2 * net/tipc/server.c: TIPC server infrastructure
4 * Copyright (c) 2012-2013, Wind River Systems
5 * Copyright (c) 2017-2018, Ericsson AB
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the names of the copyright holders nor the names of its
17 * contributors may be used to endorse or promote products derived from
18 * this software without specific prior written permission.
20 * Alternatively, this software may be distributed under the terms of the
21 * GNU General Public License ("GPL") version 2 as published by the Free
22 * Software Foundation.
24 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
25 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
28 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
29 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
30 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
31 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
32 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
33 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
34 * POSSIBILITY OF SUCH DAMAGE.
44 #include <linux/module.h>
46 /* Number of messages to send before rescheduling */
47 #define MAX_SEND_MSG_COUNT 25
48 #define MAX_RECV_MSG_COUNT 25
49 #define CF_CONNECTED 1
52 #define TIPC_SERVER_NAME_LEN 32
55 * struct tipc_topsrv - TIPC server structure
56 * @conn_idr: identifier set of connection
57 * @idr_lock: protect the connection identifier set
58 * @idr_in_use: amount of allocated identifier entry
59 * @net: network namspace instance
60 * @awork: accept work item
61 * @rcv_wq: receive workqueue
62 * @send_wq: send workqueue
63 * @max_rcvbuf_size: maximum permitted receive message length
64 * @listener: topsrv listener socket
69 spinlock_t idr_lock; /* for idr list */
72 struct work_struct awork;
73 struct workqueue_struct *rcv_wq;
74 struct workqueue_struct *send_wq;
76 struct socket *listener;
77 char name[TIPC_SERVER_NAME_LEN];
81 * struct tipc_conn - TIPC connection structure
82 * @kref: reference counter to connection object
83 * @conid: connection identifier
84 * @sock: socket handler associated with connection
85 * @flags: indicates connection state
86 * @server: pointer to connected server
87 * @sub_list: lsit to all pertaing subscriptions
88 * @sub_lock: lock protecting the subscription list
89 * @rwork: receive work item
90 * @outqueue: pointer to first outbound message in queue
91 * @outqueue_lock: control access to the outqueue
92 * @swork: send work item
99 struct tipc_topsrv *server;
100 struct list_head sub_list;
101 spinlock_t sub_lock; /* for subscription list */
102 struct work_struct rwork;
103 struct list_head outqueue;
104 spinlock_t outqueue_lock; /* for outqueue */
105 struct work_struct swork;
108 /* An entry waiting to be sent */
109 struct outqueue_entry {
111 struct tipc_event evt;
112 struct list_head list;
115 static void tipc_conn_recv_work(struct work_struct *work);
116 static void tipc_conn_send_work(struct work_struct *work);
117 static void tipc_topsrv_kern_evt(struct net *net, struct tipc_event *evt);
118 static void tipc_conn_delete_sub(struct tipc_conn *con, struct tipc_subscr *s);
120 static bool connected(struct tipc_conn *con)
122 return con && test_bit(CF_CONNECTED, &con->flags);
125 static void tipc_conn_kref_release(struct kref *kref)
127 struct tipc_conn *con = container_of(kref, struct tipc_conn, kref);
128 struct tipc_topsrv *s = con->server;
129 struct outqueue_entry *e, *safe;
131 spin_lock_bh(&s->idr_lock);
132 idr_remove(&s->conn_idr, con->conid);
134 spin_unlock_bh(&s->idr_lock);
136 sock_release(con->sock);
138 spin_lock_bh(&con->outqueue_lock);
139 list_for_each_entry_safe(e, safe, &con->outqueue, list) {
143 spin_unlock_bh(&con->outqueue_lock);
147 static void conn_put(struct tipc_conn *con)
149 kref_put(&con->kref, tipc_conn_kref_release);
152 static void conn_get(struct tipc_conn *con)
154 kref_get(&con->kref);
157 static void tipc_conn_close(struct tipc_conn *con)
159 struct sock *sk = con->sock->sk;
160 bool disconnect = false;
162 write_lock_bh(&sk->sk_callback_lock);
163 disconnect = test_and_clear_bit(CF_CONNECTED, &con->flags);
166 sk->sk_user_data = NULL;
167 tipc_conn_delete_sub(con, NULL);
169 write_unlock_bh(&sk->sk_callback_lock);
171 /* Handle concurrent calls from sending and receiving threads */
175 /* Don't flush pending works, -just let them expire */
176 kernel_sock_shutdown(con->sock, SHUT_RDWR);
181 static struct tipc_conn *tipc_conn_alloc(struct tipc_topsrv *s)
183 struct tipc_conn *con;
186 con = kzalloc(sizeof(*con), GFP_ATOMIC);
188 return ERR_PTR(-ENOMEM);
190 kref_init(&con->kref);
191 INIT_LIST_HEAD(&con->outqueue);
192 INIT_LIST_HEAD(&con->sub_list);
193 spin_lock_init(&con->outqueue_lock);
194 spin_lock_init(&con->sub_lock);
195 INIT_WORK(&con->swork, tipc_conn_send_work);
196 INIT_WORK(&con->rwork, tipc_conn_recv_work);
198 spin_lock_bh(&s->idr_lock);
199 ret = idr_alloc(&s->conn_idr, con, 0, 0, GFP_ATOMIC);
202 spin_unlock_bh(&s->idr_lock);
203 return ERR_PTR(-ENOMEM);
207 spin_unlock_bh(&s->idr_lock);
209 set_bit(CF_CONNECTED, &con->flags);
215 static struct tipc_conn *tipc_conn_lookup(struct tipc_topsrv *s, int conid)
217 struct tipc_conn *con;
219 spin_lock_bh(&s->idr_lock);
220 con = idr_find(&s->conn_idr, conid);
221 if (!connected(con) || !kref_get_unless_zero(&con->kref))
223 spin_unlock_bh(&s->idr_lock);
227 /* tipc_conn_delete_sub - delete a specific or all subscriptions
228 * for a given subscriber
230 static void tipc_conn_delete_sub(struct tipc_conn *con, struct tipc_subscr *s)
232 struct tipc_net *tn = tipc_net(con->server->net);
233 struct list_head *sub_list = &con->sub_list;
234 struct tipc_subscription *sub, *tmp;
236 spin_lock_bh(&con->sub_lock);
237 list_for_each_entry_safe(sub, tmp, sub_list, sub_list) {
238 if (!s || !memcmp(s, &sub->evt.s, sizeof(*s))) {
239 tipc_sub_unsubscribe(sub);
240 atomic_dec(&tn->subscription_count);
245 spin_unlock_bh(&con->sub_lock);
248 static void tipc_conn_send_to_sock(struct tipc_conn *con)
250 struct list_head *queue = &con->outqueue;
251 struct tipc_topsrv *srv = con->server;
252 struct outqueue_entry *e;
253 struct tipc_event *evt;
259 spin_lock_bh(&con->outqueue_lock);
261 while (!list_empty(queue)) {
262 e = list_first_entry(queue, struct outqueue_entry, list);
264 spin_unlock_bh(&con->outqueue_lock);
267 tipc_conn_delete_sub(con, &evt->s);
269 memset(&msg, 0, sizeof(msg));
270 msg.msg_flags = MSG_DONTWAIT;
272 iov.iov_len = sizeof(*evt);
276 ret = kernel_sendmsg(con->sock, &msg, &iov,
278 if (ret == -EWOULDBLOCK || ret == 0) {
281 } else if (ret < 0) {
282 return tipc_conn_close(con);
285 tipc_topsrv_kern_evt(srv->net, evt);
288 /* Don't starve users filling buffers */
289 if (++count >= MAX_SEND_MSG_COUNT) {
293 spin_lock_bh(&con->outqueue_lock);
297 spin_unlock_bh(&con->outqueue_lock);
300 static void tipc_conn_send_work(struct work_struct *work)
302 struct tipc_conn *con = container_of(work, struct tipc_conn, swork);
305 tipc_conn_send_to_sock(con);
310 /* tipc_topsrv_queue_evt() - interrupt level call from a subscription instance
311 * The queued work is launched into tipc_conn_send_work()->tipc_conn_send_to_sock()
313 void tipc_topsrv_queue_evt(struct net *net, int conid,
314 u32 event, struct tipc_event *evt)
316 struct tipc_topsrv *srv = tipc_topsrv(net);
317 struct outqueue_entry *e;
318 struct tipc_conn *con;
320 con = tipc_conn_lookup(srv, conid);
327 e = kmalloc(sizeof(*e), GFP_ATOMIC);
330 e->inactive = (event == TIPC_SUBSCR_TIMEOUT);
331 memcpy(&e->evt, evt, sizeof(*evt));
332 spin_lock_bh(&con->outqueue_lock);
333 list_add_tail(&e->list, &con->outqueue);
334 spin_unlock_bh(&con->outqueue_lock);
336 if (queue_work(srv->send_wq, &con->swork))
342 /* tipc_conn_write_space - interrupt callback after a sendmsg EAGAIN
343 * Indicates that there now is more space in the send buffer
344 * The queued work is launched into tipc_send_work()->tipc_conn_send_to_sock()
346 static void tipc_conn_write_space(struct sock *sk)
348 struct tipc_conn *con;
350 read_lock_bh(&sk->sk_callback_lock);
351 con = sk->sk_user_data;
352 if (connected(con)) {
354 if (!queue_work(con->server->send_wq, &con->swork))
357 read_unlock_bh(&sk->sk_callback_lock);
360 static int tipc_conn_rcv_sub(struct tipc_topsrv *srv,
361 struct tipc_conn *con,
362 struct tipc_subscr *s)
364 struct tipc_net *tn = tipc_net(srv->net);
365 struct tipc_subscription *sub;
367 if (tipc_sub_read(s, filter) & TIPC_SUB_CANCEL) {
368 tipc_conn_delete_sub(con, s);
371 if (atomic_read(&tn->subscription_count) >= TIPC_MAX_SUBSCR) {
372 pr_warn("Subscription rejected, max (%u)\n", TIPC_MAX_SUBSCR);
375 sub = tipc_sub_subscribe(srv->net, s, con->conid);
378 atomic_inc(&tn->subscription_count);
379 spin_lock_bh(&con->sub_lock);
380 list_add(&sub->sub_list, &con->sub_list);
381 spin_unlock_bh(&con->sub_lock);
385 static int tipc_conn_rcv_from_sock(struct tipc_conn *con)
387 struct tipc_topsrv *srv = con->server;
388 struct sock *sk = con->sock->sk;
389 struct msghdr msg = {};
390 struct tipc_subscr s;
395 iov.iov_len = sizeof(s);
397 iov_iter_kvec(&msg.msg_iter, READ, &iov, 1, iov.iov_len);
398 ret = sock_recvmsg(con->sock, &msg, MSG_DONTWAIT);
399 if (ret == -EWOULDBLOCK)
402 read_lock_bh(&sk->sk_callback_lock);
403 ret = tipc_conn_rcv_sub(srv, con, &s);
404 read_unlock_bh(&sk->sk_callback_lock);
407 tipc_conn_close(con);
412 static void tipc_conn_recv_work(struct work_struct *work)
414 struct tipc_conn *con = container_of(work, struct tipc_conn, rwork);
417 while (connected(con)) {
418 if (tipc_conn_rcv_from_sock(con))
421 /* Don't flood Rx machine */
422 if (++count >= MAX_RECV_MSG_COUNT) {
430 /* tipc_conn_data_ready - interrupt callback indicating the socket has data
431 * The queued work is launched into tipc_recv_work()->tipc_conn_rcv_from_sock()
433 static void tipc_conn_data_ready(struct sock *sk)
435 struct tipc_conn *con;
437 read_lock_bh(&sk->sk_callback_lock);
438 con = sk->sk_user_data;
439 if (connected(con)) {
441 if (!queue_work(con->server->rcv_wq, &con->rwork))
444 read_unlock_bh(&sk->sk_callback_lock);
447 static void tipc_topsrv_accept(struct work_struct *work)
449 struct tipc_topsrv *srv = container_of(work, struct tipc_topsrv, awork);
450 struct socket *lsock = srv->listener;
451 struct socket *newsock;
452 struct tipc_conn *con;
457 ret = kernel_accept(lsock, &newsock, O_NONBLOCK);
460 con = tipc_conn_alloc(srv);
463 sock_release(newsock);
466 /* Register callbacks */
468 write_lock_bh(&newsk->sk_callback_lock);
469 newsk->sk_data_ready = tipc_conn_data_ready;
470 newsk->sk_write_space = tipc_conn_write_space;
471 newsk->sk_user_data = con;
473 write_unlock_bh(&newsk->sk_callback_lock);
475 /* Wake up receive process in case of 'SYN+' message */
476 newsk->sk_data_ready(newsk);
480 /* tipc_toprsv_listener_data_ready - interrupt callback with connection request
481 * The queued job is launched into tipc_topsrv_accept()
483 static void tipc_topsrv_listener_data_ready(struct sock *sk)
485 struct tipc_topsrv *srv;
487 read_lock_bh(&sk->sk_callback_lock);
488 srv = sk->sk_user_data;
490 queue_work(srv->rcv_wq, &srv->awork);
491 read_unlock_bh(&sk->sk_callback_lock);
494 static int tipc_topsrv_create_listener(struct tipc_topsrv *srv)
496 int imp = TIPC_CRITICAL_IMPORTANCE;
497 struct socket *lsock = NULL;
498 struct sockaddr_tipc saddr;
502 rc = sock_create_kern(srv->net, AF_TIPC, SOCK_SEQPACKET, 0, &lsock);
506 srv->listener = lsock;
508 write_lock_bh(&sk->sk_callback_lock);
509 sk->sk_data_ready = tipc_topsrv_listener_data_ready;
510 sk->sk_user_data = srv;
511 write_unlock_bh(&sk->sk_callback_lock);
513 rc = kernel_setsockopt(lsock, SOL_TIPC, TIPC_IMPORTANCE,
514 (char *)&imp, sizeof(imp));
518 saddr.family = AF_TIPC;
519 saddr.addrtype = TIPC_ADDR_NAMESEQ;
520 saddr.addr.nameseq.type = TIPC_TOP_SRV;
521 saddr.addr.nameseq.lower = TIPC_TOP_SRV;
522 saddr.addr.nameseq.upper = TIPC_TOP_SRV;
523 saddr.scope = TIPC_NODE_SCOPE;
525 rc = kernel_bind(lsock, (struct sockaddr *)&saddr, sizeof(saddr));
528 rc = kernel_listen(lsock, 0);
532 /* As server's listening socket owner and creator is the same module,
533 * we have to decrease TIPC module reference count to guarantee that
534 * it remains zero after the server socket is created, otherwise,
535 * executing "rmmod" command is unable to make TIPC module deleted
536 * after TIPC module is inserted successfully.
538 * However, the reference count is ever increased twice in
539 * sock_create_kern(): one is to increase the reference count of owner
540 * of TIPC socket's proto_ops struct; another is to increment the
541 * reference count of owner of TIPC proto struct. Therefore, we must
542 * decrement the module reference count twice to ensure that it keeps
543 * zero after server's listening socket is created. Of course, we
544 * must bump the module reference count twice as well before the socket
547 module_put(lsock->ops->owner);
548 module_put(sk->sk_prot_creator->owner);
556 bool tipc_topsrv_kern_subscr(struct net *net, u32 port, u32 type, u32 lower,
557 u32 upper, u32 filter, int *conid)
559 struct tipc_subscr sub;
560 struct tipc_conn *con;
564 sub.seq.lower = lower;
565 sub.seq.upper = upper;
566 sub.timeout = TIPC_WAIT_FOREVER;
568 *(u32 *)&sub.usr_handle = port;
570 con = tipc_conn_alloc(tipc_topsrv(net));
576 rc = tipc_conn_rcv_sub(tipc_topsrv(net), con, &sub);
583 void tipc_topsrv_kern_unsubscr(struct net *net, int conid)
585 struct tipc_conn *con;
587 con = tipc_conn_lookup(tipc_topsrv(net), conid);
591 test_and_clear_bit(CF_CONNECTED, &con->flags);
592 tipc_conn_delete_sub(con, NULL);
597 static void tipc_topsrv_kern_evt(struct net *net, struct tipc_event *evt)
599 u32 port = *(u32 *)&evt->s.usr_handle;
600 u32 self = tipc_own_addr(net);
601 struct sk_buff_head evtq;
604 skb = tipc_msg_create(TOP_SRV, 0, INT_H_SIZE, sizeof(*evt),
605 self, self, port, port, 0);
608 msg_set_dest_droppable(buf_msg(skb), true);
609 memcpy(msg_data(buf_msg(skb)), evt, sizeof(*evt));
610 skb_queue_head_init(&evtq);
611 __skb_queue_tail(&evtq, skb);
612 tipc_sk_rcv(net, &evtq);
615 static int tipc_topsrv_work_start(struct tipc_topsrv *s)
617 s->rcv_wq = alloc_ordered_workqueue("tipc_rcv", 0);
619 pr_err("can't start tipc receive workqueue\n");
623 s->send_wq = alloc_ordered_workqueue("tipc_send", 0);
625 pr_err("can't start tipc send workqueue\n");
626 destroy_workqueue(s->rcv_wq);
633 static void tipc_topsrv_work_stop(struct tipc_topsrv *s)
635 destroy_workqueue(s->rcv_wq);
636 destroy_workqueue(s->send_wq);
639 int tipc_topsrv_start(struct net *net)
641 struct tipc_net *tn = tipc_net(net);
642 const char name[] = "topology_server";
643 struct tipc_topsrv *srv;
646 srv = kzalloc(sizeof(*srv), GFP_ATOMIC);
651 srv->max_rcvbuf_size = sizeof(struct tipc_subscr);
652 INIT_WORK(&srv->awork, tipc_topsrv_accept);
654 strscpy(srv->name, name, sizeof(srv->name));
656 atomic_set(&tn->subscription_count, 0);
658 spin_lock_init(&srv->idr_lock);
659 idr_init(&srv->conn_idr);
662 ret = tipc_topsrv_work_start(srv);
666 ret = tipc_topsrv_create_listener(srv);
668 tipc_topsrv_work_stop(srv);
673 void tipc_topsrv_stop(struct net *net)
675 struct tipc_topsrv *srv = tipc_topsrv(net);
676 struct socket *lsock = srv->listener;
677 struct tipc_conn *con;
680 spin_lock_bh(&srv->idr_lock);
681 for (id = 0; srv->idr_in_use; id++) {
682 con = idr_find(&srv->conn_idr, id);
684 spin_unlock_bh(&srv->idr_lock);
685 tipc_conn_close(con);
686 spin_lock_bh(&srv->idr_lock);
689 __module_get(lsock->ops->owner);
690 __module_get(lsock->sk->sk_prot_creator->owner);
691 srv->listener = NULL;
692 spin_unlock_bh(&srv->idr_lock);
694 tipc_topsrv_work_stop(srv);
695 idr_destroy(&srv->conn_idr);