linux/net/tipc/name_distr.c
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   1/*
   2 * net/tipc/name_distr.c: TIPC name distribution code
   3 *
   4 * Copyright (c) 2000-2006, Ericsson AB
   5 * Copyright (c) 2005, 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 "cluster.h"
  39#include "dbg.h"
  40#include "link.h"
  41#include "msg.h"
  42#include "name_distr.h"
  43
  44#define ITEM_SIZE sizeof(struct distr_item)
  45
  46/**
  47 * struct distr_item - publication info distributed to other nodes
  48 * @type: name sequence type
  49 * @lower: name sequence lower bound
  50 * @upper: name sequence upper bound
  51 * @ref: publishing port reference
  52 * @key: publication key
  53 *
  54 * ===> All fields are stored in network byte order. <===
  55 *
  56 * First 3 fields identify (name or) name sequence being published.
  57 * Reference field uniquely identifies port that published name sequence.
  58 * Key field uniquely identifies publication, in the event a port has
  59 * multiple publications of the same name sequence.
  60 *
  61 * Note: There is no field that identifies the publishing node because it is
  62 * the same for all items contained within a publication message.
  63 */
  64
  65struct distr_item {
  66        __be32 type;
  67        __be32 lower;
  68        __be32 upper;
  69        __be32 ref;
  70        __be32 key;
  71};
  72
  73/**
  74 * List of externally visible publications by this node --
  75 * that is, all publications having scope > TIPC_NODE_SCOPE.
  76 */
  77
  78static LIST_HEAD(publ_root);
  79static u32 publ_cnt = 0;
  80
  81/**
  82 * publ_to_item - add publication info to a publication message
  83 */
  84
  85static void publ_to_item(struct distr_item *i, struct publication *p)
  86{
  87        i->type = htonl(p->type);
  88        i->lower = htonl(p->lower);
  89        i->upper = htonl(p->upper);
  90        i->ref = htonl(p->ref);
  91        i->key = htonl(p->key);
  92        dbg("publ_to_item: %u, %u, %u\n", p->type, p->lower, p->upper);
  93}
  94
  95/**
  96 * named_prepare_buf - allocate & initialize a publication message
  97 */
  98
  99static struct sk_buff *named_prepare_buf(u32 type, u32 size, u32 dest)
 100{
 101        struct sk_buff *buf = buf_acquire(LONG_H_SIZE + size);
 102        struct tipc_msg *msg;
 103
 104        if (buf != NULL) {
 105                msg = buf_msg(buf);
 106                msg_init(msg, NAME_DISTRIBUTOR, type, LONG_H_SIZE, dest);
 107                msg_set_size(msg, LONG_H_SIZE + size);
 108        }
 109        return buf;
 110}
 111
 112/**
 113 * tipc_named_publish - tell other nodes about a new publication by this node
 114 */
 115
 116void tipc_named_publish(struct publication *publ)
 117{
 118        struct sk_buff *buf;
 119        struct distr_item *item;
 120
 121        list_add_tail(&publ->local_list, &publ_root);
 122        publ_cnt++;
 123
 124        buf = named_prepare_buf(PUBLICATION, ITEM_SIZE, 0);
 125        if (!buf) {
 126                warn("Publication distribution failure\n");
 127                return;
 128        }
 129
 130        item = (struct distr_item *)msg_data(buf_msg(buf));
 131        publ_to_item(item, publ);
 132        dbg("tipc_named_withdraw: broadcasting publish msg\n");
 133        tipc_cltr_broadcast(buf);
 134}
 135
 136/**
 137 * tipc_named_withdraw - tell other nodes about a withdrawn publication by this node
 138 */
 139
 140void tipc_named_withdraw(struct publication *publ)
 141{
 142        struct sk_buff *buf;
 143        struct distr_item *item;
 144
 145        list_del(&publ->local_list);
 146        publ_cnt--;
 147
 148        buf = named_prepare_buf(WITHDRAWAL, ITEM_SIZE, 0);
 149        if (!buf) {
 150                warn("Withdrawl distribution failure\n");
 151                return;
 152        }
 153
 154        item = (struct distr_item *)msg_data(buf_msg(buf));
 155        publ_to_item(item, publ);
 156        dbg("tipc_named_withdraw: broadcasting withdraw msg\n");
 157        tipc_cltr_broadcast(buf);
 158}
 159
 160/**
 161 * tipc_named_node_up - tell specified node about all publications by this node
 162 */
 163
 164void tipc_named_node_up(unsigned long node)
 165{
 166        struct publication *publ;
 167        struct distr_item *item = NULL;
 168        struct sk_buff *buf = NULL;
 169        u32 left = 0;
 170        u32 rest;
 171        u32 max_item_buf;
 172
 173        read_lock_bh(&tipc_nametbl_lock);
 174        max_item_buf = TIPC_MAX_USER_MSG_SIZE / ITEM_SIZE;
 175        max_item_buf *= ITEM_SIZE;
 176        rest = publ_cnt * ITEM_SIZE;
 177
 178        list_for_each_entry(publ, &publ_root, local_list) {
 179                if (!buf) {
 180                        left = (rest <= max_item_buf) ? rest : max_item_buf;
 181                        rest -= left;
 182                        buf = named_prepare_buf(PUBLICATION, left, node);
 183                        if (!buf) {
 184                                warn("Bulk publication distribution failure\n");
 185                                goto exit;
 186                        }
 187                        item = (struct distr_item *)msg_data(buf_msg(buf));
 188                }
 189                publ_to_item(item, publ);
 190                item++;
 191                left -= ITEM_SIZE;
 192                if (!left) {
 193                        msg_set_link_selector(buf_msg(buf), node);
 194                        dbg("tipc_named_node_up: sending publish msg to "
 195                            "<%u.%u.%u>\n", tipc_zone(node),
 196                            tipc_cluster(node), tipc_node(node));
 197                        tipc_link_send(buf, node, node);
 198                        buf = NULL;
 199                }
 200        }
 201exit:
 202        read_unlock_bh(&tipc_nametbl_lock);
 203}
 204
 205/**
 206 * node_is_down - remove publication associated with a failed node
 207 *
 208 * Invoked for each publication issued by a newly failed node.
 209 * Removes publication structure from name table & deletes it.
 210 * In rare cases the link may have come back up again when this
 211 * function is called, and we have two items representing the same
 212 * publication. Nudge this item's key to distinguish it from the other.
 213 * (Note: Publication's node subscription is already unsubscribed.)
 214 */
 215
 216static void node_is_down(struct publication *publ)
 217{
 218        struct publication *p;
 219
 220        write_lock_bh(&tipc_nametbl_lock);
 221        dbg("node_is_down: withdrawing %u, %u, %u\n",
 222            publ->type, publ->lower, publ->upper);
 223        publ->key += 1222345;
 224        p = tipc_nametbl_remove_publ(publ->type, publ->lower,
 225                                     publ->node, publ->ref, publ->key);
 226        write_unlock_bh(&tipc_nametbl_lock);
 227
 228        if (p != publ) {
 229                err("Unable to remove publication from failed node\n"
 230                    "(type=%u, lower=%u, node=0x%x, ref=%u, key=%u)\n",
 231                    publ->type, publ->lower, publ->node, publ->ref, publ->key);
 232        }
 233
 234        if (p) {
 235                kfree(p);
 236        }
 237}
 238
 239/**
 240 * tipc_named_recv - process name table update message sent by another node
 241 */
 242
 243void tipc_named_recv(struct sk_buff *buf)
 244{
 245        struct publication *publ;
 246        struct tipc_msg *msg = buf_msg(buf);
 247        struct distr_item *item = (struct distr_item *)msg_data(msg);
 248        u32 count = msg_data_sz(msg) / ITEM_SIZE;
 249
 250        write_lock_bh(&tipc_nametbl_lock);
 251        while (count--) {
 252                if (msg_type(msg) == PUBLICATION) {
 253                        dbg("tipc_named_recv: got publication for %u, %u, %u\n",
 254                            ntohl(item->type), ntohl(item->lower),
 255                            ntohl(item->upper));
 256                        publ = tipc_nametbl_insert_publ(ntohl(item->type),
 257                                                        ntohl(item->lower),
 258                                                        ntohl(item->upper),
 259                                                        TIPC_CLUSTER_SCOPE,
 260                                                        msg_orignode(msg),
 261                                                        ntohl(item->ref),
 262                                                        ntohl(item->key));
 263                        if (publ) {
 264                                tipc_nodesub_subscribe(&publ->subscr,
 265                                                       msg_orignode(msg),
 266                                                       publ,
 267                                                       (net_ev_handler)node_is_down);
 268                        }
 269                } else if (msg_type(msg) == WITHDRAWAL) {
 270                        dbg("tipc_named_recv: got withdrawl for %u, %u, %u\n",
 271                            ntohl(item->type), ntohl(item->lower),
 272                            ntohl(item->upper));
 273                        publ = tipc_nametbl_remove_publ(ntohl(item->type),
 274                                                        ntohl(item->lower),
 275                                                        msg_orignode(msg),
 276                                                        ntohl(item->ref),
 277                                                        ntohl(item->key));
 278
 279                        if (publ) {
 280                                tipc_nodesub_unsubscribe(&publ->subscr);
 281                                kfree(publ);
 282                        } else {
 283                                err("Unable to remove publication by node 0x%x\n"
 284                                    "(type=%u, lower=%u, ref=%u, key=%u)\n",
 285                                    msg_orignode(msg),
 286                                    ntohl(item->type), ntohl(item->lower),
 287                                    ntohl(item->ref), ntohl(item->key));
 288                        }
 289                } else {
 290                        warn("Unrecognized name table message received\n");
 291                }
 292                item++;
 293        }
 294        write_unlock_bh(&tipc_nametbl_lock);
 295        buf_discard(buf);
 296}
 297
 298/**
 299 * tipc_named_reinit - re-initialize local publication list
 300 *
 301 * This routine is called whenever TIPC networking is (re)enabled.
 302 * All existing publications by this node that have "cluster" or "zone" scope
 303 * are updated to reflect the node's current network address.
 304 * (If the node's address is unchanged, the update loop terminates immediately.)
 305 */
 306
 307void tipc_named_reinit(void)
 308{
 309        struct publication *publ;
 310
 311        write_lock_bh(&tipc_nametbl_lock);
 312        list_for_each_entry(publ, &publ_root, local_list) {
 313                if (publ->node == tipc_own_addr)
 314                        break;
 315                publ->node = tipc_own_addr;
 316        }
 317        write_unlock_bh(&tipc_nametbl_lock);
 318}
 319