xref: /linux/net/tipc/link.c (revision 3b27d13940c3710a1128527c43719cb0bb05d73b)
1 /*
2  * net/tipc/link.c: TIPC link code
3  *
4  * Copyright (c) 1996-2007, 2012-2015, Ericsson AB
5  * Copyright (c) 2004-2007, 2010-2013, 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 "subscr.h"
39 #include "link.h"
40 #include "bcast.h"
41 #include "socket.h"
42 #include "name_distr.h"
43 #include "discover.h"
44 #include "netlink.h"
45 
46 #include <linux/pkt_sched.h>
47 
48 /*
49  * Error message prefixes
50  */
51 static const char *link_co_err = "Link changeover error, ";
52 static const char *link_rst_msg = "Resetting link ";
53 static const char *link_unk_evt = "Unknown link event ";
54 
55 static const struct nla_policy tipc_nl_link_policy[TIPC_NLA_LINK_MAX + 1] = {
56 	[TIPC_NLA_LINK_UNSPEC]		= { .type = NLA_UNSPEC },
57 	[TIPC_NLA_LINK_NAME] = {
58 		.type = NLA_STRING,
59 		.len = TIPC_MAX_LINK_NAME
60 	},
61 	[TIPC_NLA_LINK_MTU]		= { .type = NLA_U32 },
62 	[TIPC_NLA_LINK_BROADCAST]	= { .type = NLA_FLAG },
63 	[TIPC_NLA_LINK_UP]		= { .type = NLA_FLAG },
64 	[TIPC_NLA_LINK_ACTIVE]		= { .type = NLA_FLAG },
65 	[TIPC_NLA_LINK_PROP]		= { .type = NLA_NESTED },
66 	[TIPC_NLA_LINK_STATS]		= { .type = NLA_NESTED },
67 	[TIPC_NLA_LINK_RX]		= { .type = NLA_U32 },
68 	[TIPC_NLA_LINK_TX]		= { .type = NLA_U32 }
69 };
70 
71 /* Properties valid for media, bearar and link */
72 static const struct nla_policy tipc_nl_prop_policy[TIPC_NLA_PROP_MAX + 1] = {
73 	[TIPC_NLA_PROP_UNSPEC]		= { .type = NLA_UNSPEC },
74 	[TIPC_NLA_PROP_PRIO]		= { .type = NLA_U32 },
75 	[TIPC_NLA_PROP_TOL]		= { .type = NLA_U32 },
76 	[TIPC_NLA_PROP_WIN]		= { .type = NLA_U32 }
77 };
78 
79 /*
80  * Out-of-range value for link session numbers
81  */
82 #define INVALID_SESSION 0x10000
83 
84 /*
85  * Link state events:
86  */
87 #define  STARTING_EVT    856384768	/* link processing trigger */
88 #define  TRAFFIC_MSG_EVT 560815u	/* rx'd ??? */
89 #define  SILENCE_EVT     560817u	/* timer dicovered silence from peer */
90 
91 /*
92  * State value stored in 'failover_pkts'
93  */
94 #define FIRST_FAILOVER 0xffffu
95 
96 static void link_handle_out_of_seq_msg(struct tipc_link *link,
97 				       struct sk_buff *skb);
98 static void tipc_link_proto_rcv(struct tipc_link *link,
99 				struct sk_buff *skb);
100 static void link_set_supervision_props(struct tipc_link *l_ptr, u32 tol);
101 static void link_state_event(struct tipc_link *l_ptr, u32 event);
102 static void link_reset_statistics(struct tipc_link *l_ptr);
103 static void link_print(struct tipc_link *l_ptr, const char *str);
104 static void tipc_link_sync_xmit(struct tipc_link *l);
105 static void tipc_link_sync_rcv(struct tipc_node *n, struct sk_buff *buf);
106 static void tipc_link_input(struct tipc_link *l, struct sk_buff *skb);
107 static bool tipc_data_input(struct tipc_link *l, struct sk_buff *skb);
108 static bool tipc_link_failover_rcv(struct tipc_link *l, struct sk_buff **skb);
109 static void link_set_timer(struct tipc_link *link, unsigned long time);
110 /*
111  *  Simple link routines
112  */
113 static unsigned int align(unsigned int i)
114 {
115 	return (i + 3) & ~3u;
116 }
117 
118 static void tipc_link_release(struct kref *kref)
119 {
120 	kfree(container_of(kref, struct tipc_link, ref));
121 }
122 
123 static void tipc_link_get(struct tipc_link *l_ptr)
124 {
125 	kref_get(&l_ptr->ref);
126 }
127 
128 static void tipc_link_put(struct tipc_link *l_ptr)
129 {
130 	kref_put(&l_ptr->ref, tipc_link_release);
131 }
132 
133 static struct tipc_link *tipc_parallel_link(struct tipc_link *l)
134 {
135 	if (l->owner->active_links[0] != l)
136 		return l->owner->active_links[0];
137 	return l->owner->active_links[1];
138 }
139 
140 /*
141  *  Simple non-static link routines (i.e. referenced outside this file)
142  */
143 int tipc_link_is_up(struct tipc_link *l_ptr)
144 {
145 	if (!l_ptr)
146 		return 0;
147 	return link_working_working(l_ptr) || link_working_unknown(l_ptr);
148 }
149 
150 int tipc_link_is_active(struct tipc_link *l_ptr)
151 {
152 	return	(l_ptr->owner->active_links[0] == l_ptr) ||
153 		(l_ptr->owner->active_links[1] == l_ptr);
154 }
155 
156 /**
157  * link_timeout - handle expiration of link timer
158  * @l_ptr: pointer to link
159  */
160 static void link_timeout(unsigned long data)
161 {
162 	struct tipc_link *l_ptr = (struct tipc_link *)data;
163 	struct sk_buff *skb;
164 
165 	tipc_node_lock(l_ptr->owner);
166 
167 	/* update counters used in statistical profiling of send traffic */
168 	l_ptr->stats.accu_queue_sz += skb_queue_len(&l_ptr->transmq);
169 	l_ptr->stats.queue_sz_counts++;
170 
171 	skb = skb_peek(&l_ptr->transmq);
172 	if (skb) {
173 		struct tipc_msg *msg = buf_msg(skb);
174 		u32 length = msg_size(msg);
175 
176 		if ((msg_user(msg) == MSG_FRAGMENTER) &&
177 		    (msg_type(msg) == FIRST_FRAGMENT)) {
178 			length = msg_size(msg_get_wrapped(msg));
179 		}
180 		if (length) {
181 			l_ptr->stats.msg_lengths_total += length;
182 			l_ptr->stats.msg_length_counts++;
183 			if (length <= 64)
184 				l_ptr->stats.msg_length_profile[0]++;
185 			else if (length <= 256)
186 				l_ptr->stats.msg_length_profile[1]++;
187 			else if (length <= 1024)
188 				l_ptr->stats.msg_length_profile[2]++;
189 			else if (length <= 4096)
190 				l_ptr->stats.msg_length_profile[3]++;
191 			else if (length <= 16384)
192 				l_ptr->stats.msg_length_profile[4]++;
193 			else if (length <= 32768)
194 				l_ptr->stats.msg_length_profile[5]++;
195 			else
196 				l_ptr->stats.msg_length_profile[6]++;
197 		}
198 	}
199 
200 	/* do all other link processing performed on a periodic basis */
201 	if (l_ptr->silent_intv_cnt || tipc_bclink_acks_missing(l_ptr->owner))
202 		link_state_event(l_ptr, SILENCE_EVT);
203 	l_ptr->silent_intv_cnt++;
204 	if (skb_queue_len(&l_ptr->backlogq))
205 		tipc_link_push_packets(l_ptr);
206 	link_set_timer(l_ptr, l_ptr->keepalive_intv);
207 	tipc_node_unlock(l_ptr->owner);
208 	tipc_link_put(l_ptr);
209 }
210 
211 static void link_set_timer(struct tipc_link *link, unsigned long time)
212 {
213 	if (!mod_timer(&link->timer, jiffies + time))
214 		tipc_link_get(link);
215 }
216 
217 /**
218  * tipc_link_create - create a new link
219  * @n_ptr: pointer to associated node
220  * @b_ptr: pointer to associated bearer
221  * @media_addr: media address to use when sending messages over link
222  *
223  * Returns pointer to link.
224  */
225 struct tipc_link *tipc_link_create(struct tipc_node *n_ptr,
226 				   struct tipc_bearer *b_ptr,
227 				   const struct tipc_media_addr *media_addr)
228 {
229 	struct tipc_net *tn = net_generic(n_ptr->net, tipc_net_id);
230 	struct tipc_link *l_ptr;
231 	struct tipc_msg *msg;
232 	char *if_name;
233 	char addr_string[16];
234 	u32 peer = n_ptr->addr;
235 
236 	if (n_ptr->link_cnt >= MAX_BEARERS) {
237 		tipc_addr_string_fill(addr_string, n_ptr->addr);
238 		pr_err("Cannot establish %uth link to %s. Max %u allowed.\n",
239 		       n_ptr->link_cnt, addr_string, MAX_BEARERS);
240 		return NULL;
241 	}
242 
243 	if (n_ptr->links[b_ptr->identity]) {
244 		tipc_addr_string_fill(addr_string, n_ptr->addr);
245 		pr_err("Attempt to establish second link on <%s> to %s\n",
246 		       b_ptr->name, addr_string);
247 		return NULL;
248 	}
249 
250 	l_ptr = kzalloc(sizeof(*l_ptr), GFP_ATOMIC);
251 	if (!l_ptr) {
252 		pr_warn("Link creation failed, no memory\n");
253 		return NULL;
254 	}
255 	kref_init(&l_ptr->ref);
256 	l_ptr->addr = peer;
257 	if_name = strchr(b_ptr->name, ':') + 1;
258 	sprintf(l_ptr->name, "%u.%u.%u:%s-%u.%u.%u:unknown",
259 		tipc_zone(tn->own_addr), tipc_cluster(tn->own_addr),
260 		tipc_node(tn->own_addr),
261 		if_name,
262 		tipc_zone(peer), tipc_cluster(peer), tipc_node(peer));
263 		/* note: peer i/f name is updated by reset/activate message */
264 	memcpy(&l_ptr->media_addr, media_addr, sizeof(*media_addr));
265 	l_ptr->owner = n_ptr;
266 	l_ptr->peer_session = INVALID_SESSION;
267 	l_ptr->bearer_id = b_ptr->identity;
268 	link_set_supervision_props(l_ptr, b_ptr->tolerance);
269 	l_ptr->state = RESET_UNKNOWN;
270 
271 	l_ptr->pmsg = (struct tipc_msg *)&l_ptr->proto_msg;
272 	msg = l_ptr->pmsg;
273 	tipc_msg_init(tn->own_addr, msg, LINK_PROTOCOL, RESET_MSG, INT_H_SIZE,
274 		      l_ptr->addr);
275 	msg_set_size(msg, sizeof(l_ptr->proto_msg));
276 	msg_set_session(msg, (tn->random & 0xffff));
277 	msg_set_bearer_id(msg, b_ptr->identity);
278 	strcpy((char *)msg_data(msg), if_name);
279 	l_ptr->net_plane = b_ptr->net_plane;
280 	l_ptr->advertised_mtu = b_ptr->mtu;
281 	l_ptr->mtu = l_ptr->advertised_mtu;
282 	l_ptr->priority = b_ptr->priority;
283 	tipc_link_set_queue_limits(l_ptr, b_ptr->window);
284 	l_ptr->snd_nxt = 1;
285 	__skb_queue_head_init(&l_ptr->transmq);
286 	__skb_queue_head_init(&l_ptr->backlogq);
287 	__skb_queue_head_init(&l_ptr->deferdq);
288 	skb_queue_head_init(&l_ptr->wakeupq);
289 	skb_queue_head_init(&l_ptr->inputq);
290 	skb_queue_head_init(&l_ptr->namedq);
291 	link_reset_statistics(l_ptr);
292 	tipc_node_attach_link(n_ptr, l_ptr);
293 	setup_timer(&l_ptr->timer, link_timeout, (unsigned long)l_ptr);
294 	link_state_event(l_ptr, STARTING_EVT);
295 
296 	return l_ptr;
297 }
298 
299 /**
300  * tipc_link_delete - Delete a link
301  * @l: link to be deleted
302  */
303 void tipc_link_delete(struct tipc_link *l)
304 {
305 	tipc_link_reset(l);
306 	if (del_timer(&l->timer))
307 		tipc_link_put(l);
308 	l->flags |= LINK_STOPPED;
309 	/* Delete link now, or when timer is finished: */
310 	tipc_link_reset_fragments(l);
311 	tipc_node_detach_link(l->owner, l);
312 	tipc_link_put(l);
313 }
314 
315 void tipc_link_delete_list(struct net *net, unsigned int bearer_id)
316 {
317 	struct tipc_net *tn = net_generic(net, tipc_net_id);
318 	struct tipc_link *link;
319 	struct tipc_node *node;
320 
321 	rcu_read_lock();
322 	list_for_each_entry_rcu(node, &tn->node_list, list) {
323 		tipc_node_lock(node);
324 		link = node->links[bearer_id];
325 		if (link)
326 			tipc_link_delete(link);
327 		tipc_node_unlock(node);
328 	}
329 	rcu_read_unlock();
330 }
331 
332 /**
333  * link_schedule_user - schedule a message sender for wakeup after congestion
334  * @link: congested link
335  * @list: message that was attempted sent
336  * Create pseudo msg to send back to user when congestion abates
337  * Only consumes message if there is an error
338  */
339 static int link_schedule_user(struct tipc_link *link, struct sk_buff_head *list)
340 {
341 	struct tipc_msg *msg = buf_msg(skb_peek(list));
342 	int imp = msg_importance(msg);
343 	u32 oport = msg_origport(msg);
344 	u32 addr = link_own_addr(link);
345 	struct sk_buff *skb;
346 
347 	/* This really cannot happen...  */
348 	if (unlikely(imp > TIPC_CRITICAL_IMPORTANCE)) {
349 		pr_warn("%s<%s>, send queue full", link_rst_msg, link->name);
350 		tipc_link_reset(link);
351 		goto err;
352 	}
353 	/* Non-blocking sender: */
354 	if (TIPC_SKB_CB(skb_peek(list))->wakeup_pending)
355 		return -ELINKCONG;
356 
357 	/* Create and schedule wakeup pseudo message */
358 	skb = tipc_msg_create(SOCK_WAKEUP, 0, INT_H_SIZE, 0,
359 			      addr, addr, oport, 0, 0);
360 	if (!skb)
361 		goto err;
362 	TIPC_SKB_CB(skb)->chain_sz = skb_queue_len(list);
363 	TIPC_SKB_CB(skb)->chain_imp = imp;
364 	skb_queue_tail(&link->wakeupq, skb);
365 	link->stats.link_congs++;
366 	return -ELINKCONG;
367 err:
368 	__skb_queue_purge(list);
369 	return -ENOBUFS;
370 }
371 
372 /**
373  * link_prepare_wakeup - prepare users for wakeup after congestion
374  * @link: congested link
375  * Move a number of waiting users, as permitted by available space in
376  * the send queue, from link wait queue to node wait queue for wakeup
377  */
378 void link_prepare_wakeup(struct tipc_link *l)
379 {
380 	int pnd[TIPC_SYSTEM_IMPORTANCE + 1] = {0,};
381 	int imp, lim;
382 	struct sk_buff *skb, *tmp;
383 
384 	skb_queue_walk_safe(&l->wakeupq, skb, tmp) {
385 		imp = TIPC_SKB_CB(skb)->chain_imp;
386 		lim = l->window + l->backlog[imp].limit;
387 		pnd[imp] += TIPC_SKB_CB(skb)->chain_sz;
388 		if ((pnd[imp] + l->backlog[imp].len) >= lim)
389 			break;
390 		skb_unlink(skb, &l->wakeupq);
391 		skb_queue_tail(&l->inputq, skb);
392 		l->owner->inputq = &l->inputq;
393 		l->owner->action_flags |= TIPC_MSG_EVT;
394 	}
395 }
396 
397 /**
398  * tipc_link_reset_fragments - purge link's inbound message fragments queue
399  * @l_ptr: pointer to link
400  */
401 void tipc_link_reset_fragments(struct tipc_link *l_ptr)
402 {
403 	kfree_skb(l_ptr->reasm_buf);
404 	l_ptr->reasm_buf = NULL;
405 }
406 
407 void tipc_link_purge_backlog(struct tipc_link *l)
408 {
409 	__skb_queue_purge(&l->backlogq);
410 	l->backlog[TIPC_LOW_IMPORTANCE].len = 0;
411 	l->backlog[TIPC_MEDIUM_IMPORTANCE].len = 0;
412 	l->backlog[TIPC_HIGH_IMPORTANCE].len = 0;
413 	l->backlog[TIPC_CRITICAL_IMPORTANCE].len = 0;
414 	l->backlog[TIPC_SYSTEM_IMPORTANCE].len = 0;
415 }
416 
417 /**
418  * tipc_link_purge_queues - purge all pkt queues associated with link
419  * @l_ptr: pointer to link
420  */
421 void tipc_link_purge_queues(struct tipc_link *l_ptr)
422 {
423 	__skb_queue_purge(&l_ptr->deferdq);
424 	__skb_queue_purge(&l_ptr->transmq);
425 	tipc_link_purge_backlog(l_ptr);
426 	tipc_link_reset_fragments(l_ptr);
427 }
428 
429 void tipc_link_reset(struct tipc_link *l_ptr)
430 {
431 	u32 prev_state = l_ptr->state;
432 	int was_active_link = tipc_link_is_active(l_ptr);
433 	struct tipc_node *owner = l_ptr->owner;
434 	struct tipc_link *pl = tipc_parallel_link(l_ptr);
435 
436 	msg_set_session(l_ptr->pmsg, ((msg_session(l_ptr->pmsg) + 1) & 0xffff));
437 
438 	/* Link is down, accept any session */
439 	l_ptr->peer_session = INVALID_SESSION;
440 
441 	/* Prepare for renewed mtu size negotiation */
442 	l_ptr->mtu = l_ptr->advertised_mtu;
443 
444 	l_ptr->state = RESET_UNKNOWN;
445 
446 	if ((prev_state == RESET_UNKNOWN) || (prev_state == RESET_RESET))
447 		return;
448 
449 	tipc_node_link_down(l_ptr->owner, l_ptr);
450 	tipc_bearer_remove_dest(owner->net, l_ptr->bearer_id, l_ptr->addr);
451 
452 	if (was_active_link && tipc_node_is_up(l_ptr->owner) && (pl != l_ptr)) {
453 		l_ptr->flags |= LINK_FAILINGOVER;
454 		l_ptr->failover_checkpt = l_ptr->rcv_nxt;
455 		pl->failover_pkts = FIRST_FAILOVER;
456 		pl->failover_checkpt = l_ptr->rcv_nxt;
457 		pl->failover_skb = l_ptr->reasm_buf;
458 	} else {
459 		kfree_skb(l_ptr->reasm_buf);
460 	}
461 	/* Clean up all queues, except inputq: */
462 	__skb_queue_purge(&l_ptr->transmq);
463 	__skb_queue_purge(&l_ptr->deferdq);
464 	if (!owner->inputq)
465 		owner->inputq = &l_ptr->inputq;
466 	skb_queue_splice_init(&l_ptr->wakeupq, owner->inputq);
467 	if (!skb_queue_empty(owner->inputq))
468 		owner->action_flags |= TIPC_MSG_EVT;
469 	tipc_link_purge_backlog(l_ptr);
470 	l_ptr->reasm_buf = NULL;
471 	l_ptr->rcv_unacked = 0;
472 	l_ptr->snd_nxt = 1;
473 	l_ptr->silent_intv_cnt = 0;
474 	l_ptr->stale_count = 0;
475 	link_reset_statistics(l_ptr);
476 }
477 
478 static void link_activate(struct tipc_link *link)
479 {
480 	struct tipc_node *node = link->owner;
481 
482 	link->rcv_nxt = 1;
483 	link->stats.recv_info = 1;
484 	link->silent_intv_cnt = 0;
485 	tipc_node_link_up(node, link);
486 	tipc_bearer_add_dest(node->net, link->bearer_id, link->addr);
487 }
488 
489 /**
490  * link_state_event - link finite state machine
491  * @l_ptr: pointer to link
492  * @event: state machine event to process
493  */
494 static void link_state_event(struct tipc_link *l_ptr, unsigned int event)
495 {
496 	struct tipc_link *other;
497 	unsigned long timer_intv = l_ptr->keepalive_intv;
498 
499 	if (l_ptr->flags & LINK_STOPPED)
500 		return;
501 
502 	if (!(l_ptr->flags & LINK_STARTED) && (event != STARTING_EVT))
503 		return;		/* Not yet. */
504 
505 	if (l_ptr->flags & LINK_FAILINGOVER)
506 		return;
507 
508 	switch (l_ptr->state) {
509 	case WORKING_WORKING:
510 		switch (event) {
511 		case TRAFFIC_MSG_EVT:
512 		case ACTIVATE_MSG:
513 			l_ptr->silent_intv_cnt = 0;
514 			break;
515 		case SILENCE_EVT:
516 			if (!l_ptr->silent_intv_cnt) {
517 				if (tipc_bclink_acks_missing(l_ptr->owner))
518 					tipc_link_proto_xmit(l_ptr, STATE_MSG,
519 							     0, 0, 0, 0);
520 				break;
521 			}
522 			l_ptr->state = WORKING_UNKNOWN;
523 			tipc_link_proto_xmit(l_ptr, STATE_MSG, 1, 0, 0, 0);
524 			break;
525 		case RESET_MSG:
526 			pr_debug("%s<%s>, requested by peer\n",
527 				 link_rst_msg, l_ptr->name);
528 			tipc_link_reset(l_ptr);
529 			l_ptr->state = RESET_RESET;
530 			tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
531 					     0, 0, 0, 0);
532 			break;
533 		default:
534 			pr_debug("%s%u in WW state\n", link_unk_evt, event);
535 		}
536 		break;
537 	case WORKING_UNKNOWN:
538 		switch (event) {
539 		case TRAFFIC_MSG_EVT:
540 		case ACTIVATE_MSG:
541 			l_ptr->state = WORKING_WORKING;
542 			l_ptr->silent_intv_cnt = 0;
543 			break;
544 		case RESET_MSG:
545 			pr_debug("%s<%s>, requested by peer while probing\n",
546 				 link_rst_msg, l_ptr->name);
547 			tipc_link_reset(l_ptr);
548 			l_ptr->state = RESET_RESET;
549 			tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
550 					     0, 0, 0, 0);
551 			break;
552 		case SILENCE_EVT:
553 			if (!l_ptr->silent_intv_cnt) {
554 				l_ptr->state = WORKING_WORKING;
555 				if (tipc_bclink_acks_missing(l_ptr->owner))
556 					tipc_link_proto_xmit(l_ptr, STATE_MSG,
557 							     0, 0, 0, 0);
558 			} else if (l_ptr->silent_intv_cnt <
559 				   l_ptr->abort_limit) {
560 				tipc_link_proto_xmit(l_ptr, STATE_MSG,
561 						     1, 0, 0, 0);
562 			} else {	/* Link has failed */
563 				pr_debug("%s<%s>, peer not responding\n",
564 					 link_rst_msg, l_ptr->name);
565 				tipc_link_reset(l_ptr);
566 				l_ptr->state = RESET_UNKNOWN;
567 				tipc_link_proto_xmit(l_ptr, RESET_MSG,
568 						     0, 0, 0, 0);
569 			}
570 			break;
571 		default:
572 			pr_err("%s%u in WU state\n", link_unk_evt, event);
573 		}
574 		break;
575 	case RESET_UNKNOWN:
576 		switch (event) {
577 		case TRAFFIC_MSG_EVT:
578 			break;
579 		case ACTIVATE_MSG:
580 			other = l_ptr->owner->active_links[0];
581 			if (other && link_working_unknown(other))
582 				break;
583 			l_ptr->state = WORKING_WORKING;
584 			link_activate(l_ptr);
585 			tipc_link_proto_xmit(l_ptr, STATE_MSG, 1, 0, 0, 0);
586 			if (l_ptr->owner->working_links == 1)
587 				tipc_link_sync_xmit(l_ptr);
588 			break;
589 		case RESET_MSG:
590 			l_ptr->state = RESET_RESET;
591 			tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
592 					     1, 0, 0, 0);
593 			break;
594 		case STARTING_EVT:
595 			l_ptr->flags |= LINK_STARTED;
596 			link_set_timer(l_ptr, timer_intv);
597 			break;
598 		case SILENCE_EVT:
599 			tipc_link_proto_xmit(l_ptr, RESET_MSG, 0, 0, 0, 0);
600 			break;
601 		default:
602 			pr_err("%s%u in RU state\n", link_unk_evt, event);
603 		}
604 		break;
605 	case RESET_RESET:
606 		switch (event) {
607 		case TRAFFIC_MSG_EVT:
608 		case ACTIVATE_MSG:
609 			other = l_ptr->owner->active_links[0];
610 			if (other && link_working_unknown(other))
611 				break;
612 			l_ptr->state = WORKING_WORKING;
613 			link_activate(l_ptr);
614 			tipc_link_proto_xmit(l_ptr, STATE_MSG, 1, 0, 0, 0);
615 			if (l_ptr->owner->working_links == 1)
616 				tipc_link_sync_xmit(l_ptr);
617 			break;
618 		case RESET_MSG:
619 			break;
620 		case SILENCE_EVT:
621 			tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
622 					     0, 0, 0, 0);
623 			break;
624 		default:
625 			pr_err("%s%u in RR state\n", link_unk_evt, event);
626 		}
627 		break;
628 	default:
629 		pr_err("Unknown link state %u/%u\n", l_ptr->state, event);
630 	}
631 }
632 
633 /**
634  * __tipc_link_xmit(): same as tipc_link_xmit, but destlink is known & locked
635  * @link: link to use
636  * @list: chain of buffers containing message
637  *
638  * Consumes the buffer chain, except when returning -ELINKCONG,
639  * since the caller then may want to make more send attempts.
640  * Returns 0 if success, or errno: -ELINKCONG, -EMSGSIZE or -ENOBUFS
641  * Messages at TIPC_SYSTEM_IMPORTANCE are always accepted
642  */
643 int __tipc_link_xmit(struct net *net, struct tipc_link *link,
644 		     struct sk_buff_head *list)
645 {
646 	struct tipc_msg *msg = buf_msg(skb_peek(list));
647 	unsigned int maxwin = link->window;
648 	unsigned int i, imp = msg_importance(msg);
649 	uint mtu = link->mtu;
650 	u16 ack = mod(link->rcv_nxt - 1);
651 	u16 seqno = link->snd_nxt;
652 	u16 bc_last_in = link->owner->bclink.last_in;
653 	struct tipc_media_addr *addr = &link->media_addr;
654 	struct sk_buff_head *transmq = &link->transmq;
655 	struct sk_buff_head *backlogq = &link->backlogq;
656 	struct sk_buff *skb, *bskb;
657 
658 	/* Match msg importance against this and all higher backlog limits: */
659 	for (i = imp; i <= TIPC_SYSTEM_IMPORTANCE; i++) {
660 		if (unlikely(link->backlog[i].len >= link->backlog[i].limit))
661 			return link_schedule_user(link, list);
662 	}
663 	if (unlikely(msg_size(msg) > mtu)) {
664 		__skb_queue_purge(list);
665 		return -EMSGSIZE;
666 	}
667 	/* Prepare each packet for sending, and add to relevant queue: */
668 	while (skb_queue_len(list)) {
669 		skb = skb_peek(list);
670 		msg = buf_msg(skb);
671 		msg_set_seqno(msg, seqno);
672 		msg_set_ack(msg, ack);
673 		msg_set_bcast_ack(msg, bc_last_in);
674 
675 		if (likely(skb_queue_len(transmq) < maxwin)) {
676 			__skb_dequeue(list);
677 			__skb_queue_tail(transmq, skb);
678 			tipc_bearer_send(net, link->bearer_id, skb, addr);
679 			link->rcv_unacked = 0;
680 			seqno++;
681 			continue;
682 		}
683 		if (tipc_msg_bundle(skb_peek_tail(backlogq), msg, mtu)) {
684 			kfree_skb(__skb_dequeue(list));
685 			link->stats.sent_bundled++;
686 			continue;
687 		}
688 		if (tipc_msg_make_bundle(&bskb, msg, mtu, link->addr)) {
689 			kfree_skb(__skb_dequeue(list));
690 			__skb_queue_tail(backlogq, bskb);
691 			link->backlog[msg_importance(buf_msg(bskb))].len++;
692 			link->stats.sent_bundled++;
693 			link->stats.sent_bundles++;
694 			continue;
695 		}
696 		link->backlog[imp].len += skb_queue_len(list);
697 		skb_queue_splice_tail_init(list, backlogq);
698 	}
699 	link->snd_nxt = seqno;
700 	return 0;
701 }
702 
703 static void skb2list(struct sk_buff *skb, struct sk_buff_head *list)
704 {
705 	skb_queue_head_init(list);
706 	__skb_queue_tail(list, skb);
707 }
708 
709 static int __tipc_link_xmit_skb(struct tipc_link *link, struct sk_buff *skb)
710 {
711 	struct sk_buff_head head;
712 
713 	skb2list(skb, &head);
714 	return __tipc_link_xmit(link->owner->net, link, &head);
715 }
716 
717 /* tipc_link_xmit_skb(): send single buffer to destination
718  * Buffers sent via this functon are generally TIPC_SYSTEM_IMPORTANCE
719  * messages, which will not be rejected
720  * The only exception is datagram messages rerouted after secondary
721  * lookup, which are rare and safe to dispose of anyway.
722  * TODO: Return real return value, and let callers use
723  * tipc_wait_for_sendpkt() where applicable
724  */
725 int tipc_link_xmit_skb(struct net *net, struct sk_buff *skb, u32 dnode,
726 		       u32 selector)
727 {
728 	struct sk_buff_head head;
729 	int rc;
730 
731 	skb2list(skb, &head);
732 	rc = tipc_link_xmit(net, &head, dnode, selector);
733 	if (rc == -ELINKCONG)
734 		kfree_skb(skb);
735 	return 0;
736 }
737 
738 /**
739  * tipc_link_xmit() is the general link level function for message sending
740  * @net: the applicable net namespace
741  * @list: chain of buffers containing message
742  * @dsz: amount of user data to be sent
743  * @dnode: address of destination node
744  * @selector: a number used for deterministic link selection
745  * Consumes the buffer chain, except when returning -ELINKCONG
746  * Returns 0 if success, otherwise errno: -ELINKCONG,-EHOSTUNREACH,-EMSGSIZE
747  */
748 int tipc_link_xmit(struct net *net, struct sk_buff_head *list, u32 dnode,
749 		   u32 selector)
750 {
751 	struct tipc_link *link = NULL;
752 	struct tipc_node *node;
753 	int rc = -EHOSTUNREACH;
754 
755 	node = tipc_node_find(net, dnode);
756 	if (node) {
757 		tipc_node_lock(node);
758 		link = node->active_links[selector & 1];
759 		if (link)
760 			rc = __tipc_link_xmit(net, link, list);
761 		tipc_node_unlock(node);
762 		tipc_node_put(node);
763 	}
764 	if (link)
765 		return rc;
766 
767 	if (likely(in_own_node(net, dnode))) {
768 		tipc_sk_rcv(net, list);
769 		return 0;
770 	}
771 
772 	__skb_queue_purge(list);
773 	return rc;
774 }
775 
776 /*
777  * tipc_link_sync_xmit - synchronize broadcast link endpoints.
778  *
779  * Give a newly added peer node the sequence number where it should
780  * start receiving and acking broadcast packets.
781  *
782  * Called with node locked
783  */
784 static void tipc_link_sync_xmit(struct tipc_link *link)
785 {
786 	struct sk_buff *skb;
787 	struct tipc_msg *msg;
788 
789 	skb = tipc_buf_acquire(INT_H_SIZE);
790 	if (!skb)
791 		return;
792 
793 	msg = buf_msg(skb);
794 	tipc_msg_init(link_own_addr(link), msg, BCAST_PROTOCOL, STATE_MSG,
795 		      INT_H_SIZE, link->addr);
796 	msg_set_last_bcast(msg, link->owner->bclink.acked);
797 	__tipc_link_xmit_skb(link, skb);
798 }
799 
800 /*
801  * tipc_link_sync_rcv - synchronize broadcast link endpoints.
802  * Receive the sequence number where we should start receiving and
803  * acking broadcast packets from a newly added peer node, and open
804  * up for reception of such packets.
805  *
806  * Called with node locked
807  */
808 static void tipc_link_sync_rcv(struct tipc_node *n, struct sk_buff *buf)
809 {
810 	struct tipc_msg *msg = buf_msg(buf);
811 
812 	n->bclink.last_sent = n->bclink.last_in = msg_last_bcast(msg);
813 	n->bclink.recv_permitted = true;
814 	kfree_skb(buf);
815 }
816 
817 /*
818  * tipc_link_push_packets - push unsent packets to bearer
819  *
820  * Push out the unsent messages of a link where congestion
821  * has abated. Node is locked.
822  *
823  * Called with node locked
824  */
825 void tipc_link_push_packets(struct tipc_link *link)
826 {
827 	struct sk_buff *skb;
828 	struct tipc_msg *msg;
829 	u16 seqno = link->snd_nxt;
830 	u16 ack = mod(link->rcv_nxt - 1);
831 
832 	while (skb_queue_len(&link->transmq) < link->window) {
833 		skb = __skb_dequeue(&link->backlogq);
834 		if (!skb)
835 			break;
836 		msg = buf_msg(skb);
837 		link->backlog[msg_importance(msg)].len--;
838 		msg_set_ack(msg, ack);
839 		msg_set_seqno(msg, seqno);
840 		seqno = mod(seqno + 1);
841 		msg_set_bcast_ack(msg, link->owner->bclink.last_in);
842 		link->rcv_unacked = 0;
843 		__skb_queue_tail(&link->transmq, skb);
844 		tipc_bearer_send(link->owner->net, link->bearer_id,
845 				 skb, &link->media_addr);
846 	}
847 	link->snd_nxt = seqno;
848 }
849 
850 void tipc_link_reset_all(struct tipc_node *node)
851 {
852 	char addr_string[16];
853 	u32 i;
854 
855 	tipc_node_lock(node);
856 
857 	pr_warn("Resetting all links to %s\n",
858 		tipc_addr_string_fill(addr_string, node->addr));
859 
860 	for (i = 0; i < MAX_BEARERS; i++) {
861 		if (node->links[i]) {
862 			link_print(node->links[i], "Resetting link\n");
863 			tipc_link_reset(node->links[i]);
864 		}
865 	}
866 
867 	tipc_node_unlock(node);
868 }
869 
870 static void link_retransmit_failure(struct tipc_link *l_ptr,
871 				    struct sk_buff *buf)
872 {
873 	struct tipc_msg *msg = buf_msg(buf);
874 	struct net *net = l_ptr->owner->net;
875 
876 	pr_warn("Retransmission failure on link <%s>\n", l_ptr->name);
877 
878 	if (l_ptr->addr) {
879 		/* Handle failure on standard link */
880 		link_print(l_ptr, "Resetting link\n");
881 		tipc_link_reset(l_ptr);
882 
883 	} else {
884 		/* Handle failure on broadcast link */
885 		struct tipc_node *n_ptr;
886 		char addr_string[16];
887 
888 		pr_info("Msg seq number: %u,  ", msg_seqno(msg));
889 		pr_cont("Outstanding acks: %lu\n",
890 			(unsigned long) TIPC_SKB_CB(buf)->handle);
891 
892 		n_ptr = tipc_bclink_retransmit_to(net);
893 
894 		tipc_addr_string_fill(addr_string, n_ptr->addr);
895 		pr_info("Broadcast link info for %s\n", addr_string);
896 		pr_info("Reception permitted: %d,  Acked: %u\n",
897 			n_ptr->bclink.recv_permitted,
898 			n_ptr->bclink.acked);
899 		pr_info("Last in: %u,  Oos state: %u,  Last sent: %u\n",
900 			n_ptr->bclink.last_in,
901 			n_ptr->bclink.oos_state,
902 			n_ptr->bclink.last_sent);
903 
904 		n_ptr->action_flags |= TIPC_BCAST_RESET;
905 		l_ptr->stale_count = 0;
906 	}
907 }
908 
909 void tipc_link_retransmit(struct tipc_link *l_ptr, struct sk_buff *skb,
910 			  u32 retransmits)
911 {
912 	struct tipc_msg *msg;
913 
914 	if (!skb)
915 		return;
916 
917 	msg = buf_msg(skb);
918 
919 	/* Detect repeated retransmit failures */
920 	if (l_ptr->last_retransm == msg_seqno(msg)) {
921 		if (++l_ptr->stale_count > 100) {
922 			link_retransmit_failure(l_ptr, skb);
923 			return;
924 		}
925 	} else {
926 		l_ptr->last_retransm = msg_seqno(msg);
927 		l_ptr->stale_count = 1;
928 	}
929 
930 	skb_queue_walk_from(&l_ptr->transmq, skb) {
931 		if (!retransmits)
932 			break;
933 		msg = buf_msg(skb);
934 		msg_set_ack(msg, mod(l_ptr->rcv_nxt - 1));
935 		msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
936 		tipc_bearer_send(l_ptr->owner->net, l_ptr->bearer_id, skb,
937 				 &l_ptr->media_addr);
938 		retransmits--;
939 		l_ptr->stats.retransmitted++;
940 	}
941 }
942 
943 /* link_synch(): check if all packets arrived before the synch
944  *               point have been consumed
945  * Returns true if the parallel links are synched, otherwise false
946  */
947 static bool link_synch(struct tipc_link *l)
948 {
949 	unsigned int post_synch;
950 	struct tipc_link *pl;
951 
952 	pl  = tipc_parallel_link(l);
953 	if (pl == l)
954 		goto synched;
955 
956 	/* Was last pre-synch packet added to input queue ? */
957 	if (less_eq(pl->rcv_nxt, l->synch_point))
958 		return false;
959 
960 	/* Is it still in the input queue ? */
961 	post_synch = mod(pl->rcv_nxt - l->synch_point) - 1;
962 	if (skb_queue_len(&pl->inputq) > post_synch)
963 		return false;
964 synched:
965 	l->flags &= ~LINK_SYNCHING;
966 	return true;
967 }
968 
969 static void link_retrieve_defq(struct tipc_link *link,
970 			       struct sk_buff_head *list)
971 {
972 	u16 seq_no;
973 
974 	if (skb_queue_empty(&link->deferdq))
975 		return;
976 
977 	seq_no = buf_seqno(skb_peek(&link->deferdq));
978 	if (seq_no == link->rcv_nxt)
979 		skb_queue_splice_tail_init(&link->deferdq, list);
980 }
981 
982 /**
983  * tipc_rcv - process TIPC packets/messages arriving from off-node
984  * @net: the applicable net namespace
985  * @skb: TIPC packet
986  * @b_ptr: pointer to bearer message arrived on
987  *
988  * Invoked with no locks held.  Bearer pointer must point to a valid bearer
989  * structure (i.e. cannot be NULL), but bearer can be inactive.
990  */
991 void tipc_rcv(struct net *net, struct sk_buff *skb, struct tipc_bearer *b_ptr)
992 {
993 	struct tipc_net *tn = net_generic(net, tipc_net_id);
994 	struct sk_buff_head head;
995 	struct tipc_node *n_ptr;
996 	struct tipc_link *l_ptr;
997 	struct sk_buff *skb1, *tmp;
998 	struct tipc_msg *msg;
999 	u16 seq_no;
1000 	u16 ackd;
1001 	u32 released;
1002 
1003 	skb2list(skb, &head);
1004 
1005 	while ((skb = __skb_dequeue(&head))) {
1006 		/* Ensure message is well-formed */
1007 		if (unlikely(!tipc_msg_validate(skb)))
1008 			goto discard;
1009 
1010 		/* Handle arrival of a non-unicast link message */
1011 		msg = buf_msg(skb);
1012 		if (unlikely(msg_non_seq(msg))) {
1013 			if (msg_user(msg) ==  LINK_CONFIG)
1014 				tipc_disc_rcv(net, skb, b_ptr);
1015 			else
1016 				tipc_bclink_rcv(net, skb);
1017 			continue;
1018 		}
1019 
1020 		/* Discard unicast link messages destined for another node */
1021 		if (unlikely(!msg_short(msg) &&
1022 			     (msg_destnode(msg) != tn->own_addr)))
1023 			goto discard;
1024 
1025 		/* Locate neighboring node that sent message */
1026 		n_ptr = tipc_node_find(net, msg_prevnode(msg));
1027 		if (unlikely(!n_ptr))
1028 			goto discard;
1029 
1030 		tipc_node_lock(n_ptr);
1031 		/* Locate unicast link endpoint that should handle message */
1032 		l_ptr = n_ptr->links[b_ptr->identity];
1033 		if (unlikely(!l_ptr))
1034 			goto unlock;
1035 
1036 		/* Verify that communication with node is currently allowed */
1037 		if ((n_ptr->action_flags & TIPC_WAIT_PEER_LINKS_DOWN) &&
1038 		    msg_user(msg) == LINK_PROTOCOL &&
1039 		    (msg_type(msg) == RESET_MSG ||
1040 		    msg_type(msg) == ACTIVATE_MSG) &&
1041 		    !msg_redundant_link(msg))
1042 			n_ptr->action_flags &= ~TIPC_WAIT_PEER_LINKS_DOWN;
1043 
1044 		if (tipc_node_blocked(n_ptr))
1045 			goto unlock;
1046 
1047 		/* Validate message sequence number info */
1048 		seq_no = msg_seqno(msg);
1049 		ackd = msg_ack(msg);
1050 
1051 		/* Release acked messages */
1052 		if (unlikely(n_ptr->bclink.acked != msg_bcast_ack(msg)))
1053 			tipc_bclink_acknowledge(n_ptr, msg_bcast_ack(msg));
1054 
1055 		released = 0;
1056 		skb_queue_walk_safe(&l_ptr->transmq, skb1, tmp) {
1057 			if (more(buf_seqno(skb1), ackd))
1058 				break;
1059 			 __skb_unlink(skb1, &l_ptr->transmq);
1060 			 kfree_skb(skb1);
1061 			 released = 1;
1062 		}
1063 
1064 		/* Try sending any messages link endpoint has pending */
1065 		if (unlikely(skb_queue_len(&l_ptr->backlogq)))
1066 			tipc_link_push_packets(l_ptr);
1067 
1068 		if (released && !skb_queue_empty(&l_ptr->wakeupq))
1069 			link_prepare_wakeup(l_ptr);
1070 
1071 		/* Process the incoming packet */
1072 		if (unlikely(!link_working_working(l_ptr))) {
1073 			if (msg_user(msg) == LINK_PROTOCOL) {
1074 				tipc_link_proto_rcv(l_ptr, skb);
1075 				link_retrieve_defq(l_ptr, &head);
1076 				skb = NULL;
1077 				goto unlock;
1078 			}
1079 
1080 			/* Traffic message. Conditionally activate link */
1081 			link_state_event(l_ptr, TRAFFIC_MSG_EVT);
1082 
1083 			if (link_working_working(l_ptr)) {
1084 				/* Re-insert buffer in front of queue */
1085 				__skb_queue_head(&head, skb);
1086 				skb = NULL;
1087 				goto unlock;
1088 			}
1089 			goto unlock;
1090 		}
1091 
1092 		/* Link is now in state WORKING_WORKING */
1093 		if (unlikely(seq_no != l_ptr->rcv_nxt)) {
1094 			link_handle_out_of_seq_msg(l_ptr, skb);
1095 			link_retrieve_defq(l_ptr, &head);
1096 			skb = NULL;
1097 			goto unlock;
1098 		}
1099 		l_ptr->silent_intv_cnt = 0;
1100 
1101 		/* Synchronize with parallel link if applicable */
1102 		if (unlikely((l_ptr->flags & LINK_SYNCHING) && !msg_dup(msg))) {
1103 			if (!link_synch(l_ptr))
1104 				goto unlock;
1105 		}
1106 		l_ptr->rcv_nxt++;
1107 		if (unlikely(!skb_queue_empty(&l_ptr->deferdq)))
1108 			link_retrieve_defq(l_ptr, &head);
1109 		if (unlikely(++l_ptr->rcv_unacked >= TIPC_MIN_LINK_WIN)) {
1110 			l_ptr->stats.sent_acks++;
1111 			tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, 0, 0, 0);
1112 		}
1113 		tipc_link_input(l_ptr, skb);
1114 		skb = NULL;
1115 unlock:
1116 		tipc_node_unlock(n_ptr);
1117 		tipc_node_put(n_ptr);
1118 discard:
1119 		if (unlikely(skb))
1120 			kfree_skb(skb);
1121 	}
1122 }
1123 
1124 /* tipc_data_input - deliver data and name distr msgs to upper layer
1125  *
1126  * Consumes buffer if message is of right type
1127  * Node lock must be held
1128  */
1129 static bool tipc_data_input(struct tipc_link *link, struct sk_buff *skb)
1130 {
1131 	struct tipc_node *node = link->owner;
1132 	struct tipc_msg *msg = buf_msg(skb);
1133 	u32 dport = msg_destport(msg);
1134 
1135 	switch (msg_user(msg)) {
1136 	case TIPC_LOW_IMPORTANCE:
1137 	case TIPC_MEDIUM_IMPORTANCE:
1138 	case TIPC_HIGH_IMPORTANCE:
1139 	case TIPC_CRITICAL_IMPORTANCE:
1140 	case CONN_MANAGER:
1141 		if (tipc_skb_queue_tail(&link->inputq, skb, dport)) {
1142 			node->inputq = &link->inputq;
1143 			node->action_flags |= TIPC_MSG_EVT;
1144 		}
1145 		return true;
1146 	case NAME_DISTRIBUTOR:
1147 		node->bclink.recv_permitted = true;
1148 		node->namedq = &link->namedq;
1149 		skb_queue_tail(&link->namedq, skb);
1150 		if (skb_queue_len(&link->namedq) == 1)
1151 			node->action_flags |= TIPC_NAMED_MSG_EVT;
1152 		return true;
1153 	case MSG_BUNDLER:
1154 	case TUNNEL_PROTOCOL:
1155 	case MSG_FRAGMENTER:
1156 	case BCAST_PROTOCOL:
1157 		return false;
1158 	default:
1159 		pr_warn("Dropping received illegal msg type\n");
1160 		kfree_skb(skb);
1161 		return false;
1162 	};
1163 }
1164 
1165 /* tipc_link_input - process packet that has passed link protocol check
1166  *
1167  * Consumes buffer
1168  * Node lock must be held
1169  */
1170 static void tipc_link_input(struct tipc_link *link, struct sk_buff *skb)
1171 {
1172 	struct tipc_node *node = link->owner;
1173 	struct tipc_msg *msg = buf_msg(skb);
1174 	struct sk_buff *iskb;
1175 	int pos = 0;
1176 
1177 	if (likely(tipc_data_input(link, skb)))
1178 		return;
1179 
1180 	switch (msg_user(msg)) {
1181 	case TUNNEL_PROTOCOL:
1182 		if (msg_dup(msg)) {
1183 			link->flags |= LINK_SYNCHING;
1184 			link->synch_point = msg_seqno(msg_get_wrapped(msg));
1185 			kfree_skb(skb);
1186 			break;
1187 		}
1188 		if (!tipc_link_failover_rcv(link, &skb))
1189 			break;
1190 		if (msg_user(buf_msg(skb)) != MSG_BUNDLER) {
1191 			tipc_data_input(link, skb);
1192 			break;
1193 		}
1194 	case MSG_BUNDLER:
1195 		link->stats.recv_bundles++;
1196 		link->stats.recv_bundled += msg_msgcnt(msg);
1197 
1198 		while (tipc_msg_extract(skb, &iskb, &pos))
1199 			tipc_data_input(link, iskb);
1200 		break;
1201 	case MSG_FRAGMENTER:
1202 		link->stats.recv_fragments++;
1203 		if (tipc_buf_append(&link->reasm_buf, &skb)) {
1204 			link->stats.recv_fragmented++;
1205 			tipc_data_input(link, skb);
1206 		} else if (!link->reasm_buf) {
1207 			tipc_link_reset(link);
1208 		}
1209 		break;
1210 	case BCAST_PROTOCOL:
1211 		tipc_link_sync_rcv(node, skb);
1212 		break;
1213 	default:
1214 		break;
1215 	};
1216 }
1217 
1218 /**
1219  * tipc_link_defer_pkt - Add out-of-sequence message to deferred reception queue
1220  *
1221  * Returns increase in queue length (i.e. 0 or 1)
1222  */
1223 u32 tipc_link_defer_pkt(struct sk_buff_head *list, struct sk_buff *skb)
1224 {
1225 	struct sk_buff *skb1;
1226 	u16 seq_no = buf_seqno(skb);
1227 
1228 	/* Empty queue ? */
1229 	if (skb_queue_empty(list)) {
1230 		__skb_queue_tail(list, skb);
1231 		return 1;
1232 	}
1233 
1234 	/* Last ? */
1235 	if (less(buf_seqno(skb_peek_tail(list)), seq_no)) {
1236 		__skb_queue_tail(list, skb);
1237 		return 1;
1238 	}
1239 
1240 	/* Locate insertion point in queue, then insert; discard if duplicate */
1241 	skb_queue_walk(list, skb1) {
1242 		u16 curr_seqno = buf_seqno(skb1);
1243 
1244 		if (seq_no == curr_seqno) {
1245 			kfree_skb(skb);
1246 			return 0;
1247 		}
1248 
1249 		if (less(seq_no, curr_seqno))
1250 			break;
1251 	}
1252 
1253 	__skb_queue_before(list, skb1, skb);
1254 	return 1;
1255 }
1256 
1257 /*
1258  * link_handle_out_of_seq_msg - handle arrival of out-of-sequence packet
1259  */
1260 static void link_handle_out_of_seq_msg(struct tipc_link *l_ptr,
1261 				       struct sk_buff *buf)
1262 {
1263 	u32 seq_no = buf_seqno(buf);
1264 
1265 	if (likely(msg_user(buf_msg(buf)) == LINK_PROTOCOL)) {
1266 		tipc_link_proto_rcv(l_ptr, buf);
1267 		return;
1268 	}
1269 
1270 	/* Record OOS packet arrival */
1271 	l_ptr->silent_intv_cnt = 0;
1272 
1273 	/*
1274 	 * Discard packet if a duplicate; otherwise add it to deferred queue
1275 	 * and notify peer of gap as per protocol specification
1276 	 */
1277 	if (less(seq_no, l_ptr->rcv_nxt)) {
1278 		l_ptr->stats.duplicates++;
1279 		kfree_skb(buf);
1280 		return;
1281 	}
1282 
1283 	if (tipc_link_defer_pkt(&l_ptr->deferdq, buf)) {
1284 		l_ptr->stats.deferred_recv++;
1285 		if ((skb_queue_len(&l_ptr->deferdq) % TIPC_MIN_LINK_WIN) == 1)
1286 			tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, 0, 0, 0);
1287 	} else {
1288 		l_ptr->stats.duplicates++;
1289 	}
1290 }
1291 
1292 /*
1293  * Send protocol message to the other endpoint.
1294  */
1295 void tipc_link_proto_xmit(struct tipc_link *l_ptr, u32 msg_typ, int probe_msg,
1296 			  u32 gap, u32 tolerance, u32 priority)
1297 {
1298 	struct sk_buff *buf = NULL;
1299 	struct tipc_msg *msg = l_ptr->pmsg;
1300 	u32 msg_size = sizeof(l_ptr->proto_msg);
1301 	int r_flag;
1302 	u16 last_rcv;
1303 
1304 	/* Don't send protocol message during link failover */
1305 	if (l_ptr->flags & LINK_FAILINGOVER)
1306 		return;
1307 
1308 	/* Abort non-RESET send if communication with node is prohibited */
1309 	if ((tipc_node_blocked(l_ptr->owner)) && (msg_typ != RESET_MSG))
1310 		return;
1311 
1312 	/* Create protocol message with "out-of-sequence" sequence number */
1313 	msg_set_type(msg, msg_typ);
1314 	msg_set_net_plane(msg, l_ptr->net_plane);
1315 	msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1316 	msg_set_last_bcast(msg, tipc_bclink_get_last_sent(l_ptr->owner->net));
1317 
1318 	if (msg_typ == STATE_MSG) {
1319 		u16 next_sent = l_ptr->snd_nxt;
1320 
1321 		if (!tipc_link_is_up(l_ptr))
1322 			return;
1323 		msg_set_next_sent(msg, next_sent);
1324 		if (!skb_queue_empty(&l_ptr->deferdq)) {
1325 			last_rcv = buf_seqno(skb_peek(&l_ptr->deferdq));
1326 			gap = mod(last_rcv - l_ptr->rcv_nxt);
1327 		}
1328 		msg_set_seq_gap(msg, gap);
1329 		if (gap)
1330 			l_ptr->stats.sent_nacks++;
1331 		msg_set_link_tolerance(msg, tolerance);
1332 		msg_set_linkprio(msg, priority);
1333 		msg_set_max_pkt(msg, l_ptr->mtu);
1334 		msg_set_ack(msg, mod(l_ptr->rcv_nxt - 1));
1335 		msg_set_probe(msg, probe_msg != 0);
1336 		if (probe_msg)
1337 			l_ptr->stats.sent_probes++;
1338 		l_ptr->stats.sent_states++;
1339 	} else {		/* RESET_MSG or ACTIVATE_MSG */
1340 		msg_set_ack(msg, mod(l_ptr->failover_checkpt - 1));
1341 		msg_set_seq_gap(msg, 0);
1342 		msg_set_next_sent(msg, 1);
1343 		msg_set_probe(msg, 0);
1344 		msg_set_link_tolerance(msg, l_ptr->tolerance);
1345 		msg_set_linkprio(msg, l_ptr->priority);
1346 		msg_set_max_pkt(msg, l_ptr->advertised_mtu);
1347 	}
1348 
1349 	r_flag = (l_ptr->owner->working_links > tipc_link_is_up(l_ptr));
1350 	msg_set_redundant_link(msg, r_flag);
1351 	msg_set_linkprio(msg, l_ptr->priority);
1352 	msg_set_size(msg, msg_size);
1353 
1354 	msg_set_seqno(msg, mod(l_ptr->snd_nxt + (0xffff / 2)));
1355 
1356 	buf = tipc_buf_acquire(msg_size);
1357 	if (!buf)
1358 		return;
1359 
1360 	skb_copy_to_linear_data(buf, msg, sizeof(l_ptr->proto_msg));
1361 	buf->priority = TC_PRIO_CONTROL;
1362 	tipc_bearer_send(l_ptr->owner->net, l_ptr->bearer_id, buf,
1363 			 &l_ptr->media_addr);
1364 	l_ptr->rcv_unacked = 0;
1365 	kfree_skb(buf);
1366 }
1367 
1368 /*
1369  * Receive protocol message :
1370  * Note that network plane id propagates through the network, and may
1371  * change at any time. The node with lowest address rules
1372  */
1373 static void tipc_link_proto_rcv(struct tipc_link *l_ptr,
1374 				struct sk_buff *buf)
1375 {
1376 	u32 rec_gap = 0;
1377 	u32 msg_tol;
1378 	struct tipc_msg *msg = buf_msg(buf);
1379 
1380 	if (l_ptr->flags & LINK_FAILINGOVER)
1381 		goto exit;
1382 
1383 	if (l_ptr->net_plane != msg_net_plane(msg))
1384 		if (link_own_addr(l_ptr) > msg_prevnode(msg))
1385 			l_ptr->net_plane = msg_net_plane(msg);
1386 
1387 	switch (msg_type(msg)) {
1388 
1389 	case RESET_MSG:
1390 		if (!link_working_unknown(l_ptr) &&
1391 		    (l_ptr->peer_session != INVALID_SESSION)) {
1392 			if (less_eq(msg_session(msg), l_ptr->peer_session))
1393 				break; /* duplicate or old reset: ignore */
1394 		}
1395 
1396 		if (!msg_redundant_link(msg) && (link_working_working(l_ptr) ||
1397 				link_working_unknown(l_ptr))) {
1398 			/*
1399 			 * peer has lost contact -- don't allow peer's links
1400 			 * to reactivate before we recognize loss & clean up
1401 			 */
1402 			l_ptr->owner->action_flags |= TIPC_WAIT_OWN_LINKS_DOWN;
1403 		}
1404 
1405 		link_state_event(l_ptr, RESET_MSG);
1406 
1407 		/* fall thru' */
1408 	case ACTIVATE_MSG:
1409 		/* Update link settings according other endpoint's values */
1410 		strcpy((strrchr(l_ptr->name, ':') + 1), (char *)msg_data(msg));
1411 
1412 		msg_tol = msg_link_tolerance(msg);
1413 		if (msg_tol > l_ptr->tolerance)
1414 			link_set_supervision_props(l_ptr, msg_tol);
1415 
1416 		if (msg_linkprio(msg) > l_ptr->priority)
1417 			l_ptr->priority = msg_linkprio(msg);
1418 
1419 		if (l_ptr->mtu > msg_max_pkt(msg))
1420 			l_ptr->mtu = msg_max_pkt(msg);
1421 
1422 		/* Synchronize broadcast link info, if not done previously */
1423 		if (!tipc_node_is_up(l_ptr->owner)) {
1424 			l_ptr->owner->bclink.last_sent =
1425 				l_ptr->owner->bclink.last_in =
1426 				msg_last_bcast(msg);
1427 			l_ptr->owner->bclink.oos_state = 0;
1428 		}
1429 
1430 		l_ptr->peer_session = msg_session(msg);
1431 		l_ptr->peer_bearer_id = msg_bearer_id(msg);
1432 
1433 		if (msg_type(msg) == ACTIVATE_MSG)
1434 			link_state_event(l_ptr, ACTIVATE_MSG);
1435 		break;
1436 	case STATE_MSG:
1437 
1438 		msg_tol = msg_link_tolerance(msg);
1439 		if (msg_tol)
1440 			link_set_supervision_props(l_ptr, msg_tol);
1441 
1442 		if (msg_linkprio(msg) &&
1443 		    (msg_linkprio(msg) != l_ptr->priority)) {
1444 			pr_debug("%s<%s>, priority change %u->%u\n",
1445 				 link_rst_msg, l_ptr->name,
1446 				 l_ptr->priority, msg_linkprio(msg));
1447 			l_ptr->priority = msg_linkprio(msg);
1448 			tipc_link_reset(l_ptr); /* Enforce change to take effect */
1449 			break;
1450 		}
1451 
1452 		/* Record reception; force mismatch at next timeout: */
1453 		l_ptr->silent_intv_cnt = 0;
1454 
1455 		link_state_event(l_ptr, TRAFFIC_MSG_EVT);
1456 		l_ptr->stats.recv_states++;
1457 		if (link_reset_unknown(l_ptr))
1458 			break;
1459 
1460 		if (less_eq(l_ptr->rcv_nxt, msg_next_sent(msg)))
1461 			rec_gap = mod(msg_next_sent(msg) - l_ptr->rcv_nxt);
1462 
1463 		if (msg_probe(msg))
1464 			l_ptr->stats.recv_probes++;
1465 
1466 		/* Protocol message before retransmits, reduce loss risk */
1467 		if (l_ptr->owner->bclink.recv_permitted)
1468 			tipc_bclink_update_link_state(l_ptr->owner,
1469 						      msg_last_bcast(msg));
1470 
1471 		if (rec_gap || (msg_probe(msg))) {
1472 			tipc_link_proto_xmit(l_ptr, STATE_MSG, 0,
1473 					     rec_gap, 0, 0);
1474 		}
1475 		if (msg_seq_gap(msg)) {
1476 			l_ptr->stats.recv_nacks++;
1477 			tipc_link_retransmit(l_ptr, skb_peek(&l_ptr->transmq),
1478 					     msg_seq_gap(msg));
1479 		}
1480 		break;
1481 	}
1482 exit:
1483 	kfree_skb(buf);
1484 }
1485 
1486 
1487 /* tipc_link_tunnel_xmit(): Tunnel one packet via a link belonging to
1488  * a different bearer. Owner node is locked.
1489  */
1490 static void tipc_link_tunnel_xmit(struct tipc_link *l_ptr,
1491 				  struct tipc_msg *tunnel_hdr,
1492 				  struct tipc_msg *msg,
1493 				  u32 selector)
1494 {
1495 	struct tipc_link *tunnel;
1496 	struct sk_buff *skb;
1497 	u32 length = msg_size(msg);
1498 
1499 	tunnel = l_ptr->owner->active_links[selector & 1];
1500 	if (!tipc_link_is_up(tunnel)) {
1501 		pr_warn("%stunnel link no longer available\n", link_co_err);
1502 		return;
1503 	}
1504 	msg_set_size(tunnel_hdr, length + INT_H_SIZE);
1505 	skb = tipc_buf_acquire(length + INT_H_SIZE);
1506 	if (!skb) {
1507 		pr_warn("%sunable to send tunnel msg\n", link_co_err);
1508 		return;
1509 	}
1510 	skb_copy_to_linear_data(skb, tunnel_hdr, INT_H_SIZE);
1511 	skb_copy_to_linear_data_offset(skb, INT_H_SIZE, msg, length);
1512 	__tipc_link_xmit_skb(tunnel, skb);
1513 }
1514 
1515 
1516 /* tipc_link_failover_send_queue(): A link has gone down, but a second
1517  * link is still active. We can do failover. Tunnel the failing link's
1518  * whole send queue via the remaining link. This way, we don't lose
1519  * any packets, and sequence order is preserved for subsequent traffic
1520  * sent over the remaining link. Owner node is locked.
1521  */
1522 void tipc_link_failover_send_queue(struct tipc_link *l_ptr)
1523 {
1524 	int msgcount;
1525 	struct tipc_link *tunnel = l_ptr->owner->active_links[0];
1526 	struct tipc_msg tunnel_hdr;
1527 	struct sk_buff *skb;
1528 	int split_bundles;
1529 
1530 	if (!tunnel)
1531 		return;
1532 
1533 	tipc_msg_init(link_own_addr(l_ptr), &tunnel_hdr, TUNNEL_PROTOCOL,
1534 		      FAILOVER_MSG, INT_H_SIZE, l_ptr->addr);
1535 
1536 	skb_queue_walk(&l_ptr->backlogq, skb) {
1537 		msg_set_seqno(buf_msg(skb), l_ptr->snd_nxt);
1538 		l_ptr->snd_nxt = mod(l_ptr->snd_nxt + 1);
1539 	}
1540 	skb_queue_splice_tail_init(&l_ptr->backlogq, &l_ptr->transmq);
1541 	tipc_link_purge_backlog(l_ptr);
1542 	msgcount = skb_queue_len(&l_ptr->transmq);
1543 	msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
1544 	msg_set_msgcnt(&tunnel_hdr, msgcount);
1545 
1546 	if (skb_queue_empty(&l_ptr->transmq)) {
1547 		skb = tipc_buf_acquire(INT_H_SIZE);
1548 		if (skb) {
1549 			skb_copy_to_linear_data(skb, &tunnel_hdr, INT_H_SIZE);
1550 			msg_set_size(&tunnel_hdr, INT_H_SIZE);
1551 			__tipc_link_xmit_skb(tunnel, skb);
1552 		} else {
1553 			pr_warn("%sunable to send changeover msg\n",
1554 				link_co_err);
1555 		}
1556 		return;
1557 	}
1558 
1559 	split_bundles = (l_ptr->owner->active_links[0] !=
1560 			 l_ptr->owner->active_links[1]);
1561 
1562 	skb_queue_walk(&l_ptr->transmq, skb) {
1563 		struct tipc_msg *msg = buf_msg(skb);
1564 
1565 		if ((msg_user(msg) == MSG_BUNDLER) && split_bundles) {
1566 			struct tipc_msg *m = msg_get_wrapped(msg);
1567 			unchar *pos = (unchar *)m;
1568 
1569 			msgcount = msg_msgcnt(msg);
1570 			while (msgcount--) {
1571 				msg_set_seqno(m, msg_seqno(msg));
1572 				tipc_link_tunnel_xmit(l_ptr, &tunnel_hdr, m,
1573 						      msg_link_selector(m));
1574 				pos += align(msg_size(m));
1575 				m = (struct tipc_msg *)pos;
1576 			}
1577 		} else {
1578 			tipc_link_tunnel_xmit(l_ptr, &tunnel_hdr, msg,
1579 					      msg_link_selector(msg));
1580 		}
1581 	}
1582 }
1583 
1584 /* tipc_link_dup_queue_xmit(): A second link has become active. Tunnel a
1585  * duplicate of the first link's send queue via the new link. This way, we
1586  * are guaranteed that currently queued packets from a socket are delivered
1587  * before future traffic from the same socket, even if this is using the
1588  * new link. The last arriving copy of each duplicate packet is dropped at
1589  * the receiving end by the regular protocol check, so packet cardinality
1590  * and sequence order is preserved per sender/receiver socket pair.
1591  * Owner node is locked.
1592  */
1593 void tipc_link_dup_queue_xmit(struct tipc_link *link,
1594 			      struct tipc_link *tnl)
1595 {
1596 	struct sk_buff *skb;
1597 	struct tipc_msg tnl_hdr;
1598 	struct sk_buff_head *queue = &link->transmq;
1599 	int mcnt;
1600 	u16 seqno;
1601 
1602 	tipc_msg_init(link_own_addr(link), &tnl_hdr, TUNNEL_PROTOCOL,
1603 		      SYNCH_MSG, INT_H_SIZE, link->addr);
1604 	mcnt = skb_queue_len(&link->transmq) + skb_queue_len(&link->backlogq);
1605 	msg_set_msgcnt(&tnl_hdr, mcnt);
1606 	msg_set_bearer_id(&tnl_hdr, link->peer_bearer_id);
1607 
1608 tunnel_queue:
1609 	skb_queue_walk(queue, skb) {
1610 		struct sk_buff *outskb;
1611 		struct tipc_msg *msg = buf_msg(skb);
1612 		u32 len = msg_size(msg);
1613 
1614 		msg_set_ack(msg, mod(link->rcv_nxt - 1));
1615 		msg_set_bcast_ack(msg, link->owner->bclink.last_in);
1616 		msg_set_size(&tnl_hdr, len + INT_H_SIZE);
1617 		outskb = tipc_buf_acquire(len + INT_H_SIZE);
1618 		if (outskb == NULL) {
1619 			pr_warn("%sunable to send duplicate msg\n",
1620 				link_co_err);
1621 			return;
1622 		}
1623 		skb_copy_to_linear_data(outskb, &tnl_hdr, INT_H_SIZE);
1624 		skb_copy_to_linear_data_offset(outskb, INT_H_SIZE,
1625 					       skb->data, len);
1626 		__tipc_link_xmit_skb(tnl, outskb);
1627 		if (!tipc_link_is_up(link))
1628 			return;
1629 	}
1630 	if (queue == &link->backlogq)
1631 		return;
1632 	seqno = link->snd_nxt;
1633 	skb_queue_walk(&link->backlogq, skb) {
1634 		msg_set_seqno(buf_msg(skb), seqno);
1635 		seqno = mod(seqno + 1);
1636 	}
1637 	queue = &link->backlogq;
1638 	goto tunnel_queue;
1639 }
1640 
1641 /*  tipc_link_failover_rcv(): Receive a tunnelled FAILOVER_MSG packet
1642  *  Owner node is locked.
1643  */
1644 static bool tipc_link_failover_rcv(struct tipc_link *link,
1645 				   struct sk_buff **skb)
1646 {
1647 	struct tipc_msg *msg = buf_msg(*skb);
1648 	struct sk_buff *iskb = NULL;
1649 	struct tipc_link *pl = NULL;
1650 	int bearer_id = msg_bearer_id(msg);
1651 	int pos = 0;
1652 
1653 	if (msg_type(msg) != FAILOVER_MSG) {
1654 		pr_warn("%sunknown tunnel pkt received\n", link_co_err);
1655 		goto exit;
1656 	}
1657 	if (bearer_id >= MAX_BEARERS)
1658 		goto exit;
1659 
1660 	if (bearer_id == link->bearer_id)
1661 		goto exit;
1662 
1663 	pl = link->owner->links[bearer_id];
1664 	if (pl && tipc_link_is_up(pl))
1665 		tipc_link_reset(pl);
1666 
1667 	if (link->failover_pkts == FIRST_FAILOVER)
1668 		link->failover_pkts = msg_msgcnt(msg);
1669 
1670 	/* Should we expect an inner packet? */
1671 	if (!link->failover_pkts)
1672 		goto exit;
1673 
1674 	if (!tipc_msg_extract(*skb, &iskb, &pos)) {
1675 		pr_warn("%sno inner failover pkt\n", link_co_err);
1676 		*skb = NULL;
1677 		goto exit;
1678 	}
1679 	link->failover_pkts--;
1680 	*skb = NULL;
1681 
1682 	/* Was this packet already delivered? */
1683 	if (less(buf_seqno(iskb), link->failover_checkpt)) {
1684 		kfree_skb(iskb);
1685 		iskb = NULL;
1686 		goto exit;
1687 	}
1688 	if (msg_user(buf_msg(iskb)) == MSG_FRAGMENTER) {
1689 		link->stats.recv_fragments++;
1690 		tipc_buf_append(&link->failover_skb, &iskb);
1691 	}
1692 exit:
1693 	if (!link->failover_pkts && pl)
1694 		pl->flags &= ~LINK_FAILINGOVER;
1695 	kfree_skb(*skb);
1696 	*skb = iskb;
1697 	return *skb;
1698 }
1699 
1700 static void link_set_supervision_props(struct tipc_link *l_ptr, u32 tol)
1701 {
1702 	unsigned long intv = ((tol / 4) > 500) ? 500 : tol / 4;
1703 
1704 	if ((tol < TIPC_MIN_LINK_TOL) || (tol > TIPC_MAX_LINK_TOL))
1705 		return;
1706 
1707 	l_ptr->tolerance = tol;
1708 	l_ptr->keepalive_intv = msecs_to_jiffies(intv);
1709 	l_ptr->abort_limit = tol / (jiffies_to_msecs(l_ptr->keepalive_intv));
1710 }
1711 
1712 void tipc_link_set_queue_limits(struct tipc_link *l, u32 win)
1713 {
1714 	int max_bulk = TIPC_MAX_PUBLICATIONS / (l->mtu / ITEM_SIZE);
1715 
1716 	l->window = win;
1717 	l->backlog[TIPC_LOW_IMPORTANCE].limit      = win / 2;
1718 	l->backlog[TIPC_MEDIUM_IMPORTANCE].limit   = win;
1719 	l->backlog[TIPC_HIGH_IMPORTANCE].limit     = win / 2 * 3;
1720 	l->backlog[TIPC_CRITICAL_IMPORTANCE].limit = win * 2;
1721 	l->backlog[TIPC_SYSTEM_IMPORTANCE].limit   = max_bulk;
1722 }
1723 
1724 /* tipc_link_find_owner - locate owner node of link by link's name
1725  * @net: the applicable net namespace
1726  * @name: pointer to link name string
1727  * @bearer_id: pointer to index in 'node->links' array where the link was found.
1728  *
1729  * Returns pointer to node owning the link, or 0 if no matching link is found.
1730  */
1731 static struct tipc_node *tipc_link_find_owner(struct net *net,
1732 					      const char *link_name,
1733 					      unsigned int *bearer_id)
1734 {
1735 	struct tipc_net *tn = net_generic(net, tipc_net_id);
1736 	struct tipc_link *l_ptr;
1737 	struct tipc_node *n_ptr;
1738 	struct tipc_node *found_node = NULL;
1739 	int i;
1740 
1741 	*bearer_id = 0;
1742 	rcu_read_lock();
1743 	list_for_each_entry_rcu(n_ptr, &tn->node_list, list) {
1744 		tipc_node_lock(n_ptr);
1745 		for (i = 0; i < MAX_BEARERS; i++) {
1746 			l_ptr = n_ptr->links[i];
1747 			if (l_ptr && !strcmp(l_ptr->name, link_name)) {
1748 				*bearer_id = i;
1749 				found_node = n_ptr;
1750 				break;
1751 			}
1752 		}
1753 		tipc_node_unlock(n_ptr);
1754 		if (found_node)
1755 			break;
1756 	}
1757 	rcu_read_unlock();
1758 
1759 	return found_node;
1760 }
1761 
1762 /**
1763  * link_reset_statistics - reset link statistics
1764  * @l_ptr: pointer to link
1765  */
1766 static void link_reset_statistics(struct tipc_link *l_ptr)
1767 {
1768 	memset(&l_ptr->stats, 0, sizeof(l_ptr->stats));
1769 	l_ptr->stats.sent_info = l_ptr->snd_nxt;
1770 	l_ptr->stats.recv_info = l_ptr->rcv_nxt;
1771 }
1772 
1773 static void link_print(struct tipc_link *l_ptr, const char *str)
1774 {
1775 	struct tipc_net *tn = net_generic(l_ptr->owner->net, tipc_net_id);
1776 	struct tipc_bearer *b_ptr;
1777 
1778 	rcu_read_lock();
1779 	b_ptr = rcu_dereference_rtnl(tn->bearer_list[l_ptr->bearer_id]);
1780 	if (b_ptr)
1781 		pr_info("%s Link %x<%s>:", str, l_ptr->addr, b_ptr->name);
1782 	rcu_read_unlock();
1783 
1784 	if (link_working_unknown(l_ptr))
1785 		pr_cont(":WU\n");
1786 	else if (link_reset_reset(l_ptr))
1787 		pr_cont(":RR\n");
1788 	else if (link_reset_unknown(l_ptr))
1789 		pr_cont(":RU\n");
1790 	else if (link_working_working(l_ptr))
1791 		pr_cont(":WW\n");
1792 	else
1793 		pr_cont("\n");
1794 }
1795 
1796 /* Parse and validate nested (link) properties valid for media, bearer and link
1797  */
1798 int tipc_nl_parse_link_prop(struct nlattr *prop, struct nlattr *props[])
1799 {
1800 	int err;
1801 
1802 	err = nla_parse_nested(props, TIPC_NLA_PROP_MAX, prop,
1803 			       tipc_nl_prop_policy);
1804 	if (err)
1805 		return err;
1806 
1807 	if (props[TIPC_NLA_PROP_PRIO]) {
1808 		u32 prio;
1809 
1810 		prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
1811 		if (prio > TIPC_MAX_LINK_PRI)
1812 			return -EINVAL;
1813 	}
1814 
1815 	if (props[TIPC_NLA_PROP_TOL]) {
1816 		u32 tol;
1817 
1818 		tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
1819 		if ((tol < TIPC_MIN_LINK_TOL) || (tol > TIPC_MAX_LINK_TOL))
1820 			return -EINVAL;
1821 	}
1822 
1823 	if (props[TIPC_NLA_PROP_WIN]) {
1824 		u32 win;
1825 
1826 		win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
1827 		if ((win < TIPC_MIN_LINK_WIN) || (win > TIPC_MAX_LINK_WIN))
1828 			return -EINVAL;
1829 	}
1830 
1831 	return 0;
1832 }
1833 
1834 int tipc_nl_link_set(struct sk_buff *skb, struct genl_info *info)
1835 {
1836 	int err;
1837 	int res = 0;
1838 	int bearer_id;
1839 	char *name;
1840 	struct tipc_link *link;
1841 	struct tipc_node *node;
1842 	struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
1843 	struct net *net = sock_net(skb->sk);
1844 
1845 	if (!info->attrs[TIPC_NLA_LINK])
1846 		return -EINVAL;
1847 
1848 	err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
1849 			       info->attrs[TIPC_NLA_LINK],
1850 			       tipc_nl_link_policy);
1851 	if (err)
1852 		return err;
1853 
1854 	if (!attrs[TIPC_NLA_LINK_NAME])
1855 		return -EINVAL;
1856 
1857 	name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
1858 
1859 	if (strcmp(name, tipc_bclink_name) == 0)
1860 		return tipc_nl_bc_link_set(net, attrs);
1861 
1862 	node = tipc_link_find_owner(net, name, &bearer_id);
1863 	if (!node)
1864 		return -EINVAL;
1865 
1866 	tipc_node_lock(node);
1867 
1868 	link = node->links[bearer_id];
1869 	if (!link) {
1870 		res = -EINVAL;
1871 		goto out;
1872 	}
1873 
1874 	if (attrs[TIPC_NLA_LINK_PROP]) {
1875 		struct nlattr *props[TIPC_NLA_PROP_MAX + 1];
1876 
1877 		err = tipc_nl_parse_link_prop(attrs[TIPC_NLA_LINK_PROP],
1878 					      props);
1879 		if (err) {
1880 			res = err;
1881 			goto out;
1882 		}
1883 
1884 		if (props[TIPC_NLA_PROP_TOL]) {
1885 			u32 tol;
1886 
1887 			tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
1888 			link_set_supervision_props(link, tol);
1889 			tipc_link_proto_xmit(link, STATE_MSG, 0, 0, tol, 0);
1890 		}
1891 		if (props[TIPC_NLA_PROP_PRIO]) {
1892 			u32 prio;
1893 
1894 			prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
1895 			link->priority = prio;
1896 			tipc_link_proto_xmit(link, STATE_MSG, 0, 0, 0, prio);
1897 		}
1898 		if (props[TIPC_NLA_PROP_WIN]) {
1899 			u32 win;
1900 
1901 			win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
1902 			tipc_link_set_queue_limits(link, win);
1903 		}
1904 	}
1905 
1906 out:
1907 	tipc_node_unlock(node);
1908 
1909 	return res;
1910 }
1911 
1912 static int __tipc_nl_add_stats(struct sk_buff *skb, struct tipc_stats *s)
1913 {
1914 	int i;
1915 	struct nlattr *stats;
1916 
1917 	struct nla_map {
1918 		u32 key;
1919 		u32 val;
1920 	};
1921 
1922 	struct nla_map map[] = {
1923 		{TIPC_NLA_STATS_RX_INFO, s->recv_info},
1924 		{TIPC_NLA_STATS_RX_FRAGMENTS, s->recv_fragments},
1925 		{TIPC_NLA_STATS_RX_FRAGMENTED, s->recv_fragmented},
1926 		{TIPC_NLA_STATS_RX_BUNDLES, s->recv_bundles},
1927 		{TIPC_NLA_STATS_RX_BUNDLED, s->recv_bundled},
1928 		{TIPC_NLA_STATS_TX_INFO, s->sent_info},
1929 		{TIPC_NLA_STATS_TX_FRAGMENTS, s->sent_fragments},
1930 		{TIPC_NLA_STATS_TX_FRAGMENTED, s->sent_fragmented},
1931 		{TIPC_NLA_STATS_TX_BUNDLES, s->sent_bundles},
1932 		{TIPC_NLA_STATS_TX_BUNDLED, s->sent_bundled},
1933 		{TIPC_NLA_STATS_MSG_PROF_TOT, (s->msg_length_counts) ?
1934 			s->msg_length_counts : 1},
1935 		{TIPC_NLA_STATS_MSG_LEN_CNT, s->msg_length_counts},
1936 		{TIPC_NLA_STATS_MSG_LEN_TOT, s->msg_lengths_total},
1937 		{TIPC_NLA_STATS_MSG_LEN_P0, s->msg_length_profile[0]},
1938 		{TIPC_NLA_STATS_MSG_LEN_P1, s->msg_length_profile[1]},
1939 		{TIPC_NLA_STATS_MSG_LEN_P2, s->msg_length_profile[2]},
1940 		{TIPC_NLA_STATS_MSG_LEN_P3, s->msg_length_profile[3]},
1941 		{TIPC_NLA_STATS_MSG_LEN_P4, s->msg_length_profile[4]},
1942 		{TIPC_NLA_STATS_MSG_LEN_P5, s->msg_length_profile[5]},
1943 		{TIPC_NLA_STATS_MSG_LEN_P6, s->msg_length_profile[6]},
1944 		{TIPC_NLA_STATS_RX_STATES, s->recv_states},
1945 		{TIPC_NLA_STATS_RX_PROBES, s->recv_probes},
1946 		{TIPC_NLA_STATS_RX_NACKS, s->recv_nacks},
1947 		{TIPC_NLA_STATS_RX_DEFERRED, s->deferred_recv},
1948 		{TIPC_NLA_STATS_TX_STATES, s->sent_states},
1949 		{TIPC_NLA_STATS_TX_PROBES, s->sent_probes},
1950 		{TIPC_NLA_STATS_TX_NACKS, s->sent_nacks},
1951 		{TIPC_NLA_STATS_TX_ACKS, s->sent_acks},
1952 		{TIPC_NLA_STATS_RETRANSMITTED, s->retransmitted},
1953 		{TIPC_NLA_STATS_DUPLICATES, s->duplicates},
1954 		{TIPC_NLA_STATS_LINK_CONGS, s->link_congs},
1955 		{TIPC_NLA_STATS_MAX_QUEUE, s->max_queue_sz},
1956 		{TIPC_NLA_STATS_AVG_QUEUE, s->queue_sz_counts ?
1957 			(s->accu_queue_sz / s->queue_sz_counts) : 0}
1958 	};
1959 
1960 	stats = nla_nest_start(skb, TIPC_NLA_LINK_STATS);
1961 	if (!stats)
1962 		return -EMSGSIZE;
1963 
1964 	for (i = 0; i <  ARRAY_SIZE(map); i++)
1965 		if (nla_put_u32(skb, map[i].key, map[i].val))
1966 			goto msg_full;
1967 
1968 	nla_nest_end(skb, stats);
1969 
1970 	return 0;
1971 msg_full:
1972 	nla_nest_cancel(skb, stats);
1973 
1974 	return -EMSGSIZE;
1975 }
1976 
1977 /* Caller should hold appropriate locks to protect the link */
1978 static int __tipc_nl_add_link(struct net *net, struct tipc_nl_msg *msg,
1979 			      struct tipc_link *link, int nlflags)
1980 {
1981 	int err;
1982 	void *hdr;
1983 	struct nlattr *attrs;
1984 	struct nlattr *prop;
1985 	struct tipc_net *tn = net_generic(net, tipc_net_id);
1986 
1987 	hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
1988 			  nlflags, TIPC_NL_LINK_GET);
1989 	if (!hdr)
1990 		return -EMSGSIZE;
1991 
1992 	attrs = nla_nest_start(msg->skb, TIPC_NLA_LINK);
1993 	if (!attrs)
1994 		goto msg_full;
1995 
1996 	if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, link->name))
1997 		goto attr_msg_full;
1998 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_DEST,
1999 			tipc_cluster_mask(tn->own_addr)))
2000 		goto attr_msg_full;
2001 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_MTU, link->mtu))
2002 		goto attr_msg_full;
2003 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, link->rcv_nxt))
2004 		goto attr_msg_full;
2005 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, link->snd_nxt))
2006 		goto attr_msg_full;
2007 
2008 	if (tipc_link_is_up(link))
2009 		if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
2010 			goto attr_msg_full;
2011 	if (tipc_link_is_active(link))
2012 		if (nla_put_flag(msg->skb, TIPC_NLA_LINK_ACTIVE))
2013 			goto attr_msg_full;
2014 
2015 	prop = nla_nest_start(msg->skb, TIPC_NLA_LINK_PROP);
2016 	if (!prop)
2017 		goto attr_msg_full;
2018 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
2019 		goto prop_msg_full;
2020 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_TOL, link->tolerance))
2021 		goto prop_msg_full;
2022 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN,
2023 			link->window))
2024 		goto prop_msg_full;
2025 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
2026 		goto prop_msg_full;
2027 	nla_nest_end(msg->skb, prop);
2028 
2029 	err = __tipc_nl_add_stats(msg->skb, &link->stats);
2030 	if (err)
2031 		goto attr_msg_full;
2032 
2033 	nla_nest_end(msg->skb, attrs);
2034 	genlmsg_end(msg->skb, hdr);
2035 
2036 	return 0;
2037 
2038 prop_msg_full:
2039 	nla_nest_cancel(msg->skb, prop);
2040 attr_msg_full:
2041 	nla_nest_cancel(msg->skb, attrs);
2042 msg_full:
2043 	genlmsg_cancel(msg->skb, hdr);
2044 
2045 	return -EMSGSIZE;
2046 }
2047 
2048 /* Caller should hold node lock  */
2049 static int __tipc_nl_add_node_links(struct net *net, struct tipc_nl_msg *msg,
2050 				    struct tipc_node *node, u32 *prev_link)
2051 {
2052 	u32 i;
2053 	int err;
2054 
2055 	for (i = *prev_link; i < MAX_BEARERS; i++) {
2056 		*prev_link = i;
2057 
2058 		if (!node->links[i])
2059 			continue;
2060 
2061 		err = __tipc_nl_add_link(net, msg, node->links[i], NLM_F_MULTI);
2062 		if (err)
2063 			return err;
2064 	}
2065 	*prev_link = 0;
2066 
2067 	return 0;
2068 }
2069 
2070 int tipc_nl_link_dump(struct sk_buff *skb, struct netlink_callback *cb)
2071 {
2072 	struct net *net = sock_net(skb->sk);
2073 	struct tipc_net *tn = net_generic(net, tipc_net_id);
2074 	struct tipc_node *node;
2075 	struct tipc_nl_msg msg;
2076 	u32 prev_node = cb->args[0];
2077 	u32 prev_link = cb->args[1];
2078 	int done = cb->args[2];
2079 	int err;
2080 
2081 	if (done)
2082 		return 0;
2083 
2084 	msg.skb = skb;
2085 	msg.portid = NETLINK_CB(cb->skb).portid;
2086 	msg.seq = cb->nlh->nlmsg_seq;
2087 
2088 	rcu_read_lock();
2089 	if (prev_node) {
2090 		node = tipc_node_find(net, prev_node);
2091 		if (!node) {
2092 			/* We never set seq or call nl_dump_check_consistent()
2093 			 * this means that setting prev_seq here will cause the
2094 			 * consistence check to fail in the netlink callback
2095 			 * handler. Resulting in the last NLMSG_DONE message
2096 			 * having the NLM_F_DUMP_INTR flag set.
2097 			 */
2098 			cb->prev_seq = 1;
2099 			goto out;
2100 		}
2101 		tipc_node_put(node);
2102 
2103 		list_for_each_entry_continue_rcu(node, &tn->node_list,
2104 						 list) {
2105 			tipc_node_lock(node);
2106 			err = __tipc_nl_add_node_links(net, &msg, node,
2107 						       &prev_link);
2108 			tipc_node_unlock(node);
2109 			if (err)
2110 				goto out;
2111 
2112 			prev_node = node->addr;
2113 		}
2114 	} else {
2115 		err = tipc_nl_add_bc_link(net, &msg);
2116 		if (err)
2117 			goto out;
2118 
2119 		list_for_each_entry_rcu(node, &tn->node_list, list) {
2120 			tipc_node_lock(node);
2121 			err = __tipc_nl_add_node_links(net, &msg, node,
2122 						       &prev_link);
2123 			tipc_node_unlock(node);
2124 			if (err)
2125 				goto out;
2126 
2127 			prev_node = node->addr;
2128 		}
2129 	}
2130 	done = 1;
2131 out:
2132 	rcu_read_unlock();
2133 
2134 	cb->args[0] = prev_node;
2135 	cb->args[1] = prev_link;
2136 	cb->args[2] = done;
2137 
2138 	return skb->len;
2139 }
2140 
2141 int tipc_nl_link_get(struct sk_buff *skb, struct genl_info *info)
2142 {
2143 	struct net *net = genl_info_net(info);
2144 	struct tipc_nl_msg msg;
2145 	char *name;
2146 	int err;
2147 
2148 	msg.portid = info->snd_portid;
2149 	msg.seq = info->snd_seq;
2150 
2151 	if (!info->attrs[TIPC_NLA_LINK_NAME])
2152 		return -EINVAL;
2153 	name = nla_data(info->attrs[TIPC_NLA_LINK_NAME]);
2154 
2155 	msg.skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
2156 	if (!msg.skb)
2157 		return -ENOMEM;
2158 
2159 	if (strcmp(name, tipc_bclink_name) == 0) {
2160 		err = tipc_nl_add_bc_link(net, &msg);
2161 		if (err) {
2162 			nlmsg_free(msg.skb);
2163 			return err;
2164 		}
2165 	} else {
2166 		int bearer_id;
2167 		struct tipc_node *node;
2168 		struct tipc_link *link;
2169 
2170 		node = tipc_link_find_owner(net, name, &bearer_id);
2171 		if (!node)
2172 			return -EINVAL;
2173 
2174 		tipc_node_lock(node);
2175 		link = node->links[bearer_id];
2176 		if (!link) {
2177 			tipc_node_unlock(node);
2178 			nlmsg_free(msg.skb);
2179 			return -EINVAL;
2180 		}
2181 
2182 		err = __tipc_nl_add_link(net, &msg, link, 0);
2183 		tipc_node_unlock(node);
2184 		if (err) {
2185 			nlmsg_free(msg.skb);
2186 			return err;
2187 		}
2188 	}
2189 
2190 	return genlmsg_reply(msg.skb, info);
2191 }
2192 
2193 int tipc_nl_link_reset_stats(struct sk_buff *skb, struct genl_info *info)
2194 {
2195 	int err;
2196 	char *link_name;
2197 	unsigned int bearer_id;
2198 	struct tipc_link *link;
2199 	struct tipc_node *node;
2200 	struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
2201 	struct net *net = sock_net(skb->sk);
2202 
2203 	if (!info->attrs[TIPC_NLA_LINK])
2204 		return -EINVAL;
2205 
2206 	err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
2207 			       info->attrs[TIPC_NLA_LINK],
2208 			       tipc_nl_link_policy);
2209 	if (err)
2210 		return err;
2211 
2212 	if (!attrs[TIPC_NLA_LINK_NAME])
2213 		return -EINVAL;
2214 
2215 	link_name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
2216 
2217 	if (strcmp(link_name, tipc_bclink_name) == 0) {
2218 		err = tipc_bclink_reset_stats(net);
2219 		if (err)
2220 			return err;
2221 		return 0;
2222 	}
2223 
2224 	node = tipc_link_find_owner(net, link_name, &bearer_id);
2225 	if (!node)
2226 		return -EINVAL;
2227 
2228 	tipc_node_lock(node);
2229 
2230 	link = node->links[bearer_id];
2231 	if (!link) {
2232 		tipc_node_unlock(node);
2233 		return -EINVAL;
2234 	}
2235 
2236 	link_reset_statistics(link);
2237 
2238 	tipc_node_unlock(node);
2239 
2240 	return 0;
2241 }
2242