xref: /linux/net/tipc/link.c (revision 3213486f2e442831e324cc6201a2f9e924ecc235)
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 #include "monitor.h"
46 #include "trace.h"
47 
48 #include <linux/pkt_sched.h>
49 
50 struct tipc_stats {
51 	u32 sent_pkts;
52 	u32 recv_pkts;
53 	u32 sent_states;
54 	u32 recv_states;
55 	u32 sent_probes;
56 	u32 recv_probes;
57 	u32 sent_nacks;
58 	u32 recv_nacks;
59 	u32 sent_acks;
60 	u32 sent_bundled;
61 	u32 sent_bundles;
62 	u32 recv_bundled;
63 	u32 recv_bundles;
64 	u32 retransmitted;
65 	u32 sent_fragmented;
66 	u32 sent_fragments;
67 	u32 recv_fragmented;
68 	u32 recv_fragments;
69 	u32 link_congs;		/* # port sends blocked by congestion */
70 	u32 deferred_recv;
71 	u32 duplicates;
72 	u32 max_queue_sz;	/* send queue size high water mark */
73 	u32 accu_queue_sz;	/* used for send queue size profiling */
74 	u32 queue_sz_counts;	/* used for send queue size profiling */
75 	u32 msg_length_counts;	/* used for message length profiling */
76 	u32 msg_lengths_total;	/* used for message length profiling */
77 	u32 msg_length_profile[7]; /* used for msg. length profiling */
78 };
79 
80 /**
81  * struct tipc_link - TIPC link data structure
82  * @addr: network address of link's peer node
83  * @name: link name character string
84  * @media_addr: media address to use when sending messages over link
85  * @timer: link timer
86  * @net: pointer to namespace struct
87  * @refcnt: reference counter for permanent references (owner node & timer)
88  * @peer_session: link session # being used by peer end of link
89  * @peer_bearer_id: bearer id used by link's peer endpoint
90  * @bearer_id: local bearer id used by link
91  * @tolerance: minimum link continuity loss needed to reset link [in ms]
92  * @abort_limit: # of unacknowledged continuity probes needed to reset link
93  * @state: current state of link FSM
94  * @peer_caps: bitmap describing capabilities of peer node
95  * @silent_intv_cnt: # of timer intervals without any reception from peer
96  * @proto_msg: template for control messages generated by link
97  * @pmsg: convenience pointer to "proto_msg" field
98  * @priority: current link priority
99  * @net_plane: current link network plane ('A' through 'H')
100  * @mon_state: cookie with information needed by link monitor
101  * @backlog_limit: backlog queue congestion thresholds (indexed by importance)
102  * @exp_msg_count: # of tunnelled messages expected during link changeover
103  * @reset_rcv_checkpt: seq # of last acknowledged message at time of link reset
104  * @mtu: current maximum packet size for this link
105  * @advertised_mtu: advertised own mtu when link is being established
106  * @transmitq: queue for sent, non-acked messages
107  * @backlogq: queue for messages waiting to be sent
108  * @snt_nxt: next sequence number to use for outbound messages
109  * @prev_from: sequence number of most previous retransmission request
110  * @stale_cnt: counter for number of identical retransmit attempts
111  * @stale_limit: time when repeated identical retransmits must force link reset
112  * @ackers: # of peers that needs to ack each packet before it can be released
113  * @acked: # last packet acked by a certain peer. Used for broadcast.
114  * @rcv_nxt: next sequence number to expect for inbound messages
115  * @deferred_queue: deferred queue saved OOS b'cast message received from node
116  * @unacked_window: # of inbound messages rx'd without ack'ing back to peer
117  * @inputq: buffer queue for messages to be delivered upwards
118  * @namedq: buffer queue for name table messages to be delivered upwards
119  * @next_out: ptr to first unsent outbound message in queue
120  * @wakeupq: linked list of wakeup msgs waiting for link congestion to abate
121  * @long_msg_seq_no: next identifier to use for outbound fragmented messages
122  * @reasm_buf: head of partially reassembled inbound message fragments
123  * @bc_rcvr: marks that this is a broadcast receiver link
124  * @stats: collects statistics regarding link activity
125  */
126 struct tipc_link {
127 	u32 addr;
128 	char name[TIPC_MAX_LINK_NAME];
129 	struct net *net;
130 
131 	/* Management and link supervision data */
132 	u16 peer_session;
133 	u16 session;
134 	u16 snd_nxt_state;
135 	u16 rcv_nxt_state;
136 	u32 peer_bearer_id;
137 	u32 bearer_id;
138 	u32 tolerance;
139 	u32 abort_limit;
140 	u32 state;
141 	u16 peer_caps;
142 	bool in_session;
143 	bool active;
144 	u32 silent_intv_cnt;
145 	char if_name[TIPC_MAX_IF_NAME];
146 	u32 priority;
147 	char net_plane;
148 	struct tipc_mon_state mon_state;
149 	u16 rst_cnt;
150 
151 	/* Failover/synch */
152 	u16 drop_point;
153 	struct sk_buff *failover_reasm_skb;
154 
155 	/* Max packet negotiation */
156 	u16 mtu;
157 	u16 advertised_mtu;
158 
159 	/* Sending */
160 	struct sk_buff_head transmq;
161 	struct sk_buff_head backlogq;
162 	struct {
163 		u16 len;
164 		u16 limit;
165 	} backlog[5];
166 	u16 snd_nxt;
167 	u16 prev_from;
168 	u16 window;
169 	u16 stale_cnt;
170 	unsigned long stale_limit;
171 
172 	/* Reception */
173 	u16 rcv_nxt;
174 	u32 rcv_unacked;
175 	struct sk_buff_head deferdq;
176 	struct sk_buff_head *inputq;
177 	struct sk_buff_head *namedq;
178 
179 	/* Congestion handling */
180 	struct sk_buff_head wakeupq;
181 
182 	/* Fragmentation/reassembly */
183 	struct sk_buff *reasm_buf;
184 
185 	/* Broadcast */
186 	u16 ackers;
187 	u16 acked;
188 	struct tipc_link *bc_rcvlink;
189 	struct tipc_link *bc_sndlink;
190 	u8 nack_state;
191 	bool bc_peer_is_up;
192 
193 	/* Statistics */
194 	struct tipc_stats stats;
195 };
196 
197 /*
198  * Error message prefixes
199  */
200 static const char *link_co_err = "Link tunneling error, ";
201 static const char *link_rst_msg = "Resetting link ";
202 
203 /* Send states for broadcast NACKs
204  */
205 enum {
206 	BC_NACK_SND_CONDITIONAL,
207 	BC_NACK_SND_UNCONDITIONAL,
208 	BC_NACK_SND_SUPPRESS,
209 };
210 
211 #define TIPC_BC_RETR_LIM msecs_to_jiffies(10)   /* [ms] */
212 
213 /*
214  * Interval between NACKs when packets arrive out of order
215  */
216 #define TIPC_NACK_INTV (TIPC_MIN_LINK_WIN * 2)
217 
218 /* Link FSM states:
219  */
220 enum {
221 	LINK_ESTABLISHED     = 0xe,
222 	LINK_ESTABLISHING    = 0xe  << 4,
223 	LINK_RESET           = 0x1  << 8,
224 	LINK_RESETTING       = 0x2  << 12,
225 	LINK_PEER_RESET      = 0xd  << 16,
226 	LINK_FAILINGOVER     = 0xf  << 20,
227 	LINK_SYNCHING        = 0xc  << 24
228 };
229 
230 /* Link FSM state checking routines
231  */
232 static int link_is_up(struct tipc_link *l)
233 {
234 	return l->state & (LINK_ESTABLISHED | LINK_SYNCHING);
235 }
236 
237 static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
238 			       struct sk_buff_head *xmitq);
239 static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
240 				      bool probe_reply, u16 rcvgap,
241 				      int tolerance, int priority,
242 				      struct sk_buff_head *xmitq);
243 static void link_print(struct tipc_link *l, const char *str);
244 static int tipc_link_build_nack_msg(struct tipc_link *l,
245 				    struct sk_buff_head *xmitq);
246 static void tipc_link_build_bc_init_msg(struct tipc_link *l,
247 					struct sk_buff_head *xmitq);
248 static bool tipc_link_release_pkts(struct tipc_link *l, u16 to);
249 
250 /*
251  *  Simple non-static link routines (i.e. referenced outside this file)
252  */
253 bool tipc_link_is_up(struct tipc_link *l)
254 {
255 	return link_is_up(l);
256 }
257 
258 bool tipc_link_peer_is_down(struct tipc_link *l)
259 {
260 	return l->state == LINK_PEER_RESET;
261 }
262 
263 bool tipc_link_is_reset(struct tipc_link *l)
264 {
265 	return l->state & (LINK_RESET | LINK_FAILINGOVER | LINK_ESTABLISHING);
266 }
267 
268 bool tipc_link_is_establishing(struct tipc_link *l)
269 {
270 	return l->state == LINK_ESTABLISHING;
271 }
272 
273 bool tipc_link_is_synching(struct tipc_link *l)
274 {
275 	return l->state == LINK_SYNCHING;
276 }
277 
278 bool tipc_link_is_failingover(struct tipc_link *l)
279 {
280 	return l->state == LINK_FAILINGOVER;
281 }
282 
283 bool tipc_link_is_blocked(struct tipc_link *l)
284 {
285 	return l->state & (LINK_RESETTING | LINK_PEER_RESET | LINK_FAILINGOVER);
286 }
287 
288 static bool link_is_bc_sndlink(struct tipc_link *l)
289 {
290 	return !l->bc_sndlink;
291 }
292 
293 static bool link_is_bc_rcvlink(struct tipc_link *l)
294 {
295 	return ((l->bc_rcvlink == l) && !link_is_bc_sndlink(l));
296 }
297 
298 void tipc_link_set_active(struct tipc_link *l, bool active)
299 {
300 	l->active = active;
301 }
302 
303 u32 tipc_link_id(struct tipc_link *l)
304 {
305 	return l->peer_bearer_id << 16 | l->bearer_id;
306 }
307 
308 int tipc_link_window(struct tipc_link *l)
309 {
310 	return l->window;
311 }
312 
313 int tipc_link_prio(struct tipc_link *l)
314 {
315 	return l->priority;
316 }
317 
318 unsigned long tipc_link_tolerance(struct tipc_link *l)
319 {
320 	return l->tolerance;
321 }
322 
323 struct sk_buff_head *tipc_link_inputq(struct tipc_link *l)
324 {
325 	return l->inputq;
326 }
327 
328 char tipc_link_plane(struct tipc_link *l)
329 {
330 	return l->net_plane;
331 }
332 
333 void tipc_link_update_caps(struct tipc_link *l, u16 capabilities)
334 {
335 	l->peer_caps = capabilities;
336 }
337 
338 void tipc_link_add_bc_peer(struct tipc_link *snd_l,
339 			   struct tipc_link *uc_l,
340 			   struct sk_buff_head *xmitq)
341 {
342 	struct tipc_link *rcv_l = uc_l->bc_rcvlink;
343 
344 	snd_l->ackers++;
345 	rcv_l->acked = snd_l->snd_nxt - 1;
346 	snd_l->state = LINK_ESTABLISHED;
347 	tipc_link_build_bc_init_msg(uc_l, xmitq);
348 }
349 
350 void tipc_link_remove_bc_peer(struct tipc_link *snd_l,
351 			      struct tipc_link *rcv_l,
352 			      struct sk_buff_head *xmitq)
353 {
354 	u16 ack = snd_l->snd_nxt - 1;
355 
356 	snd_l->ackers--;
357 	rcv_l->bc_peer_is_up = true;
358 	rcv_l->state = LINK_ESTABLISHED;
359 	tipc_link_bc_ack_rcv(rcv_l, ack, xmitq);
360 	trace_tipc_link_reset(rcv_l, TIPC_DUMP_ALL, "bclink removed!");
361 	tipc_link_reset(rcv_l);
362 	rcv_l->state = LINK_RESET;
363 	if (!snd_l->ackers) {
364 		trace_tipc_link_reset(snd_l, TIPC_DUMP_ALL, "zero ackers!");
365 		tipc_link_reset(snd_l);
366 		snd_l->state = LINK_RESET;
367 		__skb_queue_purge(xmitq);
368 	}
369 }
370 
371 int tipc_link_bc_peers(struct tipc_link *l)
372 {
373 	return l->ackers;
374 }
375 
376 static u16 link_bc_rcv_gap(struct tipc_link *l)
377 {
378 	struct sk_buff *skb = skb_peek(&l->deferdq);
379 	u16 gap = 0;
380 
381 	if (more(l->snd_nxt, l->rcv_nxt))
382 		gap = l->snd_nxt - l->rcv_nxt;
383 	if (skb)
384 		gap = buf_seqno(skb) - l->rcv_nxt;
385 	return gap;
386 }
387 
388 void tipc_link_set_mtu(struct tipc_link *l, int mtu)
389 {
390 	l->mtu = mtu;
391 }
392 
393 int tipc_link_mtu(struct tipc_link *l)
394 {
395 	return l->mtu;
396 }
397 
398 u16 tipc_link_rcv_nxt(struct tipc_link *l)
399 {
400 	return l->rcv_nxt;
401 }
402 
403 u16 tipc_link_acked(struct tipc_link *l)
404 {
405 	return l->acked;
406 }
407 
408 char *tipc_link_name(struct tipc_link *l)
409 {
410 	return l->name;
411 }
412 
413 u32 tipc_link_state(struct tipc_link *l)
414 {
415 	return l->state;
416 }
417 
418 /**
419  * tipc_link_create - create a new link
420  * @n: pointer to associated node
421  * @if_name: associated interface name
422  * @bearer_id: id (index) of associated bearer
423  * @tolerance: link tolerance to be used by link
424  * @net_plane: network plane (A,B,c..) this link belongs to
425  * @mtu: mtu to be advertised by link
426  * @priority: priority to be used by link
427  * @window: send window to be used by link
428  * @session: session to be used by link
429  * @ownnode: identity of own node
430  * @peer: node id of peer node
431  * @peer_caps: bitmap describing peer node capabilities
432  * @bc_sndlink: the namespace global link used for broadcast sending
433  * @bc_rcvlink: the peer specific link used for broadcast reception
434  * @inputq: queue to put messages ready for delivery
435  * @namedq: queue to put binding table update messages ready for delivery
436  * @link: return value, pointer to put the created link
437  *
438  * Returns true if link was created, otherwise false
439  */
440 bool tipc_link_create(struct net *net, char *if_name, int bearer_id,
441 		      int tolerance, char net_plane, u32 mtu, int priority,
442 		      int window, u32 session, u32 self,
443 		      u32 peer, u8 *peer_id, u16 peer_caps,
444 		      struct tipc_link *bc_sndlink,
445 		      struct tipc_link *bc_rcvlink,
446 		      struct sk_buff_head *inputq,
447 		      struct sk_buff_head *namedq,
448 		      struct tipc_link **link)
449 {
450 	char peer_str[NODE_ID_STR_LEN] = {0,};
451 	char self_str[NODE_ID_STR_LEN] = {0,};
452 	struct tipc_link *l;
453 
454 	l = kzalloc(sizeof(*l), GFP_ATOMIC);
455 	if (!l)
456 		return false;
457 	*link = l;
458 	l->session = session;
459 
460 	/* Set link name for unicast links only */
461 	if (peer_id) {
462 		tipc_nodeid2string(self_str, tipc_own_id(net));
463 		if (strlen(self_str) > 16)
464 			sprintf(self_str, "%x", self);
465 		tipc_nodeid2string(peer_str, peer_id);
466 		if (strlen(peer_str) > 16)
467 			sprintf(peer_str, "%x", peer);
468 	}
469 	/* Peer i/f name will be completed by reset/activate message */
470 	snprintf(l->name, sizeof(l->name), "%s:%s-%s:unknown",
471 		 self_str, if_name, peer_str);
472 
473 	strcpy(l->if_name, if_name);
474 	l->addr = peer;
475 	l->peer_caps = peer_caps;
476 	l->net = net;
477 	l->in_session = false;
478 	l->bearer_id = bearer_id;
479 	l->tolerance = tolerance;
480 	if (bc_rcvlink)
481 		bc_rcvlink->tolerance = tolerance;
482 	l->net_plane = net_plane;
483 	l->advertised_mtu = mtu;
484 	l->mtu = mtu;
485 	l->priority = priority;
486 	tipc_link_set_queue_limits(l, window);
487 	l->ackers = 1;
488 	l->bc_sndlink = bc_sndlink;
489 	l->bc_rcvlink = bc_rcvlink;
490 	l->inputq = inputq;
491 	l->namedq = namedq;
492 	l->state = LINK_RESETTING;
493 	__skb_queue_head_init(&l->transmq);
494 	__skb_queue_head_init(&l->backlogq);
495 	__skb_queue_head_init(&l->deferdq);
496 	skb_queue_head_init(&l->wakeupq);
497 	skb_queue_head_init(l->inputq);
498 	return true;
499 }
500 
501 /**
502  * tipc_link_bc_create - create new link to be used for broadcast
503  * @n: pointer to associated node
504  * @mtu: mtu to be used initially if no peers
505  * @window: send window to be used
506  * @inputq: queue to put messages ready for delivery
507  * @namedq: queue to put binding table update messages ready for delivery
508  * @link: return value, pointer to put the created link
509  *
510  * Returns true if link was created, otherwise false
511  */
512 bool tipc_link_bc_create(struct net *net, u32 ownnode, u32 peer,
513 			 int mtu, int window, u16 peer_caps,
514 			 struct sk_buff_head *inputq,
515 			 struct sk_buff_head *namedq,
516 			 struct tipc_link *bc_sndlink,
517 			 struct tipc_link **link)
518 {
519 	struct tipc_link *l;
520 
521 	if (!tipc_link_create(net, "", MAX_BEARERS, 0, 'Z', mtu, 0, window,
522 			      0, ownnode, peer, NULL, peer_caps, bc_sndlink,
523 			      NULL, inputq, namedq, link))
524 		return false;
525 
526 	l = *link;
527 	strcpy(l->name, tipc_bclink_name);
528 	trace_tipc_link_reset(l, TIPC_DUMP_ALL, "bclink created!");
529 	tipc_link_reset(l);
530 	l->state = LINK_RESET;
531 	l->ackers = 0;
532 	l->bc_rcvlink = l;
533 
534 	/* Broadcast send link is always up */
535 	if (link_is_bc_sndlink(l))
536 		l->state = LINK_ESTABLISHED;
537 
538 	/* Disable replicast if even a single peer doesn't support it */
539 	if (link_is_bc_rcvlink(l) && !(peer_caps & TIPC_BCAST_RCAST))
540 		tipc_bcast_disable_rcast(net);
541 
542 	return true;
543 }
544 
545 /**
546  * tipc_link_fsm_evt - link finite state machine
547  * @l: pointer to link
548  * @evt: state machine event to be processed
549  */
550 int tipc_link_fsm_evt(struct tipc_link *l, int evt)
551 {
552 	int rc = 0;
553 	int old_state = l->state;
554 
555 	switch (l->state) {
556 	case LINK_RESETTING:
557 		switch (evt) {
558 		case LINK_PEER_RESET_EVT:
559 			l->state = LINK_PEER_RESET;
560 			break;
561 		case LINK_RESET_EVT:
562 			l->state = LINK_RESET;
563 			break;
564 		case LINK_FAILURE_EVT:
565 		case LINK_FAILOVER_BEGIN_EVT:
566 		case LINK_ESTABLISH_EVT:
567 		case LINK_FAILOVER_END_EVT:
568 		case LINK_SYNCH_BEGIN_EVT:
569 		case LINK_SYNCH_END_EVT:
570 		default:
571 			goto illegal_evt;
572 		}
573 		break;
574 	case LINK_RESET:
575 		switch (evt) {
576 		case LINK_PEER_RESET_EVT:
577 			l->state = LINK_ESTABLISHING;
578 			break;
579 		case LINK_FAILOVER_BEGIN_EVT:
580 			l->state = LINK_FAILINGOVER;
581 		case LINK_FAILURE_EVT:
582 		case LINK_RESET_EVT:
583 		case LINK_ESTABLISH_EVT:
584 		case LINK_FAILOVER_END_EVT:
585 			break;
586 		case LINK_SYNCH_BEGIN_EVT:
587 		case LINK_SYNCH_END_EVT:
588 		default:
589 			goto illegal_evt;
590 		}
591 		break;
592 	case LINK_PEER_RESET:
593 		switch (evt) {
594 		case LINK_RESET_EVT:
595 			l->state = LINK_ESTABLISHING;
596 			break;
597 		case LINK_PEER_RESET_EVT:
598 		case LINK_ESTABLISH_EVT:
599 		case LINK_FAILURE_EVT:
600 			break;
601 		case LINK_SYNCH_BEGIN_EVT:
602 		case LINK_SYNCH_END_EVT:
603 		case LINK_FAILOVER_BEGIN_EVT:
604 		case LINK_FAILOVER_END_EVT:
605 		default:
606 			goto illegal_evt;
607 		}
608 		break;
609 	case LINK_FAILINGOVER:
610 		switch (evt) {
611 		case LINK_FAILOVER_END_EVT:
612 			l->state = LINK_RESET;
613 			break;
614 		case LINK_PEER_RESET_EVT:
615 		case LINK_RESET_EVT:
616 		case LINK_ESTABLISH_EVT:
617 		case LINK_FAILURE_EVT:
618 			break;
619 		case LINK_FAILOVER_BEGIN_EVT:
620 		case LINK_SYNCH_BEGIN_EVT:
621 		case LINK_SYNCH_END_EVT:
622 		default:
623 			goto illegal_evt;
624 		}
625 		break;
626 	case LINK_ESTABLISHING:
627 		switch (evt) {
628 		case LINK_ESTABLISH_EVT:
629 			l->state = LINK_ESTABLISHED;
630 			break;
631 		case LINK_FAILOVER_BEGIN_EVT:
632 			l->state = LINK_FAILINGOVER;
633 			break;
634 		case LINK_RESET_EVT:
635 			l->state = LINK_RESET;
636 			break;
637 		case LINK_FAILURE_EVT:
638 		case LINK_PEER_RESET_EVT:
639 		case LINK_SYNCH_BEGIN_EVT:
640 		case LINK_FAILOVER_END_EVT:
641 			break;
642 		case LINK_SYNCH_END_EVT:
643 		default:
644 			goto illegal_evt;
645 		}
646 		break;
647 	case LINK_ESTABLISHED:
648 		switch (evt) {
649 		case LINK_PEER_RESET_EVT:
650 			l->state = LINK_PEER_RESET;
651 			rc |= TIPC_LINK_DOWN_EVT;
652 			break;
653 		case LINK_FAILURE_EVT:
654 			l->state = LINK_RESETTING;
655 			rc |= TIPC_LINK_DOWN_EVT;
656 			break;
657 		case LINK_RESET_EVT:
658 			l->state = LINK_RESET;
659 			break;
660 		case LINK_ESTABLISH_EVT:
661 		case LINK_SYNCH_END_EVT:
662 			break;
663 		case LINK_SYNCH_BEGIN_EVT:
664 			l->state = LINK_SYNCHING;
665 			break;
666 		case LINK_FAILOVER_BEGIN_EVT:
667 		case LINK_FAILOVER_END_EVT:
668 		default:
669 			goto illegal_evt;
670 		}
671 		break;
672 	case LINK_SYNCHING:
673 		switch (evt) {
674 		case LINK_PEER_RESET_EVT:
675 			l->state = LINK_PEER_RESET;
676 			rc |= TIPC_LINK_DOWN_EVT;
677 			break;
678 		case LINK_FAILURE_EVT:
679 			l->state = LINK_RESETTING;
680 			rc |= TIPC_LINK_DOWN_EVT;
681 			break;
682 		case LINK_RESET_EVT:
683 			l->state = LINK_RESET;
684 			break;
685 		case LINK_ESTABLISH_EVT:
686 		case LINK_SYNCH_BEGIN_EVT:
687 			break;
688 		case LINK_SYNCH_END_EVT:
689 			l->state = LINK_ESTABLISHED;
690 			break;
691 		case LINK_FAILOVER_BEGIN_EVT:
692 		case LINK_FAILOVER_END_EVT:
693 		default:
694 			goto illegal_evt;
695 		}
696 		break;
697 	default:
698 		pr_err("Unknown FSM state %x in %s\n", l->state, l->name);
699 	}
700 	trace_tipc_link_fsm(l->name, old_state, l->state, evt);
701 	return rc;
702 illegal_evt:
703 	pr_err("Illegal FSM event %x in state %x on link %s\n",
704 	       evt, l->state, l->name);
705 	trace_tipc_link_fsm(l->name, old_state, l->state, evt);
706 	return rc;
707 }
708 
709 /* link_profile_stats - update statistical profiling of traffic
710  */
711 static void link_profile_stats(struct tipc_link *l)
712 {
713 	struct sk_buff *skb;
714 	struct tipc_msg *msg;
715 	int length;
716 
717 	/* Update counters used in statistical profiling of send traffic */
718 	l->stats.accu_queue_sz += skb_queue_len(&l->transmq);
719 	l->stats.queue_sz_counts++;
720 
721 	skb = skb_peek(&l->transmq);
722 	if (!skb)
723 		return;
724 	msg = buf_msg(skb);
725 	length = msg_size(msg);
726 
727 	if (msg_user(msg) == MSG_FRAGMENTER) {
728 		if (msg_type(msg) != FIRST_FRAGMENT)
729 			return;
730 		length = msg_size(msg_get_wrapped(msg));
731 	}
732 	l->stats.msg_lengths_total += length;
733 	l->stats.msg_length_counts++;
734 	if (length <= 64)
735 		l->stats.msg_length_profile[0]++;
736 	else if (length <= 256)
737 		l->stats.msg_length_profile[1]++;
738 	else if (length <= 1024)
739 		l->stats.msg_length_profile[2]++;
740 	else if (length <= 4096)
741 		l->stats.msg_length_profile[3]++;
742 	else if (length <= 16384)
743 		l->stats.msg_length_profile[4]++;
744 	else if (length <= 32768)
745 		l->stats.msg_length_profile[5]++;
746 	else
747 		l->stats.msg_length_profile[6]++;
748 }
749 
750 /**
751  * tipc_link_too_silent - check if link is "too silent"
752  * @l: tipc link to be checked
753  *
754  * Returns true if the link 'silent_intv_cnt' is about to reach the
755  * 'abort_limit' value, otherwise false
756  */
757 bool tipc_link_too_silent(struct tipc_link *l)
758 {
759 	return (l->silent_intv_cnt + 2 > l->abort_limit);
760 }
761 
762 /* tipc_link_timeout - perform periodic task as instructed from node timeout
763  */
764 int tipc_link_timeout(struct tipc_link *l, struct sk_buff_head *xmitq)
765 {
766 	int mtyp = 0;
767 	int rc = 0;
768 	bool state = false;
769 	bool probe = false;
770 	bool setup = false;
771 	u16 bc_snt = l->bc_sndlink->snd_nxt - 1;
772 	u16 bc_acked = l->bc_rcvlink->acked;
773 	struct tipc_mon_state *mstate = &l->mon_state;
774 
775 	trace_tipc_link_timeout(l, TIPC_DUMP_NONE, " ");
776 	trace_tipc_link_too_silent(l, TIPC_DUMP_ALL, " ");
777 	switch (l->state) {
778 	case LINK_ESTABLISHED:
779 	case LINK_SYNCHING:
780 		mtyp = STATE_MSG;
781 		link_profile_stats(l);
782 		tipc_mon_get_state(l->net, l->addr, mstate, l->bearer_id);
783 		if (mstate->reset || (l->silent_intv_cnt > l->abort_limit))
784 			return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
785 		state = bc_acked != bc_snt;
786 		state |= l->bc_rcvlink->rcv_unacked;
787 		state |= l->rcv_unacked;
788 		state |= !skb_queue_empty(&l->transmq);
789 		state |= !skb_queue_empty(&l->deferdq);
790 		probe = mstate->probing;
791 		probe |= l->silent_intv_cnt;
792 		if (probe || mstate->monitoring)
793 			l->silent_intv_cnt++;
794 		break;
795 	case LINK_RESET:
796 		setup = l->rst_cnt++ <= 4;
797 		setup |= !(l->rst_cnt % 16);
798 		mtyp = RESET_MSG;
799 		break;
800 	case LINK_ESTABLISHING:
801 		setup = true;
802 		mtyp = ACTIVATE_MSG;
803 		break;
804 	case LINK_PEER_RESET:
805 	case LINK_RESETTING:
806 	case LINK_FAILINGOVER:
807 		break;
808 	default:
809 		break;
810 	}
811 
812 	if (state || probe || setup)
813 		tipc_link_build_proto_msg(l, mtyp, probe, 0, 0, 0, 0, xmitq);
814 
815 	return rc;
816 }
817 
818 /**
819  * link_schedule_user - schedule a message sender for wakeup after congestion
820  * @l: congested link
821  * @hdr: header of message that is being sent
822  * Create pseudo msg to send back to user when congestion abates
823  */
824 static int link_schedule_user(struct tipc_link *l, struct tipc_msg *hdr)
825 {
826 	u32 dnode = tipc_own_addr(l->net);
827 	u32 dport = msg_origport(hdr);
828 	struct sk_buff *skb;
829 
830 	/* Create and schedule wakeup pseudo message */
831 	skb = tipc_msg_create(SOCK_WAKEUP, 0, INT_H_SIZE, 0,
832 			      dnode, l->addr, dport, 0, 0);
833 	if (!skb)
834 		return -ENOBUFS;
835 	msg_set_dest_droppable(buf_msg(skb), true);
836 	TIPC_SKB_CB(skb)->chain_imp = msg_importance(hdr);
837 	skb_queue_tail(&l->wakeupq, skb);
838 	l->stats.link_congs++;
839 	trace_tipc_link_conges(l, TIPC_DUMP_ALL, "wakeup scheduled!");
840 	return -ELINKCONG;
841 }
842 
843 /**
844  * link_prepare_wakeup - prepare users for wakeup after congestion
845  * @l: congested link
846  * Wake up a number of waiting users, as permitted by available space
847  * in the send queue
848  */
849 static void link_prepare_wakeup(struct tipc_link *l)
850 {
851 	struct sk_buff *skb, *tmp;
852 	int imp, i = 0;
853 
854 	skb_queue_walk_safe(&l->wakeupq, skb, tmp) {
855 		imp = TIPC_SKB_CB(skb)->chain_imp;
856 		if (l->backlog[imp].len < l->backlog[imp].limit) {
857 			skb_unlink(skb, &l->wakeupq);
858 			skb_queue_tail(l->inputq, skb);
859 		} else if (i++ > 10) {
860 			break;
861 		}
862 	}
863 }
864 
865 void tipc_link_reset(struct tipc_link *l)
866 {
867 	struct sk_buff_head list;
868 
869 	__skb_queue_head_init(&list);
870 
871 	l->in_session = false;
872 	/* Force re-synch of peer session number before establishing */
873 	l->peer_session--;
874 	l->session++;
875 	l->mtu = l->advertised_mtu;
876 
877 	spin_lock_bh(&l->wakeupq.lock);
878 	skb_queue_splice_init(&l->wakeupq, &list);
879 	spin_unlock_bh(&l->wakeupq.lock);
880 
881 	spin_lock_bh(&l->inputq->lock);
882 	skb_queue_splice_init(&list, l->inputq);
883 	spin_unlock_bh(&l->inputq->lock);
884 
885 	__skb_queue_purge(&l->transmq);
886 	__skb_queue_purge(&l->deferdq);
887 	__skb_queue_purge(&l->backlogq);
888 	l->backlog[TIPC_LOW_IMPORTANCE].len = 0;
889 	l->backlog[TIPC_MEDIUM_IMPORTANCE].len = 0;
890 	l->backlog[TIPC_HIGH_IMPORTANCE].len = 0;
891 	l->backlog[TIPC_CRITICAL_IMPORTANCE].len = 0;
892 	l->backlog[TIPC_SYSTEM_IMPORTANCE].len = 0;
893 	kfree_skb(l->reasm_buf);
894 	kfree_skb(l->failover_reasm_skb);
895 	l->reasm_buf = NULL;
896 	l->failover_reasm_skb = NULL;
897 	l->rcv_unacked = 0;
898 	l->snd_nxt = 1;
899 	l->rcv_nxt = 1;
900 	l->snd_nxt_state = 1;
901 	l->rcv_nxt_state = 1;
902 	l->acked = 0;
903 	l->silent_intv_cnt = 0;
904 	l->rst_cnt = 0;
905 	l->stale_cnt = 0;
906 	l->bc_peer_is_up = false;
907 	memset(&l->mon_state, 0, sizeof(l->mon_state));
908 	tipc_link_reset_stats(l);
909 }
910 
911 /**
912  * tipc_link_xmit(): enqueue buffer list according to queue situation
913  * @link: link to use
914  * @list: chain of buffers containing message
915  * @xmitq: returned list of packets to be sent by caller
916  *
917  * Consumes the buffer chain.
918  * Returns 0 if success, or errno: -ELINKCONG, -EMSGSIZE or -ENOBUFS
919  * Messages at TIPC_SYSTEM_IMPORTANCE are always accepted
920  */
921 int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *list,
922 		   struct sk_buff_head *xmitq)
923 {
924 	struct tipc_msg *hdr = buf_msg(skb_peek(list));
925 	unsigned int maxwin = l->window;
926 	int imp = msg_importance(hdr);
927 	unsigned int mtu = l->mtu;
928 	u16 ack = l->rcv_nxt - 1;
929 	u16 seqno = l->snd_nxt;
930 	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
931 	struct sk_buff_head *transmq = &l->transmq;
932 	struct sk_buff_head *backlogq = &l->backlogq;
933 	struct sk_buff *skb, *_skb, *bskb;
934 	int pkt_cnt = skb_queue_len(list);
935 	int rc = 0;
936 
937 	if (unlikely(msg_size(hdr) > mtu)) {
938 		skb_queue_purge(list);
939 		return -EMSGSIZE;
940 	}
941 
942 	/* Allow oversubscription of one data msg per source at congestion */
943 	if (unlikely(l->backlog[imp].len >= l->backlog[imp].limit)) {
944 		if (imp == TIPC_SYSTEM_IMPORTANCE) {
945 			pr_warn("%s<%s>, link overflow", link_rst_msg, l->name);
946 			return -ENOBUFS;
947 		}
948 		rc = link_schedule_user(l, hdr);
949 	}
950 
951 	if (pkt_cnt > 1) {
952 		l->stats.sent_fragmented++;
953 		l->stats.sent_fragments += pkt_cnt;
954 	}
955 
956 	/* Prepare each packet for sending, and add to relevant queue: */
957 	while (skb_queue_len(list)) {
958 		skb = skb_peek(list);
959 		hdr = buf_msg(skb);
960 		msg_set_seqno(hdr, seqno);
961 		msg_set_ack(hdr, ack);
962 		msg_set_bcast_ack(hdr, bc_ack);
963 
964 		if (likely(skb_queue_len(transmq) < maxwin)) {
965 			_skb = skb_clone(skb, GFP_ATOMIC);
966 			if (!_skb) {
967 				skb_queue_purge(list);
968 				return -ENOBUFS;
969 			}
970 			__skb_dequeue(list);
971 			__skb_queue_tail(transmq, skb);
972 			/* next retransmit attempt */
973 			if (link_is_bc_sndlink(l))
974 				TIPC_SKB_CB(skb)->nxt_retr =
975 					jiffies + TIPC_BC_RETR_LIM;
976 			__skb_queue_tail(xmitq, _skb);
977 			TIPC_SKB_CB(skb)->ackers = l->ackers;
978 			l->rcv_unacked = 0;
979 			l->stats.sent_pkts++;
980 			seqno++;
981 			continue;
982 		}
983 		if (tipc_msg_bundle(skb_peek_tail(backlogq), hdr, mtu)) {
984 			kfree_skb(__skb_dequeue(list));
985 			l->stats.sent_bundled++;
986 			continue;
987 		}
988 		if (tipc_msg_make_bundle(&bskb, hdr, mtu, l->addr)) {
989 			kfree_skb(__skb_dequeue(list));
990 			__skb_queue_tail(backlogq, bskb);
991 			l->backlog[msg_importance(buf_msg(bskb))].len++;
992 			l->stats.sent_bundled++;
993 			l->stats.sent_bundles++;
994 			continue;
995 		}
996 		l->backlog[imp].len += skb_queue_len(list);
997 		skb_queue_splice_tail_init(list, backlogq);
998 	}
999 	l->snd_nxt = seqno;
1000 	return rc;
1001 }
1002 
1003 static void tipc_link_advance_backlog(struct tipc_link *l,
1004 				      struct sk_buff_head *xmitq)
1005 {
1006 	struct sk_buff *skb, *_skb;
1007 	struct tipc_msg *hdr;
1008 	u16 seqno = l->snd_nxt;
1009 	u16 ack = l->rcv_nxt - 1;
1010 	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
1011 
1012 	while (skb_queue_len(&l->transmq) < l->window) {
1013 		skb = skb_peek(&l->backlogq);
1014 		if (!skb)
1015 			break;
1016 		_skb = skb_clone(skb, GFP_ATOMIC);
1017 		if (!_skb)
1018 			break;
1019 		__skb_dequeue(&l->backlogq);
1020 		hdr = buf_msg(skb);
1021 		l->backlog[msg_importance(hdr)].len--;
1022 		__skb_queue_tail(&l->transmq, skb);
1023 		/* next retransmit attempt */
1024 		if (link_is_bc_sndlink(l))
1025 			TIPC_SKB_CB(skb)->nxt_retr = jiffies + TIPC_BC_RETR_LIM;
1026 
1027 		__skb_queue_tail(xmitq, _skb);
1028 		TIPC_SKB_CB(skb)->ackers = l->ackers;
1029 		msg_set_seqno(hdr, seqno);
1030 		msg_set_ack(hdr, ack);
1031 		msg_set_bcast_ack(hdr, bc_ack);
1032 		l->rcv_unacked = 0;
1033 		l->stats.sent_pkts++;
1034 		seqno++;
1035 	}
1036 	l->snd_nxt = seqno;
1037 }
1038 
1039 static void link_retransmit_failure(struct tipc_link *l, struct sk_buff *skb)
1040 {
1041 	struct tipc_msg *hdr = buf_msg(skb);
1042 
1043 	pr_warn("Retransmission failure on link <%s>\n", l->name);
1044 	link_print(l, "State of link ");
1045 	pr_info("Failed msg: usr %u, typ %u, len %u, err %u\n",
1046 		msg_user(hdr), msg_type(hdr), msg_size(hdr), msg_errcode(hdr));
1047 	pr_info("sqno %u, prev: %x, src: %x\n",
1048 		msg_seqno(hdr), msg_prevnode(hdr), msg_orignode(hdr));
1049 }
1050 
1051 /* tipc_link_retrans() - retransmit one or more packets
1052  * @l: the link to transmit on
1053  * @r: the receiving link ordering the retransmit. Same as l if unicast
1054  * @from: retransmit from (inclusive) this sequence number
1055  * @to: retransmit to (inclusive) this sequence number
1056  * xmitq: queue for accumulating the retransmitted packets
1057  */
1058 static int tipc_link_retrans(struct tipc_link *l, struct tipc_link *r,
1059 			     u16 from, u16 to, struct sk_buff_head *xmitq)
1060 {
1061 	struct sk_buff *_skb, *skb = skb_peek(&l->transmq);
1062 	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
1063 	u16 ack = l->rcv_nxt - 1;
1064 	struct tipc_msg *hdr;
1065 
1066 	if (!skb)
1067 		return 0;
1068 	if (less(to, from))
1069 		return 0;
1070 
1071 	trace_tipc_link_retrans(r, from, to, &l->transmq);
1072 	/* Detect repeated retransmit failures on same packet */
1073 	if (r->prev_from != from) {
1074 		r->prev_from = from;
1075 		r->stale_limit = jiffies + msecs_to_jiffies(r->tolerance);
1076 		r->stale_cnt = 0;
1077 	} else if (++r->stale_cnt > 99 && time_after(jiffies, r->stale_limit)) {
1078 		link_retransmit_failure(l, skb);
1079 		trace_tipc_list_dump(&l->transmq, true, "retrans failure!");
1080 		trace_tipc_link_dump(l, TIPC_DUMP_NONE, "retrans failure!");
1081 		trace_tipc_link_dump(r, TIPC_DUMP_NONE, "retrans failure!");
1082 		if (link_is_bc_sndlink(l))
1083 			return TIPC_LINK_DOWN_EVT;
1084 		return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1085 	}
1086 
1087 	skb_queue_walk(&l->transmq, skb) {
1088 		hdr = buf_msg(skb);
1089 		if (less(msg_seqno(hdr), from))
1090 			continue;
1091 		if (more(msg_seqno(hdr), to))
1092 			break;
1093 		if (link_is_bc_sndlink(l)) {
1094 			if (time_before(jiffies, TIPC_SKB_CB(skb)->nxt_retr))
1095 				continue;
1096 			TIPC_SKB_CB(skb)->nxt_retr = jiffies + TIPC_BC_RETR_LIM;
1097 		}
1098 		_skb = __pskb_copy(skb, MIN_H_SIZE, GFP_ATOMIC);
1099 		if (!_skb)
1100 			return 0;
1101 		hdr = buf_msg(_skb);
1102 		msg_set_ack(hdr, ack);
1103 		msg_set_bcast_ack(hdr, bc_ack);
1104 		_skb->priority = TC_PRIO_CONTROL;
1105 		__skb_queue_tail(xmitq, _skb);
1106 		l->stats.retransmitted++;
1107 	}
1108 	return 0;
1109 }
1110 
1111 /* tipc_data_input - deliver data and name distr msgs to upper layer
1112  *
1113  * Consumes buffer if message is of right type
1114  * Node lock must be held
1115  */
1116 static bool tipc_data_input(struct tipc_link *l, struct sk_buff *skb,
1117 			    struct sk_buff_head *inputq)
1118 {
1119 	struct sk_buff_head *mc_inputq = l->bc_rcvlink->inputq;
1120 	struct tipc_msg *hdr = buf_msg(skb);
1121 
1122 	switch (msg_user(hdr)) {
1123 	case TIPC_LOW_IMPORTANCE:
1124 	case TIPC_MEDIUM_IMPORTANCE:
1125 	case TIPC_HIGH_IMPORTANCE:
1126 	case TIPC_CRITICAL_IMPORTANCE:
1127 		if (unlikely(msg_in_group(hdr) || msg_mcast(hdr))) {
1128 			skb_queue_tail(mc_inputq, skb);
1129 			return true;
1130 		}
1131 		/* fall through */
1132 	case CONN_MANAGER:
1133 		skb_queue_tail(inputq, skb);
1134 		return true;
1135 	case GROUP_PROTOCOL:
1136 		skb_queue_tail(mc_inputq, skb);
1137 		return true;
1138 	case NAME_DISTRIBUTOR:
1139 		l->bc_rcvlink->state = LINK_ESTABLISHED;
1140 		skb_queue_tail(l->namedq, skb);
1141 		return true;
1142 	case MSG_BUNDLER:
1143 	case TUNNEL_PROTOCOL:
1144 	case MSG_FRAGMENTER:
1145 	case BCAST_PROTOCOL:
1146 		return false;
1147 	default:
1148 		pr_warn("Dropping received illegal msg type\n");
1149 		kfree_skb(skb);
1150 		return true;
1151 	};
1152 }
1153 
1154 /* tipc_link_input - process packet that has passed link protocol check
1155  *
1156  * Consumes buffer
1157  */
1158 static int tipc_link_input(struct tipc_link *l, struct sk_buff *skb,
1159 			   struct sk_buff_head *inputq)
1160 {
1161 	struct tipc_msg *hdr = buf_msg(skb);
1162 	struct sk_buff **reasm_skb = &l->reasm_buf;
1163 	struct sk_buff *iskb;
1164 	struct sk_buff_head tmpq;
1165 	int usr = msg_user(hdr);
1166 	int rc = 0;
1167 	int pos = 0;
1168 	int ipos = 0;
1169 
1170 	if (unlikely(usr == TUNNEL_PROTOCOL)) {
1171 		if (msg_type(hdr) == SYNCH_MSG) {
1172 			__skb_queue_purge(&l->deferdq);
1173 			goto drop;
1174 		}
1175 		if (!tipc_msg_extract(skb, &iskb, &ipos))
1176 			return rc;
1177 		kfree_skb(skb);
1178 		skb = iskb;
1179 		hdr = buf_msg(skb);
1180 		if (less(msg_seqno(hdr), l->drop_point))
1181 			goto drop;
1182 		if (tipc_data_input(l, skb, inputq))
1183 			return rc;
1184 		usr = msg_user(hdr);
1185 		reasm_skb = &l->failover_reasm_skb;
1186 	}
1187 
1188 	if (usr == MSG_BUNDLER) {
1189 		skb_queue_head_init(&tmpq);
1190 		l->stats.recv_bundles++;
1191 		l->stats.recv_bundled += msg_msgcnt(hdr);
1192 		while (tipc_msg_extract(skb, &iskb, &pos))
1193 			tipc_data_input(l, iskb, &tmpq);
1194 		tipc_skb_queue_splice_tail(&tmpq, inputq);
1195 		return 0;
1196 	} else if (usr == MSG_FRAGMENTER) {
1197 		l->stats.recv_fragments++;
1198 		if (tipc_buf_append(reasm_skb, &skb)) {
1199 			l->stats.recv_fragmented++;
1200 			tipc_data_input(l, skb, inputq);
1201 		} else if (!*reasm_skb && !link_is_bc_rcvlink(l)) {
1202 			pr_warn_ratelimited("Unable to build fragment list\n");
1203 			return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1204 		}
1205 		return 0;
1206 	} else if (usr == BCAST_PROTOCOL) {
1207 		tipc_bcast_lock(l->net);
1208 		tipc_link_bc_init_rcv(l->bc_rcvlink, hdr);
1209 		tipc_bcast_unlock(l->net);
1210 	}
1211 drop:
1212 	kfree_skb(skb);
1213 	return 0;
1214 }
1215 
1216 static bool tipc_link_release_pkts(struct tipc_link *l, u16 acked)
1217 {
1218 	bool released = false;
1219 	struct sk_buff *skb, *tmp;
1220 
1221 	skb_queue_walk_safe(&l->transmq, skb, tmp) {
1222 		if (more(buf_seqno(skb), acked))
1223 			break;
1224 		__skb_unlink(skb, &l->transmq);
1225 		kfree_skb(skb);
1226 		released = true;
1227 	}
1228 	return released;
1229 }
1230 
1231 /* tipc_link_build_state_msg: prepare link state message for transmission
1232  *
1233  * Note that sending of broadcast ack is coordinated among nodes, to reduce
1234  * risk of ack storms towards the sender
1235  */
1236 int tipc_link_build_state_msg(struct tipc_link *l, struct sk_buff_head *xmitq)
1237 {
1238 	if (!l)
1239 		return 0;
1240 
1241 	/* Broadcast ACK must be sent via a unicast link => defer to caller */
1242 	if (link_is_bc_rcvlink(l)) {
1243 		if (((l->rcv_nxt ^ tipc_own_addr(l->net)) & 0xf) != 0xf)
1244 			return 0;
1245 		l->rcv_unacked = 0;
1246 
1247 		/* Use snd_nxt to store peer's snd_nxt in broadcast rcv link */
1248 		l->snd_nxt = l->rcv_nxt;
1249 		return TIPC_LINK_SND_STATE;
1250 	}
1251 
1252 	/* Unicast ACK */
1253 	l->rcv_unacked = 0;
1254 	l->stats.sent_acks++;
1255 	tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, 0, 0, xmitq);
1256 	return 0;
1257 }
1258 
1259 /* tipc_link_build_reset_msg: prepare link RESET or ACTIVATE message
1260  */
1261 void tipc_link_build_reset_msg(struct tipc_link *l, struct sk_buff_head *xmitq)
1262 {
1263 	int mtyp = RESET_MSG;
1264 	struct sk_buff *skb;
1265 
1266 	if (l->state == LINK_ESTABLISHING)
1267 		mtyp = ACTIVATE_MSG;
1268 
1269 	tipc_link_build_proto_msg(l, mtyp, 0, 0, 0, 0, 0, xmitq);
1270 
1271 	/* Inform peer that this endpoint is going down if applicable */
1272 	skb = skb_peek_tail(xmitq);
1273 	if (skb && (l->state == LINK_RESET))
1274 		msg_set_peer_stopping(buf_msg(skb), 1);
1275 }
1276 
1277 /* tipc_link_build_nack_msg: prepare link nack message for transmission
1278  * Note that sending of broadcast NACK is coordinated among nodes, to
1279  * reduce the risk of NACK storms towards the sender
1280  */
1281 static int tipc_link_build_nack_msg(struct tipc_link *l,
1282 				    struct sk_buff_head *xmitq)
1283 {
1284 	u32 def_cnt = ++l->stats.deferred_recv;
1285 	int match1, match2;
1286 
1287 	if (link_is_bc_rcvlink(l)) {
1288 		match1 = def_cnt & 0xf;
1289 		match2 = tipc_own_addr(l->net) & 0xf;
1290 		if (match1 == match2)
1291 			return TIPC_LINK_SND_STATE;
1292 		return 0;
1293 	}
1294 
1295 	if ((skb_queue_len(&l->deferdq) == 1) || !(def_cnt % TIPC_NACK_INTV))
1296 		tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, 0, 0, xmitq);
1297 	return 0;
1298 }
1299 
1300 /* tipc_link_rcv - process TIPC packets/messages arriving from off-node
1301  * @l: the link that should handle the message
1302  * @skb: TIPC packet
1303  * @xmitq: queue to place packets to be sent after this call
1304  */
1305 int tipc_link_rcv(struct tipc_link *l, struct sk_buff *skb,
1306 		  struct sk_buff_head *xmitq)
1307 {
1308 	struct sk_buff_head *defq = &l->deferdq;
1309 	struct tipc_msg *hdr;
1310 	u16 seqno, rcv_nxt, win_lim;
1311 	int rc = 0;
1312 
1313 	do {
1314 		hdr = buf_msg(skb);
1315 		seqno = msg_seqno(hdr);
1316 		rcv_nxt = l->rcv_nxt;
1317 		win_lim = rcv_nxt + TIPC_MAX_LINK_WIN;
1318 
1319 		/* Verify and update link state */
1320 		if (unlikely(msg_user(hdr) == LINK_PROTOCOL))
1321 			return tipc_link_proto_rcv(l, skb, xmitq);
1322 
1323 		if (unlikely(!link_is_up(l))) {
1324 			if (l->state == LINK_ESTABLISHING)
1325 				rc = TIPC_LINK_UP_EVT;
1326 			goto drop;
1327 		}
1328 
1329 		/* Don't send probe at next timeout expiration */
1330 		l->silent_intv_cnt = 0;
1331 
1332 		/* Drop if outside receive window */
1333 		if (unlikely(less(seqno, rcv_nxt) || more(seqno, win_lim))) {
1334 			l->stats.duplicates++;
1335 			goto drop;
1336 		}
1337 
1338 		/* Forward queues and wake up waiting users */
1339 		if (likely(tipc_link_release_pkts(l, msg_ack(hdr)))) {
1340 			l->stale_cnt = 0;
1341 			tipc_link_advance_backlog(l, xmitq);
1342 			if (unlikely(!skb_queue_empty(&l->wakeupq)))
1343 				link_prepare_wakeup(l);
1344 		}
1345 
1346 		/* Defer delivery if sequence gap */
1347 		if (unlikely(seqno != rcv_nxt)) {
1348 			__tipc_skb_queue_sorted(defq, seqno, skb);
1349 			rc |= tipc_link_build_nack_msg(l, xmitq);
1350 			break;
1351 		}
1352 
1353 		/* Deliver packet */
1354 		l->rcv_nxt++;
1355 		l->stats.recv_pkts++;
1356 		if (!tipc_data_input(l, skb, l->inputq))
1357 			rc |= tipc_link_input(l, skb, l->inputq);
1358 		if (unlikely(++l->rcv_unacked >= TIPC_MIN_LINK_WIN))
1359 			rc |= tipc_link_build_state_msg(l, xmitq);
1360 		if (unlikely(rc & ~TIPC_LINK_SND_STATE))
1361 			break;
1362 	} while ((skb = __skb_dequeue(defq)));
1363 
1364 	return rc;
1365 drop:
1366 	kfree_skb(skb);
1367 	return rc;
1368 }
1369 
1370 static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
1371 				      bool probe_reply, u16 rcvgap,
1372 				      int tolerance, int priority,
1373 				      struct sk_buff_head *xmitq)
1374 {
1375 	struct tipc_link *bcl = l->bc_rcvlink;
1376 	struct sk_buff *skb;
1377 	struct tipc_msg *hdr;
1378 	struct sk_buff_head *dfq = &l->deferdq;
1379 	bool node_up = link_is_up(bcl);
1380 	struct tipc_mon_state *mstate = &l->mon_state;
1381 	int dlen = 0;
1382 	void *data;
1383 
1384 	/* Don't send protocol message during reset or link failover */
1385 	if (tipc_link_is_blocked(l))
1386 		return;
1387 
1388 	if (!tipc_link_is_up(l) && (mtyp == STATE_MSG))
1389 		return;
1390 
1391 	if (!skb_queue_empty(dfq))
1392 		rcvgap = buf_seqno(skb_peek(dfq)) - l->rcv_nxt;
1393 
1394 	skb = tipc_msg_create(LINK_PROTOCOL, mtyp, INT_H_SIZE,
1395 			      tipc_max_domain_size, l->addr,
1396 			      tipc_own_addr(l->net), 0, 0, 0);
1397 	if (!skb)
1398 		return;
1399 
1400 	hdr = buf_msg(skb);
1401 	data = msg_data(hdr);
1402 	msg_set_session(hdr, l->session);
1403 	msg_set_bearer_id(hdr, l->bearer_id);
1404 	msg_set_net_plane(hdr, l->net_plane);
1405 	msg_set_next_sent(hdr, l->snd_nxt);
1406 	msg_set_ack(hdr, l->rcv_nxt - 1);
1407 	msg_set_bcast_ack(hdr, bcl->rcv_nxt - 1);
1408 	msg_set_bc_ack_invalid(hdr, !node_up);
1409 	msg_set_last_bcast(hdr, l->bc_sndlink->snd_nxt - 1);
1410 	msg_set_link_tolerance(hdr, tolerance);
1411 	msg_set_linkprio(hdr, priority);
1412 	msg_set_redundant_link(hdr, node_up);
1413 	msg_set_seq_gap(hdr, 0);
1414 	msg_set_seqno(hdr, l->snd_nxt + U16_MAX / 2);
1415 
1416 	if (mtyp == STATE_MSG) {
1417 		if (l->peer_caps & TIPC_LINK_PROTO_SEQNO)
1418 			msg_set_seqno(hdr, l->snd_nxt_state++);
1419 		msg_set_seq_gap(hdr, rcvgap);
1420 		msg_set_bc_gap(hdr, link_bc_rcv_gap(bcl));
1421 		msg_set_probe(hdr, probe);
1422 		msg_set_is_keepalive(hdr, probe || probe_reply);
1423 		tipc_mon_prep(l->net, data, &dlen, mstate, l->bearer_id);
1424 		msg_set_size(hdr, INT_H_SIZE + dlen);
1425 		skb_trim(skb, INT_H_SIZE + dlen);
1426 		l->stats.sent_states++;
1427 		l->rcv_unacked = 0;
1428 	} else {
1429 		/* RESET_MSG or ACTIVATE_MSG */
1430 		if (mtyp == ACTIVATE_MSG) {
1431 			msg_set_dest_session_valid(hdr, 1);
1432 			msg_set_dest_session(hdr, l->peer_session);
1433 		}
1434 		msg_set_max_pkt(hdr, l->advertised_mtu);
1435 		strcpy(data, l->if_name);
1436 		msg_set_size(hdr, INT_H_SIZE + TIPC_MAX_IF_NAME);
1437 		skb_trim(skb, INT_H_SIZE + TIPC_MAX_IF_NAME);
1438 	}
1439 	if (probe)
1440 		l->stats.sent_probes++;
1441 	if (rcvgap)
1442 		l->stats.sent_nacks++;
1443 	skb->priority = TC_PRIO_CONTROL;
1444 	__skb_queue_tail(xmitq, skb);
1445 	trace_tipc_proto_build(skb, false, l->name);
1446 }
1447 
1448 void tipc_link_create_dummy_tnl_msg(struct tipc_link *l,
1449 				    struct sk_buff_head *xmitq)
1450 {
1451 	u32 onode = tipc_own_addr(l->net);
1452 	struct tipc_msg *hdr, *ihdr;
1453 	struct sk_buff_head tnlq;
1454 	struct sk_buff *skb;
1455 	u32 dnode = l->addr;
1456 
1457 	skb_queue_head_init(&tnlq);
1458 	skb = tipc_msg_create(TUNNEL_PROTOCOL, FAILOVER_MSG,
1459 			      INT_H_SIZE, BASIC_H_SIZE,
1460 			      dnode, onode, 0, 0, 0);
1461 	if (!skb) {
1462 		pr_warn("%sunable to create tunnel packet\n", link_co_err);
1463 		return;
1464 	}
1465 
1466 	hdr = buf_msg(skb);
1467 	msg_set_msgcnt(hdr, 1);
1468 	msg_set_bearer_id(hdr, l->peer_bearer_id);
1469 
1470 	ihdr = (struct tipc_msg *)msg_data(hdr);
1471 	tipc_msg_init(onode, ihdr, TIPC_LOW_IMPORTANCE, TIPC_DIRECT_MSG,
1472 		      BASIC_H_SIZE, dnode);
1473 	msg_set_errcode(ihdr, TIPC_ERR_NO_PORT);
1474 	__skb_queue_tail(&tnlq, skb);
1475 	tipc_link_xmit(l, &tnlq, xmitq);
1476 }
1477 
1478 /* tipc_link_tnl_prepare(): prepare and return a list of tunnel packets
1479  * with contents of the link's transmit and backlog queues.
1480  */
1481 void tipc_link_tnl_prepare(struct tipc_link *l, struct tipc_link *tnl,
1482 			   int mtyp, struct sk_buff_head *xmitq)
1483 {
1484 	struct sk_buff *skb, *tnlskb;
1485 	struct tipc_msg *hdr, tnlhdr;
1486 	struct sk_buff_head *queue = &l->transmq;
1487 	struct sk_buff_head tmpxq, tnlq;
1488 	u16 pktlen, pktcnt, seqno = l->snd_nxt;
1489 
1490 	if (!tnl)
1491 		return;
1492 
1493 	skb_queue_head_init(&tnlq);
1494 	skb_queue_head_init(&tmpxq);
1495 
1496 	/* At least one packet required for safe algorithm => add dummy */
1497 	skb = tipc_msg_create(TIPC_LOW_IMPORTANCE, TIPC_DIRECT_MSG,
1498 			      BASIC_H_SIZE, 0, l->addr, tipc_own_addr(l->net),
1499 			      0, 0, TIPC_ERR_NO_PORT);
1500 	if (!skb) {
1501 		pr_warn("%sunable to create tunnel packet\n", link_co_err);
1502 		return;
1503 	}
1504 	skb_queue_tail(&tnlq, skb);
1505 	tipc_link_xmit(l, &tnlq, &tmpxq);
1506 	__skb_queue_purge(&tmpxq);
1507 
1508 	/* Initialize reusable tunnel packet header */
1509 	tipc_msg_init(tipc_own_addr(l->net), &tnlhdr, TUNNEL_PROTOCOL,
1510 		      mtyp, INT_H_SIZE, l->addr);
1511 	pktcnt = skb_queue_len(&l->transmq) + skb_queue_len(&l->backlogq);
1512 	msg_set_msgcnt(&tnlhdr, pktcnt);
1513 	msg_set_bearer_id(&tnlhdr, l->peer_bearer_id);
1514 tnl:
1515 	/* Wrap each packet into a tunnel packet */
1516 	skb_queue_walk(queue, skb) {
1517 		hdr = buf_msg(skb);
1518 		if (queue == &l->backlogq)
1519 			msg_set_seqno(hdr, seqno++);
1520 		pktlen = msg_size(hdr);
1521 		msg_set_size(&tnlhdr, pktlen + INT_H_SIZE);
1522 		tnlskb = tipc_buf_acquire(pktlen + INT_H_SIZE, GFP_ATOMIC);
1523 		if (!tnlskb) {
1524 			pr_warn("%sunable to send packet\n", link_co_err);
1525 			return;
1526 		}
1527 		skb_copy_to_linear_data(tnlskb, &tnlhdr, INT_H_SIZE);
1528 		skb_copy_to_linear_data_offset(tnlskb, INT_H_SIZE, hdr, pktlen);
1529 		__skb_queue_tail(&tnlq, tnlskb);
1530 	}
1531 	if (queue != &l->backlogq) {
1532 		queue = &l->backlogq;
1533 		goto tnl;
1534 	}
1535 
1536 	tipc_link_xmit(tnl, &tnlq, xmitq);
1537 
1538 	if (mtyp == FAILOVER_MSG) {
1539 		tnl->drop_point = l->rcv_nxt;
1540 		tnl->failover_reasm_skb = l->reasm_buf;
1541 		l->reasm_buf = NULL;
1542 	}
1543 }
1544 
1545 /* tipc_link_validate_msg(): validate message against current link state
1546  * Returns true if message should be accepted, otherwise false
1547  */
1548 bool tipc_link_validate_msg(struct tipc_link *l, struct tipc_msg *hdr)
1549 {
1550 	u16 curr_session = l->peer_session;
1551 	u16 session = msg_session(hdr);
1552 	int mtyp = msg_type(hdr);
1553 
1554 	if (msg_user(hdr) != LINK_PROTOCOL)
1555 		return true;
1556 
1557 	switch (mtyp) {
1558 	case RESET_MSG:
1559 		if (!l->in_session)
1560 			return true;
1561 		/* Accept only RESET with new session number */
1562 		return more(session, curr_session);
1563 	case ACTIVATE_MSG:
1564 		if (!l->in_session)
1565 			return true;
1566 		/* Accept only ACTIVATE with new or current session number */
1567 		return !less(session, curr_session);
1568 	case STATE_MSG:
1569 		/* Accept only STATE with current session number */
1570 		if (!l->in_session)
1571 			return false;
1572 		if (session != curr_session)
1573 			return false;
1574 		/* Extra sanity check */
1575 		if (!link_is_up(l) && msg_ack(hdr))
1576 			return false;
1577 		if (!(l->peer_caps & TIPC_LINK_PROTO_SEQNO))
1578 			return true;
1579 		/* Accept only STATE with new sequence number */
1580 		return !less(msg_seqno(hdr), l->rcv_nxt_state);
1581 	default:
1582 		return false;
1583 	}
1584 }
1585 
1586 /* tipc_link_proto_rcv(): receive link level protocol message :
1587  * Note that network plane id propagates through the network, and may
1588  * change at any time. The node with lowest numerical id determines
1589  * network plane
1590  */
1591 static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
1592 			       struct sk_buff_head *xmitq)
1593 {
1594 	struct tipc_msg *hdr = buf_msg(skb);
1595 	u16 rcvgap = 0;
1596 	u16 ack = msg_ack(hdr);
1597 	u16 gap = msg_seq_gap(hdr);
1598 	u16 peers_snd_nxt =  msg_next_sent(hdr);
1599 	u16 peers_tol = msg_link_tolerance(hdr);
1600 	u16 peers_prio = msg_linkprio(hdr);
1601 	u16 rcv_nxt = l->rcv_nxt;
1602 	u16 dlen = msg_data_sz(hdr);
1603 	int mtyp = msg_type(hdr);
1604 	bool reply = msg_probe(hdr);
1605 	void *data;
1606 	char *if_name;
1607 	int rc = 0;
1608 
1609 	trace_tipc_proto_rcv(skb, false, l->name);
1610 	if (tipc_link_is_blocked(l) || !xmitq)
1611 		goto exit;
1612 
1613 	if (tipc_own_addr(l->net) > msg_prevnode(hdr))
1614 		l->net_plane = msg_net_plane(hdr);
1615 
1616 	skb_linearize(skb);
1617 	hdr = buf_msg(skb);
1618 	data = msg_data(hdr);
1619 
1620 	if (!tipc_link_validate_msg(l, hdr)) {
1621 		trace_tipc_skb_dump(skb, false, "PROTO invalid (1)!");
1622 		trace_tipc_link_dump(l, TIPC_DUMP_NONE, "PROTO invalid (1)!");
1623 		goto exit;
1624 	}
1625 
1626 	switch (mtyp) {
1627 	case RESET_MSG:
1628 	case ACTIVATE_MSG:
1629 		/* Complete own link name with peer's interface name */
1630 		if_name =  strrchr(l->name, ':') + 1;
1631 		if (sizeof(l->name) - (if_name - l->name) <= TIPC_MAX_IF_NAME)
1632 			break;
1633 		if (msg_data_sz(hdr) < TIPC_MAX_IF_NAME)
1634 			break;
1635 		strncpy(if_name, data, TIPC_MAX_IF_NAME);
1636 
1637 		/* Update own tolerance if peer indicates a non-zero value */
1638 		if (in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL)) {
1639 			l->tolerance = peers_tol;
1640 			l->bc_rcvlink->tolerance = peers_tol;
1641 		}
1642 		/* Update own priority if peer's priority is higher */
1643 		if (in_range(peers_prio, l->priority + 1, TIPC_MAX_LINK_PRI))
1644 			l->priority = peers_prio;
1645 
1646 		/* If peer is going down we want full re-establish cycle */
1647 		if (msg_peer_stopping(hdr)) {
1648 			rc = tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1649 			break;
1650 		}
1651 
1652 		/* If this endpoint was re-created while peer was ESTABLISHING
1653 		 * it doesn't know current session number. Force re-synch.
1654 		 */
1655 		if (mtyp == ACTIVATE_MSG && msg_dest_session_valid(hdr) &&
1656 		    l->session != msg_dest_session(hdr)) {
1657 			if (less(l->session, msg_dest_session(hdr)))
1658 				l->session = msg_dest_session(hdr) + 1;
1659 			break;
1660 		}
1661 
1662 		/* ACTIVATE_MSG serves as PEER_RESET if link is already down */
1663 		if (mtyp == RESET_MSG || !link_is_up(l))
1664 			rc = tipc_link_fsm_evt(l, LINK_PEER_RESET_EVT);
1665 
1666 		/* ACTIVATE_MSG takes up link if it was already locally reset */
1667 		if (mtyp == ACTIVATE_MSG && l->state == LINK_ESTABLISHING)
1668 			rc = TIPC_LINK_UP_EVT;
1669 
1670 		l->peer_session = msg_session(hdr);
1671 		l->in_session = true;
1672 		l->peer_bearer_id = msg_bearer_id(hdr);
1673 		if (l->mtu > msg_max_pkt(hdr))
1674 			l->mtu = msg_max_pkt(hdr);
1675 		break;
1676 
1677 	case STATE_MSG:
1678 		l->rcv_nxt_state = msg_seqno(hdr) + 1;
1679 
1680 		/* Update own tolerance if peer indicates a non-zero value */
1681 		if (in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL)) {
1682 			l->tolerance = peers_tol;
1683 			l->bc_rcvlink->tolerance = peers_tol;
1684 		}
1685 		/* Update own prio if peer indicates a different value */
1686 		if ((peers_prio != l->priority) &&
1687 		    in_range(peers_prio, 1, TIPC_MAX_LINK_PRI)) {
1688 			l->priority = peers_prio;
1689 			rc = tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1690 		}
1691 
1692 		l->silent_intv_cnt = 0;
1693 		l->stats.recv_states++;
1694 		if (msg_probe(hdr))
1695 			l->stats.recv_probes++;
1696 
1697 		if (!link_is_up(l)) {
1698 			if (l->state == LINK_ESTABLISHING)
1699 				rc = TIPC_LINK_UP_EVT;
1700 			break;
1701 		}
1702 		tipc_mon_rcv(l->net, data, dlen, l->addr,
1703 			     &l->mon_state, l->bearer_id);
1704 
1705 		/* Send NACK if peer has sent pkts we haven't received yet */
1706 		if (more(peers_snd_nxt, rcv_nxt) && !tipc_link_is_synching(l))
1707 			rcvgap = peers_snd_nxt - l->rcv_nxt;
1708 		if (rcvgap || reply)
1709 			tipc_link_build_proto_msg(l, STATE_MSG, 0, reply,
1710 						  rcvgap, 0, 0, xmitq);
1711 		tipc_link_release_pkts(l, ack);
1712 
1713 		/* If NACK, retransmit will now start at right position */
1714 		if (gap) {
1715 			rc = tipc_link_retrans(l, l, ack + 1, ack + gap, xmitq);
1716 			l->stats.recv_nacks++;
1717 		}
1718 
1719 		tipc_link_advance_backlog(l, xmitq);
1720 		if (unlikely(!skb_queue_empty(&l->wakeupq)))
1721 			link_prepare_wakeup(l);
1722 	}
1723 exit:
1724 	kfree_skb(skb);
1725 	return rc;
1726 }
1727 
1728 /* tipc_link_build_bc_proto_msg() - create broadcast protocol message
1729  */
1730 static bool tipc_link_build_bc_proto_msg(struct tipc_link *l, bool bcast,
1731 					 u16 peers_snd_nxt,
1732 					 struct sk_buff_head *xmitq)
1733 {
1734 	struct sk_buff *skb;
1735 	struct tipc_msg *hdr;
1736 	struct sk_buff *dfrd_skb = skb_peek(&l->deferdq);
1737 	u16 ack = l->rcv_nxt - 1;
1738 	u16 gap_to = peers_snd_nxt - 1;
1739 
1740 	skb = tipc_msg_create(BCAST_PROTOCOL, STATE_MSG, INT_H_SIZE,
1741 			      0, l->addr, tipc_own_addr(l->net), 0, 0, 0);
1742 	if (!skb)
1743 		return false;
1744 	hdr = buf_msg(skb);
1745 	msg_set_last_bcast(hdr, l->bc_sndlink->snd_nxt - 1);
1746 	msg_set_bcast_ack(hdr, ack);
1747 	msg_set_bcgap_after(hdr, ack);
1748 	if (dfrd_skb)
1749 		gap_to = buf_seqno(dfrd_skb) - 1;
1750 	msg_set_bcgap_to(hdr, gap_to);
1751 	msg_set_non_seq(hdr, bcast);
1752 	__skb_queue_tail(xmitq, skb);
1753 	return true;
1754 }
1755 
1756 /* tipc_link_build_bc_init_msg() - synchronize broadcast link endpoints.
1757  *
1758  * Give a newly added peer node the sequence number where it should
1759  * start receiving and acking broadcast packets.
1760  */
1761 static void tipc_link_build_bc_init_msg(struct tipc_link *l,
1762 					struct sk_buff_head *xmitq)
1763 {
1764 	struct sk_buff_head list;
1765 
1766 	__skb_queue_head_init(&list);
1767 	if (!tipc_link_build_bc_proto_msg(l->bc_rcvlink, false, 0, &list))
1768 		return;
1769 	msg_set_bc_ack_invalid(buf_msg(skb_peek(&list)), true);
1770 	tipc_link_xmit(l, &list, xmitq);
1771 }
1772 
1773 /* tipc_link_bc_init_rcv - receive initial broadcast synch data from peer
1774  */
1775 void tipc_link_bc_init_rcv(struct tipc_link *l, struct tipc_msg *hdr)
1776 {
1777 	int mtyp = msg_type(hdr);
1778 	u16 peers_snd_nxt = msg_bc_snd_nxt(hdr);
1779 
1780 	if (link_is_up(l))
1781 		return;
1782 
1783 	if (msg_user(hdr) == BCAST_PROTOCOL) {
1784 		l->rcv_nxt = peers_snd_nxt;
1785 		l->state = LINK_ESTABLISHED;
1786 		return;
1787 	}
1788 
1789 	if (l->peer_caps & TIPC_BCAST_SYNCH)
1790 		return;
1791 
1792 	if (msg_peer_node_is_up(hdr))
1793 		return;
1794 
1795 	/* Compatibility: accept older, less safe initial synch data */
1796 	if ((mtyp == RESET_MSG) || (mtyp == ACTIVATE_MSG))
1797 		l->rcv_nxt = peers_snd_nxt;
1798 }
1799 
1800 /* tipc_link_bc_sync_rcv - update rcv link according to peer's send state
1801  */
1802 int tipc_link_bc_sync_rcv(struct tipc_link *l, struct tipc_msg *hdr,
1803 			  struct sk_buff_head *xmitq)
1804 {
1805 	struct tipc_link *snd_l = l->bc_sndlink;
1806 	u16 peers_snd_nxt = msg_bc_snd_nxt(hdr);
1807 	u16 from = msg_bcast_ack(hdr) + 1;
1808 	u16 to = from + msg_bc_gap(hdr) - 1;
1809 	int rc = 0;
1810 
1811 	if (!link_is_up(l))
1812 		return rc;
1813 
1814 	if (!msg_peer_node_is_up(hdr))
1815 		return rc;
1816 
1817 	/* Open when peer ackowledges our bcast init msg (pkt #1) */
1818 	if (msg_ack(hdr))
1819 		l->bc_peer_is_up = true;
1820 
1821 	if (!l->bc_peer_is_up)
1822 		return rc;
1823 
1824 	l->stats.recv_nacks++;
1825 
1826 	/* Ignore if peers_snd_nxt goes beyond receive window */
1827 	if (more(peers_snd_nxt, l->rcv_nxt + l->window))
1828 		return rc;
1829 
1830 	rc = tipc_link_retrans(snd_l, l, from, to, xmitq);
1831 
1832 	l->snd_nxt = peers_snd_nxt;
1833 	if (link_bc_rcv_gap(l))
1834 		rc |= TIPC_LINK_SND_STATE;
1835 
1836 	/* Return now if sender supports nack via STATE messages */
1837 	if (l->peer_caps & TIPC_BCAST_STATE_NACK)
1838 		return rc;
1839 
1840 	/* Otherwise, be backwards compatible */
1841 
1842 	if (!more(peers_snd_nxt, l->rcv_nxt)) {
1843 		l->nack_state = BC_NACK_SND_CONDITIONAL;
1844 		return 0;
1845 	}
1846 
1847 	/* Don't NACK if one was recently sent or peeked */
1848 	if (l->nack_state == BC_NACK_SND_SUPPRESS) {
1849 		l->nack_state = BC_NACK_SND_UNCONDITIONAL;
1850 		return 0;
1851 	}
1852 
1853 	/* Conditionally delay NACK sending until next synch rcv */
1854 	if (l->nack_state == BC_NACK_SND_CONDITIONAL) {
1855 		l->nack_state = BC_NACK_SND_UNCONDITIONAL;
1856 		if ((peers_snd_nxt - l->rcv_nxt) < TIPC_MIN_LINK_WIN)
1857 			return 0;
1858 	}
1859 
1860 	/* Send NACK now but suppress next one */
1861 	tipc_link_build_bc_proto_msg(l, true, peers_snd_nxt, xmitq);
1862 	l->nack_state = BC_NACK_SND_SUPPRESS;
1863 	return 0;
1864 }
1865 
1866 void tipc_link_bc_ack_rcv(struct tipc_link *l, u16 acked,
1867 			  struct sk_buff_head *xmitq)
1868 {
1869 	struct sk_buff *skb, *tmp;
1870 	struct tipc_link *snd_l = l->bc_sndlink;
1871 
1872 	if (!link_is_up(l) || !l->bc_peer_is_up)
1873 		return;
1874 
1875 	if (!more(acked, l->acked))
1876 		return;
1877 
1878 	trace_tipc_link_bc_ack(l, l->acked, acked, &snd_l->transmq);
1879 	/* Skip over packets peer has already acked */
1880 	skb_queue_walk(&snd_l->transmq, skb) {
1881 		if (more(buf_seqno(skb), l->acked))
1882 			break;
1883 	}
1884 
1885 	/* Update/release the packets peer is acking now */
1886 	skb_queue_walk_from_safe(&snd_l->transmq, skb, tmp) {
1887 		if (more(buf_seqno(skb), acked))
1888 			break;
1889 		if (!--TIPC_SKB_CB(skb)->ackers) {
1890 			__skb_unlink(skb, &snd_l->transmq);
1891 			kfree_skb(skb);
1892 		}
1893 	}
1894 	l->acked = acked;
1895 	tipc_link_advance_backlog(snd_l, xmitq);
1896 	if (unlikely(!skb_queue_empty(&snd_l->wakeupq)))
1897 		link_prepare_wakeup(snd_l);
1898 }
1899 
1900 /* tipc_link_bc_nack_rcv(): receive broadcast nack message
1901  * This function is here for backwards compatibility, since
1902  * no BCAST_PROTOCOL/STATE messages occur from TIPC v2.5.
1903  */
1904 int tipc_link_bc_nack_rcv(struct tipc_link *l, struct sk_buff *skb,
1905 			  struct sk_buff_head *xmitq)
1906 {
1907 	struct tipc_msg *hdr = buf_msg(skb);
1908 	u32 dnode = msg_destnode(hdr);
1909 	int mtyp = msg_type(hdr);
1910 	u16 acked = msg_bcast_ack(hdr);
1911 	u16 from = acked + 1;
1912 	u16 to = msg_bcgap_to(hdr);
1913 	u16 peers_snd_nxt = to + 1;
1914 	int rc = 0;
1915 
1916 	kfree_skb(skb);
1917 
1918 	if (!tipc_link_is_up(l) || !l->bc_peer_is_up)
1919 		return 0;
1920 
1921 	if (mtyp != STATE_MSG)
1922 		return 0;
1923 
1924 	if (dnode == tipc_own_addr(l->net)) {
1925 		tipc_link_bc_ack_rcv(l, acked, xmitq);
1926 		rc = tipc_link_retrans(l->bc_sndlink, l, from, to, xmitq);
1927 		l->stats.recv_nacks++;
1928 		return rc;
1929 	}
1930 
1931 	/* Msg for other node => suppress own NACK at next sync if applicable */
1932 	if (more(peers_snd_nxt, l->rcv_nxt) && !less(l->rcv_nxt, from))
1933 		l->nack_state = BC_NACK_SND_SUPPRESS;
1934 
1935 	return 0;
1936 }
1937 
1938 void tipc_link_set_queue_limits(struct tipc_link *l, u32 win)
1939 {
1940 	int max_bulk = TIPC_MAX_PUBL / (l->mtu / ITEM_SIZE);
1941 
1942 	l->window = win;
1943 	l->backlog[TIPC_LOW_IMPORTANCE].limit      = max_t(u16, 50, win);
1944 	l->backlog[TIPC_MEDIUM_IMPORTANCE].limit   = max_t(u16, 100, win * 2);
1945 	l->backlog[TIPC_HIGH_IMPORTANCE].limit     = max_t(u16, 150, win * 3);
1946 	l->backlog[TIPC_CRITICAL_IMPORTANCE].limit = max_t(u16, 200, win * 4);
1947 	l->backlog[TIPC_SYSTEM_IMPORTANCE].limit   = max_bulk;
1948 }
1949 
1950 /**
1951  * link_reset_stats - reset link statistics
1952  * @l: pointer to link
1953  */
1954 void tipc_link_reset_stats(struct tipc_link *l)
1955 {
1956 	memset(&l->stats, 0, sizeof(l->stats));
1957 }
1958 
1959 static void link_print(struct tipc_link *l, const char *str)
1960 {
1961 	struct sk_buff *hskb = skb_peek(&l->transmq);
1962 	u16 head = hskb ? msg_seqno(buf_msg(hskb)) : l->snd_nxt - 1;
1963 	u16 tail = l->snd_nxt - 1;
1964 
1965 	pr_info("%s Link <%s> state %x\n", str, l->name, l->state);
1966 	pr_info("XMTQ: %u [%u-%u], BKLGQ: %u, SNDNX: %u, RCVNX: %u\n",
1967 		skb_queue_len(&l->transmq), head, tail,
1968 		skb_queue_len(&l->backlogq), l->snd_nxt, l->rcv_nxt);
1969 }
1970 
1971 /* Parse and validate nested (link) properties valid for media, bearer and link
1972  */
1973 int tipc_nl_parse_link_prop(struct nlattr *prop, struct nlattr *props[])
1974 {
1975 	int err;
1976 
1977 	err = nla_parse_nested(props, TIPC_NLA_PROP_MAX, prop,
1978 			       tipc_nl_prop_policy, NULL);
1979 	if (err)
1980 		return err;
1981 
1982 	if (props[TIPC_NLA_PROP_PRIO]) {
1983 		u32 prio;
1984 
1985 		prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
1986 		if (prio > TIPC_MAX_LINK_PRI)
1987 			return -EINVAL;
1988 	}
1989 
1990 	if (props[TIPC_NLA_PROP_TOL]) {
1991 		u32 tol;
1992 
1993 		tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
1994 		if ((tol < TIPC_MIN_LINK_TOL) || (tol > TIPC_MAX_LINK_TOL))
1995 			return -EINVAL;
1996 	}
1997 
1998 	if (props[TIPC_NLA_PROP_WIN]) {
1999 		u32 win;
2000 
2001 		win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
2002 		if ((win < TIPC_MIN_LINK_WIN) || (win > TIPC_MAX_LINK_WIN))
2003 			return -EINVAL;
2004 	}
2005 
2006 	return 0;
2007 }
2008 
2009 static int __tipc_nl_add_stats(struct sk_buff *skb, struct tipc_stats *s)
2010 {
2011 	int i;
2012 	struct nlattr *stats;
2013 
2014 	struct nla_map {
2015 		u32 key;
2016 		u32 val;
2017 	};
2018 
2019 	struct nla_map map[] = {
2020 		{TIPC_NLA_STATS_RX_INFO, 0},
2021 		{TIPC_NLA_STATS_RX_FRAGMENTS, s->recv_fragments},
2022 		{TIPC_NLA_STATS_RX_FRAGMENTED, s->recv_fragmented},
2023 		{TIPC_NLA_STATS_RX_BUNDLES, s->recv_bundles},
2024 		{TIPC_NLA_STATS_RX_BUNDLED, s->recv_bundled},
2025 		{TIPC_NLA_STATS_TX_INFO, 0},
2026 		{TIPC_NLA_STATS_TX_FRAGMENTS, s->sent_fragments},
2027 		{TIPC_NLA_STATS_TX_FRAGMENTED, s->sent_fragmented},
2028 		{TIPC_NLA_STATS_TX_BUNDLES, s->sent_bundles},
2029 		{TIPC_NLA_STATS_TX_BUNDLED, s->sent_bundled},
2030 		{TIPC_NLA_STATS_MSG_PROF_TOT, (s->msg_length_counts) ?
2031 			s->msg_length_counts : 1},
2032 		{TIPC_NLA_STATS_MSG_LEN_CNT, s->msg_length_counts},
2033 		{TIPC_NLA_STATS_MSG_LEN_TOT, s->msg_lengths_total},
2034 		{TIPC_NLA_STATS_MSG_LEN_P0, s->msg_length_profile[0]},
2035 		{TIPC_NLA_STATS_MSG_LEN_P1, s->msg_length_profile[1]},
2036 		{TIPC_NLA_STATS_MSG_LEN_P2, s->msg_length_profile[2]},
2037 		{TIPC_NLA_STATS_MSG_LEN_P3, s->msg_length_profile[3]},
2038 		{TIPC_NLA_STATS_MSG_LEN_P4, s->msg_length_profile[4]},
2039 		{TIPC_NLA_STATS_MSG_LEN_P5, s->msg_length_profile[5]},
2040 		{TIPC_NLA_STATS_MSG_LEN_P6, s->msg_length_profile[6]},
2041 		{TIPC_NLA_STATS_RX_STATES, s->recv_states},
2042 		{TIPC_NLA_STATS_RX_PROBES, s->recv_probes},
2043 		{TIPC_NLA_STATS_RX_NACKS, s->recv_nacks},
2044 		{TIPC_NLA_STATS_RX_DEFERRED, s->deferred_recv},
2045 		{TIPC_NLA_STATS_TX_STATES, s->sent_states},
2046 		{TIPC_NLA_STATS_TX_PROBES, s->sent_probes},
2047 		{TIPC_NLA_STATS_TX_NACKS, s->sent_nacks},
2048 		{TIPC_NLA_STATS_TX_ACKS, s->sent_acks},
2049 		{TIPC_NLA_STATS_RETRANSMITTED, s->retransmitted},
2050 		{TIPC_NLA_STATS_DUPLICATES, s->duplicates},
2051 		{TIPC_NLA_STATS_LINK_CONGS, s->link_congs},
2052 		{TIPC_NLA_STATS_MAX_QUEUE, s->max_queue_sz},
2053 		{TIPC_NLA_STATS_AVG_QUEUE, s->queue_sz_counts ?
2054 			(s->accu_queue_sz / s->queue_sz_counts) : 0}
2055 	};
2056 
2057 	stats = nla_nest_start(skb, TIPC_NLA_LINK_STATS);
2058 	if (!stats)
2059 		return -EMSGSIZE;
2060 
2061 	for (i = 0; i <  ARRAY_SIZE(map); i++)
2062 		if (nla_put_u32(skb, map[i].key, map[i].val))
2063 			goto msg_full;
2064 
2065 	nla_nest_end(skb, stats);
2066 
2067 	return 0;
2068 msg_full:
2069 	nla_nest_cancel(skb, stats);
2070 
2071 	return -EMSGSIZE;
2072 }
2073 
2074 /* Caller should hold appropriate locks to protect the link */
2075 int __tipc_nl_add_link(struct net *net, struct tipc_nl_msg *msg,
2076 		       struct tipc_link *link, int nlflags)
2077 {
2078 	u32 self = tipc_own_addr(net);
2079 	struct nlattr *attrs;
2080 	struct nlattr *prop;
2081 	void *hdr;
2082 	int err;
2083 
2084 	hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
2085 			  nlflags, TIPC_NL_LINK_GET);
2086 	if (!hdr)
2087 		return -EMSGSIZE;
2088 
2089 	attrs = nla_nest_start(msg->skb, TIPC_NLA_LINK);
2090 	if (!attrs)
2091 		goto msg_full;
2092 
2093 	if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, link->name))
2094 		goto attr_msg_full;
2095 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_DEST, tipc_cluster_mask(self)))
2096 		goto attr_msg_full;
2097 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_MTU, link->mtu))
2098 		goto attr_msg_full;
2099 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, link->stats.recv_pkts))
2100 		goto attr_msg_full;
2101 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, link->stats.sent_pkts))
2102 		goto attr_msg_full;
2103 
2104 	if (tipc_link_is_up(link))
2105 		if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
2106 			goto attr_msg_full;
2107 	if (link->active)
2108 		if (nla_put_flag(msg->skb, TIPC_NLA_LINK_ACTIVE))
2109 			goto attr_msg_full;
2110 
2111 	prop = nla_nest_start(msg->skb, TIPC_NLA_LINK_PROP);
2112 	if (!prop)
2113 		goto attr_msg_full;
2114 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
2115 		goto prop_msg_full;
2116 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_TOL, link->tolerance))
2117 		goto prop_msg_full;
2118 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN,
2119 			link->window))
2120 		goto prop_msg_full;
2121 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
2122 		goto prop_msg_full;
2123 	nla_nest_end(msg->skb, prop);
2124 
2125 	err = __tipc_nl_add_stats(msg->skb, &link->stats);
2126 	if (err)
2127 		goto attr_msg_full;
2128 
2129 	nla_nest_end(msg->skb, attrs);
2130 	genlmsg_end(msg->skb, hdr);
2131 
2132 	return 0;
2133 
2134 prop_msg_full:
2135 	nla_nest_cancel(msg->skb, prop);
2136 attr_msg_full:
2137 	nla_nest_cancel(msg->skb, attrs);
2138 msg_full:
2139 	genlmsg_cancel(msg->skb, hdr);
2140 
2141 	return -EMSGSIZE;
2142 }
2143 
2144 static int __tipc_nl_add_bc_link_stat(struct sk_buff *skb,
2145 				      struct tipc_stats *stats)
2146 {
2147 	int i;
2148 	struct nlattr *nest;
2149 
2150 	struct nla_map {
2151 		__u32 key;
2152 		__u32 val;
2153 	};
2154 
2155 	struct nla_map map[] = {
2156 		{TIPC_NLA_STATS_RX_INFO, stats->recv_pkts},
2157 		{TIPC_NLA_STATS_RX_FRAGMENTS, stats->recv_fragments},
2158 		{TIPC_NLA_STATS_RX_FRAGMENTED, stats->recv_fragmented},
2159 		{TIPC_NLA_STATS_RX_BUNDLES, stats->recv_bundles},
2160 		{TIPC_NLA_STATS_RX_BUNDLED, stats->recv_bundled},
2161 		{TIPC_NLA_STATS_TX_INFO, stats->sent_pkts},
2162 		{TIPC_NLA_STATS_TX_FRAGMENTS, stats->sent_fragments},
2163 		{TIPC_NLA_STATS_TX_FRAGMENTED, stats->sent_fragmented},
2164 		{TIPC_NLA_STATS_TX_BUNDLES, stats->sent_bundles},
2165 		{TIPC_NLA_STATS_TX_BUNDLED, stats->sent_bundled},
2166 		{TIPC_NLA_STATS_RX_NACKS, stats->recv_nacks},
2167 		{TIPC_NLA_STATS_RX_DEFERRED, stats->deferred_recv},
2168 		{TIPC_NLA_STATS_TX_NACKS, stats->sent_nacks},
2169 		{TIPC_NLA_STATS_TX_ACKS, stats->sent_acks},
2170 		{TIPC_NLA_STATS_RETRANSMITTED, stats->retransmitted},
2171 		{TIPC_NLA_STATS_DUPLICATES, stats->duplicates},
2172 		{TIPC_NLA_STATS_LINK_CONGS, stats->link_congs},
2173 		{TIPC_NLA_STATS_MAX_QUEUE, stats->max_queue_sz},
2174 		{TIPC_NLA_STATS_AVG_QUEUE, stats->queue_sz_counts ?
2175 			(stats->accu_queue_sz / stats->queue_sz_counts) : 0}
2176 	};
2177 
2178 	nest = nla_nest_start(skb, TIPC_NLA_LINK_STATS);
2179 	if (!nest)
2180 		return -EMSGSIZE;
2181 
2182 	for (i = 0; i <  ARRAY_SIZE(map); i++)
2183 		if (nla_put_u32(skb, map[i].key, map[i].val))
2184 			goto msg_full;
2185 
2186 	nla_nest_end(skb, nest);
2187 
2188 	return 0;
2189 msg_full:
2190 	nla_nest_cancel(skb, nest);
2191 
2192 	return -EMSGSIZE;
2193 }
2194 
2195 int tipc_nl_add_bc_link(struct net *net, struct tipc_nl_msg *msg)
2196 {
2197 	int err;
2198 	void *hdr;
2199 	struct nlattr *attrs;
2200 	struct nlattr *prop;
2201 	struct tipc_net *tn = net_generic(net, tipc_net_id);
2202 	struct tipc_link *bcl = tn->bcl;
2203 
2204 	if (!bcl)
2205 		return 0;
2206 
2207 	tipc_bcast_lock(net);
2208 
2209 	hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
2210 			  NLM_F_MULTI, TIPC_NL_LINK_GET);
2211 	if (!hdr) {
2212 		tipc_bcast_unlock(net);
2213 		return -EMSGSIZE;
2214 	}
2215 
2216 	attrs = nla_nest_start(msg->skb, TIPC_NLA_LINK);
2217 	if (!attrs)
2218 		goto msg_full;
2219 
2220 	/* The broadcast link is always up */
2221 	if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
2222 		goto attr_msg_full;
2223 
2224 	if (nla_put_flag(msg->skb, TIPC_NLA_LINK_BROADCAST))
2225 		goto attr_msg_full;
2226 	if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, bcl->name))
2227 		goto attr_msg_full;
2228 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, 0))
2229 		goto attr_msg_full;
2230 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, 0))
2231 		goto attr_msg_full;
2232 
2233 	prop = nla_nest_start(msg->skb, TIPC_NLA_LINK_PROP);
2234 	if (!prop)
2235 		goto attr_msg_full;
2236 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN, bcl->window))
2237 		goto prop_msg_full;
2238 	nla_nest_end(msg->skb, prop);
2239 
2240 	err = __tipc_nl_add_bc_link_stat(msg->skb, &bcl->stats);
2241 	if (err)
2242 		goto attr_msg_full;
2243 
2244 	tipc_bcast_unlock(net);
2245 	nla_nest_end(msg->skb, attrs);
2246 	genlmsg_end(msg->skb, hdr);
2247 
2248 	return 0;
2249 
2250 prop_msg_full:
2251 	nla_nest_cancel(msg->skb, prop);
2252 attr_msg_full:
2253 	nla_nest_cancel(msg->skb, attrs);
2254 msg_full:
2255 	tipc_bcast_unlock(net);
2256 	genlmsg_cancel(msg->skb, hdr);
2257 
2258 	return -EMSGSIZE;
2259 }
2260 
2261 void tipc_link_set_tolerance(struct tipc_link *l, u32 tol,
2262 			     struct sk_buff_head *xmitq)
2263 {
2264 	l->tolerance = tol;
2265 	if (l->bc_rcvlink)
2266 		l->bc_rcvlink->tolerance = tol;
2267 	if (link_is_up(l))
2268 		tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, tol, 0, xmitq);
2269 }
2270 
2271 void tipc_link_set_prio(struct tipc_link *l, u32 prio,
2272 			struct sk_buff_head *xmitq)
2273 {
2274 	l->priority = prio;
2275 	tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, 0, prio, xmitq);
2276 }
2277 
2278 void tipc_link_set_abort_limit(struct tipc_link *l, u32 limit)
2279 {
2280 	l->abort_limit = limit;
2281 }
2282 
2283 char *tipc_link_name_ext(struct tipc_link *l, char *buf)
2284 {
2285 	if (!l)
2286 		scnprintf(buf, TIPC_MAX_LINK_NAME, "null");
2287 	else if (link_is_bc_sndlink(l))
2288 		scnprintf(buf, TIPC_MAX_LINK_NAME, "broadcast-sender");
2289 	else if (link_is_bc_rcvlink(l))
2290 		scnprintf(buf, TIPC_MAX_LINK_NAME,
2291 			  "broadcast-receiver, peer %x", l->addr);
2292 	else
2293 		memcpy(buf, l->name, TIPC_MAX_LINK_NAME);
2294 
2295 	return buf;
2296 }
2297 
2298 /**
2299  * tipc_link_dump - dump TIPC link data
2300  * @l: tipc link to be dumped
2301  * @dqueues: bitmask to decide if any link queue to be dumped?
2302  *           - TIPC_DUMP_NONE: don't dump link queues
2303  *           - TIPC_DUMP_TRANSMQ: dump link transmq queue
2304  *           - TIPC_DUMP_BACKLOGQ: dump link backlog queue
2305  *           - TIPC_DUMP_DEFERDQ: dump link deferd queue
2306  *           - TIPC_DUMP_INPUTQ: dump link input queue
2307  *           - TIPC_DUMP_WAKEUP: dump link wakeup queue
2308  *           - TIPC_DUMP_ALL: dump all the link queues above
2309  * @buf: returned buffer of dump data in format
2310  */
2311 int tipc_link_dump(struct tipc_link *l, u16 dqueues, char *buf)
2312 {
2313 	int i = 0;
2314 	size_t sz = (dqueues) ? LINK_LMAX : LINK_LMIN;
2315 	struct sk_buff_head *list;
2316 	struct sk_buff *hskb, *tskb;
2317 	u32 len;
2318 
2319 	if (!l) {
2320 		i += scnprintf(buf, sz, "link data: (null)\n");
2321 		return i;
2322 	}
2323 
2324 	i += scnprintf(buf, sz, "link data: %x", l->addr);
2325 	i += scnprintf(buf + i, sz - i, " %x", l->state);
2326 	i += scnprintf(buf + i, sz - i, " %u", l->in_session);
2327 	i += scnprintf(buf + i, sz - i, " %u", l->session);
2328 	i += scnprintf(buf + i, sz - i, " %u", l->peer_session);
2329 	i += scnprintf(buf + i, sz - i, " %u", l->snd_nxt);
2330 	i += scnprintf(buf + i, sz - i, " %u", l->rcv_nxt);
2331 	i += scnprintf(buf + i, sz - i, " %u", l->snd_nxt_state);
2332 	i += scnprintf(buf + i, sz - i, " %u", l->rcv_nxt_state);
2333 	i += scnprintf(buf + i, sz - i, " %x", l->peer_caps);
2334 	i += scnprintf(buf + i, sz - i, " %u", l->silent_intv_cnt);
2335 	i += scnprintf(buf + i, sz - i, " %u", l->rst_cnt);
2336 	i += scnprintf(buf + i, sz - i, " %u", l->prev_from);
2337 	i += scnprintf(buf + i, sz - i, " %u", l->stale_cnt);
2338 	i += scnprintf(buf + i, sz - i, " %u", l->acked);
2339 
2340 	list = &l->transmq;
2341 	len = skb_queue_len(list);
2342 	hskb = skb_peek(list);
2343 	tskb = skb_peek_tail(list);
2344 	i += scnprintf(buf + i, sz - i, " | %u %u %u", len,
2345 		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
2346 		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
2347 
2348 	list = &l->deferdq;
2349 	len = skb_queue_len(list);
2350 	hskb = skb_peek(list);
2351 	tskb = skb_peek_tail(list);
2352 	i += scnprintf(buf + i, sz - i, " | %u %u %u", len,
2353 		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
2354 		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
2355 
2356 	list = &l->backlogq;
2357 	len = skb_queue_len(list);
2358 	hskb = skb_peek(list);
2359 	tskb = skb_peek_tail(list);
2360 	i += scnprintf(buf + i, sz - i, " | %u %u %u", len,
2361 		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
2362 		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
2363 
2364 	list = l->inputq;
2365 	len = skb_queue_len(list);
2366 	hskb = skb_peek(list);
2367 	tskb = skb_peek_tail(list);
2368 	i += scnprintf(buf + i, sz - i, " | %u %u %u\n", len,
2369 		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
2370 		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
2371 
2372 	if (dqueues & TIPC_DUMP_TRANSMQ) {
2373 		i += scnprintf(buf + i, sz - i, "transmq: ");
2374 		i += tipc_list_dump(&l->transmq, false, buf + i);
2375 	}
2376 	if (dqueues & TIPC_DUMP_BACKLOGQ) {
2377 		i += scnprintf(buf + i, sz - i,
2378 			       "backlogq: <%u %u %u %u %u>, ",
2379 			       l->backlog[TIPC_LOW_IMPORTANCE].len,
2380 			       l->backlog[TIPC_MEDIUM_IMPORTANCE].len,
2381 			       l->backlog[TIPC_HIGH_IMPORTANCE].len,
2382 			       l->backlog[TIPC_CRITICAL_IMPORTANCE].len,
2383 			       l->backlog[TIPC_SYSTEM_IMPORTANCE].len);
2384 		i += tipc_list_dump(&l->backlogq, false, buf + i);
2385 	}
2386 	if (dqueues & TIPC_DUMP_DEFERDQ) {
2387 		i += scnprintf(buf + i, sz - i, "deferdq: ");
2388 		i += tipc_list_dump(&l->deferdq, false, buf + i);
2389 	}
2390 	if (dqueues & TIPC_DUMP_INPUTQ) {
2391 		i += scnprintf(buf + i, sz - i, "inputq: ");
2392 		i += tipc_list_dump(l->inputq, false, buf + i);
2393 	}
2394 	if (dqueues & TIPC_DUMP_WAKEUP) {
2395 		i += scnprintf(buf + i, sz - i, "wakeup: ");
2396 		i += tipc_list_dump(&l->wakeupq, false, buf + i);
2397 	}
2398 
2399 	return i;
2400 }
2401