/*
* 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 *)∈
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;
/* 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_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);
}
tipc_nametbl_unsubscribe(sub);
list_del(&sub->subscription_list);
dbg("Term: Removed sub %u,%u,%u from subscriber %x list\n",
sub->seq.type, sub->seq.lower, sub->seq.upper, subscriber);
kfree(sub);
atomic_dec(&topsrv.subscription_count);
}
/* 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_subscribe - create subscription for subscriber
*
* Called with subscriber locked
*/
static void subscr_subscribe(struct tipc_subscr *s,
struct subscriber *subscriber)
{
struct subscription *sub;
/* 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;
}
/* Determine/update subscriber's endianness */
if ((s->filter == TIPC_SUB_PORTS) || (s->filter == TIPC_SUB_SERVICE))
subscriber->swap = 0;
else
subscriber->swap = 1;
/* 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);
}
