xref: /openbmc/linux/net/tipc/link.c (revision 6c9111bc)
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 #include "crypto.h"
48 
49 #include <linux/pkt_sched.h>
50 
51 struct tipc_stats {
52 	u32 sent_pkts;
53 	u32 recv_pkts;
54 	u32 sent_states;
55 	u32 recv_states;
56 	u32 sent_probes;
57 	u32 recv_probes;
58 	u32 sent_nacks;
59 	u32 recv_nacks;
60 	u32 sent_acks;
61 	u32 sent_bundled;
62 	u32 sent_bundles;
63 	u32 recv_bundled;
64 	u32 recv_bundles;
65 	u32 retransmitted;
66 	u32 sent_fragmented;
67 	u32 sent_fragments;
68 	u32 recv_fragmented;
69 	u32 recv_fragments;
70 	u32 link_congs;		/* # port sends blocked by congestion */
71 	u32 deferred_recv;
72 	u32 duplicates;
73 	u32 max_queue_sz;	/* send queue size high water mark */
74 	u32 accu_queue_sz;	/* used for send queue size profiling */
75 	u32 queue_sz_counts;	/* used for send queue size profiling */
76 	u32 msg_length_counts;	/* used for message length profiling */
77 	u32 msg_lengths_total;	/* used for message length profiling */
78 	u32 msg_length_profile[7]; /* used for msg. length profiling */
79 };
80 
81 /**
82  * struct tipc_link - TIPC link data structure
83  * @addr: network address of link's peer node
84  * @name: link name character string
85  * @media_addr: media address to use when sending messages over link
86  * @timer: link timer
87  * @net: pointer to namespace struct
88  * @refcnt: reference counter for permanent references (owner node & timer)
89  * @peer_session: link session # being used by peer end of link
90  * @peer_bearer_id: bearer id used by link's peer endpoint
91  * @bearer_id: local bearer id used by link
92  * @tolerance: minimum link continuity loss needed to reset link [in ms]
93  * @abort_limit: # of unacknowledged continuity probes needed to reset link
94  * @state: current state of link FSM
95  * @peer_caps: bitmap describing capabilities of peer node
96  * @silent_intv_cnt: # of timer intervals without any reception from peer
97  * @proto_msg: template for control messages generated by link
98  * @pmsg: convenience pointer to "proto_msg" field
99  * @priority: current link priority
100  * @net_plane: current link network plane ('A' through 'H')
101  * @mon_state: cookie with information needed by link monitor
102  * @backlog_limit: backlog queue congestion thresholds (indexed by importance)
103  * @exp_msg_count: # of tunnelled messages expected during link changeover
104  * @reset_rcv_checkpt: seq # of last acknowledged message at time of link reset
105  * @mtu: current maximum packet size for this link
106  * @advertised_mtu: advertised own mtu when link is being established
107  * @transmitq: queue for sent, non-acked messages
108  * @backlogq: queue for messages waiting to be sent
109  * @snt_nxt: next sequence number to use for outbound messages
110  * @ackers: # of peers that needs to ack each packet before it can be released
111  * @acked: # last packet acked by a certain peer. Used for broadcast.
112  * @rcv_nxt: next sequence number to expect for inbound messages
113  * @deferred_queue: deferred queue saved OOS b'cast message received from node
114  * @unacked_window: # of inbound messages rx'd without ack'ing back to peer
115  * @inputq: buffer queue for messages to be delivered upwards
116  * @namedq: buffer queue for name table messages to be delivered upwards
117  * @next_out: ptr to first unsent outbound message in queue
118  * @wakeupq: linked list of wakeup msgs waiting for link congestion to abate
119  * @long_msg_seq_no: next identifier to use for outbound fragmented messages
120  * @reasm_buf: head of partially reassembled inbound message fragments
121  * @bc_rcvr: marks that this is a broadcast receiver link
122  * @stats: collects statistics regarding link activity
123  */
124 struct tipc_link {
125 	u32 addr;
126 	char name[TIPC_MAX_LINK_NAME];
127 	struct net *net;
128 
129 	/* Management and link supervision data */
130 	u16 peer_session;
131 	u16 session;
132 	u16 snd_nxt_state;
133 	u16 rcv_nxt_state;
134 	u32 peer_bearer_id;
135 	u32 bearer_id;
136 	u32 tolerance;
137 	u32 abort_limit;
138 	u32 state;
139 	u16 peer_caps;
140 	bool in_session;
141 	bool active;
142 	u32 silent_intv_cnt;
143 	char if_name[TIPC_MAX_IF_NAME];
144 	u32 priority;
145 	char net_plane;
146 	struct tipc_mon_state mon_state;
147 	u16 rst_cnt;
148 
149 	/* Failover/synch */
150 	u16 drop_point;
151 	struct sk_buff *failover_reasm_skb;
152 	struct sk_buff_head failover_deferdq;
153 
154 	/* Max packet negotiation */
155 	u16 mtu;
156 	u16 advertised_mtu;
157 
158 	/* Sending */
159 	struct sk_buff_head transmq;
160 	struct sk_buff_head backlogq;
161 	struct {
162 		u16 len;
163 		u16 limit;
164 		struct sk_buff *target_bskb;
165 	} backlog[5];
166 	u16 snd_nxt;
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 	u16 window;
178 	u16 min_win;
179 	u16 ssthresh;
180 	u16 max_win;
181 	u16 cong_acks;
182 	u16 checkpoint;
183 
184 	/* Fragmentation/reassembly */
185 	struct sk_buff *reasm_buf;
186 	struct sk_buff *reasm_tnlmsg;
187 
188 	/* Broadcast */
189 	u16 ackers;
190 	u16 acked;
191 	u16 last_gap;
192 	struct tipc_gap_ack_blks *last_ga;
193 	struct tipc_link *bc_rcvlink;
194 	struct tipc_link *bc_sndlink;
195 	u8 nack_state;
196 	bool bc_peer_is_up;
197 
198 	/* Statistics */
199 	struct tipc_stats stats;
200 };
201 
202 /*
203  * Error message prefixes
204  */
205 static const char *link_co_err = "Link tunneling error, ";
206 static const char *link_rst_msg = "Resetting link ";
207 
208 /* Send states for broadcast NACKs
209  */
210 enum {
211 	BC_NACK_SND_CONDITIONAL,
212 	BC_NACK_SND_UNCONDITIONAL,
213 	BC_NACK_SND_SUPPRESS,
214 };
215 
216 #define TIPC_BC_RETR_LIM  (jiffies + msecs_to_jiffies(10))
217 #define TIPC_UC_RETR_TIME (jiffies + msecs_to_jiffies(1))
218 
219 /* Link FSM states:
220  */
221 enum {
222 	LINK_ESTABLISHED     = 0xe,
223 	LINK_ESTABLISHING    = 0xe  << 4,
224 	LINK_RESET           = 0x1  << 8,
225 	LINK_RESETTING       = 0x2  << 12,
226 	LINK_PEER_RESET      = 0xd  << 16,
227 	LINK_FAILINGOVER     = 0xf  << 20,
228 	LINK_SYNCHING        = 0xc  << 24
229 };
230 
231 /* Link FSM state checking routines
232  */
233 static int link_is_up(struct tipc_link *l)
234 {
235 	return l->state & (LINK_ESTABLISHED | LINK_SYNCHING);
236 }
237 
238 static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
239 			       struct sk_buff_head *xmitq);
240 static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
241 				      bool probe_reply, u16 rcvgap,
242 				      int tolerance, int priority,
243 				      struct sk_buff_head *xmitq);
244 static void link_print(struct tipc_link *l, const char *str);
245 static int tipc_link_build_nack_msg(struct tipc_link *l,
246 				    struct sk_buff_head *xmitq);
247 static void tipc_link_build_bc_init_msg(struct tipc_link *l,
248 					struct sk_buff_head *xmitq);
249 static u8 __tipc_build_gap_ack_blks(struct tipc_gap_ack_blks *ga,
250 				    struct tipc_link *l, u8 start_index);
251 static u16 tipc_build_gap_ack_blks(struct tipc_link *l, struct tipc_msg *hdr);
252 static int tipc_link_advance_transmq(struct tipc_link *l, struct tipc_link *r,
253 				     u16 acked, u16 gap,
254 				     struct tipc_gap_ack_blks *ga,
255 				     struct sk_buff_head *xmitq,
256 				     bool *retransmitted, int *rc);
257 static void tipc_link_update_cwin(struct tipc_link *l, int released,
258 				  bool retransmitted);
259 /*
260  *  Simple non-static link routines (i.e. referenced outside this file)
261  */
262 bool tipc_link_is_up(struct tipc_link *l)
263 {
264 	return link_is_up(l);
265 }
266 
267 bool tipc_link_peer_is_down(struct tipc_link *l)
268 {
269 	return l->state == LINK_PEER_RESET;
270 }
271 
272 bool tipc_link_is_reset(struct tipc_link *l)
273 {
274 	return l->state & (LINK_RESET | LINK_FAILINGOVER | LINK_ESTABLISHING);
275 }
276 
277 bool tipc_link_is_establishing(struct tipc_link *l)
278 {
279 	return l->state == LINK_ESTABLISHING;
280 }
281 
282 bool tipc_link_is_synching(struct tipc_link *l)
283 {
284 	return l->state == LINK_SYNCHING;
285 }
286 
287 bool tipc_link_is_failingover(struct tipc_link *l)
288 {
289 	return l->state == LINK_FAILINGOVER;
290 }
291 
292 bool tipc_link_is_blocked(struct tipc_link *l)
293 {
294 	return l->state & (LINK_RESETTING | LINK_PEER_RESET | LINK_FAILINGOVER);
295 }
296 
297 static bool link_is_bc_sndlink(struct tipc_link *l)
298 {
299 	return !l->bc_sndlink;
300 }
301 
302 static bool link_is_bc_rcvlink(struct tipc_link *l)
303 {
304 	return ((l->bc_rcvlink == l) && !link_is_bc_sndlink(l));
305 }
306 
307 void tipc_link_set_active(struct tipc_link *l, bool active)
308 {
309 	l->active = active;
310 }
311 
312 u32 tipc_link_id(struct tipc_link *l)
313 {
314 	return l->peer_bearer_id << 16 | l->bearer_id;
315 }
316 
317 int tipc_link_min_win(struct tipc_link *l)
318 {
319 	return l->min_win;
320 }
321 
322 int tipc_link_max_win(struct tipc_link *l)
323 {
324 	return l->max_win;
325 }
326 
327 int tipc_link_prio(struct tipc_link *l)
328 {
329 	return l->priority;
330 }
331 
332 unsigned long tipc_link_tolerance(struct tipc_link *l)
333 {
334 	return l->tolerance;
335 }
336 
337 struct sk_buff_head *tipc_link_inputq(struct tipc_link *l)
338 {
339 	return l->inputq;
340 }
341 
342 char tipc_link_plane(struct tipc_link *l)
343 {
344 	return l->net_plane;
345 }
346 
347 void tipc_link_update_caps(struct tipc_link *l, u16 capabilities)
348 {
349 	l->peer_caps = capabilities;
350 }
351 
352 void tipc_link_add_bc_peer(struct tipc_link *snd_l,
353 			   struct tipc_link *uc_l,
354 			   struct sk_buff_head *xmitq)
355 {
356 	struct tipc_link *rcv_l = uc_l->bc_rcvlink;
357 
358 	snd_l->ackers++;
359 	rcv_l->acked = snd_l->snd_nxt - 1;
360 	snd_l->state = LINK_ESTABLISHED;
361 	tipc_link_build_bc_init_msg(uc_l, xmitq);
362 }
363 
364 void tipc_link_remove_bc_peer(struct tipc_link *snd_l,
365 			      struct tipc_link *rcv_l,
366 			      struct sk_buff_head *xmitq)
367 {
368 	u16 ack = snd_l->snd_nxt - 1;
369 
370 	snd_l->ackers--;
371 	rcv_l->bc_peer_is_up = true;
372 	rcv_l->state = LINK_ESTABLISHED;
373 	tipc_link_bc_ack_rcv(rcv_l, ack, 0, NULL, xmitq, NULL);
374 	trace_tipc_link_reset(rcv_l, TIPC_DUMP_ALL, "bclink removed!");
375 	tipc_link_reset(rcv_l);
376 	rcv_l->state = LINK_RESET;
377 	if (!snd_l->ackers) {
378 		trace_tipc_link_reset(snd_l, TIPC_DUMP_ALL, "zero ackers!");
379 		tipc_link_reset(snd_l);
380 		snd_l->state = LINK_RESET;
381 		__skb_queue_purge(xmitq);
382 	}
383 }
384 
385 int tipc_link_bc_peers(struct tipc_link *l)
386 {
387 	return l->ackers;
388 }
389 
390 static u16 link_bc_rcv_gap(struct tipc_link *l)
391 {
392 	struct sk_buff *skb = skb_peek(&l->deferdq);
393 	u16 gap = 0;
394 
395 	if (more(l->snd_nxt, l->rcv_nxt))
396 		gap = l->snd_nxt - l->rcv_nxt;
397 	if (skb)
398 		gap = buf_seqno(skb) - l->rcv_nxt;
399 	return gap;
400 }
401 
402 void tipc_link_set_mtu(struct tipc_link *l, int mtu)
403 {
404 	l->mtu = mtu;
405 }
406 
407 int tipc_link_mtu(struct tipc_link *l)
408 {
409 	return l->mtu;
410 }
411 
412 int tipc_link_mss(struct tipc_link *l)
413 {
414 #ifdef CONFIG_TIPC_CRYPTO
415 	return l->mtu - INT_H_SIZE - EMSG_OVERHEAD;
416 #else
417 	return l->mtu - INT_H_SIZE;
418 #endif
419 }
420 
421 u16 tipc_link_rcv_nxt(struct tipc_link *l)
422 {
423 	return l->rcv_nxt;
424 }
425 
426 u16 tipc_link_acked(struct tipc_link *l)
427 {
428 	return l->acked;
429 }
430 
431 char *tipc_link_name(struct tipc_link *l)
432 {
433 	return l->name;
434 }
435 
436 u32 tipc_link_state(struct tipc_link *l)
437 {
438 	return l->state;
439 }
440 
441 /**
442  * tipc_link_create - create a new link
443  * @net: pointer to associated network namespace
444  * @if_name: associated interface name
445  * @bearer_id: id (index) of associated bearer
446  * @tolerance: link tolerance to be used by link
447  * @net_plane: network plane (A,B,c..) this link belongs to
448  * @mtu: mtu to be advertised by link
449  * @priority: priority to be used by link
450  * @min_win: minimal send window to be used by link
451  * @max_win: maximal send window to be used by link
452  * @session: session to be used by link
453  * @ownnode: identity of own node
454  * @peer: node id of peer node
455  * @peer_caps: bitmap describing peer node capabilities
456  * @bc_sndlink: the namespace global link used for broadcast sending
457  * @bc_rcvlink: the peer specific link used for broadcast reception
458  * @inputq: queue to put messages ready for delivery
459  * @namedq: queue to put binding table update messages ready for delivery
460  * @link: return value, pointer to put the created link
461  *
462  * Returns true if link was created, otherwise false
463  */
464 bool tipc_link_create(struct net *net, char *if_name, int bearer_id,
465 		      int tolerance, char net_plane, u32 mtu, int priority,
466 		      u32 min_win, u32 max_win, u32 session, u32 self,
467 		      u32 peer, u8 *peer_id, u16 peer_caps,
468 		      struct tipc_link *bc_sndlink,
469 		      struct tipc_link *bc_rcvlink,
470 		      struct sk_buff_head *inputq,
471 		      struct sk_buff_head *namedq,
472 		      struct tipc_link **link)
473 {
474 	char peer_str[NODE_ID_STR_LEN] = {0,};
475 	char self_str[NODE_ID_STR_LEN] = {0,};
476 	struct tipc_link *l;
477 
478 	l = kzalloc(sizeof(*l), GFP_ATOMIC);
479 	if (!l)
480 		return false;
481 	*link = l;
482 	l->session = session;
483 
484 	/* Set link name for unicast links only */
485 	if (peer_id) {
486 		tipc_nodeid2string(self_str, tipc_own_id(net));
487 		if (strlen(self_str) > 16)
488 			sprintf(self_str, "%x", self);
489 		tipc_nodeid2string(peer_str, peer_id);
490 		if (strlen(peer_str) > 16)
491 			sprintf(peer_str, "%x", peer);
492 	}
493 	/* Peer i/f name will be completed by reset/activate message */
494 	snprintf(l->name, sizeof(l->name), "%s:%s-%s:unknown",
495 		 self_str, if_name, peer_str);
496 
497 	strcpy(l->if_name, if_name);
498 	l->addr = peer;
499 	l->peer_caps = peer_caps;
500 	l->net = net;
501 	l->in_session = false;
502 	l->bearer_id = bearer_id;
503 	l->tolerance = tolerance;
504 	if (bc_rcvlink)
505 		bc_rcvlink->tolerance = tolerance;
506 	l->net_plane = net_plane;
507 	l->advertised_mtu = mtu;
508 	l->mtu = mtu;
509 	l->priority = priority;
510 	tipc_link_set_queue_limits(l, min_win, max_win);
511 	l->ackers = 1;
512 	l->bc_sndlink = bc_sndlink;
513 	l->bc_rcvlink = bc_rcvlink;
514 	l->inputq = inputq;
515 	l->namedq = namedq;
516 	l->state = LINK_RESETTING;
517 	__skb_queue_head_init(&l->transmq);
518 	__skb_queue_head_init(&l->backlogq);
519 	__skb_queue_head_init(&l->deferdq);
520 	__skb_queue_head_init(&l->failover_deferdq);
521 	skb_queue_head_init(&l->wakeupq);
522 	skb_queue_head_init(l->inputq);
523 	return true;
524 }
525 
526 /**
527  * tipc_link_bc_create - create new link to be used for broadcast
528  * @net: pointer to associated network namespace
529  * @mtu: mtu to be used initially if no peers
530  * @min_win: minimal send window to be used by link
531  * @max_win: maximal send window to be used by link
532  * @inputq: queue to put messages ready for delivery
533  * @namedq: queue to put binding table update messages ready for delivery
534  * @link: return value, pointer to put the created link
535  *
536  * Returns true if link was created, otherwise false
537  */
538 bool tipc_link_bc_create(struct net *net, u32 ownnode, u32 peer, u8 *peer_id,
539 			 int mtu, u32 min_win, u32 max_win, u16 peer_caps,
540 			 struct sk_buff_head *inputq,
541 			 struct sk_buff_head *namedq,
542 			 struct tipc_link *bc_sndlink,
543 			 struct tipc_link **link)
544 {
545 	struct tipc_link *l;
546 
547 	if (!tipc_link_create(net, "", MAX_BEARERS, 0, 'Z', mtu, 0, min_win,
548 			      max_win, 0, ownnode, peer, NULL, peer_caps,
549 			      bc_sndlink, NULL, inputq, namedq, link))
550 		return false;
551 
552 	l = *link;
553 	if (peer_id) {
554 		char peer_str[NODE_ID_STR_LEN] = {0,};
555 
556 		tipc_nodeid2string(peer_str, peer_id);
557 		if (strlen(peer_str) > 16)
558 			sprintf(peer_str, "%x", peer);
559 		/* Broadcast receiver link name: "broadcast-link:<peer>" */
560 		snprintf(l->name, sizeof(l->name), "%s:%s", tipc_bclink_name,
561 			 peer_str);
562 	} else {
563 		strcpy(l->name, tipc_bclink_name);
564 	}
565 	trace_tipc_link_reset(l, TIPC_DUMP_ALL, "bclink created!");
566 	tipc_link_reset(l);
567 	l->state = LINK_RESET;
568 	l->ackers = 0;
569 	l->bc_rcvlink = l;
570 
571 	/* Broadcast send link is always up */
572 	if (link_is_bc_sndlink(l))
573 		l->state = LINK_ESTABLISHED;
574 
575 	/* Disable replicast if even a single peer doesn't support it */
576 	if (link_is_bc_rcvlink(l) && !(peer_caps & TIPC_BCAST_RCAST))
577 		tipc_bcast_toggle_rcast(net, false);
578 
579 	return true;
580 }
581 
582 /**
583  * tipc_link_fsm_evt - link finite state machine
584  * @l: pointer to link
585  * @evt: state machine event to be processed
586  */
587 int tipc_link_fsm_evt(struct tipc_link *l, int evt)
588 {
589 	int rc = 0;
590 	int old_state = l->state;
591 
592 	switch (l->state) {
593 	case LINK_RESETTING:
594 		switch (evt) {
595 		case LINK_PEER_RESET_EVT:
596 			l->state = LINK_PEER_RESET;
597 			break;
598 		case LINK_RESET_EVT:
599 			l->state = LINK_RESET;
600 			break;
601 		case LINK_FAILURE_EVT:
602 		case LINK_FAILOVER_BEGIN_EVT:
603 		case LINK_ESTABLISH_EVT:
604 		case LINK_FAILOVER_END_EVT:
605 		case LINK_SYNCH_BEGIN_EVT:
606 		case LINK_SYNCH_END_EVT:
607 		default:
608 			goto illegal_evt;
609 		}
610 		break;
611 	case LINK_RESET:
612 		switch (evt) {
613 		case LINK_PEER_RESET_EVT:
614 			l->state = LINK_ESTABLISHING;
615 			break;
616 		case LINK_FAILOVER_BEGIN_EVT:
617 			l->state = LINK_FAILINGOVER;
618 		case LINK_FAILURE_EVT:
619 		case LINK_RESET_EVT:
620 		case LINK_ESTABLISH_EVT:
621 		case LINK_FAILOVER_END_EVT:
622 			break;
623 		case LINK_SYNCH_BEGIN_EVT:
624 		case LINK_SYNCH_END_EVT:
625 		default:
626 			goto illegal_evt;
627 		}
628 		break;
629 	case LINK_PEER_RESET:
630 		switch (evt) {
631 		case LINK_RESET_EVT:
632 			l->state = LINK_ESTABLISHING;
633 			break;
634 		case LINK_PEER_RESET_EVT:
635 		case LINK_ESTABLISH_EVT:
636 		case LINK_FAILURE_EVT:
637 			break;
638 		case LINK_SYNCH_BEGIN_EVT:
639 		case LINK_SYNCH_END_EVT:
640 		case LINK_FAILOVER_BEGIN_EVT:
641 		case LINK_FAILOVER_END_EVT:
642 		default:
643 			goto illegal_evt;
644 		}
645 		break;
646 	case LINK_FAILINGOVER:
647 		switch (evt) {
648 		case LINK_FAILOVER_END_EVT:
649 			l->state = LINK_RESET;
650 			break;
651 		case LINK_PEER_RESET_EVT:
652 		case LINK_RESET_EVT:
653 		case LINK_ESTABLISH_EVT:
654 		case LINK_FAILURE_EVT:
655 			break;
656 		case LINK_FAILOVER_BEGIN_EVT:
657 		case LINK_SYNCH_BEGIN_EVT:
658 		case LINK_SYNCH_END_EVT:
659 		default:
660 			goto illegal_evt;
661 		}
662 		break;
663 	case LINK_ESTABLISHING:
664 		switch (evt) {
665 		case LINK_ESTABLISH_EVT:
666 			l->state = LINK_ESTABLISHED;
667 			break;
668 		case LINK_FAILOVER_BEGIN_EVT:
669 			l->state = LINK_FAILINGOVER;
670 			break;
671 		case LINK_RESET_EVT:
672 			l->state = LINK_RESET;
673 			break;
674 		case LINK_FAILURE_EVT:
675 		case LINK_PEER_RESET_EVT:
676 		case LINK_SYNCH_BEGIN_EVT:
677 		case LINK_FAILOVER_END_EVT:
678 			break;
679 		case LINK_SYNCH_END_EVT:
680 		default:
681 			goto illegal_evt;
682 		}
683 		break;
684 	case LINK_ESTABLISHED:
685 		switch (evt) {
686 		case LINK_PEER_RESET_EVT:
687 			l->state = LINK_PEER_RESET;
688 			rc |= TIPC_LINK_DOWN_EVT;
689 			break;
690 		case LINK_FAILURE_EVT:
691 			l->state = LINK_RESETTING;
692 			rc |= TIPC_LINK_DOWN_EVT;
693 			break;
694 		case LINK_RESET_EVT:
695 			l->state = LINK_RESET;
696 			break;
697 		case LINK_ESTABLISH_EVT:
698 		case LINK_SYNCH_END_EVT:
699 			break;
700 		case LINK_SYNCH_BEGIN_EVT:
701 			l->state = LINK_SYNCHING;
702 			break;
703 		case LINK_FAILOVER_BEGIN_EVT:
704 		case LINK_FAILOVER_END_EVT:
705 		default:
706 			goto illegal_evt;
707 		}
708 		break;
709 	case LINK_SYNCHING:
710 		switch (evt) {
711 		case LINK_PEER_RESET_EVT:
712 			l->state = LINK_PEER_RESET;
713 			rc |= TIPC_LINK_DOWN_EVT;
714 			break;
715 		case LINK_FAILURE_EVT:
716 			l->state = LINK_RESETTING;
717 			rc |= TIPC_LINK_DOWN_EVT;
718 			break;
719 		case LINK_RESET_EVT:
720 			l->state = LINK_RESET;
721 			break;
722 		case LINK_ESTABLISH_EVT:
723 		case LINK_SYNCH_BEGIN_EVT:
724 			break;
725 		case LINK_SYNCH_END_EVT:
726 			l->state = LINK_ESTABLISHED;
727 			break;
728 		case LINK_FAILOVER_BEGIN_EVT:
729 		case LINK_FAILOVER_END_EVT:
730 		default:
731 			goto illegal_evt;
732 		}
733 		break;
734 	default:
735 		pr_err("Unknown FSM state %x in %s\n", l->state, l->name);
736 	}
737 	trace_tipc_link_fsm(l->name, old_state, l->state, evt);
738 	return rc;
739 illegal_evt:
740 	pr_err("Illegal FSM event %x in state %x on link %s\n",
741 	       evt, l->state, l->name);
742 	trace_tipc_link_fsm(l->name, old_state, l->state, evt);
743 	return rc;
744 }
745 
746 /* link_profile_stats - update statistical profiling of traffic
747  */
748 static void link_profile_stats(struct tipc_link *l)
749 {
750 	struct sk_buff *skb;
751 	struct tipc_msg *msg;
752 	int length;
753 
754 	/* Update counters used in statistical profiling of send traffic */
755 	l->stats.accu_queue_sz += skb_queue_len(&l->transmq);
756 	l->stats.queue_sz_counts++;
757 
758 	skb = skb_peek(&l->transmq);
759 	if (!skb)
760 		return;
761 	msg = buf_msg(skb);
762 	length = msg_size(msg);
763 
764 	if (msg_user(msg) == MSG_FRAGMENTER) {
765 		if (msg_type(msg) != FIRST_FRAGMENT)
766 			return;
767 		length = msg_size(msg_inner_hdr(msg));
768 	}
769 	l->stats.msg_lengths_total += length;
770 	l->stats.msg_length_counts++;
771 	if (length <= 64)
772 		l->stats.msg_length_profile[0]++;
773 	else if (length <= 256)
774 		l->stats.msg_length_profile[1]++;
775 	else if (length <= 1024)
776 		l->stats.msg_length_profile[2]++;
777 	else if (length <= 4096)
778 		l->stats.msg_length_profile[3]++;
779 	else if (length <= 16384)
780 		l->stats.msg_length_profile[4]++;
781 	else if (length <= 32768)
782 		l->stats.msg_length_profile[5]++;
783 	else
784 		l->stats.msg_length_profile[6]++;
785 }
786 
787 /**
788  * tipc_link_too_silent - check if link is "too silent"
789  * @l: tipc link to be checked
790  *
791  * Returns true if the link 'silent_intv_cnt' is about to reach the
792  * 'abort_limit' value, otherwise false
793  */
794 bool tipc_link_too_silent(struct tipc_link *l)
795 {
796 	return (l->silent_intv_cnt + 2 > l->abort_limit);
797 }
798 
799 /* tipc_link_timeout - perform periodic task as instructed from node timeout
800  */
801 int tipc_link_timeout(struct tipc_link *l, struct sk_buff_head *xmitq)
802 {
803 	int mtyp = 0;
804 	int rc = 0;
805 	bool state = false;
806 	bool probe = false;
807 	bool setup = false;
808 	u16 bc_snt = l->bc_sndlink->snd_nxt - 1;
809 	u16 bc_acked = l->bc_rcvlink->acked;
810 	struct tipc_mon_state *mstate = &l->mon_state;
811 
812 	trace_tipc_link_timeout(l, TIPC_DUMP_NONE, " ");
813 	trace_tipc_link_too_silent(l, TIPC_DUMP_ALL, " ");
814 	switch (l->state) {
815 	case LINK_ESTABLISHED:
816 	case LINK_SYNCHING:
817 		mtyp = STATE_MSG;
818 		link_profile_stats(l);
819 		tipc_mon_get_state(l->net, l->addr, mstate, l->bearer_id);
820 		if (mstate->reset || (l->silent_intv_cnt > l->abort_limit))
821 			return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
822 		state = bc_acked != bc_snt;
823 		state |= l->bc_rcvlink->rcv_unacked;
824 		state |= l->rcv_unacked;
825 		state |= !skb_queue_empty(&l->transmq);
826 		probe = mstate->probing;
827 		probe |= l->silent_intv_cnt;
828 		if (probe || mstate->monitoring)
829 			l->silent_intv_cnt++;
830 		probe |= !skb_queue_empty(&l->deferdq);
831 		if (l->snd_nxt == l->checkpoint) {
832 			tipc_link_update_cwin(l, 0, 0);
833 			probe = true;
834 		}
835 		l->checkpoint = l->snd_nxt;
836 		break;
837 	case LINK_RESET:
838 		setup = l->rst_cnt++ <= 4;
839 		setup |= !(l->rst_cnt % 16);
840 		mtyp = RESET_MSG;
841 		break;
842 	case LINK_ESTABLISHING:
843 		setup = true;
844 		mtyp = ACTIVATE_MSG;
845 		break;
846 	case LINK_PEER_RESET:
847 	case LINK_RESETTING:
848 	case LINK_FAILINGOVER:
849 		break;
850 	default:
851 		break;
852 	}
853 
854 	if (state || probe || setup)
855 		tipc_link_build_proto_msg(l, mtyp, probe, 0, 0, 0, 0, xmitq);
856 
857 	return rc;
858 }
859 
860 /**
861  * link_schedule_user - schedule a message sender for wakeup after congestion
862  * @l: congested link
863  * @hdr: header of message that is being sent
864  * Create pseudo msg to send back to user when congestion abates
865  */
866 static int link_schedule_user(struct tipc_link *l, struct tipc_msg *hdr)
867 {
868 	u32 dnode = tipc_own_addr(l->net);
869 	u32 dport = msg_origport(hdr);
870 	struct sk_buff *skb;
871 
872 	/* Create and schedule wakeup pseudo message */
873 	skb = tipc_msg_create(SOCK_WAKEUP, 0, INT_H_SIZE, 0,
874 			      dnode, l->addr, dport, 0, 0);
875 	if (!skb)
876 		return -ENOBUFS;
877 	msg_set_dest_droppable(buf_msg(skb), true);
878 	TIPC_SKB_CB(skb)->chain_imp = msg_importance(hdr);
879 	skb_queue_tail(&l->wakeupq, skb);
880 	l->stats.link_congs++;
881 	trace_tipc_link_conges(l, TIPC_DUMP_ALL, "wakeup scheduled!");
882 	return -ELINKCONG;
883 }
884 
885 /**
886  * link_prepare_wakeup - prepare users for wakeup after congestion
887  * @l: congested link
888  * Wake up a number of waiting users, as permitted by available space
889  * in the send queue
890  */
891 static void link_prepare_wakeup(struct tipc_link *l)
892 {
893 	struct sk_buff_head *wakeupq = &l->wakeupq;
894 	struct sk_buff_head *inputq = l->inputq;
895 	struct sk_buff *skb, *tmp;
896 	struct sk_buff_head tmpq;
897 	int avail[5] = {0,};
898 	int imp = 0;
899 
900 	__skb_queue_head_init(&tmpq);
901 
902 	for (; imp <= TIPC_SYSTEM_IMPORTANCE; imp++)
903 		avail[imp] = l->backlog[imp].limit - l->backlog[imp].len;
904 
905 	skb_queue_walk_safe(wakeupq, skb, tmp) {
906 		imp = TIPC_SKB_CB(skb)->chain_imp;
907 		if (avail[imp] <= 0)
908 			continue;
909 		avail[imp]--;
910 		__skb_unlink(skb, wakeupq);
911 		__skb_queue_tail(&tmpq, skb);
912 	}
913 
914 	spin_lock_bh(&inputq->lock);
915 	skb_queue_splice_tail(&tmpq, inputq);
916 	spin_unlock_bh(&inputq->lock);
917 
918 }
919 
920 /**
921  * tipc_link_set_skb_retransmit_time - set the time at which retransmission of
922  *                                     the given skb should be next attempted
923  * @skb: skb to set a future retransmission time for
924  * @l: link the skb will be transmitted on
925  */
926 static void tipc_link_set_skb_retransmit_time(struct sk_buff *skb,
927 					      struct tipc_link *l)
928 {
929 	if (link_is_bc_sndlink(l))
930 		TIPC_SKB_CB(skb)->nxt_retr = TIPC_BC_RETR_LIM;
931 	else
932 		TIPC_SKB_CB(skb)->nxt_retr = TIPC_UC_RETR_TIME;
933 }
934 
935 void tipc_link_reset(struct tipc_link *l)
936 {
937 	struct sk_buff_head list;
938 	u32 imp;
939 
940 	__skb_queue_head_init(&list);
941 
942 	l->in_session = false;
943 	/* Force re-synch of peer session number before establishing */
944 	l->peer_session--;
945 	l->session++;
946 	l->mtu = l->advertised_mtu;
947 
948 	spin_lock_bh(&l->wakeupq.lock);
949 	skb_queue_splice_init(&l->wakeupq, &list);
950 	spin_unlock_bh(&l->wakeupq.lock);
951 
952 	spin_lock_bh(&l->inputq->lock);
953 	skb_queue_splice_init(&list, l->inputq);
954 	spin_unlock_bh(&l->inputq->lock);
955 
956 	__skb_queue_purge(&l->transmq);
957 	__skb_queue_purge(&l->deferdq);
958 	__skb_queue_purge(&l->backlogq);
959 	__skb_queue_purge(&l->failover_deferdq);
960 	for (imp = 0; imp <= TIPC_SYSTEM_IMPORTANCE; imp++) {
961 		l->backlog[imp].len = 0;
962 		l->backlog[imp].target_bskb = NULL;
963 	}
964 	kfree_skb(l->reasm_buf);
965 	kfree_skb(l->reasm_tnlmsg);
966 	kfree_skb(l->failover_reasm_skb);
967 	l->reasm_buf = NULL;
968 	l->reasm_tnlmsg = NULL;
969 	l->failover_reasm_skb = NULL;
970 	l->rcv_unacked = 0;
971 	l->snd_nxt = 1;
972 	l->rcv_nxt = 1;
973 	l->snd_nxt_state = 1;
974 	l->rcv_nxt_state = 1;
975 	l->acked = 0;
976 	l->last_gap = 0;
977 	kfree(l->last_ga);
978 	l->last_ga = NULL;
979 	l->silent_intv_cnt = 0;
980 	l->rst_cnt = 0;
981 	l->bc_peer_is_up = false;
982 	memset(&l->mon_state, 0, sizeof(l->mon_state));
983 	tipc_link_reset_stats(l);
984 }
985 
986 /**
987  * tipc_link_xmit(): enqueue buffer list according to queue situation
988  * @l: link to use
989  * @list: chain of buffers containing message
990  * @xmitq: returned list of packets to be sent by caller
991  *
992  * Consumes the buffer chain.
993  * Returns 0 if success, or errno: -ELINKCONG, -EMSGSIZE or -ENOBUFS
994  * Messages at TIPC_SYSTEM_IMPORTANCE are always accepted
995  */
996 int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *list,
997 		   struct sk_buff_head *xmitq)
998 {
999 	struct tipc_msg *hdr = buf_msg(skb_peek(list));
1000 	struct sk_buff_head *backlogq = &l->backlogq;
1001 	struct sk_buff_head *transmq = &l->transmq;
1002 	struct sk_buff *skb, *_skb;
1003 	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
1004 	u16 ack = l->rcv_nxt - 1;
1005 	u16 seqno = l->snd_nxt;
1006 	int pkt_cnt = skb_queue_len(list);
1007 	int imp = msg_importance(hdr);
1008 	unsigned int mss = tipc_link_mss(l);
1009 	unsigned int cwin = l->window;
1010 	unsigned int mtu = l->mtu;
1011 	bool new_bundle;
1012 	int rc = 0;
1013 
1014 	if (unlikely(msg_size(hdr) > mtu)) {
1015 		pr_warn("Too large msg, purging xmit list %d %d %d %d %d!\n",
1016 			skb_queue_len(list), msg_user(hdr),
1017 			msg_type(hdr), msg_size(hdr), mtu);
1018 		__skb_queue_purge(list);
1019 		return -EMSGSIZE;
1020 	}
1021 
1022 	/* Allow oversubscription of one data msg per source at congestion */
1023 	if (unlikely(l->backlog[imp].len >= l->backlog[imp].limit)) {
1024 		if (imp == TIPC_SYSTEM_IMPORTANCE) {
1025 			pr_warn("%s<%s>, link overflow", link_rst_msg, l->name);
1026 			return -ENOBUFS;
1027 		}
1028 		rc = link_schedule_user(l, hdr);
1029 	}
1030 
1031 	if (pkt_cnt > 1) {
1032 		l->stats.sent_fragmented++;
1033 		l->stats.sent_fragments += pkt_cnt;
1034 	}
1035 
1036 	/* Prepare each packet for sending, and add to relevant queue: */
1037 	while ((skb = __skb_dequeue(list))) {
1038 		if (likely(skb_queue_len(transmq) < cwin)) {
1039 			hdr = buf_msg(skb);
1040 			msg_set_seqno(hdr, seqno);
1041 			msg_set_ack(hdr, ack);
1042 			msg_set_bcast_ack(hdr, bc_ack);
1043 			_skb = skb_clone(skb, GFP_ATOMIC);
1044 			if (!_skb) {
1045 				kfree_skb(skb);
1046 				__skb_queue_purge(list);
1047 				return -ENOBUFS;
1048 			}
1049 			__skb_queue_tail(transmq, skb);
1050 			tipc_link_set_skb_retransmit_time(skb, l);
1051 			__skb_queue_tail(xmitq, _skb);
1052 			TIPC_SKB_CB(skb)->ackers = l->ackers;
1053 			l->rcv_unacked = 0;
1054 			l->stats.sent_pkts++;
1055 			seqno++;
1056 			continue;
1057 		}
1058 		if (tipc_msg_try_bundle(l->backlog[imp].target_bskb, &skb,
1059 					mss, l->addr, &new_bundle)) {
1060 			if (skb) {
1061 				/* Keep a ref. to the skb for next try */
1062 				l->backlog[imp].target_bskb = skb;
1063 				l->backlog[imp].len++;
1064 				__skb_queue_tail(backlogq, skb);
1065 			} else {
1066 				if (new_bundle) {
1067 					l->stats.sent_bundles++;
1068 					l->stats.sent_bundled++;
1069 				}
1070 				l->stats.sent_bundled++;
1071 			}
1072 			continue;
1073 		}
1074 		l->backlog[imp].target_bskb = NULL;
1075 		l->backlog[imp].len += (1 + skb_queue_len(list));
1076 		__skb_queue_tail(backlogq, skb);
1077 		skb_queue_splice_tail_init(list, backlogq);
1078 	}
1079 	l->snd_nxt = seqno;
1080 	return rc;
1081 }
1082 
1083 static void tipc_link_update_cwin(struct tipc_link *l, int released,
1084 				  bool retransmitted)
1085 {
1086 	int bklog_len = skb_queue_len(&l->backlogq);
1087 	struct sk_buff_head *txq = &l->transmq;
1088 	int txq_len = skb_queue_len(txq);
1089 	u16 cwin = l->window;
1090 
1091 	/* Enter fast recovery */
1092 	if (unlikely(retransmitted)) {
1093 		l->ssthresh = max_t(u16, l->window / 2, 300);
1094 		l->window = min_t(u16, l->ssthresh, l->window);
1095 		return;
1096 	}
1097 	/* Enter slow start */
1098 	if (unlikely(!released)) {
1099 		l->ssthresh = max_t(u16, l->window / 2, 300);
1100 		l->window = l->min_win;
1101 		return;
1102 	}
1103 	/* Don't increase window if no pressure on the transmit queue */
1104 	if (txq_len + bklog_len < cwin)
1105 		return;
1106 
1107 	/* Don't increase window if there are holes the transmit queue */
1108 	if (txq_len && l->snd_nxt - buf_seqno(skb_peek(txq)) != txq_len)
1109 		return;
1110 
1111 	l->cong_acks += released;
1112 
1113 	/* Slow start  */
1114 	if (cwin <= l->ssthresh) {
1115 		l->window = min_t(u16, cwin + released, l->max_win);
1116 		return;
1117 	}
1118 	/* Congestion avoidance */
1119 	if (l->cong_acks < cwin)
1120 		return;
1121 	l->window = min_t(u16, ++cwin, l->max_win);
1122 	l->cong_acks = 0;
1123 }
1124 
1125 static void tipc_link_advance_backlog(struct tipc_link *l,
1126 				      struct sk_buff_head *xmitq)
1127 {
1128 	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
1129 	struct sk_buff_head *txq = &l->transmq;
1130 	struct sk_buff *skb, *_skb;
1131 	u16 ack = l->rcv_nxt - 1;
1132 	u16 seqno = l->snd_nxt;
1133 	struct tipc_msg *hdr;
1134 	u16 cwin = l->window;
1135 	u32 imp;
1136 
1137 	while (skb_queue_len(txq) < cwin) {
1138 		skb = skb_peek(&l->backlogq);
1139 		if (!skb)
1140 			break;
1141 		_skb = skb_clone(skb, GFP_ATOMIC);
1142 		if (!_skb)
1143 			break;
1144 		__skb_dequeue(&l->backlogq);
1145 		hdr = buf_msg(skb);
1146 		imp = msg_importance(hdr);
1147 		l->backlog[imp].len--;
1148 		if (unlikely(skb == l->backlog[imp].target_bskb))
1149 			l->backlog[imp].target_bskb = NULL;
1150 		__skb_queue_tail(&l->transmq, skb);
1151 		tipc_link_set_skb_retransmit_time(skb, l);
1152 
1153 		__skb_queue_tail(xmitq, _skb);
1154 		TIPC_SKB_CB(skb)->ackers = l->ackers;
1155 		msg_set_seqno(hdr, seqno);
1156 		msg_set_ack(hdr, ack);
1157 		msg_set_bcast_ack(hdr, bc_ack);
1158 		l->rcv_unacked = 0;
1159 		l->stats.sent_pkts++;
1160 		seqno++;
1161 	}
1162 	l->snd_nxt = seqno;
1163 }
1164 
1165 /**
1166  * link_retransmit_failure() - Detect repeated retransmit failures
1167  * @l: tipc link sender
1168  * @r: tipc link receiver (= l in case of unicast)
1169  * @rc: returned code
1170  *
1171  * Return: true if the repeated retransmit failures happens, otherwise
1172  * false
1173  */
1174 static bool link_retransmit_failure(struct tipc_link *l, struct tipc_link *r,
1175 				    int *rc)
1176 {
1177 	struct sk_buff *skb = skb_peek(&l->transmq);
1178 	struct tipc_msg *hdr;
1179 
1180 	if (!skb)
1181 		return false;
1182 
1183 	if (!TIPC_SKB_CB(skb)->retr_cnt)
1184 		return false;
1185 
1186 	if (!time_after(jiffies, TIPC_SKB_CB(skb)->retr_stamp +
1187 			msecs_to_jiffies(r->tolerance * 10)))
1188 		return false;
1189 
1190 	hdr = buf_msg(skb);
1191 	if (link_is_bc_sndlink(l) && !less(r->acked, msg_seqno(hdr)))
1192 		return false;
1193 
1194 	pr_warn("Retransmission failure on link <%s>\n", l->name);
1195 	link_print(l, "State of link ");
1196 	pr_info("Failed msg: usr %u, typ %u, len %u, err %u\n",
1197 		msg_user(hdr), msg_type(hdr), msg_size(hdr), msg_errcode(hdr));
1198 	pr_info("sqno %u, prev: %x, dest: %x\n",
1199 		msg_seqno(hdr), msg_prevnode(hdr), msg_destnode(hdr));
1200 	pr_info("retr_stamp %d, retr_cnt %d\n",
1201 		jiffies_to_msecs(TIPC_SKB_CB(skb)->retr_stamp),
1202 		TIPC_SKB_CB(skb)->retr_cnt);
1203 
1204 	trace_tipc_list_dump(&l->transmq, true, "retrans failure!");
1205 	trace_tipc_link_dump(l, TIPC_DUMP_NONE, "retrans failure!");
1206 	trace_tipc_link_dump(r, TIPC_DUMP_NONE, "retrans failure!");
1207 
1208 	if (link_is_bc_sndlink(l)) {
1209 		r->state = LINK_RESET;
1210 		*rc |= TIPC_LINK_DOWN_EVT;
1211 	} else {
1212 		*rc |= tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1213 	}
1214 
1215 	return true;
1216 }
1217 
1218 /* tipc_data_input - deliver data and name distr msgs to upper layer
1219  *
1220  * Consumes buffer if message is of right type
1221  * Node lock must be held
1222  */
1223 static bool tipc_data_input(struct tipc_link *l, struct sk_buff *skb,
1224 			    struct sk_buff_head *inputq)
1225 {
1226 	struct sk_buff_head *mc_inputq = l->bc_rcvlink->inputq;
1227 	struct tipc_msg *hdr = buf_msg(skb);
1228 
1229 	switch (msg_user(hdr)) {
1230 	case TIPC_LOW_IMPORTANCE:
1231 	case TIPC_MEDIUM_IMPORTANCE:
1232 	case TIPC_HIGH_IMPORTANCE:
1233 	case TIPC_CRITICAL_IMPORTANCE:
1234 		if (unlikely(msg_in_group(hdr) || msg_mcast(hdr))) {
1235 			skb_queue_tail(mc_inputq, skb);
1236 			return true;
1237 		}
1238 		fallthrough;
1239 	case CONN_MANAGER:
1240 		skb_queue_tail(inputq, skb);
1241 		return true;
1242 	case GROUP_PROTOCOL:
1243 		skb_queue_tail(mc_inputq, skb);
1244 		return true;
1245 	case NAME_DISTRIBUTOR:
1246 		l->bc_rcvlink->state = LINK_ESTABLISHED;
1247 		skb_queue_tail(l->namedq, skb);
1248 		return true;
1249 	case MSG_BUNDLER:
1250 	case TUNNEL_PROTOCOL:
1251 	case MSG_FRAGMENTER:
1252 	case BCAST_PROTOCOL:
1253 		return false;
1254 #ifdef CONFIG_TIPC_CRYPTO
1255 	case MSG_CRYPTO:
1256 		tipc_crypto_msg_rcv(l->net, skb);
1257 		return true;
1258 #endif
1259 	default:
1260 		pr_warn("Dropping received illegal msg type\n");
1261 		kfree_skb(skb);
1262 		return true;
1263 	};
1264 }
1265 
1266 /* tipc_link_input - process packet that has passed link protocol check
1267  *
1268  * Consumes buffer
1269  */
1270 static int tipc_link_input(struct tipc_link *l, struct sk_buff *skb,
1271 			   struct sk_buff_head *inputq,
1272 			   struct sk_buff **reasm_skb)
1273 {
1274 	struct tipc_msg *hdr = buf_msg(skb);
1275 	struct sk_buff *iskb;
1276 	struct sk_buff_head tmpq;
1277 	int usr = msg_user(hdr);
1278 	int pos = 0;
1279 
1280 	if (usr == MSG_BUNDLER) {
1281 		skb_queue_head_init(&tmpq);
1282 		l->stats.recv_bundles++;
1283 		l->stats.recv_bundled += msg_msgcnt(hdr);
1284 		while (tipc_msg_extract(skb, &iskb, &pos))
1285 			tipc_data_input(l, iskb, &tmpq);
1286 		tipc_skb_queue_splice_tail(&tmpq, inputq);
1287 		return 0;
1288 	} else if (usr == MSG_FRAGMENTER) {
1289 		l->stats.recv_fragments++;
1290 		if (tipc_buf_append(reasm_skb, &skb)) {
1291 			l->stats.recv_fragmented++;
1292 			tipc_data_input(l, skb, inputq);
1293 		} else if (!*reasm_skb && !link_is_bc_rcvlink(l)) {
1294 			pr_warn_ratelimited("Unable to build fragment list\n");
1295 			return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1296 		}
1297 		return 0;
1298 	} else if (usr == BCAST_PROTOCOL) {
1299 		tipc_bcast_lock(l->net);
1300 		tipc_link_bc_init_rcv(l->bc_rcvlink, hdr);
1301 		tipc_bcast_unlock(l->net);
1302 	}
1303 
1304 	kfree_skb(skb);
1305 	return 0;
1306 }
1307 
1308 /* tipc_link_tnl_rcv() - receive TUNNEL_PROTOCOL message, drop or process the
1309  *			 inner message along with the ones in the old link's
1310  *			 deferdq
1311  * @l: tunnel link
1312  * @skb: TUNNEL_PROTOCOL message
1313  * @inputq: queue to put messages ready for delivery
1314  */
1315 static int tipc_link_tnl_rcv(struct tipc_link *l, struct sk_buff *skb,
1316 			     struct sk_buff_head *inputq)
1317 {
1318 	struct sk_buff **reasm_skb = &l->failover_reasm_skb;
1319 	struct sk_buff **reasm_tnlmsg = &l->reasm_tnlmsg;
1320 	struct sk_buff_head *fdefq = &l->failover_deferdq;
1321 	struct tipc_msg *hdr = buf_msg(skb);
1322 	struct sk_buff *iskb;
1323 	int ipos = 0;
1324 	int rc = 0;
1325 	u16 seqno;
1326 
1327 	if (msg_type(hdr) == SYNCH_MSG) {
1328 		kfree_skb(skb);
1329 		return 0;
1330 	}
1331 
1332 	/* Not a fragment? */
1333 	if (likely(!msg_nof_fragms(hdr))) {
1334 		if (unlikely(!tipc_msg_extract(skb, &iskb, &ipos))) {
1335 			pr_warn_ratelimited("Unable to extract msg, defq: %d\n",
1336 					    skb_queue_len(fdefq));
1337 			return 0;
1338 		}
1339 		kfree_skb(skb);
1340 	} else {
1341 		/* Set fragment type for buf_append */
1342 		if (msg_fragm_no(hdr) == 1)
1343 			msg_set_type(hdr, FIRST_FRAGMENT);
1344 		else if (msg_fragm_no(hdr) < msg_nof_fragms(hdr))
1345 			msg_set_type(hdr, FRAGMENT);
1346 		else
1347 			msg_set_type(hdr, LAST_FRAGMENT);
1348 
1349 		if (!tipc_buf_append(reasm_tnlmsg, &skb)) {
1350 			/* Successful but non-complete reassembly? */
1351 			if (*reasm_tnlmsg || link_is_bc_rcvlink(l))
1352 				return 0;
1353 			pr_warn_ratelimited("Unable to reassemble tunnel msg\n");
1354 			return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1355 		}
1356 		iskb = skb;
1357 	}
1358 
1359 	do {
1360 		seqno = buf_seqno(iskb);
1361 		if (unlikely(less(seqno, l->drop_point))) {
1362 			kfree_skb(iskb);
1363 			continue;
1364 		}
1365 		if (unlikely(seqno != l->drop_point)) {
1366 			__tipc_skb_queue_sorted(fdefq, seqno, iskb);
1367 			continue;
1368 		}
1369 
1370 		l->drop_point++;
1371 		if (!tipc_data_input(l, iskb, inputq))
1372 			rc |= tipc_link_input(l, iskb, inputq, reasm_skb);
1373 		if (unlikely(rc))
1374 			break;
1375 	} while ((iskb = __tipc_skb_dequeue(fdefq, l->drop_point)));
1376 
1377 	return rc;
1378 }
1379 
1380 /**
1381  * tipc_get_gap_ack_blks - get Gap ACK blocks from PROTOCOL/STATE_MSG
1382  * @ga: returned pointer to the Gap ACK blocks if any
1383  * @l: the tipc link
1384  * @hdr: the PROTOCOL/STATE_MSG header
1385  * @uc: desired Gap ACK blocks type, i.e. unicast (= 1) or broadcast (= 0)
1386  *
1387  * Return: the total Gap ACK blocks size
1388  */
1389 u16 tipc_get_gap_ack_blks(struct tipc_gap_ack_blks **ga, struct tipc_link *l,
1390 			  struct tipc_msg *hdr, bool uc)
1391 {
1392 	struct tipc_gap_ack_blks *p;
1393 	u16 sz = 0;
1394 
1395 	/* Does peer support the Gap ACK blocks feature? */
1396 	if (l->peer_caps & TIPC_GAP_ACK_BLOCK) {
1397 		p = (struct tipc_gap_ack_blks *)msg_data(hdr);
1398 		sz = ntohs(p->len);
1399 		/* Sanity check */
1400 		if (sz == struct_size(p, gacks, p->ugack_cnt + p->bgack_cnt)) {
1401 			/* Good, check if the desired type exists */
1402 			if ((uc && p->ugack_cnt) || (!uc && p->bgack_cnt))
1403 				goto ok;
1404 		/* Backward compatible: peer might not support bc, but uc? */
1405 		} else if (uc && sz == struct_size(p, gacks, p->ugack_cnt)) {
1406 			if (p->ugack_cnt) {
1407 				p->bgack_cnt = 0;
1408 				goto ok;
1409 			}
1410 		}
1411 	}
1412 	/* Other cases: ignore! */
1413 	p = NULL;
1414 
1415 ok:
1416 	*ga = p;
1417 	return sz;
1418 }
1419 
1420 static u8 __tipc_build_gap_ack_blks(struct tipc_gap_ack_blks *ga,
1421 				    struct tipc_link *l, u8 start_index)
1422 {
1423 	struct tipc_gap_ack *gacks = &ga->gacks[start_index];
1424 	struct sk_buff *skb = skb_peek(&l->deferdq);
1425 	u16 expect, seqno = 0;
1426 	u8 n = 0;
1427 
1428 	if (!skb)
1429 		return 0;
1430 
1431 	expect = buf_seqno(skb);
1432 	skb_queue_walk(&l->deferdq, skb) {
1433 		seqno = buf_seqno(skb);
1434 		if (unlikely(more(seqno, expect))) {
1435 			gacks[n].ack = htons(expect - 1);
1436 			gacks[n].gap = htons(seqno - expect);
1437 			if (++n >= MAX_GAP_ACK_BLKS / 2) {
1438 				pr_info_ratelimited("Gacks on %s: %d, ql: %d!\n",
1439 						    l->name, n,
1440 						    skb_queue_len(&l->deferdq));
1441 				return n;
1442 			}
1443 		} else if (unlikely(less(seqno, expect))) {
1444 			pr_warn("Unexpected skb in deferdq!\n");
1445 			continue;
1446 		}
1447 		expect = seqno + 1;
1448 	}
1449 
1450 	/* last block */
1451 	gacks[n].ack = htons(seqno);
1452 	gacks[n].gap = 0;
1453 	n++;
1454 	return n;
1455 }
1456 
1457 /* tipc_build_gap_ack_blks - build Gap ACK blocks
1458  * @l: tipc unicast link
1459  * @hdr: the tipc message buffer to store the Gap ACK blocks after built
1460  *
1461  * The function builds Gap ACK blocks for both the unicast & broadcast receiver
1462  * links of a certain peer, the buffer after built has the network data format
1463  * as found at the struct tipc_gap_ack_blks definition.
1464  *
1465  * returns the actual allocated memory size
1466  */
1467 static u16 tipc_build_gap_ack_blks(struct tipc_link *l, struct tipc_msg *hdr)
1468 {
1469 	struct tipc_link *bcl = l->bc_rcvlink;
1470 	struct tipc_gap_ack_blks *ga;
1471 	u16 len;
1472 
1473 	ga = (struct tipc_gap_ack_blks *)msg_data(hdr);
1474 
1475 	/* Start with broadcast link first */
1476 	tipc_bcast_lock(bcl->net);
1477 	msg_set_bcast_ack(hdr, bcl->rcv_nxt - 1);
1478 	msg_set_bc_gap(hdr, link_bc_rcv_gap(bcl));
1479 	ga->bgack_cnt = __tipc_build_gap_ack_blks(ga, bcl, 0);
1480 	tipc_bcast_unlock(bcl->net);
1481 
1482 	/* Now for unicast link, but an explicit NACK only (???) */
1483 	ga->ugack_cnt = (msg_seq_gap(hdr)) ?
1484 			__tipc_build_gap_ack_blks(ga, l, ga->bgack_cnt) : 0;
1485 
1486 	/* Total len */
1487 	len = struct_size(ga, gacks, ga->bgack_cnt + ga->ugack_cnt);
1488 	ga->len = htons(len);
1489 	return len;
1490 }
1491 
1492 /* tipc_link_advance_transmq - advance TIPC link transmq queue by releasing
1493  *			       acked packets, also doing retransmissions if
1494  *			       gaps found
1495  * @l: tipc link with transmq queue to be advanced
1496  * @r: tipc link "receiver" i.e. in case of broadcast (= "l" if unicast)
1497  * @acked: seqno of last packet acked by peer without any gaps before
1498  * @gap: # of gap packets
1499  * @ga: buffer pointer to Gap ACK blocks from peer
1500  * @xmitq: queue for accumulating the retransmitted packets if any
1501  * @retransmitted: returned boolean value if a retransmission is really issued
1502  * @rc: returned code e.g. TIPC_LINK_DOWN_EVT if a repeated retransmit failures
1503  *      happens (- unlikely case)
1504  *
1505  * Return: the number of packets released from the link transmq
1506  */
1507 static int tipc_link_advance_transmq(struct tipc_link *l, struct tipc_link *r,
1508 				     u16 acked, u16 gap,
1509 				     struct tipc_gap_ack_blks *ga,
1510 				     struct sk_buff_head *xmitq,
1511 				     bool *retransmitted, int *rc)
1512 {
1513 	struct tipc_gap_ack_blks *last_ga = r->last_ga, *this_ga = NULL;
1514 	struct tipc_gap_ack *gacks = NULL;
1515 	struct sk_buff *skb, *_skb, *tmp;
1516 	struct tipc_msg *hdr;
1517 	u32 qlen = skb_queue_len(&l->transmq);
1518 	u16 nacked = acked, ngap = gap, gack_cnt = 0;
1519 	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
1520 	u16 ack = l->rcv_nxt - 1;
1521 	u16 seqno, n = 0;
1522 	u16 end = r->acked, start = end, offset = r->last_gap;
1523 	u16 si = (last_ga) ? last_ga->start_index : 0;
1524 	bool is_uc = !link_is_bc_sndlink(l);
1525 	bool bc_has_acked = false;
1526 
1527 	trace_tipc_link_retrans(r, acked + 1, acked + gap, &l->transmq);
1528 
1529 	/* Determine Gap ACK blocks if any for the particular link */
1530 	if (ga && is_uc) {
1531 		/* Get the Gap ACKs, uc part */
1532 		gack_cnt = ga->ugack_cnt;
1533 		gacks = &ga->gacks[ga->bgack_cnt];
1534 	} else if (ga) {
1535 		/* Copy the Gap ACKs, bc part, for later renewal if needed */
1536 		this_ga = kmemdup(ga, struct_size(ga, gacks, ga->bgack_cnt),
1537 				  GFP_ATOMIC);
1538 		if (likely(this_ga)) {
1539 			this_ga->start_index = 0;
1540 			/* Start with the bc Gap ACKs */
1541 			gack_cnt = this_ga->bgack_cnt;
1542 			gacks = &this_ga->gacks[0];
1543 		} else {
1544 			/* Hmm, we can get in trouble..., simply ignore it */
1545 			pr_warn_ratelimited("Ignoring bc Gap ACKs, no memory\n");
1546 		}
1547 	}
1548 
1549 	/* Advance the link transmq */
1550 	skb_queue_walk_safe(&l->transmq, skb, tmp) {
1551 		seqno = buf_seqno(skb);
1552 
1553 next_gap_ack:
1554 		if (less_eq(seqno, nacked)) {
1555 			if (is_uc)
1556 				goto release;
1557 			/* Skip packets peer has already acked */
1558 			if (!more(seqno, r->acked))
1559 				continue;
1560 			/* Get the next of last Gap ACK blocks */
1561 			while (more(seqno, end)) {
1562 				if (!last_ga || si >= last_ga->bgack_cnt)
1563 					break;
1564 				start = end + offset + 1;
1565 				end = ntohs(last_ga->gacks[si].ack);
1566 				offset = ntohs(last_ga->gacks[si].gap);
1567 				si++;
1568 				WARN_ONCE(more(start, end) ||
1569 					  (!offset &&
1570 					   si < last_ga->bgack_cnt) ||
1571 					  si > MAX_GAP_ACK_BLKS,
1572 					  "Corrupted Gap ACK: %d %d %d %d %d\n",
1573 					  start, end, offset, si,
1574 					  last_ga->bgack_cnt);
1575 			}
1576 			/* Check against the last Gap ACK block */
1577 			if (in_range(seqno, start, end))
1578 				continue;
1579 			/* Update/release the packet peer is acking */
1580 			bc_has_acked = true;
1581 			if (--TIPC_SKB_CB(skb)->ackers)
1582 				continue;
1583 release:
1584 			/* release skb */
1585 			__skb_unlink(skb, &l->transmq);
1586 			kfree_skb(skb);
1587 		} else if (less_eq(seqno, nacked + ngap)) {
1588 			/* First gap: check if repeated retrans failures? */
1589 			if (unlikely(seqno == acked + 1 &&
1590 				     link_retransmit_failure(l, r, rc))) {
1591 				/* Ignore this bc Gap ACKs if any */
1592 				kfree(this_ga);
1593 				this_ga = NULL;
1594 				break;
1595 			}
1596 			/* retransmit skb if unrestricted*/
1597 			if (time_before(jiffies, TIPC_SKB_CB(skb)->nxt_retr))
1598 				continue;
1599 			tipc_link_set_skb_retransmit_time(skb, l);
1600 			_skb = pskb_copy(skb, GFP_ATOMIC);
1601 			if (!_skb)
1602 				continue;
1603 			hdr = buf_msg(_skb);
1604 			msg_set_ack(hdr, ack);
1605 			msg_set_bcast_ack(hdr, bc_ack);
1606 			_skb->priority = TC_PRIO_CONTROL;
1607 			__skb_queue_tail(xmitq, _skb);
1608 			l->stats.retransmitted++;
1609 			if (!is_uc)
1610 				r->stats.retransmitted++;
1611 			*retransmitted = true;
1612 			/* Increase actual retrans counter & mark first time */
1613 			if (!TIPC_SKB_CB(skb)->retr_cnt++)
1614 				TIPC_SKB_CB(skb)->retr_stamp = jiffies;
1615 		} else {
1616 			/* retry with Gap ACK blocks if any */
1617 			if (n >= gack_cnt)
1618 				break;
1619 			nacked = ntohs(gacks[n].ack);
1620 			ngap = ntohs(gacks[n].gap);
1621 			n++;
1622 			goto next_gap_ack;
1623 		}
1624 	}
1625 
1626 	/* Renew last Gap ACK blocks for bc if needed */
1627 	if (bc_has_acked) {
1628 		if (this_ga) {
1629 			kfree(last_ga);
1630 			r->last_ga = this_ga;
1631 			r->last_gap = gap;
1632 		} else if (last_ga) {
1633 			if (less(acked, start)) {
1634 				si--;
1635 				offset = start - acked - 1;
1636 			} else if (less(acked, end)) {
1637 				acked = end;
1638 			}
1639 			if (si < last_ga->bgack_cnt) {
1640 				last_ga->start_index = si;
1641 				r->last_gap = offset;
1642 			} else {
1643 				kfree(last_ga);
1644 				r->last_ga = NULL;
1645 				r->last_gap = 0;
1646 			}
1647 		} else {
1648 			r->last_gap = 0;
1649 		}
1650 		r->acked = acked;
1651 	} else {
1652 		kfree(this_ga);
1653 	}
1654 
1655 	return qlen - skb_queue_len(&l->transmq);
1656 }
1657 
1658 /* tipc_link_build_state_msg: prepare link state message for transmission
1659  *
1660  * Note that sending of broadcast ack is coordinated among nodes, to reduce
1661  * risk of ack storms towards the sender
1662  */
1663 int tipc_link_build_state_msg(struct tipc_link *l, struct sk_buff_head *xmitq)
1664 {
1665 	if (!l)
1666 		return 0;
1667 
1668 	/* Broadcast ACK must be sent via a unicast link => defer to caller */
1669 	if (link_is_bc_rcvlink(l)) {
1670 		if (((l->rcv_nxt ^ tipc_own_addr(l->net)) & 0xf) != 0xf)
1671 			return 0;
1672 		l->rcv_unacked = 0;
1673 
1674 		/* Use snd_nxt to store peer's snd_nxt in broadcast rcv link */
1675 		l->snd_nxt = l->rcv_nxt;
1676 		return TIPC_LINK_SND_STATE;
1677 	}
1678 	/* Unicast ACK */
1679 	l->rcv_unacked = 0;
1680 	l->stats.sent_acks++;
1681 	tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, 0, 0, xmitq);
1682 	return 0;
1683 }
1684 
1685 /* tipc_link_build_reset_msg: prepare link RESET or ACTIVATE message
1686  */
1687 void tipc_link_build_reset_msg(struct tipc_link *l, struct sk_buff_head *xmitq)
1688 {
1689 	int mtyp = RESET_MSG;
1690 	struct sk_buff *skb;
1691 
1692 	if (l->state == LINK_ESTABLISHING)
1693 		mtyp = ACTIVATE_MSG;
1694 
1695 	tipc_link_build_proto_msg(l, mtyp, 0, 0, 0, 0, 0, xmitq);
1696 
1697 	/* Inform peer that this endpoint is going down if applicable */
1698 	skb = skb_peek_tail(xmitq);
1699 	if (skb && (l->state == LINK_RESET))
1700 		msg_set_peer_stopping(buf_msg(skb), 1);
1701 }
1702 
1703 /* tipc_link_build_nack_msg: prepare link nack message for transmission
1704  * Note that sending of broadcast NACK is coordinated among nodes, to
1705  * reduce the risk of NACK storms towards the sender
1706  */
1707 static int tipc_link_build_nack_msg(struct tipc_link *l,
1708 				    struct sk_buff_head *xmitq)
1709 {
1710 	u32 def_cnt = ++l->stats.deferred_recv;
1711 	struct sk_buff_head *dfq = &l->deferdq;
1712 	u32 defq_len = skb_queue_len(dfq);
1713 	int match1, match2;
1714 
1715 	if (link_is_bc_rcvlink(l)) {
1716 		match1 = def_cnt & 0xf;
1717 		match2 = tipc_own_addr(l->net) & 0xf;
1718 		if (match1 == match2)
1719 			return TIPC_LINK_SND_STATE;
1720 		return 0;
1721 	}
1722 
1723 	if (defq_len >= 3 && !((defq_len - 3) % 16)) {
1724 		u16 rcvgap = buf_seqno(skb_peek(dfq)) - l->rcv_nxt;
1725 
1726 		tipc_link_build_proto_msg(l, STATE_MSG, 0, 0,
1727 					  rcvgap, 0, 0, xmitq);
1728 	}
1729 	return 0;
1730 }
1731 
1732 /* tipc_link_rcv - process TIPC packets/messages arriving from off-node
1733  * @l: the link that should handle the message
1734  * @skb: TIPC packet
1735  * @xmitq: queue to place packets to be sent after this call
1736  */
1737 int tipc_link_rcv(struct tipc_link *l, struct sk_buff *skb,
1738 		  struct sk_buff_head *xmitq)
1739 {
1740 	struct sk_buff_head *defq = &l->deferdq;
1741 	struct tipc_msg *hdr = buf_msg(skb);
1742 	u16 seqno, rcv_nxt, win_lim;
1743 	int released = 0;
1744 	int rc = 0;
1745 
1746 	/* Verify and update link state */
1747 	if (unlikely(msg_user(hdr) == LINK_PROTOCOL))
1748 		return tipc_link_proto_rcv(l, skb, xmitq);
1749 
1750 	/* Don't send probe at next timeout expiration */
1751 	l->silent_intv_cnt = 0;
1752 
1753 	do {
1754 		hdr = buf_msg(skb);
1755 		seqno = msg_seqno(hdr);
1756 		rcv_nxt = l->rcv_nxt;
1757 		win_lim = rcv_nxt + TIPC_MAX_LINK_WIN;
1758 
1759 		if (unlikely(!link_is_up(l))) {
1760 			if (l->state == LINK_ESTABLISHING)
1761 				rc = TIPC_LINK_UP_EVT;
1762 			kfree_skb(skb);
1763 			break;
1764 		}
1765 
1766 		/* Drop if outside receive window */
1767 		if (unlikely(less(seqno, rcv_nxt) || more(seqno, win_lim))) {
1768 			l->stats.duplicates++;
1769 			kfree_skb(skb);
1770 			break;
1771 		}
1772 		released += tipc_link_advance_transmq(l, l, msg_ack(hdr), 0,
1773 						      NULL, NULL, NULL, NULL);
1774 
1775 		/* Defer delivery if sequence gap */
1776 		if (unlikely(seqno != rcv_nxt)) {
1777 			if (!__tipc_skb_queue_sorted(defq, seqno, skb))
1778 				l->stats.duplicates++;
1779 			rc |= tipc_link_build_nack_msg(l, xmitq);
1780 			break;
1781 		}
1782 
1783 		/* Deliver packet */
1784 		l->rcv_nxt++;
1785 		l->stats.recv_pkts++;
1786 
1787 		if (unlikely(msg_user(hdr) == TUNNEL_PROTOCOL))
1788 			rc |= tipc_link_tnl_rcv(l, skb, l->inputq);
1789 		else if (!tipc_data_input(l, skb, l->inputq))
1790 			rc |= tipc_link_input(l, skb, l->inputq, &l->reasm_buf);
1791 		if (unlikely(++l->rcv_unacked >= TIPC_MIN_LINK_WIN))
1792 			rc |= tipc_link_build_state_msg(l, xmitq);
1793 		if (unlikely(rc & ~TIPC_LINK_SND_STATE))
1794 			break;
1795 	} while ((skb = __tipc_skb_dequeue(defq, l->rcv_nxt)));
1796 
1797 	/* Forward queues and wake up waiting users */
1798 	if (released) {
1799 		tipc_link_update_cwin(l, released, 0);
1800 		tipc_link_advance_backlog(l, xmitq);
1801 		if (unlikely(!skb_queue_empty(&l->wakeupq)))
1802 			link_prepare_wakeup(l);
1803 	}
1804 	return rc;
1805 }
1806 
1807 static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
1808 				      bool probe_reply, u16 rcvgap,
1809 				      int tolerance, int priority,
1810 				      struct sk_buff_head *xmitq)
1811 {
1812 	struct tipc_mon_state *mstate = &l->mon_state;
1813 	struct sk_buff_head *dfq = &l->deferdq;
1814 	struct tipc_link *bcl = l->bc_rcvlink;
1815 	struct tipc_msg *hdr;
1816 	struct sk_buff *skb;
1817 	bool node_up = link_is_up(bcl);
1818 	u16 glen = 0, bc_rcvgap = 0;
1819 	int dlen = 0;
1820 	void *data;
1821 
1822 	/* Don't send protocol message during reset or link failover */
1823 	if (tipc_link_is_blocked(l))
1824 		return;
1825 
1826 	if (!tipc_link_is_up(l) && (mtyp == STATE_MSG))
1827 		return;
1828 
1829 	if ((probe || probe_reply) && !skb_queue_empty(dfq))
1830 		rcvgap = buf_seqno(skb_peek(dfq)) - l->rcv_nxt;
1831 
1832 	skb = tipc_msg_create(LINK_PROTOCOL, mtyp, INT_H_SIZE,
1833 			      tipc_max_domain_size + MAX_GAP_ACK_BLKS_SZ,
1834 			      l->addr, tipc_own_addr(l->net), 0, 0, 0);
1835 	if (!skb)
1836 		return;
1837 
1838 	hdr = buf_msg(skb);
1839 	data = msg_data(hdr);
1840 	msg_set_session(hdr, l->session);
1841 	msg_set_bearer_id(hdr, l->bearer_id);
1842 	msg_set_net_plane(hdr, l->net_plane);
1843 	msg_set_next_sent(hdr, l->snd_nxt);
1844 	msg_set_ack(hdr, l->rcv_nxt - 1);
1845 	msg_set_bcast_ack(hdr, bcl->rcv_nxt - 1);
1846 	msg_set_bc_ack_invalid(hdr, !node_up);
1847 	msg_set_last_bcast(hdr, l->bc_sndlink->snd_nxt - 1);
1848 	msg_set_link_tolerance(hdr, tolerance);
1849 	msg_set_linkprio(hdr, priority);
1850 	msg_set_redundant_link(hdr, node_up);
1851 	msg_set_seq_gap(hdr, 0);
1852 	msg_set_seqno(hdr, l->snd_nxt + U16_MAX / 2);
1853 
1854 	if (mtyp == STATE_MSG) {
1855 		if (l->peer_caps & TIPC_LINK_PROTO_SEQNO)
1856 			msg_set_seqno(hdr, l->snd_nxt_state++);
1857 		msg_set_seq_gap(hdr, rcvgap);
1858 		bc_rcvgap = link_bc_rcv_gap(bcl);
1859 		msg_set_bc_gap(hdr, bc_rcvgap);
1860 		msg_set_probe(hdr, probe);
1861 		msg_set_is_keepalive(hdr, probe || probe_reply);
1862 		if (l->peer_caps & TIPC_GAP_ACK_BLOCK)
1863 			glen = tipc_build_gap_ack_blks(l, hdr);
1864 		tipc_mon_prep(l->net, data + glen, &dlen, mstate, l->bearer_id);
1865 		msg_set_size(hdr, INT_H_SIZE + glen + dlen);
1866 		skb_trim(skb, INT_H_SIZE + glen + dlen);
1867 		l->stats.sent_states++;
1868 		l->rcv_unacked = 0;
1869 	} else {
1870 		/* RESET_MSG or ACTIVATE_MSG */
1871 		if (mtyp == ACTIVATE_MSG) {
1872 			msg_set_dest_session_valid(hdr, 1);
1873 			msg_set_dest_session(hdr, l->peer_session);
1874 		}
1875 		msg_set_max_pkt(hdr, l->advertised_mtu);
1876 		strcpy(data, l->if_name);
1877 		msg_set_size(hdr, INT_H_SIZE + TIPC_MAX_IF_NAME);
1878 		skb_trim(skb, INT_H_SIZE + TIPC_MAX_IF_NAME);
1879 	}
1880 	if (probe)
1881 		l->stats.sent_probes++;
1882 	if (rcvgap)
1883 		l->stats.sent_nacks++;
1884 	if (bc_rcvgap)
1885 		bcl->stats.sent_nacks++;
1886 	skb->priority = TC_PRIO_CONTROL;
1887 	__skb_queue_tail(xmitq, skb);
1888 	trace_tipc_proto_build(skb, false, l->name);
1889 }
1890 
1891 void tipc_link_create_dummy_tnl_msg(struct tipc_link *l,
1892 				    struct sk_buff_head *xmitq)
1893 {
1894 	u32 onode = tipc_own_addr(l->net);
1895 	struct tipc_msg *hdr, *ihdr;
1896 	struct sk_buff_head tnlq;
1897 	struct sk_buff *skb;
1898 	u32 dnode = l->addr;
1899 
1900 	__skb_queue_head_init(&tnlq);
1901 	skb = tipc_msg_create(TUNNEL_PROTOCOL, FAILOVER_MSG,
1902 			      INT_H_SIZE, BASIC_H_SIZE,
1903 			      dnode, onode, 0, 0, 0);
1904 	if (!skb) {
1905 		pr_warn("%sunable to create tunnel packet\n", link_co_err);
1906 		return;
1907 	}
1908 
1909 	hdr = buf_msg(skb);
1910 	msg_set_msgcnt(hdr, 1);
1911 	msg_set_bearer_id(hdr, l->peer_bearer_id);
1912 
1913 	ihdr = (struct tipc_msg *)msg_data(hdr);
1914 	tipc_msg_init(onode, ihdr, TIPC_LOW_IMPORTANCE, TIPC_DIRECT_MSG,
1915 		      BASIC_H_SIZE, dnode);
1916 	msg_set_errcode(ihdr, TIPC_ERR_NO_PORT);
1917 	__skb_queue_tail(&tnlq, skb);
1918 	tipc_link_xmit(l, &tnlq, xmitq);
1919 }
1920 
1921 /* tipc_link_tnl_prepare(): prepare and return a list of tunnel packets
1922  * with contents of the link's transmit and backlog queues.
1923  */
1924 void tipc_link_tnl_prepare(struct tipc_link *l, struct tipc_link *tnl,
1925 			   int mtyp, struct sk_buff_head *xmitq)
1926 {
1927 	struct sk_buff_head *fdefq = &tnl->failover_deferdq;
1928 	struct sk_buff *skb, *tnlskb;
1929 	struct tipc_msg *hdr, tnlhdr;
1930 	struct sk_buff_head *queue = &l->transmq;
1931 	struct sk_buff_head tmpxq, tnlq, frags;
1932 	u16 pktlen, pktcnt, seqno = l->snd_nxt;
1933 	bool pktcnt_need_update = false;
1934 	u16 syncpt;
1935 	int rc;
1936 
1937 	if (!tnl)
1938 		return;
1939 
1940 	__skb_queue_head_init(&tnlq);
1941 	/* Link Synching:
1942 	 * From now on, send only one single ("dummy") SYNCH message
1943 	 * to peer. The SYNCH message does not contain any data, just
1944 	 * a header conveying the synch point to the peer.
1945 	 */
1946 	if (mtyp == SYNCH_MSG && (tnl->peer_caps & TIPC_TUNNEL_ENHANCED)) {
1947 		tnlskb = tipc_msg_create(TUNNEL_PROTOCOL, SYNCH_MSG,
1948 					 INT_H_SIZE, 0, l->addr,
1949 					 tipc_own_addr(l->net),
1950 					 0, 0, 0);
1951 		if (!tnlskb) {
1952 			pr_warn("%sunable to create dummy SYNCH_MSG\n",
1953 				link_co_err);
1954 			return;
1955 		}
1956 
1957 		hdr = buf_msg(tnlskb);
1958 		syncpt = l->snd_nxt + skb_queue_len(&l->backlogq) - 1;
1959 		msg_set_syncpt(hdr, syncpt);
1960 		msg_set_bearer_id(hdr, l->peer_bearer_id);
1961 		__skb_queue_tail(&tnlq, tnlskb);
1962 		tipc_link_xmit(tnl, &tnlq, xmitq);
1963 		return;
1964 	}
1965 
1966 	__skb_queue_head_init(&tmpxq);
1967 	__skb_queue_head_init(&frags);
1968 	/* At least one packet required for safe algorithm => add dummy */
1969 	skb = tipc_msg_create(TIPC_LOW_IMPORTANCE, TIPC_DIRECT_MSG,
1970 			      BASIC_H_SIZE, 0, l->addr, tipc_own_addr(l->net),
1971 			      0, 0, TIPC_ERR_NO_PORT);
1972 	if (!skb) {
1973 		pr_warn("%sunable to create tunnel packet\n", link_co_err);
1974 		return;
1975 	}
1976 	__skb_queue_tail(&tnlq, skb);
1977 	tipc_link_xmit(l, &tnlq, &tmpxq);
1978 	__skb_queue_purge(&tmpxq);
1979 
1980 	/* Initialize reusable tunnel packet header */
1981 	tipc_msg_init(tipc_own_addr(l->net), &tnlhdr, TUNNEL_PROTOCOL,
1982 		      mtyp, INT_H_SIZE, l->addr);
1983 	if (mtyp == SYNCH_MSG)
1984 		pktcnt = l->snd_nxt - buf_seqno(skb_peek(&l->transmq));
1985 	else
1986 		pktcnt = skb_queue_len(&l->transmq);
1987 	pktcnt += skb_queue_len(&l->backlogq);
1988 	msg_set_msgcnt(&tnlhdr, pktcnt);
1989 	msg_set_bearer_id(&tnlhdr, l->peer_bearer_id);
1990 tnl:
1991 	/* Wrap each packet into a tunnel packet */
1992 	skb_queue_walk(queue, skb) {
1993 		hdr = buf_msg(skb);
1994 		if (queue == &l->backlogq)
1995 			msg_set_seqno(hdr, seqno++);
1996 		pktlen = msg_size(hdr);
1997 
1998 		/* Tunnel link MTU is not large enough? This could be
1999 		 * due to:
2000 		 * 1) Link MTU has just changed or set differently;
2001 		 * 2) Or FAILOVER on the top of a SYNCH message
2002 		 *
2003 		 * The 2nd case should not happen if peer supports
2004 		 * TIPC_TUNNEL_ENHANCED
2005 		 */
2006 		if (pktlen > tnl->mtu - INT_H_SIZE) {
2007 			if (mtyp == FAILOVER_MSG &&
2008 			    (tnl->peer_caps & TIPC_TUNNEL_ENHANCED)) {
2009 				rc = tipc_msg_fragment(skb, &tnlhdr, tnl->mtu,
2010 						       &frags);
2011 				if (rc) {
2012 					pr_warn("%sunable to frag msg: rc %d\n",
2013 						link_co_err, rc);
2014 					return;
2015 				}
2016 				pktcnt += skb_queue_len(&frags) - 1;
2017 				pktcnt_need_update = true;
2018 				skb_queue_splice_tail_init(&frags, &tnlq);
2019 				continue;
2020 			}
2021 			/* Unluckily, peer doesn't have TIPC_TUNNEL_ENHANCED
2022 			 * => Just warn it and return!
2023 			 */
2024 			pr_warn_ratelimited("%stoo large msg <%d, %d>: %d!\n",
2025 					    link_co_err, msg_user(hdr),
2026 					    msg_type(hdr), msg_size(hdr));
2027 			return;
2028 		}
2029 
2030 		msg_set_size(&tnlhdr, pktlen + INT_H_SIZE);
2031 		tnlskb = tipc_buf_acquire(pktlen + INT_H_SIZE, GFP_ATOMIC);
2032 		if (!tnlskb) {
2033 			pr_warn("%sunable to send packet\n", link_co_err);
2034 			return;
2035 		}
2036 		skb_copy_to_linear_data(tnlskb, &tnlhdr, INT_H_SIZE);
2037 		skb_copy_to_linear_data_offset(tnlskb, INT_H_SIZE, hdr, pktlen);
2038 		__skb_queue_tail(&tnlq, tnlskb);
2039 	}
2040 	if (queue != &l->backlogq) {
2041 		queue = &l->backlogq;
2042 		goto tnl;
2043 	}
2044 
2045 	if (pktcnt_need_update)
2046 		skb_queue_walk(&tnlq, skb) {
2047 			hdr = buf_msg(skb);
2048 			msg_set_msgcnt(hdr, pktcnt);
2049 		}
2050 
2051 	tipc_link_xmit(tnl, &tnlq, xmitq);
2052 
2053 	if (mtyp == FAILOVER_MSG) {
2054 		tnl->drop_point = l->rcv_nxt;
2055 		tnl->failover_reasm_skb = l->reasm_buf;
2056 		l->reasm_buf = NULL;
2057 
2058 		/* Failover the link's deferdq */
2059 		if (unlikely(!skb_queue_empty(fdefq))) {
2060 			pr_warn("Link failover deferdq not empty: %d!\n",
2061 				skb_queue_len(fdefq));
2062 			__skb_queue_purge(fdefq);
2063 		}
2064 		skb_queue_splice_init(&l->deferdq, fdefq);
2065 	}
2066 }
2067 
2068 /**
2069  * tipc_link_failover_prepare() - prepare tnl for link failover
2070  *
2071  * This is a special version of the precursor - tipc_link_tnl_prepare(),
2072  * see the tipc_node_link_failover() for details
2073  *
2074  * @l: failover link
2075  * @tnl: tunnel link
2076  * @xmitq: queue for messages to be xmited
2077  */
2078 void tipc_link_failover_prepare(struct tipc_link *l, struct tipc_link *tnl,
2079 				struct sk_buff_head *xmitq)
2080 {
2081 	struct sk_buff_head *fdefq = &tnl->failover_deferdq;
2082 
2083 	tipc_link_create_dummy_tnl_msg(tnl, xmitq);
2084 
2085 	/* This failover link endpoint was never established before,
2086 	 * so it has not received anything from peer.
2087 	 * Otherwise, it must be a normal failover situation or the
2088 	 * node has entered SELF_DOWN_PEER_LEAVING and both peer nodes
2089 	 * would have to start over from scratch instead.
2090 	 */
2091 	tnl->drop_point = 1;
2092 	tnl->failover_reasm_skb = NULL;
2093 
2094 	/* Initiate the link's failover deferdq */
2095 	if (unlikely(!skb_queue_empty(fdefq))) {
2096 		pr_warn("Link failover deferdq not empty: %d!\n",
2097 			skb_queue_len(fdefq));
2098 		__skb_queue_purge(fdefq);
2099 	}
2100 }
2101 
2102 /* tipc_link_validate_msg(): validate message against current link state
2103  * Returns true if message should be accepted, otherwise false
2104  */
2105 bool tipc_link_validate_msg(struct tipc_link *l, struct tipc_msg *hdr)
2106 {
2107 	u16 curr_session = l->peer_session;
2108 	u16 session = msg_session(hdr);
2109 	int mtyp = msg_type(hdr);
2110 
2111 	if (msg_user(hdr) != LINK_PROTOCOL)
2112 		return true;
2113 
2114 	switch (mtyp) {
2115 	case RESET_MSG:
2116 		if (!l->in_session)
2117 			return true;
2118 		/* Accept only RESET with new session number */
2119 		return more(session, curr_session);
2120 	case ACTIVATE_MSG:
2121 		if (!l->in_session)
2122 			return true;
2123 		/* Accept only ACTIVATE with new or current session number */
2124 		return !less(session, curr_session);
2125 	case STATE_MSG:
2126 		/* Accept only STATE with current session number */
2127 		if (!l->in_session)
2128 			return false;
2129 		if (session != curr_session)
2130 			return false;
2131 		/* Extra sanity check */
2132 		if (!link_is_up(l) && msg_ack(hdr))
2133 			return false;
2134 		if (!(l->peer_caps & TIPC_LINK_PROTO_SEQNO))
2135 			return true;
2136 		/* Accept only STATE with new sequence number */
2137 		return !less(msg_seqno(hdr), l->rcv_nxt_state);
2138 	default:
2139 		return false;
2140 	}
2141 }
2142 
2143 /* tipc_link_proto_rcv(): receive link level protocol message :
2144  * Note that network plane id propagates through the network, and may
2145  * change at any time. The node with lowest numerical id determines
2146  * network plane
2147  */
2148 static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
2149 			       struct sk_buff_head *xmitq)
2150 {
2151 	struct tipc_msg *hdr = buf_msg(skb);
2152 	struct tipc_gap_ack_blks *ga = NULL;
2153 	bool reply = msg_probe(hdr), retransmitted = false;
2154 	u16 dlen = msg_data_sz(hdr), glen = 0;
2155 	u16 peers_snd_nxt =  msg_next_sent(hdr);
2156 	u16 peers_tol = msg_link_tolerance(hdr);
2157 	u16 peers_prio = msg_linkprio(hdr);
2158 	u16 gap = msg_seq_gap(hdr);
2159 	u16 ack = msg_ack(hdr);
2160 	u16 rcv_nxt = l->rcv_nxt;
2161 	u16 rcvgap = 0;
2162 	int mtyp = msg_type(hdr);
2163 	int rc = 0, released;
2164 	char *if_name;
2165 	void *data;
2166 
2167 	trace_tipc_proto_rcv(skb, false, l->name);
2168 	if (tipc_link_is_blocked(l) || !xmitq)
2169 		goto exit;
2170 
2171 	if (tipc_own_addr(l->net) > msg_prevnode(hdr))
2172 		l->net_plane = msg_net_plane(hdr);
2173 
2174 	skb_linearize(skb);
2175 	hdr = buf_msg(skb);
2176 	data = msg_data(hdr);
2177 
2178 	if (!tipc_link_validate_msg(l, hdr)) {
2179 		trace_tipc_skb_dump(skb, false, "PROTO invalid (1)!");
2180 		trace_tipc_link_dump(l, TIPC_DUMP_NONE, "PROTO invalid (1)!");
2181 		goto exit;
2182 	}
2183 
2184 	switch (mtyp) {
2185 	case RESET_MSG:
2186 	case ACTIVATE_MSG:
2187 		/* Complete own link name with peer's interface name */
2188 		if_name =  strrchr(l->name, ':') + 1;
2189 		if (sizeof(l->name) - (if_name - l->name) <= TIPC_MAX_IF_NAME)
2190 			break;
2191 		if (msg_data_sz(hdr) < TIPC_MAX_IF_NAME)
2192 			break;
2193 		strncpy(if_name, data, TIPC_MAX_IF_NAME);
2194 
2195 		/* Update own tolerance if peer indicates a non-zero value */
2196 		if (in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL)) {
2197 			l->tolerance = peers_tol;
2198 			l->bc_rcvlink->tolerance = peers_tol;
2199 		}
2200 		/* Update own priority if peer's priority is higher */
2201 		if (in_range(peers_prio, l->priority + 1, TIPC_MAX_LINK_PRI))
2202 			l->priority = peers_prio;
2203 
2204 		/* If peer is going down we want full re-establish cycle */
2205 		if (msg_peer_stopping(hdr)) {
2206 			rc = tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
2207 			break;
2208 		}
2209 
2210 		/* If this endpoint was re-created while peer was ESTABLISHING
2211 		 * it doesn't know current session number. Force re-synch.
2212 		 */
2213 		if (mtyp == ACTIVATE_MSG && msg_dest_session_valid(hdr) &&
2214 		    l->session != msg_dest_session(hdr)) {
2215 			if (less(l->session, msg_dest_session(hdr)))
2216 				l->session = msg_dest_session(hdr) + 1;
2217 			break;
2218 		}
2219 
2220 		/* ACTIVATE_MSG serves as PEER_RESET if link is already down */
2221 		if (mtyp == RESET_MSG || !link_is_up(l))
2222 			rc = tipc_link_fsm_evt(l, LINK_PEER_RESET_EVT);
2223 
2224 		/* ACTIVATE_MSG takes up link if it was already locally reset */
2225 		if (mtyp == ACTIVATE_MSG && l->state == LINK_ESTABLISHING)
2226 			rc = TIPC_LINK_UP_EVT;
2227 
2228 		l->peer_session = msg_session(hdr);
2229 		l->in_session = true;
2230 		l->peer_bearer_id = msg_bearer_id(hdr);
2231 		if (l->mtu > msg_max_pkt(hdr))
2232 			l->mtu = msg_max_pkt(hdr);
2233 		break;
2234 
2235 	case STATE_MSG:
2236 		l->rcv_nxt_state = msg_seqno(hdr) + 1;
2237 
2238 		/* Update own tolerance if peer indicates a non-zero value */
2239 		if (in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL)) {
2240 			l->tolerance = peers_tol;
2241 			l->bc_rcvlink->tolerance = peers_tol;
2242 		}
2243 		/* Update own prio if peer indicates a different value */
2244 		if ((peers_prio != l->priority) &&
2245 		    in_range(peers_prio, 1, TIPC_MAX_LINK_PRI)) {
2246 			l->priority = peers_prio;
2247 			rc = tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
2248 		}
2249 
2250 		l->silent_intv_cnt = 0;
2251 		l->stats.recv_states++;
2252 		if (msg_probe(hdr))
2253 			l->stats.recv_probes++;
2254 
2255 		if (!link_is_up(l)) {
2256 			if (l->state == LINK_ESTABLISHING)
2257 				rc = TIPC_LINK_UP_EVT;
2258 			break;
2259 		}
2260 
2261 		/* Receive Gap ACK blocks from peer if any */
2262 		glen = tipc_get_gap_ack_blks(&ga, l, hdr, true);
2263 
2264 		tipc_mon_rcv(l->net, data + glen, dlen - glen, l->addr,
2265 			     &l->mon_state, l->bearer_id);
2266 
2267 		/* Send NACK if peer has sent pkts we haven't received yet */
2268 		if ((reply || msg_is_keepalive(hdr)) &&
2269 		    more(peers_snd_nxt, rcv_nxt) &&
2270 		    !tipc_link_is_synching(l) &&
2271 		    skb_queue_empty(&l->deferdq))
2272 			rcvgap = peers_snd_nxt - l->rcv_nxt;
2273 		if (rcvgap || reply)
2274 			tipc_link_build_proto_msg(l, STATE_MSG, 0, reply,
2275 						  rcvgap, 0, 0, xmitq);
2276 
2277 		released = tipc_link_advance_transmq(l, l, ack, gap, ga, xmitq,
2278 						     &retransmitted, &rc);
2279 		if (gap)
2280 			l->stats.recv_nacks++;
2281 		if (released || retransmitted)
2282 			tipc_link_update_cwin(l, released, retransmitted);
2283 		if (released)
2284 			tipc_link_advance_backlog(l, xmitq);
2285 		if (unlikely(!skb_queue_empty(&l->wakeupq)))
2286 			link_prepare_wakeup(l);
2287 	}
2288 exit:
2289 	kfree_skb(skb);
2290 	return rc;
2291 }
2292 
2293 /* tipc_link_build_bc_proto_msg() - create broadcast protocol message
2294  */
2295 static bool tipc_link_build_bc_proto_msg(struct tipc_link *l, bool bcast,
2296 					 u16 peers_snd_nxt,
2297 					 struct sk_buff_head *xmitq)
2298 {
2299 	struct sk_buff *skb;
2300 	struct tipc_msg *hdr;
2301 	struct sk_buff *dfrd_skb = skb_peek(&l->deferdq);
2302 	u16 ack = l->rcv_nxt - 1;
2303 	u16 gap_to = peers_snd_nxt - 1;
2304 
2305 	skb = tipc_msg_create(BCAST_PROTOCOL, STATE_MSG, INT_H_SIZE,
2306 			      0, l->addr, tipc_own_addr(l->net), 0, 0, 0);
2307 	if (!skb)
2308 		return false;
2309 	hdr = buf_msg(skb);
2310 	msg_set_last_bcast(hdr, l->bc_sndlink->snd_nxt - 1);
2311 	msg_set_bcast_ack(hdr, ack);
2312 	msg_set_bcgap_after(hdr, ack);
2313 	if (dfrd_skb)
2314 		gap_to = buf_seqno(dfrd_skb) - 1;
2315 	msg_set_bcgap_to(hdr, gap_to);
2316 	msg_set_non_seq(hdr, bcast);
2317 	__skb_queue_tail(xmitq, skb);
2318 	return true;
2319 }
2320 
2321 /* tipc_link_build_bc_init_msg() - synchronize broadcast link endpoints.
2322  *
2323  * Give a newly added peer node the sequence number where it should
2324  * start receiving and acking broadcast packets.
2325  */
2326 static void tipc_link_build_bc_init_msg(struct tipc_link *l,
2327 					struct sk_buff_head *xmitq)
2328 {
2329 	struct sk_buff_head list;
2330 
2331 	__skb_queue_head_init(&list);
2332 	if (!tipc_link_build_bc_proto_msg(l->bc_rcvlink, false, 0, &list))
2333 		return;
2334 	msg_set_bc_ack_invalid(buf_msg(skb_peek(&list)), true);
2335 	tipc_link_xmit(l, &list, xmitq);
2336 }
2337 
2338 /* tipc_link_bc_init_rcv - receive initial broadcast synch data from peer
2339  */
2340 void tipc_link_bc_init_rcv(struct tipc_link *l, struct tipc_msg *hdr)
2341 {
2342 	int mtyp = msg_type(hdr);
2343 	u16 peers_snd_nxt = msg_bc_snd_nxt(hdr);
2344 
2345 	if (link_is_up(l))
2346 		return;
2347 
2348 	if (msg_user(hdr) == BCAST_PROTOCOL) {
2349 		l->rcv_nxt = peers_snd_nxt;
2350 		l->state = LINK_ESTABLISHED;
2351 		return;
2352 	}
2353 
2354 	if (l->peer_caps & TIPC_BCAST_SYNCH)
2355 		return;
2356 
2357 	if (msg_peer_node_is_up(hdr))
2358 		return;
2359 
2360 	/* Compatibility: accept older, less safe initial synch data */
2361 	if ((mtyp == RESET_MSG) || (mtyp == ACTIVATE_MSG))
2362 		l->rcv_nxt = peers_snd_nxt;
2363 }
2364 
2365 /* tipc_link_bc_sync_rcv - update rcv link according to peer's send state
2366  */
2367 int tipc_link_bc_sync_rcv(struct tipc_link *l, struct tipc_msg *hdr,
2368 			  struct sk_buff_head *xmitq)
2369 {
2370 	u16 peers_snd_nxt = msg_bc_snd_nxt(hdr);
2371 	int rc = 0;
2372 
2373 	if (!link_is_up(l))
2374 		return rc;
2375 
2376 	if (!msg_peer_node_is_up(hdr))
2377 		return rc;
2378 
2379 	/* Open when peer ackowledges our bcast init msg (pkt #1) */
2380 	if (msg_ack(hdr))
2381 		l->bc_peer_is_up = true;
2382 
2383 	if (!l->bc_peer_is_up)
2384 		return rc;
2385 
2386 	/* Ignore if peers_snd_nxt goes beyond receive window */
2387 	if (more(peers_snd_nxt, l->rcv_nxt + l->window))
2388 		return rc;
2389 
2390 	l->snd_nxt = peers_snd_nxt;
2391 	if (link_bc_rcv_gap(l))
2392 		rc |= TIPC_LINK_SND_STATE;
2393 
2394 	/* Return now if sender supports nack via STATE messages */
2395 	if (l->peer_caps & TIPC_BCAST_STATE_NACK)
2396 		return rc;
2397 
2398 	/* Otherwise, be backwards compatible */
2399 
2400 	if (!more(peers_snd_nxt, l->rcv_nxt)) {
2401 		l->nack_state = BC_NACK_SND_CONDITIONAL;
2402 		return 0;
2403 	}
2404 
2405 	/* Don't NACK if one was recently sent or peeked */
2406 	if (l->nack_state == BC_NACK_SND_SUPPRESS) {
2407 		l->nack_state = BC_NACK_SND_UNCONDITIONAL;
2408 		return 0;
2409 	}
2410 
2411 	/* Conditionally delay NACK sending until next synch rcv */
2412 	if (l->nack_state == BC_NACK_SND_CONDITIONAL) {
2413 		l->nack_state = BC_NACK_SND_UNCONDITIONAL;
2414 		if ((peers_snd_nxt - l->rcv_nxt) < TIPC_MIN_LINK_WIN)
2415 			return 0;
2416 	}
2417 
2418 	/* Send NACK now but suppress next one */
2419 	tipc_link_build_bc_proto_msg(l, true, peers_snd_nxt, xmitq);
2420 	l->nack_state = BC_NACK_SND_SUPPRESS;
2421 	return 0;
2422 }
2423 
2424 int tipc_link_bc_ack_rcv(struct tipc_link *r, u16 acked, u16 gap,
2425 			 struct tipc_gap_ack_blks *ga,
2426 			 struct sk_buff_head *xmitq,
2427 			 struct sk_buff_head *retrq)
2428 {
2429 	struct tipc_link *l = r->bc_sndlink;
2430 	bool unused = false;
2431 	int rc = 0;
2432 
2433 	if (!link_is_up(r) || !r->bc_peer_is_up)
2434 		return 0;
2435 
2436 	if (gap) {
2437 		l->stats.recv_nacks++;
2438 		r->stats.recv_nacks++;
2439 	}
2440 
2441 	if (less(acked, r->acked) || (acked == r->acked && !gap && !ga))
2442 		return 0;
2443 
2444 	trace_tipc_link_bc_ack(r, acked, gap, &l->transmq);
2445 	tipc_link_advance_transmq(l, r, acked, gap, ga, retrq, &unused, &rc);
2446 
2447 	tipc_link_advance_backlog(l, xmitq);
2448 	if (unlikely(!skb_queue_empty(&l->wakeupq)))
2449 		link_prepare_wakeup(l);
2450 
2451 	return rc;
2452 }
2453 
2454 /* tipc_link_bc_nack_rcv(): receive broadcast nack message
2455  * This function is here for backwards compatibility, since
2456  * no BCAST_PROTOCOL/STATE messages occur from TIPC v2.5.
2457  */
2458 int tipc_link_bc_nack_rcv(struct tipc_link *l, struct sk_buff *skb,
2459 			  struct sk_buff_head *xmitq)
2460 {
2461 	struct tipc_msg *hdr = buf_msg(skb);
2462 	u32 dnode = msg_destnode(hdr);
2463 	int mtyp = msg_type(hdr);
2464 	u16 acked = msg_bcast_ack(hdr);
2465 	u16 from = acked + 1;
2466 	u16 to = msg_bcgap_to(hdr);
2467 	u16 peers_snd_nxt = to + 1;
2468 	int rc = 0;
2469 
2470 	kfree_skb(skb);
2471 
2472 	if (!tipc_link_is_up(l) || !l->bc_peer_is_up)
2473 		return 0;
2474 
2475 	if (mtyp != STATE_MSG)
2476 		return 0;
2477 
2478 	if (dnode == tipc_own_addr(l->net)) {
2479 		rc = tipc_link_bc_ack_rcv(l, acked, to - acked, NULL, xmitq,
2480 					  xmitq);
2481 		l->stats.recv_nacks++;
2482 		return rc;
2483 	}
2484 
2485 	/* Msg for other node => suppress own NACK at next sync if applicable */
2486 	if (more(peers_snd_nxt, l->rcv_nxt) && !less(l->rcv_nxt, from))
2487 		l->nack_state = BC_NACK_SND_SUPPRESS;
2488 
2489 	return 0;
2490 }
2491 
2492 void tipc_link_set_queue_limits(struct tipc_link *l, u32 min_win, u32 max_win)
2493 {
2494 	int max_bulk = TIPC_MAX_PUBL / (l->mtu / ITEM_SIZE);
2495 
2496 	l->min_win = min_win;
2497 	l->ssthresh = max_win;
2498 	l->max_win = max_win;
2499 	l->window = min_win;
2500 	l->backlog[TIPC_LOW_IMPORTANCE].limit      = min_win * 2;
2501 	l->backlog[TIPC_MEDIUM_IMPORTANCE].limit   = min_win * 4;
2502 	l->backlog[TIPC_HIGH_IMPORTANCE].limit     = min_win * 6;
2503 	l->backlog[TIPC_CRITICAL_IMPORTANCE].limit = min_win * 8;
2504 	l->backlog[TIPC_SYSTEM_IMPORTANCE].limit   = max_bulk;
2505 }
2506 
2507 /**
2508  * link_reset_stats - reset link statistics
2509  * @l: pointer to link
2510  */
2511 void tipc_link_reset_stats(struct tipc_link *l)
2512 {
2513 	memset(&l->stats, 0, sizeof(l->stats));
2514 }
2515 
2516 static void link_print(struct tipc_link *l, const char *str)
2517 {
2518 	struct sk_buff *hskb = skb_peek(&l->transmq);
2519 	u16 head = hskb ? msg_seqno(buf_msg(hskb)) : l->snd_nxt - 1;
2520 	u16 tail = l->snd_nxt - 1;
2521 
2522 	pr_info("%s Link <%s> state %x\n", str, l->name, l->state);
2523 	pr_info("XMTQ: %u [%u-%u], BKLGQ: %u, SNDNX: %u, RCVNX: %u\n",
2524 		skb_queue_len(&l->transmq), head, tail,
2525 		skb_queue_len(&l->backlogq), l->snd_nxt, l->rcv_nxt);
2526 }
2527 
2528 /* Parse and validate nested (link) properties valid for media, bearer and link
2529  */
2530 int tipc_nl_parse_link_prop(struct nlattr *prop, struct nlattr *props[])
2531 {
2532 	int err;
2533 
2534 	err = nla_parse_nested_deprecated(props, TIPC_NLA_PROP_MAX, prop,
2535 					  tipc_nl_prop_policy, NULL);
2536 	if (err)
2537 		return err;
2538 
2539 	if (props[TIPC_NLA_PROP_PRIO]) {
2540 		u32 prio;
2541 
2542 		prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
2543 		if (prio > TIPC_MAX_LINK_PRI)
2544 			return -EINVAL;
2545 	}
2546 
2547 	if (props[TIPC_NLA_PROP_TOL]) {
2548 		u32 tol;
2549 
2550 		tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
2551 		if ((tol < TIPC_MIN_LINK_TOL) || (tol > TIPC_MAX_LINK_TOL))
2552 			return -EINVAL;
2553 	}
2554 
2555 	if (props[TIPC_NLA_PROP_WIN]) {
2556 		u32 max_win;
2557 
2558 		max_win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
2559 		if (max_win < TIPC_DEF_LINK_WIN || max_win > TIPC_MAX_LINK_WIN)
2560 			return -EINVAL;
2561 	}
2562 
2563 	return 0;
2564 }
2565 
2566 static int __tipc_nl_add_stats(struct sk_buff *skb, struct tipc_stats *s)
2567 {
2568 	int i;
2569 	struct nlattr *stats;
2570 
2571 	struct nla_map {
2572 		u32 key;
2573 		u32 val;
2574 	};
2575 
2576 	struct nla_map map[] = {
2577 		{TIPC_NLA_STATS_RX_INFO, 0},
2578 		{TIPC_NLA_STATS_RX_FRAGMENTS, s->recv_fragments},
2579 		{TIPC_NLA_STATS_RX_FRAGMENTED, s->recv_fragmented},
2580 		{TIPC_NLA_STATS_RX_BUNDLES, s->recv_bundles},
2581 		{TIPC_NLA_STATS_RX_BUNDLED, s->recv_bundled},
2582 		{TIPC_NLA_STATS_TX_INFO, 0},
2583 		{TIPC_NLA_STATS_TX_FRAGMENTS, s->sent_fragments},
2584 		{TIPC_NLA_STATS_TX_FRAGMENTED, s->sent_fragmented},
2585 		{TIPC_NLA_STATS_TX_BUNDLES, s->sent_bundles},
2586 		{TIPC_NLA_STATS_TX_BUNDLED, s->sent_bundled},
2587 		{TIPC_NLA_STATS_MSG_PROF_TOT, (s->msg_length_counts) ?
2588 			s->msg_length_counts : 1},
2589 		{TIPC_NLA_STATS_MSG_LEN_CNT, s->msg_length_counts},
2590 		{TIPC_NLA_STATS_MSG_LEN_TOT, s->msg_lengths_total},
2591 		{TIPC_NLA_STATS_MSG_LEN_P0, s->msg_length_profile[0]},
2592 		{TIPC_NLA_STATS_MSG_LEN_P1, s->msg_length_profile[1]},
2593 		{TIPC_NLA_STATS_MSG_LEN_P2, s->msg_length_profile[2]},
2594 		{TIPC_NLA_STATS_MSG_LEN_P3, s->msg_length_profile[3]},
2595 		{TIPC_NLA_STATS_MSG_LEN_P4, s->msg_length_profile[4]},
2596 		{TIPC_NLA_STATS_MSG_LEN_P5, s->msg_length_profile[5]},
2597 		{TIPC_NLA_STATS_MSG_LEN_P6, s->msg_length_profile[6]},
2598 		{TIPC_NLA_STATS_RX_STATES, s->recv_states},
2599 		{TIPC_NLA_STATS_RX_PROBES, s->recv_probes},
2600 		{TIPC_NLA_STATS_RX_NACKS, s->recv_nacks},
2601 		{TIPC_NLA_STATS_RX_DEFERRED, s->deferred_recv},
2602 		{TIPC_NLA_STATS_TX_STATES, s->sent_states},
2603 		{TIPC_NLA_STATS_TX_PROBES, s->sent_probes},
2604 		{TIPC_NLA_STATS_TX_NACKS, s->sent_nacks},
2605 		{TIPC_NLA_STATS_TX_ACKS, s->sent_acks},
2606 		{TIPC_NLA_STATS_RETRANSMITTED, s->retransmitted},
2607 		{TIPC_NLA_STATS_DUPLICATES, s->duplicates},
2608 		{TIPC_NLA_STATS_LINK_CONGS, s->link_congs},
2609 		{TIPC_NLA_STATS_MAX_QUEUE, s->max_queue_sz},
2610 		{TIPC_NLA_STATS_AVG_QUEUE, s->queue_sz_counts ?
2611 			(s->accu_queue_sz / s->queue_sz_counts) : 0}
2612 	};
2613 
2614 	stats = nla_nest_start_noflag(skb, TIPC_NLA_LINK_STATS);
2615 	if (!stats)
2616 		return -EMSGSIZE;
2617 
2618 	for (i = 0; i <  ARRAY_SIZE(map); i++)
2619 		if (nla_put_u32(skb, map[i].key, map[i].val))
2620 			goto msg_full;
2621 
2622 	nla_nest_end(skb, stats);
2623 
2624 	return 0;
2625 msg_full:
2626 	nla_nest_cancel(skb, stats);
2627 
2628 	return -EMSGSIZE;
2629 }
2630 
2631 /* Caller should hold appropriate locks to protect the link */
2632 int __tipc_nl_add_link(struct net *net, struct tipc_nl_msg *msg,
2633 		       struct tipc_link *link, int nlflags)
2634 {
2635 	u32 self = tipc_own_addr(net);
2636 	struct nlattr *attrs;
2637 	struct nlattr *prop;
2638 	void *hdr;
2639 	int err;
2640 
2641 	hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
2642 			  nlflags, TIPC_NL_LINK_GET);
2643 	if (!hdr)
2644 		return -EMSGSIZE;
2645 
2646 	attrs = nla_nest_start_noflag(msg->skb, TIPC_NLA_LINK);
2647 	if (!attrs)
2648 		goto msg_full;
2649 
2650 	if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, link->name))
2651 		goto attr_msg_full;
2652 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_DEST, tipc_cluster_mask(self)))
2653 		goto attr_msg_full;
2654 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_MTU, link->mtu))
2655 		goto attr_msg_full;
2656 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, link->stats.recv_pkts))
2657 		goto attr_msg_full;
2658 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, link->stats.sent_pkts))
2659 		goto attr_msg_full;
2660 
2661 	if (tipc_link_is_up(link))
2662 		if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
2663 			goto attr_msg_full;
2664 	if (link->active)
2665 		if (nla_put_flag(msg->skb, TIPC_NLA_LINK_ACTIVE))
2666 			goto attr_msg_full;
2667 
2668 	prop = nla_nest_start_noflag(msg->skb, TIPC_NLA_LINK_PROP);
2669 	if (!prop)
2670 		goto attr_msg_full;
2671 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
2672 		goto prop_msg_full;
2673 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_TOL, link->tolerance))
2674 		goto prop_msg_full;
2675 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN,
2676 			link->window))
2677 		goto prop_msg_full;
2678 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
2679 		goto prop_msg_full;
2680 	nla_nest_end(msg->skb, prop);
2681 
2682 	err = __tipc_nl_add_stats(msg->skb, &link->stats);
2683 	if (err)
2684 		goto attr_msg_full;
2685 
2686 	nla_nest_end(msg->skb, attrs);
2687 	genlmsg_end(msg->skb, hdr);
2688 
2689 	return 0;
2690 
2691 prop_msg_full:
2692 	nla_nest_cancel(msg->skb, prop);
2693 attr_msg_full:
2694 	nla_nest_cancel(msg->skb, attrs);
2695 msg_full:
2696 	genlmsg_cancel(msg->skb, hdr);
2697 
2698 	return -EMSGSIZE;
2699 }
2700 
2701 static int __tipc_nl_add_bc_link_stat(struct sk_buff *skb,
2702 				      struct tipc_stats *stats)
2703 {
2704 	int i;
2705 	struct nlattr *nest;
2706 
2707 	struct nla_map {
2708 		__u32 key;
2709 		__u32 val;
2710 	};
2711 
2712 	struct nla_map map[] = {
2713 		{TIPC_NLA_STATS_RX_INFO, stats->recv_pkts},
2714 		{TIPC_NLA_STATS_RX_FRAGMENTS, stats->recv_fragments},
2715 		{TIPC_NLA_STATS_RX_FRAGMENTED, stats->recv_fragmented},
2716 		{TIPC_NLA_STATS_RX_BUNDLES, stats->recv_bundles},
2717 		{TIPC_NLA_STATS_RX_BUNDLED, stats->recv_bundled},
2718 		{TIPC_NLA_STATS_TX_INFO, stats->sent_pkts},
2719 		{TIPC_NLA_STATS_TX_FRAGMENTS, stats->sent_fragments},
2720 		{TIPC_NLA_STATS_TX_FRAGMENTED, stats->sent_fragmented},
2721 		{TIPC_NLA_STATS_TX_BUNDLES, stats->sent_bundles},
2722 		{TIPC_NLA_STATS_TX_BUNDLED, stats->sent_bundled},
2723 		{TIPC_NLA_STATS_RX_NACKS, stats->recv_nacks},
2724 		{TIPC_NLA_STATS_RX_DEFERRED, stats->deferred_recv},
2725 		{TIPC_NLA_STATS_TX_NACKS, stats->sent_nacks},
2726 		{TIPC_NLA_STATS_TX_ACKS, stats->sent_acks},
2727 		{TIPC_NLA_STATS_RETRANSMITTED, stats->retransmitted},
2728 		{TIPC_NLA_STATS_DUPLICATES, stats->duplicates},
2729 		{TIPC_NLA_STATS_LINK_CONGS, stats->link_congs},
2730 		{TIPC_NLA_STATS_MAX_QUEUE, stats->max_queue_sz},
2731 		{TIPC_NLA_STATS_AVG_QUEUE, stats->queue_sz_counts ?
2732 			(stats->accu_queue_sz / stats->queue_sz_counts) : 0}
2733 	};
2734 
2735 	nest = nla_nest_start_noflag(skb, TIPC_NLA_LINK_STATS);
2736 	if (!nest)
2737 		return -EMSGSIZE;
2738 
2739 	for (i = 0; i <  ARRAY_SIZE(map); i++)
2740 		if (nla_put_u32(skb, map[i].key, map[i].val))
2741 			goto msg_full;
2742 
2743 	nla_nest_end(skb, nest);
2744 
2745 	return 0;
2746 msg_full:
2747 	nla_nest_cancel(skb, nest);
2748 
2749 	return -EMSGSIZE;
2750 }
2751 
2752 int tipc_nl_add_bc_link(struct net *net, struct tipc_nl_msg *msg,
2753 			struct tipc_link *bcl)
2754 {
2755 	int err;
2756 	void *hdr;
2757 	struct nlattr *attrs;
2758 	struct nlattr *prop;
2759 	u32 bc_mode = tipc_bcast_get_mode(net);
2760 	u32 bc_ratio = tipc_bcast_get_broadcast_ratio(net);
2761 
2762 	if (!bcl)
2763 		return 0;
2764 
2765 	tipc_bcast_lock(net);
2766 
2767 	hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
2768 			  NLM_F_MULTI, TIPC_NL_LINK_GET);
2769 	if (!hdr) {
2770 		tipc_bcast_unlock(net);
2771 		return -EMSGSIZE;
2772 	}
2773 
2774 	attrs = nla_nest_start_noflag(msg->skb, TIPC_NLA_LINK);
2775 	if (!attrs)
2776 		goto msg_full;
2777 
2778 	/* The broadcast link is always up */
2779 	if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
2780 		goto attr_msg_full;
2781 
2782 	if (nla_put_flag(msg->skb, TIPC_NLA_LINK_BROADCAST))
2783 		goto attr_msg_full;
2784 	if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, bcl->name))
2785 		goto attr_msg_full;
2786 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, 0))
2787 		goto attr_msg_full;
2788 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, 0))
2789 		goto attr_msg_full;
2790 
2791 	prop = nla_nest_start_noflag(msg->skb, TIPC_NLA_LINK_PROP);
2792 	if (!prop)
2793 		goto attr_msg_full;
2794 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN, bcl->max_win))
2795 		goto prop_msg_full;
2796 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_BROADCAST, bc_mode))
2797 		goto prop_msg_full;
2798 	if (bc_mode & BCLINK_MODE_SEL)
2799 		if (nla_put_u32(msg->skb, TIPC_NLA_PROP_BROADCAST_RATIO,
2800 				bc_ratio))
2801 			goto prop_msg_full;
2802 	nla_nest_end(msg->skb, prop);
2803 
2804 	err = __tipc_nl_add_bc_link_stat(msg->skb, &bcl->stats);
2805 	if (err)
2806 		goto attr_msg_full;
2807 
2808 	tipc_bcast_unlock(net);
2809 	nla_nest_end(msg->skb, attrs);
2810 	genlmsg_end(msg->skb, hdr);
2811 
2812 	return 0;
2813 
2814 prop_msg_full:
2815 	nla_nest_cancel(msg->skb, prop);
2816 attr_msg_full:
2817 	nla_nest_cancel(msg->skb, attrs);
2818 msg_full:
2819 	tipc_bcast_unlock(net);
2820 	genlmsg_cancel(msg->skb, hdr);
2821 
2822 	return -EMSGSIZE;
2823 }
2824 
2825 void tipc_link_set_tolerance(struct tipc_link *l, u32 tol,
2826 			     struct sk_buff_head *xmitq)
2827 {
2828 	l->tolerance = tol;
2829 	if (l->bc_rcvlink)
2830 		l->bc_rcvlink->tolerance = tol;
2831 	if (link_is_up(l))
2832 		tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, tol, 0, xmitq);
2833 }
2834 
2835 void tipc_link_set_prio(struct tipc_link *l, u32 prio,
2836 			struct sk_buff_head *xmitq)
2837 {
2838 	l->priority = prio;
2839 	tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, 0, prio, xmitq);
2840 }
2841 
2842 void tipc_link_set_abort_limit(struct tipc_link *l, u32 limit)
2843 {
2844 	l->abort_limit = limit;
2845 }
2846 
2847 /**
2848  * tipc_link_dump - dump TIPC link data
2849  * @l: tipc link to be dumped
2850  * @dqueues: bitmask to decide if any link queue to be dumped?
2851  *           - TIPC_DUMP_NONE: don't dump link queues
2852  *           - TIPC_DUMP_TRANSMQ: dump link transmq queue
2853  *           - TIPC_DUMP_BACKLOGQ: dump link backlog queue
2854  *           - TIPC_DUMP_DEFERDQ: dump link deferd queue
2855  *           - TIPC_DUMP_INPUTQ: dump link input queue
2856  *           - TIPC_DUMP_WAKEUP: dump link wakeup queue
2857  *           - TIPC_DUMP_ALL: dump all the link queues above
2858  * @buf: returned buffer of dump data in format
2859  */
2860 int tipc_link_dump(struct tipc_link *l, u16 dqueues, char *buf)
2861 {
2862 	int i = 0;
2863 	size_t sz = (dqueues) ? LINK_LMAX : LINK_LMIN;
2864 	struct sk_buff_head *list;
2865 	struct sk_buff *hskb, *tskb;
2866 	u32 len;
2867 
2868 	if (!l) {
2869 		i += scnprintf(buf, sz, "link data: (null)\n");
2870 		return i;
2871 	}
2872 
2873 	i += scnprintf(buf, sz, "link data: %x", l->addr);
2874 	i += scnprintf(buf + i, sz - i, " %x", l->state);
2875 	i += scnprintf(buf + i, sz - i, " %u", l->in_session);
2876 	i += scnprintf(buf + i, sz - i, " %u", l->session);
2877 	i += scnprintf(buf + i, sz - i, " %u", l->peer_session);
2878 	i += scnprintf(buf + i, sz - i, " %u", l->snd_nxt);
2879 	i += scnprintf(buf + i, sz - i, " %u", l->rcv_nxt);
2880 	i += scnprintf(buf + i, sz - i, " %u", l->snd_nxt_state);
2881 	i += scnprintf(buf + i, sz - i, " %u", l->rcv_nxt_state);
2882 	i += scnprintf(buf + i, sz - i, " %x", l->peer_caps);
2883 	i += scnprintf(buf + i, sz - i, " %u", l->silent_intv_cnt);
2884 	i += scnprintf(buf + i, sz - i, " %u", l->rst_cnt);
2885 	i += scnprintf(buf + i, sz - i, " %u", 0);
2886 	i += scnprintf(buf + i, sz - i, " %u", 0);
2887 	i += scnprintf(buf + i, sz - i, " %u", l->acked);
2888 
2889 	list = &l->transmq;
2890 	len = skb_queue_len(list);
2891 	hskb = skb_peek(list);
2892 	tskb = skb_peek_tail(list);
2893 	i += scnprintf(buf + i, sz - i, " | %u %u %u", len,
2894 		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
2895 		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
2896 
2897 	list = &l->deferdq;
2898 	len = skb_queue_len(list);
2899 	hskb = skb_peek(list);
2900 	tskb = skb_peek_tail(list);
2901 	i += scnprintf(buf + i, sz - i, " | %u %u %u", len,
2902 		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
2903 		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
2904 
2905 	list = &l->backlogq;
2906 	len = skb_queue_len(list);
2907 	hskb = skb_peek(list);
2908 	tskb = skb_peek_tail(list);
2909 	i += scnprintf(buf + i, sz - i, " | %u %u %u", len,
2910 		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
2911 		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
2912 
2913 	list = l->inputq;
2914 	len = skb_queue_len(list);
2915 	hskb = skb_peek(list);
2916 	tskb = skb_peek_tail(list);
2917 	i += scnprintf(buf + i, sz - i, " | %u %u %u\n", len,
2918 		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
2919 		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
2920 
2921 	if (dqueues & TIPC_DUMP_TRANSMQ) {
2922 		i += scnprintf(buf + i, sz - i, "transmq: ");
2923 		i += tipc_list_dump(&l->transmq, false, buf + i);
2924 	}
2925 	if (dqueues & TIPC_DUMP_BACKLOGQ) {
2926 		i += scnprintf(buf + i, sz - i,
2927 			       "backlogq: <%u %u %u %u %u>, ",
2928 			       l->backlog[TIPC_LOW_IMPORTANCE].len,
2929 			       l->backlog[TIPC_MEDIUM_IMPORTANCE].len,
2930 			       l->backlog[TIPC_HIGH_IMPORTANCE].len,
2931 			       l->backlog[TIPC_CRITICAL_IMPORTANCE].len,
2932 			       l->backlog[TIPC_SYSTEM_IMPORTANCE].len);
2933 		i += tipc_list_dump(&l->backlogq, false, buf + i);
2934 	}
2935 	if (dqueues & TIPC_DUMP_DEFERDQ) {
2936 		i += scnprintf(buf + i, sz - i, "deferdq: ");
2937 		i += tipc_list_dump(&l->deferdq, false, buf + i);
2938 	}
2939 	if (dqueues & TIPC_DUMP_INPUTQ) {
2940 		i += scnprintf(buf + i, sz - i, "inputq: ");
2941 		i += tipc_list_dump(l->inputq, false, buf + i);
2942 	}
2943 	if (dqueues & TIPC_DUMP_WAKEUP) {
2944 		i += scnprintf(buf + i, sz - i, "wakeup: ");
2945 		i += tipc_list_dump(&l->wakeupq, false, buf + i);
2946 	}
2947 
2948 	return i;
2949 }
2950