2 * net/tipc/server.c: TIPC server infrastructure
4 * Copyright (c) 2012-2013, Wind River Systems
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the names of the copyright holders nor the names of its
16 * contributors may be used to endorse or promote products derived from
17 * this software without specific prior written permission.
19 * Alternatively, this software may be distributed under the terms of the
20 * GNU General Public License ("GPL") version 2 as published by the Free
21 * Software Foundation.
23 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
24 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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30 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
31 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
32 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
33 * POSSIBILITY OF SUCH DAMAGE.
40 #include <linux/module.h>
42 /* Number of messages to send before rescheduling */
43 #define MAX_SEND_MSG_COUNT 25
44 #define MAX_RECV_MSG_COUNT 25
45 #define CF_CONNECTED 1
48 #define sock2con(x) ((struct tipc_conn *)(x)->sk_user_data)
51 * struct tipc_conn - TIPC connection structure
52 * @kref: reference counter to connection object
53 * @conid: connection identifier
54 * @sock: socket handler associated with connection
55 * @flags: indicates connection state
56 * @server: pointer to connected server
57 * @rwork: receive work item
58 * @usr_data: user-specified field
59 * @rx_action: what to do when connection socket is active
60 * @outqueue: pointer to first outbound message in queue
61 * @outqueue_lock: control access to the outqueue
62 * @outqueue: list of connection objects for its server
63 * @swork: send work item
70 struct tipc_server *server;
71 struct work_struct rwork;
72 int (*rx_action) (struct tipc_conn *con);
74 struct list_head outqueue;
75 spinlock_t outqueue_lock;
76 struct work_struct swork;
79 /* An entry waiting to be sent */
80 struct outqueue_entry {
81 struct list_head list;
83 struct sockaddr_tipc dest;
86 static void tipc_recv_work(struct work_struct *work);
87 static void tipc_send_work(struct work_struct *work);
88 static void tipc_clean_outqueues(struct tipc_conn *con);
90 static void tipc_conn_kref_release(struct kref *kref)
92 struct tipc_conn *con = container_of(kref, struct tipc_conn, kref);
93 struct tipc_server *s = con->server;
94 struct sockaddr_tipc *saddr = s->saddr;
95 struct socket *sock = con->sock;
100 if (test_bit(CF_SERVER, &con->flags)) {
101 __module_get(sock->ops->owner);
102 __module_get(sk->sk_prot_creator->owner);
104 saddr->scope = -TIPC_NODE_SCOPE;
105 kernel_bind(sock, (struct sockaddr *)saddr, sizeof(*saddr));
109 spin_lock_bh(&s->idr_lock);
110 idr_remove(&s->conn_idr, con->conid);
112 spin_unlock_bh(&s->idr_lock);
115 tipc_clean_outqueues(con);
119 static void conn_put(struct tipc_conn *con)
121 kref_put(&con->kref, tipc_conn_kref_release);
124 static void conn_get(struct tipc_conn *con)
126 kref_get(&con->kref);
129 static struct tipc_conn *tipc_conn_lookup(struct tipc_server *s, int conid)
131 struct tipc_conn *con;
133 spin_lock_bh(&s->idr_lock);
134 con = idr_find(&s->conn_idr, conid);
135 if (con && test_bit(CF_CONNECTED, &con->flags))
139 spin_unlock_bh(&s->idr_lock);
143 static void sock_data_ready(struct sock *sk)
145 struct tipc_conn *con;
147 read_lock_bh(&sk->sk_callback_lock);
149 if (con && test_bit(CF_CONNECTED, &con->flags)) {
151 if (!queue_work(con->server->rcv_wq, &con->rwork))
154 read_unlock_bh(&sk->sk_callback_lock);
157 static void sock_write_space(struct sock *sk)
159 struct tipc_conn *con;
161 read_lock_bh(&sk->sk_callback_lock);
163 if (con && test_bit(CF_CONNECTED, &con->flags)) {
165 if (!queue_work(con->server->send_wq, &con->swork))
168 read_unlock_bh(&sk->sk_callback_lock);
171 static void tipc_register_callbacks(struct socket *sock, struct tipc_conn *con)
173 struct sock *sk = sock->sk;
175 write_lock_bh(&sk->sk_callback_lock);
177 sk->sk_data_ready = sock_data_ready;
178 sk->sk_write_space = sock_write_space;
179 sk->sk_user_data = con;
183 write_unlock_bh(&sk->sk_callback_lock);
186 static void tipc_unregister_callbacks(struct tipc_conn *con)
188 struct sock *sk = con->sock->sk;
190 write_lock_bh(&sk->sk_callback_lock);
191 sk->sk_user_data = NULL;
192 write_unlock_bh(&sk->sk_callback_lock);
195 static void tipc_close_conn(struct tipc_conn *con)
197 struct tipc_server *s = con->server;
199 if (test_and_clear_bit(CF_CONNECTED, &con->flags)) {
200 tipc_unregister_callbacks(con);
203 s->tipc_conn_release(con->conid, con->usr_data);
205 /* We shouldn't flush pending works as we may be in the
206 * thread. In fact the races with pending rx/tx work structs
207 * are harmless for us here as we have already deleted this
208 * connection from server connection list.
210 kernel_sock_shutdown(con->sock, SHUT_RDWR);
216 static struct tipc_conn *tipc_alloc_conn(struct tipc_server *s)
218 struct tipc_conn *con;
221 con = kzalloc(sizeof(struct tipc_conn), GFP_ATOMIC);
223 return ERR_PTR(-ENOMEM);
225 kref_init(&con->kref);
226 INIT_LIST_HEAD(&con->outqueue);
227 spin_lock_init(&con->outqueue_lock);
228 INIT_WORK(&con->swork, tipc_send_work);
229 INIT_WORK(&con->rwork, tipc_recv_work);
231 spin_lock_bh(&s->idr_lock);
232 ret = idr_alloc(&s->conn_idr, con, 0, 0, GFP_ATOMIC);
235 spin_unlock_bh(&s->idr_lock);
236 return ERR_PTR(-ENOMEM);
240 spin_unlock_bh(&s->idr_lock);
242 set_bit(CF_CONNECTED, &con->flags);
248 static int tipc_receive_from_sock(struct tipc_conn *con)
250 struct msghdr msg = {};
251 struct tipc_server *s = con->server;
252 struct sockaddr_tipc addr;
257 buf = kmem_cache_alloc(s->rcvbuf_cache, GFP_ATOMIC);
264 iov.iov_len = s->max_rcvbuf_size;
265 msg.msg_name = &addr;
266 ret = kernel_recvmsg(con->sock, &msg, &iov, 1, iov.iov_len,
269 kmem_cache_free(s->rcvbuf_cache, buf);
273 s->tipc_conn_recvmsg(sock_net(con->sock->sk), con->conid, &addr,
274 con->usr_data, buf, ret);
276 kmem_cache_free(s->rcvbuf_cache, buf);
281 if (ret != -EWOULDBLOCK)
282 tipc_close_conn(con);
284 /* Don't return success if we really got EOF */
290 static int tipc_accept_from_sock(struct tipc_conn *con)
292 struct tipc_server *s = con->server;
293 struct socket *sock = con->sock;
294 struct socket *newsock;
295 struct tipc_conn *newcon;
298 ret = kernel_accept(sock, &newsock, O_NONBLOCK);
302 newcon = tipc_alloc_conn(con->server);
303 if (IS_ERR(newcon)) {
304 ret = PTR_ERR(newcon);
305 sock_release(newsock);
309 newcon->rx_action = tipc_receive_from_sock;
310 tipc_register_callbacks(newsock, newcon);
312 /* Notify that new connection is incoming */
313 newcon->usr_data = s->tipc_conn_new(newcon->conid);
314 if (!newcon->usr_data) {
315 sock_release(newsock);
319 /* Wake up receive process in case of 'SYN+' message */
320 newsock->sk->sk_data_ready(newsock->sk);
324 static struct socket *tipc_create_listen_sock(struct tipc_conn *con)
326 struct tipc_server *s = con->server;
327 struct socket *sock = NULL;
330 ret = sock_create_kern(s->net, AF_TIPC, SOCK_SEQPACKET, 0, &sock);
333 ret = kernel_setsockopt(sock, SOL_TIPC, TIPC_IMPORTANCE,
334 (char *)&s->imp, sizeof(s->imp));
337 ret = kernel_bind(sock, (struct sockaddr *)s->saddr, sizeof(*s->saddr));
344 con->rx_action = tipc_accept_from_sock;
346 ret = kernel_listen(sock, 0);
352 con->rx_action = tipc_receive_from_sock;
355 pr_err("Unknown socket type %d\n", s->type);
359 /* As server's listening socket owner and creator is the same module,
360 * we have to decrease TIPC module reference count to guarantee that
361 * it remains zero after the server socket is created, otherwise,
362 * executing "rmmod" command is unable to make TIPC module deleted
363 * after TIPC module is inserted successfully.
365 * However, the reference count is ever increased twice in
366 * sock_create_kern(): one is to increase the reference count of owner
367 * of TIPC socket's proto_ops struct; another is to increment the
368 * reference count of owner of TIPC proto struct. Therefore, we must
369 * decrement the module reference count twice to ensure that it keeps
370 * zero after server's listening socket is created. Of course, we
371 * must bump the module reference count twice as well before the socket
374 module_put(sock->ops->owner);
375 module_put(sock->sk->sk_prot_creator->owner);
376 set_bit(CF_SERVER, &con->flags);
381 kernel_sock_shutdown(sock, SHUT_RDWR);
386 static int tipc_open_listening_sock(struct tipc_server *s)
389 struct tipc_conn *con;
391 con = tipc_alloc_conn(s);
395 sock = tipc_create_listen_sock(con);
397 idr_remove(&s->conn_idr, con->conid);
403 tipc_register_callbacks(sock, con);
407 static struct outqueue_entry *tipc_alloc_entry(void *data, int len)
409 struct outqueue_entry *entry;
412 entry = kmalloc(sizeof(struct outqueue_entry), GFP_ATOMIC);
416 buf = kmemdup(data, len, GFP_ATOMIC);
422 entry->iov.iov_base = buf;
423 entry->iov.iov_len = len;
428 static void tipc_free_entry(struct outqueue_entry *e)
430 kfree(e->iov.iov_base);
434 static void tipc_clean_outqueues(struct tipc_conn *con)
436 struct outqueue_entry *e, *safe;
438 spin_lock_bh(&con->outqueue_lock);
439 list_for_each_entry_safe(e, safe, &con->outqueue, list) {
443 spin_unlock_bh(&con->outqueue_lock);
446 int tipc_conn_sendmsg(struct tipc_server *s, int conid,
447 struct sockaddr_tipc *addr, void *data, size_t len)
449 struct outqueue_entry *e;
450 struct tipc_conn *con;
452 con = tipc_conn_lookup(s, conid);
456 if (!test_bit(CF_CONNECTED, &con->flags)) {
461 e = tipc_alloc_entry(data, len);
468 memcpy(&e->dest, addr, sizeof(struct sockaddr_tipc));
470 spin_lock_bh(&con->outqueue_lock);
471 list_add_tail(&e->list, &con->outqueue);
472 spin_unlock_bh(&con->outqueue_lock);
474 if (!queue_work(s->send_wq, &con->swork))
479 void tipc_conn_terminate(struct tipc_server *s, int conid)
481 struct tipc_conn *con;
483 con = tipc_conn_lookup(s, conid);
485 tipc_close_conn(con);
490 static void tipc_send_to_sock(struct tipc_conn *con)
493 struct tipc_server *s = con->server;
494 struct outqueue_entry *e;
498 spin_lock_bh(&con->outqueue_lock);
499 while (test_bit(CF_CONNECTED, &con->flags)) {
500 e = list_entry(con->outqueue.next, struct outqueue_entry,
502 if ((struct list_head *) e == &con->outqueue)
504 spin_unlock_bh(&con->outqueue_lock);
506 memset(&msg, 0, sizeof(msg));
507 msg.msg_flags = MSG_DONTWAIT;
509 if (s->type == SOCK_DGRAM || s->type == SOCK_RDM) {
510 msg.msg_name = &e->dest;
511 msg.msg_namelen = sizeof(struct sockaddr_tipc);
513 ret = kernel_sendmsg(con->sock, &msg, &e->iov, 1,
515 if (ret == -EWOULDBLOCK || ret == 0) {
518 } else if (ret < 0) {
522 /* Don't starve users filling buffers */
523 if (++count >= MAX_SEND_MSG_COUNT) {
528 spin_lock_bh(&con->outqueue_lock);
532 spin_unlock_bh(&con->outqueue_lock);
537 tipc_close_conn(con);
540 static void tipc_recv_work(struct work_struct *work)
542 struct tipc_conn *con = container_of(work, struct tipc_conn, rwork);
545 while (test_bit(CF_CONNECTED, &con->flags)) {
546 if (con->rx_action(con))
549 /* Don't flood Rx machine */
550 if (++count >= MAX_RECV_MSG_COUNT) {
558 static void tipc_send_work(struct work_struct *work)
560 struct tipc_conn *con = container_of(work, struct tipc_conn, swork);
562 if (test_bit(CF_CONNECTED, &con->flags))
563 tipc_send_to_sock(con);
568 static void tipc_work_stop(struct tipc_server *s)
570 destroy_workqueue(s->rcv_wq);
571 destroy_workqueue(s->send_wq);
574 static int tipc_work_start(struct tipc_server *s)
576 s->rcv_wq = alloc_ordered_workqueue("tipc_rcv", 0);
578 pr_err("can't start tipc receive workqueue\n");
582 s->send_wq = alloc_ordered_workqueue("tipc_send", 0);
584 pr_err("can't start tipc send workqueue\n");
585 destroy_workqueue(s->rcv_wq);
592 int tipc_server_start(struct tipc_server *s)
596 spin_lock_init(&s->idr_lock);
597 idr_init(&s->conn_idr);
600 s->rcvbuf_cache = kmem_cache_create(s->name, s->max_rcvbuf_size,
601 0, SLAB_HWCACHE_ALIGN, NULL);
602 if (!s->rcvbuf_cache)
605 ret = tipc_work_start(s);
607 kmem_cache_destroy(s->rcvbuf_cache);
610 ret = tipc_open_listening_sock(s);
613 kmem_cache_destroy(s->rcvbuf_cache);
619 void tipc_server_stop(struct tipc_server *s)
621 struct tipc_conn *con;
624 spin_lock_bh(&s->idr_lock);
625 for (id = 0; s->idr_in_use; id++) {
626 con = idr_find(&s->conn_idr, id);
628 spin_unlock_bh(&s->idr_lock);
629 tipc_close_conn(con);
630 spin_lock_bh(&s->idr_lock);
633 spin_unlock_bh(&s->idr_lock);
636 kmem_cache_destroy(s->rcvbuf_cache);
637 idr_destroy(&s->conn_idr);