Version:  2.0.40 2.2.26 2.4.37 2.6.39 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15

Linux/net/caif/caif_socket.c

  1 /*
  2  * Copyright (C) ST-Ericsson AB 2010
  3  * Author:      Sjur Brendeland
  4  * License terms: GNU General Public License (GPL) version 2
  5  */
  6 
  7 #define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
  8 
  9 #include <linux/fs.h>
 10 #include <linux/init.h>
 11 #include <linux/module.h>
 12 #include <linux/sched.h>
 13 #include <linux/spinlock.h>
 14 #include <linux/mutex.h>
 15 #include <linux/list.h>
 16 #include <linux/wait.h>
 17 #include <linux/poll.h>
 18 #include <linux/tcp.h>
 19 #include <linux/uaccess.h>
 20 #include <linux/debugfs.h>
 21 #include <linux/caif/caif_socket.h>
 22 #include <linux/pkt_sched.h>
 23 #include <net/sock.h>
 24 #include <net/tcp_states.h>
 25 #include <net/caif/caif_layer.h>
 26 #include <net/caif/caif_dev.h>
 27 #include <net/caif/cfpkt.h>
 28 
 29 MODULE_LICENSE("GPL");
 30 MODULE_ALIAS_NETPROTO(AF_CAIF);
 31 
 32 /*
 33  * CAIF state is re-using the TCP socket states.
 34  * caif_states stored in sk_state reflect the state as reported by
 35  * the CAIF stack, while sk_socket->state is the state of the socket.
 36  */
 37 enum caif_states {
 38         CAIF_CONNECTED          = TCP_ESTABLISHED,
 39         CAIF_CONNECTING = TCP_SYN_SENT,
 40         CAIF_DISCONNECTED       = TCP_CLOSE
 41 };
 42 
 43 #define TX_FLOW_ON_BIT  1
 44 #define RX_FLOW_ON_BIT  2
 45 
 46 struct caifsock {
 47         struct sock sk; /* must be first member */
 48         struct cflayer layer;
 49         u32 flow_state;
 50         struct caif_connect_request conn_req;
 51         struct mutex readlock;
 52         struct dentry *debugfs_socket_dir;
 53         int headroom, tailroom, maxframe;
 54 };
 55 
 56 static int rx_flow_is_on(struct caifsock *cf_sk)
 57 {
 58         return test_bit(RX_FLOW_ON_BIT,
 59                         (void *) &cf_sk->flow_state);
 60 }
 61 
 62 static int tx_flow_is_on(struct caifsock *cf_sk)
 63 {
 64         return test_bit(TX_FLOW_ON_BIT,
 65                         (void *) &cf_sk->flow_state);
 66 }
 67 
 68 static void set_rx_flow_off(struct caifsock *cf_sk)
 69 {
 70          clear_bit(RX_FLOW_ON_BIT,
 71                  (void *) &cf_sk->flow_state);
 72 }
 73 
 74 static void set_rx_flow_on(struct caifsock *cf_sk)
 75 {
 76          set_bit(RX_FLOW_ON_BIT,
 77                         (void *) &cf_sk->flow_state);
 78 }
 79 
 80 static void set_tx_flow_off(struct caifsock *cf_sk)
 81 {
 82          clear_bit(TX_FLOW_ON_BIT,
 83                 (void *) &cf_sk->flow_state);
 84 }
 85 
 86 static void set_tx_flow_on(struct caifsock *cf_sk)
 87 {
 88          set_bit(TX_FLOW_ON_BIT,
 89                 (void *) &cf_sk->flow_state);
 90 }
 91 
 92 static void caif_read_lock(struct sock *sk)
 93 {
 94         struct caifsock *cf_sk;
 95         cf_sk = container_of(sk, struct caifsock, sk);
 96         mutex_lock(&cf_sk->readlock);
 97 }
 98 
 99 static void caif_read_unlock(struct sock *sk)
100 {
101         struct caifsock *cf_sk;
102         cf_sk = container_of(sk, struct caifsock, sk);
103         mutex_unlock(&cf_sk->readlock);
104 }
105 
106 static int sk_rcvbuf_lowwater(struct caifsock *cf_sk)
107 {
108         /* A quarter of full buffer is used a low water mark */
109         return cf_sk->sk.sk_rcvbuf / 4;
110 }
111 
112 static void caif_flow_ctrl(struct sock *sk, int mode)
113 {
114         struct caifsock *cf_sk;
115         cf_sk = container_of(sk, struct caifsock, sk);
116         if (cf_sk->layer.dn && cf_sk->layer.dn->modemcmd)
117                 cf_sk->layer.dn->modemcmd(cf_sk->layer.dn, mode);
118 }
119 
120 /*
121  * Copied from sock.c:sock_queue_rcv_skb(), but changed so packets are
122  * not dropped, but CAIF is sending flow off instead.
123  */
124 static int caif_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
125 {
126         int err;
127         unsigned long flags;
128         struct sk_buff_head *list = &sk->sk_receive_queue;
129         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
130 
131         if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
132                 (unsigned int)sk->sk_rcvbuf && rx_flow_is_on(cf_sk)) {
133                 net_dbg_ratelimited("sending flow OFF (queue len = %d %d)\n",
134                                     atomic_read(&cf_sk->sk.sk_rmem_alloc),
135                                     sk_rcvbuf_lowwater(cf_sk));
136                 set_rx_flow_off(cf_sk);
137                 caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ);
138         }
139 
140         err = sk_filter(sk, skb);
141         if (err)
142                 return err;
143         if (!sk_rmem_schedule(sk, skb, skb->truesize) && rx_flow_is_on(cf_sk)) {
144                 set_rx_flow_off(cf_sk);
145                 net_dbg_ratelimited("sending flow OFF due to rmem_schedule\n");
146                 caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ);
147         }
148         skb->dev = NULL;
149         skb_set_owner_r(skb, sk);
150         /* Cache the SKB length before we tack it onto the receive
151          * queue. Once it is added it no longer belongs to us and
152          * may be freed by other threads of control pulling packets
153          * from the queue.
154          */
155         spin_lock_irqsave(&list->lock, flags);
156         if (!sock_flag(sk, SOCK_DEAD))
157                 __skb_queue_tail(list, skb);
158         spin_unlock_irqrestore(&list->lock, flags);
159 
160         if (!sock_flag(sk, SOCK_DEAD))
161                 sk->sk_data_ready(sk);
162         else
163                 kfree_skb(skb);
164         return 0;
165 }
166 
167 /* Packet Receive Callback function called from CAIF Stack */
168 static int caif_sktrecv_cb(struct cflayer *layr, struct cfpkt *pkt)
169 {
170         struct caifsock *cf_sk;
171         struct sk_buff *skb;
172 
173         cf_sk = container_of(layr, struct caifsock, layer);
174         skb = cfpkt_tonative(pkt);
175 
176         if (unlikely(cf_sk->sk.sk_state != CAIF_CONNECTED)) {
177                 kfree_skb(skb);
178                 return 0;
179         }
180         caif_queue_rcv_skb(&cf_sk->sk, skb);
181         return 0;
182 }
183 
184 static void cfsk_hold(struct cflayer *layr)
185 {
186         struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
187         sock_hold(&cf_sk->sk);
188 }
189 
190 static void cfsk_put(struct cflayer *layr)
191 {
192         struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
193         sock_put(&cf_sk->sk);
194 }
195 
196 /* Packet Control Callback function called from CAIF */
197 static void caif_ctrl_cb(struct cflayer *layr,
198                          enum caif_ctrlcmd flow,
199                          int phyid)
200 {
201         struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
202         switch (flow) {
203         case CAIF_CTRLCMD_FLOW_ON_IND:
204                 /* OK from modem to start sending again */
205                 set_tx_flow_on(cf_sk);
206                 cf_sk->sk.sk_state_change(&cf_sk->sk);
207                 break;
208 
209         case CAIF_CTRLCMD_FLOW_OFF_IND:
210                 /* Modem asks us to shut up */
211                 set_tx_flow_off(cf_sk);
212                 cf_sk->sk.sk_state_change(&cf_sk->sk);
213                 break;
214 
215         case CAIF_CTRLCMD_INIT_RSP:
216                 /* We're now connected */
217                 caif_client_register_refcnt(&cf_sk->layer,
218                                                 cfsk_hold, cfsk_put);
219                 cf_sk->sk.sk_state = CAIF_CONNECTED;
220                 set_tx_flow_on(cf_sk);
221                 cf_sk->sk.sk_shutdown = 0;
222                 cf_sk->sk.sk_state_change(&cf_sk->sk);
223                 break;
224 
225         case CAIF_CTRLCMD_DEINIT_RSP:
226                 /* We're now disconnected */
227                 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
228                 cf_sk->sk.sk_state_change(&cf_sk->sk);
229                 break;
230 
231         case CAIF_CTRLCMD_INIT_FAIL_RSP:
232                 /* Connect request failed */
233                 cf_sk->sk.sk_err = ECONNREFUSED;
234                 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
235                 cf_sk->sk.sk_shutdown = SHUTDOWN_MASK;
236                 /*
237                  * Socket "standards" seems to require POLLOUT to
238                  * be set at connect failure.
239                  */
240                 set_tx_flow_on(cf_sk);
241                 cf_sk->sk.sk_state_change(&cf_sk->sk);
242                 break;
243 
244         case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
245                 /* Modem has closed this connection, or device is down. */
246                 cf_sk->sk.sk_shutdown = SHUTDOWN_MASK;
247                 cf_sk->sk.sk_err = ECONNRESET;
248                 set_rx_flow_on(cf_sk);
249                 cf_sk->sk.sk_error_report(&cf_sk->sk);
250                 break;
251 
252         default:
253                 pr_debug("Unexpected flow command %d\n", flow);
254         }
255 }
256 
257 static void caif_check_flow_release(struct sock *sk)
258 {
259         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
260 
261         if (rx_flow_is_on(cf_sk))
262                 return;
263 
264         if (atomic_read(&sk->sk_rmem_alloc) <= sk_rcvbuf_lowwater(cf_sk)) {
265                         set_rx_flow_on(cf_sk);
266                         caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_ON_REQ);
267         }
268 }
269 
270 /*
271  * Copied from unix_dgram_recvmsg, but removed credit checks,
272  * changed locking, address handling and added MSG_TRUNC.
273  */
274 static int caif_seqpkt_recvmsg(struct kiocb *iocb, struct socket *sock,
275                                struct msghdr *m, size_t len, int flags)
276 
277 {
278         struct sock *sk = sock->sk;
279         struct sk_buff *skb;
280         int ret;
281         int copylen;
282 
283         ret = -EOPNOTSUPP;
284         if (m->msg_flags&MSG_OOB)
285                 goto read_error;
286 
287         skb = skb_recv_datagram(sk, flags, 0 , &ret);
288         if (!skb)
289                 goto read_error;
290         copylen = skb->len;
291         if (len < copylen) {
292                 m->msg_flags |= MSG_TRUNC;
293                 copylen = len;
294         }
295 
296         ret = skb_copy_datagram_iovec(skb, 0, m->msg_iov, copylen);
297         if (ret)
298                 goto out_free;
299 
300         ret = (flags & MSG_TRUNC) ? skb->len : copylen;
301 out_free:
302         skb_free_datagram(sk, skb);
303         caif_check_flow_release(sk);
304         return ret;
305 
306 read_error:
307         return ret;
308 }
309 
310 
311 /* Copied from unix_stream_wait_data, identical except for lock call. */
312 static long caif_stream_data_wait(struct sock *sk, long timeo)
313 {
314         DEFINE_WAIT(wait);
315         lock_sock(sk);
316 
317         for (;;) {
318                 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
319 
320                 if (!skb_queue_empty(&sk->sk_receive_queue) ||
321                         sk->sk_err ||
322                         sk->sk_state != CAIF_CONNECTED ||
323                         sock_flag(sk, SOCK_DEAD) ||
324                         (sk->sk_shutdown & RCV_SHUTDOWN) ||
325                         signal_pending(current) ||
326                         !timeo)
327                         break;
328 
329                 set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
330                 release_sock(sk);
331                 timeo = schedule_timeout(timeo);
332                 lock_sock(sk);
333                 clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
334         }
335 
336         finish_wait(sk_sleep(sk), &wait);
337         release_sock(sk);
338         return timeo;
339 }
340 
341 
342 /*
343  * Copied from unix_stream_recvmsg, but removed credit checks,
344  * changed locking calls, changed address handling.
345  */
346 static int caif_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
347                                struct msghdr *msg, size_t size,
348                                int flags)
349 {
350         struct sock *sk = sock->sk;
351         int copied = 0;
352         int target;
353         int err = 0;
354         long timeo;
355 
356         err = -EOPNOTSUPP;
357         if (flags&MSG_OOB)
358                 goto out;
359 
360         /*
361          * Lock the socket to prevent queue disordering
362          * while sleeps in memcpy_tomsg
363          */
364         err = -EAGAIN;
365         if (sk->sk_state == CAIF_CONNECTING)
366                 goto out;
367 
368         caif_read_lock(sk);
369         target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
370         timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT);
371 
372         do {
373                 int chunk;
374                 struct sk_buff *skb;
375 
376                 lock_sock(sk);
377                 skb = skb_dequeue(&sk->sk_receive_queue);
378                 caif_check_flow_release(sk);
379 
380                 if (skb == NULL) {
381                         if (copied >= target)
382                                 goto unlock;
383                         /*
384                          *      POSIX 1003.1g mandates this order.
385                          */
386                         err = sock_error(sk);
387                         if (err)
388                                 goto unlock;
389                         err = -ECONNRESET;
390                         if (sk->sk_shutdown & RCV_SHUTDOWN)
391                                 goto unlock;
392 
393                         err = -EPIPE;
394                         if (sk->sk_state != CAIF_CONNECTED)
395                                 goto unlock;
396                         if (sock_flag(sk, SOCK_DEAD))
397                                 goto unlock;
398 
399                         release_sock(sk);
400 
401                         err = -EAGAIN;
402                         if (!timeo)
403                                 break;
404 
405                         caif_read_unlock(sk);
406 
407                         timeo = caif_stream_data_wait(sk, timeo);
408 
409                         if (signal_pending(current)) {
410                                 err = sock_intr_errno(timeo);
411                                 goto out;
412                         }
413                         caif_read_lock(sk);
414                         continue;
415 unlock:
416                         release_sock(sk);
417                         break;
418                 }
419                 release_sock(sk);
420                 chunk = min_t(unsigned int, skb->len, size);
421                 if (memcpy_toiovec(msg->msg_iov, skb->data, chunk)) {
422                         skb_queue_head(&sk->sk_receive_queue, skb);
423                         if (copied == 0)
424                                 copied = -EFAULT;
425                         break;
426                 }
427                 copied += chunk;
428                 size -= chunk;
429 
430                 /* Mark read part of skb as used */
431                 if (!(flags & MSG_PEEK)) {
432                         skb_pull(skb, chunk);
433 
434                         /* put the skb back if we didn't use it up. */
435                         if (skb->len) {
436                                 skb_queue_head(&sk->sk_receive_queue, skb);
437                                 break;
438                         }
439                         kfree_skb(skb);
440 
441                 } else {
442                         /*
443                          * It is questionable, see note in unix_dgram_recvmsg.
444                          */
445                         /* put message back and return */
446                         skb_queue_head(&sk->sk_receive_queue, skb);
447                         break;
448                 }
449         } while (size);
450         caif_read_unlock(sk);
451 
452 out:
453         return copied ? : err;
454 }
455 
456 /*
457  * Copied from sock.c:sock_wait_for_wmem, but change to wait for
458  * CAIF flow-on and sock_writable.
459  */
460 static long caif_wait_for_flow_on(struct caifsock *cf_sk,
461                                   int wait_writeable, long timeo, int *err)
462 {
463         struct sock *sk = &cf_sk->sk;
464         DEFINE_WAIT(wait);
465         for (;;) {
466                 *err = 0;
467                 if (tx_flow_is_on(cf_sk) &&
468                         (!wait_writeable || sock_writeable(&cf_sk->sk)))
469                         break;
470                 *err = -ETIMEDOUT;
471                 if (!timeo)
472                         break;
473                 *err = -ERESTARTSYS;
474                 if (signal_pending(current))
475                         break;
476                 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
477                 *err = -ECONNRESET;
478                 if (sk->sk_shutdown & SHUTDOWN_MASK)
479                         break;
480                 *err = -sk->sk_err;
481                 if (sk->sk_err)
482                         break;
483                 *err = -EPIPE;
484                 if (cf_sk->sk.sk_state != CAIF_CONNECTED)
485                         break;
486                 timeo = schedule_timeout(timeo);
487         }
488         finish_wait(sk_sleep(sk), &wait);
489         return timeo;
490 }
491 
492 /*
493  * Transmit a SKB. The device may temporarily request re-transmission
494  * by returning EAGAIN.
495  */
496 static int transmit_skb(struct sk_buff *skb, struct caifsock *cf_sk,
497                         int noblock, long timeo)
498 {
499         struct cfpkt *pkt;
500 
501         pkt = cfpkt_fromnative(CAIF_DIR_OUT, skb);
502         memset(skb->cb, 0, sizeof(struct caif_payload_info));
503         cfpkt_set_prio(pkt, cf_sk->sk.sk_priority);
504 
505         if (cf_sk->layer.dn == NULL) {
506                 kfree_skb(skb);
507                 return -EINVAL;
508         }
509 
510         return cf_sk->layer.dn->transmit(cf_sk->layer.dn, pkt);
511 }
512 
513 /* Copied from af_unix:unix_dgram_sendmsg, and adapted to CAIF */
514 static int caif_seqpkt_sendmsg(struct kiocb *kiocb, struct socket *sock,
515                                struct msghdr *msg, size_t len)
516 {
517         struct sock *sk = sock->sk;
518         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
519         int buffer_size;
520         int ret = 0;
521         struct sk_buff *skb = NULL;
522         int noblock;
523         long timeo;
524         caif_assert(cf_sk);
525         ret = sock_error(sk);
526         if (ret)
527                 goto err;
528 
529         ret = -EOPNOTSUPP;
530         if (msg->msg_flags&MSG_OOB)
531                 goto err;
532 
533         ret = -EOPNOTSUPP;
534         if (msg->msg_namelen)
535                 goto err;
536 
537         ret = -EINVAL;
538         if (unlikely(msg->msg_iov->iov_base == NULL))
539                 goto err;
540         noblock = msg->msg_flags & MSG_DONTWAIT;
541 
542         timeo = sock_sndtimeo(sk, noblock);
543         timeo = caif_wait_for_flow_on(container_of(sk, struct caifsock, sk),
544                                 1, timeo, &ret);
545 
546         if (ret)
547                 goto err;
548         ret = -EPIPE;
549         if (cf_sk->sk.sk_state != CAIF_CONNECTED ||
550                 sock_flag(sk, SOCK_DEAD) ||
551                 (sk->sk_shutdown & RCV_SHUTDOWN))
552                 goto err;
553 
554         /* Error if trying to write more than maximum frame size. */
555         ret = -EMSGSIZE;
556         if (len > cf_sk->maxframe && cf_sk->sk.sk_protocol != CAIFPROTO_RFM)
557                 goto err;
558 
559         buffer_size = len + cf_sk->headroom + cf_sk->tailroom;
560 
561         ret = -ENOMEM;
562         skb = sock_alloc_send_skb(sk, buffer_size, noblock, &ret);
563 
564         if (!skb || skb_tailroom(skb) < buffer_size)
565                 goto err;
566 
567         skb_reserve(skb, cf_sk->headroom);
568 
569         ret = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
570 
571         if (ret)
572                 goto err;
573         ret = transmit_skb(skb, cf_sk, noblock, timeo);
574         if (ret < 0)
575                 /* skb is already freed */
576                 return ret;
577 
578         return len;
579 err:
580         kfree_skb(skb);
581         return ret;
582 }
583 
584 /*
585  * Copied from unix_stream_sendmsg and adapted to CAIF:
586  * Changed removed permission handling and added waiting for flow on
587  * and other minor adaptations.
588  */
589 static int caif_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
590                                struct msghdr *msg, size_t len)
591 {
592         struct sock *sk = sock->sk;
593         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
594         int err, size;
595         struct sk_buff *skb;
596         int sent = 0;
597         long timeo;
598 
599         err = -EOPNOTSUPP;
600         if (unlikely(msg->msg_flags&MSG_OOB))
601                 goto out_err;
602 
603         if (unlikely(msg->msg_namelen))
604                 goto out_err;
605 
606         timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
607         timeo = caif_wait_for_flow_on(cf_sk, 1, timeo, &err);
608 
609         if (unlikely(sk->sk_shutdown & SEND_SHUTDOWN))
610                 goto pipe_err;
611 
612         while (sent < len) {
613 
614                 size = len-sent;
615 
616                 if (size > cf_sk->maxframe)
617                         size = cf_sk->maxframe;
618 
619                 /* If size is more than half of sndbuf, chop up message */
620                 if (size > ((sk->sk_sndbuf >> 1) - 64))
621                         size = (sk->sk_sndbuf >> 1) - 64;
622 
623                 if (size > SKB_MAX_ALLOC)
624                         size = SKB_MAX_ALLOC;
625 
626                 skb = sock_alloc_send_skb(sk,
627                                         size + cf_sk->headroom +
628                                         cf_sk->tailroom,
629                                         msg->msg_flags&MSG_DONTWAIT,
630                                         &err);
631                 if (skb == NULL)
632                         goto out_err;
633 
634                 skb_reserve(skb, cf_sk->headroom);
635                 /*
636                  *      If you pass two values to the sock_alloc_send_skb
637                  *      it tries to grab the large buffer with GFP_NOFS
638                  *      (which can fail easily), and if it fails grab the
639                  *      fallback size buffer which is under a page and will
640                  *      succeed. [Alan]
641                  */
642                 size = min_t(int, size, skb_tailroom(skb));
643 
644                 err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size);
645                 if (err) {
646                         kfree_skb(skb);
647                         goto out_err;
648                 }
649                 err = transmit_skb(skb, cf_sk,
650                                 msg->msg_flags&MSG_DONTWAIT, timeo);
651                 if (err < 0)
652                         /* skb is already freed */
653                         goto pipe_err;
654 
655                 sent += size;
656         }
657 
658         return sent;
659 
660 pipe_err:
661         if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
662                 send_sig(SIGPIPE, current, 0);
663         err = -EPIPE;
664 out_err:
665         return sent ? : err;
666 }
667 
668 static int setsockopt(struct socket *sock,
669                       int lvl, int opt, char __user *ov, unsigned int ol)
670 {
671         struct sock *sk = sock->sk;
672         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
673         int linksel;
674 
675         if (cf_sk->sk.sk_socket->state != SS_UNCONNECTED)
676                 return -ENOPROTOOPT;
677 
678         switch (opt) {
679         case CAIFSO_LINK_SELECT:
680                 if (ol < sizeof(int))
681                         return -EINVAL;
682                 if (lvl != SOL_CAIF)
683                         goto bad_sol;
684                 if (copy_from_user(&linksel, ov, sizeof(int)))
685                         return -EINVAL;
686                 lock_sock(&(cf_sk->sk));
687                 cf_sk->conn_req.link_selector = linksel;
688                 release_sock(&cf_sk->sk);
689                 return 0;
690 
691         case CAIFSO_REQ_PARAM:
692                 if (lvl != SOL_CAIF)
693                         goto bad_sol;
694                 if (cf_sk->sk.sk_protocol != CAIFPROTO_UTIL)
695                         return -ENOPROTOOPT;
696                 lock_sock(&(cf_sk->sk));
697                 if (ol > sizeof(cf_sk->conn_req.param.data) ||
698                         copy_from_user(&cf_sk->conn_req.param.data, ov, ol)) {
699                         release_sock(&cf_sk->sk);
700                         return -EINVAL;
701                 }
702                 cf_sk->conn_req.param.size = ol;
703                 release_sock(&cf_sk->sk);
704                 return 0;
705 
706         default:
707                 return -ENOPROTOOPT;
708         }
709 
710         return 0;
711 bad_sol:
712         return -ENOPROTOOPT;
713 
714 }
715 
716 /*
717  * caif_connect() - Connect a CAIF Socket
718  * Copied and modified af_irda.c:irda_connect().
719  *
720  * Note : by consulting "errno", the user space caller may learn the cause
721  * of the failure. Most of them are visible in the function, others may come
722  * from subroutines called and are listed here :
723  *  o -EAFNOSUPPORT: bad socket family or type.
724  *  o -ESOCKTNOSUPPORT: bad socket type or protocol
725  *  o -EINVAL: bad socket address, or CAIF link type
726  *  o -ECONNREFUSED: remote end refused the connection.
727  *  o -EINPROGRESS: connect request sent but timed out (or non-blocking)
728  *  o -EISCONN: already connected.
729  *  o -ETIMEDOUT: Connection timed out (send timeout)
730  *  o -ENODEV: No link layer to send request
731  *  o -ECONNRESET: Received Shutdown indication or lost link layer
732  *  o -ENOMEM: Out of memory
733  *
734  *  State Strategy:
735  *  o sk_state: holds the CAIF_* protocol state, it's updated by
736  *      caif_ctrl_cb.
737  *  o sock->state: holds the SS_* socket state and is updated by connect and
738  *      disconnect.
739  */
740 static int caif_connect(struct socket *sock, struct sockaddr *uaddr,
741                         int addr_len, int flags)
742 {
743         struct sock *sk = sock->sk;
744         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
745         long timeo;
746         int err;
747         int ifindex, headroom, tailroom;
748         unsigned int mtu;
749         struct net_device *dev;
750 
751         lock_sock(sk);
752 
753         err = -EAFNOSUPPORT;
754         if (uaddr->sa_family != AF_CAIF)
755                 goto out;
756 
757         switch (sock->state) {
758         case SS_UNCONNECTED:
759                 /* Normal case, a fresh connect */
760                 caif_assert(sk->sk_state == CAIF_DISCONNECTED);
761                 break;
762         case SS_CONNECTING:
763                 switch (sk->sk_state) {
764                 case CAIF_CONNECTED:
765                         sock->state = SS_CONNECTED;
766                         err = -EISCONN;
767                         goto out;
768                 case CAIF_DISCONNECTED:
769                         /* Reconnect allowed */
770                         break;
771                 case CAIF_CONNECTING:
772                         err = -EALREADY;
773                         if (flags & O_NONBLOCK)
774                                 goto out;
775                         goto wait_connect;
776                 }
777                 break;
778         case SS_CONNECTED:
779                 caif_assert(sk->sk_state == CAIF_CONNECTED ||
780                                 sk->sk_state == CAIF_DISCONNECTED);
781                 if (sk->sk_shutdown & SHUTDOWN_MASK) {
782                         /* Allow re-connect after SHUTDOWN_IND */
783                         caif_disconnect_client(sock_net(sk), &cf_sk->layer);
784                         caif_free_client(&cf_sk->layer);
785                         break;
786                 }
787                 /* No reconnect on a seqpacket socket */
788                 err = -EISCONN;
789                 goto out;
790         case SS_DISCONNECTING:
791         case SS_FREE:
792                 caif_assert(1); /*Should never happen */
793                 break;
794         }
795         sk->sk_state = CAIF_DISCONNECTED;
796         sock->state = SS_UNCONNECTED;
797         sk_stream_kill_queues(&cf_sk->sk);
798 
799         err = -EINVAL;
800         if (addr_len != sizeof(struct sockaddr_caif))
801                 goto out;
802 
803         memcpy(&cf_sk->conn_req.sockaddr, uaddr,
804                 sizeof(struct sockaddr_caif));
805 
806         /* Move to connecting socket, start sending Connect Requests */
807         sock->state = SS_CONNECTING;
808         sk->sk_state = CAIF_CONNECTING;
809 
810         /* Check priority value comming from socket */
811         /* if priority value is out of range it will be ajusted */
812         if (cf_sk->sk.sk_priority > CAIF_PRIO_MAX)
813                 cf_sk->conn_req.priority = CAIF_PRIO_MAX;
814         else if (cf_sk->sk.sk_priority < CAIF_PRIO_MIN)
815                 cf_sk->conn_req.priority = CAIF_PRIO_MIN;
816         else
817                 cf_sk->conn_req.priority = cf_sk->sk.sk_priority;
818 
819         /*ifindex = id of the interface.*/
820         cf_sk->conn_req.ifindex = cf_sk->sk.sk_bound_dev_if;
821 
822         cf_sk->layer.receive = caif_sktrecv_cb;
823 
824         err = caif_connect_client(sock_net(sk), &cf_sk->conn_req,
825                                 &cf_sk->layer, &ifindex, &headroom, &tailroom);
826 
827         if (err < 0) {
828                 cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
829                 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
830                 goto out;
831         }
832 
833         err = -ENODEV;
834         rcu_read_lock();
835         dev = dev_get_by_index_rcu(sock_net(sk), ifindex);
836         if (!dev) {
837                 rcu_read_unlock();
838                 goto out;
839         }
840         cf_sk->headroom = LL_RESERVED_SPACE_EXTRA(dev, headroom);
841         mtu = dev->mtu;
842         rcu_read_unlock();
843 
844         cf_sk->tailroom = tailroom;
845         cf_sk->maxframe = mtu - (headroom + tailroom);
846         if (cf_sk->maxframe < 1) {
847                 pr_warn("CAIF Interface MTU too small (%d)\n", dev->mtu);
848                 err = -ENODEV;
849                 goto out;
850         }
851 
852         err = -EINPROGRESS;
853 wait_connect:
854 
855         if (sk->sk_state != CAIF_CONNECTED && (flags & O_NONBLOCK))
856                 goto out;
857 
858         timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
859 
860         release_sock(sk);
861         err = -ERESTARTSYS;
862         timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
863                         sk->sk_state != CAIF_CONNECTING,
864                         timeo);
865         lock_sock(sk);
866         if (timeo < 0)
867                 goto out; /* -ERESTARTSYS */
868 
869         err = -ETIMEDOUT;
870         if (timeo == 0 && sk->sk_state != CAIF_CONNECTED)
871                 goto out;
872         if (sk->sk_state != CAIF_CONNECTED) {
873                 sock->state = SS_UNCONNECTED;
874                 err = sock_error(sk);
875                 if (!err)
876                         err = -ECONNREFUSED;
877                 goto out;
878         }
879         sock->state = SS_CONNECTED;
880         err = 0;
881 out:
882         release_sock(sk);
883         return err;
884 }
885 
886 /*
887  * caif_release() - Disconnect a CAIF Socket
888  * Copied and modified af_irda.c:irda_release().
889  */
890 static int caif_release(struct socket *sock)
891 {
892         struct sock *sk = sock->sk;
893         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
894 
895         if (!sk)
896                 return 0;
897 
898         set_tx_flow_off(cf_sk);
899 
900         /*
901          * Ensure that packets are not queued after this point in time.
902          * caif_queue_rcv_skb checks SOCK_DEAD holding the queue lock,
903          * this ensures no packets when sock is dead.
904          */
905         spin_lock_bh(&sk->sk_receive_queue.lock);
906         sock_set_flag(sk, SOCK_DEAD);
907         spin_unlock_bh(&sk->sk_receive_queue.lock);
908         sock->sk = NULL;
909 
910         WARN_ON(IS_ERR(cf_sk->debugfs_socket_dir));
911         if (cf_sk->debugfs_socket_dir != NULL)
912                 debugfs_remove_recursive(cf_sk->debugfs_socket_dir);
913 
914         lock_sock(&(cf_sk->sk));
915         sk->sk_state = CAIF_DISCONNECTED;
916         sk->sk_shutdown = SHUTDOWN_MASK;
917 
918         caif_disconnect_client(sock_net(sk), &cf_sk->layer);
919         cf_sk->sk.sk_socket->state = SS_DISCONNECTING;
920         wake_up_interruptible_poll(sk_sleep(sk), POLLERR|POLLHUP);
921 
922         sock_orphan(sk);
923         sk_stream_kill_queues(&cf_sk->sk);
924         release_sock(sk);
925         sock_put(sk);
926         return 0;
927 }
928 
929 /* Copied from af_unix.c:unix_poll(), added CAIF tx_flow handling */
930 static unsigned int caif_poll(struct file *file,
931                               struct socket *sock, poll_table *wait)
932 {
933         struct sock *sk = sock->sk;
934         unsigned int mask;
935         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
936 
937         sock_poll_wait(file, sk_sleep(sk), wait);
938         mask = 0;
939 
940         /* exceptional events? */
941         if (sk->sk_err)
942                 mask |= POLLERR;
943         if (sk->sk_shutdown == SHUTDOWN_MASK)
944                 mask |= POLLHUP;
945         if (sk->sk_shutdown & RCV_SHUTDOWN)
946                 mask |= POLLRDHUP;
947 
948         /* readable? */
949         if (!skb_queue_empty(&sk->sk_receive_queue) ||
950                 (sk->sk_shutdown & RCV_SHUTDOWN))
951                 mask |= POLLIN | POLLRDNORM;
952 
953         /*
954          * we set writable also when the other side has shut down the
955          * connection. This prevents stuck sockets.
956          */
957         if (sock_writeable(sk) && tx_flow_is_on(cf_sk))
958                 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
959 
960         return mask;
961 }
962 
963 static const struct proto_ops caif_seqpacket_ops = {
964         .family = PF_CAIF,
965         .owner = THIS_MODULE,
966         .release = caif_release,
967         .bind = sock_no_bind,
968         .connect = caif_connect,
969         .socketpair = sock_no_socketpair,
970         .accept = sock_no_accept,
971         .getname = sock_no_getname,
972         .poll = caif_poll,
973         .ioctl = sock_no_ioctl,
974         .listen = sock_no_listen,
975         .shutdown = sock_no_shutdown,
976         .setsockopt = setsockopt,
977         .getsockopt = sock_no_getsockopt,
978         .sendmsg = caif_seqpkt_sendmsg,
979         .recvmsg = caif_seqpkt_recvmsg,
980         .mmap = sock_no_mmap,
981         .sendpage = sock_no_sendpage,
982 };
983 
984 static const struct proto_ops caif_stream_ops = {
985         .family = PF_CAIF,
986         .owner = THIS_MODULE,
987         .release = caif_release,
988         .bind = sock_no_bind,
989         .connect = caif_connect,
990         .socketpair = sock_no_socketpair,
991         .accept = sock_no_accept,
992         .getname = sock_no_getname,
993         .poll = caif_poll,
994         .ioctl = sock_no_ioctl,
995         .listen = sock_no_listen,
996         .shutdown = sock_no_shutdown,
997         .setsockopt = setsockopt,
998         .getsockopt = sock_no_getsockopt,
999         .sendmsg = caif_stream_sendmsg,
1000         .recvmsg = caif_stream_recvmsg,
1001         .mmap = sock_no_mmap,
1002         .sendpage = sock_no_sendpage,
1003 };
1004 
1005 /* This function is called when a socket is finally destroyed. */
1006 static void caif_sock_destructor(struct sock *sk)
1007 {
1008         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
1009         caif_assert(!atomic_read(&sk->sk_wmem_alloc));
1010         caif_assert(sk_unhashed(sk));
1011         caif_assert(!sk->sk_socket);
1012         if (!sock_flag(sk, SOCK_DEAD)) {
1013                 pr_debug("Attempt to release alive CAIF socket: %p\n", sk);
1014                 return;
1015         }
1016         sk_stream_kill_queues(&cf_sk->sk);
1017         caif_free_client(&cf_sk->layer);
1018 }
1019 
1020 static int caif_create(struct net *net, struct socket *sock, int protocol,
1021                        int kern)
1022 {
1023         struct sock *sk = NULL;
1024         struct caifsock *cf_sk = NULL;
1025         static struct proto prot = {.name = "PF_CAIF",
1026                 .owner = THIS_MODULE,
1027                 .obj_size = sizeof(struct caifsock),
1028         };
1029 
1030         if (!capable(CAP_SYS_ADMIN) && !capable(CAP_NET_ADMIN))
1031                 return -EPERM;
1032         /*
1033          * The sock->type specifies the socket type to use.
1034          * The CAIF socket is a packet stream in the sense
1035          * that it is packet based. CAIF trusts the reliability
1036          * of the link, no resending is implemented.
1037          */
1038         if (sock->type == SOCK_SEQPACKET)
1039                 sock->ops = &caif_seqpacket_ops;
1040         else if (sock->type == SOCK_STREAM)
1041                 sock->ops = &caif_stream_ops;
1042         else
1043                 return -ESOCKTNOSUPPORT;
1044 
1045         if (protocol < 0 || protocol >= CAIFPROTO_MAX)
1046                 return -EPROTONOSUPPORT;
1047         /*
1048          * Set the socket state to unconnected.  The socket state
1049          * is really not used at all in the net/core or socket.c but the
1050          * initialization makes sure that sock->state is not uninitialized.
1051          */
1052         sk = sk_alloc(net, PF_CAIF, GFP_KERNEL, &prot);
1053         if (!sk)
1054                 return -ENOMEM;
1055 
1056         cf_sk = container_of(sk, struct caifsock, sk);
1057 
1058         /* Store the protocol */
1059         sk->sk_protocol = (unsigned char) protocol;
1060 
1061         /* Initialize default priority for well-known cases */
1062         switch (protocol) {
1063         case CAIFPROTO_AT:
1064                 sk->sk_priority = TC_PRIO_CONTROL;
1065                 break;
1066         case CAIFPROTO_RFM:
1067                 sk->sk_priority = TC_PRIO_INTERACTIVE_BULK;
1068                 break;
1069         default:
1070                 sk->sk_priority = TC_PRIO_BESTEFFORT;
1071         }
1072 
1073         /*
1074          * Lock in order to try to stop someone from opening the socket
1075          * too early.
1076          */
1077         lock_sock(&(cf_sk->sk));
1078 
1079         /* Initialize the nozero default sock structure data. */
1080         sock_init_data(sock, sk);
1081         sk->sk_destruct = caif_sock_destructor;
1082 
1083         mutex_init(&cf_sk->readlock); /* single task reading lock */
1084         cf_sk->layer.ctrlcmd = caif_ctrl_cb;
1085         cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
1086         cf_sk->sk.sk_state = CAIF_DISCONNECTED;
1087 
1088         set_tx_flow_off(cf_sk);
1089         set_rx_flow_on(cf_sk);
1090 
1091         /* Set default options on configuration */
1092         cf_sk->conn_req.link_selector = CAIF_LINK_LOW_LATENCY;
1093         cf_sk->conn_req.protocol = protocol;
1094         release_sock(&cf_sk->sk);
1095         return 0;
1096 }
1097 
1098 
1099 static struct net_proto_family caif_family_ops = {
1100         .family = PF_CAIF,
1101         .create = caif_create,
1102         .owner = THIS_MODULE,
1103 };
1104 
1105 static int __init caif_sktinit_module(void)
1106 {
1107         int err = sock_register(&caif_family_ops);
1108         if (!err)
1109                 return err;
1110         return 0;
1111 }
1112 
1113 static void __exit caif_sktexit_module(void)
1114 {
1115         sock_unregister(PF_CAIF);
1116 }
1117 module_init(caif_sktinit_module);
1118 module_exit(caif_sktexit_module);
1119 

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