net/tipc/node.c

   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
  44 static void node_lost_contact(struct tipc_node *n_ptr);
  45 static void node_established_contact(struct tipc_node *n_ptr);
  46
  47 static DEFINE_SPINLOCK(node_create_lock);
  48
  49 static struct hlist_head node_htable[NODE_HTABLE_SIZE];
  50 LIST_HEAD(tipc_node_list);
  51 static u32 tipc_num_nodes;
  52
  53 static 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  */
  61 static inline 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  */
  69
  70 struct tipc_node *tipc_node_find(u32 addr)
  71 {
  72         struct tipc_node *node;
  73         struct hlist_node *pos;
  74
  75         if (unlikely(!in_own_cluster(addr)))
  76                 return NULL;
  77
  78         hlist_for_each_entry(node, pos, &node_htable[tipc_hashfn(addr)], hash) {
  79                 if (node->addr == addr)
  80                         return node;
  81         }
  82         return NULL;
  83 }
  84
  85 /**
  86  * tipc_node_create - create neighboring node
  87  *
  88  * Currently, this routine is called by neighbor discovery code, which holds
  89  * net_lock for reading only.  We must take node_create_lock to ensure a node
  90  * isn't created twice if two different bearers discover the node at the same
  91  * time.  (It would be preferable to switch to holding net_lock in write mode,
  92  * but this is a non-trivial change.)
  93  */
  94
  95 struct tipc_node *tipc_node_create(u32 addr)
  96 {
  97         struct tipc_node *n_ptr, *temp_node;
  98
  99         spin_lock_bh(&node_create_lock);
 100
 101         n_ptr = tipc_node_find(addr);
 102         if (n_ptr) {
 103                 spin_unlock_bh(&node_create_lock);
 104                 return n_ptr;
 105         }
 106
 107         n_ptr = kzalloc(sizeof(*n_ptr), GFP_ATOMIC);
 108         if (!n_ptr) {
 109                 spin_unlock_bh(&node_create_lock);
 110                 warn("Node creation failed, no memory\n");
 111                 return NULL;
 112         }
 113
 114         n_ptr->addr = addr;
 115         spin_lock_init(&n_ptr->lock);
 116         INIT_HLIST_NODE(&n_ptr->hash);
 117         INIT_LIST_HEAD(&n_ptr->list);
 118         INIT_LIST_HEAD(&n_ptr->nsub);
 119
 120         hlist_add_head(&n_ptr->hash, &node_htable[tipc_hashfn(addr)]);
 121
 122         list_for_each_entry(temp_node, &tipc_node_list, list) {
 123                 if (n_ptr->addr < temp_node->addr)
 124                         break;
 125         }
 126         list_add_tail(&n_ptr->list, &temp_node->list);
 127         n_ptr->block_setup = WAIT_PEER_DOWN;
 128         n_ptr->signature = INVALID_NODE_SIG;
 129
 130         tipc_num_nodes++;
 131
 132         spin_unlock_bh(&node_create_lock);
 133         return n_ptr;
 134 }
 135
 136 void tipc_node_delete(struct tipc_node *n_ptr)
 137 {
 138         list_del(&n_ptr->list);
 139         hlist_del(&n_ptr->hash);
 140         kfree(n_ptr);
 141
 142         tipc_num_nodes--;
 143 }
 144
 145
 146 /**
 147  * tipc_node_link_up - handle addition of link
 148  *
 149  * Link becomes active (alone or shared) or standby, depending on its priority.
 150  */
 151
 152 void tipc_node_link_up(struct tipc_node *n_ptr, struct tipc_link *l_ptr)
 153 {
 154         struct tipc_link **active = &n_ptr->active_links[0];
 155
 156         n_ptr->working_links++;
 157
 158         info("Established link <%s> on network plane %c\n",
 159              l_ptr->name, l_ptr->b_ptr->net_plane);
 160
 161         if (!active[0]) {
 162                 active[0] = active[1] = l_ptr;
 163                 node_established_contact(n_ptr);
 164                 return;
 165         }
 166         if (l_ptr->priority < active[0]->priority) {
 167                 info("New link <%s> becomes standby\n", l_ptr->name);
 168                 return;
 169         }
 170         tipc_link_send_duplicate(active[0], l_ptr);
 171         if (l_ptr->priority == active[0]->priority) {
 172                 active[0] = l_ptr;
 173                 return;
 174         }
 175         info("Old link <%s> becomes standby\n", active[0]->name);
 176         if (active[1] != active[0])
 177                 info("Old link <%s> becomes standby\n", active[1]->name);
 178         active[0] = active[1] = l_ptr;
 179 }
 180
 181 /**
 182  * node_select_active_links - select active link
 183  */
 184
 185 static void node_select_active_links(struct tipc_node *n_ptr)
 186 {
 187         struct tipc_link **active = &n_ptr->active_links[0];
 188         u32 i;
 189         u32 highest_prio = 0;
 190
 191         active[0] = active[1] = NULL;
 192
 193         for (i = 0; i < MAX_BEARERS; i++) {
 194                 struct tipc_link *l_ptr = n_ptr->links[i];
 195
 196                 if (!l_ptr || !tipc_link_is_up(l_ptr) ||
 197                     (l_ptr->priority < highest_prio))
 198                         continue;
 199
 200                 if (l_ptr->priority > highest_prio) {
 201                         highest_prio = l_ptr->priority;
 202                         active[0] = active[1] = l_ptr;
 203                 } else {
 204                         active[1] = l_ptr;
 205                 }
 206         }
 207 }
 208
 209 /**
 210  * tipc_node_link_down - handle loss of link
 211  */
 212
 213 void tipc_node_link_down(struct tipc_node *n_ptr, struct tipc_link *l_ptr)
 214 {
 215         struct tipc_link **active;
 216
 217         n_ptr->working_links--;
 218
 219         if (!tipc_link_is_active(l_ptr)) {
 220                 info("Lost standby link <%s> on network plane %c\n",
 221                      l_ptr->name, l_ptr->b_ptr->net_plane);
 222                 return;
 223         }
 224         info("Lost link <%s> on network plane %c\n",
 225                 l_ptr->name, l_ptr->b_ptr->net_plane);
 226
 227         active = &n_ptr->active_links[0];
 228         if (active[0] == l_ptr)
 229                 active[0] = active[1];
 230         if (active[1] == l_ptr)
 231                 active[1] = active[0];
 232         if (active[0] == l_ptr)
 233                 node_select_active_links(n_ptr);
 234         if (tipc_node_is_up(n_ptr))
 235                 tipc_link_changeover(l_ptr);
 236         else
 237                 node_lost_contact(n_ptr);
 238 }
 239
 240 int tipc_node_active_links(struct tipc_node *n_ptr)
 241 {
 242         return n_ptr->active_links[0] != NULL;
 243 }
 244
 245 int tipc_node_redundant_links(struct tipc_node *n_ptr)
 246 {
 247         return n_ptr->working_links > 1;
 248 }
 249
 250 int tipc_node_is_up(struct tipc_node *n_ptr)
 251 {
 252         return tipc_node_active_links(n_ptr);
 253 }
 254
 255 void tipc_node_attach_link(struct tipc_node *n_ptr, struct tipc_link *l_ptr)
 256 {
 257         n_ptr->links[l_ptr->b_ptr->identity] = l_ptr;
 258         atomic_inc(&tipc_num_links);
 259         n_ptr->link_cnt++;
 260 }
 261
 262 void tipc_node_detach_link(struct tipc_node *n_ptr, struct tipc_link *l_ptr)
 263 {
 264         n_ptr->links[l_ptr->b_ptr->identity] = NULL;
 265         atomic_dec(&tipc_num_links);
 266         n_ptr->link_cnt--;
 267 }
 268
 269 static void node_established_contact(struct tipc_node *n_ptr)
 270 {
 271         tipc_k_signal((Handler)tipc_named_node_up, n_ptr->addr);
 272
 273         if (n_ptr->bclink.supportable) {
 274                 n_ptr->bclink.acked = tipc_bclink_get_last_sent();
 275                 tipc_bclink_add_node(n_ptr->addr);
 276                 n_ptr->bclink.supported = 1;
 277         }
 278 }
 279
 280 static void node_name_purge_complete(unsigned long node_addr)
 281 {
 282         struct tipc_node *n_ptr;
 283
 284         read_lock_bh(&tipc_net_lock);
 285         n_ptr = tipc_node_find(node_addr);
 286         if (n_ptr) {
 287                 tipc_node_lock(n_ptr);
 288                 n_ptr->block_setup &= ~WAIT_NAMES_GONE;
 289                 tipc_node_unlock(n_ptr);
 290         }
 291         read_unlock_bh(&tipc_net_lock);
 292 }
 293
 294 static void node_lost_contact(struct tipc_node *n_ptr)
 295 {
 296         char addr_string[16];
 297         u32 i;
 298
 299         info("Lost contact with %s\n",
 300              tipc_addr_string_fill(addr_string, n_ptr->addr));
 301
 302         /* Flush broadcast link info associated with lost node */
 303
 304         if (n_ptr->bclink.supported) {
 305                 while (n_ptr->bclink.deferred_head) {
 306                         struct sk_buff *buf = n_ptr->bclink.deferred_head;
 307                         n_ptr->bclink.deferred_head = buf->next;
 308                         kfree_skb(buf);
 309                 }
 310                 n_ptr->bclink.deferred_size = 0;
 311
 312                 if (n_ptr->bclink.defragm) {
 313                         kfree_skb(n_ptr->bclink.defragm);
 314                         n_ptr->bclink.defragm = NULL;
 315                 }
 316
 317                 tipc_bclink_remove_node(n_ptr->addr);
 318                 tipc_bclink_acknowledge(n_ptr, INVALID_LINK_SEQ);
 319
 320                 n_ptr->bclink.supported = 0;
 321         }
 322
 323         /* Abort link changeover */
 324         for (i = 0; i < MAX_BEARERS; i++) {
 325                 struct tipc_link *l_ptr = n_ptr->links[i];
 326                 if (!l_ptr)
 327                         continue;
 328                 l_ptr->reset_checkpoint = l_ptr->next_in_no;
 329                 l_ptr->exp_msg_count = 0;
 330                 tipc_link_reset_fragments(l_ptr);
 331         }
 332
 333         /* Notify subscribers */
 334         tipc_nodesub_notify(n_ptr);
 335
 336         /* Prevent re-contact with node until cleanup is done */
 337
 338         n_ptr->block_setup = WAIT_PEER_DOWN | WAIT_NAMES_GONE;
 339         tipc_k_signal((Handler)node_name_purge_complete, n_ptr->addr);
 340 }
 341
 342 struct sk_buff *tipc_node_get_nodes(const void *req_tlv_area, int req_tlv_space)
 343 {
 344         u32 domain;
 345         struct sk_buff *buf;
 346         struct tipc_node *n_ptr;
 347         struct tipc_node_info node_info;
 348         u32 payload_size;
 349
 350         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_NET_ADDR))
 351                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
 352
 353         domain = ntohl(*(__be32 *)TLV_DATA(req_tlv_area));
 354         if (!tipc_addr_domain_valid(domain))
 355                 return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
 356                                                    " (network address)");
 357
 358         read_lock_bh(&tipc_net_lock);
 359         if (!tipc_num_nodes) {
 360                 read_unlock_bh(&tipc_net_lock);
 361                 return tipc_cfg_reply_none();
 362         }
 363
 364         /* For now, get space for all other nodes */
 365
 366         payload_size = TLV_SPACE(sizeof(node_info)) * tipc_num_nodes;
 367         if (payload_size > 32768u) {
 368                 read_unlock_bh(&tipc_net_lock);
 369                 return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
 370                                                    " (too many nodes)");
 371         }
 372         buf = tipc_cfg_reply_alloc(payload_size);
 373         if (!buf) {
 374                 read_unlock_bh(&tipc_net_lock);
 375                 return NULL;
 376         }
 377
 378         /* Add TLVs for all nodes in scope */
 379
 380         list_for_each_entry(n_ptr, &tipc_node_list, list) {
 381                 if (!tipc_in_scope(domain, n_ptr->addr))
 382                         continue;
 383                 node_info.addr = htonl(n_ptr->addr);
 384                 node_info.up = htonl(tipc_node_is_up(n_ptr));
 385                 tipc_cfg_append_tlv(buf, TIPC_TLV_NODE_INFO,
 386                                     &node_info, sizeof(node_info));
 387         }
 388
 389         read_unlock_bh(&tipc_net_lock);
 390         return buf;
 391 }
 392
 393 struct sk_buff *tipc_node_get_links(const void *req_tlv_area, int req_tlv_space)
 394 {
 395         u32 domain;
 396         struct sk_buff *buf;
 397         struct tipc_node *n_ptr;
 398         struct tipc_link_info link_info;
 399         u32 payload_size;
 400
 401         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_NET_ADDR))
 402                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
 403
 404         domain = ntohl(*(__be32 *)TLV_DATA(req_tlv_area));
 405         if (!tipc_addr_domain_valid(domain))
 406                 return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
 407                                                    " (network address)");
 408
 409         if (!tipc_own_addr)
 410                 return tipc_cfg_reply_none();
 411
 412         read_lock_bh(&tipc_net_lock);
 413
 414         /* Get space for all unicast links + broadcast link */
 415
 416         payload_size = TLV_SPACE(sizeof(link_info)) *
 417                 (atomic_read(&tipc_num_links) + 1);
 418         if (payload_size > 32768u) {
 419                 read_unlock_bh(&tipc_net_lock);
 420                 return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
 421                                                    " (too many links)");
 422         }
 423         buf = tipc_cfg_reply_alloc(payload_size);
 424         if (!buf) {
 425                 read_unlock_bh(&tipc_net_lock);
 426                 return NULL;
 427         }
 428
 429         /* Add TLV for broadcast link */
 430
 431         link_info.dest = htonl(tipc_cluster_mask(tipc_own_addr));
 432         link_info.up = htonl(1);
 433         strlcpy(link_info.str, tipc_bclink_name, TIPC_MAX_LINK_NAME);
 434         tipc_cfg_append_tlv(buf, TIPC_TLV_LINK_INFO, &link_info, sizeof(link_info));
 435
 436         /* Add TLVs for any other links in scope */
 437
 438         list_for_each_entry(n_ptr, &tipc_node_list, list) {
 439                 u32 i;
 440
 441                 if (!tipc_in_scope(domain, n_ptr->addr))
 442                         continue;
 443                 tipc_node_lock(n_ptr);
 444                 for (i = 0; i < MAX_BEARERS; i++) {
 445                         if (!n_ptr->links[i])
 446                                 continue;
 447                         link_info.dest = htonl(n_ptr->addr);
 448                         link_info.up = htonl(tipc_link_is_up(n_ptr->links[i]));
 449                         strcpy(link_info.str, n_ptr->links[i]->name);
 450                         tipc_cfg_append_tlv(buf, TIPC_TLV_LINK_INFO,
 451                                             &link_info, sizeof(link_info));
 452                 }
 453                 tipc_node_unlock(n_ptr);
 454         }
 455
 456         read_unlock_bh(&tipc_net_lock);
 457         return buf;
 458 }