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new helper: memcpy_from_msg()
[deliverable/linux.git] / net / caif / caif_socket.c
1 /*
2 * Copyright (C) ST-Ericsson AB 2010
3 * Author: Sjur Brendeland
4 * License terms: GNU General Public License (GPL) version 2
5 */
6
7 #define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
8
9 #include <linux/fs.h>
10 #include <linux/init.h>
11 #include <linux/module.h>
12 #include <linux/sched.h>
13 #include <linux/spinlock.h>
14 #include <linux/mutex.h>
15 #include <linux/list.h>
16 #include <linux/wait.h>
17 #include <linux/poll.h>
18 #include <linux/tcp.h>
19 #include <linux/uaccess.h>
20 #include <linux/debugfs.h>
21 #include <linux/caif/caif_socket.h>
22 #include <linux/pkt_sched.h>
23 #include <net/sock.h>
24 #include <net/tcp_states.h>
25 #include <net/caif/caif_layer.h>
26 #include <net/caif/caif_dev.h>
27 #include <net/caif/cfpkt.h>
28
29 MODULE_LICENSE("GPL");
30 MODULE_ALIAS_NETPROTO(AF_CAIF);
31
32 /*
33 * CAIF state is re-using the TCP socket states.
34 * caif_states stored in sk_state reflect the state as reported by
35 * the CAIF stack, while sk_socket->state is the state of the socket.
36 */
37 enum caif_states {
38 CAIF_CONNECTED = TCP_ESTABLISHED,
39 CAIF_CONNECTING = TCP_SYN_SENT,
40 CAIF_DISCONNECTED = TCP_CLOSE
41 };
42
43 #define TX_FLOW_ON_BIT 1
44 #define RX_FLOW_ON_BIT 2
45
46 struct caifsock {
47 struct sock sk; /* must be first member */
48 struct cflayer layer;
49 u32 flow_state;
50 struct caif_connect_request conn_req;
51 struct mutex readlock;
52 struct dentry *debugfs_socket_dir;
53 int headroom, tailroom, maxframe;
54 };
55
56 static int rx_flow_is_on(struct caifsock *cf_sk)
57 {
58 return test_bit(RX_FLOW_ON_BIT,
59 (void *) &cf_sk->flow_state);
60 }
61
62 static int tx_flow_is_on(struct caifsock *cf_sk)
63 {
64 return test_bit(TX_FLOW_ON_BIT,
65 (void *) &cf_sk->flow_state);
66 }
67
68 static void set_rx_flow_off(struct caifsock *cf_sk)
69 {
70 clear_bit(RX_FLOW_ON_BIT,
71 (void *) &cf_sk->flow_state);
72 }
73
74 static void set_rx_flow_on(struct caifsock *cf_sk)
75 {
76 set_bit(RX_FLOW_ON_BIT,
77 (void *) &cf_sk->flow_state);
78 }
79
80 static void set_tx_flow_off(struct caifsock *cf_sk)
81 {
82 clear_bit(TX_FLOW_ON_BIT,
83 (void *) &cf_sk->flow_state);
84 }
85
86 static void set_tx_flow_on(struct caifsock *cf_sk)
87 {
88 set_bit(TX_FLOW_ON_BIT,
89 (void *) &cf_sk->flow_state);
90 }
91
92 static void caif_read_lock(struct sock *sk)
93 {
94 struct caifsock *cf_sk;
95 cf_sk = container_of(sk, struct caifsock, sk);
96 mutex_lock(&cf_sk->readlock);
97 }
98
99 static void caif_read_unlock(struct sock *sk)
100 {
101 struct caifsock *cf_sk;
102 cf_sk = container_of(sk, struct caifsock, sk);
103 mutex_unlock(&cf_sk->readlock);
104 }
105
106 static int sk_rcvbuf_lowwater(struct caifsock *cf_sk)
107 {
108 /* A quarter of full buffer is used a low water mark */
109 return cf_sk->sk.sk_rcvbuf / 4;
110 }
111
112 static void caif_flow_ctrl(struct sock *sk, int mode)
113 {
114 struct caifsock *cf_sk;
115 cf_sk = container_of(sk, struct caifsock, sk);
116 if (cf_sk->layer.dn && cf_sk->layer.dn->modemcmd)
117 cf_sk->layer.dn->modemcmd(cf_sk->layer.dn, mode);
118 }
119
120 /*
121 * Copied from sock.c:sock_queue_rcv_skb(), but changed so packets are
122 * not dropped, but CAIF is sending flow off instead.
123 */
124 static int caif_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
125 {
126 int err;
127 unsigned long flags;
128 struct sk_buff_head *list = &sk->sk_receive_queue;
129 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
130
131 if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
132 (unsigned int)sk->sk_rcvbuf && rx_flow_is_on(cf_sk)) {
133 net_dbg_ratelimited("sending flow OFF (queue len = %d %d)\n",
134 atomic_read(&cf_sk->sk.sk_rmem_alloc),
135 sk_rcvbuf_lowwater(cf_sk));
136 set_rx_flow_off(cf_sk);
137 caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ);
138 }
139
140 err = sk_filter(sk, skb);
141 if (err)
142 return err;
143 if (!sk_rmem_schedule(sk, skb, skb->truesize) && rx_flow_is_on(cf_sk)) {
144 set_rx_flow_off(cf_sk);
145 net_dbg_ratelimited("sending flow OFF due to rmem_schedule\n");
146 caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ);
147 }
148 skb->dev = NULL;
149 skb_set_owner_r(skb, sk);
150 /* Cache the SKB length before we tack it onto the receive
151 * queue. Once it is added it no longer belongs to us and
152 * may be freed by other threads of control pulling packets
153 * from the queue.
154 */
155 spin_lock_irqsave(&list->lock, flags);
156 if (!sock_flag(sk, SOCK_DEAD))
157 __skb_queue_tail(list, skb);
158 spin_unlock_irqrestore(&list->lock, flags);
159
160 if (!sock_flag(sk, SOCK_DEAD))
161 sk->sk_data_ready(sk);
162 else
163 kfree_skb(skb);
164 return 0;
165 }
166
167 /* Packet Receive Callback function called from CAIF Stack */
168 static int caif_sktrecv_cb(struct cflayer *layr, struct cfpkt *pkt)
169 {
170 struct caifsock *cf_sk;
171 struct sk_buff *skb;
172
173 cf_sk = container_of(layr, struct caifsock, layer);
174 skb = cfpkt_tonative(pkt);
175
176 if (unlikely(cf_sk->sk.sk_state != CAIF_CONNECTED)) {
177 kfree_skb(skb);
178 return 0;
179 }
180 caif_queue_rcv_skb(&cf_sk->sk, skb);
181 return 0;
182 }
183
184 static void cfsk_hold(struct cflayer *layr)
185 {
186 struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
187 sock_hold(&cf_sk->sk);
188 }
189
190 static void cfsk_put(struct cflayer *layr)
191 {
192 struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
193 sock_put(&cf_sk->sk);
194 }
195
196 /* Packet Control Callback function called from CAIF */
197 static void caif_ctrl_cb(struct cflayer *layr,
198 enum caif_ctrlcmd flow,
199 int phyid)
200 {
201 struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
202 switch (flow) {
203 case CAIF_CTRLCMD_FLOW_ON_IND:
204 /* OK from modem to start sending again */
205 set_tx_flow_on(cf_sk);
206 cf_sk->sk.sk_state_change(&cf_sk->sk);
207 break;
208
209 case CAIF_CTRLCMD_FLOW_OFF_IND:
210 /* Modem asks us to shut up */
211 set_tx_flow_off(cf_sk);
212 cf_sk->sk.sk_state_change(&cf_sk->sk);
213 break;
214
215 case CAIF_CTRLCMD_INIT_RSP:
216 /* We're now connected */
217 caif_client_register_refcnt(&cf_sk->layer,
218 cfsk_hold, cfsk_put);
219 cf_sk->sk.sk_state = CAIF_CONNECTED;
220 set_tx_flow_on(cf_sk);
221 cf_sk->sk.sk_shutdown = 0;
222 cf_sk->sk.sk_state_change(&cf_sk->sk);
223 break;
224
225 case CAIF_CTRLCMD_DEINIT_RSP:
226 /* We're now disconnected */
227 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
228 cf_sk->sk.sk_state_change(&cf_sk->sk);
229 break;
230
231 case CAIF_CTRLCMD_INIT_FAIL_RSP:
232 /* Connect request failed */
233 cf_sk->sk.sk_err = ECONNREFUSED;
234 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
235 cf_sk->sk.sk_shutdown = SHUTDOWN_MASK;
236 /*
237 * Socket "standards" seems to require POLLOUT to
238 * be set at connect failure.
239 */
240 set_tx_flow_on(cf_sk);
241 cf_sk->sk.sk_state_change(&cf_sk->sk);
242 break;
243
244 case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
245 /* Modem has closed this connection, or device is down. */
246 cf_sk->sk.sk_shutdown = SHUTDOWN_MASK;
247 cf_sk->sk.sk_err = ECONNRESET;
248 set_rx_flow_on(cf_sk);
249 cf_sk->sk.sk_error_report(&cf_sk->sk);
250 break;
251
252 default:
253 pr_debug("Unexpected flow command %d\n", flow);
254 }
255 }
256
257 static void caif_check_flow_release(struct sock *sk)
258 {
259 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
260
261 if (rx_flow_is_on(cf_sk))
262 return;
263
264 if (atomic_read(&sk->sk_rmem_alloc) <= sk_rcvbuf_lowwater(cf_sk)) {
265 set_rx_flow_on(cf_sk);
266 caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_ON_REQ);
267 }
268 }
269
270 /*
271 * Copied from unix_dgram_recvmsg, but removed credit checks,
272 * changed locking, address handling and added MSG_TRUNC.
273 */
274 static int caif_seqpkt_recvmsg(struct kiocb *iocb, struct socket *sock,
275 struct msghdr *m, size_t len, int flags)
276
277 {
278 struct sock *sk = sock->sk;
279 struct sk_buff *skb;
280 int ret;
281 int copylen;
282
283 ret = -EOPNOTSUPP;
284 if (m->msg_flags&MSG_OOB)
285 goto read_error;
286
287 skb = skb_recv_datagram(sk, flags, 0 , &ret);
288 if (!skb)
289 goto read_error;
290 copylen = skb->len;
291 if (len < copylen) {
292 m->msg_flags |= MSG_TRUNC;
293 copylen = len;
294 }
295
296 ret = skb_copy_datagram_msg(skb, 0, m, copylen);
297 if (ret)
298 goto out_free;
299
300 ret = (flags & MSG_TRUNC) ? skb->len : copylen;
301 out_free:
302 skb_free_datagram(sk, skb);
303 caif_check_flow_release(sk);
304 return ret;
305
306 read_error:
307 return ret;
308 }
309
310
311 /* Copied from unix_stream_wait_data, identical except for lock call. */
312 static long caif_stream_data_wait(struct sock *sk, long timeo)
313 {
314 DEFINE_WAIT(wait);
315 lock_sock(sk);
316
317 for (;;) {
318 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
319
320 if (!skb_queue_empty(&sk->sk_receive_queue) ||
321 sk->sk_err ||
322 sk->sk_state != CAIF_CONNECTED ||
323 sock_flag(sk, SOCK_DEAD) ||
324 (sk->sk_shutdown & RCV_SHUTDOWN) ||
325 signal_pending(current) ||
326 !timeo)
327 break;
328
329 set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
330 release_sock(sk);
331 timeo = schedule_timeout(timeo);
332 lock_sock(sk);
333 clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
334 }
335
336 finish_wait(sk_sleep(sk), &wait);
337 release_sock(sk);
338 return timeo;
339 }
340
341
342 /*
343 * Copied from unix_stream_recvmsg, but removed credit checks,
344 * changed locking calls, changed address handling.
345 */
346 static int caif_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
347 struct msghdr *msg, size_t size,
348 int flags)
349 {
350 struct sock *sk = sock->sk;
351 int copied = 0;
352 int target;
353 int err = 0;
354 long timeo;
355
356 err = -EOPNOTSUPP;
357 if (flags&MSG_OOB)
358 goto out;
359
360 /*
361 * Lock the socket to prevent queue disordering
362 * while sleeps in memcpy_tomsg
363 */
364 err = -EAGAIN;
365 if (sk->sk_state == CAIF_CONNECTING)
366 goto out;
367
368 caif_read_lock(sk);
369 target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
370 timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT);
371
372 do {
373 int chunk;
374 struct sk_buff *skb;
375
376 lock_sock(sk);
377 skb = skb_dequeue(&sk->sk_receive_queue);
378 caif_check_flow_release(sk);
379
380 if (skb == NULL) {
381 if (copied >= target)
382 goto unlock;
383 /*
384 * POSIX 1003.1g mandates this order.
385 */
386 err = sock_error(sk);
387 if (err)
388 goto unlock;
389 err = -ECONNRESET;
390 if (sk->sk_shutdown & RCV_SHUTDOWN)
391 goto unlock;
392
393 err = -EPIPE;
394 if (sk->sk_state != CAIF_CONNECTED)
395 goto unlock;
396 if (sock_flag(sk, SOCK_DEAD))
397 goto unlock;
398
399 release_sock(sk);
400
401 err = -EAGAIN;
402 if (!timeo)
403 break;
404
405 caif_read_unlock(sk);
406
407 timeo = caif_stream_data_wait(sk, timeo);
408
409 if (signal_pending(current)) {
410 err = sock_intr_errno(timeo);
411 goto out;
412 }
413 caif_read_lock(sk);
414 continue;
415 unlock:
416 release_sock(sk);
417 break;
418 }
419 release_sock(sk);
420 chunk = min_t(unsigned int, skb->len, size);
421 if (memcpy_toiovec(msg->msg_iov, skb->data, chunk)) {
422 skb_queue_head(&sk->sk_receive_queue, skb);
423 if (copied == 0)
424 copied = -EFAULT;
425 break;
426 }
427 copied += chunk;
428 size -= chunk;
429
430 /* Mark read part of skb as used */
431 if (!(flags & MSG_PEEK)) {
432 skb_pull(skb, chunk);
433
434 /* put the skb back if we didn't use it up. */
435 if (skb->len) {
436 skb_queue_head(&sk->sk_receive_queue, skb);
437 break;
438 }
439 kfree_skb(skb);
440
441 } else {
442 /*
443 * It is questionable, see note in unix_dgram_recvmsg.
444 */
445 /* put message back and return */
446 skb_queue_head(&sk->sk_receive_queue, skb);
447 break;
448 }
449 } while (size);
450 caif_read_unlock(sk);
451
452 out:
453 return copied ? : err;
454 }
455
456 /*
457 * Copied from sock.c:sock_wait_for_wmem, but change to wait for
458 * CAIF flow-on and sock_writable.
459 */
460 static long caif_wait_for_flow_on(struct caifsock *cf_sk,
461 int wait_writeable, long timeo, int *err)
462 {
463 struct sock *sk = &cf_sk->sk;
464 DEFINE_WAIT(wait);
465 for (;;) {
466 *err = 0;
467 if (tx_flow_is_on(cf_sk) &&
468 (!wait_writeable || sock_writeable(&cf_sk->sk)))
469 break;
470 *err = -ETIMEDOUT;
471 if (!timeo)
472 break;
473 *err = -ERESTARTSYS;
474 if (signal_pending(current))
475 break;
476 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
477 *err = -ECONNRESET;
478 if (sk->sk_shutdown & SHUTDOWN_MASK)
479 break;
480 *err = -sk->sk_err;
481 if (sk->sk_err)
482 break;
483 *err = -EPIPE;
484 if (cf_sk->sk.sk_state != CAIF_CONNECTED)
485 break;
486 timeo = schedule_timeout(timeo);
487 }
488 finish_wait(sk_sleep(sk), &wait);
489 return timeo;
490 }
491
492 /*
493 * Transmit a SKB. The device may temporarily request re-transmission
494 * by returning EAGAIN.
495 */
496 static int transmit_skb(struct sk_buff *skb, struct caifsock *cf_sk,
497 int noblock, long timeo)
498 {
499 struct cfpkt *pkt;
500
501 pkt = cfpkt_fromnative(CAIF_DIR_OUT, skb);
502 memset(skb->cb, 0, sizeof(struct caif_payload_info));
503 cfpkt_set_prio(pkt, cf_sk->sk.sk_priority);
504
505 if (cf_sk->layer.dn == NULL) {
506 kfree_skb(skb);
507 return -EINVAL;
508 }
509
510 return cf_sk->layer.dn->transmit(cf_sk->layer.dn, pkt);
511 }
512
513 /* Copied from af_unix:unix_dgram_sendmsg, and adapted to CAIF */
514 static int caif_seqpkt_sendmsg(struct kiocb *kiocb, struct socket *sock,
515 struct msghdr *msg, size_t len)
516 {
517 struct sock *sk = sock->sk;
518 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
519 int buffer_size;
520 int ret = 0;
521 struct sk_buff *skb = NULL;
522 int noblock;
523 long timeo;
524 caif_assert(cf_sk);
525 ret = sock_error(sk);
526 if (ret)
527 goto err;
528
529 ret = -EOPNOTSUPP;
530 if (msg->msg_flags&MSG_OOB)
531 goto err;
532
533 ret = -EOPNOTSUPP;
534 if (msg->msg_namelen)
535 goto err;
536
537 ret = -EINVAL;
538 if (unlikely(msg->msg_iov->iov_base == NULL))
539 goto err;
540 noblock = msg->msg_flags & MSG_DONTWAIT;
541
542 timeo = sock_sndtimeo(sk, noblock);
543 timeo = caif_wait_for_flow_on(container_of(sk, struct caifsock, sk),
544 1, timeo, &ret);
545
546 if (ret)
547 goto err;
548 ret = -EPIPE;
549 if (cf_sk->sk.sk_state != CAIF_CONNECTED ||
550 sock_flag(sk, SOCK_DEAD) ||
551 (sk->sk_shutdown & RCV_SHUTDOWN))
552 goto err;
553
554 /* Error if trying to write more than maximum frame size. */
555 ret = -EMSGSIZE;
556 if (len > cf_sk->maxframe && cf_sk->sk.sk_protocol != CAIFPROTO_RFM)
557 goto err;
558
559 buffer_size = len + cf_sk->headroom + cf_sk->tailroom;
560
561 ret = -ENOMEM;
562 skb = sock_alloc_send_skb(sk, buffer_size, noblock, &ret);
563
564 if (!skb || skb_tailroom(skb) < buffer_size)
565 goto err;
566
567 skb_reserve(skb, cf_sk->headroom);
568
569 ret = memcpy_from_msg(skb_put(skb, len), msg, len);
570
571 if (ret)
572 goto err;
573 ret = transmit_skb(skb, cf_sk, noblock, timeo);
574 if (ret < 0)
575 /* skb is already freed */
576 return ret;
577
578 return len;
579 err:
580 kfree_skb(skb);
581 return ret;
582 }
583
584 /*
585 * Copied from unix_stream_sendmsg and adapted to CAIF:
586 * Changed removed permission handling and added waiting for flow on
587 * and other minor adaptations.
588 */
589 static int caif_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
590 struct msghdr *msg, size_t len)
591 {
592 struct sock *sk = sock->sk;
593 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
594 int err, size;
595 struct sk_buff *skb;
596 int sent = 0;
597 long timeo;
598
599 err = -EOPNOTSUPP;
600 if (unlikely(msg->msg_flags&MSG_OOB))
601 goto out_err;
602
603 if (unlikely(msg->msg_namelen))
604 goto out_err;
605
606 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
607 timeo = caif_wait_for_flow_on(cf_sk, 1, timeo, &err);
608
609 if (unlikely(sk->sk_shutdown & SEND_SHUTDOWN))
610 goto pipe_err;
611
612 while (sent < len) {
613
614 size = len-sent;
615
616 if (size > cf_sk->maxframe)
617 size = cf_sk->maxframe;
618
619 /* If size is more than half of sndbuf, chop up message */
620 if (size > ((sk->sk_sndbuf >> 1) - 64))
621 size = (sk->sk_sndbuf >> 1) - 64;
622
623 if (size > SKB_MAX_ALLOC)
624 size = SKB_MAX_ALLOC;
625
626 skb = sock_alloc_send_skb(sk,
627 size + cf_sk->headroom +
628 cf_sk->tailroom,
629 msg->msg_flags&MSG_DONTWAIT,
630 &err);
631 if (skb == NULL)
632 goto out_err;
633
634 skb_reserve(skb, cf_sk->headroom);
635 /*
636 * If you pass two values to the sock_alloc_send_skb
637 * it tries to grab the large buffer with GFP_NOFS
638 * (which can fail easily), and if it fails grab the
639 * fallback size buffer which is under a page and will
640 * succeed. [Alan]
641 */
642 size = min_t(int, size, skb_tailroom(skb));
643
644 err = memcpy_from_msg(skb_put(skb, size), msg, size);
645 if (err) {
646 kfree_skb(skb);
647 goto out_err;
648 }
649 err = transmit_skb(skb, cf_sk,
650 msg->msg_flags&MSG_DONTWAIT, timeo);
651 if (err < 0)
652 /* skb is already freed */
653 goto pipe_err;
654
655 sent += size;
656 }
657
658 return sent;
659
660 pipe_err:
661 if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
662 send_sig(SIGPIPE, current, 0);
663 err = -EPIPE;
664 out_err:
665 return sent ? : err;
666 }
667
668 static int setsockopt(struct socket *sock,
669 int lvl, int opt, char __user *ov, unsigned int ol)
670 {
671 struct sock *sk = sock->sk;
672 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
673 int linksel;
674
675 if (cf_sk->sk.sk_socket->state != SS_UNCONNECTED)
676 return -ENOPROTOOPT;
677
678 switch (opt) {
679 case CAIFSO_LINK_SELECT:
680 if (ol < sizeof(int))
681 return -EINVAL;
682 if (lvl != SOL_CAIF)
683 goto bad_sol;
684 if (copy_from_user(&linksel, ov, sizeof(int)))
685 return -EINVAL;
686 lock_sock(&(cf_sk->sk));
687 cf_sk->conn_req.link_selector = linksel;
688 release_sock(&cf_sk->sk);
689 return 0;
690
691 case CAIFSO_REQ_PARAM:
692 if (lvl != SOL_CAIF)
693 goto bad_sol;
694 if (cf_sk->sk.sk_protocol != CAIFPROTO_UTIL)
695 return -ENOPROTOOPT;
696 lock_sock(&(cf_sk->sk));
697 if (ol > sizeof(cf_sk->conn_req.param.data) ||
698 copy_from_user(&cf_sk->conn_req.param.data, ov, ol)) {
699 release_sock(&cf_sk->sk);
700 return -EINVAL;
701 }
702 cf_sk->conn_req.param.size = ol;
703 release_sock(&cf_sk->sk);
704 return 0;
705
706 default:
707 return -ENOPROTOOPT;
708 }
709
710 return 0;
711 bad_sol:
712 return -ENOPROTOOPT;
713
714 }
715
716 /*
717 * caif_connect() - Connect a CAIF Socket
718 * Copied and modified af_irda.c:irda_connect().
719 *
720 * Note : by consulting "errno", the user space caller may learn the cause
721 * of the failure. Most of them are visible in the function, others may come
722 * from subroutines called and are listed here :
723 * o -EAFNOSUPPORT: bad socket family or type.
724 * o -ESOCKTNOSUPPORT: bad socket type or protocol
725 * o -EINVAL: bad socket address, or CAIF link type
726 * o -ECONNREFUSED: remote end refused the connection.
727 * o -EINPROGRESS: connect request sent but timed out (or non-blocking)
728 * o -EISCONN: already connected.
729 * o -ETIMEDOUT: Connection timed out (send timeout)
730 * o -ENODEV: No link layer to send request
731 * o -ECONNRESET: Received Shutdown indication or lost link layer
732 * o -ENOMEM: Out of memory
733 *
734 * State Strategy:
735 * o sk_state: holds the CAIF_* protocol state, it's updated by
736 * caif_ctrl_cb.
737 * o sock->state: holds the SS_* socket state and is updated by connect and
738 * disconnect.
739 */
740 static int caif_connect(struct socket *sock, struct sockaddr *uaddr,
741 int addr_len, int flags)
742 {
743 struct sock *sk = sock->sk;
744 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
745 long timeo;
746 int err;
747 int ifindex, headroom, tailroom;
748 unsigned int mtu;
749 struct net_device *dev;
750
751 lock_sock(sk);
752
753 err = -EAFNOSUPPORT;
754 if (uaddr->sa_family != AF_CAIF)
755 goto out;
756
757 switch (sock->state) {
758 case SS_UNCONNECTED:
759 /* Normal case, a fresh connect */
760 caif_assert(sk->sk_state == CAIF_DISCONNECTED);
761 break;
762 case SS_CONNECTING:
763 switch (sk->sk_state) {
764 case CAIF_CONNECTED:
765 sock->state = SS_CONNECTED;
766 err = -EISCONN;
767 goto out;
768 case CAIF_DISCONNECTED:
769 /* Reconnect allowed */
770 break;
771 case CAIF_CONNECTING:
772 err = -EALREADY;
773 if (flags & O_NONBLOCK)
774 goto out;
775 goto wait_connect;
776 }
777 break;
778 case SS_CONNECTED:
779 caif_assert(sk->sk_state == CAIF_CONNECTED ||
780 sk->sk_state == CAIF_DISCONNECTED);
781 if (sk->sk_shutdown & SHUTDOWN_MASK) {
782 /* Allow re-connect after SHUTDOWN_IND */
783 caif_disconnect_client(sock_net(sk), &cf_sk->layer);
784 caif_free_client(&cf_sk->layer);
785 break;
786 }
787 /* No reconnect on a seqpacket socket */
788 err = -EISCONN;
789 goto out;
790 case SS_DISCONNECTING:
791 case SS_FREE:
792 caif_assert(1); /*Should never happen */
793 break;
794 }
795 sk->sk_state = CAIF_DISCONNECTED;
796 sock->state = SS_UNCONNECTED;
797 sk_stream_kill_queues(&cf_sk->sk);
798
799 err = -EINVAL;
800 if (addr_len != sizeof(struct sockaddr_caif))
801 goto out;
802
803 memcpy(&cf_sk->conn_req.sockaddr, uaddr,
804 sizeof(struct sockaddr_caif));
805
806 /* Move to connecting socket, start sending Connect Requests */
807 sock->state = SS_CONNECTING;
808 sk->sk_state = CAIF_CONNECTING;
809
810 /* Check priority value comming from socket */
811 /* if priority value is out of range it will be ajusted */
812 if (cf_sk->sk.sk_priority > CAIF_PRIO_MAX)
813 cf_sk->conn_req.priority = CAIF_PRIO_MAX;
814 else if (cf_sk->sk.sk_priority < CAIF_PRIO_MIN)
815 cf_sk->conn_req.priority = CAIF_PRIO_MIN;
816 else
817 cf_sk->conn_req.priority = cf_sk->sk.sk_priority;
818
819 /*ifindex = id of the interface.*/
820 cf_sk->conn_req.ifindex = cf_sk->sk.sk_bound_dev_if;
821
822 cf_sk->layer.receive = caif_sktrecv_cb;
823
824 err = caif_connect_client(sock_net(sk), &cf_sk->conn_req,
825 &cf_sk->layer, &ifindex, &headroom, &tailroom);
826
827 if (err < 0) {
828 cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
829 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
830 goto out;
831 }
832
833 err = -ENODEV;
834 rcu_read_lock();
835 dev = dev_get_by_index_rcu(sock_net(sk), ifindex);
836 if (!dev) {
837 rcu_read_unlock();
838 goto out;
839 }
840 cf_sk->headroom = LL_RESERVED_SPACE_EXTRA(dev, headroom);
841 mtu = dev->mtu;
842 rcu_read_unlock();
843
844 cf_sk->tailroom = tailroom;
845 cf_sk->maxframe = mtu - (headroom + tailroom);
846 if (cf_sk->maxframe < 1) {
847 pr_warn("CAIF Interface MTU too small (%d)\n", dev->mtu);
848 err = -ENODEV;
849 goto out;
850 }
851
852 err = -EINPROGRESS;
853 wait_connect:
854
855 if (sk->sk_state != CAIF_CONNECTED && (flags & O_NONBLOCK))
856 goto out;
857
858 timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
859
860 release_sock(sk);
861 err = -ERESTARTSYS;
862 timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
863 sk->sk_state != CAIF_CONNECTING,
864 timeo);
865 lock_sock(sk);
866 if (timeo < 0)
867 goto out; /* -ERESTARTSYS */
868
869 err = -ETIMEDOUT;
870 if (timeo == 0 && sk->sk_state != CAIF_CONNECTED)
871 goto out;
872 if (sk->sk_state != CAIF_CONNECTED) {
873 sock->state = SS_UNCONNECTED;
874 err = sock_error(sk);
875 if (!err)
876 err = -ECONNREFUSED;
877 goto out;
878 }
879 sock->state = SS_CONNECTED;
880 err = 0;
881 out:
882 release_sock(sk);
883 return err;
884 }
885
886 /*
887 * caif_release() - Disconnect a CAIF Socket
888 * Copied and modified af_irda.c:irda_release().
889 */
890 static int caif_release(struct socket *sock)
891 {
892 struct sock *sk = sock->sk;
893 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
894
895 if (!sk)
896 return 0;
897
898 set_tx_flow_off(cf_sk);
899
900 /*
901 * Ensure that packets are not queued after this point in time.
902 * caif_queue_rcv_skb checks SOCK_DEAD holding the queue lock,
903 * this ensures no packets when sock is dead.
904 */
905 spin_lock_bh(&sk->sk_receive_queue.lock);
906 sock_set_flag(sk, SOCK_DEAD);
907 spin_unlock_bh(&sk->sk_receive_queue.lock);
908 sock->sk = NULL;
909
910 WARN_ON(IS_ERR(cf_sk->debugfs_socket_dir));
911 debugfs_remove_recursive(cf_sk->debugfs_socket_dir);
912
913 lock_sock(&(cf_sk->sk));
914 sk->sk_state = CAIF_DISCONNECTED;
915 sk->sk_shutdown = SHUTDOWN_MASK;
916
917 caif_disconnect_client(sock_net(sk), &cf_sk->layer);
918 cf_sk->sk.sk_socket->state = SS_DISCONNECTING;
919 wake_up_interruptible_poll(sk_sleep(sk), POLLERR|POLLHUP);
920
921 sock_orphan(sk);
922 sk_stream_kill_queues(&cf_sk->sk);
923 release_sock(sk);
924 sock_put(sk);
925 return 0;
926 }
927
928 /* Copied from af_unix.c:unix_poll(), added CAIF tx_flow handling */
929 static unsigned int caif_poll(struct file *file,
930 struct socket *sock, poll_table *wait)
931 {
932 struct sock *sk = sock->sk;
933 unsigned int mask;
934 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
935
936 sock_poll_wait(file, sk_sleep(sk), wait);
937 mask = 0;
938
939 /* exceptional events? */
940 if (sk->sk_err)
941 mask |= POLLERR;
942 if (sk->sk_shutdown == SHUTDOWN_MASK)
943 mask |= POLLHUP;
944 if (sk->sk_shutdown & RCV_SHUTDOWN)
945 mask |= POLLRDHUP;
946
947 /* readable? */
948 if (!skb_queue_empty(&sk->sk_receive_queue) ||
949 (sk->sk_shutdown & RCV_SHUTDOWN))
950 mask |= POLLIN | POLLRDNORM;
951
952 /*
953 * we set writable also when the other side has shut down the
954 * connection. This prevents stuck sockets.
955 */
956 if (sock_writeable(sk) && tx_flow_is_on(cf_sk))
957 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
958
959 return mask;
960 }
961
962 static const struct proto_ops caif_seqpacket_ops = {
963 .family = PF_CAIF,
964 .owner = THIS_MODULE,
965 .release = caif_release,
966 .bind = sock_no_bind,
967 .connect = caif_connect,
968 .socketpair = sock_no_socketpair,
969 .accept = sock_no_accept,
970 .getname = sock_no_getname,
971 .poll = caif_poll,
972 .ioctl = sock_no_ioctl,
973 .listen = sock_no_listen,
974 .shutdown = sock_no_shutdown,
975 .setsockopt = setsockopt,
976 .getsockopt = sock_no_getsockopt,
977 .sendmsg = caif_seqpkt_sendmsg,
978 .recvmsg = caif_seqpkt_recvmsg,
979 .mmap = sock_no_mmap,
980 .sendpage = sock_no_sendpage,
981 };
982
983 static const struct proto_ops caif_stream_ops = {
984 .family = PF_CAIF,
985 .owner = THIS_MODULE,
986 .release = caif_release,
987 .bind = sock_no_bind,
988 .connect = caif_connect,
989 .socketpair = sock_no_socketpair,
990 .accept = sock_no_accept,
991 .getname = sock_no_getname,
992 .poll = caif_poll,
993 .ioctl = sock_no_ioctl,
994 .listen = sock_no_listen,
995 .shutdown = sock_no_shutdown,
996 .setsockopt = setsockopt,
997 .getsockopt = sock_no_getsockopt,
998 .sendmsg = caif_stream_sendmsg,
999 .recvmsg = caif_stream_recvmsg,
1000 .mmap = sock_no_mmap,
1001 .sendpage = sock_no_sendpage,
1002 };
1003
1004 /* This function is called when a socket is finally destroyed. */
1005 static void caif_sock_destructor(struct sock *sk)
1006 {
1007 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
1008 caif_assert(!atomic_read(&sk->sk_wmem_alloc));
1009 caif_assert(sk_unhashed(sk));
1010 caif_assert(!sk->sk_socket);
1011 if (!sock_flag(sk, SOCK_DEAD)) {
1012 pr_debug("Attempt to release alive CAIF socket: %p\n", sk);
1013 return;
1014 }
1015 sk_stream_kill_queues(&cf_sk->sk);
1016 caif_free_client(&cf_sk->layer);
1017 }
1018
1019 static int caif_create(struct net *net, struct socket *sock, int protocol,
1020 int kern)
1021 {
1022 struct sock *sk = NULL;
1023 struct caifsock *cf_sk = NULL;
1024 static struct proto prot = {.name = "PF_CAIF",
1025 .owner = THIS_MODULE,
1026 .obj_size = sizeof(struct caifsock),
1027 };
1028
1029 if (!capable(CAP_SYS_ADMIN) && !capable(CAP_NET_ADMIN))
1030 return -EPERM;
1031 /*
1032 * The sock->type specifies the socket type to use.
1033 * The CAIF socket is a packet stream in the sense
1034 * that it is packet based. CAIF trusts the reliability
1035 * of the link, no resending is implemented.
1036 */
1037 if (sock->type == SOCK_SEQPACKET)
1038 sock->ops = &caif_seqpacket_ops;
1039 else if (sock->type == SOCK_STREAM)
1040 sock->ops = &caif_stream_ops;
1041 else
1042 return -ESOCKTNOSUPPORT;
1043
1044 if (protocol < 0 || protocol >= CAIFPROTO_MAX)
1045 return -EPROTONOSUPPORT;
1046 /*
1047 * Set the socket state to unconnected. The socket state
1048 * is really not used at all in the net/core or socket.c but the
1049 * initialization makes sure that sock->state is not uninitialized.
1050 */
1051 sk = sk_alloc(net, PF_CAIF, GFP_KERNEL, &prot);
1052 if (!sk)
1053 return -ENOMEM;
1054
1055 cf_sk = container_of(sk, struct caifsock, sk);
1056
1057 /* Store the protocol */
1058 sk->sk_protocol = (unsigned char) protocol;
1059
1060 /* Initialize default priority for well-known cases */
1061 switch (protocol) {
1062 case CAIFPROTO_AT:
1063 sk->sk_priority = TC_PRIO_CONTROL;
1064 break;
1065 case CAIFPROTO_RFM:
1066 sk->sk_priority = TC_PRIO_INTERACTIVE_BULK;
1067 break;
1068 default:
1069 sk->sk_priority = TC_PRIO_BESTEFFORT;
1070 }
1071
1072 /*
1073 * Lock in order to try to stop someone from opening the socket
1074 * too early.
1075 */
1076 lock_sock(&(cf_sk->sk));
1077
1078 /* Initialize the nozero default sock structure data. */
1079 sock_init_data(sock, sk);
1080 sk->sk_destruct = caif_sock_destructor;
1081
1082 mutex_init(&cf_sk->readlock); /* single task reading lock */
1083 cf_sk->layer.ctrlcmd = caif_ctrl_cb;
1084 cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
1085 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
1086
1087 set_tx_flow_off(cf_sk);
1088 set_rx_flow_on(cf_sk);
1089
1090 /* Set default options on configuration */
1091 cf_sk->conn_req.link_selector = CAIF_LINK_LOW_LATENCY;
1092 cf_sk->conn_req.protocol = protocol;
1093 release_sock(&cf_sk->sk);
1094 return 0;
1095 }
1096
1097
1098 static struct net_proto_family caif_family_ops = {
1099 .family = PF_CAIF,
1100 .create = caif_create,
1101 .owner = THIS_MODULE,
1102 };
1103
1104 static int __init caif_sktinit_module(void)
1105 {
1106 int err = sock_register(&caif_family_ops);
1107 if (!err)
1108 return err;
1109 return 0;
1110 }
1111
1112 static void __exit caif_sktexit_module(void)
1113 {
1114 sock_unregister(PF_CAIF);
1115 }
1116 module_init(caif_sktinit_module);
1117 module_exit(caif_sktexit_module);
Linux kernel - Deliverables
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