net/tipc/bcast.c

   1 /*
   2  * net/tipc/bcast.c: TIPC broadcast code
   3  *
   4  * Copyright (c) 2004-2006, Ericsson AB
   5  * Copyright (c) 2004, Intel Corporation.
   6  * Copyright (c) 2005, Wind River Systems
   7  * All rights reserved.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions are met:
  11  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  * 3. Neither the names of the copyright holders nor the names of its
  18  *    contributors may be used to endorse or promote products derived from
  19  *    this software without specific prior written permission.
  20  *
  21  * Alternatively, this software may be distributed under the terms of the
  22  * GNU General Public License ("GPL") version 2 as published by the Free
  23  * Software Foundation.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  26  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  27  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  28  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  29  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  30  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  31  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  32  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  33  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  34  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  35  * POSSIBILITY OF SUCH DAMAGE.
  36  */
  37
  38 #include "core.h"
  39 #include "msg.h"
  40 #include "dbg.h"
  41 #include "link.h"
  42 #include "net.h"
  43 #include "node.h"
  44 #include "port.h"
  45 #include "addr.h"
  46 #include "node_subscr.h"
  47 #include "name_distr.h"
  48 #include "bearer.h"
  49 #include "name_table.h"
  50 #include "bcast.h"
  51
  52
  53 #define MAX_PKT_DEFAULT_MCAST 1500      /* bcast link max packet size (fixed) */
  54
  55 #define BCLINK_WIN_DEFAULT 20           /* bcast link window size (default) */
  56
  57 #define BCLINK_LOG_BUF_SIZE 0
  58
  59 /**
  60  * struct bcbearer_pair - a pair of bearers used by broadcast link
  61  * @primary: pointer to primary bearer
  62  * @secondary: pointer to secondary bearer
  63  *
  64  * Bearers must have same priority and same set of reachable destinations
  65  * to be paired.
  66  */
  67
  68 struct bcbearer_pair {
  69         struct bearer *primary;
  70         struct bearer *secondary;
  71 };
  72
  73 /**
  74  * struct bcbearer - bearer used by broadcast link
  75  * @bearer: (non-standard) broadcast bearer structure
  76  * @media: (non-standard) broadcast media structure
  77  * @bpairs: array of bearer pairs
  78  * @bpairs_temp: array of bearer pairs used during creation of "bpairs"
  79  */
  80
  81 struct bcbearer {
  82         struct bearer bearer;
  83         struct media media;
  84         struct bcbearer_pair bpairs[MAX_BEARERS];
  85         struct bcbearer_pair bpairs_temp[TIPC_MAX_LINK_PRI + 1];
  86 };
  87
  88 /**
  89  * struct bclink - link used for broadcast messages
  90  * @link: (non-standard) broadcast link structure
  91  * @node: (non-standard) node structure representing b'cast link's peer node
  92  *
  93  * Handles sequence numbering, fragmentation, bundling, etc.
  94  */
  95
  96 struct bclink {
  97         struct link link;
  98         struct node node;
  99 };
 100
 101
 102 static struct bcbearer *bcbearer = NULL;
 103 static struct bclink *bclink = NULL;
 104 static struct link *bcl = NULL;
 105 static spinlock_t bc_lock = SPIN_LOCK_UNLOCKED;
 106
 107 char tipc_bclink_name[] = "multicast-link";
 108
 109
 110 static inline u32 buf_seqno(struct sk_buff *buf)
 111 {
 112         return msg_seqno(buf_msg(buf));
 113 }
 114
 115 static inline u32 bcbuf_acks(struct sk_buff *buf)
 116 {
 117         return (u32)(unsigned long)TIPC_SKB_CB(buf)->handle;
 118 }
 119
 120 static inline void bcbuf_set_acks(struct sk_buff *buf, u32 acks)
 121 {
 122         TIPC_SKB_CB(buf)->handle = (void *)(unsigned long)acks;
 123 }
 124
 125 static inline void bcbuf_decr_acks(struct sk_buff *buf)
 126 {
 127         bcbuf_set_acks(buf, bcbuf_acks(buf) - 1);
 128 }
 129
 130
 131 /**
 132  * bclink_set_gap - set gap according to contents of current deferred pkt queue
 133  *
 134  * Called with 'node' locked, bc_lock unlocked
 135  */
 136
 137 static inline void bclink_set_gap(struct node *n_ptr)
 138 {
 139         struct sk_buff *buf = n_ptr->bclink.deferred_head;
 140
 141         n_ptr->bclink.gap_after = n_ptr->bclink.gap_to =
 142                 mod(n_ptr->bclink.last_in);
 143         if (unlikely(buf != NULL))
 144                 n_ptr->bclink.gap_to = mod(buf_seqno(buf) - 1);
 145 }
 146
 147 /**
 148  * bclink_ack_allowed - test if ACK or NACK message can be sent at this moment
 149  *
 150  * This mechanism endeavours to prevent all nodes in network from trying
 151  * to ACK or NACK at the same time.
 152  *
 153  * Note: TIPC uses a different trigger to distribute ACKs than it does to
 154  *       distribute NACKs, but tries to use the same spacing (divide by 16).
 155  */
 156
 157 static inline int bclink_ack_allowed(u32 n)
 158 {
 159         return((n % TIPC_MIN_LINK_WIN) == tipc_own_tag);
 160 }
 161
 162
 163 /**
 164  * bclink_retransmit_pkt - retransmit broadcast packets
 165  * @after: sequence number of last packet to *not* retransmit
 166  * @to: sequence number of last packet to retransmit
 167  *
 168  * Called with 'node' locked, bc_lock unlocked
 169  */
 170
 171 static void bclink_retransmit_pkt(u32 after, u32 to)
 172 {
 173         struct sk_buff *buf;
 174
 175         spin_lock_bh(&bc_lock);
 176         buf = bcl->first_out;
 177         while (buf && less_eq(buf_seqno(buf), after)) {
 178                 buf = buf->next;
 179         }
 180         if (buf != NULL)
 181                 tipc_link_retransmit(bcl, buf, mod(to - after));
 182         spin_unlock_bh(&bc_lock);
 183 }
 184
 185 /**
 186  * tipc_bclink_acknowledge - handle acknowledgement of broadcast packets
 187  * @n_ptr: node that sent acknowledgement info
 188  * @acked: broadcast sequence # that has been acknowledged
 189  *
 190  * Node is locked, bc_lock unlocked.
 191  */
 192
 193 void tipc_bclink_acknowledge(struct node *n_ptr, u32 acked)
 194 {
 195         struct sk_buff *crs;
 196         struct sk_buff *next;
 197         unsigned int released = 0;
 198
 199         if (less_eq(acked, n_ptr->bclink.acked))
 200                 return;
 201
 202         spin_lock_bh(&bc_lock);
 203
 204         /* Skip over packets that node has previously acknowledged */
 205
 206         crs = bcl->first_out;
 207         while (crs && less_eq(buf_seqno(crs), n_ptr->bclink.acked)) {
 208                 crs = crs->next;
 209         }
 210
 211         /* Update packets that node is now acknowledging */
 212
 213         while (crs && less_eq(buf_seqno(crs), acked)) {
 214                 next = crs->next;
 215                 bcbuf_decr_acks(crs);
 216                 if (bcbuf_acks(crs) == 0) {
 217                         bcl->first_out = next;
 218                         bcl->out_queue_size--;
 219                         buf_discard(crs);
 220                         released = 1;
 221                 }
 222                 crs = next;
 223         }
 224         n_ptr->bclink.acked = acked;
 225
 226         /* Try resolving broadcast link congestion, if necessary */
 227
 228         if (unlikely(bcl->next_out))
 229                 tipc_link_push_queue(bcl);
 230         if (unlikely(released && !list_empty(&bcl->waiting_ports)))
 231                 tipc_link_wakeup_ports(bcl, 0);
 232         spin_unlock_bh(&bc_lock);
 233 }
 234
 235 /**
 236  * bclink_send_ack - unicast an ACK msg
 237  *
 238  * tipc_net_lock and node lock set
 239  */
 240
 241 static void bclink_send_ack(struct node *n_ptr)
 242 {
 243         struct link *l_ptr = n_ptr->active_links[n_ptr->addr & 1];
 244
 245         if (l_ptr != NULL)
 246                 tipc_link_send_proto_msg(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
 247 }
 248
 249 /**
 250  * bclink_send_nack- broadcast a NACK msg
 251  *
 252  * tipc_net_lock and node lock set
 253  */
 254
 255 static void bclink_send_nack(struct node *n_ptr)
 256 {
 257         struct sk_buff *buf;
 258         struct tipc_msg *msg;
 259
 260         if (!less(n_ptr->bclink.gap_after, n_ptr->bclink.gap_to))
 261                 return;
 262
 263         buf = buf_acquire(INT_H_SIZE);
 264         if (buf) {
 265                 msg = buf_msg(buf);
 266                 msg_init(msg, BCAST_PROTOCOL, STATE_MSG,
 267                          TIPC_OK, INT_H_SIZE, n_ptr->addr);
 268                 msg_set_mc_netid(msg, tipc_net_id);
 269                 msg_set_bcast_ack(msg, mod(n_ptr->bclink.last_in));
 270                 msg_set_bcgap_after(msg, n_ptr->bclink.gap_after);
 271                 msg_set_bcgap_to(msg, n_ptr->bclink.gap_to);
 272                 msg_set_bcast_tag(msg, tipc_own_tag);
 273
 274                 if (tipc_bearer_send(&bcbearer->bearer, buf, 0)) {
 275                         bcl->stats.sent_nacks++;
 276                         buf_discard(buf);
 277                 } else {
 278                         tipc_bearer_schedule(bcl->b_ptr, bcl);
 279                         bcl->proto_msg_queue = buf;
 280                         bcl->stats.bearer_congs++;
 281                 }
 282
 283                 /*
 284                  * Ensure we doesn't send another NACK msg to the node
 285                  * until 16 more deferred messages arrive from it
 286                  * (i.e. helps prevent all nodes from NACK'ing at same time)
 287                  */
 288
 289                 n_ptr->bclink.nack_sync = tipc_own_tag;
 290         }
 291 }
 292
 293 /**
 294  * tipc_bclink_check_gap - send a NACK if a sequence gap exists
 295  *
 296  * tipc_net_lock and node lock set
 297  */
 298
 299 void tipc_bclink_check_gap(struct node *n_ptr, u32 last_sent)
 300 {
 301         if (!n_ptr->bclink.supported ||
 302             less_eq(last_sent, mod(n_ptr->bclink.last_in)))
 303                 return;
 304
 305         bclink_set_gap(n_ptr);
 306         if (n_ptr->bclink.gap_after == n_ptr->bclink.gap_to)
 307                 n_ptr->bclink.gap_to = last_sent;
 308         bclink_send_nack(n_ptr);
 309 }
 310
 311 /**
 312  * tipc_bclink_peek_nack - process a NACK msg meant for another node
 313  *
 314  * Only tipc_net_lock set.
 315  */
 316
 317 void tipc_bclink_peek_nack(u32 dest, u32 sender_tag, u32 gap_after, u32 gap_to)
 318 {
 319         struct node *n_ptr = tipc_node_find(dest);
 320         u32 my_after, my_to;
 321
 322         if (unlikely(!n_ptr || !tipc_node_is_up(n_ptr)))
 323                 return;
 324         tipc_node_lock(n_ptr);
 325         /*
 326          * Modify gap to suppress unnecessary NACKs from this node
 327          */
 328         my_after = n_ptr->bclink.gap_after;
 329         my_to = n_ptr->bclink.gap_to;
 330
 331         if (less_eq(gap_after, my_after)) {
 332                 if (less(my_after, gap_to) && less(gap_to, my_to))
 333                         n_ptr->bclink.gap_after = gap_to;
 334                 else if (less_eq(my_to, gap_to))
 335                         n_ptr->bclink.gap_to = n_ptr->bclink.gap_after;
 336         } else if (less_eq(gap_after, my_to)) {
 337                 if (less_eq(my_to, gap_to))
 338                         n_ptr->bclink.gap_to = gap_after;
 339         } else {
 340                 /*
 341                  * Expand gap if missing bufs not in deferred queue:
 342                  */
 343                 struct sk_buff *buf = n_ptr->bclink.deferred_head;
 344                 u32 prev = n_ptr->bclink.gap_to;
 345
 346                 for (; buf; buf = buf->next) {
 347                         u32 seqno = buf_seqno(buf);
 348
 349                         if (mod(seqno - prev) != 1)
 350                                 buf = NULL;
 351                         if (seqno == gap_after)
 352                                 break;
 353                         prev = seqno;
 354                 }
 355                 if (buf == NULL)
 356                         n_ptr->bclink.gap_to = gap_after;
 357         }
 358         /*
 359          * Some nodes may send a complementary NACK now:
 360          */
 361         if (bclink_ack_allowed(sender_tag + 1)) {
 362                 if (n_ptr->bclink.gap_to != n_ptr->bclink.gap_after) {
 363                         bclink_send_nack(n_ptr);
 364                         bclink_set_gap(n_ptr);
 365                 }
 366         }
 367         tipc_node_unlock(n_ptr);
 368 }
 369
 370 /**
 371  * tipc_bclink_send_msg - broadcast a packet to all nodes in cluster
 372  */
 373
 374 int tipc_bclink_send_msg(struct sk_buff *buf)
 375 {
 376         int res;
 377
 378         spin_lock_bh(&bc_lock);
 379
 380         res = tipc_link_send_buf(bcl, buf);
 381         if (unlikely(res == -ELINKCONG))
 382                 buf_discard(buf);
 383         else
 384                 bcl->stats.sent_info++;
 385
 386         if (bcl->out_queue_size > bcl->stats.max_queue_sz)
 387                 bcl->stats.max_queue_sz = bcl->out_queue_size;
 388         bcl->stats.queue_sz_counts++;
 389         bcl->stats.accu_queue_sz += bcl->out_queue_size;
 390
 391         spin_unlock_bh(&bc_lock);
 392         return res;
 393 }
 394
 395 /**
 396  * tipc_bclink_recv_pkt - receive a broadcast packet, and deliver upwards
 397  *
 398  * tipc_net_lock is read_locked, no other locks set
 399  */
 400
 401 void tipc_bclink_recv_pkt(struct sk_buff *buf)
 402 {
 403         struct tipc_msg *msg = buf_msg(buf);
 404         struct node* node = tipc_node_find(msg_prevnode(msg));
 405         u32 next_in;
 406         u32 seqno;
 407         struct sk_buff *deferred;
 408
 409         msg_dbg(msg, "<BC<<<");
 410
 411         if (unlikely(!node || !tipc_node_is_up(node) || !node->bclink.supported ||
 412                      (msg_mc_netid(msg) != tipc_net_id))) {
 413                 buf_discard(buf);
 414                 return;
 415         }
 416
 417         if (unlikely(msg_user(msg) == BCAST_PROTOCOL)) {
 418                 msg_dbg(msg, "<BCNACK<<<");
 419                 if (msg_destnode(msg) == tipc_own_addr) {
 420                         tipc_node_lock(node);
 421                         tipc_bclink_acknowledge(node, msg_bcast_ack(msg));
 422                         tipc_node_unlock(node);
 423                         bcl->stats.recv_nacks++;
 424                         bclink_retransmit_pkt(msg_bcgap_after(msg),
 425                                               msg_bcgap_to(msg));
 426                 } else {
 427                         tipc_bclink_peek_nack(msg_destnode(msg),
 428                                          msg_bcast_tag(msg),
 429                                          msg_bcgap_after(msg),
 430                                          msg_bcgap_to(msg));
 431                 }
 432                 buf_discard(buf);
 433                 return;
 434         }
 435
 436         tipc_node_lock(node);
 437 receive:
 438         deferred = node->bclink.deferred_head;
 439         next_in = mod(node->bclink.last_in + 1);
 440         seqno = msg_seqno(msg);
 441
 442         if (likely(seqno == next_in)) {
 443                 bcl->stats.recv_info++;
 444                 node->bclink.last_in++;
 445                 bclink_set_gap(node);
 446                 if (unlikely(bclink_ack_allowed(seqno))) {
 447                         bclink_send_ack(node);
 448                         bcl->stats.sent_acks++;
 449                 }
 450                 if (likely(msg_isdata(msg))) {
 451                         tipc_node_unlock(node);
 452                         tipc_port_recv_mcast(buf, NULL);
 453                 } else if (msg_user(msg) == MSG_BUNDLER) {
 454                         bcl->stats.recv_bundles++;
 455                         bcl->stats.recv_bundled += msg_msgcnt(msg);
 456                         tipc_node_unlock(node);
 457                         tipc_link_recv_bundle(buf);
 458                 } else if (msg_user(msg) == MSG_FRAGMENTER) {
 459                         bcl->stats.recv_fragments++;
 460                         if (tipc_link_recv_fragment(&node->bclink.defragm,
 461                                                     &buf, &msg))
 462                                 bcl->stats.recv_fragmented++;
 463                         tipc_node_unlock(node);
 464                         tipc_net_route_msg(buf);
 465                 } else {
 466                         tipc_node_unlock(node);
 467                         tipc_net_route_msg(buf);
 468                 }
 469                 if (deferred && (buf_seqno(deferred) == mod(next_in + 1))) {
 470                         tipc_node_lock(node);
 471                         buf = deferred;
 472                         msg = buf_msg(buf);
 473                         node->bclink.deferred_head = deferred->next;
 474                         goto receive;
 475                 }
 476                 return;
 477         } else if (less(next_in, seqno)) {
 478                 u32 gap_after = node->bclink.gap_after;
 479                 u32 gap_to = node->bclink.gap_to;
 480
 481                 if (tipc_link_defer_pkt(&node->bclink.deferred_head,
 482                                         &node->bclink.deferred_tail,
 483                                         buf)) {
 484                         node->bclink.nack_sync++;
 485                         bcl->stats.deferred_recv++;
 486                         if (seqno == mod(gap_after + 1))
 487                                 node->bclink.gap_after = seqno;
 488                         else if (less(gap_after, seqno) && less(seqno, gap_to))
 489                                 node->bclink.gap_to = seqno;
 490                 }
 491                 if (bclink_ack_allowed(node->bclink.nack_sync)) {
 492                         if (gap_to != gap_after)
 493                                 bclink_send_nack(node);
 494                         bclink_set_gap(node);
 495                 }
 496         } else {
 497                 bcl->stats.duplicates++;
 498                 buf_discard(buf);
 499         }
 500         tipc_node_unlock(node);
 501 }
 502
 503 u32 tipc_bclink_get_last_sent(void)
 504 {
 505         u32 last_sent = mod(bcl->next_out_no - 1);
 506
 507         if (bcl->next_out)
 508                 last_sent = mod(buf_seqno(bcl->next_out) - 1);
 509         return last_sent;
 510 }
 511
 512 u32 tipc_bclink_acks_missing(struct node *n_ptr)
 513 {
 514         return (n_ptr->bclink.supported &&
 515                 (tipc_bclink_get_last_sent() != n_ptr->bclink.acked));
 516 }
 517
 518
 519 /**
 520  * tipc_bcbearer_send - send a packet through the broadcast pseudo-bearer
 521  *
 522  * Send through as many bearers as necessary to reach all nodes
 523  * that support TIPC multicasting.
 524  *
 525  * Returns 0 if packet sent successfully, non-zero if not
 526  */
 527
 528 int tipc_bcbearer_send(struct sk_buff *buf,
 529                        struct tipc_bearer *unused1,
 530                        struct tipc_media_addr *unused2)
 531 {
 532         static int send_count = 0;
 533
 534         struct node_map remains;
 535         struct node_map remains_new;
 536         int bp_index;
 537         int swap_time;
 538
 539         /* Prepare buffer for broadcasting (if first time trying to send it) */
 540
 541         if (likely(!msg_non_seq(buf_msg(buf)))) {
 542                 struct tipc_msg *msg;
 543
 544                 assert(tipc_cltr_bcast_nodes.count != 0);
 545                 bcbuf_set_acks(buf, tipc_cltr_bcast_nodes.count);
 546                 msg = buf_msg(buf);
 547                 msg_set_non_seq(msg);
 548                 msg_set_mc_netid(msg, tipc_net_id);
 549         }
 550
 551         /* Determine if bearer pairs should be swapped following this attempt */
 552
 553         if ((swap_time = (++send_count >= 10)))
 554                 send_count = 0;
 555
 556         /* Send buffer over bearers until all targets reached */
 557
 558         remains = tipc_cltr_bcast_nodes;
 559
 560         for (bp_index = 0; bp_index < MAX_BEARERS; bp_index++) {
 561                 struct bearer *p = bcbearer->bpairs[bp_index].primary;
 562                 struct bearer *s = bcbearer->bpairs[bp_index].secondary;
 563
 564                 if (!p)
 565                         break;  /* no more bearers to try */
 566
 567                 tipc_nmap_diff(&remains, &p->nodes, &remains_new);
 568                 if (remains_new.count == remains.count)
 569                         continue;       /* bearer pair doesn't add anything */
 570
 571                 if (!p->publ.blocked &&
 572                     !p->media->send_msg(buf, &p->publ, &p->media->bcast_addr)) {
 573                         if (swap_time && s && !s->publ.blocked)
 574                                 goto swap;
 575                         else
 576                                 goto update;
 577                 }
 578
 579                 if (!s || s->publ.blocked ||
 580                     s->media->send_msg(buf, &s->publ, &s->media->bcast_addr))
 581                         continue;       /* unable to send using bearer pair */
 582 swap:
 583                 bcbearer->bpairs[bp_index].primary = s;
 584                 bcbearer->bpairs[bp_index].secondary = p;
 585 update:
 586                 if (remains_new.count == 0)
 587                         return TIPC_OK;
 588
 589                 remains = remains_new;
 590         }
 591
 592         /* Unable to reach all targets */
 593
 594         bcbearer->bearer.publ.blocked = 1;
 595         bcl->stats.bearer_congs++;
 596         return ~TIPC_OK;
 597 }
 598
 599 /**
 600  * tipc_bcbearer_sort - create sets of bearer pairs used by broadcast bearer
 601  */
 602
 603 void tipc_bcbearer_sort(void)
 604 {
 605         struct bcbearer_pair *bp_temp = bcbearer->bpairs_temp;
 606         struct bcbearer_pair *bp_curr;
 607         int b_index;
 608         int pri;
 609
 610         spin_lock_bh(&bc_lock);
 611
 612         /* Group bearers by priority (can assume max of two per priority) */
 613
 614         memset(bp_temp, 0, sizeof(bcbearer->bpairs_temp));
 615
 616         for (b_index = 0; b_index < MAX_BEARERS; b_index++) {
 617                 struct bearer *b = &tipc_bearers[b_index];
 618
 619                 if (!b->active || !b->nodes.count)
 620                         continue;
 621
 622                 if (!bp_temp[b->priority].primary)
 623                         bp_temp[b->priority].primary = b;
 624                 else
 625                         bp_temp[b->priority].secondary = b;
 626         }
 627
 628         /* Create array of bearer pairs for broadcasting */
 629
 630         bp_curr = bcbearer->bpairs;
 631         memset(bcbearer->bpairs, 0, sizeof(bcbearer->bpairs));
 632
 633         for (pri = TIPC_MAX_LINK_PRI; pri >= 0; pri--) {
 634
 635                 if (!bp_temp[pri].primary)
 636                         continue;
 637
 638                 bp_curr->primary = bp_temp[pri].primary;
 639
 640                 if (bp_temp[pri].secondary) {
 641                         if (tipc_nmap_equal(&bp_temp[pri].primary->nodes,
 642                                             &bp_temp[pri].secondary->nodes)) {
 643                                 bp_curr->secondary = bp_temp[pri].secondary;
 644                         } else {
 645                                 bp_curr++;
 646                                 bp_curr->primary = bp_temp[pri].secondary;
 647                         }
 648                 }
 649
 650                 bp_curr++;
 651         }
 652
 653         spin_unlock_bh(&bc_lock);
 654 }
 655
 656 /**
 657  * tipc_bcbearer_push - resolve bearer congestion
 658  *
 659  * Forces bclink to push out any unsent packets, until all packets are gone
 660  * or congestion reoccurs.
 661  * No locks set when function called
 662  */
 663
 664 void tipc_bcbearer_push(void)
 665 {
 666         struct bearer *b_ptr;
 667
 668         spin_lock_bh(&bc_lock);
 669         b_ptr = &bcbearer->bearer;
 670         if (b_ptr->publ.blocked) {
 671                 b_ptr->publ.blocked = 0;
 672                 tipc_bearer_lock_push(b_ptr);
 673         }
 674         spin_unlock_bh(&bc_lock);
 675 }
 676
 677
 678 int tipc_bclink_stats(char *buf, const u32 buf_size)
 679 {
 680         struct print_buf pb;
 681
 682         if (!bcl)
 683                 return 0;
 684
 685         tipc_printbuf_init(&pb, buf, buf_size);
 686
 687         spin_lock_bh(&bc_lock);
 688
 689         tipc_printf(&pb, "Link <%s>\n"
 690                          "  Window:%u packets\n",
 691                     bcl->name, bcl->queue_limit[0]);
 692         tipc_printf(&pb, "  RX packets:%u fragments:%u/%u bundles:%u/%u\n",
 693                     bcl->stats.recv_info,
 694                     bcl->stats.recv_fragments,
 695                     bcl->stats.recv_fragmented,
 696                     bcl->stats.recv_bundles,
 697                     bcl->stats.recv_bundled);
 698         tipc_printf(&pb, "  TX packets:%u fragments:%u/%u bundles:%u/%u\n",
 699                     bcl->stats.sent_info,
 700                     bcl->stats.sent_fragments,
 701                     bcl->stats.sent_fragmented,
 702                     bcl->stats.sent_bundles,
 703                     bcl->stats.sent_bundled);
 704         tipc_printf(&pb, "  RX naks:%u defs:%u dups:%u\n",
 705                     bcl->stats.recv_nacks,
 706                     bcl->stats.deferred_recv,
 707                     bcl->stats.duplicates);
 708         tipc_printf(&pb, "  TX naks:%u acks:%u dups:%u\n",
 709                     bcl->stats.sent_nacks,
 710                     bcl->stats.sent_acks,
 711                     bcl->stats.retransmitted);
 712         tipc_printf(&pb, "  Congestion bearer:%u link:%u  Send queue max:%u avg:%u\n",
 713                     bcl->stats.bearer_congs,
 714                     bcl->stats.link_congs,
 715                     bcl->stats.max_queue_sz,
 716                     bcl->stats.queue_sz_counts
 717                     ? (bcl->stats.accu_queue_sz / bcl->stats.queue_sz_counts)
 718                     : 0);
 719
 720         spin_unlock_bh(&bc_lock);
 721         return tipc_printbuf_validate(&pb);
 722 }
 723
 724 int tipc_bclink_reset_stats(void)
 725 {
 726         if (!bcl)
 727                 return -ENOPROTOOPT;
 728
 729         spin_lock_bh(&bc_lock);
 730         memset(&bcl->stats, 0, sizeof(bcl->stats));
 731         spin_unlock_bh(&bc_lock);
 732         return TIPC_OK;
 733 }
 734
 735 int tipc_bclink_set_queue_limits(u32 limit)
 736 {
 737         if (!bcl)
 738                 return -ENOPROTOOPT;
 739         if ((limit < TIPC_MIN_LINK_WIN) || (limit > TIPC_MAX_LINK_WIN))
 740                 return -EINVAL;
 741
 742         spin_lock_bh(&bc_lock);
 743         tipc_link_set_queue_limits(bcl, limit);
 744         spin_unlock_bh(&bc_lock);
 745         return TIPC_OK;
 746 }
 747
 748 int tipc_bclink_init(void)
 749 {
 750         bcbearer = kmalloc(sizeof(*bcbearer), GFP_ATOMIC);
 751         bclink = kmalloc(sizeof(*bclink), GFP_ATOMIC);
 752         if (!bcbearer || !bclink) {
 753  nomem:
 754                 warn("Memory squeeze; Failed to create multicast link\n");
 755                 kfree(bcbearer);
 756                 bcbearer = NULL;
 757                 kfree(bclink);
 758                 bclink = NULL;
 759                 return -ENOMEM;
 760         }
 761
 762         memset(bcbearer, 0, sizeof(struct bcbearer));
 763         INIT_LIST_HEAD(&bcbearer->bearer.cong_links);
 764         bcbearer->bearer.media = &bcbearer->media;
 765         bcbearer->media.send_msg = tipc_bcbearer_send;
 766         sprintf(bcbearer->media.name, "tipc-multicast");
 767
 768         bcl = &bclink->link;
 769         memset(bclink, 0, sizeof(struct bclink));
 770         INIT_LIST_HEAD(&bcl->waiting_ports);
 771         bcl->next_out_no = 1;
 772         bclink->node.lock =  SPIN_LOCK_UNLOCKED;
 773         bcl->owner = &bclink->node;
 774         bcl->max_pkt = MAX_PKT_DEFAULT_MCAST;
 775         tipc_link_set_queue_limits(bcl, BCLINK_WIN_DEFAULT);
 776         bcl->b_ptr = &bcbearer->bearer;
 777         bcl->state = WORKING_WORKING;
 778         sprintf(bcl->name, tipc_bclink_name);
 779
 780         if (BCLINK_LOG_BUF_SIZE) {
 781                 char *pb = kmalloc(BCLINK_LOG_BUF_SIZE, GFP_ATOMIC);
 782
 783                 if (!pb)
 784                         goto nomem;
 785                 tipc_printbuf_init(&bcl->print_buf, pb, BCLINK_LOG_BUF_SIZE);
 786         }
 787
 788         return TIPC_OK;
 789 }
 790
 791 void tipc_bclink_stop(void)
 792 {
 793         spin_lock_bh(&bc_lock);
 794         if (bcbearer) {
 795                 tipc_link_stop(bcl);
 796                 if (BCLINK_LOG_BUF_SIZE)
 797                         kfree(bcl->print_buf.buf);
 798                 bcl = NULL;
 799                 kfree(bclink);
 800                 bclink = NULL;
 801                 kfree(bcbearer);
 802                 bcbearer = NULL;
 803         }
 804         spin_unlock_bh(&bc_lock);
 805 }
 806