/*
   * net/tipc/name_table.c: TIPC name table code

   *

   * Copyright (c) 2000-2006, Ericsson AB

   * Copyright (c) 2004-2008, 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 "config.h"

  #include "name_table.h"
  #include "name_distr.h"

  #include "subscr.h"
  #include "port.h"

  static int tipc_nametbl_size = 1024;		/* must be a power of 2 */

  
  /**

   * struct name_info - name sequence publication info

   * @node_list: circular list of publications made by own node
   * @cluster_list: circular list of publications made by own cluster
   * @zone_list: circular list of publications made by own zone
   * @node_list_size: number of entries in "node_list"
   * @cluster_list_size: number of entries in "cluster_list"
   * @zone_list_size: number of entries in "zone_list"
   *
   * Note: The zone list always contains at least one entry, since all
   *       publications of the associated name sequence belong to it.
   *       (The cluster and node lists may be empty.)

   */

  struct name_info {

  	struct list_head node_list;
  	struct list_head cluster_list;
  	struct list_head zone_list;

  	u32 node_list_size;
  	u32 cluster_list_size;
  	u32 zone_list_size;

  };

  /**

   * struct sub_seq - container for all published instances of a name sequence
   * @lower: name sequence lower bound
   * @upper: name sequence upper bound
   * @info: pointer to name sequence publication info
   */
  
  struct sub_seq {
  	u32 lower;
  	u32 upper;
  	struct name_info *info;
  };
  
  /**

   * struct name_seq - container for all published instances of a name type
   * @type: 32 bit 'type' value for name sequence
   * @sseq: pointer to dynamically-sized array of sub-sequences of this 'type';
   *        sub-sequences are sorted in ascending order
   * @alloc: number of sub-sequences currently in array

   * @first_free: array index of first unused sub-sequence entry

   * @ns_list: links to adjacent name sequences in hash chain
   * @subscriptions: list of subscriptions for this 'type'

   * @lock: spinlock controlling access to publication lists of all sub-sequences

   */
  
  struct name_seq {
  	u32 type;
  	struct sub_seq *sseqs;
  	u32 alloc;
  	u32 first_free;
  	struct hlist_node ns_list;
  	struct list_head subscriptions;
  	spinlock_t lock;
  };
  
  /**
   * struct name_table - table containing all existing port name publications

   * @types: pointer to fixed-sized array of name sequence lists,

   *         accessed via hashing on 'type'; name sequence lists are *not* sorted
   * @local_publ_count: number of publications issued by this node
   */
  
  struct name_table {
  	struct hlist_head *types;
  	u32 local_publ_count;
  };

  static struct name_table table;

  static atomic_t rsv_publ_ok = ATOMIC_INIT(0);

  DEFINE_RWLOCK(tipc_nametbl_lock);

  static int hash(int x)

  {

  	return x & (tipc_nametbl_size - 1);

  }
  
  /**
   * publ_create - create a publication structure
   */

  static struct publication *publ_create(u32 type, u32 lower, u32 upper,
  				       u32 scope, u32 node, u32 port_ref,

  				       u32 key)
  {

  	struct publication *publ = kzalloc(sizeof(*publ), GFP_ATOMIC);

  	if (publ == NULL) {

  		warn("Publication creation failure, no memory
  ");

  		return NULL;

  	}

  	publ->type = type;
  	publ->lower = lower;
  	publ->upper = upper;
  	publ->scope = scope;
  	publ->node = node;
  	publ->ref = port_ref;
  	publ->key = key;
  	INIT_LIST_HEAD(&publ->local_list);
  	INIT_LIST_HEAD(&publ->pport_list);
  	INIT_LIST_HEAD(&publ->subscr.nodesub_list);
  	return publ;
  }
  
  /**

   * tipc_subseq_alloc - allocate a specified number of sub-sequence structures

   */

  static struct sub_seq *tipc_subseq_alloc(u32 cnt)

  {

  	struct sub_seq *sseq = kcalloc(cnt, sizeof(struct sub_seq), GFP_ATOMIC);

  	return sseq;
  }
  
  /**

   * tipc_nameseq_create - create a name sequence structure for the specified 'type'

   *

   * Allocates a single sub-sequence structure and sets it to all 0's.
   */

  static struct name_seq *tipc_nameseq_create(u32 type, struct hlist_head *seq_head)

  {

  	struct name_seq *nseq = kzalloc(sizeof(*nseq), GFP_ATOMIC);

  	struct sub_seq *sseq = tipc_subseq_alloc(1);

  
  	if (!nseq || !sseq) {

  		warn("Name sequence creation failed, no memory
  ");

  		kfree(nseq);
  		kfree(sseq);

  		return NULL;

  	}

  	spin_lock_init(&nseq->lock);

  	nseq->type = type;
  	nseq->sseqs = sseq;

  	nseq->alloc = 1;
  	INIT_HLIST_NODE(&nseq->ns_list);
  	INIT_LIST_HEAD(&nseq->subscriptions);
  	hlist_add_head(&nseq->ns_list, seq_head);
  	return nseq;
  }
  
  /**
   * nameseq_find_subseq - find sub-sequence (if any) matching a name instance

   *

   * Very time-critical, so binary searches through sub-sequence array.
   */

  static struct sub_seq *nameseq_find_subseq(struct name_seq *nseq,
  					   u32 instance)

  {
  	struct sub_seq *sseqs = nseq->sseqs;
  	int low = 0;
  	int high = nseq->first_free - 1;
  	int mid;
  
  	while (low <= high) {
  		mid = (low + high) / 2;
  		if (instance < sseqs[mid].lower)
  			high = mid - 1;
  		else if (instance > sseqs[mid].upper)
  			low = mid + 1;
  		else
  			return &sseqs[mid];
  	}

  	return NULL;

  }
  
  /**
   * nameseq_locate_subseq - determine position of name instance in sub-sequence

   *

   * Returns index in sub-sequence array of the entry that contains the specified
   * instance value; if no entry contains that value, returns the position
   * where a new entry for it would be inserted in the array.
   *
   * Note: Similar to binary search code for locating a sub-sequence.
   */
  
  static u32 nameseq_locate_subseq(struct name_seq *nseq, u32 instance)
  {
  	struct sub_seq *sseqs = nseq->sseqs;
  	int low = 0;
  	int high = nseq->first_free - 1;
  	int mid;
  
  	while (low <= high) {
  		mid = (low + high) / 2;
  		if (instance < sseqs[mid].lower)
  			high = mid - 1;
  		else if (instance > sseqs[mid].upper)
  			low = mid + 1;
  		else
  			return mid;
  	}
  	return low;
  }
  
  /**

   * tipc_nameseq_insert_publ -

   */

  static struct publication *tipc_nameseq_insert_publ(struct name_seq *nseq,
  						    u32 type, u32 lower, u32 upper,
  						    u32 scope, u32 node, u32 port, u32 key)

  {

  	struct tipc_subscription *s;
  	struct tipc_subscription *st;

  	struct publication *publ;
  	struct sub_seq *sseq;

  	struct name_info *info;

  	int created_subseq = 0;

  	sseq = nameseq_find_subseq(nseq, lower);

  	if (sseq) {
  
  		/* Lower end overlaps existing entry => need an exact match */
  
  		if ((sseq->lower != lower) || (sseq->upper != upper)) {

  			warn("Cannot publish {%u,%u,%u}, overlap error
  ",
  			     type, lower, upper);

  			return NULL;

  		}

  
  		info = sseq->info;

  	} else {
  		u32 inspos;
  		struct sub_seq *freesseq;
  
  		/* Find where lower end should be inserted */
  
  		inspos = nameseq_locate_subseq(nseq, lower);
  
  		/* Fail if upper end overlaps into an existing entry */
  
  		if ((inspos < nseq->first_free) &&
  		    (upper >= nseq->sseqs[inspos].lower)) {

  			warn("Cannot publish {%u,%u,%u}, overlap error
  ",
  			     type, lower, upper);

  			return NULL;

  		}
  
  		/* Ensure there is space for new sub-sequence */
  
  		if (nseq->first_free == nseq->alloc) {

  			struct sub_seq *sseqs = tipc_subseq_alloc(nseq->alloc * 2);
  
  			if (!sseqs) {

  				warn("Cannot publish {%u,%u,%u}, no memory
  ",
  				     type, lower, upper);

  				return NULL;

  			}

  			memcpy(sseqs, nseq->sseqs,
  			       nseq->alloc * sizeof(struct sub_seq));
  			kfree(nseq->sseqs);
  			nseq->sseqs = sseqs;
  			nseq->alloc *= 2;

  		}

  		info = kzalloc(sizeof(*info), GFP_ATOMIC);
  		if (!info) {
  			warn("Cannot publish {%u,%u,%u}, no memory
  ",
  			     type, lower, upper);
  			return NULL;
  		}

  		INIT_LIST_HEAD(&info->node_list);
  		INIT_LIST_HEAD(&info->cluster_list);
  		INIT_LIST_HEAD(&info->zone_list);

  		/* Insert new sub-sequence */

  		sseq = &nseq->sseqs[inspos];
  		freesseq = &nseq->sseqs[nseq->first_free];

  		memmove(sseq + 1, sseq, (freesseq - sseq) * sizeof(*sseq));
  		memset(sseq, 0, sizeof(*sseq));

  		nseq->first_free++;
  		sseq->lower = lower;
  		sseq->upper = upper;

  		sseq->info = info;

  		created_subseq = 1;
  	}

  
  	/* Insert a publication: */
  
  	publ = publ_create(type, lower, upper, scope, node, port, key);
  	if (!publ)

  		return NULL;

  	list_add(&publ->zone_list, &info->zone_list);

  	info->zone_list_size++;

  
  	if (in_own_cluster(node)) {

  		list_add(&publ->cluster_list, &info->cluster_list);

  		info->cluster_list_size++;

  	}
  
  	if (node == tipc_own_addr) {

  		list_add(&publ->node_list, &info->node_list);

  		info->node_list_size++;

  	}

  	/*
  	 * Any subscriptions waiting for notification?

  	 */
  	list_for_each_entry_safe(s, st, &nseq->subscriptions, nameseq_list) {

  		tipc_subscr_report_overlap(s,
  					   publ->lower,
  					   publ->upper,
  					   TIPC_PUBLISHED,

  					   publ->ref,

  					   publ->node,
  					   created_subseq);

  	}
  	return publ;
  }
  
  /**

   * tipc_nameseq_remove_publ -

   *

   * NOTE: There may be cases where TIPC is asked to remove a publication
   * that is not in the name table.  For example, if another node issues a
   * publication for a name sequence that overlaps an existing name sequence
   * the publication will not be recorded, which means the publication won't
   * be found when the name sequence is later withdrawn by that node.
   * A failed withdraw request simply returns a failure indication and lets the
   * caller issue any error or warning messages associated with such a problem.

   */

  static struct publication *tipc_nameseq_remove_publ(struct name_seq *nseq, u32 inst,
  						    u32 node, u32 ref, u32 key)

  {
  	struct publication *publ;

  	struct sub_seq *sseq = nameseq_find_subseq(nseq, inst);

  	struct name_info *info;

  	struct sub_seq *free;

  	struct tipc_subscription *s, *st;

  	int removed_subseq = 0;

  	if (!sseq)

  		return NULL;

  	info = sseq->info;

  	/* Locate publication, if it exists */

  	list_for_each_entry(publ, &info->zone_list, zone_list) {
  		if ((publ->key == key) && (publ->ref == ref) &&
  		    (!publ->node || (publ->node == node)))
  			goto found;
  	}
  	return NULL;

  found:
  	/* Remove publication from zone scope list */

  	list_del(&publ->zone_list);

  	info->zone_list_size--;

  	/* Remove publication from cluster scope list, if present */

  	if (in_own_cluster(node)) {

  		list_del(&publ->cluster_list);

  		info->cluster_list_size--;

  	}

  
  	/* Remove publication from node scope list, if present */

  
  	if (node == tipc_own_addr) {

  		list_del(&publ->node_list);

  		info->node_list_size--;

  	}

  	/* Contract subseq list if no more publications for that subseq */

  	if (list_empty(&info->zone_list)) {

  		kfree(info);

  		free = &nseq->sseqs[nseq->first_free--];

  		memmove(sseq, sseq + 1, (free - (sseq + 1)) * sizeof(*sseq));

  		removed_subseq = 1;
  	}

  	/* Notify any waiting subscriptions */

  	list_for_each_entry_safe(s, st, &nseq->subscriptions, nameseq_list) {

  		tipc_subscr_report_overlap(s,
  					   publ->lower,
  					   publ->upper,

  					   TIPC_WITHDRAWN,
  					   publ->ref,

  					   publ->node,
  					   removed_subseq);

  	}

  	return publ;
  }
  
  /**

   * tipc_nameseq_subscribe: attach a subscription, and issue

   * the prescribed number of events if there is any sub-
   * sequence overlapping with the requested sequence
   */

  static void tipc_nameseq_subscribe(struct name_seq *nseq,
  					struct tipc_subscription *s)

  {
  	struct sub_seq *sseq = nseq->sseqs;
  
  	list_add(&s->nameseq_list, &nseq->subscriptions);
  
  	if (!sseq)
  		return;
  
  	while (sseq != &nseq->sseqs[nseq->first_free]) {

  		if (tipc_subscr_overlap(s, sseq->lower, sseq->upper)) {
  			struct publication *crs;
  			struct name_info *info = sseq->info;

  			int must_report = 1;

  			list_for_each_entry(crs, &info->zone_list, zone_list) {

  				tipc_subscr_report_overlap(s,
  							   sseq->lower,

  							   sseq->upper,
  							   TIPC_PUBLISHED,
  							   crs->ref,
  							   crs->node,
  							   must_report);

  				must_report = 0;

  			}

  		}
  		sseq++;
  	}
  }
  
  static struct name_seq *nametbl_find_seq(u32 type)
  {
  	struct hlist_head *seq_head;
  	struct hlist_node *seq_node;
  	struct name_seq *ns;

  	seq_head = &table.types[hash(type)];
  	hlist_for_each_entry(ns, seq_node, seq_head, ns_list) {

  		if (ns->type == type)

  			return ns;

  	}

  	return NULL;

  };

  struct publication *tipc_nametbl_insert_publ(u32 type, u32 lower, u32 upper,
  					     u32 scope, u32 node, u32 port, u32 key)

  {
  	struct name_seq *seq = nametbl_find_seq(type);

  	if (lower > upper) {

  		warn("Failed to publish illegal {%u,%u,%u}
  ",

  		     type, lower, upper);

  		return NULL;

  	}

  	if (!seq)

  		seq = tipc_nameseq_create(type, &table.types[hash(type)]);

  	if (!seq)

  		return NULL;

  	return tipc_nameseq_insert_publ(seq, type, lower, upper,
  					scope, node, port, key);

  }

  struct publication *tipc_nametbl_remove_publ(u32 type, u32 lower,

  					     u32 node, u32 ref, u32 key)

  {
  	struct publication *publ;
  	struct name_seq *seq = nametbl_find_seq(type);
  
  	if (!seq)

  		return NULL;

  	publ = tipc_nameseq_remove_publ(seq, lower, node, ref, key);

  
  	if (!seq->first_free && list_empty(&seq->subscriptions)) {
  		hlist_del_init(&seq->ns_list);
  		kfree(seq->sseqs);
  		kfree(seq);
  	}
  	return publ;
  }
  
  /*

   * tipc_nametbl_translate - translate name to port id

   *
   * Note: on entry 'destnode' is the search domain used during translation;
   *       on exit it passes back the node address of the matching port (if any)
   */

  u32 tipc_nametbl_translate(u32 type, u32 instance, u32 *destnode)

  {
  	struct sub_seq *sseq;

  	struct name_info *info;

  	struct publication *publ;

  	struct name_seq *seq;

  	u32 ref = 0;

  	if (!tipc_in_scope(*destnode, tipc_own_addr))

  		return 0;

  	read_lock_bh(&tipc_nametbl_lock);

  	seq = nametbl_find_seq(type);
  	if (unlikely(!seq))
  		goto not_found;
  	sseq = nameseq_find_subseq(seq, instance);
  	if (unlikely(!sseq))
  		goto not_found;
  	spin_lock_bh(&seq->lock);

  	info = sseq->info;

  
  	/* Closest-First Algorithm: */
  	if (likely(!*destnode)) {

  		if (!list_empty(&info->node_list)) {
  			publ = list_first_entry(&info->node_list,
  						struct publication,
  						node_list);
  			list_move_tail(&publ->node_list,
  				       &info->node_list);
  		} else if (!list_empty(&info->cluster_list)) {
  			publ = list_first_entry(&info->cluster_list,
  						struct publication,
  						cluster_list);
  			list_move_tail(&publ->cluster_list,
  				       &info->cluster_list);

  		} else {

  			publ = list_first_entry(&info->zone_list,
  						struct publication,
  						zone_list);
  			list_move_tail(&publ->zone_list,
  				       &info->zone_list);

  		}

  	}
  
  	/* Round-Robin Algorithm: */
  	else if (*destnode == tipc_own_addr) {

  		if (list_empty(&info->node_list))
  			goto no_match;
  		publ = list_first_entry(&info->node_list, struct publication,
  					node_list);
  		list_move_tail(&publ->node_list, &info->node_list);

  	} else if (in_own_cluster(*destnode)) {

  		if (list_empty(&info->cluster_list))
  			goto no_match;
  		publ = list_first_entry(&info->cluster_list, struct publication,
  					cluster_list);
  		list_move_tail(&publ->cluster_list, &info->cluster_list);

  	} else {

  		publ = list_first_entry(&info->zone_list, struct publication,
  					zone_list);
  		list_move_tail(&publ->zone_list, &info->zone_list);

  	}

  
  	ref = publ->ref;
  	*destnode = publ->node;
  no_match:

  	spin_unlock_bh(&seq->lock);
  not_found:

  	read_unlock_bh(&tipc_nametbl_lock);

  	return ref;

  }
  
  /**

   * tipc_nametbl_mc_translate - find multicast destinations

   *

   * Creates list of all local ports that overlap the given multicast address;
   * also determines if any off-node ports overlap.
   *
   * Note: Publications with a scope narrower than 'limit' are ignored.
   * (i.e. local node-scope publications mustn't receive messages arriving
   * from another node, even if the multcast link brought it here)

   *

   * Returns non-zero if any off-node ports overlap
   */

  int tipc_nametbl_mc_translate(u32 type, u32 lower, u32 upper, u32 limit,

  			      struct tipc_port_list *dports)

  {
  	struct name_seq *seq;
  	struct sub_seq *sseq;
  	struct sub_seq *sseq_stop;

  	struct name_info *info;

  	int res = 0;

  	read_lock_bh(&tipc_nametbl_lock);

  	seq = nametbl_find_seq(type);
  	if (!seq)
  		goto exit;
  
  	spin_lock_bh(&seq->lock);
  
  	sseq = seq->sseqs + nameseq_locate_subseq(seq, lower);
  	sseq_stop = seq->sseqs + seq->first_free;
  	for (; sseq != sseq_stop; sseq++) {
  		struct publication *publ;
  
  		if (sseq->lower > upper)
  			break;

  		info = sseq->info;

  		list_for_each_entry(publ, &info->node_list, node_list) {
  			if (publ->scope <= limit)
  				tipc_port_list_add(dports, publ->ref);

  		}

  		if (info->cluster_list_size != info->node_list_size)

  			res = 1;

  	}
  
  	spin_unlock_bh(&seq->lock);
  exit:

  	read_unlock_bh(&tipc_nametbl_lock);

  	return res;
  }
  
  /**

   * tipc_nametbl_publish_rsv - publish port name using a reserved name type

   */

  int tipc_nametbl_publish_rsv(u32 ref, unsigned int scope,

  			struct tipc_name_seq const *seq)
  {
  	int res;
  
  	atomic_inc(&rsv_publ_ok);
  	res = tipc_publish(ref, scope, seq);
  	atomic_dec(&rsv_publ_ok);
  	return res;
  }
  
  /**

   * tipc_nametbl_publish - add name publication to network name tables

   */

  struct publication *tipc_nametbl_publish(u32 type, u32 lower, u32 upper,

  				    u32 scope, u32 port_ref, u32 key)
  {
  	struct publication *publ;
  
  	if (table.local_publ_count >= tipc_max_publications) {

  		warn("Publication failed, local publication limit reached (%u)
  ",

  		     tipc_max_publications);

  		return NULL;

  	}
  	if ((type < TIPC_RESERVED_TYPES) && !atomic_read(&rsv_publ_ok)) {

  		warn("Publication failed, reserved name {%u,%u,%u}
  ",

  		     type, lower, upper);

  		return NULL;

  	}

  	write_lock_bh(&tipc_nametbl_lock);

  	table.local_publ_count++;

  	publ = tipc_nametbl_insert_publ(type, lower, upper, scope,

  				   tipc_own_addr, port_ref, key);

  	if (publ && (scope != TIPC_NODE_SCOPE))

  		tipc_named_publish(publ);

  	write_unlock_bh(&tipc_nametbl_lock);

  	return publ;
  }
  
  /**

   * tipc_nametbl_withdraw - withdraw name publication from network name tables

   */

  int tipc_nametbl_withdraw(u32 type, u32 lower, u32 ref, u32 key)

  {
  	struct publication *publ;

  	write_lock_bh(&tipc_nametbl_lock);
  	publ = tipc_nametbl_remove_publ(type, lower, tipc_own_addr, ref, key);

  	if (likely(publ)) {

  		table.local_publ_count--;
  		if (publ->scope != TIPC_NODE_SCOPE)

  			tipc_named_withdraw(publ);
  		write_unlock_bh(&tipc_nametbl_lock);

  		list_del_init(&publ->pport_list);
  		kfree(publ);
  		return 1;
  	}

  	write_unlock_bh(&tipc_nametbl_lock);

  	err("Unable to remove local publication
  "
  	    "(type=%u, lower=%u, ref=%u, key=%u)
  ",
  	    type, lower, ref, key);

  	return 0;
  }
  
  /**

   * tipc_nametbl_subscribe - add a subscription object to the name table

   */

  void tipc_nametbl_subscribe(struct tipc_subscription *s)

  {
  	u32 type = s->seq.type;
  	struct name_seq *seq;

  	write_lock_bh(&tipc_nametbl_lock);

  	seq = nametbl_find_seq(type);

  	if (!seq)

  		seq = tipc_nameseq_create(type, &table.types[hash(type)]);

  	if (seq) {

  		spin_lock_bh(&seq->lock);

  		tipc_nameseq_subscribe(seq, s);
  		spin_unlock_bh(&seq->lock);
  	} else {

  		warn("Failed to create subscription for {%u,%u,%u}
  ",
  		     s->seq.type, s->seq.lower, s->seq.upper);

  	}
  	write_unlock_bh(&tipc_nametbl_lock);

  }
  
  /**

   * tipc_nametbl_unsubscribe - remove a subscription object from name table

   */

  void tipc_nametbl_unsubscribe(struct tipc_subscription *s)

  {
  	struct name_seq *seq;

  	write_lock_bh(&tipc_nametbl_lock);
  	seq = nametbl_find_seq(s->seq.type);

  	if (seq != NULL) {

  		spin_lock_bh(&seq->lock);
  		list_del_init(&s->nameseq_list);
  		spin_unlock_bh(&seq->lock);
  		if ((seq->first_free == 0) && list_empty(&seq->subscriptions)) {
  			hlist_del_init(&seq->ns_list);
  			kfree(seq->sseqs);
  			kfree(seq);
  		}
  	}
  	write_unlock_bh(&tipc_nametbl_lock);

  }
  
  
  /**
   * subseq_list: print specified sub-sequence contents into the given buffer
   */
  
  static void subseq_list(struct sub_seq *sseq, struct print_buf *buf, u32 depth,
  			u32 index)
  {
  	char portIdStr[27];

  	const char *scope_str[] = {"", " zone", " cluster", " node"};

  	struct publication *publ;
  	struct name_info *info;

  
  	tipc_printf(buf, "%-10u %-10u ", sseq->lower, sseq->upper);

  	if (depth == 2) {

  		tipc_printf(buf, "
  ");
  		return;
  	}

  	info = sseq->info;
  
  	list_for_each_entry(publ, &info->zone_list, zone_list) {

  		sprintf(portIdStr, "<%u.%u.%u:%u>",

  			 tipc_zone(publ->node), tipc_cluster(publ->node),
  			 tipc_node(publ->node), publ->ref);
  		tipc_printf(buf, "%-26s ", portIdStr);
  		if (depth > 3) {

  			tipc_printf(buf, "%-10u %s", publ->key,
  				    scope_str[publ->scope]);

  		}

  		if (!list_is_last(&publ->zone_list, &info->zone_list))
  			tipc_printf(buf, "
  %33s", " ");
  	};

  
  	tipc_printf(buf, "
  ");
  }
  
  /**
   * nameseq_list: print specified name sequence contents into the given buffer
   */
  
  static void nameseq_list(struct name_seq *seq, struct print_buf *buf, u32 depth,
  			 u32 type, u32 lowbound, u32 upbound, u32 index)
  {
  	struct sub_seq *sseq;
  	char typearea[11];

  	if (seq->first_free == 0)
  		return;

  	sprintf(typearea, "%-10u", seq->type);
  
  	if (depth == 1) {
  		tipc_printf(buf, "%s
  ", typearea);
  		return;
  	}
  
  	for (sseq = seq->sseqs; sseq != &seq->sseqs[seq->first_free]; sseq++) {
  		if ((lowbound <= sseq->upper) && (upbound >= sseq->lower)) {
  			tipc_printf(buf, "%s ", typearea);

  			spin_lock_bh(&seq->lock);

  			subseq_list(sseq, buf, depth, index);

  			spin_unlock_bh(&seq->lock);

  			sprintf(typearea, "%10s", " ");
  		}
  	}
  }
  
  /**
   * nametbl_header - print name table header into the given buffer
   */
  
  static void nametbl_header(struct print_buf *buf, u32 depth)
  {

  	const char *header[] = {
  		"Type       ",
  		"Lower      Upper      ",
  		"Port Identity              ",
  		"Publication Scope"
  	};
  
  	int i;
  
  	if (depth > 4)
  		depth = 4;
  	for (i = 0; i < depth; i++)
  		tipc_printf(buf, header[i]);

  	tipc_printf(buf, "
  ");
  }
  
  /**
   * nametbl_list - print specified name table contents into the given buffer
   */

  static void nametbl_list(struct print_buf *buf, u32 depth_info,

  			 u32 type, u32 lowbound, u32 upbound)
  {
  	struct hlist_head *seq_head;
  	struct hlist_node *seq_node;
  	struct name_seq *seq;
  	int all_types;
  	u32 depth;
  	u32 i;
  
  	all_types = (depth_info & TIPC_NTQ_ALLTYPES);
  	depth = (depth_info & ~TIPC_NTQ_ALLTYPES);
  
  	if (depth == 0)
  		return;
  
  	if (all_types) {
  		/* display all entries in name table to specified depth */
  		nametbl_header(buf, depth);
  		lowbound = 0;
  		upbound = ~0;
  		for (i = 0; i < tipc_nametbl_size; i++) {
  			seq_head = &table.types[i];
  			hlist_for_each_entry(seq, seq_node, seq_head, ns_list) {

  				nameseq_list(seq, buf, depth, seq->type,

  					     lowbound, upbound, i);
  			}
  		}
  	} else {
  		/* display only the sequence that matches the specified type */
  		if (upbound < lowbound) {
  			tipc_printf(buf, "invalid name sequence specified
  ");
  			return;
  		}
  		nametbl_header(buf, depth);
  		i = hash(type);
  		seq_head = &table.types[i];
  		hlist_for_each_entry(seq, seq_node, seq_head, ns_list) {
  			if (seq->type == type) {

  				nameseq_list(seq, buf, depth, type,

  					     lowbound, upbound, i);
  				break;
  			}
  		}
  	}
  }

  #define MAX_NAME_TBL_QUERY 32768

  struct sk_buff *tipc_nametbl_get(const void *req_tlv_area, int req_tlv_space)

  {
  	struct sk_buff *buf;
  	struct tipc_name_table_query *argv;
  	struct tlv_desc *rep_tlv;
  	struct print_buf b;
  	int str_len;
  
  	if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_NAME_TBL_QUERY))

  		return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);

  	buf = tipc_cfg_reply_alloc(TLV_SPACE(MAX_NAME_TBL_QUERY));

  	if (!buf)
  		return NULL;
  
  	rep_tlv = (struct tlv_desc *)buf->data;

  	tipc_printbuf_init(&b, TLV_DATA(rep_tlv), MAX_NAME_TBL_QUERY);

  	argv = (struct tipc_name_table_query *)TLV_DATA(req_tlv_area);

  	read_lock_bh(&tipc_nametbl_lock);

  	nametbl_list(&b, ntohl(argv->depth), ntohl(argv->type),

  		     ntohl(argv->lowbound), ntohl(argv->upbound));

  	read_unlock_bh(&tipc_nametbl_lock);
  	str_len = tipc_printbuf_validate(&b);

  
  	skb_put(buf, TLV_SPACE(str_len));
  	TLV_SET(rep_tlv, TIPC_TLV_ULTRA_STRING, NULL, str_len);
  
  	return buf;
  }

  int tipc_nametbl_init(void)

  {

  	table.types = kcalloc(tipc_nametbl_size, sizeof(struct hlist_head),
  			      GFP_ATOMIC);

  	if (!table.types)
  		return -ENOMEM;

  	table.local_publ_count = 0;

  	return 0;
  }

  void tipc_nametbl_stop(void)

  {

  	u32 i;
  
  	if (!table.types)
  		return;

  	/* Verify name table is empty, then release it */

  	write_lock_bh(&tipc_nametbl_lock);

  	for (i = 0; i < tipc_nametbl_size; i++) {

  		if (!hlist_empty(&table.types[i]))
  			err("tipc_nametbl_stop(): hash chain %u is non-null
  ", i);

  	}
  	kfree(table.types);
  	table.types = NULL;

  	write_unlock_bh(&tipc_nametbl_lock);

  }