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 /*
  46  * Out-of-range value for link session numbers
  47  */
  48
  49 #define INVALID_SESSION 0x10000
  50
  51 /*
  52  * Link state events:
  53  */
  54
  55 #define  STARTING_EVT    856384768      /* link processing trigger */
  56 #define  TRAFFIC_MSG_EVT 560815u        /* rx'd ??? */
  57 #define  TIMEOUT_EVT     560817u        /* link timer expired */
  58
  59 /*
  60  * The following two 'message types' is really just implementation
  61  * data conveniently stored in the message header.
  62  * They must not be considered part of the protocol
  63  */
  64 #define OPEN_MSG   0
  65 #define CLOSED_MSG 1
  66
  67 /*
  68  * State value stored in 'exp_msg_count'
  69  */
  70
  71 #define START_CHANGEOVER 100000u
  72
  73 /**
  74  * struct tipc_link_name - deconstructed link name
  75  * @addr_local: network address of node at this end
  76  * @if_local: name of interface at this end
  77  * @addr_peer: network address of node at far end
  78  * @if_peer: name of interface at far end
  79  */
  80
  81 struct tipc_link_name {
  82         u32 addr_local;
  83         char if_local[TIPC_MAX_IF_NAME];
  84         u32 addr_peer;
  85         char if_peer[TIPC_MAX_IF_NAME];
  86 };
  87
  88 static void link_handle_out_of_seq_msg(struct tipc_link *l_ptr,
  89                                        struct sk_buff *buf);
  90 static void link_recv_proto_msg(struct tipc_link *l_ptr, struct sk_buff *buf);
  91 static int  link_recv_changeover_msg(struct tipc_link **l_ptr,
  92                                      struct sk_buff **buf);
  93 static void link_set_supervision_props(struct tipc_link *l_ptr, u32 tolerance);
  94 static int  link_send_sections_long(struct tipc_port *sender,
  95                                     struct iovec const *msg_sect,
  96                                     u32 num_sect, unsigned int total_len,
  97                                     u32 destnode);
  98 static void link_check_defragm_bufs(struct tipc_link *l_ptr);
  99 static void link_state_event(struct tipc_link *l_ptr, u32 event);
 100 static void link_reset_statistics(struct tipc_link *l_ptr);
 101 static void link_print(struct tipc_link *l_ptr, const char *str);
 102 static void link_start(struct tipc_link *l_ptr);
 103 static int link_send_long_buf(struct tipc_link *l_ptr, struct sk_buff *buf);
 104
 105 /*
 106  *  Simple link routines
 107  */
 108
 109 static unsigned int align(unsigned int i)
 110 {
 111         return (i + 3) & ~3u;
 112 }
 113
 114 static void link_init_max_pkt(struct tipc_link *l_ptr)
 115 {
 116         u32 max_pkt;
 117
 118         max_pkt = (l_ptr->b_ptr->mtu & ~3);
 119         if (max_pkt > MAX_MSG_SIZE)
 120                 max_pkt = MAX_MSG_SIZE;
 121
 122         l_ptr->max_pkt_target = max_pkt;
 123         if (l_ptr->max_pkt_target < MAX_PKT_DEFAULT)
 124                 l_ptr->max_pkt = l_ptr->max_pkt_target;
 125         else
 126                 l_ptr->max_pkt = MAX_PKT_DEFAULT;
 127
 128         l_ptr->max_pkt_probes = 0;
 129 }
 130
 131 static u32 link_next_sent(struct tipc_link *l_ptr)
 132 {
 133         if (l_ptr->next_out)
 134                 return buf_seqno(l_ptr->next_out);
 135         return mod(l_ptr->next_out_no);
 136 }
 137
 138 static u32 link_last_sent(struct tipc_link *l_ptr)
 139 {
 140         return mod(link_next_sent(l_ptr) - 1);
 141 }
 142
 143 /*
 144  *  Simple non-static link routines (i.e. referenced outside this file)
 145  */
 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
 168 static int link_name_validate(const char *name,
 169                                 struct tipc_link_name *name_parts)
 170 {
 171         char name_copy[TIPC_MAX_LINK_NAME];
 172         char *addr_local;
 173         char *if_local;
 174         char *addr_peer;
 175         char *if_peer;
 176         char dummy;
 177         u32 z_local, c_local, n_local;
 178         u32 z_peer, c_peer, n_peer;
 179         u32 if_local_len;
 180         u32 if_peer_len;
 181
 182         /* copy link name & ensure length is OK */
 183
 184         name_copy[TIPC_MAX_LINK_NAME - 1] = 0;
 185         /* need above in case non-Posix strncpy() doesn't pad with nulls */
 186         strncpy(name_copy, name, TIPC_MAX_LINK_NAME);
 187         if (name_copy[TIPC_MAX_LINK_NAME - 1] != 0)
 188                 return 0;
 189
 190         /* ensure all component parts of link name are present */
 191
 192         addr_local = name_copy;
 193         if_local = strchr(addr_local, ':');
 194         if (if_local == NULL)
 195                 return 0;
 196         *(if_local++) = 0;
 197         addr_peer = strchr(if_local, '-');
 198         if (addr_peer == NULL)
 199                 return 0;
 200         *(addr_peer++) = 0;
 201         if_local_len = addr_peer - if_local;
 202         if_peer = strchr(addr_peer, ':');
 203         if (if_peer == NULL)
 204                 return 0;
 205         *(if_peer++) = 0;
 206         if_peer_len = strlen(if_peer) + 1;
 207
 208         /* validate component parts of link name */
 209
 210         if ((sscanf(addr_local, "%u.%u.%u%c",
 211                     &z_local, &c_local, &n_local, &dummy) != 3) ||
 212             (sscanf(addr_peer, "%u.%u.%u%c",
 213                     &z_peer, &c_peer, &n_peer, &dummy) != 3) ||
 214             (z_local > 255) || (c_local > 4095) || (n_local > 4095) ||
 215             (z_peer  > 255) || (c_peer  > 4095) || (n_peer  > 4095) ||
 216             (if_local_len <= 1) || (if_local_len > TIPC_MAX_IF_NAME) ||
 217             (if_peer_len  <= 1) || (if_peer_len  > TIPC_MAX_IF_NAME) ||
 218             (strspn(if_local, tipc_alphabet) != (if_local_len - 1)) ||
 219             (strspn(if_peer, tipc_alphabet) != (if_peer_len - 1)))
 220                 return 0;
 221
 222         /* return link name components, if necessary */
 223
 224         if (name_parts) {
 225                 name_parts->addr_local = tipc_addr(z_local, c_local, n_local);
 226                 strcpy(name_parts->if_local, if_local);
 227                 name_parts->addr_peer = tipc_addr(z_peer, c_peer, n_peer);
 228                 strcpy(name_parts->if_peer, if_peer);
 229         }
 230         return 1;
 231 }
 232
 233 /**
 234  * link_timeout - handle expiration of link timer
 235  * @l_ptr: pointer to link
 236  *
 237  * This routine must not grab "tipc_net_lock" to avoid a potential deadlock conflict
 238  * with tipc_link_delete().  (There is no risk that the node will be deleted by
 239  * another thread because tipc_link_delete() always cancels the link timer before
 240  * tipc_node_delete() is called.)
 241  */
 242
 243 static void link_timeout(struct tipc_link *l_ptr)
 244 {
 245         tipc_node_lock(l_ptr->owner);
 246
 247         /* update counters used in statistical profiling of send traffic */
 248
 249         l_ptr->stats.accu_queue_sz += l_ptr->out_queue_size;
 250         l_ptr->stats.queue_sz_counts++;
 251
 252         if (l_ptr->first_out) {
 253                 struct tipc_msg *msg = buf_msg(l_ptr->first_out);
 254                 u32 length = msg_size(msg);
 255
 256                 if ((msg_user(msg) == MSG_FRAGMENTER) &&
 257                     (msg_type(msg) == FIRST_FRAGMENT)) {
 258                         length = msg_size(msg_get_wrapped(msg));
 259                 }
 260                 if (length) {
 261                         l_ptr->stats.msg_lengths_total += length;
 262                         l_ptr->stats.msg_length_counts++;
 263                         if (length <= 64)
 264                                 l_ptr->stats.msg_length_profile[0]++;
 265                         else if (length <= 256)
 266                                 l_ptr->stats.msg_length_profile[1]++;
 267                         else if (length <= 1024)
 268                                 l_ptr->stats.msg_length_profile[2]++;
 269                         else if (length <= 4096)
 270                                 l_ptr->stats.msg_length_profile[3]++;
 271                         else if (length <= 16384)
 272                                 l_ptr->stats.msg_length_profile[4]++;
 273                         else if (length <= 32768)
 274                                 l_ptr->stats.msg_length_profile[5]++;
 275                         else
 276                                 l_ptr->stats.msg_length_profile[6]++;
 277                 }
 278         }
 279
 280         /* do all other link processing performed on a periodic basis */
 281
 282         link_check_defragm_bufs(l_ptr);
 283
 284         link_state_event(l_ptr, TIMEOUT_EVT);
 285
 286         if (l_ptr->next_out)
 287                 tipc_link_push_queue(l_ptr);
 288
 289         tipc_node_unlock(l_ptr->owner);
 290 }
 291
 292 static void link_set_timer(struct tipc_link *l_ptr, u32 time)
 293 {
 294         k_start_timer(&l_ptr->timer, time);
 295 }
 296
 297 /**
 298  * tipc_link_create - create a new link
 299  * @n_ptr: pointer to associated node
 300  * @b_ptr: pointer to associated bearer
 301  * @media_addr: media address to use when sending messages over link
 302  *
 303  * Returns pointer to link.
 304  */
 305
 306 struct tipc_link *tipc_link_create(struct tipc_node *n_ptr,
 307                               struct tipc_bearer *b_ptr,
 308                               const struct tipc_media_addr *media_addr)
 309 {
 310         struct tipc_link *l_ptr;
 311         struct tipc_msg *msg;
 312         char *if_name;
 313         char addr_string[16];
 314         u32 peer = n_ptr->addr;
 315
 316         if (n_ptr->link_cnt >= 2) {
 317                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 318                 err("Attempt to establish third link to %s\n", addr_string);
 319                 return NULL;
 320         }
 321
 322         if (n_ptr->links[b_ptr->identity]) {
 323                 tipc_addr_string_fill(addr_string, n_ptr->addr);
 324                 err("Attempt to establish second link on <%s> to %s\n",
 325                     b_ptr->name, addr_string);
 326                 return NULL;
 327         }
 328
 329         l_ptr = kzalloc(sizeof(*l_ptr), GFP_ATOMIC);
 330         if (!l_ptr) {
 331                 warn("Link creation failed, no memory\n");
 332                 return NULL;
 333         }
 334
 335         l_ptr->addr = peer;
 336         if_name = strchr(b_ptr->name, ':') + 1;
 337         sprintf(l_ptr->name, "%u.%u.%u:%s-%u.%u.%u:unknown",
 338                 tipc_zone(tipc_own_addr), tipc_cluster(tipc_own_addr),
 339                 tipc_node(tipc_own_addr),
 340                 if_name,
 341                 tipc_zone(peer), tipc_cluster(peer), tipc_node(peer));
 342                 /* note: peer i/f name is updated by reset/activate message */
 343         memcpy(&l_ptr->media_addr, media_addr, sizeof(*media_addr));
 344         l_ptr->owner = n_ptr;
 345         l_ptr->checkpoint = 1;
 346         l_ptr->peer_session = INVALID_SESSION;
 347         l_ptr->b_ptr = b_ptr;
 348         link_set_supervision_props(l_ptr, b_ptr->tolerance);
 349         l_ptr->state = RESET_UNKNOWN;
 350
 351         l_ptr->pmsg = (struct tipc_msg *)&l_ptr->proto_msg;
 352         msg = l_ptr->pmsg;
 353         tipc_msg_init(msg, LINK_PROTOCOL, RESET_MSG, INT_H_SIZE, l_ptr->addr);
 354         msg_set_size(msg, sizeof(l_ptr->proto_msg));
 355         msg_set_session(msg, (tipc_random & 0xffff));
 356         msg_set_bearer_id(msg, b_ptr->identity);
 357         strcpy((char *)msg_data(msg), if_name);
 358
 359         l_ptr->priority = b_ptr->priority;
 360         tipc_link_set_queue_limits(l_ptr, b_ptr->window);
 361
 362         link_init_max_pkt(l_ptr);
 363
 364         l_ptr->next_out_no = 1;
 365         INIT_LIST_HEAD(&l_ptr->waiting_ports);
 366
 367         link_reset_statistics(l_ptr);
 368
 369         tipc_node_attach_link(n_ptr, l_ptr);
 370
 371         k_init_timer(&l_ptr->timer, (Handler)link_timeout, (unsigned long)l_ptr);
 372         list_add_tail(&l_ptr->link_list, &b_ptr->links);
 373         tipc_k_signal((Handler)link_start, (unsigned long)l_ptr);
 374
 375         return l_ptr;
 376 }
 377
 378 /**
 379  * tipc_link_delete - delete a link
 380  * @l_ptr: pointer to link
 381  *
 382  * Note: 'tipc_net_lock' is write_locked, bearer is locked.
 383  * This routine must not grab the node lock until after link timer cancellation
 384  * to avoid a potential deadlock situation.
 385  */
 386
 387 void tipc_link_delete(struct tipc_link *l_ptr)
 388 {
 389         if (!l_ptr) {
 390                 err("Attempt to delete non-existent link\n");
 391                 return;
 392         }
 393
 394         k_cancel_timer(&l_ptr->timer);
 395
 396         tipc_node_lock(l_ptr->owner);
 397         tipc_link_reset(l_ptr);
 398         tipc_node_detach_link(l_ptr->owner, l_ptr);
 399         tipc_link_stop(l_ptr);
 400         list_del_init(&l_ptr->link_list);
 401         tipc_node_unlock(l_ptr->owner);
 402         k_term_timer(&l_ptr->timer);
 403         kfree(l_ptr);
 404 }
 405
 406 static void link_start(struct tipc_link *l_ptr)
 407 {
 408         tipc_node_lock(l_ptr->owner);
 409         link_state_event(l_ptr, STARTING_EVT);
 410         tipc_node_unlock(l_ptr->owner);
 411 }
 412
 413 /**
 414  * link_schedule_port - schedule port for deferred sending
 415  * @l_ptr: pointer to link
 416  * @origport: reference to sending port
 417  * @sz: amount of data to be sent
 418  *
 419  * Schedules port for renewed sending of messages after link congestion
 420  * has abated.
 421  */
 422
 423 static int link_schedule_port(struct tipc_link *l_ptr, u32 origport, u32 sz)
 424 {
 425         struct tipc_port *p_ptr;
 426
 427         spin_lock_bh(&tipc_port_list_lock);
 428         p_ptr = tipc_port_lock(origport);
 429         if (p_ptr) {
 430                 if (!p_ptr->wakeup)
 431                         goto exit;
 432                 if (!list_empty(&p_ptr->wait_list))
 433                         goto exit;
 434                 p_ptr->congested = 1;
 435                 p_ptr->waiting_pkts = 1 + ((sz - 1) / l_ptr->max_pkt);
 436                 list_add_tail(&p_ptr->wait_list, &l_ptr->waiting_ports);
 437                 l_ptr->stats.link_congs++;
 438 exit:
 439                 tipc_port_unlock(p_ptr);
 440         }
 441         spin_unlock_bh(&tipc_port_list_lock);
 442         return -ELINKCONG;
 443 }
 444
 445 void tipc_link_wakeup_ports(struct tipc_link *l_ptr, int all)
 446 {
 447         struct tipc_port *p_ptr;
 448         struct tipc_port *temp_p_ptr;
 449         int win = l_ptr->queue_limit[0] - l_ptr->out_queue_size;
 450
 451         if (all)
 452                 win = 100000;
 453         if (win <= 0)
 454                 return;
 455         if (!spin_trylock_bh(&tipc_port_list_lock))
 456                 return;
 457         if (link_congested(l_ptr))
 458                 goto exit;
 459         list_for_each_entry_safe(p_ptr, temp_p_ptr, &l_ptr->waiting_ports,
 460                                  wait_list) {
 461                 if (win <= 0)
 462                         break;
 463                 list_del_init(&p_ptr->wait_list);
 464                 spin_lock_bh(p_ptr->lock);
 465                 p_ptr->congested = 0;
 466                 p_ptr->wakeup(p_ptr);
 467                 win -= p_ptr->waiting_pkts;
 468                 spin_unlock_bh(p_ptr->lock);
 469         }
 470
 471 exit:
 472         spin_unlock_bh(&tipc_port_list_lock);
 473 }
 474
 475 /**
 476  * link_release_outqueue - purge link's outbound message queue
 477  * @l_ptr: pointer to link
 478  */
 479
 480 static void link_release_outqueue(struct tipc_link *l_ptr)
 481 {
 482         struct sk_buff *buf = l_ptr->first_out;
 483         struct sk_buff *next;
 484
 485         while (buf) {
 486                 next = buf->next;
 487                 buf_discard(buf);
 488                 buf = next;
 489         }
 490         l_ptr->first_out = NULL;
 491         l_ptr->out_queue_size = 0;
 492 }
 493
 494 /**
 495  * tipc_link_reset_fragments - purge link's inbound message fragments queue
 496  * @l_ptr: pointer to link
 497  */
 498
 499 void tipc_link_reset_fragments(struct tipc_link *l_ptr)
 500 {
 501         struct sk_buff *buf = l_ptr->defragm_buf;
 502         struct sk_buff *next;
 503
 504         while (buf) {
 505                 next = buf->next;
 506                 buf_discard(buf);
 507                 buf = next;
 508         }
 509         l_ptr->defragm_buf = NULL;
 510 }
 511
 512 /**
 513  * tipc_link_stop - purge all inbound and outbound messages associated with link
 514  * @l_ptr: pointer to link
 515  */
 516
 517 void tipc_link_stop(struct tipc_link *l_ptr)
 518 {
 519         struct sk_buff *buf;
 520         struct sk_buff *next;
 521
 522         buf = l_ptr->oldest_deferred_in;
 523         while (buf) {
 524                 next = buf->next;
 525                 buf_discard(buf);
 526                 buf = next;
 527         }
 528
 529         buf = l_ptr->first_out;
 530         while (buf) {
 531                 next = buf->next;
 532                 buf_discard(buf);
 533                 buf = next;
 534         }
 535
 536         tipc_link_reset_fragments(l_ptr);
 537
 538         buf_discard(l_ptr->proto_msg_queue);
 539         l_ptr->proto_msg_queue = NULL;
 540 }
 541
 542 void tipc_link_reset(struct tipc_link *l_ptr)
 543 {
 544         struct sk_buff *buf;
 545         u32 prev_state = l_ptr->state;
 546         u32 checkpoint = l_ptr->next_in_no;
 547         int was_active_link = tipc_link_is_active(l_ptr);
 548
 549         msg_set_session(l_ptr->pmsg, ((msg_session(l_ptr->pmsg) + 1) & 0xffff));
 550
 551         /* Link is down, accept any session */
 552         l_ptr->peer_session = INVALID_SESSION;
 553
 554         /* Prepare for max packet size negotiation */
 555         link_init_max_pkt(l_ptr);
 556
 557         l_ptr->state = RESET_UNKNOWN;
 558
 559         if ((prev_state == RESET_UNKNOWN) || (prev_state == RESET_RESET))
 560                 return;
 561
 562         tipc_node_link_down(l_ptr->owner, l_ptr);
 563         tipc_bearer_remove_dest(l_ptr->b_ptr, l_ptr->addr);
 564
 565         if (was_active_link && tipc_node_active_links(l_ptr->owner) &&
 566             l_ptr->owner->permit_changeover) {
 567                 l_ptr->reset_checkpoint = checkpoint;
 568                 l_ptr->exp_msg_count = START_CHANGEOVER;
 569         }
 570
 571         /* Clean up all queues: */
 572
 573         link_release_outqueue(l_ptr);
 574         buf_discard(l_ptr->proto_msg_queue);
 575         l_ptr->proto_msg_queue = NULL;
 576         buf = l_ptr->oldest_deferred_in;
 577         while (buf) {
 578                 struct sk_buff *next = buf->next;
 579                 buf_discard(buf);
 580                 buf = next;
 581         }
 582         if (!list_empty(&l_ptr->waiting_ports))
 583                 tipc_link_wakeup_ports(l_ptr, 1);
 584
 585         l_ptr->retransm_queue_head = 0;
 586         l_ptr->retransm_queue_size = 0;
 587         l_ptr->last_out = NULL;
 588         l_ptr->first_out = NULL;
 589         l_ptr->next_out = NULL;
 590         l_ptr->unacked_window = 0;
 591         l_ptr->checkpoint = 1;
 592         l_ptr->next_out_no = 1;
 593         l_ptr->deferred_inqueue_sz = 0;
 594         l_ptr->oldest_deferred_in = NULL;
 595         l_ptr->newest_deferred_in = NULL;
 596         l_ptr->fsm_msg_cnt = 0;
 597         l_ptr->stale_count = 0;
 598         link_reset_statistics(l_ptr);
 599 }
 600
 601
 602 static void link_activate(struct tipc_link *l_ptr)
 603 {
 604         l_ptr->next_in_no = l_ptr->stats.recv_info = 1;
 605         tipc_node_link_up(l_ptr->owner, l_ptr);
 606         tipc_bearer_add_dest(l_ptr->b_ptr, l_ptr->addr);
 607 }
 608
 609 /**
 610  * link_state_event - link finite state machine
 611  * @l_ptr: pointer to link
 612  * @event: state machine event to process
 613  */
 614
 615 static void link_state_event(struct tipc_link *l_ptr, unsigned event)
 616 {
 617         struct tipc_link *other;
 618         u32 cont_intv = l_ptr->continuity_interval;
 619
 620         if (!l_ptr->started && (event != STARTING_EVT))
 621                 return;         /* Not yet. */
 622
 623         if (link_blocked(l_ptr)) {
 624                 if (event == TIMEOUT_EVT)
 625                         link_set_timer(l_ptr, cont_intv);
 626                 return;   /* Changeover going on */
 627         }
 628
 629         switch (l_ptr->state) {
 630         case WORKING_WORKING:
 631                 switch (event) {
 632                 case TRAFFIC_MSG_EVT:
 633                 case ACTIVATE_MSG:
 634                         break;
 635                 case TIMEOUT_EVT:
 636                         if (l_ptr->next_in_no != l_ptr->checkpoint) {
 637                                 l_ptr->checkpoint = l_ptr->next_in_no;
 638                                 if (tipc_bclink_acks_missing(l_ptr->owner)) {
 639                                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
 640                                                                  0, 0, 0, 0, 0);
 641                                         l_ptr->fsm_msg_cnt++;
 642                                 } else if (l_ptr->max_pkt < l_ptr->max_pkt_target) {
 643                                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
 644                                                                  1, 0, 0, 0, 0);
 645                                         l_ptr->fsm_msg_cnt++;
 646                                 }
 647                                 link_set_timer(l_ptr, cont_intv);
 648                                 break;
 649                         }
 650                         l_ptr->state = WORKING_UNKNOWN;
 651                         l_ptr->fsm_msg_cnt = 0;
 652                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
 653                         l_ptr->fsm_msg_cnt++;
 654                         link_set_timer(l_ptr, cont_intv / 4);
 655                         break;
 656                 case RESET_MSG:
 657                         info("Resetting link <%s>, requested by peer\n",
 658                              l_ptr->name);
 659                         tipc_link_reset(l_ptr);
 660                         l_ptr->state = RESET_RESET;
 661                         l_ptr->fsm_msg_cnt = 0;
 662                         tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
 663                         l_ptr->fsm_msg_cnt++;
 664                         link_set_timer(l_ptr, cont_intv);
 665                         break;
 666                 default:
 667                         err("Unknown link event %u in WW state\n", event);
 668                 }
 669                 break;
 670         case WORKING_UNKNOWN:
 671                 switch (event) {
 672                 case TRAFFIC_MSG_EVT:
 673                 case ACTIVATE_MSG:
 674                         l_ptr->state = WORKING_WORKING;
 675                         l_ptr->fsm_msg_cnt = 0;
 676                         link_set_timer(l_ptr, cont_intv);
 677                         break;
 678                 case RESET_MSG:
 679                         info("Resetting link <%s>, requested by peer "
 680                              "while probing\n", l_ptr->name);
 681                         tipc_link_reset(l_ptr);
 682                         l_ptr->state = RESET_RESET;
 683                         l_ptr->fsm_msg_cnt = 0;
 684                         tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
 685                         l_ptr->fsm_msg_cnt++;
 686                         link_set_timer(l_ptr, cont_intv);
 687                         break;
 688                 case TIMEOUT_EVT:
 689                         if (l_ptr->next_in_no != l_ptr->checkpoint) {
 690                                 l_ptr->state = WORKING_WORKING;
 691                                 l_ptr->fsm_msg_cnt = 0;
 692                                 l_ptr->checkpoint = l_ptr->next_in_no;
 693                                 if (tipc_bclink_acks_missing(l_ptr->owner)) {
 694                                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
 695                                                                  0, 0, 0, 0, 0);
 696                                         l_ptr->fsm_msg_cnt++;
 697                                 }
 698                                 link_set_timer(l_ptr, cont_intv);
 699                         } else if (l_ptr->fsm_msg_cnt < l_ptr->abort_limit) {
 700                                 tipc_link_send_proto_msg(l_ptr, STATE_MSG,
 701                                                          1, 0, 0, 0, 0);
 702                                 l_ptr->fsm_msg_cnt++;
 703                                 link_set_timer(l_ptr, cont_intv / 4);
 704                         } else {        /* Link has failed */
 705                                 warn("Resetting link <%s>, peer not responding\n",
 706                                      l_ptr->name);
 707                                 tipc_link_reset(l_ptr);
 708                                 l_ptr->state = RESET_UNKNOWN;
 709                                 l_ptr->fsm_msg_cnt = 0;
 710                                 tipc_link_send_proto_msg(l_ptr, RESET_MSG,
 711                                                          0, 0, 0, 0, 0);
 712                                 l_ptr->fsm_msg_cnt++;
 713                                 link_set_timer(l_ptr, cont_intv);
 714                         }
 715                         break;
 716                 default:
 717                         err("Unknown link event %u in WU state\n", event);
 718                 }
 719                 break;
 720         case RESET_UNKNOWN:
 721                 switch (event) {
 722                 case TRAFFIC_MSG_EVT:
 723                         break;
 724                 case ACTIVATE_MSG:
 725                         other = l_ptr->owner->active_links[0];
 726                         if (other && link_working_unknown(other))
 727                                 break;
 728                         l_ptr->state = WORKING_WORKING;
 729                         l_ptr->fsm_msg_cnt = 0;
 730                         link_activate(l_ptr);
 731                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
 732                         l_ptr->fsm_msg_cnt++;
 733                         link_set_timer(l_ptr, cont_intv);
 734                         break;
 735                 case RESET_MSG:
 736                         l_ptr->state = RESET_RESET;
 737                         l_ptr->fsm_msg_cnt = 0;
 738                         tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 1, 0, 0, 0, 0);
 739                         l_ptr->fsm_msg_cnt++;
 740                         link_set_timer(l_ptr, cont_intv);
 741                         break;
 742                 case STARTING_EVT:
 743                         l_ptr->started = 1;
 744                         /* fall through */
 745                 case TIMEOUT_EVT:
 746                         tipc_link_send_proto_msg(l_ptr, RESET_MSG, 0, 0, 0, 0, 0);
 747                         l_ptr->fsm_msg_cnt++;
 748                         link_set_timer(l_ptr, cont_intv);
 749                         break;
 750                 default:
 751                         err("Unknown link event %u in RU state\n", event);
 752                 }
 753                 break;
 754         case RESET_RESET:
 755                 switch (event) {
 756                 case TRAFFIC_MSG_EVT:
 757                 case ACTIVATE_MSG:
 758                         other = l_ptr->owner->active_links[0];
 759                         if (other && link_working_unknown(other))
 760                                 break;
 761                         l_ptr->state = WORKING_WORKING;
 762                         l_ptr->fsm_msg_cnt = 0;
 763                         link_activate(l_ptr);
 764                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
 765                         l_ptr->fsm_msg_cnt++;
 766                         link_set_timer(l_ptr, cont_intv);
 767                         break;
 768                 case RESET_MSG:
 769                         break;
 770                 case TIMEOUT_EVT:
 771                         tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
 772                         l_ptr->fsm_msg_cnt++;
 773                         link_set_timer(l_ptr, cont_intv);
 774                         break;
 775                 default:
 776                         err("Unknown link event %u in RR state\n", event);
 777                 }
 778                 break;
 779         default:
 780                 err("Unknown link state %u/%u\n", l_ptr->state, event);
 781         }
 782 }
 783
 784 /*
 785  * link_bundle_buf(): Append contents of a buffer to
 786  * the tail of an existing one.
 787  */
 788
 789 static int link_bundle_buf(struct tipc_link *l_ptr,
 790                            struct sk_buff *bundler,
 791                            struct sk_buff *buf)
 792 {
 793         struct tipc_msg *bundler_msg = buf_msg(bundler);
 794         struct tipc_msg *msg = buf_msg(buf);
 795         u32 size = msg_size(msg);
 796         u32 bundle_size = msg_size(bundler_msg);
 797         u32 to_pos = align(bundle_size);
 798         u32 pad = to_pos - bundle_size;
 799
 800         if (msg_user(bundler_msg) != MSG_BUNDLER)
 801                 return 0;
 802         if (msg_type(bundler_msg) != OPEN_MSG)
 803                 return 0;
 804         if (skb_tailroom(bundler) < (pad + size))
 805                 return 0;
 806         if (l_ptr->max_pkt < (to_pos + size))
 807                 return 0;
 808
 809         skb_put(bundler, pad + size);
 810         skb_copy_to_linear_data_offset(bundler, to_pos, buf->data, size);
 811         msg_set_size(bundler_msg, to_pos + size);
 812         msg_set_msgcnt(bundler_msg, msg_msgcnt(bundler_msg) + 1);
 813         buf_discard(buf);
 814         l_ptr->stats.sent_bundled++;
 815         return 1;
 816 }
 817
 818 static void link_add_to_outqueue(struct tipc_link *l_ptr,
 819                                  struct sk_buff *buf,
 820                                  struct tipc_msg *msg)
 821 {
 822         u32 ack = mod(l_ptr->next_in_no - 1);
 823         u32 seqno = mod(l_ptr->next_out_no++);
 824
 825         msg_set_word(msg, 2, ((ack << 16) | seqno));
 826         msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
 827         buf->next = NULL;
 828         if (l_ptr->first_out) {
 829                 l_ptr->last_out->next = buf;
 830                 l_ptr->last_out = buf;
 831         } else
 832                 l_ptr->first_out = l_ptr->last_out = buf;
 833
 834         l_ptr->out_queue_size++;
 835         if (l_ptr->out_queue_size > l_ptr->stats.max_queue_sz)
 836                 l_ptr->stats.max_queue_sz = l_ptr->out_queue_size;
 837 }
 838
 839 static void link_add_chain_to_outqueue(struct tipc_link *l_ptr,
 840                                        struct sk_buff *buf_chain,
 841                                        u32 long_msgno)
 842 {
 843         struct sk_buff *buf;
 844         struct tipc_msg *msg;
 845
 846         if (!l_ptr->next_out)
 847                 l_ptr->next_out = buf_chain;
 848         while (buf_chain) {
 849                 buf = buf_chain;
 850                 buf_chain = buf_chain->next;
 851
 852                 msg = buf_msg(buf);
 853                 msg_set_long_msgno(msg, long_msgno);
 854                 link_add_to_outqueue(l_ptr, buf, msg);
 855         }
 856 }
 857
 858 /*
 859  * tipc_link_send_buf() is the 'full path' for messages, called from
 860  * inside TIPC when the 'fast path' in tipc_send_buf
 861  * has failed, and from link_send()
 862  */
 863
 864 int tipc_link_send_buf(struct tipc_link *l_ptr, struct sk_buff *buf)
 865 {
 866         struct tipc_msg *msg = buf_msg(buf);
 867         u32 size = msg_size(msg);
 868         u32 dsz = msg_data_sz(msg);
 869         u32 queue_size = l_ptr->out_queue_size;
 870         u32 imp = tipc_msg_tot_importance(msg);
 871         u32 queue_limit = l_ptr->queue_limit[imp];
 872         u32 max_packet = l_ptr->max_pkt;
 873
 874         msg_set_prevnode(msg, tipc_own_addr);   /* If routed message */
 875
 876         /* Match msg importance against queue limits: */
 877
 878         if (unlikely(queue_size >= queue_limit)) {
 879                 if (imp <= TIPC_CRITICAL_IMPORTANCE) {
 880                         link_schedule_port(l_ptr, msg_origport(msg), size);
 881                         buf_discard(buf);
 882                         return -ELINKCONG;
 883                 }
 884                 buf_discard(buf);
 885                 if (imp > CONN_MANAGER) {
 886                         warn("Resetting link <%s>, send queue full", l_ptr->name);
 887                         tipc_link_reset(l_ptr);
 888                 }
 889                 return dsz;
 890         }
 891
 892         /* Fragmentation needed ? */
 893
 894         if (size > max_packet)
 895                 return link_send_long_buf(l_ptr, buf);
 896
 897         /* Packet can be queued or sent: */
 898
 899         if (likely(!tipc_bearer_congested(l_ptr->b_ptr, l_ptr) &&
 900                    !link_congested(l_ptr))) {
 901                 link_add_to_outqueue(l_ptr, buf, msg);
 902
 903                 if (likely(tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr))) {
 904                         l_ptr->unacked_window = 0;
 905                 } else {
 906                         tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
 907                         l_ptr->stats.bearer_congs++;
 908                         l_ptr->next_out = buf;
 909                 }
 910                 return dsz;
 911         }
 912         /* Congestion: can message be bundled ?: */
 913
 914         if ((msg_user(msg) != CHANGEOVER_PROTOCOL) &&
 915             (msg_user(msg) != MSG_FRAGMENTER)) {
 916
 917                 /* Try adding message to an existing bundle */
 918
 919                 if (l_ptr->next_out &&
 920                     link_bundle_buf(l_ptr, l_ptr->last_out, buf)) {
 921                         tipc_bearer_resolve_congestion(l_ptr->b_ptr, l_ptr);
 922                         return dsz;
 923                 }
 924
 925                 /* Try creating a new bundle */
 926
 927                 if (size <= max_packet * 2 / 3) {
 928                         struct sk_buff *bundler = tipc_buf_acquire(max_packet);
 929                         struct tipc_msg bundler_hdr;
 930
 931                         if (bundler) {
 932                                 tipc_msg_init(&bundler_hdr, MSG_BUNDLER, OPEN_MSG,
 933                                          INT_H_SIZE, l_ptr->addr);
 934                                 skb_copy_to_linear_data(bundler, &bundler_hdr,
 935                                                         INT_H_SIZE);
 936                                 skb_trim(bundler, INT_H_SIZE);
 937                                 link_bundle_buf(l_ptr, bundler, buf);
 938                                 buf = bundler;
 939                                 msg = buf_msg(buf);
 940                                 l_ptr->stats.sent_bundles++;
 941                         }
 942                 }
 943         }
 944         if (!l_ptr->next_out)
 945                 l_ptr->next_out = buf;
 946         link_add_to_outqueue(l_ptr, buf, msg);
 947         tipc_bearer_resolve_congestion(l_ptr->b_ptr, l_ptr);
 948         return dsz;
 949 }
 950
 951 /*
 952  * tipc_link_send(): same as tipc_link_send_buf(), but the link to use has
 953  * not been selected yet, and the the owner node is not locked
 954  * Called by TIPC internal users, e.g. the name distributor
 955  */
 956
 957 int tipc_link_send(struct sk_buff *buf, u32 dest, u32 selector)
 958 {
 959         struct tipc_link *l_ptr;
 960         struct tipc_node *n_ptr;
 961         int res = -ELINKCONG;
 962
 963         read_lock_bh(&tipc_net_lock);
 964         n_ptr = tipc_node_find(dest);
 965         if (n_ptr) {
 966                 tipc_node_lock(n_ptr);
 967                 l_ptr = n_ptr->active_links[selector & 1];
 968                 if (l_ptr)
 969                         res = tipc_link_send_buf(l_ptr, buf);
 970                 else
 971                         buf_discard(buf);
 972                 tipc_node_unlock(n_ptr);
 973         } else {
 974                 buf_discard(buf);
 975         }
 976         read_unlock_bh(&tipc_net_lock);
 977         return res;
 978 }
 979
 980 /*
 981  * tipc_link_send_names - send name table entries to new neighbor
 982  *
 983  * Send routine for bulk delivery of name table messages when contact
 984  * with a new neighbor occurs. No link congestion checking is performed
 985  * because name table messages *must* be delivered. The messages must be
 986  * small enough not to require fragmentation.
 987  * Called without any locks held.
 988  */
 989
 990 void tipc_link_send_names(struct list_head *message_list, u32 dest)
 991 {
 992         struct tipc_node *n_ptr;
 993         struct tipc_link *l_ptr;
 994         struct sk_buff *buf;
 995         struct sk_buff *temp_buf;
 996
 997         if (list_empty(message_list))
 998                 return;
 999
1000         read_lock_bh(&tipc_net_lock);
1001         n_ptr = tipc_node_find(dest);
1002         if (n_ptr) {
1003                 tipc_node_lock(n_ptr);
1004                 l_ptr = n_ptr->active_links[0];
1005                 if (l_ptr) {
1006                         /* convert circular list to linear list */
1007                         ((struct sk_buff *)message_list->prev)->next = NULL;
1008                         link_add_chain_to_outqueue(l_ptr,
1009                                 (struct sk_buff *)message_list->next, 0);
1010                         tipc_link_push_queue(l_ptr);
1011                         INIT_LIST_HEAD(message_list);
1012                 }
1013                 tipc_node_unlock(n_ptr);
1014         }
1015         read_unlock_bh(&tipc_net_lock);
1016
1017         /* discard the messages if they couldn't be sent */
1018
1019         list_for_each_safe(buf, temp_buf, ((struct sk_buff *)message_list)) {
1020                 list_del((struct list_head *)buf);
1021                 buf_discard(buf);
1022         }
1023 }
1024
1025 /*
1026  * link_send_buf_fast: Entry for data messages where the
1027  * destination link is known and the header is complete,
1028  * inclusive total message length. Very time critical.
1029  * Link is locked. Returns user data length.
1030  */
1031
1032 static int link_send_buf_fast(struct tipc_link *l_ptr, struct sk_buff *buf,
1033                               u32 *used_max_pkt)
1034 {
1035         struct tipc_msg *msg = buf_msg(buf);
1036         int res = msg_data_sz(msg);
1037
1038         if (likely(!link_congested(l_ptr))) {
1039                 if (likely(msg_size(msg) <= l_ptr->max_pkt)) {
1040                         if (likely(list_empty(&l_ptr->b_ptr->cong_links))) {
1041                                 link_add_to_outqueue(l_ptr, buf, msg);
1042                                 if (likely(tipc_bearer_send(l_ptr->b_ptr, buf,
1043                                                             &l_ptr->media_addr))) {
1044                                         l_ptr->unacked_window = 0;
1045                                         return res;
1046                                 }
1047                                 tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
1048                                 l_ptr->stats.bearer_congs++;
1049                                 l_ptr->next_out = buf;
1050                                 return res;
1051                         }
1052                 } else
1053                         *used_max_pkt = l_ptr->max_pkt;
1054         }
1055         return tipc_link_send_buf(l_ptr, buf);  /* All other cases */
1056 }
1057
1058 /*
1059  * tipc_send_buf_fast: Entry for data messages where the
1060  * destination node is known and the header is complete,
1061  * inclusive total message length.
1062  * Returns user data length.
1063  */
1064 int tipc_send_buf_fast(struct sk_buff *buf, u32 destnode)
1065 {
1066         struct tipc_link *l_ptr;
1067         struct tipc_node *n_ptr;
1068         int res;
1069         u32 selector = msg_origport(buf_msg(buf)) & 1;
1070         u32 dummy;
1071
1072         read_lock_bh(&tipc_net_lock);
1073         n_ptr = tipc_node_find(destnode);
1074         if (likely(n_ptr)) {
1075                 tipc_node_lock(n_ptr);
1076                 l_ptr = n_ptr->active_links[selector];
1077                 if (likely(l_ptr)) {
1078                         res = link_send_buf_fast(l_ptr, buf, &dummy);
1079                         tipc_node_unlock(n_ptr);
1080                         read_unlock_bh(&tipc_net_lock);
1081                         return res;
1082                 }
1083                 tipc_node_unlock(n_ptr);
1084         }
1085         read_unlock_bh(&tipc_net_lock);
1086         res = msg_data_sz(buf_msg(buf));
1087         tipc_reject_msg(buf, TIPC_ERR_NO_NODE);
1088         return res;
1089 }
1090
1091
1092 /*
1093  * tipc_link_send_sections_fast: Entry for messages where the
1094  * destination processor is known and the header is complete,
1095  * except for total message length.
1096  * Returns user data length or errno.
1097  */
1098 int tipc_link_send_sections_fast(struct tipc_port *sender,
1099                                  struct iovec const *msg_sect,
1100                                  const u32 num_sect,
1101                                  unsigned int total_len,
1102                                  u32 destaddr)
1103 {
1104         struct tipc_msg *hdr = &sender->phdr;
1105         struct tipc_link *l_ptr;
1106         struct sk_buff *buf;
1107         struct tipc_node *node;
1108         int res;
1109         u32 selector = msg_origport(hdr) & 1;
1110
1111 again:
1112         /*
1113          * Try building message using port's max_pkt hint.
1114          * (Must not hold any locks while building message.)
1115          */
1116
1117         res = tipc_msg_build(hdr, msg_sect, num_sect, total_len,
1118                              sender->max_pkt, !sender->user_port, &buf);
1119
1120         read_lock_bh(&tipc_net_lock);
1121         node = tipc_node_find(destaddr);
1122         if (likely(node)) {
1123                 tipc_node_lock(node);
1124                 l_ptr = node->active_links[selector];
1125                 if (likely(l_ptr)) {
1126                         if (likely(buf)) {
1127                                 res = link_send_buf_fast(l_ptr, buf,
1128                                                          &sender->max_pkt);
1129 exit:
1130                                 tipc_node_unlock(node);
1131                                 read_unlock_bh(&tipc_net_lock);
1132                                 return res;
1133                         }
1134
1135                         /* Exit if build request was invalid */
1136
1137                         if (unlikely(res < 0))
1138                                 goto exit;
1139
1140                         /* Exit if link (or bearer) is congested */
1141
1142                         if (link_congested(l_ptr) ||
1143                             !list_empty(&l_ptr->b_ptr->cong_links)) {
1144                                 res = link_schedule_port(l_ptr,
1145                                                          sender->ref, res);
1146                                 goto exit;
1147                         }
1148
1149                         /*
1150                          * Message size exceeds max_pkt hint; update hint,
1151                          * then re-try fast path or fragment the message
1152                          */
1153
1154                         sender->max_pkt = l_ptr->max_pkt;
1155                         tipc_node_unlock(node);
1156                         read_unlock_bh(&tipc_net_lock);
1157
1158
1159                         if ((msg_hdr_sz(hdr) + res) <= sender->max_pkt)
1160                                 goto again;
1161
1162                         return link_send_sections_long(sender, msg_sect,
1163                                                        num_sect, total_len,
1164                                                        destaddr);
1165                 }
1166                 tipc_node_unlock(node);
1167         }
1168         read_unlock_bh(&tipc_net_lock);
1169
1170         /* Couldn't find a link to the destination node */
1171
1172         if (buf)
1173                 return tipc_reject_msg(buf, TIPC_ERR_NO_NODE);
1174         if (res >= 0)
1175                 return tipc_port_reject_sections(sender, hdr, msg_sect, num_sect,
1176                                                  total_len, TIPC_ERR_NO_NODE);
1177         return res;
1178 }
1179
1180 /*
1181  * link_send_sections_long(): Entry for long messages where the
1182  * destination node is known and the header is complete,
1183  * inclusive total message length.
1184  * Link and bearer congestion status have been checked to be ok,
1185  * and are ignored if they change.
1186  *
1187  * Note that fragments do not use the full link MTU so that they won't have
1188  * to undergo refragmentation if link changeover causes them to be sent
1189  * over another link with an additional tunnel header added as prefix.
1190  * (Refragmentation will still occur if the other link has a smaller MTU.)
1191  *
1192  * Returns user data length or errno.
1193  */
1194 static int link_send_sections_long(struct tipc_port *sender,
1195                                    struct iovec const *msg_sect,
1196                                    u32 num_sect,
1197                                    unsigned int total_len,
1198                                    u32 destaddr)
1199 {
1200         struct tipc_link *l_ptr;
1201         struct tipc_node *node;
1202         struct tipc_msg *hdr = &sender->phdr;
1203         u32 dsz = total_len;
1204         u32 max_pkt, fragm_sz, rest;
1205         struct tipc_msg fragm_hdr;
1206         struct sk_buff *buf, *buf_chain, *prev;
1207         u32 fragm_crs, fragm_rest, hsz, sect_rest;
1208         const unchar *sect_crs;
1209         int curr_sect;
1210         u32 fragm_no;
1211
1212 again:
1213         fragm_no = 1;
1214         max_pkt = sender->max_pkt - INT_H_SIZE;
1215                 /* leave room for tunnel header in case of link changeover */
1216         fragm_sz = max_pkt - INT_H_SIZE;
1217                 /* leave room for fragmentation header in each fragment */
1218         rest = dsz;
1219         fragm_crs = 0;
1220         fragm_rest = 0;
1221         sect_rest = 0;
1222         sect_crs = NULL;
1223         curr_sect = -1;
1224
1225         /* Prepare reusable fragment header: */
1226
1227         tipc_msg_init(&fragm_hdr, MSG_FRAGMENTER, FIRST_FRAGMENT,
1228                  INT_H_SIZE, msg_destnode(hdr));
1229         msg_set_size(&fragm_hdr, max_pkt);
1230         msg_set_fragm_no(&fragm_hdr, 1);
1231
1232         /* Prepare header of first fragment: */
1233
1234         buf_chain = buf = tipc_buf_acquire(max_pkt);
1235         if (!buf)
1236                 return -ENOMEM;
1237         buf->next = NULL;
1238         skb_copy_to_linear_data(buf, &fragm_hdr, INT_H_SIZE);
1239         hsz = msg_hdr_sz(hdr);
1240         skb_copy_to_linear_data_offset(buf, INT_H_SIZE, hdr, hsz);
1241
1242         /* Chop up message: */
1243
1244         fragm_crs = INT_H_SIZE + hsz;
1245         fragm_rest = fragm_sz - hsz;
1246
1247         do {            /* For all sections */
1248                 u32 sz;
1249
1250                 if (!sect_rest) {
1251                         sect_rest = msg_sect[++curr_sect].iov_len;
1252                         sect_crs = (const unchar *)msg_sect[curr_sect].iov_base;
1253                 }
1254
1255                 if (sect_rest < fragm_rest)
1256                         sz = sect_rest;
1257                 else
1258                         sz = fragm_rest;
1259
1260                 if (likely(!sender->user_port)) {
1261                         if (copy_from_user(buf->data + fragm_crs, sect_crs, sz)) {
1262 error:
1263                                 for (; buf_chain; buf_chain = buf) {
1264                                         buf = buf_chain->next;
1265                                         buf_discard(buf_chain);
1266                                 }
1267                                 return -EFAULT;
1268                         }
1269                 } else
1270                         skb_copy_to_linear_data_offset(buf, fragm_crs,
1271                                                        sect_crs, sz);
1272                 sect_crs += sz;
1273                 sect_rest -= sz;
1274                 fragm_crs += sz;
1275                 fragm_rest -= sz;
1276                 rest -= sz;
1277
1278                 if (!fragm_rest && rest) {
1279
1280                         /* Initiate new fragment: */
1281                         if (rest <= fragm_sz) {
1282                                 fragm_sz = rest;
1283                                 msg_set_type(&fragm_hdr, LAST_FRAGMENT);
1284                         } else {
1285                                 msg_set_type(&fragm_hdr, FRAGMENT);
1286                         }
1287                         msg_set_size(&fragm_hdr, fragm_sz + INT_H_SIZE);
1288                         msg_set_fragm_no(&fragm_hdr, ++fragm_no);
1289                         prev = buf;
1290                         buf = tipc_buf_acquire(fragm_sz + INT_H_SIZE);
1291                         if (!buf)
1292                                 goto error;
1293
1294                         buf->next = NULL;
1295                         prev->next = buf;
1296                         skb_copy_to_linear_data(buf, &fragm_hdr, INT_H_SIZE);
1297                         fragm_crs = INT_H_SIZE;
1298                         fragm_rest = fragm_sz;
1299                 }
1300         } while (rest > 0);
1301
1302         /*
1303          * Now we have a buffer chain. Select a link and check
1304          * that packet size is still OK
1305          */
1306         node = tipc_node_find(destaddr);
1307         if (likely(node)) {
1308                 tipc_node_lock(node);
1309                 l_ptr = node->active_links[sender->ref & 1];
1310                 if (!l_ptr) {
1311                         tipc_node_unlock(node);
1312                         goto reject;
1313                 }
1314                 if (l_ptr->max_pkt < max_pkt) {
1315                         sender->max_pkt = l_ptr->max_pkt;
1316                         tipc_node_unlock(node);
1317                         for (; buf_chain; buf_chain = buf) {
1318                                 buf = buf_chain->next;
1319                                 buf_discard(buf_chain);
1320                         }
1321                         goto again;
1322                 }
1323         } else {
1324 reject:
1325                 for (; buf_chain; buf_chain = buf) {
1326                         buf = buf_chain->next;
1327                         buf_discard(buf_chain);
1328                 }
1329                 return tipc_port_reject_sections(sender, hdr, msg_sect, num_sect,
1330                                                  total_len, TIPC_ERR_NO_NODE);
1331         }
1332
1333         /* Append chain of fragments to send queue & send them */
1334
1335         l_ptr->long_msg_seq_no++;
1336         link_add_chain_to_outqueue(l_ptr, buf_chain, l_ptr->long_msg_seq_no);
1337         l_ptr->stats.sent_fragments += fragm_no;
1338         l_ptr->stats.sent_fragmented++;
1339         tipc_link_push_queue(l_ptr);
1340         tipc_node_unlock(node);
1341         return dsz;
1342 }
1343
1344 /*
1345  * tipc_link_push_packet: Push one unsent packet to the media
1346  */
1347 u32 tipc_link_push_packet(struct tipc_link *l_ptr)
1348 {
1349         struct sk_buff *buf = l_ptr->first_out;
1350         u32 r_q_size = l_ptr->retransm_queue_size;
1351         u32 r_q_head = l_ptr->retransm_queue_head;
1352
1353         /* Step to position where retransmission failed, if any,    */
1354         /* consider that buffers may have been released in meantime */
1355
1356         if (r_q_size && buf) {
1357                 u32 last = lesser(mod(r_q_head + r_q_size),
1358                                   link_last_sent(l_ptr));
1359                 u32 first = buf_seqno(buf);
1360
1361                 while (buf && less(first, r_q_head)) {
1362                         first = mod(first + 1);
1363                         buf = buf->next;
1364                 }
1365                 l_ptr->retransm_queue_head = r_q_head = first;
1366                 l_ptr->retransm_queue_size = r_q_size = mod(last - first);
1367         }
1368
1369         /* Continue retransmission now, if there is anything: */
1370
1371         if (r_q_size && buf) {
1372                 msg_set_ack(buf_msg(buf), mod(l_ptr->next_in_no - 1));
1373                 msg_set_bcast_ack(buf_msg(buf), l_ptr->owner->bclink.last_in);
1374                 if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1375                         l_ptr->retransm_queue_head = mod(++r_q_head);
1376                         l_ptr->retransm_queue_size = --r_q_size;
1377                         l_ptr->stats.retransmitted++;
1378                         return 0;
1379                 } else {
1380                         l_ptr->stats.bearer_congs++;
1381                         return PUSH_FAILED;
1382                 }
1383         }
1384
1385         /* Send deferred protocol message, if any: */
1386
1387         buf = l_ptr->proto_msg_queue;
1388         if (buf) {
1389                 msg_set_ack(buf_msg(buf), mod(l_ptr->next_in_no - 1));
1390                 msg_set_bcast_ack(buf_msg(buf), l_ptr->owner->bclink.last_in);
1391                 if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1392                         l_ptr->unacked_window = 0;
1393                         buf_discard(buf);
1394                         l_ptr->proto_msg_queue = NULL;
1395                         return 0;
1396                 } else {
1397                         l_ptr->stats.bearer_congs++;
1398                         return PUSH_FAILED;
1399                 }
1400         }
1401
1402         /* Send one deferred data message, if send window not full: */
1403
1404         buf = l_ptr->next_out;
1405         if (buf) {
1406                 struct tipc_msg *msg = buf_msg(buf);
1407                 u32 next = msg_seqno(msg);
1408                 u32 first = buf_seqno(l_ptr->first_out);
1409
1410                 if (mod(next - first) < l_ptr->queue_limit[0]) {
1411                         msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1412                         msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1413                         if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1414                                 if (msg_user(msg) == MSG_BUNDLER)
1415                                         msg_set_type(msg, CLOSED_MSG);
1416                                 l_ptr->next_out = buf->next;
1417                                 return 0;
1418                         } else {
1419                                 l_ptr->stats.bearer_congs++;
1420                                 return PUSH_FAILED;
1421                         }
1422                 }
1423         }
1424         return PUSH_FINISHED;
1425 }
1426
1427 /*
1428  * push_queue(): push out the unsent messages of a link where
1429  *               congestion has abated. Node is locked
1430  */
1431 void tipc_link_push_queue(struct tipc_link *l_ptr)
1432 {
1433         u32 res;
1434
1435         if (tipc_bearer_congested(l_ptr->b_ptr, l_ptr))
1436                 return;
1437
1438         do {
1439                 res = tipc_link_push_packet(l_ptr);
1440         } while (!res);
1441
1442         if (res == PUSH_FAILED)
1443                 tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
1444 }
1445
1446 static void link_reset_all(unsigned long addr)
1447 {
1448         struct tipc_node *n_ptr;
1449         char addr_string[16];
1450         u32 i;
1451
1452         read_lock_bh(&tipc_net_lock);
1453         n_ptr = tipc_node_find((u32)addr);
1454         if (!n_ptr) {
1455                 read_unlock_bh(&tipc_net_lock);
1456                 return; /* node no longer exists */
1457         }
1458
1459         tipc_node_lock(n_ptr);
1460
1461         warn("Resetting all links to %s\n",
1462              tipc_addr_string_fill(addr_string, n_ptr->addr));
1463
1464         for (i = 0; i < MAX_BEARERS; i++) {
1465                 if (n_ptr->links[i]) {
1466                         link_print(n_ptr->links[i], "Resetting link\n");
1467                         tipc_link_reset(n_ptr->links[i]);
1468                 }
1469         }
1470
1471         tipc_node_unlock(n_ptr);
1472         read_unlock_bh(&tipc_net_lock);
1473 }
1474
1475 static void link_retransmit_failure(struct tipc_link *l_ptr,
1476                                         struct sk_buff *buf)
1477 {
1478         struct tipc_msg *msg = buf_msg(buf);
1479
1480         warn("Retransmission failure on link <%s>\n", l_ptr->name);
1481
1482         if (l_ptr->addr) {
1483
1484                 /* Handle failure on standard link */
1485
1486                 link_print(l_ptr, "Resetting link\n");
1487                 tipc_link_reset(l_ptr);
1488
1489         } else {
1490
1491                 /* Handle failure on broadcast link */
1492
1493                 struct tipc_node *n_ptr;
1494                 char addr_string[16];
1495
1496                 info("Msg seq number: %u,  ", msg_seqno(msg));
1497                 info("Outstanding acks: %lu\n",
1498                      (unsigned long) TIPC_SKB_CB(buf)->handle);
1499
1500                 n_ptr = tipc_bclink_retransmit_to();
1501                 tipc_node_lock(n_ptr);
1502
1503                 tipc_addr_string_fill(addr_string, n_ptr->addr);
1504                 info("Multicast link info for %s\n", addr_string);
1505                 info("Supported: %d,  ", n_ptr->bclink.supported);
1506                 info("Acked: %u\n", n_ptr->bclink.acked);
1507                 info("Last in: %u,  ", n_ptr->bclink.last_in);
1508                 info("Gap after: %u,  ", n_ptr->bclink.gap_after);
1509                 info("Gap to: %u\n", n_ptr->bclink.gap_to);
1510                 info("Nack sync: %u\n\n", n_ptr->bclink.nack_sync);
1511
1512                 tipc_k_signal((Handler)link_reset_all, (unsigned long)n_ptr->addr);
1513
1514                 tipc_node_unlock(n_ptr);
1515
1516                 l_ptr->stale_count = 0;
1517         }
1518 }
1519
1520 void tipc_link_retransmit(struct tipc_link *l_ptr, struct sk_buff *buf,
1521                           u32 retransmits)
1522 {
1523         struct tipc_msg *msg;
1524
1525         if (!buf)
1526                 return;
1527
1528         msg = buf_msg(buf);
1529
1530         if (tipc_bearer_congested(l_ptr->b_ptr, l_ptr)) {
1531                 if (l_ptr->retransm_queue_size == 0) {
1532                         l_ptr->retransm_queue_head = msg_seqno(msg);
1533                         l_ptr->retransm_queue_size = retransmits;
1534                 } else {
1535                         err("Unexpected retransmit on link %s (qsize=%d)\n",
1536                             l_ptr->name, l_ptr->retransm_queue_size);
1537                 }
1538                 return;
1539         } else {
1540                 /* Detect repeated retransmit failures on uncongested bearer */
1541
1542                 if (l_ptr->last_retransmitted == msg_seqno(msg)) {
1543                         if (++l_ptr->stale_count > 100) {
1544                                 link_retransmit_failure(l_ptr, buf);
1545                                 return;
1546                         }
1547                 } else {
1548                         l_ptr->last_retransmitted = msg_seqno(msg);
1549                         l_ptr->stale_count = 1;
1550                 }
1551         }
1552
1553         while (retransmits && (buf != l_ptr->next_out) && buf) {
1554                 msg = buf_msg(buf);
1555                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1556                 msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1557                 if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1558                         buf = buf->next;
1559                         retransmits--;
1560                         l_ptr->stats.retransmitted++;
1561                 } else {
1562                         tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
1563                         l_ptr->stats.bearer_congs++;
1564                         l_ptr->retransm_queue_head = buf_seqno(buf);
1565                         l_ptr->retransm_queue_size = retransmits;
1566                         return;
1567                 }
1568         }
1569
1570         l_ptr->retransm_queue_head = l_ptr->retransm_queue_size = 0;
1571 }
1572
1573 /**
1574  * link_insert_deferred_queue - insert deferred messages back into receive chain
1575  */
1576
1577 static struct sk_buff *link_insert_deferred_queue(struct tipc_link *l_ptr,
1578                                                   struct sk_buff *buf)
1579 {
1580         u32 seq_no;
1581
1582         if (l_ptr->oldest_deferred_in == NULL)
1583                 return buf;
1584
1585         seq_no = buf_seqno(l_ptr->oldest_deferred_in);
1586         if (seq_no == mod(l_ptr->next_in_no)) {
1587                 l_ptr->newest_deferred_in->next = buf;
1588                 buf = l_ptr->oldest_deferred_in;
1589                 l_ptr->oldest_deferred_in = NULL;
1590                 l_ptr->deferred_inqueue_sz = 0;
1591         }
1592         return buf;
1593 }
1594
1595 /**
1596  * link_recv_buf_validate - validate basic format of received message
1597  *
1598  * This routine ensures a TIPC message has an acceptable header, and at least
1599  * as much data as the header indicates it should.  The routine also ensures
1600  * that the entire message header is stored in the main fragment of the message
1601  * buffer, to simplify future access to message header fields.
1602  *
1603  * Note: Having extra info present in the message header or data areas is OK.
1604  * TIPC will ignore the excess, under the assumption that it is optional info
1605  * introduced by a later release of the protocol.
1606  */
1607
1608 static int link_recv_buf_validate(struct sk_buff *buf)
1609 {
1610         static u32 min_data_hdr_size[8] = {
1611                 SHORT_H_SIZE, MCAST_H_SIZE, NAMED_H_SIZE, BASIC_H_SIZE,
1612                 MAX_H_SIZE, MAX_H_SIZE, MAX_H_SIZE, MAX_H_SIZE
1613                 };
1614
1615         struct tipc_msg *msg;
1616         u32 tipc_hdr[2];
1617         u32 size;
1618         u32 hdr_size;
1619         u32 min_hdr_size;
1620
1621         if (unlikely(buf->len < MIN_H_SIZE))
1622                 return 0;
1623
1624         msg = skb_header_pointer(buf, 0, sizeof(tipc_hdr), tipc_hdr);
1625         if (msg == NULL)
1626                 return 0;
1627
1628         if (unlikely(msg_version(msg) != TIPC_VERSION))
1629                 return 0;
1630
1631         size = msg_size(msg);
1632         hdr_size = msg_hdr_sz(msg);
1633         min_hdr_size = msg_isdata(msg) ?
1634                 min_data_hdr_size[msg_type(msg)] : INT_H_SIZE;
1635
1636         if (unlikely((hdr_size < min_hdr_size) ||
1637                      (size < hdr_size) ||
1638                      (buf->len < size) ||
1639                      (size - hdr_size > TIPC_MAX_USER_MSG_SIZE)))
1640                 return 0;
1641
1642         return pskb_may_pull(buf, hdr_size);
1643 }
1644
1645 /**
1646  * tipc_recv_msg - process TIPC messages arriving from off-node
1647  * @head: pointer to message buffer chain
1648  * @tb_ptr: pointer to bearer message arrived on
1649  *
1650  * Invoked with no locks held.  Bearer pointer must point to a valid bearer
1651  * structure (i.e. cannot be NULL), but bearer can be inactive.
1652  */
1653
1654 void tipc_recv_msg(struct sk_buff *head, struct tipc_bearer *b_ptr)
1655 {
1656         read_lock_bh(&tipc_net_lock);
1657         while (head) {
1658                 struct tipc_node *n_ptr;
1659                 struct tipc_link *l_ptr;
1660                 struct sk_buff *crs;
1661                 struct sk_buff *buf = head;
1662                 struct tipc_msg *msg;
1663                 u32 seq_no;
1664                 u32 ackd;
1665                 u32 released = 0;
1666                 int type;
1667
1668                 head = head->next;
1669
1670                 /* Ensure bearer is still enabled */
1671
1672                 if (unlikely(!b_ptr->active))
1673                         goto cont;
1674
1675                 /* Ensure message is well-formed */
1676
1677                 if (unlikely(!link_recv_buf_validate(buf)))
1678                         goto cont;
1679
1680                 /* Ensure message data is a single contiguous unit */
1681
1682                 if (unlikely(buf_linearize(buf)))
1683                         goto cont;
1684
1685                 /* Handle arrival of a non-unicast link message */
1686
1687                 msg = buf_msg(buf);
1688
1689                 if (unlikely(msg_non_seq(msg))) {
1690                         if (msg_user(msg) ==  LINK_CONFIG)
1691                                 tipc_disc_recv_msg(buf, b_ptr);
1692                         else
1693                                 tipc_bclink_recv_pkt(buf);
1694                         continue;
1695                 }
1696
1697                 /* Discard unicast link messages destined for another node */
1698
1699                 if (unlikely(!msg_short(msg) &&
1700                              (msg_destnode(msg) != tipc_own_addr)))
1701                         goto cont;
1702
1703                 /* Locate neighboring node that sent message */
1704
1705                 n_ptr = tipc_node_find(msg_prevnode(msg));
1706                 if (unlikely(!n_ptr))
1707                         goto cont;
1708                 tipc_node_lock(n_ptr);
1709
1710                 /* Locate unicast link endpoint that should handle message */
1711
1712                 l_ptr = n_ptr->links[b_ptr->identity];
1713                 if (unlikely(!l_ptr)) {
1714                         tipc_node_unlock(n_ptr);
1715                         goto cont;
1716                 }
1717
1718                 /* Verify that communication with node is currently allowed */
1719
1720                 if ((n_ptr->block_setup & WAIT_PEER_DOWN) &&
1721                         msg_user(msg) == LINK_PROTOCOL &&
1722                         (msg_type(msg) == RESET_MSG ||
1723                                         msg_type(msg) == ACTIVATE_MSG) &&
1724                         !msg_redundant_link(msg))
1725                         n_ptr->block_setup &= ~WAIT_PEER_DOWN;
1726
1727                 if (n_ptr->block_setup) {
1728                         tipc_node_unlock(n_ptr);
1729                         goto cont;
1730                 }
1731
1732                 /* Validate message sequence number info */
1733
1734                 seq_no = msg_seqno(msg);
1735                 ackd = msg_ack(msg);
1736
1737                 /* Release acked messages */
1738
1739                 if (tipc_node_is_up(n_ptr) && n_ptr->bclink.supported)
1740                         tipc_bclink_acknowledge(n_ptr, msg_bcast_ack(msg));
1741
1742                 crs = l_ptr->first_out;
1743                 while ((crs != l_ptr->next_out) &&
1744                        less_eq(buf_seqno(crs), ackd)) {
1745                         struct sk_buff *next = crs->next;
1746
1747                         buf_discard(crs);
1748                         crs = next;
1749                         released++;
1750                 }
1751                 if (released) {
1752                         l_ptr->first_out = crs;
1753                         l_ptr->out_queue_size -= released;
1754                 }
1755
1756                 /* Try sending any messages link endpoint has pending */
1757
1758                 if (unlikely(l_ptr->next_out))
1759                         tipc_link_push_queue(l_ptr);
1760                 if (unlikely(!list_empty(&l_ptr->waiting_ports)))
1761                         tipc_link_wakeup_ports(l_ptr, 0);
1762                 if (unlikely(++l_ptr->unacked_window >= TIPC_MIN_LINK_WIN)) {
1763                         l_ptr->stats.sent_acks++;
1764                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
1765                 }
1766
1767                 /* Now (finally!) process the incoming message */
1768
1769 protocol_check:
1770                 if (likely(link_working_working(l_ptr))) {
1771                         if (likely(seq_no == mod(l_ptr->next_in_no))) {
1772                                 l_ptr->next_in_no++;
1773                                 if (unlikely(l_ptr->oldest_deferred_in))
1774                                         head = link_insert_deferred_queue(l_ptr,
1775                                                                           head);
1776                                 if (likely(msg_is_dest(msg, tipc_own_addr))) {
1777 deliver:
1778                                         if (likely(msg_isdata(msg))) {
1779                                                 tipc_node_unlock(n_ptr);
1780                                                 tipc_port_recv_msg(buf);
1781                                                 continue;
1782                                         }
1783                                         switch (msg_user(msg)) {
1784                                         case MSG_BUNDLER:
1785                                                 l_ptr->stats.recv_bundles++;
1786                                                 l_ptr->stats.recv_bundled +=
1787                                                         msg_msgcnt(msg);
1788                                                 tipc_node_unlock(n_ptr);
1789                                                 tipc_link_recv_bundle(buf);
1790                                                 continue;
1791                                         case NAME_DISTRIBUTOR:
1792                                                 tipc_node_unlock(n_ptr);
1793                                                 tipc_named_recv(buf);
1794                                                 continue;
1795                                         case CONN_MANAGER:
1796                                                 tipc_node_unlock(n_ptr);
1797                                                 tipc_port_recv_proto_msg(buf);
1798                                                 continue;
1799                                         case MSG_FRAGMENTER:
1800                                                 l_ptr->stats.recv_fragments++;
1801                                                 if (tipc_link_recv_fragment(&l_ptr->defragm_buf,
1802                                                                             &buf, &msg)) {
1803                                                         l_ptr->stats.recv_fragmented++;
1804                                                         goto deliver;
1805                                                 }
1806                                                 break;
1807                                         case CHANGEOVER_PROTOCOL:
1808                                                 type = msg_type(msg);
1809                                                 if (link_recv_changeover_msg(&l_ptr, &buf)) {
1810                                                         msg = buf_msg(buf);
1811                                                         seq_no = msg_seqno(msg);
1812                                                         if (type == ORIGINAL_MSG)
1813                                                                 goto deliver;
1814                                                         goto protocol_check;
1815                                                 }
1816                                                 break;
1817                                         default:
1818                                                 buf_discard(buf);
1819                                                 buf = NULL;
1820                                                 break;
1821                                         }
1822                                 }
1823                                 tipc_node_unlock(n_ptr);
1824                                 tipc_net_route_msg(buf);
1825                                 continue;
1826                         }
1827                         link_handle_out_of_seq_msg(l_ptr, buf);
1828                         head = link_insert_deferred_queue(l_ptr, head);
1829                         tipc_node_unlock(n_ptr);
1830                         continue;
1831                 }
1832
1833                 if (msg_user(msg) == LINK_PROTOCOL) {
1834                         link_recv_proto_msg(l_ptr, buf);
1835                         head = link_insert_deferred_queue(l_ptr, head);
1836                         tipc_node_unlock(n_ptr);
1837                         continue;
1838                 }
1839                 link_state_event(l_ptr, TRAFFIC_MSG_EVT);
1840
1841                 if (link_working_working(l_ptr)) {
1842                         /* Re-insert in front of queue */
1843                         buf->next = head;
1844                         head = buf;
1845                         tipc_node_unlock(n_ptr);
1846                         continue;
1847                 }
1848                 tipc_node_unlock(n_ptr);
1849 cont:
1850                 buf_discard(buf);
1851         }
1852         read_unlock_bh(&tipc_net_lock);
1853 }
1854
1855 /*
1856  * link_defer_buf(): Sort a received out-of-sequence packet
1857  *                   into the deferred reception queue.
1858  * Returns the increase of the queue length,i.e. 0 or 1
1859  */
1860
1861 u32 tipc_link_defer_pkt(struct sk_buff **head,
1862                         struct sk_buff **tail,
1863                         struct sk_buff *buf)
1864 {
1865         struct sk_buff *prev = NULL;
1866         struct sk_buff *crs = *head;
1867         u32 seq_no = buf_seqno(buf);
1868
1869         buf->next = NULL;
1870
1871         /* Empty queue ? */
1872         if (*head == NULL) {
1873                 *head = *tail = buf;
1874                 return 1;
1875         }
1876
1877         /* Last ? */
1878         if (less(buf_seqno(*tail), seq_no)) {
1879                 (*tail)->next = buf;
1880                 *tail = buf;
1881                 return 1;
1882         }
1883
1884         /* Scan through queue and sort it in */
1885         do {
1886                 struct tipc_msg *msg = buf_msg(crs);
1887
1888                 if (less(seq_no, msg_seqno(msg))) {
1889                         buf->next = crs;
1890                         if (prev)
1891                                 prev->next = buf;
1892                         else
1893                                 *head = buf;
1894                         return 1;
1895                 }
1896                 if (seq_no == msg_seqno(msg))
1897                         break;
1898                 prev = crs;
1899                 crs = crs->next;
1900         } while (crs);
1901
1902         /* Message is a duplicate of an existing message */
1903
1904         buf_discard(buf);
1905         return 0;
1906 }
1907
1908 /**
1909  * link_handle_out_of_seq_msg - handle arrival of out-of-sequence packet
1910  */
1911
1912 static void link_handle_out_of_seq_msg(struct tipc_link *l_ptr,
1913                                        struct sk_buff *buf)
1914 {
1915         u32 seq_no = buf_seqno(buf);
1916
1917         if (likely(msg_user(buf_msg(buf)) == LINK_PROTOCOL)) {
1918                 link_recv_proto_msg(l_ptr, buf);
1919                 return;
1920         }
1921
1922         /* Record OOS packet arrival (force mismatch on next timeout) */
1923
1924         l_ptr->checkpoint--;
1925
1926         /*
1927          * Discard packet if a duplicate; otherwise add it to deferred queue
1928          * and notify peer of gap as per protocol specification
1929          */
1930
1931         if (less(seq_no, mod(l_ptr->next_in_no))) {
1932                 l_ptr->stats.duplicates++;
1933                 buf_discard(buf);
1934                 return;
1935         }
1936
1937         if (tipc_link_defer_pkt(&l_ptr->oldest_deferred_in,
1938                                 &l_ptr->newest_deferred_in, buf)) {
1939                 l_ptr->deferred_inqueue_sz++;
1940                 l_ptr->stats.deferred_recv++;
1941                 if ((l_ptr->deferred_inqueue_sz % 16) == 1)
1942                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
1943         } else
1944                 l_ptr->stats.duplicates++;
1945 }
1946
1947 /*
1948  * Send protocol message to the other endpoint.
1949  */
1950 void tipc_link_send_proto_msg(struct tipc_link *l_ptr, u32 msg_typ,
1951                                 int probe_msg, u32 gap, u32 tolerance,
1952                                 u32 priority, u32 ack_mtu)
1953 {
1954         struct sk_buff *buf = NULL;
1955         struct tipc_msg *msg = l_ptr->pmsg;
1956         u32 msg_size = sizeof(l_ptr->proto_msg);
1957         int r_flag;
1958
1959         if (link_blocked(l_ptr))
1960                 return;
1961
1962         /* Abort non-RESET send if communication with node is prohibited */
1963
1964         if ((l_ptr->owner->block_setup) && (msg_typ != RESET_MSG))
1965                 return;
1966
1967         msg_set_type(msg, msg_typ);
1968         msg_set_net_plane(msg, l_ptr->b_ptr->net_plane);
1969         msg_set_bcast_ack(msg, mod(l_ptr->owner->bclink.last_in));
1970         msg_set_last_bcast(msg, tipc_bclink_get_last_sent());
1971
1972         if (msg_typ == STATE_MSG) {
1973                 u32 next_sent = mod(l_ptr->next_out_no);
1974
1975                 if (!tipc_link_is_up(l_ptr))
1976                         return;
1977                 if (l_ptr->next_out)
1978                         next_sent = buf_seqno(l_ptr->next_out);
1979                 msg_set_next_sent(msg, next_sent);
1980                 if (l_ptr->oldest_deferred_in) {
1981                         u32 rec = buf_seqno(l_ptr->oldest_deferred_in);
1982                         gap = mod(rec - mod(l_ptr->next_in_no));
1983                 }
1984                 msg_set_seq_gap(msg, gap);
1985                 if (gap)
1986                         l_ptr->stats.sent_nacks++;
1987                 msg_set_link_tolerance(msg, tolerance);
1988                 msg_set_linkprio(msg, priority);
1989                 msg_set_max_pkt(msg, ack_mtu);
1990                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1991                 msg_set_probe(msg, probe_msg != 0);
1992                 if (probe_msg) {
1993                         u32 mtu = l_ptr->max_pkt;
1994
1995                         if ((mtu < l_ptr->max_pkt_target) &&
1996                             link_working_working(l_ptr) &&
1997                             l_ptr->fsm_msg_cnt) {
1998                                 msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
1999                                 if (l_ptr->max_pkt_probes == 10) {
2000                                         l_ptr->max_pkt_target = (msg_size - 4);
2001                                         l_ptr->max_pkt_probes = 0;
2002                                         msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
2003                                 }
2004                                 l_ptr->max_pkt_probes++;
2005                         }
2006
2007                         l_ptr->stats.sent_probes++;
2008                 }
2009                 l_ptr->stats.sent_states++;
2010         } else {                /* RESET_MSG or ACTIVATE_MSG */
2011                 msg_set_ack(msg, mod(l_ptr->reset_checkpoint - 1));
2012                 msg_set_seq_gap(msg, 0);
2013                 msg_set_next_sent(msg, 1);
2014                 msg_set_probe(msg, 0);
2015                 msg_set_link_tolerance(msg, l_ptr->tolerance);
2016                 msg_set_linkprio(msg, l_ptr->priority);
2017                 msg_set_max_pkt(msg, l_ptr->max_pkt_target);
2018         }
2019
2020         r_flag = (l_ptr->owner->working_links > tipc_link_is_up(l_ptr));
2021         msg_set_redundant_link(msg, r_flag);
2022         msg_set_linkprio(msg, l_ptr->priority);
2023
2024         /* Ensure sequence number will not fit : */
2025
2026         msg_set_seqno(msg, mod(l_ptr->next_out_no + (0xffff/2)));
2027
2028         /* Congestion? */
2029
2030         if (tipc_bearer_congested(l_ptr->b_ptr, l_ptr)) {
2031                 if (!l_ptr->proto_msg_queue) {
2032                         l_ptr->proto_msg_queue =
2033                                 tipc_buf_acquire(sizeof(l_ptr->proto_msg));
2034                 }
2035                 buf = l_ptr->proto_msg_queue;
2036                 if (!buf)
2037                         return;
2038                 skb_copy_to_linear_data(buf, msg, sizeof(l_ptr->proto_msg));
2039                 return;
2040         }
2041
2042         /* Message can be sent */
2043
2044         buf = tipc_buf_acquire(msg_size);
2045         if (!buf)
2046                 return;
2047
2048         skb_copy_to_linear_data(buf, msg, sizeof(l_ptr->proto_msg));
2049         msg_set_size(buf_msg(buf), msg_size);
2050
2051         if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
2052                 l_ptr->unacked_window = 0;
2053                 buf_discard(buf);
2054                 return;
2055         }
2056
2057         /* New congestion */
2058         tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
2059         l_ptr->proto_msg_queue = buf;
2060         l_ptr->stats.bearer_congs++;
2061 }
2062
2063 /*
2064  * Receive protocol message :
2065  * Note that network plane id propagates through the network, and may
2066  * change at any time. The node with lowest address rules
2067  */
2068
2069 static void link_recv_proto_msg(struct tipc_link *l_ptr, struct sk_buff *buf)
2070 {
2071         u32 rec_gap = 0;
2072         u32 max_pkt_info;
2073         u32 max_pkt_ack;
2074         u32 msg_tol;
2075         struct tipc_msg *msg = buf_msg(buf);
2076
2077         if (link_blocked(l_ptr))
2078                 goto exit;
2079
2080         /* record unnumbered packet arrival (force mismatch on next timeout) */
2081
2082         l_ptr->checkpoint--;
2083
2084         if (l_ptr->b_ptr->net_plane != msg_net_plane(msg))
2085                 if (tipc_own_addr > msg_prevnode(msg))
2086                         l_ptr->b_ptr->net_plane = msg_net_plane(msg);
2087
2088         l_ptr->owner->permit_changeover = msg_redundant_link(msg);
2089
2090         switch (msg_type(msg)) {
2091
2092         case RESET_MSG:
2093                 if (!link_working_unknown(l_ptr) &&
2094                     (l_ptr->peer_session != INVALID_SESSION)) {
2095                         if (less_eq(msg_session(msg), l_ptr->peer_session))
2096                                 break; /* duplicate or old reset: ignore */
2097                 }
2098
2099                 if (!msg_redundant_link(msg) && (link_working_working(l_ptr) ||
2100                                 link_working_unknown(l_ptr))) {
2101                         /*
2102                          * peer has lost contact -- don't allow peer's links
2103                          * to reactivate before we recognize loss & clean up
2104                          */
2105                         l_ptr->owner->block_setup = WAIT_NODE_DOWN;
2106                 }
2107
2108                 /* fall thru' */
2109         case ACTIVATE_MSG:
2110                 /* Update link settings according other endpoint's values */
2111
2112                 strcpy((strrchr(l_ptr->name, ':') + 1), (char *)msg_data(msg));
2113
2114                 msg_tol = msg_link_tolerance(msg);
2115                 if (msg_tol > l_ptr->tolerance)
2116                         link_set_supervision_props(l_ptr, msg_tol);
2117
2118                 if (msg_linkprio(msg) > l_ptr->priority)
2119                         l_ptr->priority = msg_linkprio(msg);
2120
2121                 max_pkt_info = msg_max_pkt(msg);
2122                 if (max_pkt_info) {
2123                         if (max_pkt_info < l_ptr->max_pkt_target)
2124                                 l_ptr->max_pkt_target = max_pkt_info;
2125                         if (l_ptr->max_pkt > l_ptr->max_pkt_target)
2126                                 l_ptr->max_pkt = l_ptr->max_pkt_target;
2127                 } else {
2128                         l_ptr->max_pkt = l_ptr->max_pkt_target;
2129                 }
2130                 l_ptr->owner->bclink.supported = (max_pkt_info != 0);
2131
2132                 link_state_event(l_ptr, msg_type(msg));
2133
2134                 l_ptr->peer_session = msg_session(msg);
2135                 l_ptr->peer_bearer_id = msg_bearer_id(msg);
2136
2137                 /* Synchronize broadcast sequence numbers */
2138                 if (!tipc_node_redundant_links(l_ptr->owner))
2139                         l_ptr->owner->bclink.last_in = mod(msg_last_bcast(msg));
2140                 break;
2141         case STATE_MSG:
2142
2143                 msg_tol = msg_link_tolerance(msg);
2144                 if (msg_tol)
2145                         link_set_supervision_props(l_ptr, msg_tol);
2146
2147                 if (msg_linkprio(msg) &&
2148                     (msg_linkprio(msg) != l_ptr->priority)) {
2149                         warn("Resetting link <%s>, priority change %u->%u\n",
2150                              l_ptr->name, l_ptr->priority, msg_linkprio(msg));
2151                         l_ptr->priority = msg_linkprio(msg);
2152                         tipc_link_reset(l_ptr); /* Enforce change to take effect */
2153                         break;
2154                 }
2155                 link_state_event(l_ptr, TRAFFIC_MSG_EVT);
2156                 l_ptr->stats.recv_states++;
2157                 if (link_reset_unknown(l_ptr))
2158                         break;
2159
2160                 if (less_eq(mod(l_ptr->next_in_no), msg_next_sent(msg))) {
2161                         rec_gap = mod(msg_next_sent(msg) -
2162                                       mod(l_ptr->next_in_no));
2163                 }
2164
2165                 max_pkt_ack = msg_max_pkt(msg);
2166                 if (max_pkt_ack > l_ptr->max_pkt) {
2167                         l_ptr->max_pkt = max_pkt_ack;
2168                         l_ptr->max_pkt_probes = 0;
2169                 }
2170
2171                 max_pkt_ack = 0;
2172                 if (msg_probe(msg)) {
2173                         l_ptr->stats.recv_probes++;
2174                         if (msg_size(msg) > sizeof(l_ptr->proto_msg))
2175                                 max_pkt_ack = msg_size(msg);
2176                 }
2177
2178                 /* Protocol message before retransmits, reduce loss risk */
2179
2180                 tipc_bclink_check_gap(l_ptr->owner, msg_last_bcast(msg));
2181
2182                 if (rec_gap || (msg_probe(msg))) {
2183                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
2184                                                  0, rec_gap, 0, 0, max_pkt_ack);
2185                 }
2186                 if (msg_seq_gap(msg)) {
2187                         l_ptr->stats.recv_nacks++;
2188                         tipc_link_retransmit(l_ptr, l_ptr->first_out,
2189                                              msg_seq_gap(msg));
2190                 }
2191                 break;
2192         }
2193 exit:
2194         buf_discard(buf);
2195 }
2196
2197
2198 /*
2199  * tipc_link_tunnel(): Send one message via a link belonging to
2200  * another bearer. Owner node is locked.
2201  */
2202 static void tipc_link_tunnel(struct tipc_link *l_ptr,
2203                              struct tipc_msg *tunnel_hdr,
2204                              struct tipc_msg  *msg,
2205                              u32 selector)
2206 {
2207         struct tipc_link *tunnel;
2208         struct sk_buff *buf;
2209         u32 length = msg_size(msg);
2210
2211         tunnel = l_ptr->owner->active_links[selector & 1];
2212         if (!tipc_link_is_up(tunnel)) {
2213                 warn("Link changeover error, "
2214                      "tunnel link no longer available\n");
2215                 return;
2216         }
2217         msg_set_size(tunnel_hdr, length + INT_H_SIZE);
2218         buf = tipc_buf_acquire(length + INT_H_SIZE);
2219         if (!buf) {
2220                 warn("Link changeover error, "
2221                      "unable to send tunnel msg\n");
2222                 return;
2223         }
2224         skb_copy_to_linear_data(buf, tunnel_hdr, INT_H_SIZE);
2225         skb_copy_to_linear_data_offset(buf, INT_H_SIZE, msg, length);
2226         tipc_link_send_buf(tunnel, buf);
2227 }
2228
2229
2230
2231 /*
2232  * changeover(): Send whole message queue via the remaining link
2233  *               Owner node is locked.
2234  */
2235
2236 void tipc_link_changeover(struct tipc_link *l_ptr)
2237 {
2238         u32 msgcount = l_ptr->out_queue_size;
2239         struct sk_buff *crs = l_ptr->first_out;
2240         struct tipc_link *tunnel = l_ptr->owner->active_links[0];
2241         struct tipc_msg tunnel_hdr;
2242         int split_bundles;
2243
2244         if (!tunnel)
2245                 return;
2246
2247         if (!l_ptr->owner->permit_changeover) {
2248                 warn("Link changeover error, "
2249                      "peer did not permit changeover\n");
2250                 return;
2251         }
2252
2253         tipc_msg_init(&tunnel_hdr, CHANGEOVER_PROTOCOL,
2254                  ORIGINAL_MSG, INT_H_SIZE, l_ptr->addr);
2255         msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
2256         msg_set_msgcnt(&tunnel_hdr, msgcount);
2257
2258         if (!l_ptr->first_out) {
2259                 struct sk_buff *buf;
2260
2261                 buf = tipc_buf_acquire(INT_H_SIZE);
2262                 if (buf) {
2263                         skb_copy_to_linear_data(buf, &tunnel_hdr, INT_H_SIZE);
2264                         msg_set_size(&tunnel_hdr, INT_H_SIZE);
2265                         tipc_link_send_buf(tunnel, buf);
2266                 } else {
2267                         warn("Link changeover error, "
2268                              "unable to send changeover msg\n");
2269                 }
2270                 return;
2271         }
2272
2273         split_bundles = (l_ptr->owner->active_links[0] !=
2274                          l_ptr->owner->active_links[1]);
2275
2276         while (crs) {
2277                 struct tipc_msg *msg = buf_msg(crs);
2278
2279                 if ((msg_user(msg) == MSG_BUNDLER) && split_bundles) {
2280                         struct tipc_msg *m = msg_get_wrapped(msg);
2281                         unchar *pos = (unchar *)m;
2282
2283                         msgcount = msg_msgcnt(msg);
2284                         while (msgcount--) {
2285                                 msg_set_seqno(m, msg_seqno(msg));
2286                                 tipc_link_tunnel(l_ptr, &tunnel_hdr, m,
2287                                                  msg_link_selector(m));
2288                                 pos += align(msg_size(m));
2289                                 m = (struct tipc_msg *)pos;
2290                         }
2291                 } else {
2292                         tipc_link_tunnel(l_ptr, &tunnel_hdr, msg,
2293                                          msg_link_selector(msg));
2294                 }
2295                 crs = crs->next;
2296         }
2297 }
2298
2299 void tipc_link_send_duplicate(struct tipc_link *l_ptr, struct tipc_link *tunnel)
2300 {
2301         struct sk_buff *iter;
2302         struct tipc_msg tunnel_hdr;
2303
2304         tipc_msg_init(&tunnel_hdr, CHANGEOVER_PROTOCOL,
2305                  DUPLICATE_MSG, INT_H_SIZE, l_ptr->addr);
2306         msg_set_msgcnt(&tunnel_hdr, l_ptr->out_queue_size);
2307         msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
2308         iter = l_ptr->first_out;
2309         while (iter) {
2310                 struct sk_buff *outbuf;
2311                 struct tipc_msg *msg = buf_msg(iter);
2312                 u32 length = msg_size(msg);
2313
2314                 if (msg_user(msg) == MSG_BUNDLER)
2315                         msg_set_type(msg, CLOSED_MSG);
2316                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));   /* Update */
2317                 msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
2318                 msg_set_size(&tunnel_hdr, length + INT_H_SIZE);
2319                 outbuf = tipc_buf_acquire(length + INT_H_SIZE);
2320                 if (outbuf == NULL) {
2321                         warn("Link changeover error, "
2322                              "unable to send duplicate msg\n");
2323                         return;
2324                 }
2325                 skb_copy_to_linear_data(outbuf, &tunnel_hdr, INT_H_SIZE);
2326                 skb_copy_to_linear_data_offset(outbuf, INT_H_SIZE, iter->data,
2327                                                length);
2328                 tipc_link_send_buf(tunnel, outbuf);
2329                 if (!tipc_link_is_up(l_ptr))
2330                         return;
2331                 iter = iter->next;
2332         }
2333 }
2334
2335
2336
2337 /**
2338  * buf_extract - extracts embedded TIPC message from another message
2339  * @skb: encapsulating message buffer
2340  * @from_pos: offset to extract from
2341  *
2342  * Returns a new message buffer containing an embedded message.  The
2343  * encapsulating message itself is left unchanged.
2344  */
2345
2346 static struct sk_buff *buf_extract(struct sk_buff *skb, u32 from_pos)
2347 {
2348         struct tipc_msg *msg = (struct tipc_msg *)(skb->data + from_pos);
2349         u32 size = msg_size(msg);
2350         struct sk_buff *eb;
2351
2352         eb = tipc_buf_acquire(size);
2353         if (eb)
2354                 skb_copy_to_linear_data(eb, msg, size);
2355         return eb;
2356 }
2357
2358 /*
2359  *  link_recv_changeover_msg(): Receive tunneled packet sent
2360  *  via other link. Node is locked. Return extracted buffer.
2361  */
2362
2363 static int link_recv_changeover_msg(struct tipc_link **l_ptr,
2364                                     struct sk_buff **buf)
2365 {
2366         struct sk_buff *tunnel_buf = *buf;
2367         struct tipc_link *dest_link;
2368         struct tipc_msg *msg;
2369         struct tipc_msg *tunnel_msg = buf_msg(tunnel_buf);
2370         u32 msg_typ = msg_type(tunnel_msg);
2371         u32 msg_count = msg_msgcnt(tunnel_msg);
2372
2373         dest_link = (*l_ptr)->owner->links[msg_bearer_id(tunnel_msg)];
2374         if (!dest_link)
2375                 goto exit;
2376         if (dest_link == *l_ptr) {
2377                 err("Unexpected changeover message on link <%s>\n",
2378                     (*l_ptr)->name);
2379                 goto exit;
2380         }
2381         *l_ptr = dest_link;
2382         msg = msg_get_wrapped(tunnel_msg);
2383
2384         if (msg_typ == DUPLICATE_MSG) {
2385                 if (less(msg_seqno(msg), mod(dest_link->next_in_no)))
2386                         goto exit;
2387                 *buf = buf_extract(tunnel_buf, INT_H_SIZE);
2388                 if (*buf == NULL) {
2389                         warn("Link changeover error, duplicate msg dropped\n");
2390                         goto exit;
2391                 }
2392                 buf_discard(tunnel_buf);
2393                 return 1;
2394         }
2395
2396         /* First original message ?: */
2397
2398         if (tipc_link_is_up(dest_link)) {
2399                 info("Resetting link <%s>, changeover initiated by peer\n",
2400                      dest_link->name);
2401                 tipc_link_reset(dest_link);
2402                 dest_link->exp_msg_count = msg_count;
2403                 if (!msg_count)
2404                         goto exit;
2405         } else if (dest_link->exp_msg_count == START_CHANGEOVER) {
2406                 dest_link->exp_msg_count = msg_count;
2407                 if (!msg_count)
2408                         goto exit;
2409         }
2410
2411         /* Receive original message */
2412
2413         if (dest_link->exp_msg_count == 0) {
2414                 warn("Link switchover error, "
2415                      "got too many tunnelled messages\n");
2416                 goto exit;
2417         }
2418         dest_link->exp_msg_count--;
2419         if (less(msg_seqno(msg), dest_link->reset_checkpoint)) {
2420                 goto exit;
2421         } else {
2422                 *buf = buf_extract(tunnel_buf, INT_H_SIZE);
2423                 if (*buf != NULL) {
2424                         buf_discard(tunnel_buf);
2425                         return 1;
2426                 } else {
2427                         warn("Link changeover error, original msg dropped\n");
2428                 }
2429         }
2430 exit:
2431         *buf = NULL;
2432         buf_discard(tunnel_buf);
2433         return 0;
2434 }
2435
2436 /*
2437  *  Bundler functionality:
2438  */
2439 void tipc_link_recv_bundle(struct sk_buff *buf)
2440 {
2441         u32 msgcount = msg_msgcnt(buf_msg(buf));
2442         u32 pos = INT_H_SIZE;
2443         struct sk_buff *obuf;
2444
2445         while (msgcount--) {
2446                 obuf = buf_extract(buf, pos);
2447                 if (obuf == NULL) {
2448                         warn("Link unable to unbundle message(s)\n");
2449                         break;
2450                 }
2451                 pos += align(msg_size(buf_msg(obuf)));
2452                 tipc_net_route_msg(obuf);
2453         }
2454         buf_discard(buf);
2455 }
2456
2457 /*
2458  *  Fragmentation/defragmentation:
2459  */
2460
2461
2462 /*
2463  * link_send_long_buf: Entry for buffers needing fragmentation.
2464  * The buffer is complete, inclusive total message length.
2465  * Returns user data length.
2466  */
2467 static int link_send_long_buf(struct tipc_link *l_ptr, struct sk_buff *buf)
2468 {
2469         struct sk_buff *buf_chain = NULL;
2470         struct sk_buff *buf_chain_tail = (struct sk_buff *)&buf_chain;
2471         struct tipc_msg *inmsg = buf_msg(buf);
2472         struct tipc_msg fragm_hdr;
2473         u32 insize = msg_size(inmsg);
2474         u32 dsz = msg_data_sz(inmsg);
2475         unchar *crs = buf->data;
2476         u32 rest = insize;
2477         u32 pack_sz = l_ptr->max_pkt;
2478         u32 fragm_sz = pack_sz - INT_H_SIZE;
2479         u32 fragm_no = 0;
2480         u32 destaddr;
2481
2482         if (msg_short(inmsg))
2483                 destaddr = l_ptr->addr;
2484         else
2485                 destaddr = msg_destnode(inmsg);
2486
2487         /* Prepare reusable fragment header: */
2488
2489         tipc_msg_init(&fragm_hdr, MSG_FRAGMENTER, FIRST_FRAGMENT,
2490                  INT_H_SIZE, destaddr);
2491
2492         /* Chop up message: */
2493
2494         while (rest > 0) {
2495                 struct sk_buff *fragm;
2496
2497                 if (rest <= fragm_sz) {
2498                         fragm_sz = rest;
2499                         msg_set_type(&fragm_hdr, LAST_FRAGMENT);
2500                 }
2501                 fragm = tipc_buf_acquire(fragm_sz + INT_H_SIZE);
2502                 if (fragm == NULL) {
2503                         buf_discard(buf);
2504                         while (buf_chain) {
2505                                 buf = buf_chain;
2506                                 buf_chain = buf_chain->next;
2507                                 buf_discard(buf);
2508                         }
2509                         return -ENOMEM;
2510                 }
2511                 msg_set_size(&fragm_hdr, fragm_sz + INT_H_SIZE);
2512                 fragm_no++;
2513                 msg_set_fragm_no(&fragm_hdr, fragm_no);
2514                 skb_copy_to_linear_data(fragm, &fragm_hdr, INT_H_SIZE);
2515                 skb_copy_to_linear_data_offset(fragm, INT_H_SIZE, crs,
2516                                                fragm_sz);
2517                 buf_chain_tail->next = fragm;
2518                 buf_chain_tail = fragm;
2519
2520                 rest -= fragm_sz;
2521                 crs += fragm_sz;
2522                 msg_set_type(&fragm_hdr, FRAGMENT);
2523         }
2524         buf_discard(buf);
2525
2526         /* Append chain of fragments to send queue & send them */
2527
2528         l_ptr->long_msg_seq_no++;
2529         link_add_chain_to_outqueue(l_ptr, buf_chain, l_ptr->long_msg_seq_no);
2530         l_ptr->stats.sent_fragments += fragm_no;
2531         l_ptr->stats.sent_fragmented++;
2532         tipc_link_push_queue(l_ptr);
2533
2534         return dsz;
2535 }
2536
2537 /*
2538  * A pending message being re-assembled must store certain values
2539  * to handle subsequent fragments correctly. The following functions
2540  * help storing these values in unused, available fields in the
2541  * pending message. This makes dynamic memory allocation unnecessary.
2542  */
2543
2544 static void set_long_msg_seqno(struct sk_buff *buf, u32 seqno)
2545 {
2546         msg_set_seqno(buf_msg(buf), seqno);
2547 }
2548
2549 static u32 get_fragm_size(struct sk_buff *buf)
2550 {
2551         return msg_ack(buf_msg(buf));
2552 }
2553
2554 static void set_fragm_size(struct sk_buff *buf, u32 sz)
2555 {
2556         msg_set_ack(buf_msg(buf), sz);
2557 }
2558
2559 static u32 get_expected_frags(struct sk_buff *buf)
2560 {
2561         return msg_bcast_ack(buf_msg(buf));
2562 }
2563
2564 static void set_expected_frags(struct sk_buff *buf, u32 exp)
2565 {
2566         msg_set_bcast_ack(buf_msg(buf), exp);
2567 }
2568
2569 static u32 get_timer_cnt(struct sk_buff *buf)
2570 {
2571         return msg_reroute_cnt(buf_msg(buf));
2572 }
2573
2574 static void incr_timer_cnt(struct sk_buff *buf)
2575 {
2576         msg_incr_reroute_cnt(buf_msg(buf));
2577 }
2578
2579 /*
2580  * tipc_link_recv_fragment(): Called with node lock on. Returns
2581  * the reassembled buffer if message is complete.
2582  */
2583 int tipc_link_recv_fragment(struct sk_buff **pending, struct sk_buff **fb,
2584                             struct tipc_msg **m)
2585 {
2586         struct sk_buff *prev = NULL;
2587         struct sk_buff *fbuf = *fb;
2588         struct tipc_msg *fragm = buf_msg(fbuf);
2589         struct sk_buff *pbuf = *pending;
2590         u32 long_msg_seq_no = msg_long_msgno(fragm);
2591
2592         *fb = NULL;
2593
2594         /* Is there an incomplete message waiting for this fragment? */
2595
2596         while (pbuf && ((buf_seqno(pbuf) != long_msg_seq_no) ||
2597                         (msg_orignode(fragm) != msg_orignode(buf_msg(pbuf))))) {
2598                 prev = pbuf;
2599                 pbuf = pbuf->next;
2600         }
2601
2602         if (!pbuf && (msg_type(fragm) == FIRST_FRAGMENT)) {
2603                 struct tipc_msg *imsg = (struct tipc_msg *)msg_data(fragm);
2604                 u32 msg_sz = msg_size(imsg);
2605                 u32 fragm_sz = msg_data_sz(fragm);
2606                 u32 exp_fragm_cnt = msg_sz/fragm_sz + !!(msg_sz % fragm_sz);
2607                 u32 max =  TIPC_MAX_USER_MSG_SIZE + NAMED_H_SIZE;
2608                 if (msg_type(imsg) == TIPC_MCAST_MSG)
2609                         max = TIPC_MAX_USER_MSG_SIZE + MCAST_H_SIZE;
2610                 if (msg_size(imsg) > max) {
2611                         buf_discard(fbuf);
2612                         return 0;
2613                 }
2614                 pbuf = tipc_buf_acquire(msg_size(imsg));
2615                 if (pbuf != NULL) {
2616                         pbuf->next = *pending;
2617                         *pending = pbuf;
2618                         skb_copy_to_linear_data(pbuf, imsg,
2619                                                 msg_data_sz(fragm));
2620                         /*  Prepare buffer for subsequent fragments. */
2621
2622                         set_long_msg_seqno(pbuf, long_msg_seq_no);
2623                         set_fragm_size(pbuf, fragm_sz);
2624                         set_expected_frags(pbuf, exp_fragm_cnt - 1);
2625                 } else {
2626                         warn("Link unable to reassemble fragmented message\n");
2627                 }
2628                 buf_discard(fbuf);
2629                 return 0;
2630         } else if (pbuf && (msg_type(fragm) != FIRST_FRAGMENT)) {
2631                 u32 dsz = msg_data_sz(fragm);
2632                 u32 fsz = get_fragm_size(pbuf);
2633                 u32 crs = ((msg_fragm_no(fragm) - 1) * fsz);
2634                 u32 exp_frags = get_expected_frags(pbuf) - 1;
2635                 skb_copy_to_linear_data_offset(pbuf, crs,
2636                                                msg_data(fragm), dsz);
2637                 buf_discard(fbuf);
2638
2639                 /* Is message complete? */
2640
2641                 if (exp_frags == 0) {
2642                         if (prev)
2643                                 prev->next = pbuf->next;
2644                         else
2645                                 *pending = pbuf->next;
2646                         msg_reset_reroute_cnt(buf_msg(pbuf));
2647                         *fb = pbuf;
2648                         *m = buf_msg(pbuf);
2649                         return 1;
2650                 }
2651                 set_expected_frags(pbuf, exp_frags);
2652                 return 0;
2653         }
2654         buf_discard(fbuf);
2655         return 0;
2656 }
2657
2658 /**
2659  * link_check_defragm_bufs - flush stale incoming message fragments
2660  * @l_ptr: pointer to link
2661  */
2662
2663 static void link_check_defragm_bufs(struct tipc_link *l_ptr)
2664 {
2665         struct sk_buff *prev = NULL;
2666         struct sk_buff *next = NULL;
2667         struct sk_buff *buf = l_ptr->defragm_buf;
2668
2669         if (!buf)
2670                 return;
2671         if (!link_working_working(l_ptr))
2672                 return;
2673         while (buf) {
2674                 u32 cnt = get_timer_cnt(buf);
2675
2676                 next = buf->next;
2677                 if (cnt < 4) {
2678                         incr_timer_cnt(buf);
2679                         prev = buf;
2680                 } else {
2681                         if (prev)
2682                                 prev->next = buf->next;
2683                         else
2684                                 l_ptr->defragm_buf = buf->next;
2685                         buf_discard(buf);
2686                 }
2687                 buf = next;
2688         }
2689 }
2690
2691
2692
2693 static void link_set_supervision_props(struct tipc_link *l_ptr, u32 tolerance)
2694 {
2695         if ((tolerance < TIPC_MIN_LINK_TOL) || (tolerance > TIPC_MAX_LINK_TOL))
2696                 return;
2697
2698         l_ptr->tolerance = tolerance;
2699         l_ptr->continuity_interval =
2700                 ((tolerance / 4) > 500) ? 500 : tolerance / 4;
2701         l_ptr->abort_limit = tolerance / (l_ptr->continuity_interval / 4);
2702 }
2703
2704
2705 void tipc_link_set_queue_limits(struct tipc_link *l_ptr, u32 window)
2706 {
2707         /* Data messages from this node, inclusive FIRST_FRAGM */
2708         l_ptr->queue_limit[TIPC_LOW_IMPORTANCE] = window;
2709         l_ptr->queue_limit[TIPC_MEDIUM_IMPORTANCE] = (window / 3) * 4;
2710         l_ptr->queue_limit[TIPC_HIGH_IMPORTANCE] = (window / 3) * 5;
2711         l_ptr->queue_limit[TIPC_CRITICAL_IMPORTANCE] = (window / 3) * 6;
2712         /* Transiting data messages,inclusive FIRST_FRAGM */
2713         l_ptr->queue_limit[TIPC_LOW_IMPORTANCE + 4] = 300;
2714         l_ptr->queue_limit[TIPC_MEDIUM_IMPORTANCE + 4] = 600;
2715         l_ptr->queue_limit[TIPC_HIGH_IMPORTANCE + 4] = 900;
2716         l_ptr->queue_limit[TIPC_CRITICAL_IMPORTANCE + 4] = 1200;
2717         l_ptr->queue_limit[CONN_MANAGER] = 1200;
2718         l_ptr->queue_limit[CHANGEOVER_PROTOCOL] = 2500;
2719         l_ptr->queue_limit[NAME_DISTRIBUTOR] = 3000;
2720         /* FRAGMENT and LAST_FRAGMENT packets */
2721         l_ptr->queue_limit[MSG_FRAGMENTER] = 4000;
2722 }
2723
2724 /**
2725  * link_find_link - locate link by name
2726  * @name - ptr to link name string
2727  * @node - ptr to area to be filled with ptr to associated node
2728  *
2729  * Caller must hold 'tipc_net_lock' to ensure node and bearer are not deleted;
2730  * this also prevents link deletion.
2731  *
2732  * Returns pointer to link (or 0 if invalid link name).
2733  */
2734
2735 static struct tipc_link *link_find_link(const char *name,
2736                                         struct tipc_node **node)
2737 {
2738         struct tipc_link_name link_name_parts;
2739         struct tipc_bearer *b_ptr;
2740         struct tipc_link *l_ptr;
2741
2742         if (!link_name_validate(name, &link_name_parts))
2743                 return NULL;
2744
2745         b_ptr = tipc_bearer_find_interface(link_name_parts.if_local);
2746         if (!b_ptr)
2747                 return NULL;
2748
2749         *node = tipc_node_find(link_name_parts.addr_peer);
2750         if (!*node)
2751                 return NULL;
2752
2753         l_ptr = (*node)->links[b_ptr->identity];
2754         if (!l_ptr || strcmp(l_ptr->name, name))
2755                 return NULL;
2756
2757         return l_ptr;
2758 }
2759
2760 /**
2761  * link_value_is_valid -- validate proposed link tolerance/priority/window
2762  *
2763  * @cmd - value type (TIPC_CMD_SET_LINK_*)
2764  * @new_value - the new value
2765  *
2766  * Returns 1 if value is within range, 0 if not.
2767  */
2768
2769 static int link_value_is_valid(u16 cmd, u32 new_value)
2770 {
2771         switch (cmd) {
2772         case TIPC_CMD_SET_LINK_TOL:
2773                 return (new_value >= TIPC_MIN_LINK_TOL) &&
2774                         (new_value <= TIPC_MAX_LINK_TOL);
2775         case TIPC_CMD_SET_LINK_PRI:
2776                 return (new_value <= TIPC_MAX_LINK_PRI);
2777         case TIPC_CMD_SET_LINK_WINDOW:
2778                 return (new_value >= TIPC_MIN_LINK_WIN) &&
2779                         (new_value <= TIPC_MAX_LINK_WIN);
2780         }
2781         return 0;
2782 }
2783
2784
2785 /**
2786  * link_cmd_set_value - change priority/tolerance/window for link/bearer/media
2787  * @name - ptr to link, bearer, or media name
2788  * @new_value - new value of link, bearer, or media setting
2789  * @cmd - which link, bearer, or media attribute to set (TIPC_CMD_SET_LINK_*)
2790  *
2791  * Caller must hold 'tipc_net_lock' to ensure link/bearer/media is not deleted.
2792  *
2793  * Returns 0 if value updated and negative value on error.
2794  */
2795
2796 static int link_cmd_set_value(const char *name, u32 new_value, u16 cmd)
2797 {
2798         struct tipc_node *node;
2799         struct tipc_link *l_ptr;
2800         struct tipc_bearer *b_ptr;
2801         struct tipc_media *m_ptr;
2802
2803         l_ptr = link_find_link(name, &node);
2804         if (l_ptr) {
2805                 /*
2806                  * acquire node lock for tipc_link_send_proto_msg().
2807                  * see "TIPC locking policy" in net.c.
2808                  */
2809                 tipc_node_lock(node);
2810                 switch (cmd) {
2811                 case TIPC_CMD_SET_LINK_TOL:
2812                         link_set_supervision_props(l_ptr, new_value);
2813                         tipc_link_send_proto_msg(l_ptr,
2814                                 STATE_MSG, 0, 0, new_value, 0, 0);
2815                         break;
2816                 case TIPC_CMD_SET_LINK_PRI:
2817                         l_ptr->priority = new_value;
2818                         tipc_link_send_proto_msg(l_ptr,
2819                                 STATE_MSG, 0, 0, 0, new_value, 0);
2820                         break;
2821                 case TIPC_CMD_SET_LINK_WINDOW:
2822                         tipc_link_set_queue_limits(l_ptr, new_value);
2823                         break;
2824                 }
2825                 tipc_node_unlock(node);
2826                 return 0;
2827         }
2828
2829         b_ptr = tipc_bearer_find(name);
2830         if (b_ptr) {
2831                 switch (cmd) {
2832                 case TIPC_CMD_SET_LINK_TOL:
2833                         b_ptr->tolerance = new_value;
2834                         return 0;
2835                 case TIPC_CMD_SET_LINK_PRI:
2836                         b_ptr->priority = new_value;
2837                         return 0;
2838                 case TIPC_CMD_SET_LINK_WINDOW:
2839                         b_ptr->window = new_value;
2840                         return 0;
2841                 }
2842                 return -EINVAL;
2843         }
2844
2845         m_ptr = tipc_media_find(name);
2846         if (!m_ptr)
2847                 return -ENODEV;
2848         switch (cmd) {
2849         case TIPC_CMD_SET_LINK_TOL:
2850                 m_ptr->tolerance = new_value;
2851                 return 0;
2852         case TIPC_CMD_SET_LINK_PRI:
2853                 m_ptr->priority = new_value;
2854                 return 0;
2855         case TIPC_CMD_SET_LINK_WINDOW:
2856                 m_ptr->window = new_value;
2857                 return 0;
2858         }
2859         return -EINVAL;
2860 }
2861
2862 struct sk_buff *tipc_link_cmd_config(const void *req_tlv_area, int req_tlv_space,
2863                                      u16 cmd)
2864 {
2865         struct tipc_link_config *args;
2866         u32 new_value;
2867         int res;
2868
2869         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_CONFIG))
2870                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2871
2872         args = (struct tipc_link_config *)TLV_DATA(req_tlv_area);
2873         new_value = ntohl(args->value);
2874
2875         if (!link_value_is_valid(cmd, new_value))
2876                 return tipc_cfg_reply_error_string(
2877                         "cannot change, value invalid");
2878
2879         if (!strcmp(args->name, tipc_bclink_name)) {
2880                 if ((cmd == TIPC_CMD_SET_LINK_WINDOW) &&
2881                     (tipc_bclink_set_queue_limits(new_value) == 0))
2882                         return tipc_cfg_reply_none();
2883                 return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
2884                                                    " (cannot change setting on broadcast link)");
2885         }
2886
2887         read_lock_bh(&tipc_net_lock);
2888         res = link_cmd_set_value(args->name, new_value, cmd);
2889         read_unlock_bh(&tipc_net_lock);
2890         if (res)
2891                 return tipc_cfg_reply_error_string("cannot change link setting");
2892
2893         return tipc_cfg_reply_none();
2894 }
2895
2896 /**
2897  * link_reset_statistics - reset link statistics
2898  * @l_ptr: pointer to link
2899  */
2900
2901 static void link_reset_statistics(struct tipc_link *l_ptr)
2902 {
2903         memset(&l_ptr->stats, 0, sizeof(l_ptr->stats));
2904         l_ptr->stats.sent_info = l_ptr->next_out_no;
2905         l_ptr->stats.recv_info = l_ptr->next_in_no;
2906 }
2907
2908 struct sk_buff *tipc_link_cmd_reset_stats(const void *req_tlv_area, int req_tlv_space)
2909 {
2910         char *link_name;
2911         struct tipc_link *l_ptr;
2912         struct tipc_node *node;
2913
2914         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_NAME))
2915                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2916
2917         link_name = (char *)TLV_DATA(req_tlv_area);
2918         if (!strcmp(link_name, tipc_bclink_name)) {
2919                 if (tipc_bclink_reset_stats())
2920                         return tipc_cfg_reply_error_string("link not found");
2921                 return tipc_cfg_reply_none();
2922         }
2923
2924         read_lock_bh(&tipc_net_lock);
2925         l_ptr = link_find_link(link_name, &node);
2926         if (!l_ptr) {
2927                 read_unlock_bh(&tipc_net_lock);
2928                 return tipc_cfg_reply_error_string("link not found");
2929         }
2930
2931         tipc_node_lock(node);
2932         link_reset_statistics(l_ptr);
2933         tipc_node_unlock(node);
2934         read_unlock_bh(&tipc_net_lock);
2935         return tipc_cfg_reply_none();
2936 }
2937
2938 /**
2939  * percent - convert count to a percentage of total (rounding up or down)
2940  */
2941
2942 static u32 percent(u32 count, u32 total)
2943 {
2944         return (count * 100 + (total / 2)) / total;
2945 }
2946
2947 /**
2948  * tipc_link_stats - print link statistics
2949  * @name: link name
2950  * @buf: print buffer area
2951  * @buf_size: size of print buffer area
2952  *
2953  * Returns length of print buffer data string (or 0 if error)
2954  */
2955
2956 static int tipc_link_stats(const char *name, char *buf, const u32 buf_size)
2957 {
2958         struct print_buf pb;
2959         struct tipc_link *l_ptr;
2960         struct tipc_node *node;
2961         char *status;
2962         u32 profile_total = 0;
2963
2964         if (!strcmp(name, tipc_bclink_name))
2965                 return tipc_bclink_stats(buf, buf_size);
2966
2967         tipc_printbuf_init(&pb, buf, buf_size);
2968
2969         read_lock_bh(&tipc_net_lock);
2970         l_ptr = link_find_link(name, &node);
2971         if (!l_ptr) {
2972                 read_unlock_bh(&tipc_net_lock);
2973                 return 0;
2974         }
2975         tipc_node_lock(node);
2976
2977         if (tipc_link_is_active(l_ptr))
2978                 status = "ACTIVE";
2979         else if (tipc_link_is_up(l_ptr))
2980                 status = "STANDBY";
2981         else
2982                 status = "DEFUNCT";
2983         tipc_printf(&pb, "Link <%s>\n"
2984                          "  %s  MTU:%u  Priority:%u  Tolerance:%u ms"
2985                          "  Window:%u packets\n",
2986                     l_ptr->name, status, l_ptr->max_pkt,
2987                     l_ptr->priority, l_ptr->tolerance, l_ptr->queue_limit[0]);
2988         tipc_printf(&pb, "  RX packets:%u fragments:%u/%u bundles:%u/%u\n",
2989                     l_ptr->next_in_no - l_ptr->stats.recv_info,
2990                     l_ptr->stats.recv_fragments,
2991                     l_ptr->stats.recv_fragmented,
2992                     l_ptr->stats.recv_bundles,
2993                     l_ptr->stats.recv_bundled);
2994         tipc_printf(&pb, "  TX packets:%u fragments:%u/%u bundles:%u/%u\n",
2995                     l_ptr->next_out_no - l_ptr->stats.sent_info,
2996                     l_ptr->stats.sent_fragments,
2997                     l_ptr->stats.sent_fragmented,
2998                     l_ptr->stats.sent_bundles,
2999                     l_ptr->stats.sent_bundled);
3000         profile_total = l_ptr->stats.msg_length_counts;
3001         if (!profile_total)
3002                 profile_total = 1;
3003         tipc_printf(&pb, "  TX profile sample:%u packets  average:%u octets\n"
3004                          "  0-64:%u%% -256:%u%% -1024:%u%% -4096:%u%% "
3005                          "-16384:%u%% -32768:%u%% -66000:%u%%\n",
3006                     l_ptr->stats.msg_length_counts,
3007                     l_ptr->stats.msg_lengths_total / profile_total,
3008                     percent(l_ptr->stats.msg_length_profile[0], profile_total),
3009                     percent(l_ptr->stats.msg_length_profile[1], profile_total),
3010                     percent(l_ptr->stats.msg_length_profile[2], profile_total),
3011                     percent(l_ptr->stats.msg_length_profile[3], profile_total),
3012                     percent(l_ptr->stats.msg_length_profile[4], profile_total),
3013                     percent(l_ptr->stats.msg_length_profile[5], profile_total),
3014                     percent(l_ptr->stats.msg_length_profile[6], profile_total));
3015         tipc_printf(&pb, "  RX states:%u probes:%u naks:%u defs:%u dups:%u\n",
3016                     l_ptr->stats.recv_states,
3017                     l_ptr->stats.recv_probes,
3018                     l_ptr->stats.recv_nacks,
3019                     l_ptr->stats.deferred_recv,
3020                     l_ptr->stats.duplicates);
3021         tipc_printf(&pb, "  TX states:%u probes:%u naks:%u acks:%u dups:%u\n",
3022                     l_ptr->stats.sent_states,
3023                     l_ptr->stats.sent_probes,
3024                     l_ptr->stats.sent_nacks,
3025                     l_ptr->stats.sent_acks,
3026                     l_ptr->stats.retransmitted);
3027         tipc_printf(&pb, "  Congestion bearer:%u link:%u  Send queue max:%u avg:%u\n",
3028                     l_ptr->stats.bearer_congs,
3029                     l_ptr->stats.link_congs,
3030                     l_ptr->stats.max_queue_sz,
3031                     l_ptr->stats.queue_sz_counts
3032                     ? (l_ptr->stats.accu_queue_sz / l_ptr->stats.queue_sz_counts)
3033                     : 0);
3034
3035         tipc_node_unlock(node);
3036         read_unlock_bh(&tipc_net_lock);
3037         return tipc_printbuf_validate(&pb);
3038 }
3039
3040 #define MAX_LINK_STATS_INFO 2000
3041
3042 struct sk_buff *tipc_link_cmd_show_stats(const void *req_tlv_area, int req_tlv_space)
3043 {
3044         struct sk_buff *buf;
3045         struct tlv_desc *rep_tlv;
3046         int str_len;
3047
3048         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_NAME))
3049                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
3050
3051         buf = tipc_cfg_reply_alloc(TLV_SPACE(MAX_LINK_STATS_INFO));
3052         if (!buf)
3053                 return NULL;
3054
3055         rep_tlv = (struct tlv_desc *)buf->data;
3056
3057         str_len = tipc_link_stats((char *)TLV_DATA(req_tlv_area),
3058                                   (char *)TLV_DATA(rep_tlv), MAX_LINK_STATS_INFO);
3059         if (!str_len) {
3060                 buf_discard(buf);
3061                 return tipc_cfg_reply_error_string("link not found");
3062         }
3063
3064         skb_put(buf, TLV_SPACE(str_len));
3065         TLV_SET(rep_tlv, TIPC_TLV_ULTRA_STRING, NULL, str_len);
3066
3067         return buf;
3068 }
3069
3070 /**
3071  * tipc_link_get_max_pkt - get maximum packet size to use when sending to destination
3072  * @dest: network address of destination node
3073  * @selector: used to select from set of active links
3074  *
3075  * If no active link can be found, uses default maximum packet size.
3076  */
3077
3078 u32 tipc_link_get_max_pkt(u32 dest, u32 selector)
3079 {
3080         struct tipc_node *n_ptr;
3081         struct tipc_link *l_ptr;
3082         u32 res = MAX_PKT_DEFAULT;
3083
3084         if (dest == tipc_own_addr)
3085                 return MAX_MSG_SIZE;
3086
3087         read_lock_bh(&tipc_net_lock);
3088         n_ptr = tipc_node_find(dest);
3089         if (n_ptr) {
3090                 tipc_node_lock(n_ptr);
3091                 l_ptr = n_ptr->active_links[selector & 1];
3092                 if (l_ptr)
3093                         res = l_ptr->max_pkt;
3094                 tipc_node_unlock(n_ptr);
3095         }
3096         read_unlock_bh(&tipc_net_lock);
3097         return res;
3098 }
3099
3100 static void link_print(struct tipc_link *l_ptr, const char *str)
3101 {
3102         char print_area[256];
3103         struct print_buf pb;
3104         struct print_buf *buf = &pb;
3105
3106         tipc_printbuf_init(buf, print_area, sizeof(print_area));
3107
3108         tipc_printf(buf, str);
3109         tipc_printf(buf, "Link %x<%s>:",
3110                     l_ptr->addr, l_ptr->b_ptr->name);
3111
3112 #ifdef CONFIG_TIPC_DEBUG
3113         if (link_reset_reset(l_ptr) || link_reset_unknown(l_ptr))
3114                 goto print_state;
3115
3116         tipc_printf(buf, ": NXO(%u):", mod(l_ptr->next_out_no));
3117         tipc_printf(buf, "NXI(%u):", mod(l_ptr->next_in_no));
3118         tipc_printf(buf, "SQUE");
3119         if (l_ptr->first_out) {
3120                 tipc_printf(buf, "[%u..", buf_seqno(l_ptr->first_out));
3121                 if (l_ptr->next_out)
3122                         tipc_printf(buf, "%u..", buf_seqno(l_ptr->next_out));
3123                 tipc_printf(buf, "%u]", buf_seqno(l_ptr->last_out));
3124                 if ((mod(buf_seqno(l_ptr->last_out) -
3125                          buf_seqno(l_ptr->first_out))
3126                      != (l_ptr->out_queue_size - 1)) ||
3127                     (l_ptr->last_out->next != NULL)) {
3128                         tipc_printf(buf, "\nSend queue inconsistency\n");
3129                         tipc_printf(buf, "first_out= %p ", l_ptr->first_out);
3130                         tipc_printf(buf, "next_out= %p ", l_ptr->next_out);
3131                         tipc_printf(buf, "last_out= %p ", l_ptr->last_out);
3132                 }
3133         } else
3134                 tipc_printf(buf, "[]");
3135         tipc_printf(buf, "SQSIZ(%u)", l_ptr->out_queue_size);
3136         if (l_ptr->oldest_deferred_in) {
3137                 u32 o = buf_seqno(l_ptr->oldest_deferred_in);
3138                 u32 n = buf_seqno(l_ptr->newest_deferred_in);
3139                 tipc_printf(buf, ":RQUE[%u..%u]", o, n);
3140                 if (l_ptr->deferred_inqueue_sz != mod((n + 1) - o)) {
3141                         tipc_printf(buf, ":RQSIZ(%u)",
3142                                     l_ptr->deferred_inqueue_sz);
3143                 }
3144         }
3145 print_state:
3146 #endif
3147
3148         if (link_working_unknown(l_ptr))
3149                 tipc_printf(buf, ":WU");
3150         else if (link_reset_reset(l_ptr))
3151                 tipc_printf(buf, ":RR");
3152         else if (link_reset_unknown(l_ptr))
3153                 tipc_printf(buf, ":RU");
3154         else if (link_working_working(l_ptr))
3155                 tipc_printf(buf, ":WW");
3156         tipc_printf(buf, "\n");
3157
3158         tipc_printbuf_validate(buf);
3159         info("%s", print_area);
3160 }
3161