/*
 * net/tipc/name_distr.c: TIPC name distribution code
 *
 * Copyright (c) 2000-2006, 2014, Ericsson AB
 * Copyright (c) 2005, 2010-2011, 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 "link.h"
#include "name_distr.h"

int sysctl_tipc_named_timeout __read_mostly = 2000;

/**
 * struct tipc_dist_queue - queue holding deferred name table updates
 */
static struct list_head tipc_dist_queue = LIST_HEAD_INIT(tipc_dist_queue);

struct distr_queue_item {
        struct distr_item i;
        u32 dtype;
        u32 node;
        unsigned long expires;
        struct list_head next;
};

/**
 * 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);
}

/**
 * named_prepare_buf - allocate & initialize a publication message
 */
static struct sk_buff *named_prepare_buf(struct net *net, u32 type, u32 size,
                                         u32 dest)
{
        struct tipc_net *tn = net_generic(net, tipc_net_id);
        struct sk_buff *buf = tipc_buf_acquire(INT_H_SIZE + size);
        struct tipc_msg *msg;

        if (buf != NULL) {
                msg = buf_msg(buf);
                tipc_msg_init(tn->own_addr, msg, NAME_DISTRIBUTOR, type,
                              INT_H_SIZE, dest);
                msg_set_size(msg, INT_H_SIZE + size);
        }
        return buf;
}

void named_cluster_distribute(struct net *net, struct sk_buff *skb)
{
        struct tipc_net *tn = net_generic(net, tipc_net_id);
        struct sk_buff *oskb;
        struct tipc_node *node;
        u32 dnode;

        rcu_read_lock();
        list_for_each_entry_rcu(node, &tn->node_list, list) {
                dnode = node->addr;
                if (in_own_node(net, dnode))
                        continue;
                if (!tipc_node_is_up(node))
                        continue;
                oskb = pskb_copy(skb, GFP_ATOMIC);
                if (!oskb)
                        break;
                msg_set_destnode(buf_msg(oskb), dnode);
                tipc_node_xmit_skb(net, oskb, dnode, 0);
        }
        rcu_read_unlock();

        kfree_skb(skb);
}

/**
 * tipc_named_publish - tell other nodes about a new publication by this node
 */
struct sk_buff *tipc_named_publish(struct net *net, struct publication *publ)
{
        struct tipc_net *tn = net_generic(net, tipc_net_id);
        struct sk_buff *buf;
        struct distr_item *item;

        list_add_tail_rcu(&publ->local_list,
                          &tn->nametbl->publ_list[publ->scope]);

        if (publ->scope == TIPC_NODE_SCOPE)
                return NULL;

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

        item = (struct distr_item *)msg_data(buf_msg(buf));
        publ_to_item(item, publ);
        return buf;
}

/**
 * tipc_named_withdraw - tell other nodes about a withdrawn publication by this node
 */
struct sk_buff *tipc_named_withdraw(struct net *net, struct publication *publ)
{
        struct sk_buff *buf;
        struct distr_item *item;

        list_del(&publ->local_list);

        if (publ->scope == TIPC_NODE_SCOPE)
                return NULL;

        buf = named_prepare_buf(net, WITHDRAWAL, ITEM_SIZE, 0);
        if (!buf) {
                pr_warn("Withdrawal distribution failure\n");
                return NULL;
        }

        item = (struct distr_item *)msg_data(buf_msg(buf));
        publ_to_item(item, publ);
        return buf;
}

/**
 * named_distribute - prepare name info for bulk distribution to another node
 * @list: list of messages (buffers) to be returned from this function
 * @dnode: node to be updated
 * @pls: linked list of publication items to be packed into buffer chain
 */
static void named_distribute(struct net *net, struct sk_buff_head *list,
                             u32 dnode, struct list_head *pls)
{
        struct publication *publ;
        struct sk_buff *skb = NULL;
        struct distr_item *item = NULL;
        uint msg_dsz = (tipc_node_get_mtu(net, dnode, 0) / ITEM_SIZE) *
                        ITEM_SIZE;
        uint msg_rem = msg_dsz;

        list_for_each_entry(publ, pls, local_list) {
                /* Prepare next buffer: */
                if (!skb) {
                        skb = named_prepare_buf(net, PUBLICATION, msg_rem,
                                                dnode);
                        if (!skb) {
                                pr_warn("Bulk publication failure\n");
                                return;
                        }
                        item = (struct distr_item *)msg_data(buf_msg(skb));
                }

                /* Pack publication into message: */
                publ_to_item(item, publ);
                item++;
                msg_rem -= ITEM_SIZE;

                /* Append full buffer to list: */
                if (!msg_rem) {
                        __skb_queue_tail(list, skb);
                        skb = NULL;
                        msg_rem = msg_dsz;
                }
        }
        if (skb) {
                msg_set_size(buf_msg(skb), INT_H_SIZE + (msg_dsz - msg_rem));
                skb_trim(skb, INT_H_SIZE + (msg_dsz - msg_rem));
                __skb_queue_tail(list, skb);
        }
}

/**
 * tipc_named_node_up - tell specified node about all publications by this node
 */
void tipc_named_node_up(struct net *net, u32 dnode)
{
        struct tipc_net *tn = net_generic(net, tipc_net_id);
        struct sk_buff_head head;

        __skb_queue_head_init(&head);

        rcu_read_lock();
        named_distribute(net, &head, dnode,
                         &tn->nametbl->publ_list[TIPC_CLUSTER_SCOPE]);
        named_distribute(net, &head, dnode,
                         &tn->nametbl->publ_list[TIPC_ZONE_SCOPE]);
        rcu_read_unlock();

        tipc_node_xmit(net, &head, dnode, 0);
}

static void tipc_publ_subscribe(struct net *net, struct publication *publ,
                                u32 addr)
{
        struct tipc_node *node;

        if (in_own_node(net, addr))
                return;

        node = tipc_node_find(net, addr);
        if (!node) {
                pr_warn("Node subscription rejected, unknown node 0x%x\n",
                        addr);
                return;
        }

        tipc_node_lock(node);
        list_add_tail(&publ->nodesub_list, &node->publ_list);
        tipc_node_unlock(node);
        tipc_node_put(node);
}

static void tipc_publ_unsubscribe(struct net *net, struct publication *publ,
                                  u32 addr)
{
        struct tipc_node *node;

        node = tipc_node_find(net, addr);
        if (!node)
                return;

        tipc_node_lock(node);
        list_del_init(&publ->nodesub_list);
        tipc_node_unlock(node);
        tipc_node_put(node);
}

/**
 * tipc_publ_purge - 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.
 */
static void tipc_publ_purge(struct net *net, struct publication *publ, u32 addr)
{
        struct tipc_net *tn = net_generic(net, tipc_net_id);
        struct publication *p;

        spin_lock_bh(&tn->nametbl_lock);
        p = tipc_nametbl_remove_publ(net, publ->type, publ->lower,
                                     publ->node, publ->ref, publ->key);
        if (p)
                tipc_publ_unsubscribe(net, p, addr);
        spin_unlock_bh(&tn->nametbl_lock);

        if (p != publ) {
                pr_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);
        }

        kfree_rcu(p, rcu);
}

void tipc_publ_notify(struct net *net, struct list_head *nsub_list, u32 addr)
{
        struct publication *publ, *tmp;

        list_for_each_entry_safe(publ, tmp, nsub_list, nodesub_list)
                tipc_publ_purge(net, publ, addr);
}

/**
 * tipc_update_nametbl - try to process a nametable update and notify
 *                       subscribers
 *
 * tipc_nametbl_lock must be held.
 * Returns the publication item if successful, otherwise NULL.
 */
static bool tipc_update_nametbl(struct net *net, struct distr_item *i,
                                u32 node, u32 dtype)
{
        struct publication *publ = NULL;

        if (dtype == PUBLICATION) {
                publ = tipc_nametbl_insert_publ(net, ntohl(i->type),
                                                ntohl(i->lower),
                                                ntohl(i->upper),
                                                TIPC_CLUSTER_SCOPE, node,
                                                ntohl(i->ref), ntohl(i->key));
                if (publ) {
                        tipc_publ_subscribe(net, publ, node);
                        return true;
                }
        } else if (dtype == WITHDRAWAL) {
                publ = tipc_nametbl_remove_publ(net, ntohl(i->type),
                                                ntohl(i->lower),
                                                node, ntohl(i->ref),
                                                ntohl(i->key));
                if (publ) {
                        tipc_publ_unsubscribe(net, publ, node);
                        kfree_rcu(publ, rcu);
                        return true;
                }
        } else {
                pr_warn("Unrecognized name table message received\n");
        }
        return false;
}

/**
 * tipc_named_add_backlog - add a failed name table update to the backlog
 *
 */
static void tipc_named_add_backlog(struct distr_item *i, u32 type, u32 node)
{
        struct distr_queue_item *e;
        unsigned long now = get_jiffies_64();

        e = kzalloc(sizeof(*e), GFP_ATOMIC);
        if (!e)
                return;
        e->dtype = type;
        e->node = node;
        e->expires = now + msecs_to_jiffies(sysctl_tipc_named_timeout);
        memcpy(e, i, sizeof(*i));
        list_add_tail(&e->next, &tipc_dist_queue);
}

/**
 * tipc_named_process_backlog - try to process any pending name table updates
 * from the network.
 */
void tipc_named_process_backlog(struct net *net)
{
        struct distr_queue_item *e, *tmp;
        char addr[16];
        unsigned long now = get_jiffies_64();

        list_for_each_entry_safe(e, tmp, &tipc_dist_queue, next) {
                if (time_after(e->expires, now)) {
                        if (!tipc_update_nametbl(net, &e->i, e->node, e->dtype))
                                continue;
                } else {
                        tipc_addr_string_fill(addr, e->node);
                        pr_warn_ratelimited("Dropping name table update (%d) of {%u, %u, %u} from %s key=%u\n",
                                            e->dtype, ntohl(e->i.type),
                                            ntohl(e->i.lower),
                                            ntohl(e->i.upper),
                                            addr, ntohl(e->i.key));
                }
                list_del(&e->next);
                kfree(e);
        }
}

/**
 * tipc_named_rcv - process name table update messages sent by another node
 */
void tipc_named_rcv(struct net *net, struct sk_buff_head *inputq)
{
        struct tipc_net *tn = net_generic(net, tipc_net_id);
        struct tipc_msg *msg;
        struct distr_item *item;
        uint count;
        u32 node;
        struct sk_buff *skb;
        int mtype;

        spin_lock_bh(&tn->nametbl_lock);
        for (skb = skb_dequeue(inputq); skb; skb = skb_dequeue(inputq)) {
                msg = buf_msg(skb);
                mtype = msg_type(msg);
                item = (struct distr_item *)msg_data(msg);
                count = msg_data_sz(msg) / ITEM_SIZE;
                node = msg_orignode(msg);
                while (count--) {
                        if (!tipc_update_nametbl(net, item, node, mtype))
                                tipc_named_add_backlog(item, mtype, node);
                        item++;
                }
                kfree_skb(skb);
                tipc_named_process_backlog(net);
        }
        spin_unlock_bh(&tn->nametbl_lock);
}

/**
 * tipc_named_reinit - re-initialize local publications
 *
 * This routine is called whenever TIPC networking is enabled.
 * All name table entries published by this node are updated to reflect
 * the node's new network address.
 */
void tipc_named_reinit(struct net *net)
{
        struct tipc_net *tn = net_generic(net, tipc_net_id);
        struct publication *publ;
        int scope;

        spin_lock_bh(&tn->nametbl_lock);

        for (scope = TIPC_ZONE_SCOPE; scope <= TIPC_NODE_SCOPE; scope++)
                list_for_each_entry_rcu(publ, &tn->nametbl->publ_list[scope],
                                        local_list)
                        publ->node = tn->own_addr;

        spin_unlock_bh(&tn->nametbl_lock);
}