diff options
Diffstat (limited to 'net/tipc/subscr.c')
| -rw-r--r-- | net/tipc/subscr.c | 617 |
1 files changed, 617 insertions, 0 deletions
diff --git a/net/tipc/subscr.c b/net/tipc/subscr.c new file mode 100644 index 0000000..0747d8a --- /dev/null +++ b/net/tipc/subscr.c @@ -0,0 +1,617 @@ +/* + * net/tipc/subscr.c: TIPC network topology service + * + * Copyright (c) 2000-2006, Ericsson AB + * Copyright (c) 2005-2007, 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 "name_table.h" +#include "port.h" +#include "ref.h" +#include "subscr.h" + +/** + * struct subscriber - TIPC network topology subscriber + * @port_ref: object reference to server port connecting to subscriber + * @lock: pointer to spinlock controlling access to subscriber's server port + * @subscriber_list: adjacent subscribers in top. server's list of subscribers + * @subscription_list: list of subscription objects for this subscriber + */ + +struct subscriber { + u32 port_ref; + spinlock_t *lock; + struct list_head subscriber_list; + struct list_head subscription_list; +}; + +/** + * 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) +{ + return swap ? swab32(in) : in; +} + +/** + * subscr_send_event - send a message containing a tipc_event to the subscriber + * + * Note: Must not hold subscriber's server port lock, since tipc_send() will + * try to take the lock if the message is rejected and returned! + */ + +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->swap); + sub->evt.found_lower = htohl(found_lower, sub->swap); + sub->evt.found_upper = htohl(found_upper, sub->swap); + sub->evt.port.ref = htohl(port_ref, sub->swap); + sub->evt.port.node = htohl(node, sub->swap); + tipc_send(sub->server_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) +{ + if (!tipc_subscr_overlap(sub, found_lower, found_upper)) + return; + if (!must && !(sub->filter & TIPC_SUB_PORTS)) + return; + + sub->event_cb(sub, found_lower, found_upper, event, port_ref, node); +} + +/** + * subscr_timeout - subscription timeout has occurred + */ + +static void subscr_timeout(struct subscription *sub) +{ + struct port *server_port; + + /* Validate server port reference (in case subscriber is terminating) */ + + server_port = tipc_port_lock(sub->server_ref); + if (server_port == NULL) + return; + + /* Validate timeout (in case subscription is being cancelled) */ + + if (sub->timeout == TIPC_WAIT_FOREVER) { + tipc_port_unlock(server_port); + return; + } + + /* Unlink subscription from name table */ + + tipc_nametbl_unsubscribe(sub); + + /* Unlink subscription from subscriber */ + + list_del(&sub->subscription_list); + + /* Release subscriber's server port */ + + tipc_port_unlock(server_port); + + /* Notify subscriber of timeout */ + + subscr_send_event(sub, sub->evt.s.seq.lower, sub->evt.s.seq.upper, + TIPC_SUBSCR_TIMEOUT, 0, 0); + + /* Now destroy subscription */ + + k_term_timer(&sub->timer); + kfree(sub); + atomic_dec(&topsrv.subscription_count); +} + +/** + * subscr_del - delete a subscription within a subscription list + * + * Called with subscriber port 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 + * + * Called with subscriber port locked. Routine must temporarily release 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) +{ + u32 port_ref; + struct subscription *sub; + struct subscription *sub_temp; + + /* Invalidate subscriber reference */ + + port_ref = subscriber->port_ref; + subscriber->port_ref = 0; + spin_unlock_bh(subscriber->lock); + + /* Sever connection to subscriber */ + + tipc_shutdown(port_ref); + tipc_deleteport(port_ref); + + /* 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); + } + dbg("Term: Removing sub %u,%u,%u from subscriber %x list\n", + sub->seq.type, sub->seq.lower, sub->seq.upper, subscriber); + subscr_del(sub); + } + + /* Remove subscriber from topology server's subscriber list */ + + spin_lock_bh(&topsrv.lock); + list_del(&subscriber->subscriber_list); + spin_unlock_bh(&topsrv.lock); + + /* Reclaim subscriber lock */ + + spin_lock_bh(subscriber->lock); + + /* Now destroy subscriber */ + + kfree(subscriber); +} + +/** + * subscr_cancel - handle subscription cancellation request + * + * Called with subscriber port locked. Routine must temporarily release 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 + * + * Called with subscriber port locked. + */ + +static struct subscription *subscr_subscribe(struct tipc_subscr *s, + struct subscriber *subscriber) +{ + struct subscription *sub; + int swap; + + /* Determine subscriber's endianness */ + + swap = !(s->filter & (TIPC_SUB_PORTS | TIPC_SUB_SERVICE)); + + /* Detect & process a subscription cancellation request */ + + if (s->filter & htohl(TIPC_SUB_CANCEL, swap)) { + s->filter &= ~htohl(TIPC_SUB_CANCEL, swap); + subscr_cancel(s, subscriber); + return NULL; + } + + /* 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 NULL; + } + + /* Allocate subscription object */ + + sub = kmalloc(sizeof(*sub), GFP_ATOMIC); + if (!sub) { + warn("Subscription rejected, no memory\n"); + subscr_terminate(subscriber); + return NULL; + } + + /* Initialize subscription object */ + + sub->seq.type = htohl(s->seq.type, swap); + sub->seq.lower = htohl(s->seq.lower, swap); + sub->seq.upper = htohl(s->seq.upper, swap); + sub->timeout = htohl(s->timeout, swap); + sub->filter = htohl(s->filter, 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 NULL; + } + sub->event_cb = subscr_send_event; + INIT_LIST_HEAD(&sub->nameseq_list); + list_add(&sub->subscription_list, &subscriber->subscription_list); + sub->server_ref = subscriber->port_ref; + sub->swap = swap; + memcpy(&sub->evt.s, s, sizeof(struct tipc_subscr)); + 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); + } + + return sub; +} + +/** + * subscr_conn_shutdown_event - handle termination request from subscriber + * + * Called with subscriber's server port unlocked. + */ + +static void subscr_conn_shutdown_event(void *usr_handle, + u32 port_ref, + struct sk_buff **buf, + unsigned char const *data, + unsigned int size, + int reason) +{ + struct subscriber *subscriber = usr_handle; + spinlock_t *subscriber_lock; + + if (tipc_port_lock(port_ref) == NULL) + return; + + subscriber_lock = subscriber->lock; + subscr_terminate(subscriber); + spin_unlock_bh(subscriber_lock); +} + +/** + * subscr_conn_msg_event - handle new subscription request from subscriber + * + * Called with subscriber's server port unlocked. + */ + +static void subscr_conn_msg_event(void *usr_handle, + u32 port_ref, + struct sk_buff **buf, + const unchar *data, + u32 size) +{ + struct subscriber *subscriber = usr_handle; + spinlock_t *subscriber_lock; + struct subscription *sub; + + /* + * Lock subscriber's server port (& make a local copy of lock pointer, + * in case subscriber is deleted while processing subscription request) + */ + + if (tipc_port_lock(port_ref) == NULL) + return; + + subscriber_lock = subscriber->lock; + + if (size != sizeof(struct tipc_subscr)) { + subscr_terminate(subscriber); + spin_unlock_bh(subscriber_lock); + } else { + sub = subscr_subscribe((struct tipc_subscr *)data, subscriber); + spin_unlock_bh(subscriber_lock); + if (sub != NULL) { + + /* + * We must release the server port lock before adding a + * subscription to the name table since TIPC needs to be + * able to (re)acquire the port lock if an event message + * issued by the subscription process is rejected and + * returned. The subscription cannot be deleted while + * it is being added to the name table because: + * a) the single-threading of the native API port code + * ensures the subscription cannot be cancelled and + * the subscriber connection cannot be broken, and + * b) the name table lock ensures the subscription + * timeout code cannot delete the subscription, + * so the subscription object is still protected. + */ + + tipc_nametbl_subscribe(sub); + } + } +} + +/** + * 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) +{ + static struct iovec msg_sect = {NULL, 0}; + + struct subscriber *subscriber; + u32 server_port_ref; + + /* 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); + + /* Create server port & establish connection to subscriber */ + + tipc_createport(topsrv.user_ref, + subscriber, + 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"); + kfree(subscriber); + return; + } + tipc_connect2port(subscriber->port_ref, orig); + + /* Lock server port (& save lock address for future use) */ + + subscriber->lock = tipc_port_lock(subscriber->port_ref)->publ.lock; + + /* Add subscriber to topology server's subscriber list */ + + spin_lock_bh(&topsrv.lock); + list_add(&subscriber->subscriber_list, &topsrv.subscriber_list); + spin_unlock_bh(&topsrv.lock); + + /* Unlock server port */ + + server_port_ref = subscriber->port_ref; + spin_unlock_bh(subscriber->lock); + + /* Send an ACK- to complete connection handshaking */ + + tipc_send(server_port_ref, 1, &msg_sect); + + /* Handle optional subscription request */ + + if (size != 0) { + subscr_conn_msg_event(subscriber, server_port_ref, + buf, data, size); + } +} + +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) { + subscriber_lock = subscriber->lock; + spin_lock_bh(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); +} + |
