net/tipc/node.c

   1 /*
   2  * net/tipc/node.c: TIPC node management routines
   3  *
   4  * Copyright (c) 2000-2006, 2012-2015, Ericsson AB
   5  * Copyright (c) 2005-2006, 2010-2014, Wind River Systems
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. Neither the names of the copyright holders nor the names of its
  17  *    contributors may be used to endorse or promote products derived from
  18  *    this software without specific prior written permission.
  19  *
  20  * Alternatively, this software may be distributed under the terms of the
  21  * GNU General Public License ("GPL") version 2 as published by the Free
  22  * Software Foundation.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  25  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  28  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  29  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  30  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  31  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  32  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  33  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  34  * POSSIBILITY OF SUCH DAMAGE.
  35  */
  36
  37 #include "core.h"
  38 #include "link.h"
  39 #include "node.h"
  40 #include "name_distr.h"
  41 #include "socket.h"
  42 #include "bcast.h"
  43
  44 static void node_lost_contact(struct tipc_node *n_ptr);
  45 static void node_established_contact(struct tipc_node *n_ptr);
  46 static void tipc_node_delete(struct tipc_node *node);
  47
  48 struct tipc_sock_conn {
  49         u32 port;
  50         u32 peer_port;
  51         u32 peer_node;
  52         struct list_head list;
  53 };
  54
  55 static const struct nla_policy tipc_nl_node_policy[TIPC_NLA_NODE_MAX + 1] = {
  56         [TIPC_NLA_NODE_UNSPEC]          = { .type = NLA_UNSPEC },
  57         [TIPC_NLA_NODE_ADDR]            = { .type = NLA_U32 },
  58         [TIPC_NLA_NODE_UP]              = { .type = NLA_FLAG }
  59 };
  60
  61 /*
  62  * A trivial power-of-two bitmask technique is used for speed, since this
  63  * operation is done for every incoming TIPC packet. The number of hash table
  64  * entries has been chosen so that no hash chain exceeds 8 nodes and will
  65  * usually be much smaller (typically only a single node).
  66  */
  67 static unsigned int tipc_hashfn(u32 addr)
  68 {
  69         return addr & (NODE_HTABLE_SIZE - 1);
  70 }
  71
  72 static void tipc_node_kref_release(struct kref *kref)
  73 {
  74         struct tipc_node *node = container_of(kref, struct tipc_node, kref);
  75
  76         tipc_node_delete(node);
  77 }
  78
  79 void tipc_node_put(struct tipc_node *node)
  80 {
  81         kref_put(&node->kref, tipc_node_kref_release);
  82 }
  83
  84 static void tipc_node_get(struct tipc_node *node)
  85 {
  86         kref_get(&node->kref);
  87 }
  88
  89 /*
  90  * tipc_node_find - locate specified node object, if it exists
  91  */
  92 struct tipc_node *tipc_node_find(struct net *net, u32 addr)
  93 {
  94         struct tipc_net *tn = net_generic(net, tipc_net_id);
  95         struct tipc_node *node;
  96
  97         if (unlikely(!in_own_cluster_exact(net, addr)))
  98                 return NULL;
  99
 100         rcu_read_lock();
 101         hlist_for_each_entry_rcu(node, &tn->node_htable[tipc_hashfn(addr)],
 102                                  hash) {
 103                 if (node->addr == addr) {
 104                         tipc_node_get(node);
 105                         rcu_read_unlock();
 106                         return node;
 107                 }
 108         }
 109         rcu_read_unlock();
 110         return NULL;
 111 }
 112
 113 struct tipc_node *tipc_node_create(struct net *net, u32 addr)
 114 {
 115         struct tipc_net *tn = net_generic(net, tipc_net_id);
 116         struct tipc_node *n_ptr, *temp_node;
 117
 118         spin_lock_bh(&tn->node_list_lock);
 119         n_ptr = tipc_node_find(net, addr);
 120         if (n_ptr)
 121                 goto exit;
 122         n_ptr = kzalloc(sizeof(*n_ptr), GFP_ATOMIC);
 123         if (!n_ptr) {
 124                 pr_warn("Node creation failed, no memory\n");
 125                 goto exit;
 126         }
 127         n_ptr->addr = addr;
 128         n_ptr->net = net;
 129         kref_init(&n_ptr->kref);
 130         spin_lock_init(&n_ptr->lock);
 131         INIT_HLIST_NODE(&n_ptr->hash);
 132         INIT_LIST_HEAD(&n_ptr->list);
 133         INIT_LIST_HEAD(&n_ptr->publ_list);
 134         INIT_LIST_HEAD(&n_ptr->conn_sks);
 135         __skb_queue_head_init(&n_ptr->bclink.deferdq);
 136         hlist_add_head_rcu(&n_ptr->hash, &tn->node_htable[tipc_hashfn(addr)]);
 137         list_for_each_entry_rcu(temp_node, &tn->node_list, list) {
 138                 if (n_ptr->addr < temp_node->addr)
 139                         break;
 140         }
 141         list_add_tail_rcu(&n_ptr->list, &temp_node->list);
 142         n_ptr->action_flags = TIPC_WAIT_PEER_LINKS_DOWN;
 143         n_ptr->signature = INVALID_NODE_SIG;
 144         tipc_node_get(n_ptr);
 145 exit:
 146         spin_unlock_bh(&tn->node_list_lock);
 147         return n_ptr;
 148 }
 149
 150 static void tipc_node_delete(struct tipc_node *node)
 151 {
 152         list_del_rcu(&node->list);
 153         hlist_del_rcu(&node->hash);
 154         kfree_rcu(node, rcu);
 155 }
 156
 157 void tipc_node_stop(struct net *net)
 158 {
 159         struct tipc_net *tn = net_generic(net, tipc_net_id);
 160         struct tipc_node *node, *t_node;
 161
 162         spin_lock_bh(&tn->node_list_lock);
 163         list_for_each_entry_safe(node, t_node, &tn->node_list, list)
 164                 tipc_node_put(node);
 165         spin_unlock_bh(&tn->node_list_lock);
 166 }
 167
 168 int tipc_node_add_conn(struct net *net, u32 dnode, u32 port, u32 peer_port)
 169 {
 170         struct tipc_node *node;
 171         struct tipc_sock_conn *conn;
 172         int err = 0;
 173
 174         if (in_own_node(net, dnode))
 175                 return 0;
 176
 177         node = tipc_node_find(net, dnode);
 178         if (!node) {
 179                 pr_warn("Connecting sock to node 0x%x failed\n", dnode);
 180                 return -EHOSTUNREACH;
 181         }
 182         conn = kmalloc(sizeof(*conn), GFP_ATOMIC);
 183         if (!conn) {
 184                 err = -EHOSTUNREACH;
 185                 goto exit;
 186         }
 187         conn->peer_node = dnode;
 188         conn->port = port;
 189         conn->peer_port = peer_port;
 190
 191         tipc_node_lock(node);
 192         list_add_tail(&conn->list, &node->conn_sks);
 193         tipc_node_unlock(node);
 194 exit:
 195         tipc_node_put(node);
 196         return err;
 197 }
 198
 199 void tipc_node_remove_conn(struct net *net, u32 dnode, u32 port)
 200 {
 201         struct tipc_node *node;
 202         struct tipc_sock_conn *conn, *safe;
 203
 204         if (in_own_node(net, dnode))
 205                 return;
 206
 207         node = tipc_node_find(net, dnode);
 208         if (!node)
 209                 return;
 210
 211         tipc_node_lock(node);
 212         list_for_each_entry_safe(conn, safe, &node->conn_sks, list) {
 213                 if (port != conn->port)
 214                         continue;
 215                 list_del(&conn->list);
 216                 kfree(conn);
 217         }
 218         tipc_node_unlock(node);
 219         tipc_node_put(node);
 220 }
 221
 222 /**
 223  * tipc_node_link_up - handle addition of link
 224  *
 225  * Link becomes active (alone or shared) or standby, depending on its priority.
 226  */
 227 void tipc_node_link_up(struct tipc_node *n_ptr, struct tipc_link *l_ptr)
 228 {
 229         struct tipc_link **active = &n_ptr->active_links[0];
 230
 231         n_ptr->working_links++;
 232         n_ptr->action_flags |= TIPC_NOTIFY_LINK_UP;
 233         n_ptr->link_id = l_ptr->peer_bearer_id << 16 | l_ptr->bearer_id;
 234
 235         pr_debug("Established link <%s> on network plane %c\n",
 236                  l_ptr->name, l_ptr->net_plane);
 237
 238         if (!active[0]) {
 239                 active[0] = active[1] = l_ptr;
 240                 node_established_contact(n_ptr);
 241                 goto exit;
 242         }
 243         if (l_ptr->priority < active[0]->priority) {
 244                 pr_debug("New link <%s> becomes standby\n", l_ptr->name);
 245                 goto exit;
 246         }
 247         tipc_link_dup_queue_xmit(active[0], l_ptr);
 248         if (l_ptr->priority == active[0]->priority) {
 249                 active[0] = l_ptr;
 250                 goto exit;
 251         }
 252         pr_debug("Old link <%s> becomes standby\n", active[0]->name);
 253         if (active[1] != active[0])
 254                 pr_debug("Old link <%s> becomes standby\n", active[1]->name);
 255         active[0] = active[1] = l_ptr;
 256 exit:
 257         /* Leave room for changeover header when returning 'mtu' to users: */
 258         n_ptr->act_mtus[0] = active[0]->mtu - INT_H_SIZE;
 259         n_ptr->act_mtus[1] = active[1]->mtu - INT_H_SIZE;
 260 }
 261
 262 /**
 263  * node_select_active_links - select active link
 264  */
 265 static void node_select_active_links(struct tipc_node *n_ptr)
 266 {
 267         struct tipc_link **active = &n_ptr->active_links[0];
 268         u32 i;
 269         u32 highest_prio = 0;
 270
 271         active[0] = active[1] = NULL;
 272
 273         for (i = 0; i < MAX_BEARERS; i++) {
 274                 struct tipc_link *l_ptr = n_ptr->links[i];
 275
 276                 if (!l_ptr || !tipc_link_is_up(l_ptr) ||
 277                     (l_ptr->priority < highest_prio))
 278                         continue;
 279
 280                 if (l_ptr->priority > highest_prio) {
 281                         highest_prio = l_ptr->priority;
 282                         active[0] = active[1] = l_ptr;
 283                 } else {
 284                         active[1] = l_ptr;
 285                 }
 286         }
 287 }
 288
 289 /**
 290  * tipc_node_link_down - handle loss of link
 291  */
 292 void tipc_node_link_down(struct tipc_node *n_ptr, struct tipc_link *l_ptr)
 293 {
 294         struct tipc_net *tn = net_generic(n_ptr->net, tipc_net_id);
 295         struct tipc_link **active;
 296
 297         n_ptr->working_links--;
 298         n_ptr->action_flags |= TIPC_NOTIFY_LINK_DOWN;
 299         n_ptr->link_id = l_ptr->peer_bearer_id << 16 | l_ptr->bearer_id;
 300
 301         if (!tipc_link_is_active(l_ptr)) {
 302                 pr_debug("Lost standby link <%s> on network plane %c\n",
 303                          l_ptr->name, l_ptr->net_plane);
 304                 return;
 305         }
 306         pr_debug("Lost link <%s> on network plane %c\n",
 307                  l_ptr->name, l_ptr->net_plane);
 308
 309         active = &n_ptr->active_links[0];
 310         if (active[0] == l_ptr)
 311                 active[0] = active[1];
 312         if (active[1] == l_ptr)
 313                 active[1] = active[0];
 314         if (active[0] == l_ptr)
 315                 node_select_active_links(n_ptr);
 316         if (tipc_node_is_up(n_ptr))
 317                 tipc_link_failover_send_queue(l_ptr);
 318         else
 319                 node_lost_contact(n_ptr);
 320
 321         /* Leave room for changeover header when returning 'mtu' to users: */
 322         if (active[0]) {
 323                 n_ptr->act_mtus[0] = active[0]->mtu - INT_H_SIZE;
 324                 n_ptr->act_mtus[1] = active[1]->mtu - INT_H_SIZE;
 325                 return;
 326         }
 327         /* Loopback link went down? No fragmentation needed from now on. */
 328         if (n_ptr->addr == tn->own_addr) {
 329                 n_ptr->act_mtus[0] = MAX_MSG_SIZE;
 330                 n_ptr->act_mtus[1] = MAX_MSG_SIZE;
 331         }
 332 }
 333
 334 int tipc_node_active_links(struct tipc_node *n_ptr)
 335 {
 336         return n_ptr->active_links[0] != NULL;
 337 }
 338
 339 int tipc_node_is_up(struct tipc_node *n_ptr)
 340 {
 341         return tipc_node_active_links(n_ptr);
 342 }
 343
 344 void tipc_node_attach_link(struct tipc_node *n_ptr, struct tipc_link *l_ptr)
 345 {
 346         n_ptr->links[l_ptr->bearer_id] = l_ptr;
 347         n_ptr->link_cnt++;
 348 }
 349
 350 void tipc_node_detach_link(struct tipc_node *n_ptr, struct tipc_link *l_ptr)
 351 {
 352         int i;
 353
 354         for (i = 0; i < MAX_BEARERS; i++) {
 355                 if (l_ptr != n_ptr->links[i])
 356                         continue;
 357                 n_ptr->links[i] = NULL;
 358                 n_ptr->link_cnt--;
 359         }
 360 }
 361
 362 static void node_established_contact(struct tipc_node *n_ptr)
 363 {
 364         n_ptr->action_flags |= TIPC_NOTIFY_NODE_UP;
 365         n_ptr->bclink.oos_state = 0;
 366         n_ptr->bclink.acked = tipc_bclink_get_last_sent(n_ptr->net);
 367         tipc_bclink_add_node(n_ptr->net, n_ptr->addr);
 368 }
 369
 370 static void node_lost_contact(struct tipc_node *n_ptr)
 371 {
 372         char addr_string[16];
 373         struct tipc_sock_conn *conn, *safe;
 374         struct list_head *conns = &n_ptr->conn_sks;
 375         struct sk_buff *skb;
 376         struct tipc_net *tn = net_generic(n_ptr->net, tipc_net_id);
 377         uint i;
 378
 379         pr_debug("Lost contact with %s\n",
 380                  tipc_addr_string_fill(addr_string, n_ptr->addr));
 381
 382         /* Flush broadcast link info associated with lost node */
 383         if (n_ptr->bclink.recv_permitted) {
 384                 __skb_queue_purge(&n_ptr->bclink.deferdq);
 385
 386                 if (n_ptr->bclink.reasm_buf) {
 387                         kfree_skb(n_ptr->bclink.reasm_buf);
 388                         n_ptr->bclink.reasm_buf = NULL;
 389                 }
 390
 391                 tipc_bclink_remove_node(n_ptr->net, n_ptr->addr);
 392                 tipc_bclink_acknowledge(n_ptr, INVALID_LINK_SEQ);
 393
 394                 n_ptr->bclink.recv_permitted = false;
 395         }
 396
 397         /* Abort any ongoing link failover */
 398         for (i = 0; i < MAX_BEARERS; i++) {
 399                 struct tipc_link *l_ptr = n_ptr->links[i];
 400                 if (!l_ptr)
 401                         continue;
 402                 l_ptr->flags &= ~LINK_FAILINGOVER;
 403                 l_ptr->failover_checkpt = 0;
 404                 l_ptr->failover_pkts = 0;
 405                 kfree_skb(l_ptr->failover_skb);
 406                 l_ptr->failover_skb = NULL;
 407                 tipc_link_reset_fragments(l_ptr);
 408         }
 409
 410         n_ptr->action_flags &= ~TIPC_WAIT_OWN_LINKS_DOWN;
 411
 412         /* Prevent re-contact with node until cleanup is done */
 413         n_ptr->action_flags |= TIPC_WAIT_PEER_LINKS_DOWN;
 414
 415         /* Notify publications from this node */
 416         n_ptr->action_flags |= TIPC_NOTIFY_NODE_DOWN;
 417
 418         /* Notify sockets connected to node */
 419         list_for_each_entry_safe(conn, safe, conns, list) {
 420                 skb = tipc_msg_create(TIPC_CRITICAL_IMPORTANCE, TIPC_CONN_MSG,
 421                                       SHORT_H_SIZE, 0, tn->own_addr,
 422                                       conn->peer_node, conn->port,
 423                                       conn->peer_port, TIPC_ERR_NO_NODE);
 424                 if (likely(skb)) {
 425                         skb_queue_tail(n_ptr->inputq, skb);
 426                         n_ptr->action_flags |= TIPC_MSG_EVT;
 427                 }
 428                 list_del(&conn->list);
 429                 kfree(conn);
 430         }
 431 }
 432
 433 /**
 434  * tipc_node_get_linkname - get the name of a link
 435  *
 436  * @bearer_id: id of the bearer
 437  * @node: peer node address
 438  * @linkname: link name output buffer
 439  *
 440  * Returns 0 on success
 441  */
 442 int tipc_node_get_linkname(struct net *net, u32 bearer_id, u32 addr,
 443                            char *linkname, size_t len)
 444 {
 445         struct tipc_link *link;
 446         int err = -EINVAL;
 447         struct tipc_node *node = tipc_node_find(net, addr);
 448
 449         if (!node)
 450                 return err;
 451
 452         if (bearer_id >= MAX_BEARERS)
 453                 goto exit;
 454
 455         tipc_node_lock(node);
 456         link = node->links[bearer_id];
 457         if (link) {
 458                 strncpy(linkname, link->name, len);
 459                 err = 0;
 460         }
 461 exit:
 462         tipc_node_unlock(node);
 463         tipc_node_put(node);
 464         return err;
 465 }
 466
 467 void tipc_node_unlock(struct tipc_node *node)
 468 {
 469         struct net *net = node->net;
 470         u32 addr = 0;
 471         u32 flags = node->action_flags;
 472         u32 link_id = 0;
 473         struct list_head *publ_list;
 474         struct sk_buff_head *inputq = node->inputq;
 475         struct sk_buff_head *namedq;
 476
 477         if (likely(!flags || (flags == TIPC_MSG_EVT))) {
 478                 node->action_flags = 0;
 479                 spin_unlock_bh(&node->lock);
 480                 if (flags == TIPC_MSG_EVT)
 481                         tipc_sk_rcv(net, inputq);
 482                 return;
 483         }
 484
 485         addr = node->addr;
 486         link_id = node->link_id;
 487         namedq = node->namedq;
 488         publ_list = &node->publ_list;
 489
 490         node->action_flags &= ~(TIPC_MSG_EVT |
 491                                 TIPC_NOTIFY_NODE_DOWN | TIPC_NOTIFY_NODE_UP |
 492                                 TIPC_NOTIFY_LINK_DOWN | TIPC_NOTIFY_LINK_UP |
 493                                 TIPC_WAKEUP_BCAST_USERS | TIPC_BCAST_MSG_EVT |
 494                                 TIPC_NAMED_MSG_EVT | TIPC_BCAST_RESET);
 495
 496         spin_unlock_bh(&node->lock);
 497
 498         if (flags & TIPC_NOTIFY_NODE_DOWN)
 499                 tipc_publ_notify(net, publ_list, addr);
 500
 501         if (flags & TIPC_WAKEUP_BCAST_USERS)
 502                 tipc_bclink_wakeup_users(net);
 503
 504         if (flags & TIPC_NOTIFY_NODE_UP)
 505                 tipc_named_node_up(net, addr);
 506
 507         if (flags & TIPC_NOTIFY_LINK_UP)
 508                 tipc_nametbl_publish(net, TIPC_LINK_STATE, addr, addr,
 509                                      TIPC_NODE_SCOPE, link_id, addr);
 510
 511         if (flags & TIPC_NOTIFY_LINK_DOWN)
 512                 tipc_nametbl_withdraw(net, TIPC_LINK_STATE, addr,
 513                                       link_id, addr);
 514
 515         if (flags & TIPC_MSG_EVT)
 516                 tipc_sk_rcv(net, inputq);
 517
 518         if (flags & TIPC_NAMED_MSG_EVT)
 519                 tipc_named_rcv(net, namedq);
 520
 521         if (flags & TIPC_BCAST_MSG_EVT)
 522                 tipc_bclink_input(net);
 523
 524         if (flags & TIPC_BCAST_RESET)
 525                 tipc_link_reset_all(node);
 526 }
 527
 528 /* Caller should hold node lock for the passed node */
 529 static int __tipc_nl_add_node(struct tipc_nl_msg *msg, struct tipc_node *node)
 530 {
 531         void *hdr;
 532         struct nlattr *attrs;
 533
 534         hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
 535                           NLM_F_MULTI, TIPC_NL_NODE_GET);
 536         if (!hdr)
 537                 return -EMSGSIZE;
 538
 539         attrs = nla_nest_start(msg->skb, TIPC_NLA_NODE);
 540         if (!attrs)
 541                 goto msg_full;
 542
 543         if (nla_put_u32(msg->skb, TIPC_NLA_NODE_ADDR, node->addr))
 544                 goto attr_msg_full;
 545         if (tipc_node_is_up(node))
 546                 if (nla_put_flag(msg->skb, TIPC_NLA_NODE_UP))
 547                         goto attr_msg_full;
 548
 549         nla_nest_end(msg->skb, attrs);
 550         genlmsg_end(msg->skb, hdr);
 551
 552         return 0;
 553
 554 attr_msg_full:
 555         nla_nest_cancel(msg->skb, attrs);
 556 msg_full:
 557         genlmsg_cancel(msg->skb, hdr);
 558
 559         return -EMSGSIZE;
 560 }
 561
 562 int tipc_nl_node_dump(struct sk_buff *skb, struct netlink_callback *cb)
 563 {
 564         int err;
 565         struct net *net = sock_net(skb->sk);
 566         struct tipc_net *tn = net_generic(net, tipc_net_id);
 567         int done = cb->args[0];
 568         int last_addr = cb->args[1];
 569         struct tipc_node *node;
 570         struct tipc_nl_msg msg;
 571
 572         if (done)
 573                 return 0;
 574
 575         msg.skb = skb;
 576         msg.portid = NETLINK_CB(cb->skb).portid;
 577         msg.seq = cb->nlh->nlmsg_seq;
 578
 579         rcu_read_lock();
 580         if (last_addr) {
 581                 node = tipc_node_find(net, last_addr);
 582                 if (!node) {
 583                         rcu_read_unlock();
 584                         /* We never set seq or call nl_dump_check_consistent()
 585                          * this means that setting prev_seq here will cause the
 586                          * consistence check to fail in the netlink callback
 587                          * handler. Resulting in the NLMSG_DONE message having
 588                          * the NLM_F_DUMP_INTR flag set if the node state
 589                          * changed while we released the lock.
 590                          */
 591                         cb->prev_seq = 1;
 592                         return -EPIPE;
 593                 }
 594                 tipc_node_put(node);
 595         }
 596
 597         list_for_each_entry_rcu(node, &tn->node_list, list) {
 598                 if (last_addr) {
 599                         if (node->addr == last_addr)
 600                                 last_addr = 0;
 601                         else
 602                                 continue;
 603                 }
 604
 605                 tipc_node_lock(node);
 606                 err = __tipc_nl_add_node(&msg, node);
 607                 if (err) {
 608                         last_addr = node->addr;
 609                         tipc_node_unlock(node);
 610                         goto out;
 611                 }
 612
 613                 tipc_node_unlock(node);
 614         }
 615         done = 1;
 616 out:
 617         cb->args[0] = done;
 618         cb->args[1] = last_addr;
 619         rcu_read_unlock();
 620
 621         return skb->len;
 622 }