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

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