1/*
   2 * net/tipc/node.c: TIPC node management routines
   3 *
   4 * Copyright (c) 2000-2006, 2012-2016, 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 "monitor.h"
  44#include "discover.h"
  45#include "netlink.h"
  46
  47#define INVALID_NODE_SIG	0x10000
  48
  49/* Flags used to take different actions according to flag type
  50 * TIPC_NOTIFY_NODE_DOWN: notify node is down
  51 * TIPC_NOTIFY_NODE_UP: notify node is up
  52 * TIPC_DISTRIBUTE_NAME: publish or withdraw link state name type
  53 */
  54enum {
  55	TIPC_NOTIFY_NODE_DOWN		= (1 << 3),
  56	TIPC_NOTIFY_NODE_UP		= (1 << 4),
  57	TIPC_NOTIFY_LINK_UP		= (1 << 6),
  58	TIPC_NOTIFY_LINK_DOWN		= (1 << 7)
  59};
  60
  61struct tipc_link_entry {
  62	struct tipc_link *link;
  63	spinlock_t lock; /* per link */
  64	u32 mtu;
  65	struct sk_buff_head inputq;
  66	struct tipc_media_addr maddr;
  67};
  68
  69struct tipc_bclink_entry {
  70	struct tipc_link *link;
  71	struct sk_buff_head inputq1;
  72	struct sk_buff_head arrvq;
  73	struct sk_buff_head inputq2;
  74	struct sk_buff_head namedq;
  75};
  76
  77/**
  78 * struct tipc_node - TIPC node structure
  79 * @addr: network address of node
  80 * @ref: reference counter to node object
  81 * @lock: rwlock governing access to structure
  82 * @net: the applicable net namespace
  83 * @hash: links to adjacent nodes in unsorted hash chain
  84 * @inputq: pointer to input queue containing messages for msg event
  85 * @namedq: pointer to name table input queue with name table messages
  86 * @active_links: bearer ids of active links, used as index into links[] array
  87 * @links: array containing references to all links to node
  88 * @action_flags: bit mask of different types of node actions
  89 * @state: connectivity state vs peer node
  90 * @sync_point: sequence number where synch/failover is finished
  91 * @list: links to adjacent nodes in sorted list of cluster's nodes
  92 * @working_links: number of working links to node (both active and standby)
  93 * @link_cnt: number of links to node
  94 * @capabilities: bitmap, indicating peer node's functional capabilities
  95 * @signature: node instance identifier
  96 * @link_id: local and remote bearer ids of changing link, if any
  97 * @publ_list: list of publications
  98 * @rcu: rcu struct for tipc_node
  99 */
 100struct tipc_node {
 101	u32 addr;
 102	struct kref kref;
 103	rwlock_t lock;
 104	struct net *net;
 105	struct hlist_node hash;
 106	int active_links[2];
 107	struct tipc_link_entry links[MAX_BEARERS];
 108	struct tipc_bclink_entry bc_entry;
 109	int action_flags;
 110	struct list_head list;
 111	int state;
 112	u16 sync_point;
 113	int link_cnt;
 114	u16 working_links;
 115	u16 capabilities;
 116	u32 signature;
 117	u32 link_id;
 118	struct list_head publ_list;
 119	struct list_head conn_sks;
 120	unsigned long keepalive_intv;
 121	struct timer_list timer;
 122	struct rcu_head rcu;
 123};
 124
 125/* Node FSM states and events:
 126 */
 127enum {
 128	SELF_DOWN_PEER_DOWN    = 0xdd,
 129	SELF_UP_PEER_UP        = 0xaa,
 130	SELF_DOWN_PEER_LEAVING = 0xd1,
 131	SELF_UP_PEER_COMING    = 0xac,
 132	SELF_COMING_PEER_UP    = 0xca,
 133	SELF_LEAVING_PEER_DOWN = 0x1d,
 134	NODE_FAILINGOVER       = 0xf0,
 135	NODE_SYNCHING          = 0xcc
 136};
 137
 138enum {
 139	SELF_ESTABL_CONTACT_EVT = 0xece,
 140	SELF_LOST_CONTACT_EVT   = 0x1ce,
 141	PEER_ESTABL_CONTACT_EVT = 0x9ece,
 142	PEER_LOST_CONTACT_EVT   = 0x91ce,
 143	NODE_FAILOVER_BEGIN_EVT = 0xfbe,
 144	NODE_FAILOVER_END_EVT   = 0xfee,
 145	NODE_SYNCH_BEGIN_EVT    = 0xcbe,
 146	NODE_SYNCH_END_EVT      = 0xcee
 147};
 148
 149static void __tipc_node_link_down(struct tipc_node *n, int *bearer_id,
 150				  struct sk_buff_head *xmitq,
 151				  struct tipc_media_addr **maddr);
 152static void tipc_node_link_down(struct tipc_node *n, int bearer_id,
 153				bool delete);
 154static void node_lost_contact(struct tipc_node *n, struct sk_buff_head *inputq);
 155static void tipc_node_delete(struct tipc_node *node);
 156static void tipc_node_timeout(unsigned long data);
 157static void tipc_node_fsm_evt(struct tipc_node *n, int evt);
 158static struct tipc_node *tipc_node_find(struct net *net, u32 addr);
 159static void tipc_node_put(struct tipc_node *node);
 160static bool tipc_node_is_up(struct tipc_node *n);
 161
 162struct tipc_sock_conn {
 163	u32 port;
 164	u32 peer_port;
 165	u32 peer_node;
 166	struct list_head list;
 167};
 168
 169static struct tipc_link *node_active_link(struct tipc_node *n, int sel)
 170{
 171	int bearer_id = n->active_links[sel & 1];
 172
 173	if (unlikely(bearer_id == INVALID_BEARER_ID))
 174		return NULL;
 175
 176	return n->links[bearer_id].link;
 177}
 178
 179int tipc_node_get_mtu(struct net *net, u32 addr, u32 sel)
 180{
 181	struct tipc_node *n;
 182	int bearer_id;
 183	unsigned int mtu = MAX_MSG_SIZE;
 184
 185	n = tipc_node_find(net, addr);
 186	if (unlikely(!n))
 187		return mtu;
 188
 189	bearer_id = n->active_links[sel & 1];
 190	if (likely(bearer_id != INVALID_BEARER_ID))
 191		mtu = n->links[bearer_id].mtu;
 192	tipc_node_put(n);
 193	return mtu;
 194}
 195
 196u16 tipc_node_get_capabilities(struct net *net, u32 addr)
 
 
 
 
 
 197{
 198	struct tipc_node *n;
 199	u16 caps;
 200
 201	n = tipc_node_find(net, addr);
 202	if (unlikely(!n))
 203		return TIPC_NODE_CAPABILITIES;
 204	caps = n->capabilities;
 205	tipc_node_put(n);
 206	return caps;
 207}
 208
 209static void tipc_node_kref_release(struct kref *kref)
 210{
 211	struct tipc_node *n = container_of(kref, struct tipc_node, kref);
 212
 213	kfree(n->bc_entry.link);
 214	kfree_rcu(n, rcu);
 215}
 216
 217static void tipc_node_put(struct tipc_node *node)
 218{
 219	kref_put(&node->kref, tipc_node_kref_release);
 220}
 221
 222static void tipc_node_get(struct tipc_node *node)
 223{
 224	kref_get(&node->kref);
 225}
 226
 227/*
 228 * tipc_node_find - locate specified node object, if it exists
 229 */
 230static struct tipc_node *tipc_node_find(struct net *net, u32 addr)
 231{
 232	struct tipc_net *tn = tipc_net(net);
 233	struct tipc_node *node;
 234	unsigned int thash = tipc_hashfn(addr);
 235
 236	if (unlikely(!in_own_cluster_exact(net, addr)))
 237		return NULL;
 238
 239	rcu_read_lock();
 240	hlist_for_each_entry_rcu(node, &tn->node_htable[thash], hash) {
 241		if (node->addr != addr)
 242			continue;
 243		if (!kref_get_unless_zero(&node->kref))
 244			node = NULL;
 245		break;
 246	}
 247	rcu_read_unlock();
 248	return node;
 249}
 250
 251static void tipc_node_read_lock(struct tipc_node *n)
 252{
 253	read_lock_bh(&n->lock);
 254}
 255
 256static void tipc_node_read_unlock(struct tipc_node *n)
 257{
 258	read_unlock_bh(&n->lock);
 259}
 260
 261static void tipc_node_write_lock(struct tipc_node *n)
 262{
 263	write_lock_bh(&n->lock);
 264}
 265
 266static void tipc_node_write_unlock_fast(struct tipc_node *n)
 267{
 268	write_unlock_bh(&n->lock);
 269}
 270
 271static void tipc_node_write_unlock(struct tipc_node *n)
 272{
 273	struct net *net = n->net;
 274	u32 addr = 0;
 275	u32 flags = n->action_flags;
 276	u32 link_id = 0;
 277	u32 bearer_id;
 278	struct list_head *publ_list;
 279
 280	if (likely(!flags)) {
 281		write_unlock_bh(&n->lock);
 282		return;
 283	}
 284
 285	addr = n->addr;
 286	link_id = n->link_id;
 287	bearer_id = link_id & 0xffff;
 288	publ_list = &n->publ_list;
 289
 290	n->action_flags &= ~(TIPC_NOTIFY_NODE_DOWN | TIPC_NOTIFY_NODE_UP |
 291			     TIPC_NOTIFY_LINK_DOWN | TIPC_NOTIFY_LINK_UP);
 292
 293	write_unlock_bh(&n->lock);
 294
 295	if (flags & TIPC_NOTIFY_NODE_DOWN)
 296		tipc_publ_notify(net, publ_list, addr);
 297
 298	if (flags & TIPC_NOTIFY_NODE_UP)
 299		tipc_named_node_up(net, addr);
 300
 301	if (flags & TIPC_NOTIFY_LINK_UP) {
 302		tipc_mon_peer_up(net, addr, bearer_id);
 303		tipc_nametbl_publish(net, TIPC_LINK_STATE, addr, addr,
 304				     TIPC_NODE_SCOPE, link_id, addr);
 305	}
 306	if (flags & TIPC_NOTIFY_LINK_DOWN) {
 307		tipc_mon_peer_down(net, addr, bearer_id);
 308		tipc_nametbl_withdraw(net, TIPC_LINK_STATE, addr,
 309				      link_id, addr);
 310	}
 311}
 312
 313struct tipc_node *tipc_node_create(struct net *net, u32 addr, u16 capabilities)
 314{
 315	struct tipc_net *tn = net_generic(net, tipc_net_id);
 316	struct tipc_node *n, *temp_node;
 317	int i;
 318
 319	spin_lock_bh(&tn->node_list_lock);
 320	n = tipc_node_find(net, addr);
 321	if (n) {
 322		/* Same node may come back with new capabilities */
 323		n->capabilities = capabilities;
 324		goto exit;
 325	}
 326	n = kzalloc(sizeof(*n), GFP_ATOMIC);
 327	if (!n) {
 328		pr_warn("Node creation failed, no memory\n");
 329		goto exit;
 330	}
 331	n->addr = addr;
 332	n->net = net;
 333	n->capabilities = capabilities;
 334	kref_init(&n->kref);
 335	rwlock_init(&n->lock);
 336	INIT_HLIST_NODE(&n->hash);
 337	INIT_LIST_HEAD(&n->list);
 338	INIT_LIST_HEAD(&n->publ_list);
 339	INIT_LIST_HEAD(&n->conn_sks);
 340	skb_queue_head_init(&n->bc_entry.namedq);
 341	skb_queue_head_init(&n->bc_entry.inputq1);
 342	__skb_queue_head_init(&n->bc_entry.arrvq);
 343	skb_queue_head_init(&n->bc_entry.inputq2);
 344	for (i = 0; i < MAX_BEARERS; i++)
 345		spin_lock_init(&n->links[i].lock);
 346	n->state = SELF_DOWN_PEER_LEAVING;
 347	n->signature = INVALID_NODE_SIG;
 348	n->active_links[0] = INVALID_BEARER_ID;
 349	n->active_links[1] = INVALID_BEARER_ID;
 350	if (!tipc_link_bc_create(net, tipc_own_addr(net), n->addr,
 351				 U16_MAX,
 352				 tipc_link_window(tipc_bc_sndlink(net)),
 353				 n->capabilities,
 354				 &n->bc_entry.inputq1,
 355				 &n->bc_entry.namedq,
 356				 tipc_bc_sndlink(net),
 357				 &n->bc_entry.link)) {
 358		pr_warn("Broadcast rcv link creation failed, no memory\n");
 359		kfree(n);
 360		n = NULL;
 361		goto exit;
 362	}
 363	tipc_node_get(n);
 364	setup_timer(&n->timer, tipc_node_timeout, (unsigned long)n);
 365	n->keepalive_intv = U32_MAX;
 366	hlist_add_head_rcu(&n->hash, &tn->node_htable[tipc_hashfn(addr)]);
 367	list_for_each_entry_rcu(temp_node, &tn->node_list, list) {
 368		if (n->addr < temp_node->addr)
 369			break;
 370	}
 371	list_add_tail_rcu(&n->list, &temp_node->list);
 372exit:
 373	spin_unlock_bh(&tn->node_list_lock);
 374	return n;
 375}
 376
 377static void tipc_node_calculate_timer(struct tipc_node *n, struct tipc_link *l)
 378{
 379	unsigned long tol = tipc_link_tolerance(l);
 380	unsigned long intv = ((tol / 4) > 500) ? 500 : tol / 4;
 
 381
 382	/* Link with lowest tolerance determines timer interval */
 383	if (intv < n->keepalive_intv)
 384		n->keepalive_intv = intv;
 385
 386	/* Ensure link's abort limit corresponds to current tolerance */
 387	tipc_link_set_abort_limit(l, tol / n->keepalive_intv);
 388}
 389
 390static void tipc_node_delete(struct tipc_node *node)
 391{
 392	list_del_rcu(&node->list);
 393	hlist_del_rcu(&node->hash);
 394	tipc_node_put(node);
 395
 396	del_timer_sync(&node->timer);
 397	tipc_node_put(node);
 398}
 399
 400void tipc_node_stop(struct net *net)
 401{
 402	struct tipc_net *tn = tipc_net(net);
 403	struct tipc_node *node, *t_node;
 404
 405	spin_lock_bh(&tn->node_list_lock);
 406	list_for_each_entry_safe(node, t_node, &tn->node_list, list)
 407		tipc_node_delete(node);
 408	spin_unlock_bh(&tn->node_list_lock);
 409}
 410
 411void tipc_node_subscribe(struct net *net, struct list_head *subscr, u32 addr)
 412{
 413	struct tipc_node *n;
 414
 415	if (in_own_node(net, addr))
 416		return;
 417
 418	n = tipc_node_find(net, addr);
 419	if (!n) {
 420		pr_warn("Node subscribe rejected, unknown node 0x%x\n", addr);
 421		return;
 422	}
 423	tipc_node_write_lock(n);
 424	list_add_tail(subscr, &n->publ_list);
 425	tipc_node_write_unlock_fast(n);
 426	tipc_node_put(n);
 427}
 428
 429void tipc_node_unsubscribe(struct net *net, struct list_head *subscr, u32 addr)
 430{
 431	struct tipc_node *n;
 432
 433	if (in_own_node(net, addr))
 434		return;
 435
 436	n = tipc_node_find(net, addr);
 437	if (!n) {
 438		pr_warn("Node unsubscribe rejected, unknown node 0x%x\n", addr);
 439		return;
 440	}
 441	tipc_node_write_lock(n);
 442	list_del_init(subscr);
 443	tipc_node_write_unlock_fast(n);
 444	tipc_node_put(n);
 445}
 446
 447int tipc_node_add_conn(struct net *net, u32 dnode, u32 port, u32 peer_port)
 448{
 449	struct tipc_node *node;
 450	struct tipc_sock_conn *conn;
 451	int err = 0;
 452
 453	if (in_own_node(net, dnode))
 454		return 0;
 455
 456	node = tipc_node_find(net, dnode);
 457	if (!node) {
 458		pr_warn("Connecting sock to node 0x%x failed\n", dnode);
 459		return -EHOSTUNREACH;
 460	}
 461	conn = kmalloc(sizeof(*conn), GFP_ATOMIC);
 462	if (!conn) {
 463		err = -EHOSTUNREACH;
 464		goto exit;
 465	}
 466	conn->peer_node = dnode;
 467	conn->port = port;
 468	conn->peer_port = peer_port;
 469
 470	tipc_node_write_lock(node);
 471	list_add_tail(&conn->list, &node->conn_sks);
 472	tipc_node_write_unlock(node);
 473exit:
 474	tipc_node_put(node);
 475	return err;
 476}
 477
 478void tipc_node_remove_conn(struct net *net, u32 dnode, u32 port)
 479{
 480	struct tipc_node *node;
 481	struct tipc_sock_conn *conn, *safe;
 482
 483	if (in_own_node(net, dnode))
 484		return;
 485
 486	node = tipc_node_find(net, dnode);
 487	if (!node)
 488		return;
 489
 490	tipc_node_write_lock(node);
 491	list_for_each_entry_safe(conn, safe, &node->conn_sks, list) {
 492		if (port != conn->port)
 493			continue;
 494		list_del(&conn->list);
 495		kfree(conn);
 496	}
 497	tipc_node_write_unlock(node);
 498	tipc_node_put(node);
 499}
 500
 501/* tipc_node_timeout - handle expiration of node timer
 502 */
 503static void tipc_node_timeout(unsigned long data)
 504{
 505	struct tipc_node *n = (struct tipc_node *)data;
 506	struct tipc_link_entry *le;
 507	struct sk_buff_head xmitq;
 508	int bearer_id;
 509	int rc = 0;
 510
 511	__skb_queue_head_init(&xmitq);
 512
 513	for (bearer_id = 0; bearer_id < MAX_BEARERS; bearer_id++) {
 514		tipc_node_read_lock(n);
 515		le = &n->links[bearer_id];
 516		spin_lock_bh(&le->lock);
 517		if (le->link) {
 518			/* Link tolerance may change asynchronously: */
 519			tipc_node_calculate_timer(n, le->link);
 520			rc = tipc_link_timeout(le->link, &xmitq);
 521		}
 522		spin_unlock_bh(&le->lock);
 523		tipc_node_read_unlock(n);
 524		tipc_bearer_xmit(n->net, bearer_id, &xmitq, &le->maddr);
 525		if (rc & TIPC_LINK_DOWN_EVT)
 526			tipc_node_link_down(n, bearer_id, false);
 527	}
 528	mod_timer(&n->timer, jiffies + msecs_to_jiffies(n->keepalive_intv));
 529}
 530
 531/**
 532 * __tipc_node_link_up - handle addition of link
 533 * Node lock must be held by caller
 534 * Link becomes active (alone or shared) or standby, depending on its priority.
 535 */
 536static void __tipc_node_link_up(struct tipc_node *n, int bearer_id,
 537				struct sk_buff_head *xmitq)
 538{
 539	int *slot0 = &n->active_links[0];
 540	int *slot1 = &n->active_links[1];
 541	struct tipc_link *ol = node_active_link(n, 0);
 542	struct tipc_link *nl = n->links[bearer_id].link;
 543
 544	if (!nl || tipc_link_is_up(nl))
 545		return;
 546
 547	tipc_link_fsm_evt(nl, LINK_ESTABLISH_EVT);
 548	if (!tipc_link_is_up(nl))
 549		return;
 550
 551	n->working_links++;
 552	n->action_flags |= TIPC_NOTIFY_LINK_UP;
 553	n->link_id = tipc_link_id(nl);
 554
 555	/* Leave room for tunnel header when returning 'mtu' to users: */
 556	n->links[bearer_id].mtu = tipc_link_mtu(nl) - INT_H_SIZE;
 557
 558	tipc_bearer_add_dest(n->net, bearer_id, n->addr);
 559	tipc_bcast_inc_bearer_dst_cnt(n->net, bearer_id);
 560
 561	pr_debug("Established link <%s> on network plane %c\n",
 562		 tipc_link_name(nl), tipc_link_plane(nl));
 563
 564	/* Ensure that a STATE message goes first */
 565	tipc_link_build_state_msg(nl, xmitq);
 566
 567	/* First link? => give it both slots */
 568	if (!ol) {
 569		*slot0 = bearer_id;
 570		*slot1 = bearer_id;
 571		tipc_node_fsm_evt(n, SELF_ESTABL_CONTACT_EVT);
 572		n->action_flags |= TIPC_NOTIFY_NODE_UP;
 573		tipc_link_set_active(nl, true);
 574		tipc_bcast_add_peer(n->net, nl, xmitq);
 575		return;
 576	}
 577
 578	/* Second link => redistribute slots */
 579	if (tipc_link_prio(nl) > tipc_link_prio(ol)) {
 580		pr_debug("Old link <%s> becomes standby\n", tipc_link_name(ol));
 581		*slot0 = bearer_id;
 582		*slot1 = bearer_id;
 583		tipc_link_set_active(nl, true);
 584		tipc_link_set_active(ol, false);
 585	} else if (tipc_link_prio(nl) == tipc_link_prio(ol)) {
 586		tipc_link_set_active(nl, true);
 587		*slot1 = bearer_id;
 588	} else {
 589		pr_debug("New link <%s> is standby\n", tipc_link_name(nl));
 590	}
 591
 592	/* Prepare synchronization with first link */
 593	tipc_link_tnl_prepare(ol, nl, SYNCH_MSG, xmitq);
 594}
 595
 596/**
 597 * tipc_node_link_up - handle addition of link
 598 *
 599 * Link becomes active (alone or shared) or standby, depending on its priority.
 600 */
 601static void tipc_node_link_up(struct tipc_node *n, int bearer_id,
 602			      struct sk_buff_head *xmitq)
 603{
 604	struct tipc_media_addr *maddr;
 605
 606	tipc_node_write_lock(n);
 607	__tipc_node_link_up(n, bearer_id, xmitq);
 608	maddr = &n->links[bearer_id].maddr;
 609	tipc_bearer_xmit(n->net, bearer_id, xmitq, maddr);
 610	tipc_node_write_unlock(n);
 611}
 612
 613/**
 614 * __tipc_node_link_down - handle loss of link
 615 */
 616static void __tipc_node_link_down(struct tipc_node *n, int *bearer_id,
 617				  struct sk_buff_head *xmitq,
 618				  struct tipc_media_addr **maddr)
 619{
 620	struct tipc_link_entry *le = &n->links[*bearer_id];
 621	int *slot0 = &n->active_links[0];
 622	int *slot1 = &n->active_links[1];
 623	int i, highest = 0, prio;
 624	struct tipc_link *l, *_l, *tnl;
 625
 626	l = n->links[*bearer_id].link;
 627	if (!l || tipc_link_is_reset(l))
 628		return;
 629
 630	n->working_links--;
 631	n->action_flags |= TIPC_NOTIFY_LINK_DOWN;
 632	n->link_id = tipc_link_id(l);
 633
 634	tipc_bearer_remove_dest(n->net, *bearer_id, n->addr);
 635
 636	pr_debug("Lost link <%s> on network plane %c\n",
 637		 tipc_link_name(l), tipc_link_plane(l));
 638
 639	/* Select new active link if any available */
 640	*slot0 = INVALID_BEARER_ID;
 641	*slot1 = INVALID_BEARER_ID;
 642	for (i = 0; i < MAX_BEARERS; i++) {
 643		_l = n->links[i].link;
 644		if (!_l || !tipc_link_is_up(_l))
 645			continue;
 646		if (_l == l)
 647			continue;
 648		prio = tipc_link_prio(_l);
 649		if (prio < highest)
 650			continue;
 651		if (prio > highest) {
 652			highest = prio;
 653			*slot0 = i;
 654			*slot1 = i;
 655			continue;
 656		}
 657		*slot1 = i;
 658	}
 659
 660	if (!tipc_node_is_up(n)) {
 661		if (tipc_link_peer_is_down(l))
 662			tipc_node_fsm_evt(n, PEER_LOST_CONTACT_EVT);
 663		tipc_node_fsm_evt(n, SELF_LOST_CONTACT_EVT);
 664		tipc_link_fsm_evt(l, LINK_RESET_EVT);
 665		tipc_link_reset(l);
 666		tipc_link_build_reset_msg(l, xmitq);
 667		*maddr = &n->links[*bearer_id].maddr;
 668		node_lost_contact(n, &le->inputq);
 669		tipc_bcast_dec_bearer_dst_cnt(n->net, *bearer_id);
 670		return;
 671	}
 672	tipc_bcast_dec_bearer_dst_cnt(n->net, *bearer_id);
 673
 674	/* There is still a working link => initiate failover */
 675	*bearer_id = n->active_links[0];
 676	tnl = n->links[*bearer_id].link;
 677	tipc_link_fsm_evt(tnl, LINK_SYNCH_END_EVT);
 678	tipc_node_fsm_evt(n, NODE_SYNCH_END_EVT);
 679	n->sync_point = tipc_link_rcv_nxt(tnl) + (U16_MAX / 2 - 1);
 680	tipc_link_tnl_prepare(l, tnl, FAILOVER_MSG, xmitq);
 681	tipc_link_reset(l);
 682	tipc_link_fsm_evt(l, LINK_RESET_EVT);
 683	tipc_link_fsm_evt(l, LINK_FAILOVER_BEGIN_EVT);
 684	tipc_node_fsm_evt(n, NODE_FAILOVER_BEGIN_EVT);
 685	*maddr = &n->links[*bearer_id].maddr;
 686}
 687
 688static void tipc_node_link_down(struct tipc_node *n, int bearer_id, bool delete)
 689{
 690	struct tipc_link_entry *le = &n->links[bearer_id];
 691	struct tipc_link *l = le->link;
 692	struct tipc_media_addr *maddr;
 693	struct sk_buff_head xmitq;
 694	int old_bearer_id = bearer_id;
 695
 696	if (!l)
 697		return;
 698
 699	__skb_queue_head_init(&xmitq);
 700
 701	tipc_node_write_lock(n);
 702	if (!tipc_link_is_establishing(l)) {
 703		__tipc_node_link_down(n, &bearer_id, &xmitq, &maddr);
 704		if (delete) {
 705			kfree(l);
 706			le->link = NULL;
 707			n->link_cnt--;
 708		}
 709	} else {
 710		/* Defuse pending tipc_node_link_up() */
 711		tipc_link_fsm_evt(l, LINK_RESET_EVT);
 712	}
 713	tipc_node_write_unlock(n);
 714	if (delete)
 715		tipc_mon_remove_peer(n->net, n->addr, old_bearer_id);
 716	tipc_bearer_xmit(n->net, bearer_id, &xmitq, maddr);
 717	tipc_sk_rcv(n->net, &le->inputq);
 718}
 719
 720static bool tipc_node_is_up(struct tipc_node *n)
 721{
 722	return n->active_links[0] != INVALID_BEARER_ID;
 723}
 724
 725void tipc_node_check_dest(struct net *net, u32 onode,
 726			  struct tipc_bearer *b,
 727			  u16 capabilities, u32 signature,
 728			  struct tipc_media_addr *maddr,
 729			  bool *respond, bool *dupl_addr)
 730{
 731	struct tipc_node *n;
 732	struct tipc_link *l;
 733	struct tipc_link_entry *le;
 734	bool addr_match = false;
 735	bool sign_match = false;
 736	bool link_up = false;
 737	bool accept_addr = false;
 738	bool reset = true;
 739	char *if_name;
 740	unsigned long intv;
 741
 742	*dupl_addr = false;
 743	*respond = false;
 744
 745	n = tipc_node_create(net, onode, capabilities);
 746	if (!n)
 747		return;
 748
 749	tipc_node_write_lock(n);
 750
 751	le = &n->links[b->identity];
 752
 753	/* Prepare to validate requesting node's signature and media address */
 754	l = le->link;
 755	link_up = l && tipc_link_is_up(l);
 756	addr_match = l && !memcmp(&le->maddr, maddr, sizeof(*maddr));
 757	sign_match = (signature == n->signature);
 758
 759	/* These three flags give us eight permutations: */
 760
 761	if (sign_match && addr_match && link_up) {
 762		/* All is fine. Do nothing. */
 763		reset = false;
 764	} else if (sign_match && addr_match && !link_up) {
 765		/* Respond. The link will come up in due time */
 766		*respond = true;
 767	} else if (sign_match && !addr_match && link_up) {
 768		/* Peer has changed i/f address without rebooting.
 769		 * If so, the link will reset soon, and the next
 770		 * discovery will be accepted. So we can ignore it.
 771		 * It may also be an cloned or malicious peer having
 772		 * chosen the same node address and signature as an
 773		 * existing one.
 774		 * Ignore requests until the link goes down, if ever.
 775		 */
 776		*dupl_addr = true;
 777	} else if (sign_match && !addr_match && !link_up) {
 778		/* Peer link has changed i/f address without rebooting.
 779		 * It may also be a cloned or malicious peer; we can't
 780		 * distinguish between the two.
 781		 * The signature is correct, so we must accept.
 782		 */
 783		accept_addr = true;
 784		*respond = true;
 785	} else if (!sign_match && addr_match && link_up) {
 786		/* Peer node rebooted. Two possibilities:
 787		 *  - Delayed re-discovery; this link endpoint has already
 788		 *    reset and re-established contact with the peer, before
 789		 *    receiving a discovery message from that node.
 790		 *    (The peer happened to receive one from this node first).
 791		 *  - The peer came back so fast that our side has not
 792		 *    discovered it yet. Probing from this side will soon
 793		 *    reset the link, since there can be no working link
 794		 *    endpoint at the peer end, and the link will re-establish.
 795		 *  Accept the signature, since it comes from a known peer.
 796		 */
 797		n->signature = signature;
 798	} else if (!sign_match && addr_match && !link_up) {
 799		/*  The peer node has rebooted.
 800		 *  Accept signature, since it is a known peer.
 801		 */
 802		n->signature = signature;
 803		*respond = true;
 804	} else if (!sign_match && !addr_match && link_up) {
 805		/* Peer rebooted with new address, or a new/duplicate peer.
 806		 * Ignore until the link goes down, if ever.
 807		 */
 808		*dupl_addr = true;
 809	} else if (!sign_match && !addr_match && !link_up) {
 810		/* Peer rebooted with new address, or it is a new peer.
 811		 * Accept signature and address.
 812		 */
 813		n->signature = signature;
 814		accept_addr = true;
 815		*respond = true;
 816	}
 817
 818	if (!accept_addr)
 819		goto exit;
 820
 821	/* Now create new link if not already existing */
 822	if (!l) {
 823		if (n->link_cnt == 2) {
 824			pr_warn("Cannot establish 3rd link to %x\n", n->addr);
 825			goto exit;
 826		}
 827		if_name = strchr(b->name, ':') + 1;
 828		if (!tipc_link_create(net, if_name, b->identity, b->tolerance,
 829				      b->net_plane, b->mtu, b->priority,
 830				      b->window, mod(tipc_net(net)->random),
 831				      tipc_own_addr(net), onode,
 832				      n->capabilities,
 833				      tipc_bc_sndlink(n->net), n->bc_entry.link,
 834				      &le->inputq,
 835				      &n->bc_entry.namedq, &l)) {
 836			*respond = false;
 837			goto exit;
 838		}
 839		tipc_link_reset(l);
 840		tipc_link_fsm_evt(l, LINK_RESET_EVT);
 841		if (n->state == NODE_FAILINGOVER)
 842			tipc_link_fsm_evt(l, LINK_FAILOVER_BEGIN_EVT);
 843		le->link = l;
 844		n->link_cnt++;
 845		tipc_node_calculate_timer(n, l);
 846		if (n->link_cnt == 1) {
 847			intv = jiffies + msecs_to_jiffies(n->keepalive_intv);
 848			if (!mod_timer(&n->timer, intv))
 849				tipc_node_get(n);
 850		}
 851	}
 852	memcpy(&le->maddr, maddr, sizeof(*maddr));
 853exit:
 854	tipc_node_write_unlock(n);
 855	if (reset && l && !tipc_link_is_reset(l))
 856		tipc_node_link_down(n, b->identity, false);
 857	tipc_node_put(n);
 858}
 859
 860void tipc_node_delete_links(struct net *net, int bearer_id)
 861{
 862	struct tipc_net *tn = net_generic(net, tipc_net_id);
 863	struct tipc_node *n;
 864
 865	rcu_read_lock();
 866	list_for_each_entry_rcu(n, &tn->node_list, list) {
 867		tipc_node_link_down(n, bearer_id, true);
 868	}
 869	rcu_read_unlock();
 870}
 871
 872static void tipc_node_reset_links(struct tipc_node *n)
 873{
 874	char addr_string[16];
 875	int i;
 876
 877	pr_warn("Resetting all links to %s\n",
 878		tipc_addr_string_fill(addr_string, n->addr));
 879
 880	for (i = 0; i < MAX_BEARERS; i++) {
 881		tipc_node_link_down(n, i, false);
 882	}
 883}
 884
 885/* tipc_node_fsm_evt - node finite state machine
 886 * Determines when contact is allowed with peer node
 887 */
 888static void tipc_node_fsm_evt(struct tipc_node *n, int evt)
 889{
 890	int state = n->state;
 891
 892	switch (state) {
 893	case SELF_DOWN_PEER_DOWN:
 894		switch (evt) {
 895		case SELF_ESTABL_CONTACT_EVT:
 896			state = SELF_UP_PEER_COMING;
 897			break;
 898		case PEER_ESTABL_CONTACT_EVT:
 899			state = SELF_COMING_PEER_UP;
 900			break;
 901		case SELF_LOST_CONTACT_EVT:
 902		case PEER_LOST_CONTACT_EVT:
 903			break;
 904		case NODE_SYNCH_END_EVT:
 905		case NODE_SYNCH_BEGIN_EVT:
 906		case NODE_FAILOVER_BEGIN_EVT:
 907		case NODE_FAILOVER_END_EVT:
 908		default:
 909			goto illegal_evt;
 910		}
 911		break;
 912	case SELF_UP_PEER_UP:
 913		switch (evt) {
 914		case SELF_LOST_CONTACT_EVT:
 915			state = SELF_DOWN_PEER_LEAVING;
 916			break;
 917		case PEER_LOST_CONTACT_EVT:
 918			state = SELF_LEAVING_PEER_DOWN;
 919			break;
 920		case NODE_SYNCH_BEGIN_EVT:
 921			state = NODE_SYNCHING;
 922			break;
 923		case NODE_FAILOVER_BEGIN_EVT:
 924			state = NODE_FAILINGOVER;
 925			break;
 926		case SELF_ESTABL_CONTACT_EVT:
 927		case PEER_ESTABL_CONTACT_EVT:
 928		case NODE_SYNCH_END_EVT:
 929		case NODE_FAILOVER_END_EVT:
 930			break;
 931		default:
 932			goto illegal_evt;
 933		}
 934		break;
 935	case SELF_DOWN_PEER_LEAVING:
 936		switch (evt) {
 937		case PEER_LOST_CONTACT_EVT:
 938			state = SELF_DOWN_PEER_DOWN;
 939			break;
 940		case SELF_ESTABL_CONTACT_EVT:
 941		case PEER_ESTABL_CONTACT_EVT:
 942		case SELF_LOST_CONTACT_EVT:
 943			break;
 944		case NODE_SYNCH_END_EVT:
 945		case NODE_SYNCH_BEGIN_EVT:
 946		case NODE_FAILOVER_BEGIN_EVT:
 947		case NODE_FAILOVER_END_EVT:
 948		default:
 949			goto illegal_evt;
 950		}
 951		break;
 952	case SELF_UP_PEER_COMING:
 953		switch (evt) {
 954		case PEER_ESTABL_CONTACT_EVT:
 955			state = SELF_UP_PEER_UP;
 956			break;
 957		case SELF_LOST_CONTACT_EVT:
 958			state = SELF_DOWN_PEER_DOWN;
 959			break;
 960		case SELF_ESTABL_CONTACT_EVT:
 961		case PEER_LOST_CONTACT_EVT:
 962		case NODE_SYNCH_END_EVT:
 963		case NODE_FAILOVER_BEGIN_EVT:
 964			break;
 965		case NODE_SYNCH_BEGIN_EVT:
 966		case NODE_FAILOVER_END_EVT:
 967		default:
 968			goto illegal_evt;
 969		}
 970		break;
 971	case SELF_COMING_PEER_UP:
 972		switch (evt) {
 973		case SELF_ESTABL_CONTACT_EVT:
 974			state = SELF_UP_PEER_UP;
 975			break;
 976		case PEER_LOST_CONTACT_EVT:
 977			state = SELF_DOWN_PEER_DOWN;
 978			break;
 979		case SELF_LOST_CONTACT_EVT:
 980		case PEER_ESTABL_CONTACT_EVT:
 981			break;
 982		case NODE_SYNCH_END_EVT:
 983		case NODE_SYNCH_BEGIN_EVT:
 984		case NODE_FAILOVER_BEGIN_EVT:
 985		case NODE_FAILOVER_END_EVT:
 986		default:
 987			goto illegal_evt;
 988		}
 989		break;
 990	case SELF_LEAVING_PEER_DOWN:
 991		switch (evt) {
 992		case SELF_LOST_CONTACT_EVT:
 993			state = SELF_DOWN_PEER_DOWN;
 994			break;
 995		case SELF_ESTABL_CONTACT_EVT:
 996		case PEER_ESTABL_CONTACT_EVT:
 997		case PEER_LOST_CONTACT_EVT:
 998			break;
 999		case NODE_SYNCH_END_EVT:
1000		case NODE_SYNCH_BEGIN_EVT:
1001		case NODE_FAILOVER_BEGIN_EVT:
1002		case NODE_FAILOVER_END_EVT:
1003		default:
1004			goto illegal_evt;
1005		}
1006		break;
1007	case NODE_FAILINGOVER:
1008		switch (evt) {
1009		case SELF_LOST_CONTACT_EVT:
1010			state = SELF_DOWN_PEER_LEAVING;
1011			break;
1012		case PEER_LOST_CONTACT_EVT:
1013			state = SELF_LEAVING_PEER_DOWN;
1014			break;
1015		case NODE_FAILOVER_END_EVT:
1016			state = SELF_UP_PEER_UP;
1017			break;
1018		case NODE_FAILOVER_BEGIN_EVT:
1019		case SELF_ESTABL_CONTACT_EVT:
1020		case PEER_ESTABL_CONTACT_EVT:
1021			break;
1022		case NODE_SYNCH_BEGIN_EVT:
1023		case NODE_SYNCH_END_EVT:
1024		default:
1025			goto illegal_evt;
1026		}
1027		break;
1028	case NODE_SYNCHING:
1029		switch (evt) {
1030		case SELF_LOST_CONTACT_EVT:
1031			state = SELF_DOWN_PEER_LEAVING;
1032			break;
1033		case PEER_LOST_CONTACT_EVT:
1034			state = SELF_LEAVING_PEER_DOWN;
1035			break;
1036		case NODE_SYNCH_END_EVT:
1037			state = SELF_UP_PEER_UP;
1038			break;
1039		case NODE_FAILOVER_BEGIN_EVT:
1040			state = NODE_FAILINGOVER;
1041			break;
1042		case NODE_SYNCH_BEGIN_EVT:
1043		case SELF_ESTABL_CONTACT_EVT:
1044		case PEER_ESTABL_CONTACT_EVT:
1045			break;
1046		case NODE_FAILOVER_END_EVT:
1047		default:
1048			goto illegal_evt;
1049		}
1050		break;
1051	default:
1052		pr_err("Unknown node fsm state %x\n", state);
1053		break;
1054	}
1055	n->state = state;
1056	return;
1057
1058illegal_evt:
1059	pr_err("Illegal node fsm evt %x in state %x\n", evt, state);
1060}
1061
1062static void node_lost_contact(struct tipc_node *n,
1063			      struct sk_buff_head *inputq)
1064{
1065	char addr_string[16];
1066	struct tipc_sock_conn *conn, *safe;
1067	struct tipc_link *l;
1068	struct list_head *conns = &n->conn_sks;
1069	struct sk_buff *skb;
1070	uint i;
1071
1072	pr_debug("Lost contact with %s\n",
1073		 tipc_addr_string_fill(addr_string, n->addr));
1074
1075	/* Clean up broadcast state */
1076	tipc_bcast_remove_peer(n->net, n->bc_entry.link);
1077
1078	/* Abort any ongoing link failover */
1079	for (i = 0; i < MAX_BEARERS; i++) {
1080		l = n->links[i].link;
1081		if (l)
1082			tipc_link_fsm_evt(l, LINK_FAILOVER_END_EVT);
1083	}
1084
1085	/* Notify publications from this node */
1086	n->action_flags |= TIPC_NOTIFY_NODE_DOWN;
1087
1088	/* Notify sockets connected to node */
1089	list_for_each_entry_safe(conn, safe, conns, list) {
1090		skb = tipc_msg_create(TIPC_CRITICAL_IMPORTANCE, TIPC_CONN_MSG,
1091				      SHORT_H_SIZE, 0, tipc_own_addr(n->net),
1092				      conn->peer_node, conn->port,
1093				      conn->peer_port, TIPC_ERR_NO_NODE);
1094		if (likely(skb))
1095			skb_queue_tail(inputq, skb);
1096		list_del(&conn->list);
1097		kfree(conn);
1098	}
1099}
1100
1101/**
1102 * tipc_node_get_linkname - get the name of a link
1103 *
1104 * @bearer_id: id of the bearer
1105 * @node: peer node address
1106 * @linkname: link name output buffer
1107 *
1108 * Returns 0 on success
1109 */
1110int tipc_node_get_linkname(struct net *net, u32 bearer_id, u32 addr,
1111			   char *linkname, size_t len)
1112{
1113	struct tipc_link *link;
1114	int err = -EINVAL;
1115	struct tipc_node *node = tipc_node_find(net, addr);
1116
1117	if (!node)
1118		return err;
1119
1120	if (bearer_id >= MAX_BEARERS)
1121		goto exit;
1122
1123	tipc_node_read_lock(node);
1124	link = node->links[bearer_id].link;
1125	if (link) {
1126		strncpy(linkname, tipc_link_name(link), len);
1127		err = 0;
1128	}
1129exit:
1130	tipc_node_read_unlock(node);
1131	tipc_node_put(node);
1132	return err;
1133}
1134
1135/* Caller should hold node lock for the passed node */
1136static int __tipc_nl_add_node(struct tipc_nl_msg *msg, struct tipc_node *node)
1137{
1138	void *hdr;
1139	struct nlattr *attrs;
1140
1141	hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
1142			  NLM_F_MULTI, TIPC_NL_NODE_GET);
1143	if (!hdr)
1144		return -EMSGSIZE;
1145
1146	attrs = nla_nest_start(msg->skb, TIPC_NLA_NODE);
1147	if (!attrs)
1148		goto msg_full;
1149
1150	if (nla_put_u32(msg->skb, TIPC_NLA_NODE_ADDR, node->addr))
1151		goto attr_msg_full;
1152	if (tipc_node_is_up(node))
1153		if (nla_put_flag(msg->skb, TIPC_NLA_NODE_UP))
1154			goto attr_msg_full;
1155
1156	nla_nest_end(msg->skb, attrs);
1157	genlmsg_end(msg->skb, hdr);
1158
1159	return 0;
1160
1161attr_msg_full:
1162	nla_nest_cancel(msg->skb, attrs);
1163msg_full:
1164	genlmsg_cancel(msg->skb, hdr);
1165
1166	return -EMSGSIZE;
1167}
1168
1169/**
1170 * tipc_node_xmit() is the general link level function for message sending
1171 * @net: the applicable net namespace
1172 * @list: chain of buffers containing message
1173 * @dnode: address of destination node
1174 * @selector: a number used for deterministic link selection
1175 * Consumes the buffer chain, except when returning -ELINKCONG
1176 * Returns 0 if success, otherwise: -ELINKCONG,-EHOSTUNREACH,-EMSGSIZE,-ENOBUF
1177 */
1178int tipc_node_xmit(struct net *net, struct sk_buff_head *list,
1179		   u32 dnode, int selector)
1180{
1181	struct tipc_link_entry *le = NULL;
1182	struct tipc_node *n;
1183	struct sk_buff_head xmitq;
1184	int bearer_id;
1185	int rc;
1186
1187	if (in_own_node(net, dnode)) {
1188		tipc_sk_rcv(net, list);
1189		return 0;
1190	}
1191
1192	n = tipc_node_find(net, dnode);
1193	if (unlikely(!n)) {
1194		skb_queue_purge(list);
1195		return -EHOSTUNREACH;
1196	}
1197
1198	tipc_node_read_lock(n);
1199	bearer_id = n->active_links[selector & 1];
1200	if (unlikely(bearer_id == INVALID_BEARER_ID)) {
1201		tipc_node_read_unlock(n);
1202		tipc_node_put(n);
1203		skb_queue_purge(list);
1204		return -EHOSTUNREACH;
1205	}
1206
1207	__skb_queue_head_init(&xmitq);
1208	le = &n->links[bearer_id];
1209	spin_lock_bh(&le->lock);
1210	rc = tipc_link_xmit(le->link, list, &xmitq);
1211	spin_unlock_bh(&le->lock);
1212	tipc_node_read_unlock(n);
1213
1214	if (likely(rc == 0))
1215		tipc_bearer_xmit(net, bearer_id, &xmitq, &le->maddr);
1216	else if (rc == -ENOBUFS)
1217		tipc_node_link_down(n, bearer_id, false);
1218
1219	tipc_node_put(n);
1220
1221	return rc;
1222}
1223
1224/* tipc_node_xmit_skb(): send single buffer to destination
1225 * Buffers sent via this functon are generally TIPC_SYSTEM_IMPORTANCE
1226 * messages, which will not be rejected
1227 * The only exception is datagram messages rerouted after secondary
1228 * lookup, which are rare and safe to dispose of anyway.
1229 * TODO: Return real return value, and let callers use
1230 * tipc_wait_for_sendpkt() where applicable
1231 */
1232int tipc_node_xmit_skb(struct net *net, struct sk_buff *skb, u32 dnode,
1233		       u32 selector)
1234{
1235	struct sk_buff_head head;
1236	int rc;
1237
1238	skb_queue_head_init(&head);
1239	__skb_queue_tail(&head, skb);
1240	rc = tipc_node_xmit(net, &head, dnode, selector);
1241	if (rc == -ELINKCONG)
1242		kfree_skb(skb);
1243	return 0;
1244}
1245
1246void tipc_node_broadcast(struct net *net, struct sk_buff *skb)
1247{
1248	struct sk_buff *txskb;
1249	struct tipc_node *n;
1250	u32 dst;
1251
1252	rcu_read_lock();
1253	list_for_each_entry_rcu(n, tipc_nodes(net), list) {
1254		dst = n->addr;
1255		if (in_own_node(net, dst))
1256			continue;
1257		if (!tipc_node_is_up(n))
1258			continue;
1259		txskb = pskb_copy(skb, GFP_ATOMIC);
1260		if (!txskb)
1261			break;
1262		msg_set_destnode(buf_msg(txskb), dst);
1263		tipc_node_xmit_skb(net, txskb, dst, 0);
1264	}
1265	rcu_read_unlock();
1266
1267	kfree_skb(skb);
1268}
1269
1270static void tipc_node_bc_sync_rcv(struct tipc_node *n, struct tipc_msg *hdr,
1271				  int bearer_id, struct sk_buff_head *xmitq)
1272{
1273	struct tipc_link *ucl;
1274	int rc;
1275
1276	rc = tipc_bcast_sync_rcv(n->net, n->bc_entry.link, hdr);
1277
1278	if (rc & TIPC_LINK_DOWN_EVT) {
1279		tipc_bearer_reset_all(n->net);
1280		return;
1281	}
1282
1283	if (!(rc & TIPC_LINK_SND_STATE))
1284		return;
1285
1286	/* If probe message, a STATE response will be sent anyway */
1287	if (msg_probe(hdr))
1288		return;
1289
1290	/* Produce a STATE message carrying broadcast NACK */
1291	tipc_node_read_lock(n);
1292	ucl = n->links[bearer_id].link;
1293	if (ucl)
1294		tipc_link_build_state_msg(ucl, xmitq);
1295	tipc_node_read_unlock(n);
1296}
1297
1298/**
1299 * tipc_node_bc_rcv - process TIPC broadcast packet arriving from off-node
1300 * @net: the applicable net namespace
1301 * @skb: TIPC packet
1302 * @bearer_id: id of bearer message arrived on
1303 *
1304 * Invoked with no locks held.
1305 */
1306static void tipc_node_bc_rcv(struct net *net, struct sk_buff *skb, int bearer_id)
1307{
1308	int rc;
1309	struct sk_buff_head xmitq;
1310	struct tipc_bclink_entry *be;
1311	struct tipc_link_entry *le;
1312	struct tipc_msg *hdr = buf_msg(skb);
1313	int usr = msg_user(hdr);
1314	u32 dnode = msg_destnode(hdr);
1315	struct tipc_node *n;
1316
1317	__skb_queue_head_init(&xmitq);
1318
1319	/* If NACK for other node, let rcv link for that node peek into it */
1320	if ((usr == BCAST_PROTOCOL) && (dnode != tipc_own_addr(net)))
1321		n = tipc_node_find(net, dnode);
1322	else
1323		n = tipc_node_find(net, msg_prevnode(hdr));
1324	if (!n) {
1325		kfree_skb(skb);
1326		return;
1327	}
1328	be = &n->bc_entry;
1329	le = &n->links[bearer_id];
1330
1331	rc = tipc_bcast_rcv(net, be->link, skb);
1332
 
 
 
 
1333	/* Broadcast ACKs are sent on a unicast link */
1334	if (rc & TIPC_LINK_SND_STATE) {
1335		tipc_node_read_lock(n);
1336		tipc_link_build_state_msg(le->link, &xmitq);
1337		tipc_node_read_unlock(n);
1338	}
1339
1340	if (!skb_queue_empty(&xmitq))
1341		tipc_bearer_xmit(net, bearer_id, &xmitq, &le->maddr);
1342
1343	/* Deliver. 'arrvq' is under inputq2's lock protection */
1344	if (!skb_queue_empty(&be->inputq1)) {
1345		spin_lock_bh(&be->inputq2.lock);
1346		spin_lock_bh(&be->inputq1.lock);
1347		skb_queue_splice_tail_init(&be->inputq1, &be->arrvq);
1348		spin_unlock_bh(&be->inputq1.lock);
1349		spin_unlock_bh(&be->inputq2.lock);
1350		tipc_sk_mcast_rcv(net, &be->arrvq, &be->inputq2);
1351	}
1352
1353	if (rc & TIPC_LINK_DOWN_EVT) {
1354		/* Reception reassembly failure => reset all links to peer */
1355		if (!tipc_link_is_up(be->link))
1356			tipc_node_reset_links(n);
1357
1358		/* Retransmission failure => reset all links to all peers */
1359		if (!tipc_link_is_up(tipc_bc_sndlink(net)))
1360			tipc_bearer_reset_all(net);
1361	}
1362
1363	tipc_node_put(n);
1364}
1365
1366/**
1367 * tipc_node_check_state - check and if necessary update node state
1368 * @skb: TIPC packet
1369 * @bearer_id: identity of bearer delivering the packet
1370 * Returns true if state is ok, otherwise consumes buffer and returns false
1371 */
1372static bool tipc_node_check_state(struct tipc_node *n, struct sk_buff *skb,
1373				  int bearer_id, struct sk_buff_head *xmitq)
1374{
1375	struct tipc_msg *hdr = buf_msg(skb);
1376	int usr = msg_user(hdr);
1377	int mtyp = msg_type(hdr);
1378	u16 oseqno = msg_seqno(hdr);
1379	u16 iseqno = msg_seqno(msg_get_wrapped(hdr));
1380	u16 exp_pkts = msg_msgcnt(hdr);
1381	u16 rcv_nxt, syncpt, dlv_nxt, inputq_len;
1382	int state = n->state;
1383	struct tipc_link *l, *tnl, *pl = NULL;
1384	struct tipc_media_addr *maddr;
1385	int pb_id;
1386
1387	l = n->links[bearer_id].link;
1388	if (!l)
1389		return false;
1390	rcv_nxt = tipc_link_rcv_nxt(l);
1391
1392
1393	if (likely((state == SELF_UP_PEER_UP) && (usr != TUNNEL_PROTOCOL)))
1394		return true;
1395
1396	/* Find parallel link, if any */
1397	for (pb_id = 0; pb_id < MAX_BEARERS; pb_id++) {
1398		if ((pb_id != bearer_id) && n->links[pb_id].link) {
1399			pl = n->links[pb_id].link;
1400			break;
1401		}
1402	}
1403
1404	/* Check and update node accesibility if applicable */
1405	if (state == SELF_UP_PEER_COMING) {
1406		if (!tipc_link_is_up(l))
1407			return true;
1408		if (!msg_peer_link_is_up(hdr))
1409			return true;
1410		tipc_node_fsm_evt(n, PEER_ESTABL_CONTACT_EVT);
1411	}
1412
1413	if (state == SELF_DOWN_PEER_LEAVING) {
1414		if (msg_peer_node_is_up(hdr))
1415			return false;
1416		tipc_node_fsm_evt(n, PEER_LOST_CONTACT_EVT);
1417		return true;
1418	}
1419
1420	if (state == SELF_LEAVING_PEER_DOWN)
1421		return false;
1422
1423	/* Ignore duplicate packets */
1424	if ((usr != LINK_PROTOCOL) && less(oseqno, rcv_nxt))
1425		return true;
1426
1427	/* Initiate or update failover mode if applicable */
1428	if ((usr == TUNNEL_PROTOCOL) && (mtyp == FAILOVER_MSG)) {
1429		syncpt = oseqno + exp_pkts - 1;
1430		if (pl && tipc_link_is_up(pl)) {
1431			__tipc_node_link_down(n, &pb_id, xmitq, &maddr);
1432			tipc_skb_queue_splice_tail_init(tipc_link_inputq(pl),
1433							tipc_link_inputq(l));
1434		}
1435		/* If pkts arrive out of order, use lowest calculated syncpt */
1436		if (less(syncpt, n->sync_point))
1437			n->sync_point = syncpt;
1438	}
1439
1440	/* Open parallel link when tunnel link reaches synch point */
1441	if ((n->state == NODE_FAILINGOVER) && tipc_link_is_up(l)) {
1442		if (!more(rcv_nxt, n->sync_point))
1443			return true;
1444		tipc_node_fsm_evt(n, NODE_FAILOVER_END_EVT);
1445		if (pl)
1446			tipc_link_fsm_evt(pl, LINK_FAILOVER_END_EVT);
1447		return true;
1448	}
1449
1450	/* No synching needed if only one link */
1451	if (!pl || !tipc_link_is_up(pl))
1452		return true;
1453
1454	/* Initiate synch mode if applicable */
1455	if ((usr == TUNNEL_PROTOCOL) && (mtyp == SYNCH_MSG) && (oseqno == 1)) {
1456		syncpt = iseqno + exp_pkts - 1;
1457		if (!tipc_link_is_up(l)) {
1458			tipc_link_fsm_evt(l, LINK_ESTABLISH_EVT);
1459			__tipc_node_link_up(n, bearer_id, xmitq);
1460		}
1461		if (n->state == SELF_UP_PEER_UP) {
1462			n->sync_point = syncpt;
1463			tipc_link_fsm_evt(l, LINK_SYNCH_BEGIN_EVT);
1464			tipc_node_fsm_evt(n, NODE_SYNCH_BEGIN_EVT);
1465		}
1466	}
1467
1468	/* Open tunnel link when parallel link reaches synch point */
1469	if (n->state == NODE_SYNCHING) {
1470		if (tipc_link_is_synching(l)) {
1471			tnl = l;
1472		} else {
1473			tnl = pl;
1474			pl = l;
1475		}
1476		inputq_len = skb_queue_len(tipc_link_inputq(pl));
1477		dlv_nxt = tipc_link_rcv_nxt(pl) - inputq_len;
1478		if (more(dlv_nxt, n->sync_point)) {
1479			tipc_link_fsm_evt(tnl, LINK_SYNCH_END_EVT);
1480			tipc_node_fsm_evt(n, NODE_SYNCH_END_EVT);
1481			return true;
1482		}
1483		if (l == pl)
1484			return true;
1485		if ((usr == TUNNEL_PROTOCOL) && (mtyp == SYNCH_MSG))
1486			return true;
1487		if (usr == LINK_PROTOCOL)
1488			return true;
1489		return false;
1490	}
1491	return true;
1492}
1493
1494/**
1495 * tipc_rcv - process TIPC packets/messages arriving from off-node
1496 * @net: the applicable net namespace
1497 * @skb: TIPC packet
1498 * @bearer: pointer to bearer message arrived on
1499 *
1500 * Invoked with no locks held. Bearer pointer must point to a valid bearer
1501 * structure (i.e. cannot be NULL), but bearer can be inactive.
1502 */
1503void tipc_rcv(struct net *net, struct sk_buff *skb, struct tipc_bearer *b)
1504{
1505	struct sk_buff_head xmitq;
1506	struct tipc_node *n;
1507	struct tipc_msg *hdr = buf_msg(skb);
1508	int usr = msg_user(hdr);
1509	int bearer_id = b->identity;
1510	struct tipc_link_entry *le;
1511	u16 bc_ack = msg_bcast_ack(hdr);
1512	u32 self = tipc_own_addr(net);
1513	int rc = 0;
1514
1515	__skb_queue_head_init(&xmitq);
1516
1517	/* Ensure message is well-formed */
1518	if (unlikely(!tipc_msg_validate(skb)))
1519		goto discard;
1520
1521	/* Handle arrival of discovery or broadcast packet */
1522	if (unlikely(msg_non_seq(hdr))) {
1523		if (unlikely(usr == LINK_CONFIG))
1524			return tipc_disc_rcv(net, skb, b);
1525		else
1526			return tipc_node_bc_rcv(net, skb, bearer_id);
1527	}
1528
1529	/* Discard unicast link messages destined for another node */
1530	if (unlikely(!msg_short(hdr) && (msg_destnode(hdr) != self)))
1531		goto discard;
1532
1533	/* Locate neighboring node that sent packet */
1534	n = tipc_node_find(net, msg_prevnode(hdr));
1535	if (unlikely(!n))
1536		goto discard;
1537	le = &n->links[bearer_id];
1538
1539	/* Ensure broadcast reception is in synch with peer's send state */
1540	if (unlikely(usr == LINK_PROTOCOL))
1541		tipc_node_bc_sync_rcv(n, hdr, bearer_id, &xmitq);
1542	else if (unlikely(tipc_link_acked(n->bc_entry.link) != bc_ack))
1543		tipc_bcast_ack_rcv(net, n->bc_entry.link, hdr);
1544
1545	/* Receive packet directly if conditions permit */
1546	tipc_node_read_lock(n);
1547	if (likely((n->state == SELF_UP_PEER_UP) && (usr != TUNNEL_PROTOCOL))) {
1548		spin_lock_bh(&le->lock);
1549		if (le->link) {
1550			rc = tipc_link_rcv(le->link, skb, &xmitq);
1551			skb = NULL;
1552		}
1553		spin_unlock_bh(&le->lock);
1554	}
1555	tipc_node_read_unlock(n);
1556
1557	/* Check/update node state before receiving */
1558	if (unlikely(skb)) {
1559		tipc_node_write_lock(n);
1560		if (tipc_node_check_state(n, skb, bearer_id, &xmitq)) {
1561			if (le->link) {
1562				rc = tipc_link_rcv(le->link, skb, &xmitq);
1563				skb = NULL;
1564			}
1565		}
1566		tipc_node_write_unlock(n);
1567	}
1568
1569	if (unlikely(rc & TIPC_LINK_UP_EVT))
1570		tipc_node_link_up(n, bearer_id, &xmitq);
1571
1572	if (unlikely(rc & TIPC_LINK_DOWN_EVT))
1573		tipc_node_link_down(n, bearer_id, false);
1574
1575	if (unlikely(!skb_queue_empty(&n->bc_entry.namedq)))
1576		tipc_named_rcv(net, &n->bc_entry.namedq);
1577
1578	if (!skb_queue_empty(&le->inputq))
1579		tipc_sk_rcv(net, &le->inputq);
1580
1581	if (!skb_queue_empty(&xmitq))
1582		tipc_bearer_xmit(net, bearer_id, &xmitq, &le->maddr);
1583
1584	tipc_node_put(n);
1585discard:
1586	kfree_skb(skb);
1587}
1588
1589int tipc_nl_peer_rm(struct sk_buff *skb, struct genl_info *info)
1590{
1591	struct net *net = sock_net(skb->sk);
1592	struct tipc_net *tn = net_generic(net, tipc_net_id);
1593	struct nlattr *attrs[TIPC_NLA_NET_MAX + 1];
1594	struct tipc_node *peer;
1595	u32 addr;
1596	int err;
1597	int i;
1598
1599	/* We identify the peer by its net */
1600	if (!info->attrs[TIPC_NLA_NET])
1601		return -EINVAL;
1602
1603	err = nla_parse_nested(attrs, TIPC_NLA_NET_MAX,
1604			       info->attrs[TIPC_NLA_NET],
1605			       tipc_nl_net_policy);
1606	if (err)
1607		return err;
1608
1609	if (!attrs[TIPC_NLA_NET_ADDR])
1610		return -EINVAL;
1611
1612	addr = nla_get_u32(attrs[TIPC_NLA_NET_ADDR]);
1613
1614	if (in_own_node(net, addr))
1615		return -ENOTSUPP;
1616
1617	spin_lock_bh(&tn->node_list_lock);
1618	peer = tipc_node_find(net, addr);
1619	if (!peer) {
1620		spin_unlock_bh(&tn->node_list_lock);
1621		return -ENXIO;
1622	}
1623
1624	tipc_node_write_lock(peer);
1625	if (peer->state != SELF_DOWN_PEER_DOWN &&
1626	    peer->state != SELF_DOWN_PEER_LEAVING) {
1627		tipc_node_write_unlock(peer);
1628		err = -EBUSY;
1629		goto err_out;
1630	}
1631
1632	for (i = 0; i < MAX_BEARERS; i++) {
1633		struct tipc_link_entry *le = &peer->links[i];
1634
1635		if (le->link) {
1636			kfree(le->link);
1637			le->link = NULL;
1638			peer->link_cnt--;
1639		}
1640	}
1641	tipc_node_write_unlock(peer);
1642	tipc_node_delete(peer);
1643
1644	err = 0;
1645err_out:
1646	tipc_node_put(peer);
1647	spin_unlock_bh(&tn->node_list_lock);
1648
1649	return err;
1650}
1651
1652int tipc_nl_node_dump(struct sk_buff *skb, struct netlink_callback *cb)
1653{
1654	int err;
1655	struct net *net = sock_net(skb->sk);
1656	struct tipc_net *tn = net_generic(net, tipc_net_id);
1657	int done = cb->args[0];
1658	int last_addr = cb->args[1];
1659	struct tipc_node *node;
1660	struct tipc_nl_msg msg;
1661
1662	if (done)
1663		return 0;
1664
1665	msg.skb = skb;
1666	msg.portid = NETLINK_CB(cb->skb).portid;
1667	msg.seq = cb->nlh->nlmsg_seq;
1668
1669	rcu_read_lock();
1670	if (last_addr) {
1671		node = tipc_node_find(net, last_addr);
1672		if (!node) {
1673			rcu_read_unlock();
1674			/* We never set seq or call nl_dump_check_consistent()
1675			 * this means that setting prev_seq here will cause the
1676			 * consistence check to fail in the netlink callback
1677			 * handler. Resulting in the NLMSG_DONE message having
1678			 * the NLM_F_DUMP_INTR flag set if the node state
1679			 * changed while we released the lock.
1680			 */
1681			cb->prev_seq = 1;
1682			return -EPIPE;
1683		}
1684		tipc_node_put(node);
1685	}
1686
1687	list_for_each_entry_rcu(node, &tn->node_list, list) {
1688		if (last_addr) {
1689			if (node->addr == last_addr)
1690				last_addr = 0;
1691			else
1692				continue;
1693		}
1694
1695		tipc_node_read_lock(node);
1696		err = __tipc_nl_add_node(&msg, node);
1697		if (err) {
1698			last_addr = node->addr;
1699			tipc_node_read_unlock(node);
1700			goto out;
1701		}
1702
1703		tipc_node_read_unlock(node);
1704	}
1705	done = 1;
1706out:
1707	cb->args[0] = done;
1708	cb->args[1] = last_addr;
1709	rcu_read_unlock();
1710
1711	return skb->len;
1712}
1713
1714/* tipc_node_find_by_name - locate owner node of link by link's name
1715 * @net: the applicable net namespace
1716 * @name: pointer to link name string
1717 * @bearer_id: pointer to index in 'node->links' array where the link was found.
1718 *
1719 * Returns pointer to node owning the link, or 0 if no matching link is found.
1720 */
1721static struct tipc_node *tipc_node_find_by_name(struct net *net,
1722						const char *link_name,
1723						unsigned int *bearer_id)
1724{
1725	struct tipc_net *tn = net_generic(net, tipc_net_id);
1726	struct tipc_link *l;
1727	struct tipc_node *n;
1728	struct tipc_node *found_node = NULL;
1729	int i;
1730
1731	*bearer_id = 0;
1732	rcu_read_lock();
1733	list_for_each_entry_rcu(n, &tn->node_list, list) {
1734		tipc_node_read_lock(n);
1735		for (i = 0; i < MAX_BEARERS; i++) {
1736			l = n->links[i].link;
1737			if (l && !strcmp(tipc_link_name(l), link_name)) {
1738				*bearer_id = i;
1739				found_node = n;
1740				break;
1741			}
1742		}
1743		tipc_node_read_unlock(n);
1744		if (found_node)
1745			break;
1746	}
1747	rcu_read_unlock();
1748
1749	return found_node;
1750}
1751
1752int tipc_nl_node_set_link(struct sk_buff *skb, struct genl_info *info)
1753{
1754	int err;
1755	int res = 0;
1756	int bearer_id;
1757	char *name;
1758	struct tipc_link *link;
1759	struct tipc_node *node;
1760	struct sk_buff_head xmitq;
1761	struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
1762	struct net *net = sock_net(skb->sk);
1763
1764	__skb_queue_head_init(&xmitq);
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	name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
1779
1780	if (strcmp(name, tipc_bclink_name) == 0)
1781		return tipc_nl_bc_link_set(net, attrs);
1782
1783	node = tipc_node_find_by_name(net, name, &bearer_id);
1784	if (!node)
1785		return -EINVAL;
1786
1787	tipc_node_read_lock(node);
1788
1789	link = node->links[bearer_id].link;
1790	if (!link) {
1791		res = -EINVAL;
1792		goto out;
1793	}
1794
1795	if (attrs[TIPC_NLA_LINK_PROP]) {
1796		struct nlattr *props[TIPC_NLA_PROP_MAX + 1];
1797
1798		err = tipc_nl_parse_link_prop(attrs[TIPC_NLA_LINK_PROP],
1799					      props);
1800		if (err) {
1801			res = err;
1802			goto out;
1803		}
1804
1805		if (props[TIPC_NLA_PROP_TOL]) {
1806			u32 tol;
1807
1808			tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
1809			tipc_link_set_tolerance(link, tol, &xmitq);
1810		}
1811		if (props[TIPC_NLA_PROP_PRIO]) {
1812			u32 prio;
1813
1814			prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
1815			tipc_link_set_prio(link, prio, &xmitq);
1816		}
1817		if (props[TIPC_NLA_PROP_WIN]) {
1818			u32 win;
1819
1820			win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
1821			tipc_link_set_queue_limits(link, win);
1822		}
1823	}
1824
1825out:
1826	tipc_node_read_unlock(node);
1827	tipc_bearer_xmit(net, bearer_id, &xmitq, &node->links[bearer_id].maddr);
1828	return res;
1829}
1830
1831int tipc_nl_node_get_link(struct sk_buff *skb, struct genl_info *info)
1832{
1833	struct net *net = genl_info_net(info);
1834	struct tipc_nl_msg msg;
1835	char *name;
1836	int err;
1837
1838	msg.portid = info->snd_portid;
1839	msg.seq = info->snd_seq;
1840
1841	if (!info->attrs[TIPC_NLA_LINK_NAME])
1842		return -EINVAL;
1843	name = nla_data(info->attrs[TIPC_NLA_LINK_NAME]);
1844
1845	msg.skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
1846	if (!msg.skb)
1847		return -ENOMEM;
1848
1849	if (strcmp(name, tipc_bclink_name) == 0) {
1850		err = tipc_nl_add_bc_link(net, &msg);
1851		if (err) {
1852			nlmsg_free(msg.skb);
1853			return err;
1854		}
1855	} else {
1856		int bearer_id;
1857		struct tipc_node *node;
1858		struct tipc_link *link;
1859
1860		node = tipc_node_find_by_name(net, name, &bearer_id);
1861		if (!node)
1862			return -EINVAL;
1863
1864		tipc_node_read_lock(node);
1865		link = node->links[bearer_id].link;
1866		if (!link) {
1867			tipc_node_read_unlock(node);
1868			nlmsg_free(msg.skb);
1869			return -EINVAL;
1870		}
1871
1872		err = __tipc_nl_add_link(net, &msg, link, 0);
1873		tipc_node_read_unlock(node);
1874		if (err) {
1875			nlmsg_free(msg.skb);
1876			return err;
1877		}
1878	}
1879
1880	return genlmsg_reply(msg.skb, info);
1881}
1882
1883int tipc_nl_node_reset_link_stats(struct sk_buff *skb, struct genl_info *info)
1884{
1885	int err;
1886	char *link_name;
1887	unsigned int bearer_id;
1888	struct tipc_link *link;
1889	struct tipc_node *node;
1890	struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
1891	struct net *net = sock_net(skb->sk);
1892	struct tipc_link_entry *le;
1893
1894	if (!info->attrs[TIPC_NLA_LINK])
1895		return -EINVAL;
1896
1897	err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
1898			       info->attrs[TIPC_NLA_LINK],
1899			       tipc_nl_link_policy);
1900	if (err)
1901		return err;
1902
1903	if (!attrs[TIPC_NLA_LINK_NAME])
1904		return -EINVAL;
1905
1906	link_name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
1907
1908	if (strcmp(link_name, tipc_bclink_name) == 0) {
1909		err = tipc_bclink_reset_stats(net);
1910		if (err)
1911			return err;
1912		return 0;
1913	}
1914
1915	node = tipc_node_find_by_name(net, link_name, &bearer_id);
1916	if (!node)
1917		return -EINVAL;
1918
1919	le = &node->links[bearer_id];
1920	tipc_node_read_lock(node);
1921	spin_lock_bh(&le->lock);
1922	link = node->links[bearer_id].link;
1923	if (!link) {
1924		spin_unlock_bh(&le->lock);
1925		tipc_node_read_unlock(node);
1926		return -EINVAL;
1927	}
1928	tipc_link_reset_stats(link);
1929	spin_unlock_bh(&le->lock);
1930	tipc_node_read_unlock(node);
1931	return 0;
1932}
1933
1934/* Caller should hold node lock  */
1935static int __tipc_nl_add_node_links(struct net *net, struct tipc_nl_msg *msg,
1936				    struct tipc_node *node, u32 *prev_link)
1937{
1938	u32 i;
1939	int err;
1940
1941	for (i = *prev_link; i < MAX_BEARERS; i++) {
1942		*prev_link = i;
1943
1944		if (!node->links[i].link)
1945			continue;
1946
1947		err = __tipc_nl_add_link(net, msg,
1948					 node->links[i].link, NLM_F_MULTI);
1949		if (err)
1950			return err;
1951	}
1952	*prev_link = 0;
1953
1954	return 0;
1955}
1956
1957int tipc_nl_node_dump_link(struct sk_buff *skb, struct netlink_callback *cb)
1958{
1959	struct net *net = sock_net(skb->sk);
1960	struct tipc_net *tn = net_generic(net, tipc_net_id);
1961	struct tipc_node *node;
1962	struct tipc_nl_msg msg;
1963	u32 prev_node = cb->args[0];
1964	u32 prev_link = cb->args[1];
1965	int done = cb->args[2];
1966	int err;
1967
1968	if (done)
1969		return 0;
1970
1971	msg.skb = skb;
1972	msg.portid = NETLINK_CB(cb->skb).portid;
1973	msg.seq = cb->nlh->nlmsg_seq;
1974
1975	rcu_read_lock();
1976	if (prev_node) {
1977		node = tipc_node_find(net, prev_node);
1978		if (!node) {
1979			/* We never set seq or call nl_dump_check_consistent()
1980			 * this means that setting prev_seq here will cause the
1981			 * consistence check to fail in the netlink callback
1982			 * handler. Resulting in the last NLMSG_DONE message
1983			 * having the NLM_F_DUMP_INTR flag set.
1984			 */
1985			cb->prev_seq = 1;
1986			goto out;
1987		}
1988		tipc_node_put(node);
1989
1990		list_for_each_entry_continue_rcu(node, &tn->node_list,
1991						 list) {
1992			tipc_node_read_lock(node);
1993			err = __tipc_nl_add_node_links(net, &msg, node,
1994						       &prev_link);
1995			tipc_node_read_unlock(node);
1996			if (err)
1997				goto out;
1998
1999			prev_node = node->addr;
2000		}
2001	} else {
2002		err = tipc_nl_add_bc_link(net, &msg);
2003		if (err)
2004			goto out;
2005
2006		list_for_each_entry_rcu(node, &tn->node_list, list) {
2007			tipc_node_read_lock(node);
2008			err = __tipc_nl_add_node_links(net, &msg, node,
2009						       &prev_link);
2010			tipc_node_read_unlock(node);
2011			if (err)
2012				goto out;
2013
2014			prev_node = node->addr;
2015		}
2016	}
2017	done = 1;
2018out:
2019	rcu_read_unlock();
2020
2021	cb->args[0] = prev_node;
2022	cb->args[1] = prev_link;
2023	cb->args[2] = done;
2024
2025	return skb->len;
2026}
2027
2028int tipc_nl_node_set_monitor(struct sk_buff *skb, struct genl_info *info)
2029{
2030	struct nlattr *attrs[TIPC_NLA_MON_MAX + 1];
2031	struct net *net = sock_net(skb->sk);
2032	int err;
2033
2034	if (!info->attrs[TIPC_NLA_MON])
2035		return -EINVAL;
2036
2037	err = nla_parse_nested(attrs, TIPC_NLA_MON_MAX,
2038			       info->attrs[TIPC_NLA_MON],
2039			       tipc_nl_monitor_policy);
2040	if (err)
2041		return err;
2042
2043	if (attrs[TIPC_NLA_MON_ACTIVATION_THRESHOLD]) {
2044		u32 val;
2045
2046		val = nla_get_u32(attrs[TIPC_NLA_MON_ACTIVATION_THRESHOLD]);
2047		err = tipc_nl_monitor_set_threshold(net, val);
2048		if (err)
2049			return err;
2050	}
2051
2052	return 0;
2053}
2054
2055static int __tipc_nl_add_monitor_prop(struct net *net, struct tipc_nl_msg *msg)
2056{
2057	struct nlattr *attrs;
2058	void *hdr;
2059	u32 val;
2060
2061	hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
2062			  0, TIPC_NL_MON_GET);
2063	if (!hdr)
2064		return -EMSGSIZE;
2065
2066	attrs = nla_nest_start(msg->skb, TIPC_NLA_MON);
2067	if (!attrs)
2068		goto msg_full;
2069
2070	val = tipc_nl_monitor_get_threshold(net);
2071
2072	if (nla_put_u32(msg->skb, TIPC_NLA_MON_ACTIVATION_THRESHOLD, val))
2073		goto attr_msg_full;
2074
2075	nla_nest_end(msg->skb, attrs);
2076	genlmsg_end(msg->skb, hdr);
2077
2078	return 0;
2079
2080attr_msg_full:
2081	nla_nest_cancel(msg->skb, attrs);
2082msg_full:
2083	genlmsg_cancel(msg->skb, hdr);
2084
2085	return -EMSGSIZE;
2086}
2087
2088int tipc_nl_node_get_monitor(struct sk_buff *skb, struct genl_info *info)
2089{
2090	struct net *net = sock_net(skb->sk);
2091	struct tipc_nl_msg msg;
2092	int err;
2093
2094	msg.skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
2095	msg.portid = info->snd_portid;
2096	msg.seq = info->snd_seq;
2097
2098	err = __tipc_nl_add_monitor_prop(net, &msg);
2099	if (err) {
2100		nlmsg_free(msg.skb);
2101		return err;
2102	}
2103
2104	return genlmsg_reply(msg.skb, info);
2105}
2106
2107int tipc_nl_node_dump_monitor(struct sk_buff *skb, struct netlink_callback *cb)
2108{
2109	struct net *net = sock_net(skb->sk);
2110	u32 prev_bearer = cb->args[0];
2111	struct tipc_nl_msg msg;
2112	int err;
2113	int i;
2114
2115	if (prev_bearer == MAX_BEARERS)
2116		return 0;
2117
2118	msg.skb = skb;
2119	msg.portid = NETLINK_CB(cb->skb).portid;
2120	msg.seq = cb->nlh->nlmsg_seq;
2121
2122	rtnl_lock();
2123	for (i = prev_bearer; i < MAX_BEARERS; i++) {
2124		prev_bearer = i;
2125		err = __tipc_nl_add_monitor(net, &msg, prev_bearer);
2126		if (err)
2127			goto out;
2128	}
2129
2130out:
2131	rtnl_unlock();
2132	cb->args[0] = prev_bearer;
2133
2134	return skb->len;
2135}
2136
2137int tipc_nl_node_dump_monitor_peer(struct sk_buff *skb,
2138				   struct netlink_callback *cb)
2139{
2140	struct net *net = sock_net(skb->sk);
2141	u32 prev_node = cb->args[1];
2142	u32 bearer_id = cb->args[2];
2143	int done = cb->args[0];
2144	struct tipc_nl_msg msg;
2145	int err;
2146
2147	if (!prev_node) {
2148		struct nlattr **attrs;
2149		struct nlattr *mon[TIPC_NLA_MON_MAX + 1];
2150
2151		err = tipc_nlmsg_parse(cb->nlh, &attrs);
2152		if (err)
2153			return err;
2154
2155		if (!attrs[TIPC_NLA_MON])
2156			return -EINVAL;
2157
2158		err = nla_parse_nested(mon, TIPC_NLA_MON_MAX,
2159				       attrs[TIPC_NLA_MON],
2160				       tipc_nl_monitor_policy);
2161		if (err)
2162			return err;
2163
2164		if (!mon[TIPC_NLA_MON_REF])
2165			return -EINVAL;
2166
2167		bearer_id = nla_get_u32(mon[TIPC_NLA_MON_REF]);
2168
2169		if (bearer_id >= MAX_BEARERS)
2170			return -EINVAL;
2171	}
2172
2173	if (done)
2174		return 0;
2175
2176	msg.skb = skb;
2177	msg.portid = NETLINK_CB(cb->skb).portid;
2178	msg.seq = cb->nlh->nlmsg_seq;
2179
2180	rtnl_lock();
2181	err = tipc_nl_add_monitor_peer(net, &msg, bearer_id, &prev_node);
2182	if (!err)
2183		done = 1;
2184
2185	rtnl_unlock();
2186	cb->args[0] = done;
2187	cb->args[1] = prev_node;
2188	cb->args[2] = bearer_id;
2189
2190	return skb->len;
2191}