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