xref: /openbmc/linux/net/tipc/link.c (revision 7e60e389)
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  * @session: session to be used by link
124  * @snd_nxt_state: next send seq number
125  * @rcv_nxt_state: next rcv seq number
126  * @in_session: have received ACTIVATE_MSG from peer
127  * @active: link is active
128  * @if_name: associated interface name
129  * @rst_cnt: link reset counter
130  * @drop_point: seq number for failover handling (FIXME)
131  * @failover_reasm_skb: saved failover msg ptr (FIXME)
132  * @failover_deferdq: deferred message queue for failover processing (FIXME)
133  * @transmq: the link's transmit queue
134  * @backlog: link's backlog by priority (importance)
135  * @snd_nxt: next sequence number to be used
136  * @rcv_unacked: # messages read by user, but not yet acked back to peer
137  * @deferdq: deferred receive queue
138  * @window: sliding window size for congestion handling
139  * @min_win: minimal send window to be used by link
140  * @ssthresh: slow start threshold for congestion handling
141  * @max_win: maximal send window to be used by link
142  * @cong_acks: congestion acks for congestion avoidance (FIXME)
143  * @checkpoint: seq number for congestion window size handling
144  * @reasm_tnlmsg: fragmentation/reassembly area for tunnel protocol message
145  * @last_gap: last gap ack blocks for bcast (FIXME)
146  * @last_ga: ptr to gap ack blocks
147  * @bc_rcvlink: the peer specific link used for broadcast reception
148  * @bc_sndlink: the namespace global link used for broadcast sending
149  * @nack_state: bcast nack state
150  * @bc_peer_is_up: peer has acked the bcast init msg
151  */
152 struct tipc_link {
153 	u32 addr;
154 	char name[TIPC_MAX_LINK_NAME];
155 	struct net *net;
156 
157 	/* Management and link supervision data */
158 	u16 peer_session;
159 	u16 session;
160 	u16 snd_nxt_state;
161 	u16 rcv_nxt_state;
162 	u32 peer_bearer_id;
163 	u32 bearer_id;
164 	u32 tolerance;
165 	u32 abort_limit;
166 	u32 state;
167 	u16 peer_caps;
168 	bool in_session;
169 	bool active;
170 	u32 silent_intv_cnt;
171 	char if_name[TIPC_MAX_IF_NAME];
172 	u32 priority;
173 	char net_plane;
174 	struct tipc_mon_state mon_state;
175 	u16 rst_cnt;
176 
177 	/* Failover/synch */
178 	u16 drop_point;
179 	struct sk_buff *failover_reasm_skb;
180 	struct sk_buff_head failover_deferdq;
181 
182 	/* Max packet negotiation */
183 	u16 mtu;
184 	u16 advertised_mtu;
185 
186 	/* Sending */
187 	struct sk_buff_head transmq;
188 	struct sk_buff_head backlogq;
189 	struct {
190 		u16 len;
191 		u16 limit;
192 		struct sk_buff *target_bskb;
193 	} backlog[5];
194 	u16 snd_nxt;
195 
196 	/* Reception */
197 	u16 rcv_nxt;
198 	u32 rcv_unacked;
199 	struct sk_buff_head deferdq;
200 	struct sk_buff_head *inputq;
201 	struct sk_buff_head *namedq;
202 
203 	/* Congestion handling */
204 	struct sk_buff_head wakeupq;
205 	u16 window;
206 	u16 min_win;
207 	u16 ssthresh;
208 	u16 max_win;
209 	u16 cong_acks;
210 	u16 checkpoint;
211 
212 	/* Fragmentation/reassembly */
213 	struct sk_buff *reasm_buf;
214 	struct sk_buff *reasm_tnlmsg;
215 
216 	/* Broadcast */
217 	u16 ackers;
218 	u16 acked;
219 	u16 last_gap;
220 	struct tipc_gap_ack_blks *last_ga;
221 	struct tipc_link *bc_rcvlink;
222 	struct tipc_link *bc_sndlink;
223 	u8 nack_state;
224 	bool bc_peer_is_up;
225 
226 	/* Statistics */
227 	struct tipc_stats stats;
228 };
229 
230 /*
231  * Error message prefixes
232  */
233 static const char *link_co_err = "Link tunneling error, ";
234 static const char *link_rst_msg = "Resetting link ";
235 
236 /* Send states for broadcast NACKs
237  */
238 enum {
239 	BC_NACK_SND_CONDITIONAL,
240 	BC_NACK_SND_UNCONDITIONAL,
241 	BC_NACK_SND_SUPPRESS,
242 };
243 
244 #define TIPC_BC_RETR_LIM  (jiffies + msecs_to_jiffies(10))
245 #define TIPC_UC_RETR_TIME (jiffies + msecs_to_jiffies(1))
246 
247 /* Link FSM states:
248  */
249 enum {
250 	LINK_ESTABLISHED     = 0xe,
251 	LINK_ESTABLISHING    = 0xe  << 4,
252 	LINK_RESET           = 0x1  << 8,
253 	LINK_RESETTING       = 0x2  << 12,
254 	LINK_PEER_RESET      = 0xd  << 16,
255 	LINK_FAILINGOVER     = 0xf  << 20,
256 	LINK_SYNCHING        = 0xc  << 24
257 };
258 
259 /* Link FSM state checking routines
260  */
261 static int link_is_up(struct tipc_link *l)
262 {
263 	return l->state & (LINK_ESTABLISHED | LINK_SYNCHING);
264 }
265 
266 static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
267 			       struct sk_buff_head *xmitq);
268 static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
269 				      bool probe_reply, u16 rcvgap,
270 				      int tolerance, int priority,
271 				      struct sk_buff_head *xmitq);
272 static void link_print(struct tipc_link *l, const char *str);
273 static int tipc_link_build_nack_msg(struct tipc_link *l,
274 				    struct sk_buff_head *xmitq);
275 static void tipc_link_build_bc_init_msg(struct tipc_link *l,
276 					struct sk_buff_head *xmitq);
277 static u8 __tipc_build_gap_ack_blks(struct tipc_gap_ack_blks *ga,
278 				    struct tipc_link *l, u8 start_index);
279 static u16 tipc_build_gap_ack_blks(struct tipc_link *l, struct tipc_msg *hdr);
280 static int tipc_link_advance_transmq(struct tipc_link *l, struct tipc_link *r,
281 				     u16 acked, u16 gap,
282 				     struct tipc_gap_ack_blks *ga,
283 				     struct sk_buff_head *xmitq,
284 				     bool *retransmitted, int *rc);
285 static void tipc_link_update_cwin(struct tipc_link *l, int released,
286 				  bool retransmitted);
287 /*
288  *  Simple non-static link routines (i.e. referenced outside this file)
289  */
290 bool tipc_link_is_up(struct tipc_link *l)
291 {
292 	return link_is_up(l);
293 }
294 
295 bool tipc_link_peer_is_down(struct tipc_link *l)
296 {
297 	return l->state == LINK_PEER_RESET;
298 }
299 
300 bool tipc_link_is_reset(struct tipc_link *l)
301 {
302 	return l->state & (LINK_RESET | LINK_FAILINGOVER | LINK_ESTABLISHING);
303 }
304 
305 bool tipc_link_is_establishing(struct tipc_link *l)
306 {
307 	return l->state == LINK_ESTABLISHING;
308 }
309 
310 bool tipc_link_is_synching(struct tipc_link *l)
311 {
312 	return l->state == LINK_SYNCHING;
313 }
314 
315 bool tipc_link_is_failingover(struct tipc_link *l)
316 {
317 	return l->state == LINK_FAILINGOVER;
318 }
319 
320 bool tipc_link_is_blocked(struct tipc_link *l)
321 {
322 	return l->state & (LINK_RESETTING | LINK_PEER_RESET | LINK_FAILINGOVER);
323 }
324 
325 static bool link_is_bc_sndlink(struct tipc_link *l)
326 {
327 	return !l->bc_sndlink;
328 }
329 
330 static bool link_is_bc_rcvlink(struct tipc_link *l)
331 {
332 	return ((l->bc_rcvlink == l) && !link_is_bc_sndlink(l));
333 }
334 
335 void tipc_link_set_active(struct tipc_link *l, bool active)
336 {
337 	l->active = active;
338 }
339 
340 u32 tipc_link_id(struct tipc_link *l)
341 {
342 	return l->peer_bearer_id << 16 | l->bearer_id;
343 }
344 
345 int tipc_link_min_win(struct tipc_link *l)
346 {
347 	return l->min_win;
348 }
349 
350 int tipc_link_max_win(struct tipc_link *l)
351 {
352 	return l->max_win;
353 }
354 
355 int tipc_link_prio(struct tipc_link *l)
356 {
357 	return l->priority;
358 }
359 
360 unsigned long tipc_link_tolerance(struct tipc_link *l)
361 {
362 	return l->tolerance;
363 }
364 
365 struct sk_buff_head *tipc_link_inputq(struct tipc_link *l)
366 {
367 	return l->inputq;
368 }
369 
370 char tipc_link_plane(struct tipc_link *l)
371 {
372 	return l->net_plane;
373 }
374 
375 void tipc_link_update_caps(struct tipc_link *l, u16 capabilities)
376 {
377 	l->peer_caps = capabilities;
378 }
379 
380 void tipc_link_add_bc_peer(struct tipc_link *snd_l,
381 			   struct tipc_link *uc_l,
382 			   struct sk_buff_head *xmitq)
383 {
384 	struct tipc_link *rcv_l = uc_l->bc_rcvlink;
385 
386 	snd_l->ackers++;
387 	rcv_l->acked = snd_l->snd_nxt - 1;
388 	snd_l->state = LINK_ESTABLISHED;
389 	tipc_link_build_bc_init_msg(uc_l, xmitq);
390 }
391 
392 void tipc_link_remove_bc_peer(struct tipc_link *snd_l,
393 			      struct tipc_link *rcv_l,
394 			      struct sk_buff_head *xmitq)
395 {
396 	u16 ack = snd_l->snd_nxt - 1;
397 
398 	snd_l->ackers--;
399 	rcv_l->bc_peer_is_up = true;
400 	rcv_l->state = LINK_ESTABLISHED;
401 	tipc_link_bc_ack_rcv(rcv_l, ack, 0, NULL, xmitq, NULL);
402 	trace_tipc_link_reset(rcv_l, TIPC_DUMP_ALL, "bclink removed!");
403 	tipc_link_reset(rcv_l);
404 	rcv_l->state = LINK_RESET;
405 	if (!snd_l->ackers) {
406 		trace_tipc_link_reset(snd_l, TIPC_DUMP_ALL, "zero ackers!");
407 		tipc_link_reset(snd_l);
408 		snd_l->state = LINK_RESET;
409 		__skb_queue_purge(xmitq);
410 	}
411 }
412 
413 int tipc_link_bc_peers(struct tipc_link *l)
414 {
415 	return l->ackers;
416 }
417 
418 static u16 link_bc_rcv_gap(struct tipc_link *l)
419 {
420 	struct sk_buff *skb = skb_peek(&l->deferdq);
421 	u16 gap = 0;
422 
423 	if (more(l->snd_nxt, l->rcv_nxt))
424 		gap = l->snd_nxt - l->rcv_nxt;
425 	if (skb)
426 		gap = buf_seqno(skb) - l->rcv_nxt;
427 	return gap;
428 }
429 
430 void tipc_link_set_mtu(struct tipc_link *l, int mtu)
431 {
432 	l->mtu = mtu;
433 }
434 
435 int tipc_link_mtu(struct tipc_link *l)
436 {
437 	return l->mtu;
438 }
439 
440 int tipc_link_mss(struct tipc_link *l)
441 {
442 #ifdef CONFIG_TIPC_CRYPTO
443 	return l->mtu - INT_H_SIZE - EMSG_OVERHEAD;
444 #else
445 	return l->mtu - INT_H_SIZE;
446 #endif
447 }
448 
449 u16 tipc_link_rcv_nxt(struct tipc_link *l)
450 {
451 	return l->rcv_nxt;
452 }
453 
454 u16 tipc_link_acked(struct tipc_link *l)
455 {
456 	return l->acked;
457 }
458 
459 char *tipc_link_name(struct tipc_link *l)
460 {
461 	return l->name;
462 }
463 
464 u32 tipc_link_state(struct tipc_link *l)
465 {
466 	return l->state;
467 }
468 
469 /**
470  * tipc_link_create - create a new link
471  * @net: pointer to associated network namespace
472  * @if_name: associated interface name
473  * @bearer_id: id (index) of associated bearer
474  * @tolerance: link tolerance to be used by link
475  * @net_plane: network plane (A,B,c..) this link belongs to
476  * @mtu: mtu to be advertised by link
477  * @priority: priority to be used by link
478  * @min_win: minimal send window to be used by link
479  * @max_win: maximal send window to be used by link
480  * @session: session to be used by link
481  * @peer: node id of peer node
482  * @peer_caps: bitmap describing peer node capabilities
483  * @bc_sndlink: the namespace global link used for broadcast sending
484  * @bc_rcvlink: the peer specific link used for broadcast reception
485  * @inputq: queue to put messages ready for delivery
486  * @namedq: queue to put binding table update messages ready for delivery
487  * @link: return value, pointer to put the created link
488  * @self: local unicast link id
489  * @peer_id: 128-bit ID of peer
490  *
491  * Return: true if link was created, otherwise false
492  */
493 bool tipc_link_create(struct net *net, char *if_name, int bearer_id,
494 		      int tolerance, char net_plane, u32 mtu, int priority,
495 		      u32 min_win, u32 max_win, u32 session, u32 self,
496 		      u32 peer, u8 *peer_id, u16 peer_caps,
497 		      struct tipc_link *bc_sndlink,
498 		      struct tipc_link *bc_rcvlink,
499 		      struct sk_buff_head *inputq,
500 		      struct sk_buff_head *namedq,
501 		      struct tipc_link **link)
502 {
503 	char peer_str[NODE_ID_STR_LEN] = {0,};
504 	char self_str[NODE_ID_STR_LEN] = {0,};
505 	struct tipc_link *l;
506 
507 	l = kzalloc(sizeof(*l), GFP_ATOMIC);
508 	if (!l)
509 		return false;
510 	*link = l;
511 	l->session = session;
512 
513 	/* Set link name for unicast links only */
514 	if (peer_id) {
515 		tipc_nodeid2string(self_str, tipc_own_id(net));
516 		if (strlen(self_str) > 16)
517 			sprintf(self_str, "%x", self);
518 		tipc_nodeid2string(peer_str, peer_id);
519 		if (strlen(peer_str) > 16)
520 			sprintf(peer_str, "%x", peer);
521 	}
522 	/* Peer i/f name will be completed by reset/activate message */
523 	snprintf(l->name, sizeof(l->name), "%s:%s-%s:unknown",
524 		 self_str, if_name, peer_str);
525 
526 	strcpy(l->if_name, if_name);
527 	l->addr = peer;
528 	l->peer_caps = peer_caps;
529 	l->net = net;
530 	l->in_session = false;
531 	l->bearer_id = bearer_id;
532 	l->tolerance = tolerance;
533 	if (bc_rcvlink)
534 		bc_rcvlink->tolerance = tolerance;
535 	l->net_plane = net_plane;
536 	l->advertised_mtu = mtu;
537 	l->mtu = mtu;
538 	l->priority = priority;
539 	tipc_link_set_queue_limits(l, min_win, max_win);
540 	l->ackers = 1;
541 	l->bc_sndlink = bc_sndlink;
542 	l->bc_rcvlink = bc_rcvlink;
543 	l->inputq = inputq;
544 	l->namedq = namedq;
545 	l->state = LINK_RESETTING;
546 	__skb_queue_head_init(&l->transmq);
547 	__skb_queue_head_init(&l->backlogq);
548 	__skb_queue_head_init(&l->deferdq);
549 	__skb_queue_head_init(&l->failover_deferdq);
550 	skb_queue_head_init(&l->wakeupq);
551 	skb_queue_head_init(l->inputq);
552 	return true;
553 }
554 
555 /**
556  * tipc_link_bc_create - create new link to be used for broadcast
557  * @net: pointer to associated network namespace
558  * @mtu: mtu to be used initially if no peers
559  * @min_win: minimal send window to be used by link
560  * @max_win: maximal send window to be used by link
561  * @inputq: queue to put messages ready for delivery
562  * @namedq: queue to put binding table update messages ready for delivery
563  * @link: return value, pointer to put the created link
564  * @ownnode: identity of own node
565  * @peer: node id of peer node
566  * @peer_id: 128-bit ID of peer
567  * @peer_caps: bitmap describing peer node capabilities
568  * @bc_sndlink: the namespace global link used for broadcast sending
569  *
570  * Return: true if link was created, otherwise false
571  */
572 bool tipc_link_bc_create(struct net *net, u32 ownnode, u32 peer, u8 *peer_id,
573 			 int mtu, u32 min_win, u32 max_win, u16 peer_caps,
574 			 struct sk_buff_head *inputq,
575 			 struct sk_buff_head *namedq,
576 			 struct tipc_link *bc_sndlink,
577 			 struct tipc_link **link)
578 {
579 	struct tipc_link *l;
580 
581 	if (!tipc_link_create(net, "", MAX_BEARERS, 0, 'Z', mtu, 0, min_win,
582 			      max_win, 0, ownnode, peer, NULL, peer_caps,
583 			      bc_sndlink, NULL, inputq, namedq, link))
584 		return false;
585 
586 	l = *link;
587 	if (peer_id) {
588 		char peer_str[NODE_ID_STR_LEN] = {0,};
589 
590 		tipc_nodeid2string(peer_str, peer_id);
591 		if (strlen(peer_str) > 16)
592 			sprintf(peer_str, "%x", peer);
593 		/* Broadcast receiver link name: "broadcast-link:<peer>" */
594 		snprintf(l->name, sizeof(l->name), "%s:%s", tipc_bclink_name,
595 			 peer_str);
596 	} else {
597 		strcpy(l->name, tipc_bclink_name);
598 	}
599 	trace_tipc_link_reset(l, TIPC_DUMP_ALL, "bclink created!");
600 	tipc_link_reset(l);
601 	l->state = LINK_RESET;
602 	l->ackers = 0;
603 	l->bc_rcvlink = l;
604 
605 	/* Broadcast send link is always up */
606 	if (link_is_bc_sndlink(l))
607 		l->state = LINK_ESTABLISHED;
608 
609 	/* Disable replicast if even a single peer doesn't support it */
610 	if (link_is_bc_rcvlink(l) && !(peer_caps & TIPC_BCAST_RCAST))
611 		tipc_bcast_toggle_rcast(net, false);
612 
613 	return true;
614 }
615 
616 /**
617  * tipc_link_fsm_evt - link finite state machine
618  * @l: pointer to link
619  * @evt: state machine event to be processed
620  */
621 int tipc_link_fsm_evt(struct tipc_link *l, int evt)
622 {
623 	int rc = 0;
624 	int old_state = l->state;
625 
626 	switch (l->state) {
627 	case LINK_RESETTING:
628 		switch (evt) {
629 		case LINK_PEER_RESET_EVT:
630 			l->state = LINK_PEER_RESET;
631 			break;
632 		case LINK_RESET_EVT:
633 			l->state = LINK_RESET;
634 			break;
635 		case LINK_FAILURE_EVT:
636 		case LINK_FAILOVER_BEGIN_EVT:
637 		case LINK_ESTABLISH_EVT:
638 		case LINK_FAILOVER_END_EVT:
639 		case LINK_SYNCH_BEGIN_EVT:
640 		case LINK_SYNCH_END_EVT:
641 		default:
642 			goto illegal_evt;
643 		}
644 		break;
645 	case LINK_RESET:
646 		switch (evt) {
647 		case LINK_PEER_RESET_EVT:
648 			l->state = LINK_ESTABLISHING;
649 			break;
650 		case LINK_FAILOVER_BEGIN_EVT:
651 			l->state = LINK_FAILINGOVER;
652 		case LINK_FAILURE_EVT:
653 		case LINK_RESET_EVT:
654 		case LINK_ESTABLISH_EVT:
655 		case LINK_FAILOVER_END_EVT:
656 			break;
657 		case LINK_SYNCH_BEGIN_EVT:
658 		case LINK_SYNCH_END_EVT:
659 		default:
660 			goto illegal_evt;
661 		}
662 		break;
663 	case LINK_PEER_RESET:
664 		switch (evt) {
665 		case LINK_RESET_EVT:
666 			l->state = LINK_ESTABLISHING;
667 			break;
668 		case LINK_PEER_RESET_EVT:
669 		case LINK_ESTABLISH_EVT:
670 		case LINK_FAILURE_EVT:
671 			break;
672 		case LINK_SYNCH_BEGIN_EVT:
673 		case LINK_SYNCH_END_EVT:
674 		case LINK_FAILOVER_BEGIN_EVT:
675 		case LINK_FAILOVER_END_EVT:
676 		default:
677 			goto illegal_evt;
678 		}
679 		break;
680 	case LINK_FAILINGOVER:
681 		switch (evt) {
682 		case LINK_FAILOVER_END_EVT:
683 			l->state = LINK_RESET;
684 			break;
685 		case LINK_PEER_RESET_EVT:
686 		case LINK_RESET_EVT:
687 		case LINK_ESTABLISH_EVT:
688 		case LINK_FAILURE_EVT:
689 			break;
690 		case LINK_FAILOVER_BEGIN_EVT:
691 		case LINK_SYNCH_BEGIN_EVT:
692 		case LINK_SYNCH_END_EVT:
693 		default:
694 			goto illegal_evt;
695 		}
696 		break;
697 	case LINK_ESTABLISHING:
698 		switch (evt) {
699 		case LINK_ESTABLISH_EVT:
700 			l->state = LINK_ESTABLISHED;
701 			break;
702 		case LINK_FAILOVER_BEGIN_EVT:
703 			l->state = LINK_FAILINGOVER;
704 			break;
705 		case LINK_RESET_EVT:
706 			l->state = LINK_RESET;
707 			break;
708 		case LINK_FAILURE_EVT:
709 		case LINK_PEER_RESET_EVT:
710 		case LINK_SYNCH_BEGIN_EVT:
711 		case LINK_FAILOVER_END_EVT:
712 			break;
713 		case LINK_SYNCH_END_EVT:
714 		default:
715 			goto illegal_evt;
716 		}
717 		break;
718 	case LINK_ESTABLISHED:
719 		switch (evt) {
720 		case LINK_PEER_RESET_EVT:
721 			l->state = LINK_PEER_RESET;
722 			rc |= TIPC_LINK_DOWN_EVT;
723 			break;
724 		case LINK_FAILURE_EVT:
725 			l->state = LINK_RESETTING;
726 			rc |= TIPC_LINK_DOWN_EVT;
727 			break;
728 		case LINK_RESET_EVT:
729 			l->state = LINK_RESET;
730 			break;
731 		case LINK_ESTABLISH_EVT:
732 		case LINK_SYNCH_END_EVT:
733 			break;
734 		case LINK_SYNCH_BEGIN_EVT:
735 			l->state = LINK_SYNCHING;
736 			break;
737 		case LINK_FAILOVER_BEGIN_EVT:
738 		case LINK_FAILOVER_END_EVT:
739 		default:
740 			goto illegal_evt;
741 		}
742 		break;
743 	case LINK_SYNCHING:
744 		switch (evt) {
745 		case LINK_PEER_RESET_EVT:
746 			l->state = LINK_PEER_RESET;
747 			rc |= TIPC_LINK_DOWN_EVT;
748 			break;
749 		case LINK_FAILURE_EVT:
750 			l->state = LINK_RESETTING;
751 			rc |= TIPC_LINK_DOWN_EVT;
752 			break;
753 		case LINK_RESET_EVT:
754 			l->state = LINK_RESET;
755 			break;
756 		case LINK_ESTABLISH_EVT:
757 		case LINK_SYNCH_BEGIN_EVT:
758 			break;
759 		case LINK_SYNCH_END_EVT:
760 			l->state = LINK_ESTABLISHED;
761 			break;
762 		case LINK_FAILOVER_BEGIN_EVT:
763 		case LINK_FAILOVER_END_EVT:
764 		default:
765 			goto illegal_evt;
766 		}
767 		break;
768 	default:
769 		pr_err("Unknown FSM state %x in %s\n", l->state, l->name);
770 	}
771 	trace_tipc_link_fsm(l->name, old_state, l->state, evt);
772 	return rc;
773 illegal_evt:
774 	pr_err("Illegal FSM event %x in state %x on link %s\n",
775 	       evt, l->state, l->name);
776 	trace_tipc_link_fsm(l->name, old_state, l->state, evt);
777 	return rc;
778 }
779 
780 /* link_profile_stats - update statistical profiling of traffic
781  */
782 static void link_profile_stats(struct tipc_link *l)
783 {
784 	struct sk_buff *skb;
785 	struct tipc_msg *msg;
786 	int length;
787 
788 	/* Update counters used in statistical profiling of send traffic */
789 	l->stats.accu_queue_sz += skb_queue_len(&l->transmq);
790 	l->stats.queue_sz_counts++;
791 
792 	skb = skb_peek(&l->transmq);
793 	if (!skb)
794 		return;
795 	msg = buf_msg(skb);
796 	length = msg_size(msg);
797 
798 	if (msg_user(msg) == MSG_FRAGMENTER) {
799 		if (msg_type(msg) != FIRST_FRAGMENT)
800 			return;
801 		length = msg_size(msg_inner_hdr(msg));
802 	}
803 	l->stats.msg_lengths_total += length;
804 	l->stats.msg_length_counts++;
805 	if (length <= 64)
806 		l->stats.msg_length_profile[0]++;
807 	else if (length <= 256)
808 		l->stats.msg_length_profile[1]++;
809 	else if (length <= 1024)
810 		l->stats.msg_length_profile[2]++;
811 	else if (length <= 4096)
812 		l->stats.msg_length_profile[3]++;
813 	else if (length <= 16384)
814 		l->stats.msg_length_profile[4]++;
815 	else if (length <= 32768)
816 		l->stats.msg_length_profile[5]++;
817 	else
818 		l->stats.msg_length_profile[6]++;
819 }
820 
821 /**
822  * tipc_link_too_silent - check if link is "too silent"
823  * @l: tipc link to be checked
824  *
825  * Return: true if the link 'silent_intv_cnt' is about to reach the
826  * 'abort_limit' value, otherwise false
827  */
828 bool tipc_link_too_silent(struct tipc_link *l)
829 {
830 	return (l->silent_intv_cnt + 2 > l->abort_limit);
831 }
832 
833 /* tipc_link_timeout - perform periodic task as instructed from node timeout
834  */
835 int tipc_link_timeout(struct tipc_link *l, struct sk_buff_head *xmitq)
836 {
837 	int mtyp = 0;
838 	int rc = 0;
839 	bool state = false;
840 	bool probe = false;
841 	bool setup = false;
842 	u16 bc_snt = l->bc_sndlink->snd_nxt - 1;
843 	u16 bc_acked = l->bc_rcvlink->acked;
844 	struct tipc_mon_state *mstate = &l->mon_state;
845 
846 	trace_tipc_link_timeout(l, TIPC_DUMP_NONE, " ");
847 	trace_tipc_link_too_silent(l, TIPC_DUMP_ALL, " ");
848 	switch (l->state) {
849 	case LINK_ESTABLISHED:
850 	case LINK_SYNCHING:
851 		mtyp = STATE_MSG;
852 		link_profile_stats(l);
853 		tipc_mon_get_state(l->net, l->addr, mstate, l->bearer_id);
854 		if (mstate->reset || (l->silent_intv_cnt > l->abort_limit))
855 			return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
856 		state = bc_acked != bc_snt;
857 		state |= l->bc_rcvlink->rcv_unacked;
858 		state |= l->rcv_unacked;
859 		state |= !skb_queue_empty(&l->transmq);
860 		probe = mstate->probing;
861 		probe |= l->silent_intv_cnt;
862 		if (probe || mstate->monitoring)
863 			l->silent_intv_cnt++;
864 		probe |= !skb_queue_empty(&l->deferdq);
865 		if (l->snd_nxt == l->checkpoint) {
866 			tipc_link_update_cwin(l, 0, 0);
867 			probe = true;
868 		}
869 		l->checkpoint = l->snd_nxt;
870 		break;
871 	case LINK_RESET:
872 		setup = l->rst_cnt++ <= 4;
873 		setup |= !(l->rst_cnt % 16);
874 		mtyp = RESET_MSG;
875 		break;
876 	case LINK_ESTABLISHING:
877 		setup = true;
878 		mtyp = ACTIVATE_MSG;
879 		break;
880 	case LINK_PEER_RESET:
881 	case LINK_RESETTING:
882 	case LINK_FAILINGOVER:
883 		break;
884 	default:
885 		break;
886 	}
887 
888 	if (state || probe || setup)
889 		tipc_link_build_proto_msg(l, mtyp, probe, 0, 0, 0, 0, xmitq);
890 
891 	return rc;
892 }
893 
894 /**
895  * link_schedule_user - schedule a message sender for wakeup after congestion
896  * @l: congested link
897  * @hdr: header of message that is being sent
898  * Create pseudo msg to send back to user when congestion abates
899  */
900 static int link_schedule_user(struct tipc_link *l, struct tipc_msg *hdr)
901 {
902 	u32 dnode = tipc_own_addr(l->net);
903 	u32 dport = msg_origport(hdr);
904 	struct sk_buff *skb;
905 
906 	/* Create and schedule wakeup pseudo message */
907 	skb = tipc_msg_create(SOCK_WAKEUP, 0, INT_H_SIZE, 0,
908 			      dnode, l->addr, dport, 0, 0);
909 	if (!skb)
910 		return -ENOBUFS;
911 	msg_set_dest_droppable(buf_msg(skb), true);
912 	TIPC_SKB_CB(skb)->chain_imp = msg_importance(hdr);
913 	skb_queue_tail(&l->wakeupq, skb);
914 	l->stats.link_congs++;
915 	trace_tipc_link_conges(l, TIPC_DUMP_ALL, "wakeup scheduled!");
916 	return -ELINKCONG;
917 }
918 
919 /**
920  * link_prepare_wakeup - prepare users for wakeup after congestion
921  * @l: congested link
922  * Wake up a number of waiting users, as permitted by available space
923  * in the send queue
924  */
925 static void link_prepare_wakeup(struct tipc_link *l)
926 {
927 	struct sk_buff_head *wakeupq = &l->wakeupq;
928 	struct sk_buff_head *inputq = l->inputq;
929 	struct sk_buff *skb, *tmp;
930 	struct sk_buff_head tmpq;
931 	int avail[5] = {0,};
932 	int imp = 0;
933 
934 	__skb_queue_head_init(&tmpq);
935 
936 	for (; imp <= TIPC_SYSTEM_IMPORTANCE; imp++)
937 		avail[imp] = l->backlog[imp].limit - l->backlog[imp].len;
938 
939 	skb_queue_walk_safe(wakeupq, skb, tmp) {
940 		imp = TIPC_SKB_CB(skb)->chain_imp;
941 		if (avail[imp] <= 0)
942 			continue;
943 		avail[imp]--;
944 		__skb_unlink(skb, wakeupq);
945 		__skb_queue_tail(&tmpq, skb);
946 	}
947 
948 	spin_lock_bh(&inputq->lock);
949 	skb_queue_splice_tail(&tmpq, inputq);
950 	spin_unlock_bh(&inputq->lock);
951 
952 }
953 
954 /**
955  * tipc_link_set_skb_retransmit_time - set the time at which retransmission of
956  *                                     the given skb should be next attempted
957  * @skb: skb to set a future retransmission time for
958  * @l: link the skb will be transmitted on
959  */
960 static void tipc_link_set_skb_retransmit_time(struct sk_buff *skb,
961 					      struct tipc_link *l)
962 {
963 	if (link_is_bc_sndlink(l))
964 		TIPC_SKB_CB(skb)->nxt_retr = TIPC_BC_RETR_LIM;
965 	else
966 		TIPC_SKB_CB(skb)->nxt_retr = TIPC_UC_RETR_TIME;
967 }
968 
969 void tipc_link_reset(struct tipc_link *l)
970 {
971 	struct sk_buff_head list;
972 	u32 imp;
973 
974 	__skb_queue_head_init(&list);
975 
976 	l->in_session = false;
977 	/* Force re-synch of peer session number before establishing */
978 	l->peer_session--;
979 	l->session++;
980 	l->mtu = l->advertised_mtu;
981 
982 	spin_lock_bh(&l->wakeupq.lock);
983 	skb_queue_splice_init(&l->wakeupq, &list);
984 	spin_unlock_bh(&l->wakeupq.lock);
985 
986 	spin_lock_bh(&l->inputq->lock);
987 	skb_queue_splice_init(&list, l->inputq);
988 	spin_unlock_bh(&l->inputq->lock);
989 
990 	__skb_queue_purge(&l->transmq);
991 	__skb_queue_purge(&l->deferdq);
992 	__skb_queue_purge(&l->backlogq);
993 	__skb_queue_purge(&l->failover_deferdq);
994 	for (imp = 0; imp <= TIPC_SYSTEM_IMPORTANCE; imp++) {
995 		l->backlog[imp].len = 0;
996 		l->backlog[imp].target_bskb = NULL;
997 	}
998 	kfree_skb(l->reasm_buf);
999 	kfree_skb(l->reasm_tnlmsg);
1000 	kfree_skb(l->failover_reasm_skb);
1001 	l->reasm_buf = NULL;
1002 	l->reasm_tnlmsg = NULL;
1003 	l->failover_reasm_skb = NULL;
1004 	l->rcv_unacked = 0;
1005 	l->snd_nxt = 1;
1006 	l->rcv_nxt = 1;
1007 	l->snd_nxt_state = 1;
1008 	l->rcv_nxt_state = 1;
1009 	l->acked = 0;
1010 	l->last_gap = 0;
1011 	kfree(l->last_ga);
1012 	l->last_ga = NULL;
1013 	l->silent_intv_cnt = 0;
1014 	l->rst_cnt = 0;
1015 	l->bc_peer_is_up = false;
1016 	memset(&l->mon_state, 0, sizeof(l->mon_state));
1017 	tipc_link_reset_stats(l);
1018 }
1019 
1020 /**
1021  * tipc_link_xmit(): enqueue buffer list according to queue situation
1022  * @l: link to use
1023  * @list: chain of buffers containing message
1024  * @xmitq: returned list of packets to be sent by caller
1025  *
1026  * Consumes the buffer chain.
1027  * Messages at TIPC_SYSTEM_IMPORTANCE are always accepted
1028  * Return: 0 if success, or errno: -ELINKCONG, -EMSGSIZE or -ENOBUFS
1029  */
1030 int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *list,
1031 		   struct sk_buff_head *xmitq)
1032 {
1033 	struct tipc_msg *hdr = buf_msg(skb_peek(list));
1034 	struct sk_buff_head *backlogq = &l->backlogq;
1035 	struct sk_buff_head *transmq = &l->transmq;
1036 	struct sk_buff *skb, *_skb;
1037 	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
1038 	u16 ack = l->rcv_nxt - 1;
1039 	u16 seqno = l->snd_nxt;
1040 	int pkt_cnt = skb_queue_len(list);
1041 	int imp = msg_importance(hdr);
1042 	unsigned int mss = tipc_link_mss(l);
1043 	unsigned int cwin = l->window;
1044 	unsigned int mtu = l->mtu;
1045 	bool new_bundle;
1046 	int rc = 0;
1047 
1048 	if (unlikely(msg_size(hdr) > mtu)) {
1049 		pr_warn("Too large msg, purging xmit list %d %d %d %d %d!\n",
1050 			skb_queue_len(list), msg_user(hdr),
1051 			msg_type(hdr), msg_size(hdr), mtu);
1052 		__skb_queue_purge(list);
1053 		return -EMSGSIZE;
1054 	}
1055 
1056 	/* Allow oversubscription of one data msg per source at congestion */
1057 	if (unlikely(l->backlog[imp].len >= l->backlog[imp].limit)) {
1058 		if (imp == TIPC_SYSTEM_IMPORTANCE) {
1059 			pr_warn("%s<%s>, link overflow", link_rst_msg, l->name);
1060 			return -ENOBUFS;
1061 		}
1062 		rc = link_schedule_user(l, hdr);
1063 	}
1064 
1065 	if (pkt_cnt > 1) {
1066 		l->stats.sent_fragmented++;
1067 		l->stats.sent_fragments += pkt_cnt;
1068 	}
1069 
1070 	/* Prepare each packet for sending, and add to relevant queue: */
1071 	while ((skb = __skb_dequeue(list))) {
1072 		if (likely(skb_queue_len(transmq) < cwin)) {
1073 			hdr = buf_msg(skb);
1074 			msg_set_seqno(hdr, seqno);
1075 			msg_set_ack(hdr, ack);
1076 			msg_set_bcast_ack(hdr, bc_ack);
1077 			_skb = skb_clone(skb, GFP_ATOMIC);
1078 			if (!_skb) {
1079 				kfree_skb(skb);
1080 				__skb_queue_purge(list);
1081 				return -ENOBUFS;
1082 			}
1083 			__skb_queue_tail(transmq, skb);
1084 			tipc_link_set_skb_retransmit_time(skb, l);
1085 			__skb_queue_tail(xmitq, _skb);
1086 			TIPC_SKB_CB(skb)->ackers = l->ackers;
1087 			l->rcv_unacked = 0;
1088 			l->stats.sent_pkts++;
1089 			seqno++;
1090 			continue;
1091 		}
1092 		if (tipc_msg_try_bundle(l->backlog[imp].target_bskb, &skb,
1093 					mss, l->addr, &new_bundle)) {
1094 			if (skb) {
1095 				/* Keep a ref. to the skb for next try */
1096 				l->backlog[imp].target_bskb = skb;
1097 				l->backlog[imp].len++;
1098 				__skb_queue_tail(backlogq, skb);
1099 			} else {
1100 				if (new_bundle) {
1101 					l->stats.sent_bundles++;
1102 					l->stats.sent_bundled++;
1103 				}
1104 				l->stats.sent_bundled++;
1105 			}
1106 			continue;
1107 		}
1108 		l->backlog[imp].target_bskb = NULL;
1109 		l->backlog[imp].len += (1 + skb_queue_len(list));
1110 		__skb_queue_tail(backlogq, skb);
1111 		skb_queue_splice_tail_init(list, backlogq);
1112 	}
1113 	l->snd_nxt = seqno;
1114 	return rc;
1115 }
1116 
1117 static void tipc_link_update_cwin(struct tipc_link *l, int released,
1118 				  bool retransmitted)
1119 {
1120 	int bklog_len = skb_queue_len(&l->backlogq);
1121 	struct sk_buff_head *txq = &l->transmq;
1122 	int txq_len = skb_queue_len(txq);
1123 	u16 cwin = l->window;
1124 
1125 	/* Enter fast recovery */
1126 	if (unlikely(retransmitted)) {
1127 		l->ssthresh = max_t(u16, l->window / 2, 300);
1128 		l->window = min_t(u16, l->ssthresh, l->window);
1129 		return;
1130 	}
1131 	/* Enter slow start */
1132 	if (unlikely(!released)) {
1133 		l->ssthresh = max_t(u16, l->window / 2, 300);
1134 		l->window = l->min_win;
1135 		return;
1136 	}
1137 	/* Don't increase window if no pressure on the transmit queue */
1138 	if (txq_len + bklog_len < cwin)
1139 		return;
1140 
1141 	/* Don't increase window if there are holes the transmit queue */
1142 	if (txq_len && l->snd_nxt - buf_seqno(skb_peek(txq)) != txq_len)
1143 		return;
1144 
1145 	l->cong_acks += released;
1146 
1147 	/* Slow start  */
1148 	if (cwin <= l->ssthresh) {
1149 		l->window = min_t(u16, cwin + released, l->max_win);
1150 		return;
1151 	}
1152 	/* Congestion avoidance */
1153 	if (l->cong_acks < cwin)
1154 		return;
1155 	l->window = min_t(u16, ++cwin, l->max_win);
1156 	l->cong_acks = 0;
1157 }
1158 
1159 static void tipc_link_advance_backlog(struct tipc_link *l,
1160 				      struct sk_buff_head *xmitq)
1161 {
1162 	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
1163 	struct sk_buff_head *txq = &l->transmq;
1164 	struct sk_buff *skb, *_skb;
1165 	u16 ack = l->rcv_nxt - 1;
1166 	u16 seqno = l->snd_nxt;
1167 	struct tipc_msg *hdr;
1168 	u16 cwin = l->window;
1169 	u32 imp;
1170 
1171 	while (skb_queue_len(txq) < cwin) {
1172 		skb = skb_peek(&l->backlogq);
1173 		if (!skb)
1174 			break;
1175 		_skb = skb_clone(skb, GFP_ATOMIC);
1176 		if (!_skb)
1177 			break;
1178 		__skb_dequeue(&l->backlogq);
1179 		hdr = buf_msg(skb);
1180 		imp = msg_importance(hdr);
1181 		l->backlog[imp].len--;
1182 		if (unlikely(skb == l->backlog[imp].target_bskb))
1183 			l->backlog[imp].target_bskb = NULL;
1184 		__skb_queue_tail(&l->transmq, skb);
1185 		tipc_link_set_skb_retransmit_time(skb, l);
1186 
1187 		__skb_queue_tail(xmitq, _skb);
1188 		TIPC_SKB_CB(skb)->ackers = l->ackers;
1189 		msg_set_seqno(hdr, seqno);
1190 		msg_set_ack(hdr, ack);
1191 		msg_set_bcast_ack(hdr, bc_ack);
1192 		l->rcv_unacked = 0;
1193 		l->stats.sent_pkts++;
1194 		seqno++;
1195 	}
1196 	l->snd_nxt = seqno;
1197 }
1198 
1199 /**
1200  * link_retransmit_failure() - Detect repeated retransmit failures
1201  * @l: tipc link sender
1202  * @r: tipc link receiver (= l in case of unicast)
1203  * @rc: returned code
1204  *
1205  * Return: true if the repeated retransmit failures happens, otherwise
1206  * false
1207  */
1208 static bool link_retransmit_failure(struct tipc_link *l, struct tipc_link *r,
1209 				    int *rc)
1210 {
1211 	struct sk_buff *skb = skb_peek(&l->transmq);
1212 	struct tipc_msg *hdr;
1213 
1214 	if (!skb)
1215 		return false;
1216 
1217 	if (!TIPC_SKB_CB(skb)->retr_cnt)
1218 		return false;
1219 
1220 	if (!time_after(jiffies, TIPC_SKB_CB(skb)->retr_stamp +
1221 			msecs_to_jiffies(r->tolerance * 10)))
1222 		return false;
1223 
1224 	hdr = buf_msg(skb);
1225 	if (link_is_bc_sndlink(l) && !less(r->acked, msg_seqno(hdr)))
1226 		return false;
1227 
1228 	pr_warn("Retransmission failure on link <%s>\n", l->name);
1229 	link_print(l, "State of link ");
1230 	pr_info("Failed msg: usr %u, typ %u, len %u, err %u\n",
1231 		msg_user(hdr), msg_type(hdr), msg_size(hdr), msg_errcode(hdr));
1232 	pr_info("sqno %u, prev: %x, dest: %x\n",
1233 		msg_seqno(hdr), msg_prevnode(hdr), msg_destnode(hdr));
1234 	pr_info("retr_stamp %d, retr_cnt %d\n",
1235 		jiffies_to_msecs(TIPC_SKB_CB(skb)->retr_stamp),
1236 		TIPC_SKB_CB(skb)->retr_cnt);
1237 
1238 	trace_tipc_list_dump(&l->transmq, true, "retrans failure!");
1239 	trace_tipc_link_dump(l, TIPC_DUMP_NONE, "retrans failure!");
1240 	trace_tipc_link_dump(r, TIPC_DUMP_NONE, "retrans failure!");
1241 
1242 	if (link_is_bc_sndlink(l)) {
1243 		r->state = LINK_RESET;
1244 		*rc |= TIPC_LINK_DOWN_EVT;
1245 	} else {
1246 		*rc |= tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1247 	}
1248 
1249 	return true;
1250 }
1251 
1252 /* tipc_data_input - deliver data and name distr msgs to upper layer
1253  *
1254  * Consumes buffer if message is of right type
1255  * Node lock must be held
1256  */
1257 static bool tipc_data_input(struct tipc_link *l, struct sk_buff *skb,
1258 			    struct sk_buff_head *inputq)
1259 {
1260 	struct sk_buff_head *mc_inputq = l->bc_rcvlink->inputq;
1261 	struct tipc_msg *hdr = buf_msg(skb);
1262 
1263 	switch (msg_user(hdr)) {
1264 	case TIPC_LOW_IMPORTANCE:
1265 	case TIPC_MEDIUM_IMPORTANCE:
1266 	case TIPC_HIGH_IMPORTANCE:
1267 	case TIPC_CRITICAL_IMPORTANCE:
1268 		if (unlikely(msg_in_group(hdr) || msg_mcast(hdr))) {
1269 			skb_queue_tail(mc_inputq, skb);
1270 			return true;
1271 		}
1272 		fallthrough;
1273 	case CONN_MANAGER:
1274 		skb_queue_tail(inputq, skb);
1275 		return true;
1276 	case GROUP_PROTOCOL:
1277 		skb_queue_tail(mc_inputq, skb);
1278 		return true;
1279 	case NAME_DISTRIBUTOR:
1280 		l->bc_rcvlink->state = LINK_ESTABLISHED;
1281 		skb_queue_tail(l->namedq, skb);
1282 		return true;
1283 	case MSG_BUNDLER:
1284 	case TUNNEL_PROTOCOL:
1285 	case MSG_FRAGMENTER:
1286 	case BCAST_PROTOCOL:
1287 		return false;
1288 #ifdef CONFIG_TIPC_CRYPTO
1289 	case MSG_CRYPTO:
1290 		tipc_crypto_msg_rcv(l->net, skb);
1291 		return true;
1292 #endif
1293 	default:
1294 		pr_warn("Dropping received illegal msg type\n");
1295 		kfree_skb(skb);
1296 		return true;
1297 	}
1298 }
1299 
1300 /* tipc_link_input - process packet that has passed link protocol check
1301  *
1302  * Consumes buffer
1303  */
1304 static int tipc_link_input(struct tipc_link *l, struct sk_buff *skb,
1305 			   struct sk_buff_head *inputq,
1306 			   struct sk_buff **reasm_skb)
1307 {
1308 	struct tipc_msg *hdr = buf_msg(skb);
1309 	struct sk_buff *iskb;
1310 	struct sk_buff_head tmpq;
1311 	int usr = msg_user(hdr);
1312 	int pos = 0;
1313 
1314 	if (usr == MSG_BUNDLER) {
1315 		skb_queue_head_init(&tmpq);
1316 		l->stats.recv_bundles++;
1317 		l->stats.recv_bundled += msg_msgcnt(hdr);
1318 		while (tipc_msg_extract(skb, &iskb, &pos))
1319 			tipc_data_input(l, iskb, &tmpq);
1320 		tipc_skb_queue_splice_tail(&tmpq, inputq);
1321 		return 0;
1322 	} else if (usr == MSG_FRAGMENTER) {
1323 		l->stats.recv_fragments++;
1324 		if (tipc_buf_append(reasm_skb, &skb)) {
1325 			l->stats.recv_fragmented++;
1326 			tipc_data_input(l, skb, inputq);
1327 		} else if (!*reasm_skb && !link_is_bc_rcvlink(l)) {
1328 			pr_warn_ratelimited("Unable to build fragment list\n");
1329 			return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1330 		}
1331 		return 0;
1332 	} else if (usr == BCAST_PROTOCOL) {
1333 		tipc_bcast_lock(l->net);
1334 		tipc_link_bc_init_rcv(l->bc_rcvlink, hdr);
1335 		tipc_bcast_unlock(l->net);
1336 	}
1337 
1338 	kfree_skb(skb);
1339 	return 0;
1340 }
1341 
1342 /* tipc_link_tnl_rcv() - receive TUNNEL_PROTOCOL message, drop or process the
1343  *			 inner message along with the ones in the old link's
1344  *			 deferdq
1345  * @l: tunnel link
1346  * @skb: TUNNEL_PROTOCOL message
1347  * @inputq: queue to put messages ready for delivery
1348  */
1349 static int tipc_link_tnl_rcv(struct tipc_link *l, struct sk_buff *skb,
1350 			     struct sk_buff_head *inputq)
1351 {
1352 	struct sk_buff **reasm_skb = &l->failover_reasm_skb;
1353 	struct sk_buff **reasm_tnlmsg = &l->reasm_tnlmsg;
1354 	struct sk_buff_head *fdefq = &l->failover_deferdq;
1355 	struct tipc_msg *hdr = buf_msg(skb);
1356 	struct sk_buff *iskb;
1357 	int ipos = 0;
1358 	int rc = 0;
1359 	u16 seqno;
1360 
1361 	if (msg_type(hdr) == SYNCH_MSG) {
1362 		kfree_skb(skb);
1363 		return 0;
1364 	}
1365 
1366 	/* Not a fragment? */
1367 	if (likely(!msg_nof_fragms(hdr))) {
1368 		if (unlikely(!tipc_msg_extract(skb, &iskb, &ipos))) {
1369 			pr_warn_ratelimited("Unable to extract msg, defq: %d\n",
1370 					    skb_queue_len(fdefq));
1371 			return 0;
1372 		}
1373 		kfree_skb(skb);
1374 	} else {
1375 		/* Set fragment type for buf_append */
1376 		if (msg_fragm_no(hdr) == 1)
1377 			msg_set_type(hdr, FIRST_FRAGMENT);
1378 		else if (msg_fragm_no(hdr) < msg_nof_fragms(hdr))
1379 			msg_set_type(hdr, FRAGMENT);
1380 		else
1381 			msg_set_type(hdr, LAST_FRAGMENT);
1382 
1383 		if (!tipc_buf_append(reasm_tnlmsg, &skb)) {
1384 			/* Successful but non-complete reassembly? */
1385 			if (*reasm_tnlmsg || link_is_bc_rcvlink(l))
1386 				return 0;
1387 			pr_warn_ratelimited("Unable to reassemble tunnel msg\n");
1388 			return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1389 		}
1390 		iskb = skb;
1391 	}
1392 
1393 	do {
1394 		seqno = buf_seqno(iskb);
1395 		if (unlikely(less(seqno, l->drop_point))) {
1396 			kfree_skb(iskb);
1397 			continue;
1398 		}
1399 		if (unlikely(seqno != l->drop_point)) {
1400 			__tipc_skb_queue_sorted(fdefq, seqno, iskb);
1401 			continue;
1402 		}
1403 
1404 		l->drop_point++;
1405 		if (!tipc_data_input(l, iskb, inputq))
1406 			rc |= tipc_link_input(l, iskb, inputq, reasm_skb);
1407 		if (unlikely(rc))
1408 			break;
1409 	} while ((iskb = __tipc_skb_dequeue(fdefq, l->drop_point)));
1410 
1411 	return rc;
1412 }
1413 
1414 /**
1415  * tipc_get_gap_ack_blks - get Gap ACK blocks from PROTOCOL/STATE_MSG
1416  * @ga: returned pointer to the Gap ACK blocks if any
1417  * @l: the tipc link
1418  * @hdr: the PROTOCOL/STATE_MSG header
1419  * @uc: desired Gap ACK blocks type, i.e. unicast (= 1) or broadcast (= 0)
1420  *
1421  * Return: the total Gap ACK blocks size
1422  */
1423 u16 tipc_get_gap_ack_blks(struct tipc_gap_ack_blks **ga, struct tipc_link *l,
1424 			  struct tipc_msg *hdr, bool uc)
1425 {
1426 	struct tipc_gap_ack_blks *p;
1427 	u16 sz = 0;
1428 
1429 	/* Does peer support the Gap ACK blocks feature? */
1430 	if (l->peer_caps & TIPC_GAP_ACK_BLOCK) {
1431 		p = (struct tipc_gap_ack_blks *)msg_data(hdr);
1432 		sz = ntohs(p->len);
1433 		/* Sanity check */
1434 		if (sz == struct_size(p, gacks, p->ugack_cnt + p->bgack_cnt)) {
1435 			/* Good, check if the desired type exists */
1436 			if ((uc && p->ugack_cnt) || (!uc && p->bgack_cnt))
1437 				goto ok;
1438 		/* Backward compatible: peer might not support bc, but uc? */
1439 		} else if (uc && sz == struct_size(p, gacks, p->ugack_cnt)) {
1440 			if (p->ugack_cnt) {
1441 				p->bgack_cnt = 0;
1442 				goto ok;
1443 			}
1444 		}
1445 	}
1446 	/* Other cases: ignore! */
1447 	p = NULL;
1448 
1449 ok:
1450 	*ga = p;
1451 	return sz;
1452 }
1453 
1454 static u8 __tipc_build_gap_ack_blks(struct tipc_gap_ack_blks *ga,
1455 				    struct tipc_link *l, u8 start_index)
1456 {
1457 	struct tipc_gap_ack *gacks = &ga->gacks[start_index];
1458 	struct sk_buff *skb = skb_peek(&l->deferdq);
1459 	u16 expect, seqno = 0;
1460 	u8 n = 0;
1461 
1462 	if (!skb)
1463 		return 0;
1464 
1465 	expect = buf_seqno(skb);
1466 	skb_queue_walk(&l->deferdq, skb) {
1467 		seqno = buf_seqno(skb);
1468 		if (unlikely(more(seqno, expect))) {
1469 			gacks[n].ack = htons(expect - 1);
1470 			gacks[n].gap = htons(seqno - expect);
1471 			if (++n >= MAX_GAP_ACK_BLKS / 2) {
1472 				pr_info_ratelimited("Gacks on %s: %d, ql: %d!\n",
1473 						    l->name, n,
1474 						    skb_queue_len(&l->deferdq));
1475 				return n;
1476 			}
1477 		} else if (unlikely(less(seqno, expect))) {
1478 			pr_warn("Unexpected skb in deferdq!\n");
1479 			continue;
1480 		}
1481 		expect = seqno + 1;
1482 	}
1483 
1484 	/* last block */
1485 	gacks[n].ack = htons(seqno);
1486 	gacks[n].gap = 0;
1487 	n++;
1488 	return n;
1489 }
1490 
1491 /* tipc_build_gap_ack_blks - build Gap ACK blocks
1492  * @l: tipc unicast link
1493  * @hdr: the tipc message buffer to store the Gap ACK blocks after built
1494  *
1495  * The function builds Gap ACK blocks for both the unicast & broadcast receiver
1496  * links of a certain peer, the buffer after built has the network data format
1497  * as found at the struct tipc_gap_ack_blks definition.
1498  *
1499  * returns the actual allocated memory size
1500  */
1501 static u16 tipc_build_gap_ack_blks(struct tipc_link *l, struct tipc_msg *hdr)
1502 {
1503 	struct tipc_link *bcl = l->bc_rcvlink;
1504 	struct tipc_gap_ack_blks *ga;
1505 	u16 len;
1506 
1507 	ga = (struct tipc_gap_ack_blks *)msg_data(hdr);
1508 
1509 	/* Start with broadcast link first */
1510 	tipc_bcast_lock(bcl->net);
1511 	msg_set_bcast_ack(hdr, bcl->rcv_nxt - 1);
1512 	msg_set_bc_gap(hdr, link_bc_rcv_gap(bcl));
1513 	ga->bgack_cnt = __tipc_build_gap_ack_blks(ga, bcl, 0);
1514 	tipc_bcast_unlock(bcl->net);
1515 
1516 	/* Now for unicast link, but an explicit NACK only (???) */
1517 	ga->ugack_cnt = (msg_seq_gap(hdr)) ?
1518 			__tipc_build_gap_ack_blks(ga, l, ga->bgack_cnt) : 0;
1519 
1520 	/* Total len */
1521 	len = struct_size(ga, gacks, ga->bgack_cnt + ga->ugack_cnt);
1522 	ga->len = htons(len);
1523 	return len;
1524 }
1525 
1526 /* tipc_link_advance_transmq - advance TIPC link transmq queue by releasing
1527  *			       acked packets, also doing retransmissions if
1528  *			       gaps found
1529  * @l: tipc link with transmq queue to be advanced
1530  * @r: tipc link "receiver" i.e. in case of broadcast (= "l" if unicast)
1531  * @acked: seqno of last packet acked by peer without any gaps before
1532  * @gap: # of gap packets
1533  * @ga: buffer pointer to Gap ACK blocks from peer
1534  * @xmitq: queue for accumulating the retransmitted packets if any
1535  * @retransmitted: returned boolean value if a retransmission is really issued
1536  * @rc: returned code e.g. TIPC_LINK_DOWN_EVT if a repeated retransmit failures
1537  *      happens (- unlikely case)
1538  *
1539  * Return: the number of packets released from the link transmq
1540  */
1541 static int tipc_link_advance_transmq(struct tipc_link *l, struct tipc_link *r,
1542 				     u16 acked, u16 gap,
1543 				     struct tipc_gap_ack_blks *ga,
1544 				     struct sk_buff_head *xmitq,
1545 				     bool *retransmitted, int *rc)
1546 {
1547 	struct tipc_gap_ack_blks *last_ga = r->last_ga, *this_ga = NULL;
1548 	struct tipc_gap_ack *gacks = NULL;
1549 	struct sk_buff *skb, *_skb, *tmp;
1550 	struct tipc_msg *hdr;
1551 	u32 qlen = skb_queue_len(&l->transmq);
1552 	u16 nacked = acked, ngap = gap, gack_cnt = 0;
1553 	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
1554 	u16 ack = l->rcv_nxt - 1;
1555 	u16 seqno, n = 0;
1556 	u16 end = r->acked, start = end, offset = r->last_gap;
1557 	u16 si = (last_ga) ? last_ga->start_index : 0;
1558 	bool is_uc = !link_is_bc_sndlink(l);
1559 	bool bc_has_acked = false;
1560 
1561 	trace_tipc_link_retrans(r, acked + 1, acked + gap, &l->transmq);
1562 
1563 	/* Determine Gap ACK blocks if any for the particular link */
1564 	if (ga && is_uc) {
1565 		/* Get the Gap ACKs, uc part */
1566 		gack_cnt = ga->ugack_cnt;
1567 		gacks = &ga->gacks[ga->bgack_cnt];
1568 	} else if (ga) {
1569 		/* Copy the Gap ACKs, bc part, for later renewal if needed */
1570 		this_ga = kmemdup(ga, struct_size(ga, gacks, ga->bgack_cnt),
1571 				  GFP_ATOMIC);
1572 		if (likely(this_ga)) {
1573 			this_ga->start_index = 0;
1574 			/* Start with the bc Gap ACKs */
1575 			gack_cnt = this_ga->bgack_cnt;
1576 			gacks = &this_ga->gacks[0];
1577 		} else {
1578 			/* Hmm, we can get in trouble..., simply ignore it */
1579 			pr_warn_ratelimited("Ignoring bc Gap ACKs, no memory\n");
1580 		}
1581 	}
1582 
1583 	/* Advance the link transmq */
1584 	skb_queue_walk_safe(&l->transmq, skb, tmp) {
1585 		seqno = buf_seqno(skb);
1586 
1587 next_gap_ack:
1588 		if (less_eq(seqno, nacked)) {
1589 			if (is_uc)
1590 				goto release;
1591 			/* Skip packets peer has already acked */
1592 			if (!more(seqno, r->acked))
1593 				continue;
1594 			/* Get the next of last Gap ACK blocks */
1595 			while (more(seqno, end)) {
1596 				if (!last_ga || si >= last_ga->bgack_cnt)
1597 					break;
1598 				start = end + offset + 1;
1599 				end = ntohs(last_ga->gacks[si].ack);
1600 				offset = ntohs(last_ga->gacks[si].gap);
1601 				si++;
1602 				WARN_ONCE(more(start, end) ||
1603 					  (!offset &&
1604 					   si < last_ga->bgack_cnt) ||
1605 					  si > MAX_GAP_ACK_BLKS,
1606 					  "Corrupted Gap ACK: %d %d %d %d %d\n",
1607 					  start, end, offset, si,
1608 					  last_ga->bgack_cnt);
1609 			}
1610 			/* Check against the last Gap ACK block */
1611 			if (in_range(seqno, start, end))
1612 				continue;
1613 			/* Update/release the packet peer is acking */
1614 			bc_has_acked = true;
1615 			if (--TIPC_SKB_CB(skb)->ackers)
1616 				continue;
1617 release:
1618 			/* release skb */
1619 			__skb_unlink(skb, &l->transmq);
1620 			kfree_skb(skb);
1621 		} else if (less_eq(seqno, nacked + ngap)) {
1622 			/* First gap: check if repeated retrans failures? */
1623 			if (unlikely(seqno == acked + 1 &&
1624 				     link_retransmit_failure(l, r, rc))) {
1625 				/* Ignore this bc Gap ACKs if any */
1626 				kfree(this_ga);
1627 				this_ga = NULL;
1628 				break;
1629 			}
1630 			/* retransmit skb if unrestricted*/
1631 			if (time_before(jiffies, TIPC_SKB_CB(skb)->nxt_retr))
1632 				continue;
1633 			tipc_link_set_skb_retransmit_time(skb, l);
1634 			_skb = pskb_copy(skb, GFP_ATOMIC);
1635 			if (!_skb)
1636 				continue;
1637 			hdr = buf_msg(_skb);
1638 			msg_set_ack(hdr, ack);
1639 			msg_set_bcast_ack(hdr, bc_ack);
1640 			_skb->priority = TC_PRIO_CONTROL;
1641 			__skb_queue_tail(xmitq, _skb);
1642 			l->stats.retransmitted++;
1643 			if (!is_uc)
1644 				r->stats.retransmitted++;
1645 			*retransmitted = true;
1646 			/* Increase actual retrans counter & mark first time */
1647 			if (!TIPC_SKB_CB(skb)->retr_cnt++)
1648 				TIPC_SKB_CB(skb)->retr_stamp = jiffies;
1649 		} else {
1650 			/* retry with Gap ACK blocks if any */
1651 			if (n >= gack_cnt)
1652 				break;
1653 			nacked = ntohs(gacks[n].ack);
1654 			ngap = ntohs(gacks[n].gap);
1655 			n++;
1656 			goto next_gap_ack;
1657 		}
1658 	}
1659 
1660 	/* Renew last Gap ACK blocks for bc if needed */
1661 	if (bc_has_acked) {
1662 		if (this_ga) {
1663 			kfree(last_ga);
1664 			r->last_ga = this_ga;
1665 			r->last_gap = gap;
1666 		} else if (last_ga) {
1667 			if (less(acked, start)) {
1668 				si--;
1669 				offset = start - acked - 1;
1670 			} else if (less(acked, end)) {
1671 				acked = end;
1672 			}
1673 			if (si < last_ga->bgack_cnt) {
1674 				last_ga->start_index = si;
1675 				r->last_gap = offset;
1676 			} else {
1677 				kfree(last_ga);
1678 				r->last_ga = NULL;
1679 				r->last_gap = 0;
1680 			}
1681 		} else {
1682 			r->last_gap = 0;
1683 		}
1684 		r->acked = acked;
1685 	} else {
1686 		kfree(this_ga);
1687 	}
1688 
1689 	return qlen - skb_queue_len(&l->transmq);
1690 }
1691 
1692 /* tipc_link_build_state_msg: prepare link state message for transmission
1693  *
1694  * Note that sending of broadcast ack is coordinated among nodes, to reduce
1695  * risk of ack storms towards the sender
1696  */
1697 int tipc_link_build_state_msg(struct tipc_link *l, struct sk_buff_head *xmitq)
1698 {
1699 	if (!l)
1700 		return 0;
1701 
1702 	/* Broadcast ACK must be sent via a unicast link => defer to caller */
1703 	if (link_is_bc_rcvlink(l)) {
1704 		if (((l->rcv_nxt ^ tipc_own_addr(l->net)) & 0xf) != 0xf)
1705 			return 0;
1706 		l->rcv_unacked = 0;
1707 
1708 		/* Use snd_nxt to store peer's snd_nxt in broadcast rcv link */
1709 		l->snd_nxt = l->rcv_nxt;
1710 		return TIPC_LINK_SND_STATE;
1711 	}
1712 	/* Unicast ACK */
1713 	l->rcv_unacked = 0;
1714 	l->stats.sent_acks++;
1715 	tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, 0, 0, xmitq);
1716 	return 0;
1717 }
1718 
1719 /* tipc_link_build_reset_msg: prepare link RESET or ACTIVATE message
1720  */
1721 void tipc_link_build_reset_msg(struct tipc_link *l, struct sk_buff_head *xmitq)
1722 {
1723 	int mtyp = RESET_MSG;
1724 	struct sk_buff *skb;
1725 
1726 	if (l->state == LINK_ESTABLISHING)
1727 		mtyp = ACTIVATE_MSG;
1728 
1729 	tipc_link_build_proto_msg(l, mtyp, 0, 0, 0, 0, 0, xmitq);
1730 
1731 	/* Inform peer that this endpoint is going down if applicable */
1732 	skb = skb_peek_tail(xmitq);
1733 	if (skb && (l->state == LINK_RESET))
1734 		msg_set_peer_stopping(buf_msg(skb), 1);
1735 }
1736 
1737 /* tipc_link_build_nack_msg: prepare link nack message for transmission
1738  * Note that sending of broadcast NACK is coordinated among nodes, to
1739  * reduce the risk of NACK storms towards the sender
1740  */
1741 static int tipc_link_build_nack_msg(struct tipc_link *l,
1742 				    struct sk_buff_head *xmitq)
1743 {
1744 	u32 def_cnt = ++l->stats.deferred_recv;
1745 	struct sk_buff_head *dfq = &l->deferdq;
1746 	u32 defq_len = skb_queue_len(dfq);
1747 	int match1, match2;
1748 
1749 	if (link_is_bc_rcvlink(l)) {
1750 		match1 = def_cnt & 0xf;
1751 		match2 = tipc_own_addr(l->net) & 0xf;
1752 		if (match1 == match2)
1753 			return TIPC_LINK_SND_STATE;
1754 		return 0;
1755 	}
1756 
1757 	if (defq_len >= 3 && !((defq_len - 3) % 16)) {
1758 		u16 rcvgap = buf_seqno(skb_peek(dfq)) - l->rcv_nxt;
1759 
1760 		tipc_link_build_proto_msg(l, STATE_MSG, 0, 0,
1761 					  rcvgap, 0, 0, xmitq);
1762 	}
1763 	return 0;
1764 }
1765 
1766 /* tipc_link_rcv - process TIPC packets/messages arriving from off-node
1767  * @l: the link that should handle the message
1768  * @skb: TIPC packet
1769  * @xmitq: queue to place packets to be sent after this call
1770  */
1771 int tipc_link_rcv(struct tipc_link *l, struct sk_buff *skb,
1772 		  struct sk_buff_head *xmitq)
1773 {
1774 	struct sk_buff_head *defq = &l->deferdq;
1775 	struct tipc_msg *hdr = buf_msg(skb);
1776 	u16 seqno, rcv_nxt, win_lim;
1777 	int released = 0;
1778 	int rc = 0;
1779 
1780 	/* Verify and update link state */
1781 	if (unlikely(msg_user(hdr) == LINK_PROTOCOL))
1782 		return tipc_link_proto_rcv(l, skb, xmitq);
1783 
1784 	/* Don't send probe at next timeout expiration */
1785 	l->silent_intv_cnt = 0;
1786 
1787 	do {
1788 		hdr = buf_msg(skb);
1789 		seqno = msg_seqno(hdr);
1790 		rcv_nxt = l->rcv_nxt;
1791 		win_lim = rcv_nxt + TIPC_MAX_LINK_WIN;
1792 
1793 		if (unlikely(!link_is_up(l))) {
1794 			if (l->state == LINK_ESTABLISHING)
1795 				rc = TIPC_LINK_UP_EVT;
1796 			kfree_skb(skb);
1797 			break;
1798 		}
1799 
1800 		/* Drop if outside receive window */
1801 		if (unlikely(less(seqno, rcv_nxt) || more(seqno, win_lim))) {
1802 			l->stats.duplicates++;
1803 			kfree_skb(skb);
1804 			break;
1805 		}
1806 		released += tipc_link_advance_transmq(l, l, msg_ack(hdr), 0,
1807 						      NULL, NULL, NULL, NULL);
1808 
1809 		/* Defer delivery if sequence gap */
1810 		if (unlikely(seqno != rcv_nxt)) {
1811 			if (!__tipc_skb_queue_sorted(defq, seqno, skb))
1812 				l->stats.duplicates++;
1813 			rc |= tipc_link_build_nack_msg(l, xmitq);
1814 			break;
1815 		}
1816 
1817 		/* Deliver packet */
1818 		l->rcv_nxt++;
1819 		l->stats.recv_pkts++;
1820 
1821 		if (unlikely(msg_user(hdr) == TUNNEL_PROTOCOL))
1822 			rc |= tipc_link_tnl_rcv(l, skb, l->inputq);
1823 		else if (!tipc_data_input(l, skb, l->inputq))
1824 			rc |= tipc_link_input(l, skb, l->inputq, &l->reasm_buf);
1825 		if (unlikely(++l->rcv_unacked >= TIPC_MIN_LINK_WIN))
1826 			rc |= tipc_link_build_state_msg(l, xmitq);
1827 		if (unlikely(rc & ~TIPC_LINK_SND_STATE))
1828 			break;
1829 	} while ((skb = __tipc_skb_dequeue(defq, l->rcv_nxt)));
1830 
1831 	/* Forward queues and wake up waiting users */
1832 	if (released) {
1833 		tipc_link_update_cwin(l, released, 0);
1834 		tipc_link_advance_backlog(l, xmitq);
1835 		if (unlikely(!skb_queue_empty(&l->wakeupq)))
1836 			link_prepare_wakeup(l);
1837 	}
1838 	return rc;
1839 }
1840 
1841 static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
1842 				      bool probe_reply, u16 rcvgap,
1843 				      int tolerance, int priority,
1844 				      struct sk_buff_head *xmitq)
1845 {
1846 	struct tipc_mon_state *mstate = &l->mon_state;
1847 	struct sk_buff_head *dfq = &l->deferdq;
1848 	struct tipc_link *bcl = l->bc_rcvlink;
1849 	struct tipc_msg *hdr;
1850 	struct sk_buff *skb;
1851 	bool node_up = link_is_up(bcl);
1852 	u16 glen = 0, bc_rcvgap = 0;
1853 	int dlen = 0;
1854 	void *data;
1855 
1856 	/* Don't send protocol message during reset or link failover */
1857 	if (tipc_link_is_blocked(l))
1858 		return;
1859 
1860 	if (!tipc_link_is_up(l) && (mtyp == STATE_MSG))
1861 		return;
1862 
1863 	if ((probe || probe_reply) && !skb_queue_empty(dfq))
1864 		rcvgap = buf_seqno(skb_peek(dfq)) - l->rcv_nxt;
1865 
1866 	skb = tipc_msg_create(LINK_PROTOCOL, mtyp, INT_H_SIZE,
1867 			      tipc_max_domain_size + MAX_GAP_ACK_BLKS_SZ,
1868 			      l->addr, tipc_own_addr(l->net), 0, 0, 0);
1869 	if (!skb)
1870 		return;
1871 
1872 	hdr = buf_msg(skb);
1873 	data = msg_data(hdr);
1874 	msg_set_session(hdr, l->session);
1875 	msg_set_bearer_id(hdr, l->bearer_id);
1876 	msg_set_net_plane(hdr, l->net_plane);
1877 	msg_set_next_sent(hdr, l->snd_nxt);
1878 	msg_set_ack(hdr, l->rcv_nxt - 1);
1879 	msg_set_bcast_ack(hdr, bcl->rcv_nxt - 1);
1880 	msg_set_bc_ack_invalid(hdr, !node_up);
1881 	msg_set_last_bcast(hdr, l->bc_sndlink->snd_nxt - 1);
1882 	msg_set_link_tolerance(hdr, tolerance);
1883 	msg_set_linkprio(hdr, priority);
1884 	msg_set_redundant_link(hdr, node_up);
1885 	msg_set_seq_gap(hdr, 0);
1886 	msg_set_seqno(hdr, l->snd_nxt + U16_MAX / 2);
1887 
1888 	if (mtyp == STATE_MSG) {
1889 		if (l->peer_caps & TIPC_LINK_PROTO_SEQNO)
1890 			msg_set_seqno(hdr, l->snd_nxt_state++);
1891 		msg_set_seq_gap(hdr, rcvgap);
1892 		bc_rcvgap = link_bc_rcv_gap(bcl);
1893 		msg_set_bc_gap(hdr, bc_rcvgap);
1894 		msg_set_probe(hdr, probe);
1895 		msg_set_is_keepalive(hdr, probe || probe_reply);
1896 		if (l->peer_caps & TIPC_GAP_ACK_BLOCK)
1897 			glen = tipc_build_gap_ack_blks(l, hdr);
1898 		tipc_mon_prep(l->net, data + glen, &dlen, mstate, l->bearer_id);
1899 		msg_set_size(hdr, INT_H_SIZE + glen + dlen);
1900 		skb_trim(skb, INT_H_SIZE + glen + dlen);
1901 		l->stats.sent_states++;
1902 		l->rcv_unacked = 0;
1903 	} else {
1904 		/* RESET_MSG or ACTIVATE_MSG */
1905 		if (mtyp == ACTIVATE_MSG) {
1906 			msg_set_dest_session_valid(hdr, 1);
1907 			msg_set_dest_session(hdr, l->peer_session);
1908 		}
1909 		msg_set_max_pkt(hdr, l->advertised_mtu);
1910 		strcpy(data, l->if_name);
1911 		msg_set_size(hdr, INT_H_SIZE + TIPC_MAX_IF_NAME);
1912 		skb_trim(skb, INT_H_SIZE + TIPC_MAX_IF_NAME);
1913 	}
1914 	if (probe)
1915 		l->stats.sent_probes++;
1916 	if (rcvgap)
1917 		l->stats.sent_nacks++;
1918 	if (bc_rcvgap)
1919 		bcl->stats.sent_nacks++;
1920 	skb->priority = TC_PRIO_CONTROL;
1921 	__skb_queue_tail(xmitq, skb);
1922 	trace_tipc_proto_build(skb, false, l->name);
1923 }
1924 
1925 void tipc_link_create_dummy_tnl_msg(struct tipc_link *l,
1926 				    struct sk_buff_head *xmitq)
1927 {
1928 	u32 onode = tipc_own_addr(l->net);
1929 	struct tipc_msg *hdr, *ihdr;
1930 	struct sk_buff_head tnlq;
1931 	struct sk_buff *skb;
1932 	u32 dnode = l->addr;
1933 
1934 	__skb_queue_head_init(&tnlq);
1935 	skb = tipc_msg_create(TUNNEL_PROTOCOL, FAILOVER_MSG,
1936 			      INT_H_SIZE, BASIC_H_SIZE,
1937 			      dnode, onode, 0, 0, 0);
1938 	if (!skb) {
1939 		pr_warn("%sunable to create tunnel packet\n", link_co_err);
1940 		return;
1941 	}
1942 
1943 	hdr = buf_msg(skb);
1944 	msg_set_msgcnt(hdr, 1);
1945 	msg_set_bearer_id(hdr, l->peer_bearer_id);
1946 
1947 	ihdr = (struct tipc_msg *)msg_data(hdr);
1948 	tipc_msg_init(onode, ihdr, TIPC_LOW_IMPORTANCE, TIPC_DIRECT_MSG,
1949 		      BASIC_H_SIZE, dnode);
1950 	msg_set_errcode(ihdr, TIPC_ERR_NO_PORT);
1951 	__skb_queue_tail(&tnlq, skb);
1952 	tipc_link_xmit(l, &tnlq, xmitq);
1953 }
1954 
1955 /* tipc_link_tnl_prepare(): prepare and return a list of tunnel packets
1956  * with contents of the link's transmit and backlog queues.
1957  */
1958 void tipc_link_tnl_prepare(struct tipc_link *l, struct tipc_link *tnl,
1959 			   int mtyp, struct sk_buff_head *xmitq)
1960 {
1961 	struct sk_buff_head *fdefq = &tnl->failover_deferdq;
1962 	struct sk_buff *skb, *tnlskb;
1963 	struct tipc_msg *hdr, tnlhdr;
1964 	struct sk_buff_head *queue = &l->transmq;
1965 	struct sk_buff_head tmpxq, tnlq, frags;
1966 	u16 pktlen, pktcnt, seqno = l->snd_nxt;
1967 	bool pktcnt_need_update = false;
1968 	u16 syncpt;
1969 	int rc;
1970 
1971 	if (!tnl)
1972 		return;
1973 
1974 	__skb_queue_head_init(&tnlq);
1975 	/* Link Synching:
1976 	 * From now on, send only one single ("dummy") SYNCH message
1977 	 * to peer. The SYNCH message does not contain any data, just
1978 	 * a header conveying the synch point to the peer.
1979 	 */
1980 	if (mtyp == SYNCH_MSG && (tnl->peer_caps & TIPC_TUNNEL_ENHANCED)) {
1981 		tnlskb = tipc_msg_create(TUNNEL_PROTOCOL, SYNCH_MSG,
1982 					 INT_H_SIZE, 0, l->addr,
1983 					 tipc_own_addr(l->net),
1984 					 0, 0, 0);
1985 		if (!tnlskb) {
1986 			pr_warn("%sunable to create dummy SYNCH_MSG\n",
1987 				link_co_err);
1988 			return;
1989 		}
1990 
1991 		hdr = buf_msg(tnlskb);
1992 		syncpt = l->snd_nxt + skb_queue_len(&l->backlogq) - 1;
1993 		msg_set_syncpt(hdr, syncpt);
1994 		msg_set_bearer_id(hdr, l->peer_bearer_id);
1995 		__skb_queue_tail(&tnlq, tnlskb);
1996 		tipc_link_xmit(tnl, &tnlq, xmitq);
1997 		return;
1998 	}
1999 
2000 	__skb_queue_head_init(&tmpxq);
2001 	__skb_queue_head_init(&frags);
2002 	/* At least one packet required for safe algorithm => add dummy */
2003 	skb = tipc_msg_create(TIPC_LOW_IMPORTANCE, TIPC_DIRECT_MSG,
2004 			      BASIC_H_SIZE, 0, l->addr, tipc_own_addr(l->net),
2005 			      0, 0, TIPC_ERR_NO_PORT);
2006 	if (!skb) {
2007 		pr_warn("%sunable to create tunnel packet\n", link_co_err);
2008 		return;
2009 	}
2010 	__skb_queue_tail(&tnlq, skb);
2011 	tipc_link_xmit(l, &tnlq, &tmpxq);
2012 	__skb_queue_purge(&tmpxq);
2013 
2014 	/* Initialize reusable tunnel packet header */
2015 	tipc_msg_init(tipc_own_addr(l->net), &tnlhdr, TUNNEL_PROTOCOL,
2016 		      mtyp, INT_H_SIZE, l->addr);
2017 	if (mtyp == SYNCH_MSG)
2018 		pktcnt = l->snd_nxt - buf_seqno(skb_peek(&l->transmq));
2019 	else
2020 		pktcnt = skb_queue_len(&l->transmq);
2021 	pktcnt += skb_queue_len(&l->backlogq);
2022 	msg_set_msgcnt(&tnlhdr, pktcnt);
2023 	msg_set_bearer_id(&tnlhdr, l->peer_bearer_id);
2024 tnl:
2025 	/* Wrap each packet into a tunnel packet */
2026 	skb_queue_walk(queue, skb) {
2027 		hdr = buf_msg(skb);
2028 		if (queue == &l->backlogq)
2029 			msg_set_seqno(hdr, seqno++);
2030 		pktlen = msg_size(hdr);
2031 
2032 		/* Tunnel link MTU is not large enough? This could be
2033 		 * due to:
2034 		 * 1) Link MTU has just changed or set differently;
2035 		 * 2) Or FAILOVER on the top of a SYNCH message
2036 		 *
2037 		 * The 2nd case should not happen if peer supports
2038 		 * TIPC_TUNNEL_ENHANCED
2039 		 */
2040 		if (pktlen > tnl->mtu - INT_H_SIZE) {
2041 			if (mtyp == FAILOVER_MSG &&
2042 			    (tnl->peer_caps & TIPC_TUNNEL_ENHANCED)) {
2043 				rc = tipc_msg_fragment(skb, &tnlhdr, tnl->mtu,
2044 						       &frags);
2045 				if (rc) {
2046 					pr_warn("%sunable to frag msg: rc %d\n",
2047 						link_co_err, rc);
2048 					return;
2049 				}
2050 				pktcnt += skb_queue_len(&frags) - 1;
2051 				pktcnt_need_update = true;
2052 				skb_queue_splice_tail_init(&frags, &tnlq);
2053 				continue;
2054 			}
2055 			/* Unluckily, peer doesn't have TIPC_TUNNEL_ENHANCED
2056 			 * => Just warn it and return!
2057 			 */
2058 			pr_warn_ratelimited("%stoo large msg <%d, %d>: %d!\n",
2059 					    link_co_err, msg_user(hdr),
2060 					    msg_type(hdr), msg_size(hdr));
2061 			return;
2062 		}
2063 
2064 		msg_set_size(&tnlhdr, pktlen + INT_H_SIZE);
2065 		tnlskb = tipc_buf_acquire(pktlen + INT_H_SIZE, GFP_ATOMIC);
2066 		if (!tnlskb) {
2067 			pr_warn("%sunable to send packet\n", link_co_err);
2068 			return;
2069 		}
2070 		skb_copy_to_linear_data(tnlskb, &tnlhdr, INT_H_SIZE);
2071 		skb_copy_to_linear_data_offset(tnlskb, INT_H_SIZE, hdr, pktlen);
2072 		__skb_queue_tail(&tnlq, tnlskb);
2073 	}
2074 	if (queue != &l->backlogq) {
2075 		queue = &l->backlogq;
2076 		goto tnl;
2077 	}
2078 
2079 	if (pktcnt_need_update)
2080 		skb_queue_walk(&tnlq, skb) {
2081 			hdr = buf_msg(skb);
2082 			msg_set_msgcnt(hdr, pktcnt);
2083 		}
2084 
2085 	tipc_link_xmit(tnl, &tnlq, xmitq);
2086 
2087 	if (mtyp == FAILOVER_MSG) {
2088 		tnl->drop_point = l->rcv_nxt;
2089 		tnl->failover_reasm_skb = l->reasm_buf;
2090 		l->reasm_buf = NULL;
2091 
2092 		/* Failover the link's deferdq */
2093 		if (unlikely(!skb_queue_empty(fdefq))) {
2094 			pr_warn("Link failover deferdq not empty: %d!\n",
2095 				skb_queue_len(fdefq));
2096 			__skb_queue_purge(fdefq);
2097 		}
2098 		skb_queue_splice_init(&l->deferdq, fdefq);
2099 	}
2100 }
2101 
2102 /**
2103  * tipc_link_failover_prepare() - prepare tnl for link failover
2104  *
2105  * This is a special version of the precursor - tipc_link_tnl_prepare(),
2106  * see the tipc_node_link_failover() for details
2107  *
2108  * @l: failover link
2109  * @tnl: tunnel link
2110  * @xmitq: queue for messages to be xmited
2111  */
2112 void tipc_link_failover_prepare(struct tipc_link *l, struct tipc_link *tnl,
2113 				struct sk_buff_head *xmitq)
2114 {
2115 	struct sk_buff_head *fdefq = &tnl->failover_deferdq;
2116 
2117 	tipc_link_create_dummy_tnl_msg(tnl, xmitq);
2118 
2119 	/* This failover link endpoint was never established before,
2120 	 * so it has not received anything from peer.
2121 	 * Otherwise, it must be a normal failover situation or the
2122 	 * node has entered SELF_DOWN_PEER_LEAVING and both peer nodes
2123 	 * would have to start over from scratch instead.
2124 	 */
2125 	tnl->drop_point = 1;
2126 	tnl->failover_reasm_skb = NULL;
2127 
2128 	/* Initiate the link's failover deferdq */
2129 	if (unlikely(!skb_queue_empty(fdefq))) {
2130 		pr_warn("Link failover deferdq not empty: %d!\n",
2131 			skb_queue_len(fdefq));
2132 		__skb_queue_purge(fdefq);
2133 	}
2134 }
2135 
2136 /* tipc_link_validate_msg(): validate message against current link state
2137  * Returns true if message should be accepted, otherwise false
2138  */
2139 bool tipc_link_validate_msg(struct tipc_link *l, struct tipc_msg *hdr)
2140 {
2141 	u16 curr_session = l->peer_session;
2142 	u16 session = msg_session(hdr);
2143 	int mtyp = msg_type(hdr);
2144 
2145 	if (msg_user(hdr) != LINK_PROTOCOL)
2146 		return true;
2147 
2148 	switch (mtyp) {
2149 	case RESET_MSG:
2150 		if (!l->in_session)
2151 			return true;
2152 		/* Accept only RESET with new session number */
2153 		return more(session, curr_session);
2154 	case ACTIVATE_MSG:
2155 		if (!l->in_session)
2156 			return true;
2157 		/* Accept only ACTIVATE with new or current session number */
2158 		return !less(session, curr_session);
2159 	case STATE_MSG:
2160 		/* Accept only STATE with current session number */
2161 		if (!l->in_session)
2162 			return false;
2163 		if (session != curr_session)
2164 			return false;
2165 		/* Extra sanity check */
2166 		if (!link_is_up(l) && msg_ack(hdr))
2167 			return false;
2168 		if (!(l->peer_caps & TIPC_LINK_PROTO_SEQNO))
2169 			return true;
2170 		/* Accept only STATE with new sequence number */
2171 		return !less(msg_seqno(hdr), l->rcv_nxt_state);
2172 	default:
2173 		return false;
2174 	}
2175 }
2176 
2177 /* tipc_link_proto_rcv(): receive link level protocol message :
2178  * Note that network plane id propagates through the network, and may
2179  * change at any time. The node with lowest numerical id determines
2180  * network plane
2181  */
2182 static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
2183 			       struct sk_buff_head *xmitq)
2184 {
2185 	struct tipc_msg *hdr = buf_msg(skb);
2186 	struct tipc_gap_ack_blks *ga = NULL;
2187 	bool reply = msg_probe(hdr), retransmitted = false;
2188 	u16 dlen = msg_data_sz(hdr), glen = 0;
2189 	u16 peers_snd_nxt =  msg_next_sent(hdr);
2190 	u16 peers_tol = msg_link_tolerance(hdr);
2191 	u16 peers_prio = msg_linkprio(hdr);
2192 	u16 gap = msg_seq_gap(hdr);
2193 	u16 ack = msg_ack(hdr);
2194 	u16 rcv_nxt = l->rcv_nxt;
2195 	u16 rcvgap = 0;
2196 	int mtyp = msg_type(hdr);
2197 	int rc = 0, released;
2198 	char *if_name;
2199 	void *data;
2200 
2201 	trace_tipc_proto_rcv(skb, false, l->name);
2202 	if (tipc_link_is_blocked(l) || !xmitq)
2203 		goto exit;
2204 
2205 	if (tipc_own_addr(l->net) > msg_prevnode(hdr))
2206 		l->net_plane = msg_net_plane(hdr);
2207 
2208 	skb_linearize(skb);
2209 	hdr = buf_msg(skb);
2210 	data = msg_data(hdr);
2211 
2212 	if (!tipc_link_validate_msg(l, hdr)) {
2213 		trace_tipc_skb_dump(skb, false, "PROTO invalid (1)!");
2214 		trace_tipc_link_dump(l, TIPC_DUMP_NONE, "PROTO invalid (1)!");
2215 		goto exit;
2216 	}
2217 
2218 	switch (mtyp) {
2219 	case RESET_MSG:
2220 	case ACTIVATE_MSG:
2221 		/* Complete own link name with peer's interface name */
2222 		if_name =  strrchr(l->name, ':') + 1;
2223 		if (sizeof(l->name) - (if_name - l->name) <= TIPC_MAX_IF_NAME)
2224 			break;
2225 		if (msg_data_sz(hdr) < TIPC_MAX_IF_NAME)
2226 			break;
2227 		strncpy(if_name, data, TIPC_MAX_IF_NAME);
2228 
2229 		/* Update own tolerance if peer indicates a non-zero value */
2230 		if (in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL)) {
2231 			l->tolerance = peers_tol;
2232 			l->bc_rcvlink->tolerance = peers_tol;
2233 		}
2234 		/* Update own priority if peer's priority is higher */
2235 		if (in_range(peers_prio, l->priority + 1, TIPC_MAX_LINK_PRI))
2236 			l->priority = peers_prio;
2237 
2238 		/* If peer is going down we want full re-establish cycle */
2239 		if (msg_peer_stopping(hdr)) {
2240 			rc = tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
2241 			break;
2242 		}
2243 
2244 		/* If this endpoint was re-created while peer was ESTABLISHING
2245 		 * it doesn't know current session number. Force re-synch.
2246 		 */
2247 		if (mtyp == ACTIVATE_MSG && msg_dest_session_valid(hdr) &&
2248 		    l->session != msg_dest_session(hdr)) {
2249 			if (less(l->session, msg_dest_session(hdr)))
2250 				l->session = msg_dest_session(hdr) + 1;
2251 			break;
2252 		}
2253 
2254 		/* ACTIVATE_MSG serves as PEER_RESET if link is already down */
2255 		if (mtyp == RESET_MSG || !link_is_up(l))
2256 			rc = tipc_link_fsm_evt(l, LINK_PEER_RESET_EVT);
2257 
2258 		/* ACTIVATE_MSG takes up link if it was already locally reset */
2259 		if (mtyp == ACTIVATE_MSG && l->state == LINK_ESTABLISHING)
2260 			rc = TIPC_LINK_UP_EVT;
2261 
2262 		l->peer_session = msg_session(hdr);
2263 		l->in_session = true;
2264 		l->peer_bearer_id = msg_bearer_id(hdr);
2265 		if (l->mtu > msg_max_pkt(hdr))
2266 			l->mtu = msg_max_pkt(hdr);
2267 		break;
2268 
2269 	case STATE_MSG:
2270 		l->rcv_nxt_state = msg_seqno(hdr) + 1;
2271 
2272 		/* Update own tolerance if peer indicates a non-zero value */
2273 		if (in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL)) {
2274 			l->tolerance = peers_tol;
2275 			l->bc_rcvlink->tolerance = peers_tol;
2276 		}
2277 		/* Update own prio if peer indicates a different value */
2278 		if ((peers_prio != l->priority) &&
2279 		    in_range(peers_prio, 1, TIPC_MAX_LINK_PRI)) {
2280 			l->priority = peers_prio;
2281 			rc = tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
2282 		}
2283 
2284 		l->silent_intv_cnt = 0;
2285 		l->stats.recv_states++;
2286 		if (msg_probe(hdr))
2287 			l->stats.recv_probes++;
2288 
2289 		if (!link_is_up(l)) {
2290 			if (l->state == LINK_ESTABLISHING)
2291 				rc = TIPC_LINK_UP_EVT;
2292 			break;
2293 		}
2294 
2295 		/* Receive Gap ACK blocks from peer if any */
2296 		glen = tipc_get_gap_ack_blks(&ga, l, hdr, true);
2297 
2298 		tipc_mon_rcv(l->net, data + glen, dlen - glen, l->addr,
2299 			     &l->mon_state, l->bearer_id);
2300 
2301 		/* Send NACK if peer has sent pkts we haven't received yet */
2302 		if ((reply || msg_is_keepalive(hdr)) &&
2303 		    more(peers_snd_nxt, rcv_nxt) &&
2304 		    !tipc_link_is_synching(l) &&
2305 		    skb_queue_empty(&l->deferdq))
2306 			rcvgap = peers_snd_nxt - l->rcv_nxt;
2307 		if (rcvgap || reply)
2308 			tipc_link_build_proto_msg(l, STATE_MSG, 0, reply,
2309 						  rcvgap, 0, 0, xmitq);
2310 
2311 		released = tipc_link_advance_transmq(l, l, ack, gap, ga, xmitq,
2312 						     &retransmitted, &rc);
2313 		if (gap)
2314 			l->stats.recv_nacks++;
2315 		if (released || retransmitted)
2316 			tipc_link_update_cwin(l, released, retransmitted);
2317 		if (released)
2318 			tipc_link_advance_backlog(l, xmitq);
2319 		if (unlikely(!skb_queue_empty(&l->wakeupq)))
2320 			link_prepare_wakeup(l);
2321 	}
2322 exit:
2323 	kfree_skb(skb);
2324 	return rc;
2325 }
2326 
2327 /* tipc_link_build_bc_proto_msg() - create broadcast protocol message
2328  */
2329 static bool tipc_link_build_bc_proto_msg(struct tipc_link *l, bool bcast,
2330 					 u16 peers_snd_nxt,
2331 					 struct sk_buff_head *xmitq)
2332 {
2333 	struct sk_buff *skb;
2334 	struct tipc_msg *hdr;
2335 	struct sk_buff *dfrd_skb = skb_peek(&l->deferdq);
2336 	u16 ack = l->rcv_nxt - 1;
2337 	u16 gap_to = peers_snd_nxt - 1;
2338 
2339 	skb = tipc_msg_create(BCAST_PROTOCOL, STATE_MSG, INT_H_SIZE,
2340 			      0, l->addr, tipc_own_addr(l->net), 0, 0, 0);
2341 	if (!skb)
2342 		return false;
2343 	hdr = buf_msg(skb);
2344 	msg_set_last_bcast(hdr, l->bc_sndlink->snd_nxt - 1);
2345 	msg_set_bcast_ack(hdr, ack);
2346 	msg_set_bcgap_after(hdr, ack);
2347 	if (dfrd_skb)
2348 		gap_to = buf_seqno(dfrd_skb) - 1;
2349 	msg_set_bcgap_to(hdr, gap_to);
2350 	msg_set_non_seq(hdr, bcast);
2351 	__skb_queue_tail(xmitq, skb);
2352 	return true;
2353 }
2354 
2355 /* tipc_link_build_bc_init_msg() - synchronize broadcast link endpoints.
2356  *
2357  * Give a newly added peer node the sequence number where it should
2358  * start receiving and acking broadcast packets.
2359  */
2360 static void tipc_link_build_bc_init_msg(struct tipc_link *l,
2361 					struct sk_buff_head *xmitq)
2362 {
2363 	struct sk_buff_head list;
2364 
2365 	__skb_queue_head_init(&list);
2366 	if (!tipc_link_build_bc_proto_msg(l->bc_rcvlink, false, 0, &list))
2367 		return;
2368 	msg_set_bc_ack_invalid(buf_msg(skb_peek(&list)), true);
2369 	tipc_link_xmit(l, &list, xmitq);
2370 }
2371 
2372 /* tipc_link_bc_init_rcv - receive initial broadcast synch data from peer
2373  */
2374 void tipc_link_bc_init_rcv(struct tipc_link *l, struct tipc_msg *hdr)
2375 {
2376 	int mtyp = msg_type(hdr);
2377 	u16 peers_snd_nxt = msg_bc_snd_nxt(hdr);
2378 
2379 	if (link_is_up(l))
2380 		return;
2381 
2382 	if (msg_user(hdr) == BCAST_PROTOCOL) {
2383 		l->rcv_nxt = peers_snd_nxt;
2384 		l->state = LINK_ESTABLISHED;
2385 		return;
2386 	}
2387 
2388 	if (l->peer_caps & TIPC_BCAST_SYNCH)
2389 		return;
2390 
2391 	if (msg_peer_node_is_up(hdr))
2392 		return;
2393 
2394 	/* Compatibility: accept older, less safe initial synch data */
2395 	if ((mtyp == RESET_MSG) || (mtyp == ACTIVATE_MSG))
2396 		l->rcv_nxt = peers_snd_nxt;
2397 }
2398 
2399 /* tipc_link_bc_sync_rcv - update rcv link according to peer's send state
2400  */
2401 int tipc_link_bc_sync_rcv(struct tipc_link *l, struct tipc_msg *hdr,
2402 			  struct sk_buff_head *xmitq)
2403 {
2404 	u16 peers_snd_nxt = msg_bc_snd_nxt(hdr);
2405 	int rc = 0;
2406 
2407 	if (!link_is_up(l))
2408 		return rc;
2409 
2410 	if (!msg_peer_node_is_up(hdr))
2411 		return rc;
2412 
2413 	/* Open when peer acknowledges our bcast init msg (pkt #1) */
2414 	if (msg_ack(hdr))
2415 		l->bc_peer_is_up = true;
2416 
2417 	if (!l->bc_peer_is_up)
2418 		return rc;
2419 
2420 	/* Ignore if peers_snd_nxt goes beyond receive window */
2421 	if (more(peers_snd_nxt, l->rcv_nxt + l->window))
2422 		return rc;
2423 
2424 	l->snd_nxt = peers_snd_nxt;
2425 	if (link_bc_rcv_gap(l))
2426 		rc |= TIPC_LINK_SND_STATE;
2427 
2428 	/* Return now if sender supports nack via STATE messages */
2429 	if (l->peer_caps & TIPC_BCAST_STATE_NACK)
2430 		return rc;
2431 
2432 	/* Otherwise, be backwards compatible */
2433 
2434 	if (!more(peers_snd_nxt, l->rcv_nxt)) {
2435 		l->nack_state = BC_NACK_SND_CONDITIONAL;
2436 		return 0;
2437 	}
2438 
2439 	/* Don't NACK if one was recently sent or peeked */
2440 	if (l->nack_state == BC_NACK_SND_SUPPRESS) {
2441 		l->nack_state = BC_NACK_SND_UNCONDITIONAL;
2442 		return 0;
2443 	}
2444 
2445 	/* Conditionally delay NACK sending until next synch rcv */
2446 	if (l->nack_state == BC_NACK_SND_CONDITIONAL) {
2447 		l->nack_state = BC_NACK_SND_UNCONDITIONAL;
2448 		if ((peers_snd_nxt - l->rcv_nxt) < TIPC_MIN_LINK_WIN)
2449 			return 0;
2450 	}
2451 
2452 	/* Send NACK now but suppress next one */
2453 	tipc_link_build_bc_proto_msg(l, true, peers_snd_nxt, xmitq);
2454 	l->nack_state = BC_NACK_SND_SUPPRESS;
2455 	return 0;
2456 }
2457 
2458 int tipc_link_bc_ack_rcv(struct tipc_link *r, u16 acked, u16 gap,
2459 			 struct tipc_gap_ack_blks *ga,
2460 			 struct sk_buff_head *xmitq,
2461 			 struct sk_buff_head *retrq)
2462 {
2463 	struct tipc_link *l = r->bc_sndlink;
2464 	bool unused = false;
2465 	int rc = 0;
2466 
2467 	if (!link_is_up(r) || !r->bc_peer_is_up)
2468 		return 0;
2469 
2470 	if (gap) {
2471 		l->stats.recv_nacks++;
2472 		r->stats.recv_nacks++;
2473 	}
2474 
2475 	if (less(acked, r->acked) || (acked == r->acked && !gap && !ga))
2476 		return 0;
2477 
2478 	trace_tipc_link_bc_ack(r, acked, gap, &l->transmq);
2479 	tipc_link_advance_transmq(l, r, acked, gap, ga, retrq, &unused, &rc);
2480 
2481 	tipc_link_advance_backlog(l, xmitq);
2482 	if (unlikely(!skb_queue_empty(&l->wakeupq)))
2483 		link_prepare_wakeup(l);
2484 
2485 	return rc;
2486 }
2487 
2488 /* tipc_link_bc_nack_rcv(): receive broadcast nack message
2489  * This function is here for backwards compatibility, since
2490  * no BCAST_PROTOCOL/STATE messages occur from TIPC v2.5.
2491  */
2492 int tipc_link_bc_nack_rcv(struct tipc_link *l, struct sk_buff *skb,
2493 			  struct sk_buff_head *xmitq)
2494 {
2495 	struct tipc_msg *hdr = buf_msg(skb);
2496 	u32 dnode = msg_destnode(hdr);
2497 	int mtyp = msg_type(hdr);
2498 	u16 acked = msg_bcast_ack(hdr);
2499 	u16 from = acked + 1;
2500 	u16 to = msg_bcgap_to(hdr);
2501 	u16 peers_snd_nxt = to + 1;
2502 	int rc = 0;
2503 
2504 	kfree_skb(skb);
2505 
2506 	if (!tipc_link_is_up(l) || !l->bc_peer_is_up)
2507 		return 0;
2508 
2509 	if (mtyp != STATE_MSG)
2510 		return 0;
2511 
2512 	if (dnode == tipc_own_addr(l->net)) {
2513 		rc = tipc_link_bc_ack_rcv(l, acked, to - acked, NULL, xmitq,
2514 					  xmitq);
2515 		l->stats.recv_nacks++;
2516 		return rc;
2517 	}
2518 
2519 	/* Msg for other node => suppress own NACK at next sync if applicable */
2520 	if (more(peers_snd_nxt, l->rcv_nxt) && !less(l->rcv_nxt, from))
2521 		l->nack_state = BC_NACK_SND_SUPPRESS;
2522 
2523 	return 0;
2524 }
2525 
2526 void tipc_link_set_queue_limits(struct tipc_link *l, u32 min_win, u32 max_win)
2527 {
2528 	int max_bulk = TIPC_MAX_PUBL / (l->mtu / ITEM_SIZE);
2529 
2530 	l->min_win = min_win;
2531 	l->ssthresh = max_win;
2532 	l->max_win = max_win;
2533 	l->window = min_win;
2534 	l->backlog[TIPC_LOW_IMPORTANCE].limit      = min_win * 2;
2535 	l->backlog[TIPC_MEDIUM_IMPORTANCE].limit   = min_win * 4;
2536 	l->backlog[TIPC_HIGH_IMPORTANCE].limit     = min_win * 6;
2537 	l->backlog[TIPC_CRITICAL_IMPORTANCE].limit = min_win * 8;
2538 	l->backlog[TIPC_SYSTEM_IMPORTANCE].limit   = max_bulk;
2539 }
2540 
2541 /**
2542  * link_reset_stats - reset link statistics
2543  * @l: pointer to link
2544  */
2545 void tipc_link_reset_stats(struct tipc_link *l)
2546 {
2547 	memset(&l->stats, 0, sizeof(l->stats));
2548 }
2549 
2550 static void link_print(struct tipc_link *l, const char *str)
2551 {
2552 	struct sk_buff *hskb = skb_peek(&l->transmq);
2553 	u16 head = hskb ? msg_seqno(buf_msg(hskb)) : l->snd_nxt - 1;
2554 	u16 tail = l->snd_nxt - 1;
2555 
2556 	pr_info("%s Link <%s> state %x\n", str, l->name, l->state);
2557 	pr_info("XMTQ: %u [%u-%u], BKLGQ: %u, SNDNX: %u, RCVNX: %u\n",
2558 		skb_queue_len(&l->transmq), head, tail,
2559 		skb_queue_len(&l->backlogq), l->snd_nxt, l->rcv_nxt);
2560 }
2561 
2562 /* Parse and validate nested (link) properties valid for media, bearer and link
2563  */
2564 int tipc_nl_parse_link_prop(struct nlattr *prop, struct nlattr *props[])
2565 {
2566 	int err;
2567 
2568 	err = nla_parse_nested_deprecated(props, TIPC_NLA_PROP_MAX, prop,
2569 					  tipc_nl_prop_policy, NULL);
2570 	if (err)
2571 		return err;
2572 
2573 	if (props[TIPC_NLA_PROP_PRIO]) {
2574 		u32 prio;
2575 
2576 		prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
2577 		if (prio > TIPC_MAX_LINK_PRI)
2578 			return -EINVAL;
2579 	}
2580 
2581 	if (props[TIPC_NLA_PROP_TOL]) {
2582 		u32 tol;
2583 
2584 		tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
2585 		if ((tol < TIPC_MIN_LINK_TOL) || (tol > TIPC_MAX_LINK_TOL))
2586 			return -EINVAL;
2587 	}
2588 
2589 	if (props[TIPC_NLA_PROP_WIN]) {
2590 		u32 max_win;
2591 
2592 		max_win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
2593 		if (max_win < TIPC_DEF_LINK_WIN || max_win > TIPC_MAX_LINK_WIN)
2594 			return -EINVAL;
2595 	}
2596 
2597 	return 0;
2598 }
2599 
2600 static int __tipc_nl_add_stats(struct sk_buff *skb, struct tipc_stats *s)
2601 {
2602 	int i;
2603 	struct nlattr *stats;
2604 
2605 	struct nla_map {
2606 		u32 key;
2607 		u32 val;
2608 	};
2609 
2610 	struct nla_map map[] = {
2611 		{TIPC_NLA_STATS_RX_INFO, 0},
2612 		{TIPC_NLA_STATS_RX_FRAGMENTS, s->recv_fragments},
2613 		{TIPC_NLA_STATS_RX_FRAGMENTED, s->recv_fragmented},
2614 		{TIPC_NLA_STATS_RX_BUNDLES, s->recv_bundles},
2615 		{TIPC_NLA_STATS_RX_BUNDLED, s->recv_bundled},
2616 		{TIPC_NLA_STATS_TX_INFO, 0},
2617 		{TIPC_NLA_STATS_TX_FRAGMENTS, s->sent_fragments},
2618 		{TIPC_NLA_STATS_TX_FRAGMENTED, s->sent_fragmented},
2619 		{TIPC_NLA_STATS_TX_BUNDLES, s->sent_bundles},
2620 		{TIPC_NLA_STATS_TX_BUNDLED, s->sent_bundled},
2621 		{TIPC_NLA_STATS_MSG_PROF_TOT, (s->msg_length_counts) ?
2622 			s->msg_length_counts : 1},
2623 		{TIPC_NLA_STATS_MSG_LEN_CNT, s->msg_length_counts},
2624 		{TIPC_NLA_STATS_MSG_LEN_TOT, s->msg_lengths_total},
2625 		{TIPC_NLA_STATS_MSG_LEN_P0, s->msg_length_profile[0]},
2626 		{TIPC_NLA_STATS_MSG_LEN_P1, s->msg_length_profile[1]},
2627 		{TIPC_NLA_STATS_MSG_LEN_P2, s->msg_length_profile[2]},
2628 		{TIPC_NLA_STATS_MSG_LEN_P3, s->msg_length_profile[3]},
2629 		{TIPC_NLA_STATS_MSG_LEN_P4, s->msg_length_profile[4]},
2630 		{TIPC_NLA_STATS_MSG_LEN_P5, s->msg_length_profile[5]},
2631 		{TIPC_NLA_STATS_MSG_LEN_P6, s->msg_length_profile[6]},
2632 		{TIPC_NLA_STATS_RX_STATES, s->recv_states},
2633 		{TIPC_NLA_STATS_RX_PROBES, s->recv_probes},
2634 		{TIPC_NLA_STATS_RX_NACKS, s->recv_nacks},
2635 		{TIPC_NLA_STATS_RX_DEFERRED, s->deferred_recv},
2636 		{TIPC_NLA_STATS_TX_STATES, s->sent_states},
2637 		{TIPC_NLA_STATS_TX_PROBES, s->sent_probes},
2638 		{TIPC_NLA_STATS_TX_NACKS, s->sent_nacks},
2639 		{TIPC_NLA_STATS_TX_ACKS, s->sent_acks},
2640 		{TIPC_NLA_STATS_RETRANSMITTED, s->retransmitted},
2641 		{TIPC_NLA_STATS_DUPLICATES, s->duplicates},
2642 		{TIPC_NLA_STATS_LINK_CONGS, s->link_congs},
2643 		{TIPC_NLA_STATS_MAX_QUEUE, s->max_queue_sz},
2644 		{TIPC_NLA_STATS_AVG_QUEUE, s->queue_sz_counts ?
2645 			(s->accu_queue_sz / s->queue_sz_counts) : 0}
2646 	};
2647 
2648 	stats = nla_nest_start_noflag(skb, TIPC_NLA_LINK_STATS);
2649 	if (!stats)
2650 		return -EMSGSIZE;
2651 
2652 	for (i = 0; i <  ARRAY_SIZE(map); i++)
2653 		if (nla_put_u32(skb, map[i].key, map[i].val))
2654 			goto msg_full;
2655 
2656 	nla_nest_end(skb, stats);
2657 
2658 	return 0;
2659 msg_full:
2660 	nla_nest_cancel(skb, stats);
2661 
2662 	return -EMSGSIZE;
2663 }
2664 
2665 /* Caller should hold appropriate locks to protect the link */
2666 int __tipc_nl_add_link(struct net *net, struct tipc_nl_msg *msg,
2667 		       struct tipc_link *link, int nlflags)
2668 {
2669 	u32 self = tipc_own_addr(net);
2670 	struct nlattr *attrs;
2671 	struct nlattr *prop;
2672 	void *hdr;
2673 	int err;
2674 
2675 	hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
2676 			  nlflags, TIPC_NL_LINK_GET);
2677 	if (!hdr)
2678 		return -EMSGSIZE;
2679 
2680 	attrs = nla_nest_start_noflag(msg->skb, TIPC_NLA_LINK);
2681 	if (!attrs)
2682 		goto msg_full;
2683 
2684 	if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, link->name))
2685 		goto attr_msg_full;
2686 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_DEST, tipc_cluster_mask(self)))
2687 		goto attr_msg_full;
2688 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_MTU, link->mtu))
2689 		goto attr_msg_full;
2690 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, link->stats.recv_pkts))
2691 		goto attr_msg_full;
2692 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, link->stats.sent_pkts))
2693 		goto attr_msg_full;
2694 
2695 	if (tipc_link_is_up(link))
2696 		if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
2697 			goto attr_msg_full;
2698 	if (link->active)
2699 		if (nla_put_flag(msg->skb, TIPC_NLA_LINK_ACTIVE))
2700 			goto attr_msg_full;
2701 
2702 	prop = nla_nest_start_noflag(msg->skb, TIPC_NLA_LINK_PROP);
2703 	if (!prop)
2704 		goto attr_msg_full;
2705 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
2706 		goto prop_msg_full;
2707 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_TOL, link->tolerance))
2708 		goto prop_msg_full;
2709 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN,
2710 			link->window))
2711 		goto prop_msg_full;
2712 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
2713 		goto prop_msg_full;
2714 	nla_nest_end(msg->skb, prop);
2715 
2716 	err = __tipc_nl_add_stats(msg->skb, &link->stats);
2717 	if (err)
2718 		goto attr_msg_full;
2719 
2720 	nla_nest_end(msg->skb, attrs);
2721 	genlmsg_end(msg->skb, hdr);
2722 
2723 	return 0;
2724 
2725 prop_msg_full:
2726 	nla_nest_cancel(msg->skb, prop);
2727 attr_msg_full:
2728 	nla_nest_cancel(msg->skb, attrs);
2729 msg_full:
2730 	genlmsg_cancel(msg->skb, hdr);
2731 
2732 	return -EMSGSIZE;
2733 }
2734 
2735 static int __tipc_nl_add_bc_link_stat(struct sk_buff *skb,
2736 				      struct tipc_stats *stats)
2737 {
2738 	int i;
2739 	struct nlattr *nest;
2740 
2741 	struct nla_map {
2742 		__u32 key;
2743 		__u32 val;
2744 	};
2745 
2746 	struct nla_map map[] = {
2747 		{TIPC_NLA_STATS_RX_INFO, stats->recv_pkts},
2748 		{TIPC_NLA_STATS_RX_FRAGMENTS, stats->recv_fragments},
2749 		{TIPC_NLA_STATS_RX_FRAGMENTED, stats->recv_fragmented},
2750 		{TIPC_NLA_STATS_RX_BUNDLES, stats->recv_bundles},
2751 		{TIPC_NLA_STATS_RX_BUNDLED, stats->recv_bundled},
2752 		{TIPC_NLA_STATS_TX_INFO, stats->sent_pkts},
2753 		{TIPC_NLA_STATS_TX_FRAGMENTS, stats->sent_fragments},
2754 		{TIPC_NLA_STATS_TX_FRAGMENTED, stats->sent_fragmented},
2755 		{TIPC_NLA_STATS_TX_BUNDLES, stats->sent_bundles},
2756 		{TIPC_NLA_STATS_TX_BUNDLED, stats->sent_bundled},
2757 		{TIPC_NLA_STATS_RX_NACKS, stats->recv_nacks},
2758 		{TIPC_NLA_STATS_RX_DEFERRED, stats->deferred_recv},
2759 		{TIPC_NLA_STATS_TX_NACKS, stats->sent_nacks},
2760 		{TIPC_NLA_STATS_TX_ACKS, stats->sent_acks},
2761 		{TIPC_NLA_STATS_RETRANSMITTED, stats->retransmitted},
2762 		{TIPC_NLA_STATS_DUPLICATES, stats->duplicates},
2763 		{TIPC_NLA_STATS_LINK_CONGS, stats->link_congs},
2764 		{TIPC_NLA_STATS_MAX_QUEUE, stats->max_queue_sz},
2765 		{TIPC_NLA_STATS_AVG_QUEUE, stats->queue_sz_counts ?
2766 			(stats->accu_queue_sz / stats->queue_sz_counts) : 0}
2767 	};
2768 
2769 	nest = nla_nest_start_noflag(skb, TIPC_NLA_LINK_STATS);
2770 	if (!nest)
2771 		return -EMSGSIZE;
2772 
2773 	for (i = 0; i <  ARRAY_SIZE(map); i++)
2774 		if (nla_put_u32(skb, map[i].key, map[i].val))
2775 			goto msg_full;
2776 
2777 	nla_nest_end(skb, nest);
2778 
2779 	return 0;
2780 msg_full:
2781 	nla_nest_cancel(skb, nest);
2782 
2783 	return -EMSGSIZE;
2784 }
2785 
2786 int tipc_nl_add_bc_link(struct net *net, struct tipc_nl_msg *msg,
2787 			struct tipc_link *bcl)
2788 {
2789 	int err;
2790 	void *hdr;
2791 	struct nlattr *attrs;
2792 	struct nlattr *prop;
2793 	u32 bc_mode = tipc_bcast_get_mode(net);
2794 	u32 bc_ratio = tipc_bcast_get_broadcast_ratio(net);
2795 
2796 	if (!bcl)
2797 		return 0;
2798 
2799 	tipc_bcast_lock(net);
2800 
2801 	hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
2802 			  NLM_F_MULTI, TIPC_NL_LINK_GET);
2803 	if (!hdr) {
2804 		tipc_bcast_unlock(net);
2805 		return -EMSGSIZE;
2806 	}
2807 
2808 	attrs = nla_nest_start_noflag(msg->skb, TIPC_NLA_LINK);
2809 	if (!attrs)
2810 		goto msg_full;
2811 
2812 	/* The broadcast link is always up */
2813 	if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
2814 		goto attr_msg_full;
2815 
2816 	if (nla_put_flag(msg->skb, TIPC_NLA_LINK_BROADCAST))
2817 		goto attr_msg_full;
2818 	if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, bcl->name))
2819 		goto attr_msg_full;
2820 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, 0))
2821 		goto attr_msg_full;
2822 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, 0))
2823 		goto attr_msg_full;
2824 
2825 	prop = nla_nest_start_noflag(msg->skb, TIPC_NLA_LINK_PROP);
2826 	if (!prop)
2827 		goto attr_msg_full;
2828 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN, bcl->max_win))
2829 		goto prop_msg_full;
2830 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_BROADCAST, bc_mode))
2831 		goto prop_msg_full;
2832 	if (bc_mode & BCLINK_MODE_SEL)
2833 		if (nla_put_u32(msg->skb, TIPC_NLA_PROP_BROADCAST_RATIO,
2834 				bc_ratio))
2835 			goto prop_msg_full;
2836 	nla_nest_end(msg->skb, prop);
2837 
2838 	err = __tipc_nl_add_bc_link_stat(msg->skb, &bcl->stats);
2839 	if (err)
2840 		goto attr_msg_full;
2841 
2842 	tipc_bcast_unlock(net);
2843 	nla_nest_end(msg->skb, attrs);
2844 	genlmsg_end(msg->skb, hdr);
2845 
2846 	return 0;
2847 
2848 prop_msg_full:
2849 	nla_nest_cancel(msg->skb, prop);
2850 attr_msg_full:
2851 	nla_nest_cancel(msg->skb, attrs);
2852 msg_full:
2853 	tipc_bcast_unlock(net);
2854 	genlmsg_cancel(msg->skb, hdr);
2855 
2856 	return -EMSGSIZE;
2857 }
2858 
2859 void tipc_link_set_tolerance(struct tipc_link *l, u32 tol,
2860 			     struct sk_buff_head *xmitq)
2861 {
2862 	l->tolerance = tol;
2863 	if (l->bc_rcvlink)
2864 		l->bc_rcvlink->tolerance = tol;
2865 	if (link_is_up(l))
2866 		tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, tol, 0, xmitq);
2867 }
2868 
2869 void tipc_link_set_prio(struct tipc_link *l, u32 prio,
2870 			struct sk_buff_head *xmitq)
2871 {
2872 	l->priority = prio;
2873 	tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, 0, prio, xmitq);
2874 }
2875 
2876 void tipc_link_set_abort_limit(struct tipc_link *l, u32 limit)
2877 {
2878 	l->abort_limit = limit;
2879 }
2880 
2881 /**
2882  * tipc_link_dump - dump TIPC link data
2883  * @l: tipc link to be dumped
2884  * @dqueues: bitmask to decide if any link queue to be dumped?
2885  *           - TIPC_DUMP_NONE: don't dump link queues
2886  *           - TIPC_DUMP_TRANSMQ: dump link transmq queue
2887  *           - TIPC_DUMP_BACKLOGQ: dump link backlog queue
2888  *           - TIPC_DUMP_DEFERDQ: dump link deferd queue
2889  *           - TIPC_DUMP_INPUTQ: dump link input queue
2890  *           - TIPC_DUMP_WAKEUP: dump link wakeup queue
2891  *           - TIPC_DUMP_ALL: dump all the link queues above
2892  * @buf: returned buffer of dump data in format
2893  */
2894 int tipc_link_dump(struct tipc_link *l, u16 dqueues, char *buf)
2895 {
2896 	int i = 0;
2897 	size_t sz = (dqueues) ? LINK_LMAX : LINK_LMIN;
2898 	struct sk_buff_head *list;
2899 	struct sk_buff *hskb, *tskb;
2900 	u32 len;
2901 
2902 	if (!l) {
2903 		i += scnprintf(buf, sz, "link data: (null)\n");
2904 		return i;
2905 	}
2906 
2907 	i += scnprintf(buf, sz, "link data: %x", l->addr);
2908 	i += scnprintf(buf + i, sz - i, " %x", l->state);
2909 	i += scnprintf(buf + i, sz - i, " %u", l->in_session);
2910 	i += scnprintf(buf + i, sz - i, " %u", l->session);
2911 	i += scnprintf(buf + i, sz - i, " %u", l->peer_session);
2912 	i += scnprintf(buf + i, sz - i, " %u", l->snd_nxt);
2913 	i += scnprintf(buf + i, sz - i, " %u", l->rcv_nxt);
2914 	i += scnprintf(buf + i, sz - i, " %u", l->snd_nxt_state);
2915 	i += scnprintf(buf + i, sz - i, " %u", l->rcv_nxt_state);
2916 	i += scnprintf(buf + i, sz - i, " %x", l->peer_caps);
2917 	i += scnprintf(buf + i, sz - i, " %u", l->silent_intv_cnt);
2918 	i += scnprintf(buf + i, sz - i, " %u", l->rst_cnt);
2919 	i += scnprintf(buf + i, sz - i, " %u", 0);
2920 	i += scnprintf(buf + i, sz - i, " %u", 0);
2921 	i += scnprintf(buf + i, sz - i, " %u", l->acked);
2922 
2923 	list = &l->transmq;
2924 	len = skb_queue_len(list);
2925 	hskb = skb_peek(list);
2926 	tskb = skb_peek_tail(list);
2927 	i += scnprintf(buf + i, sz - i, " | %u %u %u", len,
2928 		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
2929 		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
2930 
2931 	list = &l->deferdq;
2932 	len = skb_queue_len(list);
2933 	hskb = skb_peek(list);
2934 	tskb = skb_peek_tail(list);
2935 	i += scnprintf(buf + i, sz - i, " | %u %u %u", len,
2936 		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
2937 		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
2938 
2939 	list = &l->backlogq;
2940 	len = skb_queue_len(list);
2941 	hskb = skb_peek(list);
2942 	tskb = skb_peek_tail(list);
2943 	i += scnprintf(buf + i, sz - i, " | %u %u %u", len,
2944 		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
2945 		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
2946 
2947 	list = l->inputq;
2948 	len = skb_queue_len(list);
2949 	hskb = skb_peek(list);
2950 	tskb = skb_peek_tail(list);
2951 	i += scnprintf(buf + i, sz - i, " | %u %u %u\n", len,
2952 		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
2953 		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
2954 
2955 	if (dqueues & TIPC_DUMP_TRANSMQ) {
2956 		i += scnprintf(buf + i, sz - i, "transmq: ");
2957 		i += tipc_list_dump(&l->transmq, false, buf + i);
2958 	}
2959 	if (dqueues & TIPC_DUMP_BACKLOGQ) {
2960 		i += scnprintf(buf + i, sz - i,
2961 			       "backlogq: <%u %u %u %u %u>, ",
2962 			       l->backlog[TIPC_LOW_IMPORTANCE].len,
2963 			       l->backlog[TIPC_MEDIUM_IMPORTANCE].len,
2964 			       l->backlog[TIPC_HIGH_IMPORTANCE].len,
2965 			       l->backlog[TIPC_CRITICAL_IMPORTANCE].len,
2966 			       l->backlog[TIPC_SYSTEM_IMPORTANCE].len);
2967 		i += tipc_list_dump(&l->backlogq, false, buf + i);
2968 	}
2969 	if (dqueues & TIPC_DUMP_DEFERDQ) {
2970 		i += scnprintf(buf + i, sz - i, "deferdq: ");
2971 		i += tipc_list_dump(&l->deferdq, false, buf + i);
2972 	}
2973 	if (dqueues & TIPC_DUMP_INPUTQ) {
2974 		i += scnprintf(buf + i, sz - i, "inputq: ");
2975 		i += tipc_list_dump(l->inputq, false, buf + i);
2976 	}
2977 	if (dqueues & TIPC_DUMP_WAKEUP) {
2978 		i += scnprintf(buf + i, sz - i, "wakeup: ");
2979 		i += tipc_list_dump(&l->wakeupq, false, buf + i);
2980 	}
2981 
2982 	return i;
2983 }
2984