net/tipc/subscr.c

/*
 * net/tipc/subscr.c: TIPC network topology service
 *
 * Copyright (c) 2000-2017, Ericsson AB
 * Copyright (c) 2005-2007, 2010-2013, 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 "name_table.h"
#include "subscr.h"

static void tipc_subscrp_send_event(struct tipc_subscription *sub,
				    u32 found_lower, u32 found_upper,
				    u32 event, u32 port, u32 node)
{
	struct tipc_event *evt = &sub->evt;

	if (sub->inactive)
		return;
	tipc_evt_write(evt, event, event);
	tipc_evt_write(evt, found_lower, found_lower);
	tipc_evt_write(evt, found_upper, found_upper);
	tipc_evt_write(evt, port.ref, port);
	tipc_evt_write(evt, port.node, node);
	tipc_conn_queue_evt(sub->server, sub->conid, event, evt);
}

/**
 * tipc_subscrp_check_overlap - test for subscription overlap with the
 * given values
 *
 * Returns 1 if there is overlap, otherwise 0.
 */
int tipc_subscrp_check_overlap(struct tipc_name_seq *seq, u32 found_lower,
			       u32 found_upper)
{
	if (found_lower < seq->lower)
		found_lower = seq->lower;
	if (found_upper > seq->upper)
		found_upper = seq->upper;
	if (found_lower > found_upper)
		return 0;
	return 1;
}

void tipc_subscrp_report_overlap(struct tipc_subscription *sub,
				 u32 found_lower, u32 found_upper,
				 u32 event, u32 port, u32 node,
				 u32 scope, int must)
{
	struct tipc_name_seq seq;
	struct tipc_subscr *s = &sub->evt.s;
	u32 filter = tipc_sub_read(s, filter);

	seq.type = tipc_sub_read(s, seq.type);
	seq.lower = tipc_sub_read(s, seq.lower);
	seq.upper = tipc_sub_read(s, seq.upper);

	if (!tipc_subscrp_check_overlap(&seq, found_lower, found_upper))
		return;

	if (!must && !(filter & TIPC_SUB_PORTS))
		return;
	if (filter & TIPC_SUB_CLUSTER_SCOPE && scope == TIPC_NODE_SCOPE)
		return;
	if (filter & TIPC_SUB_NODE_SCOPE && scope != TIPC_NODE_SCOPE)
		return;
	spin_lock(&sub->lock);
	tipc_subscrp_send_event(sub, found_lower, found_upper,
				event, port, node);
	spin_unlock(&sub->lock);
}

static void tipc_subscrp_timeout(struct timer_list *t)
{
	struct tipc_subscription *sub = from_timer(sub, t, timer);
	struct tipc_subscr *s = &sub->evt.s;

	spin_lock(&sub->lock);
	tipc_subscrp_send_event(sub, s->seq.lower, s->seq.upper,
				TIPC_SUBSCR_TIMEOUT, 0, 0);
	sub->inactive = true;
	spin_unlock(&sub->lock);
}

static void tipc_subscrp_kref_release(struct kref *kref)
{
	struct tipc_subscription *sub;
	struct tipc_net *tn;

	sub = container_of(kref, struct tipc_subscription, kref);
	tn = tipc_net(sub->server->net);

	atomic_dec(&tn->subscription_count);
	kfree(sub);
}

void tipc_subscrp_put(struct tipc_subscription *subscription)
{
	kref_put(&subscription->kref, tipc_subscrp_kref_release);
}

void tipc_subscrp_get(struct tipc_subscription *subscription)
{
	kref_get(&subscription->kref);
}

static struct tipc_subscription *tipc_subscrp_create(struct tipc_server *srv,
						     struct tipc_subscr *s,
						     int conid)
{
	struct tipc_net *tn = tipc_net(srv->net);
	struct tipc_subscription *sub;
	u32 filter = tipc_sub_read(s, filter);

	/* Refuse subscription if global limit exceeded */
	if (atomic_read(&tn->subscription_count) >= TIPC_MAX_SUBSCRIPTIONS) {
		pr_warn("Subscription rejected, limit reached (%u)\n",
			TIPC_MAX_SUBSCRIPTIONS);
		return NULL;
	}

	/* Allocate subscription object */
	sub = kmalloc(sizeof(*sub), GFP_ATOMIC);
	if (!sub) {
		pr_warn("Subscription rejected, no memory\n");
		return NULL;
	}

	/* Initialize subscription object */
	if (filter & TIPC_SUB_PORTS && filter & TIPC_SUB_SERVICE)
		goto err;
	if (tipc_sub_read(s, seq.lower) > tipc_sub_read(s, seq.upper))
		goto err;
	sub->server = srv;
	sub->conid = conid;
	sub->inactive = false;
	memcpy(&sub->evt.s, s, sizeof(*s));
	spin_lock_init(&sub->lock);
	atomic_inc(&tn->subscription_count);
	kref_init(&sub->kref);
	return sub;
err:
	pr_warn("Subscription rejected, illegal request\n");
	kfree(sub);
	return NULL;
}

struct tipc_subscription *tipc_subscrp_subscribe(struct tipc_server *srv,
						 struct tipc_subscr *s,
						 int conid)
{
	struct tipc_subscription *sub = NULL;
	u32 timeout;

	sub = tipc_subscrp_create(srv, s, conid);
	if (!sub)
		return NULL;

	tipc_nametbl_subscribe(sub);
	timer_setup(&sub->timer, tipc_subscrp_timeout, 0);
	timeout = tipc_sub_read(&sub->evt.s, timeout);
	if (timeout != TIPC_WAIT_FOREVER)
		mod_timer(&sub->timer, jiffies + msecs_to_jiffies(timeout));
	return sub;
}

void tipc_sub_delete(struct tipc_subscription *sub)
{
	tipc_nametbl_unsubscribe(sub);
	if (sub->evt.s.timeout != TIPC_WAIT_FOREVER)
		del_timer_sync(&sub->timer);
	list_del(&sub->subscrp_list);
	tipc_subscrp_put(sub);
}

int tipc_topsrv_start(struct net *net)
{
	struct tipc_net *tn = net_generic(net, tipc_net_id);
	const char name[] = "topology_server";
	struct tipc_server *topsrv;
	struct sockaddr_tipc *saddr;

	saddr = kzalloc(sizeof(*saddr), GFP_ATOMIC);
	if (!saddr)
		return -ENOMEM;
	saddr->family			= AF_TIPC;
	saddr->addrtype			= TIPC_ADDR_NAMESEQ;
	saddr->addr.nameseq.type	= TIPC_TOP_SRV;
	saddr->addr.nameseq.lower	= TIPC_TOP_SRV;
	saddr->addr.nameseq.upper	= TIPC_TOP_SRV;
	saddr->scope			= TIPC_NODE_SCOPE;

	topsrv = kzalloc(sizeof(*topsrv), GFP_ATOMIC);
	if (!topsrv) {
		kfree(saddr);
		return -ENOMEM;
	}
	topsrv->net			= net;
	topsrv->saddr			= saddr;
	topsrv->max_rcvbuf_size		= sizeof(struct tipc_subscr);

	strncpy(topsrv->name, name, strlen(name) + 1);
	tn->topsrv = topsrv;
	atomic_set(&tn->subscription_count, 0);

	return tipc_server_start(topsrv);
}

void tipc_topsrv_stop(struct net *net)
{
	struct tipc_net *tn = net_generic(net, tipc_net_id);
	struct tipc_server *topsrv = tn->topsrv;

	tipc_server_stop(topsrv);
	kfree(topsrv->saddr);
	kfree(topsrv);
}