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, 2010-2011, 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 /*
  45  * Error message prefixes
  46  */
  47 static const char *link_co_err = "Link changeover error, ";
  48 static const char *link_rst_msg = "Resetting link ";
  49 static const char *link_unk_evt = "Unknown link event ";
  50
  51 /*
  52  * Out-of-range value for link session numbers
  53  */
  54 #define INVALID_SESSION 0x10000
  55
  56 /*
  57  * Link state events:
  58  */
  59 #define  STARTING_EVT    856384768      /* link processing trigger */
  60 #define  TRAFFIC_MSG_EVT 560815u        /* rx'd ??? */
  61 #define  TIMEOUT_EVT     560817u        /* link timer expired */
  62
  63 /*
  64  * The following two 'message types' is really just implementation
  65  * data conveniently stored in the message header.
  66  * They must not be considered part of the protocol
  67  */
  68 #define OPEN_MSG   0
  69 #define CLOSED_MSG 1
  70
  71 /*
  72  * State value stored in 'exp_msg_count'
  73  */
  74 #define START_CHANGEOVER 100000u
  75
  76 /**
  77  * struct tipc_link_name - deconstructed link name
  78  * @addr_local: network address of node at this end
  79  * @if_local: name of interface at this end
  80  * @addr_peer: network address of node at far end
  81  * @if_peer: name of interface at far end
  82  */
  83 struct tipc_link_name {
  84         u32 addr_local;
  85         char if_local[TIPC_MAX_IF_NAME];
  86         u32 addr_peer;
  87         char if_peer[TIPC_MAX_IF_NAME];
  88 };
  89
  90 static void link_handle_out_of_seq_msg(struct tipc_link *l_ptr,
  91                                        struct sk_buff *buf);
  92 static void link_recv_proto_msg(struct tipc_link *l_ptr, struct sk_buff *buf);
  93 static int  link_recv_changeover_msg(struct tipc_link **l_ptr,
  94                                      struct sk_buff **buf);
  95 static void link_set_supervision_props(struct tipc_link *l_ptr, u32 tolerance);
  96 static int  link_send_sections_long(struct tipc_port *sender,
  97                                     struct iovec const *msg_sect,
  98                                     u32 num_sect, unsigned int total_len,
  99                                     u32 destnode);
 100 static void link_check_defragm_bufs(struct tipc_link *l_ptr);
 101 static void link_state_event(struct tipc_link *l_ptr, u32 event);
 102 static void link_reset_statistics(struct tipc_link *l_ptr);
 103 static void link_print(struct tipc_link *l_ptr, const char *str);
 104 static void link_start(struct tipc_link *l_ptr);
 105 static int link_send_long_buf(struct tipc_link *l_ptr, struct sk_buff *buf);
 106 static void tipc_link_send_sync(struct tipc_link *l);
 107 static void tipc_link_recv_sync(struct tipc_node *n, struct sk_buff *buf);
 108
 109 /*
 110  *  Simple link routines
 111  */
 112 static unsigned int align(unsigned int i)
 113 {
 114         return (i + 3) & ~3u;
 115 }
 116
 117 static void link_init_max_pkt(struct tipc_link *l_ptr)
 118 {
 119         u32 max_pkt;
 120
 121         max_pkt = (l_ptr->b_ptr->mtu & ~3);
 122         if (max_pkt > MAX_MSG_SIZE)
 123                 max_pkt = MAX_MSG_SIZE;
 124
 125         l_ptr->max_pkt_target = max_pkt;
 126         if (l_ptr->max_pkt_target < MAX_PKT_DEFAULT)
 127                 l_ptr->max_pkt = l_ptr->max_pkt_target;
 128         else
 129                 l_ptr->max_pkt = MAX_PKT_DEFAULT;
 130
 131         l_ptr->max_pkt_probes = 0;
 132 }
 133
 134 static u32 link_next_sent(struct tipc_link *l_ptr)
 135 {
 136         if (l_ptr->next_out)
 137                 return buf_seqno(l_ptr->next_out);
 138         return mod(l_ptr->next_out_no);
 139 }
 140
 141 static u32 link_last_sent(struct tipc_link *l_ptr)
 142 {
 143         return mod(link_next_sent(l_ptr) - 1);
 144 }
 145
 146 /*
 147  *  Simple non-static link routines (i.e. referenced outside this file)
 148  */
 149 int tipc_link_is_up(struct tipc_link *l_ptr)
 150 {
 151         if (!l_ptr)
 152                 return 0;
 153         return link_working_working(l_ptr) || link_working_unknown(l_ptr);
 154 }
 155
 156 int tipc_link_is_active(struct tipc_link *l_ptr)
 157 {
 158         return  (l_ptr->owner->active_links[0] == l_ptr) ||
 159                 (l_ptr->owner->active_links[1] == l_ptr);
 160 }
 161
 162 /**
 163  * link_name_validate - validate & (optionally) deconstruct tipc_link name
 164  * @name: ptr to link name string
 165  * @name_parts: ptr to area for link name components (or NULL if not needed)
 166  *
 167  * Returns 1 if link name is valid, otherwise 0.
 168  */
 169 static int link_name_validate(const char *name,
 170                                 struct tipc_link_name *name_parts)
 171 {
 172         char name_copy[TIPC_MAX_LINK_NAME];
 173         char *addr_local;
 174         char *if_local;
 175         char *addr_peer;
 176         char *if_peer;
 177         char dummy;
 178         u32 z_local, c_local, n_local;
 179         u32 z_peer, c_peer, n_peer;
 180         u32 if_local_len;
 181         u32 if_peer_len;
 182
 183         /* copy link name & ensure length is OK */
 184         name_copy[TIPC_MAX_LINK_NAME - 1] = 0;
 185         /* need above in case non-Posix strncpy() doesn't pad with nulls */
 186         strncpy(name_copy, name, TIPC_MAX_LINK_NAME);
 187         if (name_copy[TIPC_MAX_LINK_NAME - 1] != 0)
 188                 return 0;
 189
 190         /* ensure all component parts of link name are present */
 191         addr_local = name_copy;
 192         if_local = strchr(addr_local, ':');
 193         if (if_local == NULL)
 194                 return 0;
 195         *(if_local++) = 0;
 196         addr_peer = strchr(if_local, '-');
 197         if (addr_peer == NULL)
 198                 return 0;
 199         *(addr_peer++) = 0;
 200         if_local_len = addr_peer - if_local;
 201         if_peer = strchr(addr_peer, ':');
 202         if (if_peer == NULL)
 203                 return 0;
 204         *(if_peer++) = 0;
 205         if_peer_len = strlen(if_peer) + 1;
 206
 207         /* validate component parts of link name */
 208         if ((sscanf(addr_local, "%u.%u.%u%c",
 209                     &z_local, &c_local, &n_local, &dummy) != 3) ||
 210             (sscanf(addr_peer, "%u.%u.%u%c",
 211                     &z_peer, &c_peer, &n_peer, &dummy) != 3) ||
 212             (z_local > 255) || (c_local > 4095) || (n_local > 4095) ||
 213             (z_peer  > 255) || (c_peer  > 4095) || (n_peer  > 4095) ||
 214             (if_local_len <= 1) || (if_local_len > TIPC_MAX_IF_NAME) ||
 215             (if_peer_len  <= 1) || (if_peer_len  > TIPC_MAX_IF_NAME))
 216                 return 0;
 217
 218         /* return link name components, if necessary */
 219         if (name_parts) {
 220                 name_parts->addr_local = tipc_addr(z_local, c_local, n_local);
 221                 strcpy(name_parts->if_local, if_local);
 222                 name_parts->addr_peer = tipc_addr(z_peer, c_peer, n_peer);
 223                 strcpy(name_parts->if_peer, if_peer);
 224         }
 225         return 1;
 226 }
 227
 228 /**
 229  * link_timeout - handle expiration of link timer
 230  * @l_ptr: pointer to link
 231  *
 232  * This routine must not grab "tipc_net_lock" to avoid a potential deadlock conflict
 233  * with tipc_link_delete().  (There is no risk that the node will be deleted by
 234  * another thread because tipc_link_delete() always cancels the link timer before
 235  * tipc_node_delete() is called.)
 236  */
 237 static void link_timeout(struct tipc_link *l_ptr)
 238 {
 239         tipc_node_lock(l_ptr->owner);
 240
 241         /* update counters used in statistical profiling of send traffic */
 242         l_ptr->stats.accu_queue_sz += l_ptr->out_queue_size;
 243         l_ptr->stats.queue_sz_counts++;
 244
 245         if (l_ptr->first_out) {
 246                 struct tipc_msg *msg = buf_msg(l_ptr->first_out);
 247                 u32 length = msg_size(msg);
 248
 249                 if ((msg_user(msg) == MSG_FRAGMENTER) &&
 250                     (msg_type(msg) == FIRST_FRAGMENT)) {
 251                         length = msg_size(msg_get_wrapped(msg));
 252                 }
 253                 if (length) {
 254                         l_ptr->stats.msg_lengths_total += length;
 255                         l_ptr->stats.msg_length_counts++;
 256                         if (length <= 64)
 257                                 l_ptr->stats.msg_length_profile[0]++;
 258                         else if (length <= 256)
 259                                 l_ptr->stats.msg_length_profile[1]++;
 260                         else if (length <= 1024)
 261                                 l_ptr->stats.msg_length_profile[2]++;
 262                         else if (length <= 4096)
 263                                 l_ptr->stats.msg_length_profile[3]++;
 264                         else if (length <= 16384)
 265                                 l_ptr->stats.msg_length_profile[4]++;
 266                         else if (length <= 32768)
 267                                 l_ptr->stats.msg_length_profile[5]++;
 268                         else
 269                                 l_ptr->stats.msg_length_profile[6]++;
 270                 }
 271         }
 272
 273         /* do all other link processing performed on a periodic basis */
 274         link_check_defragm_bufs(l_ptr);
 275
 276         link_state_event(l_ptr, TIMEOUT_EVT);
 277
 278         if (l_ptr->next_out)
 279                 tipc_link_push_queue(l_ptr);
 280
 281         tipc_node_unlock(l_ptr->owner);
 282 }
 283
 284 static void link_set_timer(struct tipc_link *l_ptr, u32 time)
 285 {
 286         k_start_timer(&l_ptr->timer, time);
 287 }
 288
 289 /**
 290  * tipc_link_create - create a new link
 291  * @n_ptr: pointer to associated node
 292  * @b_ptr: pointer to associated bearer
 293  * @media_addr: media address to use when sending messages over link
 294  *
 295  * Returns pointer to link.
 296  */
 297 struct tipc_link *tipc_link_create(struct tipc_node *n_ptr,
 298                               struct tipc_bearer *b_ptr,
 299                               const struct tipc_media_addr *media_addr)
 300 {
 301         struct tipc_link *l_ptr;
 302         struct tipc_msg *msg;
 303         char *if_name;
 304         char addr_string[16];
 305         u32 peer = n_ptr->addr;
 306
 307         if (n_ptr->link_cnt >= 2) {
 308                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 309                 pr_err("Attempt to establish third link to %s\n", addr_string);
 310                 return NULL;
 311         }
 312
 313         if (n_ptr->links[b_ptr->identity]) {
 314                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 315                 pr_err("Attempt to establish second link on <%s> to %s\n",
 316                        b_ptr->name, addr_string);
 317                 return NULL;
 318         }
 319
 320         l_ptr = kzalloc(sizeof(*l_ptr), GFP_ATOMIC);
 321         if (!l_ptr) {
 322                 pr_warn("Link creation failed, no memory\n");
 323                 return NULL;
 324         }
 325
 326         l_ptr->addr = peer;
 327         if_name = strchr(b_ptr->name, ':') + 1;
 328         sprintf(l_ptr->name, "%u.%u.%u:%s-%u.%u.%u:unknown",
 329                 tipc_zone(tipc_own_addr), tipc_cluster(tipc_own_addr),
 330                 tipc_node(tipc_own_addr),
 331                 if_name,
 332                 tipc_zone(peer), tipc_cluster(peer), tipc_node(peer));
 333                 /* note: peer i/f name is updated by reset/activate message */
 334         memcpy(&l_ptr->media_addr, media_addr, sizeof(*media_addr));
 335         l_ptr->owner = n_ptr;
 336         l_ptr->checkpoint = 1;
 337         l_ptr->peer_session = INVALID_SESSION;
 338         l_ptr->b_ptr = b_ptr;
 339         link_set_supervision_props(l_ptr, b_ptr->tolerance);
 340         l_ptr->state = RESET_UNKNOWN;
 341
 342         l_ptr->pmsg = (struct tipc_msg *)&l_ptr->proto_msg;
 343         msg = l_ptr->pmsg;
 344         tipc_msg_init(msg, LINK_PROTOCOL, RESET_MSG, INT_H_SIZE, l_ptr->addr);
 345         msg_set_size(msg, sizeof(l_ptr->proto_msg));
 346         msg_set_session(msg, (tipc_random & 0xffff));
 347         msg_set_bearer_id(msg, b_ptr->identity);
 348         strcpy((char *)msg_data(msg), if_name);
 349
 350         l_ptr->priority = b_ptr->priority;
 351         tipc_link_set_queue_limits(l_ptr, b_ptr->window);
 352
 353         link_init_max_pkt(l_ptr);
 354
 355         l_ptr->next_out_no = 1;
 356         INIT_LIST_HEAD(&l_ptr->waiting_ports);
 357
 358         link_reset_statistics(l_ptr);
 359
 360         tipc_node_attach_link(n_ptr, l_ptr);
 361
 362         k_init_timer(&l_ptr->timer, (Handler)link_timeout, (unsigned long)l_ptr);
 363         list_add_tail(&l_ptr->link_list, &b_ptr->links);
 364         tipc_k_signal((Handler)link_start, (unsigned long)l_ptr);
 365
 366         return l_ptr;
 367 }
 368
 369 /**
 370  * tipc_link_delete - delete a link
 371  * @l_ptr: pointer to link
 372  *
 373  * Note: 'tipc_net_lock' is write_locked, bearer is locked.
 374  * This routine must not grab the node lock until after link timer cancellation
 375  * to avoid a potential deadlock situation.
 376  */
 377 void tipc_link_delete(struct tipc_link *l_ptr)
 378 {
 379         if (!l_ptr) {
 380                 pr_err("Attempt to delete non-existent link\n");
 381                 return;
 382         }
 383
 384         k_cancel_timer(&l_ptr->timer);
 385
 386         tipc_node_lock(l_ptr->owner);
 387         tipc_link_reset(l_ptr);
 388         tipc_node_detach_link(l_ptr->owner, l_ptr);
 389         tipc_link_stop(l_ptr);
 390         list_del_init(&l_ptr->link_list);
 391         tipc_node_unlock(l_ptr->owner);
 392         k_term_timer(&l_ptr->timer);
 393         kfree(l_ptr);
 394 }
 395
 396 static void link_start(struct tipc_link *l_ptr)
 397 {
 398         tipc_node_lock(l_ptr->owner);
 399         link_state_event(l_ptr, STARTING_EVT);
 400         tipc_node_unlock(l_ptr->owner);
 401 }
 402
 403 /**
 404  * link_schedule_port - schedule port for deferred sending
 405  * @l_ptr: pointer to link
 406  * @origport: reference to sending port
 407  * @sz: amount of data to be sent
 408  *
 409  * Schedules port for renewed sending of messages after link congestion
 410  * has abated.
 411  */
 412 static int link_schedule_port(struct tipc_link *l_ptr, u32 origport, u32 sz)
 413 {
 414         struct tipc_port *p_ptr;
 415
 416         spin_lock_bh(&tipc_port_list_lock);
 417         p_ptr = tipc_port_lock(origport);
 418         if (p_ptr) {
 419                 if (!p_ptr->wakeup)
 420                         goto exit;
 421                 if (!list_empty(&p_ptr->wait_list))
 422                         goto exit;
 423                 p_ptr->congested = 1;
 424                 p_ptr->waiting_pkts = 1 + ((sz - 1) / l_ptr->max_pkt);
 425                 list_add_tail(&p_ptr->wait_list, &l_ptr->waiting_ports);
 426                 l_ptr->stats.link_congs++;
 427 exit:
 428                 tipc_port_unlock(p_ptr);
 429         }
 430         spin_unlock_bh(&tipc_port_list_lock);
 431         return -ELINKCONG;
 432 }
 433
 434 void tipc_link_wakeup_ports(struct tipc_link *l_ptr, int all)
 435 {
 436         struct tipc_port *p_ptr;
 437         struct tipc_port *temp_p_ptr;
 438         int win = l_ptr->queue_limit[0] - l_ptr->out_queue_size;
 439
 440         if (all)
 441                 win = 100000;
 442         if (win <= 0)
 443                 return;
 444         if (!spin_trylock_bh(&tipc_port_list_lock))
 445                 return;
 446         if (link_congested(l_ptr))
 447                 goto exit;
 448         list_for_each_entry_safe(p_ptr, temp_p_ptr, &l_ptr->waiting_ports,
 449                                  wait_list) {
 450                 if (win <= 0)
 451                         break;
 452                 list_del_init(&p_ptr->wait_list);
 453                 spin_lock_bh(p_ptr->lock);
 454                 p_ptr->congested = 0;
 455                 p_ptr->wakeup(p_ptr);
 456                 win -= p_ptr->waiting_pkts;
 457                 spin_unlock_bh(p_ptr->lock);
 458         }
 459
 460 exit:
 461         spin_unlock_bh(&tipc_port_list_lock);
 462 }
 463
 464 /**
 465  * link_release_outqueue - purge link's outbound message queue
 466  * @l_ptr: pointer to link
 467  */
 468 static void link_release_outqueue(struct tipc_link *l_ptr)
 469 {
 470         struct sk_buff *buf = l_ptr->first_out;
 471         struct sk_buff *next;
 472
 473         while (buf) {
 474                 next = buf->next;
 475                 kfree_skb(buf);
 476                 buf = next;
 477         }
 478         l_ptr->first_out = NULL;
 479         l_ptr->out_queue_size = 0;
 480 }
 481
 482 /**
 483  * tipc_link_reset_fragments - purge link's inbound message fragments queue
 484  * @l_ptr: pointer to link
 485  */
 486 void tipc_link_reset_fragments(struct tipc_link *l_ptr)
 487 {
 488         struct sk_buff *buf = l_ptr->defragm_buf;
 489         struct sk_buff *next;
 490
 491         while (buf) {
 492                 next = buf->next;
 493                 kfree_skb(buf);
 494                 buf = next;
 495         }
 496         l_ptr->defragm_buf = NULL;
 497 }
 498
 499 /**
 500  * tipc_link_stop - purge all inbound and outbound messages associated with link
 501  * @l_ptr: pointer to link
 502  */
 503 void tipc_link_stop(struct tipc_link *l_ptr)
 504 {
 505         struct sk_buff *buf;
 506         struct sk_buff *next;
 507
 508         buf = l_ptr->oldest_deferred_in;
 509         while (buf) {
 510                 next = buf->next;
 511                 kfree_skb(buf);
 512                 buf = next;
 513         }
 514
 515         buf = l_ptr->first_out;
 516         while (buf) {
 517                 next = buf->next;
 518                 kfree_skb(buf);
 519                 buf = next;
 520         }
 521
 522         tipc_link_reset_fragments(l_ptr);
 523
 524         kfree_skb(l_ptr->proto_msg_queue);
 525         l_ptr->proto_msg_queue = NULL;
 526 }
 527
 528 void tipc_link_reset(struct tipc_link *l_ptr)
 529 {
 530         struct sk_buff *buf;
 531         u32 prev_state = l_ptr->state;
 532         u32 checkpoint = l_ptr->next_in_no;
 533         int was_active_link = tipc_link_is_active(l_ptr);
 534
 535         msg_set_session(l_ptr->pmsg, ((msg_session(l_ptr->pmsg) + 1) & 0xffff));
 536
 537         /* Link is down, accept any session */
 538         l_ptr->peer_session = INVALID_SESSION;
 539
 540         /* Prepare for max packet size negotiation */
 541         link_init_max_pkt(l_ptr);
 542
 543         l_ptr->state = RESET_UNKNOWN;
 544
 545         if ((prev_state == RESET_UNKNOWN) || (prev_state == RESET_RESET))
 546                 return;
 547
 548         tipc_node_link_down(l_ptr->owner, l_ptr);
 549         tipc_bearer_remove_dest(l_ptr->b_ptr, l_ptr->addr);
 550
 551         if (was_active_link && tipc_node_active_links(l_ptr->owner) &&
 552             l_ptr->owner->permit_changeover) {
 553                 l_ptr->reset_checkpoint = checkpoint;
 554                 l_ptr->exp_msg_count = START_CHANGEOVER;
 555         }
 556
 557         /* Clean up all queues: */
 558         link_release_outqueue(l_ptr);
 559         kfree_skb(l_ptr->proto_msg_queue);
 560         l_ptr->proto_msg_queue = NULL;
 561         buf = l_ptr->oldest_deferred_in;
 562         while (buf) {
 563                 struct sk_buff *next = buf->next;
 564                 kfree_skb(buf);
 565                 buf = next;
 566         }
 567         if (!list_empty(&l_ptr->waiting_ports))
 568                 tipc_link_wakeup_ports(l_ptr, 1);
 569
 570         l_ptr->retransm_queue_head = 0;
 571         l_ptr->retransm_queue_size = 0;
 572         l_ptr->last_out = NULL;
 573         l_ptr->first_out = NULL;
 574         l_ptr->next_out = NULL;
 575         l_ptr->unacked_window = 0;
 576         l_ptr->checkpoint = 1;
 577         l_ptr->next_out_no = 1;
 578         l_ptr->deferred_inqueue_sz = 0;
 579         l_ptr->oldest_deferred_in = NULL;
 580         l_ptr->newest_deferred_in = NULL;
 581         l_ptr->fsm_msg_cnt = 0;
 582         l_ptr->stale_count = 0;
 583         link_reset_statistics(l_ptr);
 584 }
 585
 586
 587 static void link_activate(struct tipc_link *l_ptr)
 588 {
 589         l_ptr->next_in_no = l_ptr->stats.recv_info = 1;
 590         tipc_node_link_up(l_ptr->owner, l_ptr);
 591         tipc_bearer_add_dest(l_ptr->b_ptr, l_ptr->addr);
 592 }
 593
 594 /**
 595  * link_state_event - link finite state machine
 596  * @l_ptr: pointer to link
 597  * @event: state machine event to process
 598  */
 599 static void link_state_event(struct tipc_link *l_ptr, unsigned int event)
 600 {
 601         struct tipc_link *other;
 602         u32 cont_intv = l_ptr->continuity_interval;
 603
 604         if (!l_ptr->started && (event != STARTING_EVT))
 605                 return;         /* Not yet. */
 606
 607         if (link_blocked(l_ptr)) {
 608                 if (event == TIMEOUT_EVT)
 609                         link_set_timer(l_ptr, cont_intv);
 610                 return;   /* Changeover going on */
 611         }
 612
 613         switch (l_ptr->state) {
 614         case WORKING_WORKING:
 615                 switch (event) {
 616                 case TRAFFIC_MSG_EVT:
 617                 case ACTIVATE_MSG:
 618                         break;
 619                 case TIMEOUT_EVT:
 620                         if (l_ptr->next_in_no != l_ptr->checkpoint) {
 621                                 l_ptr->checkpoint = l_ptr->next_in_no;
 622                                 if (tipc_bclink_acks_missing(l_ptr->owner)) {
 623                                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
 624                                                                  0, 0, 0, 0, 0);
 625                                         l_ptr->fsm_msg_cnt++;
 626                                 } else if (l_ptr->max_pkt < l_ptr->max_pkt_target) {
 627                                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
 628                                                                  1, 0, 0, 0, 0);
 629                                         l_ptr->fsm_msg_cnt++;
 630                                 }
 631                                 link_set_timer(l_ptr, cont_intv);
 632                                 break;
 633                         }
 634                         l_ptr->state = WORKING_UNKNOWN;
 635                         l_ptr->fsm_msg_cnt = 0;
 636                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
 637                         l_ptr->fsm_msg_cnt++;
 638                         link_set_timer(l_ptr, cont_intv / 4);
 639                         break;
 640                 case RESET_MSG:
 641                         pr_info("%s<%s>, requested by peer\n", link_rst_msg,
 642                                 l_ptr->name);
 643                         tipc_link_reset(l_ptr);
 644                         l_ptr->state = RESET_RESET;
 645                         l_ptr->fsm_msg_cnt = 0;
 646                         tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
 647                         l_ptr->fsm_msg_cnt++;
 648                         link_set_timer(l_ptr, cont_intv);
 649                         break;
 650                 default:
 651                         pr_err("%s%u in WW state\n", link_unk_evt, event);
 652                 }
 653                 break;
 654         case WORKING_UNKNOWN:
 655                 switch (event) {
 656                 case TRAFFIC_MSG_EVT:
 657                 case ACTIVATE_MSG:
 658                         l_ptr->state = WORKING_WORKING;
 659                         l_ptr->fsm_msg_cnt = 0;
 660                         link_set_timer(l_ptr, cont_intv);
 661                         break;
 662                 case RESET_MSG:
 663                         pr_info("%s<%s>, requested by peer while probing\n",
 664                                 link_rst_msg, l_ptr->name);
 665                         tipc_link_reset(l_ptr);
 666                         l_ptr->state = RESET_RESET;
 667                         l_ptr->fsm_msg_cnt = 0;
 668                         tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
 669                         l_ptr->fsm_msg_cnt++;
 670                         link_set_timer(l_ptr, cont_intv);
 671                         break;
 672                 case TIMEOUT_EVT:
 673                         if (l_ptr->next_in_no != l_ptr->checkpoint) {
 674                                 l_ptr->state = WORKING_WORKING;
 675                                 l_ptr->fsm_msg_cnt = 0;
 676                                 l_ptr->checkpoint = l_ptr->next_in_no;
 677                                 if (tipc_bclink_acks_missing(l_ptr->owner)) {
 678                                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
 679                                                                  0, 0, 0, 0, 0);
 680                                         l_ptr->fsm_msg_cnt++;
 681                                 }
 682                                 link_set_timer(l_ptr, cont_intv);
 683                         } else if (l_ptr->fsm_msg_cnt < l_ptr->abort_limit) {
 684                                 tipc_link_send_proto_msg(l_ptr, STATE_MSG,
 685                                                          1, 0, 0, 0, 0);
 686                                 l_ptr->fsm_msg_cnt++;
 687                                 link_set_timer(l_ptr, cont_intv / 4);
 688                         } else {        /* Link has failed */
 689                                 pr_warn("%s<%s>, peer not responding\n",
 690                                         link_rst_msg, l_ptr->name);
 691                                 tipc_link_reset(l_ptr);
 692                                 l_ptr->state = RESET_UNKNOWN;
 693                                 l_ptr->fsm_msg_cnt = 0;
 694                                 tipc_link_send_proto_msg(l_ptr, RESET_MSG,
 695                                                          0, 0, 0, 0, 0);
 696                                 l_ptr->fsm_msg_cnt++;
 697                                 link_set_timer(l_ptr, cont_intv);
 698                         }
 699                         break;
 700                 default:
 701                         pr_err("%s%u in WU state\n", link_unk_evt, event);
 702                 }
 703                 break;
 704         case RESET_UNKNOWN:
 705                 switch (event) {
 706                 case TRAFFIC_MSG_EVT:
 707                         break;
 708                 case ACTIVATE_MSG:
 709                         other = l_ptr->owner->active_links[0];
 710                         if (other && link_working_unknown(other))
 711                                 break;
 712                         l_ptr->state = WORKING_WORKING;
 713                         l_ptr->fsm_msg_cnt = 0;
 714                         link_activate(l_ptr);
 715                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
 716                         l_ptr->fsm_msg_cnt++;
 717                         if (l_ptr->owner->working_links == 1)
 718                                 tipc_link_send_sync(l_ptr);
 719                         link_set_timer(l_ptr, cont_intv);
 720                         break;
 721                 case RESET_MSG:
 722                         l_ptr->state = RESET_RESET;
 723                         l_ptr->fsm_msg_cnt = 0;
 724                         tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 1, 0, 0, 0, 0);
 725                         l_ptr->fsm_msg_cnt++;
 726                         link_set_timer(l_ptr, cont_intv);
 727                         break;
 728                 case STARTING_EVT:
 729                         l_ptr->started = 1;
 730                         /* fall through */
 731                 case TIMEOUT_EVT:
 732                         tipc_link_send_proto_msg(l_ptr, RESET_MSG, 0, 0, 0, 0, 0);
 733                         l_ptr->fsm_msg_cnt++;
 734                         link_set_timer(l_ptr, cont_intv);
 735                         break;
 736                 default:
 737                         pr_err("%s%u in RU state\n", link_unk_evt, event);
 738                 }
 739                 break;
 740         case RESET_RESET:
 741                 switch (event) {
 742                 case TRAFFIC_MSG_EVT:
 743                 case ACTIVATE_MSG:
 744                         other = l_ptr->owner->active_links[0];
 745                         if (other && link_working_unknown(other))
 746                                 break;
 747                         l_ptr->state = WORKING_WORKING;
 748                         l_ptr->fsm_msg_cnt = 0;
 749                         link_activate(l_ptr);
 750                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
 751                         l_ptr->fsm_msg_cnt++;
 752                         if (l_ptr->owner->working_links == 1)
 753                                 tipc_link_send_sync(l_ptr);
 754                         link_set_timer(l_ptr, cont_intv);
 755                         break;
 756                 case RESET_MSG:
 757                         break;
 758                 case TIMEOUT_EVT:
 759                         tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
 760                         l_ptr->fsm_msg_cnt++;
 761                         link_set_timer(l_ptr, cont_intv);
 762                         break;
 763                 default:
 764                         pr_err("%s%u in RR state\n", link_unk_evt, event);
 765                 }
 766                 break;
 767         default:
 768                 pr_err("Unknown link state %u/%u\n", l_ptr->state, event);
 769         }
 770 }
 771
 772 /*
 773  * link_bundle_buf(): Append contents of a buffer to
 774  * the tail of an existing one.
 775  */
 776 static int link_bundle_buf(struct tipc_link *l_ptr,
 777                            struct sk_buff *bundler,
 778                            struct sk_buff *buf)
 779 {
 780         struct tipc_msg *bundler_msg = buf_msg(bundler);
 781         struct tipc_msg *msg = buf_msg(buf);
 782         u32 size = msg_size(msg);
 783         u32 bundle_size = msg_size(bundler_msg);
 784         u32 to_pos = align(bundle_size);
 785         u32 pad = to_pos - bundle_size;
 786
 787         if (msg_user(bundler_msg) != MSG_BUNDLER)
 788                 return 0;
 789         if (msg_type(bundler_msg) != OPEN_MSG)
 790                 return 0;
 791         if (skb_tailroom(bundler) < (pad + size))
 792                 return 0;
 793         if (l_ptr->max_pkt < (to_pos + size))
 794                 return 0;
 795
 796         skb_put(bundler, pad + size);
 797         skb_copy_to_linear_data_offset(bundler, to_pos, buf->data, size);
 798         msg_set_size(bundler_msg, to_pos + size);
 799         msg_set_msgcnt(bundler_msg, msg_msgcnt(bundler_msg) + 1);
 800         kfree_skb(buf);
 801         l_ptr->stats.sent_bundled++;
 802         return 1;
 803 }
 804
 805 static void link_add_to_outqueue(struct tipc_link *l_ptr,
 806                                  struct sk_buff *buf,
 807                                  struct tipc_msg *msg)
 808 {
 809         u32 ack = mod(l_ptr->next_in_no - 1);
 810         u32 seqno = mod(l_ptr->next_out_no++);
 811
 812         msg_set_word(msg, 2, ((ack << 16) | seqno));
 813         msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
 814         buf->next = NULL;
 815         if (l_ptr->first_out) {
 816                 l_ptr->last_out->next = buf;
 817                 l_ptr->last_out = buf;
 818         } else
 819                 l_ptr->first_out = l_ptr->last_out = buf;
 820
 821         l_ptr->out_queue_size++;
 822         if (l_ptr->out_queue_size > l_ptr->stats.max_queue_sz)
 823                 l_ptr->stats.max_queue_sz = l_ptr->out_queue_size;
 824 }
 825
 826 static void link_add_chain_to_outqueue(struct tipc_link *l_ptr,
 827                                        struct sk_buff *buf_chain,
 828                                        u32 long_msgno)
 829 {
 830         struct sk_buff *buf;
 831         struct tipc_msg *msg;
 832
 833         if (!l_ptr->next_out)
 834                 l_ptr->next_out = buf_chain;
 835         while (buf_chain) {
 836                 buf = buf_chain;
 837                 buf_chain = buf_chain->next;
 838
 839                 msg = buf_msg(buf);
 840                 msg_set_long_msgno(msg, long_msgno);
 841                 link_add_to_outqueue(l_ptr, buf, msg);
 842         }
 843 }
 844
 845 /*
 846  * tipc_link_send_buf() is the 'full path' for messages, called from
 847  * inside TIPC when the 'fast path' in tipc_send_buf
 848  * has failed, and from link_send()
 849  */
 850 int tipc_link_send_buf(struct tipc_link *l_ptr, struct sk_buff *buf)
 851 {
 852         struct tipc_msg *msg = buf_msg(buf);
 853         u32 size = msg_size(msg);
 854         u32 dsz = msg_data_sz(msg);
 855         u32 queue_size = l_ptr->out_queue_size;
 856         u32 imp = tipc_msg_tot_importance(msg);
 857         u32 queue_limit = l_ptr->queue_limit[imp];
 858         u32 max_packet = l_ptr->max_pkt;
 859
 860         /* Match msg importance against queue limits: */
 861         if (unlikely(queue_size >= queue_limit)) {
 862                 if (imp <= TIPC_CRITICAL_IMPORTANCE) {
 863                         link_schedule_port(l_ptr, msg_origport(msg), size);
 864                         kfree_skb(buf);
 865                         return -ELINKCONG;
 866                 }
 867                 kfree_skb(buf);
 868                 if (imp > CONN_MANAGER) {
 869                         pr_warn("%s<%s>, send queue full", link_rst_msg,
 870                                 l_ptr->name);
 871                         tipc_link_reset(l_ptr);
 872                 }
 873                 return dsz;
 874         }
 875
 876         /* Fragmentation needed ? */
 877         if (size > max_packet)
 878                 return link_send_long_buf(l_ptr, buf);
 879
 880         /* Packet can be queued or sent. */
 881         if (likely(!tipc_bearer_blocked(l_ptr->b_ptr) &&
 882                    !link_congested(l_ptr))) {
 883                 link_add_to_outqueue(l_ptr, buf, msg);
 884
 885                 tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr);
 886                 l_ptr->unacked_window = 0;
 887                 return dsz;
 888         }
 889         /* Congestion: can message be bundled ? */
 890         if ((msg_user(msg) != CHANGEOVER_PROTOCOL) &&
 891             (msg_user(msg) != MSG_FRAGMENTER)) {
 892
 893                 /* Try adding message to an existing bundle */
 894                 if (l_ptr->next_out &&
 895                     link_bundle_buf(l_ptr, l_ptr->last_out, buf))
 896                         return dsz;
 897
 898                 /* Try creating a new bundle */
 899                 if (size <= max_packet * 2 / 3) {
 900                         struct sk_buff *bundler = tipc_buf_acquire(max_packet);
 901                         struct tipc_msg bundler_hdr;
 902
 903                         if (bundler) {
 904                                 tipc_msg_init(&bundler_hdr, MSG_BUNDLER, OPEN_MSG,
 905                                          INT_H_SIZE, l_ptr->addr);
 906                                 skb_copy_to_linear_data(bundler, &bundler_hdr,
 907                                                         INT_H_SIZE);
 908                                 skb_trim(bundler, INT_H_SIZE);
 909                                 link_bundle_buf(l_ptr, bundler, buf);
 910                                 buf = bundler;
 911                                 msg = buf_msg(buf);
 912                                 l_ptr->stats.sent_bundles++;
 913                         }
 914                 }
 915         }
 916         if (!l_ptr->next_out)
 917                 l_ptr->next_out = buf;
 918         link_add_to_outqueue(l_ptr, buf, msg);
 919         return dsz;
 920 }
 921
 922 /*
 923  * tipc_link_send(): same as tipc_link_send_buf(), but the link to use has
 924  * not been selected yet, and the the owner node is not locked
 925  * Called by TIPC internal users, e.g. the name distributor
 926  */
 927 int tipc_link_send(struct sk_buff *buf, u32 dest, u32 selector)
 928 {
 929         struct tipc_link *l_ptr;
 930         struct tipc_node *n_ptr;
 931         int res = -ELINKCONG;
 932
 933         read_lock_bh(&tipc_net_lock);
 934         n_ptr = tipc_node_find(dest);
 935         if (n_ptr) {
 936                 tipc_node_lock(n_ptr);
 937                 l_ptr = n_ptr->active_links[selector & 1];
 938                 if (l_ptr)
 939                         res = tipc_link_send_buf(l_ptr, buf);
 940                 else
 941                         kfree_skb(buf);
 942                 tipc_node_unlock(n_ptr);
 943         } else {
 944                 kfree_skb(buf);
 945         }
 946         read_unlock_bh(&tipc_net_lock);
 947         return res;
 948 }
 949
 950 /*
 951  * tipc_link_send_sync - synchronize broadcast link endpoints.
 952  *
 953  * Give a newly added peer node the sequence number where it should
 954  * start receiving and acking broadcast packets.
 955  *
 956  * Called with node locked
 957  */
 958 static void tipc_link_send_sync(struct tipc_link *l)
 959 {
 960         struct sk_buff *buf;
 961         struct tipc_msg *msg;
 962
 963         buf = tipc_buf_acquire(INT_H_SIZE);
 964         if (!buf)
 965                 return;
 966
 967         msg = buf_msg(buf);
 968         tipc_msg_init(msg, BCAST_PROTOCOL, STATE_MSG, INT_H_SIZE, l->addr);
 969         msg_set_last_bcast(msg, l->owner->bclink.acked);
 970         link_add_chain_to_outqueue(l, buf, 0);
 971         tipc_link_push_queue(l);
 972 }
 973
 974 /*
 975  * tipc_link_recv_sync - synchronize broadcast link endpoints.
 976  * Receive the sequence number where we should start receiving and
 977  * acking broadcast packets from a newly added peer node, and open
 978  * up for reception of such packets.
 979  *
 980  * Called with node locked
 981  */
 982 static void tipc_link_recv_sync(struct tipc_node *n, struct sk_buff *buf)
 983 {
 984         struct tipc_msg *msg = buf_msg(buf);
 985
 986         n->bclink.last_sent = n->bclink.last_in = msg_last_bcast(msg);
 987         n->bclink.recv_permitted = true;
 988         kfree_skb(buf);
 989 }
 990
 991 /*
 992  * tipc_link_send_names - send name table entries to new neighbor
 993  *
 994  * Send routine for bulk delivery of name table messages when contact
 995  * with a new neighbor occurs. No link congestion checking is performed
 996  * because name table messages *must* be delivered. The messages must be
 997  * small enough not to require fragmentation.
 998  * Called without any locks held.
 999  */
1000 void tipc_link_send_names(struct list_head *message_list, u32 dest)
1001 {
1002         struct tipc_node *n_ptr;
1003         struct tipc_link *l_ptr;
1004         struct sk_buff *buf;
1005         struct sk_buff *temp_buf;
1006
1007         if (list_empty(message_list))
1008                 return;
1009
1010         read_lock_bh(&tipc_net_lock);
1011         n_ptr = tipc_node_find(dest);
1012         if (n_ptr) {
1013                 tipc_node_lock(n_ptr);
1014                 l_ptr = n_ptr->active_links[0];
1015                 if (l_ptr) {
1016                         /* convert circular list to linear list */
1017                         ((struct sk_buff *)message_list->prev)->next = NULL;
1018                         link_add_chain_to_outqueue(l_ptr,
1019                                 (struct sk_buff *)message_list->next, 0);
1020                         tipc_link_push_queue(l_ptr);
1021                         INIT_LIST_HEAD(message_list);
1022                 }
1023                 tipc_node_unlock(n_ptr);
1024         }
1025         read_unlock_bh(&tipc_net_lock);
1026
1027         /* discard the messages if they couldn't be sent */
1028         list_for_each_safe(buf, temp_buf, ((struct sk_buff *)message_list)) {
1029                 list_del((struct list_head *)buf);
1030                 kfree_skb(buf);
1031         }
1032 }
1033
1034 /*
1035  * link_send_buf_fast: Entry for data messages where the
1036  * destination link is known and the header is complete,
1037  * inclusive total message length. Very time critical.
1038  * Link is locked. Returns user data length.
1039  */
1040 static int link_send_buf_fast(struct tipc_link *l_ptr, struct sk_buff *buf,
1041                               u32 *used_max_pkt)
1042 {
1043         struct tipc_msg *msg = buf_msg(buf);
1044         int res = msg_data_sz(msg);
1045
1046         if (likely(!link_congested(l_ptr))) {
1047                 if (likely(msg_size(msg) <= l_ptr->max_pkt)) {
1048                         if (likely(!tipc_bearer_blocked(l_ptr->b_ptr))) {
1049                                 link_add_to_outqueue(l_ptr, buf, msg);
1050                                 tipc_bearer_send(l_ptr->b_ptr, buf,
1051                                                  &l_ptr->media_addr);
1052                                 l_ptr->unacked_window = 0;
1053                                 return res;
1054                         }
1055                 } else
1056                         *used_max_pkt = l_ptr->max_pkt;
1057         }
1058         return tipc_link_send_buf(l_ptr, buf);  /* All other cases */
1059 }
1060
1061 /*
1062  * tipc_send_buf_fast: Entry for data messages where the
1063  * destination node is known and the header is complete,
1064  * inclusive total message length.
1065  * Returns user data length.
1066  */
1067 int tipc_send_buf_fast(struct sk_buff *buf, u32 destnode)
1068 {
1069         struct tipc_link *l_ptr;
1070         struct tipc_node *n_ptr;
1071         int res;
1072         u32 selector = msg_origport(buf_msg(buf)) & 1;
1073         u32 dummy;
1074
1075         read_lock_bh(&tipc_net_lock);
1076         n_ptr = tipc_node_find(destnode);
1077         if (likely(n_ptr)) {
1078                 tipc_node_lock(n_ptr);
1079                 l_ptr = n_ptr->active_links[selector];
1080                 if (likely(l_ptr)) {
1081                         res = link_send_buf_fast(l_ptr, buf, &dummy);
1082                         tipc_node_unlock(n_ptr);
1083                         read_unlock_bh(&tipc_net_lock);
1084                         return res;
1085                 }
1086                 tipc_node_unlock(n_ptr);
1087         }
1088         read_unlock_bh(&tipc_net_lock);
1089         res = msg_data_sz(buf_msg(buf));
1090         tipc_reject_msg(buf, TIPC_ERR_NO_NODE);
1091         return res;
1092 }
1093
1094
1095 /*
1096  * tipc_link_send_sections_fast: Entry for messages where the
1097  * destination processor is known and the header is complete,
1098  * except for total message length.
1099  * Returns user data length or errno.
1100  */
1101 int tipc_link_send_sections_fast(struct tipc_port *sender,
1102                                  struct iovec const *msg_sect,
1103                                  const u32 num_sect,
1104                                  unsigned int total_len,
1105                                  u32 destaddr)
1106 {
1107         struct tipc_msg *hdr = &sender->phdr;
1108         struct tipc_link *l_ptr;
1109         struct sk_buff *buf;
1110         struct tipc_node *node;
1111         int res;
1112         u32 selector = msg_origport(hdr) & 1;
1113
1114 again:
1115         /*
1116          * Try building message using port's max_pkt hint.
1117          * (Must not hold any locks while building message.)
1118          */
1119         res = tipc_msg_build(hdr, msg_sect, num_sect, total_len,
1120                              sender->max_pkt, !sender->user_port, &buf);
1121
1122         read_lock_bh(&tipc_net_lock);
1123         node = tipc_node_find(destaddr);
1124         if (likely(node)) {
1125                 tipc_node_lock(node);
1126                 l_ptr = node->active_links[selector];
1127                 if (likely(l_ptr)) {
1128                         if (likely(buf)) {
1129                                 res = link_send_buf_fast(l_ptr, buf,
1130                                                          &sender->max_pkt);
1131 exit:
1132                                 tipc_node_unlock(node);
1133                                 read_unlock_bh(&tipc_net_lock);
1134                                 return res;
1135                         }
1136
1137                         /* Exit if build request was invalid */
1138                         if (unlikely(res < 0))
1139                                 goto exit;
1140
1141                         /* Exit if link (or bearer) is congested */
1142                         if (link_congested(l_ptr) ||
1143                             tipc_bearer_blocked(l_ptr->b_ptr)) {
1144                                 res = link_schedule_port(l_ptr,
1145                                                          sender->ref, res);
1146                                 goto exit;
1147                         }
1148
1149                         /*
1150                          * Message size exceeds max_pkt hint; update hint,
1151                          * then re-try fast path or fragment the message
1152                          */
1153                         sender->max_pkt = l_ptr->max_pkt;
1154                         tipc_node_unlock(node);
1155                         read_unlock_bh(&tipc_net_lock);
1156
1157
1158                         if ((msg_hdr_sz(hdr) + res) <= sender->max_pkt)
1159                                 goto again;
1160
1161                         return link_send_sections_long(sender, msg_sect,
1162                                                        num_sect, total_len,
1163                                                        destaddr);
1164                 }
1165                 tipc_node_unlock(node);
1166         }
1167         read_unlock_bh(&tipc_net_lock);
1168
1169         /* Couldn't find a link to the destination node */
1170         if (buf)
1171                 return tipc_reject_msg(buf, TIPC_ERR_NO_NODE);
1172         if (res >= 0)
1173                 return tipc_port_reject_sections(sender, hdr, msg_sect, num_sect,
1174                                                  total_len, TIPC_ERR_NO_NODE);
1175         return res;
1176 }
1177
1178 /*
1179  * link_send_sections_long(): Entry for long messages where the
1180  * destination node is known and the header is complete,
1181  * inclusive total message length.
1182  * Link and bearer congestion status have been checked to be ok,
1183  * and are ignored if they change.
1184  *
1185  * Note that fragments do not use the full link MTU so that they won't have
1186  * to undergo refragmentation if link changeover causes them to be sent
1187  * over another link with an additional tunnel header added as prefix.
1188  * (Refragmentation will still occur if the other link has a smaller MTU.)
1189  *
1190  * Returns user data length or errno.
1191  */
1192 static int link_send_sections_long(struct tipc_port *sender,
1193                                    struct iovec const *msg_sect,
1194                                    u32 num_sect,
1195                                    unsigned int total_len,
1196                                    u32 destaddr)
1197 {
1198         struct tipc_link *l_ptr;
1199         struct tipc_node *node;
1200         struct tipc_msg *hdr = &sender->phdr;
1201         u32 dsz = total_len;
1202         u32 max_pkt, fragm_sz, rest;
1203         struct tipc_msg fragm_hdr;
1204         struct sk_buff *buf, *buf_chain, *prev;
1205         u32 fragm_crs, fragm_rest, hsz, sect_rest;
1206         const unchar *sect_crs;
1207         int curr_sect;
1208         u32 fragm_no;
1209
1210 again:
1211         fragm_no = 1;
1212         max_pkt = sender->max_pkt - INT_H_SIZE;
1213                 /* leave room for tunnel header in case of link changeover */
1214         fragm_sz = max_pkt - INT_H_SIZE;
1215                 /* leave room for fragmentation header in each fragment */
1216         rest = dsz;
1217         fragm_crs = 0;
1218         fragm_rest = 0;
1219         sect_rest = 0;
1220         sect_crs = NULL;
1221         curr_sect = -1;
1222
1223         /* Prepare reusable fragment header */
1224         tipc_msg_init(&fragm_hdr, MSG_FRAGMENTER, FIRST_FRAGMENT,
1225                  INT_H_SIZE, msg_destnode(hdr));
1226         msg_set_size(&fragm_hdr, max_pkt);
1227         msg_set_fragm_no(&fragm_hdr, 1);
1228
1229         /* Prepare header of first fragment */
1230         buf_chain = buf = tipc_buf_acquire(max_pkt);
1231         if (!buf)
1232                 return -ENOMEM;
1233         buf->next = NULL;
1234         skb_copy_to_linear_data(buf, &fragm_hdr, INT_H_SIZE);
1235         hsz = msg_hdr_sz(hdr);
1236         skb_copy_to_linear_data_offset(buf, INT_H_SIZE, hdr, hsz);
1237
1238         /* Chop up message */
1239         fragm_crs = INT_H_SIZE + hsz;
1240         fragm_rest = fragm_sz - hsz;
1241
1242         do {            /* For all sections */
1243                 u32 sz;
1244
1245                 if (!sect_rest) {
1246                         sect_rest = msg_sect[++curr_sect].iov_len;
1247                         sect_crs = (const unchar *)msg_sect[curr_sect].iov_base;
1248                 }
1249
1250                 if (sect_rest < fragm_rest)
1251                         sz = sect_rest;
1252                 else
1253                         sz = fragm_rest;
1254
1255                 if (likely(!sender->user_port)) {
1256                         if (copy_from_user(buf->data + fragm_crs, sect_crs, sz)) {
1257 error:
1258                                 for (; buf_chain; buf_chain = buf) {
1259                                         buf = buf_chain->next;
1260                                         kfree_skb(buf_chain);
1261                                 }
1262                                 return -EFAULT;
1263                         }
1264                 } else
1265                         skb_copy_to_linear_data_offset(buf, fragm_crs,
1266                                                        sect_crs, sz);
1267                 sect_crs += sz;
1268                 sect_rest -= sz;
1269                 fragm_crs += sz;
1270                 fragm_rest -= sz;
1271                 rest -= sz;
1272
1273                 if (!fragm_rest && rest) {
1274
1275                         /* Initiate new fragment: */
1276                         if (rest <= fragm_sz) {
1277                                 fragm_sz = rest;
1278                                 msg_set_type(&fragm_hdr, LAST_FRAGMENT);
1279                         } else {
1280                                 msg_set_type(&fragm_hdr, FRAGMENT);
1281                         }
1282                         msg_set_size(&fragm_hdr, fragm_sz + INT_H_SIZE);
1283                         msg_set_fragm_no(&fragm_hdr, ++fragm_no);
1284                         prev = buf;
1285                         buf = tipc_buf_acquire(fragm_sz + INT_H_SIZE);
1286                         if (!buf)
1287                                 goto error;
1288
1289                         buf->next = NULL;
1290                         prev->next = buf;
1291                         skb_copy_to_linear_data(buf, &fragm_hdr, INT_H_SIZE);
1292                         fragm_crs = INT_H_SIZE;
1293                         fragm_rest = fragm_sz;
1294                 }
1295         } while (rest > 0);
1296
1297         /*
1298          * Now we have a buffer chain. Select a link and check
1299          * that packet size is still OK
1300          */
1301         node = tipc_node_find(destaddr);
1302         if (likely(node)) {
1303                 tipc_node_lock(node);
1304                 l_ptr = node->active_links[sender->ref & 1];
1305                 if (!l_ptr) {
1306                         tipc_node_unlock(node);
1307                         goto reject;
1308                 }
1309                 if (l_ptr->max_pkt < max_pkt) {
1310                         sender->max_pkt = l_ptr->max_pkt;
1311                         tipc_node_unlock(node);
1312                         for (; buf_chain; buf_chain = buf) {
1313                                 buf = buf_chain->next;
1314                                 kfree_skb(buf_chain);
1315                         }
1316                         goto again;
1317                 }
1318         } else {
1319 reject:
1320                 for (; buf_chain; buf_chain = buf) {
1321                         buf = buf_chain->next;
1322                         kfree_skb(buf_chain);
1323                 }
1324                 return tipc_port_reject_sections(sender, hdr, msg_sect, num_sect,
1325                                                  total_len, TIPC_ERR_NO_NODE);
1326         }
1327
1328         /* Append chain of fragments to send queue & send them */
1329         l_ptr->long_msg_seq_no++;
1330         link_add_chain_to_outqueue(l_ptr, buf_chain, l_ptr->long_msg_seq_no);
1331         l_ptr->stats.sent_fragments += fragm_no;
1332         l_ptr->stats.sent_fragmented++;
1333         tipc_link_push_queue(l_ptr);
1334         tipc_node_unlock(node);
1335         return dsz;
1336 }
1337
1338 /*
1339  * tipc_link_push_packet: Push one unsent packet to the media
1340  */
1341 u32 tipc_link_push_packet(struct tipc_link *l_ptr)
1342 {
1343         struct sk_buff *buf = l_ptr->first_out;
1344         u32 r_q_size = l_ptr->retransm_queue_size;
1345         u32 r_q_head = l_ptr->retransm_queue_head;
1346
1347         /* Step to position where retransmission failed, if any,    */
1348         /* consider that buffers may have been released in meantime */
1349         if (r_q_size && buf) {
1350                 u32 last = lesser(mod(r_q_head + r_q_size),
1351                                   link_last_sent(l_ptr));
1352                 u32 first = buf_seqno(buf);
1353
1354                 while (buf && less(first, r_q_head)) {
1355                         first = mod(first + 1);
1356                         buf = buf->next;
1357                 }
1358                 l_ptr->retransm_queue_head = r_q_head = first;
1359                 l_ptr->retransm_queue_size = r_q_size = mod(last - first);
1360         }
1361
1362         /* Continue retransmission now, if there is anything: */
1363         if (r_q_size && buf) {
1364                 msg_set_ack(buf_msg(buf), mod(l_ptr->next_in_no - 1));
1365                 msg_set_bcast_ack(buf_msg(buf), l_ptr->owner->bclink.last_in);
1366                 tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr);
1367                 l_ptr->retransm_queue_head = mod(++r_q_head);
1368                 l_ptr->retransm_queue_size = --r_q_size;
1369                 l_ptr->stats.retransmitted++;
1370                 return 0;
1371         }
1372
1373         /* Send deferred protocol message, if any: */
1374         buf = l_ptr->proto_msg_queue;
1375         if (buf) {
1376                 msg_set_ack(buf_msg(buf), mod(l_ptr->next_in_no - 1));
1377                 msg_set_bcast_ack(buf_msg(buf), l_ptr->owner->bclink.last_in);
1378                 tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr);
1379                 l_ptr->unacked_window = 0;
1380                 kfree_skb(buf);
1381                 l_ptr->proto_msg_queue = NULL;
1382                 return 0;
1383         }
1384
1385         /* Send one deferred data message, if send window not full: */
1386         buf = l_ptr->next_out;
1387         if (buf) {
1388                 struct tipc_msg *msg = buf_msg(buf);
1389                 u32 next = msg_seqno(msg);
1390                 u32 first = buf_seqno(l_ptr->first_out);
1391
1392                 if (mod(next - first) < l_ptr->queue_limit[0]) {
1393                         msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1394                         msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1395                         tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr);
1396                         if (msg_user(msg) == MSG_BUNDLER)
1397                                 msg_set_type(msg, CLOSED_MSG);
1398                         l_ptr->next_out = buf->next;
1399                         return 0;
1400                 }
1401         }
1402         return 1;
1403 }
1404
1405 /*
1406  * push_queue(): push out the unsent messages of a link where
1407  *               congestion has abated. Node is locked
1408  */
1409 void tipc_link_push_queue(struct tipc_link *l_ptr)
1410 {
1411         u32 res;
1412
1413         if (tipc_bearer_blocked(l_ptr->b_ptr))
1414                 return;
1415
1416         do {
1417                 res = tipc_link_push_packet(l_ptr);
1418         } while (!res);
1419 }
1420
1421 static void link_reset_all(unsigned long addr)
1422 {
1423         struct tipc_node *n_ptr;
1424         char addr_string[16];
1425         u32 i;
1426
1427         read_lock_bh(&tipc_net_lock);
1428         n_ptr = tipc_node_find((u32)addr);
1429         if (!n_ptr) {
1430                 read_unlock_bh(&tipc_net_lock);
1431                 return; /* node no longer exists */
1432         }
1433
1434         tipc_node_lock(n_ptr);
1435
1436         pr_warn("Resetting all links to %s\n",
1437                 tipc_addr_string_fill(addr_string, n_ptr->addr));
1438
1439         for (i = 0; i < MAX_BEARERS; i++) {
1440                 if (n_ptr->links[i]) {
1441                         link_print(n_ptr->links[i], "Resetting link\n");
1442                         tipc_link_reset(n_ptr->links[i]);
1443                 }
1444         }
1445
1446         tipc_node_unlock(n_ptr);
1447         read_unlock_bh(&tipc_net_lock);
1448 }
1449
1450 static void link_retransmit_failure(struct tipc_link *l_ptr,
1451                                         struct sk_buff *buf)
1452 {
1453         struct tipc_msg *msg = buf_msg(buf);
1454
1455         pr_warn("Retransmission failure on link <%s>\n", l_ptr->name);
1456
1457         if (l_ptr->addr) {
1458                 /* Handle failure on standard link */
1459                 link_print(l_ptr, "Resetting link\n");
1460                 tipc_link_reset(l_ptr);
1461
1462         } else {
1463                 /* Handle failure on broadcast link */
1464                 struct tipc_node *n_ptr;
1465                 char addr_string[16];
1466
1467                 pr_info("Msg seq number: %u,  ", msg_seqno(msg));
1468                 pr_cont("Outstanding acks: %lu\n",
1469                         (unsigned long) TIPC_SKB_CB(buf)->handle);
1470
1471                 n_ptr = tipc_bclink_retransmit_to();
1472                 tipc_node_lock(n_ptr);
1473
1474                 tipc_addr_string_fill(addr_string, n_ptr->addr);
1475                 pr_info("Broadcast link info for %s\n", addr_string);
1476                 pr_info("Reception permitted: %d,  Acked: %u\n",
1477                         n_ptr->bclink.recv_permitted,
1478                         n_ptr->bclink.acked);
1479                 pr_info("Last in: %u,  Oos state: %u,  Last sent: %u\n",
1480                         n_ptr->bclink.last_in,
1481                         n_ptr->bclink.oos_state,
1482                         n_ptr->bclink.last_sent);
1483
1484                 tipc_k_signal((Handler)link_reset_all, (unsigned long)n_ptr->addr);
1485
1486                 tipc_node_unlock(n_ptr);
1487
1488                 l_ptr->stale_count = 0;
1489         }
1490 }
1491
1492 void tipc_link_retransmit(struct tipc_link *l_ptr, struct sk_buff *buf,
1493                           u32 retransmits)
1494 {
1495         struct tipc_msg *msg;
1496
1497         if (!buf)
1498                 return;
1499
1500         msg = buf_msg(buf);
1501
1502         if (tipc_bearer_blocked(l_ptr->b_ptr)) {
1503                 if (l_ptr->retransm_queue_size == 0) {
1504                         l_ptr->retransm_queue_head = msg_seqno(msg);
1505                         l_ptr->retransm_queue_size = retransmits;
1506                 } else {
1507                         pr_err("Unexpected retransmit on link %s (qsize=%d)\n",
1508                                l_ptr->name, l_ptr->retransm_queue_size);
1509                 }
1510                 return;
1511         } else {
1512                 /* Detect repeated retransmit failures on unblocked bearer */
1513                 if (l_ptr->last_retransmitted == msg_seqno(msg)) {
1514                         if (++l_ptr->stale_count > 100) {
1515                                 link_retransmit_failure(l_ptr, buf);
1516                                 return;
1517                         }
1518                 } else {
1519                         l_ptr->last_retransmitted = msg_seqno(msg);
1520                         l_ptr->stale_count = 1;
1521                 }
1522         }
1523
1524         while (retransmits && (buf != l_ptr->next_out) && buf) {
1525                 msg = buf_msg(buf);
1526                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1527                 msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1528                 tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr);
1529                 buf = buf->next;
1530                 retransmits--;
1531                 l_ptr->stats.retransmitted++;
1532         }
1533
1534         l_ptr->retransm_queue_head = l_ptr->retransm_queue_size = 0;
1535 }
1536
1537 /**
1538  * link_insert_deferred_queue - insert deferred messages back into receive chain
1539  */
1540 static struct sk_buff *link_insert_deferred_queue(struct tipc_link *l_ptr,
1541                                                   struct sk_buff *buf)
1542 {
1543         u32 seq_no;
1544
1545         if (l_ptr->oldest_deferred_in == NULL)
1546                 return buf;
1547
1548         seq_no = buf_seqno(l_ptr->oldest_deferred_in);
1549         if (seq_no == mod(l_ptr->next_in_no)) {
1550                 l_ptr->newest_deferred_in->next = buf;
1551                 buf = l_ptr->oldest_deferred_in;
1552                 l_ptr->oldest_deferred_in = NULL;
1553                 l_ptr->deferred_inqueue_sz = 0;
1554         }
1555         return buf;
1556 }
1557
1558 /**
1559  * link_recv_buf_validate - validate basic format of received message
1560  *
1561  * This routine ensures a TIPC message has an acceptable header, and at least
1562  * as much data as the header indicates it should.  The routine also ensures
1563  * that the entire message header is stored in the main fragment of the message
1564  * buffer, to simplify future access to message header fields.
1565  *
1566  * Note: Having extra info present in the message header or data areas is OK.
1567  * TIPC will ignore the excess, under the assumption that it is optional info
1568  * introduced by a later release of the protocol.
1569  */
1570 static int link_recv_buf_validate(struct sk_buff *buf)
1571 {
1572         static u32 min_data_hdr_size[8] = {
1573                 SHORT_H_SIZE, MCAST_H_SIZE, NAMED_H_SIZE, BASIC_H_SIZE,
1574                 MAX_H_SIZE, MAX_H_SIZE, MAX_H_SIZE, MAX_H_SIZE
1575                 };
1576
1577         struct tipc_msg *msg;
1578         u32 tipc_hdr[2];
1579         u32 size;
1580         u32 hdr_size;
1581         u32 min_hdr_size;
1582
1583         if (unlikely(buf->len < MIN_H_SIZE))
1584                 return 0;
1585
1586         msg = skb_header_pointer(buf, 0, sizeof(tipc_hdr), tipc_hdr);
1587         if (msg == NULL)
1588                 return 0;
1589
1590         if (unlikely(msg_version(msg) != TIPC_VERSION))
1591                 return 0;
1592
1593         size = msg_size(msg);
1594         hdr_size = msg_hdr_sz(msg);
1595         min_hdr_size = msg_isdata(msg) ?
1596                 min_data_hdr_size[msg_type(msg)] : INT_H_SIZE;
1597
1598         if (unlikely((hdr_size < min_hdr_size) ||
1599                      (size < hdr_size) ||
1600                      (buf->len < size) ||
1601                      (size - hdr_size > TIPC_MAX_USER_MSG_SIZE)))
1602                 return 0;
1603
1604         return pskb_may_pull(buf, hdr_size);
1605 }
1606
1607 /**
1608  * tipc_recv_msg - process TIPC messages arriving from off-node
1609  * @head: pointer to message buffer chain
1610  * @tb_ptr: pointer to bearer message arrived on
1611  *
1612  * Invoked with no locks held.  Bearer pointer must point to a valid bearer
1613  * structure (i.e. cannot be NULL), but bearer can be inactive.
1614  */
1615 void tipc_recv_msg(struct sk_buff *head, struct tipc_bearer *b_ptr)
1616 {
1617         read_lock_bh(&tipc_net_lock);
1618         while (head) {
1619                 struct tipc_node *n_ptr;
1620                 struct tipc_link *l_ptr;
1621                 struct sk_buff *crs;
1622                 struct sk_buff *buf = head;
1623                 struct tipc_msg *msg;
1624                 u32 seq_no;
1625                 u32 ackd;
1626                 u32 released = 0;
1627                 int type;
1628
1629                 head = head->next;
1630
1631                 /* Ensure bearer is still enabled */
1632                 if (unlikely(!b_ptr->active))
1633                         goto cont;
1634
1635                 /* Ensure message is well-formed */
1636                 if (unlikely(!link_recv_buf_validate(buf)))
1637                         goto cont;
1638
1639                 /* Ensure message data is a single contiguous unit */
1640                 if (unlikely(skb_linearize(buf)))
1641                         goto cont;
1642
1643                 /* Handle arrival of a non-unicast link message */
1644                 msg = buf_msg(buf);
1645
1646                 if (unlikely(msg_non_seq(msg))) {
1647                         if (msg_user(msg) ==  LINK_CONFIG)
1648                                 tipc_disc_recv_msg(buf, b_ptr);
1649                         else
1650                                 tipc_bclink_recv_pkt(buf);
1651                         continue;
1652                 }
1653
1654                 /* Discard unicast link messages destined for another node */
1655                 if (unlikely(!msg_short(msg) &&
1656                              (msg_destnode(msg) != tipc_own_addr)))
1657                         goto cont;
1658
1659                 /* Locate neighboring node that sent message */
1660                 n_ptr = tipc_node_find(msg_prevnode(msg));
1661                 if (unlikely(!n_ptr))
1662                         goto cont;
1663                 tipc_node_lock(n_ptr);
1664
1665                 /* Locate unicast link endpoint that should handle message */
1666                 l_ptr = n_ptr->links[b_ptr->identity];
1667                 if (unlikely(!l_ptr)) {
1668                         tipc_node_unlock(n_ptr);
1669                         goto cont;
1670                 }
1671
1672                 /* Verify that communication with node is currently allowed */
1673                 if ((n_ptr->block_setup & WAIT_PEER_DOWN) &&
1674                         msg_user(msg) == LINK_PROTOCOL &&
1675                         (msg_type(msg) == RESET_MSG ||
1676                                         msg_type(msg) == ACTIVATE_MSG) &&
1677                         !msg_redundant_link(msg))
1678                         n_ptr->block_setup &= ~WAIT_PEER_DOWN;
1679
1680                 if (n_ptr->block_setup) {
1681                         tipc_node_unlock(n_ptr);
1682                         goto cont;
1683                 }
1684
1685                 /* Validate message sequence number info */
1686                 seq_no = msg_seqno(msg);
1687                 ackd = msg_ack(msg);
1688
1689                 /* Release acked messages */
1690                 if (n_ptr->bclink.recv_permitted)
1691                         tipc_bclink_acknowledge(n_ptr, msg_bcast_ack(msg));
1692
1693                 crs = l_ptr->first_out;
1694                 while ((crs != l_ptr->next_out) &&
1695                        less_eq(buf_seqno(crs), ackd)) {
1696                         struct sk_buff *next = crs->next;
1697
1698                         kfree_skb(crs);
1699                         crs = next;
1700                         released++;
1701                 }
1702                 if (released) {
1703                         l_ptr->first_out = crs;
1704                         l_ptr->out_queue_size -= released;
1705                 }
1706
1707                 /* Try sending any messages link endpoint has pending */
1708                 if (unlikely(l_ptr->next_out))
1709                         tipc_link_push_queue(l_ptr);
1710                 if (unlikely(!list_empty(&l_ptr->waiting_ports)))
1711                         tipc_link_wakeup_ports(l_ptr, 0);
1712                 if (unlikely(++l_ptr->unacked_window >= TIPC_MIN_LINK_WIN)) {
1713                         l_ptr->stats.sent_acks++;
1714                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
1715                 }
1716
1717                 /* Now (finally!) process the incoming message */
1718 protocol_check:
1719                 if (likely(link_working_working(l_ptr))) {
1720                         if (likely(seq_no == mod(l_ptr->next_in_no))) {
1721                                 l_ptr->next_in_no++;
1722                                 if (unlikely(l_ptr->oldest_deferred_in))
1723                                         head = link_insert_deferred_queue(l_ptr,
1724                                                                           head);
1725 deliver:
1726                                 if (likely(msg_isdata(msg))) {
1727                                         tipc_node_unlock(n_ptr);
1728                                         tipc_port_recv_msg(buf);
1729                                         continue;
1730                                 }
1731                                 switch (msg_user(msg)) {
1732                                         int ret;
1733                                 case MSG_BUNDLER:
1734                                         l_ptr->stats.recv_bundles++;
1735                                         l_ptr->stats.recv_bundled +=
1736                                                 msg_msgcnt(msg);
1737                                         tipc_node_unlock(n_ptr);
1738                                         tipc_link_recv_bundle(buf);
1739                                         continue;
1740                                 case NAME_DISTRIBUTOR:
1741                                         n_ptr->bclink.recv_permitted = true;
1742                                         tipc_node_unlock(n_ptr);
1743                                         tipc_named_recv(buf);
1744                                         continue;
1745                                 case BCAST_PROTOCOL:
1746                                         tipc_link_recv_sync(n_ptr, buf);
1747                                         tipc_node_unlock(n_ptr);
1748                                         continue;
1749                                 case CONN_MANAGER:
1750                                         tipc_node_unlock(n_ptr);
1751                                         tipc_port_recv_proto_msg(buf);
1752                                         continue;
1753                                 case MSG_FRAGMENTER:
1754                                         l_ptr->stats.recv_fragments++;
1755                                         ret = tipc_link_recv_fragment(
1756                                                 &l_ptr->defragm_buf,
1757                                                 &buf, &msg);
1758                                         if (ret == 1) {
1759                                                 l_ptr->stats.recv_fragmented++;
1760                                                 goto deliver;
1761                                         }
1762                                         if (ret == -1)
1763                                                 l_ptr->next_in_no--;
1764                                         break;
1765                                 case CHANGEOVER_PROTOCOL:
1766                                         type = msg_type(msg);
1767                                         if (link_recv_changeover_msg(&l_ptr,
1768                                                                      &buf)) {
1769                                                 msg = buf_msg(buf);
1770                                                 seq_no = msg_seqno(msg);
1771                                                 if (type == ORIGINAL_MSG)
1772                                                         goto deliver;
1773                                                 goto protocol_check;
1774                                         }
1775                                         break;
1776                                 default:
1777                                         kfree_skb(buf);
1778                                         buf = NULL;
1779                                         break;
1780                                 }
1781                                 tipc_node_unlock(n_ptr);
1782                                 tipc_net_route_msg(buf);
1783                                 continue;
1784                         }
1785                         link_handle_out_of_seq_msg(l_ptr, buf);
1786                         head = link_insert_deferred_queue(l_ptr, head);
1787                         tipc_node_unlock(n_ptr);
1788                         continue;
1789                 }
1790
1791                 /* Link is not in state WORKING_WORKING */
1792                 if (msg_user(msg) == LINK_PROTOCOL) {
1793                         link_recv_proto_msg(l_ptr, buf);
1794                         head = link_insert_deferred_queue(l_ptr, head);
1795                         tipc_node_unlock(n_ptr);
1796                         continue;
1797                 }
1798
1799                 /* Traffic message. Conditionally activate link */
1800                 link_state_event(l_ptr, TRAFFIC_MSG_EVT);
1801
1802                 if (link_working_working(l_ptr)) {
1803                         /* Re-insert buffer in front of queue */
1804                         buf->next = head;
1805                         head = buf;
1806                         tipc_node_unlock(n_ptr);
1807                         continue;
1808                 }
1809                 tipc_node_unlock(n_ptr);
1810 cont:
1811                 kfree_skb(buf);
1812         }
1813         read_unlock_bh(&tipc_net_lock);
1814 }
1815
1816 /**
1817  * tipc_link_defer_pkt - Add out-of-sequence message to deferred reception queue
1818  *
1819  * Returns increase in queue length (i.e. 0 or 1)
1820  */
1821 u32 tipc_link_defer_pkt(struct sk_buff **head, struct sk_buff **tail,
1822                         struct sk_buff *buf)
1823 {
1824         struct sk_buff *queue_buf;
1825         struct sk_buff **prev;
1826         u32 seq_no = buf_seqno(buf);
1827
1828         buf->next = NULL;
1829
1830         /* Empty queue ? */
1831         if (*head == NULL) {
1832                 *head = *tail = buf;
1833                 return 1;
1834         }
1835
1836         /* Last ? */
1837         if (less(buf_seqno(*tail), seq_no)) {
1838                 (*tail)->next = buf;
1839                 *tail = buf;
1840                 return 1;
1841         }
1842
1843         /* Locate insertion point in queue, then insert; discard if duplicate */
1844         prev = head;
1845         queue_buf = *head;
1846         for (;;) {
1847                 u32 curr_seqno = buf_seqno(queue_buf);
1848
1849                 if (seq_no == curr_seqno) {
1850                         kfree_skb(buf);
1851                         return 0;
1852                 }
1853
1854                 if (less(seq_no, curr_seqno))
1855                         break;
1856
1857                 prev = &queue_buf->next;
1858                 queue_buf = queue_buf->next;
1859         }
1860
1861         buf->next = queue_buf;
1862         *prev = buf;
1863         return 1;
1864 }
1865
1866 /*
1867  * link_handle_out_of_seq_msg - handle arrival of out-of-sequence packet
1868  */
1869 static void link_handle_out_of_seq_msg(struct tipc_link *l_ptr,
1870                                        struct sk_buff *buf)
1871 {
1872         u32 seq_no = buf_seqno(buf);
1873
1874         if (likely(msg_user(buf_msg(buf)) == LINK_PROTOCOL)) {
1875                 link_recv_proto_msg(l_ptr, buf);
1876                 return;
1877         }
1878
1879         /* Record OOS packet arrival (force mismatch on next timeout) */
1880         l_ptr->checkpoint--;
1881
1882         /*
1883          * Discard packet if a duplicate; otherwise add it to deferred queue
1884          * and notify peer of gap as per protocol specification
1885          */
1886         if (less(seq_no, mod(l_ptr->next_in_no))) {
1887                 l_ptr->stats.duplicates++;
1888                 kfree_skb(buf);
1889                 return;
1890         }
1891
1892         if (tipc_link_defer_pkt(&l_ptr->oldest_deferred_in,
1893                                 &l_ptr->newest_deferred_in, buf)) {
1894                 l_ptr->deferred_inqueue_sz++;
1895                 l_ptr->stats.deferred_recv++;
1896                 if ((l_ptr->deferred_inqueue_sz % 16) == 1)
1897                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
1898         } else
1899                 l_ptr->stats.duplicates++;
1900 }
1901
1902 /*
1903  * Send protocol message to the other endpoint.
1904  */
1905 void tipc_link_send_proto_msg(struct tipc_link *l_ptr, u32 msg_typ,
1906                                 int probe_msg, u32 gap, u32 tolerance,
1907                                 u32 priority, u32 ack_mtu)
1908 {
1909         struct sk_buff *buf = NULL;
1910         struct tipc_msg *msg = l_ptr->pmsg;
1911         u32 msg_size = sizeof(l_ptr->proto_msg);
1912         int r_flag;
1913
1914         /* Discard any previous message that was deferred due to congestion */
1915         if (l_ptr->proto_msg_queue) {
1916                 kfree_skb(l_ptr->proto_msg_queue);
1917                 l_ptr->proto_msg_queue = NULL;
1918         }
1919
1920         if (link_blocked(l_ptr))
1921                 return;
1922
1923         /* Abort non-RESET send if communication with node is prohibited */
1924         if ((l_ptr->owner->block_setup) && (msg_typ != RESET_MSG))
1925                 return;
1926
1927         /* Create protocol message with "out-of-sequence" sequence number */
1928         msg_set_type(msg, msg_typ);
1929         msg_set_net_plane(msg, l_ptr->b_ptr->net_plane);
1930         msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1931         msg_set_last_bcast(msg, tipc_bclink_get_last_sent());
1932
1933         if (msg_typ == STATE_MSG) {
1934                 u32 next_sent = mod(l_ptr->next_out_no);
1935
1936                 if (!tipc_link_is_up(l_ptr))
1937                         return;
1938                 if (l_ptr->next_out)
1939                         next_sent = buf_seqno(l_ptr->next_out);
1940                 msg_set_next_sent(msg, next_sent);
1941                 if (l_ptr->oldest_deferred_in) {
1942                         u32 rec = buf_seqno(l_ptr->oldest_deferred_in);
1943                         gap = mod(rec - mod(l_ptr->next_in_no));
1944                 }
1945                 msg_set_seq_gap(msg, gap);
1946                 if (gap)
1947                         l_ptr->stats.sent_nacks++;
1948                 msg_set_link_tolerance(msg, tolerance);
1949                 msg_set_linkprio(msg, priority);
1950                 msg_set_max_pkt(msg, ack_mtu);
1951                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1952                 msg_set_probe(msg, probe_msg != 0);
1953                 if (probe_msg) {
1954                         u32 mtu = l_ptr->max_pkt;
1955
1956                         if ((mtu < l_ptr->max_pkt_target) &&
1957                             link_working_working(l_ptr) &&
1958                             l_ptr->fsm_msg_cnt) {
1959                                 msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
1960                                 if (l_ptr->max_pkt_probes == 10) {
1961                                         l_ptr->max_pkt_target = (msg_size - 4);
1962                                         l_ptr->max_pkt_probes = 0;
1963                                         msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
1964                                 }
1965                                 l_ptr->max_pkt_probes++;
1966                         }
1967
1968                         l_ptr->stats.sent_probes++;
1969                 }
1970                 l_ptr->stats.sent_states++;
1971         } else {                /* RESET_MSG or ACTIVATE_MSG */
1972                 msg_set_ack(msg, mod(l_ptr->reset_checkpoint - 1));
1973                 msg_set_seq_gap(msg, 0);
1974                 msg_set_next_sent(msg, 1);
1975                 msg_set_probe(msg, 0);
1976                 msg_set_link_tolerance(msg, l_ptr->tolerance);
1977                 msg_set_linkprio(msg, l_ptr->priority);
1978                 msg_set_max_pkt(msg, l_ptr->max_pkt_target);
1979         }
1980
1981         r_flag = (l_ptr->owner->working_links > tipc_link_is_up(l_ptr));
1982         msg_set_redundant_link(msg, r_flag);
1983         msg_set_linkprio(msg, l_ptr->priority);
1984         msg_set_size(msg, msg_size);
1985
1986         msg_set_seqno(msg, mod(l_ptr->next_out_no + (0xffff/2)));
1987
1988         buf = tipc_buf_acquire(msg_size);
1989         if (!buf)
1990                 return;
1991
1992         skb_copy_to_linear_data(buf, msg, sizeof(l_ptr->proto_msg));
1993
1994         /* Defer message if bearer is already blocked */
1995         if (tipc_bearer_blocked(l_ptr->b_ptr)) {
1996                 l_ptr->proto_msg_queue = buf;
1997                 return;
1998         }
1999
2000         tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr);
2001         l_ptr->unacked_window = 0;
2002         kfree_skb(buf);
2003 }
2004
2005 /*
2006  * Receive protocol message :
2007  * Note that network plane id propagates through the network, and may
2008  * change at any time. The node with lowest address rules
2009  */
2010 static void link_recv_proto_msg(struct tipc_link *l_ptr, struct sk_buff *buf)
2011 {
2012         u32 rec_gap = 0;
2013         u32 max_pkt_info;
2014         u32 max_pkt_ack;
2015         u32 msg_tol;
2016         struct tipc_msg *msg = buf_msg(buf);
2017
2018         if (link_blocked(l_ptr))
2019                 goto exit;
2020
2021         /* record unnumbered packet arrival (force mismatch on next timeout) */
2022         l_ptr->checkpoint--;
2023
2024         if (l_ptr->b_ptr->net_plane != msg_net_plane(msg))
2025                 if (tipc_own_addr > msg_prevnode(msg))
2026                         l_ptr->b_ptr->net_plane = msg_net_plane(msg);
2027
2028         l_ptr->owner->permit_changeover = msg_redundant_link(msg);
2029
2030         switch (msg_type(msg)) {
2031
2032         case RESET_MSG:
2033                 if (!link_working_unknown(l_ptr) &&
2034                     (l_ptr->peer_session != INVALID_SESSION)) {
2035                         if (less_eq(msg_session(msg), l_ptr->peer_session))
2036                                 break; /* duplicate or old reset: ignore */
2037                 }
2038
2039                 if (!msg_redundant_link(msg) && (link_working_working(l_ptr) ||
2040                                 link_working_unknown(l_ptr))) {
2041                         /*
2042                          * peer has lost contact -- don't allow peer's links
2043                          * to reactivate before we recognize loss & clean up
2044                          */
2045                         l_ptr->owner->block_setup = WAIT_NODE_DOWN;
2046                 }
2047
2048                 link_state_event(l_ptr, RESET_MSG);
2049
2050                 /* fall thru' */
2051         case ACTIVATE_MSG:
2052                 /* Update link settings according other endpoint's values */
2053                 strcpy((strrchr(l_ptr->name, ':') + 1), (char *)msg_data(msg));
2054
2055                 msg_tol = msg_link_tolerance(msg);
2056                 if (msg_tol > l_ptr->tolerance)
2057                         link_set_supervision_props(l_ptr, msg_tol);
2058
2059                 if (msg_linkprio(msg) > l_ptr->priority)
2060                         l_ptr->priority = msg_linkprio(msg);
2061
2062                 max_pkt_info = msg_max_pkt(msg);
2063                 if (max_pkt_info) {
2064                         if (max_pkt_info < l_ptr->max_pkt_target)
2065                                 l_ptr->max_pkt_target = max_pkt_info;
2066                         if (l_ptr->max_pkt > l_ptr->max_pkt_target)
2067                                 l_ptr->max_pkt = l_ptr->max_pkt_target;
2068                 } else {
2069                         l_ptr->max_pkt = l_ptr->max_pkt_target;
2070                 }
2071
2072                 /* Synchronize broadcast link info, if not done previously */
2073                 if (!tipc_node_is_up(l_ptr->owner)) {
2074                         l_ptr->owner->bclink.last_sent =
2075                                 l_ptr->owner->bclink.last_in =
2076                                 msg_last_bcast(msg);
2077                         l_ptr->owner->bclink.oos_state = 0;
2078                 }
2079
2080                 l_ptr->peer_session = msg_session(msg);
2081                 l_ptr->peer_bearer_id = msg_bearer_id(msg);
2082
2083                 if (msg_type(msg) == ACTIVATE_MSG)
2084                         link_state_event(l_ptr, ACTIVATE_MSG);
2085                 break;
2086         case STATE_MSG:
2087
2088                 msg_tol = msg_link_tolerance(msg);
2089                 if (msg_tol)
2090                         link_set_supervision_props(l_ptr, msg_tol);
2091
2092                 if (msg_linkprio(msg) &&
2093                     (msg_linkprio(msg) != l_ptr->priority)) {
2094                         pr_warn("%s<%s>, priority change %u->%u\n",
2095                                 link_rst_msg, l_ptr->name, l_ptr->priority,
2096                                 msg_linkprio(msg));
2097                         l_ptr->priority = msg_linkprio(msg);
2098                         tipc_link_reset(l_ptr); /* Enforce change to take effect */
2099                         break;
2100                 }
2101                 link_state_event(l_ptr, TRAFFIC_MSG_EVT);
2102                 l_ptr->stats.recv_states++;
2103                 if (link_reset_unknown(l_ptr))
2104                         break;
2105
2106                 if (less_eq(mod(l_ptr->next_in_no), msg_next_sent(msg))) {
2107                         rec_gap = mod(msg_next_sent(msg) -
2108                                       mod(l_ptr->next_in_no));
2109                 }
2110
2111                 max_pkt_ack = msg_max_pkt(msg);
2112                 if (max_pkt_ack > l_ptr->max_pkt) {
2113                         l_ptr->max_pkt = max_pkt_ack;
2114                         l_ptr->max_pkt_probes = 0;
2115                 }
2116
2117                 max_pkt_ack = 0;
2118                 if (msg_probe(msg)) {
2119                         l_ptr->stats.recv_probes++;
2120                         if (msg_size(msg) > sizeof(l_ptr->proto_msg))
2121                                 max_pkt_ack = msg_size(msg);
2122                 }
2123
2124                 /* Protocol message before retransmits, reduce loss risk */
2125                 if (l_ptr->owner->bclink.recv_permitted)
2126                         tipc_bclink_update_link_state(l_ptr->owner,
2127                                                       msg_last_bcast(msg));
2128
2129                 if (rec_gap || (msg_probe(msg))) {
2130                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
2131                                                  0, rec_gap, 0, 0, max_pkt_ack);
2132                 }
2133                 if (msg_seq_gap(msg)) {
2134                         l_ptr->stats.recv_nacks++;
2135                         tipc_link_retransmit(l_ptr, l_ptr->first_out,
2136                                              msg_seq_gap(msg));
2137                 }
2138                 break;
2139         }
2140 exit:
2141         kfree_skb(buf);
2142 }
2143
2144
2145 /*
2146  * tipc_link_tunnel(): Send one message via a link belonging to
2147  * another bearer. Owner node is locked.
2148  */
2149 static void tipc_link_tunnel(struct tipc_link *l_ptr,
2150                              struct tipc_msg *tunnel_hdr,
2151                              struct tipc_msg  *msg,
2152                              u32 selector)
2153 {
2154         struct tipc_link *tunnel;
2155         struct sk_buff *buf;
2156         u32 length = msg_size(msg);
2157
2158         tunnel = l_ptr->owner->active_links[selector & 1];
2159         if (!tipc_link_is_up(tunnel)) {
2160                 pr_warn("%stunnel link no longer available\n", link_co_err);
2161                 return;
2162         }
2163         msg_set_size(tunnel_hdr, length + INT_H_SIZE);
2164         buf = tipc_buf_acquire(length + INT_H_SIZE);
2165         if (!buf) {
2166                 pr_warn("%sunable to send tunnel msg\n", link_co_err);
2167                 return;
2168         }
2169         skb_copy_to_linear_data(buf, tunnel_hdr, INT_H_SIZE);
2170         skb_copy_to_linear_data_offset(buf, INT_H_SIZE, msg, length);
2171         tipc_link_send_buf(tunnel, buf);
2172 }
2173
2174
2175
2176 /*
2177  * changeover(): Send whole message queue via the remaining link
2178  *               Owner node is locked.
2179  */
2180 void tipc_link_changeover(struct tipc_link *l_ptr)
2181 {
2182         u32 msgcount = l_ptr->out_queue_size;
2183         struct sk_buff *crs = l_ptr->first_out;
2184         struct tipc_link *tunnel = l_ptr->owner->active_links[0];
2185         struct tipc_msg tunnel_hdr;
2186         int split_bundles;
2187
2188         if (!tunnel)
2189                 return;
2190
2191         if (!l_ptr->owner->permit_changeover) {
2192                 pr_warn("%speer did not permit changeover\n", link_co_err);
2193                 return;
2194         }
2195
2196         tipc_msg_init(&tunnel_hdr, CHANGEOVER_PROTOCOL,
2197                  ORIGINAL_MSG, INT_H_SIZE, l_ptr->addr);
2198         msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
2199         msg_set_msgcnt(&tunnel_hdr, msgcount);
2200
2201         if (!l_ptr->first_out) {
2202                 struct sk_buff *buf;
2203
2204                 buf = tipc_buf_acquire(INT_H_SIZE);
2205                 if (buf) {
2206                         skb_copy_to_linear_data(buf, &tunnel_hdr, INT_H_SIZE);
2207                         msg_set_size(&tunnel_hdr, INT_H_SIZE);
2208                         tipc_link_send_buf(tunnel, buf);
2209                 } else {
2210                         pr_warn("%sunable to send changeover msg\n",
2211                                 link_co_err);
2212                 }
2213                 return;
2214         }
2215
2216         split_bundles = (l_ptr->owner->active_links[0] !=
2217                          l_ptr->owner->active_links[1]);
2218
2219         while (crs) {
2220                 struct tipc_msg *msg = buf_msg(crs);
2221
2222                 if ((msg_user(msg) == MSG_BUNDLER) && split_bundles) {
2223                         struct tipc_msg *m = msg_get_wrapped(msg);
2224                         unchar *pos = (unchar *)m;
2225
2226                         msgcount = msg_msgcnt(msg);
2227                         while (msgcount--) {
2228                                 msg_set_seqno(m, msg_seqno(msg));
2229                                 tipc_link_tunnel(l_ptr, &tunnel_hdr, m,
2230                                                  msg_link_selector(m));
2231                                 pos += align(msg_size(m));
2232                                 m = (struct tipc_msg *)pos;
2233                         }
2234                 } else {
2235                         tipc_link_tunnel(l_ptr, &tunnel_hdr, msg,
2236                                          msg_link_selector(msg));
2237                 }
2238                 crs = crs->next;
2239         }
2240 }
2241
2242 void tipc_link_send_duplicate(struct tipc_link *l_ptr, struct tipc_link *tunnel)
2243 {
2244         struct sk_buff *iter;
2245         struct tipc_msg tunnel_hdr;
2246
2247         tipc_msg_init(&tunnel_hdr, CHANGEOVER_PROTOCOL,
2248                  DUPLICATE_MSG, INT_H_SIZE, l_ptr->addr);
2249         msg_set_msgcnt(&tunnel_hdr, l_ptr->out_queue_size);
2250         msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
2251         iter = l_ptr->first_out;
2252         while (iter) {
2253                 struct sk_buff *outbuf;
2254                 struct tipc_msg *msg = buf_msg(iter);
2255                 u32 length = msg_size(msg);
2256
2257                 if (msg_user(msg) == MSG_BUNDLER)
2258                         msg_set_type(msg, CLOSED_MSG);
2259                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));   /* Update */
2260                 msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
2261                 msg_set_size(&tunnel_hdr, length + INT_H_SIZE);
2262                 outbuf = tipc_buf_acquire(length + INT_H_SIZE);
2263                 if (outbuf == NULL) {
2264                         pr_warn("%sunable to send duplicate msg\n",
2265                                 link_co_err);
2266                         return;
2267                 }
2268                 skb_copy_to_linear_data(outbuf, &tunnel_hdr, INT_H_SIZE);
2269                 skb_copy_to_linear_data_offset(outbuf, INT_H_SIZE, iter->data,
2270                                                length);
2271                 tipc_link_send_buf(tunnel, outbuf);
2272                 if (!tipc_link_is_up(l_ptr))
2273                         return;
2274                 iter = iter->next;
2275         }
2276 }
2277
2278 /**
2279  * buf_extract - extracts embedded TIPC message from another message
2280  * @skb: encapsulating message buffer
2281  * @from_pos: offset to extract from
2282  *
2283  * Returns a new message buffer containing an embedded message.  The
2284  * encapsulating message itself is left unchanged.
2285  */
2286 static struct sk_buff *buf_extract(struct sk_buff *skb, u32 from_pos)
2287 {
2288         struct tipc_msg *msg = (struct tipc_msg *)(skb->data + from_pos);
2289         u32 size = msg_size(msg);
2290         struct sk_buff *eb;
2291
2292         eb = tipc_buf_acquire(size);
2293         if (eb)
2294                 skb_copy_to_linear_data(eb, msg, size);
2295         return eb;
2296 }
2297
2298 /*
2299  *  link_recv_changeover_msg(): Receive tunneled packet sent
2300  *  via other link. Node is locked. Return extracted buffer.
2301  */
2302 static int link_recv_changeover_msg(struct tipc_link **l_ptr,
2303                                     struct sk_buff **buf)
2304 {
2305         struct sk_buff *tunnel_buf = *buf;
2306         struct tipc_link *dest_link;
2307         struct tipc_msg *msg;
2308         struct tipc_msg *tunnel_msg = buf_msg(tunnel_buf);
2309         u32 msg_typ = msg_type(tunnel_msg);
2310         u32 msg_count = msg_msgcnt(tunnel_msg);
2311
2312         dest_link = (*l_ptr)->owner->links[msg_bearer_id(tunnel_msg)];
2313         if (!dest_link)
2314                 goto exit;
2315         if (dest_link == *l_ptr) {
2316                 pr_err("Unexpected changeover message on link <%s>\n",
2317                        (*l_ptr)->name);
2318                 goto exit;
2319         }
2320         *l_ptr = dest_link;
2321         msg = msg_get_wrapped(tunnel_msg);
2322
2323         if (msg_typ == DUPLICATE_MSG) {
2324                 if (less(msg_seqno(msg), mod(dest_link->next_in_no)))
2325                         goto exit;
2326                 *buf = buf_extract(tunnel_buf, INT_H_SIZE);
2327                 if (*buf == NULL) {
2328                         pr_warn("%sduplicate msg dropped\n", link_co_err);
2329                         goto exit;
2330                 }
2331                 kfree_skb(tunnel_buf);
2332                 return 1;
2333         }
2334
2335         /* First original message ?: */
2336         if (tipc_link_is_up(dest_link)) {
2337                 pr_info("%s<%s>, changeover initiated by peer\n", link_rst_msg,
2338                         dest_link->name);
2339                 tipc_link_reset(dest_link);
2340                 dest_link->exp_msg_count = msg_count;
2341                 if (!msg_count)
2342                         goto exit;
2343         } else if (dest_link->exp_msg_count == START_CHANGEOVER) {
2344                 dest_link->exp_msg_count = msg_count;
2345                 if (!msg_count)
2346                         goto exit;
2347         }
2348
2349         /* Receive original message */
2350         if (dest_link->exp_msg_count == 0) {
2351                 pr_warn("%sgot too many tunnelled messages\n", link_co_err);
2352                 goto exit;
2353         }
2354         dest_link->exp_msg_count--;
2355         if (less(msg_seqno(msg), dest_link->reset_checkpoint)) {
2356                 goto exit;
2357         } else {
2358                 *buf = buf_extract(tunnel_buf, INT_H_SIZE);
2359                 if (*buf != NULL) {
2360                         kfree_skb(tunnel_buf);
2361                         return 1;
2362                 } else {
2363                         pr_warn("%soriginal msg dropped\n", link_co_err);
2364                 }
2365         }
2366 exit:
2367         *buf = NULL;
2368         kfree_skb(tunnel_buf);
2369         return 0;
2370 }
2371
2372 /*
2373  *  Bundler functionality:
2374  */
2375 void tipc_link_recv_bundle(struct sk_buff *buf)
2376 {
2377         u32 msgcount = msg_msgcnt(buf_msg(buf));
2378         u32 pos = INT_H_SIZE;
2379         struct sk_buff *obuf;
2380
2381         while (msgcount--) {
2382                 obuf = buf_extract(buf, pos);
2383                 if (obuf == NULL) {
2384                         pr_warn("Link unable to unbundle message(s)\n");
2385                         break;
2386                 }
2387                 pos += align(msg_size(buf_msg(obuf)));
2388                 tipc_net_route_msg(obuf);
2389         }
2390         kfree_skb(buf);
2391 }
2392
2393 /*
2394  *  Fragmentation/defragmentation:
2395  */
2396
2397 /*
2398  * link_send_long_buf: Entry for buffers needing fragmentation.
2399  * The buffer is complete, inclusive total message length.
2400  * Returns user data length.
2401  */
2402 static int link_send_long_buf(struct tipc_link *l_ptr, struct sk_buff *buf)
2403 {
2404         struct sk_buff *buf_chain = NULL;
2405         struct sk_buff *buf_chain_tail = (struct sk_buff *)&buf_chain;
2406         struct tipc_msg *inmsg = buf_msg(buf);
2407         struct tipc_msg fragm_hdr;
2408         u32 insize = msg_size(inmsg);
2409         u32 dsz = msg_data_sz(inmsg);
2410         unchar *crs = buf->data;
2411         u32 rest = insize;
2412         u32 pack_sz = l_ptr->max_pkt;
2413         u32 fragm_sz = pack_sz - INT_H_SIZE;
2414         u32 fragm_no = 0;
2415         u32 destaddr;
2416
2417         if (msg_short(inmsg))
2418                 destaddr = l_ptr->addr;
2419         else
2420                 destaddr = msg_destnode(inmsg);
2421
2422         /* Prepare reusable fragment header: */
2423         tipc_msg_init(&fragm_hdr, MSG_FRAGMENTER, FIRST_FRAGMENT,
2424                  INT_H_SIZE, destaddr);
2425
2426         /* Chop up message: */
2427         while (rest > 0) {
2428                 struct sk_buff *fragm;
2429
2430                 if (rest <= fragm_sz) {
2431                         fragm_sz = rest;
2432                         msg_set_type(&fragm_hdr, LAST_FRAGMENT);
2433                 }
2434                 fragm = tipc_buf_acquire(fragm_sz + INT_H_SIZE);
2435                 if (fragm == NULL) {
2436                         kfree_skb(buf);
2437                         while (buf_chain) {
2438                                 buf = buf_chain;
2439                                 buf_chain = buf_chain->next;
2440                                 kfree_skb(buf);
2441                         }
2442                         return -ENOMEM;
2443                 }
2444                 msg_set_size(&fragm_hdr, fragm_sz + INT_H_SIZE);
2445                 fragm_no++;
2446                 msg_set_fragm_no(&fragm_hdr, fragm_no);
2447                 skb_copy_to_linear_data(fragm, &fragm_hdr, INT_H_SIZE);
2448                 skb_copy_to_linear_data_offset(fragm, INT_H_SIZE, crs,
2449                                                fragm_sz);
2450                 buf_chain_tail->next = fragm;
2451                 buf_chain_tail = fragm;
2452
2453                 rest -= fragm_sz;
2454                 crs += fragm_sz;
2455                 msg_set_type(&fragm_hdr, FRAGMENT);
2456         }
2457         kfree_skb(buf);
2458
2459         /* Append chain of fragments to send queue & send them */
2460         l_ptr->long_msg_seq_no++;
2461         link_add_chain_to_outqueue(l_ptr, buf_chain, l_ptr->long_msg_seq_no);
2462         l_ptr->stats.sent_fragments += fragm_no;
2463         l_ptr->stats.sent_fragmented++;
2464         tipc_link_push_queue(l_ptr);
2465
2466         return dsz;
2467 }
2468
2469 /*
2470  * A pending message being re-assembled must store certain values
2471  * to handle subsequent fragments correctly. The following functions
2472  * help storing these values in unused, available fields in the
2473  * pending message. This makes dynamic memory allocation unnecessary.
2474  */
2475 static void set_long_msg_seqno(struct sk_buff *buf, u32 seqno)
2476 {
2477         msg_set_seqno(buf_msg(buf), seqno);
2478 }
2479
2480 static u32 get_fragm_size(struct sk_buff *buf)
2481 {
2482         return msg_ack(buf_msg(buf));
2483 }
2484
2485 static void set_fragm_size(struct sk_buff *buf, u32 sz)
2486 {
2487         msg_set_ack(buf_msg(buf), sz);
2488 }
2489
2490 static u32 get_expected_frags(struct sk_buff *buf)
2491 {
2492         return msg_bcast_ack(buf_msg(buf));
2493 }
2494
2495 static void set_expected_frags(struct sk_buff *buf, u32 exp)
2496 {
2497         msg_set_bcast_ack(buf_msg(buf), exp);
2498 }
2499
2500 static u32 get_timer_cnt(struct sk_buff *buf)
2501 {
2502         return msg_reroute_cnt(buf_msg(buf));
2503 }
2504
2505 static void incr_timer_cnt(struct sk_buff *buf)
2506 {
2507         msg_incr_reroute_cnt(buf_msg(buf));
2508 }
2509
2510 /*
2511  * tipc_link_recv_fragment(): Called with node lock on. Returns
2512  * the reassembled buffer if message is complete.
2513  */
2514 int tipc_link_recv_fragment(struct sk_buff **pending, struct sk_buff **fb,
2515                             struct tipc_msg **m)
2516 {
2517         struct sk_buff *prev = NULL;
2518         struct sk_buff *fbuf = *fb;
2519         struct tipc_msg *fragm = buf_msg(fbuf);
2520         struct sk_buff *pbuf = *pending;
2521         u32 long_msg_seq_no = msg_long_msgno(fragm);
2522
2523         *fb = NULL;
2524
2525         /* Is there an incomplete message waiting for this fragment? */
2526         while (pbuf && ((buf_seqno(pbuf) != long_msg_seq_no) ||
2527                         (msg_orignode(fragm) != msg_orignode(buf_msg(pbuf))))) {
2528                 prev = pbuf;
2529                 pbuf = pbuf->next;
2530         }
2531
2532         if (!pbuf && (msg_type(fragm) == FIRST_FRAGMENT)) {
2533                 struct tipc_msg *imsg = (struct tipc_msg *)msg_data(fragm);
2534                 u32 msg_sz = msg_size(imsg);
2535                 u32 fragm_sz = msg_data_sz(fragm);
2536                 u32 exp_fragm_cnt = msg_sz/fragm_sz + !!(msg_sz % fragm_sz);
2537                 u32 max =  TIPC_MAX_USER_MSG_SIZE + NAMED_H_SIZE;
2538                 if (msg_type(imsg) == TIPC_MCAST_MSG)
2539                         max = TIPC_MAX_USER_MSG_SIZE + MCAST_H_SIZE;
2540                 if (msg_size(imsg) > max) {
2541                         kfree_skb(fbuf);
2542                         return 0;
2543                 }
2544                 pbuf = tipc_buf_acquire(msg_size(imsg));
2545                 if (pbuf != NULL) {
2546                         pbuf->next = *pending;
2547                         *pending = pbuf;
2548                         skb_copy_to_linear_data(pbuf, imsg,
2549                                                 msg_data_sz(fragm));
2550                         /*  Prepare buffer for subsequent fragments. */
2551                         set_long_msg_seqno(pbuf, long_msg_seq_no);
2552                         set_fragm_size(pbuf, fragm_sz);
2553                         set_expected_frags(pbuf, exp_fragm_cnt - 1);
2554                 } else {
2555                         pr_debug("Link unable to reassemble fragmented message\n");
2556                         kfree_skb(fbuf);
2557                         return -1;
2558                 }
2559                 kfree_skb(fbuf);
2560                 return 0;
2561         } else if (pbuf && (msg_type(fragm) != FIRST_FRAGMENT)) {
2562                 u32 dsz = msg_data_sz(fragm);
2563                 u32 fsz = get_fragm_size(pbuf);
2564                 u32 crs = ((msg_fragm_no(fragm) - 1) * fsz);
2565                 u32 exp_frags = get_expected_frags(pbuf) - 1;
2566                 skb_copy_to_linear_data_offset(pbuf, crs,
2567                                                msg_data(fragm), dsz);
2568                 kfree_skb(fbuf);
2569
2570                 /* Is message complete? */
2571                 if (exp_frags == 0) {
2572                         if (prev)
2573                                 prev->next = pbuf->next;
2574                         else
2575                                 *pending = pbuf->next;
2576                         msg_reset_reroute_cnt(buf_msg(pbuf));
2577                         *fb = pbuf;
2578                         *m = buf_msg(pbuf);
2579                         return 1;
2580                 }
2581                 set_expected_frags(pbuf, exp_frags);
2582                 return 0;
2583         }
2584         kfree_skb(fbuf);
2585         return 0;
2586 }
2587
2588 /**
2589  * link_check_defragm_bufs - flush stale incoming message fragments
2590  * @l_ptr: pointer to link
2591  */
2592 static void link_check_defragm_bufs(struct tipc_link *l_ptr)
2593 {
2594         struct sk_buff *prev = NULL;
2595         struct sk_buff *next = NULL;
2596         struct sk_buff *buf = l_ptr->defragm_buf;
2597
2598         if (!buf)
2599                 return;
2600         if (!link_working_working(l_ptr))
2601                 return;
2602         while (buf) {
2603                 u32 cnt = get_timer_cnt(buf);
2604
2605                 next = buf->next;
2606                 if (cnt < 4) {
2607                         incr_timer_cnt(buf);
2608                         prev = buf;
2609                 } else {
2610                         if (prev)
2611                                 prev->next = buf->next;
2612                         else
2613                                 l_ptr->defragm_buf = buf->next;
2614                         kfree_skb(buf);
2615                 }
2616                 buf = next;
2617         }
2618 }
2619
2620 static void link_set_supervision_props(struct tipc_link *l_ptr, u32 tolerance)
2621 {
2622         if ((tolerance < TIPC_MIN_LINK_TOL) || (tolerance > TIPC_MAX_LINK_TOL))
2623                 return;
2624
2625         l_ptr->tolerance = tolerance;
2626         l_ptr->continuity_interval =
2627                 ((tolerance / 4) > 500) ? 500 : tolerance / 4;
2628         l_ptr->abort_limit = tolerance / (l_ptr->continuity_interval / 4);
2629 }
2630
2631 void tipc_link_set_queue_limits(struct tipc_link *l_ptr, u32 window)
2632 {
2633         /* Data messages from this node, inclusive FIRST_FRAGM */
2634         l_ptr->queue_limit[TIPC_LOW_IMPORTANCE] = window;
2635         l_ptr->queue_limit[TIPC_MEDIUM_IMPORTANCE] = (window / 3) * 4;
2636         l_ptr->queue_limit[TIPC_HIGH_IMPORTANCE] = (window / 3) * 5;
2637         l_ptr->queue_limit[TIPC_CRITICAL_IMPORTANCE] = (window / 3) * 6;
2638         /* Transiting data messages,inclusive FIRST_FRAGM */
2639         l_ptr->queue_limit[TIPC_LOW_IMPORTANCE + 4] = 300;
2640         l_ptr->queue_limit[TIPC_MEDIUM_IMPORTANCE + 4] = 600;
2641         l_ptr->queue_limit[TIPC_HIGH_IMPORTANCE + 4] = 900;
2642         l_ptr->queue_limit[TIPC_CRITICAL_IMPORTANCE + 4] = 1200;
2643         l_ptr->queue_limit[CONN_MANAGER] = 1200;
2644         l_ptr->queue_limit[CHANGEOVER_PROTOCOL] = 2500;
2645         l_ptr->queue_limit[NAME_DISTRIBUTOR] = 3000;
2646         /* FRAGMENT and LAST_FRAGMENT packets */
2647         l_ptr->queue_limit[MSG_FRAGMENTER] = 4000;
2648 }
2649
2650 /**
2651  * link_find_link - locate link by name
2652  * @name: ptr to link name string
2653  * @node: ptr to area to be filled with ptr to associated node
2654  *
2655  * Caller must hold 'tipc_net_lock' to ensure node and bearer are not deleted;
2656  * this also prevents link deletion.
2657  *
2658  * Returns pointer to link (or 0 if invalid link name).
2659  */
2660 static struct tipc_link *link_find_link(const char *name,
2661                                         struct tipc_node **node)
2662 {
2663         struct tipc_link_name link_name_parts;
2664         struct tipc_bearer *b_ptr;
2665         struct tipc_link *l_ptr;
2666
2667         if (!link_name_validate(name, &link_name_parts))
2668                 return NULL;
2669
2670         b_ptr = tipc_bearer_find_interface(link_name_parts.if_local);
2671         if (!b_ptr)
2672                 return NULL;
2673
2674         *node = tipc_node_find(link_name_parts.addr_peer);
2675         if (!*node)
2676                 return NULL;
2677
2678         l_ptr = (*node)->links[b_ptr->identity];
2679         if (!l_ptr || strcmp(l_ptr->name, name))
2680                 return NULL;
2681
2682         return l_ptr;
2683 }
2684
2685 /**
2686  * link_value_is_valid -- validate proposed link tolerance/priority/window
2687  *
2688  * @cmd: value type (TIPC_CMD_SET_LINK_*)
2689  * @new_value: the new value
2690  *
2691  * Returns 1 if value is within range, 0 if not.
2692  */
2693 static int link_value_is_valid(u16 cmd, u32 new_value)
2694 {
2695         switch (cmd) {
2696         case TIPC_CMD_SET_LINK_TOL:
2697                 return (new_value >= TIPC_MIN_LINK_TOL) &&
2698                         (new_value <= TIPC_MAX_LINK_TOL);
2699         case TIPC_CMD_SET_LINK_PRI:
2700                 return (new_value <= TIPC_MAX_LINK_PRI);
2701         case TIPC_CMD_SET_LINK_WINDOW:
2702                 return (new_value >= TIPC_MIN_LINK_WIN) &&
2703                         (new_value <= TIPC_MAX_LINK_WIN);
2704         }
2705         return 0;
2706 }
2707
2708 /**
2709  * link_cmd_set_value - change priority/tolerance/window for link/bearer/media
2710  * @name: ptr to link, bearer, or media name
2711  * @new_value: new value of link, bearer, or media setting
2712  * @cmd: which link, bearer, or media attribute to set (TIPC_CMD_SET_LINK_*)
2713  *
2714  * Caller must hold 'tipc_net_lock' to ensure link/bearer/media is not deleted.
2715  *
2716  * Returns 0 if value updated and negative value on error.
2717  */
2718 static int link_cmd_set_value(const char *name, u32 new_value, u16 cmd)
2719 {
2720         struct tipc_node *node;
2721         struct tipc_link *l_ptr;
2722         struct tipc_bearer *b_ptr;
2723         struct tipc_media *m_ptr;
2724
2725         l_ptr = link_find_link(name, &node);
2726         if (l_ptr) {
2727                 /*
2728                  * acquire node lock for tipc_link_send_proto_msg().
2729                  * see "TIPC locking policy" in net.c.
2730                  */
2731                 tipc_node_lock(node);
2732                 switch (cmd) {
2733                 case TIPC_CMD_SET_LINK_TOL:
2734                         link_set_supervision_props(l_ptr, new_value);
2735                         tipc_link_send_proto_msg(l_ptr,
2736                                 STATE_MSG, 0, 0, new_value, 0, 0);
2737                         break;
2738                 case TIPC_CMD_SET_LINK_PRI:
2739                         l_ptr->priority = new_value;
2740                         tipc_link_send_proto_msg(l_ptr,
2741                                 STATE_MSG, 0, 0, 0, new_value, 0);
2742                         break;
2743                 case TIPC_CMD_SET_LINK_WINDOW:
2744                         tipc_link_set_queue_limits(l_ptr, new_value);
2745                         break;
2746                 }
2747                 tipc_node_unlock(node);
2748                 return 0;
2749         }
2750
2751         b_ptr = tipc_bearer_find(name);
2752         if (b_ptr) {
2753                 switch (cmd) {
2754                 case TIPC_CMD_SET_LINK_TOL:
2755                         b_ptr->tolerance = new_value;
2756                         return 0;
2757                 case TIPC_CMD_SET_LINK_PRI:
2758                         b_ptr->priority = new_value;
2759                         return 0;
2760                 case TIPC_CMD_SET_LINK_WINDOW:
2761                         b_ptr->window = new_value;
2762                         return 0;
2763                 }
2764                 return -EINVAL;
2765         }
2766
2767         m_ptr = tipc_media_find(name);
2768         if (!m_ptr)
2769                 return -ENODEV;
2770         switch (cmd) {
2771         case TIPC_CMD_SET_LINK_TOL:
2772                 m_ptr->tolerance = new_value;
2773                 return 0;
2774         case TIPC_CMD_SET_LINK_PRI:
2775                 m_ptr->priority = new_value;
2776                 return 0;
2777         case TIPC_CMD_SET_LINK_WINDOW:
2778                 m_ptr->window = new_value;
2779                 return 0;
2780         }
2781         return -EINVAL;
2782 }
2783
2784 struct sk_buff *tipc_link_cmd_config(const void *req_tlv_area, int req_tlv_space,
2785                                      u16 cmd)
2786 {
2787         struct tipc_link_config *args;
2788         u32 new_value;
2789         int res;
2790
2791         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_CONFIG))
2792                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2793
2794         args = (struct tipc_link_config *)TLV_DATA(req_tlv_area);
2795         new_value = ntohl(args->value);
2796
2797         if (!link_value_is_valid(cmd, new_value))
2798                 return tipc_cfg_reply_error_string(
2799                         "cannot change, value invalid");
2800
2801         if (!strcmp(args->name, tipc_bclink_name)) {
2802                 if ((cmd == TIPC_CMD_SET_LINK_WINDOW) &&
2803                     (tipc_bclink_set_queue_limits(new_value) == 0))
2804                         return tipc_cfg_reply_none();
2805                 return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
2806                                                    " (cannot change setting on broadcast link)");
2807         }
2808
2809         read_lock_bh(&tipc_net_lock);
2810         res = link_cmd_set_value(args->name, new_value, cmd);
2811         read_unlock_bh(&tipc_net_lock);
2812         if (res)
2813                 return tipc_cfg_reply_error_string("cannot change link setting");
2814
2815         return tipc_cfg_reply_none();
2816 }
2817
2818 /**
2819  * link_reset_statistics - reset link statistics
2820  * @l_ptr: pointer to link
2821  */
2822 static void link_reset_statistics(struct tipc_link *l_ptr)
2823 {
2824         memset(&l_ptr->stats, 0, sizeof(l_ptr->stats));
2825         l_ptr->stats.sent_info = l_ptr->next_out_no;
2826         l_ptr->stats.recv_info = l_ptr->next_in_no;
2827 }
2828
2829 struct sk_buff *tipc_link_cmd_reset_stats(const void *req_tlv_area, int req_tlv_space)
2830 {
2831         char *link_name;
2832         struct tipc_link *l_ptr;
2833         struct tipc_node *node;
2834
2835         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_NAME))
2836                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2837
2838         link_name = (char *)TLV_DATA(req_tlv_area);
2839         if (!strcmp(link_name, tipc_bclink_name)) {
2840                 if (tipc_bclink_reset_stats())
2841                         return tipc_cfg_reply_error_string("link not found");
2842                 return tipc_cfg_reply_none();
2843         }
2844
2845         read_lock_bh(&tipc_net_lock);
2846         l_ptr = link_find_link(link_name, &node);
2847         if (!l_ptr) {
2848                 read_unlock_bh(&tipc_net_lock);
2849                 return tipc_cfg_reply_error_string("link not found");
2850         }
2851
2852         tipc_node_lock(node);
2853         link_reset_statistics(l_ptr);
2854         tipc_node_unlock(node);
2855         read_unlock_bh(&tipc_net_lock);
2856         return tipc_cfg_reply_none();
2857 }
2858
2859 /**
2860  * percent - convert count to a percentage of total (rounding up or down)
2861  */
2862 static u32 percent(u32 count, u32 total)
2863 {
2864         return (count * 100 + (total / 2)) / total;
2865 }
2866
2867 /**
2868  * tipc_link_stats - print link statistics
2869  * @name: link name
2870  * @buf: print buffer area
2871  * @buf_size: size of print buffer area
2872  *
2873  * Returns length of print buffer data string (or 0 if error)
2874  */
2875 static int tipc_link_stats(const char *name, char *buf, const u32 buf_size)
2876 {
2877         struct tipc_link *l;
2878         struct tipc_stats *s;
2879         struct tipc_node *node;
2880         char *status;
2881         u32 profile_total = 0;
2882         int ret;
2883
2884         if (!strcmp(name, tipc_bclink_name))
2885                 return tipc_bclink_stats(buf, buf_size);
2886
2887         read_lock_bh(&tipc_net_lock);
2888         l = link_find_link(name, &node);
2889         if (!l) {
2890                 read_unlock_bh(&tipc_net_lock);
2891                 return 0;
2892         }
2893         tipc_node_lock(node);
2894         s = &l->stats;
2895
2896         if (tipc_link_is_active(l))
2897                 status = "ACTIVE";
2898         else if (tipc_link_is_up(l))
2899                 status = "STANDBY";
2900         else
2901                 status = "DEFUNCT";
2902
2903         ret = tipc_snprintf(buf, buf_size, "Link <%s>\n"
2904                             "  %s  MTU:%u  Priority:%u  Tolerance:%u ms"
2905                             "  Window:%u packets\n",
2906                             l->name, status, l->max_pkt, l->priority,
2907                             l->tolerance, l->queue_limit[0]);
2908
2909         ret += tipc_snprintf(buf + ret, buf_size - ret,
2910                              "  RX packets:%u fragments:%u/%u bundles:%u/%u\n",
2911                              l->next_in_no - s->recv_info, s->recv_fragments,
2912                              s->recv_fragmented, s->recv_bundles,
2913                              s->recv_bundled);
2914
2915         ret += tipc_snprintf(buf + ret, buf_size - ret,
2916                              "  TX packets:%u fragments:%u/%u bundles:%u/%u\n",
2917                              l->next_out_no - s->sent_info, s->sent_fragments,
2918                              s->sent_fragmented, s->sent_bundles,
2919                              s->sent_bundled);
2920
2921         profile_total = s->msg_length_counts;
2922         if (!profile_total)
2923                 profile_total = 1;
2924
2925         ret += tipc_snprintf(buf + ret, buf_size - ret,
2926                              "  TX profile sample:%u packets  average:%u octets\n"
2927                              "  0-64:%u%% -256:%u%% -1024:%u%% -4096:%u%% "
2928                              "-16384:%u%% -32768:%u%% -66000:%u%%\n",
2929                              s->msg_length_counts,
2930                              s->msg_lengths_total / profile_total,
2931                              percent(s->msg_length_profile[0], profile_total),
2932                              percent(s->msg_length_profile[1], profile_total),
2933                              percent(s->msg_length_profile[2], profile_total),
2934                              percent(s->msg_length_profile[3], profile_total),
2935                              percent(s->msg_length_profile[4], profile_total),
2936                              percent(s->msg_length_profile[5], profile_total),
2937                              percent(s->msg_length_profile[6], profile_total));
2938
2939         ret += tipc_snprintf(buf + ret, buf_size - ret,
2940                              "  RX states:%u probes:%u naks:%u defs:%u"
2941                              " dups:%u\n", s->recv_states, s->recv_probes,
2942                              s->recv_nacks, s->deferred_recv, s->duplicates);
2943
2944         ret += tipc_snprintf(buf + ret, buf_size - ret,
2945                              "  TX states:%u probes:%u naks:%u acks:%u"
2946                              " dups:%u\n", s->sent_states, s->sent_probes,
2947                              s->sent_nacks, s->sent_acks, s->retransmitted);
2948
2949         ret += tipc_snprintf(buf + ret, buf_size - ret,
2950                              "  Congestion link:%u  Send queue"
2951                              " max:%u avg:%u\n", s->link_congs,
2952                              s->max_queue_sz, s->queue_sz_counts ?
2953                              (s->accu_queue_sz / s->queue_sz_counts) : 0);
2954
2955         tipc_node_unlock(node);
2956         read_unlock_bh(&tipc_net_lock);
2957         return ret;
2958 }
2959
2960 struct sk_buff *tipc_link_cmd_show_stats(const void *req_tlv_area, int req_tlv_space)
2961 {
2962         struct sk_buff *buf;
2963         struct tlv_desc *rep_tlv;
2964         int str_len;
2965         int pb_len;
2966         char *pb;
2967
2968         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_NAME))
2969                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2970
2971         buf = tipc_cfg_reply_alloc(TLV_SPACE(ULTRA_STRING_MAX_LEN));
2972         if (!buf)
2973                 return NULL;
2974
2975         rep_tlv = (struct tlv_desc *)buf->data;
2976         pb = TLV_DATA(rep_tlv);
2977         pb_len = ULTRA_STRING_MAX_LEN;
2978         str_len = tipc_link_stats((char *)TLV_DATA(req_tlv_area),
2979                                   pb, pb_len);
2980         if (!str_len) {
2981                 kfree_skb(buf);
2982                 return tipc_cfg_reply_error_string("link not found");
2983         }
2984         str_len += 1;   /* for "\0" */
2985         skb_put(buf, TLV_SPACE(str_len));
2986         TLV_SET(rep_tlv, TIPC_TLV_ULTRA_STRING, NULL, str_len);
2987
2988         return buf;
2989 }
2990
2991 /**
2992  * tipc_link_get_max_pkt - get maximum packet size to use when sending to destination
2993  * @dest: network address of destination node
2994  * @selector: used to select from set of active links
2995  *
2996  * If no active link can be found, uses default maximum packet size.
2997  */
2998 u32 tipc_link_get_max_pkt(u32 dest, u32 selector)
2999 {
3000         struct tipc_node *n_ptr;
3001         struct tipc_link *l_ptr;
3002         u32 res = MAX_PKT_DEFAULT;
3003
3004         if (dest == tipc_own_addr)
3005                 return MAX_MSG_SIZE;
3006
3007         read_lock_bh(&tipc_net_lock);
3008         n_ptr = tipc_node_find(dest);
3009         if (n_ptr) {
3010                 tipc_node_lock(n_ptr);
3011                 l_ptr = n_ptr->active_links[selector & 1];
3012                 if (l_ptr)
3013                         res = l_ptr->max_pkt;
3014                 tipc_node_unlock(n_ptr);
3015         }
3016         read_unlock_bh(&tipc_net_lock);
3017         return res;
3018 }
3019
3020 static void link_print(struct tipc_link *l_ptr, const char *str)
3021 {
3022         pr_info("%s Link %x<%s>:", str, l_ptr->addr, l_ptr->b_ptr->name);
3023
3024         if (link_working_unknown(l_ptr))
3025                 pr_cont(":WU\n");
3026         else if (link_reset_reset(l_ptr))
3027                 pr_cont(":RR\n");
3028         else if (link_reset_unknown(l_ptr))
3029                 pr_cont(":RU\n");
3030         else if (link_working_working(l_ptr))
3031                 pr_cont(":WW\n");
3032         else
3033                 pr_cont("\n");
3034 }