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Linux 5.1-rc1
[linux/fpc-iii.git] / net / caif / caif_socket.c
blob416717c57cd1f6e851dd24cf7777ce0c470253cb
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/signal.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 void 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 bool queued = false;
131
132 if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
133 (unsigned int)sk->sk_rcvbuf && rx_flow_is_on(cf_sk)) {
134 net_dbg_ratelimited("sending flow OFF (queue len = %d %d)\n",
135 atomic_read(&cf_sk->sk.sk_rmem_alloc),
136 sk_rcvbuf_lowwater(cf_sk));
137 set_rx_flow_off(cf_sk);
138 caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ);
139 }
140
141 err = sk_filter(sk, skb);
142 if (err)
143 goto out;
144
145 if (!sk_rmem_schedule(sk, skb, skb->truesize) && rx_flow_is_on(cf_sk)) {
146 set_rx_flow_off(cf_sk);
147 net_dbg_ratelimited("sending flow OFF due to rmem_schedule\n");
148 caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ);
149 }
150 skb->dev = NULL;
151 skb_set_owner_r(skb, sk);
152 spin_lock_irqsave(&list->lock, flags);
153 queued = !sock_flag(sk, SOCK_DEAD);
154 if (queued)
155 __skb_queue_tail(list, skb);
156 spin_unlock_irqrestore(&list->lock, flags);
157 out:
158 if (queued)
159 sk->sk_data_ready(sk);
160 else
161 kfree_skb(skb);
162 }
163
164 /* Packet Receive Callback function called from CAIF Stack */
165 static int caif_sktrecv_cb(struct cflayer *layr, struct cfpkt *pkt)
166 {
167 struct caifsock *cf_sk;
168 struct sk_buff *skb;
169
170 cf_sk = container_of(layr, struct caifsock, layer);
171 skb = cfpkt_tonative(pkt);
172
173 if (unlikely(cf_sk->sk.sk_state != CAIF_CONNECTED)) {
174 kfree_skb(skb);
175 return 0;
176 }
177 caif_queue_rcv_skb(&cf_sk->sk, skb);
178 return 0;
179 }
180
181 static void cfsk_hold(struct cflayer *layr)
182 {
183 struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
184 sock_hold(&cf_sk->sk);
185 }
186
187 static void cfsk_put(struct cflayer *layr)
188 {
189 struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
190 sock_put(&cf_sk->sk);
191 }
192
193 /* Packet Control Callback function called from CAIF */
194 static void caif_ctrl_cb(struct cflayer *layr,
195 enum caif_ctrlcmd flow,
196 int phyid)
197 {
198 struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
199 switch (flow) {
200 case CAIF_CTRLCMD_FLOW_ON_IND:
201 /* OK from modem to start sending again */
202 set_tx_flow_on(cf_sk);
203 cf_sk->sk.sk_state_change(&cf_sk->sk);
204 break;
205
206 case CAIF_CTRLCMD_FLOW_OFF_IND:
207 /* Modem asks us to shut up */
208 set_tx_flow_off(cf_sk);
209 cf_sk->sk.sk_state_change(&cf_sk->sk);
210 break;
211
212 case CAIF_CTRLCMD_INIT_RSP:
213 /* We're now connected */
214 caif_client_register_refcnt(&cf_sk->layer,
215 cfsk_hold, cfsk_put);
216 cf_sk->sk.sk_state = CAIF_CONNECTED;
217 set_tx_flow_on(cf_sk);
218 cf_sk->sk.sk_shutdown = 0;
219 cf_sk->sk.sk_state_change(&cf_sk->sk);
220 break;
221
222 case CAIF_CTRLCMD_DEINIT_RSP:
223 /* We're now disconnected */
224 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
225 cf_sk->sk.sk_state_change(&cf_sk->sk);
226 break;
227
228 case CAIF_CTRLCMD_INIT_FAIL_RSP:
229 /* Connect request failed */
230 cf_sk->sk.sk_err = ECONNREFUSED;
231 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
232 cf_sk->sk.sk_shutdown = SHUTDOWN_MASK;
233 /*
234 * Socket "standards" seems to require POLLOUT to
235 * be set at connect failure.
236 */
237 set_tx_flow_on(cf_sk);
238 cf_sk->sk.sk_state_change(&cf_sk->sk);
239 break;
240
241 case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
242 /* Modem has closed this connection, or device is down. */
243 cf_sk->sk.sk_shutdown = SHUTDOWN_MASK;
244 cf_sk->sk.sk_err = ECONNRESET;
245 set_rx_flow_on(cf_sk);
246 cf_sk->sk.sk_error_report(&cf_sk->sk);
247 break;
248
249 default:
250 pr_debug("Unexpected flow command %d\n", flow);
251 }
252 }
253
254 static void caif_check_flow_release(struct sock *sk)
255 {
256 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
257
258 if (rx_flow_is_on(cf_sk))
259 return;
260
261 if (atomic_read(&sk->sk_rmem_alloc) <= sk_rcvbuf_lowwater(cf_sk)) {
262 set_rx_flow_on(cf_sk);
263 caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_ON_REQ);
264 }
265 }
266
267 /*
268 * Copied from unix_dgram_recvmsg, but removed credit checks,
269 * changed locking, address handling and added MSG_TRUNC.
270 */
271 static int caif_seqpkt_recvmsg(struct socket *sock, struct msghdr *m,
272 size_t len, int flags)
273
274 {
275 struct sock *sk = sock->sk;
276 struct sk_buff *skb;
277 int ret;
278 int copylen;
279
280 ret = -EOPNOTSUPP;
281 if (flags & MSG_OOB)
282 goto read_error;
283
284 skb = skb_recv_datagram(sk, flags, 0 , &ret);
285 if (!skb)
286 goto read_error;
287 copylen = skb->len;
288 if (len < copylen) {
289 m->msg_flags |= MSG_TRUNC;
290 copylen = len;
291 }
292
293 ret = skb_copy_datagram_msg(skb, 0, m, copylen);
294 if (ret)
295 goto out_free;
296
297 ret = (flags & MSG_TRUNC) ? skb->len : copylen;
298 out_free:
299 skb_free_datagram(sk, skb);
300 caif_check_flow_release(sk);
301 return ret;
302
303 read_error:
304 return ret;
305 }
306
307
308 /* Copied from unix_stream_wait_data, identical except for lock call. */
309 static long caif_stream_data_wait(struct sock *sk, long timeo)
310 {
311 DEFINE_WAIT(wait);
312 lock_sock(sk);
313
314 for (;;) {
315 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
316
317 if (!skb_queue_empty(&sk->sk_receive_queue) ||
318 sk->sk_err ||
319 sk->sk_state != CAIF_CONNECTED ||
320 sock_flag(sk, SOCK_DEAD) ||
321 (sk->sk_shutdown & RCV_SHUTDOWN) ||
322 signal_pending(current) ||
323 !timeo)
324 break;
325
326 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
327 release_sock(sk);
328 timeo = schedule_timeout(timeo);
329 lock_sock(sk);
330
331 if (sock_flag(sk, SOCK_DEAD))
332 break;
333
334 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
335 }
336
337 finish_wait(sk_sleep(sk), &wait);
338 release_sock(sk);
339 return timeo;
340 }
341
342
343 /*
344 * Copied from unix_stream_recvmsg, but removed credit checks,
345 * changed locking calls, changed address handling.
346 */
347 static int caif_stream_recvmsg(struct socket *sock, struct msghdr *msg,
348 size_t size, 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 if (sock_flag(sk, SOCK_DEAD)) {
378 err = -ECONNRESET;
379 goto unlock;
380 }
381 skb = skb_dequeue(&sk->sk_receive_queue);
382 caif_check_flow_release(sk);
383
384 if (skb == NULL) {
385 if (copied >= target)
386 goto unlock;
387 /*
388 * POSIX 1003.1g mandates this order.
389 */
390 err = sock_error(sk);
391 if (err)
392 goto unlock;
393 err = -ECONNRESET;
394 if (sk->sk_shutdown & RCV_SHUTDOWN)
395 goto unlock;
396
397 err = -EPIPE;
398 if (sk->sk_state != CAIF_CONNECTED)
399 goto unlock;
400 if (sock_flag(sk, SOCK_DEAD))
401 goto unlock;
402
403 release_sock(sk);
404
405 err = -EAGAIN;
406 if (!timeo)
407 break;
408
409 caif_read_unlock(sk);
410
411 timeo = caif_stream_data_wait(sk, timeo);
412
413 if (signal_pending(current)) {
414 err = sock_intr_errno(timeo);
415 goto out;
416 }
417 caif_read_lock(sk);
418 continue;
419 unlock:
420 release_sock(sk);
421 break;
422 }
423 release_sock(sk);
424 chunk = min_t(unsigned int, skb->len, size);
425 if (memcpy_to_msg(msg, skb->data, chunk)) {
426 skb_queue_head(&sk->sk_receive_queue, skb);
427 if (copied == 0)
428 copied = -EFAULT;
429 break;
430 }
431 copied += chunk;
432 size -= chunk;
433
434 /* Mark read part of skb as used */
435 if (!(flags & MSG_PEEK)) {
436 skb_pull(skb, chunk);
437
438 /* put the skb back if we didn't use it up. */
439 if (skb->len) {
440 skb_queue_head(&sk->sk_receive_queue, skb);
441 break;
442 }
443 kfree_skb(skb);
444
445 } else {
446 /*
447 * It is questionable, see note in unix_dgram_recvmsg.
448 */
449 /* put message back and return */
450 skb_queue_head(&sk->sk_receive_queue, skb);
451 break;
452 }
453 } while (size);
454 caif_read_unlock(sk);
455
456 out:
457 return copied ? : err;
458 }
459
460 /*
461 * Copied from sock.c:sock_wait_for_wmem, but change to wait for
462 * CAIF flow-on and sock_writable.
463 */
464 static long caif_wait_for_flow_on(struct caifsock *cf_sk,
465 int wait_writeable, long timeo, int *err)
466 {
467 struct sock *sk = &cf_sk->sk;
468 DEFINE_WAIT(wait);
469 for (;;) {
470 *err = 0;
471 if (tx_flow_is_on(cf_sk) &&
472 (!wait_writeable || sock_writeable(&cf_sk->sk)))
473 break;
474 *err = -ETIMEDOUT;
475 if (!timeo)
476 break;
477 *err = -ERESTARTSYS;
478 if (signal_pending(current))
479 break;
480 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
481 *err = -ECONNRESET;
482 if (sk->sk_shutdown & SHUTDOWN_MASK)
483 break;
484 *err = -sk->sk_err;
485 if (sk->sk_err)
486 break;
487 *err = -EPIPE;
488 if (cf_sk->sk.sk_state != CAIF_CONNECTED)
489 break;
490 timeo = schedule_timeout(timeo);
491 }
492 finish_wait(sk_sleep(sk), &wait);
493 return timeo;
494 }
495
496 /*
497 * Transmit a SKB. The device may temporarily request re-transmission
498 * by returning EAGAIN.
499 */
500 static int transmit_skb(struct sk_buff *skb, struct caifsock *cf_sk,
501 int noblock, long timeo)
502 {
503 struct cfpkt *pkt;
504
505 pkt = cfpkt_fromnative(CAIF_DIR_OUT, skb);
506 memset(skb->cb, 0, sizeof(struct caif_payload_info));
507 cfpkt_set_prio(pkt, cf_sk->sk.sk_priority);
508
509 if (cf_sk->layer.dn == NULL) {
510 kfree_skb(skb);
511 return -EINVAL;
512 }
513
514 return cf_sk->layer.dn->transmit(cf_sk->layer.dn, pkt);
515 }
516
517 /* Copied from af_unix:unix_dgram_sendmsg, and adapted to CAIF */
518 static int caif_seqpkt_sendmsg(struct socket *sock, struct msghdr *msg,
519 size_t len)
520 {
521 struct sock *sk = sock->sk;
522 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
523 int buffer_size;
524 int ret = 0;
525 struct sk_buff *skb = NULL;
526 int noblock;
527 long timeo;
528 caif_assert(cf_sk);
529 ret = sock_error(sk);
530 if (ret)
531 goto err;
532
533 ret = -EOPNOTSUPP;
534 if (msg->msg_flags&MSG_OOB)
535 goto err;
536
537 ret = -EOPNOTSUPP;
538 if (msg->msg_namelen)
539 goto err;
540
541 ret = -EINVAL;
542 if (unlikely(msg->msg_iter.iov->iov_base == NULL))
543 goto err;
544 noblock = msg->msg_flags & MSG_DONTWAIT;
545
546 timeo = sock_sndtimeo(sk, noblock);
547 timeo = caif_wait_for_flow_on(container_of(sk, struct caifsock, sk),
548 1, timeo, &ret);
549
550 if (ret)
551 goto err;
552 ret = -EPIPE;
553 if (cf_sk->sk.sk_state != CAIF_CONNECTED ||
554 sock_flag(sk, SOCK_DEAD) ||
555 (sk->sk_shutdown & RCV_SHUTDOWN))
556 goto err;
557
558 /* Error if trying to write more than maximum frame size. */
559 ret = -EMSGSIZE;
560 if (len > cf_sk->maxframe && cf_sk->sk.sk_protocol != CAIFPROTO_RFM)
561 goto err;
562
563 buffer_size = len + cf_sk->headroom + cf_sk->tailroom;
564
565 ret = -ENOMEM;
566 skb = sock_alloc_send_skb(sk, buffer_size, noblock, &ret);
567
568 if (!skb || skb_tailroom(skb) < buffer_size)
569 goto err;
570
571 skb_reserve(skb, cf_sk->headroom);
572
573 ret = memcpy_from_msg(skb_put(skb, len), msg, len);
574
575 if (ret)
576 goto err;
577 ret = transmit_skb(skb, cf_sk, noblock, timeo);
578 if (ret < 0)
579 /* skb is already freed */
580 return ret;
581
582 return len;
583 err:
584 kfree_skb(skb);
585 return ret;
586 }
587
588 /*
589 * Copied from unix_stream_sendmsg and adapted to CAIF:
590 * Changed removed permission handling and added waiting for flow on
591 * and other minor adaptations.
592 */
593 static int caif_stream_sendmsg(struct socket *sock, struct msghdr *msg,
594 size_t len)
595 {
596 struct sock *sk = sock->sk;
597 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
598 int err, size;
599 struct sk_buff *skb;
600 int sent = 0;
601 long timeo;
602
603 err = -EOPNOTSUPP;
604 if (unlikely(msg->msg_flags&MSG_OOB))
605 goto out_err;
606
607 if (unlikely(msg->msg_namelen))
608 goto out_err;
609
610 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
611 timeo = caif_wait_for_flow_on(cf_sk, 1, timeo, &err);
612
613 if (unlikely(sk->sk_shutdown & SEND_SHUTDOWN))
614 goto pipe_err;
615
616 while (sent < len) {
617
618 size = len-sent;
619
620 if (size > cf_sk->maxframe)
621 size = cf_sk->maxframe;
622
623 /* If size is more than half of sndbuf, chop up message */
624 if (size > ((sk->sk_sndbuf >> 1) - 64))
625 size = (sk->sk_sndbuf >> 1) - 64;
626
627 if (size > SKB_MAX_ALLOC)
628 size = SKB_MAX_ALLOC;
629
630 skb = sock_alloc_send_skb(sk,
631 size + cf_sk->headroom +
632 cf_sk->tailroom,
633 msg->msg_flags&MSG_DONTWAIT,
634 &err);
635 if (skb == NULL)
636 goto out_err;
637
638 skb_reserve(skb, cf_sk->headroom);
639 /*
640 * If you pass two values to the sock_alloc_send_skb
641 * it tries to grab the large buffer with GFP_NOFS
642 * (which can fail easily), and if it fails grab the
643 * fallback size buffer which is under a page and will
644 * succeed. [Alan]
645 */
646 size = min_t(int, size, skb_tailroom(skb));
647
648 err = memcpy_from_msg(skb_put(skb, size), msg, size);
649 if (err) {
650 kfree_skb(skb);
651 goto out_err;
652 }
653 err = transmit_skb(skb, cf_sk,
654 msg->msg_flags&MSG_DONTWAIT, timeo);
655 if (err < 0)
656 /* skb is already freed */
657 goto pipe_err;
658
659 sent += size;
660 }
661
662 return sent;
663
664 pipe_err:
665 if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
666 send_sig(SIGPIPE, current, 0);
667 err = -EPIPE;
668 out_err:
669 return sent ? : err;
670 }
671
672 static int setsockopt(struct socket *sock,
673 int lvl, int opt, char __user *ov, unsigned int ol)
674 {
675 struct sock *sk = sock->sk;
676 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
677 int linksel;
678
679 if (cf_sk->sk.sk_socket->state != SS_UNCONNECTED)
680 return -ENOPROTOOPT;
681
682 switch (opt) {
683 case CAIFSO_LINK_SELECT:
684 if (ol < sizeof(int))
685 return -EINVAL;
686 if (lvl != SOL_CAIF)
687 goto bad_sol;
688 if (copy_from_user(&linksel, ov, sizeof(int)))
689 return -EINVAL;
690 lock_sock(&(cf_sk->sk));
691 cf_sk->conn_req.link_selector = linksel;
692 release_sock(&cf_sk->sk);
693 return 0;
694
695 case CAIFSO_REQ_PARAM:
696 if (lvl != SOL_CAIF)
697 goto bad_sol;
698 if (cf_sk->sk.sk_protocol != CAIFPROTO_UTIL)
699 return -ENOPROTOOPT;
700 lock_sock(&(cf_sk->sk));
701 if (ol > sizeof(cf_sk->conn_req.param.data) ||
702 copy_from_user(&cf_sk->conn_req.param.data, ov, ol)) {
703 release_sock(&cf_sk->sk);
704 return -EINVAL;
705 }
706 cf_sk->conn_req.param.size = ol;
707 release_sock(&cf_sk->sk);
708 return 0;
709
710 default:
711 return -ENOPROTOOPT;
712 }
713
714 return 0;
715 bad_sol:
716 return -ENOPROTOOPT;
717
718 }
719
720 /*
721 * caif_connect() - Connect a CAIF Socket
722 * Copied and modified af_irda.c:irda_connect().
723 *
724 * Note : by consulting "errno", the user space caller may learn the cause
725 * of the failure. Most of them are visible in the function, others may come
726 * from subroutines called and are listed here :
727 * o -EAFNOSUPPORT: bad socket family or type.
728 * o -ESOCKTNOSUPPORT: bad socket type or protocol
729 * o -EINVAL: bad socket address, or CAIF link type
730 * o -ECONNREFUSED: remote end refused the connection.
731 * o -EINPROGRESS: connect request sent but timed out (or non-blocking)
732 * o -EISCONN: already connected.
733 * o -ETIMEDOUT: Connection timed out (send timeout)
734 * o -ENODEV: No link layer to send request
735 * o -ECONNRESET: Received Shutdown indication or lost link layer
736 * o -ENOMEM: Out of memory
737 *
738 * State Strategy:
739 * o sk_state: holds the CAIF_* protocol state, it's updated by
740 * caif_ctrl_cb.
741 * o sock->state: holds the SS_* socket state and is updated by connect and
742 * disconnect.
743 */
744 static int caif_connect(struct socket *sock, struct sockaddr *uaddr,
745 int addr_len, int flags)
746 {
747 struct sock *sk = sock->sk;
748 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
749 long timeo;
750 int err;
751 int ifindex, headroom, tailroom;
752 unsigned int mtu;
753 struct net_device *dev;
754
755 lock_sock(sk);
756
757 err = -EINVAL;
758 if (addr_len < offsetofend(struct sockaddr, sa_family))
759 goto out;
760
761 err = -EAFNOSUPPORT;
762 if (uaddr->sa_family != AF_CAIF)
763 goto out;
764
765 switch (sock->state) {
766 case SS_UNCONNECTED:
767 /* Normal case, a fresh connect */
768 caif_assert(sk->sk_state == CAIF_DISCONNECTED);
769 break;
770 case SS_CONNECTING:
771 switch (sk->sk_state) {
772 case CAIF_CONNECTED:
773 sock->state = SS_CONNECTED;
774 err = -EISCONN;
775 goto out;
776 case CAIF_DISCONNECTED:
777 /* Reconnect allowed */
778 break;
779 case CAIF_CONNECTING:
780 err = -EALREADY;
781 if (flags & O_NONBLOCK)
782 goto out;
783 goto wait_connect;
784 }
785 break;
786 case SS_CONNECTED:
787 caif_assert(sk->sk_state == CAIF_CONNECTED ||
788 sk->sk_state == CAIF_DISCONNECTED);
789 if (sk->sk_shutdown & SHUTDOWN_MASK) {
790 /* Allow re-connect after SHUTDOWN_IND */
791 caif_disconnect_client(sock_net(sk), &cf_sk->layer);
792 caif_free_client(&cf_sk->layer);
793 break;
794 }
795 /* No reconnect on a seqpacket socket */
796 err = -EISCONN;
797 goto out;
798 case SS_DISCONNECTING:
799 case SS_FREE:
800 caif_assert(1); /*Should never happen */
801 break;
802 }
803 sk->sk_state = CAIF_DISCONNECTED;
804 sock->state = SS_UNCONNECTED;
805 sk_stream_kill_queues(&cf_sk->sk);
806
807 err = -EINVAL;
808 if (addr_len != sizeof(struct sockaddr_caif))
809 goto out;
810
811 memcpy(&cf_sk->conn_req.sockaddr, uaddr,
812 sizeof(struct sockaddr_caif));
813
814 /* Move to connecting socket, start sending Connect Requests */
815 sock->state = SS_CONNECTING;
816 sk->sk_state = CAIF_CONNECTING;
817
818 /* Check priority value comming from socket */
819 /* if priority value is out of range it will be ajusted */
820 if (cf_sk->sk.sk_priority > CAIF_PRIO_MAX)
821 cf_sk->conn_req.priority = CAIF_PRIO_MAX;
822 else if (cf_sk->sk.sk_priority < CAIF_PRIO_MIN)
823 cf_sk->conn_req.priority = CAIF_PRIO_MIN;
824 else
825 cf_sk->conn_req.priority = cf_sk->sk.sk_priority;
826
827 /*ifindex = id of the interface.*/
828 cf_sk->conn_req.ifindex = cf_sk->sk.sk_bound_dev_if;
829
830 cf_sk->layer.receive = caif_sktrecv_cb;
831
832 err = caif_connect_client(sock_net(sk), &cf_sk->conn_req,
833 &cf_sk->layer, &ifindex, &headroom, &tailroom);
834
835 if (err < 0) {
836 cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
837 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
838 goto out;
839 }
840
841 err = -ENODEV;
842 rcu_read_lock();
843 dev = dev_get_by_index_rcu(sock_net(sk), ifindex);
844 if (!dev) {
845 rcu_read_unlock();
846 goto out;
847 }
848 cf_sk->headroom = LL_RESERVED_SPACE_EXTRA(dev, headroom);
849 mtu = dev->mtu;
850 rcu_read_unlock();
851
852 cf_sk->tailroom = tailroom;
853 cf_sk->maxframe = mtu - (headroom + tailroom);
854 if (cf_sk->maxframe < 1) {
855 pr_warn("CAIF Interface MTU too small (%d)\n", dev->mtu);
856 err = -ENODEV;
857 goto out;
858 }
859
860 err = -EINPROGRESS;
861 wait_connect:
862
863 if (sk->sk_state != CAIF_CONNECTED && (flags & O_NONBLOCK))
864 goto out;
865
866 timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
867
868 release_sock(sk);
869 err = -ERESTARTSYS;
870 timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
871 sk->sk_state != CAIF_CONNECTING,
872 timeo);
873 lock_sock(sk);
874 if (timeo < 0)
875 goto out; /* -ERESTARTSYS */
876
877 err = -ETIMEDOUT;
878 if (timeo == 0 && sk->sk_state != CAIF_CONNECTED)
879 goto out;
880 if (sk->sk_state != CAIF_CONNECTED) {
881 sock->state = SS_UNCONNECTED;
882 err = sock_error(sk);
883 if (!err)
884 err = -ECONNREFUSED;
885 goto out;
886 }
887 sock->state = SS_CONNECTED;
888 err = 0;
889 out:
890 release_sock(sk);
891 return err;
892 }
893
894 /*
895 * caif_release() - Disconnect a CAIF Socket
896 * Copied and modified af_irda.c:irda_release().
897 */
898 static int caif_release(struct socket *sock)
899 {
900 struct sock *sk = sock->sk;
901 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
902
903 if (!sk)
904 return 0;
905
906 set_tx_flow_off(cf_sk);
907
908 /*
909 * Ensure that packets are not queued after this point in time.
910 * caif_queue_rcv_skb checks SOCK_DEAD holding the queue lock,
911 * this ensures no packets when sock is dead.
912 */
913 spin_lock_bh(&sk->sk_receive_queue.lock);
914 sock_set_flag(sk, SOCK_DEAD);
915 spin_unlock_bh(&sk->sk_receive_queue.lock);
916 sock->sk = NULL;
917
918 WARN_ON(IS_ERR(cf_sk->debugfs_socket_dir));
919 debugfs_remove_recursive(cf_sk->debugfs_socket_dir);
920
921 lock_sock(&(cf_sk->sk));
922 sk->sk_state = CAIF_DISCONNECTED;
923 sk->sk_shutdown = SHUTDOWN_MASK;
924
925 caif_disconnect_client(sock_net(sk), &cf_sk->layer);
926 cf_sk->sk.sk_socket->state = SS_DISCONNECTING;
927 wake_up_interruptible_poll(sk_sleep(sk), EPOLLERR|EPOLLHUP);
928
929 sock_orphan(sk);
930 sk_stream_kill_queues(&cf_sk->sk);
931 release_sock(sk);
932 sock_put(sk);
933 return 0;
934 }
935
936 /* Copied from af_unix.c:unix_poll(), added CAIF tx_flow handling */
937 static __poll_t caif_poll(struct file *file,
938 struct socket *sock, poll_table *wait)
939 {
940 struct sock *sk = sock->sk;
941 __poll_t mask;
942 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
943
944 sock_poll_wait(file, sock, wait);
945 mask = 0;
946
947 /* exceptional events? */
948 if (sk->sk_err)
949 mask |= EPOLLERR;
950 if (sk->sk_shutdown == SHUTDOWN_MASK)
951 mask |= EPOLLHUP;
952 if (sk->sk_shutdown & RCV_SHUTDOWN)
953 mask |= EPOLLRDHUP;
954
955 /* readable? */
956 if (!skb_queue_empty(&sk->sk_receive_queue) ||
957 (sk->sk_shutdown & RCV_SHUTDOWN))
958 mask |= EPOLLIN | EPOLLRDNORM;
959
960 /*
961 * we set writable also when the other side has shut down the
962 * connection. This prevents stuck sockets.
963 */
964 if (sock_writeable(sk) && tx_flow_is_on(cf_sk))
965 mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
966
967 return mask;
968 }
969
970 static const struct proto_ops caif_seqpacket_ops = {
971 .family = PF_CAIF,
972 .owner = THIS_MODULE,
973 .release = caif_release,
974 .bind = sock_no_bind,
975 .connect = caif_connect,
976 .socketpair = sock_no_socketpair,
977 .accept = sock_no_accept,
978 .getname = sock_no_getname,
979 .poll = caif_poll,
980 .ioctl = sock_no_ioctl,
981 .listen = sock_no_listen,
982 .shutdown = sock_no_shutdown,
983 .setsockopt = setsockopt,
984 .getsockopt = sock_no_getsockopt,
985 .sendmsg = caif_seqpkt_sendmsg,
986 .recvmsg = caif_seqpkt_recvmsg,
987 .mmap = sock_no_mmap,
988 .sendpage = sock_no_sendpage,
989 };
990
991 static const struct proto_ops caif_stream_ops = {
992 .family = PF_CAIF,
993 .owner = THIS_MODULE,
994 .release = caif_release,
995 .bind = sock_no_bind,
996 .connect = caif_connect,
997 .socketpair = sock_no_socketpair,
998 .accept = sock_no_accept,
999 .getname = sock_no_getname,
1000 .poll = caif_poll,
1001 .ioctl = sock_no_ioctl,
1002 .listen = sock_no_listen,
1003 .shutdown = sock_no_shutdown,
1004 .setsockopt = setsockopt,
1005 .getsockopt = sock_no_getsockopt,
1006 .sendmsg = caif_stream_sendmsg,
1007 .recvmsg = caif_stream_recvmsg,
1008 .mmap = sock_no_mmap,
1009 .sendpage = sock_no_sendpage,
1010 };
1011
1012 /* This function is called when a socket is finally destroyed. */
1013 static void caif_sock_destructor(struct sock *sk)
1014 {
1015 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
1016 caif_assert(!refcount_read(&sk->sk_wmem_alloc));
1017 caif_assert(sk_unhashed(sk));
1018 caif_assert(!sk->sk_socket);
1019 if (!sock_flag(sk, SOCK_DEAD)) {
1020 pr_debug("Attempt to release alive CAIF socket: %p\n", sk);
1021 return;
1022 }
1023 sk_stream_kill_queues(&cf_sk->sk);
1024 caif_free_client(&cf_sk->layer);
1025 }
1026
1027 static int caif_create(struct net *net, struct socket *sock, int protocol,
1028 int kern)
1029 {
1030 struct sock *sk = NULL;
1031 struct caifsock *cf_sk = NULL;
1032 static struct proto prot = {.name = "PF_CAIF",
1033 .owner = THIS_MODULE,
1034 .obj_size = sizeof(struct caifsock),
1035 .useroffset = offsetof(struct caifsock, conn_req.param),
1036 .usersize = sizeof_field(struct caifsock, conn_req.param)
1037 };
1038
1039 if (!capable(CAP_SYS_ADMIN) && !capable(CAP_NET_ADMIN))
1040 return -EPERM;
1041 /*
1042 * The sock->type specifies the socket type to use.
1043 * The CAIF socket is a packet stream in the sense
1044 * that it is packet based. CAIF trusts the reliability
1045 * of the link, no resending is implemented.
1046 */
1047 if (sock->type == SOCK_SEQPACKET)
1048 sock->ops = &caif_seqpacket_ops;
1049 else if (sock->type == SOCK_STREAM)
1050 sock->ops = &caif_stream_ops;
1051 else
1052 return -ESOCKTNOSUPPORT;
1053
1054 if (protocol < 0 || protocol >= CAIFPROTO_MAX)
1055 return -EPROTONOSUPPORT;
1056 /*
1057 * Set the socket state to unconnected. The socket state
1058 * is really not used at all in the net/core or socket.c but the
1059 * initialization makes sure that sock->state is not uninitialized.
1060 */
1061 sk = sk_alloc(net, PF_CAIF, GFP_KERNEL, &prot, kern);
1062 if (!sk)
1063 return -ENOMEM;
1064
1065 cf_sk = container_of(sk, struct caifsock, sk);
1066
1067 /* Store the protocol */
1068 sk->sk_protocol = (unsigned char) protocol;
1069
1070 /* Initialize default priority for well-known cases */
1071 switch (protocol) {
1072 case CAIFPROTO_AT:
1073 sk->sk_priority = TC_PRIO_CONTROL;
1074 break;
1075 case CAIFPROTO_RFM:
1076 sk->sk_priority = TC_PRIO_INTERACTIVE_BULK;
1077 break;
1078 default:
1079 sk->sk_priority = TC_PRIO_BESTEFFORT;
1080 }
1081
1082 /*
1083 * Lock in order to try to stop someone from opening the socket
1084 * too early.
1085 */
1086 lock_sock(&(cf_sk->sk));
1087
1088 /* Initialize the nozero default sock structure data. */
1089 sock_init_data(sock, sk);
1090 sk->sk_destruct = caif_sock_destructor;
1091
1092 mutex_init(&cf_sk->readlock); /* single task reading lock */
1093 cf_sk->layer.ctrlcmd = caif_ctrl_cb;
1094 cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
1095 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
1096
1097 set_tx_flow_off(cf_sk);
1098 set_rx_flow_on(cf_sk);
1099
1100 /* Set default options on configuration */
1101 cf_sk->conn_req.link_selector = CAIF_LINK_LOW_LATENCY;
1102 cf_sk->conn_req.protocol = protocol;
1103 release_sock(&cf_sk->sk);
1104 return 0;
1105 }
1106
1107
1108 static const struct net_proto_family caif_family_ops = {
1109 .family = PF_CAIF,
1110 .create = caif_create,
1111 .owner = THIS_MODULE,
1112 };
1113
1114 static int __init caif_sktinit_module(void)
1115 {
1116 return sock_register(&caif_family_ops);
1117 }
1118
1119 static void __exit caif_sktexit_module(void)
1120 {
1121 sock_unregister(PF_CAIF);
1122 }
1123 module_init(caif_sktinit_module);
1124 module_exit(caif_sktexit_module);
Linux with added FPC-III support