linux/net/tipc/subscr.h
Tuong Lien 88690b1079 tipc: fix failed service subscription deletion
When a service subscription is expired or canceled by user, it needs to
be deleted from the subscription list, so that new subscriptions can be
registered (max = 65535 per net). However, there are two issues in code
that can cause such an unused subscription to persist:

1) The 'tipc_conn_delete_sub()' has a loop on the subscription list but
it makes a break shortly when the 1st subscription differs from the one
specified, so the subscription will not be deleted.

2) In case a subscription is canceled, the code to remove the
'TIPC_SUB_CANCEL' flag from the subscription filter does not work if it
is a local subscription (i.e. the little endian isn't involved). So, it
will be no matches when looking for the subscription to delete later.

The subscription(s) will be removed eventually when the user terminates
its topology connection but that could be a long time later. Meanwhile,
the number of available subscriptions may be exhausted.

This commit fixes the two issues above, so as needed a subscription can
be deleted correctly.

Acked-by: Ying Xue <ying.xue@windriver.com>
Acked-by: Jon Maloy <jmaloy@redhat.com>
Signed-off-by: Tuong Lien <tuong.t.lien@dektech.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-05-13 12:33:19 -07:00

120 lines
4.4 KiB
C

/*
* net/tipc/subscr.h: Include file for TIPC network topology service
*
* Copyright (c) 2003-2017, Ericsson AB
* Copyright (c) 2005-2007, 2012-2013, 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.
*/
#ifndef _TIPC_SUBSCR_H
#define _TIPC_SUBSCR_H
#include "topsrv.h"
#define TIPC_MAX_SUBSCR 65535
#define TIPC_MAX_PUBL 65535
struct tipc_subscription;
struct tipc_conn;
/**
* struct tipc_subscription - TIPC network topology subscription object
* @subscriber: pointer to its subscriber
* @seq: name sequence associated with subscription
* @timer: timer governing subscription duration (optional)
* @nameseq_list: adjacent subscriptions in name sequence's subscription list
* @sub_list: adjacent subscriptions in subscriber's subscription list
* @evt: template for events generated by subscription
*/
struct tipc_subscription {
struct kref kref;
struct net *net;
struct timer_list timer;
struct list_head service_list;
struct list_head sub_list;
struct tipc_event evt;
int conid;
bool inactive;
spinlock_t lock; /* serialize up/down and timer events */
};
struct tipc_subscription *tipc_sub_subscribe(struct net *net,
struct tipc_subscr *s,
int conid);
void tipc_sub_unsubscribe(struct tipc_subscription *sub);
int tipc_sub_check_overlap(struct tipc_name_seq *seq, u32 found_lower,
u32 found_upper);
void tipc_sub_report_overlap(struct tipc_subscription *sub,
u32 found_lower, u32 found_upper,
u32 event, u32 port, u32 node,
u32 scope, int must);
int __net_init tipc_topsrv_init_net(struct net *net);
void __net_exit tipc_topsrv_exit_net(struct net *net);
void tipc_sub_put(struct tipc_subscription *subscription);
void tipc_sub_get(struct tipc_subscription *subscription);
#define TIPC_FILTER_MASK (TIPC_SUB_PORTS | TIPC_SUB_SERVICE | TIPC_SUB_CANCEL)
/* tipc_sub_read - return field_ of struct sub_ in host endian format
*/
#define tipc_sub_read(sub_, field_) \
({ \
struct tipc_subscr *sub__ = sub_; \
u32 val__ = (sub__)->field_; \
int swap_ = !((sub__)->filter & TIPC_FILTER_MASK); \
(swap_ ? swab32(val__) : val__); \
})
/* tipc_sub_write - write val_ to field_ of struct sub_ in user endian format
*/
#define tipc_sub_write(sub_, field_, val_) \
({ \
struct tipc_subscr *sub__ = sub_; \
u32 val__ = val_; \
int swap_ = !((sub__)->filter & TIPC_FILTER_MASK); \
(sub__)->field_ = swap_ ? swab32(val__) : val__; \
})
/* tipc_evt_write - write val_ to field_ of struct evt_ in user endian format
*/
#define tipc_evt_write(evt_, field_, val_) \
({ \
struct tipc_event *evt__ = evt_; \
u32 val__ = val_; \
int swap_ = !((evt__)->s.filter & (TIPC_FILTER_MASK)); \
(evt__)->field_ = swap_ ? swab32(val__) : val__; \
})
#endif