Version:  2.0.40 2.2.26 2.4.37 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 4.2

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 void caif_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
125 {
126         int err;
127         unsigned long flags;
128         struct sk_buff_head *list = &sk->sk_receive_queue;
129         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
130         bool queued = false;
131 
132         if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
133                 (unsigned int)sk->sk_rcvbuf && rx_flow_is_on(cf_sk)) {
134                 net_dbg_ratelimited("sending flow OFF (queue len = %d %d)\n",
135                                     atomic_read(&cf_sk->sk.sk_rmem_alloc),
136                                     sk_rcvbuf_lowwater(cf_sk));
137                 set_rx_flow_off(cf_sk);
138                 caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ);
139         }
140 
141         err = sk_filter(sk, skb);
142         if (err)
143                 goto out;
144 
145         if (!sk_rmem_schedule(sk, skb, skb->truesize) && rx_flow_is_on(cf_sk)) {
146                 set_rx_flow_off(cf_sk);
147                 net_dbg_ratelimited("sending flow OFF due to rmem_schedule\n");
148                 caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ);
149         }
150         skb->dev = NULL;
151         skb_set_owner_r(skb, sk);
152         spin_lock_irqsave(&list->lock, flags);
153         queued = !sock_flag(sk, SOCK_DEAD);
154         if (queued)
155                 __skb_queue_tail(list, skb);
156         spin_unlock_irqrestore(&list->lock, flags);
157 out:
158         if (queued)
159                 sk->sk_data_ready(sk);
160         else
161                 kfree_skb(skb);
162 }
163 
164 /* Packet Receive Callback function called from CAIF Stack */
165 static int caif_sktrecv_cb(struct cflayer *layr, struct cfpkt *pkt)
166 {
167         struct caifsock *cf_sk;
168         struct sk_buff *skb;
169 
170         cf_sk = container_of(layr, struct caifsock, layer);
171         skb = cfpkt_tonative(pkt);
172 
173         if (unlikely(cf_sk->sk.sk_state != CAIF_CONNECTED)) {
174                 kfree_skb(skb);
175                 return 0;
176         }
177         caif_queue_rcv_skb(&cf_sk->sk, skb);
178         return 0;
179 }
180 
181 static void cfsk_hold(struct cflayer *layr)
182 {
183         struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
184         sock_hold(&cf_sk->sk);
185 }
186 
187 static void cfsk_put(struct cflayer *layr)
188 {
189         struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
190         sock_put(&cf_sk->sk);
191 }
192 
193 /* Packet Control Callback function called from CAIF */
194 static void caif_ctrl_cb(struct cflayer *layr,
195                          enum caif_ctrlcmd flow,
196                          int phyid)
197 {
198         struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
199         switch (flow) {
200         case CAIF_CTRLCMD_FLOW_ON_IND:
201                 /* OK from modem to start sending again */
202                 set_tx_flow_on(cf_sk);
203                 cf_sk->sk.sk_state_change(&cf_sk->sk);
204                 break;
205 
206         case CAIF_CTRLCMD_FLOW_OFF_IND:
207                 /* Modem asks us to shut up */
208                 set_tx_flow_off(cf_sk);
209                 cf_sk->sk.sk_state_change(&cf_sk->sk);
210                 break;
211 
212         case CAIF_CTRLCMD_INIT_RSP:
213                 /* We're now connected */
214                 caif_client_register_refcnt(&cf_sk->layer,
215                                                 cfsk_hold, cfsk_put);
216                 cf_sk->sk.sk_state = CAIF_CONNECTED;
217                 set_tx_flow_on(cf_sk);
218                 cf_sk->sk.sk_shutdown = 0;
219                 cf_sk->sk.sk_state_change(&cf_sk->sk);
220                 break;
221 
222         case CAIF_CTRLCMD_DEINIT_RSP:
223                 /* We're now disconnected */
224                 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
225                 cf_sk->sk.sk_state_change(&cf_sk->sk);
226                 break;
227 
228         case CAIF_CTRLCMD_INIT_FAIL_RSP:
229                 /* Connect request failed */
230                 cf_sk->sk.sk_err = ECONNREFUSED;
231                 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
232                 cf_sk->sk.sk_shutdown = SHUTDOWN_MASK;
233                 /*
234                  * Socket "standards" seems to require POLLOUT to
235                  * be set at connect failure.
236                  */
237                 set_tx_flow_on(cf_sk);
238                 cf_sk->sk.sk_state_change(&cf_sk->sk);
239                 break;
240 
241         case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
242                 /* Modem has closed this connection, or device is down. */
243                 cf_sk->sk.sk_shutdown = SHUTDOWN_MASK;
244                 cf_sk->sk.sk_err = ECONNRESET;
245                 set_rx_flow_on(cf_sk);
246                 cf_sk->sk.sk_error_report(&cf_sk->sk);
247                 break;
248 
249         default:
250                 pr_debug("Unexpected flow command %d\n", flow);
251         }
252 }
253 
254 static void caif_check_flow_release(struct sock *sk)
255 {
256         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
257 
258         if (rx_flow_is_on(cf_sk))
259                 return;
260 
261         if (atomic_read(&sk->sk_rmem_alloc) <= sk_rcvbuf_lowwater(cf_sk)) {
262                         set_rx_flow_on(cf_sk);
263                         caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_ON_REQ);
264         }
265 }
266 
267 /*
268  * Copied from unix_dgram_recvmsg, but removed credit checks,
269  * changed locking, address handling and added MSG_TRUNC.
270  */
271 static int caif_seqpkt_recvmsg(struct socket *sock, struct msghdr *m,
272                                size_t len, int flags)
273 
274 {
275         struct sock *sk = sock->sk;
276         struct sk_buff *skb;
277         int ret;
278         int copylen;
279 
280         ret = -EOPNOTSUPP;
281         if (flags & MSG_OOB)
282                 goto read_error;
283 
284         skb = skb_recv_datagram(sk, flags, 0 , &ret);
285         if (!skb)
286                 goto read_error;
287         copylen = skb->len;
288         if (len < copylen) {
289                 m->msg_flags |= MSG_TRUNC;
290                 copylen = len;
291         }
292 
293         ret = skb_copy_datagram_msg(skb, 0, m, copylen);
294         if (ret)
295                 goto out_free;
296 
297         ret = (flags & MSG_TRUNC) ? skb->len : copylen;
298 out_free:
299         skb_free_datagram(sk, skb);
300         caif_check_flow_release(sk);
301         return ret;
302 
303 read_error:
304         return ret;
305 }
306 
307 
308 /* Copied from unix_stream_wait_data, identical except for lock call. */
309 static long caif_stream_data_wait(struct sock *sk, long timeo)
310 {
311         DEFINE_WAIT(wait);
312         lock_sock(sk);
313 
314         for (;;) {
315                 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
316 
317                 if (!skb_queue_empty(&sk->sk_receive_queue) ||
318                         sk->sk_err ||
319                         sk->sk_state != CAIF_CONNECTED ||
320                         sock_flag(sk, SOCK_DEAD) ||
321                         (sk->sk_shutdown & RCV_SHUTDOWN) ||
322                         signal_pending(current) ||
323                         !timeo)
324                         break;
325 
326                 set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
327                 release_sock(sk);
328                 timeo = schedule_timeout(timeo);
329                 lock_sock(sk);
330 
331                 if (sock_flag(sk, SOCK_DEAD))
332                         break;
333 
334                 clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
335         }
336 
337         finish_wait(sk_sleep(sk), &wait);
338         release_sock(sk);
339         return timeo;
340 }
341 
342 
343 /*
344  * Copied from unix_stream_recvmsg, but removed credit checks,
345  * changed locking calls, changed address handling.
346  */
347 static int caif_stream_recvmsg(struct socket *sock, struct msghdr *msg,
348                                size_t size, int flags)
349 {
350         struct sock *sk = sock->sk;
351         int copied = 0;
352         int target;
353         int err = 0;
354         long timeo;
355 
356         err = -EOPNOTSUPP;
357         if (flags&MSG_OOB)
358                 goto out;
359 
360         /*
361          * Lock the socket to prevent queue disordering
362          * while sleeps in memcpy_tomsg
363          */
364         err = -EAGAIN;
365         if (sk->sk_state == CAIF_CONNECTING)
366                 goto out;
367 
368         caif_read_lock(sk);
369         target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
370         timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT);
371 
372         do {
373                 int chunk;
374                 struct sk_buff *skb;
375 
376                 lock_sock(sk);
377                 if (sock_flag(sk, SOCK_DEAD)) {
378                         err = -ECONNRESET;
379                         goto unlock;
380                 }
381                 skb = skb_dequeue(&sk->sk_receive_queue);
382                 caif_check_flow_release(sk);
383 
384                 if (skb == NULL) {
385                         if (copied >= target)
386                                 goto unlock;
387                         /*
388                          *      POSIX 1003.1g mandates this order.
389                          */
390                         err = sock_error(sk);
391                         if (err)
392                                 goto unlock;
393                         err = -ECONNRESET;
394                         if (sk->sk_shutdown & RCV_SHUTDOWN)
395                                 goto unlock;
396 
397                         err = -EPIPE;
398                         if (sk->sk_state != CAIF_CONNECTED)
399                                 goto unlock;
400                         if (sock_flag(sk, SOCK_DEAD))
401                                 goto unlock;
402 
403                         release_sock(sk);
404 
405                         err = -EAGAIN;
406                         if (!timeo)
407                                 break;
408 
409                         caif_read_unlock(sk);
410 
411                         timeo = caif_stream_data_wait(sk, timeo);
412 
413                         if (signal_pending(current)) {
414                                 err = sock_intr_errno(timeo);
415                                 goto out;
416                         }
417                         caif_read_lock(sk);
418                         continue;
419 unlock:
420                         release_sock(sk);
421                         break;
422                 }
423                 release_sock(sk);
424                 chunk = min_t(unsigned int, skb->len, size);
425                 if (memcpy_to_msg(msg, skb->data, chunk)) {
426                         skb_queue_head(&sk->sk_receive_queue, skb);
427                         if (copied == 0)
428                                 copied = -EFAULT;
429                         break;
430                 }
431                 copied += chunk;
432                 size -= chunk;
433 
434                 /* Mark read part of skb as used */
435                 if (!(flags & MSG_PEEK)) {
436                         skb_pull(skb, chunk);
437 
438                         /* put the skb back if we didn't use it up. */
439                         if (skb->len) {
440                                 skb_queue_head(&sk->sk_receive_queue, skb);
441                                 break;
442                         }
443                         kfree_skb(skb);
444 
445                 } else {
446                         /*
447                          * It is questionable, see note in unix_dgram_recvmsg.
448                          */
449                         /* put message back and return */
450                         skb_queue_head(&sk->sk_receive_queue, skb);
451                         break;
452                 }
453         } while (size);
454         caif_read_unlock(sk);
455 
456 out:
457         return copied ? : err;
458 }
459 
460 /*
461  * Copied from sock.c:sock_wait_for_wmem, but change to wait for
462  * CAIF flow-on and sock_writable.
463  */
464 static long caif_wait_for_flow_on(struct caifsock *cf_sk,
465                                   int wait_writeable, long timeo, int *err)
466 {
467         struct sock *sk = &cf_sk->sk;
468         DEFINE_WAIT(wait);
469         for (;;) {
470                 *err = 0;
471                 if (tx_flow_is_on(cf_sk) &&
472                         (!wait_writeable || sock_writeable(&cf_sk->sk)))
473                         break;
474                 *err = -ETIMEDOUT;
475                 if (!timeo)
476                         break;
477                 *err = -ERESTARTSYS;
478                 if (signal_pending(current))
479                         break;
480                 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
481                 *err = -ECONNRESET;
482                 if (sk->sk_shutdown & SHUTDOWN_MASK)
483                         break;
484                 *err = -sk->sk_err;
485                 if (sk->sk_err)
486                         break;
487                 *err = -EPIPE;
488                 if (cf_sk->sk.sk_state != CAIF_CONNECTED)
489                         break;
490                 timeo = schedule_timeout(timeo);
491         }
492         finish_wait(sk_sleep(sk), &wait);
493         return timeo;
494 }
495 
496 /*
497  * Transmit a SKB. The device may temporarily request re-transmission
498  * by returning EAGAIN.
499  */
500 static int transmit_skb(struct sk_buff *skb, struct caifsock *cf_sk,
501                         int noblock, long timeo)
502 {
503         struct cfpkt *pkt;
504 
505         pkt = cfpkt_fromnative(CAIF_DIR_OUT, skb);
506         memset(skb->cb, 0, sizeof(struct caif_payload_info));
507         cfpkt_set_prio(pkt, cf_sk->sk.sk_priority);
508 
509         if (cf_sk->layer.dn == NULL) {
510                 kfree_skb(skb);
511                 return -EINVAL;
512         }
513 
514         return cf_sk->layer.dn->transmit(cf_sk->layer.dn, pkt);
515 }
516 
517 /* Copied from af_unix:unix_dgram_sendmsg, and adapted to CAIF */
518 static int caif_seqpkt_sendmsg(struct socket *sock, struct msghdr *msg,
519                                size_t len)
520 {
521         struct sock *sk = sock->sk;
522         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
523         int buffer_size;
524         int ret = 0;
525         struct sk_buff *skb = NULL;
526         int noblock;
527         long timeo;
528         caif_assert(cf_sk);
529         ret = sock_error(sk);
530         if (ret)
531                 goto err;
532 
533         ret = -EOPNOTSUPP;
534         if (msg->msg_flags&MSG_OOB)
535                 goto err;
536 
537         ret = -EOPNOTSUPP;
538         if (msg->msg_namelen)
539                 goto err;
540 
541         ret = -EINVAL;
542         if (unlikely(msg->msg_iter.iov->iov_base == NULL))
543                 goto err;
544         noblock = msg->msg_flags & MSG_DONTWAIT;
545 
546         timeo = sock_sndtimeo(sk, noblock);
547         timeo = caif_wait_for_flow_on(container_of(sk, struct caifsock, sk),
548                                 1, timeo, &ret);
549 
550         if (ret)
551                 goto err;
552         ret = -EPIPE;
553         if (cf_sk->sk.sk_state != CAIF_CONNECTED ||
554                 sock_flag(sk, SOCK_DEAD) ||
555                 (sk->sk_shutdown & RCV_SHUTDOWN))
556                 goto err;
557 
558         /* Error if trying to write more than maximum frame size. */
559         ret = -EMSGSIZE;
560         if (len > cf_sk->maxframe && cf_sk->sk.sk_protocol != CAIFPROTO_RFM)
561                 goto err;
562 
563         buffer_size = len + cf_sk->headroom + cf_sk->tailroom;
564 
565         ret = -ENOMEM;
566         skb = sock_alloc_send_skb(sk, buffer_size, noblock, &ret);
567 
568         if (!skb || skb_tailroom(skb) < buffer_size)
569                 goto err;
570 
571         skb_reserve(skb, cf_sk->headroom);
572 
573         ret = memcpy_from_msg(skb_put(skb, len), msg, len);
574 
575         if (ret)
576                 goto err;
577         ret = transmit_skb(skb, cf_sk, noblock, timeo);
578         if (ret < 0)
579                 /* skb is already freed */
580                 return ret;
581 
582         return len;
583 err:
584         kfree_skb(skb);
585         return ret;
586 }
587 
588 /*
589  * Copied from unix_stream_sendmsg and adapted to CAIF:
590  * Changed removed permission handling and added waiting for flow on
591  * and other minor adaptations.
592  */
593 static int caif_stream_sendmsg(struct socket *sock, struct msghdr *msg,
594                                size_t len)
595 {
596         struct sock *sk = sock->sk;
597         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
598         int err, size;
599         struct sk_buff *skb;
600         int sent = 0;
601         long timeo;
602 
603         err = -EOPNOTSUPP;
604         if (unlikely(msg->msg_flags&MSG_OOB))
605                 goto out_err;
606 
607         if (unlikely(msg->msg_namelen))
608                 goto out_err;
609 
610         timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
611         timeo = caif_wait_for_flow_on(cf_sk, 1, timeo, &err);
612 
613         if (unlikely(sk->sk_shutdown & SEND_SHUTDOWN))
614                 goto pipe_err;
615 
616         while (sent < len) {
617 
618                 size = len-sent;
619 
620                 if (size > cf_sk->maxframe)
621                         size = cf_sk->maxframe;
622 
623                 /* If size is more than half of sndbuf, chop up message */
624                 if (size > ((sk->sk_sndbuf >> 1) - 64))
625                         size = (sk->sk_sndbuf >> 1) - 64;
626 
627                 if (size > SKB_MAX_ALLOC)
628                         size = SKB_MAX_ALLOC;
629 
630                 skb = sock_alloc_send_skb(sk,
631                                         size + cf_sk->headroom +
632                                         cf_sk->tailroom,
633                                         msg->msg_flags&MSG_DONTWAIT,
634                                         &err);
635                 if (skb == NULL)
636                         goto out_err;
637 
638                 skb_reserve(skb, cf_sk->headroom);
639                 /*
640                  *      If you pass two values to the sock_alloc_send_skb
641                  *      it tries to grab the large buffer with GFP_NOFS
642                  *      (which can fail easily), and if it fails grab the
643                  *      fallback size buffer which is under a page and will
644                  *      succeed. [Alan]
645                  */
646                 size = min_t(int, size, skb_tailroom(skb));
647 
648                 err = memcpy_from_msg(skb_put(skb, size), msg, size);
649                 if (err) {
650                         kfree_skb(skb);
651                         goto out_err;
652                 }
653                 err = transmit_skb(skb, cf_sk,
654                                 msg->msg_flags&MSG_DONTWAIT, timeo);
655                 if (err < 0)
656                         /* skb is already freed */
657                         goto pipe_err;
658 
659                 sent += size;
660         }
661 
662         return sent;
663 
664 pipe_err:
665         if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
666                 send_sig(SIGPIPE, current, 0);
667         err = -EPIPE;
668 out_err:
669         return sent ? : err;
670 }
671 
672 static int setsockopt(struct socket *sock,
673                       int lvl, int opt, char __user *ov, unsigned int ol)
674 {
675         struct sock *sk = sock->sk;
676         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
677         int linksel;
678 
679         if (cf_sk->sk.sk_socket->state != SS_UNCONNECTED)
680                 return -ENOPROTOOPT;
681 
682         switch (opt) {
683         case CAIFSO_LINK_SELECT:
684                 if (ol < sizeof(int))
685                         return -EINVAL;
686                 if (lvl != SOL_CAIF)
687                         goto bad_sol;
688                 if (copy_from_user(&linksel, ov, sizeof(int)))
689                         return -EINVAL;
690                 lock_sock(&(cf_sk->sk));
691                 cf_sk->conn_req.link_selector = linksel;
692                 release_sock(&cf_sk->sk);
693                 return 0;
694 
695         case CAIFSO_REQ_PARAM:
696                 if (lvl != SOL_CAIF)
697                         goto bad_sol;
698                 if (cf_sk->sk.sk_protocol != CAIFPROTO_UTIL)
699                         return -ENOPROTOOPT;
700                 lock_sock(&(cf_sk->sk));
701                 if (ol > sizeof(cf_sk->conn_req.param.data) ||
702                         copy_from_user(&cf_sk->conn_req.param.data, ov, ol)) {
703                         release_sock(&cf_sk->sk);
704                         return -EINVAL;
705                 }
706                 cf_sk->conn_req.param.size = ol;
707                 release_sock(&cf_sk->sk);
708                 return 0;
709 
710         default:
711                 return -ENOPROTOOPT;
712         }
713 
714         return 0;
715 bad_sol:
716         return -ENOPROTOOPT;
717 
718 }
719 
720 /*
721  * caif_connect() - Connect a CAIF Socket
722  * Copied and modified af_irda.c:irda_connect().
723  *
724  * Note : by consulting "errno", the user space caller may learn the cause
725  * of the failure. Most of them are visible in the function, others may come
726  * from subroutines called and are listed here :
727  *  o -EAFNOSUPPORT: bad socket family or type.
728  *  o -ESOCKTNOSUPPORT: bad socket type or protocol
729  *  o -EINVAL: bad socket address, or CAIF link type
730  *  o -ECONNREFUSED: remote end refused the connection.
731  *  o -EINPROGRESS: connect request sent but timed out (or non-blocking)
732  *  o -EISCONN: already connected.
733  *  o -ETIMEDOUT: Connection timed out (send timeout)
734  *  o -ENODEV: No link layer to send request
735  *  o -ECONNRESET: Received Shutdown indication or lost link layer
736  *  o -ENOMEM: Out of memory
737  *
738  *  State Strategy:
739  *  o sk_state: holds the CAIF_* protocol state, it's updated by
740  *      caif_ctrl_cb.
741  *  o sock->state: holds the SS_* socket state and is updated by connect and
742  *      disconnect.
743  */
744 static int caif_connect(struct socket *sock, struct sockaddr *uaddr,
745                         int addr_len, int flags)
746 {
747         struct sock *sk = sock->sk;
748         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
749         long timeo;
750         int err;
751         int ifindex, headroom, tailroom;
752         unsigned int mtu;
753         struct net_device *dev;
754 
755         lock_sock(sk);
756 
757         err = -EAFNOSUPPORT;
758         if (uaddr->sa_family != AF_CAIF)
759                 goto out;
760 
761         switch (sock->state) {
762         case SS_UNCONNECTED:
763                 /* Normal case, a fresh connect */
764                 caif_assert(sk->sk_state == CAIF_DISCONNECTED);
765                 break;
766         case SS_CONNECTING:
767                 switch (sk->sk_state) {
768                 case CAIF_CONNECTED:
769                         sock->state = SS_CONNECTED;
770                         err = -EISCONN;
771                         goto out;
772                 case CAIF_DISCONNECTED:
773                         /* Reconnect allowed */
774                         break;
775                 case CAIF_CONNECTING:
776                         err = -EALREADY;
777                         if (flags & O_NONBLOCK)
778                                 goto out;
779                         goto wait_connect;
780                 }
781                 break;
782         case SS_CONNECTED:
783                 caif_assert(sk->sk_state == CAIF_CONNECTED ||
784                                 sk->sk_state == CAIF_DISCONNECTED);
785                 if (sk->sk_shutdown & SHUTDOWN_MASK) {
786                         /* Allow re-connect after SHUTDOWN_IND */
787                         caif_disconnect_client(sock_net(sk), &cf_sk->layer);
788                         caif_free_client(&cf_sk->layer);
789                         break;
790                 }
791                 /* No reconnect on a seqpacket socket */
792                 err = -EISCONN;
793                 goto out;
794         case SS_DISCONNECTING:
795         case SS_FREE:
796                 caif_assert(1); /*Should never happen */
797                 break;
798         }
799         sk->sk_state = CAIF_DISCONNECTED;
800         sock->state = SS_UNCONNECTED;
801         sk_stream_kill_queues(&cf_sk->sk);
802 
803         err = -EINVAL;
804         if (addr_len != sizeof(struct sockaddr_caif))
805                 goto out;
806 
807         memcpy(&cf_sk->conn_req.sockaddr, uaddr,
808                 sizeof(struct sockaddr_caif));
809 
810         /* Move to connecting socket, start sending Connect Requests */
811         sock->state = SS_CONNECTING;
812         sk->sk_state = CAIF_CONNECTING;
813 
814         /* Check priority value comming from socket */
815         /* if priority value is out of range it will be ajusted */
816         if (cf_sk->sk.sk_priority > CAIF_PRIO_MAX)
817                 cf_sk->conn_req.priority = CAIF_PRIO_MAX;
818         else if (cf_sk->sk.sk_priority < CAIF_PRIO_MIN)
819                 cf_sk->conn_req.priority = CAIF_PRIO_MIN;
820         else
821                 cf_sk->conn_req.priority = cf_sk->sk.sk_priority;
822 
823         /*ifindex = id of the interface.*/
824         cf_sk->conn_req.ifindex = cf_sk->sk.sk_bound_dev_if;
825 
826         cf_sk->layer.receive = caif_sktrecv_cb;
827 
828         err = caif_connect_client(sock_net(sk), &cf_sk->conn_req,
829                                 &cf_sk->layer, &ifindex, &headroom, &tailroom);
830 
831         if (err < 0) {
832                 cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
833                 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
834                 goto out;
835         }
836 
837         err = -ENODEV;
838         rcu_read_lock();
839         dev = dev_get_by_index_rcu(sock_net(sk), ifindex);
840         if (!dev) {
841                 rcu_read_unlock();
842                 goto out;
843         }
844         cf_sk->headroom = LL_RESERVED_SPACE_EXTRA(dev, headroom);
845         mtu = dev->mtu;
846         rcu_read_unlock();
847 
848         cf_sk->tailroom = tailroom;
849         cf_sk->maxframe = mtu - (headroom + tailroom);
850         if (cf_sk->maxframe < 1) {
851                 pr_warn("CAIF Interface MTU too small (%d)\n", dev->mtu);
852                 err = -ENODEV;
853                 goto out;
854         }
855 
856         err = -EINPROGRESS;
857 wait_connect:
858 
859         if (sk->sk_state != CAIF_CONNECTED && (flags & O_NONBLOCK))
860                 goto out;
861 
862         timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
863 
864         release_sock(sk);
865         err = -ERESTARTSYS;
866         timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
867                         sk->sk_state != CAIF_CONNECTING,
868                         timeo);
869         lock_sock(sk);
870         if (timeo < 0)
871                 goto out; /* -ERESTARTSYS */
872 
873         err = -ETIMEDOUT;
874         if (timeo == 0 && sk->sk_state != CAIF_CONNECTED)
875                 goto out;
876         if (sk->sk_state != CAIF_CONNECTED) {
877                 sock->state = SS_UNCONNECTED;
878                 err = sock_error(sk);
879                 if (!err)
880                         err = -ECONNREFUSED;
881                 goto out;
882         }
883         sock->state = SS_CONNECTED;
884         err = 0;
885 out:
886         release_sock(sk);
887         return err;
888 }
889 
890 /*
891  * caif_release() - Disconnect a CAIF Socket
892  * Copied and modified af_irda.c:irda_release().
893  */
894 static int caif_release(struct socket *sock)
895 {
896         struct sock *sk = sock->sk;
897         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
898 
899         if (!sk)
900                 return 0;
901 
902         set_tx_flow_off(cf_sk);
903 
904         /*
905          * Ensure that packets are not queued after this point in time.
906          * caif_queue_rcv_skb checks SOCK_DEAD holding the queue lock,
907          * this ensures no packets when sock is dead.
908          */
909         spin_lock_bh(&sk->sk_receive_queue.lock);
910         sock_set_flag(sk, SOCK_DEAD);
911         spin_unlock_bh(&sk->sk_receive_queue.lock);
912         sock->sk = NULL;
913 
914         WARN_ON(IS_ERR(cf_sk->debugfs_socket_dir));
915         debugfs_remove_recursive(cf_sk->debugfs_socket_dir);
916 
917         lock_sock(&(cf_sk->sk));
918         sk->sk_state = CAIF_DISCONNECTED;
919         sk->sk_shutdown = SHUTDOWN_MASK;
920 
921         caif_disconnect_client(sock_net(sk), &cf_sk->layer);
922         cf_sk->sk.sk_socket->state = SS_DISCONNECTING;
923         wake_up_interruptible_poll(sk_sleep(sk), POLLERR|POLLHUP);
924 
925         sock_orphan(sk);
926         sk_stream_kill_queues(&cf_sk->sk);
927         release_sock(sk);
928         sock_put(sk);
929         return 0;
930 }
931 
932 /* Copied from af_unix.c:unix_poll(), added CAIF tx_flow handling */
933 static unsigned int caif_poll(struct file *file,
934                               struct socket *sock, poll_table *wait)
935 {
936         struct sock *sk = sock->sk;
937         unsigned int mask;
938         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
939 
940         sock_poll_wait(file, sk_sleep(sk), wait);
941         mask = 0;
942 
943         /* exceptional events? */
944         if (sk->sk_err)
945                 mask |= POLLERR;
946         if (sk->sk_shutdown == SHUTDOWN_MASK)
947                 mask |= POLLHUP;
948         if (sk->sk_shutdown & RCV_SHUTDOWN)
949                 mask |= POLLRDHUP;
950 
951         /* readable? */
952         if (!skb_queue_empty(&sk->sk_receive_queue) ||
953                 (sk->sk_shutdown & RCV_SHUTDOWN))
954                 mask |= POLLIN | POLLRDNORM;
955 
956         /*
957          * we set writable also when the other side has shut down the
958          * connection. This prevents stuck sockets.
959          */
960         if (sock_writeable(sk) && tx_flow_is_on(cf_sk))
961                 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
962 
963         return mask;
964 }
965 
966 static const struct proto_ops caif_seqpacket_ops = {
967         .family = PF_CAIF,
968         .owner = THIS_MODULE,
969         .release = caif_release,
970         .bind = sock_no_bind,
971         .connect = caif_connect,
972         .socketpair = sock_no_socketpair,
973         .accept = sock_no_accept,
974         .getname = sock_no_getname,
975         .poll = caif_poll,
976         .ioctl = sock_no_ioctl,
977         .listen = sock_no_listen,
978         .shutdown = sock_no_shutdown,
979         .setsockopt = setsockopt,
980         .getsockopt = sock_no_getsockopt,
981         .sendmsg = caif_seqpkt_sendmsg,
982         .recvmsg = caif_seqpkt_recvmsg,
983         .mmap = sock_no_mmap,
984         .sendpage = sock_no_sendpage,
985 };
986 
987 static const struct proto_ops caif_stream_ops = {
988         .family = PF_CAIF,
989         .owner = THIS_MODULE,
990         .release = caif_release,
991         .bind = sock_no_bind,
992         .connect = caif_connect,
993         .socketpair = sock_no_socketpair,
994         .accept = sock_no_accept,
995         .getname = sock_no_getname,
996         .poll = caif_poll,
997         .ioctl = sock_no_ioctl,
998         .listen = sock_no_listen,
999         .shutdown = sock_no_shutdown,
1000         .setsockopt = setsockopt,
1001         .getsockopt = sock_no_getsockopt,
1002         .sendmsg = caif_stream_sendmsg,
1003         .recvmsg = caif_stream_recvmsg,
1004         .mmap = sock_no_mmap,
1005         .sendpage = sock_no_sendpage,
1006 };
1007 
1008 /* This function is called when a socket is finally destroyed. */
1009 static void caif_sock_destructor(struct sock *sk)
1010 {
1011         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
1012         caif_assert(!atomic_read(&sk->sk_wmem_alloc));
1013         caif_assert(sk_unhashed(sk));
1014         caif_assert(!sk->sk_socket);
1015         if (!sock_flag(sk, SOCK_DEAD)) {
1016                 pr_debug("Attempt to release alive CAIF socket: %p\n", sk);
1017                 return;
1018         }
1019         sk_stream_kill_queues(&cf_sk->sk);
1020         caif_free_client(&cf_sk->layer);
1021 }
1022 
1023 static int caif_create(struct net *net, struct socket *sock, int protocol,
1024                        int kern)
1025 {
1026         struct sock *sk = NULL;
1027         struct caifsock *cf_sk = NULL;
1028         static struct proto prot = {.name = "PF_CAIF",
1029                 .owner = THIS_MODULE,
1030                 .obj_size = sizeof(struct caifsock),
1031         };
1032 
1033         if (!capable(CAP_SYS_ADMIN) && !capable(CAP_NET_ADMIN))
1034                 return -EPERM;
1035         /*
1036          * The sock->type specifies the socket type to use.
1037          * The CAIF socket is a packet stream in the sense
1038          * that it is packet based. CAIF trusts the reliability
1039          * of the link, no resending is implemented.
1040          */
1041         if (sock->type == SOCK_SEQPACKET)
1042                 sock->ops = &caif_seqpacket_ops;
1043         else if (sock->type == SOCK_STREAM)
1044                 sock->ops = &caif_stream_ops;
1045         else
1046                 return -ESOCKTNOSUPPORT;
1047 
1048         if (protocol < 0 || protocol >= CAIFPROTO_MAX)
1049                 return -EPROTONOSUPPORT;
1050         /*
1051          * Set the socket state to unconnected.  The socket state
1052          * is really not used at all in the net/core or socket.c but the
1053          * initialization makes sure that sock->state is not uninitialized.
1054          */
1055         sk = sk_alloc(net, PF_CAIF, GFP_KERNEL, &prot, kern);
1056         if (!sk)
1057                 return -ENOMEM;
1058 
1059         cf_sk = container_of(sk, struct caifsock, sk);
1060 
1061         /* Store the protocol */
1062         sk->sk_protocol = (unsigned char) protocol;
1063 
1064         /* Initialize default priority for well-known cases */
1065         switch (protocol) {
1066         case CAIFPROTO_AT:
1067                 sk->sk_priority = TC_PRIO_CONTROL;
1068                 break;
1069         case CAIFPROTO_RFM:
1070                 sk->sk_priority = TC_PRIO_INTERACTIVE_BULK;
1071                 break;
1072         default:
1073                 sk->sk_priority = TC_PRIO_BESTEFFORT;
1074         }
1075 
1076         /*
1077          * Lock in order to try to stop someone from opening the socket
1078          * too early.
1079          */
1080         lock_sock(&(cf_sk->sk));
1081 
1082         /* Initialize the nozero default sock structure data. */
1083         sock_init_data(sock, sk);
1084         sk->sk_destruct = caif_sock_destructor;
1085 
1086         mutex_init(&cf_sk->readlock); /* single task reading lock */
1087         cf_sk->layer.ctrlcmd = caif_ctrl_cb;
1088         cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
1089         cf_sk->sk.sk_state = CAIF_DISCONNECTED;
1090 
1091         set_tx_flow_off(cf_sk);
1092         set_rx_flow_on(cf_sk);
1093 
1094         /* Set default options on configuration */
1095         cf_sk->conn_req.link_selector = CAIF_LINK_LOW_LATENCY;
1096         cf_sk->conn_req.protocol = protocol;
1097         release_sock(&cf_sk->sk);
1098         return 0;
1099 }
1100 
1101 
1102 static struct net_proto_family caif_family_ops = {
1103         .family = PF_CAIF,
1104         .create = caif_create,
1105         .owner = THIS_MODULE,
1106 };
1107 
1108 static int __init caif_sktinit_module(void)
1109 {
1110         int err = sock_register(&caif_family_ops);
1111         if (!err)
1112                 return err;
1113         return 0;
1114 }
1115 
1116 static void __exit caif_sktexit_module(void)
1117 {
1118         sock_unregister(PF_CAIF);
1119 }
1120 module_init(caif_sktinit_module);
1121 module_exit(caif_sktexit_module);
1122 

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us