xref: /openbmc/linux/net/tipc/link.c (revision afb46f79)
1 /*
2  * net/tipc/link.c: TIPC link code
3  *
4  * Copyright (c) 1996-2007, 2012-2014, Ericsson AB
5  * Copyright (c) 2004-2007, 2010-2013, 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 #include <linux/pkt_sched.h>
45 
46 /*
47  * Error message prefixes
48  */
49 static const char *link_co_err = "Link changeover error, ";
50 static const char *link_rst_msg = "Resetting link ";
51 static const char *link_unk_evt = "Unknown link event ";
52 
53 /*
54  * Out-of-range value for link session numbers
55  */
56 #define INVALID_SESSION 0x10000
57 
58 /*
59  * Link state events:
60  */
61 #define  STARTING_EVT    856384768	/* link processing trigger */
62 #define  TRAFFIC_MSG_EVT 560815u	/* rx'd ??? */
63 #define  TIMEOUT_EVT     560817u	/* link timer expired */
64 
65 /*
66  * The following two 'message types' is really just implementation
67  * data conveniently stored in the message header.
68  * They must not be considered part of the protocol
69  */
70 #define OPEN_MSG   0
71 #define CLOSED_MSG 1
72 
73 /*
74  * State value stored in 'exp_msg_count'
75  */
76 #define START_CHANGEOVER 100000u
77 
78 static void link_handle_out_of_seq_msg(struct tipc_link *l_ptr,
79 				       struct sk_buff *buf);
80 static void tipc_link_proto_rcv(struct tipc_link *l_ptr, struct sk_buff *buf);
81 static int  tipc_link_tunnel_rcv(struct tipc_node *n_ptr,
82 				 struct sk_buff **buf);
83 static void link_set_supervision_props(struct tipc_link *l_ptr, u32 tolerance);
84 static int  tipc_link_iovec_long_xmit(struct tipc_port *sender,
85 				      struct iovec const *msg_sect,
86 				      unsigned int len, u32 destnode);
87 static void link_state_event(struct tipc_link *l_ptr, u32 event);
88 static void link_reset_statistics(struct tipc_link *l_ptr);
89 static void link_print(struct tipc_link *l_ptr, const char *str);
90 static int tipc_link_frag_xmit(struct tipc_link *l_ptr, struct sk_buff *buf);
91 static void tipc_link_sync_xmit(struct tipc_link *l);
92 static void tipc_link_sync_rcv(struct tipc_node *n, struct sk_buff *buf);
93 
94 /*
95  *  Simple link routines
96  */
97 static unsigned int align(unsigned int i)
98 {
99 	return (i + 3) & ~3u;
100 }
101 
102 static void link_init_max_pkt(struct tipc_link *l_ptr)
103 {
104 	u32 max_pkt;
105 
106 	max_pkt = (l_ptr->b_ptr->mtu & ~3);
107 	if (max_pkt > MAX_MSG_SIZE)
108 		max_pkt = MAX_MSG_SIZE;
109 
110 	l_ptr->max_pkt_target = max_pkt;
111 	if (l_ptr->max_pkt_target < MAX_PKT_DEFAULT)
112 		l_ptr->max_pkt = l_ptr->max_pkt_target;
113 	else
114 		l_ptr->max_pkt = MAX_PKT_DEFAULT;
115 
116 	l_ptr->max_pkt_probes = 0;
117 }
118 
119 static u32 link_next_sent(struct tipc_link *l_ptr)
120 {
121 	if (l_ptr->next_out)
122 		return buf_seqno(l_ptr->next_out);
123 	return mod(l_ptr->next_out_no);
124 }
125 
126 static u32 link_last_sent(struct tipc_link *l_ptr)
127 {
128 	return mod(link_next_sent(l_ptr) - 1);
129 }
130 
131 /*
132  *  Simple non-static link routines (i.e. referenced outside this file)
133  */
134 int tipc_link_is_up(struct tipc_link *l_ptr)
135 {
136 	if (!l_ptr)
137 		return 0;
138 	return link_working_working(l_ptr) || link_working_unknown(l_ptr);
139 }
140 
141 int tipc_link_is_active(struct tipc_link *l_ptr)
142 {
143 	return	(l_ptr->owner->active_links[0] == l_ptr) ||
144 		(l_ptr->owner->active_links[1] == l_ptr);
145 }
146 
147 /**
148  * link_timeout - handle expiration of link timer
149  * @l_ptr: pointer to link
150  */
151 static void link_timeout(struct tipc_link *l_ptr)
152 {
153 	tipc_node_lock(l_ptr->owner);
154 
155 	/* update counters used in statistical profiling of send traffic */
156 	l_ptr->stats.accu_queue_sz += l_ptr->out_queue_size;
157 	l_ptr->stats.queue_sz_counts++;
158 
159 	if (l_ptr->first_out) {
160 		struct tipc_msg *msg = buf_msg(l_ptr->first_out);
161 		u32 length = msg_size(msg);
162 
163 		if ((msg_user(msg) == MSG_FRAGMENTER) &&
164 		    (msg_type(msg) == FIRST_FRAGMENT)) {
165 			length = msg_size(msg_get_wrapped(msg));
166 		}
167 		if (length) {
168 			l_ptr->stats.msg_lengths_total += length;
169 			l_ptr->stats.msg_length_counts++;
170 			if (length <= 64)
171 				l_ptr->stats.msg_length_profile[0]++;
172 			else if (length <= 256)
173 				l_ptr->stats.msg_length_profile[1]++;
174 			else if (length <= 1024)
175 				l_ptr->stats.msg_length_profile[2]++;
176 			else if (length <= 4096)
177 				l_ptr->stats.msg_length_profile[3]++;
178 			else if (length <= 16384)
179 				l_ptr->stats.msg_length_profile[4]++;
180 			else if (length <= 32768)
181 				l_ptr->stats.msg_length_profile[5]++;
182 			else
183 				l_ptr->stats.msg_length_profile[6]++;
184 		}
185 	}
186 
187 	/* do all other link processing performed on a periodic basis */
188 
189 	link_state_event(l_ptr, TIMEOUT_EVT);
190 
191 	if (l_ptr->next_out)
192 		tipc_link_push_queue(l_ptr);
193 
194 	tipc_node_unlock(l_ptr->owner);
195 }
196 
197 static void link_set_timer(struct tipc_link *l_ptr, u32 time)
198 {
199 	k_start_timer(&l_ptr->timer, time);
200 }
201 
202 /**
203  * tipc_link_create - create a new link
204  * @n_ptr: pointer to associated node
205  * @b_ptr: pointer to associated bearer
206  * @media_addr: media address to use when sending messages over link
207  *
208  * Returns pointer to link.
209  */
210 struct tipc_link *tipc_link_create(struct tipc_node *n_ptr,
211 				   struct tipc_bearer *b_ptr,
212 				   const struct tipc_media_addr *media_addr)
213 {
214 	struct tipc_link *l_ptr;
215 	struct tipc_msg *msg;
216 	char *if_name;
217 	char addr_string[16];
218 	u32 peer = n_ptr->addr;
219 
220 	if (n_ptr->link_cnt >= 2) {
221 		tipc_addr_string_fill(addr_string, n_ptr->addr);
222 		pr_err("Attempt to establish third link to %s\n", addr_string);
223 		return NULL;
224 	}
225 
226 	if (n_ptr->links[b_ptr->identity]) {
227 		tipc_addr_string_fill(addr_string, n_ptr->addr);
228 		pr_err("Attempt to establish second link on <%s> to %s\n",
229 		       b_ptr->name, addr_string);
230 		return NULL;
231 	}
232 
233 	l_ptr = kzalloc(sizeof(*l_ptr), GFP_ATOMIC);
234 	if (!l_ptr) {
235 		pr_warn("Link creation failed, no memory\n");
236 		return NULL;
237 	}
238 
239 	l_ptr->addr = peer;
240 	if_name = strchr(b_ptr->name, ':') + 1;
241 	sprintf(l_ptr->name, "%u.%u.%u:%s-%u.%u.%u:unknown",
242 		tipc_zone(tipc_own_addr), tipc_cluster(tipc_own_addr),
243 		tipc_node(tipc_own_addr),
244 		if_name,
245 		tipc_zone(peer), tipc_cluster(peer), tipc_node(peer));
246 		/* note: peer i/f name is updated by reset/activate message */
247 	memcpy(&l_ptr->media_addr, media_addr, sizeof(*media_addr));
248 	l_ptr->owner = n_ptr;
249 	l_ptr->checkpoint = 1;
250 	l_ptr->peer_session = INVALID_SESSION;
251 	l_ptr->b_ptr = b_ptr;
252 	link_set_supervision_props(l_ptr, b_ptr->tolerance);
253 	l_ptr->state = RESET_UNKNOWN;
254 
255 	l_ptr->pmsg = (struct tipc_msg *)&l_ptr->proto_msg;
256 	msg = l_ptr->pmsg;
257 	tipc_msg_init(msg, LINK_PROTOCOL, RESET_MSG, INT_H_SIZE, l_ptr->addr);
258 	msg_set_size(msg, sizeof(l_ptr->proto_msg));
259 	msg_set_session(msg, (tipc_random & 0xffff));
260 	msg_set_bearer_id(msg, b_ptr->identity);
261 	strcpy((char *)msg_data(msg), if_name);
262 
263 	l_ptr->priority = b_ptr->priority;
264 	tipc_link_set_queue_limits(l_ptr, b_ptr->window);
265 
266 	link_init_max_pkt(l_ptr);
267 
268 	l_ptr->next_out_no = 1;
269 	INIT_LIST_HEAD(&l_ptr->waiting_ports);
270 
271 	link_reset_statistics(l_ptr);
272 
273 	tipc_node_attach_link(n_ptr, l_ptr);
274 
275 	k_init_timer(&l_ptr->timer, (Handler)link_timeout,
276 		     (unsigned long)l_ptr);
277 
278 	link_state_event(l_ptr, STARTING_EVT);
279 
280 	return l_ptr;
281 }
282 
283 void tipc_link_delete_list(unsigned int bearer_id, bool shutting_down)
284 {
285 	struct tipc_link *l_ptr;
286 	struct tipc_node *n_ptr;
287 
288 	rcu_read_lock();
289 	list_for_each_entry_rcu(n_ptr, &tipc_node_list, list) {
290 		spin_lock_bh(&n_ptr->lock);
291 		l_ptr = n_ptr->links[bearer_id];
292 		if (l_ptr) {
293 			tipc_link_reset(l_ptr);
294 			if (shutting_down || !tipc_node_is_up(n_ptr)) {
295 				tipc_node_detach_link(l_ptr->owner, l_ptr);
296 				tipc_link_reset_fragments(l_ptr);
297 				spin_unlock_bh(&n_ptr->lock);
298 
299 				/* Nobody else can access this link now: */
300 				del_timer_sync(&l_ptr->timer);
301 				kfree(l_ptr);
302 			} else {
303 				/* Detach/delete when failover is finished: */
304 				l_ptr->flags |= LINK_STOPPED;
305 				spin_unlock_bh(&n_ptr->lock);
306 				del_timer_sync(&l_ptr->timer);
307 			}
308 			continue;
309 		}
310 		spin_unlock_bh(&n_ptr->lock);
311 	}
312 	rcu_read_unlock();
313 }
314 
315 /**
316  * link_schedule_port - schedule port for deferred sending
317  * @l_ptr: pointer to link
318  * @origport: reference to sending port
319  * @sz: amount of data to be sent
320  *
321  * Schedules port for renewed sending of messages after link congestion
322  * has abated.
323  */
324 static int link_schedule_port(struct tipc_link *l_ptr, u32 origport, u32 sz)
325 {
326 	struct tipc_port *p_ptr;
327 
328 	spin_lock_bh(&tipc_port_list_lock);
329 	p_ptr = tipc_port_lock(origport);
330 	if (p_ptr) {
331 		if (!list_empty(&p_ptr->wait_list))
332 			goto exit;
333 		p_ptr->congested = 1;
334 		p_ptr->waiting_pkts = 1 + ((sz - 1) / l_ptr->max_pkt);
335 		list_add_tail(&p_ptr->wait_list, &l_ptr->waiting_ports);
336 		l_ptr->stats.link_congs++;
337 exit:
338 		tipc_port_unlock(p_ptr);
339 	}
340 	spin_unlock_bh(&tipc_port_list_lock);
341 	return -ELINKCONG;
342 }
343 
344 void tipc_link_wakeup_ports(struct tipc_link *l_ptr, int all)
345 {
346 	struct tipc_port *p_ptr;
347 	struct tipc_port *temp_p_ptr;
348 	int win = l_ptr->queue_limit[0] - l_ptr->out_queue_size;
349 
350 	if (all)
351 		win = 100000;
352 	if (win <= 0)
353 		return;
354 	if (!spin_trylock_bh(&tipc_port_list_lock))
355 		return;
356 	if (link_congested(l_ptr))
357 		goto exit;
358 	list_for_each_entry_safe(p_ptr, temp_p_ptr, &l_ptr->waiting_ports,
359 				 wait_list) {
360 		if (win <= 0)
361 			break;
362 		list_del_init(&p_ptr->wait_list);
363 		spin_lock_bh(p_ptr->lock);
364 		p_ptr->congested = 0;
365 		tipc_port_wakeup(p_ptr);
366 		win -= p_ptr->waiting_pkts;
367 		spin_unlock_bh(p_ptr->lock);
368 	}
369 
370 exit:
371 	spin_unlock_bh(&tipc_port_list_lock);
372 }
373 
374 /**
375  * link_release_outqueue - purge link's outbound message queue
376  * @l_ptr: pointer to link
377  */
378 static void link_release_outqueue(struct tipc_link *l_ptr)
379 {
380 	kfree_skb_list(l_ptr->first_out);
381 	l_ptr->first_out = NULL;
382 	l_ptr->out_queue_size = 0;
383 }
384 
385 /**
386  * tipc_link_reset_fragments - purge link's inbound message fragments queue
387  * @l_ptr: pointer to link
388  */
389 void tipc_link_reset_fragments(struct tipc_link *l_ptr)
390 {
391 	kfree_skb(l_ptr->reasm_head);
392 	l_ptr->reasm_head = NULL;
393 	l_ptr->reasm_tail = NULL;
394 }
395 
396 /**
397  * tipc_link_purge_queues - purge all pkt queues associated with link
398  * @l_ptr: pointer to link
399  */
400 void tipc_link_purge_queues(struct tipc_link *l_ptr)
401 {
402 	kfree_skb_list(l_ptr->oldest_deferred_in);
403 	kfree_skb_list(l_ptr->first_out);
404 	tipc_link_reset_fragments(l_ptr);
405 	kfree_skb(l_ptr->proto_msg_queue);
406 	l_ptr->proto_msg_queue = NULL;
407 }
408 
409 void tipc_link_reset(struct tipc_link *l_ptr)
410 {
411 	u32 prev_state = l_ptr->state;
412 	u32 checkpoint = l_ptr->next_in_no;
413 	int was_active_link = tipc_link_is_active(l_ptr);
414 
415 	msg_set_session(l_ptr->pmsg, ((msg_session(l_ptr->pmsg) + 1) & 0xffff));
416 
417 	/* Link is down, accept any session */
418 	l_ptr->peer_session = INVALID_SESSION;
419 
420 	/* Prepare for max packet size negotiation */
421 	link_init_max_pkt(l_ptr);
422 
423 	l_ptr->state = RESET_UNKNOWN;
424 
425 	if ((prev_state == RESET_UNKNOWN) || (prev_state == RESET_RESET))
426 		return;
427 
428 	tipc_node_link_down(l_ptr->owner, l_ptr);
429 	tipc_bearer_remove_dest(l_ptr->b_ptr, l_ptr->addr);
430 
431 	if (was_active_link && tipc_node_active_links(l_ptr->owner)) {
432 		l_ptr->reset_checkpoint = checkpoint;
433 		l_ptr->exp_msg_count = START_CHANGEOVER;
434 	}
435 
436 	/* Clean up all queues: */
437 	link_release_outqueue(l_ptr);
438 	kfree_skb(l_ptr->proto_msg_queue);
439 	l_ptr->proto_msg_queue = NULL;
440 	kfree_skb_list(l_ptr->oldest_deferred_in);
441 	if (!list_empty(&l_ptr->waiting_ports))
442 		tipc_link_wakeup_ports(l_ptr, 1);
443 
444 	l_ptr->retransm_queue_head = 0;
445 	l_ptr->retransm_queue_size = 0;
446 	l_ptr->last_out = NULL;
447 	l_ptr->first_out = NULL;
448 	l_ptr->next_out = NULL;
449 	l_ptr->unacked_window = 0;
450 	l_ptr->checkpoint = 1;
451 	l_ptr->next_out_no = 1;
452 	l_ptr->deferred_inqueue_sz = 0;
453 	l_ptr->oldest_deferred_in = NULL;
454 	l_ptr->newest_deferred_in = NULL;
455 	l_ptr->fsm_msg_cnt = 0;
456 	l_ptr->stale_count = 0;
457 	link_reset_statistics(l_ptr);
458 }
459 
460 void tipc_link_reset_list(unsigned int bearer_id)
461 {
462 	struct tipc_link *l_ptr;
463 	struct tipc_node *n_ptr;
464 
465 	rcu_read_lock();
466 	list_for_each_entry_rcu(n_ptr, &tipc_node_list, list) {
467 		spin_lock_bh(&n_ptr->lock);
468 		l_ptr = n_ptr->links[bearer_id];
469 		if (l_ptr)
470 			tipc_link_reset(l_ptr);
471 		spin_unlock_bh(&n_ptr->lock);
472 	}
473 	rcu_read_unlock();
474 }
475 
476 static void link_activate(struct tipc_link *l_ptr)
477 {
478 	l_ptr->next_in_no = l_ptr->stats.recv_info = 1;
479 	tipc_node_link_up(l_ptr->owner, l_ptr);
480 	tipc_bearer_add_dest(l_ptr->b_ptr, l_ptr->addr);
481 }
482 
483 /**
484  * link_state_event - link finite state machine
485  * @l_ptr: pointer to link
486  * @event: state machine event to process
487  */
488 static void link_state_event(struct tipc_link *l_ptr, unsigned int event)
489 {
490 	struct tipc_link *other;
491 	u32 cont_intv = l_ptr->continuity_interval;
492 
493 	if (l_ptr->flags & LINK_STOPPED)
494 		return;
495 
496 	if (!(l_ptr->flags & LINK_STARTED) && (event != STARTING_EVT))
497 		return;		/* Not yet. */
498 
499 	/* Check whether changeover is going on */
500 	if (l_ptr->exp_msg_count) {
501 		if (event == TIMEOUT_EVT)
502 			link_set_timer(l_ptr, cont_intv);
503 		return;
504 	}
505 
506 	switch (l_ptr->state) {
507 	case WORKING_WORKING:
508 		switch (event) {
509 		case TRAFFIC_MSG_EVT:
510 		case ACTIVATE_MSG:
511 			break;
512 		case TIMEOUT_EVT:
513 			if (l_ptr->next_in_no != l_ptr->checkpoint) {
514 				l_ptr->checkpoint = l_ptr->next_in_no;
515 				if (tipc_bclink_acks_missing(l_ptr->owner)) {
516 					tipc_link_proto_xmit(l_ptr, STATE_MSG,
517 							     0, 0, 0, 0, 0);
518 					l_ptr->fsm_msg_cnt++;
519 				} else if (l_ptr->max_pkt < l_ptr->max_pkt_target) {
520 					tipc_link_proto_xmit(l_ptr, STATE_MSG,
521 							     1, 0, 0, 0, 0);
522 					l_ptr->fsm_msg_cnt++;
523 				}
524 				link_set_timer(l_ptr, cont_intv);
525 				break;
526 			}
527 			l_ptr->state = WORKING_UNKNOWN;
528 			l_ptr->fsm_msg_cnt = 0;
529 			tipc_link_proto_xmit(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
530 			l_ptr->fsm_msg_cnt++;
531 			link_set_timer(l_ptr, cont_intv / 4);
532 			break;
533 		case RESET_MSG:
534 			pr_info("%s<%s>, requested by peer\n", link_rst_msg,
535 				l_ptr->name);
536 			tipc_link_reset(l_ptr);
537 			l_ptr->state = RESET_RESET;
538 			l_ptr->fsm_msg_cnt = 0;
539 			tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
540 					     0, 0, 0, 0, 0);
541 			l_ptr->fsm_msg_cnt++;
542 			link_set_timer(l_ptr, cont_intv);
543 			break;
544 		default:
545 			pr_err("%s%u in WW state\n", link_unk_evt, event);
546 		}
547 		break;
548 	case WORKING_UNKNOWN:
549 		switch (event) {
550 		case TRAFFIC_MSG_EVT:
551 		case ACTIVATE_MSG:
552 			l_ptr->state = WORKING_WORKING;
553 			l_ptr->fsm_msg_cnt = 0;
554 			link_set_timer(l_ptr, cont_intv);
555 			break;
556 		case RESET_MSG:
557 			pr_info("%s<%s>, requested by peer while probing\n",
558 				link_rst_msg, l_ptr->name);
559 			tipc_link_reset(l_ptr);
560 			l_ptr->state = RESET_RESET;
561 			l_ptr->fsm_msg_cnt = 0;
562 			tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
563 					     0, 0, 0, 0, 0);
564 			l_ptr->fsm_msg_cnt++;
565 			link_set_timer(l_ptr, cont_intv);
566 			break;
567 		case TIMEOUT_EVT:
568 			if (l_ptr->next_in_no != l_ptr->checkpoint) {
569 				l_ptr->state = WORKING_WORKING;
570 				l_ptr->fsm_msg_cnt = 0;
571 				l_ptr->checkpoint = l_ptr->next_in_no;
572 				if (tipc_bclink_acks_missing(l_ptr->owner)) {
573 					tipc_link_proto_xmit(l_ptr, STATE_MSG,
574 							     0, 0, 0, 0, 0);
575 					l_ptr->fsm_msg_cnt++;
576 				}
577 				link_set_timer(l_ptr, cont_intv);
578 			} else if (l_ptr->fsm_msg_cnt < l_ptr->abort_limit) {
579 				tipc_link_proto_xmit(l_ptr, STATE_MSG,
580 						     1, 0, 0, 0, 0);
581 				l_ptr->fsm_msg_cnt++;
582 				link_set_timer(l_ptr, cont_intv / 4);
583 			} else {	/* Link has failed */
584 				pr_warn("%s<%s>, peer not responding\n",
585 					link_rst_msg, l_ptr->name);
586 				tipc_link_reset(l_ptr);
587 				l_ptr->state = RESET_UNKNOWN;
588 				l_ptr->fsm_msg_cnt = 0;
589 				tipc_link_proto_xmit(l_ptr, RESET_MSG,
590 						     0, 0, 0, 0, 0);
591 				l_ptr->fsm_msg_cnt++;
592 				link_set_timer(l_ptr, cont_intv);
593 			}
594 			break;
595 		default:
596 			pr_err("%s%u in WU state\n", link_unk_evt, event);
597 		}
598 		break;
599 	case RESET_UNKNOWN:
600 		switch (event) {
601 		case TRAFFIC_MSG_EVT:
602 			break;
603 		case ACTIVATE_MSG:
604 			other = l_ptr->owner->active_links[0];
605 			if (other && link_working_unknown(other))
606 				break;
607 			l_ptr->state = WORKING_WORKING;
608 			l_ptr->fsm_msg_cnt = 0;
609 			link_activate(l_ptr);
610 			tipc_link_proto_xmit(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
611 			l_ptr->fsm_msg_cnt++;
612 			if (l_ptr->owner->working_links == 1)
613 				tipc_link_sync_xmit(l_ptr);
614 			link_set_timer(l_ptr, cont_intv);
615 			break;
616 		case RESET_MSG:
617 			l_ptr->state = RESET_RESET;
618 			l_ptr->fsm_msg_cnt = 0;
619 			tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
620 					     1, 0, 0, 0, 0);
621 			l_ptr->fsm_msg_cnt++;
622 			link_set_timer(l_ptr, cont_intv);
623 			break;
624 		case STARTING_EVT:
625 			l_ptr->flags |= LINK_STARTED;
626 			/* fall through */
627 		case TIMEOUT_EVT:
628 			tipc_link_proto_xmit(l_ptr, RESET_MSG, 0, 0, 0, 0, 0);
629 			l_ptr->fsm_msg_cnt++;
630 			link_set_timer(l_ptr, cont_intv);
631 			break;
632 		default:
633 			pr_err("%s%u in RU state\n", link_unk_evt, event);
634 		}
635 		break;
636 	case RESET_RESET:
637 		switch (event) {
638 		case TRAFFIC_MSG_EVT:
639 		case ACTIVATE_MSG:
640 			other = l_ptr->owner->active_links[0];
641 			if (other && link_working_unknown(other))
642 				break;
643 			l_ptr->state = WORKING_WORKING;
644 			l_ptr->fsm_msg_cnt = 0;
645 			link_activate(l_ptr);
646 			tipc_link_proto_xmit(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
647 			l_ptr->fsm_msg_cnt++;
648 			if (l_ptr->owner->working_links == 1)
649 				tipc_link_sync_xmit(l_ptr);
650 			link_set_timer(l_ptr, cont_intv);
651 			break;
652 		case RESET_MSG:
653 			break;
654 		case TIMEOUT_EVT:
655 			tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
656 					     0, 0, 0, 0, 0);
657 			l_ptr->fsm_msg_cnt++;
658 			link_set_timer(l_ptr, cont_intv);
659 			break;
660 		default:
661 			pr_err("%s%u in RR state\n", link_unk_evt, event);
662 		}
663 		break;
664 	default:
665 		pr_err("Unknown link state %u/%u\n", l_ptr->state, event);
666 	}
667 }
668 
669 /*
670  * link_bundle_buf(): Append contents of a buffer to
671  * the tail of an existing one.
672  */
673 static int link_bundle_buf(struct tipc_link *l_ptr, struct sk_buff *bundler,
674 			   struct sk_buff *buf)
675 {
676 	struct tipc_msg *bundler_msg = buf_msg(bundler);
677 	struct tipc_msg *msg = buf_msg(buf);
678 	u32 size = msg_size(msg);
679 	u32 bundle_size = msg_size(bundler_msg);
680 	u32 to_pos = align(bundle_size);
681 	u32 pad = to_pos - bundle_size;
682 
683 	if (msg_user(bundler_msg) != MSG_BUNDLER)
684 		return 0;
685 	if (msg_type(bundler_msg) != OPEN_MSG)
686 		return 0;
687 	if (skb_tailroom(bundler) < (pad + size))
688 		return 0;
689 	if (l_ptr->max_pkt < (to_pos + size))
690 		return 0;
691 
692 	skb_put(bundler, pad + size);
693 	skb_copy_to_linear_data_offset(bundler, to_pos, buf->data, size);
694 	msg_set_size(bundler_msg, to_pos + size);
695 	msg_set_msgcnt(bundler_msg, msg_msgcnt(bundler_msg) + 1);
696 	kfree_skb(buf);
697 	l_ptr->stats.sent_bundled++;
698 	return 1;
699 }
700 
701 static void link_add_to_outqueue(struct tipc_link *l_ptr,
702 				 struct sk_buff *buf,
703 				 struct tipc_msg *msg)
704 {
705 	u32 ack = mod(l_ptr->next_in_no - 1);
706 	u32 seqno = mod(l_ptr->next_out_no++);
707 
708 	msg_set_word(msg, 2, ((ack << 16) | seqno));
709 	msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
710 	buf->next = NULL;
711 	if (l_ptr->first_out) {
712 		l_ptr->last_out->next = buf;
713 		l_ptr->last_out = buf;
714 	} else
715 		l_ptr->first_out = l_ptr->last_out = buf;
716 
717 	l_ptr->out_queue_size++;
718 	if (l_ptr->out_queue_size > l_ptr->stats.max_queue_sz)
719 		l_ptr->stats.max_queue_sz = l_ptr->out_queue_size;
720 }
721 
722 static void link_add_chain_to_outqueue(struct tipc_link *l_ptr,
723 				       struct sk_buff *buf_chain,
724 				       u32 long_msgno)
725 {
726 	struct sk_buff *buf;
727 	struct tipc_msg *msg;
728 
729 	if (!l_ptr->next_out)
730 		l_ptr->next_out = buf_chain;
731 	while (buf_chain) {
732 		buf = buf_chain;
733 		buf_chain = buf_chain->next;
734 
735 		msg = buf_msg(buf);
736 		msg_set_long_msgno(msg, long_msgno);
737 		link_add_to_outqueue(l_ptr, buf, msg);
738 	}
739 }
740 
741 /*
742  * tipc_link_xmit() is the 'full path' for messages, called from
743  * inside TIPC when the 'fast path' in tipc_send_xmit
744  * has failed, and from link_send()
745  */
746 int __tipc_link_xmit(struct tipc_link *l_ptr, struct sk_buff *buf)
747 {
748 	struct tipc_msg *msg = buf_msg(buf);
749 	u32 size = msg_size(msg);
750 	u32 dsz = msg_data_sz(msg);
751 	u32 queue_size = l_ptr->out_queue_size;
752 	u32 imp = tipc_msg_tot_importance(msg);
753 	u32 queue_limit = l_ptr->queue_limit[imp];
754 	u32 max_packet = l_ptr->max_pkt;
755 
756 	/* Match msg importance against queue limits: */
757 	if (unlikely(queue_size >= queue_limit)) {
758 		if (imp <= TIPC_CRITICAL_IMPORTANCE) {
759 			link_schedule_port(l_ptr, msg_origport(msg), size);
760 			kfree_skb(buf);
761 			return -ELINKCONG;
762 		}
763 		kfree_skb(buf);
764 		if (imp > CONN_MANAGER) {
765 			pr_warn("%s<%s>, send queue full", link_rst_msg,
766 				l_ptr->name);
767 			tipc_link_reset(l_ptr);
768 		}
769 		return dsz;
770 	}
771 
772 	/* Fragmentation needed ? */
773 	if (size > max_packet)
774 		return tipc_link_frag_xmit(l_ptr, buf);
775 
776 	/* Packet can be queued or sent. */
777 	if (likely(!link_congested(l_ptr))) {
778 		link_add_to_outqueue(l_ptr, buf, msg);
779 
780 		tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr);
781 		l_ptr->unacked_window = 0;
782 		return dsz;
783 	}
784 	/* Congestion: can message be bundled ? */
785 	if ((msg_user(msg) != CHANGEOVER_PROTOCOL) &&
786 	    (msg_user(msg) != MSG_FRAGMENTER)) {
787 
788 		/* Try adding message to an existing bundle */
789 		if (l_ptr->next_out &&
790 		    link_bundle_buf(l_ptr, l_ptr->last_out, buf))
791 			return dsz;
792 
793 		/* Try creating a new bundle */
794 		if (size <= max_packet * 2 / 3) {
795 			struct sk_buff *bundler = tipc_buf_acquire(max_packet);
796 			struct tipc_msg bundler_hdr;
797 
798 			if (bundler) {
799 				tipc_msg_init(&bundler_hdr, MSG_BUNDLER, OPEN_MSG,
800 					 INT_H_SIZE, l_ptr->addr);
801 				skb_copy_to_linear_data(bundler, &bundler_hdr,
802 							INT_H_SIZE);
803 				skb_trim(bundler, INT_H_SIZE);
804 				link_bundle_buf(l_ptr, bundler, buf);
805 				buf = bundler;
806 				msg = buf_msg(buf);
807 				l_ptr->stats.sent_bundles++;
808 			}
809 		}
810 	}
811 	if (!l_ptr->next_out)
812 		l_ptr->next_out = buf;
813 	link_add_to_outqueue(l_ptr, buf, msg);
814 	return dsz;
815 }
816 
817 /*
818  * tipc_link_xmit(): same as __tipc_link_xmit(), but the link to use
819  * has not been selected yet, and the the owner node is not locked
820  * Called by TIPC internal users, e.g. the name distributor
821  */
822 int tipc_link_xmit(struct sk_buff *buf, u32 dest, u32 selector)
823 {
824 	struct tipc_link *l_ptr;
825 	struct tipc_node *n_ptr;
826 	int res = -ELINKCONG;
827 
828 	read_lock_bh(&tipc_net_lock);
829 	n_ptr = tipc_node_find(dest);
830 	if (n_ptr) {
831 		tipc_node_lock(n_ptr);
832 		l_ptr = n_ptr->active_links[selector & 1];
833 		if (l_ptr)
834 			res = __tipc_link_xmit(l_ptr, buf);
835 		else
836 			kfree_skb(buf);
837 		tipc_node_unlock(n_ptr);
838 	} else {
839 		kfree_skb(buf);
840 	}
841 	read_unlock_bh(&tipc_net_lock);
842 	return res;
843 }
844 
845 /*
846  * tipc_link_sync_xmit - synchronize broadcast link endpoints.
847  *
848  * Give a newly added peer node the sequence number where it should
849  * start receiving and acking broadcast packets.
850  *
851  * Called with node locked
852  */
853 static void tipc_link_sync_xmit(struct tipc_link *l)
854 {
855 	struct sk_buff *buf;
856 	struct tipc_msg *msg;
857 
858 	buf = tipc_buf_acquire(INT_H_SIZE);
859 	if (!buf)
860 		return;
861 
862 	msg = buf_msg(buf);
863 	tipc_msg_init(msg, BCAST_PROTOCOL, STATE_MSG, INT_H_SIZE, l->addr);
864 	msg_set_last_bcast(msg, l->owner->bclink.acked);
865 	link_add_chain_to_outqueue(l, buf, 0);
866 	tipc_link_push_queue(l);
867 }
868 
869 /*
870  * tipc_link_sync_rcv - synchronize broadcast link endpoints.
871  * Receive the sequence number where we should start receiving and
872  * acking broadcast packets from a newly added peer node, and open
873  * up for reception of such packets.
874  *
875  * Called with node locked
876  */
877 static void tipc_link_sync_rcv(struct tipc_node *n, struct sk_buff *buf)
878 {
879 	struct tipc_msg *msg = buf_msg(buf);
880 
881 	n->bclink.last_sent = n->bclink.last_in = msg_last_bcast(msg);
882 	n->bclink.recv_permitted = true;
883 	kfree_skb(buf);
884 }
885 
886 /*
887  * tipc_link_names_xmit - send name table entries to new neighbor
888  *
889  * Send routine for bulk delivery of name table messages when contact
890  * with a new neighbor occurs. No link congestion checking is performed
891  * because name table messages *must* be delivered. The messages must be
892  * small enough not to require fragmentation.
893  * Called without any locks held.
894  */
895 void tipc_link_names_xmit(struct list_head *message_list, u32 dest)
896 {
897 	struct tipc_node *n_ptr;
898 	struct tipc_link *l_ptr;
899 	struct sk_buff *buf;
900 	struct sk_buff *temp_buf;
901 
902 	if (list_empty(message_list))
903 		return;
904 
905 	read_lock_bh(&tipc_net_lock);
906 	n_ptr = tipc_node_find(dest);
907 	if (n_ptr) {
908 		tipc_node_lock(n_ptr);
909 		l_ptr = n_ptr->active_links[0];
910 		if (l_ptr) {
911 			/* convert circular list to linear list */
912 			((struct sk_buff *)message_list->prev)->next = NULL;
913 			link_add_chain_to_outqueue(l_ptr,
914 				(struct sk_buff *)message_list->next, 0);
915 			tipc_link_push_queue(l_ptr);
916 			INIT_LIST_HEAD(message_list);
917 		}
918 		tipc_node_unlock(n_ptr);
919 	}
920 	read_unlock_bh(&tipc_net_lock);
921 
922 	/* discard the messages if they couldn't be sent */
923 	list_for_each_safe(buf, temp_buf, ((struct sk_buff *)message_list)) {
924 		list_del((struct list_head *)buf);
925 		kfree_skb(buf);
926 	}
927 }
928 
929 /*
930  * tipc_link_xmit_fast: Entry for data messages where the
931  * destination link is known and the header is complete,
932  * inclusive total message length. Very time critical.
933  * Link is locked. Returns user data length.
934  */
935 static int tipc_link_xmit_fast(struct tipc_link *l_ptr, struct sk_buff *buf,
936 			       u32 *used_max_pkt)
937 {
938 	struct tipc_msg *msg = buf_msg(buf);
939 	int res = msg_data_sz(msg);
940 
941 	if (likely(!link_congested(l_ptr))) {
942 		if (likely(msg_size(msg) <= l_ptr->max_pkt)) {
943 			link_add_to_outqueue(l_ptr, buf, msg);
944 			tipc_bearer_send(l_ptr->b_ptr, buf,
945 					 &l_ptr->media_addr);
946 			l_ptr->unacked_window = 0;
947 			return res;
948 		}
949 		else
950 			*used_max_pkt = l_ptr->max_pkt;
951 	}
952 	return __tipc_link_xmit(l_ptr, buf);  /* All other cases */
953 }
954 
955 /*
956  * tipc_link_iovec_xmit_fast: Entry for messages where the
957  * destination processor is known and the header is complete,
958  * except for total message length.
959  * Returns user data length or errno.
960  */
961 int tipc_link_iovec_xmit_fast(struct tipc_port *sender,
962 			      struct iovec const *msg_sect,
963 			      unsigned int len, u32 destaddr)
964 {
965 	struct tipc_msg *hdr = &sender->phdr;
966 	struct tipc_link *l_ptr;
967 	struct sk_buff *buf;
968 	struct tipc_node *node;
969 	int res;
970 	u32 selector = msg_origport(hdr) & 1;
971 
972 again:
973 	/*
974 	 * Try building message using port's max_pkt hint.
975 	 * (Must not hold any locks while building message.)
976 	 */
977 	res = tipc_msg_build(hdr, msg_sect, len, sender->max_pkt, &buf);
978 	/* Exit if build request was invalid */
979 	if (unlikely(res < 0))
980 		return res;
981 
982 	read_lock_bh(&tipc_net_lock);
983 	node = tipc_node_find(destaddr);
984 	if (likely(node)) {
985 		tipc_node_lock(node);
986 		l_ptr = node->active_links[selector];
987 		if (likely(l_ptr)) {
988 			if (likely(buf)) {
989 				res = tipc_link_xmit_fast(l_ptr, buf,
990 							  &sender->max_pkt);
991 exit:
992 				tipc_node_unlock(node);
993 				read_unlock_bh(&tipc_net_lock);
994 				return res;
995 			}
996 
997 			/* Exit if link (or bearer) is congested */
998 			if (link_congested(l_ptr)) {
999 				res = link_schedule_port(l_ptr,
1000 							 sender->ref, res);
1001 				goto exit;
1002 			}
1003 
1004 			/*
1005 			 * Message size exceeds max_pkt hint; update hint,
1006 			 * then re-try fast path or fragment the message
1007 			 */
1008 			sender->max_pkt = l_ptr->max_pkt;
1009 			tipc_node_unlock(node);
1010 			read_unlock_bh(&tipc_net_lock);
1011 
1012 
1013 			if ((msg_hdr_sz(hdr) + res) <= sender->max_pkt)
1014 				goto again;
1015 
1016 			return tipc_link_iovec_long_xmit(sender, msg_sect,
1017 							 len, destaddr);
1018 		}
1019 		tipc_node_unlock(node);
1020 	}
1021 	read_unlock_bh(&tipc_net_lock);
1022 
1023 	/* Couldn't find a link to the destination node */
1024 	kfree_skb(buf);
1025 	tipc_port_iovec_reject(sender, hdr, msg_sect, len, TIPC_ERR_NO_NODE);
1026 	return -ENETUNREACH;
1027 }
1028 
1029 /*
1030  * tipc_link_iovec_long_xmit(): Entry for long messages where the
1031  * destination node is known and the header is complete,
1032  * inclusive total message length.
1033  * Link and bearer congestion status have been checked to be ok,
1034  * and are ignored if they change.
1035  *
1036  * Note that fragments do not use the full link MTU so that they won't have
1037  * to undergo refragmentation if link changeover causes them to be sent
1038  * over another link with an additional tunnel header added as prefix.
1039  * (Refragmentation will still occur if the other link has a smaller MTU.)
1040  *
1041  * Returns user data length or errno.
1042  */
1043 static int tipc_link_iovec_long_xmit(struct tipc_port *sender,
1044 				     struct iovec const *msg_sect,
1045 				     unsigned int len, u32 destaddr)
1046 {
1047 	struct tipc_link *l_ptr;
1048 	struct tipc_node *node;
1049 	struct tipc_msg *hdr = &sender->phdr;
1050 	u32 dsz = len;
1051 	u32 max_pkt, fragm_sz, rest;
1052 	struct tipc_msg fragm_hdr;
1053 	struct sk_buff *buf, *buf_chain, *prev;
1054 	u32 fragm_crs, fragm_rest, hsz, sect_rest;
1055 	const unchar __user *sect_crs;
1056 	int curr_sect;
1057 	u32 fragm_no;
1058 	int res = 0;
1059 
1060 again:
1061 	fragm_no = 1;
1062 	max_pkt = sender->max_pkt - INT_H_SIZE;
1063 		/* leave room for tunnel header in case of link changeover */
1064 	fragm_sz = max_pkt - INT_H_SIZE;
1065 		/* leave room for fragmentation header in each fragment */
1066 	rest = dsz;
1067 	fragm_crs = 0;
1068 	fragm_rest = 0;
1069 	sect_rest = 0;
1070 	sect_crs = NULL;
1071 	curr_sect = -1;
1072 
1073 	/* Prepare reusable fragment header */
1074 	tipc_msg_init(&fragm_hdr, MSG_FRAGMENTER, FIRST_FRAGMENT,
1075 		 INT_H_SIZE, msg_destnode(hdr));
1076 	msg_set_size(&fragm_hdr, max_pkt);
1077 	msg_set_fragm_no(&fragm_hdr, 1);
1078 
1079 	/* Prepare header of first fragment */
1080 	buf_chain = buf = tipc_buf_acquire(max_pkt);
1081 	if (!buf)
1082 		return -ENOMEM;
1083 	buf->next = NULL;
1084 	skb_copy_to_linear_data(buf, &fragm_hdr, INT_H_SIZE);
1085 	hsz = msg_hdr_sz(hdr);
1086 	skb_copy_to_linear_data_offset(buf, INT_H_SIZE, hdr, hsz);
1087 
1088 	/* Chop up message */
1089 	fragm_crs = INT_H_SIZE + hsz;
1090 	fragm_rest = fragm_sz - hsz;
1091 
1092 	do {		/* For all sections */
1093 		u32 sz;
1094 
1095 		if (!sect_rest) {
1096 			sect_rest = msg_sect[++curr_sect].iov_len;
1097 			sect_crs = msg_sect[curr_sect].iov_base;
1098 		}
1099 
1100 		if (sect_rest < fragm_rest)
1101 			sz = sect_rest;
1102 		else
1103 			sz = fragm_rest;
1104 
1105 		if (copy_from_user(buf->data + fragm_crs, sect_crs, sz)) {
1106 			res = -EFAULT;
1107 error:
1108 			kfree_skb_list(buf_chain);
1109 			return res;
1110 		}
1111 		sect_crs += sz;
1112 		sect_rest -= sz;
1113 		fragm_crs += sz;
1114 		fragm_rest -= sz;
1115 		rest -= sz;
1116 
1117 		if (!fragm_rest && rest) {
1118 
1119 			/* Initiate new fragment: */
1120 			if (rest <= fragm_sz) {
1121 				fragm_sz = rest;
1122 				msg_set_type(&fragm_hdr, LAST_FRAGMENT);
1123 			} else {
1124 				msg_set_type(&fragm_hdr, FRAGMENT);
1125 			}
1126 			msg_set_size(&fragm_hdr, fragm_sz + INT_H_SIZE);
1127 			msg_set_fragm_no(&fragm_hdr, ++fragm_no);
1128 			prev = buf;
1129 			buf = tipc_buf_acquire(fragm_sz + INT_H_SIZE);
1130 			if (!buf) {
1131 				res = -ENOMEM;
1132 				goto error;
1133 			}
1134 
1135 			buf->next = NULL;
1136 			prev->next = buf;
1137 			skb_copy_to_linear_data(buf, &fragm_hdr, INT_H_SIZE);
1138 			fragm_crs = INT_H_SIZE;
1139 			fragm_rest = fragm_sz;
1140 		}
1141 	} while (rest > 0);
1142 
1143 	/*
1144 	 * Now we have a buffer chain. Select a link and check
1145 	 * that packet size is still OK
1146 	 */
1147 	node = tipc_node_find(destaddr);
1148 	if (likely(node)) {
1149 		tipc_node_lock(node);
1150 		l_ptr = node->active_links[sender->ref & 1];
1151 		if (!l_ptr) {
1152 			tipc_node_unlock(node);
1153 			goto reject;
1154 		}
1155 		if (l_ptr->max_pkt < max_pkt) {
1156 			sender->max_pkt = l_ptr->max_pkt;
1157 			tipc_node_unlock(node);
1158 			kfree_skb_list(buf_chain);
1159 			goto again;
1160 		}
1161 	} else {
1162 reject:
1163 		kfree_skb_list(buf_chain);
1164 		tipc_port_iovec_reject(sender, hdr, msg_sect, len,
1165 				       TIPC_ERR_NO_NODE);
1166 		return -ENETUNREACH;
1167 	}
1168 
1169 	/* Append chain of fragments to send queue & send them */
1170 	l_ptr->long_msg_seq_no++;
1171 	link_add_chain_to_outqueue(l_ptr, buf_chain, l_ptr->long_msg_seq_no);
1172 	l_ptr->stats.sent_fragments += fragm_no;
1173 	l_ptr->stats.sent_fragmented++;
1174 	tipc_link_push_queue(l_ptr);
1175 	tipc_node_unlock(node);
1176 	return dsz;
1177 }
1178 
1179 /*
1180  * tipc_link_push_packet: Push one unsent packet to the media
1181  */
1182 static u32 tipc_link_push_packet(struct tipc_link *l_ptr)
1183 {
1184 	struct sk_buff *buf = l_ptr->first_out;
1185 	u32 r_q_size = l_ptr->retransm_queue_size;
1186 	u32 r_q_head = l_ptr->retransm_queue_head;
1187 
1188 	/* Step to position where retransmission failed, if any,    */
1189 	/* consider that buffers may have been released in meantime */
1190 	if (r_q_size && buf) {
1191 		u32 last = lesser(mod(r_q_head + r_q_size),
1192 				  link_last_sent(l_ptr));
1193 		u32 first = buf_seqno(buf);
1194 
1195 		while (buf && less(first, r_q_head)) {
1196 			first = mod(first + 1);
1197 			buf = buf->next;
1198 		}
1199 		l_ptr->retransm_queue_head = r_q_head = first;
1200 		l_ptr->retransm_queue_size = r_q_size = mod(last - first);
1201 	}
1202 
1203 	/* Continue retransmission now, if there is anything: */
1204 	if (r_q_size && buf) {
1205 		msg_set_ack(buf_msg(buf), mod(l_ptr->next_in_no - 1));
1206 		msg_set_bcast_ack(buf_msg(buf), l_ptr->owner->bclink.last_in);
1207 		tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr);
1208 		l_ptr->retransm_queue_head = mod(++r_q_head);
1209 		l_ptr->retransm_queue_size = --r_q_size;
1210 		l_ptr->stats.retransmitted++;
1211 		return 0;
1212 	}
1213 
1214 	/* Send deferred protocol message, if any: */
1215 	buf = l_ptr->proto_msg_queue;
1216 	if (buf) {
1217 		msg_set_ack(buf_msg(buf), mod(l_ptr->next_in_no - 1));
1218 		msg_set_bcast_ack(buf_msg(buf), l_ptr->owner->bclink.last_in);
1219 		tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr);
1220 		l_ptr->unacked_window = 0;
1221 		kfree_skb(buf);
1222 		l_ptr->proto_msg_queue = NULL;
1223 		return 0;
1224 	}
1225 
1226 	/* Send one deferred data message, if send window not full: */
1227 	buf = l_ptr->next_out;
1228 	if (buf) {
1229 		struct tipc_msg *msg = buf_msg(buf);
1230 		u32 next = msg_seqno(msg);
1231 		u32 first = buf_seqno(l_ptr->first_out);
1232 
1233 		if (mod(next - first) < l_ptr->queue_limit[0]) {
1234 			msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1235 			msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1236 			tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr);
1237 			if (msg_user(msg) == MSG_BUNDLER)
1238 				msg_set_type(msg, CLOSED_MSG);
1239 			l_ptr->next_out = buf->next;
1240 			return 0;
1241 		}
1242 	}
1243 	return 1;
1244 }
1245 
1246 /*
1247  * push_queue(): push out the unsent messages of a link where
1248  *               congestion has abated. Node is locked
1249  */
1250 void tipc_link_push_queue(struct tipc_link *l_ptr)
1251 {
1252 	u32 res;
1253 
1254 	do {
1255 		res = tipc_link_push_packet(l_ptr);
1256 	} while (!res);
1257 }
1258 
1259 static void link_reset_all(unsigned long addr)
1260 {
1261 	struct tipc_node *n_ptr;
1262 	char addr_string[16];
1263 	u32 i;
1264 
1265 	read_lock_bh(&tipc_net_lock);
1266 	n_ptr = tipc_node_find((u32)addr);
1267 	if (!n_ptr) {
1268 		read_unlock_bh(&tipc_net_lock);
1269 		return;	/* node no longer exists */
1270 	}
1271 
1272 	tipc_node_lock(n_ptr);
1273 
1274 	pr_warn("Resetting all links to %s\n",
1275 		tipc_addr_string_fill(addr_string, n_ptr->addr));
1276 
1277 	for (i = 0; i < MAX_BEARERS; i++) {
1278 		if (n_ptr->links[i]) {
1279 			link_print(n_ptr->links[i], "Resetting link\n");
1280 			tipc_link_reset(n_ptr->links[i]);
1281 		}
1282 	}
1283 
1284 	tipc_node_unlock(n_ptr);
1285 	read_unlock_bh(&tipc_net_lock);
1286 }
1287 
1288 static void link_retransmit_failure(struct tipc_link *l_ptr,
1289 				    struct sk_buff *buf)
1290 {
1291 	struct tipc_msg *msg = buf_msg(buf);
1292 
1293 	pr_warn("Retransmission failure on link <%s>\n", l_ptr->name);
1294 
1295 	if (l_ptr->addr) {
1296 		/* Handle failure on standard link */
1297 		link_print(l_ptr, "Resetting link\n");
1298 		tipc_link_reset(l_ptr);
1299 
1300 	} else {
1301 		/* Handle failure on broadcast link */
1302 		struct tipc_node *n_ptr;
1303 		char addr_string[16];
1304 
1305 		pr_info("Msg seq number: %u,  ", msg_seqno(msg));
1306 		pr_cont("Outstanding acks: %lu\n",
1307 			(unsigned long) TIPC_SKB_CB(buf)->handle);
1308 
1309 		n_ptr = tipc_bclink_retransmit_to();
1310 		tipc_node_lock(n_ptr);
1311 
1312 		tipc_addr_string_fill(addr_string, n_ptr->addr);
1313 		pr_info("Broadcast link info for %s\n", addr_string);
1314 		pr_info("Reception permitted: %d,  Acked: %u\n",
1315 			n_ptr->bclink.recv_permitted,
1316 			n_ptr->bclink.acked);
1317 		pr_info("Last in: %u,  Oos state: %u,  Last sent: %u\n",
1318 			n_ptr->bclink.last_in,
1319 			n_ptr->bclink.oos_state,
1320 			n_ptr->bclink.last_sent);
1321 
1322 		tipc_k_signal((Handler)link_reset_all, (unsigned long)n_ptr->addr);
1323 
1324 		tipc_node_unlock(n_ptr);
1325 
1326 		l_ptr->stale_count = 0;
1327 	}
1328 }
1329 
1330 void tipc_link_retransmit(struct tipc_link *l_ptr, struct sk_buff *buf,
1331 			  u32 retransmits)
1332 {
1333 	struct tipc_msg *msg;
1334 
1335 	if (!buf)
1336 		return;
1337 
1338 	msg = buf_msg(buf);
1339 
1340 	/* Detect repeated retransmit failures */
1341 	if (l_ptr->last_retransmitted == msg_seqno(msg)) {
1342 		if (++l_ptr->stale_count > 100) {
1343 			link_retransmit_failure(l_ptr, buf);
1344 			return;
1345 		}
1346 	} else {
1347 		l_ptr->last_retransmitted = msg_seqno(msg);
1348 		l_ptr->stale_count = 1;
1349 	}
1350 
1351 	while (retransmits && (buf != l_ptr->next_out) && buf) {
1352 		msg = buf_msg(buf);
1353 		msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1354 		msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1355 		tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr);
1356 		buf = buf->next;
1357 		retransmits--;
1358 		l_ptr->stats.retransmitted++;
1359 	}
1360 
1361 	l_ptr->retransm_queue_head = l_ptr->retransm_queue_size = 0;
1362 }
1363 
1364 /**
1365  * link_insert_deferred_queue - insert deferred messages back into receive chain
1366  */
1367 static struct sk_buff *link_insert_deferred_queue(struct tipc_link *l_ptr,
1368 						  struct sk_buff *buf)
1369 {
1370 	u32 seq_no;
1371 
1372 	if (l_ptr->oldest_deferred_in == NULL)
1373 		return buf;
1374 
1375 	seq_no = buf_seqno(l_ptr->oldest_deferred_in);
1376 	if (seq_no == mod(l_ptr->next_in_no)) {
1377 		l_ptr->newest_deferred_in->next = buf;
1378 		buf = l_ptr->oldest_deferred_in;
1379 		l_ptr->oldest_deferred_in = NULL;
1380 		l_ptr->deferred_inqueue_sz = 0;
1381 	}
1382 	return buf;
1383 }
1384 
1385 /**
1386  * link_recv_buf_validate - validate basic format of received message
1387  *
1388  * This routine ensures a TIPC message has an acceptable header, and at least
1389  * as much data as the header indicates it should.  The routine also ensures
1390  * that the entire message header is stored in the main fragment of the message
1391  * buffer, to simplify future access to message header fields.
1392  *
1393  * Note: Having extra info present in the message header or data areas is OK.
1394  * TIPC will ignore the excess, under the assumption that it is optional info
1395  * introduced by a later release of the protocol.
1396  */
1397 static int link_recv_buf_validate(struct sk_buff *buf)
1398 {
1399 	static u32 min_data_hdr_size[8] = {
1400 		SHORT_H_SIZE, MCAST_H_SIZE, NAMED_H_SIZE, BASIC_H_SIZE,
1401 		MAX_H_SIZE, MAX_H_SIZE, MAX_H_SIZE, MAX_H_SIZE
1402 		};
1403 
1404 	struct tipc_msg *msg;
1405 	u32 tipc_hdr[2];
1406 	u32 size;
1407 	u32 hdr_size;
1408 	u32 min_hdr_size;
1409 
1410 	/* If this packet comes from the defer queue, the skb has already
1411 	 * been validated
1412 	 */
1413 	if (unlikely(TIPC_SKB_CB(buf)->deferred))
1414 		return 1;
1415 
1416 	if (unlikely(buf->len < MIN_H_SIZE))
1417 		return 0;
1418 
1419 	msg = skb_header_pointer(buf, 0, sizeof(tipc_hdr), tipc_hdr);
1420 	if (msg == NULL)
1421 		return 0;
1422 
1423 	if (unlikely(msg_version(msg) != TIPC_VERSION))
1424 		return 0;
1425 
1426 	size = msg_size(msg);
1427 	hdr_size = msg_hdr_sz(msg);
1428 	min_hdr_size = msg_isdata(msg) ?
1429 		min_data_hdr_size[msg_type(msg)] : INT_H_SIZE;
1430 
1431 	if (unlikely((hdr_size < min_hdr_size) ||
1432 		     (size < hdr_size) ||
1433 		     (buf->len < size) ||
1434 		     (size - hdr_size > TIPC_MAX_USER_MSG_SIZE)))
1435 		return 0;
1436 
1437 	return pskb_may_pull(buf, hdr_size);
1438 }
1439 
1440 /**
1441  * tipc_rcv - process TIPC packets/messages arriving from off-node
1442  * @head: pointer to message buffer chain
1443  * @tb_ptr: pointer to bearer message arrived on
1444  *
1445  * Invoked with no locks held.  Bearer pointer must point to a valid bearer
1446  * structure (i.e. cannot be NULL), but bearer can be inactive.
1447  */
1448 void tipc_rcv(struct sk_buff *head, struct tipc_bearer *b_ptr)
1449 {
1450 	read_lock_bh(&tipc_net_lock);
1451 	while (head) {
1452 		struct tipc_node *n_ptr;
1453 		struct tipc_link *l_ptr;
1454 		struct sk_buff *crs;
1455 		struct sk_buff *buf = head;
1456 		struct tipc_msg *msg;
1457 		u32 seq_no;
1458 		u32 ackd;
1459 		u32 released = 0;
1460 
1461 		head = head->next;
1462 		buf->next = NULL;
1463 
1464 		/* Ensure message is well-formed */
1465 		if (unlikely(!link_recv_buf_validate(buf)))
1466 			goto discard;
1467 
1468 		/* Ensure message data is a single contiguous unit */
1469 		if (unlikely(skb_linearize(buf)))
1470 			goto discard;
1471 
1472 		/* Handle arrival of a non-unicast link message */
1473 		msg = buf_msg(buf);
1474 
1475 		if (unlikely(msg_non_seq(msg))) {
1476 			if (msg_user(msg) ==  LINK_CONFIG)
1477 				tipc_disc_rcv(buf, b_ptr);
1478 			else
1479 				tipc_bclink_rcv(buf);
1480 			continue;
1481 		}
1482 
1483 		/* Discard unicast link messages destined for another node */
1484 		if (unlikely(!msg_short(msg) &&
1485 			     (msg_destnode(msg) != tipc_own_addr)))
1486 			goto discard;
1487 
1488 		/* Locate neighboring node that sent message */
1489 		n_ptr = tipc_node_find(msg_prevnode(msg));
1490 		if (unlikely(!n_ptr))
1491 			goto discard;
1492 		tipc_node_lock(n_ptr);
1493 
1494 		/* Locate unicast link endpoint that should handle message */
1495 		l_ptr = n_ptr->links[b_ptr->identity];
1496 		if (unlikely(!l_ptr))
1497 			goto unlock_discard;
1498 
1499 		/* Verify that communication with node is currently allowed */
1500 		if ((n_ptr->block_setup & WAIT_PEER_DOWN) &&
1501 			msg_user(msg) == LINK_PROTOCOL &&
1502 			(msg_type(msg) == RESET_MSG ||
1503 			 msg_type(msg) == ACTIVATE_MSG) &&
1504 			!msg_redundant_link(msg))
1505 			n_ptr->block_setup &= ~WAIT_PEER_DOWN;
1506 
1507 		if (n_ptr->block_setup)
1508 			goto unlock_discard;
1509 
1510 		/* Validate message sequence number info */
1511 		seq_no = msg_seqno(msg);
1512 		ackd = msg_ack(msg);
1513 
1514 		/* Release acked messages */
1515 		if (n_ptr->bclink.recv_permitted)
1516 			tipc_bclink_acknowledge(n_ptr, msg_bcast_ack(msg));
1517 
1518 		crs = l_ptr->first_out;
1519 		while ((crs != l_ptr->next_out) &&
1520 		       less_eq(buf_seqno(crs), ackd)) {
1521 			struct sk_buff *next = crs->next;
1522 			kfree_skb(crs);
1523 			crs = next;
1524 			released++;
1525 		}
1526 		if (released) {
1527 			l_ptr->first_out = crs;
1528 			l_ptr->out_queue_size -= released;
1529 		}
1530 
1531 		/* Try sending any messages link endpoint has pending */
1532 		if (unlikely(l_ptr->next_out))
1533 			tipc_link_push_queue(l_ptr);
1534 
1535 		if (unlikely(!list_empty(&l_ptr->waiting_ports)))
1536 			tipc_link_wakeup_ports(l_ptr, 0);
1537 
1538 		if (unlikely(++l_ptr->unacked_window >= TIPC_MIN_LINK_WIN)) {
1539 			l_ptr->stats.sent_acks++;
1540 			tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
1541 		}
1542 
1543 		/* Process the incoming packet */
1544 		if (unlikely(!link_working_working(l_ptr))) {
1545 			if (msg_user(msg) == LINK_PROTOCOL) {
1546 				tipc_link_proto_rcv(l_ptr, buf);
1547 				head = link_insert_deferred_queue(l_ptr, head);
1548 				tipc_node_unlock(n_ptr);
1549 				continue;
1550 			}
1551 
1552 			/* Traffic message. Conditionally activate link */
1553 			link_state_event(l_ptr, TRAFFIC_MSG_EVT);
1554 
1555 			if (link_working_working(l_ptr)) {
1556 				/* Re-insert buffer in front of queue */
1557 				buf->next = head;
1558 				head = buf;
1559 				tipc_node_unlock(n_ptr);
1560 				continue;
1561 			}
1562 			goto unlock_discard;
1563 		}
1564 
1565 		/* Link is now in state WORKING_WORKING */
1566 		if (unlikely(seq_no != mod(l_ptr->next_in_no))) {
1567 			link_handle_out_of_seq_msg(l_ptr, buf);
1568 			head = link_insert_deferred_queue(l_ptr, head);
1569 			tipc_node_unlock(n_ptr);
1570 			continue;
1571 		}
1572 		l_ptr->next_in_no++;
1573 		if (unlikely(l_ptr->oldest_deferred_in))
1574 			head = link_insert_deferred_queue(l_ptr, head);
1575 
1576 		/* Deliver packet/message to correct user: */
1577 		if (unlikely(msg_user(msg) ==  CHANGEOVER_PROTOCOL)) {
1578 			if (!tipc_link_tunnel_rcv(n_ptr, &buf)) {
1579 				tipc_node_unlock(n_ptr);
1580 				continue;
1581 			}
1582 			msg = buf_msg(buf);
1583 		} else if (msg_user(msg) == MSG_FRAGMENTER) {
1584 			int rc;
1585 
1586 			l_ptr->stats.recv_fragments++;
1587 			rc = tipc_link_frag_rcv(&l_ptr->reasm_head,
1588 						&l_ptr->reasm_tail,
1589 						&buf);
1590 			if (rc == LINK_REASM_COMPLETE) {
1591 				l_ptr->stats.recv_fragmented++;
1592 				msg = buf_msg(buf);
1593 			} else {
1594 				if (rc == LINK_REASM_ERROR)
1595 					tipc_link_reset(l_ptr);
1596 				tipc_node_unlock(n_ptr);
1597 				continue;
1598 			}
1599 		}
1600 
1601 		switch (msg_user(msg)) {
1602 		case TIPC_LOW_IMPORTANCE:
1603 		case TIPC_MEDIUM_IMPORTANCE:
1604 		case TIPC_HIGH_IMPORTANCE:
1605 		case TIPC_CRITICAL_IMPORTANCE:
1606 			tipc_node_unlock(n_ptr);
1607 			tipc_port_rcv(buf);
1608 			continue;
1609 		case MSG_BUNDLER:
1610 			l_ptr->stats.recv_bundles++;
1611 			l_ptr->stats.recv_bundled += msg_msgcnt(msg);
1612 			tipc_node_unlock(n_ptr);
1613 			tipc_link_bundle_rcv(buf);
1614 			continue;
1615 		case NAME_DISTRIBUTOR:
1616 			n_ptr->bclink.recv_permitted = true;
1617 			tipc_node_unlock(n_ptr);
1618 			tipc_named_rcv(buf);
1619 			continue;
1620 		case CONN_MANAGER:
1621 			tipc_node_unlock(n_ptr);
1622 			tipc_port_proto_rcv(buf);
1623 			continue;
1624 		case BCAST_PROTOCOL:
1625 			tipc_link_sync_rcv(n_ptr, buf);
1626 			break;
1627 		default:
1628 			kfree_skb(buf);
1629 			break;
1630 		}
1631 		tipc_node_unlock(n_ptr);
1632 		continue;
1633 unlock_discard:
1634 		tipc_node_unlock(n_ptr);
1635 discard:
1636 		kfree_skb(buf);
1637 	}
1638 	read_unlock_bh(&tipc_net_lock);
1639 }
1640 
1641 /**
1642  * tipc_link_defer_pkt - Add out-of-sequence message to deferred reception queue
1643  *
1644  * Returns increase in queue length (i.e. 0 or 1)
1645  */
1646 u32 tipc_link_defer_pkt(struct sk_buff **head, struct sk_buff **tail,
1647 			struct sk_buff *buf)
1648 {
1649 	struct sk_buff *queue_buf;
1650 	struct sk_buff **prev;
1651 	u32 seq_no = buf_seqno(buf);
1652 
1653 	buf->next = NULL;
1654 
1655 	/* Empty queue ? */
1656 	if (*head == NULL) {
1657 		*head = *tail = buf;
1658 		return 1;
1659 	}
1660 
1661 	/* Last ? */
1662 	if (less(buf_seqno(*tail), seq_no)) {
1663 		(*tail)->next = buf;
1664 		*tail = buf;
1665 		return 1;
1666 	}
1667 
1668 	/* Locate insertion point in queue, then insert; discard if duplicate */
1669 	prev = head;
1670 	queue_buf = *head;
1671 	for (;;) {
1672 		u32 curr_seqno = buf_seqno(queue_buf);
1673 
1674 		if (seq_no == curr_seqno) {
1675 			kfree_skb(buf);
1676 			return 0;
1677 		}
1678 
1679 		if (less(seq_no, curr_seqno))
1680 			break;
1681 
1682 		prev = &queue_buf->next;
1683 		queue_buf = queue_buf->next;
1684 	}
1685 
1686 	buf->next = queue_buf;
1687 	*prev = buf;
1688 	return 1;
1689 }
1690 
1691 /*
1692  * link_handle_out_of_seq_msg - handle arrival of out-of-sequence packet
1693  */
1694 static void link_handle_out_of_seq_msg(struct tipc_link *l_ptr,
1695 				       struct sk_buff *buf)
1696 {
1697 	u32 seq_no = buf_seqno(buf);
1698 
1699 	if (likely(msg_user(buf_msg(buf)) == LINK_PROTOCOL)) {
1700 		tipc_link_proto_rcv(l_ptr, buf);
1701 		return;
1702 	}
1703 
1704 	/* Record OOS packet arrival (force mismatch on next timeout) */
1705 	l_ptr->checkpoint--;
1706 
1707 	/*
1708 	 * Discard packet if a duplicate; otherwise add it to deferred queue
1709 	 * and notify peer of gap as per protocol specification
1710 	 */
1711 	if (less(seq_no, mod(l_ptr->next_in_no))) {
1712 		l_ptr->stats.duplicates++;
1713 		kfree_skb(buf);
1714 		return;
1715 	}
1716 
1717 	if (tipc_link_defer_pkt(&l_ptr->oldest_deferred_in,
1718 				&l_ptr->newest_deferred_in, buf)) {
1719 		l_ptr->deferred_inqueue_sz++;
1720 		l_ptr->stats.deferred_recv++;
1721 		TIPC_SKB_CB(buf)->deferred = true;
1722 		if ((l_ptr->deferred_inqueue_sz % 16) == 1)
1723 			tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
1724 	} else
1725 		l_ptr->stats.duplicates++;
1726 }
1727 
1728 /*
1729  * Send protocol message to the other endpoint.
1730  */
1731 void tipc_link_proto_xmit(struct tipc_link *l_ptr, u32 msg_typ, int probe_msg,
1732 			  u32 gap, u32 tolerance, u32 priority, u32 ack_mtu)
1733 {
1734 	struct sk_buff *buf = NULL;
1735 	struct tipc_msg *msg = l_ptr->pmsg;
1736 	u32 msg_size = sizeof(l_ptr->proto_msg);
1737 	int r_flag;
1738 
1739 	/* Discard any previous message that was deferred due to congestion */
1740 	if (l_ptr->proto_msg_queue) {
1741 		kfree_skb(l_ptr->proto_msg_queue);
1742 		l_ptr->proto_msg_queue = NULL;
1743 	}
1744 
1745 	/* Don't send protocol message during link changeover */
1746 	if (l_ptr->exp_msg_count)
1747 		return;
1748 
1749 	/* Abort non-RESET send if communication with node is prohibited */
1750 	if ((l_ptr->owner->block_setup) && (msg_typ != RESET_MSG))
1751 		return;
1752 
1753 	/* Create protocol message with "out-of-sequence" sequence number */
1754 	msg_set_type(msg, msg_typ);
1755 	msg_set_net_plane(msg, l_ptr->b_ptr->net_plane);
1756 	msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1757 	msg_set_last_bcast(msg, tipc_bclink_get_last_sent());
1758 
1759 	if (msg_typ == STATE_MSG) {
1760 		u32 next_sent = mod(l_ptr->next_out_no);
1761 
1762 		if (!tipc_link_is_up(l_ptr))
1763 			return;
1764 		if (l_ptr->next_out)
1765 			next_sent = buf_seqno(l_ptr->next_out);
1766 		msg_set_next_sent(msg, next_sent);
1767 		if (l_ptr->oldest_deferred_in) {
1768 			u32 rec = buf_seqno(l_ptr->oldest_deferred_in);
1769 			gap = mod(rec - mod(l_ptr->next_in_no));
1770 		}
1771 		msg_set_seq_gap(msg, gap);
1772 		if (gap)
1773 			l_ptr->stats.sent_nacks++;
1774 		msg_set_link_tolerance(msg, tolerance);
1775 		msg_set_linkprio(msg, priority);
1776 		msg_set_max_pkt(msg, ack_mtu);
1777 		msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1778 		msg_set_probe(msg, probe_msg != 0);
1779 		if (probe_msg) {
1780 			u32 mtu = l_ptr->max_pkt;
1781 
1782 			if ((mtu < l_ptr->max_pkt_target) &&
1783 			    link_working_working(l_ptr) &&
1784 			    l_ptr->fsm_msg_cnt) {
1785 				msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
1786 				if (l_ptr->max_pkt_probes == 10) {
1787 					l_ptr->max_pkt_target = (msg_size - 4);
1788 					l_ptr->max_pkt_probes = 0;
1789 					msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
1790 				}
1791 				l_ptr->max_pkt_probes++;
1792 			}
1793 
1794 			l_ptr->stats.sent_probes++;
1795 		}
1796 		l_ptr->stats.sent_states++;
1797 	} else {		/* RESET_MSG or ACTIVATE_MSG */
1798 		msg_set_ack(msg, mod(l_ptr->reset_checkpoint - 1));
1799 		msg_set_seq_gap(msg, 0);
1800 		msg_set_next_sent(msg, 1);
1801 		msg_set_probe(msg, 0);
1802 		msg_set_link_tolerance(msg, l_ptr->tolerance);
1803 		msg_set_linkprio(msg, l_ptr->priority);
1804 		msg_set_max_pkt(msg, l_ptr->max_pkt_target);
1805 	}
1806 
1807 	r_flag = (l_ptr->owner->working_links > tipc_link_is_up(l_ptr));
1808 	msg_set_redundant_link(msg, r_flag);
1809 	msg_set_linkprio(msg, l_ptr->priority);
1810 	msg_set_size(msg, msg_size);
1811 
1812 	msg_set_seqno(msg, mod(l_ptr->next_out_no + (0xffff/2)));
1813 
1814 	buf = tipc_buf_acquire(msg_size);
1815 	if (!buf)
1816 		return;
1817 
1818 	skb_copy_to_linear_data(buf, msg, sizeof(l_ptr->proto_msg));
1819 	buf->priority = TC_PRIO_CONTROL;
1820 
1821 	tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr);
1822 	l_ptr->unacked_window = 0;
1823 	kfree_skb(buf);
1824 }
1825 
1826 /*
1827  * Receive protocol message :
1828  * Note that network plane id propagates through the network, and may
1829  * change at any time. The node with lowest address rules
1830  */
1831 static void tipc_link_proto_rcv(struct tipc_link *l_ptr, struct sk_buff *buf)
1832 {
1833 	u32 rec_gap = 0;
1834 	u32 max_pkt_info;
1835 	u32 max_pkt_ack;
1836 	u32 msg_tol;
1837 	struct tipc_msg *msg = buf_msg(buf);
1838 
1839 	/* Discard protocol message during link changeover */
1840 	if (l_ptr->exp_msg_count)
1841 		goto exit;
1842 
1843 	/* record unnumbered packet arrival (force mismatch on next timeout) */
1844 	l_ptr->checkpoint--;
1845 
1846 	if (l_ptr->b_ptr->net_plane != msg_net_plane(msg))
1847 		if (tipc_own_addr > msg_prevnode(msg))
1848 			l_ptr->b_ptr->net_plane = msg_net_plane(msg);
1849 
1850 	switch (msg_type(msg)) {
1851 
1852 	case RESET_MSG:
1853 		if (!link_working_unknown(l_ptr) &&
1854 		    (l_ptr->peer_session != INVALID_SESSION)) {
1855 			if (less_eq(msg_session(msg), l_ptr->peer_session))
1856 				break; /* duplicate or old reset: ignore */
1857 		}
1858 
1859 		if (!msg_redundant_link(msg) && (link_working_working(l_ptr) ||
1860 				link_working_unknown(l_ptr))) {
1861 			/*
1862 			 * peer has lost contact -- don't allow peer's links
1863 			 * to reactivate before we recognize loss & clean up
1864 			 */
1865 			l_ptr->owner->block_setup = WAIT_NODE_DOWN;
1866 		}
1867 
1868 		link_state_event(l_ptr, RESET_MSG);
1869 
1870 		/* fall thru' */
1871 	case ACTIVATE_MSG:
1872 		/* Update link settings according other endpoint's values */
1873 		strcpy((strrchr(l_ptr->name, ':') + 1), (char *)msg_data(msg));
1874 
1875 		msg_tol = msg_link_tolerance(msg);
1876 		if (msg_tol > l_ptr->tolerance)
1877 			link_set_supervision_props(l_ptr, msg_tol);
1878 
1879 		if (msg_linkprio(msg) > l_ptr->priority)
1880 			l_ptr->priority = msg_linkprio(msg);
1881 
1882 		max_pkt_info = msg_max_pkt(msg);
1883 		if (max_pkt_info) {
1884 			if (max_pkt_info < l_ptr->max_pkt_target)
1885 				l_ptr->max_pkt_target = max_pkt_info;
1886 			if (l_ptr->max_pkt > l_ptr->max_pkt_target)
1887 				l_ptr->max_pkt = l_ptr->max_pkt_target;
1888 		} else {
1889 			l_ptr->max_pkt = l_ptr->max_pkt_target;
1890 		}
1891 
1892 		/* Synchronize broadcast link info, if not done previously */
1893 		if (!tipc_node_is_up(l_ptr->owner)) {
1894 			l_ptr->owner->bclink.last_sent =
1895 				l_ptr->owner->bclink.last_in =
1896 				msg_last_bcast(msg);
1897 			l_ptr->owner->bclink.oos_state = 0;
1898 		}
1899 
1900 		l_ptr->peer_session = msg_session(msg);
1901 		l_ptr->peer_bearer_id = msg_bearer_id(msg);
1902 
1903 		if (msg_type(msg) == ACTIVATE_MSG)
1904 			link_state_event(l_ptr, ACTIVATE_MSG);
1905 		break;
1906 	case STATE_MSG:
1907 
1908 		msg_tol = msg_link_tolerance(msg);
1909 		if (msg_tol)
1910 			link_set_supervision_props(l_ptr, msg_tol);
1911 
1912 		if (msg_linkprio(msg) &&
1913 		    (msg_linkprio(msg) != l_ptr->priority)) {
1914 			pr_warn("%s<%s>, priority change %u->%u\n",
1915 				link_rst_msg, l_ptr->name, l_ptr->priority,
1916 				msg_linkprio(msg));
1917 			l_ptr->priority = msg_linkprio(msg);
1918 			tipc_link_reset(l_ptr); /* Enforce change to take effect */
1919 			break;
1920 		}
1921 		link_state_event(l_ptr, TRAFFIC_MSG_EVT);
1922 		l_ptr->stats.recv_states++;
1923 		if (link_reset_unknown(l_ptr))
1924 			break;
1925 
1926 		if (less_eq(mod(l_ptr->next_in_no), msg_next_sent(msg))) {
1927 			rec_gap = mod(msg_next_sent(msg) -
1928 				      mod(l_ptr->next_in_no));
1929 		}
1930 
1931 		max_pkt_ack = msg_max_pkt(msg);
1932 		if (max_pkt_ack > l_ptr->max_pkt) {
1933 			l_ptr->max_pkt = max_pkt_ack;
1934 			l_ptr->max_pkt_probes = 0;
1935 		}
1936 
1937 		max_pkt_ack = 0;
1938 		if (msg_probe(msg)) {
1939 			l_ptr->stats.recv_probes++;
1940 			if (msg_size(msg) > sizeof(l_ptr->proto_msg))
1941 				max_pkt_ack = msg_size(msg);
1942 		}
1943 
1944 		/* Protocol message before retransmits, reduce loss risk */
1945 		if (l_ptr->owner->bclink.recv_permitted)
1946 			tipc_bclink_update_link_state(l_ptr->owner,
1947 						      msg_last_bcast(msg));
1948 
1949 		if (rec_gap || (msg_probe(msg))) {
1950 			tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, rec_gap, 0,
1951 					     0, max_pkt_ack);
1952 		}
1953 		if (msg_seq_gap(msg)) {
1954 			l_ptr->stats.recv_nacks++;
1955 			tipc_link_retransmit(l_ptr, l_ptr->first_out,
1956 					     msg_seq_gap(msg));
1957 		}
1958 		break;
1959 	}
1960 exit:
1961 	kfree_skb(buf);
1962 }
1963 
1964 
1965 /* tipc_link_tunnel_xmit(): Tunnel one packet via a link belonging to
1966  * a different bearer. Owner node is locked.
1967  */
1968 static void tipc_link_tunnel_xmit(struct tipc_link *l_ptr,
1969 				  struct tipc_msg *tunnel_hdr,
1970 				  struct tipc_msg *msg,
1971 				  u32 selector)
1972 {
1973 	struct tipc_link *tunnel;
1974 	struct sk_buff *buf;
1975 	u32 length = msg_size(msg);
1976 
1977 	tunnel = l_ptr->owner->active_links[selector & 1];
1978 	if (!tipc_link_is_up(tunnel)) {
1979 		pr_warn("%stunnel link no longer available\n", link_co_err);
1980 		return;
1981 	}
1982 	msg_set_size(tunnel_hdr, length + INT_H_SIZE);
1983 	buf = tipc_buf_acquire(length + INT_H_SIZE);
1984 	if (!buf) {
1985 		pr_warn("%sunable to send tunnel msg\n", link_co_err);
1986 		return;
1987 	}
1988 	skb_copy_to_linear_data(buf, tunnel_hdr, INT_H_SIZE);
1989 	skb_copy_to_linear_data_offset(buf, INT_H_SIZE, msg, length);
1990 	__tipc_link_xmit(tunnel, buf);
1991 }
1992 
1993 
1994 /* tipc_link_failover_send_queue(): A link has gone down, but a second
1995  * link is still active. We can do failover. Tunnel the failing link's
1996  * whole send queue via the remaining link. This way, we don't lose
1997  * any packets, and sequence order is preserved for subsequent traffic
1998  * sent over the remaining link. Owner node is locked.
1999  */
2000 void tipc_link_failover_send_queue(struct tipc_link *l_ptr)
2001 {
2002 	u32 msgcount = l_ptr->out_queue_size;
2003 	struct sk_buff *crs = l_ptr->first_out;
2004 	struct tipc_link *tunnel = l_ptr->owner->active_links[0];
2005 	struct tipc_msg tunnel_hdr;
2006 	int split_bundles;
2007 
2008 	if (!tunnel)
2009 		return;
2010 
2011 	tipc_msg_init(&tunnel_hdr, CHANGEOVER_PROTOCOL,
2012 		 ORIGINAL_MSG, INT_H_SIZE, l_ptr->addr);
2013 	msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
2014 	msg_set_msgcnt(&tunnel_hdr, msgcount);
2015 
2016 	if (!l_ptr->first_out) {
2017 		struct sk_buff *buf;
2018 
2019 		buf = tipc_buf_acquire(INT_H_SIZE);
2020 		if (buf) {
2021 			skb_copy_to_linear_data(buf, &tunnel_hdr, INT_H_SIZE);
2022 			msg_set_size(&tunnel_hdr, INT_H_SIZE);
2023 			__tipc_link_xmit(tunnel, buf);
2024 		} else {
2025 			pr_warn("%sunable to send changeover msg\n",
2026 				link_co_err);
2027 		}
2028 		return;
2029 	}
2030 
2031 	split_bundles = (l_ptr->owner->active_links[0] !=
2032 			 l_ptr->owner->active_links[1]);
2033 
2034 	while (crs) {
2035 		struct tipc_msg *msg = buf_msg(crs);
2036 
2037 		if ((msg_user(msg) == MSG_BUNDLER) && split_bundles) {
2038 			struct tipc_msg *m = msg_get_wrapped(msg);
2039 			unchar *pos = (unchar *)m;
2040 
2041 			msgcount = msg_msgcnt(msg);
2042 			while (msgcount--) {
2043 				msg_set_seqno(m, msg_seqno(msg));
2044 				tipc_link_tunnel_xmit(l_ptr, &tunnel_hdr, m,
2045 						      msg_link_selector(m));
2046 				pos += align(msg_size(m));
2047 				m = (struct tipc_msg *)pos;
2048 			}
2049 		} else {
2050 			tipc_link_tunnel_xmit(l_ptr, &tunnel_hdr, msg,
2051 					      msg_link_selector(msg));
2052 		}
2053 		crs = crs->next;
2054 	}
2055 }
2056 
2057 /* tipc_link_dup_queue_xmit(): A second link has become active. Tunnel a
2058  * duplicate of the first link's send queue via the new link. This way, we
2059  * are guaranteed that currently queued packets from a socket are delivered
2060  * before future traffic from the same socket, even if this is using the
2061  * new link. The last arriving copy of each duplicate packet is dropped at
2062  * the receiving end by the regular protocol check, so packet cardinality
2063  * and sequence order is preserved per sender/receiver socket pair.
2064  * Owner node is locked.
2065  */
2066 void tipc_link_dup_queue_xmit(struct tipc_link *l_ptr,
2067 			      struct tipc_link *tunnel)
2068 {
2069 	struct sk_buff *iter;
2070 	struct tipc_msg tunnel_hdr;
2071 
2072 	tipc_msg_init(&tunnel_hdr, CHANGEOVER_PROTOCOL,
2073 		 DUPLICATE_MSG, INT_H_SIZE, l_ptr->addr);
2074 	msg_set_msgcnt(&tunnel_hdr, l_ptr->out_queue_size);
2075 	msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
2076 	iter = l_ptr->first_out;
2077 	while (iter) {
2078 		struct sk_buff *outbuf;
2079 		struct tipc_msg *msg = buf_msg(iter);
2080 		u32 length = msg_size(msg);
2081 
2082 		if (msg_user(msg) == MSG_BUNDLER)
2083 			msg_set_type(msg, CLOSED_MSG);
2084 		msg_set_ack(msg, mod(l_ptr->next_in_no - 1));	/* Update */
2085 		msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
2086 		msg_set_size(&tunnel_hdr, length + INT_H_SIZE);
2087 		outbuf = tipc_buf_acquire(length + INT_H_SIZE);
2088 		if (outbuf == NULL) {
2089 			pr_warn("%sunable to send duplicate msg\n",
2090 				link_co_err);
2091 			return;
2092 		}
2093 		skb_copy_to_linear_data(outbuf, &tunnel_hdr, INT_H_SIZE);
2094 		skb_copy_to_linear_data_offset(outbuf, INT_H_SIZE, iter->data,
2095 					       length);
2096 		__tipc_link_xmit(tunnel, outbuf);
2097 		if (!tipc_link_is_up(l_ptr))
2098 			return;
2099 		iter = iter->next;
2100 	}
2101 }
2102 
2103 /**
2104  * buf_extract - extracts embedded TIPC message from another message
2105  * @skb: encapsulating message buffer
2106  * @from_pos: offset to extract from
2107  *
2108  * Returns a new message buffer containing an embedded message.  The
2109  * encapsulating message itself is left unchanged.
2110  */
2111 static struct sk_buff *buf_extract(struct sk_buff *skb, u32 from_pos)
2112 {
2113 	struct tipc_msg *msg = (struct tipc_msg *)(skb->data + from_pos);
2114 	u32 size = msg_size(msg);
2115 	struct sk_buff *eb;
2116 
2117 	eb = tipc_buf_acquire(size);
2118 	if (eb)
2119 		skb_copy_to_linear_data(eb, msg, size);
2120 	return eb;
2121 }
2122 
2123 
2124 
2125 /* tipc_link_dup_rcv(): Receive a tunnelled DUPLICATE_MSG packet.
2126  * Owner node is locked.
2127  */
2128 static void tipc_link_dup_rcv(struct tipc_link *l_ptr,
2129 			      struct sk_buff *t_buf)
2130 {
2131 	struct sk_buff *buf;
2132 
2133 	if (!tipc_link_is_up(l_ptr))
2134 		return;
2135 
2136 	buf = buf_extract(t_buf, INT_H_SIZE);
2137 	if (buf == NULL) {
2138 		pr_warn("%sfailed to extract inner dup pkt\n", link_co_err);
2139 		return;
2140 	}
2141 
2142 	/* Add buffer to deferred queue, if applicable: */
2143 	link_handle_out_of_seq_msg(l_ptr, buf);
2144 }
2145 
2146 /*  tipc_link_failover_rcv(): Receive a tunnelled ORIGINAL_MSG packet
2147  *  Owner node is locked.
2148  */
2149 static struct sk_buff *tipc_link_failover_rcv(struct tipc_link *l_ptr,
2150 					      struct sk_buff *t_buf)
2151 {
2152 	struct tipc_msg *t_msg = buf_msg(t_buf);
2153 	struct sk_buff *buf = NULL;
2154 	struct tipc_msg *msg;
2155 
2156 	if (tipc_link_is_up(l_ptr))
2157 		tipc_link_reset(l_ptr);
2158 
2159 	/* First failover packet? */
2160 	if (l_ptr->exp_msg_count == START_CHANGEOVER)
2161 		l_ptr->exp_msg_count = msg_msgcnt(t_msg);
2162 
2163 	/* Should there be an inner packet? */
2164 	if (l_ptr->exp_msg_count) {
2165 		l_ptr->exp_msg_count--;
2166 		buf = buf_extract(t_buf, INT_H_SIZE);
2167 		if (buf == NULL) {
2168 			pr_warn("%sno inner failover pkt\n", link_co_err);
2169 			goto exit;
2170 		}
2171 		msg = buf_msg(buf);
2172 
2173 		if (less(msg_seqno(msg), l_ptr->reset_checkpoint)) {
2174 			kfree_skb(buf);
2175 			buf = NULL;
2176 			goto exit;
2177 		}
2178 		if (msg_user(msg) == MSG_FRAGMENTER) {
2179 			l_ptr->stats.recv_fragments++;
2180 			tipc_link_frag_rcv(&l_ptr->reasm_head,
2181 					   &l_ptr->reasm_tail,
2182 					   &buf);
2183 		}
2184 	}
2185 exit:
2186 	if ((l_ptr->exp_msg_count == 0) && (l_ptr->flags & LINK_STOPPED)) {
2187 		tipc_node_detach_link(l_ptr->owner, l_ptr);
2188 		kfree(l_ptr);
2189 	}
2190 	return buf;
2191 }
2192 
2193 /*  tipc_link_tunnel_rcv(): Receive a tunnelled packet, sent
2194  *  via other link as result of a failover (ORIGINAL_MSG) or
2195  *  a new active link (DUPLICATE_MSG). Failover packets are
2196  *  returned to the active link for delivery upwards.
2197  *  Owner node is locked.
2198  */
2199 static int tipc_link_tunnel_rcv(struct tipc_node *n_ptr,
2200 				struct sk_buff **buf)
2201 {
2202 	struct sk_buff *t_buf = *buf;
2203 	struct tipc_link *l_ptr;
2204 	struct tipc_msg *t_msg = buf_msg(t_buf);
2205 	u32 bearer_id = msg_bearer_id(t_msg);
2206 
2207 	*buf = NULL;
2208 
2209 	if (bearer_id >= MAX_BEARERS)
2210 		goto exit;
2211 
2212 	l_ptr = n_ptr->links[bearer_id];
2213 	if (!l_ptr)
2214 		goto exit;
2215 
2216 	if (msg_type(t_msg) == DUPLICATE_MSG)
2217 		tipc_link_dup_rcv(l_ptr, t_buf);
2218 	else if (msg_type(t_msg) == ORIGINAL_MSG)
2219 		*buf = tipc_link_failover_rcv(l_ptr, t_buf);
2220 	else
2221 		pr_warn("%sunknown tunnel pkt received\n", link_co_err);
2222 exit:
2223 	kfree_skb(t_buf);
2224 	return *buf != NULL;
2225 }
2226 
2227 /*
2228  *  Bundler functionality:
2229  */
2230 void tipc_link_bundle_rcv(struct sk_buff *buf)
2231 {
2232 	u32 msgcount = msg_msgcnt(buf_msg(buf));
2233 	u32 pos = INT_H_SIZE;
2234 	struct sk_buff *obuf;
2235 
2236 	while (msgcount--) {
2237 		obuf = buf_extract(buf, pos);
2238 		if (obuf == NULL) {
2239 			pr_warn("Link unable to unbundle message(s)\n");
2240 			break;
2241 		}
2242 		pos += align(msg_size(buf_msg(obuf)));
2243 		tipc_net_route_msg(obuf);
2244 	}
2245 	kfree_skb(buf);
2246 }
2247 
2248 /*
2249  *  Fragmentation/defragmentation:
2250  */
2251 
2252 /*
2253  * tipc_link_frag_xmit: Entry for buffers needing fragmentation.
2254  * The buffer is complete, inclusive total message length.
2255  * Returns user data length.
2256  */
2257 static int tipc_link_frag_xmit(struct tipc_link *l_ptr, struct sk_buff *buf)
2258 {
2259 	struct sk_buff *buf_chain = NULL;
2260 	struct sk_buff *buf_chain_tail = (struct sk_buff *)&buf_chain;
2261 	struct tipc_msg *inmsg = buf_msg(buf);
2262 	struct tipc_msg fragm_hdr;
2263 	u32 insize = msg_size(inmsg);
2264 	u32 dsz = msg_data_sz(inmsg);
2265 	unchar *crs = buf->data;
2266 	u32 rest = insize;
2267 	u32 pack_sz = l_ptr->max_pkt;
2268 	u32 fragm_sz = pack_sz - INT_H_SIZE;
2269 	u32 fragm_no = 0;
2270 	u32 destaddr;
2271 
2272 	if (msg_short(inmsg))
2273 		destaddr = l_ptr->addr;
2274 	else
2275 		destaddr = msg_destnode(inmsg);
2276 
2277 	/* Prepare reusable fragment header: */
2278 	tipc_msg_init(&fragm_hdr, MSG_FRAGMENTER, FIRST_FRAGMENT,
2279 		 INT_H_SIZE, destaddr);
2280 
2281 	/* Chop up message: */
2282 	while (rest > 0) {
2283 		struct sk_buff *fragm;
2284 
2285 		if (rest <= fragm_sz) {
2286 			fragm_sz = rest;
2287 			msg_set_type(&fragm_hdr, LAST_FRAGMENT);
2288 		}
2289 		fragm = tipc_buf_acquire(fragm_sz + INT_H_SIZE);
2290 		if (fragm == NULL) {
2291 			kfree_skb(buf);
2292 			kfree_skb_list(buf_chain);
2293 			return -ENOMEM;
2294 		}
2295 		msg_set_size(&fragm_hdr, fragm_sz + INT_H_SIZE);
2296 		fragm_no++;
2297 		msg_set_fragm_no(&fragm_hdr, fragm_no);
2298 		skb_copy_to_linear_data(fragm, &fragm_hdr, INT_H_SIZE);
2299 		skb_copy_to_linear_data_offset(fragm, INT_H_SIZE, crs,
2300 					       fragm_sz);
2301 		buf_chain_tail->next = fragm;
2302 		buf_chain_tail = fragm;
2303 
2304 		rest -= fragm_sz;
2305 		crs += fragm_sz;
2306 		msg_set_type(&fragm_hdr, FRAGMENT);
2307 	}
2308 	kfree_skb(buf);
2309 
2310 	/* Append chain of fragments to send queue & send them */
2311 	l_ptr->long_msg_seq_no++;
2312 	link_add_chain_to_outqueue(l_ptr, buf_chain, l_ptr->long_msg_seq_no);
2313 	l_ptr->stats.sent_fragments += fragm_no;
2314 	l_ptr->stats.sent_fragmented++;
2315 	tipc_link_push_queue(l_ptr);
2316 
2317 	return dsz;
2318 }
2319 
2320 /* tipc_link_frag_rcv(): Called with node lock on. Returns
2321  * the reassembled buffer if message is complete.
2322  */
2323 int tipc_link_frag_rcv(struct sk_buff **head, struct sk_buff **tail,
2324 		       struct sk_buff **fbuf)
2325 {
2326 	struct sk_buff *frag = *fbuf;
2327 	struct tipc_msg *msg = buf_msg(frag);
2328 	u32 fragid = msg_type(msg);
2329 	bool headstolen;
2330 	int delta;
2331 
2332 	skb_pull(frag, msg_hdr_sz(msg));
2333 	if (fragid == FIRST_FRAGMENT) {
2334 		if (*head || skb_unclone(frag, GFP_ATOMIC))
2335 			goto out_free;
2336 		*head = frag;
2337 		skb_frag_list_init(*head);
2338 		*fbuf = NULL;
2339 		return 0;
2340 	} else if (*head &&
2341 		   skb_try_coalesce(*head, frag, &headstolen, &delta)) {
2342 		kfree_skb_partial(frag, headstolen);
2343 	} else {
2344 		if (!*head)
2345 			goto out_free;
2346 		if (!skb_has_frag_list(*head))
2347 			skb_shinfo(*head)->frag_list = frag;
2348 		else
2349 			(*tail)->next = frag;
2350 		*tail = frag;
2351 		(*head)->truesize += frag->truesize;
2352 	}
2353 	if (fragid == LAST_FRAGMENT) {
2354 		*fbuf = *head;
2355 		*tail = *head = NULL;
2356 		return LINK_REASM_COMPLETE;
2357 	}
2358 	*fbuf = NULL;
2359 	return 0;
2360 out_free:
2361 	pr_warn_ratelimited("Link unable to reassemble fragmented message\n");
2362 	kfree_skb(*fbuf);
2363 	*fbuf = NULL;
2364 	return LINK_REASM_ERROR;
2365 }
2366 
2367 static void link_set_supervision_props(struct tipc_link *l_ptr, u32 tolerance)
2368 {
2369 	if ((tolerance < TIPC_MIN_LINK_TOL) || (tolerance > TIPC_MAX_LINK_TOL))
2370 		return;
2371 
2372 	l_ptr->tolerance = tolerance;
2373 	l_ptr->continuity_interval =
2374 		((tolerance / 4) > 500) ? 500 : tolerance / 4;
2375 	l_ptr->abort_limit = tolerance / (l_ptr->continuity_interval / 4);
2376 }
2377 
2378 void tipc_link_set_queue_limits(struct tipc_link *l_ptr, u32 window)
2379 {
2380 	/* Data messages from this node, inclusive FIRST_FRAGM */
2381 	l_ptr->queue_limit[TIPC_LOW_IMPORTANCE] = window;
2382 	l_ptr->queue_limit[TIPC_MEDIUM_IMPORTANCE] = (window / 3) * 4;
2383 	l_ptr->queue_limit[TIPC_HIGH_IMPORTANCE] = (window / 3) * 5;
2384 	l_ptr->queue_limit[TIPC_CRITICAL_IMPORTANCE] = (window / 3) * 6;
2385 	/* Transiting data messages,inclusive FIRST_FRAGM */
2386 	l_ptr->queue_limit[TIPC_LOW_IMPORTANCE + 4] = 300;
2387 	l_ptr->queue_limit[TIPC_MEDIUM_IMPORTANCE + 4] = 600;
2388 	l_ptr->queue_limit[TIPC_HIGH_IMPORTANCE + 4] = 900;
2389 	l_ptr->queue_limit[TIPC_CRITICAL_IMPORTANCE + 4] = 1200;
2390 	l_ptr->queue_limit[CONN_MANAGER] = 1200;
2391 	l_ptr->queue_limit[CHANGEOVER_PROTOCOL] = 2500;
2392 	l_ptr->queue_limit[NAME_DISTRIBUTOR] = 3000;
2393 	/* FRAGMENT and LAST_FRAGMENT packets */
2394 	l_ptr->queue_limit[MSG_FRAGMENTER] = 4000;
2395 }
2396 
2397 /* tipc_link_find_owner - locate owner node of link by link's name
2398  * @name: pointer to link name string
2399  * @bearer_id: pointer to index in 'node->links' array where the link was found.
2400  * Caller must hold 'tipc_net_lock' to ensure node and bearer are not deleted;
2401  * this also prevents link deletion.
2402  *
2403  * Returns pointer to node owning the link, or 0 if no matching link is found.
2404  */
2405 static struct tipc_node *tipc_link_find_owner(const char *link_name,
2406 					      unsigned int *bearer_id)
2407 {
2408 	struct tipc_link *l_ptr;
2409 	struct tipc_node *n_ptr;
2410 	struct tipc_node *found_node = 0;
2411 	int i;
2412 
2413 	*bearer_id = 0;
2414 	rcu_read_lock();
2415 	list_for_each_entry_rcu(n_ptr, &tipc_node_list, list) {
2416 		tipc_node_lock(n_ptr);
2417 		for (i = 0; i < MAX_BEARERS; i++) {
2418 			l_ptr = n_ptr->links[i];
2419 			if (l_ptr && !strcmp(l_ptr->name, link_name)) {
2420 				*bearer_id = i;
2421 				found_node = n_ptr;
2422 				break;
2423 			}
2424 		}
2425 		tipc_node_unlock(n_ptr);
2426 		if (found_node)
2427 			break;
2428 	}
2429 	rcu_read_unlock();
2430 
2431 	return found_node;
2432 }
2433 
2434 /**
2435  * link_value_is_valid -- validate proposed link tolerance/priority/window
2436  *
2437  * @cmd: value type (TIPC_CMD_SET_LINK_*)
2438  * @new_value: the new value
2439  *
2440  * Returns 1 if value is within range, 0 if not.
2441  */
2442 static int link_value_is_valid(u16 cmd, u32 new_value)
2443 {
2444 	switch (cmd) {
2445 	case TIPC_CMD_SET_LINK_TOL:
2446 		return (new_value >= TIPC_MIN_LINK_TOL) &&
2447 			(new_value <= TIPC_MAX_LINK_TOL);
2448 	case TIPC_CMD_SET_LINK_PRI:
2449 		return (new_value <= TIPC_MAX_LINK_PRI);
2450 	case TIPC_CMD_SET_LINK_WINDOW:
2451 		return (new_value >= TIPC_MIN_LINK_WIN) &&
2452 			(new_value <= TIPC_MAX_LINK_WIN);
2453 	}
2454 	return 0;
2455 }
2456 
2457 /**
2458  * link_cmd_set_value - change priority/tolerance/window for link/bearer/media
2459  * @name: ptr to link, bearer, or media name
2460  * @new_value: new value of link, bearer, or media setting
2461  * @cmd: which link, bearer, or media attribute to set (TIPC_CMD_SET_LINK_*)
2462  *
2463  * Caller must hold 'tipc_net_lock' to ensure link/bearer/media is not deleted.
2464  *
2465  * Returns 0 if value updated and negative value on error.
2466  */
2467 static int link_cmd_set_value(const char *name, u32 new_value, u16 cmd)
2468 {
2469 	struct tipc_node *node;
2470 	struct tipc_link *l_ptr;
2471 	struct tipc_bearer *b_ptr;
2472 	struct tipc_media *m_ptr;
2473 	int bearer_id;
2474 	int res = 0;
2475 
2476 	node = tipc_link_find_owner(name, &bearer_id);
2477 	if (node) {
2478 		tipc_node_lock(node);
2479 		l_ptr = node->links[bearer_id];
2480 
2481 		if (l_ptr) {
2482 			switch (cmd) {
2483 			case TIPC_CMD_SET_LINK_TOL:
2484 				link_set_supervision_props(l_ptr, new_value);
2485 				tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, 0,
2486 						     new_value, 0, 0);
2487 				break;
2488 			case TIPC_CMD_SET_LINK_PRI:
2489 				l_ptr->priority = new_value;
2490 				tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, 0,
2491 						     0, new_value, 0);
2492 				break;
2493 			case TIPC_CMD_SET_LINK_WINDOW:
2494 				tipc_link_set_queue_limits(l_ptr, new_value);
2495 				break;
2496 			default:
2497 				res = -EINVAL;
2498 				break;
2499 			}
2500 		}
2501 		tipc_node_unlock(node);
2502 		return res;
2503 	}
2504 
2505 	b_ptr = tipc_bearer_find(name);
2506 	if (b_ptr) {
2507 		switch (cmd) {
2508 		case TIPC_CMD_SET_LINK_TOL:
2509 			b_ptr->tolerance = new_value;
2510 			break;
2511 		case TIPC_CMD_SET_LINK_PRI:
2512 			b_ptr->priority = new_value;
2513 			break;
2514 		case TIPC_CMD_SET_LINK_WINDOW:
2515 			b_ptr->window = new_value;
2516 			break;
2517 		default:
2518 			res = -EINVAL;
2519 			break;
2520 		}
2521 		return res;
2522 	}
2523 
2524 	m_ptr = tipc_media_find(name);
2525 	if (!m_ptr)
2526 		return -ENODEV;
2527 	switch (cmd) {
2528 	case TIPC_CMD_SET_LINK_TOL:
2529 		m_ptr->tolerance = new_value;
2530 		break;
2531 	case TIPC_CMD_SET_LINK_PRI:
2532 		m_ptr->priority = new_value;
2533 		break;
2534 	case TIPC_CMD_SET_LINK_WINDOW:
2535 		m_ptr->window = new_value;
2536 		break;
2537 	default:
2538 		res = -EINVAL;
2539 		break;
2540 	}
2541 	return res;
2542 }
2543 
2544 struct sk_buff *tipc_link_cmd_config(const void *req_tlv_area, int req_tlv_space,
2545 				     u16 cmd)
2546 {
2547 	struct tipc_link_config *args;
2548 	u32 new_value;
2549 	int res;
2550 
2551 	if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_CONFIG))
2552 		return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2553 
2554 	args = (struct tipc_link_config *)TLV_DATA(req_tlv_area);
2555 	new_value = ntohl(args->value);
2556 
2557 	if (!link_value_is_valid(cmd, new_value))
2558 		return tipc_cfg_reply_error_string(
2559 			"cannot change, value invalid");
2560 
2561 	if (!strcmp(args->name, tipc_bclink_name)) {
2562 		if ((cmd == TIPC_CMD_SET_LINK_WINDOW) &&
2563 		    (tipc_bclink_set_queue_limits(new_value) == 0))
2564 			return tipc_cfg_reply_none();
2565 		return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
2566 						   " (cannot change setting on broadcast link)");
2567 	}
2568 
2569 	read_lock_bh(&tipc_net_lock);
2570 	res = link_cmd_set_value(args->name, new_value, cmd);
2571 	read_unlock_bh(&tipc_net_lock);
2572 	if (res)
2573 		return tipc_cfg_reply_error_string("cannot change link setting");
2574 
2575 	return tipc_cfg_reply_none();
2576 }
2577 
2578 /**
2579  * link_reset_statistics - reset link statistics
2580  * @l_ptr: pointer to link
2581  */
2582 static void link_reset_statistics(struct tipc_link *l_ptr)
2583 {
2584 	memset(&l_ptr->stats, 0, sizeof(l_ptr->stats));
2585 	l_ptr->stats.sent_info = l_ptr->next_out_no;
2586 	l_ptr->stats.recv_info = l_ptr->next_in_no;
2587 }
2588 
2589 struct sk_buff *tipc_link_cmd_reset_stats(const void *req_tlv_area, int req_tlv_space)
2590 {
2591 	char *link_name;
2592 	struct tipc_link *l_ptr;
2593 	struct tipc_node *node;
2594 	unsigned int bearer_id;
2595 
2596 	if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_NAME))
2597 		return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2598 
2599 	link_name = (char *)TLV_DATA(req_tlv_area);
2600 	if (!strcmp(link_name, tipc_bclink_name)) {
2601 		if (tipc_bclink_reset_stats())
2602 			return tipc_cfg_reply_error_string("link not found");
2603 		return tipc_cfg_reply_none();
2604 	}
2605 	read_lock_bh(&tipc_net_lock);
2606 	node = tipc_link_find_owner(link_name, &bearer_id);
2607 	if (!node) {
2608 		read_unlock_bh(&tipc_net_lock);
2609 		return tipc_cfg_reply_error_string("link not found");
2610 	}
2611 	tipc_node_lock(node);
2612 	l_ptr = node->links[bearer_id];
2613 	if (!l_ptr) {
2614 		tipc_node_unlock(node);
2615 		read_unlock_bh(&tipc_net_lock);
2616 		return tipc_cfg_reply_error_string("link not found");
2617 	}
2618 	link_reset_statistics(l_ptr);
2619 	tipc_node_unlock(node);
2620 	read_unlock_bh(&tipc_net_lock);
2621 	return tipc_cfg_reply_none();
2622 }
2623 
2624 /**
2625  * percent - convert count to a percentage of total (rounding up or down)
2626  */
2627 static u32 percent(u32 count, u32 total)
2628 {
2629 	return (count * 100 + (total / 2)) / total;
2630 }
2631 
2632 /**
2633  * tipc_link_stats - print link statistics
2634  * @name: link name
2635  * @buf: print buffer area
2636  * @buf_size: size of print buffer area
2637  *
2638  * Returns length of print buffer data string (or 0 if error)
2639  */
2640 static int tipc_link_stats(const char *name, char *buf, const u32 buf_size)
2641 {
2642 	struct tipc_link *l;
2643 	struct tipc_stats *s;
2644 	struct tipc_node *node;
2645 	char *status;
2646 	u32 profile_total = 0;
2647 	unsigned int bearer_id;
2648 	int ret;
2649 
2650 	if (!strcmp(name, tipc_bclink_name))
2651 		return tipc_bclink_stats(buf, buf_size);
2652 
2653 	read_lock_bh(&tipc_net_lock);
2654 	node = tipc_link_find_owner(name, &bearer_id);
2655 	if (!node) {
2656 		read_unlock_bh(&tipc_net_lock);
2657 		return 0;
2658 	}
2659 	tipc_node_lock(node);
2660 
2661 	l = node->links[bearer_id];
2662 	if (!l) {
2663 		tipc_node_unlock(node);
2664 		read_unlock_bh(&tipc_net_lock);
2665 		return 0;
2666 	}
2667 
2668 	s = &l->stats;
2669 
2670 	if (tipc_link_is_active(l))
2671 		status = "ACTIVE";
2672 	else if (tipc_link_is_up(l))
2673 		status = "STANDBY";
2674 	else
2675 		status = "DEFUNCT";
2676 
2677 	ret = tipc_snprintf(buf, buf_size, "Link <%s>\n"
2678 			    "  %s  MTU:%u  Priority:%u  Tolerance:%u ms"
2679 			    "  Window:%u packets\n",
2680 			    l->name, status, l->max_pkt, l->priority,
2681 			    l->tolerance, l->queue_limit[0]);
2682 
2683 	ret += tipc_snprintf(buf + ret, buf_size - ret,
2684 			     "  RX packets:%u fragments:%u/%u bundles:%u/%u\n",
2685 			     l->next_in_no - s->recv_info, s->recv_fragments,
2686 			     s->recv_fragmented, s->recv_bundles,
2687 			     s->recv_bundled);
2688 
2689 	ret += tipc_snprintf(buf + ret, buf_size - ret,
2690 			     "  TX packets:%u fragments:%u/%u bundles:%u/%u\n",
2691 			     l->next_out_no - s->sent_info, s->sent_fragments,
2692 			     s->sent_fragmented, s->sent_bundles,
2693 			     s->sent_bundled);
2694 
2695 	profile_total = s->msg_length_counts;
2696 	if (!profile_total)
2697 		profile_total = 1;
2698 
2699 	ret += tipc_snprintf(buf + ret, buf_size - ret,
2700 			     "  TX profile sample:%u packets  average:%u octets\n"
2701 			     "  0-64:%u%% -256:%u%% -1024:%u%% -4096:%u%% "
2702 			     "-16384:%u%% -32768:%u%% -66000:%u%%\n",
2703 			     s->msg_length_counts,
2704 			     s->msg_lengths_total / profile_total,
2705 			     percent(s->msg_length_profile[0], profile_total),
2706 			     percent(s->msg_length_profile[1], profile_total),
2707 			     percent(s->msg_length_profile[2], profile_total),
2708 			     percent(s->msg_length_profile[3], profile_total),
2709 			     percent(s->msg_length_profile[4], profile_total),
2710 			     percent(s->msg_length_profile[5], profile_total),
2711 			     percent(s->msg_length_profile[6], profile_total));
2712 
2713 	ret += tipc_snprintf(buf + ret, buf_size - ret,
2714 			     "  RX states:%u probes:%u naks:%u defs:%u"
2715 			     " dups:%u\n", s->recv_states, s->recv_probes,
2716 			     s->recv_nacks, s->deferred_recv, s->duplicates);
2717 
2718 	ret += tipc_snprintf(buf + ret, buf_size - ret,
2719 			     "  TX states:%u probes:%u naks:%u acks:%u"
2720 			     " dups:%u\n", s->sent_states, s->sent_probes,
2721 			     s->sent_nacks, s->sent_acks, s->retransmitted);
2722 
2723 	ret += tipc_snprintf(buf + ret, buf_size - ret,
2724 			     "  Congestion link:%u  Send queue"
2725 			     " max:%u avg:%u\n", s->link_congs,
2726 			     s->max_queue_sz, s->queue_sz_counts ?
2727 			     (s->accu_queue_sz / s->queue_sz_counts) : 0);
2728 
2729 	tipc_node_unlock(node);
2730 	read_unlock_bh(&tipc_net_lock);
2731 	return ret;
2732 }
2733 
2734 struct sk_buff *tipc_link_cmd_show_stats(const void *req_tlv_area, int req_tlv_space)
2735 {
2736 	struct sk_buff *buf;
2737 	struct tlv_desc *rep_tlv;
2738 	int str_len;
2739 	int pb_len;
2740 	char *pb;
2741 
2742 	if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_NAME))
2743 		return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2744 
2745 	buf = tipc_cfg_reply_alloc(TLV_SPACE(ULTRA_STRING_MAX_LEN));
2746 	if (!buf)
2747 		return NULL;
2748 
2749 	rep_tlv = (struct tlv_desc *)buf->data;
2750 	pb = TLV_DATA(rep_tlv);
2751 	pb_len = ULTRA_STRING_MAX_LEN;
2752 	str_len = tipc_link_stats((char *)TLV_DATA(req_tlv_area),
2753 				  pb, pb_len);
2754 	if (!str_len) {
2755 		kfree_skb(buf);
2756 		return tipc_cfg_reply_error_string("link not found");
2757 	}
2758 	str_len += 1;	/* for "\0" */
2759 	skb_put(buf, TLV_SPACE(str_len));
2760 	TLV_SET(rep_tlv, TIPC_TLV_ULTRA_STRING, NULL, str_len);
2761 
2762 	return buf;
2763 }
2764 
2765 /**
2766  * tipc_link_get_max_pkt - get maximum packet size to use when sending to destination
2767  * @dest: network address of destination node
2768  * @selector: used to select from set of active links
2769  *
2770  * If no active link can be found, uses default maximum packet size.
2771  */
2772 u32 tipc_link_get_max_pkt(u32 dest, u32 selector)
2773 {
2774 	struct tipc_node *n_ptr;
2775 	struct tipc_link *l_ptr;
2776 	u32 res = MAX_PKT_DEFAULT;
2777 
2778 	if (dest == tipc_own_addr)
2779 		return MAX_MSG_SIZE;
2780 
2781 	read_lock_bh(&tipc_net_lock);
2782 	n_ptr = tipc_node_find(dest);
2783 	if (n_ptr) {
2784 		tipc_node_lock(n_ptr);
2785 		l_ptr = n_ptr->active_links[selector & 1];
2786 		if (l_ptr)
2787 			res = l_ptr->max_pkt;
2788 		tipc_node_unlock(n_ptr);
2789 	}
2790 	read_unlock_bh(&tipc_net_lock);
2791 	return res;
2792 }
2793 
2794 static void link_print(struct tipc_link *l_ptr, const char *str)
2795 {
2796 	pr_info("%s Link %x<%s>:", str, l_ptr->addr, l_ptr->b_ptr->name);
2797 
2798 	if (link_working_unknown(l_ptr))
2799 		pr_cont(":WU\n");
2800 	else if (link_reset_reset(l_ptr))
2801 		pr_cont(":RR\n");
2802 	else if (link_reset_unknown(l_ptr))
2803 		pr_cont(":RU\n");
2804 	else if (link_working_working(l_ptr))
2805 		pr_cont(":WW\n");
2806 	else
2807 		pr_cont("\n");
2808 }
2809