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_LOCAL 0x10 /* frame was created on the local host */
76 #define RX_OWN 0x20 /* frame was sent via the socket it was received on */
77 #define RX_RECV 0x40 /* received data for this element */
78 #define RX_THR 0x80 /* element not been sent due to throttle feature */
79 #define BCM_CAN_FLAGS_MASK 0x0F /* to clean private flags after usage */
80
81 /* get best masking value for can_rx_register() for a given single can_id */
82 #define REGMASK(id) ((id & CAN_EFF_FLAG) ? \
83 (CAN_EFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG) : \
84 (CAN_SFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG))
85
86 MODULE_DESCRIPTION("PF_CAN broadcast manager protocol");
87 MODULE_LICENSE("Dual BSD/GPL");
88 MODULE_AUTHOR("Oliver Hartkopp <oliver.hartkopp@volkswagen.de>");
89 MODULE_ALIAS("can-proto-2");
90
91 #define BCM_MIN_NAMELEN CAN_REQUIRED_SIZE(struct sockaddr_can, can_ifindex)
92
93 /*
94 * easy access to the first 64 bit of can(fd)_frame payload. cp->data is
95 * 64 bit aligned so the offset has to be multiples of 8 which is ensured
96 * by the only callers in bcm_rx_cmp_to_index() bcm_rx_handler().
97 */
get_u64(const struct canfd_frame * cp,int offset)98 static inline u64 get_u64(const struct canfd_frame *cp, int offset)
99 {
100 return *(u64 *)(cp->data + offset);
101 }
102
103 struct bcm_op {
104 struct list_head list;
105 struct rcu_head rcu;
106 int ifindex;
107 canid_t can_id;
108 u32 flags;
109 unsigned long frames_abs, frames_filtered;
110 struct bcm_timeval ival1, ival2;
111 struct hrtimer timer, thrtimer;
112 ktime_t rx_stamp, kt_ival1, kt_ival2, kt_lastmsg;
113 int rx_ifindex;
114 int cfsiz;
115 u32 count;
116 u32 nframes;
117 u32 currframe;
118 /* void pointers to arrays of struct can[fd]_frame */
119 void *frames;
120 void *last_frames;
121 struct canfd_frame sframe;
122 struct canfd_frame last_sframe;
123 struct sock *sk;
124 struct net_device *rx_reg_dev;
125 };
126
127 struct bcm_sock {
128 struct sock sk;
129 int bound;
130 int ifindex;
131 struct list_head notifier;
132 struct list_head rx_ops;
133 struct list_head tx_ops;
134 unsigned long dropped_usr_msgs;
135 struct proc_dir_entry *bcm_proc_read;
136 char procname [32]; /* inode number in decimal with \0 */
137 };
138
139 static LIST_HEAD(bcm_notifier_list);
140 static DEFINE_SPINLOCK(bcm_notifier_lock);
141 static struct bcm_sock *bcm_busy_notifier;
142
143 /* Return pointer to store the extra msg flags for bcm_recvmsg().
144 * We use the space of one unsigned int beyond the 'struct sockaddr_can'
145 * in skb->cb.
146 */
bcm_flags(struct sk_buff * skb)147 static inline unsigned int *bcm_flags(struct sk_buff *skb)
148 {
149 /* return pointer after struct sockaddr_can */
150 return (unsigned int *)(&((struct sockaddr_can *)skb->cb)[1]);
151 }
152
bcm_sk(const struct sock * sk)153 static inline struct bcm_sock *bcm_sk(const struct sock *sk)
154 {
155 return (struct bcm_sock *)sk;
156 }
157
bcm_timeval_to_ktime(struct bcm_timeval tv)158 static inline ktime_t bcm_timeval_to_ktime(struct bcm_timeval tv)
159 {
160 return ktime_set(tv.tv_sec, tv.tv_usec * NSEC_PER_USEC);
161 }
162
163 /* check limitations for timeval provided by user */
bcm_is_invalid_tv(struct bcm_msg_head * msg_head)164 static bool bcm_is_invalid_tv(struct bcm_msg_head *msg_head)
165 {
166 if ((msg_head->ival1.tv_sec < 0) ||
167 (msg_head->ival1.tv_sec > BCM_TIMER_SEC_MAX) ||
168 (msg_head->ival1.tv_usec < 0) ||
169 (msg_head->ival1.tv_usec >= USEC_PER_SEC) ||
170 (msg_head->ival2.tv_sec < 0) ||
171 (msg_head->ival2.tv_sec > BCM_TIMER_SEC_MAX) ||
172 (msg_head->ival2.tv_usec < 0) ||
173 (msg_head->ival2.tv_usec >= USEC_PER_SEC))
174 return true;
175
176 return false;
177 }
178
179 #define CFSIZ(flags) ((flags & CAN_FD_FRAME) ? CANFD_MTU : CAN_MTU)
180 #define OPSIZ sizeof(struct bcm_op)
181 #define MHSIZ sizeof(struct bcm_msg_head)
182
183 /*
184 * procfs functions
185 */
186 #if IS_ENABLED(CONFIG_PROC_FS)
bcm_proc_getifname(struct net * net,char * result,int ifindex)187 static char *bcm_proc_getifname(struct net *net, char *result, int ifindex)
188 {
189 struct net_device *dev;
190
191 if (!ifindex)
192 return "any";
193
194 rcu_read_lock();
195 dev = dev_get_by_index_rcu(net, ifindex);
196 if (dev)
197 strcpy(result, dev->name);
198 else
199 strcpy(result, "???");
200 rcu_read_unlock();
201
202 return result;
203 }
204
bcm_proc_show(struct seq_file * m,void * v)205 static int bcm_proc_show(struct seq_file *m, void *v)
206 {
207 char ifname[IFNAMSIZ];
208 struct net *net = m->private;
209 struct sock *sk = (struct sock *)pde_data(m->file->f_inode);
210 struct bcm_sock *bo = bcm_sk(sk);
211 struct bcm_op *op;
212
213 seq_printf(m, ">>> socket %pK", sk->sk_socket);
214 seq_printf(m, " / sk %pK", sk);
215 seq_printf(m, " / bo %pK", bo);
216 seq_printf(m, " / dropped %lu", bo->dropped_usr_msgs);
217 seq_printf(m, " / bound %s", bcm_proc_getifname(net, ifname, bo->ifindex));
218 seq_printf(m, " <<<\n");
219
220 list_for_each_entry(op, &bo->rx_ops, list) {
221
222 unsigned long reduction;
223
224 /* print only active entries & prevent division by zero */
225 if (!op->frames_abs)
226 continue;
227
228 seq_printf(m, "rx_op: %03X %-5s ", op->can_id,
229 bcm_proc_getifname(net, ifname, op->ifindex));
230
231 if (op->flags & CAN_FD_FRAME)
232 seq_printf(m, "(%u)", op->nframes);
233 else
234 seq_printf(m, "[%u]", op->nframes);
235
236 seq_printf(m, "%c ", (op->flags & RX_CHECK_DLC) ? 'd' : ' ');
237
238 if (op->kt_ival1)
239 seq_printf(m, "timeo=%lld ",
240 (long long)ktime_to_us(op->kt_ival1));
241
242 if (op->kt_ival2)
243 seq_printf(m, "thr=%lld ",
244 (long long)ktime_to_us(op->kt_ival2));
245
246 seq_printf(m, "# recv %ld (%ld) => reduction: ",
247 op->frames_filtered, op->frames_abs);
248
249 reduction = 100 - (op->frames_filtered * 100) / op->frames_abs;
250
251 seq_printf(m, "%s%ld%%\n",
252 (reduction == 100) ? "near " : "", reduction);
253 }
254
255 list_for_each_entry(op, &bo->tx_ops, list) {
256
257 seq_printf(m, "tx_op: %03X %s ", op->can_id,
258 bcm_proc_getifname(net, ifname, op->ifindex));
259
260 if (op->flags & CAN_FD_FRAME)
261 seq_printf(m, "(%u) ", op->nframes);
262 else
263 seq_printf(m, "[%u] ", op->nframes);
264
265 if (op->kt_ival1)
266 seq_printf(m, "t1=%lld ",
267 (long long)ktime_to_us(op->kt_ival1));
268
269 if (op->kt_ival2)
270 seq_printf(m, "t2=%lld ",
271 (long long)ktime_to_us(op->kt_ival2));
272
273 seq_printf(m, "# sent %ld\n", op->frames_abs);
274 }
275 seq_putc(m, '\n');
276 return 0;
277 }
278 #endif /* CONFIG_PROC_FS */
279
280 /*
281 * bcm_can_tx - send the (next) CAN frame to the appropriate CAN interface
282 * of the given bcm tx op
283 */
bcm_can_tx(struct bcm_op * op)284 static void bcm_can_tx(struct bcm_op *op)
285 {
286 struct sk_buff *skb;
287 struct net_device *dev;
288 struct canfd_frame *cf = op->frames + op->cfsiz * op->currframe;
289 int err;
290
291 /* no target device? => exit */
292 if (!op->ifindex)
293 return;
294
295 dev = dev_get_by_index(sock_net(op->sk), op->ifindex);
296 if (!dev) {
297 /* RFC: should this bcm_op remove itself here? */
298 return;
299 }
300
301 skb = alloc_skb(op->cfsiz + sizeof(struct can_skb_priv), gfp_any());
302 if (!skb)
303 goto out;
304
305 can_skb_reserve(skb);
306 can_skb_prv(skb)->ifindex = dev->ifindex;
307 can_skb_prv(skb)->skbcnt = 0;
308
309 skb_put_data(skb, cf, op->cfsiz);
310
311 /* send with loopback */
312 skb->dev = dev;
313 can_skb_set_owner(skb, op->sk);
314 err = can_send(skb, 1);
315 if (!err)
316 op->frames_abs++;
317
318 op->currframe++;
319
320 /* reached last frame? */
321 if (op->currframe >= op->nframes)
322 op->currframe = 0;
323 out:
324 dev_put(dev);
325 }
326
327 /*
328 * bcm_send_to_user - send a BCM message to the userspace
329 * (consisting of bcm_msg_head + x CAN frames)
330 */
bcm_send_to_user(struct bcm_op * op,struct bcm_msg_head * head,struct canfd_frame * frames,int has_timestamp)331 static void bcm_send_to_user(struct bcm_op *op, struct bcm_msg_head *head,
332 struct canfd_frame *frames, int has_timestamp)
333 {
334 struct sk_buff *skb;
335 struct canfd_frame *firstframe;
336 struct sockaddr_can *addr;
337 struct sock *sk = op->sk;
338 unsigned int datalen = head->nframes * op->cfsiz;
339 int err;
340 unsigned int *pflags;
341
342 skb = alloc_skb(sizeof(*head) + datalen, gfp_any());
343 if (!skb)
344 return;
345
346 skb_put_data(skb, head, sizeof(*head));
347
348 /* ensure space for sockaddr_can and msg flags */
349 sock_skb_cb_check_size(sizeof(struct sockaddr_can) +
350 sizeof(unsigned int));
351
352 /* initialize msg flags */
353 pflags = bcm_flags(skb);
354 *pflags = 0;
355
356 if (head->nframes) {
357 /* CAN frames starting here */
358 firstframe = (struct canfd_frame *)skb_tail_pointer(skb);
359
360 skb_put_data(skb, frames, datalen);
361
362 /*
363 * the BCM uses the flags-element of the canfd_frame
364 * structure for internal purposes. This is only
365 * relevant for updates that are generated by the
366 * BCM, where nframes is 1
367 */
368 if (head->nframes == 1) {
369 if (firstframe->flags & RX_LOCAL)
370 *pflags |= MSG_DONTROUTE;
371 if (firstframe->flags & RX_OWN)
372 *pflags |= MSG_CONFIRM;
373
374 firstframe->flags &= BCM_CAN_FLAGS_MASK;
375 }
376 }
377
378 if (has_timestamp) {
379 /* restore rx timestamp */
380 skb->tstamp = op->rx_stamp;
381 }
382
383 /*
384 * Put the datagram to the queue so that bcm_recvmsg() can
385 * get it from there. We need to pass the interface index to
386 * bcm_recvmsg(). We pass a whole struct sockaddr_can in skb->cb
387 * containing the interface index.
388 */
389
390 addr = (struct sockaddr_can *)skb->cb;
391 memset(addr, 0, sizeof(*addr));
392 addr->can_family = AF_CAN;
393 addr->can_ifindex = op->rx_ifindex;
394
395 err = sock_queue_rcv_skb(sk, skb);
396 if (err < 0) {
397 struct bcm_sock *bo = bcm_sk(sk);
398
399 kfree_skb(skb);
400 /* don't care about overflows in this statistic */
401 bo->dropped_usr_msgs++;
402 }
403 }
404
bcm_tx_set_expiry(struct bcm_op * op,struct hrtimer * hrt)405 static bool bcm_tx_set_expiry(struct bcm_op *op, struct hrtimer *hrt)
406 {
407 ktime_t ival;
408
409 if (op->kt_ival1 && op->count)
410 ival = op->kt_ival1;
411 else if (op->kt_ival2)
412 ival = op->kt_ival2;
413 else
414 return false;
415
416 hrtimer_set_expires(hrt, ktime_add(ktime_get(), ival));
417 return true;
418 }
419
bcm_tx_start_timer(struct bcm_op * op)420 static void bcm_tx_start_timer(struct bcm_op *op)
421 {
422 if (bcm_tx_set_expiry(op, &op->timer))
423 hrtimer_start_expires(&op->timer, HRTIMER_MODE_ABS_SOFT);
424 }
425
426 /* bcm_tx_timeout_handler - performs cyclic CAN frame transmissions */
bcm_tx_timeout_handler(struct hrtimer * hrtimer)427 static enum hrtimer_restart bcm_tx_timeout_handler(struct hrtimer *hrtimer)
428 {
429 struct bcm_op *op = container_of(hrtimer, struct bcm_op, timer);
430 struct bcm_msg_head msg_head;
431
432 if (op->kt_ival1 && (op->count > 0)) {
433 op->count--;
434 if (!op->count && (op->flags & TX_COUNTEVT)) {
435
436 /* create notification to user */
437 memset(&msg_head, 0, sizeof(msg_head));
438 msg_head.opcode = TX_EXPIRED;
439 msg_head.flags = op->flags;
440 msg_head.count = op->count;
441 msg_head.ival1 = op->ival1;
442 msg_head.ival2 = op->ival2;
443 msg_head.can_id = op->can_id;
444 msg_head.nframes = 0;
445
446 bcm_send_to_user(op, &msg_head, NULL, 0);
447 }
448 bcm_can_tx(op);
449
450 } else if (op->kt_ival2) {
451 bcm_can_tx(op);
452 }
453
454 return bcm_tx_set_expiry(op, &op->timer) ?
455 HRTIMER_RESTART : HRTIMER_NORESTART;
456 }
457
458 /*
459 * bcm_rx_changed - create a RX_CHANGED notification due to changed content
460 */
bcm_rx_changed(struct bcm_op * op,struct canfd_frame * data)461 static void bcm_rx_changed(struct bcm_op *op, struct canfd_frame *data)
462 {
463 struct bcm_msg_head head;
464
465 /* update statistics */
466 op->frames_filtered++;
467
468 /* prevent statistics overflow */
469 if (op->frames_filtered > ULONG_MAX/100)
470 op->frames_filtered = op->frames_abs = 0;
471
472 /* this element is not throttled anymore */
473 data->flags &= ~RX_THR;
474
475 memset(&head, 0, sizeof(head));
476 head.opcode = RX_CHANGED;
477 head.flags = op->flags;
478 head.count = op->count;
479 head.ival1 = op->ival1;
480 head.ival2 = op->ival2;
481 head.can_id = op->can_id;
482 head.nframes = 1;
483
484 bcm_send_to_user(op, &head, data, 1);
485 }
486
487 /*
488 * bcm_rx_update_and_send - process a detected relevant receive content change
489 * 1. update the last received data
490 * 2. send a notification to the user (if possible)
491 */
bcm_rx_update_and_send(struct bcm_op * op,struct canfd_frame * lastdata,const struct canfd_frame * rxdata,unsigned char traffic_flags)492 static void bcm_rx_update_and_send(struct bcm_op *op,
493 struct canfd_frame *lastdata,
494 const struct canfd_frame *rxdata,
495 unsigned char traffic_flags)
496 {
497 memcpy(lastdata, rxdata, op->cfsiz);
498
499 /* mark as used and throttled by default */
500 lastdata->flags |= (RX_RECV|RX_THR);
501
502 /* add own/local/remote traffic flags */
503 lastdata->flags |= traffic_flags;
504
505 /* throttling mode inactive ? */
506 if (!op->kt_ival2) {
507 /* send RX_CHANGED to the user immediately */
508 bcm_rx_changed(op, lastdata);
509 return;
510 }
511
512 /* with active throttling timer we are just done here */
513 if (hrtimer_active(&op->thrtimer))
514 return;
515
516 /* first reception with enabled throttling mode */
517 if (!op->kt_lastmsg)
518 goto rx_changed_settime;
519
520 /* got a second frame inside a potential throttle period? */
521 if (ktime_us_delta(ktime_get(), op->kt_lastmsg) <
522 ktime_to_us(op->kt_ival2)) {
523 /* do not send the saved data - only start throttle timer */
524 hrtimer_start(&op->thrtimer,
525 ktime_add(op->kt_lastmsg, op->kt_ival2),
526 HRTIMER_MODE_ABS_SOFT);
527 return;
528 }
529
530 /* the gap was that big, that throttling was not needed here */
531 rx_changed_settime:
532 bcm_rx_changed(op, lastdata);
533 op->kt_lastmsg = ktime_get();
534 }
535
536 /*
537 * bcm_rx_cmp_to_index - (bit)compares the currently received data to formerly
538 * received data stored in op->last_frames[]
539 */
bcm_rx_cmp_to_index(struct bcm_op * op,unsigned int index,const struct canfd_frame * rxdata,unsigned char traffic_flags)540 static void bcm_rx_cmp_to_index(struct bcm_op *op, unsigned int index,
541 const struct canfd_frame *rxdata,
542 unsigned char traffic_flags)
543 {
544 struct canfd_frame *cf = op->frames + op->cfsiz * index;
545 struct canfd_frame *lcf = op->last_frames + op->cfsiz * index;
546 int i;
547
548 /*
549 * no one uses the MSBs of flags for comparison,
550 * so we use it here to detect the first time of reception
551 */
552
553 if (!(lcf->flags & RX_RECV)) {
554 /* received data for the first time => send update to user */
555 bcm_rx_update_and_send(op, lcf, rxdata, traffic_flags);
556 return;
557 }
558
559 /* do a real check in CAN frame data section */
560 for (i = 0; i < rxdata->len; i += 8) {
561 if ((get_u64(cf, i) & get_u64(rxdata, i)) !=
562 (get_u64(cf, i) & get_u64(lcf, i))) {
563 bcm_rx_update_and_send(op, lcf, rxdata, traffic_flags);
564 return;
565 }
566 }
567
568 if (op->flags & RX_CHECK_DLC) {
569 /* do a real check in CAN frame length */
570 if (rxdata->len != lcf->len) {
571 bcm_rx_update_and_send(op, lcf, rxdata, traffic_flags);
572 return;
573 }
574 }
575 }
576
577 /*
578 * bcm_rx_starttimer - enable timeout monitoring for CAN frame reception
579 */
bcm_rx_starttimer(struct bcm_op * op)580 static void bcm_rx_starttimer(struct bcm_op *op)
581 {
582 if (op->flags & RX_NO_AUTOTIMER)
583 return;
584
585 if (op->kt_ival1)
586 hrtimer_start(&op->timer, op->kt_ival1, HRTIMER_MODE_REL_SOFT);
587 }
588
589 /* bcm_rx_timeout_handler - when the (cyclic) CAN frame reception timed out */
bcm_rx_timeout_handler(struct hrtimer * hrtimer)590 static enum hrtimer_restart bcm_rx_timeout_handler(struct hrtimer *hrtimer)
591 {
592 struct bcm_op *op = container_of(hrtimer, struct bcm_op, timer);
593 struct bcm_msg_head msg_head;
594
595 /* if user wants to be informed, when cyclic CAN-Messages come back */
596 if ((op->flags & RX_ANNOUNCE_RESUME) && op->last_frames) {
597 /* clear received CAN frames to indicate 'nothing received' */
598 memset(op->last_frames, 0, op->nframes * op->cfsiz);
599 }
600
601 /* create notification to user */
602 memset(&msg_head, 0, sizeof(msg_head));
603 msg_head.opcode = RX_TIMEOUT;
604 msg_head.flags = op->flags;
605 msg_head.count = op->count;
606 msg_head.ival1 = op->ival1;
607 msg_head.ival2 = op->ival2;
608 msg_head.can_id = op->can_id;
609 msg_head.nframes = 0;
610
611 bcm_send_to_user(op, &msg_head, NULL, 0);
612
613 return HRTIMER_NORESTART;
614 }
615
616 /*
617 * bcm_rx_do_flush - helper for bcm_rx_thr_flush
618 */
bcm_rx_do_flush(struct bcm_op * op,unsigned int index)619 static inline int bcm_rx_do_flush(struct bcm_op *op, unsigned int index)
620 {
621 struct canfd_frame *lcf = op->last_frames + op->cfsiz * index;
622
623 if ((op->last_frames) && (lcf->flags & RX_THR)) {
624 bcm_rx_changed(op, lcf);
625 return 1;
626 }
627 return 0;
628 }
629
630 /*
631 * bcm_rx_thr_flush - Check for throttled data and send it to the userspace
632 */
bcm_rx_thr_flush(struct bcm_op * op)633 static int bcm_rx_thr_flush(struct bcm_op *op)
634 {
635 int updated = 0;
636
637 if (op->nframes > 1) {
638 unsigned int i;
639
640 /* for MUX filter we start at index 1 */
641 for (i = 1; i < op->nframes; i++)
642 updated += bcm_rx_do_flush(op, i);
643
644 } else {
645 /* for RX_FILTER_ID and simple filter */
646 updated += bcm_rx_do_flush(op, 0);
647 }
648
649 return updated;
650 }
651
652 /*
653 * bcm_rx_thr_handler - the time for blocked content updates is over now:
654 * Check for throttled data and send it to the userspace
655 */
bcm_rx_thr_handler(struct hrtimer * hrtimer)656 static enum hrtimer_restart bcm_rx_thr_handler(struct hrtimer *hrtimer)
657 {
658 struct bcm_op *op = container_of(hrtimer, struct bcm_op, thrtimer);
659
660 if (bcm_rx_thr_flush(op)) {
661 hrtimer_forward_now(hrtimer, op->kt_ival2);
662 return HRTIMER_RESTART;
663 } else {
664 /* rearm throttle handling */
665 op->kt_lastmsg = 0;
666 return HRTIMER_NORESTART;
667 }
668 }
669
670 /*
671 * bcm_rx_handler - handle a CAN frame reception
672 */
bcm_rx_handler(struct sk_buff * skb,void * data)673 static void bcm_rx_handler(struct sk_buff *skb, void *data)
674 {
675 struct bcm_op *op = (struct bcm_op *)data;
676 const struct canfd_frame *rxframe = (struct canfd_frame *)skb->data;
677 unsigned int i;
678 unsigned char traffic_flags;
679
680 if (op->can_id != rxframe->can_id)
681 return;
682
683 /* make sure to handle the correct frame type (CAN / CAN FD) */
684 if (op->flags & CAN_FD_FRAME) {
685 if (!can_is_canfd_skb(skb))
686 return;
687 } else {
688 if (!can_is_can_skb(skb))
689 return;
690 }
691
692 /* disable timeout */
693 hrtimer_cancel(&op->timer);
694
695 /* save rx timestamp */
696 op->rx_stamp = skb->tstamp;
697 /* save originator for recvfrom() */
698 op->rx_ifindex = skb->dev->ifindex;
699 /* update statistics */
700 op->frames_abs++;
701
702 if (op->flags & RX_RTR_FRAME) {
703 /* send reply for RTR-request (placed in op->frames[0]) */
704 bcm_can_tx(op);
705 return;
706 }
707
708 /* compute flags to distinguish between own/local/remote CAN traffic */
709 traffic_flags = 0;
710 if (skb->sk) {
711 traffic_flags |= RX_LOCAL;
712 if (skb->sk == op->sk)
713 traffic_flags |= RX_OWN;
714 }
715
716 if (op->flags & RX_FILTER_ID) {
717 /* the easiest case */
718 bcm_rx_update_and_send(op, op->last_frames, rxframe,
719 traffic_flags);
720 goto rx_starttimer;
721 }
722
723 if (op->nframes == 1) {
724 /* simple compare with index 0 */
725 bcm_rx_cmp_to_index(op, 0, rxframe, traffic_flags);
726 goto rx_starttimer;
727 }
728
729 if (op->nframes > 1) {
730 /*
731 * multiplex compare
732 *
733 * find the first multiplex mask that fits.
734 * Remark: The MUX-mask is stored in index 0 - but only the
735 * first 64 bits of the frame data[] are relevant (CAN FD)
736 */
737
738 for (i = 1; i < op->nframes; i++) {
739 if ((get_u64(op->frames, 0) & get_u64(rxframe, 0)) ==
740 (get_u64(op->frames, 0) &
741 get_u64(op->frames + op->cfsiz * i, 0))) {
742 bcm_rx_cmp_to_index(op, i, rxframe,
743 traffic_flags);
744 break;
745 }
746 }
747 }
748
749 rx_starttimer:
750 bcm_rx_starttimer(op);
751 }
752
753 /*
754 * helpers for bcm_op handling: find & delete bcm [rx|tx] op elements
755 */
bcm_find_op(struct list_head * ops,struct bcm_msg_head * mh,int ifindex)756 static struct bcm_op *bcm_find_op(struct list_head *ops,
757 struct bcm_msg_head *mh, int ifindex)
758 {
759 struct bcm_op *op;
760
761 list_for_each_entry(op, ops, list) {
762 if ((op->can_id == mh->can_id) && (op->ifindex == ifindex) &&
763 (op->flags & CAN_FD_FRAME) == (mh->flags & CAN_FD_FRAME))
764 return op;
765 }
766
767 return NULL;
768 }
769
bcm_free_op_rcu(struct rcu_head * rcu_head)770 static void bcm_free_op_rcu(struct rcu_head *rcu_head)
771 {
772 struct bcm_op *op = container_of(rcu_head, struct bcm_op, rcu);
773
774 if ((op->frames) && (op->frames != &op->sframe))
775 kfree(op->frames);
776
777 if ((op->last_frames) && (op->last_frames != &op->last_sframe))
778 kfree(op->last_frames);
779
780 kfree(op);
781 }
782
bcm_remove_op(struct bcm_op * op)783 static void bcm_remove_op(struct bcm_op *op)
784 {
785 hrtimer_cancel(&op->timer);
786 hrtimer_cancel(&op->thrtimer);
787
788 call_rcu(&op->rcu, bcm_free_op_rcu);
789 }
790
bcm_rx_unreg(struct net_device * dev,struct bcm_op * op)791 static void bcm_rx_unreg(struct net_device *dev, struct bcm_op *op)
792 {
793 if (op->rx_reg_dev == dev) {
794 can_rx_unregister(dev_net(dev), dev, op->can_id,
795 REGMASK(op->can_id), bcm_rx_handler, op);
796
797 /* mark as removed subscription */
798 op->rx_reg_dev = NULL;
799 } else
800 printk(KERN_ERR "can-bcm: bcm_rx_unreg: registered device "
801 "mismatch %p %p\n", op->rx_reg_dev, dev);
802 }
803
804 /*
805 * bcm_delete_rx_op - find and remove a rx op (returns number of removed ops)
806 */
bcm_delete_rx_op(struct list_head * ops,struct bcm_msg_head * mh,int ifindex)807 static int bcm_delete_rx_op(struct list_head *ops, struct bcm_msg_head *mh,
808 int ifindex)
809 {
810 struct bcm_op *op, *n;
811
812 list_for_each_entry_safe(op, n, ops, list) {
813 if ((op->can_id == mh->can_id) && (op->ifindex == ifindex) &&
814 (op->flags & CAN_FD_FRAME) == (mh->flags & CAN_FD_FRAME)) {
815
816 /* disable automatic timer on frame reception */
817 op->flags |= RX_NO_AUTOTIMER;
818
819 /*
820 * Don't care if we're bound or not (due to netdev
821 * problems) can_rx_unregister() is always a save
822 * thing to do here.
823 */
824 if (op->ifindex) {
825 /*
826 * Only remove subscriptions that had not
827 * been removed due to NETDEV_UNREGISTER
828 * in bcm_notifier()
829 */
830 if (op->rx_reg_dev) {
831 struct net_device *dev;
832
833 dev = dev_get_by_index(sock_net(op->sk),
834 op->ifindex);
835 if (dev) {
836 bcm_rx_unreg(dev, op);
837 dev_put(dev);
838 }
839 }
840 } else
841 can_rx_unregister(sock_net(op->sk), NULL,
842 op->can_id,
843 REGMASK(op->can_id),
844 bcm_rx_handler, op);
845
846 list_del(&op->list);
847 bcm_remove_op(op);
848 return 1; /* done */
849 }
850 }
851
852 return 0; /* not found */
853 }
854
855 /*
856 * bcm_delete_tx_op - find and remove a tx op (returns number of removed ops)
857 */
bcm_delete_tx_op(struct list_head * ops,struct bcm_msg_head * mh,int ifindex)858 static int bcm_delete_tx_op(struct list_head *ops, struct bcm_msg_head *mh,
859 int ifindex)
860 {
861 struct bcm_op *op, *n;
862
863 list_for_each_entry_safe(op, n, ops, list) {
864 if ((op->can_id == mh->can_id) && (op->ifindex == ifindex) &&
865 (op->flags & CAN_FD_FRAME) == (mh->flags & CAN_FD_FRAME)) {
866 list_del(&op->list);
867 bcm_remove_op(op);
868 return 1; /* done */
869 }
870 }
871
872 return 0; /* not found */
873 }
874
875 /*
876 * bcm_read_op - read out a bcm_op and send it to the user (for bcm_sendmsg)
877 */
bcm_read_op(struct list_head * ops,struct bcm_msg_head * msg_head,int ifindex)878 static int bcm_read_op(struct list_head *ops, struct bcm_msg_head *msg_head,
879 int ifindex)
880 {
881 struct bcm_op *op = bcm_find_op(ops, msg_head, ifindex);
882
883 if (!op)
884 return -EINVAL;
885
886 /* put current values into msg_head */
887 msg_head->flags = op->flags;
888 msg_head->count = op->count;
889 msg_head->ival1 = op->ival1;
890 msg_head->ival2 = op->ival2;
891 msg_head->nframes = op->nframes;
892
893 bcm_send_to_user(op, msg_head, op->frames, 0);
894
895 return MHSIZ;
896 }
897
898 /*
899 * bcm_tx_setup - create or update a bcm tx op (for bcm_sendmsg)
900 */
bcm_tx_setup(struct bcm_msg_head * msg_head,struct msghdr * msg,int ifindex,struct sock * sk)901 static int bcm_tx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
902 int ifindex, struct sock *sk)
903 {
904 struct bcm_sock *bo = bcm_sk(sk);
905 struct bcm_op *op;
906 struct canfd_frame *cf;
907 unsigned int i;
908 int err;
909
910 /* we need a real device to send frames */
911 if (!ifindex)
912 return -ENODEV;
913
914 /* check nframes boundaries - we need at least one CAN frame */
915 if (msg_head->nframes < 1 || msg_head->nframes > MAX_NFRAMES)
916 return -EINVAL;
917
918 /* check timeval limitations */
919 if ((msg_head->flags & SETTIMER) && bcm_is_invalid_tv(msg_head))
920 return -EINVAL;
921
922 /* check the given can_id */
923 op = bcm_find_op(&bo->tx_ops, msg_head, ifindex);
924 if (op) {
925 /* update existing BCM operation */
926
927 /*
928 * Do we need more space for the CAN frames than currently
929 * allocated? -> This is a _really_ unusual use-case and
930 * therefore (complexity / locking) it is not supported.
931 */
932 if (msg_head->nframes > op->nframes)
933 return -E2BIG;
934
935 /* update CAN frames content */
936 for (i = 0; i < msg_head->nframes; i++) {
937
938 cf = op->frames + op->cfsiz * i;
939 err = memcpy_from_msg((u8 *)cf, msg, op->cfsiz);
940
941 if (op->flags & CAN_FD_FRAME) {
942 if (cf->len > 64)
943 err = -EINVAL;
944 } else {
945 if (cf->len > 8)
946 err = -EINVAL;
947 }
948
949 if (err < 0)
950 return err;
951
952 if (msg_head->flags & TX_CP_CAN_ID) {
953 /* copy can_id into frame */
954 cf->can_id = msg_head->can_id;
955 }
956 }
957 op->flags = msg_head->flags;
958
959 } else {
960 /* insert new BCM operation for the given can_id */
961
962 op = kzalloc(OPSIZ, GFP_KERNEL);
963 if (!op)
964 return -ENOMEM;
965
966 op->can_id = msg_head->can_id;
967 op->cfsiz = CFSIZ(msg_head->flags);
968 op->flags = msg_head->flags;
969
970 /* create array for CAN frames and copy the data */
971 if (msg_head->nframes > 1) {
972 op->frames = kmalloc_array(msg_head->nframes,
973 op->cfsiz,
974 GFP_KERNEL);
975 if (!op->frames) {
976 kfree(op);
977 return -ENOMEM;
978 }
979 } else
980 op->frames = &op->sframe;
981
982 for (i = 0; i < msg_head->nframes; i++) {
983
984 cf = op->frames + op->cfsiz * i;
985 err = memcpy_from_msg((u8 *)cf, msg, op->cfsiz);
986 if (err < 0)
987 goto free_op;
988
989 if (op->flags & CAN_FD_FRAME) {
990 if (cf->len > 64)
991 err = -EINVAL;
992 } else {
993 if (cf->len > 8)
994 err = -EINVAL;
995 }
996
997 if (err < 0)
998 goto free_op;
999
1000 if (msg_head->flags & TX_CP_CAN_ID) {
1001 /* copy can_id into frame */
1002 cf->can_id = msg_head->can_id;
1003 }
1004 }
1005
1006 /* tx_ops never compare with previous received messages */
1007 op->last_frames = NULL;
1008
1009 /* bcm_can_tx / bcm_tx_timeout_handler needs this */
1010 op->sk = sk;
1011 op->ifindex = ifindex;
1012
1013 /* initialize uninitialized (kzalloc) structure */
1014 hrtimer_setup(&op->timer, bcm_tx_timeout_handler, CLOCK_MONOTONIC,
1015 HRTIMER_MODE_REL_SOFT);
1016
1017 /* currently unused in tx_ops */
1018 hrtimer_setup(&op->thrtimer, hrtimer_dummy_timeout, CLOCK_MONOTONIC,
1019 HRTIMER_MODE_REL_SOFT);
1020
1021 /* add this bcm_op to the list of the tx_ops */
1022 list_add(&op->list, &bo->tx_ops);
1023
1024 } /* if ((op = bcm_find_op(&bo->tx_ops, msg_head->can_id, ifindex))) */
1025
1026 if (op->nframes != msg_head->nframes) {
1027 op->nframes = msg_head->nframes;
1028 /* start multiple frame transmission with index 0 */
1029 op->currframe = 0;
1030 }
1031
1032 /* check flags */
1033
1034 if (op->flags & TX_RESET_MULTI_IDX) {
1035 /* start multiple frame transmission with index 0 */
1036 op->currframe = 0;
1037 }
1038
1039 if (op->flags & SETTIMER) {
1040 /* set timer values */
1041 op->count = msg_head->count;
1042 op->ival1 = msg_head->ival1;
1043 op->ival2 = msg_head->ival2;
1044 op->kt_ival1 = bcm_timeval_to_ktime(msg_head->ival1);
1045 op->kt_ival2 = bcm_timeval_to_ktime(msg_head->ival2);
1046
1047 /* disable an active timer due to zero values? */
1048 if (!op->kt_ival1 && !op->kt_ival2)
1049 hrtimer_cancel(&op->timer);
1050 }
1051
1052 if (op->flags & STARTTIMER) {
1053 hrtimer_cancel(&op->timer);
1054 /* spec: send CAN frame when starting timer */
1055 op->flags |= TX_ANNOUNCE;
1056 }
1057
1058 if (op->flags & TX_ANNOUNCE) {
1059 bcm_can_tx(op);
1060 if (op->count)
1061 op->count--;
1062 }
1063
1064 if (op->flags & STARTTIMER)
1065 bcm_tx_start_timer(op);
1066
1067 return msg_head->nframes * op->cfsiz + MHSIZ;
1068
1069 free_op:
1070 if (op->frames != &op->sframe)
1071 kfree(op->frames);
1072 kfree(op);
1073 return err;
1074 }
1075
1076 /*
1077 * bcm_rx_setup - create or update a bcm rx op (for bcm_sendmsg)
1078 */
bcm_rx_setup(struct bcm_msg_head * msg_head,struct msghdr * msg,int ifindex,struct sock * sk)1079 static int bcm_rx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
1080 int ifindex, struct sock *sk)
1081 {
1082 struct bcm_sock *bo = bcm_sk(sk);
1083 struct bcm_op *op;
1084 int do_rx_register;
1085 int err = 0;
1086
1087 if ((msg_head->flags & RX_FILTER_ID) || (!(msg_head->nframes))) {
1088 /* be robust against wrong usage ... */
1089 msg_head->flags |= RX_FILTER_ID;
1090 /* ignore trailing garbage */
1091 msg_head->nframes = 0;
1092 }
1093
1094 /* the first element contains the mux-mask => MAX_NFRAMES + 1 */
1095 if (msg_head->nframes > MAX_NFRAMES + 1)
1096 return -EINVAL;
1097
1098 if ((msg_head->flags & RX_RTR_FRAME) &&
1099 ((msg_head->nframes != 1) ||
1100 (!(msg_head->can_id & CAN_RTR_FLAG))))
1101 return -EINVAL;
1102
1103 /* check timeval limitations */
1104 if ((msg_head->flags & SETTIMER) && bcm_is_invalid_tv(msg_head))
1105 return -EINVAL;
1106
1107 /* check the given can_id */
1108 op = bcm_find_op(&bo->rx_ops, msg_head, ifindex);
1109 if (op) {
1110 /* update existing BCM operation */
1111
1112 /*
1113 * Do we need more space for the CAN frames than currently
1114 * allocated? -> This is a _really_ unusual use-case and
1115 * therefore (complexity / locking) it is not supported.
1116 */
1117 if (msg_head->nframes > op->nframes)
1118 return -E2BIG;
1119
1120 if (msg_head->nframes) {
1121 /* update CAN frames content */
1122 err = memcpy_from_msg(op->frames, msg,
1123 msg_head->nframes * op->cfsiz);
1124 if (err < 0)
1125 return err;
1126
1127 /* clear last_frames to indicate 'nothing received' */
1128 memset(op->last_frames, 0, msg_head->nframes * op->cfsiz);
1129 }
1130
1131 op->nframes = msg_head->nframes;
1132 op->flags = msg_head->flags;
1133
1134 /* Only an update -> do not call can_rx_register() */
1135 do_rx_register = 0;
1136
1137 } else {
1138 /* insert new BCM operation for the given can_id */
1139 op = kzalloc(OPSIZ, GFP_KERNEL);
1140 if (!op)
1141 return -ENOMEM;
1142
1143 op->can_id = msg_head->can_id;
1144 op->nframes = msg_head->nframes;
1145 op->cfsiz = CFSIZ(msg_head->flags);
1146 op->flags = msg_head->flags;
1147
1148 if (msg_head->nframes > 1) {
1149 /* create array for CAN frames and copy the data */
1150 op->frames = kmalloc_array(msg_head->nframes,
1151 op->cfsiz,
1152 GFP_KERNEL);
1153 if (!op->frames) {
1154 kfree(op);
1155 return -ENOMEM;
1156 }
1157
1158 /* create and init array for received CAN frames */
1159 op->last_frames = kcalloc(msg_head->nframes,
1160 op->cfsiz,
1161 GFP_KERNEL);
1162 if (!op->last_frames) {
1163 kfree(op->frames);
1164 kfree(op);
1165 return -ENOMEM;
1166 }
1167
1168 } else {
1169 op->frames = &op->sframe;
1170 op->last_frames = &op->last_sframe;
1171 }
1172
1173 if (msg_head->nframes) {
1174 err = memcpy_from_msg(op->frames, msg,
1175 msg_head->nframes * op->cfsiz);
1176 if (err < 0) {
1177 if (op->frames != &op->sframe)
1178 kfree(op->frames);
1179 if (op->last_frames != &op->last_sframe)
1180 kfree(op->last_frames);
1181 kfree(op);
1182 return err;
1183 }
1184 }
1185
1186 /* bcm_can_tx / bcm_tx_timeout_handler needs this */
1187 op->sk = sk;
1188 op->ifindex = ifindex;
1189
1190 /* ifindex for timeout events w/o previous frame reception */
1191 op->rx_ifindex = ifindex;
1192
1193 /* initialize uninitialized (kzalloc) structure */
1194 hrtimer_setup(&op->timer, bcm_rx_timeout_handler, CLOCK_MONOTONIC,
1195 HRTIMER_MODE_REL_SOFT);
1196 hrtimer_setup(&op->thrtimer, bcm_rx_thr_handler, CLOCK_MONOTONIC,
1197 HRTIMER_MODE_REL_SOFT);
1198
1199 /* add this bcm_op to the list of the rx_ops */
1200 list_add(&op->list, &bo->rx_ops);
1201
1202 /* call can_rx_register() */
1203 do_rx_register = 1;
1204
1205 } /* if ((op = bcm_find_op(&bo->rx_ops, msg_head->can_id, ifindex))) */
1206
1207 /* check flags */
1208
1209 if (op->flags & RX_RTR_FRAME) {
1210 struct canfd_frame *frame0 = op->frames;
1211
1212 /* no timers in RTR-mode */
1213 hrtimer_cancel(&op->thrtimer);
1214 hrtimer_cancel(&op->timer);
1215
1216 /*
1217 * funny feature in RX(!)_SETUP only for RTR-mode:
1218 * copy can_id into frame BUT without RTR-flag to
1219 * prevent a full-load-loopback-test ... ;-]
1220 */
1221 if ((op->flags & TX_CP_CAN_ID) ||
1222 (frame0->can_id == op->can_id))
1223 frame0->can_id = op->can_id & ~CAN_RTR_FLAG;
1224
1225 } else {
1226 if (op->flags & SETTIMER) {
1227
1228 /* set timer value */
1229 op->ival1 = msg_head->ival1;
1230 op->ival2 = msg_head->ival2;
1231 op->kt_ival1 = bcm_timeval_to_ktime(msg_head->ival1);
1232 op->kt_ival2 = bcm_timeval_to_ktime(msg_head->ival2);
1233
1234 /* disable an active timer due to zero value? */
1235 if (!op->kt_ival1)
1236 hrtimer_cancel(&op->timer);
1237
1238 /*
1239 * In any case cancel the throttle timer, flush
1240 * potentially blocked msgs and reset throttle handling
1241 */
1242 op->kt_lastmsg = 0;
1243 hrtimer_cancel(&op->thrtimer);
1244 bcm_rx_thr_flush(op);
1245 }
1246
1247 if ((op->flags & STARTTIMER) && op->kt_ival1)
1248 hrtimer_start(&op->timer, op->kt_ival1,
1249 HRTIMER_MODE_REL_SOFT);
1250 }
1251
1252 /* now we can register for can_ids, if we added a new bcm_op */
1253 if (do_rx_register) {
1254 if (ifindex) {
1255 struct net_device *dev;
1256
1257 dev = dev_get_by_index(sock_net(sk), ifindex);
1258 if (dev) {
1259 err = can_rx_register(sock_net(sk), dev,
1260 op->can_id,
1261 REGMASK(op->can_id),
1262 bcm_rx_handler, op,
1263 "bcm", sk);
1264
1265 op->rx_reg_dev = dev;
1266 dev_put(dev);
1267 }
1268
1269 } else
1270 err = can_rx_register(sock_net(sk), NULL, op->can_id,
1271 REGMASK(op->can_id),
1272 bcm_rx_handler, op, "bcm", sk);
1273 if (err) {
1274 /* this bcm rx op is broken -> remove it */
1275 list_del(&op->list);
1276 bcm_remove_op(op);
1277 return err;
1278 }
1279 }
1280
1281 return msg_head->nframes * op->cfsiz + MHSIZ;
1282 }
1283
1284 /*
1285 * bcm_tx_send - send a single CAN frame to the CAN interface (for bcm_sendmsg)
1286 */
bcm_tx_send(struct msghdr * msg,int ifindex,struct sock * sk,int cfsiz)1287 static int bcm_tx_send(struct msghdr *msg, int ifindex, struct sock *sk,
1288 int cfsiz)
1289 {
1290 struct sk_buff *skb;
1291 struct net_device *dev;
1292 int err;
1293
1294 /* we need a real device to send frames */
1295 if (!ifindex)
1296 return -ENODEV;
1297
1298 skb = alloc_skb(cfsiz + sizeof(struct can_skb_priv), GFP_KERNEL);
1299 if (!skb)
1300 return -ENOMEM;
1301
1302 can_skb_reserve(skb);
1303
1304 err = memcpy_from_msg(skb_put(skb, cfsiz), msg, cfsiz);
1305 if (err < 0) {
1306 kfree_skb(skb);
1307 return err;
1308 }
1309
1310 dev = dev_get_by_index(sock_net(sk), ifindex);
1311 if (!dev) {
1312 kfree_skb(skb);
1313 return -ENODEV;
1314 }
1315
1316 can_skb_prv(skb)->ifindex = dev->ifindex;
1317 can_skb_prv(skb)->skbcnt = 0;
1318 skb->dev = dev;
1319 can_skb_set_owner(skb, sk);
1320 err = can_send(skb, 1); /* send with loopback */
1321 dev_put(dev);
1322
1323 if (err)
1324 return err;
1325
1326 return cfsiz + MHSIZ;
1327 }
1328
1329 /*
1330 * bcm_sendmsg - process BCM commands (opcodes) from the userspace
1331 */
bcm_sendmsg(struct socket * sock,struct msghdr * msg,size_t size)1332 static int bcm_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
1333 {
1334 struct sock *sk = sock->sk;
1335 struct bcm_sock *bo = bcm_sk(sk);
1336 int ifindex = bo->ifindex; /* default ifindex for this bcm_op */
1337 struct bcm_msg_head msg_head;
1338 int cfsiz;
1339 int ret; /* read bytes or error codes as return value */
1340
1341 if (!bo->bound)
1342 return -ENOTCONN;
1343
1344 /* check for valid message length from userspace */
1345 if (size < MHSIZ)
1346 return -EINVAL;
1347
1348 /* read message head information */
1349 ret = memcpy_from_msg((u8 *)&msg_head, msg, MHSIZ);
1350 if (ret < 0)
1351 return ret;
1352
1353 cfsiz = CFSIZ(msg_head.flags);
1354 if ((size - MHSIZ) % cfsiz)
1355 return -EINVAL;
1356
1357 /* check for alternative ifindex for this bcm_op */
1358
1359 if (!ifindex && msg->msg_name) {
1360 /* no bound device as default => check msg_name */
1361 DECLARE_SOCKADDR(struct sockaddr_can *, addr, msg->msg_name);
1362
1363 if (msg->msg_namelen < BCM_MIN_NAMELEN)
1364 return -EINVAL;
1365
1366 if (addr->can_family != AF_CAN)
1367 return -EINVAL;
1368
1369 /* ifindex from sendto() */
1370 ifindex = addr->can_ifindex;
1371
1372 if (ifindex) {
1373 struct net_device *dev;
1374
1375 dev = dev_get_by_index(sock_net(sk), ifindex);
1376 if (!dev)
1377 return -ENODEV;
1378
1379 if (dev->type != ARPHRD_CAN) {
1380 dev_put(dev);
1381 return -ENODEV;
1382 }
1383
1384 dev_put(dev);
1385 }
1386 }
1387
1388 lock_sock(sk);
1389
1390 switch (msg_head.opcode) {
1391
1392 case TX_SETUP:
1393 ret = bcm_tx_setup(&msg_head, msg, ifindex, sk);
1394 break;
1395
1396 case RX_SETUP:
1397 ret = bcm_rx_setup(&msg_head, msg, ifindex, sk);
1398 break;
1399
1400 case TX_DELETE:
1401 if (bcm_delete_tx_op(&bo->tx_ops, &msg_head, ifindex))
1402 ret = MHSIZ;
1403 else
1404 ret = -EINVAL;
1405 break;
1406
1407 case RX_DELETE:
1408 if (bcm_delete_rx_op(&bo->rx_ops, &msg_head, ifindex))
1409 ret = MHSIZ;
1410 else
1411 ret = -EINVAL;
1412 break;
1413
1414 case TX_READ:
1415 /* reuse msg_head for the reply to TX_READ */
1416 msg_head.opcode = TX_STATUS;
1417 ret = bcm_read_op(&bo->tx_ops, &msg_head, ifindex);
1418 break;
1419
1420 case RX_READ:
1421 /* reuse msg_head for the reply to RX_READ */
1422 msg_head.opcode = RX_STATUS;
1423 ret = bcm_read_op(&bo->rx_ops, &msg_head, ifindex);
1424 break;
1425
1426 case TX_SEND:
1427 /* we need exactly one CAN frame behind the msg head */
1428 if ((msg_head.nframes != 1) || (size != cfsiz + MHSIZ))
1429 ret = -EINVAL;
1430 else
1431 ret = bcm_tx_send(msg, ifindex, sk, cfsiz);
1432 break;
1433
1434 default:
1435 ret = -EINVAL;
1436 break;
1437 }
1438
1439 release_sock(sk);
1440
1441 return ret;
1442 }
1443
1444 /*
1445 * notification handler for netdevice status changes
1446 */
bcm_notify(struct bcm_sock * bo,unsigned long msg,struct net_device * dev)1447 static void bcm_notify(struct bcm_sock *bo, unsigned long msg,
1448 struct net_device *dev)
1449 {
1450 struct sock *sk = &bo->sk;
1451 struct bcm_op *op;
1452 int notify_enodev = 0;
1453
1454 if (!net_eq(dev_net(dev), sock_net(sk)))
1455 return;
1456
1457 switch (msg) {
1458
1459 case NETDEV_UNREGISTER:
1460 lock_sock(sk);
1461
1462 /* remove device specific receive entries */
1463 list_for_each_entry(op, &bo->rx_ops, list)
1464 if (op->rx_reg_dev == dev)
1465 bcm_rx_unreg(dev, op);
1466
1467 /* remove device reference, if this is our bound device */
1468 if (bo->bound && bo->ifindex == dev->ifindex) {
1469 #if IS_ENABLED(CONFIG_PROC_FS)
1470 if (sock_net(sk)->can.bcmproc_dir && bo->bcm_proc_read) {
1471 remove_proc_entry(bo->procname, sock_net(sk)->can.bcmproc_dir);
1472 bo->bcm_proc_read = NULL;
1473 }
1474 #endif
1475 bo->bound = 0;
1476 bo->ifindex = 0;
1477 notify_enodev = 1;
1478 }
1479
1480 release_sock(sk);
1481
1482 if (notify_enodev) {
1483 sk->sk_err = ENODEV;
1484 if (!sock_flag(sk, SOCK_DEAD))
1485 sk_error_report(sk);
1486 }
1487 break;
1488
1489 case NETDEV_DOWN:
1490 if (bo->bound && bo->ifindex == dev->ifindex) {
1491 sk->sk_err = ENETDOWN;
1492 if (!sock_flag(sk, SOCK_DEAD))
1493 sk_error_report(sk);
1494 }
1495 }
1496 }
1497
bcm_notifier(struct notifier_block * nb,unsigned long msg,void * ptr)1498 static int bcm_notifier(struct notifier_block *nb, unsigned long msg,
1499 void *ptr)
1500 {
1501 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1502
1503 if (dev->type != ARPHRD_CAN)
1504 return NOTIFY_DONE;
1505 if (msg != NETDEV_UNREGISTER && msg != NETDEV_DOWN)
1506 return NOTIFY_DONE;
1507 if (unlikely(bcm_busy_notifier)) /* Check for reentrant bug. */
1508 return NOTIFY_DONE;
1509
1510 spin_lock(&bcm_notifier_lock);
1511 list_for_each_entry(bcm_busy_notifier, &bcm_notifier_list, notifier) {
1512 spin_unlock(&bcm_notifier_lock);
1513 bcm_notify(bcm_busy_notifier, msg, dev);
1514 spin_lock(&bcm_notifier_lock);
1515 }
1516 bcm_busy_notifier = NULL;
1517 spin_unlock(&bcm_notifier_lock);
1518 return NOTIFY_DONE;
1519 }
1520
1521 /*
1522 * initial settings for all BCM sockets to be set at socket creation time
1523 */
bcm_init(struct sock * sk)1524 static int bcm_init(struct sock *sk)
1525 {
1526 struct bcm_sock *bo = bcm_sk(sk);
1527
1528 bo->bound = 0;
1529 bo->ifindex = 0;
1530 bo->dropped_usr_msgs = 0;
1531 bo->bcm_proc_read = NULL;
1532
1533 INIT_LIST_HEAD(&bo->tx_ops);
1534 INIT_LIST_HEAD(&bo->rx_ops);
1535
1536 /* set notifier */
1537 spin_lock(&bcm_notifier_lock);
1538 list_add_tail(&bo->notifier, &bcm_notifier_list);
1539 spin_unlock(&bcm_notifier_lock);
1540
1541 return 0;
1542 }
1543
1544 /*
1545 * standard socket functions
1546 */
bcm_release(struct socket * sock)1547 static int bcm_release(struct socket *sock)
1548 {
1549 struct sock *sk = sock->sk;
1550 struct net *net;
1551 struct bcm_sock *bo;
1552 struct bcm_op *op, *next;
1553
1554 if (!sk)
1555 return 0;
1556
1557 net = sock_net(sk);
1558 bo = bcm_sk(sk);
1559
1560 /* remove bcm_ops, timer, rx_unregister(), etc. */
1561
1562 spin_lock(&bcm_notifier_lock);
1563 while (bcm_busy_notifier == bo) {
1564 spin_unlock(&bcm_notifier_lock);
1565 schedule_timeout_uninterruptible(1);
1566 spin_lock(&bcm_notifier_lock);
1567 }
1568 list_del(&bo->notifier);
1569 spin_unlock(&bcm_notifier_lock);
1570
1571 lock_sock(sk);
1572
1573 #if IS_ENABLED(CONFIG_PROC_FS)
1574 /* remove procfs entry */
1575 if (net->can.bcmproc_dir && bo->bcm_proc_read)
1576 remove_proc_entry(bo->procname, net->can.bcmproc_dir);
1577 #endif /* CONFIG_PROC_FS */
1578
1579 list_for_each_entry_safe(op, next, &bo->tx_ops, list)
1580 bcm_remove_op(op);
1581
1582 list_for_each_entry_safe(op, next, &bo->rx_ops, list) {
1583 /*
1584 * Don't care if we're bound or not (due to netdev problems)
1585 * can_rx_unregister() is always a save thing to do here.
1586 */
1587 if (op->ifindex) {
1588 /*
1589 * Only remove subscriptions that had not
1590 * been removed due to NETDEV_UNREGISTER
1591 * in bcm_notifier()
1592 */
1593 if (op->rx_reg_dev) {
1594 struct net_device *dev;
1595
1596 dev = dev_get_by_index(net, op->ifindex);
1597 if (dev) {
1598 bcm_rx_unreg(dev, op);
1599 dev_put(dev);
1600 }
1601 }
1602 } else
1603 can_rx_unregister(net, NULL, op->can_id,
1604 REGMASK(op->can_id),
1605 bcm_rx_handler, op);
1606
1607 }
1608
1609 synchronize_rcu();
1610
1611 list_for_each_entry_safe(op, next, &bo->rx_ops, list)
1612 bcm_remove_op(op);
1613
1614 /* remove device reference */
1615 if (bo->bound) {
1616 bo->bound = 0;
1617 bo->ifindex = 0;
1618 }
1619
1620 sock_orphan(sk);
1621 sock->sk = NULL;
1622
1623 release_sock(sk);
1624 sock_prot_inuse_add(net, sk->sk_prot, -1);
1625 sock_put(sk);
1626
1627 return 0;
1628 }
1629
bcm_connect(struct socket * sock,struct sockaddr * uaddr,int len,int flags)1630 static int bcm_connect(struct socket *sock, struct sockaddr *uaddr, int len,
1631 int flags)
1632 {
1633 struct sockaddr_can *addr = (struct sockaddr_can *)uaddr;
1634 struct sock *sk = sock->sk;
1635 struct bcm_sock *bo = bcm_sk(sk);
1636 struct net *net = sock_net(sk);
1637 int ret = 0;
1638
1639 if (len < BCM_MIN_NAMELEN)
1640 return -EINVAL;
1641
1642 lock_sock(sk);
1643
1644 if (bo->bound) {
1645 ret = -EISCONN;
1646 goto fail;
1647 }
1648
1649 /* bind a device to this socket */
1650 if (addr->can_ifindex) {
1651 struct net_device *dev;
1652
1653 dev = dev_get_by_index(net, addr->can_ifindex);
1654 if (!dev) {
1655 ret = -ENODEV;
1656 goto fail;
1657 }
1658 if (dev->type != ARPHRD_CAN) {
1659 dev_put(dev);
1660 ret = -ENODEV;
1661 goto fail;
1662 }
1663
1664 bo->ifindex = dev->ifindex;
1665 dev_put(dev);
1666
1667 } else {
1668 /* no interface reference for ifindex = 0 ('any' CAN device) */
1669 bo->ifindex = 0;
1670 }
1671
1672 #if IS_ENABLED(CONFIG_PROC_FS)
1673 if (net->can.bcmproc_dir) {
1674 /* unique socket address as filename */
1675 sprintf(bo->procname, "%lu", sock_i_ino(sk));
1676 bo->bcm_proc_read = proc_create_net_single(bo->procname, 0644,
1677 net->can.bcmproc_dir,
1678 bcm_proc_show, sk);
1679 if (!bo->bcm_proc_read) {
1680 ret = -ENOMEM;
1681 goto fail;
1682 }
1683 }
1684 #endif /* CONFIG_PROC_FS */
1685
1686 bo->bound = 1;
1687
1688 fail:
1689 release_sock(sk);
1690
1691 return ret;
1692 }
1693
bcm_recvmsg(struct socket * sock,struct msghdr * msg,size_t size,int flags)1694 static int bcm_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
1695 int flags)
1696 {
1697 struct sock *sk = sock->sk;
1698 struct sk_buff *skb;
1699 int error = 0;
1700 int err;
1701
1702 skb = skb_recv_datagram(sk, flags, &error);
1703 if (!skb)
1704 return error;
1705
1706 if (skb->len < size)
1707 size = skb->len;
1708
1709 err = memcpy_to_msg(msg, skb->data, size);
1710 if (err < 0) {
1711 skb_free_datagram(sk, skb);
1712 return err;
1713 }
1714
1715 sock_recv_cmsgs(msg, sk, skb);
1716
1717 if (msg->msg_name) {
1718 __sockaddr_check_size(BCM_MIN_NAMELEN);
1719 msg->msg_namelen = BCM_MIN_NAMELEN;
1720 memcpy(msg->msg_name, skb->cb, msg->msg_namelen);
1721 }
1722
1723 /* assign the flags that have been recorded in bcm_send_to_user() */
1724 msg->msg_flags |= *(bcm_flags(skb));
1725
1726 skb_free_datagram(sk, skb);
1727
1728 return size;
1729 }
1730
bcm_sock_no_ioctlcmd(struct socket * sock,unsigned int cmd,unsigned long arg)1731 static int bcm_sock_no_ioctlcmd(struct socket *sock, unsigned int cmd,
1732 unsigned long arg)
1733 {
1734 /* no ioctls for socket layer -> hand it down to NIC layer */
1735 return -ENOIOCTLCMD;
1736 }
1737
1738 static const struct proto_ops bcm_ops = {
1739 .family = PF_CAN,
1740 .release = bcm_release,
1741 .bind = sock_no_bind,
1742 .connect = bcm_connect,
1743 .socketpair = sock_no_socketpair,
1744 .accept = sock_no_accept,
1745 .getname = sock_no_getname,
1746 .poll = datagram_poll,
1747 .ioctl = bcm_sock_no_ioctlcmd,
1748 .gettstamp = sock_gettstamp,
1749 .listen = sock_no_listen,
1750 .shutdown = sock_no_shutdown,
1751 .sendmsg = bcm_sendmsg,
1752 .recvmsg = bcm_recvmsg,
1753 .mmap = sock_no_mmap,
1754 };
1755
1756 static struct proto bcm_proto __read_mostly = {
1757 .name = "CAN_BCM",
1758 .owner = THIS_MODULE,
1759 .obj_size = sizeof(struct bcm_sock),
1760 .init = bcm_init,
1761 };
1762
1763 static const struct can_proto bcm_can_proto = {
1764 .type = SOCK_DGRAM,
1765 .protocol = CAN_BCM,
1766 .ops = &bcm_ops,
1767 .prot = &bcm_proto,
1768 };
1769
canbcm_pernet_init(struct net * net)1770 static int canbcm_pernet_init(struct net *net)
1771 {
1772 #if IS_ENABLED(CONFIG_PROC_FS)
1773 /* create /proc/net/can-bcm directory */
1774 net->can.bcmproc_dir = proc_net_mkdir(net, "can-bcm", net->proc_net);
1775 #endif /* CONFIG_PROC_FS */
1776
1777 return 0;
1778 }
1779
canbcm_pernet_exit(struct net * net)1780 static void canbcm_pernet_exit(struct net *net)
1781 {
1782 #if IS_ENABLED(CONFIG_PROC_FS)
1783 /* remove /proc/net/can-bcm directory */
1784 if (net->can.bcmproc_dir)
1785 remove_proc_entry("can-bcm", net->proc_net);
1786 #endif /* CONFIG_PROC_FS */
1787 }
1788
1789 static struct pernet_operations canbcm_pernet_ops __read_mostly = {
1790 .init = canbcm_pernet_init,
1791 .exit = canbcm_pernet_exit,
1792 };
1793
1794 static struct notifier_block canbcm_notifier = {
1795 .notifier_call = bcm_notifier
1796 };
1797
bcm_module_init(void)1798 static int __init bcm_module_init(void)
1799 {
1800 int err;
1801
1802 pr_info("can: broadcast manager protocol\n");
1803
1804 err = register_pernet_subsys(&canbcm_pernet_ops);
1805 if (err)
1806 return err;
1807
1808 err = register_netdevice_notifier(&canbcm_notifier);
1809 if (err)
1810 goto register_notifier_failed;
1811
1812 err = can_proto_register(&bcm_can_proto);
1813 if (err < 0) {
1814 printk(KERN_ERR "can: registration of bcm protocol failed\n");
1815 goto register_proto_failed;
1816 }
1817
1818 return 0;
1819
1820 register_proto_failed:
1821 unregister_netdevice_notifier(&canbcm_notifier);
1822 register_notifier_failed:
1823 unregister_pernet_subsys(&canbcm_pernet_ops);
1824 return err;
1825 }
1826
bcm_module_exit(void)1827 static void __exit bcm_module_exit(void)
1828 {
1829 can_proto_unregister(&bcm_can_proto);
1830 unregister_netdevice_notifier(&canbcm_notifier);
1831 unregister_pernet_subsys(&canbcm_pernet_ops);
1832 }
1833
1834 module_init(bcm_module_init);
1835 module_exit(bcm_module_exit);
1836