path: root/net/tipc/name_table.c

/*
 * net/tipc/name_table.c: TIPC name table code
 *
 * Copyright (c) 2000-2006, 2014-2018, Ericsson AB
 * Copyright (c) 2004-2008, 2010-2014, 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 <net/sock.h>
#include "core.h"
#include "netlink.h"
#include "name_table.h"
#include "name_distr.h"
#include "subscr.h"
#include "bcast.h"
#include "addr.h"
#include "node.h"
#include "group.h"
#include <net/genetlink.h>

#define TIPC_NAMETBL_SIZE 1024		/* must be a power of 2 */

/**
 * struct name_info - name sequence publication info
 * @node_list: list of publications on own node of this <type,lower,upper>
 * @all_publ: list of all publications of this <type,lower,upper>
 */
struct name_info {
	struct list_head local_publ;
	struct list_head all_publ;
};

/**
 * 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
 * @rcu: RCU callback head used for deferred freeing
 */
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 rcu_head rcu;
};

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,
				       u32 key)
{
	struct publication *publ = kzalloc(sizeof(*publ), GFP_ATOMIC);
	if (publ == NULL) {
		pr_warn("Publication creation failure, no memory\n");
		return NULL;
	}

	publ->type = type;
	publ->lower = lower;
	publ->upper = upper;
	publ->scope = scope;
	publ->node = node;
	publ->port = port;
	publ->key = key;
	INIT_LIST_HEAD(&publ->binding_sock);
	return publ;
}

/**
 * tipc_subseq_alloc - allocate a specified number of sub-sequence structures
 */
static struct sub_seq *tipc_subseq_alloc(u32 cnt)
{
	return kcalloc(cnt, sizeof(struct sub_seq), GFP_ATOMIC);
}

/**
 * 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) {
		pr_warn("Name sequence creation failed, no memory\n");
		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_rcu(&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</