Version:  2.0.40 2.2.26 2.4.37 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1

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 socket *sock, struct msghdr *m,
275                                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 (flags & MSG_OOB)
285                 goto read_error;
286 
287         skb = skb_recv_datagram(sk, flags, 0 , &ret);
288         if (!skb)
289                 goto read_error;
290         copylen = skb->len;
291         if (len < copylen) {
292                 m->msg_flags |= MSG_TRUNC;
293                 copylen = len;
294         }
295 
296         ret = skb_copy_datagram_msg(skb, 0, m, copylen);
297         if (ret)
298                 goto out_free;
299 
300         ret = (flags & MSG_TRUNC) ? skb->len : copylen;
301 out_free:
302         skb_free_datagram(sk, skb);
303         caif_check_flow_release(sk);
304         return ret;
305 
306 read_error:
307         return ret;
308 }
309 
310 
311 /* Copied from unix_stream_wait_data, identical except for lock call. */
312 static long caif_stream_data_wait(struct sock *sk, long timeo)
313 {
314         DEFINE_WAIT(wait);
315         lock_sock(sk);
316 
317         for (;;) {
318                 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
319 
320                 if (!skb_queue_empty(&sk->sk_receive_queue) ||
321                         sk->sk_err ||
322                         sk->sk_state != CAIF_CONNECTED ||
323                         sock_flag(sk, SOCK_DEAD) ||
324                         (sk->sk_shutdown & RCV_SHUTDOWN) ||
325                         signal_pending(current) ||
326                         !timeo)
327                         break;
328 
329                 set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
330                 release_sock(sk);
331                 timeo = schedule_timeout(timeo);
332                 lock_sock(sk);
333 
334                 if (sock_flag(sk, SOCK_DEAD))
335                         break;
336 
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 socket *sock, struct msghdr *msg,
351                                size_t size, int flags)
352 {
353         struct sock *sk = sock->sk;
354         int copied = 0;
355         int target;
356         int err = 0;
357         long timeo;
358 
359         err = -EOPNOTSUPP;
360         if (flags&MSG_OOB)
361                 goto out;
362 
363         /*
364          * Lock the socket to prevent queue disordering
365          * while sleeps in memcpy_tomsg
366          */
367         err = -EAGAIN;
368         if (sk->sk_state == CAIF_CONNECTING)
369                 goto out;
370 
371         caif_read_lock(sk);
372         target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
373         timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT);
374 
375         do {
376                 int chunk;
377                 struct sk_buff *skb;
378 
379                 lock_sock(sk);
380                 if (sock_flag(sk, SOCK_DEAD)) {
381                         err = -ECONNRESET;
382                         goto unlock;
383                 }
384                 skb = skb_dequeue(&sk->sk_receive_queue);
385                 caif_check_flow_release(sk);
386 
387                 if (skb == NULL) {
388                         if (copied >= target)
389                                 goto unlock;
390                         /*
391                          *      POSIX 1003.1g mandates this order.
392                          */
393                         err = sock_error(sk);
394                         if (err)
395                                 goto unlock;
396                         err = -ECONNRESET;
397                         if (sk->sk_shutdown & RCV_SHUTDOWN)
398                                 goto unlock;
399 
400                         err = -EPIPE;
401                         if (sk->sk_state != CAIF_CONNECTED)
402                                 goto unlock;
403                         if (sock_flag(sk, SOCK_DEAD))
404                                 goto unlock;
405 
406                         release_sock(sk);
407 
408                         err = -EAGAIN;
409                         if (!timeo)
410                                 break;
411 
412                         caif_read_unlock(sk);
413 
414                         timeo = caif_stream_data_wait(sk, timeo);
415 
416                         if (signal_pending(current)) {
417                                 err = sock_intr_errno(timeo);
418                                 goto out;
419                         }
420                         caif_read_lock(sk);
421                         continue;
422 unlock:
423                         release_sock(sk);
424                         break;
425                 }
426                 release_sock(sk);
427                 chunk = min_t(unsigned int, skb->len, size);
428                 if (memcpy_to_msg(msg, skb->data, chunk)) {
429                         skb_queue_head(&sk->sk_receive_queue, skb);
430                         if (copied == 0)
431                                 copied = -EFAULT;
432                         break;
433                 }
434                 copied += chunk;
435                 size -= chunk;
436 
437                 /* Mark read part of skb as used */
438                 if (!(flags & MSG_PEEK)) {
439                         skb_pull(skb, chunk);
440 
441                         /* put the skb back if we didn't use it up. */
442                         if (skb->len) {
443                                 skb_queue_head(&sk->sk_receive_queue, skb);
444                                 break;
445                         }
446                         kfree_skb(skb);
447 
448                 } else {
449                         /*
450                          * It is questionable, see note in unix_dgram_recvmsg.
451                          */
452                         /* put message back and return */
453                         skb_queue_head(&sk->sk_receive_queue, skb);
454                         break;
455                 }
456         } while (size);
457         caif_read_unlock(sk);
458 
459 out:
460         return copied ? : err;
461 }
462 
463 /*
464  * Copied from sock.c:sock_wait_for_wmem, but change to wait for
465  * CAIF flow-on and sock_writable.
466  */
467 static long caif_wait_for_flow_on(struct caifsock *cf_sk,
468                                   int wait_writeable, long timeo, int *err)
469 {
470         struct sock *sk = &cf_sk->sk;
471         DEFINE_WAIT(wait);
472         for (;;) {
473                 *err = 0;
474                 if (tx_flow_is_on(cf_sk) &&
475                         (!wait_writeable || sock_writeable(&cf_sk->sk)))
476                         break;
477                 *err = -ETIMEDOUT;
478                 if (!timeo)
479                         break;
480                 *err = -ERESTARTSYS;
481                 if (signal_pending(current))
482                         break;
483                 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
484                 *err = -ECONNRESET;
485                 if (sk->sk_shutdown & SHUTDOWN_MASK)
486                         break;
487                 *err = -sk->sk_err;
488                 if (sk->sk_err)
489                         break;
490                 *err = -EPIPE;
491                 if (cf_sk->sk.sk_state != CAIF_CONNECTED)
492                         break;
493                 timeo = schedule_timeout(timeo);
494         }
495         finish_wait(sk_sleep(sk), &wait);
496         return timeo;
497 }
498 
499 /*
500  * Transmit a SKB. The device may temporarily request re-transmission
501  * by returning EAGAIN.
502  */
503 static int transmit_skb(struct sk_buff *skb, struct caifsock *cf_sk,
504                         int noblock, long timeo)
505 {
506         struct cfpkt *pkt;
507 
508         pkt = cfpkt_fromnative(CAIF_DIR_OUT, skb);
509         memset(skb->cb, 0, sizeof(struct caif_payload_info));
510         cfpkt_set_prio(pkt, cf_sk->sk.sk_priority);
511 
512         if (cf_sk->layer.dn == NULL) {
513                 kfree_skb(skb);
514                 return -EINVAL;
515         }
516 
517         return cf_sk->layer.dn->transmit(cf_sk->layer.dn, pkt);
518 }
519 
520 /* Copied from af_unix:unix_dgram_sendmsg, and adapted to CAIF */
521 static int caif_seqpkt_sendmsg(struct socket *sock, struct msghdr *msg,
522                                size_t len)
523 {
524         struct sock *sk = sock->sk;
525         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
526         int buffer_size;
527         int ret = 0;
528         struct sk_buff *skb = NULL;
529         int noblock;
530         long timeo;
531         caif_assert(cf_sk);
532         ret = sock_error(sk);
533         if (ret)
534                 goto err;
535 
536         ret = -EOPNOTSUPP;
537         if (msg->msg_flags&MSG_OOB)
538                 goto err;
539 
540         ret = -EOPNOTSUPP;
541         if (msg->msg_namelen)
542                 goto err;
543 
544         ret = -EINVAL;
545         if (unlikely(msg->msg_iter.iov->iov_base == NULL))
546                 goto err;
547         noblock = msg->msg_flags & MSG_DONTWAIT;
548 
549         timeo = sock_sndtimeo(sk, noblock);
550         timeo = caif_wait_for_flow_on(container_of(sk, struct caifsock, sk),
551                                 1, timeo, &ret);
552 
553         if (ret)
554                 goto err;
555         ret = -EPIPE;
556         if (cf_sk->sk.sk_state != CAIF_CONNECTED ||
557                 sock_flag(sk, SOCK_DEAD) ||
558                 (sk->sk_shutdown & RCV_SHUTDOWN))
559                 goto err;
560 
561         /* Error if trying to write more than maximum frame size. */
562         ret = -EMSGSIZE;
563         if (len > cf_sk->maxframe && cf_sk->sk.sk_protocol != CAIFPROTO_RFM)
564                 goto err;
565 
566         buffer_size = len + cf_sk->headroom + cf_sk->tailroom;
567 
568         ret = -ENOMEM;
569         skb = sock_alloc_send_skb(sk, buffer_size, noblock, &ret);
570 
571         if (!skb || skb_tailroom(skb) < buffer_size)
572                 goto err;
573 
574         skb_reserve(skb, cf_sk->headroom);
575 
576         ret = memcpy_from_msg(skb_put(skb, len), msg, len);
577 
578         if (ret)
579                 goto err;
580         ret = transmit_skb(skb, cf_sk, noblock, timeo);
581         if (ret < 0)
582                 /* skb is already freed */
583                 return ret;
584 
585         return len;
586 err:
587         kfree_skb(skb);
588         return ret;
589 }
590 
591 /*
592  * Copied from unix_stream_sendmsg and adapted to CAIF:
593  * Changed removed permission handling and added waiting for flow on
594  * and other minor adaptations.
595  */
596 static int caif_stream_sendmsg(struct socket *sock, struct msghdr *msg,
597                                size_t len)
598 {
599         struct sock *sk = sock->sk;
600         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
601         int err, size;
602         struct sk_buff *skb;
603         int sent = 0;
604         long timeo;
605 
606         err = -EOPNOTSUPP;
607         if (unlikely(msg->msg_flags&MSG_OOB))
608                 goto out_err;
609 
610         if (unlikely(msg->msg_namelen))
611                 goto out_err;
612 
613         timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
614         timeo = caif_wait_for_flow_on(cf_sk, 1, timeo, &err);
615 
616         if (unlikely(sk->sk_shutdown & SEND_SHUTDOWN))
617                 goto pipe_err;
618 
619         while (sent < len) {
620 
621                 size = len-sent;
622 
623                 if (size > cf_sk->maxframe)
624                         size = cf_sk->maxframe;
625 
626                 /* If size is more than half of sndbuf, chop up message */
627                 if (size > ((sk->sk_sndbuf >> 1) - 64))
628                         size = (sk->sk_sndbuf >> 1) - 64;
629 
630                 if (size > SKB_MAX_ALLOC)
631                         size = SKB_MAX_ALLOC;
632 
633                 skb = sock_alloc_send_skb(sk,
634                                         size + cf_sk->headroom +
635                                         cf_sk->tailroom,
636                                         msg->msg_flags&MSG_DONTWAIT,
637                                         &err);
638                 if (skb == NULL)
639                         goto out_err;
640 
641                 skb_reserve(skb, cf_sk->headroom);
642                 /*
643                  *      If you pass two values to the sock_alloc_send_skb
644                  *      it tries to grab the large buffer with GFP_NOFS
645                  *      (which can fail easily), and if it fails grab the
646                  *      fallback size buffer which is under a page and will
647                  *      succeed. [Alan]
648                  */
649                 size = min_t(int, size, skb_tailroom(skb));
650 
651                 err = memcpy_from_msg(skb_put(skb, size), msg, size);
652                 if (err) {
653                         kfree_skb(skb);
654                         goto out_err;
655                 }
656                 err = transmit_skb(skb, cf_sk,
657                                 msg->msg_flags&MSG_DONTWAIT, timeo);
658                 if (err < 0)
659                         /* skb is already freed */
660                         goto pipe_err;
661 
662                 sent += size;
663         }
664 
665         return sent;
666 
667 pipe_err:
668         if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
669                 send_sig(SIGPIPE, current, 0);
670         err = -EPIPE;
671 out_err:
672         return sent ? : err;
673 }
674 
675 static int setsockopt(struct socket *sock,
676                       int lvl, int opt, char __user *ov, unsigned int ol)
677 {
678         struct sock *sk = sock->sk;
679         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
680         int linksel;
681 
682         if (cf_sk->sk.sk_socket->state != SS_UNCONNECTED)
683                 return -ENOPROTOOPT;
684 
685         switch (opt) {
686         case CAIFSO_LINK_SELECT:
687                 if (ol < sizeof(int))
688                         return -EINVAL;
689                 if (lvl != SOL_CAIF)
690                         goto bad_sol;
691                 if (copy_from_user(&linksel, ov, sizeof(int)))
692                         return -EINVAL;
693                 lock_sock(&(cf_sk->sk));
694                 cf_sk->conn_req.link_selector = linksel;
695                 release_sock(&cf_sk->sk);
696                 return 0;
697 
698         case CAIFSO_REQ_PARAM:
699                 if (lvl != SOL_CAIF)
700                         goto bad_sol;
701                 if (cf_sk->sk.sk_protocol != CAIFPROTO_UTIL)
702                         return -ENOPROTOOPT;
703                 lock_sock(&(cf_sk->sk));
704                 if (ol > sizeof(cf_sk->conn_req.param.data) ||
705                         copy_from_user(&cf_sk->conn_req.param.data, ov, ol)) {
706                         release_sock(&cf_sk->sk);
707                         return -EINVAL;
708                 }
709                 cf_sk->conn_req.param.size = ol;
710                 release_sock(&cf_sk->sk);
711                 return 0;
712 
713         default:
714                 return -ENOPROTOOPT;
715         }
716 
717         return 0;
718 bad_sol:
719         return -ENOPROTOOPT;
720 
721 }
722 
723 /*
724  * caif_connect() - Connect a CAIF Socket
725  * Copied and modified af_irda.c:irda_connect().
726  *
727  * Note : by consulting "errno", the user space caller may learn the cause
728  * of the failure. Most of them are visible in the function, others may come
729  * from subroutines called and are listed here :
730  *  o -EAFNOSUPPORT: bad socket family or type.
731  *  o -ESOCKTNOSUPPORT: bad socket type or protocol
732  *  o -EINVAL: bad socket address, or CAIF link type
733  *  o -ECONNREFUSED: remote end refused the connection.
734  *  o -EINPROGRESS: connect request sent but timed out (or non-blocking)
735  *  o -EISCONN: already connected.
736  *  o -ETIMEDOUT: Connection timed out (send timeout)
737  *  o -ENODEV: No link layer to send request
738  *  o -ECONNRESET: Received Shutdown indication or lost link layer
739  *  o -ENOMEM: Out of memory
740  *
741  *  State Strategy:
742  *  o sk_state: holds the CAIF_* protocol state, it's updated by
743  *      caif_ctrl_cb.
744  *  o sock->state: holds the SS_* socket state and is updated by connect and
745  *      disconnect.
746  */
747 static int caif_connect(struct socket *sock, struct sockaddr *uaddr,
748                         int addr_len, int flags)
749 {
750         struct sock *sk = sock->sk;
751         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
752         long timeo;
753         int err;
754         int ifindex, headroom, tailroom;
755         unsigned int mtu;
756         struct net_device *dev;
757 
758         lock_sock(sk);
759 
760         err = -EAFNOSUPPORT;
761         if (uaddr->sa_family != AF_CAIF)
762                 goto out;
763 
764         switch (sock->state) {
765         case SS_UNCONNECTED:
766                 /* Normal case, a fresh connect */
767                 caif_assert(sk->sk_state == CAIF_DISCONNECTED);
768                 break;
769         case SS_CONNECTING:
770                 switch (sk->sk_state) {
771                 case CAIF_CONNECTED:
772                         sock->state = SS_CONNECTED;
773                         err = -EISCONN;
774                         goto out;
775                 case CAIF_DISCONNECTED:
776                         /* Reconnect allowed */
777                         break;
778                 case CAIF_CONNECTING:
779                         err = -EALREADY;
780                         if (flags & O_NONBLOCK)
781                                 goto out;
782                         goto wait_connect;
783                 }
784                 break;
785         case SS_CONNECTED:
786                 caif_assert(sk->sk_state == CAIF_CONNECTED ||
787                                 sk->sk_state == CAIF_DISCONNECTED);
788                 if (sk->sk_shutdown & SHUTDOWN_MASK) {
789                         /* Allow re-connect after SHUTDOWN_IND */
790                         caif_disconnect_client(sock_net(sk), &cf_sk->layer);
791                         caif_free_client(&cf_sk->layer);
792                         break;
793                 }
794                 /* No reconnect on a seqpacket socket */
795                 err = -EISCONN;
796                 goto out;
797         case SS_DISCONNECTING:
798         case SS_FREE:
799                 caif_assert(1); /*Should never happen */
800                 break;
801         }
802         sk->sk_state = CAIF_DISCONNECTED;
803         sock->state = SS_UNCONNECTED;
804         sk_stream_kill_queues(&cf_sk->sk);
805 
806         err = -EINVAL;
807         if (addr_len != sizeof(struct sockaddr_caif))
808                 goto out;
809 
810         memcpy(&cf_sk->conn_req.sockaddr, uaddr,
811                 sizeof(struct sockaddr_caif));
812 
813         /* Move to connecting socket, start sending Connect Requests */
814         sock->state = SS_CONNECTING;
815         sk->sk_state = CAIF_CONNECTING;
816 
817         /* Check priority value comming from socket */
818         /* if priority value is out of range it will be ajusted */
819         if (cf_sk->sk.sk_priority > CAIF_PRIO_MAX)
820                 cf_sk->conn_req.priority = CAIF_PRIO_MAX;
821         else if (cf_sk->sk.sk_priority < CAIF_PRIO_MIN)
822                 cf_sk->conn_req.priority = CAIF_PRIO_MIN;
823         else
824                 cf_sk->conn_req.priority = cf_sk->sk.sk_priority;
825 
826         /*ifindex = id of the interface.*/
827         cf_sk->conn_req.ifindex = cf_sk->sk.sk_bound_dev_if;
828 
829         cf_sk->layer.receive = caif_sktrecv_cb;
830 
831         err = caif_connect_client(sock_net(sk), &cf_sk->conn_req,
832                                 &cf_sk->layer, &ifindex, &headroom, &tailroom);
833 
834         if (err < 0) {
835                 cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
836                 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
837                 goto out;
838         }
839 
840         err = -ENODEV;
841         rcu_read_lock();
842         dev = dev_get_by_index_rcu(sock_net(sk), ifindex);
843         if (!dev) {
844                 rcu_read_unlock();
845                 goto out;
846         }
847         cf_sk->headroom = LL_RESERVED_SPACE_EXTRA(dev, headroom);
848         mtu = dev->mtu;
849         rcu_read_unlock();
850 
851         cf_sk->tailroom = tailroom;
852         cf_sk->maxframe = mtu - (headroom + tailroom);
853         if (cf_sk->maxframe < 1) {
854                 pr_warn("CAIF Interface MTU too small (%d)\n", dev->mtu);
855                 err = -ENODEV;
856                 goto out;
857         }
858 
859         err = -EINPROGRESS;
860 wait_connect:
861 
862         if (sk->sk_state != CAIF_CONNECTED && (flags & O_NONBLOCK))
863                 goto out;
864 
865         timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
866 
867         release_sock(sk);
868         err = -ERESTARTSYS;
869         timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
870                         sk->sk_state != CAIF_CONNECTING,
871                         timeo);
872         lock_sock(sk);
873         if (timeo < 0)
874                 goto out; /* -ERESTARTSYS */
875 
876         err = -ETIMEDOUT;
877         if (timeo == 0 && sk->sk_state != CAIF_CONNECTED)
878                 goto out;
879         if (sk->sk_state != CAIF_CONNECTED) {
880                 sock->state = SS_UNCONNECTED;
881                 err = sock_error(sk);
882                 if (!err)
883                         err = -ECONNREFUSED;
884                 goto out;
885         }
886         sock->state = SS_CONNECTED;
887         err = 0;
888 out:
889         release_sock(sk);
890         return err;
891 }
892 
893 /*
894  * caif_release() - Disconnect a CAIF Socket
895  * Copied and modified af_irda.c:irda_release().
896  */
897 static int caif_release(struct socket *sock)
898 {
899         struct sock *sk = sock->sk;
900         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
901 
902         if (!sk)
903                 return 0;
904 
905         set_tx_flow_off(cf_sk);
906 
907         /*
908          * Ensure that packets are not queued after this point in time.
909          * caif_queue_rcv_skb checks SOCK_DEAD holding the queue lock,
910          * this ensures no packets when sock is dead.
911          */
912         spin_lock_bh(&sk->sk_receive_queue.lock);
913         sock_set_flag(sk, SOCK_DEAD);
914         spin_unlock_bh(&sk->sk_receive_queue.lock);
915         sock->sk = NULL;
916 
917         WARN_ON(IS_ERR(cf_sk->debugfs_socket_dir));
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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