1 files changed, 375 insertions, 0 deletions
diff --git a/net/tipc/subscr.c b/net/tipc/subscr.c
new file mode 100644
index 00000000000..642437231ad
--- /dev/null
+++ b/net/tipc/subscr.c
@@ -0,0 +1,375 @@
+/*
+ * net/tipc/subscr.c: TIPC network topology service
+ *
+ * Copyright (c) 2000-2006, Ericsson AB
+ * Copyright (c) 2005-2007, 2010-2013, 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 "name_table.h"
+#include "port.h"
+#include "subscr.h"
+
+/**
+ * struct tipc_subscriber - TIPC network topology subscriber
+ * @conid: connection identifier to server connecting to subscriber
+ * @lock: control access to subscriber
+ * @subscription_list: list of subscription objects for this subscriber
+ */
+struct tipc_subscriber {
+	int conid;
+	spinlock_t lock;
+	struct list_head subscription_list;
+};
+
+static void subscr_conn_msg_event(int conid, struct sockaddr_tipc *addr,
+				  void *usr_data, void *buf, size_t len);
+static void *subscr_named_msg_event(int conid);
+static void subscr_conn_shutdown_event(int conid, void *usr_data);
+
+static atomic_t subscription_count = ATOMIC_INIT(0);
+
+static struct sockaddr_tipc topsrv_addr __read_mostly = {
+	.family			= AF_TIPC,
+	.addrtype		= TIPC_ADDR_NAMESEQ,
+	.addr.nameseq.type	= TIPC_TOP_SRV,
+	.addr.nameseq.lower	= TIPC_TOP_SRV,
+	.addr.nameseq.upper	= TIPC_TOP_SRV,
+	.scope			= TIPC_NODE_SCOPE
+};
+
+static struct tipc_server topsrv __read_mostly = {
+	.saddr			= &topsrv_addr,
+	.imp			= TIPC_CRITICAL_IMPORTANCE,
+	.type			= SOCK_SEQPACKET,
+	.max_rcvbuf_size	= sizeof(struct tipc_subscr),
+	.name			= "topology_server",
+	.tipc_conn_recvmsg	= subscr_conn_msg_event,
+	.tipc_conn_new		= subscr_named_msg_event,
+	.tipc_conn_shutdown	= subscr_conn_shutdown_event,
+};
+
+/**
+ * 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;
+}
+
+static void subscr_send_event(struct tipc_subscription *sub, u32 found_lower,
+			      u32 found_upper, u32 event, u32 port_ref,
+			      u32 node)
+{
+	struct tipc_subscriber *subscriber = sub->subscriber;
+	struct kvec 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_conn_sendmsg(&topsrv, subscriber->conid, NULL, msg_sect.iov_base,
+			  msg_sect.iov_len);
+}
+
+/**
+ * tipc_subscr_overlap - test for subscription overlap with the given values
+ *
+ * Returns 1 if there is overlap, otherwise 0.
+ */
+int tipc_subscr_overlap(struct tipc_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 tipc_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;
+
+	subscr_send_event(sub, found_lower, found_upper, event, port_ref, node);
+}
+
+static void subscr_timeout(struct tipc_subscription *sub)
+{
+	struct tipc_subscriber *subscriber = sub->subscriber;
+
+	/* The spin lock per subscriber is used to protect its members */
+	spin_lock_bh(&subscriber->lock);
+
+	/* Validate timeout (in case subscription is being cancelled) */
+	if (sub->timeout == TIPC_WAIT_FOREVER) {
+		spin_unlock_bh(&subscriber->lock);
+		return;
+	}
+
+	/* Unlink subscription from name table */
+	tipc_nametbl_unsubscribe(sub);
+
+	/* Unlink subscription from subscriber */
+	list_del(&sub->subscription_list);
+
+	spin_unlock_bh(&subscriber->lock);
+
+	/* 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(&subscription_count);
+}
+
+/**
+ * subscr_del - delete a subscription within a subscription list
+ *
+ * Called with subscriber lock held.
+ */
+static void subscr_del(struct tipc_subscription *sub)
+{
+	tipc_nametbl_unsubscribe(sub);
+	list_del(&sub->subscription_list);
+	kfree(sub);
+	atomic_dec(&subscription_count);
+}
+
+/**
+ * subscr_terminate - terminate communication with a subscriber
+ *
+ * Note: Must call it in process context since it might sleep.
+ */
+static void subscr_terminate(struct tipc_subscriber *subscriber)
+{
+	tipc_conn_terminate(&topsrv, subscriber->conid);
+}
+
+static void subscr_release(struct tipc_subscriber *subscriber)
+{
+	struct tipc_subscription *sub;
+	struct tipc_subscription *sub_temp;
+
+	spin_lock_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) {
+			spin_unlock_bh(&subscriber->lock);
+			k_cancel_timer(&sub->timer);
+			k_term_timer(&sub->timer);
+			spin_lock_bh(&subscriber->lock);
+		}
+		subscr_del(sub);
+	}
+	spin_unlock_bh(&subscriber->lock);
+
+	/* Now destroy subscriber */
+	kfree(subscriber);
+}
+
+/**
+ * subscr_cancel - handle subscription cancellation request
+ *
+ * Called with subscriber lock held. 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 tipc_subscriber *subscriber)
+{
+	struct tipc_subscription *sub;
+	struct tipc_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);
+	}
+	subscr_del(sub);
+}
+
+/**
+ * subscr_subscribe - create subscription for subscriber
+ *
+ * Called with subscriber lock held.
+ */
+static int subscr_subscribe(struct tipc_subscr *s,
+			    struct tipc_subscriber *subscriber,
+			    struct tipc_subscription **sub_p) {
+	struct tipc_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 0;
+	}
+
+	/* Refuse subscription if global limit exceeded */
+	if (atomic_read(&subscription_count) >= TIPC_MAX_SUBSCRIPTIONS) {
+		pr_warn("Subscription rejected, limit reached (%u)\n",
+			TIPC_MAX_SUBSCRIPTIONS);
+		return -EINVAL;
+	}
+
+	/* Allocate subscription object */
+	sub = kmalloc(sizeof(*sub), GFP_ATOMIC);
+	if (!sub) {
+		pr_warn("Subscription rejected, no memory\n");
+		return -ENOMEM;
+	}
+
+	/* 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)) {
+		pr_warn("Subscription rejected, illegal request\n");
+		kfree(sub);
+		return -EINVAL;
+	}
+	INIT_LIST_HEAD(&sub->nameseq_list);
+	list_add(&sub->subscription_list, &subscriber->subscription_list);
+	sub->subscriber = subscriber;
+	sub->swap = swap;
+	memcpy(&sub->evt.s, s, sizeof(struct tipc_subscr));
+	atomic_inc(&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_p = sub;
+	return 0;
+}
+
+/* Handle one termination request for the subscriber */
+static void subscr_conn_shutdown_event(int conid, void *usr_data)
+{
+	subscr_release((struct tipc_subscriber *)usr_data);
+}
+
+/* Handle one request to create a new subscription for the subscriber */
+static void subscr_conn_msg_event(int conid, struct sockaddr_tipc *addr,
+				  void *usr_data, void *buf, size_t len)
+{
+	struct tipc_subscriber *subscriber = usr_data;
+	struct tipc_subscription *sub = NULL;
+
+	spin_lock_bh(&subscriber->lock);
+	if (subscr_subscribe((struct tipc_subscr *)buf, subscriber, &sub) < 0) {
+		spin_unlock_bh(&subscriber->lock);
+		subscr_terminate(subscriber);
+		return;
+	}
+	if (sub)
+		tipc_nametbl_subscribe(sub);
+	spin_unlock_bh(&subscriber->lock);
+}
+
+
+/* Handle one request to establish a new subscriber */
+static void *subscr_named_msg_event(int conid)
+{
+	struct tipc_subscriber *subscriber;
+
+	/* Create subscriber object */
+	subscriber = kzalloc(sizeof(struct tipc_subscriber), GFP_ATOMIC);
+	if (subscriber == NULL) {
+		pr_warn("Subscriber rejected, no memory\n");
+		return NULL;
+	}
+	INIT_LIST_HEAD(&subscriber->subscription_list);
+	subscriber->conid = conid;
+	spin_lock_init(&subscriber->lock);
+
+	return (void *)subscriber;
+}
+
+int tipc_subscr_start(void)
+{
+	return tipc_server_start(&topsrv);
+}
+
+void tipc_subscr_stop(void)
+{
+	tipc_server_stop(&topsrv);
+}