xref: /openbmc/linux/net/tipc/link.c (revision f20c7d91)
1 /*
2  * net/tipc/link.c: TIPC link code
3  *
4  * Copyright (c) 1996-2007, 2012-2016, Ericsson AB
5  * Copyright (c) 2004-2007, 2010-2013, Wind River Systems
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions are met:
10  *
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. Neither the names of the copyright holders nor the names of its
17  *    contributors may be used to endorse or promote products derived from
18  *    this software without specific prior written permission.
19  *
20  * Alternatively, this software may be distributed under the terms of the
21  * GNU General Public License ("GPL") version 2 as published by the Free
22  * Software Foundation.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
25  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
28  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
29  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
30  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
31  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
32  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
33  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
34  * POSSIBILITY OF SUCH DAMAGE.
35  */
36 
37 #include "core.h"
38 #include "subscr.h"
39 #include "link.h"
40 #include "bcast.h"
41 #include "socket.h"
42 #include "name_distr.h"
43 #include "discover.h"
44 #include "netlink.h"
45 #include "monitor.h"
46 #include "trace.h"
47 #include "crypto.h"
48 
49 #include <linux/pkt_sched.h>
50 
51 struct tipc_stats {
52 	u32 sent_pkts;
53 	u32 recv_pkts;
54 	u32 sent_states;
55 	u32 recv_states;
56 	u32 sent_probes;
57 	u32 recv_probes;
58 	u32 sent_nacks;
59 	u32 recv_nacks;
60 	u32 sent_acks;
61 	u32 sent_bundled;
62 	u32 sent_bundles;
63 	u32 recv_bundled;
64 	u32 recv_bundles;
65 	u32 retransmitted;
66 	u32 sent_fragmented;
67 	u32 sent_fragments;
68 	u32 recv_fragmented;
69 	u32 recv_fragments;
70 	u32 link_congs;		/* # port sends blocked by congestion */
71 	u32 deferred_recv;
72 	u32 duplicates;
73 	u32 max_queue_sz;	/* send queue size high water mark */
74 	u32 accu_queue_sz;	/* used for send queue size profiling */
75 	u32 queue_sz_counts;	/* used for send queue size profiling */
76 	u32 msg_length_counts;	/* used for message length profiling */
77 	u32 msg_lengths_total;	/* used for message length profiling */
78 	u32 msg_length_profile[7]; /* used for msg. length profiling */
79 };
80 
81 /**
82  * struct tipc_link - TIPC link data structure
83  * @addr: network address of link's peer node
84  * @name: link name character string
85  * @media_addr: media address to use when sending messages over link
86  * @timer: link timer
87  * @net: pointer to namespace struct
88  * @refcnt: reference counter for permanent references (owner node & timer)
89  * @peer_session: link session # being used by peer end of link
90  * @peer_bearer_id: bearer id used by link's peer endpoint
91  * @bearer_id: local bearer id used by link
92  * @tolerance: minimum link continuity loss needed to reset link [in ms]
93  * @abort_limit: # of unacknowledged continuity probes needed to reset link
94  * @state: current state of link FSM
95  * @peer_caps: bitmap describing capabilities of peer node
96  * @silent_intv_cnt: # of timer intervals without any reception from peer
97  * @proto_msg: template for control messages generated by link
98  * @pmsg: convenience pointer to "proto_msg" field
99  * @priority: current link priority
100  * @net_plane: current link network plane ('A' through 'H')
101  * @mon_state: cookie with information needed by link monitor
102  * @backlog_limit: backlog queue congestion thresholds (indexed by importance)
103  * @exp_msg_count: # of tunnelled messages expected during link changeover
104  * @reset_rcv_checkpt: seq # of last acknowledged message at time of link reset
105  * @mtu: current maximum packet size for this link
106  * @advertised_mtu: advertised own mtu when link is being established
107  * @transmitq: queue for sent, non-acked messages
108  * @backlogq: queue for messages waiting to be sent
109  * @snt_nxt: next sequence number to use for outbound messages
110  * @ackers: # of peers that needs to ack each packet before it can be released
111  * @acked: # last packet acked by a certain peer. Used for broadcast.
112  * @rcv_nxt: next sequence number to expect for inbound messages
113  * @deferred_queue: deferred queue saved OOS b'cast message received from node
114  * @unacked_window: # of inbound messages rx'd without ack'ing back to peer
115  * @inputq: buffer queue for messages to be delivered upwards
116  * @namedq: buffer queue for name table messages to be delivered upwards
117  * @next_out: ptr to first unsent outbound message in queue
118  * @wakeupq: linked list of wakeup msgs waiting for link congestion to abate
119  * @long_msg_seq_no: next identifier to use for outbound fragmented messages
120  * @reasm_buf: head of partially reassembled inbound message fragments
121  * @bc_rcvr: marks that this is a broadcast receiver link
122  * @stats: collects statistics regarding link activity
123  */
124 struct tipc_link {
125 	u32 addr;
126 	char name[TIPC_MAX_LINK_NAME];
127 	struct net *net;
128 
129 	/* Management and link supervision data */
130 	u16 peer_session;
131 	u16 session;
132 	u16 snd_nxt_state;
133 	u16 rcv_nxt_state;
134 	u32 peer_bearer_id;
135 	u32 bearer_id;
136 	u32 tolerance;
137 	u32 abort_limit;
138 	u32 state;
139 	u16 peer_caps;
140 	bool in_session;
141 	bool active;
142 	u32 silent_intv_cnt;
143 	char if_name[TIPC_MAX_IF_NAME];
144 	u32 priority;
145 	char net_plane;
146 	struct tipc_mon_state mon_state;
147 	u16 rst_cnt;
148 
149 	/* Failover/synch */
150 	u16 drop_point;
151 	struct sk_buff *failover_reasm_skb;
152 	struct sk_buff_head failover_deferdq;
153 
154 	/* Max packet negotiation */
155 	u16 mtu;
156 	u16 advertised_mtu;
157 
158 	/* Sending */
159 	struct sk_buff_head transmq;
160 	struct sk_buff_head backlogq;
161 	struct {
162 		u16 len;
163 		u16 limit;
164 		struct sk_buff *target_bskb;
165 	} backlog[5];
166 	u16 snd_nxt;
167 
168 	/* Reception */
169 	u16 rcv_nxt;
170 	u32 rcv_unacked;
171 	struct sk_buff_head deferdq;
172 	struct sk_buff_head *inputq;
173 	struct sk_buff_head *namedq;
174 
175 	/* Congestion handling */
176 	struct sk_buff_head wakeupq;
177 	u16 window;
178 	u16 min_win;
179 	u16 ssthresh;
180 	u16 max_win;
181 	u16 cong_acks;
182 	u16 checkpoint;
183 
184 	/* Fragmentation/reassembly */
185 	struct sk_buff *reasm_buf;
186 	struct sk_buff *reasm_tnlmsg;
187 
188 	/* Broadcast */
189 	u16 ackers;
190 	u16 acked;
191 	u16 last_gap;
192 	struct tipc_gap_ack_blks *last_ga;
193 	struct tipc_link *bc_rcvlink;
194 	struct tipc_link *bc_sndlink;
195 	u8 nack_state;
196 	bool bc_peer_is_up;
197 
198 	/* Statistics */
199 	struct tipc_stats stats;
200 };
201 
202 /*
203  * Error message prefixes
204  */
205 static const char *link_co_err = "Link tunneling error, ";
206 static const char *link_rst_msg = "Resetting link ";
207 
208 /* Send states for broadcast NACKs
209  */
210 enum {
211 	BC_NACK_SND_CONDITIONAL,
212 	BC_NACK_SND_UNCONDITIONAL,
213 	BC_NACK_SND_SUPPRESS,
214 };
215 
216 #define TIPC_BC_RETR_LIM  (jiffies + msecs_to_jiffies(10))
217 #define TIPC_UC_RETR_TIME (jiffies + msecs_to_jiffies(1))
218 
219 /*
220  * Interval between NACKs when packets arrive out of order
221  */
222 #define TIPC_NACK_INTV (TIPC_MIN_LINK_WIN * 2)
223 
224 /* Link FSM states:
225  */
226 enum {
227 	LINK_ESTABLISHED     = 0xe,
228 	LINK_ESTABLISHING    = 0xe  << 4,
229 	LINK_RESET           = 0x1  << 8,
230 	LINK_RESETTING       = 0x2  << 12,
231 	LINK_PEER_RESET      = 0xd  << 16,
232 	LINK_FAILINGOVER     = 0xf  << 20,
233 	LINK_SYNCHING        = 0xc  << 24
234 };
235 
236 /* Link FSM state checking routines
237  */
238 static int link_is_up(struct tipc_link *l)
239 {
240 	return l->state & (LINK_ESTABLISHED | LINK_SYNCHING);
241 }
242 
243 static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
244 			       struct sk_buff_head *xmitq);
245 static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
246 				      bool probe_reply, u16 rcvgap,
247 				      int tolerance, int priority,
248 				      struct sk_buff_head *xmitq);
249 static void link_print(struct tipc_link *l, const char *str);
250 static int tipc_link_build_nack_msg(struct tipc_link *l,
251 				    struct sk_buff_head *xmitq);
252 static void tipc_link_build_bc_init_msg(struct tipc_link *l,
253 					struct sk_buff_head *xmitq);
254 static u8 __tipc_build_gap_ack_blks(struct tipc_gap_ack_blks *ga,
255 				    struct tipc_link *l, u8 start_index);
256 static u16 tipc_build_gap_ack_blks(struct tipc_link *l, struct tipc_msg *hdr);
257 static int tipc_link_advance_transmq(struct tipc_link *l, struct tipc_link *r,
258 				     u16 acked, u16 gap,
259 				     struct tipc_gap_ack_blks *ga,
260 				     struct sk_buff_head *xmitq,
261 				     bool *retransmitted, int *rc);
262 static void tipc_link_update_cwin(struct tipc_link *l, int released,
263 				  bool retransmitted);
264 /*
265  *  Simple non-static link routines (i.e. referenced outside this file)
266  */
267 bool tipc_link_is_up(struct tipc_link *l)
268 {
269 	return link_is_up(l);
270 }
271 
272 bool tipc_link_peer_is_down(struct tipc_link *l)
273 {
274 	return l->state == LINK_PEER_RESET;
275 }
276 
277 bool tipc_link_is_reset(struct tipc_link *l)
278 {
279 	return l->state & (LINK_RESET | LINK_FAILINGOVER | LINK_ESTABLISHING);
280 }
281 
282 bool tipc_link_is_establishing(struct tipc_link *l)
283 {
284 	return l->state == LINK_ESTABLISHING;
285 }
286 
287 bool tipc_link_is_synching(struct tipc_link *l)
288 {
289 	return l->state == LINK_SYNCHING;
290 }
291 
292 bool tipc_link_is_failingover(struct tipc_link *l)
293 {
294 	return l->state == LINK_FAILINGOVER;
295 }
296 
297 bool tipc_link_is_blocked(struct tipc_link *l)
298 {
299 	return l->state & (LINK_RESETTING | LINK_PEER_RESET | LINK_FAILINGOVER);
300 }
301 
302 static bool link_is_bc_sndlink(struct tipc_link *l)
303 {
304 	return !l->bc_sndlink;
305 }
306 
307 static bool link_is_bc_rcvlink(struct tipc_link *l)
308 {
309 	return ((l->bc_rcvlink == l) && !link_is_bc_sndlink(l));
310 }
311 
312 void tipc_link_set_active(struct tipc_link *l, bool active)
313 {
314 	l->active = active;
315 }
316 
317 u32 tipc_link_id(struct tipc_link *l)
318 {
319 	return l->peer_bearer_id << 16 | l->bearer_id;
320 }
321 
322 int tipc_link_min_win(struct tipc_link *l)
323 {
324 	return l->min_win;
325 }
326 
327 int tipc_link_max_win(struct tipc_link *l)
328 {
329 	return l->max_win;
330 }
331 
332 int tipc_link_prio(struct tipc_link *l)
333 {
334 	return l->priority;
335 }
336 
337 unsigned long tipc_link_tolerance(struct tipc_link *l)
338 {
339 	return l->tolerance;
340 }
341 
342 struct sk_buff_head *tipc_link_inputq(struct tipc_link *l)
343 {
344 	return l->inputq;
345 }
346 
347 char tipc_link_plane(struct tipc_link *l)
348 {
349 	return l->net_plane;
350 }
351 
352 void tipc_link_update_caps(struct tipc_link *l, u16 capabilities)
353 {
354 	l->peer_caps = capabilities;
355 }
356 
357 void tipc_link_add_bc_peer(struct tipc_link *snd_l,
358 			   struct tipc_link *uc_l,
359 			   struct sk_buff_head *xmitq)
360 {
361 	struct tipc_link *rcv_l = uc_l->bc_rcvlink;
362 
363 	snd_l->ackers++;
364 	rcv_l->acked = snd_l->snd_nxt - 1;
365 	snd_l->state = LINK_ESTABLISHED;
366 	tipc_link_build_bc_init_msg(uc_l, xmitq);
367 }
368 
369 void tipc_link_remove_bc_peer(struct tipc_link *snd_l,
370 			      struct tipc_link *rcv_l,
371 			      struct sk_buff_head *xmitq)
372 {
373 	u16 ack = snd_l->snd_nxt - 1;
374 
375 	snd_l->ackers--;
376 	rcv_l->bc_peer_is_up = true;
377 	rcv_l->state = LINK_ESTABLISHED;
378 	tipc_link_bc_ack_rcv(rcv_l, ack, 0, NULL, xmitq, NULL);
379 	trace_tipc_link_reset(rcv_l, TIPC_DUMP_ALL, "bclink removed!");
380 	tipc_link_reset(rcv_l);
381 	rcv_l->state = LINK_RESET;
382 	if (!snd_l->ackers) {
383 		trace_tipc_link_reset(snd_l, TIPC_DUMP_ALL, "zero ackers!");
384 		tipc_link_reset(snd_l);
385 		snd_l->state = LINK_RESET;
386 		__skb_queue_purge(xmitq);
387 	}
388 }
389 
390 int tipc_link_bc_peers(struct tipc_link *l)
391 {
392 	return l->ackers;
393 }
394 
395 static u16 link_bc_rcv_gap(struct tipc_link *l)
396 {
397 	struct sk_buff *skb = skb_peek(&l->deferdq);
398 	u16 gap = 0;
399 
400 	if (more(l->snd_nxt, l->rcv_nxt))
401 		gap = l->snd_nxt - l->rcv_nxt;
402 	if (skb)
403 		gap = buf_seqno(skb) - l->rcv_nxt;
404 	return gap;
405 }
406 
407 void tipc_link_set_mtu(struct tipc_link *l, int mtu)
408 {
409 	l->mtu = mtu;
410 }
411 
412 int tipc_link_mtu(struct tipc_link *l)
413 {
414 	return l->mtu;
415 }
416 
417 int tipc_link_mss(struct tipc_link *l)
418 {
419 #ifdef CONFIG_TIPC_CRYPTO
420 	return l->mtu - INT_H_SIZE - EMSG_OVERHEAD;
421 #else
422 	return l->mtu - INT_H_SIZE;
423 #endif
424 }
425 
426 u16 tipc_link_rcv_nxt(struct tipc_link *l)
427 {
428 	return l->rcv_nxt;
429 }
430 
431 u16 tipc_link_acked(struct tipc_link *l)
432 {
433 	return l->acked;
434 }
435 
436 char *tipc_link_name(struct tipc_link *l)
437 {
438 	return l->name;
439 }
440 
441 u32 tipc_link_state(struct tipc_link *l)
442 {
443 	return l->state;
444 }
445 
446 /**
447  * tipc_link_create - create a new link
448  * @n: pointer to associated node
449  * @if_name: associated interface name
450  * @bearer_id: id (index) of associated bearer
451  * @tolerance: link tolerance to be used by link
452  * @net_plane: network plane (A,B,c..) this link belongs to
453  * @mtu: mtu to be advertised by link
454  * @priority: priority to be used by link
455  * @min_win: minimal send window to be used by link
456  * @max_win: maximal send window to be used by link
457  * @session: session to be used by link
458  * @ownnode: identity of own node
459  * @peer: node id of peer node
460  * @peer_caps: bitmap describing peer node capabilities
461  * @bc_sndlink: the namespace global link used for broadcast sending
462  * @bc_rcvlink: the peer specific link used for broadcast reception
463  * @inputq: queue to put messages ready for delivery
464  * @namedq: queue to put binding table update messages ready for delivery
465  * @link: return value, pointer to put the created link
466  *
467  * Returns true if link was created, otherwise false
468  */
469 bool tipc_link_create(struct net *net, char *if_name, int bearer_id,
470 		      int tolerance, char net_plane, u32 mtu, int priority,
471 		      u32 min_win, u32 max_win, u32 session, u32 self,
472 		      u32 peer, u8 *peer_id, u16 peer_caps,
473 		      struct tipc_link *bc_sndlink,
474 		      struct tipc_link *bc_rcvlink,
475 		      struct sk_buff_head *inputq,
476 		      struct sk_buff_head *namedq,
477 		      struct tipc_link **link)
478 {
479 	char peer_str[NODE_ID_STR_LEN] = {0,};
480 	char self_str[NODE_ID_STR_LEN] = {0,};
481 	struct tipc_link *l;
482 
483 	l = kzalloc(sizeof(*l), GFP_ATOMIC);
484 	if (!l)
485 		return false;
486 	*link = l;
487 	l->session = session;
488 
489 	/* Set link name for unicast links only */
490 	if (peer_id) {
491 		tipc_nodeid2string(self_str, tipc_own_id(net));
492 		if (strlen(self_str) > 16)
493 			sprintf(self_str, "%x", self);
494 		tipc_nodeid2string(peer_str, peer_id);
495 		if (strlen(peer_str) > 16)
496 			sprintf(peer_str, "%x", peer);
497 	}
498 	/* Peer i/f name will be completed by reset/activate message */
499 	snprintf(l->name, sizeof(l->name), "%s:%s-%s:unknown",
500 		 self_str, if_name, peer_str);
501 
502 	strcpy(l->if_name, if_name);
503 	l->addr = peer;
504 	l->peer_caps = peer_caps;
505 	l->net = net;
506 	l->in_session = false;
507 	l->bearer_id = bearer_id;
508 	l->tolerance = tolerance;
509 	if (bc_rcvlink)
510 		bc_rcvlink->tolerance = tolerance;
511 	l->net_plane = net_plane;
512 	l->advertised_mtu = mtu;
513 	l->mtu = mtu;
514 	l->priority = priority;
515 	tipc_link_set_queue_limits(l, min_win, max_win);
516 	l->ackers = 1;
517 	l->bc_sndlink = bc_sndlink;
518 	l->bc_rcvlink = bc_rcvlink;
519 	l->inputq = inputq;
520 	l->namedq = namedq;
521 	l->state = LINK_RESETTING;
522 	__skb_queue_head_init(&l->transmq);
523 	__skb_queue_head_init(&l->backlogq);
524 	__skb_queue_head_init(&l->deferdq);
525 	__skb_queue_head_init(&l->failover_deferdq);
526 	skb_queue_head_init(&l->wakeupq);
527 	skb_queue_head_init(l->inputq);
528 	return true;
529 }
530 
531 /**
532  * tipc_link_bc_create - create new link to be used for broadcast
533  * @n: pointer to associated node
534  * @mtu: mtu to be used initially if no peers
535  * @window: send window to be used
536  * @inputq: queue to put messages ready for delivery
537  * @namedq: queue to put binding table update messages ready for delivery
538  * @link: return value, pointer to put the created link
539  *
540  * Returns true if link was created, otherwise false
541  */
542 bool tipc_link_bc_create(struct net *net, u32 ownnode, u32 peer, u8 *peer_id,
543 			 int mtu, u32 min_win, u32 max_win, u16 peer_caps,
544 			 struct sk_buff_head *inputq,
545 			 struct sk_buff_head *namedq,
546 			 struct tipc_link *bc_sndlink,
547 			 struct tipc_link **link)
548 {
549 	struct tipc_link *l;
550 
551 	if (!tipc_link_create(net, "", MAX_BEARERS, 0, 'Z', mtu, 0, min_win,
552 			      max_win, 0, ownnode, peer, NULL, peer_caps,
553 			      bc_sndlink, NULL, inputq, namedq, link))
554 		return false;
555 
556 	l = *link;
557 	if (peer_id) {
558 		char peer_str[NODE_ID_STR_LEN] = {0,};
559 
560 		tipc_nodeid2string(peer_str, peer_id);
561 		if (strlen(peer_str) > 16)
562 			sprintf(peer_str, "%x", peer);
563 		/* Broadcast receiver link name: "broadcast-link:<peer>" */
564 		snprintf(l->name, sizeof(l->name), "%s:%s", tipc_bclink_name,
565 			 peer_str);
566 	} else {
567 		strcpy(l->name, tipc_bclink_name);
568 	}
569 	trace_tipc_link_reset(l, TIPC_DUMP_ALL, "bclink created!");
570 	tipc_link_reset(l);
571 	l->state = LINK_RESET;
572 	l->ackers = 0;
573 	l->bc_rcvlink = l;
574 
575 	/* Broadcast send link is always up */
576 	if (link_is_bc_sndlink(l))
577 		l->state = LINK_ESTABLISHED;
578 
579 	/* Disable replicast if even a single peer doesn't support it */
580 	if (link_is_bc_rcvlink(l) && !(peer_caps & TIPC_BCAST_RCAST))
581 		tipc_bcast_toggle_rcast(net, false);
582 
583 	return true;
584 }
585 
586 /**
587  * tipc_link_fsm_evt - link finite state machine
588  * @l: pointer to link
589  * @evt: state machine event to be processed
590  */
591 int tipc_link_fsm_evt(struct tipc_link *l, int evt)
592 {
593 	int rc = 0;
594 	int old_state = l->state;
595 
596 	switch (l->state) {
597 	case LINK_RESETTING:
598 		switch (evt) {
599 		case LINK_PEER_RESET_EVT:
600 			l->state = LINK_PEER_RESET;
601 			break;
602 		case LINK_RESET_EVT:
603 			l->state = LINK_RESET;
604 			break;
605 		case LINK_FAILURE_EVT:
606 		case LINK_FAILOVER_BEGIN_EVT:
607 		case LINK_ESTABLISH_EVT:
608 		case LINK_FAILOVER_END_EVT:
609 		case LINK_SYNCH_BEGIN_EVT:
610 		case LINK_SYNCH_END_EVT:
611 		default:
612 			goto illegal_evt;
613 		}
614 		break;
615 	case LINK_RESET:
616 		switch (evt) {
617 		case LINK_PEER_RESET_EVT:
618 			l->state = LINK_ESTABLISHING;
619 			break;
620 		case LINK_FAILOVER_BEGIN_EVT:
621 			l->state = LINK_FAILINGOVER;
622 		case LINK_FAILURE_EVT:
623 		case LINK_RESET_EVT:
624 		case LINK_ESTABLISH_EVT:
625 		case LINK_FAILOVER_END_EVT:
626 			break;
627 		case LINK_SYNCH_BEGIN_EVT:
628 		case LINK_SYNCH_END_EVT:
629 		default:
630 			goto illegal_evt;
631 		}
632 		break;
633 	case LINK_PEER_RESET:
634 		switch (evt) {
635 		case LINK_RESET_EVT:
636 			l->state = LINK_ESTABLISHING;
637 			break;
638 		case LINK_PEER_RESET_EVT:
639 		case LINK_ESTABLISH_EVT:
640 		case LINK_FAILURE_EVT:
641 			break;
642 		case LINK_SYNCH_BEGIN_EVT:
643 		case LINK_SYNCH_END_EVT:
644 		case LINK_FAILOVER_BEGIN_EVT:
645 		case LINK_FAILOVER_END_EVT:
646 		default:
647 			goto illegal_evt;
648 		}
649 		break;
650 	case LINK_FAILINGOVER:
651 		switch (evt) {
652 		case LINK_FAILOVER_END_EVT:
653 			l->state = LINK_RESET;
654 			break;
655 		case LINK_PEER_RESET_EVT:
656 		case LINK_RESET_EVT:
657 		case LINK_ESTABLISH_EVT:
658 		case LINK_FAILURE_EVT:
659 			break;
660 		case LINK_FAILOVER_BEGIN_EVT:
661 		case LINK_SYNCH_BEGIN_EVT:
662 		case LINK_SYNCH_END_EVT:
663 		default:
664 			goto illegal_evt;
665 		}
666 		break;
667 	case LINK_ESTABLISHING:
668 		switch (evt) {
669 		case LINK_ESTABLISH_EVT:
670 			l->state = LINK_ESTABLISHED;
671 			break;
672 		case LINK_FAILOVER_BEGIN_EVT:
673 			l->state = LINK_FAILINGOVER;
674 			break;
675 		case LINK_RESET_EVT:
676 			l->state = LINK_RESET;
677 			break;
678 		case LINK_FAILURE_EVT:
679 		case LINK_PEER_RESET_EVT:
680 		case LINK_SYNCH_BEGIN_EVT:
681 		case LINK_FAILOVER_END_EVT:
682 			break;
683 		case LINK_SYNCH_END_EVT:
684 		default:
685 			goto illegal_evt;
686 		}
687 		break;
688 	case LINK_ESTABLISHED:
689 		switch (evt) {
690 		case LINK_PEER_RESET_EVT:
691 			l->state = LINK_PEER_RESET;
692 			rc |= TIPC_LINK_DOWN_EVT;
693 			break;
694 		case LINK_FAILURE_EVT:
695 			l->state = LINK_RESETTING;
696 			rc |= TIPC_LINK_DOWN_EVT;
697 			break;
698 		case LINK_RESET_EVT:
699 			l->state = LINK_RESET;
700 			break;
701 		case LINK_ESTABLISH_EVT:
702 		case LINK_SYNCH_END_EVT:
703 			break;
704 		case LINK_SYNCH_BEGIN_EVT:
705 			l->state = LINK_SYNCHING;
706 			break;
707 		case LINK_FAILOVER_BEGIN_EVT:
708 		case LINK_FAILOVER_END_EVT:
709 		default:
710 			goto illegal_evt;
711 		}
712 		break;
713 	case LINK_SYNCHING:
714 		switch (evt) {
715 		case LINK_PEER_RESET_EVT:
716 			l->state = LINK_PEER_RESET;
717 			rc |= TIPC_LINK_DOWN_EVT;
718 			break;
719 		case LINK_FAILURE_EVT:
720 			l->state = LINK_RESETTING;
721 			rc |= TIPC_LINK_DOWN_EVT;
722 			break;
723 		case LINK_RESET_EVT:
724 			l->state = LINK_RESET;
725 			break;
726 		case LINK_ESTABLISH_EVT:
727 		case LINK_SYNCH_BEGIN_EVT:
728 			break;
729 		case LINK_SYNCH_END_EVT:
730 			l->state = LINK_ESTABLISHED;
731 			break;
732 		case LINK_FAILOVER_BEGIN_EVT:
733 		case LINK_FAILOVER_END_EVT:
734 		default:
735 			goto illegal_evt;
736 		}
737 		break;
738 	default:
739 		pr_err("Unknown FSM state %x in %s\n", l->state, l->name);
740 	}
741 	trace_tipc_link_fsm(l->name, old_state, l->state, evt);
742 	return rc;
743 illegal_evt:
744 	pr_err("Illegal FSM event %x in state %x on link %s\n",
745 	       evt, l->state, l->name);
746 	trace_tipc_link_fsm(l->name, old_state, l->state, evt);
747 	return rc;
748 }
749 
750 /* link_profile_stats - update statistical profiling of traffic
751  */
752 static void link_profile_stats(struct tipc_link *l)
753 {
754 	struct sk_buff *skb;
755 	struct tipc_msg *msg;
756 	int length;
757 
758 	/* Update counters used in statistical profiling of send traffic */
759 	l->stats.accu_queue_sz += skb_queue_len(&l->transmq);
760 	l->stats.queue_sz_counts++;
761 
762 	skb = skb_peek(&l->transmq);
763 	if (!skb)
764 		return;
765 	msg = buf_msg(skb);
766 	length = msg_size(msg);
767 
768 	if (msg_user(msg) == MSG_FRAGMENTER) {
769 		if (msg_type(msg) != FIRST_FRAGMENT)
770 			return;
771 		length = msg_size(msg_inner_hdr(msg));
772 	}
773 	l->stats.msg_lengths_total += length;
774 	l->stats.msg_length_counts++;
775 	if (length <= 64)
776 		l->stats.msg_length_profile[0]++;
777 	else if (length <= 256)
778 		l->stats.msg_length_profile[1]++;
779 	else if (length <= 1024)
780 		l->stats.msg_length_profile[2]++;
781 	else if (length <= 4096)
782 		l->stats.msg_length_profile[3]++;
783 	else if (length <= 16384)
784 		l->stats.msg_length_profile[4]++;
785 	else if (length <= 32768)
786 		l->stats.msg_length_profile[5]++;
787 	else
788 		l->stats.msg_length_profile[6]++;
789 }
790 
791 /**
792  * tipc_link_too_silent - check if link is "too silent"
793  * @l: tipc link to be checked
794  *
795  * Returns true if the link 'silent_intv_cnt' is about to reach the
796  * 'abort_limit' value, otherwise false
797  */
798 bool tipc_link_too_silent(struct tipc_link *l)
799 {
800 	return (l->silent_intv_cnt + 2 > l->abort_limit);
801 }
802 
803 /* tipc_link_timeout - perform periodic task as instructed from node timeout
804  */
805 int tipc_link_timeout(struct tipc_link *l, struct sk_buff_head *xmitq)
806 {
807 	int mtyp = 0;
808 	int rc = 0;
809 	bool state = false;
810 	bool probe = false;
811 	bool setup = false;
812 	u16 bc_snt = l->bc_sndlink->snd_nxt - 1;
813 	u16 bc_acked = l->bc_rcvlink->acked;
814 	struct tipc_mon_state *mstate = &l->mon_state;
815 
816 	trace_tipc_link_timeout(l, TIPC_DUMP_NONE, " ");
817 	trace_tipc_link_too_silent(l, TIPC_DUMP_ALL, " ");
818 	switch (l->state) {
819 	case LINK_ESTABLISHED:
820 	case LINK_SYNCHING:
821 		mtyp = STATE_MSG;
822 		link_profile_stats(l);
823 		tipc_mon_get_state(l->net, l->addr, mstate, l->bearer_id);
824 		if (mstate->reset || (l->silent_intv_cnt > l->abort_limit))
825 			return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
826 		state = bc_acked != bc_snt;
827 		state |= l->bc_rcvlink->rcv_unacked;
828 		state |= l->rcv_unacked;
829 		state |= !skb_queue_empty(&l->transmq);
830 		state |= !skb_queue_empty(&l->deferdq);
831 		probe = mstate->probing;
832 		probe |= l->silent_intv_cnt;
833 		if (probe || mstate->monitoring)
834 			l->silent_intv_cnt++;
835 		if (l->snd_nxt == l->checkpoint) {
836 			tipc_link_update_cwin(l, 0, 0);
837 			probe = true;
838 		}
839 		l->checkpoint = l->snd_nxt;
840 		break;
841 	case LINK_RESET:
842 		setup = l->rst_cnt++ <= 4;
843 		setup |= !(l->rst_cnt % 16);
844 		mtyp = RESET_MSG;
845 		break;
846 	case LINK_ESTABLISHING:
847 		setup = true;
848 		mtyp = ACTIVATE_MSG;
849 		break;
850 	case LINK_PEER_RESET:
851 	case LINK_RESETTING:
852 	case LINK_FAILINGOVER:
853 		break;
854 	default:
855 		break;
856 	}
857 
858 	if (state || probe || setup)
859 		tipc_link_build_proto_msg(l, mtyp, probe, 0, 0, 0, 0, xmitq);
860 
861 	return rc;
862 }
863 
864 /**
865  * link_schedule_user - schedule a message sender for wakeup after congestion
866  * @l: congested link
867  * @hdr: header of message that is being sent
868  * Create pseudo msg to send back to user when congestion abates
869  */
870 static int link_schedule_user(struct tipc_link *l, struct tipc_msg *hdr)
871 {
872 	u32 dnode = tipc_own_addr(l->net);
873 	u32 dport = msg_origport(hdr);
874 	struct sk_buff *skb;
875 
876 	/* Create and schedule wakeup pseudo message */
877 	skb = tipc_msg_create(SOCK_WAKEUP, 0, INT_H_SIZE, 0,
878 			      dnode, l->addr, dport, 0, 0);
879 	if (!skb)
880 		return -ENOBUFS;
881 	msg_set_dest_droppable(buf_msg(skb), true);
882 	TIPC_SKB_CB(skb)->chain_imp = msg_importance(hdr);
883 	skb_queue_tail(&l->wakeupq, skb);
884 	l->stats.link_congs++;
885 	trace_tipc_link_conges(l, TIPC_DUMP_ALL, "wakeup scheduled!");
886 	return -ELINKCONG;
887 }
888 
889 /**
890  * link_prepare_wakeup - prepare users for wakeup after congestion
891  * @l: congested link
892  * Wake up a number of waiting users, as permitted by available space
893  * in the send queue
894  */
895 static void link_prepare_wakeup(struct tipc_link *l)
896 {
897 	struct sk_buff_head *wakeupq = &l->wakeupq;
898 	struct sk_buff_head *inputq = l->inputq;
899 	struct sk_buff *skb, *tmp;
900 	struct sk_buff_head tmpq;
901 	int avail[5] = {0,};
902 	int imp = 0;
903 
904 	__skb_queue_head_init(&tmpq);
905 
906 	for (; imp <= TIPC_SYSTEM_IMPORTANCE; imp++)
907 		avail[imp] = l->backlog[imp].limit - l->backlog[imp].len;
908 
909 	skb_queue_walk_safe(wakeupq, skb, tmp) {
910 		imp = TIPC_SKB_CB(skb)->chain_imp;
911 		if (avail[imp] <= 0)
912 			continue;
913 		avail[imp]--;
914 		__skb_unlink(skb, wakeupq);
915 		__skb_queue_tail(&tmpq, skb);
916 	}
917 
918 	spin_lock_bh(&inputq->lock);
919 	skb_queue_splice_tail(&tmpq, inputq);
920 	spin_unlock_bh(&inputq->lock);
921 
922 }
923 
924 void tipc_link_reset(struct tipc_link *l)
925 {
926 	struct sk_buff_head list;
927 	u32 imp;
928 
929 	__skb_queue_head_init(&list);
930 
931 	l->in_session = false;
932 	/* Force re-synch of peer session number before establishing */
933 	l->peer_session--;
934 	l->session++;
935 	l->mtu = l->advertised_mtu;
936 
937 	spin_lock_bh(&l->wakeupq.lock);
938 	skb_queue_splice_init(&l->wakeupq, &list);
939 	spin_unlock_bh(&l->wakeupq.lock);
940 
941 	spin_lock_bh(&l->inputq->lock);
942 	skb_queue_splice_init(&list, l->inputq);
943 	spin_unlock_bh(&l->inputq->lock);
944 
945 	__skb_queue_purge(&l->transmq);
946 	__skb_queue_purge(&l->deferdq);
947 	__skb_queue_purge(&l->backlogq);
948 	__skb_queue_purge(&l->failover_deferdq);
949 	for (imp = 0; imp <= TIPC_SYSTEM_IMPORTANCE; imp++) {
950 		l->backlog[imp].len = 0;
951 		l->backlog[imp].target_bskb = NULL;
952 	}
953 	kfree_skb(l->reasm_buf);
954 	kfree_skb(l->reasm_tnlmsg);
955 	kfree_skb(l->failover_reasm_skb);
956 	l->reasm_buf = NULL;
957 	l->reasm_tnlmsg = NULL;
958 	l->failover_reasm_skb = NULL;
959 	l->rcv_unacked = 0;
960 	l->snd_nxt = 1;
961 	l->rcv_nxt = 1;
962 	l->snd_nxt_state = 1;
963 	l->rcv_nxt_state = 1;
964 	l->acked = 0;
965 	l->last_gap = 0;
966 	kfree(l->last_ga);
967 	l->last_ga = NULL;
968 	l->silent_intv_cnt = 0;
969 	l->rst_cnt = 0;
970 	l->bc_peer_is_up = false;
971 	memset(&l->mon_state, 0, sizeof(l->mon_state));
972 	tipc_link_reset_stats(l);
973 }
974 
975 /**
976  * tipc_link_xmit(): enqueue buffer list according to queue situation
977  * @link: link to use
978  * @list: chain of buffers containing message
979  * @xmitq: returned list of packets to be sent by caller
980  *
981  * Consumes the buffer chain.
982  * Returns 0 if success, or errno: -ELINKCONG, -EMSGSIZE or -ENOBUFS
983  * Messages at TIPC_SYSTEM_IMPORTANCE are always accepted
984  */
985 int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *list,
986 		   struct sk_buff_head *xmitq)
987 {
988 	struct tipc_msg *hdr = buf_msg(skb_peek(list));
989 	struct sk_buff_head *backlogq = &l->backlogq;
990 	struct sk_buff_head *transmq = &l->transmq;
991 	struct sk_buff *skb, *_skb;
992 	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
993 	u16 ack = l->rcv_nxt - 1;
994 	u16 seqno = l->snd_nxt;
995 	int pkt_cnt = skb_queue_len(list);
996 	int imp = msg_importance(hdr);
997 	unsigned int mss = tipc_link_mss(l);
998 	unsigned int cwin = l->window;
999 	unsigned int mtu = l->mtu;
1000 	bool new_bundle;
1001 	int rc = 0;
1002 
1003 	if (unlikely(msg_size(hdr) > mtu)) {
1004 		pr_warn("Too large msg, purging xmit list %d %d %d %d %d!\n",
1005 			skb_queue_len(list), msg_user(hdr),
1006 			msg_type(hdr), msg_size(hdr), mtu);
1007 		__skb_queue_purge(list);
1008 		return -EMSGSIZE;
1009 	}
1010 
1011 	/* Allow oversubscription of one data msg per source at congestion */
1012 	if (unlikely(l->backlog[imp].len >= l->backlog[imp].limit)) {
1013 		if (imp == TIPC_SYSTEM_IMPORTANCE) {
1014 			pr_warn("%s<%s>, link overflow", link_rst_msg, l->name);
1015 			return -ENOBUFS;
1016 		}
1017 		rc = link_schedule_user(l, hdr);
1018 	}
1019 
1020 	if (pkt_cnt > 1) {
1021 		l->stats.sent_fragmented++;
1022 		l->stats.sent_fragments += pkt_cnt;
1023 	}
1024 
1025 	/* Prepare each packet for sending, and add to relevant queue: */
1026 	while ((skb = __skb_dequeue(list))) {
1027 		if (likely(skb_queue_len(transmq) < cwin)) {
1028 			hdr = buf_msg(skb);
1029 			msg_set_seqno(hdr, seqno);
1030 			msg_set_ack(hdr, ack);
1031 			msg_set_bcast_ack(hdr, bc_ack);
1032 			_skb = skb_clone(skb, GFP_ATOMIC);
1033 			if (!_skb) {
1034 				kfree_skb(skb);
1035 				__skb_queue_purge(list);
1036 				return -ENOBUFS;
1037 			}
1038 			__skb_queue_tail(transmq, skb);
1039 			/* next retransmit attempt */
1040 			if (link_is_bc_sndlink(l))
1041 				TIPC_SKB_CB(skb)->nxt_retr = TIPC_BC_RETR_LIM;
1042 			__skb_queue_tail(xmitq, _skb);
1043 			TIPC_SKB_CB(skb)->ackers = l->ackers;
1044 			l->rcv_unacked = 0;
1045 			l->stats.sent_pkts++;
1046 			seqno++;
1047 			continue;
1048 		}
1049 		if (tipc_msg_try_bundle(l->backlog[imp].target_bskb, &skb,
1050 					mss, l->addr, &new_bundle)) {
1051 			if (skb) {
1052 				/* Keep a ref. to the skb for next try */
1053 				l->backlog[imp].target_bskb = skb;
1054 				l->backlog[imp].len++;
1055 				__skb_queue_tail(backlogq, skb);
1056 			} else {
1057 				if (new_bundle) {
1058 					l->stats.sent_bundles++;
1059 					l->stats.sent_bundled++;
1060 				}
1061 				l->stats.sent_bundled++;
1062 			}
1063 			continue;
1064 		}
1065 		l->backlog[imp].target_bskb = NULL;
1066 		l->backlog[imp].len += (1 + skb_queue_len(list));
1067 		__skb_queue_tail(backlogq, skb);
1068 		skb_queue_splice_tail_init(list, backlogq);
1069 	}
1070 	l->snd_nxt = seqno;
1071 	return rc;
1072 }
1073 
1074 static void tipc_link_update_cwin(struct tipc_link *l, int released,
1075 				  bool retransmitted)
1076 {
1077 	int bklog_len = skb_queue_len(&l->backlogq);
1078 	struct sk_buff_head *txq = &l->transmq;
1079 	int txq_len = skb_queue_len(txq);
1080 	u16 cwin = l->window;
1081 
1082 	/* Enter fast recovery */
1083 	if (unlikely(retransmitted)) {
1084 		l->ssthresh = max_t(u16, l->window / 2, 300);
1085 		l->window = min_t(u16, l->ssthresh, l->window);
1086 		return;
1087 	}
1088 	/* Enter slow start */
1089 	if (unlikely(!released)) {
1090 		l->ssthresh = max_t(u16, l->window / 2, 300);
1091 		l->window = l->min_win;
1092 		return;
1093 	}
1094 	/* Don't increase window if no pressure on the transmit queue */
1095 	if (txq_len + bklog_len < cwin)
1096 		return;
1097 
1098 	/* Don't increase window if there are holes the transmit queue */
1099 	if (txq_len && l->snd_nxt - buf_seqno(skb_peek(txq)) != txq_len)
1100 		return;
1101 
1102 	l->cong_acks += released;
1103 
1104 	/* Slow start  */
1105 	if (cwin <= l->ssthresh) {
1106 		l->window = min_t(u16, cwin + released, l->max_win);
1107 		return;
1108 	}
1109 	/* Congestion avoidance */
1110 	if (l->cong_acks < cwin)
1111 		return;
1112 	l->window = min_t(u16, ++cwin, l->max_win);
1113 	l->cong_acks = 0;
1114 }
1115 
1116 static void tipc_link_advance_backlog(struct tipc_link *l,
1117 				      struct sk_buff_head *xmitq)
1118 {
1119 	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
1120 	struct sk_buff_head *txq = &l->transmq;
1121 	struct sk_buff *skb, *_skb;
1122 	u16 ack = l->rcv_nxt - 1;
1123 	u16 seqno = l->snd_nxt;
1124 	struct tipc_msg *hdr;
1125 	u16 cwin = l->window;
1126 	u32 imp;
1127 
1128 	while (skb_queue_len(txq) < cwin) {
1129 		skb = skb_peek(&l->backlogq);
1130 		if (!skb)
1131 			break;
1132 		_skb = skb_clone(skb, GFP_ATOMIC);
1133 		if (!_skb)
1134 			break;
1135 		__skb_dequeue(&l->backlogq);
1136 		hdr = buf_msg(skb);
1137 		imp = msg_importance(hdr);
1138 		l->backlog[imp].len--;
1139 		if (unlikely(skb == l->backlog[imp].target_bskb))
1140 			l->backlog[imp].target_bskb = NULL;
1141 		__skb_queue_tail(&l->transmq, skb);
1142 		/* next retransmit attempt */
1143 		if (link_is_bc_sndlink(l))
1144 			TIPC_SKB_CB(skb)->nxt_retr = TIPC_BC_RETR_LIM;
1145 
1146 		__skb_queue_tail(xmitq, _skb);
1147 		TIPC_SKB_CB(skb)->ackers = l->ackers;
1148 		msg_set_seqno(hdr, seqno);
1149 		msg_set_ack(hdr, ack);
1150 		msg_set_bcast_ack(hdr, bc_ack);
1151 		l->rcv_unacked = 0;
1152 		l->stats.sent_pkts++;
1153 		seqno++;
1154 	}
1155 	l->snd_nxt = seqno;
1156 }
1157 
1158 /**
1159  * link_retransmit_failure() - Detect repeated retransmit failures
1160  * @l: tipc link sender
1161  * @r: tipc link receiver (= l in case of unicast)
1162  * @rc: returned code
1163  *
1164  * Return: true if the repeated retransmit failures happens, otherwise
1165  * false
1166  */
1167 static bool link_retransmit_failure(struct tipc_link *l, struct tipc_link *r,
1168 				    int *rc)
1169 {
1170 	struct sk_buff *skb = skb_peek(&l->transmq);
1171 	struct tipc_msg *hdr;
1172 
1173 	if (!skb)
1174 		return false;
1175 
1176 	if (!TIPC_SKB_CB(skb)->retr_cnt)
1177 		return false;
1178 
1179 	if (!time_after(jiffies, TIPC_SKB_CB(skb)->retr_stamp +
1180 			msecs_to_jiffies(r->tolerance * 10)))
1181 		return false;
1182 
1183 	hdr = buf_msg(skb);
1184 	if (link_is_bc_sndlink(l) && !less(r->acked, msg_seqno(hdr)))
1185 		return false;
1186 
1187 	pr_warn("Retransmission failure on link <%s>\n", l->name);
1188 	link_print(l, "State of link ");
1189 	pr_info("Failed msg: usr %u, typ %u, len %u, err %u\n",
1190 		msg_user(hdr), msg_type(hdr), msg_size(hdr), msg_errcode(hdr));
1191 	pr_info("sqno %u, prev: %x, dest: %x\n",
1192 		msg_seqno(hdr), msg_prevnode(hdr), msg_destnode(hdr));
1193 	pr_info("retr_stamp %d, retr_cnt %d\n",
1194 		jiffies_to_msecs(TIPC_SKB_CB(skb)->retr_stamp),
1195 		TIPC_SKB_CB(skb)->retr_cnt);
1196 
1197 	trace_tipc_list_dump(&l->transmq, true, "retrans failure!");
1198 	trace_tipc_link_dump(l, TIPC_DUMP_NONE, "retrans failure!");
1199 	trace_tipc_link_dump(r, TIPC_DUMP_NONE, "retrans failure!");
1200 
1201 	if (link_is_bc_sndlink(l)) {
1202 		r->state = LINK_RESET;
1203 		*rc |= TIPC_LINK_DOWN_EVT;
1204 	} else {
1205 		*rc |= tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1206 	}
1207 
1208 	return true;
1209 }
1210 
1211 /* tipc_data_input - deliver data and name distr msgs to upper layer
1212  *
1213  * Consumes buffer if message is of right type
1214  * Node lock must be held
1215  */
1216 static bool tipc_data_input(struct tipc_link *l, struct sk_buff *skb,
1217 			    struct sk_buff_head *inputq)
1218 {
1219 	struct sk_buff_head *mc_inputq = l->bc_rcvlink->inputq;
1220 	struct tipc_msg *hdr = buf_msg(skb);
1221 
1222 	switch (msg_user(hdr)) {
1223 	case TIPC_LOW_IMPORTANCE:
1224 	case TIPC_MEDIUM_IMPORTANCE:
1225 	case TIPC_HIGH_IMPORTANCE:
1226 	case TIPC_CRITICAL_IMPORTANCE:
1227 		if (unlikely(msg_in_group(hdr) || msg_mcast(hdr))) {
1228 			skb_queue_tail(mc_inputq, skb);
1229 			return true;
1230 		}
1231 		/* fall through */
1232 	case CONN_MANAGER:
1233 		skb_queue_tail(inputq, skb);
1234 		return true;
1235 	case GROUP_PROTOCOL:
1236 		skb_queue_tail(mc_inputq, skb);
1237 		return true;
1238 	case NAME_DISTRIBUTOR:
1239 		l->bc_rcvlink->state = LINK_ESTABLISHED;
1240 		skb_queue_tail(l->namedq, skb);
1241 		return true;
1242 	case MSG_BUNDLER:
1243 	case TUNNEL_PROTOCOL:
1244 	case MSG_FRAGMENTER:
1245 	case BCAST_PROTOCOL:
1246 		return false;
1247 	default:
1248 		pr_warn("Dropping received illegal msg type\n");
1249 		kfree_skb(skb);
1250 		return true;
1251 	};
1252 }
1253 
1254 /* tipc_link_input - process packet that has passed link protocol check
1255  *
1256  * Consumes buffer
1257  */
1258 static int tipc_link_input(struct tipc_link *l, struct sk_buff *skb,
1259 			   struct sk_buff_head *inputq,
1260 			   struct sk_buff **reasm_skb)
1261 {
1262 	struct tipc_msg *hdr = buf_msg(skb);
1263 	struct sk_buff *iskb;
1264 	struct sk_buff_head tmpq;
1265 	int usr = msg_user(hdr);
1266 	int pos = 0;
1267 
1268 	if (usr == MSG_BUNDLER) {
1269 		skb_queue_head_init(&tmpq);
1270 		l->stats.recv_bundles++;
1271 		l->stats.recv_bundled += msg_msgcnt(hdr);
1272 		while (tipc_msg_extract(skb, &iskb, &pos))
1273 			tipc_data_input(l, iskb, &tmpq);
1274 		tipc_skb_queue_splice_tail(&tmpq, inputq);
1275 		return 0;
1276 	} else if (usr == MSG_FRAGMENTER) {
1277 		l->stats.recv_fragments++;
1278 		if (tipc_buf_append(reasm_skb, &skb)) {
1279 			l->stats.recv_fragmented++;
1280 			tipc_data_input(l, skb, inputq);
1281 		} else if (!*reasm_skb && !link_is_bc_rcvlink(l)) {
1282 			pr_warn_ratelimited("Unable to build fragment list\n");
1283 			return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1284 		}
1285 		return 0;
1286 	} else if (usr == BCAST_PROTOCOL) {
1287 		tipc_bcast_lock(l->net);
1288 		tipc_link_bc_init_rcv(l->bc_rcvlink, hdr);
1289 		tipc_bcast_unlock(l->net);
1290 	}
1291 
1292 	kfree_skb(skb);
1293 	return 0;
1294 }
1295 
1296 /* tipc_link_tnl_rcv() - receive TUNNEL_PROTOCOL message, drop or process the
1297  *			 inner message along with the ones in the old link's
1298  *			 deferdq
1299  * @l: tunnel link
1300  * @skb: TUNNEL_PROTOCOL message
1301  * @inputq: queue to put messages ready for delivery
1302  */
1303 static int tipc_link_tnl_rcv(struct tipc_link *l, struct sk_buff *skb,
1304 			     struct sk_buff_head *inputq)
1305 {
1306 	struct sk_buff **reasm_skb = &l->failover_reasm_skb;
1307 	struct sk_buff **reasm_tnlmsg = &l->reasm_tnlmsg;
1308 	struct sk_buff_head *fdefq = &l->failover_deferdq;
1309 	struct tipc_msg *hdr = buf_msg(skb);
1310 	struct sk_buff *iskb;
1311 	int ipos = 0;
1312 	int rc = 0;
1313 	u16 seqno;
1314 
1315 	if (msg_type(hdr) == SYNCH_MSG) {
1316 		kfree_skb(skb);
1317 		return 0;
1318 	}
1319 
1320 	/* Not a fragment? */
1321 	if (likely(!msg_nof_fragms(hdr))) {
1322 		if (unlikely(!tipc_msg_extract(skb, &iskb, &ipos))) {
1323 			pr_warn_ratelimited("Unable to extract msg, defq: %d\n",
1324 					    skb_queue_len(fdefq));
1325 			return 0;
1326 		}
1327 		kfree_skb(skb);
1328 	} else {
1329 		/* Set fragment type for buf_append */
1330 		if (msg_fragm_no(hdr) == 1)
1331 			msg_set_type(hdr, FIRST_FRAGMENT);
1332 		else if (msg_fragm_no(hdr) < msg_nof_fragms(hdr))
1333 			msg_set_type(hdr, FRAGMENT);
1334 		else
1335 			msg_set_type(hdr, LAST_FRAGMENT);
1336 
1337 		if (!tipc_buf_append(reasm_tnlmsg, &skb)) {
1338 			/* Successful but non-complete reassembly? */
1339 			if (*reasm_tnlmsg || link_is_bc_rcvlink(l))
1340 				return 0;
1341 			pr_warn_ratelimited("Unable to reassemble tunnel msg\n");
1342 			return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1343 		}
1344 		iskb = skb;
1345 	}
1346 
1347 	do {
1348 		seqno = buf_seqno(iskb);
1349 		if (unlikely(less(seqno, l->drop_point))) {
1350 			kfree_skb(iskb);
1351 			continue;
1352 		}
1353 		if (unlikely(seqno != l->drop_point)) {
1354 			__tipc_skb_queue_sorted(fdefq, seqno, iskb);
1355 			continue;
1356 		}
1357 
1358 		l->drop_point++;
1359 		if (!tipc_data_input(l, iskb, inputq))
1360 			rc |= tipc_link_input(l, iskb, inputq, reasm_skb);
1361 		if (unlikely(rc))
1362 			break;
1363 	} while ((iskb = __tipc_skb_dequeue(fdefq, l->drop_point)));
1364 
1365 	return rc;
1366 }
1367 
1368 /**
1369  * tipc_get_gap_ack_blks - get Gap ACK blocks from PROTOCOL/STATE_MSG
1370  * @ga: returned pointer to the Gap ACK blocks if any
1371  * @l: the tipc link
1372  * @hdr: the PROTOCOL/STATE_MSG header
1373  * @uc: desired Gap ACK blocks type, i.e. unicast (= 1) or broadcast (= 0)
1374  *
1375  * Return: the total Gap ACK blocks size
1376  */
1377 u16 tipc_get_gap_ack_blks(struct tipc_gap_ack_blks **ga, struct tipc_link *l,
1378 			  struct tipc_msg *hdr, bool uc)
1379 {
1380 	struct tipc_gap_ack_blks *p;
1381 	u16 sz = 0;
1382 
1383 	/* Does peer support the Gap ACK blocks feature? */
1384 	if (l->peer_caps & TIPC_GAP_ACK_BLOCK) {
1385 		p = (struct tipc_gap_ack_blks *)msg_data(hdr);
1386 		sz = ntohs(p->len);
1387 		/* Sanity check */
1388 		if (sz == tipc_gap_ack_blks_sz(p->ugack_cnt + p->bgack_cnt)) {
1389 			/* Good, check if the desired type exists */
1390 			if ((uc && p->ugack_cnt) || (!uc && p->bgack_cnt))
1391 				goto ok;
1392 		/* Backward compatible: peer might not support bc, but uc? */
1393 		} else if (uc && sz == tipc_gap_ack_blks_sz(p->ugack_cnt)) {
1394 			if (p->ugack_cnt) {
1395 				p->bgack_cnt = 0;
1396 				goto ok;
1397 			}
1398 		}
1399 	}
1400 	/* Other cases: ignore! */
1401 	p = NULL;
1402 
1403 ok:
1404 	*ga = p;
1405 	return sz;
1406 }
1407 
1408 static u8 __tipc_build_gap_ack_blks(struct tipc_gap_ack_blks *ga,
1409 				    struct tipc_link *l, u8 start_index)
1410 {
1411 	struct tipc_gap_ack *gacks = &ga->gacks[start_index];
1412 	struct sk_buff *skb = skb_peek(&l->deferdq);
1413 	u16 expect, seqno = 0;
1414 	u8 n = 0;
1415 
1416 	if (!skb)
1417 		return 0;
1418 
1419 	expect = buf_seqno(skb);
1420 	skb_queue_walk(&l->deferdq, skb) {
1421 		seqno = buf_seqno(skb);
1422 		if (unlikely(more(seqno, expect))) {
1423 			gacks[n].ack = htons(expect - 1);
1424 			gacks[n].gap = htons(seqno - expect);
1425 			if (++n >= MAX_GAP_ACK_BLKS / 2) {
1426 				pr_info_ratelimited("Gacks on %s: %d, ql: %d!\n",
1427 						    l->name, n,
1428 						    skb_queue_len(&l->deferdq));
1429 				return n;
1430 			}
1431 		} else if (unlikely(less(seqno, expect))) {
1432 			pr_warn("Unexpected skb in deferdq!\n");
1433 			continue;
1434 		}
1435 		expect = seqno + 1;
1436 	}
1437 
1438 	/* last block */
1439 	gacks[n].ack = htons(seqno);
1440 	gacks[n].gap = 0;
1441 	n++;
1442 	return n;
1443 }
1444 
1445 /* tipc_build_gap_ack_blks - build Gap ACK blocks
1446  * @l: tipc unicast link
1447  * @hdr: the tipc message buffer to store the Gap ACK blocks after built
1448  *
1449  * The function builds Gap ACK blocks for both the unicast & broadcast receiver
1450  * links of a certain peer, the buffer after built has the network data format
1451  * as found at the struct tipc_gap_ack_blks definition.
1452  *
1453  * returns the actual allocated memory size
1454  */
1455 static u16 tipc_build_gap_ack_blks(struct tipc_link *l, struct tipc_msg *hdr)
1456 {
1457 	struct tipc_link *bcl = l->bc_rcvlink;
1458 	struct tipc_gap_ack_blks *ga;
1459 	u16 len;
1460 
1461 	ga = (struct tipc_gap_ack_blks *)msg_data(hdr);
1462 
1463 	/* Start with broadcast link first */
1464 	tipc_bcast_lock(bcl->net);
1465 	msg_set_bcast_ack(hdr, bcl->rcv_nxt - 1);
1466 	msg_set_bc_gap(hdr, link_bc_rcv_gap(bcl));
1467 	ga->bgack_cnt = __tipc_build_gap_ack_blks(ga, bcl, 0);
1468 	tipc_bcast_unlock(bcl->net);
1469 
1470 	/* Now for unicast link, but an explicit NACK only (???) */
1471 	ga->ugack_cnt = (msg_seq_gap(hdr)) ?
1472 			__tipc_build_gap_ack_blks(ga, l, ga->bgack_cnt) : 0;
1473 
1474 	/* Total len */
1475 	len = tipc_gap_ack_blks_sz(ga->bgack_cnt + ga->ugack_cnt);
1476 	ga->len = htons(len);
1477 	return len;
1478 }
1479 
1480 /* tipc_link_advance_transmq - advance TIPC link transmq queue by releasing
1481  *			       acked packets, also doing retransmissions if
1482  *			       gaps found
1483  * @l: tipc link with transmq queue to be advanced
1484  * @r: tipc link "receiver" i.e. in case of broadcast (= "l" if unicast)
1485  * @acked: seqno of last packet acked by peer without any gaps before
1486  * @gap: # of gap packets
1487  * @ga: buffer pointer to Gap ACK blocks from peer
1488  * @xmitq: queue for accumulating the retransmitted packets if any
1489  * @retransmitted: returned boolean value if a retransmission is really issued
1490  * @rc: returned code e.g. TIPC_LINK_DOWN_EVT if a repeated retransmit failures
1491  *      happens (- unlikely case)
1492  *
1493  * Return: the number of packets released from the link transmq
1494  */
1495 static int tipc_link_advance_transmq(struct tipc_link *l, struct tipc_link *r,
1496 				     u16 acked, u16 gap,
1497 				     struct tipc_gap_ack_blks *ga,
1498 				     struct sk_buff_head *xmitq,
1499 				     bool *retransmitted, int *rc)
1500 {
1501 	struct tipc_gap_ack_blks *last_ga = r->last_ga, *this_ga = NULL;
1502 	struct tipc_gap_ack *gacks = NULL;
1503 	struct sk_buff *skb, *_skb, *tmp;
1504 	struct tipc_msg *hdr;
1505 	u32 qlen = skb_queue_len(&l->transmq);
1506 	u16 nacked = acked, ngap = gap, gack_cnt = 0;
1507 	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
1508 	u16 ack = l->rcv_nxt - 1;
1509 	u16 seqno, n = 0;
1510 	u16 end = r->acked, start = end, offset = r->last_gap;
1511 	u16 si = (last_ga) ? last_ga->start_index : 0;
1512 	bool is_uc = !link_is_bc_sndlink(l);
1513 	bool bc_has_acked = false;
1514 
1515 	trace_tipc_link_retrans(r, acked + 1, acked + gap, &l->transmq);
1516 
1517 	/* Determine Gap ACK blocks if any for the particular link */
1518 	if (ga && is_uc) {
1519 		/* Get the Gap ACKs, uc part */
1520 		gack_cnt = ga->ugack_cnt;
1521 		gacks = &ga->gacks[ga->bgack_cnt];
1522 	} else if (ga) {
1523 		/* Copy the Gap ACKs, bc part, for later renewal if needed */
1524 		this_ga = kmemdup(ga, tipc_gap_ack_blks_sz(ga->bgack_cnt),
1525 				  GFP_ATOMIC);
1526 		if (likely(this_ga)) {
1527 			this_ga->start_index = 0;
1528 			/* Start with the bc Gap ACKs */
1529 			gack_cnt = this_ga->bgack_cnt;
1530 			gacks = &this_ga->gacks[0];
1531 		} else {
1532 			/* Hmm, we can get in trouble..., simply ignore it */
1533 			pr_warn_ratelimited("Ignoring bc Gap ACKs, no memory\n");
1534 		}
1535 	}
1536 
1537 	/* Advance the link transmq */
1538 	skb_queue_walk_safe(&l->transmq, skb, tmp) {
1539 		seqno = buf_seqno(skb);
1540 
1541 next_gap_ack:
1542 		if (less_eq(seqno, nacked)) {
1543 			if (is_uc)
1544 				goto release;
1545 			/* Skip packets peer has already acked */
1546 			if (!more(seqno, r->acked))
1547 				continue;
1548 			/* Get the next of last Gap ACK blocks */
1549 			while (more(seqno, end)) {
1550 				if (!last_ga || si >= last_ga->bgack_cnt)
1551 					break;
1552 				start = end + offset + 1;
1553 				end = ntohs(last_ga->gacks[si].ack);
1554 				offset = ntohs(last_ga->gacks[si].gap);
1555 				si++;
1556 				WARN_ONCE(more(start, end) ||
1557 					  (!offset &&
1558 					   si < last_ga->bgack_cnt) ||
1559 					  si > MAX_GAP_ACK_BLKS,
1560 					  "Corrupted Gap ACK: %d %d %d %d %d\n",
1561 					  start, end, offset, si,
1562 					  last_ga->bgack_cnt);
1563 			}
1564 			/* Check against the last Gap ACK block */
1565 			if (in_range(seqno, start, end))
1566 				continue;
1567 			/* Update/release the packet peer is acking */
1568 			bc_has_acked = true;
1569 			if (--TIPC_SKB_CB(skb)->ackers)
1570 				continue;
1571 release:
1572 			/* release skb */
1573 			__skb_unlink(skb, &l->transmq);
1574 			kfree_skb(skb);
1575 		} else if (less_eq(seqno, nacked + ngap)) {
1576 			/* First gap: check if repeated retrans failures? */
1577 			if (unlikely(seqno == acked + 1 &&
1578 				     link_retransmit_failure(l, r, rc))) {
1579 				/* Ignore this bc Gap ACKs if any */
1580 				kfree(this_ga);
1581 				this_ga = NULL;
1582 				break;
1583 			}
1584 			/* retransmit skb if unrestricted*/
1585 			if (time_before(jiffies, TIPC_SKB_CB(skb)->nxt_retr))
1586 				continue;
1587 			TIPC_SKB_CB(skb)->nxt_retr = (is_uc) ?
1588 					TIPC_UC_RETR_TIME : TIPC_BC_RETR_LIM;
1589 			_skb = pskb_copy(skb, GFP_ATOMIC);
1590 			if (!_skb)
1591 				continue;
1592 			hdr = buf_msg(_skb);
1593 			msg_set_ack(hdr, ack);
1594 			msg_set_bcast_ack(hdr, bc_ack);
1595 			_skb->priority = TC_PRIO_CONTROL;
1596 			__skb_queue_tail(xmitq, _skb);
1597 			l->stats.retransmitted++;
1598 			if (!is_uc)
1599 				r->stats.retransmitted++;
1600 			*retransmitted = true;
1601 			/* Increase actual retrans counter & mark first time */
1602 			if (!TIPC_SKB_CB(skb)->retr_cnt++)
1603 				TIPC_SKB_CB(skb)->retr_stamp = jiffies;
1604 		} else {
1605 			/* retry with Gap ACK blocks if any */
1606 			if (n >= gack_cnt)
1607 				break;
1608 			nacked = ntohs(gacks[n].ack);
1609 			ngap = ntohs(gacks[n].gap);
1610 			n++;
1611 			goto next_gap_ack;
1612 		}
1613 	}
1614 
1615 	/* Renew last Gap ACK blocks for bc if needed */
1616 	if (bc_has_acked) {
1617 		if (this_ga) {
1618 			kfree(last_ga);
1619 			r->last_ga = this_ga;
1620 			r->last_gap = gap;
1621 		} else if (last_ga) {
1622 			if (less(acked, start)) {
1623 				si--;
1624 				offset = start - acked - 1;
1625 			} else if (less(acked, end)) {
1626 				acked = end;
1627 			}
1628 			if (si < last_ga->bgack_cnt) {
1629 				last_ga->start_index = si;
1630 				r->last_gap = offset;
1631 			} else {
1632 				kfree(last_ga);
1633 				r->last_ga = NULL;
1634 				r->last_gap = 0;
1635 			}
1636 		} else {
1637 			r->last_gap = 0;
1638 		}
1639 		r->acked = acked;
1640 	} else {
1641 		kfree(this_ga);
1642 	}
1643 
1644 	return qlen - skb_queue_len(&l->transmq);
1645 }
1646 
1647 /* tipc_link_build_state_msg: prepare link state message for transmission
1648  *
1649  * Note that sending of broadcast ack is coordinated among nodes, to reduce
1650  * risk of ack storms towards the sender
1651  */
1652 int tipc_link_build_state_msg(struct tipc_link *l, struct sk_buff_head *xmitq)
1653 {
1654 	if (!l)
1655 		return 0;
1656 
1657 	/* Broadcast ACK must be sent via a unicast link => defer to caller */
1658 	if (link_is_bc_rcvlink(l)) {
1659 		if (((l->rcv_nxt ^ tipc_own_addr(l->net)) & 0xf) != 0xf)
1660 			return 0;
1661 		l->rcv_unacked = 0;
1662 
1663 		/* Use snd_nxt to store peer's snd_nxt in broadcast rcv link */
1664 		l->snd_nxt = l->rcv_nxt;
1665 		return TIPC_LINK_SND_STATE;
1666 	}
1667 	/* Unicast ACK */
1668 	l->rcv_unacked = 0;
1669 	l->stats.sent_acks++;
1670 	tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, 0, 0, xmitq);
1671 	return 0;
1672 }
1673 
1674 /* tipc_link_build_reset_msg: prepare link RESET or ACTIVATE message
1675  */
1676 void tipc_link_build_reset_msg(struct tipc_link *l, struct sk_buff_head *xmitq)
1677 {
1678 	int mtyp = RESET_MSG;
1679 	struct sk_buff *skb;
1680 
1681 	if (l->state == LINK_ESTABLISHING)
1682 		mtyp = ACTIVATE_MSG;
1683 
1684 	tipc_link_build_proto_msg(l, mtyp, 0, 0, 0, 0, 0, xmitq);
1685 
1686 	/* Inform peer that this endpoint is going down if applicable */
1687 	skb = skb_peek_tail(xmitq);
1688 	if (skb && (l->state == LINK_RESET))
1689 		msg_set_peer_stopping(buf_msg(skb), 1);
1690 }
1691 
1692 /* tipc_link_build_nack_msg: prepare link nack message for transmission
1693  * Note that sending of broadcast NACK is coordinated among nodes, to
1694  * reduce the risk of NACK storms towards the sender
1695  */
1696 static int tipc_link_build_nack_msg(struct tipc_link *l,
1697 				    struct sk_buff_head *xmitq)
1698 {
1699 	u32 def_cnt = ++l->stats.deferred_recv;
1700 	struct sk_buff_head *dfq = &l->deferdq;
1701 	u32 defq_len = skb_queue_len(dfq);
1702 	int match1, match2;
1703 
1704 	if (link_is_bc_rcvlink(l)) {
1705 		match1 = def_cnt & 0xf;
1706 		match2 = tipc_own_addr(l->net) & 0xf;
1707 		if (match1 == match2)
1708 			return TIPC_LINK_SND_STATE;
1709 		return 0;
1710 	}
1711 
1712 	if (defq_len >= 3 && !((defq_len - 3) % 16)) {
1713 		u16 rcvgap = buf_seqno(skb_peek(dfq)) - l->rcv_nxt;
1714 
1715 		tipc_link_build_proto_msg(l, STATE_MSG, 0, 0,
1716 					  rcvgap, 0, 0, xmitq);
1717 	}
1718 	return 0;
1719 }
1720 
1721 /* tipc_link_rcv - process TIPC packets/messages arriving from off-node
1722  * @l: the link that should handle the message
1723  * @skb: TIPC packet
1724  * @xmitq: queue to place packets to be sent after this call
1725  */
1726 int tipc_link_rcv(struct tipc_link *l, struct sk_buff *skb,
1727 		  struct sk_buff_head *xmitq)
1728 {
1729 	struct sk_buff_head *defq = &l->deferdq;
1730 	struct tipc_msg *hdr = buf_msg(skb);
1731 	u16 seqno, rcv_nxt, win_lim;
1732 	int released = 0;
1733 	int rc = 0;
1734 
1735 	/* Verify and update link state */
1736 	if (unlikely(msg_user(hdr) == LINK_PROTOCOL))
1737 		return tipc_link_proto_rcv(l, skb, xmitq);
1738 
1739 	/* Don't send probe at next timeout expiration */
1740 	l->silent_intv_cnt = 0;
1741 
1742 	do {
1743 		hdr = buf_msg(skb);
1744 		seqno = msg_seqno(hdr);
1745 		rcv_nxt = l->rcv_nxt;
1746 		win_lim = rcv_nxt + TIPC_MAX_LINK_WIN;
1747 
1748 		if (unlikely(!link_is_up(l))) {
1749 			if (l->state == LINK_ESTABLISHING)
1750 				rc = TIPC_LINK_UP_EVT;
1751 			kfree_skb(skb);
1752 			break;
1753 		}
1754 
1755 		/* Drop if outside receive window */
1756 		if (unlikely(less(seqno, rcv_nxt) || more(seqno, win_lim))) {
1757 			l->stats.duplicates++;
1758 			kfree_skb(skb);
1759 			break;
1760 		}
1761 		released += tipc_link_advance_transmq(l, l, msg_ack(hdr), 0,
1762 						      NULL, NULL, NULL, NULL);
1763 
1764 		/* Defer delivery if sequence gap */
1765 		if (unlikely(seqno != rcv_nxt)) {
1766 			if (!__tipc_skb_queue_sorted(defq, seqno, skb))
1767 				l->stats.duplicates++;
1768 			rc |= tipc_link_build_nack_msg(l, xmitq);
1769 			break;
1770 		}
1771 
1772 		/* Deliver packet */
1773 		l->rcv_nxt++;
1774 		l->stats.recv_pkts++;
1775 
1776 		if (unlikely(msg_user(hdr) == TUNNEL_PROTOCOL))
1777 			rc |= tipc_link_tnl_rcv(l, skb, l->inputq);
1778 		else if (!tipc_data_input(l, skb, l->inputq))
1779 			rc |= tipc_link_input(l, skb, l->inputq, &l->reasm_buf);
1780 		if (unlikely(++l->rcv_unacked >= TIPC_MIN_LINK_WIN))
1781 			rc |= tipc_link_build_state_msg(l, xmitq);
1782 		if (unlikely(rc & ~TIPC_LINK_SND_STATE))
1783 			break;
1784 	} while ((skb = __tipc_skb_dequeue(defq, l->rcv_nxt)));
1785 
1786 	/* Forward queues and wake up waiting users */
1787 	if (released) {
1788 		tipc_link_update_cwin(l, released, 0);
1789 		tipc_link_advance_backlog(l, xmitq);
1790 		if (unlikely(!skb_queue_empty(&l->wakeupq)))
1791 			link_prepare_wakeup(l);
1792 	}
1793 	return rc;
1794 }
1795 
1796 static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
1797 				      bool probe_reply, u16 rcvgap,
1798 				      int tolerance, int priority,
1799 				      struct sk_buff_head *xmitq)
1800 {
1801 	struct tipc_mon_state *mstate = &l->mon_state;
1802 	struct sk_buff_head *dfq = &l->deferdq;
1803 	struct tipc_link *bcl = l->bc_rcvlink;
1804 	struct tipc_msg *hdr;
1805 	struct sk_buff *skb;
1806 	bool node_up = link_is_up(bcl);
1807 	u16 glen = 0, bc_rcvgap = 0;
1808 	int dlen = 0;
1809 	void *data;
1810 
1811 	/* Don't send protocol message during reset or link failover */
1812 	if (tipc_link_is_blocked(l))
1813 		return;
1814 
1815 	if (!tipc_link_is_up(l) && (mtyp == STATE_MSG))
1816 		return;
1817 
1818 	if ((probe || probe_reply) && !skb_queue_empty(dfq))
1819 		rcvgap = buf_seqno(skb_peek(dfq)) - l->rcv_nxt;
1820 
1821 	skb = tipc_msg_create(LINK_PROTOCOL, mtyp, INT_H_SIZE,
1822 			      tipc_max_domain_size + MAX_GAP_ACK_BLKS_SZ,
1823 			      l->addr, tipc_own_addr(l->net), 0, 0, 0);
1824 	if (!skb)
1825 		return;
1826 
1827 	hdr = buf_msg(skb);
1828 	data = msg_data(hdr);
1829 	msg_set_session(hdr, l->session);
1830 	msg_set_bearer_id(hdr, l->bearer_id);
1831 	msg_set_net_plane(hdr, l->net_plane);
1832 	msg_set_next_sent(hdr, l->snd_nxt);
1833 	msg_set_ack(hdr, l->rcv_nxt - 1);
1834 	msg_set_bcast_ack(hdr, bcl->rcv_nxt - 1);
1835 	msg_set_bc_ack_invalid(hdr, !node_up);
1836 	msg_set_last_bcast(hdr, l->bc_sndlink->snd_nxt - 1);
1837 	msg_set_link_tolerance(hdr, tolerance);
1838 	msg_set_linkprio(hdr, priority);
1839 	msg_set_redundant_link(hdr, node_up);
1840 	msg_set_seq_gap(hdr, 0);
1841 	msg_set_seqno(hdr, l->snd_nxt + U16_MAX / 2);
1842 
1843 	if (mtyp == STATE_MSG) {
1844 		if (l->peer_caps & TIPC_LINK_PROTO_SEQNO)
1845 			msg_set_seqno(hdr, l->snd_nxt_state++);
1846 		msg_set_seq_gap(hdr, rcvgap);
1847 		bc_rcvgap = link_bc_rcv_gap(bcl);
1848 		msg_set_bc_gap(hdr, bc_rcvgap);
1849 		msg_set_probe(hdr, probe);
1850 		msg_set_is_keepalive(hdr, probe || probe_reply);
1851 		if (l->peer_caps & TIPC_GAP_ACK_BLOCK)
1852 			glen = tipc_build_gap_ack_blks(l, hdr);
1853 		tipc_mon_prep(l->net, data + glen, &dlen, mstate, l->bearer_id);
1854 		msg_set_size(hdr, INT_H_SIZE + glen + dlen);
1855 		skb_trim(skb, INT_H_SIZE + glen + dlen);
1856 		l->stats.sent_states++;
1857 		l->rcv_unacked = 0;
1858 	} else {
1859 		/* RESET_MSG or ACTIVATE_MSG */
1860 		if (mtyp == ACTIVATE_MSG) {
1861 			msg_set_dest_session_valid(hdr, 1);
1862 			msg_set_dest_session(hdr, l->peer_session);
1863 		}
1864 		msg_set_max_pkt(hdr, l->advertised_mtu);
1865 		strcpy(data, l->if_name);
1866 		msg_set_size(hdr, INT_H_SIZE + TIPC_MAX_IF_NAME);
1867 		skb_trim(skb, INT_H_SIZE + TIPC_MAX_IF_NAME);
1868 	}
1869 	if (probe)
1870 		l->stats.sent_probes++;
1871 	if (rcvgap)
1872 		l->stats.sent_nacks++;
1873 	if (bc_rcvgap)
1874 		bcl->stats.sent_nacks++;
1875 	skb->priority = TC_PRIO_CONTROL;
1876 	__skb_queue_tail(xmitq, skb);
1877 	trace_tipc_proto_build(skb, false, l->name);
1878 }
1879 
1880 void tipc_link_create_dummy_tnl_msg(struct tipc_link *l,
1881 				    struct sk_buff_head *xmitq)
1882 {
1883 	u32 onode = tipc_own_addr(l->net);
1884 	struct tipc_msg *hdr, *ihdr;
1885 	struct sk_buff_head tnlq;
1886 	struct sk_buff *skb;
1887 	u32 dnode = l->addr;
1888 
1889 	__skb_queue_head_init(&tnlq);
1890 	skb = tipc_msg_create(TUNNEL_PROTOCOL, FAILOVER_MSG,
1891 			      INT_H_SIZE, BASIC_H_SIZE,
1892 			      dnode, onode, 0, 0, 0);
1893 	if (!skb) {
1894 		pr_warn("%sunable to create tunnel packet\n", link_co_err);
1895 		return;
1896 	}
1897 
1898 	hdr = buf_msg(skb);
1899 	msg_set_msgcnt(hdr, 1);
1900 	msg_set_bearer_id(hdr, l->peer_bearer_id);
1901 
1902 	ihdr = (struct tipc_msg *)msg_data(hdr);
1903 	tipc_msg_init(onode, ihdr, TIPC_LOW_IMPORTANCE, TIPC_DIRECT_MSG,
1904 		      BASIC_H_SIZE, dnode);
1905 	msg_set_errcode(ihdr, TIPC_ERR_NO_PORT);
1906 	__skb_queue_tail(&tnlq, skb);
1907 	tipc_link_xmit(l, &tnlq, xmitq);
1908 }
1909 
1910 /* tipc_link_tnl_prepare(): prepare and return a list of tunnel packets
1911  * with contents of the link's transmit and backlog queues.
1912  */
1913 void tipc_link_tnl_prepare(struct tipc_link *l, struct tipc_link *tnl,
1914 			   int mtyp, struct sk_buff_head *xmitq)
1915 {
1916 	struct sk_buff_head *fdefq = &tnl->failover_deferdq;
1917 	struct sk_buff *skb, *tnlskb;
1918 	struct tipc_msg *hdr, tnlhdr;
1919 	struct sk_buff_head *queue = &l->transmq;
1920 	struct sk_buff_head tmpxq, tnlq, frags;
1921 	u16 pktlen, pktcnt, seqno = l->snd_nxt;
1922 	bool pktcnt_need_update = false;
1923 	u16 syncpt;
1924 	int rc;
1925 
1926 	if (!tnl)
1927 		return;
1928 
1929 	__skb_queue_head_init(&tnlq);
1930 	/* Link Synching:
1931 	 * From now on, send only one single ("dummy") SYNCH message
1932 	 * to peer. The SYNCH message does not contain any data, just
1933 	 * a header conveying the synch point to the peer.
1934 	 */
1935 	if (mtyp == SYNCH_MSG && (tnl->peer_caps & TIPC_TUNNEL_ENHANCED)) {
1936 		tnlskb = tipc_msg_create(TUNNEL_PROTOCOL, SYNCH_MSG,
1937 					 INT_H_SIZE, 0, l->addr,
1938 					 tipc_own_addr(l->net),
1939 					 0, 0, 0);
1940 		if (!tnlskb) {
1941 			pr_warn("%sunable to create dummy SYNCH_MSG\n",
1942 				link_co_err);
1943 			return;
1944 		}
1945 
1946 		hdr = buf_msg(tnlskb);
1947 		syncpt = l->snd_nxt + skb_queue_len(&l->backlogq) - 1;
1948 		msg_set_syncpt(hdr, syncpt);
1949 		msg_set_bearer_id(hdr, l->peer_bearer_id);
1950 		__skb_queue_tail(&tnlq, tnlskb);
1951 		tipc_link_xmit(tnl, &tnlq, xmitq);
1952 		return;
1953 	}
1954 
1955 	__skb_queue_head_init(&tmpxq);
1956 	__skb_queue_head_init(&frags);
1957 	/* At least one packet required for safe algorithm => add dummy */
1958 	skb = tipc_msg_create(TIPC_LOW_IMPORTANCE, TIPC_DIRECT_MSG,
1959 			      BASIC_H_SIZE, 0, l->addr, tipc_own_addr(l->net),
1960 			      0, 0, TIPC_ERR_NO_PORT);
1961 	if (!skb) {
1962 		pr_warn("%sunable to create tunnel packet\n", link_co_err);
1963 		return;
1964 	}
1965 	__skb_queue_tail(&tnlq, skb);
1966 	tipc_link_xmit(l, &tnlq, &tmpxq);
1967 	__skb_queue_purge(&tmpxq);
1968 
1969 	/* Initialize reusable tunnel packet header */
1970 	tipc_msg_init(tipc_own_addr(l->net), &tnlhdr, TUNNEL_PROTOCOL,
1971 		      mtyp, INT_H_SIZE, l->addr);
1972 	if (mtyp == SYNCH_MSG)
1973 		pktcnt = l->snd_nxt - buf_seqno(skb_peek(&l->transmq));
1974 	else
1975 		pktcnt = skb_queue_len(&l->transmq);
1976 	pktcnt += skb_queue_len(&l->backlogq);
1977 	msg_set_msgcnt(&tnlhdr, pktcnt);
1978 	msg_set_bearer_id(&tnlhdr, l->peer_bearer_id);
1979 tnl:
1980 	/* Wrap each packet into a tunnel packet */
1981 	skb_queue_walk(queue, skb) {
1982 		hdr = buf_msg(skb);
1983 		if (queue == &l->backlogq)
1984 			msg_set_seqno(hdr, seqno++);
1985 		pktlen = msg_size(hdr);
1986 
1987 		/* Tunnel link MTU is not large enough? This could be
1988 		 * due to:
1989 		 * 1) Link MTU has just changed or set differently;
1990 		 * 2) Or FAILOVER on the top of a SYNCH message
1991 		 *
1992 		 * The 2nd case should not happen if peer supports
1993 		 * TIPC_TUNNEL_ENHANCED
1994 		 */
1995 		if (pktlen > tnl->mtu - INT_H_SIZE) {
1996 			if (mtyp == FAILOVER_MSG &&
1997 			    (tnl->peer_caps & TIPC_TUNNEL_ENHANCED)) {
1998 				rc = tipc_msg_fragment(skb, &tnlhdr, tnl->mtu,
1999 						       &frags);
2000 				if (rc) {
2001 					pr_warn("%sunable to frag msg: rc %d\n",
2002 						link_co_err, rc);
2003 					return;
2004 				}
2005 				pktcnt += skb_queue_len(&frags) - 1;
2006 				pktcnt_need_update = true;
2007 				skb_queue_splice_tail_init(&frags, &tnlq);
2008 				continue;
2009 			}
2010 			/* Unluckily, peer doesn't have TIPC_TUNNEL_ENHANCED
2011 			 * => Just warn it and return!
2012 			 */
2013 			pr_warn_ratelimited("%stoo large msg <%d, %d>: %d!\n",
2014 					    link_co_err, msg_user(hdr),
2015 					    msg_type(hdr), msg_size(hdr));
2016 			return;
2017 		}
2018 
2019 		msg_set_size(&tnlhdr, pktlen + INT_H_SIZE);
2020 		tnlskb = tipc_buf_acquire(pktlen + INT_H_SIZE, GFP_ATOMIC);
2021 		if (!tnlskb) {
2022 			pr_warn("%sunable to send packet\n", link_co_err);
2023 			return;
2024 		}
2025 		skb_copy_to_linear_data(tnlskb, &tnlhdr, INT_H_SIZE);
2026 		skb_copy_to_linear_data_offset(tnlskb, INT_H_SIZE, hdr, pktlen);
2027 		__skb_queue_tail(&tnlq, tnlskb);
2028 	}
2029 	if (queue != &l->backlogq) {
2030 		queue = &l->backlogq;
2031 		goto tnl;
2032 	}
2033 
2034 	if (pktcnt_need_update)
2035 		skb_queue_walk(&tnlq, skb) {
2036 			hdr = buf_msg(skb);
2037 			msg_set_msgcnt(hdr, pktcnt);
2038 		}
2039 
2040 	tipc_link_xmit(tnl, &tnlq, xmitq);
2041 
2042 	if (mtyp == FAILOVER_MSG) {
2043 		tnl->drop_point = l->rcv_nxt;
2044 		tnl->failover_reasm_skb = l->reasm_buf;
2045 		l->reasm_buf = NULL;
2046 
2047 		/* Failover the link's deferdq */
2048 		if (unlikely(!skb_queue_empty(fdefq))) {
2049 			pr_warn("Link failover deferdq not empty: %d!\n",
2050 				skb_queue_len(fdefq));
2051 			__skb_queue_purge(fdefq);
2052 		}
2053 		skb_queue_splice_init(&l->deferdq, fdefq);
2054 	}
2055 }
2056 
2057 /**
2058  * tipc_link_failover_prepare() - prepare tnl for link failover
2059  *
2060  * This is a special version of the precursor - tipc_link_tnl_prepare(),
2061  * see the tipc_node_link_failover() for details
2062  *
2063  * @l: failover link
2064  * @tnl: tunnel link
2065  * @xmitq: queue for messages to be xmited
2066  */
2067 void tipc_link_failover_prepare(struct tipc_link *l, struct tipc_link *tnl,
2068 				struct sk_buff_head *xmitq)
2069 {
2070 	struct sk_buff_head *fdefq = &tnl->failover_deferdq;
2071 
2072 	tipc_link_create_dummy_tnl_msg(tnl, xmitq);
2073 
2074 	/* This failover link endpoint was never established before,
2075 	 * so it has not received anything from peer.
2076 	 * Otherwise, it must be a normal failover situation or the
2077 	 * node has entered SELF_DOWN_PEER_LEAVING and both peer nodes
2078 	 * would have to start over from scratch instead.
2079 	 */
2080 	tnl->drop_point = 1;
2081 	tnl->failover_reasm_skb = NULL;
2082 
2083 	/* Initiate the link's failover deferdq */
2084 	if (unlikely(!skb_queue_empty(fdefq))) {
2085 		pr_warn("Link failover deferdq not empty: %d!\n",
2086 			skb_queue_len(fdefq));
2087 		__skb_queue_purge(fdefq);
2088 	}
2089 }
2090 
2091 /* tipc_link_validate_msg(): validate message against current link state
2092  * Returns true if message should be accepted, otherwise false
2093  */
2094 bool tipc_link_validate_msg(struct tipc_link *l, struct tipc_msg *hdr)
2095 {
2096 	u16 curr_session = l->peer_session;
2097 	u16 session = msg_session(hdr);
2098 	int mtyp = msg_type(hdr);
2099 
2100 	if (msg_user(hdr) != LINK_PROTOCOL)
2101 		return true;
2102 
2103 	switch (mtyp) {
2104 	case RESET_MSG:
2105 		if (!l->in_session)
2106 			return true;
2107 		/* Accept only RESET with new session number */
2108 		return more(session, curr_session);
2109 	case ACTIVATE_MSG:
2110 		if (!l->in_session)
2111 			return true;
2112 		/* Accept only ACTIVATE with new or current session number */
2113 		return !less(session, curr_session);
2114 	case STATE_MSG:
2115 		/* Accept only STATE with current session number */
2116 		if (!l->in_session)
2117 			return false;
2118 		if (session != curr_session)
2119 			return false;
2120 		/* Extra sanity check */
2121 		if (!link_is_up(l) && msg_ack(hdr))
2122 			return false;
2123 		if (!(l->peer_caps & TIPC_LINK_PROTO_SEQNO))
2124 			return true;
2125 		/* Accept only STATE with new sequence number */
2126 		return !less(msg_seqno(hdr), l->rcv_nxt_state);
2127 	default:
2128 		return false;
2129 	}
2130 }
2131 
2132 /* tipc_link_proto_rcv(): receive link level protocol message :
2133  * Note that network plane id propagates through the network, and may
2134  * change at any time. The node with lowest numerical id determines
2135  * network plane
2136  */
2137 static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
2138 			       struct sk_buff_head *xmitq)
2139 {
2140 	struct tipc_msg *hdr = buf_msg(skb);
2141 	struct tipc_gap_ack_blks *ga = NULL;
2142 	bool reply = msg_probe(hdr), retransmitted = false;
2143 	u16 dlen = msg_data_sz(hdr), glen = 0;
2144 	u16 peers_snd_nxt =  msg_next_sent(hdr);
2145 	u16 peers_tol = msg_link_tolerance(hdr);
2146 	u16 peers_prio = msg_linkprio(hdr);
2147 	u16 gap = msg_seq_gap(hdr);
2148 	u16 ack = msg_ack(hdr);
2149 	u16 rcv_nxt = l->rcv_nxt;
2150 	u16 rcvgap = 0;
2151 	int mtyp = msg_type(hdr);
2152 	int rc = 0, released;
2153 	char *if_name;
2154 	void *data;
2155 
2156 	trace_tipc_proto_rcv(skb, false, l->name);
2157 	if (tipc_link_is_blocked(l) || !xmitq)
2158 		goto exit;
2159 
2160 	if (tipc_own_addr(l->net) > msg_prevnode(hdr))
2161 		l->net_plane = msg_net_plane(hdr);
2162 
2163 	skb_linearize(skb);
2164 	hdr = buf_msg(skb);
2165 	data = msg_data(hdr);
2166 
2167 	if (!tipc_link_validate_msg(l, hdr)) {
2168 		trace_tipc_skb_dump(skb, false, "PROTO invalid (1)!");
2169 		trace_tipc_link_dump(l, TIPC_DUMP_NONE, "PROTO invalid (1)!");
2170 		goto exit;
2171 	}
2172 
2173 	switch (mtyp) {
2174 	case RESET_MSG:
2175 	case ACTIVATE_MSG:
2176 		/* Complete own link name with peer's interface name */
2177 		if_name =  strrchr(l->name, ':') + 1;
2178 		if (sizeof(l->name) - (if_name - l->name) <= TIPC_MAX_IF_NAME)
2179 			break;
2180 		if (msg_data_sz(hdr) < TIPC_MAX_IF_NAME)
2181 			break;
2182 		strncpy(if_name, data, TIPC_MAX_IF_NAME);
2183 
2184 		/* Update own tolerance if peer indicates a non-zero value */
2185 		if (in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL)) {
2186 			l->tolerance = peers_tol;
2187 			l->bc_rcvlink->tolerance = peers_tol;
2188 		}
2189 		/* Update own priority if peer's priority is higher */
2190 		if (in_range(peers_prio, l->priority + 1, TIPC_MAX_LINK_PRI))
2191 			l->priority = peers_prio;
2192 
2193 		/* If peer is going down we want full re-establish cycle */
2194 		if (msg_peer_stopping(hdr)) {
2195 			rc = tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
2196 			break;
2197 		}
2198 
2199 		/* If this endpoint was re-created while peer was ESTABLISHING
2200 		 * it doesn't know current session number. Force re-synch.
2201 		 */
2202 		if (mtyp == ACTIVATE_MSG && msg_dest_session_valid(hdr) &&
2203 		    l->session != msg_dest_session(hdr)) {
2204 			if (less(l->session, msg_dest_session(hdr)))
2205 				l->session = msg_dest_session(hdr) + 1;
2206 			break;
2207 		}
2208 
2209 		/* ACTIVATE_MSG serves as PEER_RESET if link is already down */
2210 		if (mtyp == RESET_MSG || !link_is_up(l))
2211 			rc = tipc_link_fsm_evt(l, LINK_PEER_RESET_EVT);
2212 
2213 		/* ACTIVATE_MSG takes up link if it was already locally reset */
2214 		if (mtyp == ACTIVATE_MSG && l->state == LINK_ESTABLISHING)
2215 			rc = TIPC_LINK_UP_EVT;
2216 
2217 		l->peer_session = msg_session(hdr);
2218 		l->in_session = true;
2219 		l->peer_bearer_id = msg_bearer_id(hdr);
2220 		if (l->mtu > msg_max_pkt(hdr))
2221 			l->mtu = msg_max_pkt(hdr);
2222 		break;
2223 
2224 	case STATE_MSG:
2225 		l->rcv_nxt_state = msg_seqno(hdr) + 1;
2226 
2227 		/* Update own tolerance if peer indicates a non-zero value */
2228 		if (in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL)) {
2229 			l->tolerance = peers_tol;
2230 			l->bc_rcvlink->tolerance = peers_tol;
2231 		}
2232 		/* Update own prio if peer indicates a different value */
2233 		if ((peers_prio != l->priority) &&
2234 		    in_range(peers_prio, 1, TIPC_MAX_LINK_PRI)) {
2235 			l->priority = peers_prio;
2236 			rc = tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
2237 		}
2238 
2239 		l->silent_intv_cnt = 0;
2240 		l->stats.recv_states++;
2241 		if (msg_probe(hdr))
2242 			l->stats.recv_probes++;
2243 
2244 		if (!link_is_up(l)) {
2245 			if (l->state == LINK_ESTABLISHING)
2246 				rc = TIPC_LINK_UP_EVT;
2247 			break;
2248 		}
2249 
2250 		/* Receive Gap ACK blocks from peer if any */
2251 		glen = tipc_get_gap_ack_blks(&ga, l, hdr, true);
2252 
2253 		tipc_mon_rcv(l->net, data + glen, dlen - glen, l->addr,
2254 			     &l->mon_state, l->bearer_id);
2255 
2256 		/* Send NACK if peer has sent pkts we haven't received yet */
2257 		if ((reply || msg_is_keepalive(hdr)) &&
2258 		    more(peers_snd_nxt, rcv_nxt) &&
2259 		    !tipc_link_is_synching(l) &&
2260 		    skb_queue_empty(&l->deferdq))
2261 			rcvgap = peers_snd_nxt - l->rcv_nxt;
2262 		if (rcvgap || reply)
2263 			tipc_link_build_proto_msg(l, STATE_MSG, 0, reply,
2264 						  rcvgap, 0, 0, xmitq);
2265 
2266 		released = tipc_link_advance_transmq(l, l, ack, gap, ga, xmitq,
2267 						     &retransmitted, &rc);
2268 		if (gap)
2269 			l->stats.recv_nacks++;
2270 		if (released || retransmitted)
2271 			tipc_link_update_cwin(l, released, retransmitted);
2272 		if (released)
2273 			tipc_link_advance_backlog(l, xmitq);
2274 		if (unlikely(!skb_queue_empty(&l->wakeupq)))
2275 			link_prepare_wakeup(l);
2276 	}
2277 exit:
2278 	kfree_skb(skb);
2279 	return rc;
2280 }
2281 
2282 /* tipc_link_build_bc_proto_msg() - create broadcast protocol message
2283  */
2284 static bool tipc_link_build_bc_proto_msg(struct tipc_link *l, bool bcast,
2285 					 u16 peers_snd_nxt,
2286 					 struct sk_buff_head *xmitq)
2287 {
2288 	struct sk_buff *skb;
2289 	struct tipc_msg *hdr;
2290 	struct sk_buff *dfrd_skb = skb_peek(&l->deferdq);
2291 	u16 ack = l->rcv_nxt - 1;
2292 	u16 gap_to = peers_snd_nxt - 1;
2293 
2294 	skb = tipc_msg_create(BCAST_PROTOCOL, STATE_MSG, INT_H_SIZE,
2295 			      0, l->addr, tipc_own_addr(l->net), 0, 0, 0);
2296 	if (!skb)
2297 		return false;
2298 	hdr = buf_msg(skb);
2299 	msg_set_last_bcast(hdr, l->bc_sndlink->snd_nxt - 1);
2300 	msg_set_bcast_ack(hdr, ack);
2301 	msg_set_bcgap_after(hdr, ack);
2302 	if (dfrd_skb)
2303 		gap_to = buf_seqno(dfrd_skb) - 1;
2304 	msg_set_bcgap_to(hdr, gap_to);
2305 	msg_set_non_seq(hdr, bcast);
2306 	__skb_queue_tail(xmitq, skb);
2307 	return true;
2308 }
2309 
2310 /* tipc_link_build_bc_init_msg() - synchronize broadcast link endpoints.
2311  *
2312  * Give a newly added peer node the sequence number where it should
2313  * start receiving and acking broadcast packets.
2314  */
2315 static void tipc_link_build_bc_init_msg(struct tipc_link *l,
2316 					struct sk_buff_head *xmitq)
2317 {
2318 	struct sk_buff_head list;
2319 
2320 	__skb_queue_head_init(&list);
2321 	if (!tipc_link_build_bc_proto_msg(l->bc_rcvlink, false, 0, &list))
2322 		return;
2323 	msg_set_bc_ack_invalid(buf_msg(skb_peek(&list)), true);
2324 	tipc_link_xmit(l, &list, xmitq);
2325 }
2326 
2327 /* tipc_link_bc_init_rcv - receive initial broadcast synch data from peer
2328  */
2329 void tipc_link_bc_init_rcv(struct tipc_link *l, struct tipc_msg *hdr)
2330 {
2331 	int mtyp = msg_type(hdr);
2332 	u16 peers_snd_nxt = msg_bc_snd_nxt(hdr);
2333 
2334 	if (link_is_up(l))
2335 		return;
2336 
2337 	if (msg_user(hdr) == BCAST_PROTOCOL) {
2338 		l->rcv_nxt = peers_snd_nxt;
2339 		l->state = LINK_ESTABLISHED;
2340 		return;
2341 	}
2342 
2343 	if (l->peer_caps & TIPC_BCAST_SYNCH)
2344 		return;
2345 
2346 	if (msg_peer_node_is_up(hdr))
2347 		return;
2348 
2349 	/* Compatibility: accept older, less safe initial synch data */
2350 	if ((mtyp == RESET_MSG) || (mtyp == ACTIVATE_MSG))
2351 		l->rcv_nxt = peers_snd_nxt;
2352 }
2353 
2354 /* tipc_link_bc_sync_rcv - update rcv link according to peer's send state
2355  */
2356 int tipc_link_bc_sync_rcv(struct tipc_link *l, struct tipc_msg *hdr,
2357 			  struct sk_buff_head *xmitq)
2358 {
2359 	u16 peers_snd_nxt = msg_bc_snd_nxt(hdr);
2360 	int rc = 0;
2361 
2362 	if (!link_is_up(l))
2363 		return rc;
2364 
2365 	if (!msg_peer_node_is_up(hdr))
2366 		return rc;
2367 
2368 	/* Open when peer ackowledges our bcast init msg (pkt #1) */
2369 	if (msg_ack(hdr))
2370 		l->bc_peer_is_up = true;
2371 
2372 	if (!l->bc_peer_is_up)
2373 		return rc;
2374 
2375 	/* Ignore if peers_snd_nxt goes beyond receive window */
2376 	if (more(peers_snd_nxt, l->rcv_nxt + l->window))
2377 		return rc;
2378 
2379 	l->snd_nxt = peers_snd_nxt;
2380 	if (link_bc_rcv_gap(l))
2381 		rc |= TIPC_LINK_SND_STATE;
2382 
2383 	/* Return now if sender supports nack via STATE messages */
2384 	if (l->peer_caps & TIPC_BCAST_STATE_NACK)
2385 		return rc;
2386 
2387 	/* Otherwise, be backwards compatible */
2388 
2389 	if (!more(peers_snd_nxt, l->rcv_nxt)) {
2390 		l->nack_state = BC_NACK_SND_CONDITIONAL;
2391 		return 0;
2392 	}
2393 
2394 	/* Don't NACK if one was recently sent or peeked */
2395 	if (l->nack_state == BC_NACK_SND_SUPPRESS) {
2396 		l->nack_state = BC_NACK_SND_UNCONDITIONAL;
2397 		return 0;
2398 	}
2399 
2400 	/* Conditionally delay NACK sending until next synch rcv */
2401 	if (l->nack_state == BC_NACK_SND_CONDITIONAL) {
2402 		l->nack_state = BC_NACK_SND_UNCONDITIONAL;
2403 		if ((peers_snd_nxt - l->rcv_nxt) < TIPC_MIN_LINK_WIN)
2404 			return 0;
2405 	}
2406 
2407 	/* Send NACK now but suppress next one */
2408 	tipc_link_build_bc_proto_msg(l, true, peers_snd_nxt, xmitq);
2409 	l->nack_state = BC_NACK_SND_SUPPRESS;
2410 	return 0;
2411 }
2412 
2413 int tipc_link_bc_ack_rcv(struct tipc_link *r, u16 acked, u16 gap,
2414 			 struct tipc_gap_ack_blks *ga,
2415 			 struct sk_buff_head *xmitq,
2416 			 struct sk_buff_head *retrq)
2417 {
2418 	struct tipc_link *l = r->bc_sndlink;
2419 	bool unused = false;
2420 	int rc = 0;
2421 
2422 	if (!link_is_up(r) || !r->bc_peer_is_up)
2423 		return 0;
2424 
2425 	if (gap) {
2426 		l->stats.recv_nacks++;
2427 		r->stats.recv_nacks++;
2428 	}
2429 
2430 	if (less(acked, r->acked) || (acked == r->acked && !gap && !ga))
2431 		return 0;
2432 
2433 	trace_tipc_link_bc_ack(r, acked, gap, &l->transmq);
2434 	tipc_link_advance_transmq(l, r, acked, gap, ga, retrq, &unused, &rc);
2435 
2436 	tipc_link_advance_backlog(l, xmitq);
2437 	if (unlikely(!skb_queue_empty(&l->wakeupq)))
2438 		link_prepare_wakeup(l);
2439 
2440 	return rc;
2441 }
2442 
2443 /* tipc_link_bc_nack_rcv(): receive broadcast nack message
2444  * This function is here for backwards compatibility, since
2445  * no BCAST_PROTOCOL/STATE messages occur from TIPC v2.5.
2446  */
2447 int tipc_link_bc_nack_rcv(struct tipc_link *l, struct sk_buff *skb,
2448 			  struct sk_buff_head *xmitq)
2449 {
2450 	struct tipc_msg *hdr = buf_msg(skb);
2451 	u32 dnode = msg_destnode(hdr);
2452 	int mtyp = msg_type(hdr);
2453 	u16 acked = msg_bcast_ack(hdr);
2454 	u16 from = acked + 1;
2455 	u16 to = msg_bcgap_to(hdr);
2456 	u16 peers_snd_nxt = to + 1;
2457 	int rc = 0;
2458 
2459 	kfree_skb(skb);
2460 
2461 	if (!tipc_link_is_up(l) || !l->bc_peer_is_up)
2462 		return 0;
2463 
2464 	if (mtyp != STATE_MSG)
2465 		return 0;
2466 
2467 	if (dnode == tipc_own_addr(l->net)) {
2468 		rc = tipc_link_bc_ack_rcv(l, acked, to - acked, NULL, xmitq,
2469 					  xmitq);
2470 		l->stats.recv_nacks++;
2471 		return rc;
2472 	}
2473 
2474 	/* Msg for other node => suppress own NACK at next sync if applicable */
2475 	if (more(peers_snd_nxt, l->rcv_nxt) && !less(l->rcv_nxt, from))
2476 		l->nack_state = BC_NACK_SND_SUPPRESS;
2477 
2478 	return 0;
2479 }
2480 
2481 void tipc_link_set_queue_limits(struct tipc_link *l, u32 min_win, u32 max_win)
2482 {
2483 	int max_bulk = TIPC_MAX_PUBL / (l->mtu / ITEM_SIZE);
2484 
2485 	l->min_win = min_win;
2486 	l->ssthresh = max_win;
2487 	l->max_win = max_win;
2488 	l->window = min_win;
2489 	l->backlog[TIPC_LOW_IMPORTANCE].limit      = min_win * 2;
2490 	l->backlog[TIPC_MEDIUM_IMPORTANCE].limit   = min_win * 4;
2491 	l->backlog[TIPC_HIGH_IMPORTANCE].limit     = min_win * 6;
2492 	l->backlog[TIPC_CRITICAL_IMPORTANCE].limit = min_win * 8;
2493 	l->backlog[TIPC_SYSTEM_IMPORTANCE].limit   = max_bulk;
2494 }
2495 
2496 /**
2497  * link_reset_stats - reset link statistics
2498  * @l: pointer to link
2499  */
2500 void tipc_link_reset_stats(struct tipc_link *l)
2501 {
2502 	memset(&l->stats, 0, sizeof(l->stats));
2503 }
2504 
2505 static void link_print(struct tipc_link *l, const char *str)
2506 {
2507 	struct sk_buff *hskb = skb_peek(&l->transmq);
2508 	u16 head = hskb ? msg_seqno(buf_msg(hskb)) : l->snd_nxt - 1;
2509 	u16 tail = l->snd_nxt - 1;
2510 
2511 	pr_info("%s Link <%s> state %x\n", str, l->name, l->state);
2512 	pr_info("XMTQ: %u [%u-%u], BKLGQ: %u, SNDNX: %u, RCVNX: %u\n",
2513 		skb_queue_len(&l->transmq), head, tail,
2514 		skb_queue_len(&l->backlogq), l->snd_nxt, l->rcv_nxt);
2515 }
2516 
2517 /* Parse and validate nested (link) properties valid for media, bearer and link
2518  */
2519 int tipc_nl_parse_link_prop(struct nlattr *prop, struct nlattr *props[])
2520 {
2521 	int err;
2522 
2523 	err = nla_parse_nested_deprecated(props, TIPC_NLA_PROP_MAX, prop,
2524 					  tipc_nl_prop_policy, NULL);
2525 	if (err)
2526 		return err;
2527 
2528 	if (props[TIPC_NLA_PROP_PRIO]) {
2529 		u32 prio;
2530 
2531 		prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
2532 		if (prio > TIPC_MAX_LINK_PRI)
2533 			return -EINVAL;
2534 	}
2535 
2536 	if (props[TIPC_NLA_PROP_TOL]) {
2537 		u32 tol;
2538 
2539 		tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
2540 		if ((tol < TIPC_MIN_LINK_TOL) || (tol > TIPC_MAX_LINK_TOL))
2541 			return -EINVAL;
2542 	}
2543 
2544 	if (props[TIPC_NLA_PROP_WIN]) {
2545 		u32 max_win;
2546 
2547 		max_win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
2548 		if (max_win < TIPC_DEF_LINK_WIN || max_win > TIPC_MAX_LINK_WIN)
2549 			return -EINVAL;
2550 	}
2551 
2552 	return 0;
2553 }
2554 
2555 static int __tipc_nl_add_stats(struct sk_buff *skb, struct tipc_stats *s)
2556 {
2557 	int i;
2558 	struct nlattr *stats;
2559 
2560 	struct nla_map {
2561 		u32 key;
2562 		u32 val;
2563 	};
2564 
2565 	struct nla_map map[] = {
2566 		{TIPC_NLA_STATS_RX_INFO, 0},
2567 		{TIPC_NLA_STATS_RX_FRAGMENTS, s->recv_fragments},
2568 		{TIPC_NLA_STATS_RX_FRAGMENTED, s->recv_fragmented},
2569 		{TIPC_NLA_STATS_RX_BUNDLES, s->recv_bundles},
2570 		{TIPC_NLA_STATS_RX_BUNDLED, s->recv_bundled},
2571 		{TIPC_NLA_STATS_TX_INFO, 0},
2572 		{TIPC_NLA_STATS_TX_FRAGMENTS, s->sent_fragments},
2573 		{TIPC_NLA_STATS_TX_FRAGMENTED, s->sent_fragmented},
2574 		{TIPC_NLA_STATS_TX_BUNDLES, s->sent_bundles},
2575 		{TIPC_NLA_STATS_TX_BUNDLED, s->sent_bundled},
2576 		{TIPC_NLA_STATS_MSG_PROF_TOT, (s->msg_length_counts) ?
2577 			s->msg_length_counts : 1},
2578 		{TIPC_NLA_STATS_MSG_LEN_CNT, s->msg_length_counts},
2579 		{TIPC_NLA_STATS_MSG_LEN_TOT, s->msg_lengths_total},
2580 		{TIPC_NLA_STATS_MSG_LEN_P0, s->msg_length_profile[0]},
2581 		{TIPC_NLA_STATS_MSG_LEN_P1, s->msg_length_profile[1]},
2582 		{TIPC_NLA_STATS_MSG_LEN_P2, s->msg_length_profile[2]},
2583 		{TIPC_NLA_STATS_MSG_LEN_P3, s->msg_length_profile[3]},
2584 		{TIPC_NLA_STATS_MSG_LEN_P4, s->msg_length_profile[4]},
2585 		{TIPC_NLA_STATS_MSG_LEN_P5, s->msg_length_profile[5]},
2586 		{TIPC_NLA_STATS_MSG_LEN_P6, s->msg_length_profile[6]},
2587 		{TIPC_NLA_STATS_RX_STATES, s->recv_states},
2588 		{TIPC_NLA_STATS_RX_PROBES, s->recv_probes},
2589 		{TIPC_NLA_STATS_RX_NACKS, s->recv_nacks},
2590 		{TIPC_NLA_STATS_RX_DEFERRED, s->deferred_recv},
2591 		{TIPC_NLA_STATS_TX_STATES, s->sent_states},
2592 		{TIPC_NLA_STATS_TX_PROBES, s->sent_probes},
2593 		{TIPC_NLA_STATS_TX_NACKS, s->sent_nacks},
2594 		{TIPC_NLA_STATS_TX_ACKS, s->sent_acks},
2595 		{TIPC_NLA_STATS_RETRANSMITTED, s->retransmitted},
2596 		{TIPC_NLA_STATS_DUPLICATES, s->duplicates},
2597 		{TIPC_NLA_STATS_LINK_CONGS, s->link_congs},
2598 		{TIPC_NLA_STATS_MAX_QUEUE, s->max_queue_sz},
2599 		{TIPC_NLA_STATS_AVG_QUEUE, s->queue_sz_counts ?
2600 			(s->accu_queue_sz / s->queue_sz_counts) : 0}
2601 	};
2602 
2603 	stats = nla_nest_start_noflag(skb, TIPC_NLA_LINK_STATS);
2604 	if (!stats)
2605 		return -EMSGSIZE;
2606 
2607 	for (i = 0; i <  ARRAY_SIZE(map); i++)
2608 		if (nla_put_u32(skb, map[i].key, map[i].val))
2609 			goto msg_full;
2610 
2611 	nla_nest_end(skb, stats);
2612 
2613 	return 0;
2614 msg_full:
2615 	nla_nest_cancel(skb, stats);
2616 
2617 	return -EMSGSIZE;
2618 }
2619 
2620 /* Caller should hold appropriate locks to protect the link */
2621 int __tipc_nl_add_link(struct net *net, struct tipc_nl_msg *msg,
2622 		       struct tipc_link *link, int nlflags)
2623 {
2624 	u32 self = tipc_own_addr(net);
2625 	struct nlattr *attrs;
2626 	struct nlattr *prop;
2627 	void *hdr;
2628 	int err;
2629 
2630 	hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
2631 			  nlflags, TIPC_NL_LINK_GET);
2632 	if (!hdr)
2633 		return -EMSGSIZE;
2634 
2635 	attrs = nla_nest_start_noflag(msg->skb, TIPC_NLA_LINK);
2636 	if (!attrs)
2637 		goto msg_full;
2638 
2639 	if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, link->name))
2640 		goto attr_msg_full;
2641 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_DEST, tipc_cluster_mask(self)))
2642 		goto attr_msg_full;
2643 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_MTU, link->mtu))
2644 		goto attr_msg_full;
2645 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, link->stats.recv_pkts))
2646 		goto attr_msg_full;
2647 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, link->stats.sent_pkts))
2648 		goto attr_msg_full;
2649 
2650 	if (tipc_link_is_up(link))
2651 		if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
2652 			goto attr_msg_full;
2653 	if (link->active)
2654 		if (nla_put_flag(msg->skb, TIPC_NLA_LINK_ACTIVE))
2655 			goto attr_msg_full;
2656 
2657 	prop = nla_nest_start_noflag(msg->skb, TIPC_NLA_LINK_PROP);
2658 	if (!prop)
2659 		goto attr_msg_full;
2660 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
2661 		goto prop_msg_full;
2662 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_TOL, link->tolerance))
2663 		goto prop_msg_full;
2664 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN,
2665 			link->window))
2666 		goto prop_msg_full;
2667 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
2668 		goto prop_msg_full;
2669 	nla_nest_end(msg->skb, prop);
2670 
2671 	err = __tipc_nl_add_stats(msg->skb, &link->stats);
2672 	if (err)
2673 		goto attr_msg_full;
2674 
2675 	nla_nest_end(msg->skb, attrs);
2676 	genlmsg_end(msg->skb, hdr);
2677 
2678 	return 0;
2679 
2680 prop_msg_full:
2681 	nla_nest_cancel(msg->skb, prop);
2682 attr_msg_full:
2683 	nla_nest_cancel(msg->skb, attrs);
2684 msg_full:
2685 	genlmsg_cancel(msg->skb, hdr);
2686 
2687 	return -EMSGSIZE;
2688 }
2689 
2690 static int __tipc_nl_add_bc_link_stat(struct sk_buff *skb,
2691 				      struct tipc_stats *stats)
2692 {
2693 	int i;
2694 	struct nlattr *nest;
2695 
2696 	struct nla_map {
2697 		__u32 key;
2698 		__u32 val;
2699 	};
2700 
2701 	struct nla_map map[] = {
2702 		{TIPC_NLA_STATS_RX_INFO, stats->recv_pkts},
2703 		{TIPC_NLA_STATS_RX_FRAGMENTS, stats->recv_fragments},
2704 		{TIPC_NLA_STATS_RX_FRAGMENTED, stats->recv_fragmented},
2705 		{TIPC_NLA_STATS_RX_BUNDLES, stats->recv_bundles},
2706 		{TIPC_NLA_STATS_RX_BUNDLED, stats->recv_bundled},
2707 		{TIPC_NLA_STATS_TX_INFO, stats->sent_pkts},
2708 		{TIPC_NLA_STATS_TX_FRAGMENTS, stats->sent_fragments},
2709 		{TIPC_NLA_STATS_TX_FRAGMENTED, stats->sent_fragmented},
2710 		{TIPC_NLA_STATS_TX_BUNDLES, stats->sent_bundles},
2711 		{TIPC_NLA_STATS_TX_BUNDLED, stats->sent_bundled},
2712 		{TIPC_NLA_STATS_RX_NACKS, stats->recv_nacks},
2713 		{TIPC_NLA_STATS_RX_DEFERRED, stats->deferred_recv},
2714 		{TIPC_NLA_STATS_TX_NACKS, stats->sent_nacks},
2715 		{TIPC_NLA_STATS_TX_ACKS, stats->sent_acks},
2716 		{TIPC_NLA_STATS_RETRANSMITTED, stats->retransmitted},
2717 		{TIPC_NLA_STATS_DUPLICATES, stats->duplicates},
2718 		{TIPC_NLA_STATS_LINK_CONGS, stats->link_congs},
2719 		{TIPC_NLA_STATS_MAX_QUEUE, stats->max_queue_sz},
2720 		{TIPC_NLA_STATS_AVG_QUEUE, stats->queue_sz_counts ?
2721 			(stats->accu_queue_sz / stats->queue_sz_counts) : 0}
2722 	};
2723 
2724 	nest = nla_nest_start_noflag(skb, TIPC_NLA_LINK_STATS);
2725 	if (!nest)
2726 		return -EMSGSIZE;
2727 
2728 	for (i = 0; i <  ARRAY_SIZE(map); i++)
2729 		if (nla_put_u32(skb, map[i].key, map[i].val))
2730 			goto msg_full;
2731 
2732 	nla_nest_end(skb, nest);
2733 
2734 	return 0;
2735 msg_full:
2736 	nla_nest_cancel(skb, nest);
2737 
2738 	return -EMSGSIZE;
2739 }
2740 
2741 int tipc_nl_add_bc_link(struct net *net, struct tipc_nl_msg *msg,
2742 			struct tipc_link *bcl)
2743 {
2744 	int err;
2745 	void *hdr;
2746 	struct nlattr *attrs;
2747 	struct nlattr *prop;
2748 	u32 bc_mode = tipc_bcast_get_broadcast_mode(net);
2749 	u32 bc_ratio = tipc_bcast_get_broadcast_ratio(net);
2750 
2751 	if (!bcl)
2752 		return 0;
2753 
2754 	tipc_bcast_lock(net);
2755 
2756 	hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
2757 			  NLM_F_MULTI, TIPC_NL_LINK_GET);
2758 	if (!hdr) {
2759 		tipc_bcast_unlock(net);
2760 		return -EMSGSIZE;
2761 	}
2762 
2763 	attrs = nla_nest_start_noflag(msg->skb, TIPC_NLA_LINK);
2764 	if (!attrs)
2765 		goto msg_full;
2766 
2767 	/* The broadcast link is always up */
2768 	if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
2769 		goto attr_msg_full;
2770 
2771 	if (nla_put_flag(msg->skb, TIPC_NLA_LINK_BROADCAST))
2772 		goto attr_msg_full;
2773 	if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, bcl->name))
2774 		goto attr_msg_full;
2775 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, 0))
2776 		goto attr_msg_full;
2777 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, 0))
2778 		goto attr_msg_full;
2779 
2780 	prop = nla_nest_start_noflag(msg->skb, TIPC_NLA_LINK_PROP);
2781 	if (!prop)
2782 		goto attr_msg_full;
2783 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN, bcl->max_win))
2784 		goto prop_msg_full;
2785 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_BROADCAST, bc_mode))
2786 		goto prop_msg_full;
2787 	if (bc_mode & BCLINK_MODE_SEL)
2788 		if (nla_put_u32(msg->skb, TIPC_NLA_PROP_BROADCAST_RATIO,
2789 				bc_ratio))
2790 			goto prop_msg_full;
2791 	nla_nest_end(msg->skb, prop);
2792 
2793 	err = __tipc_nl_add_bc_link_stat(msg->skb, &bcl->stats);
2794 	if (err)
2795 		goto attr_msg_full;
2796 
2797 	tipc_bcast_unlock(net);
2798 	nla_nest_end(msg->skb, attrs);
2799 	genlmsg_end(msg->skb, hdr);
2800 
2801 	return 0;
2802 
2803 prop_msg_full:
2804 	nla_nest_cancel(msg->skb, prop);
2805 attr_msg_full:
2806 	nla_nest_cancel(msg->skb, attrs);
2807 msg_full:
2808 	tipc_bcast_unlock(net);
2809 	genlmsg_cancel(msg->skb, hdr);
2810 
2811 	return -EMSGSIZE;
2812 }
2813 
2814 void tipc_link_set_tolerance(struct tipc_link *l, u32 tol,
2815 			     struct sk_buff_head *xmitq)
2816 {
2817 	l->tolerance = tol;
2818 	if (l->bc_rcvlink)
2819 		l->bc_rcvlink->tolerance = tol;
2820 	if (link_is_up(l))
2821 		tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, tol, 0, xmitq);
2822 }
2823 
2824 void tipc_link_set_prio(struct tipc_link *l, u32 prio,
2825 			struct sk_buff_head *xmitq)
2826 {
2827 	l->priority = prio;
2828 	tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, 0, prio, xmitq);
2829 }
2830 
2831 void tipc_link_set_abort_limit(struct tipc_link *l, u32 limit)
2832 {
2833 	l->abort_limit = limit;
2834 }
2835 
2836 /**
2837  * tipc_link_dump - dump TIPC link data
2838  * @l: tipc link to be dumped
2839  * @dqueues: bitmask to decide if any link queue to be dumped?
2840  *           - TIPC_DUMP_NONE: don't dump link queues
2841  *           - TIPC_DUMP_TRANSMQ: dump link transmq queue
2842  *           - TIPC_DUMP_BACKLOGQ: dump link backlog queue
2843  *           - TIPC_DUMP_DEFERDQ: dump link deferd queue
2844  *           - TIPC_DUMP_INPUTQ: dump link input queue
2845  *           - TIPC_DUMP_WAKEUP: dump link wakeup queue
2846  *           - TIPC_DUMP_ALL: dump all the link queues above
2847  * @buf: returned buffer of dump data in format
2848  */
2849 int tipc_link_dump(struct tipc_link *l, u16 dqueues, char *buf)
2850 {
2851 	int i = 0;
2852 	size_t sz = (dqueues) ? LINK_LMAX : LINK_LMIN;
2853 	struct sk_buff_head *list;
2854 	struct sk_buff *hskb, *tskb;
2855 	u32 len;
2856 
2857 	if (!l) {
2858 		i += scnprintf(buf, sz, "link data: (null)\n");
2859 		return i;
2860 	}
2861 
2862 	i += scnprintf(buf, sz, "link data: %x", l->addr);
2863 	i += scnprintf(buf + i, sz - i, " %x", l->state);
2864 	i += scnprintf(buf + i, sz - i, " %u", l->in_session);
2865 	i += scnprintf(buf + i, sz - i, " %u", l->session);
2866 	i += scnprintf(buf + i, sz - i, " %u", l->peer_session);
2867 	i += scnprintf(buf + i, sz - i, " %u", l->snd_nxt);
2868 	i += scnprintf(buf + i, sz - i, " %u", l->rcv_nxt);
2869 	i += scnprintf(buf + i, sz - i, " %u", l->snd_nxt_state);
2870 	i += scnprintf(buf + i, sz - i, " %u", l->rcv_nxt_state);
2871 	i += scnprintf(buf + i, sz - i, " %x", l->peer_caps);
2872 	i += scnprintf(buf + i, sz - i, " %u", l->silent_intv_cnt);
2873 	i += scnprintf(buf + i, sz - i, " %u", l->rst_cnt);
2874 	i += scnprintf(buf + i, sz - i, " %u", 0);
2875 	i += scnprintf(buf + i, sz - i, " %u", 0);
2876 	i += scnprintf(buf + i, sz - i, " %u", l->acked);
2877 
2878 	list = &l->transmq;
2879 	len = skb_queue_len(list);
2880 	hskb = skb_peek(list);
2881 	tskb = skb_peek_tail(list);
2882 	i += scnprintf(buf + i, sz - i, " | %u %u %u", len,
2883 		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
2884 		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
2885 
2886 	list = &l->deferdq;
2887 	len = skb_queue_len(list);
2888 	hskb = skb_peek(list);
2889 	tskb = skb_peek_tail(list);
2890 	i += scnprintf(buf + i, sz - i, " | %u %u %u", len,
2891 		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
2892 		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
2893 
2894 	list = &l->backlogq;
2895 	len = skb_queue_len(list);
2896 	hskb = skb_peek(list);
2897 	tskb = skb_peek_tail(list);
2898 	i += scnprintf(buf + i, sz - i, " | %u %u %u", len,
2899 		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
2900 		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
2901 
2902 	list = l->inputq;
2903 	len = skb_queue_len(list);
2904 	hskb = skb_peek(list);
2905 	tskb = skb_peek_tail(list);
2906 	i += scnprintf(buf + i, sz - i, " | %u %u %u\n", len,
2907 		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
2908 		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
2909 
2910 	if (dqueues & TIPC_DUMP_TRANSMQ) {
2911 		i += scnprintf(buf + i, sz - i, "transmq: ");
2912 		i += tipc_list_dump(&l->transmq, false, buf + i);
2913 	}
2914 	if (dqueues & TIPC_DUMP_BACKLOGQ) {
2915 		i += scnprintf(buf + i, sz - i,
2916 			       "backlogq: <%u %u %u %u %u>, ",
2917 			       l->backlog[TIPC_LOW_IMPORTANCE].len,
2918 			       l->backlog[TIPC_MEDIUM_IMPORTANCE].len,
2919 			       l->backlog[TIPC_HIGH_IMPORTANCE].len,
2920 			       l->backlog[TIPC_CRITICAL_IMPORTANCE].len,
2921 			       l->backlog[TIPC_SYSTEM_IMPORTANCE].len);
2922 		i += tipc_list_dump(&l->backlogq, false, buf + i);
2923 	}
2924 	if (dqueues & TIPC_DUMP_DEFERDQ) {
2925 		i += scnprintf(buf + i, sz - i, "deferdq: ");
2926 		i += tipc_list_dump(&l->deferdq, false, buf + i);
2927 	}
2928 	if (dqueues & TIPC_DUMP_INPUTQ) {
2929 		i += scnprintf(buf + i, sz - i, "inputq: ");
2930 		i += tipc_list_dump(l->inputq, false, buf + i);
2931 	}
2932 	if (dqueues & TIPC_DUMP_WAKEUP) {
2933 		i += scnprintf(buf + i, sz - i, "wakeup: ");
2934 		i += tipc_list_dump(&l->wakeupq, false, buf + i);
2935 	}
2936 
2937 	return i;
2938 }
2939