xref: /linux/net/tipc/link.c (revision 14b42963f64b98ab61fa9723c03d71aa5ef4f862)
1 /*
2  * net/tipc/link.c: TIPC link code
3  *
4  * Copyright (c) 1996-2006, Ericsson AB
5  * Copyright (c) 2004-2006, 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  * Limit for deferred reception queue:
55  */
56 
57 #define DEF_QUEUE_LIMIT 256u
58 
59 /*
60  * Link state events:
61  */
62 
63 #define  STARTING_EVT    856384768	/* link processing trigger */
64 #define  TRAFFIC_MSG_EVT 560815u	/* rx'd ??? */
65 #define  TIMEOUT_EVT     560817u	/* link timer expired */
66 
67 /*
68  * The following two 'message types' is really just implementation
69  * data conveniently stored in the message header.
70  * They must not be considered part of the protocol
71  */
72 #define OPEN_MSG   0
73 #define CLOSED_MSG 1
74 
75 /*
76  * State value stored in 'exp_msg_count'
77  */
78 
79 #define START_CHANGEOVER 100000u
80 
81 /**
82  * struct link_name - deconstructed link name
83  * @addr_local: network address of node at this end
84  * @if_local: name of interface at this end
85  * @addr_peer: network address of node at far end
86  * @if_peer: name of interface at far end
87  */
88 
89 struct link_name {
90 	u32 addr_local;
91 	char if_local[TIPC_MAX_IF_NAME];
92 	u32 addr_peer;
93 	char if_peer[TIPC_MAX_IF_NAME];
94 };
95 
96 #if 0
97 
98 /* LINK EVENT CODE IS NOT SUPPORTED AT PRESENT */
99 
100 /**
101  * struct link_event - link up/down event notification
102  */
103 
104 struct link_event {
105 	u32 addr;
106 	int up;
107 	void (*fcn)(u32, char *, int);
108 	char name[TIPC_MAX_LINK_NAME];
109 };
110 
111 #endif
112 
113 static void link_handle_out_of_seq_msg(struct link *l_ptr,
114 				       struct sk_buff *buf);
115 static void link_recv_proto_msg(struct link *l_ptr, struct sk_buff *buf);
116 static int  link_recv_changeover_msg(struct link **l_ptr, struct sk_buff **buf);
117 static void link_set_supervision_props(struct link *l_ptr, u32 tolerance);
118 static int  link_send_sections_long(struct port *sender,
119 				    struct iovec const *msg_sect,
120 				    u32 num_sect, u32 destnode);
121 static void link_check_defragm_bufs(struct link *l_ptr);
122 static void link_state_event(struct link *l_ptr, u32 event);
123 static void link_reset_statistics(struct link *l_ptr);
124 static void link_print(struct link *l_ptr, struct print_buf *buf,
125 		       const char *str);
126 
127 /*
128  * Debugging code used by link routines only
129  *
130  * When debugging link problems on a system that has multiple links,
131  * the standard TIPC debugging routines may not be useful since they
132  * allow the output from multiple links to be intermixed.  For this reason
133  * routines of the form "dbg_link_XXX()" have been created that will capture
134  * debug info into a link's personal print buffer, which can then be dumped
135  * into the TIPC system log (LOG) upon request.
136  *
137  * To enable per-link debugging, use LINK_LOG_BUF_SIZE to specify the size
138  * of the print buffer used by each link.  If LINK_LOG_BUF_SIZE is set to 0,
139  * the dbg_link_XXX() routines simply send their output to the standard
140  * debug print buffer (DBG_OUTPUT), if it has been defined; this can be useful
141  * when there is only a single link in the system being debugged.
142  *
143  * Notes:
144  * - When enabled, LINK_LOG_BUF_SIZE should be set to at least 1000 (bytes)
145  * - "l_ptr" must be valid when using dbg_link_XXX() macros
146  */
147 
148 #define LINK_LOG_BUF_SIZE 0
149 
150 #define dbg_link(fmt, arg...)  do {if (LINK_LOG_BUF_SIZE) tipc_printf(&l_ptr->print_buf, fmt, ## arg); } while(0)
151 #define dbg_link_msg(msg, txt) do {if (LINK_LOG_BUF_SIZE) tipc_msg_print(&l_ptr->print_buf, msg, txt); } while(0)
152 #define dbg_link_state(txt) do {if (LINK_LOG_BUF_SIZE) link_print(l_ptr, &l_ptr->print_buf, txt); } while(0)
153 #define dbg_link_dump() do { \
154 	if (LINK_LOG_BUF_SIZE) { \
155 		tipc_printf(LOG, "\n\nDumping link <%s>:\n", l_ptr->name); \
156 		tipc_printbuf_move(LOG, &l_ptr->print_buf); \
157 	} \
158 } while (0)
159 
160 static void dbg_print_link(struct link *l_ptr, const char *str)
161 {
162 	if (DBG_OUTPUT)
163 		link_print(l_ptr, DBG_OUTPUT, str);
164 }
165 
166 static void dbg_print_buf_chain(struct sk_buff *root_buf)
167 {
168 	if (DBG_OUTPUT) {
169 		struct sk_buff *buf = root_buf;
170 
171 		while (buf) {
172 			msg_dbg(buf_msg(buf), "In chain: ");
173 			buf = buf->next;
174 		}
175 	}
176 }
177 
178 /*
179  *  Simple link routines
180  */
181 
182 static unsigned int align(unsigned int i)
183 {
184 	return (i + 3) & ~3u;
185 }
186 
187 static int link_working_working(struct link *l_ptr)
188 {
189 	return (l_ptr->state == WORKING_WORKING);
190 }
191 
192 static int link_working_unknown(struct link *l_ptr)
193 {
194 	return (l_ptr->state == WORKING_UNKNOWN);
195 }
196 
197 static int link_reset_unknown(struct link *l_ptr)
198 {
199 	return (l_ptr->state == RESET_UNKNOWN);
200 }
201 
202 static int link_reset_reset(struct link *l_ptr)
203 {
204 	return (l_ptr->state == RESET_RESET);
205 }
206 
207 static int link_blocked(struct link *l_ptr)
208 {
209 	return (l_ptr->exp_msg_count || l_ptr->blocked);
210 }
211 
212 static int link_congested(struct link *l_ptr)
213 {
214 	return (l_ptr->out_queue_size >= l_ptr->queue_limit[0]);
215 }
216 
217 static u32 link_max_pkt(struct link *l_ptr)
218 {
219 	return l_ptr->max_pkt;
220 }
221 
222 static void link_init_max_pkt(struct link *l_ptr)
223 {
224 	u32 max_pkt;
225 
226 	max_pkt = (l_ptr->b_ptr->publ.mtu & ~3);
227 	if (max_pkt > MAX_MSG_SIZE)
228 		max_pkt = MAX_MSG_SIZE;
229 
230         l_ptr->max_pkt_target = max_pkt;
231 	if (l_ptr->max_pkt_target < MAX_PKT_DEFAULT)
232 		l_ptr->max_pkt = l_ptr->max_pkt_target;
233 	else
234 		l_ptr->max_pkt = MAX_PKT_DEFAULT;
235 
236         l_ptr->max_pkt_probes = 0;
237 }
238 
239 static u32 link_next_sent(struct link *l_ptr)
240 {
241 	if (l_ptr->next_out)
242 		return msg_seqno(buf_msg(l_ptr->next_out));
243 	return mod(l_ptr->next_out_no);
244 }
245 
246 static u32 link_last_sent(struct link *l_ptr)
247 {
248 	return mod(link_next_sent(l_ptr) - 1);
249 }
250 
251 /*
252  *  Simple non-static link routines (i.e. referenced outside this file)
253  */
254 
255 int tipc_link_is_up(struct link *l_ptr)
256 {
257 	if (!l_ptr)
258 		return 0;
259 	return (link_working_working(l_ptr) || link_working_unknown(l_ptr));
260 }
261 
262 int tipc_link_is_active(struct link *l_ptr)
263 {
264 	return ((l_ptr->owner->active_links[0] == l_ptr) ||
265 		(l_ptr->owner->active_links[1] == l_ptr));
266 }
267 
268 /**
269  * link_name_validate - validate & (optionally) deconstruct link name
270  * @name - ptr to link name string
271  * @name_parts - ptr to area for link name components (or NULL if not needed)
272  *
273  * Returns 1 if link name is valid, otherwise 0.
274  */
275 
276 static int link_name_validate(const char *name, struct link_name *name_parts)
277 {
278 	char name_copy[TIPC_MAX_LINK_NAME];
279 	char *addr_local;
280 	char *if_local;
281 	char *addr_peer;
282 	char *if_peer;
283 	char dummy;
284 	u32 z_local, c_local, n_local;
285 	u32 z_peer, c_peer, n_peer;
286 	u32 if_local_len;
287 	u32 if_peer_len;
288 
289 	/* copy link name & ensure length is OK */
290 
291 	name_copy[TIPC_MAX_LINK_NAME - 1] = 0;
292 	/* need above in case non-Posix strncpy() doesn't pad with nulls */
293 	strncpy(name_copy, name, TIPC_MAX_LINK_NAME);
294 	if (name_copy[TIPC_MAX_LINK_NAME - 1] != 0)
295 		return 0;
296 
297 	/* ensure all component parts of link name are present */
298 
299 	addr_local = name_copy;
300 	if ((if_local = strchr(addr_local, ':')) == NULL)
301 		return 0;
302 	*(if_local++) = 0;
303 	if ((addr_peer = strchr(if_local, '-')) == NULL)
304 		return 0;
305 	*(addr_peer++) = 0;
306 	if_local_len = addr_peer - if_local;
307 	if ((if_peer = strchr(addr_peer, ':')) == NULL)
308 		return 0;
309 	*(if_peer++) = 0;
310 	if_peer_len = strlen(if_peer) + 1;
311 
312 	/* validate component parts of link name */
313 
314 	if ((sscanf(addr_local, "%u.%u.%u%c",
315 		    &z_local, &c_local, &n_local, &dummy) != 3) ||
316 	    (sscanf(addr_peer, "%u.%u.%u%c",
317 		    &z_peer, &c_peer, &n_peer, &dummy) != 3) ||
318 	    (z_local > 255) || (c_local > 4095) || (n_local > 4095) ||
319 	    (z_peer  > 255) || (c_peer  > 4095) || (n_peer  > 4095) ||
320 	    (if_local_len <= 1) || (if_local_len > TIPC_MAX_IF_NAME) ||
321 	    (if_peer_len  <= 1) || (if_peer_len  > TIPC_MAX_IF_NAME) ||
322 	    (strspn(if_local, tipc_alphabet) != (if_local_len - 1)) ||
323 	    (strspn(if_peer, tipc_alphabet) != (if_peer_len - 1)))
324 		return 0;
325 
326 	/* return link name components, if necessary */
327 
328 	if (name_parts) {
329 		name_parts->addr_local = tipc_addr(z_local, c_local, n_local);
330 		strcpy(name_parts->if_local, if_local);
331 		name_parts->addr_peer = tipc_addr(z_peer, c_peer, n_peer);
332 		strcpy(name_parts->if_peer, if_peer);
333 	}
334 	return 1;
335 }
336 
337 /**
338  * link_timeout - handle expiration of link timer
339  * @l_ptr: pointer to link
340  *
341  * This routine must not grab "tipc_net_lock" to avoid a potential deadlock conflict
342  * with tipc_link_delete().  (There is no risk that the node will be deleted by
343  * another thread because tipc_link_delete() always cancels the link timer before
344  * tipc_node_delete() is called.)
345  */
346 
347 static void link_timeout(struct link *l_ptr)
348 {
349 	tipc_node_lock(l_ptr->owner);
350 
351 	/* update counters used in statistical profiling of send traffic */
352 
353 	l_ptr->stats.accu_queue_sz += l_ptr->out_queue_size;
354 	l_ptr->stats.queue_sz_counts++;
355 
356 	if (l_ptr->out_queue_size > l_ptr->stats.max_queue_sz)
357 		l_ptr->stats.max_queue_sz = l_ptr->out_queue_size;
358 
359 	if (l_ptr->first_out) {
360 		struct tipc_msg *msg = buf_msg(l_ptr->first_out);
361 		u32 length = msg_size(msg);
362 
363 		if ((msg_user(msg) == MSG_FRAGMENTER)
364 		    && (msg_type(msg) == FIRST_FRAGMENT)) {
365 			length = msg_size(msg_get_wrapped(msg));
366 		}
367 		if (length) {
368 			l_ptr->stats.msg_lengths_total += length;
369 			l_ptr->stats.msg_length_counts++;
370 			if (length <= 64)
371 				l_ptr->stats.msg_length_profile[0]++;
372 			else if (length <= 256)
373 				l_ptr->stats.msg_length_profile[1]++;
374 			else if (length <= 1024)
375 				l_ptr->stats.msg_length_profile[2]++;
376 			else if (length <= 4096)
377 				l_ptr->stats.msg_length_profile[3]++;
378 			else if (length <= 16384)
379 				l_ptr->stats.msg_length_profile[4]++;
380 			else if (length <= 32768)
381 				l_ptr->stats.msg_length_profile[5]++;
382 			else
383 				l_ptr->stats.msg_length_profile[6]++;
384 		}
385 	}
386 
387 	/* do all other link processing performed on a periodic basis */
388 
389 	link_check_defragm_bufs(l_ptr);
390 
391 	link_state_event(l_ptr, TIMEOUT_EVT);
392 
393 	if (l_ptr->next_out)
394 		tipc_link_push_queue(l_ptr);
395 
396 	tipc_node_unlock(l_ptr->owner);
397 }
398 
399 static void link_set_timer(struct link *l_ptr, u32 time)
400 {
401 	k_start_timer(&l_ptr->timer, time);
402 }
403 
404 /**
405  * tipc_link_create - create a new link
406  * @b_ptr: pointer to associated bearer
407  * @peer: network address of node at other end of link
408  * @media_addr: media address to use when sending messages over link
409  *
410  * Returns pointer to link.
411  */
412 
413 struct link *tipc_link_create(struct bearer *b_ptr, const u32 peer,
414 			      const struct tipc_media_addr *media_addr)
415 {
416 	struct link *l_ptr;
417 	struct tipc_msg *msg;
418 	char *if_name;
419 
420 	l_ptr = (struct link *)kmalloc(sizeof(*l_ptr), GFP_ATOMIC);
421 	if (!l_ptr) {
422 		warn("Link creation failed, no memory\n");
423 		return NULL;
424 	}
425 	memset(l_ptr, 0, sizeof(*l_ptr));
426 
427 	l_ptr->addr = peer;
428 	if_name = strchr(b_ptr->publ.name, ':') + 1;
429 	sprintf(l_ptr->name, "%u.%u.%u:%s-%u.%u.%u:",
430 		tipc_zone(tipc_own_addr), tipc_cluster(tipc_own_addr),
431 		tipc_node(tipc_own_addr),
432 		if_name,
433 		tipc_zone(peer), tipc_cluster(peer), tipc_node(peer));
434 		/* note: peer i/f is appended to link name by reset/activate */
435 	memcpy(&l_ptr->media_addr, media_addr, sizeof(*media_addr));
436 	k_init_timer(&l_ptr->timer, (Handler)link_timeout, (unsigned long)l_ptr);
437 	list_add_tail(&l_ptr->link_list, &b_ptr->links);
438 	l_ptr->checkpoint = 1;
439 	l_ptr->b_ptr = b_ptr;
440 	link_set_supervision_props(l_ptr, b_ptr->media->tolerance);
441 	l_ptr->state = RESET_UNKNOWN;
442 
443 	l_ptr->pmsg = (struct tipc_msg *)&l_ptr->proto_msg;
444 	msg = l_ptr->pmsg;
445 	msg_init(msg, LINK_PROTOCOL, RESET_MSG, TIPC_OK, INT_H_SIZE, l_ptr->addr);
446 	msg_set_size(msg, sizeof(l_ptr->proto_msg));
447 	msg_set_session(msg, tipc_random);
448 	msg_set_bearer_id(msg, b_ptr->identity);
449 	strcpy((char *)msg_data(msg), if_name);
450 
451 	l_ptr->priority = b_ptr->priority;
452 	tipc_link_set_queue_limits(l_ptr, b_ptr->media->window);
453 
454 	link_init_max_pkt(l_ptr);
455 
456 	l_ptr->next_out_no = 1;
457 	INIT_LIST_HEAD(&l_ptr->waiting_ports);
458 
459 	link_reset_statistics(l_ptr);
460 
461 	l_ptr->owner = tipc_node_attach_link(l_ptr);
462 	if (!l_ptr->owner) {
463 		kfree(l_ptr);
464 		return NULL;
465 	}
466 
467 	if (LINK_LOG_BUF_SIZE) {
468 		char *pb = kmalloc(LINK_LOG_BUF_SIZE, GFP_ATOMIC);
469 
470 		if (!pb) {
471 			kfree(l_ptr);
472 			warn("Link creation failed, no memory for print buffer\n");
473 			return NULL;
474 		}
475 		tipc_printbuf_init(&l_ptr->print_buf, pb, LINK_LOG_BUF_SIZE);
476 	}
477 
478 	tipc_k_signal((Handler)tipc_link_start, (unsigned long)l_ptr);
479 
480 	dbg("tipc_link_create(): tolerance = %u,cont intv = %u, abort_limit = %u\n",
481 	    l_ptr->tolerance, l_ptr->continuity_interval, l_ptr->abort_limit);
482 
483 	return l_ptr;
484 }
485 
486 /**
487  * tipc_link_delete - delete a link
488  * @l_ptr: pointer to link
489  *
490  * Note: 'tipc_net_lock' is write_locked, bearer is locked.
491  * This routine must not grab the node lock until after link timer cancellation
492  * to avoid a potential deadlock situation.
493  */
494 
495 void tipc_link_delete(struct link *l_ptr)
496 {
497 	if (!l_ptr) {
498 		err("Attempt to delete non-existent link\n");
499 		return;
500 	}
501 
502 	dbg("tipc_link_delete()\n");
503 
504 	k_cancel_timer(&l_ptr->timer);
505 
506 	tipc_node_lock(l_ptr->owner);
507 	tipc_link_reset(l_ptr);
508 	tipc_node_detach_link(l_ptr->owner, l_ptr);
509 	tipc_link_stop(l_ptr);
510 	list_del_init(&l_ptr->link_list);
511 	if (LINK_LOG_BUF_SIZE)
512 		kfree(l_ptr->print_buf.buf);
513 	tipc_node_unlock(l_ptr->owner);
514 	k_term_timer(&l_ptr->timer);
515 	kfree(l_ptr);
516 }
517 
518 void tipc_link_start(struct link *l_ptr)
519 {
520 	dbg("tipc_link_start %x\n", l_ptr);
521 	link_state_event(l_ptr, STARTING_EVT);
522 }
523 
524 /**
525  * link_schedule_port - schedule port for deferred sending
526  * @l_ptr: pointer to link
527  * @origport: reference to sending port
528  * @sz: amount of data to be sent
529  *
530  * Schedules port for renewed sending of messages after link congestion
531  * has abated.
532  */
533 
534 static int link_schedule_port(struct link *l_ptr, u32 origport, u32 sz)
535 {
536 	struct port *p_ptr;
537 
538 	spin_lock_bh(&tipc_port_list_lock);
539 	p_ptr = tipc_port_lock(origport);
540 	if (p_ptr) {
541 		if (!p_ptr->wakeup)
542 			goto exit;
543 		if (!list_empty(&p_ptr->wait_list))
544 			goto exit;
545 		p_ptr->congested_link = l_ptr;
546 		p_ptr->publ.congested = 1;
547 		p_ptr->waiting_pkts = 1 + ((sz - 1) / link_max_pkt(l_ptr));
548 		list_add_tail(&p_ptr->wait_list, &l_ptr->waiting_ports);
549 		l_ptr->stats.link_congs++;
550 exit:
551 		tipc_port_unlock(p_ptr);
552 	}
553 	spin_unlock_bh(&tipc_port_list_lock);
554 	return -ELINKCONG;
555 }
556 
557 void tipc_link_wakeup_ports(struct link *l_ptr, int all)
558 {
559 	struct port *p_ptr;
560 	struct port *temp_p_ptr;
561 	int win = l_ptr->queue_limit[0] - l_ptr->out_queue_size;
562 
563 	if (all)
564 		win = 100000;
565 	if (win <= 0)
566 		return;
567 	if (!spin_trylock_bh(&tipc_port_list_lock))
568 		return;
569 	if (link_congested(l_ptr))
570 		goto exit;
571 	list_for_each_entry_safe(p_ptr, temp_p_ptr, &l_ptr->waiting_ports,
572 				 wait_list) {
573 		if (win <= 0)
574 			break;
575 		list_del_init(&p_ptr->wait_list);
576 		p_ptr->congested_link = NULL;
577 		spin_lock_bh(p_ptr->publ.lock);
578 		p_ptr->publ.congested = 0;
579 		p_ptr->wakeup(&p_ptr->publ);
580 		win -= p_ptr->waiting_pkts;
581 		spin_unlock_bh(p_ptr->publ.lock);
582 	}
583 
584 exit:
585 	spin_unlock_bh(&tipc_port_list_lock);
586 }
587 
588 /**
589  * link_release_outqueue - purge link's outbound message queue
590  * @l_ptr: pointer to link
591  */
592 
593 static void link_release_outqueue(struct link *l_ptr)
594 {
595 	struct sk_buff *buf = l_ptr->first_out;
596 	struct sk_buff *next;
597 
598 	while (buf) {
599 		next = buf->next;
600 		buf_discard(buf);
601 		buf = next;
602 	}
603 	l_ptr->first_out = NULL;
604 	l_ptr->out_queue_size = 0;
605 }
606 
607 /**
608  * tipc_link_reset_fragments - purge link's inbound message fragments queue
609  * @l_ptr: pointer to link
610  */
611 
612 void tipc_link_reset_fragments(struct link *l_ptr)
613 {
614 	struct sk_buff *buf = l_ptr->defragm_buf;
615 	struct sk_buff *next;
616 
617 	while (buf) {
618 		next = buf->next;
619 		buf_discard(buf);
620 		buf = next;
621 	}
622 	l_ptr->defragm_buf = NULL;
623 }
624 
625 /**
626  * tipc_link_stop - purge all inbound and outbound messages associated with link
627  * @l_ptr: pointer to link
628  */
629 
630 void tipc_link_stop(struct link *l_ptr)
631 {
632 	struct sk_buff *buf;
633 	struct sk_buff *next;
634 
635 	buf = l_ptr->oldest_deferred_in;
636 	while (buf) {
637 		next = buf->next;
638 		buf_discard(buf);
639 		buf = next;
640 	}
641 
642 	buf = l_ptr->first_out;
643 	while (buf) {
644 		next = buf->next;
645 		buf_discard(buf);
646 		buf = next;
647 	}
648 
649 	tipc_link_reset_fragments(l_ptr);
650 
651 	buf_discard(l_ptr->proto_msg_queue);
652 	l_ptr->proto_msg_queue = NULL;
653 }
654 
655 #if 0
656 
657 /* LINK EVENT CODE IS NOT SUPPORTED AT PRESENT */
658 
659 static void link_recv_event(struct link_event *ev)
660 {
661 	ev->fcn(ev->addr, ev->name, ev->up);
662 	kfree(ev);
663 }
664 
665 static void link_send_event(void (*fcn)(u32 a, char *n, int up),
666 			    struct link *l_ptr, int up)
667 {
668 	struct link_event *ev;
669 
670 	ev = kmalloc(sizeof(*ev), GFP_ATOMIC);
671 	if (!ev) {
672 		warn("Link event allocation failure\n");
673 		return;
674 	}
675 	ev->addr = l_ptr->addr;
676 	ev->up = up;
677 	ev->fcn = fcn;
678 	memcpy(ev->name, l_ptr->name, TIPC_MAX_LINK_NAME);
679 	tipc_k_signal((Handler)link_recv_event, (unsigned long)ev);
680 }
681 
682 #else
683 
684 #define link_send_event(fcn, l_ptr, up) do { } while (0)
685 
686 #endif
687 
688 void tipc_link_reset(struct link *l_ptr)
689 {
690 	struct sk_buff *buf;
691 	u32 prev_state = l_ptr->state;
692 	u32 checkpoint = l_ptr->next_in_no;
693 	int was_active_link = tipc_link_is_active(l_ptr);
694 
695 	msg_set_session(l_ptr->pmsg, msg_session(l_ptr->pmsg) + 1);
696 
697         /* Link is down, accept any session: */
698 	l_ptr->peer_session = 0;
699 
700         /* Prepare for max packet size negotiation */
701 	link_init_max_pkt(l_ptr);
702 
703 	l_ptr->state = RESET_UNKNOWN;
704 	dbg_link_state("Resetting Link\n");
705 
706 	if ((prev_state == RESET_UNKNOWN) || (prev_state == RESET_RESET))
707 		return;
708 
709 	tipc_node_link_down(l_ptr->owner, l_ptr);
710 	tipc_bearer_remove_dest(l_ptr->b_ptr, l_ptr->addr);
711 #if 0
712 	tipc_printf(TIPC_CONS, "\nReset link <%s>\n", l_ptr->name);
713 	dbg_link_dump();
714 #endif
715 	if (was_active_link && tipc_node_has_active_links(l_ptr->owner) &&
716 	    l_ptr->owner->permit_changeover) {
717 		l_ptr->reset_checkpoint = checkpoint;
718 		l_ptr->exp_msg_count = START_CHANGEOVER;
719 	}
720 
721 	/* Clean up all queues: */
722 
723 	link_release_outqueue(l_ptr);
724 	buf_discard(l_ptr->proto_msg_queue);
725 	l_ptr->proto_msg_queue = NULL;
726 	buf = l_ptr->oldest_deferred_in;
727 	while (buf) {
728 		struct sk_buff *next = buf->next;
729 		buf_discard(buf);
730 		buf = next;
731 	}
732 	if (!list_empty(&l_ptr->waiting_ports))
733 		tipc_link_wakeup_ports(l_ptr, 1);
734 
735 	l_ptr->retransm_queue_head = 0;
736 	l_ptr->retransm_queue_size = 0;
737 	l_ptr->last_out = NULL;
738 	l_ptr->first_out = NULL;
739 	l_ptr->next_out = NULL;
740 	l_ptr->unacked_window = 0;
741 	l_ptr->checkpoint = 1;
742 	l_ptr->next_out_no = 1;
743 	l_ptr->deferred_inqueue_sz = 0;
744 	l_ptr->oldest_deferred_in = NULL;
745 	l_ptr->newest_deferred_in = NULL;
746 	l_ptr->fsm_msg_cnt = 0;
747 	l_ptr->stale_count = 0;
748 	link_reset_statistics(l_ptr);
749 
750 	link_send_event(tipc_cfg_link_event, l_ptr, 0);
751 	if (!in_own_cluster(l_ptr->addr))
752 		link_send_event(tipc_disc_link_event, l_ptr, 0);
753 }
754 
755 
756 static void link_activate(struct link *l_ptr)
757 {
758 	l_ptr->next_in_no = l_ptr->stats.recv_info = 1;
759 	tipc_node_link_up(l_ptr->owner, l_ptr);
760 	tipc_bearer_add_dest(l_ptr->b_ptr, l_ptr->addr);
761 	link_send_event(tipc_cfg_link_event, l_ptr, 1);
762 	if (!in_own_cluster(l_ptr->addr))
763 		link_send_event(tipc_disc_link_event, l_ptr, 1);
764 }
765 
766 /**
767  * link_state_event - link finite state machine
768  * @l_ptr: pointer to link
769  * @event: state machine event to process
770  */
771 
772 static void link_state_event(struct link *l_ptr, unsigned event)
773 {
774 	struct link *other;
775 	u32 cont_intv = l_ptr->continuity_interval;
776 
777 	if (!l_ptr->started && (event != STARTING_EVT))
778 		return;		/* Not yet. */
779 
780 	if (link_blocked(l_ptr)) {
781 		if (event == TIMEOUT_EVT) {
782 			link_set_timer(l_ptr, cont_intv);
783 		}
784 		return;	  /* Changeover going on */
785 	}
786 	dbg_link("STATE_EV: <%s> ", l_ptr->name);
787 
788 	switch (l_ptr->state) {
789 	case WORKING_WORKING:
790 		dbg_link("WW/");
791 		switch (event) {
792 		case TRAFFIC_MSG_EVT:
793 			dbg_link("TRF-");
794 			/* fall through */
795 		case ACTIVATE_MSG:
796 			dbg_link("ACT\n");
797 			break;
798 		case TIMEOUT_EVT:
799 			dbg_link("TIM ");
800 			if (l_ptr->next_in_no != l_ptr->checkpoint) {
801 				l_ptr->checkpoint = l_ptr->next_in_no;
802 				if (tipc_bclink_acks_missing(l_ptr->owner)) {
803 					tipc_link_send_proto_msg(l_ptr, STATE_MSG,
804 								 0, 0, 0, 0, 0);
805 					l_ptr->fsm_msg_cnt++;
806 				} else if (l_ptr->max_pkt < l_ptr->max_pkt_target) {
807 					tipc_link_send_proto_msg(l_ptr, STATE_MSG,
808 								 1, 0, 0, 0, 0);
809 					l_ptr->fsm_msg_cnt++;
810 				}
811 				link_set_timer(l_ptr, cont_intv);
812 				break;
813 			}
814 			dbg_link(" -> WU\n");
815 			l_ptr->state = WORKING_UNKNOWN;
816 			l_ptr->fsm_msg_cnt = 0;
817 			tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
818 			l_ptr->fsm_msg_cnt++;
819 			link_set_timer(l_ptr, cont_intv / 4);
820 			break;
821 		case RESET_MSG:
822 			dbg_link("RES -> RR\n");
823 			info("Resetting link <%s>, requested by peer\n",
824 			     l_ptr->name);
825 			tipc_link_reset(l_ptr);
826 			l_ptr->state = RESET_RESET;
827 			l_ptr->fsm_msg_cnt = 0;
828 			tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
829 			l_ptr->fsm_msg_cnt++;
830 			link_set_timer(l_ptr, cont_intv);
831 			break;
832 		default:
833 			err("Unknown link event %u in WW state\n", event);
834 		}
835 		break;
836 	case WORKING_UNKNOWN:
837 		dbg_link("WU/");
838 		switch (event) {
839 		case TRAFFIC_MSG_EVT:
840 			dbg_link("TRF-");
841 		case ACTIVATE_MSG:
842 			dbg_link("ACT -> WW\n");
843 			l_ptr->state = WORKING_WORKING;
844 			l_ptr->fsm_msg_cnt = 0;
845 			link_set_timer(l_ptr, cont_intv);
846 			break;
847 		case RESET_MSG:
848 			dbg_link("RES -> RR\n");
849 			info("Resetting link <%s>, requested by peer "
850 			     "while probing\n", l_ptr->name);
851 			tipc_link_reset(l_ptr);
852 			l_ptr->state = RESET_RESET;
853 			l_ptr->fsm_msg_cnt = 0;
854 			tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
855 			l_ptr->fsm_msg_cnt++;
856 			link_set_timer(l_ptr, cont_intv);
857 			break;
858 		case TIMEOUT_EVT:
859 			dbg_link("TIM ");
860 			if (l_ptr->next_in_no != l_ptr->checkpoint) {
861 				dbg_link("-> WW \n");
862 				l_ptr->state = WORKING_WORKING;
863 				l_ptr->fsm_msg_cnt = 0;
864 				l_ptr->checkpoint = l_ptr->next_in_no;
865 				if (tipc_bclink_acks_missing(l_ptr->owner)) {
866 					tipc_link_send_proto_msg(l_ptr, STATE_MSG,
867 								 0, 0, 0, 0, 0);
868 					l_ptr->fsm_msg_cnt++;
869 				}
870 				link_set_timer(l_ptr, cont_intv);
871 			} else if (l_ptr->fsm_msg_cnt < l_ptr->abort_limit) {
872 				dbg_link("Probing %u/%u,timer = %u ms)\n",
873 					 l_ptr->fsm_msg_cnt, l_ptr->abort_limit,
874 					 cont_intv / 4);
875 				tipc_link_send_proto_msg(l_ptr, STATE_MSG,
876 							 1, 0, 0, 0, 0);
877 				l_ptr->fsm_msg_cnt++;
878 				link_set_timer(l_ptr, cont_intv / 4);
879 			} else {	/* Link has failed */
880 				dbg_link("-> RU (%u probes unanswered)\n",
881 					 l_ptr->fsm_msg_cnt);
882 				warn("Resetting link <%s>, peer not responding\n",
883 				     l_ptr->name);
884 				tipc_link_reset(l_ptr);
885 				l_ptr->state = RESET_UNKNOWN;
886 				l_ptr->fsm_msg_cnt = 0;
887 				tipc_link_send_proto_msg(l_ptr, RESET_MSG,
888 							 0, 0, 0, 0, 0);
889 				l_ptr->fsm_msg_cnt++;
890 				link_set_timer(l_ptr, cont_intv);
891 			}
892 			break;
893 		default:
894 			err("Unknown link event %u in WU state\n", event);
895 		}
896 		break;
897 	case RESET_UNKNOWN:
898 		dbg_link("RU/");
899 		switch (event) {
900 		case TRAFFIC_MSG_EVT:
901 			dbg_link("TRF-\n");
902 			break;
903 		case ACTIVATE_MSG:
904 			other = l_ptr->owner->active_links[0];
905 			if (other && link_working_unknown(other)) {
906 				dbg_link("ACT\n");
907 				break;
908 			}
909 			dbg_link("ACT -> WW\n");
910 			l_ptr->state = WORKING_WORKING;
911 			l_ptr->fsm_msg_cnt = 0;
912 			link_activate(l_ptr);
913 			tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
914 			l_ptr->fsm_msg_cnt++;
915 			link_set_timer(l_ptr, cont_intv);
916 			break;
917 		case RESET_MSG:
918 			dbg_link("RES \n");
919 			dbg_link(" -> RR\n");
920 			l_ptr->state = RESET_RESET;
921 			l_ptr->fsm_msg_cnt = 0;
922 			tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 1, 0, 0, 0, 0);
923 			l_ptr->fsm_msg_cnt++;
924 			link_set_timer(l_ptr, cont_intv);
925 			break;
926 		case STARTING_EVT:
927 			dbg_link("START-");
928 			l_ptr->started = 1;
929 			/* fall through */
930 		case TIMEOUT_EVT:
931 			dbg_link("TIM \n");
932 			tipc_link_send_proto_msg(l_ptr, RESET_MSG, 0, 0, 0, 0, 0);
933 			l_ptr->fsm_msg_cnt++;
934 			link_set_timer(l_ptr, cont_intv);
935 			break;
936 		default:
937 			err("Unknown link event %u in RU state\n", event);
938 		}
939 		break;
940 	case RESET_RESET:
941 		dbg_link("RR/ ");
942 		switch (event) {
943 		case TRAFFIC_MSG_EVT:
944 			dbg_link("TRF-");
945 			/* fall through */
946 		case ACTIVATE_MSG:
947 			other = l_ptr->owner->active_links[0];
948 			if (other && link_working_unknown(other)) {
949 				dbg_link("ACT\n");
950 				break;
951 			}
952 			dbg_link("ACT -> WW\n");
953 			l_ptr->state = WORKING_WORKING;
954 			l_ptr->fsm_msg_cnt = 0;
955 			link_activate(l_ptr);
956 			tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
957 			l_ptr->fsm_msg_cnt++;
958 			link_set_timer(l_ptr, cont_intv);
959 			break;
960 		case RESET_MSG:
961 			dbg_link("RES\n");
962 			break;
963 		case TIMEOUT_EVT:
964 			dbg_link("TIM\n");
965 			tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
966 			l_ptr->fsm_msg_cnt++;
967 			link_set_timer(l_ptr, cont_intv);
968 			dbg_link("fsm_msg_cnt %u\n", l_ptr->fsm_msg_cnt);
969 			break;
970 		default:
971 			err("Unknown link event %u in RR state\n", event);
972 		}
973 		break;
974 	default:
975 		err("Unknown link state %u/%u\n", l_ptr->state, event);
976 	}
977 }
978 
979 /*
980  * link_bundle_buf(): Append contents of a buffer to
981  * the tail of an existing one.
982  */
983 
984 static int link_bundle_buf(struct link *l_ptr,
985 			   struct sk_buff *bundler,
986 			   struct sk_buff *buf)
987 {
988 	struct tipc_msg *bundler_msg = buf_msg(bundler);
989 	struct tipc_msg *msg = buf_msg(buf);
990 	u32 size = msg_size(msg);
991 	u32 bundle_size = msg_size(bundler_msg);
992 	u32 to_pos = align(bundle_size);
993 	u32 pad = to_pos - bundle_size;
994 
995 	if (msg_user(bundler_msg) != MSG_BUNDLER)
996 		return 0;
997 	if (msg_type(bundler_msg) != OPEN_MSG)
998 		return 0;
999 	if (skb_tailroom(bundler) < (pad + size))
1000 		return 0;
1001 	if (link_max_pkt(l_ptr) < (to_pos + size))
1002 		return 0;
1003 
1004 	skb_put(bundler, pad + size);
1005 	memcpy(bundler->data + to_pos, buf->data, size);
1006 	msg_set_size(bundler_msg, to_pos + size);
1007 	msg_set_msgcnt(bundler_msg, msg_msgcnt(bundler_msg) + 1);
1008 	dbg("Packed msg # %u(%u octets) into pos %u in buf(#%u)\n",
1009 	    msg_msgcnt(bundler_msg), size, to_pos, msg_seqno(bundler_msg));
1010 	msg_dbg(msg, "PACKD:");
1011 	buf_discard(buf);
1012 	l_ptr->stats.sent_bundled++;
1013 	return 1;
1014 }
1015 
1016 static void link_add_to_outqueue(struct link *l_ptr,
1017 				 struct sk_buff *buf,
1018 				 struct tipc_msg *msg)
1019 {
1020 	u32 ack = mod(l_ptr->next_in_no - 1);
1021 	u32 seqno = mod(l_ptr->next_out_no++);
1022 
1023 	msg_set_word(msg, 2, ((ack << 16) | seqno));
1024 	msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1025 	buf->next = NULL;
1026 	if (l_ptr->first_out) {
1027 		l_ptr->last_out->next = buf;
1028 		l_ptr->last_out = buf;
1029 	} else
1030 		l_ptr->first_out = l_ptr->last_out = buf;
1031 	l_ptr->out_queue_size++;
1032 }
1033 
1034 /*
1035  * tipc_link_send_buf() is the 'full path' for messages, called from
1036  * inside TIPC when the 'fast path' in tipc_send_buf
1037  * has failed, and from link_send()
1038  */
1039 
1040 int tipc_link_send_buf(struct link *l_ptr, struct sk_buff *buf)
1041 {
1042 	struct tipc_msg *msg = buf_msg(buf);
1043 	u32 size = msg_size(msg);
1044 	u32 dsz = msg_data_sz(msg);
1045 	u32 queue_size = l_ptr->out_queue_size;
1046 	u32 imp = msg_tot_importance(msg);
1047 	u32 queue_limit = l_ptr->queue_limit[imp];
1048 	u32 max_packet = link_max_pkt(l_ptr);
1049 
1050 	msg_set_prevnode(msg, tipc_own_addr);	/* If routed message */
1051 
1052 	/* Match msg importance against queue limits: */
1053 
1054 	if (unlikely(queue_size >= queue_limit)) {
1055 		if (imp <= TIPC_CRITICAL_IMPORTANCE) {
1056 			return link_schedule_port(l_ptr, msg_origport(msg),
1057 						  size);
1058 		}
1059 		msg_dbg(msg, "TIPC: Congestion, throwing away\n");
1060 		buf_discard(buf);
1061 		if (imp > CONN_MANAGER) {
1062 			warn("Resetting link <%s>, send queue full", l_ptr->name);
1063 			tipc_link_reset(l_ptr);
1064 		}
1065 		return dsz;
1066 	}
1067 
1068 	/* Fragmentation needed ? */
1069 
1070 	if (size > max_packet)
1071 		return tipc_link_send_long_buf(l_ptr, buf);
1072 
1073 	/* Packet can be queued or sent: */
1074 
1075 	if (queue_size > l_ptr->stats.max_queue_sz)
1076 		l_ptr->stats.max_queue_sz = queue_size;
1077 
1078 	if (likely(!tipc_bearer_congested(l_ptr->b_ptr, l_ptr) &&
1079 		   !link_congested(l_ptr))) {
1080 		link_add_to_outqueue(l_ptr, buf, msg);
1081 
1082 		if (likely(tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr))) {
1083 			l_ptr->unacked_window = 0;
1084 		} else {
1085 			tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
1086 			l_ptr->stats.bearer_congs++;
1087 			l_ptr->next_out = buf;
1088 		}
1089 		return dsz;
1090 	}
1091 	/* Congestion: can message be bundled ?: */
1092 
1093 	if ((msg_user(msg) != CHANGEOVER_PROTOCOL) &&
1094 	    (msg_user(msg) != MSG_FRAGMENTER)) {
1095 
1096 		/* Try adding message to an existing bundle */
1097 
1098 		if (l_ptr->next_out &&
1099 		    link_bundle_buf(l_ptr, l_ptr->last_out, buf)) {
1100 			tipc_bearer_resolve_congestion(l_ptr->b_ptr, l_ptr);
1101 			return dsz;
1102 		}
1103 
1104 		/* Try creating a new bundle */
1105 
1106 		if (size <= max_packet * 2 / 3) {
1107 			struct sk_buff *bundler = buf_acquire(max_packet);
1108 			struct tipc_msg bundler_hdr;
1109 
1110 			if (bundler) {
1111 				msg_init(&bundler_hdr, MSG_BUNDLER, OPEN_MSG,
1112 					 TIPC_OK, INT_H_SIZE, l_ptr->addr);
1113 				memcpy(bundler->data, (unchar *)&bundler_hdr,
1114 				       INT_H_SIZE);
1115 				skb_trim(bundler, INT_H_SIZE);
1116 				link_bundle_buf(l_ptr, bundler, buf);
1117 				buf = bundler;
1118 				msg = buf_msg(buf);
1119 				l_ptr->stats.sent_bundles++;
1120 			}
1121 		}
1122 	}
1123 	if (!l_ptr->next_out)
1124 		l_ptr->next_out = buf;
1125 	link_add_to_outqueue(l_ptr, buf, msg);
1126 	tipc_bearer_resolve_congestion(l_ptr->b_ptr, l_ptr);
1127 	return dsz;
1128 }
1129 
1130 /*
1131  * tipc_link_send(): same as tipc_link_send_buf(), but the link to use has
1132  * not been selected yet, and the the owner node is not locked
1133  * Called by TIPC internal users, e.g. the name distributor
1134  */
1135 
1136 int tipc_link_send(struct sk_buff *buf, u32 dest, u32 selector)
1137 {
1138 	struct link *l_ptr;
1139 	struct node *n_ptr;
1140 	int res = -ELINKCONG;
1141 
1142 	read_lock_bh(&tipc_net_lock);
1143 	n_ptr = tipc_node_select(dest, selector);
1144 	if (n_ptr) {
1145 		tipc_node_lock(n_ptr);
1146 		l_ptr = n_ptr->active_links[selector & 1];
1147 		if (l_ptr) {
1148 			dbg("tipc_link_send: found link %x for dest %x\n", l_ptr, dest);
1149 			res = tipc_link_send_buf(l_ptr, buf);
1150 		} else {
1151 			dbg("Attempt to send msg to unreachable node:\n");
1152 			msg_dbg(buf_msg(buf),">>>");
1153 			buf_discard(buf);
1154 		}
1155 		tipc_node_unlock(n_ptr);
1156 	} else {
1157 		dbg("Attempt to send msg to unknown node:\n");
1158 		msg_dbg(buf_msg(buf),">>>");
1159 		buf_discard(buf);
1160 	}
1161 	read_unlock_bh(&tipc_net_lock);
1162 	return res;
1163 }
1164 
1165 /*
1166  * link_send_buf_fast: Entry for data messages where the
1167  * destination link is known and the header is complete,
1168  * inclusive total message length. Very time critical.
1169  * Link is locked. Returns user data length.
1170  */
1171 
1172 static int link_send_buf_fast(struct link *l_ptr, struct sk_buff *buf,
1173 			      u32 *used_max_pkt)
1174 {
1175 	struct tipc_msg *msg = buf_msg(buf);
1176 	int res = msg_data_sz(msg);
1177 
1178 	if (likely(!link_congested(l_ptr))) {
1179 		if (likely(msg_size(msg) <= link_max_pkt(l_ptr))) {
1180 			if (likely(list_empty(&l_ptr->b_ptr->cong_links))) {
1181 				link_add_to_outqueue(l_ptr, buf, msg);
1182 				if (likely(tipc_bearer_send(l_ptr->b_ptr, buf,
1183 							    &l_ptr->media_addr))) {
1184 					l_ptr->unacked_window = 0;
1185 					msg_dbg(msg,"SENT_FAST:");
1186 					return res;
1187 				}
1188 				dbg("failed sent fast...\n");
1189 				tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
1190 				l_ptr->stats.bearer_congs++;
1191 				l_ptr->next_out = buf;
1192 				return res;
1193 			}
1194 		}
1195 		else
1196 			*used_max_pkt = link_max_pkt(l_ptr);
1197 	}
1198 	return tipc_link_send_buf(l_ptr, buf);  /* All other cases */
1199 }
1200 
1201 /*
1202  * tipc_send_buf_fast: Entry for data messages where the
1203  * destination node is known and the header is complete,
1204  * inclusive total message length.
1205  * Returns user data length.
1206  */
1207 int tipc_send_buf_fast(struct sk_buff *buf, u32 destnode)
1208 {
1209 	struct link *l_ptr;
1210 	struct node *n_ptr;
1211 	int res;
1212 	u32 selector = msg_origport(buf_msg(buf)) & 1;
1213 	u32 dummy;
1214 
1215 	if (destnode == tipc_own_addr)
1216 		return tipc_port_recv_msg(buf);
1217 
1218 	read_lock_bh(&tipc_net_lock);
1219 	n_ptr = tipc_node_select(destnode, selector);
1220 	if (likely(n_ptr)) {
1221 		tipc_node_lock(n_ptr);
1222 		l_ptr = n_ptr->active_links[selector];
1223 		dbg("send_fast: buf %x selected %x, destnode = %x\n",
1224 		    buf, l_ptr, destnode);
1225 		if (likely(l_ptr)) {
1226 			res = link_send_buf_fast(l_ptr, buf, &dummy);
1227 			tipc_node_unlock(n_ptr);
1228 			read_unlock_bh(&tipc_net_lock);
1229 			return res;
1230 		}
1231 		tipc_node_unlock(n_ptr);
1232 	}
1233 	read_unlock_bh(&tipc_net_lock);
1234 	res = msg_data_sz(buf_msg(buf));
1235 	tipc_reject_msg(buf, TIPC_ERR_NO_NODE);
1236 	return res;
1237 }
1238 
1239 
1240 /*
1241  * tipc_link_send_sections_fast: Entry for messages where the
1242  * destination processor is known and the header is complete,
1243  * except for total message length.
1244  * Returns user data length or errno.
1245  */
1246 int tipc_link_send_sections_fast(struct port *sender,
1247 				 struct iovec const *msg_sect,
1248 				 const u32 num_sect,
1249 				 u32 destaddr)
1250 {
1251 	struct tipc_msg *hdr = &sender->publ.phdr;
1252 	struct link *l_ptr;
1253 	struct sk_buff *buf;
1254 	struct node *node;
1255 	int res;
1256 	u32 selector = msg_origport(hdr) & 1;
1257 
1258 again:
1259 	/*
1260 	 * Try building message using port's max_pkt hint.
1261 	 * (Must not hold any locks while building message.)
1262 	 */
1263 
1264 	res = msg_build(hdr, msg_sect, num_sect, sender->max_pkt,
1265 			!sender->user_port, &buf);
1266 
1267 	read_lock_bh(&tipc_net_lock);
1268 	node = tipc_node_select(destaddr, selector);
1269 	if (likely(node)) {
1270 		tipc_node_lock(node);
1271 		l_ptr = node->active_links[selector];
1272 		if (likely(l_ptr)) {
1273 			if (likely(buf)) {
1274 				res = link_send_buf_fast(l_ptr, buf,
1275 							 &sender->max_pkt);
1276 				if (unlikely(res < 0))
1277 					buf_discard(buf);
1278 exit:
1279 				tipc_node_unlock(node);
1280 				read_unlock_bh(&tipc_net_lock);
1281 				return res;
1282 			}
1283 
1284 			/* Exit if build request was invalid */
1285 
1286 			if (unlikely(res < 0))
1287 				goto exit;
1288 
1289 			/* Exit if link (or bearer) is congested */
1290 
1291 			if (link_congested(l_ptr) ||
1292 			    !list_empty(&l_ptr->b_ptr->cong_links)) {
1293 				res = link_schedule_port(l_ptr,
1294 							 sender->publ.ref, res);
1295 				goto exit;
1296 			}
1297 
1298 			/*
1299 			 * Message size exceeds max_pkt hint; update hint,
1300 			 * then re-try fast path or fragment the message
1301 			 */
1302 
1303 			sender->max_pkt = link_max_pkt(l_ptr);
1304 			tipc_node_unlock(node);
1305 			read_unlock_bh(&tipc_net_lock);
1306 
1307 
1308 			if ((msg_hdr_sz(hdr) + res) <= sender->max_pkt)
1309 				goto again;
1310 
1311 			return link_send_sections_long(sender, msg_sect,
1312 						       num_sect, destaddr);
1313 		}
1314 		tipc_node_unlock(node);
1315 	}
1316 	read_unlock_bh(&tipc_net_lock);
1317 
1318 	/* Couldn't find a link to the destination node */
1319 
1320 	if (buf)
1321 		return tipc_reject_msg(buf, TIPC_ERR_NO_NODE);
1322 	if (res >= 0)
1323 		return tipc_port_reject_sections(sender, hdr, msg_sect, num_sect,
1324 						 TIPC_ERR_NO_NODE);
1325 	return res;
1326 }
1327 
1328 /*
1329  * link_send_sections_long(): Entry for long messages where the
1330  * destination node is known and the header is complete,
1331  * inclusive total message length.
1332  * Link and bearer congestion status have been checked to be ok,
1333  * and are ignored if they change.
1334  *
1335  * Note that fragments do not use the full link MTU so that they won't have
1336  * to undergo refragmentation if link changeover causes them to be sent
1337  * over another link with an additional tunnel header added as prefix.
1338  * (Refragmentation will still occur if the other link has a smaller MTU.)
1339  *
1340  * Returns user data length or errno.
1341  */
1342 static int link_send_sections_long(struct port *sender,
1343 				   struct iovec const *msg_sect,
1344 				   u32 num_sect,
1345 				   u32 destaddr)
1346 {
1347 	struct link *l_ptr;
1348 	struct node *node;
1349 	struct tipc_msg *hdr = &sender->publ.phdr;
1350 	u32 dsz = msg_data_sz(hdr);
1351 	u32 max_pkt,fragm_sz,rest;
1352 	struct tipc_msg fragm_hdr;
1353 	struct sk_buff *buf,*buf_chain,*prev;
1354 	u32 fragm_crs,fragm_rest,hsz,sect_rest;
1355 	const unchar *sect_crs;
1356 	int curr_sect;
1357 	u32 fragm_no;
1358 
1359 again:
1360 	fragm_no = 1;
1361 	max_pkt = sender->max_pkt - INT_H_SIZE;
1362 		/* leave room for tunnel header in case of link changeover */
1363 	fragm_sz = max_pkt - INT_H_SIZE;
1364 		/* leave room for fragmentation header in each fragment */
1365 	rest = dsz;
1366 	fragm_crs = 0;
1367 	fragm_rest = 0;
1368 	sect_rest = 0;
1369 	sect_crs = NULL;
1370 	curr_sect = -1;
1371 
1372 	/* Prepare reusable fragment header: */
1373 
1374 	msg_dbg(hdr, ">FRAGMENTING>");
1375 	msg_init(&fragm_hdr, MSG_FRAGMENTER, FIRST_FRAGMENT,
1376 		 TIPC_OK, INT_H_SIZE, msg_destnode(hdr));
1377 	msg_set_link_selector(&fragm_hdr, sender->publ.ref);
1378 	msg_set_size(&fragm_hdr, max_pkt);
1379 	msg_set_fragm_no(&fragm_hdr, 1);
1380 
1381 	/* Prepare header of first fragment: */
1382 
1383 	buf_chain = buf = buf_acquire(max_pkt);
1384 	if (!buf)
1385 		return -ENOMEM;
1386 	buf->next = NULL;
1387 	memcpy(buf->data, (unchar *)&fragm_hdr, INT_H_SIZE);
1388 	hsz = msg_hdr_sz(hdr);
1389 	memcpy(buf->data + INT_H_SIZE, (unchar *)hdr, hsz);
1390 	msg_dbg(buf_msg(buf), ">BUILD>");
1391 
1392 	/* Chop up message: */
1393 
1394 	fragm_crs = INT_H_SIZE + hsz;
1395 	fragm_rest = fragm_sz - hsz;
1396 
1397 	do {		/* For all sections */
1398 		u32 sz;
1399 
1400 		if (!sect_rest) {
1401 			sect_rest = msg_sect[++curr_sect].iov_len;
1402 			sect_crs = (const unchar *)msg_sect[curr_sect].iov_base;
1403 		}
1404 
1405 		if (sect_rest < fragm_rest)
1406 			sz = sect_rest;
1407 		else
1408 			sz = fragm_rest;
1409 
1410 		if (likely(!sender->user_port)) {
1411 			if (copy_from_user(buf->data + fragm_crs, sect_crs, sz)) {
1412 error:
1413 				for (; buf_chain; buf_chain = buf) {
1414 					buf = buf_chain->next;
1415 					buf_discard(buf_chain);
1416 				}
1417 				return -EFAULT;
1418 			}
1419 		} else
1420 			memcpy(buf->data + fragm_crs, sect_crs, sz);
1421 
1422 		sect_crs += sz;
1423 		sect_rest -= sz;
1424 		fragm_crs += sz;
1425 		fragm_rest -= sz;
1426 		rest -= sz;
1427 
1428 		if (!fragm_rest && rest) {
1429 
1430 			/* Initiate new fragment: */
1431 			if (rest <= fragm_sz) {
1432 				fragm_sz = rest;
1433 				msg_set_type(&fragm_hdr,LAST_FRAGMENT);
1434 			} else {
1435 				msg_set_type(&fragm_hdr, FRAGMENT);
1436 			}
1437 			msg_set_size(&fragm_hdr, fragm_sz + INT_H_SIZE);
1438 			msg_set_fragm_no(&fragm_hdr, ++fragm_no);
1439 			prev = buf;
1440 			buf = buf_acquire(fragm_sz + INT_H_SIZE);
1441 			if (!buf)
1442 				goto error;
1443 
1444 			buf->next = NULL;
1445 			prev->next = buf;
1446 			memcpy(buf->data, (unchar *)&fragm_hdr, INT_H_SIZE);
1447 			fragm_crs = INT_H_SIZE;
1448 			fragm_rest = fragm_sz;
1449 			msg_dbg(buf_msg(buf),"  >BUILD>");
1450 		}
1451 	}
1452 	while (rest > 0);
1453 
1454 	/*
1455 	 * Now we have a buffer chain. Select a link and check
1456 	 * that packet size is still OK
1457 	 */
1458 	node = tipc_node_select(destaddr, sender->publ.ref & 1);
1459 	if (likely(node)) {
1460 		tipc_node_lock(node);
1461 		l_ptr = node->active_links[sender->publ.ref & 1];
1462 		if (!l_ptr) {
1463 			tipc_node_unlock(node);
1464 			goto reject;
1465 		}
1466 		if (link_max_pkt(l_ptr) < max_pkt) {
1467 			sender->max_pkt = link_max_pkt(l_ptr);
1468 			tipc_node_unlock(node);
1469 			for (; buf_chain; buf_chain = buf) {
1470 				buf = buf_chain->next;
1471 				buf_discard(buf_chain);
1472 			}
1473 			goto again;
1474 		}
1475 	} else {
1476 reject:
1477 		for (; buf_chain; buf_chain = buf) {
1478 			buf = buf_chain->next;
1479 			buf_discard(buf_chain);
1480 		}
1481 		return tipc_port_reject_sections(sender, hdr, msg_sect, num_sect,
1482 						 TIPC_ERR_NO_NODE);
1483 	}
1484 
1485 	/* Append whole chain to send queue: */
1486 
1487 	buf = buf_chain;
1488 	l_ptr->long_msg_seq_no = mod(l_ptr->long_msg_seq_no + 1);
1489 	if (!l_ptr->next_out)
1490 		l_ptr->next_out = buf_chain;
1491 	l_ptr->stats.sent_fragmented++;
1492 	while (buf) {
1493 		struct sk_buff *next = buf->next;
1494 		struct tipc_msg *msg = buf_msg(buf);
1495 
1496 		l_ptr->stats.sent_fragments++;
1497 		msg_set_long_msgno(msg, l_ptr->long_msg_seq_no);
1498 		link_add_to_outqueue(l_ptr, buf, msg);
1499 		msg_dbg(msg, ">ADD>");
1500 		buf = next;
1501 	}
1502 
1503 	/* Send it, if possible: */
1504 
1505 	tipc_link_push_queue(l_ptr);
1506 	tipc_node_unlock(node);
1507 	return dsz;
1508 }
1509 
1510 /*
1511  * tipc_link_push_packet: Push one unsent packet to the media
1512  */
1513 u32 tipc_link_push_packet(struct link *l_ptr)
1514 {
1515 	struct sk_buff *buf = l_ptr->first_out;
1516 	u32 r_q_size = l_ptr->retransm_queue_size;
1517 	u32 r_q_head = l_ptr->retransm_queue_head;
1518 
1519 	/* Step to position where retransmission failed, if any,    */
1520 	/* consider that buffers may have been released in meantime */
1521 
1522 	if (r_q_size && buf) {
1523 		u32 last = lesser(mod(r_q_head + r_q_size),
1524 				  link_last_sent(l_ptr));
1525 		u32 first = msg_seqno(buf_msg(buf));
1526 
1527 		while (buf && less(first, r_q_head)) {
1528 			first = mod(first + 1);
1529 			buf = buf->next;
1530 		}
1531 		l_ptr->retransm_queue_head = r_q_head = first;
1532 		l_ptr->retransm_queue_size = r_q_size = mod(last - first);
1533 	}
1534 
1535 	/* Continue retransmission now, if there is anything: */
1536 
1537 	if (r_q_size && buf && !skb_cloned(buf)) {
1538 		msg_set_ack(buf_msg(buf), mod(l_ptr->next_in_no - 1));
1539 		msg_set_bcast_ack(buf_msg(buf), l_ptr->owner->bclink.last_in);
1540 		if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1541 			msg_dbg(buf_msg(buf), ">DEF-RETR>");
1542 			l_ptr->retransm_queue_head = mod(++r_q_head);
1543 			l_ptr->retransm_queue_size = --r_q_size;
1544 			l_ptr->stats.retransmitted++;
1545 			return TIPC_OK;
1546 		} else {
1547 			l_ptr->stats.bearer_congs++;
1548 			msg_dbg(buf_msg(buf), "|>DEF-RETR>");
1549 			return PUSH_FAILED;
1550 		}
1551 	}
1552 
1553 	/* Send deferred protocol message, if any: */
1554 
1555 	buf = l_ptr->proto_msg_queue;
1556 	if (buf) {
1557 		msg_set_ack(buf_msg(buf), mod(l_ptr->next_in_no - 1));
1558 		msg_set_bcast_ack(buf_msg(buf),l_ptr->owner->bclink.last_in);
1559 		if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1560 			msg_dbg(buf_msg(buf), ">DEF-PROT>");
1561 			l_ptr->unacked_window = 0;
1562 			buf_discard(buf);
1563 			l_ptr->proto_msg_queue = NULL;
1564 			return TIPC_OK;
1565 		} else {
1566 			msg_dbg(buf_msg(buf), "|>DEF-PROT>");
1567 			l_ptr->stats.bearer_congs++;
1568 			return PUSH_FAILED;
1569 		}
1570 	}
1571 
1572 	/* Send one deferred data message, if send window not full: */
1573 
1574 	buf = l_ptr->next_out;
1575 	if (buf) {
1576 		struct tipc_msg *msg = buf_msg(buf);
1577 		u32 next = msg_seqno(msg);
1578 		u32 first = msg_seqno(buf_msg(l_ptr->first_out));
1579 
1580 		if (mod(next - first) < l_ptr->queue_limit[0]) {
1581 			msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1582 			msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1583 			if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1584 				if (msg_user(msg) == MSG_BUNDLER)
1585 					msg_set_type(msg, CLOSED_MSG);
1586 				msg_dbg(msg, ">PUSH-DATA>");
1587 				l_ptr->next_out = buf->next;
1588 				return TIPC_OK;
1589 			} else {
1590 				msg_dbg(msg, "|PUSH-DATA|");
1591 				l_ptr->stats.bearer_congs++;
1592 				return PUSH_FAILED;
1593 			}
1594 		}
1595 	}
1596 	return PUSH_FINISHED;
1597 }
1598 
1599 /*
1600  * push_queue(): push out the unsent messages of a link where
1601  *               congestion has abated. Node is locked
1602  */
1603 void tipc_link_push_queue(struct link *l_ptr)
1604 {
1605 	u32 res;
1606 
1607 	if (tipc_bearer_congested(l_ptr->b_ptr, l_ptr))
1608 		return;
1609 
1610 	do {
1611 		res = tipc_link_push_packet(l_ptr);
1612 	}
1613 	while (res == TIPC_OK);
1614 	if (res == PUSH_FAILED)
1615 		tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
1616 }
1617 
1618 static void link_reset_all(unsigned long addr)
1619 {
1620 	struct node *n_ptr;
1621 	char addr_string[16];
1622 	u32 i;
1623 
1624 	read_lock_bh(&tipc_net_lock);
1625 	n_ptr = tipc_node_find((u32)addr);
1626 	if (!n_ptr) {
1627 		read_unlock_bh(&tipc_net_lock);
1628 		return;	/* node no longer exists */
1629 	}
1630 
1631 	tipc_node_lock(n_ptr);
1632 
1633 	warn("Resetting all links to %s\n",
1634 	     addr_string_fill(addr_string, n_ptr->addr));
1635 
1636 	for (i = 0; i < MAX_BEARERS; i++) {
1637 		if (n_ptr->links[i]) {
1638 			link_print(n_ptr->links[i], TIPC_OUTPUT,
1639 				   "Resetting link\n");
1640 			tipc_link_reset(n_ptr->links[i]);
1641 		}
1642 	}
1643 
1644 	tipc_node_unlock(n_ptr);
1645 	read_unlock_bh(&tipc_net_lock);
1646 }
1647 
1648 static void link_retransmit_failure(struct link *l_ptr, struct sk_buff *buf)
1649 {
1650 	struct tipc_msg *msg = buf_msg(buf);
1651 
1652 	warn("Retransmission failure on link <%s>\n", l_ptr->name);
1653 	tipc_msg_print(TIPC_OUTPUT, msg, ">RETR-FAIL>");
1654 
1655 	if (l_ptr->addr) {
1656 
1657 		/* Handle failure on standard link */
1658 
1659 		link_print(l_ptr, TIPC_OUTPUT, "Resetting link\n");
1660 		tipc_link_reset(l_ptr);
1661 
1662 	} else {
1663 
1664 		/* Handle failure on broadcast link */
1665 
1666 		struct node *n_ptr;
1667 		char addr_string[16];
1668 
1669 		tipc_printf(TIPC_OUTPUT, "Msg seq number: %u,  ", msg_seqno(msg));
1670 		tipc_printf(TIPC_OUTPUT, "Outstanding acks: %u\n", (u32)TIPC_SKB_CB(buf)->handle);
1671 
1672 		n_ptr = l_ptr->owner->next;
1673 		tipc_node_lock(n_ptr);
1674 
1675 		addr_string_fill(addr_string, n_ptr->addr);
1676 		tipc_printf(TIPC_OUTPUT, "Multicast link info for %s\n", addr_string);
1677 		tipc_printf(TIPC_OUTPUT, "Supported: %d,  ", n_ptr->bclink.supported);
1678 		tipc_printf(TIPC_OUTPUT, "Acked: %u\n", n_ptr->bclink.acked);
1679 		tipc_printf(TIPC_OUTPUT, "Last in: %u,  ", n_ptr->bclink.last_in);
1680 		tipc_printf(TIPC_OUTPUT, "Gap after: %u,  ", n_ptr->bclink.gap_after);
1681 		tipc_printf(TIPC_OUTPUT, "Gap to: %u\n", n_ptr->bclink.gap_to);
1682 		tipc_printf(TIPC_OUTPUT, "Nack sync: %u\n\n", n_ptr->bclink.nack_sync);
1683 
1684 		tipc_k_signal((Handler)link_reset_all, (unsigned long)n_ptr->addr);
1685 
1686 		tipc_node_unlock(n_ptr);
1687 
1688 		l_ptr->stale_count = 0;
1689 	}
1690 }
1691 
1692 void tipc_link_retransmit(struct link *l_ptr, struct sk_buff *buf,
1693 			  u32 retransmits)
1694 {
1695 	struct tipc_msg *msg;
1696 
1697 	if (!buf)
1698 		return;
1699 
1700 	msg = buf_msg(buf);
1701 
1702 	dbg("Retransmitting %u in link %x\n", retransmits, l_ptr);
1703 
1704 	if (tipc_bearer_congested(l_ptr->b_ptr, l_ptr)) {
1705 		if (!skb_cloned(buf)) {
1706 			msg_dbg(msg, ">NO_RETR->BCONG>");
1707 			dbg_print_link(l_ptr, "   ");
1708 			l_ptr->retransm_queue_head = msg_seqno(msg);
1709 			l_ptr->retransm_queue_size = retransmits;
1710 			return;
1711 		} else {
1712 			/* Don't retransmit if driver already has the buffer */
1713 		}
1714 	} else {
1715 		/* Detect repeated retransmit failures on uncongested bearer */
1716 
1717 		if (l_ptr->last_retransmitted == msg_seqno(msg)) {
1718 			if (++l_ptr->stale_count > 100) {
1719 				link_retransmit_failure(l_ptr, buf);
1720 				return;
1721 			}
1722 		} else {
1723 			l_ptr->last_retransmitted = msg_seqno(msg);
1724 			l_ptr->stale_count = 1;
1725 		}
1726 	}
1727 
1728 	while (retransmits && (buf != l_ptr->next_out) && buf && !skb_cloned(buf)) {
1729 		msg = buf_msg(buf);
1730 		msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1731 		msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1732 		if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1733 			msg_dbg(buf_msg(buf), ">RETR>");
1734 			buf = buf->next;
1735 			retransmits--;
1736 			l_ptr->stats.retransmitted++;
1737 		} else {
1738 			tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
1739 			l_ptr->stats.bearer_congs++;
1740 			l_ptr->retransm_queue_head = msg_seqno(buf_msg(buf));
1741 			l_ptr->retransm_queue_size = retransmits;
1742 			return;
1743 		}
1744 	}
1745 
1746 	l_ptr->retransm_queue_head = l_ptr->retransm_queue_size = 0;
1747 }
1748 
1749 /*
1750  * link_recv_non_seq: Receive packets which are outside
1751  *                    the link sequence flow
1752  */
1753 
1754 static void link_recv_non_seq(struct sk_buff *buf)
1755 {
1756 	struct tipc_msg *msg = buf_msg(buf);
1757 
1758 	if (msg_user(msg) ==  LINK_CONFIG)
1759 		tipc_disc_recv_msg(buf);
1760 	else
1761 		tipc_bclink_recv_pkt(buf);
1762 }
1763 
1764 /**
1765  * link_insert_deferred_queue - insert deferred messages back into receive chain
1766  */
1767 
1768 static struct sk_buff *link_insert_deferred_queue(struct link *l_ptr,
1769 						  struct sk_buff *buf)
1770 {
1771 	u32 seq_no;
1772 
1773 	if (l_ptr->oldest_deferred_in == NULL)
1774 		return buf;
1775 
1776 	seq_no = msg_seqno(buf_msg(l_ptr->oldest_deferred_in));
1777 	if (seq_no == mod(l_ptr->next_in_no)) {
1778 		l_ptr->newest_deferred_in->next = buf;
1779 		buf = l_ptr->oldest_deferred_in;
1780 		l_ptr->oldest_deferred_in = NULL;
1781 		l_ptr->deferred_inqueue_sz = 0;
1782 	}
1783 	return buf;
1784 }
1785 
1786 void tipc_recv_msg(struct sk_buff *head, struct tipc_bearer *tb_ptr)
1787 {
1788 	read_lock_bh(&tipc_net_lock);
1789 	while (head) {
1790 		struct bearer *b_ptr;
1791 		struct node *n_ptr;
1792 		struct link *l_ptr;
1793 		struct sk_buff *crs;
1794 		struct sk_buff *buf = head;
1795 		struct tipc_msg *msg = buf_msg(buf);
1796 		u32 seq_no = msg_seqno(msg);
1797 		u32 ackd = msg_ack(msg);
1798 		u32 released = 0;
1799 		int type;
1800 
1801 		b_ptr = (struct bearer *)tb_ptr;
1802 		TIPC_SKB_CB(buf)->handle = b_ptr;
1803 
1804 		head = head->next;
1805 		if (unlikely(msg_version(msg) != TIPC_VERSION))
1806 			goto cont;
1807 #if 0
1808 		if (msg_user(msg) != LINK_PROTOCOL)
1809 #endif
1810 			msg_dbg(msg,"<REC<");
1811 
1812 		if (unlikely(msg_non_seq(msg))) {
1813 			link_recv_non_seq(buf);
1814 			continue;
1815 		}
1816 
1817 		if (unlikely(!msg_short(msg) &&
1818 			     (msg_destnode(msg) != tipc_own_addr)))
1819 			goto cont;
1820 
1821 		n_ptr = tipc_node_find(msg_prevnode(msg));
1822 		if (unlikely(!n_ptr))
1823 			goto cont;
1824 
1825 		tipc_node_lock(n_ptr);
1826 		l_ptr = n_ptr->links[b_ptr->identity];
1827 		if (unlikely(!l_ptr)) {
1828 			tipc_node_unlock(n_ptr);
1829 			goto cont;
1830 		}
1831 		/*
1832 		 * Release acked messages
1833 		 */
1834 		if (less(n_ptr->bclink.acked, msg_bcast_ack(msg))) {
1835 			if (tipc_node_is_up(n_ptr) && n_ptr->bclink.supported)
1836 				tipc_bclink_acknowledge(n_ptr, msg_bcast_ack(msg));
1837 		}
1838 
1839 		crs = l_ptr->first_out;
1840 		while ((crs != l_ptr->next_out) &&
1841 		       less_eq(msg_seqno(buf_msg(crs)), ackd)) {
1842 			struct sk_buff *next = crs->next;
1843 
1844 			buf_discard(crs);
1845 			crs = next;
1846 			released++;
1847 		}
1848 		if (released) {
1849 			l_ptr->first_out = crs;
1850 			l_ptr->out_queue_size -= released;
1851 		}
1852 		if (unlikely(l_ptr->next_out))
1853 			tipc_link_push_queue(l_ptr);
1854 		if (unlikely(!list_empty(&l_ptr->waiting_ports)))
1855 			tipc_link_wakeup_ports(l_ptr, 0);
1856 		if (unlikely(++l_ptr->unacked_window >= TIPC_MIN_LINK_WIN)) {
1857 			l_ptr->stats.sent_acks++;
1858 			tipc_link_send_proto_msg(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
1859 		}
1860 
1861 protocol_check:
1862 		if (likely(link_working_working(l_ptr))) {
1863 			if (likely(seq_no == mod(l_ptr->next_in_no))) {
1864 				l_ptr->next_in_no++;
1865 				if (unlikely(l_ptr->oldest_deferred_in))
1866 					head = link_insert_deferred_queue(l_ptr,
1867 									  head);
1868 				if (likely(msg_is_dest(msg, tipc_own_addr))) {
1869 deliver:
1870 					if (likely(msg_isdata(msg))) {
1871 						tipc_node_unlock(n_ptr);
1872 						tipc_port_recv_msg(buf);
1873 						continue;
1874 					}
1875 					switch (msg_user(msg)) {
1876 					case MSG_BUNDLER:
1877 						l_ptr->stats.recv_bundles++;
1878 						l_ptr->stats.recv_bundled +=
1879 							msg_msgcnt(msg);
1880 						tipc_node_unlock(n_ptr);
1881 						tipc_link_recv_bundle(buf);
1882 						continue;
1883 					case ROUTE_DISTRIBUTOR:
1884 						tipc_node_unlock(n_ptr);
1885 						tipc_cltr_recv_routing_table(buf);
1886 						continue;
1887 					case NAME_DISTRIBUTOR:
1888 						tipc_node_unlock(n_ptr);
1889 						tipc_named_recv(buf);
1890 						continue;
1891 					case CONN_MANAGER:
1892 						tipc_node_unlock(n_ptr);
1893 						tipc_port_recv_proto_msg(buf);
1894 						continue;
1895 					case MSG_FRAGMENTER:
1896 						l_ptr->stats.recv_fragments++;
1897 						if (tipc_link_recv_fragment(&l_ptr->defragm_buf,
1898 									    &buf, &msg)) {
1899 							l_ptr->stats.recv_fragmented++;
1900 							goto deliver;
1901 						}
1902 						break;
1903 					case CHANGEOVER_PROTOCOL:
1904 						type = msg_type(msg);
1905 						if (link_recv_changeover_msg(&l_ptr, &buf)) {
1906 							msg = buf_msg(buf);
1907 							seq_no = msg_seqno(msg);
1908 							TIPC_SKB_CB(buf)->handle
1909 								= b_ptr;
1910 							if (type == ORIGINAL_MSG)
1911 								goto deliver;
1912 							goto protocol_check;
1913 						}
1914 						break;
1915 					}
1916 				}
1917 				tipc_node_unlock(n_ptr);
1918 				tipc_net_route_msg(buf);
1919 				continue;
1920 			}
1921 			link_handle_out_of_seq_msg(l_ptr, buf);
1922 			head = link_insert_deferred_queue(l_ptr, head);
1923 			tipc_node_unlock(n_ptr);
1924 			continue;
1925 		}
1926 
1927 		if (msg_user(msg) == LINK_PROTOCOL) {
1928 			link_recv_proto_msg(l_ptr, buf);
1929 			head = link_insert_deferred_queue(l_ptr, head);
1930 			tipc_node_unlock(n_ptr);
1931 			continue;
1932 		}
1933 		msg_dbg(msg,"NSEQ<REC<");
1934 		link_state_event(l_ptr, TRAFFIC_MSG_EVT);
1935 
1936 		if (link_working_working(l_ptr)) {
1937 			/* Re-insert in front of queue */
1938 			msg_dbg(msg,"RECV-REINS:");
1939 			buf->next = head;
1940 			head = buf;
1941 			tipc_node_unlock(n_ptr);
1942 			continue;
1943 		}
1944 		tipc_node_unlock(n_ptr);
1945 cont:
1946 		buf_discard(buf);
1947 	}
1948 	read_unlock_bh(&tipc_net_lock);
1949 }
1950 
1951 /*
1952  * link_defer_buf(): Sort a received out-of-sequence packet
1953  *                   into the deferred reception queue.
1954  * Returns the increase of the queue length,i.e. 0 or 1
1955  */
1956 
1957 u32 tipc_link_defer_pkt(struct sk_buff **head,
1958 			struct sk_buff **tail,
1959 			struct sk_buff *buf)
1960 {
1961 	struct sk_buff *prev = NULL;
1962 	struct sk_buff *crs = *head;
1963 	u32 seq_no = msg_seqno(buf_msg(buf));
1964 
1965 	buf->next = NULL;
1966 
1967 	/* Empty queue ? */
1968 	if (*head == NULL) {
1969 		*head = *tail = buf;
1970 		return 1;
1971 	}
1972 
1973 	/* Last ? */
1974 	if (less(msg_seqno(buf_msg(*tail)), seq_no)) {
1975 		(*tail)->next = buf;
1976 		*tail = buf;
1977 		return 1;
1978 	}
1979 
1980 	/* Scan through queue and sort it in */
1981 	do {
1982 		struct tipc_msg *msg = buf_msg(crs);
1983 
1984 		if (less(seq_no, msg_seqno(msg))) {
1985 			buf->next = crs;
1986 			if (prev)
1987 				prev->next = buf;
1988 			else
1989 				*head = buf;
1990 			return 1;
1991 		}
1992 		if (seq_no == msg_seqno(msg)) {
1993 			break;
1994 		}
1995 		prev = crs;
1996 		crs = crs->next;
1997 	}
1998 	while (crs);
1999 
2000 	/* Message is a duplicate of an existing message */
2001 
2002 	buf_discard(buf);
2003 	return 0;
2004 }
2005 
2006 /**
2007  * link_handle_out_of_seq_msg - handle arrival of out-of-sequence packet
2008  */
2009 
2010 static void link_handle_out_of_seq_msg(struct link *l_ptr,
2011 				       struct sk_buff *buf)
2012 {
2013 	u32 seq_no = msg_seqno(buf_msg(buf));
2014 
2015 	if (likely(msg_user(buf_msg(buf)) == LINK_PROTOCOL)) {
2016 		link_recv_proto_msg(l_ptr, buf);
2017 		return;
2018 	}
2019 
2020 	dbg("rx OOS msg: seq_no %u, expecting %u (%u)\n",
2021 	    seq_no, mod(l_ptr->next_in_no), l_ptr->next_in_no);
2022 
2023 	/* Record OOS packet arrival (force mismatch on next timeout) */
2024 
2025 	l_ptr->checkpoint--;
2026 
2027 	/*
2028 	 * Discard packet if a duplicate; otherwise add it to deferred queue
2029 	 * and notify peer of gap as per protocol specification
2030 	 */
2031 
2032 	if (less(seq_no, mod(l_ptr->next_in_no))) {
2033 		l_ptr->stats.duplicates++;
2034 		buf_discard(buf);
2035 		return;
2036 	}
2037 
2038 	if (tipc_link_defer_pkt(&l_ptr->oldest_deferred_in,
2039 				&l_ptr->newest_deferred_in, buf)) {
2040 		l_ptr->deferred_inqueue_sz++;
2041 		l_ptr->stats.deferred_recv++;
2042 		if ((l_ptr->deferred_inqueue_sz % 16) == 1)
2043 			tipc_link_send_proto_msg(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
2044 	} else
2045 		l_ptr->stats.duplicates++;
2046 }
2047 
2048 /*
2049  * Send protocol message to the other endpoint.
2050  */
2051 void tipc_link_send_proto_msg(struct link *l_ptr, u32 msg_typ, int probe_msg,
2052 			      u32 gap, u32 tolerance, u32 priority, u32 ack_mtu)
2053 {
2054 	struct sk_buff *buf = NULL;
2055 	struct tipc_msg *msg = l_ptr->pmsg;
2056         u32 msg_size = sizeof(l_ptr->proto_msg);
2057 
2058 	if (link_blocked(l_ptr))
2059 		return;
2060 	msg_set_type(msg, msg_typ);
2061 	msg_set_net_plane(msg, l_ptr->b_ptr->net_plane);
2062 	msg_set_bcast_ack(msg, mod(l_ptr->owner->bclink.last_in));
2063 	msg_set_last_bcast(msg, tipc_bclink_get_last_sent());
2064 
2065 	if (msg_typ == STATE_MSG) {
2066 		u32 next_sent = mod(l_ptr->next_out_no);
2067 
2068 		if (!tipc_link_is_up(l_ptr))
2069 			return;
2070 		if (l_ptr->next_out)
2071 			next_sent = msg_seqno(buf_msg(l_ptr->next_out));
2072 		msg_set_next_sent(msg, next_sent);
2073 		if (l_ptr->oldest_deferred_in) {
2074 			u32 rec = msg_seqno(buf_msg(l_ptr->oldest_deferred_in));
2075 			gap = mod(rec - mod(l_ptr->next_in_no));
2076 		}
2077 		msg_set_seq_gap(msg, gap);
2078 		if (gap)
2079 			l_ptr->stats.sent_nacks++;
2080 		msg_set_link_tolerance(msg, tolerance);
2081 		msg_set_linkprio(msg, priority);
2082 		msg_set_max_pkt(msg, ack_mtu);
2083 		msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
2084 		msg_set_probe(msg, probe_msg != 0);
2085 		if (probe_msg) {
2086 			u32 mtu = l_ptr->max_pkt;
2087 
2088                         if ((mtu < l_ptr->max_pkt_target) &&
2089 			    link_working_working(l_ptr) &&
2090 			    l_ptr->fsm_msg_cnt) {
2091 				msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
2092                                 if (l_ptr->max_pkt_probes == 10) {
2093                                         l_ptr->max_pkt_target = (msg_size - 4);
2094                                         l_ptr->max_pkt_probes = 0;
2095 					msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
2096                                 }
2097 				l_ptr->max_pkt_probes++;
2098                         }
2099 
2100 			l_ptr->stats.sent_probes++;
2101                 }
2102 		l_ptr->stats.sent_states++;
2103 	} else {		/* RESET_MSG or ACTIVATE_MSG */
2104 		msg_set_ack(msg, mod(l_ptr->reset_checkpoint - 1));
2105 		msg_set_seq_gap(msg, 0);
2106 		msg_set_next_sent(msg, 1);
2107 		msg_set_link_tolerance(msg, l_ptr->tolerance);
2108 		msg_set_linkprio(msg, l_ptr->priority);
2109 		msg_set_max_pkt(msg, l_ptr->max_pkt_target);
2110 	}
2111 
2112 	if (tipc_node_has_redundant_links(l_ptr->owner)) {
2113 		msg_set_redundant_link(msg);
2114 	} else {
2115 		msg_clear_redundant_link(msg);
2116 	}
2117 	msg_set_linkprio(msg, l_ptr->priority);
2118 
2119 	/* Ensure sequence number will not fit : */
2120 
2121 	msg_set_seqno(msg, mod(l_ptr->next_out_no + (0xffff/2)));
2122 
2123 	/* Congestion? */
2124 
2125 	if (tipc_bearer_congested(l_ptr->b_ptr, l_ptr)) {
2126 		if (!l_ptr->proto_msg_queue) {
2127 			l_ptr->proto_msg_queue =
2128 				buf_acquire(sizeof(l_ptr->proto_msg));
2129 		}
2130 		buf = l_ptr->proto_msg_queue;
2131 		if (!buf)
2132 			return;
2133 		memcpy(buf->data, (unchar *)msg, sizeof(l_ptr->proto_msg));
2134 		return;
2135 	}
2136 	msg_set_timestamp(msg, jiffies_to_msecs(jiffies));
2137 
2138 	/* Message can be sent */
2139 
2140 	msg_dbg(msg, ">>");
2141 
2142 	buf = buf_acquire(msg_size);
2143 	if (!buf)
2144 		return;
2145 
2146 	memcpy(buf->data, (unchar *)msg, sizeof(l_ptr->proto_msg));
2147         msg_set_size(buf_msg(buf), msg_size);
2148 
2149 	if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
2150 		l_ptr->unacked_window = 0;
2151 		buf_discard(buf);
2152 		return;
2153 	}
2154 
2155 	/* New congestion */
2156 	tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
2157 	l_ptr->proto_msg_queue = buf;
2158 	l_ptr->stats.bearer_congs++;
2159 }
2160 
2161 /*
2162  * Receive protocol message :
2163  * Note that network plane id propagates through the network, and may
2164  * change at any time. The node with lowest address rules
2165  */
2166 
2167 static void link_recv_proto_msg(struct link *l_ptr, struct sk_buff *buf)
2168 {
2169 	u32 rec_gap = 0;
2170 	u32 max_pkt_info;
2171         u32 max_pkt_ack;
2172 	u32 msg_tol;
2173 	struct tipc_msg *msg = buf_msg(buf);
2174 
2175 	dbg("AT(%u):", jiffies_to_msecs(jiffies));
2176 	msg_dbg(msg, "<<");
2177 	if (link_blocked(l_ptr))
2178 		goto exit;
2179 
2180 	/* record unnumbered packet arrival (force mismatch on next timeout) */
2181 
2182 	l_ptr->checkpoint--;
2183 
2184 	if (l_ptr->b_ptr->net_plane != msg_net_plane(msg))
2185 		if (tipc_own_addr > msg_prevnode(msg))
2186 			l_ptr->b_ptr->net_plane = msg_net_plane(msg);
2187 
2188 	l_ptr->owner->permit_changeover = msg_redundant_link(msg);
2189 
2190 	switch (msg_type(msg)) {
2191 
2192 	case RESET_MSG:
2193 		if (!link_working_unknown(l_ptr) && l_ptr->peer_session) {
2194 			if (msg_session(msg) == l_ptr->peer_session) {
2195 				dbg("Duplicate RESET: %u<->%u\n",
2196 				    msg_session(msg), l_ptr->peer_session);
2197 				break; /* duplicate: ignore */
2198 			}
2199 		}
2200 		/* fall thru' */
2201 	case ACTIVATE_MSG:
2202 		/* Update link settings according other endpoint's values */
2203 
2204 		strcpy((strrchr(l_ptr->name, ':') + 1), (char *)msg_data(msg));
2205 
2206 		if ((msg_tol = msg_link_tolerance(msg)) &&
2207 		    (msg_tol > l_ptr->tolerance))
2208 			link_set_supervision_props(l_ptr, msg_tol);
2209 
2210 		if (msg_linkprio(msg) > l_ptr->priority)
2211 			l_ptr->priority = msg_linkprio(msg);
2212 
2213 		max_pkt_info = msg_max_pkt(msg);
2214                 if (max_pkt_info) {
2215 			if (max_pkt_info < l_ptr->max_pkt_target)
2216 				l_ptr->max_pkt_target = max_pkt_info;
2217 			if (l_ptr->max_pkt > l_ptr->max_pkt_target)
2218 				l_ptr->max_pkt = l_ptr->max_pkt_target;
2219 		} else {
2220                         l_ptr->max_pkt = l_ptr->max_pkt_target;
2221 		}
2222 		l_ptr->owner->bclink.supported = (max_pkt_info != 0);
2223 
2224 		link_state_event(l_ptr, msg_type(msg));
2225 
2226 		l_ptr->peer_session = msg_session(msg);
2227 		l_ptr->peer_bearer_id = msg_bearer_id(msg);
2228 
2229 		/* Synchronize broadcast sequence numbers */
2230 		if (!tipc_node_has_redundant_links(l_ptr->owner)) {
2231 			l_ptr->owner->bclink.last_in = mod(msg_last_bcast(msg));
2232 		}
2233 		break;
2234 	case STATE_MSG:
2235 
2236 		if ((msg_tol = msg_link_tolerance(msg)))
2237 			link_set_supervision_props(l_ptr, msg_tol);
2238 
2239 		if (msg_linkprio(msg) &&
2240 		    (msg_linkprio(msg) != l_ptr->priority)) {
2241 			warn("Resetting link <%s>, priority change %u->%u\n",
2242 			     l_ptr->name, l_ptr->priority, msg_linkprio(msg));
2243 			l_ptr->priority = msg_linkprio(msg);
2244 			tipc_link_reset(l_ptr); /* Enforce change to take effect */
2245 			break;
2246 		}
2247 		link_state_event(l_ptr, TRAFFIC_MSG_EVT);
2248 		l_ptr->stats.recv_states++;
2249 		if (link_reset_unknown(l_ptr))
2250 			break;
2251 
2252 		if (less_eq(mod(l_ptr->next_in_no), msg_next_sent(msg))) {
2253 			rec_gap = mod(msg_next_sent(msg) -
2254 				      mod(l_ptr->next_in_no));
2255 		}
2256 
2257 		max_pkt_ack = msg_max_pkt(msg);
2258                 if (max_pkt_ack > l_ptr->max_pkt) {
2259                         dbg("Link <%s> updated MTU %u -> %u\n",
2260                             l_ptr->name, l_ptr->max_pkt, max_pkt_ack);
2261                         l_ptr->max_pkt = max_pkt_ack;
2262                         l_ptr->max_pkt_probes = 0;
2263                 }
2264 
2265 		max_pkt_ack = 0;
2266                 if (msg_probe(msg)) {
2267 			l_ptr->stats.recv_probes++;
2268                         if (msg_size(msg) > sizeof(l_ptr->proto_msg)) {
2269                                 max_pkt_ack = msg_size(msg);
2270                         }
2271                 }
2272 
2273 		/* Protocol message before retransmits, reduce loss risk */
2274 
2275 		tipc_bclink_check_gap(l_ptr->owner, msg_last_bcast(msg));
2276 
2277 		if (rec_gap || (msg_probe(msg))) {
2278 			tipc_link_send_proto_msg(l_ptr, STATE_MSG,
2279 						 0, rec_gap, 0, 0, max_pkt_ack);
2280 		}
2281 		if (msg_seq_gap(msg)) {
2282 			msg_dbg(msg, "With Gap:");
2283 			l_ptr->stats.recv_nacks++;
2284 			tipc_link_retransmit(l_ptr, l_ptr->first_out,
2285 					     msg_seq_gap(msg));
2286 		}
2287 		break;
2288 	default:
2289 		msg_dbg(buf_msg(buf), "<DISCARDING UNKNOWN<");
2290 	}
2291 exit:
2292 	buf_discard(buf);
2293 }
2294 
2295 
2296 /*
2297  * tipc_link_tunnel(): Send one message via a link belonging to
2298  * another bearer. Owner node is locked.
2299  */
2300 void tipc_link_tunnel(struct link *l_ptr,
2301 		      struct tipc_msg *tunnel_hdr,
2302 		      struct tipc_msg  *msg,
2303 		      u32 selector)
2304 {
2305 	struct link *tunnel;
2306 	struct sk_buff *buf;
2307 	u32 length = msg_size(msg);
2308 
2309 	tunnel = l_ptr->owner->active_links[selector & 1];
2310 	if (!tipc_link_is_up(tunnel)) {
2311 		warn("Link changeover error, "
2312 		     "tunnel link no longer available\n");
2313 		return;
2314 	}
2315 	msg_set_size(tunnel_hdr, length + INT_H_SIZE);
2316 	buf = buf_acquire(length + INT_H_SIZE);
2317 	if (!buf) {
2318 		warn("Link changeover error, "
2319 		     "unable to send tunnel msg\n");
2320 		return;
2321 	}
2322 	memcpy(buf->data, (unchar *)tunnel_hdr, INT_H_SIZE);
2323 	memcpy(buf->data + INT_H_SIZE, (unchar *)msg, length);
2324 	dbg("%c->%c:", l_ptr->b_ptr->net_plane, tunnel->b_ptr->net_plane);
2325 	msg_dbg(buf_msg(buf), ">SEND>");
2326 	tipc_link_send_buf(tunnel, buf);
2327 }
2328 
2329 
2330 
2331 /*
2332  * changeover(): Send whole message queue via the remaining link
2333  *               Owner node is locked.
2334  */
2335 
2336 void tipc_link_changeover(struct link *l_ptr)
2337 {
2338 	u32 msgcount = l_ptr->out_queue_size;
2339 	struct sk_buff *crs = l_ptr->first_out;
2340 	struct link *tunnel = l_ptr->owner->active_links[0];
2341 	struct tipc_msg tunnel_hdr;
2342 	int split_bundles;
2343 
2344 	if (!tunnel)
2345 		return;
2346 
2347 	if (!l_ptr->owner->permit_changeover) {
2348 		warn("Link changeover error, "
2349 		     "peer did not permit changeover\n");
2350 		return;
2351 	}
2352 
2353 	msg_init(&tunnel_hdr, CHANGEOVER_PROTOCOL,
2354 		 ORIGINAL_MSG, TIPC_OK, INT_H_SIZE, l_ptr->addr);
2355 	msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
2356 	msg_set_msgcnt(&tunnel_hdr, msgcount);
2357 	dbg("Link changeover requires %u tunnel messages\n", msgcount);
2358 
2359 	if (!l_ptr->first_out) {
2360 		struct sk_buff *buf;
2361 
2362 		buf = buf_acquire(INT_H_SIZE);
2363 		if (buf) {
2364 			memcpy(buf->data, (unchar *)&tunnel_hdr, INT_H_SIZE);
2365 			msg_set_size(&tunnel_hdr, INT_H_SIZE);
2366 			dbg("%c->%c:", l_ptr->b_ptr->net_plane,
2367 			    tunnel->b_ptr->net_plane);
2368 			msg_dbg(&tunnel_hdr, "EMPTY>SEND>");
2369 			tipc_link_send_buf(tunnel, buf);
2370 		} else {
2371 			warn("Link changeover error, "
2372 			     "unable to send changeover msg\n");
2373 		}
2374 		return;
2375 	}
2376 
2377 	split_bundles = (l_ptr->owner->active_links[0] !=
2378 			 l_ptr->owner->active_links[1]);
2379 
2380 	while (crs) {
2381 		struct tipc_msg *msg = buf_msg(crs);
2382 
2383 		if ((msg_user(msg) == MSG_BUNDLER) && split_bundles) {
2384 			u32 msgcount = msg_msgcnt(msg);
2385 			struct tipc_msg *m = msg_get_wrapped(msg);
2386 			unchar* pos = (unchar*)m;
2387 
2388 			while (msgcount--) {
2389 				msg_set_seqno(m,msg_seqno(msg));
2390 				tipc_link_tunnel(l_ptr, &tunnel_hdr, m,
2391 						 msg_link_selector(m));
2392 				pos += align(msg_size(m));
2393 				m = (struct tipc_msg *)pos;
2394 			}
2395 		} else {
2396 			tipc_link_tunnel(l_ptr, &tunnel_hdr, msg,
2397 					 msg_link_selector(msg));
2398 		}
2399 		crs = crs->next;
2400 	}
2401 }
2402 
2403 void tipc_link_send_duplicate(struct link *l_ptr, struct link *tunnel)
2404 {
2405 	struct sk_buff *iter;
2406 	struct tipc_msg tunnel_hdr;
2407 
2408 	msg_init(&tunnel_hdr, CHANGEOVER_PROTOCOL,
2409 		 DUPLICATE_MSG, TIPC_OK, INT_H_SIZE, l_ptr->addr);
2410 	msg_set_msgcnt(&tunnel_hdr, l_ptr->out_queue_size);
2411 	msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
2412 	iter = l_ptr->first_out;
2413 	while (iter) {
2414 		struct sk_buff *outbuf;
2415 		struct tipc_msg *msg = buf_msg(iter);
2416 		u32 length = msg_size(msg);
2417 
2418 		if (msg_user(msg) == MSG_BUNDLER)
2419 			msg_set_type(msg, CLOSED_MSG);
2420 		msg_set_ack(msg, mod(l_ptr->next_in_no - 1));	/* Update */
2421 		msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
2422 		msg_set_size(&tunnel_hdr, length + INT_H_SIZE);
2423 		outbuf = buf_acquire(length + INT_H_SIZE);
2424 		if (outbuf == NULL) {
2425 			warn("Link changeover error, "
2426 			     "unable to send duplicate msg\n");
2427 			return;
2428 		}
2429 		memcpy(outbuf->data, (unchar *)&tunnel_hdr, INT_H_SIZE);
2430 		memcpy(outbuf->data + INT_H_SIZE, iter->data, length);
2431 		dbg("%c->%c:", l_ptr->b_ptr->net_plane,
2432 		    tunnel->b_ptr->net_plane);
2433 		msg_dbg(buf_msg(outbuf), ">SEND>");
2434 		tipc_link_send_buf(tunnel, outbuf);
2435 		if (!tipc_link_is_up(l_ptr))
2436 			return;
2437 		iter = iter->next;
2438 	}
2439 }
2440 
2441 
2442 
2443 /**
2444  * buf_extract - extracts embedded TIPC message from another message
2445  * @skb: encapsulating message buffer
2446  * @from_pos: offset to extract from
2447  *
2448  * Returns a new message buffer containing an embedded message.  The
2449  * encapsulating message itself is left unchanged.
2450  */
2451 
2452 static struct sk_buff *buf_extract(struct sk_buff *skb, u32 from_pos)
2453 {
2454 	struct tipc_msg *msg = (struct tipc_msg *)(skb->data + from_pos);
2455 	u32 size = msg_size(msg);
2456 	struct sk_buff *eb;
2457 
2458 	eb = buf_acquire(size);
2459 	if (eb)
2460 		memcpy(eb->data, (unchar *)msg, size);
2461 	return eb;
2462 }
2463 
2464 /*
2465  *  link_recv_changeover_msg(): Receive tunneled packet sent
2466  *  via other link. Node is locked. Return extracted buffer.
2467  */
2468 
2469 static int link_recv_changeover_msg(struct link **l_ptr,
2470 				    struct sk_buff **buf)
2471 {
2472 	struct sk_buff *tunnel_buf = *buf;
2473 	struct link *dest_link;
2474 	struct tipc_msg *msg;
2475 	struct tipc_msg *tunnel_msg = buf_msg(tunnel_buf);
2476 	u32 msg_typ = msg_type(tunnel_msg);
2477 	u32 msg_count = msg_msgcnt(tunnel_msg);
2478 
2479 	dest_link = (*l_ptr)->owner->links[msg_bearer_id(tunnel_msg)];
2480 	if (!dest_link) {
2481 		msg_dbg(tunnel_msg, "NOLINK/<REC<");
2482 		goto exit;
2483 	}
2484 	if (dest_link == *l_ptr) {
2485 		err("Unexpected changeover message on link <%s>\n",
2486 		    (*l_ptr)->name);
2487 		goto exit;
2488 	}
2489 	dbg("%c<-%c:", dest_link->b_ptr->net_plane,
2490 	    (*l_ptr)->b_ptr->net_plane);
2491 	*l_ptr = dest_link;
2492 	msg = msg_get_wrapped(tunnel_msg);
2493 
2494 	if (msg_typ == DUPLICATE_MSG) {
2495 		if (less(msg_seqno(msg), mod(dest_link->next_in_no))) {
2496 			msg_dbg(tunnel_msg, "DROP/<REC<");
2497 			goto exit;
2498 		}
2499 		*buf = buf_extract(tunnel_buf,INT_H_SIZE);
2500 		if (*buf == NULL) {
2501 			warn("Link changeover error, duplicate msg dropped\n");
2502 			goto exit;
2503 		}
2504 		msg_dbg(tunnel_msg, "TNL<REC<");
2505 		buf_discard(tunnel_buf);
2506 		return 1;
2507 	}
2508 
2509 	/* First original message ?: */
2510 
2511 	if (tipc_link_is_up(dest_link)) {
2512 		msg_dbg(tunnel_msg, "UP/FIRST/<REC<");
2513 		info("Resetting link <%s>, changeover initiated by peer\n",
2514 		     dest_link->name);
2515 		tipc_link_reset(dest_link);
2516 		dest_link->exp_msg_count = msg_count;
2517 		dbg("Expecting %u tunnelled messages\n", msg_count);
2518 		if (!msg_count)
2519 			goto exit;
2520 	} else if (dest_link->exp_msg_count == START_CHANGEOVER) {
2521 		msg_dbg(tunnel_msg, "BLK/FIRST/<REC<");
2522 		dest_link->exp_msg_count = msg_count;
2523 		dbg("Expecting %u tunnelled messages\n", msg_count);
2524 		if (!msg_count)
2525 			goto exit;
2526 	}
2527 
2528 	/* Receive original message */
2529 
2530 	if (dest_link->exp_msg_count == 0) {
2531 		warn("Link switchover error, "
2532 		     "got too many tunnelled messages\n");
2533 		msg_dbg(tunnel_msg, "OVERDUE/DROP/<REC<");
2534 		dbg_print_link(dest_link, "LINK:");
2535 		goto exit;
2536 	}
2537 	dest_link->exp_msg_count--;
2538 	if (less(msg_seqno(msg), dest_link->reset_checkpoint)) {
2539 		msg_dbg(tunnel_msg, "DROP/DUPL/<REC<");
2540 		goto exit;
2541 	} else {
2542 		*buf = buf_extract(tunnel_buf, INT_H_SIZE);
2543 		if (*buf != NULL) {
2544 			msg_dbg(tunnel_msg, "TNL<REC<");
2545 			buf_discard(tunnel_buf);
2546 			return 1;
2547 		} else {
2548 			warn("Link changeover error, original msg dropped\n");
2549 		}
2550 	}
2551 exit:
2552 	*buf = NULL;
2553 	buf_discard(tunnel_buf);
2554 	return 0;
2555 }
2556 
2557 /*
2558  *  Bundler functionality:
2559  */
2560 void tipc_link_recv_bundle(struct sk_buff *buf)
2561 {
2562 	u32 msgcount = msg_msgcnt(buf_msg(buf));
2563 	u32 pos = INT_H_SIZE;
2564 	struct sk_buff *obuf;
2565 
2566 	msg_dbg(buf_msg(buf), "<BNDL<: ");
2567 	while (msgcount--) {
2568 		obuf = buf_extract(buf, pos);
2569 		if (obuf == NULL) {
2570 			warn("Link unable to unbundle message(s)\n");
2571 			break;
2572 		};
2573 		pos += align(msg_size(buf_msg(obuf)));
2574 		msg_dbg(buf_msg(obuf), "     /");
2575 		tipc_net_route_msg(obuf);
2576 	}
2577 	buf_discard(buf);
2578 }
2579 
2580 /*
2581  *  Fragmentation/defragmentation:
2582  */
2583 
2584 
2585 /*
2586  * tipc_link_send_long_buf: Entry for buffers needing fragmentation.
2587  * The buffer is complete, inclusive total message length.
2588  * Returns user data length.
2589  */
2590 int tipc_link_send_long_buf(struct link *l_ptr, struct sk_buff *buf)
2591 {
2592 	struct tipc_msg *inmsg = buf_msg(buf);
2593 	struct tipc_msg fragm_hdr;
2594 	u32 insize = msg_size(inmsg);
2595 	u32 dsz = msg_data_sz(inmsg);
2596 	unchar *crs = buf->data;
2597 	u32 rest = insize;
2598 	u32 pack_sz = link_max_pkt(l_ptr);
2599 	u32 fragm_sz = pack_sz - INT_H_SIZE;
2600 	u32 fragm_no = 1;
2601 	u32 destaddr = msg_destnode(inmsg);
2602 
2603 	if (msg_short(inmsg))
2604 		destaddr = l_ptr->addr;
2605 
2606 	if (msg_routed(inmsg))
2607 		msg_set_prevnode(inmsg, tipc_own_addr);
2608 
2609 	/* Prepare reusable fragment header: */
2610 
2611 	msg_init(&fragm_hdr, MSG_FRAGMENTER, FIRST_FRAGMENT,
2612 		 TIPC_OK, INT_H_SIZE, destaddr);
2613 	msg_set_link_selector(&fragm_hdr, msg_link_selector(inmsg));
2614 	msg_set_long_msgno(&fragm_hdr, mod(l_ptr->long_msg_seq_no++));
2615 	msg_set_fragm_no(&fragm_hdr, fragm_no);
2616 	l_ptr->stats.sent_fragmented++;
2617 
2618 	/* Chop up message: */
2619 
2620 	while (rest > 0) {
2621 		struct sk_buff *fragm;
2622 
2623 		if (rest <= fragm_sz) {
2624 			fragm_sz = rest;
2625 			msg_set_type(&fragm_hdr, LAST_FRAGMENT);
2626 		}
2627 		fragm = buf_acquire(fragm_sz + INT_H_SIZE);
2628 		if (fragm == NULL) {
2629 			warn("Link unable to fragment message\n");
2630 			dsz = -ENOMEM;
2631 			goto exit;
2632 		}
2633 		msg_set_size(&fragm_hdr, fragm_sz + INT_H_SIZE);
2634 		memcpy(fragm->data, (unchar *)&fragm_hdr, INT_H_SIZE);
2635 		memcpy(fragm->data + INT_H_SIZE, crs, fragm_sz);
2636 
2637 		/*  Send queued messages first, if any: */
2638 
2639 		l_ptr->stats.sent_fragments++;
2640 		tipc_link_send_buf(l_ptr, fragm);
2641 		if (!tipc_link_is_up(l_ptr))
2642 			return dsz;
2643 		msg_set_fragm_no(&fragm_hdr, ++fragm_no);
2644 		rest -= fragm_sz;
2645 		crs += fragm_sz;
2646 		msg_set_type(&fragm_hdr, FRAGMENT);
2647 	}
2648 exit:
2649 	buf_discard(buf);
2650 	return dsz;
2651 }
2652 
2653 /*
2654  * A pending message being re-assembled must store certain values
2655  * to handle subsequent fragments correctly. The following functions
2656  * help storing these values in unused, available fields in the
2657  * pending message. This makes dynamic memory allocation unecessary.
2658  */
2659 
2660 static void set_long_msg_seqno(struct sk_buff *buf, u32 seqno)
2661 {
2662 	msg_set_seqno(buf_msg(buf), seqno);
2663 }
2664 
2665 static u32 get_fragm_size(struct sk_buff *buf)
2666 {
2667 	return msg_ack(buf_msg(buf));
2668 }
2669 
2670 static void set_fragm_size(struct sk_buff *buf, u32 sz)
2671 {
2672 	msg_set_ack(buf_msg(buf), sz);
2673 }
2674 
2675 static u32 get_expected_frags(struct sk_buff *buf)
2676 {
2677 	return msg_bcast_ack(buf_msg(buf));
2678 }
2679 
2680 static void set_expected_frags(struct sk_buff *buf, u32 exp)
2681 {
2682 	msg_set_bcast_ack(buf_msg(buf), exp);
2683 }
2684 
2685 static u32 get_timer_cnt(struct sk_buff *buf)
2686 {
2687 	return msg_reroute_cnt(buf_msg(buf));
2688 }
2689 
2690 static void incr_timer_cnt(struct sk_buff *buf)
2691 {
2692 	msg_incr_reroute_cnt(buf_msg(buf));
2693 }
2694 
2695 /*
2696  * tipc_link_recv_fragment(): Called with node lock on. Returns
2697  * the reassembled buffer if message is complete.
2698  */
2699 int tipc_link_recv_fragment(struct sk_buff **pending, struct sk_buff **fb,
2700 			    struct tipc_msg **m)
2701 {
2702 	struct sk_buff *prev = NULL;
2703 	struct sk_buff *fbuf = *fb;
2704 	struct tipc_msg *fragm = buf_msg(fbuf);
2705 	struct sk_buff *pbuf = *pending;
2706 	u32 long_msg_seq_no = msg_long_msgno(fragm);
2707 
2708 	*fb = NULL;
2709 	msg_dbg(fragm,"FRG<REC<");
2710 
2711 	/* Is there an incomplete message waiting for this fragment? */
2712 
2713 	while (pbuf && ((msg_seqno(buf_msg(pbuf)) != long_msg_seq_no)
2714 			|| (msg_orignode(fragm) != msg_orignode(buf_msg(pbuf))))) {
2715 		prev = pbuf;
2716 		pbuf = pbuf->next;
2717 	}
2718 
2719 	if (!pbuf && (msg_type(fragm) == FIRST_FRAGMENT)) {
2720 		struct tipc_msg *imsg = (struct tipc_msg *)msg_data(fragm);
2721 		u32 msg_sz = msg_size(imsg);
2722 		u32 fragm_sz = msg_data_sz(fragm);
2723 		u32 exp_fragm_cnt = msg_sz/fragm_sz + !!(msg_sz % fragm_sz);
2724 		u32 max =  TIPC_MAX_USER_MSG_SIZE + LONG_H_SIZE;
2725 		if (msg_type(imsg) == TIPC_MCAST_MSG)
2726 			max = TIPC_MAX_USER_MSG_SIZE + MCAST_H_SIZE;
2727 		if (msg_size(imsg) > max) {
2728 			msg_dbg(fragm,"<REC<Oversized: ");
2729 			buf_discard(fbuf);
2730 			return 0;
2731 		}
2732 		pbuf = buf_acquire(msg_size(imsg));
2733 		if (pbuf != NULL) {
2734 			pbuf->next = *pending;
2735 			*pending = pbuf;
2736 			memcpy(pbuf->data, (unchar *)imsg, msg_data_sz(fragm));
2737 
2738 			/*  Prepare buffer for subsequent fragments. */
2739 
2740 			set_long_msg_seqno(pbuf, long_msg_seq_no);
2741 			set_fragm_size(pbuf,fragm_sz);
2742 			set_expected_frags(pbuf,exp_fragm_cnt - 1);
2743 		} else {
2744 			warn("Link unable to reassemble fragmented message\n");
2745 		}
2746 		buf_discard(fbuf);
2747 		return 0;
2748 	} else if (pbuf && (msg_type(fragm) != FIRST_FRAGMENT)) {
2749 		u32 dsz = msg_data_sz(fragm);
2750 		u32 fsz = get_fragm_size(pbuf);
2751 		u32 crs = ((msg_fragm_no(fragm) - 1) * fsz);
2752 		u32 exp_frags = get_expected_frags(pbuf) - 1;
2753 		memcpy(pbuf->data + crs, msg_data(fragm), dsz);
2754 		buf_discard(fbuf);
2755 
2756 		/* Is message complete? */
2757 
2758 		if (exp_frags == 0) {
2759 			if (prev)
2760 				prev->next = pbuf->next;
2761 			else
2762 				*pending = pbuf->next;
2763 			msg_reset_reroute_cnt(buf_msg(pbuf));
2764 			*fb = pbuf;
2765 			*m = buf_msg(pbuf);
2766 			return 1;
2767 		}
2768 		set_expected_frags(pbuf,exp_frags);
2769 		return 0;
2770 	}
2771 	dbg(" Discarding orphan fragment %x\n",fbuf);
2772 	msg_dbg(fragm,"ORPHAN:");
2773 	dbg("Pending long buffers:\n");
2774 	dbg_print_buf_chain(*pending);
2775 	buf_discard(fbuf);
2776 	return 0;
2777 }
2778 
2779 /**
2780  * link_check_defragm_bufs - flush stale incoming message fragments
2781  * @l_ptr: pointer to link
2782  */
2783 
2784 static void link_check_defragm_bufs(struct link *l_ptr)
2785 {
2786 	struct sk_buff *prev = NULL;
2787 	struct sk_buff *next = NULL;
2788 	struct sk_buff *buf = l_ptr->defragm_buf;
2789 
2790 	if (!buf)
2791 		return;
2792 	if (!link_working_working(l_ptr))
2793 		return;
2794 	while (buf) {
2795 		u32 cnt = get_timer_cnt(buf);
2796 
2797 		next = buf->next;
2798 		if (cnt < 4) {
2799 			incr_timer_cnt(buf);
2800 			prev = buf;
2801 		} else {
2802 			dbg(" Discarding incomplete long buffer\n");
2803 			msg_dbg(buf_msg(buf), "LONG:");
2804 			dbg_print_link(l_ptr, "curr:");
2805 			dbg("Pending long buffers:\n");
2806 			dbg_print_buf_chain(l_ptr->defragm_buf);
2807 			if (prev)
2808 				prev->next = buf->next;
2809 			else
2810 				l_ptr->defragm_buf = buf->next;
2811 			buf_discard(buf);
2812 		}
2813 		buf = next;
2814 	}
2815 }
2816 
2817 
2818 
2819 static void link_set_supervision_props(struct link *l_ptr, u32 tolerance)
2820 {
2821 	l_ptr->tolerance = tolerance;
2822 	l_ptr->continuity_interval =
2823 		((tolerance / 4) > 500) ? 500 : tolerance / 4;
2824 	l_ptr->abort_limit = tolerance / (l_ptr->continuity_interval / 4);
2825 }
2826 
2827 
2828 void tipc_link_set_queue_limits(struct link *l_ptr, u32 window)
2829 {
2830 	/* Data messages from this node, inclusive FIRST_FRAGM */
2831 	l_ptr->queue_limit[DATA_LOW] = window;
2832 	l_ptr->queue_limit[DATA_MEDIUM] = (window / 3) * 4;
2833 	l_ptr->queue_limit[DATA_HIGH] = (window / 3) * 5;
2834 	l_ptr->queue_limit[DATA_CRITICAL] = (window / 3) * 6;
2835 	/* Transiting data messages,inclusive FIRST_FRAGM */
2836 	l_ptr->queue_limit[DATA_LOW + 4] = 300;
2837 	l_ptr->queue_limit[DATA_MEDIUM + 4] = 600;
2838 	l_ptr->queue_limit[DATA_HIGH + 4] = 900;
2839 	l_ptr->queue_limit[DATA_CRITICAL + 4] = 1200;
2840 	l_ptr->queue_limit[CONN_MANAGER] = 1200;
2841 	l_ptr->queue_limit[ROUTE_DISTRIBUTOR] = 1200;
2842 	l_ptr->queue_limit[CHANGEOVER_PROTOCOL] = 2500;
2843 	l_ptr->queue_limit[NAME_DISTRIBUTOR] = 3000;
2844 	/* FRAGMENT and LAST_FRAGMENT packets */
2845 	l_ptr->queue_limit[MSG_FRAGMENTER] = 4000;
2846 }
2847 
2848 /**
2849  * link_find_link - locate link by name
2850  * @name - ptr to link name string
2851  * @node - ptr to area to be filled with ptr to associated node
2852  *
2853  * Caller must hold 'tipc_net_lock' to ensure node and bearer are not deleted;
2854  * this also prevents link deletion.
2855  *
2856  * Returns pointer to link (or 0 if invalid link name).
2857  */
2858 
2859 static struct link *link_find_link(const char *name, struct node **node)
2860 {
2861 	struct link_name link_name_parts;
2862 	struct bearer *b_ptr;
2863 	struct link *l_ptr;
2864 
2865 	if (!link_name_validate(name, &link_name_parts))
2866 		return NULL;
2867 
2868 	b_ptr = tipc_bearer_find_interface(link_name_parts.if_local);
2869 	if (!b_ptr)
2870 		return NULL;
2871 
2872 	*node = tipc_node_find(link_name_parts.addr_peer);
2873 	if (!*node)
2874 		return NULL;
2875 
2876 	l_ptr = (*node)->links[b_ptr->identity];
2877 	if (!l_ptr || strcmp(l_ptr->name, name))
2878 		return NULL;
2879 
2880 	return l_ptr;
2881 }
2882 
2883 struct sk_buff *tipc_link_cmd_config(const void *req_tlv_area, int req_tlv_space,
2884 				     u16 cmd)
2885 {
2886 	struct tipc_link_config *args;
2887         u32 new_value;
2888 	struct link *l_ptr;
2889 	struct node *node;
2890         int res;
2891 
2892 	if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_CONFIG))
2893 		return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2894 
2895 	args = (struct tipc_link_config *)TLV_DATA(req_tlv_area);
2896 	new_value = ntohl(args->value);
2897 
2898 	if (!strcmp(args->name, tipc_bclink_name)) {
2899 		if ((cmd == TIPC_CMD_SET_LINK_WINDOW) &&
2900 		    (tipc_bclink_set_queue_limits(new_value) == 0))
2901 			return tipc_cfg_reply_none();
2902 	       	return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
2903 						   " (cannot change setting on broadcast link)");
2904 	}
2905 
2906 	read_lock_bh(&tipc_net_lock);
2907 	l_ptr = link_find_link(args->name, &node);
2908 	if (!l_ptr) {
2909 		read_unlock_bh(&tipc_net_lock);
2910 	       	return tipc_cfg_reply_error_string("link not found");
2911 	}
2912 
2913 	tipc_node_lock(node);
2914 	res = -EINVAL;
2915 	switch (cmd) {
2916 	case TIPC_CMD_SET_LINK_TOL:
2917 		if ((new_value >= TIPC_MIN_LINK_TOL) &&
2918 		    (new_value <= TIPC_MAX_LINK_TOL)) {
2919 			link_set_supervision_props(l_ptr, new_value);
2920 			tipc_link_send_proto_msg(l_ptr, STATE_MSG,
2921 						 0, 0, new_value, 0, 0);
2922 			res = TIPC_OK;
2923 		}
2924 		break;
2925 	case TIPC_CMD_SET_LINK_PRI:
2926 		if ((new_value >= TIPC_MIN_LINK_PRI) &&
2927 		    (new_value <= TIPC_MAX_LINK_PRI)) {
2928 			l_ptr->priority = new_value;
2929 			tipc_link_send_proto_msg(l_ptr, STATE_MSG,
2930 						 0, 0, 0, new_value, 0);
2931 			res = TIPC_OK;
2932 		}
2933 		break;
2934 	case TIPC_CMD_SET_LINK_WINDOW:
2935 		if ((new_value >= TIPC_MIN_LINK_WIN) &&
2936 		    (new_value <= TIPC_MAX_LINK_WIN)) {
2937 			tipc_link_set_queue_limits(l_ptr, new_value);
2938 			res = TIPC_OK;
2939 		}
2940 		break;
2941 	}
2942 	tipc_node_unlock(node);
2943 
2944 	read_unlock_bh(&tipc_net_lock);
2945 	if (res)
2946 	       	return tipc_cfg_reply_error_string("cannot change link setting");
2947 
2948 	return tipc_cfg_reply_none();
2949 }
2950 
2951 /**
2952  * link_reset_statistics - reset link statistics
2953  * @l_ptr: pointer to link
2954  */
2955 
2956 static void link_reset_statistics(struct link *l_ptr)
2957 {
2958 	memset(&l_ptr->stats, 0, sizeof(l_ptr->stats));
2959 	l_ptr->stats.sent_info = l_ptr->next_out_no;
2960 	l_ptr->stats.recv_info = l_ptr->next_in_no;
2961 }
2962 
2963 struct sk_buff *tipc_link_cmd_reset_stats(const void *req_tlv_area, int req_tlv_space)
2964 {
2965 	char *link_name;
2966 	struct link *l_ptr;
2967 	struct node *node;
2968 
2969 	if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_NAME))
2970 		return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2971 
2972 	link_name = (char *)TLV_DATA(req_tlv_area);
2973 	if (!strcmp(link_name, tipc_bclink_name)) {
2974 		if (tipc_bclink_reset_stats())
2975 			return tipc_cfg_reply_error_string("link not found");
2976 		return tipc_cfg_reply_none();
2977 	}
2978 
2979 	read_lock_bh(&tipc_net_lock);
2980 	l_ptr = link_find_link(link_name, &node);
2981 	if (!l_ptr) {
2982 		read_unlock_bh(&tipc_net_lock);
2983 		return tipc_cfg_reply_error_string("link not found");
2984 	}
2985 
2986 	tipc_node_lock(node);
2987 	link_reset_statistics(l_ptr);
2988 	tipc_node_unlock(node);
2989 	read_unlock_bh(&tipc_net_lock);
2990 	return tipc_cfg_reply_none();
2991 }
2992 
2993 /**
2994  * percent - convert count to a percentage of total (rounding up or down)
2995  */
2996 
2997 static u32 percent(u32 count, u32 total)
2998 {
2999 	return (count * 100 + (total / 2)) / total;
3000 }
3001 
3002 /**
3003  * tipc_link_stats - print link statistics
3004  * @name: link name
3005  * @buf: print buffer area
3006  * @buf_size: size of print buffer area
3007  *
3008  * Returns length of print buffer data string (or 0 if error)
3009  */
3010 
3011 static int tipc_link_stats(const char *name, char *buf, const u32 buf_size)
3012 {
3013 	struct print_buf pb;
3014 	struct link *l_ptr;
3015 	struct node *node;
3016 	char *status;
3017 	u32 profile_total = 0;
3018 
3019 	if (!strcmp(name, tipc_bclink_name))
3020 		return tipc_bclink_stats(buf, buf_size);
3021 
3022 	tipc_printbuf_init(&pb, buf, buf_size);
3023 
3024 	read_lock_bh(&tipc_net_lock);
3025 	l_ptr = link_find_link(name, &node);
3026 	if (!l_ptr) {
3027 		read_unlock_bh(&tipc_net_lock);
3028 		return 0;
3029 	}
3030 	tipc_node_lock(node);
3031 
3032 	if (tipc_link_is_active(l_ptr))
3033 		status = "ACTIVE";
3034 	else if (tipc_link_is_up(l_ptr))
3035 		status = "STANDBY";
3036 	else
3037 		status = "DEFUNCT";
3038 	tipc_printf(&pb, "Link <%s>\n"
3039 		         "  %s  MTU:%u  Priority:%u  Tolerance:%u ms"
3040 		         "  Window:%u packets\n",
3041 		    l_ptr->name, status, link_max_pkt(l_ptr),
3042 		    l_ptr->priority, l_ptr->tolerance, l_ptr->queue_limit[0]);
3043 	tipc_printf(&pb, "  RX packets:%u fragments:%u/%u bundles:%u/%u\n",
3044 		    l_ptr->next_in_no - l_ptr->stats.recv_info,
3045 		    l_ptr->stats.recv_fragments,
3046 		    l_ptr->stats.recv_fragmented,
3047 		    l_ptr->stats.recv_bundles,
3048 		    l_ptr->stats.recv_bundled);
3049 	tipc_printf(&pb, "  TX packets:%u fragments:%u/%u bundles:%u/%u\n",
3050 		    l_ptr->next_out_no - l_ptr->stats.sent_info,
3051 		    l_ptr->stats.sent_fragments,
3052 		    l_ptr->stats.sent_fragmented,
3053 		    l_ptr->stats.sent_bundles,
3054 		    l_ptr->stats.sent_bundled);
3055 	profile_total = l_ptr->stats.msg_length_counts;
3056 	if (!profile_total)
3057 		profile_total = 1;
3058 	tipc_printf(&pb, "  TX profile sample:%u packets  average:%u octets\n"
3059 		         "  0-64:%u%% -256:%u%% -1024:%u%% -4096:%u%% "
3060 		         "-16354:%u%% -32768:%u%% -66000:%u%%\n",
3061 		    l_ptr->stats.msg_length_counts,
3062 		    l_ptr->stats.msg_lengths_total / profile_total,
3063 		    percent(l_ptr->stats.msg_length_profile[0], profile_total),
3064 		    percent(l_ptr->stats.msg_length_profile[1], profile_total),
3065 		    percent(l_ptr->stats.msg_length_profile[2], profile_total),
3066 		    percent(l_ptr->stats.msg_length_profile[3], profile_total),
3067 		    percent(l_ptr->stats.msg_length_profile[4], profile_total),
3068 		    percent(l_ptr->stats.msg_length_profile[5], profile_total),
3069 		    percent(l_ptr->stats.msg_length_profile[6], profile_total));
3070 	tipc_printf(&pb, "  RX states:%u probes:%u naks:%u defs:%u dups:%u\n",
3071 		    l_ptr->stats.recv_states,
3072 		    l_ptr->stats.recv_probes,
3073 		    l_ptr->stats.recv_nacks,
3074 		    l_ptr->stats.deferred_recv,
3075 		    l_ptr->stats.duplicates);
3076 	tipc_printf(&pb, "  TX states:%u probes:%u naks:%u acks:%u dups:%u\n",
3077 		    l_ptr->stats.sent_states,
3078 		    l_ptr->stats.sent_probes,
3079 		    l_ptr->stats.sent_nacks,
3080 		    l_ptr->stats.sent_acks,
3081 		    l_ptr->stats.retransmitted);
3082 	tipc_printf(&pb, "  Congestion bearer:%u link:%u  Send queue max:%u avg:%u\n",
3083 		    l_ptr->stats.bearer_congs,
3084 		    l_ptr->stats.link_congs,
3085 		    l_ptr->stats.max_queue_sz,
3086 		    l_ptr->stats.queue_sz_counts
3087 		    ? (l_ptr->stats.accu_queue_sz / l_ptr->stats.queue_sz_counts)
3088 		    : 0);
3089 
3090 	tipc_node_unlock(node);
3091 	read_unlock_bh(&tipc_net_lock);
3092 	return tipc_printbuf_validate(&pb);
3093 }
3094 
3095 #define MAX_LINK_STATS_INFO 2000
3096 
3097 struct sk_buff *tipc_link_cmd_show_stats(const void *req_tlv_area, int req_tlv_space)
3098 {
3099 	struct sk_buff *buf;
3100 	struct tlv_desc *rep_tlv;
3101 	int str_len;
3102 
3103 	if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_NAME))
3104 		return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
3105 
3106 	buf = tipc_cfg_reply_alloc(TLV_SPACE(MAX_LINK_STATS_INFO));
3107 	if (!buf)
3108 		return NULL;
3109 
3110 	rep_tlv = (struct tlv_desc *)buf->data;
3111 
3112 	str_len = tipc_link_stats((char *)TLV_DATA(req_tlv_area),
3113 				  (char *)TLV_DATA(rep_tlv), MAX_LINK_STATS_INFO);
3114 	if (!str_len) {
3115 		buf_discard(buf);
3116 	       	return tipc_cfg_reply_error_string("link not found");
3117 	}
3118 
3119 	skb_put(buf, TLV_SPACE(str_len));
3120 	TLV_SET(rep_tlv, TIPC_TLV_ULTRA_STRING, NULL, str_len);
3121 
3122 	return buf;
3123 }
3124 
3125 #if 0
3126 int link_control(const char *name, u32 op, u32 val)
3127 {
3128 	int res = -EINVAL;
3129 	struct link *l_ptr;
3130 	u32 bearer_id;
3131 	struct node * node;
3132 	u32 a;
3133 
3134 	a = link_name2addr(name, &bearer_id);
3135 	read_lock_bh(&tipc_net_lock);
3136 	node = tipc_node_find(a);
3137 	if (node) {
3138 		tipc_node_lock(node);
3139 		l_ptr = node->links[bearer_id];
3140 		if (l_ptr) {
3141 			if (op == TIPC_REMOVE_LINK) {
3142 				struct bearer *b_ptr = l_ptr->b_ptr;
3143 				spin_lock_bh(&b_ptr->publ.lock);
3144 				tipc_link_delete(l_ptr);
3145 				spin_unlock_bh(&b_ptr->publ.lock);
3146 			}
3147 			if (op == TIPC_CMD_BLOCK_LINK) {
3148 				tipc_link_reset(l_ptr);
3149 				l_ptr->blocked = 1;
3150 			}
3151 			if (op == TIPC_CMD_UNBLOCK_LINK) {
3152 				l_ptr->blocked = 0;
3153 			}
3154 			res = TIPC_OK;
3155 		}
3156 		tipc_node_unlock(node);
3157 	}
3158 	read_unlock_bh(&tipc_net_lock);
3159 	return res;
3160 }
3161 #endif
3162 
3163 /**
3164  * tipc_link_get_max_pkt - get maximum packet size to use when sending to destination
3165  * @dest: network address of destination node
3166  * @selector: used to select from set of active links
3167  *
3168  * If no active link can be found, uses default maximum packet size.
3169  */
3170 
3171 u32 tipc_link_get_max_pkt(u32 dest, u32 selector)
3172 {
3173 	struct node *n_ptr;
3174 	struct link *l_ptr;
3175 	u32 res = MAX_PKT_DEFAULT;
3176 
3177 	if (dest == tipc_own_addr)
3178 		return MAX_MSG_SIZE;
3179 
3180 	read_lock_bh(&tipc_net_lock);
3181 	n_ptr = tipc_node_select(dest, selector);
3182 	if (n_ptr) {
3183 		tipc_node_lock(n_ptr);
3184 		l_ptr = n_ptr->active_links[selector & 1];
3185 		if (l_ptr)
3186 			res = link_max_pkt(l_ptr);
3187 		tipc_node_unlock(n_ptr);
3188 	}
3189 	read_unlock_bh(&tipc_net_lock);
3190 	return res;
3191 }
3192 
3193 #if 0
3194 static void link_dump_rec_queue(struct link *l_ptr)
3195 {
3196 	struct sk_buff *crs;
3197 
3198 	if (!l_ptr->oldest_deferred_in) {
3199 		info("Reception queue empty\n");
3200 		return;
3201 	}
3202 	info("Contents of Reception queue:\n");
3203 	crs = l_ptr->oldest_deferred_in;
3204 	while (crs) {
3205 		if (crs->data == (void *)0x0000a3a3) {
3206 			info("buffer %x invalid\n", crs);
3207 			return;
3208 		}
3209 		msg_dbg(buf_msg(crs), "In rec queue: \n");
3210 		crs = crs->next;
3211 	}
3212 }
3213 #endif
3214 
3215 static void link_dump_send_queue(struct link *l_ptr)
3216 {
3217 	if (l_ptr->next_out) {
3218 		info("\nContents of unsent queue:\n");
3219 		dbg_print_buf_chain(l_ptr->next_out);
3220 	}
3221 	info("\nContents of send queue:\n");
3222 	if (l_ptr->first_out) {
3223 		dbg_print_buf_chain(l_ptr->first_out);
3224 	}
3225 	info("Empty send queue\n");
3226 }
3227 
3228 static void link_print(struct link *l_ptr, struct print_buf *buf,
3229 		       const char *str)
3230 {
3231 	tipc_printf(buf, str);
3232 	if (link_reset_reset(l_ptr) || link_reset_unknown(l_ptr))
3233 		return;
3234 	tipc_printf(buf, "Link %x<%s>:",
3235 		    l_ptr->addr, l_ptr->b_ptr->publ.name);
3236 	tipc_printf(buf, ": NXO(%u):", mod(l_ptr->next_out_no));
3237 	tipc_printf(buf, "NXI(%u):", mod(l_ptr->next_in_no));
3238 	tipc_printf(buf, "SQUE");
3239 	if (l_ptr->first_out) {
3240 		tipc_printf(buf, "[%u..", msg_seqno(buf_msg(l_ptr->first_out)));
3241 		if (l_ptr->next_out)
3242 			tipc_printf(buf, "%u..",
3243 				    msg_seqno(buf_msg(l_ptr->next_out)));
3244 		tipc_printf(buf, "%u]",
3245 			    msg_seqno(buf_msg
3246 				      (l_ptr->last_out)), l_ptr->out_queue_size);
3247 		if ((mod(msg_seqno(buf_msg(l_ptr->last_out)) -
3248 			 msg_seqno(buf_msg(l_ptr->first_out)))
3249 		     != (l_ptr->out_queue_size - 1))
3250 		    || (l_ptr->last_out->next != 0)) {
3251 			tipc_printf(buf, "\nSend queue inconsistency\n");
3252 			tipc_printf(buf, "first_out= %x ", l_ptr->first_out);
3253 			tipc_printf(buf, "next_out= %x ", l_ptr->next_out);
3254 			tipc_printf(buf, "last_out= %x ", l_ptr->last_out);
3255 			link_dump_send_queue(l_ptr);
3256 		}
3257 	} else
3258 		tipc_printf(buf, "[]");
3259 	tipc_printf(buf, "SQSIZ(%u)", l_ptr->out_queue_size);
3260 	if (l_ptr->oldest_deferred_in) {
3261 		u32 o = msg_seqno(buf_msg(l_ptr->oldest_deferred_in));
3262 		u32 n = msg_seqno(buf_msg(l_ptr->newest_deferred_in));
3263 		tipc_printf(buf, ":RQUE[%u..%u]", o, n);
3264 		if (l_ptr->deferred_inqueue_sz != mod((n + 1) - o)) {
3265 			tipc_printf(buf, ":RQSIZ(%u)",
3266 				    l_ptr->deferred_inqueue_sz);
3267 		}
3268 	}
3269 	if (link_working_unknown(l_ptr))
3270 		tipc_printf(buf, ":WU");
3271 	if (link_reset_reset(l_ptr))
3272 		tipc_printf(buf, ":RR");
3273 	if (link_reset_unknown(l_ptr))
3274 		tipc_printf(buf, ":RU");
3275 	if (link_working_working(l_ptr))
3276 		tipc_printf(buf, ":WW");
3277 	tipc_printf(buf, "\n");
3278 }
3279 
3280