xref: /linux/net/tipc/link.c (revision 800c5eb7b5eba6cb2a32738d763fd59f0fbcdde4)
1 /*
2  * net/tipc/link.c: TIPC link code
3  *
4  * Copyright (c) 1996-2007, Ericsson AB
5  * Copyright (c) 2004-2007, 2010-2011, Wind River Systems
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions are met:
10  *
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. Neither the names of the copyright holders nor the names of its
17  *    contributors may be used to endorse or promote products derived from
18  *    this software without specific prior written permission.
19  *
20  * Alternatively, this software may be distributed under the terms of the
21  * GNU General Public License ("GPL") version 2 as published by the Free
22  * Software Foundation.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
25  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
28  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
29  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
30  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
31  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
32  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
33  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
34  * POSSIBILITY OF SUCH DAMAGE.
35  */
36 
37 #include "core.h"
38 #include "link.h"
39 #include "port.h"
40 #include "name_distr.h"
41 #include "discover.h"
42 #include "config.h"
43 
44 
45 /*
46  * Out-of-range value for link session numbers
47  */
48 
49 #define INVALID_SESSION 0x10000
50 
51 /*
52  * Link state events:
53  */
54 
55 #define  STARTING_EVT    856384768	/* link processing trigger */
56 #define  TRAFFIC_MSG_EVT 560815u	/* rx'd ??? */
57 #define  TIMEOUT_EVT     560817u	/* link timer expired */
58 
59 /*
60  * The following two 'message types' is really just implementation
61  * data conveniently stored in the message header.
62  * They must not be considered part of the protocol
63  */
64 #define OPEN_MSG   0
65 #define CLOSED_MSG 1
66 
67 /*
68  * State value stored in 'exp_msg_count'
69  */
70 
71 #define START_CHANGEOVER 100000u
72 
73 /**
74  * struct tipc_link_name - deconstructed link name
75  * @addr_local: network address of node at this end
76  * @if_local: name of interface at this end
77  * @addr_peer: network address of node at far end
78  * @if_peer: name of interface at far end
79  */
80 
81 struct tipc_link_name {
82 	u32 addr_local;
83 	char if_local[TIPC_MAX_IF_NAME];
84 	u32 addr_peer;
85 	char if_peer[TIPC_MAX_IF_NAME];
86 };
87 
88 static void link_handle_out_of_seq_msg(struct tipc_link *l_ptr,
89 				       struct sk_buff *buf);
90 static void link_recv_proto_msg(struct tipc_link *l_ptr, struct sk_buff *buf);
91 static int  link_recv_changeover_msg(struct tipc_link **l_ptr,
92 				     struct sk_buff **buf);
93 static void link_set_supervision_props(struct tipc_link *l_ptr, u32 tolerance);
94 static int  link_send_sections_long(struct tipc_port *sender,
95 				    struct iovec const *msg_sect,
96 				    u32 num_sect, unsigned int total_len,
97 				    u32 destnode);
98 static void link_check_defragm_bufs(struct tipc_link *l_ptr);
99 static void link_state_event(struct tipc_link *l_ptr, u32 event);
100 static void link_reset_statistics(struct tipc_link *l_ptr);
101 static void link_print(struct tipc_link *l_ptr, const char *str);
102 static void link_start(struct tipc_link *l_ptr);
103 static int link_send_long_buf(struct tipc_link *l_ptr, struct sk_buff *buf);
104 
105 /*
106  *  Simple link routines
107  */
108 
109 static unsigned int align(unsigned int i)
110 {
111 	return (i + 3) & ~3u;
112 }
113 
114 static void link_init_max_pkt(struct tipc_link *l_ptr)
115 {
116 	u32 max_pkt;
117 
118 	max_pkt = (l_ptr->b_ptr->mtu & ~3);
119 	if (max_pkt > MAX_MSG_SIZE)
120 		max_pkt = MAX_MSG_SIZE;
121 
122 	l_ptr->max_pkt_target = max_pkt;
123 	if (l_ptr->max_pkt_target < MAX_PKT_DEFAULT)
124 		l_ptr->max_pkt = l_ptr->max_pkt_target;
125 	else
126 		l_ptr->max_pkt = MAX_PKT_DEFAULT;
127 
128 	l_ptr->max_pkt_probes = 0;
129 }
130 
131 static u32 link_next_sent(struct tipc_link *l_ptr)
132 {
133 	if (l_ptr->next_out)
134 		return buf_seqno(l_ptr->next_out);
135 	return mod(l_ptr->next_out_no);
136 }
137 
138 static u32 link_last_sent(struct tipc_link *l_ptr)
139 {
140 	return mod(link_next_sent(l_ptr) - 1);
141 }
142 
143 /*
144  *  Simple non-static link routines (i.e. referenced outside this file)
145  */
146 
147 int tipc_link_is_up(struct tipc_link *l_ptr)
148 {
149 	if (!l_ptr)
150 		return 0;
151 	return link_working_working(l_ptr) || link_working_unknown(l_ptr);
152 }
153 
154 int tipc_link_is_active(struct tipc_link *l_ptr)
155 {
156 	return	(l_ptr->owner->active_links[0] == l_ptr) ||
157 		(l_ptr->owner->active_links[1] == l_ptr);
158 }
159 
160 /**
161  * link_name_validate - validate & (optionally) deconstruct tipc_link name
162  * @name - ptr to link name string
163  * @name_parts - ptr to area for link name components (or NULL if not needed)
164  *
165  * Returns 1 if link name is valid, otherwise 0.
166  */
167 
168 static int link_name_validate(const char *name,
169 				struct tipc_link_name *name_parts)
170 {
171 	char name_copy[TIPC_MAX_LINK_NAME];
172 	char *addr_local;
173 	char *if_local;
174 	char *addr_peer;
175 	char *if_peer;
176 	char dummy;
177 	u32 z_local, c_local, n_local;
178 	u32 z_peer, c_peer, n_peer;
179 	u32 if_local_len;
180 	u32 if_peer_len;
181 
182 	/* copy link name & ensure length is OK */
183 
184 	name_copy[TIPC_MAX_LINK_NAME - 1] = 0;
185 	/* need above in case non-Posix strncpy() doesn't pad with nulls */
186 	strncpy(name_copy, name, TIPC_MAX_LINK_NAME);
187 	if (name_copy[TIPC_MAX_LINK_NAME - 1] != 0)
188 		return 0;
189 
190 	/* ensure all component parts of link name are present */
191 
192 	addr_local = name_copy;
193 	if_local = strchr(addr_local, ':');
194 	if (if_local == NULL)
195 		return 0;
196 	*(if_local++) = 0;
197 	addr_peer = strchr(if_local, '-');
198 	if (addr_peer == NULL)
199 		return 0;
200 	*(addr_peer++) = 0;
201 	if_local_len = addr_peer - if_local;
202 	if_peer = strchr(addr_peer, ':');
203 	if (if_peer == NULL)
204 		return 0;
205 	*(if_peer++) = 0;
206 	if_peer_len = strlen(if_peer) + 1;
207 
208 	/* validate component parts of link name */
209 
210 	if ((sscanf(addr_local, "%u.%u.%u%c",
211 		    &z_local, &c_local, &n_local, &dummy) != 3) ||
212 	    (sscanf(addr_peer, "%u.%u.%u%c",
213 		    &z_peer, &c_peer, &n_peer, &dummy) != 3) ||
214 	    (z_local > 255) || (c_local > 4095) || (n_local > 4095) ||
215 	    (z_peer  > 255) || (c_peer  > 4095) || (n_peer  > 4095) ||
216 	    (if_local_len <= 1) || (if_local_len > TIPC_MAX_IF_NAME) ||
217 	    (if_peer_len  <= 1) || (if_peer_len  > TIPC_MAX_IF_NAME) ||
218 	    (strspn(if_local, tipc_alphabet) != (if_local_len - 1)) ||
219 	    (strspn(if_peer, tipc_alphabet) != (if_peer_len - 1)))
220 		return 0;
221 
222 	/* return link name components, if necessary */
223 
224 	if (name_parts) {
225 		name_parts->addr_local = tipc_addr(z_local, c_local, n_local);
226 		strcpy(name_parts->if_local, if_local);
227 		name_parts->addr_peer = tipc_addr(z_peer, c_peer, n_peer);
228 		strcpy(name_parts->if_peer, if_peer);
229 	}
230 	return 1;
231 }
232 
233 /**
234  * link_timeout - handle expiration of link timer
235  * @l_ptr: pointer to link
236  *
237  * This routine must not grab "tipc_net_lock" to avoid a potential deadlock conflict
238  * with tipc_link_delete().  (There is no risk that the node will be deleted by
239  * another thread because tipc_link_delete() always cancels the link timer before
240  * tipc_node_delete() is called.)
241  */
242 
243 static void link_timeout(struct tipc_link *l_ptr)
244 {
245 	tipc_node_lock(l_ptr->owner);
246 
247 	/* update counters used in statistical profiling of send traffic */
248 
249 	l_ptr->stats.accu_queue_sz += l_ptr->out_queue_size;
250 	l_ptr->stats.queue_sz_counts++;
251 
252 	if (l_ptr->first_out) {
253 		struct tipc_msg *msg = buf_msg(l_ptr->first_out);
254 		u32 length = msg_size(msg);
255 
256 		if ((msg_user(msg) == MSG_FRAGMENTER) &&
257 		    (msg_type(msg) == FIRST_FRAGMENT)) {
258 			length = msg_size(msg_get_wrapped(msg));
259 		}
260 		if (length) {
261 			l_ptr->stats.msg_lengths_total += length;
262 			l_ptr->stats.msg_length_counts++;
263 			if (length <= 64)
264 				l_ptr->stats.msg_length_profile[0]++;
265 			else if (length <= 256)
266 				l_ptr->stats.msg_length_profile[1]++;
267 			else if (length <= 1024)
268 				l_ptr->stats.msg_length_profile[2]++;
269 			else if (length <= 4096)
270 				l_ptr->stats.msg_length_profile[3]++;
271 			else if (length <= 16384)
272 				l_ptr->stats.msg_length_profile[4]++;
273 			else if (length <= 32768)
274 				l_ptr->stats.msg_length_profile[5]++;
275 			else
276 				l_ptr->stats.msg_length_profile[6]++;
277 		}
278 	}
279 
280 	/* do all other link processing performed on a periodic basis */
281 
282 	link_check_defragm_bufs(l_ptr);
283 
284 	link_state_event(l_ptr, TIMEOUT_EVT);
285 
286 	if (l_ptr->next_out)
287 		tipc_link_push_queue(l_ptr);
288 
289 	tipc_node_unlock(l_ptr->owner);
290 }
291 
292 static void link_set_timer(struct tipc_link *l_ptr, u32 time)
293 {
294 	k_start_timer(&l_ptr->timer, time);
295 }
296 
297 /**
298  * tipc_link_create - create a new link
299  * @n_ptr: pointer to associated node
300  * @b_ptr: pointer to associated bearer
301  * @media_addr: media address to use when sending messages over link
302  *
303  * Returns pointer to link.
304  */
305 
306 struct tipc_link *tipc_link_create(struct tipc_node *n_ptr,
307 			      struct tipc_bearer *b_ptr,
308 			      const struct tipc_media_addr *media_addr)
309 {
310 	struct tipc_link *l_ptr;
311 	struct tipc_msg *msg;
312 	char *if_name;
313 	char addr_string[16];
314 	u32 peer = n_ptr->addr;
315 
316 	if (n_ptr->link_cnt >= 2) {
317 		tipc_addr_string_fill(addr_string, n_ptr->addr);
318 		err("Attempt to establish third link to %s\n", addr_string);
319 		return NULL;
320 	}
321 
322 	if (n_ptr->links[b_ptr->identity]) {
323 		tipc_addr_string_fill(addr_string, n_ptr->addr);
324 		err("Attempt to establish second link on <%s> to %s\n",
325 		    b_ptr->name, addr_string);
326 		return NULL;
327 	}
328 
329 	l_ptr = kzalloc(sizeof(*l_ptr), GFP_ATOMIC);
330 	if (!l_ptr) {
331 		warn("Link creation failed, no memory\n");
332 		return NULL;
333 	}
334 
335 	l_ptr->addr = peer;
336 	if_name = strchr(b_ptr->name, ':') + 1;
337 	sprintf(l_ptr->name, "%u.%u.%u:%s-%u.%u.%u:unknown",
338 		tipc_zone(tipc_own_addr), tipc_cluster(tipc_own_addr),
339 		tipc_node(tipc_own_addr),
340 		if_name,
341 		tipc_zone(peer), tipc_cluster(peer), tipc_node(peer));
342 		/* note: peer i/f name is updated by reset/activate message */
343 	memcpy(&l_ptr->media_addr, media_addr, sizeof(*media_addr));
344 	l_ptr->owner = n_ptr;
345 	l_ptr->checkpoint = 1;
346 	l_ptr->peer_session = INVALID_SESSION;
347 	l_ptr->b_ptr = b_ptr;
348 	link_set_supervision_props(l_ptr, b_ptr->tolerance);
349 	l_ptr->state = RESET_UNKNOWN;
350 
351 	l_ptr->pmsg = (struct tipc_msg *)&l_ptr->proto_msg;
352 	msg = l_ptr->pmsg;
353 	tipc_msg_init(msg, LINK_PROTOCOL, RESET_MSG, INT_H_SIZE, l_ptr->addr);
354 	msg_set_size(msg, sizeof(l_ptr->proto_msg));
355 	msg_set_session(msg, (tipc_random & 0xffff));
356 	msg_set_bearer_id(msg, b_ptr->identity);
357 	strcpy((char *)msg_data(msg), if_name);
358 
359 	l_ptr->priority = b_ptr->priority;
360 	tipc_link_set_queue_limits(l_ptr, b_ptr->window);
361 
362 	link_init_max_pkt(l_ptr);
363 
364 	l_ptr->next_out_no = 1;
365 	INIT_LIST_HEAD(&l_ptr->waiting_ports);
366 
367 	link_reset_statistics(l_ptr);
368 
369 	tipc_node_attach_link(n_ptr, l_ptr);
370 
371 	k_init_timer(&l_ptr->timer, (Handler)link_timeout, (unsigned long)l_ptr);
372 	list_add_tail(&l_ptr->link_list, &b_ptr->links);
373 	tipc_k_signal((Handler)link_start, (unsigned long)l_ptr);
374 
375 	return l_ptr;
376 }
377 
378 /**
379  * tipc_link_delete - delete a link
380  * @l_ptr: pointer to link
381  *
382  * Note: 'tipc_net_lock' is write_locked, bearer is locked.
383  * This routine must not grab the node lock until after link timer cancellation
384  * to avoid a potential deadlock situation.
385  */
386 
387 void tipc_link_delete(struct tipc_link *l_ptr)
388 {
389 	if (!l_ptr) {
390 		err("Attempt to delete non-existent link\n");
391 		return;
392 	}
393 
394 	k_cancel_timer(&l_ptr->timer);
395 
396 	tipc_node_lock(l_ptr->owner);
397 	tipc_link_reset(l_ptr);
398 	tipc_node_detach_link(l_ptr->owner, l_ptr);
399 	tipc_link_stop(l_ptr);
400 	list_del_init(&l_ptr->link_list);
401 	tipc_node_unlock(l_ptr->owner);
402 	k_term_timer(&l_ptr->timer);
403 	kfree(l_ptr);
404 }
405 
406 static void link_start(struct tipc_link *l_ptr)
407 {
408 	tipc_node_lock(l_ptr->owner);
409 	link_state_event(l_ptr, STARTING_EVT);
410 	tipc_node_unlock(l_ptr->owner);
411 }
412 
413 /**
414  * link_schedule_port - schedule port for deferred sending
415  * @l_ptr: pointer to link
416  * @origport: reference to sending port
417  * @sz: amount of data to be sent
418  *
419  * Schedules port for renewed sending of messages after link congestion
420  * has abated.
421  */
422 
423 static int link_schedule_port(struct tipc_link *l_ptr, u32 origport, u32 sz)
424 {
425 	struct tipc_port *p_ptr;
426 
427 	spin_lock_bh(&tipc_port_list_lock);
428 	p_ptr = tipc_port_lock(origport);
429 	if (p_ptr) {
430 		if (!p_ptr->wakeup)
431 			goto exit;
432 		if (!list_empty(&p_ptr->wait_list))
433 			goto exit;
434 		p_ptr->congested = 1;
435 		p_ptr->waiting_pkts = 1 + ((sz - 1) / l_ptr->max_pkt);
436 		list_add_tail(&p_ptr->wait_list, &l_ptr->waiting_ports);
437 		l_ptr->stats.link_congs++;
438 exit:
439 		tipc_port_unlock(p_ptr);
440 	}
441 	spin_unlock_bh(&tipc_port_list_lock);
442 	return -ELINKCONG;
443 }
444 
445 void tipc_link_wakeup_ports(struct tipc_link *l_ptr, int all)
446 {
447 	struct tipc_port *p_ptr;
448 	struct tipc_port *temp_p_ptr;
449 	int win = l_ptr->queue_limit[0] - l_ptr->out_queue_size;
450 
451 	if (all)
452 		win = 100000;
453 	if (win <= 0)
454 		return;
455 	if (!spin_trylock_bh(&tipc_port_list_lock))
456 		return;
457 	if (link_congested(l_ptr))
458 		goto exit;
459 	list_for_each_entry_safe(p_ptr, temp_p_ptr, &l_ptr->waiting_ports,
460 				 wait_list) {
461 		if (win <= 0)
462 			break;
463 		list_del_init(&p_ptr->wait_list);
464 		spin_lock_bh(p_ptr->lock);
465 		p_ptr->congested = 0;
466 		p_ptr->wakeup(p_ptr);
467 		win -= p_ptr->waiting_pkts;
468 		spin_unlock_bh(p_ptr->lock);
469 	}
470 
471 exit:
472 	spin_unlock_bh(&tipc_port_list_lock);
473 }
474 
475 /**
476  * link_release_outqueue - purge link's outbound message queue
477  * @l_ptr: pointer to link
478  */
479 
480 static void link_release_outqueue(struct tipc_link *l_ptr)
481 {
482 	struct sk_buff *buf = l_ptr->first_out;
483 	struct sk_buff *next;
484 
485 	while (buf) {
486 		next = buf->next;
487 		buf_discard(buf);
488 		buf = next;
489 	}
490 	l_ptr->first_out = NULL;
491 	l_ptr->out_queue_size = 0;
492 }
493 
494 /**
495  * tipc_link_reset_fragments - purge link's inbound message fragments queue
496  * @l_ptr: pointer to link
497  */
498 
499 void tipc_link_reset_fragments(struct tipc_link *l_ptr)
500 {
501 	struct sk_buff *buf = l_ptr->defragm_buf;
502 	struct sk_buff *next;
503 
504 	while (buf) {
505 		next = buf->next;
506 		buf_discard(buf);
507 		buf = next;
508 	}
509 	l_ptr->defragm_buf = NULL;
510 }
511 
512 /**
513  * tipc_link_stop - purge all inbound and outbound messages associated with link
514  * @l_ptr: pointer to link
515  */
516 
517 void tipc_link_stop(struct tipc_link *l_ptr)
518 {
519 	struct sk_buff *buf;
520 	struct sk_buff *next;
521 
522 	buf = l_ptr->oldest_deferred_in;
523 	while (buf) {
524 		next = buf->next;
525 		buf_discard(buf);
526 		buf = next;
527 	}
528 
529 	buf = l_ptr->first_out;
530 	while (buf) {
531 		next = buf->next;
532 		buf_discard(buf);
533 		buf = next;
534 	}
535 
536 	tipc_link_reset_fragments(l_ptr);
537 
538 	buf_discard(l_ptr->proto_msg_queue);
539 	l_ptr->proto_msg_queue = NULL;
540 }
541 
542 void tipc_link_reset(struct tipc_link *l_ptr)
543 {
544 	struct sk_buff *buf;
545 	u32 prev_state = l_ptr->state;
546 	u32 checkpoint = l_ptr->next_in_no;
547 	int was_active_link = tipc_link_is_active(l_ptr);
548 
549 	msg_set_session(l_ptr->pmsg, ((msg_session(l_ptr->pmsg) + 1) & 0xffff));
550 
551 	/* Link is down, accept any session */
552 	l_ptr->peer_session = INVALID_SESSION;
553 
554 	/* Prepare for max packet size negotiation */
555 	link_init_max_pkt(l_ptr);
556 
557 	l_ptr->state = RESET_UNKNOWN;
558 
559 	if ((prev_state == RESET_UNKNOWN) || (prev_state == RESET_RESET))
560 		return;
561 
562 	tipc_node_link_down(l_ptr->owner, l_ptr);
563 	tipc_bearer_remove_dest(l_ptr->b_ptr, l_ptr->addr);
564 
565 	if (was_active_link && tipc_node_active_links(l_ptr->owner) &&
566 	    l_ptr->owner->permit_changeover) {
567 		l_ptr->reset_checkpoint = checkpoint;
568 		l_ptr->exp_msg_count = START_CHANGEOVER;
569 	}
570 
571 	/* Clean up all queues: */
572 
573 	link_release_outqueue(l_ptr);
574 	buf_discard(l_ptr->proto_msg_queue);
575 	l_ptr->proto_msg_queue = NULL;
576 	buf = l_ptr->oldest_deferred_in;
577 	while (buf) {
578 		struct sk_buff *next = buf->next;
579 		buf_discard(buf);
580 		buf = next;
581 	}
582 	if (!list_empty(&l_ptr->waiting_ports))
583 		tipc_link_wakeup_ports(l_ptr, 1);
584 
585 	l_ptr->retransm_queue_head = 0;
586 	l_ptr->retransm_queue_size = 0;
587 	l_ptr->last_out = NULL;
588 	l_ptr->first_out = NULL;
589 	l_ptr->next_out = NULL;
590 	l_ptr->unacked_window = 0;
591 	l_ptr->checkpoint = 1;
592 	l_ptr->next_out_no = 1;
593 	l_ptr->deferred_inqueue_sz = 0;
594 	l_ptr->oldest_deferred_in = NULL;
595 	l_ptr->newest_deferred_in = NULL;
596 	l_ptr->fsm_msg_cnt = 0;
597 	l_ptr->stale_count = 0;
598 	link_reset_statistics(l_ptr);
599 }
600 
601 
602 static void link_activate(struct tipc_link *l_ptr)
603 {
604 	l_ptr->next_in_no = l_ptr->stats.recv_info = 1;
605 	tipc_node_link_up(l_ptr->owner, l_ptr);
606 	tipc_bearer_add_dest(l_ptr->b_ptr, l_ptr->addr);
607 }
608 
609 /**
610  * link_state_event - link finite state machine
611  * @l_ptr: pointer to link
612  * @event: state machine event to process
613  */
614 
615 static void link_state_event(struct tipc_link *l_ptr, unsigned event)
616 {
617 	struct tipc_link *other;
618 	u32 cont_intv = l_ptr->continuity_interval;
619 
620 	if (!l_ptr->started && (event != STARTING_EVT))
621 		return;		/* Not yet. */
622 
623 	if (link_blocked(l_ptr)) {
624 		if (event == TIMEOUT_EVT)
625 			link_set_timer(l_ptr, cont_intv);
626 		return;	  /* Changeover going on */
627 	}
628 
629 	switch (l_ptr->state) {
630 	case WORKING_WORKING:
631 		switch (event) {
632 		case TRAFFIC_MSG_EVT:
633 		case ACTIVATE_MSG:
634 			break;
635 		case TIMEOUT_EVT:
636 			if (l_ptr->next_in_no != l_ptr->checkpoint) {
637 				l_ptr->checkpoint = l_ptr->next_in_no;
638 				if (tipc_bclink_acks_missing(l_ptr->owner)) {
639 					tipc_link_send_proto_msg(l_ptr, STATE_MSG,
640 								 0, 0, 0, 0, 0);
641 					l_ptr->fsm_msg_cnt++;
642 				} else if (l_ptr->max_pkt < l_ptr->max_pkt_target) {
643 					tipc_link_send_proto_msg(l_ptr, STATE_MSG,
644 								 1, 0, 0, 0, 0);
645 					l_ptr->fsm_msg_cnt++;
646 				}
647 				link_set_timer(l_ptr, cont_intv);
648 				break;
649 			}
650 			l_ptr->state = WORKING_UNKNOWN;
651 			l_ptr->fsm_msg_cnt = 0;
652 			tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
653 			l_ptr->fsm_msg_cnt++;
654 			link_set_timer(l_ptr, cont_intv / 4);
655 			break;
656 		case RESET_MSG:
657 			info("Resetting link <%s>, requested by peer\n",
658 			     l_ptr->name);
659 			tipc_link_reset(l_ptr);
660 			l_ptr->state = RESET_RESET;
661 			l_ptr->fsm_msg_cnt = 0;
662 			tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
663 			l_ptr->fsm_msg_cnt++;
664 			link_set_timer(l_ptr, cont_intv);
665 			break;
666 		default:
667 			err("Unknown link event %u in WW state\n", event);
668 		}
669 		break;
670 	case WORKING_UNKNOWN:
671 		switch (event) {
672 		case TRAFFIC_MSG_EVT:
673 		case ACTIVATE_MSG:
674 			l_ptr->state = WORKING_WORKING;
675 			l_ptr->fsm_msg_cnt = 0;
676 			link_set_timer(l_ptr, cont_intv);
677 			break;
678 		case RESET_MSG:
679 			info("Resetting link <%s>, requested by peer "
680 			     "while probing\n", l_ptr->name);
681 			tipc_link_reset(l_ptr);
682 			l_ptr->state = RESET_RESET;
683 			l_ptr->fsm_msg_cnt = 0;
684 			tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
685 			l_ptr->fsm_msg_cnt++;
686 			link_set_timer(l_ptr, cont_intv);
687 			break;
688 		case TIMEOUT_EVT:
689 			if (l_ptr->next_in_no != l_ptr->checkpoint) {
690 				l_ptr->state = WORKING_WORKING;
691 				l_ptr->fsm_msg_cnt = 0;
692 				l_ptr->checkpoint = l_ptr->next_in_no;
693 				if (tipc_bclink_acks_missing(l_ptr->owner)) {
694 					tipc_link_send_proto_msg(l_ptr, STATE_MSG,
695 								 0, 0, 0, 0, 0);
696 					l_ptr->fsm_msg_cnt++;
697 				}
698 				link_set_timer(l_ptr, cont_intv);
699 			} else if (l_ptr->fsm_msg_cnt < l_ptr->abort_limit) {
700 				tipc_link_send_proto_msg(l_ptr, STATE_MSG,
701 							 1, 0, 0, 0, 0);
702 				l_ptr->fsm_msg_cnt++;
703 				link_set_timer(l_ptr, cont_intv / 4);
704 			} else {	/* Link has failed */
705 				warn("Resetting link <%s>, peer not responding\n",
706 				     l_ptr->name);
707 				tipc_link_reset(l_ptr);
708 				l_ptr->state = RESET_UNKNOWN;
709 				l_ptr->fsm_msg_cnt = 0;
710 				tipc_link_send_proto_msg(l_ptr, RESET_MSG,
711 							 0, 0, 0, 0, 0);
712 				l_ptr->fsm_msg_cnt++;
713 				link_set_timer(l_ptr, cont_intv);
714 			}
715 			break;
716 		default:
717 			err("Unknown link event %u in WU state\n", event);
718 		}
719 		break;
720 	case RESET_UNKNOWN:
721 		switch (event) {
722 		case TRAFFIC_MSG_EVT:
723 			break;
724 		case ACTIVATE_MSG:
725 			other = l_ptr->owner->active_links[0];
726 			if (other && link_working_unknown(other))
727 				break;
728 			l_ptr->state = WORKING_WORKING;
729 			l_ptr->fsm_msg_cnt = 0;
730 			link_activate(l_ptr);
731 			tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
732 			l_ptr->fsm_msg_cnt++;
733 			link_set_timer(l_ptr, cont_intv);
734 			break;
735 		case RESET_MSG:
736 			l_ptr->state = RESET_RESET;
737 			l_ptr->fsm_msg_cnt = 0;
738 			tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 1, 0, 0, 0, 0);
739 			l_ptr->fsm_msg_cnt++;
740 			link_set_timer(l_ptr, cont_intv);
741 			break;
742 		case STARTING_EVT:
743 			l_ptr->started = 1;
744 			/* fall through */
745 		case TIMEOUT_EVT:
746 			tipc_link_send_proto_msg(l_ptr, RESET_MSG, 0, 0, 0, 0, 0);
747 			l_ptr->fsm_msg_cnt++;
748 			link_set_timer(l_ptr, cont_intv);
749 			break;
750 		default:
751 			err("Unknown link event %u in RU state\n", event);
752 		}
753 		break;
754 	case RESET_RESET:
755 		switch (event) {
756 		case TRAFFIC_MSG_EVT:
757 		case ACTIVATE_MSG:
758 			other = l_ptr->owner->active_links[0];
759 			if (other && link_working_unknown(other))
760 				break;
761 			l_ptr->state = WORKING_WORKING;
762 			l_ptr->fsm_msg_cnt = 0;
763 			link_activate(l_ptr);
764 			tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
765 			l_ptr->fsm_msg_cnt++;
766 			link_set_timer(l_ptr, cont_intv);
767 			break;
768 		case RESET_MSG:
769 			break;
770 		case TIMEOUT_EVT:
771 			tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
772 			l_ptr->fsm_msg_cnt++;
773 			link_set_timer(l_ptr, cont_intv);
774 			break;
775 		default:
776 			err("Unknown link event %u in RR state\n", event);
777 		}
778 		break;
779 	default:
780 		err("Unknown link state %u/%u\n", l_ptr->state, event);
781 	}
782 }
783 
784 /*
785  * link_bundle_buf(): Append contents of a buffer to
786  * the tail of an existing one.
787  */
788 
789 static int link_bundle_buf(struct tipc_link *l_ptr,
790 			   struct sk_buff *bundler,
791 			   struct sk_buff *buf)
792 {
793 	struct tipc_msg *bundler_msg = buf_msg(bundler);
794 	struct tipc_msg *msg = buf_msg(buf);
795 	u32 size = msg_size(msg);
796 	u32 bundle_size = msg_size(bundler_msg);
797 	u32 to_pos = align(bundle_size);
798 	u32 pad = to_pos - bundle_size;
799 
800 	if (msg_user(bundler_msg) != MSG_BUNDLER)
801 		return 0;
802 	if (msg_type(bundler_msg) != OPEN_MSG)
803 		return 0;
804 	if (skb_tailroom(bundler) < (pad + size))
805 		return 0;
806 	if (l_ptr->max_pkt < (to_pos + size))
807 		return 0;
808 
809 	skb_put(bundler, pad + size);
810 	skb_copy_to_linear_data_offset(bundler, to_pos, buf->data, size);
811 	msg_set_size(bundler_msg, to_pos + size);
812 	msg_set_msgcnt(bundler_msg, msg_msgcnt(bundler_msg) + 1);
813 	buf_discard(buf);
814 	l_ptr->stats.sent_bundled++;
815 	return 1;
816 }
817 
818 static void link_add_to_outqueue(struct tipc_link *l_ptr,
819 				 struct sk_buff *buf,
820 				 struct tipc_msg *msg)
821 {
822 	u32 ack = mod(l_ptr->next_in_no - 1);
823 	u32 seqno = mod(l_ptr->next_out_no++);
824 
825 	msg_set_word(msg, 2, ((ack << 16) | seqno));
826 	msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
827 	buf->next = NULL;
828 	if (l_ptr->first_out) {
829 		l_ptr->last_out->next = buf;
830 		l_ptr->last_out = buf;
831 	} else
832 		l_ptr->first_out = l_ptr->last_out = buf;
833 
834 	l_ptr->out_queue_size++;
835 	if (l_ptr->out_queue_size > l_ptr->stats.max_queue_sz)
836 		l_ptr->stats.max_queue_sz = l_ptr->out_queue_size;
837 }
838 
839 static void link_add_chain_to_outqueue(struct tipc_link *l_ptr,
840 				       struct sk_buff *buf_chain,
841 				       u32 long_msgno)
842 {
843 	struct sk_buff *buf;
844 	struct tipc_msg *msg;
845 
846 	if (!l_ptr->next_out)
847 		l_ptr->next_out = buf_chain;
848 	while (buf_chain) {
849 		buf = buf_chain;
850 		buf_chain = buf_chain->next;
851 
852 		msg = buf_msg(buf);
853 		msg_set_long_msgno(msg, long_msgno);
854 		link_add_to_outqueue(l_ptr, buf, msg);
855 	}
856 }
857 
858 /*
859  * tipc_link_send_buf() is the 'full path' for messages, called from
860  * inside TIPC when the 'fast path' in tipc_send_buf
861  * has failed, and from link_send()
862  */
863 
864 int tipc_link_send_buf(struct tipc_link *l_ptr, struct sk_buff *buf)
865 {
866 	struct tipc_msg *msg = buf_msg(buf);
867 	u32 size = msg_size(msg);
868 	u32 dsz = msg_data_sz(msg);
869 	u32 queue_size = l_ptr->out_queue_size;
870 	u32 imp = tipc_msg_tot_importance(msg);
871 	u32 queue_limit = l_ptr->queue_limit[imp];
872 	u32 max_packet = l_ptr->max_pkt;
873 
874 	msg_set_prevnode(msg, tipc_own_addr);	/* If routed message */
875 
876 	/* Match msg importance against queue limits: */
877 
878 	if (unlikely(queue_size >= queue_limit)) {
879 		if (imp <= TIPC_CRITICAL_IMPORTANCE) {
880 			link_schedule_port(l_ptr, msg_origport(msg), size);
881 			buf_discard(buf);
882 			return -ELINKCONG;
883 		}
884 		buf_discard(buf);
885 		if (imp > CONN_MANAGER) {
886 			warn("Resetting link <%s>, send queue full", l_ptr->name);
887 			tipc_link_reset(l_ptr);
888 		}
889 		return dsz;
890 	}
891 
892 	/* Fragmentation needed ? */
893 
894 	if (size > max_packet)
895 		return link_send_long_buf(l_ptr, buf);
896 
897 	/* Packet can be queued or sent: */
898 
899 	if (likely(!tipc_bearer_congested(l_ptr->b_ptr, l_ptr) &&
900 		   !link_congested(l_ptr))) {
901 		link_add_to_outqueue(l_ptr, buf, msg);
902 
903 		if (likely(tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr))) {
904 			l_ptr->unacked_window = 0;
905 		} else {
906 			tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
907 			l_ptr->stats.bearer_congs++;
908 			l_ptr->next_out = buf;
909 		}
910 		return dsz;
911 	}
912 	/* Congestion: can message be bundled ?: */
913 
914 	if ((msg_user(msg) != CHANGEOVER_PROTOCOL) &&
915 	    (msg_user(msg) != MSG_FRAGMENTER)) {
916 
917 		/* Try adding message to an existing bundle */
918 
919 		if (l_ptr->next_out &&
920 		    link_bundle_buf(l_ptr, l_ptr->last_out, buf)) {
921 			tipc_bearer_resolve_congestion(l_ptr->b_ptr, l_ptr);
922 			return dsz;
923 		}
924 
925 		/* Try creating a new bundle */
926 
927 		if (size <= max_packet * 2 / 3) {
928 			struct sk_buff *bundler = tipc_buf_acquire(max_packet);
929 			struct tipc_msg bundler_hdr;
930 
931 			if (bundler) {
932 				tipc_msg_init(&bundler_hdr, MSG_BUNDLER, OPEN_MSG,
933 					 INT_H_SIZE, l_ptr->addr);
934 				skb_copy_to_linear_data(bundler, &bundler_hdr,
935 							INT_H_SIZE);
936 				skb_trim(bundler, INT_H_SIZE);
937 				link_bundle_buf(l_ptr, bundler, buf);
938 				buf = bundler;
939 				msg = buf_msg(buf);
940 				l_ptr->stats.sent_bundles++;
941 			}
942 		}
943 	}
944 	if (!l_ptr->next_out)
945 		l_ptr->next_out = buf;
946 	link_add_to_outqueue(l_ptr, buf, msg);
947 	tipc_bearer_resolve_congestion(l_ptr->b_ptr, l_ptr);
948 	return dsz;
949 }
950 
951 /*
952  * tipc_link_send(): same as tipc_link_send_buf(), but the link to use has
953  * not been selected yet, and the the owner node is not locked
954  * Called by TIPC internal users, e.g. the name distributor
955  */
956 
957 int tipc_link_send(struct sk_buff *buf, u32 dest, u32 selector)
958 {
959 	struct tipc_link *l_ptr;
960 	struct tipc_node *n_ptr;
961 	int res = -ELINKCONG;
962 
963 	read_lock_bh(&tipc_net_lock);
964 	n_ptr = tipc_node_find(dest);
965 	if (n_ptr) {
966 		tipc_node_lock(n_ptr);
967 		l_ptr = n_ptr->active_links[selector & 1];
968 		if (l_ptr)
969 			res = tipc_link_send_buf(l_ptr, buf);
970 		else
971 			buf_discard(buf);
972 		tipc_node_unlock(n_ptr);
973 	} else {
974 		buf_discard(buf);
975 	}
976 	read_unlock_bh(&tipc_net_lock);
977 	return res;
978 }
979 
980 /*
981  * tipc_link_send_names - send name table entries to new neighbor
982  *
983  * Send routine for bulk delivery of name table messages when contact
984  * with a new neighbor occurs. No link congestion checking is performed
985  * because name table messages *must* be delivered. The messages must be
986  * small enough not to require fragmentation.
987  * Called without any locks held.
988  */
989 
990 void tipc_link_send_names(struct list_head *message_list, u32 dest)
991 {
992 	struct tipc_node *n_ptr;
993 	struct tipc_link *l_ptr;
994 	struct sk_buff *buf;
995 	struct sk_buff *temp_buf;
996 
997 	if (list_empty(message_list))
998 		return;
999 
1000 	read_lock_bh(&tipc_net_lock);
1001 	n_ptr = tipc_node_find(dest);
1002 	if (n_ptr) {
1003 		tipc_node_lock(n_ptr);
1004 		l_ptr = n_ptr->active_links[0];
1005 		if (l_ptr) {
1006 			/* convert circular list to linear list */
1007 			((struct sk_buff *)message_list->prev)->next = NULL;
1008 			link_add_chain_to_outqueue(l_ptr,
1009 				(struct sk_buff *)message_list->next, 0);
1010 			tipc_link_push_queue(l_ptr);
1011 			INIT_LIST_HEAD(message_list);
1012 		}
1013 		tipc_node_unlock(n_ptr);
1014 	}
1015 	read_unlock_bh(&tipc_net_lock);
1016 
1017 	/* discard the messages if they couldn't be sent */
1018 
1019 	list_for_each_safe(buf, temp_buf, ((struct sk_buff *)message_list)) {
1020 		list_del((struct list_head *)buf);
1021 		buf_discard(buf);
1022 	}
1023 }
1024 
1025 /*
1026  * link_send_buf_fast: Entry for data messages where the
1027  * destination link is known and the header is complete,
1028  * inclusive total message length. Very time critical.
1029  * Link is locked. Returns user data length.
1030  */
1031 
1032 static int link_send_buf_fast(struct tipc_link *l_ptr, struct sk_buff *buf,
1033 			      u32 *used_max_pkt)
1034 {
1035 	struct tipc_msg *msg = buf_msg(buf);
1036 	int res = msg_data_sz(msg);
1037 
1038 	if (likely(!link_congested(l_ptr))) {
1039 		if (likely(msg_size(msg) <= l_ptr->max_pkt)) {
1040 			if (likely(list_empty(&l_ptr->b_ptr->cong_links))) {
1041 				link_add_to_outqueue(l_ptr, buf, msg);
1042 				if (likely(tipc_bearer_send(l_ptr->b_ptr, buf,
1043 							    &l_ptr->media_addr))) {
1044 					l_ptr->unacked_window = 0;
1045 					return res;
1046 				}
1047 				tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
1048 				l_ptr->stats.bearer_congs++;
1049 				l_ptr->next_out = buf;
1050 				return res;
1051 			}
1052 		} else
1053 			*used_max_pkt = l_ptr->max_pkt;
1054 	}
1055 	return tipc_link_send_buf(l_ptr, buf);  /* All other cases */
1056 }
1057 
1058 /*
1059  * tipc_send_buf_fast: Entry for data messages where the
1060  * destination node is known and the header is complete,
1061  * inclusive total message length.
1062  * Returns user data length.
1063  */
1064 int tipc_send_buf_fast(struct sk_buff *buf, u32 destnode)
1065 {
1066 	struct tipc_link *l_ptr;
1067 	struct tipc_node *n_ptr;
1068 	int res;
1069 	u32 selector = msg_origport(buf_msg(buf)) & 1;
1070 	u32 dummy;
1071 
1072 	read_lock_bh(&tipc_net_lock);
1073 	n_ptr = tipc_node_find(destnode);
1074 	if (likely(n_ptr)) {
1075 		tipc_node_lock(n_ptr);
1076 		l_ptr = n_ptr->active_links[selector];
1077 		if (likely(l_ptr)) {
1078 			res = link_send_buf_fast(l_ptr, buf, &dummy);
1079 			tipc_node_unlock(n_ptr);
1080 			read_unlock_bh(&tipc_net_lock);
1081 			return res;
1082 		}
1083 		tipc_node_unlock(n_ptr);
1084 	}
1085 	read_unlock_bh(&tipc_net_lock);
1086 	res = msg_data_sz(buf_msg(buf));
1087 	tipc_reject_msg(buf, TIPC_ERR_NO_NODE);
1088 	return res;
1089 }
1090 
1091 
1092 /*
1093  * tipc_link_send_sections_fast: Entry for messages where the
1094  * destination processor is known and the header is complete,
1095  * except for total message length.
1096  * Returns user data length or errno.
1097  */
1098 int tipc_link_send_sections_fast(struct tipc_port *sender,
1099 				 struct iovec const *msg_sect,
1100 				 const u32 num_sect,
1101 				 unsigned int total_len,
1102 				 u32 destaddr)
1103 {
1104 	struct tipc_msg *hdr = &sender->phdr;
1105 	struct tipc_link *l_ptr;
1106 	struct sk_buff *buf;
1107 	struct tipc_node *node;
1108 	int res;
1109 	u32 selector = msg_origport(hdr) & 1;
1110 
1111 again:
1112 	/*
1113 	 * Try building message using port's max_pkt hint.
1114 	 * (Must not hold any locks while building message.)
1115 	 */
1116 
1117 	res = tipc_msg_build(hdr, msg_sect, num_sect, total_len,
1118 			     sender->max_pkt, !sender->user_port, &buf);
1119 
1120 	read_lock_bh(&tipc_net_lock);
1121 	node = tipc_node_find(destaddr);
1122 	if (likely(node)) {
1123 		tipc_node_lock(node);
1124 		l_ptr = node->active_links[selector];
1125 		if (likely(l_ptr)) {
1126 			if (likely(buf)) {
1127 				res = link_send_buf_fast(l_ptr, buf,
1128 							 &sender->max_pkt);
1129 exit:
1130 				tipc_node_unlock(node);
1131 				read_unlock_bh(&tipc_net_lock);
1132 				return res;
1133 			}
1134 
1135 			/* Exit if build request was invalid */
1136 
1137 			if (unlikely(res < 0))
1138 				goto exit;
1139 
1140 			/* Exit if link (or bearer) is congested */
1141 
1142 			if (link_congested(l_ptr) ||
1143 			    !list_empty(&l_ptr->b_ptr->cong_links)) {
1144 				res = link_schedule_port(l_ptr,
1145 							 sender->ref, res);
1146 				goto exit;
1147 			}
1148 
1149 			/*
1150 			 * Message size exceeds max_pkt hint; update hint,
1151 			 * then re-try fast path or fragment the message
1152 			 */
1153 
1154 			sender->max_pkt = l_ptr->max_pkt;
1155 			tipc_node_unlock(node);
1156 			read_unlock_bh(&tipc_net_lock);
1157 
1158 
1159 			if ((msg_hdr_sz(hdr) + res) <= sender->max_pkt)
1160 				goto again;
1161 
1162 			return link_send_sections_long(sender, msg_sect,
1163 						       num_sect, total_len,
1164 						       destaddr);
1165 		}
1166 		tipc_node_unlock(node);
1167 	}
1168 	read_unlock_bh(&tipc_net_lock);
1169 
1170 	/* Couldn't find a link to the destination node */
1171 
1172 	if (buf)
1173 		return tipc_reject_msg(buf, TIPC_ERR_NO_NODE);
1174 	if (res >= 0)
1175 		return tipc_port_reject_sections(sender, hdr, msg_sect, num_sect,
1176 						 total_len, TIPC_ERR_NO_NODE);
1177 	return res;
1178 }
1179 
1180 /*
1181  * link_send_sections_long(): Entry for long messages where the
1182  * destination node is known and the header is complete,
1183  * inclusive total message length.
1184  * Link and bearer congestion status have been checked to be ok,
1185  * and are ignored if they change.
1186  *
1187  * Note that fragments do not use the full link MTU so that they won't have
1188  * to undergo refragmentation if link changeover causes them to be sent
1189  * over another link with an additional tunnel header added as prefix.
1190  * (Refragmentation will still occur if the other link has a smaller MTU.)
1191  *
1192  * Returns user data length or errno.
1193  */
1194 static int link_send_sections_long(struct tipc_port *sender,
1195 				   struct iovec const *msg_sect,
1196 				   u32 num_sect,
1197 				   unsigned int total_len,
1198 				   u32 destaddr)
1199 {
1200 	struct tipc_link *l_ptr;
1201 	struct tipc_node *node;
1202 	struct tipc_msg *hdr = &sender->phdr;
1203 	u32 dsz = total_len;
1204 	u32 max_pkt, fragm_sz, rest;
1205 	struct tipc_msg fragm_hdr;
1206 	struct sk_buff *buf, *buf_chain, *prev;
1207 	u32 fragm_crs, fragm_rest, hsz, sect_rest;
1208 	const unchar *sect_crs;
1209 	int curr_sect;
1210 	u32 fragm_no;
1211 
1212 again:
1213 	fragm_no = 1;
1214 	max_pkt = sender->max_pkt - INT_H_SIZE;
1215 		/* leave room for tunnel header in case of link changeover */
1216 	fragm_sz = max_pkt - INT_H_SIZE;
1217 		/* leave room for fragmentation header in each fragment */
1218 	rest = dsz;
1219 	fragm_crs = 0;
1220 	fragm_rest = 0;
1221 	sect_rest = 0;
1222 	sect_crs = NULL;
1223 	curr_sect = -1;
1224 
1225 	/* Prepare reusable fragment header: */
1226 
1227 	tipc_msg_init(&fragm_hdr, MSG_FRAGMENTER, FIRST_FRAGMENT,
1228 		 INT_H_SIZE, msg_destnode(hdr));
1229 	msg_set_size(&fragm_hdr, max_pkt);
1230 	msg_set_fragm_no(&fragm_hdr, 1);
1231 
1232 	/* Prepare header of first fragment: */
1233 
1234 	buf_chain = buf = tipc_buf_acquire(max_pkt);
1235 	if (!buf)
1236 		return -ENOMEM;
1237 	buf->next = NULL;
1238 	skb_copy_to_linear_data(buf, &fragm_hdr, INT_H_SIZE);
1239 	hsz = msg_hdr_sz(hdr);
1240 	skb_copy_to_linear_data_offset(buf, INT_H_SIZE, hdr, hsz);
1241 
1242 	/* Chop up message: */
1243 
1244 	fragm_crs = INT_H_SIZE + hsz;
1245 	fragm_rest = fragm_sz - hsz;
1246 
1247 	do {		/* For all sections */
1248 		u32 sz;
1249 
1250 		if (!sect_rest) {
1251 			sect_rest = msg_sect[++curr_sect].iov_len;
1252 			sect_crs = (const unchar *)msg_sect[curr_sect].iov_base;
1253 		}
1254 
1255 		if (sect_rest < fragm_rest)
1256 			sz = sect_rest;
1257 		else
1258 			sz = fragm_rest;
1259 
1260 		if (likely(!sender->user_port)) {
1261 			if (copy_from_user(buf->data + fragm_crs, sect_crs, sz)) {
1262 error:
1263 				for (; buf_chain; buf_chain = buf) {
1264 					buf = buf_chain->next;
1265 					buf_discard(buf_chain);
1266 				}
1267 				return -EFAULT;
1268 			}
1269 		} else
1270 			skb_copy_to_linear_data_offset(buf, fragm_crs,
1271 						       sect_crs, sz);
1272 		sect_crs += sz;
1273 		sect_rest -= sz;
1274 		fragm_crs += sz;
1275 		fragm_rest -= sz;
1276 		rest -= sz;
1277 
1278 		if (!fragm_rest && rest) {
1279 
1280 			/* Initiate new fragment: */
1281 			if (rest <= fragm_sz) {
1282 				fragm_sz = rest;
1283 				msg_set_type(&fragm_hdr, LAST_FRAGMENT);
1284 			} else {
1285 				msg_set_type(&fragm_hdr, FRAGMENT);
1286 			}
1287 			msg_set_size(&fragm_hdr, fragm_sz + INT_H_SIZE);
1288 			msg_set_fragm_no(&fragm_hdr, ++fragm_no);
1289 			prev = buf;
1290 			buf = tipc_buf_acquire(fragm_sz + INT_H_SIZE);
1291 			if (!buf)
1292 				goto error;
1293 
1294 			buf->next = NULL;
1295 			prev->next = buf;
1296 			skb_copy_to_linear_data(buf, &fragm_hdr, INT_H_SIZE);
1297 			fragm_crs = INT_H_SIZE;
1298 			fragm_rest = fragm_sz;
1299 		}
1300 	} while (rest > 0);
1301 
1302 	/*
1303 	 * Now we have a buffer chain. Select a link and check
1304 	 * that packet size is still OK
1305 	 */
1306 	node = tipc_node_find(destaddr);
1307 	if (likely(node)) {
1308 		tipc_node_lock(node);
1309 		l_ptr = node->active_links[sender->ref & 1];
1310 		if (!l_ptr) {
1311 			tipc_node_unlock(node);
1312 			goto reject;
1313 		}
1314 		if (l_ptr->max_pkt < max_pkt) {
1315 			sender->max_pkt = l_ptr->max_pkt;
1316 			tipc_node_unlock(node);
1317 			for (; buf_chain; buf_chain = buf) {
1318 				buf = buf_chain->next;
1319 				buf_discard(buf_chain);
1320 			}
1321 			goto again;
1322 		}
1323 	} else {
1324 reject:
1325 		for (; buf_chain; buf_chain = buf) {
1326 			buf = buf_chain->next;
1327 			buf_discard(buf_chain);
1328 		}
1329 		return tipc_port_reject_sections(sender, hdr, msg_sect, num_sect,
1330 						 total_len, TIPC_ERR_NO_NODE);
1331 	}
1332 
1333 	/* Append chain of fragments to send queue & send them */
1334 
1335 	l_ptr->long_msg_seq_no++;
1336 	link_add_chain_to_outqueue(l_ptr, buf_chain, l_ptr->long_msg_seq_no);
1337 	l_ptr->stats.sent_fragments += fragm_no;
1338 	l_ptr->stats.sent_fragmented++;
1339 	tipc_link_push_queue(l_ptr);
1340 	tipc_node_unlock(node);
1341 	return dsz;
1342 }
1343 
1344 /*
1345  * tipc_link_push_packet: Push one unsent packet to the media
1346  */
1347 u32 tipc_link_push_packet(struct tipc_link *l_ptr)
1348 {
1349 	struct sk_buff *buf = l_ptr->first_out;
1350 	u32 r_q_size = l_ptr->retransm_queue_size;
1351 	u32 r_q_head = l_ptr->retransm_queue_head;
1352 
1353 	/* Step to position where retransmission failed, if any,    */
1354 	/* consider that buffers may have been released in meantime */
1355 
1356 	if (r_q_size && buf) {
1357 		u32 last = lesser(mod(r_q_head + r_q_size),
1358 				  link_last_sent(l_ptr));
1359 		u32 first = buf_seqno(buf);
1360 
1361 		while (buf && less(first, r_q_head)) {
1362 			first = mod(first + 1);
1363 			buf = buf->next;
1364 		}
1365 		l_ptr->retransm_queue_head = r_q_head = first;
1366 		l_ptr->retransm_queue_size = r_q_size = mod(last - first);
1367 	}
1368 
1369 	/* Continue retransmission now, if there is anything: */
1370 
1371 	if (r_q_size && buf) {
1372 		msg_set_ack(buf_msg(buf), mod(l_ptr->next_in_no - 1));
1373 		msg_set_bcast_ack(buf_msg(buf), l_ptr->owner->bclink.last_in);
1374 		if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1375 			l_ptr->retransm_queue_head = mod(++r_q_head);
1376 			l_ptr->retransm_queue_size = --r_q_size;
1377 			l_ptr->stats.retransmitted++;
1378 			return 0;
1379 		} else {
1380 			l_ptr->stats.bearer_congs++;
1381 			return PUSH_FAILED;
1382 		}
1383 	}
1384 
1385 	/* Send deferred protocol message, if any: */
1386 
1387 	buf = l_ptr->proto_msg_queue;
1388 	if (buf) {
1389 		msg_set_ack(buf_msg(buf), mod(l_ptr->next_in_no - 1));
1390 		msg_set_bcast_ack(buf_msg(buf), l_ptr->owner->bclink.last_in);
1391 		if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1392 			l_ptr->unacked_window = 0;
1393 			buf_discard(buf);
1394 			l_ptr->proto_msg_queue = NULL;
1395 			return 0;
1396 		} else {
1397 			l_ptr->stats.bearer_congs++;
1398 			return PUSH_FAILED;
1399 		}
1400 	}
1401 
1402 	/* Send one deferred data message, if send window not full: */
1403 
1404 	buf = l_ptr->next_out;
1405 	if (buf) {
1406 		struct tipc_msg *msg = buf_msg(buf);
1407 		u32 next = msg_seqno(msg);
1408 		u32 first = buf_seqno(l_ptr->first_out);
1409 
1410 		if (mod(next - first) < l_ptr->queue_limit[0]) {
1411 			msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1412 			msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1413 			if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1414 				if (msg_user(msg) == MSG_BUNDLER)
1415 					msg_set_type(msg, CLOSED_MSG);
1416 				l_ptr->next_out = buf->next;
1417 				return 0;
1418 			} else {
1419 				l_ptr->stats.bearer_congs++;
1420 				return PUSH_FAILED;
1421 			}
1422 		}
1423 	}
1424 	return PUSH_FINISHED;
1425 }
1426 
1427 /*
1428  * push_queue(): push out the unsent messages of a link where
1429  *               congestion has abated. Node is locked
1430  */
1431 void tipc_link_push_queue(struct tipc_link *l_ptr)
1432 {
1433 	u32 res;
1434 
1435 	if (tipc_bearer_congested(l_ptr->b_ptr, l_ptr))
1436 		return;
1437 
1438 	do {
1439 		res = tipc_link_push_packet(l_ptr);
1440 	} while (!res);
1441 
1442 	if (res == PUSH_FAILED)
1443 		tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
1444 }
1445 
1446 static void link_reset_all(unsigned long addr)
1447 {
1448 	struct tipc_node *n_ptr;
1449 	char addr_string[16];
1450 	u32 i;
1451 
1452 	read_lock_bh(&tipc_net_lock);
1453 	n_ptr = tipc_node_find((u32)addr);
1454 	if (!n_ptr) {
1455 		read_unlock_bh(&tipc_net_lock);
1456 		return;	/* node no longer exists */
1457 	}
1458 
1459 	tipc_node_lock(n_ptr);
1460 
1461 	warn("Resetting all links to %s\n",
1462 	     tipc_addr_string_fill(addr_string, n_ptr->addr));
1463 
1464 	for (i = 0; i < MAX_BEARERS; i++) {
1465 		if (n_ptr->links[i]) {
1466 			link_print(n_ptr->links[i], "Resetting link\n");
1467 			tipc_link_reset(n_ptr->links[i]);
1468 		}
1469 	}
1470 
1471 	tipc_node_unlock(n_ptr);
1472 	read_unlock_bh(&tipc_net_lock);
1473 }
1474 
1475 static void link_retransmit_failure(struct tipc_link *l_ptr,
1476 					struct sk_buff *buf)
1477 {
1478 	struct tipc_msg *msg = buf_msg(buf);
1479 
1480 	warn("Retransmission failure on link <%s>\n", l_ptr->name);
1481 
1482 	if (l_ptr->addr) {
1483 
1484 		/* Handle failure on standard link */
1485 
1486 		link_print(l_ptr, "Resetting link\n");
1487 		tipc_link_reset(l_ptr);
1488 
1489 	} else {
1490 
1491 		/* Handle failure on broadcast link */
1492 
1493 		struct tipc_node *n_ptr;
1494 		char addr_string[16];
1495 
1496 		info("Msg seq number: %u,  ", msg_seqno(msg));
1497 		info("Outstanding acks: %lu\n",
1498 		     (unsigned long) TIPC_SKB_CB(buf)->handle);
1499 
1500 		n_ptr = tipc_bclink_retransmit_to();
1501 		tipc_node_lock(n_ptr);
1502 
1503 		tipc_addr_string_fill(addr_string, n_ptr->addr);
1504 		info("Broadcast link info for %s\n", addr_string);
1505 		info("Supportable: %d,  ", n_ptr->bclink.supportable);
1506 		info("Supported: %d,  ", n_ptr->bclink.supported);
1507 		info("Acked: %u\n", n_ptr->bclink.acked);
1508 		info("Last in: %u,  ", n_ptr->bclink.last_in);
1509 		info("Oos state: %u,  ", n_ptr->bclink.oos_state);
1510 		info("Last sent: %u\n", n_ptr->bclink.last_sent);
1511 
1512 		tipc_k_signal((Handler)link_reset_all, (unsigned long)n_ptr->addr);
1513 
1514 		tipc_node_unlock(n_ptr);
1515 
1516 		l_ptr->stale_count = 0;
1517 	}
1518 }
1519 
1520 void tipc_link_retransmit(struct tipc_link *l_ptr, struct sk_buff *buf,
1521 			  u32 retransmits)
1522 {
1523 	struct tipc_msg *msg;
1524 
1525 	if (!buf)
1526 		return;
1527 
1528 	msg = buf_msg(buf);
1529 
1530 	if (tipc_bearer_congested(l_ptr->b_ptr, l_ptr)) {
1531 		if (l_ptr->retransm_queue_size == 0) {
1532 			l_ptr->retransm_queue_head = msg_seqno(msg);
1533 			l_ptr->retransm_queue_size = retransmits;
1534 		} else {
1535 			err("Unexpected retransmit on link %s (qsize=%d)\n",
1536 			    l_ptr->name, l_ptr->retransm_queue_size);
1537 		}
1538 		return;
1539 	} else {
1540 		/* Detect repeated retransmit failures on uncongested bearer */
1541 
1542 		if (l_ptr->last_retransmitted == msg_seqno(msg)) {
1543 			if (++l_ptr->stale_count > 100) {
1544 				link_retransmit_failure(l_ptr, buf);
1545 				return;
1546 			}
1547 		} else {
1548 			l_ptr->last_retransmitted = msg_seqno(msg);
1549 			l_ptr->stale_count = 1;
1550 		}
1551 	}
1552 
1553 	while (retransmits && (buf != l_ptr->next_out) && buf) {
1554 		msg = buf_msg(buf);
1555 		msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1556 		msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1557 		if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1558 			buf = buf->next;
1559 			retransmits--;
1560 			l_ptr->stats.retransmitted++;
1561 		} else {
1562 			tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
1563 			l_ptr->stats.bearer_congs++;
1564 			l_ptr->retransm_queue_head = buf_seqno(buf);
1565 			l_ptr->retransm_queue_size = retransmits;
1566 			return;
1567 		}
1568 	}
1569 
1570 	l_ptr->retransm_queue_head = l_ptr->retransm_queue_size = 0;
1571 }
1572 
1573 /**
1574  * link_insert_deferred_queue - insert deferred messages back into receive chain
1575  */
1576 
1577 static struct sk_buff *link_insert_deferred_queue(struct tipc_link *l_ptr,
1578 						  struct sk_buff *buf)
1579 {
1580 	u32 seq_no;
1581 
1582 	if (l_ptr->oldest_deferred_in == NULL)
1583 		return buf;
1584 
1585 	seq_no = buf_seqno(l_ptr->oldest_deferred_in);
1586 	if (seq_no == mod(l_ptr->next_in_no)) {
1587 		l_ptr->newest_deferred_in->next = buf;
1588 		buf = l_ptr->oldest_deferred_in;
1589 		l_ptr->oldest_deferred_in = NULL;
1590 		l_ptr->deferred_inqueue_sz = 0;
1591 	}
1592 	return buf;
1593 }
1594 
1595 /**
1596  * link_recv_buf_validate - validate basic format of received message
1597  *
1598  * This routine ensures a TIPC message has an acceptable header, and at least
1599  * as much data as the header indicates it should.  The routine also ensures
1600  * that the entire message header is stored in the main fragment of the message
1601  * buffer, to simplify future access to message header fields.
1602  *
1603  * Note: Having extra info present in the message header or data areas is OK.
1604  * TIPC will ignore the excess, under the assumption that it is optional info
1605  * introduced by a later release of the protocol.
1606  */
1607 
1608 static int link_recv_buf_validate(struct sk_buff *buf)
1609 {
1610 	static u32 min_data_hdr_size[8] = {
1611 		SHORT_H_SIZE, MCAST_H_SIZE, NAMED_H_SIZE, BASIC_H_SIZE,
1612 		MAX_H_SIZE, MAX_H_SIZE, MAX_H_SIZE, MAX_H_SIZE
1613 		};
1614 
1615 	struct tipc_msg *msg;
1616 	u32 tipc_hdr[2];
1617 	u32 size;
1618 	u32 hdr_size;
1619 	u32 min_hdr_size;
1620 
1621 	if (unlikely(buf->len < MIN_H_SIZE))
1622 		return 0;
1623 
1624 	msg = skb_header_pointer(buf, 0, sizeof(tipc_hdr), tipc_hdr);
1625 	if (msg == NULL)
1626 		return 0;
1627 
1628 	if (unlikely(msg_version(msg) != TIPC_VERSION))
1629 		return 0;
1630 
1631 	size = msg_size(msg);
1632 	hdr_size = msg_hdr_sz(msg);
1633 	min_hdr_size = msg_isdata(msg) ?
1634 		min_data_hdr_size[msg_type(msg)] : INT_H_SIZE;
1635 
1636 	if (unlikely((hdr_size < min_hdr_size) ||
1637 		     (size < hdr_size) ||
1638 		     (buf->len < size) ||
1639 		     (size - hdr_size > TIPC_MAX_USER_MSG_SIZE)))
1640 		return 0;
1641 
1642 	return pskb_may_pull(buf, hdr_size);
1643 }
1644 
1645 /**
1646  * tipc_recv_msg - process TIPC messages arriving from off-node
1647  * @head: pointer to message buffer chain
1648  * @tb_ptr: pointer to bearer message arrived on
1649  *
1650  * Invoked with no locks held.  Bearer pointer must point to a valid bearer
1651  * structure (i.e. cannot be NULL), but bearer can be inactive.
1652  */
1653 
1654 void tipc_recv_msg(struct sk_buff *head, struct tipc_bearer *b_ptr)
1655 {
1656 	read_lock_bh(&tipc_net_lock);
1657 	while (head) {
1658 		struct tipc_node *n_ptr;
1659 		struct tipc_link *l_ptr;
1660 		struct sk_buff *crs;
1661 		struct sk_buff *buf = head;
1662 		struct tipc_msg *msg;
1663 		u32 seq_no;
1664 		u32 ackd;
1665 		u32 released = 0;
1666 		int type;
1667 
1668 		head = head->next;
1669 
1670 		/* Ensure bearer is still enabled */
1671 
1672 		if (unlikely(!b_ptr->active))
1673 			goto cont;
1674 
1675 		/* Ensure message is well-formed */
1676 
1677 		if (unlikely(!link_recv_buf_validate(buf)))
1678 			goto cont;
1679 
1680 		/* Ensure message data is a single contiguous unit */
1681 
1682 		if (unlikely(buf_linearize(buf)))
1683 			goto cont;
1684 
1685 		/* Handle arrival of a non-unicast link message */
1686 
1687 		msg = buf_msg(buf);
1688 
1689 		if (unlikely(msg_non_seq(msg))) {
1690 			if (msg_user(msg) ==  LINK_CONFIG)
1691 				tipc_disc_recv_msg(buf, b_ptr);
1692 			else
1693 				tipc_bclink_recv_pkt(buf);
1694 			continue;
1695 		}
1696 
1697 		/* Discard unicast link messages destined for another node */
1698 
1699 		if (unlikely(!msg_short(msg) &&
1700 			     (msg_destnode(msg) != tipc_own_addr)))
1701 			goto cont;
1702 
1703 		/* Locate neighboring node that sent message */
1704 
1705 		n_ptr = tipc_node_find(msg_prevnode(msg));
1706 		if (unlikely(!n_ptr))
1707 			goto cont;
1708 		tipc_node_lock(n_ptr);
1709 
1710 		/* Locate unicast link endpoint that should handle message */
1711 
1712 		l_ptr = n_ptr->links[b_ptr->identity];
1713 		if (unlikely(!l_ptr)) {
1714 			tipc_node_unlock(n_ptr);
1715 			goto cont;
1716 		}
1717 
1718 		/* Verify that communication with node is currently allowed */
1719 
1720 		if ((n_ptr->block_setup & WAIT_PEER_DOWN) &&
1721 			msg_user(msg) == LINK_PROTOCOL &&
1722 			(msg_type(msg) == RESET_MSG ||
1723 					msg_type(msg) == ACTIVATE_MSG) &&
1724 			!msg_redundant_link(msg))
1725 			n_ptr->block_setup &= ~WAIT_PEER_DOWN;
1726 
1727 		if (n_ptr->block_setup) {
1728 			tipc_node_unlock(n_ptr);
1729 			goto cont;
1730 		}
1731 
1732 		/* Validate message sequence number info */
1733 
1734 		seq_no = msg_seqno(msg);
1735 		ackd = msg_ack(msg);
1736 
1737 		/* Release acked messages */
1738 
1739 		if (n_ptr->bclink.supported)
1740 			tipc_bclink_acknowledge(n_ptr, msg_bcast_ack(msg));
1741 
1742 		crs = l_ptr->first_out;
1743 		while ((crs != l_ptr->next_out) &&
1744 		       less_eq(buf_seqno(crs), ackd)) {
1745 			struct sk_buff *next = crs->next;
1746 
1747 			buf_discard(crs);
1748 			crs = next;
1749 			released++;
1750 		}
1751 		if (released) {
1752 			l_ptr->first_out = crs;
1753 			l_ptr->out_queue_size -= released;
1754 		}
1755 
1756 		/* Try sending any messages link endpoint has pending */
1757 
1758 		if (unlikely(l_ptr->next_out))
1759 			tipc_link_push_queue(l_ptr);
1760 		if (unlikely(!list_empty(&l_ptr->waiting_ports)))
1761 			tipc_link_wakeup_ports(l_ptr, 0);
1762 		if (unlikely(++l_ptr->unacked_window >= TIPC_MIN_LINK_WIN)) {
1763 			l_ptr->stats.sent_acks++;
1764 			tipc_link_send_proto_msg(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
1765 		}
1766 
1767 		/* Now (finally!) process the incoming message */
1768 
1769 protocol_check:
1770 		if (likely(link_working_working(l_ptr))) {
1771 			if (likely(seq_no == mod(l_ptr->next_in_no))) {
1772 				l_ptr->next_in_no++;
1773 				if (unlikely(l_ptr->oldest_deferred_in))
1774 					head = link_insert_deferred_queue(l_ptr,
1775 									  head);
1776 				if (likely(msg_is_dest(msg, tipc_own_addr))) {
1777 					int ret;
1778 deliver:
1779 					if (likely(msg_isdata(msg))) {
1780 						tipc_node_unlock(n_ptr);
1781 						tipc_port_recv_msg(buf);
1782 						continue;
1783 					}
1784 					switch (msg_user(msg)) {
1785 					case MSG_BUNDLER:
1786 						l_ptr->stats.recv_bundles++;
1787 						l_ptr->stats.recv_bundled +=
1788 							msg_msgcnt(msg);
1789 						tipc_node_unlock(n_ptr);
1790 						tipc_link_recv_bundle(buf);
1791 						continue;
1792 					case NAME_DISTRIBUTOR:
1793 						tipc_node_unlock(n_ptr);
1794 						tipc_named_recv(buf);
1795 						continue;
1796 					case CONN_MANAGER:
1797 						tipc_node_unlock(n_ptr);
1798 						tipc_port_recv_proto_msg(buf);
1799 						continue;
1800 					case MSG_FRAGMENTER:
1801 						l_ptr->stats.recv_fragments++;
1802 						ret = tipc_link_recv_fragment(
1803 							&l_ptr->defragm_buf,
1804 							&buf, &msg);
1805 						if (ret == 1) {
1806 							l_ptr->stats.recv_fragmented++;
1807 							goto deliver;
1808 						}
1809 						if (ret == -1)
1810 							l_ptr->next_in_no--;
1811 						break;
1812 					case CHANGEOVER_PROTOCOL:
1813 						type = msg_type(msg);
1814 						if (link_recv_changeover_msg(&l_ptr, &buf)) {
1815 							msg = buf_msg(buf);
1816 							seq_no = msg_seqno(msg);
1817 							if (type == ORIGINAL_MSG)
1818 								goto deliver;
1819 							goto protocol_check;
1820 						}
1821 						break;
1822 					default:
1823 						buf_discard(buf);
1824 						buf = NULL;
1825 						break;
1826 					}
1827 				}
1828 				tipc_node_unlock(n_ptr);
1829 				tipc_net_route_msg(buf);
1830 				continue;
1831 			}
1832 			link_handle_out_of_seq_msg(l_ptr, buf);
1833 			head = link_insert_deferred_queue(l_ptr, head);
1834 			tipc_node_unlock(n_ptr);
1835 			continue;
1836 		}
1837 
1838 		if (msg_user(msg) == LINK_PROTOCOL) {
1839 			link_recv_proto_msg(l_ptr, buf);
1840 			head = link_insert_deferred_queue(l_ptr, head);
1841 			tipc_node_unlock(n_ptr);
1842 			continue;
1843 		}
1844 		link_state_event(l_ptr, TRAFFIC_MSG_EVT);
1845 
1846 		if (link_working_working(l_ptr)) {
1847 			/* Re-insert in front of queue */
1848 			buf->next = head;
1849 			head = buf;
1850 			tipc_node_unlock(n_ptr);
1851 			continue;
1852 		}
1853 		tipc_node_unlock(n_ptr);
1854 cont:
1855 		buf_discard(buf);
1856 	}
1857 	read_unlock_bh(&tipc_net_lock);
1858 }
1859 
1860 /*
1861  * tipc_link_defer_pkt - Add out-of-sequence message to deferred reception queue
1862  *
1863  * Returns increase in queue length (i.e. 0 or 1)
1864  */
1865 
1866 u32 tipc_link_defer_pkt(struct sk_buff **head, struct sk_buff **tail,
1867 			struct sk_buff *buf)
1868 {
1869 	struct sk_buff *queue_buf;
1870 	struct sk_buff **prev;
1871 	u32 seq_no = buf_seqno(buf);
1872 
1873 	buf->next = NULL;
1874 
1875 	/* Empty queue ? */
1876 	if (*head == NULL) {
1877 		*head = *tail = buf;
1878 		return 1;
1879 	}
1880 
1881 	/* Last ? */
1882 	if (less(buf_seqno(*tail), seq_no)) {
1883 		(*tail)->next = buf;
1884 		*tail = buf;
1885 		return 1;
1886 	}
1887 
1888 	/* Locate insertion point in queue, then insert; discard if duplicate */
1889 	prev = head;
1890 	queue_buf = *head;
1891 	for (;;) {
1892 		u32 curr_seqno = buf_seqno(queue_buf);
1893 
1894 		if (seq_no == curr_seqno) {
1895 			buf_discard(buf);
1896 			return 0;
1897 		}
1898 
1899 		if (less(seq_no, curr_seqno))
1900 			break;
1901 
1902 		prev = &queue_buf->next;
1903 		queue_buf = queue_buf->next;
1904 	}
1905 
1906 	buf->next = queue_buf;
1907 	*prev = buf;
1908 	return 1;
1909 }
1910 
1911 /*
1912  * link_handle_out_of_seq_msg - handle arrival of out-of-sequence packet
1913  */
1914 
1915 static void link_handle_out_of_seq_msg(struct tipc_link *l_ptr,
1916 				       struct sk_buff *buf)
1917 {
1918 	u32 seq_no = buf_seqno(buf);
1919 
1920 	if (likely(msg_user(buf_msg(buf)) == LINK_PROTOCOL)) {
1921 		link_recv_proto_msg(l_ptr, buf);
1922 		return;
1923 	}
1924 
1925 	/* Record OOS packet arrival (force mismatch on next timeout) */
1926 
1927 	l_ptr->checkpoint--;
1928 
1929 	/*
1930 	 * Discard packet if a duplicate; otherwise add it to deferred queue
1931 	 * and notify peer of gap as per protocol specification
1932 	 */
1933 
1934 	if (less(seq_no, mod(l_ptr->next_in_no))) {
1935 		l_ptr->stats.duplicates++;
1936 		buf_discard(buf);
1937 		return;
1938 	}
1939 
1940 	if (tipc_link_defer_pkt(&l_ptr->oldest_deferred_in,
1941 				&l_ptr->newest_deferred_in, buf)) {
1942 		l_ptr->deferred_inqueue_sz++;
1943 		l_ptr->stats.deferred_recv++;
1944 		if ((l_ptr->deferred_inqueue_sz % 16) == 1)
1945 			tipc_link_send_proto_msg(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
1946 	} else
1947 		l_ptr->stats.duplicates++;
1948 }
1949 
1950 /*
1951  * Send protocol message to the other endpoint.
1952  */
1953 void tipc_link_send_proto_msg(struct tipc_link *l_ptr, u32 msg_typ,
1954 				int probe_msg, u32 gap, u32 tolerance,
1955 				u32 priority, u32 ack_mtu)
1956 {
1957 	struct sk_buff *buf = NULL;
1958 	struct tipc_msg *msg = l_ptr->pmsg;
1959 	u32 msg_size = sizeof(l_ptr->proto_msg);
1960 	int r_flag;
1961 
1962 	/* Discard any previous message that was deferred due to congestion */
1963 
1964 	if (l_ptr->proto_msg_queue) {
1965 		buf_discard(l_ptr->proto_msg_queue);
1966 		l_ptr->proto_msg_queue = NULL;
1967 	}
1968 
1969 	if (link_blocked(l_ptr))
1970 		return;
1971 
1972 	/* Abort non-RESET send if communication with node is prohibited */
1973 
1974 	if ((l_ptr->owner->block_setup) && (msg_typ != RESET_MSG))
1975 		return;
1976 
1977 	/* Create protocol message with "out-of-sequence" sequence number */
1978 
1979 	msg_set_type(msg, msg_typ);
1980 	msg_set_net_plane(msg, l_ptr->b_ptr->net_plane);
1981 	msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1982 	msg_set_last_bcast(msg, tipc_bclink_get_last_sent());
1983 
1984 	if (msg_typ == STATE_MSG) {
1985 		u32 next_sent = mod(l_ptr->next_out_no);
1986 
1987 		if (!tipc_link_is_up(l_ptr))
1988 			return;
1989 		if (l_ptr->next_out)
1990 			next_sent = buf_seqno(l_ptr->next_out);
1991 		msg_set_next_sent(msg, next_sent);
1992 		if (l_ptr->oldest_deferred_in) {
1993 			u32 rec = buf_seqno(l_ptr->oldest_deferred_in);
1994 			gap = mod(rec - mod(l_ptr->next_in_no));
1995 		}
1996 		msg_set_seq_gap(msg, gap);
1997 		if (gap)
1998 			l_ptr->stats.sent_nacks++;
1999 		msg_set_link_tolerance(msg, tolerance);
2000 		msg_set_linkprio(msg, priority);
2001 		msg_set_max_pkt(msg, ack_mtu);
2002 		msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
2003 		msg_set_probe(msg, probe_msg != 0);
2004 		if (probe_msg) {
2005 			u32 mtu = l_ptr->max_pkt;
2006 
2007 			if ((mtu < l_ptr->max_pkt_target) &&
2008 			    link_working_working(l_ptr) &&
2009 			    l_ptr->fsm_msg_cnt) {
2010 				msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
2011 				if (l_ptr->max_pkt_probes == 10) {
2012 					l_ptr->max_pkt_target = (msg_size - 4);
2013 					l_ptr->max_pkt_probes = 0;
2014 					msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
2015 				}
2016 				l_ptr->max_pkt_probes++;
2017 			}
2018 
2019 			l_ptr->stats.sent_probes++;
2020 		}
2021 		l_ptr->stats.sent_states++;
2022 	} else {		/* RESET_MSG or ACTIVATE_MSG */
2023 		msg_set_ack(msg, mod(l_ptr->reset_checkpoint - 1));
2024 		msg_set_seq_gap(msg, 0);
2025 		msg_set_next_sent(msg, 1);
2026 		msg_set_probe(msg, 0);
2027 		msg_set_link_tolerance(msg, l_ptr->tolerance);
2028 		msg_set_linkprio(msg, l_ptr->priority);
2029 		msg_set_max_pkt(msg, l_ptr->max_pkt_target);
2030 	}
2031 
2032 	r_flag = (l_ptr->owner->working_links > tipc_link_is_up(l_ptr));
2033 	msg_set_redundant_link(msg, r_flag);
2034 	msg_set_linkprio(msg, l_ptr->priority);
2035 	msg_set_size(msg, msg_size);
2036 
2037 	msg_set_seqno(msg, mod(l_ptr->next_out_no + (0xffff/2)));
2038 
2039 	buf = tipc_buf_acquire(msg_size);
2040 	if (!buf)
2041 		return;
2042 
2043 	skb_copy_to_linear_data(buf, msg, sizeof(l_ptr->proto_msg));
2044 
2045 	/* Defer message if bearer is already congested */
2046 
2047 	if (tipc_bearer_congested(l_ptr->b_ptr, l_ptr)) {
2048 		l_ptr->proto_msg_queue = buf;
2049 		return;
2050 	}
2051 
2052 	/* Defer message if attempting to send results in bearer congestion */
2053 
2054 	if (!tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
2055 		tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
2056 		l_ptr->proto_msg_queue = buf;
2057 		l_ptr->stats.bearer_congs++;
2058 		return;
2059 	}
2060 
2061 	/* Discard message if it was sent successfully */
2062 
2063 	l_ptr->unacked_window = 0;
2064 	buf_discard(buf);
2065 }
2066 
2067 /*
2068  * Receive protocol message :
2069  * Note that network plane id propagates through the network, and may
2070  * change at any time. The node with lowest address rules
2071  */
2072 
2073 static void link_recv_proto_msg(struct tipc_link *l_ptr, struct sk_buff *buf)
2074 {
2075 	u32 rec_gap = 0;
2076 	u32 max_pkt_info;
2077 	u32 max_pkt_ack;
2078 	u32 msg_tol;
2079 	struct tipc_msg *msg = buf_msg(buf);
2080 
2081 	if (link_blocked(l_ptr))
2082 		goto exit;
2083 
2084 	/* record unnumbered packet arrival (force mismatch on next timeout) */
2085 
2086 	l_ptr->checkpoint--;
2087 
2088 	if (l_ptr->b_ptr->net_plane != msg_net_plane(msg))
2089 		if (tipc_own_addr > msg_prevnode(msg))
2090 			l_ptr->b_ptr->net_plane = msg_net_plane(msg);
2091 
2092 	l_ptr->owner->permit_changeover = msg_redundant_link(msg);
2093 
2094 	switch (msg_type(msg)) {
2095 
2096 	case RESET_MSG:
2097 		if (!link_working_unknown(l_ptr) &&
2098 		    (l_ptr->peer_session != INVALID_SESSION)) {
2099 			if (less_eq(msg_session(msg), l_ptr->peer_session))
2100 				break; /* duplicate or old reset: ignore */
2101 		}
2102 
2103 		if (!msg_redundant_link(msg) && (link_working_working(l_ptr) ||
2104 				link_working_unknown(l_ptr))) {
2105 			/*
2106 			 * peer has lost contact -- don't allow peer's links
2107 			 * to reactivate before we recognize loss & clean up
2108 			 */
2109 			l_ptr->owner->block_setup = WAIT_NODE_DOWN;
2110 		}
2111 
2112 		link_state_event(l_ptr, RESET_MSG);
2113 
2114 		/* fall thru' */
2115 	case ACTIVATE_MSG:
2116 		/* Update link settings according other endpoint's values */
2117 
2118 		strcpy((strrchr(l_ptr->name, ':') + 1), (char *)msg_data(msg));
2119 
2120 		msg_tol = msg_link_tolerance(msg);
2121 		if (msg_tol > l_ptr->tolerance)
2122 			link_set_supervision_props(l_ptr, msg_tol);
2123 
2124 		if (msg_linkprio(msg) > l_ptr->priority)
2125 			l_ptr->priority = msg_linkprio(msg);
2126 
2127 		max_pkt_info = msg_max_pkt(msg);
2128 		if (max_pkt_info) {
2129 			if (max_pkt_info < l_ptr->max_pkt_target)
2130 				l_ptr->max_pkt_target = max_pkt_info;
2131 			if (l_ptr->max_pkt > l_ptr->max_pkt_target)
2132 				l_ptr->max_pkt = l_ptr->max_pkt_target;
2133 		} else {
2134 			l_ptr->max_pkt = l_ptr->max_pkt_target;
2135 		}
2136 		l_ptr->owner->bclink.supportable = (max_pkt_info != 0);
2137 
2138 		/* Synchronize broadcast link info, if not done previously */
2139 
2140 		if (!tipc_node_is_up(l_ptr->owner)) {
2141 			l_ptr->owner->bclink.last_sent =
2142 				l_ptr->owner->bclink.last_in =
2143 				msg_last_bcast(msg);
2144 			l_ptr->owner->bclink.oos_state = 0;
2145 		}
2146 
2147 		l_ptr->peer_session = msg_session(msg);
2148 		l_ptr->peer_bearer_id = msg_bearer_id(msg);
2149 
2150 		if (msg_type(msg) == ACTIVATE_MSG)
2151 			link_state_event(l_ptr, ACTIVATE_MSG);
2152 		break;
2153 	case STATE_MSG:
2154 
2155 		msg_tol = msg_link_tolerance(msg);
2156 		if (msg_tol)
2157 			link_set_supervision_props(l_ptr, msg_tol);
2158 
2159 		if (msg_linkprio(msg) &&
2160 		    (msg_linkprio(msg) != l_ptr->priority)) {
2161 			warn("Resetting link <%s>, priority change %u->%u\n",
2162 			     l_ptr->name, l_ptr->priority, msg_linkprio(msg));
2163 			l_ptr->priority = msg_linkprio(msg);
2164 			tipc_link_reset(l_ptr); /* Enforce change to take effect */
2165 			break;
2166 		}
2167 		link_state_event(l_ptr, TRAFFIC_MSG_EVT);
2168 		l_ptr->stats.recv_states++;
2169 		if (link_reset_unknown(l_ptr))
2170 			break;
2171 
2172 		if (less_eq(mod(l_ptr->next_in_no), msg_next_sent(msg))) {
2173 			rec_gap = mod(msg_next_sent(msg) -
2174 				      mod(l_ptr->next_in_no));
2175 		}
2176 
2177 		max_pkt_ack = msg_max_pkt(msg);
2178 		if (max_pkt_ack > l_ptr->max_pkt) {
2179 			l_ptr->max_pkt = max_pkt_ack;
2180 			l_ptr->max_pkt_probes = 0;
2181 		}
2182 
2183 		max_pkt_ack = 0;
2184 		if (msg_probe(msg)) {
2185 			l_ptr->stats.recv_probes++;
2186 			if (msg_size(msg) > sizeof(l_ptr->proto_msg))
2187 				max_pkt_ack = msg_size(msg);
2188 		}
2189 
2190 		/* Protocol message before retransmits, reduce loss risk */
2191 
2192 		if (l_ptr->owner->bclink.supported)
2193 			tipc_bclink_update_link_state(l_ptr->owner,
2194 						      msg_last_bcast(msg));
2195 
2196 		if (rec_gap || (msg_probe(msg))) {
2197 			tipc_link_send_proto_msg(l_ptr, STATE_MSG,
2198 						 0, rec_gap, 0, 0, max_pkt_ack);
2199 		}
2200 		if (msg_seq_gap(msg)) {
2201 			l_ptr->stats.recv_nacks++;
2202 			tipc_link_retransmit(l_ptr, l_ptr->first_out,
2203 					     msg_seq_gap(msg));
2204 		}
2205 		break;
2206 	}
2207 exit:
2208 	buf_discard(buf);
2209 }
2210 
2211 
2212 /*
2213  * tipc_link_tunnel(): Send one message via a link belonging to
2214  * another bearer. Owner node is locked.
2215  */
2216 static void tipc_link_tunnel(struct tipc_link *l_ptr,
2217 			     struct tipc_msg *tunnel_hdr,
2218 			     struct tipc_msg  *msg,
2219 			     u32 selector)
2220 {
2221 	struct tipc_link *tunnel;
2222 	struct sk_buff *buf;
2223 	u32 length = msg_size(msg);
2224 
2225 	tunnel = l_ptr->owner->active_links[selector & 1];
2226 	if (!tipc_link_is_up(tunnel)) {
2227 		warn("Link changeover error, "
2228 		     "tunnel link no longer available\n");
2229 		return;
2230 	}
2231 	msg_set_size(tunnel_hdr, length + INT_H_SIZE);
2232 	buf = tipc_buf_acquire(length + INT_H_SIZE);
2233 	if (!buf) {
2234 		warn("Link changeover error, "
2235 		     "unable to send tunnel msg\n");
2236 		return;
2237 	}
2238 	skb_copy_to_linear_data(buf, tunnel_hdr, INT_H_SIZE);
2239 	skb_copy_to_linear_data_offset(buf, INT_H_SIZE, msg, length);
2240 	tipc_link_send_buf(tunnel, buf);
2241 }
2242 
2243 
2244 
2245 /*
2246  * changeover(): Send whole message queue via the remaining link
2247  *               Owner node is locked.
2248  */
2249 
2250 void tipc_link_changeover(struct tipc_link *l_ptr)
2251 {
2252 	u32 msgcount = l_ptr->out_queue_size;
2253 	struct sk_buff *crs = l_ptr->first_out;
2254 	struct tipc_link *tunnel = l_ptr->owner->active_links[0];
2255 	struct tipc_msg tunnel_hdr;
2256 	int split_bundles;
2257 
2258 	if (!tunnel)
2259 		return;
2260 
2261 	if (!l_ptr->owner->permit_changeover) {
2262 		warn("Link changeover error, "
2263 		     "peer did not permit changeover\n");
2264 		return;
2265 	}
2266 
2267 	tipc_msg_init(&tunnel_hdr, CHANGEOVER_PROTOCOL,
2268 		 ORIGINAL_MSG, INT_H_SIZE, l_ptr->addr);
2269 	msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
2270 	msg_set_msgcnt(&tunnel_hdr, msgcount);
2271 
2272 	if (!l_ptr->first_out) {
2273 		struct sk_buff *buf;
2274 
2275 		buf = tipc_buf_acquire(INT_H_SIZE);
2276 		if (buf) {
2277 			skb_copy_to_linear_data(buf, &tunnel_hdr, INT_H_SIZE);
2278 			msg_set_size(&tunnel_hdr, INT_H_SIZE);
2279 			tipc_link_send_buf(tunnel, buf);
2280 		} else {
2281 			warn("Link changeover error, "
2282 			     "unable to send changeover msg\n");
2283 		}
2284 		return;
2285 	}
2286 
2287 	split_bundles = (l_ptr->owner->active_links[0] !=
2288 			 l_ptr->owner->active_links[1]);
2289 
2290 	while (crs) {
2291 		struct tipc_msg *msg = buf_msg(crs);
2292 
2293 		if ((msg_user(msg) == MSG_BUNDLER) && split_bundles) {
2294 			struct tipc_msg *m = msg_get_wrapped(msg);
2295 			unchar *pos = (unchar *)m;
2296 
2297 			msgcount = msg_msgcnt(msg);
2298 			while (msgcount--) {
2299 				msg_set_seqno(m, msg_seqno(msg));
2300 				tipc_link_tunnel(l_ptr, &tunnel_hdr, m,
2301 						 msg_link_selector(m));
2302 				pos += align(msg_size(m));
2303 				m = (struct tipc_msg *)pos;
2304 			}
2305 		} else {
2306 			tipc_link_tunnel(l_ptr, &tunnel_hdr, msg,
2307 					 msg_link_selector(msg));
2308 		}
2309 		crs = crs->next;
2310 	}
2311 }
2312 
2313 void tipc_link_send_duplicate(struct tipc_link *l_ptr, struct tipc_link *tunnel)
2314 {
2315 	struct sk_buff *iter;
2316 	struct tipc_msg tunnel_hdr;
2317 
2318 	tipc_msg_init(&tunnel_hdr, CHANGEOVER_PROTOCOL,
2319 		 DUPLICATE_MSG, INT_H_SIZE, l_ptr->addr);
2320 	msg_set_msgcnt(&tunnel_hdr, l_ptr->out_queue_size);
2321 	msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
2322 	iter = l_ptr->first_out;
2323 	while (iter) {
2324 		struct sk_buff *outbuf;
2325 		struct tipc_msg *msg = buf_msg(iter);
2326 		u32 length = msg_size(msg);
2327 
2328 		if (msg_user(msg) == MSG_BUNDLER)
2329 			msg_set_type(msg, CLOSED_MSG);
2330 		msg_set_ack(msg, mod(l_ptr->next_in_no - 1));	/* Update */
2331 		msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
2332 		msg_set_size(&tunnel_hdr, length + INT_H_SIZE);
2333 		outbuf = tipc_buf_acquire(length + INT_H_SIZE);
2334 		if (outbuf == NULL) {
2335 			warn("Link changeover error, "
2336 			     "unable to send duplicate msg\n");
2337 			return;
2338 		}
2339 		skb_copy_to_linear_data(outbuf, &tunnel_hdr, INT_H_SIZE);
2340 		skb_copy_to_linear_data_offset(outbuf, INT_H_SIZE, iter->data,
2341 					       length);
2342 		tipc_link_send_buf(tunnel, outbuf);
2343 		if (!tipc_link_is_up(l_ptr))
2344 			return;
2345 		iter = iter->next;
2346 	}
2347 }
2348 
2349 
2350 
2351 /**
2352  * buf_extract - extracts embedded TIPC message from another message
2353  * @skb: encapsulating message buffer
2354  * @from_pos: offset to extract from
2355  *
2356  * Returns a new message buffer containing an embedded message.  The
2357  * encapsulating message itself is left unchanged.
2358  */
2359 
2360 static struct sk_buff *buf_extract(struct sk_buff *skb, u32 from_pos)
2361 {
2362 	struct tipc_msg *msg = (struct tipc_msg *)(skb->data + from_pos);
2363 	u32 size = msg_size(msg);
2364 	struct sk_buff *eb;
2365 
2366 	eb = tipc_buf_acquire(size);
2367 	if (eb)
2368 		skb_copy_to_linear_data(eb, msg, size);
2369 	return eb;
2370 }
2371 
2372 /*
2373  *  link_recv_changeover_msg(): Receive tunneled packet sent
2374  *  via other link. Node is locked. Return extracted buffer.
2375  */
2376 
2377 static int link_recv_changeover_msg(struct tipc_link **l_ptr,
2378 				    struct sk_buff **buf)
2379 {
2380 	struct sk_buff *tunnel_buf = *buf;
2381 	struct tipc_link *dest_link;
2382 	struct tipc_msg *msg;
2383 	struct tipc_msg *tunnel_msg = buf_msg(tunnel_buf);
2384 	u32 msg_typ = msg_type(tunnel_msg);
2385 	u32 msg_count = msg_msgcnt(tunnel_msg);
2386 
2387 	dest_link = (*l_ptr)->owner->links[msg_bearer_id(tunnel_msg)];
2388 	if (!dest_link)
2389 		goto exit;
2390 	if (dest_link == *l_ptr) {
2391 		err("Unexpected changeover message on link <%s>\n",
2392 		    (*l_ptr)->name);
2393 		goto exit;
2394 	}
2395 	*l_ptr = dest_link;
2396 	msg = msg_get_wrapped(tunnel_msg);
2397 
2398 	if (msg_typ == DUPLICATE_MSG) {
2399 		if (less(msg_seqno(msg), mod(dest_link->next_in_no)))
2400 			goto exit;
2401 		*buf = buf_extract(tunnel_buf, INT_H_SIZE);
2402 		if (*buf == NULL) {
2403 			warn("Link changeover error, duplicate msg dropped\n");
2404 			goto exit;
2405 		}
2406 		buf_discard(tunnel_buf);
2407 		return 1;
2408 	}
2409 
2410 	/* First original message ?: */
2411 
2412 	if (tipc_link_is_up(dest_link)) {
2413 		info("Resetting link <%s>, changeover initiated by peer\n",
2414 		     dest_link->name);
2415 		tipc_link_reset(dest_link);
2416 		dest_link->exp_msg_count = msg_count;
2417 		if (!msg_count)
2418 			goto exit;
2419 	} else if (dest_link->exp_msg_count == START_CHANGEOVER) {
2420 		dest_link->exp_msg_count = msg_count;
2421 		if (!msg_count)
2422 			goto exit;
2423 	}
2424 
2425 	/* Receive original message */
2426 
2427 	if (dest_link->exp_msg_count == 0) {
2428 		warn("Link switchover error, "
2429 		     "got too many tunnelled messages\n");
2430 		goto exit;
2431 	}
2432 	dest_link->exp_msg_count--;
2433 	if (less(msg_seqno(msg), dest_link->reset_checkpoint)) {
2434 		goto exit;
2435 	} else {
2436 		*buf = buf_extract(tunnel_buf, INT_H_SIZE);
2437 		if (*buf != NULL) {
2438 			buf_discard(tunnel_buf);
2439 			return 1;
2440 		} else {
2441 			warn("Link changeover error, original msg dropped\n");
2442 		}
2443 	}
2444 exit:
2445 	*buf = NULL;
2446 	buf_discard(tunnel_buf);
2447 	return 0;
2448 }
2449 
2450 /*
2451  *  Bundler functionality:
2452  */
2453 void tipc_link_recv_bundle(struct sk_buff *buf)
2454 {
2455 	u32 msgcount = msg_msgcnt(buf_msg(buf));
2456 	u32 pos = INT_H_SIZE;
2457 	struct sk_buff *obuf;
2458 
2459 	while (msgcount--) {
2460 		obuf = buf_extract(buf, pos);
2461 		if (obuf == NULL) {
2462 			warn("Link unable to unbundle message(s)\n");
2463 			break;
2464 		}
2465 		pos += align(msg_size(buf_msg(obuf)));
2466 		tipc_net_route_msg(obuf);
2467 	}
2468 	buf_discard(buf);
2469 }
2470 
2471 /*
2472  *  Fragmentation/defragmentation:
2473  */
2474 
2475 
2476 /*
2477  * link_send_long_buf: Entry for buffers needing fragmentation.
2478  * The buffer is complete, inclusive total message length.
2479  * Returns user data length.
2480  */
2481 static int link_send_long_buf(struct tipc_link *l_ptr, struct sk_buff *buf)
2482 {
2483 	struct sk_buff *buf_chain = NULL;
2484 	struct sk_buff *buf_chain_tail = (struct sk_buff *)&buf_chain;
2485 	struct tipc_msg *inmsg = buf_msg(buf);
2486 	struct tipc_msg fragm_hdr;
2487 	u32 insize = msg_size(inmsg);
2488 	u32 dsz = msg_data_sz(inmsg);
2489 	unchar *crs = buf->data;
2490 	u32 rest = insize;
2491 	u32 pack_sz = l_ptr->max_pkt;
2492 	u32 fragm_sz = pack_sz - INT_H_SIZE;
2493 	u32 fragm_no = 0;
2494 	u32 destaddr;
2495 
2496 	if (msg_short(inmsg))
2497 		destaddr = l_ptr->addr;
2498 	else
2499 		destaddr = msg_destnode(inmsg);
2500 
2501 	/* Prepare reusable fragment header: */
2502 
2503 	tipc_msg_init(&fragm_hdr, MSG_FRAGMENTER, FIRST_FRAGMENT,
2504 		 INT_H_SIZE, destaddr);
2505 
2506 	/* Chop up message: */
2507 
2508 	while (rest > 0) {
2509 		struct sk_buff *fragm;
2510 
2511 		if (rest <= fragm_sz) {
2512 			fragm_sz = rest;
2513 			msg_set_type(&fragm_hdr, LAST_FRAGMENT);
2514 		}
2515 		fragm = tipc_buf_acquire(fragm_sz + INT_H_SIZE);
2516 		if (fragm == NULL) {
2517 			buf_discard(buf);
2518 			while (buf_chain) {
2519 				buf = buf_chain;
2520 				buf_chain = buf_chain->next;
2521 				buf_discard(buf);
2522 			}
2523 			return -ENOMEM;
2524 		}
2525 		msg_set_size(&fragm_hdr, fragm_sz + INT_H_SIZE);
2526 		fragm_no++;
2527 		msg_set_fragm_no(&fragm_hdr, fragm_no);
2528 		skb_copy_to_linear_data(fragm, &fragm_hdr, INT_H_SIZE);
2529 		skb_copy_to_linear_data_offset(fragm, INT_H_SIZE, crs,
2530 					       fragm_sz);
2531 		buf_chain_tail->next = fragm;
2532 		buf_chain_tail = fragm;
2533 
2534 		rest -= fragm_sz;
2535 		crs += fragm_sz;
2536 		msg_set_type(&fragm_hdr, FRAGMENT);
2537 	}
2538 	buf_discard(buf);
2539 
2540 	/* Append chain of fragments to send queue & send them */
2541 
2542 	l_ptr->long_msg_seq_no++;
2543 	link_add_chain_to_outqueue(l_ptr, buf_chain, l_ptr->long_msg_seq_no);
2544 	l_ptr->stats.sent_fragments += fragm_no;
2545 	l_ptr->stats.sent_fragmented++;
2546 	tipc_link_push_queue(l_ptr);
2547 
2548 	return dsz;
2549 }
2550 
2551 /*
2552  * A pending message being re-assembled must store certain values
2553  * to handle subsequent fragments correctly. The following functions
2554  * help storing these values in unused, available fields in the
2555  * pending message. This makes dynamic memory allocation unnecessary.
2556  */
2557 
2558 static void set_long_msg_seqno(struct sk_buff *buf, u32 seqno)
2559 {
2560 	msg_set_seqno(buf_msg(buf), seqno);
2561 }
2562 
2563 static u32 get_fragm_size(struct sk_buff *buf)
2564 {
2565 	return msg_ack(buf_msg(buf));
2566 }
2567 
2568 static void set_fragm_size(struct sk_buff *buf, u32 sz)
2569 {
2570 	msg_set_ack(buf_msg(buf), sz);
2571 }
2572 
2573 static u32 get_expected_frags(struct sk_buff *buf)
2574 {
2575 	return msg_bcast_ack(buf_msg(buf));
2576 }
2577 
2578 static void set_expected_frags(struct sk_buff *buf, u32 exp)
2579 {
2580 	msg_set_bcast_ack(buf_msg(buf), exp);
2581 }
2582 
2583 static u32 get_timer_cnt(struct sk_buff *buf)
2584 {
2585 	return msg_reroute_cnt(buf_msg(buf));
2586 }
2587 
2588 static void incr_timer_cnt(struct sk_buff *buf)
2589 {
2590 	msg_incr_reroute_cnt(buf_msg(buf));
2591 }
2592 
2593 /*
2594  * tipc_link_recv_fragment(): Called with node lock on. Returns
2595  * the reassembled buffer if message is complete.
2596  */
2597 int tipc_link_recv_fragment(struct sk_buff **pending, struct sk_buff **fb,
2598 			    struct tipc_msg **m)
2599 {
2600 	struct sk_buff *prev = NULL;
2601 	struct sk_buff *fbuf = *fb;
2602 	struct tipc_msg *fragm = buf_msg(fbuf);
2603 	struct sk_buff *pbuf = *pending;
2604 	u32 long_msg_seq_no = msg_long_msgno(fragm);
2605 
2606 	*fb = NULL;
2607 
2608 	/* Is there an incomplete message waiting for this fragment? */
2609 
2610 	while (pbuf && ((buf_seqno(pbuf) != long_msg_seq_no) ||
2611 			(msg_orignode(fragm) != msg_orignode(buf_msg(pbuf))))) {
2612 		prev = pbuf;
2613 		pbuf = pbuf->next;
2614 	}
2615 
2616 	if (!pbuf && (msg_type(fragm) == FIRST_FRAGMENT)) {
2617 		struct tipc_msg *imsg = (struct tipc_msg *)msg_data(fragm);
2618 		u32 msg_sz = msg_size(imsg);
2619 		u32 fragm_sz = msg_data_sz(fragm);
2620 		u32 exp_fragm_cnt = msg_sz/fragm_sz + !!(msg_sz % fragm_sz);
2621 		u32 max =  TIPC_MAX_USER_MSG_SIZE + NAMED_H_SIZE;
2622 		if (msg_type(imsg) == TIPC_MCAST_MSG)
2623 			max = TIPC_MAX_USER_MSG_SIZE + MCAST_H_SIZE;
2624 		if (msg_size(imsg) > max) {
2625 			buf_discard(fbuf);
2626 			return 0;
2627 		}
2628 		pbuf = tipc_buf_acquire(msg_size(imsg));
2629 		if (pbuf != NULL) {
2630 			pbuf->next = *pending;
2631 			*pending = pbuf;
2632 			skb_copy_to_linear_data(pbuf, imsg,
2633 						msg_data_sz(fragm));
2634 			/*  Prepare buffer for subsequent fragments. */
2635 
2636 			set_long_msg_seqno(pbuf, long_msg_seq_no);
2637 			set_fragm_size(pbuf, fragm_sz);
2638 			set_expected_frags(pbuf, exp_fragm_cnt - 1);
2639 		} else {
2640 			dbg("Link unable to reassemble fragmented message\n");
2641 			buf_discard(fbuf);
2642 			return -1;
2643 		}
2644 		buf_discard(fbuf);
2645 		return 0;
2646 	} else if (pbuf && (msg_type(fragm) != FIRST_FRAGMENT)) {
2647 		u32 dsz = msg_data_sz(fragm);
2648 		u32 fsz = get_fragm_size(pbuf);
2649 		u32 crs = ((msg_fragm_no(fragm) - 1) * fsz);
2650 		u32 exp_frags = get_expected_frags(pbuf) - 1;
2651 		skb_copy_to_linear_data_offset(pbuf, crs,
2652 					       msg_data(fragm), dsz);
2653 		buf_discard(fbuf);
2654 
2655 		/* Is message complete? */
2656 
2657 		if (exp_frags == 0) {
2658 			if (prev)
2659 				prev->next = pbuf->next;
2660 			else
2661 				*pending = pbuf->next;
2662 			msg_reset_reroute_cnt(buf_msg(pbuf));
2663 			*fb = pbuf;
2664 			*m = buf_msg(pbuf);
2665 			return 1;
2666 		}
2667 		set_expected_frags(pbuf, exp_frags);
2668 		return 0;
2669 	}
2670 	buf_discard(fbuf);
2671 	return 0;
2672 }
2673 
2674 /**
2675  * link_check_defragm_bufs - flush stale incoming message fragments
2676  * @l_ptr: pointer to link
2677  */
2678 
2679 static void link_check_defragm_bufs(struct tipc_link *l_ptr)
2680 {
2681 	struct sk_buff *prev = NULL;
2682 	struct sk_buff *next = NULL;
2683 	struct sk_buff *buf = l_ptr->defragm_buf;
2684 
2685 	if (!buf)
2686 		return;
2687 	if (!link_working_working(l_ptr))
2688 		return;
2689 	while (buf) {
2690 		u32 cnt = get_timer_cnt(buf);
2691 
2692 		next = buf->next;
2693 		if (cnt < 4) {
2694 			incr_timer_cnt(buf);
2695 			prev = buf;
2696 		} else {
2697 			if (prev)
2698 				prev->next = buf->next;
2699 			else
2700 				l_ptr->defragm_buf = buf->next;
2701 			buf_discard(buf);
2702 		}
2703 		buf = next;
2704 	}
2705 }
2706 
2707 
2708 
2709 static void link_set_supervision_props(struct tipc_link *l_ptr, u32 tolerance)
2710 {
2711 	if ((tolerance < TIPC_MIN_LINK_TOL) || (tolerance > TIPC_MAX_LINK_TOL))
2712 		return;
2713 
2714 	l_ptr->tolerance = tolerance;
2715 	l_ptr->continuity_interval =
2716 		((tolerance / 4) > 500) ? 500 : tolerance / 4;
2717 	l_ptr->abort_limit = tolerance / (l_ptr->continuity_interval / 4);
2718 }
2719 
2720 
2721 void tipc_link_set_queue_limits(struct tipc_link *l_ptr, u32 window)
2722 {
2723 	/* Data messages from this node, inclusive FIRST_FRAGM */
2724 	l_ptr->queue_limit[TIPC_LOW_IMPORTANCE] = window;
2725 	l_ptr->queue_limit[TIPC_MEDIUM_IMPORTANCE] = (window / 3) * 4;
2726 	l_ptr->queue_limit[TIPC_HIGH_IMPORTANCE] = (window / 3) * 5;
2727 	l_ptr->queue_limit[TIPC_CRITICAL_IMPORTANCE] = (window / 3) * 6;
2728 	/* Transiting data messages,inclusive FIRST_FRAGM */
2729 	l_ptr->queue_limit[TIPC_LOW_IMPORTANCE + 4] = 300;
2730 	l_ptr->queue_limit[TIPC_MEDIUM_IMPORTANCE + 4] = 600;
2731 	l_ptr->queue_limit[TIPC_HIGH_IMPORTANCE + 4] = 900;
2732 	l_ptr->queue_limit[TIPC_CRITICAL_IMPORTANCE + 4] = 1200;
2733 	l_ptr->queue_limit[CONN_MANAGER] = 1200;
2734 	l_ptr->queue_limit[CHANGEOVER_PROTOCOL] = 2500;
2735 	l_ptr->queue_limit[NAME_DISTRIBUTOR] = 3000;
2736 	/* FRAGMENT and LAST_FRAGMENT packets */
2737 	l_ptr->queue_limit[MSG_FRAGMENTER] = 4000;
2738 }
2739 
2740 /**
2741  * link_find_link - locate link by name
2742  * @name - ptr to link name string
2743  * @node - ptr to area to be filled with ptr to associated node
2744  *
2745  * Caller must hold 'tipc_net_lock' to ensure node and bearer are not deleted;
2746  * this also prevents link deletion.
2747  *
2748  * Returns pointer to link (or 0 if invalid link name).
2749  */
2750 
2751 static struct tipc_link *link_find_link(const char *name,
2752 					struct tipc_node **node)
2753 {
2754 	struct tipc_link_name link_name_parts;
2755 	struct tipc_bearer *b_ptr;
2756 	struct tipc_link *l_ptr;
2757 
2758 	if (!link_name_validate(name, &link_name_parts))
2759 		return NULL;
2760 
2761 	b_ptr = tipc_bearer_find_interface(link_name_parts.if_local);
2762 	if (!b_ptr)
2763 		return NULL;
2764 
2765 	*node = tipc_node_find(link_name_parts.addr_peer);
2766 	if (!*node)
2767 		return NULL;
2768 
2769 	l_ptr = (*node)->links[b_ptr->identity];
2770 	if (!l_ptr || strcmp(l_ptr->name, name))
2771 		return NULL;
2772 
2773 	return l_ptr;
2774 }
2775 
2776 /**
2777  * link_value_is_valid -- validate proposed link tolerance/priority/window
2778  *
2779  * @cmd - value type (TIPC_CMD_SET_LINK_*)
2780  * @new_value - the new value
2781  *
2782  * Returns 1 if value is within range, 0 if not.
2783  */
2784 
2785 static int link_value_is_valid(u16 cmd, u32 new_value)
2786 {
2787 	switch (cmd) {
2788 	case TIPC_CMD_SET_LINK_TOL:
2789 		return (new_value >= TIPC_MIN_LINK_TOL) &&
2790 			(new_value <= TIPC_MAX_LINK_TOL);
2791 	case TIPC_CMD_SET_LINK_PRI:
2792 		return (new_value <= TIPC_MAX_LINK_PRI);
2793 	case TIPC_CMD_SET_LINK_WINDOW:
2794 		return (new_value >= TIPC_MIN_LINK_WIN) &&
2795 			(new_value <= TIPC_MAX_LINK_WIN);
2796 	}
2797 	return 0;
2798 }
2799 
2800 
2801 /**
2802  * link_cmd_set_value - change priority/tolerance/window for link/bearer/media
2803  * @name - ptr to link, bearer, or media name
2804  * @new_value - new value of link, bearer, or media setting
2805  * @cmd - which link, bearer, or media attribute to set (TIPC_CMD_SET_LINK_*)
2806  *
2807  * Caller must hold 'tipc_net_lock' to ensure link/bearer/media is not deleted.
2808  *
2809  * Returns 0 if value updated and negative value on error.
2810  */
2811 
2812 static int link_cmd_set_value(const char *name, u32 new_value, u16 cmd)
2813 {
2814 	struct tipc_node *node;
2815 	struct tipc_link *l_ptr;
2816 	struct tipc_bearer *b_ptr;
2817 	struct tipc_media *m_ptr;
2818 
2819 	l_ptr = link_find_link(name, &node);
2820 	if (l_ptr) {
2821 		/*
2822 		 * acquire node lock for tipc_link_send_proto_msg().
2823 		 * see "TIPC locking policy" in net.c.
2824 		 */
2825 		tipc_node_lock(node);
2826 		switch (cmd) {
2827 		case TIPC_CMD_SET_LINK_TOL:
2828 			link_set_supervision_props(l_ptr, new_value);
2829 			tipc_link_send_proto_msg(l_ptr,
2830 				STATE_MSG, 0, 0, new_value, 0, 0);
2831 			break;
2832 		case TIPC_CMD_SET_LINK_PRI:
2833 			l_ptr->priority = new_value;
2834 			tipc_link_send_proto_msg(l_ptr,
2835 				STATE_MSG, 0, 0, 0, new_value, 0);
2836 			break;
2837 		case TIPC_CMD_SET_LINK_WINDOW:
2838 			tipc_link_set_queue_limits(l_ptr, new_value);
2839 			break;
2840 		}
2841 		tipc_node_unlock(node);
2842 		return 0;
2843 	}
2844 
2845 	b_ptr = tipc_bearer_find(name);
2846 	if (b_ptr) {
2847 		switch (cmd) {
2848 		case TIPC_CMD_SET_LINK_TOL:
2849 			b_ptr->tolerance = new_value;
2850 			return 0;
2851 		case TIPC_CMD_SET_LINK_PRI:
2852 			b_ptr->priority = new_value;
2853 			return 0;
2854 		case TIPC_CMD_SET_LINK_WINDOW:
2855 			b_ptr->window = new_value;
2856 			return 0;
2857 		}
2858 		return -EINVAL;
2859 	}
2860 
2861 	m_ptr = tipc_media_find(name);
2862 	if (!m_ptr)
2863 		return -ENODEV;
2864 	switch (cmd) {
2865 	case TIPC_CMD_SET_LINK_TOL:
2866 		m_ptr->tolerance = new_value;
2867 		return 0;
2868 	case TIPC_CMD_SET_LINK_PRI:
2869 		m_ptr->priority = new_value;
2870 		return 0;
2871 	case TIPC_CMD_SET_LINK_WINDOW:
2872 		m_ptr->window = new_value;
2873 		return 0;
2874 	}
2875 	return -EINVAL;
2876 }
2877 
2878 struct sk_buff *tipc_link_cmd_config(const void *req_tlv_area, int req_tlv_space,
2879 				     u16 cmd)
2880 {
2881 	struct tipc_link_config *args;
2882 	u32 new_value;
2883 	int res;
2884 
2885 	if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_CONFIG))
2886 		return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2887 
2888 	args = (struct tipc_link_config *)TLV_DATA(req_tlv_area);
2889 	new_value = ntohl(args->value);
2890 
2891 	if (!link_value_is_valid(cmd, new_value))
2892 		return tipc_cfg_reply_error_string(
2893 			"cannot change, value invalid");
2894 
2895 	if (!strcmp(args->name, tipc_bclink_name)) {
2896 		if ((cmd == TIPC_CMD_SET_LINK_WINDOW) &&
2897 		    (tipc_bclink_set_queue_limits(new_value) == 0))
2898 			return tipc_cfg_reply_none();
2899 		return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
2900 						   " (cannot change setting on broadcast link)");
2901 	}
2902 
2903 	read_lock_bh(&tipc_net_lock);
2904 	res = link_cmd_set_value(args->name, new_value, cmd);
2905 	read_unlock_bh(&tipc_net_lock);
2906 	if (res)
2907 		return tipc_cfg_reply_error_string("cannot change link setting");
2908 
2909 	return tipc_cfg_reply_none();
2910 }
2911 
2912 /**
2913  * link_reset_statistics - reset link statistics
2914  * @l_ptr: pointer to link
2915  */
2916 
2917 static void link_reset_statistics(struct tipc_link *l_ptr)
2918 {
2919 	memset(&l_ptr->stats, 0, sizeof(l_ptr->stats));
2920 	l_ptr->stats.sent_info = l_ptr->next_out_no;
2921 	l_ptr->stats.recv_info = l_ptr->next_in_no;
2922 }
2923 
2924 struct sk_buff *tipc_link_cmd_reset_stats(const void *req_tlv_area, int req_tlv_space)
2925 {
2926 	char *link_name;
2927 	struct tipc_link *l_ptr;
2928 	struct tipc_node *node;
2929 
2930 	if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_NAME))
2931 		return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2932 
2933 	link_name = (char *)TLV_DATA(req_tlv_area);
2934 	if (!strcmp(link_name, tipc_bclink_name)) {
2935 		if (tipc_bclink_reset_stats())
2936 			return tipc_cfg_reply_error_string("link not found");
2937 		return tipc_cfg_reply_none();
2938 	}
2939 
2940 	read_lock_bh(&tipc_net_lock);
2941 	l_ptr = link_find_link(link_name, &node);
2942 	if (!l_ptr) {
2943 		read_unlock_bh(&tipc_net_lock);
2944 		return tipc_cfg_reply_error_string("link not found");
2945 	}
2946 
2947 	tipc_node_lock(node);
2948 	link_reset_statistics(l_ptr);
2949 	tipc_node_unlock(node);
2950 	read_unlock_bh(&tipc_net_lock);
2951 	return tipc_cfg_reply_none();
2952 }
2953 
2954 /**
2955  * percent - convert count to a percentage of total (rounding up or down)
2956  */
2957 
2958 static u32 percent(u32 count, u32 total)
2959 {
2960 	return (count * 100 + (total / 2)) / total;
2961 }
2962 
2963 /**
2964  * tipc_link_stats - print link statistics
2965  * @name: link name
2966  * @buf: print buffer area
2967  * @buf_size: size of print buffer area
2968  *
2969  * Returns length of print buffer data string (or 0 if error)
2970  */
2971 
2972 static int tipc_link_stats(const char *name, char *buf, const u32 buf_size)
2973 {
2974 	struct print_buf pb;
2975 	struct tipc_link *l_ptr;
2976 	struct tipc_node *node;
2977 	char *status;
2978 	u32 profile_total = 0;
2979 
2980 	if (!strcmp(name, tipc_bclink_name))
2981 		return tipc_bclink_stats(buf, buf_size);
2982 
2983 	tipc_printbuf_init(&pb, buf, buf_size);
2984 
2985 	read_lock_bh(&tipc_net_lock);
2986 	l_ptr = link_find_link(name, &node);
2987 	if (!l_ptr) {
2988 		read_unlock_bh(&tipc_net_lock);
2989 		return 0;
2990 	}
2991 	tipc_node_lock(node);
2992 
2993 	if (tipc_link_is_active(l_ptr))
2994 		status = "ACTIVE";
2995 	else if (tipc_link_is_up(l_ptr))
2996 		status = "STANDBY";
2997 	else
2998 		status = "DEFUNCT";
2999 	tipc_printf(&pb, "Link <%s>\n"
3000 			 "  %s  MTU:%u  Priority:%u  Tolerance:%u ms"
3001 			 "  Window:%u packets\n",
3002 		    l_ptr->name, status, l_ptr->max_pkt,
3003 		    l_ptr->priority, l_ptr->tolerance, l_ptr->queue_limit[0]);
3004 	tipc_printf(&pb, "  RX packets:%u fragments:%u/%u bundles:%u/%u\n",
3005 		    l_ptr->next_in_no - l_ptr->stats.recv_info,
3006 		    l_ptr->stats.recv_fragments,
3007 		    l_ptr->stats.recv_fragmented,
3008 		    l_ptr->stats.recv_bundles,
3009 		    l_ptr->stats.recv_bundled);
3010 	tipc_printf(&pb, "  TX packets:%u fragments:%u/%u bundles:%u/%u\n",
3011 		    l_ptr->next_out_no - l_ptr->stats.sent_info,
3012 		    l_ptr->stats.sent_fragments,
3013 		    l_ptr->stats.sent_fragmented,
3014 		    l_ptr->stats.sent_bundles,
3015 		    l_ptr->stats.sent_bundled);
3016 	profile_total = l_ptr->stats.msg_length_counts;
3017 	if (!profile_total)
3018 		profile_total = 1;
3019 	tipc_printf(&pb, "  TX profile sample:%u packets  average:%u octets\n"
3020 			 "  0-64:%u%% -256:%u%% -1024:%u%% -4096:%u%% "
3021 			 "-16384:%u%% -32768:%u%% -66000:%u%%\n",
3022 		    l_ptr->stats.msg_length_counts,
3023 		    l_ptr->stats.msg_lengths_total / profile_total,
3024 		    percent(l_ptr->stats.msg_length_profile[0], profile_total),
3025 		    percent(l_ptr->stats.msg_length_profile[1], profile_total),
3026 		    percent(l_ptr->stats.msg_length_profile[2], profile_total),
3027 		    percent(l_ptr->stats.msg_length_profile[3], profile_total),
3028 		    percent(l_ptr->stats.msg_length_profile[4], profile_total),
3029 		    percent(l_ptr->stats.msg_length_profile[5], profile_total),
3030 		    percent(l_ptr->stats.msg_length_profile[6], profile_total));
3031 	tipc_printf(&pb, "  RX states:%u probes:%u naks:%u defs:%u dups:%u\n",
3032 		    l_ptr->stats.recv_states,
3033 		    l_ptr->stats.recv_probes,
3034 		    l_ptr->stats.recv_nacks,
3035 		    l_ptr->stats.deferred_recv,
3036 		    l_ptr->stats.duplicates);
3037 	tipc_printf(&pb, "  TX states:%u probes:%u naks:%u acks:%u dups:%u\n",
3038 		    l_ptr->stats.sent_states,
3039 		    l_ptr->stats.sent_probes,
3040 		    l_ptr->stats.sent_nacks,
3041 		    l_ptr->stats.sent_acks,
3042 		    l_ptr->stats.retransmitted);
3043 	tipc_printf(&pb, "  Congestion bearer:%u link:%u  Send queue max:%u avg:%u\n",
3044 		    l_ptr->stats.bearer_congs,
3045 		    l_ptr->stats.link_congs,
3046 		    l_ptr->stats.max_queue_sz,
3047 		    l_ptr->stats.queue_sz_counts
3048 		    ? (l_ptr->stats.accu_queue_sz / l_ptr->stats.queue_sz_counts)
3049 		    : 0);
3050 
3051 	tipc_node_unlock(node);
3052 	read_unlock_bh(&tipc_net_lock);
3053 	return tipc_printbuf_validate(&pb);
3054 }
3055 
3056 #define MAX_LINK_STATS_INFO 2000
3057 
3058 struct sk_buff *tipc_link_cmd_show_stats(const void *req_tlv_area, int req_tlv_space)
3059 {
3060 	struct sk_buff *buf;
3061 	struct tlv_desc *rep_tlv;
3062 	int str_len;
3063 
3064 	if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_NAME))
3065 		return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
3066 
3067 	buf = tipc_cfg_reply_alloc(TLV_SPACE(MAX_LINK_STATS_INFO));
3068 	if (!buf)
3069 		return NULL;
3070 
3071 	rep_tlv = (struct tlv_desc *)buf->data;
3072 
3073 	str_len = tipc_link_stats((char *)TLV_DATA(req_tlv_area),
3074 				  (char *)TLV_DATA(rep_tlv), MAX_LINK_STATS_INFO);
3075 	if (!str_len) {
3076 		buf_discard(buf);
3077 		return tipc_cfg_reply_error_string("link not found");
3078 	}
3079 
3080 	skb_put(buf, TLV_SPACE(str_len));
3081 	TLV_SET(rep_tlv, TIPC_TLV_ULTRA_STRING, NULL, str_len);
3082 
3083 	return buf;
3084 }
3085 
3086 /**
3087  * tipc_link_get_max_pkt - get maximum packet size to use when sending to destination
3088  * @dest: network address of destination node
3089  * @selector: used to select from set of active links
3090  *
3091  * If no active link can be found, uses default maximum packet size.
3092  */
3093 
3094 u32 tipc_link_get_max_pkt(u32 dest, u32 selector)
3095 {
3096 	struct tipc_node *n_ptr;
3097 	struct tipc_link *l_ptr;
3098 	u32 res = MAX_PKT_DEFAULT;
3099 
3100 	if (dest == tipc_own_addr)
3101 		return MAX_MSG_SIZE;
3102 
3103 	read_lock_bh(&tipc_net_lock);
3104 	n_ptr = tipc_node_find(dest);
3105 	if (n_ptr) {
3106 		tipc_node_lock(n_ptr);
3107 		l_ptr = n_ptr->active_links[selector & 1];
3108 		if (l_ptr)
3109 			res = l_ptr->max_pkt;
3110 		tipc_node_unlock(n_ptr);
3111 	}
3112 	read_unlock_bh(&tipc_net_lock);
3113 	return res;
3114 }
3115 
3116 static void link_print(struct tipc_link *l_ptr, const char *str)
3117 {
3118 	char print_area[256];
3119 	struct print_buf pb;
3120 	struct print_buf *buf = &pb;
3121 
3122 	tipc_printbuf_init(buf, print_area, sizeof(print_area));
3123 
3124 	tipc_printf(buf, str);
3125 	tipc_printf(buf, "Link %x<%s>:",
3126 		    l_ptr->addr, l_ptr->b_ptr->name);
3127 
3128 #ifdef CONFIG_TIPC_DEBUG
3129 	if (link_reset_reset(l_ptr) || link_reset_unknown(l_ptr))
3130 		goto print_state;
3131 
3132 	tipc_printf(buf, ": NXO(%u):", mod(l_ptr->next_out_no));
3133 	tipc_printf(buf, "NXI(%u):", mod(l_ptr->next_in_no));
3134 	tipc_printf(buf, "SQUE");
3135 	if (l_ptr->first_out) {
3136 		tipc_printf(buf, "[%u..", buf_seqno(l_ptr->first_out));
3137 		if (l_ptr->next_out)
3138 			tipc_printf(buf, "%u..", buf_seqno(l_ptr->next_out));
3139 		tipc_printf(buf, "%u]", buf_seqno(l_ptr->last_out));
3140 		if ((mod(buf_seqno(l_ptr->last_out) -
3141 			 buf_seqno(l_ptr->first_out))
3142 		     != (l_ptr->out_queue_size - 1)) ||
3143 		    (l_ptr->last_out->next != NULL)) {
3144 			tipc_printf(buf, "\nSend queue inconsistency\n");
3145 			tipc_printf(buf, "first_out= %p ", l_ptr->first_out);
3146 			tipc_printf(buf, "next_out= %p ", l_ptr->next_out);
3147 			tipc_printf(buf, "last_out= %p ", l_ptr->last_out);
3148 		}
3149 	} else
3150 		tipc_printf(buf, "[]");
3151 	tipc_printf(buf, "SQSIZ(%u)", l_ptr->out_queue_size);
3152 	if (l_ptr->oldest_deferred_in) {
3153 		u32 o = buf_seqno(l_ptr->oldest_deferred_in);
3154 		u32 n = buf_seqno(l_ptr->newest_deferred_in);
3155 		tipc_printf(buf, ":RQUE[%u..%u]", o, n);
3156 		if (l_ptr->deferred_inqueue_sz != mod((n + 1) - o)) {
3157 			tipc_printf(buf, ":RQSIZ(%u)",
3158 				    l_ptr->deferred_inqueue_sz);
3159 		}
3160 	}
3161 print_state:
3162 #endif
3163 
3164 	if (link_working_unknown(l_ptr))
3165 		tipc_printf(buf, ":WU");
3166 	else if (link_reset_reset(l_ptr))
3167 		tipc_printf(buf, ":RR");
3168 	else if (link_reset_unknown(l_ptr))
3169 		tipc_printf(buf, ":RU");
3170 	else if (link_working_working(l_ptr))
3171 		tipc_printf(buf, ":WW");
3172 	tipc_printf(buf, "\n");
3173 
3174 	tipc_printbuf_validate(buf);
3175 	info("%s", print_area);
3176 }
3177 
3178