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 * @rcvbuf_cache: memory cache of server receive buffer
61 * @rcv_wq: receive workqueue
62 * @send_wq: send workqueue
63 * @max_rcvbuf_size: maximum permitted receive message length
64 * @tipc_conn_new: callback will be called when new connection is incoming
65 * @tipc_conn_release: callback will be called before releasing the connection
66 * @tipc_conn_recvmsg: callback will be called when message arrives
68 * @imp: message importance
73 spinlock_t idr_lock; /* for idr list */
76 struct work_struct awork;
77 struct workqueue_struct *rcv_wq;
78 struct workqueue_struct *send_wq;
80 struct socket *listener;
81 char name[TIPC_SERVER_NAME_LEN];
85 * struct tipc_conn - TIPC connection structure
86 * @kref: reference counter to connection object
87 * @conid: connection identifier
88 * @sock: socket handler associated with connection
89 * @flags: indicates connection state
90 * @server: pointer to connected server
91 * @sub_list: lsit to all pertaing subscriptions
92 * @sub_lock: lock protecting the subscription list
93 * @outqueue_lock: control access to the outqueue
94 * @rwork: receive work item
95 * @rx_action: what to do when connection socket is active
96 * @outqueue: pointer to first outbound message in queue
97 * @outqueue_lock: control access to the outqueue
98 * @swork: send work item
105 struct tipc_topsrv *server;
106 struct list_head sub_list;
107 spinlock_t sub_lock; /* for subscription list */
108 struct work_struct rwork;
109 struct list_head outqueue;
110 spinlock_t outqueue_lock; /* for outqueue */
111 struct work_struct swork;
114 /* An entry waiting to be sent */
115 struct outqueue_entry {
117 struct tipc_event evt;
118 struct list_head list;
121 static void tipc_conn_recv_work(struct work_struct *work);
122 static void tipc_conn_send_work(struct work_struct *work);
123 static void tipc_topsrv_kern_evt(struct net *net, struct tipc_event *evt);
124 static void tipc_conn_delete_sub(struct tipc_conn *con, struct tipc_subscr *s);
126 static bool connected(struct tipc_conn *con)
128 return con && test_bit(CF_CONNECTED, &con->flags);
131 static void tipc_conn_kref_release(struct kref *kref)
133 struct tipc_conn *con = container_of(kref, struct tipc_conn, kref);
134 struct tipc_topsrv *s = con->server;
135 struct outqueue_entry *e, *safe;
137 spin_lock_bh(&s->idr_lock);
138 idr_remove(&s->conn_idr, con->conid);
140 spin_unlock_bh(&s->idr_lock);
142 sock_release(con->sock);
144 spin_lock_bh(&con->outqueue_lock);
145 list_for_each_entry_safe(e, safe, &con->outqueue, list) {
149 spin_unlock_bh(&con->outqueue_lock);
153 static void conn_put(struct tipc_conn *con)
155 kref_put(&con->kref, tipc_conn_kref_release);
158 static void conn_get(struct tipc_conn *con)
160 kref_get(&con->kref);
163 static void tipc_conn_close(struct tipc_conn *con)
165 struct sock *sk = con->sock->sk;
166 bool disconnect = false;
168 write_lock_bh(&sk->sk_callback_lock);
169 disconnect = test_and_clear_bit(CF_CONNECTED, &con->flags);
172 sk->sk_user_data = NULL;
173 tipc_conn_delete_sub(con, NULL);
175 write_unlock_bh(&sk->sk_callback_lock);
177 /* Handle concurrent calls from sending and receiving threads */
181 /* Don't flush pending works, -just let them expire */
182 kernel_sock_shutdown(con->sock, SHUT_RDWR);
187 static struct tipc_conn *tipc_conn_alloc(struct tipc_topsrv *s)
189 struct tipc_conn *con;
192 con = kzalloc(sizeof(*con), GFP_ATOMIC);
194 return ERR_PTR(-ENOMEM);
196 kref_init(&con->kref);
197 INIT_LIST_HEAD(&con->outqueue);
198 INIT_LIST_HEAD(&con->sub_list);
199 spin_lock_init(&con->outqueue_lock);
200 spin_lock_init(&con->sub_lock);
201 INIT_WORK(&con->swork, tipc_conn_send_work);
202 INIT_WORK(&con->rwork, tipc_conn_recv_work);
204 spin_lock_bh(&s->idr_lock);
205 ret = idr_alloc(&s->conn_idr, con, 0, 0, GFP_ATOMIC);
208 spin_unlock_bh(&s->idr_lock);
209 return ERR_PTR(-ENOMEM);
213 spin_unlock_bh(&s->idr_lock);
215 set_bit(CF_CONNECTED, &con->flags);
221 static struct tipc_conn *tipc_conn_lookup(struct tipc_topsrv *s, int conid)
223 struct tipc_conn *con;
225 spin_lock_bh(&s->idr_lock);
226 con = idr_find(&s->conn_idr, conid);
227 if (!connected(con) || !kref_get_unless_zero(&con->kref))
229 spin_unlock_bh(&s->idr_lock);
233 /* tipc_conn_delete_sub - delete a specific or all subscriptions
234 * for a given subscriber
236 static void tipc_conn_delete_sub(struct tipc_conn *con, struct tipc_subscr *s)
238 struct tipc_net *tn = tipc_net(con->server->net);
239 struct list_head *sub_list = &con->sub_list;
240 struct tipc_subscription *sub, *tmp;
242 spin_lock_bh(&con->sub_lock);
243 list_for_each_entry_safe(sub, tmp, sub_list, sub_list) {
244 if (!s || !memcmp(s, &sub->evt.s, sizeof(*s))) {
245 tipc_sub_unsubscribe(sub);
246 atomic_dec(&tn->subscription_count);
251 spin_unlock_bh(&con->sub_lock);
254 static void tipc_conn_send_to_sock(struct tipc_conn *con)
256 struct list_head *queue = &con->outqueue;
257 struct tipc_topsrv *srv = con->server;
258 struct outqueue_entry *e;
259 struct tipc_event *evt;
265 spin_lock_bh(&con->outqueue_lock);
267 while (!list_empty(queue)) {
268 e = list_first_entry(queue, struct outqueue_entry, list);
270 spin_unlock_bh(&con->outqueue_lock);
273 tipc_conn_delete_sub(con, &evt->s);
275 memset(&msg, 0, sizeof(msg));
276 msg.msg_flags = MSG_DONTWAIT;
278 iov.iov_len = sizeof(*evt);
282 ret = kernel_sendmsg(con->sock, &msg, &iov,
284 if (ret == -EWOULDBLOCK || ret == 0) {
287 } else if (ret < 0) {
288 return tipc_conn_close(con);
291 tipc_topsrv_kern_evt(srv->net, evt);
294 /* Don't starve users filling buffers */
295 if (++count >= MAX_SEND_MSG_COUNT) {
299 spin_lock_bh(&con->outqueue_lock);
303 spin_unlock_bh(&con->outqueue_lock);
306 static void tipc_conn_send_work(struct work_struct *work)
308 struct tipc_conn *con = container_of(work, struct tipc_conn, swork);
311 tipc_conn_send_to_sock(con);
316 /* tipc_topsrv_queue_evt() - interrupt level call from a subscription instance
317 * The queued work is launched into tipc_conn_send_work()->tipc_conn_send_to_sock()
319 void tipc_topsrv_queue_evt(struct net *net, int conid,
320 u32 event, struct tipc_event *evt)
322 struct tipc_topsrv *srv = tipc_topsrv(net);
323 struct outqueue_entry *e;
324 struct tipc_conn *con;
326 con = tipc_conn_lookup(srv, conid);
333 e = kmalloc(sizeof(*e), GFP_ATOMIC);
336 e->inactive = (event == TIPC_SUBSCR_TIMEOUT);
337 memcpy(&e->evt, evt, sizeof(*evt));
338 spin_lock_bh(&con->outqueue_lock);
339 list_add_tail(&e->list, &con->outqueue);
340 spin_unlock_bh(&con->outqueue_lock);
342 if (queue_work(srv->send_wq, &con->swork))
348 /* tipc_conn_write_space - interrupt callback after a sendmsg EAGAIN
349 * Indicates that there now is more space in the send buffer
350 * The queued work is launched into tipc_send_work()->tipc_conn_send_to_sock()
352 static void tipc_conn_write_space(struct sock *sk)
354 struct tipc_conn *con;
356 read_lock_bh(&sk->sk_callback_lock);
357 con = sk->sk_user_data;
358 if (connected(con)) {
360 if (!queue_work(con->server->send_wq, &con->swork))
363 read_unlock_bh(&sk->sk_callback_lock);
366 static int tipc_conn_rcv_sub(struct tipc_topsrv *srv,
367 struct tipc_conn *con,
368 struct tipc_subscr *s)
370 struct tipc_net *tn = tipc_net(srv->net);
371 struct tipc_subscription *sub;
373 if (tipc_sub_read(s, filter) & TIPC_SUB_CANCEL) {
374 s->filter &= __constant_ntohl(~TIPC_SUB_CANCEL);
375 tipc_conn_delete_sub(con, s);
378 if (atomic_read(&tn->subscription_count) >= TIPC_MAX_SUBSCR) {
379 pr_warn("Subscription rejected, max (%u)\n", TIPC_MAX_SUBSCR);
382 sub = tipc_sub_subscribe(srv->net, s, con->conid);
385 atomic_inc(&tn->subscription_count);
386 spin_lock_bh(&con->sub_lock);
387 list_add(&sub->sub_list, &con->sub_list);
388 spin_unlock_bh(&con->sub_lock);
392 static int tipc_conn_rcv_from_sock(struct tipc_conn *con)
394 struct tipc_topsrv *srv = con->server;
395 struct sock *sk = con->sock->sk;
396 struct msghdr msg = {};
397 struct tipc_subscr s;
402 iov.iov_len = sizeof(s);
404 iov_iter_kvec(&msg.msg_iter, READ | ITER_KVEC, &iov, 1, iov.iov_len);
405 ret = sock_recvmsg(con->sock, &msg, MSG_DONTWAIT);
406 if (ret == -EWOULDBLOCK)
408 if (ret == sizeof(s)) {
409 read_lock_bh(&sk->sk_callback_lock);
410 /* RACE: the connection can be closed in the meantime */
411 if (likely(connected(con)))
412 ret = tipc_conn_rcv_sub(srv, con, &s);
413 read_unlock_bh(&sk->sk_callback_lock);
418 tipc_conn_close(con);
422 static void tipc_conn_recv_work(struct work_struct *work)
424 struct tipc_conn *con = container_of(work, struct tipc_conn, rwork);
427 while (connected(con)) {
428 if (tipc_conn_rcv_from_sock(con))
431 /* Don't flood Rx machine */
432 if (++count >= MAX_RECV_MSG_COUNT) {
440 /* tipc_conn_data_ready - interrupt callback indicating the socket has data
441 * The queued work is launched into tipc_recv_work()->tipc_conn_rcv_from_sock()
443 static void tipc_conn_data_ready(struct sock *sk)
445 struct tipc_conn *con;
447 read_lock_bh(&sk->sk_callback_lock);
448 con = sk->sk_user_data;
449 if (connected(con)) {
451 if (!queue_work(con->server->rcv_wq, &con->rwork))
454 read_unlock_bh(&sk->sk_callback_lock);
457 static void tipc_topsrv_accept(struct work_struct *work)
459 struct tipc_topsrv *srv = container_of(work, struct tipc_topsrv, awork);
460 struct socket *lsock = srv->listener;
461 struct socket *newsock;
462 struct tipc_conn *con;
467 ret = kernel_accept(lsock, &newsock, O_NONBLOCK);
470 con = tipc_conn_alloc(srv);
473 sock_release(newsock);
476 /* Register callbacks */
478 write_lock_bh(&newsk->sk_callback_lock);
479 newsk->sk_data_ready = tipc_conn_data_ready;
480 newsk->sk_write_space = tipc_conn_write_space;
481 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_toprsv_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 int imp = TIPC_CRITICAL_IMPORTANCE;
507 struct socket *lsock = NULL;
508 struct sockaddr_tipc saddr;
512 rc = sock_create_kern(srv->net, AF_TIPC, SOCK_SEQPACKET, 0, &lsock);
516 srv->listener = lsock;
518 write_lock_bh(&sk->sk_callback_lock);
519 sk->sk_data_ready = tipc_topsrv_listener_data_ready;
520 sk->sk_user_data = srv;
521 write_unlock_bh(&sk->sk_callback_lock);
523 rc = kernel_setsockopt(lsock, SOL_TIPC, TIPC_IMPORTANCE,
524 (char *)&imp, sizeof(imp));
528 saddr.family = AF_TIPC;
529 saddr.addrtype = TIPC_ADDR_NAMESEQ;
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 = kernel_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 *(u32 *)&sub.usr_handle = port;
580 con = tipc_conn_alloc(tipc_topsrv(net));
586 rc = tipc_conn_rcv_sub(tipc_topsrv(net), con, &sub);
593 void tipc_topsrv_kern_unsubscr(struct net *net, int conid)
595 struct tipc_conn *con;
597 con = tipc_conn_lookup(tipc_topsrv(net), conid);
601 test_and_clear_bit(CF_CONNECTED, &con->flags);
602 tipc_conn_delete_sub(con, NULL);
607 static void tipc_topsrv_kern_evt(struct net *net, struct tipc_event *evt)
609 u32 port = *(u32 *)&evt->s.usr_handle;
610 u32 self = tipc_own_addr(net);
611 struct sk_buff_head evtq;
614 skb = tipc_msg_create(TOP_SRV, 0, INT_H_SIZE, sizeof(*evt),
615 self, self, port, port, 0);
618 msg_set_dest_droppable(buf_msg(skb), true);
619 memcpy(msg_data(buf_msg(skb)), evt, sizeof(*evt));
620 skb_queue_head_init(&evtq);
621 __skb_queue_tail(&evtq, skb);
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 srv->max_rcvbuf_size = sizeof(struct tipc_subscr);
662 INIT_WORK(&srv->awork, tipc_topsrv_accept);
664 strscpy(srv->name, name, sizeof(srv->name));
666 atomic_set(&tn->subscription_count, 0);
668 spin_lock_init(&srv->idr_lock);
669 idr_init(&srv->conn_idr);
672 ret = tipc_topsrv_work_start(srv);
676 ret = tipc_topsrv_create_listener(srv);
683 tipc_topsrv_work_stop(srv);
689 static void tipc_topsrv_stop(struct net *net)
691 struct tipc_topsrv *srv = tipc_topsrv(net);
692 struct socket *lsock = srv->listener;
693 struct tipc_conn *con;
696 spin_lock_bh(&srv->idr_lock);
697 for (id = 0; srv->idr_in_use; id++) {
698 con = idr_find(&srv->conn_idr, id);
700 spin_unlock_bh(&srv->idr_lock);
701 tipc_conn_close(con);
702 spin_lock_bh(&srv->idr_lock);
705 __module_get(lsock->ops->owner);
706 __module_get(lsock->sk->sk_prot_creator->owner);
707 srv->listener = NULL;
708 spin_unlock_bh(&srv->idr_lock);
710 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);