xref: /linux/net/tipc/link.c (revision cb299ba8b5ef2239429484072fea394cd7581bd7)
1 /*
2  * net/tipc/link.c: TIPC link code
3  *
4  * Copyright (c) 1996-2007, Ericsson AB
5  * Copyright (c) 2004-2007, 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 "dbg.h"
39 #include "link.h"
40 #include "net.h"
41 #include "node.h"
42 #include "port.h"
43 #include "addr.h"
44 #include "node_subscr.h"
45 #include "name_distr.h"
46 #include "bearer.h"
47 #include "name_table.h"
48 #include "discover.h"
49 #include "config.h"
50 #include "bcast.h"
51 
52 
53 /*
54  * Out-of-range value for link session numbers
55  */
56 
57 #define INVALID_SESSION 0x10000
58 
59 /*
60  * Limit for deferred reception queue:
61  */
62 
63 #define DEF_QUEUE_LIMIT 256u
64 
65 /*
66  * Link state events:
67  */
68 
69 #define  STARTING_EVT    856384768	/* link processing trigger */
70 #define  TRAFFIC_MSG_EVT 560815u	/* rx'd ??? */
71 #define  TIMEOUT_EVT     560817u	/* link timer expired */
72 
73 /*
74  * The following two 'message types' is really just implementation
75  * data conveniently stored in the message header.
76  * They must not be considered part of the protocol
77  */
78 #define OPEN_MSG   0
79 #define CLOSED_MSG 1
80 
81 /*
82  * State value stored in 'exp_msg_count'
83  */
84 
85 #define START_CHANGEOVER 100000u
86 
87 /**
88  * struct link_name - deconstructed link name
89  * @addr_local: network address of node at this end
90  * @if_local: name of interface at this end
91  * @addr_peer: network address of node at far end
92  * @if_peer: name of interface at far end
93  */
94 
95 struct link_name {
96 	u32 addr_local;
97 	char if_local[TIPC_MAX_IF_NAME];
98 	u32 addr_peer;
99 	char if_peer[TIPC_MAX_IF_NAME];
100 };
101 
102 static void link_handle_out_of_seq_msg(struct link *l_ptr,
103 				       struct sk_buff *buf);
104 static void link_recv_proto_msg(struct link *l_ptr, struct sk_buff *buf);
105 static int  link_recv_changeover_msg(struct link **l_ptr, struct sk_buff **buf);
106 static void link_set_supervision_props(struct link *l_ptr, u32 tolerance);
107 static int  link_send_sections_long(struct port *sender,
108 				    struct iovec const *msg_sect,
109 				    u32 num_sect, u32 destnode);
110 static void link_check_defragm_bufs(struct link *l_ptr);
111 static void link_state_event(struct link *l_ptr, u32 event);
112 static void link_reset_statistics(struct link *l_ptr);
113 static void link_print(struct link *l_ptr, struct print_buf *buf,
114 		       const char *str);
115 static void link_start(struct link *l_ptr);
116 static int link_send_long_buf(struct link *l_ptr, struct sk_buff *buf);
117 
118 
119 /*
120  * Debugging code used by link routines only
121  *
122  * When debugging link problems on a system that has multiple links,
123  * the standard TIPC debugging routines may not be useful since they
124  * allow the output from multiple links to be intermixed.  For this reason
125  * routines of the form "dbg_link_XXX()" have been created that will capture
126  * debug info into a link's personal print buffer, which can then be dumped
127  * into the TIPC system log (TIPC_LOG) upon request.
128  *
129  * To enable per-link debugging, use LINK_LOG_BUF_SIZE to specify the size
130  * of the print buffer used by each link.  If LINK_LOG_BUF_SIZE is set to 0,
131  * the dbg_link_XXX() routines simply send their output to the standard
132  * debug print buffer (DBG_OUTPUT), if it has been defined; this can be useful
133  * when there is only a single link in the system being debugged.
134  *
135  * Notes:
136  * - When enabled, LINK_LOG_BUF_SIZE should be set to at least TIPC_PB_MIN_SIZE
137  * - "l_ptr" must be valid when using dbg_link_XXX() macros
138  */
139 
140 #define LINK_LOG_BUF_SIZE 0
141 
142 #define dbg_link(fmt, arg...) \
143 	do { \
144 		if (LINK_LOG_BUF_SIZE) \
145 			tipc_printf(&l_ptr->print_buf, fmt, ## arg); \
146 	} while (0)
147 #define dbg_link_msg(msg, txt) \
148 	do { \
149 		if (LINK_LOG_BUF_SIZE) \
150 			tipc_msg_dbg(&l_ptr->print_buf, msg, txt); \
151 	} while (0)
152 #define dbg_link_state(txt) \
153 	do { \
154 		if (LINK_LOG_BUF_SIZE) \
155 			link_print(l_ptr, &l_ptr->print_buf, txt); \
156 	} while (0)
157 #define dbg_link_dump() do { \
158 	if (LINK_LOG_BUF_SIZE) { \
159 		tipc_printf(LOG, "\n\nDumping link <%s>:\n", l_ptr->name); \
160 		tipc_printbuf_move(LOG, &l_ptr->print_buf); \
161 	} \
162 } while (0)
163 
164 static void dbg_print_link(struct link *l_ptr, const char *str)
165 {
166 	if (DBG_OUTPUT != TIPC_NULL)
167 		link_print(l_ptr, DBG_OUTPUT, str);
168 }
169 
170 static void dbg_print_buf_chain(struct sk_buff *root_buf)
171 {
172 	if (DBG_OUTPUT != TIPC_NULL) {
173 		struct sk_buff *buf = root_buf;
174 
175 		while (buf) {
176 			msg_dbg(buf_msg(buf), "In chain: ");
177 			buf = buf->next;
178 		}
179 	}
180 }
181 
182 /*
183  *  Simple link routines
184  */
185 
186 static unsigned int align(unsigned int i)
187 {
188 	return (i + 3) & ~3u;
189 }
190 
191 static void link_init_max_pkt(struct link *l_ptr)
192 {
193 	u32 max_pkt;
194 
195 	max_pkt = (l_ptr->b_ptr->publ.mtu & ~3);
196 	if (max_pkt > MAX_MSG_SIZE)
197 		max_pkt = MAX_MSG_SIZE;
198 
199 	l_ptr->max_pkt_target = max_pkt;
200 	if (l_ptr->max_pkt_target < MAX_PKT_DEFAULT)
201 		l_ptr->max_pkt = l_ptr->max_pkt_target;
202 	else
203 		l_ptr->max_pkt = MAX_PKT_DEFAULT;
204 
205 	l_ptr->max_pkt_probes = 0;
206 }
207 
208 static u32 link_next_sent(struct link *l_ptr)
209 {
210 	if (l_ptr->next_out)
211 		return msg_seqno(buf_msg(l_ptr->next_out));
212 	return mod(l_ptr->next_out_no);
213 }
214 
215 static u32 link_last_sent(struct link *l_ptr)
216 {
217 	return mod(link_next_sent(l_ptr) - 1);
218 }
219 
220 /*
221  *  Simple non-static link routines (i.e. referenced outside this file)
222  */
223 
224 int tipc_link_is_up(struct link *l_ptr)
225 {
226 	if (!l_ptr)
227 		return 0;
228 	return link_working_working(l_ptr) || link_working_unknown(l_ptr);
229 }
230 
231 int tipc_link_is_active(struct link *l_ptr)
232 {
233 	return	(l_ptr->owner->active_links[0] == l_ptr) ||
234 		(l_ptr->owner->active_links[1] == l_ptr);
235 }
236 
237 /**
238  * link_name_validate - validate & (optionally) deconstruct link name
239  * @name - ptr to link name string
240  * @name_parts - ptr to area for link name components (or NULL if not needed)
241  *
242  * Returns 1 if link name is valid, otherwise 0.
243  */
244 
245 static int link_name_validate(const char *name, struct link_name *name_parts)
246 {
247 	char name_copy[TIPC_MAX_LINK_NAME];
248 	char *addr_local;
249 	char *if_local;
250 	char *addr_peer;
251 	char *if_peer;
252 	char dummy;
253 	u32 z_local, c_local, n_local;
254 	u32 z_peer, c_peer, n_peer;
255 	u32 if_local_len;
256 	u32 if_peer_len;
257 
258 	/* copy link name & ensure length is OK */
259 
260 	name_copy[TIPC_MAX_LINK_NAME - 1] = 0;
261 	/* need above in case non-Posix strncpy() doesn't pad with nulls */
262 	strncpy(name_copy, name, TIPC_MAX_LINK_NAME);
263 	if (name_copy[TIPC_MAX_LINK_NAME - 1] != 0)
264 		return 0;
265 
266 	/* ensure all component parts of link name are present */
267 
268 	addr_local = name_copy;
269 	if ((if_local = strchr(addr_local, ':')) == NULL)
270 		return 0;
271 	*(if_local++) = 0;
272 	if ((addr_peer = strchr(if_local, '-')) == NULL)
273 		return 0;
274 	*(addr_peer++) = 0;
275 	if_local_len = addr_peer - if_local;
276 	if ((if_peer = strchr(addr_peer, ':')) == NULL)
277 		return 0;
278 	*(if_peer++) = 0;
279 	if_peer_len = strlen(if_peer) + 1;
280 
281 	/* validate component parts of link name */
282 
283 	if ((sscanf(addr_local, "%u.%u.%u%c",
284 		    &z_local, &c_local, &n_local, &dummy) != 3) ||
285 	    (sscanf(addr_peer, "%u.%u.%u%c",
286 		    &z_peer, &c_peer, &n_peer, &dummy) != 3) ||
287 	    (z_local > 255) || (c_local > 4095) || (n_local > 4095) ||
288 	    (z_peer  > 255) || (c_peer  > 4095) || (n_peer  > 4095) ||
289 	    (if_local_len <= 1) || (if_local_len > TIPC_MAX_IF_NAME) ||
290 	    (if_peer_len  <= 1) || (if_peer_len  > TIPC_MAX_IF_NAME) ||
291 	    (strspn(if_local, tipc_alphabet) != (if_local_len - 1)) ||
292 	    (strspn(if_peer, tipc_alphabet) != (if_peer_len - 1)))
293 		return 0;
294 
295 	/* return link name components, if necessary */
296 
297 	if (name_parts) {
298 		name_parts->addr_local = tipc_addr(z_local, c_local, n_local);
299 		strcpy(name_parts->if_local, if_local);
300 		name_parts->addr_peer = tipc_addr(z_peer, c_peer, n_peer);
301 		strcpy(name_parts->if_peer, if_peer);
302 	}
303 	return 1;
304 }
305 
306 /**
307  * link_timeout - handle expiration of link timer
308  * @l_ptr: pointer to link
309  *
310  * This routine must not grab "tipc_net_lock" to avoid a potential deadlock conflict
311  * with tipc_link_delete().  (There is no risk that the node will be deleted by
312  * another thread because tipc_link_delete() always cancels the link timer before
313  * tipc_node_delete() is called.)
314  */
315 
316 static void link_timeout(struct link *l_ptr)
317 {
318 	tipc_node_lock(l_ptr->owner);
319 
320 	/* update counters used in statistical profiling of send traffic */
321 
322 	l_ptr->stats.accu_queue_sz += l_ptr->out_queue_size;
323 	l_ptr->stats.queue_sz_counts++;
324 
325 	if (l_ptr->out_queue_size > l_ptr->stats.max_queue_sz)
326 		l_ptr->stats.max_queue_sz = l_ptr->out_queue_size;
327 
328 	if (l_ptr->first_out) {
329 		struct tipc_msg *msg = buf_msg(l_ptr->first_out);
330 		u32 length = msg_size(msg);
331 
332 		if ((msg_user(msg) == MSG_FRAGMENTER) &&
333 		    (msg_type(msg) == FIRST_FRAGMENT)) {
334 			length = msg_size(msg_get_wrapped(msg));
335 		}
336 		if (length) {
337 			l_ptr->stats.msg_lengths_total += length;
338 			l_ptr->stats.msg_length_counts++;
339 			if (length <= 64)
340 				l_ptr->stats.msg_length_profile[0]++;
341 			else if (length <= 256)
342 				l_ptr->stats.msg_length_profile[1]++;
343 			else if (length <= 1024)
344 				l_ptr->stats.msg_length_profile[2]++;
345 			else if (length <= 4096)
346 				l_ptr->stats.msg_length_profile[3]++;
347 			else if (length <= 16384)
348 				l_ptr->stats.msg_length_profile[4]++;
349 			else if (length <= 32768)
350 				l_ptr->stats.msg_length_profile[5]++;
351 			else
352 				l_ptr->stats.msg_length_profile[6]++;
353 		}
354 	}
355 
356 	/* do all other link processing performed on a periodic basis */
357 
358 	link_check_defragm_bufs(l_ptr);
359 
360 	link_state_event(l_ptr, TIMEOUT_EVT);
361 
362 	if (l_ptr->next_out)
363 		tipc_link_push_queue(l_ptr);
364 
365 	tipc_node_unlock(l_ptr->owner);
366 }
367 
368 static void link_set_timer(struct link *l_ptr, u32 time)
369 {
370 	k_start_timer(&l_ptr->timer, time);
371 }
372 
373 /**
374  * tipc_link_create - create a new link
375  * @b_ptr: pointer to associated bearer
376  * @peer: network address of node at other end of link
377  * @media_addr: media address to use when sending messages over link
378  *
379  * Returns pointer to link.
380  */
381 
382 struct link *tipc_link_create(struct bearer *b_ptr, const u32 peer,
383 			      const struct tipc_media_addr *media_addr)
384 {
385 	struct link *l_ptr;
386 	struct tipc_msg *msg;
387 	char *if_name;
388 
389 	l_ptr = kzalloc(sizeof(*l_ptr), GFP_ATOMIC);
390 	if (!l_ptr) {
391 		warn("Link creation failed, no memory\n");
392 		return NULL;
393 	}
394 
395 	if (LINK_LOG_BUF_SIZE) {
396 		char *pb = kmalloc(LINK_LOG_BUF_SIZE, GFP_ATOMIC);
397 
398 		if (!pb) {
399 			kfree(l_ptr);
400 			warn("Link creation failed, no memory for print buffer\n");
401 			return NULL;
402 		}
403 		tipc_printbuf_init(&l_ptr->print_buf, pb, LINK_LOG_BUF_SIZE);
404 	}
405 
406 	l_ptr->addr = peer;
407 	if_name = strchr(b_ptr->publ.name, ':') + 1;
408 	sprintf(l_ptr->name, "%u.%u.%u:%s-%u.%u.%u:",
409 		tipc_zone(tipc_own_addr), tipc_cluster(tipc_own_addr),
410 		tipc_node(tipc_own_addr),
411 		if_name,
412 		tipc_zone(peer), tipc_cluster(peer), tipc_node(peer));
413 		/* note: peer i/f is appended to link name by reset/activate */
414 	memcpy(&l_ptr->media_addr, media_addr, sizeof(*media_addr));
415 	l_ptr->checkpoint = 1;
416 	l_ptr->b_ptr = b_ptr;
417 	link_set_supervision_props(l_ptr, b_ptr->media->tolerance);
418 	l_ptr->state = RESET_UNKNOWN;
419 
420 	l_ptr->pmsg = (struct tipc_msg *)&l_ptr->proto_msg;
421 	msg = l_ptr->pmsg;
422 	tipc_msg_init(msg, LINK_PROTOCOL, RESET_MSG, INT_H_SIZE, l_ptr->addr);
423 	msg_set_size(msg, sizeof(l_ptr->proto_msg));
424 	msg_set_session(msg, (tipc_random & 0xffff));
425 	msg_set_bearer_id(msg, b_ptr->identity);
426 	strcpy((char *)msg_data(msg), if_name);
427 
428 	l_ptr->priority = b_ptr->priority;
429 	tipc_link_set_queue_limits(l_ptr, b_ptr->media->window);
430 
431 	link_init_max_pkt(l_ptr);
432 
433 	l_ptr->next_out_no = 1;
434 	INIT_LIST_HEAD(&l_ptr->waiting_ports);
435 
436 	link_reset_statistics(l_ptr);
437 
438 	l_ptr->owner = tipc_node_attach_link(l_ptr);
439 	if (!l_ptr->owner) {
440 		if (LINK_LOG_BUF_SIZE)
441 			kfree(l_ptr->print_buf.buf);
442 		kfree(l_ptr);
443 		return NULL;
444 	}
445 
446 	k_init_timer(&l_ptr->timer, (Handler)link_timeout, (unsigned long)l_ptr);
447 	list_add_tail(&l_ptr->link_list, &b_ptr->links);
448 	tipc_k_signal((Handler)link_start, (unsigned long)l_ptr);
449 
450 	dbg("tipc_link_create(): tolerance = %u,cont intv = %u, abort_limit = %u\n",
451 	    l_ptr->tolerance, l_ptr->continuity_interval, l_ptr->abort_limit);
452 
453 	return l_ptr;
454 }
455 
456 /**
457  * tipc_link_delete - delete a link
458  * @l_ptr: pointer to link
459  *
460  * Note: 'tipc_net_lock' is write_locked, bearer is locked.
461  * This routine must not grab the node lock until after link timer cancellation
462  * to avoid a potential deadlock situation.
463  */
464 
465 void tipc_link_delete(struct link *l_ptr)
466 {
467 	if (!l_ptr) {
468 		err("Attempt to delete non-existent link\n");
469 		return;
470 	}
471 
472 	dbg("tipc_link_delete()\n");
473 
474 	k_cancel_timer(&l_ptr->timer);
475 
476 	tipc_node_lock(l_ptr->owner);
477 	tipc_link_reset(l_ptr);
478 	tipc_node_detach_link(l_ptr->owner, l_ptr);
479 	tipc_link_stop(l_ptr);
480 	list_del_init(&l_ptr->link_list);
481 	if (LINK_LOG_BUF_SIZE)
482 		kfree(l_ptr->print_buf.buf);
483 	tipc_node_unlock(l_ptr->owner);
484 	k_term_timer(&l_ptr->timer);
485 	kfree(l_ptr);
486 }
487 
488 static void link_start(struct link *l_ptr)
489 {
490 	dbg("link_start %x\n", l_ptr);
491 	link_state_event(l_ptr, STARTING_EVT);
492 }
493 
494 /**
495  * link_schedule_port - schedule port for deferred sending
496  * @l_ptr: pointer to link
497  * @origport: reference to sending port
498  * @sz: amount of data to be sent
499  *
500  * Schedules port for renewed sending of messages after link congestion
501  * has abated.
502  */
503 
504 static int link_schedule_port(struct link *l_ptr, u32 origport, u32 sz)
505 {
506 	struct port *p_ptr;
507 
508 	spin_lock_bh(&tipc_port_list_lock);
509 	p_ptr = tipc_port_lock(origport);
510 	if (p_ptr) {
511 		if (!p_ptr->wakeup)
512 			goto exit;
513 		if (!list_empty(&p_ptr->wait_list))
514 			goto exit;
515 		p_ptr->publ.congested = 1;
516 		p_ptr->waiting_pkts = 1 + ((sz - 1) / l_ptr->max_pkt);
517 		list_add_tail(&p_ptr->wait_list, &l_ptr->waiting_ports);
518 		l_ptr->stats.link_congs++;
519 exit:
520 		tipc_port_unlock(p_ptr);
521 	}
522 	spin_unlock_bh(&tipc_port_list_lock);
523 	return -ELINKCONG;
524 }
525 
526 void tipc_link_wakeup_ports(struct link *l_ptr, int all)
527 {
528 	struct port *p_ptr;
529 	struct port *temp_p_ptr;
530 	int win = l_ptr->queue_limit[0] - l_ptr->out_queue_size;
531 
532 	if (all)
533 		win = 100000;
534 	if (win <= 0)
535 		return;
536 	if (!spin_trylock_bh(&tipc_port_list_lock))
537 		return;
538 	if (link_congested(l_ptr))
539 		goto exit;
540 	list_for_each_entry_safe(p_ptr, temp_p_ptr, &l_ptr->waiting_ports,
541 				 wait_list) {
542 		if (win <= 0)
543 			break;
544 		list_del_init(&p_ptr->wait_list);
545 		spin_lock_bh(p_ptr->publ.lock);
546 		p_ptr->publ.congested = 0;
547 		p_ptr->wakeup(&p_ptr->publ);
548 		win -= p_ptr->waiting_pkts;
549 		spin_unlock_bh(p_ptr->publ.lock);
550 	}
551 
552 exit:
553 	spin_unlock_bh(&tipc_port_list_lock);
554 }
555 
556 /**
557  * link_release_outqueue - purge link's outbound message queue
558  * @l_ptr: pointer to link
559  */
560 
561 static void link_release_outqueue(struct link *l_ptr)
562 {
563 	struct sk_buff *buf = l_ptr->first_out;
564 	struct sk_buff *next;
565 
566 	while (buf) {
567 		next = buf->next;
568 		buf_discard(buf);
569 		buf = next;
570 	}
571 	l_ptr->first_out = NULL;
572 	l_ptr->out_queue_size = 0;
573 }
574 
575 /**
576  * tipc_link_reset_fragments - purge link's inbound message fragments queue
577  * @l_ptr: pointer to link
578  */
579 
580 void tipc_link_reset_fragments(struct link *l_ptr)
581 {
582 	struct sk_buff *buf = l_ptr->defragm_buf;
583 	struct sk_buff *next;
584 
585 	while (buf) {
586 		next = buf->next;
587 		buf_discard(buf);
588 		buf = next;
589 	}
590 	l_ptr->defragm_buf = NULL;
591 }
592 
593 /**
594  * tipc_link_stop - purge all inbound and outbound messages associated with link
595  * @l_ptr: pointer to link
596  */
597 
598 void tipc_link_stop(struct link *l_ptr)
599 {
600 	struct sk_buff *buf;
601 	struct sk_buff *next;
602 
603 	buf = l_ptr->oldest_deferred_in;
604 	while (buf) {
605 		next = buf->next;
606 		buf_discard(buf);
607 		buf = next;
608 	}
609 
610 	buf = l_ptr->first_out;
611 	while (buf) {
612 		next = buf->next;
613 		buf_discard(buf);
614 		buf = next;
615 	}
616 
617 	tipc_link_reset_fragments(l_ptr);
618 
619 	buf_discard(l_ptr->proto_msg_queue);
620 	l_ptr->proto_msg_queue = NULL;
621 }
622 
623 /* LINK EVENT CODE IS NOT SUPPORTED AT PRESENT */
624 #define link_send_event(fcn, l_ptr, up) do { } while (0)
625 
626 void tipc_link_reset(struct link *l_ptr)
627 {
628 	struct sk_buff *buf;
629 	u32 prev_state = l_ptr->state;
630 	u32 checkpoint = l_ptr->next_in_no;
631 	int was_active_link = tipc_link_is_active(l_ptr);
632 
633 	msg_set_session(l_ptr->pmsg, ((msg_session(l_ptr->pmsg) + 1) & 0xffff));
634 
635 	/* Link is down, accept any session */
636 	l_ptr->peer_session = INVALID_SESSION;
637 
638 	/* Prepare for max packet size negotiation */
639 	link_init_max_pkt(l_ptr);
640 
641 	l_ptr->state = RESET_UNKNOWN;
642 	dbg_link_state("Resetting Link\n");
643 
644 	if ((prev_state == RESET_UNKNOWN) || (prev_state == RESET_RESET))
645 		return;
646 
647 	tipc_node_link_down(l_ptr->owner, l_ptr);
648 	tipc_bearer_remove_dest(l_ptr->b_ptr, l_ptr->addr);
649 
650 	if (was_active_link && tipc_node_has_active_links(l_ptr->owner) &&
651 	    l_ptr->owner->permit_changeover) {
652 		l_ptr->reset_checkpoint = checkpoint;
653 		l_ptr->exp_msg_count = START_CHANGEOVER;
654 	}
655 
656 	/* Clean up all queues: */
657 
658 	link_release_outqueue(l_ptr);
659 	buf_discard(l_ptr->proto_msg_queue);
660 	l_ptr->proto_msg_queue = NULL;
661 	buf = l_ptr->oldest_deferred_in;
662 	while (buf) {
663 		struct sk_buff *next = buf->next;
664 		buf_discard(buf);
665 		buf = next;
666 	}
667 	if (!list_empty(&l_ptr->waiting_ports))
668 		tipc_link_wakeup_ports(l_ptr, 1);
669 
670 	l_ptr->retransm_queue_head = 0;
671 	l_ptr->retransm_queue_size = 0;
672 	l_ptr->last_out = NULL;
673 	l_ptr->first_out = NULL;
674 	l_ptr->next_out = NULL;
675 	l_ptr->unacked_window = 0;
676 	l_ptr->checkpoint = 1;
677 	l_ptr->next_out_no = 1;
678 	l_ptr->deferred_inqueue_sz = 0;
679 	l_ptr->oldest_deferred_in = NULL;
680 	l_ptr->newest_deferred_in = NULL;
681 	l_ptr->fsm_msg_cnt = 0;
682 	l_ptr->stale_count = 0;
683 	link_reset_statistics(l_ptr);
684 
685 	link_send_event(tipc_cfg_link_event, l_ptr, 0);
686 	if (!in_own_cluster(l_ptr->addr))
687 		link_send_event(tipc_disc_link_event, l_ptr, 0);
688 }
689 
690 
691 static void link_activate(struct link *l_ptr)
692 {
693 	l_ptr->next_in_no = l_ptr->stats.recv_info = 1;
694 	tipc_node_link_up(l_ptr->owner, l_ptr);
695 	tipc_bearer_add_dest(l_ptr->b_ptr, l_ptr->addr);
696 	link_send_event(tipc_cfg_link_event, l_ptr, 1);
697 	if (!in_own_cluster(l_ptr->addr))
698 		link_send_event(tipc_disc_link_event, l_ptr, 1);
699 }
700 
701 /**
702  * link_state_event - link finite state machine
703  * @l_ptr: pointer to link
704  * @event: state machine event to process
705  */
706 
707 static void link_state_event(struct link *l_ptr, unsigned event)
708 {
709 	struct link *other;
710 	u32 cont_intv = l_ptr->continuity_interval;
711 
712 	if (!l_ptr->started && (event != STARTING_EVT))
713 		return;		/* Not yet. */
714 
715 	if (link_blocked(l_ptr)) {
716 		if (event == TIMEOUT_EVT) {
717 			link_set_timer(l_ptr, cont_intv);
718 		}
719 		return;	  /* Changeover going on */
720 	}
721 	dbg_link("STATE_EV: <%s> ", l_ptr->name);
722 
723 	switch (l_ptr->state) {
724 	case WORKING_WORKING:
725 		dbg_link("WW/");
726 		switch (event) {
727 		case TRAFFIC_MSG_EVT:
728 			dbg_link("TRF-");
729 			/* fall through */
730 		case ACTIVATE_MSG:
731 			dbg_link("ACT\n");
732 			break;
733 		case TIMEOUT_EVT:
734 			dbg_link("TIM ");
735 			if (l_ptr->next_in_no != l_ptr->checkpoint) {
736 				l_ptr->checkpoint = l_ptr->next_in_no;
737 				if (tipc_bclink_acks_missing(l_ptr->owner)) {
738 					tipc_link_send_proto_msg(l_ptr, STATE_MSG,
739 								 0, 0, 0, 0, 0);
740 					l_ptr->fsm_msg_cnt++;
741 				} else if (l_ptr->max_pkt < l_ptr->max_pkt_target) {
742 					tipc_link_send_proto_msg(l_ptr, STATE_MSG,
743 								 1, 0, 0, 0, 0);
744 					l_ptr->fsm_msg_cnt++;
745 				}
746 				link_set_timer(l_ptr, cont_intv);
747 				break;
748 			}
749 			dbg_link(" -> WU\n");
750 			l_ptr->state = WORKING_UNKNOWN;
751 			l_ptr->fsm_msg_cnt = 0;
752 			tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
753 			l_ptr->fsm_msg_cnt++;
754 			link_set_timer(l_ptr, cont_intv / 4);
755 			break;
756 		case RESET_MSG:
757 			dbg_link("RES -> RR\n");
758 			info("Resetting link <%s>, requested by peer\n",
759 			     l_ptr->name);
760 			tipc_link_reset(l_ptr);
761 			l_ptr->state = RESET_RESET;
762 			l_ptr->fsm_msg_cnt = 0;
763 			tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
764 			l_ptr->fsm_msg_cnt++;
765 			link_set_timer(l_ptr, cont_intv);
766 			break;
767 		default:
768 			err("Unknown link event %u in WW state\n", event);
769 		}
770 		break;
771 	case WORKING_UNKNOWN:
772 		dbg_link("WU/");
773 		switch (event) {
774 		case TRAFFIC_MSG_EVT:
775 			dbg_link("TRF-");
776 		case ACTIVATE_MSG:
777 			dbg_link("ACT -> WW\n");
778 			l_ptr->state = WORKING_WORKING;
779 			l_ptr->fsm_msg_cnt = 0;
780 			link_set_timer(l_ptr, cont_intv);
781 			break;
782 		case RESET_MSG:
783 			dbg_link("RES -> RR\n");
784 			info("Resetting link <%s>, requested by peer "
785 			     "while probing\n", l_ptr->name);
786 			tipc_link_reset(l_ptr);
787 			l_ptr->state = RESET_RESET;
788 			l_ptr->fsm_msg_cnt = 0;
789 			tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
790 			l_ptr->fsm_msg_cnt++;
791 			link_set_timer(l_ptr, cont_intv);
792 			break;
793 		case TIMEOUT_EVT:
794 			dbg_link("TIM ");
795 			if (l_ptr->next_in_no != l_ptr->checkpoint) {
796 				dbg_link("-> WW\n");
797 				l_ptr->state = WORKING_WORKING;
798 				l_ptr->fsm_msg_cnt = 0;
799 				l_ptr->checkpoint = l_ptr->next_in_no;
800 				if (tipc_bclink_acks_missing(l_ptr->owner)) {
801 					tipc_link_send_proto_msg(l_ptr, STATE_MSG,
802 								 0, 0, 0, 0, 0);
803 					l_ptr->fsm_msg_cnt++;
804 				}
805 				link_set_timer(l_ptr, cont_intv);
806 			} else if (l_ptr->fsm_msg_cnt < l_ptr->abort_limit) {
807 				dbg_link("Probing %u/%u,timer = %u ms)\n",
808 					 l_ptr->fsm_msg_cnt, l_ptr->abort_limit,
809 					 cont_intv / 4);
810 				tipc_link_send_proto_msg(l_ptr, STATE_MSG,
811 							 1, 0, 0, 0, 0);
812 				l_ptr->fsm_msg_cnt++;
813 				link_set_timer(l_ptr, cont_intv / 4);
814 			} else {	/* Link has failed */
815 				dbg_link("-> RU (%u probes unanswered)\n",
816 					 l_ptr->fsm_msg_cnt);
817 				warn("Resetting link <%s>, peer not responding\n",
818 				     l_ptr->name);
819 				tipc_link_reset(l_ptr);
820 				l_ptr->state = RESET_UNKNOWN;
821 				l_ptr->fsm_msg_cnt = 0;
822 				tipc_link_send_proto_msg(l_ptr, RESET_MSG,
823 							 0, 0, 0, 0, 0);
824 				l_ptr->fsm_msg_cnt++;
825 				link_set_timer(l_ptr, cont_intv);
826 			}
827 			break;
828 		default:
829 			err("Unknown link event %u in WU state\n", event);
830 		}
831 		break;
832 	case RESET_UNKNOWN:
833 		dbg_link("RU/");
834 		switch (event) {
835 		case TRAFFIC_MSG_EVT:
836 			dbg_link("TRF-\n");
837 			break;
838 		case ACTIVATE_MSG:
839 			other = l_ptr->owner->active_links[0];
840 			if (other && link_working_unknown(other)) {
841 				dbg_link("ACT\n");
842 				break;
843 			}
844 			dbg_link("ACT -> WW\n");
845 			l_ptr->state = WORKING_WORKING;
846 			l_ptr->fsm_msg_cnt = 0;
847 			link_activate(l_ptr);
848 			tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
849 			l_ptr->fsm_msg_cnt++;
850 			link_set_timer(l_ptr, cont_intv);
851 			break;
852 		case RESET_MSG:
853 			dbg_link("RES\n");
854 			dbg_link(" -> RR\n");
855 			l_ptr->state = RESET_RESET;
856 			l_ptr->fsm_msg_cnt = 0;
857 			tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 1, 0, 0, 0, 0);
858 			l_ptr->fsm_msg_cnt++;
859 			link_set_timer(l_ptr, cont_intv);
860 			break;
861 		case STARTING_EVT:
862 			dbg_link("START-");
863 			l_ptr->started = 1;
864 			/* fall through */
865 		case TIMEOUT_EVT:
866 			dbg_link("TIM\n");
867 			tipc_link_send_proto_msg(l_ptr, RESET_MSG, 0, 0, 0, 0, 0);
868 			l_ptr->fsm_msg_cnt++;
869 			link_set_timer(l_ptr, cont_intv);
870 			break;
871 		default:
872 			err("Unknown link event %u in RU state\n", event);
873 		}
874 		break;
875 	case RESET_RESET:
876 		dbg_link("RR/ ");
877 		switch (event) {
878 		case TRAFFIC_MSG_EVT:
879 			dbg_link("TRF-");
880 			/* fall through */
881 		case ACTIVATE_MSG:
882 			other = l_ptr->owner->active_links[0];
883 			if (other && link_working_unknown(other)) {
884 				dbg_link("ACT\n");
885 				break;
886 			}
887 			dbg_link("ACT -> WW\n");
888 			l_ptr->state = WORKING_WORKING;
889 			l_ptr->fsm_msg_cnt = 0;
890 			link_activate(l_ptr);
891 			tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
892 			l_ptr->fsm_msg_cnt++;
893 			link_set_timer(l_ptr, cont_intv);
894 			break;
895 		case RESET_MSG:
896 			dbg_link("RES\n");
897 			break;
898 		case TIMEOUT_EVT:
899 			dbg_link("TIM\n");
900 			tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
901 			l_ptr->fsm_msg_cnt++;
902 			link_set_timer(l_ptr, cont_intv);
903 			dbg_link("fsm_msg_cnt %u\n", l_ptr->fsm_msg_cnt);
904 			break;
905 		default:
906 			err("Unknown link event %u in RR state\n", event);
907 		}
908 		break;
909 	default:
910 		err("Unknown link state %u/%u\n", l_ptr->state, event);
911 	}
912 }
913 
914 /*
915  * link_bundle_buf(): Append contents of a buffer to
916  * the tail of an existing one.
917  */
918 
919 static int link_bundle_buf(struct link *l_ptr,
920 			   struct sk_buff *bundler,
921 			   struct sk_buff *buf)
922 {
923 	struct tipc_msg *bundler_msg = buf_msg(bundler);
924 	struct tipc_msg *msg = buf_msg(buf);
925 	u32 size = msg_size(msg);
926 	u32 bundle_size = msg_size(bundler_msg);
927 	u32 to_pos = align(bundle_size);
928 	u32 pad = to_pos - bundle_size;
929 
930 	if (msg_user(bundler_msg) != MSG_BUNDLER)
931 		return 0;
932 	if (msg_type(bundler_msg) != OPEN_MSG)
933 		return 0;
934 	if (skb_tailroom(bundler) < (pad + size))
935 		return 0;
936 	if (l_ptr->max_pkt < (to_pos + size))
937 		return 0;
938 
939 	skb_put(bundler, pad + size);
940 	skb_copy_to_linear_data_offset(bundler, to_pos, buf->data, size);
941 	msg_set_size(bundler_msg, to_pos + size);
942 	msg_set_msgcnt(bundler_msg, msg_msgcnt(bundler_msg) + 1);
943 	dbg("Packed msg # %u(%u octets) into pos %u in buf(#%u)\n",
944 	    msg_msgcnt(bundler_msg), size, to_pos, msg_seqno(bundler_msg));
945 	msg_dbg(msg, "PACKD:");
946 	buf_discard(buf);
947 	l_ptr->stats.sent_bundled++;
948 	return 1;
949 }
950 
951 static void link_add_to_outqueue(struct link *l_ptr,
952 				 struct sk_buff *buf,
953 				 struct tipc_msg *msg)
954 {
955 	u32 ack = mod(l_ptr->next_in_no - 1);
956 	u32 seqno = mod(l_ptr->next_out_no++);
957 
958 	msg_set_word(msg, 2, ((ack << 16) | seqno));
959 	msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
960 	buf->next = NULL;
961 	if (l_ptr->first_out) {
962 		l_ptr->last_out->next = buf;
963 		l_ptr->last_out = buf;
964 	} else
965 		l_ptr->first_out = l_ptr->last_out = buf;
966 	l_ptr->out_queue_size++;
967 }
968 
969 /*
970  * tipc_link_send_buf() is the 'full path' for messages, called from
971  * inside TIPC when the 'fast path' in tipc_send_buf
972  * has failed, and from link_send()
973  */
974 
975 int tipc_link_send_buf(struct link *l_ptr, struct sk_buff *buf)
976 {
977 	struct tipc_msg *msg = buf_msg(buf);
978 	u32 size = msg_size(msg);
979 	u32 dsz = msg_data_sz(msg);
980 	u32 queue_size = l_ptr->out_queue_size;
981 	u32 imp = tipc_msg_tot_importance(msg);
982 	u32 queue_limit = l_ptr->queue_limit[imp];
983 	u32 max_packet = l_ptr->max_pkt;
984 
985 	msg_set_prevnode(msg, tipc_own_addr);	/* If routed message */
986 
987 	/* Match msg importance against queue limits: */
988 
989 	if (unlikely(queue_size >= queue_limit)) {
990 		if (imp <= TIPC_CRITICAL_IMPORTANCE) {
991 			return link_schedule_port(l_ptr, msg_origport(msg),
992 						  size);
993 		}
994 		msg_dbg(msg, "TIPC: Congestion, throwing away\n");
995 		buf_discard(buf);
996 		if (imp > CONN_MANAGER) {
997 			warn("Resetting link <%s>, send queue full", l_ptr->name);
998 			tipc_link_reset(l_ptr);
999 		}
1000 		return dsz;
1001 	}
1002 
1003 	/* Fragmentation needed ? */
1004 
1005 	if (size > max_packet)
1006 		return link_send_long_buf(l_ptr, buf);
1007 
1008 	/* Packet can be queued or sent: */
1009 
1010 	if (queue_size > l_ptr->stats.max_queue_sz)
1011 		l_ptr->stats.max_queue_sz = queue_size;
1012 
1013 	if (likely(!tipc_bearer_congested(l_ptr->b_ptr, l_ptr) &&
1014 		   !link_congested(l_ptr))) {
1015 		link_add_to_outqueue(l_ptr, buf, msg);
1016 
1017 		if (likely(tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr))) {
1018 			l_ptr->unacked_window = 0;
1019 		} else {
1020 			tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
1021 			l_ptr->stats.bearer_congs++;
1022 			l_ptr->next_out = buf;
1023 		}
1024 		return dsz;
1025 	}
1026 	/* Congestion: can message be bundled ?: */
1027 
1028 	if ((msg_user(msg) != CHANGEOVER_PROTOCOL) &&
1029 	    (msg_user(msg) != MSG_FRAGMENTER)) {
1030 
1031 		/* Try adding message to an existing bundle */
1032 
1033 		if (l_ptr->next_out &&
1034 		    link_bundle_buf(l_ptr, l_ptr->last_out, buf)) {
1035 			tipc_bearer_resolve_congestion(l_ptr->b_ptr, l_ptr);
1036 			return dsz;
1037 		}
1038 
1039 		/* Try creating a new bundle */
1040 
1041 		if (size <= max_packet * 2 / 3) {
1042 			struct sk_buff *bundler = tipc_buf_acquire(max_packet);
1043 			struct tipc_msg bundler_hdr;
1044 
1045 			if (bundler) {
1046 				tipc_msg_init(&bundler_hdr, MSG_BUNDLER, OPEN_MSG,
1047 					 INT_H_SIZE, l_ptr->addr);
1048 				skb_copy_to_linear_data(bundler, &bundler_hdr,
1049 							INT_H_SIZE);
1050 				skb_trim(bundler, INT_H_SIZE);
1051 				link_bundle_buf(l_ptr, bundler, buf);
1052 				buf = bundler;
1053 				msg = buf_msg(buf);
1054 				l_ptr->stats.sent_bundles++;
1055 			}
1056 		}
1057 	}
1058 	if (!l_ptr->next_out)
1059 		l_ptr->next_out = buf;
1060 	link_add_to_outqueue(l_ptr, buf, msg);
1061 	tipc_bearer_resolve_congestion(l_ptr->b_ptr, l_ptr);
1062 	return dsz;
1063 }
1064 
1065 /*
1066  * tipc_link_send(): same as tipc_link_send_buf(), but the link to use has
1067  * not been selected yet, and the the owner node is not locked
1068  * Called by TIPC internal users, e.g. the name distributor
1069  */
1070 
1071 int tipc_link_send(struct sk_buff *buf, u32 dest, u32 selector)
1072 {
1073 	struct link *l_ptr;
1074 	struct tipc_node *n_ptr;
1075 	int res = -ELINKCONG;
1076 
1077 	read_lock_bh(&tipc_net_lock);
1078 	n_ptr = tipc_node_select(dest, selector);
1079 	if (n_ptr) {
1080 		tipc_node_lock(n_ptr);
1081 		l_ptr = n_ptr->active_links[selector & 1];
1082 		if (l_ptr) {
1083 			dbg("tipc_link_send: found link %x for dest %x\n", l_ptr, dest);
1084 			res = tipc_link_send_buf(l_ptr, buf);
1085 		} else {
1086 			dbg("Attempt to send msg to unreachable node:\n");
1087 			msg_dbg(buf_msg(buf),">>>");
1088 			buf_discard(buf);
1089 		}
1090 		tipc_node_unlock(n_ptr);
1091 	} else {
1092 		dbg("Attempt to send msg to unknown node:\n");
1093 		msg_dbg(buf_msg(buf),">>>");
1094 		buf_discard(buf);
1095 	}
1096 	read_unlock_bh(&tipc_net_lock);
1097 	return res;
1098 }
1099 
1100 /*
1101  * link_send_buf_fast: Entry for data messages where the
1102  * destination link is known and the header is complete,
1103  * inclusive total message length. Very time critical.
1104  * Link is locked. Returns user data length.
1105  */
1106 
1107 static int link_send_buf_fast(struct link *l_ptr, struct sk_buff *buf,
1108 			      u32 *used_max_pkt)
1109 {
1110 	struct tipc_msg *msg = buf_msg(buf);
1111 	int res = msg_data_sz(msg);
1112 
1113 	if (likely(!link_congested(l_ptr))) {
1114 		if (likely(msg_size(msg) <= l_ptr->max_pkt)) {
1115 			if (likely(list_empty(&l_ptr->b_ptr->cong_links))) {
1116 				link_add_to_outqueue(l_ptr, buf, msg);
1117 				if (likely(tipc_bearer_send(l_ptr->b_ptr, buf,
1118 							    &l_ptr->media_addr))) {
1119 					l_ptr->unacked_window = 0;
1120 					msg_dbg(msg,"SENT_FAST:");
1121 					return res;
1122 				}
1123 				dbg("failed sent fast...\n");
1124 				tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
1125 				l_ptr->stats.bearer_congs++;
1126 				l_ptr->next_out = buf;
1127 				return res;
1128 			}
1129 		}
1130 		else
1131 			*used_max_pkt = l_ptr->max_pkt;
1132 	}
1133 	return tipc_link_send_buf(l_ptr, buf);  /* All other cases */
1134 }
1135 
1136 /*
1137  * tipc_send_buf_fast: Entry for data messages where the
1138  * destination node is known and the header is complete,
1139  * inclusive total message length.
1140  * Returns user data length.
1141  */
1142 int tipc_send_buf_fast(struct sk_buff *buf, u32 destnode)
1143 {
1144 	struct link *l_ptr;
1145 	struct tipc_node *n_ptr;
1146 	int res;
1147 	u32 selector = msg_origport(buf_msg(buf)) & 1;
1148 	u32 dummy;
1149 
1150 	if (destnode == tipc_own_addr)
1151 		return tipc_port_recv_msg(buf);
1152 
1153 	read_lock_bh(&tipc_net_lock);
1154 	n_ptr = tipc_node_select(destnode, selector);
1155 	if (likely(n_ptr)) {
1156 		tipc_node_lock(n_ptr);
1157 		l_ptr = n_ptr->active_links[selector];
1158 		dbg("send_fast: buf %x selected %x, destnode = %x\n",
1159 		    buf, l_ptr, destnode);
1160 		if (likely(l_ptr)) {
1161 			res = link_send_buf_fast(l_ptr, buf, &dummy);
1162 			tipc_node_unlock(n_ptr);
1163 			read_unlock_bh(&tipc_net_lock);
1164 			return res;
1165 		}
1166 		tipc_node_unlock(n_ptr);
1167 	}
1168 	read_unlock_bh(&tipc_net_lock);
1169 	res = msg_data_sz(buf_msg(buf));
1170 	tipc_reject_msg(buf, TIPC_ERR_NO_NODE);
1171 	return res;
1172 }
1173 
1174 
1175 /*
1176  * tipc_link_send_sections_fast: Entry for messages where the
1177  * destination processor is known and the header is complete,
1178  * except for total message length.
1179  * Returns user data length or errno.
1180  */
1181 int tipc_link_send_sections_fast(struct port *sender,
1182 				 struct iovec const *msg_sect,
1183 				 const u32 num_sect,
1184 				 u32 destaddr)
1185 {
1186 	struct tipc_msg *hdr = &sender->publ.phdr;
1187 	struct link *l_ptr;
1188 	struct sk_buff *buf;
1189 	struct tipc_node *node;
1190 	int res;
1191 	u32 selector = msg_origport(hdr) & 1;
1192 
1193 again:
1194 	/*
1195 	 * Try building message using port's max_pkt hint.
1196 	 * (Must not hold any locks while building message.)
1197 	 */
1198 
1199 	res = tipc_msg_build(hdr, msg_sect, num_sect, sender->publ.max_pkt,
1200 			!sender->user_port, &buf);
1201 
1202 	read_lock_bh(&tipc_net_lock);
1203 	node = tipc_node_select(destaddr, selector);
1204 	if (likely(node)) {
1205 		tipc_node_lock(node);
1206 		l_ptr = node->active_links[selector];
1207 		if (likely(l_ptr)) {
1208 			if (likely(buf)) {
1209 				res = link_send_buf_fast(l_ptr, buf,
1210 							 &sender->publ.max_pkt);
1211 				if (unlikely(res < 0))
1212 					buf_discard(buf);
1213 exit:
1214 				tipc_node_unlock(node);
1215 				read_unlock_bh(&tipc_net_lock);
1216 				return res;
1217 			}
1218 
1219 			/* Exit if build request was invalid */
1220 
1221 			if (unlikely(res < 0))
1222 				goto exit;
1223 
1224 			/* Exit if link (or bearer) is congested */
1225 
1226 			if (link_congested(l_ptr) ||
1227 			    !list_empty(&l_ptr->b_ptr->cong_links)) {
1228 				res = link_schedule_port(l_ptr,
1229 							 sender->publ.ref, res);
1230 				goto exit;
1231 			}
1232 
1233 			/*
1234 			 * Message size exceeds max_pkt hint; update hint,
1235 			 * then re-try fast path or fragment the message
1236 			 */
1237 
1238 			sender->publ.max_pkt = l_ptr->max_pkt;
1239 			tipc_node_unlock(node);
1240 			read_unlock_bh(&tipc_net_lock);
1241 
1242 
1243 			if ((msg_hdr_sz(hdr) + res) <= sender->publ.max_pkt)
1244 				goto again;
1245 
1246 			return link_send_sections_long(sender, msg_sect,
1247 						       num_sect, destaddr);
1248 		}
1249 		tipc_node_unlock(node);
1250 	}
1251 	read_unlock_bh(&tipc_net_lock);
1252 
1253 	/* Couldn't find a link to the destination node */
1254 
1255 	if (buf)
1256 		return tipc_reject_msg(buf, TIPC_ERR_NO_NODE);
1257 	if (res >= 0)
1258 		return tipc_port_reject_sections(sender, hdr, msg_sect, num_sect,
1259 						 TIPC_ERR_NO_NODE);
1260 	return res;
1261 }
1262 
1263 /*
1264  * link_send_sections_long(): Entry for long messages where the
1265  * destination node is known and the header is complete,
1266  * inclusive total message length.
1267  * Link and bearer congestion status have been checked to be ok,
1268  * and are ignored if they change.
1269  *
1270  * Note that fragments do not use the full link MTU so that they won't have
1271  * to undergo refragmentation if link changeover causes them to be sent
1272  * over another link with an additional tunnel header added as prefix.
1273  * (Refragmentation will still occur if the other link has a smaller MTU.)
1274  *
1275  * Returns user data length or errno.
1276  */
1277 static int link_send_sections_long(struct port *sender,
1278 				   struct iovec const *msg_sect,
1279 				   u32 num_sect,
1280 				   u32 destaddr)
1281 {
1282 	struct link *l_ptr;
1283 	struct tipc_node *node;
1284 	struct tipc_msg *hdr = &sender->publ.phdr;
1285 	u32 dsz = msg_data_sz(hdr);
1286 	u32 max_pkt,fragm_sz,rest;
1287 	struct tipc_msg fragm_hdr;
1288 	struct sk_buff *buf,*buf_chain,*prev;
1289 	u32 fragm_crs,fragm_rest,hsz,sect_rest;
1290 	const unchar *sect_crs;
1291 	int curr_sect;
1292 	u32 fragm_no;
1293 
1294 again:
1295 	fragm_no = 1;
1296 	max_pkt = sender->publ.max_pkt - INT_H_SIZE;
1297 		/* leave room for tunnel header in case of link changeover */
1298 	fragm_sz = max_pkt - INT_H_SIZE;
1299 		/* leave room for fragmentation header in each fragment */
1300 	rest = dsz;
1301 	fragm_crs = 0;
1302 	fragm_rest = 0;
1303 	sect_rest = 0;
1304 	sect_crs = NULL;
1305 	curr_sect = -1;
1306 
1307 	/* Prepare reusable fragment header: */
1308 
1309 	msg_dbg(hdr, ">FRAGMENTING>");
1310 	tipc_msg_init(&fragm_hdr, MSG_FRAGMENTER, FIRST_FRAGMENT,
1311 		 INT_H_SIZE, msg_destnode(hdr));
1312 	msg_set_link_selector(&fragm_hdr, sender->publ.ref);
1313 	msg_set_size(&fragm_hdr, max_pkt);
1314 	msg_set_fragm_no(&fragm_hdr, 1);
1315 
1316 	/* Prepare header of first fragment: */
1317 
1318 	buf_chain = buf = tipc_buf_acquire(max_pkt);
1319 	if (!buf)
1320 		return -ENOMEM;
1321 	buf->next = NULL;
1322 	skb_copy_to_linear_data(buf, &fragm_hdr, INT_H_SIZE);
1323 	hsz = msg_hdr_sz(hdr);
1324 	skb_copy_to_linear_data_offset(buf, INT_H_SIZE, hdr, hsz);
1325 	msg_dbg(buf_msg(buf), ">BUILD>");
1326 
1327 	/* Chop up message: */
1328 
1329 	fragm_crs = INT_H_SIZE + hsz;
1330 	fragm_rest = fragm_sz - hsz;
1331 
1332 	do {		/* For all sections */
1333 		u32 sz;
1334 
1335 		if (!sect_rest) {
1336 			sect_rest = msg_sect[++curr_sect].iov_len;
1337 			sect_crs = (const unchar *)msg_sect[curr_sect].iov_base;
1338 		}
1339 
1340 		if (sect_rest < fragm_rest)
1341 			sz = sect_rest;
1342 		else
1343 			sz = fragm_rest;
1344 
1345 		if (likely(!sender->user_port)) {
1346 			if (copy_from_user(buf->data + fragm_crs, sect_crs, sz)) {
1347 error:
1348 				for (; buf_chain; buf_chain = buf) {
1349 					buf = buf_chain->next;
1350 					buf_discard(buf_chain);
1351 				}
1352 				return -EFAULT;
1353 			}
1354 		} else
1355 			skb_copy_to_linear_data_offset(buf, fragm_crs,
1356 						       sect_crs, sz);
1357 		sect_crs += sz;
1358 		sect_rest -= sz;
1359 		fragm_crs += sz;
1360 		fragm_rest -= sz;
1361 		rest -= sz;
1362 
1363 		if (!fragm_rest && rest) {
1364 
1365 			/* Initiate new fragment: */
1366 			if (rest <= fragm_sz) {
1367 				fragm_sz = rest;
1368 				msg_set_type(&fragm_hdr,LAST_FRAGMENT);
1369 			} else {
1370 				msg_set_type(&fragm_hdr, FRAGMENT);
1371 			}
1372 			msg_set_size(&fragm_hdr, fragm_sz + INT_H_SIZE);
1373 			msg_set_fragm_no(&fragm_hdr, ++fragm_no);
1374 			prev = buf;
1375 			buf = tipc_buf_acquire(fragm_sz + INT_H_SIZE);
1376 			if (!buf)
1377 				goto error;
1378 
1379 			buf->next = NULL;
1380 			prev->next = buf;
1381 			skb_copy_to_linear_data(buf, &fragm_hdr, INT_H_SIZE);
1382 			fragm_crs = INT_H_SIZE;
1383 			fragm_rest = fragm_sz;
1384 			msg_dbg(buf_msg(buf),"  >BUILD>");
1385 		}
1386 	}
1387 	while (rest > 0);
1388 
1389 	/*
1390 	 * Now we have a buffer chain. Select a link and check
1391 	 * that packet size is still OK
1392 	 */
1393 	node = tipc_node_select(destaddr, sender->publ.ref & 1);
1394 	if (likely(node)) {
1395 		tipc_node_lock(node);
1396 		l_ptr = node->active_links[sender->publ.ref & 1];
1397 		if (!l_ptr) {
1398 			tipc_node_unlock(node);
1399 			goto reject;
1400 		}
1401 		if (l_ptr->max_pkt < max_pkt) {
1402 			sender->publ.max_pkt = l_ptr->max_pkt;
1403 			tipc_node_unlock(node);
1404 			for (; buf_chain; buf_chain = buf) {
1405 				buf = buf_chain->next;
1406 				buf_discard(buf_chain);
1407 			}
1408 			goto again;
1409 		}
1410 	} else {
1411 reject:
1412 		for (; buf_chain; buf_chain = buf) {
1413 			buf = buf_chain->next;
1414 			buf_discard(buf_chain);
1415 		}
1416 		return tipc_port_reject_sections(sender, hdr, msg_sect, num_sect,
1417 						 TIPC_ERR_NO_NODE);
1418 	}
1419 
1420 	/* Append whole chain to send queue: */
1421 
1422 	buf = buf_chain;
1423 	l_ptr->long_msg_seq_no = mod(l_ptr->long_msg_seq_no + 1);
1424 	if (!l_ptr->next_out)
1425 		l_ptr->next_out = buf_chain;
1426 	l_ptr->stats.sent_fragmented++;
1427 	while (buf) {
1428 		struct sk_buff *next = buf->next;
1429 		struct tipc_msg *msg = buf_msg(buf);
1430 
1431 		l_ptr->stats.sent_fragments++;
1432 		msg_set_long_msgno(msg, l_ptr->long_msg_seq_no);
1433 		link_add_to_outqueue(l_ptr, buf, msg);
1434 		msg_dbg(msg, ">ADD>");
1435 		buf = next;
1436 	}
1437 
1438 	/* Send it, if possible: */
1439 
1440 	tipc_link_push_queue(l_ptr);
1441 	tipc_node_unlock(node);
1442 	return dsz;
1443 }
1444 
1445 /*
1446  * tipc_link_push_packet: Push one unsent packet to the media
1447  */
1448 u32 tipc_link_push_packet(struct link *l_ptr)
1449 {
1450 	struct sk_buff *buf = l_ptr->first_out;
1451 	u32 r_q_size = l_ptr->retransm_queue_size;
1452 	u32 r_q_head = l_ptr->retransm_queue_head;
1453 
1454 	/* Step to position where retransmission failed, if any,    */
1455 	/* consider that buffers may have been released in meantime */
1456 
1457 	if (r_q_size && buf) {
1458 		u32 last = lesser(mod(r_q_head + r_q_size),
1459 				  link_last_sent(l_ptr));
1460 		u32 first = msg_seqno(buf_msg(buf));
1461 
1462 		while (buf && less(first, r_q_head)) {
1463 			first = mod(first + 1);
1464 			buf = buf->next;
1465 		}
1466 		l_ptr->retransm_queue_head = r_q_head = first;
1467 		l_ptr->retransm_queue_size = r_q_size = mod(last - first);
1468 	}
1469 
1470 	/* Continue retransmission now, if there is anything: */
1471 
1472 	if (r_q_size && buf) {
1473 		msg_set_ack(buf_msg(buf), mod(l_ptr->next_in_no - 1));
1474 		msg_set_bcast_ack(buf_msg(buf), l_ptr->owner->bclink.last_in);
1475 		if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1476 			msg_dbg(buf_msg(buf), ">DEF-RETR>");
1477 			l_ptr->retransm_queue_head = mod(++r_q_head);
1478 			l_ptr->retransm_queue_size = --r_q_size;
1479 			l_ptr->stats.retransmitted++;
1480 			return 0;
1481 		} else {
1482 			l_ptr->stats.bearer_congs++;
1483 			msg_dbg(buf_msg(buf), "|>DEF-RETR>");
1484 			return PUSH_FAILED;
1485 		}
1486 	}
1487 
1488 	/* Send deferred protocol message, if any: */
1489 
1490 	buf = l_ptr->proto_msg_queue;
1491 	if (buf) {
1492 		msg_set_ack(buf_msg(buf), mod(l_ptr->next_in_no - 1));
1493 		msg_set_bcast_ack(buf_msg(buf),l_ptr->owner->bclink.last_in);
1494 		if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1495 			msg_dbg(buf_msg(buf), ">DEF-PROT>");
1496 			l_ptr->unacked_window = 0;
1497 			buf_discard(buf);
1498 			l_ptr->proto_msg_queue = NULL;
1499 			return 0;
1500 		} else {
1501 			msg_dbg(buf_msg(buf), "|>DEF-PROT>");
1502 			l_ptr->stats.bearer_congs++;
1503 			return PUSH_FAILED;
1504 		}
1505 	}
1506 
1507 	/* Send one deferred data message, if send window not full: */
1508 
1509 	buf = l_ptr->next_out;
1510 	if (buf) {
1511 		struct tipc_msg *msg = buf_msg(buf);
1512 		u32 next = msg_seqno(msg);
1513 		u32 first = msg_seqno(buf_msg(l_ptr->first_out));
1514 
1515 		if (mod(next - first) < l_ptr->queue_limit[0]) {
1516 			msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1517 			msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1518 			if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1519 				if (msg_user(msg) == MSG_BUNDLER)
1520 					msg_set_type(msg, CLOSED_MSG);
1521 				msg_dbg(msg, ">PUSH-DATA>");
1522 				l_ptr->next_out = buf->next;
1523 				return 0;
1524 			} else {
1525 				msg_dbg(msg, "|PUSH-DATA|");
1526 				l_ptr->stats.bearer_congs++;
1527 				return PUSH_FAILED;
1528 			}
1529 		}
1530 	}
1531 	return PUSH_FINISHED;
1532 }
1533 
1534 /*
1535  * push_queue(): push out the unsent messages of a link where
1536  *               congestion has abated. Node is locked
1537  */
1538 void tipc_link_push_queue(struct link *l_ptr)
1539 {
1540 	u32 res;
1541 
1542 	if (tipc_bearer_congested(l_ptr->b_ptr, l_ptr))
1543 		return;
1544 
1545 	do {
1546 		res = tipc_link_push_packet(l_ptr);
1547 	} while (!res);
1548 
1549 	if (res == PUSH_FAILED)
1550 		tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
1551 }
1552 
1553 static void link_reset_all(unsigned long addr)
1554 {
1555 	struct tipc_node *n_ptr;
1556 	char addr_string[16];
1557 	u32 i;
1558 
1559 	read_lock_bh(&tipc_net_lock);
1560 	n_ptr = tipc_node_find((u32)addr);
1561 	if (!n_ptr) {
1562 		read_unlock_bh(&tipc_net_lock);
1563 		return;	/* node no longer exists */
1564 	}
1565 
1566 	tipc_node_lock(n_ptr);
1567 
1568 	warn("Resetting all links to %s\n",
1569 	     tipc_addr_string_fill(addr_string, n_ptr->addr));
1570 
1571 	for (i = 0; i < MAX_BEARERS; i++) {
1572 		if (n_ptr->links[i]) {
1573 			link_print(n_ptr->links[i], TIPC_OUTPUT,
1574 				   "Resetting link\n");
1575 			tipc_link_reset(n_ptr->links[i]);
1576 		}
1577 	}
1578 
1579 	tipc_node_unlock(n_ptr);
1580 	read_unlock_bh(&tipc_net_lock);
1581 }
1582 
1583 static void link_retransmit_failure(struct link *l_ptr, struct sk_buff *buf)
1584 {
1585 	struct tipc_msg *msg = buf_msg(buf);
1586 
1587 	warn("Retransmission failure on link <%s>\n", l_ptr->name);
1588 	tipc_msg_dbg(TIPC_OUTPUT, msg, ">RETR-FAIL>");
1589 
1590 	if (l_ptr->addr) {
1591 
1592 		/* Handle failure on standard link */
1593 
1594 		link_print(l_ptr, TIPC_OUTPUT, "Resetting link\n");
1595 		tipc_link_reset(l_ptr);
1596 
1597 	} else {
1598 
1599 		/* Handle failure on broadcast link */
1600 
1601 		struct tipc_node *n_ptr;
1602 		char addr_string[16];
1603 
1604 		tipc_printf(TIPC_OUTPUT, "Msg seq number: %u,  ", msg_seqno(msg));
1605 		tipc_printf(TIPC_OUTPUT, "Outstanding acks: %lu\n",
1606 				     (unsigned long) TIPC_SKB_CB(buf)->handle);
1607 
1608 		n_ptr = l_ptr->owner->next;
1609 		tipc_node_lock(n_ptr);
1610 
1611 		tipc_addr_string_fill(addr_string, n_ptr->addr);
1612 		tipc_printf(TIPC_OUTPUT, "Multicast link info for %s\n", addr_string);
1613 		tipc_printf(TIPC_OUTPUT, "Supported: %d,  ", n_ptr->bclink.supported);
1614 		tipc_printf(TIPC_OUTPUT, "Acked: %u\n", n_ptr->bclink.acked);
1615 		tipc_printf(TIPC_OUTPUT, "Last in: %u,  ", n_ptr->bclink.last_in);
1616 		tipc_printf(TIPC_OUTPUT, "Gap after: %u,  ", n_ptr->bclink.gap_after);
1617 		tipc_printf(TIPC_OUTPUT, "Gap to: %u\n", n_ptr->bclink.gap_to);
1618 		tipc_printf(TIPC_OUTPUT, "Nack sync: %u\n\n", n_ptr->bclink.nack_sync);
1619 
1620 		tipc_k_signal((Handler)link_reset_all, (unsigned long)n_ptr->addr);
1621 
1622 		tipc_node_unlock(n_ptr);
1623 
1624 		l_ptr->stale_count = 0;
1625 	}
1626 }
1627 
1628 void tipc_link_retransmit(struct link *l_ptr, struct sk_buff *buf,
1629 			  u32 retransmits)
1630 {
1631 	struct tipc_msg *msg;
1632 
1633 	if (!buf)
1634 		return;
1635 
1636 	msg = buf_msg(buf);
1637 
1638 	dbg("Retransmitting %u in link %x\n", retransmits, l_ptr);
1639 
1640 	if (tipc_bearer_congested(l_ptr->b_ptr, l_ptr)) {
1641 		if (l_ptr->retransm_queue_size == 0) {
1642 			msg_dbg(msg, ">NO_RETR->BCONG>");
1643 			dbg_print_link(l_ptr, "   ");
1644 			l_ptr->retransm_queue_head = msg_seqno(msg);
1645 			l_ptr->retransm_queue_size = retransmits;
1646 		} else {
1647 			err("Unexpected retransmit on link %s (qsize=%d)\n",
1648 			    l_ptr->name, l_ptr->retransm_queue_size);
1649 		}
1650 		return;
1651 	} else {
1652 		/* Detect repeated retransmit failures on uncongested bearer */
1653 
1654 		if (l_ptr->last_retransmitted == msg_seqno(msg)) {
1655 			if (++l_ptr->stale_count > 100) {
1656 				link_retransmit_failure(l_ptr, buf);
1657 				return;
1658 			}
1659 		} else {
1660 			l_ptr->last_retransmitted = msg_seqno(msg);
1661 			l_ptr->stale_count = 1;
1662 		}
1663 	}
1664 
1665 	while (retransmits && (buf != l_ptr->next_out) && buf) {
1666 		msg = buf_msg(buf);
1667 		msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1668 		msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1669 		if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1670 			msg_dbg(buf_msg(buf), ">RETR>");
1671 			buf = buf->next;
1672 			retransmits--;
1673 			l_ptr->stats.retransmitted++;
1674 		} else {
1675 			tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
1676 			l_ptr->stats.bearer_congs++;
1677 			l_ptr->retransm_queue_head = msg_seqno(buf_msg(buf));
1678 			l_ptr->retransm_queue_size = retransmits;
1679 			return;
1680 		}
1681 	}
1682 
1683 	l_ptr->retransm_queue_head = l_ptr->retransm_queue_size = 0;
1684 }
1685 
1686 /**
1687  * link_insert_deferred_queue - insert deferred messages back into receive chain
1688  */
1689 
1690 static struct sk_buff *link_insert_deferred_queue(struct link *l_ptr,
1691 						  struct sk_buff *buf)
1692 {
1693 	u32 seq_no;
1694 
1695 	if (l_ptr->oldest_deferred_in == NULL)
1696 		return buf;
1697 
1698 	seq_no = msg_seqno(buf_msg(l_ptr->oldest_deferred_in));
1699 	if (seq_no == mod(l_ptr->next_in_no)) {
1700 		l_ptr->newest_deferred_in->next = buf;
1701 		buf = l_ptr->oldest_deferred_in;
1702 		l_ptr->oldest_deferred_in = NULL;
1703 		l_ptr->deferred_inqueue_sz = 0;
1704 	}
1705 	return buf;
1706 }
1707 
1708 /**
1709  * link_recv_buf_validate - validate basic format of received message
1710  *
1711  * This routine ensures a TIPC message has an acceptable header, and at least
1712  * as much data as the header indicates it should.  The routine also ensures
1713  * that the entire message header is stored in the main fragment of the message
1714  * buffer, to simplify future access to message header fields.
1715  *
1716  * Note: Having extra info present in the message header or data areas is OK.
1717  * TIPC will ignore the excess, under the assumption that it is optional info
1718  * introduced by a later release of the protocol.
1719  */
1720 
1721 static int link_recv_buf_validate(struct sk_buff *buf)
1722 {
1723 	static u32 min_data_hdr_size[8] = {
1724 		SHORT_H_SIZE, MCAST_H_SIZE, LONG_H_SIZE, DIR_MSG_H_SIZE,
1725 		MAX_H_SIZE, MAX_H_SIZE, MAX_H_SIZE, MAX_H_SIZE
1726 		};
1727 
1728 	struct tipc_msg *msg;
1729 	u32 tipc_hdr[2];
1730 	u32 size;
1731 	u32 hdr_size;
1732 	u32 min_hdr_size;
1733 
1734 	if (unlikely(buf->len < MIN_H_SIZE))
1735 		return 0;
1736 
1737 	msg = skb_header_pointer(buf, 0, sizeof(tipc_hdr), tipc_hdr);
1738 	if (msg == NULL)
1739 		return 0;
1740 
1741 	if (unlikely(msg_version(msg) != TIPC_VERSION))
1742 		return 0;
1743 
1744 	size = msg_size(msg);
1745 	hdr_size = msg_hdr_sz(msg);
1746 	min_hdr_size = msg_isdata(msg) ?
1747 		min_data_hdr_size[msg_type(msg)] : INT_H_SIZE;
1748 
1749 	if (unlikely((hdr_size < min_hdr_size) ||
1750 		     (size < hdr_size) ||
1751 		     (buf->len < size) ||
1752 		     (size - hdr_size > TIPC_MAX_USER_MSG_SIZE)))
1753 		return 0;
1754 
1755 	return pskb_may_pull(buf, hdr_size);
1756 }
1757 
1758 /**
1759  * tipc_recv_msg - process TIPC messages arriving from off-node
1760  * @head: pointer to message buffer chain
1761  * @tb_ptr: pointer to bearer message arrived on
1762  *
1763  * Invoked with no locks held.  Bearer pointer must point to a valid bearer
1764  * structure (i.e. cannot be NULL), but bearer can be inactive.
1765  */
1766 
1767 void tipc_recv_msg(struct sk_buff *head, struct tipc_bearer *tb_ptr)
1768 {
1769 	read_lock_bh(&tipc_net_lock);
1770 	while (head) {
1771 		struct bearer *b_ptr = (struct bearer *)tb_ptr;
1772 		struct tipc_node *n_ptr;
1773 		struct link *l_ptr;
1774 		struct sk_buff *crs;
1775 		struct sk_buff *buf = head;
1776 		struct tipc_msg *msg;
1777 		u32 seq_no;
1778 		u32 ackd;
1779 		u32 released = 0;
1780 		int type;
1781 
1782 		head = head->next;
1783 
1784 		/* Ensure bearer is still enabled */
1785 
1786 		if (unlikely(!b_ptr->active))
1787 			goto cont;
1788 
1789 		/* Ensure message is well-formed */
1790 
1791 		if (unlikely(!link_recv_buf_validate(buf)))
1792 			goto cont;
1793 
1794 		/* Ensure message data is a single contiguous unit */
1795 
1796 		if (unlikely(buf_linearize(buf))) {
1797 			goto cont;
1798 		}
1799 
1800 		/* Handle arrival of a non-unicast link message */
1801 
1802 		msg = buf_msg(buf);
1803 
1804 		if (unlikely(msg_non_seq(msg))) {
1805 			if (msg_user(msg) ==  LINK_CONFIG)
1806 				tipc_disc_recv_msg(buf, b_ptr);
1807 			else
1808 				tipc_bclink_recv_pkt(buf);
1809 			continue;
1810 		}
1811 
1812 		if (unlikely(!msg_short(msg) &&
1813 			     (msg_destnode(msg) != tipc_own_addr)))
1814 			goto cont;
1815 
1816 		/* Discard non-routeable messages destined for another node */
1817 
1818 		if (unlikely(!msg_isdata(msg) &&
1819 			     (msg_destnode(msg) != tipc_own_addr))) {
1820 			if ((msg_user(msg) != CONN_MANAGER) &&
1821 			    (msg_user(msg) != MSG_FRAGMENTER))
1822 				goto cont;
1823 		}
1824 
1825 		/* Locate neighboring node that sent message */
1826 
1827 		n_ptr = tipc_node_find(msg_prevnode(msg));
1828 		if (unlikely(!n_ptr))
1829 			goto cont;
1830 		tipc_node_lock(n_ptr);
1831 
1832 		/* Don't talk to neighbor during cleanup after last session */
1833 
1834 		if (n_ptr->cleanup_required) {
1835 			tipc_node_unlock(n_ptr);
1836 			goto cont;
1837 		}
1838 
1839 		/* Locate unicast link endpoint that should handle message */
1840 
1841 		l_ptr = n_ptr->links[b_ptr->identity];
1842 		if (unlikely(!l_ptr)) {
1843 			tipc_node_unlock(n_ptr);
1844 			goto cont;
1845 		}
1846 
1847 		/* Validate message sequence number info */
1848 
1849 		seq_no = msg_seqno(msg);
1850 		ackd = msg_ack(msg);
1851 
1852 		/* Release acked messages */
1853 
1854 		if (less(n_ptr->bclink.acked, msg_bcast_ack(msg))) {
1855 			if (tipc_node_is_up(n_ptr) && n_ptr->bclink.supported)
1856 				tipc_bclink_acknowledge(n_ptr, msg_bcast_ack(msg));
1857 		}
1858 
1859 		crs = l_ptr->first_out;
1860 		while ((crs != l_ptr->next_out) &&
1861 		       less_eq(msg_seqno(buf_msg(crs)), ackd)) {
1862 			struct sk_buff *next = crs->next;
1863 
1864 			buf_discard(crs);
1865 			crs = next;
1866 			released++;
1867 		}
1868 		if (released) {
1869 			l_ptr->first_out = crs;
1870 			l_ptr->out_queue_size -= released;
1871 		}
1872 
1873 		/* Try sending any messages link endpoint has pending */
1874 
1875 		if (unlikely(l_ptr->next_out))
1876 			tipc_link_push_queue(l_ptr);
1877 		if (unlikely(!list_empty(&l_ptr->waiting_ports)))
1878 			tipc_link_wakeup_ports(l_ptr, 0);
1879 		if (unlikely(++l_ptr->unacked_window >= TIPC_MIN_LINK_WIN)) {
1880 			l_ptr->stats.sent_acks++;
1881 			tipc_link_send_proto_msg(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
1882 		}
1883 
1884 		/* Now (finally!) process the incoming message */
1885 
1886 protocol_check:
1887 		if (likely(link_working_working(l_ptr))) {
1888 			if (likely(seq_no == mod(l_ptr->next_in_no))) {
1889 				l_ptr->next_in_no++;
1890 				if (unlikely(l_ptr->oldest_deferred_in))
1891 					head = link_insert_deferred_queue(l_ptr,
1892 									  head);
1893 				if (likely(msg_is_dest(msg, tipc_own_addr))) {
1894 deliver:
1895 					if (likely(msg_isdata(msg))) {
1896 						tipc_node_unlock(n_ptr);
1897 						tipc_port_recv_msg(buf);
1898 						continue;
1899 					}
1900 					switch (msg_user(msg)) {
1901 					case MSG_BUNDLER:
1902 						l_ptr->stats.recv_bundles++;
1903 						l_ptr->stats.recv_bundled +=
1904 							msg_msgcnt(msg);
1905 						tipc_node_unlock(n_ptr);
1906 						tipc_link_recv_bundle(buf);
1907 						continue;
1908 					case ROUTE_DISTRIBUTOR:
1909 						tipc_node_unlock(n_ptr);
1910 						tipc_cltr_recv_routing_table(buf);
1911 						continue;
1912 					case NAME_DISTRIBUTOR:
1913 						tipc_node_unlock(n_ptr);
1914 						tipc_named_recv(buf);
1915 						continue;
1916 					case CONN_MANAGER:
1917 						tipc_node_unlock(n_ptr);
1918 						tipc_port_recv_proto_msg(buf);
1919 						continue;
1920 					case MSG_FRAGMENTER:
1921 						l_ptr->stats.recv_fragments++;
1922 						if (tipc_link_recv_fragment(&l_ptr->defragm_buf,
1923 									    &buf, &msg)) {
1924 							l_ptr->stats.recv_fragmented++;
1925 							goto deliver;
1926 						}
1927 						break;
1928 					case CHANGEOVER_PROTOCOL:
1929 						type = msg_type(msg);
1930 						if (link_recv_changeover_msg(&l_ptr, &buf)) {
1931 							msg = buf_msg(buf);
1932 							seq_no = msg_seqno(msg);
1933 							if (type == ORIGINAL_MSG)
1934 								goto deliver;
1935 							goto protocol_check;
1936 						}
1937 						break;
1938 					}
1939 				}
1940 				tipc_node_unlock(n_ptr);
1941 				tipc_net_route_msg(buf);
1942 				continue;
1943 			}
1944 			link_handle_out_of_seq_msg(l_ptr, buf);
1945 			head = link_insert_deferred_queue(l_ptr, head);
1946 			tipc_node_unlock(n_ptr);
1947 			continue;
1948 		}
1949 
1950 		if (msg_user(msg) == LINK_PROTOCOL) {
1951 			link_recv_proto_msg(l_ptr, buf);
1952 			head = link_insert_deferred_queue(l_ptr, head);
1953 			tipc_node_unlock(n_ptr);
1954 			continue;
1955 		}
1956 		msg_dbg(msg,"NSEQ<REC<");
1957 		link_state_event(l_ptr, TRAFFIC_MSG_EVT);
1958 
1959 		if (link_working_working(l_ptr)) {
1960 			/* Re-insert in front of queue */
1961 			msg_dbg(msg,"RECV-REINS:");
1962 			buf->next = head;
1963 			head = buf;
1964 			tipc_node_unlock(n_ptr);
1965 			continue;
1966 		}
1967 		tipc_node_unlock(n_ptr);
1968 cont:
1969 		buf_discard(buf);
1970 	}
1971 	read_unlock_bh(&tipc_net_lock);
1972 }
1973 
1974 /*
1975  * link_defer_buf(): Sort a received out-of-sequence packet
1976  *                   into the deferred reception queue.
1977  * Returns the increase of the queue length,i.e. 0 or 1
1978  */
1979 
1980 u32 tipc_link_defer_pkt(struct sk_buff **head,
1981 			struct sk_buff **tail,
1982 			struct sk_buff *buf)
1983 {
1984 	struct sk_buff *prev = NULL;
1985 	struct sk_buff *crs = *head;
1986 	u32 seq_no = msg_seqno(buf_msg(buf));
1987 
1988 	buf->next = NULL;
1989 
1990 	/* Empty queue ? */
1991 	if (*head == NULL) {
1992 		*head = *tail = buf;
1993 		return 1;
1994 	}
1995 
1996 	/* Last ? */
1997 	if (less(msg_seqno(buf_msg(*tail)), seq_no)) {
1998 		(*tail)->next = buf;
1999 		*tail = buf;
2000 		return 1;
2001 	}
2002 
2003 	/* Scan through queue and sort it in */
2004 	do {
2005 		struct tipc_msg *msg = buf_msg(crs);
2006 
2007 		if (less(seq_no, msg_seqno(msg))) {
2008 			buf->next = crs;
2009 			if (prev)
2010 				prev->next = buf;
2011 			else
2012 				*head = buf;
2013 			return 1;
2014 		}
2015 		if (seq_no == msg_seqno(msg)) {
2016 			break;
2017 		}
2018 		prev = crs;
2019 		crs = crs->next;
2020 	}
2021 	while (crs);
2022 
2023 	/* Message is a duplicate of an existing message */
2024 
2025 	buf_discard(buf);
2026 	return 0;
2027 }
2028 
2029 /**
2030  * link_handle_out_of_seq_msg - handle arrival of out-of-sequence packet
2031  */
2032 
2033 static void link_handle_out_of_seq_msg(struct link *l_ptr,
2034 				       struct sk_buff *buf)
2035 {
2036 	u32 seq_no = msg_seqno(buf_msg(buf));
2037 
2038 	if (likely(msg_user(buf_msg(buf)) == LINK_PROTOCOL)) {
2039 		link_recv_proto_msg(l_ptr, buf);
2040 		return;
2041 	}
2042 
2043 	dbg("rx OOS msg: seq_no %u, expecting %u (%u)\n",
2044 	    seq_no, mod(l_ptr->next_in_no), l_ptr->next_in_no);
2045 
2046 	/* Record OOS packet arrival (force mismatch on next timeout) */
2047 
2048 	l_ptr->checkpoint--;
2049 
2050 	/*
2051 	 * Discard packet if a duplicate; otherwise add it to deferred queue
2052 	 * and notify peer of gap as per protocol specification
2053 	 */
2054 
2055 	if (less(seq_no, mod(l_ptr->next_in_no))) {
2056 		l_ptr->stats.duplicates++;
2057 		buf_discard(buf);
2058 		return;
2059 	}
2060 
2061 	if (tipc_link_defer_pkt(&l_ptr->oldest_deferred_in,
2062 				&l_ptr->newest_deferred_in, buf)) {
2063 		l_ptr->deferred_inqueue_sz++;
2064 		l_ptr->stats.deferred_recv++;
2065 		if ((l_ptr->deferred_inqueue_sz % 16) == 1)
2066 			tipc_link_send_proto_msg(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
2067 	} else
2068 		l_ptr->stats.duplicates++;
2069 }
2070 
2071 /*
2072  * Send protocol message to the other endpoint.
2073  */
2074 void tipc_link_send_proto_msg(struct link *l_ptr, u32 msg_typ, int probe_msg,
2075 			      u32 gap, u32 tolerance, u32 priority, u32 ack_mtu)
2076 {
2077 	struct sk_buff *buf = NULL;
2078 	struct tipc_msg *msg = l_ptr->pmsg;
2079 	u32 msg_size = sizeof(l_ptr->proto_msg);
2080 
2081 	if (link_blocked(l_ptr))
2082 		return;
2083 	msg_set_type(msg, msg_typ);
2084 	msg_set_net_plane(msg, l_ptr->b_ptr->net_plane);
2085 	msg_set_bcast_ack(msg, mod(l_ptr->owner->bclink.last_in));
2086 	msg_set_last_bcast(msg, tipc_bclink_get_last_sent());
2087 
2088 	if (msg_typ == STATE_MSG) {
2089 		u32 next_sent = mod(l_ptr->next_out_no);
2090 
2091 		if (!tipc_link_is_up(l_ptr))
2092 			return;
2093 		if (l_ptr->next_out)
2094 			next_sent = msg_seqno(buf_msg(l_ptr->next_out));
2095 		msg_set_next_sent(msg, next_sent);
2096 		if (l_ptr->oldest_deferred_in) {
2097 			u32 rec = msg_seqno(buf_msg(l_ptr->oldest_deferred_in));
2098 			gap = mod(rec - mod(l_ptr->next_in_no));
2099 		}
2100 		msg_set_seq_gap(msg, gap);
2101 		if (gap)
2102 			l_ptr->stats.sent_nacks++;
2103 		msg_set_link_tolerance(msg, tolerance);
2104 		msg_set_linkprio(msg, priority);
2105 		msg_set_max_pkt(msg, ack_mtu);
2106 		msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
2107 		msg_set_probe(msg, probe_msg != 0);
2108 		if (probe_msg) {
2109 			u32 mtu = l_ptr->max_pkt;
2110 
2111 			if ((mtu < l_ptr->max_pkt_target) &&
2112 			    link_working_working(l_ptr) &&
2113 			    l_ptr->fsm_msg_cnt) {
2114 				msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
2115 				if (l_ptr->max_pkt_probes == 10) {
2116 					l_ptr->max_pkt_target = (msg_size - 4);
2117 					l_ptr->max_pkt_probes = 0;
2118 					msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
2119 				}
2120 				l_ptr->max_pkt_probes++;
2121 			}
2122 
2123 			l_ptr->stats.sent_probes++;
2124 		}
2125 		l_ptr->stats.sent_states++;
2126 	} else {		/* RESET_MSG or ACTIVATE_MSG */
2127 		msg_set_ack(msg, mod(l_ptr->reset_checkpoint - 1));
2128 		msg_set_seq_gap(msg, 0);
2129 		msg_set_next_sent(msg, 1);
2130 		msg_set_link_tolerance(msg, l_ptr->tolerance);
2131 		msg_set_linkprio(msg, l_ptr->priority);
2132 		msg_set_max_pkt(msg, l_ptr->max_pkt_target);
2133 	}
2134 
2135 	if (tipc_node_has_redundant_links(l_ptr->owner)) {
2136 		msg_set_redundant_link(msg);
2137 	} else {
2138 		msg_clear_redundant_link(msg);
2139 	}
2140 	msg_set_linkprio(msg, l_ptr->priority);
2141 
2142 	/* Ensure sequence number will not fit : */
2143 
2144 	msg_set_seqno(msg, mod(l_ptr->next_out_no + (0xffff/2)));
2145 
2146 	/* Congestion? */
2147 
2148 	if (tipc_bearer_congested(l_ptr->b_ptr, l_ptr)) {
2149 		if (!l_ptr->proto_msg_queue) {
2150 			l_ptr->proto_msg_queue =
2151 				tipc_buf_acquire(sizeof(l_ptr->proto_msg));
2152 		}
2153 		buf = l_ptr->proto_msg_queue;
2154 		if (!buf)
2155 			return;
2156 		skb_copy_to_linear_data(buf, msg, sizeof(l_ptr->proto_msg));
2157 		return;
2158 	}
2159 	msg_set_timestamp(msg, jiffies_to_msecs(jiffies));
2160 
2161 	/* Message can be sent */
2162 
2163 	msg_dbg(msg, ">>");
2164 
2165 	buf = tipc_buf_acquire(msg_size);
2166 	if (!buf)
2167 		return;
2168 
2169 	skb_copy_to_linear_data(buf, msg, sizeof(l_ptr->proto_msg));
2170 	msg_set_size(buf_msg(buf), msg_size);
2171 
2172 	if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
2173 		l_ptr->unacked_window = 0;
2174 		buf_discard(buf);
2175 		return;
2176 	}
2177 
2178 	/* New congestion */
2179 	tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
2180 	l_ptr->proto_msg_queue = buf;
2181 	l_ptr->stats.bearer_congs++;
2182 }
2183 
2184 /*
2185  * Receive protocol message :
2186  * Note that network plane id propagates through the network, and may
2187  * change at any time. The node with lowest address rules
2188  */
2189 
2190 static void link_recv_proto_msg(struct link *l_ptr, struct sk_buff *buf)
2191 {
2192 	u32 rec_gap = 0;
2193 	u32 max_pkt_info;
2194 	u32 max_pkt_ack;
2195 	u32 msg_tol;
2196 	struct tipc_msg *msg = buf_msg(buf);
2197 
2198 	dbg("AT(%u):", jiffies_to_msecs(jiffies));
2199 	msg_dbg(msg, "<<");
2200 	if (link_blocked(l_ptr))
2201 		goto exit;
2202 
2203 	/* record unnumbered packet arrival (force mismatch on next timeout) */
2204 
2205 	l_ptr->checkpoint--;
2206 
2207 	if (l_ptr->b_ptr->net_plane != msg_net_plane(msg))
2208 		if (tipc_own_addr > msg_prevnode(msg))
2209 			l_ptr->b_ptr->net_plane = msg_net_plane(msg);
2210 
2211 	l_ptr->owner->permit_changeover = msg_redundant_link(msg);
2212 
2213 	switch (msg_type(msg)) {
2214 
2215 	case RESET_MSG:
2216 		if (!link_working_unknown(l_ptr) &&
2217 		    (l_ptr->peer_session != INVALID_SESSION)) {
2218 			if (msg_session(msg) == l_ptr->peer_session) {
2219 				dbg("Duplicate RESET: %u<->%u\n",
2220 				    msg_session(msg), l_ptr->peer_session);
2221 				break; /* duplicate: ignore */
2222 			}
2223 		}
2224 		/* fall thru' */
2225 	case ACTIVATE_MSG:
2226 		/* Update link settings according other endpoint's values */
2227 
2228 		strcpy((strrchr(l_ptr->name, ':') + 1), (char *)msg_data(msg));
2229 
2230 		if ((msg_tol = msg_link_tolerance(msg)) &&
2231 		    (msg_tol > l_ptr->tolerance))
2232 			link_set_supervision_props(l_ptr, msg_tol);
2233 
2234 		if (msg_linkprio(msg) > l_ptr->priority)
2235 			l_ptr->priority = msg_linkprio(msg);
2236 
2237 		max_pkt_info = msg_max_pkt(msg);
2238 		if (max_pkt_info) {
2239 			if (max_pkt_info < l_ptr->max_pkt_target)
2240 				l_ptr->max_pkt_target = max_pkt_info;
2241 			if (l_ptr->max_pkt > l_ptr->max_pkt_target)
2242 				l_ptr->max_pkt = l_ptr->max_pkt_target;
2243 		} else {
2244 			l_ptr->max_pkt = l_ptr->max_pkt_target;
2245 		}
2246 		l_ptr->owner->bclink.supported = (max_pkt_info != 0);
2247 
2248 		link_state_event(l_ptr, msg_type(msg));
2249 
2250 		l_ptr->peer_session = msg_session(msg);
2251 		l_ptr->peer_bearer_id = msg_bearer_id(msg);
2252 
2253 		/* Synchronize broadcast sequence numbers */
2254 		if (!tipc_node_has_redundant_links(l_ptr->owner)) {
2255 			l_ptr->owner->bclink.last_in = mod(msg_last_bcast(msg));
2256 		}
2257 		break;
2258 	case STATE_MSG:
2259 
2260 		if ((msg_tol = msg_link_tolerance(msg)))
2261 			link_set_supervision_props(l_ptr, msg_tol);
2262 
2263 		if (msg_linkprio(msg) &&
2264 		    (msg_linkprio(msg) != l_ptr->priority)) {
2265 			warn("Resetting link <%s>, priority change %u->%u\n",
2266 			     l_ptr->name, l_ptr->priority, msg_linkprio(msg));
2267 			l_ptr->priority = msg_linkprio(msg);
2268 			tipc_link_reset(l_ptr); /* Enforce change to take effect */
2269 			break;
2270 		}
2271 		link_state_event(l_ptr, TRAFFIC_MSG_EVT);
2272 		l_ptr->stats.recv_states++;
2273 		if (link_reset_unknown(l_ptr))
2274 			break;
2275 
2276 		if (less_eq(mod(l_ptr->next_in_no), msg_next_sent(msg))) {
2277 			rec_gap = mod(msg_next_sent(msg) -
2278 				      mod(l_ptr->next_in_no));
2279 		}
2280 
2281 		max_pkt_ack = msg_max_pkt(msg);
2282 		if (max_pkt_ack > l_ptr->max_pkt) {
2283 			dbg("Link <%s> updated MTU %u -> %u\n",
2284 			    l_ptr->name, l_ptr->max_pkt, max_pkt_ack);
2285 			l_ptr->max_pkt = max_pkt_ack;
2286 			l_ptr->max_pkt_probes = 0;
2287 		}
2288 
2289 		max_pkt_ack = 0;
2290 		if (msg_probe(msg)) {
2291 			l_ptr->stats.recv_probes++;
2292 			if (msg_size(msg) > sizeof(l_ptr->proto_msg)) {
2293 				max_pkt_ack = msg_size(msg);
2294 			}
2295 		}
2296 
2297 		/* Protocol message before retransmits, reduce loss risk */
2298 
2299 		tipc_bclink_check_gap(l_ptr->owner, msg_last_bcast(msg));
2300 
2301 		if (rec_gap || (msg_probe(msg))) {
2302 			tipc_link_send_proto_msg(l_ptr, STATE_MSG,
2303 						 0, rec_gap, 0, 0, max_pkt_ack);
2304 		}
2305 		if (msg_seq_gap(msg)) {
2306 			msg_dbg(msg, "With Gap:");
2307 			l_ptr->stats.recv_nacks++;
2308 			tipc_link_retransmit(l_ptr, l_ptr->first_out,
2309 					     msg_seq_gap(msg));
2310 		}
2311 		break;
2312 	default:
2313 		msg_dbg(buf_msg(buf), "<DISCARDING UNKNOWN<");
2314 	}
2315 exit:
2316 	buf_discard(buf);
2317 }
2318 
2319 
2320 /*
2321  * tipc_link_tunnel(): Send one message via a link belonging to
2322  * another bearer. Owner node is locked.
2323  */
2324 static void tipc_link_tunnel(struct link *l_ptr,
2325 			     struct tipc_msg *tunnel_hdr,
2326 			     struct tipc_msg  *msg,
2327 			     u32 selector)
2328 {
2329 	struct link *tunnel;
2330 	struct sk_buff *buf;
2331 	u32 length = msg_size(msg);
2332 
2333 	tunnel = l_ptr->owner->active_links[selector & 1];
2334 	if (!tipc_link_is_up(tunnel)) {
2335 		warn("Link changeover error, "
2336 		     "tunnel link no longer available\n");
2337 		return;
2338 	}
2339 	msg_set_size(tunnel_hdr, length + INT_H_SIZE);
2340 	buf = tipc_buf_acquire(length + INT_H_SIZE);
2341 	if (!buf) {
2342 		warn("Link changeover error, "
2343 		     "unable to send tunnel msg\n");
2344 		return;
2345 	}
2346 	skb_copy_to_linear_data(buf, tunnel_hdr, INT_H_SIZE);
2347 	skb_copy_to_linear_data_offset(buf, INT_H_SIZE, msg, length);
2348 	dbg("%c->%c:", l_ptr->b_ptr->net_plane, tunnel->b_ptr->net_plane);
2349 	msg_dbg(buf_msg(buf), ">SEND>");
2350 	tipc_link_send_buf(tunnel, buf);
2351 }
2352 
2353 
2354 
2355 /*
2356  * changeover(): Send whole message queue via the remaining link
2357  *               Owner node is locked.
2358  */
2359 
2360 void tipc_link_changeover(struct link *l_ptr)
2361 {
2362 	u32 msgcount = l_ptr->out_queue_size;
2363 	struct sk_buff *crs = l_ptr->first_out;
2364 	struct link *tunnel = l_ptr->owner->active_links[0];
2365 	struct tipc_msg tunnel_hdr;
2366 	int split_bundles;
2367 
2368 	if (!tunnel)
2369 		return;
2370 
2371 	if (!l_ptr->owner->permit_changeover) {
2372 		warn("Link changeover error, "
2373 		     "peer did not permit changeover\n");
2374 		return;
2375 	}
2376 
2377 	tipc_msg_init(&tunnel_hdr, CHANGEOVER_PROTOCOL,
2378 		 ORIGINAL_MSG, INT_H_SIZE, l_ptr->addr);
2379 	msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
2380 	msg_set_msgcnt(&tunnel_hdr, msgcount);
2381 	dbg("Link changeover requires %u tunnel messages\n", msgcount);
2382 
2383 	if (!l_ptr->first_out) {
2384 		struct sk_buff *buf;
2385 
2386 		buf = tipc_buf_acquire(INT_H_SIZE);
2387 		if (buf) {
2388 			skb_copy_to_linear_data(buf, &tunnel_hdr, INT_H_SIZE);
2389 			msg_set_size(&tunnel_hdr, INT_H_SIZE);
2390 			dbg("%c->%c:", l_ptr->b_ptr->net_plane,
2391 			    tunnel->b_ptr->net_plane);
2392 			msg_dbg(&tunnel_hdr, "EMPTY>SEND>");
2393 			tipc_link_send_buf(tunnel, buf);
2394 		} else {
2395 			warn("Link changeover error, "
2396 			     "unable to send changeover msg\n");
2397 		}
2398 		return;
2399 	}
2400 
2401 	split_bundles = (l_ptr->owner->active_links[0] !=
2402 			 l_ptr->owner->active_links[1]);
2403 
2404 	while (crs) {
2405 		struct tipc_msg *msg = buf_msg(crs);
2406 
2407 		if ((msg_user(msg) == MSG_BUNDLER) && split_bundles) {
2408 			struct tipc_msg *m = msg_get_wrapped(msg);
2409 			unchar* pos = (unchar*)m;
2410 
2411 			msgcount = msg_msgcnt(msg);
2412 			while (msgcount--) {
2413 				msg_set_seqno(m,msg_seqno(msg));
2414 				tipc_link_tunnel(l_ptr, &tunnel_hdr, m,
2415 						 msg_link_selector(m));
2416 				pos += align(msg_size(m));
2417 				m = (struct tipc_msg *)pos;
2418 			}
2419 		} else {
2420 			tipc_link_tunnel(l_ptr, &tunnel_hdr, msg,
2421 					 msg_link_selector(msg));
2422 		}
2423 		crs = crs->next;
2424 	}
2425 }
2426 
2427 void tipc_link_send_duplicate(struct link *l_ptr, struct link *tunnel)
2428 {
2429 	struct sk_buff *iter;
2430 	struct tipc_msg tunnel_hdr;
2431 
2432 	tipc_msg_init(&tunnel_hdr, CHANGEOVER_PROTOCOL,
2433 		 DUPLICATE_MSG, INT_H_SIZE, l_ptr->addr);
2434 	msg_set_msgcnt(&tunnel_hdr, l_ptr->out_queue_size);
2435 	msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
2436 	iter = l_ptr->first_out;
2437 	while (iter) {
2438 		struct sk_buff *outbuf;
2439 		struct tipc_msg *msg = buf_msg(iter);
2440 		u32 length = msg_size(msg);
2441 
2442 		if (msg_user(msg) == MSG_BUNDLER)
2443 			msg_set_type(msg, CLOSED_MSG);
2444 		msg_set_ack(msg, mod(l_ptr->next_in_no - 1));	/* Update */
2445 		msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
2446 		msg_set_size(&tunnel_hdr, length + INT_H_SIZE);
2447 		outbuf = tipc_buf_acquire(length + INT_H_SIZE);
2448 		if (outbuf == NULL) {
2449 			warn("Link changeover error, "
2450 			     "unable to send duplicate msg\n");
2451 			return;
2452 		}
2453 		skb_copy_to_linear_data(outbuf, &tunnel_hdr, INT_H_SIZE);
2454 		skb_copy_to_linear_data_offset(outbuf, INT_H_SIZE, iter->data,
2455 					       length);
2456 		dbg("%c->%c:", l_ptr->b_ptr->net_plane,
2457 		    tunnel->b_ptr->net_plane);
2458 		msg_dbg(buf_msg(outbuf), ">SEND>");
2459 		tipc_link_send_buf(tunnel, outbuf);
2460 		if (!tipc_link_is_up(l_ptr))
2461 			return;
2462 		iter = iter->next;
2463 	}
2464 }
2465 
2466 
2467 
2468 /**
2469  * buf_extract - extracts embedded TIPC message from another message
2470  * @skb: encapsulating message buffer
2471  * @from_pos: offset to extract from
2472  *
2473  * Returns a new message buffer containing an embedded message.  The
2474  * encapsulating message itself is left unchanged.
2475  */
2476 
2477 static struct sk_buff *buf_extract(struct sk_buff *skb, u32 from_pos)
2478 {
2479 	struct tipc_msg *msg = (struct tipc_msg *)(skb->data + from_pos);
2480 	u32 size = msg_size(msg);
2481 	struct sk_buff *eb;
2482 
2483 	eb = tipc_buf_acquire(size);
2484 	if (eb)
2485 		skb_copy_to_linear_data(eb, msg, size);
2486 	return eb;
2487 }
2488 
2489 /*
2490  *  link_recv_changeover_msg(): Receive tunneled packet sent
2491  *  via other link. Node is locked. Return extracted buffer.
2492  */
2493 
2494 static int link_recv_changeover_msg(struct link **l_ptr,
2495 				    struct sk_buff **buf)
2496 {
2497 	struct sk_buff *tunnel_buf = *buf;
2498 	struct link *dest_link;
2499 	struct tipc_msg *msg;
2500 	struct tipc_msg *tunnel_msg = buf_msg(tunnel_buf);
2501 	u32 msg_typ = msg_type(tunnel_msg);
2502 	u32 msg_count = msg_msgcnt(tunnel_msg);
2503 
2504 	dest_link = (*l_ptr)->owner->links[msg_bearer_id(tunnel_msg)];
2505 	if (!dest_link) {
2506 		msg_dbg(tunnel_msg, "NOLINK/<REC<");
2507 		goto exit;
2508 	}
2509 	if (dest_link == *l_ptr) {
2510 		err("Unexpected changeover message on link <%s>\n",
2511 		    (*l_ptr)->name);
2512 		goto exit;
2513 	}
2514 	dbg("%c<-%c:", dest_link->b_ptr->net_plane,
2515 	    (*l_ptr)->b_ptr->net_plane);
2516 	*l_ptr = dest_link;
2517 	msg = msg_get_wrapped(tunnel_msg);
2518 
2519 	if (msg_typ == DUPLICATE_MSG) {
2520 		if (less(msg_seqno(msg), mod(dest_link->next_in_no))) {
2521 			msg_dbg(tunnel_msg, "DROP/<REC<");
2522 			goto exit;
2523 		}
2524 		*buf = buf_extract(tunnel_buf,INT_H_SIZE);
2525 		if (*buf == NULL) {
2526 			warn("Link changeover error, duplicate msg dropped\n");
2527 			goto exit;
2528 		}
2529 		msg_dbg(tunnel_msg, "TNL<REC<");
2530 		buf_discard(tunnel_buf);
2531 		return 1;
2532 	}
2533 
2534 	/* First original message ?: */
2535 
2536 	if (tipc_link_is_up(dest_link)) {
2537 		msg_dbg(tunnel_msg, "UP/FIRST/<REC<");
2538 		info("Resetting link <%s>, changeover initiated by peer\n",
2539 		     dest_link->name);
2540 		tipc_link_reset(dest_link);
2541 		dest_link->exp_msg_count = msg_count;
2542 		dbg("Expecting %u tunnelled messages\n", msg_count);
2543 		if (!msg_count)
2544 			goto exit;
2545 	} else if (dest_link->exp_msg_count == START_CHANGEOVER) {
2546 		msg_dbg(tunnel_msg, "BLK/FIRST/<REC<");
2547 		dest_link->exp_msg_count = msg_count;
2548 		dbg("Expecting %u tunnelled messages\n", msg_count);
2549 		if (!msg_count)
2550 			goto exit;
2551 	}
2552 
2553 	/* Receive original message */
2554 
2555 	if (dest_link->exp_msg_count == 0) {
2556 		warn("Link switchover error, "
2557 		     "got too many tunnelled messages\n");
2558 		msg_dbg(tunnel_msg, "OVERDUE/DROP/<REC<");
2559 		dbg_print_link(dest_link, "LINK:");
2560 		goto exit;
2561 	}
2562 	dest_link->exp_msg_count--;
2563 	if (less(msg_seqno(msg), dest_link->reset_checkpoint)) {
2564 		msg_dbg(tunnel_msg, "DROP/DUPL/<REC<");
2565 		goto exit;
2566 	} else {
2567 		*buf = buf_extract(tunnel_buf, INT_H_SIZE);
2568 		if (*buf != NULL) {
2569 			msg_dbg(tunnel_msg, "TNL<REC<");
2570 			buf_discard(tunnel_buf);
2571 			return 1;
2572 		} else {
2573 			warn("Link changeover error, original msg dropped\n");
2574 		}
2575 	}
2576 exit:
2577 	*buf = NULL;
2578 	buf_discard(tunnel_buf);
2579 	return 0;
2580 }
2581 
2582 /*
2583  *  Bundler functionality:
2584  */
2585 void tipc_link_recv_bundle(struct sk_buff *buf)
2586 {
2587 	u32 msgcount = msg_msgcnt(buf_msg(buf));
2588 	u32 pos = INT_H_SIZE;
2589 	struct sk_buff *obuf;
2590 
2591 	msg_dbg(buf_msg(buf), "<BNDL<: ");
2592 	while (msgcount--) {
2593 		obuf = buf_extract(buf, pos);
2594 		if (obuf == NULL) {
2595 			warn("Link unable to unbundle message(s)\n");
2596 			break;
2597 		}
2598 		pos += align(msg_size(buf_msg(obuf)));
2599 		msg_dbg(buf_msg(obuf), "     /");
2600 		tipc_net_route_msg(obuf);
2601 	}
2602 	buf_discard(buf);
2603 }
2604 
2605 /*
2606  *  Fragmentation/defragmentation:
2607  */
2608 
2609 
2610 /*
2611  * link_send_long_buf: Entry for buffers needing fragmentation.
2612  * The buffer is complete, inclusive total message length.
2613  * Returns user data length.
2614  */
2615 static int link_send_long_buf(struct link *l_ptr, struct sk_buff *buf)
2616 {
2617 	struct tipc_msg *inmsg = buf_msg(buf);
2618 	struct tipc_msg fragm_hdr;
2619 	u32 insize = msg_size(inmsg);
2620 	u32 dsz = msg_data_sz(inmsg);
2621 	unchar *crs = buf->data;
2622 	u32 rest = insize;
2623 	u32 pack_sz = l_ptr->max_pkt;
2624 	u32 fragm_sz = pack_sz - INT_H_SIZE;
2625 	u32 fragm_no = 1;
2626 	u32 destaddr;
2627 
2628 	if (msg_short(inmsg))
2629 		destaddr = l_ptr->addr;
2630 	else
2631 		destaddr = msg_destnode(inmsg);
2632 
2633 	if (msg_routed(inmsg))
2634 		msg_set_prevnode(inmsg, tipc_own_addr);
2635 
2636 	/* Prepare reusable fragment header: */
2637 
2638 	tipc_msg_init(&fragm_hdr, MSG_FRAGMENTER, FIRST_FRAGMENT,
2639 		 INT_H_SIZE, destaddr);
2640 	msg_set_link_selector(&fragm_hdr, msg_link_selector(inmsg));
2641 	msg_set_long_msgno(&fragm_hdr, mod(l_ptr->long_msg_seq_no++));
2642 	msg_set_fragm_no(&fragm_hdr, fragm_no);
2643 	l_ptr->stats.sent_fragmented++;
2644 
2645 	/* Chop up message: */
2646 
2647 	while (rest > 0) {
2648 		struct sk_buff *fragm;
2649 
2650 		if (rest <= fragm_sz) {
2651 			fragm_sz = rest;
2652 			msg_set_type(&fragm_hdr, LAST_FRAGMENT);
2653 		}
2654 		fragm = tipc_buf_acquire(fragm_sz + INT_H_SIZE);
2655 		if (fragm == NULL) {
2656 			warn("Link unable to fragment message\n");
2657 			dsz = -ENOMEM;
2658 			goto exit;
2659 		}
2660 		msg_set_size(&fragm_hdr, fragm_sz + INT_H_SIZE);
2661 		skb_copy_to_linear_data(fragm, &fragm_hdr, INT_H_SIZE);
2662 		skb_copy_to_linear_data_offset(fragm, INT_H_SIZE, crs,
2663 					       fragm_sz);
2664 		/*  Send queued messages first, if any: */
2665 
2666 		l_ptr->stats.sent_fragments++;
2667 		tipc_link_send_buf(l_ptr, fragm);
2668 		if (!tipc_link_is_up(l_ptr))
2669 			return dsz;
2670 		msg_set_fragm_no(&fragm_hdr, ++fragm_no);
2671 		rest -= fragm_sz;
2672 		crs += fragm_sz;
2673 		msg_set_type(&fragm_hdr, FRAGMENT);
2674 	}
2675 exit:
2676 	buf_discard(buf);
2677 	return dsz;
2678 }
2679 
2680 /*
2681  * A pending message being re-assembled must store certain values
2682  * to handle subsequent fragments correctly. The following functions
2683  * help storing these values in unused, available fields in the
2684  * pending message. This makes dynamic memory allocation unecessary.
2685  */
2686 
2687 static void set_long_msg_seqno(struct sk_buff *buf, u32 seqno)
2688 {
2689 	msg_set_seqno(buf_msg(buf), seqno);
2690 }
2691 
2692 static u32 get_fragm_size(struct sk_buff *buf)
2693 {
2694 	return msg_ack(buf_msg(buf));
2695 }
2696 
2697 static void set_fragm_size(struct sk_buff *buf, u32 sz)
2698 {
2699 	msg_set_ack(buf_msg(buf), sz);
2700 }
2701 
2702 static u32 get_expected_frags(struct sk_buff *buf)
2703 {
2704 	return msg_bcast_ack(buf_msg(buf));
2705 }
2706 
2707 static void set_expected_frags(struct sk_buff *buf, u32 exp)
2708 {
2709 	msg_set_bcast_ack(buf_msg(buf), exp);
2710 }
2711 
2712 static u32 get_timer_cnt(struct sk_buff *buf)
2713 {
2714 	return msg_reroute_cnt(buf_msg(buf));
2715 }
2716 
2717 static void incr_timer_cnt(struct sk_buff *buf)
2718 {
2719 	msg_incr_reroute_cnt(buf_msg(buf));
2720 }
2721 
2722 /*
2723  * tipc_link_recv_fragment(): Called with node lock on. Returns
2724  * the reassembled buffer if message is complete.
2725  */
2726 int tipc_link_recv_fragment(struct sk_buff **pending, struct sk_buff **fb,
2727 			    struct tipc_msg **m)
2728 {
2729 	struct sk_buff *prev = NULL;
2730 	struct sk_buff *fbuf = *fb;
2731 	struct tipc_msg *fragm = buf_msg(fbuf);
2732 	struct sk_buff *pbuf = *pending;
2733 	u32 long_msg_seq_no = msg_long_msgno(fragm);
2734 
2735 	*fb = NULL;
2736 	msg_dbg(fragm,"FRG<REC<");
2737 
2738 	/* Is there an incomplete message waiting for this fragment? */
2739 
2740 	while (pbuf && ((msg_seqno(buf_msg(pbuf)) != long_msg_seq_no) ||
2741 			(msg_orignode(fragm) != msg_orignode(buf_msg(pbuf))))) {
2742 		prev = pbuf;
2743 		pbuf = pbuf->next;
2744 	}
2745 
2746 	if (!pbuf && (msg_type(fragm) == FIRST_FRAGMENT)) {
2747 		struct tipc_msg *imsg = (struct tipc_msg *)msg_data(fragm);
2748 		u32 msg_sz = msg_size(imsg);
2749 		u32 fragm_sz = msg_data_sz(fragm);
2750 		u32 exp_fragm_cnt = msg_sz/fragm_sz + !!(msg_sz % fragm_sz);
2751 		u32 max =  TIPC_MAX_USER_MSG_SIZE + LONG_H_SIZE;
2752 		if (msg_type(imsg) == TIPC_MCAST_MSG)
2753 			max = TIPC_MAX_USER_MSG_SIZE + MCAST_H_SIZE;
2754 		if (msg_size(imsg) > max) {
2755 			msg_dbg(fragm,"<REC<Oversized: ");
2756 			buf_discard(fbuf);
2757 			return 0;
2758 		}
2759 		pbuf = tipc_buf_acquire(msg_size(imsg));
2760 		if (pbuf != NULL) {
2761 			pbuf->next = *pending;
2762 			*pending = pbuf;
2763 			skb_copy_to_linear_data(pbuf, imsg,
2764 						msg_data_sz(fragm));
2765 			/*  Prepare buffer for subsequent fragments. */
2766 
2767 			set_long_msg_seqno(pbuf, long_msg_seq_no);
2768 			set_fragm_size(pbuf,fragm_sz);
2769 			set_expected_frags(pbuf,exp_fragm_cnt - 1);
2770 		} else {
2771 			warn("Link unable to reassemble fragmented message\n");
2772 		}
2773 		buf_discard(fbuf);
2774 		return 0;
2775 	} else if (pbuf && (msg_type(fragm) != FIRST_FRAGMENT)) {
2776 		u32 dsz = msg_data_sz(fragm);
2777 		u32 fsz = get_fragm_size(pbuf);
2778 		u32 crs = ((msg_fragm_no(fragm) - 1) * fsz);
2779 		u32 exp_frags = get_expected_frags(pbuf) - 1;
2780 		skb_copy_to_linear_data_offset(pbuf, crs,
2781 					       msg_data(fragm), dsz);
2782 		buf_discard(fbuf);
2783 
2784 		/* Is message complete? */
2785 
2786 		if (exp_frags == 0) {
2787 			if (prev)
2788 				prev->next = pbuf->next;
2789 			else
2790 				*pending = pbuf->next;
2791 			msg_reset_reroute_cnt(buf_msg(pbuf));
2792 			*fb = pbuf;
2793 			*m = buf_msg(pbuf);
2794 			return 1;
2795 		}
2796 		set_expected_frags(pbuf,exp_frags);
2797 		return 0;
2798 	}
2799 	dbg(" Discarding orphan fragment %x\n",fbuf);
2800 	msg_dbg(fragm,"ORPHAN:");
2801 	dbg("Pending long buffers:\n");
2802 	dbg_print_buf_chain(*pending);
2803 	buf_discard(fbuf);
2804 	return 0;
2805 }
2806 
2807 /**
2808  * link_check_defragm_bufs - flush stale incoming message fragments
2809  * @l_ptr: pointer to link
2810  */
2811 
2812 static void link_check_defragm_bufs(struct link *l_ptr)
2813 {
2814 	struct sk_buff *prev = NULL;
2815 	struct sk_buff *next = NULL;
2816 	struct sk_buff *buf = l_ptr->defragm_buf;
2817 
2818 	if (!buf)
2819 		return;
2820 	if (!link_working_working(l_ptr))
2821 		return;
2822 	while (buf) {
2823 		u32 cnt = get_timer_cnt(buf);
2824 
2825 		next = buf->next;
2826 		if (cnt < 4) {
2827 			incr_timer_cnt(buf);
2828 			prev = buf;
2829 		} else {
2830 			dbg(" Discarding incomplete long buffer\n");
2831 			msg_dbg(buf_msg(buf), "LONG:");
2832 			dbg_print_link(l_ptr, "curr:");
2833 			dbg("Pending long buffers:\n");
2834 			dbg_print_buf_chain(l_ptr->defragm_buf);
2835 			if (prev)
2836 				prev->next = buf->next;
2837 			else
2838 				l_ptr->defragm_buf = buf->next;
2839 			buf_discard(buf);
2840 		}
2841 		buf = next;
2842 	}
2843 }
2844 
2845 
2846 
2847 static void link_set_supervision_props(struct link *l_ptr, u32 tolerance)
2848 {
2849 	l_ptr->tolerance = tolerance;
2850 	l_ptr->continuity_interval =
2851 		((tolerance / 4) > 500) ? 500 : tolerance / 4;
2852 	l_ptr->abort_limit = tolerance / (l_ptr->continuity_interval / 4);
2853 }
2854 
2855 
2856 void tipc_link_set_queue_limits(struct link *l_ptr, u32 window)
2857 {
2858 	/* Data messages from this node, inclusive FIRST_FRAGM */
2859 	l_ptr->queue_limit[TIPC_LOW_IMPORTANCE] = window;
2860 	l_ptr->queue_limit[TIPC_MEDIUM_IMPORTANCE] = (window / 3) * 4;
2861 	l_ptr->queue_limit[TIPC_HIGH_IMPORTANCE] = (window / 3) * 5;
2862 	l_ptr->queue_limit[TIPC_CRITICAL_IMPORTANCE] = (window / 3) * 6;
2863 	/* Transiting data messages,inclusive FIRST_FRAGM */
2864 	l_ptr->queue_limit[TIPC_LOW_IMPORTANCE + 4] = 300;
2865 	l_ptr->queue_limit[TIPC_MEDIUM_IMPORTANCE + 4] = 600;
2866 	l_ptr->queue_limit[TIPC_HIGH_IMPORTANCE + 4] = 900;
2867 	l_ptr->queue_limit[TIPC_CRITICAL_IMPORTANCE + 4] = 1200;
2868 	l_ptr->queue_limit[CONN_MANAGER] = 1200;
2869 	l_ptr->queue_limit[ROUTE_DISTRIBUTOR] = 1200;
2870 	l_ptr->queue_limit[CHANGEOVER_PROTOCOL] = 2500;
2871 	l_ptr->queue_limit[NAME_DISTRIBUTOR] = 3000;
2872 	/* FRAGMENT and LAST_FRAGMENT packets */
2873 	l_ptr->queue_limit[MSG_FRAGMENTER] = 4000;
2874 }
2875 
2876 /**
2877  * link_find_link - locate link by name
2878  * @name - ptr to link name string
2879  * @node - ptr to area to be filled with ptr to associated node
2880  *
2881  * Caller must hold 'tipc_net_lock' to ensure node and bearer are not deleted;
2882  * this also prevents link deletion.
2883  *
2884  * Returns pointer to link (or 0 if invalid link name).
2885  */
2886 
2887 static struct link *link_find_link(const char *name, struct tipc_node **node)
2888 {
2889 	struct link_name link_name_parts;
2890 	struct bearer *b_ptr;
2891 	struct link *l_ptr;
2892 
2893 	if (!link_name_validate(name, &link_name_parts))
2894 		return NULL;
2895 
2896 	b_ptr = tipc_bearer_find_interface(link_name_parts.if_local);
2897 	if (!b_ptr)
2898 		return NULL;
2899 
2900 	*node = tipc_node_find(link_name_parts.addr_peer);
2901 	if (!*node)
2902 		return NULL;
2903 
2904 	l_ptr = (*node)->links[b_ptr->identity];
2905 	if (!l_ptr || strcmp(l_ptr->name, name))
2906 		return NULL;
2907 
2908 	return l_ptr;
2909 }
2910 
2911 struct sk_buff *tipc_link_cmd_config(const void *req_tlv_area, int req_tlv_space,
2912 				     u16 cmd)
2913 {
2914 	struct tipc_link_config *args;
2915 	u32 new_value;
2916 	struct link *l_ptr;
2917 	struct tipc_node *node;
2918 	int res;
2919 
2920 	if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_CONFIG))
2921 		return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2922 
2923 	args = (struct tipc_link_config *)TLV_DATA(req_tlv_area);
2924 	new_value = ntohl(args->value);
2925 
2926 	if (!strcmp(args->name, tipc_bclink_name)) {
2927 		if ((cmd == TIPC_CMD_SET_LINK_WINDOW) &&
2928 		    (tipc_bclink_set_queue_limits(new_value) == 0))
2929 			return tipc_cfg_reply_none();
2930 		return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
2931 						   " (cannot change setting on broadcast link)");
2932 	}
2933 
2934 	read_lock_bh(&tipc_net_lock);
2935 	l_ptr = link_find_link(args->name, &node);
2936 	if (!l_ptr) {
2937 		read_unlock_bh(&tipc_net_lock);
2938 		return tipc_cfg_reply_error_string("link not found");
2939 	}
2940 
2941 	tipc_node_lock(node);
2942 	res = -EINVAL;
2943 	switch (cmd) {
2944 	case TIPC_CMD_SET_LINK_TOL:
2945 		if ((new_value >= TIPC_MIN_LINK_TOL) &&
2946 		    (new_value <= TIPC_MAX_LINK_TOL)) {
2947 			link_set_supervision_props(l_ptr, new_value);
2948 			tipc_link_send_proto_msg(l_ptr, STATE_MSG,
2949 						 0, 0, new_value, 0, 0);
2950 			res = 0;
2951 		}
2952 		break;
2953 	case TIPC_CMD_SET_LINK_PRI:
2954 		if ((new_value >= TIPC_MIN_LINK_PRI) &&
2955 		    (new_value <= TIPC_MAX_LINK_PRI)) {
2956 			l_ptr->priority = new_value;
2957 			tipc_link_send_proto_msg(l_ptr, STATE_MSG,
2958 						 0, 0, 0, new_value, 0);
2959 			res = 0;
2960 		}
2961 		break;
2962 	case TIPC_CMD_SET_LINK_WINDOW:
2963 		if ((new_value >= TIPC_MIN_LINK_WIN) &&
2964 		    (new_value <= TIPC_MAX_LINK_WIN)) {
2965 			tipc_link_set_queue_limits(l_ptr, new_value);
2966 			res = 0;
2967 		}
2968 		break;
2969 	}
2970 	tipc_node_unlock(node);
2971 
2972 	read_unlock_bh(&tipc_net_lock);
2973 	if (res)
2974 		return tipc_cfg_reply_error_string("cannot change link setting");
2975 
2976 	return tipc_cfg_reply_none();
2977 }
2978 
2979 /**
2980  * link_reset_statistics - reset link statistics
2981  * @l_ptr: pointer to link
2982  */
2983 
2984 static void link_reset_statistics(struct link *l_ptr)
2985 {
2986 	memset(&l_ptr->stats, 0, sizeof(l_ptr->stats));
2987 	l_ptr->stats.sent_info = l_ptr->next_out_no;
2988 	l_ptr->stats.recv_info = l_ptr->next_in_no;
2989 }
2990 
2991 struct sk_buff *tipc_link_cmd_reset_stats(const void *req_tlv_area, int req_tlv_space)
2992 {
2993 	char *link_name;
2994 	struct link *l_ptr;
2995 	struct tipc_node *node;
2996 
2997 	if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_NAME))
2998 		return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2999 
3000 	link_name = (char *)TLV_DATA(req_tlv_area);
3001 	if (!strcmp(link_name, tipc_bclink_name)) {
3002 		if (tipc_bclink_reset_stats())
3003 			return tipc_cfg_reply_error_string("link not found");
3004 		return tipc_cfg_reply_none();
3005 	}
3006 
3007 	read_lock_bh(&tipc_net_lock);
3008 	l_ptr = link_find_link(link_name, &node);
3009 	if (!l_ptr) {
3010 		read_unlock_bh(&tipc_net_lock);
3011 		return tipc_cfg_reply_error_string("link not found");
3012 	}
3013 
3014 	tipc_node_lock(node);
3015 	link_reset_statistics(l_ptr);
3016 	tipc_node_unlock(node);
3017 	read_unlock_bh(&tipc_net_lock);
3018 	return tipc_cfg_reply_none();
3019 }
3020 
3021 /**
3022  * percent - convert count to a percentage of total (rounding up or down)
3023  */
3024 
3025 static u32 percent(u32 count, u32 total)
3026 {
3027 	return (count * 100 + (total / 2)) / total;
3028 }
3029 
3030 /**
3031  * tipc_link_stats - print link statistics
3032  * @name: link name
3033  * @buf: print buffer area
3034  * @buf_size: size of print buffer area
3035  *
3036  * Returns length of print buffer data string (or 0 if error)
3037  */
3038 
3039 static int tipc_link_stats(const char *name, char *buf, const u32 buf_size)
3040 {
3041 	struct print_buf pb;
3042 	struct link *l_ptr;
3043 	struct tipc_node *node;
3044 	char *status;
3045 	u32 profile_total = 0;
3046 
3047 	if (!strcmp(name, tipc_bclink_name))
3048 		return tipc_bclink_stats(buf, buf_size);
3049 
3050 	tipc_printbuf_init(&pb, buf, buf_size);
3051 
3052 	read_lock_bh(&tipc_net_lock);
3053 	l_ptr = link_find_link(name, &node);
3054 	if (!l_ptr) {
3055 		read_unlock_bh(&tipc_net_lock);
3056 		return 0;
3057 	}
3058 	tipc_node_lock(node);
3059 
3060 	if (tipc_link_is_active(l_ptr))
3061 		status = "ACTIVE";
3062 	else if (tipc_link_is_up(l_ptr))
3063 		status = "STANDBY";
3064 	else
3065 		status = "DEFUNCT";
3066 	tipc_printf(&pb, "Link <%s>\n"
3067 			 "  %s  MTU:%u  Priority:%u  Tolerance:%u ms"
3068 			 "  Window:%u packets\n",
3069 		    l_ptr->name, status, l_ptr->max_pkt,
3070 		    l_ptr->priority, l_ptr->tolerance, l_ptr->queue_limit[0]);
3071 	tipc_printf(&pb, "  RX packets:%u fragments:%u/%u bundles:%u/%u\n",
3072 		    l_ptr->next_in_no - l_ptr->stats.recv_info,
3073 		    l_ptr->stats.recv_fragments,
3074 		    l_ptr->stats.recv_fragmented,
3075 		    l_ptr->stats.recv_bundles,
3076 		    l_ptr->stats.recv_bundled);
3077 	tipc_printf(&pb, "  TX packets:%u fragments:%u/%u bundles:%u/%u\n",
3078 		    l_ptr->next_out_no - l_ptr->stats.sent_info,
3079 		    l_ptr->stats.sent_fragments,
3080 		    l_ptr->stats.sent_fragmented,
3081 		    l_ptr->stats.sent_bundles,
3082 		    l_ptr->stats.sent_bundled);
3083 	profile_total = l_ptr->stats.msg_length_counts;
3084 	if (!profile_total)
3085 		profile_total = 1;
3086 	tipc_printf(&pb, "  TX profile sample:%u packets  average:%u octets\n"
3087 			 "  0-64:%u%% -256:%u%% -1024:%u%% -4096:%u%% "
3088 			 "-16354:%u%% -32768:%u%% -66000:%u%%\n",
3089 		    l_ptr->stats.msg_length_counts,
3090 		    l_ptr->stats.msg_lengths_total / profile_total,
3091 		    percent(l_ptr->stats.msg_length_profile[0], profile_total),
3092 		    percent(l_ptr->stats.msg_length_profile[1], profile_total),
3093 		    percent(l_ptr->stats.msg_length_profile[2], profile_total),
3094 		    percent(l_ptr->stats.msg_length_profile[3], profile_total),
3095 		    percent(l_ptr->stats.msg_length_profile[4], profile_total),
3096 		    percent(l_ptr->stats.msg_length_profile[5], profile_total),
3097 		    percent(l_ptr->stats.msg_length_profile[6], profile_total));
3098 	tipc_printf(&pb, "  RX states:%u probes:%u naks:%u defs:%u dups:%u\n",
3099 		    l_ptr->stats.recv_states,
3100 		    l_ptr->stats.recv_probes,
3101 		    l_ptr->stats.recv_nacks,
3102 		    l_ptr->stats.deferred_recv,
3103 		    l_ptr->stats.duplicates);
3104 	tipc_printf(&pb, "  TX states:%u probes:%u naks:%u acks:%u dups:%u\n",
3105 		    l_ptr->stats.sent_states,
3106 		    l_ptr->stats.sent_probes,
3107 		    l_ptr->stats.sent_nacks,
3108 		    l_ptr->stats.sent_acks,
3109 		    l_ptr->stats.retransmitted);
3110 	tipc_printf(&pb, "  Congestion bearer:%u link:%u  Send queue max:%u avg:%u\n",
3111 		    l_ptr->stats.bearer_congs,
3112 		    l_ptr->stats.link_congs,
3113 		    l_ptr->stats.max_queue_sz,
3114 		    l_ptr->stats.queue_sz_counts
3115 		    ? (l_ptr->stats.accu_queue_sz / l_ptr->stats.queue_sz_counts)
3116 		    : 0);
3117 
3118 	tipc_node_unlock(node);
3119 	read_unlock_bh(&tipc_net_lock);
3120 	return tipc_printbuf_validate(&pb);
3121 }
3122 
3123 #define MAX_LINK_STATS_INFO 2000
3124 
3125 struct sk_buff *tipc_link_cmd_show_stats(const void *req_tlv_area, int req_tlv_space)
3126 {
3127 	struct sk_buff *buf;
3128 	struct tlv_desc *rep_tlv;
3129 	int str_len;
3130 
3131 	if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_NAME))
3132 		return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
3133 
3134 	buf = tipc_cfg_reply_alloc(TLV_SPACE(MAX_LINK_STATS_INFO));
3135 	if (!buf)
3136 		return NULL;
3137 
3138 	rep_tlv = (struct tlv_desc *)buf->data;
3139 
3140 	str_len = tipc_link_stats((char *)TLV_DATA(req_tlv_area),
3141 				  (char *)TLV_DATA(rep_tlv), MAX_LINK_STATS_INFO);
3142 	if (!str_len) {
3143 		buf_discard(buf);
3144 		return tipc_cfg_reply_error_string("link not found");
3145 	}
3146 
3147 	skb_put(buf, TLV_SPACE(str_len));
3148 	TLV_SET(rep_tlv, TIPC_TLV_ULTRA_STRING, NULL, str_len);
3149 
3150 	return buf;
3151 }
3152 
3153 /**
3154  * tipc_link_get_max_pkt - get maximum packet size to use when sending to destination
3155  * @dest: network address of destination node
3156  * @selector: used to select from set of active links
3157  *
3158  * If no active link can be found, uses default maximum packet size.
3159  */
3160 
3161 u32 tipc_link_get_max_pkt(u32 dest, u32 selector)
3162 {
3163 	struct tipc_node *n_ptr;
3164 	struct link *l_ptr;
3165 	u32 res = MAX_PKT_DEFAULT;
3166 
3167 	if (dest == tipc_own_addr)
3168 		return MAX_MSG_SIZE;
3169 
3170 	read_lock_bh(&tipc_net_lock);
3171 	n_ptr = tipc_node_select(dest, selector);
3172 	if (n_ptr) {
3173 		tipc_node_lock(n_ptr);
3174 		l_ptr = n_ptr->active_links[selector & 1];
3175 		if (l_ptr)
3176 			res = l_ptr->max_pkt;
3177 		tipc_node_unlock(n_ptr);
3178 	}
3179 	read_unlock_bh(&tipc_net_lock);
3180 	return res;
3181 }
3182 
3183 static void link_dump_send_queue(struct link *l_ptr)
3184 {
3185 	if (l_ptr->next_out) {
3186 		info("\nContents of unsent queue:\n");
3187 		dbg_print_buf_chain(l_ptr->next_out);
3188 	}
3189 	info("\nContents of send queue:\n");
3190 	if (l_ptr->first_out) {
3191 		dbg_print_buf_chain(l_ptr->first_out);
3192 	}
3193 	info("Empty send queue\n");
3194 }
3195 
3196 static void link_print(struct link *l_ptr, struct print_buf *buf,
3197 		       const char *str)
3198 {
3199 	tipc_printf(buf, str);
3200 	if (link_reset_reset(l_ptr) || link_reset_unknown(l_ptr))
3201 		return;
3202 	tipc_printf(buf, "Link %x<%s>:",
3203 		    l_ptr->addr, l_ptr->b_ptr->publ.name);
3204 	tipc_printf(buf, ": NXO(%u):", mod(l_ptr->next_out_no));
3205 	tipc_printf(buf, "NXI(%u):", mod(l_ptr->next_in_no));
3206 	tipc_printf(buf, "SQUE");
3207 	if (l_ptr->first_out) {
3208 		tipc_printf(buf, "[%u..", msg_seqno(buf_msg(l_ptr->first_out)));
3209 		if (l_ptr->next_out)
3210 			tipc_printf(buf, "%u..",
3211 				    msg_seqno(buf_msg(l_ptr->next_out)));
3212 		tipc_printf(buf, "%u]", msg_seqno(buf_msg(l_ptr->last_out)));
3213 		if ((mod(msg_seqno(buf_msg(l_ptr->last_out)) -
3214 			 msg_seqno(buf_msg(l_ptr->first_out)))
3215 		     != (l_ptr->out_queue_size - 1)) ||
3216 		    (l_ptr->last_out->next != NULL)) {
3217 			tipc_printf(buf, "\nSend queue inconsistency\n");
3218 			tipc_printf(buf, "first_out= %x ", l_ptr->first_out);
3219 			tipc_printf(buf, "next_out= %x ", l_ptr->next_out);
3220 			tipc_printf(buf, "last_out= %x ", l_ptr->last_out);
3221 			link_dump_send_queue(l_ptr);
3222 		}
3223 	} else
3224 		tipc_printf(buf, "[]");
3225 	tipc_printf(buf, "SQSIZ(%u)", l_ptr->out_queue_size);
3226 	if (l_ptr->oldest_deferred_in) {
3227 		u32 o = msg_seqno(buf_msg(l_ptr->oldest_deferred_in));
3228 		u32 n = msg_seqno(buf_msg(l_ptr->newest_deferred_in));
3229 		tipc_printf(buf, ":RQUE[%u..%u]", o, n);
3230 		if (l_ptr->deferred_inqueue_sz != mod((n + 1) - o)) {
3231 			tipc_printf(buf, ":RQSIZ(%u)",
3232 				    l_ptr->deferred_inqueue_sz);
3233 		}
3234 	}
3235 	if (link_working_unknown(l_ptr))
3236 		tipc_printf(buf, ":WU");
3237 	if (link_reset_reset(l_ptr))
3238 		tipc_printf(buf, ":RR");
3239 	if (link_reset_unknown(l_ptr))
3240 		tipc_printf(buf, ":RU");
3241 	if (link_working_working(l_ptr))
3242 		tipc_printf(buf, ":WW");
3243 	tipc_printf(buf, "\n");
3244 }
3245 
3246