net/tipc/link.c

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