net/tipc/subscr.c - kernel/msm-4.19 - Gitiles

 /*
  * net/tipc/subscr.c: TIPC network topology service
  *
  * Copyright (c) 2000-2006, 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"

 /**
  * struct tipc_subscriber - TIPC network topology subscriber
  * @conid: connection identifier to server connecting to subscriber
  * @lock: control access to subscriber
  * @subscription_list: list of subscription objects for this subscriber
  */
 struct tipc_subscriber {
 	int conid;
 	spinlock_t lock;
 	struct list_head subscription_list;
 };

 /**
  * htohl - convert value to endianness used by destination
  * @in: value to convert
  * @swap: non-zero if endianness must be reversed
  *
  * Returns converted value
  */
 static u32 htohl(u32 in, int swap)
 {
 	return swap ? swab32(in) : in;
 }

 static void subscr_send_event(struct tipc_subscription *sub, u32 found_lower,
 			      u32 found_upper, u32 event, u32 port_ref,
 			      u32 node)
 {
 	struct tipc_net *tn = net_generic(sub->net, tipc_net_id);
 	struct tipc_subscriber *subscriber = sub->subscriber;
 	struct kvec msg_sect;

 	msg_sect.iov_base = (void *)&sub->evt;
 	msg_sect.iov_len = sizeof(struct tipc_event);
 	sub->evt.event = htohl(event, sub->swap);
 	sub->evt.found_lower = htohl(found_lower, sub->swap);
 	sub->evt.found_upper = htohl(found_upper, sub->swap);
 	sub->evt.port.ref = htohl(port_ref, sub->swap);
 	sub->evt.port.node = htohl(node, sub->swap);
 	tipc_conn_sendmsg(tn->topsrv, subscriber->conid, NULL,
 			  msg_sect.iov_base, msg_sect.iov_len);
 }

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

 /**
  * tipc_subscr_report_overlap - issue event if there is subscription overlap
  *
  * Protected by nameseq.lock in name_table.c
  */
 void tipc_subscr_report_overlap(struct tipc_subscription *sub, u32 found_lower,
 				u32 found_upper, u32 event, u32 port_ref,
 				u32 node, int must)
 {
 	if (!tipc_subscr_overlap(sub, found_lower, found_upper))
 		return;
 	if (!must && !(sub->filter & TIPC_SUB_PORTS))
 		return;

 	subscr_send_event(sub, found_lower, found_upper, event, port_ref, node);
 }

 static void subscr_timeout(unsigned long data)
 {
 	struct tipc_subscription *sub = (struct tipc_subscription *)data;
 	struct tipc_subscriber *subscriber = sub->subscriber;
 	struct tipc_net *tn = net_generic(sub->net, tipc_net_id);

 	/* The spin lock per subscriber is used to protect its members */
 	spin_lock_bh(&subscriber->lock);

 	/* Validate timeout (in case subscription is being cancelled) */
 	if (sub->timeout == TIPC_WAIT_FOREVER) {
 		spin_unlock_bh(&subscriber->lock);
 		return;
 	}

 	/* Unlink subscription from name table */
 	tipc_nametbl_unsubscribe(sub);

 	/* Unlink subscription from subscriber */
 	list_del(&sub->subscription_list);

 	spin_unlock_bh(&subscriber->lock);

 	/* Notify subscriber of timeout */
 	subscr_send_event(sub, sub->evt.s.seq.lower, sub->evt.s.seq.upper,
 			  TIPC_SUBSCR_TIMEOUT, 0, 0);

 	/* Now destroy subscription */
 	kfree(sub);
 	atomic_dec(&tn->subscription_count);
 }

 /**
  * subscr_del - delete a subscription within a subscription list
  *
  * Called with subscriber lock held.
  */
 static void subscr_del(struct tipc_subscription *sub)
 {
 	struct tipc_net *tn = net_generic(sub->net, tipc_net_id);

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

 /**
  * subscr_terminate - terminate communication with a subscriber
  *
  * Note: Must call it in process context since it might sleep.
  */
 static void subscr_terminate(struct tipc_subscription *sub)
 {
 	struct tipc_subscriber *subscriber = sub->subscriber;
 	struct tipc_net *tn = net_generic(sub->net, tipc_net_id);

 	tipc_conn_terminate(tn->topsrv, subscriber->conid);
 }

 static void subscr_release(struct tipc_subscriber *subscriber)
 {
 	struct tipc_subscription *sub;
 	struct tipc_subscription *sub_temp;

 	spin_lock_bh(&subscriber->lock);

 	/* Destroy any existing subscriptions for subscriber */
 	list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
 				 subscription_list) {
 		if (sub->timeout != TIPC_WAIT_FOREVER) {
 			spin_unlock_bh(&subscriber->lock);
 			del_timer_sync(&sub->timer);
 			spin_lock_bh(&subscriber->lock);
 		}
 		subscr_del(sub);
 	}
 	spin_unlock_bh(&subscriber->lock);

 	/* Now destroy subscriber */
 	kfree(subscriber);
 }

 /**
  * subscr_cancel - handle subscription cancellation request
  *
  * Called with subscriber lock held. Routine must temporarily release lock
  * to enable the subscription timeout routine to finish without deadlocking;
  * the lock is then reclaimed to allow caller to release it upon return.
  *
  * Note that fields of 's' use subscriber's endianness!
  */
 static void subscr_cancel(struct tipc_subscr *s,
 			  struct tipc_subscriber *subscriber)
 {
 	struct tipc_subscription *sub;
 	struct tipc_subscription *sub_temp;
 	int found = 0;

 	/* Find first matching subscription, exit if not found */
 	list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
 				 subscription_list) {
 		if (!memcmp(s, &sub->evt.s, sizeof(struct tipc_subscr))) {
 			found = 1;
 			break;
 		}
 	}
 	if (!found)
 		return;

 	/* Cancel subscription timer (if used), then delete subscription */
 	if (sub->timeout != TIPC_WAIT_FOREVER) {
 		sub->timeout = TIPC_WAIT_FOREVER;
 		spin_unlock_bh(&subscriber->lock);
 		del_timer_sync(&sub->timer);
 		spin_lock_bh(&subscriber->lock);
 	}
 	subscr_del(sub);
 }

 /**
  * subscr_subscribe - create subscription for subscriber
  *
  * Called with subscriber lock held.
  */
 static int subscr_subscribe(struct net *net, struct tipc_subscr *s,
 			    struct tipc_subscriber *subscriber,
 			    struct tipc_subscription **sub_p)
 {
 	struct tipc_net *tn = net_generic(net, tipc_net_id);
 	struct tipc_subscription *sub;
 	int swap;

 	/* Determine subscriber's endianness */
 	swap = !(s->filter & (TIPC_SUB_PORTS | TIPC_SUB_SERVICE));

 	/* Detect & process a subscription cancellation request */
 	if (s->filter & htohl(TIPC_SUB_CANCEL, swap)) {
 		s->filter &= ~htohl(TIPC_SUB_CANCEL, swap);
 		subscr_cancel(s, subscriber);
 		return 0;
 	}

 	/* 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 -EINVAL;
 	}

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

 	/* Initialize subscription object */
 	sub->net = net;
 	sub->seq.type = htohl(s->seq.type, swap);
 	sub->seq.lower = htohl(s->seq.lower, swap);
 	sub->seq.upper = htohl(s->seq.upper, swap);
 	sub->timeout = msecs_to_jiffies(htohl(s->timeout, swap));
 	sub->filter = htohl(s->filter, swap);
 	if ((!(sub->filter & TIPC_SUB_PORTS) ==
 	     !(sub->filter & TIPC_SUB_SERVICE)) ||
 	    (sub->seq.lower > sub->seq.upper)) {
 		pr_warn("Subscription rejected, illegal request\n");
 		kfree(sub);
 		return -EINVAL;
 	}
 	list_add(&sub->subscription_list, &subscriber->subscription_list);
 	sub->subscriber = subscriber;
 	sub->swap = swap;
 	memcpy(&sub->evt.s, s, sizeof(struct tipc_subscr));
 	atomic_inc(&tn->subscription_count);
 	if (sub->timeout != TIPC_WAIT_FOREVER) {
 		setup_timer(&sub->timer, subscr_timeout, (unsigned long)sub);
 		mod_timer(&sub->timer, jiffies + sub->timeout);
 	}
 	*sub_p = sub;
 	return 0;
 }

 /* Handle one termination request for the subscriber */
 static void subscr_conn_shutdown_event(int conid, void *usr_data)
 {
 	subscr_release((struct tipc_subscriber *)usr_data);
 }

 /* Handle one request to create a new subscription for the subscriber */
 static void subscr_conn_msg_event(struct net *net, int conid,
 				  struct sockaddr_tipc *addr, void *usr_data,
 				  void *buf, size_t len)
 {
 	struct tipc_subscriber *subscriber = usr_data;
 	struct tipc_subscription *sub = NULL;

 	spin_lock_bh(&subscriber->lock);
 	if (subscr_subscribe(net, (struct tipc_subscr *)buf, subscriber,
 			     &sub) < 0) {
 		spin_unlock_bh(&subscriber->lock);
 		subscr_terminate(sub);
 		return;
 	}
 	if (sub)
 		tipc_nametbl_subscribe(sub);
 	spin_unlock_bh(&subscriber->lock);
 }

 /* Handle one request to establish a new subscriber */
 static void *subscr_named_msg_event(int conid)
 {
 	struct tipc_subscriber *subscriber;

 	/* Create subscriber object */
 	subscriber = kzalloc(sizeof(struct tipc_subscriber), GFP_ATOMIC);
 	if (subscriber == NULL) {
 		pr_warn("Subscriber rejected, no memory\n");
 		return NULL;
 	}
 	INIT_LIST_HEAD(&subscriber->subscription_list);
 	subscriber->conid = conid;
 	spin_lock_init(&subscriber->lock);

 	return (void *)subscriber;
 }

 int tipc_subscr_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->imp			= TIPC_CRITICAL_IMPORTANCE;
 	topsrv->type			= SOCK_SEQPACKET;
 	topsrv->max_rcvbuf_size		= sizeof(struct tipc_subscr);
 	topsrv->tipc_conn_recvmsg	= subscr_conn_msg_event;
 	topsrv->tipc_conn_new		= subscr_named_msg_event;
 	topsrv->tipc_conn_shutdown	= subscr_conn_shutdown_event;

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

 	return tipc_server_start(topsrv);
 }

 void tipc_subscr_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);
 }
	/*
	* net/tipc/subscr.c: TIPC network topology service
	*
	* Copyright (c) 2000-2006, 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"

	/**
	* struct tipc_subscriber - TIPC network topology subscriber
	* @conid: connection identifier to server connecting to subscriber
	* @lock: control access to subscriber
	* @subscription_list: list of subscription objects for this subscriber
	*/
	struct tipc_subscriber {
	int conid;
	spinlock_t lock;
	struct list_head subscription_list;
	};

	/**
	* htohl - convert value to endianness used by destination
	* @in: value to convert
	* @swap: non-zero if endianness must be reversed
	*
	* Returns converted value
	*/
	static u32 htohl(u32 in, int swap)
	{
	return swap ? swab32(in) : in;
	}

	static void subscr_send_event(struct tipc_subscription *sub, u32 found_lower,
	u32 found_upper, u32 event, u32 port_ref,
	u32 node)
	{
	struct tipc_net *tn = net_generic(sub->net, tipc_net_id);
	struct tipc_subscriber *subscriber = sub->subscriber;
	struct kvec msg_sect;

	msg_sect.iov_base = (void *)&sub->evt;
	msg_sect.iov_len = sizeof(struct tipc_event);
	sub->evt.event = htohl(event, sub->swap);
	sub->evt.found_lower = htohl(found_lower, sub->swap);
	sub->evt.found_upper = htohl(found_upper, sub->swap);
	sub->evt.port.ref = htohl(port_ref, sub->swap);
	sub->evt.port.node = htohl(node, sub->swap);
	tipc_conn_sendmsg(tn->topsrv, subscriber->conid, NULL,
	msg_sect.iov_base, msg_sect.iov_len);
	}

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

	/**
	* tipc_subscr_report_overlap - issue event if there is subscription overlap
	*
	* Protected by nameseq.lock in name_table.c
	*/
	void tipc_subscr_report_overlap(struct tipc_subscription *sub, u32 found_lower,
	u32 found_upper, u32 event, u32 port_ref,
	u32 node, int must)
	{
	if (!tipc_subscr_overlap(sub, found_lower, found_upper))
	return;
	if (!must && !(sub->filter & TIPC_SUB_PORTS))
	return;

	subscr_send_event(sub, found_lower, found_upper, event, port_ref, node);
	}

	static void subscr_timeout(unsigned long data)
	{
	struct tipc_subscription sub = (struct tipc_subscription )data;
	struct tipc_subscriber *subscriber = sub->subscriber;
	struct tipc_net *tn = net_generic(sub->net, tipc_net_id);

	/* The spin lock per subscriber is used to protect its members */
	spin_lock_bh(&subscriber->lock);

	/* Validate timeout (in case subscription is being cancelled) */
	if (sub->timeout == TIPC_WAIT_FOREVER) {
	spin_unlock_bh(&subscriber->lock);
	return;
	}

	/* Unlink subscription from name table */
	tipc_nametbl_unsubscribe(sub);

	/* Unlink subscription from subscriber */
	list_del(&sub->subscription_list);

	spin_unlock_bh(&subscriber->lock);

	/* Notify subscriber of timeout */
	subscr_send_event(sub, sub->evt.s.seq.lower, sub->evt.s.seq.upper,
	TIPC_SUBSCR_TIMEOUT, 0, 0);

	/* Now destroy subscription */
	kfree(sub);
	atomic_dec(&tn->subscription_count);
	}

	/**
	* subscr_del - delete a subscription within a subscription list
	*
	* Called with subscriber lock held.
	*/
	static void subscr_del(struct tipc_subscription *sub)
	{
	struct tipc_net *tn = net_generic(sub->net, tipc_net_id);

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

	/**
	* subscr_terminate - terminate communication with a subscriber
	*
	* Note: Must call it in process context since it might sleep.
	*/
	static void subscr_terminate(struct tipc_subscription *sub)
	{
	struct tipc_subscriber *subscriber = sub->subscriber;
	struct tipc_net *tn = net_generic(sub->net, tipc_net_id);

	tipc_conn_terminate(tn->topsrv, subscriber->conid);
	}

	static void subscr_release(struct tipc_subscriber *subscriber)
	{
	struct tipc_subscription *sub;
	struct tipc_subscription *sub_temp;

	spin_lock_bh(&subscriber->lock);

	/* Destroy any existing subscriptions for subscriber */
	list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
	subscription_list) {
	if (sub->timeout != TIPC_WAIT_FOREVER) {
	spin_unlock_bh(&subscriber->lock);
	del_timer_sync(&sub->timer);
	spin_lock_bh(&subscriber->lock);
	}
	subscr_del(sub);
	}
	spin_unlock_bh(&subscriber->lock);

	/* Now destroy subscriber */
	kfree(subscriber);
	}

	/**
	* subscr_cancel - handle subscription cancellation request
	*
	* Called with subscriber lock held. Routine must temporarily release lock
	* to enable the subscription timeout routine to finish without deadlocking;
	* the lock is then reclaimed to allow caller to release it upon return.
	*
	* Note that fields of 's' use subscriber's endianness!
	*/
	static void subscr_cancel(struct tipc_subscr *s,
	struct tipc_subscriber *subscriber)
	{
	struct tipc_subscription *sub;
	struct tipc_subscription *sub_temp;
	int found = 0;

	/* Find first matching subscription, exit if not found */
	list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
	subscription_list) {
	if (!memcmp(s, &sub->evt.s, sizeof(struct tipc_subscr))) {
	found = 1;
	break;
	}
	}
	if (!found)
	return;

	/* Cancel subscription timer (if used), then delete subscription */
	if (sub->timeout != TIPC_WAIT_FOREVER) {
	sub->timeout = TIPC_WAIT_FOREVER;
	spin_unlock_bh(&subscriber->lock);
	del_timer_sync(&sub->timer);
	spin_lock_bh(&subscriber->lock);
	}
	subscr_del(sub);
	}

	/**
	* subscr_subscribe - create subscription for subscriber
	*
	* Called with subscriber lock held.
	*/
	static int subscr_subscribe(struct net net, struct tipc_subscr s,
	struct tipc_subscriber *subscriber,
	struct tipc_subscription **sub_p)
	{
	struct tipc_net *tn = net_generic(net, tipc_net_id);
	struct tipc_subscription *sub;
	int swap;

	/* Determine subscriber's endianness */
	swap = !(s->filter & (TIPC_SUB_PORTS \| TIPC_SUB_SERVICE));

	/* Detect & process a subscription cancellation request */
	if (s->filter & htohl(TIPC_SUB_CANCEL, swap)) {
	s->filter &= ~htohl(TIPC_SUB_CANCEL, swap);
	subscr_cancel(s, subscriber);
	return 0;
	}

	/* 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 -EINVAL;
	}

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

	/* Initialize subscription object */
	sub->net = net;
	sub->seq.type = htohl(s->seq.type, swap);
	sub->seq.lower = htohl(s->seq.lower, swap);
	sub->seq.upper = htohl(s->seq.upper, swap);
	sub->timeout = msecs_to_jiffies(htohl(s->timeout, swap));
	sub->filter = htohl(s->filter, swap);
	if ((!(sub->filter & TIPC_SUB_PORTS) ==
	!(sub->filter & TIPC_SUB_SERVICE)) \|\|
	(sub->seq.lower > sub->seq.upper)) {
	pr_warn("Subscription rejected, illegal request\n");
	kfree(sub);
	return -EINVAL;
	}
	list_add(&sub->subscription_list, &subscriber->subscription_list);
	sub->subscriber = subscriber;
	sub->swap = swap;
	memcpy(&sub->evt.s, s, sizeof(struct tipc_subscr));
	atomic_inc(&tn->subscription_count);
	if (sub->timeout != TIPC_WAIT_FOREVER) {
	setup_timer(&sub->timer, subscr_timeout, (unsigned long)sub);
	mod_timer(&sub->timer, jiffies + sub->timeout);
	}
	*sub_p = sub;
	return 0;
	}

	/* Handle one termination request for the subscriber */
	static void subscr_conn_shutdown_event(int conid, void *usr_data)
	{
	subscr_release((struct tipc_subscriber *)usr_data);
	}

	/* Handle one request to create a new subscription for the subscriber */
	static void subscr_conn_msg_event(struct net *net, int conid,
	struct sockaddr_tipc addr, void usr_data,
	void *buf, size_t len)
	{
	struct tipc_subscriber *subscriber = usr_data;
	struct tipc_subscription *sub = NULL;

	spin_lock_bh(&subscriber->lock);
	if (subscr_subscribe(net, (struct tipc_subscr *)buf, subscriber,
	&sub) < 0) {
	spin_unlock_bh(&subscriber->lock);
	subscr_terminate(sub);
	return;
	}
	if (sub)
	tipc_nametbl_subscribe(sub);
	spin_unlock_bh(&subscriber->lock);
	}

	/* Handle one request to establish a new subscriber */
	static void *subscr_named_msg_event(int conid)
	{
	struct tipc_subscriber *subscriber;

	/* Create subscriber object */
	subscriber = kzalloc(sizeof(struct tipc_subscriber), GFP_ATOMIC);
	if (subscriber == NULL) {
	pr_warn("Subscriber rejected, no memory\n");
	return NULL;
	}
	INIT_LIST_HEAD(&subscriber->subscription_list);
	subscriber->conid = conid;
	spin_lock_init(&subscriber->lock);

	return (void *)subscriber;
	}

	int tipc_subscr_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->imp = TIPC_CRITICAL_IMPORTANCE;
	topsrv->type = SOCK_SEQPACKET;
	topsrv->max_rcvbuf_size = sizeof(struct tipc_subscr);
	topsrv->tipc_conn_recvmsg = subscr_conn_msg_event;
	topsrv->tipc_conn_new = subscr_named_msg_event;
	topsrv->tipc_conn_shutdown = subscr_conn_shutdown_event;

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

	return tipc_server_start(topsrv);
	}

	void tipc_subscr_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);
	}