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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) 2002-2016 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 "20161123"
 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 static struct proc_dir_entry *proc_dir;
122 
123 struct bcm_sock {
124         struct sock sk;
125         int bound;
126         int ifindex;
127         struct notifier_block notifier;
128         struct list_head rx_ops;
129         struct list_head tx_ops;
130         unsigned long dropped_usr_msgs;
131         struct proc_dir_entry *bcm_proc_read;
132         char procname [32]; /* inode number in decimal with \0 */
133 };
134 
135 static inline struct bcm_sock *bcm_sk(const struct sock *sk)
136 {
137         return (struct bcm_sock *)sk;
138 }
139 
140 static inline ktime_t bcm_timeval_to_ktime(struct bcm_timeval tv)
141 {
142         return ktime_set(tv.tv_sec, tv.tv_usec * NSEC_PER_USEC);
143 }
144 
145 #define CFSIZ(flags) ((flags & CAN_FD_FRAME) ? CANFD_MTU : CAN_MTU)
146 #define OPSIZ sizeof(struct bcm_op)
147 #define MHSIZ sizeof(struct bcm_msg_head)
148 
149 /*
150  * procfs functions
151  */
152 static char *bcm_proc_getifname(char *result, int ifindex)
153 {
154         struct net_device *dev;
155 
156         if (!ifindex)
157                 return "any";
158 
159         rcu_read_lock();
160         dev = dev_get_by_index_rcu(&init_net, ifindex);
161         if (dev)
162                 strcpy(result, dev->name);
163         else
164                 strcpy(result, "???");
165         rcu_read_unlock();
166 
167         return result;
168 }
169 
170 static int bcm_proc_show(struct seq_file *m, void *v)
171 {
172         char ifname[IFNAMSIZ];
173         struct sock *sk = (struct sock *)m->private;
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(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(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(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 
243 static int bcm_proc_open(struct inode *inode, struct file *file)
244 {
245         return single_open(file, bcm_proc_show, PDE_DATA(inode));
246 }
247 
248 static const struct file_operations bcm_proc_fops = {
249         .owner          = THIS_MODULE,
250         .open           = bcm_proc_open,
251         .read           = seq_read,
252         .llseek         = seq_lseek,
253         .release        = single_release,
254 };
255 
256 /*
257  * bcm_can_tx - send the (next) CAN frame to the appropriate CAN interface
258  *              of the given bcm tx op
259  */
260 static void bcm_can_tx(struct bcm_op *op)
261 {
262         struct sk_buff *skb;
263         struct net_device *dev;
264         struct canfd_frame *cf = op->frames + op->cfsiz * op->currframe;
265 
266         /* no target device? => exit */
267         if (!op->ifindex)
268                 return;
269 
270         dev = dev_get_by_index(&init_net, op->ifindex);
271         if (!dev) {
272                 /* RFC: should this bcm_op remove itself here? */
273                 return;
274         }
275 
276         skb = alloc_skb(op->cfsiz + sizeof(struct can_skb_priv), gfp_any());
277         if (!skb)
278                 goto out;
279 
280         can_skb_reserve(skb);
281         can_skb_prv(skb)->ifindex = dev->ifindex;
282         can_skb_prv(skb)->skbcnt = 0;
283 
284         memcpy(skb_put(skb, op->cfsiz), cf, op->cfsiz);
285 
286         /* send with loopback */
287         skb->dev = dev;
288         can_skb_set_owner(skb, op->sk);
289         can_send(skb, 1);
290 
291         /* update statistics */
292         op->currframe++;
293         op->frames_abs++;
294 
295         /* reached last frame? */
296         if (op->currframe >= op->nframes)
297                 op->currframe = 0;
298 out:
299         dev_put(dev);
300 }
301 
302 /*
303  * bcm_send_to_user - send a BCM message to the userspace
304  *                    (consisting of bcm_msg_head + x CAN frames)
305  */
306 static void bcm_send_to_user(struct bcm_op *op, struct bcm_msg_head *head,
307                              struct canfd_frame *frames, int has_timestamp)
308 {
309         struct sk_buff *skb;
310         struct canfd_frame *firstframe;
311         struct sockaddr_can *addr;
312         struct sock *sk = op->sk;
313         unsigned int datalen = head->nframes * op->cfsiz;
314         int err;
315 
316         skb = alloc_skb(sizeof(*head) + datalen, gfp_any());
317         if (!skb)
318                 return;
319 
320         memcpy(skb_put(skb, sizeof(*head)), head, sizeof(*head));
321 
322         if (head->nframes) {
323                 /* CAN frames starting here */
324                 firstframe = (struct canfd_frame *)skb_tail_pointer(skb);
325 
326                 memcpy(skb_put(skb, datalen), frames, datalen);
327 
328                 /*
329                  * the BCM uses the flags-element of the canfd_frame
330                  * structure for internal purposes. This is only
331                  * relevant for updates that are generated by the
332                  * BCM, where nframes is 1
333                  */
334                 if (head->nframes == 1)
335                         firstframe->flags &= BCM_CAN_FLAGS_MASK;
336         }
337 
338         if (has_timestamp) {
339                 /* restore rx timestamp */
340                 skb->tstamp = op->rx_stamp;
341         }
342 
343         /*
344          *  Put the datagram to the queue so that bcm_recvmsg() can
345          *  get it from there.  We need to pass the interface index to
346          *  bcm_recvmsg().  We pass a whole struct sockaddr_can in skb->cb
347          *  containing the interface index.
348          */
349 
350         sock_skb_cb_check_size(sizeof(struct sockaddr_can));
351         addr = (struct sockaddr_can *)skb->cb;
352         memset(addr, 0, sizeof(*addr));
353         addr->can_family  = AF_CAN;
354         addr->can_ifindex = op->rx_ifindex;
355 
356         err = sock_queue_rcv_skb(sk, skb);
357         if (err < 0) {
358                 struct bcm_sock *bo = bcm_sk(sk);
359 
360                 kfree_skb(skb);
361                 /* don't care about overflows in this statistic */
362                 bo->dropped_usr_msgs++;
363         }
364 }
365 
366 static void bcm_tx_start_timer(struct bcm_op *op)
367 {
368         if (op->kt_ival1 && op->count)
369                 hrtimer_start(&op->timer,
370                               ktime_add(ktime_get(), op->kt_ival1),
371                               HRTIMER_MODE_ABS);
372         else if (op->kt_ival2)
373                 hrtimer_start(&op->timer,
374                               ktime_add(ktime_get(), op->kt_ival2),
375                               HRTIMER_MODE_ABS);
376 }
377 
378 static void bcm_tx_timeout_tsklet(unsigned long data)
379 {
380         struct bcm_op *op = (struct bcm_op *)data;
381         struct bcm_msg_head msg_head;
382 
383         if (op->kt_ival1 && (op->count > 0)) {
384 
385                 op->count--;
386                 if (!op->count && (op->flags & TX_COUNTEVT)) {
387 
388                         /* create notification to user */
389                         msg_head.opcode  = TX_EXPIRED;
390                         msg_head.flags   = op->flags;
391                         msg_head.count   = op->count;
392                         msg_head.ival1   = op->ival1;
393                         msg_head.ival2   = op->ival2;
394                         msg_head.can_id  = op->can_id;
395                         msg_head.nframes = 0;
396 
397                         bcm_send_to_user(op, &msg_head, NULL, 0);
398                 }
399                 bcm_can_tx(op);
400 
401         } else if (op->kt_ival2)
402                 bcm_can_tx(op);
403 
404         bcm_tx_start_timer(op);
405 }
406 
407 /*
408  * bcm_tx_timeout_handler - performs cyclic CAN frame transmissions
409  */
410 static enum hrtimer_restart bcm_tx_timeout_handler(struct hrtimer *hrtimer)
411 {
412         struct bcm_op *op = container_of(hrtimer, struct bcm_op, timer);
413 
414         tasklet_schedule(&op->tsklet);
415 
416         return HRTIMER_NORESTART;
417 }
418 
419 /*
420  * bcm_rx_changed - create a RX_CHANGED notification due to changed content
421  */
422 static void bcm_rx_changed(struct bcm_op *op, struct canfd_frame *data)
423 {
424         struct bcm_msg_head head;
425 
426         /* update statistics */
427         op->frames_filtered++;
428 
429         /* prevent statistics overflow */
430         if (op->frames_filtered > ULONG_MAX/100)
431                 op->frames_filtered = op->frames_abs = 0;
432 
433         /* this element is not throttled anymore */
434         data->flags &= (BCM_CAN_FLAGS_MASK|RX_RECV);
435 
436         head.opcode  = RX_CHANGED;
437         head.flags   = op->flags;
438         head.count   = op->count;
439         head.ival1   = op->ival1;
440         head.ival2   = op->ival2;
441         head.can_id  = op->can_id;
442         head.nframes = 1;
443 
444         bcm_send_to_user(op, &head, data, 1);
445 }
446 
447 /*
448  * bcm_rx_update_and_send - process a detected relevant receive content change
449  *                          1. update the last received data
450  *                          2. send a notification to the user (if possible)
451  */
452 static void bcm_rx_update_and_send(struct bcm_op *op,
453                                    struct canfd_frame *lastdata,
454                                    const struct canfd_frame *rxdata)
455 {
456         memcpy(lastdata, rxdata, op->cfsiz);
457 
458         /* mark as used and throttled by default */
459         lastdata->flags |= (RX_RECV|RX_THR);
460 
461         /* throttling mode inactive ? */
462         if (!op->kt_ival2) {
463                 /* send RX_CHANGED to the user immediately */
464                 bcm_rx_changed(op, lastdata);
465                 return;
466         }
467 
468         /* with active throttling timer we are just done here */
469         if (hrtimer_active(&op->thrtimer))
470                 return;
471 
472         /* first reception with enabled throttling mode */
473         if (!op->kt_lastmsg)
474                 goto rx_changed_settime;
475 
476         /* got a second frame inside a potential throttle period? */
477         if (ktime_us_delta(ktime_get(), op->kt_lastmsg) <
478             ktime_to_us(op->kt_ival2)) {
479                 /* do not send the saved data - only start throttle timer */
480                 hrtimer_start(&op->thrtimer,
481                               ktime_add(op->kt_lastmsg, op->kt_ival2),
482                               HRTIMER_MODE_ABS);
483                 return;
484         }
485 
486         /* the gap was that big, that throttling was not needed here */
487 rx_changed_settime:
488         bcm_rx_changed(op, lastdata);
489         op->kt_lastmsg = ktime_get();
490 }
491 
492 /*
493  * bcm_rx_cmp_to_index - (bit)compares the currently received data to formerly
494  *                       received data stored in op->last_frames[]
495  */
496 static void bcm_rx_cmp_to_index(struct bcm_op *op, unsigned int index,
497                                 const struct canfd_frame *rxdata)
498 {
499         struct canfd_frame *cf = op->frames + op->cfsiz * index;
500         struct canfd_frame *lcf = op->last_frames + op->cfsiz * index;
501         int i;
502 
503         /*
504          * no one uses the MSBs of flags for comparison,
505          * so we use it here to detect the first time of reception
506          */
507 
508         if (!(lcf->flags & RX_RECV)) {
509                 /* received data for the first time => send update to user */
510                 bcm_rx_update_and_send(op, lcf, rxdata);
511                 return;
512         }
513 
514         /* do a real check in CAN frame data section */
515         for (i = 0; i < rxdata->len; i += 8) {
516                 if ((get_u64(cf, i) & get_u64(rxdata, i)) !=
517                     (get_u64(cf, i) & get_u64(lcf, i))) {
518                         bcm_rx_update_and_send(op, lcf, rxdata);
519                         return;
520                 }
521         }
522 
523         if (op->flags & RX_CHECK_DLC) {
524                 /* do a real check in CAN frame length */
525                 if (rxdata->len != lcf->len) {
526                         bcm_rx_update_and_send(op, lcf, rxdata);
527                         return;
528                 }
529         }
530 }
531 
532 /*
533  * bcm_rx_starttimer - enable timeout monitoring for CAN frame reception
534  */
535 static void bcm_rx_starttimer(struct bcm_op *op)
536 {
537         if (op->flags & RX_NO_AUTOTIMER)
538                 return;
539 
540         if (op->kt_ival1)
541                 hrtimer_start(&op->timer, op->kt_ival1, HRTIMER_MODE_REL);
542 }
543 
544 static void bcm_rx_timeout_tsklet(unsigned long data)
545 {
546         struct bcm_op *op = (struct bcm_op *)data;
547         struct bcm_msg_head msg_head;
548 
549         /* create notification to user */
550         msg_head.opcode  = RX_TIMEOUT;
551         msg_head.flags   = op->flags;
552         msg_head.count   = op->count;
553         msg_head.ival1   = op->ival1;
554         msg_head.ival2   = op->ival2;
555         msg_head.can_id  = op->can_id;
556         msg_head.nframes = 0;
557 
558         bcm_send_to_user(op, &msg_head, NULL, 0);
559 }
560 
561 /*
562  * bcm_rx_timeout_handler - when the (cyclic) CAN frame reception timed out
563  */
564 static enum hrtimer_restart bcm_rx_timeout_handler(struct hrtimer *hrtimer)
565 {
566         struct bcm_op *op = container_of(hrtimer, struct bcm_op, timer);
567 
568         /* schedule before NET_RX_SOFTIRQ */
569         tasklet_hi_schedule(&op->tsklet);
570 
571         /* no restart of the timer is done here! */
572 
573         /* if user wants to be informed, when cyclic CAN-Messages come back */
574         if ((op->flags & RX_ANNOUNCE_RESUME) && op->last_frames) {
575                 /* clear received CAN frames to indicate 'nothing received' */
576                 memset(op->last_frames, 0, op->nframes * op->cfsiz);
577         }
578 
579         return HRTIMER_NORESTART;
580 }
581 
582 /*
583  * bcm_rx_do_flush - helper for bcm_rx_thr_flush
584  */
585 static inline int bcm_rx_do_flush(struct bcm_op *op, int update,
586                                   unsigned int index)
587 {
588         struct canfd_frame *lcf = op->last_frames + op->cfsiz * index;
589 
590         if ((op->last_frames) && (lcf->flags & RX_THR)) {
591                 if (update)
592                         bcm_rx_changed(op, lcf);
593                 return 1;
594         }
595         return 0;
596 }
597 
598 /*
599  * bcm_rx_thr_flush - Check for throttled data and send it to the userspace
600  *
601  * update == 0 : just check if throttled data is available  (any irq context)
602  * update == 1 : check and send throttled data to userspace (soft_irq context)
603  */
604 static int bcm_rx_thr_flush(struct bcm_op *op, int update)
605 {
606         int updated = 0;
607 
608         if (op->nframes > 1) {
609                 unsigned int i;
610 
611                 /* for MUX filter we start at index 1 */
612                 for (i = 1; i < op->nframes; i++)
613                         updated += bcm_rx_do_flush(op, update, i);
614 
615         } else {
616                 /* for RX_FILTER_ID and simple filter */
617                 updated += bcm_rx_do_flush(op, update, 0);
618         }
619 
620         return updated;
621 }
622 
623 static void bcm_rx_thr_tsklet(unsigned long data)
624 {
625         struct bcm_op *op = (struct bcm_op *)data;
626 
627         /* push the changed data to the userspace */
628         bcm_rx_thr_flush(op, 1);
629 }
630 
631 /*
632  * bcm_rx_thr_handler - the time for blocked content updates is over now:
633  *                      Check for throttled data and send it to the userspace
634  */
635 static enum hrtimer_restart bcm_rx_thr_handler(struct hrtimer *hrtimer)
636 {
637         struct bcm_op *op = container_of(hrtimer, struct bcm_op, thrtimer);
638 
639         tasklet_schedule(&op->thrtsklet);
640 
641         if (bcm_rx_thr_flush(op, 0)) {
642                 hrtimer_forward(hrtimer, ktime_get(), op->kt_ival2);
643                 return HRTIMER_RESTART;
644         } else {
645                 /* rearm throttle handling */
646                 op->kt_lastmsg = 0;
647                 return HRTIMER_NORESTART;
648         }
649 }
650 
651 /*
652  * bcm_rx_handler - handle a CAN frame reception
653  */
654 static void bcm_rx_handler(struct sk_buff *skb, void *data)
655 {
656         struct bcm_op *op = (struct bcm_op *)data;
657         const struct canfd_frame *rxframe = (struct canfd_frame *)skb->data;
658         unsigned int i;
659 
660         if (op->can_id != rxframe->can_id)
661                 return;
662 
663         /* make sure to handle the correct frame type (CAN / CAN FD) */
664         if (skb->len != op->cfsiz)
665                 return;
666 
667         /* disable timeout */
668         hrtimer_cancel(&op->timer);
669 
670         /* save rx timestamp */
671         op->rx_stamp = skb->tstamp;
672         /* save originator for recvfrom() */
673         op->rx_ifindex = skb->dev->ifindex;
674         /* update statistics */
675         op->frames_abs++;
676 
677         if (op->flags & RX_RTR_FRAME) {
678                 /* send reply for RTR-request (placed in op->frames[0]) */
679                 bcm_can_tx(op);
680                 return;
681         }
682 
683         if (op->flags & RX_FILTER_ID) {
684                 /* the easiest case */
685                 bcm_rx_update_and_send(op, op->last_frames, rxframe);
686                 goto rx_starttimer;
687         }
688 
689         if (op->nframes == 1) {
690                 /* simple compare with index 0 */
691                 bcm_rx_cmp_to_index(op, 0, rxframe);
692                 goto rx_starttimer;
693         }
694 
695         if (op->nframes > 1) {
696                 /*
697                  * multiplex compare
698                  *
699                  * find the first multiplex mask that fits.
700                  * Remark: The MUX-mask is stored in index 0 - but only the
701                  * first 64 bits of the frame data[] are relevant (CAN FD)
702                  */
703 
704                 for (i = 1; i < op->nframes; i++) {
705                         if ((get_u64(op->frames, 0) & get_u64(rxframe, 0)) ==
706                             (get_u64(op->frames, 0) &
707                              get_u64(op->frames + op->cfsiz * i, 0))) {
708                                 bcm_rx_cmp_to_index(op, i, rxframe);
709                                 break;
710                         }
711                 }
712         }
713 
714 rx_starttimer:
715         bcm_rx_starttimer(op);
716 }
717 
718 /*
719  * helpers for bcm_op handling: find & delete bcm [rx|tx] op elements
720  */
721 static struct bcm_op *bcm_find_op(struct list_head *ops,
722                                   struct bcm_msg_head *mh, int ifindex)
723 {
724         struct bcm_op *op;
725 
726         list_for_each_entry(op, ops, list) {
727                 if ((op->can_id == mh->can_id) && (op->ifindex == ifindex) &&
728                     (op->flags & CAN_FD_FRAME) == (mh->flags & CAN_FD_FRAME))
729                         return op;
730         }
731 
732         return NULL;
733 }
734 
735 static void bcm_remove_op(struct bcm_op *op)
736 {
737         if (op->tsklet.func) {
738                 while (test_bit(TASKLET_STATE_SCHED, &op->tsklet.state) ||
739                        test_bit(TASKLET_STATE_RUN, &op->tsklet.state) ||
740                        hrtimer_active(&op->timer)) {
741                         hrtimer_cancel(&op->timer);
742                         tasklet_kill(&op->tsklet);
743                 }
744         }
745 
746         if (op->thrtsklet.func) {
747                 while (test_bit(TASKLET_STATE_SCHED, &op->thrtsklet.state) ||
748                        test_bit(TASKLET_STATE_RUN, &op->thrtsklet.state) ||
749                        hrtimer_active(&op->thrtimer)) {
750                         hrtimer_cancel(&op->thrtimer);
751                         tasklet_kill(&op->thrtsklet);
752                 }
753         }
754 
755         if ((op->frames) && (op->frames != &op->sframe))
756                 kfree(op->frames);
757 
758         if ((op->last_frames) && (op->last_frames != &op->last_sframe))
759                 kfree(op->last_frames);
760 
761         kfree(op);
762 }
763 
764 static void bcm_rx_unreg(struct net_device *dev, struct bcm_op *op)
765 {
766         if (op->rx_reg_dev == dev) {
767                 can_rx_unregister(dev, op->can_id, REGMASK(op->can_id),
768                                   bcm_rx_handler, op);
769 
770                 /* mark as removed subscription */
771                 op->rx_reg_dev = NULL;
772         } else
773                 printk(KERN_ERR "can-bcm: bcm_rx_unreg: registered device "
774                        "mismatch %p %p\n", op->rx_reg_dev, dev);
775 }
776 
777 /*
778  * bcm_delete_rx_op - find and remove a rx op (returns number of removed ops)
779  */
780 static int bcm_delete_rx_op(struct list_head *ops, struct bcm_msg_head *mh,
781                             int ifindex)
782 {
783         struct bcm_op *op, *n;
784 
785         list_for_each_entry_safe(op, n, ops, list) {
786                 if ((op->can_id == mh->can_id) && (op->ifindex == ifindex) &&
787                     (op->flags & CAN_FD_FRAME) == (mh->flags & CAN_FD_FRAME)) {
788 
789                         /*
790                          * Don't care if we're bound or not (due to netdev
791                          * problems) can_rx_unregister() is always a save
792                          * thing to do here.
793                          */
794                         if (op->ifindex) {
795                                 /*
796                                  * Only remove subscriptions that had not
797                                  * been removed due to NETDEV_UNREGISTER
798                                  * in bcm_notifier()
799                                  */
800                                 if (op->rx_reg_dev) {
801                                         struct net_device *dev;
802 
803                                         dev = dev_get_by_index(&init_net,
804                                                                op->ifindex);
805                                         if (dev) {
806                                                 bcm_rx_unreg(dev, op);
807                                                 dev_put(dev);
808                                         }
809                                 }
810                         } else
811                                 can_rx_unregister(NULL, op->can_id,
812                                                   REGMASK(op->can_id),
813                                                   bcm_rx_handler, op);
814 
815                         list_del(&op->list);
816                         bcm_remove_op(op);
817                         return 1; /* done */
818                 }
819         }
820 
821         return 0; /* not found */
822 }
823 
824 /*
825  * bcm_delete_tx_op - find and remove a tx op (returns number of removed ops)
826  */
827 static int bcm_delete_tx_op(struct list_head *ops, struct bcm_msg_head *mh,
828                             int ifindex)
829 {
830         struct bcm_op *op, *n;
831 
832         list_for_each_entry_safe(op, n, ops, list) {
833                 if ((op->can_id == mh->can_id) && (op->ifindex == ifindex) &&
834                     (op->flags & CAN_FD_FRAME) == (mh->flags & CAN_FD_FRAME)) {
835                         list_del(&op->list);
836                         bcm_remove_op(op);
837                         return 1; /* done */
838                 }
839         }
840 
841         return 0; /* not found */
842 }
843 
844 /*
845  * bcm_read_op - read out a bcm_op and send it to the user (for bcm_sendmsg)
846  */
847 static int bcm_read_op(struct list_head *ops, struct bcm_msg_head *msg_head,
848                        int ifindex)
849 {
850         struct bcm_op *op = bcm_find_op(ops, msg_head, ifindex);
851 
852         if (!op)
853                 return -EINVAL;
854 
855         /* put current values into msg_head */
856         msg_head->flags   = op->flags;
857         msg_head->count   = op->count;
858         msg_head->ival1   = op->ival1;
859         msg_head->ival2   = op->ival2;
860         msg_head->nframes = op->nframes;
861 
862         bcm_send_to_user(op, msg_head, op->frames, 0);
863 
864         return MHSIZ;
865 }
866 
867 /*
868  * bcm_tx_setup - create or update a bcm tx op (for bcm_sendmsg)
869  */
870 static int bcm_tx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
871                         int ifindex, struct sock *sk)
872 {
873         struct bcm_sock *bo = bcm_sk(sk);
874         struct bcm_op *op;
875         struct canfd_frame *cf;
876         unsigned int i;
877         int err;
878 
879         /* we need a real device to send frames */
880         if (!ifindex)
881                 return -ENODEV;
882 
883         /* check nframes boundaries - we need at least one CAN frame */
884         if (msg_head->nframes < 1 || msg_head->nframes > MAX_NFRAMES)
885                 return -EINVAL;
886 
887         /* check the given can_id */
888         op = bcm_find_op(&bo->tx_ops, msg_head, ifindex);
889         if (op) {
890                 /* update existing BCM operation */
891 
892                 /*
893                  * Do we need more space for the CAN frames than currently
894                  * allocated? -> This is a _really_ unusual use-case and
895                  * therefore (complexity / locking) it is not supported.
896                  */
897                 if (msg_head->nframes > op->nframes)
898                         return -E2BIG;
899 
900                 /* update CAN frames content */
901                 for (i = 0; i < msg_head->nframes; i++) {
902 
903                         cf = op->frames + op->cfsiz * i;
904                         err = memcpy_from_msg((u8 *)cf, msg, op->cfsiz);
905 
906                         if (op->flags & CAN_FD_FRAME) {
907                                 if (cf->len > 64)
908                                         err = -EINVAL;
909                         } else {
910                                 if (cf->len > 8)
911                                         err = -EINVAL;
912                         }
913 
914                         if (err < 0)
915                                 return err;
916 
917                         if (msg_head->flags & TX_CP_CAN_ID) {
918                                 /* copy can_id into frame */
919                                 cf->can_id = msg_head->can_id;
920                         }
921                 }
922                 op->flags = msg_head->flags;
923 
924         } else {
925                 /* insert new BCM operation for the given can_id */
926 
927                 op = kzalloc(OPSIZ, GFP_KERNEL);
928                 if (!op)
929                         return -ENOMEM;
930 
931                 op->can_id = msg_head->can_id;
932                 op->cfsiz = CFSIZ(msg_head->flags);
933                 op->flags = msg_head->flags;
934 
935                 /* create array for CAN frames and copy the data */
936                 if (msg_head->nframes > 1) {
937                         op->frames = kmalloc(msg_head->nframes * op->cfsiz,
938                                              GFP_KERNEL);
939                         if (!op->frames) {
940                                 kfree(op);
941                                 return -ENOMEM;
942                         }
943                 } else
944                         op->frames = &op->sframe;
945 
946                 for (i = 0; i < msg_head->nframes; i++) {
947 
948                         cf = op->frames + op->cfsiz * i;
949                         err = memcpy_from_msg((u8 *)cf, msg, op->cfsiz);
950 
951                         if (op->flags & CAN_FD_FRAME) {
952                                 if (cf->len > 64)
953                                         err = -EINVAL;
954                         } else {
955                                 if (cf->len > 8)
956                                         err = -EINVAL;
957                         }
958 
959                         if (err < 0) {
960                                 if (op->frames != &op->sframe)
961                                         kfree(op->frames);
962                                 kfree(op);
963                                 return err;
964                         }
965 
966                         if (msg_head->flags & TX_CP_CAN_ID) {
967                                 /* copy can_id into frame */
968                                 cf->can_id = msg_head->can_id;
969                         }
970                 }
971 
972                 /* tx_ops never compare with previous received messages */
973                 op->last_frames = NULL;
974 
975                 /* bcm_can_tx / bcm_tx_timeout_handler needs this */
976                 op->sk = sk;
977                 op->ifindex = ifindex;
978 
979                 /* initialize uninitialized (kzalloc) structure */
980                 hrtimer_init(&op->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
981                 op->timer.function = bcm_tx_timeout_handler;
982 
983                 /* initialize tasklet for tx countevent notification */
984                 tasklet_init(&op->tsklet, bcm_tx_timeout_tsklet,
985                              (unsigned long) op);
986 
987                 /* currently unused in tx_ops */
988                 hrtimer_init(&op->thrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
989 
990                 /* add this bcm_op to the list of the tx_ops */
991                 list_add(&op->list, &bo->tx_ops);
992 
993         } /* if ((op = bcm_find_op(&bo->tx_ops, msg_head->can_id, ifindex))) */
994 
995         if (op->nframes != msg_head->nframes) {
996                 op->nframes   = msg_head->nframes;
997                 /* start multiple frame transmission with index 0 */
998                 op->currframe = 0;
999         }
1000 
1001         /* check flags */
1002 
1003         if (op->flags & TX_RESET_MULTI_IDX) {
1004                 /* start multiple frame transmission with index 0 */
1005                 op->currframe = 0;
1006         }
1007 
1008         if (op->flags & SETTIMER) {
1009                 /* set timer values */
1010                 op->count = msg_head->count;
1011                 op->ival1 = msg_head->ival1;
1012                 op->ival2 = msg_head->ival2;
1013                 op->kt_ival1 = bcm_timeval_to_ktime(msg_head->ival1);
1014                 op->kt_ival2 = bcm_timeval_to_ktime(msg_head->ival2);
1015 
1016                 /* disable an active timer due to zero values? */
1017                 if (!op->kt_ival1 && !op->kt_ival2)
1018                         hrtimer_cancel(&op->timer);
1019         }
1020 
1021         if (op->flags & STARTTIMER) {
1022                 hrtimer_cancel(&op->timer);
1023                 /* spec: send CAN frame when starting timer */
1024                 op->flags |= TX_ANNOUNCE;
1025         }
1026 
1027         if (op->flags & TX_ANNOUNCE) {
1028                 bcm_can_tx(op);
1029                 if (op->count)
1030                         op->count--;
1031         }
1032 
1033         if (op->flags & STARTTIMER)
1034                 bcm_tx_start_timer(op);
1035 
1036         return msg_head->nframes * op->cfsiz + MHSIZ;
1037 }
1038 
1039 /*
1040  * bcm_rx_setup - create or update a bcm rx op (for bcm_sendmsg)
1041  */
1042 static int bcm_rx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
1043                         int ifindex, struct sock *sk)
1044 {
1045         struct bcm_sock *bo = bcm_sk(sk);
1046         struct bcm_op *op;
1047         int do_rx_register;
1048         int err = 0;
1049 
1050         if ((msg_head->flags & RX_FILTER_ID) || (!(msg_head->nframes))) {
1051                 /* be robust against wrong usage ... */
1052                 msg_head->flags |= RX_FILTER_ID;
1053                 /* ignore trailing garbage */
1054                 msg_head->nframes = 0;
1055         }
1056 
1057         /* the first element contains the mux-mask => MAX_NFRAMES + 1  */
1058         if (msg_head->nframes > MAX_NFRAMES + 1)
1059                 return -EINVAL;
1060 
1061         if ((msg_head->flags & RX_RTR_FRAME) &&
1062             ((msg_head->nframes != 1) ||
1063              (!(msg_head->can_id & CAN_RTR_FLAG))))
1064                 return -EINVAL;
1065 
1066         /* check the given can_id */
1067         op = bcm_find_op(&bo->rx_ops, msg_head, ifindex);
1068         if (op) {
1069                 /* update existing BCM operation */
1070 
1071                 /*
1072                  * Do we need more space for the CAN frames than currently
1073                  * allocated? -> This is a _really_ unusual use-case and
1074                  * therefore (complexity / locking) it is not supported.
1075                  */
1076                 if (msg_head->nframes > op->nframes)
1077                         return -E2BIG;
1078 
1079                 if (msg_head->nframes) {
1080                         /* update CAN frames content */
1081                         err = memcpy_from_msg(op->frames, msg,
1082                                               msg_head->nframes * op->cfsiz);
1083                         if (err < 0)
1084                                 return err;
1085 
1086                         /* clear last_frames to indicate 'nothing received' */
1087                         memset(op->last_frames, 0, msg_head->nframes * op->cfsiz);
1088                 }
1089 
1090                 op->nframes = msg_head->nframes;
1091                 op->flags = msg_head->flags;
1092 
1093                 /* Only an update -> do not call can_rx_register() */
1094                 do_rx_register = 0;
1095 
1096         } else {
1097                 /* insert new BCM operation for the given can_id */
1098                 op = kzalloc(OPSIZ, GFP_KERNEL);
1099                 if (!op)
1100                         return -ENOMEM;
1101 
1102                 op->can_id = msg_head->can_id;
1103                 op->nframes = msg_head->nframes;
1104                 op->cfsiz = CFSIZ(msg_head->flags);
1105                 op->flags = msg_head->flags;
1106 
1107                 if (msg_head->nframes > 1) {
1108                         /* create array for CAN frames and copy the data */
1109                         op->frames = kmalloc(msg_head->nframes * op->cfsiz,
1110                                              GFP_KERNEL);
1111                         if (!op->frames) {
1112                                 kfree(op);
1113                                 return -ENOMEM;
1114                         }
1115 
1116                         /* create and init array for received CAN frames */
1117                         op->last_frames = kzalloc(msg_head->nframes * op->cfsiz,
1118                                                   GFP_KERNEL);
1119                         if (!op->last_frames) {
1120                                 kfree(op->frames);
1121                                 kfree(op);
1122                                 return -ENOMEM;
1123                         }
1124 
1125                 } else {
1126                         op->frames = &op->sframe;
1127                         op->last_frames = &op->last_sframe;
1128                 }
1129 
1130                 if (msg_head->nframes) {
1131                         err = memcpy_from_msg(op->frames, msg,
1132                                               msg_head->nframes * op->cfsiz);
1133                         if (err < 0) {
1134                                 if (op->frames != &op->sframe)
1135                                         kfree(op->frames);
1136                                 if (op->last_frames != &op->last_sframe)
1137                                         kfree(op->last_frames);
1138                                 kfree(op);
1139                                 return err;
1140                         }
1141                 }
1142 
1143                 /* bcm_can_tx / bcm_tx_timeout_handler needs this */
1144                 op->sk = sk;
1145                 op->ifindex = ifindex;
1146 
1147                 /* ifindex for timeout events w/o previous frame reception */
1148                 op->rx_ifindex = ifindex;
1149 
1150                 /* initialize uninitialized (kzalloc) structure */
1151                 hrtimer_init(&op->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1152                 op->timer.function = bcm_rx_timeout_handler;
1153 
1154                 /* initialize tasklet for rx timeout notification */
1155                 tasklet_init(&op->tsklet, bcm_rx_timeout_tsklet,
1156                              (unsigned long) op);
1157 
1158                 hrtimer_init(&op->thrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1159                 op->thrtimer.function = bcm_rx_thr_handler;
1160 
1161                 /* initialize tasklet for rx throttle handling */
1162                 tasklet_init(&op->thrtsklet, bcm_rx_thr_tsklet,
1163                              (unsigned long) op);
1164 
1165                 /* add this bcm_op to the list of the rx_ops */
1166                 list_add(&op->list, &bo->rx_ops);
1167 
1168                 /* call can_rx_register() */
1169                 do_rx_register = 1;
1170 
1171         } /* if ((op = bcm_find_op(&bo->rx_ops, msg_head->can_id, ifindex))) */
1172 
1173         /* check flags */
1174 
1175         if (op->flags & RX_RTR_FRAME) {
1176                 struct canfd_frame *frame0 = op->frames;
1177 
1178                 /* no timers in RTR-mode */
1179                 hrtimer_cancel(&op->thrtimer);
1180                 hrtimer_cancel(&op->timer);
1181 
1182                 /*
1183                  * funny feature in RX(!)_SETUP only for RTR-mode:
1184                  * copy can_id into frame BUT without RTR-flag to
1185                  * prevent a full-load-loopback-test ... ;-]
1186                  */
1187                 if ((op->flags & TX_CP_CAN_ID) ||
1188                     (frame0->can_id == op->can_id))
1189                         frame0->can_id = op->can_id & ~CAN_RTR_FLAG;
1190 
1191         } else {
1192                 if (op->flags & SETTIMER) {
1193 
1194                         /* set timer value */
1195                         op->ival1 = msg_head->ival1;
1196                         op->ival2 = msg_head->ival2;
1197                         op->kt_ival1 = bcm_timeval_to_ktime(msg_head->ival1);
1198                         op->kt_ival2 = bcm_timeval_to_ktime(msg_head->ival2);
1199 
1200                         /* disable an active timer due to zero value? */
1201                         if (!op->kt_ival1)
1202                                 hrtimer_cancel(&op->timer);
1203 
1204                         /*
1205                          * In any case cancel the throttle timer, flush
1206                          * potentially blocked msgs and reset throttle handling
1207                          */
1208                         op->kt_lastmsg = 0;
1209                         hrtimer_cancel(&op->thrtimer);
1210                         bcm_rx_thr_flush(op, 1);
1211                 }
1212 
1213                 if ((op->flags & STARTTIMER) && op->kt_ival1)
1214                         hrtimer_start(&op->timer, op->kt_ival1,
1215                                       HRTIMER_MODE_REL);
1216         }
1217 
1218         /* now we can register for can_ids, if we added a new bcm_op */
1219         if (do_rx_register) {
1220                 if (ifindex) {
1221                         struct net_device *dev;
1222 
1223                         dev = dev_get_by_index(&init_net, ifindex);
1224                         if (dev) {
1225                                 err = can_rx_register(dev, op->can_id,
1226                                                       REGMASK(op->can_id),
1227                                                       bcm_rx_handler, op,
1228                                                       "bcm", sk);
1229 
1230                                 op->rx_reg_dev = dev;
1231                                 dev_put(dev);
1232                         }
1233 
1234                 } else
1235                         err = can_rx_register(NULL, op->can_id,
1236                                               REGMASK(op->can_id),
1237                                               bcm_rx_handler, op, "bcm", sk);
1238                 if (err) {
1239                         /* this bcm rx op is broken -> remove it */
1240                         list_del(&op->list);
1241                         bcm_remove_op(op);
1242                         return err;
1243                 }
1244         }
1245 
1246         return msg_head->nframes * op->cfsiz + MHSIZ;
1247 }
1248 
1249 /*
1250  * bcm_tx_send - send a single CAN frame to the CAN interface (for bcm_sendmsg)
1251  */
1252 static int bcm_tx_send(struct msghdr *msg, int ifindex, struct sock *sk,
1253                        int cfsiz)
1254 {
1255         struct sk_buff *skb;
1256         struct net_device *dev;
1257         int err;
1258 
1259         /* we need a real device to send frames */
1260         if (!ifindex)
1261                 return -ENODEV;
1262 
1263         skb = alloc_skb(cfsiz + sizeof(struct can_skb_priv), GFP_KERNEL);
1264         if (!skb)
1265                 return -ENOMEM;
1266 
1267         can_skb_reserve(skb);
1268 
1269         err = memcpy_from_msg(skb_put(skb, cfsiz), msg, cfsiz);
1270         if (err < 0) {
1271                 kfree_skb(skb);
1272                 return err;
1273         }
1274 
1275         dev = dev_get_by_index(&init_net, ifindex);
1276         if (!dev) {
1277                 kfree_skb(skb);
1278                 return -ENODEV;
1279         }
1280 
1281         can_skb_prv(skb)->ifindex = dev->ifindex;
1282         can_skb_prv(skb)->skbcnt = 0;
1283         skb->dev = dev;
1284         can_skb_set_owner(skb, sk);
1285         err = can_send(skb, 1); /* send with loopback */
1286         dev_put(dev);
1287 
1288         if (err)
1289                 return err;
1290 
1291         return cfsiz + MHSIZ;
1292 }
1293 
1294 /*
1295  * bcm_sendmsg - process BCM commands (opcodes) from the userspace
1296  */
1297 static int bcm_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
1298 {
1299         struct sock *sk = sock->sk;
1300         struct bcm_sock *bo = bcm_sk(sk);
1301         int ifindex = bo->ifindex; /* default ifindex for this bcm_op */
1302         struct bcm_msg_head msg_head;
1303         int cfsiz;
1304         int ret; /* read bytes or error codes as return value */
1305 
1306         if (!bo->bound)
1307                 return -ENOTCONN;
1308 
1309         /* check for valid message length from userspace */
1310         if (size < MHSIZ)
1311                 return -EINVAL;
1312 
1313         /* read message head information */
1314         ret = memcpy_from_msg((u8 *)&msg_head, msg, MHSIZ);
1315         if (ret < 0)
1316                 return ret;
1317 
1318         cfsiz = CFSIZ(msg_head.flags);
1319         if ((size - MHSIZ) % cfsiz)
1320                 return -EINVAL;
1321 
1322         /* check for alternative ifindex for this bcm_op */
1323 
1324         if (!ifindex && msg->msg_name) {
1325                 /* no bound device as default => check msg_name */
1326                 DECLARE_SOCKADDR(struct sockaddr_can *, addr, msg->msg_name);
1327 
1328                 if (msg->msg_namelen < sizeof(*addr))
1329                         return -EINVAL;
1330 
1331                 if (addr->can_family != AF_CAN)
1332                         return -EINVAL;
1333 
1334                 /* ifindex from sendto() */
1335                 ifindex = addr->can_ifindex;
1336 
1337                 if (ifindex) {
1338                         struct net_device *dev;
1339 
1340                         dev = dev_get_by_index(&init_net, ifindex);
1341                         if (!dev)
1342                                 return -ENODEV;
1343 
1344                         if (dev->type != ARPHRD_CAN) {
1345                                 dev_put(dev);
1346                                 return -ENODEV;
1347                         }
1348 
1349                         dev_put(dev);
1350                 }
1351         }
1352 
1353         lock_sock(sk);
1354 
1355         switch (msg_head.opcode) {
1356 
1357         case TX_SETUP:
1358                 ret = bcm_tx_setup(&msg_head, msg, ifindex, sk);
1359                 break;
1360 
1361         case RX_SETUP:
1362                 ret = bcm_rx_setup(&msg_head, msg, ifindex, sk);
1363                 break;
1364 
1365         case TX_DELETE:
1366                 if (bcm_delete_tx_op(&bo->tx_ops, &msg_head, ifindex))
1367                         ret = MHSIZ;
1368                 else
1369                         ret = -EINVAL;
1370                 break;
1371 
1372         case RX_DELETE:
1373                 if (bcm_delete_rx_op(&bo->rx_ops, &msg_head, ifindex))
1374                         ret = MHSIZ;
1375                 else
1376                         ret = -EINVAL;
1377                 break;
1378 
1379         case TX_READ:
1380                 /* reuse msg_head for the reply to TX_READ */
1381                 msg_head.opcode  = TX_STATUS;
1382                 ret = bcm_read_op(&bo->tx_ops, &msg_head, ifindex);
1383                 break;
1384 
1385         case RX_READ:
1386                 /* reuse msg_head for the reply to RX_READ */
1387                 msg_head.opcode  = RX_STATUS;
1388                 ret = bcm_read_op(&bo->rx_ops, &msg_head, ifindex);
1389                 break;
1390 
1391         case TX_SEND:
1392                 /* we need exactly one CAN frame behind the msg head */
1393                 if ((msg_head.nframes != 1) || (size != cfsiz + MHSIZ))
1394                         ret = -EINVAL;
1395                 else
1396                         ret = bcm_tx_send(msg, ifindex, sk, cfsiz);
1397                 break;
1398 
1399         default:
1400                 ret = -EINVAL;
1401                 break;
1402         }
1403 
1404         release_sock(sk);
1405 
1406         return ret;
1407 }
1408 
1409 /*
1410  * notification handler for netdevice status changes
1411  */
1412 static int bcm_notifier(struct notifier_block *nb, unsigned long msg,
1413                         void *ptr)
1414 {
1415         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1416         struct bcm_sock *bo = container_of(nb, struct bcm_sock, notifier);
1417         struct sock *sk = &bo->sk;
1418         struct bcm_op *op;
1419         int notify_enodev = 0;
1420 
1421         if (!net_eq(dev_net(dev), &init_net))
1422                 return NOTIFY_DONE;
1423 
1424         if (dev->type != ARPHRD_CAN)
1425                 return NOTIFY_DONE;
1426 
1427         switch (msg) {
1428 
1429         case NETDEV_UNREGISTER:
1430                 lock_sock(sk);
1431 
1432                 /* remove device specific receive entries */
1433                 list_for_each_entry(op, &bo->rx_ops, list)
1434                         if (op->rx_reg_dev == dev)
1435                                 bcm_rx_unreg(dev, op);
1436 
1437                 /* remove device reference, if this is our bound device */
1438                 if (bo->bound && bo->ifindex == dev->ifindex) {
1439                         bo->bound   = 0;
1440                         bo->ifindex = 0;
1441                         notify_enodev = 1;
1442                 }
1443 
1444                 release_sock(sk);
1445 
1446                 if (notify_enodev) {
1447                         sk->sk_err = ENODEV;
1448                         if (!sock_flag(sk, SOCK_DEAD))
1449                                 sk->sk_error_report(sk);
1450                 }
1451                 break;
1452 
1453         case NETDEV_DOWN:
1454                 if (bo->bound && bo->ifindex == dev->ifindex) {
1455                         sk->sk_err = ENETDOWN;
1456                         if (!sock_flag(sk, SOCK_DEAD))
1457                                 sk->sk_error_report(sk);
1458                 }
1459         }
1460 
1461         return NOTIFY_DONE;
1462 }
1463 
1464 /*
1465  * initial settings for all BCM sockets to be set at socket creation time
1466  */
1467 static int bcm_init(struct sock *sk)
1468 {
1469         struct bcm_sock *bo = bcm_sk(sk);
1470 
1471         bo->bound            = 0;
1472         bo->ifindex          = 0;
1473         bo->dropped_usr_msgs = 0;
1474         bo->bcm_proc_read    = NULL;
1475 
1476         INIT_LIST_HEAD(&bo->tx_ops);
1477         INIT_LIST_HEAD(&bo->rx_ops);
1478 
1479         /* set notifier */
1480         bo->notifier.notifier_call = bcm_notifier;
1481 
1482         register_netdevice_notifier(&bo->notifier);
1483 
1484         return 0;
1485 }
1486 
1487 /*
1488  * standard socket functions
1489  */
1490 static int bcm_release(struct socket *sock)
1491 {
1492         struct sock *sk = sock->sk;
1493         struct bcm_sock *bo;
1494         struct bcm_op *op, *next;
1495 
1496         if (sk == NULL)
1497                 return 0;
1498 
1499         bo = bcm_sk(sk);
1500 
1501         /* remove bcm_ops, timer, rx_unregister(), etc. */
1502 
1503         unregister_netdevice_notifier(&bo->notifier);
1504 
1505         lock_sock(sk);
1506 
1507         list_for_each_entry_safe(op, next, &bo->tx_ops, list)
1508                 bcm_remove_op(op);
1509 
1510         list_for_each_entry_safe(op, next, &bo->rx_ops, list) {
1511                 /*
1512                  * Don't care if we're bound or not (due to netdev problems)
1513                  * can_rx_unregister() is always a save thing to do here.
1514                  */
1515                 if (op->ifindex) {
1516                         /*
1517                          * Only remove subscriptions that had not
1518                          * been removed due to NETDEV_UNREGISTER
1519                          * in bcm_notifier()
1520                          */
1521                         if (op->rx_reg_dev) {
1522                                 struct net_device *dev;
1523 
1524                                 dev = dev_get_by_index(&init_net, op->ifindex);
1525                                 if (dev) {
1526                                         bcm_rx_unreg(dev, op);
1527                                         dev_put(dev);
1528                                 }
1529                         }
1530                 } else
1531                         can_rx_unregister(NULL, op->can_id,
1532                                           REGMASK(op->can_id),
1533                                           bcm_rx_handler, op);
1534 
1535                 bcm_remove_op(op);
1536         }
1537 
1538         /* remove procfs entry */
1539         if (proc_dir && bo->bcm_proc_read)
1540                 remove_proc_entry(bo->procname, proc_dir);
1541 
1542         /* remove device reference */
1543         if (bo->bound) {
1544                 bo->bound   = 0;
1545                 bo->ifindex = 0;
1546         }
1547 
1548         sock_orphan(sk);
1549         sock->sk = NULL;
1550 
1551         release_sock(sk);
1552         sock_put(sk);
1553 
1554         return 0;
1555 }
1556 
1557 static int bcm_connect(struct socket *sock, struct sockaddr *uaddr, int len,
1558                        int flags)
1559 {
1560         struct sockaddr_can *addr = (struct sockaddr_can *)uaddr;
1561         struct sock *sk = sock->sk;
1562         struct bcm_sock *bo = bcm_sk(sk);
1563         int ret = 0;
1564 
1565         if (len < sizeof(*addr))
1566                 return -EINVAL;
1567 
1568         lock_sock(sk);
1569 
1570         if (bo->bound) {
1571                 ret = -EISCONN;
1572                 goto fail;
1573         }
1574 
1575         /* bind a device to this socket */
1576         if (addr->can_ifindex) {
1577                 struct net_device *dev;
1578 
1579                 dev = dev_get_by_index(&init_net, addr->can_ifindex);
1580                 if (!dev) {
1581                         ret = -ENODEV;
1582                         goto fail;
1583                 }
1584                 if (dev->type != ARPHRD_CAN) {
1585                         dev_put(dev);
1586                         ret = -ENODEV;
1587                         goto fail;
1588                 }
1589 
1590                 bo->ifindex = dev->ifindex;
1591                 dev_put(dev);
1592 
1593         } else {
1594                 /* no interface reference for ifindex = 0 ('any' CAN device) */
1595                 bo->ifindex = 0;
1596         }
1597 
1598         if (proc_dir) {
1599                 /* unique socket address as filename */
1600                 sprintf(bo->procname, "%lu", sock_i_ino(sk));
1601                 bo->bcm_proc_read = proc_create_data(bo->procname, 0644,
1602                                                      proc_dir,
1603                                                      &bcm_proc_fops, sk);
1604                 if (!bo->bcm_proc_read) {
1605                         ret = -ENOMEM;
1606                         goto fail;
1607                 }
1608         }
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 __init bcm_module_init(void)
1690 {
1691         int err;
1692 
1693         pr_info("can: broadcast manager protocol (rev " CAN_BCM_VERSION " t)\n");
1694 
1695         err = can_proto_register(&bcm_can_proto);
1696         if (err < 0) {
1697                 printk(KERN_ERR "can: registration of bcm protocol failed\n");
1698                 return err;
1699         }
1700 
1701         /* create /proc/net/can-bcm directory */
1702         proc_dir = proc_mkdir("can-bcm", init_net.proc_net);
1703         return 0;
1704 }
1705 
1706 static void __exit bcm_module_exit(void)
1707 {
1708         can_proto_unregister(&bcm_can_proto);
1709 
1710         if (proc_dir)
1711                 remove_proc_entry("can-bcm", init_net.proc_net);
1712 }
1713 
1714 module_init(bcm_module_init);
1715 module_exit(bcm_module_exit);
1716 

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