xref: /linux/net/tipc/bcast.c (revision b43ab901d671e3e3cad425ea5e9a3c74e266dcdd)
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, 2010-2011, 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 "link.h"
40 #include "port.h"
41 #include "bcast.h"
42 #include "name_distr.h"
43 
44 #define MAX_PKT_DEFAULT_MCAST 1500	/* bcast link max packet size (fixed) */
45 
46 #define BCLINK_WIN_DEFAULT 20		/* bcast link window size (default) */
47 
48 /**
49  * struct tipc_bcbearer_pair - a pair of bearers used by broadcast link
50  * @primary: pointer to primary bearer
51  * @secondary: pointer to secondary bearer
52  *
53  * Bearers must have same priority and same set of reachable destinations
54  * to be paired.
55  */
56 
57 struct tipc_bcbearer_pair {
58 	struct tipc_bearer *primary;
59 	struct tipc_bearer *secondary;
60 };
61 
62 /**
63  * struct tipc_bcbearer - bearer used by broadcast link
64  * @bearer: (non-standard) broadcast bearer structure
65  * @media: (non-standard) broadcast media structure
66  * @bpairs: array of bearer pairs
67  * @bpairs_temp: temporary array of bearer pairs used by tipc_bcbearer_sort()
68  * @remains: temporary node map used by tipc_bcbearer_send()
69  * @remains_new: temporary node map used tipc_bcbearer_send()
70  *
71  * Note: The fields labelled "temporary" are incorporated into the bearer
72  * to avoid consuming potentially limited stack space through the use of
73  * large local variables within multicast routines.  Concurrent access is
74  * prevented through use of the spinlock "bc_lock".
75  */
76 
77 struct tipc_bcbearer {
78 	struct tipc_bearer bearer;
79 	struct tipc_media media;
80 	struct tipc_bcbearer_pair bpairs[MAX_BEARERS];
81 	struct tipc_bcbearer_pair bpairs_temp[TIPC_MAX_LINK_PRI + 1];
82 	struct tipc_node_map remains;
83 	struct tipc_node_map remains_new;
84 };
85 
86 /**
87  * struct tipc_bclink - link used for broadcast messages
88  * @link: (non-standard) broadcast link structure
89  * @node: (non-standard) node structure representing b'cast link's peer node
90  * @bcast_nodes: map of broadcast-capable nodes
91  * @retransmit_to: node that most recently requested a retransmit
92  *
93  * Handles sequence numbering, fragmentation, bundling, etc.
94  */
95 
96 struct tipc_bclink {
97 	struct tipc_link link;
98 	struct tipc_node node;
99 	struct tipc_node_map bcast_nodes;
100 	struct tipc_node *retransmit_to;
101 };
102 
103 static struct tipc_bcbearer bcast_bearer;
104 static struct tipc_bclink bcast_link;
105 
106 static struct tipc_bcbearer *bcbearer = &bcast_bearer;
107 static struct tipc_bclink *bclink = &bcast_link;
108 static struct tipc_link *bcl = &bcast_link.link;
109 
110 static DEFINE_SPINLOCK(bc_lock);
111 
112 const char tipc_bclink_name[] = "broadcast-link";
113 
114 static void tipc_nmap_diff(struct tipc_node_map *nm_a,
115 			   struct tipc_node_map *nm_b,
116 			   struct tipc_node_map *nm_diff);
117 
118 static u32 bcbuf_acks(struct sk_buff *buf)
119 {
120 	return (u32)(unsigned long)TIPC_SKB_CB(buf)->handle;
121 }
122 
123 static void bcbuf_set_acks(struct sk_buff *buf, u32 acks)
124 {
125 	TIPC_SKB_CB(buf)->handle = (void *)(unsigned long)acks;
126 }
127 
128 static void bcbuf_decr_acks(struct sk_buff *buf)
129 {
130 	bcbuf_set_acks(buf, bcbuf_acks(buf) - 1);
131 }
132 
133 void tipc_bclink_add_node(u32 addr)
134 {
135 	spin_lock_bh(&bc_lock);
136 	tipc_nmap_add(&bclink->bcast_nodes, addr);
137 	spin_unlock_bh(&bc_lock);
138 }
139 
140 void tipc_bclink_remove_node(u32 addr)
141 {
142 	spin_lock_bh(&bc_lock);
143 	tipc_nmap_remove(&bclink->bcast_nodes, addr);
144 	spin_unlock_bh(&bc_lock);
145 }
146 
147 static void bclink_set_last_sent(void)
148 {
149 	if (bcl->next_out)
150 		bcl->fsm_msg_cnt = mod(buf_seqno(bcl->next_out) - 1);
151 	else
152 		bcl->fsm_msg_cnt = mod(bcl->next_out_no - 1);
153 }
154 
155 u32 tipc_bclink_get_last_sent(void)
156 {
157 	return bcl->fsm_msg_cnt;
158 }
159 
160 /**
161  * bclink_set_gap - set gap according to contents of current deferred pkt queue
162  *
163  * Called with 'node' locked, bc_lock unlocked
164  */
165 
166 static void bclink_set_gap(struct tipc_node *n_ptr)
167 {
168 	struct sk_buff *buf = n_ptr->bclink.deferred_head;
169 
170 	n_ptr->bclink.gap_after = n_ptr->bclink.gap_to =
171 		mod(n_ptr->bclink.last_in);
172 	if (unlikely(buf != NULL))
173 		n_ptr->bclink.gap_to = mod(buf_seqno(buf) - 1);
174 }
175 
176 /**
177  * bclink_ack_allowed - test if ACK or NACK message can be sent at this moment
178  *
179  * This mechanism endeavours to prevent all nodes in network from trying
180  * to ACK or NACK at the same time.
181  *
182  * Note: TIPC uses a different trigger to distribute ACKs than it does to
183  *       distribute NACKs, but tries to use the same spacing (divide by 16).
184  */
185 
186 static int bclink_ack_allowed(u32 n)
187 {
188 	return (n % TIPC_MIN_LINK_WIN) == tipc_own_tag;
189 }
190 
191 
192 /**
193  * tipc_bclink_retransmit_to - get most recent node to request retransmission
194  *
195  * Called with bc_lock locked
196  */
197 
198 struct tipc_node *tipc_bclink_retransmit_to(void)
199 {
200 	return bclink->retransmit_to;
201 }
202 
203 /**
204  * bclink_retransmit_pkt - retransmit broadcast packets
205  * @after: sequence number of last packet to *not* retransmit
206  * @to: sequence number of last packet to retransmit
207  *
208  * Called with bc_lock locked
209  */
210 
211 static void bclink_retransmit_pkt(u32 after, u32 to)
212 {
213 	struct sk_buff *buf;
214 
215 	buf = bcl->first_out;
216 	while (buf && less_eq(buf_seqno(buf), after))
217 		buf = buf->next;
218 	tipc_link_retransmit(bcl, buf, mod(to - after));
219 }
220 
221 /**
222  * tipc_bclink_acknowledge - handle acknowledgement of broadcast packets
223  * @n_ptr: node that sent acknowledgement info
224  * @acked: broadcast sequence # that has been acknowledged
225  *
226  * Node is locked, bc_lock unlocked.
227  */
228 
229 void tipc_bclink_acknowledge(struct tipc_node *n_ptr, u32 acked)
230 {
231 	struct sk_buff *crs;
232 	struct sk_buff *next;
233 	unsigned int released = 0;
234 
235 	spin_lock_bh(&bc_lock);
236 
237 	/* Bail out if tx queue is empty (no clean up is required) */
238 	crs = bcl->first_out;
239 	if (!crs)
240 		goto exit;
241 
242 	/* Determine which messages need to be acknowledged */
243 	if (acked == INVALID_LINK_SEQ) {
244 		/*
245 		 * Contact with specified node has been lost, so need to
246 		 * acknowledge sent messages only (if other nodes still exist)
247 		 * or both sent and unsent messages (otherwise)
248 		 */
249 		if (bclink->bcast_nodes.count)
250 			acked = bcl->fsm_msg_cnt;
251 		else
252 			acked = bcl->next_out_no;
253 	} else {
254 		/*
255 		 * Bail out if specified sequence number does not correspond
256 		 * to a message that has been sent and not yet acknowledged
257 		 */
258 		if (less(acked, buf_seqno(crs)) ||
259 		    less(bcl->fsm_msg_cnt, acked) ||
260 		    less_eq(acked, n_ptr->bclink.acked))
261 			goto exit;
262 	}
263 
264 	/* Skip over packets that node has previously acknowledged */
265 	while (crs && less_eq(buf_seqno(crs), n_ptr->bclink.acked))
266 		crs = crs->next;
267 
268 	/* Update packets that node is now acknowledging */
269 
270 	while (crs && less_eq(buf_seqno(crs), acked)) {
271 		next = crs->next;
272 
273 		if (crs != bcl->next_out)
274 			bcbuf_decr_acks(crs);
275 		else {
276 			bcbuf_set_acks(crs, 0);
277 			bcl->next_out = next;
278 			bclink_set_last_sent();
279 		}
280 
281 		if (bcbuf_acks(crs) == 0) {
282 			bcl->first_out = next;
283 			bcl->out_queue_size--;
284 			buf_discard(crs);
285 			released = 1;
286 		}
287 		crs = next;
288 	}
289 	n_ptr->bclink.acked = acked;
290 
291 	/* Try resolving broadcast link congestion, if necessary */
292 
293 	if (unlikely(bcl->next_out)) {
294 		tipc_link_push_queue(bcl);
295 		bclink_set_last_sent();
296 	}
297 	if (unlikely(released && !list_empty(&bcl->waiting_ports)))
298 		tipc_link_wakeup_ports(bcl, 0);
299 exit:
300 	spin_unlock_bh(&bc_lock);
301 }
302 
303 /**
304  * bclink_send_ack - unicast an ACK msg
305  *
306  * tipc_net_lock and node lock set
307  */
308 
309 static void bclink_send_ack(struct tipc_node *n_ptr)
310 {
311 	struct tipc_link *l_ptr = n_ptr->active_links[n_ptr->addr & 1];
312 
313 	if (l_ptr != NULL)
314 		tipc_link_send_proto_msg(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
315 }
316 
317 /**
318  * bclink_send_nack- broadcast a NACK msg
319  *
320  * tipc_net_lock and node lock set
321  */
322 
323 static void bclink_send_nack(struct tipc_node *n_ptr)
324 {
325 	struct sk_buff *buf;
326 	struct tipc_msg *msg;
327 
328 	if (!less(n_ptr->bclink.gap_after, n_ptr->bclink.gap_to))
329 		return;
330 
331 	buf = tipc_buf_acquire(INT_H_SIZE);
332 	if (buf) {
333 		msg = buf_msg(buf);
334 		tipc_msg_init(msg, BCAST_PROTOCOL, STATE_MSG,
335 			 INT_H_SIZE, n_ptr->addr);
336 		msg_set_non_seq(msg, 1);
337 		msg_set_mc_netid(msg, tipc_net_id);
338 		msg_set_bcast_ack(msg, mod(n_ptr->bclink.last_in));
339 		msg_set_bcgap_after(msg, n_ptr->bclink.gap_after);
340 		msg_set_bcgap_to(msg, n_ptr->bclink.gap_to);
341 		msg_set_bcast_tag(msg, tipc_own_tag);
342 
343 		tipc_bearer_send(&bcbearer->bearer, buf, NULL);
344 		bcl->stats.sent_nacks++;
345 		buf_discard(buf);
346 
347 		/*
348 		 * Ensure we doesn't send another NACK msg to the node
349 		 * until 16 more deferred messages arrive from it
350 		 * (i.e. helps prevent all nodes from NACK'ing at same time)
351 		 */
352 
353 		n_ptr->bclink.nack_sync = tipc_own_tag;
354 	}
355 }
356 
357 /**
358  * tipc_bclink_check_gap - send a NACK if a sequence gap exists
359  *
360  * tipc_net_lock and node lock set
361  */
362 
363 void tipc_bclink_check_gap(struct tipc_node *n_ptr, u32 last_sent)
364 {
365 	if (!n_ptr->bclink.supported ||
366 	    less_eq(last_sent, mod(n_ptr->bclink.last_in)))
367 		return;
368 
369 	bclink_set_gap(n_ptr);
370 	if (n_ptr->bclink.gap_after == n_ptr->bclink.gap_to)
371 		n_ptr->bclink.gap_to = last_sent;
372 	bclink_send_nack(n_ptr);
373 }
374 
375 /**
376  * tipc_bclink_peek_nack - process a NACK msg meant for another node
377  *
378  * Only tipc_net_lock set.
379  */
380 
381 static void tipc_bclink_peek_nack(u32 dest, u32 sender_tag, u32 gap_after, u32 gap_to)
382 {
383 	struct tipc_node *n_ptr = tipc_node_find(dest);
384 	u32 my_after, my_to;
385 
386 	if (unlikely(!n_ptr || !tipc_node_is_up(n_ptr)))
387 		return;
388 	tipc_node_lock(n_ptr);
389 	/*
390 	 * Modify gap to suppress unnecessary NACKs from this node
391 	 */
392 	my_after = n_ptr->bclink.gap_after;
393 	my_to = n_ptr->bclink.gap_to;
394 
395 	if (less_eq(gap_after, my_after)) {
396 		if (less(my_after, gap_to) && less(gap_to, my_to))
397 			n_ptr->bclink.gap_after = gap_to;
398 		else if (less_eq(my_to, gap_to))
399 			n_ptr->bclink.gap_to = n_ptr->bclink.gap_after;
400 	} else if (less_eq(gap_after, my_to)) {
401 		if (less_eq(my_to, gap_to))
402 			n_ptr->bclink.gap_to = gap_after;
403 	} else {
404 		/*
405 		 * Expand gap if missing bufs not in deferred queue:
406 		 */
407 		struct sk_buff *buf = n_ptr->bclink.deferred_head;
408 		u32 prev = n_ptr->bclink.gap_to;
409 
410 		for (; buf; buf = buf->next) {
411 			u32 seqno = buf_seqno(buf);
412 
413 			if (mod(seqno - prev) != 1) {
414 				buf = NULL;
415 				break;
416 			}
417 			if (seqno == gap_after)
418 				break;
419 			prev = seqno;
420 		}
421 		if (buf == NULL)
422 			n_ptr->bclink.gap_to = gap_after;
423 	}
424 	/*
425 	 * Some nodes may send a complementary NACK now:
426 	 */
427 	if (bclink_ack_allowed(sender_tag + 1)) {
428 		if (n_ptr->bclink.gap_to != n_ptr->bclink.gap_after) {
429 			bclink_send_nack(n_ptr);
430 			bclink_set_gap(n_ptr);
431 		}
432 	}
433 	tipc_node_unlock(n_ptr);
434 }
435 
436 /**
437  * tipc_bclink_send_msg - broadcast a packet to all nodes in cluster
438  */
439 
440 int tipc_bclink_send_msg(struct sk_buff *buf)
441 {
442 	int res;
443 
444 	spin_lock_bh(&bc_lock);
445 
446 	if (!bclink->bcast_nodes.count) {
447 		res = msg_data_sz(buf_msg(buf));
448 		buf_discard(buf);
449 		goto exit;
450 	}
451 
452 	res = tipc_link_send_buf(bcl, buf);
453 	if (likely(res >= 0)) {
454 		bclink_set_last_sent();
455 		bcl->stats.queue_sz_counts++;
456 		bcl->stats.accu_queue_sz += bcl->out_queue_size;
457 	}
458 exit:
459 	spin_unlock_bh(&bc_lock);
460 	return res;
461 }
462 
463 /**
464  * tipc_bclink_recv_pkt - receive a broadcast packet, and deliver upwards
465  *
466  * tipc_net_lock is read_locked, no other locks set
467  */
468 
469 void tipc_bclink_recv_pkt(struct sk_buff *buf)
470 {
471 	struct tipc_msg *msg = buf_msg(buf);
472 	struct tipc_node *node;
473 	u32 next_in;
474 	u32 seqno;
475 	struct sk_buff *deferred;
476 
477 	/* Screen out unwanted broadcast messages */
478 
479 	if (msg_mc_netid(msg) != tipc_net_id)
480 		goto exit;
481 
482 	node = tipc_node_find(msg_prevnode(msg));
483 	if (unlikely(!node))
484 		goto exit;
485 
486 	tipc_node_lock(node);
487 	if (unlikely(!node->bclink.supported))
488 		goto unlock;
489 
490 	if (unlikely(msg_user(msg) == BCAST_PROTOCOL)) {
491 		if (msg_type(msg) != STATE_MSG)
492 			goto unlock;
493 		if (msg_destnode(msg) == tipc_own_addr) {
494 			tipc_bclink_acknowledge(node, msg_bcast_ack(msg));
495 			tipc_node_unlock(node);
496 			spin_lock_bh(&bc_lock);
497 			bcl->stats.recv_nacks++;
498 			bclink->retransmit_to = node;
499 			bclink_retransmit_pkt(msg_bcgap_after(msg),
500 					      msg_bcgap_to(msg));
501 			spin_unlock_bh(&bc_lock);
502 		} else {
503 			tipc_node_unlock(node);
504 			tipc_bclink_peek_nack(msg_destnode(msg),
505 					      msg_bcast_tag(msg),
506 					      msg_bcgap_after(msg),
507 					      msg_bcgap_to(msg));
508 		}
509 		goto exit;
510 	}
511 
512 	/* Handle in-sequence broadcast message */
513 
514 receive:
515 	next_in = mod(node->bclink.last_in + 1);
516 	seqno = msg_seqno(msg);
517 
518 	if (likely(seqno == next_in)) {
519 		bcl->stats.recv_info++;
520 		node->bclink.last_in++;
521 		bclink_set_gap(node);
522 		if (unlikely(bclink_ack_allowed(seqno))) {
523 			bclink_send_ack(node);
524 			bcl->stats.sent_acks++;
525 		}
526 		if (likely(msg_isdata(msg))) {
527 			tipc_node_unlock(node);
528 			if (likely(msg_mcast(msg)))
529 				tipc_port_recv_mcast(buf, NULL);
530 			else
531 				buf_discard(buf);
532 		} else if (msg_user(msg) == MSG_BUNDLER) {
533 			bcl->stats.recv_bundles++;
534 			bcl->stats.recv_bundled += msg_msgcnt(msg);
535 			tipc_node_unlock(node);
536 			tipc_link_recv_bundle(buf);
537 		} else if (msg_user(msg) == MSG_FRAGMENTER) {
538 			bcl->stats.recv_fragments++;
539 			if (tipc_link_recv_fragment(&node->bclink.defragm,
540 						    &buf, &msg))
541 				bcl->stats.recv_fragmented++;
542 			tipc_node_unlock(node);
543 			tipc_net_route_msg(buf);
544 		} else if (msg_user(msg) == NAME_DISTRIBUTOR) {
545 			tipc_node_unlock(node);
546 			tipc_named_recv(buf);
547 		} else {
548 			tipc_node_unlock(node);
549 			buf_discard(buf);
550 		}
551 		buf = NULL;
552 		tipc_node_lock(node);
553 		deferred = node->bclink.deferred_head;
554 		if (deferred && (buf_seqno(deferred) == mod(next_in + 1))) {
555 			buf = deferred;
556 			msg = buf_msg(buf);
557 			node->bclink.deferred_head = deferred->next;
558 			goto receive;
559 		}
560 	} else if (less(next_in, seqno)) {
561 		u32 gap_after = node->bclink.gap_after;
562 		u32 gap_to = node->bclink.gap_to;
563 
564 		if (tipc_link_defer_pkt(&node->bclink.deferred_head,
565 					&node->bclink.deferred_tail,
566 					buf)) {
567 			node->bclink.nack_sync++;
568 			bcl->stats.deferred_recv++;
569 			if (seqno == mod(gap_after + 1))
570 				node->bclink.gap_after = seqno;
571 			else if (less(gap_after, seqno) && less(seqno, gap_to))
572 				node->bclink.gap_to = seqno;
573 		}
574 		buf = NULL;
575 		if (bclink_ack_allowed(node->bclink.nack_sync)) {
576 			if (gap_to != gap_after)
577 				bclink_send_nack(node);
578 			bclink_set_gap(node);
579 		}
580 	} else {
581 		bcl->stats.duplicates++;
582 	}
583 unlock:
584 	tipc_node_unlock(node);
585 exit:
586 	buf_discard(buf);
587 }
588 
589 u32 tipc_bclink_acks_missing(struct tipc_node *n_ptr)
590 {
591 	return (n_ptr->bclink.supported &&
592 		(tipc_bclink_get_last_sent() != n_ptr->bclink.acked));
593 }
594 
595 
596 /**
597  * tipc_bcbearer_send - send a packet through the broadcast pseudo-bearer
598  *
599  * Send packet over as many bearers as necessary to reach all nodes
600  * that have joined the broadcast link.
601  *
602  * Returns 0 (packet sent successfully) under all circumstances,
603  * since the broadcast link's pseudo-bearer never blocks
604  */
605 
606 static int tipc_bcbearer_send(struct sk_buff *buf,
607 			      struct tipc_bearer *unused1,
608 			      struct tipc_media_addr *unused2)
609 {
610 	int bp_index;
611 
612 	/*
613 	 * Prepare broadcast link message for reliable transmission,
614 	 * if first time trying to send it;
615 	 * preparation is skipped for broadcast link protocol messages
616 	 * since they are sent in an unreliable manner and don't need it
617 	 */
618 
619 	if (likely(!msg_non_seq(buf_msg(buf)))) {
620 		struct tipc_msg *msg;
621 
622 		bcbuf_set_acks(buf, bclink->bcast_nodes.count);
623 		msg = buf_msg(buf);
624 		msg_set_non_seq(msg, 1);
625 		msg_set_mc_netid(msg, tipc_net_id);
626 		bcl->stats.sent_info++;
627 
628 		if (WARN_ON(!bclink->bcast_nodes.count)) {
629 			dump_stack();
630 			return 0;
631 		}
632 	}
633 
634 	/* Send buffer over bearers until all targets reached */
635 
636 	bcbearer->remains = bclink->bcast_nodes;
637 
638 	for (bp_index = 0; bp_index < MAX_BEARERS; bp_index++) {
639 		struct tipc_bearer *p = bcbearer->bpairs[bp_index].primary;
640 		struct tipc_bearer *s = bcbearer->bpairs[bp_index].secondary;
641 
642 		if (!p)
643 			break;	/* no more bearers to try */
644 
645 		tipc_nmap_diff(&bcbearer->remains, &p->nodes, &bcbearer->remains_new);
646 		if (bcbearer->remains_new.count == bcbearer->remains.count)
647 			continue;	/* bearer pair doesn't add anything */
648 
649 		if (p->blocked ||
650 		    p->media->send_msg(buf, p, &p->media->bcast_addr)) {
651 			/* unable to send on primary bearer */
652 			if (!s || s->blocked ||
653 			    s->media->send_msg(buf, s,
654 					       &s->media->bcast_addr)) {
655 				/* unable to send on either bearer */
656 				continue;
657 			}
658 		}
659 
660 		if (s) {
661 			bcbearer->bpairs[bp_index].primary = s;
662 			bcbearer->bpairs[bp_index].secondary = p;
663 		}
664 
665 		if (bcbearer->remains_new.count == 0)
666 			break;	/* all targets reached */
667 
668 		bcbearer->remains = bcbearer->remains_new;
669 	}
670 
671 	return 0;
672 }
673 
674 /**
675  * tipc_bcbearer_sort - create sets of bearer pairs used by broadcast bearer
676  */
677 
678 void tipc_bcbearer_sort(void)
679 {
680 	struct tipc_bcbearer_pair *bp_temp = bcbearer->bpairs_temp;
681 	struct tipc_bcbearer_pair *bp_curr;
682 	int b_index;
683 	int pri;
684 
685 	spin_lock_bh(&bc_lock);
686 
687 	/* Group bearers by priority (can assume max of two per priority) */
688 
689 	memset(bp_temp, 0, sizeof(bcbearer->bpairs_temp));
690 
691 	for (b_index = 0; b_index < MAX_BEARERS; b_index++) {
692 		struct tipc_bearer *b = &tipc_bearers[b_index];
693 
694 		if (!b->active || !b->nodes.count)
695 			continue;
696 
697 		if (!bp_temp[b->priority].primary)
698 			bp_temp[b->priority].primary = b;
699 		else
700 			bp_temp[b->priority].secondary = b;
701 	}
702 
703 	/* Create array of bearer pairs for broadcasting */
704 
705 	bp_curr = bcbearer->bpairs;
706 	memset(bcbearer->bpairs, 0, sizeof(bcbearer->bpairs));
707 
708 	for (pri = TIPC_MAX_LINK_PRI; pri >= 0; pri--) {
709 
710 		if (!bp_temp[pri].primary)
711 			continue;
712 
713 		bp_curr->primary = bp_temp[pri].primary;
714 
715 		if (bp_temp[pri].secondary) {
716 			if (tipc_nmap_equal(&bp_temp[pri].primary->nodes,
717 					    &bp_temp[pri].secondary->nodes)) {
718 				bp_curr->secondary = bp_temp[pri].secondary;
719 			} else {
720 				bp_curr++;
721 				bp_curr->primary = bp_temp[pri].secondary;
722 			}
723 		}
724 
725 		bp_curr++;
726 	}
727 
728 	spin_unlock_bh(&bc_lock);
729 }
730 
731 
732 int tipc_bclink_stats(char *buf, const u32 buf_size)
733 {
734 	struct print_buf pb;
735 
736 	if (!bcl)
737 		return 0;
738 
739 	tipc_printbuf_init(&pb, buf, buf_size);
740 
741 	spin_lock_bh(&bc_lock);
742 
743 	tipc_printf(&pb, "Link <%s>\n"
744 			 "  Window:%u packets\n",
745 		    bcl->name, bcl->queue_limit[0]);
746 	tipc_printf(&pb, "  RX packets:%u fragments:%u/%u bundles:%u/%u\n",
747 		    bcl->stats.recv_info,
748 		    bcl->stats.recv_fragments,
749 		    bcl->stats.recv_fragmented,
750 		    bcl->stats.recv_bundles,
751 		    bcl->stats.recv_bundled);
752 	tipc_printf(&pb, "  TX packets:%u fragments:%u/%u bundles:%u/%u\n",
753 		    bcl->stats.sent_info,
754 		    bcl->stats.sent_fragments,
755 		    bcl->stats.sent_fragmented,
756 		    bcl->stats.sent_bundles,
757 		    bcl->stats.sent_bundled);
758 	tipc_printf(&pb, "  RX naks:%u defs:%u dups:%u\n",
759 		    bcl->stats.recv_nacks,
760 		    bcl->stats.deferred_recv,
761 		    bcl->stats.duplicates);
762 	tipc_printf(&pb, "  TX naks:%u acks:%u dups:%u\n",
763 		    bcl->stats.sent_nacks,
764 		    bcl->stats.sent_acks,
765 		    bcl->stats.retransmitted);
766 	tipc_printf(&pb, "  Congestion bearer:%u link:%u  Send queue max:%u avg:%u\n",
767 		    bcl->stats.bearer_congs,
768 		    bcl->stats.link_congs,
769 		    bcl->stats.max_queue_sz,
770 		    bcl->stats.queue_sz_counts
771 		    ? (bcl->stats.accu_queue_sz / bcl->stats.queue_sz_counts)
772 		    : 0);
773 
774 	spin_unlock_bh(&bc_lock);
775 	return tipc_printbuf_validate(&pb);
776 }
777 
778 int tipc_bclink_reset_stats(void)
779 {
780 	if (!bcl)
781 		return -ENOPROTOOPT;
782 
783 	spin_lock_bh(&bc_lock);
784 	memset(&bcl->stats, 0, sizeof(bcl->stats));
785 	spin_unlock_bh(&bc_lock);
786 	return 0;
787 }
788 
789 int tipc_bclink_set_queue_limits(u32 limit)
790 {
791 	if (!bcl)
792 		return -ENOPROTOOPT;
793 	if ((limit < TIPC_MIN_LINK_WIN) || (limit > TIPC_MAX_LINK_WIN))
794 		return -EINVAL;
795 
796 	spin_lock_bh(&bc_lock);
797 	tipc_link_set_queue_limits(bcl, limit);
798 	spin_unlock_bh(&bc_lock);
799 	return 0;
800 }
801 
802 void tipc_bclink_init(void)
803 {
804 	INIT_LIST_HEAD(&bcbearer->bearer.cong_links);
805 	bcbearer->bearer.media = &bcbearer->media;
806 	bcbearer->media.send_msg = tipc_bcbearer_send;
807 	sprintf(bcbearer->media.name, "tipc-broadcast");
808 
809 	INIT_LIST_HEAD(&bcl->waiting_ports);
810 	bcl->next_out_no = 1;
811 	spin_lock_init(&bclink->node.lock);
812 	bcl->owner = &bclink->node;
813 	bcl->max_pkt = MAX_PKT_DEFAULT_MCAST;
814 	tipc_link_set_queue_limits(bcl, BCLINK_WIN_DEFAULT);
815 	bcl->b_ptr = &bcbearer->bearer;
816 	bcl->state = WORKING_WORKING;
817 	strlcpy(bcl->name, tipc_bclink_name, TIPC_MAX_LINK_NAME);
818 }
819 
820 void tipc_bclink_stop(void)
821 {
822 	spin_lock_bh(&bc_lock);
823 	tipc_link_stop(bcl);
824 	spin_unlock_bh(&bc_lock);
825 
826 	memset(bclink, 0, sizeof(*bclink));
827 	memset(bcbearer, 0, sizeof(*bcbearer));
828 }
829 
830 
831 /**
832  * tipc_nmap_add - add a node to a node map
833  */
834 
835 void tipc_nmap_add(struct tipc_node_map *nm_ptr, u32 node)
836 {
837 	int n = tipc_node(node);
838 	int w = n / WSIZE;
839 	u32 mask = (1 << (n % WSIZE));
840 
841 	if ((nm_ptr->map[w] & mask) == 0) {
842 		nm_ptr->count++;
843 		nm_ptr->map[w] |= mask;
844 	}
845 }
846 
847 /**
848  * tipc_nmap_remove - remove a node from a node map
849  */
850 
851 void tipc_nmap_remove(struct tipc_node_map *nm_ptr, u32 node)
852 {
853 	int n = tipc_node(node);
854 	int w = n / WSIZE;
855 	u32 mask = (1 << (n % WSIZE));
856 
857 	if ((nm_ptr->map[w] & mask) != 0) {
858 		nm_ptr->map[w] &= ~mask;
859 		nm_ptr->count--;
860 	}
861 }
862 
863 /**
864  * tipc_nmap_diff - find differences between node maps
865  * @nm_a: input node map A
866  * @nm_b: input node map B
867  * @nm_diff: output node map A-B (i.e. nodes of A that are not in B)
868  */
869 
870 static void tipc_nmap_diff(struct tipc_node_map *nm_a,
871 			   struct tipc_node_map *nm_b,
872 			   struct tipc_node_map *nm_diff)
873 {
874 	int stop = ARRAY_SIZE(nm_a->map);
875 	int w;
876 	int b;
877 	u32 map;
878 
879 	memset(nm_diff, 0, sizeof(*nm_diff));
880 	for (w = 0; w < stop; w++) {
881 		map = nm_a->map[w] ^ (nm_a->map[w] & nm_b->map[w]);
882 		nm_diff->map[w] = map;
883 		if (map != 0) {
884 			for (b = 0 ; b < WSIZE; b++) {
885 				if (map & (1 << b))
886 					nm_diff->count++;
887 			}
888 		}
889 	}
890 }
891 
892 /**
893  * tipc_port_list_add - add a port to a port list, ensuring no duplicates
894  */
895 
896 void tipc_port_list_add(struct tipc_port_list *pl_ptr, u32 port)
897 {
898 	struct tipc_port_list *item = pl_ptr;
899 	int i;
900 	int item_sz = PLSIZE;
901 	int cnt = pl_ptr->count;
902 
903 	for (; ; cnt -= item_sz, item = item->next) {
904 		if (cnt < PLSIZE)
905 			item_sz = cnt;
906 		for (i = 0; i < item_sz; i++)
907 			if (item->ports[i] == port)
908 				return;
909 		if (i < PLSIZE) {
910 			item->ports[i] = port;
911 			pl_ptr->count++;
912 			return;
913 		}
914 		if (!item->next) {
915 			item->next = kmalloc(sizeof(*item), GFP_ATOMIC);
916 			if (!item->next) {
917 				warn("Incomplete multicast delivery, no memory\n");
918 				return;
919 			}
920 			item->next->next = NULL;
921 		}
922 	}
923 }
924 
925 /**
926  * tipc_port_list_free - free dynamically created entries in port_list chain
927  *
928  */
929 
930 void tipc_port_list_free(struct tipc_port_list *pl_ptr)
931 {
932 	struct tipc_port_list *item;
933 	struct tipc_port_list *next;
934 
935 	for (item = pl_ptr->next; item; item = next) {
936 		next = item->next;
937 		kfree(item);
938 	}
939 }
940 
941