xref: /openbmc/linux/net/tipc/group.c (revision 133f9794)
1 /*
2  * net/tipc/group.c: TIPC group messaging code
3  *
4  * Copyright (c) 2017, Ericsson AB
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions are met:
9  *
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the names of the copyright holders nor the names of its
16  *    contributors may be used to endorse or promote products derived from
17  *    this software without specific prior written permission.
18  *
19  * Alternatively, this software may be distributed under the terms of the
20  * GNU General Public License ("GPL") version 2 as published by the Free
21  * Software Foundation.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
24  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
27  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
28  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
29  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
30  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
31  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
32  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
33  * POSSIBILITY OF SUCH DAMAGE.
34  */
35 
36 #include "core.h"
37 #include "addr.h"
38 #include "group.h"
39 #include "bcast.h"
40 #include "server.h"
41 #include "msg.h"
42 #include "socket.h"
43 #include "node.h"
44 #include "name_table.h"
45 #include "subscr.h"
46 
47 #define ADV_UNIT (((MAX_MSG_SIZE + MAX_H_SIZE) / FLOWCTL_BLK_SZ) + 1)
48 #define ADV_IDLE ADV_UNIT
49 #define ADV_ACTIVE (ADV_UNIT * 12)
50 
51 enum mbr_state {
52 	MBR_JOINING,
53 	MBR_PUBLISHED,
54 	MBR_JOINED,
55 	MBR_PENDING,
56 	MBR_ACTIVE,
57 	MBR_RECLAIMING,
58 	MBR_REMITTED,
59 	MBR_LEAVING
60 };
61 
62 struct tipc_member {
63 	struct rb_node tree_node;
64 	struct list_head list;
65 	struct list_head small_win;
66 	struct sk_buff_head deferredq;
67 	struct tipc_group *group;
68 	u32 node;
69 	u32 port;
70 	u32 instance;
71 	enum mbr_state state;
72 	u16 advertised;
73 	u16 window;
74 	u16 bc_rcv_nxt;
75 	u16 bc_syncpt;
76 	u16 bc_acked;
77 };
78 
79 struct tipc_group {
80 	struct rb_root members;
81 	struct list_head small_win;
82 	struct list_head pending;
83 	struct list_head active;
84 	struct tipc_nlist dests;
85 	struct net *net;
86 	int subid;
87 	u32 type;
88 	u32 instance;
89 	u32 scope;
90 	u32 portid;
91 	u16 member_cnt;
92 	u16 active_cnt;
93 	u16 max_active;
94 	u16 bc_snd_nxt;
95 	u16 bc_ackers;
96 	bool *open;
97 	bool loopback;
98 	bool events;
99 };
100 
101 static void tipc_group_proto_xmit(struct tipc_group *grp, struct tipc_member *m,
102 				  int mtyp, struct sk_buff_head *xmitq);
103 
104 static void tipc_group_open(struct tipc_member *m, bool *wakeup)
105 {
106 	*wakeup = false;
107 	if (list_empty(&m->small_win))
108 		return;
109 	list_del_init(&m->small_win);
110 	*m->group->open = true;
111 	*wakeup = true;
112 }
113 
114 static void tipc_group_decr_active(struct tipc_group *grp,
115 				   struct tipc_member *m)
116 {
117 	if (m->state == MBR_ACTIVE || m->state == MBR_RECLAIMING ||
118 	    m->state == MBR_REMITTED)
119 		grp->active_cnt--;
120 }
121 
122 static int tipc_group_rcvbuf_limit(struct tipc_group *grp)
123 {
124 	int max_active, active_pool, idle_pool;
125 	int mcnt = grp->member_cnt + 1;
126 
127 	/* Limit simultaneous reception from other members */
128 	max_active = min(mcnt / 8, 64);
129 	max_active = max(max_active, 16);
130 	grp->max_active = max_active;
131 
132 	/* Reserve blocks for active and idle members */
133 	active_pool = max_active * ADV_ACTIVE;
134 	idle_pool = (mcnt - max_active) * ADV_IDLE;
135 
136 	/* Scale to bytes, considering worst-case truesize/msgsize ratio */
137 	return (active_pool + idle_pool) * FLOWCTL_BLK_SZ * 4;
138 }
139 
140 u16 tipc_group_bc_snd_nxt(struct tipc_group *grp)
141 {
142 	return grp->bc_snd_nxt;
143 }
144 
145 static bool tipc_group_is_receiver(struct tipc_member *m)
146 {
147 	return m && m->state != MBR_JOINING && m->state != MBR_LEAVING;
148 }
149 
150 static bool tipc_group_is_sender(struct tipc_member *m)
151 {
152 	return m && m->state != MBR_JOINING && m->state != MBR_PUBLISHED;
153 }
154 
155 u32 tipc_group_exclude(struct tipc_group *grp)
156 {
157 	if (!grp->loopback)
158 		return grp->portid;
159 	return 0;
160 }
161 
162 int tipc_group_size(struct tipc_group *grp)
163 {
164 	return grp->member_cnt;
165 }
166 
167 struct tipc_group *tipc_group_create(struct net *net, u32 portid,
168 				     struct tipc_group_req *mreq,
169 				     bool *group_is_open)
170 {
171 	u32 filter = TIPC_SUB_PORTS | TIPC_SUB_NO_STATUS;
172 	bool global = mreq->scope != TIPC_NODE_SCOPE;
173 	struct tipc_group *grp;
174 	u32 type = mreq->type;
175 
176 	grp = kzalloc(sizeof(*grp), GFP_ATOMIC);
177 	if (!grp)
178 		return NULL;
179 	tipc_nlist_init(&grp->dests, tipc_own_addr(net));
180 	INIT_LIST_HEAD(&grp->small_win);
181 	INIT_LIST_HEAD(&grp->active);
182 	INIT_LIST_HEAD(&grp->pending);
183 	grp->members = RB_ROOT;
184 	grp->net = net;
185 	grp->portid = portid;
186 	grp->type = type;
187 	grp->instance = mreq->instance;
188 	grp->scope = mreq->scope;
189 	grp->loopback = mreq->flags & TIPC_GROUP_LOOPBACK;
190 	grp->events = mreq->flags & TIPC_GROUP_MEMBER_EVTS;
191 	grp->open = group_is_open;
192 	filter |= global ? TIPC_SUB_CLUSTER_SCOPE : TIPC_SUB_NODE_SCOPE;
193 	if (tipc_topsrv_kern_subscr(net, portid, type, 0, ~0,
194 				    filter, &grp->subid))
195 		return grp;
196 	kfree(grp);
197 	return NULL;
198 }
199 
200 void tipc_group_join(struct net *net, struct tipc_group *grp, int *sk_rcvbuf)
201 {
202 	struct rb_root *tree = &grp->members;
203 	struct tipc_member *m, *tmp;
204 	struct sk_buff_head xmitq;
205 
206 	skb_queue_head_init(&xmitq);
207 	rbtree_postorder_for_each_entry_safe(m, tmp, tree, tree_node) {
208 		tipc_group_proto_xmit(grp, m, GRP_JOIN_MSG, &xmitq);
209 		tipc_group_update_member(m, 0);
210 	}
211 	tipc_node_distr_xmit(net, &xmitq);
212 	*sk_rcvbuf = tipc_group_rcvbuf_limit(grp);
213 }
214 
215 void tipc_group_delete(struct net *net, struct tipc_group *grp)
216 {
217 	struct rb_root *tree = &grp->members;
218 	struct tipc_member *m, *tmp;
219 	struct sk_buff_head xmitq;
220 
221 	__skb_queue_head_init(&xmitq);
222 
223 	rbtree_postorder_for_each_entry_safe(m, tmp, tree, tree_node) {
224 		tipc_group_proto_xmit(grp, m, GRP_LEAVE_MSG, &xmitq);
225 		list_del(&m->list);
226 		kfree(m);
227 	}
228 	tipc_node_distr_xmit(net, &xmitq);
229 	tipc_nlist_purge(&grp->dests);
230 	tipc_topsrv_kern_unsubscr(net, grp->subid);
231 	kfree(grp);
232 }
233 
234 struct tipc_member *tipc_group_find_member(struct tipc_group *grp,
235 					   u32 node, u32 port)
236 {
237 	struct rb_node *n = grp->members.rb_node;
238 	u64 nkey, key = (u64)node << 32 | port;
239 	struct tipc_member *m;
240 
241 	while (n) {
242 		m = container_of(n, struct tipc_member, tree_node);
243 		nkey = (u64)m->node << 32 | m->port;
244 		if (key < nkey)
245 			n = n->rb_left;
246 		else if (key > nkey)
247 			n = n->rb_right;
248 		else
249 			return m;
250 	}
251 	return NULL;
252 }
253 
254 static struct tipc_member *tipc_group_find_dest(struct tipc_group *grp,
255 						u32 node, u32 port)
256 {
257 	struct tipc_member *m;
258 
259 	m = tipc_group_find_member(grp, node, port);
260 	if (m && tipc_group_is_receiver(m))
261 		return m;
262 	return NULL;
263 }
264 
265 static struct tipc_member *tipc_group_find_node(struct tipc_group *grp,
266 						u32 node)
267 {
268 	struct tipc_member *m;
269 	struct rb_node *n;
270 
271 	for (n = rb_first(&grp->members); n; n = rb_next(n)) {
272 		m = container_of(n, struct tipc_member, tree_node);
273 		if (m->node == node)
274 			return m;
275 	}
276 	return NULL;
277 }
278 
279 static void tipc_group_add_to_tree(struct tipc_group *grp,
280 				   struct tipc_member *m)
281 {
282 	u64 nkey, key = (u64)m->node << 32 | m->port;
283 	struct rb_node **n, *parent = NULL;
284 	struct tipc_member *tmp;
285 
286 	n = &grp->members.rb_node;
287 	while (*n) {
288 		tmp = container_of(*n, struct tipc_member, tree_node);
289 		parent = *n;
290 		tmp = container_of(parent, struct tipc_member, tree_node);
291 		nkey = (u64)tmp->node << 32 | tmp->port;
292 		if (key < nkey)
293 			n = &(*n)->rb_left;
294 		else if (key > nkey)
295 			n = &(*n)->rb_right;
296 		else
297 			return;
298 	}
299 	rb_link_node(&m->tree_node, parent, n);
300 	rb_insert_color(&m->tree_node, &grp->members);
301 }
302 
303 static struct tipc_member *tipc_group_create_member(struct tipc_group *grp,
304 						    u32 node, u32 port,
305 						    u32 instance, int state)
306 {
307 	struct tipc_member *m;
308 
309 	m = kzalloc(sizeof(*m), GFP_ATOMIC);
310 	if (!m)
311 		return NULL;
312 	INIT_LIST_HEAD(&m->list);
313 	INIT_LIST_HEAD(&m->small_win);
314 	__skb_queue_head_init(&m->deferredq);
315 	m->group = grp;
316 	m->node = node;
317 	m->port = port;
318 	m->instance = instance;
319 	m->bc_acked = grp->bc_snd_nxt - 1;
320 	grp->member_cnt++;
321 	tipc_group_add_to_tree(grp, m);
322 	tipc_nlist_add(&grp->dests, m->node);
323 	m->state = state;
324 	return m;
325 }
326 
327 void tipc_group_add_member(struct tipc_group *grp, u32 node,
328 			   u32 port, u32 instance)
329 {
330 	tipc_group_create_member(grp, node, port, instance, MBR_PUBLISHED);
331 }
332 
333 static void tipc_group_delete_member(struct tipc_group *grp,
334 				     struct tipc_member *m)
335 {
336 	rb_erase(&m->tree_node, &grp->members);
337 	grp->member_cnt--;
338 
339 	/* Check if we were waiting for replicast ack from this member */
340 	if (grp->bc_ackers && less(m->bc_acked, grp->bc_snd_nxt - 1))
341 		grp->bc_ackers--;
342 
343 	list_del_init(&m->list);
344 	list_del_init(&m->small_win);
345 	tipc_group_decr_active(grp, m);
346 
347 	/* If last member on a node, remove node from dest list */
348 	if (!tipc_group_find_node(grp, m->node))
349 		tipc_nlist_del(&grp->dests, m->node);
350 
351 	kfree(m);
352 }
353 
354 struct tipc_nlist *tipc_group_dests(struct tipc_group *grp)
355 {
356 	return &grp->dests;
357 }
358 
359 void tipc_group_self(struct tipc_group *grp, struct tipc_name_seq *seq,
360 		     int *scope)
361 {
362 	seq->type = grp->type;
363 	seq->lower = grp->instance;
364 	seq->upper = grp->instance;
365 	*scope = grp->scope;
366 }
367 
368 void tipc_group_update_member(struct tipc_member *m, int len)
369 {
370 	struct tipc_group *grp = m->group;
371 	struct tipc_member *_m, *tmp;
372 
373 	if (!tipc_group_is_receiver(m))
374 		return;
375 
376 	m->window -= len;
377 
378 	if (m->window >= ADV_IDLE)
379 		return;
380 
381 	list_del_init(&m->small_win);
382 
383 	/* Sort member into small_window members' list */
384 	list_for_each_entry_safe(_m, tmp, &grp->small_win, small_win) {
385 		if (_m->window > m->window)
386 			break;
387 	}
388 	list_add_tail(&m->small_win, &_m->small_win);
389 }
390 
391 void tipc_group_update_bc_members(struct tipc_group *grp, int len, bool ack)
392 {
393 	u16 prev = grp->bc_snd_nxt - 1;
394 	struct tipc_member *m;
395 	struct rb_node *n;
396 	u16 ackers = 0;
397 
398 	for (n = rb_first(&grp->members); n; n = rb_next(n)) {
399 		m = container_of(n, struct tipc_member, tree_node);
400 		if (tipc_group_is_receiver(m)) {
401 			tipc_group_update_member(m, len);
402 			m->bc_acked = prev;
403 			ackers++;
404 		}
405 	}
406 
407 	/* Mark number of acknowledges to expect, if any */
408 	if (ack)
409 		grp->bc_ackers = ackers;
410 	grp->bc_snd_nxt++;
411 }
412 
413 bool tipc_group_cong(struct tipc_group *grp, u32 dnode, u32 dport,
414 		     int len, struct tipc_member **mbr)
415 {
416 	struct sk_buff_head xmitq;
417 	struct tipc_member *m;
418 	int adv, state;
419 
420 	m = tipc_group_find_dest(grp, dnode, dport);
421 	if (!tipc_group_is_receiver(m)) {
422 		*mbr = NULL;
423 		return false;
424 	}
425 	*mbr = m;
426 
427 	if (m->window >= len)
428 		return false;
429 
430 	*grp->open = false;
431 
432 	/* If not fully advertised, do it now to prevent mutual blocking */
433 	adv = m->advertised;
434 	state = m->state;
435 	if (state == MBR_JOINED && adv == ADV_IDLE)
436 		return true;
437 	if (state == MBR_ACTIVE && adv == ADV_ACTIVE)
438 		return true;
439 	if (state == MBR_PENDING && adv == ADV_IDLE)
440 		return true;
441 	skb_queue_head_init(&xmitq);
442 	tipc_group_proto_xmit(grp, m, GRP_ADV_MSG, &xmitq);
443 	tipc_node_distr_xmit(grp->net, &xmitq);
444 	return true;
445 }
446 
447 bool tipc_group_bc_cong(struct tipc_group *grp, int len)
448 {
449 	struct tipc_member *m = NULL;
450 
451 	/* If prev bcast was replicast, reject until all receivers have acked */
452 	if (grp->bc_ackers) {
453 		*grp->open = false;
454 		return true;
455 	}
456 	if (list_empty(&grp->small_win))
457 		return false;
458 
459 	m = list_first_entry(&grp->small_win, struct tipc_member, small_win);
460 	if (m->window >= len)
461 		return false;
462 
463 	return tipc_group_cong(grp, m->node, m->port, len, &m);
464 }
465 
466 /* tipc_group_sort_msg() - sort msg into queue by bcast sequence number
467  */
468 static void tipc_group_sort_msg(struct sk_buff *skb, struct sk_buff_head *defq)
469 {
470 	struct tipc_msg *_hdr, *hdr = buf_msg(skb);
471 	u16 bc_seqno = msg_grp_bc_seqno(hdr);
472 	struct sk_buff *_skb, *tmp;
473 	int mtyp = msg_type(hdr);
474 
475 	/* Bcast/mcast may be bypassed by ucast or other bcast, - sort it in */
476 	if (mtyp == TIPC_GRP_BCAST_MSG || mtyp == TIPC_GRP_MCAST_MSG) {
477 		skb_queue_walk_safe(defq, _skb, tmp) {
478 			_hdr = buf_msg(_skb);
479 			if (!less(bc_seqno, msg_grp_bc_seqno(_hdr)))
480 				continue;
481 			__skb_queue_before(defq, _skb, skb);
482 			return;
483 		}
484 		/* Bcast was not bypassed, - add to tail */
485 	}
486 	/* Unicasts are never bypassed, - always add to tail */
487 	__skb_queue_tail(defq, skb);
488 }
489 
490 /* tipc_group_filter_msg() - determine if we should accept arriving message
491  */
492 void tipc_group_filter_msg(struct tipc_group *grp, struct sk_buff_head *inputq,
493 			   struct sk_buff_head *xmitq)
494 {
495 	struct sk_buff *skb = __skb_dequeue(inputq);
496 	bool ack, deliver, update, leave = false;
497 	struct sk_buff_head *defq;
498 	struct tipc_member *m;
499 	struct tipc_msg *hdr;
500 	u32 node, port;
501 	int mtyp, blks;
502 
503 	if (!skb)
504 		return;
505 
506 	hdr = buf_msg(skb);
507 	node =  msg_orignode(hdr);
508 	port = msg_origport(hdr);
509 
510 	if (!msg_in_group(hdr))
511 		goto drop;
512 
513 	m = tipc_group_find_member(grp, node, port);
514 	if (!tipc_group_is_sender(m))
515 		goto drop;
516 
517 	if (less(msg_grp_bc_seqno(hdr), m->bc_rcv_nxt))
518 		goto drop;
519 
520 	TIPC_SKB_CB(skb)->orig_member = m->instance;
521 	defq = &m->deferredq;
522 	tipc_group_sort_msg(skb, defq);
523 
524 	while ((skb = skb_peek(defq))) {
525 		hdr = buf_msg(skb);
526 		mtyp = msg_type(hdr);
527 		blks = msg_blocks(hdr);
528 		deliver = true;
529 		ack = false;
530 		update = false;
531 
532 		if (more(msg_grp_bc_seqno(hdr), m->bc_rcv_nxt))
533 			break;
534 
535 		/* Decide what to do with message */
536 		switch (mtyp) {
537 		case TIPC_GRP_MCAST_MSG:
538 			if (msg_nameinst(hdr) != grp->instance) {
539 				update = true;
540 				deliver = false;
541 			}
542 			/* Fall thru */
543 		case TIPC_GRP_BCAST_MSG:
544 			m->bc_rcv_nxt++;
545 			ack = msg_grp_bc_ack_req(hdr);
546 			break;
547 		case TIPC_GRP_UCAST_MSG:
548 			break;
549 		case TIPC_GRP_MEMBER_EVT:
550 			if (m->state == MBR_LEAVING)
551 				leave = true;
552 			if (!grp->events)
553 				deliver = false;
554 			break;
555 		default:
556 			break;
557 		}
558 
559 		/* Execute decisions */
560 		__skb_dequeue(defq);
561 		if (deliver)
562 			__skb_queue_tail(inputq, skb);
563 		else
564 			kfree_skb(skb);
565 
566 		if (ack)
567 			tipc_group_proto_xmit(grp, m, GRP_ACK_MSG, xmitq);
568 
569 		if (leave) {
570 			__skb_queue_purge(defq);
571 			tipc_group_delete_member(grp, m);
572 			break;
573 		}
574 		if (!update)
575 			continue;
576 
577 		tipc_group_update_rcv_win(grp, blks, node, port, xmitq);
578 	}
579 	return;
580 drop:
581 	kfree_skb(skb);
582 }
583 
584 void tipc_group_update_rcv_win(struct tipc_group *grp, int blks, u32 node,
585 			       u32 port, struct sk_buff_head *xmitq)
586 {
587 	struct list_head *active = &grp->active;
588 	int max_active = grp->max_active;
589 	int reclaim_limit = max_active * 3 / 4;
590 	int active_cnt = grp->active_cnt;
591 	struct tipc_member *m, *rm, *pm;
592 
593 	m = tipc_group_find_member(grp, node, port);
594 	if (!m)
595 		return;
596 
597 	m->advertised -= blks;
598 
599 	switch (m->state) {
600 	case MBR_JOINED:
601 		/* First, decide if member can go active */
602 		if (active_cnt <= max_active) {
603 			m->state = MBR_ACTIVE;
604 			list_add_tail(&m->list, active);
605 			grp->active_cnt++;
606 			tipc_group_proto_xmit(grp, m, GRP_ADV_MSG, xmitq);
607 		} else {
608 			m->state = MBR_PENDING;
609 			list_add_tail(&m->list, &grp->pending);
610 		}
611 
612 		if (active_cnt < reclaim_limit)
613 			break;
614 
615 		/* Reclaim from oldest active member, if possible */
616 		if (!list_empty(active)) {
617 			rm = list_first_entry(active, struct tipc_member, list);
618 			rm->state = MBR_RECLAIMING;
619 			list_del_init(&rm->list);
620 			tipc_group_proto_xmit(grp, rm, GRP_RECLAIM_MSG, xmitq);
621 			break;
622 		}
623 		/* Nobody to reclaim from; - revert oldest pending to JOINED */
624 		pm = list_first_entry(&grp->pending, struct tipc_member, list);
625 		list_del_init(&pm->list);
626 		pm->state = MBR_JOINED;
627 		tipc_group_proto_xmit(grp, pm, GRP_ADV_MSG, xmitq);
628 		break;
629 	case MBR_ACTIVE:
630 		if (!list_is_last(&m->list, &grp->active))
631 			list_move_tail(&m->list, &grp->active);
632 		if (m->advertised > (ADV_ACTIVE * 3 / 4))
633 			break;
634 		tipc_group_proto_xmit(grp, m, GRP_ADV_MSG, xmitq);
635 		break;
636 	case MBR_REMITTED:
637 		if (m->advertised > ADV_IDLE)
638 			break;
639 		m->state = MBR_JOINED;
640 		grp->active_cnt--;
641 		if (m->advertised < ADV_IDLE) {
642 			pr_warn_ratelimited("Rcv unexpected msg after REMIT\n");
643 			tipc_group_proto_xmit(grp, m, GRP_ADV_MSG, xmitq);
644 		}
645 
646 		if (list_empty(&grp->pending))
647 			return;
648 
649 		/* Set oldest pending member to active and advertise */
650 		pm = list_first_entry(&grp->pending, struct tipc_member, list);
651 		pm->state = MBR_ACTIVE;
652 		list_move_tail(&pm->list, &grp->active);
653 		grp->active_cnt++;
654 		tipc_group_proto_xmit(grp, pm, GRP_ADV_MSG, xmitq);
655 		break;
656 	case MBR_RECLAIMING:
657 	case MBR_JOINING:
658 	case MBR_LEAVING:
659 	default:
660 		break;
661 	}
662 }
663 
664 static void tipc_group_create_event(struct tipc_group *grp,
665 				    struct tipc_member *m,
666 				    u32 event, u16 seqno,
667 				    struct sk_buff_head *inputq)
668 {	u32 dnode = tipc_own_addr(grp->net);
669 	struct tipc_event evt;
670 	struct sk_buff *skb;
671 	struct tipc_msg *hdr;
672 
673 	evt.event = event;
674 	evt.found_lower = m->instance;
675 	evt.found_upper = m->instance;
676 	evt.port.ref = m->port;
677 	evt.port.node = m->node;
678 	evt.s.seq.type = grp->type;
679 	evt.s.seq.lower = m->instance;
680 	evt.s.seq.upper = m->instance;
681 
682 	skb = tipc_msg_create(TIPC_CRITICAL_IMPORTANCE, TIPC_GRP_MEMBER_EVT,
683 			      GROUP_H_SIZE, sizeof(evt), dnode, m->node,
684 			      grp->portid, m->port, 0);
685 	if (!skb)
686 		return;
687 
688 	hdr = buf_msg(skb);
689 	msg_set_nametype(hdr, grp->type);
690 	msg_set_grp_evt(hdr, event);
691 	msg_set_dest_droppable(hdr, true);
692 	msg_set_grp_bc_seqno(hdr, seqno);
693 	memcpy(msg_data(hdr), &evt, sizeof(evt));
694 	TIPC_SKB_CB(skb)->orig_member = m->instance;
695 	__skb_queue_tail(inputq, skb);
696 }
697 
698 static void tipc_group_proto_xmit(struct tipc_group *grp, struct tipc_member *m,
699 				  int mtyp, struct sk_buff_head *xmitq)
700 {
701 	struct tipc_msg *hdr;
702 	struct sk_buff *skb;
703 	int adv = 0;
704 
705 	skb = tipc_msg_create(GROUP_PROTOCOL, mtyp, INT_H_SIZE, 0,
706 			      m->node, tipc_own_addr(grp->net),
707 			      m->port, grp->portid, 0);
708 	if (!skb)
709 		return;
710 
711 	if (m->state == MBR_ACTIVE)
712 		adv = ADV_ACTIVE - m->advertised;
713 	else if (m->state == MBR_JOINED || m->state == MBR_PENDING)
714 		adv = ADV_IDLE - m->advertised;
715 
716 	hdr = buf_msg(skb);
717 
718 	if (mtyp == GRP_JOIN_MSG) {
719 		msg_set_grp_bc_syncpt(hdr, grp->bc_snd_nxt);
720 		msg_set_adv_win(hdr, adv);
721 		m->advertised += adv;
722 	} else if (mtyp == GRP_LEAVE_MSG) {
723 		msg_set_grp_bc_syncpt(hdr, grp->bc_snd_nxt);
724 	} else if (mtyp == GRP_ADV_MSG) {
725 		msg_set_adv_win(hdr, adv);
726 		m->advertised += adv;
727 	} else if (mtyp == GRP_ACK_MSG) {
728 		msg_set_grp_bc_acked(hdr, m->bc_rcv_nxt);
729 	} else if (mtyp == GRP_REMIT_MSG) {
730 		msg_set_grp_remitted(hdr, m->window);
731 	}
732 	msg_set_dest_droppable(hdr, true);
733 	__skb_queue_tail(xmitq, skb);
734 }
735 
736 void tipc_group_proto_rcv(struct tipc_group *grp, bool *usr_wakeup,
737 			  struct tipc_msg *hdr, struct sk_buff_head *inputq,
738 			  struct sk_buff_head *xmitq)
739 {
740 	u32 node = msg_orignode(hdr);
741 	u32 port = msg_origport(hdr);
742 	struct tipc_member *m, *pm;
743 	u16 remitted, in_flight;
744 
745 	if (!grp)
746 		return;
747 
748 	if (grp->scope == TIPC_NODE_SCOPE && node != tipc_own_addr(grp->net))
749 		return;
750 
751 	m = tipc_group_find_member(grp, node, port);
752 
753 	switch (msg_type(hdr)) {
754 	case GRP_JOIN_MSG:
755 		if (!m)
756 			m = tipc_group_create_member(grp, node, port,
757 						     0, MBR_JOINING);
758 		if (!m)
759 			return;
760 		m->bc_syncpt = msg_grp_bc_syncpt(hdr);
761 		m->bc_rcv_nxt = m->bc_syncpt;
762 		m->window += msg_adv_win(hdr);
763 
764 		/* Wait until PUBLISH event is received if necessary */
765 		if (m->state != MBR_PUBLISHED)
766 			return;
767 
768 		/* Member can be taken into service */
769 		m->state = MBR_JOINED;
770 		tipc_group_open(m, usr_wakeup);
771 		tipc_group_update_member(m, 0);
772 		tipc_group_proto_xmit(grp, m, GRP_ADV_MSG, xmitq);
773 		tipc_group_create_event(grp, m, TIPC_PUBLISHED,
774 					m->bc_syncpt, inputq);
775 		return;
776 	case GRP_LEAVE_MSG:
777 		if (!m)
778 			return;
779 		m->bc_syncpt = msg_grp_bc_syncpt(hdr);
780 		list_del_init(&m->list);
781 		tipc_group_open(m, usr_wakeup);
782 		tipc_group_decr_active(grp, m);
783 		m->state = MBR_LEAVING;
784 		tipc_group_create_event(grp, m, TIPC_WITHDRAWN,
785 					m->bc_syncpt, inputq);
786 		return;
787 	case GRP_ADV_MSG:
788 		if (!m)
789 			return;
790 		m->window += msg_adv_win(hdr);
791 		tipc_group_open(m, usr_wakeup);
792 		return;
793 	case GRP_ACK_MSG:
794 		if (!m)
795 			return;
796 		m->bc_acked = msg_grp_bc_acked(hdr);
797 		if (--grp->bc_ackers)
798 			return;
799 		list_del_init(&m->small_win);
800 		*m->group->open = true;
801 		*usr_wakeup = true;
802 		tipc_group_update_member(m, 0);
803 		return;
804 	case GRP_RECLAIM_MSG:
805 		if (!m)
806 			return;
807 		tipc_group_proto_xmit(grp, m, GRP_REMIT_MSG, xmitq);
808 		m->window = ADV_IDLE;
809 		tipc_group_open(m, usr_wakeup);
810 		return;
811 	case GRP_REMIT_MSG:
812 		if (!m || m->state != MBR_RECLAIMING)
813 			return;
814 
815 		remitted = msg_grp_remitted(hdr);
816 
817 		/* Messages preceding the REMIT still in receive queue */
818 		if (m->advertised > remitted) {
819 			m->state = MBR_REMITTED;
820 			in_flight = m->advertised - remitted;
821 			m->advertised = ADV_IDLE + in_flight;
822 			return;
823 		}
824 		/* This should never happen */
825 		if (m->advertised < remitted)
826 			pr_warn_ratelimited("Unexpected REMIT msg\n");
827 
828 		/* All messages preceding the REMIT have been read */
829 		m->state = MBR_JOINED;
830 		grp->active_cnt--;
831 		m->advertised = ADV_IDLE;
832 
833 		/* Set oldest pending member to active and advertise */
834 		if (list_empty(&grp->pending))
835 			return;
836 		pm = list_first_entry(&grp->pending, struct tipc_member, list);
837 		pm->state = MBR_ACTIVE;
838 		list_move_tail(&pm->list, &grp->active);
839 		grp->active_cnt++;
840 		if (pm->advertised <= (ADV_ACTIVE * 3 / 4))
841 			tipc_group_proto_xmit(grp, pm, GRP_ADV_MSG, xmitq);
842 		return;
843 	default:
844 		pr_warn("Received unknown GROUP_PROTO message\n");
845 	}
846 }
847 
848 /* tipc_group_member_evt() - receive and handle a member up/down event
849  */
850 void tipc_group_member_evt(struct tipc_group *grp,
851 			   bool *usr_wakeup,
852 			   int *sk_rcvbuf,
853 			   struct tipc_msg *hdr,
854 			   struct sk_buff_head *inputq,
855 			   struct sk_buff_head *xmitq)
856 {
857 	struct tipc_event *evt = (void *)msg_data(hdr);
858 	u32 instance = evt->found_lower;
859 	u32 node = evt->port.node;
860 	u32 port = evt->port.ref;
861 	int event = evt->event;
862 	struct tipc_member *m;
863 	struct net *net;
864 	u32 self;
865 
866 	if (!grp)
867 		return;
868 
869 	net = grp->net;
870 	self = tipc_own_addr(net);
871 	if (!grp->loopback && node == self && port == grp->portid)
872 		return;
873 
874 	m = tipc_group_find_member(grp, node, port);
875 
876 	switch (event) {
877 	case TIPC_PUBLISHED:
878 		/* Send and wait for arrival of JOIN message if necessary */
879 		if (!m) {
880 			m = tipc_group_create_member(grp, node, port, instance,
881 						     MBR_PUBLISHED);
882 			if (!m)
883 				break;
884 			tipc_group_update_member(m, 0);
885 			tipc_group_proto_xmit(grp, m, GRP_JOIN_MSG, xmitq);
886 			break;
887 		}
888 
889 		if (m->state != MBR_JOINING)
890 			break;
891 
892 		/* Member can be taken into service */
893 		m->instance = instance;
894 		m->state = MBR_JOINED;
895 		tipc_group_open(m, usr_wakeup);
896 		tipc_group_update_member(m, 0);
897 		tipc_group_proto_xmit(grp, m, GRP_JOIN_MSG, xmitq);
898 		tipc_group_create_event(grp, m, TIPC_PUBLISHED,
899 					m->bc_syncpt, inputq);
900 		break;
901 	case TIPC_WITHDRAWN:
902 		if (!m)
903 			break;
904 
905 		tipc_group_decr_active(grp, m);
906 		m->state = MBR_LEAVING;
907 		list_del_init(&m->list);
908 		tipc_group_open(m, usr_wakeup);
909 
910 		/* Only send event if no LEAVE message can be expected */
911 		if (!tipc_node_is_up(net, node))
912 			tipc_group_create_event(grp, m, TIPC_WITHDRAWN,
913 						m->bc_rcv_nxt, inputq);
914 		break;
915 	default:
916 		break;
917 	}
918 	*sk_rcvbuf = tipc_group_rcvbuf_limit(grp);
919 }
920