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[TIPC]: Added subscription cancellation capability

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This patch allows a TIPC application to cancel an existing
topology service subscription by re-requesting the subscription
with the TIPC_SUB_CANCEL filter bit set.  (All other bits of
the cancel request must match the original subscription request.)

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Per Liden <per.liden@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Lijun Chen 2006-10-16 21:59:42 -07:00 committed by David S. Miller
parent fc144deec6
commit eb409460b1
2 changed files with 85 additions and 15 deletions
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1
include/linux/tipc.h
View File

@ -129,6 +129,7 @@ static inline unsigned int tipc_node(__u32 addr)
#define TIPC_SUB_PORTS 0x01 /* filter for port availability */
#define TIPC_SUB_SERVICE 0x02 /* filter for service availability */
#define TIPC_SUB_CANCEL 0x04 /* cancel a subscription */
#if 0
/* The following filter options are not currently implemented */
#define TIPC_SUB_NO_BIND_EVTS 0x04 /* filter out "publish" events */

99
net/tipc/subscr.c
View File

@ -155,7 +155,7 @@ void tipc_subscr_report_overlap(struct subscription *sub,
sub->seq.upper, found_lower, found_upper);
if (!tipc_subscr_overlap(sub, found_lower, found_upper))
return;
if (!must && (sub->filter != TIPC_SUB_PORTS))
if (!must && !(sub->filter & TIPC_SUB_PORTS))
return;
subscr_send_event(sub, found_lower, found_upper, event, port_ref, node);
}
@ -176,6 +176,13 @@ static void subscr_timeout(struct subscription *sub)
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);
@ -198,6 +205,20 @@ static void subscr_timeout(struct subscription *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
*
@ -227,12 +248,9 @@ static void subscr_terminate(struct subscriber *subscriber)
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",
dbg("Term: Removing 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);
subscr_del(sub);
}
/* Sever connection to subscriber */
@ -252,6 +270,49 @@ static void subscr_terminate(struct subscriber *subscriber)
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
*
@ -263,6 +324,21 @@ static void subscr_subscribe(struct tipc_subscr *s,
{
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) {
@ -281,13 +357,6 @@ static void subscr_subscribe(struct tipc_subscr *s,
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));
@ -296,8 +365,8 @@ static void subscr_subscribe(struct tipc_subscr *s,
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)))
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);