caif: Don't resend if dev_queue_xmit fails.
[linux-2.6.git] / net / caif / caif_socket.c
1 /*
2  * Copyright (C) ST-Ericsson AB 2010
3  * Author:      Sjur Brendeland sjur.brandeland@stericsson.com
4  * License terms: GNU General Public License (GPL) version 2
5  */
6
7 #define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
8
9 #include <linux/fs.h>
10 #include <linux/init.h>
11 #include <linux/module.h>
12 #include <linux/sched.h>
13 #include <linux/spinlock.h>
14 #include <linux/mutex.h>
15 #include <linux/list.h>
16 #include <linux/wait.h>
17 #include <linux/poll.h>
18 #include <linux/tcp.h>
19 #include <linux/uaccess.h>
20 #include <linux/debugfs.h>
21 #include <linux/caif/caif_socket.h>
22 #include <asm/atomic.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 static struct dentry *debugfsdir;
47
48 #ifdef CONFIG_DEBUG_FS
49 struct debug_fs_counter {
50         atomic_t caif_nr_socks;
51         atomic_t num_connect_req;
52         atomic_t num_connect_resp;
53         atomic_t num_connect_fail_resp;
54         atomic_t num_disconnect;
55         atomic_t num_remote_shutdown_ind;
56         atomic_t num_tx_flow_off_ind;
57         atomic_t num_tx_flow_on_ind;
58         atomic_t num_rx_flow_off;
59         atomic_t num_rx_flow_on;
60 };
61 static struct debug_fs_counter cnt;
62 #define dbfs_atomic_inc(v) atomic_inc(v)
63 #define dbfs_atomic_dec(v) atomic_dec(v)
64 #else
65 #define dbfs_atomic_inc(v)
66 #define dbfs_atomic_dec(v)
67 #endif
68
69 struct caifsock {
70         struct sock sk; /* must be first member */
71         struct cflayer layer;
72         char name[CAIF_LAYER_NAME_SZ]; /* Used for debugging */
73         u32 flow_state;
74         struct caif_connect_request conn_req;
75         struct mutex readlock;
76         struct dentry *debugfs_socket_dir;
77         int headroom, tailroom, maxframe;
78 };
79
80 static int rx_flow_is_on(struct caifsock *cf_sk)
81 {
82         return test_bit(RX_FLOW_ON_BIT,
83                         (void *) &cf_sk->flow_state);
84 }
85
86 static int tx_flow_is_on(struct caifsock *cf_sk)
87 {
88         return test_bit(TX_FLOW_ON_BIT,
89                         (void *) &cf_sk->flow_state);
90 }
91
92 static void set_rx_flow_off(struct caifsock *cf_sk)
93 {
94          clear_bit(RX_FLOW_ON_BIT,
95                  (void *) &cf_sk->flow_state);
96 }
97
98 static void set_rx_flow_on(struct caifsock *cf_sk)
99 {
100          set_bit(RX_FLOW_ON_BIT,
101                         (void *) &cf_sk->flow_state);
102 }
103
104 static void set_tx_flow_off(struct caifsock *cf_sk)
105 {
106          clear_bit(TX_FLOW_ON_BIT,
107                 (void *) &cf_sk->flow_state);
108 }
109
110 static void set_tx_flow_on(struct caifsock *cf_sk)
111 {
112          set_bit(TX_FLOW_ON_BIT,
113                 (void *) &cf_sk->flow_state);
114 }
115
116 static void caif_read_lock(struct sock *sk)
117 {
118         struct caifsock *cf_sk;
119         cf_sk = container_of(sk, struct caifsock, sk);
120         mutex_lock(&cf_sk->readlock);
121 }
122
123 static void caif_read_unlock(struct sock *sk)
124 {
125         struct caifsock *cf_sk;
126         cf_sk = container_of(sk, struct caifsock, sk);
127         mutex_unlock(&cf_sk->readlock);
128 }
129
130 static int sk_rcvbuf_lowwater(struct caifsock *cf_sk)
131 {
132         /* A quarter of full buffer is used a low water mark */
133         return cf_sk->sk.sk_rcvbuf / 4;
134 }
135
136 static void caif_flow_ctrl(struct sock *sk, int mode)
137 {
138         struct caifsock *cf_sk;
139         cf_sk = container_of(sk, struct caifsock, sk);
140         if (cf_sk->layer.dn && cf_sk->layer.dn->modemcmd)
141                 cf_sk->layer.dn->modemcmd(cf_sk->layer.dn, mode);
142 }
143
144 /*
145  * Copied from sock.c:sock_queue_rcv_skb(), but changed so packets are
146  * not dropped, but CAIF is sending flow off instead.
147  */
148 static int caif_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
149 {
150         int err;
151         int skb_len;
152         unsigned long flags;
153         struct sk_buff_head *list = &sk->sk_receive_queue;
154         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
155
156         if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
157                 (unsigned)sk->sk_rcvbuf && rx_flow_is_on(cf_sk)) {
158                 pr_debug("sending flow OFF (queue len = %d %d)\n",
159                         atomic_read(&cf_sk->sk.sk_rmem_alloc),
160                         sk_rcvbuf_lowwater(cf_sk));
161                 set_rx_flow_off(cf_sk);
162                 dbfs_atomic_inc(&cnt.num_rx_flow_off);
163                 caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ);
164         }
165
166         err = sk_filter(sk, skb);
167         if (err)
168                 return err;
169         if (!sk_rmem_schedule(sk, skb->truesize) && rx_flow_is_on(cf_sk)) {
170                 set_rx_flow_off(cf_sk);
171                 pr_debug("sending flow OFF due to rmem_schedule\n");
172                 dbfs_atomic_inc(&cnt.num_rx_flow_off);
173                 caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ);
174         }
175         skb->dev = NULL;
176         skb_set_owner_r(skb, sk);
177         /* Cache the SKB length before we tack it onto the receive
178          * queue. Once it is added it no longer belongs to us and
179          * may be freed by other threads of control pulling packets
180          * from the queue.
181          */
182         skb_len = skb->len;
183         spin_lock_irqsave(&list->lock, flags);
184         if (!sock_flag(sk, SOCK_DEAD))
185                 __skb_queue_tail(list, skb);
186         spin_unlock_irqrestore(&list->lock, flags);
187
188         if (!sock_flag(sk, SOCK_DEAD))
189                 sk->sk_data_ready(sk, skb_len);
190         else
191                 kfree_skb(skb);
192         return 0;
193 }
194
195 /* Packet Receive Callback function called from CAIF Stack */
196 static int caif_sktrecv_cb(struct cflayer *layr, struct cfpkt *pkt)
197 {
198         struct caifsock *cf_sk;
199         struct sk_buff *skb;
200
201         cf_sk = container_of(layr, struct caifsock, layer);
202         skb = cfpkt_tonative(pkt);
203
204         if (unlikely(cf_sk->sk.sk_state != CAIF_CONNECTED)) {
205                 cfpkt_destroy(pkt);
206                 return 0;
207         }
208         caif_queue_rcv_skb(&cf_sk->sk, skb);
209         return 0;
210 }
211
212 /* Packet Control Callback function called from CAIF */
213 static void caif_ctrl_cb(struct cflayer *layr,
214                                 enum caif_ctrlcmd flow,
215                                 int phyid)
216 {
217         struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
218         switch (flow) {
219         case CAIF_CTRLCMD_FLOW_ON_IND:
220                 /* OK from modem to start sending again */
221                 dbfs_atomic_inc(&cnt.num_tx_flow_on_ind);
222                 set_tx_flow_on(cf_sk);
223                 cf_sk->sk.sk_state_change(&cf_sk->sk);
224                 break;
225
226         case CAIF_CTRLCMD_FLOW_OFF_IND:
227                 /* Modem asks us to shut up */
228                 dbfs_atomic_inc(&cnt.num_tx_flow_off_ind);
229                 set_tx_flow_off(cf_sk);
230                 cf_sk->sk.sk_state_change(&cf_sk->sk);
231                 break;
232
233         case CAIF_CTRLCMD_INIT_RSP:
234                 /* We're now connected */
235                 dbfs_atomic_inc(&cnt.num_connect_resp);
236                 cf_sk->sk.sk_state = CAIF_CONNECTED;
237                 set_tx_flow_on(cf_sk);
238                 cf_sk->sk.sk_state_change(&cf_sk->sk);
239                 break;
240
241         case CAIF_CTRLCMD_DEINIT_RSP:
242                 /* We're now disconnected */
243                 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
244                 cf_sk->sk.sk_state_change(&cf_sk->sk);
245                 cfcnfg_release_adap_layer(&cf_sk->layer);
246                 break;
247
248         case CAIF_CTRLCMD_INIT_FAIL_RSP:
249                 /* Connect request failed */
250                 dbfs_atomic_inc(&cnt.num_connect_fail_resp);
251                 cf_sk->sk.sk_err = ECONNREFUSED;
252                 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
253                 cf_sk->sk.sk_shutdown = SHUTDOWN_MASK;
254                 /*
255                  * Socket "standards" seems to require POLLOUT to
256                  * be set at connect failure.
257                  */
258                 set_tx_flow_on(cf_sk);
259                 cf_sk->sk.sk_state_change(&cf_sk->sk);
260                 break;
261
262         case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
263                 /* Modem has closed this connection, or device is down. */
264                 dbfs_atomic_inc(&cnt.num_remote_shutdown_ind);
265                 cf_sk->sk.sk_shutdown = SHUTDOWN_MASK;
266                 cf_sk->sk.sk_err = ECONNRESET;
267                 set_rx_flow_on(cf_sk);
268                 cf_sk->sk.sk_error_report(&cf_sk->sk);
269                 break;
270
271         default:
272                 pr_debug("Unexpected flow command %d\n", flow);
273         }
274 }
275
276 static void caif_check_flow_release(struct sock *sk)
277 {
278         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
279
280         if (rx_flow_is_on(cf_sk))
281                 return;
282
283         if (atomic_read(&sk->sk_rmem_alloc) <= sk_rcvbuf_lowwater(cf_sk)) {
284                         dbfs_atomic_inc(&cnt.num_rx_flow_on);
285                         set_rx_flow_on(cf_sk);
286                         caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_ON_REQ);
287         }
288 }
289
290 /*
291  * Copied from unix_dgram_recvmsg, but removed credit checks,
292  * changed locking, address handling and added MSG_TRUNC.
293  */
294 static int caif_seqpkt_recvmsg(struct kiocb *iocb, struct socket *sock,
295                                 struct msghdr *m, size_t len, int flags)
296
297 {
298         struct sock *sk = sock->sk;
299         struct sk_buff *skb;
300         int ret;
301         int copylen;
302
303         ret = -EOPNOTSUPP;
304         if (m->msg_flags&MSG_OOB)
305                 goto read_error;
306
307         skb = skb_recv_datagram(sk, flags, 0 , &ret);
308         if (!skb)
309                 goto read_error;
310         copylen = skb->len;
311         if (len < copylen) {
312                 m->msg_flags |= MSG_TRUNC;
313                 copylen = len;
314         }
315
316         ret = skb_copy_datagram_iovec(skb, 0, m->msg_iov, copylen);
317         if (ret)
318                 goto out_free;
319
320         ret = (flags & MSG_TRUNC) ? skb->len : copylen;
321 out_free:
322         skb_free_datagram(sk, skb);
323         caif_check_flow_release(sk);
324         return ret;
325
326 read_error:
327         return ret;
328 }
329
330
331 /* Copied from unix_stream_wait_data, identical except for lock call. */
332 static long caif_stream_data_wait(struct sock *sk, long timeo)
333 {
334         DEFINE_WAIT(wait);
335         lock_sock(sk);
336
337         for (;;) {
338                 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
339
340                 if (!skb_queue_empty(&sk->sk_receive_queue) ||
341                         sk->sk_err ||
342                         sk->sk_state != CAIF_CONNECTED ||
343                         sock_flag(sk, SOCK_DEAD) ||
344                         (sk->sk_shutdown & RCV_SHUTDOWN) ||
345                         signal_pending(current) ||
346                         !timeo)
347                         break;
348
349                 set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
350                 release_sock(sk);
351                 timeo = schedule_timeout(timeo);
352                 lock_sock(sk);
353                 clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
354         }
355
356         finish_wait(sk_sleep(sk), &wait);
357         release_sock(sk);
358         return timeo;
359 }
360
361
362 /*
363  * Copied from unix_stream_recvmsg, but removed credit checks,
364  * changed locking calls, changed address handling.
365  */
366 static int caif_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
367                                 struct msghdr *msg, size_t size,
368                                 int flags)
369 {
370         struct sock *sk = sock->sk;
371         int copied = 0;
372         int target;
373         int err = 0;
374         long timeo;
375
376         err = -EOPNOTSUPP;
377         if (flags&MSG_OOB)
378                 goto out;
379
380         msg->msg_namelen = 0;
381
382         /*
383          * Lock the socket to prevent queue disordering
384          * while sleeps in memcpy_tomsg
385          */
386         err = -EAGAIN;
387         if (sk->sk_state == CAIF_CONNECTING)
388                 goto out;
389
390         caif_read_lock(sk);
391         target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
392         timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT);
393
394         do {
395                 int chunk;
396                 struct sk_buff *skb;
397
398                 lock_sock(sk);
399                 skb = skb_dequeue(&sk->sk_receive_queue);
400                 caif_check_flow_release(sk);
401
402                 if (skb == NULL) {
403                         if (copied >= target)
404                                 goto unlock;
405                         /*
406                          *      POSIX 1003.1g mandates this order.
407                          */
408                         err = sock_error(sk);
409                         if (err)
410                                 goto unlock;
411                         err = -ECONNRESET;
412                         if (sk->sk_shutdown & RCV_SHUTDOWN)
413                                 goto unlock;
414
415                         err = -EPIPE;
416                         if (sk->sk_state != CAIF_CONNECTED)
417                                 goto unlock;
418                         if (sock_flag(sk, SOCK_DEAD))
419                                 goto unlock;
420
421                         release_sock(sk);
422
423                         err = -EAGAIN;
424                         if (!timeo)
425                                 break;
426
427                         caif_read_unlock(sk);
428
429                         timeo = caif_stream_data_wait(sk, timeo);
430
431                         if (signal_pending(current)) {
432                                 err = sock_intr_errno(timeo);
433                                 goto out;
434                         }
435                         caif_read_lock(sk);
436                         continue;
437 unlock:
438                         release_sock(sk);
439                         break;
440                 }
441                 release_sock(sk);
442                 chunk = min_t(unsigned int, skb->len, size);
443                 if (memcpy_toiovec(msg->msg_iov, skb->data, chunk)) {
444                         skb_queue_head(&sk->sk_receive_queue, skb);
445                         if (copied == 0)
446                                 copied = -EFAULT;
447                         break;
448                 }
449                 copied += chunk;
450                 size -= chunk;
451
452                 /* Mark read part of skb as used */
453                 if (!(flags & MSG_PEEK)) {
454                         skb_pull(skb, chunk);
455
456                         /* put the skb back if we didn't use it up. */
457                         if (skb->len) {
458                                 skb_queue_head(&sk->sk_receive_queue, skb);
459                                 break;
460                         }
461                         kfree_skb(skb);
462
463                 } else {
464                         /*
465                          * It is questionable, see note in unix_dgram_recvmsg.
466                          */
467                         /* put message back and return */
468                         skb_queue_head(&sk->sk_receive_queue, skb);
469                         break;
470                 }
471         } while (size);
472         caif_read_unlock(sk);
473
474 out:
475         return copied ? : err;
476 }
477
478 /*
479  * Copied from sock.c:sock_wait_for_wmem, but change to wait for
480  * CAIF flow-on and sock_writable.
481  */
482 static long caif_wait_for_flow_on(struct caifsock *cf_sk,
483                                 int wait_writeable, long timeo, int *err)
484 {
485         struct sock *sk = &cf_sk->sk;
486         DEFINE_WAIT(wait);
487         for (;;) {
488                 *err = 0;
489                 if (tx_flow_is_on(cf_sk) &&
490                         (!wait_writeable || sock_writeable(&cf_sk->sk)))
491                         break;
492                 *err = -ETIMEDOUT;
493                 if (!timeo)
494                         break;
495                 *err = -ERESTARTSYS;
496                 if (signal_pending(current))
497                         break;
498                 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
499                 *err = -ECONNRESET;
500                 if (sk->sk_shutdown & SHUTDOWN_MASK)
501                         break;
502                 *err = -sk->sk_err;
503                 if (sk->sk_err)
504                         break;
505                 *err = -EPIPE;
506                 if (cf_sk->sk.sk_state != CAIF_CONNECTED)
507                         break;
508                 timeo = schedule_timeout(timeo);
509         }
510         finish_wait(sk_sleep(sk), &wait);
511         return timeo;
512 }
513
514 /*
515  * Transmit a SKB. The device may temporarily request re-transmission
516  * by returning EAGAIN.
517  */
518 static int transmit_skb(struct sk_buff *skb, struct caifsock *cf_sk,
519                         int noblock, long timeo)
520 {
521         struct cfpkt *pkt;
522
523         pkt = cfpkt_fromnative(CAIF_DIR_OUT, skb);
524         memset(cfpkt_info(pkt), 0, sizeof(struct caif_payload_info));
525
526         if (cf_sk->layer.dn == NULL)
527                 return -EINVAL;
528
529         return cf_sk->layer.dn->transmit(cf_sk->layer.dn, pkt);
530 }
531
532 /* Copied from af_unix:unix_dgram_sendmsg, and adapted to CAIF */
533 static int caif_seqpkt_sendmsg(struct kiocb *kiocb, struct socket *sock,
534                         struct msghdr *msg, size_t len)
535 {
536         struct sock *sk = sock->sk;
537         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
538         int buffer_size;
539         int ret = 0;
540         struct sk_buff *skb = NULL;
541         int noblock;
542         long timeo;
543         caif_assert(cf_sk);
544         ret = sock_error(sk);
545         if (ret)
546                 goto err;
547
548         ret = -EOPNOTSUPP;
549         if (msg->msg_flags&MSG_OOB)
550                 goto err;
551
552         ret = -EOPNOTSUPP;
553         if (msg->msg_namelen)
554                 goto err;
555
556         ret = -EINVAL;
557         if (unlikely(msg->msg_iov->iov_base == NULL))
558                 goto err;
559         noblock = msg->msg_flags & MSG_DONTWAIT;
560
561         timeo = sock_sndtimeo(sk, noblock);
562         timeo = caif_wait_for_flow_on(container_of(sk, struct caifsock, sk),
563                                 1, timeo, &ret);
564
565         if (ret)
566                 goto err;
567         ret = -EPIPE;
568         if (cf_sk->sk.sk_state != CAIF_CONNECTED ||
569                 sock_flag(sk, SOCK_DEAD) ||
570                 (sk->sk_shutdown & RCV_SHUTDOWN))
571                 goto err;
572
573         /* Error if trying to write more than maximum frame size. */
574         ret = -EMSGSIZE;
575         if (len > cf_sk->maxframe && cf_sk->sk.sk_protocol != CAIFPROTO_RFM)
576                 goto err;
577
578         buffer_size = len + cf_sk->headroom + cf_sk->tailroom;
579
580         ret = -ENOMEM;
581         skb = sock_alloc_send_skb(sk, buffer_size, noblock, &ret);
582
583         if (!skb || skb_tailroom(skb) < buffer_size)
584                 goto err;
585
586         skb_reserve(skb, cf_sk->headroom);
587
588         ret = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
589
590         if (ret)
591                 goto err;
592         ret = transmit_skb(skb, cf_sk, noblock, timeo);
593         if (ret < 0)
594                 goto err;
595         return len;
596 err:
597         kfree_skb(skb);
598         return ret;
599 }
600
601 /*
602  * Copied from unix_stream_sendmsg and adapted to CAIF:
603  * Changed removed permission handling and added waiting for flow on
604  * and other minor adaptations.
605  */
606 static int caif_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
607                                 struct msghdr *msg, size_t len)
608 {
609         struct sock *sk = sock->sk;
610         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
611         int err, size;
612         struct sk_buff *skb;
613         int sent = 0;
614         long timeo;
615
616         err = -EOPNOTSUPP;
617         if (unlikely(msg->msg_flags&MSG_OOB))
618                 goto out_err;
619
620         if (unlikely(msg->msg_namelen))
621                 goto out_err;
622
623         timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
624         timeo = caif_wait_for_flow_on(cf_sk, 1, timeo, &err);
625
626         if (unlikely(sk->sk_shutdown & SEND_SHUTDOWN))
627                 goto pipe_err;
628
629         while (sent < len) {
630
631                 size = len-sent;
632
633                 if (size > cf_sk->maxframe)
634                         size = cf_sk->maxframe;
635
636                 /* If size is more than half of sndbuf, chop up message */
637                 if (size > ((sk->sk_sndbuf >> 1) - 64))
638                         size = (sk->sk_sndbuf >> 1) - 64;
639
640                 if (size > SKB_MAX_ALLOC)
641                         size = SKB_MAX_ALLOC;
642
643                 skb = sock_alloc_send_skb(sk,
644                                         size + cf_sk->headroom +
645                                         cf_sk->tailroom,
646                                         msg->msg_flags&MSG_DONTWAIT,
647                                         &err);
648                 if (skb == NULL)
649                         goto out_err;
650
651                 skb_reserve(skb, cf_sk->headroom);
652                 /*
653                  *      If you pass two values to the sock_alloc_send_skb
654                  *      it tries to grab the large buffer with GFP_NOFS
655                  *      (which can fail easily), and if it fails grab the
656                  *      fallback size buffer which is under a page and will
657                  *      succeed. [Alan]
658                  */
659                 size = min_t(int, size, skb_tailroom(skb));
660
661                 err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size);
662                 if (err) {
663                         kfree_skb(skb);
664                         goto out_err;
665                 }
666                 err = transmit_skb(skb, cf_sk,
667                                 msg->msg_flags&MSG_DONTWAIT, timeo);
668                 if (err < 0) {
669                         kfree_skb(skb);
670                         goto pipe_err;
671                 }
672                 sent += size;
673         }
674
675         return sent;
676
677 pipe_err:
678         if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
679                 send_sig(SIGPIPE, current, 0);
680         err = -EPIPE;
681 out_err:
682         return sent ? : err;
683 }
684
685 static int setsockopt(struct socket *sock,
686                         int lvl, int opt, char __user *ov, unsigned int ol)
687 {
688         struct sock *sk = sock->sk;
689         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
690         int linksel;
691
692         if (cf_sk->sk.sk_socket->state != SS_UNCONNECTED)
693                 return -ENOPROTOOPT;
694
695         switch (opt) {
696         case CAIFSO_LINK_SELECT:
697                 if (ol < sizeof(int))
698                         return -EINVAL;
699                 if (lvl != SOL_CAIF)
700                         goto bad_sol;
701                 if (copy_from_user(&linksel, ov, sizeof(int)))
702                         return -EINVAL;
703                 lock_sock(&(cf_sk->sk));
704                 cf_sk->conn_req.link_selector = linksel;
705                 release_sock(&cf_sk->sk);
706                 return 0;
707
708         case CAIFSO_REQ_PARAM:
709                 if (lvl != SOL_CAIF)
710                         goto bad_sol;
711                 if (cf_sk->sk.sk_protocol != CAIFPROTO_UTIL)
712                         return -ENOPROTOOPT;
713                 lock_sock(&(cf_sk->sk));
714                 if (ol > sizeof(cf_sk->conn_req.param.data) ||
715                         copy_from_user(&cf_sk->conn_req.param.data, ov, ol)) {
716                         release_sock(&cf_sk->sk);
717                         return -EINVAL;
718                 }
719                 cf_sk->conn_req.param.size = ol;
720                 release_sock(&cf_sk->sk);
721                 return 0;
722
723         default:
724                 return -ENOPROTOOPT;
725         }
726
727         return 0;
728 bad_sol:
729         return -ENOPROTOOPT;
730
731 }
732
733 /*
734  * caif_connect() - Connect a CAIF Socket
735  * Copied and modified af_irda.c:irda_connect().
736  *
737  * Note : by consulting "errno", the user space caller may learn the cause
738  * of the failure. Most of them are visible in the function, others may come
739  * from subroutines called and are listed here :
740  *  o -EAFNOSUPPORT: bad socket family or type.
741  *  o -ESOCKTNOSUPPORT: bad socket type or protocol
742  *  o -EINVAL: bad socket address, or CAIF link type
743  *  o -ECONNREFUSED: remote end refused the connection.
744  *  o -EINPROGRESS: connect request sent but timed out (or non-blocking)
745  *  o -EISCONN: already connected.
746  *  o -ETIMEDOUT: Connection timed out (send timeout)
747  *  o -ENODEV: No link layer to send request
748  *  o -ECONNRESET: Received Shutdown indication or lost link layer
749  *  o -ENOMEM: Out of memory
750  *
751  *  State Strategy:
752  *  o sk_state: holds the CAIF_* protocol state, it's updated by
753  *      caif_ctrl_cb.
754  *  o sock->state: holds the SS_* socket state and is updated by connect and
755  *      disconnect.
756  */
757 static int caif_connect(struct socket *sock, struct sockaddr *uaddr,
758                         int addr_len, int flags)
759 {
760         struct sock *sk = sock->sk;
761         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
762         long timeo;
763         int err;
764         int ifindex, headroom, tailroom;
765         unsigned int mtu;
766         struct net_device *dev;
767
768         lock_sock(sk);
769
770         err = -EAFNOSUPPORT;
771         if (uaddr->sa_family != AF_CAIF)
772                 goto out;
773
774         switch (sock->state) {
775         case SS_UNCONNECTED:
776                 /* Normal case, a fresh connect */
777                 caif_assert(sk->sk_state == CAIF_DISCONNECTED);
778                 break;
779         case SS_CONNECTING:
780                 switch (sk->sk_state) {
781                 case CAIF_CONNECTED:
782                         sock->state = SS_CONNECTED;
783                         err = -EISCONN;
784                         goto out;
785                 case CAIF_DISCONNECTED:
786                         /* Reconnect allowed */
787                         break;
788                 case CAIF_CONNECTING:
789                         err = -EALREADY;
790                         if (flags & O_NONBLOCK)
791                                 goto out;
792                         goto wait_connect;
793                 }
794                 break;
795         case SS_CONNECTED:
796                 caif_assert(sk->sk_state == CAIF_CONNECTED ||
797                                 sk->sk_state == CAIF_DISCONNECTED);
798                 if (sk->sk_shutdown & SHUTDOWN_MASK) {
799                         /* Allow re-connect after SHUTDOWN_IND */
800                         caif_disconnect_client(&cf_sk->layer);
801                         break;
802                 }
803                 /* No reconnect on a seqpacket socket */
804                 err = -EISCONN;
805                 goto out;
806         case SS_DISCONNECTING:
807         case SS_FREE:
808                 caif_assert(1); /*Should never happen */
809                 break;
810         }
811         sk->sk_state = CAIF_DISCONNECTED;
812         sock->state = SS_UNCONNECTED;
813         sk_stream_kill_queues(&cf_sk->sk);
814
815         err = -EINVAL;
816         if (addr_len != sizeof(struct sockaddr_caif))
817                 goto out;
818
819         memcpy(&cf_sk->conn_req.sockaddr, uaddr,
820                 sizeof(struct sockaddr_caif));
821
822         /* Move to connecting socket, start sending Connect Requests */
823         sock->state = SS_CONNECTING;
824         sk->sk_state = CAIF_CONNECTING;
825
826         /* Check priority value coming from socket */
827         /* if priority value is out of range it will be ajusted */
828         if (cf_sk->sk.sk_priority > CAIF_PRIO_MAX)
829                 cf_sk->conn_req.priority = CAIF_PRIO_MAX;
830         else if (cf_sk->sk.sk_priority < CAIF_PRIO_MIN)
831                 cf_sk->conn_req.priority = CAIF_PRIO_MIN;
832         else
833                 cf_sk->conn_req.priority = cf_sk->sk.sk_priority;
834
835         /*ifindex = id of the interface.*/
836         cf_sk->conn_req.ifindex = cf_sk->sk.sk_bound_dev_if;
837
838         dbfs_atomic_inc(&cnt.num_connect_req);
839         cf_sk->layer.receive = caif_sktrecv_cb;
840         err = caif_connect_client(&cf_sk->conn_req,
841                                 &cf_sk->layer, &ifindex, &headroom, &tailroom);
842         if (err < 0) {
843                 cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
844                 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
845                 goto out;
846         }
847
848         err = -ENODEV;
849         rcu_read_lock();
850         dev = dev_get_by_index_rcu(sock_net(sk), ifindex);
851         if (!dev) {
852                 rcu_read_unlock();
853                 goto out;
854         }
855         cf_sk->headroom = LL_RESERVED_SPACE_EXTRA(dev, headroom);
856         mtu = dev->mtu;
857         rcu_read_unlock();
858
859         cf_sk->tailroom = tailroom;
860         cf_sk->maxframe = mtu - (headroom + tailroom);
861         if (cf_sk->maxframe < 1) {
862                 pr_warn("CAIF Interface MTU too small (%d)\n", dev->mtu);
863                 err = -ENODEV;
864                 goto out;
865         }
866
867         err = -EINPROGRESS;
868 wait_connect:
869
870         if (sk->sk_state != CAIF_CONNECTED && (flags & O_NONBLOCK))
871                 goto out;
872
873         timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
874
875         release_sock(sk);
876         err = -ERESTARTSYS;
877         timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
878                         sk->sk_state != CAIF_CONNECTING,
879                         timeo);
880         lock_sock(sk);
881         if (timeo < 0)
882                 goto out; /* -ERESTARTSYS */
883
884         err = -ETIMEDOUT;
885         if (timeo == 0 && sk->sk_state != CAIF_CONNECTED)
886                 goto out;
887         if (sk->sk_state != CAIF_CONNECTED) {
888                 sock->state = SS_UNCONNECTED;
889                 err = sock_error(sk);
890                 if (!err)
891                         err = -ECONNREFUSED;
892                 goto out;
893         }
894         sock->state = SS_CONNECTED;
895         err = 0;
896 out:
897         release_sock(sk);
898         return err;
899 }
900
901 /*
902  * caif_release() - Disconnect a CAIF Socket
903  * Copied and modified af_irda.c:irda_release().
904  */
905 static int caif_release(struct socket *sock)
906 {
907         struct sock *sk = sock->sk;
908         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
909         int res = 0;
910
911         if (!sk)
912                 return 0;
913
914         set_tx_flow_off(cf_sk);
915
916         /*
917          * Ensure that packets are not queued after this point in time.
918          * caif_queue_rcv_skb checks SOCK_DEAD holding the queue lock,
919          * this ensures no packets when sock is dead.
920          */
921         spin_lock(&sk->sk_receive_queue.lock);
922         sock_set_flag(sk, SOCK_DEAD);
923         spin_unlock(&sk->sk_receive_queue.lock);
924         sock->sk = NULL;
925
926         dbfs_atomic_inc(&cnt.num_disconnect);
927
928         if (cf_sk->debugfs_socket_dir != NULL)
929                 debugfs_remove_recursive(cf_sk->debugfs_socket_dir);
930
931         lock_sock(&(cf_sk->sk));
932         sk->sk_state = CAIF_DISCONNECTED;
933         sk->sk_shutdown = SHUTDOWN_MASK;
934
935         if (cf_sk->sk.sk_socket->state == SS_CONNECTED ||
936                 cf_sk->sk.sk_socket->state == SS_CONNECTING)
937                 res = caif_disconnect_client(&cf_sk->layer);
938
939         cf_sk->sk.sk_socket->state = SS_DISCONNECTING;
940         wake_up_interruptible_poll(sk_sleep(sk), POLLERR|POLLHUP);
941
942         sock_orphan(sk);
943         cf_sk->layer.dn = NULL;
944         sk_stream_kill_queues(&cf_sk->sk);
945         release_sock(sk);
946         sock_put(sk);
947         return res;
948 }
949
950 /* Copied from af_unix.c:unix_poll(), added CAIF tx_flow handling */
951 static unsigned int caif_poll(struct file *file,
952                                 struct socket *sock, poll_table *wait)
953 {
954         struct sock *sk = sock->sk;
955         unsigned int mask;
956         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
957
958         sock_poll_wait(file, sk_sleep(sk), wait);
959         mask = 0;
960
961         /* exceptional events? */
962         if (sk->sk_err)
963                 mask |= POLLERR;
964         if (sk->sk_shutdown == SHUTDOWN_MASK)
965                 mask |= POLLHUP;
966         if (sk->sk_shutdown & RCV_SHUTDOWN)
967                 mask |= POLLRDHUP;
968
969         /* readable? */
970         if (!skb_queue_empty(&sk->sk_receive_queue) ||
971                 (sk->sk_shutdown & RCV_SHUTDOWN))
972                 mask |= POLLIN | POLLRDNORM;
973
974         /*
975          * we set writable also when the other side has shut down the
976          * connection. This prevents stuck sockets.
977          */
978         if (sock_writeable(sk) && tx_flow_is_on(cf_sk))
979                 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
980
981         return mask;
982 }
983
984 static const struct proto_ops caif_seqpacket_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_seqpkt_sendmsg,
1000         .recvmsg = caif_seqpkt_recvmsg,
1001         .mmap = sock_no_mmap,
1002         .sendpage = sock_no_sendpage,
1003 };
1004
1005 static const struct proto_ops caif_stream_ops = {
1006         .family = PF_CAIF,
1007         .owner = THIS_MODULE,
1008         .release = caif_release,
1009         .bind = sock_no_bind,
1010         .connect = caif_connect,
1011         .socketpair = sock_no_socketpair,
1012         .accept = sock_no_accept,
1013         .getname = sock_no_getname,
1014         .poll = caif_poll,
1015         .ioctl = sock_no_ioctl,
1016         .listen = sock_no_listen,
1017         .shutdown = sock_no_shutdown,
1018         .setsockopt = setsockopt,
1019         .getsockopt = sock_no_getsockopt,
1020         .sendmsg = caif_stream_sendmsg,
1021         .recvmsg = caif_stream_recvmsg,
1022         .mmap = sock_no_mmap,
1023         .sendpage = sock_no_sendpage,
1024 };
1025
1026 /* This function is called when a socket is finally destroyed. */
1027 static void caif_sock_destructor(struct sock *sk)
1028 {
1029         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
1030         caif_assert(!atomic_read(&sk->sk_wmem_alloc));
1031         caif_assert(sk_unhashed(sk));
1032         caif_assert(!sk->sk_socket);
1033         if (!sock_flag(sk, SOCK_DEAD)) {
1034                 pr_info("Attempt to release alive CAIF socket: %p\n", sk);
1035                 return;
1036         }
1037         sk_stream_kill_queues(&cf_sk->sk);
1038         dbfs_atomic_dec(&cnt.caif_nr_socks);
1039 }
1040
1041 static int caif_create(struct net *net, struct socket *sock, int protocol,
1042                         int kern)
1043 {
1044         struct sock *sk = NULL;
1045         struct caifsock *cf_sk = NULL;
1046         static struct proto prot = {.name = "PF_CAIF",
1047                 .owner = THIS_MODULE,
1048                 .obj_size = sizeof(struct caifsock),
1049         };
1050
1051         if (!capable(CAP_SYS_ADMIN) && !capable(CAP_NET_ADMIN))
1052                 return -EPERM;
1053         /*
1054          * The sock->type specifies the socket type to use.
1055          * The CAIF socket is a packet stream in the sense
1056          * that it is packet based. CAIF trusts the reliability
1057          * of the link, no resending is implemented.
1058          */
1059         if (sock->type == SOCK_SEQPACKET)
1060                 sock->ops = &caif_seqpacket_ops;
1061         else if (sock->type == SOCK_STREAM)
1062                 sock->ops = &caif_stream_ops;
1063         else
1064                 return -ESOCKTNOSUPPORT;
1065
1066         if (protocol < 0 || protocol >= CAIFPROTO_MAX)
1067                 return -EPROTONOSUPPORT;
1068         /*
1069          * Set the socket state to unconnected.  The socket state
1070          * is really not used at all in the net/core or socket.c but the
1071          * initialization makes sure that sock->state is not uninitialized.
1072          */
1073         sk = sk_alloc(net, PF_CAIF, GFP_KERNEL, &prot);
1074         if (!sk)
1075                 return -ENOMEM;
1076
1077         cf_sk = container_of(sk, struct caifsock, sk);
1078
1079         /* Store the protocol */
1080         sk->sk_protocol = (unsigned char) protocol;
1081
1082         /*
1083          * Lock in order to try to stop someone from opening the socket
1084          * too early.
1085          */
1086         lock_sock(&(cf_sk->sk));
1087
1088         /* Initialize the nozero default sock structure data. */
1089         sock_init_data(sock, sk);
1090         sk->sk_destruct = caif_sock_destructor;
1091
1092         mutex_init(&cf_sk->readlock); /* single task reading lock */
1093         cf_sk->layer.ctrlcmd = caif_ctrl_cb;
1094         cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
1095         cf_sk->sk.sk_state = CAIF_DISCONNECTED;
1096
1097         set_tx_flow_off(cf_sk);
1098         set_rx_flow_on(cf_sk);
1099
1100         /* Set default options on configuration */
1101         cf_sk->sk.sk_priority= CAIF_PRIO_NORMAL;
1102         cf_sk->conn_req.link_selector = CAIF_LINK_LOW_LATENCY;
1103         cf_sk->conn_req.protocol = protocol;
1104         /* Increase the number of sockets created. */
1105         dbfs_atomic_inc(&cnt.caif_nr_socks);
1106 #ifdef CONFIG_DEBUG_FS
1107         if (!IS_ERR(debugfsdir)) {
1108                 /* Fill in some information concerning the misc socket. */
1109                 snprintf(cf_sk->name, sizeof(cf_sk->name), "cfsk%d",
1110                                 atomic_read(&cnt.caif_nr_socks));
1111
1112                 cf_sk->debugfs_socket_dir =
1113                         debugfs_create_dir(cf_sk->name, debugfsdir);
1114                 debugfs_create_u32("sk_state", S_IRUSR | S_IWUSR,
1115                                 cf_sk->debugfs_socket_dir,
1116                                 (u32 *) &cf_sk->sk.sk_state);
1117                 debugfs_create_u32("flow_state", S_IRUSR | S_IWUSR,
1118                                 cf_sk->debugfs_socket_dir, &cf_sk->flow_state);
1119                 debugfs_create_u32("sk_rmem_alloc", S_IRUSR | S_IWUSR,
1120                                 cf_sk->debugfs_socket_dir,
1121                                 (u32 *) &cf_sk->sk.sk_rmem_alloc);
1122                 debugfs_create_u32("sk_wmem_alloc", S_IRUSR | S_IWUSR,
1123                                 cf_sk->debugfs_socket_dir,
1124                                 (u32 *) &cf_sk->sk.sk_wmem_alloc);
1125                 debugfs_create_u32("identity", S_IRUSR | S_IWUSR,
1126                                 cf_sk->debugfs_socket_dir,
1127                                 (u32 *) &cf_sk->layer.id);
1128         }
1129 #endif
1130         release_sock(&cf_sk->sk);
1131         return 0;
1132 }
1133
1134
1135 static struct net_proto_family caif_family_ops = {
1136         .family = PF_CAIF,
1137         .create = caif_create,
1138         .owner = THIS_MODULE,
1139 };
1140
1141 static int af_caif_init(void)
1142 {
1143         int err = sock_register(&caif_family_ops);
1144         if (!err)
1145                 return err;
1146         return 0;
1147 }
1148
1149 static int __init caif_sktinit_module(void)
1150 {
1151 #ifdef CONFIG_DEBUG_FS
1152         debugfsdir = debugfs_create_dir("caif_sk", NULL);
1153         if (!IS_ERR(debugfsdir)) {
1154                 debugfs_create_u32("num_sockets", S_IRUSR | S_IWUSR,
1155                                 debugfsdir,
1156                                 (u32 *) &cnt.caif_nr_socks);
1157                 debugfs_create_u32("num_connect_req", S_IRUSR | S_IWUSR,
1158                                 debugfsdir,
1159                                 (u32 *) &cnt.num_connect_req);
1160                 debugfs_create_u32("num_connect_resp", S_IRUSR | S_IWUSR,
1161                                 debugfsdir,
1162                                 (u32 *) &cnt.num_connect_resp);
1163                 debugfs_create_u32("num_connect_fail_resp", S_IRUSR | S_IWUSR,
1164                                 debugfsdir,
1165                                 (u32 *) &cnt.num_connect_fail_resp);
1166                 debugfs_create_u32("num_disconnect", S_IRUSR | S_IWUSR,
1167                                 debugfsdir,
1168                                 (u32 *) &cnt.num_disconnect);
1169                 debugfs_create_u32("num_remote_shutdown_ind",
1170                                 S_IRUSR | S_IWUSR, debugfsdir,
1171                                 (u32 *) &cnt.num_remote_shutdown_ind);
1172                 debugfs_create_u32("num_tx_flow_off_ind", S_IRUSR | S_IWUSR,
1173                                 debugfsdir,
1174                                 (u32 *) &cnt.num_tx_flow_off_ind);
1175                 debugfs_create_u32("num_tx_flow_on_ind", S_IRUSR | S_IWUSR,
1176                                 debugfsdir,
1177                                 (u32 *) &cnt.num_tx_flow_on_ind);
1178                 debugfs_create_u32("num_rx_flow_off", S_IRUSR | S_IWUSR,
1179                                 debugfsdir,
1180                                 (u32 *) &cnt.num_rx_flow_off);
1181                 debugfs_create_u32("num_rx_flow_on", S_IRUSR | S_IWUSR,
1182                                 debugfsdir,
1183                                 (u32 *) &cnt.num_rx_flow_on);
1184         }
1185 #endif
1186         return af_caif_init();
1187 }
1188
1189 static void __exit caif_sktexit_module(void)
1190 {
1191         sock_unregister(PF_CAIF);
1192         if (debugfsdir != NULL)
1193                 debugfs_remove_recursive(debugfsdir);
1194 }
1195 module_init(caif_sktinit_module);
1196 module_exit(caif_sktexit_module);