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Linux/net/can/bcm.c

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  1 /*
  2  * bcm.c - Broadcast Manager to filter/send (cyclic) CAN content
  3  *
  4  * Copyright (c) 2002-2017 Volkswagen Group Electronic Research
  5  * All rights reserved.
  6  *
  7  * Redistribution and use in source and binary forms, with or without
  8  * modification, are permitted provided that the following conditions
  9  * are met:
 10  * 1. Redistributions of source code must retain the above copyright
 11  *    notice, this list of conditions and the following disclaimer.
 12  * 2. Redistributions in binary form must reproduce the above copyright
 13  *    notice, this list of conditions and the following disclaimer in the
 14  *    documentation and/or other materials provided with the distribution.
 15  * 3. Neither the name of Volkswagen nor the names of its contributors
 16  *    may be used to endorse or promote products derived from this software
 17  *    without specific prior written permission.
 18  *
 19  * Alternatively, provided that this notice is retained in full, this
 20  * software may be distributed under the terms of the GNU General
 21  * Public License ("GPL") version 2, in which case the provisions of the
 22  * GPL apply INSTEAD OF those given above.
 23  *
 24  * The provided data structures and external interfaces from this code
 25  * are not restricted to be used by modules with a GPL compatible license.
 26  *
 27  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 28  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 29  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 30  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 31  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 32  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 33  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 34  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 35  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 36  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 37  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
 38  * DAMAGE.
 39  *
 40  */
 41 
 42 #include <linux/module.h>
 43 #include <linux/init.h>
 44 #include <linux/interrupt.h>
 45 #include <linux/hrtimer.h>
 46 #include <linux/list.h>
 47 #include <linux/proc_fs.h>
 48 #include <linux/seq_file.h>
 49 #include <linux/uio.h>
 50 #include <linux/net.h>
 51 #include <linux/netdevice.h>
 52 #include <linux/socket.h>
 53 #include <linux/if_arp.h>
 54 #include <linux/skbuff.h>
 55 #include <linux/can.h>
 56 #include <linux/can/core.h>
 57 #include <linux/can/skb.h>
 58 #include <linux/can/bcm.h>
 59 #include <linux/slab.h>
 60 #include <net/sock.h>
 61 #include <net/net_namespace.h>
 62 
 63 /*
 64  * To send multiple CAN frame content within TX_SETUP or to filter
 65  * CAN messages with multiplex index within RX_SETUP, the number of
 66  * different filters is limited to 256 due to the one byte index value.
 67  */
 68 #define MAX_NFRAMES 256
 69 
 70 /* use of last_frames[index].flags */
 71 #define RX_RECV    0x40 /* received data for this element */
 72 #define RX_THR     0x80 /* element not been sent due to throttle feature */
 73 #define BCM_CAN_FLAGS_MASK 0x3F /* to clean private flags after usage */
 74 
 75 /* get best masking value for can_rx_register() for a given single can_id */
 76 #define REGMASK(id) ((id & CAN_EFF_FLAG) ? \
 77                      (CAN_EFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG) : \
 78                      (CAN_SFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG))
 79 
 80 #define CAN_BCM_VERSION "20170425"
 81 
 82 MODULE_DESCRIPTION("PF_CAN broadcast manager protocol");
 83 MODULE_LICENSE("Dual BSD/GPL");
 84 MODULE_AUTHOR("Oliver Hartkopp <oliver.hartkopp@volkswagen.de>");
 85 MODULE_ALIAS("can-proto-2");
 86 
 87 /*
 88  * easy access to the first 64 bit of can(fd)_frame payload. cp->data is
 89  * 64 bit aligned so the offset has to be multiples of 8 which is ensured
 90  * by the only callers in bcm_rx_cmp_to_index() bcm_rx_handler().
 91  */
 92 static inline u64 get_u64(const struct canfd_frame *cp, int offset)
 93 {
 94         return *(u64 *)(cp->data + offset);
 95 }
 96 
 97 struct bcm_op {
 98         struct list_head list;
 99         int ifindex;
100         canid_t can_id;
101         u32 flags;
102         unsigned long frames_abs, frames_filtered;
103         struct bcm_timeval ival1, ival2;
104         struct hrtimer timer, thrtimer;
105         struct tasklet_struct tsklet, thrtsklet;
106         ktime_t rx_stamp, kt_ival1, kt_ival2, kt_lastmsg;
107         int rx_ifindex;
108         int cfsiz;
109         u32 count;
110         u32 nframes;
111         u32 currframe;
112         /* void pointers to arrays of struct can[fd]_frame */
113         void *frames;
114         void *last_frames;
115         struct canfd_frame sframe;
116         struct canfd_frame last_sframe;
117         struct sock *sk;
118         struct net_device *rx_reg_dev;
119 };
120 
121 struct bcm_sock {
122         struct sock sk;
123         int bound;
124         int ifindex;
125         struct notifier_block notifier;
126         struct list_head rx_ops;
127         struct list_head tx_ops;
128         unsigned long dropped_usr_msgs;
129         struct proc_dir_entry *bcm_proc_read;
130         char procname [32]; /* inode number in decimal with \0 */
131 };
132 
133 static inline struct bcm_sock *bcm_sk(const struct sock *sk)
134 {
135         return (struct bcm_sock *)sk;
136 }
137 
138 static inline ktime_t bcm_timeval_to_ktime(struct bcm_timeval tv)
139 {
140         return ktime_set(tv.tv_sec, tv.tv_usec * NSEC_PER_USEC);
141 }
142 
143 #define CFSIZ(flags) ((flags & CAN_FD_FRAME) ? CANFD_MTU : CAN_MTU)
144 #define OPSIZ sizeof(struct bcm_op)
145 #define MHSIZ sizeof(struct bcm_msg_head)
146 
147 /*
148  * procfs functions
149  */
150 #if IS_ENABLED(CONFIG_PROC_FS)
151 static char *bcm_proc_getifname(struct net *net, char *result, int ifindex)
152 {
153         struct net_device *dev;
154 
155         if (!ifindex)
156                 return "any";
157 
158         rcu_read_lock();
159         dev = dev_get_by_index_rcu(net, ifindex);
160         if (dev)
161                 strcpy(result, dev->name);
162         else
163                 strcpy(result, "???");
164         rcu_read_unlock();
165 
166         return result;
167 }
168 
169 static int bcm_proc_show(struct seq_file *m, void *v)
170 {
171         char ifname[IFNAMSIZ];
172         struct net *net = m->private;
173         struct sock *sk = (struct sock *)PDE_DATA(m->file->f_inode);
174         struct bcm_sock *bo = bcm_sk(sk);
175         struct bcm_op *op;
176 
177         seq_printf(m, ">>> socket %pK", sk->sk_socket);
178         seq_printf(m, " / sk %pK", sk);
179         seq_printf(m, " / bo %pK", bo);
180         seq_printf(m, " / dropped %lu", bo->dropped_usr_msgs);
181         seq_printf(m, " / bound %s", bcm_proc_getifname(net, ifname, bo->ifindex));
182         seq_printf(m, " <<<\n");
183 
184         list_for_each_entry(op, &bo->rx_ops, list) {
185 
186                 unsigned long reduction;
187 
188                 /* print only active entries & prevent division by zero */
189                 if (!op->frames_abs)
190                         continue;
191 
192                 seq_printf(m, "rx_op: %03X %-5s ", op->can_id,
193                            bcm_proc_getifname(net, ifname, op->ifindex));
194 
195                 if (op->flags & CAN_FD_FRAME)
196                         seq_printf(m, "(%u)", op->nframes);
197                 else
198                         seq_printf(m, "[%u]", op->nframes);
199 
200                 seq_printf(m, "%c ", (op->flags & RX_CHECK_DLC) ? 'd' : ' ');
201 
202                 if (op->kt_ival1)
203                         seq_printf(m, "timeo=%lld ",
204                                    (long long)ktime_to_us(op->kt_ival1));
205 
206                 if (op->kt_ival2)
207                         seq_printf(m, "thr=%lld ",
208                                    (long long)ktime_to_us(op->kt_ival2));
209 
210                 seq_printf(m, "# recv %ld (%ld) => reduction: ",
211                            op->frames_filtered, op->frames_abs);
212 
213                 reduction = 100 - (op->frames_filtered * 100) / op->frames_abs;
214 
215                 seq_printf(m, "%s%ld%%\n",
216                            (reduction == 100) ? "near " : "", reduction);
217         }
218 
219         list_for_each_entry(op, &bo->tx_ops, list) {
220 
221                 seq_printf(m, "tx_op: %03X %s ", op->can_id,
222                            bcm_proc_getifname(net, ifname, op->ifindex));
223 
224                 if (op->flags & CAN_FD_FRAME)
225                         seq_printf(m, "(%u) ", op->nframes);
226                 else
227                         seq_printf(m, "[%u] ", op->nframes);
228 
229                 if (op->kt_ival1)
230                         seq_printf(m, "t1=%lld ",
231                                    (long long)ktime_to_us(op->kt_ival1));
232 
233                 if (op->kt_ival2)
234                         seq_printf(m, "t2=%lld ",
235                                    (long long)ktime_to_us(op->kt_ival2));
236 
237                 seq_printf(m, "# sent %ld\n", op->frames_abs);
238         }
239         seq_putc(m, '\n');
240         return 0;
241 }
242 #endif /* CONFIG_PROC_FS */
243 
244 /*
245  * bcm_can_tx - send the (next) CAN frame to the appropriate CAN interface
246  *              of the given bcm tx op
247  */
248 static void bcm_can_tx(struct bcm_op *op)
249 {
250         struct sk_buff *skb;
251         struct net_device *dev;
252         struct canfd_frame *cf = op->frames + op->cfsiz * op->currframe;
253 
254         /* no target device? => exit */
255         if (!op->ifindex)
256                 return;
257 
258         dev = dev_get_by_index(sock_net(op->sk), op->ifindex);
259         if (!dev) {
260                 /* RFC: should this bcm_op remove itself here? */
261                 return;
262         }
263 
264         skb = alloc_skb(op->cfsiz + sizeof(struct can_skb_priv), gfp_any());
265         if (!skb)
266                 goto out;
267 
268         can_skb_reserve(skb);
269         can_skb_prv(skb)->ifindex = dev->ifindex;
270         can_skb_prv(skb)->skbcnt = 0;
271 
272         skb_put_data(skb, cf, op->cfsiz);
273 
274         /* send with loopback */
275         skb->dev = dev;
276         can_skb_set_owner(skb, op->sk);
277         can_send(skb, 1);
278 
279         /* update statistics */
280         op->currframe++;
281         op->frames_abs++;
282 
283         /* reached last frame? */
284         if (op->currframe >= op->nframes)
285                 op->currframe = 0;
286 out:
287         dev_put(dev);
288 }
289 
290 /*
291  * bcm_send_to_user - send a BCM message to the userspace
292  *                    (consisting of bcm_msg_head + x CAN frames)
293  */
294 static void bcm_send_to_user(struct bcm_op *op, struct bcm_msg_head *head,
295                              struct canfd_frame *frames, int has_timestamp)
296 {
297         struct sk_buff *skb;
298         struct canfd_frame *firstframe;
299         struct sockaddr_can *addr;
300         struct sock *sk = op->sk;
301         unsigned int datalen = head->nframes * op->cfsiz;
302         int err;
303 
304         skb = alloc_skb(sizeof(*head) + datalen, gfp_any());
305         if (!skb)
306                 return;
307 
308         skb_put_data(skb, head, sizeof(*head));
309 
310         if (head->nframes) {
311                 /* CAN frames starting here */
312                 firstframe = (struct canfd_frame *)skb_tail_pointer(skb);
313 
314                 skb_put_data(skb, frames, datalen);
315 
316                 /*
317                  * the BCM uses the flags-element of the canfd_frame
318                  * structure for internal purposes. This is only
319                  * relevant for updates that are generated by the
320                  * BCM, where nframes is 1
321                  */
322                 if (head->nframes == 1)
323                         firstframe->flags &= BCM_CAN_FLAGS_MASK;
324         }
325 
326         if (has_timestamp) {
327                 /* restore rx timestamp */
328                 skb->tstamp = op->rx_stamp;
329         }
330 
331         /*
332          *  Put the datagram to the queue so that bcm_recvmsg() can
333          *  get it from there.  We need to pass the interface index to
334          *  bcm_recvmsg().  We pass a whole struct sockaddr_can in skb->cb
335          *  containing the interface index.
336          */
337 
338         sock_skb_cb_check_size(sizeof(struct sockaddr_can));
339         addr = (struct sockaddr_can *)skb->cb;
340         memset(addr, 0, sizeof(*addr));
341         addr->can_family  = AF_CAN;
342         addr->can_ifindex = op->rx_ifindex;
343 
344         err = sock_queue_rcv_skb(sk, skb);
345         if (err < 0) {
346                 struct bcm_sock *bo = bcm_sk(sk);
347 
348                 kfree_skb(skb);
349                 /* don't care about overflows in this statistic */
350                 bo->dropped_usr_msgs++;
351         }
352 }
353 
354 static void bcm_tx_start_timer(struct bcm_op *op)
355 {
356         if (op->kt_ival1 && op->count)
357                 hrtimer_start(&op->timer,
358                               ktime_add(ktime_get(), op->kt_ival1),
359                               HRTIMER_MODE_ABS);
360         else if (op->kt_ival2)
361                 hrtimer_start(&op->timer,
362                               ktime_add(ktime_get(), op->kt_ival2),
363                               HRTIMER_MODE_ABS);
364 }
365 
366 static void bcm_tx_timeout_tsklet(unsigned long data)
367 {
368         struct bcm_op *op = (struct bcm_op *)data;
369         struct bcm_msg_head msg_head;
370 
371         if (op->kt_ival1 && (op->count > 0)) {
372 
373                 op->count--;
374                 if (!op->count && (op->flags & TX_COUNTEVT)) {
375 
376                         /* create notification to user */
377                         msg_head.opcode  = TX_EXPIRED;
378                         msg_head.flags   = op->flags;
379                         msg_head.count   = op->count;
380                         msg_head.ival1   = op->ival1;
381                         msg_head.ival2   = op->ival2;
382                         msg_head.can_id  = op->can_id;
383                         msg_head.nframes = 0;
384 
385                         bcm_send_to_user(op, &msg_head, NULL, 0);
386                 }
387                 bcm_can_tx(op);
388 
389         } else if (op->kt_ival2)
390                 bcm_can_tx(op);
391 
392         bcm_tx_start_timer(op);
393 }
394 
395 /*
396  * bcm_tx_timeout_handler - performs cyclic CAN frame transmissions
397  */
398 static enum hrtimer_restart bcm_tx_timeout_handler(struct hrtimer *hrtimer)
399 {
400         struct bcm_op *op = container_of(hrtimer, struct bcm_op, timer);
401 
402         tasklet_schedule(&op->tsklet);
403 
404         return HRTIMER_NORESTART;
405 }
406 
407 /*
408  * bcm_rx_changed - create a RX_CHANGED notification due to changed content
409  */
410 static void bcm_rx_changed(struct bcm_op *op, struct canfd_frame *data)
411 {
412         struct bcm_msg_head head;
413 
414         /* update statistics */
415         op->frames_filtered++;
416 
417         /* prevent statistics overflow */
418         if (op->frames_filtered > ULONG_MAX/100)
419                 op->frames_filtered = op->frames_abs = 0;
420 
421         /* this element is not throttled anymore */
422         data->flags &= (BCM_CAN_FLAGS_MASK|RX_RECV);
423 
424         head.opcode  = RX_CHANGED;
425         head.flags   = op->flags;
426         head.count   = op->count;
427         head.ival1   = op->ival1;
428         head.ival2   = op->ival2;
429         head.can_id  = op->can_id;
430         head.nframes = 1;
431 
432         bcm_send_to_user(op, &head, data, 1);
433 }
434 
435 /*
436  * bcm_rx_update_and_send - process a detected relevant receive content change
437  *                          1. update the last received data
438  *                          2. send a notification to the user (if possible)
439  */
440 static void bcm_rx_update_and_send(struct bcm_op *op,
441                                    struct canfd_frame *lastdata,
442                                    const struct canfd_frame *rxdata)
443 {
444         memcpy(lastdata, rxdata, op->cfsiz);
445 
446         /* mark as used and throttled by default */
447         lastdata->flags |= (RX_RECV|RX_THR);
448 
449         /* throttling mode inactive ? */
450         if (!op->kt_ival2) {
451                 /* send RX_CHANGED to the user immediately */
452                 bcm_rx_changed(op, lastdata);
453                 return;
454         }
455 
456         /* with active throttling timer we are just done here */
457         if (hrtimer_active(&op->thrtimer))
458                 return;
459 
460         /* first reception with enabled throttling mode */
461         if (!op->kt_lastmsg)
462                 goto rx_changed_settime;
463 
464         /* got a second frame inside a potential throttle period? */
465         if (ktime_us_delta(ktime_get(), op->kt_lastmsg) <
466             ktime_to_us(op->kt_ival2)) {
467                 /* do not send the saved data - only start throttle timer */
468                 hrtimer_start(&op->thrtimer,
469                               ktime_add(op->kt_lastmsg, op->kt_ival2),
470                               HRTIMER_MODE_ABS);
471                 return;
472         }
473 
474         /* the gap was that big, that throttling was not needed here */
475 rx_changed_settime:
476         bcm_rx_changed(op, lastdata);
477         op->kt_lastmsg = ktime_get();
478 }
479 
480 /*
481  * bcm_rx_cmp_to_index - (bit)compares the currently received data to formerly
482  *                       received data stored in op->last_frames[]
483  */
484 static void bcm_rx_cmp_to_index(struct bcm_op *op, unsigned int index,
485                                 const struct canfd_frame *rxdata)
486 {
487         struct canfd_frame *cf = op->frames + op->cfsiz * index;
488         struct canfd_frame *lcf = op->last_frames + op->cfsiz * index;
489         int i;
490 
491         /*
492          * no one uses the MSBs of flags for comparison,
493          * so we use it here to detect the first time of reception
494          */
495 
496         if (!(lcf->flags & RX_RECV)) {
497                 /* received data for the first time => send update to user */
498                 bcm_rx_update_and_send(op, lcf, rxdata);
499                 return;
500         }
501 
502         /* do a real check in CAN frame data section */
503         for (i = 0; i < rxdata->len; i += 8) {
504                 if ((get_u64(cf, i) & get_u64(rxdata, i)) !=
505                     (get_u64(cf, i) & get_u64(lcf, i))) {
506                         bcm_rx_update_and_send(op, lcf, rxdata);
507                         return;
508                 }
509         }
510 
511         if (op->flags & RX_CHECK_DLC) {
512                 /* do a real check in CAN frame length */
513                 if (rxdata->len != lcf->len) {
514                         bcm_rx_update_and_send(op, lcf, rxdata);
515                         return;
516                 }
517         }
518 }
519 
520 /*
521  * bcm_rx_starttimer - enable timeout monitoring for CAN frame reception
522  */
523 static void bcm_rx_starttimer(struct bcm_op *op)
524 {
525         if (op->flags & RX_NO_AUTOTIMER)
526                 return;
527 
528         if (op->kt_ival1)
529                 hrtimer_start(&op->timer, op->kt_ival1, HRTIMER_MODE_REL);
530 }
531 
532 static void bcm_rx_timeout_tsklet(unsigned long data)
533 {
534         struct bcm_op *op = (struct bcm_op *)data;
535         struct bcm_msg_head msg_head;
536 
537         /* create notification to user */
538         msg_head.opcode  = RX_TIMEOUT;
539         msg_head.flags   = op->flags;
540         msg_head.count   = op->count;
541         msg_head.ival1   = op->ival1;
542         msg_head.ival2   = op->ival2;
543         msg_head.can_id  = op->can_id;
544         msg_head.nframes = 0;
545 
546         bcm_send_to_user(op, &msg_head, NULL, 0);
547 }
548 
549 /*
550  * bcm_rx_timeout_handler - when the (cyclic) CAN frame reception timed out
551  */
552 static enum hrtimer_restart bcm_rx_timeout_handler(struct hrtimer *hrtimer)
553 {
554         struct bcm_op *op = container_of(hrtimer, struct bcm_op, timer);
555 
556         /* schedule before NET_RX_SOFTIRQ */
557         tasklet_hi_schedule(&op->tsklet);
558 
559         /* no restart of the timer is done here! */
560 
561         /* if user wants to be informed, when cyclic CAN-Messages come back */
562         if ((op->flags & RX_ANNOUNCE_RESUME) && op->last_frames) {
563                 /* clear received CAN frames to indicate 'nothing received' */
564                 memset(op->last_frames, 0, op->nframes * op->cfsiz);
565         }
566 
567         return HRTIMER_NORESTART;
568 }
569 
570 /*
571  * bcm_rx_do_flush - helper for bcm_rx_thr_flush
572  */
573 static inline int bcm_rx_do_flush(struct bcm_op *op, int update,
574                                   unsigned int index)
575 {
576         struct canfd_frame *lcf = op->last_frames + op->cfsiz * index;
577 
578         if ((op->last_frames) && (lcf->flags & RX_THR)) {
579                 if (update)
580                         bcm_rx_changed(op, lcf);
581                 return 1;
582         }
583         return 0;
584 }
585 
586 /*
587  * bcm_rx_thr_flush - Check for throttled data and send it to the userspace
588  *
589  * update == 0 : just check if throttled data is available  (any irq context)
590  * update == 1 : check and send throttled data to userspace (soft_irq context)
591  */
592 static int bcm_rx_thr_flush(struct bcm_op *op, int update)
593 {
594         int updated = 0;
595 
596         if (op->nframes > 1) {
597                 unsigned int i;
598 
599                 /* for MUX filter we start at index 1 */
600                 for (i = 1; i < op->nframes; i++)
601                         updated += bcm_rx_do_flush(op, update, i);
602 
603         } else {
604                 /* for RX_FILTER_ID and simple filter */
605                 updated += bcm_rx_do_flush(op, update, 0);
606         }
607 
608         return updated;
609 }
610 
611 static void bcm_rx_thr_tsklet(unsigned long data)
612 {
613         struct bcm_op *op = (struct bcm_op *)data;
614 
615         /* push the changed data to the userspace */
616         bcm_rx_thr_flush(op, 1);
617 }
618 
619 /*
620  * bcm_rx_thr_handler - the time for blocked content updates is over now:
621  *                      Check for throttled data and send it to the userspace
622  */
623 static enum hrtimer_restart bcm_rx_thr_handler(struct hrtimer *hrtimer)
624 {
625         struct bcm_op *op = container_of(hrtimer, struct bcm_op, thrtimer);
626 
627         tasklet_schedule(&op->thrtsklet);
628 
629         if (bcm_rx_thr_flush(op, 0)) {
630                 hrtimer_forward(hrtimer, ktime_get(), 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 (skb->len != op->cfsiz)
653                 return;
654 
655         /* disable timeout */
656         hrtimer_cancel(&op->timer);
657 
658         /* save rx timestamp */
659         op->rx_stamp = skb->tstamp;
660         /* save originator for recvfrom() */
661         op->rx_ifindex = skb->dev->ifindex;
662         /* update statistics */
663         op->frames_abs++;
664 
665         if (op->flags & RX_RTR_FRAME) {
666                 /* send reply for RTR-request (placed in op->frames[0]) */
667                 bcm_can_tx(op);
668                 return;
669         }
670 
671         if (op->flags & RX_FILTER_ID) {
672                 /* the easiest case */
673                 bcm_rx_update_and_send(op, op->last_frames, rxframe);
674                 goto rx_starttimer;
675         }
676 
677         if (op->nframes == 1) {
678                 /* simple compare with index 0 */
679                 bcm_rx_cmp_to_index(op, 0, rxframe);
680                 goto rx_starttimer;
681         }
682 
683         if (op->nframes > 1) {
684                 /*
685                  * multiplex compare
686                  *
687                  * find the first multiplex mask that fits.
688                  * Remark: The MUX-mask is stored in index 0 - but only the
689                  * first 64 bits of the frame data[] are relevant (CAN FD)
690                  */
691 
692                 for (i = 1; i < op->nframes; i++) {
693                         if ((get_u64(op->frames, 0) & get_u64(rxframe, 0)) ==
694                             (get_u64(op->frames, 0) &
695                              get_u64(op->frames + op->cfsiz * i, 0))) {
696                                 bcm_rx_cmp_to_index(op, i, rxframe);
697                                 break;
698                         }
699                 }
700         }
701 
702 rx_starttimer:
703         bcm_rx_starttimer(op);
704 }
705 
706 /*
707  * helpers for bcm_op handling: find & delete bcm [rx|tx] op elements
708  */
709 static struct bcm_op *bcm_find_op(struct list_head *ops,
710                                   struct bcm_msg_head *mh, int ifindex)
711 {
712         struct bcm_op *op;
713 
714         list_for_each_entry(op, ops, list) {
715                 if ((op->can_id == mh->can_id) && (op->ifindex == ifindex) &&
716                     (op->flags & CAN_FD_FRAME) == (mh->flags & CAN_FD_FRAME))
717                         return op;
718         }
719 
720         return NULL;
721 }
722 
723 static void bcm_remove_op(struct bcm_op *op)
724 {
725         if (op->tsklet.func) {
726                 while (test_bit(TASKLET_STATE_SCHED, &op->tsklet.state) ||
727                        test_bit(TASKLET_STATE_RUN, &op->tsklet.state) ||
728                        hrtimer_active(&op->timer)) {
729                         hrtimer_cancel(&op->timer);
730                         tasklet_kill(&op->tsklet);
731                 }
732         }
733 
734         if (op->thrtsklet.func) {
735                 while (test_bit(TASKLET_STATE_SCHED, &op->thrtsklet.state) ||
736                        test_bit(TASKLET_STATE_RUN, &op->thrtsklet.state) ||
737                        hrtimer_active(&op->thrtimer)) {
738                         hrtimer_cancel(&op->thrtimer);
739                         tasklet_kill(&op->thrtsklet);
740                 }
741         }
742 
743         if ((op->frames) && (op->frames != &op->sframe))
744                 kfree(op->frames);
745 
746         if ((op->last_frames) && (op->last_frames != &op->last_sframe))
747                 kfree(op->last_frames);
748 
749         kfree(op);
750 }
751 
752 static void bcm_rx_unreg(struct net_device *dev, struct bcm_op *op)
753 {
754         if (op->rx_reg_dev == dev) {
755                 can_rx_unregister(dev_net(dev), dev, op->can_id,
756                                   REGMASK(op->can_id), bcm_rx_handler, op);
757 
758                 /* mark as removed subscription */
759                 op->rx_reg_dev = NULL;
760         } else
761                 printk(KERN_ERR "can-bcm: bcm_rx_unreg: registered device "
762                        "mismatch %p %p\n", op->rx_reg_dev, dev);
763 }
764 
765 /*
766  * bcm_delete_rx_op - find and remove a rx op (returns number of removed ops)
767  */
768 static int bcm_delete_rx_op(struct list_head *ops, struct bcm_msg_head *mh,
769                             int ifindex)
770 {
771         struct bcm_op *op, *n;
772 
773         list_for_each_entry_safe(op, n, ops, list) {
774                 if ((op->can_id == mh->can_id) && (op->ifindex == ifindex) &&
775                     (op->flags & CAN_FD_FRAME) == (mh->flags & CAN_FD_FRAME)) {
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(sock_net(op->sk),
792                                                                op->ifindex);
793                                         if (dev) {
794                                                 bcm_rx_unreg(dev, op);
795                                                 dev_put(dev);
796                                         }
797                                 }
798                         } else
799                                 can_rx_unregister(sock_net(op->sk), NULL,
800                                                   op->can_id,
801                                                   REGMASK(op->can_id),
802                                                   bcm_rx_handler, op);
803 
804                         list_del(&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(&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, 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, msg_head, op->frames, 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 the given can_id */
877         op = bcm_find_op(&bo->tx_ops, msg_head, ifindex);
878         if (op) {
879                 /* update existing BCM operation */
880 
881                 /*
882                  * Do we need more space for the CAN frames than currently
883                  * allocated? -> This is a _really_ unusual use-case and
884                  * therefore (complexity / locking) it is not supported.
885                  */
886                 if (msg_head->nframes > op->nframes)
887                         return -E2BIG;
888 
889                 /* update CAN frames content */
890                 for (i = 0; i < msg_head->nframes; i++) {
891 
892                         cf = op->frames + op->cfsiz * i;
893                         err = memcpy_from_msg((u8 *)cf, msg, op->cfsiz);
894 
895                         if (op->flags & CAN_FD_FRAME) {
896                                 if (cf->len > 64)
897                                         err = -EINVAL;
898                         } else {
899                                 if (cf->len > 8)
900                                         err = -EINVAL;
901                         }
902 
903                         if (err < 0)
904                                 return err;
905 
906                         if (msg_head->flags & TX_CP_CAN_ID) {
907                                 /* copy can_id into frame */
908                                 cf->can_id = msg_head->can_id;
909                         }
910                 }
911                 op->flags = msg_head->flags;
912 
913         } else {
914                 /* insert new BCM operation for the given can_id */
915 
916                 op = kzalloc(OPSIZ, GFP_KERNEL);
917                 if (!op)
918                         return -ENOMEM;
919 
920                 op->can_id = msg_head->can_id;
921                 op->cfsiz = CFSIZ(msg_head->flags);
922                 op->flags = msg_head->flags;
923 
924                 /* create array for CAN frames and copy the data */
925                 if (msg_head->nframes > 1) {
926                         op->frames = kmalloc_array(msg_head->nframes,
927                                                    op->cfsiz,
928                                                    GFP_KERNEL);
929                         if (!op->frames) {
930                                 kfree(op);
931                                 return -ENOMEM;
932                         }
933                 } else
934                         op->frames = &op->sframe;
935 
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                                 if (op->frames != &op->sframe)
951                                         kfree(op->frames);
952                                 kfree(op);
953                                 return err;
954                         }
955 
956                         if (msg_head->flags & TX_CP_CAN_ID) {
957                                 /* copy can_id into frame */
958                                 cf->can_id = msg_head->can_id;
959                         }
960                 }
961 
962                 /* tx_ops never compare with previous received messages */
963                 op->last_frames = NULL;
964 
965                 /* bcm_can_tx / bcm_tx_timeout_handler needs this */
966                 op->sk = sk;
967                 op->ifindex = ifindex;
968 
969                 /* initialize uninitialized (kzalloc) structure */
970                 hrtimer_init(&op->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
971                 op->timer.function = bcm_tx_timeout_handler;
972 
973                 /* initialize tasklet for tx countevent notification */
974                 tasklet_init(&op->tsklet, bcm_tx_timeout_tsklet,
975                              (unsigned long) op);
976 
977                 /* currently unused in tx_ops */
978                 hrtimer_init(&op->thrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
979 
980                 /* add this bcm_op to the list of the tx_ops */
981                 list_add(&op->list, &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(msg_head->ival1);
1004                 op->kt_ival2 = bcm_timeval_to_ktime(msg_head->ival2);
1005 
1006                 /* disable an active timer due to zero values? */
1007                 if (!op->kt_ival1 && !op->kt_ival2)
1008                         hrtimer_cancel(&op->timer);
1009         }
1010 
1011         if (op->flags & STARTTIMER) {
1012                 hrtimer_cancel(&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 
1029 /*
1030  * bcm_rx_setup - create or update a bcm rx op (for bcm_sendmsg)
1031  */
1032 static int bcm_rx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
1033                         int ifindex, struct sock *sk)
1034 {
1035         struct bcm_sock *bo = bcm_sk(sk);
1036         struct bcm_op *op;
1037         int do_rx_register;
1038         int err = 0;
1039 
1040         if ((msg_head->flags & RX_FILTER_ID) || (!(msg_head->nframes))) {
1041                 /* be robust against wrong usage ... */
1042                 msg_head->flags |= RX_FILTER_ID;
1043                 /* ignore trailing garbage */
1044                 msg_head->nframes = 0;
1045         }
1046 
1047         /* the first element contains the mux-mask => MAX_NFRAMES + 1  */
1048         if (msg_head->nframes > MAX_NFRAMES + 1)
1049                 return -EINVAL;
1050 
1051         if ((msg_head->flags & RX_RTR_FRAME) &&
1052             ((msg_head->nframes != 1) ||
1053              (!(msg_head->can_id & CAN_RTR_FLAG))))
1054                 return -EINVAL;
1055 
1056         /* check the given can_id */
1057         op = bcm_find_op(&bo->rx_ops, msg_head, ifindex);
1058         if (op) {
1059                 /* update existing BCM operation */
1060 
1061                 /*
1062                  * Do we need more space for the CAN frames than currently
1063                  * allocated? -> This is a _really_ unusual use-case and
1064                  * therefore (complexity / locking) it is not supported.
1065                  */
1066                 if (msg_head->nframes > op->nframes)
1067                         return -E2BIG;
1068 
1069                 if (msg_head->nframes) {
1070                         /* update CAN frames content */
1071                         err = memcpy_from_msg(op->frames, msg,
1072                                               msg_head->nframes * op->cfsiz);
1073                         if (err < 0)
1074                                 return err;
1075 
1076                         /* clear last_frames to indicate 'nothing received' */
1077                         memset(op->last_frames, 0, msg_head->nframes * op->cfsiz);
1078                 }
1079 
1080                 op->nframes = msg_head->nframes;
1081                 op->flags = msg_head->flags;
1082 
1083                 /* Only an update -> do not call can_rx_register() */
1084                 do_rx_register = 0;
1085 
1086         } else {
1087                 /* insert new BCM operation for the given can_id */
1088                 op = kzalloc(OPSIZ, GFP_KERNEL);
1089                 if (!op)
1090                         return -ENOMEM;
1091 
1092                 op->can_id = msg_head->can_id;
1093                 op->nframes = msg_head->nframes;
1094                 op->cfsiz = CFSIZ(msg_head->flags);
1095                 op->flags = msg_head->flags;
1096 
1097                 if (msg_head->nframes > 1) {
1098                         /* create array for CAN frames and copy the data */
1099                         op->frames = kmalloc_array(msg_head->nframes,
1100                                                    op->cfsiz,
1101                                                    GFP_KERNEL);
1102                         if (!op->frames) {
1103                                 kfree(op);
1104                                 return -ENOMEM;
1105                         }
1106 
1107                         /* create and init array for received CAN frames */
1108                         op->last_frames = kcalloc(msg_head->nframes,
1109                                                   op->cfsiz,
1110                                                   GFP_KERNEL);
1111                         if (!op->last_frames) {
1112                                 kfree(op->frames);
1113                                 kfree(op);
1114                                 return -ENOMEM;
1115                         }
1116 
1117                 } else {
1118                         op->frames = &op->sframe;
1119                         op->last_frames = &op->last_sframe;
1120                 }
1121 
1122                 if (msg_head->nframes) {
1123                         err = memcpy_from_msg(op->frames, msg,
1124                                               msg_head->nframes * op->cfsiz);
1125                         if (err < 0) {
1126                                 if (op->frames != &op->sframe)
1127                                         kfree(op->frames);
1128                                 if (op->last_frames != &op->last_sframe)
1129                                         kfree(op->last_frames);
1130                                 kfree(op);
1131                                 return err;
1132                         }
1133                 }
1134 
1135                 /* bcm_can_tx / bcm_tx_timeout_handler needs this */
1136                 op->sk = sk;
1137                 op->ifindex = ifindex;
1138 
1139                 /* ifindex for timeout events w/o previous frame reception */
1140                 op->rx_ifindex = ifindex;
1141 
1142                 /* initialize uninitialized (kzalloc) structure */
1143                 hrtimer_init(&op->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1144                 op->timer.function = bcm_rx_timeout_handler;
1145 
1146                 /* initialize tasklet for rx timeout notification */
1147                 tasklet_init(&op->tsklet, bcm_rx_timeout_tsklet,
1148                              (unsigned long) op);
1149 
1150                 hrtimer_init(&op->thrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1151                 op->thrtimer.function = bcm_rx_thr_handler;
1152 
1153                 /* initialize tasklet for rx throttle handling */
1154                 tasklet_init(&op->thrtsklet, bcm_rx_thr_tsklet,
1155                              (unsigned long) op);
1156 
1157                 /* add this bcm_op to the list of the rx_ops */
1158                 list_add(&op->list, &bo->rx_ops);
1159 
1160                 /* call can_rx_register() */
1161                 do_rx_register = 1;
1162 
1163         } /* if ((op = bcm_find_op(&bo->rx_ops, msg_head->can_id, ifindex))) */
1164 
1165         /* check flags */
1166 
1167         if (op->flags & RX_RTR_FRAME) {
1168                 struct canfd_frame *frame0 = op->frames;
1169 
1170                 /* no timers in RTR-mode */
1171                 hrtimer_cancel(&op->thrtimer);
1172                 hrtimer_cancel(&op->timer);
1173 
1174                 /*
1175                  * funny feature in RX(!)_SETUP only for RTR-mode:
1176                  * copy can_id into frame BUT without RTR-flag to
1177                  * prevent a full-load-loopback-test ... ;-]
1178                  */
1179                 if ((op->flags & TX_CP_CAN_ID) ||
1180                     (frame0->can_id == op->can_id))
1181                         frame0->can_id = op->can_id & ~CAN_RTR_FLAG;
1182 
1183         } else {
1184                 if (op->flags & SETTIMER) {
1185 
1186                         /* set timer value */
1187                         op->ival1 = msg_head->ival1;
1188                         op->ival2 = msg_head->ival2;
1189                         op->kt_ival1 = bcm_timeval_to_ktime(msg_head->ival1);
1190                         op->kt_ival2 = bcm_timeval_to_ktime(msg_head->ival2);
1191 
1192                         /* disable an active timer due to zero value? */
1193                         if (!op->kt_ival1)
1194                                 hrtimer_cancel(&op->timer);
1195 
1196                         /*
1197                          * In any case cancel the throttle timer, flush
1198                          * potentially blocked msgs and reset throttle handling
1199                          */
1200                         op->kt_lastmsg = 0;
1201                         hrtimer_cancel(&op->thrtimer);
1202                         bcm_rx_thr_flush(op, 1);
1203                 }
1204 
1205                 if ((op->flags & STARTTIMER) && op->kt_ival1)
1206                         hrtimer_start(&op->timer, op->kt_ival1,
1207                                       HRTIMER_MODE_REL);
1208         }
1209 
1210         /* now we can register for can_ids, if we added a new bcm_op */
1211         if (do_rx_register) {
1212                 if (ifindex) {
1213                         struct net_device *dev;
1214 
1215                         dev = dev_get_by_index(sock_net(sk), ifindex);
1216                         if (dev) {
1217                                 err = can_rx_register(sock_net(sk), dev,
1218                                                       op->can_id,
1219                                                       REGMASK(op->can_id),
1220                                                       bcm_rx_handler, op,
1221                                                       "bcm", sk);
1222 
1223                                 op->rx_reg_dev = dev;
1224                                 dev_put(dev);
1225                         }
1226 
1227                 } else
1228                         err = can_rx_register(sock_net(sk), NULL, op->can_id,
1229                                               REGMASK(op->can_id),
1230                                               bcm_rx_handler, op, "bcm", sk);
1231                 if (err) {
1232                         /* this bcm rx op is broken -> remove it */
1233                         list_del(&op->list);
1234                         bcm_remove_op(op);
1235                         return err;
1236                 }
1237         }
1238 
1239         return msg_head->nframes * op->cfsiz + MHSIZ;
1240 }
1241 
1242 /*
1243  * bcm_tx_send - send a single CAN frame to the CAN interface (for bcm_sendmsg)
1244  */
1245 static int bcm_tx_send(struct msghdr *msg, int ifindex, struct sock *sk,
1246                        int cfsiz)
1247 {
1248         struct sk_buff *skb;
1249         struct net_device *dev;
1250         int err;
1251 
1252         /* we need a real device to send frames */
1253         if (!ifindex)
1254                 return -ENODEV;
1255 
1256         skb = alloc_skb(cfsiz + sizeof(struct can_skb_priv), GFP_KERNEL);
1257         if (!skb)
1258                 return -ENOMEM;
1259 
1260         can_skb_reserve(skb);
1261 
1262         err = memcpy_from_msg(skb_put(skb, cfsiz), msg, cfsiz);
1263         if (err < 0) {
1264                 kfree_skb(skb);
1265                 return err;
1266         }
1267 
1268         dev = dev_get_by_index(sock_net(sk), ifindex);
1269         if (!dev) {
1270                 kfree_skb(skb);
1271                 return -ENODEV;
1272         }
1273 
1274         can_skb_prv(skb)->ifindex = dev->ifindex;
1275         can_skb_prv(skb)->skbcnt = 0;
1276         skb->dev = dev;
1277         can_skb_set_owner(skb, sk);
1278         err = can_send(skb, 1); /* send with loopback */
1279         dev_put(dev);
1280 
1281         if (err)
1282                 return err;
1283 
1284         return cfsiz + MHSIZ;
1285 }
1286 
1287 /*
1288  * bcm_sendmsg - process BCM commands (opcodes) from the userspace
1289  */
1290 static int bcm_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
1291 {
1292         struct sock *sk = sock->sk;
1293         struct bcm_sock *bo = bcm_sk(sk);
1294         int ifindex = bo->ifindex; /* default ifindex for this bcm_op */
1295         struct bcm_msg_head msg_head;
1296         int cfsiz;
1297         int ret; /* read bytes or error codes as return value */
1298 
1299         if (!bo->bound)
1300                 return -ENOTCONN;
1301 
1302         /* check for valid message length from userspace */
1303         if (size < MHSIZ)
1304                 return -EINVAL;
1305 
1306         /* read message head information */
1307         ret = memcpy_from_msg((u8 *)&msg_head, msg, MHSIZ);
1308         if (ret < 0)
1309                 return ret;
1310 
1311         cfsiz = CFSIZ(msg_head.flags);
1312         if ((size - MHSIZ) % cfsiz)
1313                 return -EINVAL;
1314 
1315         /* check for alternative ifindex for this bcm_op */
1316 
1317         if (!ifindex && msg->msg_name) {
1318                 /* no bound device as default => check msg_name */
1319                 DECLARE_SOCKADDR(struct sockaddr_can *, addr, msg->msg_name);
1320 
1321                 if (msg->msg_namelen < sizeof(*addr))
1322                         return -EINVAL;
1323 
1324                 if (addr->can_family != AF_CAN)
1325                         return -EINVAL;
1326 
1327                 /* ifindex from sendto() */
1328                 ifindex = addr->can_ifindex;
1329 
1330                 if (ifindex) {
1331                         struct net_device *dev;
1332 
1333                         dev = dev_get_by_index(sock_net(sk), ifindex);
1334                         if (!dev)
1335                                 return -ENODEV;
1336 
1337                         if (dev->type != ARPHRD_CAN) {
1338                                 dev_put(dev);
1339                                 return -ENODEV;
1340                         }
1341 
1342                         dev_put(dev);
1343                 }
1344         }
1345 
1346         lock_sock(sk);
1347 
1348         switch (msg_head.opcode) {
1349 
1350         case TX_SETUP:
1351                 ret = bcm_tx_setup(&msg_head, msg, ifindex, sk);
1352                 break;
1353 
1354         case RX_SETUP:
1355                 ret = bcm_rx_setup(&msg_head, msg, ifindex, sk);
1356                 break;
1357 
1358         case TX_DELETE:
1359                 if (bcm_delete_tx_op(&bo->tx_ops, &msg_head, ifindex))
1360                         ret = MHSIZ;
1361                 else
1362                         ret = -EINVAL;
1363                 break;
1364 
1365         case RX_DELETE:
1366                 if (bcm_delete_rx_op(&bo->rx_ops, &msg_head, ifindex))
1367                         ret = MHSIZ;
1368                 else
1369                         ret = -EINVAL;
1370                 break;
1371 
1372         case TX_READ:
1373                 /* reuse msg_head for the reply to TX_READ */
1374                 msg_head.opcode  = TX_STATUS;
1375                 ret = bcm_read_op(&bo->tx_ops, &msg_head, ifindex);
1376                 break;
1377 
1378         case RX_READ:
1379                 /* reuse msg_head for the reply to RX_READ */
1380                 msg_head.opcode  = RX_STATUS;
1381                 ret = bcm_read_op(&bo->rx_ops, &msg_head, ifindex);
1382                 break;
1383 
1384         case TX_SEND:
1385                 /* we need exactly one CAN frame behind the msg head */
1386                 if ((msg_head.nframes != 1) || (size != cfsiz + MHSIZ))
1387                         ret = -EINVAL;
1388                 else
1389                         ret = bcm_tx_send(msg, ifindex, sk, cfsiz);
1390                 break;
1391 
1392         default:
1393                 ret = -EINVAL;
1394                 break;
1395         }
1396 
1397         release_sock(sk);
1398 
1399         return ret;
1400 }
1401 
1402 /*
1403  * notification handler for netdevice status changes
1404  */
1405 static int bcm_notifier(struct notifier_block *nb, unsigned long msg,
1406                         void *ptr)
1407 {
1408         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1409         struct bcm_sock *bo = container_of(nb, struct bcm_sock, notifier);
1410         struct sock *sk = &bo->sk;
1411         struct bcm_op *op;
1412         int notify_enodev = 0;
1413 
1414         if (!net_eq(dev_net(dev), sock_net(sk)))
1415                 return NOTIFY_DONE;
1416 
1417         if (dev->type != ARPHRD_CAN)
1418                 return NOTIFY_DONE;
1419 
1420         switch (msg) {
1421 
1422         case NETDEV_UNREGISTER:
1423                 lock_sock(sk);
1424 
1425                 /* remove device specific receive entries */
1426                 list_for_each_entry(op, &bo->rx_ops, list)
1427                         if (op->rx_reg_dev == dev)
1428                                 bcm_rx_unreg(dev, op);
1429 
1430                 /* remove device reference, if this is our bound device */
1431                 if (bo->bound && bo->ifindex == dev->ifindex) {
1432                         bo->bound   = 0;
1433                         bo->ifindex = 0;
1434                         notify_enodev = 1;
1435                 }
1436 
1437                 release_sock(sk);
1438 
1439                 if (notify_enodev) {
1440                         sk->sk_err = ENODEV;
1441                         if (!sock_flag(sk, SOCK_DEAD))
1442                                 sk->sk_error_report(sk);
1443                 }
1444                 break;
1445 
1446         case NETDEV_DOWN:
1447                 if (bo->bound && bo->ifindex == dev->ifindex) {
1448                         sk->sk_err = ENETDOWN;
1449                         if (!sock_flag(sk, SOCK_DEAD))
1450                                 sk->sk_error_report(sk);
1451                 }
1452         }
1453 
1454         return NOTIFY_DONE;
1455 }
1456 
1457 /*
1458  * initial settings for all BCM sockets to be set at socket creation time
1459  */
1460 static int bcm_init(struct sock *sk)
1461 {
1462         struct bcm_sock *bo = bcm_sk(sk);
1463 
1464         bo->bound            = 0;
1465         bo->ifindex          = 0;
1466         bo->dropped_usr_msgs = 0;
1467         bo->bcm_proc_read    = NULL;
1468 
1469         INIT_LIST_HEAD(&bo->tx_ops);
1470         INIT_LIST_HEAD(&bo->rx_ops);
1471 
1472         /* set notifier */
1473         bo->notifier.notifier_call = bcm_notifier;
1474 
1475         register_netdevice_notifier(&bo->notifier);
1476 
1477         return 0;
1478 }
1479 
1480 /*
1481  * standard socket functions
1482  */
1483 static int bcm_release(struct socket *sock)
1484 {
1485         struct sock *sk = sock->sk;
1486         struct net *net;
1487         struct bcm_sock *bo;
1488         struct bcm_op *op, *next;
1489 
1490         if (!sk)
1491                 return 0;
1492 
1493         net = sock_net(sk);
1494         bo = bcm_sk(sk);
1495 
1496         /* remove bcm_ops, timer, rx_unregister(), etc. */
1497 
1498         unregister_netdevice_notifier(&bo->notifier);
1499 
1500         lock_sock(sk);
1501 
1502         list_for_each_entry_safe(op, next, &bo->tx_ops, list)
1503                 bcm_remove_op(op);
1504 
1505         list_for_each_entry_safe(op, next, &bo->rx_ops, list) {
1506                 /*
1507                  * Don't care if we're bound or not (due to netdev problems)
1508                  * can_rx_unregister() is always a save thing to do here.
1509                  */
1510                 if (op->ifindex) {
1511                         /*
1512                          * Only remove subscriptions that had not
1513                          * been removed due to NETDEV_UNREGISTER
1514                          * in bcm_notifier()
1515                          */
1516                         if (op->rx_reg_dev) {
1517                                 struct net_device *dev;
1518 
1519                                 dev = dev_get_by_index(net, op->ifindex);
1520                                 if (dev) {
1521                                         bcm_rx_unreg(dev, op);
1522                                         dev_put(dev);
1523                                 }
1524                         }
1525                 } else
1526                         can_rx_unregister(net, NULL, op->can_id,
1527                                           REGMASK(op->can_id),
1528                                           bcm_rx_handler, op);
1529 
1530                 bcm_remove_op(op);
1531         }
1532 
1533 #if IS_ENABLED(CONFIG_PROC_FS)
1534         /* remove procfs entry */
1535         if (net->can.bcmproc_dir && bo->bcm_proc_read)
1536                 remove_proc_entry(bo->procname, net->can.bcmproc_dir);
1537 #endif /* CONFIG_PROC_FS */
1538 
1539         /* remove device reference */
1540         if (bo->bound) {
1541                 bo->bound   = 0;
1542                 bo->ifindex = 0;
1543         }
1544 
1545         sock_orphan(sk);
1546         sock->sk = NULL;
1547 
1548         release_sock(sk);
1549         sock_put(sk);
1550 
1551         return 0;
1552 }
1553 
1554 static int bcm_connect(struct socket *sock, struct sockaddr *uaddr, int len,
1555                        int flags)
1556 {
1557         struct sockaddr_can *addr = (struct sockaddr_can *)uaddr;
1558         struct sock *sk = sock->sk;
1559         struct bcm_sock *bo = bcm_sk(sk);
1560         struct net *net = sock_net(sk);
1561         int ret = 0;
1562 
1563         if (len < sizeof(*addr))
1564                 return -EINVAL;
1565 
1566         lock_sock(sk);
1567 
1568         if (bo->bound) {
1569                 ret = -EISCONN;
1570                 goto fail;
1571         }
1572 
1573         /* bind a device to this socket */
1574         if (addr->can_ifindex) {
1575                 struct net_device *dev;
1576 
1577                 dev = dev_get_by_index(net, addr->can_ifindex);
1578                 if (!dev) {
1579                         ret = -ENODEV;
1580                         goto fail;
1581                 }
1582                 if (dev->type != ARPHRD_CAN) {
1583                         dev_put(dev);
1584                         ret = -ENODEV;
1585                         goto fail;
1586                 }
1587 
1588                 bo->ifindex = dev->ifindex;
1589                 dev_put(dev);
1590 
1591         } else {
1592                 /* no interface reference for ifindex = 0 ('any' CAN device) */
1593                 bo->ifindex = 0;
1594         }
1595 
1596 #if IS_ENABLED(CONFIG_PROC_FS)
1597         if (net->can.bcmproc_dir) {
1598                 /* unique socket address as filename */
1599                 sprintf(bo->procname, "%lu", sock_i_ino(sk));
1600                 bo->bcm_proc_read = proc_create_net_single(bo->procname, 0644,
1601                                                      net->can.bcmproc_dir,
1602                                                      bcm_proc_show, sk);
1603                 if (!bo->bcm_proc_read) {
1604                         ret = -ENOMEM;
1605                         goto fail;
1606                 }
1607         }
1608 #endif /* CONFIG_PROC_FS */
1609 
1610         bo->bound = 1;
1611 
1612 fail:
1613         release_sock(sk);
1614 
1615         return ret;
1616 }
1617 
1618 static int bcm_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
1619                        int flags)
1620 {
1621         struct sock *sk = sock->sk;
1622         struct sk_buff *skb;
1623         int error = 0;
1624         int noblock;
1625         int err;
1626 
1627         noblock =  flags & MSG_DONTWAIT;
1628         flags   &= ~MSG_DONTWAIT;
1629         skb = skb_recv_datagram(sk, flags, noblock, &error);
1630         if (!skb)
1631                 return error;
1632 
1633         if (skb->len < size)
1634                 size = skb->len;
1635 
1636         err = memcpy_to_msg(msg, skb->data, size);
1637         if (err < 0) {
1638                 skb_free_datagram(sk, skb);
1639                 return err;
1640         }
1641 
1642         sock_recv_ts_and_drops(msg, sk, skb);
1643 
1644         if (msg->msg_name) {
1645                 __sockaddr_check_size(sizeof(struct sockaddr_can));
1646                 msg->msg_namelen = sizeof(struct sockaddr_can);
1647                 memcpy(msg->msg_name, skb->cb, msg->msg_namelen);
1648         }
1649 
1650         skb_free_datagram(sk, skb);
1651 
1652         return size;
1653 }
1654 
1655 static const struct proto_ops bcm_ops = {
1656         .family        = PF_CAN,
1657         .release       = bcm_release,
1658         .bind          = sock_no_bind,
1659         .connect       = bcm_connect,
1660         .socketpair    = sock_no_socketpair,
1661         .accept        = sock_no_accept,
1662         .getname       = sock_no_getname,
1663         .poll          = datagram_poll,
1664         .ioctl         = can_ioctl,     /* use can_ioctl() from af_can.c */
1665         .listen        = sock_no_listen,
1666         .shutdown      = sock_no_shutdown,
1667         .setsockopt    = sock_no_setsockopt,
1668         .getsockopt    = sock_no_getsockopt,
1669         .sendmsg       = bcm_sendmsg,
1670         .recvmsg       = bcm_recvmsg,
1671         .mmap          = sock_no_mmap,
1672         .sendpage      = sock_no_sendpage,
1673 };
1674 
1675 static struct proto bcm_proto __read_mostly = {
1676         .name       = "CAN_BCM",
1677         .owner      = THIS_MODULE,
1678         .obj_size   = sizeof(struct bcm_sock),
1679         .init       = bcm_init,
1680 };
1681 
1682 static const struct can_proto bcm_can_proto = {
1683         .type       = SOCK_DGRAM,
1684         .protocol   = CAN_BCM,
1685         .ops        = &bcm_ops,
1686         .prot       = &bcm_proto,
1687 };
1688 
1689 static int canbcm_pernet_init(struct net *net)
1690 {
1691 #if IS_ENABLED(CONFIG_PROC_FS)
1692         /* create /proc/net/can-bcm directory */
1693         net->can.bcmproc_dir = proc_net_mkdir(net, "can-bcm", net->proc_net);
1694 #endif /* CONFIG_PROC_FS */
1695 
1696         return 0;
1697 }
1698 
1699 static void canbcm_pernet_exit(struct net *net)
1700 {
1701 #if IS_ENABLED(CONFIG_PROC_FS)
1702         /* remove /proc/net/can-bcm directory */
1703         if (net->can.bcmproc_dir)
1704                 remove_proc_entry("can-bcm", net->proc_net);
1705 #endif /* CONFIG_PROC_FS */
1706 }
1707 
1708 static struct pernet_operations canbcm_pernet_ops __read_mostly = {
1709         .init = canbcm_pernet_init,
1710         .exit = canbcm_pernet_exit,
1711 };
1712 
1713 static int __init bcm_module_init(void)
1714 {
1715         int err;
1716 
1717         pr_info("can: broadcast manager protocol (rev " CAN_BCM_VERSION " t)\n");
1718 
1719         err = can_proto_register(&bcm_can_proto);
1720         if (err < 0) {
1721                 printk(KERN_ERR "can: registration of bcm protocol failed\n");
1722                 return err;
1723         }
1724 
1725         register_pernet_subsys(&canbcm_pernet_ops);
1726         return 0;
1727 }
1728 
1729 static void __exit bcm_module_exit(void)
1730 {
1731         can_proto_unregister(&bcm_can_proto);
1732         unregister_pernet_subsys(&canbcm_pernet_ops);
1733 }
1734 
1735 module_init(bcm_module_init);
1736 module_exit(bcm_module_exit);
1737 

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