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1/*
2 * net/tipc/server.c: TIPC server infrastructure
3 *
4 * Copyright (c) 2012-2013, Wind River Systems
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions are met:
9 *
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.
18 *
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.
22 *
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
27 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
28 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
29 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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.
34 */
35
36#include "server.h"
37#include "core.h"
38#include "socket.h"
39#include <net/sock.h>
40#include <linux/module.h>
41
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
46#define CF_SERVER 2
47
48#define sock2con(x) ((struct tipc_conn *)(x)->sk_user_data)
49
50/**
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
64 */
65struct tipc_conn {
66 struct kref kref;
67 int conid;
68 struct socket *sock;
69 unsigned long flags;
70 struct tipc_server *server;
71 struct work_struct rwork;
72 int (*rx_action) (struct tipc_conn *con);
73 void *usr_data;
74 struct list_head outqueue;
75 spinlock_t outqueue_lock;
76 struct work_struct swork;
77};
78
79/* An entry waiting to be sent */
80struct outqueue_entry {
81 struct list_head list;
82 struct kvec iov;
83 struct sockaddr_tipc dest;
84};
85
86static void tipc_recv_work(struct work_struct *work);
87static void tipc_send_work(struct work_struct *work);
88static void tipc_clean_outqueues(struct tipc_conn *con);
89
90static void tipc_conn_kref_release(struct kref *kref)
91{
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;
96 struct sock *sk;
97
98 if (sock) {
99 sk = sock->sk;
100 if (test_bit(CF_SERVER, &con->flags)) {
101 __module_get(sock->ops->owner);
102 __module_get(sk->sk_prot_creator->owner);
103 }
104 saddr->scope = -TIPC_NODE_SCOPE;
105 kernel_bind(sock, (struct sockaddr *)saddr, sizeof(*saddr));
106 sock_release(sock);
107 con->sock = NULL;
108
109 spin_lock_bh(&s->idr_lock);
110 idr_remove(&s->conn_idr, con->conid);
111 s->idr_in_use--;
112 spin_unlock_bh(&s->idr_lock);
113 }
114
115 tipc_clean_outqueues(con);
116 kfree(con);
117}
118
119static void conn_put(struct tipc_conn *con)
120{
121 kref_put(&con->kref, tipc_conn_kref_release);
122}
123
124static void conn_get(struct tipc_conn *con)
125{
126 kref_get(&con->kref);
127}
128
129static struct tipc_conn *tipc_conn_lookup(struct tipc_server *s, int conid)
130{
131 struct tipc_conn *con;
132
133 spin_lock_bh(&s->idr_lock);
134 con = idr_find(&s->conn_idr, conid);
135 if (con && test_bit(CF_CONNECTED, &con->flags))
136 conn_get(con);
137 else
138 con = NULL;
139 spin_unlock_bh(&s->idr_lock);
140 return con;
141}
142
143static void sock_data_ready(struct sock *sk)
144{
145 struct tipc_conn *con;
146
147 read_lock_bh(&sk->sk_callback_lock);
148 con = sock2con(sk);
149 if (con && test_bit(CF_CONNECTED, &con->flags)) {
150 conn_get(con);
151 if (!queue_work(con->server->rcv_wq, &con->rwork))
152 conn_put(con);
153 }
154 read_unlock_bh(&sk->sk_callback_lock);
155}
156
157static void sock_write_space(struct sock *sk)
158{
159 struct tipc_conn *con;
160
161 read_lock_bh(&sk->sk_callback_lock);
162 con = sock2con(sk);
163 if (con && test_bit(CF_CONNECTED, &con->flags)) {
164 conn_get(con);
165 if (!queue_work(con->server->send_wq, &con->swork))
166 conn_put(con);
167 }
168 read_unlock_bh(&sk->sk_callback_lock);
169}
170
171static void tipc_register_callbacks(struct socket *sock, struct tipc_conn *con)
172{
173 struct sock *sk = sock->sk;
174
175 write_lock_bh(&sk->sk_callback_lock);
176
177 sk->sk_data_ready = sock_data_ready;
178 sk->sk_write_space = sock_write_space;
179 sk->sk_user_data = con;
180
181 con->sock = sock;
182
183 write_unlock_bh(&sk->sk_callback_lock);
184}
185
186static void tipc_unregister_callbacks(struct tipc_conn *con)
187{
188 struct sock *sk = con->sock->sk;
189
190 write_lock_bh(&sk->sk_callback_lock);
191 sk->sk_user_data = NULL;
192 write_unlock_bh(&sk->sk_callback_lock);
193}
194
195static void tipc_close_conn(struct tipc_conn *con)
196{
197 struct tipc_server *s = con->server;
198
199 if (test_and_clear_bit(CF_CONNECTED, &con->flags)) {
200 tipc_unregister_callbacks(con);
201
202 if (con->conid)
203 s->tipc_conn_release(con->conid, con->usr_data);
204
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.
209 */
210 kernel_sock_shutdown(con->sock, SHUT_RDWR);
211
212 conn_put(con);
213 }
214}
215
216static struct tipc_conn *tipc_alloc_conn(struct tipc_server *s)
217{
218 struct tipc_conn *con;
219 int ret;
220
221 con = kzalloc(sizeof(struct tipc_conn), GFP_ATOMIC);
222 if (!con)
223 return ERR_PTR(-ENOMEM);
224
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);
230
231 spin_lock_bh(&s->idr_lock);
232 ret = idr_alloc(&s->conn_idr, con, 0, 0, GFP_ATOMIC);
233 if (ret < 0) {
234 kfree(con);
235 spin_unlock_bh(&s->idr_lock);
236 return ERR_PTR(-ENOMEM);
237 }
238 con->conid = ret;
239 s->idr_in_use++;
240 spin_unlock_bh(&s->idr_lock);
241
242 set_bit(CF_CONNECTED, &con->flags);
243 con->server = s;
244
245 return con;
246}
247
248static int tipc_receive_from_sock(struct tipc_conn *con)
249{
250 struct msghdr msg = {};
251 struct tipc_server *s = con->server;
252 struct sockaddr_tipc addr;
253 struct kvec iov;
254 void *buf;
255 int ret;
256
257 buf = kmem_cache_alloc(s->rcvbuf_cache, GFP_ATOMIC);
258 if (!buf) {
259 ret = -ENOMEM;
260 goto out_close;
261 }
262
263 iov.iov_base = buf;
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,
267 MSG_DONTWAIT);
268 if (ret <= 0) {
269 kmem_cache_free(s->rcvbuf_cache, buf);
270 goto out_close;
271 }
272
273 s->tipc_conn_recvmsg(sock_net(con->sock->sk), con->conid, &addr,
274 con->usr_data, buf, ret);
275
276 kmem_cache_free(s->rcvbuf_cache, buf);
277
278 return 0;
279
280out_close:
281 if (ret != -EWOULDBLOCK)
282 tipc_close_conn(con);
283 else if (ret == 0)
284 /* Don't return success if we really got EOF */
285 ret = -EAGAIN;
286
287 return ret;
288}
289
290static int tipc_accept_from_sock(struct tipc_conn *con)
291{
292 struct tipc_server *s = con->server;
293 struct socket *sock = con->sock;
294 struct socket *newsock;
295 struct tipc_conn *newcon;
296 int ret;
297
298 ret = kernel_accept(sock, &newsock, O_NONBLOCK);
299 if (ret < 0)
300 return ret;
301
302 newcon = tipc_alloc_conn(con->server);
303 if (IS_ERR(newcon)) {
304 ret = PTR_ERR(newcon);
305 sock_release(newsock);
306 return ret;
307 }
308
309 newcon->rx_action = tipc_receive_from_sock;
310 tipc_register_callbacks(newsock, newcon);
311
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);
316 return -ENOMEM;
317 }
318
319 /* Wake up receive process in case of 'SYN+' message */
320 newsock->sk->sk_data_ready(newsock->sk);
321 return ret;
322}
323
324static struct socket *tipc_create_listen_sock(struct tipc_conn *con)
325{
326 struct tipc_server *s = con->server;
327 struct socket *sock = NULL;
328 int ret;
329
330 ret = sock_create_kern(s->net, AF_TIPC, SOCK_SEQPACKET, 0, &sock);
331 if (ret < 0)
332 return NULL;
333 ret = kernel_setsockopt(sock, SOL_TIPC, TIPC_IMPORTANCE,
334 (char *)&s->imp, sizeof(s->imp));
335 if (ret < 0)
336 goto create_err;
337 ret = kernel_bind(sock, (struct sockaddr *)s->saddr, sizeof(*s->saddr));
338 if (ret < 0)
339 goto create_err;
340
341 switch (s->type) {
342 case SOCK_STREAM:
343 case SOCK_SEQPACKET:
344 con->rx_action = tipc_accept_from_sock;
345
346 ret = kernel_listen(sock, 0);
347 if (ret < 0)
348 goto create_err;
349 break;
350 case SOCK_DGRAM:
351 case SOCK_RDM:
352 con->rx_action = tipc_receive_from_sock;
353 break;
354 default:
355 pr_err("Unknown socket type %d\n", s->type);
356 goto create_err;
357 }
358
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.
364 *
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
372 * is closed.
373 */
374 module_put(sock->ops->owner);
375 module_put(sock->sk->sk_prot_creator->owner);
376 set_bit(CF_SERVER, &con->flags);
377
378 return sock;
379
380create_err:
381 kernel_sock_shutdown(sock, SHUT_RDWR);
382 sock_release(sock);
383 return NULL;
384}
385
386static int tipc_open_listening_sock(struct tipc_server *s)
387{
388 struct socket *sock;
389 struct tipc_conn *con;
390
391 con = tipc_alloc_conn(s);
392 if (IS_ERR(con))
393 return PTR_ERR(con);
394
395 sock = tipc_create_listen_sock(con);
396 if (!sock) {
397 idr_remove(&s->conn_idr, con->conid);
398 s->idr_in_use--;
399 kfree(con);
400 return -EINVAL;
401 }
402
403 tipc_register_callbacks(sock, con);
404 return 0;
405}
406
407static struct outqueue_entry *tipc_alloc_entry(void *data, int len)
408{
409 struct outqueue_entry *entry;
410 void *buf;
411
412 entry = kmalloc(sizeof(struct outqueue_entry), GFP_ATOMIC);
413 if (!entry)
414 return NULL;
415
416 buf = kmemdup(data, len, GFP_ATOMIC);
417 if (!buf) {
418 kfree(entry);
419 return NULL;
420 }
421
422 entry->iov.iov_base = buf;
423 entry->iov.iov_len = len;
424
425 return entry;
426}
427
428static void tipc_free_entry(struct outqueue_entry *e)
429{
430 kfree(e->iov.iov_base);
431 kfree(e);
432}
433
434static void tipc_clean_outqueues(struct tipc_conn *con)
435{
436 struct outqueue_entry *e, *safe;
437
438 spin_lock_bh(&con->outqueue_lock);
439 list_for_each_entry_safe(e, safe, &con->outqueue, list) {
440 list_del(&e->list);
441 tipc_free_entry(e);
442 }
443 spin_unlock_bh(&con->outqueue_lock);
444}
445
446int tipc_conn_sendmsg(struct tipc_server *s, int conid,
447 struct sockaddr_tipc *addr, void *data, size_t len)
448{
449 struct outqueue_entry *e;
450 struct tipc_conn *con;
451
452 con = tipc_conn_lookup(s, conid);
453 if (!con)
454 return -EINVAL;
455
456 if (!test_bit(CF_CONNECTED, &con->flags)) {
457 conn_put(con);
458 return 0;
459 }
460
461 e = tipc_alloc_entry(data, len);
462 if (!e) {
463 conn_put(con);
464 return -ENOMEM;
465 }
466
467 if (addr)
468 memcpy(&e->dest, addr, sizeof(struct sockaddr_tipc));
469
470 spin_lock_bh(&con->outqueue_lock);
471 list_add_tail(&e->list, &con->outqueue);
472 spin_unlock_bh(&con->outqueue_lock);
473
474 if (!queue_work(s->send_wq, &con->swork))
475 conn_put(con);
476 return 0;
477}
478
479void tipc_conn_terminate(struct tipc_server *s, int conid)
480{
481 struct tipc_conn *con;
482
483 con = tipc_conn_lookup(s, conid);
484 if (con) {
485 tipc_close_conn(con);
486 conn_put(con);
487 }
488}
489
490static void tipc_send_to_sock(struct tipc_conn *con)
491{
492 int count = 0;
493 struct tipc_server *s = con->server;
494 struct outqueue_entry *e;
495 struct msghdr msg;
496 int ret;
497
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,
501 list);
502 if ((struct list_head *) e == &con->outqueue)
503 break;
504 spin_unlock_bh(&con->outqueue_lock);
505
506 memset(&msg, 0, sizeof(msg));
507 msg.msg_flags = MSG_DONTWAIT;
508
509 if (s->type == SOCK_DGRAM || s->type == SOCK_RDM) {
510 msg.msg_name = &e->dest;
511 msg.msg_namelen = sizeof(struct sockaddr_tipc);
512 }
513 ret = kernel_sendmsg(con->sock, &msg, &e->iov, 1,
514 e->iov.iov_len);
515 if (ret == -EWOULDBLOCK || ret == 0) {
516 cond_resched();
517 goto out;
518 } else if (ret < 0) {
519 goto send_err;
520 }
521
522 /* Don't starve users filling buffers */
523 if (++count >= MAX_SEND_MSG_COUNT) {
524 cond_resched();
525 count = 0;
526 }
527
528 spin_lock_bh(&con->outqueue_lock);
529 list_del(&e->list);
530 tipc_free_entry(e);
531 }
532 spin_unlock_bh(&con->outqueue_lock);
533out:
534 return;
535
536send_err:
537 tipc_close_conn(con);
538}
539
540static void tipc_recv_work(struct work_struct *work)
541{
542 struct tipc_conn *con = container_of(work, struct tipc_conn, rwork);
543 int count = 0;
544
545 while (test_bit(CF_CONNECTED, &con->flags)) {
546 if (con->rx_action(con))
547 break;
548
549 /* Don't flood Rx machine */
550 if (++count >= MAX_RECV_MSG_COUNT) {
551 cond_resched();
552 count = 0;
553 }
554 }
555 conn_put(con);
556}
557
558static void tipc_send_work(struct work_struct *work)
559{
560 struct tipc_conn *con = container_of(work, struct tipc_conn, swork);
561
562 if (test_bit(CF_CONNECTED, &con->flags))
563 tipc_send_to_sock(con);
564
565 conn_put(con);
566}
567
568static void tipc_work_stop(struct tipc_server *s)
569{
570 destroy_workqueue(s->rcv_wq);
571 destroy_workqueue(s->send_wq);
572}
573
574static int tipc_work_start(struct tipc_server *s)
575{
576 s->rcv_wq = alloc_ordered_workqueue("tipc_rcv", 0);
577 if (!s->rcv_wq) {
578 pr_err("can't start tipc receive workqueue\n");
579 return -ENOMEM;
580 }
581
582 s->send_wq = alloc_ordered_workqueue("tipc_send", 0);
583 if (!s->send_wq) {
584 pr_err("can't start tipc send workqueue\n");
585 destroy_workqueue(s->rcv_wq);
586 return -ENOMEM;
587 }
588
589 return 0;
590}
591
592int tipc_server_start(struct tipc_server *s)
593{
594 int ret;
595
596 spin_lock_init(&s->idr_lock);
597 idr_init(&s->conn_idr);
598 s->idr_in_use = 0;
599
600 s->rcvbuf_cache = kmem_cache_create(s->name, s->max_rcvbuf_size,
601 0, SLAB_HWCACHE_ALIGN, NULL);
602 if (!s->rcvbuf_cache)
603 return -ENOMEM;
604
605 ret = tipc_work_start(s);
606 if (ret < 0) {
607 kmem_cache_destroy(s->rcvbuf_cache);
608 return ret;
609 }
610 ret = tipc_open_listening_sock(s);
611 if (ret < 0) {
612 tipc_work_stop(s);
613 kmem_cache_destroy(s->rcvbuf_cache);
614 return ret;
615 }
616 return ret;
617}
618
619void tipc_server_stop(struct tipc_server *s)
620{
621 struct tipc_conn *con;
622 int id;
623
624 spin_lock_bh(&s->idr_lock);
625 for (id = 0; s->idr_in_use; id++) {
626 con = idr_find(&s->conn_idr, id);
627 if (con) {
628 spin_unlock_bh(&s->idr_lock);
629 tipc_close_conn(con);
630 spin_lock_bh(&s->idr_lock);
631 }
632 }
633 spin_unlock_bh(&s->idr_lock);
634
635 tipc_work_stop(s);
636 kmem_cache_destroy(s->rcvbuf_cache);
637 idr_destroy(&s->conn_idr);
638}