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
rx_flow_is_on(struct caifsock * cf_sk)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
tx_flow_is_on(struct caifsock * cf_sk)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
set_rx_flow_off(struct caifsock * cf_sk)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
set_rx_flow_on(struct caifsock * cf_sk)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
set_tx_flow_off(struct caifsock * cf_sk)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
set_tx_flow_on(struct caifsock * cf_sk)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
caif_read_lock(struct sock * sk)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
caif_read_unlock(struct sock * sk)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
sk_rcvbuf_lowwater(struct caifsock * cf_sk)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
caif_flow_ctrl(struct sock * sk,int mode)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 */
caif_queue_rcv_skb(struct sock * sk,struct sk_buff * skb)124 static int caif_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
125 {
126 int err;
127 int skb_len;
128 unsigned long flags;
129 struct sk_buff_head *list = &sk->sk_receive_queue;
130 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
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 return err;
144 if (!sk_rmem_schedule(sk, skb, skb->truesize) && rx_flow_is_on(cf_sk)) {
145 set_rx_flow_off(cf_sk);
146 net_dbg_ratelimited("sending flow OFF due to rmem_schedule\n");
147 caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ);
148 }
149 skb->dev = NULL;
150 skb_set_owner_r(skb, sk);
151 /* Cache the SKB length before we tack it onto the receive
152 * queue. Once it is added it no longer belongs to us and
153 * may be freed by other threads of control pulling packets
154 * from the queue.
155 */
156 skb_len = skb->len;
157 spin_lock_irqsave(&list->lock, flags);
158 if (!sock_flag(sk, SOCK_DEAD))
159 __skb_queue_tail(list, skb);
160 spin_unlock_irqrestore(&list->lock, flags);
161
162 if (!sock_flag(sk, SOCK_DEAD))
163 sk->sk_data_ready(sk, skb_len);
164 else
165 kfree_skb(skb);
166 return 0;
167 }
168
169 /* Packet Receive Callback function called from CAIF Stack */
caif_sktrecv_cb(struct cflayer * layr,struct cfpkt * pkt)170 static int caif_sktrecv_cb(struct cflayer *layr, struct cfpkt *pkt)
171 {
172 struct caifsock *cf_sk;
173 struct sk_buff *skb;
174
175 cf_sk = container_of(layr, struct caifsock, layer);
176 skb = cfpkt_tonative(pkt);
177
178 if (unlikely(cf_sk->sk.sk_state != CAIF_CONNECTED)) {
179 kfree_skb(skb);
180 return 0;
181 }
182 caif_queue_rcv_skb(&cf_sk->sk, skb);
183 return 0;
184 }
185
cfsk_hold(struct cflayer * layr)186 static void cfsk_hold(struct cflayer *layr)
187 {
188 struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
189 sock_hold(&cf_sk->sk);
190 }
191
cfsk_put(struct cflayer * layr)192 static void cfsk_put(struct cflayer *layr)
193 {
194 struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
195 sock_put(&cf_sk->sk);
196 }
197
198 /* Packet Control Callback function called from CAIF */
caif_ctrl_cb(struct cflayer * layr,enum caif_ctrlcmd flow,int phyid)199 static void caif_ctrl_cb(struct cflayer *layr,
200 enum caif_ctrlcmd flow,
201 int phyid)
202 {
203 struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
204 switch (flow) {
205 case CAIF_CTRLCMD_FLOW_ON_IND:
206 /* OK from modem to start sending again */
207 set_tx_flow_on(cf_sk);
208 cf_sk->sk.sk_state_change(&cf_sk->sk);
209 break;
210
211 case CAIF_CTRLCMD_FLOW_OFF_IND:
212 /* Modem asks us to shut up */
213 set_tx_flow_off(cf_sk);
214 cf_sk->sk.sk_state_change(&cf_sk->sk);
215 break;
216
217 case CAIF_CTRLCMD_INIT_RSP:
218 /* We're now connected */
219 caif_client_register_refcnt(&cf_sk->layer,
220 cfsk_hold, cfsk_put);
221 cf_sk->sk.sk_state = CAIF_CONNECTED;
222 set_tx_flow_on(cf_sk);
223 cf_sk->sk.sk_shutdown = 0;
224 cf_sk->sk.sk_state_change(&cf_sk->sk);
225 break;
226
227 case CAIF_CTRLCMD_DEINIT_RSP:
228 /* We're now disconnected */
229 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
230 cf_sk->sk.sk_state_change(&cf_sk->sk);
231 break;
232
233 case CAIF_CTRLCMD_INIT_FAIL_RSP:
234 /* Connect request failed */
235 cf_sk->sk.sk_err = ECONNREFUSED;
236 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
237 cf_sk->sk.sk_shutdown = SHUTDOWN_MASK;
238 /*
239 * Socket "standards" seems to require POLLOUT to
240 * be set at connect failure.
241 */
242 set_tx_flow_on(cf_sk);
243 cf_sk->sk.sk_state_change(&cf_sk->sk);
244 break;
245
246 case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
247 /* Modem has closed this connection, or device is down. */
248 cf_sk->sk.sk_shutdown = SHUTDOWN_MASK;
249 cf_sk->sk.sk_err = ECONNRESET;
250 set_rx_flow_on(cf_sk);
251 cf_sk->sk.sk_error_report(&cf_sk->sk);
252 break;
253
254 default:
255 pr_debug("Unexpected flow command %d\n", flow);
256 }
257 }
258
caif_check_flow_release(struct sock * sk)259 static void caif_check_flow_release(struct sock *sk)
260 {
261 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
262
263 if (rx_flow_is_on(cf_sk))
264 return;
265
266 if (atomic_read(&sk->sk_rmem_alloc) <= sk_rcvbuf_lowwater(cf_sk)) {
267 set_rx_flow_on(cf_sk);
268 caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_ON_REQ);
269 }
270 }
271
272 /*
273 * Copied from unix_dgram_recvmsg, but removed credit checks,
274 * changed locking, address handling and added MSG_TRUNC.
275 */
caif_seqpkt_recvmsg(struct kiocb * iocb,struct socket * sock,struct msghdr * m,size_t len,int flags)276 static int caif_seqpkt_recvmsg(struct kiocb *iocb, struct socket *sock,
277 struct msghdr *m, size_t len, int flags)
278
279 {
280 struct sock *sk = sock->sk;
281 struct sk_buff *skb;
282 int ret;
283 int copylen;
284
285 ret = -EOPNOTSUPP;
286 if (m->msg_flags&MSG_OOB)
287 goto read_error;
288
289 m->msg_namelen = 0;
290
291 skb = skb_recv_datagram(sk, flags, 0 , &ret);
292 if (!skb)
293 goto read_error;
294 copylen = skb->len;
295 if (len < copylen) {
296 m->msg_flags |= MSG_TRUNC;
297 copylen = len;
298 }
299
300 ret = skb_copy_datagram_iovec(skb, 0, m->msg_iov, copylen);
301 if (ret)
302 goto out_free;
303
304 ret = (flags & MSG_TRUNC) ? skb->len : copylen;
305 out_free:
306 skb_free_datagram(sk, skb);
307 caif_check_flow_release(sk);
308 return ret;
309
310 read_error:
311 return ret;
312 }
313
314
315 /* Copied from unix_stream_wait_data, identical except for lock call. */
caif_stream_data_wait(struct sock * sk,long timeo)316 static long caif_stream_data_wait(struct sock *sk, long timeo)
317 {
318 DEFINE_WAIT(wait);
319 lock_sock(sk);
320
321 for (;;) {
322 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
323
324 if (!skb_queue_empty(&sk->sk_receive_queue) ||
325 sk->sk_err ||
326 sk->sk_state != CAIF_CONNECTED ||
327 sock_flag(sk, SOCK_DEAD) ||
328 (sk->sk_shutdown & RCV_SHUTDOWN) ||
329 signal_pending(current) ||
330 !timeo)
331 break;
332
333 set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
334 release_sock(sk);
335 timeo = schedule_timeout(timeo);
336 lock_sock(sk);
337
338 if (sock_flag(sk, SOCK_DEAD))
339 break;
340
341 clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
342 }
343
344 finish_wait(sk_sleep(sk), &wait);
345 release_sock(sk);
346 return timeo;
347 }
348
349
350 /*
351 * Copied from unix_stream_recvmsg, but removed credit checks,
352 * changed locking calls, changed address handling.
353 */
caif_stream_recvmsg(struct kiocb * iocb,struct socket * sock,struct msghdr * msg,size_t size,int flags)354 static int caif_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
355 struct msghdr *msg, size_t size,
356 int flags)
357 {
358 struct sock *sk = sock->sk;
359 int copied = 0;
360 int target;
361 int err = 0;
362 long timeo;
363
364 err = -EOPNOTSUPP;
365 if (flags&MSG_OOB)
366 goto out;
367
368 msg->msg_namelen = 0;
369
370 /*
371 * Lock the socket to prevent queue disordering
372 * while sleeps in memcpy_tomsg
373 */
374 err = -EAGAIN;
375 if (sk->sk_state == CAIF_CONNECTING)
376 goto out;
377
378 caif_read_lock(sk);
379 target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
380 timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT);
381
382 do {
383 int chunk;
384 struct sk_buff *skb;
385
386 lock_sock(sk);
387 if (sock_flag(sk, SOCK_DEAD)) {
388 err = -ECONNRESET;
389 goto unlock;
390 }
391 skb = skb_dequeue(&sk->sk_receive_queue);
392 caif_check_flow_release(sk);
393
394 if (skb == NULL) {
395 if (copied >= target)
396 goto unlock;
397 /*
398 * POSIX 1003.1g mandates this order.
399 */
400 err = sock_error(sk);
401 if (err)
402 goto unlock;
403 err = -ECONNRESET;
404 if (sk->sk_shutdown & RCV_SHUTDOWN)
405 goto unlock;
406
407 err = -EPIPE;
408 if (sk->sk_state != CAIF_CONNECTED)
409 goto unlock;
410 if (sock_flag(sk, SOCK_DEAD))
411 goto unlock;
412
413 release_sock(sk);
414
415 err = -EAGAIN;
416 if (!timeo)
417 break;
418
419 caif_read_unlock(sk);
420
421 timeo = caif_stream_data_wait(sk, timeo);
422
423 if (signal_pending(current)) {
424 err = sock_intr_errno(timeo);
425 goto out;
426 }
427 caif_read_lock(sk);
428 continue;
429 unlock:
430 release_sock(sk);
431 break;
432 }
433 release_sock(sk);
434 chunk = min_t(unsigned int, skb->len, size);
435 if (memcpy_toiovec(msg->msg_iov, skb->data, chunk)) {
436 skb_queue_head(&sk->sk_receive_queue, skb);
437 if (copied == 0)
438 copied = -EFAULT;
439 break;
440 }
441 copied += chunk;
442 size -= chunk;
443
444 /* Mark read part of skb as used */
445 if (!(flags & MSG_PEEK)) {
446 skb_pull(skb, chunk);
447
448 /* put the skb back if we didn't use it up. */
449 if (skb->len) {
450 skb_queue_head(&sk->sk_receive_queue, skb);
451 break;
452 }
453 kfree_skb(skb);
454
455 } else {
456 /*
457 * It is questionable, see note in unix_dgram_recvmsg.
458 */
459 /* put message back and return */
460 skb_queue_head(&sk->sk_receive_queue, skb);
461 break;
462 }
463 } while (size);
464 caif_read_unlock(sk);
465
466 out:
467 return copied ? : err;
468 }
469
470 /*
471 * Copied from sock.c:sock_wait_for_wmem, but change to wait for
472 * CAIF flow-on and sock_writable.
473 */
caif_wait_for_flow_on(struct caifsock * cf_sk,int wait_writeable,long timeo,int * err)474 static long caif_wait_for_flow_on(struct caifsock *cf_sk,
475 int wait_writeable, long timeo, int *err)
476 {
477 struct sock *sk = &cf_sk->sk;
478 DEFINE_WAIT(wait);
479 for (;;) {
480 *err = 0;
481 if (tx_flow_is_on(cf_sk) &&
482 (!wait_writeable || sock_writeable(&cf_sk->sk)))
483 break;
484 *err = -ETIMEDOUT;
485 if (!timeo)
486 break;
487 *err = -ERESTARTSYS;
488 if (signal_pending(current))
489 break;
490 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
491 *err = -ECONNRESET;
492 if (sk->sk_shutdown & SHUTDOWN_MASK)
493 break;
494 *err = -sk->sk_err;
495 if (sk->sk_err)
496 break;
497 *err = -EPIPE;
498 if (cf_sk->sk.sk_state != CAIF_CONNECTED)
499 break;
500 timeo = schedule_timeout(timeo);
501 }
502 finish_wait(sk_sleep(sk), &wait);
503 return timeo;
504 }
505
506 /*
507 * Transmit a SKB. The device may temporarily request re-transmission
508 * by returning EAGAIN.
509 */
transmit_skb(struct sk_buff * skb,struct caifsock * cf_sk,int noblock,long timeo)510 static int transmit_skb(struct sk_buff *skb, struct caifsock *cf_sk,
511 int noblock, long timeo)
512 {
513 struct cfpkt *pkt;
514
515 pkt = cfpkt_fromnative(CAIF_DIR_OUT, skb);
516 memset(skb->cb, 0, sizeof(struct caif_payload_info));
517 cfpkt_set_prio(pkt, cf_sk->sk.sk_priority);
518
519 if (cf_sk->layer.dn == NULL) {
520 kfree_skb(skb);
521 return -EINVAL;
522 }
523
524 return cf_sk->layer.dn->transmit(cf_sk->layer.dn, pkt);
525 }
526
527 /* Copied from af_unix:unix_dgram_sendmsg, and adapted to CAIF */
caif_seqpkt_sendmsg(struct kiocb * kiocb,struct socket * sock,struct msghdr * msg,size_t len)528 static int caif_seqpkt_sendmsg(struct kiocb *kiocb, struct socket *sock,
529 struct msghdr *msg, size_t len)
530 {
531 struct sock *sk = sock->sk;
532 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
533 int buffer_size;
534 int ret = 0;
535 struct sk_buff *skb = NULL;
536 int noblock;
537 long timeo;
538 caif_assert(cf_sk);
539 ret = sock_error(sk);
540 if (ret)
541 goto err;
542
543 ret = -EOPNOTSUPP;
544 if (msg->msg_flags&MSG_OOB)
545 goto err;
546
547 ret = -EOPNOTSUPP;
548 if (msg->msg_namelen)
549 goto err;
550
551 ret = -EINVAL;
552 if (unlikely(msg->msg_iov->iov_base == NULL))
553 goto err;
554 noblock = msg->msg_flags & MSG_DONTWAIT;
555
556 timeo = sock_sndtimeo(sk, noblock);
557 timeo = caif_wait_for_flow_on(container_of(sk, struct caifsock, sk),
558 1, timeo, &ret);
559
560 if (ret)
561 goto err;
562 ret = -EPIPE;
563 if (cf_sk->sk.sk_state != CAIF_CONNECTED ||
564 sock_flag(sk, SOCK_DEAD) ||
565 (sk->sk_shutdown & RCV_SHUTDOWN))
566 goto err;
567
568 /* Error if trying to write more than maximum frame size. */
569 ret = -EMSGSIZE;
570 if (len > cf_sk->maxframe && cf_sk->sk.sk_protocol != CAIFPROTO_RFM)
571 goto err;
572
573 buffer_size = len + cf_sk->headroom + cf_sk->tailroom;
574
575 ret = -ENOMEM;
576 skb = sock_alloc_send_skb(sk, buffer_size, noblock, &ret);
577
578 if (!skb || skb_tailroom(skb) < buffer_size)
579 goto err;
580
581 skb_reserve(skb, cf_sk->headroom);
582
583 ret = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
584
585 if (ret)
586 goto err;
587 ret = transmit_skb(skb, cf_sk, noblock, timeo);
588 if (ret < 0)
589 /* skb is already freed */
590 return ret;
591
592 return len;
593 err:
594 kfree_skb(skb);
595 return ret;
596 }
597
598 /*
599 * Copied from unix_stream_sendmsg and adapted to CAIF:
600 * Changed removed permission handling and added waiting for flow on
601 * and other minor adaptations.
602 */
caif_stream_sendmsg(struct kiocb * kiocb,struct socket * sock,struct msghdr * msg,size_t len)603 static int caif_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
604 struct msghdr *msg, size_t len)
605 {
606 struct sock *sk = sock->sk;
607 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
608 int err, size;
609 struct sk_buff *skb;
610 int sent = 0;
611 long timeo;
612
613 err = -EOPNOTSUPP;
614 if (unlikely(msg->msg_flags&MSG_OOB))
615 goto out_err;
616
617 if (unlikely(msg->msg_namelen))
618 goto out_err;
619
620 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
621 timeo = caif_wait_for_flow_on(cf_sk, 1, timeo, &err);
622
623 if (unlikely(sk->sk_shutdown & SEND_SHUTDOWN))
624 goto pipe_err;
625
626 while (sent < len) {
627
628 size = len-sent;
629
630 if (size > cf_sk->maxframe)
631 size = cf_sk->maxframe;
632
633 /* If size is more than half of sndbuf, chop up message */
634 if (size > ((sk->sk_sndbuf >> 1) - 64))
635 size = (sk->sk_sndbuf >> 1) - 64;
636
637 if (size > SKB_MAX_ALLOC)
638 size = SKB_MAX_ALLOC;
639
640 skb = sock_alloc_send_skb(sk,
641 size + cf_sk->headroom +
642 cf_sk->tailroom,
643 msg->msg_flags&MSG_DONTWAIT,
644 &err);
645 if (skb == NULL)
646 goto out_err;
647
648 skb_reserve(skb, cf_sk->headroom);
649 /*
650 * If you pass two values to the sock_alloc_send_skb
651 * it tries to grab the large buffer with GFP_NOFS
652 * (which can fail easily), and if it fails grab the
653 * fallback size buffer which is under a page and will
654 * succeed. [Alan]
655 */
656 size = min_t(int, size, skb_tailroom(skb));
657
658 err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size);
659 if (err) {
660 kfree_skb(skb);
661 goto out_err;
662 }
663 err = transmit_skb(skb, cf_sk,
664 msg->msg_flags&MSG_DONTWAIT, timeo);
665 if (err < 0)
666 /* skb is already freed */
667 goto pipe_err;
668
669 sent += size;
670 }
671
672 return sent;
673
674 pipe_err:
675 if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
676 send_sig(SIGPIPE, current, 0);
677 err = -EPIPE;
678 out_err:
679 return sent ? : err;
680 }
681
setsockopt(struct socket * sock,int lvl,int opt,char __user * ov,unsigned int ol)682 static int setsockopt(struct socket *sock,
683 int lvl, int opt, char __user *ov, unsigned int ol)
684 {
685 struct sock *sk = sock->sk;
686 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
687 int linksel;
688
689 if (cf_sk->sk.sk_socket->state != SS_UNCONNECTED)
690 return -ENOPROTOOPT;
691
692 switch (opt) {
693 case CAIFSO_LINK_SELECT:
694 if (ol < sizeof(int))
695 return -EINVAL;
696 if (lvl != SOL_CAIF)
697 goto bad_sol;
698 if (copy_from_user(&linksel, ov, sizeof(int)))
699 return -EINVAL;
700 lock_sock(&(cf_sk->sk));
701 cf_sk->conn_req.link_selector = linksel;
702 release_sock(&cf_sk->sk);
703 return 0;
704
705 case CAIFSO_REQ_PARAM:
706 if (lvl != SOL_CAIF)
707 goto bad_sol;
708 if (cf_sk->sk.sk_protocol != CAIFPROTO_UTIL)
709 return -ENOPROTOOPT;
710 lock_sock(&(cf_sk->sk));
711 if (ol > sizeof(cf_sk->conn_req.param.data) ||
712 copy_from_user(&cf_sk->conn_req.param.data, ov, ol)) {
713 release_sock(&cf_sk->sk);
714 return -EINVAL;
715 }
716 cf_sk->conn_req.param.size = ol;
717 release_sock(&cf_sk->sk);
718 return 0;
719
720 default:
721 return -ENOPROTOOPT;
722 }
723
724 return 0;
725 bad_sol:
726 return -ENOPROTOOPT;
727
728 }
729
730 /*
731 * caif_connect() - Connect a CAIF Socket
732 * Copied and modified af_irda.c:irda_connect().
733 *
734 * Note : by consulting "errno", the user space caller may learn the cause
735 * of the failure. Most of them are visible in the function, others may come
736 * from subroutines called and are listed here :
737 * o -EAFNOSUPPORT: bad socket family or type.
738 * o -ESOCKTNOSUPPORT: bad socket type or protocol
739 * o -EINVAL: bad socket address, or CAIF link type
740 * o -ECONNREFUSED: remote end refused the connection.
741 * o -EINPROGRESS: connect request sent but timed out (or non-blocking)
742 * o -EISCONN: already connected.
743 * o -ETIMEDOUT: Connection timed out (send timeout)
744 * o -ENODEV: No link layer to send request
745 * o -ECONNRESET: Received Shutdown indication or lost link layer
746 * o -ENOMEM: Out of memory
747 *
748 * State Strategy:
749 * o sk_state: holds the CAIF_* protocol state, it's updated by
750 * caif_ctrl_cb.
751 * o sock->state: holds the SS_* socket state and is updated by connect and
752 * disconnect.
753 */
caif_connect(struct socket * sock,struct sockaddr * uaddr,int addr_len,int flags)754 static int caif_connect(struct socket *sock, struct sockaddr *uaddr,
755 int addr_len, int flags)
756 {
757 struct sock *sk = sock->sk;
758 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
759 long timeo;
760 int err;
761 int ifindex, headroom, tailroom;
762 unsigned int mtu;
763 struct net_device *dev;
764
765 lock_sock(sk);
766
767 err = -EAFNOSUPPORT;
768 if (uaddr->sa_family != AF_CAIF)
769 goto out;
770
771 switch (sock->state) {
772 case SS_UNCONNECTED:
773 /* Normal case, a fresh connect */
774 caif_assert(sk->sk_state == CAIF_DISCONNECTED);
775 break;
776 case SS_CONNECTING:
777 switch (sk->sk_state) {
778 case CAIF_CONNECTED:
779 sock->state = SS_CONNECTED;
780 err = -EISCONN;
781 goto out;
782 case CAIF_DISCONNECTED:
783 /* Reconnect allowed */
784 break;
785 case CAIF_CONNECTING:
786 err = -EALREADY;
787 if (flags & O_NONBLOCK)
788 goto out;
789 goto wait_connect;
790 }
791 break;
792 case SS_CONNECTED:
793 caif_assert(sk->sk_state == CAIF_CONNECTED ||
794 sk->sk_state == CAIF_DISCONNECTED);
795 if (sk->sk_shutdown & SHUTDOWN_MASK) {
796 /* Allow re-connect after SHUTDOWN_IND */
797 caif_disconnect_client(sock_net(sk), &cf_sk->layer);
798 caif_free_client(&cf_sk->layer);
799 break;
800 }
801 /* No reconnect on a seqpacket socket */
802 err = -EISCONN;
803 goto out;
804 case SS_DISCONNECTING:
805 case SS_FREE:
806 caif_assert(1); /*Should never happen */
807 break;
808 }
809 sk->sk_state = CAIF_DISCONNECTED;
810 sock->state = SS_UNCONNECTED;
811 sk_stream_kill_queues(&cf_sk->sk);
812
813 err = -EINVAL;
814 if (addr_len != sizeof(struct sockaddr_caif))
815 goto out;
816
817 memcpy(&cf_sk->conn_req.sockaddr, uaddr,
818 sizeof(struct sockaddr_caif));
819
820 /* Move to connecting socket, start sending Connect Requests */
821 sock->state = SS_CONNECTING;
822 sk->sk_state = CAIF_CONNECTING;
823
824 /* Check priority value comming from socket */
825 /* if priority value is out of range it will be ajusted */
826 if (cf_sk->sk.sk_priority > CAIF_PRIO_MAX)
827 cf_sk->conn_req.priority = CAIF_PRIO_MAX;
828 else if (cf_sk->sk.sk_priority < CAIF_PRIO_MIN)
829 cf_sk->conn_req.priority = CAIF_PRIO_MIN;
830 else
831 cf_sk->conn_req.priority = cf_sk->sk.sk_priority;
832
833 /*ifindex = id of the interface.*/
834 cf_sk->conn_req.ifindex = cf_sk->sk.sk_bound_dev_if;
835
836 cf_sk->layer.receive = caif_sktrecv_cb;
837
838 err = caif_connect_client(sock_net(sk), &cf_sk->conn_req,
839 &cf_sk->layer, &ifindex, &headroom, &tailroom);
840
841 if (err < 0) {
842 cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
843 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
844 goto out;
845 }
846
847 err = -ENODEV;
848 rcu_read_lock();
849 dev = dev_get_by_index_rcu(sock_net(sk), ifindex);
850 if (!dev) {
851 rcu_read_unlock();
852 goto out;
853 }
854 cf_sk->headroom = LL_RESERVED_SPACE_EXTRA(dev, headroom);
855 mtu = dev->mtu;
856 rcu_read_unlock();
857
858 cf_sk->tailroom = tailroom;
859 cf_sk->maxframe = mtu - (headroom + tailroom);
860 if (cf_sk->maxframe < 1) {
861 pr_warn("CAIF Interface MTU too small (%d)\n", dev->mtu);
862 err = -ENODEV;
863 goto out;
864 }
865
866 err = -EINPROGRESS;
867 wait_connect:
868
869 if (sk->sk_state != CAIF_CONNECTED && (flags & O_NONBLOCK))
870 goto out;
871
872 timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
873
874 release_sock(sk);
875 err = -ERESTARTSYS;
876 timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
877 sk->sk_state != CAIF_CONNECTING,
878 timeo);
879 lock_sock(sk);
880 if (timeo < 0)
881 goto out; /* -ERESTARTSYS */
882
883 err = -ETIMEDOUT;
884 if (timeo == 0 && sk->sk_state != CAIF_CONNECTED)
885 goto out;
886 if (sk->sk_state != CAIF_CONNECTED) {
887 sock->state = SS_UNCONNECTED;
888 err = sock_error(sk);
889 if (!err)
890 err = -ECONNREFUSED;
891 goto out;
892 }
893 sock->state = SS_CONNECTED;
894 err = 0;
895 out:
896 release_sock(sk);
897 return err;
898 }
899
900 /*
901 * caif_release() - Disconnect a CAIF Socket
902 * Copied and modified af_irda.c:irda_release().
903 */
caif_release(struct socket * sock)904 static int caif_release(struct socket *sock)
905 {
906 struct sock *sk = sock->sk;
907 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
908
909 if (!sk)
910 return 0;
911
912 set_tx_flow_off(cf_sk);
913
914 /*
915 * Ensure that packets are not queued after this point in time.
916 * caif_queue_rcv_skb checks SOCK_DEAD holding the queue lock,
917 * this ensures no packets when sock is dead.
918 */
919 spin_lock_bh(&sk->sk_receive_queue.lock);
920 sock_set_flag(sk, SOCK_DEAD);
921 spin_unlock_bh(&sk->sk_receive_queue.lock);
922 sock->sk = NULL;
923
924 WARN_ON(IS_ERR(cf_sk->debugfs_socket_dir));
925 if (cf_sk->debugfs_socket_dir != NULL)
926 debugfs_remove_recursive(cf_sk->debugfs_socket_dir);
927
928 lock_sock(&(cf_sk->sk));
929 sk->sk_state = CAIF_DISCONNECTED;
930 sk->sk_shutdown = SHUTDOWN_MASK;
931
932 caif_disconnect_client(sock_net(sk), &cf_sk->layer);
933 cf_sk->sk.sk_socket->state = SS_DISCONNECTING;
934 wake_up_interruptible_poll(sk_sleep(sk), POLLERR|POLLHUP);
935
936 sock_orphan(sk);
937 sk_stream_kill_queues(&cf_sk->sk);
938 release_sock(sk);
939 sock_put(sk);
940 return 0;
941 }
942
943 /* Copied from af_unix.c:unix_poll(), added CAIF tx_flow handling */
caif_poll(struct file * file,struct socket * sock,poll_table * wait)944 static unsigned int caif_poll(struct file *file,
945 struct socket *sock, poll_table *wait)
946 {
947 struct sock *sk = sock->sk;
948 unsigned int mask;
949 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
950
951 sock_poll_wait(file, sk_sleep(sk), wait);
952 mask = 0;
953
954 /* exceptional events? */
955 if (sk->sk_err)
956 mask |= POLLERR;
957 if (sk->sk_shutdown == SHUTDOWN_MASK)
958 mask |= POLLHUP;
959 if (sk->sk_shutdown & RCV_SHUTDOWN)
960 mask |= POLLRDHUP;
961
962 /* readable? */
963 if (!skb_queue_empty(&sk->sk_receive_queue) ||
964 (sk->sk_shutdown & RCV_SHUTDOWN))
965 mask |= POLLIN | POLLRDNORM;
966
967 /*
968 * we set writable also when the other side has shut down the
969 * connection. This prevents stuck sockets.
970 */
971 if (sock_writeable(sk) && tx_flow_is_on(cf_sk))
972 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
973
974 return mask;
975 }
976
977 static const struct proto_ops caif_seqpacket_ops = {
978 .family = PF_CAIF,
979 .owner = THIS_MODULE,
980 .release = caif_release,
981 .bind = sock_no_bind,
982 .connect = caif_connect,
983 .socketpair = sock_no_socketpair,
984 .accept = sock_no_accept,
985 .getname = sock_no_getname,
986 .poll = caif_poll,
987 .ioctl = sock_no_ioctl,
988 .listen = sock_no_listen,
989 .shutdown = sock_no_shutdown,
990 .setsockopt = setsockopt,
991 .getsockopt = sock_no_getsockopt,
992 .sendmsg = caif_seqpkt_sendmsg,
993 .recvmsg = caif_seqpkt_recvmsg,
994 .mmap = sock_no_mmap,
995 .sendpage = sock_no_sendpage,
996 };
997
998 static const struct proto_ops caif_stream_ops = {
999 .family = PF_CAIF,
1000 .owner = THIS_MODULE,
1001 .release = caif_release,
1002 .bind = sock_no_bind,
1003 .connect = caif_connect,
1004 .socketpair = sock_no_socketpair,
1005 .accept = sock_no_accept,
1006 .getname = sock_no_getname,
1007 .poll = caif_poll,
1008 .ioctl = sock_no_ioctl,
1009 .listen = sock_no_listen,
1010 .shutdown = sock_no_shutdown,
1011 .setsockopt = setsockopt,
1012 .getsockopt = sock_no_getsockopt,
1013 .sendmsg = caif_stream_sendmsg,
1014 .recvmsg = caif_stream_recvmsg,
1015 .mmap = sock_no_mmap,
1016 .sendpage = sock_no_sendpage,
1017 };
1018
1019 /* This function is called when a socket is finally destroyed. */
caif_sock_destructor(struct sock * sk)1020 static void caif_sock_destructor(struct sock *sk)
1021 {
1022 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
1023 caif_assert(!atomic_read(&sk->sk_wmem_alloc));
1024 caif_assert(sk_unhashed(sk));
1025 caif_assert(!sk->sk_socket);
1026 if (!sock_flag(sk, SOCK_DEAD)) {
1027 pr_debug("Attempt to release alive CAIF socket: %p\n", sk);
1028 return;
1029 }
1030 sk_stream_kill_queues(&cf_sk->sk);
1031 caif_free_client(&cf_sk->layer);
1032 }
1033
caif_create(struct net * net,struct socket * sock,int protocol,int kern)1034 static int caif_create(struct net *net, struct socket *sock, int protocol,
1035 int kern)
1036 {
1037 struct sock *sk = NULL;
1038 struct caifsock *cf_sk = NULL;
1039 static struct proto prot = {.name = "PF_CAIF",
1040 .owner = THIS_MODULE,
1041 .obj_size = sizeof(struct caifsock),
1042 };
1043
1044 if (!capable(CAP_SYS_ADMIN) && !capable(CAP_NET_ADMIN))
1045 return -EPERM;
1046 /*
1047 * The sock->type specifies the socket type to use.
1048 * The CAIF socket is a packet stream in the sense
1049 * that it is packet based. CAIF trusts the reliability
1050 * of the link, no resending is implemented.
1051 */
1052 if (sock->type == SOCK_SEQPACKET)
1053 sock->ops = &caif_seqpacket_ops;
1054 else if (sock->type == SOCK_STREAM)
1055 sock->ops = &caif_stream_ops;
1056 else
1057 return -ESOCKTNOSUPPORT;
1058
1059 if (protocol < 0 || protocol >= CAIFPROTO_MAX)
1060 return -EPROTONOSUPPORT;
1061 /*
1062 * Set the socket state to unconnected. The socket state
1063 * is really not used at all in the net/core or socket.c but the
1064 * initialization makes sure that sock->state is not uninitialized.
1065 */
1066 sk = sk_alloc(net, PF_CAIF, GFP_KERNEL, &prot);
1067 if (!sk)
1068 return -ENOMEM;
1069
1070 cf_sk = container_of(sk, struct caifsock, sk);
1071
1072 /* Store the protocol */
1073 sk->sk_protocol = (unsigned char) protocol;
1074
1075 /* Initialize default priority for well-known cases */
1076 switch (protocol) {
1077 case CAIFPROTO_AT:
1078 sk->sk_priority = TC_PRIO_CONTROL;
1079 break;
1080 case CAIFPROTO_RFM:
1081 sk->sk_priority = TC_PRIO_INTERACTIVE_BULK;
1082 break;
1083 default:
1084 sk->sk_priority = TC_PRIO_BESTEFFORT;
1085 }
1086
1087 /*
1088 * Lock in order to try to stop someone from opening the socket
1089 * too early.
1090 */
1091 lock_sock(&(cf_sk->sk));
1092
1093 /* Initialize the nozero default sock structure data. */
1094 sock_init_data(sock, sk);
1095 sk->sk_destruct = caif_sock_destructor;
1096
1097 mutex_init(&cf_sk->readlock); /* single task reading lock */
1098 cf_sk->layer.ctrlcmd = caif_ctrl_cb;
1099 cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
1100 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
1101
1102 set_tx_flow_off(cf_sk);
1103 set_rx_flow_on(cf_sk);
1104
1105 /* Set default options on configuration */
1106 cf_sk->conn_req.link_selector = CAIF_LINK_LOW_LATENCY;
1107 cf_sk->conn_req.protocol = protocol;
1108 release_sock(&cf_sk->sk);
1109 return 0;
1110 }
1111
1112
1113 static struct net_proto_family caif_family_ops = {
1114 .family = PF_CAIF,
1115 .create = caif_create,
1116 .owner = THIS_MODULE,
1117 };
1118
caif_sktinit_module(void)1119 static int __init caif_sktinit_module(void)
1120 {
1121 int err = sock_register(&caif_family_ops);
1122 if (!err)
1123 return err;
1124 return 0;
1125 }
1126
caif_sktexit_module(void)1127 static void __exit caif_sktexit_module(void)
1128 {
1129 sock_unregister(PF_CAIF);
1130 }
1131 module_init(caif_sktinit_module);
1132 module_exit(caif_sktexit_module);
1133