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TOMOYO Linux Cross Reference
Linux/net/caif/caif_socket.c

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  1 /*
  2  * Copyright (C) ST-Ericsson AB 2010
  3  * Author:      Sjur Brendeland sjur.brandeland@stericsson.com
  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         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 */
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 
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 
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 */
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 
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  */
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. */
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                 clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
338         }
339 
340         finish_wait(sk_sleep(sk), &wait);
341         release_sock(sk);
342         return timeo;
343 }
344 
345 
346 /*
347  * Copied from unix_stream_recvmsg, but removed credit checks,
348  * changed locking calls, changed address handling.
349  */
350 static int caif_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
351                                 struct msghdr *msg, size_t size,
352                                 int flags)
353 {
354         struct sock *sk = sock->sk;
355         int copied = 0;
356         int target;
357         int err = 0;
358         long timeo;
359 
360         err = -EOPNOTSUPP;
361         if (flags&MSG_OOB)
362                 goto out;
363 
364         msg->msg_namelen = 0;
365 
366         /*
367          * Lock the socket to prevent queue disordering
368          * while sleeps in memcpy_tomsg
369          */
370         err = -EAGAIN;
371         if (sk->sk_state == CAIF_CONNECTING)
372                 goto out;
373 
374         caif_read_lock(sk);
375         target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
376         timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT);
377 
378         do {
379                 int chunk;
380                 struct sk_buff *skb;
381 
382                 lock_sock(sk);
383                 skb = skb_dequeue(&sk->sk_receive_queue);
384                 caif_check_flow_release(sk);
385 
386                 if (skb == NULL) {
387                         if (copied >= target)
388                                 goto unlock;
389                         /*
390                          *      POSIX 1003.1g mandates this order.
391                          */
392                         err = sock_error(sk);
393                         if (err)
394                                 goto unlock;
395                         err = -ECONNRESET;
396                         if (sk->sk_shutdown & RCV_SHUTDOWN)
397                                 goto unlock;
398 
399                         err = -EPIPE;
400                         if (sk->sk_state != CAIF_CONNECTED)
401                                 goto unlock;
402                         if (sock_flag(sk, SOCK_DEAD))
403                                 goto unlock;
404 
405                         release_sock(sk);
406 
407                         err = -EAGAIN;
408                         if (!timeo)
409                                 break;
410 
411                         caif_read_unlock(sk);
412 
413                         timeo = caif_stream_data_wait(sk, timeo);
414 
415                         if (signal_pending(current)) {
416                                 err = sock_intr_errno(timeo);
417                                 goto out;
418                         }
419                         caif_read_lock(sk);
420                         continue;
421 unlock:
422                         release_sock(sk);
423                         break;
424                 }
425                 release_sock(sk);
426                 chunk = min_t(unsigned int, skb->len, size);
427                 if (memcpy_toiovec(msg->msg_iov, skb->data, chunk)) {
428                         skb_queue_head(&sk->sk_receive_queue, skb);
429                         if (copied == 0)
430                                 copied = -EFAULT;
431                         break;
432                 }
433                 copied += chunk;
434                 size -= chunk;
435 
436                 /* Mark read part of skb as used */
437                 if (!(flags & MSG_PEEK)) {
438                         skb_pull(skb, chunk);
439 
440                         /* put the skb back if we didn't use it up. */
441                         if (skb->len) {
442                                 skb_queue_head(&sk->sk_receive_queue, skb);
443                                 break;
444                         }
445                         kfree_skb(skb);
446 
447                 } else {
448                         /*
449                          * It is questionable, see note in unix_dgram_recvmsg.
450                          */
451                         /* put message back and return */
452                         skb_queue_head(&sk->sk_receive_queue, skb);
453                         break;
454                 }
455         } while (size);
456         caif_read_unlock(sk);
457 
458 out:
459         return copied ? : err;
460 }
461 
462 /*
463  * Copied from sock.c:sock_wait_for_wmem, but change to wait for
464  * CAIF flow-on and sock_writable.
465  */
466 static long caif_wait_for_flow_on(struct caifsock *cf_sk,
467                                 int wait_writeable, long timeo, int *err)
468 {
469         struct sock *sk = &cf_sk->sk;
470         DEFINE_WAIT(wait);
471         for (;;) {
472                 *err = 0;
473                 if (tx_flow_is_on(cf_sk) &&
474                         (!wait_writeable || sock_writeable(&cf_sk->sk)))
475                         break;
476                 *err = -ETIMEDOUT;
477                 if (!timeo)
478                         break;
479                 *err = -ERESTARTSYS;
480                 if (signal_pending(current))
481                         break;
482                 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
483                 *err = -ECONNRESET;
484                 if (sk->sk_shutdown & SHUTDOWN_MASK)
485                         break;
486                 *err = -sk->sk_err;
487                 if (sk->sk_err)
488                         break;
489                 *err = -EPIPE;
490                 if (cf_sk->sk.sk_state != CAIF_CONNECTED)
491                         break;
492                 timeo = schedule_timeout(timeo);
493         }
494         finish_wait(sk_sleep(sk), &wait);
495         return timeo;
496 }
497 
498 /*
499  * Transmit a SKB. The device may temporarily request re-transmission
500  * by returning EAGAIN.
501  */
502 static int transmit_skb(struct sk_buff *skb, struct caifsock *cf_sk,
503                         int noblock, long timeo)
504 {
505         struct cfpkt *pkt;
506 
507         pkt = cfpkt_fromnative(CAIF_DIR_OUT, skb);
508         memset(skb->cb, 0, sizeof(struct caif_payload_info));
509         cfpkt_set_prio(pkt, cf_sk->sk.sk_priority);
510 
511         if (cf_sk->layer.dn == NULL) {
512                 kfree_skb(skb);
513                 return -EINVAL;
514         }
515 
516         return cf_sk->layer.dn->transmit(cf_sk->layer.dn, pkt);
517 }
518 
519 /* Copied from af_unix:unix_dgram_sendmsg, and adapted to CAIF */
520 static int caif_seqpkt_sendmsg(struct kiocb *kiocb, struct socket *sock,
521                         struct msghdr *msg, size_t len)
522 {
523         struct sock *sk = sock->sk;
524         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
525         int buffer_size;
526         int ret = 0;
527         struct sk_buff *skb = NULL;
528         int noblock;
529         long timeo;
530         caif_assert(cf_sk);
531         ret = sock_error(sk);
532         if (ret)
533                 goto err;
534 
535         ret = -EOPNOTSUPP;
536         if (msg->msg_flags&MSG_OOB)
537                 goto err;
538 
539         ret = -EOPNOTSUPP;
540         if (msg->msg_namelen)
541                 goto err;
542 
543         ret = -EINVAL;
544         if (unlikely(msg->msg_iov->iov_base == NULL))
545                 goto err;
546         noblock = msg->msg_flags & MSG_DONTWAIT;
547 
548         timeo = sock_sndtimeo(sk, noblock);
549         timeo = caif_wait_for_flow_on(container_of(sk, struct caifsock, sk),
550                                 1, timeo, &ret);
551 
552         if (ret)
553                 goto err;
554         ret = -EPIPE;
555         if (cf_sk->sk.sk_state != CAIF_CONNECTED ||
556                 sock_flag(sk, SOCK_DEAD) ||
557                 (sk->sk_shutdown & RCV_SHUTDOWN))
558                 goto err;
559 
560         /* Error if trying to write more than maximum frame size. */
561         ret = -EMSGSIZE;
562         if (len > cf_sk->maxframe && cf_sk->sk.sk_protocol != CAIFPROTO_RFM)
563                 goto err;
564 
565         buffer_size = len + cf_sk->headroom + cf_sk->tailroom;
566 
567         ret = -ENOMEM;
568         skb = sock_alloc_send_skb(sk, buffer_size, noblock, &ret);
569 
570         if (!skb || skb_tailroom(skb) < buffer_size)
571                 goto err;
572 
573         skb_reserve(skb, cf_sk->headroom);
574 
575         ret = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
576 
577         if (ret)
578                 goto err;
579         ret = transmit_skb(skb, cf_sk, noblock, timeo);
580         if (ret < 0)
581                 /* skb is already freed */
582                 return ret;
583 
584         return len;
585 err:
586         kfree_skb(skb);
587         return ret;
588 }
589 
590 /*
591  * Copied from unix_stream_sendmsg and adapted to CAIF:
592  * Changed removed permission handling and added waiting for flow on
593  * and other minor adaptations.
594  */
595 static int caif_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
596                                 struct msghdr *msg, size_t len)
597 {
598         struct sock *sk = sock->sk;
599         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
600         int err, size;
601         struct sk_buff *skb;
602         int sent = 0;
603         long timeo;
604 
605         err = -EOPNOTSUPP;
606         if (unlikely(msg->msg_flags&MSG_OOB))
607                 goto out_err;
608 
609         if (unlikely(msg->msg_namelen))
610                 goto out_err;
611 
612         timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
613         timeo = caif_wait_for_flow_on(cf_sk, 1, timeo, &err);
614 
615         if (unlikely(sk->sk_shutdown & SEND_SHUTDOWN))
616                 goto pipe_err;
617 
618         while (sent < len) {
619 
620                 size = len-sent;
621 
622                 if (size > cf_sk->maxframe)
623                         size = cf_sk->maxframe;
624 
625                 /* If size is more than half of sndbuf, chop up message */
626                 if (size > ((sk->sk_sndbuf >> 1) - 64))
627                         size = (sk->sk_sndbuf >> 1) - 64;
628 
629                 if (size > SKB_MAX_ALLOC)
630                         size = SKB_MAX_ALLOC;
631 
632                 skb = sock_alloc_send_skb(sk,
633                                         size + cf_sk->headroom +
634                                         cf_sk->tailroom,
635                                         msg->msg_flags&MSG_DONTWAIT,
636                                         &err);
637                 if (skb == NULL)
638                         goto out_err;
639 
640                 skb_reserve(skb, cf_sk->headroom);
641                 /*
642                  *      If you pass two values to the sock_alloc_send_skb
643                  *      it tries to grab the large buffer with GFP_NOFS
644                  *      (which can fail easily), and if it fails grab the
645                  *      fallback size buffer which is under a page and will
646                  *      succeed. [Alan]
647                  */
648                 size = min_t(int, size, skb_tailroom(skb));
649 
650                 err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size);
651                 if (err) {
652                         kfree_skb(skb);
653                         goto out_err;
654                 }
655                 err = transmit_skb(skb, cf_sk,
656                                 msg->msg_flags&MSG_DONTWAIT, timeo);
657                 if (err < 0)
658                         /* skb is already freed */
659                         goto pipe_err;
660 
661                 sent += size;
662         }
663 
664         return sent;
665 
666 pipe_err:
667         if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
668                 send_sig(SIGPIPE, current, 0);
669         err = -EPIPE;
670 out_err:
671         return sent ? : err;
672 }
673 
674 static int setsockopt(struct socket *sock,
675                         int lvl, int opt, char __user *ov, unsigned int ol)
676 {
677         struct sock *sk = sock->sk;
678         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
679         int linksel;
680 
681         if (cf_sk->sk.sk_socket->state != SS_UNCONNECTED)
682                 return -ENOPROTOOPT;
683 
684         switch (opt) {
685         case CAIFSO_LINK_SELECT:
686                 if (ol < sizeof(int))
687                         return -EINVAL;
688                 if (lvl != SOL_CAIF)
689                         goto bad_sol;
690                 if (copy_from_user(&linksel, ov, sizeof(int)))
691                         return -EINVAL;
692                 lock_sock(&(cf_sk->sk));
693                 cf_sk->conn_req.link_selector = linksel;
694                 release_sock(&cf_sk->sk);
695                 return 0;
696 
697         case CAIFSO_REQ_PARAM:
698                 if (lvl != SOL_CAIF)
699                         goto bad_sol;
700                 if (cf_sk->sk.sk_protocol != CAIFPROTO_UTIL)
701                         return -ENOPROTOOPT;
702                 lock_sock(&(cf_sk->sk));
703                 if (ol > sizeof(cf_sk->conn_req.param.data) ||
704                         copy_from_user(&cf_sk->conn_req.param.data, ov, ol)) {
705                         release_sock(&cf_sk->sk);
706                         return -EINVAL;
707                 }
708                 cf_sk->conn_req.param.size = ol;
709                 release_sock(&cf_sk->sk);
710                 return 0;
711 
712         default:
713                 return -ENOPROTOOPT;
714         }
715 
716         return 0;
717 bad_sol:
718         return -ENOPROTOOPT;
719 
720 }
721 
722 /*
723  * caif_connect() - Connect a CAIF Socket
724  * Copied and modified af_irda.c:irda_connect().
725  *
726  * Note : by consulting "errno", the user space caller may learn the cause
727  * of the failure. Most of them are visible in the function, others may come
728  * from subroutines called and are listed here :
729  *  o -EAFNOSUPPORT: bad socket family or type.
730  *  o -ESOCKTNOSUPPORT: bad socket type or protocol
731  *  o -EINVAL: bad socket address, or CAIF link type
732  *  o -ECONNREFUSED: remote end refused the connection.
733  *  o -EINPROGRESS: connect request sent but timed out (or non-blocking)
734  *  o -EISCONN: already connected.
735  *  o -ETIMEDOUT: Connection timed out (send timeout)
736  *  o -ENODEV: No link layer to send request
737  *  o -ECONNRESET: Received Shutdown indication or lost link layer
738  *  o -ENOMEM: Out of memory
739  *
740  *  State Strategy:
741  *  o sk_state: holds the CAIF_* protocol state, it's updated by
742  *      caif_ctrl_cb.
743  *  o sock->state: holds the SS_* socket state and is updated by connect and
744  *      disconnect.
745  */
746 static int caif_connect(struct socket *sock, struct sockaddr *uaddr,
747                         int addr_len, int flags)
748 {
749         struct sock *sk = sock->sk;
750         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
751         long timeo;
752         int err;
753         int ifindex, headroom, tailroom;
754         unsigned int mtu;
755         struct net_device *dev;
756 
757         lock_sock(sk);
758 
759         err = -EAFNOSUPPORT;
760         if (uaddr->sa_family != AF_CAIF)
761                 goto out;
762 
763         switch (sock->state) {
764         case SS_UNCONNECTED:
765                 /* Normal case, a fresh connect */
766                 caif_assert(sk->sk_state == CAIF_DISCONNECTED);
767                 break;
768         case SS_CONNECTING:
769                 switch (sk->sk_state) {
770                 case CAIF_CONNECTED:
771                         sock->state = SS_CONNECTED;
772                         err = -EISCONN;
773                         goto out;
774                 case CAIF_DISCONNECTED:
775                         /* Reconnect allowed */
776                         break;
777                 case CAIF_CONNECTING:
778                         err = -EALREADY;
779                         if (flags & O_NONBLOCK)
780                                 goto out;
781                         goto wait_connect;
782                 }
783                 break;
784         case SS_CONNECTED:
785                 caif_assert(sk->sk_state == CAIF_CONNECTED ||
786                                 sk->sk_state == CAIF_DISCONNECTED);
787                 if (sk->sk_shutdown & SHUTDOWN_MASK) {
788                         /* Allow re-connect after SHUTDOWN_IND */
789                         caif_disconnect_client(sock_net(sk), &cf_sk->layer);
790                         caif_free_client(&cf_sk->layer);
791                         break;
792                 }
793                 /* No reconnect on a seqpacket socket */
794                 err = -EISCONN;
795                 goto out;
796         case SS_DISCONNECTING:
797         case SS_FREE:
798                 caif_assert(1); /*Should never happen */
799                 break;
800         }
801         sk->sk_state = CAIF_DISCONNECTED;
802         sock->state = SS_UNCONNECTED;
803         sk_stream_kill_queues(&cf_sk->sk);
804 
805         err = -EINVAL;
806         if (addr_len != sizeof(struct sockaddr_caif))
807                 goto out;
808 
809         memcpy(&cf_sk->conn_req.sockaddr, uaddr,
810                 sizeof(struct sockaddr_caif));
811 
812         /* Move to connecting socket, start sending Connect Requests */
813         sock->state = SS_CONNECTING;
814         sk->sk_state = CAIF_CONNECTING;
815 
816         /* Check priority value comming from socket */
817         /* if priority value is out of range it will be ajusted */
818         if (cf_sk->sk.sk_priority > CAIF_PRIO_MAX)
819                 cf_sk->conn_req.priority = CAIF_PRIO_MAX;
820         else if (cf_sk->sk.sk_priority < CAIF_PRIO_MIN)
821                 cf_sk->conn_req.priority = CAIF_PRIO_MIN;
822         else
823                 cf_sk->conn_req.priority = cf_sk->sk.sk_priority;
824 
825         /*ifindex = id of the interface.*/
826         cf_sk->conn_req.ifindex = cf_sk->sk.sk_bound_dev_if;
827 
828         cf_sk->layer.receive = caif_sktrecv_cb;
829 
830         err = caif_connect_client(sock_net(sk), &cf_sk->conn_req,
831                                 &cf_sk->layer, &ifindex, &headroom, &tailroom);
832 
833         if (err < 0) {
834                 cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
835                 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
836                 goto out;
837         }
838 
839         err = -ENODEV;
840         rcu_read_lock();
841         dev = dev_get_by_index_rcu(sock_net(sk), ifindex);
842         if (!dev) {
843                 rcu_read_unlock();
844                 goto out;
845         }
846         cf_sk->headroom = LL_RESERVED_SPACE_EXTRA(dev, headroom);
847         mtu = dev->mtu;
848         rcu_read_unlock();
849 
850         cf_sk->tailroom = tailroom;
851         cf_sk->maxframe = mtu - (headroom + tailroom);
852         if (cf_sk->maxframe < 1) {
853                 pr_warn("CAIF Interface MTU too small (%d)\n", dev->mtu);
854                 err = -ENODEV;
855                 goto out;
856         }
857 
858         err = -EINPROGRESS;
859 wait_connect:
860 
861         if (sk->sk_state != CAIF_CONNECTED && (flags & O_NONBLOCK))
862                 goto out;
863 
864         timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
865 
866         release_sock(sk);
867         err = -ERESTARTSYS;
868         timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
869                         sk->sk_state != CAIF_CONNECTING,
870                         timeo);
871         lock_sock(sk);
872         if (timeo < 0)
873                 goto out; /* -ERESTARTSYS */
874 
875         err = -ETIMEDOUT;
876         if (timeo == 0 && sk->sk_state != CAIF_CONNECTED)
877                 goto out;
878         if (sk->sk_state != CAIF_CONNECTED) {
879                 sock->state = SS_UNCONNECTED;
880                 err = sock_error(sk);
881                 if (!err)
882                         err = -ECONNREFUSED;
883                 goto out;
884         }
885         sock->state = SS_CONNECTED;
886         err = 0;
887 out:
888         release_sock(sk);
889         return err;
890 }
891 
892 /*
893  * caif_release() - Disconnect a CAIF Socket
894  * Copied and modified af_irda.c:irda_release().
895  */
896 static int caif_release(struct socket *sock)
897 {
898         struct sock *sk = sock->sk;
899         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
900 
901         if (!sk)
902                 return 0;
903 
904         set_tx_flow_off(cf_sk);
905 
906         /*
907          * Ensure that packets are not queued after this point in time.
908          * caif_queue_rcv_skb checks SOCK_DEAD holding the queue lock,
909          * this ensures no packets when sock is dead.
910          */
911         spin_lock_bh(&sk->sk_receive_queue.lock);
912         sock_set_flag(sk, SOCK_DEAD);
913         spin_unlock_bh(&sk->sk_receive_queue.lock);
914         sock->sk = NULL;
915 
916         WARN_ON(IS_ERR(cf_sk->debugfs_socket_dir));
917         if (cf_sk->debugfs_socket_dir != NULL)
918                 debugfs_remove_recursive(cf_sk->debugfs_socket_dir);
919 
920         lock_sock(&(cf_sk->sk));
921         sk->sk_state = CAIF_DISCONNECTED;
922         sk->sk_shutdown = SHUTDOWN_MASK;
923 
924         caif_disconnect_client(sock_net(sk), &cf_sk->layer);
925         cf_sk->sk.sk_socket->state = SS_DISCONNECTING;
926         wake_up_interruptible_poll(sk_sleep(sk), POLLERR|POLLHUP);
927 
928         sock_orphan(sk);
929         sk_stream_kill_queues(&cf_sk->sk);
930         release_sock(sk);
931         sock_put(sk);
932         return 0;
933 }
934 
935 /* Copied from af_unix.c:unix_poll(), added CAIF tx_flow handling */
936 static unsigned int caif_poll(struct file *file,
937                                 struct socket *sock, poll_table *wait)
938 {
939         struct sock *sk = sock->sk;
940         unsigned int mask;
941         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
942 
943         sock_poll_wait(file, sk_sleep(sk), wait);
944         mask = 0;
945 
946         /* exceptional events? */
947         if (sk->sk_err)
948                 mask |= POLLERR;
949         if (sk->sk_shutdown == SHUTDOWN_MASK)
950                 mask |= POLLHUP;
951         if (sk->sk_shutdown & RCV_SHUTDOWN)
952                 mask |= POLLRDHUP;
953 
954         /* readable? */
955         if (!skb_queue_empty(&sk->sk_receive_queue) ||
956                 (sk->sk_shutdown & RCV_SHUTDOWN))
957                 mask |= POLLIN | POLLRDNORM;
958 
959         /*
960          * we set writable also when the other side has shut down the
961          * connection. This prevents stuck sockets.
962          */
963         if (sock_writeable(sk) && tx_flow_is_on(cf_sk))
964                 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
965 
966         return mask;
967 }
968 
969 static const struct proto_ops caif_seqpacket_ops = {
970         .family = PF_CAIF,
971         .owner = THIS_MODULE,
972         .release = caif_release,
973         .bind = sock_no_bind,
974         .connect = caif_connect,
975         .socketpair = sock_no_socketpair,
976         .accept = sock_no_accept,
977         .getname = sock_no_getname,
978         .poll = caif_poll,
979         .ioctl = sock_no_ioctl,
980         .listen = sock_no_listen,
981         .shutdown = sock_no_shutdown,
982         .setsockopt = setsockopt,
983         .getsockopt = sock_no_getsockopt,
984         .sendmsg = caif_seqpkt_sendmsg,
985         .recvmsg = caif_seqpkt_recvmsg,
986         .mmap = sock_no_mmap,
987         .sendpage = sock_no_sendpage,
988 };
989 
990 static const struct proto_ops caif_stream_ops = {
991         .family = PF_CAIF,
992         .owner = THIS_MODULE,
993         .release = caif_release,
994         .bind = sock_no_bind,
995         .connect = caif_connect,
996         .socketpair = sock_no_socketpair,
997         .accept = sock_no_accept,
998         .getname = sock_no_getname,
999         .poll = caif_poll,
1000         .ioctl = sock_no_ioctl,
1001         .listen = sock_no_listen,
1002         .shutdown = sock_no_shutdown,
1003         .setsockopt = setsockopt,
1004         .getsockopt = sock_no_getsockopt,
1005         .sendmsg = caif_stream_sendmsg,
1006         .recvmsg = caif_stream_recvmsg,
1007         .mmap = sock_no_mmap,
1008         .sendpage = sock_no_sendpage,
1009 };
1010 
1011 /* This function is called when a socket is finally destroyed. */
1012 static void caif_sock_destructor(struct sock *sk)
1013 {
1014         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
1015         caif_assert(!atomic_read(&sk->sk_wmem_alloc));
1016         caif_assert(sk_unhashed(sk));
1017         caif_assert(!sk->sk_socket);
1018         if (!sock_flag(sk, SOCK_DEAD)) {
1019                 pr_debug("Attempt to release alive CAIF socket: %p\n", sk);
1020                 return;
1021         }
1022         sk_stream_kill_queues(&cf_sk->sk);
1023         caif_free_client(&cf_sk->layer);
1024 }
1025 
1026 static int caif_create(struct net *net, struct socket *sock, int protocol,
1027                         int kern)
1028 {
1029         struct sock *sk = NULL;
1030         struct caifsock *cf_sk = NULL;
1031         static struct proto prot = {.name = "PF_CAIF",
1032                 .owner = THIS_MODULE,
1033                 .obj_size = sizeof(struct caifsock),
1034         };
1035 
1036         if (!capable(CAP_SYS_ADMIN) && !capable(CAP_NET_ADMIN))
1037                 return -EPERM;
1038         /*
1039          * The sock->type specifies the socket type to use.
1040          * The CAIF socket is a packet stream in the sense
1041          * that it is packet based. CAIF trusts the reliability
1042          * of the link, no resending is implemented.
1043          */
1044         if (sock->type == SOCK_SEQPACKET)
1045                 sock->ops = &caif_seqpacket_ops;
1046         else if (sock->type == SOCK_STREAM)
1047                 sock->ops = &caif_stream_ops;
1048         else
1049                 return -ESOCKTNOSUPPORT;
1050 
1051         if (protocol < 0 || protocol >= CAIFPROTO_MAX)
1052                 return -EPROTONOSUPPORT;
1053         /*
1054          * Set the socket state to unconnected.  The socket state
1055          * is really not used at all in the net/core or socket.c but the
1056          * initialization makes sure that sock->state is not uninitialized.
1057          */
1058         sk = sk_alloc(net, PF_CAIF, GFP_KERNEL, &prot);
1059         if (!sk)
1060                 return -ENOMEM;
1061 
1062         cf_sk = container_of(sk, struct caifsock, sk);
1063 
1064         /* Store the protocol */
1065         sk->sk_protocol = (unsigned char) protocol;
1066 
1067         /* Initialize default priority for well-known cases */
1068         switch (protocol) {
1069         case CAIFPROTO_AT:
1070                 sk->sk_priority = TC_PRIO_CONTROL;
1071                 break;
1072         case CAIFPROTO_RFM:
1073                 sk->sk_priority = TC_PRIO_INTERACTIVE_BULK;
1074                 break;
1075         default:
1076                 sk->sk_priority = TC_PRIO_BESTEFFORT;
1077         }
1078 
1079         /*
1080          * Lock in order to try to stop someone from opening the socket
1081          * too early.
1082          */
1083         lock_sock(&(cf_sk->sk));
1084 
1085         /* Initialize the nozero default sock structure data. */
1086         sock_init_data(sock, sk);
1087         sk->sk_destruct = caif_sock_destructor;
1088 
1089         mutex_init(&cf_sk->readlock); /* single task reading lock */
1090         cf_sk->layer.ctrlcmd = caif_ctrl_cb;
1091         cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
1092         cf_sk->sk.sk_state = CAIF_DISCONNECTED;
1093 
1094         set_tx_flow_off(cf_sk);
1095         set_rx_flow_on(cf_sk);
1096 
1097         /* Set default options on configuration */
1098         cf_sk->conn_req.link_selector = CAIF_LINK_LOW_LATENCY;
1099         cf_sk->conn_req.protocol = protocol;
1100         release_sock(&cf_sk->sk);
1101         return 0;
1102 }
1103 
1104 
1105 static struct net_proto_family caif_family_ops = {
1106         .family = PF_CAIF,
1107         .create = caif_create,
1108         .owner = THIS_MODULE,
1109 };
1110 
1111 static int __init caif_sktinit_module(void)
1112 {
1113         int err = sock_register(&caif_family_ops);
1114         if (!err)
1115                 return err;
1116         return 0;
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);
1125 

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