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.
45 #include <linux/module.h>
47 /* Number of messages to send before rescheduling */
48 #define MAX_SEND_MSG_COUNT 25
49 #define MAX_RECV_MSG_COUNT 25
50 #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 * @listener: topsrv listener socket
68 spinlock_t idr_lock; /* for idr list */
71 struct work_struct awork;
72 struct workqueue_struct *rcv_wq;
73 struct workqueue_struct *send_wq;
74 struct socket *listener;
75 char name[TIPC_SERVER_NAME_LEN];
79 * struct tipc_conn - TIPC connection structure
80 * @kref: reference counter to connection object
81 * @conid: connection identifier
82 * @sock: socket handler associated with connection
83 * @flags: indicates connection state
84 * @server: pointer to connected server
85 * @sub_list: lsit to all pertaing subscriptions
86 * @sub_lock: lock protecting the subscription list
87 * @rwork: receive work item
88 * @outqueue: pointer to first outbound message in queue
89 * @outqueue_lock: control access to the outqueue
90 * @swork: send work item
97 struct tipc_topsrv *server;
98 struct list_head sub_list;
99 spinlock_t sub_lock; /* for subscription list */
100 struct work_struct rwork;
101 struct list_head outqueue;
102 spinlock_t outqueue_lock; /* for outqueue */
103 struct work_struct swork;
106 /* An entry waiting to be sent */
107 struct outqueue_entry {
109 struct tipc_event evt;
110 struct list_head list;
113 static void tipc_conn_recv_work(struct work_struct *work);
114 static void tipc_conn_send_work(struct work_struct *work);
115 static void tipc_topsrv_kern_evt(struct net *net, struct tipc_event *evt);
116 static void tipc_conn_delete_sub(struct tipc_conn *con, struct tipc_subscr *s);
118 static bool connected(struct tipc_conn *con)
120 return con && test_bit(CF_CONNECTED, &con->flags);
123 static void tipc_conn_kref_release(struct kref *kref)
125 struct tipc_conn *con = container_of(kref, struct tipc_conn, kref);
126 struct tipc_topsrv *s = con->server;
127 struct outqueue_entry *e, *safe;
129 spin_lock_bh(&s->idr_lock);
130 idr_remove(&s->conn_idr, con->conid);
132 spin_unlock_bh(&s->idr_lock);
134 sock_release(con->sock);
136 spin_lock_bh(&con->outqueue_lock);
137 list_for_each_entry_safe(e, safe, &con->outqueue, list) {
141 spin_unlock_bh(&con->outqueue_lock);
145 static void conn_put(struct tipc_conn *con)
147 kref_put(&con->kref, tipc_conn_kref_release);
150 static void conn_get(struct tipc_conn *con)
152 kref_get(&con->kref);
155 static void tipc_conn_close(struct tipc_conn *con)
157 struct sock *sk = con->sock->sk;
158 bool disconnect = false;
160 write_lock_bh(&sk->sk_callback_lock);
161 disconnect = test_and_clear_bit(CF_CONNECTED, &con->flags);
164 sk->sk_user_data = NULL;
165 tipc_conn_delete_sub(con, NULL);
167 write_unlock_bh(&sk->sk_callback_lock);
169 /* Handle concurrent calls from sending and receiving threads */
173 /* Don't flush pending works, -just let them expire */
174 kernel_sock_shutdown(con->sock, SHUT_RDWR);
179 static struct tipc_conn *tipc_conn_alloc(struct tipc_topsrv *s, struct socket *sock)
181 struct tipc_conn *con;
184 con = kzalloc(sizeof(*con), GFP_ATOMIC);
186 return ERR_PTR(-ENOMEM);
188 kref_init(&con->kref);
189 INIT_LIST_HEAD(&con->outqueue);
190 INIT_LIST_HEAD(&con->sub_list);
191 spin_lock_init(&con->outqueue_lock);
192 spin_lock_init(&con->sub_lock);
193 INIT_WORK(&con->swork, tipc_conn_send_work);
194 INIT_WORK(&con->rwork, tipc_conn_recv_work);
196 spin_lock_bh(&s->idr_lock);
197 ret = idr_alloc(&s->conn_idr, con, 0, 0, GFP_ATOMIC);
200 spin_unlock_bh(&s->idr_lock);
201 return ERR_PTR(-ENOMEM);
206 set_bit(CF_CONNECTED, &con->flags);
209 spin_unlock_bh(&s->idr_lock);
214 static struct tipc_conn *tipc_conn_lookup(struct tipc_topsrv *s, int conid)
216 struct tipc_conn *con;
218 spin_lock_bh(&s->idr_lock);
219 con = idr_find(&s->conn_idr, conid);
220 if (!connected(con) || !kref_get_unless_zero(&con->kref))
222 spin_unlock_bh(&s->idr_lock);
226 /* tipc_conn_delete_sub - delete a specific or all subscriptions
227 * for a given subscriber
229 static void tipc_conn_delete_sub(struct tipc_conn *con, struct tipc_subscr *s)
231 struct tipc_net *tn = tipc_net(con->server->net);
232 struct list_head *sub_list = &con->sub_list;
233 struct tipc_subscription *sub, *tmp;
235 spin_lock_bh(&con->sub_lock);
236 list_for_each_entry_safe(sub, tmp, sub_list, sub_list) {
237 if (!s || !memcmp(s, &sub->evt.s, sizeof(*s))) {
238 tipc_sub_unsubscribe(sub);
239 atomic_dec(&tn->subscription_count);
244 spin_unlock_bh(&con->sub_lock);
247 static void tipc_conn_send_to_sock(struct tipc_conn *con)
249 struct list_head *queue = &con->outqueue;
250 struct tipc_topsrv *srv = con->server;
251 struct outqueue_entry *e;
252 struct tipc_event *evt;
258 spin_lock_bh(&con->outqueue_lock);
260 while (!list_empty(queue)) {
261 e = list_first_entry(queue, struct outqueue_entry, list);
263 spin_unlock_bh(&con->outqueue_lock);
266 tipc_conn_delete_sub(con, &evt->s);
268 memset(&msg, 0, sizeof(msg));
269 msg.msg_flags = MSG_DONTWAIT;
271 iov.iov_len = sizeof(*evt);
275 ret = kernel_sendmsg(con->sock, &msg, &iov,
277 if (ret == -EWOULDBLOCK || ret == 0) {
280 } else if (ret < 0) {
281 return tipc_conn_close(con);
284 tipc_topsrv_kern_evt(srv->net, evt);
287 /* Don't starve users filling buffers */
288 if (++count >= MAX_SEND_MSG_COUNT) {
292 spin_lock_bh(&con->outqueue_lock);
296 spin_unlock_bh(&con->outqueue_lock);
299 static void tipc_conn_send_work(struct work_struct *work)
301 struct tipc_conn *con = container_of(work, struct tipc_conn, swork);
304 tipc_conn_send_to_sock(con);
309 /* tipc_topsrv_queue_evt() - interrupt level call from a subscription instance
310 * The queued work is launched into tipc_conn_send_work()->tipc_conn_send_to_sock()
312 void tipc_topsrv_queue_evt(struct net *net, int conid,
313 u32 event, struct tipc_event *evt)
315 struct tipc_topsrv *srv = tipc_topsrv(net);
316 struct outqueue_entry *e;
317 struct tipc_conn *con;
319 con = tipc_conn_lookup(srv, conid);
326 e = kmalloc(sizeof(*e), GFP_ATOMIC);
329 e->inactive = (event == TIPC_SUBSCR_TIMEOUT);
330 memcpy(&e->evt, evt, sizeof(*evt));
331 spin_lock_bh(&con->outqueue_lock);
332 list_add_tail(&e->list, &con->outqueue);
333 spin_unlock_bh(&con->outqueue_lock);
335 if (queue_work(srv->send_wq, &con->swork))
341 /* tipc_conn_write_space - interrupt callback after a sendmsg EAGAIN
342 * Indicates that there now is more space in the send buffer
343 * The queued work is launched into tipc_send_work()->tipc_conn_send_to_sock()
345 static void tipc_conn_write_space(struct sock *sk)
347 struct tipc_conn *con;
349 read_lock_bh(&sk->sk_callback_lock);
350 con = sk->sk_user_data;
351 if (connected(con)) {
353 if (!queue_work(con->server->send_wq, &con->swork))
356 read_unlock_bh(&sk->sk_callback_lock);
359 static int tipc_conn_rcv_sub(struct tipc_topsrv *srv,
360 struct tipc_conn *con,
361 struct tipc_subscr *s)
363 struct tipc_net *tn = tipc_net(srv->net);
364 struct tipc_subscription *sub;
365 u32 s_filter = tipc_sub_read(s, filter);
367 if (s_filter & TIPC_SUB_CANCEL) {
368 tipc_sub_write(s, filter, s_filter & ~TIPC_SUB_CANCEL);
369 tipc_conn_delete_sub(con, s);
372 if (atomic_read(&tn->subscription_count) >= TIPC_MAX_SUBSCR) {
373 pr_warn("Subscription rejected, max (%u)\n", TIPC_MAX_SUBSCR);
376 sub = tipc_sub_subscribe(srv->net, s, con->conid);
379 atomic_inc(&tn->subscription_count);
380 spin_lock_bh(&con->sub_lock);
381 list_add(&sub->sub_list, &con->sub_list);
382 spin_unlock_bh(&con->sub_lock);
386 static int tipc_conn_rcv_from_sock(struct tipc_conn *con)
388 struct tipc_topsrv *srv = con->server;
389 struct sock *sk = con->sock->sk;
390 struct msghdr msg = {};
391 struct tipc_subscr s;
396 iov.iov_len = sizeof(s);
398 iov_iter_kvec(&msg.msg_iter, READ, &iov, 1, iov.iov_len);
399 ret = sock_recvmsg(con->sock, &msg, MSG_DONTWAIT);
400 if (ret == -EWOULDBLOCK)
402 if (ret == sizeof(s)) {
403 read_lock_bh(&sk->sk_callback_lock);
404 /* RACE: the connection can be closed in the meantime */
405 if (likely(connected(con)))
406 ret = tipc_conn_rcv_sub(srv, con, &s);
407 read_unlock_bh(&sk->sk_callback_lock);
412 tipc_conn_close(con);
416 static void tipc_conn_recv_work(struct work_struct *work)
418 struct tipc_conn *con = container_of(work, struct tipc_conn, rwork);
421 while (connected(con)) {
422 if (tipc_conn_rcv_from_sock(con))
425 /* Don't flood Rx machine */
426 if (++count >= MAX_RECV_MSG_COUNT) {
434 /* tipc_conn_data_ready - interrupt callback indicating the socket has data
435 * The queued work is launched into tipc_recv_work()->tipc_conn_rcv_from_sock()
437 static void tipc_conn_data_ready(struct sock *sk)
439 struct tipc_conn *con;
441 read_lock_bh(&sk->sk_callback_lock);
442 con = sk->sk_user_data;
443 if (connected(con)) {
445 if (!queue_work(con->server->rcv_wq, &con->rwork))
448 read_unlock_bh(&sk->sk_callback_lock);
451 static void tipc_topsrv_accept(struct work_struct *work)
453 struct tipc_topsrv *srv = container_of(work, struct tipc_topsrv, awork);
454 struct socket *newsock, *lsock;
455 struct tipc_conn *con;
459 spin_lock_bh(&srv->idr_lock);
460 if (!srv->listener) {
461 spin_unlock_bh(&srv->idr_lock);
464 lsock = srv->listener;
465 spin_unlock_bh(&srv->idr_lock);
468 ret = kernel_accept(lsock, &newsock, O_NONBLOCK);
471 con = tipc_conn_alloc(srv, newsock);
474 sock_release(newsock);
477 /* Register callbacks */
479 write_lock_bh(&newsk->sk_callback_lock);
480 newsk->sk_data_ready = tipc_conn_data_ready;
481 newsk->sk_write_space = tipc_conn_write_space;
482 newsk->sk_user_data = con;
483 write_unlock_bh(&newsk->sk_callback_lock);
485 /* Wake up receive process in case of 'SYN+' message */
486 newsk->sk_data_ready(newsk);
490 /* tipc_topsrv_listener_data_ready - interrupt callback with connection request
491 * The queued job is launched into tipc_topsrv_accept()
493 static void tipc_topsrv_listener_data_ready(struct sock *sk)
495 struct tipc_topsrv *srv;
497 read_lock_bh(&sk->sk_callback_lock);
498 srv = sk->sk_user_data;
500 queue_work(srv->rcv_wq, &srv->awork);
501 read_unlock_bh(&sk->sk_callback_lock);
504 static int tipc_topsrv_create_listener(struct tipc_topsrv *srv)
506 struct socket *lsock = NULL;
507 struct sockaddr_tipc saddr;
511 rc = sock_create_kern(srv->net, AF_TIPC, SOCK_SEQPACKET, 0, &lsock);
515 srv->listener = lsock;
517 write_lock_bh(&sk->sk_callback_lock);
518 sk->sk_data_ready = tipc_topsrv_listener_data_ready;
519 sk->sk_user_data = srv;
520 write_unlock_bh(&sk->sk_callback_lock);
523 rc = tsk_set_importance(sk, TIPC_CRITICAL_IMPORTANCE);
528 saddr.family = AF_TIPC;
529 saddr.addrtype = TIPC_SERVICE_RANGE;
530 saddr.addr.nameseq.type = TIPC_TOP_SRV;
531 saddr.addr.nameseq.lower = TIPC_TOP_SRV;
532 saddr.addr.nameseq.upper = TIPC_TOP_SRV;
533 saddr.scope = TIPC_NODE_SCOPE;
535 rc = tipc_sk_bind(lsock, (struct sockaddr *)&saddr, sizeof(saddr));
538 rc = kernel_listen(lsock, 0);
542 /* As server's listening socket owner and creator is the same module,
543 * we have to decrease TIPC module reference count to guarantee that
544 * it remains zero after the server socket is created, otherwise,
545 * executing "rmmod" command is unable to make TIPC module deleted
546 * after TIPC module is inserted successfully.
548 * However, the reference count is ever increased twice in
549 * sock_create_kern(): one is to increase the reference count of owner
550 * of TIPC socket's proto_ops struct; another is to increment the
551 * reference count of owner of TIPC proto struct. Therefore, we must
552 * decrement the module reference count twice to ensure that it keeps
553 * zero after server's listening socket is created. Of course, we
554 * must bump the module reference count twice as well before the socket
557 module_put(lsock->ops->owner);
558 module_put(sk->sk_prot_creator->owner);
566 bool tipc_topsrv_kern_subscr(struct net *net, u32 port, u32 type, u32 lower,
567 u32 upper, u32 filter, int *conid)
569 struct tipc_subscr sub;
570 struct tipc_conn *con;
574 sub.seq.lower = lower;
575 sub.seq.upper = upper;
576 sub.timeout = TIPC_WAIT_FOREVER;
578 *(u64 *)&sub.usr_handle = (u64)port;
580 con = tipc_conn_alloc(tipc_topsrv(net), NULL);
585 rc = tipc_conn_rcv_sub(tipc_topsrv(net), con, &sub);
592 void tipc_topsrv_kern_unsubscr(struct net *net, int conid)
594 struct tipc_conn *con;
596 con = tipc_conn_lookup(tipc_topsrv(net), conid);
600 test_and_clear_bit(CF_CONNECTED, &con->flags);
601 tipc_conn_delete_sub(con, NULL);
606 static void tipc_topsrv_kern_evt(struct net *net, struct tipc_event *evt)
608 u32 port = *(u32 *)&evt->s.usr_handle;
609 u32 self = tipc_own_addr(net);
610 struct sk_buff_head evtq;
613 skb = tipc_msg_create(TOP_SRV, 0, INT_H_SIZE, sizeof(*evt),
614 self, self, port, port, 0);
617 msg_set_dest_droppable(buf_msg(skb), true);
618 memcpy(msg_data(buf_msg(skb)), evt, sizeof(*evt));
619 skb_queue_head_init(&evtq);
620 __skb_queue_tail(&evtq, skb);
621 tipc_loopback_trace(net, &evtq);
622 tipc_sk_rcv(net, &evtq);
625 static int tipc_topsrv_work_start(struct tipc_topsrv *s)
627 s->rcv_wq = alloc_ordered_workqueue("tipc_rcv", 0);
629 pr_err("can't start tipc receive workqueue\n");
633 s->send_wq = alloc_ordered_workqueue("tipc_send", 0);
635 pr_err("can't start tipc send workqueue\n");
636 destroy_workqueue(s->rcv_wq);
643 static void tipc_topsrv_work_stop(struct tipc_topsrv *s)
645 destroy_workqueue(s->rcv_wq);
646 destroy_workqueue(s->send_wq);
649 static int tipc_topsrv_start(struct net *net)
651 struct tipc_net *tn = tipc_net(net);
652 const char name[] = "topology_server";
653 struct tipc_topsrv *srv;
656 srv = kzalloc(sizeof(*srv), GFP_ATOMIC);
661 INIT_WORK(&srv->awork, tipc_topsrv_accept);
663 strscpy(srv->name, name, sizeof(srv->name));
665 atomic_set(&tn->subscription_count, 0);
667 spin_lock_init(&srv->idr_lock);
668 idr_init(&srv->conn_idr);
671 ret = tipc_topsrv_work_start(srv);
675 ret = tipc_topsrv_create_listener(srv);
682 tipc_topsrv_work_stop(srv);
688 static void tipc_topsrv_stop(struct net *net)
690 struct tipc_topsrv *srv = tipc_topsrv(net);
691 struct socket *lsock = srv->listener;
692 struct tipc_conn *con;
695 spin_lock_bh(&srv->idr_lock);
696 for (id = 0; srv->idr_in_use; id++) {
697 con = idr_find(&srv->conn_idr, id);
699 spin_unlock_bh(&srv->idr_lock);
700 tipc_conn_close(con);
701 spin_lock_bh(&srv->idr_lock);
704 __module_get(lsock->ops->owner);
705 __module_get(lsock->sk->sk_prot_creator->owner);
706 srv->listener = NULL;
707 spin_unlock_bh(&srv->idr_lock);
709 tipc_topsrv_work_stop(srv);
711 idr_destroy(&srv->conn_idr);
715 int __net_init tipc_topsrv_init_net(struct net *net)
717 return tipc_topsrv_start(net);
720 void __net_exit tipc_topsrv_exit_net(struct net *net)
722 tipc_topsrv_stop(net);