xref: /openbmc/linux/net/tipc/link.c (revision 64c70b1c)
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 (TIPC_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 TIPC_PB_MIN_SIZE
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 != TIPC_NULL)
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 != TIPC_NULL) {
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 = kzalloc(sizeof(*l_ptr), GFP_ATOMIC);
421 	if (!l_ptr) {
422 		warn("Link creation failed, no memory\n");
423 		return NULL;
424 	}
425 
426 	l_ptr->addr = peer;
427 	if_name = strchr(b_ptr->publ.name, ':') + 1;
428 	sprintf(l_ptr->name, "%u.%u.%u:%s-%u.%u.%u:",
429 		tipc_zone(tipc_own_addr), tipc_cluster(tipc_own_addr),
430 		tipc_node(tipc_own_addr),
431 		if_name,
432 		tipc_zone(peer), tipc_cluster(peer), tipc_node(peer));
433 		/* note: peer i/f is appended to link name by reset/activate */
434 	memcpy(&l_ptr->media_addr, media_addr, sizeof(*media_addr));
435 	k_init_timer(&l_ptr->timer, (Handler)link_timeout, (unsigned long)l_ptr);
436 	list_add_tail(&l_ptr->link_list, &b_ptr->links);
437 	l_ptr->checkpoint = 1;
438 	l_ptr->b_ptr = b_ptr;
439 	link_set_supervision_props(l_ptr, b_ptr->media->tolerance);
440 	l_ptr->state = RESET_UNKNOWN;
441 
442 	l_ptr->pmsg = (struct tipc_msg *)&l_ptr->proto_msg;
443 	msg = l_ptr->pmsg;
444 	msg_init(msg, LINK_PROTOCOL, RESET_MSG, TIPC_OK, INT_H_SIZE, l_ptr->addr);
445 	msg_set_size(msg, sizeof(l_ptr->proto_msg));
446 	msg_set_session(msg, tipc_random);
447 	msg_set_bearer_id(msg, b_ptr->identity);
448 	strcpy((char *)msg_data(msg), if_name);
449 
450 	l_ptr->priority = b_ptr->priority;
451 	tipc_link_set_queue_limits(l_ptr, b_ptr->media->window);
452 
453 	link_init_max_pkt(l_ptr);
454 
455 	l_ptr->next_out_no = 1;
456 	INIT_LIST_HEAD(&l_ptr->waiting_ports);
457 
458 	link_reset_statistics(l_ptr);
459 
460 	l_ptr->owner = tipc_node_attach_link(l_ptr);
461 	if (!l_ptr->owner) {
462 		kfree(l_ptr);
463 		return NULL;
464 	}
465 
466 	if (LINK_LOG_BUF_SIZE) {
467 		char *pb = kmalloc(LINK_LOG_BUF_SIZE, GFP_ATOMIC);
468 
469 		if (!pb) {
470 			kfree(l_ptr);
471 			warn("Link creation failed, no memory for print buffer\n");
472 			return NULL;
473 		}
474 		tipc_printbuf_init(&l_ptr->print_buf, pb, LINK_LOG_BUF_SIZE);
475 	}
476 
477 	tipc_k_signal((Handler)tipc_link_start, (unsigned long)l_ptr);
478 
479 	dbg("tipc_link_create(): tolerance = %u,cont intv = %u, abort_limit = %u\n",
480 	    l_ptr->tolerance, l_ptr->continuity_interval, l_ptr->abort_limit);
481 
482 	return l_ptr;
483 }
484 
485 /**
486  * tipc_link_delete - delete a link
487  * @l_ptr: pointer to link
488  *
489  * Note: 'tipc_net_lock' is write_locked, bearer is locked.
490  * This routine must not grab the node lock until after link timer cancellation
491  * to avoid a potential deadlock situation.
492  */
493 
494 void tipc_link_delete(struct link *l_ptr)
495 {
496 	if (!l_ptr) {
497 		err("Attempt to delete non-existent link\n");
498 		return;
499 	}
500 
501 	dbg("tipc_link_delete()\n");
502 
503 	k_cancel_timer(&l_ptr->timer);
504 
505 	tipc_node_lock(l_ptr->owner);
506 	tipc_link_reset(l_ptr);
507 	tipc_node_detach_link(l_ptr->owner, l_ptr);
508 	tipc_link_stop(l_ptr);
509 	list_del_init(&l_ptr->link_list);
510 	if (LINK_LOG_BUF_SIZE)
511 		kfree(l_ptr->print_buf.buf);
512 	tipc_node_unlock(l_ptr->owner);
513 	k_term_timer(&l_ptr->timer);
514 	kfree(l_ptr);
515 }
516 
517 void tipc_link_start(struct link *l_ptr)
518 {
519 	dbg("tipc_link_start %x\n", l_ptr);
520 	link_state_event(l_ptr, STARTING_EVT);
521 }
522 
523 /**
524  * link_schedule_port - schedule port for deferred sending
525  * @l_ptr: pointer to link
526  * @origport: reference to sending port
527  * @sz: amount of data to be sent
528  *
529  * Schedules port for renewed sending of messages after link congestion
530  * has abated.
531  */
532 
533 static int link_schedule_port(struct link *l_ptr, u32 origport, u32 sz)
534 {
535 	struct port *p_ptr;
536 
537 	spin_lock_bh(&tipc_port_list_lock);
538 	p_ptr = tipc_port_lock(origport);
539 	if (p_ptr) {
540 		if (!p_ptr->wakeup)
541 			goto exit;
542 		if (!list_empty(&p_ptr->wait_list))
543 			goto exit;
544 		p_ptr->congested_link = l_ptr;
545 		p_ptr->publ.congested = 1;
546 		p_ptr->waiting_pkts = 1 + ((sz - 1) / link_max_pkt(l_ptr));
547 		list_add_tail(&p_ptr->wait_list, &l_ptr->waiting_ports);
548 		l_ptr->stats.link_congs++;
549 exit:
550 		tipc_port_unlock(p_ptr);
551 	}
552 	spin_unlock_bh(&tipc_port_list_lock);
553 	return -ELINKCONG;
554 }
555 
556 void tipc_link_wakeup_ports(struct link *l_ptr, int all)
557 {
558 	struct port *p_ptr;
559 	struct port *temp_p_ptr;
560 	int win = l_ptr->queue_limit[0] - l_ptr->out_queue_size;
561 
562 	if (all)
563 		win = 100000;
564 	if (win <= 0)
565 		return;
566 	if (!spin_trylock_bh(&tipc_port_list_lock))
567 		return;
568 	if (link_congested(l_ptr))
569 		goto exit;
570 	list_for_each_entry_safe(p_ptr, temp_p_ptr, &l_ptr->waiting_ports,
571 				 wait_list) {
572 		if (win <= 0)
573 			break;
574 		list_del_init(&p_ptr->wait_list);
575 		p_ptr->congested_link = NULL;
576 		spin_lock_bh(p_ptr->publ.lock);
577 		p_ptr->publ.congested = 0;
578 		p_ptr->wakeup(&p_ptr->publ);
579 		win -= p_ptr->waiting_pkts;
580 		spin_unlock_bh(p_ptr->publ.lock);
581 	}
582 
583 exit:
584 	spin_unlock_bh(&tipc_port_list_lock);
585 }
586 
587 /**
588  * link_release_outqueue - purge link's outbound message queue
589  * @l_ptr: pointer to link
590  */
591 
592 static void link_release_outqueue(struct link *l_ptr)
593 {
594 	struct sk_buff *buf = l_ptr->first_out;
595 	struct sk_buff *next;
596 
597 	while (buf) {
598 		next = buf->next;
599 		buf_discard(buf);
600 		buf = next;
601 	}
602 	l_ptr->first_out = NULL;
603 	l_ptr->out_queue_size = 0;
604 }
605 
606 /**
607  * tipc_link_reset_fragments - purge link's inbound message fragments queue
608  * @l_ptr: pointer to link
609  */
610 
611 void tipc_link_reset_fragments(struct link *l_ptr)
612 {
613 	struct sk_buff *buf = l_ptr->defragm_buf;
614 	struct sk_buff *next;
615 
616 	while (buf) {
617 		next = buf->next;
618 		buf_discard(buf);
619 		buf = next;
620 	}
621 	l_ptr->defragm_buf = NULL;
622 }
623 
624 /**
625  * tipc_link_stop - purge all inbound and outbound messages associated with link
626  * @l_ptr: pointer to link
627  */
628 
629 void tipc_link_stop(struct link *l_ptr)
630 {
631 	struct sk_buff *buf;
632 	struct sk_buff *next;
633 
634 	buf = l_ptr->oldest_deferred_in;
635 	while (buf) {
636 		next = buf->next;
637 		buf_discard(buf);
638 		buf = next;
639 	}
640 
641 	buf = l_ptr->first_out;
642 	while (buf) {
643 		next = buf->next;
644 		buf_discard(buf);
645 		buf = next;
646 	}
647 
648 	tipc_link_reset_fragments(l_ptr);
649 
650 	buf_discard(l_ptr->proto_msg_queue);
651 	l_ptr->proto_msg_queue = NULL;
652 }
653 
654 #if 0
655 
656 /* LINK EVENT CODE IS NOT SUPPORTED AT PRESENT */
657 
658 static void link_recv_event(struct link_event *ev)
659 {
660 	ev->fcn(ev->addr, ev->name, ev->up);
661 	kfree(ev);
662 }
663 
664 static void link_send_event(void (*fcn)(u32 a, char *n, int up),
665 			    struct link *l_ptr, int up)
666 {
667 	struct link_event *ev;
668 
669 	ev = kmalloc(sizeof(*ev), GFP_ATOMIC);
670 	if (!ev) {
671 		warn("Link event allocation failure\n");
672 		return;
673 	}
674 	ev->addr = l_ptr->addr;
675 	ev->up = up;
676 	ev->fcn = fcn;
677 	memcpy(ev->name, l_ptr->name, TIPC_MAX_LINK_NAME);
678 	tipc_k_signal((Handler)link_recv_event, (unsigned long)ev);
679 }
680 
681 #else
682 
683 #define link_send_event(fcn, l_ptr, up) do { } while (0)
684 
685 #endif
686 
687 void tipc_link_reset(struct link *l_ptr)
688 {
689 	struct sk_buff *buf;
690 	u32 prev_state = l_ptr->state;
691 	u32 checkpoint = l_ptr->next_in_no;
692 	int was_active_link = tipc_link_is_active(l_ptr);
693 
694 	msg_set_session(l_ptr->pmsg, msg_session(l_ptr->pmsg) + 1);
695 
696 	/* Link is down, accept any session: */
697 	l_ptr->peer_session = 0;
698 
699 	/* Prepare for max packet size negotiation */
700 	link_init_max_pkt(l_ptr);
701 
702 	l_ptr->state = RESET_UNKNOWN;
703 	dbg_link_state("Resetting Link\n");
704 
705 	if ((prev_state == RESET_UNKNOWN) || (prev_state == RESET_RESET))
706 		return;
707 
708 	tipc_node_link_down(l_ptr->owner, l_ptr);
709 	tipc_bearer_remove_dest(l_ptr->b_ptr, l_ptr->addr);
710 #if 0
711 	tipc_printf(TIPC_CONS, "\nReset link <%s>\n", l_ptr->name);
712 	dbg_link_dump();
713 #endif
714 	if (was_active_link && tipc_node_has_active_links(l_ptr->owner) &&
715 	    l_ptr->owner->permit_changeover) {
716 		l_ptr->reset_checkpoint = checkpoint;
717 		l_ptr->exp_msg_count = START_CHANGEOVER;
718 	}
719 
720 	/* Clean up all queues: */
721 
722 	link_release_outqueue(l_ptr);
723 	buf_discard(l_ptr->proto_msg_queue);
724 	l_ptr->proto_msg_queue = NULL;
725 	buf = l_ptr->oldest_deferred_in;
726 	while (buf) {
727 		struct sk_buff *next = buf->next;
728 		buf_discard(buf);
729 		buf = next;
730 	}
731 	if (!list_empty(&l_ptr->waiting_ports))
732 		tipc_link_wakeup_ports(l_ptr, 1);
733 
734 	l_ptr->retransm_queue_head = 0;
735 	l_ptr->retransm_queue_size = 0;
736 	l_ptr->last_out = NULL;
737 	l_ptr->first_out = NULL;
738 	l_ptr->next_out = NULL;
739 	l_ptr->unacked_window = 0;
740 	l_ptr->checkpoint = 1;
741 	l_ptr->next_out_no = 1;
742 	l_ptr->deferred_inqueue_sz = 0;
743 	l_ptr->oldest_deferred_in = NULL;
744 	l_ptr->newest_deferred_in = NULL;
745 	l_ptr->fsm_msg_cnt = 0;
746 	l_ptr->stale_count = 0;
747 	link_reset_statistics(l_ptr);
748 
749 	link_send_event(tipc_cfg_link_event, l_ptr, 0);
750 	if (!in_own_cluster(l_ptr->addr))
751 		link_send_event(tipc_disc_link_event, l_ptr, 0);
752 }
753 
754 
755 static void link_activate(struct link *l_ptr)
756 {
757 	l_ptr->next_in_no = l_ptr->stats.recv_info = 1;
758 	tipc_node_link_up(l_ptr->owner, l_ptr);
759 	tipc_bearer_add_dest(l_ptr->b_ptr, l_ptr->addr);
760 	link_send_event(tipc_cfg_link_event, l_ptr, 1);
761 	if (!in_own_cluster(l_ptr->addr))
762 		link_send_event(tipc_disc_link_event, l_ptr, 1);
763 }
764 
765 /**
766  * link_state_event - link finite state machine
767  * @l_ptr: pointer to link
768  * @event: state machine event to process
769  */
770 
771 static void link_state_event(struct link *l_ptr, unsigned event)
772 {
773 	struct link *other;
774 	u32 cont_intv = l_ptr->continuity_interval;
775 
776 	if (!l_ptr->started && (event != STARTING_EVT))
777 		return;		/* Not yet. */
778 
779 	if (link_blocked(l_ptr)) {
780 		if (event == TIMEOUT_EVT) {
781 			link_set_timer(l_ptr, cont_intv);
782 		}
783 		return;	  /* Changeover going on */
784 	}
785 	dbg_link("STATE_EV: <%s> ", l_ptr->name);
786 
787 	switch (l_ptr->state) {
788 	case WORKING_WORKING:
789 		dbg_link("WW/");
790 		switch (event) {
791 		case TRAFFIC_MSG_EVT:
792 			dbg_link("TRF-");
793 			/* fall through */
794 		case ACTIVATE_MSG:
795 			dbg_link("ACT\n");
796 			break;
797 		case TIMEOUT_EVT:
798 			dbg_link("TIM ");
799 			if (l_ptr->next_in_no != l_ptr->checkpoint) {
800 				l_ptr->checkpoint = l_ptr->next_in_no;
801 				if (tipc_bclink_acks_missing(l_ptr->owner)) {
802 					tipc_link_send_proto_msg(l_ptr, STATE_MSG,
803 								 0, 0, 0, 0, 0);
804 					l_ptr->fsm_msg_cnt++;
805 				} else if (l_ptr->max_pkt < l_ptr->max_pkt_target) {
806 					tipc_link_send_proto_msg(l_ptr, STATE_MSG,
807 								 1, 0, 0, 0, 0);
808 					l_ptr->fsm_msg_cnt++;
809 				}
810 				link_set_timer(l_ptr, cont_intv);
811 				break;
812 			}
813 			dbg_link(" -> WU\n");
814 			l_ptr->state = WORKING_UNKNOWN;
815 			l_ptr->fsm_msg_cnt = 0;
816 			tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
817 			l_ptr->fsm_msg_cnt++;
818 			link_set_timer(l_ptr, cont_intv / 4);
819 			break;
820 		case RESET_MSG:
821 			dbg_link("RES -> RR\n");
822 			info("Resetting link <%s>, requested by peer\n",
823 			     l_ptr->name);
824 			tipc_link_reset(l_ptr);
825 			l_ptr->state = RESET_RESET;
826 			l_ptr->fsm_msg_cnt = 0;
827 			tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
828 			l_ptr->fsm_msg_cnt++;
829 			link_set_timer(l_ptr, cont_intv);
830 			break;
831 		default:
832 			err("Unknown link event %u in WW state\n", event);
833 		}
834 		break;
835 	case WORKING_UNKNOWN:
836 		dbg_link("WU/");
837 		switch (event) {
838 		case TRAFFIC_MSG_EVT:
839 			dbg_link("TRF-");
840 		case ACTIVATE_MSG:
841 			dbg_link("ACT -> WW\n");
842 			l_ptr->state = WORKING_WORKING;
843 			l_ptr->fsm_msg_cnt = 0;
844 			link_set_timer(l_ptr, cont_intv);
845 			break;
846 		case RESET_MSG:
847 			dbg_link("RES -> RR\n");
848 			info("Resetting link <%s>, requested by peer "
849 			     "while probing\n", l_ptr->name);
850 			tipc_link_reset(l_ptr);
851 			l_ptr->state = RESET_RESET;
852 			l_ptr->fsm_msg_cnt = 0;
853 			tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
854 			l_ptr->fsm_msg_cnt++;
855 			link_set_timer(l_ptr, cont_intv);
856 			break;
857 		case TIMEOUT_EVT:
858 			dbg_link("TIM ");
859 			if (l_ptr->next_in_no != l_ptr->checkpoint) {
860 				dbg_link("-> WW \n");
861 				l_ptr->state = WORKING_WORKING;
862 				l_ptr->fsm_msg_cnt = 0;
863 				l_ptr->checkpoint = l_ptr->next_in_no;
864 				if (tipc_bclink_acks_missing(l_ptr->owner)) {
865 					tipc_link_send_proto_msg(l_ptr, STATE_MSG,
866 								 0, 0, 0, 0, 0);
867 					l_ptr->fsm_msg_cnt++;
868 				}
869 				link_set_timer(l_ptr, cont_intv);
870 			} else if (l_ptr->fsm_msg_cnt < l_ptr->abort_limit) {
871 				dbg_link("Probing %u/%u,timer = %u ms)\n",
872 					 l_ptr->fsm_msg_cnt, l_ptr->abort_limit,
873 					 cont_intv / 4);
874 				tipc_link_send_proto_msg(l_ptr, STATE_MSG,
875 							 1, 0, 0, 0, 0);
876 				l_ptr->fsm_msg_cnt++;
877 				link_set_timer(l_ptr, cont_intv / 4);
878 			} else {	/* Link has failed */
879 				dbg_link("-> RU (%u probes unanswered)\n",
880 					 l_ptr->fsm_msg_cnt);
881 				warn("Resetting link <%s>, peer not responding\n",
882 				     l_ptr->name);
883 				tipc_link_reset(l_ptr);
884 				l_ptr->state = RESET_UNKNOWN;
885 				l_ptr->fsm_msg_cnt = 0;
886 				tipc_link_send_proto_msg(l_ptr, RESET_MSG,
887 							 0, 0, 0, 0, 0);
888 				l_ptr->fsm_msg_cnt++;
889 				link_set_timer(l_ptr, cont_intv);
890 			}
891 			break;
892 		default:
893 			err("Unknown link event %u in WU state\n", event);
894 		}
895 		break;
896 	case RESET_UNKNOWN:
897 		dbg_link("RU/");
898 		switch (event) {
899 		case TRAFFIC_MSG_EVT:
900 			dbg_link("TRF-\n");
901 			break;
902 		case ACTIVATE_MSG:
903 			other = l_ptr->owner->active_links[0];
904 			if (other && link_working_unknown(other)) {
905 				dbg_link("ACT\n");
906 				break;
907 			}
908 			dbg_link("ACT -> WW\n");
909 			l_ptr->state = WORKING_WORKING;
910 			l_ptr->fsm_msg_cnt = 0;
911 			link_activate(l_ptr);
912 			tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
913 			l_ptr->fsm_msg_cnt++;
914 			link_set_timer(l_ptr, cont_intv);
915 			break;
916 		case RESET_MSG:
917 			dbg_link("RES \n");
918 			dbg_link(" -> RR\n");
919 			l_ptr->state = RESET_RESET;
920 			l_ptr->fsm_msg_cnt = 0;
921 			tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 1, 0, 0, 0, 0);
922 			l_ptr->fsm_msg_cnt++;
923 			link_set_timer(l_ptr, cont_intv);
924 			break;
925 		case STARTING_EVT:
926 			dbg_link("START-");
927 			l_ptr->started = 1;
928 			/* fall through */
929 		case TIMEOUT_EVT:
930 			dbg_link("TIM \n");
931 			tipc_link_send_proto_msg(l_ptr, RESET_MSG, 0, 0, 0, 0, 0);
932 			l_ptr->fsm_msg_cnt++;
933 			link_set_timer(l_ptr, cont_intv);
934 			break;
935 		default:
936 			err("Unknown link event %u in RU state\n", event);
937 		}
938 		break;
939 	case RESET_RESET:
940 		dbg_link("RR/ ");
941 		switch (event) {
942 		case TRAFFIC_MSG_EVT:
943 			dbg_link("TRF-");
944 			/* fall through */
945 		case ACTIVATE_MSG:
946 			other = l_ptr->owner->active_links[0];
947 			if (other && link_working_unknown(other)) {
948 				dbg_link("ACT\n");
949 				break;
950 			}
951 			dbg_link("ACT -> WW\n");
952 			l_ptr->state = WORKING_WORKING;
953 			l_ptr->fsm_msg_cnt = 0;
954 			link_activate(l_ptr);
955 			tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
956 			l_ptr->fsm_msg_cnt++;
957 			link_set_timer(l_ptr, cont_intv);
958 			break;
959 		case RESET_MSG:
960 			dbg_link("RES\n");
961 			break;
962 		case TIMEOUT_EVT:
963 			dbg_link("TIM\n");
964 			tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
965 			l_ptr->fsm_msg_cnt++;
966 			link_set_timer(l_ptr, cont_intv);
967 			dbg_link("fsm_msg_cnt %u\n", l_ptr->fsm_msg_cnt);
968 			break;
969 		default:
970 			err("Unknown link event %u in RR state\n", event);
971 		}
972 		break;
973 	default:
974 		err("Unknown link state %u/%u\n", l_ptr->state, event);
975 	}
976 }
977 
978 /*
979  * link_bundle_buf(): Append contents of a buffer to
980  * the tail of an existing one.
981  */
982 
983 static int link_bundle_buf(struct link *l_ptr,
984 			   struct sk_buff *bundler,
985 			   struct sk_buff *buf)
986 {
987 	struct tipc_msg *bundler_msg = buf_msg(bundler);
988 	struct tipc_msg *msg = buf_msg(buf);
989 	u32 size = msg_size(msg);
990 	u32 bundle_size = msg_size(bundler_msg);
991 	u32 to_pos = align(bundle_size);
992 	u32 pad = to_pos - bundle_size;
993 
994 	if (msg_user(bundler_msg) != MSG_BUNDLER)
995 		return 0;
996 	if (msg_type(bundler_msg) != OPEN_MSG)
997 		return 0;
998 	if (skb_tailroom(bundler) < (pad + size))
999 		return 0;
1000 	if (link_max_pkt(l_ptr) < (to_pos + size))
1001 		return 0;
1002 
1003 	skb_put(bundler, pad + size);
1004 	skb_copy_to_linear_data_offset(bundler, to_pos, buf->data, size);
1005 	msg_set_size(bundler_msg, to_pos + size);
1006 	msg_set_msgcnt(bundler_msg, msg_msgcnt(bundler_msg) + 1);
1007 	dbg("Packed msg # %u(%u octets) into pos %u in buf(#%u)\n",
1008 	    msg_msgcnt(bundler_msg), size, to_pos, msg_seqno(bundler_msg));
1009 	msg_dbg(msg, "PACKD:");
1010 	buf_discard(buf);
1011 	l_ptr->stats.sent_bundled++;
1012 	return 1;
1013 }
1014 
1015 static void link_add_to_outqueue(struct link *l_ptr,
1016 				 struct sk_buff *buf,
1017 				 struct tipc_msg *msg)
1018 {
1019 	u32 ack = mod(l_ptr->next_in_no - 1);
1020 	u32 seqno = mod(l_ptr->next_out_no++);
1021 
1022 	msg_set_word(msg, 2, ((ack << 16) | seqno));
1023 	msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1024 	buf->next = NULL;
1025 	if (l_ptr->first_out) {
1026 		l_ptr->last_out->next = buf;
1027 		l_ptr->last_out = buf;
1028 	} else
1029 		l_ptr->first_out = l_ptr->last_out = buf;
1030 	l_ptr->out_queue_size++;
1031 }
1032 
1033 /*
1034  * tipc_link_send_buf() is the 'full path' for messages, called from
1035  * inside TIPC when the 'fast path' in tipc_send_buf
1036  * has failed, and from link_send()
1037  */
1038 
1039 int tipc_link_send_buf(struct link *l_ptr, struct sk_buff *buf)
1040 {
1041 	struct tipc_msg *msg = buf_msg(buf);
1042 	u32 size = msg_size(msg);
1043 	u32 dsz = msg_data_sz(msg);
1044 	u32 queue_size = l_ptr->out_queue_size;
1045 	u32 imp = msg_tot_importance(msg);
1046 	u32 queue_limit = l_ptr->queue_limit[imp];
1047 	u32 max_packet = link_max_pkt(l_ptr);
1048 
1049 	msg_set_prevnode(msg, tipc_own_addr);	/* If routed message */
1050 
1051 	/* Match msg importance against queue limits: */
1052 
1053 	if (unlikely(queue_size >= queue_limit)) {
1054 		if (imp <= TIPC_CRITICAL_IMPORTANCE) {
1055 			return link_schedule_port(l_ptr, msg_origport(msg),
1056 						  size);
1057 		}
1058 		msg_dbg(msg, "TIPC: Congestion, throwing away\n");
1059 		buf_discard(buf);
1060 		if (imp > CONN_MANAGER) {
1061 			warn("Resetting link <%s>, send queue full", l_ptr->name);
1062 			tipc_link_reset(l_ptr);
1063 		}
1064 		return dsz;
1065 	}
1066 
1067 	/* Fragmentation needed ? */
1068 
1069 	if (size > max_packet)
1070 		return tipc_link_send_long_buf(l_ptr, buf);
1071 
1072 	/* Packet can be queued or sent: */
1073 
1074 	if (queue_size > l_ptr->stats.max_queue_sz)
1075 		l_ptr->stats.max_queue_sz = queue_size;
1076 
1077 	if (likely(!tipc_bearer_congested(l_ptr->b_ptr, l_ptr) &&
1078 		   !link_congested(l_ptr))) {
1079 		link_add_to_outqueue(l_ptr, buf, msg);
1080 
1081 		if (likely(tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr))) {
1082 			l_ptr->unacked_window = 0;
1083 		} else {
1084 			tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
1085 			l_ptr->stats.bearer_congs++;
1086 			l_ptr->next_out = buf;
1087 		}
1088 		return dsz;
1089 	}
1090 	/* Congestion: can message be bundled ?: */
1091 
1092 	if ((msg_user(msg) != CHANGEOVER_PROTOCOL) &&
1093 	    (msg_user(msg) != MSG_FRAGMENTER)) {
1094 
1095 		/* Try adding message to an existing bundle */
1096 
1097 		if (l_ptr->next_out &&
1098 		    link_bundle_buf(l_ptr, l_ptr->last_out, buf)) {
1099 			tipc_bearer_resolve_congestion(l_ptr->b_ptr, l_ptr);
1100 			return dsz;
1101 		}
1102 
1103 		/* Try creating a new bundle */
1104 
1105 		if (size <= max_packet * 2 / 3) {
1106 			struct sk_buff *bundler = buf_acquire(max_packet);
1107 			struct tipc_msg bundler_hdr;
1108 
1109 			if (bundler) {
1110 				msg_init(&bundler_hdr, MSG_BUNDLER, OPEN_MSG,
1111 					 TIPC_OK, INT_H_SIZE, l_ptr->addr);
1112 				skb_copy_to_linear_data(bundler, &bundler_hdr,
1113 							INT_H_SIZE);
1114 				skb_trim(bundler, INT_H_SIZE);
1115 				link_bundle_buf(l_ptr, bundler, buf);
1116 				buf = bundler;
1117 				msg = buf_msg(buf);
1118 				l_ptr->stats.sent_bundles++;
1119 			}
1120 		}
1121 	}
1122 	if (!l_ptr->next_out)
1123 		l_ptr->next_out = buf;
1124 	link_add_to_outqueue(l_ptr, buf, msg);
1125 	tipc_bearer_resolve_congestion(l_ptr->b_ptr, l_ptr);
1126 	return dsz;
1127 }
1128 
1129 /*
1130  * tipc_link_send(): same as tipc_link_send_buf(), but the link to use has
1131  * not been selected yet, and the the owner node is not locked
1132  * Called by TIPC internal users, e.g. the name distributor
1133  */
1134 
1135 int tipc_link_send(struct sk_buff *buf, u32 dest, u32 selector)
1136 {
1137 	struct link *l_ptr;
1138 	struct node *n_ptr;
1139 	int res = -ELINKCONG;
1140 
1141 	read_lock_bh(&tipc_net_lock);
1142 	n_ptr = tipc_node_select(dest, selector);
1143 	if (n_ptr) {
1144 		tipc_node_lock(n_ptr);
1145 		l_ptr = n_ptr->active_links[selector & 1];
1146 		if (l_ptr) {
1147 			dbg("tipc_link_send: found link %x for dest %x\n", l_ptr, dest);
1148 			res = tipc_link_send_buf(l_ptr, buf);
1149 		} else {
1150 			dbg("Attempt to send msg to unreachable node:\n");
1151 			msg_dbg(buf_msg(buf),">>>");
1152 			buf_discard(buf);
1153 		}
1154 		tipc_node_unlock(n_ptr);
1155 	} else {
1156 		dbg("Attempt to send msg to unknown node:\n");
1157 		msg_dbg(buf_msg(buf),">>>");
1158 		buf_discard(buf);
1159 	}
1160 	read_unlock_bh(&tipc_net_lock);
1161 	return res;
1162 }
1163 
1164 /*
1165  * link_send_buf_fast: Entry for data messages where the
1166  * destination link is known and the header is complete,
1167  * inclusive total message length. Very time critical.
1168  * Link is locked. Returns user data length.
1169  */
1170 
1171 static int link_send_buf_fast(struct link *l_ptr, struct sk_buff *buf,
1172 			      u32 *used_max_pkt)
1173 {
1174 	struct tipc_msg *msg = buf_msg(buf);
1175 	int res = msg_data_sz(msg);
1176 
1177 	if (likely(!link_congested(l_ptr))) {
1178 		if (likely(msg_size(msg) <= link_max_pkt(l_ptr))) {
1179 			if (likely(list_empty(&l_ptr->b_ptr->cong_links))) {
1180 				link_add_to_outqueue(l_ptr, buf, msg);
1181 				if (likely(tipc_bearer_send(l_ptr->b_ptr, buf,
1182 							    &l_ptr->media_addr))) {
1183 					l_ptr->unacked_window = 0;
1184 					msg_dbg(msg,"SENT_FAST:");
1185 					return res;
1186 				}
1187 				dbg("failed sent fast...\n");
1188 				tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
1189 				l_ptr->stats.bearer_congs++;
1190 				l_ptr->next_out = buf;
1191 				return res;
1192 			}
1193 		}
1194 		else
1195 			*used_max_pkt = link_max_pkt(l_ptr);
1196 	}
1197 	return tipc_link_send_buf(l_ptr, buf);  /* All other cases */
1198 }
1199 
1200 /*
1201  * tipc_send_buf_fast: Entry for data messages where the
1202  * destination node is known and the header is complete,
1203  * inclusive total message length.
1204  * Returns user data length.
1205  */
1206 int tipc_send_buf_fast(struct sk_buff *buf, u32 destnode)
1207 {
1208 	struct link *l_ptr;
1209 	struct node *n_ptr;
1210 	int res;
1211 	u32 selector = msg_origport(buf_msg(buf)) & 1;
1212 	u32 dummy;
1213 
1214 	if (destnode == tipc_own_addr)
1215 		return tipc_port_recv_msg(buf);
1216 
1217 	read_lock_bh(&tipc_net_lock);
1218 	n_ptr = tipc_node_select(destnode, selector);
1219 	if (likely(n_ptr)) {
1220 		tipc_node_lock(n_ptr);
1221 		l_ptr = n_ptr->active_links[selector];
1222 		dbg("send_fast: buf %x selected %x, destnode = %x\n",
1223 		    buf, l_ptr, destnode);
1224 		if (likely(l_ptr)) {
1225 			res = link_send_buf_fast(l_ptr, buf, &dummy);
1226 			tipc_node_unlock(n_ptr);
1227 			read_unlock_bh(&tipc_net_lock);
1228 			return res;
1229 		}
1230 		tipc_node_unlock(n_ptr);
1231 	}
1232 	read_unlock_bh(&tipc_net_lock);
1233 	res = msg_data_sz(buf_msg(buf));
1234 	tipc_reject_msg(buf, TIPC_ERR_NO_NODE);
1235 	return res;
1236 }
1237 
1238 
1239 /*
1240  * tipc_link_send_sections_fast: Entry for messages where the
1241  * destination processor is known and the header is complete,
1242  * except for total message length.
1243  * Returns user data length or errno.
1244  */
1245 int tipc_link_send_sections_fast(struct port *sender,
1246 				 struct iovec const *msg_sect,
1247 				 const u32 num_sect,
1248 				 u32 destaddr)
1249 {
1250 	struct tipc_msg *hdr = &sender->publ.phdr;
1251 	struct link *l_ptr;
1252 	struct sk_buff *buf;
1253 	struct node *node;
1254 	int res;
1255 	u32 selector = msg_origport(hdr) & 1;
1256 
1257 again:
1258 	/*
1259 	 * Try building message using port's max_pkt hint.
1260 	 * (Must not hold any locks while building message.)
1261 	 */
1262 
1263 	res = msg_build(hdr, msg_sect, num_sect, sender->max_pkt,
1264 			!sender->user_port, &buf);
1265 
1266 	read_lock_bh(&tipc_net_lock);
1267 	node = tipc_node_select(destaddr, selector);
1268 	if (likely(node)) {
1269 		tipc_node_lock(node);
1270 		l_ptr = node->active_links[selector];
1271 		if (likely(l_ptr)) {
1272 			if (likely(buf)) {
1273 				res = link_send_buf_fast(l_ptr, buf,
1274 							 &sender->max_pkt);
1275 				if (unlikely(res < 0))
1276 					buf_discard(buf);
1277 exit:
1278 				tipc_node_unlock(node);
1279 				read_unlock_bh(&tipc_net_lock);
1280 				return res;
1281 			}
1282 
1283 			/* Exit if build request was invalid */
1284 
1285 			if (unlikely(res < 0))
1286 				goto exit;
1287 
1288 			/* Exit if link (or bearer) is congested */
1289 
1290 			if (link_congested(l_ptr) ||
1291 			    !list_empty(&l_ptr->b_ptr->cong_links)) {
1292 				res = link_schedule_port(l_ptr,
1293 							 sender->publ.ref, res);
1294 				goto exit;
1295 			}
1296 
1297 			/*
1298 			 * Message size exceeds max_pkt hint; update hint,
1299 			 * then re-try fast path or fragment the message
1300 			 */
1301 
1302 			sender->max_pkt = link_max_pkt(l_ptr);
1303 			tipc_node_unlock(node);
1304 			read_unlock_bh(&tipc_net_lock);
1305 
1306 
1307 			if ((msg_hdr_sz(hdr) + res) <= sender->max_pkt)
1308 				goto again;
1309 
1310 			return link_send_sections_long(sender, msg_sect,
1311 						       num_sect, destaddr);
1312 		}
1313 		tipc_node_unlock(node);
1314 	}
1315 	read_unlock_bh(&tipc_net_lock);
1316 
1317 	/* Couldn't find a link to the destination node */
1318 
1319 	if (buf)
1320 		return tipc_reject_msg(buf, TIPC_ERR_NO_NODE);
1321 	if (res >= 0)
1322 		return tipc_port_reject_sections(sender, hdr, msg_sect, num_sect,
1323 						 TIPC_ERR_NO_NODE);
1324 	return res;
1325 }
1326 
1327 /*
1328  * link_send_sections_long(): Entry for long messages where the
1329  * destination node is known and the header is complete,
1330  * inclusive total message length.
1331  * Link and bearer congestion status have been checked to be ok,
1332  * and are ignored if they change.
1333  *
1334  * Note that fragments do not use the full link MTU so that they won't have
1335  * to undergo refragmentation if link changeover causes them to be sent
1336  * over another link with an additional tunnel header added as prefix.
1337  * (Refragmentation will still occur if the other link has a smaller MTU.)
1338  *
1339  * Returns user data length or errno.
1340  */
1341 static int link_send_sections_long(struct port *sender,
1342 				   struct iovec const *msg_sect,
1343 				   u32 num_sect,
1344 				   u32 destaddr)
1345 {
1346 	struct link *l_ptr;
1347 	struct node *node;
1348 	struct tipc_msg *hdr = &sender->publ.phdr;
1349 	u32 dsz = msg_data_sz(hdr);
1350 	u32 max_pkt,fragm_sz,rest;
1351 	struct tipc_msg fragm_hdr;
1352 	struct sk_buff *buf,*buf_chain,*prev;
1353 	u32 fragm_crs,fragm_rest,hsz,sect_rest;
1354 	const unchar *sect_crs;
1355 	int curr_sect;
1356 	u32 fragm_no;
1357 
1358 again:
1359 	fragm_no = 1;
1360 	max_pkt = sender->max_pkt - INT_H_SIZE;
1361 		/* leave room for tunnel header in case of link changeover */
1362 	fragm_sz = max_pkt - INT_H_SIZE;
1363 		/* leave room for fragmentation header in each fragment */
1364 	rest = dsz;
1365 	fragm_crs = 0;
1366 	fragm_rest = 0;
1367 	sect_rest = 0;
1368 	sect_crs = NULL;
1369 	curr_sect = -1;
1370 
1371 	/* Prepare reusable fragment header: */
1372 
1373 	msg_dbg(hdr, ">FRAGMENTING>");
1374 	msg_init(&fragm_hdr, MSG_FRAGMENTER, FIRST_FRAGMENT,
1375 		 TIPC_OK, INT_H_SIZE, msg_destnode(hdr));
1376 	msg_set_link_selector(&fragm_hdr, sender->publ.ref);
1377 	msg_set_size(&fragm_hdr, max_pkt);
1378 	msg_set_fragm_no(&fragm_hdr, 1);
1379 
1380 	/* Prepare header of first fragment: */
1381 
1382 	buf_chain = buf = buf_acquire(max_pkt);
1383 	if (!buf)
1384 		return -ENOMEM;
1385 	buf->next = NULL;
1386 	skb_copy_to_linear_data(buf, &fragm_hdr, INT_H_SIZE);
1387 	hsz = msg_hdr_sz(hdr);
1388 	skb_copy_to_linear_data_offset(buf, INT_H_SIZE, hdr, hsz);
1389 	msg_dbg(buf_msg(buf), ">BUILD>");
1390 
1391 	/* Chop up message: */
1392 
1393 	fragm_crs = INT_H_SIZE + hsz;
1394 	fragm_rest = fragm_sz - hsz;
1395 
1396 	do {		/* For all sections */
1397 		u32 sz;
1398 
1399 		if (!sect_rest) {
1400 			sect_rest = msg_sect[++curr_sect].iov_len;
1401 			sect_crs = (const unchar *)msg_sect[curr_sect].iov_base;
1402 		}
1403 
1404 		if (sect_rest < fragm_rest)
1405 			sz = sect_rest;
1406 		else
1407 			sz = fragm_rest;
1408 
1409 		if (likely(!sender->user_port)) {
1410 			if (copy_from_user(buf->data + fragm_crs, sect_crs, sz)) {
1411 error:
1412 				for (; buf_chain; buf_chain = buf) {
1413 					buf = buf_chain->next;
1414 					buf_discard(buf_chain);
1415 				}
1416 				return -EFAULT;
1417 			}
1418 		} else
1419 			skb_copy_to_linear_data_offset(buf, fragm_crs,
1420 						       sect_crs, sz);
1421 		sect_crs += sz;
1422 		sect_rest -= sz;
1423 		fragm_crs += sz;
1424 		fragm_rest -= sz;
1425 		rest -= sz;
1426 
1427 		if (!fragm_rest && rest) {
1428 
1429 			/* Initiate new fragment: */
1430 			if (rest <= fragm_sz) {
1431 				fragm_sz = rest;
1432 				msg_set_type(&fragm_hdr,LAST_FRAGMENT);
1433 			} else {
1434 				msg_set_type(&fragm_hdr, FRAGMENT);
1435 			}
1436 			msg_set_size(&fragm_hdr, fragm_sz + INT_H_SIZE);
1437 			msg_set_fragm_no(&fragm_hdr, ++fragm_no);
1438 			prev = buf;
1439 			buf = buf_acquire(fragm_sz + INT_H_SIZE);
1440 			if (!buf)
1441 				goto error;
1442 
1443 			buf->next = NULL;
1444 			prev->next = buf;
1445 			skb_copy_to_linear_data(buf, &fragm_hdr, INT_H_SIZE);
1446 			fragm_crs = INT_H_SIZE;
1447 			fragm_rest = fragm_sz;
1448 			msg_dbg(buf_msg(buf),"  >BUILD>");
1449 		}
1450 	}
1451 	while (rest > 0);
1452 
1453 	/*
1454 	 * Now we have a buffer chain. Select a link and check
1455 	 * that packet size is still OK
1456 	 */
1457 	node = tipc_node_select(destaddr, sender->publ.ref & 1);
1458 	if (likely(node)) {
1459 		tipc_node_lock(node);
1460 		l_ptr = node->active_links[sender->publ.ref & 1];
1461 		if (!l_ptr) {
1462 			tipc_node_unlock(node);
1463 			goto reject;
1464 		}
1465 		if (link_max_pkt(l_ptr) < max_pkt) {
1466 			sender->max_pkt = link_max_pkt(l_ptr);
1467 			tipc_node_unlock(node);
1468 			for (; buf_chain; buf_chain = buf) {
1469 				buf = buf_chain->next;
1470 				buf_discard(buf_chain);
1471 			}
1472 			goto again;
1473 		}
1474 	} else {
1475 reject:
1476 		for (; buf_chain; buf_chain = buf) {
1477 			buf = buf_chain->next;
1478 			buf_discard(buf_chain);
1479 		}
1480 		return tipc_port_reject_sections(sender, hdr, msg_sect, num_sect,
1481 						 TIPC_ERR_NO_NODE);
1482 	}
1483 
1484 	/* Append whole chain to send queue: */
1485 
1486 	buf = buf_chain;
1487 	l_ptr->long_msg_seq_no = mod(l_ptr->long_msg_seq_no + 1);
1488 	if (!l_ptr->next_out)
1489 		l_ptr->next_out = buf_chain;
1490 	l_ptr->stats.sent_fragmented++;
1491 	while (buf) {
1492 		struct sk_buff *next = buf->next;
1493 		struct tipc_msg *msg = buf_msg(buf);
1494 
1495 		l_ptr->stats.sent_fragments++;
1496 		msg_set_long_msgno(msg, l_ptr->long_msg_seq_no);
1497 		link_add_to_outqueue(l_ptr, buf, msg);
1498 		msg_dbg(msg, ">ADD>");
1499 		buf = next;
1500 	}
1501 
1502 	/* Send it, if possible: */
1503 
1504 	tipc_link_push_queue(l_ptr);
1505 	tipc_node_unlock(node);
1506 	return dsz;
1507 }
1508 
1509 /*
1510  * tipc_link_push_packet: Push one unsent packet to the media
1511  */
1512 u32 tipc_link_push_packet(struct link *l_ptr)
1513 {
1514 	struct sk_buff *buf = l_ptr->first_out;
1515 	u32 r_q_size = l_ptr->retransm_queue_size;
1516 	u32 r_q_head = l_ptr->retransm_queue_head;
1517 
1518 	/* Step to position where retransmission failed, if any,    */
1519 	/* consider that buffers may have been released in meantime */
1520 
1521 	if (r_q_size && buf) {
1522 		u32 last = lesser(mod(r_q_head + r_q_size),
1523 				  link_last_sent(l_ptr));
1524 		u32 first = msg_seqno(buf_msg(buf));
1525 
1526 		while (buf && less(first, r_q_head)) {
1527 			first = mod(first + 1);
1528 			buf = buf->next;
1529 		}
1530 		l_ptr->retransm_queue_head = r_q_head = first;
1531 		l_ptr->retransm_queue_size = r_q_size = mod(last - first);
1532 	}
1533 
1534 	/* Continue retransmission now, if there is anything: */
1535 
1536 	if (r_q_size && buf && !skb_cloned(buf)) {
1537 		msg_set_ack(buf_msg(buf), mod(l_ptr->next_in_no - 1));
1538 		msg_set_bcast_ack(buf_msg(buf), l_ptr->owner->bclink.last_in);
1539 		if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1540 			msg_dbg(buf_msg(buf), ">DEF-RETR>");
1541 			l_ptr->retransm_queue_head = mod(++r_q_head);
1542 			l_ptr->retransm_queue_size = --r_q_size;
1543 			l_ptr->stats.retransmitted++;
1544 			return TIPC_OK;
1545 		} else {
1546 			l_ptr->stats.bearer_congs++;
1547 			msg_dbg(buf_msg(buf), "|>DEF-RETR>");
1548 			return PUSH_FAILED;
1549 		}
1550 	}
1551 
1552 	/* Send deferred protocol message, if any: */
1553 
1554 	buf = l_ptr->proto_msg_queue;
1555 	if (buf) {
1556 		msg_set_ack(buf_msg(buf), mod(l_ptr->next_in_no - 1));
1557 		msg_set_bcast_ack(buf_msg(buf),l_ptr->owner->bclink.last_in);
1558 		if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1559 			msg_dbg(buf_msg(buf), ">DEF-PROT>");
1560 			l_ptr->unacked_window = 0;
1561 			buf_discard(buf);
1562 			l_ptr->proto_msg_queue = NULL;
1563 			return TIPC_OK;
1564 		} else {
1565 			msg_dbg(buf_msg(buf), "|>DEF-PROT>");
1566 			l_ptr->stats.bearer_congs++;
1567 			return PUSH_FAILED;
1568 		}
1569 	}
1570 
1571 	/* Send one deferred data message, if send window not full: */
1572 
1573 	buf = l_ptr->next_out;
1574 	if (buf) {
1575 		struct tipc_msg *msg = buf_msg(buf);
1576 		u32 next = msg_seqno(msg);
1577 		u32 first = msg_seqno(buf_msg(l_ptr->first_out));
1578 
1579 		if (mod(next - first) < l_ptr->queue_limit[0]) {
1580 			msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1581 			msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1582 			if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1583 				if (msg_user(msg) == MSG_BUNDLER)
1584 					msg_set_type(msg, CLOSED_MSG);
1585 				msg_dbg(msg, ">PUSH-DATA>");
1586 				l_ptr->next_out = buf->next;
1587 				return TIPC_OK;
1588 			} else {
1589 				msg_dbg(msg, "|PUSH-DATA|");
1590 				l_ptr->stats.bearer_congs++;
1591 				return PUSH_FAILED;
1592 			}
1593 		}
1594 	}
1595 	return PUSH_FINISHED;
1596 }
1597 
1598 /*
1599  * push_queue(): push out the unsent messages of a link where
1600  *               congestion has abated. Node is locked
1601  */
1602 void tipc_link_push_queue(struct link *l_ptr)
1603 {
1604 	u32 res;
1605 
1606 	if (tipc_bearer_congested(l_ptr->b_ptr, l_ptr))
1607 		return;
1608 
1609 	do {
1610 		res = tipc_link_push_packet(l_ptr);
1611 	}
1612 	while (res == TIPC_OK);
1613 	if (res == PUSH_FAILED)
1614 		tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
1615 }
1616 
1617 static void link_reset_all(unsigned long addr)
1618 {
1619 	struct node *n_ptr;
1620 	char addr_string[16];
1621 	u32 i;
1622 
1623 	read_lock_bh(&tipc_net_lock);
1624 	n_ptr = tipc_node_find((u32)addr);
1625 	if (!n_ptr) {
1626 		read_unlock_bh(&tipc_net_lock);
1627 		return;	/* node no longer exists */
1628 	}
1629 
1630 	tipc_node_lock(n_ptr);
1631 
1632 	warn("Resetting all links to %s\n",
1633 	     addr_string_fill(addr_string, n_ptr->addr));
1634 
1635 	for (i = 0; i < MAX_BEARERS; i++) {
1636 		if (n_ptr->links[i]) {
1637 			link_print(n_ptr->links[i], TIPC_OUTPUT,
1638 				   "Resetting link\n");
1639 			tipc_link_reset(n_ptr->links[i]);
1640 		}
1641 	}
1642 
1643 	tipc_node_unlock(n_ptr);
1644 	read_unlock_bh(&tipc_net_lock);
1645 }
1646 
1647 static void link_retransmit_failure(struct link *l_ptr, struct sk_buff *buf)
1648 {
1649 	struct tipc_msg *msg = buf_msg(buf);
1650 
1651 	warn("Retransmission failure on link <%s>\n", l_ptr->name);
1652 	tipc_msg_print(TIPC_OUTPUT, msg, ">RETR-FAIL>");
1653 
1654 	if (l_ptr->addr) {
1655 
1656 		/* Handle failure on standard link */
1657 
1658 		link_print(l_ptr, TIPC_OUTPUT, "Resetting link\n");
1659 		tipc_link_reset(l_ptr);
1660 
1661 	} else {
1662 
1663 		/* Handle failure on broadcast link */
1664 
1665 		struct node *n_ptr;
1666 		char addr_string[16];
1667 
1668 		tipc_printf(TIPC_OUTPUT, "Msg seq number: %u,  ", msg_seqno(msg));
1669 		tipc_printf(TIPC_OUTPUT, "Outstanding acks: %lu\n",
1670 				     (unsigned long) 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 		skb_copy_to_linear_data(buf, 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 	skb_copy_to_linear_data(buf, 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 	skb_copy_to_linear_data(buf, tunnel_hdr, INT_H_SIZE);
2323 	skb_copy_to_linear_data_offset(buf, INT_H_SIZE, 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 			skb_copy_to_linear_data(buf, &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 		skb_copy_to_linear_data(outbuf, &tunnel_hdr, INT_H_SIZE);
2430 		skb_copy_to_linear_data_offset(outbuf, INT_H_SIZE, iter->data,
2431 					       length);
2432 		dbg("%c->%c:", l_ptr->b_ptr->net_plane,
2433 		    tunnel->b_ptr->net_plane);
2434 		msg_dbg(buf_msg(outbuf), ">SEND>");
2435 		tipc_link_send_buf(tunnel, outbuf);
2436 		if (!tipc_link_is_up(l_ptr))
2437 			return;
2438 		iter = iter->next;
2439 	}
2440 }
2441 
2442 
2443 
2444 /**
2445  * buf_extract - extracts embedded TIPC message from another message
2446  * @skb: encapsulating message buffer
2447  * @from_pos: offset to extract from
2448  *
2449  * Returns a new message buffer containing an embedded message.  The
2450  * encapsulating message itself is left unchanged.
2451  */
2452 
2453 static struct sk_buff *buf_extract(struct sk_buff *skb, u32 from_pos)
2454 {
2455 	struct tipc_msg *msg = (struct tipc_msg *)(skb->data + from_pos);
2456 	u32 size = msg_size(msg);
2457 	struct sk_buff *eb;
2458 
2459 	eb = buf_acquire(size);
2460 	if (eb)
2461 		skb_copy_to_linear_data(eb, msg, size);
2462 	return eb;
2463 }
2464 
2465 /*
2466  *  link_recv_changeover_msg(): Receive tunneled packet sent
2467  *  via other link. Node is locked. Return extracted buffer.
2468  */
2469 
2470 static int link_recv_changeover_msg(struct link **l_ptr,
2471 				    struct sk_buff **buf)
2472 {
2473 	struct sk_buff *tunnel_buf = *buf;
2474 	struct link *dest_link;
2475 	struct tipc_msg *msg;
2476 	struct tipc_msg *tunnel_msg = buf_msg(tunnel_buf);
2477 	u32 msg_typ = msg_type(tunnel_msg);
2478 	u32 msg_count = msg_msgcnt(tunnel_msg);
2479 
2480 	dest_link = (*l_ptr)->owner->links[msg_bearer_id(tunnel_msg)];
2481 	if (!dest_link) {
2482 		msg_dbg(tunnel_msg, "NOLINK/<REC<");
2483 		goto exit;
2484 	}
2485 	if (dest_link == *l_ptr) {
2486 		err("Unexpected changeover message on link <%s>\n",
2487 		    (*l_ptr)->name);
2488 		goto exit;
2489 	}
2490 	dbg("%c<-%c:", dest_link->b_ptr->net_plane,
2491 	    (*l_ptr)->b_ptr->net_plane);
2492 	*l_ptr = dest_link;
2493 	msg = msg_get_wrapped(tunnel_msg);
2494 
2495 	if (msg_typ == DUPLICATE_MSG) {
2496 		if (less(msg_seqno(msg), mod(dest_link->next_in_no))) {
2497 			msg_dbg(tunnel_msg, "DROP/<REC<");
2498 			goto exit;
2499 		}
2500 		*buf = buf_extract(tunnel_buf,INT_H_SIZE);
2501 		if (*buf == NULL) {
2502 			warn("Link changeover error, duplicate msg dropped\n");
2503 			goto exit;
2504 		}
2505 		msg_dbg(tunnel_msg, "TNL<REC<");
2506 		buf_discard(tunnel_buf);
2507 		return 1;
2508 	}
2509 
2510 	/* First original message ?: */
2511 
2512 	if (tipc_link_is_up(dest_link)) {
2513 		msg_dbg(tunnel_msg, "UP/FIRST/<REC<");
2514 		info("Resetting link <%s>, changeover initiated by peer\n",
2515 		     dest_link->name);
2516 		tipc_link_reset(dest_link);
2517 		dest_link->exp_msg_count = msg_count;
2518 		dbg("Expecting %u tunnelled messages\n", msg_count);
2519 		if (!msg_count)
2520 			goto exit;
2521 	} else if (dest_link->exp_msg_count == START_CHANGEOVER) {
2522 		msg_dbg(tunnel_msg, "BLK/FIRST/<REC<");
2523 		dest_link->exp_msg_count = msg_count;
2524 		dbg("Expecting %u tunnelled messages\n", msg_count);
2525 		if (!msg_count)
2526 			goto exit;
2527 	}
2528 
2529 	/* Receive original message */
2530 
2531 	if (dest_link->exp_msg_count == 0) {
2532 		warn("Link switchover error, "
2533 		     "got too many tunnelled messages\n");
2534 		msg_dbg(tunnel_msg, "OVERDUE/DROP/<REC<");
2535 		dbg_print_link(dest_link, "LINK:");
2536 		goto exit;
2537 	}
2538 	dest_link->exp_msg_count--;
2539 	if (less(msg_seqno(msg), dest_link->reset_checkpoint)) {
2540 		msg_dbg(tunnel_msg, "DROP/DUPL/<REC<");
2541 		goto exit;
2542 	} else {
2543 		*buf = buf_extract(tunnel_buf, INT_H_SIZE);
2544 		if (*buf != NULL) {
2545 			msg_dbg(tunnel_msg, "TNL<REC<");
2546 			buf_discard(tunnel_buf);
2547 			return 1;
2548 		} else {
2549 			warn("Link changeover error, original msg dropped\n");
2550 		}
2551 	}
2552 exit:
2553 	*buf = NULL;
2554 	buf_discard(tunnel_buf);
2555 	return 0;
2556 }
2557 
2558 /*
2559  *  Bundler functionality:
2560  */
2561 void tipc_link_recv_bundle(struct sk_buff *buf)
2562 {
2563 	u32 msgcount = msg_msgcnt(buf_msg(buf));
2564 	u32 pos = INT_H_SIZE;
2565 	struct sk_buff *obuf;
2566 
2567 	msg_dbg(buf_msg(buf), "<BNDL<: ");
2568 	while (msgcount--) {
2569 		obuf = buf_extract(buf, pos);
2570 		if (obuf == NULL) {
2571 			warn("Link unable to unbundle message(s)\n");
2572 			break;
2573 		}
2574 		pos += align(msg_size(buf_msg(obuf)));
2575 		msg_dbg(buf_msg(obuf), "     /");
2576 		tipc_net_route_msg(obuf);
2577 	}
2578 	buf_discard(buf);
2579 }
2580 
2581 /*
2582  *  Fragmentation/defragmentation:
2583  */
2584 
2585 
2586 /*
2587  * tipc_link_send_long_buf: Entry for buffers needing fragmentation.
2588  * The buffer is complete, inclusive total message length.
2589  * Returns user data length.
2590  */
2591 int tipc_link_send_long_buf(struct link *l_ptr, struct sk_buff *buf)
2592 {
2593 	struct tipc_msg *inmsg = buf_msg(buf);
2594 	struct tipc_msg fragm_hdr;
2595 	u32 insize = msg_size(inmsg);
2596 	u32 dsz = msg_data_sz(inmsg);
2597 	unchar *crs = buf->data;
2598 	u32 rest = insize;
2599 	u32 pack_sz = link_max_pkt(l_ptr);
2600 	u32 fragm_sz = pack_sz - INT_H_SIZE;
2601 	u32 fragm_no = 1;
2602 	u32 destaddr = msg_destnode(inmsg);
2603 
2604 	if (msg_short(inmsg))
2605 		destaddr = l_ptr->addr;
2606 
2607 	if (msg_routed(inmsg))
2608 		msg_set_prevnode(inmsg, tipc_own_addr);
2609 
2610 	/* Prepare reusable fragment header: */
2611 
2612 	msg_init(&fragm_hdr, MSG_FRAGMENTER, FIRST_FRAGMENT,
2613 		 TIPC_OK, INT_H_SIZE, destaddr);
2614 	msg_set_link_selector(&fragm_hdr, msg_link_selector(inmsg));
2615 	msg_set_long_msgno(&fragm_hdr, mod(l_ptr->long_msg_seq_no++));
2616 	msg_set_fragm_no(&fragm_hdr, fragm_no);
2617 	l_ptr->stats.sent_fragmented++;
2618 
2619 	/* Chop up message: */
2620 
2621 	while (rest > 0) {
2622 		struct sk_buff *fragm;
2623 
2624 		if (rest <= fragm_sz) {
2625 			fragm_sz = rest;
2626 			msg_set_type(&fragm_hdr, LAST_FRAGMENT);
2627 		}
2628 		fragm = buf_acquire(fragm_sz + INT_H_SIZE);
2629 		if (fragm == NULL) {
2630 			warn("Link unable to fragment message\n");
2631 			dsz = -ENOMEM;
2632 			goto exit;
2633 		}
2634 		msg_set_size(&fragm_hdr, fragm_sz + INT_H_SIZE);
2635 		skb_copy_to_linear_data(fragm, &fragm_hdr, INT_H_SIZE);
2636 		skb_copy_to_linear_data_offset(fragm, INT_H_SIZE, crs,
2637 					       fragm_sz);
2638 		/*  Send queued messages first, if any: */
2639 
2640 		l_ptr->stats.sent_fragments++;
2641 		tipc_link_send_buf(l_ptr, fragm);
2642 		if (!tipc_link_is_up(l_ptr))
2643 			return dsz;
2644 		msg_set_fragm_no(&fragm_hdr, ++fragm_no);
2645 		rest -= fragm_sz;
2646 		crs += fragm_sz;
2647 		msg_set_type(&fragm_hdr, FRAGMENT);
2648 	}
2649 exit:
2650 	buf_discard(buf);
2651 	return dsz;
2652 }
2653 
2654 /*
2655  * A pending message being re-assembled must store certain values
2656  * to handle subsequent fragments correctly. The following functions
2657  * help storing these values in unused, available fields in the
2658  * pending message. This makes dynamic memory allocation unecessary.
2659  */
2660 
2661 static void set_long_msg_seqno(struct sk_buff *buf, u32 seqno)
2662 {
2663 	msg_set_seqno(buf_msg(buf), seqno);
2664 }
2665 
2666 static u32 get_fragm_size(struct sk_buff *buf)
2667 {
2668 	return msg_ack(buf_msg(buf));
2669 }
2670 
2671 static void set_fragm_size(struct sk_buff *buf, u32 sz)
2672 {
2673 	msg_set_ack(buf_msg(buf), sz);
2674 }
2675 
2676 static u32 get_expected_frags(struct sk_buff *buf)
2677 {
2678 	return msg_bcast_ack(buf_msg(buf));
2679 }
2680 
2681 static void set_expected_frags(struct sk_buff *buf, u32 exp)
2682 {
2683 	msg_set_bcast_ack(buf_msg(buf), exp);
2684 }
2685 
2686 static u32 get_timer_cnt(struct sk_buff *buf)
2687 {
2688 	return msg_reroute_cnt(buf_msg(buf));
2689 }
2690 
2691 static void incr_timer_cnt(struct sk_buff *buf)
2692 {
2693 	msg_incr_reroute_cnt(buf_msg(buf));
2694 }
2695 
2696 /*
2697  * tipc_link_recv_fragment(): Called with node lock on. Returns
2698  * the reassembled buffer if message is complete.
2699  */
2700 int tipc_link_recv_fragment(struct sk_buff **pending, struct sk_buff **fb,
2701 			    struct tipc_msg **m)
2702 {
2703 	struct sk_buff *prev = NULL;
2704 	struct sk_buff *fbuf = *fb;
2705 	struct tipc_msg *fragm = buf_msg(fbuf);
2706 	struct sk_buff *pbuf = *pending;
2707 	u32 long_msg_seq_no = msg_long_msgno(fragm);
2708 
2709 	*fb = NULL;
2710 	msg_dbg(fragm,"FRG<REC<");
2711 
2712 	/* Is there an incomplete message waiting for this fragment? */
2713 
2714 	while (pbuf && ((msg_seqno(buf_msg(pbuf)) != long_msg_seq_no)
2715 			|| (msg_orignode(fragm) != msg_orignode(buf_msg(pbuf))))) {
2716 		prev = pbuf;
2717 		pbuf = pbuf->next;
2718 	}
2719 
2720 	if (!pbuf && (msg_type(fragm) == FIRST_FRAGMENT)) {
2721 		struct tipc_msg *imsg = (struct tipc_msg *)msg_data(fragm);
2722 		u32 msg_sz = msg_size(imsg);
2723 		u32 fragm_sz = msg_data_sz(fragm);
2724 		u32 exp_fragm_cnt = msg_sz/fragm_sz + !!(msg_sz % fragm_sz);
2725 		u32 max =  TIPC_MAX_USER_MSG_SIZE + LONG_H_SIZE;
2726 		if (msg_type(imsg) == TIPC_MCAST_MSG)
2727 			max = TIPC_MAX_USER_MSG_SIZE + MCAST_H_SIZE;
2728 		if (msg_size(imsg) > max) {
2729 			msg_dbg(fragm,"<REC<Oversized: ");
2730 			buf_discard(fbuf);
2731 			return 0;
2732 		}
2733 		pbuf = buf_acquire(msg_size(imsg));
2734 		if (pbuf != NULL) {
2735 			pbuf->next = *pending;
2736 			*pending = pbuf;
2737 			skb_copy_to_linear_data(pbuf, imsg,
2738 						msg_data_sz(fragm));
2739 			/*  Prepare buffer for subsequent fragments. */
2740 
2741 			set_long_msg_seqno(pbuf, long_msg_seq_no);
2742 			set_fragm_size(pbuf,fragm_sz);
2743 			set_expected_frags(pbuf,exp_fragm_cnt - 1);
2744 		} else {
2745 			warn("Link unable to reassemble fragmented message\n");
2746 		}
2747 		buf_discard(fbuf);
2748 		return 0;
2749 	} else if (pbuf && (msg_type(fragm) != FIRST_FRAGMENT)) {
2750 		u32 dsz = msg_data_sz(fragm);
2751 		u32 fsz = get_fragm_size(pbuf);
2752 		u32 crs = ((msg_fragm_no(fragm) - 1) * fsz);
2753 		u32 exp_frags = get_expected_frags(pbuf) - 1;
2754 		skb_copy_to_linear_data_offset(pbuf, crs,
2755 					       msg_data(fragm), dsz);
2756 		buf_discard(fbuf);
2757 
2758 		/* Is message complete? */
2759 
2760 		if (exp_frags == 0) {
2761 			if (prev)
2762 				prev->next = pbuf->next;
2763 			else
2764 				*pending = pbuf->next;
2765 			msg_reset_reroute_cnt(buf_msg(pbuf));
2766 			*fb = pbuf;
2767 			*m = buf_msg(pbuf);
2768 			return 1;
2769 		}
2770 		set_expected_frags(pbuf,exp_frags);
2771 		return 0;
2772 	}
2773 	dbg(" Discarding orphan fragment %x\n",fbuf);
2774 	msg_dbg(fragm,"ORPHAN:");
2775 	dbg("Pending long buffers:\n");
2776 	dbg_print_buf_chain(*pending);
2777 	buf_discard(fbuf);
2778 	return 0;
2779 }
2780 
2781 /**
2782  * link_check_defragm_bufs - flush stale incoming message fragments
2783  * @l_ptr: pointer to link
2784  */
2785 
2786 static void link_check_defragm_bufs(struct link *l_ptr)
2787 {
2788 	struct sk_buff *prev = NULL;
2789 	struct sk_buff *next = NULL;
2790 	struct sk_buff *buf = l_ptr->defragm_buf;
2791 
2792 	if (!buf)
2793 		return;
2794 	if (!link_working_working(l_ptr))
2795 		return;
2796 	while (buf) {
2797 		u32 cnt = get_timer_cnt(buf);
2798 
2799 		next = buf->next;
2800 		if (cnt < 4) {
2801 			incr_timer_cnt(buf);
2802 			prev = buf;
2803 		} else {
2804 			dbg(" Discarding incomplete long buffer\n");
2805 			msg_dbg(buf_msg(buf), "LONG:");
2806 			dbg_print_link(l_ptr, "curr:");
2807 			dbg("Pending long buffers:\n");
2808 			dbg_print_buf_chain(l_ptr->defragm_buf);
2809 			if (prev)
2810 				prev->next = buf->next;
2811 			else
2812 				l_ptr->defragm_buf = buf->next;
2813 			buf_discard(buf);
2814 		}
2815 		buf = next;
2816 	}
2817 }
2818 
2819 
2820 
2821 static void link_set_supervision_props(struct link *l_ptr, u32 tolerance)
2822 {
2823 	l_ptr->tolerance = tolerance;
2824 	l_ptr->continuity_interval =
2825 		((tolerance / 4) > 500) ? 500 : tolerance / 4;
2826 	l_ptr->abort_limit = tolerance / (l_ptr->continuity_interval / 4);
2827 }
2828 
2829 
2830 void tipc_link_set_queue_limits(struct link *l_ptr, u32 window)
2831 {
2832 	/* Data messages from this node, inclusive FIRST_FRAGM */
2833 	l_ptr->queue_limit[DATA_LOW] = window;
2834 	l_ptr->queue_limit[DATA_MEDIUM] = (window / 3) * 4;
2835 	l_ptr->queue_limit[DATA_HIGH] = (window / 3) * 5;
2836 	l_ptr->queue_limit[DATA_CRITICAL] = (window / 3) * 6;
2837 	/* Transiting data messages,inclusive FIRST_FRAGM */
2838 	l_ptr->queue_limit[DATA_LOW + 4] = 300;
2839 	l_ptr->queue_limit[DATA_MEDIUM + 4] = 600;
2840 	l_ptr->queue_limit[DATA_HIGH + 4] = 900;
2841 	l_ptr->queue_limit[DATA_CRITICAL + 4] = 1200;
2842 	l_ptr->queue_limit[CONN_MANAGER] = 1200;
2843 	l_ptr->queue_limit[ROUTE_DISTRIBUTOR] = 1200;
2844 	l_ptr->queue_limit[CHANGEOVER_PROTOCOL] = 2500;
2845 	l_ptr->queue_limit[NAME_DISTRIBUTOR] = 3000;
2846 	/* FRAGMENT and LAST_FRAGMENT packets */
2847 	l_ptr->queue_limit[MSG_FRAGMENTER] = 4000;
2848 }
2849 
2850 /**
2851  * link_find_link - locate link by name
2852  * @name - ptr to link name string
2853  * @node - ptr to area to be filled with ptr to associated node
2854  *
2855  * Caller must hold 'tipc_net_lock' to ensure node and bearer are not deleted;
2856  * this also prevents link deletion.
2857  *
2858  * Returns pointer to link (or 0 if invalid link name).
2859  */
2860 
2861 static struct link *link_find_link(const char *name, struct node **node)
2862 {
2863 	struct link_name link_name_parts;
2864 	struct bearer *b_ptr;
2865 	struct link *l_ptr;
2866 
2867 	if (!link_name_validate(name, &link_name_parts))
2868 		return NULL;
2869 
2870 	b_ptr = tipc_bearer_find_interface(link_name_parts.if_local);
2871 	if (!b_ptr)
2872 		return NULL;
2873 
2874 	*node = tipc_node_find(link_name_parts.addr_peer);
2875 	if (!*node)
2876 		return NULL;
2877 
2878 	l_ptr = (*node)->links[b_ptr->identity];
2879 	if (!l_ptr || strcmp(l_ptr->name, name))
2880 		return NULL;
2881 
2882 	return l_ptr;
2883 }
2884 
2885 struct sk_buff *tipc_link_cmd_config(const void *req_tlv_area, int req_tlv_space,
2886 				     u16 cmd)
2887 {
2888 	struct tipc_link_config *args;
2889 	u32 new_value;
2890 	struct link *l_ptr;
2891 	struct node *node;
2892 	int res;
2893 
2894 	if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_CONFIG))
2895 		return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2896 
2897 	args = (struct tipc_link_config *)TLV_DATA(req_tlv_area);
2898 	new_value = ntohl(args->value);
2899 
2900 	if (!strcmp(args->name, tipc_bclink_name)) {
2901 		if ((cmd == TIPC_CMD_SET_LINK_WINDOW) &&
2902 		    (tipc_bclink_set_queue_limits(new_value) == 0))
2903 			return tipc_cfg_reply_none();
2904 		return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
2905 						   " (cannot change setting on broadcast link)");
2906 	}
2907 
2908 	read_lock_bh(&tipc_net_lock);
2909 	l_ptr = link_find_link(args->name, &node);
2910 	if (!l_ptr) {
2911 		read_unlock_bh(&tipc_net_lock);
2912 		return tipc_cfg_reply_error_string("link not found");
2913 	}
2914 
2915 	tipc_node_lock(node);
2916 	res = -EINVAL;
2917 	switch (cmd) {
2918 	case TIPC_CMD_SET_LINK_TOL:
2919 		if ((new_value >= TIPC_MIN_LINK_TOL) &&
2920 		    (new_value <= TIPC_MAX_LINK_TOL)) {
2921 			link_set_supervision_props(l_ptr, new_value);
2922 			tipc_link_send_proto_msg(l_ptr, STATE_MSG,
2923 						 0, 0, new_value, 0, 0);
2924 			res = TIPC_OK;
2925 		}
2926 		break;
2927 	case TIPC_CMD_SET_LINK_PRI:
2928 		if ((new_value >= TIPC_MIN_LINK_PRI) &&
2929 		    (new_value <= TIPC_MAX_LINK_PRI)) {
2930 			l_ptr->priority = new_value;
2931 			tipc_link_send_proto_msg(l_ptr, STATE_MSG,
2932 						 0, 0, 0, new_value, 0);
2933 			res = TIPC_OK;
2934 		}
2935 		break;
2936 	case TIPC_CMD_SET_LINK_WINDOW:
2937 		if ((new_value >= TIPC_MIN_LINK_WIN) &&
2938 		    (new_value <= TIPC_MAX_LINK_WIN)) {
2939 			tipc_link_set_queue_limits(l_ptr, new_value);
2940 			res = TIPC_OK;
2941 		}
2942 		break;
2943 	}
2944 	tipc_node_unlock(node);
2945 
2946 	read_unlock_bh(&tipc_net_lock);
2947 	if (res)
2948 		return tipc_cfg_reply_error_string("cannot change link setting");
2949 
2950 	return tipc_cfg_reply_none();
2951 }
2952 
2953 /**
2954  * link_reset_statistics - reset link statistics
2955  * @l_ptr: pointer to link
2956  */
2957 
2958 static void link_reset_statistics(struct link *l_ptr)
2959 {
2960 	memset(&l_ptr->stats, 0, sizeof(l_ptr->stats));
2961 	l_ptr->stats.sent_info = l_ptr->next_out_no;
2962 	l_ptr->stats.recv_info = l_ptr->next_in_no;
2963 }
2964 
2965 struct sk_buff *tipc_link_cmd_reset_stats(const void *req_tlv_area, int req_tlv_space)
2966 {
2967 	char *link_name;
2968 	struct link *l_ptr;
2969 	struct node *node;
2970 
2971 	if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_NAME))
2972 		return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2973 
2974 	link_name = (char *)TLV_DATA(req_tlv_area);
2975 	if (!strcmp(link_name, tipc_bclink_name)) {
2976 		if (tipc_bclink_reset_stats())
2977 			return tipc_cfg_reply_error_string("link not found");
2978 		return tipc_cfg_reply_none();
2979 	}
2980 
2981 	read_lock_bh(&tipc_net_lock);
2982 	l_ptr = link_find_link(link_name, &node);
2983 	if (!l_ptr) {
2984 		read_unlock_bh(&tipc_net_lock);
2985 		return tipc_cfg_reply_error_string("link not found");
2986 	}
2987 
2988 	tipc_node_lock(node);
2989 	link_reset_statistics(l_ptr);
2990 	tipc_node_unlock(node);
2991 	read_unlock_bh(&tipc_net_lock);
2992 	return tipc_cfg_reply_none();
2993 }
2994 
2995 /**
2996  * percent - convert count to a percentage of total (rounding up or down)
2997  */
2998 
2999 static u32 percent(u32 count, u32 total)
3000 {
3001 	return (count * 100 + (total / 2)) / total;
3002 }
3003 
3004 /**
3005  * tipc_link_stats - print link statistics
3006  * @name: link name
3007  * @buf: print buffer area
3008  * @buf_size: size of print buffer area
3009  *
3010  * Returns length of print buffer data string (or 0 if error)
3011  */
3012 
3013 static int tipc_link_stats(const char *name, char *buf, const u32 buf_size)
3014 {
3015 	struct print_buf pb;
3016 	struct link *l_ptr;
3017 	struct node *node;
3018 	char *status;
3019 	u32 profile_total = 0;
3020 
3021 	if (!strcmp(name, tipc_bclink_name))
3022 		return tipc_bclink_stats(buf, buf_size);
3023 
3024 	tipc_printbuf_init(&pb, buf, buf_size);
3025 
3026 	read_lock_bh(&tipc_net_lock);
3027 	l_ptr = link_find_link(name, &node);
3028 	if (!l_ptr) {
3029 		read_unlock_bh(&tipc_net_lock);
3030 		return 0;
3031 	}
3032 	tipc_node_lock(node);
3033 
3034 	if (tipc_link_is_active(l_ptr))
3035 		status = "ACTIVE";
3036 	else if (tipc_link_is_up(l_ptr))
3037 		status = "STANDBY";
3038 	else
3039 		status = "DEFUNCT";
3040 	tipc_printf(&pb, "Link <%s>\n"
3041 			 "  %s  MTU:%u  Priority:%u  Tolerance:%u ms"
3042 			 "  Window:%u packets\n",
3043 		    l_ptr->name, status, link_max_pkt(l_ptr),
3044 		    l_ptr->priority, l_ptr->tolerance, l_ptr->queue_limit[0]);
3045 	tipc_printf(&pb, "  RX packets:%u fragments:%u/%u bundles:%u/%u\n",
3046 		    l_ptr->next_in_no - l_ptr->stats.recv_info,
3047 		    l_ptr->stats.recv_fragments,
3048 		    l_ptr->stats.recv_fragmented,
3049 		    l_ptr->stats.recv_bundles,
3050 		    l_ptr->stats.recv_bundled);
3051 	tipc_printf(&pb, "  TX packets:%u fragments:%u/%u bundles:%u/%u\n",
3052 		    l_ptr->next_out_no - l_ptr->stats.sent_info,
3053 		    l_ptr->stats.sent_fragments,
3054 		    l_ptr->stats.sent_fragmented,
3055 		    l_ptr->stats.sent_bundles,
3056 		    l_ptr->stats.sent_bundled);
3057 	profile_total = l_ptr->stats.msg_length_counts;
3058 	if (!profile_total)
3059 		profile_total = 1;
3060 	tipc_printf(&pb, "  TX profile sample:%u packets  average:%u octets\n"
3061 			 "  0-64:%u%% -256:%u%% -1024:%u%% -4096:%u%% "
3062 			 "-16354:%u%% -32768:%u%% -66000:%u%%\n",
3063 		    l_ptr->stats.msg_length_counts,
3064 		    l_ptr->stats.msg_lengths_total / profile_total,
3065 		    percent(l_ptr->stats.msg_length_profile[0], profile_total),
3066 		    percent(l_ptr->stats.msg_length_profile[1], profile_total),
3067 		    percent(l_ptr->stats.msg_length_profile[2], profile_total),
3068 		    percent(l_ptr->stats.msg_length_profile[3], profile_total),
3069 		    percent(l_ptr->stats.msg_length_profile[4], profile_total),
3070 		    percent(l_ptr->stats.msg_length_profile[5], profile_total),
3071 		    percent(l_ptr->stats.msg_length_profile[6], profile_total));
3072 	tipc_printf(&pb, "  RX states:%u probes:%u naks:%u defs:%u dups:%u\n",
3073 		    l_ptr->stats.recv_states,
3074 		    l_ptr->stats.recv_probes,
3075 		    l_ptr->stats.recv_nacks,
3076 		    l_ptr->stats.deferred_recv,
3077 		    l_ptr->stats.duplicates);
3078 	tipc_printf(&pb, "  TX states:%u probes:%u naks:%u acks:%u dups:%u\n",
3079 		    l_ptr->stats.sent_states,
3080 		    l_ptr->stats.sent_probes,
3081 		    l_ptr->stats.sent_nacks,
3082 		    l_ptr->stats.sent_acks,
3083 		    l_ptr->stats.retransmitted);
3084 	tipc_printf(&pb, "  Congestion bearer:%u link:%u  Send queue max:%u avg:%u\n",
3085 		    l_ptr->stats.bearer_congs,
3086 		    l_ptr->stats.link_congs,
3087 		    l_ptr->stats.max_queue_sz,
3088 		    l_ptr->stats.queue_sz_counts
3089 		    ? (l_ptr->stats.accu_queue_sz / l_ptr->stats.queue_sz_counts)
3090 		    : 0);
3091 
3092 	tipc_node_unlock(node);
3093 	read_unlock_bh(&tipc_net_lock);
3094 	return tipc_printbuf_validate(&pb);
3095 }
3096 
3097 #define MAX_LINK_STATS_INFO 2000
3098 
3099 struct sk_buff *tipc_link_cmd_show_stats(const void *req_tlv_area, int req_tlv_space)
3100 {
3101 	struct sk_buff *buf;
3102 	struct tlv_desc *rep_tlv;
3103 	int str_len;
3104 
3105 	if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_NAME))
3106 		return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
3107 
3108 	buf = tipc_cfg_reply_alloc(TLV_SPACE(MAX_LINK_STATS_INFO));
3109 	if (!buf)
3110 		return NULL;
3111 
3112 	rep_tlv = (struct tlv_desc *)buf->data;
3113 
3114 	str_len = tipc_link_stats((char *)TLV_DATA(req_tlv_area),
3115 				  (char *)TLV_DATA(rep_tlv), MAX_LINK_STATS_INFO);
3116 	if (!str_len) {
3117 		buf_discard(buf);
3118 		return tipc_cfg_reply_error_string("link not found");
3119 	}
3120 
3121 	skb_put(buf, TLV_SPACE(str_len));
3122 	TLV_SET(rep_tlv, TIPC_TLV_ULTRA_STRING, NULL, str_len);
3123 
3124 	return buf;
3125 }
3126 
3127 #if 0
3128 int link_control(const char *name, u32 op, u32 val)
3129 {
3130 	int res = -EINVAL;
3131 	struct link *l_ptr;
3132 	u32 bearer_id;
3133 	struct node * node;
3134 	u32 a;
3135 
3136 	a = link_name2addr(name, &bearer_id);
3137 	read_lock_bh(&tipc_net_lock);
3138 	node = tipc_node_find(a);
3139 	if (node) {
3140 		tipc_node_lock(node);
3141 		l_ptr = node->links[bearer_id];
3142 		if (l_ptr) {
3143 			if (op == TIPC_REMOVE_LINK) {
3144 				struct bearer *b_ptr = l_ptr->b_ptr;
3145 				spin_lock_bh(&b_ptr->publ.lock);
3146 				tipc_link_delete(l_ptr);
3147 				spin_unlock_bh(&b_ptr->publ.lock);
3148 			}
3149 			if (op == TIPC_CMD_BLOCK_LINK) {
3150 				tipc_link_reset(l_ptr);
3151 				l_ptr->blocked = 1;
3152 			}
3153 			if (op == TIPC_CMD_UNBLOCK_LINK) {
3154 				l_ptr->blocked = 0;
3155 			}
3156 			res = TIPC_OK;
3157 		}
3158 		tipc_node_unlock(node);
3159 	}
3160 	read_unlock_bh(&tipc_net_lock);
3161 	return res;
3162 }
3163 #endif
3164 
3165 /**
3166  * tipc_link_get_max_pkt - get maximum packet size to use when sending to destination
3167  * @dest: network address of destination node
3168  * @selector: used to select from set of active links
3169  *
3170  * If no active link can be found, uses default maximum packet size.
3171  */
3172 
3173 u32 tipc_link_get_max_pkt(u32 dest, u32 selector)
3174 {
3175 	struct node *n_ptr;
3176 	struct link *l_ptr;
3177 	u32 res = MAX_PKT_DEFAULT;
3178 
3179 	if (dest == tipc_own_addr)
3180 		return MAX_MSG_SIZE;
3181 
3182 	read_lock_bh(&tipc_net_lock);
3183 	n_ptr = tipc_node_select(dest, selector);
3184 	if (n_ptr) {
3185 		tipc_node_lock(n_ptr);
3186 		l_ptr = n_ptr->active_links[selector & 1];
3187 		if (l_ptr)
3188 			res = link_max_pkt(l_ptr);
3189 		tipc_node_unlock(n_ptr);
3190 	}
3191 	read_unlock_bh(&tipc_net_lock);
3192 	return res;
3193 }
3194 
3195 #if 0
3196 static void link_dump_rec_queue(struct link *l_ptr)
3197 {
3198 	struct sk_buff *crs;
3199 
3200 	if (!l_ptr->oldest_deferred_in) {
3201 		info("Reception queue empty\n");
3202 		return;
3203 	}
3204 	info("Contents of Reception queue:\n");
3205 	crs = l_ptr->oldest_deferred_in;
3206 	while (crs) {
3207 		if (crs->data == (void *)0x0000a3a3) {
3208 			info("buffer %x invalid\n", crs);
3209 			return;
3210 		}
3211 		msg_dbg(buf_msg(crs), "In rec queue: \n");
3212 		crs = crs->next;
3213 	}
3214 }
3215 #endif
3216 
3217 static void link_dump_send_queue(struct link *l_ptr)
3218 {
3219 	if (l_ptr->next_out) {
3220 		info("\nContents of unsent queue:\n");
3221 		dbg_print_buf_chain(l_ptr->next_out);
3222 	}
3223 	info("\nContents of send queue:\n");
3224 	if (l_ptr->first_out) {
3225 		dbg_print_buf_chain(l_ptr->first_out);
3226 	}
3227 	info("Empty send queue\n");
3228 }
3229 
3230 static void link_print(struct link *l_ptr, struct print_buf *buf,
3231 		       const char *str)
3232 {
3233 	tipc_printf(buf, str);
3234 	if (link_reset_reset(l_ptr) || link_reset_unknown(l_ptr))
3235 		return;
3236 	tipc_printf(buf, "Link %x<%s>:",
3237 		    l_ptr->addr, l_ptr->b_ptr->publ.name);
3238 	tipc_printf(buf, ": NXO(%u):", mod(l_ptr->next_out_no));
3239 	tipc_printf(buf, "NXI(%u):", mod(l_ptr->next_in_no));
3240 	tipc_printf(buf, "SQUE");
3241 	if (l_ptr->first_out) {
3242 		tipc_printf(buf, "[%u..", msg_seqno(buf_msg(l_ptr->first_out)));
3243 		if (l_ptr->next_out)
3244 			tipc_printf(buf, "%u..",
3245 				    msg_seqno(buf_msg(l_ptr->next_out)));
3246 		tipc_printf(buf, "%u]",
3247 			    msg_seqno(buf_msg
3248 				      (l_ptr->last_out)), l_ptr->out_queue_size);
3249 		if ((mod(msg_seqno(buf_msg(l_ptr->last_out)) -
3250 			 msg_seqno(buf_msg(l_ptr->first_out)))
3251 		     != (l_ptr->out_queue_size - 1))
3252 		    || (l_ptr->last_out->next != 0)) {
3253 			tipc_printf(buf, "\nSend queue inconsistency\n");
3254 			tipc_printf(buf, "first_out= %x ", l_ptr->first_out);
3255 			tipc_printf(buf, "next_out= %x ", l_ptr->next_out);
3256 			tipc_printf(buf, "last_out= %x ", l_ptr->last_out);
3257 			link_dump_send_queue(l_ptr);
3258 		}
3259 	} else
3260 		tipc_printf(buf, "[]");
3261 	tipc_printf(buf, "SQSIZ(%u)", l_ptr->out_queue_size);
3262 	if (l_ptr->oldest_deferred_in) {
3263 		u32 o = msg_seqno(buf_msg(l_ptr->oldest_deferred_in));
3264 		u32 n = msg_seqno(buf_msg(l_ptr->newest_deferred_in));
3265 		tipc_printf(buf, ":RQUE[%u..%u]", o, n);
3266 		if (l_ptr->deferred_inqueue_sz != mod((n + 1) - o)) {
3267 			tipc_printf(buf, ":RQSIZ(%u)",
3268 				    l_ptr->deferred_inqueue_sz);
3269 		}
3270 	}
3271 	if (link_working_unknown(l_ptr))
3272 		tipc_printf(buf, ":WU");
3273 	if (link_reset_reset(l_ptr))
3274 		tipc_printf(buf, ":RR");
3275 	if (link_reset_unknown(l_ptr))
3276 		tipc_printf(buf, ":RU");
3277 	if (link_working_working(l_ptr))
3278 		tipc_printf(buf, ":WW");
3279 	tipc_printf(buf, "\n");
3280 }
3281 
3282