net/tipc/link.c

   1 /*
   2  * net/tipc/link.c: TIPC link code
   3  *
   4  * Copyright (c) 1996-2007, 2012-2014, 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 "link.h"
  39 #include "port.h"
  40 #include "socket.h"
  41 #include "name_distr.h"
  42 #include "discover.h"
  43 #include "config.h"
  44
  45 #include <linux/pkt_sched.h>
  46
  47 /*
  48  * Error message prefixes
  49  */
  50 static const char *link_co_err = "Link changeover error, ";
  51 static const char *link_rst_msg = "Resetting link ";
  52 static const char *link_unk_evt = "Unknown link event ";
  53
  54 /*
  55  * Out-of-range value for link session numbers
  56  */
  57 #define INVALID_SESSION 0x10000
  58
  59 /*
  60  * Link state events:
  61  */
  62 #define  STARTING_EVT    856384768      /* link processing trigger */
  63 #define  TRAFFIC_MSG_EVT 560815u        /* rx'd ??? */
  64 #define  TIMEOUT_EVT     560817u        /* link timer expired */
  65
  66 /*
  67  * The following two 'message types' is really just implementation
  68  * data conveniently stored in the message header.
  69  * They must not be considered part of the protocol
  70  */
  71 #define OPEN_MSG   0
  72 #define CLOSED_MSG 1
  73
  74 /*
  75  * State value stored in 'exp_msg_count'
  76  */
  77 #define START_CHANGEOVER 100000u
  78
  79 static void link_handle_out_of_seq_msg(struct tipc_link *l_ptr,
  80                                        struct sk_buff *buf);
  81 static void tipc_link_proto_rcv(struct tipc_link *l_ptr, struct sk_buff *buf);
  82 static int  tipc_link_tunnel_rcv(struct tipc_node *n_ptr,
  83                                  struct sk_buff **buf);
  84 static void link_set_supervision_props(struct tipc_link *l_ptr, u32 tolerance);
  85 static void link_state_event(struct tipc_link *l_ptr, u32 event);
  86 static void link_reset_statistics(struct tipc_link *l_ptr);
  87 static void link_print(struct tipc_link *l_ptr, const char *str);
  88 static int tipc_link_frag_xmit(struct tipc_link *l_ptr, struct sk_buff *buf);
  89 static void tipc_link_sync_xmit(struct tipc_link *l);
  90 static void tipc_link_sync_rcv(struct tipc_node *n, struct sk_buff *buf);
  91 static int tipc_link_input(struct tipc_link *l, struct sk_buff *buf);
  92 static int tipc_link_prepare_input(struct tipc_link *l, struct sk_buff **buf);
  93
  94 /*
  95  *  Simple link routines
  96  */
  97 static unsigned int align(unsigned int i)
  98 {
  99         return (i + 3) & ~3u;
 100 }
 101
 102 static void link_init_max_pkt(struct tipc_link *l_ptr)
 103 {
 104         struct tipc_bearer *b_ptr;
 105         u32 max_pkt;
 106
 107         rcu_read_lock();
 108         b_ptr = rcu_dereference_rtnl(bearer_list[l_ptr->bearer_id]);
 109         if (!b_ptr) {
 110                 rcu_read_unlock();
 111                 return;
 112         }
 113         max_pkt = (b_ptr->mtu & ~3);
 114         rcu_read_unlock();
 115
 116         if (max_pkt > MAX_MSG_SIZE)
 117                 max_pkt = MAX_MSG_SIZE;
 118
 119         l_ptr->max_pkt_target = max_pkt;
 120         if (l_ptr->max_pkt_target < MAX_PKT_DEFAULT)
 121                 l_ptr->max_pkt = l_ptr->max_pkt_target;
 122         else
 123                 l_ptr->max_pkt = MAX_PKT_DEFAULT;
 124
 125         l_ptr->max_pkt_probes = 0;
 126 }
 127
 128 static u32 link_next_sent(struct tipc_link *l_ptr)
 129 {
 130         if (l_ptr->next_out)
 131                 return buf_seqno(l_ptr->next_out);
 132         return mod(l_ptr->next_out_no);
 133 }
 134
 135 static u32 link_last_sent(struct tipc_link *l_ptr)
 136 {
 137         return mod(link_next_sent(l_ptr) - 1);
 138 }
 139
 140 /*
 141  *  Simple non-static link routines (i.e. referenced outside this file)
 142  */
 143 int tipc_link_is_up(struct tipc_link *l_ptr)
 144 {
 145         if (!l_ptr)
 146                 return 0;
 147         return link_working_working(l_ptr) || link_working_unknown(l_ptr);
 148 }
 149
 150 int tipc_link_is_active(struct tipc_link *l_ptr)
 151 {
 152         return  (l_ptr->owner->active_links[0] == l_ptr) ||
 153                 (l_ptr->owner->active_links[1] == l_ptr);
 154 }
 155
 156 /**
 157  * link_timeout - handle expiration of link timer
 158  * @l_ptr: pointer to link
 159  */
 160 static void link_timeout(struct tipc_link *l_ptr)
 161 {
 162         tipc_node_lock(l_ptr->owner);
 163
 164         /* update counters used in statistical profiling of send traffic */
 165         l_ptr->stats.accu_queue_sz += l_ptr->out_queue_size;
 166         l_ptr->stats.queue_sz_counts++;
 167
 168         if (l_ptr->first_out) {
 169                 struct tipc_msg *msg = buf_msg(l_ptr->first_out);
 170                 u32 length = msg_size(msg);
 171
 172                 if ((msg_user(msg) == MSG_FRAGMENTER) &&
 173                     (msg_type(msg) == FIRST_FRAGMENT)) {
 174                         length = msg_size(msg_get_wrapped(msg));
 175                 }
 176                 if (length) {
 177                         l_ptr->stats.msg_lengths_total += length;
 178                         l_ptr->stats.msg_length_counts++;
 179                         if (length <= 64)
 180                                 l_ptr->stats.msg_length_profile[0]++;
 181                         else if (length <= 256)
 182                                 l_ptr->stats.msg_length_profile[1]++;
 183                         else if (length <= 1024)
 184                                 l_ptr->stats.msg_length_profile[2]++;
 185                         else if (length <= 4096)
 186                                 l_ptr->stats.msg_length_profile[3]++;
 187                         else if (length <= 16384)
 188                                 l_ptr->stats.msg_length_profile[4]++;
 189                         else if (length <= 32768)
 190                                 l_ptr->stats.msg_length_profile[5]++;
 191                         else
 192                                 l_ptr->stats.msg_length_profile[6]++;
 193                 }
 194         }
 195
 196         /* do all other link processing performed on a periodic basis */
 197
 198         link_state_event(l_ptr, TIMEOUT_EVT);
 199
 200         if (l_ptr->next_out)
 201                 tipc_link_push_queue(l_ptr);
 202
 203         tipc_node_unlock(l_ptr->owner);
 204 }
 205
 206 static void link_set_timer(struct tipc_link *l_ptr, u32 time)
 207 {
 208         k_start_timer(&l_ptr->timer, time);
 209 }
 210
 211 /**
 212  * tipc_link_create - create a new link
 213  * @n_ptr: pointer to associated node
 214  * @b_ptr: pointer to associated bearer
 215  * @media_addr: media address to use when sending messages over link
 216  *
 217  * Returns pointer to link.
 218  */
 219 struct tipc_link *tipc_link_create(struct tipc_node *n_ptr,
 220                                    struct tipc_bearer *b_ptr,
 221                                    const struct tipc_media_addr *media_addr)
 222 {
 223         struct tipc_link *l_ptr;
 224         struct tipc_msg *msg;
 225         char *if_name;
 226         char addr_string[16];
 227         u32 peer = n_ptr->addr;
 228
 229         if (n_ptr->link_cnt >= 2) {
 230                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 231                 pr_err("Attempt to establish third link to %s\n", addr_string);
 232                 return NULL;
 233         }
 234
 235         if (n_ptr->links[b_ptr->identity]) {
 236                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 237                 pr_err("Attempt to establish second link on <%s> to %s\n",
 238                        b_ptr->name, addr_string);
 239                 return NULL;
 240         }
 241
 242         l_ptr = kzalloc(sizeof(*l_ptr), GFP_ATOMIC);
 243         if (!l_ptr) {
 244                 pr_warn("Link creation failed, no memory\n");
 245                 return NULL;
 246         }
 247
 248         l_ptr->addr = peer;
 249         if_name = strchr(b_ptr->name, ':') + 1;
 250         sprintf(l_ptr->name, "%u.%u.%u:%s-%u.%u.%u:unknown",
 251                 tipc_zone(tipc_own_addr), tipc_cluster(tipc_own_addr),
 252                 tipc_node(tipc_own_addr),
 253                 if_name,
 254                 tipc_zone(peer), tipc_cluster(peer), tipc_node(peer));
 255                 /* note: peer i/f name is updated by reset/activate message */
 256         memcpy(&l_ptr->media_addr, media_addr, sizeof(*media_addr));
 257         l_ptr->owner = n_ptr;
 258         l_ptr->checkpoint = 1;
 259         l_ptr->peer_session = INVALID_SESSION;
 260         l_ptr->bearer_id = b_ptr->identity;
 261         link_set_supervision_props(l_ptr, b_ptr->tolerance);
 262         l_ptr->state = RESET_UNKNOWN;
 263
 264         l_ptr->pmsg = (struct tipc_msg *)&l_ptr->proto_msg;
 265         msg = l_ptr->pmsg;
 266         tipc_msg_init(msg, LINK_PROTOCOL, RESET_MSG, INT_H_SIZE, l_ptr->addr);
 267         msg_set_size(msg, sizeof(l_ptr->proto_msg));
 268         msg_set_session(msg, (tipc_random & 0xffff));
 269         msg_set_bearer_id(msg, b_ptr->identity);
 270         strcpy((char *)msg_data(msg), if_name);
 271
 272         l_ptr->priority = b_ptr->priority;
 273         tipc_link_set_queue_limits(l_ptr, b_ptr->window);
 274
 275         l_ptr->net_plane = b_ptr->net_plane;
 276         link_init_max_pkt(l_ptr);
 277
 278         l_ptr->next_out_no = 1;
 279         INIT_LIST_HEAD(&l_ptr->waiting_ports);
 280
 281         link_reset_statistics(l_ptr);
 282
 283         tipc_node_attach_link(n_ptr, l_ptr);
 284
 285         k_init_timer(&l_ptr->timer, (Handler)link_timeout,
 286                      (unsigned long)l_ptr);
 287
 288         link_state_event(l_ptr, STARTING_EVT);
 289
 290         return l_ptr;
 291 }
 292
 293 void tipc_link_delete_list(unsigned int bearer_id, bool shutting_down)
 294 {
 295         struct tipc_link *l_ptr;
 296         struct tipc_node *n_ptr;
 297
 298         rcu_read_lock();
 299         list_for_each_entry_rcu(n_ptr, &tipc_node_list, list) {
 300                 tipc_node_lock(n_ptr);
 301                 l_ptr = n_ptr->links[bearer_id];
 302                 if (l_ptr) {
 303                         tipc_link_reset(l_ptr);
 304                         if (shutting_down || !tipc_node_is_up(n_ptr)) {
 305                                 tipc_node_detach_link(l_ptr->owner, l_ptr);
 306                                 tipc_link_reset_fragments(l_ptr);
 307                                 tipc_node_unlock(n_ptr);
 308
 309                                 /* Nobody else can access this link now: */
 310                                 del_timer_sync(&l_ptr->timer);
 311                                 kfree(l_ptr);
 312                         } else {
 313                                 /* Detach/delete when failover is finished: */
 314                                 l_ptr->flags |= LINK_STOPPED;
 315                                 tipc_node_unlock(n_ptr);
 316                                 del_timer_sync(&l_ptr->timer);
 317                         }
 318                         continue;
 319                 }
 320                 tipc_node_unlock(n_ptr);
 321         }
 322         rcu_read_unlock();
 323 }
 324
 325 /**
 326  * link_schedule_port - schedule port for deferred sending
 327  * @l_ptr: pointer to link
 328  * @origport: reference to sending port
 329  * @sz: amount of data to be sent
 330  *
 331  * Schedules port for renewed sending of messages after link congestion
 332  * has abated.
 333  */
 334 static int link_schedule_port(struct tipc_link *l_ptr, u32 origport, u32 sz)
 335 {
 336         struct tipc_port *p_ptr;
 337         struct tipc_sock *tsk;
 338
 339         spin_lock_bh(&tipc_port_list_lock);
 340         p_ptr = tipc_port_lock(origport);
 341         if (p_ptr) {
 342                 if (!list_empty(&p_ptr->wait_list))
 343                         goto exit;
 344                 tsk = tipc_port_to_sock(p_ptr);
 345                 tsk->link_cong = 1;
 346                 p_ptr->waiting_pkts = 1 + ((sz - 1) / l_ptr->max_pkt);
 347                 list_add_tail(&p_ptr->wait_list, &l_ptr->waiting_ports);
 348                 l_ptr->stats.link_congs++;
 349 exit:
 350                 tipc_port_unlock(p_ptr);
 351         }
 352         spin_unlock_bh(&tipc_port_list_lock);
 353         return -ELINKCONG;
 354 }
 355
 356 void tipc_link_wakeup_ports(struct tipc_link *l_ptr, int all)
 357 {
 358         struct tipc_port *p_ptr;
 359         struct tipc_sock *tsk;
 360         struct tipc_port *temp_p_ptr;
 361         int win = l_ptr->queue_limit[0] - l_ptr->out_queue_size;
 362
 363         if (all)
 364                 win = 100000;
 365         if (win <= 0)
 366                 return;
 367         if (!spin_trylock_bh(&tipc_port_list_lock))
 368                 return;
 369         if (link_congested(l_ptr))
 370                 goto exit;
 371         list_for_each_entry_safe(p_ptr, temp_p_ptr, &l_ptr->waiting_ports,
 372                                  wait_list) {
 373                 if (win <= 0)
 374                         break;
 375                 tsk = tipc_port_to_sock(p_ptr);
 376                 list_del_init(&p_ptr->wait_list);
 377                 spin_lock_bh(p_ptr->lock);
 378                 tsk->link_cong = 0;
 379                 tipc_sock_wakeup(tsk);
 380                 win -= p_ptr->waiting_pkts;
 381                 spin_unlock_bh(p_ptr->lock);
 382         }
 383
 384 exit:
 385         spin_unlock_bh(&tipc_port_list_lock);
 386 }
 387
 388 /**
 389  * link_release_outqueue - purge link's outbound message queue
 390  * @l_ptr: pointer to link
 391  */
 392 static void link_release_outqueue(struct tipc_link *l_ptr)
 393 {
 394         kfree_skb_list(l_ptr->first_out);
 395         l_ptr->first_out = NULL;
 396         l_ptr->out_queue_size = 0;
 397 }
 398
 399 /**
 400  * tipc_link_reset_fragments - purge link's inbound message fragments queue
 401  * @l_ptr: pointer to link
 402  */
 403 void tipc_link_reset_fragments(struct tipc_link *l_ptr)
 404 {
 405         kfree_skb(l_ptr->reasm_buf);
 406         l_ptr->reasm_buf = NULL;
 407 }
 408
 409 /**
 410  * tipc_link_purge_queues - purge all pkt queues associated with link
 411  * @l_ptr: pointer to link
 412  */
 413 void tipc_link_purge_queues(struct tipc_link *l_ptr)
 414 {
 415         kfree_skb_list(l_ptr->oldest_deferred_in);
 416         kfree_skb_list(l_ptr->first_out);
 417         tipc_link_reset_fragments(l_ptr);
 418         kfree_skb(l_ptr->proto_msg_queue);
 419         l_ptr->proto_msg_queue = NULL;
 420 }
 421
 422 void tipc_link_reset(struct tipc_link *l_ptr)
 423 {
 424         u32 prev_state = l_ptr->state;
 425         u32 checkpoint = l_ptr->next_in_no;
 426         int was_active_link = tipc_link_is_active(l_ptr);
 427
 428         msg_set_session(l_ptr->pmsg, ((msg_session(l_ptr->pmsg) + 1) & 0xffff));
 429
 430         /* Link is down, accept any session */
 431         l_ptr->peer_session = INVALID_SESSION;
 432
 433         /* Prepare for max packet size negotiation */
 434         link_init_max_pkt(l_ptr);
 435
 436         l_ptr->state = RESET_UNKNOWN;
 437
 438         if ((prev_state == RESET_UNKNOWN) || (prev_state == RESET_RESET))
 439                 return;
 440
 441         tipc_node_link_down(l_ptr->owner, l_ptr);
 442         tipc_bearer_remove_dest(l_ptr->bearer_id, l_ptr->addr);
 443
 444         if (was_active_link && tipc_node_active_links(l_ptr->owner)) {
 445                 l_ptr->reset_checkpoint = checkpoint;
 446                 l_ptr->exp_msg_count = START_CHANGEOVER;
 447         }
 448
 449         /* Clean up all queues: */
 450         link_release_outqueue(l_ptr);
 451         kfree_skb(l_ptr->proto_msg_queue);
 452         l_ptr->proto_msg_queue = NULL;
 453         kfree_skb_list(l_ptr->oldest_deferred_in);
 454         if (!list_empty(&l_ptr->waiting_ports))
 455                 tipc_link_wakeup_ports(l_ptr, 1);
 456
 457         l_ptr->retransm_queue_head = 0;
 458         l_ptr->retransm_queue_size = 0;
 459         l_ptr->last_out = NULL;
 460         l_ptr->first_out = NULL;
 461         l_ptr->next_out = NULL;
 462         l_ptr->unacked_window = 0;
 463         l_ptr->checkpoint = 1;
 464         l_ptr->next_out_no = 1;
 465         l_ptr->deferred_inqueue_sz = 0;
 466         l_ptr->oldest_deferred_in = NULL;
 467         l_ptr->newest_deferred_in = NULL;
 468         l_ptr->fsm_msg_cnt = 0;
 469         l_ptr->stale_count = 0;
 470         link_reset_statistics(l_ptr);
 471 }
 472
 473 void tipc_link_reset_list(unsigned int bearer_id)
 474 {
 475         struct tipc_link *l_ptr;
 476         struct tipc_node *n_ptr;
 477
 478         rcu_read_lock();
 479         list_for_each_entry_rcu(n_ptr, &tipc_node_list, list) {
 480                 tipc_node_lock(n_ptr);
 481                 l_ptr = n_ptr->links[bearer_id];
 482                 if (l_ptr)
 483                         tipc_link_reset(l_ptr);
 484                 tipc_node_unlock(n_ptr);
 485         }
 486         rcu_read_unlock();
 487 }
 488
 489 static void link_activate(struct tipc_link *l_ptr)
 490 {
 491         l_ptr->next_in_no = l_ptr->stats.recv_info = 1;
 492         tipc_node_link_up(l_ptr->owner, l_ptr);
 493         tipc_bearer_add_dest(l_ptr->bearer_id, l_ptr->addr);
 494 }
 495
 496 /**
 497  * link_state_event - link finite state machine
 498  * @l_ptr: pointer to link
 499  * @event: state machine event to process
 500  */
 501 static void link_state_event(struct tipc_link *l_ptr, unsigned int event)
 502 {
 503         struct tipc_link *other;
 504         u32 cont_intv = l_ptr->continuity_interval;
 505
 506         if (l_ptr->flags & LINK_STOPPED)
 507                 return;
 508
 509         if (!(l_ptr->flags & LINK_STARTED) && (event != STARTING_EVT))
 510                 return;         /* Not yet. */
 511
 512         /* Check whether changeover is going on */
 513         if (l_ptr->exp_msg_count) {
 514                 if (event == TIMEOUT_EVT)
 515                         link_set_timer(l_ptr, cont_intv);
 516                 return;
 517         }
 518
 519         switch (l_ptr->state) {
 520         case WORKING_WORKING:
 521                 switch (event) {
 522                 case TRAFFIC_MSG_EVT:
 523                 case ACTIVATE_MSG:
 524                         break;
 525                 case TIMEOUT_EVT:
 526                         if (l_ptr->next_in_no != l_ptr->checkpoint) {
 527                                 l_ptr->checkpoint = l_ptr->next_in_no;
 528                                 if (tipc_bclink_acks_missing(l_ptr->owner)) {
 529                                         tipc_link_proto_xmit(l_ptr, STATE_MSG,
 530                                                              0, 0, 0, 0, 0);
 531                                         l_ptr->fsm_msg_cnt++;
 532                                 } else if (l_ptr->max_pkt < l_ptr->max_pkt_target) {
 533                                         tipc_link_proto_xmit(l_ptr, STATE_MSG,
 534                                                              1, 0, 0, 0, 0);
 535                                         l_ptr->fsm_msg_cnt++;
 536                                 }
 537                                 link_set_timer(l_ptr, cont_intv);
 538                                 break;
 539                         }
 540                         l_ptr->state = WORKING_UNKNOWN;
 541                         l_ptr->fsm_msg_cnt = 0;
 542                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
 543                         l_ptr->fsm_msg_cnt++;
 544                         link_set_timer(l_ptr, cont_intv / 4);
 545                         break;
 546                 case RESET_MSG:
 547                         pr_info("%s<%s>, requested by peer\n", link_rst_msg,
 548                                 l_ptr->name);
 549                         tipc_link_reset(l_ptr);
 550                         l_ptr->state = RESET_RESET;
 551                         l_ptr->fsm_msg_cnt = 0;
 552                         tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
 553                                              0, 0, 0, 0, 0);
 554                         l_ptr->fsm_msg_cnt++;
 555                         link_set_timer(l_ptr, cont_intv);
 556                         break;
 557                 default:
 558                         pr_err("%s%u in WW state\n", link_unk_evt, event);
 559                 }
 560                 break;
 561         case WORKING_UNKNOWN:
 562                 switch (event) {
 563                 case TRAFFIC_MSG_EVT:
 564                 case ACTIVATE_MSG:
 565                         l_ptr->state = WORKING_WORKING;
 566                         l_ptr->fsm_msg_cnt = 0;
 567                         link_set_timer(l_ptr, cont_intv);
 568                         break;
 569                 case RESET_MSG:
 570                         pr_info("%s<%s>, requested by peer while probing\n",
 571                                 link_rst_msg, l_ptr->name);
 572                         tipc_link_reset(l_ptr);
 573                         l_ptr->state = RESET_RESET;
 574                         l_ptr->fsm_msg_cnt = 0;
 575                         tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
 576                                              0, 0, 0, 0, 0);
 577                         l_ptr->fsm_msg_cnt++;
 578                         link_set_timer(l_ptr, cont_intv);
 579                         break;
 580                 case TIMEOUT_EVT:
 581                         if (l_ptr->next_in_no != l_ptr->checkpoint) {
 582                                 l_ptr->state = WORKING_WORKING;
 583                                 l_ptr->fsm_msg_cnt = 0;
 584                                 l_ptr->checkpoint = l_ptr->next_in_no;
 585                                 if (tipc_bclink_acks_missing(l_ptr->owner)) {
 586                                         tipc_link_proto_xmit(l_ptr, STATE_MSG,
 587                                                              0, 0, 0, 0, 0);
 588                                         l_ptr->fsm_msg_cnt++;
 589                                 }
 590                                 link_set_timer(l_ptr, cont_intv);
 591                         } else if (l_ptr->fsm_msg_cnt < l_ptr->abort_limit) {
 592                                 tipc_link_proto_xmit(l_ptr, STATE_MSG,
 593                                                      1, 0, 0, 0, 0);
 594                                 l_ptr->fsm_msg_cnt++;
 595                                 link_set_timer(l_ptr, cont_intv / 4);
 596                         } else {        /* Link has failed */
 597                                 pr_warn("%s<%s>, peer not responding\n",
 598                                         link_rst_msg, l_ptr->name);
 599                                 tipc_link_reset(l_ptr);
 600                                 l_ptr->state = RESET_UNKNOWN;
 601                                 l_ptr->fsm_msg_cnt = 0;
 602                                 tipc_link_proto_xmit(l_ptr, RESET_MSG,
 603                                                      0, 0, 0, 0, 0);
 604                                 l_ptr->fsm_msg_cnt++;
 605                                 link_set_timer(l_ptr, cont_intv);
 606                         }
 607                         break;
 608                 default:
 609                         pr_err("%s%u in WU state\n", link_unk_evt, event);
 610                 }
 611                 break;
 612         case RESET_UNKNOWN:
 613                 switch (event) {
 614                 case TRAFFIC_MSG_EVT:
 615                         break;
 616                 case ACTIVATE_MSG:
 617                         other = l_ptr->owner->active_links[0];
 618                         if (other && link_working_unknown(other))
 619                                 break;
 620                         l_ptr->state = WORKING_WORKING;
 621                         l_ptr->fsm_msg_cnt = 0;
 622                         link_activate(l_ptr);
 623                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
 624                         l_ptr->fsm_msg_cnt++;
 625                         if (l_ptr->owner->working_links == 1)
 626                                 tipc_link_sync_xmit(l_ptr);
 627                         link_set_timer(l_ptr, cont_intv);
 628                         break;
 629                 case RESET_MSG:
 630                         l_ptr->state = RESET_RESET;
 631                         l_ptr->fsm_msg_cnt = 0;
 632                         tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
 633                                              1, 0, 0, 0, 0);
 634                         l_ptr->fsm_msg_cnt++;
 635                         link_set_timer(l_ptr, cont_intv);
 636                         break;
 637                 case STARTING_EVT:
 638                         l_ptr->flags |= LINK_STARTED;
 639                         /* fall through */
 640                 case TIMEOUT_EVT:
 641                         tipc_link_proto_xmit(l_ptr, RESET_MSG, 0, 0, 0, 0, 0);
 642                         l_ptr->fsm_msg_cnt++;
 643                         link_set_timer(l_ptr, cont_intv);
 644                         break;
 645                 default:
 646                         pr_err("%s%u in RU state\n", link_unk_evt, event);
 647                 }
 648                 break;
 649         case RESET_RESET:
 650                 switch (event) {
 651                 case TRAFFIC_MSG_EVT:
 652                 case ACTIVATE_MSG:
 653                         other = l_ptr->owner->active_links[0];
 654                         if (other && link_working_unknown(other))
 655                                 break;
 656                         l_ptr->state = WORKING_WORKING;
 657                         l_ptr->fsm_msg_cnt = 0;
 658                         link_activate(l_ptr);
 659                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
 660                         l_ptr->fsm_msg_cnt++;
 661                         if (l_ptr->owner->working_links == 1)
 662                                 tipc_link_sync_xmit(l_ptr);
 663                         link_set_timer(l_ptr, cont_intv);
 664                         break;
 665                 case RESET_MSG:
 666                         break;
 667                 case TIMEOUT_EVT:
 668                         tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
 669                                              0, 0, 0, 0, 0);
 670                         l_ptr->fsm_msg_cnt++;
 671                         link_set_timer(l_ptr, cont_intv);
 672                         break;
 673                 default:
 674                         pr_err("%s%u in RR state\n", link_unk_evt, event);
 675                 }
 676                 break;
 677         default:
 678                 pr_err("Unknown link state %u/%u\n", l_ptr->state, event);
 679         }
 680 }
 681
 682 /*
 683  * link_bundle_buf(): Append contents of a buffer to
 684  * the tail of an existing one.
 685  */
 686 static int link_bundle_buf(struct tipc_link *l_ptr, struct sk_buff *bundler,
 687                            struct sk_buff *buf)
 688 {
 689         struct tipc_msg *bundler_msg = buf_msg(bundler);
 690         struct tipc_msg *msg = buf_msg(buf);
 691         u32 size = msg_size(msg);
 692         u32 bundle_size = msg_size(bundler_msg);
 693         u32 to_pos = align(bundle_size);
 694         u32 pad = to_pos - bundle_size;
 695
 696         if (msg_user(bundler_msg) != MSG_BUNDLER)
 697                 return 0;
 698         if (msg_type(bundler_msg) != OPEN_MSG)
 699                 return 0;
 700         if (skb_tailroom(bundler) < (pad + size))
 701                 return 0;
 702         if (l_ptr->max_pkt < (to_pos + size))
 703                 return 0;
 704
 705         skb_put(bundler, pad + size);
 706         skb_copy_to_linear_data_offset(bundler, to_pos, buf->data, size);
 707         msg_set_size(bundler_msg, to_pos + size);
 708         msg_set_msgcnt(bundler_msg, msg_msgcnt(bundler_msg) + 1);
 709         kfree_skb(buf);
 710         l_ptr->stats.sent_bundled++;
 711         return 1;
 712 }
 713
 714 static void link_add_to_outqueue(struct tipc_link *l_ptr,
 715                                  struct sk_buff *buf,
 716                                  struct tipc_msg *msg)
 717 {
 718         u32 ack = mod(l_ptr->next_in_no - 1);
 719         u32 seqno = mod(l_ptr->next_out_no++);
 720
 721         msg_set_word(msg, 2, ((ack << 16) | seqno));
 722         msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
 723         buf->next = NULL;
 724         if (l_ptr->first_out) {
 725                 l_ptr->last_out->next = buf;
 726                 l_ptr->last_out = buf;
 727         } else
 728                 l_ptr->first_out = l_ptr->last_out = buf;
 729
 730         l_ptr->out_queue_size++;
 731         if (l_ptr->out_queue_size > l_ptr->stats.max_queue_sz)
 732                 l_ptr->stats.max_queue_sz = l_ptr->out_queue_size;
 733 }
 734
 735 static void link_add_chain_to_outqueue(struct tipc_link *l_ptr,
 736                                        struct sk_buff *buf_chain,
 737                                        u32 long_msgno)
 738 {
 739         struct sk_buff *buf;
 740         struct tipc_msg *msg;
 741
 742         if (!l_ptr->next_out)
 743                 l_ptr->next_out = buf_chain;
 744         while (buf_chain) {
 745                 buf = buf_chain;
 746                 buf_chain = buf_chain->next;
 747
 748                 msg = buf_msg(buf);
 749                 msg_set_long_msgno(msg, long_msgno);
 750                 link_add_to_outqueue(l_ptr, buf, msg);
 751         }
 752 }
 753
 754 /*
 755  * tipc_link_xmit() is the 'full path' for messages, called from
 756  * inside TIPC when the 'fast path' in tipc_send_xmit
 757  * has failed, and from link_send()
 758  */
 759 int __tipc_link_xmit(struct tipc_link *l_ptr, struct sk_buff *buf)
 760 {
 761         struct tipc_msg *msg = buf_msg(buf);
 762         u32 size = msg_size(msg);
 763         u32 dsz = msg_data_sz(msg);
 764         u32 queue_size = l_ptr->out_queue_size;
 765         u32 imp = tipc_msg_tot_importance(msg);
 766         u32 queue_limit = l_ptr->queue_limit[imp];
 767         u32 max_packet = l_ptr->max_pkt;
 768
 769         /* Match msg importance against queue limits: */
 770         if (unlikely(queue_size >= queue_limit)) {
 771                 if (imp <= TIPC_CRITICAL_IMPORTANCE) {
 772                         link_schedule_port(l_ptr, msg_origport(msg), size);
 773                         kfree_skb(buf);
 774                         return -ELINKCONG;
 775                 }
 776                 kfree_skb(buf);
 777                 if (imp > CONN_MANAGER) {
 778                         pr_warn("%s<%s>, send queue full", link_rst_msg,
 779                                 l_ptr->name);
 780                         tipc_link_reset(l_ptr);
 781                 }
 782                 return dsz;
 783         }
 784
 785         /* Fragmentation needed ? */
 786         if (size > max_packet)
 787                 return tipc_link_frag_xmit(l_ptr, buf);
 788
 789         /* Packet can be queued or sent. */
 790         if (likely(!link_congested(l_ptr))) {
 791                 link_add_to_outqueue(l_ptr, buf, msg);
 792
 793                 tipc_bearer_send(l_ptr->bearer_id, buf, &l_ptr->media_addr);
 794                 l_ptr->unacked_window = 0;
 795                 return dsz;
 796         }
 797         /* Congestion: can message be bundled ? */
 798         if ((msg_user(msg) != CHANGEOVER_PROTOCOL) &&
 799             (msg_user(msg) != MSG_FRAGMENTER)) {
 800
 801                 /* Try adding message to an existing bundle */
 802                 if (l_ptr->next_out &&
 803                     link_bundle_buf(l_ptr, l_ptr->last_out, buf))
 804                         return dsz;
 805
 806                 /* Try creating a new bundle */
 807                 if (size <= max_packet * 2 / 3) {
 808                         struct sk_buff *bundler = tipc_buf_acquire(max_packet);
 809                         struct tipc_msg bundler_hdr;
 810
 811                         if (bundler) {
 812                                 tipc_msg_init(&bundler_hdr, MSG_BUNDLER, OPEN_MSG,
 813                                          INT_H_SIZE, l_ptr->addr);
 814                                 skb_copy_to_linear_data(bundler, &bundler_hdr,
 815                                                         INT_H_SIZE);
 816                                 skb_trim(bundler, INT_H_SIZE);
 817                                 link_bundle_buf(l_ptr, bundler, buf);
 818                                 buf = bundler;
 819                                 msg = buf_msg(buf);
 820                                 l_ptr->stats.sent_bundles++;
 821                         }
 822                 }
 823         }
 824         if (!l_ptr->next_out)
 825                 l_ptr->next_out = buf;
 826         link_add_to_outqueue(l_ptr, buf, msg);
 827         return dsz;
 828 }
 829
 830 /*
 831  * tipc_link_xmit(): same as __tipc_link_xmit(), but the link to use
 832  * has not been selected yet, and the the owner node is not locked
 833  * Called by TIPC internal users, e.g. the name distributor
 834  */
 835 int tipc_link_xmit(struct sk_buff *buf, u32 dest, u32 selector)
 836 {
 837         struct tipc_link *l_ptr;
 838         struct tipc_node *n_ptr;
 839         int res = -ELINKCONG;
 840
 841         n_ptr = tipc_node_find(dest);
 842         if (n_ptr) {
 843                 tipc_node_lock(n_ptr);
 844                 l_ptr = n_ptr->active_links[selector & 1];
 845                 if (l_ptr)
 846                         res = __tipc_link_xmit(l_ptr, buf);
 847                 else
 848                         kfree_skb(buf);
 849                 tipc_node_unlock(n_ptr);
 850         } else {
 851                 kfree_skb(buf);
 852         }
 853         return res;
 854 }
 855
 856 /* tipc_link_cong: determine return value and how to treat the
 857  * sent buffer during link congestion.
 858  * - For plain, errorless user data messages we keep the buffer and
 859  *   return -ELINKONG.
 860  * - For all other messages we discard the buffer and return -EHOSTUNREACH
 861  * - For TIPC internal messages we also reset the link
 862  */
 863 static int tipc_link_cong(struct tipc_link *link, struct sk_buff *buf)
 864 {
 865         struct tipc_msg *msg = buf_msg(buf);
 866         uint psz = msg_size(msg);
 867         uint imp = tipc_msg_tot_importance(msg);
 868         u32 oport = msg_tot_origport(msg);
 869
 870         if (likely(imp <= TIPC_CRITICAL_IMPORTANCE)) {
 871                 if (!msg_errcode(msg) && !msg_reroute_cnt(msg)) {
 872                         link_schedule_port(link, oport, psz);
 873                         return -ELINKCONG;
 874                 }
 875         } else {
 876                 pr_warn("%s<%s>, send queue full", link_rst_msg, link->name);
 877                 tipc_link_reset(link);
 878         }
 879         kfree_skb_list(buf);
 880         return -EHOSTUNREACH;
 881 }
 882
 883 /**
 884  * __tipc_link_xmit2(): same as tipc_link_xmit2, but destlink is known & locked
 885  * @link: link to use
 886  * @buf: chain of buffers containing message
 887  * Consumes the buffer chain, except when returning -ELINKCONG
 888  * Returns 0 if success, otherwise errno: -ELINKCONG, -EMSGSIZE (plain socket
 889  * user data messages) or -EHOSTUNREACH (all other messages/senders)
 890  * Only the socket functions tipc_send_stream() and tipc_send_packet() need
 891  * to act on the return value, since they may need to do more send attempts.
 892  */
 893 int __tipc_link_xmit2(struct tipc_link *link, struct sk_buff *buf)
 894 {
 895         struct tipc_msg *msg = buf_msg(buf);
 896         uint psz = msg_size(msg);
 897         uint qsz = link->out_queue_size;
 898         uint sndlim = link->queue_limit[0];
 899         uint imp = tipc_msg_tot_importance(msg);
 900         uint mtu = link->max_pkt;
 901         uint ack = mod(link->next_in_no - 1);
 902         uint seqno = link->next_out_no;
 903         uint bc_last_in = link->owner->bclink.last_in;
 904         struct tipc_media_addr *addr = &link->media_addr;
 905         struct sk_buff *next = buf->next;
 906
 907         /* Match queue limits against msg importance: */
 908         if (unlikely(qsz >= link->queue_limit[imp]))
 909                 return tipc_link_cong(link, buf);
 910
 911         /* Has valid packet limit been used ? */
 912         if (unlikely(psz > mtu)) {
 913                 kfree_skb_list(buf);
 914                 return -EMSGSIZE;
 915         }
 916
 917         /* Prepare each packet for sending, and add to outqueue: */
 918         while (buf) {
 919                 next = buf->next;
 920                 msg = buf_msg(buf);
 921                 msg_set_word(msg, 2, ((ack << 16) | mod(seqno)));
 922                 msg_set_bcast_ack(msg, bc_last_in);
 923
 924                 if (!link->first_out) {
 925                         link->first_out = buf;
 926                 } else if (qsz < sndlim) {
 927                         link->last_out->next = buf;
 928                 } else if (tipc_msg_bundle(link->last_out, buf, mtu)) {
 929                         link->stats.sent_bundled++;
 930                         buf = next;
 931                         next = buf->next;
 932                         continue;
 933                 } else if (tipc_msg_make_bundle(&buf, mtu, link->addr)) {
 934                         link->stats.sent_bundled++;
 935                         link->stats.sent_bundles++;
 936                         link->last_out->next = buf;
 937                         if (!link->next_out)
 938                                 link->next_out = buf;
 939                 } else {
 940                         link->last_out->next = buf;
 941                         if (!link->next_out)
 942                                 link->next_out = buf;
 943                 }
 944
 945                 /* Send packet if possible: */
 946                 if (likely(++qsz <= sndlim)) {
 947                         tipc_bearer_send(link->bearer_id, buf, addr);
 948                         link->next_out = next;
 949                         link->unacked_window = 0;
 950                 }
 951                 seqno++;
 952                 link->last_out = buf;
 953                 buf = next;
 954         }
 955         link->next_out_no = seqno;
 956         link->out_queue_size = qsz;
 957         return 0;
 958 }
 959
 960 /**
 961  * tipc_link_xmit2() is the general link level function for message sending
 962  * @buf: chain of buffers containing message
 963  * @dsz: amount of user data to be sent
 964  * @dnode: address of destination node
 965  * @selector: a number used for deterministic link selection
 966  * Consumes the buffer chain, except when returning -ELINKCONG
 967  * Returns 0 if success, otherwise errno: -ELINKCONG,-EHOSTUNREACH,-EMSGSIZE
 968  */
 969 int tipc_link_xmit2(struct sk_buff *buf, u32 dnode, u32 selector)
 970 {
 971         struct tipc_link *link = NULL;
 972         struct tipc_node *node;
 973         int rc = -EHOSTUNREACH;
 974
 975         node = tipc_node_find(dnode);
 976         if (node) {
 977                 tipc_node_lock(node);
 978                 link = node->active_links[selector & 1];
 979                 if (link)
 980                         rc = __tipc_link_xmit2(link, buf);
 981                 tipc_node_unlock(node);
 982         }
 983
 984         if (link)
 985                 return rc;
 986
 987         if (likely(in_own_node(dnode)))
 988                 return tipc_sk_rcv(buf);
 989
 990         kfree_skb_list(buf);
 991         return rc;
 992 }
 993
 994 /*
 995  * tipc_link_sync_xmit - synchronize broadcast link endpoints.
 996  *
 997  * Give a newly added peer node the sequence number where it should
 998  * start receiving and acking broadcast packets.
 999  *
1000  * Called with node locked
1001  */
1002 static void tipc_link_sync_xmit(struct tipc_link *l)
1003 {
1004         struct sk_buff *buf;
1005         struct tipc_msg *msg;
1006
1007         buf = tipc_buf_acquire(INT_H_SIZE);
1008         if (!buf)
1009                 return;
1010
1011         msg = buf_msg(buf);
1012         tipc_msg_init(msg, BCAST_PROTOCOL, STATE_MSG, INT_H_SIZE, l->addr);
1013         msg_set_last_bcast(msg, l->owner->bclink.acked);
1014         link_add_chain_to_outqueue(l, buf, 0);
1015         tipc_link_push_queue(l);
1016 }
1017
1018 /*
1019  * tipc_link_sync_rcv - synchronize broadcast link endpoints.
1020  * Receive the sequence number where we should start receiving and
1021  * acking broadcast packets from a newly added peer node, and open
1022  * up for reception of such packets.
1023  *
1024  * Called with node locked
1025  */
1026 static void tipc_link_sync_rcv(struct tipc_node *n, struct sk_buff *buf)
1027 {
1028         struct tipc_msg *msg = buf_msg(buf);
1029
1030         n->bclink.last_sent = n->bclink.last_in = msg_last_bcast(msg);
1031         n->bclink.recv_permitted = true;
1032         kfree_skb(buf);
1033 }
1034
1035 /*
1036  * tipc_link_names_xmit - send name table entries to new neighbor
1037  *
1038  * Send routine for bulk delivery of name table messages when contact
1039  * with a new neighbor occurs. No link congestion checking is performed
1040  * because name table messages *must* be delivered. The messages must be
1041  * small enough not to require fragmentation.
1042  * Called without any locks held.
1043  */
1044 void tipc_link_names_xmit(struct list_head *message_list, u32 dest)
1045 {
1046         struct tipc_node *n_ptr;
1047         struct tipc_link *l_ptr;
1048         struct sk_buff *buf;
1049         struct sk_buff *temp_buf;
1050
1051         if (list_empty(message_list))
1052                 return;
1053
1054         n_ptr = tipc_node_find(dest);
1055         if (n_ptr) {
1056                 tipc_node_lock(n_ptr);
1057                 l_ptr = n_ptr->active_links[0];
1058                 if (l_ptr) {
1059                         /* convert circular list to linear list */
1060                         ((struct sk_buff *)message_list->prev)->next = NULL;
1061                         link_add_chain_to_outqueue(l_ptr,
1062                                 (struct sk_buff *)message_list->next, 0);
1063                         tipc_link_push_queue(l_ptr);
1064                         INIT_LIST_HEAD(message_list);
1065                 }
1066                 tipc_node_unlock(n_ptr);
1067         }
1068
1069         /* discard the messages if they couldn't be sent */
1070         list_for_each_safe(buf, temp_buf, ((struct sk_buff *)message_list)) {
1071                 list_del((struct list_head *)buf);
1072                 kfree_skb(buf);
1073         }
1074 }
1075
1076 /*
1077  * tipc_link_push_packet: Push one unsent packet to the media
1078  */
1079 static u32 tipc_link_push_packet(struct tipc_link *l_ptr)
1080 {
1081         struct sk_buff *buf = l_ptr->first_out;
1082         u32 r_q_size = l_ptr->retransm_queue_size;
1083         u32 r_q_head = l_ptr->retransm_queue_head;
1084
1085         /* Step to position where retransmission failed, if any,    */
1086         /* consider that buffers may have been released in meantime */
1087         if (r_q_size && buf) {
1088                 u32 last = lesser(mod(r_q_head + r_q_size),
1089                                   link_last_sent(l_ptr));
1090                 u32 first = buf_seqno(buf);
1091
1092                 while (buf && less(first, r_q_head)) {
1093                         first = mod(first + 1);
1094                         buf = buf->next;
1095                 }
1096                 l_ptr->retransm_queue_head = r_q_head = first;
1097                 l_ptr->retransm_queue_size = r_q_size = mod(last - first);
1098         }
1099
1100         /* Continue retransmission now, if there is anything: */
1101         if (r_q_size && buf) {
1102                 msg_set_ack(buf_msg(buf), mod(l_ptr->next_in_no - 1));
1103                 msg_set_bcast_ack(buf_msg(buf), l_ptr->owner->bclink.last_in);
1104                 tipc_bearer_send(l_ptr->bearer_id, buf, &l_ptr->media_addr);
1105                 l_ptr->retransm_queue_head = mod(++r_q_head);
1106                 l_ptr->retransm_queue_size = --r_q_size;
1107                 l_ptr->stats.retransmitted++;
1108                 return 0;
1109         }
1110
1111         /* Send deferred protocol message, if any: */
1112         buf = l_ptr->proto_msg_queue;
1113         if (buf) {
1114                 msg_set_ack(buf_msg(buf), mod(l_ptr->next_in_no - 1));
1115                 msg_set_bcast_ack(buf_msg(buf), l_ptr->owner->bclink.last_in);
1116                 tipc_bearer_send(l_ptr->bearer_id, buf, &l_ptr->media_addr);
1117                 l_ptr->unacked_window = 0;
1118                 kfree_skb(buf);
1119                 l_ptr->proto_msg_queue = NULL;
1120                 return 0;
1121         }
1122
1123         /* Send one deferred data message, if send window not full: */
1124         buf = l_ptr->next_out;
1125         if (buf) {
1126                 struct tipc_msg *msg = buf_msg(buf);
1127                 u32 next = msg_seqno(msg);
1128                 u32 first = buf_seqno(l_ptr->first_out);
1129
1130                 if (mod(next - first) < l_ptr->queue_limit[0]) {
1131                         msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1132                         msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1133                         tipc_bearer_send(l_ptr->bearer_id, buf,
1134                                          &l_ptr->media_addr);
1135                         if (msg_user(msg) == MSG_BUNDLER)
1136                                 msg_set_type(msg, BUNDLE_CLOSED);
1137                         l_ptr->next_out = buf->next;
1138                         return 0;
1139                 }
1140         }
1141         return 1;
1142 }
1143
1144 /*
1145  * push_queue(): push out the unsent messages of a link where
1146  *               congestion has abated. Node is locked
1147  */
1148 void tipc_link_push_queue(struct tipc_link *l_ptr)
1149 {
1150         u32 res;
1151
1152         do {
1153                 res = tipc_link_push_packet(l_ptr);
1154         } while (!res);
1155 }
1156
1157 void tipc_link_reset_all(struct tipc_node *node)
1158 {
1159         char addr_string[16];
1160         u32 i;
1161
1162         tipc_node_lock(node);
1163
1164         pr_warn("Resetting all links to %s\n",
1165                 tipc_addr_string_fill(addr_string, node->addr));
1166
1167         for (i = 0; i < MAX_BEARERS; i++) {
1168                 if (node->links[i]) {
1169                         link_print(node->links[i], "Resetting link\n");
1170                         tipc_link_reset(node->links[i]);
1171                 }
1172         }
1173
1174         tipc_node_unlock(node);
1175 }
1176
1177 static void link_retransmit_failure(struct tipc_link *l_ptr,
1178                                     struct sk_buff *buf)
1179 {
1180         struct tipc_msg *msg = buf_msg(buf);
1181
1182         pr_warn("Retransmission failure on link <%s>\n", l_ptr->name);
1183
1184         if (l_ptr->addr) {
1185                 /* Handle failure on standard link */
1186                 link_print(l_ptr, "Resetting link\n");
1187                 tipc_link_reset(l_ptr);
1188
1189         } else {
1190                 /* Handle failure on broadcast link */
1191                 struct tipc_node *n_ptr;
1192                 char addr_string[16];
1193
1194                 pr_info("Msg seq number: %u,  ", msg_seqno(msg));
1195                 pr_cont("Outstanding acks: %lu\n",
1196                         (unsigned long) TIPC_SKB_CB(buf)->handle);
1197
1198                 n_ptr = tipc_bclink_retransmit_to();
1199                 tipc_node_lock(n_ptr);
1200
1201                 tipc_addr_string_fill(addr_string, n_ptr->addr);
1202                 pr_info("Broadcast link info for %s\n", addr_string);
1203                 pr_info("Reception permitted: %d,  Acked: %u\n",
1204                         n_ptr->bclink.recv_permitted,
1205                         n_ptr->bclink.acked);
1206                 pr_info("Last in: %u,  Oos state: %u,  Last sent: %u\n",
1207                         n_ptr->bclink.last_in,
1208                         n_ptr->bclink.oos_state,
1209                         n_ptr->bclink.last_sent);
1210
1211                 tipc_node_unlock(n_ptr);
1212
1213                 tipc_bclink_set_flags(TIPC_BCLINK_RESET);
1214                 l_ptr->stale_count = 0;
1215         }
1216 }
1217
1218 void tipc_link_retransmit(struct tipc_link *l_ptr, struct sk_buff *buf,
1219                           u32 retransmits)
1220 {
1221         struct tipc_msg *msg;
1222
1223         if (!buf)
1224                 return;
1225
1226         msg = buf_msg(buf);
1227
1228         /* Detect repeated retransmit failures */
1229         if (l_ptr->last_retransmitted == msg_seqno(msg)) {
1230                 if (++l_ptr->stale_count > 100) {
1231                         link_retransmit_failure(l_ptr, buf);
1232                         return;
1233                 }
1234         } else {
1235                 l_ptr->last_retransmitted = msg_seqno(msg);
1236                 l_ptr->stale_count = 1;
1237         }
1238
1239         while (retransmits && (buf != l_ptr->next_out) && buf) {
1240                 msg = buf_msg(buf);
1241                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1242                 msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1243                 tipc_bearer_send(l_ptr->bearer_id, buf, &l_ptr->media_addr);
1244                 buf = buf->next;
1245                 retransmits--;
1246                 l_ptr->stats.retransmitted++;
1247         }
1248
1249         l_ptr->retransm_queue_head = l_ptr->retransm_queue_size = 0;
1250 }
1251
1252 /**
1253  * link_insert_deferred_queue - insert deferred messages back into receive chain
1254  */
1255 static struct sk_buff *link_insert_deferred_queue(struct tipc_link *l_ptr,
1256                                                   struct sk_buff *buf)
1257 {
1258         u32 seq_no;
1259
1260         if (l_ptr->oldest_deferred_in == NULL)
1261                 return buf;
1262
1263         seq_no = buf_seqno(l_ptr->oldest_deferred_in);
1264         if (seq_no == mod(l_ptr->next_in_no)) {
1265                 l_ptr->newest_deferred_in->next = buf;
1266                 buf = l_ptr->oldest_deferred_in;
1267                 l_ptr->oldest_deferred_in = NULL;
1268                 l_ptr->deferred_inqueue_sz = 0;
1269         }
1270         return buf;
1271 }
1272
1273 /**
1274  * link_recv_buf_validate - validate basic format of received message
1275  *
1276  * This routine ensures a TIPC message has an acceptable header, and at least
1277  * as much data as the header indicates it should.  The routine also ensures
1278  * that the entire message header is stored in the main fragment of the message
1279  * buffer, to simplify future access to message header fields.
1280  *
1281  * Note: Having extra info present in the message header or data areas is OK.
1282  * TIPC will ignore the excess, under the assumption that it is optional info
1283  * introduced by a later release of the protocol.
1284  */
1285 static int link_recv_buf_validate(struct sk_buff *buf)
1286 {
1287         static u32 min_data_hdr_size[8] = {
1288                 SHORT_H_SIZE, MCAST_H_SIZE, NAMED_H_SIZE, BASIC_H_SIZE,
1289                 MAX_H_SIZE, MAX_H_SIZE, MAX_H_SIZE, MAX_H_SIZE
1290                 };
1291
1292         struct tipc_msg *msg;
1293         u32 tipc_hdr[2];
1294         u32 size;
1295         u32 hdr_size;
1296         u32 min_hdr_size;
1297
1298         /* If this packet comes from the defer queue, the skb has already
1299          * been validated
1300          */
1301         if (unlikely(TIPC_SKB_CB(buf)->deferred))
1302                 return 1;
1303
1304         if (unlikely(buf->len < MIN_H_SIZE))
1305                 return 0;
1306
1307         msg = skb_header_pointer(buf, 0, sizeof(tipc_hdr), tipc_hdr);
1308         if (msg == NULL)
1309                 return 0;
1310
1311         if (unlikely(msg_version(msg) != TIPC_VERSION))
1312                 return 0;
1313
1314         size = msg_size(msg);
1315         hdr_size = msg_hdr_sz(msg);
1316         min_hdr_size = msg_isdata(msg) ?
1317                 min_data_hdr_size[msg_type(msg)] : INT_H_SIZE;
1318
1319         if (unlikely((hdr_size < min_hdr_size) ||
1320                      (size < hdr_size) ||
1321                      (buf->len < size) ||
1322                      (size - hdr_size > TIPC_MAX_USER_MSG_SIZE)))
1323                 return 0;
1324
1325         return pskb_may_pull(buf, hdr_size);
1326 }
1327
1328 /**
1329  * tipc_rcv - process TIPC packets/messages arriving from off-node
1330  * @head: pointer to message buffer chain
1331  * @b_ptr: pointer to bearer message arrived on
1332  *
1333  * Invoked with no locks held.  Bearer pointer must point to a valid bearer
1334  * structure (i.e. cannot be NULL), but bearer can be inactive.
1335  */
1336 void tipc_rcv(struct sk_buff *head, struct tipc_bearer *b_ptr)
1337 {
1338         while (head) {
1339                 struct tipc_node *n_ptr;
1340                 struct tipc_link *l_ptr;
1341                 struct sk_buff *crs;
1342                 struct sk_buff *buf = head;
1343                 struct tipc_msg *msg;
1344                 u32 seq_no;
1345                 u32 ackd;
1346                 u32 released = 0;
1347
1348                 head = head->next;
1349                 buf->next = NULL;
1350
1351                 /* Ensure message is well-formed */
1352                 if (unlikely(!link_recv_buf_validate(buf)))
1353                         goto discard;
1354
1355                 /* Ensure message data is a single contiguous unit */
1356                 if (unlikely(skb_linearize(buf)))
1357                         goto discard;
1358
1359                 /* Handle arrival of a non-unicast link message */
1360                 msg = buf_msg(buf);
1361
1362                 if (unlikely(msg_non_seq(msg))) {
1363                         if (msg_user(msg) ==  LINK_CONFIG)
1364                                 tipc_disc_rcv(buf, b_ptr);
1365                         else
1366                                 tipc_bclink_rcv(buf);
1367                         continue;
1368                 }
1369
1370                 /* Discard unicast link messages destined for another node */
1371                 if (unlikely(!msg_short(msg) &&
1372                              (msg_destnode(msg) != tipc_own_addr)))
1373                         goto discard;
1374
1375                 /* Locate neighboring node that sent message */
1376                 n_ptr = tipc_node_find(msg_prevnode(msg));
1377                 if (unlikely(!n_ptr))
1378                         goto discard;
1379                 tipc_node_lock(n_ptr);
1380
1381                 /* Locate unicast link endpoint that should handle message */
1382                 l_ptr = n_ptr->links[b_ptr->identity];
1383                 if (unlikely(!l_ptr))
1384                         goto unlock_discard;
1385
1386                 /* Verify that communication with node is currently allowed */
1387                 if ((n_ptr->action_flags & TIPC_WAIT_PEER_LINKS_DOWN) &&
1388                     msg_user(msg) == LINK_PROTOCOL &&
1389                     (msg_type(msg) == RESET_MSG ||
1390                     msg_type(msg) == ACTIVATE_MSG) &&
1391                     !msg_redundant_link(msg))
1392                         n_ptr->action_flags &= ~TIPC_WAIT_PEER_LINKS_DOWN;
1393
1394                 if (tipc_node_blocked(n_ptr))
1395                         goto unlock_discard;
1396
1397                 /* Validate message sequence number info */
1398                 seq_no = msg_seqno(msg);
1399                 ackd = msg_ack(msg);
1400
1401                 /* Release acked messages */
1402                 if (n_ptr->bclink.recv_permitted)
1403                         tipc_bclink_acknowledge(n_ptr, msg_bcast_ack(msg));
1404
1405                 crs = l_ptr->first_out;
1406                 while ((crs != l_ptr->next_out) &&
1407                        less_eq(buf_seqno(crs), ackd)) {
1408                         struct sk_buff *next = crs->next;
1409                         kfree_skb(crs);
1410                         crs = next;
1411                         released++;
1412                 }
1413                 if (released) {
1414                         l_ptr->first_out = crs;
1415                         l_ptr->out_queue_size -= released;
1416                 }
1417
1418                 /* Try sending any messages link endpoint has pending */
1419                 if (unlikely(l_ptr->next_out))
1420                         tipc_link_push_queue(l_ptr);
1421
1422                 if (unlikely(!list_empty(&l_ptr->waiting_ports)))
1423                         tipc_link_wakeup_ports(l_ptr, 0);
1424
1425                 /* Process the incoming packet */
1426                 if (unlikely(!link_working_working(l_ptr))) {
1427                         if (msg_user(msg) == LINK_PROTOCOL) {
1428                                 tipc_link_proto_rcv(l_ptr, buf);
1429                                 head = link_insert_deferred_queue(l_ptr, head);
1430                                 tipc_node_unlock(n_ptr);
1431                                 continue;
1432                         }
1433
1434                         /* Traffic message. Conditionally activate link */
1435                         link_state_event(l_ptr, TRAFFIC_MSG_EVT);
1436
1437                         if (link_working_working(l_ptr)) {
1438                                 /* Re-insert buffer in front of queue */
1439                                 buf->next = head;
1440                                 head = buf;
1441                                 tipc_node_unlock(n_ptr);
1442                                 continue;
1443                         }
1444                         goto unlock_discard;
1445                 }
1446
1447                 /* Link is now in state WORKING_WORKING */
1448                 if (unlikely(seq_no != mod(l_ptr->next_in_no))) {
1449                         link_handle_out_of_seq_msg(l_ptr, buf);
1450                         head = link_insert_deferred_queue(l_ptr, head);
1451                         tipc_node_unlock(n_ptr);
1452                         continue;
1453                 }
1454                 l_ptr->next_in_no++;
1455                 if (unlikely(l_ptr->oldest_deferred_in))
1456                         head = link_insert_deferred_queue(l_ptr, head);
1457
1458                 if (unlikely(++l_ptr->unacked_window >= TIPC_MIN_LINK_WIN)) {
1459                         l_ptr->stats.sent_acks++;
1460                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
1461                 }
1462
1463                 if (tipc_link_prepare_input(l_ptr, &buf)) {
1464                         tipc_node_unlock(n_ptr);
1465                         continue;
1466                 }
1467                 tipc_node_unlock(n_ptr);
1468                 msg = buf_msg(buf);
1469                 if (tipc_link_input(l_ptr, buf) != 0)
1470                         goto discard;
1471                 continue;
1472 unlock_discard:
1473                 tipc_node_unlock(n_ptr);
1474 discard:
1475                 kfree_skb(buf);
1476         }
1477 }
1478
1479 /**
1480  * tipc_link_prepare_input - process TIPC link messages
1481  *
1482  * returns nonzero if the message was consumed
1483  *
1484  * Node lock must be held
1485  */
1486 static int tipc_link_prepare_input(struct tipc_link *l, struct sk_buff **buf)
1487 {
1488         struct tipc_node *n;
1489         struct tipc_msg *msg;
1490         int res = -EINVAL;
1491
1492         n = l->owner;
1493         msg = buf_msg(*buf);
1494         switch (msg_user(msg)) {
1495         case CHANGEOVER_PROTOCOL:
1496                 if (tipc_link_tunnel_rcv(n, buf))
1497                         res = 0;
1498                 break;
1499         case MSG_FRAGMENTER:
1500                 l->stats.recv_fragments++;
1501                 if (tipc_buf_append(&l->reasm_buf, buf)) {
1502                         l->stats.recv_fragmented++;
1503                         res = 0;
1504                 } else if (!l->reasm_buf) {
1505                         tipc_link_reset(l);
1506                 }
1507                 break;
1508         case MSG_BUNDLER:
1509                 l->stats.recv_bundles++;
1510                 l->stats.recv_bundled += msg_msgcnt(msg);
1511                 res = 0;
1512                 break;
1513         case NAME_DISTRIBUTOR:
1514                 n->bclink.recv_permitted = true;
1515                 res = 0;
1516                 break;
1517         case BCAST_PROTOCOL:
1518                 tipc_link_sync_rcv(n, *buf);
1519                 break;
1520         default:
1521                 res = 0;
1522         }
1523         return res;
1524 }
1525 /**
1526  * tipc_link_input - Deliver message too higher layers
1527  */
1528 static int tipc_link_input(struct tipc_link *l, struct sk_buff *buf)
1529 {
1530         struct tipc_msg *msg = buf_msg(buf);
1531         int res = 0;
1532
1533         switch (msg_user(msg)) {
1534         case TIPC_LOW_IMPORTANCE:
1535         case TIPC_MEDIUM_IMPORTANCE:
1536         case TIPC_HIGH_IMPORTANCE:
1537         case TIPC_CRITICAL_IMPORTANCE:
1538         case CONN_MANAGER:
1539                 tipc_sk_rcv(buf);
1540                 break;
1541         case NAME_DISTRIBUTOR:
1542                 tipc_named_rcv(buf);
1543                 break;
1544         case MSG_BUNDLER:
1545                 tipc_link_bundle_rcv(buf);
1546                 break;
1547         default:
1548                 res = -EINVAL;
1549         }
1550         return res;
1551 }
1552
1553 /**
1554  * tipc_link_defer_pkt - Add out-of-sequence message to deferred reception queue
1555  *
1556  * Returns increase in queue length (i.e. 0 or 1)
1557  */
1558 u32 tipc_link_defer_pkt(struct sk_buff **head, struct sk_buff **tail,
1559                         struct sk_buff *buf)
1560 {
1561         struct sk_buff *queue_buf;
1562         struct sk_buff **prev;
1563         u32 seq_no = buf_seqno(buf);
1564
1565         buf->next = NULL;
1566
1567         /* Empty queue ? */
1568         if (*head == NULL) {
1569                 *head = *tail = buf;
1570                 return 1;
1571         }
1572
1573         /* Last ? */
1574         if (less(buf_seqno(*tail), seq_no)) {
1575                 (*tail)->next = buf;
1576                 *tail = buf;
1577                 return 1;
1578         }
1579
1580         /* Locate insertion point in queue, then insert; discard if duplicate */
1581         prev = head;
1582         queue_buf = *head;
1583         for (;;) {
1584                 u32 curr_seqno = buf_seqno(queue_buf);
1585
1586                 if (seq_no == curr_seqno) {
1587                         kfree_skb(buf);
1588                         return 0;
1589                 }
1590
1591                 if (less(seq_no, curr_seqno))
1592                         break;
1593
1594                 prev = &queue_buf->next;
1595                 queue_buf = queue_buf->next;
1596         }
1597
1598         buf->next = queue_buf;
1599         *prev = buf;
1600         return 1;
1601 }
1602
1603 /*
1604  * link_handle_out_of_seq_msg - handle arrival of out-of-sequence packet
1605  */
1606 static void link_handle_out_of_seq_msg(struct tipc_link *l_ptr,
1607                                        struct sk_buff *buf)
1608 {
1609         u32 seq_no = buf_seqno(buf);
1610
1611         if (likely(msg_user(buf_msg(buf)) == LINK_PROTOCOL)) {
1612                 tipc_link_proto_rcv(l_ptr, buf);
1613                 return;
1614         }
1615
1616         /* Record OOS packet arrival (force mismatch on next timeout) */
1617         l_ptr->checkpoint--;
1618
1619         /*
1620          * Discard packet if a duplicate; otherwise add it to deferred queue
1621          * and notify peer of gap as per protocol specification
1622          */
1623         if (less(seq_no, mod(l_ptr->next_in_no))) {
1624                 l_ptr->stats.duplicates++;
1625                 kfree_skb(buf);
1626                 return;
1627         }
1628
1629         if (tipc_link_defer_pkt(&l_ptr->oldest_deferred_in,
1630                                 &l_ptr->newest_deferred_in, buf)) {
1631                 l_ptr->deferred_inqueue_sz++;
1632                 l_ptr->stats.deferred_recv++;
1633                 TIPC_SKB_CB(buf)->deferred = true;
1634                 if ((l_ptr->deferred_inqueue_sz % 16) == 1)
1635                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
1636         } else
1637                 l_ptr->stats.duplicates++;
1638 }
1639
1640 /*
1641  * Send protocol message to the other endpoint.
1642  */
1643 void tipc_link_proto_xmit(struct tipc_link *l_ptr, u32 msg_typ, int probe_msg,
1644                           u32 gap, u32 tolerance, u32 priority, u32 ack_mtu)
1645 {
1646         struct sk_buff *buf = NULL;
1647         struct tipc_msg *msg = l_ptr->pmsg;
1648         u32 msg_size = sizeof(l_ptr->proto_msg);
1649         int r_flag;
1650
1651         /* Discard any previous message that was deferred due to congestion */
1652         if (l_ptr->proto_msg_queue) {
1653                 kfree_skb(l_ptr->proto_msg_queue);
1654                 l_ptr->proto_msg_queue = NULL;
1655         }
1656
1657         /* Don't send protocol message during link changeover */
1658         if (l_ptr->exp_msg_count)
1659                 return;
1660
1661         /* Abort non-RESET send if communication with node is prohibited */
1662         if ((tipc_node_blocked(l_ptr->owner)) && (msg_typ != RESET_MSG))
1663                 return;
1664
1665         /* Create protocol message with "out-of-sequence" sequence number */
1666         msg_set_type(msg, msg_typ);
1667         msg_set_net_plane(msg, l_ptr->net_plane);
1668         msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1669         msg_set_last_bcast(msg, tipc_bclink_get_last_sent());
1670
1671         if (msg_typ == STATE_MSG) {
1672                 u32 next_sent = mod(l_ptr->next_out_no);
1673
1674                 if (!tipc_link_is_up(l_ptr))
1675                         return;
1676                 if (l_ptr->next_out)
1677                         next_sent = buf_seqno(l_ptr->next_out);
1678                 msg_set_next_sent(msg, next_sent);
1679                 if (l_ptr->oldest_deferred_in) {
1680                         u32 rec = buf_seqno(l_ptr->oldest_deferred_in);
1681                         gap = mod(rec - mod(l_ptr->next_in_no));
1682                 }
1683                 msg_set_seq_gap(msg, gap);
1684                 if (gap)
1685                         l_ptr->stats.sent_nacks++;
1686                 msg_set_link_tolerance(msg, tolerance);
1687                 msg_set_linkprio(msg, priority);
1688                 msg_set_max_pkt(msg, ack_mtu);
1689                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1690                 msg_set_probe(msg, probe_msg != 0);
1691                 if (probe_msg) {
1692                         u32 mtu = l_ptr->max_pkt;
1693
1694                         if ((mtu < l_ptr->max_pkt_target) &&
1695                             link_working_working(l_ptr) &&
1696                             l_ptr->fsm_msg_cnt) {
1697                                 msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
1698                                 if (l_ptr->max_pkt_probes == 10) {
1699                                         l_ptr->max_pkt_target = (msg_size - 4);
1700                                         l_ptr->max_pkt_probes = 0;
1701                                         msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
1702                                 }
1703                                 l_ptr->max_pkt_probes++;
1704                         }
1705
1706                         l_ptr->stats.sent_probes++;
1707                 }
1708                 l_ptr->stats.sent_states++;
1709         } else {                /* RESET_MSG or ACTIVATE_MSG */
1710                 msg_set_ack(msg, mod(l_ptr->reset_checkpoint - 1));
1711                 msg_set_seq_gap(msg, 0);
1712                 msg_set_next_sent(msg, 1);
1713                 msg_set_probe(msg, 0);
1714                 msg_set_link_tolerance(msg, l_ptr->tolerance);
1715                 msg_set_linkprio(msg, l_ptr->priority);
1716                 msg_set_max_pkt(msg, l_ptr->max_pkt_target);
1717         }
1718
1719         r_flag = (l_ptr->owner->working_links > tipc_link_is_up(l_ptr));
1720         msg_set_redundant_link(msg, r_flag);
1721         msg_set_linkprio(msg, l_ptr->priority);
1722         msg_set_size(msg, msg_size);
1723
1724         msg_set_seqno(msg, mod(l_ptr->next_out_no + (0xffff/2)));
1725
1726         buf = tipc_buf_acquire(msg_size);
1727         if (!buf)
1728                 return;
1729
1730         skb_copy_to_linear_data(buf, msg, sizeof(l_ptr->proto_msg));
1731         buf->priority = TC_PRIO_CONTROL;
1732
1733         tipc_bearer_send(l_ptr->bearer_id, buf, &l_ptr->media_addr);
1734         l_ptr->unacked_window = 0;
1735         kfree_skb(buf);
1736 }
1737
1738 /*
1739  * Receive protocol message :
1740  * Note that network plane id propagates through the network, and may
1741  * change at any time. The node with lowest address rules
1742  */
1743 static void tipc_link_proto_rcv(struct tipc_link *l_ptr, struct sk_buff *buf)
1744 {
1745         u32 rec_gap = 0;
1746         u32 max_pkt_info;
1747         u32 max_pkt_ack;
1748         u32 msg_tol;
1749         struct tipc_msg *msg = buf_msg(buf);
1750
1751         /* Discard protocol message during link changeover */
1752         if (l_ptr->exp_msg_count)
1753                 goto exit;
1754
1755         if (l_ptr->net_plane != msg_net_plane(msg))
1756                 if (tipc_own_addr > msg_prevnode(msg))
1757                         l_ptr->net_plane = msg_net_plane(msg);
1758
1759         switch (msg_type(msg)) {
1760
1761         case RESET_MSG:
1762                 if (!link_working_unknown(l_ptr) &&
1763                     (l_ptr->peer_session != INVALID_SESSION)) {
1764                         if (less_eq(msg_session(msg), l_ptr->peer_session))
1765                                 break; /* duplicate or old reset: ignore */
1766                 }
1767
1768                 if (!msg_redundant_link(msg) && (link_working_working(l_ptr) ||
1769                                 link_working_unknown(l_ptr))) {
1770                         /*
1771                          * peer has lost contact -- don't allow peer's links
1772                          * to reactivate before we recognize loss & clean up
1773                          */
1774                         l_ptr->owner->action_flags |= TIPC_WAIT_OWN_LINKS_DOWN;
1775                 }
1776
1777                 link_state_event(l_ptr, RESET_MSG);
1778
1779                 /* fall thru' */
1780         case ACTIVATE_MSG:
1781                 /* Update link settings according other endpoint's values */
1782                 strcpy((strrchr(l_ptr->name, ':') + 1), (char *)msg_data(msg));
1783
1784                 msg_tol = msg_link_tolerance(msg);
1785                 if (msg_tol > l_ptr->tolerance)
1786                         link_set_supervision_props(l_ptr, msg_tol);
1787
1788                 if (msg_linkprio(msg) > l_ptr->priority)
1789                         l_ptr->priority = msg_linkprio(msg);
1790
1791                 max_pkt_info = msg_max_pkt(msg);
1792                 if (max_pkt_info) {
1793                         if (max_pkt_info < l_ptr->max_pkt_target)
1794                                 l_ptr->max_pkt_target = max_pkt_info;
1795                         if (l_ptr->max_pkt > l_ptr->max_pkt_target)
1796                                 l_ptr->max_pkt = l_ptr->max_pkt_target;
1797                 } else {
1798                         l_ptr->max_pkt = l_ptr->max_pkt_target;
1799                 }
1800
1801                 /* Synchronize broadcast link info, if not done previously */
1802                 if (!tipc_node_is_up(l_ptr->owner)) {
1803                         l_ptr->owner->bclink.last_sent =
1804                                 l_ptr->owner->bclink.last_in =
1805                                 msg_last_bcast(msg);
1806                         l_ptr->owner->bclink.oos_state = 0;
1807                 }
1808
1809                 l_ptr->peer_session = msg_session(msg);
1810                 l_ptr->peer_bearer_id = msg_bearer_id(msg);
1811
1812                 if (msg_type(msg) == ACTIVATE_MSG)
1813                         link_state_event(l_ptr, ACTIVATE_MSG);
1814                 break;
1815         case STATE_MSG:
1816
1817                 msg_tol = msg_link_tolerance(msg);
1818                 if (msg_tol)
1819                         link_set_supervision_props(l_ptr, msg_tol);
1820
1821                 if (msg_linkprio(msg) &&
1822                     (msg_linkprio(msg) != l_ptr->priority)) {
1823                         pr_warn("%s<%s>, priority change %u->%u\n",
1824                                 link_rst_msg, l_ptr->name, l_ptr->priority,
1825                                 msg_linkprio(msg));
1826                         l_ptr->priority = msg_linkprio(msg);
1827                         tipc_link_reset(l_ptr); /* Enforce change to take effect */
1828                         break;
1829                 }
1830
1831                 /* Record reception; force mismatch at next timeout: */
1832                 l_ptr->checkpoint--;
1833
1834                 link_state_event(l_ptr, TRAFFIC_MSG_EVT);
1835                 l_ptr->stats.recv_states++;
1836                 if (link_reset_unknown(l_ptr))
1837                         break;
1838
1839                 if (less_eq(mod(l_ptr->next_in_no), msg_next_sent(msg))) {
1840                         rec_gap = mod(msg_next_sent(msg) -
1841                                       mod(l_ptr->next_in_no));
1842                 }
1843
1844                 max_pkt_ack = msg_max_pkt(msg);
1845                 if (max_pkt_ack > l_ptr->max_pkt) {
1846                         l_ptr->max_pkt = max_pkt_ack;
1847                         l_ptr->max_pkt_probes = 0;
1848                 }
1849
1850                 max_pkt_ack = 0;
1851                 if (msg_probe(msg)) {
1852                         l_ptr->stats.recv_probes++;
1853                         if (msg_size(msg) > sizeof(l_ptr->proto_msg))
1854                                 max_pkt_ack = msg_size(msg);
1855                 }
1856
1857                 /* Protocol message before retransmits, reduce loss risk */
1858                 if (l_ptr->owner->bclink.recv_permitted)
1859                         tipc_bclink_update_link_state(l_ptr->owner,
1860                                                       msg_last_bcast(msg));
1861
1862                 if (rec_gap || (msg_probe(msg))) {
1863                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, rec_gap, 0,
1864                                              0, max_pkt_ack);
1865                 }
1866                 if (msg_seq_gap(msg)) {
1867                         l_ptr->stats.recv_nacks++;
1868                         tipc_link_retransmit(l_ptr, l_ptr->first_out,
1869                                              msg_seq_gap(msg));
1870                 }
1871                 break;
1872         }
1873 exit:
1874         kfree_skb(buf);
1875 }
1876
1877
1878 /* tipc_link_tunnel_xmit(): Tunnel one packet via a link belonging to
1879  * a different bearer. Owner node is locked.
1880  */
1881 static void tipc_link_tunnel_xmit(struct tipc_link *l_ptr,
1882                                   struct tipc_msg *tunnel_hdr,
1883                                   struct tipc_msg *msg,
1884                                   u32 selector)
1885 {
1886         struct tipc_link *tunnel;
1887         struct sk_buff *buf;
1888         u32 length = msg_size(msg);
1889
1890         tunnel = l_ptr->owner->active_links[selector & 1];
1891         if (!tipc_link_is_up(tunnel)) {
1892                 pr_warn("%stunnel link no longer available\n", link_co_err);
1893                 return;
1894         }
1895         msg_set_size(tunnel_hdr, length + INT_H_SIZE);
1896         buf = tipc_buf_acquire(length + INT_H_SIZE);
1897         if (!buf) {
1898                 pr_warn("%sunable to send tunnel msg\n", link_co_err);
1899                 return;
1900         }
1901         skb_copy_to_linear_data(buf, tunnel_hdr, INT_H_SIZE);
1902         skb_copy_to_linear_data_offset(buf, INT_H_SIZE, msg, length);
1903         __tipc_link_xmit(tunnel, buf);
1904 }
1905
1906
1907 /* tipc_link_failover_send_queue(): A link has gone down, but a second
1908  * link is still active. We can do failover. Tunnel the failing link's
1909  * whole send queue via the remaining link. This way, we don't lose
1910  * any packets, and sequence order is preserved for subsequent traffic
1911  * sent over the remaining link. Owner node is locked.
1912  */
1913 void tipc_link_failover_send_queue(struct tipc_link *l_ptr)
1914 {
1915         u32 msgcount = l_ptr->out_queue_size;
1916         struct sk_buff *crs = l_ptr->first_out;
1917         struct tipc_link *tunnel = l_ptr->owner->active_links[0];
1918         struct tipc_msg tunnel_hdr;
1919         int split_bundles;
1920
1921         if (!tunnel)
1922                 return;
1923
1924         tipc_msg_init(&tunnel_hdr, CHANGEOVER_PROTOCOL,
1925                  ORIGINAL_MSG, INT_H_SIZE, l_ptr->addr);
1926         msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
1927         msg_set_msgcnt(&tunnel_hdr, msgcount);
1928
1929         if (!l_ptr->first_out) {
1930                 struct sk_buff *buf;
1931
1932                 buf = tipc_buf_acquire(INT_H_SIZE);
1933                 if (buf) {
1934                         skb_copy_to_linear_data(buf, &tunnel_hdr, INT_H_SIZE);
1935                         msg_set_size(&tunnel_hdr, INT_H_SIZE);
1936                         __tipc_link_xmit(tunnel, buf);
1937                 } else {
1938                         pr_warn("%sunable to send changeover msg\n",
1939                                 link_co_err);
1940                 }
1941                 return;
1942         }
1943
1944         split_bundles = (l_ptr->owner->active_links[0] !=
1945                          l_ptr->owner->active_links[1]);
1946
1947         while (crs) {
1948                 struct tipc_msg *msg = buf_msg(crs);
1949
1950                 if ((msg_user(msg) == MSG_BUNDLER) && split_bundles) {
1951                         struct tipc_msg *m = msg_get_wrapped(msg);
1952                         unchar *pos = (unchar *)m;
1953
1954                         msgcount = msg_msgcnt(msg);
1955                         while (msgcount--) {
1956                                 msg_set_seqno(m, msg_seqno(msg));
1957                                 tipc_link_tunnel_xmit(l_ptr, &tunnel_hdr, m,
1958                                                       msg_link_selector(m));
1959                                 pos += align(msg_size(m));
1960                                 m = (struct tipc_msg *)pos;
1961                         }
1962                 } else {
1963                         tipc_link_tunnel_xmit(l_ptr, &tunnel_hdr, msg,
1964                                               msg_link_selector(msg));
1965                 }
1966                 crs = crs->next;
1967         }
1968 }
1969
1970 /* tipc_link_dup_queue_xmit(): A second link has become active. Tunnel a
1971  * duplicate of the first link's send queue via the new link. This way, we
1972  * are guaranteed that currently queued packets from a socket are delivered
1973  * before future traffic from the same socket, even if this is using the
1974  * new link. The last arriving copy of each duplicate packet is dropped at
1975  * the receiving end by the regular protocol check, so packet cardinality
1976  * and sequence order is preserved per sender/receiver socket pair.
1977  * Owner node is locked.
1978  */
1979 void tipc_link_dup_queue_xmit(struct tipc_link *l_ptr,
1980                               struct tipc_link *tunnel)
1981 {
1982         struct sk_buff *iter;
1983         struct tipc_msg tunnel_hdr;
1984
1985         tipc_msg_init(&tunnel_hdr, CHANGEOVER_PROTOCOL,
1986                  DUPLICATE_MSG, INT_H_SIZE, l_ptr->addr);
1987         msg_set_msgcnt(&tunnel_hdr, l_ptr->out_queue_size);
1988         msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
1989         iter = l_ptr->first_out;
1990         while (iter) {
1991                 struct sk_buff *outbuf;
1992                 struct tipc_msg *msg = buf_msg(iter);
1993                 u32 length = msg_size(msg);
1994
1995                 if (msg_user(msg) == MSG_BUNDLER)
1996                         msg_set_type(msg, CLOSED_MSG);
1997                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));   /* Update */
1998                 msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1999                 msg_set_size(&tunnel_hdr, length + INT_H_SIZE);
2000                 outbuf = tipc_buf_acquire(length + INT_H_SIZE);
2001                 if (outbuf == NULL) {
2002                         pr_warn("%sunable to send duplicate msg\n",
2003                                 link_co_err);
2004                         return;
2005                 }
2006                 skb_copy_to_linear_data(outbuf, &tunnel_hdr, INT_H_SIZE);
2007                 skb_copy_to_linear_data_offset(outbuf, INT_H_SIZE, iter->data,
2008                                                length);
2009                 __tipc_link_xmit(tunnel, outbuf);
2010                 if (!tipc_link_is_up(l_ptr))
2011                         return;
2012                 iter = iter->next;
2013         }
2014 }
2015
2016 /**
2017  * buf_extract - extracts embedded TIPC message from another message
2018  * @skb: encapsulating message buffer
2019  * @from_pos: offset to extract from
2020  *
2021  * Returns a new message buffer containing an embedded message.  The
2022  * encapsulating message itself is left unchanged.
2023  */
2024 static struct sk_buff *buf_extract(struct sk_buff *skb, u32 from_pos)
2025 {
2026         struct tipc_msg *msg = (struct tipc_msg *)(skb->data + from_pos);
2027         u32 size = msg_size(msg);
2028         struct sk_buff *eb;
2029
2030         eb = tipc_buf_acquire(size);
2031         if (eb)
2032                 skb_copy_to_linear_data(eb, msg, size);
2033         return eb;
2034 }
2035
2036
2037
2038 /* tipc_link_dup_rcv(): Receive a tunnelled DUPLICATE_MSG packet.
2039  * Owner node is locked.
2040  */
2041 static void tipc_link_dup_rcv(struct tipc_link *l_ptr,
2042                               struct sk_buff *t_buf)
2043 {
2044         struct sk_buff *buf;
2045
2046         if (!tipc_link_is_up(l_ptr))
2047                 return;
2048
2049         buf = buf_extract(t_buf, INT_H_SIZE);
2050         if (buf == NULL) {
2051                 pr_warn("%sfailed to extract inner dup pkt\n", link_co_err);
2052                 return;
2053         }
2054
2055         /* Add buffer to deferred queue, if applicable: */
2056         link_handle_out_of_seq_msg(l_ptr, buf);
2057 }
2058
2059 /*  tipc_link_failover_rcv(): Receive a tunnelled ORIGINAL_MSG packet
2060  *  Owner node is locked.
2061  */
2062 static struct sk_buff *tipc_link_failover_rcv(struct tipc_link *l_ptr,
2063                                               struct sk_buff *t_buf)
2064 {
2065         struct tipc_msg *t_msg = buf_msg(t_buf);
2066         struct sk_buff *buf = NULL;
2067         struct tipc_msg *msg;
2068
2069         if (tipc_link_is_up(l_ptr))
2070                 tipc_link_reset(l_ptr);
2071
2072         /* First failover packet? */
2073         if (l_ptr->exp_msg_count == START_CHANGEOVER)
2074                 l_ptr->exp_msg_count = msg_msgcnt(t_msg);
2075
2076         /* Should there be an inner packet? */
2077         if (l_ptr->exp_msg_count) {
2078                 l_ptr->exp_msg_count--;
2079                 buf = buf_extract(t_buf, INT_H_SIZE);
2080                 if (buf == NULL) {
2081                         pr_warn("%sno inner failover pkt\n", link_co_err);
2082                         goto exit;
2083                 }
2084                 msg = buf_msg(buf);
2085
2086                 if (less(msg_seqno(msg), l_ptr->reset_checkpoint)) {
2087                         kfree_skb(buf);
2088                         buf = NULL;
2089                         goto exit;
2090                 }
2091                 if (msg_user(msg) == MSG_FRAGMENTER) {
2092                         l_ptr->stats.recv_fragments++;
2093                         tipc_buf_append(&l_ptr->reasm_buf, &buf);
2094                 }
2095         }
2096 exit:
2097         if ((l_ptr->exp_msg_count == 0) && (l_ptr->flags & LINK_STOPPED)) {
2098                 tipc_node_detach_link(l_ptr->owner, l_ptr);
2099                 kfree(l_ptr);
2100         }
2101         return buf;
2102 }
2103
2104 /*  tipc_link_tunnel_rcv(): Receive a tunnelled packet, sent
2105  *  via other link as result of a failover (ORIGINAL_MSG) or
2106  *  a new active link (DUPLICATE_MSG). Failover packets are
2107  *  returned to the active link for delivery upwards.
2108  *  Owner node is locked.
2109  */
2110 static int tipc_link_tunnel_rcv(struct tipc_node *n_ptr,
2111                                 struct sk_buff **buf)
2112 {
2113         struct sk_buff *t_buf = *buf;
2114         struct tipc_link *l_ptr;
2115         struct tipc_msg *t_msg = buf_msg(t_buf);
2116         u32 bearer_id = msg_bearer_id(t_msg);
2117
2118         *buf = NULL;
2119
2120         if (bearer_id >= MAX_BEARERS)
2121                 goto exit;
2122
2123         l_ptr = n_ptr->links[bearer_id];
2124         if (!l_ptr)
2125                 goto exit;
2126
2127         if (msg_type(t_msg) == DUPLICATE_MSG)
2128                 tipc_link_dup_rcv(l_ptr, t_buf);
2129         else if (msg_type(t_msg) == ORIGINAL_MSG)
2130                 *buf = tipc_link_failover_rcv(l_ptr, t_buf);
2131         else
2132                 pr_warn("%sunknown tunnel pkt received\n", link_co_err);
2133 exit:
2134         kfree_skb(t_buf);
2135         return *buf != NULL;
2136 }
2137
2138 /*
2139  *  Bundler functionality:
2140  */
2141 void tipc_link_bundle_rcv(struct sk_buff *buf)
2142 {
2143         u32 msgcount = msg_msgcnt(buf_msg(buf));
2144         u32 pos = INT_H_SIZE;
2145         struct sk_buff *obuf;
2146         struct tipc_msg *omsg;
2147
2148         while (msgcount--) {
2149                 obuf = buf_extract(buf, pos);
2150                 if (obuf == NULL) {
2151                         pr_warn("Link unable to unbundle message(s)\n");
2152                         break;
2153                 }
2154                 omsg = buf_msg(obuf);
2155                 pos += align(msg_size(omsg));
2156                 if (msg_isdata(omsg) || (msg_user(omsg) == CONN_MANAGER)) {
2157                         tipc_sk_rcv(obuf);
2158                 } else if (msg_user(omsg) == NAME_DISTRIBUTOR) {
2159                         tipc_named_rcv(obuf);
2160                 } else {
2161                         pr_warn("Illegal bundled msg: %u\n", msg_user(omsg));
2162                         kfree_skb(obuf);
2163                 }
2164         }
2165         kfree_skb(buf);
2166 }
2167
2168 /*
2169  *  Fragmentation/defragmentation:
2170  */
2171
2172 /*
2173  * tipc_link_frag_xmit: Entry for buffers needing fragmentation.
2174  * The buffer is complete, inclusive total message length.
2175  * Returns user data length.
2176  */
2177 static int tipc_link_frag_xmit(struct tipc_link *l_ptr, struct sk_buff *buf)
2178 {
2179         struct sk_buff *buf_chain = NULL;
2180         struct sk_buff *buf_chain_tail = (struct sk_buff *)&buf_chain;
2181         struct tipc_msg *inmsg = buf_msg(buf);
2182         struct tipc_msg fragm_hdr;
2183         u32 insize = msg_size(inmsg);
2184         u32 dsz = msg_data_sz(inmsg);
2185         unchar *crs = buf->data;
2186         u32 rest = insize;
2187         u32 pack_sz = l_ptr->max_pkt;
2188         u32 fragm_sz = pack_sz - INT_H_SIZE;
2189         u32 fragm_no = 0;
2190         u32 destaddr;
2191
2192         if (msg_short(inmsg))
2193                 destaddr = l_ptr->addr;
2194         else
2195                 destaddr = msg_destnode(inmsg);
2196
2197         /* Prepare reusable fragment header: */
2198         tipc_msg_init(&fragm_hdr, MSG_FRAGMENTER, FIRST_FRAGMENT,
2199                  INT_H_SIZE, destaddr);
2200
2201         /* Chop up message: */
2202         while (rest > 0) {
2203                 struct sk_buff *fragm;
2204
2205                 if (rest <= fragm_sz) {
2206                         fragm_sz = rest;
2207                         msg_set_type(&fragm_hdr, LAST_FRAGMENT);
2208                 }
2209                 fragm = tipc_buf_acquire(fragm_sz + INT_H_SIZE);
2210                 if (fragm == NULL) {
2211                         kfree_skb(buf);
2212                         kfree_skb_list(buf_chain);
2213                         return -ENOMEM;
2214                 }
2215                 msg_set_size(&fragm_hdr, fragm_sz + INT_H_SIZE);
2216                 fragm_no++;
2217                 msg_set_fragm_no(&fragm_hdr, fragm_no);
2218                 skb_copy_to_linear_data(fragm, &fragm_hdr, INT_H_SIZE);
2219                 skb_copy_to_linear_data_offset(fragm, INT_H_SIZE, crs,
2220                                                fragm_sz);
2221                 buf_chain_tail->next = fragm;
2222                 buf_chain_tail = fragm;
2223
2224                 rest -= fragm_sz;
2225                 crs += fragm_sz;
2226                 msg_set_type(&fragm_hdr, FRAGMENT);
2227         }
2228         kfree_skb(buf);
2229
2230         /* Append chain of fragments to send queue & send them */
2231         l_ptr->long_msg_seq_no++;
2232         link_add_chain_to_outqueue(l_ptr, buf_chain, l_ptr->long_msg_seq_no);
2233         l_ptr->stats.sent_fragments += fragm_no;
2234         l_ptr->stats.sent_fragmented++;
2235         tipc_link_push_queue(l_ptr);
2236
2237         return dsz;
2238 }
2239
2240 static void link_set_supervision_props(struct tipc_link *l_ptr, u32 tolerance)
2241 {
2242         if ((tolerance < TIPC_MIN_LINK_TOL) || (tolerance > TIPC_MAX_LINK_TOL))
2243                 return;
2244
2245         l_ptr->tolerance = tolerance;
2246         l_ptr->continuity_interval =
2247                 ((tolerance / 4) > 500) ? 500 : tolerance / 4;
2248         l_ptr->abort_limit = tolerance / (l_ptr->continuity_interval / 4);
2249 }
2250
2251 void tipc_link_set_queue_limits(struct tipc_link *l_ptr, u32 window)
2252 {
2253         /* Data messages from this node, inclusive FIRST_FRAGM */
2254         l_ptr->queue_limit[TIPC_LOW_IMPORTANCE] = window;
2255         l_ptr->queue_limit[TIPC_MEDIUM_IMPORTANCE] = (window / 3) * 4;
2256         l_ptr->queue_limit[TIPC_HIGH_IMPORTANCE] = (window / 3) * 5;
2257         l_ptr->queue_limit[TIPC_CRITICAL_IMPORTANCE] = (window / 3) * 6;
2258         /* Transiting data messages,inclusive FIRST_FRAGM */
2259         l_ptr->queue_limit[TIPC_LOW_IMPORTANCE + 4] = 300;
2260         l_ptr->queue_limit[TIPC_MEDIUM_IMPORTANCE + 4] = 600;
2261         l_ptr->queue_limit[TIPC_HIGH_IMPORTANCE + 4] = 900;
2262         l_ptr->queue_limit[TIPC_CRITICAL_IMPORTANCE + 4] = 1200;
2263         l_ptr->queue_limit[CONN_MANAGER] = 1200;
2264         l_ptr->queue_limit[CHANGEOVER_PROTOCOL] = 2500;
2265         l_ptr->queue_limit[NAME_DISTRIBUTOR] = 3000;
2266         /* FRAGMENT and LAST_FRAGMENT packets */
2267         l_ptr->queue_limit[MSG_FRAGMENTER] = 4000;
2268 }
2269
2270 /* tipc_link_find_owner - locate owner node of link by link's name
2271  * @name: pointer to link name string
2272  * @bearer_id: pointer to index in 'node->links' array where the link was found.
2273  *
2274  * Returns pointer to node owning the link, or 0 if no matching link is found.
2275  */
2276 static struct tipc_node *tipc_link_find_owner(const char *link_name,
2277                                               unsigned int *bearer_id)
2278 {
2279         struct tipc_link *l_ptr;
2280         struct tipc_node *n_ptr;
2281         struct tipc_node *found_node = 0;
2282         int i;
2283
2284         *bearer_id = 0;
2285         rcu_read_lock();
2286         list_for_each_entry_rcu(n_ptr, &tipc_node_list, list) {
2287                 tipc_node_lock(n_ptr);
2288                 for (i = 0; i < MAX_BEARERS; i++) {
2289                         l_ptr = n_ptr->links[i];
2290                         if (l_ptr && !strcmp(l_ptr->name, link_name)) {
2291                                 *bearer_id = i;
2292                                 found_node = n_ptr;
2293                                 break;
2294                         }
2295                 }
2296                 tipc_node_unlock(n_ptr);
2297                 if (found_node)
2298                         break;
2299         }
2300         rcu_read_unlock();
2301
2302         return found_node;
2303 }
2304
2305 /**
2306  * link_value_is_valid -- validate proposed link tolerance/priority/window
2307  *
2308  * @cmd: value type (TIPC_CMD_SET_LINK_*)
2309  * @new_value: the new value
2310  *
2311  * Returns 1 if value is within range, 0 if not.
2312  */
2313 static int link_value_is_valid(u16 cmd, u32 new_value)
2314 {
2315         switch (cmd) {
2316         case TIPC_CMD_SET_LINK_TOL:
2317                 return (new_value >= TIPC_MIN_LINK_TOL) &&
2318                         (new_value <= TIPC_MAX_LINK_TOL);
2319         case TIPC_CMD_SET_LINK_PRI:
2320                 return (new_value <= TIPC_MAX_LINK_PRI);
2321         case TIPC_CMD_SET_LINK_WINDOW:
2322                 return (new_value >= TIPC_MIN_LINK_WIN) &&
2323                         (new_value <= TIPC_MAX_LINK_WIN);
2324         }
2325         return 0;
2326 }
2327
2328 /**
2329  * link_cmd_set_value - change priority/tolerance/window for link/bearer/media
2330  * @name: ptr to link, bearer, or media name
2331  * @new_value: new value of link, bearer, or media setting
2332  * @cmd: which link, bearer, or media attribute to set (TIPC_CMD_SET_LINK_*)
2333  *
2334  * Caller must hold RTNL lock to ensure link/bearer/media is not deleted.
2335  *
2336  * Returns 0 if value updated and negative value on error.
2337  */
2338 static int link_cmd_set_value(const char *name, u32 new_value, u16 cmd)
2339 {
2340         struct tipc_node *node;
2341         struct tipc_link *l_ptr;
2342         struct tipc_bearer *b_ptr;
2343         struct tipc_media *m_ptr;
2344         int bearer_id;
2345         int res = 0;
2346
2347         node = tipc_link_find_owner(name, &bearer_id);
2348         if (node) {
2349                 tipc_node_lock(node);
2350                 l_ptr = node->links[bearer_id];
2351
2352                 if (l_ptr) {
2353                         switch (cmd) {
2354                         case TIPC_CMD_SET_LINK_TOL:
2355                                 link_set_supervision_props(l_ptr, new_value);
2356                                 tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, 0,
2357                                                      new_value, 0, 0);
2358                                 break;
2359                         case TIPC_CMD_SET_LINK_PRI:
2360                                 l_ptr->priority = new_value;
2361                                 tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, 0,
2362                                                      0, new_value, 0);
2363                                 break;
2364                         case TIPC_CMD_SET_LINK_WINDOW:
2365                                 tipc_link_set_queue_limits(l_ptr, new_value);
2366                                 break;
2367                         default:
2368                                 res = -EINVAL;
2369                                 break;
2370                         }
2371                 }
2372                 tipc_node_unlock(node);
2373                 return res;
2374         }
2375
2376         b_ptr = tipc_bearer_find(name);
2377         if (b_ptr) {
2378                 switch (cmd) {
2379                 case TIPC_CMD_SET_LINK_TOL:
2380                         b_ptr->tolerance = new_value;
2381                         break;
2382                 case TIPC_CMD_SET_LINK_PRI:
2383                         b_ptr->priority = new_value;
2384                         break;
2385                 case TIPC_CMD_SET_LINK_WINDOW:
2386                         b_ptr->window = new_value;
2387                         break;
2388                 default:
2389                         res = -EINVAL;
2390                         break;
2391                 }
2392                 return res;
2393         }
2394
2395         m_ptr = tipc_media_find(name);
2396         if (!m_ptr)
2397                 return -ENODEV;
2398         switch (cmd) {
2399         case TIPC_CMD_SET_LINK_TOL:
2400                 m_ptr->tolerance = new_value;
2401                 break;
2402         case TIPC_CMD_SET_LINK_PRI:
2403                 m_ptr->priority = new_value;
2404                 break;
2405         case TIPC_CMD_SET_LINK_WINDOW:
2406                 m_ptr->window = new_value;
2407                 break;
2408         default:
2409                 res = -EINVAL;
2410                 break;
2411         }
2412         return res;
2413 }
2414
2415 struct sk_buff *tipc_link_cmd_config(const void *req_tlv_area, int req_tlv_space,
2416                                      u16 cmd)
2417 {
2418         struct tipc_link_config *args;
2419         u32 new_value;
2420         int res;
2421
2422         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_CONFIG))
2423                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2424
2425         args = (struct tipc_link_config *)TLV_DATA(req_tlv_area);
2426         new_value = ntohl(args->value);
2427
2428         if (!link_value_is_valid(cmd, new_value))
2429                 return tipc_cfg_reply_error_string(
2430                         "cannot change, value invalid");
2431
2432         if (!strcmp(args->name, tipc_bclink_name)) {
2433                 if ((cmd == TIPC_CMD_SET_LINK_WINDOW) &&
2434                     (tipc_bclink_set_queue_limits(new_value) == 0))
2435                         return tipc_cfg_reply_none();
2436                 return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
2437                                                    " (cannot change setting on broadcast link)");
2438         }
2439
2440         res = link_cmd_set_value(args->name, new_value, cmd);
2441         if (res)
2442                 return tipc_cfg_reply_error_string("cannot change link setting");
2443
2444         return tipc_cfg_reply_none();
2445 }
2446
2447 /**
2448  * link_reset_statistics - reset link statistics
2449  * @l_ptr: pointer to link
2450  */
2451 static void link_reset_statistics(struct tipc_link *l_ptr)
2452 {
2453         memset(&l_ptr->stats, 0, sizeof(l_ptr->stats));
2454         l_ptr->stats.sent_info = l_ptr->next_out_no;
2455         l_ptr->stats.recv_info = l_ptr->next_in_no;
2456 }
2457
2458 struct sk_buff *tipc_link_cmd_reset_stats(const void *req_tlv_area, int req_tlv_space)
2459 {
2460         char *link_name;
2461         struct tipc_link *l_ptr;
2462         struct tipc_node *node;
2463         unsigned int bearer_id;
2464
2465         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_NAME))
2466                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2467
2468         link_name = (char *)TLV_DATA(req_tlv_area);
2469         if (!strcmp(link_name, tipc_bclink_name)) {
2470                 if (tipc_bclink_reset_stats())
2471                         return tipc_cfg_reply_error_string("link not found");
2472                 return tipc_cfg_reply_none();
2473         }
2474         node = tipc_link_find_owner(link_name, &bearer_id);
2475         if (!node)
2476                 return tipc_cfg_reply_error_string("link not found");
2477
2478         tipc_node_lock(node);
2479         l_ptr = node->links[bearer_id];
2480         if (!l_ptr) {
2481                 tipc_node_unlock(node);
2482                 return tipc_cfg_reply_error_string("link not found");
2483         }
2484         link_reset_statistics(l_ptr);
2485         tipc_node_unlock(node);
2486         return tipc_cfg_reply_none();
2487 }
2488
2489 /**
2490  * percent - convert count to a percentage of total (rounding up or down)
2491  */
2492 static u32 percent(u32 count, u32 total)
2493 {
2494         return (count * 100 + (total / 2)) / total;
2495 }
2496
2497 /**
2498  * tipc_link_stats - print link statistics
2499  * @name: link name
2500  * @buf: print buffer area
2501  * @buf_size: size of print buffer area
2502  *
2503  * Returns length of print buffer data string (or 0 if error)
2504  */
2505 static int tipc_link_stats(const char *name, char *buf, const u32 buf_size)
2506 {
2507         struct tipc_link *l;
2508         struct tipc_stats *s;
2509         struct tipc_node *node;
2510         char *status;
2511         u32 profile_total = 0;
2512         unsigned int bearer_id;
2513         int ret;
2514
2515         if (!strcmp(name, tipc_bclink_name))
2516                 return tipc_bclink_stats(buf, buf_size);
2517
2518         node = tipc_link_find_owner(name, &bearer_id);
2519         if (!node)
2520                 return 0;
2521
2522         tipc_node_lock(node);
2523
2524         l = node->links[bearer_id];
2525         if (!l) {
2526                 tipc_node_unlock(node);
2527                 return 0;
2528         }
2529
2530         s = &l->stats;
2531
2532         if (tipc_link_is_active(l))
2533                 status = "ACTIVE";
2534         else if (tipc_link_is_up(l))
2535                 status = "STANDBY";
2536         else
2537                 status = "DEFUNCT";
2538
2539         ret = tipc_snprintf(buf, buf_size, "Link <%s>\n"
2540                             "  %s  MTU:%u  Priority:%u  Tolerance:%u ms"
2541                             "  Window:%u packets\n",
2542                             l->name, status, l->max_pkt, l->priority,
2543                             l->tolerance, l->queue_limit[0]);
2544
2545         ret += tipc_snprintf(buf + ret, buf_size - ret,
2546                              "  RX packets:%u fragments:%u/%u bundles:%u/%u\n",
2547                              l->next_in_no - s->recv_info, s->recv_fragments,
2548                              s->recv_fragmented, s->recv_bundles,
2549                              s->recv_bundled);
2550
2551         ret += tipc_snprintf(buf + ret, buf_size - ret,
2552                              "  TX packets:%u fragments:%u/%u bundles:%u/%u\n",
2553                              l->next_out_no - s->sent_info, s->sent_fragments,
2554                              s->sent_fragmented, s->sent_bundles,
2555                              s->sent_bundled);
2556
2557         profile_total = s->msg_length_counts;
2558         if (!profile_total)
2559                 profile_total = 1;
2560
2561         ret += tipc_snprintf(buf + ret, buf_size - ret,
2562                              "  TX profile sample:%u packets  average:%u octets\n"
2563                              "  0-64:%u%% -256:%u%% -1024:%u%% -4096:%u%% "
2564                              "-16384:%u%% -32768:%u%% -66000:%u%%\n",
2565                              s->msg_length_counts,
2566                              s->msg_lengths_total / profile_total,
2567                              percent(s->msg_length_profile[0], profile_total),
2568                              percent(s->msg_length_profile[1], profile_total),
2569                              percent(s->msg_length_profile[2], profile_total),
2570                              percent(s->msg_length_profile[3], profile_total),
2571                              percent(s->msg_length_profile[4], profile_total),
2572                              percent(s->msg_length_profile[5], profile_total),
2573                              percent(s->msg_length_profile[6], profile_total));
2574
2575         ret += tipc_snprintf(buf + ret, buf_size - ret,
2576                              "  RX states:%u probes:%u naks:%u defs:%u"
2577                              " dups:%u\n", s->recv_states, s->recv_probes,
2578                              s->recv_nacks, s->deferred_recv, s->duplicates);
2579
2580         ret += tipc_snprintf(buf + ret, buf_size - ret,
2581                              "  TX states:%u probes:%u naks:%u acks:%u"
2582                              " dups:%u\n", s->sent_states, s->sent_probes,
2583                              s->sent_nacks, s->sent_acks, s->retransmitted);
2584
2585         ret += tipc_snprintf(buf + ret, buf_size - ret,
2586                              "  Congestion link:%u  Send queue"
2587                              " max:%u avg:%u\n", s->link_congs,
2588                              s->max_queue_sz, s->queue_sz_counts ?
2589                              (s->accu_queue_sz / s->queue_sz_counts) : 0);
2590
2591         tipc_node_unlock(node);
2592         return ret;
2593 }
2594
2595 struct sk_buff *tipc_link_cmd_show_stats(const void *req_tlv_area, int req_tlv_space)
2596 {
2597         struct sk_buff *buf;
2598         struct tlv_desc *rep_tlv;
2599         int str_len;
2600         int pb_len;
2601         char *pb;
2602
2603         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_NAME))
2604                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2605
2606         buf = tipc_cfg_reply_alloc(TLV_SPACE(ULTRA_STRING_MAX_LEN));
2607         if (!buf)
2608                 return NULL;
2609
2610         rep_tlv = (struct tlv_desc *)buf->data;
2611         pb = TLV_DATA(rep_tlv);
2612         pb_len = ULTRA_STRING_MAX_LEN;
2613         str_len = tipc_link_stats((char *)TLV_DATA(req_tlv_area),
2614                                   pb, pb_len);
2615         if (!str_len) {
2616                 kfree_skb(buf);
2617                 return tipc_cfg_reply_error_string("link not found");
2618         }
2619         str_len += 1;   /* for "\0" */
2620         skb_put(buf, TLV_SPACE(str_len));
2621         TLV_SET(rep_tlv, TIPC_TLV_ULTRA_STRING, NULL, str_len);
2622
2623         return buf;
2624 }
2625
2626 /**
2627  * tipc_link_get_max_pkt - get maximum packet size to use when sending to destination
2628  * @dest: network address of destination node
2629  * @selector: used to select from set of active links
2630  *
2631  * If no active link can be found, uses default maximum packet size.
2632  */
2633 u32 tipc_link_get_max_pkt(u32 dest, u32 selector)
2634 {
2635         struct tipc_node *n_ptr;
2636         struct tipc_link *l_ptr;
2637         u32 res = MAX_PKT_DEFAULT;
2638
2639         if (dest == tipc_own_addr)
2640                 return MAX_MSG_SIZE;
2641
2642         n_ptr = tipc_node_find(dest);
2643         if (n_ptr) {
2644                 tipc_node_lock(n_ptr);
2645                 l_ptr = n_ptr->active_links[selector & 1];
2646                 if (l_ptr)
2647                         res = l_ptr->max_pkt;
2648                 tipc_node_unlock(n_ptr);
2649         }
2650         return res;
2651 }
2652
2653 static void link_print(struct tipc_link *l_ptr, const char *str)
2654 {
2655         struct tipc_bearer *b_ptr;
2656
2657         rcu_read_lock();
2658         b_ptr = rcu_dereference_rtnl(bearer_list[l_ptr->bearer_id]);
2659         if (b_ptr)
2660                 pr_info("%s Link %x<%s>:", str, l_ptr->addr, b_ptr->name);
2661         rcu_read_unlock();
2662
2663         if (link_working_unknown(l_ptr))
2664                 pr_cont(":WU\n");
2665         else if (link_reset_reset(l_ptr))
2666                 pr_cont(":RR\n");
2667         else if (link_reset_unknown(l_ptr))
2668                 pr_cont(":RU\n");
2669         else if (link_working_working(l_ptr))
2670                 pr_cont(":WW\n");
2671         else
2672                 pr_cont("\n");
2673 }