node.c revision 389dd9bcf65e10929cedfeb79c49bd02069b8899 
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
42#define NODE_HTABLE_SIZE 512
43
44static void node_lost_contact(struct tipc_node *n_ptr);
45static void node_established_contact(struct tipc_node *n_ptr);
46
47static DEFINE_SPINLOCK(node_create_lock);
48
49static struct hlist_head node_htable[NODE_HTABLE_SIZE];
50LIST_HEAD(tipc_node_list);
51static u32 tipc_num_nodes;
52
53static atomic_t tipc_num_links = ATOMIC_INIT(0);
54
55/*
56 * A trivial power-of-two bitmask technique is used for speed, since this
57 * operation is done for every incoming TIPC packet. The number of hash table
58 * entries has been chosen so that no hash chain exceeds 8 nodes and will
59 * usually be much smaller (typically only a single node).
60 */
61static unsigned int tipc_hashfn(u32 addr)
62{
63	return addr & (NODE_HTABLE_SIZE - 1);
64}
65
66/*
67 * tipc_node_find - locate specified node object, if it exists
68 */
69struct tipc_node *tipc_node_find(u32 addr)
70{
71	struct tipc_node *node;
72	struct hlist_node *pos;
73
74	if (unlikely(!in_own_cluster_exact(addr)))
75		return NULL;
76
77	hlist_for_each_entry(node, pos, &node_htable[tipc_hashfn(addr)], hash) {
78		if (node->addr == addr)
79			return node;
80	}
81	return NULL;
82}
83
84/**
85 * tipc_node_create - create neighboring node
86 *
87 * Currently, this routine is called by neighbor discovery code, which holds
88 * net_lock for reading only.  We must take node_create_lock to ensure a node
89 * isn't created twice if two different bearers discover the node at the same
90 * time.  (It would be preferable to switch to holding net_lock in write mode,
91 * but this is a non-trivial change.)
92 */
93struct tipc_node *tipc_node_create(u32 addr)
94{
95	struct tipc_node *n_ptr, *temp_node;
96
97	spin_lock_bh(&node_create_lock);
98
99	n_ptr = tipc_node_find(addr);
100	if (n_ptr) {
101		spin_unlock_bh(&node_create_lock);
102		return n_ptr;
103	}
104
105	n_ptr = kzalloc(sizeof(*n_ptr), GFP_ATOMIC);
106	if (!n_ptr) {
107		spin_unlock_bh(&node_create_lock);
108		pr_warn("Node creation failed, no memory\n");
109		return NULL;
110	}
111
112	n_ptr->addr = addr;
113	spin_lock_init(&n_ptr->lock);
114	INIT_HLIST_NODE(&n_ptr->hash);
115	INIT_LIST_HEAD(&n_ptr->list);
116	INIT_LIST_HEAD(&n_ptr->nsub);
117
118	hlist_add_head(&n_ptr->hash, &node_htable[tipc_hashfn(addr)]);
119
120	list_for_each_entry(temp_node, &tipc_node_list, list) {
121		if (n_ptr->addr < temp_node->addr)
122			break;
123	}
124	list_add_tail(&n_ptr->list, &temp_node->list);
125	n_ptr->block_setup = WAIT_PEER_DOWN;
126	n_ptr->signature = INVALID_NODE_SIG;
127
128	tipc_num_nodes++;
129
130	spin_unlock_bh(&node_create_lock);
131	return n_ptr;
132}
133
134void tipc_node_delete(struct tipc_node *n_ptr)
135{
136	list_del(&n_ptr->list);
137	hlist_del(&n_ptr->hash);
138	kfree(n_ptr);
139
140	tipc_num_nodes--;
141}
142
143/**
144 * tipc_node_link_up - handle addition of link
145 *
146 * Link becomes active (alone or shared) or standby, depending on its priority.
147 */
148void tipc_node_link_up(struct tipc_node *n_ptr, struct tipc_link *l_ptr)
149{
150	struct tipc_link **active = &n_ptr->active_links[0];
151
152	n_ptr->working_links++;
153
154	pr_info("Established link <%s> on network plane %c\n",
155		l_ptr->name, l_ptr->b_ptr->net_plane);
156
157	if (!active[0]) {
158		active[0] = active[1] = l_ptr;
159		node_established_contact(n_ptr);
160		return;
161	}
162	if (l_ptr->priority < active[0]->priority) {
163		pr_info("New link <%s> becomes standby\n", l_ptr->name);
164		return;
165	}
166	tipc_link_send_duplicate(active[0], l_ptr);
167	if (l_ptr->priority == active[0]->priority) {
168		active[0] = l_ptr;
169		return;
170	}
171	pr_info("Old link <%s> becomes standby\n", active[0]->name);
172	if (active[1] != active[0])
173		pr_info("Old link <%s> becomes standby\n", active[1]->name);
174	active[0] = active[1] = l_ptr;
175}
176
177/**
178 * node_select_active_links - select active link
179 */
180static void node_select_active_links(struct tipc_node *n_ptr)
181{
182	struct tipc_link **active = &n_ptr->active_links[0];
183	u32 i;
184	u32 highest_prio = 0;
185
186	active[0] = active[1] = NULL;
187
188	for (i = 0; i < MAX_BEARERS; i++) {
189		struct tipc_link *l_ptr = n_ptr->links[i];
190
191		if (!l_ptr || !tipc_link_is_up(l_ptr) ||
192		    (l_ptr->priority < highest_prio))
193			continue;
194
195		if (l_ptr->priority > highest_prio) {
196			highest_prio = l_ptr->priority;
197			active[0] = active[1] = l_ptr;
198		} else {
199			active[1] = l_ptr;
200		}
201	}
202}
203
204/**
205 * tipc_node_link_down - handle loss of link
206 */
207void tipc_node_link_down(struct tipc_node *n_ptr, struct tipc_link *l_ptr)
208{
209	struct tipc_link **active;
210
211	n_ptr->working_links--;
212
213	if (!tipc_link_is_active(l_ptr)) {
214		pr_info("Lost standby link <%s> on network plane %c\n",
215			l_ptr->name, l_ptr->b_ptr->net_plane);
216		return;
217	}
218	pr_info("Lost link <%s> on network plane %c\n",
219		l_ptr->name, l_ptr->b_ptr->net_plane);
220
221	active = &n_ptr->active_links[0];
222	if (active[0] == l_ptr)
223		active[0] = active[1];
224	if (active[1] == l_ptr)
225		active[1] = active[0];
226	if (active[0] == l_ptr)
227		node_select_active_links(n_ptr);
228	if (tipc_node_is_up(n_ptr))
229		tipc_link_changeover(l_ptr);
230	else
231		node_lost_contact(n_ptr);
232}
233
234int tipc_node_active_links(struct tipc_node *n_ptr)
235{
236	return n_ptr->active_links[0] != NULL;
237}
238
239int tipc_node_redundant_links(struct tipc_node *n_ptr)
240{
241	return n_ptr->working_links > 1;
242}
243
244int tipc_node_is_up(struct tipc_node *n_ptr)
245{
246	return tipc_node_active_links(n_ptr);
247}
248
249void tipc_node_attach_link(struct tipc_node *n_ptr, struct tipc_link *l_ptr)
250{
251	n_ptr->links[l_ptr->b_ptr->identity] = l_ptr;
252	atomic_inc(&tipc_num_links);
253	n_ptr->link_cnt++;
254}
255
256void tipc_node_detach_link(struct tipc_node *n_ptr, struct tipc_link *l_ptr)
257{
258	n_ptr->links[l_ptr->b_ptr->identity] = NULL;
259	atomic_dec(&tipc_num_links);
260	n_ptr->link_cnt--;
261}
262
263static void node_established_contact(struct tipc_node *n_ptr)
264{
265	tipc_k_signal((Handler)tipc_named_node_up, n_ptr->addr);
266
267	n_ptr->bclink.acked = tipc_bclink_get_last_sent();
268	tipc_bclink_add_node(n_ptr->addr);
269	n_ptr->bclink.recv_permitted = true;
270}
271
272static void node_name_purge_complete(unsigned long node_addr)
273{
274	struct tipc_node *n_ptr;
275
276	read_lock_bh(&tipc_net_lock);
277	n_ptr = tipc_node_find(node_addr);
278	if (n_ptr) {
279		tipc_node_lock(n_ptr);
280		n_ptr->block_setup &= ~WAIT_NAMES_GONE;
281		tipc_node_unlock(n_ptr);
282	}
283	read_unlock_bh(&tipc_net_lock);
284}
285
286static void node_lost_contact(struct tipc_node *n_ptr)
287{
288	char addr_string[16];
289	u32 i;
290
291	pr_info("Lost contact with %s\n",
292		tipc_addr_string_fill(addr_string, n_ptr->addr));
293
294	/* Flush broadcast link info associated with lost node */
295	if (n_ptr->bclink.recv_permitted) {
296		while (n_ptr->bclink.deferred_head) {
297			struct sk_buff *buf = n_ptr->bclink.deferred_head;
298			n_ptr->bclink.deferred_head = buf->next;
299			kfree_skb(buf);
300		}
301		n_ptr->bclink.deferred_size = 0;
302
303		if (n_ptr->bclink.defragm) {
304			kfree_skb(n_ptr->bclink.defragm);
305			n_ptr->bclink.defragm = NULL;
306		}
307
308		tipc_bclink_remove_node(n_ptr->addr);
309		tipc_bclink_acknowledge(n_ptr, INVALID_LINK_SEQ);
310
311		n_ptr->bclink.recv_permitted = false;
312	}
313
314	/* Abort link changeover */
315	for (i = 0; i < MAX_BEARERS; i++) {
316		struct tipc_link *l_ptr = n_ptr->links[i];
317		if (!l_ptr)
318			continue;
319		l_ptr->reset_checkpoint = l_ptr->next_in_no;
320		l_ptr->exp_msg_count = 0;
321		tipc_link_reset_fragments(l_ptr);
322	}
323
324	/* Notify subscribers */
325	tipc_nodesub_notify(n_ptr);
326
327	/* Prevent re-contact with node until cleanup is done */
328	n_ptr->block_setup = WAIT_PEER_DOWN | WAIT_NAMES_GONE;
329	tipc_k_signal((Handler)node_name_purge_complete, n_ptr->addr);
330}
331
332struct sk_buff *tipc_node_get_nodes(const void *req_tlv_area, int req_tlv_space)
333{
334	u32 domain;
335	struct sk_buff *buf;
336	struct tipc_node *n_ptr;
337	struct tipc_node_info node_info;
338	u32 payload_size;
339
340	if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_NET_ADDR))
341		return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
342
343	domain = ntohl(*(__be32 *)TLV_DATA(req_tlv_area));
344	if (!tipc_addr_domain_valid(domain))
345		return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
346						   " (network address)");
347
348	read_lock_bh(&tipc_net_lock);
349	if (!tipc_num_nodes) {
350		read_unlock_bh(&tipc_net_lock);
351		return tipc_cfg_reply_none();
352	}
353
354	/* For now, get space for all other nodes */
355	payload_size = TLV_SPACE(sizeof(node_info)) * tipc_num_nodes;
356	if (payload_size > 32768u) {
357		read_unlock_bh(&tipc_net_lock);
358		return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
359						   " (too many nodes)");
360	}
361	buf = tipc_cfg_reply_alloc(payload_size);
362	if (!buf) {
363		read_unlock_bh(&tipc_net_lock);
364		return NULL;
365	}
366
367	/* Add TLVs for all nodes in scope */
368	list_for_each_entry(n_ptr, &tipc_node_list, list) {
369		if (!tipc_in_scope(domain, n_ptr->addr))
370			continue;
371		node_info.addr = htonl(n_ptr->addr);
372		node_info.up = htonl(tipc_node_is_up(n_ptr));
373		tipc_cfg_append_tlv(buf, TIPC_TLV_NODE_INFO,
374				    &node_info, sizeof(node_info));
375	}
376
377	read_unlock_bh(&tipc_net_lock);
378	return buf;
379}
380
381struct sk_buff *tipc_node_get_links(const void *req_tlv_area, int req_tlv_space)
382{
383	u32 domain;
384	struct sk_buff *buf;
385	struct tipc_node *n_ptr;
386	struct tipc_link_info link_info;
387	u32 payload_size;
388
389	if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_NET_ADDR))
390		return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
391
392	domain = ntohl(*(__be32 *)TLV_DATA(req_tlv_area));
393	if (!tipc_addr_domain_valid(domain))
394		return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
395						   " (network address)");
396
397	if (!tipc_own_addr)
398		return tipc_cfg_reply_none();
399
400	read_lock_bh(&tipc_net_lock);
401
402	/* Get space for all unicast links + broadcast link */
403	payload_size = TLV_SPACE(sizeof(link_info)) *
404		(atomic_read(&tipc_num_links) + 1);
405	if (payload_size > 32768u) {
406		read_unlock_bh(&tipc_net_lock);
407		return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
408						   " (too many links)");
409	}
410	buf = tipc_cfg_reply_alloc(payload_size);
411	if (!buf) {
412		read_unlock_bh(&tipc_net_lock);
413		return NULL;
414	}
415
416	/* Add TLV for broadcast link */
417	link_info.dest = htonl(tipc_cluster_mask(tipc_own_addr));
418	link_info.up = htonl(1);
419	strlcpy(link_info.str, tipc_bclink_name, TIPC_MAX_LINK_NAME);
420	tipc_cfg_append_tlv(buf, TIPC_TLV_LINK_INFO, &link_info, sizeof(link_info));
421
422	/* Add TLVs for any other links in scope */
423	list_for_each_entry(n_ptr, &tipc_node_list, list) {
424		u32 i;
425
426		if (!tipc_in_scope(domain, n_ptr->addr))
427			continue;
428		tipc_node_lock(n_ptr);
429		for (i = 0; i < MAX_BEARERS; i++) {
430			if (!n_ptr->links[i])
431				continue;
432			link_info.dest = htonl(n_ptr->addr);
433			link_info.up = htonl(tipc_link_is_up(n_ptr->links[i]));
434			strcpy(link_info.str, n_ptr->links[i]->name);
435			tipc_cfg_append_tlv(buf, TIPC_TLV_LINK_INFO,
436					    &link_info, sizeof(link_info));
437		}
438		tipc_node_unlock(n_ptr);
439	}
440
441	read_unlock_bh(&tipc_net_lock);
442	return buf;
443}
444