVAL;
2314
2315         link_name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
2316
2317         if (strcmp(link_name, tipc_bclink_name) == 0) {
2318                 err = tipc_bclink_reset_stats(net);
2319                 if (err)
2320                         return err;
2321                 return 0;
2322         }
2323
2324         node = tipc_link_find_owner(net, link_name, &bearer_id);
2325         if (!node)
2326                 return -EINVAL;
2327
2328         tipc_node_lock(node);
2329
2330         link = node->links[bearer_id].link;
2331         if (!link) {
2332                 tipc_node_unlock(node);
2333                 return -EINVAL;
2334         }
2335
2336         link_reset_statistics(link);
2337
2338         tipc_node_unlock(node);
2339
2340         return 0;
2341 }