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![Ying Xue](/assets/img/avatar_default.png)
When a topology server accepts a connection request from its client, it allocates a connection instance and a tipc_subscriber structure object. The former is used to communicate with client, and the latter is often treated as a subscriber which manages all subscription events requested from a same client. When a topology server receives a request of subscribing name services from a client through the connection, it creates a tipc_subscription structure instance which is seen as a subscription recording what name services are subscribed. In order to manage all subscriptions from a same client, topology server links them into the subscrp_list of the subscriber. So subscriber and subscription completely represents different meanings respectively, but function names associated with them make us so confused that we are unable to easily tell which function is against subscriber and which is to subscription. So we want to eliminate the confusion by renaming them. Signed-off-by: Ying Xue <ying.xue@windriver.com> Reviewed-by: Jon Maloy <jon.maloy@ericson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
365 lines
11 KiB
C
365 lines
11 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, 2010-2013, 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 "subscr.h"
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/**
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* struct tipc_subscriber - TIPC network topology subscriber
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* @conid: connection identifier to server connecting to subscriber
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* @lock: control access to subscriber
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* @subscrp_list: list of subscription objects for this subscriber
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*/
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struct tipc_subscriber {
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int conid;
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spinlock_t lock;
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struct list_head subscrp_list;
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};
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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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static void tipc_subscrp_send_event(struct tipc_subscription *sub,
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u32 found_lower, u32 found_upper,
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u32 event, u32 port_ref, u32 node)
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{
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struct tipc_net *tn = net_generic(sub->net, tipc_net_id);
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struct tipc_subscriber *subscriber = sub->subscriber;
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struct kvec 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_conn_sendmsg(tn->topsrv, subscriber->conid, NULL,
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msg_sect.iov_base, msg_sect.iov_len);
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}
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/**
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* tipc_subscrp_check_overlap - test for subscription overlap with the
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* 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_subscrp_check_overlap(struct tipc_subscription *sub, 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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void tipc_subscrp_report_overlap(struct tipc_subscription *sub, u32 found_lower,
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u32 found_upper, u32 event, u32 port_ref,
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u32 node, int must)
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{
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if (!tipc_subscrp_check_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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tipc_subscrp_send_event(sub, found_lower, found_upper, event, port_ref,
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node);
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}
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static void tipc_subscrp_timeout(unsigned long data)
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{
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struct tipc_subscription *sub = (struct tipc_subscription *)data;
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struct tipc_subscriber *subscriber = sub->subscriber;
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struct tipc_net *tn = net_generic(sub->net, tipc_net_id);
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/* The spin lock per subscriber is used to protect its members */
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spin_lock_bh(&subscriber->lock);
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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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spin_unlock_bh(&subscriber->lock);
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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->subscrp_list);
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spin_unlock_bh(&subscriber->lock);
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/* Notify subscriber of timeout */
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tipc_subscrp_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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kfree(sub);
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atomic_dec(&tn->subscription_count);
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}
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static void tipc_subscrp_delete(struct tipc_subscription *sub)
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{
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struct tipc_net *tn = net_generic(sub->net, tipc_net_id);
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tipc_nametbl_unsubscribe(sub);
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list_del(&sub->subscrp_list);
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kfree(sub);
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atomic_dec(&tn->subscription_count);
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}
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static void tipc_subscrb_delete(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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spin_lock_bh(&subscriber->lock);
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/* Destroy any existing subscriptions for subscriber */
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list_for_each_entry_safe(sub, sub_temp, &subscriber->subscrp_list,
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subscrp_list) {
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if (sub->timeout != TIPC_WAIT_FOREVER) {
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spin_unlock_bh(&subscriber->lock);
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del_timer_sync(&sub->timer);
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spin_lock_bh(&subscriber->lock);
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}
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tipc_subscrp_delete(sub);
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}
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spin_unlock_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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* tipc_subscrp_cancel - handle subscription cancellation request
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*
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* Called with subscriber lock held. 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 tipc_subscrp_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->subscrp_list,
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subscrp_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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del_timer_sync(&sub->timer);
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spin_lock_bh(&subscriber->lock);
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}
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tipc_subscrp_delete(sub);
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}
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static int tipc_subscrp_create(struct net *net, struct tipc_subscr *s,
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struct tipc_subscriber *subscriber,
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struct tipc_subscription **sub_p)
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{
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struct tipc_net *tn = net_generic(net, tipc_net_id);
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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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tipc_subscrp_cancel(s, subscriber);
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return 0;
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}
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/* Refuse subscription if global limit exceeded */
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if (atomic_read(&tn->subscription_count) >= TIPC_MAX_SUBSCRIPTIONS) {
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pr_warn("Subscription rejected, limit reached (%u)\n",
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TIPC_MAX_SUBSCRIPTIONS);
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return -EINVAL;
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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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pr_warn("Subscription rejected, no memory\n");
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return -ENOMEM;
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}
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/* Initialize subscription object */
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sub->net = net;
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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 = msecs_to_jiffies(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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pr_warn("Subscription rejected, illegal request\n");
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kfree(sub);
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return -EINVAL;
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}
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list_add(&sub->subscrp_list, &subscriber->subscrp_list);
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sub->subscriber = subscriber;
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sub->swap = swap;
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memcpy(&sub->evt.s, s, sizeof(*s));
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atomic_inc(&tn->subscription_count);
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if (sub->timeout != TIPC_WAIT_FOREVER) {
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setup_timer(&sub->timer, tipc_subscrp_timeout,
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(unsigned long)sub);
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mod_timer(&sub->timer, jiffies + sub->timeout);
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}
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*sub_p = sub;
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return 0;
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}
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/* Handle one termination request for the subscriber */
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static void tipc_subscrb_shutdown_cb(int conid, void *usr_data)
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{
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tipc_subscrb_delete((struct tipc_subscriber *)usr_data);
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}
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/* Handle one request to create a new subscription for the subscriber */
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static void tipc_subscrb_rcv_cb(struct net *net, int conid,
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struct sockaddr_tipc *addr, void *usr_data,
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void *buf, size_t len)
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{
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struct tipc_subscriber *subscriber = usr_data;
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struct tipc_subscription *sub = NULL;
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struct tipc_net *tn = net_generic(net, tipc_net_id);
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spin_lock_bh(&subscriber->lock);
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tipc_subscrp_create(net, (struct tipc_subscr *)buf, subscriber, &sub);
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if (sub)
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tipc_nametbl_subscribe(sub);
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else
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tipc_conn_terminate(tn->topsrv, subscriber->conid);
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spin_unlock_bh(&subscriber->lock);
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}
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/* Handle one request to establish a new subscriber */
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static void *tipc_subscrb_connect_cb(int conid)
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{
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struct tipc_subscriber *subscriber;
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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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pr_warn("Subscriber rejected, no memory\n");
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return NULL;
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}
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INIT_LIST_HEAD(&subscriber->subscrp_list);
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subscriber->conid = conid;
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spin_lock_init(&subscriber->lock);
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return (void *)subscriber;
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}
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int tipc_topsrv_start(struct net *net)
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{
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struct tipc_net *tn = net_generic(net, tipc_net_id);
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const char name[] = "topology_server";
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struct tipc_server *topsrv;
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struct sockaddr_tipc *saddr;
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saddr = kzalloc(sizeof(*saddr), GFP_ATOMIC);
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if (!saddr)
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return -ENOMEM;
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saddr->family = AF_TIPC;
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saddr->addrtype = TIPC_ADDR_NAMESEQ;
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saddr->addr.nameseq.type = TIPC_TOP_SRV;
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saddr->addr.nameseq.lower = TIPC_TOP_SRV;
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saddr->addr.nameseq.upper = TIPC_TOP_SRV;
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saddr->scope = TIPC_NODE_SCOPE;
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topsrv = kzalloc(sizeof(*topsrv), GFP_ATOMIC);
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if (!topsrv) {
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kfree(saddr);
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return -ENOMEM;
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}
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topsrv->net = net;
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topsrv->saddr = saddr;
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topsrv->imp = TIPC_CRITICAL_IMPORTANCE;
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topsrv->type = SOCK_SEQPACKET;
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topsrv->max_rcvbuf_size = sizeof(struct tipc_subscr);
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topsrv->tipc_conn_recvmsg = tipc_subscrb_rcv_cb;
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topsrv->tipc_conn_new = tipc_subscrb_connect_cb;
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topsrv->tipc_conn_shutdown = tipc_subscrb_shutdown_cb;
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strncpy(topsrv->name, name, strlen(name) + 1);
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tn->topsrv = topsrv;
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atomic_set(&tn->subscription_count, 0);
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return tipc_server_start(topsrv);
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}
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void tipc_topsrv_stop(struct net *net)
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{
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struct tipc_net *tn = net_generic(net, tipc_net_id);
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struct tipc_server *topsrv = tn->topsrv;
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tipc_server_stop(topsrv);
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kfree(topsrv->saddr);
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kfree(topsrv);
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}
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