xref: /openbmc/linux/net/tipc/link.c (revision 0ad53fe3)
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 struct net *tipc_link_net(struct tipc_link *l)
376 {
377 	return l->net;
378 }
379 
380 void tipc_link_update_caps(struct tipc_link *l, u16 capabilities)
381 {
382 	l->peer_caps = capabilities;
383 }
384 
385 void tipc_link_add_bc_peer(struct tipc_link *snd_l,
386 			   struct tipc_link *uc_l,
387 			   struct sk_buff_head *xmitq)
388 {
389 	struct tipc_link *rcv_l = uc_l->bc_rcvlink;
390 
391 	snd_l->ackers++;
392 	rcv_l->acked = snd_l->snd_nxt - 1;
393 	snd_l->state = LINK_ESTABLISHED;
394 	tipc_link_build_bc_init_msg(uc_l, xmitq);
395 }
396 
397 void tipc_link_remove_bc_peer(struct tipc_link *snd_l,
398 			      struct tipc_link *rcv_l,
399 			      struct sk_buff_head *xmitq)
400 {
401 	u16 ack = snd_l->snd_nxt - 1;
402 
403 	snd_l->ackers--;
404 	rcv_l->bc_peer_is_up = true;
405 	rcv_l->state = LINK_ESTABLISHED;
406 	tipc_link_bc_ack_rcv(rcv_l, ack, 0, NULL, xmitq, NULL);
407 	trace_tipc_link_reset(rcv_l, TIPC_DUMP_ALL, "bclink removed!");
408 	tipc_link_reset(rcv_l);
409 	rcv_l->state = LINK_RESET;
410 	if (!snd_l->ackers) {
411 		trace_tipc_link_reset(snd_l, TIPC_DUMP_ALL, "zero ackers!");
412 		tipc_link_reset(snd_l);
413 		snd_l->state = LINK_RESET;
414 		__skb_queue_purge(xmitq);
415 	}
416 }
417 
418 int tipc_link_bc_peers(struct tipc_link *l)
419 {
420 	return l->ackers;
421 }
422 
423 static u16 link_bc_rcv_gap(struct tipc_link *l)
424 {
425 	struct sk_buff *skb = skb_peek(&l->deferdq);
426 	u16 gap = 0;
427 
428 	if (more(l->snd_nxt, l->rcv_nxt))
429 		gap = l->snd_nxt - l->rcv_nxt;
430 	if (skb)
431 		gap = buf_seqno(skb) - l->rcv_nxt;
432 	return gap;
433 }
434 
435 void tipc_link_set_mtu(struct tipc_link *l, int mtu)
436 {
437 	l->mtu = mtu;
438 }
439 
440 int tipc_link_mtu(struct tipc_link *l)
441 {
442 	return l->mtu;
443 }
444 
445 int tipc_link_mss(struct tipc_link *l)
446 {
447 #ifdef CONFIG_TIPC_CRYPTO
448 	return l->mtu - INT_H_SIZE - EMSG_OVERHEAD;
449 #else
450 	return l->mtu - INT_H_SIZE;
451 #endif
452 }
453 
454 u16 tipc_link_rcv_nxt(struct tipc_link *l)
455 {
456 	return l->rcv_nxt;
457 }
458 
459 u16 tipc_link_acked(struct tipc_link *l)
460 {
461 	return l->acked;
462 }
463 
464 char *tipc_link_name(struct tipc_link *l)
465 {
466 	return l->name;
467 }
468 
469 u32 tipc_link_state(struct tipc_link *l)
470 {
471 	return l->state;
472 }
473 
474 /**
475  * tipc_link_create - create a new link
476  * @net: pointer to associated network namespace
477  * @if_name: associated interface name
478  * @bearer_id: id (index) of associated bearer
479  * @tolerance: link tolerance to be used by link
480  * @net_plane: network plane (A,B,c..) this link belongs to
481  * @mtu: mtu to be advertised by link
482  * @priority: priority to be used by link
483  * @min_win: minimal send window to be used by link
484  * @max_win: maximal send window to be used by link
485  * @session: session to be used by link
486  * @peer: node id of peer node
487  * @peer_caps: bitmap describing peer node capabilities
488  * @bc_sndlink: the namespace global link used for broadcast sending
489  * @bc_rcvlink: the peer specific link used for broadcast reception
490  * @inputq: queue to put messages ready for delivery
491  * @namedq: queue to put binding table update messages ready for delivery
492  * @link: return value, pointer to put the created link
493  * @self: local unicast link id
494  * @peer_id: 128-bit ID of peer
495  *
496  * Return: true if link was created, otherwise false
497  */
498 bool tipc_link_create(struct net *net, char *if_name, int bearer_id,
499 		      int tolerance, char net_plane, u32 mtu, int priority,
500 		      u32 min_win, u32 max_win, u32 session, u32 self,
501 		      u32 peer, u8 *peer_id, u16 peer_caps,
502 		      struct tipc_link *bc_sndlink,
503 		      struct tipc_link *bc_rcvlink,
504 		      struct sk_buff_head *inputq,
505 		      struct sk_buff_head *namedq,
506 		      struct tipc_link **link)
507 {
508 	char peer_str[NODE_ID_STR_LEN] = {0,};
509 	char self_str[NODE_ID_STR_LEN] = {0,};
510 	struct tipc_link *l;
511 
512 	l = kzalloc(sizeof(*l), GFP_ATOMIC);
513 	if (!l)
514 		return false;
515 	*link = l;
516 	l->session = session;
517 
518 	/* Set link name for unicast links only */
519 	if (peer_id) {
520 		tipc_nodeid2string(self_str, tipc_own_id(net));
521 		if (strlen(self_str) > 16)
522 			sprintf(self_str, "%x", self);
523 		tipc_nodeid2string(peer_str, peer_id);
524 		if (strlen(peer_str) > 16)
525 			sprintf(peer_str, "%x", peer);
526 	}
527 	/* Peer i/f name will be completed by reset/activate message */
528 	snprintf(l->name, sizeof(l->name), "%s:%s-%s:unknown",
529 		 self_str, if_name, peer_str);
530 
531 	strcpy(l->if_name, if_name);
532 	l->addr = peer;
533 	l->peer_caps = peer_caps;
534 	l->net = net;
535 	l->in_session = false;
536 	l->bearer_id = bearer_id;
537 	l->tolerance = tolerance;
538 	if (bc_rcvlink)
539 		bc_rcvlink->tolerance = tolerance;
540 	l->net_plane = net_plane;
541 	l->advertised_mtu = mtu;
542 	l->mtu = mtu;
543 	l->priority = priority;
544 	tipc_link_set_queue_limits(l, min_win, max_win);
545 	l->ackers = 1;
546 	l->bc_sndlink = bc_sndlink;
547 	l->bc_rcvlink = bc_rcvlink;
548 	l->inputq = inputq;
549 	l->namedq = namedq;
550 	l->state = LINK_RESETTING;
551 	__skb_queue_head_init(&l->transmq);
552 	__skb_queue_head_init(&l->backlogq);
553 	__skb_queue_head_init(&l->deferdq);
554 	__skb_queue_head_init(&l->failover_deferdq);
555 	skb_queue_head_init(&l->wakeupq);
556 	skb_queue_head_init(l->inputq);
557 	return true;
558 }
559 
560 /**
561  * tipc_link_bc_create - create new link to be used for broadcast
562  * @net: pointer to associated network namespace
563  * @mtu: mtu to be used initially if no peers
564  * @min_win: minimal send window to be used by link
565  * @max_win: maximal send window to be used by link
566  * @inputq: queue to put messages ready for delivery
567  * @namedq: queue to put binding table update messages ready for delivery
568  * @link: return value, pointer to put the created link
569  * @ownnode: identity of own node
570  * @peer: node id of peer node
571  * @peer_id: 128-bit ID of peer
572  * @peer_caps: bitmap describing peer node capabilities
573  * @bc_sndlink: the namespace global link used for broadcast sending
574  *
575  * Return: true if link was created, otherwise false
576  */
577 bool tipc_link_bc_create(struct net *net, u32 ownnode, u32 peer, u8 *peer_id,
578 			 int mtu, u32 min_win, u32 max_win, u16 peer_caps,
579 			 struct sk_buff_head *inputq,
580 			 struct sk_buff_head *namedq,
581 			 struct tipc_link *bc_sndlink,
582 			 struct tipc_link **link)
583 {
584 	struct tipc_link *l;
585 
586 	if (!tipc_link_create(net, "", MAX_BEARERS, 0, 'Z', mtu, 0, min_win,
587 			      max_win, 0, ownnode, peer, NULL, peer_caps,
588 			      bc_sndlink, NULL, inputq, namedq, link))
589 		return false;
590 
591 	l = *link;
592 	if (peer_id) {
593 		char peer_str[NODE_ID_STR_LEN] = {0,};
594 
595 		tipc_nodeid2string(peer_str, peer_id);
596 		if (strlen(peer_str) > 16)
597 			sprintf(peer_str, "%x", peer);
598 		/* Broadcast receiver link name: "broadcast-link:<peer>" */
599 		snprintf(l->name, sizeof(l->name), "%s:%s", tipc_bclink_name,
600 			 peer_str);
601 	} else {
602 		strcpy(l->name, tipc_bclink_name);
603 	}
604 	trace_tipc_link_reset(l, TIPC_DUMP_ALL, "bclink created!");
605 	tipc_link_reset(l);
606 	l->state = LINK_RESET;
607 	l->ackers = 0;
608 	l->bc_rcvlink = l;
609 
610 	/* Broadcast send link is always up */
611 	if (link_is_bc_sndlink(l))
612 		l->state = LINK_ESTABLISHED;
613 
614 	/* Disable replicast if even a single peer doesn't support it */
615 	if (link_is_bc_rcvlink(l) && !(peer_caps & TIPC_BCAST_RCAST))
616 		tipc_bcast_toggle_rcast(net, false);
617 
618 	return true;
619 }
620 
621 /**
622  * tipc_link_fsm_evt - link finite state machine
623  * @l: pointer to link
624  * @evt: state machine event to be processed
625  */
626 int tipc_link_fsm_evt(struct tipc_link *l, int evt)
627 {
628 	int rc = 0;
629 	int old_state = l->state;
630 
631 	switch (l->state) {
632 	case LINK_RESETTING:
633 		switch (evt) {
634 		case LINK_PEER_RESET_EVT:
635 			l->state = LINK_PEER_RESET;
636 			break;
637 		case LINK_RESET_EVT:
638 			l->state = LINK_RESET;
639 			break;
640 		case LINK_FAILURE_EVT:
641 		case LINK_FAILOVER_BEGIN_EVT:
642 		case LINK_ESTABLISH_EVT:
643 		case LINK_FAILOVER_END_EVT:
644 		case LINK_SYNCH_BEGIN_EVT:
645 		case LINK_SYNCH_END_EVT:
646 		default:
647 			goto illegal_evt;
648 		}
649 		break;
650 	case LINK_RESET:
651 		switch (evt) {
652 		case LINK_PEER_RESET_EVT:
653 			l->state = LINK_ESTABLISHING;
654 			break;
655 		case LINK_FAILOVER_BEGIN_EVT:
656 			l->state = LINK_FAILINGOVER;
657 			break;
658 		case LINK_FAILURE_EVT:
659 		case LINK_RESET_EVT:
660 		case LINK_ESTABLISH_EVT:
661 		case LINK_FAILOVER_END_EVT:
662 			break;
663 		case LINK_SYNCH_BEGIN_EVT:
664 		case LINK_SYNCH_END_EVT:
665 		default:
666 			goto illegal_evt;
667 		}
668 		break;
669 	case LINK_PEER_RESET:
670 		switch (evt) {
671 		case LINK_RESET_EVT:
672 			l->state = LINK_ESTABLISHING;
673 			break;
674 		case LINK_PEER_RESET_EVT:
675 		case LINK_ESTABLISH_EVT:
676 		case LINK_FAILURE_EVT:
677 			break;
678 		case LINK_SYNCH_BEGIN_EVT:
679 		case LINK_SYNCH_END_EVT:
680 		case LINK_FAILOVER_BEGIN_EVT:
681 		case LINK_FAILOVER_END_EVT:
682 		default:
683 			goto illegal_evt;
684 		}
685 		break;
686 	case LINK_FAILINGOVER:
687 		switch (evt) {
688 		case LINK_FAILOVER_END_EVT:
689 			l->state = LINK_RESET;
690 			break;
691 		case LINK_PEER_RESET_EVT:
692 		case LINK_RESET_EVT:
693 		case LINK_ESTABLISH_EVT:
694 		case LINK_FAILURE_EVT:
695 			break;
696 		case LINK_FAILOVER_BEGIN_EVT:
697 		case LINK_SYNCH_BEGIN_EVT:
698 		case LINK_SYNCH_END_EVT:
699 		default:
700 			goto illegal_evt;
701 		}
702 		break;
703 	case LINK_ESTABLISHING:
704 		switch (evt) {
705 		case LINK_ESTABLISH_EVT:
706 			l->state = LINK_ESTABLISHED;
707 			break;
708 		case LINK_FAILOVER_BEGIN_EVT:
709 			l->state = LINK_FAILINGOVER;
710 			break;
711 		case LINK_RESET_EVT:
712 			l->state = LINK_RESET;
713 			break;
714 		case LINK_FAILURE_EVT:
715 		case LINK_PEER_RESET_EVT:
716 		case LINK_SYNCH_BEGIN_EVT:
717 		case LINK_FAILOVER_END_EVT:
718 			break;
719 		case LINK_SYNCH_END_EVT:
720 		default:
721 			goto illegal_evt;
722 		}
723 		break;
724 	case LINK_ESTABLISHED:
725 		switch (evt) {
726 		case LINK_PEER_RESET_EVT:
727 			l->state = LINK_PEER_RESET;
728 			rc |= TIPC_LINK_DOWN_EVT;
729 			break;
730 		case LINK_FAILURE_EVT:
731 			l->state = LINK_RESETTING;
732 			rc |= TIPC_LINK_DOWN_EVT;
733 			break;
734 		case LINK_RESET_EVT:
735 			l->state = LINK_RESET;
736 			break;
737 		case LINK_ESTABLISH_EVT:
738 		case LINK_SYNCH_END_EVT:
739 			break;
740 		case LINK_SYNCH_BEGIN_EVT:
741 			l->state = LINK_SYNCHING;
742 			break;
743 		case LINK_FAILOVER_BEGIN_EVT:
744 		case LINK_FAILOVER_END_EVT:
745 		default:
746 			goto illegal_evt;
747 		}
748 		break;
749 	case LINK_SYNCHING:
750 		switch (evt) {
751 		case LINK_PEER_RESET_EVT:
752 			l->state = LINK_PEER_RESET;
753 			rc |= TIPC_LINK_DOWN_EVT;
754 			break;
755 		case LINK_FAILURE_EVT:
756 			l->state = LINK_RESETTING;
757 			rc |= TIPC_LINK_DOWN_EVT;
758 			break;
759 		case LINK_RESET_EVT:
760 			l->state = LINK_RESET;
761 			break;
762 		case LINK_ESTABLISH_EVT:
763 		case LINK_SYNCH_BEGIN_EVT:
764 			break;
765 		case LINK_SYNCH_END_EVT:
766 			l->state = LINK_ESTABLISHED;
767 			break;
768 		case LINK_FAILOVER_BEGIN_EVT:
769 		case LINK_FAILOVER_END_EVT:
770 		default:
771 			goto illegal_evt;
772 		}
773 		break;
774 	default:
775 		pr_err("Unknown FSM state %x in %s\n", l->state, l->name);
776 	}
777 	trace_tipc_link_fsm(l->name, old_state, l->state, evt);
778 	return rc;
779 illegal_evt:
780 	pr_err("Illegal FSM event %x in state %x on link %s\n",
781 	       evt, l->state, l->name);
782 	trace_tipc_link_fsm(l->name, old_state, l->state, evt);
783 	return rc;
784 }
785 
786 /* link_profile_stats - update statistical profiling of traffic
787  */
788 static void link_profile_stats(struct tipc_link *l)
789 {
790 	struct sk_buff *skb;
791 	struct tipc_msg *msg;
792 	int length;
793 
794 	/* Update counters used in statistical profiling of send traffic */
795 	l->stats.accu_queue_sz += skb_queue_len(&l->transmq);
796 	l->stats.queue_sz_counts++;
797 
798 	skb = skb_peek(&l->transmq);
799 	if (!skb)
800 		return;
801 	msg = buf_msg(skb);
802 	length = msg_size(msg);
803 
804 	if (msg_user(msg) == MSG_FRAGMENTER) {
805 		if (msg_type(msg) != FIRST_FRAGMENT)
806 			return;
807 		length = msg_size(msg_inner_hdr(msg));
808 	}
809 	l->stats.msg_lengths_total += length;
810 	l->stats.msg_length_counts++;
811 	if (length <= 64)
812 		l->stats.msg_length_profile[0]++;
813 	else if (length <= 256)
814 		l->stats.msg_length_profile[1]++;
815 	else if (length <= 1024)
816 		l->stats.msg_length_profile[2]++;
817 	else if (length <= 4096)
818 		l->stats.msg_length_profile[3]++;
819 	else if (length <= 16384)
820 		l->stats.msg_length_profile[4]++;
821 	else if (length <= 32768)
822 		l->stats.msg_length_profile[5]++;
823 	else
824 		l->stats.msg_length_profile[6]++;
825 }
826 
827 /**
828  * tipc_link_too_silent - check if link is "too silent"
829  * @l: tipc link to be checked
830  *
831  * Return: true if the link 'silent_intv_cnt' is about to reach the
832  * 'abort_limit' value, otherwise false
833  */
834 bool tipc_link_too_silent(struct tipc_link *l)
835 {
836 	return (l->silent_intv_cnt + 2 > l->abort_limit);
837 }
838 
839 /* tipc_link_timeout - perform periodic task as instructed from node timeout
840  */
841 int tipc_link_timeout(struct tipc_link *l, struct sk_buff_head *xmitq)
842 {
843 	int mtyp = 0;
844 	int rc = 0;
845 	bool state = false;
846 	bool probe = false;
847 	bool setup = false;
848 	u16 bc_snt = l->bc_sndlink->snd_nxt - 1;
849 	u16 bc_acked = l->bc_rcvlink->acked;
850 	struct tipc_mon_state *mstate = &l->mon_state;
851 
852 	trace_tipc_link_timeout(l, TIPC_DUMP_NONE, " ");
853 	trace_tipc_link_too_silent(l, TIPC_DUMP_ALL, " ");
854 	switch (l->state) {
855 	case LINK_ESTABLISHED:
856 	case LINK_SYNCHING:
857 		mtyp = STATE_MSG;
858 		link_profile_stats(l);
859 		tipc_mon_get_state(l->net, l->addr, mstate, l->bearer_id);
860 		if (mstate->reset || (l->silent_intv_cnt > l->abort_limit))
861 			return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
862 		state = bc_acked != bc_snt;
863 		state |= l->bc_rcvlink->rcv_unacked;
864 		state |= l->rcv_unacked;
865 		state |= !skb_queue_empty(&l->transmq);
866 		probe = mstate->probing;
867 		probe |= l->silent_intv_cnt;
868 		if (probe || mstate->monitoring)
869 			l->silent_intv_cnt++;
870 		probe |= !skb_queue_empty(&l->deferdq);
871 		if (l->snd_nxt == l->checkpoint) {
872 			tipc_link_update_cwin(l, 0, 0);
873 			probe = true;
874 		}
875 		l->checkpoint = l->snd_nxt;
876 		break;
877 	case LINK_RESET:
878 		setup = l->rst_cnt++ <= 4;
879 		setup |= !(l->rst_cnt % 16);
880 		mtyp = RESET_MSG;
881 		break;
882 	case LINK_ESTABLISHING:
883 		setup = true;
884 		mtyp = ACTIVATE_MSG;
885 		break;
886 	case LINK_PEER_RESET:
887 	case LINK_RESETTING:
888 	case LINK_FAILINGOVER:
889 		break;
890 	default:
891 		break;
892 	}
893 
894 	if (state || probe || setup)
895 		tipc_link_build_proto_msg(l, mtyp, probe, 0, 0, 0, 0, xmitq);
896 
897 	return rc;
898 }
899 
900 /**
901  * link_schedule_user - schedule a message sender for wakeup after congestion
902  * @l: congested link
903  * @hdr: header of message that is being sent
904  * Create pseudo msg to send back to user when congestion abates
905  */
906 static int link_schedule_user(struct tipc_link *l, struct tipc_msg *hdr)
907 {
908 	u32 dnode = tipc_own_addr(l->net);
909 	u32 dport = msg_origport(hdr);
910 	struct sk_buff *skb;
911 
912 	/* Create and schedule wakeup pseudo message */
913 	skb = tipc_msg_create(SOCK_WAKEUP, 0, INT_H_SIZE, 0,
914 			      dnode, l->addr, dport, 0, 0);
915 	if (!skb)
916 		return -ENOBUFS;
917 	msg_set_dest_droppable(buf_msg(skb), true);
918 	TIPC_SKB_CB(skb)->chain_imp = msg_importance(hdr);
919 	skb_queue_tail(&l->wakeupq, skb);
920 	l->stats.link_congs++;
921 	trace_tipc_link_conges(l, TIPC_DUMP_ALL, "wakeup scheduled!");
922 	return -ELINKCONG;
923 }
924 
925 /**
926  * link_prepare_wakeup - prepare users for wakeup after congestion
927  * @l: congested link
928  * Wake up a number of waiting users, as permitted by available space
929  * in the send queue
930  */
931 static void link_prepare_wakeup(struct tipc_link *l)
932 {
933 	struct sk_buff_head *wakeupq = &l->wakeupq;
934 	struct sk_buff_head *inputq = l->inputq;
935 	struct sk_buff *skb, *tmp;
936 	struct sk_buff_head tmpq;
937 	int avail[5] = {0,};
938 	int imp = 0;
939 
940 	__skb_queue_head_init(&tmpq);
941 
942 	for (; imp <= TIPC_SYSTEM_IMPORTANCE; imp++)
943 		avail[imp] = l->backlog[imp].limit - l->backlog[imp].len;
944 
945 	skb_queue_walk_safe(wakeupq, skb, tmp) {
946 		imp = TIPC_SKB_CB(skb)->chain_imp;
947 		if (avail[imp] <= 0)
948 			continue;
949 		avail[imp]--;
950 		__skb_unlink(skb, wakeupq);
951 		__skb_queue_tail(&tmpq, skb);
952 	}
953 
954 	spin_lock_bh(&inputq->lock);
955 	skb_queue_splice_tail(&tmpq, inputq);
956 	spin_unlock_bh(&inputq->lock);
957 
958 }
959 
960 /**
961  * tipc_link_set_skb_retransmit_time - set the time at which retransmission of
962  *                                     the given skb should be next attempted
963  * @skb: skb to set a future retransmission time for
964  * @l: link the skb will be transmitted on
965  */
966 static void tipc_link_set_skb_retransmit_time(struct sk_buff *skb,
967 					      struct tipc_link *l)
968 {
969 	if (link_is_bc_sndlink(l))
970 		TIPC_SKB_CB(skb)->nxt_retr = TIPC_BC_RETR_LIM;
971 	else
972 		TIPC_SKB_CB(skb)->nxt_retr = TIPC_UC_RETR_TIME;
973 }
974 
975 void tipc_link_reset(struct tipc_link *l)
976 {
977 	struct sk_buff_head list;
978 	u32 imp;
979 
980 	__skb_queue_head_init(&list);
981 
982 	l->in_session = false;
983 	/* Force re-synch of peer session number before establishing */
984 	l->peer_session--;
985 	l->session++;
986 	l->mtu = l->advertised_mtu;
987 
988 	spin_lock_bh(&l->wakeupq.lock);
989 	skb_queue_splice_init(&l->wakeupq, &list);
990 	spin_unlock_bh(&l->wakeupq.lock);
991 
992 	spin_lock_bh(&l->inputq->lock);
993 	skb_queue_splice_init(&list, l->inputq);
994 	spin_unlock_bh(&l->inputq->lock);
995 
996 	__skb_queue_purge(&l->transmq);
997 	__skb_queue_purge(&l->deferdq);
998 	__skb_queue_purge(&l->backlogq);
999 	__skb_queue_purge(&l->failover_deferdq);
1000 	for (imp = 0; imp <= TIPC_SYSTEM_IMPORTANCE; imp++) {
1001 		l->backlog[imp].len = 0;
1002 		l->backlog[imp].target_bskb = NULL;
1003 	}
1004 	kfree_skb(l->reasm_buf);
1005 	kfree_skb(l->reasm_tnlmsg);
1006 	kfree_skb(l->failover_reasm_skb);
1007 	l->reasm_buf = NULL;
1008 	l->reasm_tnlmsg = NULL;
1009 	l->failover_reasm_skb = NULL;
1010 	l->rcv_unacked = 0;
1011 	l->snd_nxt = 1;
1012 	l->rcv_nxt = 1;
1013 	l->snd_nxt_state = 1;
1014 	l->rcv_nxt_state = 1;
1015 	l->acked = 0;
1016 	l->last_gap = 0;
1017 	kfree(l->last_ga);
1018 	l->last_ga = NULL;
1019 	l->silent_intv_cnt = 0;
1020 	l->rst_cnt = 0;
1021 	l->bc_peer_is_up = false;
1022 	memset(&l->mon_state, 0, sizeof(l->mon_state));
1023 	tipc_link_reset_stats(l);
1024 }
1025 
1026 /**
1027  * tipc_link_xmit(): enqueue buffer list according to queue situation
1028  * @l: link to use
1029  * @list: chain of buffers containing message
1030  * @xmitq: returned list of packets to be sent by caller
1031  *
1032  * Consumes the buffer chain.
1033  * Messages at TIPC_SYSTEM_IMPORTANCE are always accepted
1034  * Return: 0 if success, or errno: -ELINKCONG, -EMSGSIZE or -ENOBUFS
1035  */
1036 int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *list,
1037 		   struct sk_buff_head *xmitq)
1038 {
1039 	struct sk_buff_head *backlogq = &l->backlogq;
1040 	struct sk_buff_head *transmq = &l->transmq;
1041 	struct sk_buff *skb, *_skb;
1042 	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
1043 	u16 ack = l->rcv_nxt - 1;
1044 	u16 seqno = l->snd_nxt;
1045 	int pkt_cnt = skb_queue_len(list);
1046 	unsigned int mss = tipc_link_mss(l);
1047 	unsigned int cwin = l->window;
1048 	unsigned int mtu = l->mtu;
1049 	struct tipc_msg *hdr;
1050 	bool new_bundle;
1051 	int rc = 0;
1052 	int imp;
1053 
1054 	if (pkt_cnt <= 0)
1055 		return 0;
1056 
1057 	hdr = buf_msg(skb_peek(list));
1058 	if (unlikely(msg_size(hdr) > mtu)) {
1059 		pr_warn("Too large msg, purging xmit list %d %d %d %d %d!\n",
1060 			skb_queue_len(list), msg_user(hdr),
1061 			msg_type(hdr), msg_size(hdr), mtu);
1062 		__skb_queue_purge(list);
1063 		return -EMSGSIZE;
1064 	}
1065 
1066 	imp = msg_importance(hdr);
1067 	/* Allow oversubscription of one data msg per source at congestion */
1068 	if (unlikely(l->backlog[imp].len >= l->backlog[imp].limit)) {
1069 		if (imp == TIPC_SYSTEM_IMPORTANCE) {
1070 			pr_warn("%s<%s>, link overflow", link_rst_msg, l->name);
1071 			return -ENOBUFS;
1072 		}
1073 		rc = link_schedule_user(l, hdr);
1074 	}
1075 
1076 	if (pkt_cnt > 1) {
1077 		l->stats.sent_fragmented++;
1078 		l->stats.sent_fragments += pkt_cnt;
1079 	}
1080 
1081 	/* Prepare each packet for sending, and add to relevant queue: */
1082 	while ((skb = __skb_dequeue(list))) {
1083 		if (likely(skb_queue_len(transmq) < cwin)) {
1084 			hdr = buf_msg(skb);
1085 			msg_set_seqno(hdr, seqno);
1086 			msg_set_ack(hdr, ack);
1087 			msg_set_bcast_ack(hdr, bc_ack);
1088 			_skb = skb_clone(skb, GFP_ATOMIC);
1089 			if (!_skb) {
1090 				kfree_skb(skb);
1091 				__skb_queue_purge(list);
1092 				return -ENOBUFS;
1093 			}
1094 			__skb_queue_tail(transmq, skb);
1095 			tipc_link_set_skb_retransmit_time(skb, l);
1096 			__skb_queue_tail(xmitq, _skb);
1097 			TIPC_SKB_CB(skb)->ackers = l->ackers;
1098 			l->rcv_unacked = 0;
1099 			l->stats.sent_pkts++;
1100 			seqno++;
1101 			continue;
1102 		}
1103 		if (tipc_msg_try_bundle(l->backlog[imp].target_bskb, &skb,
1104 					mss, l->addr, &new_bundle)) {
1105 			if (skb) {
1106 				/* Keep a ref. to the skb for next try */
1107 				l->backlog[imp].target_bskb = skb;
1108 				l->backlog[imp].len++;
1109 				__skb_queue_tail(backlogq, skb);
1110 			} else {
1111 				if (new_bundle) {
1112 					l->stats.sent_bundles++;
1113 					l->stats.sent_bundled++;
1114 				}
1115 				l->stats.sent_bundled++;
1116 			}
1117 			continue;
1118 		}
1119 		l->backlog[imp].target_bskb = NULL;
1120 		l->backlog[imp].len += (1 + skb_queue_len(list));
1121 		__skb_queue_tail(backlogq, skb);
1122 		skb_queue_splice_tail_init(list, backlogq);
1123 	}
1124 	l->snd_nxt = seqno;
1125 	return rc;
1126 }
1127 
1128 static void tipc_link_update_cwin(struct tipc_link *l, int released,
1129 				  bool retransmitted)
1130 {
1131 	int bklog_len = skb_queue_len(&l->backlogq);
1132 	struct sk_buff_head *txq = &l->transmq;
1133 	int txq_len = skb_queue_len(txq);
1134 	u16 cwin = l->window;
1135 
1136 	/* Enter fast recovery */
1137 	if (unlikely(retransmitted)) {
1138 		l->ssthresh = max_t(u16, l->window / 2, 300);
1139 		l->window = min_t(u16, l->ssthresh, l->window);
1140 		return;
1141 	}
1142 	/* Enter slow start */
1143 	if (unlikely(!released)) {
1144 		l->ssthresh = max_t(u16, l->window / 2, 300);
1145 		l->window = l->min_win;
1146 		return;
1147 	}
1148 	/* Don't increase window if no pressure on the transmit queue */
1149 	if (txq_len + bklog_len < cwin)
1150 		return;
1151 
1152 	/* Don't increase window if there are holes the transmit queue */
1153 	if (txq_len && l->snd_nxt - buf_seqno(skb_peek(txq)) != txq_len)
1154 		return;
1155 
1156 	l->cong_acks += released;
1157 
1158 	/* Slow start  */
1159 	if (cwin <= l->ssthresh) {
1160 		l->window = min_t(u16, cwin + released, l->max_win);
1161 		return;
1162 	}
1163 	/* Congestion avoidance */
1164 	if (l->cong_acks < cwin)
1165 		return;
1166 	l->window = min_t(u16, ++cwin, l->max_win);
1167 	l->cong_acks = 0;
1168 }
1169 
1170 static void tipc_link_advance_backlog(struct tipc_link *l,
1171 				      struct sk_buff_head *xmitq)
1172 {
1173 	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
1174 	struct sk_buff_head *txq = &l->transmq;
1175 	struct sk_buff *skb, *_skb;
1176 	u16 ack = l->rcv_nxt - 1;
1177 	u16 seqno = l->snd_nxt;
1178 	struct tipc_msg *hdr;
1179 	u16 cwin = l->window;
1180 	u32 imp;
1181 
1182 	while (skb_queue_len(txq) < cwin) {
1183 		skb = skb_peek(&l->backlogq);
1184 		if (!skb)
1185 			break;
1186 		_skb = skb_clone(skb, GFP_ATOMIC);
1187 		if (!_skb)
1188 			break;
1189 		__skb_dequeue(&l->backlogq);
1190 		hdr = buf_msg(skb);
1191 		imp = msg_importance(hdr);
1192 		l->backlog[imp].len--;
1193 		if (unlikely(skb == l->backlog[imp].target_bskb))
1194 			l->backlog[imp].target_bskb = NULL;
1195 		__skb_queue_tail(&l->transmq, skb);
1196 		tipc_link_set_skb_retransmit_time(skb, l);
1197 
1198 		__skb_queue_tail(xmitq, _skb);
1199 		TIPC_SKB_CB(skb)->ackers = l->ackers;
1200 		msg_set_seqno(hdr, seqno);
1201 		msg_set_ack(hdr, ack);
1202 		msg_set_bcast_ack(hdr, bc_ack);
1203 		l->rcv_unacked = 0;
1204 		l->stats.sent_pkts++;
1205 		seqno++;
1206 	}
1207 	l->snd_nxt = seqno;
1208 }
1209 
1210 /**
1211  * link_retransmit_failure() - Detect repeated retransmit failures
1212  * @l: tipc link sender
1213  * @r: tipc link receiver (= l in case of unicast)
1214  * @rc: returned code
1215  *
1216  * Return: true if the repeated retransmit failures happens, otherwise
1217  * false
1218  */
1219 static bool link_retransmit_failure(struct tipc_link *l, struct tipc_link *r,
1220 				    int *rc)
1221 {
1222 	struct sk_buff *skb = skb_peek(&l->transmq);
1223 	struct tipc_msg *hdr;
1224 
1225 	if (!skb)
1226 		return false;
1227 
1228 	if (!TIPC_SKB_CB(skb)->retr_cnt)
1229 		return false;
1230 
1231 	if (!time_after(jiffies, TIPC_SKB_CB(skb)->retr_stamp +
1232 			msecs_to_jiffies(r->tolerance * 10)))
1233 		return false;
1234 
1235 	hdr = buf_msg(skb);
1236 	if (link_is_bc_sndlink(l) && !less(r->acked, msg_seqno(hdr)))
1237 		return false;
1238 
1239 	pr_warn("Retransmission failure on link <%s>\n", l->name);
1240 	link_print(l, "State of link ");
1241 	pr_info("Failed msg: usr %u, typ %u, len %u, err %u\n",
1242 		msg_user(hdr), msg_type(hdr), msg_size(hdr), msg_errcode(hdr));
1243 	pr_info("sqno %u, prev: %x, dest: %x\n",
1244 		msg_seqno(hdr), msg_prevnode(hdr), msg_destnode(hdr));
1245 	pr_info("retr_stamp %d, retr_cnt %d\n",
1246 		jiffies_to_msecs(TIPC_SKB_CB(skb)->retr_stamp),
1247 		TIPC_SKB_CB(skb)->retr_cnt);
1248 
1249 	trace_tipc_list_dump(&l->transmq, true, "retrans failure!");
1250 	trace_tipc_link_dump(l, TIPC_DUMP_NONE, "retrans failure!");
1251 	trace_tipc_link_dump(r, TIPC_DUMP_NONE, "retrans failure!");
1252 
1253 	if (link_is_bc_sndlink(l)) {
1254 		r->state = LINK_RESET;
1255 		*rc |= TIPC_LINK_DOWN_EVT;
1256 	} else {
1257 		*rc |= tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1258 	}
1259 
1260 	return true;
1261 }
1262 
1263 /* tipc_data_input - deliver data and name distr msgs to upper layer
1264  *
1265  * Consumes buffer if message is of right type
1266  * Node lock must be held
1267  */
1268 static bool tipc_data_input(struct tipc_link *l, struct sk_buff *skb,
1269 			    struct sk_buff_head *inputq)
1270 {
1271 	struct sk_buff_head *mc_inputq = l->bc_rcvlink->inputq;
1272 	struct tipc_msg *hdr = buf_msg(skb);
1273 
1274 	switch (msg_user(hdr)) {
1275 	case TIPC_LOW_IMPORTANCE:
1276 	case TIPC_MEDIUM_IMPORTANCE:
1277 	case TIPC_HIGH_IMPORTANCE:
1278 	case TIPC_CRITICAL_IMPORTANCE:
1279 		if (unlikely(msg_in_group(hdr) || msg_mcast(hdr))) {
1280 			skb_queue_tail(mc_inputq, skb);
1281 			return true;
1282 		}
1283 		fallthrough;
1284 	case CONN_MANAGER:
1285 		skb_queue_tail(inputq, skb);
1286 		return true;
1287 	case GROUP_PROTOCOL:
1288 		skb_queue_tail(mc_inputq, skb);
1289 		return true;
1290 	case NAME_DISTRIBUTOR:
1291 		l->bc_rcvlink->state = LINK_ESTABLISHED;
1292 		skb_queue_tail(l->namedq, skb);
1293 		return true;
1294 	case MSG_BUNDLER:
1295 	case TUNNEL_PROTOCOL:
1296 	case MSG_FRAGMENTER:
1297 	case BCAST_PROTOCOL:
1298 		return false;
1299 #ifdef CONFIG_TIPC_CRYPTO
1300 	case MSG_CRYPTO:
1301 		tipc_crypto_msg_rcv(l->net, skb);
1302 		return true;
1303 #endif
1304 	default:
1305 		pr_warn("Dropping received illegal msg type\n");
1306 		kfree_skb(skb);
1307 		return true;
1308 	}
1309 }
1310 
1311 /* tipc_link_input - process packet that has passed link protocol check
1312  *
1313  * Consumes buffer
1314  */
1315 static int tipc_link_input(struct tipc_link *l, struct sk_buff *skb,
1316 			   struct sk_buff_head *inputq,
1317 			   struct sk_buff **reasm_skb)
1318 {
1319 	struct tipc_msg *hdr = buf_msg(skb);
1320 	struct sk_buff *iskb;
1321 	struct sk_buff_head tmpq;
1322 	int usr = msg_user(hdr);
1323 	int pos = 0;
1324 
1325 	if (usr == MSG_BUNDLER) {
1326 		skb_queue_head_init(&tmpq);
1327 		l->stats.recv_bundles++;
1328 		l->stats.recv_bundled += msg_msgcnt(hdr);
1329 		while (tipc_msg_extract(skb, &iskb, &pos))
1330 			tipc_data_input(l, iskb, &tmpq);
1331 		tipc_skb_queue_splice_tail(&tmpq, inputq);
1332 		return 0;
1333 	} else if (usr == MSG_FRAGMENTER) {
1334 		l->stats.recv_fragments++;
1335 		if (tipc_buf_append(reasm_skb, &skb)) {
1336 			l->stats.recv_fragmented++;
1337 			tipc_data_input(l, skb, inputq);
1338 		} else if (!*reasm_skb && !link_is_bc_rcvlink(l)) {
1339 			pr_warn_ratelimited("Unable to build fragment list\n");
1340 			return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1341 		}
1342 		return 0;
1343 	} else if (usr == BCAST_PROTOCOL) {
1344 		tipc_bcast_lock(l->net);
1345 		tipc_link_bc_init_rcv(l->bc_rcvlink, hdr);
1346 		tipc_bcast_unlock(l->net);
1347 	}
1348 
1349 	kfree_skb(skb);
1350 	return 0;
1351 }
1352 
1353 /* tipc_link_tnl_rcv() - receive TUNNEL_PROTOCOL message, drop or process the
1354  *			 inner message along with the ones in the old link's
1355  *			 deferdq
1356  * @l: tunnel link
1357  * @skb: TUNNEL_PROTOCOL message
1358  * @inputq: queue to put messages ready for delivery
1359  */
1360 static int tipc_link_tnl_rcv(struct tipc_link *l, struct sk_buff *skb,
1361 			     struct sk_buff_head *inputq)
1362 {
1363 	struct sk_buff **reasm_skb = &l->failover_reasm_skb;
1364 	struct sk_buff **reasm_tnlmsg = &l->reasm_tnlmsg;
1365 	struct sk_buff_head *fdefq = &l->failover_deferdq;
1366 	struct tipc_msg *hdr = buf_msg(skb);
1367 	struct sk_buff *iskb;
1368 	int ipos = 0;
1369 	int rc = 0;
1370 	u16 seqno;
1371 
1372 	if (msg_type(hdr) == SYNCH_MSG) {
1373 		kfree_skb(skb);
1374 		return 0;
1375 	}
1376 
1377 	/* Not a fragment? */
1378 	if (likely(!msg_nof_fragms(hdr))) {
1379 		if (unlikely(!tipc_msg_extract(skb, &iskb, &ipos))) {
1380 			pr_warn_ratelimited("Unable to extract msg, defq: %d\n",
1381 					    skb_queue_len(fdefq));
1382 			return 0;
1383 		}
1384 		kfree_skb(skb);
1385 	} else {
1386 		/* Set fragment type for buf_append */
1387 		if (msg_fragm_no(hdr) == 1)
1388 			msg_set_type(hdr, FIRST_FRAGMENT);
1389 		else if (msg_fragm_no(hdr) < msg_nof_fragms(hdr))
1390 			msg_set_type(hdr, FRAGMENT);
1391 		else
1392 			msg_set_type(hdr, LAST_FRAGMENT);
1393 
1394 		if (!tipc_buf_append(reasm_tnlmsg, &skb)) {
1395 			/* Successful but non-complete reassembly? */
1396 			if (*reasm_tnlmsg || link_is_bc_rcvlink(l))
1397 				return 0;
1398 			pr_warn_ratelimited("Unable to reassemble tunnel msg\n");
1399 			return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
1400 		}
1401 		iskb = skb;
1402 	}
1403 
1404 	do {
1405 		seqno = buf_seqno(iskb);
1406 		if (unlikely(less(seqno, l->drop_point))) {
1407 			kfree_skb(iskb);
1408 			continue;
1409 		}
1410 		if (unlikely(seqno != l->drop_point)) {
1411 			__tipc_skb_queue_sorted(fdefq, seqno, iskb);
1412 			continue;
1413 		}
1414 
1415 		l->drop_point++;
1416 		if (!tipc_data_input(l, iskb, inputq))
1417 			rc |= tipc_link_input(l, iskb, inputq, reasm_skb);
1418 		if (unlikely(rc))
1419 			break;
1420 	} while ((iskb = __tipc_skb_dequeue(fdefq, l->drop_point)));
1421 
1422 	return rc;
1423 }
1424 
1425 /**
1426  * tipc_get_gap_ack_blks - get Gap ACK blocks from PROTOCOL/STATE_MSG
1427  * @ga: returned pointer to the Gap ACK blocks if any
1428  * @l: the tipc link
1429  * @hdr: the PROTOCOL/STATE_MSG header
1430  * @uc: desired Gap ACK blocks type, i.e. unicast (= 1) or broadcast (= 0)
1431  *
1432  * Return: the total Gap ACK blocks size
1433  */
1434 u16 tipc_get_gap_ack_blks(struct tipc_gap_ack_blks **ga, struct tipc_link *l,
1435 			  struct tipc_msg *hdr, bool uc)
1436 {
1437 	struct tipc_gap_ack_blks *p;
1438 	u16 sz = 0;
1439 
1440 	/* Does peer support the Gap ACK blocks feature? */
1441 	if (l->peer_caps & TIPC_GAP_ACK_BLOCK) {
1442 		p = (struct tipc_gap_ack_blks *)msg_data(hdr);
1443 		sz = ntohs(p->len);
1444 		/* Sanity check */
1445 		if (sz == struct_size(p, gacks, p->ugack_cnt + p->bgack_cnt)) {
1446 			/* Good, check if the desired type exists */
1447 			if ((uc && p->ugack_cnt) || (!uc && p->bgack_cnt))
1448 				goto ok;
1449 		/* Backward compatible: peer might not support bc, but uc? */
1450 		} else if (uc && sz == struct_size(p, gacks, p->ugack_cnt)) {
1451 			if (p->ugack_cnt) {
1452 				p->bgack_cnt = 0;
1453 				goto ok;
1454 			}
1455 		}
1456 	}
1457 	/* Other cases: ignore! */
1458 	p = NULL;
1459 
1460 ok:
1461 	*ga = p;
1462 	return sz;
1463 }
1464 
1465 static u8 __tipc_build_gap_ack_blks(struct tipc_gap_ack_blks *ga,
1466 				    struct tipc_link *l, u8 start_index)
1467 {
1468 	struct tipc_gap_ack *gacks = &ga->gacks[start_index];
1469 	struct sk_buff *skb = skb_peek(&l->deferdq);
1470 	u16 expect, seqno = 0;
1471 	u8 n = 0;
1472 
1473 	if (!skb)
1474 		return 0;
1475 
1476 	expect = buf_seqno(skb);
1477 	skb_queue_walk(&l->deferdq, skb) {
1478 		seqno = buf_seqno(skb);
1479 		if (unlikely(more(seqno, expect))) {
1480 			gacks[n].ack = htons(expect - 1);
1481 			gacks[n].gap = htons(seqno - expect);
1482 			if (++n >= MAX_GAP_ACK_BLKS / 2) {
1483 				pr_info_ratelimited("Gacks on %s: %d, ql: %d!\n",
1484 						    l->name, n,
1485 						    skb_queue_len(&l->deferdq));
1486 				return n;
1487 			}
1488 		} else if (unlikely(less(seqno, expect))) {
1489 			pr_warn("Unexpected skb in deferdq!\n");
1490 			continue;
1491 		}
1492 		expect = seqno + 1;
1493 	}
1494 
1495 	/* last block */
1496 	gacks[n].ack = htons(seqno);
1497 	gacks[n].gap = 0;
1498 	n++;
1499 	return n;
1500 }
1501 
1502 /* tipc_build_gap_ack_blks - build Gap ACK blocks
1503  * @l: tipc unicast link
1504  * @hdr: the tipc message buffer to store the Gap ACK blocks after built
1505  *
1506  * The function builds Gap ACK blocks for both the unicast & broadcast receiver
1507  * links of a certain peer, the buffer after built has the network data format
1508  * as found at the struct tipc_gap_ack_blks definition.
1509  *
1510  * returns the actual allocated memory size
1511  */
1512 static u16 tipc_build_gap_ack_blks(struct tipc_link *l, struct tipc_msg *hdr)
1513 {
1514 	struct tipc_link *bcl = l->bc_rcvlink;
1515 	struct tipc_gap_ack_blks *ga;
1516 	u16 len;
1517 
1518 	ga = (struct tipc_gap_ack_blks *)msg_data(hdr);
1519 
1520 	/* Start with broadcast link first */
1521 	tipc_bcast_lock(bcl->net);
1522 	msg_set_bcast_ack(hdr, bcl->rcv_nxt - 1);
1523 	msg_set_bc_gap(hdr, link_bc_rcv_gap(bcl));
1524 	ga->bgack_cnt = __tipc_build_gap_ack_blks(ga, bcl, 0);
1525 	tipc_bcast_unlock(bcl->net);
1526 
1527 	/* Now for unicast link, but an explicit NACK only (???) */
1528 	ga->ugack_cnt = (msg_seq_gap(hdr)) ?
1529 			__tipc_build_gap_ack_blks(ga, l, ga->bgack_cnt) : 0;
1530 
1531 	/* Total len */
1532 	len = struct_size(ga, gacks, ga->bgack_cnt + ga->ugack_cnt);
1533 	ga->len = htons(len);
1534 	return len;
1535 }
1536 
1537 /* tipc_link_advance_transmq - advance TIPC link transmq queue by releasing
1538  *			       acked packets, also doing retransmissions if
1539  *			       gaps found
1540  * @l: tipc link with transmq queue to be advanced
1541  * @r: tipc link "receiver" i.e. in case of broadcast (= "l" if unicast)
1542  * @acked: seqno of last packet acked by peer without any gaps before
1543  * @gap: # of gap packets
1544  * @ga: buffer pointer to Gap ACK blocks from peer
1545  * @xmitq: queue for accumulating the retransmitted packets if any
1546  * @retransmitted: returned boolean value if a retransmission is really issued
1547  * @rc: returned code e.g. TIPC_LINK_DOWN_EVT if a repeated retransmit failures
1548  *      happens (- unlikely case)
1549  *
1550  * Return: the number of packets released from the link transmq
1551  */
1552 static int tipc_link_advance_transmq(struct tipc_link *l, struct tipc_link *r,
1553 				     u16 acked, u16 gap,
1554 				     struct tipc_gap_ack_blks *ga,
1555 				     struct sk_buff_head *xmitq,
1556 				     bool *retransmitted, int *rc)
1557 {
1558 	struct tipc_gap_ack_blks *last_ga = r->last_ga, *this_ga = NULL;
1559 	struct tipc_gap_ack *gacks = NULL;
1560 	struct sk_buff *skb, *_skb, *tmp;
1561 	struct tipc_msg *hdr;
1562 	u32 qlen = skb_queue_len(&l->transmq);
1563 	u16 nacked = acked, ngap = gap, gack_cnt = 0;
1564 	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
1565 	u16 ack = l->rcv_nxt - 1;
1566 	u16 seqno, n = 0;
1567 	u16 end = r->acked, start = end, offset = r->last_gap;
1568 	u16 si = (last_ga) ? last_ga->start_index : 0;
1569 	bool is_uc = !link_is_bc_sndlink(l);
1570 	bool bc_has_acked = false;
1571 
1572 	trace_tipc_link_retrans(r, acked + 1, acked + gap, &l->transmq);
1573 
1574 	/* Determine Gap ACK blocks if any for the particular link */
1575 	if (ga && is_uc) {
1576 		/* Get the Gap ACKs, uc part */
1577 		gack_cnt = ga->ugack_cnt;
1578 		gacks = &ga->gacks[ga->bgack_cnt];
1579 	} else if (ga) {
1580 		/* Copy the Gap ACKs, bc part, for later renewal if needed */
1581 		this_ga = kmemdup(ga, struct_size(ga, gacks, ga->bgack_cnt),
1582 				  GFP_ATOMIC);
1583 		if (likely(this_ga)) {
1584 			this_ga->start_index = 0;
1585 			/* Start with the bc Gap ACKs */
1586 			gack_cnt = this_ga->bgack_cnt;
1587 			gacks = &this_ga->gacks[0];
1588 		} else {
1589 			/* Hmm, we can get in trouble..., simply ignore it */
1590 			pr_warn_ratelimited("Ignoring bc Gap ACKs, no memory\n");
1591 		}
1592 	}
1593 
1594 	/* Advance the link transmq */
1595 	skb_queue_walk_safe(&l->transmq, skb, tmp) {
1596 		seqno = buf_seqno(skb);
1597 
1598 next_gap_ack:
1599 		if (less_eq(seqno, nacked)) {
1600 			if (is_uc)
1601 				goto release;
1602 			/* Skip packets peer has already acked */
1603 			if (!more(seqno, r->acked))
1604 				continue;
1605 			/* Get the next of last Gap ACK blocks */
1606 			while (more(seqno, end)) {
1607 				if (!last_ga || si >= last_ga->bgack_cnt)
1608 					break;
1609 				start = end + offset + 1;
1610 				end = ntohs(last_ga->gacks[si].ack);
1611 				offset = ntohs(last_ga->gacks[si].gap);
1612 				si++;
1613 				WARN_ONCE(more(start, end) ||
1614 					  (!offset &&
1615 					   si < last_ga->bgack_cnt) ||
1616 					  si > MAX_GAP_ACK_BLKS,
1617 					  "Corrupted Gap ACK: %d %d %d %d %d\n",
1618 					  start, end, offset, si,
1619 					  last_ga->bgack_cnt);
1620 			}
1621 			/* Check against the last Gap ACK block */
1622 			if (in_range(seqno, start, end))
1623 				continue;
1624 			/* Update/release the packet peer is acking */
1625 			bc_has_acked = true;
1626 			if (--TIPC_SKB_CB(skb)->ackers)
1627 				continue;
1628 release:
1629 			/* release skb */
1630 			__skb_unlink(skb, &l->transmq);
1631 			kfree_skb(skb);
1632 		} else if (less_eq(seqno, nacked + ngap)) {
1633 			/* First gap: check if repeated retrans failures? */
1634 			if (unlikely(seqno == acked + 1 &&
1635 				     link_retransmit_failure(l, r, rc))) {
1636 				/* Ignore this bc Gap ACKs if any */
1637 				kfree(this_ga);
1638 				this_ga = NULL;
1639 				break;
1640 			}
1641 			/* retransmit skb if unrestricted*/
1642 			if (time_before(jiffies, TIPC_SKB_CB(skb)->nxt_retr))
1643 				continue;
1644 			tipc_link_set_skb_retransmit_time(skb, l);
1645 			_skb = pskb_copy(skb, GFP_ATOMIC);
1646 			if (!_skb)
1647 				continue;
1648 			hdr = buf_msg(_skb);
1649 			msg_set_ack(hdr, ack);
1650 			msg_set_bcast_ack(hdr, bc_ack);
1651 			_skb->priority = TC_PRIO_CONTROL;
1652 			__skb_queue_tail(xmitq, _skb);
1653 			l->stats.retransmitted++;
1654 			if (!is_uc)
1655 				r->stats.retransmitted++;
1656 			*retransmitted = true;
1657 			/* Increase actual retrans counter & mark first time */
1658 			if (!TIPC_SKB_CB(skb)->retr_cnt++)
1659 				TIPC_SKB_CB(skb)->retr_stamp = jiffies;
1660 		} else {
1661 			/* retry with Gap ACK blocks if any */
1662 			if (n >= gack_cnt)
1663 				break;
1664 			nacked = ntohs(gacks[n].ack);
1665 			ngap = ntohs(gacks[n].gap);
1666 			n++;
1667 			goto next_gap_ack;
1668 		}
1669 	}
1670 
1671 	/* Renew last Gap ACK blocks for bc if needed */
1672 	if (bc_has_acked) {
1673 		if (this_ga) {
1674 			kfree(last_ga);
1675 			r->last_ga = this_ga;
1676 			r->last_gap = gap;
1677 		} else if (last_ga) {
1678 			if (less(acked, start)) {
1679 				si--;
1680 				offset = start - acked - 1;
1681 			} else if (less(acked, end)) {
1682 				acked = end;
1683 			}
1684 			if (si < last_ga->bgack_cnt) {
1685 				last_ga->start_index = si;
1686 				r->last_gap = offset;
1687 			} else {
1688 				kfree(last_ga);
1689 				r->last_ga = NULL;
1690 				r->last_gap = 0;
1691 			}
1692 		} else {
1693 			r->last_gap = 0;
1694 		}
1695 		r->acked = acked;
1696 	} else {
1697 		kfree(this_ga);
1698 	}
1699 
1700 	return qlen - skb_queue_len(&l->transmq);
1701 }
1702 
1703 /* tipc_link_build_state_msg: prepare link state message for transmission
1704  *
1705  * Note that sending of broadcast ack is coordinated among nodes, to reduce
1706  * risk of ack storms towards the sender
1707  */
1708 int tipc_link_build_state_msg(struct tipc_link *l, struct sk_buff_head *xmitq)
1709 {
1710 	if (!l)
1711 		return 0;
1712 
1713 	/* Broadcast ACK must be sent via a unicast link => defer to caller */
1714 	if (link_is_bc_rcvlink(l)) {
1715 		if (((l->rcv_nxt ^ tipc_own_addr(l->net)) & 0xf) != 0xf)
1716 			return 0;
1717 		l->rcv_unacked = 0;
1718 
1719 		/* Use snd_nxt to store peer's snd_nxt in broadcast rcv link */
1720 		l->snd_nxt = l->rcv_nxt;
1721 		return TIPC_LINK_SND_STATE;
1722 	}
1723 	/* Unicast ACK */
1724 	l->rcv_unacked = 0;
1725 	l->stats.sent_acks++;
1726 	tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, 0, 0, xmitq);
1727 	return 0;
1728 }
1729 
1730 /* tipc_link_build_reset_msg: prepare link RESET or ACTIVATE message
1731  */
1732 void tipc_link_build_reset_msg(struct tipc_link *l, struct sk_buff_head *xmitq)
1733 {
1734 	int mtyp = RESET_MSG;
1735 	struct sk_buff *skb;
1736 
1737 	if (l->state == LINK_ESTABLISHING)
1738 		mtyp = ACTIVATE_MSG;
1739 
1740 	tipc_link_build_proto_msg(l, mtyp, 0, 0, 0, 0, 0, xmitq);
1741 
1742 	/* Inform peer that this endpoint is going down if applicable */
1743 	skb = skb_peek_tail(xmitq);
1744 	if (skb && (l->state == LINK_RESET))
1745 		msg_set_peer_stopping(buf_msg(skb), 1);
1746 }
1747 
1748 /* tipc_link_build_nack_msg: prepare link nack message for transmission
1749  * Note that sending of broadcast NACK is coordinated among nodes, to
1750  * reduce the risk of NACK storms towards the sender
1751  */
1752 static int tipc_link_build_nack_msg(struct tipc_link *l,
1753 				    struct sk_buff_head *xmitq)
1754 {
1755 	u32 def_cnt = ++l->stats.deferred_recv;
1756 	struct sk_buff_head *dfq = &l->deferdq;
1757 	u32 defq_len = skb_queue_len(dfq);
1758 	int match1, match2;
1759 
1760 	if (link_is_bc_rcvlink(l)) {
1761 		match1 = def_cnt & 0xf;
1762 		match2 = tipc_own_addr(l->net) & 0xf;
1763 		if (match1 == match2)
1764 			return TIPC_LINK_SND_STATE;
1765 		return 0;
1766 	}
1767 
1768 	if (defq_len >= 3 && !((defq_len - 3) % 16)) {
1769 		u16 rcvgap = buf_seqno(skb_peek(dfq)) - l->rcv_nxt;
1770 
1771 		tipc_link_build_proto_msg(l, STATE_MSG, 0, 0,
1772 					  rcvgap, 0, 0, xmitq);
1773 	}
1774 	return 0;
1775 }
1776 
1777 /* tipc_link_rcv - process TIPC packets/messages arriving from off-node
1778  * @l: the link that should handle the message
1779  * @skb: TIPC packet
1780  * @xmitq: queue to place packets to be sent after this call
1781  */
1782 int tipc_link_rcv(struct tipc_link *l, struct sk_buff *skb,
1783 		  struct sk_buff_head *xmitq)
1784 {
1785 	struct sk_buff_head *defq = &l->deferdq;
1786 	struct tipc_msg *hdr = buf_msg(skb);
1787 	u16 seqno, rcv_nxt, win_lim;
1788 	int released = 0;
1789 	int rc = 0;
1790 
1791 	/* Verify and update link state */
1792 	if (unlikely(msg_user(hdr) == LINK_PROTOCOL))
1793 		return tipc_link_proto_rcv(l, skb, xmitq);
1794 
1795 	/* Don't send probe at next timeout expiration */
1796 	l->silent_intv_cnt = 0;
1797 
1798 	do {
1799 		hdr = buf_msg(skb);
1800 		seqno = msg_seqno(hdr);
1801 		rcv_nxt = l->rcv_nxt;
1802 		win_lim = rcv_nxt + TIPC_MAX_LINK_WIN;
1803 
1804 		if (unlikely(!link_is_up(l))) {
1805 			if (l->state == LINK_ESTABLISHING)
1806 				rc = TIPC_LINK_UP_EVT;
1807 			kfree_skb(skb);
1808 			break;
1809 		}
1810 
1811 		/* Drop if outside receive window */
1812 		if (unlikely(less(seqno, rcv_nxt) || more(seqno, win_lim))) {
1813 			l->stats.duplicates++;
1814 			kfree_skb(skb);
1815 			break;
1816 		}
1817 		released += tipc_link_advance_transmq(l, l, msg_ack(hdr), 0,
1818 						      NULL, NULL, NULL, NULL);
1819 
1820 		/* Defer delivery if sequence gap */
1821 		if (unlikely(seqno != rcv_nxt)) {
1822 			if (!__tipc_skb_queue_sorted(defq, seqno, skb))
1823 				l->stats.duplicates++;
1824 			rc |= tipc_link_build_nack_msg(l, xmitq);
1825 			break;
1826 		}
1827 
1828 		/* Deliver packet */
1829 		l->rcv_nxt++;
1830 		l->stats.recv_pkts++;
1831 
1832 		if (unlikely(msg_user(hdr) == TUNNEL_PROTOCOL))
1833 			rc |= tipc_link_tnl_rcv(l, skb, l->inputq);
1834 		else if (!tipc_data_input(l, skb, l->inputq))
1835 			rc |= tipc_link_input(l, skb, l->inputq, &l->reasm_buf);
1836 		if (unlikely(++l->rcv_unacked >= TIPC_MIN_LINK_WIN))
1837 			rc |= tipc_link_build_state_msg(l, xmitq);
1838 		if (unlikely(rc & ~TIPC_LINK_SND_STATE))
1839 			break;
1840 	} while ((skb = __tipc_skb_dequeue(defq, l->rcv_nxt)));
1841 
1842 	/* Forward queues and wake up waiting users */
1843 	if (released) {
1844 		tipc_link_update_cwin(l, released, 0);
1845 		tipc_link_advance_backlog(l, xmitq);
1846 		if (unlikely(!skb_queue_empty(&l->wakeupq)))
1847 			link_prepare_wakeup(l);
1848 	}
1849 	return rc;
1850 }
1851 
1852 static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
1853 				      bool probe_reply, u16 rcvgap,
1854 				      int tolerance, int priority,
1855 				      struct sk_buff_head *xmitq)
1856 {
1857 	struct tipc_mon_state *mstate = &l->mon_state;
1858 	struct sk_buff_head *dfq = &l->deferdq;
1859 	struct tipc_link *bcl = l->bc_rcvlink;
1860 	struct tipc_msg *hdr;
1861 	struct sk_buff *skb;
1862 	bool node_up = link_is_up(bcl);
1863 	u16 glen = 0, bc_rcvgap = 0;
1864 	int dlen = 0;
1865 	void *data;
1866 
1867 	/* Don't send protocol message during reset or link failover */
1868 	if (tipc_link_is_blocked(l))
1869 		return;
1870 
1871 	if (!tipc_link_is_up(l) && (mtyp == STATE_MSG))
1872 		return;
1873 
1874 	if ((probe || probe_reply) && !skb_queue_empty(dfq))
1875 		rcvgap = buf_seqno(skb_peek(dfq)) - l->rcv_nxt;
1876 
1877 	skb = tipc_msg_create(LINK_PROTOCOL, mtyp, INT_H_SIZE,
1878 			      tipc_max_domain_size + MAX_GAP_ACK_BLKS_SZ,
1879 			      l->addr, tipc_own_addr(l->net), 0, 0, 0);
1880 	if (!skb)
1881 		return;
1882 
1883 	hdr = buf_msg(skb);
1884 	data = msg_data(hdr);
1885 	msg_set_session(hdr, l->session);
1886 	msg_set_bearer_id(hdr, l->bearer_id);
1887 	msg_set_net_plane(hdr, l->net_plane);
1888 	msg_set_next_sent(hdr, l->snd_nxt);
1889 	msg_set_ack(hdr, l->rcv_nxt - 1);
1890 	msg_set_bcast_ack(hdr, bcl->rcv_nxt - 1);
1891 	msg_set_bc_ack_invalid(hdr, !node_up);
1892 	msg_set_last_bcast(hdr, l->bc_sndlink->snd_nxt - 1);
1893 	msg_set_link_tolerance(hdr, tolerance);
1894 	msg_set_linkprio(hdr, priority);
1895 	msg_set_redundant_link(hdr, node_up);
1896 	msg_set_seq_gap(hdr, 0);
1897 	msg_set_seqno(hdr, l->snd_nxt + U16_MAX / 2);
1898 
1899 	if (mtyp == STATE_MSG) {
1900 		if (l->peer_caps & TIPC_LINK_PROTO_SEQNO)
1901 			msg_set_seqno(hdr, l->snd_nxt_state++);
1902 		msg_set_seq_gap(hdr, rcvgap);
1903 		bc_rcvgap = link_bc_rcv_gap(bcl);
1904 		msg_set_bc_gap(hdr, bc_rcvgap);
1905 		msg_set_probe(hdr, probe);
1906 		msg_set_is_keepalive(hdr, probe || probe_reply);
1907 		if (l->peer_caps & TIPC_GAP_ACK_BLOCK)
1908 			glen = tipc_build_gap_ack_blks(l, hdr);
1909 		tipc_mon_prep(l->net, data + glen, &dlen, mstate, l->bearer_id);
1910 		msg_set_size(hdr, INT_H_SIZE + glen + dlen);
1911 		skb_trim(skb, INT_H_SIZE + glen + dlen);
1912 		l->stats.sent_states++;
1913 		l->rcv_unacked = 0;
1914 	} else {
1915 		/* RESET_MSG or ACTIVATE_MSG */
1916 		if (mtyp == ACTIVATE_MSG) {
1917 			msg_set_dest_session_valid(hdr, 1);
1918 			msg_set_dest_session(hdr, l->peer_session);
1919 		}
1920 		msg_set_max_pkt(hdr, l->advertised_mtu);
1921 		strcpy(data, l->if_name);
1922 		msg_set_size(hdr, INT_H_SIZE + TIPC_MAX_IF_NAME);
1923 		skb_trim(skb, INT_H_SIZE + TIPC_MAX_IF_NAME);
1924 	}
1925 	if (probe)
1926 		l->stats.sent_probes++;
1927 	if (rcvgap)
1928 		l->stats.sent_nacks++;
1929 	if (bc_rcvgap)
1930 		bcl->stats.sent_nacks++;
1931 	skb->priority = TC_PRIO_CONTROL;
1932 	__skb_queue_tail(xmitq, skb);
1933 	trace_tipc_proto_build(skb, false, l->name);
1934 }
1935 
1936 void tipc_link_create_dummy_tnl_msg(struct tipc_link *l,
1937 				    struct sk_buff_head *xmitq)
1938 {
1939 	u32 onode = tipc_own_addr(l->net);
1940 	struct tipc_msg *hdr, *ihdr;
1941 	struct sk_buff_head tnlq;
1942 	struct sk_buff *skb;
1943 	u32 dnode = l->addr;
1944 
1945 	__skb_queue_head_init(&tnlq);
1946 	skb = tipc_msg_create(TUNNEL_PROTOCOL, FAILOVER_MSG,
1947 			      INT_H_SIZE, BASIC_H_SIZE,
1948 			      dnode, onode, 0, 0, 0);
1949 	if (!skb) {
1950 		pr_warn("%sunable to create tunnel packet\n", link_co_err);
1951 		return;
1952 	}
1953 
1954 	hdr = buf_msg(skb);
1955 	msg_set_msgcnt(hdr, 1);
1956 	msg_set_bearer_id(hdr, l->peer_bearer_id);
1957 
1958 	ihdr = (struct tipc_msg *)msg_data(hdr);
1959 	tipc_msg_init(onode, ihdr, TIPC_LOW_IMPORTANCE, TIPC_DIRECT_MSG,
1960 		      BASIC_H_SIZE, dnode);
1961 	msg_set_errcode(ihdr, TIPC_ERR_NO_PORT);
1962 	__skb_queue_tail(&tnlq, skb);
1963 	tipc_link_xmit(l, &tnlq, xmitq);
1964 }
1965 
1966 /* tipc_link_tnl_prepare(): prepare and return a list of tunnel packets
1967  * with contents of the link's transmit and backlog queues.
1968  */
1969 void tipc_link_tnl_prepare(struct tipc_link *l, struct tipc_link *tnl,
1970 			   int mtyp, struct sk_buff_head *xmitq)
1971 {
1972 	struct sk_buff_head *fdefq = &tnl->failover_deferdq;
1973 	struct sk_buff *skb, *tnlskb;
1974 	struct tipc_msg *hdr, tnlhdr;
1975 	struct sk_buff_head *queue = &l->transmq;
1976 	struct sk_buff_head tmpxq, tnlq, frags;
1977 	u16 pktlen, pktcnt, seqno = l->snd_nxt;
1978 	bool pktcnt_need_update = false;
1979 	u16 syncpt;
1980 	int rc;
1981 
1982 	if (!tnl)
1983 		return;
1984 
1985 	__skb_queue_head_init(&tnlq);
1986 	/* Link Synching:
1987 	 * From now on, send only one single ("dummy") SYNCH message
1988 	 * to peer. The SYNCH message does not contain any data, just
1989 	 * a header conveying the synch point to the peer.
1990 	 */
1991 	if (mtyp == SYNCH_MSG && (tnl->peer_caps & TIPC_TUNNEL_ENHANCED)) {
1992 		tnlskb = tipc_msg_create(TUNNEL_PROTOCOL, SYNCH_MSG,
1993 					 INT_H_SIZE, 0, l->addr,
1994 					 tipc_own_addr(l->net),
1995 					 0, 0, 0);
1996 		if (!tnlskb) {
1997 			pr_warn("%sunable to create dummy SYNCH_MSG\n",
1998 				link_co_err);
1999 			return;
2000 		}
2001 
2002 		hdr = buf_msg(tnlskb);
2003 		syncpt = l->snd_nxt + skb_queue_len(&l->backlogq) - 1;
2004 		msg_set_syncpt(hdr, syncpt);
2005 		msg_set_bearer_id(hdr, l->peer_bearer_id);
2006 		__skb_queue_tail(&tnlq, tnlskb);
2007 		tipc_link_xmit(tnl, &tnlq, xmitq);
2008 		return;
2009 	}
2010 
2011 	__skb_queue_head_init(&tmpxq);
2012 	__skb_queue_head_init(&frags);
2013 	/* At least one packet required for safe algorithm => add dummy */
2014 	skb = tipc_msg_create(TIPC_LOW_IMPORTANCE, TIPC_DIRECT_MSG,
2015 			      BASIC_H_SIZE, 0, l->addr, tipc_own_addr(l->net),
2016 			      0, 0, TIPC_ERR_NO_PORT);
2017 	if (!skb) {
2018 		pr_warn("%sunable to create tunnel packet\n", link_co_err);
2019 		return;
2020 	}
2021 	__skb_queue_tail(&tnlq, skb);
2022 	tipc_link_xmit(l, &tnlq, &tmpxq);
2023 	__skb_queue_purge(&tmpxq);
2024 
2025 	/* Initialize reusable tunnel packet header */
2026 	tipc_msg_init(tipc_own_addr(l->net), &tnlhdr, TUNNEL_PROTOCOL,
2027 		      mtyp, INT_H_SIZE, l->addr);
2028 	if (mtyp == SYNCH_MSG)
2029 		pktcnt = l->snd_nxt - buf_seqno(skb_peek(&l->transmq));
2030 	else
2031 		pktcnt = skb_queue_len(&l->transmq);
2032 	pktcnt += skb_queue_len(&l->backlogq);
2033 	msg_set_msgcnt(&tnlhdr, pktcnt);
2034 	msg_set_bearer_id(&tnlhdr, l->peer_bearer_id);
2035 tnl:
2036 	/* Wrap each packet into a tunnel packet */
2037 	skb_queue_walk(queue, skb) {
2038 		hdr = buf_msg(skb);
2039 		if (queue == &l->backlogq)
2040 			msg_set_seqno(hdr, seqno++);
2041 		pktlen = msg_size(hdr);
2042 
2043 		/* Tunnel link MTU is not large enough? This could be
2044 		 * due to:
2045 		 * 1) Link MTU has just changed or set differently;
2046 		 * 2) Or FAILOVER on the top of a SYNCH message
2047 		 *
2048 		 * The 2nd case should not happen if peer supports
2049 		 * TIPC_TUNNEL_ENHANCED
2050 		 */
2051 		if (pktlen > tnl->mtu - INT_H_SIZE) {
2052 			if (mtyp == FAILOVER_MSG &&
2053 			    (tnl->peer_caps & TIPC_TUNNEL_ENHANCED)) {
2054 				rc = tipc_msg_fragment(skb, &tnlhdr, tnl->mtu,
2055 						       &frags);
2056 				if (rc) {
2057 					pr_warn("%sunable to frag msg: rc %d\n",
2058 						link_co_err, rc);
2059 					return;
2060 				}
2061 				pktcnt += skb_queue_len(&frags) - 1;
2062 				pktcnt_need_update = true;
2063 				skb_queue_splice_tail_init(&frags, &tnlq);
2064 				continue;
2065 			}
2066 			/* Unluckily, peer doesn't have TIPC_TUNNEL_ENHANCED
2067 			 * => Just warn it and return!
2068 			 */
2069 			pr_warn_ratelimited("%stoo large msg <%d, %d>: %d!\n",
2070 					    link_co_err, msg_user(hdr),
2071 					    msg_type(hdr), msg_size(hdr));
2072 			return;
2073 		}
2074 
2075 		msg_set_size(&tnlhdr, pktlen + INT_H_SIZE);
2076 		tnlskb = tipc_buf_acquire(pktlen + INT_H_SIZE, GFP_ATOMIC);
2077 		if (!tnlskb) {
2078 			pr_warn("%sunable to send packet\n", link_co_err);
2079 			return;
2080 		}
2081 		skb_copy_to_linear_data(tnlskb, &tnlhdr, INT_H_SIZE);
2082 		skb_copy_to_linear_data_offset(tnlskb, INT_H_SIZE, hdr, pktlen);
2083 		__skb_queue_tail(&tnlq, tnlskb);
2084 	}
2085 	if (queue != &l->backlogq) {
2086 		queue = &l->backlogq;
2087 		goto tnl;
2088 	}
2089 
2090 	if (pktcnt_need_update)
2091 		skb_queue_walk(&tnlq, skb) {
2092 			hdr = buf_msg(skb);
2093 			msg_set_msgcnt(hdr, pktcnt);
2094 		}
2095 
2096 	tipc_link_xmit(tnl, &tnlq, xmitq);
2097 
2098 	if (mtyp == FAILOVER_MSG) {
2099 		tnl->drop_point = l->rcv_nxt;
2100 		tnl->failover_reasm_skb = l->reasm_buf;
2101 		l->reasm_buf = NULL;
2102 
2103 		/* Failover the link's deferdq */
2104 		if (unlikely(!skb_queue_empty(fdefq))) {
2105 			pr_warn("Link failover deferdq not empty: %d!\n",
2106 				skb_queue_len(fdefq));
2107 			__skb_queue_purge(fdefq);
2108 		}
2109 		skb_queue_splice_init(&l->deferdq, fdefq);
2110 	}
2111 }
2112 
2113 /**
2114  * tipc_link_failover_prepare() - prepare tnl for link failover
2115  *
2116  * This is a special version of the precursor - tipc_link_tnl_prepare(),
2117  * see the tipc_node_link_failover() for details
2118  *
2119  * @l: failover link
2120  * @tnl: tunnel link
2121  * @xmitq: queue for messages to be xmited
2122  */
2123 void tipc_link_failover_prepare(struct tipc_link *l, struct tipc_link *tnl,
2124 				struct sk_buff_head *xmitq)
2125 {
2126 	struct sk_buff_head *fdefq = &tnl->failover_deferdq;
2127 
2128 	tipc_link_create_dummy_tnl_msg(tnl, xmitq);
2129 
2130 	/* This failover link endpoint was never established before,
2131 	 * so it has not received anything from peer.
2132 	 * Otherwise, it must be a normal failover situation or the
2133 	 * node has entered SELF_DOWN_PEER_LEAVING and both peer nodes
2134 	 * would have to start over from scratch instead.
2135 	 */
2136 	tnl->drop_point = 1;
2137 	tnl->failover_reasm_skb = NULL;
2138 
2139 	/* Initiate the link's failover deferdq */
2140 	if (unlikely(!skb_queue_empty(fdefq))) {
2141 		pr_warn("Link failover deferdq not empty: %d!\n",
2142 			skb_queue_len(fdefq));
2143 		__skb_queue_purge(fdefq);
2144 	}
2145 }
2146 
2147 /* tipc_link_validate_msg(): validate message against current link state
2148  * Returns true if message should be accepted, otherwise false
2149  */
2150 bool tipc_link_validate_msg(struct tipc_link *l, struct tipc_msg *hdr)
2151 {
2152 	u16 curr_session = l->peer_session;
2153 	u16 session = msg_session(hdr);
2154 	int mtyp = msg_type(hdr);
2155 
2156 	if (msg_user(hdr) != LINK_PROTOCOL)
2157 		return true;
2158 
2159 	switch (mtyp) {
2160 	case RESET_MSG:
2161 		if (!l->in_session)
2162 			return true;
2163 		/* Accept only RESET with new session number */
2164 		return more(session, curr_session);
2165 	case ACTIVATE_MSG:
2166 		if (!l->in_session)
2167 			return true;
2168 		/* Accept only ACTIVATE with new or current session number */
2169 		return !less(session, curr_session);
2170 	case STATE_MSG:
2171 		/* Accept only STATE with current session number */
2172 		if (!l->in_session)
2173 			return false;
2174 		if (session != curr_session)
2175 			return false;
2176 		/* Extra sanity check */
2177 		if (!link_is_up(l) && msg_ack(hdr))
2178 			return false;
2179 		if (!(l->peer_caps & TIPC_LINK_PROTO_SEQNO))
2180 			return true;
2181 		/* Accept only STATE with new sequence number */
2182 		return !less(msg_seqno(hdr), l->rcv_nxt_state);
2183 	default:
2184 		return false;
2185 	}
2186 }
2187 
2188 /* tipc_link_proto_rcv(): receive link level protocol message :
2189  * Note that network plane id propagates through the network, and may
2190  * change at any time. The node with lowest numerical id determines
2191  * network plane
2192  */
2193 static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
2194 			       struct sk_buff_head *xmitq)
2195 {
2196 	struct tipc_msg *hdr = buf_msg(skb);
2197 	struct tipc_gap_ack_blks *ga = NULL;
2198 	bool reply = msg_probe(hdr), retransmitted = false;
2199 	u16 dlen = msg_data_sz(hdr), glen = 0;
2200 	u16 peers_snd_nxt =  msg_next_sent(hdr);
2201 	u16 peers_tol = msg_link_tolerance(hdr);
2202 	u16 peers_prio = msg_linkprio(hdr);
2203 	u16 gap = msg_seq_gap(hdr);
2204 	u16 ack = msg_ack(hdr);
2205 	u16 rcv_nxt = l->rcv_nxt;
2206 	u16 rcvgap = 0;
2207 	int mtyp = msg_type(hdr);
2208 	int rc = 0, released;
2209 	char *if_name;
2210 	void *data;
2211 
2212 	trace_tipc_proto_rcv(skb, false, l->name);
2213 	if (tipc_link_is_blocked(l) || !xmitq)
2214 		goto exit;
2215 
2216 	if (tipc_own_addr(l->net) > msg_prevnode(hdr))
2217 		l->net_plane = msg_net_plane(hdr);
2218 
2219 	skb_linearize(skb);
2220 	hdr = buf_msg(skb);
2221 	data = msg_data(hdr);
2222 
2223 	if (!tipc_link_validate_msg(l, hdr)) {
2224 		trace_tipc_skb_dump(skb, false, "PROTO invalid (1)!");
2225 		trace_tipc_link_dump(l, TIPC_DUMP_NONE, "PROTO invalid (1)!");
2226 		goto exit;
2227 	}
2228 
2229 	switch (mtyp) {
2230 	case RESET_MSG:
2231 	case ACTIVATE_MSG:
2232 		/* Complete own link name with peer's interface name */
2233 		if_name =  strrchr(l->name, ':') + 1;
2234 		if (sizeof(l->name) - (if_name - l->name) <= TIPC_MAX_IF_NAME)
2235 			break;
2236 		if (msg_data_sz(hdr) < TIPC_MAX_IF_NAME)
2237 			break;
2238 		strncpy(if_name, data, TIPC_MAX_IF_NAME);
2239 
2240 		/* Update own tolerance if peer indicates a non-zero value */
2241 		if (in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL)) {
2242 			l->tolerance = peers_tol;
2243 			l->bc_rcvlink->tolerance = peers_tol;
2244 		}
2245 		/* Update own priority if peer's priority is higher */
2246 		if (in_range(peers_prio, l->priority + 1, TIPC_MAX_LINK_PRI))
2247 			l->priority = peers_prio;
2248 
2249 		/* If peer is going down we want full re-establish cycle */
2250 		if (msg_peer_stopping(hdr)) {
2251 			rc = tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
2252 			break;
2253 		}
2254 
2255 		/* If this endpoint was re-created while peer was ESTABLISHING
2256 		 * it doesn't know current session number. Force re-synch.
2257 		 */
2258 		if (mtyp == ACTIVATE_MSG && msg_dest_session_valid(hdr) &&
2259 		    l->session != msg_dest_session(hdr)) {
2260 			if (less(l->session, msg_dest_session(hdr)))
2261 				l->session = msg_dest_session(hdr) + 1;
2262 			break;
2263 		}
2264 
2265 		/* ACTIVATE_MSG serves as PEER_RESET if link is already down */
2266 		if (mtyp == RESET_MSG || !link_is_up(l))
2267 			rc = tipc_link_fsm_evt(l, LINK_PEER_RESET_EVT);
2268 
2269 		/* ACTIVATE_MSG takes up link if it was already locally reset */
2270 		if (mtyp == ACTIVATE_MSG && l->state == LINK_ESTABLISHING)
2271 			rc = TIPC_LINK_UP_EVT;
2272 
2273 		l->peer_session = msg_session(hdr);
2274 		l->in_session = true;
2275 		l->peer_bearer_id = msg_bearer_id(hdr);
2276 		if (l->mtu > msg_max_pkt(hdr))
2277 			l->mtu = msg_max_pkt(hdr);
2278 		break;
2279 
2280 	case STATE_MSG:
2281 		l->rcv_nxt_state = msg_seqno(hdr) + 1;
2282 
2283 		/* Update own tolerance if peer indicates a non-zero value */
2284 		if (in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL)) {
2285 			l->tolerance = peers_tol;
2286 			l->bc_rcvlink->tolerance = peers_tol;
2287 		}
2288 		/* Update own prio if peer indicates a different value */
2289 		if ((peers_prio != l->priority) &&
2290 		    in_range(peers_prio, 1, TIPC_MAX_LINK_PRI)) {
2291 			l->priority = peers_prio;
2292 			rc = tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
2293 		}
2294 
2295 		l->silent_intv_cnt = 0;
2296 		l->stats.recv_states++;
2297 		if (msg_probe(hdr))
2298 			l->stats.recv_probes++;
2299 
2300 		if (!link_is_up(l)) {
2301 			if (l->state == LINK_ESTABLISHING)
2302 				rc = TIPC_LINK_UP_EVT;
2303 			break;
2304 		}
2305 
2306 		/* Receive Gap ACK blocks from peer if any */
2307 		glen = tipc_get_gap_ack_blks(&ga, l, hdr, true);
2308 
2309 		tipc_mon_rcv(l->net, data + glen, dlen - glen, l->addr,
2310 			     &l->mon_state, l->bearer_id);
2311 
2312 		/* Send NACK if peer has sent pkts we haven't received yet */
2313 		if ((reply || msg_is_keepalive(hdr)) &&
2314 		    more(peers_snd_nxt, rcv_nxt) &&
2315 		    !tipc_link_is_synching(l) &&
2316 		    skb_queue_empty(&l->deferdq))
2317 			rcvgap = peers_snd_nxt - l->rcv_nxt;
2318 		if (rcvgap || reply)
2319 			tipc_link_build_proto_msg(l, STATE_MSG, 0, reply,
2320 						  rcvgap, 0, 0, xmitq);
2321 
2322 		released = tipc_link_advance_transmq(l, l, ack, gap, ga, xmitq,
2323 						     &retransmitted, &rc);
2324 		if (gap)
2325 			l->stats.recv_nacks++;
2326 		if (released || retransmitted)
2327 			tipc_link_update_cwin(l, released, retransmitted);
2328 		if (released)
2329 			tipc_link_advance_backlog(l, xmitq);
2330 		if (unlikely(!skb_queue_empty(&l->wakeupq)))
2331 			link_prepare_wakeup(l);
2332 	}
2333 exit:
2334 	kfree_skb(skb);
2335 	return rc;
2336 }
2337 
2338 /* tipc_link_build_bc_proto_msg() - create broadcast protocol message
2339  */
2340 static bool tipc_link_build_bc_proto_msg(struct tipc_link *l, bool bcast,
2341 					 u16 peers_snd_nxt,
2342 					 struct sk_buff_head *xmitq)
2343 {
2344 	struct sk_buff *skb;
2345 	struct tipc_msg *hdr;
2346 	struct sk_buff *dfrd_skb = skb_peek(&l->deferdq);
2347 	u16 ack = l->rcv_nxt - 1;
2348 	u16 gap_to = peers_snd_nxt - 1;
2349 
2350 	skb = tipc_msg_create(BCAST_PROTOCOL, STATE_MSG, INT_H_SIZE,
2351 			      0, l->addr, tipc_own_addr(l->net), 0, 0, 0);
2352 	if (!skb)
2353 		return false;
2354 	hdr = buf_msg(skb);
2355 	msg_set_last_bcast(hdr, l->bc_sndlink->snd_nxt - 1);
2356 	msg_set_bcast_ack(hdr, ack);
2357 	msg_set_bcgap_after(hdr, ack);
2358 	if (dfrd_skb)
2359 		gap_to = buf_seqno(dfrd_skb) - 1;
2360 	msg_set_bcgap_to(hdr, gap_to);
2361 	msg_set_non_seq(hdr, bcast);
2362 	__skb_queue_tail(xmitq, skb);
2363 	return true;
2364 }
2365 
2366 /* tipc_link_build_bc_init_msg() - synchronize broadcast link endpoints.
2367  *
2368  * Give a newly added peer node the sequence number where it should
2369  * start receiving and acking broadcast packets.
2370  */
2371 static void tipc_link_build_bc_init_msg(struct tipc_link *l,
2372 					struct sk_buff_head *xmitq)
2373 {
2374 	struct sk_buff_head list;
2375 
2376 	__skb_queue_head_init(&list);
2377 	if (!tipc_link_build_bc_proto_msg(l->bc_rcvlink, false, 0, &list))
2378 		return;
2379 	msg_set_bc_ack_invalid(buf_msg(skb_peek(&list)), true);
2380 	tipc_link_xmit(l, &list, xmitq);
2381 }
2382 
2383 /* tipc_link_bc_init_rcv - receive initial broadcast synch data from peer
2384  */
2385 void tipc_link_bc_init_rcv(struct tipc_link *l, struct tipc_msg *hdr)
2386 {
2387 	int mtyp = msg_type(hdr);
2388 	u16 peers_snd_nxt = msg_bc_snd_nxt(hdr);
2389 
2390 	if (link_is_up(l))
2391 		return;
2392 
2393 	if (msg_user(hdr) == BCAST_PROTOCOL) {
2394 		l->rcv_nxt = peers_snd_nxt;
2395 		l->state = LINK_ESTABLISHED;
2396 		return;
2397 	}
2398 
2399 	if (l->peer_caps & TIPC_BCAST_SYNCH)
2400 		return;
2401 
2402 	if (msg_peer_node_is_up(hdr))
2403 		return;
2404 
2405 	/* Compatibility: accept older, less safe initial synch data */
2406 	if ((mtyp == RESET_MSG) || (mtyp == ACTIVATE_MSG))
2407 		l->rcv_nxt = peers_snd_nxt;
2408 }
2409 
2410 /* tipc_link_bc_sync_rcv - update rcv link according to peer's send state
2411  */
2412 int tipc_link_bc_sync_rcv(struct tipc_link *l, struct tipc_msg *hdr,
2413 			  struct sk_buff_head *xmitq)
2414 {
2415 	u16 peers_snd_nxt = msg_bc_snd_nxt(hdr);
2416 	int rc = 0;
2417 
2418 	if (!link_is_up(l))
2419 		return rc;
2420 
2421 	if (!msg_peer_node_is_up(hdr))
2422 		return rc;
2423 
2424 	/* Open when peer acknowledges our bcast init msg (pkt #1) */
2425 	if (msg_ack(hdr))
2426 		l->bc_peer_is_up = true;
2427 
2428 	if (!l->bc_peer_is_up)
2429 		return rc;
2430 
2431 	/* Ignore if peers_snd_nxt goes beyond receive window */
2432 	if (more(peers_snd_nxt, l->rcv_nxt + l->window))
2433 		return rc;
2434 
2435 	l->snd_nxt = peers_snd_nxt;
2436 	if (link_bc_rcv_gap(l))
2437 		rc |= TIPC_LINK_SND_STATE;
2438 
2439 	/* Return now if sender supports nack via STATE messages */
2440 	if (l->peer_caps & TIPC_BCAST_STATE_NACK)
2441 		return rc;
2442 
2443 	/* Otherwise, be backwards compatible */
2444 
2445 	if (!more(peers_snd_nxt, l->rcv_nxt)) {
2446 		l->nack_state = BC_NACK_SND_CONDITIONAL;
2447 		return 0;
2448 	}
2449 
2450 	/* Don't NACK if one was recently sent or peeked */
2451 	if (l->nack_state == BC_NACK_SND_SUPPRESS) {
2452 		l->nack_state = BC_NACK_SND_UNCONDITIONAL;
2453 		return 0;
2454 	}
2455 
2456 	/* Conditionally delay NACK sending until next synch rcv */
2457 	if (l->nack_state == BC_NACK_SND_CONDITIONAL) {
2458 		l->nack_state = BC_NACK_SND_UNCONDITIONAL;
2459 		if ((peers_snd_nxt - l->rcv_nxt) < TIPC_MIN_LINK_WIN)
2460 			return 0;
2461 	}
2462 
2463 	/* Send NACK now but suppress next one */
2464 	tipc_link_build_bc_proto_msg(l, true, peers_snd_nxt, xmitq);
2465 	l->nack_state = BC_NACK_SND_SUPPRESS;
2466 	return 0;
2467 }
2468 
2469 int tipc_link_bc_ack_rcv(struct tipc_link *r, u16 acked, u16 gap,
2470 			 struct tipc_gap_ack_blks *ga,
2471 			 struct sk_buff_head *xmitq,
2472 			 struct sk_buff_head *retrq)
2473 {
2474 	struct tipc_link *l = r->bc_sndlink;
2475 	bool unused = false;
2476 	int rc = 0;
2477 
2478 	if (!link_is_up(r) || !r->bc_peer_is_up)
2479 		return 0;
2480 
2481 	if (gap) {
2482 		l->stats.recv_nacks++;
2483 		r->stats.recv_nacks++;
2484 	}
2485 
2486 	if (less(acked, r->acked) || (acked == r->acked && !gap && !ga))
2487 		return 0;
2488 
2489 	trace_tipc_link_bc_ack(r, acked, gap, &l->transmq);
2490 	tipc_link_advance_transmq(l, r, acked, gap, ga, retrq, &unused, &rc);
2491 
2492 	tipc_link_advance_backlog(l, xmitq);
2493 	if (unlikely(!skb_queue_empty(&l->wakeupq)))
2494 		link_prepare_wakeup(l);
2495 
2496 	return rc;
2497 }
2498 
2499 /* tipc_link_bc_nack_rcv(): receive broadcast nack message
2500  * This function is here for backwards compatibility, since
2501  * no BCAST_PROTOCOL/STATE messages occur from TIPC v2.5.
2502  */
2503 int tipc_link_bc_nack_rcv(struct tipc_link *l, struct sk_buff *skb,
2504 			  struct sk_buff_head *xmitq)
2505 {
2506 	struct tipc_msg *hdr = buf_msg(skb);
2507 	u32 dnode = msg_destnode(hdr);
2508 	int mtyp = msg_type(hdr);
2509 	u16 acked = msg_bcast_ack(hdr);
2510 	u16 from = acked + 1;
2511 	u16 to = msg_bcgap_to(hdr);
2512 	u16 peers_snd_nxt = to + 1;
2513 	int rc = 0;
2514 
2515 	kfree_skb(skb);
2516 
2517 	if (!tipc_link_is_up(l) || !l->bc_peer_is_up)
2518 		return 0;
2519 
2520 	if (mtyp != STATE_MSG)
2521 		return 0;
2522 
2523 	if (dnode == tipc_own_addr(l->net)) {
2524 		rc = tipc_link_bc_ack_rcv(l, acked, to - acked, NULL, xmitq,
2525 					  xmitq);
2526 		l->stats.recv_nacks++;
2527 		return rc;
2528 	}
2529 
2530 	/* Msg for other node => suppress own NACK at next sync if applicable */
2531 	if (more(peers_snd_nxt, l->rcv_nxt) && !less(l->rcv_nxt, from))
2532 		l->nack_state = BC_NACK_SND_SUPPRESS;
2533 
2534 	return 0;
2535 }
2536 
2537 void tipc_link_set_queue_limits(struct tipc_link *l, u32 min_win, u32 max_win)
2538 {
2539 	int max_bulk = TIPC_MAX_PUBL / (l->mtu / ITEM_SIZE);
2540 
2541 	l->min_win = min_win;
2542 	l->ssthresh = max_win;
2543 	l->max_win = max_win;
2544 	l->window = min_win;
2545 	l->backlog[TIPC_LOW_IMPORTANCE].limit      = min_win * 2;
2546 	l->backlog[TIPC_MEDIUM_IMPORTANCE].limit   = min_win * 4;
2547 	l->backlog[TIPC_HIGH_IMPORTANCE].limit     = min_win * 6;
2548 	l->backlog[TIPC_CRITICAL_IMPORTANCE].limit = min_win * 8;
2549 	l->backlog[TIPC_SYSTEM_IMPORTANCE].limit   = max_bulk;
2550 }
2551 
2552 /**
2553  * tipc_link_reset_stats - reset link statistics
2554  * @l: pointer to link
2555  */
2556 void tipc_link_reset_stats(struct tipc_link *l)
2557 {
2558 	memset(&l->stats, 0, sizeof(l->stats));
2559 }
2560 
2561 static void link_print(struct tipc_link *l, const char *str)
2562 {
2563 	struct sk_buff *hskb = skb_peek(&l->transmq);
2564 	u16 head = hskb ? msg_seqno(buf_msg(hskb)) : l->snd_nxt - 1;
2565 	u16 tail = l->snd_nxt - 1;
2566 
2567 	pr_info("%s Link <%s> state %x\n", str, l->name, l->state);
2568 	pr_info("XMTQ: %u [%u-%u], BKLGQ: %u, SNDNX: %u, RCVNX: %u\n",
2569 		skb_queue_len(&l->transmq), head, tail,
2570 		skb_queue_len(&l->backlogq), l->snd_nxt, l->rcv_nxt);
2571 }
2572 
2573 /* Parse and validate nested (link) properties valid for media, bearer and link
2574  */
2575 int tipc_nl_parse_link_prop(struct nlattr *prop, struct nlattr *props[])
2576 {
2577 	int err;
2578 
2579 	err = nla_parse_nested_deprecated(props, TIPC_NLA_PROP_MAX, prop,
2580 					  tipc_nl_prop_policy, NULL);
2581 	if (err)
2582 		return err;
2583 
2584 	if (props[TIPC_NLA_PROP_PRIO]) {
2585 		u32 prio;
2586 
2587 		prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
2588 		if (prio > TIPC_MAX_LINK_PRI)
2589 			return -EINVAL;
2590 	}
2591 
2592 	if (props[TIPC_NLA_PROP_TOL]) {
2593 		u32 tol;
2594 
2595 		tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
2596 		if ((tol < TIPC_MIN_LINK_TOL) || (tol > TIPC_MAX_LINK_TOL))
2597 			return -EINVAL;
2598 	}
2599 
2600 	if (props[TIPC_NLA_PROP_WIN]) {
2601 		u32 max_win;
2602 
2603 		max_win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
2604 		if (max_win < TIPC_DEF_LINK_WIN || max_win > TIPC_MAX_LINK_WIN)
2605 			return -EINVAL;
2606 	}
2607 
2608 	return 0;
2609 }
2610 
2611 static int __tipc_nl_add_stats(struct sk_buff *skb, struct tipc_stats *s)
2612 {
2613 	int i;
2614 	struct nlattr *stats;
2615 
2616 	struct nla_map {
2617 		u32 key;
2618 		u32 val;
2619 	};
2620 
2621 	struct nla_map map[] = {
2622 		{TIPC_NLA_STATS_RX_INFO, 0},
2623 		{TIPC_NLA_STATS_RX_FRAGMENTS, s->recv_fragments},
2624 		{TIPC_NLA_STATS_RX_FRAGMENTED, s->recv_fragmented},
2625 		{TIPC_NLA_STATS_RX_BUNDLES, s->recv_bundles},
2626 		{TIPC_NLA_STATS_RX_BUNDLED, s->recv_bundled},
2627 		{TIPC_NLA_STATS_TX_INFO, 0},
2628 		{TIPC_NLA_STATS_TX_FRAGMENTS, s->sent_fragments},
2629 		{TIPC_NLA_STATS_TX_FRAGMENTED, s->sent_fragmented},
2630 		{TIPC_NLA_STATS_TX_BUNDLES, s->sent_bundles},
2631 		{TIPC_NLA_STATS_TX_BUNDLED, s->sent_bundled},
2632 		{TIPC_NLA_STATS_MSG_PROF_TOT, (s->msg_length_counts) ?
2633 			s->msg_length_counts : 1},
2634 		{TIPC_NLA_STATS_MSG_LEN_CNT, s->msg_length_counts},
2635 		{TIPC_NLA_STATS_MSG_LEN_TOT, s->msg_lengths_total},
2636 		{TIPC_NLA_STATS_MSG_LEN_P0, s->msg_length_profile[0]},
2637 		{TIPC_NLA_STATS_MSG_LEN_P1, s->msg_length_profile[1]},
2638 		{TIPC_NLA_STATS_MSG_LEN_P2, s->msg_length_profile[2]},
2639 		{TIPC_NLA_STATS_MSG_LEN_P3, s->msg_length_profile[3]},
2640 		{TIPC_NLA_STATS_MSG_LEN_P4, s->msg_length_profile[4]},
2641 		{TIPC_NLA_STATS_MSG_LEN_P5, s->msg_length_profile[5]},
2642 		{TIPC_NLA_STATS_MSG_LEN_P6, s->msg_length_profile[6]},
2643 		{TIPC_NLA_STATS_RX_STATES, s->recv_states},
2644 		{TIPC_NLA_STATS_RX_PROBES, s->recv_probes},
2645 		{TIPC_NLA_STATS_RX_NACKS, s->recv_nacks},
2646 		{TIPC_NLA_STATS_RX_DEFERRED, s->deferred_recv},
2647 		{TIPC_NLA_STATS_TX_STATES, s->sent_states},
2648 		{TIPC_NLA_STATS_TX_PROBES, s->sent_probes},
2649 		{TIPC_NLA_STATS_TX_NACKS, s->sent_nacks},
2650 		{TIPC_NLA_STATS_TX_ACKS, s->sent_acks},
2651 		{TIPC_NLA_STATS_RETRANSMITTED, s->retransmitted},
2652 		{TIPC_NLA_STATS_DUPLICATES, s->duplicates},
2653 		{TIPC_NLA_STATS_LINK_CONGS, s->link_congs},
2654 		{TIPC_NLA_STATS_MAX_QUEUE, s->max_queue_sz},
2655 		{TIPC_NLA_STATS_AVG_QUEUE, s->queue_sz_counts ?
2656 			(s->accu_queue_sz / s->queue_sz_counts) : 0}
2657 	};
2658 
2659 	stats = nla_nest_start_noflag(skb, TIPC_NLA_LINK_STATS);
2660 	if (!stats)
2661 		return -EMSGSIZE;
2662 
2663 	for (i = 0; i <  ARRAY_SIZE(map); i++)
2664 		if (nla_put_u32(skb, map[i].key, map[i].val))
2665 			goto msg_full;
2666 
2667 	nla_nest_end(skb, stats);
2668 
2669 	return 0;
2670 msg_full:
2671 	nla_nest_cancel(skb, stats);
2672 
2673 	return -EMSGSIZE;
2674 }
2675 
2676 /* Caller should hold appropriate locks to protect the link */
2677 int __tipc_nl_add_link(struct net *net, struct tipc_nl_msg *msg,
2678 		       struct tipc_link *link, int nlflags)
2679 {
2680 	u32 self = tipc_own_addr(net);
2681 	struct nlattr *attrs;
2682 	struct nlattr *prop;
2683 	void *hdr;
2684 	int err;
2685 
2686 	hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
2687 			  nlflags, TIPC_NL_LINK_GET);
2688 	if (!hdr)
2689 		return -EMSGSIZE;
2690 
2691 	attrs = nla_nest_start_noflag(msg->skb, TIPC_NLA_LINK);
2692 	if (!attrs)
2693 		goto msg_full;
2694 
2695 	if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, link->name))
2696 		goto attr_msg_full;
2697 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_DEST, tipc_cluster_mask(self)))
2698 		goto attr_msg_full;
2699 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_MTU, link->mtu))
2700 		goto attr_msg_full;
2701 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, link->stats.recv_pkts))
2702 		goto attr_msg_full;
2703 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, link->stats.sent_pkts))
2704 		goto attr_msg_full;
2705 
2706 	if (tipc_link_is_up(link))
2707 		if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
2708 			goto attr_msg_full;
2709 	if (link->active)
2710 		if (nla_put_flag(msg->skb, TIPC_NLA_LINK_ACTIVE))
2711 			goto attr_msg_full;
2712 
2713 	prop = nla_nest_start_noflag(msg->skb, TIPC_NLA_LINK_PROP);
2714 	if (!prop)
2715 		goto attr_msg_full;
2716 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
2717 		goto prop_msg_full;
2718 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_TOL, link->tolerance))
2719 		goto prop_msg_full;
2720 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN,
2721 			link->window))
2722 		goto prop_msg_full;
2723 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
2724 		goto prop_msg_full;
2725 	nla_nest_end(msg->skb, prop);
2726 
2727 	err = __tipc_nl_add_stats(msg->skb, &link->stats);
2728 	if (err)
2729 		goto attr_msg_full;
2730 
2731 	nla_nest_end(msg->skb, attrs);
2732 	genlmsg_end(msg->skb, hdr);
2733 
2734 	return 0;
2735 
2736 prop_msg_full:
2737 	nla_nest_cancel(msg->skb, prop);
2738 attr_msg_full:
2739 	nla_nest_cancel(msg->skb, attrs);
2740 msg_full:
2741 	genlmsg_cancel(msg->skb, hdr);
2742 
2743 	return -EMSGSIZE;
2744 }
2745 
2746 static int __tipc_nl_add_bc_link_stat(struct sk_buff *skb,
2747 				      struct tipc_stats *stats)
2748 {
2749 	int i;
2750 	struct nlattr *nest;
2751 
2752 	struct nla_map {
2753 		__u32 key;
2754 		__u32 val;
2755 	};
2756 
2757 	struct nla_map map[] = {
2758 		{TIPC_NLA_STATS_RX_INFO, stats->recv_pkts},
2759 		{TIPC_NLA_STATS_RX_FRAGMENTS, stats->recv_fragments},
2760 		{TIPC_NLA_STATS_RX_FRAGMENTED, stats->recv_fragmented},
2761 		{TIPC_NLA_STATS_RX_BUNDLES, stats->recv_bundles},
2762 		{TIPC_NLA_STATS_RX_BUNDLED, stats->recv_bundled},
2763 		{TIPC_NLA_STATS_TX_INFO, stats->sent_pkts},
2764 		{TIPC_NLA_STATS_TX_FRAGMENTS, stats->sent_fragments},
2765 		{TIPC_NLA_STATS_TX_FRAGMENTED, stats->sent_fragmented},
2766 		{TIPC_NLA_STATS_TX_BUNDLES, stats->sent_bundles},
2767 		{TIPC_NLA_STATS_TX_BUNDLED, stats->sent_bundled},
2768 		{TIPC_NLA_STATS_RX_NACKS, stats->recv_nacks},
2769 		{TIPC_NLA_STATS_RX_DEFERRED, stats->deferred_recv},
2770 		{TIPC_NLA_STATS_TX_NACKS, stats->sent_nacks},
2771 		{TIPC_NLA_STATS_TX_ACKS, stats->sent_acks},
2772 		{TIPC_NLA_STATS_RETRANSMITTED, stats->retransmitted},
2773 		{TIPC_NLA_STATS_DUPLICATES, stats->duplicates},
2774 		{TIPC_NLA_STATS_LINK_CONGS, stats->link_congs},
2775 		{TIPC_NLA_STATS_MAX_QUEUE, stats->max_queue_sz},
2776 		{TIPC_NLA_STATS_AVG_QUEUE, stats->queue_sz_counts ?
2777 			(stats->accu_queue_sz / stats->queue_sz_counts) : 0}
2778 	};
2779 
2780 	nest = nla_nest_start_noflag(skb, TIPC_NLA_LINK_STATS);
2781 	if (!nest)
2782 		return -EMSGSIZE;
2783 
2784 	for (i = 0; i <  ARRAY_SIZE(map); i++)
2785 		if (nla_put_u32(skb, map[i].key, map[i].val))
2786 			goto msg_full;
2787 
2788 	nla_nest_end(skb, nest);
2789 
2790 	return 0;
2791 msg_full:
2792 	nla_nest_cancel(skb, nest);
2793 
2794 	return -EMSGSIZE;
2795 }
2796 
2797 int tipc_nl_add_bc_link(struct net *net, struct tipc_nl_msg *msg,
2798 			struct tipc_link *bcl)
2799 {
2800 	int err;
2801 	void *hdr;
2802 	struct nlattr *attrs;
2803 	struct nlattr *prop;
2804 	u32 bc_mode = tipc_bcast_get_mode(net);
2805 	u32 bc_ratio = tipc_bcast_get_broadcast_ratio(net);
2806 
2807 	if (!bcl)
2808 		return 0;
2809 
2810 	tipc_bcast_lock(net);
2811 
2812 	hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
2813 			  NLM_F_MULTI, TIPC_NL_LINK_GET);
2814 	if (!hdr) {
2815 		tipc_bcast_unlock(net);
2816 		return -EMSGSIZE;
2817 	}
2818 
2819 	attrs = nla_nest_start_noflag(msg->skb, TIPC_NLA_LINK);
2820 	if (!attrs)
2821 		goto msg_full;
2822 
2823 	/* The broadcast link is always up */
2824 	if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
2825 		goto attr_msg_full;
2826 
2827 	if (nla_put_flag(msg->skb, TIPC_NLA_LINK_BROADCAST))
2828 		goto attr_msg_full;
2829 	if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, bcl->name))
2830 		goto attr_msg_full;
2831 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, 0))
2832 		goto attr_msg_full;
2833 	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, 0))
2834 		goto attr_msg_full;
2835 
2836 	prop = nla_nest_start_noflag(msg->skb, TIPC_NLA_LINK_PROP);
2837 	if (!prop)
2838 		goto attr_msg_full;
2839 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN, bcl->max_win))
2840 		goto prop_msg_full;
2841 	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_BROADCAST, bc_mode))
2842 		goto prop_msg_full;
2843 	if (bc_mode & BCLINK_MODE_SEL)
2844 		if (nla_put_u32(msg->skb, TIPC_NLA_PROP_BROADCAST_RATIO,
2845 				bc_ratio))
2846 			goto prop_msg_full;
2847 	nla_nest_end(msg->skb, prop);
2848 
2849 	err = __tipc_nl_add_bc_link_stat(msg->skb, &bcl->stats);
2850 	if (err)
2851 		goto attr_msg_full;
2852 
2853 	tipc_bcast_unlock(net);
2854 	nla_nest_end(msg->skb, attrs);
2855 	genlmsg_end(msg->skb, hdr);
2856 
2857 	return 0;
2858 
2859 prop_msg_full:
2860 	nla_nest_cancel(msg->skb, prop);
2861 attr_msg_full:
2862 	nla_nest_cancel(msg->skb, attrs);
2863 msg_full:
2864 	tipc_bcast_unlock(net);
2865 	genlmsg_cancel(msg->skb, hdr);
2866 
2867 	return -EMSGSIZE;
2868 }
2869 
2870 void tipc_link_set_tolerance(struct tipc_link *l, u32 tol,
2871 			     struct sk_buff_head *xmitq)
2872 {
2873 	l->tolerance = tol;
2874 	if (l->bc_rcvlink)
2875 		l->bc_rcvlink->tolerance = tol;
2876 	if (link_is_up(l))
2877 		tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, tol, 0, xmitq);
2878 }
2879 
2880 void tipc_link_set_prio(struct tipc_link *l, u32 prio,
2881 			struct sk_buff_head *xmitq)
2882 {
2883 	l->priority = prio;
2884 	tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, 0, prio, xmitq);
2885 }
2886 
2887 void tipc_link_set_abort_limit(struct tipc_link *l, u32 limit)
2888 {
2889 	l->abort_limit = limit;
2890 }
2891 
2892 /**
2893  * tipc_link_dump - dump TIPC link data
2894  * @l: tipc link to be dumped
2895  * @dqueues: bitmask to decide if any link queue to be dumped?
2896  *           - TIPC_DUMP_NONE: don't dump link queues
2897  *           - TIPC_DUMP_TRANSMQ: dump link transmq queue
2898  *           - TIPC_DUMP_BACKLOGQ: dump link backlog queue
2899  *           - TIPC_DUMP_DEFERDQ: dump link deferd queue
2900  *           - TIPC_DUMP_INPUTQ: dump link input queue
2901  *           - TIPC_DUMP_WAKEUP: dump link wakeup queue
2902  *           - TIPC_DUMP_ALL: dump all the link queues above
2903  * @buf: returned buffer of dump data in format
2904  */
2905 int tipc_link_dump(struct tipc_link *l, u16 dqueues, char *buf)
2906 {
2907 	int i = 0;
2908 	size_t sz = (dqueues) ? LINK_LMAX : LINK_LMIN;
2909 	struct sk_buff_head *list;
2910 	struct sk_buff *hskb, *tskb;
2911 	u32 len;
2912 
2913 	if (!l) {
2914 		i += scnprintf(buf, sz, "link data: (null)\n");
2915 		return i;
2916 	}
2917 
2918 	i += scnprintf(buf, sz, "link data: %x", l->addr);
2919 	i += scnprintf(buf + i, sz - i, " %x", l->state);
2920 	i += scnprintf(buf + i, sz - i, " %u", l->in_session);
2921 	i += scnprintf(buf + i, sz - i, " %u", l->session);
2922 	i += scnprintf(buf + i, sz - i, " %u", l->peer_session);
2923 	i += scnprintf(buf + i, sz - i, " %u", l->snd_nxt);
2924 	i += scnprintf(buf + i, sz - i, " %u", l->rcv_nxt);
2925 	i += scnprintf(buf + i, sz - i, " %u", l->snd_nxt_state);
2926 	i += scnprintf(buf + i, sz - i, " %u", l->rcv_nxt_state);
2927 	i += scnprintf(buf + i, sz - i, " %x", l->peer_caps);
2928 	i += scnprintf(buf + i, sz - i, " %u", l->silent_intv_cnt);
2929 	i += scnprintf(buf + i, sz - i, " %u", l->rst_cnt);
2930 	i += scnprintf(buf + i, sz - i, " %u", 0);
2931 	i += scnprintf(buf + i, sz - i, " %u", 0);
2932 	i += scnprintf(buf + i, sz - i, " %u", l->acked);
2933 
2934 	list = &l->transmq;
2935 	len = skb_queue_len(list);
2936 	hskb = skb_peek(list);
2937 	tskb = skb_peek_tail(list);
2938 	i += scnprintf(buf + i, sz - i, " | %u %u %u", len,
2939 		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
2940 		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
2941 
2942 	list = &l->deferdq;
2943 	len = skb_queue_len(list);
2944 	hskb = skb_peek(list);
2945 	tskb = skb_peek_tail(list);
2946 	i += scnprintf(buf + i, sz - i, " | %u %u %u", len,
2947 		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
2948 		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
2949 
2950 	list = &l->backlogq;
2951 	len = skb_queue_len(list);
2952 	hskb = skb_peek(list);
2953 	tskb = skb_peek_tail(list);
2954 	i += scnprintf(buf + i, sz - i, " | %u %u %u", len,
2955 		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
2956 		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
2957 
2958 	list = l->inputq;
2959 	len = skb_queue_len(list);
2960 	hskb = skb_peek(list);
2961 	tskb = skb_peek_tail(list);
2962 	i += scnprintf(buf + i, sz - i, " | %u %u %u\n", len,
2963 		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
2964 		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);
2965 
2966 	if (dqueues & TIPC_DUMP_TRANSMQ) {
2967 		i += scnprintf(buf + i, sz - i, "transmq: ");
2968 		i += tipc_list_dump(&l->transmq, false, buf + i);
2969 	}
2970 	if (dqueues & TIPC_DUMP_BACKLOGQ) {
2971 		i += scnprintf(buf + i, sz - i,
2972 			       "backlogq: <%u %u %u %u %u>, ",
2973 			       l->backlog[TIPC_LOW_IMPORTANCE].len,
2974 			       l->backlog[TIPC_MEDIUM_IMPORTANCE].len,
2975 			       l->backlog[TIPC_HIGH_IMPORTANCE].len,
2976 			       l->backlog[TIPC_CRITICAL_IMPORTANCE].len,
2977 			       l->backlog[TIPC_SYSTEM_IMPORTANCE].len);
2978 		i += tipc_list_dump(&l->backlogq, false, buf + i);
2979 	}
2980 	if (dqueues & TIPC_DUMP_DEFERDQ) {
2981 		i += scnprintf(buf + i, sz - i, "deferdq: ");
2982 		i += tipc_list_dump(&l->deferdq, false, buf + i);
2983 	}
2984 	if (dqueues & TIPC_DUMP_INPUTQ) {
2985 		i += scnprintf(buf + i, sz - i, "inputq: ");
2986 		i += tipc_list_dump(l->inputq, false, buf + i);
2987 	}
2988 	if (dqueues & TIPC_DUMP_WAKEUP) {
2989 		i += scnprintf(buf + i, sz - i, "wakeup: ");
2990 		i += tipc_list_dump(&l->wakeupq, false, buf + i);
2991 	}
2992 
2993 	return i;
2994 }
2995