xref: /openbmc/linux/net/tipc/link.c (revision 2596e07a)
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 tipc_media_addr *media_addr;
127 	struct net *net;
128 
129 	/* Management and link supervision data */
130 	u32 peer_session;
131 	u32 peer_bearer_id;
132 	u32 bearer_id;
133 	u32 tolerance;
134 	unsigned long keepalive_intv;
135 	u32 abort_limit;
136 	u32 state;
137 	u16 peer_caps;
138 	bool active;
139 	u32 silent_intv_cnt;
140 	struct {
141 		unchar hdr[INT_H_SIZE];
142 		unchar body[TIPC_MAX_IF_NAME];
143 	} proto_msg;
144 	struct tipc_msg *pmsg;
145 	u32 priority;
146 	char net_plane;
147 
148 	/* Failover/synch */
149 	u16 drop_point;
150 	struct sk_buff *failover_reasm_skb;
151 
152 	/* Max packet negotiation */
153 	u16 mtu;
154 	u16 advertised_mtu;
155 
156 	/* Sending */
157 	struct sk_buff_head transmq;
158 	struct sk_buff_head backlogq;
159 	struct {
160 		u16 len;
161 		u16 limit;
162 	} backlog[5];
163 	u16 snd_nxt;
164 	u16 last_retransm;
165 	u16 window;
166 	u32 stale_count;
167 
168 	/* Reception */
169 	u16 rcv_nxt;
170 	u32 rcv_unacked;
171 	struct sk_buff_head deferdq;
172 	struct sk_buff_head *inputq;
173 	struct sk_buff_head *namedq;
174 
175 	/* Congestion handling */
176 	struct sk_buff_head wakeupq;
177 
178 	/* Fragmentation/reassembly */
179 	struct sk_buff *reasm_buf;
180 
181 	/* Broadcast */
182 	u16 ackers;
183 	u16 acked;
184 	struct tipc_link *bc_rcvlink;
185 	struct tipc_link *bc_sndlink;
186 	int nack_state;
187 	bool bc_peer_is_up;
188 
189 	/* Statistics */
190 	struct tipc_stats stats;
191 };
192 
193 /*
194  * Error message prefixes
195  */
196 static const char *link_co_err = "Link tunneling error, ";
197 static const char *link_rst_msg = "Resetting link ";
198 
199 /* Properties valid for media, bearar and link */
200 static const struct nla_policy tipc_nl_prop_policy[TIPC_NLA_PROP_MAX + 1] = {
201 	[TIPC_NLA_PROP_UNSPEC]		= { .type = NLA_UNSPEC },
202 	[TIPC_NLA_PROP_PRIO]		= { .type = NLA_U32 },
203 	[TIPC_NLA_PROP_TOL]		= { .type = NLA_U32 },
204 	[TIPC_NLA_PROP_WIN]		= { .type = NLA_U32 }
205 };
206 
207 /* Send states for broadcast NACKs
208  */
209 enum {
210 	BC_NACK_SND_CONDITIONAL,
211 	BC_NACK_SND_UNCONDITIONAL,
212 	BC_NACK_SND_SUPPRESS,
213 };
214 
215 /*
216  * Interval between NACKs when packets arrive out of order
217  */
218 #define TIPC_NACK_INTV (TIPC_MIN_LINK_WIN * 2)
219 /*
220  * Out-of-range value for link session numbers
221  */
222 #define WILDCARD_SESSION 0x10000
223 
224 /* Link FSM states:
225  */
226 enum {
227 	LINK_ESTABLISHED     = 0xe,
228 	LINK_ESTABLISHING    = 0xe  << 4,
229 	LINK_RESET           = 0x1  << 8,
230 	LINK_RESETTING       = 0x2  << 12,
231 	LINK_PEER_RESET      = 0xd  << 16,
232 	LINK_FAILINGOVER     = 0xf  << 20,
233 	LINK_SYNCHING        = 0xc  << 24
234 };
235 
236 /* Link FSM state checking routines
237  */
238 static int link_is_up(struct tipc_link *l)
239 {
240 	return l->state & (LINK_ESTABLISHED | LINK_SYNCHING);
241 }
242 
243 static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
244 			       struct sk_buff_head *xmitq);
245 static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
246 				      u16 rcvgap, int tolerance, int priority,
247 				      struct sk_buff_head *xmitq);
248 static void link_print(struct tipc_link *l, const char *str);
249 static void tipc_link_build_nack_msg(struct tipc_link *l,
250 				     struct sk_buff_head *xmitq);
251 static void tipc_link_build_bc_init_msg(struct tipc_link *l,
252 					struct sk_buff_head *xmitq);
253 static bool tipc_link_release_pkts(struct tipc_link *l, u16 to);
254 
255 /*
256  *  Simple non-static link routines (i.e. referenced outside this file)
257  */
258 bool tipc_link_is_up(struct tipc_link *l)
259 {
260 	return link_is_up(l);
261 }
262 
263 bool tipc_link_peer_is_down(struct tipc_link *l)
264 {
265 	return l->state == LINK_PEER_RESET;
266 }
267 
268 bool tipc_link_is_reset(struct tipc_link *l)
269 {
270 	return l->state & (LINK_RESET | LINK_FAILINGOVER | LINK_ESTABLISHING);
271 }
272 
273 bool tipc_link_is_establishing(struct tipc_link *l)
274 {
275 	return l->state == LINK_ESTABLISHING;
276 }
277 
278 bool tipc_link_is_synching(struct tipc_link *l)
279 {
280 	return l->state == LINK_SYNCHING;
281 }
282 
283 bool tipc_link_is_failingover(struct tipc_link *l)
284 {
285 	return l->state == LINK_FAILINGOVER;
286 }
287 
288 bool tipc_link_is_blocked(struct tipc_link *l)
289 {
290 	return l->state & (LINK_RESETTING | LINK_PEER_RESET | LINK_FAILINGOVER);
291 }
292 
293 static bool link_is_bc_sndlink(struct tipc_link *l)
294 {
295 	return !l->bc_sndlink;
296 }
297 
298 static bool link_is_bc_rcvlink(struct tipc_link *l)
299 {
300 	return ((l->bc_rcvlink == l) && !link_is_bc_sndlink(l));
301 }
302 
303 int tipc_link_is_active(struct tipc_link *l)
304 {
305 	return l->active;
306 }
307 
308 void tipc_link_set_active(struct tipc_link *l, bool active)
309 {
310 	l->active = active;
311 }
312 
313 u32 tipc_link_id(struct tipc_link *l)
314 {
315 	return l->peer_bearer_id << 16 | l->bearer_id;
316 }
317 
318 int tipc_link_window(struct tipc_link *l)
319 {
320 	return l->window;
321 }
322 
323 int tipc_link_prio(struct tipc_link *l)
324 {
325 	return l->priority;
326 }
327 
328 unsigned long tipc_link_tolerance(struct tipc_link *l)
329 {
330 	return l->tolerance;
331 }
332 
333 struct sk_buff_head *tipc_link_inputq(struct tipc_link *l)
334 {
335 	return l->inputq;
336 }
337 
338 char tipc_link_plane(struct tipc_link *l)
339 {
340 	return l->net_plane;
341 }
342 
343 void tipc_link_add_bc_peer(struct tipc_link *snd_l,
344 			   struct tipc_link *uc_l,
345 			   struct sk_buff_head *xmitq)
346 {
347 	struct tipc_link *rcv_l = uc_l->bc_rcvlink;
348 
349 	snd_l->ackers++;
350 	rcv_l->acked = snd_l->snd_nxt - 1;
351 	snd_l->state = LINK_ESTABLISHED;
352 	tipc_link_build_bc_init_msg(uc_l, xmitq);
353 }
354 
355 void tipc_link_remove_bc_peer(struct tipc_link *snd_l,
356 			      struct tipc_link *rcv_l,
357 			      struct sk_buff_head *xmitq)
358 {
359 	u16 ack = snd_l->snd_nxt - 1;
360 
361 	snd_l->ackers--;
362 	tipc_link_bc_ack_rcv(rcv_l, ack, xmitq);
363 	tipc_link_reset(rcv_l);
364 	rcv_l->state = LINK_RESET;
365 	if (!snd_l->ackers) {
366 		tipc_link_reset(snd_l);
367 		snd_l->state = LINK_RESET;
368 		__skb_queue_purge(xmitq);
369 	}
370 }
371 
372 int tipc_link_bc_peers(struct tipc_link *l)
373 {
374 	return l->ackers;
375 }
376 
377 void tipc_link_set_mtu(struct tipc_link *l, int mtu)
378 {
379 	l->mtu = mtu;
380 }
381 
382 int tipc_link_mtu(struct tipc_link *l)
383 {
384 	return l->mtu;
385 }
386 
387 u16 tipc_link_rcv_nxt(struct tipc_link *l)
388 {
389 	return l->rcv_nxt;
390 }
391 
392 u16 tipc_link_acked(struct tipc_link *l)
393 {
394 	return l->acked;
395 }
396 
397 char *tipc_link_name(struct tipc_link *l)
398 {
399 	return l->name;
400 }
401 
402 static u32 link_own_addr(struct tipc_link *l)
403 {
404 	return msg_prevnode(l->pmsg);
405 }
406 
407 void tipc_link_reinit(struct tipc_link *l, u32 addr)
408 {
409 	msg_set_prevnode(l->pmsg, addr);
410 }
411 
412 /**
413  * tipc_link_create - create a new link
414  * @n: pointer to associated node
415  * @if_name: associated interface name
416  * @bearer_id: id (index) of associated bearer
417  * @tolerance: link tolerance to be used by link
418  * @net_plane: network plane (A,B,c..) this link belongs to
419  * @mtu: mtu to be advertised by link
420  * @priority: priority to be used by link
421  * @window: send window to be used by link
422  * @session: session to be used by link
423  * @ownnode: identity of own node
424  * @peer: node id of peer node
425  * @peer_caps: bitmap describing peer node capabilities
426  * @bc_sndlink: the namespace global link used for broadcast sending
427  * @bc_rcvlink: the peer specific link used for broadcast reception
428  * @inputq: queue to put messages ready for delivery
429  * @namedq: queue to put binding table update messages ready for delivery
430  * @link: return value, pointer to put the created link
431  *
432  * Returns true if link was created, otherwise false
433  */
434 bool tipc_link_create(struct net *net, char *if_name, int bearer_id,
435 		      int tolerance, char net_plane, u32 mtu, int priority,
436 		      int window, u32 session, u32 ownnode, u32 peer,
437 		      u16 peer_caps,
438 		      struct tipc_link *bc_sndlink,
439 		      struct tipc_link *bc_rcvlink,
440 		      struct sk_buff_head *inputq,
441 		      struct sk_buff_head *namedq,
442 		      struct tipc_link **link)
443 {
444 	struct tipc_link *l;
445 	struct tipc_msg *hdr;
446 
447 	l = kzalloc(sizeof(*l), GFP_ATOMIC);
448 	if (!l)
449 		return false;
450 	*link = l;
451 	l->pmsg = (struct tipc_msg *)&l->proto_msg;
452 	hdr = l->pmsg;
453 	tipc_msg_init(ownnode, hdr, LINK_PROTOCOL, RESET_MSG, INT_H_SIZE, peer);
454 	msg_set_size(hdr, sizeof(l->proto_msg));
455 	msg_set_session(hdr, session);
456 	msg_set_bearer_id(hdr, l->bearer_id);
457 
458 	/* Note: peer i/f name is completed by reset/activate message */
459 	sprintf(l->name, "%u.%u.%u:%s-%u.%u.%u:unknown",
460 		tipc_zone(ownnode), tipc_cluster(ownnode), tipc_node(ownnode),
461 		if_name, tipc_zone(peer), tipc_cluster(peer), tipc_node(peer));
462 	strcpy((char *)msg_data(hdr), if_name);
463 
464 	l->addr = peer;
465 	l->peer_caps = peer_caps;
466 	l->net = net;
467 	l->peer_session = WILDCARD_SESSION;
468 	l->bearer_id = bearer_id;
469 	l->tolerance = tolerance;
470 	l->net_plane = net_plane;
471 	l->advertised_mtu = mtu;
472 	l->mtu = mtu;
473 	l->priority = priority;
474 	tipc_link_set_queue_limits(l, window);
475 	l->ackers = 1;
476 	l->bc_sndlink = bc_sndlink;
477 	l->bc_rcvlink = bc_rcvlink;
478 	l->inputq = inputq;
479 	l->namedq = namedq;
480 	l->state = LINK_RESETTING;
481 	__skb_queue_head_init(&l->transmq);
482 	__skb_queue_head_init(&l->backlogq);
483 	__skb_queue_head_init(&l->deferdq);
484 	skb_queue_head_init(&l->wakeupq);
485 	skb_queue_head_init(l->inputq);
486 	return true;
487 }
488 
489 /**
490  * tipc_link_bc_create - create new link to be used for broadcast
491  * @n: pointer to associated node
492  * @mtu: mtu to be used
493  * @window: send window to be used
494  * @inputq: queue to put messages ready for delivery
495  * @namedq: queue to put binding table update messages ready for delivery
496  * @link: return value, pointer to put the created link
497  *
498  * Returns true if link was created, otherwise false
499  */
500 bool tipc_link_bc_create(struct net *net, u32 ownnode, u32 peer,
501 			 int mtu, int window, u16 peer_caps,
502 			 struct sk_buff_head *inputq,
503 			 struct sk_buff_head *namedq,
504 			 struct tipc_link *bc_sndlink,
505 			 struct tipc_link **link)
506 {
507 	struct tipc_link *l;
508 
509 	if (!tipc_link_create(net, "", MAX_BEARERS, 0, 'Z', mtu, 0, window,
510 			      0, ownnode, peer, peer_caps, bc_sndlink,
511 			      NULL, inputq, namedq, link))
512 		return false;
513 
514 	l = *link;
515 	strcpy(l->name, tipc_bclink_name);
516 	tipc_link_reset(l);
517 	l->state = LINK_RESET;
518 	l->ackers = 0;
519 	l->bc_rcvlink = l;
520 
521 	/* Broadcast send link is always up */
522 	if (link_is_bc_sndlink(l))
523 		l->state = LINK_ESTABLISHED;
524 
525 	return true;
526 }
527 
528 /**
529  * tipc_link_fsm_evt - link finite state machine
530  * @l: pointer to link
531  * @evt: state machine event to be processed
532  */
533 int tipc_link_fsm_evt(struct tipc_link *l, int evt)
534 {
535 	int rc = 0;
536 
537 	switch (l->state) {
538 	case LINK_RESETTING:
539 		switch (evt) {
540 		case LINK_PEER_RESET_EVT:
541 			l->state = LINK_PEER_RESET;
542 			break;
543 		case LINK_RESET_EVT:
544 			l->state = LINK_RESET;
545 			break;
546 		case LINK_FAILURE_EVT:
547 		case LINK_FAILOVER_BEGIN_EVT:
548 		case LINK_ESTABLISH_EVT:
549 		case LINK_FAILOVER_END_EVT:
550 		case LINK_SYNCH_BEGIN_EVT:
551 		case LINK_SYNCH_END_EVT:
552 		default:
553 			goto illegal_evt;
554 		}
555 		break;
556 	case LINK_RESET:
557 		switch (evt) {
558 		case LINK_PEER_RESET_EVT:
559 			l->state = LINK_ESTABLISHING;
560 			break;
561 		case LINK_FAILOVER_BEGIN_EVT:
562 			l->state = LINK_FAILINGOVER;
563 		case LINK_FAILURE_EVT:
564 		case LINK_RESET_EVT:
565 		case LINK_ESTABLISH_EVT:
566 		case LINK_FAILOVER_END_EVT:
567 			break;
568 		case LINK_SYNCH_BEGIN_EVT:
569 		case LINK_SYNCH_END_EVT:
570 		default:
571 			goto illegal_evt;
572 		}
573 		break;
574 	case LINK_PEER_RESET:
575 		switch (evt) {
576 		case LINK_RESET_EVT:
577 			l->state = LINK_ESTABLISHING;
578 			break;
579 		case LINK_PEER_RESET_EVT:
580 		case LINK_ESTABLISH_EVT:
581 		case LINK_FAILURE_EVT:
582 			break;
583 		case LINK_SYNCH_BEGIN_EVT:
584 		case LINK_SYNCH_END_EVT:
585 		case LINK_FAILOVER_BEGIN_EVT:
586 		case LINK_FAILOVER_END_EVT:
587 		default:
588 			goto illegal_evt;
589 		}
590 		break;
591 	case LINK_FAILINGOVER:
592 		switch (evt) {
593 		case LINK_FAILOVER_END_EVT:
594 			l->state = LINK_RESET;
595 			break;
596 		case LINK_PEER_RESET_EVT:
597 		case LINK_RESET_EVT:
598 		case LINK_ESTABLISH_EVT:
599 		case LINK_FAILURE_EVT:
600 			break;
601 		case LINK_FAILOVER_BEGIN_EVT:
602 		case LINK_SYNCH_BEGIN_EVT:
603 		case LINK_SYNCH_END_EVT:
604 		default:
605 			goto illegal_evt;
606 		}
607 		break;
608 	case LINK_ESTABLISHING:
609 		switch (evt) {
610 		case LINK_ESTABLISH_EVT:
611 			l->state = LINK_ESTABLISHED;
612 			break;
613 		case LINK_FAILOVER_BEGIN_EVT:
614 			l->state = LINK_FAILINGOVER;
615 			break;
616 		case LINK_RESET_EVT:
617 			l->state = LINK_RESET;
618 			break;
619 		case LINK_FAILURE_EVT:
620 		case LINK_PEER_RESET_EVT:
621 		case LINK_SYNCH_BEGIN_EVT:
622 		case LINK_FAILOVER_END_EVT:
623 			break;
624 		case LINK_SYNCH_END_EVT:
625 		default:
626 			goto illegal_evt;
627 		}
628 		break;
629 	case LINK_ESTABLISHED:
630 		switch (evt) {
631 		case LINK_PEER_RESET_EVT:
632 			l->state = LINK_PEER_RESET;
633 			rc |= TIPC_LINK_DOWN_EVT;
634 			break;
635 		case LINK_FAILURE_EVT:
636 			l->state = LINK_RESETTING;
637 			rc |= TIPC_LINK_DOWN_EVT;
638 			break;
639 		case LINK_RESET_EVT:
640 			l->state = LINK_RESET;
641 			break;
642 		case LINK_ESTABLISH_EVT:
643 		case LINK_SYNCH_END_EVT:
644 			break;
645 		case LINK_SYNCH_BEGIN_EVT:
646 			l->state = LINK_SYNCHING;
647 			break;
648 		case LINK_FAILOVER_BEGIN_EVT:
649 		case LINK_FAILOVER_END_EVT:
650 		default:
651 			goto illegal_evt;
652 		}
653 		break;
654 	case LINK_SYNCHING:
655 		switch (evt) {
656 		case LINK_PEER_RESET_EVT:
657 			l->state = LINK_PEER_RESET;
658 			rc |= TIPC_LINK_DOWN_EVT;
659 			break;
660 		case LINK_FAILURE_EVT:
661 			l->state = LINK_RESETTING;
662 			rc |= TIPC_LINK_DOWN_EVT;
663 			break;
664 		case LINK_RESET_EVT:
665 			l->state = LINK_RESET;
666 			break;
667 		case LINK_ESTABLISH_EVT:
668 		case LINK_SYNCH_BEGIN_EVT:
669 			break;
670 		case LINK_SYNCH_END_EVT:
671 			l->state = LINK_ESTABLISHED;
672 			break;
673 		case LINK_FAILOVER_BEGIN_EVT:
674 		case LINK_FAILOVER_END_EVT:
675 		default:
676 			goto illegal_evt;
677 		}
678 		break;
679 	default:
680 		pr_err("Unknown FSM state %x in %s\n", l->state, l->name);
681 	}
682 	return rc;
683 illegal_evt:
684 	pr_err("Illegal FSM event %x in state %x on link %s\n",
685 	       evt, l->state, l->name);
686 	return rc;
687 }
688 
689 /* link_profile_stats - update statistical profiling of traffic
690  */
691 static void link_profile_stats(struct tipc_link *l)
692 {
693 	struct sk_buff *skb;
694 	struct tipc_msg *msg;
695 	int length;
696 
697 	/* Update counters used in statistical profiling of send traffic */
698 	l->stats.accu_queue_sz += skb_queue_len(&l->transmq);
699 	l->stats.queue_sz_counts++;
700 
701 	skb = skb_peek(&l->transmq);
702 	if (!skb)
703 		return;
704 	msg = buf_msg(skb);
705 	length = msg_size(msg);
706 
707 	if (msg_user(msg) == MSG_FRAGMENTER) {
708 		if (msg_type(msg) != FIRST_FRAGMENT)
709 			return;
710 		length = msg_size(msg_get_wrapped(msg));
711 	}
712 	l->stats.msg_lengths_total += length;
713 	l->stats.msg_length_counts++;
714 	if (length <= 64)
715 		l->stats.msg_length_profile[0]++;
716 	else if (length <= 256)
717 		l->stats.msg_length_profile[1]++;
718 	else if (length <= 1024)
719 		l->stats.msg_length_profile[2]++;
720 	else if (length <= 4096)
721 		l->stats.msg_length_profile[3]++;
722 	else if (length <= 16384)
723 		l->stats.msg_length_profile[4]++;
724 	else if (length <= 32768)
725 		l->stats.msg_length_profile[5]++;
726 	else
727 		l->stats.msg_length_profile[6]++;
728 }
729 
730 /* tipc_link_timeout - perform periodic task as instructed from node timeout
731  */
732 /* tipc_link_timeout - perform periodic task as instructed from node timeout
733  */
734 int tipc_link_timeout(struct tipc_link *l, struct sk_buff_head *xmitq)
735 {
736 	int rc = 0;
737 	int mtyp = STATE_MSG;
738 	bool xmit = false;
739 	bool prb = false;
740 	u16 bc_snt = l->bc_sndlink->snd_nxt - 1;
741 	u16 bc_acked = l->bc_rcvlink->acked;
742 	bool bc_up = link_is_up(l->bc_rcvlink);
743 
744 	link_profile_stats(l);
745 
746 	switch (l->state) {
747 	case LINK_ESTABLISHED:
748 	case LINK_SYNCHING:
749 		if (!l->silent_intv_cnt) {
750 			if (bc_up && (bc_acked != bc_snt))
751 				xmit = true;
752 		} else if (l->silent_intv_cnt <= l->abort_limit) {
753 			xmit = true;
754 			prb = true;
755 		} else {
756 			rc |= tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
757 		}
758 		l->silent_intv_cnt++;
759 		break;
760 	case LINK_RESET:
761 		xmit = true;
762 		mtyp = RESET_MSG;
763 		break;
764 	case LINK_ESTABLISHING:
765 		xmit = true;
766 		mtyp = ACTIVATE_MSG;
767 		break;
768 	case LINK_PEER_RESET:
769 	case LINK_RESETTING:
770 	case LINK_FAILINGOVER:
771 		break;
772 	default:
773 		break;
774 	}
775 
776 	if (xmit)
777 		tipc_link_build_proto_msg(l, mtyp, prb, 0, 0, 0, xmitq);
778 
779 	return rc;
780 }
781 
782 /**
783  * link_schedule_user - schedule a message sender for wakeup after congestion
784  * @link: congested link
785  * @list: message that was attempted sent
786  * Create pseudo msg to send back to user when congestion abates
787  * Does not consume buffer list
788  */
789 static int link_schedule_user(struct tipc_link *link, struct sk_buff_head *list)
790 {
791 	struct tipc_msg *msg = buf_msg(skb_peek(list));
792 	int imp = msg_importance(msg);
793 	u32 oport = msg_origport(msg);
794 	u32 addr = link_own_addr(link);
795 	struct sk_buff *skb;
796 
797 	/* This really cannot happen...  */
798 	if (unlikely(imp > TIPC_CRITICAL_IMPORTANCE)) {
799 		pr_warn("%s<%s>, send queue full", link_rst_msg, link->name);
800 		return -ENOBUFS;
801 	}
802 	/* Non-blocking sender: */
803 	if (TIPC_SKB_CB(skb_peek(list))->wakeup_pending)
804 		return -ELINKCONG;
805 
806 	/* Create and schedule wakeup pseudo message */
807 	skb = tipc_msg_create(SOCK_WAKEUP, 0, INT_H_SIZE, 0,
808 			      addr, addr, oport, 0, 0);
809 	if (!skb)
810 		return -ENOBUFS;
811 	TIPC_SKB_CB(skb)->chain_sz = skb_queue_len(list);
812 	TIPC_SKB_CB(skb)->chain_imp = imp;
813 	skb_queue_tail(&link->wakeupq, skb);
814 	link->stats.link_congs++;
815 	return -ELINKCONG;
816 }
817 
818 /**
819  * link_prepare_wakeup - prepare users for wakeup after congestion
820  * @link: congested link
821  * Move a number of waiting users, as permitted by available space in
822  * the send queue, from link wait queue to node wait queue for wakeup
823  */
824 void link_prepare_wakeup(struct tipc_link *l)
825 {
826 	int pnd[TIPC_SYSTEM_IMPORTANCE + 1] = {0,};
827 	int imp, lim;
828 	struct sk_buff *skb, *tmp;
829 
830 	skb_queue_walk_safe(&l->wakeupq, skb, tmp) {
831 		imp = TIPC_SKB_CB(skb)->chain_imp;
832 		lim = l->window + l->backlog[imp].limit;
833 		pnd[imp] += TIPC_SKB_CB(skb)->chain_sz;
834 		if ((pnd[imp] + l->backlog[imp].len) >= lim)
835 			break;
836 		skb_unlink(skb, &l->wakeupq);
837 		skb_queue_tail(l->inputq, skb);
838 	}
839 }
840 
841 void tipc_link_reset(struct tipc_link *l)
842 {
843 	/* Link is down, accept any session */
844 	l->peer_session = WILDCARD_SESSION;
845 
846 	/* If peer is up, it only accepts an incremented session number */
847 	msg_set_session(l->pmsg, msg_session(l->pmsg) + 1);
848 
849 	/* Prepare for renewed mtu size negotiation */
850 	l->mtu = l->advertised_mtu;
851 
852 	/* Clean up all queues and counters: */
853 	__skb_queue_purge(&l->transmq);
854 	__skb_queue_purge(&l->deferdq);
855 	skb_queue_splice_init(&l->wakeupq, l->inputq);
856 	__skb_queue_purge(&l->backlogq);
857 	l->backlog[TIPC_LOW_IMPORTANCE].len = 0;
858 	l->backlog[TIPC_MEDIUM_IMPORTANCE].len = 0;
859 	l->backlog[TIPC_HIGH_IMPORTANCE].len = 0;
860 	l->backlog[TIPC_CRITICAL_IMPORTANCE].len = 0;
861 	l->backlog[TIPC_SYSTEM_IMPORTANCE].len = 0;
862 	kfree_skb(l->reasm_buf);
863 	kfree_skb(l->failover_reasm_skb);
864 	l->reasm_buf = NULL;
865 	l->failover_reasm_skb = NULL;
866 	l->rcv_unacked = 0;
867 	l->snd_nxt = 1;
868 	l->rcv_nxt = 1;
869 	l->acked = 0;
870 	l->silent_intv_cnt = 0;
871 	l->stats.recv_info = 0;
872 	l->stale_count = 0;
873 	l->bc_peer_is_up = false;
874 	tipc_link_reset_stats(l);
875 }
876 
877 /**
878  * tipc_link_xmit(): enqueue buffer list according to queue situation
879  * @link: link to use
880  * @list: chain of buffers containing message
881  * @xmitq: returned list of packets to be sent by caller
882  *
883  * Consumes the buffer chain, except when returning -ELINKCONG,
884  * since the caller then may want to make more send attempts.
885  * Returns 0 if success, or errno: -ELINKCONG, -EMSGSIZE or -ENOBUFS
886  * Messages at TIPC_SYSTEM_IMPORTANCE are always accepted
887  */
888 int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *list,
889 		   struct sk_buff_head *xmitq)
890 {
891 	struct tipc_msg *hdr = buf_msg(skb_peek(list));
892 	unsigned int maxwin = l->window;
893 	unsigned int i, imp = msg_importance(hdr);
894 	unsigned int mtu = l->mtu;
895 	u16 ack = l->rcv_nxt - 1;
896 	u16 seqno = l->snd_nxt;
897 	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
898 	struct sk_buff_head *transmq = &l->transmq;
899 	struct sk_buff_head *backlogq = &l->backlogq;
900 	struct sk_buff *skb, *_skb, *bskb;
901 
902 	/* Match msg importance against this and all higher backlog limits: */
903 	for (i = imp; i <= TIPC_SYSTEM_IMPORTANCE; i++) {
904 		if (unlikely(l->backlog[i].len >= l->backlog[i].limit))
905 			return link_schedule_user(l, list);
906 	}
907 	if (unlikely(msg_size(hdr) > mtu))
908 		return -EMSGSIZE;
909 
910 	/* Prepare each packet for sending, and add to relevant queue: */
911 	while (skb_queue_len(list)) {
912 		skb = skb_peek(list);
913 		hdr = buf_msg(skb);
914 		msg_set_seqno(hdr, seqno);
915 		msg_set_ack(hdr, ack);
916 		msg_set_bcast_ack(hdr, bc_ack);
917 
918 		if (likely(skb_queue_len(transmq) < maxwin)) {
919 			_skb = skb_clone(skb, GFP_ATOMIC);
920 			if (!_skb)
921 				return -ENOBUFS;
922 			__skb_dequeue(list);
923 			__skb_queue_tail(transmq, skb);
924 			__skb_queue_tail(xmitq, _skb);
925 			TIPC_SKB_CB(skb)->ackers = l->ackers;
926 			l->rcv_unacked = 0;
927 			seqno++;
928 			continue;
929 		}
930 		if (tipc_msg_bundle(skb_peek_tail(backlogq), hdr, mtu)) {
931 			kfree_skb(__skb_dequeue(list));
932 			l->stats.sent_bundled++;
933 			continue;
934 		}
935 		if (tipc_msg_make_bundle(&bskb, hdr, mtu, l->addr)) {
936 			kfree_skb(__skb_dequeue(list));
937 			__skb_queue_tail(backlogq, bskb);
938 			l->backlog[msg_importance(buf_msg(bskb))].len++;
939 			l->stats.sent_bundled++;
940 			l->stats.sent_bundles++;
941 			continue;
942 		}
943 		l->backlog[imp].len += skb_queue_len(list);
944 		skb_queue_splice_tail_init(list, backlogq);
945 	}
946 	l->snd_nxt = seqno;
947 	return 0;
948 }
949 
950 void tipc_link_advance_backlog(struct tipc_link *l, struct sk_buff_head *xmitq)
951 {
952 	struct sk_buff *skb, *_skb;
953 	struct tipc_msg *hdr;
954 	u16 seqno = l->snd_nxt;
955 	u16 ack = l->rcv_nxt - 1;
956 	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
957 
958 	while (skb_queue_len(&l->transmq) < l->window) {
959 		skb = skb_peek(&l->backlogq);
960 		if (!skb)
961 			break;
962 		_skb = skb_clone(skb, GFP_ATOMIC);
963 		if (!_skb)
964 			break;
965 		__skb_dequeue(&l->backlogq);
966 		hdr = buf_msg(skb);
967 		l->backlog[msg_importance(hdr)].len--;
968 		__skb_queue_tail(&l->transmq, skb);
969 		__skb_queue_tail(xmitq, _skb);
970 		TIPC_SKB_CB(skb)->ackers = l->ackers;
971 		msg_set_seqno(hdr, seqno);
972 		msg_set_ack(hdr, ack);
973 		msg_set_bcast_ack(hdr, bc_ack);
974 		l->rcv_unacked = 0;
975 		seqno++;
976 	}
977 	l->snd_nxt = seqno;
978 }
979 
980 static void link_retransmit_failure(struct tipc_link *l, struct sk_buff *skb)
981 {
982 	struct tipc_msg *hdr = buf_msg(skb);
983 
984 	pr_warn("Retransmission failure on link <%s>\n", l->name);
985 	link_print(l, "Resetting link ");
986 	pr_info("Failed msg: usr %u, typ %u, len %u, err %u\n",
987 		msg_user(hdr), msg_type(hdr), msg_size(hdr), msg_errcode(hdr));
988 	pr_info("sqno %u, prev: %x, src: %x\n",
989 		msg_seqno(hdr), msg_prevnode(hdr), msg_orignode(hdr));
990 }
991 
992 int tipc_link_retrans(struct tipc_link *l, u16 from, u16 to,
993 		      struct sk_buff_head *xmitq)
994 {
995 	struct sk_buff *_skb, *skb = skb_peek(&l->transmq);
996 	struct tipc_msg *hdr;
997 	u16 ack = l->rcv_nxt - 1;
998 	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
999 
1000 	if (!skb)
1001 		return 0;
1002 
1003 	/* Detect repeated retransmit failures on same packet */
1004 	if (likely(l->last_retransm != buf_seqno(skb))) {
1005 		l->last_retransm = buf_seqno(skb);
1006 		l->stale_count = 1;
1007 	} else if (++l->stale_count > 100) {
1008 		link_retransmit_failure(l, skb);
1009 		return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1010 	}
1011 
1012 	/* Move forward to where retransmission should start */
1013 	skb_queue_walk(&l->transmq, skb) {
1014 		if (!less(buf_seqno(skb), from))
1015 			break;
1016 	}
1017 
1018 	skb_queue_walk_from(&l->transmq, skb) {
1019 		if (more(buf_seqno(skb), to))
1020 			break;
1021 		hdr = buf_msg(skb);
1022 		_skb = __pskb_copy(skb, MIN_H_SIZE, GFP_ATOMIC);
1023 		if (!_skb)
1024 			return 0;
1025 		hdr = buf_msg(_skb);
1026 		msg_set_ack(hdr, ack);
1027 		msg_set_bcast_ack(hdr, bc_ack);
1028 		_skb->priority = TC_PRIO_CONTROL;
1029 		__skb_queue_tail(xmitq, _skb);
1030 		l->stats.retransmitted++;
1031 	}
1032 	return 0;
1033 }
1034 
1035 /* tipc_data_input - deliver data and name distr msgs to upper layer
1036  *
1037  * Consumes buffer if message is of right type
1038  * Node lock must be held
1039  */
1040 static bool tipc_data_input(struct tipc_link *l, struct sk_buff *skb,
1041 			    struct sk_buff_head *inputq)
1042 {
1043 	switch (msg_user(buf_msg(skb))) {
1044 	case TIPC_LOW_IMPORTANCE:
1045 	case TIPC_MEDIUM_IMPORTANCE:
1046 	case TIPC_HIGH_IMPORTANCE:
1047 	case TIPC_CRITICAL_IMPORTANCE:
1048 	case CONN_MANAGER:
1049 		skb_queue_tail(inputq, skb);
1050 		return true;
1051 	case NAME_DISTRIBUTOR:
1052 		l->bc_rcvlink->state = LINK_ESTABLISHED;
1053 		skb_queue_tail(l->namedq, skb);
1054 		return true;
1055 	case MSG_BUNDLER:
1056 	case TUNNEL_PROTOCOL:
1057 	case MSG_FRAGMENTER:
1058 	case BCAST_PROTOCOL:
1059 		return false;
1060 	default:
1061 		pr_warn("Dropping received illegal msg type\n");
1062 		kfree_skb(skb);
1063 		return false;
1064 	};
1065 }
1066 
1067 /* tipc_link_input - process packet that has passed link protocol check
1068  *
1069  * Consumes buffer
1070  */
1071 static int tipc_link_input(struct tipc_link *l, struct sk_buff *skb,
1072 			   struct sk_buff_head *inputq)
1073 {
1074 	struct tipc_msg *hdr = buf_msg(skb);
1075 	struct sk_buff **reasm_skb = &l->reasm_buf;
1076 	struct sk_buff *iskb;
1077 	struct sk_buff_head tmpq;
1078 	int usr = msg_user(hdr);
1079 	int rc = 0;
1080 	int pos = 0;
1081 	int ipos = 0;
1082 
1083 	if (unlikely(usr == TUNNEL_PROTOCOL)) {
1084 		if (msg_type(hdr) == SYNCH_MSG) {
1085 			__skb_queue_purge(&l->deferdq);
1086 			goto drop;
1087 		}
1088 		if (!tipc_msg_extract(skb, &iskb, &ipos))
1089 			return rc;
1090 		kfree_skb(skb);
1091 		skb = iskb;
1092 		hdr = buf_msg(skb);
1093 		if (less(msg_seqno(hdr), l->drop_point))
1094 			goto drop;
1095 		if (tipc_data_input(l, skb, inputq))
1096 			return rc;
1097 		usr = msg_user(hdr);
1098 		reasm_skb = &l->failover_reasm_skb;
1099 	}
1100 
1101 	if (usr == MSG_BUNDLER) {
1102 		skb_queue_head_init(&tmpq);
1103 		l->stats.recv_bundles++;
1104 		l->stats.recv_bundled += msg_msgcnt(hdr);
1105 		while (tipc_msg_extract(skb, &iskb, &pos))
1106 			tipc_data_input(l, iskb, &tmpq);
1107 		tipc_skb_queue_splice_tail(&tmpq, inputq);
1108 		return 0;
1109 	} else if (usr == MSG_FRAGMENTER) {
1110 		l->stats.recv_fragments++;
1111 		if (tipc_buf_append(reasm_skb, &skb)) {
1112 			l->stats.recv_fragmented++;
1113 			tipc_data_input(l, skb, inputq);
1114 		} else if (!*reasm_skb && !link_is_bc_rcvlink(l)) {
1115 			pr_warn_ratelimited("Unable to build fragment list\n");
1116 			return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1117 		}
1118 		return 0;
1119 	} else if (usr == BCAST_PROTOCOL) {
1120 		tipc_bcast_lock(l->net);
1121 		tipc_link_bc_init_rcv(l->bc_rcvlink, hdr);
1122 		tipc_bcast_unlock(l->net);
1123 	}
1124 drop:
1125 	kfree_skb(skb);
1126 	return 0;
1127 }
1128 
1129 static bool tipc_link_release_pkts(struct tipc_link *l, u16 acked)
1130 {
1131 	bool released = false;
1132 	struct sk_buff *skb, *tmp;
1133 
1134 	skb_queue_walk_safe(&l->transmq, skb, tmp) {
1135 		if (more(buf_seqno(skb), acked))
1136 			break;
1137 		__skb_unlink(skb, &l->transmq);
1138 		kfree_skb(skb);
1139 		released = true;
1140 	}
1141 	return released;
1142 }
1143 
1144 /* tipc_link_build_ack_msg: prepare link acknowledge message for transmission
1145  *
1146  * Note that sending of broadcast ack is coordinated among nodes, to reduce
1147  * risk of ack storms towards the sender
1148  */
1149 int tipc_link_build_ack_msg(struct tipc_link *l, struct sk_buff_head *xmitq)
1150 {
1151 	if (!l)
1152 		return 0;
1153 
1154 	/* Broadcast ACK must be sent via a unicast link => defer to caller */
1155 	if (link_is_bc_rcvlink(l)) {
1156 		if (((l->rcv_nxt ^ link_own_addr(l)) & 0xf) != 0xf)
1157 			return 0;
1158 		l->rcv_unacked = 0;
1159 		return TIPC_LINK_SND_BC_ACK;
1160 	}
1161 
1162 	/* Unicast ACK */
1163 	l->rcv_unacked = 0;
1164 	l->stats.sent_acks++;
1165 	tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, 0, xmitq);
1166 	return 0;
1167 }
1168 
1169 /* tipc_link_build_reset_msg: prepare link RESET or ACTIVATE message
1170  */
1171 void tipc_link_build_reset_msg(struct tipc_link *l, struct sk_buff_head *xmitq)
1172 {
1173 	int mtyp = RESET_MSG;
1174 
1175 	if (l->state == LINK_ESTABLISHING)
1176 		mtyp = ACTIVATE_MSG;
1177 
1178 	tipc_link_build_proto_msg(l, mtyp, 0, 0, 0, 0, xmitq);
1179 }
1180 
1181 /* tipc_link_build_nack_msg: prepare link nack message for transmission
1182  */
1183 static void tipc_link_build_nack_msg(struct tipc_link *l,
1184 				     struct sk_buff_head *xmitq)
1185 {
1186 	u32 def_cnt = ++l->stats.deferred_recv;
1187 
1188 	if (link_is_bc_rcvlink(l))
1189 		return;
1190 
1191 	if ((skb_queue_len(&l->deferdq) == 1) || !(def_cnt % TIPC_NACK_INTV))
1192 		tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, 0, xmitq);
1193 }
1194 
1195 /* tipc_link_rcv - process TIPC packets/messages arriving from off-node
1196  * @l: the link that should handle the message
1197  * @skb: TIPC packet
1198  * @xmitq: queue to place packets to be sent after this call
1199  */
1200 int tipc_link_rcv(struct tipc_link *l, struct sk_buff *skb,
1201 		  struct sk_buff_head *xmitq)
1202 {
1203 	struct sk_buff_head *defq = &l->deferdq;
1204 	struct tipc_msg *hdr;
1205 	u16 seqno, rcv_nxt, win_lim;
1206 	int rc = 0;
1207 
1208 	do {
1209 		hdr = buf_msg(skb);
1210 		seqno = msg_seqno(hdr);
1211 		rcv_nxt = l->rcv_nxt;
1212 		win_lim = rcv_nxt + TIPC_MAX_LINK_WIN;
1213 
1214 		/* Verify and update link state */
1215 		if (unlikely(msg_user(hdr) == LINK_PROTOCOL))
1216 			return tipc_link_proto_rcv(l, skb, xmitq);
1217 
1218 		if (unlikely(!link_is_up(l))) {
1219 			if (l->state == LINK_ESTABLISHING)
1220 				rc = TIPC_LINK_UP_EVT;
1221 			goto drop;
1222 		}
1223 
1224 		/* Don't send probe at next timeout expiration */
1225 		l->silent_intv_cnt = 0;
1226 
1227 		/* Drop if outside receive window */
1228 		if (unlikely(less(seqno, rcv_nxt) || more(seqno, win_lim))) {
1229 			l->stats.duplicates++;
1230 			goto drop;
1231 		}
1232 
1233 		/* Forward queues and wake up waiting users */
1234 		if (likely(tipc_link_release_pkts(l, msg_ack(hdr)))) {
1235 			tipc_link_advance_backlog(l, xmitq);
1236 			if (unlikely(!skb_queue_empty(&l->wakeupq)))
1237 				link_prepare_wakeup(l);
1238 		}
1239 
1240 		/* Defer delivery if sequence gap */
1241 		if (unlikely(seqno != rcv_nxt)) {
1242 			__tipc_skb_queue_sorted(defq, seqno, skb);
1243 			tipc_link_build_nack_msg(l, xmitq);
1244 			break;
1245 		}
1246 
1247 		/* Deliver packet */
1248 		l->rcv_nxt++;
1249 		l->stats.recv_info++;
1250 		if (!tipc_data_input(l, skb, l->inputq))
1251 			rc |= tipc_link_input(l, skb, l->inputq);
1252 		if (unlikely(++l->rcv_unacked >= TIPC_MIN_LINK_WIN))
1253 			rc |= tipc_link_build_ack_msg(l, xmitq);
1254 		if (unlikely(rc & ~TIPC_LINK_SND_BC_ACK))
1255 			break;
1256 	} while ((skb = __skb_dequeue(defq)));
1257 
1258 	return rc;
1259 drop:
1260 	kfree_skb(skb);
1261 	return rc;
1262 }
1263 
1264 /*
1265  * Send protocol message to the other endpoint.
1266  */
1267 static void tipc_link_proto_xmit(struct tipc_link *l, u32 msg_typ,
1268 				 int probe_msg, u32 gap, u32 tolerance,
1269 				 u32 priority)
1270 {
1271 	struct sk_buff *skb = NULL;
1272 	struct sk_buff_head xmitq;
1273 
1274 	__skb_queue_head_init(&xmitq);
1275 	tipc_link_build_proto_msg(l, msg_typ, probe_msg, gap,
1276 				  tolerance, priority, &xmitq);
1277 	skb = __skb_dequeue(&xmitq);
1278 	if (!skb)
1279 		return;
1280 	tipc_bearer_xmit_skb(l->net, l->bearer_id, skb, l->media_addr);
1281 	l->rcv_unacked = 0;
1282 }
1283 
1284 static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
1285 				      u16 rcvgap, int tolerance, int priority,
1286 				      struct sk_buff_head *xmitq)
1287 {
1288 	struct sk_buff *skb = NULL;
1289 	struct tipc_msg *hdr = l->pmsg;
1290 	bool node_up = link_is_up(l->bc_rcvlink);
1291 
1292 	/* Don't send protocol message during reset or link failover */
1293 	if (tipc_link_is_blocked(l))
1294 		return;
1295 
1296 	msg_set_type(hdr, mtyp);
1297 	msg_set_net_plane(hdr, l->net_plane);
1298 	msg_set_next_sent(hdr, l->snd_nxt);
1299 	msg_set_ack(hdr, l->rcv_nxt - 1);
1300 	msg_set_bcast_ack(hdr, l->bc_rcvlink->rcv_nxt - 1);
1301 	msg_set_last_bcast(hdr, l->bc_sndlink->snd_nxt - 1);
1302 	msg_set_link_tolerance(hdr, tolerance);
1303 	msg_set_linkprio(hdr, priority);
1304 	msg_set_redundant_link(hdr, node_up);
1305 	msg_set_seq_gap(hdr, 0);
1306 
1307 	/* Compatibility: created msg must not be in sequence with pkt flow */
1308 	msg_set_seqno(hdr, l->snd_nxt + U16_MAX / 2);
1309 
1310 	if (mtyp == STATE_MSG) {
1311 		if (!tipc_link_is_up(l))
1312 			return;
1313 
1314 		/* Override rcvgap if there are packets in deferred queue */
1315 		if (!skb_queue_empty(&l->deferdq))
1316 			rcvgap = buf_seqno(skb_peek(&l->deferdq)) - l->rcv_nxt;
1317 		if (rcvgap) {
1318 			msg_set_seq_gap(hdr, rcvgap);
1319 			l->stats.sent_nacks++;
1320 		}
1321 		msg_set_probe(hdr, probe);
1322 		if (probe)
1323 			l->stats.sent_probes++;
1324 		l->stats.sent_states++;
1325 		l->rcv_unacked = 0;
1326 	} else {
1327 		/* RESET_MSG or ACTIVATE_MSG */
1328 		msg_set_max_pkt(hdr, l->advertised_mtu);
1329 		msg_set_ack(hdr, l->rcv_nxt - 1);
1330 		msg_set_next_sent(hdr, 1);
1331 	}
1332 	skb = tipc_buf_acquire(msg_size(hdr));
1333 	if (!skb)
1334 		return;
1335 	skb_copy_to_linear_data(skb, hdr, msg_size(hdr));
1336 	skb->priority = TC_PRIO_CONTROL;
1337 	__skb_queue_tail(xmitq, skb);
1338 }
1339 
1340 /* tipc_link_tnl_prepare(): prepare and return a list of tunnel packets
1341  * with contents of the link's transmit and backlog queues.
1342  */
1343 void tipc_link_tnl_prepare(struct tipc_link *l, struct tipc_link *tnl,
1344 			   int mtyp, struct sk_buff_head *xmitq)
1345 {
1346 	struct sk_buff *skb, *tnlskb;
1347 	struct tipc_msg *hdr, tnlhdr;
1348 	struct sk_buff_head *queue = &l->transmq;
1349 	struct sk_buff_head tmpxq, tnlq;
1350 	u16 pktlen, pktcnt, seqno = l->snd_nxt;
1351 
1352 	if (!tnl)
1353 		return;
1354 
1355 	skb_queue_head_init(&tnlq);
1356 	skb_queue_head_init(&tmpxq);
1357 
1358 	/* At least one packet required for safe algorithm => add dummy */
1359 	skb = tipc_msg_create(TIPC_LOW_IMPORTANCE, TIPC_DIRECT_MSG,
1360 			      BASIC_H_SIZE, 0, l->addr, link_own_addr(l),
1361 			      0, 0, TIPC_ERR_NO_PORT);
1362 	if (!skb) {
1363 		pr_warn("%sunable to create tunnel packet\n", link_co_err);
1364 		return;
1365 	}
1366 	skb_queue_tail(&tnlq, skb);
1367 	tipc_link_xmit(l, &tnlq, &tmpxq);
1368 	__skb_queue_purge(&tmpxq);
1369 
1370 	/* Initialize reusable tunnel packet header */
1371 	tipc_msg_init(link_own_addr(l), &tnlhdr, TUNNEL_PROTOCOL,
1372 		      mtyp, INT_H_SIZE, l->addr);
1373 	pktcnt = skb_queue_len(&l->transmq) + skb_queue_len(&l->backlogq);
1374 	msg_set_msgcnt(&tnlhdr, pktcnt);
1375 	msg_set_bearer_id(&tnlhdr, l->peer_bearer_id);
1376 tnl:
1377 	/* Wrap each packet into a tunnel packet */
1378 	skb_queue_walk(queue, skb) {
1379 		hdr = buf_msg(skb);
1380 		if (queue == &l->backlogq)
1381 			msg_set_seqno(hdr, seqno++);
1382 		pktlen = msg_size(hdr);
1383 		msg_set_size(&tnlhdr, pktlen + INT_H_SIZE);
1384 		tnlskb = tipc_buf_acquire(pktlen + INT_H_SIZE);
1385 		if (!tnlskb) {
1386 			pr_warn("%sunable to send packet\n", link_co_err);
1387 			return;
1388 		}
1389 		skb_copy_to_linear_data(tnlskb, &tnlhdr, INT_H_SIZE);
1390 		skb_copy_to_linear_data_offset(tnlskb, INT_H_SIZE, hdr, pktlen);
1391 		__skb_queue_tail(&tnlq, tnlskb);
1392 	}
1393 	if (queue != &l->backlogq) {
1394 		queue = &l->backlogq;
1395 		goto tnl;
1396 	}
1397 
1398 	tipc_link_xmit(tnl, &tnlq, xmitq);
1399 
1400 	if (mtyp == FAILOVER_MSG) {
1401 		tnl->drop_point = l->rcv_nxt;
1402 		tnl->failover_reasm_skb = l->reasm_buf;
1403 		l->reasm_buf = NULL;
1404 	}
1405 }
1406 
1407 /* tipc_link_proto_rcv(): receive link level protocol message :
1408  * Note that network plane id propagates through the network, and may
1409  * change at any time. The node with lowest numerical id determines
1410  * network plane
1411  */
1412 static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
1413 			       struct sk_buff_head *xmitq)
1414 {
1415 	struct tipc_msg *hdr = buf_msg(skb);
1416 	u16 rcvgap = 0;
1417 	u16 ack = msg_ack(hdr);
1418 	u16 gap = msg_seq_gap(hdr);
1419 	u16 peers_snd_nxt =  msg_next_sent(hdr);
1420 	u16 peers_tol = msg_link_tolerance(hdr);
1421 	u16 peers_prio = msg_linkprio(hdr);
1422 	u16 rcv_nxt = l->rcv_nxt;
1423 	int mtyp = msg_type(hdr);
1424 	char *if_name;
1425 	int rc = 0;
1426 
1427 	if (tipc_link_is_blocked(l) || !xmitq)
1428 		goto exit;
1429 
1430 	if (link_own_addr(l) > msg_prevnode(hdr))
1431 		l->net_plane = msg_net_plane(hdr);
1432 
1433 	switch (mtyp) {
1434 	case RESET_MSG:
1435 
1436 		/* Ignore duplicate RESET with old session number */
1437 		if ((less_eq(msg_session(hdr), l->peer_session)) &&
1438 		    (l->peer_session != WILDCARD_SESSION))
1439 			break;
1440 		/* fall thru' */
1441 
1442 	case ACTIVATE_MSG:
1443 		skb_linearize(skb);
1444 		hdr = buf_msg(skb);
1445 
1446 		/* Complete own link name with peer's interface name */
1447 		if_name =  strrchr(l->name, ':') + 1;
1448 		if (sizeof(l->name) - (if_name - l->name) <= TIPC_MAX_IF_NAME)
1449 			break;
1450 		if (msg_data_sz(hdr) < TIPC_MAX_IF_NAME)
1451 			break;
1452 		strncpy(if_name, msg_data(hdr),	TIPC_MAX_IF_NAME);
1453 
1454 		/* Update own tolerance if peer indicates a non-zero value */
1455 		if (in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL))
1456 			l->tolerance = peers_tol;
1457 
1458 		/* Update own priority if peer's priority is higher */
1459 		if (in_range(peers_prio, l->priority + 1, TIPC_MAX_LINK_PRI))
1460 			l->priority = peers_prio;
1461 
1462 		/* ACTIVATE_MSG serves as PEER_RESET if link is already down */
1463 		if ((mtyp == RESET_MSG) || !link_is_up(l))
1464 			rc = tipc_link_fsm_evt(l, LINK_PEER_RESET_EVT);
1465 
1466 		/* ACTIVATE_MSG takes up link if it was already locally reset */
1467 		if ((mtyp == ACTIVATE_MSG) && (l->state == LINK_ESTABLISHING))
1468 			rc = TIPC_LINK_UP_EVT;
1469 
1470 		l->peer_session = msg_session(hdr);
1471 		l->peer_bearer_id = msg_bearer_id(hdr);
1472 		if (l->mtu > msg_max_pkt(hdr))
1473 			l->mtu = msg_max_pkt(hdr);
1474 		break;
1475 
1476 	case STATE_MSG:
1477 
1478 		/* Update own tolerance if peer indicates a non-zero value */
1479 		if (in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL))
1480 			l->tolerance = peers_tol;
1481 
1482 		l->silent_intv_cnt = 0;
1483 		l->stats.recv_states++;
1484 		if (msg_probe(hdr))
1485 			l->stats.recv_probes++;
1486 
1487 		if (!link_is_up(l)) {
1488 			if (l->state == LINK_ESTABLISHING)
1489 				rc = TIPC_LINK_UP_EVT;
1490 			break;
1491 		}
1492 
1493 		/* Send NACK if peer has sent pkts we haven't received yet */
1494 		if (more(peers_snd_nxt, rcv_nxt) && !tipc_link_is_synching(l))
1495 			rcvgap = peers_snd_nxt - l->rcv_nxt;
1496 		if (rcvgap || (msg_probe(hdr)))
1497 			tipc_link_build_proto_msg(l, STATE_MSG, 0, rcvgap,
1498 						  0, 0, xmitq);
1499 		tipc_link_release_pkts(l, ack);
1500 
1501 		/* If NACK, retransmit will now start at right position */
1502 		if (gap) {
1503 			rc = tipc_link_retrans(l, ack + 1, ack + gap, xmitq);
1504 			l->stats.recv_nacks++;
1505 		}
1506 
1507 		tipc_link_advance_backlog(l, xmitq);
1508 		if (unlikely(!skb_queue_empty(&l->wakeupq)))
1509 			link_prepare_wakeup(l);
1510 	}
1511 exit:
1512 	kfree_skb(skb);
1513 	return rc;
1514 }
1515 
1516 /* tipc_link_build_bc_proto_msg() - create broadcast protocol message
1517  */
1518 static bool tipc_link_build_bc_proto_msg(struct tipc_link *l, bool bcast,
1519 					 u16 peers_snd_nxt,
1520 					 struct sk_buff_head *xmitq)
1521 {
1522 	struct sk_buff *skb;
1523 	struct tipc_msg *hdr;
1524 	struct sk_buff *dfrd_skb = skb_peek(&l->deferdq);
1525 	u16 ack = l->rcv_nxt - 1;
1526 	u16 gap_to = peers_snd_nxt - 1;
1527 
1528 	skb = tipc_msg_create(BCAST_PROTOCOL, STATE_MSG, INT_H_SIZE,
1529 			      0, l->addr, link_own_addr(l), 0, 0, 0);
1530 	if (!skb)
1531 		return false;
1532 	hdr = buf_msg(skb);
1533 	msg_set_last_bcast(hdr, l->bc_sndlink->snd_nxt - 1);
1534 	msg_set_bcast_ack(hdr, ack);
1535 	msg_set_bcgap_after(hdr, ack);
1536 	if (dfrd_skb)
1537 		gap_to = buf_seqno(dfrd_skb) - 1;
1538 	msg_set_bcgap_to(hdr, gap_to);
1539 	msg_set_non_seq(hdr, bcast);
1540 	__skb_queue_tail(xmitq, skb);
1541 	return true;
1542 }
1543 
1544 /* tipc_link_build_bc_init_msg() - synchronize broadcast link endpoints.
1545  *
1546  * Give a newly added peer node the sequence number where it should
1547  * start receiving and acking broadcast packets.
1548  */
1549 static void tipc_link_build_bc_init_msg(struct tipc_link *l,
1550 					struct sk_buff_head *xmitq)
1551 {
1552 	struct sk_buff_head list;
1553 
1554 	__skb_queue_head_init(&list);
1555 	if (!tipc_link_build_bc_proto_msg(l->bc_rcvlink, false, 0, &list))
1556 		return;
1557 	tipc_link_xmit(l, &list, xmitq);
1558 }
1559 
1560 /* tipc_link_bc_init_rcv - receive initial broadcast synch data from peer
1561  */
1562 void tipc_link_bc_init_rcv(struct tipc_link *l, struct tipc_msg *hdr)
1563 {
1564 	int mtyp = msg_type(hdr);
1565 	u16 peers_snd_nxt = msg_bc_snd_nxt(hdr);
1566 
1567 	if (link_is_up(l))
1568 		return;
1569 
1570 	if (msg_user(hdr) == BCAST_PROTOCOL) {
1571 		l->rcv_nxt = peers_snd_nxt;
1572 		l->state = LINK_ESTABLISHED;
1573 		return;
1574 	}
1575 
1576 	if (l->peer_caps & TIPC_BCAST_SYNCH)
1577 		return;
1578 
1579 	if (msg_peer_node_is_up(hdr))
1580 		return;
1581 
1582 	/* Compatibility: accept older, less safe initial synch data */
1583 	if ((mtyp == RESET_MSG) || (mtyp == ACTIVATE_MSG))
1584 		l->rcv_nxt = peers_snd_nxt;
1585 }
1586 
1587 /* tipc_link_bc_sync_rcv - update rcv link according to peer's send state
1588  */
1589 void tipc_link_bc_sync_rcv(struct tipc_link *l, struct tipc_msg *hdr,
1590 			   struct sk_buff_head *xmitq)
1591 {
1592 	u16 peers_snd_nxt = msg_bc_snd_nxt(hdr);
1593 
1594 	if (!link_is_up(l))
1595 		return;
1596 
1597 	if (!msg_peer_node_is_up(hdr))
1598 		return;
1599 
1600 	l->bc_peer_is_up = true;
1601 
1602 	/* Ignore if peers_snd_nxt goes beyond receive window */
1603 	if (more(peers_snd_nxt, l->rcv_nxt + l->window))
1604 		return;
1605 
1606 	if (!more(peers_snd_nxt, l->rcv_nxt)) {
1607 		l->nack_state = BC_NACK_SND_CONDITIONAL;
1608 		return;
1609 	}
1610 
1611 	/* Don't NACK if one was recently sent or peeked */
1612 	if (l->nack_state == BC_NACK_SND_SUPPRESS) {
1613 		l->nack_state = BC_NACK_SND_UNCONDITIONAL;
1614 		return;
1615 	}
1616 
1617 	/* Conditionally delay NACK sending until next synch rcv */
1618 	if (l->nack_state == BC_NACK_SND_CONDITIONAL) {
1619 		l->nack_state = BC_NACK_SND_UNCONDITIONAL;
1620 		if ((peers_snd_nxt - l->rcv_nxt) < TIPC_MIN_LINK_WIN)
1621 			return;
1622 	}
1623 
1624 	/* Send NACK now but suppress next one */
1625 	tipc_link_build_bc_proto_msg(l, true, peers_snd_nxt, xmitq);
1626 	l->nack_state = BC_NACK_SND_SUPPRESS;
1627 }
1628 
1629 void tipc_link_bc_ack_rcv(struct tipc_link *l, u16 acked,
1630 			  struct sk_buff_head *xmitq)
1631 {
1632 	struct sk_buff *skb, *tmp;
1633 	struct tipc_link *snd_l = l->bc_sndlink;
1634 
1635 	if (!link_is_up(l) || !l->bc_peer_is_up)
1636 		return;
1637 
1638 	if (!more(acked, l->acked))
1639 		return;
1640 
1641 	/* Skip over packets peer has already acked */
1642 	skb_queue_walk(&snd_l->transmq, skb) {
1643 		if (more(buf_seqno(skb), l->acked))
1644 			break;
1645 	}
1646 
1647 	/* Update/release the packets peer is acking now */
1648 	skb_queue_walk_from_safe(&snd_l->transmq, skb, tmp) {
1649 		if (more(buf_seqno(skb), acked))
1650 			break;
1651 		if (!--TIPC_SKB_CB(skb)->ackers) {
1652 			__skb_unlink(skb, &snd_l->transmq);
1653 			kfree_skb(skb);
1654 		}
1655 	}
1656 	l->acked = acked;
1657 	tipc_link_advance_backlog(snd_l, xmitq);
1658 	if (unlikely(!skb_queue_empty(&snd_l->wakeupq)))
1659 		link_prepare_wakeup(snd_l);
1660 }
1661 
1662 /* tipc_link_bc_nack_rcv(): receive broadcast nack message
1663  */
1664 int tipc_link_bc_nack_rcv(struct tipc_link *l, struct sk_buff *skb,
1665 			  struct sk_buff_head *xmitq)
1666 {
1667 	struct tipc_msg *hdr = buf_msg(skb);
1668 	u32 dnode = msg_destnode(hdr);
1669 	int mtyp = msg_type(hdr);
1670 	u16 acked = msg_bcast_ack(hdr);
1671 	u16 from = acked + 1;
1672 	u16 to = msg_bcgap_to(hdr);
1673 	u16 peers_snd_nxt = to + 1;
1674 	int rc = 0;
1675 
1676 	kfree_skb(skb);
1677 
1678 	if (!tipc_link_is_up(l) || !l->bc_peer_is_up)
1679 		return 0;
1680 
1681 	if (mtyp != STATE_MSG)
1682 		return 0;
1683 
1684 	if (dnode == link_own_addr(l)) {
1685 		tipc_link_bc_ack_rcv(l, acked, xmitq);
1686 		rc = tipc_link_retrans(l->bc_sndlink, from, to, xmitq);
1687 		l->stats.recv_nacks++;
1688 		return rc;
1689 	}
1690 
1691 	/* Msg for other node => suppress own NACK at next sync if applicable */
1692 	if (more(peers_snd_nxt, l->rcv_nxt) && !less(l->rcv_nxt, from))
1693 		l->nack_state = BC_NACK_SND_SUPPRESS;
1694 
1695 	return 0;
1696 }
1697 
1698 void tipc_link_set_queue_limits(struct tipc_link *l, u32 win)
1699 {
1700 	int max_bulk = TIPC_MAX_PUBLICATIONS / (l->mtu / ITEM_SIZE);
1701 
1702 	l->window = win;
1703 	l->backlog[TIPC_LOW_IMPORTANCE].limit      = win / 2;
1704 	l->backlog[TIPC_MEDIUM_IMPORTANCE].limit   = win;
1705 	l->backlog[TIPC_HIGH_IMPORTANCE].limit     = win / 2 * 3;
1706 	l->backlog[TIPC_CRITICAL_IMPORTANCE].limit = win * 2;
1707 	l->backlog[TIPC_SYSTEM_IMPORTANCE].limit   = max_bulk;
1708 }
1709 
1710 /**
1711  * link_reset_stats - reset link statistics
1712  * @l: pointer to link
1713  */
1714 void tipc_link_reset_stats(struct tipc_link *l)
1715 {
1716 	memset(&l->stats, 0, sizeof(l->stats));
1717 	if (!link_is_bc_sndlink(l)) {
1718 		l->stats.sent_info = l->snd_nxt;
1719 		l->stats.recv_info = l->rcv_nxt;
1720 	}
1721 }
1722 
1723 static void link_print(struct tipc_link *l, const char *str)
1724 {
1725 	struct sk_buff *hskb = skb_peek(&l->transmq);
1726 	u16 head = hskb ? msg_seqno(buf_msg(hskb)) : l->snd_nxt - 1;
1727 	u16 tail = l->snd_nxt - 1;
1728 
1729 	pr_info("%s Link <%s> state %x\n", str, l->name, l->state);
1730 	pr_info("XMTQ: %u [%u-%u], BKLGQ: %u, SNDNX: %u, RCVNX: %u\n",
1731 		skb_queue_len(&l->transmq), head, tail,
1732 		skb_queue_len(&l->backlogq), l->snd_nxt, l->rcv_nxt);
1733 }
1734 
1735 /* Parse and validate nested (link) properties valid for media, bearer and link
1736  */
1737 int tipc_nl_parse_link_prop(struct nlattr *prop, struct nlattr *props[])
1738 {
1739 	int err;
1740 
1741 	err = nla_parse_nested(props, TIPC_NLA_PROP_MAX, prop,
1742 			       tipc_nl_prop_policy);
1743 	if (err)
1744 		return err;
1745 
1746 	if (props[TIPC_NLA_PROP_PRIO]) {
1747 		u32 prio;
1748 
1749 		prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
1750 		if (prio > TIPC_MAX_LINK_PRI)
1751 			return -EINVAL;
1752 	}
1753 
1754 	if (props[TIPC_NLA_PROP_TOL]) {
1755 		u32 tol;
1756 
1757 		tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
1758 		if ((tol < TIPC_MIN_LINK_TOL) || (tol > TIPC_MAX_LINK_TOL))
1759 			return -EINVAL;
1760 	}
1761 
1762 	if (props[TIPC_NLA_PROP_WIN]) {
1763 		u32 win;
1764 
1765 		win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
1766 		if ((win < TIPC_MIN_LINK_WIN) || (win > TIPC_MAX_LINK_WIN))
1767 			return -EINVAL;
1768 	}
1769 
1770 	return 0;
1771 }
1772 
1773 static int __tipc_nl_add_stats(struct sk_buff *skb, struct tipc_stats *s)
1774 {
1775 	int i;
1776 	struct nlattr *stats;
1777 
1778 	struct nla_map {
1779 		u32 key;
1780 		u32 val;
1781 	};
1782 
1783 	struct nla_map map[] = {
1784 		{TIPC_NLA_STATS_RX_INFO, s->recv_info},
1785 		{TIPC_NLA_STATS_RX_FRAGMENTS, s->recv_fragments},
1786 		{TIPC_NLA_STATS_RX_FRAGMENTED, s->recv_fragmented},
1787 		{TIPC_NLA_STATS_RX_BUNDLES, s->recv_bundles},
1788 		{TIPC_NLA_STATS_RX_BUNDLED, s->recv_bundled},
1789 		{TIPC_NLA_STATS_TX_INFO, s->sent_info},
1790 		{TIPC_NLA_STATS_TX_FRAGMENTS, s->sent_fragments},
1791 		{TIPC_NLA_STATS_TX_FRAGMENTED, s->sent_fragmented},
1792 		{TIPC_NLA_STATS_TX_BUNDLES, s->sent_bundles},
1793 		{TIPC_NLA_STATS_TX_BUNDLED, s->sent_bundled},
1794 		{TIPC_NLA_STATS_MSG_PROF_TOT, (s->msg_length_counts) ?
1795 			s->msg_length_counts : 1},
1796 		{TIPC_NLA_STATS_MSG_LEN_CNT, s->msg_length_counts},
1797 		{TIPC_NLA_STATS_MSG_LEN_TOT, s->msg_lengths_total},
1798 		{TIPC_NLA_STATS_MSG_LEN_P0, s->msg_length_profile[0]},
1799 		{TIPC_NLA_STATS_MSG_LEN_P1, s->msg_length_profile[1]},
1800 		{TIPC_NLA_STATS_MSG_LEN_P2, s->msg_length_profile[2]},
1801 		{TIPC_NLA_STATS_MSG_LEN_P3, s->msg_length_profile[3]},
1802 		{TIPC_NLA_STATS_MSG_LEN_P4, s->msg_length_profile[4]},
1803 		{TIPC_NLA_STATS_MSG_LEN_P5, s->msg_length_profile[5]},
1804 		{TIPC_NLA_STATS_MSG_LEN_P6, s->msg_length_profile[6]},
1805 		{TIPC_NLA_STATS_RX_STATES, s->recv_states},
1806 		{TIPC_NLA_STATS_RX_PROBES, s->recv_probes},
1807 		{TIPC_NLA_STATS_RX_NACKS, s->recv_nacks},
1808 		{TIPC_NLA_STATS_RX_DEFERRED, s->deferred_recv},
1809 		{TIPC_NLA_STATS_TX_STATES, s->sent_states},
1810 		{TIPC_NLA_STATS_TX_PROBES, s->sent_probes},
1811 		{TIPC_NLA_STATS_TX_NACKS, s->sent_nacks},
1812 		{TIPC_NLA_STATS_TX_ACKS, s->sent_acks},
1813 		{TIPC_NLA_STATS_RETRANSMITTED, s->retransmitted},
1814 		{TIPC_NLA_STATS_DUPLICATES, s->duplicates},
1815 		{TIPC_NLA_STATS_LINK_CONGS, s->link_congs},
1816 		{TIPC_NLA_STATS_MAX_QUEUE, s->max_queue_sz},
1817 		{TIPC_NLA_STATS_AVG_QUEUE, s->queue_sz_counts ?
1818 			(s->accu_queue_sz / s->queue_sz_counts) : 0}
1819 	};
1820 
1821 	stats = nla_nest_start(skb, TIPC_NLA_LINK_STATS);
1822 	if (!stats)
1823 		return -EMSGSIZE;
1824 
1825 	for (i = 0; i <  ARRAY_SIZE(map); i++)
1826 		if (nla_put_u32(skb, map[i].key, map[i].val))
1827 			goto msg_full;
1828 
1829 	nla_nest_end(skb, stats);
1830 
1831 	return 0;
1832 msg_full:
1833 	nla_nest_cancel(skb, stats);
1834 
1835 	return -EMSGSIZE;
1836 }
1837 
1838 /* Caller should hold appropriate locks to protect the link */
1839 int __tipc_nl_add_link(struct net *net, struct tipc_nl_msg *msg,
1840 		       struct tipc_link *link, int nlflags)
1841 {
1842 	int err;
1843 	void *hdr;
1844 	struct nlattr *attrs;
1845 	struct nlattr *prop;
1846 	struct tipc_net *tn = net_generic(net, tipc_net_id);
1847 
1848 	hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
1849 			  nlflags, TIPC_NL_LINK_GET);
1850 	if (!hdr)
1851 		return -EMSGSIZE;
1852 
1853 	attrs = nla_nest_start(msg->skb, TIPC_NLA_LINK);
1854 	if (!attrs)
1855 		goto msg_full;
1856 
1857 	if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, link->name))
1858 		goto attr_msg_full;
1859 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_DEST,
1860 			tipc_cluster_mask(tn->own_addr)))
1861 		goto attr_msg_full;
1862 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_MTU, link->mtu))
1863 		goto attr_msg_full;
1864 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, link->rcv_nxt))
1865 		goto attr_msg_full;
1866 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, link->snd_nxt))
1867 		goto attr_msg_full;
1868 
1869 	if (tipc_link_is_up(link))
1870 		if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
1871 			goto attr_msg_full;
1872 	if (link->active)
1873 		if (nla_put_flag(msg->skb, TIPC_NLA_LINK_ACTIVE))
1874 			goto attr_msg_full;
1875 
1876 	prop = nla_nest_start(msg->skb, TIPC_NLA_LINK_PROP);
1877 	if (!prop)
1878 		goto attr_msg_full;
1879 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
1880 		goto prop_msg_full;
1881 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_TOL, link->tolerance))
1882 		goto prop_msg_full;
1883 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN,
1884 			link->window))
1885 		goto prop_msg_full;
1886 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
1887 		goto prop_msg_full;
1888 	nla_nest_end(msg->skb, prop);
1889 
1890 	err = __tipc_nl_add_stats(msg->skb, &link->stats);
1891 	if (err)
1892 		goto attr_msg_full;
1893 
1894 	nla_nest_end(msg->skb, attrs);
1895 	genlmsg_end(msg->skb, hdr);
1896 
1897 	return 0;
1898 
1899 prop_msg_full:
1900 	nla_nest_cancel(msg->skb, prop);
1901 attr_msg_full:
1902 	nla_nest_cancel(msg->skb, attrs);
1903 msg_full:
1904 	genlmsg_cancel(msg->skb, hdr);
1905 
1906 	return -EMSGSIZE;
1907 }
1908 
1909 static int __tipc_nl_add_bc_link_stat(struct sk_buff *skb,
1910 				      struct tipc_stats *stats)
1911 {
1912 	int i;
1913 	struct nlattr *nest;
1914 
1915 	struct nla_map {
1916 		__u32 key;
1917 		__u32 val;
1918 	};
1919 
1920 	struct nla_map map[] = {
1921 		{TIPC_NLA_STATS_RX_INFO, stats->recv_info},
1922 		{TIPC_NLA_STATS_RX_FRAGMENTS, stats->recv_fragments},
1923 		{TIPC_NLA_STATS_RX_FRAGMENTED, stats->recv_fragmented},
1924 		{TIPC_NLA_STATS_RX_BUNDLES, stats->recv_bundles},
1925 		{TIPC_NLA_STATS_RX_BUNDLED, stats->recv_bundled},
1926 		{TIPC_NLA_STATS_TX_INFO, stats->sent_info},
1927 		{TIPC_NLA_STATS_TX_FRAGMENTS, stats->sent_fragments},
1928 		{TIPC_NLA_STATS_TX_FRAGMENTED, stats->sent_fragmented},
1929 		{TIPC_NLA_STATS_TX_BUNDLES, stats->sent_bundles},
1930 		{TIPC_NLA_STATS_TX_BUNDLED, stats->sent_bundled},
1931 		{TIPC_NLA_STATS_RX_NACKS, stats->recv_nacks},
1932 		{TIPC_NLA_STATS_RX_DEFERRED, stats->deferred_recv},
1933 		{TIPC_NLA_STATS_TX_NACKS, stats->sent_nacks},
1934 		{TIPC_NLA_STATS_TX_ACKS, stats->sent_acks},
1935 		{TIPC_NLA_STATS_RETRANSMITTED, stats->retransmitted},
1936 		{TIPC_NLA_STATS_DUPLICATES, stats->duplicates},
1937 		{TIPC_NLA_STATS_LINK_CONGS, stats->link_congs},
1938 		{TIPC_NLA_STATS_MAX_QUEUE, stats->max_queue_sz},
1939 		{TIPC_NLA_STATS_AVG_QUEUE, stats->queue_sz_counts ?
1940 			(stats->accu_queue_sz / stats->queue_sz_counts) : 0}
1941 	};
1942 
1943 	nest = nla_nest_start(skb, TIPC_NLA_LINK_STATS);
1944 	if (!nest)
1945 		return -EMSGSIZE;
1946 
1947 	for (i = 0; i <  ARRAY_SIZE(map); i++)
1948 		if (nla_put_u32(skb, map[i].key, map[i].val))
1949 			goto msg_full;
1950 
1951 	nla_nest_end(skb, nest);
1952 
1953 	return 0;
1954 msg_full:
1955 	nla_nest_cancel(skb, nest);
1956 
1957 	return -EMSGSIZE;
1958 }
1959 
1960 int tipc_nl_add_bc_link(struct net *net, struct tipc_nl_msg *msg)
1961 {
1962 	int err;
1963 	void *hdr;
1964 	struct nlattr *attrs;
1965 	struct nlattr *prop;
1966 	struct tipc_net *tn = net_generic(net, tipc_net_id);
1967 	struct tipc_link *bcl = tn->bcl;
1968 
1969 	if (!bcl)
1970 		return 0;
1971 
1972 	tipc_bcast_lock(net);
1973 
1974 	hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
1975 			  NLM_F_MULTI, TIPC_NL_LINK_GET);
1976 	if (!hdr) {
1977 		tipc_bcast_unlock(net);
1978 		return -EMSGSIZE;
1979 	}
1980 
1981 	attrs = nla_nest_start(msg->skb, TIPC_NLA_LINK);
1982 	if (!attrs)
1983 		goto msg_full;
1984 
1985 	/* The broadcast link is always up */
1986 	if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
1987 		goto attr_msg_full;
1988 
1989 	if (nla_put_flag(msg->skb, TIPC_NLA_LINK_BROADCAST))
1990 		goto attr_msg_full;
1991 	if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, bcl->name))
1992 		goto attr_msg_full;
1993 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, bcl->rcv_nxt))
1994 		goto attr_msg_full;
1995 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, bcl->snd_nxt))
1996 		goto attr_msg_full;
1997 
1998 	prop = nla_nest_start(msg->skb, TIPC_NLA_LINK_PROP);
1999 	if (!prop)
2000 		goto attr_msg_full;
2001 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN, bcl->window))
2002 		goto prop_msg_full;
2003 	nla_nest_end(msg->skb, prop);
2004 
2005 	err = __tipc_nl_add_bc_link_stat(msg->skb, &bcl->stats);
2006 	if (err)
2007 		goto attr_msg_full;
2008 
2009 	tipc_bcast_unlock(net);
2010 	nla_nest_end(msg->skb, attrs);
2011 	genlmsg_end(msg->skb, hdr);
2012 
2013 	return 0;
2014 
2015 prop_msg_full:
2016 	nla_nest_cancel(msg->skb, prop);
2017 attr_msg_full:
2018 	nla_nest_cancel(msg->skb, attrs);
2019 msg_full:
2020 	tipc_bcast_unlock(net);
2021 	genlmsg_cancel(msg->skb, hdr);
2022 
2023 	return -EMSGSIZE;
2024 }
2025 
2026 void tipc_link_set_tolerance(struct tipc_link *l, u32 tol)
2027 {
2028 	l->tolerance = tol;
2029 	tipc_link_proto_xmit(l, STATE_MSG, 0, 0, tol, 0);
2030 }
2031 
2032 void tipc_link_set_prio(struct tipc_link *l, u32 prio)
2033 {
2034 	l->priority = prio;
2035 	tipc_link_proto_xmit(l, STATE_MSG, 0, 0, 0, prio);
2036 }
2037 
2038 void tipc_link_set_abort_limit(struct tipc_link *l, u32 limit)
2039 {
2040 	l->abort_limit = limit;
2041 }
2042