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