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v3.1
  1/*
  2 * net/tipc/node.c: TIPC node management routines
  3 *
  4 * Copyright (c) 2000-2006, Ericsson AB
  5 * Copyright (c) 2005-2006, 2010-2011, 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 "config.h"
 39#include "node.h"
 40#include "name_distr.h"
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 41
 42static void node_lost_contact(struct tipc_node *n_ptr);
 43static void node_established_contact(struct tipc_node *n_ptr);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 44
 45static DEFINE_SPINLOCK(node_create_lock);
 
 
 46
 47static struct hlist_head node_htable[NODE_HTABLE_SIZE];
 48LIST_HEAD(tipc_node_list);
 49static u32 tipc_num_nodes;
 50
 51static atomic_t tipc_num_links = ATOMIC_INIT(0);
 52u32 tipc_own_tag;
 53
 54/**
 55 * tipc_node_find - locate specified node object, if it exists
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 56 */
 
 
 
 
 57
 58struct tipc_node *tipc_node_find(u32 addr)
 59{
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 60	struct tipc_node *node;
 61	struct hlist_node *pos;
 62
 63	if (unlikely(!in_own_cluster(addr)))
 64		return NULL;
 65
 66	hlist_for_each_entry(node, pos, &node_htable[tipc_hashfn(addr)], hash) {
 67		if (node->addr == addr)
 68			return node;
 
 
 
 
 69	}
 70	return NULL;
 
 71}
 72
 73/**
 74 * tipc_node_create - create neighboring node
 75 *
 76 * Currently, this routine is called by neighbor discovery code, which holds
 77 * net_lock for reading only.  We must take node_create_lock to ensure a node
 78 * isn't created twice if two different bearers discover the node at the same
 79 * time.  (It would be preferable to switch to holding net_lock in write mode,
 80 * but this is a non-trivial change.)
 81 */
 82
 83struct tipc_node *tipc_node_create(u32 addr)
 84{
 85	struct tipc_node *n_ptr, *temp_node;
 
 86
 87	spin_lock_bh(&node_create_lock);
 
 
 
 88
 89	n_ptr = tipc_node_find(addr);
 90	if (n_ptr) {
 91		spin_unlock_bh(&node_create_lock);
 92		return n_ptr;
 93	}
 
 
 94
 95	n_ptr = kzalloc(sizeof(*n_ptr), GFP_ATOMIC);
 96	if (!n_ptr) {
 97		spin_unlock_bh(&node_create_lock);
 98		warn("Node creation failed, no memory\n");
 99		return NULL;
100	}
101
102	n_ptr->addr = addr;
103	spin_lock_init(&n_ptr->lock);
104	INIT_HLIST_NODE(&n_ptr->hash);
105	INIT_LIST_HEAD(&n_ptr->list);
106	INIT_LIST_HEAD(&n_ptr->nsub);
 
 
 
 
 
 
107
108	hlist_add_head(&n_ptr->hash, &node_htable[tipc_hashfn(addr)]);
 
109
110	list_for_each_entry(temp_node, &tipc_node_list, list) {
111		if (n_ptr->addr < temp_node->addr)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
112			break;
113	}
114	list_add_tail(&n_ptr->list, &temp_node->list);
 
 
 
 
115
116	tipc_num_nodes++;
 
 
 
 
 
 
 
 
117
118	spin_unlock_bh(&node_create_lock);
119	return n_ptr;
120}
121
122void tipc_node_delete(struct tipc_node *n_ptr)
123{
124	list_del(&n_ptr->list);
125	hlist_del(&n_ptr->hash);
126	kfree(n_ptr);
127
128	tipc_num_nodes--;
 
129}
130
 
 
 
 
131
132/**
133 * tipc_node_link_up - handle addition of link
134 *
135 * Link becomes active (alone or shared) or standby, depending on its priority.
136 */
137
138void tipc_node_link_up(struct tipc_node *n_ptr, struct link *l_ptr)
139{
140	struct link **active = &n_ptr->active_links[0];
141
142	n_ptr->working_links++;
143
144	info("Established link <%s> on network plane %c\n",
145	     l_ptr->name, l_ptr->b_ptr->net_plane);
146
147	if (!active[0]) {
148		active[0] = active[1] = l_ptr;
149		node_established_contact(n_ptr);
150		return;
151	}
152	if (l_ptr->priority < active[0]->priority) {
153		info("New link <%s> becomes standby\n", l_ptr->name);
 
 
 
 
 
 
 
 
 
154		return;
155	}
156	tipc_link_send_duplicate(active[0], l_ptr);
157	if (l_ptr->priority == active[0]->priority) {
158		active[0] = l_ptr;
159		return;
160	}
161	info("Old link <%s> becomes standby\n", active[0]->name);
162	if (active[1] != active[0])
163		info("Old link <%s> becomes standby\n", active[1]->name);
164	active[0] = active[1] = l_ptr;
165}
166
167/**
168 * node_select_active_links - select active link
169 */
 
 
170
171static void node_select_active_links(struct tipc_node *n_ptr)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
172{
173	struct link **active = &n_ptr->active_links[0];
174	u32 i;
175	u32 highest_prio = 0;
176
177	active[0] = active[1] = NULL;
 
178
179	for (i = 0; i < MAX_BEARERS; i++) {
180		struct link *l_ptr = n_ptr->links[i];
 
181
182		if (!l_ptr || !tipc_link_is_up(l_ptr) ||
183		    (l_ptr->priority < highest_prio))
 
184			continue;
 
 
 
 
 
 
185
186		if (l_ptr->priority > highest_prio) {
187			highest_prio = l_ptr->priority;
188			active[0] = active[1] = l_ptr;
189		} else {
190			active[1] = l_ptr;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
191		}
 
 
 
 
 
192	}
 
193}
194
195/**
196 * tipc_node_link_down - handle loss of link
 
 
197 */
198
199void tipc_node_link_down(struct tipc_node *n_ptr, struct link *l_ptr)
200{
201	struct link **active;
 
 
 
202
203	n_ptr->working_links--;
 
204
205	if (!tipc_link_is_active(l_ptr)) {
206		info("Lost standby link <%s> on network plane %c\n",
207		     l_ptr->name, l_ptr->b_ptr->net_plane);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
208		return;
209	}
210	info("Lost link <%s> on network plane %c\n",
211		l_ptr->name, l_ptr->b_ptr->net_plane);
212
213	active = &n_ptr->active_links[0];
214	if (active[0] == l_ptr)
215		active[0] = active[1];
216	if (active[1] == l_ptr)
217		active[1] = active[0];
218	if (active[0] == l_ptr)
219		node_select_active_links(n_ptr);
220	if (tipc_node_is_up(n_ptr))
221		tipc_link_changeover(l_ptr);
222	else
223		node_lost_contact(n_ptr);
 
 
 
 
 
224}
225
226int tipc_node_active_links(struct tipc_node *n_ptr)
 
 
 
 
 
 
227{
228	return n_ptr->active_links[0] != NULL;
 
 
229}
230
231int tipc_node_redundant_links(struct tipc_node *n_ptr)
 
 
 
 
 
232{
233	return n_ptr->working_links > 1;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
234}
235
236int tipc_node_is_up(struct tipc_node *n_ptr)
237{
238	return tipc_node_active_links(n_ptr);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
239}
240
241void tipc_node_attach_link(struct tipc_node *n_ptr, struct link *l_ptr)
242{
243	n_ptr->links[l_ptr->b_ptr->identity] = l_ptr;
244	atomic_inc(&tipc_num_links);
245	n_ptr->link_cnt++;
246}
247
248void tipc_node_detach_link(struct tipc_node *n_ptr, struct link *l_ptr)
 
 
 
 
249{
250	n_ptr->links[l_ptr->b_ptr->identity] = NULL;
251	atomic_dec(&tipc_num_links);
252	n_ptr->link_cnt--;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
253}
254
255/*
256 * Routing table management - five cases to handle:
257 *
258 * 1: A link towards a zone/cluster external node comes up.
259 *    => Send a multicast message updating routing tables of all
260 *    system nodes within own cluster that the new destination
261 *    can be reached via this node.
262 *    (node.establishedContact()=>cluster.multicastNewRoute())
263 *
264 * 2: A link towards a slave node comes up.
265 *    => Send a multicast message updating routing tables of all
266 *    system nodes within own cluster that the new destination
267 *    can be reached via this node.
268 *    (node.establishedContact()=>cluster.multicastNewRoute())
269 *    => Send a  message to the slave node about existence
270 *    of all system nodes within cluster:
271 *    (node.establishedContact()=>cluster.sendLocalRoutes())
272 *
273 * 3: A new cluster local system node becomes available.
274 *    => Send message(s) to this particular node containing
275 *    information about all cluster external and slave
276 *     nodes which can be reached via this node.
277 *    (node.establishedContact()==>network.sendExternalRoutes())
278 *    (node.establishedContact()==>network.sendSlaveRoutes())
279 *    => Send messages to all directly connected slave nodes
280 *    containing information about the existence of the new node
281 *    (node.establishedContact()=>cluster.multicastNewRoute())
282 *
283 * 4: The link towards a zone/cluster external node or slave
284 *    node goes down.
285 *    => Send a multcast message updating routing tables of all
286 *    nodes within cluster that the new destination can not any
287 *    longer be reached via this node.
288 *    (node.lostAllLinks()=>cluster.bcastLostRoute())
289 *
290 * 5: A cluster local system node becomes unavailable.
291 *    => Remove all references to this node from the local
292 *    routing tables. Note: This is a completely node
293 *    local operation.
294 *    (node.lostAllLinks()=>network.removeAsRouter())
295 *    => Send messages to all directly connected slave nodes
296 *    containing information about loss of the node
297 *    (node.establishedContact()=>cluster.multicastLostRoute())
298 *
299 */
300
301static void node_established_contact(struct tipc_node *n_ptr)
302{
303	tipc_k_signal((Handler)tipc_named_node_up, n_ptr->addr);
 
304
305	/* Syncronize broadcast acks */
306	n_ptr->bclink.acked = tipc_bclink_get_last_sent();
307
308	if (n_ptr->bclink.supported) {
309		tipc_nmap_add(&tipc_bcast_nmap, n_ptr->addr);
310		if (n_ptr->addr < tipc_own_addr)
311			tipc_own_tag++;
312	}
313}
314
315static void node_cleanup_finished(unsigned long node_addr)
 
 
 
316{
317	struct tipc_node *n_ptr;
318
319	read_lock_bh(&tipc_net_lock);
320	n_ptr = tipc_node_find(node_addr);
321	if (n_ptr) {
322		tipc_node_lock(n_ptr);
323		n_ptr->cleanup_required = 0;
324		tipc_node_unlock(n_ptr);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
325	}
326	read_unlock_bh(&tipc_net_lock);
 
 
 
 
327}
328
329static void node_lost_contact(struct tipc_node *n_ptr)
 
330{
331	char addr_string[16];
332	u32 i;
 
 
 
 
333
334	/* Clean up broadcast reception remains */
335	n_ptr->bclink.gap_after = n_ptr->bclink.gap_to = 0;
336	while (n_ptr->bclink.deferred_head) {
337		struct sk_buff *buf = n_ptr->bclink.deferred_head;
338		n_ptr->bclink.deferred_head = buf->next;
339		buf_discard(buf);
340	}
341	if (n_ptr->bclink.defragm) {
342		buf_discard(n_ptr->bclink.defragm);
343		n_ptr->bclink.defragm = NULL;
344	}
345
346	if (n_ptr->bclink.supported) {
347		tipc_bclink_acknowledge(n_ptr,
348					mod(n_ptr->bclink.acked + 10000));
349		tipc_nmap_remove(&tipc_bcast_nmap, n_ptr->addr);
350		if (n_ptr->addr < tipc_own_addr)
351			tipc_own_tag--;
352	}
353
354	info("Lost contact with %s\n",
355	     tipc_addr_string_fill(addr_string, n_ptr->addr));
356
357	/* Abort link changeover */
358	for (i = 0; i < MAX_BEARERS; i++) {
359		struct link *l_ptr = n_ptr->links[i];
360		if (!l_ptr)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
361			continue;
362		l_ptr->reset_checkpoint = l_ptr->next_in_no;
363		l_ptr->exp_msg_count = 0;
364		tipc_link_reset_fragments(l_ptr);
 
 
365	}
 
 
 
 
366
367	/* Notify subscribers */
368	tipc_nodesub_notify(n_ptr);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
369
370	/* Prevent re-contact with node until all cleanup is done */
371
372	n_ptr->cleanup_required = 1;
373	tipc_k_signal((Handler)node_cleanup_finished, n_ptr->addr);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
374}
375
376struct sk_buff *tipc_node_get_nodes(const void *req_tlv_area, int req_tlv_space)
 
 
 
 
 
 
 
377{
378	u32 domain;
379	struct sk_buff *buf;
380	struct tipc_node *n_ptr;
381	struct tipc_node_info node_info;
382	u32 payload_size;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
383
384	if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_NET_ADDR))
385		return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
386
387	domain = ntohl(*(__be32 *)TLV_DATA(req_tlv_area));
388	if (!tipc_addr_domain_valid(domain))
389		return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
390						   " (network address)");
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
391
392	read_lock_bh(&tipc_net_lock);
393	if (!tipc_num_nodes) {
394		read_unlock_bh(&tipc_net_lock);
395		return tipc_cfg_reply_none();
 
 
 
 
 
 
396	}
397
398	/* For now, get space for all other nodes */
 
 
 
 
 
 
 
 
 
 
399
400	payload_size = TLV_SPACE(sizeof(node_info)) * tipc_num_nodes;
401	if (payload_size > 32768u) {
402		read_unlock_bh(&tipc_net_lock);
403		return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
404						   " (too many nodes)");
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
405	}
406	buf = tipc_cfg_reply_alloc(payload_size);
407	if (!buf) {
408		read_unlock_bh(&tipc_net_lock);
409		return NULL;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
410	}
 
 
 
 
 
411
412	/* Add TLVs for all nodes in scope */
 
413
414	list_for_each_entry(n_ptr, &tipc_node_list, list) {
415		if (!tipc_in_scope(domain, n_ptr->addr))
416			continue;
417		node_info.addr = htonl(n_ptr->addr);
418		node_info.up = htonl(tipc_node_is_up(n_ptr));
419		tipc_cfg_append_tlv(buf, TIPC_TLV_NODE_INFO,
420				    &node_info, sizeof(node_info));
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
421	}
 
422
423	read_unlock_bh(&tipc_net_lock);
424	return buf;
425}
426
427struct sk_buff *tipc_node_get_links(const void *req_tlv_area, int req_tlv_space)
428{
429	u32 domain;
430	struct sk_buff *buf;
431	struct tipc_node *n_ptr;
432	struct tipc_link_info link_info;
433	u32 payload_size;
 
 
 
 
 
 
434
435	if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_NET_ADDR))
436		return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
437
438	domain = ntohl(*(__be32 *)TLV_DATA(req_tlv_area));
439	if (!tipc_addr_domain_valid(domain))
440		return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
441						   " (network address)");
 
442
443	if (tipc_mode != TIPC_NET_MODE)
444		return tipc_cfg_reply_none();
445
446	read_lock_bh(&tipc_net_lock);
447
448	/* Get space for all unicast links + multicast link */
 
449
450	payload_size = TLV_SPACE(sizeof(link_info)) *
451		(atomic_read(&tipc_num_links) + 1);
452	if (payload_size > 32768u) {
453		read_unlock_bh(&tipc_net_lock);
454		return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
455						   " (too many links)");
 
 
 
 
456	}
457	buf = tipc_cfg_reply_alloc(payload_size);
458	if (!buf) {
459		read_unlock_bh(&tipc_net_lock);
460		return NULL;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
461	}
462
463	/* Add TLV for broadcast link */
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
464
465	link_info.dest = htonl(tipc_cluster_mask(tipc_own_addr));
466	link_info.up = htonl(1);
467	strlcpy(link_info.str, tipc_bclink_name, TIPC_MAX_LINK_NAME);
468	tipc_cfg_append_tlv(buf, TIPC_TLV_LINK_INFO, &link_info, sizeof(link_info));
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
469
470	/* Add TLVs for any other links in scope */
 
 
 
 
 
471
472	list_for_each_entry(n_ptr, &tipc_node_list, list) {
473		u32 i;
474
475		if (!tipc_in_scope(domain, n_ptr->addr))
476			continue;
477		tipc_node_lock(n_ptr);
478		for (i = 0; i < MAX_BEARERS; i++) {
479			if (!n_ptr->links[i])
480				continue;
481			link_info.dest = htonl(n_ptr->addr);
482			link_info.up = htonl(tipc_link_is_up(n_ptr->links[i]));
483			strcpy(link_info.str, n_ptr->links[i]->name);
484			tipc_cfg_append_tlv(buf, TIPC_TLV_LINK_INFO,
485					    &link_info, sizeof(link_info));
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
486		}
487		tipc_node_unlock(n_ptr);
488	}
 
 
 
 
 
 
 
489
490	read_unlock_bh(&tipc_net_lock);
491	return buf;
492}
v4.6
   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#include "netlink.h"
  45
  46#define INVALID_NODE_SIG	0x10000
  47
  48/* Flags used to take different actions according to flag type
  49 * TIPC_NOTIFY_NODE_DOWN: notify node is down
  50 * TIPC_NOTIFY_NODE_UP: notify node is up
  51 * TIPC_DISTRIBUTE_NAME: publish or withdraw link state name type
  52 */
  53enum {
  54	TIPC_NOTIFY_NODE_DOWN		= (1 << 3),
  55	TIPC_NOTIFY_NODE_UP		= (1 << 4),
  56	TIPC_NOTIFY_LINK_UP		= (1 << 6),
  57	TIPC_NOTIFY_LINK_DOWN		= (1 << 7)
  58};
  59
  60struct tipc_link_entry {
  61	struct tipc_link *link;
  62	spinlock_t lock; /* per link */
  63	u32 mtu;
  64	struct sk_buff_head inputq;
  65	struct tipc_media_addr maddr;
  66};
  67
  68struct tipc_bclink_entry {
  69	struct tipc_link *link;
  70	struct sk_buff_head inputq1;
  71	struct sk_buff_head arrvq;
  72	struct sk_buff_head inputq2;
  73	struct sk_buff_head namedq;
  74};
  75
  76/**
  77 * struct tipc_node - TIPC node structure
  78 * @addr: network address of node
  79 * @ref: reference counter to node object
  80 * @lock: rwlock governing access to structure
  81 * @net: the applicable net namespace
  82 * @hash: links to adjacent nodes in unsorted hash chain
  83 * @inputq: pointer to input queue containing messages for msg event
  84 * @namedq: pointer to name table input queue with name table messages
  85 * @active_links: bearer ids of active links, used as index into links[] array
  86 * @links: array containing references to all links to node
  87 * @action_flags: bit mask of different types of node actions
  88 * @state: connectivity state vs peer node
  89 * @sync_point: sequence number where synch/failover is finished
  90 * @list: links to adjacent nodes in sorted list of cluster's nodes
  91 * @working_links: number of working links to node (both active and standby)
  92 * @link_cnt: number of links to node
  93 * @capabilities: bitmap, indicating peer node's functional capabilities
  94 * @signature: node instance identifier
  95 * @link_id: local and remote bearer ids of changing link, if any
  96 * @publ_list: list of publications
  97 * @rcu: rcu struct for tipc_node
  98 */
  99struct tipc_node {
 100	u32 addr;
 101	struct kref kref;
 102	rwlock_t lock;
 103	struct net *net;
 104	struct hlist_node hash;
 105	int active_links[2];
 106	struct tipc_link_entry links[MAX_BEARERS];
 107	struct tipc_bclink_entry bc_entry;
 108	int action_flags;
 109	struct list_head list;
 110	int state;
 111	u16 sync_point;
 112	int link_cnt;
 113	u16 working_links;
 114	u16 capabilities;
 115	u32 signature;
 116	u32 link_id;
 117	struct list_head publ_list;
 118	struct list_head conn_sks;
 119	unsigned long keepalive_intv;
 120	struct timer_list timer;
 121	struct rcu_head rcu;
 122};
 123
 124/* Node FSM states and events:
 125 */
 126enum {
 127	SELF_DOWN_PEER_DOWN    = 0xdd,
 128	SELF_UP_PEER_UP        = 0xaa,
 129	SELF_DOWN_PEER_LEAVING = 0xd1,
 130	SELF_UP_PEER_COMING    = 0xac,
 131	SELF_COMING_PEER_UP    = 0xca,
 132	SELF_LEAVING_PEER_DOWN = 0x1d,
 133	NODE_FAILINGOVER       = 0xf0,
 134	NODE_SYNCHING          = 0xcc
 135};
 136
 137enum {
 138	SELF_ESTABL_CONTACT_EVT = 0xece,
 139	SELF_LOST_CONTACT_EVT   = 0x1ce,
 140	PEER_ESTABL_CONTACT_EVT = 0x9ece,
 141	PEER_LOST_CONTACT_EVT   = 0x91ce,
 142	NODE_FAILOVER_BEGIN_EVT = 0xfbe,
 143	NODE_FAILOVER_END_EVT   = 0xfee,
 144	NODE_SYNCH_BEGIN_EVT    = 0xcbe,
 145	NODE_SYNCH_END_EVT      = 0xcee
 146};
 147
 148static void __tipc_node_link_down(struct tipc_node *n, int *bearer_id,
 149				  struct sk_buff_head *xmitq,
 150				  struct tipc_media_addr **maddr);
 151static void tipc_node_link_down(struct tipc_node *n, int bearer_id,
 152				bool delete);
 153static void node_lost_contact(struct tipc_node *n, struct sk_buff_head *inputq);
 154static void tipc_node_delete(struct tipc_node *node);
 155static void tipc_node_timeout(unsigned long data);
 156static void tipc_node_fsm_evt(struct tipc_node *n, int evt);
 157static struct tipc_node *tipc_node_find(struct net *net, u32 addr);
 158static void tipc_node_put(struct tipc_node *node);
 159static bool tipc_node_is_up(struct tipc_node *n);
 160
 161struct tipc_sock_conn {
 162	u32 port;
 163	u32 peer_port;
 164	u32 peer_node;
 165	struct list_head list;
 166};
 167
 168static struct tipc_link *node_active_link(struct tipc_node *n, int sel)
 169{
 170	int bearer_id = n->active_links[sel & 1];
 171
 172	if (unlikely(bearer_id == INVALID_BEARER_ID))
 173		return NULL;
 
 174
 175	return n->links[bearer_id].link;
 176}
 177
 178int tipc_node_get_mtu(struct net *net, u32 addr, u32 sel)
 179{
 180	struct tipc_node *n;
 181	int bearer_id;
 182	unsigned int mtu = MAX_MSG_SIZE;
 183
 184	n = tipc_node_find(net, addr);
 185	if (unlikely(!n))
 186		return mtu;
 187
 188	bearer_id = n->active_links[sel & 1];
 189	if (likely(bearer_id != INVALID_BEARER_ID))
 190		mtu = n->links[bearer_id].mtu;
 191	tipc_node_put(n);
 192	return mtu;
 193}
 194/*
 195 * A trivial power-of-two bitmask technique is used for speed, since this
 196 * operation is done for every incoming TIPC packet. The number of hash table
 197 * entries has been chosen so that no hash chain exceeds 8 nodes and will
 198 * usually be much smaller (typically only a single node).
 199 */
 200static unsigned int tipc_hashfn(u32 addr)
 201{
 202	return addr & (NODE_HTABLE_SIZE - 1);
 203}
 204
 205static void tipc_node_kref_release(struct kref *kref)
 206{
 207	struct tipc_node *n = container_of(kref, struct tipc_node, kref);
 208
 209	kfree(n->bc_entry.link);
 210	kfree_rcu(n, rcu);
 211}
 212
 213static void tipc_node_put(struct tipc_node *node)
 214{
 215	kref_put(&node->kref, tipc_node_kref_release);
 216}
 217
 218static void tipc_node_get(struct tipc_node *node)
 219{
 220	kref_get(&node->kref);
 221}
 222
 223/*
 224 * tipc_node_find - locate specified node object, if it exists
 225 */
 226static struct tipc_node *tipc_node_find(struct net *net, u32 addr)
 227{
 228	struct tipc_net *tn = tipc_net(net);
 229	struct tipc_node *node;
 230	unsigned int thash = tipc_hashfn(addr);
 231
 232	if (unlikely(!in_own_cluster_exact(net, addr)))
 233		return NULL;
 234
 235	rcu_read_lock();
 236	hlist_for_each_entry_rcu(node, &tn->node_htable[thash], hash) {
 237		if (node->addr != addr)
 238			continue;
 239		if (!kref_get_unless_zero(&node->kref))
 240			node = NULL;
 241		break;
 242	}
 243	rcu_read_unlock();
 244	return node;
 245}
 246
 247static void tipc_node_read_lock(struct tipc_node *n)
 248{
 249	read_lock_bh(&n->lock);
 250}
 
 
 
 
 
 251
 252static void tipc_node_read_unlock(struct tipc_node *n)
 253{
 254	read_unlock_bh(&n->lock);
 255}
 256
 257static void tipc_node_write_lock(struct tipc_node *n)
 258{
 259	write_lock_bh(&n->lock);
 260}
 261
 262static void tipc_node_write_unlock(struct tipc_node *n)
 263{
 264	struct net *net = n->net;
 265	u32 addr = 0;
 266	u32 flags = n->action_flags;
 267	u32 link_id = 0;
 268	struct list_head *publ_list;
 269
 270	if (likely(!flags)) {
 271		write_unlock_bh(&n->lock);
 272		return;
 
 
 273	}
 274
 275	addr = n->addr;
 276	link_id = n->link_id;
 277	publ_list = &n->publ_list;
 278
 279	n->action_flags &= ~(TIPC_NOTIFY_NODE_DOWN | TIPC_NOTIFY_NODE_UP |
 280			     TIPC_NOTIFY_LINK_DOWN | TIPC_NOTIFY_LINK_UP);
 281
 282	write_unlock_bh(&n->lock);
 283
 284	if (flags & TIPC_NOTIFY_NODE_DOWN)
 285		tipc_publ_notify(net, publ_list, addr);
 286
 287	if (flags & TIPC_NOTIFY_NODE_UP)
 288		tipc_named_node_up(net, addr);
 289
 290	if (flags & TIPC_NOTIFY_LINK_UP)
 291		tipc_nametbl_publish(net, TIPC_LINK_STATE, addr, addr,
 292				     TIPC_NODE_SCOPE, link_id, addr);
 293
 294	if (flags & TIPC_NOTIFY_LINK_DOWN)
 295		tipc_nametbl_withdraw(net, TIPC_LINK_STATE, addr,
 296				      link_id, addr);
 297}
 298
 299struct tipc_node *tipc_node_create(struct net *net, u32 addr, u16 capabilities)
 300{
 301	struct tipc_net *tn = net_generic(net, tipc_net_id);
 302	struct tipc_node *n, *temp_node;
 303	int i;
 304
 305	spin_lock_bh(&tn->node_list_lock);
 306	n = tipc_node_find(net, addr);
 307	if (n)
 308		goto exit;
 309	n = kzalloc(sizeof(*n), GFP_ATOMIC);
 310	if (!n) {
 311		pr_warn("Node creation failed, no memory\n");
 312		goto exit;
 313	}
 314	n->addr = addr;
 315	n->net = net;
 316	n->capabilities = capabilities;
 317	kref_init(&n->kref);
 318	rwlock_init(&n->lock);
 319	INIT_HLIST_NODE(&n->hash);
 320	INIT_LIST_HEAD(&n->list);
 321	INIT_LIST_HEAD(&n->publ_list);
 322	INIT_LIST_HEAD(&n->conn_sks);
 323	skb_queue_head_init(&n->bc_entry.namedq);
 324	skb_queue_head_init(&n->bc_entry.inputq1);
 325	__skb_queue_head_init(&n->bc_entry.arrvq);
 326	skb_queue_head_init(&n->bc_entry.inputq2);
 327	for (i = 0; i < MAX_BEARERS; i++)
 328		spin_lock_init(&n->links[i].lock);
 329	n->state = SELF_DOWN_PEER_LEAVING;
 330	n->signature = INVALID_NODE_SIG;
 331	n->active_links[0] = INVALID_BEARER_ID;
 332	n->active_links[1] = INVALID_BEARER_ID;
 333	if (!tipc_link_bc_create(net, tipc_own_addr(net), n->addr,
 334				 U16_MAX,
 335				 tipc_link_window(tipc_bc_sndlink(net)),
 336				 n->capabilities,
 337				 &n->bc_entry.inputq1,
 338				 &n->bc_entry.namedq,
 339				 tipc_bc_sndlink(net),
 340				 &n->bc_entry.link)) {
 341		pr_warn("Broadcast rcv link creation failed, no memory\n");
 342		kfree(n);
 343		n = NULL;
 344		goto exit;
 345	}
 346	tipc_node_get(n);
 347	setup_timer(&n->timer, tipc_node_timeout, (unsigned long)n);
 348	n->keepalive_intv = U32_MAX;
 349	hlist_add_head_rcu(&n->hash, &tn->node_htable[tipc_hashfn(addr)]);
 350	list_for_each_entry_rcu(temp_node, &tn->node_list, list) {
 351		if (n->addr < temp_node->addr)
 352			break;
 353	}
 354	list_add_tail_rcu(&n->list, &temp_node->list);
 355exit:
 356	spin_unlock_bh(&tn->node_list_lock);
 357	return n;
 358}
 359
 360static void tipc_node_calculate_timer(struct tipc_node *n, struct tipc_link *l)
 361{
 362	unsigned long tol = tipc_link_tolerance(l);
 363	unsigned long intv = ((tol / 4) > 500) ? 500 : tol / 4;
 364	unsigned long keepalive_intv = msecs_to_jiffies(intv);
 365
 366	/* Link with lowest tolerance determines timer interval */
 367	if (keepalive_intv < n->keepalive_intv)
 368		n->keepalive_intv = keepalive_intv;
 369
 370	/* Ensure link's abort limit corresponds to current interval */
 371	tipc_link_set_abort_limit(l, tol / jiffies_to_msecs(n->keepalive_intv));
 372}
 373
 374static void tipc_node_delete(struct tipc_node *node)
 375{
 376	list_del_rcu(&node->list);
 377	hlist_del_rcu(&node->hash);
 378	tipc_node_put(node);
 379
 380	del_timer_sync(&node->timer);
 381	tipc_node_put(node);
 382}
 383
 384void tipc_node_stop(struct net *net)
 385{
 386	struct tipc_net *tn = tipc_net(net);
 387	struct tipc_node *node, *t_node;
 388
 389	spin_lock_bh(&tn->node_list_lock);
 390	list_for_each_entry_safe(node, t_node, &tn->node_list, list)
 391		tipc_node_delete(node);
 392	spin_unlock_bh(&tn->node_list_lock);
 393}
 394
 395void tipc_node_subscribe(struct net *net, struct list_head *subscr, u32 addr)
 396{
 397	struct tipc_node *n;
 398
 399	if (in_own_node(net, addr))
 400		return;
 
 
 401
 402	n = tipc_node_find(net, addr);
 403	if (!n) {
 404		pr_warn("Node subscribe rejected, unknown node 0x%x\n", addr);
 405		return;
 406	}
 407	tipc_node_write_lock(n);
 408	list_add_tail(subscr, &n->publ_list);
 409	tipc_node_write_unlock(n);
 410	tipc_node_put(n);
 411}
 412
 413void tipc_node_unsubscribe(struct net *net, struct list_head *subscr, u32 addr)
 414{
 415	struct tipc_node *n;
 416
 417	if (in_own_node(net, addr))
 418		return;
 419
 420	n = tipc_node_find(net, addr);
 421	if (!n) {
 422		pr_warn("Node unsubscribe rejected, unknown node 0x%x\n", addr);
 423		return;
 424	}
 425	tipc_node_write_lock(n);
 426	list_del_init(subscr);
 427	tipc_node_write_unlock(n);
 428	tipc_node_put(n);
 429}
 430
 431int tipc_node_add_conn(struct net *net, u32 dnode, u32 port, u32 peer_port)
 432{
 433	struct tipc_node *node;
 434	struct tipc_sock_conn *conn;
 435	int err = 0;
 436
 437	if (in_own_node(net, dnode))
 438		return 0;
 439
 440	node = tipc_node_find(net, dnode);
 441	if (!node) {
 442		pr_warn("Connecting sock to node 0x%x failed\n", dnode);
 443		return -EHOSTUNREACH;
 444	}
 445	conn = kmalloc(sizeof(*conn), GFP_ATOMIC);
 446	if (!conn) {
 447		err = -EHOSTUNREACH;
 448		goto exit;
 449	}
 450	conn->peer_node = dnode;
 451	conn->port = port;
 452	conn->peer_port = peer_port;
 453
 454	tipc_node_write_lock(node);
 455	list_add_tail(&conn->list, &node->conn_sks);
 456	tipc_node_write_unlock(node);
 457exit:
 458	tipc_node_put(node);
 459	return err;
 460}
 461
 462void tipc_node_remove_conn(struct net *net, u32 dnode, u32 port)
 463{
 464	struct tipc_node *node;
 465	struct tipc_sock_conn *conn, *safe;
 
 466
 467	if (in_own_node(net, dnode))
 468		return;
 469
 470	node = tipc_node_find(net, dnode);
 471	if (!node)
 472		return;
 473
 474	tipc_node_write_lock(node);
 475	list_for_each_entry_safe(conn, safe, &node->conn_sks, list) {
 476		if (port != conn->port)
 477			continue;
 478		list_del(&conn->list);
 479		kfree(conn);
 480	}
 481	tipc_node_write_unlock(node);
 482	tipc_node_put(node);
 483}
 484
 485/* tipc_node_timeout - handle expiration of node timer
 486 */
 487static void tipc_node_timeout(unsigned long data)
 488{
 489	struct tipc_node *n = (struct tipc_node *)data;
 490	struct tipc_link_entry *le;
 491	struct sk_buff_head xmitq;
 492	int bearer_id;
 493	int rc = 0;
 494
 495	__skb_queue_head_init(&xmitq);
 496
 497	for (bearer_id = 0; bearer_id < MAX_BEARERS; bearer_id++) {
 498		tipc_node_read_lock(n);
 499		le = &n->links[bearer_id];
 500		spin_lock_bh(&le->lock);
 501		if (le->link) {
 502			/* Link tolerance may change asynchronously: */
 503			tipc_node_calculate_timer(n, le->link);
 504			rc = tipc_link_timeout(le->link, &xmitq);
 505		}
 506		spin_unlock_bh(&le->lock);
 507		tipc_node_read_unlock(n);
 508		tipc_bearer_xmit(n->net, bearer_id, &xmitq, &le->maddr);
 509		if (rc & TIPC_LINK_DOWN_EVT)
 510			tipc_node_link_down(n, bearer_id, false);
 511	}
 512	mod_timer(&n->timer, jiffies + n->keepalive_intv);
 513}
 514
 515/**
 516 * __tipc_node_link_up - handle addition of link
 517 * Node lock must be held by caller
 518 * Link becomes active (alone or shared) or standby, depending on its priority.
 519 */
 520static void __tipc_node_link_up(struct tipc_node *n, int bearer_id,
 521				struct sk_buff_head *xmitq)
 522{
 523	int *slot0 = &n->active_links[0];
 524	int *slot1 = &n->active_links[1];
 525	struct tipc_link *ol = node_active_link(n, 0);
 526	struct tipc_link *nl = n->links[bearer_id].link;
 527
 528	if (!nl)
 529		return;
 530
 531	tipc_link_fsm_evt(nl, LINK_ESTABLISH_EVT);
 532	if (!tipc_link_is_up(nl))
 533		return;
 534
 535	n->working_links++;
 536	n->action_flags |= TIPC_NOTIFY_LINK_UP;
 537	n->link_id = tipc_link_id(nl);
 538
 539	/* Leave room for tunnel header when returning 'mtu' to users: */
 540	n->links[bearer_id].mtu = tipc_link_mtu(nl) - INT_H_SIZE;
 541
 542	tipc_bearer_add_dest(n->net, bearer_id, n->addr);
 543	tipc_bcast_inc_bearer_dst_cnt(n->net, bearer_id);
 544
 545	pr_debug("Established link <%s> on network plane %c\n",
 546		 tipc_link_name(nl), tipc_link_plane(nl));
 547
 548	/* First link? => give it both slots */
 549	if (!ol) {
 550		*slot0 = bearer_id;
 551		*slot1 = bearer_id;
 552		tipc_node_fsm_evt(n, SELF_ESTABL_CONTACT_EVT);
 553		n->action_flags |= TIPC_NOTIFY_NODE_UP;
 554		tipc_bcast_add_peer(n->net, nl, xmitq);
 555		return;
 556	}
 
 
 557
 558	/* Second link => redistribute slots */
 559	if (tipc_link_prio(nl) > tipc_link_prio(ol)) {
 560		pr_debug("Old link <%s> becomes standby\n", tipc_link_name(ol));
 561		*slot0 = bearer_id;
 562		*slot1 = bearer_id;
 563		tipc_link_set_active(nl, true);
 564		tipc_link_set_active(ol, false);
 565	} else if (tipc_link_prio(nl) == tipc_link_prio(ol)) {
 566		tipc_link_set_active(nl, true);
 567		*slot1 = bearer_id;
 568	} else {
 569		pr_debug("New link <%s> is standby\n", tipc_link_name(nl));
 570	}
 571
 572	/* Prepare synchronization with first link */
 573	tipc_link_tnl_prepare(ol, nl, SYNCH_MSG, xmitq);
 574}
 575
 576/**
 577 * tipc_node_link_up - handle addition of link
 578 *
 579 * Link becomes active (alone or shared) or standby, depending on its priority.
 580 */
 581static void tipc_node_link_up(struct tipc_node *n, int bearer_id,
 582			      struct sk_buff_head *xmitq)
 583{
 584	tipc_node_write_lock(n);
 585	__tipc_node_link_up(n, bearer_id, xmitq);
 586	tipc_node_write_unlock(n);
 587}
 588
 589/**
 590 * __tipc_node_link_down - handle loss of link
 591 */
 592static void __tipc_node_link_down(struct tipc_node *n, int *bearer_id,
 593				  struct sk_buff_head *xmitq,
 594				  struct tipc_media_addr **maddr)
 595{
 596	struct tipc_link_entry *le = &n->links[*bearer_id];
 597	int *slot0 = &n->active_links[0];
 598	int *slot1 = &n->active_links[1];
 599	int i, highest = 0, prio;
 600	struct tipc_link *l, *_l, *tnl;
 601
 602	l = n->links[*bearer_id].link;
 603	if (!l || tipc_link_is_reset(l))
 604		return;
 605
 606	n->working_links--;
 607	n->action_flags |= TIPC_NOTIFY_LINK_DOWN;
 608	n->link_id = tipc_link_id(l);
 609
 610	tipc_bearer_remove_dest(n->net, *bearer_id, n->addr);
 611
 612	pr_debug("Lost link <%s> on network plane %c\n",
 613		 tipc_link_name(l), tipc_link_plane(l));
 614
 615	/* Select new active link if any available */
 616	*slot0 = INVALID_BEARER_ID;
 617	*slot1 = INVALID_BEARER_ID;
 618	for (i = 0; i < MAX_BEARERS; i++) {
 619		_l = n->links[i].link;
 620		if (!_l || !tipc_link_is_up(_l))
 621			continue;
 622		if (_l == l)
 623			continue;
 624		prio = tipc_link_prio(_l);
 625		if (prio < highest)
 626			continue;
 627		if (prio > highest) {
 628			highest = prio;
 629			*slot0 = i;
 630			*slot1 = i;
 631			continue;
 632		}
 633		*slot1 = i;
 634	}
 635
 636	if (!tipc_node_is_up(n)) {
 637		if (tipc_link_peer_is_down(l))
 638			tipc_node_fsm_evt(n, PEER_LOST_CONTACT_EVT);
 639		tipc_node_fsm_evt(n, SELF_LOST_CONTACT_EVT);
 640		tipc_link_fsm_evt(l, LINK_RESET_EVT);
 641		tipc_link_reset(l);
 642		tipc_link_build_reset_msg(l, xmitq);
 643		*maddr = &n->links[*bearer_id].maddr;
 644		node_lost_contact(n, &le->inputq);
 645		tipc_bcast_dec_bearer_dst_cnt(n->net, *bearer_id);
 646		return;
 647	}
 648	tipc_bcast_dec_bearer_dst_cnt(n->net, *bearer_id);
 649
 650	/* There is still a working link => initiate failover */
 651	*bearer_id = n->active_links[0];
 652	tnl = n->links[*bearer_id].link;
 653	tipc_link_fsm_evt(tnl, LINK_SYNCH_END_EVT);
 654	tipc_node_fsm_evt(n, NODE_SYNCH_END_EVT);
 655	n->sync_point = tipc_link_rcv_nxt(tnl) + (U16_MAX / 2 - 1);
 656	tipc_link_tnl_prepare(l, tnl, FAILOVER_MSG, xmitq);
 657	tipc_link_reset(l);
 658	tipc_link_fsm_evt(l, LINK_RESET_EVT);
 659	tipc_link_fsm_evt(l, LINK_FAILOVER_BEGIN_EVT);
 660	tipc_node_fsm_evt(n, NODE_FAILOVER_BEGIN_EVT);
 661	*maddr = &n->links[*bearer_id].maddr;
 662}
 663
 664static void tipc_node_link_down(struct tipc_node *n, int bearer_id, bool delete)
 665{
 666	struct tipc_link_entry *le = &n->links[bearer_id];
 667	struct tipc_link *l = le->link;
 668	struct tipc_media_addr *maddr;
 669	struct sk_buff_head xmitq;
 670
 671	if (!l)
 672		return;
 673
 674	__skb_queue_head_init(&xmitq);
 675
 676	tipc_node_write_lock(n);
 677	if (!tipc_link_is_establishing(l)) {
 678		__tipc_node_link_down(n, &bearer_id, &xmitq, &maddr);
 679		if (delete) {
 680			kfree(l);
 681			le->link = NULL;
 682			n->link_cnt--;
 683		}
 684	} else {
 685		/* Defuse pending tipc_node_link_up() */
 686		tipc_link_fsm_evt(l, LINK_RESET_EVT);
 687	}
 688	tipc_node_write_unlock(n);
 689	tipc_bearer_xmit(n->net, bearer_id, &xmitq, maddr);
 690	tipc_sk_rcv(n->net, &le->inputq);
 691}
 692
 693static bool tipc_node_is_up(struct tipc_node *n)
 694{
 695	return n->active_links[0] != INVALID_BEARER_ID;
 
 
 696}
 697
 698void tipc_node_check_dest(struct net *net, u32 onode,
 699			  struct tipc_bearer *b,
 700			  u16 capabilities, u32 signature,
 701			  struct tipc_media_addr *maddr,
 702			  bool *respond, bool *dupl_addr)
 703{
 704	struct tipc_node *n;
 705	struct tipc_link *l;
 706	struct tipc_link_entry *le;
 707	bool addr_match = false;
 708	bool sign_match = false;
 709	bool link_up = false;
 710	bool accept_addr = false;
 711	bool reset = true;
 712	char *if_name;
 713
 714	*dupl_addr = false;
 715	*respond = false;
 716
 717	n = tipc_node_create(net, onode, capabilities);
 718	if (!n)
 719		return;
 720
 721	tipc_node_write_lock(n);
 722
 723	le = &n->links[b->identity];
 724
 725	/* Prepare to validate requesting node's signature and media address */
 726	l = le->link;
 727	link_up = l && tipc_link_is_up(l);
 728	addr_match = l && !memcmp(&le->maddr, maddr, sizeof(*maddr));
 729	sign_match = (signature == n->signature);
 730
 731	/* These three flags give us eight permutations: */
 732
 733	if (sign_match && addr_match && link_up) {
 734		/* All is fine. Do nothing. */
 735		reset = false;
 736	} else if (sign_match && addr_match && !link_up) {
 737		/* Respond. The link will come up in due time */
 738		*respond = true;
 739	} else if (sign_match && !addr_match && link_up) {
 740		/* Peer has changed i/f address without rebooting.
 741		 * If so, the link will reset soon, and the next
 742		 * discovery will be accepted. So we can ignore it.
 743		 * It may also be an cloned or malicious peer having
 744		 * chosen the same node address and signature as an
 745		 * existing one.
 746		 * Ignore requests until the link goes down, if ever.
 747		 */
 748		*dupl_addr = true;
 749	} else if (sign_match && !addr_match && !link_up) {
 750		/* Peer link has changed i/f address without rebooting.
 751		 * It may also be a cloned or malicious peer; we can't
 752		 * distinguish between the two.
 753		 * The signature is correct, so we must accept.
 754		 */
 755		accept_addr = true;
 756		*respond = true;
 757	} else if (!sign_match && addr_match && link_up) {
 758		/* Peer node rebooted. Two possibilities:
 759		 *  - Delayed re-discovery; this link endpoint has already
 760		 *    reset and re-established contact with the peer, before
 761		 *    receiving a discovery message from that node.
 762		 *    (The peer happened to receive one from this node first).
 763		 *  - The peer came back so fast that our side has not
 764		 *    discovered it yet. Probing from this side will soon
 765		 *    reset the link, since there can be no working link
 766		 *    endpoint at the peer end, and the link will re-establish.
 767		 *  Accept the signature, since it comes from a known peer.
 768		 */
 769		n->signature = signature;
 770	} else if (!sign_match && addr_match && !link_up) {
 771		/*  The peer node has rebooted.
 772		 *  Accept signature, since it is a known peer.
 773		 */
 774		n->signature = signature;
 775		*respond = true;
 776	} else if (!sign_match && !addr_match && link_up) {
 777		/* Peer rebooted with new address, or a new/duplicate peer.
 778		 * Ignore until the link goes down, if ever.
 779		 */
 780		*dupl_addr = true;
 781	} else if (!sign_match && !addr_match && !link_up) {
 782		/* Peer rebooted with new address, or it is a new peer.
 783		 * Accept signature and address.
 784		 */
 785		n->signature = signature;
 786		accept_addr = true;
 787		*respond = true;
 788	}
 789
 790	if (!accept_addr)
 791		goto exit;
 792
 793	/* Now create new link if not already existing */
 794	if (!l) {
 795		if (n->link_cnt == 2) {
 796			pr_warn("Cannot establish 3rd link to %x\n", n->addr);
 797			goto exit;
 798		}
 799		if_name = strchr(b->name, ':') + 1;
 800		if (!tipc_link_create(net, if_name, b->identity, b->tolerance,
 801				      b->net_plane, b->mtu, b->priority,
 802				      b->window, mod(tipc_net(net)->random),
 803				      tipc_own_addr(net), onode,
 804				      n->capabilities,
 805				      tipc_bc_sndlink(n->net), n->bc_entry.link,
 806				      &le->inputq,
 807				      &n->bc_entry.namedq, &l)) {
 808			*respond = false;
 809			goto exit;
 810		}
 811		tipc_link_reset(l);
 812		tipc_link_fsm_evt(l, LINK_RESET_EVT);
 813		if (n->state == NODE_FAILINGOVER)
 814			tipc_link_fsm_evt(l, LINK_FAILOVER_BEGIN_EVT);
 815		le->link = l;
 816		n->link_cnt++;
 817		tipc_node_calculate_timer(n, l);
 818		if (n->link_cnt == 1)
 819			if (!mod_timer(&n->timer, jiffies + n->keepalive_intv))
 820				tipc_node_get(n);
 821	}
 822	memcpy(&le->maddr, maddr, sizeof(*maddr));
 823exit:
 824	tipc_node_write_unlock(n);
 825	if (reset && l && !tipc_link_is_reset(l))
 826		tipc_node_link_down(n, b->identity, false);
 827	tipc_node_put(n);
 828}
 829
 830void tipc_node_delete_links(struct net *net, int bearer_id)
 831{
 832	struct tipc_net *tn = net_generic(net, tipc_net_id);
 833	struct tipc_node *n;
 834
 835	rcu_read_lock();
 836	list_for_each_entry_rcu(n, &tn->node_list, list) {
 837		tipc_node_link_down(n, bearer_id, true);
 838	}
 839	rcu_read_unlock();
 840}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 841
 842static void tipc_node_reset_links(struct tipc_node *n)
 843{
 844	char addr_string[16];
 845	int i;
 846
 847	pr_warn("Resetting all links to %s\n",
 848		tipc_addr_string_fill(addr_string, n->addr));
 849
 850	for (i = 0; i < MAX_BEARERS; i++) {
 851		tipc_node_link_down(n, i, false);
 
 
 852	}
 853}
 854
 855/* tipc_node_fsm_evt - node finite state machine
 856 * Determines when contact is allowed with peer node
 857 */
 858static void tipc_node_fsm_evt(struct tipc_node *n, int evt)
 859{
 860	int state = n->state;
 861
 862	switch (state) {
 863	case SELF_DOWN_PEER_DOWN:
 864		switch (evt) {
 865		case SELF_ESTABL_CONTACT_EVT:
 866			state = SELF_UP_PEER_COMING;
 867			break;
 868		case PEER_ESTABL_CONTACT_EVT:
 869			state = SELF_COMING_PEER_UP;
 870			break;
 871		case SELF_LOST_CONTACT_EVT:
 872		case PEER_LOST_CONTACT_EVT:
 873			break;
 874		case NODE_SYNCH_END_EVT:
 875		case NODE_SYNCH_BEGIN_EVT:
 876		case NODE_FAILOVER_BEGIN_EVT:
 877		case NODE_FAILOVER_END_EVT:
 878		default:
 879			goto illegal_evt;
 880		}
 881		break;
 882	case SELF_UP_PEER_UP:
 883		switch (evt) {
 884		case SELF_LOST_CONTACT_EVT:
 885			state = SELF_DOWN_PEER_LEAVING;
 886			break;
 887		case PEER_LOST_CONTACT_EVT:
 888			state = SELF_LEAVING_PEER_DOWN;
 889			break;
 890		case NODE_SYNCH_BEGIN_EVT:
 891			state = NODE_SYNCHING;
 892			break;
 893		case NODE_FAILOVER_BEGIN_EVT:
 894			state = NODE_FAILINGOVER;
 895			break;
 896		case SELF_ESTABL_CONTACT_EVT:
 897		case PEER_ESTABL_CONTACT_EVT:
 898		case NODE_SYNCH_END_EVT:
 899		case NODE_FAILOVER_END_EVT:
 900			break;
 901		default:
 902			goto illegal_evt;
 903		}
 904		break;
 905	case SELF_DOWN_PEER_LEAVING:
 906		switch (evt) {
 907		case PEER_LOST_CONTACT_EVT:
 908			state = SELF_DOWN_PEER_DOWN;
 909			break;
 910		case SELF_ESTABL_CONTACT_EVT:
 911		case PEER_ESTABL_CONTACT_EVT:
 912		case SELF_LOST_CONTACT_EVT:
 913			break;
 914		case NODE_SYNCH_END_EVT:
 915		case NODE_SYNCH_BEGIN_EVT:
 916		case NODE_FAILOVER_BEGIN_EVT:
 917		case NODE_FAILOVER_END_EVT:
 918		default:
 919			goto illegal_evt;
 920		}
 921		break;
 922	case SELF_UP_PEER_COMING:
 923		switch (evt) {
 924		case PEER_ESTABL_CONTACT_EVT:
 925			state = SELF_UP_PEER_UP;
 926			break;
 927		case SELF_LOST_CONTACT_EVT:
 928			state = SELF_DOWN_PEER_LEAVING;
 929			break;
 930		case SELF_ESTABL_CONTACT_EVT:
 931		case PEER_LOST_CONTACT_EVT:
 932		case NODE_SYNCH_END_EVT:
 933		case NODE_FAILOVER_BEGIN_EVT:
 934			break;
 935		case NODE_SYNCH_BEGIN_EVT:
 936		case NODE_FAILOVER_END_EVT:
 937		default:
 938			goto illegal_evt;
 939		}
 940		break;
 941	case SELF_COMING_PEER_UP:
 942		switch (evt) {
 943		case SELF_ESTABL_CONTACT_EVT:
 944			state = SELF_UP_PEER_UP;
 945			break;
 946		case PEER_LOST_CONTACT_EVT:
 947			state = SELF_LEAVING_PEER_DOWN;
 948			break;
 949		case SELF_LOST_CONTACT_EVT:
 950		case PEER_ESTABL_CONTACT_EVT:
 951			break;
 952		case NODE_SYNCH_END_EVT:
 953		case NODE_SYNCH_BEGIN_EVT:
 954		case NODE_FAILOVER_BEGIN_EVT:
 955		case NODE_FAILOVER_END_EVT:
 956		default:
 957			goto illegal_evt;
 958		}
 959		break;
 960	case SELF_LEAVING_PEER_DOWN:
 961		switch (evt) {
 962		case SELF_LOST_CONTACT_EVT:
 963			state = SELF_DOWN_PEER_DOWN;
 964			break;
 965		case SELF_ESTABL_CONTACT_EVT:
 966		case PEER_ESTABL_CONTACT_EVT:
 967		case PEER_LOST_CONTACT_EVT:
 968			break;
 969		case NODE_SYNCH_END_EVT:
 970		case NODE_SYNCH_BEGIN_EVT:
 971		case NODE_FAILOVER_BEGIN_EVT:
 972		case NODE_FAILOVER_END_EVT:
 973		default:
 974			goto illegal_evt;
 975		}
 976		break;
 977	case NODE_FAILINGOVER:
 978		switch (evt) {
 979		case SELF_LOST_CONTACT_EVT:
 980			state = SELF_DOWN_PEER_LEAVING;
 981			break;
 982		case PEER_LOST_CONTACT_EVT:
 983			state = SELF_LEAVING_PEER_DOWN;
 984			break;
 985		case NODE_FAILOVER_END_EVT:
 986			state = SELF_UP_PEER_UP;
 987			break;
 988		case NODE_FAILOVER_BEGIN_EVT:
 989		case SELF_ESTABL_CONTACT_EVT:
 990		case PEER_ESTABL_CONTACT_EVT:
 991			break;
 992		case NODE_SYNCH_BEGIN_EVT:
 993		case NODE_SYNCH_END_EVT:
 994		default:
 995			goto illegal_evt;
 996		}
 997		break;
 998	case NODE_SYNCHING:
 999		switch (evt) {
1000		case SELF_LOST_CONTACT_EVT:
1001			state = SELF_DOWN_PEER_LEAVING;
1002			break;
1003		case PEER_LOST_CONTACT_EVT:
1004			state = SELF_LEAVING_PEER_DOWN;
1005			break;
1006		case NODE_SYNCH_END_EVT:
1007			state = SELF_UP_PEER_UP;
1008			break;
1009		case NODE_FAILOVER_BEGIN_EVT:
1010			state = NODE_FAILINGOVER;
1011			break;
1012		case NODE_SYNCH_BEGIN_EVT:
1013		case SELF_ESTABL_CONTACT_EVT:
1014		case PEER_ESTABL_CONTACT_EVT:
1015			break;
1016		case NODE_FAILOVER_END_EVT:
1017		default:
1018			goto illegal_evt;
1019		}
1020		break;
1021	default:
1022		pr_err("Unknown node fsm state %x\n", state);
1023		break;
1024	}
1025	n->state = state;
1026	return;
1027
1028illegal_evt:
1029	pr_err("Illegal node fsm evt %x in state %x\n", evt, state);
1030}
1031
1032static void node_lost_contact(struct tipc_node *n,
1033			      struct sk_buff_head *inputq)
1034{
1035	char addr_string[16];
1036	struct tipc_sock_conn *conn, *safe;
1037	struct tipc_link *l;
1038	struct list_head *conns = &n->conn_sks;
1039	struct sk_buff *skb;
1040	uint i;
1041
1042	pr_debug("Lost contact with %s\n",
1043		 tipc_addr_string_fill(addr_string, n->addr));
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1044
1045	/* Clean up broadcast state */
1046	tipc_bcast_remove_peer(n->net, n->bc_entry.link);
1047
1048	/* Abort any ongoing link failover */
1049	for (i = 0; i < MAX_BEARERS; i++) {
1050		l = n->links[i].link;
1051		if (l)
1052			tipc_link_fsm_evt(l, LINK_FAILOVER_END_EVT);
1053	}
1054
1055	/* Notify publications from this node */
1056	n->action_flags |= TIPC_NOTIFY_NODE_DOWN;
1057
1058	/* Notify sockets connected to node */
1059	list_for_each_entry_safe(conn, safe, conns, list) {
1060		skb = tipc_msg_create(TIPC_CRITICAL_IMPORTANCE, TIPC_CONN_MSG,
1061				      SHORT_H_SIZE, 0, tipc_own_addr(n->net),
1062				      conn->peer_node, conn->port,
1063				      conn->peer_port, TIPC_ERR_NO_NODE);
1064		if (likely(skb))
1065			skb_queue_tail(inputq, skb);
1066		list_del(&conn->list);
1067		kfree(conn);
1068	}
1069}
1070
1071/**
1072 * tipc_node_get_linkname - get the name of a link
1073 *
1074 * @bearer_id: id of the bearer
1075 * @node: peer node address
1076 * @linkname: link name output buffer
1077 *
1078 * Returns 0 on success
1079 */
1080int tipc_node_get_linkname(struct net *net, u32 bearer_id, u32 addr,
1081			   char *linkname, size_t len)
1082{
1083	struct tipc_link *link;
1084	int err = -EINVAL;
1085	struct tipc_node *node = tipc_node_find(net, addr);
1086
1087	if (!node)
1088		return err;
1089
1090	if (bearer_id >= MAX_BEARERS)
1091		goto exit;
1092
1093	tipc_node_read_lock(node);
1094	link = node->links[bearer_id].link;
1095	if (link) {
1096		strncpy(linkname, tipc_link_name(link), len);
1097		err = 0;
1098	}
1099exit:
1100	tipc_node_read_unlock(node);
1101	tipc_node_put(node);
1102	return err;
1103}
1104
1105/* Caller should hold node lock for the passed node */
1106static int __tipc_nl_add_node(struct tipc_nl_msg *msg, struct tipc_node *node)
1107{
1108	void *hdr;
1109	struct nlattr *attrs;
1110
1111	hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
1112			  NLM_F_MULTI, TIPC_NL_NODE_GET);
1113	if (!hdr)
1114		return -EMSGSIZE;
1115
1116	attrs = nla_nest_start(msg->skb, TIPC_NLA_NODE);
1117	if (!attrs)
1118		goto msg_full;
1119
1120	if (nla_put_u32(msg->skb, TIPC_NLA_NODE_ADDR, node->addr))
1121		goto attr_msg_full;
1122	if (tipc_node_is_up(node))
1123		if (nla_put_flag(msg->skb, TIPC_NLA_NODE_UP))
1124			goto attr_msg_full;
1125
1126	nla_nest_end(msg->skb, attrs);
1127	genlmsg_end(msg->skb, hdr);
1128
1129	return 0;
1130
1131attr_msg_full:
1132	nla_nest_cancel(msg->skb, attrs);
1133msg_full:
1134	genlmsg_cancel(msg->skb, hdr);
1135
1136	return -EMSGSIZE;
1137}
1138
1139/**
1140 * tipc_node_xmit() is the general link level function for message sending
1141 * @net: the applicable net namespace
1142 * @list: chain of buffers containing message
1143 * @dnode: address of destination node
1144 * @selector: a number used for deterministic link selection
1145 * Consumes the buffer chain, except when returning -ELINKCONG
1146 * Returns 0 if success, otherwise: -ELINKCONG,-EHOSTUNREACH,-EMSGSIZE,-ENOBUF
1147 */
1148int tipc_node_xmit(struct net *net, struct sk_buff_head *list,
1149		   u32 dnode, int selector)
1150{
1151	struct tipc_link_entry *le = NULL;
1152	struct tipc_node *n;
1153	struct sk_buff_head xmitq;
1154	int bearer_id;
1155	int rc;
1156
1157	if (in_own_node(net, dnode)) {
1158		tipc_sk_rcv(net, list);
1159		return 0;
1160	}
1161
1162	n = tipc_node_find(net, dnode);
1163	if (unlikely(!n)) {
1164		skb_queue_purge(list);
1165		return -EHOSTUNREACH;
1166	}
1167
1168	tipc_node_read_lock(n);
1169	bearer_id = n->active_links[selector & 1];
1170	if (unlikely(bearer_id == INVALID_BEARER_ID)) {
1171		tipc_node_read_unlock(n);
1172		tipc_node_put(n);
1173		skb_queue_purge(list);
1174		return -EHOSTUNREACH;
1175	}
1176
1177	__skb_queue_head_init(&xmitq);
1178	le = &n->links[bearer_id];
1179	spin_lock_bh(&le->lock);
1180	rc = tipc_link_xmit(le->link, list, &xmitq);
1181	spin_unlock_bh(&le->lock);
1182	tipc_node_read_unlock(n);
1183
1184	if (likely(rc == 0))
1185		tipc_bearer_xmit(net, bearer_id, &xmitq, &le->maddr);
1186	else if (rc == -ENOBUFS)
1187		tipc_node_link_down(n, bearer_id, false);
1188
1189	tipc_node_put(n);
1190
1191	return rc;
1192}
1193
1194/* tipc_node_xmit_skb(): send single buffer to destination
1195 * Buffers sent via this functon are generally TIPC_SYSTEM_IMPORTANCE
1196 * messages, which will not be rejected
1197 * The only exception is datagram messages rerouted after secondary
1198 * lookup, which are rare and safe to dispose of anyway.
1199 * TODO: Return real return value, and let callers use
1200 * tipc_wait_for_sendpkt() where applicable
1201 */
1202int tipc_node_xmit_skb(struct net *net, struct sk_buff *skb, u32 dnode,
1203		       u32 selector)
1204{
1205	struct sk_buff_head head;
1206	int rc;
1207
1208	skb_queue_head_init(&head);
1209	__skb_queue_tail(&head, skb);
1210	rc = tipc_node_xmit(net, &head, dnode, selector);
1211	if (rc == -ELINKCONG)
1212		kfree_skb(skb);
1213	return 0;
1214}
1215
1216void tipc_node_broadcast(struct net *net, struct sk_buff *skb)
1217{
1218	struct sk_buff *txskb;
1219	struct tipc_node *n;
1220	u32 dst;
1221
1222	rcu_read_lock();
1223	list_for_each_entry_rcu(n, tipc_nodes(net), list) {
1224		dst = n->addr;
1225		if (in_own_node(net, dst))
1226			continue;
1227		if (!tipc_node_is_up(n))
1228			continue;
1229		txskb = pskb_copy(skb, GFP_ATOMIC);
1230		if (!txskb)
1231			break;
1232		msg_set_destnode(buf_msg(txskb), dst);
1233		tipc_node_xmit_skb(net, txskb, dst, 0);
1234	}
1235	rcu_read_unlock();
1236
1237	kfree_skb(skb);
1238}
1239
1240/**
1241 * tipc_node_bc_rcv - process TIPC broadcast packet arriving from off-node
1242 * @net: the applicable net namespace
1243 * @skb: TIPC packet
1244 * @bearer_id: id of bearer message arrived on
1245 *
1246 * Invoked with no locks held.
1247 */
1248static void tipc_node_bc_rcv(struct net *net, struct sk_buff *skb, int bearer_id)
1249{
1250	int rc;
1251	struct sk_buff_head xmitq;
1252	struct tipc_bclink_entry *be;
1253	struct tipc_link_entry *le;
1254	struct tipc_msg *hdr = buf_msg(skb);
1255	int usr = msg_user(hdr);
1256	u32 dnode = msg_destnode(hdr);
1257	struct tipc_node *n;
1258
1259	__skb_queue_head_init(&xmitq);
1260
1261	/* If NACK for other node, let rcv link for that node peek into it */
1262	if ((usr == BCAST_PROTOCOL) && (dnode != tipc_own_addr(net)))
1263		n = tipc_node_find(net, dnode);
1264	else
1265		n = tipc_node_find(net, msg_prevnode(hdr));
1266	if (!n) {
1267		kfree_skb(skb);
1268		return;
1269	}
1270	be = &n->bc_entry;
1271	le = &n->links[bearer_id];
1272
1273	rc = tipc_bcast_rcv(net, be->link, skb);
1274
1275	/* Broadcast link reset may happen at reassembly failure */
1276	if (rc & TIPC_LINK_DOWN_EVT)
1277		tipc_node_reset_links(n);
1278
1279	/* Broadcast ACKs are sent on a unicast link */
1280	if (rc & TIPC_LINK_SND_BC_ACK) {
1281		tipc_node_read_lock(n);
1282		tipc_link_build_ack_msg(le->link, &xmitq);
1283		tipc_node_read_unlock(n);
1284	}
1285
1286	if (!skb_queue_empty(&xmitq))
1287		tipc_bearer_xmit(net, bearer_id, &xmitq, &le->maddr);
1288
1289	/* Deliver. 'arrvq' is under inputq2's lock protection */
1290	if (!skb_queue_empty(&be->inputq1)) {
1291		spin_lock_bh(&be->inputq2.lock);
1292		spin_lock_bh(&be->inputq1.lock);
1293		skb_queue_splice_tail_init(&be->inputq1, &be->arrvq);
1294		spin_unlock_bh(&be->inputq1.lock);
1295		spin_unlock_bh(&be->inputq2.lock);
1296		tipc_sk_mcast_rcv(net, &be->arrvq, &be->inputq2);
1297	}
1298	tipc_node_put(n);
1299}
1300
1301/**
1302 * tipc_node_check_state - check and if necessary update node state
1303 * @skb: TIPC packet
1304 * @bearer_id: identity of bearer delivering the packet
1305 * Returns true if state is ok, otherwise consumes buffer and returns false
1306 */
1307static bool tipc_node_check_state(struct tipc_node *n, struct sk_buff *skb,
1308				  int bearer_id, struct sk_buff_head *xmitq)
1309{
1310	struct tipc_msg *hdr = buf_msg(skb);
1311	int usr = msg_user(hdr);
1312	int mtyp = msg_type(hdr);
1313	u16 oseqno = msg_seqno(hdr);
1314	u16 iseqno = msg_seqno(msg_get_wrapped(hdr));
1315	u16 exp_pkts = msg_msgcnt(hdr);
1316	u16 rcv_nxt, syncpt, dlv_nxt, inputq_len;
1317	int state = n->state;
1318	struct tipc_link *l, *tnl, *pl = NULL;
1319	struct tipc_media_addr *maddr;
1320	int pb_id;
1321
1322	l = n->links[bearer_id].link;
1323	if (!l)
1324		return false;
1325	rcv_nxt = tipc_link_rcv_nxt(l);
1326
1327
1328	if (likely((state == SELF_UP_PEER_UP) && (usr != TUNNEL_PROTOCOL)))
1329		return true;
1330
1331	/* Find parallel link, if any */
1332	for (pb_id = 0; pb_id < MAX_BEARERS; pb_id++) {
1333		if ((pb_id != bearer_id) && n->links[pb_id].link) {
1334			pl = n->links[pb_id].link;
1335			break;
1336		}
1337	}
1338
1339	/* Check and update node accesibility if applicable */
1340	if (state == SELF_UP_PEER_COMING) {
1341		if (!tipc_link_is_up(l))
1342			return true;
1343		if (!msg_peer_link_is_up(hdr))
1344			return true;
1345		tipc_node_fsm_evt(n, PEER_ESTABL_CONTACT_EVT);
1346	}
1347
1348	if (state == SELF_DOWN_PEER_LEAVING) {
1349		if (msg_peer_node_is_up(hdr))
1350			return false;
1351		tipc_node_fsm_evt(n, PEER_LOST_CONTACT_EVT);
1352		return true;
1353	}
1354
1355	if (state == SELF_LEAVING_PEER_DOWN)
1356		return false;
1357
1358	/* Ignore duplicate packets */
1359	if ((usr != LINK_PROTOCOL) && less(oseqno, rcv_nxt))
1360		return true;
1361
1362	/* Initiate or update failover mode if applicable */
1363	if ((usr == TUNNEL_PROTOCOL) && (mtyp == FAILOVER_MSG)) {
1364		syncpt = oseqno + exp_pkts - 1;
1365		if (pl && tipc_link_is_up(pl)) {
1366			__tipc_node_link_down(n, &pb_id, xmitq, &maddr);
1367			tipc_skb_queue_splice_tail_init(tipc_link_inputq(pl),
1368							tipc_link_inputq(l));
1369		}
1370		/* If pkts arrive out of order, use lowest calculated syncpt */
1371		if (less(syncpt, n->sync_point))
1372			n->sync_point = syncpt;
1373	}
1374
1375	/* Open parallel link when tunnel link reaches synch point */
1376	if ((n->state == NODE_FAILINGOVER) && tipc_link_is_up(l)) {
1377		if (!more(rcv_nxt, n->sync_point))
1378			return true;
1379		tipc_node_fsm_evt(n, NODE_FAILOVER_END_EVT);
1380		if (pl)
1381			tipc_link_fsm_evt(pl, LINK_FAILOVER_END_EVT);
1382		return true;
1383	}
1384
1385	/* No synching needed if only one link */
1386	if (!pl || !tipc_link_is_up(pl))
1387		return true;
1388
1389	/* Initiate synch mode if applicable */
1390	if ((usr == TUNNEL_PROTOCOL) && (mtyp == SYNCH_MSG) && (oseqno == 1)) {
1391		syncpt = iseqno + exp_pkts - 1;
1392		if (!tipc_link_is_up(l)) {
1393			tipc_link_fsm_evt(l, LINK_ESTABLISH_EVT);
1394			__tipc_node_link_up(n, bearer_id, xmitq);
1395		}
1396		if (n->state == SELF_UP_PEER_UP) {
1397			n->sync_point = syncpt;
1398			tipc_link_fsm_evt(l, LINK_SYNCH_BEGIN_EVT);
1399			tipc_node_fsm_evt(n, NODE_SYNCH_BEGIN_EVT);
1400		}
1401	}
1402
1403	/* Open tunnel link when parallel link reaches synch point */
1404	if (n->state == NODE_SYNCHING) {
1405		if (tipc_link_is_synching(l)) {
1406			tnl = l;
1407		} else {
1408			tnl = pl;
1409			pl = l;
1410		}
1411		inputq_len = skb_queue_len(tipc_link_inputq(pl));
1412		dlv_nxt = tipc_link_rcv_nxt(pl) - inputq_len;
1413		if (more(dlv_nxt, n->sync_point)) {
1414			tipc_link_fsm_evt(tnl, LINK_SYNCH_END_EVT);
1415			tipc_node_fsm_evt(n, NODE_SYNCH_END_EVT);
1416			return true;
1417		}
1418		if (l == pl)
1419			return true;
1420		if ((usr == TUNNEL_PROTOCOL) && (mtyp == SYNCH_MSG))
1421			return true;
1422		if (usr == LINK_PROTOCOL)
1423			return true;
1424		return false;
1425	}
1426	return true;
1427}
1428
1429/**
1430 * tipc_rcv - process TIPC packets/messages arriving from off-node
1431 * @net: the applicable net namespace
1432 * @skb: TIPC packet
1433 * @bearer: pointer to bearer message arrived on
1434 *
1435 * Invoked with no locks held. Bearer pointer must point to a valid bearer
1436 * structure (i.e. cannot be NULL), but bearer can be inactive.
1437 */
1438void tipc_rcv(struct net *net, struct sk_buff *skb, struct tipc_bearer *b)
1439{
1440	struct sk_buff_head xmitq;
1441	struct tipc_node *n;
1442	struct tipc_msg *hdr = buf_msg(skb);
1443	int usr = msg_user(hdr);
1444	int bearer_id = b->identity;
1445	struct tipc_link_entry *le;
1446	u16 bc_ack = msg_bcast_ack(hdr);
1447	u32 self = tipc_own_addr(net);
1448	int rc = 0;
1449
1450	__skb_queue_head_init(&xmitq);
1451
1452	/* Ensure message is well-formed */
1453	if (unlikely(!tipc_msg_validate(skb)))
1454		goto discard;
1455
1456	/* Handle arrival of discovery or broadcast packet */
1457	if (unlikely(msg_non_seq(hdr))) {
1458		if (unlikely(usr == LINK_CONFIG))
1459			return tipc_disc_rcv(net, skb, b);
1460		else
1461			return tipc_node_bc_rcv(net, skb, bearer_id);
1462	}
1463
1464	/* Discard unicast link messages destined for another node */
1465	if (unlikely(!msg_short(hdr) && (msg_destnode(hdr) != self)))
1466		goto discard;
1467
1468	/* Locate neighboring node that sent packet */
1469	n = tipc_node_find(net, msg_prevnode(hdr));
1470	if (unlikely(!n))
1471		goto discard;
1472	le = &n->links[bearer_id];
1473
1474	/* Ensure broadcast reception is in synch with peer's send state */
1475	if (unlikely(usr == LINK_PROTOCOL))
1476		tipc_bcast_sync_rcv(net, n->bc_entry.link, hdr);
1477	else if (unlikely(tipc_link_acked(n->bc_entry.link) != bc_ack))
1478		tipc_bcast_ack_rcv(net, n->bc_entry.link, bc_ack);
1479
1480	/* Receive packet directly if conditions permit */
1481	tipc_node_read_lock(n);
1482	if (likely((n->state == SELF_UP_PEER_UP) && (usr != TUNNEL_PROTOCOL))) {
1483		spin_lock_bh(&le->lock);
1484		if (le->link) {
1485			rc = tipc_link_rcv(le->link, skb, &xmitq);
1486			skb = NULL;
1487		}
1488		spin_unlock_bh(&le->lock);
1489	}
1490	tipc_node_read_unlock(n);
1491
1492	/* Check/update node state before receiving */
1493	if (unlikely(skb)) {
1494		tipc_node_write_lock(n);
1495		if (tipc_node_check_state(n, skb, bearer_id, &xmitq)) {
1496			if (le->link) {
1497				rc = tipc_link_rcv(le->link, skb, &xmitq);
1498				skb = NULL;
1499			}
1500		}
1501		tipc_node_write_unlock(n);
1502	}
1503
1504	if (unlikely(rc & TIPC_LINK_UP_EVT))
1505		tipc_node_link_up(n, bearer_id, &xmitq);
1506
1507	if (unlikely(rc & TIPC_LINK_DOWN_EVT))
1508		tipc_node_link_down(n, bearer_id, false);
1509
1510	if (unlikely(!skb_queue_empty(&n->bc_entry.namedq)))
1511		tipc_named_rcv(net, &n->bc_entry.namedq);
1512
1513	if (!skb_queue_empty(&le->inputq))
1514		tipc_sk_rcv(net, &le->inputq);
1515
1516	if (!skb_queue_empty(&xmitq))
1517		tipc_bearer_xmit(net, bearer_id, &xmitq, &le->maddr);
1518
1519	tipc_node_put(n);
1520discard:
1521	kfree_skb(skb);
1522}
1523
1524int tipc_nl_node_dump(struct sk_buff *skb, struct netlink_callback *cb)
1525{
1526	int err;
1527	struct net *net = sock_net(skb->sk);
1528	struct tipc_net *tn = net_generic(net, tipc_net_id);
1529	int done = cb->args[0];
1530	int last_addr = cb->args[1];
1531	struct tipc_node *node;
1532	struct tipc_nl_msg msg;
1533
1534	if (done)
1535		return 0;
1536
1537	msg.skb = skb;
1538	msg.portid = NETLINK_CB(cb->skb).portid;
1539	msg.seq = cb->nlh->nlmsg_seq;
1540
1541	rcu_read_lock();
1542	if (last_addr) {
1543		node = tipc_node_find(net, last_addr);
1544		if (!node) {
1545			rcu_read_unlock();
1546			/* We never set seq or call nl_dump_check_consistent()
1547			 * this means that setting prev_seq here will cause the
1548			 * consistence check to fail in the netlink callback
1549			 * handler. Resulting in the NLMSG_DONE message having
1550			 * the NLM_F_DUMP_INTR flag set if the node state
1551			 * changed while we released the lock.
1552			 */
1553			cb->prev_seq = 1;
1554			return -EPIPE;
1555		}
1556		tipc_node_put(node);
1557	}
1558
1559	list_for_each_entry_rcu(node, &tn->node_list, list) {
1560		if (last_addr) {
1561			if (node->addr == last_addr)
1562				last_addr = 0;
1563			else
1564				continue;
1565		}
1566
1567		tipc_node_read_lock(node);
1568		err = __tipc_nl_add_node(&msg, node);
1569		if (err) {
1570			last_addr = node->addr;
1571			tipc_node_read_unlock(node);
1572			goto out;
1573		}
1574
1575		tipc_node_read_unlock(node);
1576	}
1577	done = 1;
1578out:
1579	cb->args[0] = done;
1580	cb->args[1] = last_addr;
1581	rcu_read_unlock();
1582
1583	return skb->len;
1584}
1585
1586/* tipc_node_find_by_name - locate owner node of link by link's name
1587 * @net: the applicable net namespace
1588 * @name: pointer to link name string
1589 * @bearer_id: pointer to index in 'node->links' array where the link was found.
1590 *
1591 * Returns pointer to node owning the link, or 0 if no matching link is found.
1592 */
1593static struct tipc_node *tipc_node_find_by_name(struct net *net,
1594						const char *link_name,
1595						unsigned int *bearer_id)
1596{
1597	struct tipc_net *tn = net_generic(net, tipc_net_id);
1598	struct tipc_link *l;
1599	struct tipc_node *n;
1600	struct tipc_node *found_node = NULL;
1601	int i;
1602
1603	*bearer_id = 0;
1604	rcu_read_lock();
1605	list_for_each_entry_rcu(n, &tn->node_list, list) {
1606		tipc_node_read_lock(n);
1607		for (i = 0; i < MAX_BEARERS; i++) {
1608			l = n->links[i].link;
1609			if (l && !strcmp(tipc_link_name(l), link_name)) {
1610				*bearer_id = i;
1611				found_node = n;
1612				break;
1613			}
1614		}
1615		tipc_node_read_unlock(n);
1616		if (found_node)
1617			break;
1618	}
1619	rcu_read_unlock();
1620
1621	return found_node;
 
1622}
1623
1624int tipc_nl_node_set_link(struct sk_buff *skb, struct genl_info *info)
1625{
1626	int err;
1627	int res = 0;
1628	int bearer_id;
1629	char *name;
1630	struct tipc_link *link;
1631	struct tipc_node *node;
1632	struct sk_buff_head xmitq;
1633	struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
1634	struct net *net = sock_net(skb->sk);
1635
1636	__skb_queue_head_init(&xmitq);
1637
1638	if (!info->attrs[TIPC_NLA_LINK])
1639		return -EINVAL;
1640
1641	err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
1642			       info->attrs[TIPC_NLA_LINK],
1643			       tipc_nl_link_policy);
1644	if (err)
1645		return err;
1646
1647	if (!attrs[TIPC_NLA_LINK_NAME])
1648		return -EINVAL;
1649
1650	name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
1651
1652	if (strcmp(name, tipc_bclink_name) == 0)
1653		return tipc_nl_bc_link_set(net, attrs);
1654
1655	node = tipc_node_find_by_name(net, name, &bearer_id);
1656	if (!node)
1657		return -EINVAL;
1658
1659	tipc_node_read_lock(node);
1660
1661	link = node->links[bearer_id].link;
1662	if (!link) {
1663		res = -EINVAL;
1664		goto out;
1665	}
1666
1667	if (attrs[TIPC_NLA_LINK_PROP]) {
1668		struct nlattr *props[TIPC_NLA_PROP_MAX + 1];
1669
1670		err = tipc_nl_parse_link_prop(attrs[TIPC_NLA_LINK_PROP],
1671					      props);
1672		if (err) {
1673			res = err;
1674			goto out;
1675		}
1676
1677		if (props[TIPC_NLA_PROP_TOL]) {
1678			u32 tol;
1679
1680			tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
1681			tipc_link_set_tolerance(link, tol, &xmitq);
1682		}
1683		if (props[TIPC_NLA_PROP_PRIO]) {
1684			u32 prio;
1685
1686			prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
1687			tipc_link_set_prio(link, prio, &xmitq);
1688		}
1689		if (props[TIPC_NLA_PROP_WIN]) {
1690			u32 win;
1691
1692			win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
1693			tipc_link_set_queue_limits(link, win);
1694		}
1695	}
1696
1697out:
1698	tipc_node_read_unlock(node);
1699	tipc_bearer_xmit(net, bearer_id, &xmitq, &node->links[bearer_id].maddr);
1700	return res;
1701}
1702
1703int tipc_nl_node_get_link(struct sk_buff *skb, struct genl_info *info)
1704{
1705	struct net *net = genl_info_net(info);
1706	struct tipc_nl_msg msg;
1707	char *name;
1708	int err;
1709
1710	msg.portid = info->snd_portid;
1711	msg.seq = info->snd_seq;
1712
1713	if (!info->attrs[TIPC_NLA_LINK_NAME])
1714		return -EINVAL;
1715	name = nla_data(info->attrs[TIPC_NLA_LINK_NAME]);
1716
1717	msg.skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
1718	if (!msg.skb)
1719		return -ENOMEM;
1720
1721	if (strcmp(name, tipc_bclink_name) == 0) {
1722		err = tipc_nl_add_bc_link(net, &msg);
1723		if (err) {
1724			nlmsg_free(msg.skb);
1725			return err;
1726		}
1727	} else {
1728		int bearer_id;
1729		struct tipc_node *node;
1730		struct tipc_link *link;
1731
1732		node = tipc_node_find_by_name(net, name, &bearer_id);
1733		if (!node)
1734			return -EINVAL;
1735
1736		tipc_node_read_lock(node);
1737		link = node->links[bearer_id].link;
1738		if (!link) {
1739			tipc_node_read_unlock(node);
1740			nlmsg_free(msg.skb);
1741			return -EINVAL;
1742		}
1743
1744		err = __tipc_nl_add_link(net, &msg, link, 0);
1745		tipc_node_read_unlock(node);
1746		if (err) {
1747			nlmsg_free(msg.skb);
1748			return err;
1749		}
1750	}
1751
1752	return genlmsg_reply(msg.skb, info);
1753}
1754
1755int tipc_nl_node_reset_link_stats(struct sk_buff *skb, struct genl_info *info)
1756{
1757	int err;
1758	char *link_name;
1759	unsigned int bearer_id;
1760	struct tipc_link *link;
1761	struct tipc_node *node;
1762	struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
1763	struct net *net = sock_net(skb->sk);
1764	struct tipc_link_entry *le;
1765
1766	if (!info->attrs[TIPC_NLA_LINK])
1767		return -EINVAL;
1768
1769	err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
1770			       info->attrs[TIPC_NLA_LINK],
1771			       tipc_nl_link_policy);
1772	if (err)
1773		return err;
1774
1775	if (!attrs[TIPC_NLA_LINK_NAME])
1776		return -EINVAL;
1777
1778	link_name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
1779
1780	if (strcmp(link_name, tipc_bclink_name) == 0) {
1781		err = tipc_bclink_reset_stats(net);
1782		if (err)
1783			return err;
1784		return 0;
1785	}
1786
1787	node = tipc_node_find_by_name(net, link_name, &bearer_id);
1788	if (!node)
1789		return -EINVAL;
1790
1791	le = &node->links[bearer_id];
1792	tipc_node_read_lock(node);
1793	spin_lock_bh(&le->lock);
1794	link = node->links[bearer_id].link;
1795	if (!link) {
1796		spin_unlock_bh(&le->lock);
1797		tipc_node_read_unlock(node);
1798		return -EINVAL;
1799	}
1800	tipc_link_reset_stats(link);
1801	spin_unlock_bh(&le->lock);
1802	tipc_node_read_unlock(node);
1803	return 0;
1804}
1805
1806/* Caller should hold node lock  */
1807static int __tipc_nl_add_node_links(struct net *net, struct tipc_nl_msg *msg,
1808				    struct tipc_node *node, u32 *prev_link)
1809{
1810	u32 i;
1811	int err;
1812
1813	for (i = *prev_link; i < MAX_BEARERS; i++) {
1814		*prev_link = i;
1815
1816		if (!node->links[i].link)
1817			continue;
1818
1819		err = __tipc_nl_add_link(net, msg,
1820					 node->links[i].link, NLM_F_MULTI);
1821		if (err)
1822			return err;
1823	}
1824	*prev_link = 0;
1825
1826	return 0;
1827}
1828
1829int tipc_nl_node_dump_link(struct sk_buff *skb, struct netlink_callback *cb)
1830{
1831	struct net *net = sock_net(skb->sk);
1832	struct tipc_net *tn = net_generic(net, tipc_net_id);
1833	struct tipc_node *node;
1834	struct tipc_nl_msg msg;
1835	u32 prev_node = cb->args[0];
1836	u32 prev_link = cb->args[1];
1837	int done = cb->args[2];
1838	int err;
1839
1840	if (done)
1841		return 0;
1842
1843	msg.skb = skb;
1844	msg.portid = NETLINK_CB(cb->skb).portid;
1845	msg.seq = cb->nlh->nlmsg_seq;
1846
1847	rcu_read_lock();
1848	if (prev_node) {
1849		node = tipc_node_find(net, prev_node);
1850		if (!node) {
1851			/* We never set seq or call nl_dump_check_consistent()
1852			 * this means that setting prev_seq here will cause the
1853			 * consistence check to fail in the netlink callback
1854			 * handler. Resulting in the last NLMSG_DONE message
1855			 * having the NLM_F_DUMP_INTR flag set.
1856			 */
1857			cb->prev_seq = 1;
1858			goto out;
1859		}
1860		tipc_node_put(node);
1861
1862		list_for_each_entry_continue_rcu(node, &tn->node_list,
1863						 list) {
1864			tipc_node_read_lock(node);
1865			err = __tipc_nl_add_node_links(net, &msg, node,
1866						       &prev_link);
1867			tipc_node_read_unlock(node);
1868			if (err)
1869				goto out;
1870
1871			prev_node = node->addr;
1872		}
1873	} else {
1874		err = tipc_nl_add_bc_link(net, &msg);
1875		if (err)
1876			goto out;
1877
1878		list_for_each_entry_rcu(node, &tn->node_list, list) {
1879			tipc_node_read_lock(node);
1880			err = __tipc_nl_add_node_links(net, &msg, node,
1881						       &prev_link);
1882			tipc_node_read_unlock(node);
1883			if (err)
1884				goto out;
1885
1886			prev_node = node->addr;
1887		}
 
1888	}
1889	done = 1;
1890out:
1891	rcu_read_unlock();
1892
1893	cb->args[0] = prev_node;
1894	cb->args[1] = prev_link;
1895	cb->args[2] = done;
1896
1897	return skb->len;
 
1898}