net/tipc/link.c

   1 /*
   2  * net/tipc/link.c: TIPC link code
   3  *
   4  * Copyright (c) 1996-2007, 2012, 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 "name_distr.h"
  41 #include "discover.h"
  42 #include "config.h"
  43
  44 #include <linux/pkt_sched.h>
  45
  46 /*
  47  * Error message prefixes
  48  */
  49 static const char *link_co_err = "Link changeover error, ";
  50 static const char *link_rst_msg = "Resetting link ";
  51 static const char *link_unk_evt = "Unknown link event ";
  52
  53 /*
  54  * Out-of-range value for link session numbers
  55  */
  56 #define INVALID_SESSION 0x10000
  57
  58 /*
  59  * Link state events:
  60  */
  61 #define  STARTING_EVT    856384768      /* link processing trigger */
  62 #define  TRAFFIC_MSG_EVT 560815u        /* rx'd ??? */
  63 #define  TIMEOUT_EVT     560817u        /* link timer expired */
  64
  65 /*
  66  * The following two 'message types' is really just implementation
  67  * data conveniently stored in the message header.
  68  * They must not be considered part of the protocol
  69  */
  70 #define OPEN_MSG   0
  71 #define CLOSED_MSG 1
  72
  73 /*
  74  * State value stored in 'exp_msg_count'
  75  */
  76 #define START_CHANGEOVER 100000u
  77
  78 static void link_handle_out_of_seq_msg(struct tipc_link *l_ptr,
  79                                        struct sk_buff *buf);
  80 static void link_recv_proto_msg(struct tipc_link *l_ptr, struct sk_buff *buf);
  81 static int  link_recv_changeover_msg(struct tipc_link **l_ptr,
  82                                      struct sk_buff **buf);
  83 static void link_set_supervision_props(struct tipc_link *l_ptr, u32 tolerance);
  84 static int  link_send_sections_long(struct tipc_port *sender,
  85                                     struct iovec const *msg_sect,
  86                                     unsigned int len, u32 destnode);
  87 static void link_state_event(struct tipc_link *l_ptr, u32 event);
  88 static void link_reset_statistics(struct tipc_link *l_ptr);
  89 static void link_print(struct tipc_link *l_ptr, const char *str);
  90 static void link_start(struct tipc_link *l_ptr);
  91 static int link_send_long_buf(struct tipc_link *l_ptr, struct sk_buff *buf);
  92 static void tipc_link_send_sync(struct tipc_link *l);
  93 static void tipc_link_recv_sync(struct tipc_node *n, struct sk_buff *buf);
  94
  95 /*
  96  *  Simple link routines
  97  */
  98 static unsigned int align(unsigned int i)
  99 {
 100         return (i + 3) & ~3u;
 101 }
 102
 103 static void link_init_max_pkt(struct tipc_link *l_ptr)
 104 {
 105         u32 max_pkt;
 106
 107         max_pkt = (l_ptr->b_ptr->mtu & ~3);
 108         if (max_pkt > MAX_MSG_SIZE)
 109                 max_pkt = MAX_MSG_SIZE;
 110
 111         l_ptr->max_pkt_target = max_pkt;
 112         if (l_ptr->max_pkt_target < MAX_PKT_DEFAULT)
 113                 l_ptr->max_pkt = l_ptr->max_pkt_target;
 114         else
 115                 l_ptr->max_pkt = MAX_PKT_DEFAULT;
 116
 117         l_ptr->max_pkt_probes = 0;
 118 }
 119
 120 static u32 link_next_sent(struct tipc_link *l_ptr)
 121 {
 122         if (l_ptr->next_out)
 123                 return buf_seqno(l_ptr->next_out);
 124         return mod(l_ptr->next_out_no);
 125 }
 126
 127 static u32 link_last_sent(struct tipc_link *l_ptr)
 128 {
 129         return mod(link_next_sent(l_ptr) - 1);
 130 }
 131
 132 /*
 133  *  Simple non-static link routines (i.e. referenced outside this file)
 134  */
 135 int tipc_link_is_up(struct tipc_link *l_ptr)
 136 {
 137         if (!l_ptr)
 138                 return 0;
 139         return link_working_working(l_ptr) || link_working_unknown(l_ptr);
 140 }
 141
 142 int tipc_link_is_active(struct tipc_link *l_ptr)
 143 {
 144         return  (l_ptr->owner->active_links[0] == l_ptr) ||
 145                 (l_ptr->owner->active_links[1] == l_ptr);
 146 }
 147
 148 /**
 149  * link_timeout - handle expiration of link timer
 150  * @l_ptr: pointer to link
 151  *
 152  * This routine must not grab "tipc_net_lock" to avoid a potential deadlock conflict
 153  * with tipc_link_delete().  (There is no risk that the node will be deleted by
 154  * another thread because tipc_link_delete() always cancels the link timer before
 155  * tipc_node_delete() is called.)
 156  */
 157 static void link_timeout(struct tipc_link *l_ptr)
 158 {
 159         tipc_node_lock(l_ptr->owner);
 160
 161         /* update counters used in statistical profiling of send traffic */
 162         l_ptr->stats.accu_queue_sz += l_ptr->out_queue_size;
 163         l_ptr->stats.queue_sz_counts++;
 164
 165         if (l_ptr->first_out) {
 166                 struct tipc_msg *msg = buf_msg(l_ptr->first_out);
 167                 u32 length = msg_size(msg);
 168
 169                 if ((msg_user(msg) == MSG_FRAGMENTER) &&
 170                     (msg_type(msg) == FIRST_FRAGMENT)) {
 171                         length = msg_size(msg_get_wrapped(msg));
 172                 }
 173                 if (length) {
 174                         l_ptr->stats.msg_lengths_total += length;
 175                         l_ptr->stats.msg_length_counts++;
 176                         if (length <= 64)
 177                                 l_ptr->stats.msg_length_profile[0]++;
 178                         else if (length <= 256)
 179                                 l_ptr->stats.msg_length_profile[1]++;
 180                         else if (length <= 1024)
 181                                 l_ptr->stats.msg_length_profile[2]++;
 182                         else if (length <= 4096)
 183                                 l_ptr->stats.msg_length_profile[3]++;
 184                         else if (length <= 16384)
 185                                 l_ptr->stats.msg_length_profile[4]++;
 186                         else if (length <= 32768)
 187                                 l_ptr->stats.msg_length_profile[5]++;
 188                         else
 189                                 l_ptr->stats.msg_length_profile[6]++;
 190                 }
 191         }
 192
 193         /* do all other link processing performed on a periodic basis */
 194
 195         link_state_event(l_ptr, TIMEOUT_EVT);
 196
 197         if (l_ptr->next_out)
 198                 tipc_link_push_queue(l_ptr);
 199
 200         tipc_node_unlock(l_ptr->owner);
 201 }
 202
 203 static void link_set_timer(struct tipc_link *l_ptr, u32 time)
 204 {
 205         k_start_timer(&l_ptr->timer, time);
 206 }
 207
 208 /**
 209  * tipc_link_create - create a new link
 210  * @n_ptr: pointer to associated node
 211  * @b_ptr: pointer to associated bearer
 212  * @media_addr: media address to use when sending messages over link
 213  *
 214  * Returns pointer to link.
 215  */
 216 struct tipc_link *tipc_link_create(struct tipc_node *n_ptr,
 217                               struct tipc_bearer *b_ptr,
 218                               const struct tipc_media_addr *media_addr)
 219 {
 220         struct tipc_link *l_ptr;
 221         struct tipc_msg *msg;
 222         char *if_name;
 223         char addr_string[16];
 224         u32 peer = n_ptr->addr;
 225
 226         if (n_ptr->link_cnt >= 2) {
 227                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 228                 pr_err("Attempt to establish third link to %s\n", addr_string);
 229                 return NULL;
 230         }
 231
 232         if (n_ptr->links[b_ptr->identity]) {
 233                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 234                 pr_err("Attempt to establish second link on <%s> to %s\n",
 235                        b_ptr->name, addr_string);
 236                 return NULL;
 237         }
 238
 239         l_ptr = kzalloc(sizeof(*l_ptr), GFP_ATOMIC);
 240         if (!l_ptr) {
 241                 pr_warn("Link creation failed, no memory\n");
 242                 return NULL;
 243         }
 244
 245         l_ptr->addr = peer;
 246         if_name = strchr(b_ptr->name, ':') + 1;
 247         sprintf(l_ptr->name, "%u.%u.%u:%s-%u.%u.%u:unknown",
 248                 tipc_zone(tipc_own_addr), tipc_cluster(tipc_own_addr),
 249                 tipc_node(tipc_own_addr),
 250                 if_name,
 251                 tipc_zone(peer), tipc_cluster(peer), tipc_node(peer));
 252                 /* note: peer i/f name is updated by reset/activate message */
 253         memcpy(&l_ptr->media_addr, media_addr, sizeof(*media_addr));
 254         l_ptr->owner = n_ptr;
 255         l_ptr->checkpoint = 1;
 256         l_ptr->peer_session = INVALID_SESSION;
 257         l_ptr->b_ptr = b_ptr;
 258         link_set_supervision_props(l_ptr, b_ptr->tolerance);
 259         l_ptr->state = RESET_UNKNOWN;
 260
 261         l_ptr->pmsg = (struct tipc_msg *)&l_ptr->proto_msg;
 262         msg = l_ptr->pmsg;
 263         tipc_msg_init(msg, LINK_PROTOCOL, RESET_MSG, INT_H_SIZE, l_ptr->addr);
 264         msg_set_size(msg, sizeof(l_ptr->proto_msg));
 265         msg_set_session(msg, (tipc_random & 0xffff));
 266         msg_set_bearer_id(msg, b_ptr->identity);
 267         strcpy((char *)msg_data(msg), if_name);
 268
 269         l_ptr->priority = b_ptr->priority;
 270         tipc_link_set_queue_limits(l_ptr, b_ptr->window);
 271
 272         link_init_max_pkt(l_ptr);
 273
 274         l_ptr->next_out_no = 1;
 275         INIT_LIST_HEAD(&l_ptr->waiting_ports);
 276
 277         link_reset_statistics(l_ptr);
 278
 279         tipc_node_attach_link(n_ptr, l_ptr);
 280
 281         k_init_timer(&l_ptr->timer, (Handler)link_timeout, (unsigned long)l_ptr);
 282         list_add_tail(&l_ptr->link_list, &b_ptr->links);
 283         tipc_k_signal((Handler)link_start, (unsigned long)l_ptr);
 284
 285         return l_ptr;
 286 }
 287
 288 /**
 289  * tipc_link_delete - delete a link
 290  * @l_ptr: pointer to link
 291  *
 292  * Note: 'tipc_net_lock' is write_locked, bearer is locked.
 293  * This routine must not grab the node lock until after link timer cancellation
 294  * to avoid a potential deadlock situation.
 295  */
 296 void tipc_link_delete(struct tipc_link *l_ptr)
 297 {
 298         if (!l_ptr) {
 299                 pr_err("Attempt to delete non-existent link\n");
 300                 return;
 301         }
 302
 303         k_cancel_timer(&l_ptr->timer);
 304
 305         tipc_node_lock(l_ptr->owner);
 306         tipc_link_reset(l_ptr);
 307         tipc_node_detach_link(l_ptr->owner, l_ptr);
 308         tipc_link_stop(l_ptr);
 309         list_del_init(&l_ptr->link_list);
 310         tipc_node_unlock(l_ptr->owner);
 311         k_term_timer(&l_ptr->timer);
 312         kfree(l_ptr);
 313 }
 314
 315 static void link_start(struct tipc_link *l_ptr)
 316 {
 317         tipc_node_lock(l_ptr->owner);
 318         link_state_event(l_ptr, STARTING_EVT);
 319         tipc_node_unlock(l_ptr->owner);
 320 }
 321
 322 /**
 323  * link_schedule_port - schedule port for deferred sending
 324  * @l_ptr: pointer to link
 325  * @origport: reference to sending port
 326  * @sz: amount of data to be sent
 327  *
 328  * Schedules port for renewed sending of messages after link congestion
 329  * has abated.
 330  */
 331 static int link_schedule_port(struct tipc_link *l_ptr, u32 origport, u32 sz)
 332 {
 333         struct tipc_port *p_ptr;
 334
 335         spin_lock_bh(&tipc_port_list_lock);
 336         p_ptr = tipc_port_lock(origport);
 337         if (p_ptr) {
 338                 if (!p_ptr->wakeup)
 339                         goto exit;
 340                 if (!list_empty(&p_ptr->wait_list))
 341                         goto exit;
 342                 p_ptr->congested = 1;
 343                 p_ptr->waiting_pkts = 1 + ((sz - 1) / l_ptr->max_pkt);
 344                 list_add_tail(&p_ptr->wait_list, &l_ptr->waiting_ports);
 345                 l_ptr->stats.link_congs++;
 346 exit:
 347                 tipc_port_unlock(p_ptr);
 348         }
 349         spin_unlock_bh(&tipc_port_list_lock);
 350         return -ELINKCONG;
 351 }
 352
 353 void tipc_link_wakeup_ports(struct tipc_link *l_ptr, int all)
 354 {
 355         struct tipc_port *p_ptr;
 356         struct tipc_port *temp_p_ptr;
 357         int win = l_ptr->queue_limit[0] - l_ptr->out_queue_size;
 358
 359         if (all)
 360                 win = 100000;
 361         if (win <= 0)
 362                 return;
 363         if (!spin_trylock_bh(&tipc_port_list_lock))
 364                 return;
 365         if (link_congested(l_ptr))
 366                 goto exit;
 367         list_for_each_entry_safe(p_ptr, temp_p_ptr, &l_ptr->waiting_ports,
 368                                  wait_list) {
 369                 if (win <= 0)
 370                         break;
 371                 list_del_init(&p_ptr->wait_list);
 372                 spin_lock_bh(p_ptr->lock);
 373                 p_ptr->congested = 0;
 374                 p_ptr->wakeup(p_ptr);
 375                 win -= p_ptr->waiting_pkts;
 376                 spin_unlock_bh(p_ptr->lock);
 377         }
 378
 379 exit:
 380         spin_unlock_bh(&tipc_port_list_lock);
 381 }
 382
 383 /**
 384  * link_release_outqueue - purge link's outbound message queue
 385  * @l_ptr: pointer to link
 386  */
 387 static void link_release_outqueue(struct tipc_link *l_ptr)
 388 {
 389         struct sk_buff *buf = l_ptr->first_out;
 390         struct sk_buff *next;
 391
 392         while (buf) {
 393                 next = buf->next;
 394                 kfree_skb(buf);
 395                 buf = next;
 396         }
 397         l_ptr->first_out = NULL;
 398         l_ptr->out_queue_size = 0;
 399 }
 400
 401 /**
 402  * tipc_link_reset_fragments - purge link's inbound message fragments queue
 403  * @l_ptr: pointer to link
 404  */
 405 void tipc_link_reset_fragments(struct tipc_link *l_ptr)
 406 {
 407         kfree_skb(l_ptr->reasm_head);
 408         l_ptr->reasm_head = NULL;
 409         l_ptr->reasm_tail = NULL;
 410 }
 411
 412 /**
 413  * tipc_link_stop - purge all inbound and outbound messages associated with link
 414  * @l_ptr: pointer to link
 415  */
 416 void tipc_link_stop(struct tipc_link *l_ptr)
 417 {
 418         struct sk_buff *buf;
 419         struct sk_buff *next;
 420
 421         buf = l_ptr->oldest_deferred_in;
 422         while (buf) {
 423                 next = buf->next;
 424                 kfree_skb(buf);
 425                 buf = next;
 426         }
 427
 428         buf = l_ptr->first_out;
 429         while (buf) {
 430                 next = buf->next;
 431                 kfree_skb(buf);
 432                 buf = next;
 433         }
 434
 435         tipc_link_reset_fragments(l_ptr);
 436
 437         kfree_skb(l_ptr->proto_msg_queue);
 438         l_ptr->proto_msg_queue = NULL;
 439 }
 440
 441 void tipc_link_reset(struct tipc_link *l_ptr)
 442 {
 443         struct sk_buff *buf;
 444         u32 prev_state = l_ptr->state;
 445         u32 checkpoint = l_ptr->next_in_no;
 446         int was_active_link = tipc_link_is_active(l_ptr);
 447
 448         msg_set_session(l_ptr->pmsg, ((msg_session(l_ptr->pmsg) + 1) & 0xffff));
 449
 450         /* Link is down, accept any session */
 451         l_ptr->peer_session = INVALID_SESSION;
 452
 453         /* Prepare for max packet size negotiation */
 454         link_init_max_pkt(l_ptr);
 455
 456         l_ptr->state = RESET_UNKNOWN;
 457
 458         if ((prev_state == RESET_UNKNOWN) || (prev_state == RESET_RESET))
 459                 return;
 460
 461         tipc_node_link_down(l_ptr->owner, l_ptr);
 462         tipc_bearer_remove_dest(l_ptr->b_ptr, l_ptr->addr);
 463
 464         if (was_active_link && tipc_node_active_links(l_ptr->owner) &&
 465             l_ptr->owner->permit_changeover) {
 466                 l_ptr->reset_checkpoint = checkpoint;
 467                 l_ptr->exp_msg_count = START_CHANGEOVER;
 468         }
 469
 470         /* Clean up all queues: */
 471         link_release_outqueue(l_ptr);
 472         kfree_skb(l_ptr->proto_msg_queue);
 473         l_ptr->proto_msg_queue = NULL;
 474         buf = l_ptr->oldest_deferred_in;
 475         while (buf) {
 476                 struct sk_buff *next = buf->next;
 477                 kfree_skb(buf);
 478                 buf = next;
 479         }
 480         if (!list_empty(&l_ptr->waiting_ports))
 481                 tipc_link_wakeup_ports(l_ptr, 1);
 482
 483         l_ptr->retransm_queue_head = 0;
 484         l_ptr->retransm_queue_size = 0;
 485         l_ptr->last_out = NULL;
 486         l_ptr->first_out = NULL;
 487         l_ptr->next_out = NULL;
 488         l_ptr->unacked_window = 0;
 489         l_ptr->checkpoint = 1;
 490         l_ptr->next_out_no = 1;
 491         l_ptr->deferred_inqueue_sz = 0;
 492         l_ptr->oldest_deferred_in = NULL;
 493         l_ptr->newest_deferred_in = NULL;
 494         l_ptr->fsm_msg_cnt = 0;
 495         l_ptr->stale_count = 0;
 496         link_reset_statistics(l_ptr);
 497 }
 498
 499
 500 static void link_activate(struct tipc_link *l_ptr)
 501 {
 502         l_ptr->next_in_no = l_ptr->stats.recv_info = 1;
 503         tipc_node_link_up(l_ptr->owner, l_ptr);
 504         tipc_bearer_add_dest(l_ptr->b_ptr, l_ptr->addr);
 505 }
 506
 507 /**
 508  * link_state_event - link finite state machine
 509  * @l_ptr: pointer to link
 510  * @event: state machine event to process
 511  */
 512 static void link_state_event(struct tipc_link *l_ptr, unsigned int event)
 513 {
 514         struct tipc_link *other;
 515         u32 cont_intv = l_ptr->continuity_interval;
 516
 517         if (!l_ptr->started && (event != STARTING_EVT))
 518                 return;         /* Not yet. */
 519
 520         if (link_blocked(l_ptr)) {
 521                 if (event == TIMEOUT_EVT)
 522                         link_set_timer(l_ptr, cont_intv);
 523                 return;   /* Changeover going on */
 524         }
 525
 526         switch (l_ptr->state) {
 527         case WORKING_WORKING:
 528                 switch (event) {
 529                 case TRAFFIC_MSG_EVT:
 530                 case ACTIVATE_MSG:
 531                         break;
 532                 case TIMEOUT_EVT:
 533                         if (l_ptr->next_in_no != l_ptr->checkpoint) {
 534                                 l_ptr->checkpoint = l_ptr->next_in_no;
 535                                 if (tipc_bclink_acks_missing(l_ptr->owner)) {
 536                                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
 537                                                                  0, 0, 0, 0, 0);
 538                                         l_ptr->fsm_msg_cnt++;
 539                                 } else if (l_ptr->max_pkt < l_ptr->max_pkt_target) {
 540                                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
 541                                                                  1, 0, 0, 0, 0);
 542                                         l_ptr->fsm_msg_cnt++;
 543                                 }
 544                                 link_set_timer(l_ptr, cont_intv);
 545                                 break;
 546                         }
 547                         l_ptr->state = WORKING_UNKNOWN;
 548                         l_ptr->fsm_msg_cnt = 0;
 549                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
 550                         l_ptr->fsm_msg_cnt++;
 551                         link_set_timer(l_ptr, cont_intv / 4);
 552                         break;
 553                 case RESET_MSG:
 554                         pr_info("%s<%s>, requested by peer\n", link_rst_msg,
 555                                 l_ptr->name);
 556                         tipc_link_reset(l_ptr);
 557                         l_ptr->state = RESET_RESET;
 558                         l_ptr->fsm_msg_cnt = 0;
 559                         tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
 560                         l_ptr->fsm_msg_cnt++;
 561                         link_set_timer(l_ptr, cont_intv);
 562                         break;
 563                 default:
 564                         pr_err("%s%u in WW state\n", link_unk_evt, event);
 565                 }
 566                 break;
 567         case WORKING_UNKNOWN:
 568                 switch (event) {
 569                 case TRAFFIC_MSG_EVT:
 570                 case ACTIVATE_MSG:
 571                         l_ptr->state = WORKING_WORKING;
 572                         l_ptr->fsm_msg_cnt = 0;
 573                         link_set_timer(l_ptr, cont_intv);
 574                         break;
 575                 case RESET_MSG:
 576                         pr_info("%s<%s>, requested by peer while probing\n",
 577                                 link_rst_msg, l_ptr->name);
 578                         tipc_link_reset(l_ptr);
 579                         l_ptr->state = RESET_RESET;
 580                         l_ptr->fsm_msg_cnt = 0;
 581                         tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
 582                         l_ptr->fsm_msg_cnt++;
 583                         link_set_timer(l_ptr, cont_intv);
 584                         break;
 585                 case TIMEOUT_EVT:
 586                         if (l_ptr->next_in_no != l_ptr->checkpoint) {
 587                                 l_ptr->state = WORKING_WORKING;
 588                                 l_ptr->fsm_msg_cnt = 0;
 589                                 l_ptr->checkpoint = l_ptr->next_in_no;
 590                                 if (tipc_bclink_acks_missing(l_ptr->owner)) {
 591                                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
 592                                                                  0, 0, 0, 0, 0);
 593                                         l_ptr->fsm_msg_cnt++;
 594                                 }
 595                                 link_set_timer(l_ptr, cont_intv);
 596                         } else if (l_ptr->fsm_msg_cnt < l_ptr->abort_limit) {
 597                                 tipc_link_send_proto_msg(l_ptr, STATE_MSG,
 598                                                          1, 0, 0, 0, 0);
 599                                 l_ptr->fsm_msg_cnt++;
 600                                 link_set_timer(l_ptr, cont_intv / 4);
 601                         } else {        /* Link has failed */
 602                                 pr_warn("%s<%s>, peer not responding\n",
 603                                         link_rst_msg, l_ptr->name);
 604                                 tipc_link_reset(l_ptr);
 605                                 l_ptr->state = RESET_UNKNOWN;
 606                                 l_ptr->fsm_msg_cnt = 0;
 607                                 tipc_link_send_proto_msg(l_ptr, RESET_MSG,
 608                                                          0, 0, 0, 0, 0);
 609                                 l_ptr->fsm_msg_cnt++;
 610                                 link_set_timer(l_ptr, cont_intv);
 611                         }
 612                         break;
 613                 default:
 614                         pr_err("%s%u in WU state\n", link_unk_evt, event);
 615                 }
 616                 break;
 617         case RESET_UNKNOWN:
 618                 switch (event) {
 619                 case TRAFFIC_MSG_EVT:
 620                         break;
 621                 case ACTIVATE_MSG:
 622                         other = l_ptr->owner->active_links[0];
 623                         if (other && link_working_unknown(other))
 624                                 break;
 625                         l_ptr->state = WORKING_WORKING;
 626                         l_ptr->fsm_msg_cnt = 0;
 627                         link_activate(l_ptr);
 628                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
 629                         l_ptr->fsm_msg_cnt++;
 630                         if (l_ptr->owner->working_links == 1)
 631                                 tipc_link_send_sync(l_ptr);
 632                         link_set_timer(l_ptr, cont_intv);
 633                         break;
 634                 case RESET_MSG:
 635                         l_ptr->state = RESET_RESET;
 636                         l_ptr->fsm_msg_cnt = 0;
 637                         tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 1, 0, 0, 0, 0);
 638                         l_ptr->fsm_msg_cnt++;
 639                         link_set_timer(l_ptr, cont_intv);
 640                         break;
 641                 case STARTING_EVT:
 642                         l_ptr->started = 1;
 643                         /* fall through */
 644                 case TIMEOUT_EVT:
 645                         tipc_link_send_proto_msg(l_ptr, RESET_MSG, 0, 0, 0, 0, 0);
 646                         l_ptr->fsm_msg_cnt++;
 647                         link_set_timer(l_ptr, cont_intv);
 648                         break;
 649                 default:
 650                         pr_err("%s%u in RU state\n", link_unk_evt, event);
 651                 }
 652                 break;
 653         case RESET_RESET:
 654                 switch (event) {
 655                 case TRAFFIC_MSG_EVT:
 656                 case ACTIVATE_MSG:
 657                         other = l_ptr->owner->active_links[0];
 658                         if (other && link_working_unknown(other))
 659                                 break;
 660                         l_ptr->state = WORKING_WORKING;
 661                         l_ptr->fsm_msg_cnt = 0;
 662                         link_activate(l_ptr);
 663                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
 664                         l_ptr->fsm_msg_cnt++;
 665                         if (l_ptr->owner->working_links == 1)
 666                                 tipc_link_send_sync(l_ptr);
 667                         link_set_timer(l_ptr, cont_intv);
 668                         break;
 669                 case RESET_MSG:
 670                         break;
 671                 case TIMEOUT_EVT:
 672                         tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
 673                         l_ptr->fsm_msg_cnt++;
 674                         link_set_timer(l_ptr, cont_intv);
 675                         break;
 676                 default:
 677                         pr_err("%s%u in RR state\n", link_unk_evt, event);
 678                 }
 679                 break;
 680         default:
 681                 pr_err("Unknown link state %u/%u\n", l_ptr->state, event);
 682         }
 683 }
 684
 685 /*
 686  * link_bundle_buf(): Append contents of a buffer to
 687  * the tail of an existing one.
 688  */
 689 static int link_bundle_buf(struct tipc_link *l_ptr, struct sk_buff *bundler,
 690                            struct sk_buff *buf)
 691 {
 692         struct tipc_msg *bundler_msg = buf_msg(bundler);
 693         struct tipc_msg *msg = buf_msg(buf);
 694         u32 size = msg_size(msg);
 695         u32 bundle_size = msg_size(bundler_msg);
 696         u32 to_pos = align(bundle_size);
 697         u32 pad = to_pos - bundle_size;
 698
 699         if (msg_user(bundler_msg) != MSG_BUNDLER)
 700                 return 0;
 701         if (msg_type(bundler_msg) != OPEN_MSG)
 702                 return 0;
 703         if (skb_tailroom(bundler) < (pad + size))
 704                 return 0;
 705         if (l_ptr->max_pkt < (to_pos + size))
 706                 return 0;
 707
 708         skb_put(bundler, pad + size);
 709         skb_copy_to_linear_data_offset(bundler, to_pos, buf->data, size);
 710         msg_set_size(bundler_msg, to_pos + size);
 711         msg_set_msgcnt(bundler_msg, msg_msgcnt(bundler_msg) + 1);
 712         kfree_skb(buf);
 713         l_ptr->stats.sent_bundled++;
 714         return 1;
 715 }
 716
 717 static void link_add_to_outqueue(struct tipc_link *l_ptr,
 718                                  struct sk_buff *buf,
 719                                  struct tipc_msg *msg)
 720 {
 721         u32 ack = mod(l_ptr->next_in_no - 1);
 722         u32 seqno = mod(l_ptr->next_out_no++);
 723
 724         msg_set_word(msg, 2, ((ack << 16) | seqno));
 725         msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
 726         buf->next = NULL;
 727         if (l_ptr->first_out) {
 728                 l_ptr->last_out->next = buf;
 729                 l_ptr->last_out = buf;
 730         } else
 731                 l_ptr->first_out = l_ptr->last_out = buf;
 732
 733         l_ptr->out_queue_size++;
 734         if (l_ptr->out_queue_size > l_ptr->stats.max_queue_sz)
 735                 l_ptr->stats.max_queue_sz = l_ptr->out_queue_size;
 736 }
 737
 738 static void link_add_chain_to_outqueue(struct tipc_link *l_ptr,
 739                                        struct sk_buff *buf_chain,
 740                                        u32 long_msgno)
 741 {
 742         struct sk_buff *buf;
 743         struct tipc_msg *msg;
 744
 745         if (!l_ptr->next_out)
 746                 l_ptr->next_out = buf_chain;
 747         while (buf_chain) {
 748                 buf = buf_chain;
 749                 buf_chain = buf_chain->next;
 750
 751                 msg = buf_msg(buf);
 752                 msg_set_long_msgno(msg, long_msgno);
 753                 link_add_to_outqueue(l_ptr, buf, msg);
 754         }
 755 }
 756
 757 /*
 758  * tipc_link_send_buf() is the 'full path' for messages, called from
 759  * inside TIPC when the 'fast path' in tipc_send_buf
 760  * has failed, and from link_send()
 761  */
 762 int tipc_link_send_buf(struct tipc_link *l_ptr, struct sk_buff *buf)
 763 {
 764         struct tipc_msg *msg = buf_msg(buf);
 765         u32 size = msg_size(msg);
 766         u32 dsz = msg_data_sz(msg);
 767         u32 queue_size = l_ptr->out_queue_size;
 768         u32 imp = tipc_msg_tot_importance(msg);
 769         u32 queue_limit = l_ptr->queue_limit[imp];
 770         u32 max_packet = l_ptr->max_pkt;
 771
 772         /* Match msg importance against queue limits: */
 773         if (unlikely(queue_size >= queue_limit)) {
 774                 if (imp <= TIPC_CRITICAL_IMPORTANCE) {
 775                         link_schedule_port(l_ptr, msg_origport(msg), size);
 776                         kfree_skb(buf);
 777                         return -ELINKCONG;
 778                 }
 779                 kfree_skb(buf);
 780                 if (imp > CONN_MANAGER) {
 781                         pr_warn("%s<%s>, send queue full", link_rst_msg,
 782                                 l_ptr->name);
 783                         tipc_link_reset(l_ptr);
 784                 }
 785                 return dsz;
 786         }
 787
 788         /* Fragmentation needed ? */
 789         if (size > max_packet)
 790                 return link_send_long_buf(l_ptr, buf);
 791
 792         /* Packet can be queued or sent. */
 793         if (likely(!tipc_bearer_blocked(l_ptr->b_ptr) &&
 794                    !link_congested(l_ptr))) {
 795                 link_add_to_outqueue(l_ptr, buf, msg);
 796
 797                 tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr);
 798                 l_ptr->unacked_window = 0;
 799                 return dsz;
 800         }
 801         /* Congestion: can message be bundled ? */
 802         if ((msg_user(msg) != CHANGEOVER_PROTOCOL) &&
 803             (msg_user(msg) != MSG_FRAGMENTER)) {
 804
 805                 /* Try adding message to an existing bundle */
 806                 if (l_ptr->next_out &&
 807                     link_bundle_buf(l_ptr, l_ptr->last_out, buf))
 808                         return dsz;
 809
 810                 /* Try creating a new bundle */
 811                 if (size <= max_packet * 2 / 3) {
 812                         struct sk_buff *bundler = tipc_buf_acquire(max_packet);
 813                         struct tipc_msg bundler_hdr;
 814
 815                         if (bundler) {
 816                                 tipc_msg_init(&bundler_hdr, MSG_BUNDLER, OPEN_MSG,
 817                                          INT_H_SIZE, l_ptr->addr);
 818                                 skb_copy_to_linear_data(bundler, &bundler_hdr,
 819                                                         INT_H_SIZE);
 820                                 skb_trim(bundler, INT_H_SIZE);
 821                                 link_bundle_buf(l_ptr, bundler, buf);
 822                                 buf = bundler;
 823                                 msg = buf_msg(buf);
 824                                 l_ptr->stats.sent_bundles++;
 825                         }
 826                 }
 827         }
 828         if (!l_ptr->next_out)
 829                 l_ptr->next_out = buf;
 830         link_add_to_outqueue(l_ptr, buf, msg);
 831         return dsz;
 832 }
 833
 834 /*
 835  * tipc_link_send(): same as tipc_link_send_buf(), but the link to use has
 836  * not been selected yet, and the the owner node is not locked
 837  * Called by TIPC internal users, e.g. the name distributor
 838  */
 839 int tipc_link_send(struct sk_buff *buf, u32 dest, u32 selector)
 840 {
 841         struct tipc_link *l_ptr;
 842         struct tipc_node *n_ptr;
 843         int res = -ELINKCONG;
 844
 845         read_lock_bh(&tipc_net_lock);
 846         n_ptr = tipc_node_find(dest);
 847         if (n_ptr) {
 848                 tipc_node_lock(n_ptr);
 849                 l_ptr = n_ptr->active_links[selector & 1];
 850                 if (l_ptr)
 851                         res = tipc_link_send_buf(l_ptr, buf);
 852                 else
 853                         kfree_skb(buf);
 854                 tipc_node_unlock(n_ptr);
 855         } else {
 856                 kfree_skb(buf);
 857         }
 858         read_unlock_bh(&tipc_net_lock);
 859         return res;
 860 }
 861
 862 /*
 863  * tipc_link_send_sync - synchronize broadcast link endpoints.
 864  *
 865  * Give a newly added peer node the sequence number where it should
 866  * start receiving and acking broadcast packets.
 867  *
 868  * Called with node locked
 869  */
 870 static void tipc_link_send_sync(struct tipc_link *l)
 871 {
 872         struct sk_buff *buf;
 873         struct tipc_msg *msg;
 874
 875         buf = tipc_buf_acquire(INT_H_SIZE);
 876         if (!buf)
 877                 return;
 878
 879         msg = buf_msg(buf);
 880         tipc_msg_init(msg, BCAST_PROTOCOL, STATE_MSG, INT_H_SIZE, l->addr);
 881         msg_set_last_bcast(msg, l->owner->bclink.acked);
 882         link_add_chain_to_outqueue(l, buf, 0);
 883         tipc_link_push_queue(l);
 884 }
 885
 886 /*
 887  * tipc_link_recv_sync - synchronize broadcast link endpoints.
 888  * Receive the sequence number where we should start receiving and
 889  * acking broadcast packets from a newly added peer node, and open
 890  * up for reception of such packets.
 891  *
 892  * Called with node locked
 893  */
 894 static void tipc_link_recv_sync(struct tipc_node *n, struct sk_buff *buf)
 895 {
 896         struct tipc_msg *msg = buf_msg(buf);
 897
 898         n->bclink.last_sent = n->bclink.last_in = msg_last_bcast(msg);
 899         n->bclink.recv_permitted = true;
 900         kfree_skb(buf);
 901 }
 902
 903 /*
 904  * tipc_link_send_names - send name table entries to new neighbor
 905  *
 906  * Send routine for bulk delivery of name table messages when contact
 907  * with a new neighbor occurs. No link congestion checking is performed
 908  * because name table messages *must* be delivered. The messages must be
 909  * small enough not to require fragmentation.
 910  * Called without any locks held.
 911  */
 912 void tipc_link_send_names(struct list_head *message_list, u32 dest)
 913 {
 914         struct tipc_node *n_ptr;
 915         struct tipc_link *l_ptr;
 916         struct sk_buff *buf;
 917         struct sk_buff *temp_buf;
 918
 919         if (list_empty(message_list))
 920                 return;
 921
 922         read_lock_bh(&tipc_net_lock);
 923         n_ptr = tipc_node_find(dest);
 924         if (n_ptr) {
 925                 tipc_node_lock(n_ptr);
 926                 l_ptr = n_ptr->active_links[0];
 927                 if (l_ptr) {
 928                         /* convert circular list to linear list */
 929                         ((struct sk_buff *)message_list->prev)->next = NULL;
 930                         link_add_chain_to_outqueue(l_ptr,
 931                                 (struct sk_buff *)message_list->next, 0);
 932                         tipc_link_push_queue(l_ptr);
 933                         INIT_LIST_HEAD(message_list);
 934                 }
 935                 tipc_node_unlock(n_ptr);
 936         }
 937         read_unlock_bh(&tipc_net_lock);
 938
 939         /* discard the messages if they couldn't be sent */
 940         list_for_each_safe(buf, temp_buf, ((struct sk_buff *)message_list)) {
 941                 list_del((struct list_head *)buf);
 942                 kfree_skb(buf);
 943         }
 944 }
 945
 946 /*
 947  * link_send_buf_fast: Entry for data messages where the
 948  * destination link is known and the header is complete,
 949  * inclusive total message length. Very time critical.
 950  * Link is locked. Returns user data length.
 951  */
 952 static int link_send_buf_fast(struct tipc_link *l_ptr, struct sk_buff *buf,
 953                               u32 *used_max_pkt)
 954 {
 955         struct tipc_msg *msg = buf_msg(buf);
 956         int res = msg_data_sz(msg);
 957
 958         if (likely(!link_congested(l_ptr))) {
 959                 if (likely(msg_size(msg) <= l_ptr->max_pkt)) {
 960                         if (likely(!tipc_bearer_blocked(l_ptr->b_ptr))) {
 961                                 link_add_to_outqueue(l_ptr, buf, msg);
 962                                 tipc_bearer_send(l_ptr->b_ptr, buf,
 963                                                  &l_ptr->media_addr);
 964                                 l_ptr->unacked_window = 0;
 965                                 return res;
 966                         }
 967                 } else
 968                         *used_max_pkt = l_ptr->max_pkt;
 969         }
 970         return tipc_link_send_buf(l_ptr, buf);  /* All other cases */
 971 }
 972
 973 /*
 974  * tipc_link_send_sections_fast: Entry for messages where the
 975  * destination processor is known and the header is complete,
 976  * except for total message length.
 977  * Returns user data length or errno.
 978  */
 979 int tipc_link_send_sections_fast(struct tipc_port *sender,
 980                                  struct iovec const *msg_sect,
 981                                  unsigned int len, u32 destaddr)
 982 {
 983         struct tipc_msg *hdr = &sender->phdr;
 984         struct tipc_link *l_ptr;
 985         struct sk_buff *buf;
 986         struct tipc_node *node;
 987         int res;
 988         u32 selector = msg_origport(hdr) & 1;
 989
 990 again:
 991         /*
 992          * Try building message using port's max_pkt hint.
 993          * (Must not hold any locks while building message.)
 994          */
 995         res = tipc_msg_build(hdr, msg_sect, len, sender->max_pkt, &buf);
 996         /* Exit if build request was invalid */
 997         if (unlikely(res < 0))
 998                 return res;
 999
1000         read_lock_bh(&tipc_net_lock);
1001         node = tipc_node_find(destaddr);
1002         if (likely(node)) {
1003                 tipc_node_lock(node);
1004                 l_ptr = node->active_links[selector];
1005                 if (likely(l_ptr)) {
1006                         if (likely(buf)) {
1007                                 res = link_send_buf_fast(l_ptr, buf,
1008                                                          &sender->max_pkt);
1009 exit:
1010                                 tipc_node_unlock(node);
1011                                 read_unlock_bh(&tipc_net_lock);
1012                                 return res;
1013                         }
1014
1015                         /* Exit if link (or bearer) is congested */
1016                         if (link_congested(l_ptr) ||
1017                             tipc_bearer_blocked(l_ptr->b_ptr)) {
1018                                 res = link_schedule_port(l_ptr,
1019                                                          sender->ref, res);
1020                                 goto exit;
1021                         }
1022
1023                         /*
1024                          * Message size exceeds max_pkt hint; update hint,
1025                          * then re-try fast path or fragment the message
1026                          */
1027                         sender->max_pkt = l_ptr->max_pkt;
1028                         tipc_node_unlock(node);
1029                         read_unlock_bh(&tipc_net_lock);
1030
1031
1032                         if ((msg_hdr_sz(hdr) + res) <= sender->max_pkt)
1033                                 goto again;
1034
1035                         return link_send_sections_long(sender, msg_sect, len,
1036                                                        destaddr);
1037                 }
1038                 tipc_node_unlock(node);
1039         }
1040         read_unlock_bh(&tipc_net_lock);
1041
1042         /* Couldn't find a link to the destination node */
1043         if (buf)
1044                 return tipc_reject_msg(buf, TIPC_ERR_NO_NODE);
1045         if (res >= 0)
1046                 return tipc_port_reject_sections(sender, hdr, msg_sect,
1047                                                  len, TIPC_ERR_NO_NODE);
1048         return res;
1049 }
1050
1051 /*
1052  * link_send_sections_long(): Entry for long messages where the
1053  * destination node is known and the header is complete,
1054  * inclusive total message length.
1055  * Link and bearer congestion status have been checked to be ok,
1056  * and are ignored if they change.
1057  *
1058  * Note that fragments do not use the full link MTU so that they won't have
1059  * to undergo refragmentation if link changeover causes them to be sent
1060  * over another link with an additional tunnel header added as prefix.
1061  * (Refragmentation will still occur if the other link has a smaller MTU.)
1062  *
1063  * Returns user data length or errno.
1064  */
1065 static int link_send_sections_long(struct tipc_port *sender,
1066                                    struct iovec const *msg_sect,
1067                                    unsigned int len, u32 destaddr)
1068 {
1069         struct tipc_link *l_ptr;
1070         struct tipc_node *node;
1071         struct tipc_msg *hdr = &sender->phdr;
1072         u32 dsz = len;
1073         u32 max_pkt, fragm_sz, rest;
1074         struct tipc_msg fragm_hdr;
1075         struct sk_buff *buf, *buf_chain, *prev;
1076         u32 fragm_crs, fragm_rest, hsz, sect_rest;
1077         const unchar __user *sect_crs;
1078         int curr_sect;
1079         u32 fragm_no;
1080         int res = 0;
1081
1082 again:
1083         fragm_no = 1;
1084         max_pkt = sender->max_pkt - INT_H_SIZE;
1085                 /* leave room for tunnel header in case of link changeover */
1086         fragm_sz = max_pkt - INT_H_SIZE;
1087                 /* leave room for fragmentation header in each fragment */
1088         rest = dsz;
1089         fragm_crs = 0;
1090         fragm_rest = 0;
1091         sect_rest = 0;
1092         sect_crs = NULL;
1093         curr_sect = -1;
1094
1095         /* Prepare reusable fragment header */
1096         tipc_msg_init(&fragm_hdr, MSG_FRAGMENTER, FIRST_FRAGMENT,
1097                  INT_H_SIZE, msg_destnode(hdr));
1098         msg_set_size(&fragm_hdr, max_pkt);
1099         msg_set_fragm_no(&fragm_hdr, 1);
1100
1101         /* Prepare header of first fragment */
1102         buf_chain = buf = tipc_buf_acquire(max_pkt);
1103         if (!buf)
1104                 return -ENOMEM;
1105         buf->next = NULL;
1106         skb_copy_to_linear_data(buf, &fragm_hdr, INT_H_SIZE);
1107         hsz = msg_hdr_sz(hdr);
1108         skb_copy_to_linear_data_offset(buf, INT_H_SIZE, hdr, hsz);
1109
1110         /* Chop up message */
1111         fragm_crs = INT_H_SIZE + hsz;
1112         fragm_rest = fragm_sz - hsz;
1113
1114         do {            /* For all sections */
1115                 u32 sz;
1116
1117                 if (!sect_rest) {
1118                         sect_rest = msg_sect[++curr_sect].iov_len;
1119                         sect_crs = msg_sect[curr_sect].iov_base;
1120                 }
1121
1122                 if (sect_rest < fragm_rest)
1123                         sz = sect_rest;
1124                 else
1125                         sz = fragm_rest;
1126
1127                 if (copy_from_user(buf->data + fragm_crs, sect_crs, sz)) {
1128                         res = -EFAULT;
1129 error:
1130                         for (; buf_chain; buf_chain = buf) {
1131                                 buf = buf_chain->next;
1132                                 kfree_skb(buf_chain);
1133                         }
1134                         return res;
1135                 }
1136                 sect_crs += sz;
1137                 sect_rest -= sz;
1138                 fragm_crs += sz;
1139                 fragm_rest -= sz;
1140                 rest -= sz;
1141
1142                 if (!fragm_rest && rest) {
1143
1144                         /* Initiate new fragment: */
1145                         if (rest <= fragm_sz) {
1146                                 fragm_sz = rest;
1147                                 msg_set_type(&fragm_hdr, LAST_FRAGMENT);
1148                         } else {
1149                                 msg_set_type(&fragm_hdr, FRAGMENT);
1150                         }
1151                         msg_set_size(&fragm_hdr, fragm_sz + INT_H_SIZE);
1152                         msg_set_fragm_no(&fragm_hdr, ++fragm_no);
1153                         prev = buf;
1154                         buf = tipc_buf_acquire(fragm_sz + INT_H_SIZE);
1155                         if (!buf) {
1156                                 res = -ENOMEM;
1157                                 goto error;
1158                         }
1159
1160                         buf->next = NULL;
1161                         prev->next = buf;
1162                         skb_copy_to_linear_data(buf, &fragm_hdr, INT_H_SIZE);
1163                         fragm_crs = INT_H_SIZE;
1164                         fragm_rest = fragm_sz;
1165                 }
1166         } while (rest > 0);
1167
1168         /*
1169          * Now we have a buffer chain. Select a link and check
1170          * that packet size is still OK
1171          */
1172         node = tipc_node_find(destaddr);
1173         if (likely(node)) {
1174                 tipc_node_lock(node);
1175                 l_ptr = node->active_links[sender->ref & 1];
1176                 if (!l_ptr) {
1177                         tipc_node_unlock(node);
1178                         goto reject;
1179                 }
1180                 if (l_ptr->max_pkt < max_pkt) {
1181                         sender->max_pkt = l_ptr->max_pkt;
1182                         tipc_node_unlock(node);
1183                         for (; buf_chain; buf_chain = buf) {
1184                                 buf = buf_chain->next;
1185                                 kfree_skb(buf_chain);
1186                         }
1187                         goto again;
1188                 }
1189         } else {
1190 reject:
1191                 for (; buf_chain; buf_chain = buf) {
1192                         buf = buf_chain->next;
1193                         kfree_skb(buf_chain);
1194                 }
1195                 return tipc_port_reject_sections(sender, hdr, msg_sect,
1196                                                  len, TIPC_ERR_NO_NODE);
1197         }
1198
1199         /* Append chain of fragments to send queue & send them */
1200         l_ptr->long_msg_seq_no++;
1201         link_add_chain_to_outqueue(l_ptr, buf_chain, l_ptr->long_msg_seq_no);
1202         l_ptr->stats.sent_fragments += fragm_no;
1203         l_ptr->stats.sent_fragmented++;
1204         tipc_link_push_queue(l_ptr);
1205         tipc_node_unlock(node);
1206         return dsz;
1207 }
1208
1209 /*
1210  * tipc_link_push_packet: Push one unsent packet to the media
1211  */
1212 u32 tipc_link_push_packet(struct tipc_link *l_ptr)
1213 {
1214         struct sk_buff *buf = l_ptr->first_out;
1215         u32 r_q_size = l_ptr->retransm_queue_size;
1216         u32 r_q_head = l_ptr->retransm_queue_head;
1217
1218         /* Step to position where retransmission failed, if any,    */
1219         /* consider that buffers may have been released in meantime */
1220         if (r_q_size && buf) {
1221                 u32 last = lesser(mod(r_q_head + r_q_size),
1222                                   link_last_sent(l_ptr));
1223                 u32 first = buf_seqno(buf);
1224
1225                 while (buf && less(first, r_q_head)) {
1226                         first = mod(first + 1);
1227                         buf = buf->next;
1228                 }
1229                 l_ptr->retransm_queue_head = r_q_head = first;
1230                 l_ptr->retransm_queue_size = r_q_size = mod(last - first);
1231         }
1232
1233         /* Continue retransmission now, if there is anything: */
1234         if (r_q_size && buf) {
1235                 msg_set_ack(buf_msg(buf), mod(l_ptr->next_in_no - 1));
1236                 msg_set_bcast_ack(buf_msg(buf), l_ptr->owner->bclink.last_in);
1237                 tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr);
1238                 l_ptr->retransm_queue_head = mod(++r_q_head);
1239                 l_ptr->retransm_queue_size = --r_q_size;
1240                 l_ptr->stats.retransmitted++;
1241                 return 0;
1242         }
1243
1244         /* Send deferred protocol message, if any: */
1245         buf = l_ptr->proto_msg_queue;
1246         if (buf) {
1247                 msg_set_ack(buf_msg(buf), mod(l_ptr->next_in_no - 1));
1248                 msg_set_bcast_ack(buf_msg(buf), l_ptr->owner->bclink.last_in);
1249                 tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr);
1250                 l_ptr->unacked_window = 0;
1251                 kfree_skb(buf);
1252                 l_ptr->proto_msg_queue = NULL;
1253                 return 0;
1254         }
1255
1256         /* Send one deferred data message, if send window not full: */
1257         buf = l_ptr->next_out;
1258         if (buf) {
1259                 struct tipc_msg *msg = buf_msg(buf);
1260                 u32 next = msg_seqno(msg);
1261                 u32 first = buf_seqno(l_ptr->first_out);
1262
1263                 if (mod(next - first) < l_ptr->queue_limit[0]) {
1264                         msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1265                         msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1266                         tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr);
1267                         if (msg_user(msg) == MSG_BUNDLER)
1268                                 msg_set_type(msg, CLOSED_MSG);
1269                         l_ptr->next_out = buf->next;
1270                         return 0;
1271                 }
1272         }
1273         return 1;
1274 }
1275
1276 /*
1277  * push_queue(): push out the unsent messages of a link where
1278  *               congestion has abated. Node is locked
1279  */
1280 void tipc_link_push_queue(struct tipc_link *l_ptr)
1281 {
1282         u32 res;
1283
1284         if (tipc_bearer_blocked(l_ptr->b_ptr))
1285                 return;
1286
1287         do {
1288                 res = tipc_link_push_packet(l_ptr);
1289         } while (!res);
1290 }
1291
1292 static void link_reset_all(unsigned long addr)
1293 {
1294         struct tipc_node *n_ptr;
1295         char addr_string[16];
1296         u32 i;
1297
1298         read_lock_bh(&tipc_net_lock);
1299         n_ptr = tipc_node_find((u32)addr);
1300         if (!n_ptr) {
1301                 read_unlock_bh(&tipc_net_lock);
1302                 return; /* node no longer exists */
1303         }
1304
1305         tipc_node_lock(n_ptr);
1306
1307         pr_warn("Resetting all links to %s\n",
1308                 tipc_addr_string_fill(addr_string, n_ptr->addr));
1309
1310         for (i = 0; i < MAX_BEARERS; i++) {
1311                 if (n_ptr->links[i]) {
1312                         link_print(n_ptr->links[i], "Resetting link\n");
1313                         tipc_link_reset(n_ptr->links[i]);
1314                 }
1315         }
1316
1317         tipc_node_unlock(n_ptr);
1318         read_unlock_bh(&tipc_net_lock);
1319 }
1320
1321 static void link_retransmit_failure(struct tipc_link *l_ptr,
1322                                     struct sk_buff *buf)
1323 {
1324         struct tipc_msg *msg = buf_msg(buf);
1325
1326         pr_warn("Retransmission failure on link <%s>\n", l_ptr->name);
1327
1328         if (l_ptr->addr) {
1329                 /* Handle failure on standard link */
1330                 link_print(l_ptr, "Resetting link\n");
1331                 tipc_link_reset(l_ptr);
1332
1333         } else {
1334                 /* Handle failure on broadcast link */
1335                 struct tipc_node *n_ptr;
1336                 char addr_string[16];
1337
1338                 pr_info("Msg seq number: %u,  ", msg_seqno(msg));
1339                 pr_cont("Outstanding acks: %lu\n",
1340                         (unsigned long) TIPC_SKB_CB(buf)->handle);
1341
1342                 n_ptr = tipc_bclink_retransmit_to();
1343                 tipc_node_lock(n_ptr);
1344
1345                 tipc_addr_string_fill(addr_string, n_ptr->addr);
1346                 pr_info("Broadcast link info for %s\n", addr_string);
1347                 pr_info("Reception permitted: %d,  Acked: %u\n",
1348                         n_ptr->bclink.recv_permitted,
1349                         n_ptr->bclink.acked);
1350                 pr_info("Last in: %u,  Oos state: %u,  Last sent: %u\n",
1351                         n_ptr->bclink.last_in,
1352                         n_ptr->bclink.oos_state,
1353                         n_ptr->bclink.last_sent);
1354
1355                 tipc_k_signal((Handler)link_reset_all, (unsigned long)n_ptr->addr);
1356
1357                 tipc_node_unlock(n_ptr);
1358
1359                 l_ptr->stale_count = 0;
1360         }
1361 }
1362
1363 void tipc_link_retransmit(struct tipc_link *l_ptr, struct sk_buff *buf,
1364                           u32 retransmits)
1365 {
1366         struct tipc_msg *msg;
1367
1368         if (!buf)
1369                 return;
1370
1371         msg = buf_msg(buf);
1372
1373         if (tipc_bearer_blocked(l_ptr->b_ptr)) {
1374                 if (l_ptr->retransm_queue_size == 0) {
1375                         l_ptr->retransm_queue_head = msg_seqno(msg);
1376                         l_ptr->retransm_queue_size = retransmits;
1377                 } else {
1378                         pr_err("Unexpected retransmit on link %s (qsize=%d)\n",
1379                                l_ptr->name, l_ptr->retransm_queue_size);
1380                 }
1381                 return;
1382         } else {
1383                 /* Detect repeated retransmit failures on unblocked bearer */
1384                 if (l_ptr->last_retransmitted == msg_seqno(msg)) {
1385                         if (++l_ptr->stale_count > 100) {
1386                                 link_retransmit_failure(l_ptr, buf);
1387                                 return;
1388                         }
1389                 } else {
1390                         l_ptr->last_retransmitted = msg_seqno(msg);
1391                         l_ptr->stale_count = 1;
1392                 }
1393         }
1394
1395         while (retransmits && (buf != l_ptr->next_out) && buf) {
1396                 msg = buf_msg(buf);
1397                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1398                 msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1399                 tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr);
1400                 buf = buf->next;
1401                 retransmits--;
1402                 l_ptr->stats.retransmitted++;
1403         }
1404
1405         l_ptr->retransm_queue_head = l_ptr->retransm_queue_size = 0;
1406 }
1407
1408 /**
1409  * link_insert_deferred_queue - insert deferred messages back into receive chain
1410  */
1411 static struct sk_buff *link_insert_deferred_queue(struct tipc_link *l_ptr,
1412                                                   struct sk_buff *buf)
1413 {
1414         u32 seq_no;
1415
1416         if (l_ptr->oldest_deferred_in == NULL)
1417                 return buf;
1418
1419         seq_no = buf_seqno(l_ptr->oldest_deferred_in);
1420         if (seq_no == mod(l_ptr->next_in_no)) {
1421                 l_ptr->newest_deferred_in->next = buf;
1422                 buf = l_ptr->oldest_deferred_in;
1423                 l_ptr->oldest_deferred_in = NULL;
1424                 l_ptr->deferred_inqueue_sz = 0;
1425         }
1426         return buf;
1427 }
1428
1429 /**
1430  * link_recv_buf_validate - validate basic format of received message
1431  *
1432  * This routine ensures a TIPC message has an acceptable header, and at least
1433  * as much data as the header indicates it should.  The routine also ensures
1434  * that the entire message header is stored in the main fragment of the message
1435  * buffer, to simplify future access to message header fields.
1436  *
1437  * Note: Having extra info present in the message header or data areas is OK.
1438  * TIPC will ignore the excess, under the assumption that it is optional info
1439  * introduced by a later release of the protocol.
1440  */
1441 static int link_recv_buf_validate(struct sk_buff *buf)
1442 {
1443         static u32 min_data_hdr_size[8] = {
1444                 SHORT_H_SIZE, MCAST_H_SIZE, NAMED_H_SIZE, BASIC_H_SIZE,
1445                 MAX_H_SIZE, MAX_H_SIZE, MAX_H_SIZE, MAX_H_SIZE
1446                 };
1447
1448         struct tipc_msg *msg;
1449         u32 tipc_hdr[2];
1450         u32 size;
1451         u32 hdr_size;
1452         u32 min_hdr_size;
1453
1454         if (unlikely(buf->len < MIN_H_SIZE))
1455                 return 0;
1456
1457         msg = skb_header_pointer(buf, 0, sizeof(tipc_hdr), tipc_hdr);
1458         if (msg == NULL)
1459                 return 0;
1460
1461         if (unlikely(msg_version(msg) != TIPC_VERSION))
1462                 return 0;
1463
1464         size = msg_size(msg);
1465         hdr_size = msg_hdr_sz(msg);
1466         min_hdr_size = msg_isdata(msg) ?
1467                 min_data_hdr_size[msg_type(msg)] : INT_H_SIZE;
1468
1469         if (unlikely((hdr_size < min_hdr_size) ||
1470                      (size < hdr_size) ||
1471                      (buf->len < size) ||
1472                      (size - hdr_size > TIPC_MAX_USER_MSG_SIZE)))
1473                 return 0;
1474
1475         return pskb_may_pull(buf, hdr_size);
1476 }
1477
1478 /**
1479  * tipc_recv_msg - process TIPC messages arriving from off-node
1480  * @head: pointer to message buffer chain
1481  * @tb_ptr: pointer to bearer message arrived on
1482  *
1483  * Invoked with no locks held.  Bearer pointer must point to a valid bearer
1484  * structure (i.e. cannot be NULL), but bearer can be inactive.
1485  */
1486 void tipc_recv_msg(struct sk_buff *head, struct tipc_bearer *b_ptr)
1487 {
1488         read_lock_bh(&tipc_net_lock);
1489         while (head) {
1490                 struct tipc_node *n_ptr;
1491                 struct tipc_link *l_ptr;
1492                 struct sk_buff *crs;
1493                 struct sk_buff *buf = head;
1494                 struct tipc_msg *msg;
1495                 u32 seq_no;
1496                 u32 ackd;
1497                 u32 released = 0;
1498                 int type;
1499
1500                 head = head->next;
1501
1502                 /* Ensure bearer is still enabled */
1503                 if (unlikely(!b_ptr->active))
1504                         goto discard;
1505
1506                 /* Ensure message is well-formed */
1507                 if (unlikely(!link_recv_buf_validate(buf)))
1508                         goto discard;
1509
1510                 /* Ensure message data is a single contiguous unit */
1511                 if (unlikely(skb_linearize(buf)))
1512                         goto discard;
1513
1514                 /* Handle arrival of a non-unicast link message */
1515                 msg = buf_msg(buf);
1516
1517                 if (unlikely(msg_non_seq(msg))) {
1518                         if (msg_user(msg) ==  LINK_CONFIG)
1519                                 tipc_disc_recv_msg(buf, b_ptr);
1520                         else
1521                                 tipc_bclink_recv_pkt(buf);
1522                         continue;
1523                 }
1524
1525                 /* Discard unicast link messages destined for another node */
1526                 if (unlikely(!msg_short(msg) &&
1527                              (msg_destnode(msg) != tipc_own_addr)))
1528                         goto discard;
1529
1530                 /* Locate neighboring node that sent message */
1531                 n_ptr = tipc_node_find(msg_prevnode(msg));
1532                 if (unlikely(!n_ptr))
1533                         goto discard;
1534                 tipc_node_lock(n_ptr);
1535
1536                 /* Locate unicast link endpoint that should handle message */
1537                 l_ptr = n_ptr->links[b_ptr->identity];
1538                 if (unlikely(!l_ptr))
1539                         goto unlock_discard;
1540
1541                 /* Verify that communication with node is currently allowed */
1542                 if ((n_ptr->block_setup & WAIT_PEER_DOWN) &&
1543                         msg_user(msg) == LINK_PROTOCOL &&
1544                         (msg_type(msg) == RESET_MSG ||
1545                                         msg_type(msg) == ACTIVATE_MSG) &&
1546                         !msg_redundant_link(msg))
1547                         n_ptr->block_setup &= ~WAIT_PEER_DOWN;
1548
1549                 if (n_ptr->block_setup)
1550                         goto unlock_discard;
1551
1552                 /* Validate message sequence number info */
1553                 seq_no = msg_seqno(msg);
1554                 ackd = msg_ack(msg);
1555
1556                 /* Release acked messages */
1557                 if (n_ptr->bclink.recv_permitted)
1558                         tipc_bclink_acknowledge(n_ptr, msg_bcast_ack(msg));
1559
1560                 crs = l_ptr->first_out;
1561                 while ((crs != l_ptr->next_out) &&
1562                        less_eq(buf_seqno(crs), ackd)) {
1563                         struct sk_buff *next = crs->next;
1564
1565                         kfree_skb(crs);
1566                         crs = next;
1567                         released++;
1568                 }
1569                 if (released) {
1570                         l_ptr->first_out = crs;
1571                         l_ptr->out_queue_size -= released;
1572                 }
1573
1574                 /* Try sending any messages link endpoint has pending */
1575                 if (unlikely(l_ptr->next_out))
1576                         tipc_link_push_queue(l_ptr);
1577                 if (unlikely(!list_empty(&l_ptr->waiting_ports)))
1578                         tipc_link_wakeup_ports(l_ptr, 0);
1579                 if (unlikely(++l_ptr->unacked_window >= TIPC_MIN_LINK_WIN)) {
1580                         l_ptr->stats.sent_acks++;
1581                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
1582                 }
1583
1584                 /* Now (finally!) process the incoming message */
1585 protocol_check:
1586                 if (unlikely(!link_working_working(l_ptr))) {
1587                         if (msg_user(msg) == LINK_PROTOCOL) {
1588                                 link_recv_proto_msg(l_ptr, buf);
1589                                 head = link_insert_deferred_queue(l_ptr, head);
1590                                 tipc_node_unlock(n_ptr);
1591                                 continue;
1592                         }
1593
1594                         /* Traffic message. Conditionally activate link */
1595                         link_state_event(l_ptr, TRAFFIC_MSG_EVT);
1596
1597                         if (link_working_working(l_ptr)) {
1598                                 /* Re-insert buffer in front of queue */
1599                                 buf->next = head;
1600                                 head = buf;
1601                                 tipc_node_unlock(n_ptr);
1602                                 continue;
1603                         }
1604                         goto unlock_discard;
1605                 }
1606
1607                 /* Link is now in state WORKING_WORKING */
1608                 if (unlikely(seq_no != mod(l_ptr->next_in_no))) {
1609                         link_handle_out_of_seq_msg(l_ptr, buf);
1610                         head = link_insert_deferred_queue(l_ptr, head);
1611                         tipc_node_unlock(n_ptr);
1612                         continue;
1613                 }
1614                 l_ptr->next_in_no++;
1615                 if (unlikely(l_ptr->oldest_deferred_in))
1616                         head = link_insert_deferred_queue(l_ptr, head);
1617 deliver:
1618                 if (likely(msg_isdata(msg))) {
1619                         tipc_node_unlock(n_ptr);
1620                         tipc_port_recv_msg(buf);
1621                         continue;
1622                 }
1623                 switch (msg_user(msg)) {
1624                         int ret;
1625                 case MSG_BUNDLER:
1626                         l_ptr->stats.recv_bundles++;
1627                         l_ptr->stats.recv_bundled += msg_msgcnt(msg);
1628                         tipc_node_unlock(n_ptr);
1629                         tipc_link_recv_bundle(buf);
1630                         continue;
1631                 case NAME_DISTRIBUTOR:
1632                         n_ptr->bclink.recv_permitted = true;
1633                         tipc_node_unlock(n_ptr);
1634                         tipc_named_recv(buf);
1635                         continue;
1636                 case BCAST_PROTOCOL:
1637                         tipc_link_recv_sync(n_ptr, buf);
1638                         tipc_node_unlock(n_ptr);
1639                         continue;
1640                 case CONN_MANAGER:
1641                         tipc_node_unlock(n_ptr);
1642                         tipc_port_recv_proto_msg(buf);
1643                         continue;
1644                 case MSG_FRAGMENTER:
1645                         l_ptr->stats.recv_fragments++;
1646                         ret = tipc_link_recv_fragment(&l_ptr->reasm_head,
1647                                                       &l_ptr->reasm_tail,
1648                                                       &buf);
1649                         if (ret == LINK_REASM_COMPLETE) {
1650                                 l_ptr->stats.recv_fragmented++;
1651                                 msg = buf_msg(buf);
1652                                 goto deliver;
1653                         }
1654                         if (ret == LINK_REASM_ERROR)
1655                                 tipc_link_reset(l_ptr);
1656                         tipc_node_unlock(n_ptr);
1657                         continue;
1658                 case CHANGEOVER_PROTOCOL:
1659                         type = msg_type(msg);
1660                         if (link_recv_changeover_msg(&l_ptr, &buf)) {
1661                                 msg = buf_msg(buf);
1662                                 seq_no = msg_seqno(msg);
1663                                 if (type == ORIGINAL_MSG)
1664                                         goto deliver;
1665                                 goto protocol_check;
1666                         }
1667                         break;
1668                 default:
1669                         kfree_skb(buf);
1670                         buf = NULL;
1671                         break;
1672                 }
1673                 tipc_node_unlock(n_ptr);
1674                 tipc_net_route_msg(buf);
1675                 continue;
1676 unlock_discard:
1677
1678                 tipc_node_unlock(n_ptr);
1679 discard:
1680                 kfree_skb(buf);
1681         }
1682         read_unlock_bh(&tipc_net_lock);
1683 }
1684
1685 /**
1686  * tipc_link_defer_pkt - Add out-of-sequence message to deferred reception queue
1687  *
1688  * Returns increase in queue length (i.e. 0 or 1)
1689  */
1690 u32 tipc_link_defer_pkt(struct sk_buff **head, struct sk_buff **tail,
1691                         struct sk_buff *buf)
1692 {
1693         struct sk_buff *queue_buf;
1694         struct sk_buff **prev;
1695         u32 seq_no = buf_seqno(buf);
1696
1697         buf->next = NULL;
1698
1699         /* Empty queue ? */
1700         if (*head == NULL) {
1701                 *head = *tail = buf;
1702                 return 1;
1703         }
1704
1705         /* Last ? */
1706         if (less(buf_seqno(*tail), seq_no)) {
1707                 (*tail)->next = buf;
1708                 *tail = buf;
1709                 return 1;
1710         }
1711
1712         /* Locate insertion point in queue, then insert; discard if duplicate */
1713         prev = head;
1714         queue_buf = *head;
1715         for (;;) {
1716                 u32 curr_seqno = buf_seqno(queue_buf);
1717
1718                 if (seq_no == curr_seqno) {
1719                         kfree_skb(buf);
1720                         return 0;
1721                 }
1722
1723                 if (less(seq_no, curr_seqno))
1724                         break;
1725
1726                 prev = &queue_buf->next;
1727                 queue_buf = queue_buf->next;
1728         }
1729
1730         buf->next = queue_buf;
1731         *prev = buf;
1732         return 1;
1733 }
1734
1735 /*
1736  * link_handle_out_of_seq_msg - handle arrival of out-of-sequence packet
1737  */
1738 static void link_handle_out_of_seq_msg(struct tipc_link *l_ptr,
1739                                        struct sk_buff *buf)
1740 {
1741         u32 seq_no = buf_seqno(buf);
1742
1743         if (likely(msg_user(buf_msg(buf)) == LINK_PROTOCOL)) {
1744                 link_recv_proto_msg(l_ptr, buf);
1745                 return;
1746         }
1747
1748         /* Record OOS packet arrival (force mismatch on next timeout) */
1749         l_ptr->checkpoint--;
1750
1751         /*
1752          * Discard packet if a duplicate; otherwise add it to deferred queue
1753          * and notify peer of gap as per protocol specification
1754          */
1755         if (less(seq_no, mod(l_ptr->next_in_no))) {
1756                 l_ptr->stats.duplicates++;
1757                 kfree_skb(buf);
1758                 return;
1759         }
1760
1761         if (tipc_link_defer_pkt(&l_ptr->oldest_deferred_in,
1762                                 &l_ptr->newest_deferred_in, buf)) {
1763                 l_ptr->deferred_inqueue_sz++;
1764                 l_ptr->stats.deferred_recv++;
1765                 if ((l_ptr->deferred_inqueue_sz % 16) == 1)
1766                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
1767         } else
1768                 l_ptr->stats.duplicates++;
1769 }
1770
1771 /*
1772  * Send protocol message to the other endpoint.
1773  */
1774 void tipc_link_send_proto_msg(struct tipc_link *l_ptr, u32 msg_typ,
1775                               int probe_msg, u32 gap, u32 tolerance,
1776                               u32 priority, u32 ack_mtu)
1777 {
1778         struct sk_buff *buf = NULL;
1779         struct tipc_msg *msg = l_ptr->pmsg;
1780         u32 msg_size = sizeof(l_ptr->proto_msg);
1781         int r_flag;
1782
1783         /* Discard any previous message that was deferred due to congestion */
1784         if (l_ptr->proto_msg_queue) {
1785                 kfree_skb(l_ptr->proto_msg_queue);
1786                 l_ptr->proto_msg_queue = NULL;
1787         }
1788
1789         if (link_blocked(l_ptr))
1790                 return;
1791
1792         /* Abort non-RESET send if communication with node is prohibited */
1793         if ((l_ptr->owner->block_setup) && (msg_typ != RESET_MSG))
1794                 return;
1795
1796         /* Create protocol message with "out-of-sequence" sequence number */
1797         msg_set_type(msg, msg_typ);
1798         msg_set_net_plane(msg, l_ptr->b_ptr->net_plane);
1799         msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1800         msg_set_last_bcast(msg, tipc_bclink_get_last_sent());
1801
1802         if (msg_typ == STATE_MSG) {
1803                 u32 next_sent = mod(l_ptr->next_out_no);
1804
1805                 if (!tipc_link_is_up(l_ptr))
1806                         return;
1807                 if (l_ptr->next_out)
1808                         next_sent = buf_seqno(l_ptr->next_out);
1809                 msg_set_next_sent(msg, next_sent);
1810                 if (l_ptr->oldest_deferred_in) {
1811                         u32 rec = buf_seqno(l_ptr->oldest_deferred_in);
1812                         gap = mod(rec - mod(l_ptr->next_in_no));
1813                 }
1814                 msg_set_seq_gap(msg, gap);
1815                 if (gap)
1816                         l_ptr->stats.sent_nacks++;
1817                 msg_set_link_tolerance(msg, tolerance);
1818                 msg_set_linkprio(msg, priority);
1819                 msg_set_max_pkt(msg, ack_mtu);
1820                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1821                 msg_set_probe(msg, probe_msg != 0);
1822                 if (probe_msg) {
1823                         u32 mtu = l_ptr->max_pkt;
1824
1825                         if ((mtu < l_ptr->max_pkt_target) &&
1826                             link_working_working(l_ptr) &&
1827                             l_ptr->fsm_msg_cnt) {
1828                                 msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
1829                                 if (l_ptr->max_pkt_probes == 10) {
1830                                         l_ptr->max_pkt_target = (msg_size - 4);
1831                                         l_ptr->max_pkt_probes = 0;
1832                                         msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
1833                                 }
1834                                 l_ptr->max_pkt_probes++;
1835                         }
1836
1837                         l_ptr->stats.sent_probes++;
1838                 }
1839                 l_ptr->stats.sent_states++;
1840         } else {                /* RESET_MSG or ACTIVATE_MSG */
1841                 msg_set_ack(msg, mod(l_ptr->reset_checkpoint - 1));
1842                 msg_set_seq_gap(msg, 0);
1843                 msg_set_next_sent(msg, 1);
1844                 msg_set_probe(msg, 0);
1845                 msg_set_link_tolerance(msg, l_ptr->tolerance);
1846                 msg_set_linkprio(msg, l_ptr->priority);
1847                 msg_set_max_pkt(msg, l_ptr->max_pkt_target);
1848         }
1849
1850         r_flag = (l_ptr->owner->working_links > tipc_link_is_up(l_ptr));
1851         msg_set_redundant_link(msg, r_flag);
1852         msg_set_linkprio(msg, l_ptr->priority);
1853         msg_set_size(msg, msg_size);
1854
1855         msg_set_seqno(msg, mod(l_ptr->next_out_no + (0xffff/2)));
1856
1857         buf = tipc_buf_acquire(msg_size);
1858         if (!buf)
1859                 return;
1860
1861         skb_copy_to_linear_data(buf, msg, sizeof(l_ptr->proto_msg));
1862         buf->priority = TC_PRIO_CONTROL;
1863
1864         /* Defer message if bearer is already blocked */
1865         if (tipc_bearer_blocked(l_ptr->b_ptr)) {
1866                 l_ptr->proto_msg_queue = buf;
1867                 return;
1868         }
1869
1870         tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr);
1871         l_ptr->unacked_window = 0;
1872         kfree_skb(buf);
1873 }
1874
1875 /*
1876  * Receive protocol message :
1877  * Note that network plane id propagates through the network, and may
1878  * change at any time. The node with lowest address rules
1879  */
1880 static void link_recv_proto_msg(struct tipc_link *l_ptr, struct sk_buff *buf)
1881 {
1882         u32 rec_gap = 0;
1883         u32 max_pkt_info;
1884         u32 max_pkt_ack;
1885         u32 msg_tol;
1886         struct tipc_msg *msg = buf_msg(buf);
1887
1888         if (link_blocked(l_ptr))
1889                 goto exit;
1890
1891         /* record unnumbered packet arrival (force mismatch on next timeout) */
1892         l_ptr->checkpoint--;
1893
1894         if (l_ptr->b_ptr->net_plane != msg_net_plane(msg))
1895                 if (tipc_own_addr > msg_prevnode(msg))
1896                         l_ptr->b_ptr->net_plane = msg_net_plane(msg);
1897
1898         l_ptr->owner->permit_changeover = msg_redundant_link(msg);
1899
1900         switch (msg_type(msg)) {
1901
1902         case RESET_MSG:
1903                 if (!link_working_unknown(l_ptr) &&
1904                     (l_ptr->peer_session != INVALID_SESSION)) {
1905                         if (less_eq(msg_session(msg), l_ptr->peer_session))
1906                                 break; /* duplicate or old reset: ignore */
1907                 }
1908
1909                 if (!msg_redundant_link(msg) && (link_working_working(l_ptr) ||
1910                                 link_working_unknown(l_ptr))) {
1911                         /*
1912                          * peer has lost contact -- don't allow peer's links
1913                          * to reactivate before we recognize loss & clean up
1914                          */
1915                         l_ptr->owner->block_setup = WAIT_NODE_DOWN;
1916                 }
1917
1918                 link_state_event(l_ptr, RESET_MSG);
1919
1920                 /* fall thru' */
1921         case ACTIVATE_MSG:
1922                 /* Update link settings according other endpoint's values */
1923                 strcpy((strrchr(l_ptr->name, ':') + 1), (char *)msg_data(msg));
1924
1925                 msg_tol = msg_link_tolerance(msg);
1926                 if (msg_tol > l_ptr->tolerance)
1927                         link_set_supervision_props(l_ptr, msg_tol);
1928
1929                 if (msg_linkprio(msg) > l_ptr->priority)
1930                         l_ptr->priority = msg_linkprio(msg);
1931
1932                 max_pkt_info = msg_max_pkt(msg);
1933                 if (max_pkt_info) {
1934                         if (max_pkt_info < l_ptr->max_pkt_target)
1935                                 l_ptr->max_pkt_target = max_pkt_info;
1936                         if (l_ptr->max_pkt > l_ptr->max_pkt_target)
1937                                 l_ptr->max_pkt = l_ptr->max_pkt_target;
1938                 } else {
1939                         l_ptr->max_pkt = l_ptr->max_pkt_target;
1940                 }
1941
1942                 /* Synchronize broadcast link info, if not done previously */
1943                 if (!tipc_node_is_up(l_ptr->owner)) {
1944                         l_ptr->owner->bclink.last_sent =
1945                                 l_ptr->owner->bclink.last_in =
1946                                 msg_last_bcast(msg);
1947                         l_ptr->owner->bclink.oos_state = 0;
1948                 }
1949
1950                 l_ptr->peer_session = msg_session(msg);
1951                 l_ptr->peer_bearer_id = msg_bearer_id(msg);
1952
1953                 if (msg_type(msg) == ACTIVATE_MSG)
1954                         link_state_event(l_ptr, ACTIVATE_MSG);
1955                 break;
1956         case STATE_MSG:
1957
1958                 msg_tol = msg_link_tolerance(msg);
1959                 if (msg_tol)
1960                         link_set_supervision_props(l_ptr, msg_tol);
1961
1962                 if (msg_linkprio(msg) &&
1963                     (msg_linkprio(msg) != l_ptr->priority)) {
1964                         pr_warn("%s<%s>, priority change %u->%u\n",
1965                                 link_rst_msg, l_ptr->name, l_ptr->priority,
1966                                 msg_linkprio(msg));
1967                         l_ptr->priority = msg_linkprio(msg);
1968                         tipc_link_reset(l_ptr); /* Enforce change to take effect */
1969                         break;
1970                 }
1971                 link_state_event(l_ptr, TRAFFIC_MSG_EVT);
1972                 l_ptr->stats.recv_states++;
1973                 if (link_reset_unknown(l_ptr))
1974                         break;
1975
1976                 if (less_eq(mod(l_ptr->next_in_no), msg_next_sent(msg))) {
1977                         rec_gap = mod(msg_next_sent(msg) -
1978                                       mod(l_ptr->next_in_no));
1979                 }
1980
1981                 max_pkt_ack = msg_max_pkt(msg);
1982                 if (max_pkt_ack > l_ptr->max_pkt) {
1983                         l_ptr->max_pkt = max_pkt_ack;
1984                         l_ptr->max_pkt_probes = 0;
1985                 }
1986
1987                 max_pkt_ack = 0;
1988                 if (msg_probe(msg)) {
1989                         l_ptr->stats.recv_probes++;
1990                         if (msg_size(msg) > sizeof(l_ptr->proto_msg))
1991                                 max_pkt_ack = msg_size(msg);
1992                 }
1993
1994                 /* Protocol message before retransmits, reduce loss risk */
1995                 if (l_ptr->owner->bclink.recv_permitted)
1996                         tipc_bclink_update_link_state(l_ptr->owner,
1997                                                       msg_last_bcast(msg));
1998
1999                 if (rec_gap || (msg_probe(msg))) {
2000                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
2001                                                  0, rec_gap, 0, 0, max_pkt_ack);
2002                 }
2003                 if (msg_seq_gap(msg)) {
2004                         l_ptr->stats.recv_nacks++;
2005                         tipc_link_retransmit(l_ptr, l_ptr->first_out,
2006                                              msg_seq_gap(msg));
2007                 }
2008                 break;
2009         }
2010 exit:
2011         kfree_skb(buf);
2012 }
2013
2014
2015 /*
2016  * tipc_link_tunnel(): Send one message via a link belonging to
2017  * another bearer. Owner node is locked.
2018  */
2019 static void tipc_link_tunnel(struct tipc_link *l_ptr,
2020                              struct tipc_msg *tunnel_hdr, struct tipc_msg *msg,
2021                              u32 selector)
2022 {
2023         struct tipc_link *tunnel;
2024         struct sk_buff *buf;
2025         u32 length = msg_size(msg);
2026
2027         tunnel = l_ptr->owner->active_links[selector & 1];
2028         if (!tipc_link_is_up(tunnel)) {
2029                 pr_warn("%stunnel link no longer available\n", link_co_err);
2030                 return;
2031         }
2032         msg_set_size(tunnel_hdr, length + INT_H_SIZE);
2033         buf = tipc_buf_acquire(length + INT_H_SIZE);
2034         if (!buf) {
2035                 pr_warn("%sunable to send tunnel msg\n", link_co_err);
2036                 return;
2037         }
2038         skb_copy_to_linear_data(buf, tunnel_hdr, INT_H_SIZE);
2039         skb_copy_to_linear_data_offset(buf, INT_H_SIZE, msg, length);
2040         tipc_link_send_buf(tunnel, buf);
2041 }
2042
2043
2044
2045 /*
2046  * changeover(): Send whole message queue via the remaining link
2047  *               Owner node is locked.
2048  */
2049 void tipc_link_changeover(struct tipc_link *l_ptr)
2050 {
2051         u32 msgcount = l_ptr->out_queue_size;
2052         struct sk_buff *crs = l_ptr->first_out;
2053         struct tipc_link *tunnel = l_ptr->owner->active_links[0];
2054         struct tipc_msg tunnel_hdr;
2055         int split_bundles;
2056
2057         if (!tunnel)
2058                 return;
2059
2060         if (!l_ptr->owner->permit_changeover) {
2061                 pr_warn("%speer did not permit changeover\n", link_co_err);
2062                 return;
2063         }
2064
2065         tipc_msg_init(&tunnel_hdr, CHANGEOVER_PROTOCOL,
2066                  ORIGINAL_MSG, INT_H_SIZE, l_ptr->addr);
2067         msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
2068         msg_set_msgcnt(&tunnel_hdr, msgcount);
2069
2070         if (!l_ptr->first_out) {
2071                 struct sk_buff *buf;
2072
2073                 buf = tipc_buf_acquire(INT_H_SIZE);
2074                 if (buf) {
2075                         skb_copy_to_linear_data(buf, &tunnel_hdr, INT_H_SIZE);
2076                         msg_set_size(&tunnel_hdr, INT_H_SIZE);
2077                         tipc_link_send_buf(tunnel, buf);
2078                 } else {
2079                         pr_warn("%sunable to send changeover msg\n",
2080                                 link_co_err);
2081                 }
2082                 return;
2083         }
2084
2085         split_bundles = (l_ptr->owner->active_links[0] !=
2086                          l_ptr->owner->active_links[1]);
2087
2088         while (crs) {
2089                 struct tipc_msg *msg = buf_msg(crs);
2090
2091                 if ((msg_user(msg) == MSG_BUNDLER) && split_bundles) {
2092                         struct tipc_msg *m = msg_get_wrapped(msg);
2093                         unchar *pos = (unchar *)m;
2094
2095                         msgcount = msg_msgcnt(msg);
2096                         while (msgcount--) {
2097                                 msg_set_seqno(m, msg_seqno(msg));
2098                                 tipc_link_tunnel(l_ptr, &tunnel_hdr, m,
2099                                                  msg_link_selector(m));
2100                                 pos += align(msg_size(m));
2101                                 m = (struct tipc_msg *)pos;
2102                         }
2103                 } else {
2104                         tipc_link_tunnel(l_ptr, &tunnel_hdr, msg,
2105                                          msg_link_selector(msg));
2106                 }
2107                 crs = crs->next;
2108         }
2109 }
2110
2111 void tipc_link_send_duplicate(struct tipc_link *l_ptr, struct tipc_link *tunnel)
2112 {
2113         struct sk_buff *iter;
2114         struct tipc_msg tunnel_hdr;
2115
2116         tipc_msg_init(&tunnel_hdr, CHANGEOVER_PROTOCOL,
2117                  DUPLICATE_MSG, INT_H_SIZE, l_ptr->addr);
2118         msg_set_msgcnt(&tunnel_hdr, l_ptr->out_queue_size);
2119         msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
2120         iter = l_ptr->first_out;
2121         while (iter) {
2122                 struct sk_buff *outbuf;
2123                 struct tipc_msg *msg = buf_msg(iter);
2124                 u32 length = msg_size(msg);
2125
2126                 if (msg_user(msg) == MSG_BUNDLER)
2127                         msg_set_type(msg, CLOSED_MSG);
2128                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));   /* Update */
2129                 msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
2130                 msg_set_size(&tunnel_hdr, length + INT_H_SIZE);
2131                 outbuf = tipc_buf_acquire(length + INT_H_SIZE);
2132                 if (outbuf == NULL) {
2133                         pr_warn("%sunable to send duplicate msg\n",
2134                                 link_co_err);
2135                         return;
2136                 }
2137                 skb_copy_to_linear_data(outbuf, &tunnel_hdr, INT_H_SIZE);
2138                 skb_copy_to_linear_data_offset(outbuf, INT_H_SIZE, iter->data,
2139                                                length);
2140                 tipc_link_send_buf(tunnel, outbuf);
2141                 if (!tipc_link_is_up(l_ptr))
2142                         return;
2143                 iter = iter->next;
2144         }
2145 }
2146
2147 /**
2148  * buf_extract - extracts embedded TIPC message from another message
2149  * @skb: encapsulating message buffer
2150  * @from_pos: offset to extract from
2151  *
2152  * Returns a new message buffer containing an embedded message.  The
2153  * encapsulating message itself is left unchanged.
2154  */
2155 static struct sk_buff *buf_extract(struct sk_buff *skb, u32 from_pos)
2156 {
2157         struct tipc_msg *msg = (struct tipc_msg *)(skb->data + from_pos);
2158         u32 size = msg_size(msg);
2159         struct sk_buff *eb;
2160
2161         eb = tipc_buf_acquire(size);
2162         if (eb)
2163                 skb_copy_to_linear_data(eb, msg, size);
2164         return eb;
2165 }
2166
2167 /*
2168  *  link_recv_changeover_msg(): Receive tunneled packet sent
2169  *  via other link. Node is locked. Return extracted buffer.
2170  */
2171 static int link_recv_changeover_msg(struct tipc_link **l_ptr,
2172                                     struct sk_buff **buf)
2173 {
2174         struct sk_buff *tunnel_buf = *buf;
2175         struct tipc_link *dest_link;
2176         struct tipc_msg *msg;
2177         struct tipc_msg *tunnel_msg = buf_msg(tunnel_buf);
2178         u32 msg_typ = msg_type(tunnel_msg);
2179         u32 msg_count = msg_msgcnt(tunnel_msg);
2180         u32 bearer_id = msg_bearer_id(tunnel_msg);
2181
2182         if (bearer_id >= MAX_BEARERS)
2183                 goto exit;
2184         dest_link = (*l_ptr)->owner->links[bearer_id];
2185         if (!dest_link)
2186                 goto exit;
2187         if (dest_link == *l_ptr) {
2188                 pr_err("Unexpected changeover message on link <%s>\n",
2189                        (*l_ptr)->name);
2190                 goto exit;
2191         }
2192         *l_ptr = dest_link;
2193         msg = msg_get_wrapped(tunnel_msg);
2194
2195         if (msg_typ == DUPLICATE_MSG) {
2196                 if (less(msg_seqno(msg), mod(dest_link->next_in_no)))
2197                         goto exit;
2198                 *buf = buf_extract(tunnel_buf, INT_H_SIZE);
2199                 if (*buf == NULL) {
2200                         pr_warn("%sduplicate msg dropped\n", link_co_err);
2201                         goto exit;
2202                 }
2203                 kfree_skb(tunnel_buf);
2204                 return 1;
2205         }
2206
2207         /* First original message ?: */
2208         if (tipc_link_is_up(dest_link)) {
2209                 pr_info("%s<%s>, changeover initiated by peer\n", link_rst_msg,
2210                         dest_link->name);
2211                 tipc_link_reset(dest_link);
2212                 dest_link->exp_msg_count = msg_count;
2213                 if (!msg_count)
2214                         goto exit;
2215         } else if (dest_link->exp_msg_count == START_CHANGEOVER) {
2216                 dest_link->exp_msg_count = msg_count;
2217                 if (!msg_count)
2218                         goto exit;
2219         }
2220
2221         /* Receive original message */
2222         if (dest_link->exp_msg_count == 0) {
2223                 pr_warn("%sgot too many tunnelled messages\n", link_co_err);
2224                 goto exit;
2225         }
2226         dest_link->exp_msg_count--;
2227         if (less(msg_seqno(msg), dest_link->reset_checkpoint)) {
2228                 goto exit;
2229         } else {
2230                 *buf = buf_extract(tunnel_buf, INT_H_SIZE);
2231                 if (*buf != NULL) {
2232                         kfree_skb(tunnel_buf);
2233                         return 1;
2234                 } else {
2235                         pr_warn("%soriginal msg dropped\n", link_co_err);
2236                 }
2237         }
2238 exit:
2239         *buf = NULL;
2240         kfree_skb(tunnel_buf);
2241         return 0;
2242 }
2243
2244 /*
2245  *  Bundler functionality:
2246  */
2247 void tipc_link_recv_bundle(struct sk_buff *buf)
2248 {
2249         u32 msgcount = msg_msgcnt(buf_msg(buf));
2250         u32 pos = INT_H_SIZE;
2251         struct sk_buff *obuf;
2252
2253         while (msgcount--) {
2254                 obuf = buf_extract(buf, pos);
2255                 if (obuf == NULL) {
2256                         pr_warn("Link unable to unbundle message(s)\n");
2257                         break;
2258                 }
2259                 pos += align(msg_size(buf_msg(obuf)));
2260                 tipc_net_route_msg(obuf);
2261         }
2262         kfree_skb(buf);
2263 }
2264
2265 /*
2266  *  Fragmentation/defragmentation:
2267  */
2268
2269 /*
2270  * link_send_long_buf: Entry for buffers needing fragmentation.
2271  * The buffer is complete, inclusive total message length.
2272  * Returns user data length.
2273  */
2274 static int link_send_long_buf(struct tipc_link *l_ptr, struct sk_buff *buf)
2275 {
2276         struct sk_buff *buf_chain = NULL;
2277         struct sk_buff *buf_chain_tail = (struct sk_buff *)&buf_chain;
2278         struct tipc_msg *inmsg = buf_msg(buf);
2279         struct tipc_msg fragm_hdr;
2280         u32 insize = msg_size(inmsg);
2281         u32 dsz = msg_data_sz(inmsg);
2282         unchar *crs = buf->data;
2283         u32 rest = insize;
2284         u32 pack_sz = l_ptr->max_pkt;
2285         u32 fragm_sz = pack_sz - INT_H_SIZE;
2286         u32 fragm_no = 0;
2287         u32 destaddr;
2288
2289         if (msg_short(inmsg))
2290                 destaddr = l_ptr->addr;
2291         else
2292                 destaddr = msg_destnode(inmsg);
2293
2294         /* Prepare reusable fragment header: */
2295         tipc_msg_init(&fragm_hdr, MSG_FRAGMENTER, FIRST_FRAGMENT,
2296                  INT_H_SIZE, destaddr);
2297
2298         /* Chop up message: */
2299         while (rest > 0) {
2300                 struct sk_buff *fragm;
2301
2302                 if (rest <= fragm_sz) {
2303                         fragm_sz = rest;
2304                         msg_set_type(&fragm_hdr, LAST_FRAGMENT);
2305                 }
2306                 fragm = tipc_buf_acquire(fragm_sz + INT_H_SIZE);
2307                 if (fragm == NULL) {
2308                         kfree_skb(buf);
2309                         while (buf_chain) {
2310                                 buf = buf_chain;
2311                                 buf_chain = buf_chain->next;
2312                                 kfree_skb(buf);
2313                         }
2314                         return -ENOMEM;
2315                 }
2316                 msg_set_size(&fragm_hdr, fragm_sz + INT_H_SIZE);
2317                 fragm_no++;
2318                 msg_set_fragm_no(&fragm_hdr, fragm_no);
2319                 skb_copy_to_linear_data(fragm, &fragm_hdr, INT_H_SIZE);
2320                 skb_copy_to_linear_data_offset(fragm, INT_H_SIZE, crs,
2321                                                fragm_sz);
2322                 buf_chain_tail->next = fragm;
2323                 buf_chain_tail = fragm;
2324
2325                 rest -= fragm_sz;
2326                 crs += fragm_sz;
2327                 msg_set_type(&fragm_hdr, FRAGMENT);
2328         }
2329         kfree_skb(buf);
2330
2331         /* Append chain of fragments to send queue & send them */
2332         l_ptr->long_msg_seq_no++;
2333         link_add_chain_to_outqueue(l_ptr, buf_chain, l_ptr->long_msg_seq_no);
2334         l_ptr->stats.sent_fragments += fragm_no;
2335         l_ptr->stats.sent_fragmented++;
2336         tipc_link_push_queue(l_ptr);
2337
2338         return dsz;
2339 }
2340
2341 /*
2342  * tipc_link_recv_fragment(): Called with node lock on. Returns
2343  * the reassembled buffer if message is complete.
2344  */
2345 int tipc_link_recv_fragment(struct sk_buff **head, struct sk_buff **tail,
2346                             struct sk_buff **fbuf)
2347 {
2348         struct sk_buff *frag = *fbuf;
2349         struct tipc_msg *msg = buf_msg(frag);
2350         u32 fragid = msg_type(msg);
2351         bool headstolen;
2352         int delta;
2353
2354         skb_pull(frag, msg_hdr_sz(msg));
2355         if (fragid == FIRST_FRAGMENT) {
2356                 if (*head || skb_unclone(frag, GFP_ATOMIC))
2357                         goto out_free;
2358                 *head = frag;
2359                 skb_frag_list_init(*head);
2360                 return 0;
2361         } else if (*head &&
2362                    skb_try_coalesce(*head, frag, &headstolen, &delta)) {
2363                 kfree_skb_partial(frag, headstolen);
2364         } else {
2365                 if (!*head)
2366                         goto out_free;
2367                 if (!skb_has_frag_list(*head))
2368                         skb_shinfo(*head)->frag_list = frag;
2369                 else
2370                         (*tail)->next = frag;
2371                 *tail = frag;
2372                 (*head)->truesize += frag->truesize;
2373         }
2374         if (fragid == LAST_FRAGMENT) {
2375                 *fbuf = *head;
2376                 *tail = *head = NULL;
2377                 return LINK_REASM_COMPLETE;
2378         }
2379         return 0;
2380 out_free:
2381         pr_warn_ratelimited("Link unable to reassemble fragmented message\n");
2382         kfree_skb(*fbuf);
2383         return LINK_REASM_ERROR;
2384 }
2385
2386 static void link_set_supervision_props(struct tipc_link *l_ptr, u32 tolerance)
2387 {
2388         if ((tolerance < TIPC_MIN_LINK_TOL) || (tolerance > TIPC_MAX_LINK_TOL))
2389                 return;
2390
2391         l_ptr->tolerance = tolerance;
2392         l_ptr->continuity_interval =
2393                 ((tolerance / 4) > 500) ? 500 : tolerance / 4;
2394         l_ptr->abort_limit = tolerance / (l_ptr->continuity_interval / 4);
2395 }
2396
2397 void tipc_link_set_queue_limits(struct tipc_link *l_ptr, u32 window)
2398 {
2399         /* Data messages from this node, inclusive FIRST_FRAGM */
2400         l_ptr->queue_limit[TIPC_LOW_IMPORTANCE] = window;
2401         l_ptr->queue_limit[TIPC_MEDIUM_IMPORTANCE] = (window / 3) * 4;
2402         l_ptr->queue_limit[TIPC_HIGH_IMPORTANCE] = (window / 3) * 5;
2403         l_ptr->queue_limit[TIPC_CRITICAL_IMPORTANCE] = (window / 3) * 6;
2404         /* Transiting data messages,inclusive FIRST_FRAGM */
2405         l_ptr->queue_limit[TIPC_LOW_IMPORTANCE + 4] = 300;
2406         l_ptr->queue_limit[TIPC_MEDIUM_IMPORTANCE + 4] = 600;
2407         l_ptr->queue_limit[TIPC_HIGH_IMPORTANCE + 4] = 900;
2408         l_ptr->queue_limit[TIPC_CRITICAL_IMPORTANCE + 4] = 1200;
2409         l_ptr->queue_limit[CONN_MANAGER] = 1200;
2410         l_ptr->queue_limit[CHANGEOVER_PROTOCOL] = 2500;
2411         l_ptr->queue_limit[NAME_DISTRIBUTOR] = 3000;
2412         /* FRAGMENT and LAST_FRAGMENT packets */
2413         l_ptr->queue_limit[MSG_FRAGMENTER] = 4000;
2414 }
2415
2416 /**
2417  * link_find_link - locate link by name
2418  * @name: ptr to link name string
2419  * @node: ptr to area to be filled with ptr to associated node
2420  *
2421  * Caller must hold 'tipc_net_lock' to ensure node and bearer are not deleted;
2422  * this also prevents link deletion.
2423  *
2424  * Returns pointer to link (or 0 if invalid link name).
2425  */
2426 static struct tipc_link *link_find_link(const char *name,
2427                                         struct tipc_node **node)
2428 {
2429         struct tipc_link *l_ptr;
2430         struct tipc_node *n_ptr;
2431         int i;
2432
2433         list_for_each_entry(n_ptr, &tipc_node_list, list) {
2434                 for (i = 0; i < MAX_BEARERS; i++) {
2435                         l_ptr = n_ptr->links[i];
2436                         if (l_ptr && !strcmp(l_ptr->name, name))
2437                                 goto found;
2438                 }
2439         }
2440         l_ptr = NULL;
2441         n_ptr = NULL;
2442 found:
2443         *node = n_ptr;
2444         return l_ptr;
2445 }
2446
2447 /**
2448  * link_value_is_valid -- validate proposed link tolerance/priority/window
2449  *
2450  * @cmd: value type (TIPC_CMD_SET_LINK_*)
2451  * @new_value: the new value
2452  *
2453  * Returns 1 if value is within range, 0 if not.
2454  */
2455 static int link_value_is_valid(u16 cmd, u32 new_value)
2456 {
2457         switch (cmd) {
2458         case TIPC_CMD_SET_LINK_TOL:
2459                 return (new_value >= TIPC_MIN_LINK_TOL) &&
2460                         (new_value <= TIPC_MAX_LINK_TOL);
2461         case TIPC_CMD_SET_LINK_PRI:
2462                 return (new_value <= TIPC_MAX_LINK_PRI);
2463         case TIPC_CMD_SET_LINK_WINDOW:
2464                 return (new_value >= TIPC_MIN_LINK_WIN) &&
2465                         (new_value <= TIPC_MAX_LINK_WIN);
2466         }
2467         return 0;
2468 }
2469
2470 /**
2471  * link_cmd_set_value - change priority/tolerance/window for link/bearer/media
2472  * @name: ptr to link, bearer, or media name
2473  * @new_value: new value of link, bearer, or media setting
2474  * @cmd: which link, bearer, or media attribute to set (TIPC_CMD_SET_LINK_*)
2475  *
2476  * Caller must hold 'tipc_net_lock' to ensure link/bearer/media is not deleted.
2477  *
2478  * Returns 0 if value updated and negative value on error.
2479  */
2480 static int link_cmd_set_value(const char *name, u32 new_value, u16 cmd)
2481 {
2482         struct tipc_node *node;
2483         struct tipc_link *l_ptr;
2484         struct tipc_bearer *b_ptr;
2485         struct tipc_media *m_ptr;
2486         int res = 0;
2487
2488         l_ptr = link_find_link(name, &node);
2489         if (l_ptr) {
2490                 /*
2491                  * acquire node lock for tipc_link_send_proto_msg().
2492                  * see "TIPC locking policy" in net.c.
2493                  */
2494                 tipc_node_lock(node);
2495                 switch (cmd) {
2496                 case TIPC_CMD_SET_LINK_TOL:
2497                         link_set_supervision_props(l_ptr, new_value);
2498                         tipc_link_send_proto_msg(l_ptr,
2499                                 STATE_MSG, 0, 0, new_value, 0, 0);
2500                         break;
2501                 case TIPC_CMD_SET_LINK_PRI:
2502                         l_ptr->priority = new_value;
2503                         tipc_link_send_proto_msg(l_ptr,
2504                                 STATE_MSG, 0, 0, 0, new_value, 0);
2505                         break;
2506                 case TIPC_CMD_SET_LINK_WINDOW:
2507                         tipc_link_set_queue_limits(l_ptr, new_value);
2508                         break;
2509                 default:
2510                         res = -EINVAL;
2511                         break;
2512                 }
2513                 tipc_node_unlock(node);
2514                 return res;
2515         }
2516
2517         b_ptr = tipc_bearer_find(name);
2518         if (b_ptr) {
2519                 switch (cmd) {
2520                 case TIPC_CMD_SET_LINK_TOL:
2521                         b_ptr->tolerance = new_value;
2522                         break;
2523                 case TIPC_CMD_SET_LINK_PRI:
2524                         b_ptr->priority = new_value;
2525                         break;
2526                 case TIPC_CMD_SET_LINK_WINDOW:
2527                         b_ptr->window = new_value;
2528                         break;
2529                 default:
2530                         res = -EINVAL;
2531                         break;
2532                 }
2533                 return res;
2534         }
2535
2536         m_ptr = tipc_media_find(name);
2537         if (!m_ptr)
2538                 return -ENODEV;
2539         switch (cmd) {
2540         case TIPC_CMD_SET_LINK_TOL:
2541                 m_ptr->tolerance = new_value;
2542                 break;
2543         case TIPC_CMD_SET_LINK_PRI:
2544                 m_ptr->priority = new_value;
2545                 break;
2546         case TIPC_CMD_SET_LINK_WINDOW:
2547                 m_ptr->window = new_value;
2548                 break;
2549         default:
2550                 res = -EINVAL;
2551                 break;
2552         }
2553         return res;
2554 }
2555
2556 struct sk_buff *tipc_link_cmd_config(const void *req_tlv_area, int req_tlv_space,
2557                                      u16 cmd)
2558 {
2559         struct tipc_link_config *args;
2560         u32 new_value;
2561         int res;
2562
2563         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_CONFIG))
2564                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2565
2566         args = (struct tipc_link_config *)TLV_DATA(req_tlv_area);
2567         new_value = ntohl(args->value);
2568
2569         if (!link_value_is_valid(cmd, new_value))
2570                 return tipc_cfg_reply_error_string(
2571                         "cannot change, value invalid");
2572
2573         if (!strcmp(args->name, tipc_bclink_name)) {
2574                 if ((cmd == TIPC_CMD_SET_LINK_WINDOW) &&
2575                     (tipc_bclink_set_queue_limits(new_value) == 0))
2576                         return tipc_cfg_reply_none();
2577                 return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
2578                                                    " (cannot change setting on broadcast link)");
2579         }
2580
2581         read_lock_bh(&tipc_net_lock);
2582         res = link_cmd_set_value(args->name, new_value, cmd);
2583         read_unlock_bh(&tipc_net_lock);
2584         if (res)
2585                 return tipc_cfg_reply_error_string("cannot change link setting");
2586
2587         return tipc_cfg_reply_none();
2588 }
2589
2590 /**
2591  * link_reset_statistics - reset link statistics
2592  * @l_ptr: pointer to link
2593  */
2594 static void link_reset_statistics(struct tipc_link *l_ptr)
2595 {
2596         memset(&l_ptr->stats, 0, sizeof(l_ptr->stats));
2597         l_ptr->stats.sent_info = l_ptr->next_out_no;
2598         l_ptr->stats.recv_info = l_ptr->next_in_no;
2599 }
2600
2601 struct sk_buff *tipc_link_cmd_reset_stats(const void *req_tlv_area, int req_tlv_space)
2602 {
2603         char *link_name;
2604         struct tipc_link *l_ptr;
2605         struct tipc_node *node;
2606
2607         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_NAME))
2608                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2609
2610         link_name = (char *)TLV_DATA(req_tlv_area);
2611         if (!strcmp(link_name, tipc_bclink_name)) {
2612                 if (tipc_bclink_reset_stats())
2613                         return tipc_cfg_reply_error_string("link not found");
2614                 return tipc_cfg_reply_none();
2615         }
2616
2617         read_lock_bh(&tipc_net_lock);
2618         l_ptr = link_find_link(link_name, &node);
2619         if (!l_ptr) {
2620                 read_unlock_bh(&tipc_net_lock);
2621                 return tipc_cfg_reply_error_string("link not found");
2622         }
2623
2624         tipc_node_lock(node);
2625         link_reset_statistics(l_ptr);
2626         tipc_node_unlock(node);
2627         read_unlock_bh(&tipc_net_lock);
2628         return tipc_cfg_reply_none();
2629 }
2630
2631 /**
2632  * percent - convert count to a percentage of total (rounding up or down)
2633  */
2634 static u32 percent(u32 count, u32 total)
2635 {
2636         return (count * 100 + (total / 2)) / total;
2637 }
2638
2639 /**
2640  * tipc_link_stats - print link statistics
2641  * @name: link name
2642  * @buf: print buffer area
2643  * @buf_size: size of print buffer area
2644  *
2645  * Returns length of print buffer data string (or 0 if error)
2646  */
2647 static int tipc_link_stats(const char *name, char *buf, const u32 buf_size)
2648 {
2649         struct tipc_link *l;
2650         struct tipc_stats *s;
2651         struct tipc_node *node;
2652         char *status;
2653         u32 profile_total = 0;
2654         int ret;
2655
2656         if (!strcmp(name, tipc_bclink_name))
2657                 return tipc_bclink_stats(buf, buf_size);
2658
2659         read_lock_bh(&tipc_net_lock);
2660         l = link_find_link(name, &node);
2661         if (!l) {
2662                 read_unlock_bh(&tipc_net_lock);
2663                 return 0;
2664         }
2665         tipc_node_lock(node);
2666         s = &l->stats;
2667
2668         if (tipc_link_is_active(l))
2669                 status = "ACTIVE";
2670         else if (tipc_link_is_up(l))
2671                 status = "STANDBY";
2672         else
2673                 status = "DEFUNCT";
2674
2675         ret = tipc_snprintf(buf, buf_size, "Link <%s>\n"
2676                             "  %s  MTU:%u  Priority:%u  Tolerance:%u ms"
2677                             "  Window:%u packets\n",
2678                             l->name, status, l->max_pkt, l->priority,
2679                             l->tolerance, l->queue_limit[0]);
2680
2681         ret += tipc_snprintf(buf + ret, buf_size - ret,
2682                              "  RX packets:%u fragments:%u/%u bundles:%u/%u\n",
2683                              l->next_in_no - s->recv_info, s->recv_fragments,
2684                              s->recv_fragmented, s->recv_bundles,
2685                              s->recv_bundled);
2686
2687         ret += tipc_snprintf(buf + ret, buf_size - ret,
2688                              "  TX packets:%u fragments:%u/%u bundles:%u/%u\n",
2689                              l->next_out_no - s->sent_info, s->sent_fragments,
2690                              s->sent_fragmented, s->sent_bundles,
2691                              s->sent_bundled);
2692
2693         profile_total = s->msg_length_counts;
2694         if (!profile_total)
2695                 profile_total = 1;
2696
2697         ret += tipc_snprintf(buf + ret, buf_size - ret,
2698                              "  TX profile sample:%u packets  average:%u octets\n"
2699                              "  0-64:%u%% -256:%u%% -1024:%u%% -4096:%u%% "
2700                              "-16384:%u%% -32768:%u%% -66000:%u%%\n",
2701                              s->msg_length_counts,
2702                              s->msg_lengths_total / profile_total,
2703                              percent(s->msg_length_profile[0], profile_total),
2704                              percent(s->msg_length_profile[1], profile_total),
2705                              percent(s->msg_length_profile[2], profile_total),
2706                              percent(s->msg_length_profile[3], profile_total),
2707                              percent(s->msg_length_profile[4], profile_total),
2708                              percent(s->msg_length_profile[5], profile_total),
2709                              percent(s->msg_length_profile[6], profile_total));
2710
2711         ret += tipc_snprintf(buf + ret, buf_size - ret,
2712                              "  RX states:%u probes:%u naks:%u defs:%u"
2713                              " dups:%u\n", s->recv_states, s->recv_probes,
2714                              s->recv_nacks, s->deferred_recv, s->duplicates);
2715
2716         ret += tipc_snprintf(buf + ret, buf_size - ret,
2717                              "  TX states:%u probes:%u naks:%u acks:%u"
2718                              " dups:%u\n", s->sent_states, s->sent_probes,
2719                              s->sent_nacks, s->sent_acks, s->retransmitted);
2720
2721         ret += tipc_snprintf(buf + ret, buf_size - ret,
2722                              "  Congestion link:%u  Send queue"
2723                              " max:%u avg:%u\n", s->link_congs,
2724                              s->max_queue_sz, s->queue_sz_counts ?
2725                              (s->accu_queue_sz / s->queue_sz_counts) : 0);
2726
2727         tipc_node_unlock(node);
2728         read_unlock_bh(&tipc_net_lock);
2729         return ret;
2730 }
2731
2732 struct sk_buff *tipc_link_cmd_show_stats(const void *req_tlv_area, int req_tlv_space)
2733 {
2734         struct sk_buff *buf;
2735         struct tlv_desc *rep_tlv;
2736         int str_len;
2737         int pb_len;
2738         char *pb;
2739
2740         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_NAME))
2741                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2742
2743         buf = tipc_cfg_reply_alloc(TLV_SPACE(ULTRA_STRING_MAX_LEN));
2744         if (!buf)
2745                 return NULL;
2746
2747         rep_tlv = (struct tlv_desc *)buf->data;
2748         pb = TLV_DATA(rep_tlv);
2749         pb_len = ULTRA_STRING_MAX_LEN;
2750         str_len = tipc_link_stats((char *)TLV_DATA(req_tlv_area),
2751                                   pb, pb_len);
2752         if (!str_len) {
2753                 kfree_skb(buf);
2754                 return tipc_cfg_reply_error_string("link not found");
2755         }
2756         str_len += 1;   /* for "\0" */
2757         skb_put(buf, TLV_SPACE(str_len));
2758         TLV_SET(rep_tlv, TIPC_TLV_ULTRA_STRING, NULL, str_len);
2759
2760         return buf;
2761 }
2762
2763 /**
2764  * tipc_link_get_max_pkt - get maximum packet size to use when sending to destination
2765  * @dest: network address of destination node
2766  * @selector: used to select from set of active links
2767  *
2768  * If no active link can be found, uses default maximum packet size.
2769  */
2770 u32 tipc_link_get_max_pkt(u32 dest, u32 selector)
2771 {
2772         struct tipc_node *n_ptr;
2773         struct tipc_link *l_ptr;
2774         u32 res = MAX_PKT_DEFAULT;
2775
2776         if (dest == tipc_own_addr)
2777                 return MAX_MSG_SIZE;
2778
2779         read_lock_bh(&tipc_net_lock);
2780         n_ptr = tipc_node_find(dest);
2781         if (n_ptr) {
2782                 tipc_node_lock(n_ptr);
2783                 l_ptr = n_ptr->active_links[selector & 1];
2784                 if (l_ptr)
2785                         res = l_ptr->max_pkt;
2786                 tipc_node_unlock(n_ptr);
2787         }
2788         read_unlock_bh(&tipc_net_lock);
2789         return res;
2790 }
2791
2792 static void link_print(struct tipc_link *l_ptr, const char *str)
2793 {
2794         pr_info("%s Link %x<%s>:", str, l_ptr->addr, l_ptr->b_ptr->name);
2795
2796         if (link_working_unknown(l_ptr))
2797                 pr_cont(":WU\n");
2798         else if (link_reset_reset(l_ptr))
2799                 pr_cont(":RR\n");
2800         else if (link_reset_unknown(l_ptr))
2801                 pr_cont(":RU\n");
2802         else if (link_working_working(l_ptr))
2803                 pr_cont(":WW\n");
2804         else
2805                 pr_cont("\n");
2806 }