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tipc: delay ESTABLISH state event when link is established
[mirror_ubuntu-jammy-kernel.git] / net / tipc / node.c
1 /*
2 * net/tipc/node.c: TIPC node management routines
3 *
4 * Copyright (c) 2000-2006, 2012-2015, Ericsson AB
5 * Copyright (c) 2005-2006, 2010-2014, 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 "link.h"
39 #include "node.h"
40 #include "name_distr.h"
41 #include "socket.h"
42 #include "bcast.h"
43 #include "discover.h"
44
45 /* Node FSM states and events:
46 */
47 enum {
48 SELF_DOWN_PEER_DOWN = 0xdd,
49 SELF_UP_PEER_UP = 0xaa,
50 SELF_DOWN_PEER_LEAVING = 0xd1,
51 SELF_UP_PEER_COMING = 0xac,
52 SELF_COMING_PEER_UP = 0xca,
53 SELF_LEAVING_PEER_DOWN = 0x1d,
54 NODE_FAILINGOVER = 0xf0,
55 NODE_SYNCHING = 0xcc
56 };
57
58 enum {
59 SELF_ESTABL_CONTACT_EVT = 0xece,
60 SELF_LOST_CONTACT_EVT = 0x1ce,
61 PEER_ESTABL_CONTACT_EVT = 0x9ece,
62 PEER_LOST_CONTACT_EVT = 0x91ce,
63 NODE_FAILOVER_BEGIN_EVT = 0xfbe,
64 NODE_FAILOVER_END_EVT = 0xfee,
65 NODE_SYNCH_BEGIN_EVT = 0xcbe,
66 NODE_SYNCH_END_EVT = 0xcee
67 };
68
69 static void __tipc_node_link_down(struct tipc_node *n, int *bearer_id,
70 struct sk_buff_head *xmitq,
71 struct tipc_media_addr **maddr);
72 static void tipc_node_link_down(struct tipc_node *n, int bearer_id,
73 bool delete);
74 static void node_lost_contact(struct tipc_node *n, struct sk_buff_head *inputq);
75 static void node_established_contact(struct tipc_node *n_ptr);
76 static void tipc_node_delete(struct tipc_node *node);
77 static void tipc_node_timeout(unsigned long data);
78 static void tipc_node_fsm_evt(struct tipc_node *n, int evt);
79
80 struct tipc_sock_conn {
81 u32 port;
82 u32 peer_port;
83 u32 peer_node;
84 struct list_head list;
85 };
86
87 static const struct nla_policy tipc_nl_node_policy[TIPC_NLA_NODE_MAX + 1] = {
88 [TIPC_NLA_NODE_UNSPEC] = { .type = NLA_UNSPEC },
89 [TIPC_NLA_NODE_ADDR] = { .type = NLA_U32 },
90 [TIPC_NLA_NODE_UP] = { .type = NLA_FLAG }
91 };
92
93 /*
94 * A trivial power-of-two bitmask technique is used for speed, since this
95 * operation is done for every incoming TIPC packet. The number of hash table
96 * entries has been chosen so that no hash chain exceeds 8 nodes and will
97 * usually be much smaller (typically only a single node).
98 */
99 static unsigned int tipc_hashfn(u32 addr)
100 {
101 return addr & (NODE_HTABLE_SIZE - 1);
102 }
103
104 static void tipc_node_kref_release(struct kref *kref)
105 {
106 struct tipc_node *node = container_of(kref, struct tipc_node, kref);
107
108 tipc_node_delete(node);
109 }
110
111 void tipc_node_put(struct tipc_node *node)
112 {
113 kref_put(&node->kref, tipc_node_kref_release);
114 }
115
116 static void tipc_node_get(struct tipc_node *node)
117 {
118 kref_get(&node->kref);
119 }
120
121 /*
122 * tipc_node_find - locate specified node object, if it exists
123 */
124 struct tipc_node *tipc_node_find(struct net *net, u32 addr)
125 {
126 struct tipc_net *tn = net_generic(net, tipc_net_id);
127 struct tipc_node *node;
128
129 if (unlikely(!in_own_cluster_exact(net, addr)))
130 return NULL;
131
132 rcu_read_lock();
133 hlist_for_each_entry_rcu(node, &tn->node_htable[tipc_hashfn(addr)],
134 hash) {
135 if (node->addr == addr) {
136 tipc_node_get(node);
137 rcu_read_unlock();
138 return node;
139 }
140 }
141 rcu_read_unlock();
142 return NULL;
143 }
144
145 struct tipc_node *tipc_node_create(struct net *net, u32 addr, u16 capabilities)
146 {
147 struct tipc_net *tn = net_generic(net, tipc_net_id);
148 struct tipc_node *n_ptr, *temp_node;
149
150 spin_lock_bh(&tn->node_list_lock);
151 n_ptr = tipc_node_find(net, addr);
152 if (n_ptr)
153 goto exit;
154 n_ptr = kzalloc(sizeof(*n_ptr), GFP_ATOMIC);
155 if (!n_ptr) {
156 pr_warn("Node creation failed, no memory\n");
157 goto exit;
158 }
159 n_ptr->addr = addr;
160 n_ptr->net = net;
161 n_ptr->capabilities = capabilities;
162 kref_init(&n_ptr->kref);
163 spin_lock_init(&n_ptr->lock);
164 INIT_HLIST_NODE(&n_ptr->hash);
165 INIT_LIST_HEAD(&n_ptr->list);
166 INIT_LIST_HEAD(&n_ptr->publ_list);
167 INIT_LIST_HEAD(&n_ptr->conn_sks);
168 skb_queue_head_init(&n_ptr->bclink.namedq);
169 __skb_queue_head_init(&n_ptr->bclink.deferdq);
170 hlist_add_head_rcu(&n_ptr->hash, &tn->node_htable[tipc_hashfn(addr)]);
171 list_for_each_entry_rcu(temp_node, &tn->node_list, list) {
172 if (n_ptr->addr < temp_node->addr)
173 break;
174 }
175 list_add_tail_rcu(&n_ptr->list, &temp_node->list);
176 n_ptr->state = SELF_DOWN_PEER_LEAVING;
177 n_ptr->signature = INVALID_NODE_SIG;
178 n_ptr->active_links[0] = INVALID_BEARER_ID;
179 n_ptr->active_links[1] = INVALID_BEARER_ID;
180 tipc_node_get(n_ptr);
181 setup_timer(&n_ptr->timer, tipc_node_timeout, (unsigned long)n_ptr);
182 n_ptr->keepalive_intv = U32_MAX;
183 exit:
184 spin_unlock_bh(&tn->node_list_lock);
185 return n_ptr;
186 }
187
188 static void tipc_node_calculate_timer(struct tipc_node *n, struct tipc_link *l)
189 {
190 unsigned long tol = l->tolerance;
191 unsigned long intv = ((tol / 4) > 500) ? 500 : tol / 4;
192 unsigned long keepalive_intv = msecs_to_jiffies(intv);
193
194 /* Link with lowest tolerance determines timer interval */
195 if (keepalive_intv < n->keepalive_intv)
196 n->keepalive_intv = keepalive_intv;
197
198 /* Ensure link's abort limit corresponds to current interval */
199 l->abort_limit = l->tolerance / jiffies_to_msecs(n->keepalive_intv);
200 }
201
202 static void tipc_node_delete(struct tipc_node *node)
203 {
204 list_del_rcu(&node->list);
205 hlist_del_rcu(&node->hash);
206 kfree_rcu(node, rcu);
207 }
208
209 void tipc_node_stop(struct net *net)
210 {
211 struct tipc_net *tn = net_generic(net, tipc_net_id);
212 struct tipc_node *node, *t_node;
213
214 spin_lock_bh(&tn->node_list_lock);
215 list_for_each_entry_safe(node, t_node, &tn->node_list, list) {
216 if (del_timer(&node->timer))
217 tipc_node_put(node);
218 tipc_node_put(node);
219 }
220 spin_unlock_bh(&tn->node_list_lock);
221 }
222
223 int tipc_node_add_conn(struct net *net, u32 dnode, u32 port, u32 peer_port)
224 {
225 struct tipc_node *node;
226 struct tipc_sock_conn *conn;
227 int err = 0;
228
229 if (in_own_node(net, dnode))
230 return 0;
231
232 node = tipc_node_find(net, dnode);
233 if (!node) {
234 pr_warn("Connecting sock to node 0x%x failed\n", dnode);
235 return -EHOSTUNREACH;
236 }
237 conn = kmalloc(sizeof(*conn), GFP_ATOMIC);
238 if (!conn) {
239 err = -EHOSTUNREACH;
240 goto exit;
241 }
242 conn->peer_node = dnode;
243 conn->port = port;
244 conn->peer_port = peer_port;
245
246 tipc_node_lock(node);
247 list_add_tail(&conn->list, &node->conn_sks);
248 tipc_node_unlock(node);
249 exit:
250 tipc_node_put(node);
251 return err;
252 }
253
254 void tipc_node_remove_conn(struct net *net, u32 dnode, u32 port)
255 {
256 struct tipc_node *node;
257 struct tipc_sock_conn *conn, *safe;
258
259 if (in_own_node(net, dnode))
260 return;
261
262 node = tipc_node_find(net, dnode);
263 if (!node)
264 return;
265
266 tipc_node_lock(node);
267 list_for_each_entry_safe(conn, safe, &node->conn_sks, list) {
268 if (port != conn->port)
269 continue;
270 list_del(&conn->list);
271 kfree(conn);
272 }
273 tipc_node_unlock(node);
274 tipc_node_put(node);
275 }
276
277 /* tipc_node_timeout - handle expiration of node timer
278 */
279 static void tipc_node_timeout(unsigned long data)
280 {
281 struct tipc_node *n = (struct tipc_node *)data;
282 struct tipc_link_entry *le;
283 struct sk_buff_head xmitq;
284 int bearer_id;
285 int rc = 0;
286
287 __skb_queue_head_init(&xmitq);
288
289 for (bearer_id = 0; bearer_id < MAX_BEARERS; bearer_id++) {
290 tipc_node_lock(n);
291 le = &n->links[bearer_id];
292 if (le->link) {
293 /* Link tolerance may change asynchronously: */
294 tipc_node_calculate_timer(n, le->link);
295 rc = tipc_link_timeout(le->link, &xmitq);
296 }
297 tipc_node_unlock(n);
298 tipc_bearer_xmit(n->net, bearer_id, &xmitq, &le->maddr);
299 if (rc & TIPC_LINK_DOWN_EVT)
300 tipc_node_link_down(n, bearer_id, false);
301 }
302 if (!mod_timer(&n->timer, jiffies + n->keepalive_intv))
303 tipc_node_get(n);
304 tipc_node_put(n);
305 }
306
307 /**
308 * __tipc_node_link_up - handle addition of link
309 * Node lock must be held by caller
310 * Link becomes active (alone or shared) or standby, depending on its priority.
311 */
312 static void __tipc_node_link_up(struct tipc_node *n, int bearer_id,
313 struct sk_buff_head *xmitq)
314 {
315 int *slot0 = &n->active_links[0];
316 int *slot1 = &n->active_links[1];
317 struct tipc_link *ol = node_active_link(n, 0);
318 struct tipc_link *nl = n->links[bearer_id].link;
319
320 if (!nl)
321 return;
322
323 tipc_link_fsm_evt(nl, LINK_ESTABLISH_EVT);
324 if (!tipc_link_is_up(nl))
325 return;
326
327 n->working_links++;
328 n->action_flags |= TIPC_NOTIFY_LINK_UP;
329 n->link_id = nl->peer_bearer_id << 16 | bearer_id;
330
331 /* Leave room for tunnel header when returning 'mtu' to users: */
332 n->links[bearer_id].mtu = nl->mtu - INT_H_SIZE;
333
334 tipc_bearer_add_dest(n->net, bearer_id, n->addr);
335
336 pr_debug("Established link <%s> on network plane %c\n",
337 nl->name, nl->net_plane);
338
339 /* First link? => give it both slots */
340 if (!ol) {
341 *slot0 = bearer_id;
342 *slot1 = bearer_id;
343 tipc_link_build_bcast_sync_msg(nl, xmitq);
344 node_established_contact(n);
345 return;
346 }
347
348 /* Second link => redistribute slots */
349 if (nl->priority > ol->priority) {
350 pr_debug("Old link <%s> becomes standby\n", ol->name);
351 *slot0 = bearer_id;
352 *slot1 = bearer_id;
353 } else if (nl->priority == ol->priority) {
354 *slot0 = bearer_id;
355 } else {
356 pr_debug("New link <%s> is standby\n", nl->name);
357 }
358
359 /* Prepare synchronization with first link */
360 tipc_link_tnl_prepare(ol, nl, SYNCH_MSG, xmitq);
361 }
362
363 /**
364 * tipc_node_link_up - handle addition of link
365 *
366 * Link becomes active (alone or shared) or standby, depending on its priority.
367 */
368 static void tipc_node_link_up(struct tipc_node *n, int bearer_id,
369 struct sk_buff_head *xmitq)
370 {
371 tipc_node_lock(n);
372 __tipc_node_link_up(n, bearer_id, xmitq);
373 tipc_node_unlock(n);
374 }
375
376 /**
377 * __tipc_node_link_down - handle loss of link
378 */
379 static void __tipc_node_link_down(struct tipc_node *n, int *bearer_id,
380 struct sk_buff_head *xmitq,
381 struct tipc_media_addr **maddr)
382 {
383 struct tipc_link_entry *le = &n->links[*bearer_id];
384 int *slot0 = &n->active_links[0];
385 int *slot1 = &n->active_links[1];
386 int i, highest = 0;
387 struct tipc_link *l, *_l, *tnl;
388
389 l = n->links[*bearer_id].link;
390 if (!l || tipc_link_is_reset(l))
391 return;
392
393 n->working_links--;
394 n->action_flags |= TIPC_NOTIFY_LINK_DOWN;
395 n->link_id = l->peer_bearer_id << 16 | *bearer_id;
396
397 tipc_bearer_remove_dest(n->net, *bearer_id, n->addr);
398
399 pr_debug("Lost link <%s> on network plane %c\n",
400 l->name, l->net_plane);
401
402 /* Select new active link if any available */
403 *slot0 = INVALID_BEARER_ID;
404 *slot1 = INVALID_BEARER_ID;
405 for (i = 0; i < MAX_BEARERS; i++) {
406 _l = n->links[i].link;
407 if (!_l || !tipc_link_is_up(_l))
408 continue;
409 if (_l == l)
410 continue;
411 if (_l->priority < highest)
412 continue;
413 if (_l->priority > highest) {
414 highest = _l->priority;
415 *slot0 = i;
416 *slot1 = i;
417 continue;
418 }
419 *slot1 = i;
420 }
421
422 if (!tipc_node_is_up(n)) {
423 tipc_link_reset(l);
424 node_lost_contact(n, &le->inputq);
425 return;
426 }
427
428 /* There is still a working link => initiate failover */
429 tnl = node_active_link(n, 0);
430 tipc_link_fsm_evt(tnl, LINK_SYNCH_END_EVT);
431 tipc_node_fsm_evt(n, NODE_SYNCH_END_EVT);
432 n->sync_point = tnl->rcv_nxt + (U16_MAX / 2 - 1);
433 tipc_link_tnl_prepare(l, tnl, FAILOVER_MSG, xmitq);
434 tipc_link_reset(l);
435 tipc_link_fsm_evt(l, LINK_FAILOVER_BEGIN_EVT);
436 tipc_node_fsm_evt(n, NODE_FAILOVER_BEGIN_EVT);
437 *maddr = &n->links[tnl->bearer_id].maddr;
438 *bearer_id = tnl->bearer_id;
439 }
440
441 static void tipc_node_link_down(struct tipc_node *n, int bearer_id, bool delete)
442 {
443 struct tipc_link_entry *le = &n->links[bearer_id];
444 struct tipc_link *l = le->link;
445 struct tipc_media_addr *maddr;
446 struct sk_buff_head xmitq;
447
448 if (!l)
449 return;
450
451 __skb_queue_head_init(&xmitq);
452
453 tipc_node_lock(n);
454 if (!tipc_link_is_establishing(l)) {
455 __tipc_node_link_down(n, &bearer_id, &xmitq, &maddr);
456 if (delete) {
457 kfree(l);
458 le->link = NULL;
459 n->link_cnt--;
460 }
461 } else {
462 /* Defuse pending tipc_node_link_up() */
463 tipc_link_fsm_evt(l, LINK_RESET_EVT);
464 }
465 tipc_node_unlock(n);
466
467 tipc_bearer_xmit(n->net, bearer_id, &xmitq, maddr);
468 tipc_sk_rcv(n->net, &le->inputq);
469 }
470
471 bool tipc_node_is_up(struct tipc_node *n)
472 {
473 return n->active_links[0] != INVALID_BEARER_ID;
474 }
475
476 void tipc_node_check_dest(struct net *net, u32 onode,
477 struct tipc_bearer *b,
478 u16 capabilities, u32 signature,
479 struct tipc_media_addr *maddr,
480 bool *respond, bool *dupl_addr)
481 {
482 struct tipc_node *n;
483 struct tipc_link *l;
484 struct tipc_link_entry *le;
485 bool addr_match = false;
486 bool sign_match = false;
487 bool link_up = false;
488 bool accept_addr = false;
489 bool reset = true;
490
491 *dupl_addr = false;
492 *respond = false;
493
494 n = tipc_node_create(net, onode, capabilities);
495 if (!n)
496 return;
497
498 tipc_node_lock(n);
499
500 le = &n->links[b->identity];
501
502 /* Prepare to validate requesting node's signature and media address */
503 l = le->link;
504 link_up = l && tipc_link_is_up(l);
505 addr_match = l && !memcmp(&le->maddr, maddr, sizeof(*maddr));
506 sign_match = (signature == n->signature);
507
508 /* These three flags give us eight permutations: */
509
510 if (sign_match && addr_match && link_up) {
511 /* All is fine. Do nothing. */
512 reset = false;
513 } else if (sign_match && addr_match && !link_up) {
514 /* Respond. The link will come up in due time */
515 *respond = true;
516 } else if (sign_match && !addr_match && link_up) {
517 /* Peer has changed i/f address without rebooting.
518 * If so, the link will reset soon, and the next
519 * discovery will be accepted. So we can ignore it.
520 * It may also be an cloned or malicious peer having
521 * chosen the same node address and signature as an
522 * existing one.
523 * Ignore requests until the link goes down, if ever.
524 */
525 *dupl_addr = true;
526 } else if (sign_match && !addr_match && !link_up) {
527 /* Peer link has changed i/f address without rebooting.
528 * It may also be a cloned or malicious peer; we can't
529 * distinguish between the two.
530 * The signature is correct, so we must accept.
531 */
532 accept_addr = true;
533 *respond = true;
534 } else if (!sign_match && addr_match && link_up) {
535 /* Peer node rebooted. Two possibilities:
536 * - Delayed re-discovery; this link endpoint has already
537 * reset and re-established contact with the peer, before
538 * receiving a discovery message from that node.
539 * (The peer happened to receive one from this node first).
540 * - The peer came back so fast that our side has not
541 * discovered it yet. Probing from this side will soon
542 * reset the link, since there can be no working link
543 * endpoint at the peer end, and the link will re-establish.
544 * Accept the signature, since it comes from a known peer.
545 */
546 n->signature = signature;
547 } else if (!sign_match && addr_match && !link_up) {
548 /* The peer node has rebooted.
549 * Accept signature, since it is a known peer.
550 */
551 n->signature = signature;
552 *respond = true;
553 } else if (!sign_match && !addr_match && link_up) {
554 /* Peer rebooted with new address, or a new/duplicate peer.
555 * Ignore until the link goes down, if ever.
556 */
557 *dupl_addr = true;
558 } else if (!sign_match && !addr_match && !link_up) {
559 /* Peer rebooted with new address, or it is a new peer.
560 * Accept signature and address.
561 */
562 n->signature = signature;
563 accept_addr = true;
564 *respond = true;
565 }
566
567 if (!accept_addr)
568 goto exit;
569
570 /* Now create new link if not already existing */
571 if (!l) {
572 if (n->link_cnt == 2) {
573 pr_warn("Cannot establish 3rd link to %x\n", n->addr);
574 goto exit;
575 }
576 if (!tipc_link_create(n, b, mod(tipc_net(net)->random),
577 tipc_own_addr(net), onode, &le->maddr,
578 &le->inputq, &n->bclink.namedq, &l)) {
579 *respond = false;
580 goto exit;
581 }
582 tipc_link_reset(l);
583 if (n->state == NODE_FAILINGOVER)
584 tipc_link_fsm_evt(l, LINK_FAILOVER_BEGIN_EVT);
585 le->link = l;
586 n->link_cnt++;
587 tipc_node_calculate_timer(n, l);
588 if (n->link_cnt == 1)
589 if (!mod_timer(&n->timer, jiffies + n->keepalive_intv))
590 tipc_node_get(n);
591 }
592 memcpy(&le->maddr, maddr, sizeof(*maddr));
593 exit:
594 tipc_node_unlock(n);
595 if (reset && !tipc_link_is_reset(l))
596 tipc_node_link_down(n, b->identity, false);
597 tipc_node_put(n);
598 }
599
600 void tipc_node_delete_links(struct net *net, int bearer_id)
601 {
602 struct tipc_net *tn = net_generic(net, tipc_net_id);
603 struct tipc_node *n;
604
605 rcu_read_lock();
606 list_for_each_entry_rcu(n, &tn->node_list, list) {
607 tipc_node_link_down(n, bearer_id, true);
608 }
609 rcu_read_unlock();
610 }
611
612 static void tipc_node_reset_links(struct tipc_node *n)
613 {
614 char addr_string[16];
615 int i;
616
617 pr_warn("Resetting all links to %s\n",
618 tipc_addr_string_fill(addr_string, n->addr));
619
620 for (i = 0; i < MAX_BEARERS; i++) {
621 tipc_node_link_down(n, i, false);
622 }
623 }
624
625 /* tipc_node_fsm_evt - node finite state machine
626 * Determines when contact is allowed with peer node
627 */
628 static void tipc_node_fsm_evt(struct tipc_node *n, int evt)
629 {
630 int state = n->state;
631
632 switch (state) {
633 case SELF_DOWN_PEER_DOWN:
634 switch (evt) {
635 case SELF_ESTABL_CONTACT_EVT:
636 state = SELF_UP_PEER_COMING;
637 break;
638 case PEER_ESTABL_CONTACT_EVT:
639 state = SELF_COMING_PEER_UP;
640 break;
641 case SELF_LOST_CONTACT_EVT:
642 case PEER_LOST_CONTACT_EVT:
643 break;
644 case NODE_SYNCH_END_EVT:
645 case NODE_SYNCH_BEGIN_EVT:
646 case NODE_FAILOVER_BEGIN_EVT:
647 case NODE_FAILOVER_END_EVT:
648 default:
649 goto illegal_evt;
650 }
651 break;
652 case SELF_UP_PEER_UP:
653 switch (evt) {
654 case SELF_LOST_CONTACT_EVT:
655 state = SELF_DOWN_PEER_LEAVING;
656 break;
657 case PEER_LOST_CONTACT_EVT:
658 state = SELF_LEAVING_PEER_DOWN;
659 break;
660 case NODE_SYNCH_BEGIN_EVT:
661 state = NODE_SYNCHING;
662 break;
663 case NODE_FAILOVER_BEGIN_EVT:
664 state = NODE_FAILINGOVER;
665 break;
666 case SELF_ESTABL_CONTACT_EVT:
667 case PEER_ESTABL_CONTACT_EVT:
668 case NODE_SYNCH_END_EVT:
669 case NODE_FAILOVER_END_EVT:
670 break;
671 default:
672 goto illegal_evt;
673 }
674 break;
675 case SELF_DOWN_PEER_LEAVING:
676 switch (evt) {
677 case PEER_LOST_CONTACT_EVT:
678 state = SELF_DOWN_PEER_DOWN;
679 break;
680 case SELF_ESTABL_CONTACT_EVT:
681 case PEER_ESTABL_CONTACT_EVT:
682 case SELF_LOST_CONTACT_EVT:
683 break;
684 case NODE_SYNCH_END_EVT:
685 case NODE_SYNCH_BEGIN_EVT:
686 case NODE_FAILOVER_BEGIN_EVT:
687 case NODE_FAILOVER_END_EVT:
688 default:
689 goto illegal_evt;
690 }
691 break;
692 case SELF_UP_PEER_COMING:
693 switch (evt) {
694 case PEER_ESTABL_CONTACT_EVT:
695 state = SELF_UP_PEER_UP;
696 break;
697 case SELF_LOST_CONTACT_EVT:
698 state = SELF_DOWN_PEER_LEAVING;
699 break;
700 case SELF_ESTABL_CONTACT_EVT:
701 case PEER_LOST_CONTACT_EVT:
702 case NODE_SYNCH_END_EVT:
703 case NODE_FAILOVER_BEGIN_EVT:
704 break;
705 case NODE_SYNCH_BEGIN_EVT:
706 case NODE_FAILOVER_END_EVT:
707 default:
708 goto illegal_evt;
709 }
710 break;
711 case SELF_COMING_PEER_UP:
712 switch (evt) {
713 case SELF_ESTABL_CONTACT_EVT:
714 state = SELF_UP_PEER_UP;
715 break;
716 case PEER_LOST_CONTACT_EVT:
717 state = SELF_LEAVING_PEER_DOWN;
718 break;
719 case SELF_LOST_CONTACT_EVT:
720 case PEER_ESTABL_CONTACT_EVT:
721 break;
722 case NODE_SYNCH_END_EVT:
723 case NODE_SYNCH_BEGIN_EVT:
724 case NODE_FAILOVER_BEGIN_EVT:
725 case NODE_FAILOVER_END_EVT:
726 default:
727 goto illegal_evt;
728 }
729 break;
730 case SELF_LEAVING_PEER_DOWN:
731 switch (evt) {
732 case SELF_LOST_CONTACT_EVT:
733 state = SELF_DOWN_PEER_DOWN;
734 break;
735 case SELF_ESTABL_CONTACT_EVT:
736 case PEER_ESTABL_CONTACT_EVT:
737 case PEER_LOST_CONTACT_EVT:
738 break;
739 case NODE_SYNCH_END_EVT:
740 case NODE_SYNCH_BEGIN_EVT:
741 case NODE_FAILOVER_BEGIN_EVT:
742 case NODE_FAILOVER_END_EVT:
743 default:
744 goto illegal_evt;
745 }
746 break;
747 case NODE_FAILINGOVER:
748 switch (evt) {
749 case SELF_LOST_CONTACT_EVT:
750 state = SELF_DOWN_PEER_LEAVING;
751 break;
752 case PEER_LOST_CONTACT_EVT:
753 state = SELF_LEAVING_PEER_DOWN;
754 break;
755 case NODE_FAILOVER_END_EVT:
756 state = SELF_UP_PEER_UP;
757 break;
758 case NODE_FAILOVER_BEGIN_EVT:
759 case SELF_ESTABL_CONTACT_EVT:
760 case PEER_ESTABL_CONTACT_EVT:
761 break;
762 case NODE_SYNCH_BEGIN_EVT:
763 case NODE_SYNCH_END_EVT:
764 default:
765 goto illegal_evt;
766 }
767 break;
768 case NODE_SYNCHING:
769 switch (evt) {
770 case SELF_LOST_CONTACT_EVT:
771 state = SELF_DOWN_PEER_LEAVING;
772 break;
773 case PEER_LOST_CONTACT_EVT:
774 state = SELF_LEAVING_PEER_DOWN;
775 break;
776 case NODE_SYNCH_END_EVT:
777 state = SELF_UP_PEER_UP;
778 break;
779 case NODE_FAILOVER_BEGIN_EVT:
780 state = NODE_FAILINGOVER;
781 break;
782 case NODE_SYNCH_BEGIN_EVT:
783 case SELF_ESTABL_CONTACT_EVT:
784 case PEER_ESTABL_CONTACT_EVT:
785 break;
786 case NODE_FAILOVER_END_EVT:
787 default:
788 goto illegal_evt;
789 }
790 break;
791 default:
792 pr_err("Unknown node fsm state %x\n", state);
793 break;
794 }
795 n->state = state;
796 return;
797
798 illegal_evt:
799 pr_err("Illegal node fsm evt %x in state %x\n", evt, state);
800 }
801
802 bool tipc_node_filter_pkt(struct tipc_node *n, struct tipc_msg *hdr)
803 {
804 int state = n->state;
805
806 if (likely(state == SELF_UP_PEER_UP))
807 return true;
808
809 if (state == SELF_LEAVING_PEER_DOWN)
810 return false;
811
812 if (state == SELF_DOWN_PEER_LEAVING) {
813 if (msg_peer_node_is_up(hdr))
814 return false;
815 }
816
817 return true;
818 }
819
820 static void node_established_contact(struct tipc_node *n_ptr)
821 {
822 tipc_node_fsm_evt(n_ptr, SELF_ESTABL_CONTACT_EVT);
823 n_ptr->action_flags |= TIPC_NOTIFY_NODE_UP;
824 n_ptr->bclink.oos_state = 0;
825 n_ptr->bclink.acked = tipc_bclink_get_last_sent(n_ptr->net);
826 tipc_bclink_add_node(n_ptr->net, n_ptr->addr);
827 }
828
829 static void node_lost_contact(struct tipc_node *n_ptr,
830 struct sk_buff_head *inputq)
831 {
832 char addr_string[16];
833 struct tipc_sock_conn *conn, *safe;
834 struct tipc_link *l;
835 struct list_head *conns = &n_ptr->conn_sks;
836 struct sk_buff *skb;
837 struct tipc_net *tn = net_generic(n_ptr->net, tipc_net_id);
838 uint i;
839
840 pr_debug("Lost contact with %s\n",
841 tipc_addr_string_fill(addr_string, n_ptr->addr));
842
843 /* Flush broadcast link info associated with lost node */
844 if (n_ptr->bclink.recv_permitted) {
845 __skb_queue_purge(&n_ptr->bclink.deferdq);
846
847 if (n_ptr->bclink.reasm_buf) {
848 kfree_skb(n_ptr->bclink.reasm_buf);
849 n_ptr->bclink.reasm_buf = NULL;
850 }
851
852 tipc_bclink_remove_node(n_ptr->net, n_ptr->addr);
853 tipc_bclink_acknowledge(n_ptr, INVALID_LINK_SEQ);
854
855 n_ptr->bclink.recv_permitted = false;
856 }
857
858 /* Abort any ongoing link failover */
859 for (i = 0; i < MAX_BEARERS; i++) {
860 l = n_ptr->links[i].link;
861 if (l)
862 tipc_link_fsm_evt(l, LINK_FAILOVER_END_EVT);
863 }
864
865 /* Prevent re-contact with node until cleanup is done */
866 tipc_node_fsm_evt(n_ptr, SELF_LOST_CONTACT_EVT);
867
868 /* Notify publications from this node */
869 n_ptr->action_flags |= TIPC_NOTIFY_NODE_DOWN;
870
871 /* Notify sockets connected to node */
872 list_for_each_entry_safe(conn, safe, conns, list) {
873 skb = tipc_msg_create(TIPC_CRITICAL_IMPORTANCE, TIPC_CONN_MSG,
874 SHORT_H_SIZE, 0, tn->own_addr,
875 conn->peer_node, conn->port,
876 conn->peer_port, TIPC_ERR_NO_NODE);
877 if (likely(skb))
878 skb_queue_tail(inputq, skb);
879 list_del(&conn->list);
880 kfree(conn);
881 }
882 }
883
884 /**
885 * tipc_node_get_linkname - get the name of a link
886 *
887 * @bearer_id: id of the bearer
888 * @node: peer node address
889 * @linkname: link name output buffer
890 *
891 * Returns 0 on success
892 */
893 int tipc_node_get_linkname(struct net *net, u32 bearer_id, u32 addr,
894 char *linkname, size_t len)
895 {
896 struct tipc_link *link;
897 int err = -EINVAL;
898 struct tipc_node *node = tipc_node_find(net, addr);
899
900 if (!node)
901 return err;
902
903 if (bearer_id >= MAX_BEARERS)
904 goto exit;
905
906 tipc_node_lock(node);
907 link = node->links[bearer_id].link;
908 if (link) {
909 strncpy(linkname, link->name, len);
910 err = 0;
911 }
912 exit:
913 tipc_node_unlock(node);
914 tipc_node_put(node);
915 return err;
916 }
917
918 void tipc_node_unlock(struct tipc_node *node)
919 {
920 struct net *net = node->net;
921 u32 addr = 0;
922 u32 flags = node->action_flags;
923 u32 link_id = 0;
924 struct list_head *publ_list;
925
926 if (likely(!flags)) {
927 spin_unlock_bh(&node->lock);
928 return;
929 }
930
931 addr = node->addr;
932 link_id = node->link_id;
933 publ_list = &node->publ_list;
934
935 node->action_flags &= ~(TIPC_NOTIFY_NODE_DOWN | TIPC_NOTIFY_NODE_UP |
936 TIPC_NOTIFY_LINK_DOWN | TIPC_NOTIFY_LINK_UP |
937 TIPC_WAKEUP_BCAST_USERS | TIPC_BCAST_MSG_EVT |
938 TIPC_BCAST_RESET);
939
940 spin_unlock_bh(&node->lock);
941
942 if (flags & TIPC_NOTIFY_NODE_DOWN)
943 tipc_publ_notify(net, publ_list, addr);
944
945 if (flags & TIPC_WAKEUP_BCAST_USERS)
946 tipc_bclink_wakeup_users(net);
947
948 if (flags & TIPC_NOTIFY_NODE_UP)
949 tipc_named_node_up(net, addr);
950
951 if (flags & TIPC_NOTIFY_LINK_UP)
952 tipc_nametbl_publish(net, TIPC_LINK_STATE, addr, addr,
953 TIPC_NODE_SCOPE, link_id, addr);
954
955 if (flags & TIPC_NOTIFY_LINK_DOWN)
956 tipc_nametbl_withdraw(net, TIPC_LINK_STATE, addr,
957 link_id, addr);
958
959 if (flags & TIPC_BCAST_MSG_EVT)
960 tipc_bclink_input(net);
961
962 if (flags & TIPC_BCAST_RESET)
963 tipc_node_reset_links(node);
964 }
965
966 /* Caller should hold node lock for the passed node */
967 static int __tipc_nl_add_node(struct tipc_nl_msg *msg, struct tipc_node *node)
968 {
969 void *hdr;
970 struct nlattr *attrs;
971
972 hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
973 NLM_F_MULTI, TIPC_NL_NODE_GET);
974 if (!hdr)
975 return -EMSGSIZE;
976
977 attrs = nla_nest_start(msg->skb, TIPC_NLA_NODE);
978 if (!attrs)
979 goto msg_full;
980
981 if (nla_put_u32(msg->skb, TIPC_NLA_NODE_ADDR, node->addr))
982 goto attr_msg_full;
983 if (tipc_node_is_up(node))
984 if (nla_put_flag(msg->skb, TIPC_NLA_NODE_UP))
985 goto attr_msg_full;
986
987 nla_nest_end(msg->skb, attrs);
988 genlmsg_end(msg->skb, hdr);
989
990 return 0;
991
992 attr_msg_full:
993 nla_nest_cancel(msg->skb, attrs);
994 msg_full:
995 genlmsg_cancel(msg->skb, hdr);
996
997 return -EMSGSIZE;
998 }
999
1000 static struct tipc_link *tipc_node_select_link(struct tipc_node *n, int sel,
1001 int *bearer_id,
1002 struct tipc_media_addr **maddr)
1003 {
1004 int id = n->active_links[sel & 1];
1005
1006 if (unlikely(id < 0))
1007 return NULL;
1008
1009 *bearer_id = id;
1010 *maddr = &n->links[id].maddr;
1011 return n->links[id].link;
1012 }
1013
1014 /**
1015 * tipc_node_xmit() is the general link level function for message sending
1016 * @net: the applicable net namespace
1017 * @list: chain of buffers containing message
1018 * @dnode: address of destination node
1019 * @selector: a number used for deterministic link selection
1020 * Consumes the buffer chain, except when returning -ELINKCONG
1021 * Returns 0 if success, otherwise errno: -ELINKCONG,-EHOSTUNREACH,-EMSGSIZE
1022 */
1023 int tipc_node_xmit(struct net *net, struct sk_buff_head *list,
1024 u32 dnode, int selector)
1025 {
1026 struct tipc_link *l = NULL;
1027 struct tipc_node *n;
1028 struct sk_buff_head xmitq;
1029 struct tipc_media_addr *maddr;
1030 int bearer_id;
1031 int rc = -EHOSTUNREACH;
1032
1033 __skb_queue_head_init(&xmitq);
1034 n = tipc_node_find(net, dnode);
1035 if (likely(n)) {
1036 tipc_node_lock(n);
1037 l = tipc_node_select_link(n, selector, &bearer_id, &maddr);
1038 if (likely(l))
1039 rc = tipc_link_xmit(l, list, &xmitq);
1040 tipc_node_unlock(n);
1041 if (unlikely(rc == -ENOBUFS))
1042 tipc_node_link_down(n, bearer_id, false);
1043 tipc_node_put(n);
1044 }
1045 if (likely(!rc)) {
1046 tipc_bearer_xmit(net, bearer_id, &xmitq, maddr);
1047 return 0;
1048 }
1049 if (likely(in_own_node(net, dnode))) {
1050 tipc_sk_rcv(net, list);
1051 return 0;
1052 }
1053 return rc;
1054 }
1055
1056 /* tipc_node_xmit_skb(): send single buffer to destination
1057 * Buffers sent via this functon are generally TIPC_SYSTEM_IMPORTANCE
1058 * messages, which will not be rejected
1059 * The only exception is datagram messages rerouted after secondary
1060 * lookup, which are rare and safe to dispose of anyway.
1061 * TODO: Return real return value, and let callers use
1062 * tipc_wait_for_sendpkt() where applicable
1063 */
1064 int tipc_node_xmit_skb(struct net *net, struct sk_buff *skb, u32 dnode,
1065 u32 selector)
1066 {
1067 struct sk_buff_head head;
1068 int rc;
1069
1070 skb_queue_head_init(&head);
1071 __skb_queue_tail(&head, skb);
1072 rc = tipc_node_xmit(net, &head, dnode, selector);
1073 if (rc == -ELINKCONG)
1074 kfree_skb(skb);
1075 return 0;
1076 }
1077
1078 /**
1079 * tipc_node_check_state - check and if necessary update node state
1080 * @skb: TIPC packet
1081 * @bearer_id: identity of bearer delivering the packet
1082 * Returns true if state is ok, otherwise consumes buffer and returns false
1083 */
1084 static bool tipc_node_check_state(struct tipc_node *n, struct sk_buff *skb,
1085 int bearer_id, struct sk_buff_head *xmitq)
1086 {
1087 struct tipc_msg *hdr = buf_msg(skb);
1088 int usr = msg_user(hdr);
1089 int mtyp = msg_type(hdr);
1090 u16 oseqno = msg_seqno(hdr);
1091 u16 iseqno = msg_seqno(msg_get_wrapped(hdr));
1092 u16 exp_pkts = msg_msgcnt(hdr);
1093 u16 rcv_nxt, syncpt, dlv_nxt;
1094 int state = n->state;
1095 struct tipc_link *l, *tnl, *pl = NULL;
1096 struct tipc_media_addr *maddr;
1097 int i, pb_id;
1098
1099 l = n->links[bearer_id].link;
1100 if (!l)
1101 return false;
1102 rcv_nxt = l->rcv_nxt;
1103
1104
1105 if (likely((state == SELF_UP_PEER_UP) && (usr != TUNNEL_PROTOCOL)))
1106 return true;
1107
1108 /* Find parallel link, if any */
1109 for (i = 0; i < MAX_BEARERS; i++) {
1110 if ((i != bearer_id) && n->links[i].link) {
1111 pl = n->links[i].link;
1112 break;
1113 }
1114 }
1115
1116 /* Update node accesibility if applicable */
1117 if (state == SELF_UP_PEER_COMING) {
1118 if (!tipc_link_is_up(l))
1119 return true;
1120 if (!msg_peer_link_is_up(hdr))
1121 return true;
1122 tipc_node_fsm_evt(n, PEER_ESTABL_CONTACT_EVT);
1123 }
1124
1125 if (state == SELF_DOWN_PEER_LEAVING) {
1126 if (msg_peer_node_is_up(hdr))
1127 return false;
1128 tipc_node_fsm_evt(n, PEER_LOST_CONTACT_EVT);
1129 }
1130
1131 /* Ignore duplicate packets */
1132 if (less(oseqno, rcv_nxt))
1133 return true;
1134
1135 /* Initiate or update failover mode if applicable */
1136 if ((usr == TUNNEL_PROTOCOL) && (mtyp == FAILOVER_MSG)) {
1137 syncpt = oseqno + exp_pkts - 1;
1138 if (pl && tipc_link_is_up(pl)) {
1139 pb_id = pl->bearer_id;
1140 __tipc_node_link_down(n, &pb_id, xmitq, &maddr);
1141 tipc_skb_queue_splice_tail_init(pl->inputq, l->inputq);
1142 }
1143 /* If pkts arrive out of order, use lowest calculated syncpt */
1144 if (less(syncpt, n->sync_point))
1145 n->sync_point = syncpt;
1146 }
1147
1148 /* Open parallel link when tunnel link reaches synch point */
1149 if ((n->state == NODE_FAILINGOVER) && tipc_link_is_up(l)) {
1150 if (!more(rcv_nxt, n->sync_point))
1151 return true;
1152 tipc_node_fsm_evt(n, NODE_FAILOVER_END_EVT);
1153 if (pl)
1154 tipc_link_fsm_evt(pl, LINK_FAILOVER_END_EVT);
1155 return true;
1156 }
1157
1158 /* No synching needed if only one link */
1159 if (!pl || !tipc_link_is_up(pl))
1160 return true;
1161
1162 /* Initiate or update synch mode if applicable */
1163 if ((usr == TUNNEL_PROTOCOL) && (mtyp == SYNCH_MSG)) {
1164 syncpt = iseqno + exp_pkts - 1;
1165 if (!tipc_link_is_up(l)) {
1166 tipc_link_fsm_evt(l, LINK_ESTABLISH_EVT);
1167 __tipc_node_link_up(n, bearer_id, xmitq);
1168 }
1169 if (n->state == SELF_UP_PEER_UP) {
1170 n->sync_point = syncpt;
1171 tipc_link_fsm_evt(l, LINK_SYNCH_BEGIN_EVT);
1172 tipc_node_fsm_evt(n, NODE_SYNCH_BEGIN_EVT);
1173 }
1174 if (less(syncpt, n->sync_point))
1175 n->sync_point = syncpt;
1176 }
1177
1178 /* Open tunnel link when parallel link reaches synch point */
1179 if ((n->state == NODE_SYNCHING) && tipc_link_is_synching(l)) {
1180 if (tipc_link_is_synching(l)) {
1181 tnl = l;
1182 } else {
1183 tnl = pl;
1184 pl = l;
1185 }
1186 dlv_nxt = pl->rcv_nxt - mod(skb_queue_len(pl->inputq));
1187 if (more(dlv_nxt, n->sync_point)) {
1188 tipc_link_fsm_evt(tnl, LINK_SYNCH_END_EVT);
1189 tipc_node_fsm_evt(n, NODE_SYNCH_END_EVT);
1190 return true;
1191 }
1192 if (l == pl)
1193 return true;
1194 if ((usr == TUNNEL_PROTOCOL) && (mtyp == SYNCH_MSG))
1195 return true;
1196 if (usr == LINK_PROTOCOL)
1197 return true;
1198 return false;
1199 }
1200 return true;
1201 }
1202
1203 /**
1204 * tipc_rcv - process TIPC packets/messages arriving from off-node
1205 * @net: the applicable net namespace
1206 * @skb: TIPC packet
1207 * @bearer: pointer to bearer message arrived on
1208 *
1209 * Invoked with no locks held. Bearer pointer must point to a valid bearer
1210 * structure (i.e. cannot be NULL), but bearer can be inactive.
1211 */
1212 void tipc_rcv(struct net *net, struct sk_buff *skb, struct tipc_bearer *b)
1213 {
1214 struct sk_buff_head xmitq;
1215 struct tipc_node *n;
1216 struct tipc_msg *hdr = buf_msg(skb);
1217 int usr = msg_user(hdr);
1218 int bearer_id = b->identity;
1219 struct tipc_link_entry *le;
1220 int rc = 0;
1221
1222 __skb_queue_head_init(&xmitq);
1223
1224 /* Ensure message is well-formed */
1225 if (unlikely(!tipc_msg_validate(skb)))
1226 goto discard;
1227
1228 /* Handle arrival of a non-unicast link packet */
1229 if (unlikely(msg_non_seq(hdr))) {
1230 if (usr == LINK_CONFIG)
1231 tipc_disc_rcv(net, skb, b);
1232 else
1233 tipc_bclink_rcv(net, skb);
1234 return;
1235 }
1236
1237 /* Locate neighboring node that sent packet */
1238 n = tipc_node_find(net, msg_prevnode(hdr));
1239 if (unlikely(!n))
1240 goto discard;
1241 le = &n->links[bearer_id];
1242
1243 tipc_node_lock(n);
1244
1245 /* Is reception permitted at the moment ? */
1246 if (!tipc_node_filter_pkt(n, hdr))
1247 goto unlock;
1248
1249 if (unlikely(msg_user(hdr) == LINK_PROTOCOL))
1250 tipc_bclink_sync_state(n, hdr);
1251
1252 /* Release acked broadcast packets */
1253 if (unlikely(n->bclink.acked != msg_bcast_ack(hdr)))
1254 tipc_bclink_acknowledge(n, msg_bcast_ack(hdr));
1255
1256 /* Check and if necessary update node state */
1257 if (likely(tipc_node_check_state(n, skb, bearer_id, &xmitq))) {
1258 rc = tipc_link_rcv(le->link, skb, &xmitq);
1259 skb = NULL;
1260 }
1261 unlock:
1262 tipc_node_unlock(n);
1263
1264 if (unlikely(rc & TIPC_LINK_UP_EVT))
1265 tipc_node_link_up(n, bearer_id, &xmitq);
1266
1267 if (unlikely(rc & TIPC_LINK_DOWN_EVT))
1268 tipc_node_link_down(n, bearer_id, false);
1269
1270 if (unlikely(!skb_queue_empty(&n->bclink.namedq)))
1271 tipc_named_rcv(net, &n->bclink.namedq);
1272
1273 if (!skb_queue_empty(&le->inputq))
1274 tipc_sk_rcv(net, &le->inputq);
1275
1276 if (!skb_queue_empty(&xmitq))
1277 tipc_bearer_xmit(net, bearer_id, &xmitq, &le->maddr);
1278
1279 tipc_node_put(n);
1280 discard:
1281 kfree_skb(skb);
1282 }
1283
1284 int tipc_nl_node_dump(struct sk_buff *skb, struct netlink_callback *cb)
1285 {
1286 int err;
1287 struct net *net = sock_net(skb->sk);
1288 struct tipc_net *tn = net_generic(net, tipc_net_id);
1289 int done = cb->args[0];
1290 int last_addr = cb->args[1];
1291 struct tipc_node *node;
1292 struct tipc_nl_msg msg;
1293
1294 if (done)
1295 return 0;
1296
1297 msg.skb = skb;
1298 msg.portid = NETLINK_CB(cb->skb).portid;
1299 msg.seq = cb->nlh->nlmsg_seq;
1300
1301 rcu_read_lock();
1302 if (last_addr) {
1303 node = tipc_node_find(net, last_addr);
1304 if (!node) {
1305 rcu_read_unlock();
1306 /* We never set seq or call nl_dump_check_consistent()
1307 * this means that setting prev_seq here will cause the
1308 * consistence check to fail in the netlink callback
1309 * handler. Resulting in the NLMSG_DONE message having
1310 * the NLM_F_DUMP_INTR flag set if the node state
1311 * changed while we released the lock.
1312 */
1313 cb->prev_seq = 1;
1314 return -EPIPE;
1315 }
1316 tipc_node_put(node);
1317 }
1318
1319 list_for_each_entry_rcu(node, &tn->node_list, list) {
1320 if (last_addr) {
1321 if (node->addr == last_addr)
1322 last_addr = 0;
1323 else
1324 continue;
1325 }
1326
1327 tipc_node_lock(node);
1328 err = __tipc_nl_add_node(&msg, node);
1329 if (err) {
1330 last_addr = node->addr;
1331 tipc_node_unlock(node);
1332 goto out;
1333 }
1334
1335 tipc_node_unlock(node);
1336 }
1337 done = 1;
1338 out:
1339 cb->args[0] = done;
1340 cb->args[1] = last_addr;
1341 rcu_read_unlock();
1342
1343 return skb->len;
1344 }
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