1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) ST-Ericsson AB 2010
4 * Author: Sjur Brendeland
5 */
6
7#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
8
9#include <linux/filter.h>
10#include <linux/fs.h>
11#include <linux/init.h>
12#include <linux/module.h>
13#include <linux/sched/signal.h>
14#include <linux/spinlock.h>
15#include <linux/mutex.h>
16#include <linux/list.h>
17#include <linux/wait.h>
18#include <linux/poll.h>
19#include <linux/tcp.h>
20#include <linux/uaccess.h>
21#include <linux/debugfs.h>
22#include <linux/caif/caif_socket.h>
23#include <linux/pkt_sched.h>
24#include <net/sock.h>
25#include <net/tcp_states.h>
26#include <net/caif/caif_layer.h>
27#include <net/caif/caif_dev.h>
28#include <net/caif/cfpkt.h>
29
30MODULE_DESCRIPTION("ST-Ericsson CAIF modem protocol socket support (AF_CAIF)");
31MODULE_LICENSE("GPL");
32MODULE_ALIAS_NETPROTO(AF_CAIF);
33
34/*
35 * CAIF state is re-using the TCP socket states.
36 * caif_states stored in sk_state reflect the state as reported by
37 * the CAIF stack, while sk_socket->state is the state of the socket.
38 */
39enum caif_states {
40 CAIF_CONNECTED = TCP_ESTABLISHED,
41 CAIF_CONNECTING = TCP_SYN_SENT,
42 CAIF_DISCONNECTED = TCP_CLOSE
43};
44
45#define TX_FLOW_ON_BIT 1
46#define RX_FLOW_ON_BIT 2
47
48struct caifsock {
49 struct sock sk; /* must be first member */
50 struct cflayer layer;
51 unsigned long flow_state;
52 struct caif_connect_request conn_req;
53 struct mutex readlock;
54 struct dentry *debugfs_socket_dir;
55 int headroom, tailroom, maxframe;
56};
57
58static int rx_flow_is_on(struct caifsock *cf_sk)
59{
60 return test_bit(RX_FLOW_ON_BIT, &cf_sk->flow_state);
61}
62
63static int tx_flow_is_on(struct caifsock *cf_sk)
64{
65 return test_bit(TX_FLOW_ON_BIT, &cf_sk->flow_state);
66}
67
68static void set_rx_flow_off(struct caifsock *cf_sk)
69{
70 clear_bit(RX_FLOW_ON_BIT, addr: &cf_sk->flow_state);
71}
72
73static void set_rx_flow_on(struct caifsock *cf_sk)
74{
75 set_bit(RX_FLOW_ON_BIT, addr: &cf_sk->flow_state);
76}
77
78static void set_tx_flow_off(struct caifsock *cf_sk)
79{
80 clear_bit(TX_FLOW_ON_BIT, addr: &cf_sk->flow_state);
81}
82
83static void set_tx_flow_on(struct caifsock *cf_sk)
84{
85 set_bit(TX_FLOW_ON_BIT, addr: &cf_sk->flow_state);
86}
87
88static void caif_read_lock(struct sock *sk)
89{
90 struct caifsock *cf_sk;
91 cf_sk = container_of(sk, struct caifsock, sk);
92 mutex_lock(&cf_sk->readlock);
93}
94
95static void caif_read_unlock(struct sock *sk)
96{
97 struct caifsock *cf_sk;
98 cf_sk = container_of(sk, struct caifsock, sk);
99 mutex_unlock(lock: &cf_sk->readlock);
100}
101
102static int sk_rcvbuf_lowwater(struct caifsock *cf_sk)
103{
104 /* A quarter of full buffer is used a low water mark */
105 return cf_sk->sk.sk_rcvbuf / 4;
106}
107
108static void caif_flow_ctrl(struct sock *sk, int mode)
109{
110 struct caifsock *cf_sk;
111 cf_sk = container_of(sk, struct caifsock, sk);
112 if (cf_sk->layer.dn && cf_sk->layer.dn->modemcmd)
113 cf_sk->layer.dn->modemcmd(cf_sk->layer.dn, mode);
114}
115
116/*
117 * Copied from sock.c:sock_queue_rcv_skb(), but changed so packets are
118 * not dropped, but CAIF is sending flow off instead.
119 */
120static void caif_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
121{
122 int err;
123 unsigned long flags;
124 struct sk_buff_head *list = &sk->sk_receive_queue;
125 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
126 bool queued = false;
127
128 if (atomic_read(v: &sk->sk_rmem_alloc) + skb->truesize >=
129 (unsigned int)sk->sk_rcvbuf && rx_flow_is_on(cf_sk)) {
130 net_dbg_ratelimited("sending flow OFF (queue len = %d %d)\n",
131 atomic_read(&cf_sk->sk.sk_rmem_alloc),
132 sk_rcvbuf_lowwater(cf_sk));
133 set_rx_flow_off(cf_sk);
134 caif_flow_ctrl(sk, mode: CAIF_MODEMCMD_FLOW_OFF_REQ);
135 }
136
137 err = sk_filter(sk, skb);
138 if (err)
139 goto out;
140
141 if (!sk_rmem_schedule(sk, skb, size: skb->truesize) && rx_flow_is_on(cf_sk)) {
142 set_rx_flow_off(cf_sk);
143 net_dbg_ratelimited("sending flow OFF due to rmem_schedule\n");
144 caif_flow_ctrl(sk, mode: CAIF_MODEMCMD_FLOW_OFF_REQ);
145 }
146 skb->dev = NULL;
147 skb_set_owner_r(skb, sk);
148 spin_lock_irqsave(&list->lock, flags);
149 queued = !sock_flag(sk, flag: SOCK_DEAD);
150 if (queued)
151 __skb_queue_tail(list, newsk: skb);
152 spin_unlock_irqrestore(lock: &list->lock, flags);
153out:
154 if (queued)
155 sk->sk_data_ready(sk);
156 else
157 kfree_skb(skb);
158}
159
160/* Packet Receive Callback function called from CAIF Stack */
161static int caif_sktrecv_cb(struct cflayer *layr, struct cfpkt *pkt)
162{
163 struct caifsock *cf_sk;
164 struct sk_buff *skb;
165
166 cf_sk = container_of(layr, struct caifsock, layer);
167 skb = cfpkt_tonative(pkt);
168
169 if (unlikely(cf_sk->sk.sk_state != CAIF_CONNECTED)) {
170 kfree_skb(skb);
171 return 0;
172 }
173 caif_queue_rcv_skb(sk: &cf_sk->sk, skb);
174 return 0;
175}
176
177static void cfsk_hold(struct cflayer *layr)
178{
179 struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
180 sock_hold(sk: &cf_sk->sk);
181}
182
183static void cfsk_put(struct cflayer *layr)
184{
185 struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
186 sock_put(sk: &cf_sk->sk);
187}
188
189/* Packet Control Callback function called from CAIF */
190static void caif_ctrl_cb(struct cflayer *layr,
191 enum caif_ctrlcmd flow,
192 int phyid)
193{
194 struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
195 switch (flow) {
196 case CAIF_CTRLCMD_FLOW_ON_IND:
197 /* OK from modem to start sending again */
198 set_tx_flow_on(cf_sk);
199 cf_sk->sk.sk_state_change(&cf_sk->sk);
200 break;
201
202 case CAIF_CTRLCMD_FLOW_OFF_IND:
203 /* Modem asks us to shut up */
204 set_tx_flow_off(cf_sk);
205 cf_sk->sk.sk_state_change(&cf_sk->sk);
206 break;
207
208 case CAIF_CTRLCMD_INIT_RSP:
209 /* We're now connected */
210 caif_client_register_refcnt(adapt_layer: &cf_sk->layer,
211 hold: cfsk_hold, put: cfsk_put);
212 cf_sk->sk.sk_state = CAIF_CONNECTED;
213 set_tx_flow_on(cf_sk);
214 cf_sk->sk.sk_shutdown = 0;
215 cf_sk->sk.sk_state_change(&cf_sk->sk);
216 break;
217
218 case CAIF_CTRLCMD_DEINIT_RSP:
219 /* We're now disconnected */
220 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
221 cf_sk->sk.sk_state_change(&cf_sk->sk);
222 break;
223
224 case CAIF_CTRLCMD_INIT_FAIL_RSP:
225 /* Connect request failed */
226 cf_sk->sk.sk_err = ECONNREFUSED;
227 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
228 cf_sk->sk.sk_shutdown = SHUTDOWN_MASK;
229 /*
230 * Socket "standards" seems to require POLLOUT to
231 * be set at connect failure.
232 */
233 set_tx_flow_on(cf_sk);
234 cf_sk->sk.sk_state_change(&cf_sk->sk);
235 break;
236
237 case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
238 /* Modem has closed this connection, or device is down. */
239 cf_sk->sk.sk_shutdown = SHUTDOWN_MASK;
240 cf_sk->sk.sk_err = ECONNRESET;
241 set_rx_flow_on(cf_sk);
242 sk_error_report(sk: &cf_sk->sk);
243 break;
244
245 default:
246 pr_debug("Unexpected flow command %d\n", flow);
247 }
248}
249
250static void caif_check_flow_release(struct sock *sk)
251{
252 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
253
254 if (rx_flow_is_on(cf_sk))
255 return;
256
257 if (atomic_read(v: &sk->sk_rmem_alloc) <= sk_rcvbuf_lowwater(cf_sk)) {
258 set_rx_flow_on(cf_sk);
259 caif_flow_ctrl(sk, mode: CAIF_MODEMCMD_FLOW_ON_REQ);
260 }
261}
262
263/*
264 * Copied from unix_dgram_recvmsg, but removed credit checks,
265 * changed locking, address handling and added MSG_TRUNC.
266 */
267static int caif_seqpkt_recvmsg(struct socket *sock, struct msghdr *m,
268 size_t len, int flags)
269
270{
271 struct sock *sk = sock->sk;
272 struct sk_buff *skb;
273 int ret;
274 int copylen;
275
276 ret = -EOPNOTSUPP;
277 if (flags & MSG_OOB)
278 goto read_error;
279
280 skb = skb_recv_datagram(sk, flags, err: &ret);
281 if (!skb)
282 goto read_error;
283 copylen = skb->len;
284 if (len < copylen) {
285 m->msg_flags |= MSG_TRUNC;
286 copylen = len;
287 }
288
289 ret = skb_copy_datagram_msg(from: skb, offset: 0, msg: m, size: copylen);
290 if (ret)
291 goto out_free;
292
293 ret = (flags & MSG_TRUNC) ? skb->len : copylen;
294out_free:
295 skb_free_datagram(sk, skb);
296 caif_check_flow_release(sk);
297 return ret;
298
299read_error:
300 return ret;
301}
302
303
304/* Copied from unix_stream_wait_data, identical except for lock call. */
305static long caif_stream_data_wait(struct sock *sk, long timeo)
306{
307 DEFINE_WAIT(wait);
308 lock_sock(sk);
309
310 for (;;) {
311 prepare_to_wait(wq_head: sk_sleep(sk), wq_entry: &wait, TASK_INTERRUPTIBLE);
312
313 if (!skb_queue_empty(list: &sk->sk_receive_queue) ||
314 sk->sk_err ||
315 sk->sk_state != CAIF_CONNECTED ||
316 sock_flag(sk, flag: SOCK_DEAD) ||
317 (sk->sk_shutdown & RCV_SHUTDOWN) ||
318 signal_pending(current) ||
319 !timeo)
320 break;
321
322 sk_set_bit(nr: SOCKWQ_ASYNC_WAITDATA, sk);
323 release_sock(sk);
324 timeo = schedule_timeout(timeout: timeo);
325 lock_sock(sk);
326
327 if (sock_flag(sk, flag: SOCK_DEAD))
328 break;
329
330 sk_clear_bit(nr: SOCKWQ_ASYNC_WAITDATA, sk);
331 }
332
333 finish_wait(wq_head: sk_sleep(sk), wq_entry: &wait);
334 release_sock(sk);
335 return timeo;
336}
337
338
339/*
340 * Copied from unix_stream_recvmsg, but removed credit checks,
341 * changed locking calls, changed address handling.
342 */
343static int caif_stream_recvmsg(struct socket *sock, struct msghdr *msg,
344 size_t size, int flags)
345{
346 struct sock *sk = sock->sk;
347 int copied = 0;
348 int target;
349 int err = 0;
350 long timeo;
351
352 err = -EOPNOTSUPP;
353 if (flags&MSG_OOB)
354 goto out;
355
356 /*
357 * Lock the socket to prevent queue disordering
358 * while sleeps in memcpy_tomsg
359 */
360 err = -EAGAIN;
361 if (sk->sk_state == CAIF_CONNECTING)
362 goto out;
363
364 caif_read_lock(sk);
365 target = sock_rcvlowat(sk, waitall: flags&MSG_WAITALL, len: size);
366 timeo = sock_rcvtimeo(sk, noblock: flags&MSG_DONTWAIT);
367
368 do {
369 int chunk;
370 struct sk_buff *skb;
371
372 lock_sock(sk);
373 if (sock_flag(sk, flag: SOCK_DEAD)) {
374 err = -ECONNRESET;
375 goto unlock;
376 }
377 skb = skb_dequeue(list: &sk->sk_receive_queue);
378 caif_check_flow_release(sk);
379
380 if (skb == NULL) {
381 if (copied >= target)
382 goto unlock;
383 /*
384 * POSIX 1003.1g mandates this order.
385 */
386 err = sock_error(sk);
387 if (err)
388 goto unlock;
389 err = -ECONNRESET;
390 if (sk->sk_shutdown & RCV_SHUTDOWN)
391 goto unlock;
392
393 err = -EPIPE;
394 if (sk->sk_state != CAIF_CONNECTED)
395 goto unlock;
396 if (sock_flag(sk, flag: SOCK_DEAD))
397 goto unlock;
398
399 release_sock(sk);
400
401 err = -EAGAIN;
402 if (!timeo)
403 break;
404
405 caif_read_unlock(sk);
406
407 timeo = caif_stream_data_wait(sk, timeo);
408
409 if (signal_pending(current)) {
410 err = sock_intr_errno(timeo);
411 goto out;
412 }
413 caif_read_lock(sk);
414 continue;
415unlock:
416 release_sock(sk);
417 break;
418 }
419 release_sock(sk);
420 chunk = min_t(unsigned int, skb->len, size);
421 if (memcpy_to_msg(msg, data: skb->data, len: chunk)) {
422 skb_queue_head(list: &sk->sk_receive_queue, newsk: skb);
423 if (copied == 0)
424 copied = -EFAULT;
425 break;
426 }
427 copied += chunk;
428 size -= chunk;
429
430 /* Mark read part of skb as used */
431 if (!(flags & MSG_PEEK)) {
432 skb_pull(skb, len: chunk);
433
434 /* put the skb back if we didn't use it up. */
435 if (skb->len) {
436 skb_queue_head(list: &sk->sk_receive_queue, newsk: skb);
437 break;
438 }
439 kfree_skb(skb);
440
441 } else {
442 /*
443 * It is questionable, see note in unix_dgram_recvmsg.
444 */
445 /* put message back and return */
446 skb_queue_head(list: &sk->sk_receive_queue, newsk: skb);
447 break;
448 }
449 } while (size);
450 caif_read_unlock(sk);
451
452out:
453 return copied ? : err;
454}
455
456/*
457 * Copied from sock.c:sock_wait_for_wmem, but change to wait for
458 * CAIF flow-on and sock_writable.
459 */
460static long caif_wait_for_flow_on(struct caifsock *cf_sk,
461 int wait_writeable, long timeo, int *err)
462{
463 struct sock *sk = &cf_sk->sk;
464 DEFINE_WAIT(wait);
465 for (;;) {
466 *err = 0;
467 if (tx_flow_is_on(cf_sk) &&
468 (!wait_writeable || sock_writeable(sk: &cf_sk->sk)))
469 break;
470 *err = -ETIMEDOUT;
471 if (!timeo)
472 break;
473 *err = -ERESTARTSYS;
474 if (signal_pending(current))
475 break;
476 prepare_to_wait(wq_head: sk_sleep(sk), wq_entry: &wait, TASK_INTERRUPTIBLE);
477 *err = -ECONNRESET;
478 if (sk->sk_shutdown & SHUTDOWN_MASK)
479 break;
480 *err = -sk->sk_err;
481 if (sk->sk_err)
482 break;
483 *err = -EPIPE;
484 if (cf_sk->sk.sk_state != CAIF_CONNECTED)
485 break;
486 timeo = schedule_timeout(timeout: timeo);
487 }
488 finish_wait(wq_head: sk_sleep(sk), wq_entry: &wait);
489 return timeo;
490}
491
492/*
493 * Transmit a SKB. The device may temporarily request re-transmission
494 * by returning EAGAIN.
495 */
496static int transmit_skb(struct sk_buff *skb, struct caifsock *cf_sk,
497 int noblock, long timeo)
498{
499 struct cfpkt *pkt;
500
501 pkt = cfpkt_fromnative(dir: CAIF_DIR_OUT, nativepkt: skb);
502 memset(skb->cb, 0, sizeof(struct caif_payload_info));
503 cfpkt_set_prio(pkt, prio: cf_sk->sk.sk_priority);
504
505 if (cf_sk->layer.dn == NULL) {
506 kfree_skb(skb);
507 return -EINVAL;
508 }
509
510 return cf_sk->layer.dn->transmit(cf_sk->layer.dn, pkt);
511}
512
513/* Copied from af_unix:unix_dgram_sendmsg, and adapted to CAIF */
514static int caif_seqpkt_sendmsg(struct socket *sock, struct msghdr *msg,
515 size_t len)
516{
517 struct sock *sk = sock->sk;
518 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
519 int buffer_size;
520 int ret = 0;
521 struct sk_buff *skb = NULL;
522 int noblock;
523 long timeo;
524 caif_assert(cf_sk);
525 ret = sock_error(sk);
526 if (ret)
527 goto err;
528
529 ret = -EOPNOTSUPP;
530 if (msg->msg_flags&MSG_OOB)
531 goto err;
532
533 ret = -EOPNOTSUPP;
534 if (msg->msg_namelen)
535 goto err;
536
537 noblock = msg->msg_flags & MSG_DONTWAIT;
538
539 timeo = sock_sndtimeo(sk, noblock);
540 timeo = caif_wait_for_flow_on(container_of(sk, struct caifsock, sk),
541 wait_writeable: 1, timeo, err: &ret);
542
543 if (ret)
544 goto err;
545 ret = -EPIPE;
546 if (cf_sk->sk.sk_state != CAIF_CONNECTED ||
547 sock_flag(sk, flag: SOCK_DEAD) ||
548 (sk->sk_shutdown & RCV_SHUTDOWN))
549 goto err;
550
551 /* Error if trying to write more than maximum frame size. */
552 ret = -EMSGSIZE;
553 if (len > cf_sk->maxframe && cf_sk->sk.sk_protocol != CAIFPROTO_RFM)
554 goto err;
555
556 buffer_size = len + cf_sk->headroom + cf_sk->tailroom;
557
558 ret = -ENOMEM;
559 skb = sock_alloc_send_skb(sk, size: buffer_size, noblock, errcode: &ret);
560
561 if (!skb || skb_tailroom(skb) < buffer_size)
562 goto err;
563
564 skb_reserve(skb, len: cf_sk->headroom);
565
566 ret = memcpy_from_msg(data: skb_put(skb, len), msg, len);
567
568 if (ret)
569 goto err;
570 ret = transmit_skb(skb, cf_sk, noblock, timeo);
571 if (ret < 0)
572 /* skb is already freed */
573 return ret;
574
575 return len;
576err:
577 kfree_skb(skb);
578 return ret;
579}
580
581/*
582 * Copied from unix_stream_sendmsg and adapted to CAIF:
583 * Changed removed permission handling and added waiting for flow on
584 * and other minor adaptations.
585 */
586static int caif_stream_sendmsg(struct socket *sock, struct msghdr *msg,
587 size_t len)
588{
589 struct sock *sk = sock->sk;
590 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
591 int err, size;
592 struct sk_buff *skb;
593 int sent = 0;
594 long timeo;
595
596 err = -EOPNOTSUPP;
597 if (unlikely(msg->msg_flags&MSG_OOB))
598 goto out_err;
599
600 if (unlikely(msg->msg_namelen))
601 goto out_err;
602
603 timeo = sock_sndtimeo(sk, noblock: msg->msg_flags & MSG_DONTWAIT);
604 timeo = caif_wait_for_flow_on(cf_sk, wait_writeable: 1, timeo, err: &err);
605
606 if (unlikely(sk->sk_shutdown & SEND_SHUTDOWN))
607 goto pipe_err;
608
609 while (sent < len) {
610
611 size = len-sent;
612
613 if (size > cf_sk->maxframe)
614 size = cf_sk->maxframe;
615
616 /* If size is more than half of sndbuf, chop up message */
617 if (size > ((sk->sk_sndbuf >> 1) - 64))
618 size = (sk->sk_sndbuf >> 1) - 64;
619
620 if (size > SKB_MAX_ALLOC)
621 size = SKB_MAX_ALLOC;
622
623 skb = sock_alloc_send_skb(sk,
624 size: size + cf_sk->headroom +
625 cf_sk->tailroom,
626 noblock: msg->msg_flags&MSG_DONTWAIT,
627 errcode: &err);
628 if (skb == NULL)
629 goto out_err;
630
631 skb_reserve(skb, len: cf_sk->headroom);
632 /*
633 * If you pass two values to the sock_alloc_send_skb
634 * it tries to grab the large buffer with GFP_NOFS
635 * (which can fail easily), and if it fails grab the
636 * fallback size buffer which is under a page and will
637 * succeed. [Alan]
638 */
639 size = min_t(int, size, skb_tailroom(skb));
640
641 err = memcpy_from_msg(data: skb_put(skb, len: size), msg, len: size);
642 if (err) {
643 kfree_skb(skb);
644 goto out_err;
645 }
646 err = transmit_skb(skb, cf_sk,
647 noblock: msg->msg_flags&MSG_DONTWAIT, timeo);
648 if (err < 0)
649 /* skb is already freed */
650 goto pipe_err;
651
652 sent += size;
653 }
654
655 return sent;
656
657pipe_err:
658 if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
659 send_sig(SIGPIPE, current, 0);
660 err = -EPIPE;
661out_err:
662 return sent ? : err;
663}
664
665static int setsockopt(struct socket *sock, int lvl, int opt, sockptr_t ov,
666 unsigned int ol)
667{
668 struct sock *sk = sock->sk;
669 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
670 int linksel;
671
672 if (cf_sk->sk.sk_socket->state != SS_UNCONNECTED)
673 return -ENOPROTOOPT;
674
675 switch (opt) {
676 case CAIFSO_LINK_SELECT:
677 if (ol < sizeof(int))
678 return -EINVAL;
679 if (lvl != SOL_CAIF)
680 goto bad_sol;
681 if (copy_from_sockptr(dst: &linksel, src: ov, size: sizeof(int)))
682 return -EINVAL;
683 lock_sock(sk: &(cf_sk->sk));
684 cf_sk->conn_req.link_selector = linksel;
685 release_sock(sk: &cf_sk->sk);
686 return 0;
687
688 case CAIFSO_REQ_PARAM:
689 if (lvl != SOL_CAIF)
690 goto bad_sol;
691 if (cf_sk->sk.sk_protocol != CAIFPROTO_UTIL)
692 return -ENOPROTOOPT;
693 lock_sock(sk: &(cf_sk->sk));
694 if (ol > sizeof(cf_sk->conn_req.param.data) ||
695 copy_from_sockptr(dst: &cf_sk->conn_req.param.data, src: ov, size: ol)) {
696 release_sock(sk: &cf_sk->sk);
697 return -EINVAL;
698 }
699 cf_sk->conn_req.param.size = ol;
700 release_sock(sk: &cf_sk->sk);
701 return 0;
702
703 default:
704 return -ENOPROTOOPT;
705 }
706
707 return 0;
708bad_sol:
709 return -ENOPROTOOPT;
710
711}
712
713/*
714 * caif_connect() - Connect a CAIF Socket
715 * Copied and modified af_irda.c:irda_connect().
716 *
717 * Note : by consulting "errno", the user space caller may learn the cause
718 * of the failure. Most of them are visible in the function, others may come
719 * from subroutines called and are listed here :
720 * o -EAFNOSUPPORT: bad socket family or type.
721 * o -ESOCKTNOSUPPORT: bad socket type or protocol
722 * o -EINVAL: bad socket address, or CAIF link type
723 * o -ECONNREFUSED: remote end refused the connection.
724 * o -EINPROGRESS: connect request sent but timed out (or non-blocking)
725 * o -EISCONN: already connected.
726 * o -ETIMEDOUT: Connection timed out (send timeout)
727 * o -ENODEV: No link layer to send request
728 * o -ECONNRESET: Received Shutdown indication or lost link layer
729 * o -ENOMEM: Out of memory
730 *
731 * State Strategy:
732 * o sk_state: holds the CAIF_* protocol state, it's updated by
733 * caif_ctrl_cb.
734 * o sock->state: holds the SS_* socket state and is updated by connect and
735 * disconnect.
736 */
737static int caif_connect(struct socket *sock, struct sockaddr *uaddr,
738 int addr_len, int flags)
739{
740 struct sock *sk = sock->sk;
741 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
742 long timeo;
743 int err;
744 int ifindex, headroom, tailroom;
745 unsigned int mtu;
746 struct net_device *dev;
747
748 lock_sock(sk);
749
750 err = -EINVAL;
751 if (addr_len < offsetofend(struct sockaddr, sa_family))
752 goto out;
753
754 err = -EAFNOSUPPORT;
755 if (uaddr->sa_family != AF_CAIF)
756 goto out;
757
758 switch (sock->state) {
759 case SS_UNCONNECTED:
760 /* Normal case, a fresh connect */
761 caif_assert(sk->sk_state == CAIF_DISCONNECTED);
762 break;
763 case SS_CONNECTING:
764 switch (sk->sk_state) {
765 case CAIF_CONNECTED:
766 sock->state = SS_CONNECTED;
767 err = -EISCONN;
768 goto out;
769 case CAIF_DISCONNECTED:
770 /* Reconnect allowed */
771 break;
772 case CAIF_CONNECTING:
773 err = -EALREADY;
774 if (flags & O_NONBLOCK)
775 goto out;
776 goto wait_connect;
777 }
778 break;
779 case SS_CONNECTED:
780 caif_assert(sk->sk_state == CAIF_CONNECTED ||
781 sk->sk_state == CAIF_DISCONNECTED);
782 if (sk->sk_shutdown & SHUTDOWN_MASK) {
783 /* Allow re-connect after SHUTDOWN_IND */
784 caif_disconnect_client(net: sock_net(sk), client_layer: &cf_sk->layer);
785 caif_free_client(adap_layer: &cf_sk->layer);
786 break;
787 }
788 /* No reconnect on a seqpacket socket */
789 err = -EISCONN;
790 goto out;
791 case SS_DISCONNECTING:
792 case SS_FREE:
793 caif_assert(1); /*Should never happen */
794 break;
795 }
796 sk->sk_state = CAIF_DISCONNECTED;
797 sock->state = SS_UNCONNECTED;
798 sk_stream_kill_queues(sk: &cf_sk->sk);
799
800 err = -EINVAL;
801 if (addr_len != sizeof(struct sockaddr_caif))
802 goto out;
803
804 memcpy(&cf_sk->conn_req.sockaddr, uaddr,
805 sizeof(struct sockaddr_caif));
806
807 /* Move to connecting socket, start sending Connect Requests */
808 sock->state = SS_CONNECTING;
809 sk->sk_state = CAIF_CONNECTING;
810
811 /* Check priority value comming from socket */
812 /* if priority value is out of range it will be ajusted */
813 if (cf_sk->sk.sk_priority > CAIF_PRIO_MAX)
814 cf_sk->conn_req.priority = CAIF_PRIO_MAX;
815 else if (cf_sk->sk.sk_priority < CAIF_PRIO_MIN)
816 cf_sk->conn_req.priority = CAIF_PRIO_MIN;
817 else
818 cf_sk->conn_req.priority = cf_sk->sk.sk_priority;
819
820 /*ifindex = id of the interface.*/
821 cf_sk->conn_req.ifindex = cf_sk->sk.sk_bound_dev_if;
822
823 cf_sk->layer.receive = caif_sktrecv_cb;
824
825 err = caif_connect_client(net: sock_net(sk), conn_req: &cf_sk->conn_req,
826 client_layer: &cf_sk->layer, ifindex: &ifindex, headroom: &headroom, tailroom: &tailroom);
827
828 if (err < 0) {
829 cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
830 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
831 goto out;
832 }
833
834 err = -ENODEV;
835 rcu_read_lock();
836 dev = dev_get_by_index_rcu(net: sock_net(sk), ifindex);
837 if (!dev) {
838 rcu_read_unlock();
839 goto out;
840 }
841 cf_sk->headroom = LL_RESERVED_SPACE_EXTRA(dev, headroom);
842 mtu = dev->mtu;
843 rcu_read_unlock();
844
845 cf_sk->tailroom = tailroom;
846 cf_sk->maxframe = mtu - (headroom + tailroom);
847 if (cf_sk->maxframe < 1) {
848 pr_warn("CAIF Interface MTU too small (%d)\n", dev->mtu);
849 err = -ENODEV;
850 goto out;
851 }
852
853 err = -EINPROGRESS;
854wait_connect:
855
856 if (sk->sk_state != CAIF_CONNECTED && (flags & O_NONBLOCK))
857 goto out;
858
859 timeo = sock_sndtimeo(sk, noblock: flags & O_NONBLOCK);
860
861 release_sock(sk);
862 err = -ERESTARTSYS;
863 timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
864 sk->sk_state != CAIF_CONNECTING,
865 timeo);
866 lock_sock(sk);
867 if (timeo < 0)
868 goto out; /* -ERESTARTSYS */
869
870 err = -ETIMEDOUT;
871 if (timeo == 0 && sk->sk_state != CAIF_CONNECTED)
872 goto out;
873 if (sk->sk_state != CAIF_CONNECTED) {
874 sock->state = SS_UNCONNECTED;
875 err = sock_error(sk);
876 if (!err)
877 err = -ECONNREFUSED;
878 goto out;
879 }
880 sock->state = SS_CONNECTED;
881 err = 0;
882out:
883 release_sock(sk);
884 return err;
885}
886
887/*
888 * caif_release() - Disconnect a CAIF Socket
889 * Copied and modified af_irda.c:irda_release().
890 */
891static int caif_release(struct socket *sock)
892{
893 struct sock *sk = sock->sk;
894 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
895
896 if (!sk)
897 return 0;
898
899 set_tx_flow_off(cf_sk);
900
901 /*
902 * Ensure that packets are not queued after this point in time.
903 * caif_queue_rcv_skb checks SOCK_DEAD holding the queue lock,
904 * this ensures no packets when sock is dead.
905 */
906 spin_lock_bh(lock: &sk->sk_receive_queue.lock);
907 sock_set_flag(sk, flag: SOCK_DEAD);
908 spin_unlock_bh(lock: &sk->sk_receive_queue.lock);
909 sock->sk = NULL;
910
911 WARN_ON(IS_ERR(cf_sk->debugfs_socket_dir));
912 debugfs_remove_recursive(dentry: cf_sk->debugfs_socket_dir);
913
914 lock_sock(sk: &(cf_sk->sk));
915 sk->sk_state = CAIF_DISCONNECTED;
916 sk->sk_shutdown = SHUTDOWN_MASK;
917
918 caif_disconnect_client(net: sock_net(sk), client_layer: &cf_sk->layer);
919 cf_sk->sk.sk_socket->state = SS_DISCONNECTING;
920 wake_up_interruptible_poll(sk_sleep(sk), EPOLLERR|EPOLLHUP);
921
922 sock_orphan(sk);
923 sk_stream_kill_queues(sk: &cf_sk->sk);
924 release_sock(sk);
925 sock_put(sk);
926 return 0;
927}
928
929/* Copied from af_unix.c:unix_poll(), added CAIF tx_flow handling */
930static __poll_t caif_poll(struct file *file,
931 struct socket *sock, poll_table *wait)
932{
933 struct sock *sk = sock->sk;
934 __poll_t mask;
935 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
936
937 sock_poll_wait(filp: file, sock, p: wait);
938 mask = 0;
939
940 /* exceptional events? */
941 if (sk->sk_err)
942 mask |= EPOLLERR;
943 if (sk->sk_shutdown == SHUTDOWN_MASK)
944 mask |= EPOLLHUP;
945 if (sk->sk_shutdown & RCV_SHUTDOWN)
946 mask |= EPOLLRDHUP;
947
948 /* readable? */
949 if (!skb_queue_empty_lockless(list: &sk->sk_receive_queue) ||
950 (sk->sk_shutdown & RCV_SHUTDOWN))
951 mask |= EPOLLIN | EPOLLRDNORM;
952
953 /*
954 * we set writable also when the other side has shut down the
955 * connection. This prevents stuck sockets.
956 */
957 if (sock_writeable(sk) && tx_flow_is_on(cf_sk))
958 mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
959
960 return mask;
961}
962
963static const struct proto_ops caif_seqpacket_ops = {
964 .family = PF_CAIF,
965 .owner = THIS_MODULE,
966 .release = caif_release,
967 .bind = sock_no_bind,
968 .connect = caif_connect,
969 .socketpair = sock_no_socketpair,
970 .accept = sock_no_accept,
971 .getname = sock_no_getname,
972 .poll = caif_poll,
973 .ioctl = sock_no_ioctl,
974 .listen = sock_no_listen,
975 .shutdown = sock_no_shutdown,
976 .setsockopt = setsockopt,
977 .sendmsg = caif_seqpkt_sendmsg,
978 .recvmsg = caif_seqpkt_recvmsg,
979 .mmap = sock_no_mmap,
980};
981
982static const struct proto_ops caif_stream_ops = {
983 .family = PF_CAIF,
984 .owner = THIS_MODULE,
985 .release = caif_release,
986 .bind = sock_no_bind,
987 .connect = caif_connect,
988 .socketpair = sock_no_socketpair,
989 .accept = sock_no_accept,
990 .getname = sock_no_getname,
991 .poll = caif_poll,
992 .ioctl = sock_no_ioctl,
993 .listen = sock_no_listen,
994 .shutdown = sock_no_shutdown,
995 .setsockopt = setsockopt,
996 .sendmsg = caif_stream_sendmsg,
997 .recvmsg = caif_stream_recvmsg,
998 .mmap = sock_no_mmap,
999};
1000
1001/* This function is called when a socket is finally destroyed. */
1002static void caif_sock_destructor(struct sock *sk)
1003{
1004 struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
1005 caif_assert(!refcount_read(&sk->sk_wmem_alloc));
1006 caif_assert(sk_unhashed(sk));
1007 caif_assert(!sk->sk_socket);
1008 if (!sock_flag(sk, flag: SOCK_DEAD)) {
1009 pr_debug("Attempt to release alive CAIF socket: %p\n", sk);
1010 return;
1011 }
1012 sk_stream_kill_queues(sk: &cf_sk->sk);
1013 WARN_ON_ONCE(sk->sk_forward_alloc);
1014 caif_free_client(adap_layer: &cf_sk->layer);
1015}
1016
1017static int caif_create(struct net *net, struct socket *sock, int protocol,
1018 int kern)
1019{
1020 struct sock *sk = NULL;
1021 struct caifsock *cf_sk = NULL;
1022 static struct proto prot = {.name = "PF_CAIF",
1023 .owner = THIS_MODULE,
1024 .obj_size = sizeof(struct caifsock),
1025 .useroffset = offsetof(struct caifsock, conn_req.param),
1026 .usersize = sizeof_field(struct caifsock, conn_req.param)
1027 };
1028
1029 if (!capable(CAP_SYS_ADMIN) && !capable(CAP_NET_ADMIN))
1030 return -EPERM;
1031 /*
1032 * The sock->type specifies the socket type to use.
1033 * The CAIF socket is a packet stream in the sense
1034 * that it is packet based. CAIF trusts the reliability
1035 * of the link, no resending is implemented.
1036 */
1037 if (sock->type == SOCK_SEQPACKET)
1038 sock->ops = &caif_seqpacket_ops;
1039 else if (sock->type == SOCK_STREAM)
1040 sock->ops = &caif_stream_ops;
1041 else
1042 return -ESOCKTNOSUPPORT;
1043
1044 if (protocol < 0 || protocol >= CAIFPROTO_MAX)
1045 return -EPROTONOSUPPORT;
1046 /*
1047 * Set the socket state to unconnected. The socket state
1048 * is really not used at all in the net/core or socket.c but the
1049 * initialization makes sure that sock->state is not uninitialized.
1050 */
1051 sk = sk_alloc(net, PF_CAIF, GFP_KERNEL, prot: &prot, kern);
1052 if (!sk)
1053 return -ENOMEM;
1054
1055 cf_sk = container_of(sk, struct caifsock, sk);
1056
1057 /* Store the protocol */
1058 sk->sk_protocol = (unsigned char) protocol;
1059
1060 /* Initialize default priority for well-known cases */
1061 switch (protocol) {
1062 case CAIFPROTO_AT:
1063 sk->sk_priority = TC_PRIO_CONTROL;
1064 break;
1065 case CAIFPROTO_RFM:
1066 sk->sk_priority = TC_PRIO_INTERACTIVE_BULK;
1067 break;
1068 default:
1069 sk->sk_priority = TC_PRIO_BESTEFFORT;
1070 }
1071
1072 /*
1073 * Lock in order to try to stop someone from opening the socket
1074 * too early.
1075 */
1076 lock_sock(sk: &(cf_sk->sk));
1077
1078 /* Initialize the nozero default sock structure data. */
1079 sock_init_data(sock, sk);
1080 sk->sk_destruct = caif_sock_destructor;
1081
1082 mutex_init(&cf_sk->readlock); /* single task reading lock */
1083 cf_sk->layer.ctrlcmd = caif_ctrl_cb;
1084 cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
1085 cf_sk->sk.sk_state = CAIF_DISCONNECTED;
1086
1087 set_tx_flow_off(cf_sk);
1088 set_rx_flow_on(cf_sk);
1089
1090 /* Set default options on configuration */
1091 cf_sk->conn_req.link_selector = CAIF_LINK_LOW_LATENCY;
1092 cf_sk->conn_req.protocol = protocol;
1093 release_sock(sk: &cf_sk->sk);
1094 return 0;
1095}
1096
1097
1098static const struct net_proto_family caif_family_ops = {
1099 .family = PF_CAIF,
1100 .create = caif_create,
1101 .owner = THIS_MODULE,
1102};
1103
1104static int __init caif_sktinit_module(void)
1105{
1106 return sock_register(fam: &caif_family_ops);
1107}
1108
1109static void __exit caif_sktexit_module(void)
1110{
1111 sock_unregister(PF_CAIF);
1112}
1113module_init(caif_sktinit_module);
1114module_exit(caif_sktexit_module);
1115

source code of linux/net/caif/caif_socket.c