1	// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
2	/*
3	* bcm.c - Broadcast Manager to filter/send (cyclic) CAN content
4	*
5	* Copyright (c) 2002-2017 Volkswagen Group Electronic Research
6	* All rights reserved.
7	*
8	* Redistribution and use in source and binary forms, with or without
9	* modification, are permitted provided that the following conditions
10	* are met:
11	* 1. Redistributions of source code must retain the above copyright
12	* notice, this list of conditions and the following disclaimer.
13	* 2. Redistributions in binary form must reproduce the above copyright
14	* notice, this list of conditions and the following disclaimer in the
15	* documentation and/or other materials provided with the distribution.
16	* 3. Neither the name of Volkswagen nor the names of its contributors
17	* may be used to endorse or promote products derived from this software
18	* without specific prior written permission.
19	*
20	* Alternatively, provided that this notice is retained in full, this
21	* software may be distributed under the terms of the GNU General
22	* Public License ("GPL") version 2, in which case the provisions of the
23	* GPL apply INSTEAD OF those given above.
24	*
25	* The provided data structures and external interfaces from this code
26	* are not restricted to be used by modules with a GPL compatible license.
27	*
28	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
29	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
30	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
31	* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
32	* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
33	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
34	* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
35	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
36	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
37	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
38	* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
39	* DAMAGE.
40	*
41	*/
42
43	#include <linux/module.h>
44	#include <linux/init.h>
45	#include <linux/interrupt.h>
46	#include <linux/hrtimer.h>
47	#include <linux/list.h>
48	#include <linux/proc_fs.h>
49	#include <linux/seq_file.h>
50	#include <linux/uio.h>
51	#include <linux/net.h>
52	#include <linux/netdevice.h>
53	#include <linux/socket.h>
54	#include <linux/if_arp.h>
55	#include <linux/skbuff.h>
56	#include <linux/can.h>
57	#include <linux/can/core.h>
58	#include <linux/can/skb.h>
59	#include <linux/can/bcm.h>
60	#include <linux/slab.h>
61	#include <net/sock.h>
62	#include <net/net_namespace.h>
63
64	/*
65	* To send multiple CAN frame content within TX_SETUP or to filter
66	* CAN messages with multiplex index within RX_SETUP, the number of
67	* different filters is limited to 256 due to the one byte index value.
68	*/
69	#define MAX_NFRAMES 256
70
71	/* limit timers to 400 days for sending/timeouts */
72	#define BCM_TIMER_SEC_MAX (400 * 24 * 60 * 60)
73
74	/* use of last_frames[index].flags */
75	#define RX_RECV 0x40 /* received data for this element */
76	#define RX_THR 0x80 /* element not been sent due to throttle feature */
77	#define BCM_CAN_FLAGS_MASK 0x3F /* to clean private flags after usage */
78
79	/* get best masking value for can_rx_register() for a given single can_id */
80	#define REGMASK(id) ((id & CAN_EFF_FLAG) ? \
81	(CAN_EFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG) : \
82	(CAN_SFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG))
83
84	MODULE_DESCRIPTION("PF_CAN broadcast manager protocol");
85	MODULE_LICENSE("Dual BSD/GPL");
86	MODULE_AUTHOR("Oliver Hartkopp <oliver.hartkopp@volkswagen.de>");
87	MODULE_ALIAS("can-proto-2");
88
89	#define BCM_MIN_NAMELEN CAN_REQUIRED_SIZE(struct sockaddr_can, can_ifindex)
90
91	/*
92	* easy access to the first 64 bit of can(fd)_frame payload. cp->data is
93	* 64 bit aligned so the offset has to be multiples of 8 which is ensured
94	* by the only callers in bcm_rx_cmp_to_index() bcm_rx_handler().
95	*/
96	static inline u64 get_u64(const struct canfd_frame *cp, int offset)
97	{
98	return *(u64 *)(cp->data + offset);
99	}
100
101	struct bcm_op {
102	struct list_head list;
103	struct rcu_head rcu;
104	int ifindex;
105	canid_t can_id;
106	u32 flags;
107	unsigned long frames_abs, frames_filtered;
108	struct bcm_timeval ival1, ival2;
109	struct hrtimer timer, thrtimer;
110	ktime_t rx_stamp, kt_ival1, kt_ival2, kt_lastmsg;
111	int rx_ifindex;
112	int cfsiz;
113	u32 count;
114	u32 nframes;
115	u32 currframe;
116	/* void pointers to arrays of struct can[fd]_frame */
117	void *frames;
118	void *last_frames;
119	struct canfd_frame sframe;
120	struct canfd_frame last_sframe;
121	struct sock *sk;
122	struct net_device *rx_reg_dev;
123	};
124
125	struct bcm_sock {
126	struct sock sk;
127	int bound;
128	int ifindex;
129	struct list_head notifier;
130	struct list_head rx_ops;
131	struct list_head tx_ops;
132	unsigned long dropped_usr_msgs;
133	struct proc_dir_entry *bcm_proc_read;
134	char procname [32]; /* inode number in decimal with \0 */
135	};
136
137	static LIST_HEAD(bcm_notifier_list);
138	static DEFINE_SPINLOCK(bcm_notifier_lock);
139	static struct bcm_sock *bcm_busy_notifier;
140
141	static inline struct bcm_sock *bcm_sk(const struct sock *sk)
142	{
143	return (struct bcm_sock *)sk;
144	}
145
146	static inline ktime_t bcm_timeval_to_ktime(struct bcm_timeval tv)
147	{
148	return ktime_set(secs: tv.tv_sec, nsecs: tv.tv_usec * NSEC_PER_USEC);
149	}
150
151	/* check limitations for timeval provided by user */
152	static bool bcm_is_invalid_tv(struct bcm_msg_head *msg_head)
153	{
154	if ((msg_head->ival1.tv_sec < 0) ||
155	(msg_head->ival1.tv_sec > BCM_TIMER_SEC_MAX) ||
156	(msg_head->ival1.tv_usec < 0) ||
157	(msg_head->ival1.tv_usec >= USEC_PER_SEC) ||
158	(msg_head->ival2.tv_sec < 0) ||
159	(msg_head->ival2.tv_sec > BCM_TIMER_SEC_MAX) ||
160	(msg_head->ival2.tv_usec < 0) ||
161	(msg_head->ival2.tv_usec >= USEC_PER_SEC))
162	return true;
163
164	return false;
165	}
166
167	#define CFSIZ(flags) ((flags & CAN_FD_FRAME) ? CANFD_MTU : CAN_MTU)
168	#define OPSIZ sizeof(struct bcm_op)
169	#define MHSIZ sizeof(struct bcm_msg_head)
170
171	/*
172	* procfs functions
173	*/
174	#if IS_ENABLED(CONFIG_PROC_FS)
175	static char *bcm_proc_getifname(struct net *net, char *result, int ifindex)
176	{
177	struct net_device *dev;
178
179	if (!ifindex)
180	return "any";
181
182	rcu_read_lock();
183	dev = dev_get_by_index_rcu(net, ifindex);
184	if (dev)
185	strcpy(p: result, q: dev->name);
186	else
187	strcpy(p: result, q: "???");
188	rcu_read_unlock();
189
190	return result;
191	}
192
193	static int bcm_proc_show(struct seq_file *m, void *v)
194	{
195	char ifname[IFNAMSIZ];
196	struct net *net = m->private;
197	struct sock *sk = (struct sock *)pde_data(inode: m->file->f_inode);
198	struct bcm_sock *bo = bcm_sk(sk);
199	struct bcm_op *op;
200
201	seq_printf(m, fmt: ">>> socket %pK", sk->sk_socket);
202	seq_printf(m, fmt: " / sk %pK", sk);
203	seq_printf(m, fmt: " / bo %pK", bo);
204	seq_printf(m, fmt: " / dropped %lu", bo->dropped_usr_msgs);
205	seq_printf(m, fmt: " / bound %s", bcm_proc_getifname(net, result: ifname, ifindex: bo->ifindex));
206	seq_printf(m, fmt: " <<<\n");
207
208	list_for_each_entry(op, &bo->rx_ops, list) {
209
210	unsigned long reduction;
211
212	/* print only active entries & prevent division by zero */
213	if (!op->frames_abs)
214	continue;
215
216	seq_printf(m, fmt: "rx_op: %03X %-5s ", op->can_id,
217	bcm_proc_getifname(net, result: ifname, ifindex: op->ifindex));
218
219	if (op->flags & CAN_FD_FRAME)
220	seq_printf(m, fmt: "(%u)", op->nframes);
221	else
222	seq_printf(m, fmt: "[%u]", op->nframes);
223
224	seq_printf(m, fmt: "%c ", (op->flags & RX_CHECK_DLC) ? 'd' : ' ');
225
226	if (op->kt_ival1)
227	seq_printf(m, fmt: "timeo=%lld ",
228	(long long)ktime_to_us(kt: op->kt_ival1));
229
230	if (op->kt_ival2)
231	seq_printf(m, fmt: "thr=%lld ",
232	(long long)ktime_to_us(kt: op->kt_ival2));
233
234	seq_printf(m, fmt: "# recv %ld (%ld) => reduction: ",
235	op->frames_filtered, op->frames_abs);
236
237	reduction = 100 - (op->frames_filtered * 100) / op->frames_abs;
238
239	seq_printf(m, fmt: "%s%ld%%\n",
240	(reduction == 100) ? "near " : "", reduction);
241	}
242
243	list_for_each_entry(op, &bo->tx_ops, list) {
244
245	seq_printf(m, fmt: "tx_op: %03X %s ", op->can_id,
246	bcm_proc_getifname(net, result: ifname, ifindex: op->ifindex));
247
248	if (op->flags & CAN_FD_FRAME)
249	seq_printf(m, fmt: "(%u) ", op->nframes);
250	else
251	seq_printf(m, fmt: "[%u] ", op->nframes);
252
253	if (op->kt_ival1)
254	seq_printf(m, fmt: "t1=%lld ",
255	(long long)ktime_to_us(kt: op->kt_ival1));
256
257	if (op->kt_ival2)
258	seq_printf(m, fmt: "t2=%lld ",
259	(long long)ktime_to_us(kt: op->kt_ival2));
260
261	seq_printf(m, fmt: "# sent %ld\n", op->frames_abs);
262	}
263	seq_putc(m, c: '\n');
264	return 0;
265	}
266	#endif /* CONFIG_PROC_FS */
267
268	/*
269	* bcm_can_tx - send the (next) CAN frame to the appropriate CAN interface
270	* of the given bcm tx op
271	*/
272	static void bcm_can_tx(struct bcm_op *op)
273	{
274	struct sk_buff *skb;
275	struct net_device *dev;
276	struct canfd_frame *cf = op->frames + op->cfsiz * op->currframe;
277	int err;
278
279	/* no target device? => exit */
280	if (!op->ifindex)
281	return;
282
283	dev = dev_get_by_index(net: sock_net(sk: op->sk), ifindex: op->ifindex);
284	if (!dev) {
285	/* RFC: should this bcm_op remove itself here? */
286	return;
287	}
288
289	skb = alloc_skb(size: op->cfsiz + sizeof(struct can_skb_priv), priority: gfp_any());
290	if (!skb)
291	goto out;
292
293	can_skb_reserve(skb);
294	can_skb_prv(skb)->ifindex = dev->ifindex;
295	can_skb_prv(skb)->skbcnt = 0;
296
297	skb_put_data(skb, data: cf, len: op->cfsiz);
298
299	/* send with loopback */
300	skb->dev = dev;
301	can_skb_set_owner(skb, sk: op->sk);
302	err = can_send(skb, loop: 1);
303	if (!err)
304	op->frames_abs++;
305
306	op->currframe++;
307
308	/* reached last frame? */
309	if (op->currframe >= op->nframes)
310	op->currframe = 0;
311	out:
312	dev_put(dev);
313	}
314
315	/*
316	* bcm_send_to_user - send a BCM message to the userspace
317	* (consisting of bcm_msg_head + x CAN frames)
318	*/
319	static void bcm_send_to_user(struct bcm_op *op, struct bcm_msg_head *head,
320	struct canfd_frame *frames, int has_timestamp)
321	{
322	struct sk_buff *skb;
323	struct canfd_frame *firstframe;
324	struct sockaddr_can *addr;
325	struct sock *sk = op->sk;
326	unsigned int datalen = head->nframes * op->cfsiz;
327	int err;
328
329	skb = alloc_skb(size: sizeof(*head) + datalen, priority: gfp_any());
330	if (!skb)
331	return;
332
333	skb_put_data(skb, data: head, len: sizeof(*head));
334
335	if (head->nframes) {
336	/* CAN frames starting here */
337	firstframe = (struct canfd_frame *)skb_tail_pointer(skb);
338
339	skb_put_data(skb, data: frames, len: datalen);
340
341	/*
342	* the BCM uses the flags-element of the canfd_frame
343	* structure for internal purposes. This is only
344	* relevant for updates that are generated by the
345	* BCM, where nframes is 1
346	*/
347	if (head->nframes == 1)
348	firstframe->flags &= BCM_CAN_FLAGS_MASK;
349	}
350
351	if (has_timestamp) {
352	/* restore rx timestamp */
353	skb->tstamp = op->rx_stamp;
354	}
355
356	/*
357	* Put the datagram to the queue so that bcm_recvmsg() can
358	* get it from there. We need to pass the interface index to
359	* bcm_recvmsg(). We pass a whole struct sockaddr_can in skb->cb
360	* containing the interface index.
361	*/
362
363	sock_skb_cb_check_size(sizeof(struct sockaddr_can));
364	addr = (struct sockaddr_can *)skb->cb;
365	memset(addr, 0, sizeof(*addr));
366	addr->can_family = AF_CAN;
367	addr->can_ifindex = op->rx_ifindex;
368
369	err = sock_queue_rcv_skb(sk, skb);
370	if (err < 0) {
371	struct bcm_sock *bo = bcm_sk(sk);
372
373	kfree_skb(skb);
374	/* don't care about overflows in this statistic */
375	bo->dropped_usr_msgs++;
376	}
377	}
378
379	static bool bcm_tx_set_expiry(struct bcm_op *op, struct hrtimer *hrt)
380	{
381	ktime_t ival;
382
383	if (op->kt_ival1 && op->count)
384	ival = op->kt_ival1;
385	else if (op->kt_ival2)
386	ival = op->kt_ival2;
387	else
388	return false;
389
390	hrtimer_set_expires(timer: hrt, ktime_add(ktime_get(), ival));
391	return true;
392	}
393
394	static void bcm_tx_start_timer(struct bcm_op *op)
395	{
396	if (bcm_tx_set_expiry(op, hrt: &op->timer))
397	hrtimer_start_expires(timer: &op->timer, mode: HRTIMER_MODE_ABS_SOFT);
398	}
399
400	/* bcm_tx_timeout_handler - performs cyclic CAN frame transmissions */
401	static enum hrtimer_restart bcm_tx_timeout_handler(struct hrtimer *hrtimer)
402	{
403	struct bcm_op *op = container_of(hrtimer, struct bcm_op, timer);
404	struct bcm_msg_head msg_head;
405
406	if (op->kt_ival1 && (op->count > 0)) {
407	op->count--;
408	if (!op->count && (op->flags & TX_COUNTEVT)) {
409
410	/* create notification to user */
411	memset(&msg_head, 0, sizeof(msg_head));
412	msg_head.opcode = TX_EXPIRED;
413	msg_head.flags = op->flags;
414	msg_head.count = op->count;
415	msg_head.ival1 = op->ival1;
416	msg_head.ival2 = op->ival2;
417	msg_head.can_id = op->can_id;
418	msg_head.nframes = 0;
419
420	bcm_send_to_user(op, head: &msg_head, NULL, has_timestamp: 0);
421	}
422	bcm_can_tx(op);
423
424	} else if (op->kt_ival2) {
425	bcm_can_tx(op);
426	}
427
428	return bcm_tx_set_expiry(op, hrt: &op->timer) ?
429	HRTIMER_RESTART : HRTIMER_NORESTART;
430	}
431
432	/*
433	* bcm_rx_changed - create a RX_CHANGED notification due to changed content
434	*/
435	static void bcm_rx_changed(struct bcm_op *op, struct canfd_frame *data)
436	{
437	struct bcm_msg_head head;
438
439	/* update statistics */
440	op->frames_filtered++;
441
442	/* prevent statistics overflow */
443	if (op->frames_filtered > ULONG_MAX/100)
444	op->frames_filtered = op->frames_abs = 0;
445
446	/* this element is not throttled anymore */
447	data->flags &= (BCM_CAN_FLAGS_MASK|RX_RECV);
448
449	memset(&head, 0, sizeof(head));
450	head.opcode = RX_CHANGED;
451	head.flags = op->flags;
452	head.count = op->count;
453	head.ival1 = op->ival1;
454	head.ival2 = op->ival2;
455	head.can_id = op->can_id;
456	head.nframes = 1;
457
458	bcm_send_to_user(op, head: &head, frames: data, has_timestamp: 1);
459	}
460
461	/*
462	* bcm_rx_update_and_send - process a detected relevant receive content change
463	* 1. update the last received data
464	* 2. send a notification to the user (if possible)
465	*/
466	static void bcm_rx_update_and_send(struct bcm_op *op,
467	struct canfd_frame *lastdata,
468	const struct canfd_frame *rxdata)
469	{
470	memcpy(lastdata, rxdata, op->cfsiz);
471
472	/* mark as used and throttled by default */
473	lastdata->flags |= (RX_RECV|RX_THR);
474
475	/* throttling mode inactive ? */
476	if (!op->kt_ival2) {
477	/* send RX_CHANGED to the user immediately */
478	bcm_rx_changed(op, data: lastdata);
479	return;
480	}
481
482	/* with active throttling timer we are just done here */
483	if (hrtimer_active(timer: &op->thrtimer))
484	return;
485
486	/* first reception with enabled throttling mode */
487	if (!op->kt_lastmsg)
488	goto rx_changed_settime;
489
490	/* got a second frame inside a potential throttle period? */
491	if (ktime_us_delta(later: ktime_get(), earlier: op->kt_lastmsg) <
492	ktime_to_us(kt: op->kt_ival2)) {
493	/* do not send the saved data - only start throttle timer */
494	hrtimer_start(timer: &op->thrtimer,
495	ktime_add(op->kt_lastmsg, op->kt_ival2),
496	mode: HRTIMER_MODE_ABS_SOFT);
497	return;
498	}
499
500	/* the gap was that big, that throttling was not needed here */
501	rx_changed_settime:
502	bcm_rx_changed(op, data: lastdata);
503	op->kt_lastmsg = ktime_get();
504	}
505
506	/*
507	* bcm_rx_cmp_to_index - (bit)compares the currently received data to formerly
508	* received data stored in op->last_frames[]
509	*/
510	static void bcm_rx_cmp_to_index(struct bcm_op *op, unsigned int index,
511	const struct canfd_frame *rxdata)
512	{
513	struct canfd_frame *cf = op->frames + op->cfsiz * index;
514	struct canfd_frame *lcf = op->last_frames + op->cfsiz * index;
515	int i;
516
517	/*
518	* no one uses the MSBs of flags for comparison,
519	* so we use it here to detect the first time of reception
520	*/
521
522	if (!(lcf->flags & RX_RECV)) {
523	/* received data for the first time => send update to user */
524	bcm_rx_update_and_send(op, lastdata: lcf, rxdata);
525	return;
526	}
527
528	/* do a real check in CAN frame data section */
529	for (i = 0; i < rxdata->len; i += 8) {
530	if ((get_u64(cp: cf, offset: i) & get_u64(cp: rxdata, offset: i)) !=
531	(get_u64(cp: cf, offset: i) & get_u64(cp: lcf, offset: i))) {
532	bcm_rx_update_and_send(op, lastdata: lcf, rxdata);
533	return;
534	}
535	}
536
537	if (op->flags & RX_CHECK_DLC) {
538	/* do a real check in CAN frame length */
539	if (rxdata->len != lcf->len) {
540	bcm_rx_update_and_send(op, lastdata: lcf, rxdata);
541	return;
542	}
543	}
544	}
545
546	/*
547	* bcm_rx_starttimer - enable timeout monitoring for CAN frame reception
548	*/
549	static void bcm_rx_starttimer(struct bcm_op *op)
550	{
551	if (op->flags & RX_NO_AUTOTIMER)
552	return;
553
554	if (op->kt_ival1)
555	hrtimer_start(timer: &op->timer, tim: op->kt_ival1, mode: HRTIMER_MODE_REL_SOFT);
556	}
557
558	/* bcm_rx_timeout_handler - when the (cyclic) CAN frame reception timed out */
559	static enum hrtimer_restart bcm_rx_timeout_handler(struct hrtimer *hrtimer)
560	{
561	struct bcm_op *op = container_of(hrtimer, struct bcm_op, timer);
562	struct bcm_msg_head msg_head;
563
564	/* if user wants to be informed, when cyclic CAN-Messages come back */
565	if ((op->flags & RX_ANNOUNCE_RESUME) && op->last_frames) {
566	/* clear received CAN frames to indicate 'nothing received' */
567	memset(op->last_frames, 0, op->nframes * op->cfsiz);
568	}
569
570	/* create notification to user */
571	memset(&msg_head, 0, sizeof(msg_head));
572	msg_head.opcode = RX_TIMEOUT;
573	msg_head.flags = op->flags;
574	msg_head.count = op->count;
575	msg_head.ival1 = op->ival1;
576	msg_head.ival2 = op->ival2;
577	msg_head.can_id = op->can_id;
578	msg_head.nframes = 0;
579
580	bcm_send_to_user(op, head: &msg_head, NULL, has_timestamp: 0);
581
582	return HRTIMER_NORESTART;
583	}
584
585	/*
586	* bcm_rx_do_flush - helper for bcm_rx_thr_flush
587	*/
588	static inline int bcm_rx_do_flush(struct bcm_op *op, unsigned int index)
589	{
590	struct canfd_frame *lcf = op->last_frames + op->cfsiz * index;
591
592	if ((op->last_frames) && (lcf->flags & RX_THR)) {
593	bcm_rx_changed(op, data: lcf);
594	return 1;
595	}
596	return 0;
597	}
598
599	/*
600	* bcm_rx_thr_flush - Check for throttled data and send it to the userspace
601	*/
602	static int bcm_rx_thr_flush(struct bcm_op *op)
603	{
604	int updated = 0;
605
606	if (op->nframes > 1) {
607	unsigned int i;
608
609	/* for MUX filter we start at index 1 */
610	for (i = 1; i < op->nframes; i++)
611	updated += bcm_rx_do_flush(op, index: i);
612
613	} else {
614	/* for RX_FILTER_ID and simple filter */
615	updated += bcm_rx_do_flush(op, index: 0);
616	}
617
618	return updated;
619	}
620
621	/*
622	* bcm_rx_thr_handler - the time for blocked content updates is over now:
623	* Check for throttled data and send it to the userspace
624	*/
625	static enum hrtimer_restart bcm_rx_thr_handler(struct hrtimer *hrtimer)
626	{
627	struct bcm_op *op = container_of(hrtimer, struct bcm_op, thrtimer);
628
629	if (bcm_rx_thr_flush(op)) {
630	hrtimer_forward_now(timer: hrtimer, interval: op->kt_ival2);
631	return HRTIMER_RESTART;
632	} else {
633	/* rearm throttle handling */
634	op->kt_lastmsg = 0;
635	return HRTIMER_NORESTART;
636	}
637	}
638
639	/*
640	* bcm_rx_handler - handle a CAN frame reception
641	*/
642	static void bcm_rx_handler(struct sk_buff *skb, void *data)
643	{
644	struct bcm_op *op = (struct bcm_op *)data;
645	const struct canfd_frame *rxframe = (struct canfd_frame *)skb->data;
646	unsigned int i;
647
648	if (op->can_id != rxframe->can_id)
649	return;
650
651	/* make sure to handle the correct frame type (CAN / CAN FD) */
652	if (op->flags & CAN_FD_FRAME) {
653	if (!can_is_canfd_skb(skb))
654	return;
655	} else {
656	if (!can_is_can_skb(skb))
657	return;
658	}
659
660	/* disable timeout */
661	hrtimer_cancel(timer: &op->timer);
662
663	/* save rx timestamp */
664	op->rx_stamp = skb->tstamp;
665	/* save originator for recvfrom() */
666	op->rx_ifindex = skb->dev->ifindex;
667	/* update statistics */
668	op->frames_abs++;
669
670	if (op->flags & RX_RTR_FRAME) {
671	/* send reply for RTR-request (placed in op->frames[0]) */
672	bcm_can_tx(op);
673	return;
674	}
675
676	if (op->flags & RX_FILTER_ID) {
677	/* the easiest case */
678	bcm_rx_update_and_send(op, lastdata: op->last_frames, rxdata: rxframe);
679	goto rx_starttimer;
680	}
681
682	if (op->nframes == 1) {
683	/* simple compare with index 0 */
684	bcm_rx_cmp_to_index(op, index: 0, rxdata: rxframe);
685	goto rx_starttimer;
686	}
687
688	if (op->nframes > 1) {
689	/*
690	* multiplex compare
691	*
692	* find the first multiplex mask that fits.
693	* Remark: The MUX-mask is stored in index 0 - but only the
694	* first 64 bits of the frame data[] are relevant (CAN FD)
695	*/
696
697	for (i = 1; i < op->nframes; i++) {
698	if ((get_u64(cp: op->frames, offset: 0) & get_u64(cp: rxframe, offset: 0)) ==
699	(get_u64(cp: op->frames, offset: 0) &
700	get_u64(cp: op->frames + op->cfsiz * i, offset: 0))) {
701	bcm_rx_cmp_to_index(op, index: i, rxdata: rxframe);
702	break;
703	}
704	}
705	}
706
707	rx_starttimer:
708	bcm_rx_starttimer(op);
709	}
710
711	/*
712	* helpers for bcm_op handling: find & delete bcm [rx|tx] op elements
713	*/
714	static struct bcm_op *bcm_find_op(struct list_head *ops,
715	struct bcm_msg_head *mh, int ifindex)
716	{
717	struct bcm_op *op;
718
719	list_for_each_entry(op, ops, list) {
720	if ((op->can_id == mh->can_id) && (op->ifindex == ifindex) &&
721	(op->flags & CAN_FD_FRAME) == (mh->flags & CAN_FD_FRAME))
722	return op;
723	}
724
725	return NULL;
726	}
727
728	static void bcm_free_op_rcu(struct rcu_head *rcu_head)
729	{
730	struct bcm_op *op = container_of(rcu_head, struct bcm_op, rcu);
731
732	if ((op->frames) && (op->frames != &op->sframe))
733	kfree(objp: op->frames);
734
735	if ((op->last_frames) && (op->last_frames != &op->last_sframe))
736	kfree(objp: op->last_frames);
737
738	kfree(objp: op);
739	}
740
741	static void bcm_remove_op(struct bcm_op *op)
742	{
743	hrtimer_cancel(timer: &op->timer);
744	hrtimer_cancel(timer: &op->thrtimer);
745
746	call_rcu(head: &op->rcu, func: bcm_free_op_rcu);
747	}
748
749	static void bcm_rx_unreg(struct net_device *dev, struct bcm_op *op)
750	{
751	if (op->rx_reg_dev == dev) {
752	can_rx_unregister(net: dev_net(dev), dev, can_id: op->can_id,
753	REGMASK(op->can_id), func: bcm_rx_handler, data: op);
754
755	/* mark as removed subscription */
756	op->rx_reg_dev = NULL;
757	} else
758	printk(KERN_ERR "can-bcm: bcm_rx_unreg: registered device "
759	"mismatch %p %p\n", op->rx_reg_dev, dev);
760	}
761
762	/*
763	* bcm_delete_rx_op - find and remove a rx op (returns number of removed ops)
764	*/
765	static int bcm_delete_rx_op(struct list_head *ops, struct bcm_msg_head *mh,
766	int ifindex)
767	{
768	struct bcm_op *op, *n;
769
770	list_for_each_entry_safe(op, n, ops, list) {
771	if ((op->can_id == mh->can_id) && (op->ifindex == ifindex) &&
772	(op->flags & CAN_FD_FRAME) == (mh->flags & CAN_FD_FRAME)) {
773
774	/* disable automatic timer on frame reception */
775	op->flags |= RX_NO_AUTOTIMER;
776
777	/*
778	* Don't care if we're bound or not (due to netdev
779	* problems) can_rx_unregister() is always a save
780	* thing to do here.
781	*/
782	if (op->ifindex) {
783	/*
784	* Only remove subscriptions that had not
785	* been removed due to NETDEV_UNREGISTER
786	* in bcm_notifier()
787	*/
788	if (op->rx_reg_dev) {
789	struct net_device *dev;
790
791	dev = dev_get_by_index(net: sock_net(sk: op->sk),
792	ifindex: op->ifindex);
793	if (dev) {
794	bcm_rx_unreg(dev, op);
795	dev_put(dev);
796	}
797	}
798	} else
799	can_rx_unregister(net: sock_net(sk: op->sk), NULL,
800	can_id: op->can_id,
801	REGMASK(op->can_id),
802	func: bcm_rx_handler, data: op);
803
804	list_del(entry: &op->list);
805	bcm_remove_op(op);
806	return 1; /* done */
807	}
808	}
809
810	return 0; /* not found */
811	}
812
813	/*
814	* bcm_delete_tx_op - find and remove a tx op (returns number of removed ops)
815	*/
816	static int bcm_delete_tx_op(struct list_head *ops, struct bcm_msg_head *mh,
817	int ifindex)
818	{
819	struct bcm_op *op, *n;
820
821	list_for_each_entry_safe(op, n, ops, list) {
822	if ((op->can_id == mh->can_id) && (op->ifindex == ifindex) &&
823	(op->flags & CAN_FD_FRAME) == (mh->flags & CAN_FD_FRAME)) {
824	list_del(entry: &op->list);
825	bcm_remove_op(op);
826	return 1; /* done */
827	}
828	}
829
830	return 0; /* not found */
831	}
832
833	/*
834	* bcm_read_op - read out a bcm_op and send it to the user (for bcm_sendmsg)
835	*/
836	static int bcm_read_op(struct list_head *ops, struct bcm_msg_head *msg_head,
837	int ifindex)
838	{
839	struct bcm_op *op = bcm_find_op(ops, mh: msg_head, ifindex);
840
841	if (!op)
842	return -EINVAL;
843
844	/* put current values into msg_head */
845	msg_head->flags = op->flags;
846	msg_head->count = op->count;
847	msg_head->ival1 = op->ival1;
848	msg_head->ival2 = op->ival2;
849	msg_head->nframes = op->nframes;
850
851	bcm_send_to_user(op, head: msg_head, frames: op->frames, has_timestamp: 0);
852
853	return MHSIZ;
854	}
855
856	/*
857	* bcm_tx_setup - create or update a bcm tx op (for bcm_sendmsg)
858	*/
859	static int bcm_tx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
860	int ifindex, struct sock *sk)
861	{
862	struct bcm_sock *bo = bcm_sk(sk);
863	struct bcm_op *op;
864	struct canfd_frame *cf;
865	unsigned int i;
866	int err;
867
868	/* we need a real device to send frames */
869	if (!ifindex)
870	return -ENODEV;
871
872	/* check nframes boundaries - we need at least one CAN frame */
873	if (msg_head->nframes < 1 || msg_head->nframes > MAX_NFRAMES)
874	return -EINVAL;
875
876	/* check timeval limitations */
877	if ((msg_head->flags & SETTIMER) && bcm_is_invalid_tv(msg_head))
878	return -EINVAL;
879
880	/* check the given can_id */
881	op = bcm_find_op(ops: &bo->tx_ops, mh: msg_head, ifindex);
882	if (op) {
883	/* update existing BCM operation */
884
885	/*
886	* Do we need more space for the CAN frames than currently
887	* allocated? -> This is a _really_ unusual use-case and
888	* therefore (complexity / locking) it is not supported.
889	*/
890	if (msg_head->nframes > op->nframes)
891	return -E2BIG;
892
893	/* update CAN frames content */
894	for (i = 0; i < msg_head->nframes; i++) {
895
896	cf = op->frames + op->cfsiz * i;
897	err = memcpy_from_msg(data: (u8 *)cf, msg, len: op->cfsiz);
898
899	if (op->flags & CAN_FD_FRAME) {
900	if (cf->len > 64)
901	err = -EINVAL;
902	} else {
903	if (cf->len > 8)
904	err = -EINVAL;
905	}
906
907	if (err < 0)
908	return err;
909
910	if (msg_head->flags & TX_CP_CAN_ID) {
911	/* copy can_id into frame */
912	cf->can_id = msg_head->can_id;
913	}
914	}
915	op->flags = msg_head->flags;
916
917	} else {
918	/* insert new BCM operation for the given can_id */
919
920	op = kzalloc(OPSIZ, GFP_KERNEL);
921	if (!op)
922	return -ENOMEM;
923
924	op->can_id = msg_head->can_id;
925	op->cfsiz = CFSIZ(msg_head->flags);
926	op->flags = msg_head->flags;
927
928	/* create array for CAN frames and copy the data */
929	if (msg_head->nframes > 1) {
930	op->frames = kmalloc_array(n: msg_head->nframes,
931	size: op->cfsiz,
932	GFP_KERNEL);
933	if (!op->frames) {
934	kfree(objp: op);
935	return -ENOMEM;
936	}
937	} else
938	op->frames = &op->sframe;
939
940	for (i = 0; i < msg_head->nframes; i++) {
941
942	cf = op->frames + op->cfsiz * i;
943	err = memcpy_from_msg(data: (u8 *)cf, msg, len: op->cfsiz);
944	if (err < 0)
945	goto free_op;
946
947	if (op->flags & CAN_FD_FRAME) {
948	if (cf->len > 64)
949	err = -EINVAL;
950	} else {
951	if (cf->len > 8)
952	err = -EINVAL;
953	}
954
955	if (err < 0)
956	goto free_op;
957
958	if (msg_head->flags & TX_CP_CAN_ID) {
959	/* copy can_id into frame */
960	cf->can_id = msg_head->can_id;
961	}
962	}
963
964	/* tx_ops never compare with previous received messages */
965	op->last_frames = NULL;
966
967	/* bcm_can_tx / bcm_tx_timeout_handler needs this */
968	op->sk = sk;
969	op->ifindex = ifindex;
970
971	/* initialize uninitialized (kzalloc) structure */
972	hrtimer_init(timer: &op->timer, CLOCK_MONOTONIC,
973	mode: HRTIMER_MODE_REL_SOFT);
974	op->timer.function = bcm_tx_timeout_handler;
975
976	/* currently unused in tx_ops */
977	hrtimer_init(timer: &op->thrtimer, CLOCK_MONOTONIC,
978	mode: HRTIMER_MODE_REL_SOFT);
979
980	/* add this bcm_op to the list of the tx_ops */
981	list_add(new: &op->list, head: &bo->tx_ops);
982
983	} /* if ((op = bcm_find_op(&bo->tx_ops, msg_head->can_id, ifindex))) */
984
985	if (op->nframes != msg_head->nframes) {
986	op->nframes = msg_head->nframes;
987	/* start multiple frame transmission with index 0 */
988	op->currframe = 0;
989	}
990
991	/* check flags */
992
993	if (op->flags & TX_RESET_MULTI_IDX) {
994	/* start multiple frame transmission with index 0 */
995	op->currframe = 0;
996	}
997
998	if (op->flags & SETTIMER) {
999	/* set timer values */
1000	op->count = msg_head->count;
1001	op->ival1 = msg_head->ival1;
1002	op->ival2 = msg_head->ival2;
1003	op->kt_ival1 = bcm_timeval_to_ktime(tv: msg_head->ival1);
1004	op->kt_ival2 = bcm_timeval_to_ktime(tv: msg_head->ival2);
1005
1006	/* disable an active timer due to zero values? */
1007	if (!op->kt_ival1 && !op->kt_ival2)
1008	hrtimer_cancel(timer: &op->timer);
1009	}
1010
1011	if (op->flags & STARTTIMER) {
1012	hrtimer_cancel(timer: &op->timer);
1013	/* spec: send CAN frame when starting timer */
1014	op->flags |= TX_ANNOUNCE;
1015	}
1016
1017	if (op->flags & TX_ANNOUNCE) {
1018	bcm_can_tx(op);
1019	if (op->count)
1020	op->count--;
1021	}
1022
1023	if (op->flags & STARTTIMER)
1024	bcm_tx_start_timer(op);
1025
1026	return msg_head->nframes * op->cfsiz + MHSIZ;
1027
1028	free_op:
1029	if (op->frames != &op->sframe)
1030	kfree(objp: op->frames);
1031	kfree(objp: op);
1032	return err;
1033	}
1034
1035	/*
1036	* bcm_rx_setup - create or update a bcm rx op (for bcm_sendmsg)
1037	*/
1038	static int bcm_rx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
1039	int ifindex, struct sock *sk)
1040	{
1041	struct bcm_sock *bo = bcm_sk(sk);
1042	struct bcm_op *op;
1043	int do_rx_register;
1044	int err = 0;
1045
1046	if ((msg_head->flags & RX_FILTER_ID) || (!(msg_head->nframes))) {
1047	/* be robust against wrong usage ... */
1048	msg_head->flags |= RX_FILTER_ID;
1049	/* ignore trailing garbage */
1050	msg_head->nframes = 0;
1051	}
1052
1053	/* the first element contains the mux-mask => MAX_NFRAMES + 1 */
1054	if (msg_head->nframes > MAX_NFRAMES + 1)
1055	return -EINVAL;
1056
1057	if ((msg_head->flags & RX_RTR_FRAME) &&
1058	((msg_head->nframes != 1) ||
1059	(!(msg_head->can_id & CAN_RTR_FLAG))))
1060	return -EINVAL;
1061
1062	/* check timeval limitations */
1063	if ((msg_head->flags & SETTIMER) && bcm_is_invalid_tv(msg_head))
1064	return -EINVAL;
1065
1066	/* check the given can_id */
1067	op = bcm_find_op(ops: &bo->rx_ops, mh: msg_head, ifindex);
1068	if (op) {
1069	/* update existing BCM operation */
1070
1071	/*
1072	* Do we need more space for the CAN frames than currently
1073	* allocated? -> This is a _really_ unusual use-case and
1074	* therefore (complexity / locking) it is not supported.
1075	*/
1076	if (msg_head->nframes > op->nframes)
1077	return -E2BIG;
1078
1079	if (msg_head->nframes) {
1080	/* update CAN frames content */
1081	err = memcpy_from_msg(data: op->frames, msg,
1082	len: msg_head->nframes * op->cfsiz);
1083	if (err < 0)
1084	return err;
1085
1086	/* clear last_frames to indicate 'nothing received' */
1087	memset(op->last_frames, 0, msg_head->nframes * op->cfsiz);
1088	}
1089
1090	op->nframes = msg_head->nframes;
1091	op->flags = msg_head->flags;
1092
1093	/* Only an update -> do not call can_rx_register() */
1094	do_rx_register = 0;
1095
1096	} else {
1097	/* insert new BCM operation for the given can_id */
1098	op = kzalloc(OPSIZ, GFP_KERNEL);
1099	if (!op)
1100	return -ENOMEM;
1101
1102	op->can_id = msg_head->can_id;
1103	op->nframes = msg_head->nframes;
1104	op->cfsiz = CFSIZ(msg_head->flags);
1105	op->flags = msg_head->flags;
1106
1107	if (msg_head->nframes > 1) {
1108	/* create array for CAN frames and copy the data */
1109	op->frames = kmalloc_array(n: msg_head->nframes,
1110	size: op->cfsiz,
1111	GFP_KERNEL);
1112	if (!op->frames) {
1113	kfree(objp: op);
1114	return -ENOMEM;
1115	}
1116
1117	/* create and init array for received CAN frames */
1118	op->last_frames = kcalloc(n: msg_head->nframes,
1119	size: op->cfsiz,
1120	GFP_KERNEL);
1121	if (!op->last_frames) {
1122	kfree(objp: op->frames);
1123	kfree(objp: op);
1124	return -ENOMEM;
1125	}
1126
1127	} else {
1128	op->frames = &op->sframe;
1129	op->last_frames = &op->last_sframe;
1130	}
1131
1132	if (msg_head->nframes) {
1133	err = memcpy_from_msg(data: op->frames, msg,
1134	len: msg_head->nframes * op->cfsiz);
1135	if (err < 0) {
1136	if (op->frames != &op->sframe)
1137	kfree(objp: op->frames);
1138	if (op->last_frames != &op->last_sframe)
1139	kfree(objp: op->last_frames);
1140	kfree(objp: op);
1141	return err;
1142	}
1143	}
1144
1145	/* bcm_can_tx / bcm_tx_timeout_handler needs this */
1146	op->sk = sk;
1147	op->ifindex = ifindex;
1148
1149	/* ifindex for timeout events w/o previous frame reception */
1150	op->rx_ifindex = ifindex;
1151
1152	/* initialize uninitialized (kzalloc) structure */
1153	hrtimer_init(timer: &op->timer, CLOCK_MONOTONIC,
1154	mode: HRTIMER_MODE_REL_SOFT);
1155	op->timer.function = bcm_rx_timeout_handler;
1156
1157	hrtimer_init(timer: &op->thrtimer, CLOCK_MONOTONIC,
1158	mode: HRTIMER_MODE_REL_SOFT);
1159	op->thrtimer.function = bcm_rx_thr_handler;
1160
1161	/* add this bcm_op to the list of the rx_ops */
1162	list_add(new: &op->list, head: &bo->rx_ops);
1163
1164	/* call can_rx_register() */
1165	do_rx_register = 1;
1166
1167	} /* if ((op = bcm_find_op(&bo->rx_ops, msg_head->can_id, ifindex))) */
1168
1169	/* check flags */
1170
1171	if (op->flags & RX_RTR_FRAME) {
1172	struct canfd_frame *frame0 = op->frames;
1173
1174	/* no timers in RTR-mode */
1175	hrtimer_cancel(timer: &op->thrtimer);
1176	hrtimer_cancel(timer: &op->timer);
1177
1178	/*
1179	* funny feature in RX(!)_SETUP only for RTR-mode:
1180	* copy can_id into frame BUT without RTR-flag to
1181	* prevent a full-load-loopback-test ... ;-]
1182	*/
1183	if ((op->flags & TX_CP_CAN_ID) ||
1184	(frame0->can_id == op->can_id))
1185	frame0->can_id = op->can_id & ~CAN_RTR_FLAG;
1186
1187	} else {
1188	if (op->flags & SETTIMER) {
1189
1190	/* set timer value */
1191	op->ival1 = msg_head->ival1;
1192	op->ival2 = msg_head->ival2;
1193	op->kt_ival1 = bcm_timeval_to_ktime(tv: msg_head->ival1);
1194	op->kt_ival2 = bcm_timeval_to_ktime(tv: msg_head->ival2);
1195
1196	/* disable an active timer due to zero value? */
1197	if (!op->kt_ival1)
1198	hrtimer_cancel(timer: &op->timer);
1199
1200	/*
1201	* In any case cancel the throttle timer, flush
1202	* potentially blocked msgs and reset throttle handling
1203	*/
1204	op->kt_lastmsg = 0;
1205	hrtimer_cancel(timer: &op->thrtimer);
1206	bcm_rx_thr_flush(op);
1207	}
1208
1209	if ((op->flags & STARTTIMER) && op->kt_ival1)
1210	hrtimer_start(timer: &op->timer, tim: op->kt_ival1,
1211	mode: HRTIMER_MODE_REL_SOFT);
1212	}
1213
1214	/* now we can register for can_ids, if we added a new bcm_op */
1215	if (do_rx_register) {
1216	if (ifindex) {
1217	struct net_device *dev;
1218
1219	dev = dev_get_by_index(net: sock_net(sk), ifindex);
1220	if (dev) {
1221	err = can_rx_register(net: sock_net(sk), dev,
1222	can_id: op->can_id,
1223	REGMASK(op->can_id),
1224	func: bcm_rx_handler, data: op,
1225	ident: "bcm", sk);
1226
1227	op->rx_reg_dev = dev;
1228	dev_put(dev);
1229	}
1230
1231	} else
1232	err = can_rx_register(net: sock_net(sk), NULL, can_id: op->can_id,
1233	REGMASK(op->can_id),
1234	func: bcm_rx_handler, data: op, ident: "bcm", sk);
1235	if (err) {
1236	/* this bcm rx op is broken -> remove it */
1237	list_del(entry: &op->list);
1238	bcm_remove_op(op);
1239	return err;
1240	}
1241	}
1242
1243	return msg_head->nframes * op->cfsiz + MHSIZ;
1244	}
1245
1246	/*
1247	* bcm_tx_send - send a single CAN frame to the CAN interface (for bcm_sendmsg)
1248	*/
1249	static int bcm_tx_send(struct msghdr *msg, int ifindex, struct sock *sk,
1250	int cfsiz)
1251	{
1252	struct sk_buff *skb;
1253	struct net_device *dev;
1254	int err;
1255
1256	/* we need a real device to send frames */
1257	if (!ifindex)
1258	return -ENODEV;
1259
1260	skb = alloc_skb(size: cfsiz + sizeof(struct can_skb_priv), GFP_KERNEL);
1261	if (!skb)
1262	return -ENOMEM;
1263
1264	can_skb_reserve(skb);
1265
1266	err = memcpy_from_msg(data: skb_put(skb, len: cfsiz), msg, len: cfsiz);
1267	if (err < 0) {
1268	kfree_skb(skb);
1269	return err;
1270	}
1271
1272	dev = dev_get_by_index(net: sock_net(sk), ifindex);
1273	if (!dev) {
1274	kfree_skb(skb);
1275	return -ENODEV;
1276	}
1277
1278	can_skb_prv(skb)->ifindex = dev->ifindex;
1279	can_skb_prv(skb)->skbcnt = 0;
1280	skb->dev = dev;
1281	can_skb_set_owner(skb, sk);
1282	err = can_send(skb, loop: 1); /* send with loopback */
1283	dev_put(dev);
1284
1285	if (err)
1286	return err;
1287
1288	return cfsiz + MHSIZ;
1289	}
1290
1291	/*
1292	* bcm_sendmsg - process BCM commands (opcodes) from the userspace
1293	*/
1294	static int bcm_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
1295	{
1296	struct sock *sk = sock->sk;
1297	struct bcm_sock *bo = bcm_sk(sk);
1298	int ifindex = bo->ifindex; /* default ifindex for this bcm_op */
1299	struct bcm_msg_head msg_head;
1300	int cfsiz;
1301	int ret; /* read bytes or error codes as return value */
1302
1303	if (!bo->bound)
1304	return -ENOTCONN;
1305
1306	/* check for valid message length from userspace */
1307	if (size < MHSIZ)
1308	return -EINVAL;
1309
1310	/* read message head information */
1311	ret = memcpy_from_msg(data: (u8 *)&msg_head, msg, MHSIZ);
1312	if (ret < 0)
1313	return ret;
1314
1315	cfsiz = CFSIZ(msg_head.flags);
1316	if ((size - MHSIZ) % cfsiz)
1317	return -EINVAL;
1318
1319	/* check for alternative ifindex for this bcm_op */
1320
1321	if (!ifindex && msg->msg_name) {
1322	/* no bound device as default => check msg_name */
1323	DECLARE_SOCKADDR(struct sockaddr_can *, addr, msg->msg_name);
1324
1325	if (msg->msg_namelen < BCM_MIN_NAMELEN)
1326	return -EINVAL;
1327
1328	if (addr->can_family != AF_CAN)
1329	return -EINVAL;
1330
1331	/* ifindex from sendto() */
1332	ifindex = addr->can_ifindex;
1333
1334	if (ifindex) {
1335	struct net_device *dev;
1336
1337	dev = dev_get_by_index(net: sock_net(sk), ifindex);
1338	if (!dev)
1339	return -ENODEV;
1340
1341	if (dev->type != ARPHRD_CAN) {
1342	dev_put(dev);
1343	return -ENODEV;
1344	}
1345
1346	dev_put(dev);
1347	}
1348	}
1349
1350	lock_sock(sk);
1351
1352	switch (msg_head.opcode) {
1353
1354	case TX_SETUP:
1355	ret = bcm_tx_setup(msg_head: &msg_head, msg, ifindex, sk);
1356	break;
1357
1358	case RX_SETUP:
1359	ret = bcm_rx_setup(msg_head: &msg_head, msg, ifindex, sk);
1360	break;
1361
1362	case TX_DELETE:
1363	if (bcm_delete_tx_op(ops: &bo->tx_ops, mh: &msg_head, ifindex))
1364	ret = MHSIZ;
1365	else
1366	ret = -EINVAL;
1367	break;
1368
1369	case RX_DELETE:
1370	if (bcm_delete_rx_op(ops: &bo->rx_ops, mh: &msg_head, ifindex))
1371	ret = MHSIZ;
1372	else
1373	ret = -EINVAL;
1374	break;
1375
1376	case TX_READ:
1377	/* reuse msg_head for the reply to TX_READ */
1378	msg_head.opcode = TX_STATUS;
1379	ret = bcm_read_op(ops: &bo->tx_ops, msg_head: &msg_head, ifindex);
1380	break;
1381
1382	case RX_READ:
1383	/* reuse msg_head for the reply to RX_READ */
1384	msg_head.opcode = RX_STATUS;
1385	ret = bcm_read_op(ops: &bo->rx_ops, msg_head: &msg_head, ifindex);
1386	break;
1387
1388	case TX_SEND:
1389	/* we need exactly one CAN frame behind the msg head */
1390	if ((msg_head.nframes != 1) || (size != cfsiz + MHSIZ))
1391	ret = -EINVAL;
1392	else
1393	ret = bcm_tx_send(msg, ifindex, sk, cfsiz);
1394	break;
1395
1396	default:
1397	ret = -EINVAL;
1398	break;
1399	}
1400
1401	release_sock(sk);
1402
1403	return ret;
1404	}
1405
1406	/*
1407	* notification handler for netdevice status changes
1408	*/
1409	static void bcm_notify(struct bcm_sock *bo, unsigned long msg,
1410	struct net_device *dev)
1411	{
1412	struct sock *sk = &bo->sk;
1413	struct bcm_op *op;
1414	int notify_enodev = 0;
1415
1416	if (!net_eq(net1: dev_net(dev), net2: sock_net(sk)))
1417	return;
1418
1419	switch (msg) {
1420
1421	case NETDEV_UNREGISTER:
1422	lock_sock(sk);
1423
1424	/* remove device specific receive entries */
1425	list_for_each_entry(op, &bo->rx_ops, list)
1426	if (op->rx_reg_dev == dev)
1427	bcm_rx_unreg(dev, op);
1428
1429	/* remove device reference, if this is our bound device */
1430	if (bo->bound && bo->ifindex == dev->ifindex) {
1431	bo->bound = 0;
1432	bo->ifindex = 0;
1433	notify_enodev = 1;
1434	}
1435
1436	release_sock(sk);
1437
1438	if (notify_enodev) {
1439	sk->sk_err = ENODEV;
1440	if (!sock_flag(sk, flag: SOCK_DEAD))
1441	sk_error_report(sk);
1442	}
1443	break;
1444
1445	case NETDEV_DOWN:
1446	if (bo->bound && bo->ifindex == dev->ifindex) {
1447	sk->sk_err = ENETDOWN;
1448	if (!sock_flag(sk, flag: SOCK_DEAD))
1449	sk_error_report(sk);
1450	}
1451	}
1452	}
1453
1454	static int bcm_notifier(struct notifier_block *nb, unsigned long msg,
1455	void *ptr)
1456	{
1457	struct net_device *dev = netdev_notifier_info_to_dev(info: ptr);
1458
1459	if (dev->type != ARPHRD_CAN)
1460	return NOTIFY_DONE;
1461	if (msg != NETDEV_UNREGISTER && msg != NETDEV_DOWN)
1462	return NOTIFY_DONE;
1463	if (unlikely(bcm_busy_notifier)) /* Check for reentrant bug. */
1464	return NOTIFY_DONE;
1465
1466	spin_lock(lock: &bcm_notifier_lock);
1467	list_for_each_entry(bcm_busy_notifier, &bcm_notifier_list, notifier) {
1468	spin_unlock(lock: &bcm_notifier_lock);
1469	bcm_notify(bo: bcm_busy_notifier, msg, dev);
1470	spin_lock(lock: &bcm_notifier_lock);
1471	}
1472	bcm_busy_notifier = NULL;
1473	spin_unlock(lock: &bcm_notifier_lock);
1474	return NOTIFY_DONE;
1475	}
1476
1477	/*
1478	* initial settings for all BCM sockets to be set at socket creation time
1479	*/
1480	static int bcm_init(struct sock *sk)
1481	{
1482	struct bcm_sock *bo = bcm_sk(sk);
1483
1484	bo->bound = 0;
1485	bo->ifindex = 0;
1486	bo->dropped_usr_msgs = 0;
1487	bo->bcm_proc_read = NULL;
1488
1489	INIT_LIST_HEAD(list: &bo->tx_ops);
1490	INIT_LIST_HEAD(list: &bo->rx_ops);
1491
1492	/* set notifier */
1493	spin_lock(lock: &bcm_notifier_lock);
1494	list_add_tail(new: &bo->notifier, head: &bcm_notifier_list);
1495	spin_unlock(lock: &bcm_notifier_lock);
1496
1497	return 0;
1498	}
1499
1500	/*
1501	* standard socket functions
1502	*/
1503	static int bcm_release(struct socket *sock)
1504	{
1505	struct sock *sk = sock->sk;
1506	struct net *net;
1507	struct bcm_sock *bo;
1508	struct bcm_op *op, *next;
1509
1510	if (!sk)
1511	return 0;
1512
1513	net = sock_net(sk);
1514	bo = bcm_sk(sk);
1515
1516	/* remove bcm_ops, timer, rx_unregister(), etc. */
1517
1518	spin_lock(lock: &bcm_notifier_lock);
1519	while (bcm_busy_notifier == bo) {
1520	spin_unlock(lock: &bcm_notifier_lock);
1521	schedule_timeout_uninterruptible(timeout: 1);
1522	spin_lock(lock: &bcm_notifier_lock);
1523	}
1524	list_del(entry: &bo->notifier);
1525	spin_unlock(lock: &bcm_notifier_lock);
1526
1527	lock_sock(sk);
1528
1529	#if IS_ENABLED(CONFIG_PROC_FS)
1530	/* remove procfs entry */
1531	if (net->can.bcmproc_dir && bo->bcm_proc_read)
1532	remove_proc_entry(bo->procname, net->can.bcmproc_dir);
1533	#endif /* CONFIG_PROC_FS */
1534
1535	list_for_each_entry_safe(op, next, &bo->tx_ops, list)
1536	bcm_remove_op(op);
1537
1538	list_for_each_entry_safe(op, next, &bo->rx_ops, list) {
1539	/*
1540	* Don't care if we're bound or not (due to netdev problems)
1541	* can_rx_unregister() is always a save thing to do here.
1542	*/
1543	if (op->ifindex) {
1544	/*
1545	* Only remove subscriptions that had not
1546	* been removed due to NETDEV_UNREGISTER
1547	* in bcm_notifier()
1548	*/
1549	if (op->rx_reg_dev) {
1550	struct net_device *dev;
1551
1552	dev = dev_get_by_index(net, ifindex: op->ifindex);
1553	if (dev) {
1554	bcm_rx_unreg(dev, op);
1555	dev_put(dev);
1556	}
1557	}
1558	} else
1559	can_rx_unregister(net, NULL, can_id: op->can_id,
1560	REGMASK(op->can_id),
1561	func: bcm_rx_handler, data: op);
1562
1563	}
1564
1565	synchronize_rcu();
1566
1567	list_for_each_entry_safe(op, next, &bo->rx_ops, list)
1568	bcm_remove_op(op);
1569
1570	/* remove device reference */
1571	if (bo->bound) {
1572	bo->bound = 0;
1573	bo->ifindex = 0;
1574	}
1575
1576	sock_orphan(sk);
1577	sock->sk = NULL;
1578
1579	release_sock(sk);
1580	sock_put(sk);
1581
1582	return 0;
1583	}
1584
1585	static int bcm_connect(struct socket *sock, struct sockaddr *uaddr, int len,
1586	int flags)
1587	{
1588	struct sockaddr_can *addr = (struct sockaddr_can *)uaddr;
1589	struct sock *sk = sock->sk;
1590	struct bcm_sock *bo = bcm_sk(sk);
1591	struct net *net = sock_net(sk);
1592	int ret = 0;
1593
1594	if (len < BCM_MIN_NAMELEN)
1595	return -EINVAL;
1596
1597	lock_sock(sk);
1598
1599	if (bo->bound) {
1600	ret = -EISCONN;
1601	goto fail;
1602	}
1603
1604	/* bind a device to this socket */
1605	if (addr->can_ifindex) {
1606	struct net_device *dev;
1607
1608	dev = dev_get_by_index(net, ifindex: addr->can_ifindex);
1609	if (!dev) {
1610	ret = -ENODEV;
1611	goto fail;
1612	}
1613	if (dev->type != ARPHRD_CAN) {
1614	dev_put(dev);
1615	ret = -ENODEV;
1616	goto fail;
1617	}
1618
1619	bo->ifindex = dev->ifindex;
1620	dev_put(dev);
1621
1622	} else {
1623	/* no interface reference for ifindex = 0 ('any' CAN device) */
1624	bo->ifindex = 0;
1625	}
1626
1627	#if IS_ENABLED(CONFIG_PROC_FS)
1628	if (net->can.bcmproc_dir) {
1629	/* unique socket address as filename */
1630	sprintf(buf: bo->procname, fmt: "%lu", sock_i_ino(sk));
1631	bo->bcm_proc_read = proc_create_net_single(name: bo->procname, mode: 0644,
1632	parent: net->can.bcmproc_dir,
1633	show: bcm_proc_show, data: sk);
1634	if (!bo->bcm_proc_read) {
1635	ret = -ENOMEM;
1636	goto fail;
1637	}
1638	}
1639	#endif /* CONFIG_PROC_FS */
1640
1641	bo->bound = 1;
1642
1643	fail:
1644	release_sock(sk);
1645
1646	return ret;
1647	}
1648
1649	static int bcm_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
1650	int flags)
1651	{
1652	struct sock *sk = sock->sk;
1653	struct sk_buff *skb;
1654	int error = 0;
1655	int err;
1656
1657	skb = skb_recv_datagram(sk, flags, err: &error);
1658	if (!skb)
1659	return error;
1660
1661	if (skb->len < size)
1662	size = skb->len;
1663
1664	err = memcpy_to_msg(msg, data: skb->data, len: size);
1665	if (err < 0) {
1666	skb_free_datagram(sk, skb);
1667	return err;
1668	}
1669
1670	sock_recv_cmsgs(msg, sk, skb);
1671
1672	if (msg->msg_name) {
1673	__sockaddr_check_size(BCM_MIN_NAMELEN);
1674	msg->msg_namelen = BCM_MIN_NAMELEN;
1675	memcpy(msg->msg_name, skb->cb, msg->msg_namelen);
1676	}
1677
1678	skb_free_datagram(sk, skb);
1679
1680	return size;
1681	}
1682
1683	static int bcm_sock_no_ioctlcmd(struct socket *sock, unsigned int cmd,
1684	unsigned long arg)
1685	{
1686	/* no ioctls for socket layer -> hand it down to NIC layer */
1687	return -ENOIOCTLCMD;
1688	}
1689
1690	static const struct proto_ops bcm_ops = {
1691	.family = PF_CAN,
1692	.release = bcm_release,
1693	.bind = sock_no_bind,
1694	.connect = bcm_connect,
1695	.socketpair = sock_no_socketpair,
1696	.accept = sock_no_accept,
1697	.getname = sock_no_getname,
1698	.poll = datagram_poll,
1699	.ioctl = bcm_sock_no_ioctlcmd,
1700	.gettstamp = sock_gettstamp,
1701	.listen = sock_no_listen,
1702	.shutdown = sock_no_shutdown,
1703	.sendmsg = bcm_sendmsg,
1704	.recvmsg = bcm_recvmsg,
1705	.mmap = sock_no_mmap,
1706	};
1707
1708	static struct proto bcm_proto __read_mostly = {
1709	.name = "CAN_BCM",
1710	.owner = THIS_MODULE,
1711	.obj_size = sizeof(struct bcm_sock),
1712	.init = bcm_init,
1713	};
1714
1715	static const struct can_proto bcm_can_proto = {
1716	.type = SOCK_DGRAM,
1717	.protocol = CAN_BCM,
1718	.ops = &bcm_ops,
1719	.prot = &bcm_proto,
1720	};
1721
1722	static int canbcm_pernet_init(struct net *net)
1723	{
1724	#if IS_ENABLED(CONFIG_PROC_FS)
1725	/* create /proc/net/can-bcm directory */
1726	net->can.bcmproc_dir = proc_net_mkdir(net, name: "can-bcm", parent: net->proc_net);
1727	#endif /* CONFIG_PROC_FS */
1728
1729	return 0;
1730	}
1731
1732	static void canbcm_pernet_exit(struct net *net)
1733	{
1734	#if IS_ENABLED(CONFIG_PROC_FS)
1735	/* remove /proc/net/can-bcm directory */
1736	if (net->can.bcmproc_dir)
1737	remove_proc_entry("can-bcm", net->proc_net);
1738	#endif /* CONFIG_PROC_FS */
1739	}
1740
1741	static struct pernet_operations canbcm_pernet_ops __read_mostly = {
1742	.init = canbcm_pernet_init,
1743	.exit = canbcm_pernet_exit,
1744	};
1745
1746	static struct notifier_block canbcm_notifier = {
1747	.notifier_call = bcm_notifier
1748	};
1749
1750	static int __init bcm_module_init(void)
1751	{
1752	int err;
1753
1754	pr_info("can: broadcast manager protocol\n");
1755
1756	err = register_pernet_subsys(&canbcm_pernet_ops);
1757	if (err)
1758	return err;
1759
1760	err = register_netdevice_notifier(nb: &canbcm_notifier);
1761	if (err)
1762	goto register_notifier_failed;
1763
1764	err = can_proto_register(cp: &bcm_can_proto);
1765	if (err < 0) {
1766	printk(KERN_ERR "can: registration of bcm protocol failed\n");
1767	goto register_proto_failed;
1768	}
1769
1770	return 0;
1771
1772	register_proto_failed:
1773	unregister_netdevice_notifier(nb: &canbcm_notifier);
1774	register_notifier_failed:
1775	unregister_pernet_subsys(&canbcm_pernet_ops);
1776	return err;
1777	}
1778
1779	static void __exit bcm_module_exit(void)
1780	{
1781	can_proto_unregister(cp: &bcm_can_proto);
1782	unregister_netdevice_notifier(nb: &canbcm_notifier);
1783	unregister_pernet_subsys(&canbcm_pernet_ops);
1784	}
1785
1786	module_init(bcm_module_init);
1787	module_exit(bcm_module_exit);
1788