xref: /linux/net/tipc/link.c (revision 4e9903b0861c9df3464b82db4a7025863bac1897)
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  * @net: pointer to namespace struct
86  * @peer_session: link session # being used by peer end of link
87  * @peer_bearer_id: bearer id used by link's peer endpoint
88  * @bearer_id: local bearer id used by link
89  * @tolerance: minimum link continuity loss needed to reset link [in ms]
90  * @abort_limit: # of unacknowledged continuity probes needed to reset link
91  * @state: current state of link FSM
92  * @peer_caps: bitmap describing capabilities of peer node
93  * @silent_intv_cnt: # of timer intervals without any reception from peer
94  * @priority: current link priority
95  * @net_plane: current link network plane ('A' through 'H')
96  * @mon_state: cookie with information needed by link monitor
97  * @mtu: current maximum packet size for this link
98  * @advertised_mtu: advertised own mtu when link is being established
99  * @backlogq: queue for messages waiting to be sent
100  * @ackers: # of peers that needs to ack each packet before it can be released
101  * @acked: # last packet acked by a certain peer. Used for broadcast.
102  * @rcv_nxt: next sequence number to expect for inbound messages
103  * @inputq: buffer queue for messages to be delivered upwards
104  * @namedq: buffer queue for name table messages to be delivered upwards
105  * @wakeupq: linked list of wakeup msgs waiting for link congestion to abate
106  * @reasm_buf: head of partially reassembled inbound message fragments
107  * @stats: collects statistics regarding link activity
108  * @session: session to be used by link
109  * @snd_nxt_state: next send seq number
110  * @rcv_nxt_state: next rcv seq number
111  * @in_session: have received ACTIVATE_MSG from peer
112  * @active: link is active
113  * @if_name: associated interface name
114  * @rst_cnt: link reset counter
115  * @drop_point: seq number for failover handling (FIXME)
116  * @failover_reasm_skb: saved failover msg ptr (FIXME)
117  * @failover_deferdq: deferred message queue for failover processing (FIXME)
118  * @transmq: the link's transmit queue
119  * @backlog: link's backlog by priority (importance)
120  * @snd_nxt: next sequence number to be used
121  * @rcv_unacked: # messages read by user, but not yet acked back to peer
122  * @deferdq: deferred receive queue
123  * @window: sliding window size for congestion handling
124  * @min_win: minimal send window to be used by link
125  * @ssthresh: slow start threshold for congestion handling
126  * @max_win: maximal send window to be used by link
127  * @cong_acks: congestion acks for congestion avoidance (FIXME)
128  * @checkpoint: seq number for congestion window size handling
129  * @reasm_tnlmsg: fragmentation/reassembly area for tunnel protocol message
130  * @last_gap: last gap ack blocks for bcast (FIXME)
131  * @last_ga: ptr to gap ack blocks
132  * @bc_rcvlink: the peer specific link used for broadcast reception
133  * @bc_sndlink: the namespace global link used for broadcast sending
134  * @nack_state: bcast nack state
135  * @bc_peer_is_up: peer has acked the bcast init msg
136  */
137 struct tipc_link {
138 	u32 addr;
139 	char name[TIPC_MAX_LINK_NAME];
140 	struct net *net;
141 
142 	/* Management and link supervision data */
143 	u16 peer_session;
144 	u16 session;
145 	u16 snd_nxt_state;
146 	u16 rcv_nxt_state;
147 	u32 peer_bearer_id;
148 	u32 bearer_id;
149 	u32 tolerance;
150 	u32 abort_limit;
151 	u32 state;
152 	u16 peer_caps;
153 	bool in_session;
154 	bool active;
155 	u32 silent_intv_cnt;
156 	char if_name[TIPC_MAX_IF_NAME];
157 	u32 priority;
158 	char net_plane;
159 	struct tipc_mon_state mon_state;
160 	u16 rst_cnt;
161 
162 	/* Failover/synch */
163 	u16 drop_point;
164 	struct sk_buff *failover_reasm_skb;
165 	struct sk_buff_head failover_deferdq;
166 
167 	/* Max packet negotiation */
168 	u16 mtu;
169 	u16 advertised_mtu;
170 
171 	/* Sending */
172 	struct sk_buff_head transmq;
173 	struct sk_buff_head backlogq;
174 	struct {
175 		u16 len;
176 		u16 limit;
177 		struct sk_buff *target_bskb;
178 	} backlog[5];
179 	u16 snd_nxt;
180 
181 	/* Reception */
182 	u16 rcv_nxt;
183 	u32 rcv_unacked;
184 	struct sk_buff_head deferdq;
185 	struct sk_buff_head *inputq;
186 	struct sk_buff_head *namedq;
187 
188 	/* Congestion handling */
189 	struct sk_buff_head wakeupq;
190 	u16 window;
191 	u16 min_win;
192 	u16 ssthresh;
193 	u16 max_win;
194 	u16 cong_acks;
195 	u16 checkpoint;
196 
197 	/* Fragmentation/reassembly */
198 	struct sk_buff *reasm_buf;
199 	struct sk_buff *reasm_tnlmsg;
200 
201 	/* Broadcast */
202 	u16 ackers;
203 	u16 acked;
204 	u16 last_gap;
205 	struct tipc_gap_ack_blks *last_ga;
206 	struct tipc_link *bc_rcvlink;
207 	struct tipc_link *bc_sndlink;
208 	u8 nack_state;
209 	bool bc_peer_is_up;
210 
211 	/* Statistics */
212 	struct tipc_stats stats;
213 };
214 
215 /*
216  * Error message prefixes
217  */
218 static const char *link_co_err = "Link tunneling error, ";
219 static const char *link_rst_msg = "Resetting link ";
220 
221 /* Send states for broadcast NACKs
222  */
223 enum {
224 	BC_NACK_SND_CONDITIONAL,
225 	BC_NACK_SND_UNCONDITIONAL,
226 	BC_NACK_SND_SUPPRESS,
227 };
228 
229 #define TIPC_BC_RETR_LIM  (jiffies + msecs_to_jiffies(10))
230 #define TIPC_UC_RETR_TIME (jiffies + msecs_to_jiffies(1))
231 
232 /* Link FSM states:
233  */
234 enum {
235 	LINK_ESTABLISHED     = 0xe,
236 	LINK_ESTABLISHING    = 0xe  << 4,
237 	LINK_RESET           = 0x1  << 8,
238 	LINK_RESETTING       = 0x2  << 12,
239 	LINK_PEER_RESET      = 0xd  << 16,
240 	LINK_FAILINGOVER     = 0xf  << 20,
241 	LINK_SYNCHING        = 0xc  << 24
242 };
243 
244 static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
245 			       struct sk_buff_head *xmitq);
246 static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
247 				      bool probe_reply, u16 rcvgap,
248 				      int tolerance, int priority,
249 				      struct sk_buff_head *xmitq);
250 static void link_print(struct tipc_link *l, const char *str);
251 static int tipc_link_build_nack_msg(struct tipc_link *l,
252 				    struct sk_buff_head *xmitq);
253 static void tipc_link_build_bc_init_msg(struct tipc_link *l,
254 					struct sk_buff_head *xmitq);
255 static u8 __tipc_build_gap_ack_blks(struct tipc_gap_ack_blks *ga,
256 				    struct tipc_link *l, u8 start_index);
257 static u16 tipc_build_gap_ack_blks(struct tipc_link *l, struct tipc_msg *hdr);
258 static int tipc_link_advance_transmq(struct tipc_link *l, struct tipc_link *r,
259 				     u16 acked, u16 gap,
260 				     struct tipc_gap_ack_blks *ga,
261 				     struct sk_buff_head *xmitq,
262 				     bool *retransmitted, int *rc);
263 static void tipc_link_update_cwin(struct tipc_link *l, int released,
264 				  bool retransmitted);
265 /*
266  *  Simple non-static link routines (i.e. referenced outside this file)
267  */
268 bool tipc_link_is_up(struct tipc_link *l)
269 {
270 	return l->state & (LINK_ESTABLISHED | LINK_SYNCHING);
271 }
272 
273 bool tipc_link_peer_is_down(struct tipc_link *l)
274 {
275 	return l->state == LINK_PEER_RESET;
276 }
277 
278 bool tipc_link_is_reset(struct tipc_link *l)
279 {
280 	return l->state & (LINK_RESET | LINK_FAILINGOVER | LINK_ESTABLISHING);
281 }
282 
283 bool tipc_link_is_establishing(struct tipc_link *l)
284 {
285 	return l->state == LINK_ESTABLISHING;
286 }
287 
288 bool tipc_link_is_synching(struct tipc_link *l)
289 {
290 	return l->state == LINK_SYNCHING;
291 }
292 
293 bool tipc_link_is_failingover(struct tipc_link *l)
294 {
295 	return l->state == LINK_FAILINGOVER;
296 }
297 
298 bool tipc_link_is_blocked(struct tipc_link *l)
299 {
300 	return l->state & (LINK_RESETTING | LINK_PEER_RESET | LINK_FAILINGOVER);
301 }
302 
303 static bool link_is_bc_sndlink(struct tipc_link *l)
304 {
305 	return !l->bc_sndlink;
306 }
307 
308 static bool link_is_bc_rcvlink(struct tipc_link *l)
309 {
310 	return ((l->bc_rcvlink == l) && !link_is_bc_sndlink(l));
311 }
312 
313 void tipc_link_set_active(struct tipc_link *l, bool active)
314 {
315 	l->active = active;
316 }
317 
318 u32 tipc_link_id(struct tipc_link *l)
319 {
320 	return l->peer_bearer_id << 16 | l->bearer_id;
321 }
322 
323 int tipc_link_min_win(struct tipc_link *l)
324 {
325 	return l->min_win;
326 }
327 
328 int tipc_link_max_win(struct tipc_link *l)
329 {
330 	return l->max_win;
331 }
332 
333 int tipc_link_prio(struct tipc_link *l)
334 {
335 	return l->priority;
336 }
337 
338 unsigned long tipc_link_tolerance(struct tipc_link *l)
339 {
340 	return l->tolerance;
341 }
342 
343 struct sk_buff_head *tipc_link_inputq(struct tipc_link *l)
344 {
345 	return l->inputq;
346 }
347 
348 char tipc_link_plane(struct tipc_link *l)
349 {
350 	return l->net_plane;
351 }
352 
353 struct net *tipc_link_net(struct tipc_link *l)
354 {
355 	return l->net;
356 }
357 
358 void tipc_link_update_caps(struct tipc_link *l, u16 capabilities)
359 {
360 	l->peer_caps = capabilities;
361 }
362 
363 void tipc_link_add_bc_peer(struct tipc_link *snd_l,
364 			   struct tipc_link *uc_l,
365 			   struct sk_buff_head *xmitq)
366 {
367 	struct tipc_link *rcv_l = uc_l->bc_rcvlink;
368 
369 	snd_l->ackers++;
370 	rcv_l->acked = snd_l->snd_nxt - 1;
371 	snd_l->state = LINK_ESTABLISHED;
372 	tipc_link_build_bc_init_msg(uc_l, xmitq);
373 }
374 
375 void tipc_link_remove_bc_peer(struct tipc_link *snd_l,
376 			      struct tipc_link *rcv_l,
377 			      struct sk_buff_head *xmitq)
378 {
379 	u16 ack = snd_l->snd_nxt - 1;
380 
381 	snd_l->ackers--;
382 	rcv_l->bc_peer_is_up = true;
383 	rcv_l->state = LINK_ESTABLISHED;
384 	tipc_link_bc_ack_rcv(rcv_l, ack, 0, NULL, xmitq, NULL);
385 	trace_tipc_link_reset(rcv_l, TIPC_DUMP_ALL, "bclink removed!");
386 	tipc_link_reset(rcv_l);
387 	rcv_l->state = LINK_RESET;
388 	if (!snd_l->ackers) {
389 		trace_tipc_link_reset(snd_l, TIPC_DUMP_ALL, "zero ackers!");
390 		tipc_link_reset(snd_l);
391 		snd_l->state = LINK_RESET;
392 		__skb_queue_purge(xmitq);
393 	}
394 }
395 
396 int tipc_link_bc_peers(struct tipc_link *l)
397 {
398 	return l->ackers;
399 }
400 
401 static u16 link_bc_rcv_gap(struct tipc_link *l)
402 {
403 	struct sk_buff *skb = skb_peek(&l->deferdq);
404 	u16 gap = 0;
405 
406 	if (more(l->snd_nxt, l->rcv_nxt))
407 		gap = l->snd_nxt - l->rcv_nxt;
408 	if (skb)
409 		gap = buf_seqno(skb) - l->rcv_nxt;
410 	return gap;
411 }
412 
413 void tipc_link_set_mtu(struct tipc_link *l, int mtu)
414 {
415 	l->mtu = mtu;
416 }
417 
418 int tipc_link_mtu(struct tipc_link *l)
419 {
420 	return l->mtu;
421 }
422 
423 int tipc_link_mss(struct tipc_link *l)
424 {
425 #ifdef CONFIG_TIPC_CRYPTO
426 	return l->mtu - INT_H_SIZE - EMSG_OVERHEAD;
427 #else
428 	return l->mtu - INT_H_SIZE;
429 #endif
430 }
431 
432 u16 tipc_link_rcv_nxt(struct tipc_link *l)
433 {
434 	return l->rcv_nxt;
435 }
436 
437 u16 tipc_link_acked(struct tipc_link *l)
438 {
439 	return l->acked;
440 }
441 
442 char *tipc_link_name(struct tipc_link *l)
443 {
444 	return l->name;
445 }
446 
447 u32 tipc_link_state(struct tipc_link *l)
448 {
449 	return l->state;
450 }
451 
452 /**
453  * tipc_link_create - create a new link
454  * @net: pointer to associated network namespace
455  * @if_name: associated interface name
456  * @bearer_id: id (index) of associated bearer
457  * @tolerance: link tolerance to be used by link
458  * @net_plane: network plane (A,B,c..) this link belongs to
459  * @mtu: mtu to be advertised by link
460  * @priority: priority to be used by link
461  * @min_win: minimal send window to be used by link
462  * @max_win: maximal send window to be used by link
463  * @session: session to be used by link
464  * @peer: node id of peer node
465  * @peer_caps: bitmap describing peer node capabilities
466  * @bc_sndlink: the namespace global link used for broadcast sending
467  * @bc_rcvlink: the peer specific link used for broadcast reception
468  * @inputq: queue to put messages ready for delivery
469  * @namedq: queue to put binding table update messages ready for delivery
470  * @link: return value, pointer to put the created link
471  * @self: local unicast link id
472  * @peer_id: 128-bit ID of peer
473  *
474  * Return: true if link was created, otherwise false
475  */
476 bool tipc_link_create(struct net *net, char *if_name, int bearer_id,
477 		      int tolerance, char net_plane, u32 mtu, int priority,
478 		      u32 min_win, u32 max_win, u32 session, u32 self,
479 		      u32 peer, u8 *peer_id, u16 peer_caps,
480 		      struct tipc_link *bc_sndlink,
481 		      struct tipc_link *bc_rcvlink,
482 		      struct sk_buff_head *inputq,
483 		      struct sk_buff_head *namedq,
484 		      struct tipc_link **link)
485 {
486 	char peer_str[NODE_ID_STR_LEN] = {0,};
487 	char self_str[NODE_ID_STR_LEN] = {0,};
488 	struct tipc_link *l;
489 
490 	l = kzalloc(sizeof(*l), GFP_ATOMIC);
491 	if (!l)
492 		return false;
493 	*link = l;
494 	l->session = session;
495 
496 	/* Set link name for unicast links only */
497 	if (peer_id) {
498 		tipc_nodeid2string(self_str, tipc_own_id(net));
499 		if (strlen(self_str) > 16)
500 			sprintf(self_str, "%x", self);
501 		tipc_nodeid2string(peer_str, peer_id);
502 		if (strlen(peer_str) > 16)
503 			sprintf(peer_str, "%x", peer);
504 	}
505 	/* Peer i/f name will be completed by reset/activate message */
506 	snprintf(l->name, sizeof(l->name), "%s:%s-%s:unknown",
507 		 self_str, if_name, peer_str);
508 
509 	strcpy(l->if_name, if_name);
510 	l->addr = peer;
511 	l->peer_caps = peer_caps;
512 	l->net = net;
513 	l->in_session = false;
514 	l->bearer_id = bearer_id;
515 	l->tolerance = tolerance;
516 	if (bc_rcvlink)
517 		bc_rcvlink->tolerance = tolerance;
518 	l->net_plane = net_plane;
519 	l->advertised_mtu = mtu;
520 	l->mtu = mtu;
521 	l->priority = priority;
522 	tipc_link_set_queue_limits(l, min_win, max_win);
523 	l->ackers = 1;
524 	l->bc_sndlink = bc_sndlink;
525 	l->bc_rcvlink = bc_rcvlink;
526 	l->inputq = inputq;
527 	l->namedq = namedq;
528 	l->state = LINK_RESETTING;
529 	__skb_queue_head_init(&l->transmq);
530 	__skb_queue_head_init(&l->backlogq);
531 	__skb_queue_head_init(&l->deferdq);
532 	__skb_queue_head_init(&l->failover_deferdq);
533 	skb_queue_head_init(&l->wakeupq);
534 	skb_queue_head_init(l->inputq);
535 	return true;
536 }
537 
538 /**
539  * tipc_link_bc_create - create new link to be used for broadcast
540  * @net: pointer to associated network namespace
541  * @mtu: mtu to be used initially if no peers
542  * @min_win: minimal send window to be used by link
543  * @max_win: maximal send window to be used by link
544  * @inputq: queue to put messages ready for delivery
545  * @namedq: queue to put binding table update messages ready for delivery
546  * @link: return value, pointer to put the created link
547  * @ownnode: identity of own node
548  * @peer: node id of peer node
549  * @peer_id: 128-bit ID of peer
550  * @peer_caps: bitmap describing peer node capabilities
551  * @bc_sndlink: the namespace global link used for broadcast sending
552  *
553  * Return: true if link was created, otherwise false
554  */
555 bool tipc_link_bc_create(struct net *net, u32 ownnode, u32 peer, u8 *peer_id,
556 			 int mtu, u32 min_win, u32 max_win, u16 peer_caps,
557 			 struct sk_buff_head *inputq,
558 			 struct sk_buff_head *namedq,
559 			 struct tipc_link *bc_sndlink,
560 			 struct tipc_link **link)
561 {
562 	struct tipc_link *l;
563 
564 	if (!tipc_link_create(net, "", MAX_BEARERS, 0, 'Z', mtu, 0, min_win,
565 			      max_win, 0, ownnode, peer, NULL, peer_caps,
566 			      bc_sndlink, NULL, inputq, namedq, link))
567 		return false;
568 
569 	l = *link;
570 	if (peer_id) {
571 		char peer_str[NODE_ID_STR_LEN] = {0,};
572 
573 		tipc_nodeid2string(peer_str, peer_id);
574 		if (strlen(peer_str) > 16)
575 			sprintf(peer_str, "%x", peer);
576 		/* Broadcast receiver link name: "broadcast-link:<peer>" */
577 		snprintf(l->name, sizeof(l->name), "%s:%s", tipc_bclink_name,
578 			 peer_str);
579 	} else {
580 		strcpy(l->name, tipc_bclink_name);
581 	}
582 	trace_tipc_link_reset(l, TIPC_DUMP_ALL, "bclink created!");
583 	tipc_link_reset(l);
584 	l->state = LINK_RESET;
585 	l->ackers = 0;
586 	l->bc_rcvlink = l;
587 
588 	/* Broadcast send link is always up */
589 	if (link_is_bc_sndlink(l))
590 		l->state = LINK_ESTABLISHED;
591 
592 	/* Disable replicast if even a single peer doesn't support it */
593 	if (link_is_bc_rcvlink(l) && !(peer_caps & TIPC_BCAST_RCAST))
594 		tipc_bcast_toggle_rcast(net, false);
595 
596 	return true;
597 }
598 
599 /**
600  * tipc_link_fsm_evt - link finite state machine
601  * @l: pointer to link
602  * @evt: state machine event to be processed
603  */
604 int tipc_link_fsm_evt(struct tipc_link *l, int evt)
605 {
606 	int rc = 0;
607 	int old_state = l->state;
608 
609 	switch (l->state) {
610 	case LINK_RESETTING:
611 		switch (evt) {
612 		case LINK_PEER_RESET_EVT:
613 			l->state = LINK_PEER_RESET;
614 			break;
615 		case LINK_RESET_EVT:
616 			l->state = LINK_RESET;
617 			break;
618 		case LINK_FAILURE_EVT:
619 		case LINK_FAILOVER_BEGIN_EVT:
620 		case LINK_ESTABLISH_EVT:
621 		case LINK_FAILOVER_END_EVT:
622 		case LINK_SYNCH_BEGIN_EVT:
623 		case LINK_SYNCH_END_EVT:
624 		default:
625 			goto illegal_evt;
626 		}
627 		break;
628 	case LINK_RESET:
629 		switch (evt) {
630 		case LINK_PEER_RESET_EVT:
631 			l->state = LINK_ESTABLISHING;
632 			break;
633 		case LINK_FAILOVER_BEGIN_EVT:
634 			l->state = LINK_FAILINGOVER;
635 			break;
636 		case LINK_FAILURE_EVT:
637 		case LINK_RESET_EVT:
638 		case LINK_ESTABLISH_EVT:
639 		case LINK_FAILOVER_END_EVT:
640 			break;
641 		case LINK_SYNCH_BEGIN_EVT:
642 		case LINK_SYNCH_END_EVT:
643 		default:
644 			goto illegal_evt;
645 		}
646 		break;
647 	case LINK_PEER_RESET:
648 		switch (evt) {
649 		case LINK_RESET_EVT:
650 			l->state = LINK_ESTABLISHING;
651 			break;
652 		case LINK_PEER_RESET_EVT:
653 		case LINK_ESTABLISH_EVT:
654 		case LINK_FAILURE_EVT:
655 			break;
656 		case LINK_SYNCH_BEGIN_EVT:
657 		case LINK_SYNCH_END_EVT:
658 		case LINK_FAILOVER_BEGIN_EVT:
659 		case LINK_FAILOVER_END_EVT:
660 		default:
661 			goto illegal_evt;
662 		}
663 		break;
664 	case LINK_FAILINGOVER:
665 		switch (evt) {
666 		case LINK_FAILOVER_END_EVT:
667 			l->state = LINK_RESET;
668 			break;
669 		case LINK_PEER_RESET_EVT:
670 		case LINK_RESET_EVT:
671 		case LINK_ESTABLISH_EVT:
672 		case LINK_FAILURE_EVT:
673 			break;
674 		case LINK_FAILOVER_BEGIN_EVT:
675 		case LINK_SYNCH_BEGIN_EVT:
676 		case LINK_SYNCH_END_EVT:
677 		default:
678 			goto illegal_evt;
679 		}
680 		break;
681 	case LINK_ESTABLISHING:
682 		switch (evt) {
683 		case LINK_ESTABLISH_EVT:
684 			l->state = LINK_ESTABLISHED;
685 			break;
686 		case LINK_FAILOVER_BEGIN_EVT:
687 			l->state = LINK_FAILINGOVER;
688 			break;
689 		case LINK_RESET_EVT:
690 			l->state = LINK_RESET;
691 			break;
692 		case LINK_FAILURE_EVT:
693 		case LINK_PEER_RESET_EVT:
694 		case LINK_SYNCH_BEGIN_EVT:
695 		case LINK_FAILOVER_END_EVT:
696 			break;
697 		case LINK_SYNCH_END_EVT:
698 		default:
699 			goto illegal_evt;
700 		}
701 		break;
702 	case LINK_ESTABLISHED:
703 		switch (evt) {
704 		case LINK_PEER_RESET_EVT:
705 			l->state = LINK_PEER_RESET;
706 			rc |= TIPC_LINK_DOWN_EVT;
707 			break;
708 		case LINK_FAILURE_EVT:
709 			l->state = LINK_RESETTING;
710 			rc |= TIPC_LINK_DOWN_EVT;
711 			break;
712 		case LINK_RESET_EVT:
713 			l->state = LINK_RESET;
714 			break;
715 		case LINK_ESTABLISH_EVT:
716 		case LINK_SYNCH_END_EVT:
717 			break;
718 		case LINK_SYNCH_BEGIN_EVT:
719 			l->state = LINK_SYNCHING;
720 			break;
721 		case LINK_FAILOVER_BEGIN_EVT:
722 		case LINK_FAILOVER_END_EVT:
723 		default:
724 			goto illegal_evt;
725 		}
726 		break;
727 	case LINK_SYNCHING:
728 		switch (evt) {
729 		case LINK_PEER_RESET_EVT:
730 			l->state = LINK_PEER_RESET;
731 			rc |= TIPC_LINK_DOWN_EVT;
732 			break;
733 		case LINK_FAILURE_EVT:
734 			l->state = LINK_RESETTING;
735 			rc |= TIPC_LINK_DOWN_EVT;
736 			break;
737 		case LINK_RESET_EVT:
738 			l->state = LINK_RESET;
739 			break;
740 		case LINK_ESTABLISH_EVT:
741 		case LINK_SYNCH_BEGIN_EVT:
742 			break;
743 		case LINK_SYNCH_END_EVT:
744 			l->state = LINK_ESTABLISHED;
745 			break;
746 		case LINK_FAILOVER_BEGIN_EVT:
747 		case LINK_FAILOVER_END_EVT:
748 		default:
749 			goto illegal_evt;
750 		}
751 		break;
752 	default:
753 		pr_err("Unknown FSM state %x in %s\n", l->state, l->name);
754 	}
755 	trace_tipc_link_fsm(l->name, old_state, l->state, evt);
756 	return rc;
757 illegal_evt:
758 	pr_err("Illegal FSM event %x in state %x on link %s\n",
759 	       evt, l->state, l->name);
760 	trace_tipc_link_fsm(l->name, old_state, l->state, evt);
761 	return rc;
762 }
763 
764 /* link_profile_stats - update statistical profiling of traffic
765  */
766 static void link_profile_stats(struct tipc_link *l)
767 {
768 	struct sk_buff *skb;
769 	struct tipc_msg *msg;
770 	int length;
771 
772 	/* Update counters used in statistical profiling of send traffic */
773 	l->stats.accu_queue_sz += skb_queue_len(&l->transmq);
774 	l->stats.queue_sz_counts++;
775 
776 	skb = skb_peek(&l->transmq);
777 	if (!skb)
778 		return;
779 	msg = buf_msg(skb);
780 	length = msg_size(msg);
781 
782 	if (msg_user(msg) == MSG_FRAGMENTER) {
783 		if (msg_type(msg) != FIRST_FRAGMENT)
784 			return;
785 		length = msg_size(msg_inner_hdr(msg));
786 	}
787 	l->stats.msg_lengths_total += length;
788 	l->stats.msg_length_counts++;
789 	if (length <= 64)
790 		l->stats.msg_length_profile[0]++;
791 	else if (length <= 256)
792 		l->stats.msg_length_profile[1]++;
793 	else if (length <= 1024)
794 		l->stats.msg_length_profile[2]++;
795 	else if (length <= 4096)
796 		l->stats.msg_length_profile[3]++;
797 	else if (length <= 16384)
798 		l->stats.msg_length_profile[4]++;
799 	else if (length <= 32768)
800 		l->stats.msg_length_profile[5]++;
801 	else
802 		l->stats.msg_length_profile[6]++;
803 }
804 
805 /**
806  * tipc_link_too_silent - check if link is "too silent"
807  * @l: tipc link to be checked
808  *
809  * Return: true if the link 'silent_intv_cnt' is about to reach the
810  * 'abort_limit' value, otherwise false
811  */
812 bool tipc_link_too_silent(struct tipc_link *l)
813 {
814 	return (l->silent_intv_cnt + 2 > l->abort_limit);
815 }
816 
817 /* tipc_link_timeout - perform periodic task as instructed from node timeout
818  */
819 int tipc_link_timeout(struct tipc_link *l, struct sk_buff_head *xmitq)
820 {
821 	int mtyp = 0;
822 	int rc = 0;
823 	bool state = false;
824 	bool probe = false;
825 	bool setup = false;
826 	u16 bc_snt = l->bc_sndlink->snd_nxt - 1;
827 	u16 bc_acked = l->bc_rcvlink->acked;
828 	struct tipc_mon_state *mstate = &l->mon_state;
829 
830 	trace_tipc_link_timeout(l, TIPC_DUMP_NONE, " ");
831 	trace_tipc_link_too_silent(l, TIPC_DUMP_ALL, " ");
832 	switch (l->state) {
833 	case LINK_ESTABLISHED:
834 	case LINK_SYNCHING:
835 		mtyp = STATE_MSG;
836 		link_profile_stats(l);
837 		tipc_mon_get_state(l->net, l->addr, mstate, l->bearer_id);
838 		if (mstate->reset || (l->silent_intv_cnt > l->abort_limit))
839 			return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
840 		state = bc_acked != bc_snt;
841 		state |= l->bc_rcvlink->rcv_unacked;
842 		state |= l->rcv_unacked;
843 		state |= !skb_queue_empty(&l->transmq);
844 		probe = mstate->probing;
845 		probe |= l->silent_intv_cnt;
846 		if (probe || mstate->monitoring)
847 			l->silent_intv_cnt++;
848 		probe |= !skb_queue_empty(&l->deferdq);
849 		if (l->snd_nxt == l->checkpoint) {
850 			tipc_link_update_cwin(l, 0, 0);
851 			probe = true;
852 		}
853 		l->checkpoint = l->snd_nxt;
854 		break;
855 	case LINK_RESET:
856 		setup = l->rst_cnt++ <= 4;
857 		setup |= !(l->rst_cnt % 16);
858 		mtyp = RESET_MSG;
859 		break;
860 	case LINK_ESTABLISHING:
861 		setup = true;
862 		mtyp = ACTIVATE_MSG;
863 		break;
864 	case LINK_PEER_RESET:
865 	case LINK_RESETTING:
866 	case LINK_FAILINGOVER:
867 		break;
868 	default:
869 		break;
870 	}
871 
872 	if (state || probe || setup)
873 		tipc_link_build_proto_msg(l, mtyp, probe, 0, 0, 0, 0, xmitq);
874 
875 	return rc;
876 }
877 
878 /**
879  * link_schedule_user - schedule a message sender for wakeup after congestion
880  * @l: congested link
881  * @hdr: header of message that is being sent
882  * Create pseudo msg to send back to user when congestion abates
883  */
884 static int link_schedule_user(struct tipc_link *l, struct tipc_msg *hdr)
885 {
886 	u32 dnode = tipc_own_addr(l->net);
887 	u32 dport = msg_origport(hdr);
888 	struct sk_buff *skb;
889 
890 	/* Create and schedule wakeup pseudo message */
891 	skb = tipc_msg_create(SOCK_WAKEUP, 0, INT_H_SIZE, 0,
892 			      dnode, l->addr, dport, 0, 0);
893 	if (!skb)
894 		return -ENOBUFS;
895 	msg_set_dest_droppable(buf_msg(skb), true);
896 	TIPC_SKB_CB(skb)->chain_imp = msg_importance(hdr);
897 	skb_queue_tail(&l->wakeupq, skb);
898 	l->stats.link_congs++;
899 	trace_tipc_link_conges(l, TIPC_DUMP_ALL, "wakeup scheduled!");
900 	return -ELINKCONG;
901 }
902 
903 /**
904  * link_prepare_wakeup - prepare users for wakeup after congestion
905  * @l: congested link
906  * Wake up a number of waiting users, as permitted by available space
907  * in the send queue
908  */
909 static void link_prepare_wakeup(struct tipc_link *l)
910 {
911 	struct sk_buff_head *wakeupq = &l->wakeupq;
912 	struct sk_buff_head *inputq = l->inputq;
913 	struct sk_buff *skb, *tmp;
914 	struct sk_buff_head tmpq;
915 	int avail[5] = {0,};
916 	int imp = 0;
917 
918 	__skb_queue_head_init(&tmpq);
919 
920 	for (; imp <= TIPC_SYSTEM_IMPORTANCE; imp++)
921 		avail[imp] = l->backlog[imp].limit - l->backlog[imp].len;
922 
923 	skb_queue_walk_safe(wakeupq, skb, tmp) {
924 		imp = TIPC_SKB_CB(skb)->chain_imp;
925 		if (avail[imp] <= 0)
926 			continue;
927 		avail[imp]--;
928 		__skb_unlink(skb, wakeupq);
929 		__skb_queue_tail(&tmpq, skb);
930 	}
931 
932 	spin_lock_bh(&inputq->lock);
933 	skb_queue_splice_tail(&tmpq, inputq);
934 	spin_unlock_bh(&inputq->lock);
935 
936 }
937 
938 /**
939  * tipc_link_set_skb_retransmit_time - set the time at which retransmission of
940  *                                     the given skb should be next attempted
941  * @skb: skb to set a future retransmission time for
942  * @l: link the skb will be transmitted on
943  */
944 static void tipc_link_set_skb_retransmit_time(struct sk_buff *skb,
945 					      struct tipc_link *l)
946 {
947 	if (link_is_bc_sndlink(l))
948 		TIPC_SKB_CB(skb)->nxt_retr = TIPC_BC_RETR_LIM;
949 	else
950 		TIPC_SKB_CB(skb)->nxt_retr = TIPC_UC_RETR_TIME;
951 }
952 
953 void tipc_link_reset(struct tipc_link *l)
954 {
955 	struct sk_buff_head list;
956 	u32 imp;
957 
958 	__skb_queue_head_init(&list);
959 
960 	l->in_session = false;
961 	/* Force re-synch of peer session number before establishing */
962 	l->peer_session--;
963 	l->session++;
964 	l->mtu = l->advertised_mtu;
965 
966 	spin_lock_bh(&l->wakeupq.lock);
967 	skb_queue_splice_init(&l->wakeupq, &list);
968 	spin_unlock_bh(&l->wakeupq.lock);
969 
970 	spin_lock_bh(&l->inputq->lock);
971 	skb_queue_splice_init(&list, l->inputq);
972 	spin_unlock_bh(&l->inputq->lock);
973 
974 	__skb_queue_purge(&l->transmq);
975 	__skb_queue_purge(&l->deferdq);
976 	__skb_queue_purge(&l->backlogq);
977 	__skb_queue_purge(&l->failover_deferdq);
978 	for (imp = 0; imp <= TIPC_SYSTEM_IMPORTANCE; imp++) {
979 		l->backlog[imp].len = 0;
980 		l->backlog[imp].target_bskb = NULL;
981 	}
982 	kfree_skb(l->reasm_buf);
983 	kfree_skb(l->reasm_tnlmsg);
984 	kfree_skb(l->failover_reasm_skb);
985 	l->reasm_buf = NULL;
986 	l->reasm_tnlmsg = NULL;
987 	l->failover_reasm_skb = NULL;
988 	l->rcv_unacked = 0;
989 	l->snd_nxt = 1;
990 	l->rcv_nxt = 1;
991 	l->snd_nxt_state = 1;
992 	l->rcv_nxt_state = 1;
993 	l->acked = 0;
994 	l->last_gap = 0;
995 	kfree(l->last_ga);
996 	l->last_ga = NULL;
997 	l->silent_intv_cnt = 0;
998 	l->rst_cnt = 0;
999 	l->bc_peer_is_up = false;
1000 	memset(&l->mon_state, 0, sizeof(l->mon_state));
1001 	tipc_link_reset_stats(l);
1002 }
1003 
1004 /**
1005  * tipc_link_xmit(): enqueue buffer list according to queue situation
1006  * @l: link to use
1007  * @list: chain of buffers containing message
1008  * @xmitq: returned list of packets to be sent by caller
1009  *
1010  * Consumes the buffer chain.
1011  * Messages at TIPC_SYSTEM_IMPORTANCE are always accepted
1012  * Return: 0 if success, or errno: -ELINKCONG, -EMSGSIZE or -ENOBUFS
1013  */
1014 int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *list,
1015 		   struct sk_buff_head *xmitq)
1016 {
1017 	struct sk_buff_head *backlogq = &l->backlogq;
1018 	struct sk_buff_head *transmq = &l->transmq;
1019 	struct sk_buff *skb, *_skb;
1020 	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
1021 	u16 ack = l->rcv_nxt - 1;
1022 	u16 seqno = l->snd_nxt;
1023 	int pkt_cnt = skb_queue_len(list);
1024 	unsigned int mss = tipc_link_mss(l);
1025 	unsigned int cwin = l->window;
1026 	unsigned int mtu = l->mtu;
1027 	struct tipc_msg *hdr;
1028 	bool new_bundle;
1029 	int rc = 0;
1030 	int imp;
1031 
1032 	if (pkt_cnt <= 0)
1033 		return 0;
1034 
1035 	hdr = buf_msg(skb_peek(list));
1036 	if (unlikely(msg_size(hdr) > mtu)) {
1037 		pr_warn("Too large msg, purging xmit list %d %d %d %d %d!\n",
1038 			skb_queue_len(list), msg_user(hdr),
1039 			msg_type(hdr), msg_size(hdr), mtu);
1040 		__skb_queue_purge(list);
1041 		return -EMSGSIZE;
1042 	}
1043 
1044 	imp = msg_importance(hdr);
1045 	/* Allow oversubscription of one data msg per source at congestion */
1046 	if (unlikely(l->backlog[imp].len >= l->backlog[imp].limit)) {
1047 		if (imp == TIPC_SYSTEM_IMPORTANCE) {
1048 			pr_warn("%s<%s>, link overflow", link_rst_msg, l->name);
1049 			return -ENOBUFS;
1050 		}
1051 		rc = link_schedule_user(l, hdr);
1052 	}
1053 
1054 	if (pkt_cnt > 1) {
1055 		l->stats.sent_fragmented++;
1056 		l->stats.sent_fragments += pkt_cnt;
1057 	}
1058 
1059 	/* Prepare each packet for sending, and add to relevant queue: */
1060 	while ((skb = __skb_dequeue(list))) {
1061 		if (likely(skb_queue_len(transmq) < cwin)) {
1062 			hdr = buf_msg(skb);
1063 			msg_set_seqno(hdr, seqno);
1064 			msg_set_ack(hdr, ack);
1065 			msg_set_bcast_ack(hdr, bc_ack);
1066 			_skb = skb_clone(skb, GFP_ATOMIC);
1067 			if (!_skb) {
1068 				kfree_skb(skb);
1069 				__skb_queue_purge(list);
1070 				return -ENOBUFS;
1071 			}
1072 			__skb_queue_tail(transmq, skb);
1073 			tipc_link_set_skb_retransmit_time(skb, l);
1074 			__skb_queue_tail(xmitq, _skb);
1075 			TIPC_SKB_CB(skb)->ackers = l->ackers;
1076 			l->rcv_unacked = 0;
1077 			l->stats.sent_pkts++;
1078 			seqno++;
1079 			continue;
1080 		}
1081 		if (tipc_msg_try_bundle(l->backlog[imp].target_bskb, &skb,
1082 					mss, l->addr, &new_bundle)) {
1083 			if (skb) {
1084 				/* Keep a ref. to the skb for next try */
1085 				l->backlog[imp].target_bskb = skb;
1086 				l->backlog[imp].len++;
1087 				__skb_queue_tail(backlogq, skb);
1088 			} else {
1089 				if (new_bundle) {
1090 					l->stats.sent_bundles++;
1091 					l->stats.sent_bundled++;
1092 				}
1093 				l->stats.sent_bundled++;
1094 			}
1095 			continue;
1096 		}
1097 		l->backlog[imp].target_bskb = NULL;
1098 		l->backlog[imp].len += (1 + skb_queue_len(list));
1099 		__skb_queue_tail(backlogq, skb);
1100 		skb_queue_splice_tail_init(list, backlogq);
1101 	}
1102 	l->snd_nxt = seqno;
1103 	return rc;
1104 }
1105 
1106 static void tipc_link_update_cwin(struct tipc_link *l, int released,
1107 				  bool retransmitted)
1108 {
1109 	int bklog_len = skb_queue_len(&l->backlogq);
1110 	struct sk_buff_head *txq = &l->transmq;
1111 	int txq_len = skb_queue_len(txq);
1112 	u16 cwin = l->window;
1113 
1114 	/* Enter fast recovery */
1115 	if (unlikely(retransmitted)) {
1116 		l->ssthresh = max_t(u16, l->window / 2, 300);
1117 		l->window = min_t(u16, l->ssthresh, l->window);
1118 		return;
1119 	}
1120 	/* Enter slow start */
1121 	if (unlikely(!released)) {
1122 		l->ssthresh = max_t(u16, l->window / 2, 300);
1123 		l->window = l->min_win;
1124 		return;
1125 	}
1126 	/* Don't increase window if no pressure on the transmit queue */
1127 	if (txq_len + bklog_len < cwin)
1128 		return;
1129 
1130 	/* Don't increase window if there are holes the transmit queue */
1131 	if (txq_len && l->snd_nxt - buf_seqno(skb_peek(txq)) != txq_len)
1132 		return;
1133 
1134 	l->cong_acks += released;
1135 
1136 	/* Slow start  */
1137 	if (cwin <= l->ssthresh) {
1138 		l->window = min_t(u16, cwin + released, l->max_win);
1139 		return;
1140 	}
1141 	/* Congestion avoidance */
1142 	if (l->cong_acks < cwin)
1143 		return;
1144 	l->window = min_t(u16, ++cwin, l->max_win);
1145 	l->cong_acks = 0;
1146 }
1147 
1148 static void tipc_link_advance_backlog(struct tipc_link *l,
1149 				      struct sk_buff_head *xmitq)
1150 {
1151 	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
1152 	struct sk_buff_head *txq = &l->transmq;
1153 	struct sk_buff *skb, *_skb;
1154 	u16 ack = l->rcv_nxt - 1;
1155 	u16 seqno = l->snd_nxt;
1156 	struct tipc_msg *hdr;
1157 	u16 cwin = l->window;
1158 	u32 imp;
1159 
1160 	while (skb_queue_len(txq) < cwin) {
1161 		skb = skb_peek(&l->backlogq);
1162 		if (!skb)
1163 			break;
1164 		_skb = skb_clone(skb, GFP_ATOMIC);
1165 		if (!_skb)
1166 			break;
1167 		__skb_dequeue(&l->backlogq);
1168 		hdr = buf_msg(skb);
1169 		imp = msg_importance(hdr);
1170 		l->backlog[imp].len--;
1171 		if (unlikely(skb == l->backlog[imp].target_bskb))
1172 			l->backlog[imp].target_bskb = NULL;
1173 		__skb_queue_tail(&l->transmq, skb);
1174 		tipc_link_set_skb_retransmit_time(skb, l);
1175 
1176 		__skb_queue_tail(xmitq, _skb);
1177 		TIPC_SKB_CB(skb)->ackers = l->ackers;
1178 		msg_set_seqno(hdr, seqno);
1179 		msg_set_ack(hdr, ack);
1180 		msg_set_bcast_ack(hdr, bc_ack);
1181 		l->rcv_unacked = 0;
1182 		l->stats.sent_pkts++;
1183 		seqno++;
1184 	}
1185 	l->snd_nxt = seqno;
1186 }
1187 
1188 /**
1189  * link_retransmit_failure() - Detect repeated retransmit failures
1190  * @l: tipc link sender
1191  * @r: tipc link receiver (= l in case of unicast)
1192  * @rc: returned code
1193  *
1194  * Return: true if the repeated retransmit failures happens, otherwise
1195  * false
1196  */
1197 static bool link_retransmit_failure(struct tipc_link *l, struct tipc_link *r,
1198 				    int *rc)
1199 {
1200 	struct sk_buff *skb = skb_peek(&l->transmq);
1201 	struct tipc_msg *hdr;
1202 
1203 	if (!skb)
1204 		return false;
1205 
1206 	if (!TIPC_SKB_CB(skb)->retr_cnt)
1207 		return false;
1208 
1209 	if (!time_after(jiffies, TIPC_SKB_CB(skb)->retr_stamp +
1210 			msecs_to_jiffies(r->tolerance * 10)))
1211 		return false;
1212 
1213 	hdr = buf_msg(skb);
1214 	if (link_is_bc_sndlink(l) && !less(r->acked, msg_seqno(hdr)))
1215 		return false;
1216 
1217 	pr_warn("Retransmission failure on link <%s>\n", l->name);
1218 	link_print(l, "State of link ");
1219 	pr_info("Failed msg: usr %u, typ %u, len %u, err %u\n",
1220 		msg_user(hdr), msg_type(hdr), msg_size(hdr), msg_errcode(hdr));
1221 	pr_info("sqno %u, prev: %x, dest: %x\n",
1222 		msg_seqno(hdr), msg_prevnode(hdr), msg_destnode(hdr));
1223 	pr_info("retr_stamp %d, retr_cnt %d\n",
1224 		jiffies_to_msecs(TIPC_SKB_CB(skb)->retr_stamp),
1225 		TIPC_SKB_CB(skb)->retr_cnt);
1226 
1227 	trace_tipc_list_dump(&l->transmq, true, "retrans failure!");
1228 	trace_tipc_link_dump(l, TIPC_DUMP_NONE, "retrans failure!");
1229 	trace_tipc_link_dump(r, TIPC_DUMP_NONE, "retrans failure!");
1230 
1231 	if (link_is_bc_sndlink(l)) {
1232 		r->state = LINK_RESET;
1233 		*rc |= TIPC_LINK_DOWN_EVT;
1234 	} else {
1235 		*rc |= tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1236 	}
1237 
1238 	return true;
1239 }
1240 
1241 /* tipc_data_input - deliver data and name distr msgs to upper layer
1242  *
1243  * Consumes buffer if message is of right type
1244  * Node lock must be held
1245  */
1246 static bool tipc_data_input(struct tipc_link *l, struct sk_buff *skb,
1247 			    struct sk_buff_head *inputq)
1248 {
1249 	struct sk_buff_head *mc_inputq = l->bc_rcvlink->inputq;
1250 	struct tipc_msg *hdr = buf_msg(skb);
1251 
1252 	switch (msg_user(hdr)) {
1253 	case TIPC_LOW_IMPORTANCE:
1254 	case TIPC_MEDIUM_IMPORTANCE:
1255 	case TIPC_HIGH_IMPORTANCE:
1256 	case TIPC_CRITICAL_IMPORTANCE:
1257 		if (unlikely(msg_in_group(hdr) || msg_mcast(hdr))) {
1258 			skb_queue_tail(mc_inputq, skb);
1259 			return true;
1260 		}
1261 		fallthrough;
1262 	case CONN_MANAGER:
1263 		skb_queue_tail(inputq, skb);
1264 		return true;
1265 	case GROUP_PROTOCOL:
1266 		skb_queue_tail(mc_inputq, skb);
1267 		return true;
1268 	case NAME_DISTRIBUTOR:
1269 		l->bc_rcvlink->state = LINK_ESTABLISHED;
1270 		skb_queue_tail(l->namedq, skb);
1271 		return true;
1272 	case MSG_BUNDLER:
1273 	case TUNNEL_PROTOCOL:
1274 	case MSG_FRAGMENTER:
1275 	case BCAST_PROTOCOL:
1276 		return false;
1277 #ifdef CONFIG_TIPC_CRYPTO
1278 	case MSG_CRYPTO:
1279 		if (sysctl_tipc_key_exchange_enabled &&
1280 		    TIPC_SKB_CB(skb)->decrypted) {
1281 			tipc_crypto_msg_rcv(l->net, skb);
1282 			return true;
1283 		}
1284 		fallthrough;
1285 #endif
1286 	default:
1287 		pr_warn("Dropping received illegal msg type\n");
1288 		kfree_skb(skb);
1289 		return true;
1290 	}
1291 }
1292 
1293 /* tipc_link_input - process packet that has passed link protocol check
1294  *
1295  * Consumes buffer
1296  */
1297 static int tipc_link_input(struct tipc_link *l, struct sk_buff *skb,
1298 			   struct sk_buff_head *inputq,
1299 			   struct sk_buff **reasm_skb)
1300 {
1301 	struct tipc_msg *hdr = buf_msg(skb);
1302 	struct sk_buff *iskb;
1303 	struct sk_buff_head tmpq;
1304 	int usr = msg_user(hdr);
1305 	int pos = 0;
1306 
1307 	if (usr == MSG_BUNDLER) {
1308 		skb_queue_head_init(&tmpq);
1309 		l->stats.recv_bundles++;
1310 		l->stats.recv_bundled += msg_msgcnt(hdr);
1311 		while (tipc_msg_extract(skb, &iskb, &pos))
1312 			tipc_data_input(l, iskb, &tmpq);
1313 		tipc_skb_queue_splice_tail(&tmpq, inputq);
1314 		return 0;
1315 	} else if (usr == MSG_FRAGMENTER) {
1316 		l->stats.recv_fragments++;
1317 		if (tipc_buf_append(reasm_skb, &skb)) {
1318 			l->stats.recv_fragmented++;
1319 			tipc_data_input(l, skb, inputq);
1320 		} else if (!*reasm_skb && !link_is_bc_rcvlink(l)) {
1321 			pr_warn_ratelimited("Unable to build fragment list\n");
1322 			return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1323 		}
1324 		return 0;
1325 	} else if (usr == BCAST_PROTOCOL) {
1326 		tipc_bcast_lock(l->net);
1327 		tipc_link_bc_init_rcv(l->bc_rcvlink, hdr);
1328 		tipc_bcast_unlock(l->net);
1329 	}
1330 
1331 	kfree_skb(skb);
1332 	return 0;
1333 }
1334 
1335 /* tipc_link_tnl_rcv() - receive TUNNEL_PROTOCOL message, drop or process the
1336  *			 inner message along with the ones in the old link's
1337  *			 deferdq
1338  * @l: tunnel link
1339  * @skb: TUNNEL_PROTOCOL message
1340  * @inputq: queue to put messages ready for delivery
1341  */
1342 static int tipc_link_tnl_rcv(struct tipc_link *l, struct sk_buff *skb,
1343 			     struct sk_buff_head *inputq)
1344 {
1345 	struct sk_buff **reasm_skb = &l->failover_reasm_skb;
1346 	struct sk_buff **reasm_tnlmsg = &l->reasm_tnlmsg;
1347 	struct sk_buff_head *fdefq = &l->failover_deferdq;
1348 	struct tipc_msg *hdr = buf_msg(skb);
1349 	struct sk_buff *iskb;
1350 	int ipos = 0;
1351 	int rc = 0;
1352 	u16 seqno;
1353 
1354 	if (msg_type(hdr) == SYNCH_MSG) {
1355 		kfree_skb(skb);
1356 		return 0;
1357 	}
1358 
1359 	/* Not a fragment? */
1360 	if (likely(!msg_nof_fragms(hdr))) {
1361 		if (unlikely(!tipc_msg_extract(skb, &iskb, &ipos))) {
1362 			pr_warn_ratelimited("Unable to extract msg, defq: %d\n",
1363 					    skb_queue_len(fdefq));
1364 			return 0;
1365 		}
1366 		kfree_skb(skb);
1367 	} else {
1368 		/* Set fragment type for buf_append */
1369 		if (msg_fragm_no(hdr) == 1)
1370 			msg_set_type(hdr, FIRST_FRAGMENT);
1371 		else if (msg_fragm_no(hdr) < msg_nof_fragms(hdr))
1372 			msg_set_type(hdr, FRAGMENT);
1373 		else
1374 			msg_set_type(hdr, LAST_FRAGMENT);
1375 
1376 		if (!tipc_buf_append(reasm_tnlmsg, &skb)) {
1377 			/* Successful but non-complete reassembly? */
1378 			if (*reasm_tnlmsg || link_is_bc_rcvlink(l))
1379 				return 0;
1380 			pr_warn_ratelimited("Unable to reassemble tunnel msg\n");
1381 			return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1382 		}
1383 		iskb = skb;
1384 	}
1385 
1386 	do {
1387 		seqno = buf_seqno(iskb);
1388 		if (unlikely(less(seqno, l->drop_point))) {
1389 			kfree_skb(iskb);
1390 			continue;
1391 		}
1392 		if (unlikely(seqno != l->drop_point)) {
1393 			__tipc_skb_queue_sorted(fdefq, seqno, iskb);
1394 			continue;
1395 		}
1396 
1397 		l->drop_point++;
1398 		if (!tipc_data_input(l, iskb, inputq))
1399 			rc |= tipc_link_input(l, iskb, inputq, reasm_skb);
1400 		if (unlikely(rc))
1401 			break;
1402 	} while ((iskb = __tipc_skb_dequeue(fdefq, l->drop_point)));
1403 
1404 	return rc;
1405 }
1406 
1407 /**
1408  * tipc_get_gap_ack_blks - get Gap ACK blocks from PROTOCOL/STATE_MSG
1409  * @ga: returned pointer to the Gap ACK blocks if any
1410  * @l: the tipc link
1411  * @hdr: the PROTOCOL/STATE_MSG header
1412  * @uc: desired Gap ACK blocks type, i.e. unicast (= 1) or broadcast (= 0)
1413  *
1414  * Return: the total Gap ACK blocks size
1415  */
1416 u16 tipc_get_gap_ack_blks(struct tipc_gap_ack_blks **ga, struct tipc_link *l,
1417 			  struct tipc_msg *hdr, bool uc)
1418 {
1419 	struct tipc_gap_ack_blks *p;
1420 	u16 sz = 0;
1421 
1422 	/* Does peer support the Gap ACK blocks feature? */
1423 	if (l->peer_caps & TIPC_GAP_ACK_BLOCK) {
1424 		p = (struct tipc_gap_ack_blks *)msg_data(hdr);
1425 		sz = ntohs(p->len);
1426 		/* Sanity check */
1427 		if (sz == struct_size(p, gacks, size_add(p->ugack_cnt, p->bgack_cnt))) {
1428 			/* Good, check if the desired type exists */
1429 			if ((uc && p->ugack_cnt) || (!uc && p->bgack_cnt))
1430 				goto ok;
1431 		/* Backward compatible: peer might not support bc, but uc? */
1432 		} else if (uc && sz == struct_size(p, gacks, p->ugack_cnt)) {
1433 			if (p->ugack_cnt) {
1434 				p->bgack_cnt = 0;
1435 				goto ok;
1436 			}
1437 		}
1438 	}
1439 	/* Other cases: ignore! */
1440 	p = NULL;
1441 
1442 ok:
1443 	*ga = p;
1444 	return sz;
1445 }
1446 
1447 static u8 __tipc_build_gap_ack_blks(struct tipc_gap_ack_blks *ga,
1448 				    struct tipc_link *l, u8 start_index)
1449 {
1450 	struct tipc_gap_ack *gacks = &ga->gacks[start_index];
1451 	struct sk_buff *skb = skb_peek(&l->deferdq);
1452 	u16 expect, seqno = 0;
1453 	u8 n = 0;
1454 
1455 	if (!skb)
1456 		return 0;
1457 
1458 	expect = buf_seqno(skb);
1459 	skb_queue_walk(&l->deferdq, skb) {
1460 		seqno = buf_seqno(skb);
1461 		if (unlikely(more(seqno, expect))) {
1462 			gacks[n].ack = htons(expect - 1);
1463 			gacks[n].gap = htons(seqno - expect);
1464 			if (++n >= MAX_GAP_ACK_BLKS / 2) {
1465 				pr_info_ratelimited("Gacks on %s: %d, ql: %d!\n",
1466 						    l->name, n,
1467 						    skb_queue_len(&l->deferdq));
1468 				return n;
1469 			}
1470 		} else if (unlikely(less(seqno, expect))) {
1471 			pr_warn("Unexpected skb in deferdq!\n");
1472 			continue;
1473 		}
1474 		expect = seqno + 1;
1475 	}
1476 
1477 	/* last block */
1478 	gacks[n].ack = htons(seqno);
1479 	gacks[n].gap = 0;
1480 	n++;
1481 	return n;
1482 }
1483 
1484 /* tipc_build_gap_ack_blks - build Gap ACK blocks
1485  * @l: tipc unicast link
1486  * @hdr: the tipc message buffer to store the Gap ACK blocks after built
1487  *
1488  * The function builds Gap ACK blocks for both the unicast & broadcast receiver
1489  * links of a certain peer, the buffer after built has the network data format
1490  * as found at the struct tipc_gap_ack_blks definition.
1491  *
1492  * returns the actual allocated memory size
1493  */
1494 static u16 tipc_build_gap_ack_blks(struct tipc_link *l, struct tipc_msg *hdr)
1495 {
1496 	struct tipc_link *bcl = l->bc_rcvlink;
1497 	struct tipc_gap_ack_blks *ga;
1498 	u16 len;
1499 
1500 	ga = (struct tipc_gap_ack_blks *)msg_data(hdr);
1501 
1502 	/* Start with broadcast link first */
1503 	tipc_bcast_lock(bcl->net);
1504 	msg_set_bcast_ack(hdr, bcl->rcv_nxt - 1);
1505 	msg_set_bc_gap(hdr, link_bc_rcv_gap(bcl));
1506 	ga->bgack_cnt = __tipc_build_gap_ack_blks(ga, bcl, 0);
1507 	tipc_bcast_unlock(bcl->net);
1508 
1509 	/* Now for unicast link, but an explicit NACK only (???) */
1510 	ga->ugack_cnt = (msg_seq_gap(hdr)) ?
1511 			__tipc_build_gap_ack_blks(ga, l, ga->bgack_cnt) : 0;
1512 
1513 	/* Total len */
1514 	len = struct_size(ga, gacks, size_add(ga->bgack_cnt, ga->ugack_cnt));
1515 	ga->len = htons(len);
1516 	return len;
1517 }
1518 
1519 /* tipc_link_advance_transmq - advance TIPC link transmq queue by releasing
1520  *			       acked packets, also doing retransmissions if
1521  *			       gaps found
1522  * @l: tipc link with transmq queue to be advanced
1523  * @r: tipc link "receiver" i.e. in case of broadcast (= "l" if unicast)
1524  * @acked: seqno of last packet acked by peer without any gaps before
1525  * @gap: # of gap packets
1526  * @ga: buffer pointer to Gap ACK blocks from peer
1527  * @xmitq: queue for accumulating the retransmitted packets if any
1528  * @retransmitted: returned boolean value if a retransmission is really issued
1529  * @rc: returned code e.g. TIPC_LINK_DOWN_EVT if a repeated retransmit failures
1530  *      happens (- unlikely case)
1531  *
1532  * Return: the number of packets released from the link transmq
1533  */
1534 static int tipc_link_advance_transmq(struct tipc_link *l, struct tipc_link *r,
1535 				     u16 acked, u16 gap,
1536 				     struct tipc_gap_ack_blks *ga,
1537 				     struct sk_buff_head *xmitq,
1538 				     bool *retransmitted, int *rc)
1539 {
1540 	struct tipc_gap_ack_blks *last_ga = r->last_ga, *this_ga = NULL;
1541 	struct tipc_gap_ack *gacks = NULL;
1542 	struct sk_buff *skb, *_skb, *tmp;
1543 	struct tipc_msg *hdr;
1544 	u32 qlen = skb_queue_len(&l->transmq);
1545 	u16 nacked = acked, ngap = gap, gack_cnt = 0;
1546 	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
1547 	u16 ack = l->rcv_nxt - 1;
1548 	u16 seqno, n = 0;
1549 	u16 end = r->acked, start = end, offset = r->last_gap;
1550 	u16 si = (last_ga) ? last_ga->start_index : 0;
1551 	bool is_uc = !link_is_bc_sndlink(l);
1552 	bool bc_has_acked = false;
1553 
1554 	trace_tipc_link_retrans(r, acked + 1, acked + gap, &l->transmq);
1555 
1556 	/* Determine Gap ACK blocks if any for the particular link */
1557 	if (ga && is_uc) {
1558 		/* Get the Gap ACKs, uc part */
1559 		gack_cnt = ga->ugack_cnt;
1560 		gacks = &ga->gacks[ga->bgack_cnt];
1561 	} else if (ga) {
1562 		/* Copy the Gap ACKs, bc part, for later renewal if needed */
1563 		this_ga = kmemdup(ga, struct_size(ga, gacks, ga->bgack_cnt),
1564 				  GFP_ATOMIC);
1565 		if (likely(this_ga)) {
1566 			this_ga->start_index = 0;
1567 			/* Start with the bc Gap ACKs */
1568 			gack_cnt = this_ga->bgack_cnt;
1569 			gacks = &this_ga->gacks[0];
1570 		} else {
1571 			/* Hmm, we can get in trouble..., simply ignore it */
1572 			pr_warn_ratelimited("Ignoring bc Gap ACKs, no memory\n");
1573 		}
1574 	}
1575 
1576 	/* Advance the link transmq */
1577 	skb_queue_walk_safe(&l->transmq, skb, tmp) {
1578 		seqno = buf_seqno(skb);
1579 
1580 next_gap_ack:
1581 		if (less_eq(seqno, nacked)) {
1582 			if (is_uc)
1583 				goto release;
1584 			/* Skip packets peer has already acked */
1585 			if (!more(seqno, r->acked))
1586 				continue;
1587 			/* Get the next of last Gap ACK blocks */
1588 			while (more(seqno, end)) {
1589 				if (!last_ga || si >= last_ga->bgack_cnt)
1590 					break;
1591 				start = end + offset + 1;
1592 				end = ntohs(last_ga->gacks[si].ack);
1593 				offset = ntohs(last_ga->gacks[si].gap);
1594 				si++;
1595 				WARN_ONCE(more(start, end) ||
1596 					  (!offset &&
1597 					   si < last_ga->bgack_cnt) ||
1598 					  si > MAX_GAP_ACK_BLKS,
1599 					  "Corrupted Gap ACK: %d %d %d %d %d\n",
1600 					  start, end, offset, si,
1601 					  last_ga->bgack_cnt);
1602 			}
1603 			/* Check against the last Gap ACK block */
1604 			if (tipc_in_range(seqno, start, end))
1605 				continue;
1606 			/* Update/release the packet peer is acking */
1607 			bc_has_acked = true;
1608 			if (--TIPC_SKB_CB(skb)->ackers)
1609 				continue;
1610 release:
1611 			/* release skb */
1612 			__skb_unlink(skb, &l->transmq);
1613 			kfree_skb(skb);
1614 		} else if (less_eq(seqno, nacked + ngap)) {
1615 			/* First gap: check if repeated retrans failures? */
1616 			if (unlikely(seqno == acked + 1 &&
1617 				     link_retransmit_failure(l, r, rc))) {
1618 				/* Ignore this bc Gap ACKs if any */
1619 				kfree(this_ga);
1620 				this_ga = NULL;
1621 				break;
1622 			}
1623 			/* retransmit skb if unrestricted*/
1624 			if (time_before(jiffies, TIPC_SKB_CB(skb)->nxt_retr))
1625 				continue;
1626 			tipc_link_set_skb_retransmit_time(skb, l);
1627 			_skb = pskb_copy(skb, GFP_ATOMIC);
1628 			if (!_skb)
1629 				continue;
1630 			hdr = buf_msg(_skb);
1631 			msg_set_ack(hdr, ack);
1632 			msg_set_bcast_ack(hdr, bc_ack);
1633 			_skb->priority = TC_PRIO_CONTROL;
1634 			__skb_queue_tail(xmitq, _skb);
1635 			l->stats.retransmitted++;
1636 			if (!is_uc)
1637 				r->stats.retransmitted++;
1638 			*retransmitted = true;
1639 			/* Increase actual retrans counter & mark first time */
1640 			if (!TIPC_SKB_CB(skb)->retr_cnt++)
1641 				TIPC_SKB_CB(skb)->retr_stamp = jiffies;
1642 		} else {
1643 			/* retry with Gap ACK blocks if any */
1644 			if (n >= gack_cnt)
1645 				break;
1646 			nacked = ntohs(gacks[n].ack);
1647 			ngap = ntohs(gacks[n].gap);
1648 			n++;
1649 			goto next_gap_ack;
1650 		}
1651 	}
1652 
1653 	/* Renew last Gap ACK blocks for bc if needed */
1654 	if (bc_has_acked) {
1655 		if (this_ga) {
1656 			kfree(last_ga);
1657 			r->last_ga = this_ga;
1658 			r->last_gap = gap;
1659 		} else if (last_ga) {
1660 			if (less(acked, start)) {
1661 				si--;
1662 				offset = start - acked - 1;
1663 			} else if (less(acked, end)) {
1664 				acked = end;
1665 			}
1666 			if (si < last_ga->bgack_cnt) {
1667 				last_ga->start_index = si;
1668 				r->last_gap = offset;
1669 			} else {
1670 				kfree(last_ga);
1671 				r->last_ga = NULL;
1672 				r->last_gap = 0;
1673 			}
1674 		} else {
1675 			r->last_gap = 0;
1676 		}
1677 		r->acked = acked;
1678 	} else {
1679 		kfree(this_ga);
1680 	}
1681 
1682 	return qlen - skb_queue_len(&l->transmq);
1683 }
1684 
1685 /* tipc_link_build_state_msg: prepare link state message for transmission
1686  *
1687  * Note that sending of broadcast ack is coordinated among nodes, to reduce
1688  * risk of ack storms towards the sender
1689  */
1690 int tipc_link_build_state_msg(struct tipc_link *l, struct sk_buff_head *xmitq)
1691 {
1692 	if (!l)
1693 		return 0;
1694 
1695 	/* Broadcast ACK must be sent via a unicast link => defer to caller */
1696 	if (link_is_bc_rcvlink(l)) {
1697 		if (((l->rcv_nxt ^ tipc_own_addr(l->net)) & 0xf) != 0xf)
1698 			return 0;
1699 		l->rcv_unacked = 0;
1700 
1701 		/* Use snd_nxt to store peer's snd_nxt in broadcast rcv link */
1702 		l->snd_nxt = l->rcv_nxt;
1703 		return TIPC_LINK_SND_STATE;
1704 	}
1705 	/* Unicast ACK */
1706 	l->rcv_unacked = 0;
1707 	l->stats.sent_acks++;
1708 	tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, 0, 0, xmitq);
1709 	return 0;
1710 }
1711 
1712 /* tipc_link_build_reset_msg: prepare link RESET or ACTIVATE message
1713  */
1714 void tipc_link_build_reset_msg(struct tipc_link *l, struct sk_buff_head *xmitq)
1715 {
1716 	int mtyp = RESET_MSG;
1717 	struct sk_buff *skb;
1718 
1719 	if (l->state == LINK_ESTABLISHING)
1720 		mtyp = ACTIVATE_MSG;
1721 
1722 	tipc_link_build_proto_msg(l, mtyp, 0, 0, 0, 0, 0, xmitq);
1723 
1724 	/* Inform peer that this endpoint is going down if applicable */
1725 	skb = skb_peek_tail(xmitq);
1726 	if (skb && (l->state == LINK_RESET))
1727 		msg_set_peer_stopping(buf_msg(skb), 1);
1728 }
1729 
1730 /* tipc_link_build_nack_msg: prepare link nack message for transmission
1731  * Note that sending of broadcast NACK is coordinated among nodes, to
1732  * reduce the risk of NACK storms towards the sender
1733  */
1734 static int tipc_link_build_nack_msg(struct tipc_link *l,
1735 				    struct sk_buff_head *xmitq)
1736 {
1737 	u32 def_cnt = ++l->stats.deferred_recv;
1738 	struct sk_buff_head *dfq = &l->deferdq;
1739 	u32 defq_len = skb_queue_len(dfq);
1740 	int match1, match2;
1741 
1742 	if (link_is_bc_rcvlink(l)) {
1743 		match1 = def_cnt & 0xf;
1744 		match2 = tipc_own_addr(l->net) & 0xf;
1745 		if (match1 == match2)
1746 			return TIPC_LINK_SND_STATE;
1747 		return 0;
1748 	}
1749 
1750 	if (defq_len >= 3 && !((defq_len - 3) % 16)) {
1751 		u16 rcvgap = buf_seqno(skb_peek(dfq)) - l->rcv_nxt;
1752 
1753 		tipc_link_build_proto_msg(l, STATE_MSG, 0, 0,
1754 					  rcvgap, 0, 0, xmitq);
1755 	}
1756 	return 0;
1757 }
1758 
1759 /* tipc_link_rcv - process TIPC packets/messages arriving from off-node
1760  * @l: the link that should handle the message
1761  * @skb: TIPC packet
1762  * @xmitq: queue to place packets to be sent after this call
1763  */
1764 int tipc_link_rcv(struct tipc_link *l, struct sk_buff *skb,
1765 		  struct sk_buff_head *xmitq)
1766 {
1767 	struct sk_buff_head *defq = &l->deferdq;
1768 	struct tipc_msg *hdr = buf_msg(skb);
1769 	u16 seqno, rcv_nxt, win_lim;
1770 	int released = 0;
1771 	int rc = 0;
1772 
1773 	/* Verify and update link state */
1774 	if (unlikely(msg_user(hdr) == LINK_PROTOCOL))
1775 		return tipc_link_proto_rcv(l, skb, xmitq);
1776 
1777 	/* Don't send probe at next timeout expiration */
1778 	l->silent_intv_cnt = 0;
1779 
1780 	do {
1781 		hdr = buf_msg(skb);
1782 		seqno = msg_seqno(hdr);
1783 		rcv_nxt = l->rcv_nxt;
1784 		win_lim = rcv_nxt + TIPC_MAX_LINK_WIN;
1785 
1786 		if (unlikely(!tipc_link_is_up(l))) {
1787 			if (l->state == LINK_ESTABLISHING)
1788 				rc = TIPC_LINK_UP_EVT;
1789 			kfree_skb(skb);
1790 			break;
1791 		}
1792 
1793 		/* Drop if outside receive window */
1794 		if (unlikely(less(seqno, rcv_nxt) || more(seqno, win_lim))) {
1795 			l->stats.duplicates++;
1796 			kfree_skb(skb);
1797 			break;
1798 		}
1799 		released += tipc_link_advance_transmq(l, l, msg_ack(hdr), 0,
1800 						      NULL, NULL, NULL, NULL);
1801 
1802 		/* Defer delivery if sequence gap */
1803 		if (unlikely(seqno != rcv_nxt)) {
1804 			if (!__tipc_skb_queue_sorted(defq, seqno, skb))
1805 				l->stats.duplicates++;
1806 			rc |= tipc_link_build_nack_msg(l, xmitq);
1807 			break;
1808 		}
1809 
1810 		/* Deliver packet */
1811 		l->rcv_nxt++;
1812 		l->stats.recv_pkts++;
1813 
1814 		if (unlikely(msg_user(hdr) == TUNNEL_PROTOCOL))
1815 			rc |= tipc_link_tnl_rcv(l, skb, l->inputq);
1816 		else if (!tipc_data_input(l, skb, l->inputq))
1817 			rc |= tipc_link_input(l, skb, l->inputq, &l->reasm_buf);
1818 		if (unlikely(++l->rcv_unacked >= TIPC_MIN_LINK_WIN))
1819 			rc |= tipc_link_build_state_msg(l, xmitq);
1820 		if (unlikely(rc & ~TIPC_LINK_SND_STATE))
1821 			break;
1822 	} while ((skb = __tipc_skb_dequeue(defq, l->rcv_nxt)));
1823 
1824 	/* Forward queues and wake up waiting users */
1825 	if (released) {
1826 		tipc_link_update_cwin(l, released, 0);
1827 		tipc_link_advance_backlog(l, xmitq);
1828 		if (unlikely(!skb_queue_empty(&l->wakeupq)))
1829 			link_prepare_wakeup(l);
1830 	}
1831 	return rc;
1832 }
1833 
1834 static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
1835 				      bool probe_reply, u16 rcvgap,
1836 				      int tolerance, int priority,
1837 				      struct sk_buff_head *xmitq)
1838 {
1839 	struct tipc_mon_state *mstate = &l->mon_state;
1840 	struct sk_buff_head *dfq = &l->deferdq;
1841 	struct tipc_link *bcl = l->bc_rcvlink;
1842 	struct tipc_msg *hdr;
1843 	struct sk_buff *skb;
1844 	bool node_up = tipc_link_is_up(bcl);
1845 	u16 glen = 0, bc_rcvgap = 0;
1846 	int dlen = 0;
1847 	void *data;
1848 
1849 	/* Don't send protocol message during reset or link failover */
1850 	if (tipc_link_is_blocked(l))
1851 		return;
1852 
1853 	if (!tipc_link_is_up(l) && (mtyp == STATE_MSG))
1854 		return;
1855 
1856 	if ((probe || probe_reply) && !skb_queue_empty(dfq))
1857 		rcvgap = buf_seqno(skb_peek(dfq)) - l->rcv_nxt;
1858 
1859 	skb = tipc_msg_create(LINK_PROTOCOL, mtyp, INT_H_SIZE,
1860 			      tipc_max_domain_size + MAX_GAP_ACK_BLKS_SZ,
1861 			      l->addr, tipc_own_addr(l->net), 0, 0, 0);
1862 	if (!skb)
1863 		return;
1864 
1865 	hdr = buf_msg(skb);
1866 	data = msg_data(hdr);
1867 	msg_set_session(hdr, l->session);
1868 	msg_set_bearer_id(hdr, l->bearer_id);
1869 	msg_set_net_plane(hdr, l->net_plane);
1870 	msg_set_next_sent(hdr, l->snd_nxt);
1871 	msg_set_ack(hdr, l->rcv_nxt - 1);
1872 	msg_set_bcast_ack(hdr, bcl->rcv_nxt - 1);
1873 	msg_set_bc_ack_invalid(hdr, !node_up);
1874 	msg_set_last_bcast(hdr, l->bc_sndlink->snd_nxt - 1);
1875 	msg_set_link_tolerance(hdr, tolerance);
1876 	msg_set_linkprio(hdr, priority);
1877 	msg_set_redundant_link(hdr, node_up);
1878 	msg_set_seq_gap(hdr, 0);
1879 	msg_set_seqno(hdr, l->snd_nxt + U16_MAX / 2);
1880 
1881 	if (mtyp == STATE_MSG) {
1882 		if (l->peer_caps & TIPC_LINK_PROTO_SEQNO)
1883 			msg_set_seqno(hdr, l->snd_nxt_state++);
1884 		msg_set_seq_gap(hdr, rcvgap);
1885 		bc_rcvgap = link_bc_rcv_gap(bcl);
1886 		msg_set_bc_gap(hdr, bc_rcvgap);
1887 		msg_set_probe(hdr, probe);
1888 		msg_set_is_keepalive(hdr, probe || probe_reply);
1889 		if (l->peer_caps & TIPC_GAP_ACK_BLOCK)
1890 			glen = tipc_build_gap_ack_blks(l, hdr);
1891 		tipc_mon_prep(l->net, data + glen, &dlen, mstate, l->bearer_id);
1892 		msg_set_size(hdr, INT_H_SIZE + glen + dlen);
1893 		skb_trim(skb, INT_H_SIZE + glen + dlen);
1894 		l->stats.sent_states++;
1895 		l->rcv_unacked = 0;
1896 	} else {
1897 		/* RESET_MSG or ACTIVATE_MSG */
1898 		if (mtyp == ACTIVATE_MSG) {
1899 			msg_set_dest_session_valid(hdr, 1);
1900 			msg_set_dest_session(hdr, l->peer_session);
1901 		}
1902 		msg_set_max_pkt(hdr, l->advertised_mtu);
1903 		strcpy(data, l->if_name);
1904 		msg_set_size(hdr, INT_H_SIZE + TIPC_MAX_IF_NAME);
1905 		skb_trim(skb, INT_H_SIZE + TIPC_MAX_IF_NAME);
1906 	}
1907 	if (probe)
1908 		l->stats.sent_probes++;
1909 	if (rcvgap)
1910 		l->stats.sent_nacks++;
1911 	if (bc_rcvgap)
1912 		bcl->stats.sent_nacks++;
1913 	skb->priority = TC_PRIO_CONTROL;
1914 	__skb_queue_tail(xmitq, skb);
1915 	trace_tipc_proto_build(skb, false, l->name);
1916 }
1917 
1918 void tipc_link_create_dummy_tnl_msg(struct tipc_link *l,
1919 				    struct sk_buff_head *xmitq)
1920 {
1921 	u32 onode = tipc_own_addr(l->net);
1922 	struct tipc_msg *hdr, *ihdr;
1923 	struct sk_buff_head tnlq;
1924 	struct sk_buff *skb;
1925 	u32 dnode = l->addr;
1926 
1927 	__skb_queue_head_init(&tnlq);
1928 	skb = tipc_msg_create(TUNNEL_PROTOCOL, FAILOVER_MSG,
1929 			      INT_H_SIZE, BASIC_H_SIZE,
1930 			      dnode, onode, 0, 0, 0);
1931 	if (!skb) {
1932 		pr_warn("%sunable to create tunnel packet\n", link_co_err);
1933 		return;
1934 	}
1935 
1936 	hdr = buf_msg(skb);
1937 	msg_set_msgcnt(hdr, 1);
1938 	msg_set_bearer_id(hdr, l->peer_bearer_id);
1939 
1940 	ihdr = (struct tipc_msg *)msg_data(hdr);
1941 	tipc_msg_init(onode, ihdr, TIPC_LOW_IMPORTANCE, TIPC_DIRECT_MSG,
1942 		      BASIC_H_SIZE, dnode);
1943 	msg_set_errcode(ihdr, TIPC_ERR_NO_PORT);
1944 	__skb_queue_tail(&tnlq, skb);
1945 	tipc_link_xmit(l, &tnlq, xmitq);
1946 }
1947 
1948 /* tipc_link_tnl_prepare(): prepare and return a list of tunnel packets
1949  * with contents of the link's transmit and backlog queues.
1950  */
1951 void tipc_link_tnl_prepare(struct tipc_link *l, struct tipc_link *tnl,
1952 			   int mtyp, struct sk_buff_head *xmitq)
1953 {
1954 	struct sk_buff_head *fdefq = &tnl->failover_deferdq;
1955 	struct sk_buff *skb, *tnlskb;
1956 	struct tipc_msg *hdr, tnlhdr;
1957 	struct sk_buff_head *queue = &l->transmq;
1958 	struct sk_buff_head tmpxq, tnlq, frags;
1959 	u16 pktlen, pktcnt, seqno = l->snd_nxt;
1960 	bool pktcnt_need_update = false;
1961 	u16 syncpt;
1962 	int rc;
1963 
1964 	if (!tnl)
1965 		return;
1966 
1967 	__skb_queue_head_init(&tnlq);
1968 	/* Link Synching:
1969 	 * From now on, send only one single ("dummy") SYNCH message
1970 	 * to peer. The SYNCH message does not contain any data, just
1971 	 * a header conveying the synch point to the peer.
1972 	 */
1973 	if (mtyp == SYNCH_MSG && (tnl->peer_caps & TIPC_TUNNEL_ENHANCED)) {
1974 		tnlskb = tipc_msg_create(TUNNEL_PROTOCOL, SYNCH_MSG,
1975 					 INT_H_SIZE, 0, l->addr,
1976 					 tipc_own_addr(l->net),
1977 					 0, 0, 0);
1978 		if (!tnlskb) {
1979 			pr_warn("%sunable to create dummy SYNCH_MSG\n",
1980 				link_co_err);
1981 			return;
1982 		}
1983 
1984 		hdr = buf_msg(tnlskb);
1985 		syncpt = l->snd_nxt + skb_queue_len(&l->backlogq) - 1;
1986 		msg_set_syncpt(hdr, syncpt);
1987 		msg_set_bearer_id(hdr, l->peer_bearer_id);
1988 		__skb_queue_tail(&tnlq, tnlskb);
1989 		tipc_link_xmit(tnl, &tnlq, xmitq);
1990 		return;
1991 	}
1992 
1993 	__skb_queue_head_init(&tmpxq);
1994 	__skb_queue_head_init(&frags);
1995 	/* At least one packet required for safe algorithm => add dummy */
1996 	skb = tipc_msg_create(TIPC_LOW_IMPORTANCE, TIPC_DIRECT_MSG,
1997 			      BASIC_H_SIZE, 0, l->addr, tipc_own_addr(l->net),
1998 			      0, 0, TIPC_ERR_NO_PORT);
1999 	if (!skb) {
2000 		pr_warn("%sunable to create tunnel packet\n", link_co_err);
2001 		return;
2002 	}
2003 	__skb_queue_tail(&tnlq, skb);
2004 	tipc_link_xmit(l, &tnlq, &tmpxq);
2005 	__skb_queue_purge(&tmpxq);
2006 
2007 	/* Initialize reusable tunnel packet header */
2008 	tipc_msg_init(tipc_own_addr(l->net), &tnlhdr, TUNNEL_PROTOCOL,
2009 		      mtyp, INT_H_SIZE, l->addr);
2010 	if (mtyp == SYNCH_MSG)
2011 		pktcnt = l->snd_nxt - buf_seqno(skb_peek(&l->transmq));
2012 	else
2013 		pktcnt = skb_queue_len(&l->transmq);
2014 	pktcnt += skb_queue_len(&l->backlogq);
2015 	msg_set_msgcnt(&tnlhdr, pktcnt);
2016 	msg_set_bearer_id(&tnlhdr, l->peer_bearer_id);
2017 tnl:
2018 	/* Wrap each packet into a tunnel packet */
2019 	skb_queue_walk(queue, skb) {
2020 		hdr = buf_msg(skb);
2021 		if (queue == &l->backlogq)
2022 			msg_set_seqno(hdr, seqno++);
2023 		pktlen = msg_size(hdr);
2024 
2025 		/* Tunnel link MTU is not large enough? This could be
2026 		 * due to:
2027 		 * 1) Link MTU has just changed or set differently;
2028 		 * 2) Or FAILOVER on the top of a SYNCH message
2029 		 *
2030 		 * The 2nd case should not happen if peer supports
2031 		 * TIPC_TUNNEL_ENHANCED
2032 		 */
2033 		if (pktlen > tnl->mtu - INT_H_SIZE) {
2034 			if (mtyp == FAILOVER_MSG &&
2035 			    (tnl->peer_caps & TIPC_TUNNEL_ENHANCED)) {
2036 				rc = tipc_msg_fragment(skb, &tnlhdr, tnl->mtu,
2037 						       &frags);
2038 				if (rc) {
2039 					pr_warn("%sunable to frag msg: rc %d\n",
2040 						link_co_err, rc);
2041 					return;
2042 				}
2043 				pktcnt += skb_queue_len(&frags) - 1;
2044 				pktcnt_need_update = true;
2045 				skb_queue_splice_tail_init(&frags, &tnlq);
2046 				continue;
2047 			}
2048 			/* Unluckily, peer doesn't have TIPC_TUNNEL_ENHANCED
2049 			 * => Just warn it and return!
2050 			 */
2051 			pr_warn_ratelimited("%stoo large msg <%d, %d>: %d!\n",
2052 					    link_co_err, msg_user(hdr),
2053 					    msg_type(hdr), msg_size(hdr));
2054 			return;
2055 		}
2056 
2057 		msg_set_size(&tnlhdr, pktlen + INT_H_SIZE);
2058 		tnlskb = tipc_buf_acquire(pktlen + INT_H_SIZE, GFP_ATOMIC);
2059 		if (!tnlskb) {
2060 			pr_warn("%sunable to send packet\n", link_co_err);
2061 			return;
2062 		}
2063 		skb_copy_to_linear_data(tnlskb, &tnlhdr, INT_H_SIZE);
2064 		skb_copy_to_linear_data_offset(tnlskb, INT_H_SIZE, hdr, pktlen);
2065 		__skb_queue_tail(&tnlq, tnlskb);
2066 	}
2067 	if (queue != &l->backlogq) {
2068 		queue = &l->backlogq;
2069 		goto tnl;
2070 	}
2071 
2072 	if (pktcnt_need_update)
2073 		skb_queue_walk(&tnlq, skb) {
2074 			hdr = buf_msg(skb);
2075 			msg_set_msgcnt(hdr, pktcnt);
2076 		}
2077 
2078 	tipc_link_xmit(tnl, &tnlq, xmitq);
2079 
2080 	if (mtyp == FAILOVER_MSG) {
2081 		tnl->drop_point = l->rcv_nxt;
2082 		tnl->failover_reasm_skb = l->reasm_buf;
2083 		l->reasm_buf = NULL;
2084 
2085 		/* Failover the link's deferdq */
2086 		if (unlikely(!skb_queue_empty(fdefq))) {
2087 			pr_warn("Link failover deferdq not empty: %d!\n",
2088 				skb_queue_len(fdefq));
2089 			__skb_queue_purge(fdefq);
2090 		}
2091 		skb_queue_splice_init(&l->deferdq, fdefq);
2092 	}
2093 }
2094 
2095 /**
2096  * tipc_link_failover_prepare() - prepare tnl for link failover
2097  *
2098  * This is a special version of the precursor - tipc_link_tnl_prepare(),
2099  * see the tipc_node_link_failover() for details
2100  *
2101  * @l: failover link
2102  * @tnl: tunnel link
2103  * @xmitq: queue for messages to be xmited
2104  */
2105 void tipc_link_failover_prepare(struct tipc_link *l, struct tipc_link *tnl,
2106 				struct sk_buff_head *xmitq)
2107 {
2108 	struct sk_buff_head *fdefq = &tnl->failover_deferdq;
2109 
2110 	tipc_link_create_dummy_tnl_msg(tnl, xmitq);
2111 
2112 	/* This failover link endpoint was never established before,
2113 	 * so it has not received anything from peer.
2114 	 * Otherwise, it must be a normal failover situation or the
2115 	 * node has entered SELF_DOWN_PEER_LEAVING and both peer nodes
2116 	 * would have to start over from scratch instead.
2117 	 */
2118 	tnl->drop_point = 1;
2119 	tnl->failover_reasm_skb = NULL;
2120 
2121 	/* Initiate the link's failover deferdq */
2122 	if (unlikely(!skb_queue_empty(fdefq))) {
2123 		pr_warn("Link failover deferdq not empty: %d!\n",
2124 			skb_queue_len(fdefq));
2125 		__skb_queue_purge(fdefq);
2126 	}
2127 }
2128 
2129 /* tipc_link_validate_msg(): validate message against current link state
2130  * Returns true if message should be accepted, otherwise false
2131  */
2132 bool tipc_link_validate_msg(struct tipc_link *l, struct tipc_msg *hdr)
2133 {
2134 	u16 curr_session = l->peer_session;
2135 	u16 session = msg_session(hdr);
2136 	int mtyp = msg_type(hdr);
2137 
2138 	if (msg_user(hdr) != LINK_PROTOCOL)
2139 		return true;
2140 
2141 	switch (mtyp) {
2142 	case RESET_MSG:
2143 		if (!l->in_session)
2144 			return true;
2145 		/* Accept only RESET with new session number */
2146 		return more(session, curr_session);
2147 	case ACTIVATE_MSG:
2148 		if (!l->in_session)
2149 			return true;
2150 		/* Accept only ACTIVATE with new or current session number */
2151 		return !less(session, curr_session);
2152 	case STATE_MSG:
2153 		/* Accept only STATE with current session number */
2154 		if (!l->in_session)
2155 			return false;
2156 		if (session != curr_session)
2157 			return false;
2158 		/* Extra sanity check */
2159 		if (!tipc_link_is_up(l) && msg_ack(hdr))
2160 			return false;
2161 		if (!(l->peer_caps & TIPC_LINK_PROTO_SEQNO))
2162 			return true;
2163 		/* Accept only STATE with new sequence number */
2164 		return !less(msg_seqno(hdr), l->rcv_nxt_state);
2165 	default:
2166 		return false;
2167 	}
2168 }
2169 
2170 /* tipc_link_proto_rcv(): receive link level protocol message :
2171  * Note that network plane id propagates through the network, and may
2172  * change at any time. The node with lowest numerical id determines
2173  * network plane
2174  */
2175 static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
2176 			       struct sk_buff_head *xmitq)
2177 {
2178 	struct tipc_msg *hdr = buf_msg(skb);
2179 	struct tipc_gap_ack_blks *ga = NULL;
2180 	bool reply = msg_probe(hdr), retransmitted = false;
2181 	u32 dlen = msg_data_sz(hdr), glen = 0, msg_max;
2182 	u16 peers_snd_nxt =  msg_next_sent(hdr);
2183 	u16 peers_tol = msg_link_tolerance(hdr);
2184 	u16 peers_prio = msg_linkprio(hdr);
2185 	u16 gap = msg_seq_gap(hdr);
2186 	u16 ack = msg_ack(hdr);
2187 	u16 rcv_nxt = l->rcv_nxt;
2188 	u16 rcvgap = 0;
2189 	int mtyp = msg_type(hdr);
2190 	int rc = 0, released;
2191 	char *if_name;
2192 	void *data;
2193 
2194 	trace_tipc_proto_rcv(skb, false, l->name);
2195 
2196 	if (dlen > U16_MAX)
2197 		goto exit;
2198 
2199 	if (tipc_link_is_blocked(l) || !xmitq)
2200 		goto exit;
2201 
2202 	if (tipc_own_addr(l->net) > msg_prevnode(hdr))
2203 		l->net_plane = msg_net_plane(hdr);
2204 
2205 	if (skb_linearize(skb))
2206 		goto exit;
2207 
2208 	hdr = buf_msg(skb);
2209 	data = msg_data(hdr);
2210 
2211 	if (!tipc_link_validate_msg(l, hdr)) {
2212 		trace_tipc_skb_dump(skb, false, "PROTO invalid (1)!");
2213 		trace_tipc_link_dump(l, TIPC_DUMP_NONE, "PROTO invalid (1)!");
2214 		goto exit;
2215 	}
2216 
2217 	switch (mtyp) {
2218 	case RESET_MSG:
2219 	case ACTIVATE_MSG:
2220 		msg_max = msg_max_pkt(hdr);
2221 		if (msg_max < tipc_bearer_min_mtu(l->net, l->bearer_id))
2222 			break;
2223 		/* Complete own link name with peer's interface name */
2224 		if_name =  strrchr(l->name, ':') + 1;
2225 		if (sizeof(l->name) - (if_name - l->name) <= TIPC_MAX_IF_NAME)
2226 			break;
2227 		if (msg_data_sz(hdr) < TIPC_MAX_IF_NAME)
2228 			break;
2229 		strncpy(if_name, data, TIPC_MAX_IF_NAME);
2230 
2231 		/* Update own tolerance if peer indicates a non-zero value */
2232 		if (tipc_in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL)) {
2233 			l->tolerance = peers_tol;
2234 			l->bc_rcvlink->tolerance = peers_tol;
2235 		}
2236 		/* Update own priority if peer's priority is higher */
2237 		if (tipc_in_range(peers_prio, l->priority + 1, TIPC_MAX_LINK_PRI))
2238 			l->priority = peers_prio;
2239 
2240 		/* If peer is going down we want full re-establish cycle */
2241 		if (msg_peer_stopping(hdr)) {
2242 			rc = tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
2243 			break;
2244 		}
2245 
2246 		/* If this endpoint was re-created while peer was ESTABLISHING
2247 		 * it doesn't know current session number. Force re-synch.
2248 		 */
2249 		if (mtyp == ACTIVATE_MSG && msg_dest_session_valid(hdr) &&
2250 		    l->session != msg_dest_session(hdr)) {
2251 			if (less(l->session, msg_dest_session(hdr)))
2252 				l->session = msg_dest_session(hdr) + 1;
2253 			break;
2254 		}
2255 
2256 		/* ACTIVATE_MSG serves as PEER_RESET if link is already down */
2257 		if (mtyp == RESET_MSG || !tipc_link_is_up(l))
2258 			rc = tipc_link_fsm_evt(l, LINK_PEER_RESET_EVT);
2259 
2260 		/* ACTIVATE_MSG takes up link if it was already locally reset */
2261 		if (mtyp == ACTIVATE_MSG && l->state == LINK_ESTABLISHING)
2262 			rc = TIPC_LINK_UP_EVT;
2263 
2264 		l->peer_session = msg_session(hdr);
2265 		l->in_session = true;
2266 		l->peer_bearer_id = msg_bearer_id(hdr);
2267 		if (l->mtu > msg_max)
2268 			l->mtu = msg_max;
2269 		break;
2270 
2271 	case STATE_MSG:
2272 		/* Validate Gap ACK blocks, drop if invalid */
2273 		glen = tipc_get_gap_ack_blks(&ga, l, hdr, true);
2274 		if (glen > dlen)
2275 			break;
2276 
2277 		l->rcv_nxt_state = msg_seqno(hdr) + 1;
2278 
2279 		/* Update own tolerance if peer indicates a non-zero value */
2280 		if (tipc_in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL)) {
2281 			l->tolerance = peers_tol;
2282 			l->bc_rcvlink->tolerance = peers_tol;
2283 		}
2284 		/* Update own prio if peer indicates a different value */
2285 		if ((peers_prio != l->priority) &&
2286 		    tipc_in_range(peers_prio, 1, TIPC_MAX_LINK_PRI)) {
2287 			l->priority = peers_prio;
2288 			rc = tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
2289 		}
2290 
2291 		l->silent_intv_cnt = 0;
2292 		l->stats.recv_states++;
2293 		if (msg_probe(hdr))
2294 			l->stats.recv_probes++;
2295 
2296 		if (!tipc_link_is_up(l)) {
2297 			if (l->state == LINK_ESTABLISHING)
2298 				rc = TIPC_LINK_UP_EVT;
2299 			break;
2300 		}
2301 
2302 		tipc_mon_rcv(l->net, data + glen, dlen - glen, l->addr,
2303 			     &l->mon_state, l->bearer_id);
2304 
2305 		/* Send NACK if peer has sent pkts we haven't received yet */
2306 		if ((reply || msg_is_keepalive(hdr)) &&
2307 		    more(peers_snd_nxt, rcv_nxt) &&
2308 		    !tipc_link_is_synching(l) &&
2309 		    skb_queue_empty(&l->deferdq))
2310 			rcvgap = peers_snd_nxt - l->rcv_nxt;
2311 		if (rcvgap || reply)
2312 			tipc_link_build_proto_msg(l, STATE_MSG, 0, reply,
2313 						  rcvgap, 0, 0, xmitq);
2314 
2315 		released = tipc_link_advance_transmq(l, l, ack, gap, ga, xmitq,
2316 						     &retransmitted, &rc);
2317 		if (gap)
2318 			l->stats.recv_nacks++;
2319 		if (released || retransmitted)
2320 			tipc_link_update_cwin(l, released, retransmitted);
2321 		if (released)
2322 			tipc_link_advance_backlog(l, xmitq);
2323 		if (unlikely(!skb_queue_empty(&l->wakeupq)))
2324 			link_prepare_wakeup(l);
2325 	}
2326 exit:
2327 	kfree_skb(skb);
2328 	return rc;
2329 }
2330 
2331 /* tipc_link_build_bc_proto_msg() - create broadcast protocol message
2332  */
2333 static bool tipc_link_build_bc_proto_msg(struct tipc_link *l, bool bcast,
2334 					 u16 peers_snd_nxt,
2335 					 struct sk_buff_head *xmitq)
2336 {
2337 	struct sk_buff *skb;
2338 	struct tipc_msg *hdr;
2339 	struct sk_buff *dfrd_skb = skb_peek(&l->deferdq);
2340 	u16 ack = l->rcv_nxt - 1;
2341 	u16 gap_to = peers_snd_nxt - 1;
2342 
2343 	skb = tipc_msg_create(BCAST_PROTOCOL, STATE_MSG, INT_H_SIZE,
2344 			      0, l->addr, tipc_own_addr(l->net), 0, 0, 0);
2345 	if (!skb)
2346 		return false;
2347 	hdr = buf_msg(skb);
2348 	msg_set_last_bcast(hdr, l->bc_sndlink->snd_nxt - 1);
2349 	msg_set_bcast_ack(hdr, ack);
2350 	msg_set_bcgap_after(hdr, ack);
2351 	if (dfrd_skb)
2352 		gap_to = buf_seqno(dfrd_skb) - 1;
2353 	msg_set_bcgap_to(hdr, gap_to);
2354 	msg_set_non_seq(hdr, bcast);
2355 	__skb_queue_tail(xmitq, skb);
2356 	return true;
2357 }
2358 
2359 /* tipc_link_build_bc_init_msg() - synchronize broadcast link endpoints.
2360  *
2361  * Give a newly added peer node the sequence number where it should
2362  * start receiving and acking broadcast packets.
2363  */
2364 static void tipc_link_build_bc_init_msg(struct tipc_link *l,
2365 					struct sk_buff_head *xmitq)
2366 {
2367 	struct sk_buff_head list;
2368 
2369 	__skb_queue_head_init(&list);
2370 	if (!tipc_link_build_bc_proto_msg(l->bc_rcvlink, false, 0, &list))
2371 		return;
2372 	msg_set_bc_ack_invalid(buf_msg(skb_peek(&list)), true);
2373 	tipc_link_xmit(l, &list, xmitq);
2374 }
2375 
2376 /* tipc_link_bc_init_rcv - receive initial broadcast synch data from peer
2377  */
2378 void tipc_link_bc_init_rcv(struct tipc_link *l, struct tipc_msg *hdr)
2379 {
2380 	int mtyp = msg_type(hdr);
2381 	u16 peers_snd_nxt = msg_bc_snd_nxt(hdr);
2382 
2383 	if (tipc_link_is_up(l))
2384 		return;
2385 
2386 	if (msg_user(hdr) == BCAST_PROTOCOL) {
2387 		l->rcv_nxt = peers_snd_nxt;
2388 		l->state = LINK_ESTABLISHED;
2389 		return;
2390 	}
2391 
2392 	if (l->peer_caps & TIPC_BCAST_SYNCH)
2393 		return;
2394 
2395 	if (msg_peer_node_is_up(hdr))
2396 		return;
2397 
2398 	/* Compatibility: accept older, less safe initial synch data */
2399 	if ((mtyp == RESET_MSG) || (mtyp == ACTIVATE_MSG))
2400 		l->rcv_nxt = peers_snd_nxt;
2401 }
2402 
2403 /* tipc_link_bc_sync_rcv - update rcv link according to peer's send state
2404  */
2405 int tipc_link_bc_sync_rcv(struct tipc_link *l, struct tipc_msg *hdr,
2406 			  struct sk_buff_head *xmitq)
2407 {
2408 	u16 peers_snd_nxt = msg_bc_snd_nxt(hdr);
2409 	int rc = 0;
2410 
2411 	if (!tipc_link_is_up(l))
2412 		return rc;
2413 
2414 	if (!msg_peer_node_is_up(hdr))
2415 		return rc;
2416 
2417 	/* Open when peer acknowledges our bcast init msg (pkt #1) */
2418 	if (msg_ack(hdr))
2419 		l->bc_peer_is_up = true;
2420 
2421 	if (!l->bc_peer_is_up)
2422 		return rc;
2423 
2424 	/* Ignore if peers_snd_nxt goes beyond receive window */
2425 	if (more(peers_snd_nxt, l->rcv_nxt + l->window))
2426 		return rc;
2427 
2428 	l->snd_nxt = peers_snd_nxt;
2429 	if (link_bc_rcv_gap(l))
2430 		rc |= TIPC_LINK_SND_STATE;
2431 
2432 	/* Return now if sender supports nack via STATE messages */
2433 	if (l->peer_caps & TIPC_BCAST_STATE_NACK)
2434 		return rc;
2435 
2436 	/* Otherwise, be backwards compatible */
2437 
2438 	if (!more(peers_snd_nxt, l->rcv_nxt)) {
2439 		l->nack_state = BC_NACK_SND_CONDITIONAL;
2440 		return 0;
2441 	}
2442 
2443 	/* Don't NACK if one was recently sent or peeked */
2444 	if (l->nack_state == BC_NACK_SND_SUPPRESS) {
2445 		l->nack_state = BC_NACK_SND_UNCONDITIONAL;
2446 		return 0;
2447 	}
2448 
2449 	/* Conditionally delay NACK sending until next synch rcv */
2450 	if (l->nack_state == BC_NACK_SND_CONDITIONAL) {
2451 		l->nack_state = BC_NACK_SND_UNCONDITIONAL;
2452 		if ((peers_snd_nxt - l->rcv_nxt) < TIPC_MIN_LINK_WIN)
2453 			return 0;
2454 	}
2455 
2456 	/* Send NACK now but suppress next one */
2457 	tipc_link_build_bc_proto_msg(l, true, peers_snd_nxt, xmitq);
2458 	l->nack_state = BC_NACK_SND_SUPPRESS;
2459 	return 0;
2460 }
2461 
2462 int tipc_link_bc_ack_rcv(struct tipc_link *r, u16 acked, u16 gap,
2463 			 struct tipc_gap_ack_blks *ga,
2464 			 struct sk_buff_head *xmitq,
2465 			 struct sk_buff_head *retrq)
2466 {
2467 	struct tipc_link *l = r->bc_sndlink;
2468 	bool unused = false;
2469 	int rc = 0;
2470 
2471 	if (!tipc_link_is_up(r) || !r->bc_peer_is_up)
2472 		return 0;
2473 
2474 	if (gap) {
2475 		l->stats.recv_nacks++;
2476 		r->stats.recv_nacks++;
2477 	}
2478 
2479 	if (less(acked, r->acked) || (acked == r->acked && !gap && !ga))
2480 		return 0;
2481 
2482 	trace_tipc_link_bc_ack(r, acked, gap, &l->transmq);
2483 	tipc_link_advance_transmq(l, r, acked, gap, ga, retrq, &unused, &rc);
2484 
2485 	tipc_link_advance_backlog(l, xmitq);
2486 	if (unlikely(!skb_queue_empty(&l->wakeupq)))
2487 		link_prepare_wakeup(l);
2488 
2489 	return rc;
2490 }
2491 
2492 /* tipc_link_bc_nack_rcv(): receive broadcast nack message
2493  * This function is here for backwards compatibility, since
2494  * no BCAST_PROTOCOL/STATE messages occur from TIPC v2.5.
2495  */
2496 int tipc_link_bc_nack_rcv(struct tipc_link *l, struct sk_buff *skb,
2497 			  struct sk_buff_head *xmitq)
2498 {
2499 	struct tipc_msg *hdr = buf_msg(skb);
2500 	u32 dnode = msg_destnode(hdr);
2501 	int mtyp = msg_type(hdr);
2502 	u16 acked = msg_bcast_ack(hdr);
2503 	u16 from = acked + 1;
2504 	u16 to = msg_bcgap_to(hdr);
2505 	u16 peers_snd_nxt = to + 1;
2506 	int rc = 0;
2507 
2508 	kfree_skb(skb);
2509 
2510 	if (!tipc_link_is_up(l) || !l->bc_peer_is_up)
2511 		return 0;
2512 
2513 	if (mtyp != STATE_MSG)
2514 		return 0;
2515 
2516 	if (dnode == tipc_own_addr(l->net)) {
2517 		rc = tipc_link_bc_ack_rcv(l, acked, to - acked, NULL, xmitq,
2518 					  xmitq);
2519 		l->stats.recv_nacks++;
2520 		return rc;
2521 	}
2522 
2523 	/* Msg for other node => suppress own NACK at next sync if applicable */
2524 	if (more(peers_snd_nxt, l->rcv_nxt) && !less(l->rcv_nxt, from))
2525 		l->nack_state = BC_NACK_SND_SUPPRESS;
2526 
2527 	return 0;
2528 }
2529 
2530 void tipc_link_set_queue_limits(struct tipc_link *l, u32 min_win, u32 max_win)
2531 {
2532 	int max_bulk = TIPC_MAX_PUBL / (l->mtu / ITEM_SIZE);
2533 
2534 	l->min_win = min_win;
2535 	l->ssthresh = max_win;
2536 	l->max_win = max_win;
2537 	l->window = min_win;
2538 	l->backlog[TIPC_LOW_IMPORTANCE].limit      = min_win * 2;
2539 	l->backlog[TIPC_MEDIUM_IMPORTANCE].limit   = min_win * 4;
2540 	l->backlog[TIPC_HIGH_IMPORTANCE].limit     = min_win * 6;
2541 	l->backlog[TIPC_CRITICAL_IMPORTANCE].limit = min_win * 8;
2542 	l->backlog[TIPC_SYSTEM_IMPORTANCE].limit   = max_bulk;
2543 }
2544 
2545 /**
2546  * tipc_link_reset_stats - reset link statistics
2547  * @l: pointer to link
2548  */
2549 void tipc_link_reset_stats(struct tipc_link *l)
2550 {
2551 	memset(&l->stats, 0, sizeof(l->stats));
2552 }
2553 
2554 static void link_print(struct tipc_link *l, const char *str)
2555 {
2556 	struct sk_buff *hskb = skb_peek(&l->transmq);
2557 	u16 head = hskb ? msg_seqno(buf_msg(hskb)) : l->snd_nxt - 1;
2558 	u16 tail = l->snd_nxt - 1;
2559 
2560 	pr_info("%s Link <%s> state %x\n", str, l->name, l->state);
2561 	pr_info("XMTQ: %u [%u-%u], BKLGQ: %u, SNDNX: %u, RCVNX: %u\n",
2562 		skb_queue_len(&l->transmq), head, tail,
2563 		skb_queue_len(&l->backlogq), l->snd_nxt, l->rcv_nxt);
2564 }
2565 
2566 /* Parse and validate nested (link) properties valid for media, bearer and link
2567  */
2568 int tipc_nl_parse_link_prop(struct nlattr *prop, struct nlattr *props[])
2569 {
2570 	int err;
2571 
2572 	err = nla_parse_nested_deprecated(props, TIPC_NLA_PROP_MAX, prop,
2573 					  tipc_nl_prop_policy, NULL);
2574 	if (err)
2575 		return err;
2576 
2577 	if (props[TIPC_NLA_PROP_PRIO]) {
2578 		u32 prio;
2579 
2580 		prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
2581 		if (prio > TIPC_MAX_LINK_PRI)
2582 			return -EINVAL;
2583 	}
2584 
2585 	if (props[TIPC_NLA_PROP_TOL]) {
2586 		u32 tol;
2587 
2588 		tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
2589 		if ((tol < TIPC_MIN_LINK_TOL) || (tol > TIPC_MAX_LINK_TOL))
2590 			return -EINVAL;
2591 	}
2592 
2593 	if (props[TIPC_NLA_PROP_WIN]) {
2594 		u32 max_win;
2595 
2596 		max_win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
2597 		if (max_win < TIPC_DEF_LINK_WIN || max_win > TIPC_MAX_LINK_WIN)
2598 			return -EINVAL;
2599 	}
2600 
2601 	return 0;
2602 }
2603 
2604 static int __tipc_nl_add_stats(struct sk_buff *skb, struct tipc_stats *s)
2605 {
2606 	int i;
2607 	struct nlattr *stats;
2608 
2609 	struct nla_map {
2610 		u32 key;
2611 		u32 val;
2612 	};
2613 
2614 	struct nla_map map[] = {
2615 		{TIPC_NLA_STATS_RX_INFO, 0},
2616 		{TIPC_NLA_STATS_RX_FRAGMENTS, s->recv_fragments},
2617 		{TIPC_NLA_STATS_RX_FRAGMENTED, s->recv_fragmented},
2618 		{TIPC_NLA_STATS_RX_BUNDLES, s->recv_bundles},
2619 		{TIPC_NLA_STATS_RX_BUNDLED, s->recv_bundled},
2620 		{TIPC_NLA_STATS_TX_INFO, 0},
2621 		{TIPC_NLA_STATS_TX_FRAGMENTS, s->sent_fragments},
2622 		{TIPC_NLA_STATS_TX_FRAGMENTED, s->sent_fragmented},
2623 		{TIPC_NLA_STATS_TX_BUNDLES, s->sent_bundles},
2624 		{TIPC_NLA_STATS_TX_BUNDLED, s->sent_bundled},
2625 		{TIPC_NLA_STATS_MSG_PROF_TOT, (s->msg_length_counts) ?
2626 			s->msg_length_counts : 1},
2627 		{TIPC_NLA_STATS_MSG_LEN_CNT, s->msg_length_counts},
2628 		{TIPC_NLA_STATS_MSG_LEN_TOT, s->msg_lengths_total},
2629 		{TIPC_NLA_STATS_MSG_LEN_P0, s->msg_length_profile[0]},
2630 		{TIPC_NLA_STATS_MSG_LEN_P1, s->msg_length_profile[1]},
2631 		{TIPC_NLA_STATS_MSG_LEN_P2, s->msg_length_profile[2]},
2632 		{TIPC_NLA_STATS_MSG_LEN_P3, s->msg_length_profile[3]},
2633 		{TIPC_NLA_STATS_MSG_LEN_P4, s->msg_length_profile[4]},
2634 		{TIPC_NLA_STATS_MSG_LEN_P5, s->msg_length_profile[5]},
2635 		{TIPC_NLA_STATS_MSG_LEN_P6, s->msg_length_profile[6]},
2636 		{TIPC_NLA_STATS_RX_STATES, s->recv_states},
2637 		{TIPC_NLA_STATS_RX_PROBES, s->recv_probes},
2638 		{TIPC_NLA_STATS_RX_NACKS, s->recv_nacks},
2639 		{TIPC_NLA_STATS_RX_DEFERRED, s->deferred_recv},
2640 		{TIPC_NLA_STATS_TX_STATES, s->sent_states},
2641 		{TIPC_NLA_STATS_TX_PROBES, s->sent_probes},
2642 		{TIPC_NLA_STATS_TX_NACKS, s->sent_nacks},
2643 		{TIPC_NLA_STATS_TX_ACKS, s->sent_acks},
2644 		{TIPC_NLA_STATS_RETRANSMITTED, s->retransmitted},
2645 		{TIPC_NLA_STATS_DUPLICATES, s->duplicates},
2646 		{TIPC_NLA_STATS_LINK_CONGS, s->link_congs},
2647 		{TIPC_NLA_STATS_MAX_QUEUE, s->max_queue_sz},
2648 		{TIPC_NLA_STATS_AVG_QUEUE, s->queue_sz_counts ?
2649 			(s->accu_queue_sz / s->queue_sz_counts) : 0}
2650 	};
2651 
2652 	stats = nla_nest_start_noflag(skb, TIPC_NLA_LINK_STATS);
2653 	if (!stats)
2654 		return -EMSGSIZE;
2655 
2656 	for (i = 0; i <  ARRAY_SIZE(map); i++)
2657 		if (nla_put_u32(skb, map[i].key, map[i].val))
2658 			goto msg_full;
2659 
2660 	nla_nest_end(skb, stats);
2661 
2662 	return 0;
2663 msg_full:
2664 	nla_nest_cancel(skb, stats);
2665 
2666 	return -EMSGSIZE;
2667 }
2668 
2669 /* Caller should hold appropriate locks to protect the link */
2670 int __tipc_nl_add_link(struct net *net, struct tipc_nl_msg *msg,
2671 		       struct tipc_link *link, int nlflags)
2672 {
2673 	u32 self = tipc_own_addr(net);
2674 	struct nlattr *attrs;
2675 	struct nlattr *prop;
2676 	void *hdr;
2677 	int err;
2678 
2679 	hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
2680 			  nlflags, TIPC_NL_LINK_GET);
2681 	if (!hdr)
2682 		return -EMSGSIZE;
2683 
2684 	attrs = nla_nest_start_noflag(msg->skb, TIPC_NLA_LINK);
2685 	if (!attrs)
2686 		goto msg_full;
2687 
2688 	if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, link->name))
2689 		goto attr_msg_full;
2690 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_DEST, tipc_cluster_mask(self)))
2691 		goto attr_msg_full;
2692 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_MTU, link->mtu))
2693 		goto attr_msg_full;
2694 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, link->stats.recv_pkts))
2695 		goto attr_msg_full;
2696 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, link->stats.sent_pkts))
2697 		goto attr_msg_full;
2698 
2699 	if (tipc_link_is_up(link))
2700 		if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
2701 			goto attr_msg_full;
2702 	if (link->active)
2703 		if (nla_put_flag(msg->skb, TIPC_NLA_LINK_ACTIVE))
2704 			goto attr_msg_full;
2705 
2706 	prop = nla_nest_start_noflag(msg->skb, TIPC_NLA_LINK_PROP);
2707 	if (!prop)
2708 		goto attr_msg_full;
2709 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
2710 		goto prop_msg_full;
2711 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_TOL, link->tolerance))
2712 		goto prop_msg_full;
2713 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN,
2714 			link->window))
2715 		goto prop_msg_full;
2716 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
2717 		goto prop_msg_full;
2718 	nla_nest_end(msg->skb, prop);
2719 
2720 	err = __tipc_nl_add_stats(msg->skb, &link->stats);
2721 	if (err)
2722 		goto attr_msg_full;
2723 
2724 	nla_nest_end(msg->skb, attrs);
2725 	genlmsg_end(msg->skb, hdr);
2726 
2727 	return 0;
2728 
2729 prop_msg_full:
2730 	nla_nest_cancel(msg->skb, prop);
2731 attr_msg_full:
2732 	nla_nest_cancel(msg->skb, attrs);
2733 msg_full:
2734 	genlmsg_cancel(msg->skb, hdr);
2735 
2736 	return -EMSGSIZE;
2737 }
2738 
2739 static int __tipc_nl_add_bc_link_stat(struct sk_buff *skb,
2740 				      struct tipc_stats *stats)
2741 {
2742 	int i;
2743 	struct nlattr *nest;
2744 
2745 	struct nla_map {
2746 		__u32 key;
2747 		__u32 val;
2748 	};
2749 
2750 	struct nla_map map[] = {
2751 		{TIPC_NLA_STATS_RX_INFO, stats->recv_pkts},
2752 		{TIPC_NLA_STATS_RX_FRAGMENTS, stats->recv_fragments},
2753 		{TIPC_NLA_STATS_RX_FRAGMENTED, stats->recv_fragmented},
2754 		{TIPC_NLA_STATS_RX_BUNDLES, stats->recv_bundles},
2755 		{TIPC_NLA_STATS_RX_BUNDLED, stats->recv_bundled},
2756 		{TIPC_NLA_STATS_TX_INFO, stats->sent_pkts},
2757 		{TIPC_NLA_STATS_TX_FRAGMENTS, stats->sent_fragments},
2758 		{TIPC_NLA_STATS_TX_FRAGMENTED, stats->sent_fragmented},
2759 		{TIPC_NLA_STATS_TX_BUNDLES, stats->sent_bundles},
2760 		{TIPC_NLA_STATS_TX_BUNDLED, stats->sent_bundled},
2761 		{TIPC_NLA_STATS_RX_NACKS, stats->recv_nacks},
2762 		{TIPC_NLA_STATS_RX_DEFERRED, stats->deferred_recv},
2763 		{TIPC_NLA_STATS_TX_NACKS, stats->sent_nacks},
2764 		{TIPC_NLA_STATS_TX_ACKS, stats->sent_acks},
2765 		{TIPC_NLA_STATS_RETRANSMITTED, stats->retransmitted},
2766 		{TIPC_NLA_STATS_DUPLICATES, stats->duplicates},
2767 		{TIPC_NLA_STATS_LINK_CONGS, stats->link_congs},
2768 		{TIPC_NLA_STATS_MAX_QUEUE, stats->max_queue_sz},
2769 		{TIPC_NLA_STATS_AVG_QUEUE, stats->queue_sz_counts ?
2770 			(stats->accu_queue_sz / stats->queue_sz_counts) : 0}
2771 	};
2772 
2773 	nest = nla_nest_start_noflag(skb, TIPC_NLA_LINK_STATS);
2774 	if (!nest)
2775 		return -EMSGSIZE;
2776 
2777 	for (i = 0; i <  ARRAY_SIZE(map); i++)
2778 		if (nla_put_u32(skb, map[i].key, map[i].val))
2779 			goto msg_full;
2780 
2781 	nla_nest_end(skb, nest);
2782 
2783 	return 0;
2784 msg_full:
2785 	nla_nest_cancel(skb, nest);
2786 
2787 	return -EMSGSIZE;
2788 }
2789 
2790 int tipc_nl_add_bc_link(struct net *net, struct tipc_nl_msg *msg,
2791 			struct tipc_link *bcl)
2792 {
2793 	int err;
2794 	void *hdr;
2795 	struct nlattr *attrs;
2796 	struct nlattr *prop;
2797 	u32 bc_mode = tipc_bcast_get_mode(net);
2798 	u32 bc_ratio = tipc_bcast_get_broadcast_ratio(net);
2799 
2800 	if (!bcl)
2801 		return 0;
2802 
2803 	tipc_bcast_lock(net);
2804 
2805 	hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
2806 			  NLM_F_MULTI, TIPC_NL_LINK_GET);
2807 	if (!hdr) {
2808 		tipc_bcast_unlock(net);
2809 		return -EMSGSIZE;
2810 	}
2811 
2812 	attrs = nla_nest_start_noflag(msg->skb, TIPC_NLA_LINK);
2813 	if (!attrs)
2814 		goto msg_full;
2815 
2816 	/* The broadcast link is always up */
2817 	if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
2818 		goto attr_msg_full;
2819 
2820 	if (nla_put_flag(msg->skb, TIPC_NLA_LINK_BROADCAST))
2821 		goto attr_msg_full;
2822 	if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, bcl->name))
2823 		goto attr_msg_full;
2824 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, 0))
2825 		goto attr_msg_full;
2826 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, 0))
2827 		goto attr_msg_full;
2828 
2829 	prop = nla_nest_start_noflag(msg->skb, TIPC_NLA_LINK_PROP);
2830 	if (!prop)
2831 		goto attr_msg_full;
2832 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN, bcl->max_win))
2833 		goto prop_msg_full;
2834 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_BROADCAST, bc_mode))
2835 		goto prop_msg_full;
2836 	if (bc_mode & BCLINK_MODE_SEL)
2837 		if (nla_put_u32(msg->skb, TIPC_NLA_PROP_BROADCAST_RATIO,
2838 				bc_ratio))
2839 			goto prop_msg_full;
2840 	nla_nest_end(msg->skb, prop);
2841 
2842 	err = __tipc_nl_add_bc_link_stat(msg->skb, &bcl->stats);
2843 	if (err)
2844 		goto attr_msg_full;
2845 
2846 	tipc_bcast_unlock(net);
2847 	nla_nest_end(msg->skb, attrs);
2848 	genlmsg_end(msg->skb, hdr);
2849 
2850 	return 0;
2851 
2852 prop_msg_full:
2853 	nla_nest_cancel(msg->skb, prop);
2854 attr_msg_full:
2855 	nla_nest_cancel(msg->skb, attrs);
2856 msg_full:
2857 	tipc_bcast_unlock(net);
2858 	genlmsg_cancel(msg->skb, hdr);
2859 
2860 	return -EMSGSIZE;
2861 }
2862 
2863 void tipc_link_set_tolerance(struct tipc_link *l, u32 tol,
2864 			     struct sk_buff_head *xmitq)
2865 {
2866 	l->tolerance = tol;
2867 	if (l->bc_rcvlink)
2868 		l->bc_rcvlink->tolerance = tol;
2869 	if (tipc_link_is_up(l))
2870 		tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, tol, 0, xmitq);
2871 }
2872 
2873 void tipc_link_set_prio(struct tipc_link *l, u32 prio,
2874 			struct sk_buff_head *xmitq)
2875 {
2876 	l->priority = prio;
2877 	tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, 0, prio, xmitq);
2878 }
2879 
2880 void tipc_link_set_abort_limit(struct tipc_link *l, u32 limit)
2881 {
2882 	l->abort_limit = limit;
2883 }
2884 
2885 /**
2886  * tipc_link_dump - dump TIPC link data
2887  * @l: tipc link to be dumped
2888  * @dqueues: bitmask to decide if any link queue to be dumped?
2889  *           - TIPC_DUMP_NONE: don't dump link queues
2890  *           - TIPC_DUMP_TRANSMQ: dump link transmq queue
2891  *           - TIPC_DUMP_BACKLOGQ: dump link backlog queue
2892  *           - TIPC_DUMP_DEFERDQ: dump link deferd queue
2893  *           - TIPC_DUMP_INPUTQ: dump link input queue
2894  *           - TIPC_DUMP_WAKEUP: dump link wakeup queue
2895  *           - TIPC_DUMP_ALL: dump all the link queues above
2896  * @buf: returned buffer of dump data in format
2897  */
2898 int tipc_link_dump(struct tipc_link *l, u16 dqueues, char *buf)
2899 {
2900 	int i = 0;
2901 	size_t sz = (dqueues) ? LINK_LMAX : LINK_LMIN;
2902 	struct sk_buff_head *list;
2903 	struct sk_buff *hskb, *tskb;
2904 	u32 len;
2905 
2906 	if (!l) {
2907 		i += scnprintf(buf, sz, "link data: (null)\n");
2908 		return i;
2909 	}
2910 
2911 	i += scnprintf(buf, sz, "link data: %x", l->addr);
2912 	i += scnprintf(buf + i, sz - i, " %x", l->state);
2913 	i += scnprintf(buf + i, sz - i, " %u", l->in_session);
2914 	i += scnprintf(buf + i, sz - i, " %u", l->session);
2915 	i += scnprintf(buf + i, sz - i, " %u", l->peer_session);
2916 	i += scnprintf(buf + i, sz - i, " %u", l->snd_nxt);
2917 	i += scnprintf(buf + i, sz - i, " %u", l->rcv_nxt);
2918 	i += scnprintf(buf + i, sz - i, " %u", l->snd_nxt_state);
2919 	i += scnprintf(buf + i, sz - i, " %u", l->rcv_nxt_state);
2920 	i += scnprintf(buf + i, sz - i, " %x", l->peer_caps);
2921 	i += scnprintf(buf + i, sz - i, " %u", l->silent_intv_cnt);
2922 	i += scnprintf(buf + i, sz - i, " %u", l->rst_cnt);
2923 	i += scnprintf(buf + i, sz - i, " %u", 0);
2924 	i += scnprintf(buf + i, sz - i, " %u", 0);
2925 	i += scnprintf(buf + i, sz - i, " %u", l->acked);
2926 
2927 	list = &l->transmq;
2928 	len = skb_queue_len(list);
2929 	hskb = skb_peek(list);
2930 	tskb = skb_peek_tail(list);
2931 	i += scnprintf(buf + i, sz - i, " | %u %u %u", len,
2932 		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
2933 		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
2934 
2935 	list = &l->deferdq;
2936 	len = skb_queue_len(list);
2937 	hskb = skb_peek(list);
2938 	tskb = skb_peek_tail(list);
2939 	i += scnprintf(buf + i, sz - i, " | %u %u %u", len,
2940 		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
2941 		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
2942 
2943 	list = &l->backlogq;
2944 	len = skb_queue_len(list);
2945 	hskb = skb_peek(list);
2946 	tskb = skb_peek_tail(list);
2947 	i += scnprintf(buf + i, sz - i, " | %u %u %u", len,
2948 		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
2949 		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
2950 
2951 	list = l->inputq;
2952 	len = skb_queue_len(list);
2953 	hskb = skb_peek(list);
2954 	tskb = skb_peek_tail(list);
2955 	i += scnprintf(buf + i, sz - i, " | %u %u %u\n", len,
2956 		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
2957 		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
2958 
2959 	if (dqueues & TIPC_DUMP_TRANSMQ) {
2960 		i += scnprintf(buf + i, sz - i, "transmq: ");
2961 		i += tipc_list_dump(&l->transmq, false, buf + i);
2962 	}
2963 	if (dqueues & TIPC_DUMP_BACKLOGQ) {
2964 		i += scnprintf(buf + i, sz - i,
2965 			       "backlogq: <%u %u %u %u %u>, ",
2966 			       l->backlog[TIPC_LOW_IMPORTANCE].len,
2967 			       l->backlog[TIPC_MEDIUM_IMPORTANCE].len,
2968 			       l->backlog[TIPC_HIGH_IMPORTANCE].len,
2969 			       l->backlog[TIPC_CRITICAL_IMPORTANCE].len,
2970 			       l->backlog[TIPC_SYSTEM_IMPORTANCE].len);
2971 		i += tipc_list_dump(&l->backlogq, false, buf + i);
2972 	}
2973 	if (dqueues & TIPC_DUMP_DEFERDQ) {
2974 		i += scnprintf(buf + i, sz - i, "deferdq: ");
2975 		i += tipc_list_dump(&l->deferdq, false, buf + i);
2976 	}
2977 	if (dqueues & TIPC_DUMP_INPUTQ) {
2978 		i += scnprintf(buf + i, sz - i, "inputq: ");
2979 		i += tipc_list_dump(l->inputq, false, buf + i);
2980 	}
2981 	if (dqueues & TIPC_DUMP_WAKEUP) {
2982 		i += scnprintf(buf + i, sz - i, "wakeup: ");
2983 		i += tipc_list_dump(&l->wakeupq, false, buf + i);
2984 	}
2985 
2986 	return i;
2987 }
2988