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         /* Syncronize broadcast acks */
 274         n_ptr->bclink.acked = tipc_bclink_get_last_sent();
 275
 276         if (n_ptr->bclink.supportable) {
 277                 tipc_bclink_add_node(n_ptr->addr);
 278                 n_ptr->bclink.supported = 1;
 279         }
 280 }
 281
 282 static void node_name_purge_complete(unsigned long node_addr)
 283 {
 284         struct tipc_node *n_ptr;
 285
 286         read_lock_bh(&tipc_net_lock);
 287         n_ptr = tipc_node_find(node_addr);
 288         if (n_ptr) {
 289                 tipc_node_lock(n_ptr);
 290                 n_ptr->block_setup &= ~WAIT_NAMES_GONE;
 291                 tipc_node_unlock(n_ptr);
 292         }
 293         read_unlock_bh(&tipc_net_lock);
 294 }
 295
 296 static void node_lost_contact(struct tipc_node *n_ptr)
 297 {
 298         char addr_string[16];
 299         u32 i;
 300
 301         info("Lost contact with %s\n",
 302              tipc_addr_string_fill(addr_string, n_ptr->addr));
 303
 304         /* Flush broadcast link info associated with lost node */
 305
 306         if (n_ptr->bclink.supported) {
 307                 while (n_ptr->bclink.deferred_head) {
 308                         struct sk_buff *buf = n_ptr->bclink.deferred_head;
 309                         n_ptr->bclink.deferred_head = buf->next;
 310                         kfree_skb(buf);
 311                 }
 312                 n_ptr->bclink.deferred_size = 0;
 313
 314                 if (n_ptr->bclink.defragm) {
 315                         kfree_skb(n_ptr->bclink.defragm);
 316                         n_ptr->bclink.defragm = NULL;
 317                 }
 318
 319                 tipc_bclink_remove_node(n_ptr->addr);
 320                 tipc_bclink_acknowledge(n_ptr, INVALID_LINK_SEQ);
 321
 322                 n_ptr->bclink.supported = 0;
 323         }
 324
 325         /* Abort link changeover */
 326         for (i = 0; i < MAX_BEARERS; i++) {
 327                 struct tipc_link *l_ptr = n_ptr->links[i];
 328                 if (!l_ptr)
 329                         continue;
 330                 l_ptr->reset_checkpoint = l_ptr->next_in_no;
 331                 l_ptr->exp_msg_count = 0;
 332                 tipc_link_reset_fragments(l_ptr);
 333         }
 334
 335         /* Notify subscribers */
 336         tipc_nodesub_notify(n_ptr);
 337
 338         /* Prevent re-contact with node until cleanup is done */
 339
 340         n_ptr->block_setup = WAIT_PEER_DOWN | WAIT_NAMES_GONE;
 341         tipc_k_signal((Handler)node_name_purge_complete, n_ptr->addr);
 342 }
 343
 344 struct sk_buff *tipc_node_get_nodes(const void *req_tlv_area, int req_tlv_space)
 345 {
 346         u32 domain;
 347         struct sk_buff *buf;
 348         struct tipc_node *n_ptr;
 349         struct tipc_node_info node_info;
 350         u32 payload_size;
 351
 352         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_NET_ADDR))
 353                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
 354
 355         domain = ntohl(*(__be32 *)TLV_DATA(req_tlv_area));
 356         if (!tipc_addr_domain_valid(domain))
 357                 return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
 358                                                    " (network address)");
 359
 360         read_lock_bh(&tipc_net_lock);
 361         if (!tipc_num_nodes) {
 362                 read_unlock_bh(&tipc_net_lock);
 363                 return tipc_cfg_reply_none();
 364         }
 365
 366         /* For now, get space for all other nodes */
 367
 368         payload_size = TLV_SPACE(sizeof(node_info)) * tipc_num_nodes;
 369         if (payload_size > 32768u) {
 370                 read_unlock_bh(&tipc_net_lock);
 371                 return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
 372                                                    " (too many nodes)");
 373         }
 374         buf = tipc_cfg_reply_alloc(payload_size);
 375         if (!buf) {
 376                 read_unlock_bh(&tipc_net_lock);
 377                 return NULL;
 378         }
 379
 380         /* Add TLVs for all nodes in scope */
 381
 382         list_for_each_entry(n_ptr, &tipc_node_list, list) {
 383                 if (!tipc_in_scope(domain, n_ptr->addr))
 384                         continue;
 385                 node_info.addr = htonl(n_ptr->addr);
 386                 node_info.up = htonl(tipc_node_is_up(n_ptr));
 387                 tipc_cfg_append_tlv(buf, TIPC_TLV_NODE_INFO,
 388                                     &node_info, sizeof(node_info));
 389         }
 390
 391         read_unlock_bh(&tipc_net_lock);
 392         return buf;
 393 }
 394
 395 struct sk_buff *tipc_node_get_links(const void *req_tlv_area, int req_tlv_space)
 396 {
 397         u32 domain;
 398         struct sk_buff *buf;
 399         struct tipc_node *n_ptr;
 400         struct tipc_link_info link_info;
 401         u32 payload_size;
 402
 403         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_NET_ADDR))
 404                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
 405
 406         domain = ntohl(*(__be32 *)TLV_DATA(req_tlv_area));
 407         if (!tipc_addr_domain_valid(domain))
 408                 return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
 409                                                    " (network address)");
 410
 411         if (tipc_mode != TIPC_NET_MODE)
 412                 return tipc_cfg_reply_none();
 413
 414         read_lock_bh(&tipc_net_lock);
 415
 416         /* Get space for all unicast links + broadcast link */
 417
 418         payload_size = TLV_SPACE(sizeof(link_info)) *
 419                 (atomic_read(&tipc_num_links) + 1);
 420         if (payload_size > 32768u) {
 421                 read_unlock_bh(&tipc_net_lock);
 422                 return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
 423                                                    " (too many links)");
 424         }
 425         buf = tipc_cfg_reply_alloc(payload_size);
 426         if (!buf) {
 427                 read_unlock_bh(&tipc_net_lock);
 428                 return NULL;
 429         }
 430
 431         /* Add TLV for broadcast link */
 432
 433         link_info.dest = htonl(tipc_cluster_mask(tipc_own_addr));
 434         link_info.up = htonl(1);
 435         strlcpy(link_info.str, tipc_bclink_name, TIPC_MAX_LINK_NAME);
 436         tipc_cfg_append_tlv(buf, TIPC_TLV_LINK_INFO, &link_info, sizeof(link_info));
 437
 438         /* Add TLVs for any other links in scope */
 439
 440         list_for_each_entry(n_ptr, &tipc_node_list, list) {
 441                 u32 i;
 442
 443                 if (!tipc_in_scope(domain, n_ptr->addr))
 444                         continue;
 445                 tipc_node_lock(n_ptr);
 446                 for (i = 0; i < MAX_BEARERS; i++) {
 447                         if (!n_ptr->links[i])
 448                                 continue;
 449                         link_info.dest = htonl(n_ptr->addr);
 450                         link_info.up = htonl(tipc_link_is_up(n_ptr->links[i]));
 451                         strcpy(link_info.str, n_ptr->links[i]->name);
 452                         tipc_cfg_append_tlv(buf, TIPC_TLV_LINK_INFO,
 453                                             &link_info, sizeof(link_info));
 454                 }
 455                 tipc_node_unlock(n_ptr);
 456         }
 457
 458         read_unlock_bh(&tipc_net_lock);
 459         return buf;
 460 }