/*
 * net/tipc/name_distr.c: TIPC name distribution code
 *
 * Copyright (c) 2000-2006, Ericsson AB
 * Copyright (c) 2005, Wind River Systems
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the names of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include "core.h"
#include "cluster.h"
#include "dbg.h"
#include "link.h"
#include "msg.h"
#include "name_distr.h"

#define ITEM_SIZE sizeof(struct distr_item)

/**
 * struct distr_item - publication info distributed to other nodes
 * @type: name sequence type
 * @lower: name sequence lower bound
 * @upper: name sequence upper bound
 * @ref: publishing port reference
 * @key: publication key
 *
 * ===> All fields are stored in network byte order. <===
 *
 * First 3 fields identify (name or) name sequence being published.
 * Reference field uniquely identifies port that published name sequence.
 * Key field uniquely identifies publication, in the event a port has
 * multiple publications of the same name sequence.
 *
 * Note: There is no field that identifies the publishing node because it is
 * the same for all items contained within a publication message.
 */

struct distr_item {
        __be32 type;
        __be32 lower;
        __be32 upper;
        __be32 ref;
        __be32 key;
};

/**
 * List of externally visible publications by this node --
 * that is, all publications having scope > TIPC_NODE_SCOPE.
 */

static LIST_HEAD(publ_root);
static u32 publ_cnt = 0;

/**
 * publ_to_item - add publication info to a publication message
 */

static void publ_to_item(struct distr_item *i, struct publication *p)
{
        i->type = htonl(p->type);
        i->lower = htonl(p->lower);
        i->upper = htonl(p->upper);
        i->ref = htonl(p->ref);
        i->key = htonl(p->key);
        dbg("publ_to_item: %u, %u, %u\n", p->type, p->lower, p->upper);
}

/**
 * named_prepare_buf - allocate & initialize a publication message
 */

static struct sk_buff *named_prepare_buf(u32 type, u32 size, u32 dest)
{
        struct sk_buff *buf = buf_acquire(LONG_H_SIZE + size);
        struct tipc_msg *msg;

        if (buf != NULL) {
                msg = buf_msg(buf);
                msg_init(msg, NAME_DISTRIBUTOR, type, LONG_H_SIZE, dest);
                msg_set_size(msg, LONG_H_SIZE + size);
        }
        return buf;
}

/**
 * tipc_named_publish - tell other nodes about a new publication by this node
 */

void tipc_named_publish(struct publication *publ)
{
        struct sk_buff *buf;
        struct distr_item *item;

        list_add_tail(&publ->local_list, &publ_root);
        publ_cnt++;

        buf = named_prepare_buf(PUBLICATION, ITEM_SIZE, 0);
        if (!buf) {
                warn("Publication distribution failure\n");
                return;
        }

        item = (struct distr_item *)msg_data(buf_msg(buf));
        publ_to_item(item, publ);
        dbg("tipc_named_withdraw: broadcasting publish msg\n");
        tipc_cltr_broadcast(buf);
}

/**
 * tipc_named_withdraw - tell other nodes about a withdrawn publication by this node
 */

void tipc_named_withdraw(struct publication *publ)
{
        struct sk_buff *buf;
        struct distr_item *item;

        list_del(&publ->local_list);
        publ_cnt--;

        buf = named_prepare_buf(WITHDRAWAL, ITEM_SIZE, 0);
        if (!buf) {
                warn("Withdrawl distribution failure\n");
                return;
        }

        item = (struct distr_item *)msg_data(buf_msg(buf));
        publ_to_item(item, publ);
        dbg("tipc_named_withdraw: broadcasting withdraw msg\n");
        tipc_cltr_broadcast(buf);
}

/**
 * tipc_named_node_up - tell specified node about all publications by this node
 */

void tipc_named_node_up(unsigned long node)
{
        struct publication *publ;
        struct distr_item *item = NULL;
        struct sk_buff *buf = NULL;
        u32 left = 0;
        u32 rest;
        u32 max_item_buf;

        read_lock_bh(&tipc_nametbl_lock);
        max_item_buf = TIPC_MAX_USER_MSG_SIZE / ITEM_SIZE;
        max_item_buf *= ITEM_SIZE;
        rest = publ_cnt * ITEM_SIZE;

        list_for_each_entry(publ, &publ_root, local_list) {
                if (!buf) {
                        left = (rest <= max_item_buf) ? rest : max_item_buf;
                        rest -= left;
                        buf = named_prepare_buf(PUBLICATION, left, node);
                        if (!buf) {
                                warn("Bulk publication distribution failure\n");
                                goto exit;
                        }
                        item = (struct distr_item *)msg_data(buf_msg(buf));
                }
                publ_to_item(item, publ);
                item++;
                left -= ITEM_SIZE;
                if (!left) {
                        msg_set_link_selector(buf_msg(buf), node);
                        dbg("tipc_named_node_up: sending publish msg to "
                            "<%u.%u.%u>\n", tipc_zone(node),
                            tipc_cluster(node), tipc_node(node));
                        tipc_link_send(buf, node, node);
                        buf = NULL;
                }
        }
exit:
        read_unlock_bh(&tipc_nametbl_lock);
}

/**
 * node_is_down - remove publication associated with a failed node
 *
 * Invoked for each publication issued by a newly failed node.
 * Removes publication structure from name table & deletes it.
 * In rare cases the link may have come back up again when this
 * function is called, and we have two items representing the same
 * publication. Nudge this item's key to distinguish it from the other.
 * (Note: Publication's node subscription is already unsubscribed.)
 */

static void node_is_down(struct publication *publ)
{
        struct publication *p;

        write_lock_bh(&tipc_nametbl_lock);
        dbg("node_is_down: withdrawing %u, %u, %u\n",
            publ->type, publ->lower, publ->upper);
        publ->key += 1222345;
        p = tipc_nametbl_remove_publ(publ->type, publ->lower,
                                     publ->node, publ->ref, publ->key);
        write_unlock_bh(&tipc_nametbl_lock);

        if (p != publ) {
                err("Unable to remove publication from failed node\n"
                    "(type=%u, lower=%u, node=0x%x, ref=%u, key=%u)\n",
                    publ->type, publ->lower, publ->node, publ->ref, publ->key);
        }

        if (p) {
                kfree(p);
        }
}

/**
 * tipc_named_recv - process name table update message sent by another node
 */

void tipc_named_recv(struct sk_buff *buf)
{
        struct publication *publ;
        struct tipc_msg *msg = buf_msg(buf);
        struct distr_item *item = (struct distr_item *)msg_data(msg);
        u32 count = msg_data_sz(msg) / ITEM_SIZE;

        write_lock_bh(&tipc_nametbl_lock);
        while (count--) {
                if (msg_type(msg) == PUBLICATION) {
                        dbg("tipc_named_recv: got publication for %u, %u, %u\n",
                            ntohl(item->type), ntohl(item->lower),
                            ntohl(item->upper));
                        publ = tipc_nametbl_insert_publ(ntohl(item->type),
                                                        ntohl(item->lower),
                                                        ntohl(item->upper),
                                                        TIPC_CLUSTER_SCOPE,
                                                        msg_orignode(msg),
                                                        ntohl(item->ref),
                                                        ntohl(item->key));
                        if (publ) {
                                tipc_nodesub_subscribe(&publ->subscr,
                                                       msg_orignode(msg),
                                                       publ,
                                                       (net_ev_handler)node_is_down);
                        }
                } else if (msg_type(msg) == WITHDRAWAL) {
                        dbg("tipc_named_recv: got withdrawl for %u, %u, %u\n",
                            ntohl(item->type), ntohl(item->lower),
                            ntohl(item->upper));
                        publ = tipc_nametbl_remove_publ(ntohl(item->type),
                                                        ntohl(item->lower),
                                                        msg_orignode(msg),
                                                        ntohl(item->ref),
                                                        ntohl(item->key));

                        if (publ) {
                                tipc_nodesub_unsubscribe(&publ->subscr);
                                kfree(publ);
                        } else {
                                err("Unable to remove publication by node 0x%x\n"
                                    "(type=%u, lower=%u, ref=%u, key=%u)\n",
                                    msg_orignode(msg),
                                    ntohl(item->type), ntohl(item->lower),
                                    ntohl(item->ref), ntohl(item->key));
                        }
                } else {
                        warn("Unrecognized name table message received\n");
                }
                item++;
        }
        write_unlock_bh(&tipc_nametbl_lock);
        buf_discard(buf);
}

/**
 * tipc_named_reinit - re-initialize local publication list
 *
 * This routine is called whenever TIPC networking is (re)enabled.
 * All existing publications by this node that have "cluster" or "zone" scope
 * are updated to reflect the node's current network address.
 * (If the node's address is unchanged, the update loop terminates immediately.)
 */

void tipc_named_reinit(void)
{
        struct publication *publ;

        write_lock_bh(&tipc_nametbl_lock);
        list_for_each_entry(publ, &publ_root, local_list) {
                if (publ->node == tipc_own_addr)
                        break;
                publ->node = tipc_own_addr;
        }
        write_unlock_bh(&tipc_nametbl_lock);
}