net/tipc/subscr.c - kernel/msm-4.9 - Gitiles

 /*
  * net/tipc/subscr.c: TIPC subscription service
  *
  * Copyright (c) 2000-2006, Ericsson AB
  * Copyright (c) 2005, 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 "dbg.h"
 #include "subscr.h"
 #include "name_table.h"
 #include "ref.h"

 /**
  * struct subscriber - TIPC network topology subscriber
  * @ref: object reference to subscriber object itself
  * @lock: pointer to spinlock controlling access to subscriber object
  * @subscriber_list: adjacent subscribers in top. server's list of subscribers
  * @subscription_list: list of subscription objects for this subscriber
  * @port_ref: object reference to port used to communicate with subscriber
  * @swap: indicates if subscriber uses opposite endianness in its messages
  */

 struct subscriber {
 	u32 ref;
         spinlock_t *lock;
 	struct list_head subscriber_list;
 	struct list_head subscription_list;
 	u32 port_ref;
 	int swap;
 };

 /**
  * struct top_srv - TIPC network topology subscription service
  * @user_ref: TIPC userid of subscription service
  * @setup_port: reference to TIPC port that handles subscription requests
  * @subscription_count: number of active subscriptions (not subscribers!)
  * @subscriber_list: list of ports subscribing to service
  * @lock: spinlock govering access to subscriber list
  */

 struct top_srv {
 	u32 user_ref;
 	u32 setup_port;
 	atomic_t subscription_count;
 	struct list_head subscriber_list;
 	spinlock_t lock;
 };

 static struct top_srv topsrv = { 0 };

 /**
  * 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)
 {
 	char *c = (char *)&in;

 	return swap ? ((c[3] << 3) + (c[2] << 2) + (c[1] << 1) + c[0]) : in;
 }

 /**
  * subscr_send_event - send a message containing a tipc_event to the subscriber
  */

 static void subscr_send_event(struct subscription *sub,
 			      u32 found_lower,
 			      u32 found_upper,
 			      u32 event,
 			      u32 port_ref,
 			      u32 node)
 {
 	struct iovec msg_sect;

 	msg_sect.iov_base = (void *)&sub->evt;
 	msg_sect.iov_len = sizeof(struct tipc_event);

 	sub->evt.event = htohl(event, sub->owner->swap);
 	sub->evt.found_lower = htohl(found_lower, sub->owner->swap);
 	sub->evt.found_upper = htohl(found_upper, sub->owner->swap);
 	sub->evt.port.ref = htohl(port_ref, sub->owner->swap);
 	sub->evt.port.node = htohl(node, sub->owner->swap);
 	tipc_send(sub->owner->port_ref, 1, &msg_sect);
 }

 /**
  * tipc_subscr_overlap - test for subscription overlap with the given values
  *
  * Returns 1 if there is overlap, otherwise 0.
  */

 int tipc_subscr_overlap(struct 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 subscription *sub,
 				u32 found_lower,
 				u32 found_upper,
 				u32 event,
 				u32 port_ref,
 				u32 node,
 				int must)
 {
 	dbg("Rep overlap %u:%u,%u<->%u,%u\n", sub->seq.type, sub->seq.lower,
 	    sub->seq.upper, found_lower, found_upper);
 	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);
 }

 /**
  * subscr_timeout - subscription timeout has occurred
  */

 static void subscr_timeout(struct subscription *sub)
 {
 	struct subscriber *subscriber;
 	u32 subscriber_ref;

 	/* Validate subscriber reference (in case subscriber is terminating) */

 	subscriber_ref = sub->owner->ref;
 	subscriber = (struct subscriber *)tipc_ref_lock(subscriber_ref);
 	if (subscriber == NULL)
 		return;

 	/* Validate timeout (in case subscription is being cancelled) */

 	if (sub->timeout == TIPC_WAIT_FOREVER) {
 		tipc_ref_unlock(subscriber_ref);
 		return;
 	}

 	/* Unlink subscription from name table */

 	tipc_nametbl_unsubscribe(sub);

 	/* Notify subscriber of timeout, then unlink subscription */

 	subscr_send_event(sub,
 			  sub->evt.s.seq.lower,
 			  sub->evt.s.seq.upper,
 			  TIPC_SUBSCR_TIMEOUT,
 			  0,
 			  0);
 	list_del(&sub->subscription_list);

 	/* Now destroy subscription */

 	tipc_ref_unlock(subscriber_ref);
 	k_term_timer(&sub->timer);
 	kfree(sub);
 	atomic_dec(&topsrv.subscription_count);
 }

 /**
  * subscr_del - delete a subscription within a subscription list
  *
  * Called with subscriber locked.
  */

 static void subscr_del(struct subscription *sub)
 {
 	tipc_nametbl_unsubscribe(sub);
 	list_del(&sub->subscription_list);
 	kfree(sub);
 	atomic_dec(&topsrv.subscription_count);
 }

 /**
  * subscr_terminate - terminate communication with a subscriber
  *
  * Called with subscriber locked.  Routine must temporarily release this lock
  * to enable subscription timeout routine(s) to finish without deadlocking;
  * the lock is then reclaimed to allow caller to release it upon return.
  * (This should work even in the unlikely event some other thread creates
  * a new object reference in the interim that uses this lock; this routine will
  * simply wait for it to be released, then claim it.)
  */

 static void subscr_terminate(struct subscriber *subscriber)
 {
 	struct subscription *sub;
 	struct subscription *sub_temp;

 	/* Invalidate subscriber reference */

 	tipc_ref_discard(subscriber->ref);
 	spin_unlock_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) {
 			k_cancel_timer(&sub->timer);
 			k_term_timer(&sub->timer);
 		}
 		dbg("Term: Removing sub %u,%u,%u from subscriber %x list\n",
 		    sub->seq.type, sub->seq.lower, sub->seq.upper, subscriber);
 		subscr_del(sub);
 	}

 	/* Sever connection to subscriber */

 	tipc_shutdown(subscriber->port_ref);
 	tipc_deleteport(subscriber->port_ref);

 	/* Remove subscriber from topology server's subscriber list */

 	spin_lock_bh(&topsrv.lock);
 	list_del(&subscriber->subscriber_list);
 	spin_unlock_bh(&topsrv.lock);

 	/* Now destroy subscriber */

 	spin_lock_bh(subscriber->lock);
 	kfree(subscriber);
 }

 /**
  * subscr_cancel - handle subscription cancellation request
  *
  * Called with subscriber locked.  Routine must temporarily release this 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 subscriber *subscriber)
 {
 	struct subscription *sub;
 	struct 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);
 		k_cancel_timer(&sub->timer);
 		k_term_timer(&sub->timer);
 		spin_lock_bh(subscriber->lock);
 	}
 	dbg("Cancel: removing sub %u,%u,%u from subscriber %x list\n",
 	    sub->seq.type, sub->seq.lower, sub->seq.upper, subscriber);
 	subscr_del(sub);
 }

 /**
  * subscr_subscribe - create subscription for subscriber
  *
  * Called with subscriber locked
  */

 static void subscr_subscribe(struct tipc_subscr *s,
 			     struct subscriber *subscriber)
 {
 	struct subscription *sub;

 	/* Determine/update subscriber's endianness */

 	if (s->filter & (TIPC_SUB_PORTS | TIPC_SUB_SERVICE))
 		subscriber->swap = 0;
 	else
 		subscriber->swap = 1;

 	/* Detect & process a subscription cancellation request */

 	if (s->filter & htohl(TIPC_SUB_CANCEL, subscriber->swap)) {
 		s->filter &= ~htohl(TIPC_SUB_CANCEL, subscriber->swap);
 		subscr_cancel(s, subscriber);
 		return;
 	}

 	/* Refuse subscription if global limit exceeded */

 	if (atomic_read(&topsrv.subscription_count) >= tipc_max_subscriptions) {
 		warn("Subscription rejected, subscription limit reached (%u)\n",
 		     tipc_max_subscriptions);
 		subscr_terminate(subscriber);
 		return;
 	}

 	/* Allocate subscription object */

 	sub = kmalloc(sizeof(*sub), GFP_ATOMIC);
 	if (!sub) {
 		warn("Subscription rejected, no memory\n");
 		subscr_terminate(subscriber);
 		return;
 	}

 	/* Initialize subscription object */

 	memset(sub, 0, sizeof(*sub));
 	sub->seq.type = htohl(s->seq.type, subscriber->swap);
 	sub->seq.lower = htohl(s->seq.lower, subscriber->swap);
 	sub->seq.upper = htohl(s->seq.upper, subscriber->swap);
 	sub->timeout = htohl(s->timeout, subscriber->swap);
 	sub->filter = htohl(s->filter, subscriber->swap);
 	if ((!(sub->filter & TIPC_SUB_PORTS)
 	     == !(sub->filter & TIPC_SUB_SERVICE))
 	    || (sub->seq.lower > sub->seq.upper)) {
 		warn("Subscription rejected, illegal request\n");
 		kfree(sub);
 		subscr_terminate(subscriber);
 		return;
 	}
 	memcpy(&sub->evt.s, s, sizeof(struct tipc_subscr));
 	INIT_LIST_HEAD(&sub->subscription_list);
 	INIT_LIST_HEAD(&sub->nameseq_list);
 	list_add(&sub->subscription_list, &subscriber->subscription_list);
 	atomic_inc(&topsrv.subscription_count);
 	if (sub->timeout != TIPC_WAIT_FOREVER) {
 		k_init_timer(&sub->timer,
 			     (Handler)subscr_timeout, (unsigned long)sub);
 		k_start_timer(&sub->timer, sub->timeout);
 	}
 	sub->owner = subscriber;
 	tipc_nametbl_subscribe(sub);
 }

 /**
  * subscr_conn_shutdown_event - handle termination request from subscriber
  */

 static void subscr_conn_shutdown_event(void *usr_handle,
 				       u32 portref,
 				       struct sk_buff **buf,
 				       unsigned char const *data,
 				       unsigned int size,
 				       int reason)
 {
 	struct subscriber *subscriber;
 	spinlock_t *subscriber_lock;

 	subscriber = tipc_ref_lock((u32)(unsigned long)usr_handle);
 	if (subscriber == NULL)
 		return;

 	subscriber_lock = subscriber->lock;
 	subscr_terminate(subscriber);
 	spin_unlock_bh(subscriber_lock);
 }

 /**
  * subscr_conn_msg_event - handle new subscription request from subscriber
  */

 static void subscr_conn_msg_event(void *usr_handle,
 				  u32 port_ref,
 				  struct sk_buff **buf,
 				  const unchar *data,
 				  u32 size)
 {
 	struct subscriber *subscriber;
 	spinlock_t *subscriber_lock;

 	subscriber = tipc_ref_lock((u32)(unsigned long)usr_handle);
 	if (subscriber == NULL)
 		return;

 	subscriber_lock = subscriber->lock;
 	if (size != sizeof(struct tipc_subscr))
 		subscr_terminate(subscriber);
 	else
 		subscr_subscribe((struct tipc_subscr *)data, subscriber);

 	spin_unlock_bh(subscriber_lock);
 }

 /**
  * subscr_named_msg_event - handle request to establish a new subscriber
  */

 static void subscr_named_msg_event(void *usr_handle,
 				   u32 port_ref,
 				   struct sk_buff **buf,
 				   const unchar *data,
 				   u32 size,
 				   u32 importance,
 				   struct tipc_portid const *orig,
 				   struct tipc_name_seq const *dest)
 {
 	struct subscriber *subscriber;
 	struct iovec msg_sect = {NULL, 0};
 	spinlock_t *subscriber_lock;

 	dbg("subscr_named_msg_event: orig = %x own = %x,\n",
 	    orig->node, tipc_own_addr);
 	if (size && (size != sizeof(struct tipc_subscr))) {
 		warn("Subscriber rejected, invalid subscription size\n");
 		return;
 	}

 	/* Create subscriber object */

 	subscriber = kzalloc(sizeof(struct subscriber), GFP_ATOMIC);
 	if (subscriber == NULL) {
 		warn("Subscriber rejected, no memory\n");
 		return;
 	}
 	INIT_LIST_HEAD(&subscriber->subscription_list);
 	INIT_LIST_HEAD(&subscriber->subscriber_list);
 	subscriber->ref = tipc_ref_acquire(subscriber, &subscriber->lock);
 	if (subscriber->ref == 0) {
 		warn("Subscriber rejected, reference table exhausted\n");
 		kfree(subscriber);
 		return;
 	}

 	/* Establish a connection to subscriber */

 	tipc_createport(topsrv.user_ref,
 			(void *)(unsigned long)subscriber->ref,
 			importance,
 			NULL,
 			NULL,
 			subscr_conn_shutdown_event,
 			NULL,
 			NULL,
 			subscr_conn_msg_event,
 			NULL,
 			&subscriber->port_ref);
 	if (subscriber->port_ref == 0) {
 		warn("Subscriber rejected, unable to create port\n");
 		tipc_ref_discard(subscriber->ref);
 		kfree(subscriber);
 		return;
 	}
 	tipc_connect2port(subscriber->port_ref, orig);


 	/* Add subscriber to topology server's subscriber list */

 	tipc_ref_lock(subscriber->ref);
 	spin_lock_bh(&topsrv.lock);
 	list_add(&subscriber->subscriber_list, &topsrv.subscriber_list);
 	spin_unlock_bh(&topsrv.lock);

 	/*
 	 * Subscribe now if message contains a subscription,
 	 * otherwise send an empty response to complete connection handshaking
 	 */

 	subscriber_lock = subscriber->lock;
 	if (size)
 		subscr_subscribe((struct tipc_subscr *)data, subscriber);
 	else
 		tipc_send(subscriber->port_ref, 1, &msg_sect);

 	spin_unlock_bh(subscriber_lock);
 }

 int tipc_subscr_start(void)
 {
 	struct tipc_name_seq seq = {TIPC_TOP_SRV, TIPC_TOP_SRV, TIPC_TOP_SRV};
 	int res = -1;

 	memset(&topsrv, 0, sizeof (topsrv));
 	spin_lock_init(&topsrv.lock);
 	INIT_LIST_HEAD(&topsrv.subscriber_list);

 	spin_lock_bh(&topsrv.lock);
 	res = tipc_attach(&topsrv.user_ref, NULL, NULL);
 	if (res) {
 		spin_unlock_bh(&topsrv.lock);
 		return res;
 	}

  	res = tipc_createport(topsrv.user_ref,
  			      NULL,
  			      TIPC_CRITICAL_IMPORTANCE,
  			      NULL,
  			      NULL,
  			      NULL,
  			      NULL,
  			      subscr_named_msg_event,
  			      NULL,
  			      NULL,
  			      &topsrv.setup_port);
  	if (res)
 		goto failed;

  	res = tipc_nametbl_publish_rsv(topsrv.setup_port, TIPC_NODE_SCOPE, &seq);
  	if (res)
 		goto failed;

 	spin_unlock_bh(&topsrv.lock);
 	return 0;

 failed:
 	err("Failed to create subscription service\n");
 	tipc_detach(topsrv.user_ref);
 	topsrv.user_ref = 0;
 	spin_unlock_bh(&topsrv.lock);
 	return res;
 }

 void tipc_subscr_stop(void)
 {
 	struct subscriber *subscriber;
 	struct subscriber *subscriber_temp;
 	spinlock_t *subscriber_lock;

 	if (topsrv.user_ref) {
 		tipc_deleteport(topsrv.setup_port);
 		list_for_each_entry_safe(subscriber, subscriber_temp,
 					 &topsrv.subscriber_list,
 					 subscriber_list) {
 			tipc_ref_lock(subscriber->ref);
 			subscriber_lock = subscriber->lock;
 			subscr_terminate(subscriber);
 			spin_unlock_bh(subscriber_lock);
 		}
 		tipc_detach(topsrv.user_ref);
 		topsrv.user_ref = 0;
 	}
 }


 int tipc_ispublished(struct tipc_name const *name)
 {
 	u32 domain = 0;

 	return(tipc_nametbl_translate(name->type, name->instance,&domain) != 0);
 }
	/*
	* net/tipc/subscr.c: TIPC subscription service
	*
	* Copyright (c) 2000-2006, Ericsson AB
	* Copyright (c) 2005, 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 "dbg.h"
	#include "subscr.h"
	#include "name_table.h"
	#include "ref.h"

	/**
	* struct subscriber - TIPC network topology subscriber
	* @ref: object reference to subscriber object itself
	* @lock: pointer to spinlock controlling access to subscriber object
	* @subscriber_list: adjacent subscribers in top. server's list of subscribers
	* @subscription_list: list of subscription objects for this subscriber
	* @port_ref: object reference to port used to communicate with subscriber
	* @swap: indicates if subscriber uses opposite endianness in its messages
	*/

	struct subscriber {
	u32 ref;
	spinlock_t *lock;
	struct list_head subscriber_list;
	struct list_head subscription_list;
	u32 port_ref;
	int swap;
	};

	/**
	* struct top_srv - TIPC network topology subscription service
	* @user_ref: TIPC userid of subscription service
	* @setup_port: reference to TIPC port that handles subscription requests
	* @subscription_count: number of active subscriptions (not subscribers!)
	* @subscriber_list: list of ports subscribing to service
	* @lock: spinlock govering access to subscriber list
	*/

	struct top_srv {
	u32 user_ref;
	u32 setup_port;
	atomic_t subscription_count;
	struct list_head subscriber_list;
	spinlock_t lock;
	};

	static struct top_srv topsrv = { 0 };

	/**
	* 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)
	{
	char c = (char )&in;

	return swap ? ((c[3] << 3) + (c[2] << 2) + (c[1] << 1) + c[0]) : in;
	}

	/**
	* subscr_send_event - send a message containing a tipc_event to the subscriber
	*/

	static void subscr_send_event(struct subscription *sub,
	u32 found_lower,
	u32 found_upper,
	u32 event,
	u32 port_ref,
	u32 node)
	{
	struct iovec msg_sect;

	msg_sect.iov_base = (void *)&sub->evt;
	msg_sect.iov_len = sizeof(struct tipc_event);

	sub->evt.event = htohl(event, sub->owner->swap);
	sub->evt.found_lower = htohl(found_lower, sub->owner->swap);
	sub->evt.found_upper = htohl(found_upper, sub->owner->swap);
	sub->evt.port.ref = htohl(port_ref, sub->owner->swap);
	sub->evt.port.node = htohl(node, sub->owner->swap);
	tipc_send(sub->owner->port_ref, 1, &msg_sect);
	}

	/**
	* tipc_subscr_overlap - test for subscription overlap with the given values
	*
	* Returns 1 if there is overlap, otherwise 0.
	*/

	int tipc_subscr_overlap(struct 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 subscription *sub,
	u32 found_lower,
	u32 found_upper,
	u32 event,
	u32 port_ref,
	u32 node,
	int must)
	{
	dbg("Rep overlap %u:%u,%u<->%u,%u\n", sub->seq.type, sub->seq.lower,
	sub->seq.upper, found_lower, found_upper);
	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);
	}

	/**
	* subscr_timeout - subscription timeout has occurred
	*/

	static void subscr_timeout(struct subscription *sub)
	{
	struct subscriber *subscriber;
	u32 subscriber_ref;

	/* Validate subscriber reference (in case subscriber is terminating) */

	subscriber_ref = sub->owner->ref;
	subscriber = (struct subscriber *)tipc_ref_lock(subscriber_ref);
	if (subscriber == NULL)
	return;

	/* Validate timeout (in case subscription is being cancelled) */

	if (sub->timeout == TIPC_WAIT_FOREVER) {
	tipc_ref_unlock(subscriber_ref);
	return;
	}

	/* Unlink subscription from name table */

	tipc_nametbl_unsubscribe(sub);

	/* Notify subscriber of timeout, then unlink subscription */

	subscr_send_event(sub,
	sub->evt.s.seq.lower,
	sub->evt.s.seq.upper,
	TIPC_SUBSCR_TIMEOUT,
	0,
	0);
	list_del(&sub->subscription_list);

	/* Now destroy subscription */

	tipc_ref_unlock(subscriber_ref);
	k_term_timer(&sub->timer);
	kfree(sub);
	atomic_dec(&topsrv.subscription_count);
	}

	/**
	* subscr_del - delete a subscription within a subscription list
	*
	* Called with subscriber locked.
	*/

	static void subscr_del(struct subscription *sub)
	{
	tipc_nametbl_unsubscribe(sub);
	list_del(&sub->subscription_list);
	kfree(sub);
	atomic_dec(&topsrv.subscription_count);
	}

	/**
	* subscr_terminate - terminate communication with a subscriber
	*
	* Called with subscriber locked. Routine must temporarily release this lock
	* to enable subscription timeout routine(s) to finish without deadlocking;
	* the lock is then reclaimed to allow caller to release it upon return.
	* (This should work even in the unlikely event some other thread creates
	* a new object reference in the interim that uses this lock; this routine will
	* simply wait for it to be released, then claim it.)
	*/

	static void subscr_terminate(struct subscriber *subscriber)
	{
	struct subscription *sub;
	struct subscription *sub_temp;

	/* Invalidate subscriber reference */

	tipc_ref_discard(subscriber->ref);
	spin_unlock_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) {
	k_cancel_timer(&sub->timer);
	k_term_timer(&sub->timer);
	}
	dbg("Term: Removing sub %u,%u,%u from subscriber %x list\n",
	sub->seq.type, sub->seq.lower, sub->seq.upper, subscriber);
	subscr_del(sub);
	}

	/* Sever connection to subscriber */

	tipc_shutdown(subscriber->port_ref);
	tipc_deleteport(subscriber->port_ref);

	/* Remove subscriber from topology server's subscriber list */

	spin_lock_bh(&topsrv.lock);
	list_del(&subscriber->subscriber_list);
	spin_unlock_bh(&topsrv.lock);

	/* Now destroy subscriber */

	spin_lock_bh(subscriber->lock);
	kfree(subscriber);
	}

	/**
	* subscr_cancel - handle subscription cancellation request
	*
	* Called with subscriber locked. Routine must temporarily release this 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 subscriber *subscriber)
	{
	struct subscription *sub;
	struct 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);
	k_cancel_timer(&sub->timer);
	k_term_timer(&sub->timer);
	spin_lock_bh(subscriber->lock);
	}
	dbg("Cancel: removing sub %u,%u,%u from subscriber %x list\n",
	sub->seq.type, sub->seq.lower, sub->seq.upper, subscriber);
	subscr_del(sub);
	}

	/**
	* subscr_subscribe - create subscription for subscriber
	*
	* Called with subscriber locked
	*/

	static void subscr_subscribe(struct tipc_subscr *s,
	struct subscriber *subscriber)
	{
	struct subscription *sub;

	/* Determine/update subscriber's endianness */

	if (s->filter & (TIPC_SUB_PORTS \| TIPC_SUB_SERVICE))
	subscriber->swap = 0;
	else
	subscriber->swap = 1;

	/* Detect & process a subscription cancellation request */

	if (s->filter & htohl(TIPC_SUB_CANCEL, subscriber->swap)) {
	s->filter &= ~htohl(TIPC_SUB_CANCEL, subscriber->swap);
	subscr_cancel(s, subscriber);
	return;
	}

	/* Refuse subscription if global limit exceeded */

	if (atomic_read(&topsrv.subscription_count) >= tipc_max_subscriptions) {
	warn("Subscription rejected, subscription limit reached (%u)\n",
	tipc_max_subscriptions);
	subscr_terminate(subscriber);
	return;
	}

	/* Allocate subscription object */

	sub = kmalloc(sizeof(*sub), GFP_ATOMIC);
	if (!sub) {
	warn("Subscription rejected, no memory\n");
	subscr_terminate(subscriber);
	return;
	}

	/* Initialize subscription object */

	memset(sub, 0, sizeof(*sub));
	sub->seq.type = htohl(s->seq.type, subscriber->swap);
	sub->seq.lower = htohl(s->seq.lower, subscriber->swap);
	sub->seq.upper = htohl(s->seq.upper, subscriber->swap);
	sub->timeout = htohl(s->timeout, subscriber->swap);
	sub->filter = htohl(s->filter, subscriber->swap);
	if ((!(sub->filter & TIPC_SUB_PORTS)
	== !(sub->filter & TIPC_SUB_SERVICE))
	\|\| (sub->seq.lower > sub->seq.upper)) {
	warn("Subscription rejected, illegal request\n");
	kfree(sub);
	subscr_terminate(subscriber);
	return;
	}
	memcpy(&sub->evt.s, s, sizeof(struct tipc_subscr));
	INIT_LIST_HEAD(&sub->subscription_list);
	INIT_LIST_HEAD(&sub->nameseq_list);
	list_add(&sub->subscription_list, &subscriber->subscription_list);
	atomic_inc(&topsrv.subscription_count);
	if (sub->timeout != TIPC_WAIT_FOREVER) {
	k_init_timer(&sub->timer,
	(Handler)subscr_timeout, (unsigned long)sub);
	k_start_timer(&sub->timer, sub->timeout);
	}
	sub->owner = subscriber;
	tipc_nametbl_subscribe(sub);
	}

	/**
	* subscr_conn_shutdown_event - handle termination request from subscriber
	*/

	static void subscr_conn_shutdown_event(void *usr_handle,
	u32 portref,
	struct sk_buff **buf,
	unsigned char const *data,
	unsigned int size,
	int reason)
	{
	struct subscriber *subscriber;
	spinlock_t *subscriber_lock;

	subscriber = tipc_ref_lock((u32)(unsigned long)usr_handle);
	if (subscriber == NULL)
	return;

	subscriber_lock = subscriber->lock;
	subscr_terminate(subscriber);
	spin_unlock_bh(subscriber_lock);
	}

	/**
	* subscr_conn_msg_event - handle new subscription request from subscriber
	*/

	static void subscr_conn_msg_event(void *usr_handle,
	u32 port_ref,
	struct sk_buff **buf,
	const unchar *data,
	u32 size)
	{
	struct subscriber *subscriber;
	spinlock_t *subscriber_lock;

	subscriber = tipc_ref_lock((u32)(unsigned long)usr_handle);
	if (subscriber == NULL)
	return;

	subscriber_lock = subscriber->lock;
	if (size != sizeof(struct tipc_subscr))
	subscr_terminate(subscriber);
	else
	subscr_subscribe((struct tipc_subscr *)data, subscriber);

	spin_unlock_bh(subscriber_lock);
	}

	/**
	* subscr_named_msg_event - handle request to establish a new subscriber
	*/

	static void subscr_named_msg_event(void *usr_handle,
	u32 port_ref,
	struct sk_buff **buf,
	const unchar *data,
	u32 size,
	u32 importance,
	struct tipc_portid const *orig,
	struct tipc_name_seq const *dest)
	{
	struct subscriber *subscriber;
	struct iovec msg_sect = {NULL, 0};
	spinlock_t *subscriber_lock;

	dbg("subscr_named_msg_event: orig = %x own = %x,\n",
	orig->node, tipc_own_addr);
	if (size && (size != sizeof(struct tipc_subscr))) {
	warn("Subscriber rejected, invalid subscription size\n");
	return;
	}

	/* Create subscriber object */

	subscriber = kzalloc(sizeof(struct subscriber), GFP_ATOMIC);
	if (subscriber == NULL) {
	warn("Subscriber rejected, no memory\n");
	return;
	}
	INIT_LIST_HEAD(&subscriber->subscription_list);
	INIT_LIST_HEAD(&subscriber->subscriber_list);
	subscriber->ref = tipc_ref_acquire(subscriber, &subscriber->lock);
	if (subscriber->ref == 0) {
	warn("Subscriber rejected, reference table exhausted\n");
	kfree(subscriber);
	return;
	}

	/* Establish a connection to subscriber */

	tipc_createport(topsrv.user_ref,
	(void *)(unsigned long)subscriber->ref,
	importance,
	NULL,
	NULL,
	subscr_conn_shutdown_event,
	NULL,
	NULL,
	subscr_conn_msg_event,
	NULL,
	&subscriber->port_ref);
	if (subscriber->port_ref == 0) {
	warn("Subscriber rejected, unable to create port\n");
	tipc_ref_discard(subscriber->ref);
	kfree(subscriber);
	return;
	}
	tipc_connect2port(subscriber->port_ref, orig);


	/* Add subscriber to topology server's subscriber list */

	tipc_ref_lock(subscriber->ref);
	spin_lock_bh(&topsrv.lock);
	list_add(&subscriber->subscriber_list, &topsrv.subscriber_list);
	spin_unlock_bh(&topsrv.lock);

	/*
	* Subscribe now if message contains a subscription,
	* otherwise send an empty response to complete connection handshaking
	*/

	subscriber_lock = subscriber->lock;
	if (size)
	subscr_subscribe((struct tipc_subscr *)data, subscriber);
	else
	tipc_send(subscriber->port_ref, 1, &msg_sect);

	spin_unlock_bh(subscriber_lock);
	}

	int tipc_subscr_start(void)
	{
	struct tipc_name_seq seq = {TIPC_TOP_SRV, TIPC_TOP_SRV, TIPC_TOP_SRV};
	int res = -1;

	memset(&topsrv, 0, sizeof (topsrv));
	spin_lock_init(&topsrv.lock);
	INIT_LIST_HEAD(&topsrv.subscriber_list);

	spin_lock_bh(&topsrv.lock);
	res = tipc_attach(&topsrv.user_ref, NULL, NULL);
	if (res) {
	spin_unlock_bh(&topsrv.lock);
	return res;
	}

	res = tipc_createport(topsrv.user_ref,
	NULL,
	TIPC_CRITICAL_IMPORTANCE,
	NULL,
	NULL,
	NULL,
	NULL,
	subscr_named_msg_event,
	NULL,
	NULL,
	&topsrv.setup_port);
	if (res)
	goto failed;

	res = tipc_nametbl_publish_rsv(topsrv.setup_port, TIPC_NODE_SCOPE, &seq);
	if (res)
	goto failed;

	spin_unlock_bh(&topsrv.lock);
	return 0;

	failed:
	err("Failed to create subscription service\n");
	tipc_detach(topsrv.user_ref);
	topsrv.user_ref = 0;
	spin_unlock_bh(&topsrv.lock);
	return res;
	}

	void tipc_subscr_stop(void)
	{
	struct subscriber *subscriber;
	struct subscriber *subscriber_temp;
	spinlock_t *subscriber_lock;

	if (topsrv.user_ref) {
	tipc_deleteport(topsrv.setup_port);
	list_for_each_entry_safe(subscriber, subscriber_temp,
	&topsrv.subscriber_list,
	subscriber_list) {
	tipc_ref_lock(subscriber->ref);
	subscriber_lock = subscriber->lock;
	subscr_terminate(subscriber);
	spin_unlock_bh(subscriber_lock);
	}
	tipc_detach(topsrv.user_ref);
	topsrv.user_ref = 0;
	}
	}


	int tipc_ispublished(struct tipc_name const *name)
	{
	u32 domain = 0;

	return(tipc_nametbl_translate(name->type, name->instance,&domain) != 0);
	}