![Allan Stephens](/assets/img/avatar_default.png)
Streamlines the logic that prevents an application from binding a reserved TIPC name type to a port by moving the check to the code that handles a socket bind() operation. This allows internal TIPC subsystems to bind a reserved name without having to set an atomic flag to gain permission to use such a name. (This simplification is now possible due to the elimination of support for TIPC's native API.) Signed-off-by: Allan Stephens <allan.stephens@windriver.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
589 lines
16 KiB
C
589 lines
16 KiB
C
/*
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* net/tipc/subscr.c: TIPC network topology service
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*
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* Copyright (c) 2000-2006, Ericsson AB
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* Copyright (c) 2005-2007, 2010-2011, Wind River Systems
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the names of the copyright holders nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* Alternatively, this software may be distributed under the terms of the
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* GNU General Public License ("GPL") version 2 as published by the Free
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* Software Foundation.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "core.h"
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#include "name_table.h"
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#include "port.h"
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#include "subscr.h"
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/**
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* struct tipc_subscriber - TIPC network topology subscriber
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* @port_ref: object reference to server port connecting to subscriber
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* @lock: pointer to spinlock controlling access to subscriber's server port
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* @subscriber_list: adjacent subscribers in top. server's list of subscribers
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* @subscription_list: list of subscription objects for this subscriber
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*/
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struct tipc_subscriber {
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u32 port_ref;
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spinlock_t *lock;
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struct list_head subscriber_list;
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struct list_head subscription_list;
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};
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/**
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* struct top_srv - TIPC network topology subscription service
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* @user_ref: TIPC userid of subscription service
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* @setup_port: reference to TIPC port that handles subscription requests
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* @subscription_count: number of active subscriptions (not subscribers!)
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* @subscriber_list: list of ports subscribing to service
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* @lock: spinlock govering access to subscriber list
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*/
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struct top_srv {
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u32 setup_port;
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atomic_t subscription_count;
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struct list_head subscriber_list;
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spinlock_t lock;
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};
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static struct top_srv topsrv;
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/**
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* htohl - convert value to endianness used by destination
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* @in: value to convert
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* @swap: non-zero if endianness must be reversed
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*
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* Returns converted value
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*/
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static u32 htohl(u32 in, int swap)
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{
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return swap ? swab32(in) : in;
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}
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/**
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* subscr_send_event - send a message containing a tipc_event to the subscriber
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*
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* Note: Must not hold subscriber's server port lock, since tipc_send() will
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* try to take the lock if the message is rejected and returned!
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*/
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static void subscr_send_event(struct tipc_subscription *sub,
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u32 found_lower,
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u32 found_upper,
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u32 event,
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u32 port_ref,
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u32 node)
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{
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struct iovec msg_sect;
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msg_sect.iov_base = (void *)&sub->evt;
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msg_sect.iov_len = sizeof(struct tipc_event);
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sub->evt.event = htohl(event, sub->swap);
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sub->evt.found_lower = htohl(found_lower, sub->swap);
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sub->evt.found_upper = htohl(found_upper, sub->swap);
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sub->evt.port.ref = htohl(port_ref, sub->swap);
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sub->evt.port.node = htohl(node, sub->swap);
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tipc_send(sub->server_ref, 1, &msg_sect, msg_sect.iov_len);
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}
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/**
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* tipc_subscr_overlap - test for subscription overlap with the given values
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*
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* Returns 1 if there is overlap, otherwise 0.
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*/
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int tipc_subscr_overlap(struct tipc_subscription *sub,
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u32 found_lower,
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u32 found_upper)
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{
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if (found_lower < sub->seq.lower)
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found_lower = sub->seq.lower;
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if (found_upper > sub->seq.upper)
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found_upper = sub->seq.upper;
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if (found_lower > found_upper)
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return 0;
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return 1;
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}
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/**
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* tipc_subscr_report_overlap - issue event if there is subscription overlap
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*
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* Protected by nameseq.lock in name_table.c
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*/
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void tipc_subscr_report_overlap(struct tipc_subscription *sub,
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u32 found_lower,
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u32 found_upper,
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u32 event,
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u32 port_ref,
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u32 node,
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int must)
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{
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if (!tipc_subscr_overlap(sub, found_lower, found_upper))
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return;
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if (!must && !(sub->filter & TIPC_SUB_PORTS))
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return;
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subscr_send_event(sub, found_lower, found_upper, event, port_ref, node);
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}
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/**
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* subscr_timeout - subscription timeout has occurred
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*/
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static void subscr_timeout(struct tipc_subscription *sub)
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{
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struct tipc_port *server_port;
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/* Validate server port reference (in case subscriber is terminating) */
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server_port = tipc_port_lock(sub->server_ref);
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if (server_port == NULL)
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return;
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/* Validate timeout (in case subscription is being cancelled) */
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if (sub->timeout == TIPC_WAIT_FOREVER) {
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tipc_port_unlock(server_port);
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return;
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}
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/* Unlink subscription from name table */
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tipc_nametbl_unsubscribe(sub);
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/* Unlink subscription from subscriber */
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list_del(&sub->subscription_list);
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/* Release subscriber's server port */
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tipc_port_unlock(server_port);
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/* Notify subscriber of timeout */
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subscr_send_event(sub, sub->evt.s.seq.lower, sub->evt.s.seq.upper,
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TIPC_SUBSCR_TIMEOUT, 0, 0);
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/* Now destroy subscription */
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k_term_timer(&sub->timer);
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kfree(sub);
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atomic_dec(&topsrv.subscription_count);
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}
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/**
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* subscr_del - delete a subscription within a subscription list
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*
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* Called with subscriber port locked.
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*/
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static void subscr_del(struct tipc_subscription *sub)
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{
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tipc_nametbl_unsubscribe(sub);
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list_del(&sub->subscription_list);
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kfree(sub);
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atomic_dec(&topsrv.subscription_count);
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}
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/**
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* subscr_terminate - terminate communication with a subscriber
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*
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* Called with subscriber port locked. Routine must temporarily release lock
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* to enable subscription timeout routine(s) to finish without deadlocking;
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* the lock is then reclaimed to allow caller to release it upon return.
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* (This should work even in the unlikely event some other thread creates
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* a new object reference in the interim that uses this lock; this routine will
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* simply wait for it to be released, then claim it.)
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*/
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static void subscr_terminate(struct tipc_subscriber *subscriber)
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{
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u32 port_ref;
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struct tipc_subscription *sub;
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struct tipc_subscription *sub_temp;
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/* Invalidate subscriber reference */
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port_ref = subscriber->port_ref;
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subscriber->port_ref = 0;
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spin_unlock_bh(subscriber->lock);
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/* Sever connection to subscriber */
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tipc_shutdown(port_ref);
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tipc_deleteport(port_ref);
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/* Destroy any existing subscriptions for subscriber */
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list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
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subscription_list) {
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if (sub->timeout != TIPC_WAIT_FOREVER) {
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k_cancel_timer(&sub->timer);
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k_term_timer(&sub->timer);
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}
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subscr_del(sub);
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}
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/* Remove subscriber from topology server's subscriber list */
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spin_lock_bh(&topsrv.lock);
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list_del(&subscriber->subscriber_list);
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spin_unlock_bh(&topsrv.lock);
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/* Reclaim subscriber lock */
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spin_lock_bh(subscriber->lock);
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/* Now destroy subscriber */
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kfree(subscriber);
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}
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/**
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* subscr_cancel - handle subscription cancellation request
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*
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* Called with subscriber port locked. Routine must temporarily release lock
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* to enable the subscription timeout routine to finish without deadlocking;
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* the lock is then reclaimed to allow caller to release it upon return.
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*
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* Note that fields of 's' use subscriber's endianness!
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*/
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static void subscr_cancel(struct tipc_subscr *s,
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struct tipc_subscriber *subscriber)
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{
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struct tipc_subscription *sub;
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struct tipc_subscription *sub_temp;
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int found = 0;
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/* Find first matching subscription, exit if not found */
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list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
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subscription_list) {
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if (!memcmp(s, &sub->evt.s, sizeof(struct tipc_subscr))) {
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found = 1;
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break;
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}
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}
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if (!found)
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return;
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/* Cancel subscription timer (if used), then delete subscription */
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if (sub->timeout != TIPC_WAIT_FOREVER) {
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sub->timeout = TIPC_WAIT_FOREVER;
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spin_unlock_bh(subscriber->lock);
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k_cancel_timer(&sub->timer);
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k_term_timer(&sub->timer);
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spin_lock_bh(subscriber->lock);
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}
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subscr_del(sub);
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}
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/**
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* subscr_subscribe - create subscription for subscriber
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*
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* Called with subscriber port locked.
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*/
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static struct tipc_subscription *subscr_subscribe(struct tipc_subscr *s,
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struct tipc_subscriber *subscriber)
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{
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struct tipc_subscription *sub;
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int swap;
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/* Determine subscriber's endianness */
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swap = !(s->filter & (TIPC_SUB_PORTS | TIPC_SUB_SERVICE));
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/* Detect & process a subscription cancellation request */
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if (s->filter & htohl(TIPC_SUB_CANCEL, swap)) {
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s->filter &= ~htohl(TIPC_SUB_CANCEL, swap);
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subscr_cancel(s, subscriber);
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return NULL;
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}
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/* Refuse subscription if global limit exceeded */
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if (atomic_read(&topsrv.subscription_count) >= tipc_max_subscriptions) {
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warn("Subscription rejected, subscription limit reached (%u)\n",
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tipc_max_subscriptions);
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subscr_terminate(subscriber);
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return NULL;
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}
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/* Allocate subscription object */
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sub = kmalloc(sizeof(*sub), GFP_ATOMIC);
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if (!sub) {
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warn("Subscription rejected, no memory\n");
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subscr_terminate(subscriber);
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return NULL;
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}
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/* Initialize subscription object */
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sub->seq.type = htohl(s->seq.type, swap);
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sub->seq.lower = htohl(s->seq.lower, swap);
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sub->seq.upper = htohl(s->seq.upper, swap);
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sub->timeout = htohl(s->timeout, swap);
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sub->filter = htohl(s->filter, swap);
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if ((!(sub->filter & TIPC_SUB_PORTS) ==
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!(sub->filter & TIPC_SUB_SERVICE)) ||
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(sub->seq.lower > sub->seq.upper)) {
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warn("Subscription rejected, illegal request\n");
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kfree(sub);
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subscr_terminate(subscriber);
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return NULL;
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}
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INIT_LIST_HEAD(&sub->nameseq_list);
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list_add(&sub->subscription_list, &subscriber->subscription_list);
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sub->server_ref = subscriber->port_ref;
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sub->swap = swap;
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memcpy(&sub->evt.s, s, sizeof(struct tipc_subscr));
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atomic_inc(&topsrv.subscription_count);
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if (sub->timeout != TIPC_WAIT_FOREVER) {
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k_init_timer(&sub->timer,
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(Handler)subscr_timeout, (unsigned long)sub);
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k_start_timer(&sub->timer, sub->timeout);
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}
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return sub;
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}
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/**
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* subscr_conn_shutdown_event - handle termination request from subscriber
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*
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* Called with subscriber's server port unlocked.
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*/
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static void subscr_conn_shutdown_event(void *usr_handle,
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u32 port_ref,
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struct sk_buff **buf,
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unsigned char const *data,
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unsigned int size,
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int reason)
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{
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struct tipc_subscriber *subscriber = usr_handle;
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spinlock_t *subscriber_lock;
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if (tipc_port_lock(port_ref) == NULL)
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return;
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subscriber_lock = subscriber->lock;
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subscr_terminate(subscriber);
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spin_unlock_bh(subscriber_lock);
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}
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/**
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* subscr_conn_msg_event - handle new subscription request from subscriber
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*
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* Called with subscriber's server port unlocked.
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*/
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static void subscr_conn_msg_event(void *usr_handle,
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u32 port_ref,
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struct sk_buff **buf,
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const unchar *data,
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u32 size)
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{
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struct tipc_subscriber *subscriber = usr_handle;
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spinlock_t *subscriber_lock;
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struct tipc_subscription *sub;
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/*
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* Lock subscriber's server port (& make a local copy of lock pointer,
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* in case subscriber is deleted while processing subscription request)
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*/
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if (tipc_port_lock(port_ref) == NULL)
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return;
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subscriber_lock = subscriber->lock;
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if (size != sizeof(struct tipc_subscr)) {
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subscr_terminate(subscriber);
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spin_unlock_bh(subscriber_lock);
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} else {
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sub = subscr_subscribe((struct tipc_subscr *)data, subscriber);
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spin_unlock_bh(subscriber_lock);
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if (sub != NULL) {
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/*
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* We must release the server port lock before adding a
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* subscription to the name table since TIPC needs to be
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* able to (re)acquire the port lock if an event message
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* issued by the subscription process is rejected and
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* returned. The subscription cannot be deleted while
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* it is being added to the name table because:
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* a) the single-threading of the native API port code
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* ensures the subscription cannot be cancelled and
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* the subscriber connection cannot be broken, and
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* b) the name table lock ensures the subscription
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* timeout code cannot delete the subscription,
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* so the subscription object is still protected.
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*/
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tipc_nametbl_subscribe(sub);
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}
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}
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}
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/**
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* subscr_named_msg_event - handle request to establish a new subscriber
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*/
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static void subscr_named_msg_event(void *usr_handle,
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u32 port_ref,
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struct sk_buff **buf,
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const unchar *data,
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u32 size,
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u32 importance,
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struct tipc_portid const *orig,
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struct tipc_name_seq const *dest)
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{
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struct tipc_subscriber *subscriber;
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u32 server_port_ref;
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/* Create subscriber object */
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subscriber = kzalloc(sizeof(struct tipc_subscriber), GFP_ATOMIC);
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if (subscriber == NULL) {
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warn("Subscriber rejected, no memory\n");
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return;
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}
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INIT_LIST_HEAD(&subscriber->subscription_list);
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INIT_LIST_HEAD(&subscriber->subscriber_list);
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/* Create server port & establish connection to subscriber */
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tipc_createport(subscriber,
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importance,
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NULL,
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NULL,
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subscr_conn_shutdown_event,
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NULL,
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NULL,
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subscr_conn_msg_event,
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NULL,
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&subscriber->port_ref);
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if (subscriber->port_ref == 0) {
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warn("Subscriber rejected, unable to create port\n");
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kfree(subscriber);
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return;
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}
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tipc_connect2port(subscriber->port_ref, orig);
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/* Lock server port (& save lock address for future use) */
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subscriber->lock = tipc_port_lock(subscriber->port_ref)->lock;
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/* Add subscriber to topology server's subscriber list */
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spin_lock_bh(&topsrv.lock);
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list_add(&subscriber->subscriber_list, &topsrv.subscriber_list);
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spin_unlock_bh(&topsrv.lock);
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/* Unlock server port */
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server_port_ref = subscriber->port_ref;
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spin_unlock_bh(subscriber->lock);
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/* Send an ACK- to complete connection handshaking */
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tipc_send(server_port_ref, 0, NULL, 0);
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/* Handle optional subscription request */
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if (size != 0) {
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subscr_conn_msg_event(subscriber, server_port_ref,
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buf, data, size);
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}
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}
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int tipc_subscr_start(void)
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{
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struct tipc_name_seq seq = {TIPC_TOP_SRV, TIPC_TOP_SRV, TIPC_TOP_SRV};
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int res;
|
|
|
|
memset(&topsrv, 0, sizeof(topsrv));
|
|
spin_lock_init(&topsrv.lock);
|
|
INIT_LIST_HEAD(&topsrv.subscriber_list);
|
|
|
|
res = tipc_createport(NULL,
|
|
TIPC_CRITICAL_IMPORTANCE,
|
|
NULL,
|
|
NULL,
|
|
NULL,
|
|
NULL,
|
|
subscr_named_msg_event,
|
|
NULL,
|
|
NULL,
|
|
&topsrv.setup_port);
|
|
if (res)
|
|
goto failed;
|
|
|
|
res = tipc_publish(topsrv.setup_port, TIPC_NODE_SCOPE, &seq);
|
|
if (res) {
|
|
tipc_deleteport(topsrv.setup_port);
|
|
topsrv.setup_port = 0;
|
|
goto failed;
|
|
}
|
|
|
|
return 0;
|
|
|
|
failed:
|
|
err("Failed to create subscription service\n");
|
|
return res;
|
|
}
|
|
|
|
void tipc_subscr_stop(void)
|
|
{
|
|
struct tipc_subscriber *subscriber;
|
|
struct tipc_subscriber *subscriber_temp;
|
|
spinlock_t *subscriber_lock;
|
|
|
|
if (topsrv.setup_port) {
|
|
tipc_deleteport(topsrv.setup_port);
|
|
topsrv.setup_port = 0;
|
|
|
|
list_for_each_entry_safe(subscriber, subscriber_temp,
|
|
&topsrv.subscriber_list,
|
|
subscriber_list) {
|
|
subscriber_lock = subscriber->lock;
|
|
spin_lock_bh(subscriber_lock);
|
|
subscr_terminate(subscriber);
|
|
spin_unlock_bh(subscriber_lock);
|
|
}
|
|
}
|
|
}
|