tipc: rename tipc_server to tipc_topsrv

We rename struct tipc_server to struct tipc_topsrv. This reflect its now
specialized role as topology server. Accoringly, we change or add function
prefixes to make it clearer which functionality those belong to.

There are no functional changes in this commit.

Acked-by: Ying.Xue <ying.xue@windriver.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 702 insertions, 0 deletions

diff --git a/net/tipc/topsrv.c b/net/tipc/topsrv.c
new file mode 100644
index 000000000000..02013e00f287
--- /dev/null
+++ b/net/tipc/topsrv.c
@@ -0,0 +1,702 @@
+/*
+ * net/tipc/server.c: TIPC server infrastructure
+ *
+ * Copyright (c) 2012-2013, Wind River Systems
+ * Copyright (c) 2017-2018, Ericsson AB
+ * 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 "subscr.h"
+#include "topsrv.h"
+#include "core.h"
+#include "socket.h"
+#include "addr.h"
+#include "msg.h"
+#include <net/sock.h>
+#include <linux/module.h>
+
+/* Number of messages to send before rescheduling */
+#define MAX_SEND_MSG_COUNT	25
+#define MAX_RECV_MSG_COUNT	25
+#define CF_CONNECTED		1
+#define CF_SERVER		2
+
+#define TIPC_SERVER_NAME_LEN	32
+
+/**
+ * struct tipc_topsrv - TIPC server structure
+ * @conn_idr: identifier set of connection
+ * @idr_lock: protect the connection identifier set
+ * @idr_in_use: amount of allocated identifier entry
+ * @net: network namspace instance
+ * @rcvbuf_cache: memory cache of server receive buffer
+ * @rcv_wq: receive workqueue
+ * @send_wq: send workqueue
+ * @max_rcvbuf_size: maximum permitted receive message length
+ * @tipc_conn_new: callback will be called when new connection is incoming
+ * @tipc_conn_release: callback will be called before releasing the connection
+ * @tipc_conn_recvmsg: callback will be called when message arrives
+ * @name: server name
+ * @imp: message importance
+ * @type: socket type
+ */
+struct tipc_topsrv {
+	struct idr conn_idr;
+	spinlock_t idr_lock; /* for idr list */
+	int idr_in_use;
+	struct net *net;
+	struct work_struct awork;
+	struct workqueue_struct *rcv_wq;
+	struct workqueue_struct *send_wq;
+	int max_rcvbuf_size;
+	struct socket *listener;
+	char name[TIPC_SERVER_NAME_LEN];
+};
+
+/**
+ * struct tipc_conn - TIPC connection structure
+ * @kref: reference counter to connection object
+ * @conid: connection identifier
+ * @sock: socket handler associated with connection
+ * @flags: indicates connection state
+ * @server: pointer to connected server
+ * @sub_list: lsit to all pertaing subscriptions
+ * @sub_lock: lock protecting the subscription list
+ * @outqueue_lock: control access to the outqueue
+ * @rwork: receive work item
+ * @rx_action: what to do when connection socket is active
+ * @outqueue: pointer to first outbound message in queue
+ * @outqueue_lock: control access to the outqueue
+ * @swork: send work item
+ */
+struct tipc_conn {
+	struct kref kref;
+	int conid;
+	struct socket *sock;
+	unsigned long flags;
+	struct tipc_topsrv *server;
+	struct list_head sub_list;
+	spinlock_t sub_lock; /* for subscription list */
+	struct work_struct rwork;
+	struct list_head outqueue;
+	spinlock_t outqueue_lock; /* for outqueue */
+	struct work_struct swork;
+};
+
+/* An entry waiting to be sent */
+struct outqueue_entry {
+	bool inactive;
+	struct tipc_event evt;
+	struct list_head list;
+};
+
+static void tipc_conn_recv_work(struct work_struct *work);
+static void tipc_conn_send_work(struct work_struct *work);
+static void tipc_topsrv_kern_evt(struct net *net, struct tipc_event *evt);
+static void tipc_conn_delete_sub(struct tipc_conn *con, struct tipc_subscr *s);
+
+static bool connected(struct tipc_conn *con)
+{
+	return con && test_bit(CF_CONNECTED, &con->flags);
+}
+
+static void tipc_conn_kref_release(struct kref *kref)
+{
+	struct tipc_conn *con = container_of(kref, struct tipc_conn, kref);
+	struct tipc_topsrv *s = con->server;
+	struct outqueue_entry *e, *safe;
+
+	spin_lock_bh(&s->idr_lock);
+	idr_remove(&s->conn_idr, con->conid);
+	s->idr_in_use--;
+	spin_unlock_bh(&s->idr_lock);
+	if (con->sock)
+		sock_release(con->sock);
+
+	spin_lock_bh(&con->outqueue_lock);
+	list_for_each_entry_safe(e, safe, &con->outqueue, list) {
+		list_del(&e->list);
+		kfree(e);
+	}
+	spin_unlock_bh(&con->outqueue_lock);
+	kfree(con);
+}
+
+static void conn_put(struct tipc_conn *con)
+{
+	kref_put(&con->kref, tipc_conn_kref_release);
+}
+
+static void conn_get(struct tipc_conn *con)
+{
+	kref_get(&con->kref);
+}
+
+static void tipc_conn_close(struct tipc_conn *con)
+{
+	struct sock *sk = con->sock->sk;
+	bool disconnect = false;
+
+	write_lock_bh(&sk->sk_callback_lock);
+	disconnect = test_and_clear_bit(CF_CONNECTED, &con->flags);
+
+	if (disconnect) {
+		sk->sk_user_data = NULL;
+		tipc_conn_delete_sub(con, NULL);
+	}
+	write_unlock_bh(&sk->sk_callback_lock);
+
+	/* Handle concurrent calls from sending and receiving threads */
+	if (!disconnect)
+		return;
+
+	/* Don't flush pending works, -just let them expire */
+	kernel_sock_shutdown(con->sock, SHUT_RDWR);
+
+	conn_put(con);
+}
+
+static struct tipc_conn *tipc_conn_alloc(struct tipc_topsrv *s)
+{
+	struct tipc_conn *con;
+	int ret;
+
+	con = kzalloc(sizeof(*con), GFP_ATOMIC);
+	if (!con)
+		return ERR_PTR(-ENOMEM);
+
+	kref_init(&con->kref);
+	INIT_LIST_HEAD(&con->outqueue);
+	INIT_LIST_HEAD(&con->sub_list);
+	spin_lock_init(&con->outqueue_lock);
+	spin_lock_init(&con->sub_lock);
+	INIT_WORK(&con->swork, tipc_conn_send_work);
+	INIT_WORK(&con->rwork, tipc_conn_recv_work);
+
+	spin_lock_bh(&s->idr_lock);
+	ret = idr_alloc(&s->conn_idr, con, 0, 0, GFP_ATOMIC);
+	if (ret < 0) {
+		kfree(con);
+		spin_unlock_bh(&s->idr_lock);
+		return ERR_PTR(-ENOMEM);
+	}
+	con->conid = ret;
+	s->idr_in_use++;
+	spin_unlock_bh(&s->idr_lock);
+
+	set_bit(CF_CONNECTED, &con->flags);
+	con->server = s;
+
+	return con;
+}
+
+static struct tipc_conn *tipc_conn_lookup(struct tipc_topsrv *s, int conid)
+{
+	struct tipc_conn *con;
+
+	spin_lock_bh(&s->idr_lock);
+	con = idr_find(&s->conn_idr, conid);
+	if (!connected(con) || !kref_get_unless_zero(&con->kref))
+		con = NULL;
+	spin_unlock_bh(&s->idr_lock);
+	return con;
+}
+
+/* tipc_conn_delete_sub - delete a specific or all subscriptions
+ * for a given subscriber
+ */
+static void tipc_conn_delete_sub(struct tipc_conn *con, struct tipc_subscr *s)
+{
+	struct tipc_net *tn = tipc_net(con->server->net);
+	struct list_head *sub_list = &con->sub_list;
+	struct tipc_subscription *sub, *tmp;
+
+	spin_lock_bh(&con->sub_lock);
+	list_for_each_entry_safe(sub, tmp, sub_list, sub_list) {
+		if (!s || !memcmp(s, &sub->evt.s, sizeof(*s))) {
+			tipc_sub_unsubscribe(sub);
+			atomic_dec(&tn->subscription_count);
+		} else if (s) {
+			break;
+		}
+	}
+	spin_unlock_bh(&con->sub_lock);
+}
+
+static void tipc_conn_send_to_sock(struct tipc_conn *con)
+{
+	struct list_head *queue = &con->outqueue;
+	struct tipc_topsrv *srv = con->server;
+	struct outqueue_entry *e;
+	struct tipc_event *evt;
+	struct msghdr msg;
+	struct kvec iov;
+	int count = 0;
+	int ret;
+
+	spin_lock_bh(&con->outqueue_lock);
+
+	while (!list_empty(queue)) {
+		e = list_first_entry(queue, struct outqueue_entry, list);
+		evt = &e->evt;
+		spin_unlock_bh(&con->outqueue_lock);
+
+		if (e->inactive)
+			tipc_conn_delete_sub(con, &evt->s);
+
+		memset(&msg, 0, sizeof(msg));
+		msg.msg_flags = MSG_DONTWAIT;
+		iov.iov_base = evt;
+		iov.iov_len = sizeof(*evt);
+		msg.msg_name = NULL;
+
+		if (con->sock) {
+			ret = kernel_sendmsg(con->sock, &msg, &iov,
+					     1, sizeof(*evt));
+			if (ret == -EWOULDBLOCK || ret == 0) {
+				cond_resched();
+				return;
+			} else if (ret < 0) {
+				return tipc_conn_close(con);
+			}
+		} else {
+			tipc_topsrv_kern_evt(srv->net, evt);
+		}
+
+		/* Don't starve users filling buffers */
+		if (++count >= MAX_SEND_MSG_COUNT) {
+			cond_resched();
+			count = 0;
+		}
+		spin_lock_bh(&con->outqueue_lock);
+		list_del(&e->list);
+		kfree(e);
+	}
+	spin_unlock_bh(&con->outqueue_lock);
+}
+
+static void tipc_conn_send_work(struct work_struct *work)
+{
+	struct tipc_conn *con = container_of(work, struct tipc_conn, swork);
+
+	if (connected(con))
+		tipc_conn_send_to_sock(con);
+
+	conn_put(con);
+}
+
+/* tipc_conn_queue_evt() - interrupt level call from a subscription instance
+ * The queued work is launched into tipc_send_work()->tipc_send_to_sock()
+ */
+void tipc_topsrv_queue_evt(struct net *net, int conid,
+			   u32 event, struct tipc_event *evt)
+{
+	struct tipc_topsrv *srv = tipc_topsrv(net);
+	struct outqueue_entry *e;
+	struct tipc_conn *con;
+
+	con = tipc_conn_lookup(srv, conid);
+	if (!con)
+		return;
+
+	if (!connected(con))
+		goto err;
+
+	e = kmalloc(sizeof(*e), GFP_ATOMIC);
+	if (!e)
+		goto err;
+	e->inactive = (event == TIPC_SUBSCR_TIMEOUT);
+	memcpy(&e->evt, evt, sizeof(*evt));
+	spin_lock_bh(&con->outqueue_lock);
+	list_add_tail(&e->list, &con->outqueue);
+	spin_unlock_bh(&con->outqueue_lock);
+
+	if (queue_work(srv->send_wq, &con->swork))
+		return;
+err:
+	conn_put(con);
+}
+
+/* tipc_conn_write_space - interrupt callback after a sendmsg EAGAIN
+ * Indicates that there now is more space in the send buffer
+ * The queued work is launched into tipc_send_work()->tipc_conn_send_to_sock()
+ */
+static void tipc_conn_write_space(struct sock *sk)
+{
+	struct tipc_conn *con;
+
+	read_lock_bh(&sk->sk_callback_lock);
+	con = sk->sk_user_data;
+	if (connected(con)) {
+		conn_get(con);
+		if (!queue_work(con->server->send_wq, &con->swork))
+			conn_put(con);
+	}
+	read_unlock_bh(&sk->sk_callback_lock);
+}
+
+static int tipc_conn_rcv_sub(struct tipc_topsrv *srv,
+			     struct tipc_conn *con,
+			     struct tipc_subscr *s)
+{
+	struct tipc_net *tn = tipc_net(srv->net);
+	struct tipc_subscription *sub;
+
+	if (tipc_sub_read(s, filter) & TIPC_SUB_CANCEL) {
+		tipc_conn_delete_sub(con, s);
+		return 0;
+	}
+	if (atomic_read(&tn->subscription_count) >= TIPC_MAX_SUBSCR) {
+		pr_warn("Subscription rejected, max (%u)\n", TIPC_MAX_SUBSCR);
+		return -1;
+	}
+	sub = tipc_sub_subscribe(srv->net, s, con->conid);
+	if (!sub)
+		return -1;
+	atomic_inc(&tn->subscription_count);
+	spin_lock_bh(&con->sub_lock);
+	list_add(&sub->sub_list, &con->sub_list);
+	spin_unlock_bh(&con->sub_lock);
+	return 0;
+}
+
+static int tipc_conn_rcv_from_sock(struct tipc_conn *con)
+{
+	struct tipc_topsrv *srv = con->server;
+	struct sock *sk = con->sock->sk;
+	struct msghdr msg = {};
+	struct tipc_subscr s;
+	struct kvec iov;
+	int ret;
+
+	iov.iov_base = &s;
+	iov.iov_len = sizeof(s);
+	msg.msg_name = NULL;
+	iov_iter_kvec(&msg.msg_iter, READ | ITER_KVEC, &iov, 1, iov.iov_len);
+	ret = sock_recvmsg(con->sock, &msg, MSG_DONTWAIT);
+	if (ret == -EWOULDBLOCK)
+		return -EWOULDBLOCK;
+	if (ret > 0) {
+		read_lock_bh(&sk->sk_callback_lock);
+		ret = tipc_conn_rcv_sub(srv, con, &s);
+		read_unlock_bh(&sk->sk_callback_lock);
+	}
+	if (ret < 0)
+		tipc_conn_close(con);
+
+	return ret;
+}
+
+static void tipc_conn_recv_work(struct work_struct *work)
+{
+	struct tipc_conn *con = container_of(work, struct tipc_conn, rwork);
+	int count = 0;
+
+	while (connected(con)) {
+		if (tipc_conn_rcv_from_sock(con))
+			break;
+
+		/* Don't flood Rx machine */
+		if (++count >= MAX_RECV_MSG_COUNT) {
+			cond_resched();
+			count = 0;
+		}
+	}
+	conn_put(con);
+}
+
+/* tipc_conn_data_ready - interrupt callback indicating the socket has data
+ * The queued work is launched into tipc_recv_work()->tipc_conn_rcv_from_sock()
+ */
+static void tipc_conn_data_ready(struct sock *sk)
+{
+	struct tipc_conn *con;
+
+	read_lock_bh(&sk->sk_callback_lock);
+	con = sk->sk_user_data;
+	if (connected(con)) {
+		conn_get(con);
+		if (!queue_work(con->server->rcv_wq, &con->rwork))
+			conn_put(con);
+	}
+	read_unlock_bh(&sk->sk_callback_lock);
+}
+
+static void tipc_topsrv_accept(struct work_struct *work)
+{
+	struct tipc_topsrv *srv = container_of(work, struct tipc_topsrv, awork);
+	struct socket *lsock = srv->listener;
+	struct socket *newsock;
+	struct tipc_conn *con;
+	struct sock *newsk;
+	int ret;
+
+	while (1) {
+		ret = kernel_accept(lsock, &newsock, O_NONBLOCK);
+		if (ret < 0)
+			return;
+		con = tipc_conn_alloc(srv);
+		if (IS_ERR(con)) {
+			ret = PTR_ERR(con);
+			sock_release(newsock);
+			return;
+		}
+		/* Register callbacks */
+		newsk = newsock->sk;
+		write_lock_bh(&newsk->sk_callback_lock);
+		newsk->sk_data_ready = tipc_conn_data_ready;
+		newsk->sk_write_space = tipc_conn_write_space;
+		newsk->sk_user_data = con;
+		con->sock = newsock;
+		write_unlock_bh(&newsk->sk_callback_lock);
+
+		/* Wake up receive process in case of 'SYN+' message */
+		newsk->sk_data_ready(newsk);
+	}
+}
+
+/* tipc_toprsv_listener_data_ready - interrupt callback with connection request
+ * The queued job is launched into tipc_topsrv_accept()
+ */
+static void tipc_topsrv_listener_data_ready(struct sock *sk)
+{
+	struct tipc_topsrv *srv;
+
+	read_lock_bh(&sk->sk_callback_lock);
+	srv = sk->sk_user_data;
+	if (srv->listener)
+		queue_work(srv->rcv_wq, &srv->awork);
+	read_unlock_bh(&sk->sk_callback_lock);
+}
+
+static int tipc_topsrv_create_listener(struct tipc_topsrv *srv)
+{
+	int imp = TIPC_CRITICAL_IMPORTANCE;
+	struct socket *lsock = NULL;
+	struct sockaddr_tipc saddr;
+	struct sock *sk;
+	int rc;
+
+	rc = sock_create_kern(srv->net, AF_TIPC, SOCK_SEQPACKET, 0, &lsock);
+	if (rc < 0)
+		return rc;
+
+	srv->listener = lsock;
+	sk = lsock->sk;
+	write_lock_bh(&sk->sk_callback_lock);
+	sk->sk_data_ready = tipc_topsrv_listener_data_ready;
+	sk->sk_user_data = srv;
+	write_unlock_bh(&sk->sk_callback_lock);
+
+	rc = kernel_setsockopt(lsock, SOL_TIPC, TIPC_IMPORTANCE,
+			       (char *)&imp, sizeof(imp));
+	if (rc < 0)
+		goto err;
+
+	saddr.family	                = AF_TIPC;
+	saddr.addrtype		        = TIPC_ADDR_NAMESEQ;
+	saddr.addr.nameseq.type	        = TIPC_TOP_SRV;
+	saddr.addr.nameseq.lower	= TIPC_TOP_SRV;
+	saddr.addr.nameseq.upper	= TIPC_TOP_SRV;
+	saddr.scope			= TIPC_NODE_SCOPE;
+
+	rc = kernel_bind(lsock, (struct sockaddr *)&saddr, sizeof(saddr));
+	if (rc < 0)
+		goto err;
+	rc = kernel_listen(lsock, 0);
+	if (rc < 0)
+		goto err;
+
+	/* As server's listening socket owner and creator is the same module,
+	 * we have to decrease TIPC module reference count to guarantee that
+	 * it remains zero after the server socket is created, otherwise,
+	 * executing "rmmod" command is unable to make TIPC module deleted
+	 * after TIPC module is inserted successfully.
+	 *
+	 * However, the reference count is ever increased twice in
+	 * sock_create_kern(): one is to increase the reference count of owner
+	 * of TIPC socket's proto_ops struct; another is to increment the
+	 * reference count of owner of TIPC proto struct. Therefore, we must
+	 * decrement the module reference count twice to ensure that it keeps
+	 * zero after server's listening socket is created. Of course, we
+	 * must bump the module reference count twice as well before the socket
+	 * is closed.
+	 */
+	module_put(lsock->ops->owner);
+	module_put(sk->sk_prot_creator->owner);
+
+	return 0;
+err:
+	sock_release(lsock);
+	return -EINVAL;
+}
+
+bool tipc_topsrv_kern_subscr(struct net *net, u32 port, u32 type, u32 lower,
+			     u32 upper, u32 filter, int *conid)
+{
+	struct tipc_subscr sub;
+	struct tipc_conn *con;
+	int rc;
+
+	sub.seq.type = type;
+	sub.seq.lower = lower;
+	sub.seq.upper = upper;
+	sub.timeout = TIPC_WAIT_FOREVER;
+	sub.filter = filter;
+	*(u32 *)&sub.usr_handle = port;
+
+	con = tipc_conn_alloc(tipc_topsrv(net));
+	if (IS_ERR(con))
+		return false;
+
+	*conid = con->conid;
+	con->sock = NULL;
+	rc = tipc_conn_rcv_sub(tipc_topsrv(net), con, &sub);
+	if (rc < 0)
+		tipc_conn_close(con);
+	return !rc;
+}
+
+void tipc_topsrv_kern_unsubscr(struct net *net, int conid)
+{
+	struct tipc_conn *con;
+
+	con = tipc_conn_lookup(tipc_topsrv(net), conid);
+	if (!con)
+		return;
+
+	test_and_clear_bit(CF_CONNECTED, &con->flags);
+	tipc_conn_delete_sub(con, NULL);
+	conn_put(con);
+	conn_put(con);
+}
+
+static void tipc_topsrv_kern_evt(struct net *net, struct tipc_event *evt)
+{
+	u32 port = *(u32 *)&evt->s.usr_handle;
+	u32 self = tipc_own_addr(net);
+	struct sk_buff_head evtq;
+	struct sk_buff *skb;
+
+	skb = tipc_msg_create(TOP_SRV, 0, INT_H_SIZE, sizeof(*evt),
+			      self, self, port, port, 0);
+	if (!skb)
+		return;
+	msg_set_dest_droppable(buf_msg(skb), true);
+	memcpy(msg_data(buf_msg(skb)), evt, sizeof(*evt));
+	skb_queue_head_init(&evtq);
+	__skb_queue_tail(&evtq, skb);
+	tipc_sk_rcv(net, &evtq);
+}
+
+static int tipc_topsrv_work_start(struct tipc_topsrv *s)
+{
+	s->rcv_wq = alloc_ordered_workqueue("tipc_rcv", 0);
+	if (!s->rcv_wq) {
+		pr_err("can't start tipc receive workqueue\n");
+		return -ENOMEM;
+	}
+
+	s->send_wq = alloc_ordered_workqueue("tipc_send", 0);
+	if (!s->send_wq) {
+		pr_err("can't start tipc send workqueue\n");
+		destroy_workqueue(s->rcv_wq);
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static void tipc_topsrv_work_stop(struct tipc_topsrv *s)
+{
+	destroy_workqueue(s->rcv_wq);
+	destroy_workqueue(s->send_wq);
+}
+
+int tipc_topsrv_start(struct net *net)
+{
+	struct tipc_net *tn = tipc_net(net);
+	const char name[] = "topology_server";
+	struct tipc_topsrv *srv;
+	int ret;
+
+	srv = kzalloc(sizeof(*srv), GFP_ATOMIC);
+	if (!srv)
+		return -ENOMEM;
+
+	srv->net = net;
+	srv->max_rcvbuf_size = sizeof(struct tipc_subscr);
+	INIT_WORK(&srv->awork, tipc_topsrv_accept);
+
+	strncpy(srv->name, name, strlen(name) + 1);
+	tn->topsrv = srv;
+	atomic_set(&tn->subscription_count, 0);
+
+	spin_lock_init(&srv->idr_lock);
+	idr_init(&srv->conn_idr);
+	srv->idr_in_use = 0;
+
+	ret = tipc_topsrv_work_start(srv);
+	if (ret < 0)
+		return ret;
+
+	ret = tipc_topsrv_create_listener(srv);
+	if (ret < 0)
+		tipc_topsrv_work_stop(srv);
+
+	return ret;
+}
+
+void tipc_topsrv_stop(struct net *net)
+{
+	struct tipc_topsrv *srv = tipc_topsrv(net);
+	struct socket *lsock = srv->listener;
+	struct tipc_conn *con;
+	int id;
+
+	spin_lock_bh(&srv->idr_lock);
+	for (id = 0; srv->idr_in_use; id++) {
+		con = idr_find(&srv->conn_idr, id);
+		if (con) {
+			spin_unlock_bh(&srv->idr_lock);
+			tipc_conn_close(con);
+			spin_lock_bh(&srv->idr_lock);
+		}
+	}
+	__module_get(lsock->ops->owner);
+	__module_get(lsock->sk->sk_prot_creator->owner);
+	sock_release(lsock);
+	srv->listener = NULL;
+	spin_unlock_bh(&srv->idr_lock);
+	tipc_topsrv_work_stop(srv);
+	idr_destroy(&srv->conn_idr);
+	kfree(srv);
+}