xref: /linux/net/tipc/link.c (revision 3f2fb9a834cb1fcddbae22deca7fde136944dc89)
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 struct tipc_stats {
49 	u32 sent_info;		/* used in counting # sent packets */
50 	u32 recv_info;		/* used in counting # recv'd packets */
51 	u32 sent_states;
52 	u32 recv_states;
53 	u32 sent_probes;
54 	u32 recv_probes;
55 	u32 sent_nacks;
56 	u32 recv_nacks;
57 	u32 sent_acks;
58 	u32 sent_bundled;
59 	u32 sent_bundles;
60 	u32 recv_bundled;
61 	u32 recv_bundles;
62 	u32 retransmitted;
63 	u32 sent_fragmented;
64 	u32 sent_fragments;
65 	u32 recv_fragmented;
66 	u32 recv_fragments;
67 	u32 link_congs;		/* # port sends blocked by congestion */
68 	u32 deferred_recv;
69 	u32 duplicates;
70 	u32 max_queue_sz;	/* send queue size high water mark */
71 	u32 accu_queue_sz;	/* used for send queue size profiling */
72 	u32 queue_sz_counts;	/* used for send queue size profiling */
73 	u32 msg_length_counts;	/* used for message length profiling */
74 	u32 msg_lengths_total;	/* used for message length profiling */
75 	u32 msg_length_profile[7]; /* used for msg. length profiling */
76 };
77 
78 /**
79  * struct tipc_link - TIPC link data structure
80  * @addr: network address of link's peer node
81  * @name: link name character string
82  * @media_addr: media address to use when sending messages over link
83  * @timer: link timer
84  * @net: pointer to namespace struct
85  * @refcnt: reference counter for permanent references (owner node & timer)
86  * @peer_session: link session # being used by peer end of link
87  * @peer_bearer_id: bearer id used by link's peer endpoint
88  * @bearer_id: local bearer id used by link
89  * @tolerance: minimum link continuity loss needed to reset link [in ms]
90  * @keepalive_intv: link keepalive timer interval
91  * @abort_limit: # of unacknowledged continuity probes needed to reset link
92  * @state: current state of link FSM
93  * @peer_caps: bitmap describing capabilities of peer node
94  * @silent_intv_cnt: # of timer intervals without any reception from peer
95  * @proto_msg: template for control messages generated by link
96  * @pmsg: convenience pointer to "proto_msg" field
97  * @priority: current link priority
98  * @net_plane: current link network plane ('A' through 'H')
99  * @backlog_limit: backlog queue congestion thresholds (indexed by importance)
100  * @exp_msg_count: # of tunnelled messages expected during link changeover
101  * @reset_rcv_checkpt: seq # of last acknowledged message at time of link reset
102  * @mtu: current maximum packet size for this link
103  * @advertised_mtu: advertised own mtu when link is being established
104  * @transmitq: queue for sent, non-acked messages
105  * @backlogq: queue for messages waiting to be sent
106  * @snt_nxt: next sequence number to use for outbound messages
107  * @last_retransmitted: sequence number of most recently retransmitted message
108  * @stale_count: # of identical retransmit requests made by peer
109  * @ackers: # of peers that needs to ack each packet before it can be released
110  * @acked: # last packet acked by a certain peer. Used for broadcast.
111  * @rcv_nxt: next sequence number to expect for inbound messages
112  * @deferred_queue: deferred queue saved OOS b'cast message received from node
113  * @unacked_window: # of inbound messages rx'd without ack'ing back to peer
114  * @inputq: buffer queue for messages to be delivered upwards
115  * @namedq: buffer queue for name table messages to be delivered upwards
116  * @next_out: ptr to first unsent outbound message in queue
117  * @wakeupq: linked list of wakeup msgs waiting for link congestion to abate
118  * @long_msg_seq_no: next identifier to use for outbound fragmented messages
119  * @reasm_buf: head of partially reassembled inbound message fragments
120  * @bc_rcvr: marks that this is a broadcast receiver link
121  * @stats: collects statistics regarding link activity
122  */
123 struct tipc_link {
124 	u32 addr;
125 	char name[TIPC_MAX_LINK_NAME];
126 	struct net *net;
127 
128 	/* Management and link supervision data */
129 	u32 peer_session;
130 	u32 peer_bearer_id;
131 	u32 bearer_id;
132 	u32 tolerance;
133 	unsigned long keepalive_intv;
134 	u32 abort_limit;
135 	u32 state;
136 	u16 peer_caps;
137 	bool active;
138 	u32 silent_intv_cnt;
139 	struct {
140 		unchar hdr[INT_H_SIZE];
141 		unchar body[TIPC_MAX_IF_NAME];
142 	} proto_msg;
143 	struct tipc_msg *pmsg;
144 	u32 priority;
145 	char net_plane;
146 
147 	/* Failover/synch */
148 	u16 drop_point;
149 	struct sk_buff *failover_reasm_skb;
150 
151 	/* Max packet negotiation */
152 	u16 mtu;
153 	u16 advertised_mtu;
154 
155 	/* Sending */
156 	struct sk_buff_head transmq;
157 	struct sk_buff_head backlogq;
158 	struct {
159 		u16 len;
160 		u16 limit;
161 	} backlog[5];
162 	u16 snd_nxt;
163 	u16 last_retransm;
164 	u16 window;
165 	u32 stale_count;
166 
167 	/* Reception */
168 	u16 rcv_nxt;
169 	u32 rcv_unacked;
170 	struct sk_buff_head deferdq;
171 	struct sk_buff_head *inputq;
172 	struct sk_buff_head *namedq;
173 
174 	/* Congestion handling */
175 	struct sk_buff_head wakeupq;
176 
177 	/* Fragmentation/reassembly */
178 	struct sk_buff *reasm_buf;
179 
180 	/* Broadcast */
181 	u16 ackers;
182 	u16 acked;
183 	struct tipc_link *bc_rcvlink;
184 	struct tipc_link *bc_sndlink;
185 	int nack_state;
186 	bool bc_peer_is_up;
187 
188 	/* Statistics */
189 	struct tipc_stats stats;
190 };
191 
192 /*
193  * Error message prefixes
194  */
195 static const char *link_co_err = "Link tunneling error, ";
196 static const char *link_rst_msg = "Resetting link ";
197 
198 /* Properties valid for media, bearar and link */
199 static const struct nla_policy tipc_nl_prop_policy[TIPC_NLA_PROP_MAX + 1] = {
200 	[TIPC_NLA_PROP_UNSPEC]		= { .type = NLA_UNSPEC },
201 	[TIPC_NLA_PROP_PRIO]		= { .type = NLA_U32 },
202 	[TIPC_NLA_PROP_TOL]		= { .type = NLA_U32 },
203 	[TIPC_NLA_PROP_WIN]		= { .type = NLA_U32 }
204 };
205 
206 /* Send states for broadcast NACKs
207  */
208 enum {
209 	BC_NACK_SND_CONDITIONAL,
210 	BC_NACK_SND_UNCONDITIONAL,
211 	BC_NACK_SND_SUPPRESS,
212 };
213 
214 /*
215  * Interval between NACKs when packets arrive out of order
216  */
217 #define TIPC_NACK_INTV (TIPC_MIN_LINK_WIN * 2)
218 /*
219  * Out-of-range value for link session numbers
220  */
221 #define WILDCARD_SESSION 0x10000
222 
223 /* Link FSM states:
224  */
225 enum {
226 	LINK_ESTABLISHED     = 0xe,
227 	LINK_ESTABLISHING    = 0xe  << 4,
228 	LINK_RESET           = 0x1  << 8,
229 	LINK_RESETTING       = 0x2  << 12,
230 	LINK_PEER_RESET      = 0xd  << 16,
231 	LINK_FAILINGOVER     = 0xf  << 20,
232 	LINK_SYNCHING        = 0xc  << 24
233 };
234 
235 /* Link FSM state checking routines
236  */
237 static int link_is_up(struct tipc_link *l)
238 {
239 	return l->state & (LINK_ESTABLISHED | LINK_SYNCHING);
240 }
241 
242 static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
243 			       struct sk_buff_head *xmitq);
244 static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
245 				      u16 rcvgap, int tolerance, int priority,
246 				      struct sk_buff_head *xmitq);
247 static void link_print(struct tipc_link *l, const char *str);
248 static void tipc_link_build_nack_msg(struct tipc_link *l,
249 				     struct sk_buff_head *xmitq);
250 static void tipc_link_build_bc_init_msg(struct tipc_link *l,
251 					struct sk_buff_head *xmitq);
252 static bool tipc_link_release_pkts(struct tipc_link *l, u16 to);
253 
254 /*
255  *  Simple non-static link routines (i.e. referenced outside this file)
256  */
257 bool tipc_link_is_up(struct tipc_link *l)
258 {
259 	return link_is_up(l);
260 }
261 
262 bool tipc_link_peer_is_down(struct tipc_link *l)
263 {
264 	return l->state == LINK_PEER_RESET;
265 }
266 
267 bool tipc_link_is_reset(struct tipc_link *l)
268 {
269 	return l->state & (LINK_RESET | LINK_FAILINGOVER | LINK_ESTABLISHING);
270 }
271 
272 bool tipc_link_is_establishing(struct tipc_link *l)
273 {
274 	return l->state == LINK_ESTABLISHING;
275 }
276 
277 bool tipc_link_is_synching(struct tipc_link *l)
278 {
279 	return l->state == LINK_SYNCHING;
280 }
281 
282 bool tipc_link_is_failingover(struct tipc_link *l)
283 {
284 	return l->state == LINK_FAILINGOVER;
285 }
286 
287 bool tipc_link_is_blocked(struct tipc_link *l)
288 {
289 	return l->state & (LINK_RESETTING | LINK_PEER_RESET | LINK_FAILINGOVER);
290 }
291 
292 static bool link_is_bc_sndlink(struct tipc_link *l)
293 {
294 	return !l->bc_sndlink;
295 }
296 
297 static bool link_is_bc_rcvlink(struct tipc_link *l)
298 {
299 	return ((l->bc_rcvlink == l) && !link_is_bc_sndlink(l));
300 }
301 
302 int tipc_link_is_active(struct tipc_link *l)
303 {
304 	return l->active;
305 }
306 
307 void tipc_link_set_active(struct tipc_link *l, bool active)
308 {
309 	l->active = active;
310 }
311 
312 u32 tipc_link_id(struct tipc_link *l)
313 {
314 	return l->peer_bearer_id << 16 | l->bearer_id;
315 }
316 
317 int tipc_link_window(struct tipc_link *l)
318 {
319 	return l->window;
320 }
321 
322 int tipc_link_prio(struct tipc_link *l)
323 {
324 	return l->priority;
325 }
326 
327 unsigned long tipc_link_tolerance(struct tipc_link *l)
328 {
329 	return l->tolerance;
330 }
331 
332 struct sk_buff_head *tipc_link_inputq(struct tipc_link *l)
333 {
334 	return l->inputq;
335 }
336 
337 char tipc_link_plane(struct tipc_link *l)
338 {
339 	return l->net_plane;
340 }
341 
342 void tipc_link_add_bc_peer(struct tipc_link *snd_l,
343 			   struct tipc_link *uc_l,
344 			   struct sk_buff_head *xmitq)
345 {
346 	struct tipc_link *rcv_l = uc_l->bc_rcvlink;
347 
348 	snd_l->ackers++;
349 	rcv_l->acked = snd_l->snd_nxt - 1;
350 	snd_l->state = LINK_ESTABLISHED;
351 	tipc_link_build_bc_init_msg(uc_l, xmitq);
352 }
353 
354 void tipc_link_remove_bc_peer(struct tipc_link *snd_l,
355 			      struct tipc_link *rcv_l,
356 			      struct sk_buff_head *xmitq)
357 {
358 	u16 ack = snd_l->snd_nxt - 1;
359 
360 	snd_l->ackers--;
361 	tipc_link_bc_ack_rcv(rcv_l, ack, xmitq);
362 	tipc_link_reset(rcv_l);
363 	rcv_l->state = LINK_RESET;
364 	if (!snd_l->ackers) {
365 		tipc_link_reset(snd_l);
366 		snd_l->state = LINK_RESET;
367 		__skb_queue_purge(xmitq);
368 	}
369 }
370 
371 int tipc_link_bc_peers(struct tipc_link *l)
372 {
373 	return l->ackers;
374 }
375 
376 void tipc_link_set_mtu(struct tipc_link *l, int mtu)
377 {
378 	l->mtu = mtu;
379 }
380 
381 int tipc_link_mtu(struct tipc_link *l)
382 {
383 	return l->mtu;
384 }
385 
386 u16 tipc_link_rcv_nxt(struct tipc_link *l)
387 {
388 	return l->rcv_nxt;
389 }
390 
391 u16 tipc_link_acked(struct tipc_link *l)
392 {
393 	return l->acked;
394 }
395 
396 char *tipc_link_name(struct tipc_link *l)
397 {
398 	return l->name;
399 }
400 
401 static u32 link_own_addr(struct tipc_link *l)
402 {
403 	return msg_prevnode(l->pmsg);
404 }
405 
406 void tipc_link_reinit(struct tipc_link *l, u32 addr)
407 {
408 	msg_set_prevnode(l->pmsg, addr);
409 }
410 
411 /**
412  * tipc_link_create - create a new link
413  * @n: pointer to associated node
414  * @if_name: associated interface name
415  * @bearer_id: id (index) of associated bearer
416  * @tolerance: link tolerance to be used by link
417  * @net_plane: network plane (A,B,c..) this link belongs to
418  * @mtu: mtu to be advertised by link
419  * @priority: priority to be used by link
420  * @window: send window to be used by link
421  * @session: session to be used by link
422  * @ownnode: identity of own node
423  * @peer: node id of peer node
424  * @peer_caps: bitmap describing peer node capabilities
425  * @bc_sndlink: the namespace global link used for broadcast sending
426  * @bc_rcvlink: the peer specific link used for broadcast reception
427  * @inputq: queue to put messages ready for delivery
428  * @namedq: queue to put binding table update messages ready for delivery
429  * @link: return value, pointer to put the created link
430  *
431  * Returns true if link was created, otherwise false
432  */
433 bool tipc_link_create(struct net *net, char *if_name, int bearer_id,
434 		      int tolerance, char net_plane, u32 mtu, int priority,
435 		      int window, u32 session, u32 ownnode, u32 peer,
436 		      u16 peer_caps,
437 		      struct tipc_link *bc_sndlink,
438 		      struct tipc_link *bc_rcvlink,
439 		      struct sk_buff_head *inputq,
440 		      struct sk_buff_head *namedq,
441 		      struct tipc_link **link)
442 {
443 	struct tipc_link *l;
444 	struct tipc_msg *hdr;
445 
446 	l = kzalloc(sizeof(*l), GFP_ATOMIC);
447 	if (!l)
448 		return false;
449 	*link = l;
450 	l->pmsg = (struct tipc_msg *)&l->proto_msg;
451 	hdr = l->pmsg;
452 	tipc_msg_init(ownnode, hdr, LINK_PROTOCOL, RESET_MSG, INT_H_SIZE, peer);
453 	msg_set_size(hdr, sizeof(l->proto_msg));
454 	msg_set_session(hdr, session);
455 	msg_set_bearer_id(hdr, l->bearer_id);
456 
457 	/* Note: peer i/f name is completed by reset/activate message */
458 	sprintf(l->name, "%u.%u.%u:%s-%u.%u.%u:unknown",
459 		tipc_zone(ownnode), tipc_cluster(ownnode), tipc_node(ownnode),
460 		if_name, tipc_zone(peer), tipc_cluster(peer), tipc_node(peer));
461 	strcpy((char *)msg_data(hdr), if_name);
462 
463 	l->addr = peer;
464 	l->peer_caps = peer_caps;
465 	l->net = net;
466 	l->peer_session = WILDCARD_SESSION;
467 	l->bearer_id = bearer_id;
468 	l->tolerance = tolerance;
469 	l->net_plane = net_plane;
470 	l->advertised_mtu = mtu;
471 	l->mtu = mtu;
472 	l->priority = priority;
473 	tipc_link_set_queue_limits(l, window);
474 	l->ackers = 1;
475 	l->bc_sndlink = bc_sndlink;
476 	l->bc_rcvlink = bc_rcvlink;
477 	l->inputq = inputq;
478 	l->namedq = namedq;
479 	l->state = LINK_RESETTING;
480 	__skb_queue_head_init(&l->transmq);
481 	__skb_queue_head_init(&l->backlogq);
482 	__skb_queue_head_init(&l->deferdq);
483 	skb_queue_head_init(&l->wakeupq);
484 	skb_queue_head_init(l->inputq);
485 	return true;
486 }
487 
488 /**
489  * tipc_link_bc_create - create new link to be used for broadcast
490  * @n: pointer to associated node
491  * @mtu: mtu to be used
492  * @window: send window to be used
493  * @inputq: queue to put messages ready for delivery
494  * @namedq: queue to put binding table update messages ready for delivery
495  * @link: return value, pointer to put the created link
496  *
497  * Returns true if link was created, otherwise false
498  */
499 bool tipc_link_bc_create(struct net *net, u32 ownnode, u32 peer,
500 			 int mtu, int window, u16 peer_caps,
501 			 struct sk_buff_head *inputq,
502 			 struct sk_buff_head *namedq,
503 			 struct tipc_link *bc_sndlink,
504 			 struct tipc_link **link)
505 {
506 	struct tipc_link *l;
507 
508 	if (!tipc_link_create(net, "", MAX_BEARERS, 0, 'Z', mtu, 0, window,
509 			      0, ownnode, peer, peer_caps, bc_sndlink,
510 			      NULL, inputq, namedq, link))
511 		return false;
512 
513 	l = *link;
514 	strcpy(l->name, tipc_bclink_name);
515 	tipc_link_reset(l);
516 	l->state = LINK_RESET;
517 	l->ackers = 0;
518 	l->bc_rcvlink = l;
519 
520 	/* Broadcast send link is always up */
521 	if (link_is_bc_sndlink(l))
522 		l->state = LINK_ESTABLISHED;
523 
524 	return true;
525 }
526 
527 /**
528  * tipc_link_fsm_evt - link finite state machine
529  * @l: pointer to link
530  * @evt: state machine event to be processed
531  */
532 int tipc_link_fsm_evt(struct tipc_link *l, int evt)
533 {
534 	int rc = 0;
535 
536 	switch (l->state) {
537 	case LINK_RESETTING:
538 		switch (evt) {
539 		case LINK_PEER_RESET_EVT:
540 			l->state = LINK_PEER_RESET;
541 			break;
542 		case LINK_RESET_EVT:
543 			l->state = LINK_RESET;
544 			break;
545 		case LINK_FAILURE_EVT:
546 		case LINK_FAILOVER_BEGIN_EVT:
547 		case LINK_ESTABLISH_EVT:
548 		case LINK_FAILOVER_END_EVT:
549 		case LINK_SYNCH_BEGIN_EVT:
550 		case LINK_SYNCH_END_EVT:
551 		default:
552 			goto illegal_evt;
553 		}
554 		break;
555 	case LINK_RESET:
556 		switch (evt) {
557 		case LINK_PEER_RESET_EVT:
558 			l->state = LINK_ESTABLISHING;
559 			break;
560 		case LINK_FAILOVER_BEGIN_EVT:
561 			l->state = LINK_FAILINGOVER;
562 		case LINK_FAILURE_EVT:
563 		case LINK_RESET_EVT:
564 		case LINK_ESTABLISH_EVT:
565 		case LINK_FAILOVER_END_EVT:
566 			break;
567 		case LINK_SYNCH_BEGIN_EVT:
568 		case LINK_SYNCH_END_EVT:
569 		default:
570 			goto illegal_evt;
571 		}
572 		break;
573 	case LINK_PEER_RESET:
574 		switch (evt) {
575 		case LINK_RESET_EVT:
576 			l->state = LINK_ESTABLISHING;
577 			break;
578 		case LINK_PEER_RESET_EVT:
579 		case LINK_ESTABLISH_EVT:
580 		case LINK_FAILURE_EVT:
581 			break;
582 		case LINK_SYNCH_BEGIN_EVT:
583 		case LINK_SYNCH_END_EVT:
584 		case LINK_FAILOVER_BEGIN_EVT:
585 		case LINK_FAILOVER_END_EVT:
586 		default:
587 			goto illegal_evt;
588 		}
589 		break;
590 	case LINK_FAILINGOVER:
591 		switch (evt) {
592 		case LINK_FAILOVER_END_EVT:
593 			l->state = LINK_RESET;
594 			break;
595 		case LINK_PEER_RESET_EVT:
596 		case LINK_RESET_EVT:
597 		case LINK_ESTABLISH_EVT:
598 		case LINK_FAILURE_EVT:
599 			break;
600 		case LINK_FAILOVER_BEGIN_EVT:
601 		case LINK_SYNCH_BEGIN_EVT:
602 		case LINK_SYNCH_END_EVT:
603 		default:
604 			goto illegal_evt;
605 		}
606 		break;
607 	case LINK_ESTABLISHING:
608 		switch (evt) {
609 		case LINK_ESTABLISH_EVT:
610 			l->state = LINK_ESTABLISHED;
611 			break;
612 		case LINK_FAILOVER_BEGIN_EVT:
613 			l->state = LINK_FAILINGOVER;
614 			break;
615 		case LINK_RESET_EVT:
616 			l->state = LINK_RESET;
617 			break;
618 		case LINK_FAILURE_EVT:
619 		case LINK_PEER_RESET_EVT:
620 		case LINK_SYNCH_BEGIN_EVT:
621 		case LINK_FAILOVER_END_EVT:
622 			break;
623 		case LINK_SYNCH_END_EVT:
624 		default:
625 			goto illegal_evt;
626 		}
627 		break;
628 	case LINK_ESTABLISHED:
629 		switch (evt) {
630 		case LINK_PEER_RESET_EVT:
631 			l->state = LINK_PEER_RESET;
632 			rc |= TIPC_LINK_DOWN_EVT;
633 			break;
634 		case LINK_FAILURE_EVT:
635 			l->state = LINK_RESETTING;
636 			rc |= TIPC_LINK_DOWN_EVT;
637 			break;
638 		case LINK_RESET_EVT:
639 			l->state = LINK_RESET;
640 			break;
641 		case LINK_ESTABLISH_EVT:
642 		case LINK_SYNCH_END_EVT:
643 			break;
644 		case LINK_SYNCH_BEGIN_EVT:
645 			l->state = LINK_SYNCHING;
646 			break;
647 		case LINK_FAILOVER_BEGIN_EVT:
648 		case LINK_FAILOVER_END_EVT:
649 		default:
650 			goto illegal_evt;
651 		}
652 		break;
653 	case LINK_SYNCHING:
654 		switch (evt) {
655 		case LINK_PEER_RESET_EVT:
656 			l->state = LINK_PEER_RESET;
657 			rc |= TIPC_LINK_DOWN_EVT;
658 			break;
659 		case LINK_FAILURE_EVT:
660 			l->state = LINK_RESETTING;
661 			rc |= TIPC_LINK_DOWN_EVT;
662 			break;
663 		case LINK_RESET_EVT:
664 			l->state = LINK_RESET;
665 			break;
666 		case LINK_ESTABLISH_EVT:
667 		case LINK_SYNCH_BEGIN_EVT:
668 			break;
669 		case LINK_SYNCH_END_EVT:
670 			l->state = LINK_ESTABLISHED;
671 			break;
672 		case LINK_FAILOVER_BEGIN_EVT:
673 		case LINK_FAILOVER_END_EVT:
674 		default:
675 			goto illegal_evt;
676 		}
677 		break;
678 	default:
679 		pr_err("Unknown FSM state %x in %s\n", l->state, l->name);
680 	}
681 	return rc;
682 illegal_evt:
683 	pr_err("Illegal FSM event %x in state %x on link %s\n",
684 	       evt, l->state, l->name);
685 	return rc;
686 }
687 
688 /* link_profile_stats - update statistical profiling of traffic
689  */
690 static void link_profile_stats(struct tipc_link *l)
691 {
692 	struct sk_buff *skb;
693 	struct tipc_msg *msg;
694 	int length;
695 
696 	/* Update counters used in statistical profiling of send traffic */
697 	l->stats.accu_queue_sz += skb_queue_len(&l->transmq);
698 	l->stats.queue_sz_counts++;
699 
700 	skb = skb_peek(&l->transmq);
701 	if (!skb)
702 		return;
703 	msg = buf_msg(skb);
704 	length = msg_size(msg);
705 
706 	if (msg_user(msg) == MSG_FRAGMENTER) {
707 		if (msg_type(msg) != FIRST_FRAGMENT)
708 			return;
709 		length = msg_size(msg_get_wrapped(msg));
710 	}
711 	l->stats.msg_lengths_total += length;
712 	l->stats.msg_length_counts++;
713 	if (length <= 64)
714 		l->stats.msg_length_profile[0]++;
715 	else if (length <= 256)
716 		l->stats.msg_length_profile[1]++;
717 	else if (length <= 1024)
718 		l->stats.msg_length_profile[2]++;
719 	else if (length <= 4096)
720 		l->stats.msg_length_profile[3]++;
721 	else if (length <= 16384)
722 		l->stats.msg_length_profile[4]++;
723 	else if (length <= 32768)
724 		l->stats.msg_length_profile[5]++;
725 	else
726 		l->stats.msg_length_profile[6]++;
727 }
728 
729 /* tipc_link_timeout - perform periodic task as instructed from node timeout
730  */
731 /* tipc_link_timeout - perform periodic task as instructed from node timeout
732  */
733 int tipc_link_timeout(struct tipc_link *l, struct sk_buff_head *xmitq)
734 {
735 	int rc = 0;
736 	int mtyp = STATE_MSG;
737 	bool xmit = false;
738 	bool prb = false;
739 	u16 bc_snt = l->bc_sndlink->snd_nxt - 1;
740 	u16 bc_acked = l->bc_rcvlink->acked;
741 	bool bc_up = link_is_up(l->bc_rcvlink);
742 
743 	link_profile_stats(l);
744 
745 	switch (l->state) {
746 	case LINK_ESTABLISHED:
747 	case LINK_SYNCHING:
748 		if (!l->silent_intv_cnt) {
749 			if (bc_up && (bc_acked != bc_snt))
750 				xmit = true;
751 		} else if (l->silent_intv_cnt <= l->abort_limit) {
752 			xmit = true;
753 			prb = true;
754 		} else {
755 			rc |= tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
756 		}
757 		l->silent_intv_cnt++;
758 		break;
759 	case LINK_RESET:
760 		xmit = true;
761 		mtyp = RESET_MSG;
762 		break;
763 	case LINK_ESTABLISHING:
764 		xmit = true;
765 		mtyp = ACTIVATE_MSG;
766 		break;
767 	case LINK_PEER_RESET:
768 	case LINK_RESETTING:
769 	case LINK_FAILINGOVER:
770 		break;
771 	default:
772 		break;
773 	}
774 
775 	if (xmit)
776 		tipc_link_build_proto_msg(l, mtyp, prb, 0, 0, 0, xmitq);
777 
778 	return rc;
779 }
780 
781 /**
782  * link_schedule_user - schedule a message sender for wakeup after congestion
783  * @link: congested link
784  * @list: message that was attempted sent
785  * Create pseudo msg to send back to user when congestion abates
786  * Does not consume buffer list
787  */
788 static int link_schedule_user(struct tipc_link *link, struct sk_buff_head *list)
789 {
790 	struct tipc_msg *msg = buf_msg(skb_peek(list));
791 	int imp = msg_importance(msg);
792 	u32 oport = msg_origport(msg);
793 	u32 addr = link_own_addr(link);
794 	struct sk_buff *skb;
795 
796 	/* This really cannot happen...  */
797 	if (unlikely(imp > TIPC_CRITICAL_IMPORTANCE)) {
798 		pr_warn("%s<%s>, send queue full", link_rst_msg, link->name);
799 		return -ENOBUFS;
800 	}
801 	/* Non-blocking sender: */
802 	if (TIPC_SKB_CB(skb_peek(list))->wakeup_pending)
803 		return -ELINKCONG;
804 
805 	/* Create and schedule wakeup pseudo message */
806 	skb = tipc_msg_create(SOCK_WAKEUP, 0, INT_H_SIZE, 0,
807 			      addr, addr, oport, 0, 0);
808 	if (!skb)
809 		return -ENOBUFS;
810 	TIPC_SKB_CB(skb)->chain_sz = skb_queue_len(list);
811 	TIPC_SKB_CB(skb)->chain_imp = imp;
812 	skb_queue_tail(&link->wakeupq, skb);
813 	link->stats.link_congs++;
814 	return -ELINKCONG;
815 }
816 
817 /**
818  * link_prepare_wakeup - prepare users for wakeup after congestion
819  * @link: congested link
820  * Move a number of waiting users, as permitted by available space in
821  * the send queue, from link wait queue to node wait queue for wakeup
822  */
823 void link_prepare_wakeup(struct tipc_link *l)
824 {
825 	int pnd[TIPC_SYSTEM_IMPORTANCE + 1] = {0,};
826 	int imp, lim;
827 	struct sk_buff *skb, *tmp;
828 
829 	skb_queue_walk_safe(&l->wakeupq, skb, tmp) {
830 		imp = TIPC_SKB_CB(skb)->chain_imp;
831 		lim = l->window + l->backlog[imp].limit;
832 		pnd[imp] += TIPC_SKB_CB(skb)->chain_sz;
833 		if ((pnd[imp] + l->backlog[imp].len) >= lim)
834 			break;
835 		skb_unlink(skb, &l->wakeupq);
836 		skb_queue_tail(l->inputq, skb);
837 	}
838 }
839 
840 void tipc_link_reset(struct tipc_link *l)
841 {
842 	/* Link is down, accept any session */
843 	l->peer_session = WILDCARD_SESSION;
844 
845 	/* If peer is up, it only accepts an incremented session number */
846 	msg_set_session(l->pmsg, msg_session(l->pmsg) + 1);
847 
848 	/* Prepare for renewed mtu size negotiation */
849 	l->mtu = l->advertised_mtu;
850 
851 	/* Clean up all queues and counters: */
852 	__skb_queue_purge(&l->transmq);
853 	__skb_queue_purge(&l->deferdq);
854 	skb_queue_splice_init(&l->wakeupq, l->inputq);
855 	__skb_queue_purge(&l->backlogq);
856 	l->backlog[TIPC_LOW_IMPORTANCE].len = 0;
857 	l->backlog[TIPC_MEDIUM_IMPORTANCE].len = 0;
858 	l->backlog[TIPC_HIGH_IMPORTANCE].len = 0;
859 	l->backlog[TIPC_CRITICAL_IMPORTANCE].len = 0;
860 	l->backlog[TIPC_SYSTEM_IMPORTANCE].len = 0;
861 	kfree_skb(l->reasm_buf);
862 	kfree_skb(l->failover_reasm_skb);
863 	l->reasm_buf = NULL;
864 	l->failover_reasm_skb = NULL;
865 	l->rcv_unacked = 0;
866 	l->snd_nxt = 1;
867 	l->rcv_nxt = 1;
868 	l->acked = 0;
869 	l->silent_intv_cnt = 0;
870 	l->stats.recv_info = 0;
871 	l->stale_count = 0;
872 	l->bc_peer_is_up = false;
873 	tipc_link_reset_stats(l);
874 }
875 
876 /**
877  * tipc_link_xmit(): enqueue buffer list according to queue situation
878  * @link: link to use
879  * @list: chain of buffers containing message
880  * @xmitq: returned list of packets to be sent by caller
881  *
882  * Consumes the buffer chain, except when returning -ELINKCONG,
883  * since the caller then may want to make more send attempts.
884  * Returns 0 if success, or errno: -ELINKCONG, -EMSGSIZE or -ENOBUFS
885  * Messages at TIPC_SYSTEM_IMPORTANCE are always accepted
886  */
887 int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *list,
888 		   struct sk_buff_head *xmitq)
889 {
890 	struct tipc_msg *hdr = buf_msg(skb_peek(list));
891 	unsigned int maxwin = l->window;
892 	unsigned int i, imp = msg_importance(hdr);
893 	unsigned int mtu = l->mtu;
894 	u16 ack = l->rcv_nxt - 1;
895 	u16 seqno = l->snd_nxt;
896 	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
897 	struct sk_buff_head *transmq = &l->transmq;
898 	struct sk_buff_head *backlogq = &l->backlogq;
899 	struct sk_buff *skb, *_skb, *bskb;
900 
901 	/* Match msg importance against this and all higher backlog limits: */
902 	for (i = imp; i <= TIPC_SYSTEM_IMPORTANCE; i++) {
903 		if (unlikely(l->backlog[i].len >= l->backlog[i].limit))
904 			return link_schedule_user(l, list);
905 	}
906 	if (unlikely(msg_size(hdr) > mtu)) {
907 		skb_queue_purge(list);
908 		return -EMSGSIZE;
909 	}
910 
911 	/* Prepare each packet for sending, and add to relevant queue: */
912 	while (skb_queue_len(list)) {
913 		skb = skb_peek(list);
914 		hdr = buf_msg(skb);
915 		msg_set_seqno(hdr, seqno);
916 		msg_set_ack(hdr, ack);
917 		msg_set_bcast_ack(hdr, bc_ack);
918 
919 		if (likely(skb_queue_len(transmq) < maxwin)) {
920 			_skb = skb_clone(skb, GFP_ATOMIC);
921 			if (!_skb) {
922 				skb_queue_purge(list);
923 				return -ENOBUFS;
924 			}
925 			__skb_dequeue(list);
926 			__skb_queue_tail(transmq, skb);
927 			__skb_queue_tail(xmitq, _skb);
928 			TIPC_SKB_CB(skb)->ackers = l->ackers;
929 			l->rcv_unacked = 0;
930 			seqno++;
931 			continue;
932 		}
933 		if (tipc_msg_bundle(skb_peek_tail(backlogq), hdr, mtu)) {
934 			kfree_skb(__skb_dequeue(list));
935 			l->stats.sent_bundled++;
936 			continue;
937 		}
938 		if (tipc_msg_make_bundle(&bskb, hdr, mtu, l->addr)) {
939 			kfree_skb(__skb_dequeue(list));
940 			__skb_queue_tail(backlogq, bskb);
941 			l->backlog[msg_importance(buf_msg(bskb))].len++;
942 			l->stats.sent_bundled++;
943 			l->stats.sent_bundles++;
944 			continue;
945 		}
946 		l->backlog[imp].len += skb_queue_len(list);
947 		skb_queue_splice_tail_init(list, backlogq);
948 	}
949 	l->snd_nxt = seqno;
950 	return 0;
951 }
952 
953 void tipc_link_advance_backlog(struct tipc_link *l, struct sk_buff_head *xmitq)
954 {
955 	struct sk_buff *skb, *_skb;
956 	struct tipc_msg *hdr;
957 	u16 seqno = l->snd_nxt;
958 	u16 ack = l->rcv_nxt - 1;
959 	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
960 
961 	while (skb_queue_len(&l->transmq) < l->window) {
962 		skb = skb_peek(&l->backlogq);
963 		if (!skb)
964 			break;
965 		_skb = skb_clone(skb, GFP_ATOMIC);
966 		if (!_skb)
967 			break;
968 		__skb_dequeue(&l->backlogq);
969 		hdr = buf_msg(skb);
970 		l->backlog[msg_importance(hdr)].len--;
971 		__skb_queue_tail(&l->transmq, skb);
972 		__skb_queue_tail(xmitq, _skb);
973 		TIPC_SKB_CB(skb)->ackers = l->ackers;
974 		msg_set_seqno(hdr, seqno);
975 		msg_set_ack(hdr, ack);
976 		msg_set_bcast_ack(hdr, bc_ack);
977 		l->rcv_unacked = 0;
978 		seqno++;
979 	}
980 	l->snd_nxt = seqno;
981 }
982 
983 static void link_retransmit_failure(struct tipc_link *l, struct sk_buff *skb)
984 {
985 	struct tipc_msg *hdr = buf_msg(skb);
986 
987 	pr_warn("Retransmission failure on link <%s>\n", l->name);
988 	link_print(l, "Resetting link ");
989 	pr_info("Failed msg: usr %u, typ %u, len %u, err %u\n",
990 		msg_user(hdr), msg_type(hdr), msg_size(hdr), msg_errcode(hdr));
991 	pr_info("sqno %u, prev: %x, src: %x\n",
992 		msg_seqno(hdr), msg_prevnode(hdr), msg_orignode(hdr));
993 }
994 
995 int tipc_link_retrans(struct tipc_link *l, u16 from, u16 to,
996 		      struct sk_buff_head *xmitq)
997 {
998 	struct sk_buff *_skb, *skb = skb_peek(&l->transmq);
999 	struct tipc_msg *hdr;
1000 	u16 ack = l->rcv_nxt - 1;
1001 	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
1002 
1003 	if (!skb)
1004 		return 0;
1005 
1006 	/* Detect repeated retransmit failures on same packet */
1007 	if (likely(l->last_retransm != buf_seqno(skb))) {
1008 		l->last_retransm = buf_seqno(skb);
1009 		l->stale_count = 1;
1010 	} else if (++l->stale_count > 100) {
1011 		link_retransmit_failure(l, skb);
1012 		return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1013 	}
1014 
1015 	/* Move forward to where retransmission should start */
1016 	skb_queue_walk(&l->transmq, skb) {
1017 		if (!less(buf_seqno(skb), from))
1018 			break;
1019 	}
1020 
1021 	skb_queue_walk_from(&l->transmq, skb) {
1022 		if (more(buf_seqno(skb), to))
1023 			break;
1024 		hdr = buf_msg(skb);
1025 		_skb = __pskb_copy(skb, MIN_H_SIZE, GFP_ATOMIC);
1026 		if (!_skb)
1027 			return 0;
1028 		hdr = buf_msg(_skb);
1029 		msg_set_ack(hdr, ack);
1030 		msg_set_bcast_ack(hdr, bc_ack);
1031 		_skb->priority = TC_PRIO_CONTROL;
1032 		__skb_queue_tail(xmitq, _skb);
1033 		l->stats.retransmitted++;
1034 	}
1035 	return 0;
1036 }
1037 
1038 /* tipc_data_input - deliver data and name distr msgs to upper layer
1039  *
1040  * Consumes buffer if message is of right type
1041  * Node lock must be held
1042  */
1043 static bool tipc_data_input(struct tipc_link *l, struct sk_buff *skb,
1044 			    struct sk_buff_head *inputq)
1045 {
1046 	switch (msg_user(buf_msg(skb))) {
1047 	case TIPC_LOW_IMPORTANCE:
1048 	case TIPC_MEDIUM_IMPORTANCE:
1049 	case TIPC_HIGH_IMPORTANCE:
1050 	case TIPC_CRITICAL_IMPORTANCE:
1051 	case CONN_MANAGER:
1052 		skb_queue_tail(inputq, skb);
1053 		return true;
1054 	case NAME_DISTRIBUTOR:
1055 		l->bc_rcvlink->state = LINK_ESTABLISHED;
1056 		skb_queue_tail(l->namedq, skb);
1057 		return true;
1058 	case MSG_BUNDLER:
1059 	case TUNNEL_PROTOCOL:
1060 	case MSG_FRAGMENTER:
1061 	case BCAST_PROTOCOL:
1062 		return false;
1063 	default:
1064 		pr_warn("Dropping received illegal msg type\n");
1065 		kfree_skb(skb);
1066 		return false;
1067 	};
1068 }
1069 
1070 /* tipc_link_input - process packet that has passed link protocol check
1071  *
1072  * Consumes buffer
1073  */
1074 static int tipc_link_input(struct tipc_link *l, struct sk_buff *skb,
1075 			   struct sk_buff_head *inputq)
1076 {
1077 	struct tipc_msg *hdr = buf_msg(skb);
1078 	struct sk_buff **reasm_skb = &l->reasm_buf;
1079 	struct sk_buff *iskb;
1080 	struct sk_buff_head tmpq;
1081 	int usr = msg_user(hdr);
1082 	int rc = 0;
1083 	int pos = 0;
1084 	int ipos = 0;
1085 
1086 	if (unlikely(usr == TUNNEL_PROTOCOL)) {
1087 		if (msg_type(hdr) == SYNCH_MSG) {
1088 			__skb_queue_purge(&l->deferdq);
1089 			goto drop;
1090 		}
1091 		if (!tipc_msg_extract(skb, &iskb, &ipos))
1092 			return rc;
1093 		kfree_skb(skb);
1094 		skb = iskb;
1095 		hdr = buf_msg(skb);
1096 		if (less(msg_seqno(hdr), l->drop_point))
1097 			goto drop;
1098 		if (tipc_data_input(l, skb, inputq))
1099 			return rc;
1100 		usr = msg_user(hdr);
1101 		reasm_skb = &l->failover_reasm_skb;
1102 	}
1103 
1104 	if (usr == MSG_BUNDLER) {
1105 		skb_queue_head_init(&tmpq);
1106 		l->stats.recv_bundles++;
1107 		l->stats.recv_bundled += msg_msgcnt(hdr);
1108 		while (tipc_msg_extract(skb, &iskb, &pos))
1109 			tipc_data_input(l, iskb, &tmpq);
1110 		tipc_skb_queue_splice_tail(&tmpq, inputq);
1111 		return 0;
1112 	} else if (usr == MSG_FRAGMENTER) {
1113 		l->stats.recv_fragments++;
1114 		if (tipc_buf_append(reasm_skb, &skb)) {
1115 			l->stats.recv_fragmented++;
1116 			tipc_data_input(l, skb, inputq);
1117 		} else if (!*reasm_skb && !link_is_bc_rcvlink(l)) {
1118 			pr_warn_ratelimited("Unable to build fragment list\n");
1119 			return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1120 		}
1121 		return 0;
1122 	} else if (usr == BCAST_PROTOCOL) {
1123 		tipc_bcast_lock(l->net);
1124 		tipc_link_bc_init_rcv(l->bc_rcvlink, hdr);
1125 		tipc_bcast_unlock(l->net);
1126 	}
1127 drop:
1128 	kfree_skb(skb);
1129 	return 0;
1130 }
1131 
1132 static bool tipc_link_release_pkts(struct tipc_link *l, u16 acked)
1133 {
1134 	bool released = false;
1135 	struct sk_buff *skb, *tmp;
1136 
1137 	skb_queue_walk_safe(&l->transmq, skb, tmp) {
1138 		if (more(buf_seqno(skb), acked))
1139 			break;
1140 		__skb_unlink(skb, &l->transmq);
1141 		kfree_skb(skb);
1142 		released = true;
1143 	}
1144 	return released;
1145 }
1146 
1147 /* tipc_link_build_ack_msg: prepare link acknowledge message for transmission
1148  *
1149  * Note that sending of broadcast ack is coordinated among nodes, to reduce
1150  * risk of ack storms towards the sender
1151  */
1152 int tipc_link_build_ack_msg(struct tipc_link *l, struct sk_buff_head *xmitq)
1153 {
1154 	if (!l)
1155 		return 0;
1156 
1157 	/* Broadcast ACK must be sent via a unicast link => defer to caller */
1158 	if (link_is_bc_rcvlink(l)) {
1159 		if (((l->rcv_nxt ^ link_own_addr(l)) & 0xf) != 0xf)
1160 			return 0;
1161 		l->rcv_unacked = 0;
1162 		return TIPC_LINK_SND_BC_ACK;
1163 	}
1164 
1165 	/* Unicast ACK */
1166 	l->rcv_unacked = 0;
1167 	l->stats.sent_acks++;
1168 	tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, 0, xmitq);
1169 	return 0;
1170 }
1171 
1172 /* tipc_link_build_reset_msg: prepare link RESET or ACTIVATE message
1173  */
1174 void tipc_link_build_reset_msg(struct tipc_link *l, struct sk_buff_head *xmitq)
1175 {
1176 	int mtyp = RESET_MSG;
1177 
1178 	if (l->state == LINK_ESTABLISHING)
1179 		mtyp = ACTIVATE_MSG;
1180 
1181 	tipc_link_build_proto_msg(l, mtyp, 0, 0, 0, 0, xmitq);
1182 }
1183 
1184 /* tipc_link_build_nack_msg: prepare link nack message for transmission
1185  */
1186 static void tipc_link_build_nack_msg(struct tipc_link *l,
1187 				     struct sk_buff_head *xmitq)
1188 {
1189 	u32 def_cnt = ++l->stats.deferred_recv;
1190 
1191 	if (link_is_bc_rcvlink(l))
1192 		return;
1193 
1194 	if ((skb_queue_len(&l->deferdq) == 1) || !(def_cnt % TIPC_NACK_INTV))
1195 		tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, 0, xmitq);
1196 }
1197 
1198 /* tipc_link_rcv - process TIPC packets/messages arriving from off-node
1199  * @l: the link that should handle the message
1200  * @skb: TIPC packet
1201  * @xmitq: queue to place packets to be sent after this call
1202  */
1203 int tipc_link_rcv(struct tipc_link *l, struct sk_buff *skb,
1204 		  struct sk_buff_head *xmitq)
1205 {
1206 	struct sk_buff_head *defq = &l->deferdq;
1207 	struct tipc_msg *hdr;
1208 	u16 seqno, rcv_nxt, win_lim;
1209 	int rc = 0;
1210 
1211 	do {
1212 		hdr = buf_msg(skb);
1213 		seqno = msg_seqno(hdr);
1214 		rcv_nxt = l->rcv_nxt;
1215 		win_lim = rcv_nxt + TIPC_MAX_LINK_WIN;
1216 
1217 		/* Verify and update link state */
1218 		if (unlikely(msg_user(hdr) == LINK_PROTOCOL))
1219 			return tipc_link_proto_rcv(l, skb, xmitq);
1220 
1221 		if (unlikely(!link_is_up(l))) {
1222 			if (l->state == LINK_ESTABLISHING)
1223 				rc = TIPC_LINK_UP_EVT;
1224 			goto drop;
1225 		}
1226 
1227 		/* Don't send probe at next timeout expiration */
1228 		l->silent_intv_cnt = 0;
1229 
1230 		/* Drop if outside receive window */
1231 		if (unlikely(less(seqno, rcv_nxt) || more(seqno, win_lim))) {
1232 			l->stats.duplicates++;
1233 			goto drop;
1234 		}
1235 
1236 		/* Forward queues and wake up waiting users */
1237 		if (likely(tipc_link_release_pkts(l, msg_ack(hdr)))) {
1238 			tipc_link_advance_backlog(l, xmitq);
1239 			if (unlikely(!skb_queue_empty(&l->wakeupq)))
1240 				link_prepare_wakeup(l);
1241 		}
1242 
1243 		/* Defer delivery if sequence gap */
1244 		if (unlikely(seqno != rcv_nxt)) {
1245 			__tipc_skb_queue_sorted(defq, seqno, skb);
1246 			tipc_link_build_nack_msg(l, xmitq);
1247 			break;
1248 		}
1249 
1250 		/* Deliver packet */
1251 		l->rcv_nxt++;
1252 		l->stats.recv_info++;
1253 		if (!tipc_data_input(l, skb, l->inputq))
1254 			rc |= tipc_link_input(l, skb, l->inputq);
1255 		if (unlikely(++l->rcv_unacked >= TIPC_MIN_LINK_WIN))
1256 			rc |= tipc_link_build_ack_msg(l, xmitq);
1257 		if (unlikely(rc & ~TIPC_LINK_SND_BC_ACK))
1258 			break;
1259 	} while ((skb = __skb_dequeue(defq)));
1260 
1261 	return rc;
1262 drop:
1263 	kfree_skb(skb);
1264 	return rc;
1265 }
1266 
1267 static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
1268 				      u16 rcvgap, int tolerance, int priority,
1269 				      struct sk_buff_head *xmitq)
1270 {
1271 	struct sk_buff *skb = NULL;
1272 	struct tipc_msg *hdr = l->pmsg;
1273 	bool node_up = link_is_up(l->bc_rcvlink);
1274 
1275 	/* Don't send protocol message during reset or link failover */
1276 	if (tipc_link_is_blocked(l))
1277 		return;
1278 
1279 	msg_set_type(hdr, mtyp);
1280 	msg_set_net_plane(hdr, l->net_plane);
1281 	msg_set_next_sent(hdr, l->snd_nxt);
1282 	msg_set_ack(hdr, l->rcv_nxt - 1);
1283 	msg_set_bcast_ack(hdr, l->bc_rcvlink->rcv_nxt - 1);
1284 	msg_set_last_bcast(hdr, l->bc_sndlink->snd_nxt - 1);
1285 	msg_set_link_tolerance(hdr, tolerance);
1286 	msg_set_linkprio(hdr, priority);
1287 	msg_set_redundant_link(hdr, node_up);
1288 	msg_set_seq_gap(hdr, 0);
1289 
1290 	/* Compatibility: created msg must not be in sequence with pkt flow */
1291 	msg_set_seqno(hdr, l->snd_nxt + U16_MAX / 2);
1292 
1293 	if (mtyp == STATE_MSG) {
1294 		if (!tipc_link_is_up(l))
1295 			return;
1296 
1297 		/* Override rcvgap if there are packets in deferred queue */
1298 		if (!skb_queue_empty(&l->deferdq))
1299 			rcvgap = buf_seqno(skb_peek(&l->deferdq)) - l->rcv_nxt;
1300 		if (rcvgap) {
1301 			msg_set_seq_gap(hdr, rcvgap);
1302 			l->stats.sent_nacks++;
1303 		}
1304 		msg_set_probe(hdr, probe);
1305 		if (probe)
1306 			l->stats.sent_probes++;
1307 		l->stats.sent_states++;
1308 		l->rcv_unacked = 0;
1309 	} else {
1310 		/* RESET_MSG or ACTIVATE_MSG */
1311 		msg_set_max_pkt(hdr, l->advertised_mtu);
1312 		msg_set_ack(hdr, l->rcv_nxt - 1);
1313 		msg_set_next_sent(hdr, 1);
1314 	}
1315 	skb = tipc_buf_acquire(msg_size(hdr));
1316 	if (!skb)
1317 		return;
1318 	skb_copy_to_linear_data(skb, hdr, msg_size(hdr));
1319 	skb->priority = TC_PRIO_CONTROL;
1320 	__skb_queue_tail(xmitq, skb);
1321 }
1322 
1323 /* tipc_link_tnl_prepare(): prepare and return a list of tunnel packets
1324  * with contents of the link's transmit and backlog queues.
1325  */
1326 void tipc_link_tnl_prepare(struct tipc_link *l, struct tipc_link *tnl,
1327 			   int mtyp, struct sk_buff_head *xmitq)
1328 {
1329 	struct sk_buff *skb, *tnlskb;
1330 	struct tipc_msg *hdr, tnlhdr;
1331 	struct sk_buff_head *queue = &l->transmq;
1332 	struct sk_buff_head tmpxq, tnlq;
1333 	u16 pktlen, pktcnt, seqno = l->snd_nxt;
1334 
1335 	if (!tnl)
1336 		return;
1337 
1338 	skb_queue_head_init(&tnlq);
1339 	skb_queue_head_init(&tmpxq);
1340 
1341 	/* At least one packet required for safe algorithm => add dummy */
1342 	skb = tipc_msg_create(TIPC_LOW_IMPORTANCE, TIPC_DIRECT_MSG,
1343 			      BASIC_H_SIZE, 0, l->addr, link_own_addr(l),
1344 			      0, 0, TIPC_ERR_NO_PORT);
1345 	if (!skb) {
1346 		pr_warn("%sunable to create tunnel packet\n", link_co_err);
1347 		return;
1348 	}
1349 	skb_queue_tail(&tnlq, skb);
1350 	tipc_link_xmit(l, &tnlq, &tmpxq);
1351 	__skb_queue_purge(&tmpxq);
1352 
1353 	/* Initialize reusable tunnel packet header */
1354 	tipc_msg_init(link_own_addr(l), &tnlhdr, TUNNEL_PROTOCOL,
1355 		      mtyp, INT_H_SIZE, l->addr);
1356 	pktcnt = skb_queue_len(&l->transmq) + skb_queue_len(&l->backlogq);
1357 	msg_set_msgcnt(&tnlhdr, pktcnt);
1358 	msg_set_bearer_id(&tnlhdr, l->peer_bearer_id);
1359 tnl:
1360 	/* Wrap each packet into a tunnel packet */
1361 	skb_queue_walk(queue, skb) {
1362 		hdr = buf_msg(skb);
1363 		if (queue == &l->backlogq)
1364 			msg_set_seqno(hdr, seqno++);
1365 		pktlen = msg_size(hdr);
1366 		msg_set_size(&tnlhdr, pktlen + INT_H_SIZE);
1367 		tnlskb = tipc_buf_acquire(pktlen + INT_H_SIZE);
1368 		if (!tnlskb) {
1369 			pr_warn("%sunable to send packet\n", link_co_err);
1370 			return;
1371 		}
1372 		skb_copy_to_linear_data(tnlskb, &tnlhdr, INT_H_SIZE);
1373 		skb_copy_to_linear_data_offset(tnlskb, INT_H_SIZE, hdr, pktlen);
1374 		__skb_queue_tail(&tnlq, tnlskb);
1375 	}
1376 	if (queue != &l->backlogq) {
1377 		queue = &l->backlogq;
1378 		goto tnl;
1379 	}
1380 
1381 	tipc_link_xmit(tnl, &tnlq, xmitq);
1382 
1383 	if (mtyp == FAILOVER_MSG) {
1384 		tnl->drop_point = l->rcv_nxt;
1385 		tnl->failover_reasm_skb = l->reasm_buf;
1386 		l->reasm_buf = NULL;
1387 	}
1388 }
1389 
1390 /* tipc_link_proto_rcv(): receive link level protocol message :
1391  * Note that network plane id propagates through the network, and may
1392  * change at any time. The node with lowest numerical id determines
1393  * network plane
1394  */
1395 static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
1396 			       struct sk_buff_head *xmitq)
1397 {
1398 	struct tipc_msg *hdr = buf_msg(skb);
1399 	u16 rcvgap = 0;
1400 	u16 ack = msg_ack(hdr);
1401 	u16 gap = msg_seq_gap(hdr);
1402 	u16 peers_snd_nxt =  msg_next_sent(hdr);
1403 	u16 peers_tol = msg_link_tolerance(hdr);
1404 	u16 peers_prio = msg_linkprio(hdr);
1405 	u16 rcv_nxt = l->rcv_nxt;
1406 	int mtyp = msg_type(hdr);
1407 	char *if_name;
1408 	int rc = 0;
1409 
1410 	if (tipc_link_is_blocked(l) || !xmitq)
1411 		goto exit;
1412 
1413 	if (link_own_addr(l) > msg_prevnode(hdr))
1414 		l->net_plane = msg_net_plane(hdr);
1415 
1416 	switch (mtyp) {
1417 	case RESET_MSG:
1418 
1419 		/* Ignore duplicate RESET with old session number */
1420 		if ((less_eq(msg_session(hdr), l->peer_session)) &&
1421 		    (l->peer_session != WILDCARD_SESSION))
1422 			break;
1423 		/* fall thru' */
1424 
1425 	case ACTIVATE_MSG:
1426 		skb_linearize(skb);
1427 		hdr = buf_msg(skb);
1428 
1429 		/* Complete own link name with peer's interface name */
1430 		if_name =  strrchr(l->name, ':') + 1;
1431 		if (sizeof(l->name) - (if_name - l->name) <= TIPC_MAX_IF_NAME)
1432 			break;
1433 		if (msg_data_sz(hdr) < TIPC_MAX_IF_NAME)
1434 			break;
1435 		strncpy(if_name, msg_data(hdr),	TIPC_MAX_IF_NAME);
1436 
1437 		/* Update own tolerance if peer indicates a non-zero value */
1438 		if (in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL))
1439 			l->tolerance = peers_tol;
1440 
1441 		/* Update own priority if peer's priority is higher */
1442 		if (in_range(peers_prio, l->priority + 1, TIPC_MAX_LINK_PRI))
1443 			l->priority = peers_prio;
1444 
1445 		/* ACTIVATE_MSG serves as PEER_RESET if link is already down */
1446 		if ((mtyp == RESET_MSG) || !link_is_up(l))
1447 			rc = tipc_link_fsm_evt(l, LINK_PEER_RESET_EVT);
1448 
1449 		/* ACTIVATE_MSG takes up link if it was already locally reset */
1450 		if ((mtyp == ACTIVATE_MSG) && (l->state == LINK_ESTABLISHING))
1451 			rc = TIPC_LINK_UP_EVT;
1452 
1453 		l->peer_session = msg_session(hdr);
1454 		l->peer_bearer_id = msg_bearer_id(hdr);
1455 		if (l->mtu > msg_max_pkt(hdr))
1456 			l->mtu = msg_max_pkt(hdr);
1457 		break;
1458 
1459 	case STATE_MSG:
1460 
1461 		/* Update own tolerance if peer indicates a non-zero value */
1462 		if (in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL))
1463 			l->tolerance = peers_tol;
1464 
1465 		if (peers_prio && in_range(peers_prio, TIPC_MIN_LINK_PRI,
1466 					   TIPC_MAX_LINK_PRI)) {
1467 			l->priority = peers_prio;
1468 			rc = tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1469 		}
1470 
1471 		l->silent_intv_cnt = 0;
1472 		l->stats.recv_states++;
1473 		if (msg_probe(hdr))
1474 			l->stats.recv_probes++;
1475 
1476 		if (!link_is_up(l)) {
1477 			if (l->state == LINK_ESTABLISHING)
1478 				rc = TIPC_LINK_UP_EVT;
1479 			break;
1480 		}
1481 
1482 		/* Send NACK if peer has sent pkts we haven't received yet */
1483 		if (more(peers_snd_nxt, rcv_nxt) && !tipc_link_is_synching(l))
1484 			rcvgap = peers_snd_nxt - l->rcv_nxt;
1485 		if (rcvgap || (msg_probe(hdr)))
1486 			tipc_link_build_proto_msg(l, STATE_MSG, 0, rcvgap,
1487 						  0, 0, xmitq);
1488 		tipc_link_release_pkts(l, ack);
1489 
1490 		/* If NACK, retransmit will now start at right position */
1491 		if (gap) {
1492 			rc = tipc_link_retrans(l, ack + 1, ack + gap, xmitq);
1493 			l->stats.recv_nacks++;
1494 		}
1495 
1496 		tipc_link_advance_backlog(l, xmitq);
1497 		if (unlikely(!skb_queue_empty(&l->wakeupq)))
1498 			link_prepare_wakeup(l);
1499 	}
1500 exit:
1501 	kfree_skb(skb);
1502 	return rc;
1503 }
1504 
1505 /* tipc_link_build_bc_proto_msg() - create broadcast protocol message
1506  */
1507 static bool tipc_link_build_bc_proto_msg(struct tipc_link *l, bool bcast,
1508 					 u16 peers_snd_nxt,
1509 					 struct sk_buff_head *xmitq)
1510 {
1511 	struct sk_buff *skb;
1512 	struct tipc_msg *hdr;
1513 	struct sk_buff *dfrd_skb = skb_peek(&l->deferdq);
1514 	u16 ack = l->rcv_nxt - 1;
1515 	u16 gap_to = peers_snd_nxt - 1;
1516 
1517 	skb = tipc_msg_create(BCAST_PROTOCOL, STATE_MSG, INT_H_SIZE,
1518 			      0, l->addr, link_own_addr(l), 0, 0, 0);
1519 	if (!skb)
1520 		return false;
1521 	hdr = buf_msg(skb);
1522 	msg_set_last_bcast(hdr, l->bc_sndlink->snd_nxt - 1);
1523 	msg_set_bcast_ack(hdr, ack);
1524 	msg_set_bcgap_after(hdr, ack);
1525 	if (dfrd_skb)
1526 		gap_to = buf_seqno(dfrd_skb) - 1;
1527 	msg_set_bcgap_to(hdr, gap_to);
1528 	msg_set_non_seq(hdr, bcast);
1529 	__skb_queue_tail(xmitq, skb);
1530 	return true;
1531 }
1532 
1533 /* tipc_link_build_bc_init_msg() - synchronize broadcast link endpoints.
1534  *
1535  * Give a newly added peer node the sequence number where it should
1536  * start receiving and acking broadcast packets.
1537  */
1538 static void tipc_link_build_bc_init_msg(struct tipc_link *l,
1539 					struct sk_buff_head *xmitq)
1540 {
1541 	struct sk_buff_head list;
1542 
1543 	__skb_queue_head_init(&list);
1544 	if (!tipc_link_build_bc_proto_msg(l->bc_rcvlink, false, 0, &list))
1545 		return;
1546 	tipc_link_xmit(l, &list, xmitq);
1547 }
1548 
1549 /* tipc_link_bc_init_rcv - receive initial broadcast synch data from peer
1550  */
1551 void tipc_link_bc_init_rcv(struct tipc_link *l, struct tipc_msg *hdr)
1552 {
1553 	int mtyp = msg_type(hdr);
1554 	u16 peers_snd_nxt = msg_bc_snd_nxt(hdr);
1555 
1556 	if (link_is_up(l))
1557 		return;
1558 
1559 	if (msg_user(hdr) == BCAST_PROTOCOL) {
1560 		l->rcv_nxt = peers_snd_nxt;
1561 		l->state = LINK_ESTABLISHED;
1562 		return;
1563 	}
1564 
1565 	if (l->peer_caps & TIPC_BCAST_SYNCH)
1566 		return;
1567 
1568 	if (msg_peer_node_is_up(hdr))
1569 		return;
1570 
1571 	/* Compatibility: accept older, less safe initial synch data */
1572 	if ((mtyp == RESET_MSG) || (mtyp == ACTIVATE_MSG))
1573 		l->rcv_nxt = peers_snd_nxt;
1574 }
1575 
1576 /* tipc_link_bc_sync_rcv - update rcv link according to peer's send state
1577  */
1578 void tipc_link_bc_sync_rcv(struct tipc_link *l, struct tipc_msg *hdr,
1579 			   struct sk_buff_head *xmitq)
1580 {
1581 	u16 peers_snd_nxt = msg_bc_snd_nxt(hdr);
1582 
1583 	if (!link_is_up(l))
1584 		return;
1585 
1586 	if (!msg_peer_node_is_up(hdr))
1587 		return;
1588 
1589 	l->bc_peer_is_up = true;
1590 
1591 	/* Ignore if peers_snd_nxt goes beyond receive window */
1592 	if (more(peers_snd_nxt, l->rcv_nxt + l->window))
1593 		return;
1594 
1595 	if (!more(peers_snd_nxt, l->rcv_nxt)) {
1596 		l->nack_state = BC_NACK_SND_CONDITIONAL;
1597 		return;
1598 	}
1599 
1600 	/* Don't NACK if one was recently sent or peeked */
1601 	if (l->nack_state == BC_NACK_SND_SUPPRESS) {
1602 		l->nack_state = BC_NACK_SND_UNCONDITIONAL;
1603 		return;
1604 	}
1605 
1606 	/* Conditionally delay NACK sending until next synch rcv */
1607 	if (l->nack_state == BC_NACK_SND_CONDITIONAL) {
1608 		l->nack_state = BC_NACK_SND_UNCONDITIONAL;
1609 		if ((peers_snd_nxt - l->rcv_nxt) < TIPC_MIN_LINK_WIN)
1610 			return;
1611 	}
1612 
1613 	/* Send NACK now but suppress next one */
1614 	tipc_link_build_bc_proto_msg(l, true, peers_snd_nxt, xmitq);
1615 	l->nack_state = BC_NACK_SND_SUPPRESS;
1616 }
1617 
1618 void tipc_link_bc_ack_rcv(struct tipc_link *l, u16 acked,
1619 			  struct sk_buff_head *xmitq)
1620 {
1621 	struct sk_buff *skb, *tmp;
1622 	struct tipc_link *snd_l = l->bc_sndlink;
1623 
1624 	if (!link_is_up(l) || !l->bc_peer_is_up)
1625 		return;
1626 
1627 	if (!more(acked, l->acked))
1628 		return;
1629 
1630 	/* Skip over packets peer has already acked */
1631 	skb_queue_walk(&snd_l->transmq, skb) {
1632 		if (more(buf_seqno(skb), l->acked))
1633 			break;
1634 	}
1635 
1636 	/* Update/release the packets peer is acking now */
1637 	skb_queue_walk_from_safe(&snd_l->transmq, skb, tmp) {
1638 		if (more(buf_seqno(skb), acked))
1639 			break;
1640 		if (!--TIPC_SKB_CB(skb)->ackers) {
1641 			__skb_unlink(skb, &snd_l->transmq);
1642 			kfree_skb(skb);
1643 		}
1644 	}
1645 	l->acked = acked;
1646 	tipc_link_advance_backlog(snd_l, xmitq);
1647 	if (unlikely(!skb_queue_empty(&snd_l->wakeupq)))
1648 		link_prepare_wakeup(snd_l);
1649 }
1650 
1651 /* tipc_link_bc_nack_rcv(): receive broadcast nack message
1652  */
1653 int tipc_link_bc_nack_rcv(struct tipc_link *l, struct sk_buff *skb,
1654 			  struct sk_buff_head *xmitq)
1655 {
1656 	struct tipc_msg *hdr = buf_msg(skb);
1657 	u32 dnode = msg_destnode(hdr);
1658 	int mtyp = msg_type(hdr);
1659 	u16 acked = msg_bcast_ack(hdr);
1660 	u16 from = acked + 1;
1661 	u16 to = msg_bcgap_to(hdr);
1662 	u16 peers_snd_nxt = to + 1;
1663 	int rc = 0;
1664 
1665 	kfree_skb(skb);
1666 
1667 	if (!tipc_link_is_up(l) || !l->bc_peer_is_up)
1668 		return 0;
1669 
1670 	if (mtyp != STATE_MSG)
1671 		return 0;
1672 
1673 	if (dnode == link_own_addr(l)) {
1674 		tipc_link_bc_ack_rcv(l, acked, xmitq);
1675 		rc = tipc_link_retrans(l->bc_sndlink, from, to, xmitq);
1676 		l->stats.recv_nacks++;
1677 		return rc;
1678 	}
1679 
1680 	/* Msg for other node => suppress own NACK at next sync if applicable */
1681 	if (more(peers_snd_nxt, l->rcv_nxt) && !less(l->rcv_nxt, from))
1682 		l->nack_state = BC_NACK_SND_SUPPRESS;
1683 
1684 	return 0;
1685 }
1686 
1687 void tipc_link_set_queue_limits(struct tipc_link *l, u32 win)
1688 {
1689 	int max_bulk = TIPC_MAX_PUBLICATIONS / (l->mtu / ITEM_SIZE);
1690 
1691 	l->window = win;
1692 	l->backlog[TIPC_LOW_IMPORTANCE].limit      = win / 2;
1693 	l->backlog[TIPC_MEDIUM_IMPORTANCE].limit   = win;
1694 	l->backlog[TIPC_HIGH_IMPORTANCE].limit     = win / 2 * 3;
1695 	l->backlog[TIPC_CRITICAL_IMPORTANCE].limit = win * 2;
1696 	l->backlog[TIPC_SYSTEM_IMPORTANCE].limit   = max_bulk;
1697 }
1698 
1699 /**
1700  * link_reset_stats - reset link statistics
1701  * @l: pointer to link
1702  */
1703 void tipc_link_reset_stats(struct tipc_link *l)
1704 {
1705 	memset(&l->stats, 0, sizeof(l->stats));
1706 	if (!link_is_bc_sndlink(l)) {
1707 		l->stats.sent_info = l->snd_nxt;
1708 		l->stats.recv_info = l->rcv_nxt;
1709 	}
1710 }
1711 
1712 static void link_print(struct tipc_link *l, const char *str)
1713 {
1714 	struct sk_buff *hskb = skb_peek(&l->transmq);
1715 	u16 head = hskb ? msg_seqno(buf_msg(hskb)) : l->snd_nxt - 1;
1716 	u16 tail = l->snd_nxt - 1;
1717 
1718 	pr_info("%s Link <%s> state %x\n", str, l->name, l->state);
1719 	pr_info("XMTQ: %u [%u-%u], BKLGQ: %u, SNDNX: %u, RCVNX: %u\n",
1720 		skb_queue_len(&l->transmq), head, tail,
1721 		skb_queue_len(&l->backlogq), l->snd_nxt, l->rcv_nxt);
1722 }
1723 
1724 /* Parse and validate nested (link) properties valid for media, bearer and link
1725  */
1726 int tipc_nl_parse_link_prop(struct nlattr *prop, struct nlattr *props[])
1727 {
1728 	int err;
1729 
1730 	err = nla_parse_nested(props, TIPC_NLA_PROP_MAX, prop,
1731 			       tipc_nl_prop_policy);
1732 	if (err)
1733 		return err;
1734 
1735 	if (props[TIPC_NLA_PROP_PRIO]) {
1736 		u32 prio;
1737 
1738 		prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
1739 		if (prio > TIPC_MAX_LINK_PRI)
1740 			return -EINVAL;
1741 	}
1742 
1743 	if (props[TIPC_NLA_PROP_TOL]) {
1744 		u32 tol;
1745 
1746 		tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
1747 		if ((tol < TIPC_MIN_LINK_TOL) || (tol > TIPC_MAX_LINK_TOL))
1748 			return -EINVAL;
1749 	}
1750 
1751 	if (props[TIPC_NLA_PROP_WIN]) {
1752 		u32 win;
1753 
1754 		win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
1755 		if ((win < TIPC_MIN_LINK_WIN) || (win > TIPC_MAX_LINK_WIN))
1756 			return -EINVAL;
1757 	}
1758 
1759 	return 0;
1760 }
1761 
1762 static int __tipc_nl_add_stats(struct sk_buff *skb, struct tipc_stats *s)
1763 {
1764 	int i;
1765 	struct nlattr *stats;
1766 
1767 	struct nla_map {
1768 		u32 key;
1769 		u32 val;
1770 	};
1771 
1772 	struct nla_map map[] = {
1773 		{TIPC_NLA_STATS_RX_INFO, s->recv_info},
1774 		{TIPC_NLA_STATS_RX_FRAGMENTS, s->recv_fragments},
1775 		{TIPC_NLA_STATS_RX_FRAGMENTED, s->recv_fragmented},
1776 		{TIPC_NLA_STATS_RX_BUNDLES, s->recv_bundles},
1777 		{TIPC_NLA_STATS_RX_BUNDLED, s->recv_bundled},
1778 		{TIPC_NLA_STATS_TX_INFO, s->sent_info},
1779 		{TIPC_NLA_STATS_TX_FRAGMENTS, s->sent_fragments},
1780 		{TIPC_NLA_STATS_TX_FRAGMENTED, s->sent_fragmented},
1781 		{TIPC_NLA_STATS_TX_BUNDLES, s->sent_bundles},
1782 		{TIPC_NLA_STATS_TX_BUNDLED, s->sent_bundled},
1783 		{TIPC_NLA_STATS_MSG_PROF_TOT, (s->msg_length_counts) ?
1784 			s->msg_length_counts : 1},
1785 		{TIPC_NLA_STATS_MSG_LEN_CNT, s->msg_length_counts},
1786 		{TIPC_NLA_STATS_MSG_LEN_TOT, s->msg_lengths_total},
1787 		{TIPC_NLA_STATS_MSG_LEN_P0, s->msg_length_profile[0]},
1788 		{TIPC_NLA_STATS_MSG_LEN_P1, s->msg_length_profile[1]},
1789 		{TIPC_NLA_STATS_MSG_LEN_P2, s->msg_length_profile[2]},
1790 		{TIPC_NLA_STATS_MSG_LEN_P3, s->msg_length_profile[3]},
1791 		{TIPC_NLA_STATS_MSG_LEN_P4, s->msg_length_profile[4]},
1792 		{TIPC_NLA_STATS_MSG_LEN_P5, s->msg_length_profile[5]},
1793 		{TIPC_NLA_STATS_MSG_LEN_P6, s->msg_length_profile[6]},
1794 		{TIPC_NLA_STATS_RX_STATES, s->recv_states},
1795 		{TIPC_NLA_STATS_RX_PROBES, s->recv_probes},
1796 		{TIPC_NLA_STATS_RX_NACKS, s->recv_nacks},
1797 		{TIPC_NLA_STATS_RX_DEFERRED, s->deferred_recv},
1798 		{TIPC_NLA_STATS_TX_STATES, s->sent_states},
1799 		{TIPC_NLA_STATS_TX_PROBES, s->sent_probes},
1800 		{TIPC_NLA_STATS_TX_NACKS, s->sent_nacks},
1801 		{TIPC_NLA_STATS_TX_ACKS, s->sent_acks},
1802 		{TIPC_NLA_STATS_RETRANSMITTED, s->retransmitted},
1803 		{TIPC_NLA_STATS_DUPLICATES, s->duplicates},
1804 		{TIPC_NLA_STATS_LINK_CONGS, s->link_congs},
1805 		{TIPC_NLA_STATS_MAX_QUEUE, s->max_queue_sz},
1806 		{TIPC_NLA_STATS_AVG_QUEUE, s->queue_sz_counts ?
1807 			(s->accu_queue_sz / s->queue_sz_counts) : 0}
1808 	};
1809 
1810 	stats = nla_nest_start(skb, TIPC_NLA_LINK_STATS);
1811 	if (!stats)
1812 		return -EMSGSIZE;
1813 
1814 	for (i = 0; i <  ARRAY_SIZE(map); i++)
1815 		if (nla_put_u32(skb, map[i].key, map[i].val))
1816 			goto msg_full;
1817 
1818 	nla_nest_end(skb, stats);
1819 
1820 	return 0;
1821 msg_full:
1822 	nla_nest_cancel(skb, stats);
1823 
1824 	return -EMSGSIZE;
1825 }
1826 
1827 /* Caller should hold appropriate locks to protect the link */
1828 int __tipc_nl_add_link(struct net *net, struct tipc_nl_msg *msg,
1829 		       struct tipc_link *link, int nlflags)
1830 {
1831 	int err;
1832 	void *hdr;
1833 	struct nlattr *attrs;
1834 	struct nlattr *prop;
1835 	struct tipc_net *tn = net_generic(net, tipc_net_id);
1836 
1837 	hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
1838 			  nlflags, TIPC_NL_LINK_GET);
1839 	if (!hdr)
1840 		return -EMSGSIZE;
1841 
1842 	attrs = nla_nest_start(msg->skb, TIPC_NLA_LINK);
1843 	if (!attrs)
1844 		goto msg_full;
1845 
1846 	if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, link->name))
1847 		goto attr_msg_full;
1848 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_DEST,
1849 			tipc_cluster_mask(tn->own_addr)))
1850 		goto attr_msg_full;
1851 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_MTU, link->mtu))
1852 		goto attr_msg_full;
1853 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, link->rcv_nxt))
1854 		goto attr_msg_full;
1855 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, link->snd_nxt))
1856 		goto attr_msg_full;
1857 
1858 	if (tipc_link_is_up(link))
1859 		if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
1860 			goto attr_msg_full;
1861 	if (link->active)
1862 		if (nla_put_flag(msg->skb, TIPC_NLA_LINK_ACTIVE))
1863 			goto attr_msg_full;
1864 
1865 	prop = nla_nest_start(msg->skb, TIPC_NLA_LINK_PROP);
1866 	if (!prop)
1867 		goto attr_msg_full;
1868 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
1869 		goto prop_msg_full;
1870 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_TOL, link->tolerance))
1871 		goto prop_msg_full;
1872 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN,
1873 			link->window))
1874 		goto prop_msg_full;
1875 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
1876 		goto prop_msg_full;
1877 	nla_nest_end(msg->skb, prop);
1878 
1879 	err = __tipc_nl_add_stats(msg->skb, &link->stats);
1880 	if (err)
1881 		goto attr_msg_full;
1882 
1883 	nla_nest_end(msg->skb, attrs);
1884 	genlmsg_end(msg->skb, hdr);
1885 
1886 	return 0;
1887 
1888 prop_msg_full:
1889 	nla_nest_cancel(msg->skb, prop);
1890 attr_msg_full:
1891 	nla_nest_cancel(msg->skb, attrs);
1892 msg_full:
1893 	genlmsg_cancel(msg->skb, hdr);
1894 
1895 	return -EMSGSIZE;
1896 }
1897 
1898 static int __tipc_nl_add_bc_link_stat(struct sk_buff *skb,
1899 				      struct tipc_stats *stats)
1900 {
1901 	int i;
1902 	struct nlattr *nest;
1903 
1904 	struct nla_map {
1905 		__u32 key;
1906 		__u32 val;
1907 	};
1908 
1909 	struct nla_map map[] = {
1910 		{TIPC_NLA_STATS_RX_INFO, stats->recv_info},
1911 		{TIPC_NLA_STATS_RX_FRAGMENTS, stats->recv_fragments},
1912 		{TIPC_NLA_STATS_RX_FRAGMENTED, stats->recv_fragmented},
1913 		{TIPC_NLA_STATS_RX_BUNDLES, stats->recv_bundles},
1914 		{TIPC_NLA_STATS_RX_BUNDLED, stats->recv_bundled},
1915 		{TIPC_NLA_STATS_TX_INFO, stats->sent_info},
1916 		{TIPC_NLA_STATS_TX_FRAGMENTS, stats->sent_fragments},
1917 		{TIPC_NLA_STATS_TX_FRAGMENTED, stats->sent_fragmented},
1918 		{TIPC_NLA_STATS_TX_BUNDLES, stats->sent_bundles},
1919 		{TIPC_NLA_STATS_TX_BUNDLED, stats->sent_bundled},
1920 		{TIPC_NLA_STATS_RX_NACKS, stats->recv_nacks},
1921 		{TIPC_NLA_STATS_RX_DEFERRED, stats->deferred_recv},
1922 		{TIPC_NLA_STATS_TX_NACKS, stats->sent_nacks},
1923 		{TIPC_NLA_STATS_TX_ACKS, stats->sent_acks},
1924 		{TIPC_NLA_STATS_RETRANSMITTED, stats->retransmitted},
1925 		{TIPC_NLA_STATS_DUPLICATES, stats->duplicates},
1926 		{TIPC_NLA_STATS_LINK_CONGS, stats->link_congs},
1927 		{TIPC_NLA_STATS_MAX_QUEUE, stats->max_queue_sz},
1928 		{TIPC_NLA_STATS_AVG_QUEUE, stats->queue_sz_counts ?
1929 			(stats->accu_queue_sz / stats->queue_sz_counts) : 0}
1930 	};
1931 
1932 	nest = nla_nest_start(skb, TIPC_NLA_LINK_STATS);
1933 	if (!nest)
1934 		return -EMSGSIZE;
1935 
1936 	for (i = 0; i <  ARRAY_SIZE(map); i++)
1937 		if (nla_put_u32(skb, map[i].key, map[i].val))
1938 			goto msg_full;
1939 
1940 	nla_nest_end(skb, nest);
1941 
1942 	return 0;
1943 msg_full:
1944 	nla_nest_cancel(skb, nest);
1945 
1946 	return -EMSGSIZE;
1947 }
1948 
1949 int tipc_nl_add_bc_link(struct net *net, struct tipc_nl_msg *msg)
1950 {
1951 	int err;
1952 	void *hdr;
1953 	struct nlattr *attrs;
1954 	struct nlattr *prop;
1955 	struct tipc_net *tn = net_generic(net, tipc_net_id);
1956 	struct tipc_link *bcl = tn->bcl;
1957 
1958 	if (!bcl)
1959 		return 0;
1960 
1961 	tipc_bcast_lock(net);
1962 
1963 	hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
1964 			  NLM_F_MULTI, TIPC_NL_LINK_GET);
1965 	if (!hdr) {
1966 		tipc_bcast_unlock(net);
1967 		return -EMSGSIZE;
1968 	}
1969 
1970 	attrs = nla_nest_start(msg->skb, TIPC_NLA_LINK);
1971 	if (!attrs)
1972 		goto msg_full;
1973 
1974 	/* The broadcast link is always up */
1975 	if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
1976 		goto attr_msg_full;
1977 
1978 	if (nla_put_flag(msg->skb, TIPC_NLA_LINK_BROADCAST))
1979 		goto attr_msg_full;
1980 	if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, bcl->name))
1981 		goto attr_msg_full;
1982 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, bcl->rcv_nxt))
1983 		goto attr_msg_full;
1984 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, bcl->snd_nxt))
1985 		goto attr_msg_full;
1986 
1987 	prop = nla_nest_start(msg->skb, TIPC_NLA_LINK_PROP);
1988 	if (!prop)
1989 		goto attr_msg_full;
1990 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN, bcl->window))
1991 		goto prop_msg_full;
1992 	nla_nest_end(msg->skb, prop);
1993 
1994 	err = __tipc_nl_add_bc_link_stat(msg->skb, &bcl->stats);
1995 	if (err)
1996 		goto attr_msg_full;
1997 
1998 	tipc_bcast_unlock(net);
1999 	nla_nest_end(msg->skb, attrs);
2000 	genlmsg_end(msg->skb, hdr);
2001 
2002 	return 0;
2003 
2004 prop_msg_full:
2005 	nla_nest_cancel(msg->skb, prop);
2006 attr_msg_full:
2007 	nla_nest_cancel(msg->skb, attrs);
2008 msg_full:
2009 	tipc_bcast_unlock(net);
2010 	genlmsg_cancel(msg->skb, hdr);
2011 
2012 	return -EMSGSIZE;
2013 }
2014 
2015 void tipc_link_set_tolerance(struct tipc_link *l, u32 tol,
2016 			     struct sk_buff_head *xmitq)
2017 {
2018 	l->tolerance = tol;
2019 	tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, tol, 0, xmitq);
2020 }
2021 
2022 void tipc_link_set_prio(struct tipc_link *l, u32 prio,
2023 			struct sk_buff_head *xmitq)
2024 {
2025 	l->priority = prio;
2026 	tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, prio, xmitq);
2027 }
2028 
2029 void tipc_link_set_abort_limit(struct tipc_link *l, u32 limit)
2030 {
2031 	l->abort_limit = limit;
2032 }
2033