xref: /linux/net/tipc/link.c (revision d8327c784b51b57dac2c26cfad87dce0d68dfd98)
1 /*
2  * net/tipc/link.c: TIPC link code
3  *
4  * Copyright (c) 1996-2006, Ericsson AB
5  * Copyright (c) 2004-2005, Wind River Systems
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions are met:
10  *
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. Neither the names of the copyright holders nor the names of its
17  *    contributors may be used to endorse or promote products derived from
18  *    this software without specific prior written permission.
19  *
20  * Alternatively, this software may be distributed under the terms of the
21  * GNU General Public License ("GPL") version 2 as published by the Free
22  * Software Foundation.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
25  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
28  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
29  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
30  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
31  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
32  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
33  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
34  * POSSIBILITY OF SUCH DAMAGE.
35  */
36 
37 #include "core.h"
38 #include "dbg.h"
39 #include "link.h"
40 #include "net.h"
41 #include "node.h"
42 #include "port.h"
43 #include "addr.h"
44 #include "node_subscr.h"
45 #include "name_distr.h"
46 #include "bearer.h"
47 #include "name_table.h"
48 #include "discover.h"
49 #include "config.h"
50 #include "bcast.h"
51 
52 
53 /*
54  * Limit for deferred reception queue:
55  */
56 
57 #define DEF_QUEUE_LIMIT 256u
58 
59 /*
60  * Link state events:
61  */
62 
63 #define  STARTING_EVT    856384768	/* link processing trigger */
64 #define  TRAFFIC_MSG_EVT 560815u	/* rx'd ??? */
65 #define  TIMEOUT_EVT     560817u	/* link timer expired */
66 
67 /*
68  * The following two 'message types' is really just implementation
69  * data conveniently stored in the message header.
70  * They must not be considered part of the protocol
71  */
72 #define OPEN_MSG   0
73 #define CLOSED_MSG 1
74 
75 /*
76  * State value stored in 'exp_msg_count'
77  */
78 
79 #define START_CHANGEOVER 100000u
80 
81 /**
82  * struct link_name - deconstructed link name
83  * @addr_local: network address of node at this end
84  * @if_local: name of interface at this end
85  * @addr_peer: network address of node at far end
86  * @if_peer: name of interface at far end
87  */
88 
89 struct link_name {
90 	u32 addr_local;
91 	char if_local[TIPC_MAX_IF_NAME];
92 	u32 addr_peer;
93 	char if_peer[TIPC_MAX_IF_NAME];
94 };
95 
96 #if 0
97 
98 /* LINK EVENT CODE IS NOT SUPPORTED AT PRESENT */
99 
100 /**
101  * struct link_event - link up/down event notification
102  */
103 
104 struct link_event {
105 	u32 addr;
106 	int up;
107 	void (*fcn)(u32, char *, int);
108 	char name[TIPC_MAX_LINK_NAME];
109 };
110 
111 #endif
112 
113 static void link_handle_out_of_seq_msg(struct link *l_ptr,
114 				       struct sk_buff *buf);
115 static void link_recv_proto_msg(struct link *l_ptr, struct sk_buff *buf);
116 static int  link_recv_changeover_msg(struct link **l_ptr, struct sk_buff **buf);
117 static void link_set_supervision_props(struct link *l_ptr, u32 tolerance);
118 static int  link_send_sections_long(struct port *sender,
119 				    struct iovec const *msg_sect,
120 				    u32 num_sect, u32 destnode);
121 static void link_check_defragm_bufs(struct link *l_ptr);
122 static void link_state_event(struct link *l_ptr, u32 event);
123 static void link_reset_statistics(struct link *l_ptr);
124 static void link_print(struct link *l_ptr, struct print_buf *buf,
125 		       const char *str);
126 
127 /*
128  * Debugging code used by link routines only
129  *
130  * When debugging link problems on a system that has multiple links,
131  * the standard TIPC debugging routines may not be useful since they
132  * allow the output from multiple links to be intermixed.  For this reason
133  * routines of the form "dbg_link_XXX()" have been created that will capture
134  * debug info into a link's personal print buffer, which can then be dumped
135  * into the TIPC system log (LOG) upon request.
136  *
137  * To enable per-link debugging, use LINK_LOG_BUF_SIZE to specify the size
138  * of the print buffer used by each link.  If LINK_LOG_BUF_SIZE is set to 0,
139  * the dbg_link_XXX() routines simply send their output to the standard
140  * debug print buffer (DBG_OUTPUT), if it has been defined; this can be useful
141  * when there is only a single link in the system being debugged.
142  *
143  * Notes:
144  * - When enabled, LINK_LOG_BUF_SIZE should be set to at least 1000 (bytes)
145  * - "l_ptr" must be valid when using dbg_link_XXX() macros
146  */
147 
148 #define LINK_LOG_BUF_SIZE 0
149 
150 #define dbg_link(fmt, arg...)  do {if (LINK_LOG_BUF_SIZE) tipc_printf(&l_ptr->print_buf, fmt, ## arg); } while(0)
151 #define dbg_link_msg(msg, txt) do {if (LINK_LOG_BUF_SIZE) tipc_msg_print(&l_ptr->print_buf, msg, txt); } while(0)
152 #define dbg_link_state(txt) do {if (LINK_LOG_BUF_SIZE) link_print(l_ptr, &l_ptr->print_buf, txt); } while(0)
153 #define dbg_link_dump() do { \
154 	if (LINK_LOG_BUF_SIZE) { \
155 		tipc_printf(LOG, "\n\nDumping link <%s>:\n", l_ptr->name); \
156 		tipc_printbuf_move(LOG, &l_ptr->print_buf); \
157 	} \
158 } while (0)
159 
160 static inline void dbg_print_link(struct link *l_ptr, const char *str)
161 {
162 	if (DBG_OUTPUT)
163 		link_print(l_ptr, DBG_OUTPUT, str);
164 }
165 
166 static inline void dbg_print_buf_chain(struct sk_buff *root_buf)
167 {
168 	if (DBG_OUTPUT) {
169 		struct sk_buff *buf = root_buf;
170 
171 		while (buf) {
172 			msg_dbg(buf_msg(buf), "In chain: ");
173 			buf = buf->next;
174 		}
175 	}
176 }
177 
178 /*
179  *  Simple inlined link routines
180  */
181 
182 static inline unsigned int align(unsigned int i)
183 {
184 	return (i + 3) & ~3u;
185 }
186 
187 static inline int link_working_working(struct link *l_ptr)
188 {
189 	return (l_ptr->state == WORKING_WORKING);
190 }
191 
192 static inline int link_working_unknown(struct link *l_ptr)
193 {
194 	return (l_ptr->state == WORKING_UNKNOWN);
195 }
196 
197 static inline int link_reset_unknown(struct link *l_ptr)
198 {
199 	return (l_ptr->state == RESET_UNKNOWN);
200 }
201 
202 static inline int link_reset_reset(struct link *l_ptr)
203 {
204 	return (l_ptr->state == RESET_RESET);
205 }
206 
207 static inline int link_blocked(struct link *l_ptr)
208 {
209 	return (l_ptr->exp_msg_count || l_ptr->blocked);
210 }
211 
212 static inline int link_congested(struct link *l_ptr)
213 {
214 	return (l_ptr->out_queue_size >= l_ptr->queue_limit[0]);
215 }
216 
217 static inline u32 link_max_pkt(struct link *l_ptr)
218 {
219 	return l_ptr->max_pkt;
220 }
221 
222 static inline 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 inline 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 inline u32 link_last_sent(struct link *l_ptr)
247 {
248 	return mod(link_next_sent(l_ptr) - 1);
249 }
250 
251 /*
252  *  Simple non-inlined 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 inline void link_set_timer(struct link *l_ptr, u32 time)
400 {
401 	k_start_timer(&l_ptr->timer, time);
402 }
403 
404 /**
405  * tipc_link_create - create a new link
406  * @b_ptr: pointer to associated bearer
407  * @peer: network address of node at other end of link
408  * @media_addr: media address to use when sending messages over link
409  *
410  * Returns pointer to link.
411  */
412 
413 struct link *tipc_link_create(struct bearer *b_ptr, const u32 peer,
414 			      const struct tipc_media_addr *media_addr)
415 {
416 	struct link *l_ptr;
417 	struct tipc_msg *msg;
418 	char *if_name;
419 
420 	l_ptr = (struct link *)kmalloc(sizeof(*l_ptr), GFP_ATOMIC);
421 	if (!l_ptr) {
422 		warn("Memory squeeze; Failed to create link\n");
423 		return NULL;
424 	}
425 	memset(l_ptr, 0, sizeof(*l_ptr));
426 
427 	l_ptr->addr = peer;
428 	if_name = strchr(b_ptr->publ.name, ':') + 1;
429 	sprintf(l_ptr->name, "%u.%u.%u:%s-%u.%u.%u:",
430 		tipc_zone(tipc_own_addr), tipc_cluster(tipc_own_addr),
431 		tipc_node(tipc_own_addr),
432 		if_name,
433 		tipc_zone(peer), tipc_cluster(peer), tipc_node(peer));
434 		/* note: peer i/f is appended to link name by reset/activate */
435 	memcpy(&l_ptr->media_addr, media_addr, sizeof(*media_addr));
436 	k_init_timer(&l_ptr->timer, (Handler)link_timeout, (unsigned long)l_ptr);
437 	list_add_tail(&l_ptr->link_list, &b_ptr->links);
438 	l_ptr->checkpoint = 1;
439 	l_ptr->b_ptr = b_ptr;
440 	link_set_supervision_props(l_ptr, b_ptr->media->tolerance);
441 	l_ptr->state = RESET_UNKNOWN;
442 
443 	l_ptr->pmsg = (struct tipc_msg *)&l_ptr->proto_msg;
444 	msg = l_ptr->pmsg;
445 	msg_init(msg, LINK_PROTOCOL, RESET_MSG, TIPC_OK, INT_H_SIZE, l_ptr->addr);
446 	msg_set_size(msg, sizeof(l_ptr->proto_msg));
447 	msg_set_session(msg, tipc_random);
448 	msg_set_bearer_id(msg, b_ptr->identity);
449 	strcpy((char *)msg_data(msg), if_name);
450 
451 	l_ptr->priority = b_ptr->priority;
452 	tipc_link_set_queue_limits(l_ptr, b_ptr->media->window);
453 
454 	link_init_max_pkt(l_ptr);
455 
456 	l_ptr->next_out_no = 1;
457 	INIT_LIST_HEAD(&l_ptr->waiting_ports);
458 
459 	link_reset_statistics(l_ptr);
460 
461 	l_ptr->owner = tipc_node_attach_link(l_ptr);
462 	if (!l_ptr->owner) {
463 		kfree(l_ptr);
464 		return NULL;
465 	}
466 
467 	if (LINK_LOG_BUF_SIZE) {
468 		char *pb = kmalloc(LINK_LOG_BUF_SIZE, GFP_ATOMIC);
469 
470 		if (!pb) {
471 			kfree(l_ptr);
472 			warn("Memory squeeze; Failed to create link\n");
473 			return NULL;
474 		}
475 		tipc_printbuf_init(&l_ptr->print_buf, pb, LINK_LOG_BUF_SIZE);
476 	}
477 
478 	tipc_k_signal((Handler)tipc_link_start, (unsigned long)l_ptr);
479 
480 	dbg("tipc_link_create(): tolerance = %u,cont intv = %u, abort_limit = %u\n",
481 	    l_ptr->tolerance, l_ptr->continuity_interval, l_ptr->abort_limit);
482 
483 	return l_ptr;
484 }
485 
486 /**
487  * tipc_link_delete - delete a link
488  * @l_ptr: pointer to link
489  *
490  * Note: 'tipc_net_lock' is write_locked, bearer is locked.
491  * This routine must not grab the node lock until after link timer cancellation
492  * to avoid a potential deadlock situation.
493  */
494 
495 void tipc_link_delete(struct link *l_ptr)
496 {
497 	if (!l_ptr) {
498 		err("Attempt to delete non-existent link\n");
499 		return;
500 	}
501 
502 	dbg("tipc_link_delete()\n");
503 
504 	k_cancel_timer(&l_ptr->timer);
505 
506 	tipc_node_lock(l_ptr->owner);
507 	tipc_link_reset(l_ptr);
508 	tipc_node_detach_link(l_ptr->owner, l_ptr);
509 	tipc_link_stop(l_ptr);
510 	list_del_init(&l_ptr->link_list);
511 	if (LINK_LOG_BUF_SIZE)
512 		kfree(l_ptr->print_buf.buf);
513 	tipc_node_unlock(l_ptr->owner);
514 	k_term_timer(&l_ptr->timer);
515 	kfree(l_ptr);
516 }
517 
518 void tipc_link_start(struct link *l_ptr)
519 {
520 	dbg("tipc_link_start %x\n", l_ptr);
521 	link_state_event(l_ptr, STARTING_EVT);
522 }
523 
524 /**
525  * link_schedule_port - schedule port for deferred sending
526  * @l_ptr: pointer to link
527  * @origport: reference to sending port
528  * @sz: amount of data to be sent
529  *
530  * Schedules port for renewed sending of messages after link congestion
531  * has abated.
532  */
533 
534 static int link_schedule_port(struct link *l_ptr, u32 origport, u32 sz)
535 {
536 	struct port *p_ptr;
537 
538 	spin_lock_bh(&tipc_port_list_lock);
539 	p_ptr = tipc_port_lock(origport);
540 	if (p_ptr) {
541 		if (!p_ptr->wakeup)
542 			goto exit;
543 		if (!list_empty(&p_ptr->wait_list))
544 			goto exit;
545 		p_ptr->congested_link = l_ptr;
546 		p_ptr->publ.congested = 1;
547 		p_ptr->waiting_pkts = 1 + ((sz - 1) / link_max_pkt(l_ptr));
548 		list_add_tail(&p_ptr->wait_list, &l_ptr->waiting_ports);
549 		l_ptr->stats.link_congs++;
550 exit:
551 		tipc_port_unlock(p_ptr);
552 	}
553 	spin_unlock_bh(&tipc_port_list_lock);
554 	return -ELINKCONG;
555 }
556 
557 void tipc_link_wakeup_ports(struct link *l_ptr, int all)
558 {
559 	struct port *p_ptr;
560 	struct port *temp_p_ptr;
561 	int win = l_ptr->queue_limit[0] - l_ptr->out_queue_size;
562 
563 	if (all)
564 		win = 100000;
565 	if (win <= 0)
566 		return;
567 	if (!spin_trylock_bh(&tipc_port_list_lock))
568 		return;
569 	if (link_congested(l_ptr))
570 		goto exit;
571 	list_for_each_entry_safe(p_ptr, temp_p_ptr, &l_ptr->waiting_ports,
572 				 wait_list) {
573 		if (win <= 0)
574 			break;
575 		list_del_init(&p_ptr->wait_list);
576 		p_ptr->congested_link = 0;
577 		assert(p_ptr->wakeup);
578 		spin_lock_bh(p_ptr->publ.lock);
579 		p_ptr->publ.congested = 0;
580 		p_ptr->wakeup(&p_ptr->publ);
581 		win -= p_ptr->waiting_pkts;
582 		spin_unlock_bh(p_ptr->publ.lock);
583 	}
584 
585 exit:
586 	spin_unlock_bh(&tipc_port_list_lock);
587 }
588 
589 /**
590  * link_release_outqueue - purge link's outbound message queue
591  * @l_ptr: pointer to link
592  */
593 
594 static void link_release_outqueue(struct link *l_ptr)
595 {
596 	struct sk_buff *buf = l_ptr->first_out;
597 	struct sk_buff *next;
598 
599 	while (buf) {
600 		next = buf->next;
601 		buf_discard(buf);
602 		buf = next;
603 	}
604 	l_ptr->first_out = NULL;
605 	l_ptr->out_queue_size = 0;
606 }
607 
608 /**
609  * tipc_link_reset_fragments - purge link's inbound message fragments queue
610  * @l_ptr: pointer to link
611  */
612 
613 void tipc_link_reset_fragments(struct link *l_ptr)
614 {
615 	struct sk_buff *buf = l_ptr->defragm_buf;
616 	struct sk_buff *next;
617 
618 	while (buf) {
619 		next = buf->next;
620 		buf_discard(buf);
621 		buf = next;
622 	}
623 	l_ptr->defragm_buf = NULL;
624 }
625 
626 /**
627  * tipc_link_stop - purge all inbound and outbound messages associated with link
628  * @l_ptr: pointer to link
629  */
630 
631 void tipc_link_stop(struct link *l_ptr)
632 {
633 	struct sk_buff *buf;
634 	struct sk_buff *next;
635 
636 	buf = l_ptr->oldest_deferred_in;
637 	while (buf) {
638 		next = buf->next;
639 		buf_discard(buf);
640 		buf = next;
641 	}
642 
643 	buf = l_ptr->first_out;
644 	while (buf) {
645 		next = buf->next;
646 		buf_discard(buf);
647 		buf = next;
648 	}
649 
650 	tipc_link_reset_fragments(l_ptr);
651 
652 	buf_discard(l_ptr->proto_msg_queue);
653 	l_ptr->proto_msg_queue = NULL;
654 }
655 
656 #if 0
657 
658 /* LINK EVENT CODE IS NOT SUPPORTED AT PRESENT */
659 
660 static void link_recv_event(struct link_event *ev)
661 {
662 	ev->fcn(ev->addr, ev->name, ev->up);
663 	kfree(ev);
664 }
665 
666 static void link_send_event(void (*fcn)(u32 a, char *n, int up),
667 			    struct link *l_ptr, int up)
668 {
669 	struct link_event *ev;
670 
671 	ev = kmalloc(sizeof(*ev), GFP_ATOMIC);
672 	if (!ev) {
673 		warn("Link event allocation failure\n");
674 		return;
675 	}
676 	ev->addr = l_ptr->addr;
677 	ev->up = up;
678 	ev->fcn = fcn;
679 	memcpy(ev->name, l_ptr->name, TIPC_MAX_LINK_NAME);
680 	tipc_k_signal((Handler)link_recv_event, (unsigned long)ev);
681 }
682 
683 #else
684 
685 #define link_send_event(fcn, l_ptr, up) do { } while (0)
686 
687 #endif
688 
689 void tipc_link_reset(struct link *l_ptr)
690 {
691 	struct sk_buff *buf;
692 	u32 prev_state = l_ptr->state;
693 	u32 checkpoint = l_ptr->next_in_no;
694 
695 	msg_set_session(l_ptr->pmsg, msg_session(l_ptr->pmsg) + 1);
696 
697         /* Link is down, accept any session: */
698 	l_ptr->peer_session = 0;
699 
700         /* Prepare for max packet size negotiation */
701 	link_init_max_pkt(l_ptr);
702 
703 	l_ptr->state = RESET_UNKNOWN;
704 	dbg_link_state("Resetting Link\n");
705 
706 	if ((prev_state == RESET_UNKNOWN) || (prev_state == RESET_RESET))
707 		return;
708 
709 	tipc_node_link_down(l_ptr->owner, l_ptr);
710 	tipc_bearer_remove_dest(l_ptr->b_ptr, l_ptr->addr);
711 #if 0
712 	tipc_printf(TIPC_CONS, "\nReset link <%s>\n", l_ptr->name);
713 	dbg_link_dump();
714 #endif
715 	if (tipc_node_has_active_links(l_ptr->owner) &&
716 	    l_ptr->owner->permit_changeover) {
717 		l_ptr->reset_checkpoint = checkpoint;
718 		l_ptr->exp_msg_count = START_CHANGEOVER;
719 	}
720 
721 	/* Clean up all queues: */
722 
723 	link_release_outqueue(l_ptr);
724 	buf_discard(l_ptr->proto_msg_queue);
725 	l_ptr->proto_msg_queue = NULL;
726 	buf = l_ptr->oldest_deferred_in;
727 	while (buf) {
728 		struct sk_buff *next = buf->next;
729 		buf_discard(buf);
730 		buf = next;
731 	}
732 	if (!list_empty(&l_ptr->waiting_ports))
733 		tipc_link_wakeup_ports(l_ptr, 1);
734 
735 	l_ptr->retransm_queue_head = 0;
736 	l_ptr->retransm_queue_size = 0;
737 	l_ptr->last_out = NULL;
738 	l_ptr->first_out = NULL;
739 	l_ptr->next_out = NULL;
740 	l_ptr->unacked_window = 0;
741 	l_ptr->checkpoint = 1;
742 	l_ptr->next_out_no = 1;
743 	l_ptr->deferred_inqueue_sz = 0;
744 	l_ptr->oldest_deferred_in = NULL;
745 	l_ptr->newest_deferred_in = NULL;
746 	l_ptr->fsm_msg_cnt = 0;
747 	l_ptr->stale_count = 0;
748 	link_reset_statistics(l_ptr);
749 
750 	link_send_event(tipc_cfg_link_event, l_ptr, 0);
751 	if (!in_own_cluster(l_ptr->addr))
752 		link_send_event(tipc_disc_link_event, l_ptr, 0);
753 }
754 
755 
756 static void link_activate(struct link *l_ptr)
757 {
758 	l_ptr->next_in_no = 1;
759 	tipc_node_link_up(l_ptr->owner, l_ptr);
760 	tipc_bearer_add_dest(l_ptr->b_ptr, l_ptr->addr);
761 	link_send_event(tipc_cfg_link_event, l_ptr, 1);
762 	if (!in_own_cluster(l_ptr->addr))
763 		link_send_event(tipc_disc_link_event, l_ptr, 1);
764 }
765 
766 /**
767  * link_state_event - link finite state machine
768  * @l_ptr: pointer to link
769  * @event: state machine event to process
770  */
771 
772 static void link_state_event(struct link *l_ptr, unsigned event)
773 {
774 	struct link *other;
775 	u32 cont_intv = l_ptr->continuity_interval;
776 
777 	if (!l_ptr->started && (event != STARTING_EVT))
778 		return;		/* Not yet. */
779 
780 	if (link_blocked(l_ptr)) {
781 		if (event == TIMEOUT_EVT) {
782 			link_set_timer(l_ptr, cont_intv);
783 		}
784 		return;	  /* Changeover going on */
785 	}
786 	dbg_link("STATE_EV: <%s> ", l_ptr->name);
787 
788 	switch (l_ptr->state) {
789 	case WORKING_WORKING:
790 		dbg_link("WW/");
791 		switch (event) {
792 		case TRAFFIC_MSG_EVT:
793 			dbg_link("TRF-");
794 			/* fall through */
795 		case ACTIVATE_MSG:
796 			dbg_link("ACT\n");
797 			break;
798 		case TIMEOUT_EVT:
799 			dbg_link("TIM ");
800 			if (l_ptr->next_in_no != l_ptr->checkpoint) {
801 				l_ptr->checkpoint = l_ptr->next_in_no;
802 				if (tipc_bclink_acks_missing(l_ptr->owner)) {
803 					tipc_link_send_proto_msg(l_ptr, STATE_MSG,
804 								 0, 0, 0, 0, 0);
805 					l_ptr->fsm_msg_cnt++;
806 				} else if (l_ptr->max_pkt < l_ptr->max_pkt_target) {
807 					tipc_link_send_proto_msg(l_ptr, STATE_MSG,
808 								 1, 0, 0, 0, 0);
809 					l_ptr->fsm_msg_cnt++;
810 				}
811 				link_set_timer(l_ptr, cont_intv);
812 				break;
813 			}
814 			dbg_link(" -> WU\n");
815 			l_ptr->state = WORKING_UNKNOWN;
816 			l_ptr->fsm_msg_cnt = 0;
817 			tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
818 			l_ptr->fsm_msg_cnt++;
819 			link_set_timer(l_ptr, cont_intv / 4);
820 			break;
821 		case RESET_MSG:
822 			dbg_link("RES -> RR\n");
823 			tipc_link_reset(l_ptr);
824 			l_ptr->state = RESET_RESET;
825 			l_ptr->fsm_msg_cnt = 0;
826 			tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
827 			l_ptr->fsm_msg_cnt++;
828 			link_set_timer(l_ptr, cont_intv);
829 			break;
830 		default:
831 			err("Unknown link event %u in WW state\n", event);
832 		}
833 		break;
834 	case WORKING_UNKNOWN:
835 		dbg_link("WU/");
836 		switch (event) {
837 		case TRAFFIC_MSG_EVT:
838 			dbg_link("TRF-");
839 		case ACTIVATE_MSG:
840 			dbg_link("ACT -> WW\n");
841 			l_ptr->state = WORKING_WORKING;
842 			l_ptr->fsm_msg_cnt = 0;
843 			link_set_timer(l_ptr, cont_intv);
844 			break;
845 		case RESET_MSG:
846 			dbg_link("RES -> RR\n");
847 			tipc_link_reset(l_ptr);
848 			l_ptr->state = RESET_RESET;
849 			l_ptr->fsm_msg_cnt = 0;
850 			tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
851 			l_ptr->fsm_msg_cnt++;
852 			link_set_timer(l_ptr, cont_intv);
853 			break;
854 		case TIMEOUT_EVT:
855 			dbg_link("TIM ");
856 			if (l_ptr->next_in_no != l_ptr->checkpoint) {
857 				dbg_link("-> WW \n");
858 				l_ptr->state = WORKING_WORKING;
859 				l_ptr->fsm_msg_cnt = 0;
860 				l_ptr->checkpoint = l_ptr->next_in_no;
861 				if (tipc_bclink_acks_missing(l_ptr->owner)) {
862 					tipc_link_send_proto_msg(l_ptr, STATE_MSG,
863 								 0, 0, 0, 0, 0);
864 					l_ptr->fsm_msg_cnt++;
865 				}
866 				link_set_timer(l_ptr, cont_intv);
867 			} else if (l_ptr->fsm_msg_cnt < l_ptr->abort_limit) {
868 				dbg_link("Probing %u/%u,timer = %u ms)\n",
869 					 l_ptr->fsm_msg_cnt, l_ptr->abort_limit,
870 					 cont_intv / 4);
871 				tipc_link_send_proto_msg(l_ptr, STATE_MSG,
872 							 1, 0, 0, 0, 0);
873 				l_ptr->fsm_msg_cnt++;
874 				link_set_timer(l_ptr, cont_intv / 4);
875 			} else {	/* Link has failed */
876 				dbg_link("-> RU (%u probes unanswered)\n",
877 					 l_ptr->fsm_msg_cnt);
878 				tipc_link_reset(l_ptr);
879 				l_ptr->state = RESET_UNKNOWN;
880 				l_ptr->fsm_msg_cnt = 0;
881 				tipc_link_send_proto_msg(l_ptr, RESET_MSG,
882 							 0, 0, 0, 0, 0);
883 				l_ptr->fsm_msg_cnt++;
884 				link_set_timer(l_ptr, cont_intv);
885 			}
886 			break;
887 		default:
888 			err("Unknown link event %u in WU state\n", event);
889 		}
890 		break;
891 	case RESET_UNKNOWN:
892 		dbg_link("RU/");
893 		switch (event) {
894 		case TRAFFIC_MSG_EVT:
895 			dbg_link("TRF-\n");
896 			break;
897 		case ACTIVATE_MSG:
898 			other = l_ptr->owner->active_links[0];
899 			if (other && link_working_unknown(other)) {
900 				dbg_link("ACT\n");
901 				break;
902 			}
903 			dbg_link("ACT -> WW\n");
904 			l_ptr->state = WORKING_WORKING;
905 			l_ptr->fsm_msg_cnt = 0;
906 			link_activate(l_ptr);
907 			tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
908 			l_ptr->fsm_msg_cnt++;
909 			link_set_timer(l_ptr, cont_intv);
910 			break;
911 		case RESET_MSG:
912 			dbg_link("RES \n");
913 			dbg_link(" -> RR\n");
914 			l_ptr->state = RESET_RESET;
915 			l_ptr->fsm_msg_cnt = 0;
916 			tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 1, 0, 0, 0, 0);
917 			l_ptr->fsm_msg_cnt++;
918 			link_set_timer(l_ptr, cont_intv);
919 			break;
920 		case STARTING_EVT:
921 			dbg_link("START-");
922 			l_ptr->started = 1;
923 			/* fall through */
924 		case TIMEOUT_EVT:
925 			dbg_link("TIM \n");
926 			tipc_link_send_proto_msg(l_ptr, RESET_MSG, 0, 0, 0, 0, 0);
927 			l_ptr->fsm_msg_cnt++;
928 			link_set_timer(l_ptr, cont_intv);
929 			break;
930 		default:
931 			err("Unknown link event %u in RU state\n", event);
932 		}
933 		break;
934 	case RESET_RESET:
935 		dbg_link("RR/ ");
936 		switch (event) {
937 		case TRAFFIC_MSG_EVT:
938 			dbg_link("TRF-");
939 			/* fall through */
940 		case ACTIVATE_MSG:
941 			other = l_ptr->owner->active_links[0];
942 			if (other && link_working_unknown(other)) {
943 				dbg_link("ACT\n");
944 				break;
945 			}
946 			dbg_link("ACT -> WW\n");
947 			l_ptr->state = WORKING_WORKING;
948 			l_ptr->fsm_msg_cnt = 0;
949 			link_activate(l_ptr);
950 			tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
951 			l_ptr->fsm_msg_cnt++;
952 			link_set_timer(l_ptr, cont_intv);
953 			break;
954 		case RESET_MSG:
955 			dbg_link("RES\n");
956 			break;
957 		case TIMEOUT_EVT:
958 			dbg_link("TIM\n");
959 			tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
960 			l_ptr->fsm_msg_cnt++;
961 			link_set_timer(l_ptr, cont_intv);
962 			dbg_link("fsm_msg_cnt %u\n", l_ptr->fsm_msg_cnt);
963 			break;
964 		default:
965 			err("Unknown link event %u in RR state\n", event);
966 		}
967 		break;
968 	default:
969 		err("Unknown link state %u/%u\n", l_ptr->state, event);
970 	}
971 }
972 
973 /*
974  * link_bundle_buf(): Append contents of a buffer to
975  * the tail of an existing one.
976  */
977 
978 static int link_bundle_buf(struct link *l_ptr,
979 			   struct sk_buff *bundler,
980 			   struct sk_buff *buf)
981 {
982 	struct tipc_msg *bundler_msg = buf_msg(bundler);
983 	struct tipc_msg *msg = buf_msg(buf);
984 	u32 size = msg_size(msg);
985 	u32 to_pos = align(msg_size(bundler_msg));
986 	u32 rest = link_max_pkt(l_ptr) - to_pos;
987 
988 	if (msg_user(bundler_msg) != MSG_BUNDLER)
989 		return 0;
990 	if (msg_type(bundler_msg) != OPEN_MSG)
991 		return 0;
992 	if (rest < align(size))
993 		return 0;
994 
995 	skb_put(bundler, (to_pos - msg_size(bundler_msg)) + size);
996 	memcpy(bundler->data + to_pos, buf->data, size);
997 	msg_set_size(bundler_msg, to_pos + size);
998 	msg_set_msgcnt(bundler_msg, msg_msgcnt(bundler_msg) + 1);
999 	dbg("Packed msg # %u(%u octets) into pos %u in buf(#%u)\n",
1000 	    msg_msgcnt(bundler_msg), size, to_pos, msg_seqno(bundler_msg));
1001 	msg_dbg(msg, "PACKD:");
1002 	buf_discard(buf);
1003 	l_ptr->stats.sent_bundled++;
1004 	return 1;
1005 }
1006 
1007 static inline void link_add_to_outqueue(struct link *l_ptr,
1008 					struct sk_buff *buf,
1009 					struct tipc_msg *msg)
1010 {
1011 	u32 ack = mod(l_ptr->next_in_no - 1);
1012 	u32 seqno = mod(l_ptr->next_out_no++);
1013 
1014 	msg_set_word(msg, 2, ((ack << 16) | seqno));
1015 	msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1016 	buf->next = NULL;
1017 	if (l_ptr->first_out) {
1018 		l_ptr->last_out->next = buf;
1019 		l_ptr->last_out = buf;
1020 	} else
1021 		l_ptr->first_out = l_ptr->last_out = buf;
1022 	l_ptr->out_queue_size++;
1023 }
1024 
1025 /*
1026  * tipc_link_send_buf() is the 'full path' for messages, called from
1027  * inside TIPC when the 'fast path' in tipc_send_buf
1028  * has failed, and from link_send()
1029  */
1030 
1031 int tipc_link_send_buf(struct link *l_ptr, struct sk_buff *buf)
1032 {
1033 	struct tipc_msg *msg = buf_msg(buf);
1034 	u32 size = msg_size(msg);
1035 	u32 dsz = msg_data_sz(msg);
1036 	u32 queue_size = l_ptr->out_queue_size;
1037 	u32 imp = msg_tot_importance(msg);
1038 	u32 queue_limit = l_ptr->queue_limit[imp];
1039 	u32 max_packet = link_max_pkt(l_ptr);
1040 
1041 	msg_set_prevnode(msg, tipc_own_addr);	/* If routed message */
1042 
1043 	/* Match msg importance against queue limits: */
1044 
1045 	if (unlikely(queue_size >= queue_limit)) {
1046 		if (imp <= TIPC_CRITICAL_IMPORTANCE) {
1047 			return link_schedule_port(l_ptr, msg_origport(msg),
1048 						  size);
1049 		}
1050 		msg_dbg(msg, "TIPC: Congestion, throwing away\n");
1051 		buf_discard(buf);
1052 		if (imp > CONN_MANAGER) {
1053 			warn("Resetting <%s>, send queue full", l_ptr->name);
1054 			tipc_link_reset(l_ptr);
1055 		}
1056 		return dsz;
1057 	}
1058 
1059 	/* Fragmentation needed ? */
1060 
1061 	if (size > max_packet)
1062 		return tipc_link_send_long_buf(l_ptr, buf);
1063 
1064 	/* Packet can be queued or sent: */
1065 
1066 	if (queue_size > l_ptr->stats.max_queue_sz)
1067 		l_ptr->stats.max_queue_sz = queue_size;
1068 
1069 	if (likely(!tipc_bearer_congested(l_ptr->b_ptr, l_ptr) &&
1070 		   !link_congested(l_ptr))) {
1071 		link_add_to_outqueue(l_ptr, buf, msg);
1072 
1073 		if (likely(tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr))) {
1074 			l_ptr->unacked_window = 0;
1075 		} else {
1076 			tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
1077 			l_ptr->stats.bearer_congs++;
1078 			l_ptr->next_out = buf;
1079 		}
1080 		return dsz;
1081 	}
1082 	/* Congestion: can message be bundled ?: */
1083 
1084 	if ((msg_user(msg) != CHANGEOVER_PROTOCOL) &&
1085 	    (msg_user(msg) != MSG_FRAGMENTER)) {
1086 
1087 		/* Try adding message to an existing bundle */
1088 
1089 		if (l_ptr->next_out &&
1090 		    link_bundle_buf(l_ptr, l_ptr->last_out, buf)) {
1091 			tipc_bearer_resolve_congestion(l_ptr->b_ptr, l_ptr);
1092 			return dsz;
1093 		}
1094 
1095 		/* Try creating a new bundle */
1096 
1097 		if (size <= max_packet * 2 / 3) {
1098 			struct sk_buff *bundler = buf_acquire(max_packet);
1099 			struct tipc_msg bundler_hdr;
1100 
1101 			if (bundler) {
1102 				msg_init(&bundler_hdr, MSG_BUNDLER, OPEN_MSG,
1103 					 TIPC_OK, INT_H_SIZE, l_ptr->addr);
1104 				memcpy(bundler->data, (unchar *)&bundler_hdr,
1105 				       INT_H_SIZE);
1106 				skb_trim(bundler, INT_H_SIZE);
1107 				link_bundle_buf(l_ptr, bundler, buf);
1108 				buf = bundler;
1109 				msg = buf_msg(buf);
1110 				l_ptr->stats.sent_bundles++;
1111 			}
1112 		}
1113 	}
1114 	if (!l_ptr->next_out)
1115 		l_ptr->next_out = buf;
1116 	link_add_to_outqueue(l_ptr, buf, msg);
1117 	tipc_bearer_resolve_congestion(l_ptr->b_ptr, l_ptr);
1118 	return dsz;
1119 }
1120 
1121 /*
1122  * tipc_link_send(): same as tipc_link_send_buf(), but the link to use has
1123  * not been selected yet, and the the owner node is not locked
1124  * Called by TIPC internal users, e.g. the name distributor
1125  */
1126 
1127 int tipc_link_send(struct sk_buff *buf, u32 dest, u32 selector)
1128 {
1129 	struct link *l_ptr;
1130 	struct node *n_ptr;
1131 	int res = -ELINKCONG;
1132 
1133 	read_lock_bh(&tipc_net_lock);
1134 	n_ptr = tipc_node_select(dest, selector);
1135 	if (n_ptr) {
1136 		tipc_node_lock(n_ptr);
1137 		l_ptr = n_ptr->active_links[selector & 1];
1138 		dbg("tipc_link_send: found link %x for dest %x\n", l_ptr, dest);
1139 		if (l_ptr) {
1140 			res = tipc_link_send_buf(l_ptr, buf);
1141 		}
1142 		tipc_node_unlock(n_ptr);
1143 	} else {
1144 		dbg("Attempt to send msg to unknown node:\n");
1145 		msg_dbg(buf_msg(buf),">>>");
1146 		buf_discard(buf);
1147 	}
1148 	read_unlock_bh(&tipc_net_lock);
1149 	return res;
1150 }
1151 
1152 /*
1153  * link_send_buf_fast: Entry for data messages where the
1154  * destination link is known and the header is complete,
1155  * inclusive total message length. Very time critical.
1156  * Link is locked. Returns user data length.
1157  */
1158 
1159 static inline int link_send_buf_fast(struct link *l_ptr, struct sk_buff *buf,
1160 				     u32 *used_max_pkt)
1161 {
1162 	struct tipc_msg *msg = buf_msg(buf);
1163 	int res = msg_data_sz(msg);
1164 
1165 	if (likely(!link_congested(l_ptr))) {
1166 		if (likely(msg_size(msg) <= link_max_pkt(l_ptr))) {
1167 			if (likely(list_empty(&l_ptr->b_ptr->cong_links))) {
1168 				link_add_to_outqueue(l_ptr, buf, msg);
1169 				if (likely(tipc_bearer_send(l_ptr->b_ptr, buf,
1170 							    &l_ptr->media_addr))) {
1171 					l_ptr->unacked_window = 0;
1172 					msg_dbg(msg,"SENT_FAST:");
1173 					return res;
1174 				}
1175 				dbg("failed sent fast...\n");
1176 				tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
1177 				l_ptr->stats.bearer_congs++;
1178 				l_ptr->next_out = buf;
1179 				return res;
1180 			}
1181 		}
1182 		else
1183 			*used_max_pkt = link_max_pkt(l_ptr);
1184 	}
1185 	return tipc_link_send_buf(l_ptr, buf);  /* All other cases */
1186 }
1187 
1188 /*
1189  * tipc_send_buf_fast: Entry for data messages where the
1190  * destination node is known and the header is complete,
1191  * inclusive total message length.
1192  * Returns user data length.
1193  */
1194 int tipc_send_buf_fast(struct sk_buff *buf, u32 destnode)
1195 {
1196 	struct link *l_ptr;
1197 	struct node *n_ptr;
1198 	int res;
1199 	u32 selector = msg_origport(buf_msg(buf)) & 1;
1200 	u32 dummy;
1201 
1202 	if (destnode == tipc_own_addr)
1203 		return tipc_port_recv_msg(buf);
1204 
1205 	read_lock_bh(&tipc_net_lock);
1206 	n_ptr = tipc_node_select(destnode, selector);
1207 	if (likely(n_ptr)) {
1208 		tipc_node_lock(n_ptr);
1209 		l_ptr = n_ptr->active_links[selector];
1210 		dbg("send_fast: buf %x selected %x, destnode = %x\n",
1211 		    buf, l_ptr, destnode);
1212 		if (likely(l_ptr)) {
1213 			res = link_send_buf_fast(l_ptr, buf, &dummy);
1214 			tipc_node_unlock(n_ptr);
1215 			read_unlock_bh(&tipc_net_lock);
1216 			return res;
1217 		}
1218 		tipc_node_unlock(n_ptr);
1219 	}
1220 	read_unlock_bh(&tipc_net_lock);
1221 	res = msg_data_sz(buf_msg(buf));
1222 	tipc_reject_msg(buf, TIPC_ERR_NO_NODE);
1223 	return res;
1224 }
1225 
1226 
1227 /*
1228  * tipc_link_send_sections_fast: Entry for messages where the
1229  * destination processor is known and the header is complete,
1230  * except for total message length.
1231  * Returns user data length or errno.
1232  */
1233 int tipc_link_send_sections_fast(struct port *sender,
1234 				 struct iovec const *msg_sect,
1235 				 const u32 num_sect,
1236 				 u32 destaddr)
1237 {
1238 	struct tipc_msg *hdr = &sender->publ.phdr;
1239 	struct link *l_ptr;
1240 	struct sk_buff *buf;
1241 	struct node *node;
1242 	int res;
1243 	u32 selector = msg_origport(hdr) & 1;
1244 
1245 	assert(destaddr != tipc_own_addr);
1246 
1247 again:
1248 	/*
1249 	 * Try building message using port's max_pkt hint.
1250 	 * (Must not hold any locks while building message.)
1251 	 */
1252 
1253 	res = msg_build(hdr, msg_sect, num_sect, sender->max_pkt,
1254 			!sender->user_port, &buf);
1255 
1256 	read_lock_bh(&tipc_net_lock);
1257 	node = tipc_node_select(destaddr, selector);
1258 	if (likely(node)) {
1259 		tipc_node_lock(node);
1260 		l_ptr = node->active_links[selector];
1261 		if (likely(l_ptr)) {
1262 			if (likely(buf)) {
1263 				res = link_send_buf_fast(l_ptr, buf,
1264 							 &sender->max_pkt);
1265 				if (unlikely(res < 0))
1266 					buf_discard(buf);
1267 exit:
1268 				tipc_node_unlock(node);
1269 				read_unlock_bh(&tipc_net_lock);
1270 				return res;
1271 			}
1272 
1273 			/* Exit if build request was invalid */
1274 
1275 			if (unlikely(res < 0))
1276 				goto exit;
1277 
1278 			/* Exit if link (or bearer) is congested */
1279 
1280 			if (link_congested(l_ptr) ||
1281 			    !list_empty(&l_ptr->b_ptr->cong_links)) {
1282 				res = link_schedule_port(l_ptr,
1283 							 sender->publ.ref, res);
1284 				goto exit;
1285 			}
1286 
1287 			/*
1288 			 * Message size exceeds max_pkt hint; update hint,
1289 			 * then re-try fast path or fragment the message
1290 			 */
1291 
1292 			sender->max_pkt = link_max_pkt(l_ptr);
1293 			tipc_node_unlock(node);
1294 			read_unlock_bh(&tipc_net_lock);
1295 
1296 
1297 			if ((msg_hdr_sz(hdr) + res) <= sender->max_pkt)
1298 				goto again;
1299 
1300 			return link_send_sections_long(sender, msg_sect,
1301 						       num_sect, destaddr);
1302 		}
1303 		tipc_node_unlock(node);
1304 	}
1305 	read_unlock_bh(&tipc_net_lock);
1306 
1307 	/* Couldn't find a link to the destination node */
1308 
1309 	if (buf)
1310 		return tipc_reject_msg(buf, TIPC_ERR_NO_NODE);
1311 	if (res >= 0)
1312 		return tipc_port_reject_sections(sender, hdr, msg_sect, num_sect,
1313 						 TIPC_ERR_NO_NODE);
1314 	return res;
1315 }
1316 
1317 /*
1318  * link_send_sections_long(): Entry for long messages where the
1319  * destination node is known and the header is complete,
1320  * inclusive total message length.
1321  * Link and bearer congestion status have been checked to be ok,
1322  * and are ignored if they change.
1323  *
1324  * Note that fragments do not use the full link MTU so that they won't have
1325  * to undergo refragmentation if link changeover causes them to be sent
1326  * over another link with an additional tunnel header added as prefix.
1327  * (Refragmentation will still occur if the other link has a smaller MTU.)
1328  *
1329  * Returns user data length or errno.
1330  */
1331 static int link_send_sections_long(struct port *sender,
1332 				   struct iovec const *msg_sect,
1333 				   u32 num_sect,
1334 				   u32 destaddr)
1335 {
1336 	struct link *l_ptr;
1337 	struct node *node;
1338 	struct tipc_msg *hdr = &sender->publ.phdr;
1339 	u32 dsz = msg_data_sz(hdr);
1340 	u32 max_pkt,fragm_sz,rest;
1341 	struct tipc_msg fragm_hdr;
1342 	struct sk_buff *buf,*buf_chain,*prev;
1343 	u32 fragm_crs,fragm_rest,hsz,sect_rest;
1344 	const unchar *sect_crs;
1345 	int curr_sect;
1346 	u32 fragm_no;
1347 
1348 again:
1349 	fragm_no = 1;
1350 	max_pkt = sender->max_pkt - INT_H_SIZE;
1351 		/* leave room for tunnel header in case of link changeover */
1352 	fragm_sz = max_pkt - INT_H_SIZE;
1353 		/* leave room for fragmentation header in each fragment */
1354 	rest = dsz;
1355 	fragm_crs = 0;
1356 	fragm_rest = 0;
1357 	sect_rest = 0;
1358 	sect_crs = 0;
1359 	curr_sect = -1;
1360 
1361 	/* Prepare reusable fragment header: */
1362 
1363 	msg_dbg(hdr, ">FRAGMENTING>");
1364 	msg_init(&fragm_hdr, MSG_FRAGMENTER, FIRST_FRAGMENT,
1365 		 TIPC_OK, INT_H_SIZE, msg_destnode(hdr));
1366 	msg_set_link_selector(&fragm_hdr, sender->publ.ref);
1367 	msg_set_size(&fragm_hdr, max_pkt);
1368 	msg_set_fragm_no(&fragm_hdr, 1);
1369 
1370 	/* Prepare header of first fragment: */
1371 
1372 	buf_chain = buf = buf_acquire(max_pkt);
1373 	if (!buf)
1374 		return -ENOMEM;
1375 	buf->next = NULL;
1376 	memcpy(buf->data, (unchar *)&fragm_hdr, INT_H_SIZE);
1377 	hsz = msg_hdr_sz(hdr);
1378 	memcpy(buf->data + INT_H_SIZE, (unchar *)hdr, hsz);
1379 	msg_dbg(buf_msg(buf), ">BUILD>");
1380 
1381 	/* Chop up message: */
1382 
1383 	fragm_crs = INT_H_SIZE + hsz;
1384 	fragm_rest = fragm_sz - hsz;
1385 
1386 	do {		/* For all sections */
1387 		u32 sz;
1388 
1389 		if (!sect_rest) {
1390 			sect_rest = msg_sect[++curr_sect].iov_len;
1391 			sect_crs = (const unchar *)msg_sect[curr_sect].iov_base;
1392 		}
1393 
1394 		if (sect_rest < fragm_rest)
1395 			sz = sect_rest;
1396 		else
1397 			sz = fragm_rest;
1398 
1399 		if (likely(!sender->user_port)) {
1400 			if (copy_from_user(buf->data + fragm_crs, sect_crs, sz)) {
1401 error:
1402 				for (; buf_chain; buf_chain = buf) {
1403 					buf = buf_chain->next;
1404 					buf_discard(buf_chain);
1405 				}
1406 				return -EFAULT;
1407 			}
1408 		} else
1409 			memcpy(buf->data + fragm_crs, sect_crs, sz);
1410 
1411 		sect_crs += sz;
1412 		sect_rest -= sz;
1413 		fragm_crs += sz;
1414 		fragm_rest -= sz;
1415 		rest -= sz;
1416 
1417 		if (!fragm_rest && rest) {
1418 
1419 			/* Initiate new fragment: */
1420 			if (rest <= fragm_sz) {
1421 				fragm_sz = rest;
1422 				msg_set_type(&fragm_hdr,LAST_FRAGMENT);
1423 			} else {
1424 				msg_set_type(&fragm_hdr, FRAGMENT);
1425 			}
1426 			msg_set_size(&fragm_hdr, fragm_sz + INT_H_SIZE);
1427 			msg_set_fragm_no(&fragm_hdr, ++fragm_no);
1428 			prev = buf;
1429 			buf = buf_acquire(fragm_sz + INT_H_SIZE);
1430 			if (!buf)
1431 				goto error;
1432 
1433 			buf->next = NULL;
1434 			prev->next = buf;
1435 			memcpy(buf->data, (unchar *)&fragm_hdr, INT_H_SIZE);
1436 			fragm_crs = INT_H_SIZE;
1437 			fragm_rest = fragm_sz;
1438 			msg_dbg(buf_msg(buf),"  >BUILD>");
1439 		}
1440 	}
1441 	while (rest > 0);
1442 
1443 	/*
1444 	 * Now we have a buffer chain. Select a link and check
1445 	 * that packet size is still OK
1446 	 */
1447 	node = tipc_node_select(destaddr, sender->publ.ref & 1);
1448 	if (likely(node)) {
1449 		tipc_node_lock(node);
1450 		l_ptr = node->active_links[sender->publ.ref & 1];
1451 		if (!l_ptr) {
1452 			tipc_node_unlock(node);
1453 			goto reject;
1454 		}
1455 		if (link_max_pkt(l_ptr) < max_pkt) {
1456 			sender->max_pkt = link_max_pkt(l_ptr);
1457 			tipc_node_unlock(node);
1458 			for (; buf_chain; buf_chain = buf) {
1459 				buf = buf_chain->next;
1460 				buf_discard(buf_chain);
1461 			}
1462 			goto again;
1463 		}
1464 	} else {
1465 reject:
1466 		for (; buf_chain; buf_chain = buf) {
1467 			buf = buf_chain->next;
1468 			buf_discard(buf_chain);
1469 		}
1470 		return tipc_port_reject_sections(sender, hdr, msg_sect, num_sect,
1471 						 TIPC_ERR_NO_NODE);
1472 	}
1473 
1474 	/* Append whole chain to send queue: */
1475 
1476 	buf = buf_chain;
1477 	l_ptr->long_msg_seq_no = mod(l_ptr->long_msg_seq_no + 1);
1478 	if (!l_ptr->next_out)
1479 		l_ptr->next_out = buf_chain;
1480 	l_ptr->stats.sent_fragmented++;
1481 	while (buf) {
1482 		struct sk_buff *next = buf->next;
1483 		struct tipc_msg *msg = buf_msg(buf);
1484 
1485 		l_ptr->stats.sent_fragments++;
1486 		msg_set_long_msgno(msg, l_ptr->long_msg_seq_no);
1487 		link_add_to_outqueue(l_ptr, buf, msg);
1488 		msg_dbg(msg, ">ADD>");
1489 		buf = next;
1490 	}
1491 
1492 	/* Send it, if possible: */
1493 
1494 	tipc_link_push_queue(l_ptr);
1495 	tipc_node_unlock(node);
1496 	return dsz;
1497 }
1498 
1499 /*
1500  * tipc_link_push_packet: Push one unsent packet to the media
1501  */
1502 u32 tipc_link_push_packet(struct link *l_ptr)
1503 {
1504 	struct sk_buff *buf = l_ptr->first_out;
1505 	u32 r_q_size = l_ptr->retransm_queue_size;
1506 	u32 r_q_head = l_ptr->retransm_queue_head;
1507 
1508 	/* Step to position where retransmission failed, if any,    */
1509 	/* consider that buffers may have been released in meantime */
1510 
1511 	if (r_q_size && buf) {
1512 		u32 last = lesser(mod(r_q_head + r_q_size),
1513 				  link_last_sent(l_ptr));
1514 		u32 first = msg_seqno(buf_msg(buf));
1515 
1516 		while (buf && less(first, r_q_head)) {
1517 			first = mod(first + 1);
1518 			buf = buf->next;
1519 		}
1520 		l_ptr->retransm_queue_head = r_q_head = first;
1521 		l_ptr->retransm_queue_size = r_q_size = mod(last - first);
1522 	}
1523 
1524 	/* Continue retransmission now, if there is anything: */
1525 
1526 	if (r_q_size && buf && !skb_cloned(buf)) {
1527 		msg_set_ack(buf_msg(buf), mod(l_ptr->next_in_no - 1));
1528 		msg_set_bcast_ack(buf_msg(buf), l_ptr->owner->bclink.last_in);
1529 		if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1530 			msg_dbg(buf_msg(buf), ">DEF-RETR>");
1531 			l_ptr->retransm_queue_head = mod(++r_q_head);
1532 			l_ptr->retransm_queue_size = --r_q_size;
1533 			l_ptr->stats.retransmitted++;
1534 			return TIPC_OK;
1535 		} else {
1536 			l_ptr->stats.bearer_congs++;
1537 			msg_dbg(buf_msg(buf), "|>DEF-RETR>");
1538 			return PUSH_FAILED;
1539 		}
1540 	}
1541 
1542 	/* Send deferred protocol message, if any: */
1543 
1544 	buf = l_ptr->proto_msg_queue;
1545 	if (buf) {
1546 		msg_set_ack(buf_msg(buf), mod(l_ptr->next_in_no - 1));
1547 		msg_set_bcast_ack(buf_msg(buf),l_ptr->owner->bclink.last_in);
1548 		if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1549 			msg_dbg(buf_msg(buf), ">DEF-PROT>");
1550 			l_ptr->unacked_window = 0;
1551 			buf_discard(buf);
1552 			l_ptr->proto_msg_queue = 0;
1553 			return TIPC_OK;
1554 		} else {
1555 			msg_dbg(buf_msg(buf), "|>DEF-PROT>");
1556 			l_ptr->stats.bearer_congs++;
1557 			return PUSH_FAILED;
1558 		}
1559 	}
1560 
1561 	/* Send one deferred data message, if send window not full: */
1562 
1563 	buf = l_ptr->next_out;
1564 	if (buf) {
1565 		struct tipc_msg *msg = buf_msg(buf);
1566 		u32 next = msg_seqno(msg);
1567 		u32 first = msg_seqno(buf_msg(l_ptr->first_out));
1568 
1569 		if (mod(next - first) < l_ptr->queue_limit[0]) {
1570 			msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1571 			msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1572 			if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1573 				if (msg_user(msg) == MSG_BUNDLER)
1574 					msg_set_type(msg, CLOSED_MSG);
1575 				msg_dbg(msg, ">PUSH-DATA>");
1576 				l_ptr->next_out = buf->next;
1577 				return TIPC_OK;
1578 			} else {
1579 				msg_dbg(msg, "|PUSH-DATA|");
1580 				l_ptr->stats.bearer_congs++;
1581 				return PUSH_FAILED;
1582 			}
1583 		}
1584 	}
1585 	return PUSH_FINISHED;
1586 }
1587 
1588 /*
1589  * push_queue(): push out the unsent messages of a link where
1590  *               congestion has abated. Node is locked
1591  */
1592 void tipc_link_push_queue(struct link *l_ptr)
1593 {
1594 	u32 res;
1595 
1596 	if (tipc_bearer_congested(l_ptr->b_ptr, l_ptr))
1597 		return;
1598 
1599 	do {
1600 		res = tipc_link_push_packet(l_ptr);
1601 	}
1602 	while (res == TIPC_OK);
1603 	if (res == PUSH_FAILED)
1604 		tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
1605 }
1606 
1607 void tipc_link_retransmit(struct link *l_ptr, struct sk_buff *buf,
1608 			  u32 retransmits)
1609 {
1610 	struct tipc_msg *msg;
1611 
1612 	dbg("Retransmitting %u in link %x\n", retransmits, l_ptr);
1613 
1614 	if (tipc_bearer_congested(l_ptr->b_ptr, l_ptr) && buf && !skb_cloned(buf)) {
1615 		msg_dbg(buf_msg(buf), ">NO_RETR->BCONG>");
1616 		dbg_print_link(l_ptr, "   ");
1617 		l_ptr->retransm_queue_head = msg_seqno(buf_msg(buf));
1618 		l_ptr->retransm_queue_size = retransmits;
1619 		return;
1620 	}
1621 	while (retransmits && (buf != l_ptr->next_out) && buf && !skb_cloned(buf)) {
1622 		msg = buf_msg(buf);
1623 		msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1624 		msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1625 		if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1626                         /* Catch if retransmissions fail repeatedly: */
1627                         if (l_ptr->last_retransmitted == msg_seqno(msg)) {
1628                                 if (++l_ptr->stale_count > 100) {
1629                                         tipc_msg_print(TIPC_CONS, buf_msg(buf), ">RETR>");
1630                                         info("...Retransmitted %u times\n",
1631 					     l_ptr->stale_count);
1632                                         link_print(l_ptr, TIPC_CONS, "Resetting Link\n");;
1633                                         tipc_link_reset(l_ptr);
1634                                         break;
1635                                 }
1636                         } else {
1637                                 l_ptr->stale_count = 0;
1638                         }
1639                         l_ptr->last_retransmitted = msg_seqno(msg);
1640 
1641 			msg_dbg(buf_msg(buf), ">RETR>");
1642 			buf = buf->next;
1643 			retransmits--;
1644 			l_ptr->stats.retransmitted++;
1645 		} else {
1646 			tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
1647 			l_ptr->stats.bearer_congs++;
1648 			l_ptr->retransm_queue_head = msg_seqno(buf_msg(buf));
1649 			l_ptr->retransm_queue_size = retransmits;
1650 			return;
1651 		}
1652 	}
1653 	l_ptr->retransm_queue_head = l_ptr->retransm_queue_size = 0;
1654 }
1655 
1656 /*
1657  * link_recv_non_seq: Receive packets which are outside
1658  *                    the link sequence flow
1659  */
1660 
1661 static void link_recv_non_seq(struct sk_buff *buf)
1662 {
1663 	struct tipc_msg *msg = buf_msg(buf);
1664 
1665 	if (msg_user(msg) ==  LINK_CONFIG)
1666 		tipc_disc_recv_msg(buf);
1667 	else
1668 		tipc_bclink_recv_pkt(buf);
1669 }
1670 
1671 /**
1672  * link_insert_deferred_queue - insert deferred messages back into receive chain
1673  */
1674 
1675 static struct sk_buff *link_insert_deferred_queue(struct link *l_ptr,
1676 						  struct sk_buff *buf)
1677 {
1678 	u32 seq_no;
1679 
1680 	if (l_ptr->oldest_deferred_in == NULL)
1681 		return buf;
1682 
1683 	seq_no = msg_seqno(buf_msg(l_ptr->oldest_deferred_in));
1684 	if (seq_no == mod(l_ptr->next_in_no)) {
1685 		l_ptr->newest_deferred_in->next = buf;
1686 		buf = l_ptr->oldest_deferred_in;
1687 		l_ptr->oldest_deferred_in = NULL;
1688 		l_ptr->deferred_inqueue_sz = 0;
1689 	}
1690 	return buf;
1691 }
1692 
1693 void tipc_recv_msg(struct sk_buff *head, struct tipc_bearer *tb_ptr)
1694 {
1695 	read_lock_bh(&tipc_net_lock);
1696 	while (head) {
1697 		struct bearer *b_ptr;
1698 		struct node *n_ptr;
1699 		struct link *l_ptr;
1700 		struct sk_buff *crs;
1701 		struct sk_buff *buf = head;
1702 		struct tipc_msg *msg = buf_msg(buf);
1703 		u32 seq_no = msg_seqno(msg);
1704 		u32 ackd = msg_ack(msg);
1705 		u32 released = 0;
1706 		int type;
1707 
1708 		b_ptr = (struct bearer *)tb_ptr;
1709 		TIPC_SKB_CB(buf)->handle = b_ptr;
1710 
1711 		head = head->next;
1712 		if (unlikely(msg_version(msg) != TIPC_VERSION))
1713 			goto cont;
1714 #if 0
1715 		if (msg_user(msg) != LINK_PROTOCOL)
1716 #endif
1717 			msg_dbg(msg,"<REC<");
1718 
1719 		if (unlikely(msg_non_seq(msg))) {
1720 			link_recv_non_seq(buf);
1721 			continue;
1722 		}
1723 		n_ptr = tipc_node_find(msg_prevnode(msg));
1724 		if (unlikely(!n_ptr))
1725 			goto cont;
1726 
1727 		tipc_node_lock(n_ptr);
1728 		l_ptr = n_ptr->links[b_ptr->identity];
1729 		if (unlikely(!l_ptr)) {
1730 			tipc_node_unlock(n_ptr);
1731 			goto cont;
1732 		}
1733 		/*
1734 		 * Release acked messages
1735 		 */
1736 		if (less(n_ptr->bclink.acked, msg_bcast_ack(msg))) {
1737 			if (tipc_node_is_up(n_ptr) && n_ptr->bclink.supported)
1738 				tipc_bclink_acknowledge(n_ptr, msg_bcast_ack(msg));
1739 		}
1740 
1741 		crs = l_ptr->first_out;
1742 		while ((crs != l_ptr->next_out) &&
1743 		       less_eq(msg_seqno(buf_msg(crs)), ackd)) {
1744 			struct sk_buff *next = crs->next;
1745 
1746 			buf_discard(crs);
1747 			crs = next;
1748 			released++;
1749 		}
1750 		if (released) {
1751 			l_ptr->first_out = crs;
1752 			l_ptr->out_queue_size -= released;
1753 		}
1754 		if (unlikely(l_ptr->next_out))
1755 			tipc_link_push_queue(l_ptr);
1756 		if (unlikely(!list_empty(&l_ptr->waiting_ports)))
1757 			tipc_link_wakeup_ports(l_ptr, 0);
1758 		if (unlikely(++l_ptr->unacked_window >= TIPC_MIN_LINK_WIN)) {
1759 			l_ptr->stats.sent_acks++;
1760 			tipc_link_send_proto_msg(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
1761 		}
1762 
1763 protocol_check:
1764 		if (likely(link_working_working(l_ptr))) {
1765 			if (likely(seq_no == mod(l_ptr->next_in_no))) {
1766 				l_ptr->next_in_no++;
1767 				if (unlikely(l_ptr->oldest_deferred_in))
1768 					head = link_insert_deferred_queue(l_ptr,
1769 									  head);
1770 				if (likely(msg_is_dest(msg, tipc_own_addr))) {
1771 deliver:
1772 					if (likely(msg_isdata(msg))) {
1773 						tipc_node_unlock(n_ptr);
1774 						tipc_port_recv_msg(buf);
1775 						continue;
1776 					}
1777 					switch (msg_user(msg)) {
1778 					case MSG_BUNDLER:
1779 						l_ptr->stats.recv_bundles++;
1780 						l_ptr->stats.recv_bundled +=
1781 							msg_msgcnt(msg);
1782 						tipc_node_unlock(n_ptr);
1783 						tipc_link_recv_bundle(buf);
1784 						continue;
1785 					case ROUTE_DISTRIBUTOR:
1786 						tipc_node_unlock(n_ptr);
1787 						tipc_cltr_recv_routing_table(buf);
1788 						continue;
1789 					case NAME_DISTRIBUTOR:
1790 						tipc_node_unlock(n_ptr);
1791 						tipc_named_recv(buf);
1792 						continue;
1793 					case CONN_MANAGER:
1794 						tipc_node_unlock(n_ptr);
1795 						tipc_port_recv_proto_msg(buf);
1796 						continue;
1797 					case MSG_FRAGMENTER:
1798 						l_ptr->stats.recv_fragments++;
1799 						if (tipc_link_recv_fragment(&l_ptr->defragm_buf,
1800 									    &buf, &msg)) {
1801 							l_ptr->stats.recv_fragmented++;
1802 							goto deliver;
1803 						}
1804 						break;
1805 					case CHANGEOVER_PROTOCOL:
1806 						type = msg_type(msg);
1807 						if (link_recv_changeover_msg(&l_ptr, &buf)) {
1808 							msg = buf_msg(buf);
1809 							seq_no = msg_seqno(msg);
1810 							TIPC_SKB_CB(buf)->handle
1811 								= b_ptr;
1812 							if (type == ORIGINAL_MSG)
1813 								goto deliver;
1814 							goto protocol_check;
1815 						}
1816 						break;
1817 					}
1818 				}
1819 				tipc_node_unlock(n_ptr);
1820 				tipc_net_route_msg(buf);
1821 				continue;
1822 			}
1823 			link_handle_out_of_seq_msg(l_ptr, buf);
1824 			head = link_insert_deferred_queue(l_ptr, head);
1825 			tipc_node_unlock(n_ptr);
1826 			continue;
1827 		}
1828 
1829 		if (msg_user(msg) == LINK_PROTOCOL) {
1830 			link_recv_proto_msg(l_ptr, buf);
1831 			head = link_insert_deferred_queue(l_ptr, head);
1832 			tipc_node_unlock(n_ptr);
1833 			continue;
1834 		}
1835 		msg_dbg(msg,"NSEQ<REC<");
1836 		link_state_event(l_ptr, TRAFFIC_MSG_EVT);
1837 
1838 		if (link_working_working(l_ptr)) {
1839 			/* Re-insert in front of queue */
1840 			msg_dbg(msg,"RECV-REINS:");
1841 			buf->next = head;
1842 			head = buf;
1843 			tipc_node_unlock(n_ptr);
1844 			continue;
1845 		}
1846 		tipc_node_unlock(n_ptr);
1847 cont:
1848 		buf_discard(buf);
1849 	}
1850 	read_unlock_bh(&tipc_net_lock);
1851 }
1852 
1853 /*
1854  * link_defer_buf(): Sort a received out-of-sequence packet
1855  *                   into the deferred reception queue.
1856  * Returns the increase of the queue length,i.e. 0 or 1
1857  */
1858 
1859 u32 tipc_link_defer_pkt(struct sk_buff **head,
1860 			struct sk_buff **tail,
1861 			struct sk_buff *buf)
1862 {
1863 	struct sk_buff *prev = 0;
1864 	struct sk_buff *crs = *head;
1865 	u32 seq_no = msg_seqno(buf_msg(buf));
1866 
1867 	buf->next = NULL;
1868 
1869 	/* Empty queue ? */
1870 	if (*head == NULL) {
1871 		*head = *tail = buf;
1872 		return 1;
1873 	}
1874 
1875 	/* Last ? */
1876 	if (less(msg_seqno(buf_msg(*tail)), seq_no)) {
1877 		(*tail)->next = buf;
1878 		*tail = buf;
1879 		return 1;
1880 	}
1881 
1882 	/* Scan through queue and sort it in */
1883 	do {
1884 		struct tipc_msg *msg = buf_msg(crs);
1885 
1886 		if (less(seq_no, msg_seqno(msg))) {
1887 			buf->next = crs;
1888 			if (prev)
1889 				prev->next = buf;
1890 			else
1891 				*head = buf;
1892 			return 1;
1893 		}
1894 		if (seq_no == msg_seqno(msg)) {
1895 			break;
1896 		}
1897 		prev = crs;
1898 		crs = crs->next;
1899 	}
1900 	while (crs);
1901 
1902 	/* Message is a duplicate of an existing message */
1903 
1904 	buf_discard(buf);
1905 	return 0;
1906 }
1907 
1908 /**
1909  * link_handle_out_of_seq_msg - handle arrival of out-of-sequence packet
1910  */
1911 
1912 static void link_handle_out_of_seq_msg(struct link *l_ptr,
1913 				       struct sk_buff *buf)
1914 {
1915 	u32 seq_no = msg_seqno(buf_msg(buf));
1916 
1917 	if (likely(msg_user(buf_msg(buf)) == LINK_PROTOCOL)) {
1918 		link_recv_proto_msg(l_ptr, buf);
1919 		return;
1920 	}
1921 
1922 	dbg("rx OOS msg: seq_no %u, expecting %u (%u)\n",
1923 	    seq_no, mod(l_ptr->next_in_no), l_ptr->next_in_no);
1924 
1925 	/* Record OOS packet arrival (force mismatch on next timeout) */
1926 
1927 	l_ptr->checkpoint--;
1928 
1929 	/*
1930 	 * Discard packet if a duplicate; otherwise add it to deferred queue
1931 	 * and notify peer of gap as per protocol specification
1932 	 */
1933 
1934 	if (less(seq_no, mod(l_ptr->next_in_no))) {
1935 		l_ptr->stats.duplicates++;
1936 		buf_discard(buf);
1937 		return;
1938 	}
1939 
1940 	if (tipc_link_defer_pkt(&l_ptr->oldest_deferred_in,
1941 				&l_ptr->newest_deferred_in, buf)) {
1942 		l_ptr->deferred_inqueue_sz++;
1943 		l_ptr->stats.deferred_recv++;
1944 		if ((l_ptr->deferred_inqueue_sz % 16) == 1)
1945 			tipc_link_send_proto_msg(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
1946 	} else
1947 		l_ptr->stats.duplicates++;
1948 }
1949 
1950 /*
1951  * Send protocol message to the other endpoint.
1952  */
1953 void tipc_link_send_proto_msg(struct link *l_ptr, u32 msg_typ, int probe_msg,
1954 			      u32 gap, u32 tolerance, u32 priority, u32 ack_mtu)
1955 {
1956 	struct sk_buff *buf = 0;
1957 	struct tipc_msg *msg = l_ptr->pmsg;
1958         u32 msg_size = sizeof(l_ptr->proto_msg);
1959 
1960 	if (link_blocked(l_ptr))
1961 		return;
1962 	msg_set_type(msg, msg_typ);
1963 	msg_set_net_plane(msg, l_ptr->b_ptr->net_plane);
1964 	msg_set_bcast_ack(msg, mod(l_ptr->owner->bclink.last_in));
1965 	msg_set_last_bcast(msg, tipc_bclink_get_last_sent());
1966 
1967 	if (msg_typ == STATE_MSG) {
1968 		u32 next_sent = mod(l_ptr->next_out_no);
1969 
1970 		if (!tipc_link_is_up(l_ptr))
1971 			return;
1972 		if (l_ptr->next_out)
1973 			next_sent = msg_seqno(buf_msg(l_ptr->next_out));
1974 		msg_set_next_sent(msg, next_sent);
1975 		if (l_ptr->oldest_deferred_in) {
1976 			u32 rec = msg_seqno(buf_msg(l_ptr->oldest_deferred_in));
1977 			gap = mod(rec - mod(l_ptr->next_in_no));
1978 		}
1979 		msg_set_seq_gap(msg, gap);
1980 		if (gap)
1981 			l_ptr->stats.sent_nacks++;
1982 		msg_set_link_tolerance(msg, tolerance);
1983 		msg_set_linkprio(msg, priority);
1984 		msg_set_max_pkt(msg, ack_mtu);
1985 		msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1986 		msg_set_probe(msg, probe_msg != 0);
1987 		if (probe_msg) {
1988 			u32 mtu = l_ptr->max_pkt;
1989 
1990                         if ((mtu < l_ptr->max_pkt_target) &&
1991 			    link_working_working(l_ptr) &&
1992 			    l_ptr->fsm_msg_cnt) {
1993 				msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
1994                                 if (l_ptr->max_pkt_probes == 10) {
1995                                         l_ptr->max_pkt_target = (msg_size - 4);
1996                                         l_ptr->max_pkt_probes = 0;
1997 					msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
1998                                 }
1999 				l_ptr->max_pkt_probes++;
2000                         }
2001 
2002 			l_ptr->stats.sent_probes++;
2003                 }
2004 		l_ptr->stats.sent_states++;
2005 	} else {		/* RESET_MSG or ACTIVATE_MSG */
2006 		msg_set_ack(msg, mod(l_ptr->reset_checkpoint - 1));
2007 		msg_set_seq_gap(msg, 0);
2008 		msg_set_next_sent(msg, 1);
2009 		msg_set_link_tolerance(msg, l_ptr->tolerance);
2010 		msg_set_linkprio(msg, l_ptr->priority);
2011 		msg_set_max_pkt(msg, l_ptr->max_pkt_target);
2012 	}
2013 
2014 	if (tipc_node_has_redundant_links(l_ptr->owner)) {
2015 		msg_set_redundant_link(msg);
2016 	} else {
2017 		msg_clear_redundant_link(msg);
2018 	}
2019 	msg_set_linkprio(msg, l_ptr->priority);
2020 
2021 	/* Ensure sequence number will not fit : */
2022 
2023 	msg_set_seqno(msg, mod(l_ptr->next_out_no + (0xffff/2)));
2024 
2025 	/* Congestion? */
2026 
2027 	if (tipc_bearer_congested(l_ptr->b_ptr, l_ptr)) {
2028 		if (!l_ptr->proto_msg_queue) {
2029 			l_ptr->proto_msg_queue =
2030 				buf_acquire(sizeof(l_ptr->proto_msg));
2031 		}
2032 		buf = l_ptr->proto_msg_queue;
2033 		if (!buf)
2034 			return;
2035 		memcpy(buf->data, (unchar *)msg, sizeof(l_ptr->proto_msg));
2036 		return;
2037 	}
2038 	msg_set_timestamp(msg, jiffies_to_msecs(jiffies));
2039 
2040 	/* Message can be sent */
2041 
2042 	msg_dbg(msg, ">>");
2043 
2044 	buf = buf_acquire(msg_size);
2045 	if (!buf)
2046 		return;
2047 
2048 	memcpy(buf->data, (unchar *)msg, sizeof(l_ptr->proto_msg));
2049         msg_set_size(buf_msg(buf), msg_size);
2050 
2051 	if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
2052 		l_ptr->unacked_window = 0;
2053 		buf_discard(buf);
2054 		return;
2055 	}
2056 
2057 	/* New congestion */
2058 	tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
2059 	l_ptr->proto_msg_queue = buf;
2060 	l_ptr->stats.bearer_congs++;
2061 }
2062 
2063 /*
2064  * Receive protocol message :
2065  * Note that network plane id propagates through the network, and may
2066  * change at any time. The node with lowest address rules
2067  */
2068 
2069 static void link_recv_proto_msg(struct link *l_ptr, struct sk_buff *buf)
2070 {
2071 	u32 rec_gap = 0;
2072 	u32 max_pkt_info;
2073         u32 max_pkt_ack;
2074 	u32 msg_tol;
2075 	struct tipc_msg *msg = buf_msg(buf);
2076 
2077 	dbg("AT(%u):", jiffies_to_msecs(jiffies));
2078 	msg_dbg(msg, "<<");
2079 	if (link_blocked(l_ptr))
2080 		goto exit;
2081 
2082 	/* record unnumbered packet arrival (force mismatch on next timeout) */
2083 
2084 	l_ptr->checkpoint--;
2085 
2086 	if (l_ptr->b_ptr->net_plane != msg_net_plane(msg))
2087 		if (tipc_own_addr > msg_prevnode(msg))
2088 			l_ptr->b_ptr->net_plane = msg_net_plane(msg);
2089 
2090 	l_ptr->owner->permit_changeover = msg_redundant_link(msg);
2091 
2092 	switch (msg_type(msg)) {
2093 
2094 	case RESET_MSG:
2095 		if (!link_working_unknown(l_ptr) && l_ptr->peer_session) {
2096 			if (msg_session(msg) == l_ptr->peer_session) {
2097 				dbg("Duplicate RESET: %u<->%u\n",
2098 				    msg_session(msg), l_ptr->peer_session);
2099 				break; /* duplicate: ignore */
2100 			}
2101 		}
2102 		/* fall thru' */
2103 	case ACTIVATE_MSG:
2104 		/* Update link settings according other endpoint's values */
2105 
2106 		strcpy((strrchr(l_ptr->name, ':') + 1), (char *)msg_data(msg));
2107 
2108 		if ((msg_tol = msg_link_tolerance(msg)) &&
2109 		    (msg_tol > l_ptr->tolerance))
2110 			link_set_supervision_props(l_ptr, msg_tol);
2111 
2112 		if (msg_linkprio(msg) > l_ptr->priority)
2113 			l_ptr->priority = msg_linkprio(msg);
2114 
2115 		max_pkt_info = msg_max_pkt(msg);
2116                 if (max_pkt_info) {
2117 			if (max_pkt_info < l_ptr->max_pkt_target)
2118 				l_ptr->max_pkt_target = max_pkt_info;
2119 			if (l_ptr->max_pkt > l_ptr->max_pkt_target)
2120 				l_ptr->max_pkt = l_ptr->max_pkt_target;
2121 		} else {
2122                         l_ptr->max_pkt = l_ptr->max_pkt_target;
2123 		}
2124 		l_ptr->owner->bclink.supported = (max_pkt_info != 0);
2125 
2126 		link_state_event(l_ptr, msg_type(msg));
2127 
2128 		l_ptr->peer_session = msg_session(msg);
2129 		l_ptr->peer_bearer_id = msg_bearer_id(msg);
2130 
2131 		/* Synchronize broadcast sequence numbers */
2132 		if (!tipc_node_has_redundant_links(l_ptr->owner)) {
2133 			l_ptr->owner->bclink.last_in = mod(msg_last_bcast(msg));
2134 		}
2135 		break;
2136 	case STATE_MSG:
2137 
2138 		if ((msg_tol = msg_link_tolerance(msg)))
2139 			link_set_supervision_props(l_ptr, msg_tol);
2140 
2141 		if (msg_linkprio(msg) &&
2142 		    (msg_linkprio(msg) != l_ptr->priority)) {
2143 			warn("Changing prio <%s>: %u->%u\n",
2144 			     l_ptr->name, l_ptr->priority, msg_linkprio(msg));
2145 			l_ptr->priority = msg_linkprio(msg);
2146 			tipc_link_reset(l_ptr); /* Enforce change to take effect */
2147 			break;
2148 		}
2149 		link_state_event(l_ptr, TRAFFIC_MSG_EVT);
2150 		l_ptr->stats.recv_states++;
2151 		if (link_reset_unknown(l_ptr))
2152 			break;
2153 
2154 		if (less_eq(mod(l_ptr->next_in_no), msg_next_sent(msg))) {
2155 			rec_gap = mod(msg_next_sent(msg) -
2156 				      mod(l_ptr->next_in_no));
2157 		}
2158 
2159 		max_pkt_ack = msg_max_pkt(msg);
2160                 if (max_pkt_ack > l_ptr->max_pkt) {
2161                         dbg("Link <%s> updated MTU %u -> %u\n",
2162                             l_ptr->name, l_ptr->max_pkt, max_pkt_ack);
2163                         l_ptr->max_pkt = max_pkt_ack;
2164                         l_ptr->max_pkt_probes = 0;
2165                 }
2166 
2167 		max_pkt_ack = 0;
2168                 if (msg_probe(msg)) {
2169 			l_ptr->stats.recv_probes++;
2170                         if (msg_size(msg) > sizeof(l_ptr->proto_msg)) {
2171                                 max_pkt_ack = msg_size(msg);
2172                         }
2173                 }
2174 
2175 		/* Protocol message before retransmits, reduce loss risk */
2176 
2177 		tipc_bclink_check_gap(l_ptr->owner, msg_last_bcast(msg));
2178 
2179 		if (rec_gap || (msg_probe(msg))) {
2180 			tipc_link_send_proto_msg(l_ptr, STATE_MSG,
2181 						 0, rec_gap, 0, 0, max_pkt_ack);
2182 		}
2183 		if (msg_seq_gap(msg)) {
2184 			msg_dbg(msg, "With Gap:");
2185 			l_ptr->stats.recv_nacks++;
2186 			tipc_link_retransmit(l_ptr, l_ptr->first_out,
2187 					     msg_seq_gap(msg));
2188 		}
2189 		break;
2190 	default:
2191 		msg_dbg(buf_msg(buf), "<DISCARDING UNKNOWN<");
2192 	}
2193 exit:
2194 	buf_discard(buf);
2195 }
2196 
2197 
2198 /*
2199  * tipc_link_tunnel(): Send one message via a link belonging to
2200  * another bearer. Owner node is locked.
2201  */
2202 void tipc_link_tunnel(struct link *l_ptr,
2203 		      struct tipc_msg *tunnel_hdr,
2204 		      struct tipc_msg  *msg,
2205 		      u32 selector)
2206 {
2207 	struct link *tunnel;
2208 	struct sk_buff *buf;
2209 	u32 length = msg_size(msg);
2210 
2211 	tunnel = l_ptr->owner->active_links[selector & 1];
2212 	if (!tipc_link_is_up(tunnel))
2213 		return;
2214 	msg_set_size(tunnel_hdr, length + INT_H_SIZE);
2215 	buf = buf_acquire(length + INT_H_SIZE);
2216 	if (!buf)
2217 		return;
2218 	memcpy(buf->data, (unchar *)tunnel_hdr, INT_H_SIZE);
2219 	memcpy(buf->data + INT_H_SIZE, (unchar *)msg, length);
2220 	dbg("%c->%c:", l_ptr->b_ptr->net_plane, tunnel->b_ptr->net_plane);
2221 	msg_dbg(buf_msg(buf), ">SEND>");
2222 	assert(tunnel);
2223 	tipc_link_send_buf(tunnel, buf);
2224 }
2225 
2226 
2227 
2228 /*
2229  * changeover(): Send whole message queue via the remaining link
2230  *               Owner node is locked.
2231  */
2232 
2233 void tipc_link_changeover(struct link *l_ptr)
2234 {
2235 	u32 msgcount = l_ptr->out_queue_size;
2236 	struct sk_buff *crs = l_ptr->first_out;
2237 	struct link *tunnel = l_ptr->owner->active_links[0];
2238 	int split_bundles = tipc_node_has_redundant_links(l_ptr->owner);
2239 	struct tipc_msg tunnel_hdr;
2240 
2241 	if (!tunnel)
2242 		return;
2243 
2244 	if (!l_ptr->owner->permit_changeover)
2245 		return;
2246 
2247 	msg_init(&tunnel_hdr, CHANGEOVER_PROTOCOL,
2248 		 ORIGINAL_MSG, TIPC_OK, INT_H_SIZE, l_ptr->addr);
2249 	msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
2250 	msg_set_msgcnt(&tunnel_hdr, msgcount);
2251 	if (!l_ptr->first_out) {
2252 		struct sk_buff *buf;
2253 
2254 		assert(!msgcount);
2255 		buf = buf_acquire(INT_H_SIZE);
2256 		if (buf) {
2257 			memcpy(buf->data, (unchar *)&tunnel_hdr, INT_H_SIZE);
2258 			msg_set_size(&tunnel_hdr, INT_H_SIZE);
2259 			dbg("%c->%c:", l_ptr->b_ptr->net_plane,
2260 			    tunnel->b_ptr->net_plane);
2261 			msg_dbg(&tunnel_hdr, "EMPTY>SEND>");
2262 			tipc_link_send_buf(tunnel, buf);
2263 		} else {
2264 			warn("Memory squeeze; link changeover failed\n");
2265 		}
2266 		return;
2267 	}
2268 	while (crs) {
2269 		struct tipc_msg *msg = buf_msg(crs);
2270 
2271 		if ((msg_user(msg) == MSG_BUNDLER) && split_bundles) {
2272 			u32 msgcount = msg_msgcnt(msg);
2273 			struct tipc_msg *m = msg_get_wrapped(msg);
2274 			unchar* pos = (unchar*)m;
2275 
2276 			while (msgcount--) {
2277 				msg_set_seqno(m,msg_seqno(msg));
2278 				tipc_link_tunnel(l_ptr, &tunnel_hdr, m,
2279 						 msg_link_selector(m));
2280 				pos += align(msg_size(m));
2281 				m = (struct tipc_msg *)pos;
2282 			}
2283 		} else {
2284 			tipc_link_tunnel(l_ptr, &tunnel_hdr, msg,
2285 					 msg_link_selector(msg));
2286 		}
2287 		crs = crs->next;
2288 	}
2289 }
2290 
2291 void tipc_link_send_duplicate(struct link *l_ptr, struct link *tunnel)
2292 {
2293 	struct sk_buff *iter;
2294 	struct tipc_msg tunnel_hdr;
2295 
2296 	msg_init(&tunnel_hdr, CHANGEOVER_PROTOCOL,
2297 		 DUPLICATE_MSG, TIPC_OK, INT_H_SIZE, l_ptr->addr);
2298 	msg_set_msgcnt(&tunnel_hdr, l_ptr->out_queue_size);
2299 	msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
2300 	iter = l_ptr->first_out;
2301 	while (iter) {
2302 		struct sk_buff *outbuf;
2303 		struct tipc_msg *msg = buf_msg(iter);
2304 		u32 length = msg_size(msg);
2305 
2306 		if (msg_user(msg) == MSG_BUNDLER)
2307 			msg_set_type(msg, CLOSED_MSG);
2308 		msg_set_ack(msg, mod(l_ptr->next_in_no - 1));	/* Update */
2309 		msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
2310 		msg_set_size(&tunnel_hdr, length + INT_H_SIZE);
2311 		outbuf = buf_acquire(length + INT_H_SIZE);
2312 		if (outbuf == NULL) {
2313 			warn("Memory squeeze; buffer duplication failed\n");
2314 			return;
2315 		}
2316 		memcpy(outbuf->data, (unchar *)&tunnel_hdr, INT_H_SIZE);
2317 		memcpy(outbuf->data + INT_H_SIZE, iter->data, length);
2318 		dbg("%c->%c:", l_ptr->b_ptr->net_plane,
2319 		    tunnel->b_ptr->net_plane);
2320 		msg_dbg(buf_msg(outbuf), ">SEND>");
2321 		tipc_link_send_buf(tunnel, outbuf);
2322 		if (!tipc_link_is_up(l_ptr))
2323 			return;
2324 		iter = iter->next;
2325 	}
2326 }
2327 
2328 
2329 
2330 /**
2331  * buf_extract - extracts embedded TIPC message from another message
2332  * @skb: encapsulating message buffer
2333  * @from_pos: offset to extract from
2334  *
2335  * Returns a new message buffer containing an embedded message.  The
2336  * encapsulating message itself is left unchanged.
2337  */
2338 
2339 static struct sk_buff *buf_extract(struct sk_buff *skb, u32 from_pos)
2340 {
2341 	struct tipc_msg *msg = (struct tipc_msg *)(skb->data + from_pos);
2342 	u32 size = msg_size(msg);
2343 	struct sk_buff *eb;
2344 
2345 	eb = buf_acquire(size);
2346 	if (eb)
2347 		memcpy(eb->data, (unchar *)msg, size);
2348 	return eb;
2349 }
2350 
2351 /*
2352  *  link_recv_changeover_msg(): Receive tunneled packet sent
2353  *  via other link. Node is locked. Return extracted buffer.
2354  */
2355 
2356 static int link_recv_changeover_msg(struct link **l_ptr,
2357 				    struct sk_buff **buf)
2358 {
2359 	struct sk_buff *tunnel_buf = *buf;
2360 	struct link *dest_link;
2361 	struct tipc_msg *msg;
2362 	struct tipc_msg *tunnel_msg = buf_msg(tunnel_buf);
2363 	u32 msg_typ = msg_type(tunnel_msg);
2364 	u32 msg_count = msg_msgcnt(tunnel_msg);
2365 
2366 	dest_link = (*l_ptr)->owner->links[msg_bearer_id(tunnel_msg)];
2367 	assert(dest_link != *l_ptr);
2368 	if (!dest_link) {
2369 		msg_dbg(tunnel_msg, "NOLINK/<REC<");
2370 		goto exit;
2371 	}
2372 	dbg("%c<-%c:", dest_link->b_ptr->net_plane,
2373 	    (*l_ptr)->b_ptr->net_plane);
2374 	*l_ptr = dest_link;
2375 	msg = msg_get_wrapped(tunnel_msg);
2376 
2377 	if (msg_typ == DUPLICATE_MSG) {
2378 		if (less(msg_seqno(msg), mod(dest_link->next_in_no))) {
2379 			msg_dbg(tunnel_msg, "DROP/<REC<");
2380 			goto exit;
2381 		}
2382 		*buf = buf_extract(tunnel_buf,INT_H_SIZE);
2383 		if (*buf == NULL) {
2384 			warn("Memory squeeze; failed to extract msg\n");
2385 			goto exit;
2386 		}
2387 		msg_dbg(tunnel_msg, "TNL<REC<");
2388 		buf_discard(tunnel_buf);
2389 		return 1;
2390 	}
2391 
2392 	/* First original message ?: */
2393 
2394 	if (tipc_link_is_up(dest_link)) {
2395 		msg_dbg(tunnel_msg, "UP/FIRST/<REC<");
2396 		tipc_link_reset(dest_link);
2397 		dest_link->exp_msg_count = msg_count;
2398 		if (!msg_count)
2399 			goto exit;
2400 	} else if (dest_link->exp_msg_count == START_CHANGEOVER) {
2401 		msg_dbg(tunnel_msg, "BLK/FIRST/<REC<");
2402 		dest_link->exp_msg_count = msg_count;
2403 		if (!msg_count)
2404 			goto exit;
2405 	}
2406 
2407 	/* Receive original message */
2408 
2409 	if (dest_link->exp_msg_count == 0) {
2410 		msg_dbg(tunnel_msg, "OVERDUE/DROP/<REC<");
2411 		dbg_print_link(dest_link, "LINK:");
2412 		goto exit;
2413 	}
2414 	dest_link->exp_msg_count--;
2415 	if (less(msg_seqno(msg), dest_link->reset_checkpoint)) {
2416 		msg_dbg(tunnel_msg, "DROP/DUPL/<REC<");
2417 		goto exit;
2418 	} else {
2419 		*buf = buf_extract(tunnel_buf, INT_H_SIZE);
2420 		if (*buf != NULL) {
2421 			msg_dbg(tunnel_msg, "TNL<REC<");
2422 			buf_discard(tunnel_buf);
2423 			return 1;
2424 		} else {
2425 			warn("Memory squeeze; dropped incoming msg\n");
2426 		}
2427 	}
2428 exit:
2429 	*buf = 0;
2430 	buf_discard(tunnel_buf);
2431 	return 0;
2432 }
2433 
2434 /*
2435  *  Bundler functionality:
2436  */
2437 void tipc_link_recv_bundle(struct sk_buff *buf)
2438 {
2439 	u32 msgcount = msg_msgcnt(buf_msg(buf));
2440 	u32 pos = INT_H_SIZE;
2441 	struct sk_buff *obuf;
2442 
2443 	msg_dbg(buf_msg(buf), "<BNDL<: ");
2444 	while (msgcount--) {
2445 		obuf = buf_extract(buf, pos);
2446 		if (obuf == NULL) {
2447 			char addr_string[16];
2448 
2449 			warn("Buffer allocation failure;\n");
2450 			warn("  incoming message(s) from %s lost\n",
2451 			     addr_string_fill(addr_string,
2452 					      msg_orignode(buf_msg(buf))));
2453 			return;
2454 		};
2455 		pos += align(msg_size(buf_msg(obuf)));
2456 		msg_dbg(buf_msg(obuf), "     /");
2457 		tipc_net_route_msg(obuf);
2458 	}
2459 	buf_discard(buf);
2460 }
2461 
2462 /*
2463  *  Fragmentation/defragmentation:
2464  */
2465 
2466 
2467 /*
2468  * tipc_link_send_long_buf: Entry for buffers needing fragmentation.
2469  * The buffer is complete, inclusive total message length.
2470  * Returns user data length.
2471  */
2472 int tipc_link_send_long_buf(struct link *l_ptr, struct sk_buff *buf)
2473 {
2474 	struct tipc_msg *inmsg = buf_msg(buf);
2475 	struct tipc_msg fragm_hdr;
2476 	u32 insize = msg_size(inmsg);
2477 	u32 dsz = msg_data_sz(inmsg);
2478 	unchar *crs = buf->data;
2479 	u32 rest = insize;
2480 	u32 pack_sz = link_max_pkt(l_ptr);
2481 	u32 fragm_sz = pack_sz - INT_H_SIZE;
2482 	u32 fragm_no = 1;
2483 	u32 destaddr = msg_destnode(inmsg);
2484 
2485 	if (msg_short(inmsg))
2486 		destaddr = l_ptr->addr;
2487 
2488 	if (msg_routed(inmsg))
2489 		msg_set_prevnode(inmsg, tipc_own_addr);
2490 
2491 	/* Prepare reusable fragment header: */
2492 
2493 	msg_init(&fragm_hdr, MSG_FRAGMENTER, FIRST_FRAGMENT,
2494 		 TIPC_OK, INT_H_SIZE, destaddr);
2495 	msg_set_link_selector(&fragm_hdr, msg_link_selector(inmsg));
2496 	msg_set_long_msgno(&fragm_hdr, mod(l_ptr->long_msg_seq_no++));
2497 	msg_set_fragm_no(&fragm_hdr, fragm_no);
2498 	l_ptr->stats.sent_fragmented++;
2499 
2500 	/* Chop up message: */
2501 
2502 	while (rest > 0) {
2503 		struct sk_buff *fragm;
2504 
2505 		if (rest <= fragm_sz) {
2506 			fragm_sz = rest;
2507 			msg_set_type(&fragm_hdr, LAST_FRAGMENT);
2508 		}
2509 		fragm = buf_acquire(fragm_sz + INT_H_SIZE);
2510 		if (fragm == NULL) {
2511 			warn("Memory squeeze; failed to fragment msg\n");
2512 			dsz = -ENOMEM;
2513 			goto exit;
2514 		}
2515 		msg_set_size(&fragm_hdr, fragm_sz + INT_H_SIZE);
2516 		memcpy(fragm->data, (unchar *)&fragm_hdr, INT_H_SIZE);
2517 		memcpy(fragm->data + INT_H_SIZE, crs, fragm_sz);
2518 
2519 		/*  Send queued messages first, if any: */
2520 
2521 		l_ptr->stats.sent_fragments++;
2522 		tipc_link_send_buf(l_ptr, fragm);
2523 		if (!tipc_link_is_up(l_ptr))
2524 			return dsz;
2525 		msg_set_fragm_no(&fragm_hdr, ++fragm_no);
2526 		rest -= fragm_sz;
2527 		crs += fragm_sz;
2528 		msg_set_type(&fragm_hdr, FRAGMENT);
2529 	}
2530 exit:
2531 	buf_discard(buf);
2532 	return dsz;
2533 }
2534 
2535 /*
2536  * A pending message being re-assembled must store certain values
2537  * to handle subsequent fragments correctly. The following functions
2538  * help storing these values in unused, available fields in the
2539  * pending message. This makes dynamic memory allocation unecessary.
2540  */
2541 
2542 static inline u32 get_long_msg_seqno(struct sk_buff *buf)
2543 {
2544 	return msg_seqno(buf_msg(buf));
2545 }
2546 
2547 static inline void set_long_msg_seqno(struct sk_buff *buf, u32 seqno)
2548 {
2549 	msg_set_seqno(buf_msg(buf), seqno);
2550 }
2551 
2552 static inline u32 get_fragm_size(struct sk_buff *buf)
2553 {
2554 	return msg_ack(buf_msg(buf));
2555 }
2556 
2557 static inline void set_fragm_size(struct sk_buff *buf, u32 sz)
2558 {
2559 	msg_set_ack(buf_msg(buf), sz);
2560 }
2561 
2562 static inline u32 get_expected_frags(struct sk_buff *buf)
2563 {
2564 	return msg_bcast_ack(buf_msg(buf));
2565 }
2566 
2567 static inline void set_expected_frags(struct sk_buff *buf, u32 exp)
2568 {
2569 	msg_set_bcast_ack(buf_msg(buf), exp);
2570 }
2571 
2572 static inline u32 get_timer_cnt(struct sk_buff *buf)
2573 {
2574 	return msg_reroute_cnt(buf_msg(buf));
2575 }
2576 
2577 static inline void incr_timer_cnt(struct sk_buff *buf)
2578 {
2579 	msg_incr_reroute_cnt(buf_msg(buf));
2580 }
2581 
2582 /*
2583  * tipc_link_recv_fragment(): Called with node lock on. Returns
2584  * the reassembled buffer if message is complete.
2585  */
2586 int tipc_link_recv_fragment(struct sk_buff **pending, struct sk_buff **fb,
2587 			    struct tipc_msg **m)
2588 {
2589 	struct sk_buff *prev = 0;
2590 	struct sk_buff *fbuf = *fb;
2591 	struct tipc_msg *fragm = buf_msg(fbuf);
2592 	struct sk_buff *pbuf = *pending;
2593 	u32 long_msg_seq_no = msg_long_msgno(fragm);
2594 
2595 	*fb = 0;
2596 	msg_dbg(fragm,"FRG<REC<");
2597 
2598 	/* Is there an incomplete message waiting for this fragment? */
2599 
2600 	while (pbuf && ((msg_seqno(buf_msg(pbuf)) != long_msg_seq_no)
2601 			|| (msg_orignode(fragm) != msg_orignode(buf_msg(pbuf))))) {
2602 		prev = pbuf;
2603 		pbuf = pbuf->next;
2604 	}
2605 
2606 	if (!pbuf && (msg_type(fragm) == FIRST_FRAGMENT)) {
2607 		struct tipc_msg *imsg = (struct tipc_msg *)msg_data(fragm);
2608 		u32 msg_sz = msg_size(imsg);
2609 		u32 fragm_sz = msg_data_sz(fragm);
2610 		u32 exp_fragm_cnt = msg_sz/fragm_sz + !!(msg_sz % fragm_sz);
2611 		u32 max =  TIPC_MAX_USER_MSG_SIZE + LONG_H_SIZE;
2612 		if (msg_type(imsg) == TIPC_MCAST_MSG)
2613 			max = TIPC_MAX_USER_MSG_SIZE + MCAST_H_SIZE;
2614 		if (msg_size(imsg) > max) {
2615 			msg_dbg(fragm,"<REC<Oversized: ");
2616 			buf_discard(fbuf);
2617 			return 0;
2618 		}
2619 		pbuf = buf_acquire(msg_size(imsg));
2620 		if (pbuf != NULL) {
2621 			pbuf->next = *pending;
2622 			*pending = pbuf;
2623 			memcpy(pbuf->data, (unchar *)imsg, msg_data_sz(fragm));
2624 
2625 			/*  Prepare buffer for subsequent fragments. */
2626 
2627 			set_long_msg_seqno(pbuf, long_msg_seq_no);
2628 			set_fragm_size(pbuf,fragm_sz);
2629 			set_expected_frags(pbuf,exp_fragm_cnt - 1);
2630 		} else {
2631 			warn("Memory squeeze; got no defragmenting buffer\n");
2632 		}
2633 		buf_discard(fbuf);
2634 		return 0;
2635 	} else if (pbuf && (msg_type(fragm) != FIRST_FRAGMENT)) {
2636 		u32 dsz = msg_data_sz(fragm);
2637 		u32 fsz = get_fragm_size(pbuf);
2638 		u32 crs = ((msg_fragm_no(fragm) - 1) * fsz);
2639 		u32 exp_frags = get_expected_frags(pbuf) - 1;
2640 		memcpy(pbuf->data + crs, msg_data(fragm), dsz);
2641 		buf_discard(fbuf);
2642 
2643 		/* Is message complete? */
2644 
2645 		if (exp_frags == 0) {
2646 			if (prev)
2647 				prev->next = pbuf->next;
2648 			else
2649 				*pending = pbuf->next;
2650 			msg_reset_reroute_cnt(buf_msg(pbuf));
2651 			*fb = pbuf;
2652 			*m = buf_msg(pbuf);
2653 			return 1;
2654 		}
2655 		set_expected_frags(pbuf,exp_frags);
2656 		return 0;
2657 	}
2658 	dbg(" Discarding orphan fragment %x\n",fbuf);
2659 	msg_dbg(fragm,"ORPHAN:");
2660 	dbg("Pending long buffers:\n");
2661 	dbg_print_buf_chain(*pending);
2662 	buf_discard(fbuf);
2663 	return 0;
2664 }
2665 
2666 /**
2667  * link_check_defragm_bufs - flush stale incoming message fragments
2668  * @l_ptr: pointer to link
2669  */
2670 
2671 static void link_check_defragm_bufs(struct link *l_ptr)
2672 {
2673 	struct sk_buff *prev = 0;
2674 	struct sk_buff *next = 0;
2675 	struct sk_buff *buf = l_ptr->defragm_buf;
2676 
2677 	if (!buf)
2678 		return;
2679 	if (!link_working_working(l_ptr))
2680 		return;
2681 	while (buf) {
2682 		u32 cnt = get_timer_cnt(buf);
2683 
2684 		next = buf->next;
2685 		if (cnt < 4) {
2686 			incr_timer_cnt(buf);
2687 			prev = buf;
2688 		} else {
2689 			dbg(" Discarding incomplete long buffer\n");
2690 			msg_dbg(buf_msg(buf), "LONG:");
2691 			dbg_print_link(l_ptr, "curr:");
2692 			dbg("Pending long buffers:\n");
2693 			dbg_print_buf_chain(l_ptr->defragm_buf);
2694 			if (prev)
2695 				prev->next = buf->next;
2696 			else
2697 				l_ptr->defragm_buf = buf->next;
2698 			buf_discard(buf);
2699 		}
2700 		buf = next;
2701 	}
2702 }
2703 
2704 
2705 
2706 static void link_set_supervision_props(struct link *l_ptr, u32 tolerance)
2707 {
2708 	l_ptr->tolerance = tolerance;
2709 	l_ptr->continuity_interval =
2710 		((tolerance / 4) > 500) ? 500 : tolerance / 4;
2711 	l_ptr->abort_limit = tolerance / (l_ptr->continuity_interval / 4);
2712 }
2713 
2714 
2715 void tipc_link_set_queue_limits(struct link *l_ptr, u32 window)
2716 {
2717 	/* Data messages from this node, inclusive FIRST_FRAGM */
2718 	l_ptr->queue_limit[DATA_LOW] = window;
2719 	l_ptr->queue_limit[DATA_MEDIUM] = (window / 3) * 4;
2720 	l_ptr->queue_limit[DATA_HIGH] = (window / 3) * 5;
2721 	l_ptr->queue_limit[DATA_CRITICAL] = (window / 3) * 6;
2722 	/* Transiting data messages,inclusive FIRST_FRAGM */
2723 	l_ptr->queue_limit[DATA_LOW + 4] = 300;
2724 	l_ptr->queue_limit[DATA_MEDIUM + 4] = 600;
2725 	l_ptr->queue_limit[DATA_HIGH + 4] = 900;
2726 	l_ptr->queue_limit[DATA_CRITICAL + 4] = 1200;
2727 	l_ptr->queue_limit[CONN_MANAGER] = 1200;
2728 	l_ptr->queue_limit[ROUTE_DISTRIBUTOR] = 1200;
2729 	l_ptr->queue_limit[CHANGEOVER_PROTOCOL] = 2500;
2730 	l_ptr->queue_limit[NAME_DISTRIBUTOR] = 3000;
2731 	/* FRAGMENT and LAST_FRAGMENT packets */
2732 	l_ptr->queue_limit[MSG_FRAGMENTER] = 4000;
2733 }
2734 
2735 /**
2736  * link_find_link - locate link by name
2737  * @name - ptr to link name string
2738  * @node - ptr to area to be filled with ptr to associated node
2739  *
2740  * Caller must hold 'tipc_net_lock' to ensure node and bearer are not deleted;
2741  * this also prevents link deletion.
2742  *
2743  * Returns pointer to link (or 0 if invalid link name).
2744  */
2745 
2746 static struct link *link_find_link(const char *name, struct node **node)
2747 {
2748 	struct link_name link_name_parts;
2749 	struct bearer *b_ptr;
2750 	struct link *l_ptr;
2751 
2752 	if (!link_name_validate(name, &link_name_parts))
2753 		return 0;
2754 
2755 	b_ptr = tipc_bearer_find_interface(link_name_parts.if_local);
2756 	if (!b_ptr)
2757 		return 0;
2758 
2759 	*node = tipc_node_find(link_name_parts.addr_peer);
2760 	if (!*node)
2761 		return 0;
2762 
2763 	l_ptr = (*node)->links[b_ptr->identity];
2764 	if (!l_ptr || strcmp(l_ptr->name, name))
2765 		return 0;
2766 
2767 	return l_ptr;
2768 }
2769 
2770 struct sk_buff *tipc_link_cmd_config(const void *req_tlv_area, int req_tlv_space,
2771 				     u16 cmd)
2772 {
2773 	struct tipc_link_config *args;
2774         u32 new_value;
2775 	struct link *l_ptr;
2776 	struct node *node;
2777         int res;
2778 
2779 	if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_CONFIG))
2780 		return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2781 
2782 	args = (struct tipc_link_config *)TLV_DATA(req_tlv_area);
2783 	new_value = ntohl(args->value);
2784 
2785 	if (!strcmp(args->name, tipc_bclink_name)) {
2786 		if ((cmd == TIPC_CMD_SET_LINK_WINDOW) &&
2787 		    (tipc_bclink_set_queue_limits(new_value) == 0))
2788 			return tipc_cfg_reply_none();
2789 	       	return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
2790 						   " (cannot change setting on broadcast link)");
2791 	}
2792 
2793 	read_lock_bh(&tipc_net_lock);
2794 	l_ptr = link_find_link(args->name, &node);
2795 	if (!l_ptr) {
2796 		read_unlock_bh(&tipc_net_lock);
2797 	       	return tipc_cfg_reply_error_string("link not found");
2798 	}
2799 
2800 	tipc_node_lock(node);
2801 	res = -EINVAL;
2802 	switch (cmd) {
2803 	case TIPC_CMD_SET_LINK_TOL:
2804 		if ((new_value >= TIPC_MIN_LINK_TOL) &&
2805 		    (new_value <= TIPC_MAX_LINK_TOL)) {
2806 			link_set_supervision_props(l_ptr, new_value);
2807 			tipc_link_send_proto_msg(l_ptr, STATE_MSG,
2808 						 0, 0, new_value, 0, 0);
2809 			res = TIPC_OK;
2810 		}
2811 		break;
2812 	case TIPC_CMD_SET_LINK_PRI:
2813 		if ((new_value >= TIPC_MIN_LINK_PRI) &&
2814 		    (new_value <= TIPC_MAX_LINK_PRI)) {
2815 			l_ptr->priority = new_value;
2816 			tipc_link_send_proto_msg(l_ptr, STATE_MSG,
2817 						 0, 0, 0, new_value, 0);
2818 			res = TIPC_OK;
2819 		}
2820 		break;
2821 	case TIPC_CMD_SET_LINK_WINDOW:
2822 		if ((new_value >= TIPC_MIN_LINK_WIN) &&
2823 		    (new_value <= TIPC_MAX_LINK_WIN)) {
2824 			tipc_link_set_queue_limits(l_ptr, new_value);
2825 			res = TIPC_OK;
2826 		}
2827 		break;
2828 	}
2829 	tipc_node_unlock(node);
2830 
2831 	read_unlock_bh(&tipc_net_lock);
2832 	if (res)
2833 	       	return tipc_cfg_reply_error_string("cannot change link setting");
2834 
2835 	return tipc_cfg_reply_none();
2836 }
2837 
2838 /**
2839  * link_reset_statistics - reset link statistics
2840  * @l_ptr: pointer to link
2841  */
2842 
2843 static void link_reset_statistics(struct link *l_ptr)
2844 {
2845 	memset(&l_ptr->stats, 0, sizeof(l_ptr->stats));
2846 	l_ptr->stats.sent_info = l_ptr->next_out_no;
2847 	l_ptr->stats.recv_info = l_ptr->next_in_no;
2848 }
2849 
2850 struct sk_buff *tipc_link_cmd_reset_stats(const void *req_tlv_area, int req_tlv_space)
2851 {
2852 	char *link_name;
2853 	struct link *l_ptr;
2854 	struct node *node;
2855 
2856 	if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_NAME))
2857 		return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2858 
2859 	link_name = (char *)TLV_DATA(req_tlv_area);
2860 	if (!strcmp(link_name, tipc_bclink_name)) {
2861 		if (tipc_bclink_reset_stats())
2862 			return tipc_cfg_reply_error_string("link not found");
2863 		return tipc_cfg_reply_none();
2864 	}
2865 
2866 	read_lock_bh(&tipc_net_lock);
2867 	l_ptr = link_find_link(link_name, &node);
2868 	if (!l_ptr) {
2869 		read_unlock_bh(&tipc_net_lock);
2870 		return tipc_cfg_reply_error_string("link not found");
2871 	}
2872 
2873 	tipc_node_lock(node);
2874 	link_reset_statistics(l_ptr);
2875 	tipc_node_unlock(node);
2876 	read_unlock_bh(&tipc_net_lock);
2877 	return tipc_cfg_reply_none();
2878 }
2879 
2880 /**
2881  * percent - convert count to a percentage of total (rounding up or down)
2882  */
2883 
2884 static u32 percent(u32 count, u32 total)
2885 {
2886 	return (count * 100 + (total / 2)) / total;
2887 }
2888 
2889 /**
2890  * tipc_link_stats - print link statistics
2891  * @name: link name
2892  * @buf: print buffer area
2893  * @buf_size: size of print buffer area
2894  *
2895  * Returns length of print buffer data string (or 0 if error)
2896  */
2897 
2898 static int tipc_link_stats(const char *name, char *buf, const u32 buf_size)
2899 {
2900 	struct print_buf pb;
2901 	struct link *l_ptr;
2902 	struct node *node;
2903 	char *status;
2904 	u32 profile_total = 0;
2905 
2906 	if (!strcmp(name, tipc_bclink_name))
2907 		return tipc_bclink_stats(buf, buf_size);
2908 
2909 	tipc_printbuf_init(&pb, buf, buf_size);
2910 
2911 	read_lock_bh(&tipc_net_lock);
2912 	l_ptr = link_find_link(name, &node);
2913 	if (!l_ptr) {
2914 		read_unlock_bh(&tipc_net_lock);
2915 		return 0;
2916 	}
2917 	tipc_node_lock(node);
2918 
2919 	if (tipc_link_is_active(l_ptr))
2920 		status = "ACTIVE";
2921 	else if (tipc_link_is_up(l_ptr))
2922 		status = "STANDBY";
2923 	else
2924 		status = "DEFUNCT";
2925 	tipc_printf(&pb, "Link <%s>\n"
2926 		         "  %s  MTU:%u  Priority:%u  Tolerance:%u ms"
2927 		         "  Window:%u packets\n",
2928 		    l_ptr->name, status, link_max_pkt(l_ptr),
2929 		    l_ptr->priority, l_ptr->tolerance, l_ptr->queue_limit[0]);
2930 	tipc_printf(&pb, "  RX packets:%u fragments:%u/%u bundles:%u/%u\n",
2931 		    l_ptr->next_in_no - l_ptr->stats.recv_info,
2932 		    l_ptr->stats.recv_fragments,
2933 		    l_ptr->stats.recv_fragmented,
2934 		    l_ptr->stats.recv_bundles,
2935 		    l_ptr->stats.recv_bundled);
2936 	tipc_printf(&pb, "  TX packets:%u fragments:%u/%u bundles:%u/%u\n",
2937 		    l_ptr->next_out_no - l_ptr->stats.sent_info,
2938 		    l_ptr->stats.sent_fragments,
2939 		    l_ptr->stats.sent_fragmented,
2940 		    l_ptr->stats.sent_bundles,
2941 		    l_ptr->stats.sent_bundled);
2942 	profile_total = l_ptr->stats.msg_length_counts;
2943 	if (!profile_total)
2944 		profile_total = 1;
2945 	tipc_printf(&pb, "  TX profile sample:%u packets  average:%u octets\n"
2946 		         "  0-64:%u%% -256:%u%% -1024:%u%% -4096:%u%% "
2947 		         "-16354:%u%% -32768:%u%% -66000:%u%%\n",
2948 		    l_ptr->stats.msg_length_counts,
2949 		    l_ptr->stats.msg_lengths_total / profile_total,
2950 		    percent(l_ptr->stats.msg_length_profile[0], profile_total),
2951 		    percent(l_ptr->stats.msg_length_profile[1], profile_total),
2952 		    percent(l_ptr->stats.msg_length_profile[2], profile_total),
2953 		    percent(l_ptr->stats.msg_length_profile[3], profile_total),
2954 		    percent(l_ptr->stats.msg_length_profile[4], profile_total),
2955 		    percent(l_ptr->stats.msg_length_profile[5], profile_total),
2956 		    percent(l_ptr->stats.msg_length_profile[6], profile_total));
2957 	tipc_printf(&pb, "  RX states:%u probes:%u naks:%u defs:%u dups:%u\n",
2958 		    l_ptr->stats.recv_states,
2959 		    l_ptr->stats.recv_probes,
2960 		    l_ptr->stats.recv_nacks,
2961 		    l_ptr->stats.deferred_recv,
2962 		    l_ptr->stats.duplicates);
2963 	tipc_printf(&pb, "  TX states:%u probes:%u naks:%u acks:%u dups:%u\n",
2964 		    l_ptr->stats.sent_states,
2965 		    l_ptr->stats.sent_probes,
2966 		    l_ptr->stats.sent_nacks,
2967 		    l_ptr->stats.sent_acks,
2968 		    l_ptr->stats.retransmitted);
2969 	tipc_printf(&pb, "  Congestion bearer:%u link:%u  Send queue max:%u avg:%u\n",
2970 		    l_ptr->stats.bearer_congs,
2971 		    l_ptr->stats.link_congs,
2972 		    l_ptr->stats.max_queue_sz,
2973 		    l_ptr->stats.queue_sz_counts
2974 		    ? (l_ptr->stats.accu_queue_sz / l_ptr->stats.queue_sz_counts)
2975 		    : 0);
2976 
2977 	tipc_node_unlock(node);
2978 	read_unlock_bh(&tipc_net_lock);
2979 	return tipc_printbuf_validate(&pb);
2980 }
2981 
2982 #define MAX_LINK_STATS_INFO 2000
2983 
2984 struct sk_buff *tipc_link_cmd_show_stats(const void *req_tlv_area, int req_tlv_space)
2985 {
2986 	struct sk_buff *buf;
2987 	struct tlv_desc *rep_tlv;
2988 	int str_len;
2989 
2990 	if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_NAME))
2991 		return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2992 
2993 	buf = tipc_cfg_reply_alloc(TLV_SPACE(MAX_LINK_STATS_INFO));
2994 	if (!buf)
2995 		return NULL;
2996 
2997 	rep_tlv = (struct tlv_desc *)buf->data;
2998 
2999 	str_len = tipc_link_stats((char *)TLV_DATA(req_tlv_area),
3000 				  (char *)TLV_DATA(rep_tlv), MAX_LINK_STATS_INFO);
3001 	if (!str_len) {
3002 		buf_discard(buf);
3003 	       	return tipc_cfg_reply_error_string("link not found");
3004 	}
3005 
3006 	skb_put(buf, TLV_SPACE(str_len));
3007 	TLV_SET(rep_tlv, TIPC_TLV_ULTRA_STRING, NULL, str_len);
3008 
3009 	return buf;
3010 }
3011 
3012 #if 0
3013 int link_control(const char *name, u32 op, u32 val)
3014 {
3015 	int res = -EINVAL;
3016 	struct link *l_ptr;
3017 	u32 bearer_id;
3018 	struct node * node;
3019 	u32 a;
3020 
3021 	a = link_name2addr(name, &bearer_id);
3022 	read_lock_bh(&tipc_net_lock);
3023 	node = tipc_node_find(a);
3024 	if (node) {
3025 		tipc_node_lock(node);
3026 		l_ptr = node->links[bearer_id];
3027 		if (l_ptr) {
3028 			if (op == TIPC_REMOVE_LINK) {
3029 				struct bearer *b_ptr = l_ptr->b_ptr;
3030 				spin_lock_bh(&b_ptr->publ.lock);
3031 				tipc_link_delete(l_ptr);
3032 				spin_unlock_bh(&b_ptr->publ.lock);
3033 			}
3034 			if (op == TIPC_CMD_BLOCK_LINK) {
3035 				tipc_link_reset(l_ptr);
3036 				l_ptr->blocked = 1;
3037 			}
3038 			if (op == TIPC_CMD_UNBLOCK_LINK) {
3039 				l_ptr->blocked = 0;
3040 			}
3041 			res = TIPC_OK;
3042 		}
3043 		tipc_node_unlock(node);
3044 	}
3045 	read_unlock_bh(&tipc_net_lock);
3046 	return res;
3047 }
3048 #endif
3049 
3050 /**
3051  * tipc_link_get_max_pkt - get maximum packet size to use when sending to destination
3052  * @dest: network address of destination node
3053  * @selector: used to select from set of active links
3054  *
3055  * If no active link can be found, uses default maximum packet size.
3056  */
3057 
3058 u32 tipc_link_get_max_pkt(u32 dest, u32 selector)
3059 {
3060 	struct node *n_ptr;
3061 	struct link *l_ptr;
3062 	u32 res = MAX_PKT_DEFAULT;
3063 
3064 	if (dest == tipc_own_addr)
3065 		return MAX_MSG_SIZE;
3066 
3067 	read_lock_bh(&tipc_net_lock);
3068 	n_ptr = tipc_node_select(dest, selector);
3069 	if (n_ptr) {
3070 		tipc_node_lock(n_ptr);
3071 		l_ptr = n_ptr->active_links[selector & 1];
3072 		if (l_ptr)
3073 			res = link_max_pkt(l_ptr);
3074 		tipc_node_unlock(n_ptr);
3075 	}
3076 	read_unlock_bh(&tipc_net_lock);
3077 	return res;
3078 }
3079 
3080 #if 0
3081 static void link_dump_rec_queue(struct link *l_ptr)
3082 {
3083 	struct sk_buff *crs;
3084 
3085 	if (!l_ptr->oldest_deferred_in) {
3086 		info("Reception queue empty\n");
3087 		return;
3088 	}
3089 	info("Contents of Reception queue:\n");
3090 	crs = l_ptr->oldest_deferred_in;
3091 	while (crs) {
3092 		if (crs->data == (void *)0x0000a3a3) {
3093 			info("buffer %x invalid\n", crs);
3094 			return;
3095 		}
3096 		msg_dbg(buf_msg(crs), "In rec queue: \n");
3097 		crs = crs->next;
3098 	}
3099 }
3100 #endif
3101 
3102 static void link_dump_send_queue(struct link *l_ptr)
3103 {
3104 	if (l_ptr->next_out) {
3105 		info("\nContents of unsent queue:\n");
3106 		dbg_print_buf_chain(l_ptr->next_out);
3107 	}
3108 	info("\nContents of send queue:\n");
3109 	if (l_ptr->first_out) {
3110 		dbg_print_buf_chain(l_ptr->first_out);
3111 	}
3112 	info("Empty send queue\n");
3113 }
3114 
3115 static void link_print(struct link *l_ptr, struct print_buf *buf,
3116 		       const char *str)
3117 {
3118 	tipc_printf(buf, str);
3119 	if (link_reset_reset(l_ptr) || link_reset_unknown(l_ptr))
3120 		return;
3121 	tipc_printf(buf, "Link %x<%s>:",
3122 		    l_ptr->addr, l_ptr->b_ptr->publ.name);
3123 	tipc_printf(buf, ": NXO(%u):", mod(l_ptr->next_out_no));
3124 	tipc_printf(buf, "NXI(%u):", mod(l_ptr->next_in_no));
3125 	tipc_printf(buf, "SQUE");
3126 	if (l_ptr->first_out) {
3127 		tipc_printf(buf, "[%u..", msg_seqno(buf_msg(l_ptr->first_out)));
3128 		if (l_ptr->next_out)
3129 			tipc_printf(buf, "%u..",
3130 				    msg_seqno(buf_msg(l_ptr->next_out)));
3131 		tipc_printf(buf, "%u]",
3132 			    msg_seqno(buf_msg
3133 				      (l_ptr->last_out)), l_ptr->out_queue_size);
3134 		if ((mod(msg_seqno(buf_msg(l_ptr->last_out)) -
3135 			 msg_seqno(buf_msg(l_ptr->first_out)))
3136 		     != (l_ptr->out_queue_size - 1))
3137 		    || (l_ptr->last_out->next != 0)) {
3138 			tipc_printf(buf, "\nSend queue inconsistency\n");
3139 			tipc_printf(buf, "first_out= %x ", l_ptr->first_out);
3140 			tipc_printf(buf, "next_out= %x ", l_ptr->next_out);
3141 			tipc_printf(buf, "last_out= %x ", l_ptr->last_out);
3142 			link_dump_send_queue(l_ptr);
3143 		}
3144 	} else
3145 		tipc_printf(buf, "[]");
3146 	tipc_printf(buf, "SQSIZ(%u)", l_ptr->out_queue_size);
3147 	if (l_ptr->oldest_deferred_in) {
3148 		u32 o = msg_seqno(buf_msg(l_ptr->oldest_deferred_in));
3149 		u32 n = msg_seqno(buf_msg(l_ptr->newest_deferred_in));
3150 		tipc_printf(buf, ":RQUE[%u..%u]", o, n);
3151 		if (l_ptr->deferred_inqueue_sz != mod((n + 1) - o)) {
3152 			tipc_printf(buf, ":RQSIZ(%u)",
3153 				    l_ptr->deferred_inqueue_sz);
3154 		}
3155 	}
3156 	if (link_working_unknown(l_ptr))
3157 		tipc_printf(buf, ":WU");
3158 	if (link_reset_reset(l_ptr))
3159 		tipc_printf(buf, ":RR");
3160 	if (link_reset_unknown(l_ptr))
3161 		tipc_printf(buf, ":RU");
3162 	if (link_working_working(l_ptr))
3163 		tipc_printf(buf, ":WW");
3164 	tipc_printf(buf, "\n");
3165 }
3166 
3167