net/tipc/node.c

   1 /*
   2  * net/tipc/node.c: TIPC node management routines
   3  *
   4  * Copyright (c) 2000-2006, 2012 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
  73         if (unlikely(!in_own_cluster_exact(addr)))
  74                 return NULL;
  75
  76         hlist_for_each_entry(node, &node_htable[tipc_hashfn(addr)], hash) {
  77                 if (node->addr == addr)
  78                         return node;
  79         }
  80         return NULL;
  81 }
  82
  83 /**
  84  * tipc_node_create - create neighboring node
  85  *
  86  * Currently, this routine is called by neighbor discovery code, which holds
  87  * net_lock for reading only.  We must take node_create_lock to ensure a node
  88  * isn't created twice if two different bearers discover the node at the same
  89  * time.  (It would be preferable to switch to holding net_lock in write mode,
  90  * but this is a non-trivial change.)
  91  */
  92 struct tipc_node *tipc_node_create(u32 addr)
  93 {
  94         struct tipc_node *n_ptr, *temp_node;
  95
  96         spin_lock_bh(&node_create_lock);
  97
  98         n_ptr = tipc_node_find(addr);
  99         if (n_ptr) {
 100                 spin_unlock_bh(&node_create_lock);
 101                 return n_ptr;
 102         }
 103
 104         n_ptr = kzalloc(sizeof(*n_ptr), GFP_ATOMIC);
 105         if (!n_ptr) {
 106                 spin_unlock_bh(&node_create_lock);
 107                 pr_warn("Node creation failed, no memory\n");
 108                 return NULL;
 109         }
 110
 111         n_ptr->addr = addr;
 112         spin_lock_init(&n_ptr->lock);
 113         INIT_HLIST_NODE(&n_ptr->hash);
 114         INIT_LIST_HEAD(&n_ptr->list);
 115         INIT_LIST_HEAD(&n_ptr->nsub);
 116
 117         hlist_add_head(&n_ptr->hash, &node_htable[tipc_hashfn(addr)]);
 118
 119         list_for_each_entry(temp_node, &tipc_node_list, list) {
 120                 if (n_ptr->addr < temp_node->addr)
 121                         break;
 122         }
 123         list_add_tail(&n_ptr->list, &temp_node->list);
 124         n_ptr->block_setup = WAIT_PEER_DOWN;
 125         n_ptr->signature = INVALID_NODE_SIG;
 126
 127         tipc_num_nodes++;
 128
 129         spin_unlock_bh(&node_create_lock);
 130         return n_ptr;
 131 }
 132
 133 void tipc_node_delete(struct tipc_node *n_ptr)
 134 {
 135         list_del(&n_ptr->list);
 136         hlist_del(&n_ptr->hash);
 137         kfree(n_ptr);
 138
 139         tipc_num_nodes--;
 140 }
 141
 142 /**
 143  * tipc_node_link_up - handle addition of link
 144  *
 145  * Link becomes active (alone or shared) or standby, depending on its priority.
 146  */
 147 void tipc_node_link_up(struct tipc_node *n_ptr, struct tipc_link *l_ptr)
 148 {
 149         struct tipc_link **active = &n_ptr->active_links[0];
 150
 151         n_ptr->working_links++;
 152
 153         pr_info("Established link <%s> on network plane %c\n",
 154                 l_ptr->name, l_ptr->b_ptr->net_plane);
 155
 156         if (!active[0]) {
 157                 active[0] = active[1] = l_ptr;
 158                 node_established_contact(n_ptr);
 159                 return;
 160         }
 161         if (l_ptr->priority < active[0]->priority) {
 162                 pr_info("New link <%s> becomes standby\n", l_ptr->name);
 163                 return;
 164         }
 165         tipc_link_send_duplicate(active[0], l_ptr);
 166         if (l_ptr->priority == active[0]->priority) {
 167                 active[0] = l_ptr;
 168                 return;
 169         }
 170         pr_info("Old link <%s> becomes standby\n", active[0]->name);
 171         if (active[1] != active[0])
 172                 pr_info("Old link <%s> becomes standby\n", active[1]->name);
 173         active[0] = active[1] = l_ptr;
 174 }
 175
 176 /**
 177  * node_select_active_links - select active link
 178  */
 179 static void node_select_active_links(struct tipc_node *n_ptr)
 180 {
 181         struct tipc_link **active = &n_ptr->active_links[0];
 182         u32 i;
 183         u32 highest_prio = 0;
 184
 185         active[0] = active[1] = NULL;
 186
 187         for (i = 0; i < MAX_BEARERS; i++) {
 188                 struct tipc_link *l_ptr = n_ptr->links[i];
 189
 190                 if (!l_ptr || !tipc_link_is_up(l_ptr) ||
 191                     (l_ptr->priority < highest_prio))
 192                         continue;
 193
 194                 if (l_ptr->priority > highest_prio) {
 195                         highest_prio = l_ptr->priority;
 196                         active[0] = active[1] = l_ptr;
 197                 } else {
 198                         active[1] = l_ptr;
 199                 }
 200         }
 201 }
 202
 203 /**
 204  * tipc_node_link_down - handle loss of link
 205  */
 206 void tipc_node_link_down(struct tipc_node *n_ptr, struct tipc_link *l_ptr)
 207 {
 208         struct tipc_link **active;
 209
 210         n_ptr->working_links--;
 211
 212         if (!tipc_link_is_active(l_ptr)) {
 213                 pr_info("Lost standby link <%s> on network plane %c\n",
 214                         l_ptr->name, l_ptr->b_ptr->net_plane);
 215                 return;
 216         }
 217         pr_info("Lost link <%s> on network plane %c\n",
 218                 l_ptr->name, l_ptr->b_ptr->net_plane);
 219
 220         active = &n_ptr->active_links[0];
 221         if (active[0] == l_ptr)
 222                 active[0] = active[1];
 223         if (active[1] == l_ptr)
 224                 active[1] = active[0];
 225         if (active[0] == l_ptr)
 226                 node_select_active_links(n_ptr);
 227         if (tipc_node_is_up(n_ptr))
 228                 tipc_link_changeover(l_ptr);
 229         else
 230                 node_lost_contact(n_ptr);
 231 }
 232
 233 int tipc_node_active_links(struct tipc_node *n_ptr)
 234 {
 235         return n_ptr->active_links[0] != NULL;
 236 }
 237
 238 int tipc_node_redundant_links(struct tipc_node *n_ptr)
 239 {
 240         return n_ptr->working_links > 1;
 241 }
 242
 243 int tipc_node_is_up(struct tipc_node *n_ptr)
 244 {
 245         return tipc_node_active_links(n_ptr);
 246 }
 247
 248 void tipc_node_attach_link(struct tipc_node *n_ptr, struct tipc_link *l_ptr)
 249 {
 250         n_ptr->links[l_ptr->b_ptr->identity] = l_ptr;
 251         atomic_inc(&tipc_num_links);
 252         n_ptr->link_cnt++;
 253 }
 254
 255 void tipc_node_detach_link(struct tipc_node *n_ptr, struct tipc_link *l_ptr)
 256 {
 257         n_ptr->links[l_ptr->b_ptr->identity] = NULL;
 258         atomic_dec(&tipc_num_links);
 259         n_ptr->link_cnt--;
 260 }
 261
 262 static void node_established_contact(struct tipc_node *n_ptr)
 263 {
 264         tipc_k_signal((Handler)tipc_named_node_up, n_ptr->addr);
 265         n_ptr->bclink.oos_state = 0;
 266         n_ptr->bclink.acked = tipc_bclink_get_last_sent();
 267         tipc_bclink_add_node(n_ptr->addr);
 268 }
 269
 270 static void node_name_purge_complete(unsigned long node_addr)
 271 {
 272         struct tipc_node *n_ptr;
 273
 274         read_lock_bh(&tipc_net_lock);
 275         n_ptr = tipc_node_find(node_addr);
 276         if (n_ptr) {
 277                 tipc_node_lock(n_ptr);
 278                 n_ptr->block_setup &= ~WAIT_NAMES_GONE;
 279                 tipc_node_unlock(n_ptr);
 280         }
 281         read_unlock_bh(&tipc_net_lock);
 282 }
 283
 284 static void node_lost_contact(struct tipc_node *n_ptr)
 285 {
 286         char addr_string[16];
 287         u32 i;
 288
 289         pr_info("Lost contact with %s\n",
 290                 tipc_addr_string_fill(addr_string, n_ptr->addr));
 291
 292         /* Flush broadcast link info associated with lost node */
 293         if (n_ptr->bclink.recv_permitted) {
 294                 while (n_ptr->bclink.deferred_head) {
 295                         struct sk_buff *buf = n_ptr->bclink.deferred_head;
 296                         n_ptr->bclink.deferred_head = buf->next;
 297                         kfree_skb(buf);
 298                 }
 299                 n_ptr->bclink.deferred_size = 0;
 300
 301                 if (n_ptr->bclink.defragm) {
 302                         kfree_skb(n_ptr->bclink.defragm);
 303                         n_ptr->bclink.defragm = NULL;
 304                 }
 305
 306                 tipc_bclink_remove_node(n_ptr->addr);
 307                 tipc_bclink_acknowledge(n_ptr, INVALID_LINK_SEQ);
 308
 309                 n_ptr->bclink.recv_permitted = false;
 310         }
 311
 312         /* Abort link changeover */
 313         for (i = 0; i < MAX_BEARERS; i++) {
 314                 struct tipc_link *l_ptr = n_ptr->links[i];
 315                 if (!l_ptr)
 316                         continue;
 317                 l_ptr->reset_checkpoint = l_ptr->next_in_no;
 318                 l_ptr->exp_msg_count = 0;
 319                 tipc_link_reset_fragments(l_ptr);
 320         }
 321
 322         /* Notify subscribers */
 323         tipc_nodesub_notify(n_ptr);
 324
 325         /* Prevent re-contact with node until cleanup is done */
 326         n_ptr->block_setup = WAIT_PEER_DOWN | WAIT_NAMES_GONE;
 327         tipc_k_signal((Handler)node_name_purge_complete, n_ptr->addr);
 328 }
 329
 330 struct sk_buff *tipc_node_get_nodes(const void *req_tlv_area, int req_tlv_space)
 331 {
 332         u32 domain;
 333         struct sk_buff *buf;
 334         struct tipc_node *n_ptr;
 335         struct tipc_node_info node_info;
 336         u32 payload_size;
 337
 338         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_NET_ADDR))
 339                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
 340
 341         domain = ntohl(*(__be32 *)TLV_DATA(req_tlv_area));
 342         if (!tipc_addr_domain_valid(domain))
 343                 return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
 344                                                    " (network address)");
 345
 346         read_lock_bh(&tipc_net_lock);
 347         if (!tipc_num_nodes) {
 348                 read_unlock_bh(&tipc_net_lock);
 349                 return tipc_cfg_reply_none();
 350         }
 351
 352         /* For now, get space for all other nodes */
 353         payload_size = TLV_SPACE(sizeof(node_info)) * tipc_num_nodes;
 354         if (payload_size > 32768u) {
 355                 read_unlock_bh(&tipc_net_lock);
 356                 return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
 357                                                    " (too many nodes)");
 358         }
 359         buf = tipc_cfg_reply_alloc(payload_size);
 360         if (!buf) {
 361                 read_unlock_bh(&tipc_net_lock);
 362                 return NULL;
 363         }
 364
 365         /* Add TLVs for all nodes in scope */
 366         list_for_each_entry(n_ptr, &tipc_node_list, list) {
 367                 if (!tipc_in_scope(domain, n_ptr->addr))
 368                         continue;
 369                 node_info.addr = htonl(n_ptr->addr);
 370                 node_info.up = htonl(tipc_node_is_up(n_ptr));
 371                 tipc_cfg_append_tlv(buf, TIPC_TLV_NODE_INFO,
 372                                     &node_info, sizeof(node_info));
 373         }
 374
 375         read_unlock_bh(&tipc_net_lock);
 376         return buf;
 377 }
 378
 379 struct sk_buff *tipc_node_get_links(const void *req_tlv_area, int req_tlv_space)
 380 {
 381         u32 domain;
 382         struct sk_buff *buf;
 383         struct tipc_node *n_ptr;
 384         struct tipc_link_info link_info;
 385         u32 payload_size;
 386
 387         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_NET_ADDR))
 388                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
 389
 390         domain = ntohl(*(__be32 *)TLV_DATA(req_tlv_area));
 391         if (!tipc_addr_domain_valid(domain))
 392                 return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
 393                                                    " (network address)");
 394
 395         if (!tipc_own_addr)
 396                 return tipc_cfg_reply_none();
 397
 398         read_lock_bh(&tipc_net_lock);
 399
 400         /* Get space for all unicast links + broadcast link */
 401         payload_size = TLV_SPACE(sizeof(link_info)) *
 402                 (atomic_read(&tipc_num_links) + 1);
 403         if (payload_size > 32768u) {
 404                 read_unlock_bh(&tipc_net_lock);
 405                 return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
 406                                                    " (too many links)");
 407         }
 408         buf = tipc_cfg_reply_alloc(payload_size);
 409         if (!buf) {
 410                 read_unlock_bh(&tipc_net_lock);
 411                 return NULL;
 412         }
 413
 414         /* Add TLV for broadcast link */
 415         link_info.dest = htonl(tipc_cluster_mask(tipc_own_addr));
 416         link_info.up = htonl(1);
 417         strlcpy(link_info.str, tipc_bclink_name, TIPC_MAX_LINK_NAME);
 418         tipc_cfg_append_tlv(buf, TIPC_TLV_LINK_INFO, &link_info, sizeof(link_info));
 419
 420         /* Add TLVs for any other links in scope */
 421         list_for_each_entry(n_ptr, &tipc_node_list, list) {
 422                 u32 i;
 423
 424                 if (!tipc_in_scope(domain, n_ptr->addr))
 425                         continue;
 426                 tipc_node_lock(n_ptr);
 427                 for (i = 0; i < MAX_BEARERS; i++) {
 428                         if (!n_ptr->links[i])
 429                                 continue;
 430                         link_info.dest = htonl(n_ptr->addr);
 431                         link_info.up = htonl(tipc_link_is_up(n_ptr->links[i]));
 432                         strcpy(link_info.str, n_ptr->links[i]->name);
 433                         tipc_cfg_append_tlv(buf, TIPC_TLV_LINK_INFO,
 434                                             &link_info, sizeof(link_info));
 435                 }
 436                 tipc_node_unlock(n_ptr);
 437         }
 438
 439         read_unlock_bh(&tipc_net_lock);
 440         return buf;
 441 }