xref: /openbmc/linux/net/tipc/link.c (revision 6278e03dc667b611cc9ebbd8f455d859f18f8e11)
1 /*
2  * net/tipc/link.c: TIPC link code
3  *
4  * Copyright (c) 1996-2007, 2012-2016, 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  * @abort_limit: # of unacknowledged continuity probes needed to reset link
91  * @state: current state of link FSM
92  * @peer_caps: bitmap describing capabilities of peer node
93  * @silent_intv_cnt: # of timer intervals without any reception from peer
94  * @proto_msg: template for control messages generated by link
95  * @pmsg: convenience pointer to "proto_msg" field
96  * @priority: current link priority
97  * @net_plane: current link network plane ('A' through 'H')
98  * @backlog_limit: backlog queue congestion thresholds (indexed by importance)
99  * @exp_msg_count: # of tunnelled messages expected during link changeover
100  * @reset_rcv_checkpt: seq # of last acknowledged message at time of link reset
101  * @mtu: current maximum packet size for this link
102  * @advertised_mtu: advertised own mtu when link is being established
103  * @transmitq: queue for sent, non-acked messages
104  * @backlogq: queue for messages waiting to be sent
105  * @snt_nxt: next sequence number to use for outbound messages
106  * @last_retransmitted: sequence number of most recently retransmitted message
107  * @stale_count: # of identical retransmit requests made by peer
108  * @ackers: # of peers that needs to ack each packet before it can be released
109  * @acked: # last packet acked by a certain peer. Used for broadcast.
110  * @rcv_nxt: next sequence number to expect for inbound messages
111  * @deferred_queue: deferred queue saved OOS b'cast message received from node
112  * @unacked_window: # of inbound messages rx'd without ack'ing back to peer
113  * @inputq: buffer queue for messages to be delivered upwards
114  * @namedq: buffer queue for name table messages to be delivered upwards
115  * @next_out: ptr to first unsent outbound message in queue
116  * @wakeupq: linked list of wakeup msgs waiting for link congestion to abate
117  * @long_msg_seq_no: next identifier to use for outbound fragmented messages
118  * @reasm_buf: head of partially reassembled inbound message fragments
119  * @bc_rcvr: marks that this is a broadcast receiver link
120  * @stats: collects statistics regarding link activity
121  */
122 struct tipc_link {
123 	u32 addr;
124 	char name[TIPC_MAX_LINK_NAME];
125 	struct net *net;
126 
127 	/* Management and link supervision data */
128 	u32 peer_session;
129 	u32 session;
130 	u32 peer_bearer_id;
131 	u32 bearer_id;
132 	u32 tolerance;
133 	u32 abort_limit;
134 	u32 state;
135 	u16 peer_caps;
136 	bool active;
137 	u32 silent_intv_cnt;
138 	char if_name[TIPC_MAX_IF_NAME];
139 	u32 priority;
140 	char net_plane;
141 	u16 rst_cnt;
142 
143 	/* Failover/synch */
144 	u16 drop_point;
145 	struct sk_buff *failover_reasm_skb;
146 
147 	/* Max packet negotiation */
148 	u16 mtu;
149 	u16 advertised_mtu;
150 
151 	/* Sending */
152 	struct sk_buff_head transmq;
153 	struct sk_buff_head backlogq;
154 	struct {
155 		u16 len;
156 		u16 limit;
157 	} backlog[5];
158 	u16 snd_nxt;
159 	u16 last_retransm;
160 	u16 window;
161 	u32 stale_count;
162 
163 	/* Reception */
164 	u16 rcv_nxt;
165 	u32 rcv_unacked;
166 	struct sk_buff_head deferdq;
167 	struct sk_buff_head *inputq;
168 	struct sk_buff_head *namedq;
169 
170 	/* Congestion handling */
171 	struct sk_buff_head wakeupq;
172 
173 	/* Fragmentation/reassembly */
174 	struct sk_buff *reasm_buf;
175 
176 	/* Broadcast */
177 	u16 ackers;
178 	u16 acked;
179 	struct tipc_link *bc_rcvlink;
180 	struct tipc_link *bc_sndlink;
181 	int nack_state;
182 	bool bc_peer_is_up;
183 
184 	/* Statistics */
185 	struct tipc_stats stats;
186 };
187 
188 /*
189  * Error message prefixes
190  */
191 static const char *link_co_err = "Link tunneling error, ";
192 static const char *link_rst_msg = "Resetting link ";
193 
194 /* Send states for broadcast NACKs
195  */
196 enum {
197 	BC_NACK_SND_CONDITIONAL,
198 	BC_NACK_SND_UNCONDITIONAL,
199 	BC_NACK_SND_SUPPRESS,
200 };
201 
202 /*
203  * Interval between NACKs when packets arrive out of order
204  */
205 #define TIPC_NACK_INTV (TIPC_MIN_LINK_WIN * 2)
206 
207 /* Wildcard value for link session numbers. When it is known that
208  * peer endpoint is down, any session number must be accepted.
209  */
210 #define ANY_SESSION 0x10000
211 
212 /* Link FSM states:
213  */
214 enum {
215 	LINK_ESTABLISHED     = 0xe,
216 	LINK_ESTABLISHING    = 0xe  << 4,
217 	LINK_RESET           = 0x1  << 8,
218 	LINK_RESETTING       = 0x2  << 12,
219 	LINK_PEER_RESET      = 0xd  << 16,
220 	LINK_FAILINGOVER     = 0xf  << 20,
221 	LINK_SYNCHING        = 0xc  << 24
222 };
223 
224 /* Link FSM state checking routines
225  */
226 static int link_is_up(struct tipc_link *l)
227 {
228 	return l->state & (LINK_ESTABLISHED | LINK_SYNCHING);
229 }
230 
231 static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
232 			       struct sk_buff_head *xmitq);
233 static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
234 				      u16 rcvgap, int tolerance, int priority,
235 				      struct sk_buff_head *xmitq);
236 static void link_print(struct tipc_link *l, const char *str);
237 static void tipc_link_build_nack_msg(struct tipc_link *l,
238 				     struct sk_buff_head *xmitq);
239 static void tipc_link_build_bc_init_msg(struct tipc_link *l,
240 					struct sk_buff_head *xmitq);
241 static bool tipc_link_release_pkts(struct tipc_link *l, u16 to);
242 
243 /*
244  *  Simple non-static link routines (i.e. referenced outside this file)
245  */
246 bool tipc_link_is_up(struct tipc_link *l)
247 {
248 	return link_is_up(l);
249 }
250 
251 bool tipc_link_peer_is_down(struct tipc_link *l)
252 {
253 	return l->state == LINK_PEER_RESET;
254 }
255 
256 bool tipc_link_is_reset(struct tipc_link *l)
257 {
258 	return l->state & (LINK_RESET | LINK_FAILINGOVER | LINK_ESTABLISHING);
259 }
260 
261 bool tipc_link_is_establishing(struct tipc_link *l)
262 {
263 	return l->state == LINK_ESTABLISHING;
264 }
265 
266 bool tipc_link_is_synching(struct tipc_link *l)
267 {
268 	return l->state == LINK_SYNCHING;
269 }
270 
271 bool tipc_link_is_failingover(struct tipc_link *l)
272 {
273 	return l->state == LINK_FAILINGOVER;
274 }
275 
276 bool tipc_link_is_blocked(struct tipc_link *l)
277 {
278 	return l->state & (LINK_RESETTING | LINK_PEER_RESET | LINK_FAILINGOVER);
279 }
280 
281 static bool link_is_bc_sndlink(struct tipc_link *l)
282 {
283 	return !l->bc_sndlink;
284 }
285 
286 static bool link_is_bc_rcvlink(struct tipc_link *l)
287 {
288 	return ((l->bc_rcvlink == l) && !link_is_bc_sndlink(l));
289 }
290 
291 int tipc_link_is_active(struct tipc_link *l)
292 {
293 	return l->active;
294 }
295 
296 void tipc_link_set_active(struct tipc_link *l, bool active)
297 {
298 	l->active = active;
299 }
300 
301 u32 tipc_link_id(struct tipc_link *l)
302 {
303 	return l->peer_bearer_id << 16 | l->bearer_id;
304 }
305 
306 int tipc_link_window(struct tipc_link *l)
307 {
308 	return l->window;
309 }
310 
311 int tipc_link_prio(struct tipc_link *l)
312 {
313 	return l->priority;
314 }
315 
316 unsigned long tipc_link_tolerance(struct tipc_link *l)
317 {
318 	return l->tolerance;
319 }
320 
321 struct sk_buff_head *tipc_link_inputq(struct tipc_link *l)
322 {
323 	return l->inputq;
324 }
325 
326 char tipc_link_plane(struct tipc_link *l)
327 {
328 	return l->net_plane;
329 }
330 
331 void tipc_link_add_bc_peer(struct tipc_link *snd_l,
332 			   struct tipc_link *uc_l,
333 			   struct sk_buff_head *xmitq)
334 {
335 	struct tipc_link *rcv_l = uc_l->bc_rcvlink;
336 
337 	snd_l->ackers++;
338 	rcv_l->acked = snd_l->snd_nxt - 1;
339 	snd_l->state = LINK_ESTABLISHED;
340 	tipc_link_build_bc_init_msg(uc_l, xmitq);
341 }
342 
343 void tipc_link_remove_bc_peer(struct tipc_link *snd_l,
344 			      struct tipc_link *rcv_l,
345 			      struct sk_buff_head *xmitq)
346 {
347 	u16 ack = snd_l->snd_nxt - 1;
348 
349 	snd_l->ackers--;
350 	tipc_link_bc_ack_rcv(rcv_l, ack, xmitq);
351 	tipc_link_reset(rcv_l);
352 	rcv_l->state = LINK_RESET;
353 	if (!snd_l->ackers) {
354 		tipc_link_reset(snd_l);
355 		snd_l->state = LINK_RESET;
356 		__skb_queue_purge(xmitq);
357 	}
358 }
359 
360 int tipc_link_bc_peers(struct tipc_link *l)
361 {
362 	return l->ackers;
363 }
364 
365 void tipc_link_set_mtu(struct tipc_link *l, int mtu)
366 {
367 	l->mtu = mtu;
368 }
369 
370 int tipc_link_mtu(struct tipc_link *l)
371 {
372 	return l->mtu;
373 }
374 
375 u16 tipc_link_rcv_nxt(struct tipc_link *l)
376 {
377 	return l->rcv_nxt;
378 }
379 
380 u16 tipc_link_acked(struct tipc_link *l)
381 {
382 	return l->acked;
383 }
384 
385 char *tipc_link_name(struct tipc_link *l)
386 {
387 	return l->name;
388 }
389 
390 /**
391  * tipc_link_create - create a new link
392  * @n: pointer to associated node
393  * @if_name: associated interface name
394  * @bearer_id: id (index) of associated bearer
395  * @tolerance: link tolerance to be used by link
396  * @net_plane: network plane (A,B,c..) this link belongs to
397  * @mtu: mtu to be advertised by link
398  * @priority: priority to be used by link
399  * @window: send window to be used by link
400  * @session: session to be used by link
401  * @ownnode: identity of own node
402  * @peer: node id of peer node
403  * @peer_caps: bitmap describing peer node capabilities
404  * @bc_sndlink: the namespace global link used for broadcast sending
405  * @bc_rcvlink: the peer specific link used for broadcast reception
406  * @inputq: queue to put messages ready for delivery
407  * @namedq: queue to put binding table update messages ready for delivery
408  * @link: return value, pointer to put the created link
409  *
410  * Returns true if link was created, otherwise false
411  */
412 bool tipc_link_create(struct net *net, char *if_name, int bearer_id,
413 		      int tolerance, char net_plane, u32 mtu, int priority,
414 		      int window, u32 session, u32 ownnode, u32 peer,
415 		      u16 peer_caps,
416 		      struct tipc_link *bc_sndlink,
417 		      struct tipc_link *bc_rcvlink,
418 		      struct sk_buff_head *inputq,
419 		      struct sk_buff_head *namedq,
420 		      struct tipc_link **link)
421 {
422 	struct tipc_link *l;
423 
424 	l = kzalloc(sizeof(*l), GFP_ATOMIC);
425 	if (!l)
426 		return false;
427 	*link = l;
428 	l->session = session;
429 
430 	/* Note: peer i/f name is completed by reset/activate message */
431 	sprintf(l->name, "%u.%u.%u:%s-%u.%u.%u:unknown",
432 		tipc_zone(ownnode), tipc_cluster(ownnode), tipc_node(ownnode),
433 		if_name, tipc_zone(peer), tipc_cluster(peer), tipc_node(peer));
434 	strcpy(l->if_name, if_name);
435 	l->addr = peer;
436 	l->peer_caps = peer_caps;
437 	l->net = net;
438 	l->peer_session = ANY_SESSION;
439 	l->bearer_id = bearer_id;
440 	l->tolerance = tolerance;
441 	l->net_plane = net_plane;
442 	l->advertised_mtu = mtu;
443 	l->mtu = mtu;
444 	l->priority = priority;
445 	tipc_link_set_queue_limits(l, window);
446 	l->ackers = 1;
447 	l->bc_sndlink = bc_sndlink;
448 	l->bc_rcvlink = bc_rcvlink;
449 	l->inputq = inputq;
450 	l->namedq = namedq;
451 	l->state = LINK_RESETTING;
452 	__skb_queue_head_init(&l->transmq);
453 	__skb_queue_head_init(&l->backlogq);
454 	__skb_queue_head_init(&l->deferdq);
455 	skb_queue_head_init(&l->wakeupq);
456 	skb_queue_head_init(l->inputq);
457 	return true;
458 }
459 
460 /**
461  * tipc_link_bc_create - create new link to be used for broadcast
462  * @n: pointer to associated node
463  * @mtu: mtu to be used
464  * @window: send window to be used
465  * @inputq: queue to put messages ready for delivery
466  * @namedq: queue to put binding table update messages ready for delivery
467  * @link: return value, pointer to put the created link
468  *
469  * Returns true if link was created, otherwise false
470  */
471 bool tipc_link_bc_create(struct net *net, u32 ownnode, u32 peer,
472 			 int mtu, int window, u16 peer_caps,
473 			 struct sk_buff_head *inputq,
474 			 struct sk_buff_head *namedq,
475 			 struct tipc_link *bc_sndlink,
476 			 struct tipc_link **link)
477 {
478 	struct tipc_link *l;
479 
480 	if (!tipc_link_create(net, "", MAX_BEARERS, 0, 'Z', mtu, 0, window,
481 			      0, ownnode, peer, peer_caps, bc_sndlink,
482 			      NULL, inputq, namedq, link))
483 		return false;
484 
485 	l = *link;
486 	strcpy(l->name, tipc_bclink_name);
487 	tipc_link_reset(l);
488 	l->state = LINK_RESET;
489 	l->ackers = 0;
490 	l->bc_rcvlink = l;
491 
492 	/* Broadcast send link is always up */
493 	if (link_is_bc_sndlink(l))
494 		l->state = LINK_ESTABLISHED;
495 
496 	return true;
497 }
498 
499 /**
500  * tipc_link_fsm_evt - link finite state machine
501  * @l: pointer to link
502  * @evt: state machine event to be processed
503  */
504 int tipc_link_fsm_evt(struct tipc_link *l, int evt)
505 {
506 	int rc = 0;
507 
508 	switch (l->state) {
509 	case LINK_RESETTING:
510 		switch (evt) {
511 		case LINK_PEER_RESET_EVT:
512 			l->state = LINK_PEER_RESET;
513 			break;
514 		case LINK_RESET_EVT:
515 			l->state = LINK_RESET;
516 			break;
517 		case LINK_FAILURE_EVT:
518 		case LINK_FAILOVER_BEGIN_EVT:
519 		case LINK_ESTABLISH_EVT:
520 		case LINK_FAILOVER_END_EVT:
521 		case LINK_SYNCH_BEGIN_EVT:
522 		case LINK_SYNCH_END_EVT:
523 		default:
524 			goto illegal_evt;
525 		}
526 		break;
527 	case LINK_RESET:
528 		switch (evt) {
529 		case LINK_PEER_RESET_EVT:
530 			l->state = LINK_ESTABLISHING;
531 			break;
532 		case LINK_FAILOVER_BEGIN_EVT:
533 			l->state = LINK_FAILINGOVER;
534 		case LINK_FAILURE_EVT:
535 		case LINK_RESET_EVT:
536 		case LINK_ESTABLISH_EVT:
537 		case LINK_FAILOVER_END_EVT:
538 			break;
539 		case LINK_SYNCH_BEGIN_EVT:
540 		case LINK_SYNCH_END_EVT:
541 		default:
542 			goto illegal_evt;
543 		}
544 		break;
545 	case LINK_PEER_RESET:
546 		switch (evt) {
547 		case LINK_RESET_EVT:
548 			l->state = LINK_ESTABLISHING;
549 			break;
550 		case LINK_PEER_RESET_EVT:
551 		case LINK_ESTABLISH_EVT:
552 		case LINK_FAILURE_EVT:
553 			break;
554 		case LINK_SYNCH_BEGIN_EVT:
555 		case LINK_SYNCH_END_EVT:
556 		case LINK_FAILOVER_BEGIN_EVT:
557 		case LINK_FAILOVER_END_EVT:
558 		default:
559 			goto illegal_evt;
560 		}
561 		break;
562 	case LINK_FAILINGOVER:
563 		switch (evt) {
564 		case LINK_FAILOVER_END_EVT:
565 			l->state = LINK_RESET;
566 			break;
567 		case LINK_PEER_RESET_EVT:
568 		case LINK_RESET_EVT:
569 		case LINK_ESTABLISH_EVT:
570 		case LINK_FAILURE_EVT:
571 			break;
572 		case LINK_FAILOVER_BEGIN_EVT:
573 		case LINK_SYNCH_BEGIN_EVT:
574 		case LINK_SYNCH_END_EVT:
575 		default:
576 			goto illegal_evt;
577 		}
578 		break;
579 	case LINK_ESTABLISHING:
580 		switch (evt) {
581 		case LINK_ESTABLISH_EVT:
582 			l->state = LINK_ESTABLISHED;
583 			break;
584 		case LINK_FAILOVER_BEGIN_EVT:
585 			l->state = LINK_FAILINGOVER;
586 			break;
587 		case LINK_RESET_EVT:
588 			l->state = LINK_RESET;
589 			break;
590 		case LINK_FAILURE_EVT:
591 		case LINK_PEER_RESET_EVT:
592 		case LINK_SYNCH_BEGIN_EVT:
593 		case LINK_FAILOVER_END_EVT:
594 			break;
595 		case LINK_SYNCH_END_EVT:
596 		default:
597 			goto illegal_evt;
598 		}
599 		break;
600 	case LINK_ESTABLISHED:
601 		switch (evt) {
602 		case LINK_PEER_RESET_EVT:
603 			l->state = LINK_PEER_RESET;
604 			rc |= TIPC_LINK_DOWN_EVT;
605 			break;
606 		case LINK_FAILURE_EVT:
607 			l->state = LINK_RESETTING;
608 			rc |= TIPC_LINK_DOWN_EVT;
609 			break;
610 		case LINK_RESET_EVT:
611 			l->state = LINK_RESET;
612 			break;
613 		case LINK_ESTABLISH_EVT:
614 		case LINK_SYNCH_END_EVT:
615 			break;
616 		case LINK_SYNCH_BEGIN_EVT:
617 			l->state = LINK_SYNCHING;
618 			break;
619 		case LINK_FAILOVER_BEGIN_EVT:
620 		case LINK_FAILOVER_END_EVT:
621 		default:
622 			goto illegal_evt;
623 		}
624 		break;
625 	case LINK_SYNCHING:
626 		switch (evt) {
627 		case LINK_PEER_RESET_EVT:
628 			l->state = LINK_PEER_RESET;
629 			rc |= TIPC_LINK_DOWN_EVT;
630 			break;
631 		case LINK_FAILURE_EVT:
632 			l->state = LINK_RESETTING;
633 			rc |= TIPC_LINK_DOWN_EVT;
634 			break;
635 		case LINK_RESET_EVT:
636 			l->state = LINK_RESET;
637 			break;
638 		case LINK_ESTABLISH_EVT:
639 		case LINK_SYNCH_BEGIN_EVT:
640 			break;
641 		case LINK_SYNCH_END_EVT:
642 			l->state = LINK_ESTABLISHED;
643 			break;
644 		case LINK_FAILOVER_BEGIN_EVT:
645 		case LINK_FAILOVER_END_EVT:
646 		default:
647 			goto illegal_evt;
648 		}
649 		break;
650 	default:
651 		pr_err("Unknown FSM state %x in %s\n", l->state, l->name);
652 	}
653 	return rc;
654 illegal_evt:
655 	pr_err("Illegal FSM event %x in state %x on link %s\n",
656 	       evt, l->state, l->name);
657 	return rc;
658 }
659 
660 /* link_profile_stats - update statistical profiling of traffic
661  */
662 static void link_profile_stats(struct tipc_link *l)
663 {
664 	struct sk_buff *skb;
665 	struct tipc_msg *msg;
666 	int length;
667 
668 	/* Update counters used in statistical profiling of send traffic */
669 	l->stats.accu_queue_sz += skb_queue_len(&l->transmq);
670 	l->stats.queue_sz_counts++;
671 
672 	skb = skb_peek(&l->transmq);
673 	if (!skb)
674 		return;
675 	msg = buf_msg(skb);
676 	length = msg_size(msg);
677 
678 	if (msg_user(msg) == MSG_FRAGMENTER) {
679 		if (msg_type(msg) != FIRST_FRAGMENT)
680 			return;
681 		length = msg_size(msg_get_wrapped(msg));
682 	}
683 	l->stats.msg_lengths_total += length;
684 	l->stats.msg_length_counts++;
685 	if (length <= 64)
686 		l->stats.msg_length_profile[0]++;
687 	else if (length <= 256)
688 		l->stats.msg_length_profile[1]++;
689 	else if (length <= 1024)
690 		l->stats.msg_length_profile[2]++;
691 	else if (length <= 4096)
692 		l->stats.msg_length_profile[3]++;
693 	else if (length <= 16384)
694 		l->stats.msg_length_profile[4]++;
695 	else if (length <= 32768)
696 		l->stats.msg_length_profile[5]++;
697 	else
698 		l->stats.msg_length_profile[6]++;
699 }
700 
701 /* tipc_link_timeout - perform periodic task as instructed from node timeout
702  */
703 int tipc_link_timeout(struct tipc_link *l, struct sk_buff_head *xmitq)
704 {
705 	int mtyp, rc = 0;
706 	bool state = false;
707 	bool probe = false;
708 	bool setup = false;
709 	u16 bc_snt = l->bc_sndlink->snd_nxt - 1;
710 	u16 bc_acked = l->bc_rcvlink->acked;
711 
712 	link_profile_stats(l);
713 
714 	switch (l->state) {
715 	case LINK_ESTABLISHED:
716 	case LINK_SYNCHING:
717 		if (l->silent_intv_cnt > l->abort_limit)
718 			return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
719 		mtyp = STATE_MSG;
720 		state = bc_acked != bc_snt;
721 		probe = l->silent_intv_cnt;
722 		l->silent_intv_cnt++;
723 		break;
724 	case LINK_RESET:
725 		setup = l->rst_cnt++ <= 4;
726 		setup |= !(l->rst_cnt % 16);
727 		mtyp = RESET_MSG;
728 		break;
729 	case LINK_ESTABLISHING:
730 		setup = true;
731 		mtyp = ACTIVATE_MSG;
732 		break;
733 	case LINK_PEER_RESET:
734 	case LINK_RESETTING:
735 	case LINK_FAILINGOVER:
736 		break;
737 	default:
738 		break;
739 	}
740 
741 	if (state || probe || setup)
742 		tipc_link_build_proto_msg(l, mtyp, probe, 0, 0, 0, xmitq);
743 
744 	return rc;
745 }
746 
747 /**
748  * link_schedule_user - schedule a message sender for wakeup after congestion
749  * @link: congested link
750  * @list: message that was attempted sent
751  * Create pseudo msg to send back to user when congestion abates
752  * Does not consume buffer list
753  */
754 static int link_schedule_user(struct tipc_link *link, struct sk_buff_head *list)
755 {
756 	struct tipc_msg *msg = buf_msg(skb_peek(list));
757 	int imp = msg_importance(msg);
758 	u32 oport = msg_origport(msg);
759 	u32 addr = tipc_own_addr(link->net);
760 	struct sk_buff *skb;
761 
762 	/* This really cannot happen...  */
763 	if (unlikely(imp > TIPC_CRITICAL_IMPORTANCE)) {
764 		pr_warn("%s<%s>, send queue full", link_rst_msg, link->name);
765 		return -ENOBUFS;
766 	}
767 	/* Non-blocking sender: */
768 	if (TIPC_SKB_CB(skb_peek(list))->wakeup_pending)
769 		return -ELINKCONG;
770 
771 	/* Create and schedule wakeup pseudo message */
772 	skb = tipc_msg_create(SOCK_WAKEUP, 0, INT_H_SIZE, 0,
773 			      addr, addr, oport, 0, 0);
774 	if (!skb)
775 		return -ENOBUFS;
776 	TIPC_SKB_CB(skb)->chain_sz = skb_queue_len(list);
777 	TIPC_SKB_CB(skb)->chain_imp = imp;
778 	skb_queue_tail(&link->wakeupq, skb);
779 	link->stats.link_congs++;
780 	return -ELINKCONG;
781 }
782 
783 /**
784  * link_prepare_wakeup - prepare users for wakeup after congestion
785  * @link: congested link
786  * Move a number of waiting users, as permitted by available space in
787  * the send queue, from link wait queue to node wait queue for wakeup
788  */
789 void link_prepare_wakeup(struct tipc_link *l)
790 {
791 	int pnd[TIPC_SYSTEM_IMPORTANCE + 1] = {0,};
792 	int imp, lim;
793 	struct sk_buff *skb, *tmp;
794 
795 	skb_queue_walk_safe(&l->wakeupq, skb, tmp) {
796 		imp = TIPC_SKB_CB(skb)->chain_imp;
797 		lim = l->window + l->backlog[imp].limit;
798 		pnd[imp] += TIPC_SKB_CB(skb)->chain_sz;
799 		if ((pnd[imp] + l->backlog[imp].len) >= lim)
800 			break;
801 		skb_unlink(skb, &l->wakeupq);
802 		skb_queue_tail(l->inputq, skb);
803 	}
804 }
805 
806 void tipc_link_reset(struct tipc_link *l)
807 {
808 	l->peer_session = ANY_SESSION;
809 	l->session++;
810 	l->mtu = l->advertised_mtu;
811 	__skb_queue_purge(&l->transmq);
812 	__skb_queue_purge(&l->deferdq);
813 	skb_queue_splice_init(&l->wakeupq, l->inputq);
814 	__skb_queue_purge(&l->backlogq);
815 	l->backlog[TIPC_LOW_IMPORTANCE].len = 0;
816 	l->backlog[TIPC_MEDIUM_IMPORTANCE].len = 0;
817 	l->backlog[TIPC_HIGH_IMPORTANCE].len = 0;
818 	l->backlog[TIPC_CRITICAL_IMPORTANCE].len = 0;
819 	l->backlog[TIPC_SYSTEM_IMPORTANCE].len = 0;
820 	kfree_skb(l->reasm_buf);
821 	kfree_skb(l->failover_reasm_skb);
822 	l->reasm_buf = NULL;
823 	l->failover_reasm_skb = NULL;
824 	l->rcv_unacked = 0;
825 	l->snd_nxt = 1;
826 	l->rcv_nxt = 1;
827 	l->acked = 0;
828 	l->silent_intv_cnt = 0;
829 	l->rst_cnt = 0;
830 	l->stats.recv_info = 0;
831 	l->stale_count = 0;
832 	l->bc_peer_is_up = false;
833 	tipc_link_reset_stats(l);
834 }
835 
836 /**
837  * tipc_link_xmit(): enqueue buffer list according to queue situation
838  * @link: link to use
839  * @list: chain of buffers containing message
840  * @xmitq: returned list of packets to be sent by caller
841  *
842  * Consumes the buffer chain, except when returning -ELINKCONG,
843  * since the caller then may want to make more send attempts.
844  * Returns 0 if success, or errno: -ELINKCONG, -EMSGSIZE or -ENOBUFS
845  * Messages at TIPC_SYSTEM_IMPORTANCE are always accepted
846  */
847 int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *list,
848 		   struct sk_buff_head *xmitq)
849 {
850 	struct tipc_msg *hdr = buf_msg(skb_peek(list));
851 	unsigned int maxwin = l->window;
852 	unsigned int i, imp = msg_importance(hdr);
853 	unsigned int mtu = l->mtu;
854 	u16 ack = l->rcv_nxt - 1;
855 	u16 seqno = l->snd_nxt;
856 	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
857 	struct sk_buff_head *transmq = &l->transmq;
858 	struct sk_buff_head *backlogq = &l->backlogq;
859 	struct sk_buff *skb, *_skb, *bskb;
860 
861 	/* Match msg importance against this and all higher backlog limits: */
862 	for (i = imp; i <= TIPC_SYSTEM_IMPORTANCE; i++) {
863 		if (unlikely(l->backlog[i].len >= l->backlog[i].limit))
864 			return link_schedule_user(l, list);
865 	}
866 	if (unlikely(msg_size(hdr) > mtu)) {
867 		skb_queue_purge(list);
868 		return -EMSGSIZE;
869 	}
870 
871 	/* Prepare each packet for sending, and add to relevant queue: */
872 	while (skb_queue_len(list)) {
873 		skb = skb_peek(list);
874 		hdr = buf_msg(skb);
875 		msg_set_seqno(hdr, seqno);
876 		msg_set_ack(hdr, ack);
877 		msg_set_bcast_ack(hdr, bc_ack);
878 
879 		if (likely(skb_queue_len(transmq) < maxwin)) {
880 			_skb = skb_clone(skb, GFP_ATOMIC);
881 			if (!_skb) {
882 				skb_queue_purge(list);
883 				return -ENOBUFS;
884 			}
885 			__skb_dequeue(list);
886 			__skb_queue_tail(transmq, skb);
887 			__skb_queue_tail(xmitq, _skb);
888 			TIPC_SKB_CB(skb)->ackers = l->ackers;
889 			l->rcv_unacked = 0;
890 			seqno++;
891 			continue;
892 		}
893 		if (tipc_msg_bundle(skb_peek_tail(backlogq), hdr, mtu)) {
894 			kfree_skb(__skb_dequeue(list));
895 			l->stats.sent_bundled++;
896 			continue;
897 		}
898 		if (tipc_msg_make_bundle(&bskb, hdr, mtu, l->addr)) {
899 			kfree_skb(__skb_dequeue(list));
900 			__skb_queue_tail(backlogq, bskb);
901 			l->backlog[msg_importance(buf_msg(bskb))].len++;
902 			l->stats.sent_bundled++;
903 			l->stats.sent_bundles++;
904 			continue;
905 		}
906 		l->backlog[imp].len += skb_queue_len(list);
907 		skb_queue_splice_tail_init(list, backlogq);
908 	}
909 	l->snd_nxt = seqno;
910 	return 0;
911 }
912 
913 void tipc_link_advance_backlog(struct tipc_link *l, struct sk_buff_head *xmitq)
914 {
915 	struct sk_buff *skb, *_skb;
916 	struct tipc_msg *hdr;
917 	u16 seqno = l->snd_nxt;
918 	u16 ack = l->rcv_nxt - 1;
919 	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
920 
921 	while (skb_queue_len(&l->transmq) < l->window) {
922 		skb = skb_peek(&l->backlogq);
923 		if (!skb)
924 			break;
925 		_skb = skb_clone(skb, GFP_ATOMIC);
926 		if (!_skb)
927 			break;
928 		__skb_dequeue(&l->backlogq);
929 		hdr = buf_msg(skb);
930 		l->backlog[msg_importance(hdr)].len--;
931 		__skb_queue_tail(&l->transmq, skb);
932 		__skb_queue_tail(xmitq, _skb);
933 		TIPC_SKB_CB(skb)->ackers = l->ackers;
934 		msg_set_seqno(hdr, seqno);
935 		msg_set_ack(hdr, ack);
936 		msg_set_bcast_ack(hdr, bc_ack);
937 		l->rcv_unacked = 0;
938 		seqno++;
939 	}
940 	l->snd_nxt = seqno;
941 }
942 
943 static void link_retransmit_failure(struct tipc_link *l, struct sk_buff *skb)
944 {
945 	struct tipc_msg *hdr = buf_msg(skb);
946 
947 	pr_warn("Retransmission failure on link <%s>\n", l->name);
948 	link_print(l, "Resetting link ");
949 	pr_info("Failed msg: usr %u, typ %u, len %u, err %u\n",
950 		msg_user(hdr), msg_type(hdr), msg_size(hdr), msg_errcode(hdr));
951 	pr_info("sqno %u, prev: %x, src: %x\n",
952 		msg_seqno(hdr), msg_prevnode(hdr), msg_orignode(hdr));
953 }
954 
955 int tipc_link_retrans(struct tipc_link *l, u16 from, u16 to,
956 		      struct sk_buff_head *xmitq)
957 {
958 	struct sk_buff *_skb, *skb = skb_peek(&l->transmq);
959 	struct tipc_msg *hdr;
960 	u16 ack = l->rcv_nxt - 1;
961 	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
962 
963 	if (!skb)
964 		return 0;
965 
966 	/* Detect repeated retransmit failures on same packet */
967 	if (likely(l->last_retransm != buf_seqno(skb))) {
968 		l->last_retransm = buf_seqno(skb);
969 		l->stale_count = 1;
970 	} else if (++l->stale_count > 100) {
971 		link_retransmit_failure(l, skb);
972 		return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
973 	}
974 
975 	/* Move forward to where retransmission should start */
976 	skb_queue_walk(&l->transmq, skb) {
977 		if (!less(buf_seqno(skb), from))
978 			break;
979 	}
980 
981 	skb_queue_walk_from(&l->transmq, skb) {
982 		if (more(buf_seqno(skb), to))
983 			break;
984 		hdr = buf_msg(skb);
985 		_skb = __pskb_copy(skb, MIN_H_SIZE, GFP_ATOMIC);
986 		if (!_skb)
987 			return 0;
988 		hdr = buf_msg(_skb);
989 		msg_set_ack(hdr, ack);
990 		msg_set_bcast_ack(hdr, bc_ack);
991 		_skb->priority = TC_PRIO_CONTROL;
992 		__skb_queue_tail(xmitq, _skb);
993 		l->stats.retransmitted++;
994 	}
995 	return 0;
996 }
997 
998 /* tipc_data_input - deliver data and name distr msgs to upper layer
999  *
1000  * Consumes buffer if message is of right type
1001  * Node lock must be held
1002  */
1003 static bool tipc_data_input(struct tipc_link *l, struct sk_buff *skb,
1004 			    struct sk_buff_head *inputq)
1005 {
1006 	switch (msg_user(buf_msg(skb))) {
1007 	case TIPC_LOW_IMPORTANCE:
1008 	case TIPC_MEDIUM_IMPORTANCE:
1009 	case TIPC_HIGH_IMPORTANCE:
1010 	case TIPC_CRITICAL_IMPORTANCE:
1011 	case CONN_MANAGER:
1012 		skb_queue_tail(inputq, skb);
1013 		return true;
1014 	case NAME_DISTRIBUTOR:
1015 		l->bc_rcvlink->state = LINK_ESTABLISHED;
1016 		skb_queue_tail(l->namedq, skb);
1017 		return true;
1018 	case MSG_BUNDLER:
1019 	case TUNNEL_PROTOCOL:
1020 	case MSG_FRAGMENTER:
1021 	case BCAST_PROTOCOL:
1022 		return false;
1023 	default:
1024 		pr_warn("Dropping received illegal msg type\n");
1025 		kfree_skb(skb);
1026 		return false;
1027 	};
1028 }
1029 
1030 /* tipc_link_input - process packet that has passed link protocol check
1031  *
1032  * Consumes buffer
1033  */
1034 static int tipc_link_input(struct tipc_link *l, struct sk_buff *skb,
1035 			   struct sk_buff_head *inputq)
1036 {
1037 	struct tipc_msg *hdr = buf_msg(skb);
1038 	struct sk_buff **reasm_skb = &l->reasm_buf;
1039 	struct sk_buff *iskb;
1040 	struct sk_buff_head tmpq;
1041 	int usr = msg_user(hdr);
1042 	int rc = 0;
1043 	int pos = 0;
1044 	int ipos = 0;
1045 
1046 	if (unlikely(usr == TUNNEL_PROTOCOL)) {
1047 		if (msg_type(hdr) == SYNCH_MSG) {
1048 			__skb_queue_purge(&l->deferdq);
1049 			goto drop;
1050 		}
1051 		if (!tipc_msg_extract(skb, &iskb, &ipos))
1052 			return rc;
1053 		kfree_skb(skb);
1054 		skb = iskb;
1055 		hdr = buf_msg(skb);
1056 		if (less(msg_seqno(hdr), l->drop_point))
1057 			goto drop;
1058 		if (tipc_data_input(l, skb, inputq))
1059 			return rc;
1060 		usr = msg_user(hdr);
1061 		reasm_skb = &l->failover_reasm_skb;
1062 	}
1063 
1064 	if (usr == MSG_BUNDLER) {
1065 		skb_queue_head_init(&tmpq);
1066 		l->stats.recv_bundles++;
1067 		l->stats.recv_bundled += msg_msgcnt(hdr);
1068 		while (tipc_msg_extract(skb, &iskb, &pos))
1069 			tipc_data_input(l, iskb, &tmpq);
1070 		tipc_skb_queue_splice_tail(&tmpq, inputq);
1071 		return 0;
1072 	} else if (usr == MSG_FRAGMENTER) {
1073 		l->stats.recv_fragments++;
1074 		if (tipc_buf_append(reasm_skb, &skb)) {
1075 			l->stats.recv_fragmented++;
1076 			tipc_data_input(l, skb, inputq);
1077 		} else if (!*reasm_skb && !link_is_bc_rcvlink(l)) {
1078 			pr_warn_ratelimited("Unable to build fragment list\n");
1079 			return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1080 		}
1081 		return 0;
1082 	} else if (usr == BCAST_PROTOCOL) {
1083 		tipc_bcast_lock(l->net);
1084 		tipc_link_bc_init_rcv(l->bc_rcvlink, hdr);
1085 		tipc_bcast_unlock(l->net);
1086 	}
1087 drop:
1088 	kfree_skb(skb);
1089 	return 0;
1090 }
1091 
1092 static bool tipc_link_release_pkts(struct tipc_link *l, u16 acked)
1093 {
1094 	bool released = false;
1095 	struct sk_buff *skb, *tmp;
1096 
1097 	skb_queue_walk_safe(&l->transmq, skb, tmp) {
1098 		if (more(buf_seqno(skb), acked))
1099 			break;
1100 		__skb_unlink(skb, &l->transmq);
1101 		kfree_skb(skb);
1102 		released = true;
1103 	}
1104 	return released;
1105 }
1106 
1107 /* tipc_link_build_state_msg: prepare link state message for transmission
1108  *
1109  * Note that sending of broadcast ack is coordinated among nodes, to reduce
1110  * risk of ack storms towards the sender
1111  */
1112 int tipc_link_build_state_msg(struct tipc_link *l, struct sk_buff_head *xmitq)
1113 {
1114 	if (!l)
1115 		return 0;
1116 
1117 	/* Broadcast ACK must be sent via a unicast link => defer to caller */
1118 	if (link_is_bc_rcvlink(l)) {
1119 		if (((l->rcv_nxt ^ tipc_own_addr(l->net)) & 0xf) != 0xf)
1120 			return 0;
1121 		l->rcv_unacked = 0;
1122 		return TIPC_LINK_SND_BC_ACK;
1123 	}
1124 
1125 	/* Unicast ACK */
1126 	l->rcv_unacked = 0;
1127 	l->stats.sent_acks++;
1128 	tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, 0, xmitq);
1129 	return 0;
1130 }
1131 
1132 /* tipc_link_build_reset_msg: prepare link RESET or ACTIVATE message
1133  */
1134 void tipc_link_build_reset_msg(struct tipc_link *l, struct sk_buff_head *xmitq)
1135 {
1136 	int mtyp = RESET_MSG;
1137 	struct sk_buff *skb;
1138 
1139 	if (l->state == LINK_ESTABLISHING)
1140 		mtyp = ACTIVATE_MSG;
1141 
1142 	tipc_link_build_proto_msg(l, mtyp, 0, 0, 0, 0, xmitq);
1143 
1144 	/* Inform peer that this endpoint is going down if applicable */
1145 	skb = skb_peek_tail(xmitq);
1146 	if (skb && (l->state == LINK_RESET))
1147 		msg_set_peer_stopping(buf_msg(skb), 1);
1148 }
1149 
1150 /* tipc_link_build_nack_msg: prepare link nack message for transmission
1151  */
1152 static void tipc_link_build_nack_msg(struct tipc_link *l,
1153 				     struct sk_buff_head *xmitq)
1154 {
1155 	u32 def_cnt = ++l->stats.deferred_recv;
1156 
1157 	if (link_is_bc_rcvlink(l))
1158 		return;
1159 
1160 	if ((skb_queue_len(&l->deferdq) == 1) || !(def_cnt % TIPC_NACK_INTV))
1161 		tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, 0, xmitq);
1162 }
1163 
1164 /* tipc_link_rcv - process TIPC packets/messages arriving from off-node
1165  * @l: the link that should handle the message
1166  * @skb: TIPC packet
1167  * @xmitq: queue to place packets to be sent after this call
1168  */
1169 int tipc_link_rcv(struct tipc_link *l, struct sk_buff *skb,
1170 		  struct sk_buff_head *xmitq)
1171 {
1172 	struct sk_buff_head *defq = &l->deferdq;
1173 	struct tipc_msg *hdr;
1174 	u16 seqno, rcv_nxt, win_lim;
1175 	int rc = 0;
1176 
1177 	do {
1178 		hdr = buf_msg(skb);
1179 		seqno = msg_seqno(hdr);
1180 		rcv_nxt = l->rcv_nxt;
1181 		win_lim = rcv_nxt + TIPC_MAX_LINK_WIN;
1182 
1183 		/* Verify and update link state */
1184 		if (unlikely(msg_user(hdr) == LINK_PROTOCOL))
1185 			return tipc_link_proto_rcv(l, skb, xmitq);
1186 
1187 		if (unlikely(!link_is_up(l))) {
1188 			if (l->state == LINK_ESTABLISHING)
1189 				rc = TIPC_LINK_UP_EVT;
1190 			goto drop;
1191 		}
1192 
1193 		/* Don't send probe at next timeout expiration */
1194 		l->silent_intv_cnt = 0;
1195 
1196 		/* Drop if outside receive window */
1197 		if (unlikely(less(seqno, rcv_nxt) || more(seqno, win_lim))) {
1198 			l->stats.duplicates++;
1199 			goto drop;
1200 		}
1201 
1202 		/* Forward queues and wake up waiting users */
1203 		if (likely(tipc_link_release_pkts(l, msg_ack(hdr)))) {
1204 			tipc_link_advance_backlog(l, xmitq);
1205 			if (unlikely(!skb_queue_empty(&l->wakeupq)))
1206 				link_prepare_wakeup(l);
1207 		}
1208 
1209 		/* Defer delivery if sequence gap */
1210 		if (unlikely(seqno != rcv_nxt)) {
1211 			__tipc_skb_queue_sorted(defq, seqno, skb);
1212 			tipc_link_build_nack_msg(l, xmitq);
1213 			break;
1214 		}
1215 
1216 		/* Deliver packet */
1217 		l->rcv_nxt++;
1218 		l->stats.recv_info++;
1219 		if (!tipc_data_input(l, skb, l->inputq))
1220 			rc |= tipc_link_input(l, skb, l->inputq);
1221 		if (unlikely(++l->rcv_unacked >= TIPC_MIN_LINK_WIN))
1222 			rc |= tipc_link_build_state_msg(l, xmitq);
1223 		if (unlikely(rc & ~TIPC_LINK_SND_BC_ACK))
1224 			break;
1225 	} while ((skb = __skb_dequeue(defq)));
1226 
1227 	return rc;
1228 drop:
1229 	kfree_skb(skb);
1230 	return rc;
1231 }
1232 
1233 static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
1234 				      u16 rcvgap, int tolerance, int priority,
1235 				      struct sk_buff_head *xmitq)
1236 {
1237 	struct sk_buff *skb;
1238 	struct tipc_msg *hdr;
1239 	struct sk_buff_head *dfq = &l->deferdq;
1240 	bool node_up = link_is_up(l->bc_rcvlink);
1241 
1242 	/* Don't send protocol message during reset or link failover */
1243 	if (tipc_link_is_blocked(l))
1244 		return;
1245 
1246 	if (!tipc_link_is_up(l) && (mtyp == STATE_MSG))
1247 		return;
1248 
1249 	if (!skb_queue_empty(dfq))
1250 		rcvgap = buf_seqno(skb_peek(dfq)) - l->rcv_nxt;
1251 
1252 	skb = tipc_msg_create(LINK_PROTOCOL, mtyp, INT_H_SIZE,
1253 			      TIPC_MAX_IF_NAME, l->addr,
1254 			      tipc_own_addr(l->net), 0, 0, 0);
1255 	if (!skb)
1256 		return;
1257 
1258 	hdr = buf_msg(skb);
1259 	msg_set_session(hdr, l->session);
1260 	msg_set_bearer_id(hdr, l->bearer_id);
1261 	msg_set_net_plane(hdr, l->net_plane);
1262 	msg_set_next_sent(hdr, l->snd_nxt);
1263 	msg_set_ack(hdr, l->rcv_nxt - 1);
1264 	msg_set_bcast_ack(hdr, l->bc_rcvlink->rcv_nxt - 1);
1265 	msg_set_last_bcast(hdr, l->bc_sndlink->snd_nxt - 1);
1266 	msg_set_link_tolerance(hdr, tolerance);
1267 	msg_set_linkprio(hdr, priority);
1268 	msg_set_redundant_link(hdr, node_up);
1269 	msg_set_seq_gap(hdr, 0);
1270 	msg_set_seqno(hdr, l->snd_nxt + U16_MAX / 2);
1271 
1272 	if (mtyp == STATE_MSG) {
1273 		msg_set_seq_gap(hdr, rcvgap);
1274 		msg_set_size(hdr, INT_H_SIZE);
1275 		msg_set_probe(hdr, probe);
1276 		l->stats.sent_states++;
1277 		l->rcv_unacked = 0;
1278 	} else {
1279 		/* RESET_MSG or ACTIVATE_MSG */
1280 		msg_set_max_pkt(hdr, l->advertised_mtu);
1281 		strcpy(msg_data(hdr), l->if_name);
1282 	}
1283 	if (probe)
1284 		l->stats.sent_probes++;
1285 	if (rcvgap)
1286 		l->stats.sent_nacks++;
1287 	skb->priority = TC_PRIO_CONTROL;
1288 	__skb_queue_tail(xmitq, skb);
1289 }
1290 
1291 /* tipc_link_tnl_prepare(): prepare and return a list of tunnel packets
1292  * with contents of the link's transmit and backlog queues.
1293  */
1294 void tipc_link_tnl_prepare(struct tipc_link *l, struct tipc_link *tnl,
1295 			   int mtyp, struct sk_buff_head *xmitq)
1296 {
1297 	struct sk_buff *skb, *tnlskb;
1298 	struct tipc_msg *hdr, tnlhdr;
1299 	struct sk_buff_head *queue = &l->transmq;
1300 	struct sk_buff_head tmpxq, tnlq;
1301 	u16 pktlen, pktcnt, seqno = l->snd_nxt;
1302 
1303 	if (!tnl)
1304 		return;
1305 
1306 	skb_queue_head_init(&tnlq);
1307 	skb_queue_head_init(&tmpxq);
1308 
1309 	/* At least one packet required for safe algorithm => add dummy */
1310 	skb = tipc_msg_create(TIPC_LOW_IMPORTANCE, TIPC_DIRECT_MSG,
1311 			      BASIC_H_SIZE, 0, l->addr, tipc_own_addr(l->net),
1312 			      0, 0, TIPC_ERR_NO_PORT);
1313 	if (!skb) {
1314 		pr_warn("%sunable to create tunnel packet\n", link_co_err);
1315 		return;
1316 	}
1317 	skb_queue_tail(&tnlq, skb);
1318 	tipc_link_xmit(l, &tnlq, &tmpxq);
1319 	__skb_queue_purge(&tmpxq);
1320 
1321 	/* Initialize reusable tunnel packet header */
1322 	tipc_msg_init(tipc_own_addr(l->net), &tnlhdr, TUNNEL_PROTOCOL,
1323 		      mtyp, INT_H_SIZE, l->addr);
1324 	pktcnt = skb_queue_len(&l->transmq) + skb_queue_len(&l->backlogq);
1325 	msg_set_msgcnt(&tnlhdr, pktcnt);
1326 	msg_set_bearer_id(&tnlhdr, l->peer_bearer_id);
1327 tnl:
1328 	/* Wrap each packet into a tunnel packet */
1329 	skb_queue_walk(queue, skb) {
1330 		hdr = buf_msg(skb);
1331 		if (queue == &l->backlogq)
1332 			msg_set_seqno(hdr, seqno++);
1333 		pktlen = msg_size(hdr);
1334 		msg_set_size(&tnlhdr, pktlen + INT_H_SIZE);
1335 		tnlskb = tipc_buf_acquire(pktlen + INT_H_SIZE);
1336 		if (!tnlskb) {
1337 			pr_warn("%sunable to send packet\n", link_co_err);
1338 			return;
1339 		}
1340 		skb_copy_to_linear_data(tnlskb, &tnlhdr, INT_H_SIZE);
1341 		skb_copy_to_linear_data_offset(tnlskb, INT_H_SIZE, hdr, pktlen);
1342 		__skb_queue_tail(&tnlq, tnlskb);
1343 	}
1344 	if (queue != &l->backlogq) {
1345 		queue = &l->backlogq;
1346 		goto tnl;
1347 	}
1348 
1349 	tipc_link_xmit(tnl, &tnlq, xmitq);
1350 
1351 	if (mtyp == FAILOVER_MSG) {
1352 		tnl->drop_point = l->rcv_nxt;
1353 		tnl->failover_reasm_skb = l->reasm_buf;
1354 		l->reasm_buf = NULL;
1355 	}
1356 }
1357 
1358 /* tipc_link_proto_rcv(): receive link level protocol message :
1359  * Note that network plane id propagates through the network, and may
1360  * change at any time. The node with lowest numerical id determines
1361  * network plane
1362  */
1363 static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
1364 			       struct sk_buff_head *xmitq)
1365 {
1366 	struct tipc_msg *hdr = buf_msg(skb);
1367 	u16 rcvgap = 0;
1368 	u16 ack = msg_ack(hdr);
1369 	u16 gap = msg_seq_gap(hdr);
1370 	u16 peers_snd_nxt =  msg_next_sent(hdr);
1371 	u16 peers_tol = msg_link_tolerance(hdr);
1372 	u16 peers_prio = msg_linkprio(hdr);
1373 	u16 rcv_nxt = l->rcv_nxt;
1374 	int mtyp = msg_type(hdr);
1375 	char *if_name;
1376 	int rc = 0;
1377 
1378 	if (tipc_link_is_blocked(l) || !xmitq)
1379 		goto exit;
1380 
1381 	if (tipc_own_addr(l->net) > msg_prevnode(hdr))
1382 		l->net_plane = msg_net_plane(hdr);
1383 
1384 	switch (mtyp) {
1385 	case RESET_MSG:
1386 
1387 		/* Ignore duplicate RESET with old session number */
1388 		if ((less_eq(msg_session(hdr), l->peer_session)) &&
1389 		    (l->peer_session != ANY_SESSION))
1390 			break;
1391 		/* fall thru' */
1392 
1393 	case ACTIVATE_MSG:
1394 		skb_linearize(skb);
1395 		hdr = buf_msg(skb);
1396 
1397 		/* Complete own link name with peer's interface name */
1398 		if_name =  strrchr(l->name, ':') + 1;
1399 		if (sizeof(l->name) - (if_name - l->name) <= TIPC_MAX_IF_NAME)
1400 			break;
1401 		if (msg_data_sz(hdr) < TIPC_MAX_IF_NAME)
1402 			break;
1403 		strncpy(if_name, msg_data(hdr),	TIPC_MAX_IF_NAME);
1404 
1405 		/* Update own tolerance if peer indicates a non-zero value */
1406 		if (in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL))
1407 			l->tolerance = peers_tol;
1408 
1409 		/* Update own priority if peer's priority is higher */
1410 		if (in_range(peers_prio, l->priority + 1, TIPC_MAX_LINK_PRI))
1411 			l->priority = peers_prio;
1412 
1413 		/* ACTIVATE_MSG serves as PEER_RESET if link is already down */
1414 		if (msg_peer_stopping(hdr))
1415 			rc = tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1416 		else if ((mtyp == RESET_MSG) || !link_is_up(l))
1417 			rc = tipc_link_fsm_evt(l, LINK_PEER_RESET_EVT);
1418 
1419 		/* ACTIVATE_MSG takes up link if it was already locally reset */
1420 		if ((mtyp == ACTIVATE_MSG) && (l->state == LINK_ESTABLISHING))
1421 			rc = TIPC_LINK_UP_EVT;
1422 
1423 		l->peer_session = msg_session(hdr);
1424 		l->peer_bearer_id = msg_bearer_id(hdr);
1425 		if (l->mtu > msg_max_pkt(hdr))
1426 			l->mtu = msg_max_pkt(hdr);
1427 		break;
1428 
1429 	case STATE_MSG:
1430 
1431 		/* Update own tolerance if peer indicates a non-zero value */
1432 		if (in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL))
1433 			l->tolerance = peers_tol;
1434 
1435 		if (peers_prio && in_range(peers_prio, TIPC_MIN_LINK_PRI,
1436 					   TIPC_MAX_LINK_PRI)) {
1437 			l->priority = peers_prio;
1438 			rc = tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1439 		}
1440 
1441 		l->silent_intv_cnt = 0;
1442 		l->stats.recv_states++;
1443 		if (msg_probe(hdr))
1444 			l->stats.recv_probes++;
1445 
1446 		if (!link_is_up(l)) {
1447 			if (l->state == LINK_ESTABLISHING)
1448 				rc = TIPC_LINK_UP_EVT;
1449 			break;
1450 		}
1451 
1452 		/* Send NACK if peer has sent pkts we haven't received yet */
1453 		if (more(peers_snd_nxt, rcv_nxt) && !tipc_link_is_synching(l))
1454 			rcvgap = peers_snd_nxt - l->rcv_nxt;
1455 		if (rcvgap || (msg_probe(hdr)))
1456 			tipc_link_build_proto_msg(l, STATE_MSG, 0, rcvgap,
1457 						  0, 0, xmitq);
1458 		tipc_link_release_pkts(l, ack);
1459 
1460 		/* If NACK, retransmit will now start at right position */
1461 		if (gap) {
1462 			rc = tipc_link_retrans(l, ack + 1, ack + gap, xmitq);
1463 			l->stats.recv_nacks++;
1464 		}
1465 
1466 		tipc_link_advance_backlog(l, xmitq);
1467 		if (unlikely(!skb_queue_empty(&l->wakeupq)))
1468 			link_prepare_wakeup(l);
1469 	}
1470 exit:
1471 	kfree_skb(skb);
1472 	return rc;
1473 }
1474 
1475 /* tipc_link_build_bc_proto_msg() - create broadcast protocol message
1476  */
1477 static bool tipc_link_build_bc_proto_msg(struct tipc_link *l, bool bcast,
1478 					 u16 peers_snd_nxt,
1479 					 struct sk_buff_head *xmitq)
1480 {
1481 	struct sk_buff *skb;
1482 	struct tipc_msg *hdr;
1483 	struct sk_buff *dfrd_skb = skb_peek(&l->deferdq);
1484 	u16 ack = l->rcv_nxt - 1;
1485 	u16 gap_to = peers_snd_nxt - 1;
1486 
1487 	skb = tipc_msg_create(BCAST_PROTOCOL, STATE_MSG, INT_H_SIZE,
1488 			      0, l->addr, tipc_own_addr(l->net), 0, 0, 0);
1489 	if (!skb)
1490 		return false;
1491 	hdr = buf_msg(skb);
1492 	msg_set_last_bcast(hdr, l->bc_sndlink->snd_nxt - 1);
1493 	msg_set_bcast_ack(hdr, ack);
1494 	msg_set_bcgap_after(hdr, ack);
1495 	if (dfrd_skb)
1496 		gap_to = buf_seqno(dfrd_skb) - 1;
1497 	msg_set_bcgap_to(hdr, gap_to);
1498 	msg_set_non_seq(hdr, bcast);
1499 	__skb_queue_tail(xmitq, skb);
1500 	return true;
1501 }
1502 
1503 /* tipc_link_build_bc_init_msg() - synchronize broadcast link endpoints.
1504  *
1505  * Give a newly added peer node the sequence number where it should
1506  * start receiving and acking broadcast packets.
1507  */
1508 static void tipc_link_build_bc_init_msg(struct tipc_link *l,
1509 					struct sk_buff_head *xmitq)
1510 {
1511 	struct sk_buff_head list;
1512 
1513 	__skb_queue_head_init(&list);
1514 	if (!tipc_link_build_bc_proto_msg(l->bc_rcvlink, false, 0, &list))
1515 		return;
1516 	tipc_link_xmit(l, &list, xmitq);
1517 }
1518 
1519 /* tipc_link_bc_init_rcv - receive initial broadcast synch data from peer
1520  */
1521 void tipc_link_bc_init_rcv(struct tipc_link *l, struct tipc_msg *hdr)
1522 {
1523 	int mtyp = msg_type(hdr);
1524 	u16 peers_snd_nxt = msg_bc_snd_nxt(hdr);
1525 
1526 	if (link_is_up(l))
1527 		return;
1528 
1529 	if (msg_user(hdr) == BCAST_PROTOCOL) {
1530 		l->rcv_nxt = peers_snd_nxt;
1531 		l->state = LINK_ESTABLISHED;
1532 		return;
1533 	}
1534 
1535 	if (l->peer_caps & TIPC_BCAST_SYNCH)
1536 		return;
1537 
1538 	if (msg_peer_node_is_up(hdr))
1539 		return;
1540 
1541 	/* Compatibility: accept older, less safe initial synch data */
1542 	if ((mtyp == RESET_MSG) || (mtyp == ACTIVATE_MSG))
1543 		l->rcv_nxt = peers_snd_nxt;
1544 }
1545 
1546 /* tipc_link_bc_sync_rcv - update rcv link according to peer's send state
1547  */
1548 void tipc_link_bc_sync_rcv(struct tipc_link *l, struct tipc_msg *hdr,
1549 			   struct sk_buff_head *xmitq)
1550 {
1551 	u16 peers_snd_nxt = msg_bc_snd_nxt(hdr);
1552 
1553 	if (!link_is_up(l))
1554 		return;
1555 
1556 	if (!msg_peer_node_is_up(hdr))
1557 		return;
1558 
1559 	l->bc_peer_is_up = true;
1560 
1561 	/* Ignore if peers_snd_nxt goes beyond receive window */
1562 	if (more(peers_snd_nxt, l->rcv_nxt + l->window))
1563 		return;
1564 
1565 	if (!more(peers_snd_nxt, l->rcv_nxt)) {
1566 		l->nack_state = BC_NACK_SND_CONDITIONAL;
1567 		return;
1568 	}
1569 
1570 	/* Don't NACK if one was recently sent or peeked */
1571 	if (l->nack_state == BC_NACK_SND_SUPPRESS) {
1572 		l->nack_state = BC_NACK_SND_UNCONDITIONAL;
1573 		return;
1574 	}
1575 
1576 	/* Conditionally delay NACK sending until next synch rcv */
1577 	if (l->nack_state == BC_NACK_SND_CONDITIONAL) {
1578 		l->nack_state = BC_NACK_SND_UNCONDITIONAL;
1579 		if ((peers_snd_nxt - l->rcv_nxt) < TIPC_MIN_LINK_WIN)
1580 			return;
1581 	}
1582 
1583 	/* Send NACK now but suppress next one */
1584 	tipc_link_build_bc_proto_msg(l, true, peers_snd_nxt, xmitq);
1585 	l->nack_state = BC_NACK_SND_SUPPRESS;
1586 }
1587 
1588 void tipc_link_bc_ack_rcv(struct tipc_link *l, u16 acked,
1589 			  struct sk_buff_head *xmitq)
1590 {
1591 	struct sk_buff *skb, *tmp;
1592 	struct tipc_link *snd_l = l->bc_sndlink;
1593 
1594 	if (!link_is_up(l) || !l->bc_peer_is_up)
1595 		return;
1596 
1597 	if (!more(acked, l->acked))
1598 		return;
1599 
1600 	/* Skip over packets peer has already acked */
1601 	skb_queue_walk(&snd_l->transmq, skb) {
1602 		if (more(buf_seqno(skb), l->acked))
1603 			break;
1604 	}
1605 
1606 	/* Update/release the packets peer is acking now */
1607 	skb_queue_walk_from_safe(&snd_l->transmq, skb, tmp) {
1608 		if (more(buf_seqno(skb), acked))
1609 			break;
1610 		if (!--TIPC_SKB_CB(skb)->ackers) {
1611 			__skb_unlink(skb, &snd_l->transmq);
1612 			kfree_skb(skb);
1613 		}
1614 	}
1615 	l->acked = acked;
1616 	tipc_link_advance_backlog(snd_l, xmitq);
1617 	if (unlikely(!skb_queue_empty(&snd_l->wakeupq)))
1618 		link_prepare_wakeup(snd_l);
1619 }
1620 
1621 /* tipc_link_bc_nack_rcv(): receive broadcast nack message
1622  */
1623 int tipc_link_bc_nack_rcv(struct tipc_link *l, struct sk_buff *skb,
1624 			  struct sk_buff_head *xmitq)
1625 {
1626 	struct tipc_msg *hdr = buf_msg(skb);
1627 	u32 dnode = msg_destnode(hdr);
1628 	int mtyp = msg_type(hdr);
1629 	u16 acked = msg_bcast_ack(hdr);
1630 	u16 from = acked + 1;
1631 	u16 to = msg_bcgap_to(hdr);
1632 	u16 peers_snd_nxt = to + 1;
1633 	int rc = 0;
1634 
1635 	kfree_skb(skb);
1636 
1637 	if (!tipc_link_is_up(l) || !l->bc_peer_is_up)
1638 		return 0;
1639 
1640 	if (mtyp != STATE_MSG)
1641 		return 0;
1642 
1643 	if (dnode == tipc_own_addr(l->net)) {
1644 		tipc_link_bc_ack_rcv(l, acked, xmitq);
1645 		rc = tipc_link_retrans(l->bc_sndlink, from, to, xmitq);
1646 		l->stats.recv_nacks++;
1647 		return rc;
1648 	}
1649 
1650 	/* Msg for other node => suppress own NACK at next sync if applicable */
1651 	if (more(peers_snd_nxt, l->rcv_nxt) && !less(l->rcv_nxt, from))
1652 		l->nack_state = BC_NACK_SND_SUPPRESS;
1653 
1654 	return 0;
1655 }
1656 
1657 void tipc_link_set_queue_limits(struct tipc_link *l, u32 win)
1658 {
1659 	int max_bulk = TIPC_MAX_PUBLICATIONS / (l->mtu / ITEM_SIZE);
1660 
1661 	l->window = win;
1662 	l->backlog[TIPC_LOW_IMPORTANCE].limit      = win / 2;
1663 	l->backlog[TIPC_MEDIUM_IMPORTANCE].limit   = win;
1664 	l->backlog[TIPC_HIGH_IMPORTANCE].limit     = win / 2 * 3;
1665 	l->backlog[TIPC_CRITICAL_IMPORTANCE].limit = win * 2;
1666 	l->backlog[TIPC_SYSTEM_IMPORTANCE].limit   = max_bulk;
1667 }
1668 
1669 /**
1670  * link_reset_stats - reset link statistics
1671  * @l: pointer to link
1672  */
1673 void tipc_link_reset_stats(struct tipc_link *l)
1674 {
1675 	memset(&l->stats, 0, sizeof(l->stats));
1676 	if (!link_is_bc_sndlink(l)) {
1677 		l->stats.sent_info = l->snd_nxt;
1678 		l->stats.recv_info = l->rcv_nxt;
1679 	}
1680 }
1681 
1682 static void link_print(struct tipc_link *l, const char *str)
1683 {
1684 	struct sk_buff *hskb = skb_peek(&l->transmq);
1685 	u16 head = hskb ? msg_seqno(buf_msg(hskb)) : l->snd_nxt - 1;
1686 	u16 tail = l->snd_nxt - 1;
1687 
1688 	pr_info("%s Link <%s> state %x\n", str, l->name, l->state);
1689 	pr_info("XMTQ: %u [%u-%u], BKLGQ: %u, SNDNX: %u, RCVNX: %u\n",
1690 		skb_queue_len(&l->transmq), head, tail,
1691 		skb_queue_len(&l->backlogq), l->snd_nxt, l->rcv_nxt);
1692 }
1693 
1694 /* Parse and validate nested (link) properties valid for media, bearer and link
1695  */
1696 int tipc_nl_parse_link_prop(struct nlattr *prop, struct nlattr *props[])
1697 {
1698 	int err;
1699 
1700 	err = nla_parse_nested(props, TIPC_NLA_PROP_MAX, prop,
1701 			       tipc_nl_prop_policy);
1702 	if (err)
1703 		return err;
1704 
1705 	if (props[TIPC_NLA_PROP_PRIO]) {
1706 		u32 prio;
1707 
1708 		prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
1709 		if (prio > TIPC_MAX_LINK_PRI)
1710 			return -EINVAL;
1711 	}
1712 
1713 	if (props[TIPC_NLA_PROP_TOL]) {
1714 		u32 tol;
1715 
1716 		tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
1717 		if ((tol < TIPC_MIN_LINK_TOL) || (tol > TIPC_MAX_LINK_TOL))
1718 			return -EINVAL;
1719 	}
1720 
1721 	if (props[TIPC_NLA_PROP_WIN]) {
1722 		u32 win;
1723 
1724 		win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
1725 		if ((win < TIPC_MIN_LINK_WIN) || (win > TIPC_MAX_LINK_WIN))
1726 			return -EINVAL;
1727 	}
1728 
1729 	return 0;
1730 }
1731 
1732 static int __tipc_nl_add_stats(struct sk_buff *skb, struct tipc_stats *s)
1733 {
1734 	int i;
1735 	struct nlattr *stats;
1736 
1737 	struct nla_map {
1738 		u32 key;
1739 		u32 val;
1740 	};
1741 
1742 	struct nla_map map[] = {
1743 		{TIPC_NLA_STATS_RX_INFO, s->recv_info},
1744 		{TIPC_NLA_STATS_RX_FRAGMENTS, s->recv_fragments},
1745 		{TIPC_NLA_STATS_RX_FRAGMENTED, s->recv_fragmented},
1746 		{TIPC_NLA_STATS_RX_BUNDLES, s->recv_bundles},
1747 		{TIPC_NLA_STATS_RX_BUNDLED, s->recv_bundled},
1748 		{TIPC_NLA_STATS_TX_INFO, s->sent_info},
1749 		{TIPC_NLA_STATS_TX_FRAGMENTS, s->sent_fragments},
1750 		{TIPC_NLA_STATS_TX_FRAGMENTED, s->sent_fragmented},
1751 		{TIPC_NLA_STATS_TX_BUNDLES, s->sent_bundles},
1752 		{TIPC_NLA_STATS_TX_BUNDLED, s->sent_bundled},
1753 		{TIPC_NLA_STATS_MSG_PROF_TOT, (s->msg_length_counts) ?
1754 			s->msg_length_counts : 1},
1755 		{TIPC_NLA_STATS_MSG_LEN_CNT, s->msg_length_counts},
1756 		{TIPC_NLA_STATS_MSG_LEN_TOT, s->msg_lengths_total},
1757 		{TIPC_NLA_STATS_MSG_LEN_P0, s->msg_length_profile[0]},
1758 		{TIPC_NLA_STATS_MSG_LEN_P1, s->msg_length_profile[1]},
1759 		{TIPC_NLA_STATS_MSG_LEN_P2, s->msg_length_profile[2]},
1760 		{TIPC_NLA_STATS_MSG_LEN_P3, s->msg_length_profile[3]},
1761 		{TIPC_NLA_STATS_MSG_LEN_P4, s->msg_length_profile[4]},
1762 		{TIPC_NLA_STATS_MSG_LEN_P5, s->msg_length_profile[5]},
1763 		{TIPC_NLA_STATS_MSG_LEN_P6, s->msg_length_profile[6]},
1764 		{TIPC_NLA_STATS_RX_STATES, s->recv_states},
1765 		{TIPC_NLA_STATS_RX_PROBES, s->recv_probes},
1766 		{TIPC_NLA_STATS_RX_NACKS, s->recv_nacks},
1767 		{TIPC_NLA_STATS_RX_DEFERRED, s->deferred_recv},
1768 		{TIPC_NLA_STATS_TX_STATES, s->sent_states},
1769 		{TIPC_NLA_STATS_TX_PROBES, s->sent_probes},
1770 		{TIPC_NLA_STATS_TX_NACKS, s->sent_nacks},
1771 		{TIPC_NLA_STATS_TX_ACKS, s->sent_acks},
1772 		{TIPC_NLA_STATS_RETRANSMITTED, s->retransmitted},
1773 		{TIPC_NLA_STATS_DUPLICATES, s->duplicates},
1774 		{TIPC_NLA_STATS_LINK_CONGS, s->link_congs},
1775 		{TIPC_NLA_STATS_MAX_QUEUE, s->max_queue_sz},
1776 		{TIPC_NLA_STATS_AVG_QUEUE, s->queue_sz_counts ?
1777 			(s->accu_queue_sz / s->queue_sz_counts) : 0}
1778 	};
1779 
1780 	stats = nla_nest_start(skb, TIPC_NLA_LINK_STATS);
1781 	if (!stats)
1782 		return -EMSGSIZE;
1783 
1784 	for (i = 0; i <  ARRAY_SIZE(map); i++)
1785 		if (nla_put_u32(skb, map[i].key, map[i].val))
1786 			goto msg_full;
1787 
1788 	nla_nest_end(skb, stats);
1789 
1790 	return 0;
1791 msg_full:
1792 	nla_nest_cancel(skb, stats);
1793 
1794 	return -EMSGSIZE;
1795 }
1796 
1797 /* Caller should hold appropriate locks to protect the link */
1798 int __tipc_nl_add_link(struct net *net, struct tipc_nl_msg *msg,
1799 		       struct tipc_link *link, int nlflags)
1800 {
1801 	int err;
1802 	void *hdr;
1803 	struct nlattr *attrs;
1804 	struct nlattr *prop;
1805 	struct tipc_net *tn = net_generic(net, tipc_net_id);
1806 
1807 	hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
1808 			  nlflags, TIPC_NL_LINK_GET);
1809 	if (!hdr)
1810 		return -EMSGSIZE;
1811 
1812 	attrs = nla_nest_start(msg->skb, TIPC_NLA_LINK);
1813 	if (!attrs)
1814 		goto msg_full;
1815 
1816 	if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, link->name))
1817 		goto attr_msg_full;
1818 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_DEST,
1819 			tipc_cluster_mask(tn->own_addr)))
1820 		goto attr_msg_full;
1821 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_MTU, link->mtu))
1822 		goto attr_msg_full;
1823 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, link->rcv_nxt))
1824 		goto attr_msg_full;
1825 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, link->snd_nxt))
1826 		goto attr_msg_full;
1827 
1828 	if (tipc_link_is_up(link))
1829 		if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
1830 			goto attr_msg_full;
1831 	if (link->active)
1832 		if (nla_put_flag(msg->skb, TIPC_NLA_LINK_ACTIVE))
1833 			goto attr_msg_full;
1834 
1835 	prop = nla_nest_start(msg->skb, TIPC_NLA_LINK_PROP);
1836 	if (!prop)
1837 		goto attr_msg_full;
1838 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
1839 		goto prop_msg_full;
1840 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_TOL, link->tolerance))
1841 		goto prop_msg_full;
1842 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN,
1843 			link->window))
1844 		goto prop_msg_full;
1845 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
1846 		goto prop_msg_full;
1847 	nla_nest_end(msg->skb, prop);
1848 
1849 	err = __tipc_nl_add_stats(msg->skb, &link->stats);
1850 	if (err)
1851 		goto attr_msg_full;
1852 
1853 	nla_nest_end(msg->skb, attrs);
1854 	genlmsg_end(msg->skb, hdr);
1855 
1856 	return 0;
1857 
1858 prop_msg_full:
1859 	nla_nest_cancel(msg->skb, prop);
1860 attr_msg_full:
1861 	nla_nest_cancel(msg->skb, attrs);
1862 msg_full:
1863 	genlmsg_cancel(msg->skb, hdr);
1864 
1865 	return -EMSGSIZE;
1866 }
1867 
1868 static int __tipc_nl_add_bc_link_stat(struct sk_buff *skb,
1869 				      struct tipc_stats *stats)
1870 {
1871 	int i;
1872 	struct nlattr *nest;
1873 
1874 	struct nla_map {
1875 		__u32 key;
1876 		__u32 val;
1877 	};
1878 
1879 	struct nla_map map[] = {
1880 		{TIPC_NLA_STATS_RX_INFO, stats->recv_info},
1881 		{TIPC_NLA_STATS_RX_FRAGMENTS, stats->recv_fragments},
1882 		{TIPC_NLA_STATS_RX_FRAGMENTED, stats->recv_fragmented},
1883 		{TIPC_NLA_STATS_RX_BUNDLES, stats->recv_bundles},
1884 		{TIPC_NLA_STATS_RX_BUNDLED, stats->recv_bundled},
1885 		{TIPC_NLA_STATS_TX_INFO, stats->sent_info},
1886 		{TIPC_NLA_STATS_TX_FRAGMENTS, stats->sent_fragments},
1887 		{TIPC_NLA_STATS_TX_FRAGMENTED, stats->sent_fragmented},
1888 		{TIPC_NLA_STATS_TX_BUNDLES, stats->sent_bundles},
1889 		{TIPC_NLA_STATS_TX_BUNDLED, stats->sent_bundled},
1890 		{TIPC_NLA_STATS_RX_NACKS, stats->recv_nacks},
1891 		{TIPC_NLA_STATS_RX_DEFERRED, stats->deferred_recv},
1892 		{TIPC_NLA_STATS_TX_NACKS, stats->sent_nacks},
1893 		{TIPC_NLA_STATS_TX_ACKS, stats->sent_acks},
1894 		{TIPC_NLA_STATS_RETRANSMITTED, stats->retransmitted},
1895 		{TIPC_NLA_STATS_DUPLICATES, stats->duplicates},
1896 		{TIPC_NLA_STATS_LINK_CONGS, stats->link_congs},
1897 		{TIPC_NLA_STATS_MAX_QUEUE, stats->max_queue_sz},
1898 		{TIPC_NLA_STATS_AVG_QUEUE, stats->queue_sz_counts ?
1899 			(stats->accu_queue_sz / stats->queue_sz_counts) : 0}
1900 	};
1901 
1902 	nest = nla_nest_start(skb, TIPC_NLA_LINK_STATS);
1903 	if (!nest)
1904 		return -EMSGSIZE;
1905 
1906 	for (i = 0; i <  ARRAY_SIZE(map); i++)
1907 		if (nla_put_u32(skb, map[i].key, map[i].val))
1908 			goto msg_full;
1909 
1910 	nla_nest_end(skb, nest);
1911 
1912 	return 0;
1913 msg_full:
1914 	nla_nest_cancel(skb, nest);
1915 
1916 	return -EMSGSIZE;
1917 }
1918 
1919 int tipc_nl_add_bc_link(struct net *net, struct tipc_nl_msg *msg)
1920 {
1921 	int err;
1922 	void *hdr;
1923 	struct nlattr *attrs;
1924 	struct nlattr *prop;
1925 	struct tipc_net *tn = net_generic(net, tipc_net_id);
1926 	struct tipc_link *bcl = tn->bcl;
1927 
1928 	if (!bcl)
1929 		return 0;
1930 
1931 	tipc_bcast_lock(net);
1932 
1933 	hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
1934 			  NLM_F_MULTI, TIPC_NL_LINK_GET);
1935 	if (!hdr) {
1936 		tipc_bcast_unlock(net);
1937 		return -EMSGSIZE;
1938 	}
1939 
1940 	attrs = nla_nest_start(msg->skb, TIPC_NLA_LINK);
1941 	if (!attrs)
1942 		goto msg_full;
1943 
1944 	/* The broadcast link is always up */
1945 	if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
1946 		goto attr_msg_full;
1947 
1948 	if (nla_put_flag(msg->skb, TIPC_NLA_LINK_BROADCAST))
1949 		goto attr_msg_full;
1950 	if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, bcl->name))
1951 		goto attr_msg_full;
1952 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, bcl->rcv_nxt))
1953 		goto attr_msg_full;
1954 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, bcl->snd_nxt))
1955 		goto attr_msg_full;
1956 
1957 	prop = nla_nest_start(msg->skb, TIPC_NLA_LINK_PROP);
1958 	if (!prop)
1959 		goto attr_msg_full;
1960 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN, bcl->window))
1961 		goto prop_msg_full;
1962 	nla_nest_end(msg->skb, prop);
1963 
1964 	err = __tipc_nl_add_bc_link_stat(msg->skb, &bcl->stats);
1965 	if (err)
1966 		goto attr_msg_full;
1967 
1968 	tipc_bcast_unlock(net);
1969 	nla_nest_end(msg->skb, attrs);
1970 	genlmsg_end(msg->skb, hdr);
1971 
1972 	return 0;
1973 
1974 prop_msg_full:
1975 	nla_nest_cancel(msg->skb, prop);
1976 attr_msg_full:
1977 	nla_nest_cancel(msg->skb, attrs);
1978 msg_full:
1979 	tipc_bcast_unlock(net);
1980 	genlmsg_cancel(msg->skb, hdr);
1981 
1982 	return -EMSGSIZE;
1983 }
1984 
1985 void tipc_link_set_tolerance(struct tipc_link *l, u32 tol,
1986 			     struct sk_buff_head *xmitq)
1987 {
1988 	l->tolerance = tol;
1989 	tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, tol, 0, xmitq);
1990 }
1991 
1992 void tipc_link_set_prio(struct tipc_link *l, u32 prio,
1993 			struct sk_buff_head *xmitq)
1994 {
1995 	l->priority = prio;
1996 	tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, prio, xmitq);
1997 }
1998 
1999 void tipc_link_set_abort_limit(struct tipc_link *l, u32 limit)
2000 {
2001 	l->abort_limit = limit;
2002 }
2003