1// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
   2/*
   3 * bcm.c - Broadcast Manager to filter/send (cyclic) CAN content
   4 *
   5 * Copyright (c) 2002-2017 Volkswagen Group Electronic Research
   6 * All rights reserved.
   7 *
   8 * Redistribution and use in source and binary forms, with or without
   9 * modification, are permitted provided that the following conditions
  10 * are met:
  11 * 1. Redistributions of source code must retain the above copyright
  12 *    notice, this list of conditions and the following disclaimer.
  13 * 2. Redistributions in binary form must reproduce the above copyright
  14 *    notice, this list of conditions and the following disclaimer in the
  15 *    documentation and/or other materials provided with the distribution.
  16 * 3. Neither the name of Volkswagen nor the names of its contributors
  17 *    may be used to endorse or promote products derived from this software
  18 *    without specific prior written permission.
  19 *
  20 * Alternatively, provided that this notice is retained in full, this
  21 * software may be distributed under the terms of the GNU General
  22 * Public License ("GPL") version 2, in which case the provisions of the
  23 * GPL apply INSTEAD OF those given above.
  24 *
  25 * The provided data structures and external interfaces from this code
  26 * are not restricted to be used by modules with a GPL compatible license.
  27 *
  28 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  29 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  30 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  31 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  32 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  33 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  34 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  38 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
  39 * DAMAGE.
  40 *
  41 */
  42
  43#include <linux/module.h>
  44#include <linux/init.h>
  45#include <linux/interrupt.h>
  46#include <linux/hrtimer.h>
  47#include <linux/list.h>
  48#include <linux/proc_fs.h>
  49#include <linux/seq_file.h>
  50#include <linux/uio.h>
  51#include <linux/net.h>
  52#include <linux/netdevice.h>
  53#include <linux/socket.h>
  54#include <linux/if_arp.h>
  55#include <linux/skbuff.h>
  56#include <linux/can.h>
  57#include <linux/can/core.h>
  58#include <linux/can/skb.h>
  59#include <linux/can/bcm.h>
  60#include <linux/slab.h>
  61#include <net/sock.h>
  62#include <net/net_namespace.h>
  63
  64/*
  65 * To send multiple CAN frame content within TX_SETUP or to filter
  66 * CAN messages with multiplex index within RX_SETUP, the number of
  67 * different filters is limited to 256 due to the one byte index value.
  68 */
  69#define MAX_NFRAMES 256
  70
  71/* limit timers to 400 days for sending/timeouts */
  72#define BCM_TIMER_SEC_MAX (400 * 24 * 60 * 60)
  73
  74/* use of last_frames[index].flags */
  75#define RX_LOCAL   0x10 /* frame was created on the local host */
  76#define RX_OWN     0x20 /* frame was sent via the socket it was received on */
  77#define RX_RECV    0x40 /* received data for this element */
  78#define RX_THR     0x80 /* element not been sent due to throttle feature */
  79#define BCM_CAN_FLAGS_MASK 0x0F /* to clean private flags after usage */
  80
  81/* get best masking value for can_rx_register() for a given single can_id */
  82#define REGMASK(id) ((id & CAN_EFF_FLAG) ? \
  83		     (CAN_EFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG) : \
  84		     (CAN_SFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG))
  85
  86MODULE_DESCRIPTION("PF_CAN broadcast manager protocol");
  87MODULE_LICENSE("Dual BSD/GPL");
  88MODULE_AUTHOR("Oliver Hartkopp <oliver.hartkopp@volkswagen.de>");
  89MODULE_ALIAS("can-proto-2");
  90
  91#define BCM_MIN_NAMELEN CAN_REQUIRED_SIZE(struct sockaddr_can, can_ifindex)
  92
  93/*
  94 * easy access to the first 64 bit of can(fd)_frame payload. cp->data is
  95 * 64 bit aligned so the offset has to be multiples of 8 which is ensured
  96 * by the only callers in bcm_rx_cmp_to_index() bcm_rx_handler().
  97 */
  98static inline u64 get_u64(const struct canfd_frame *cp, int offset)
  99{
 100	return *(u64 *)(cp->data + offset);
 101}
 102
 103struct bcm_op {
 104	struct list_head list;
 105	struct rcu_head rcu;
 106	int ifindex;
 107	canid_t can_id;
 108	u32 flags;
 109	unsigned long frames_abs, frames_filtered;
 110	struct bcm_timeval ival1, ival2;
 111	struct hrtimer timer, thrtimer;
 112	ktime_t rx_stamp, kt_ival1, kt_ival2, kt_lastmsg;
 113	int rx_ifindex;
 114	int cfsiz;
 115	u32 count;
 116	u32 nframes;
 117	u32 currframe;
 118	/* void pointers to arrays of struct can[fd]_frame */
 119	void *frames;
 120	void *last_frames;
 121	struct canfd_frame sframe;
 122	struct canfd_frame last_sframe;
 123	struct sock *sk;
 124	struct net_device *rx_reg_dev;
 125};
 126
 127struct bcm_sock {
 128	struct sock sk;
 129	int bound;
 130	int ifindex;
 131	struct list_head notifier;
 132	struct list_head rx_ops;
 133	struct list_head tx_ops;
 134	unsigned long dropped_usr_msgs;
 135	struct proc_dir_entry *bcm_proc_read;
 136	char procname [32]; /* inode number in decimal with \0 */
 137};
 138
 139static LIST_HEAD(bcm_notifier_list);
 140static DEFINE_SPINLOCK(bcm_notifier_lock);
 141static struct bcm_sock *bcm_busy_notifier;
 142
 143/* Return pointer to store the extra msg flags for bcm_recvmsg().
 144 * We use the space of one unsigned int beyond the 'struct sockaddr_can'
 145 * in skb->cb.
 146 */
 147static inline unsigned int *bcm_flags(struct sk_buff *skb)
 148{
 149	/* return pointer after struct sockaddr_can */
 150	return (unsigned int *)(&((struct sockaddr_can *)skb->cb)[1]);
 151}
 152
 153static inline struct bcm_sock *bcm_sk(const struct sock *sk)
 154{
 155	return (struct bcm_sock *)sk;
 156}
 157
 158static inline ktime_t bcm_timeval_to_ktime(struct bcm_timeval tv)
 159{
 160	return ktime_set(tv.tv_sec, tv.tv_usec * NSEC_PER_USEC);
 161}
 162
 163/* check limitations for timeval provided by user */
 164static bool bcm_is_invalid_tv(struct bcm_msg_head *msg_head)
 165{
 166	if ((msg_head->ival1.tv_sec < 0) ||
 167	    (msg_head->ival1.tv_sec > BCM_TIMER_SEC_MAX) ||
 168	    (msg_head->ival1.tv_usec < 0) ||
 169	    (msg_head->ival1.tv_usec >= USEC_PER_SEC) ||
 170	    (msg_head->ival2.tv_sec < 0) ||
 171	    (msg_head->ival2.tv_sec > BCM_TIMER_SEC_MAX) ||
 172	    (msg_head->ival2.tv_usec < 0) ||
 173	    (msg_head->ival2.tv_usec >= USEC_PER_SEC))
 174		return true;
 175
 176	return false;
 177}
 178
 179#define CFSIZ(flags) ((flags & CAN_FD_FRAME) ? CANFD_MTU : CAN_MTU)
 180#define OPSIZ sizeof(struct bcm_op)
 181#define MHSIZ sizeof(struct bcm_msg_head)
 182
 183/*
 184 * procfs functions
 185 */
 186#if IS_ENABLED(CONFIG_PROC_FS)
 187static char *bcm_proc_getifname(struct net *net, char *result, int ifindex)
 188{
 189	struct net_device *dev;
 190
 191	if (!ifindex)
 192		return "any";
 193
 194	rcu_read_lock();
 195	dev = dev_get_by_index_rcu(net, ifindex);
 196	if (dev)
 197		strcpy(result, dev->name);
 198	else
 199		strcpy(result, "???");
 200	rcu_read_unlock();
 201
 202	return result;
 203}
 204
 205static int bcm_proc_show(struct seq_file *m, void *v)
 206{
 207	char ifname[IFNAMSIZ];
 208	struct net *net = m->private;
 209	struct sock *sk = (struct sock *)pde_data(m->file->f_inode);
 210	struct bcm_sock *bo = bcm_sk(sk);
 211	struct bcm_op *op;
 212
 213	seq_printf(m, ">>> socket %pK", sk->sk_socket);
 214	seq_printf(m, " / sk %pK", sk);
 215	seq_printf(m, " / bo %pK", bo);
 216	seq_printf(m, " / dropped %lu", bo->dropped_usr_msgs);
 217	seq_printf(m, " / bound %s", bcm_proc_getifname(net, ifname, bo->ifindex));
 218	seq_printf(m, " <<<\n");
 219
 220	list_for_each_entry(op, &bo->rx_ops, list) {
 221
 222		unsigned long reduction;
 223
 224		/* print only active entries & prevent division by zero */
 225		if (!op->frames_abs)
 226			continue;
 227
 228		seq_printf(m, "rx_op: %03X %-5s ", op->can_id,
 229			   bcm_proc_getifname(net, ifname, op->ifindex));
 230
 231		if (op->flags & CAN_FD_FRAME)
 232			seq_printf(m, "(%u)", op->nframes);
 233		else
 234			seq_printf(m, "[%u]", op->nframes);
 235
 236		seq_printf(m, "%c ", (op->flags & RX_CHECK_DLC) ? 'd' : ' ');
 237
 238		if (op->kt_ival1)
 239			seq_printf(m, "timeo=%lld ",
 240				   (long long)ktime_to_us(op->kt_ival1));
 241
 242		if (op->kt_ival2)
 243			seq_printf(m, "thr=%lld ",
 244				   (long long)ktime_to_us(op->kt_ival2));
 245
 246		seq_printf(m, "# recv %ld (%ld) => reduction: ",
 247			   op->frames_filtered, op->frames_abs);
 248
 249		reduction = 100 - (op->frames_filtered * 100) / op->frames_abs;
 250
 251		seq_printf(m, "%s%ld%%\n",
 252			   (reduction == 100) ? "near " : "", reduction);
 253	}
 254
 255	list_for_each_entry(op, &bo->tx_ops, list) {
 256
 257		seq_printf(m, "tx_op: %03X %s ", op->can_id,
 258			   bcm_proc_getifname(net, ifname, op->ifindex));
 259
 260		if (op->flags & CAN_FD_FRAME)
 261			seq_printf(m, "(%u) ", op->nframes);
 262		else
 263			seq_printf(m, "[%u] ", op->nframes);
 264
 265		if (op->kt_ival1)
 266			seq_printf(m, "t1=%lld ",
 267				   (long long)ktime_to_us(op->kt_ival1));
 268
 269		if (op->kt_ival2)
 270			seq_printf(m, "t2=%lld ",
 271				   (long long)ktime_to_us(op->kt_ival2));
 272
 273		seq_printf(m, "# sent %ld\n", op->frames_abs);
 274	}
 275	seq_putc(m, '\n');
 276	return 0;
 277}
 278#endif /* CONFIG_PROC_FS */
 279
 280/*
 281 * bcm_can_tx - send the (next) CAN frame to the appropriate CAN interface
 282 *              of the given bcm tx op
 283 */
 284static void bcm_can_tx(struct bcm_op *op)
 285{
 286	struct sk_buff *skb;
 287	struct net_device *dev;
 288	struct canfd_frame *cf = op->frames + op->cfsiz * op->currframe;
 289	int err;
 290
 291	/* no target device? => exit */
 292	if (!op->ifindex)
 293		return;
 294
 295	dev = dev_get_by_index(sock_net(op->sk), op->ifindex);
 296	if (!dev) {
 297		/* RFC: should this bcm_op remove itself here? */
 298		return;
 299	}
 300
 301	skb = alloc_skb(op->cfsiz + sizeof(struct can_skb_priv), gfp_any());
 302	if (!skb)
 303		goto out;
 304
 305	can_skb_reserve(skb);
 306	can_skb_prv(skb)->ifindex = dev->ifindex;
 307	can_skb_prv(skb)->skbcnt = 0;
 308
 309	skb_put_data(skb, cf, op->cfsiz);
 310
 311	/* send with loopback */
 312	skb->dev = dev;
 313	can_skb_set_owner(skb, op->sk);
 314	err = can_send(skb, 1);
 315	if (!err)
 316		op->frames_abs++;
 317
 318	op->currframe++;
 319
 320	/* reached last frame? */
 321	if (op->currframe >= op->nframes)
 322		op->currframe = 0;
 323out:
 324	dev_put(dev);
 325}
 326
 327/*
 328 * bcm_send_to_user - send a BCM message to the userspace
 329 *                    (consisting of bcm_msg_head + x CAN frames)
 330 */
 331static void bcm_send_to_user(struct bcm_op *op, struct bcm_msg_head *head,
 332			     struct canfd_frame *frames, int has_timestamp)
 333{
 334	struct sk_buff *skb;
 335	struct canfd_frame *firstframe;
 336	struct sockaddr_can *addr;
 337	struct sock *sk = op->sk;
 338	unsigned int datalen = head->nframes * op->cfsiz;
 339	int err;
 340	unsigned int *pflags;
 341
 342	skb = alloc_skb(sizeof(*head) + datalen, gfp_any());
 343	if (!skb)
 344		return;
 345
 346	skb_put_data(skb, head, sizeof(*head));
 347
 348	/* ensure space for sockaddr_can and msg flags */
 349	sock_skb_cb_check_size(sizeof(struct sockaddr_can) +
 350			       sizeof(unsigned int));
 351
 352	/* initialize msg flags */
 353	pflags = bcm_flags(skb);
 354	*pflags = 0;
 355
 356	if (head->nframes) {
 357		/* CAN frames starting here */
 358		firstframe = (struct canfd_frame *)skb_tail_pointer(skb);
 359
 360		skb_put_data(skb, frames, datalen);
 361
 362		/*
 363		 * the BCM uses the flags-element of the canfd_frame
 364		 * structure for internal purposes. This is only
 365		 * relevant for updates that are generated by the
 366		 * BCM, where nframes is 1
 367		 */
 368		if (head->nframes == 1) {
 369			if (firstframe->flags & RX_LOCAL)
 370				*pflags |= MSG_DONTROUTE;
 371			if (firstframe->flags & RX_OWN)
 372				*pflags |= MSG_CONFIRM;
 373
 374			firstframe->flags &= BCM_CAN_FLAGS_MASK;
 375		}
 376	}
 377
 378	if (has_timestamp) {
 379		/* restore rx timestamp */
 380		skb->tstamp = op->rx_stamp;
 381	}
 382
 383	/*
 384	 *  Put the datagram to the queue so that bcm_recvmsg() can
 385	 *  get it from there.  We need to pass the interface index to
 386	 *  bcm_recvmsg().  We pass a whole struct sockaddr_can in skb->cb
 387	 *  containing the interface index.
 388	 */
 389
 
 390	addr = (struct sockaddr_can *)skb->cb;
 391	memset(addr, 0, sizeof(*addr));
 392	addr->can_family  = AF_CAN;
 393	addr->can_ifindex = op->rx_ifindex;
 394
 395	err = sock_queue_rcv_skb(sk, skb);
 396	if (err < 0) {
 397		struct bcm_sock *bo = bcm_sk(sk);
 398
 399		kfree_skb(skb);
 400		/* don't care about overflows in this statistic */
 401		bo->dropped_usr_msgs++;
 402	}
 403}
 404
 405static bool bcm_tx_set_expiry(struct bcm_op *op, struct hrtimer *hrt)
 406{
 407	ktime_t ival;
 408
 409	if (op->kt_ival1 && op->count)
 410		ival = op->kt_ival1;
 411	else if (op->kt_ival2)
 412		ival = op->kt_ival2;
 413	else
 414		return false;
 415
 416	hrtimer_set_expires(hrt, ktime_add(ktime_get(), ival));
 417	return true;
 418}
 419
 420static void bcm_tx_start_timer(struct bcm_op *op)
 421{
 422	if (bcm_tx_set_expiry(op, &op->timer))
 423		hrtimer_start_expires(&op->timer, HRTIMER_MODE_ABS_SOFT);
 424}
 425
 426/* bcm_tx_timeout_handler - performs cyclic CAN frame transmissions */
 427static enum hrtimer_restart bcm_tx_timeout_handler(struct hrtimer *hrtimer)
 428{
 429	struct bcm_op *op = container_of(hrtimer, struct bcm_op, timer);
 430	struct bcm_msg_head msg_head;
 431
 432	if (op->kt_ival1 && (op->count > 0)) {
 433		op->count--;
 434		if (!op->count && (op->flags & TX_COUNTEVT)) {
 435
 436			/* create notification to user */
 437			memset(&msg_head, 0, sizeof(msg_head));
 438			msg_head.opcode  = TX_EXPIRED;
 439			msg_head.flags   = op->flags;
 440			msg_head.count   = op->count;
 441			msg_head.ival1   = op->ival1;
 442			msg_head.ival2   = op->ival2;
 443			msg_head.can_id  = op->can_id;
 444			msg_head.nframes = 0;
 445
 446			bcm_send_to_user(op, &msg_head, NULL, 0);
 447		}
 448		bcm_can_tx(op);
 449
 450	} else if (op->kt_ival2) {
 451		bcm_can_tx(op);
 452	}
 453
 454	return bcm_tx_set_expiry(op, &op->timer) ?
 455		HRTIMER_RESTART : HRTIMER_NORESTART;
 456}
 457
 458/*
 459 * bcm_rx_changed - create a RX_CHANGED notification due to changed content
 460 */
 461static void bcm_rx_changed(struct bcm_op *op, struct canfd_frame *data)
 462{
 463	struct bcm_msg_head head;
 464
 465	/* update statistics */
 466	op->frames_filtered++;
 467
 468	/* prevent statistics overflow */
 469	if (op->frames_filtered > ULONG_MAX/100)
 470		op->frames_filtered = op->frames_abs = 0;
 471
 472	/* this element is not throttled anymore */
 473	data->flags &= ~RX_THR;
 474
 475	memset(&head, 0, sizeof(head));
 476	head.opcode  = RX_CHANGED;
 477	head.flags   = op->flags;
 478	head.count   = op->count;
 479	head.ival1   = op->ival1;
 480	head.ival2   = op->ival2;
 481	head.can_id  = op->can_id;
 482	head.nframes = 1;
 483
 484	bcm_send_to_user(op, &head, data, 1);
 485}
 486
 487/*
 488 * bcm_rx_update_and_send - process a detected relevant receive content change
 489 *                          1. update the last received data
 490 *                          2. send a notification to the user (if possible)
 491 */
 492static void bcm_rx_update_and_send(struct bcm_op *op,
 493				   struct canfd_frame *lastdata,
 494				   const struct canfd_frame *rxdata,
 495				   unsigned char traffic_flags)
 496{
 497	memcpy(lastdata, rxdata, op->cfsiz);
 498
 499	/* mark as used and throttled by default */
 500	lastdata->flags |= (RX_RECV|RX_THR);
 501
 502	/* add own/local/remote traffic flags */
 503	lastdata->flags |= traffic_flags;
 504
 505	/* throttling mode inactive ? */
 506	if (!op->kt_ival2) {
 507		/* send RX_CHANGED to the user immediately */
 508		bcm_rx_changed(op, lastdata);
 509		return;
 510	}
 511
 512	/* with active throttling timer we are just done here */
 513	if (hrtimer_active(&op->thrtimer))
 514		return;
 515
 516	/* first reception with enabled throttling mode */
 517	if (!op->kt_lastmsg)
 518		goto rx_changed_settime;
 519
 520	/* got a second frame inside a potential throttle period? */
 521	if (ktime_us_delta(ktime_get(), op->kt_lastmsg) <
 522	    ktime_to_us(op->kt_ival2)) {
 523		/* do not send the saved data - only start throttle timer */
 524		hrtimer_start(&op->thrtimer,
 525			      ktime_add(op->kt_lastmsg, op->kt_ival2),
 526			      HRTIMER_MODE_ABS_SOFT);
 527		return;
 528	}
 529
 530	/* the gap was that big, that throttling was not needed here */
 531rx_changed_settime:
 532	bcm_rx_changed(op, lastdata);
 533	op->kt_lastmsg = ktime_get();
 534}
 535
 536/*
 537 * bcm_rx_cmp_to_index - (bit)compares the currently received data to formerly
 538 *                       received data stored in op->last_frames[]
 539 */
 540static void bcm_rx_cmp_to_index(struct bcm_op *op, unsigned int index,
 541				const struct canfd_frame *rxdata,
 542				unsigned char traffic_flags)
 543{
 544	struct canfd_frame *cf = op->frames + op->cfsiz * index;
 545	struct canfd_frame *lcf = op->last_frames + op->cfsiz * index;
 546	int i;
 547
 548	/*
 549	 * no one uses the MSBs of flags for comparison,
 550	 * so we use it here to detect the first time of reception
 551	 */
 552
 553	if (!(lcf->flags & RX_RECV)) {
 554		/* received data for the first time => send update to user */
 555		bcm_rx_update_and_send(op, lcf, rxdata, traffic_flags);
 556		return;
 557	}
 558
 559	/* do a real check in CAN frame data section */
 560	for (i = 0; i < rxdata->len; i += 8) {
 561		if ((get_u64(cf, i) & get_u64(rxdata, i)) !=
 562		    (get_u64(cf, i) & get_u64(lcf, i))) {
 563			bcm_rx_update_and_send(op, lcf, rxdata, traffic_flags);
 564			return;
 565		}
 566	}
 567
 568	if (op->flags & RX_CHECK_DLC) {
 569		/* do a real check in CAN frame length */
 570		if (rxdata->len != lcf->len) {
 571			bcm_rx_update_and_send(op, lcf, rxdata, traffic_flags);
 572			return;
 573		}
 574	}
 575}
 576
 577/*
 578 * bcm_rx_starttimer - enable timeout monitoring for CAN frame reception
 579 */
 580static void bcm_rx_starttimer(struct bcm_op *op)
 581{
 582	if (op->flags & RX_NO_AUTOTIMER)
 583		return;
 584
 585	if (op->kt_ival1)
 586		hrtimer_start(&op->timer, op->kt_ival1, HRTIMER_MODE_REL_SOFT);
 587}
 588
 589/* bcm_rx_timeout_handler - when the (cyclic) CAN frame reception timed out */
 590static enum hrtimer_restart bcm_rx_timeout_handler(struct hrtimer *hrtimer)
 591{
 592	struct bcm_op *op = container_of(hrtimer, struct bcm_op, timer);
 593	struct bcm_msg_head msg_head;
 594
 595	/* if user wants to be informed, when cyclic CAN-Messages come back */
 596	if ((op->flags & RX_ANNOUNCE_RESUME) && op->last_frames) {
 597		/* clear received CAN frames to indicate 'nothing received' */
 598		memset(op->last_frames, 0, op->nframes * op->cfsiz);
 599	}
 600
 601	/* create notification to user */
 602	memset(&msg_head, 0, sizeof(msg_head));
 603	msg_head.opcode  = RX_TIMEOUT;
 604	msg_head.flags   = op->flags;
 605	msg_head.count   = op->count;
 606	msg_head.ival1   = op->ival1;
 607	msg_head.ival2   = op->ival2;
 608	msg_head.can_id  = op->can_id;
 609	msg_head.nframes = 0;
 610
 611	bcm_send_to_user(op, &msg_head, NULL, 0);
 612
 613	return HRTIMER_NORESTART;
 614}
 615
 616/*
 617 * bcm_rx_do_flush - helper for bcm_rx_thr_flush
 618 */
 619static inline int bcm_rx_do_flush(struct bcm_op *op, unsigned int index)
 620{
 621	struct canfd_frame *lcf = op->last_frames + op->cfsiz * index;
 622
 623	if ((op->last_frames) && (lcf->flags & RX_THR)) {
 624		bcm_rx_changed(op, lcf);
 625		return 1;
 626	}
 627	return 0;
 628}
 629
 630/*
 631 * bcm_rx_thr_flush - Check for throttled data and send it to the userspace
 632 */
 633static int bcm_rx_thr_flush(struct bcm_op *op)
 634{
 635	int updated = 0;
 636
 637	if (op->nframes > 1) {
 638		unsigned int i;
 639
 640		/* for MUX filter we start at index 1 */
 641		for (i = 1; i < op->nframes; i++)
 642			updated += bcm_rx_do_flush(op, i);
 643
 644	} else {
 645		/* for RX_FILTER_ID and simple filter */
 646		updated += bcm_rx_do_flush(op, 0);
 647	}
 648
 649	return updated;
 650}
 651
 652/*
 653 * bcm_rx_thr_handler - the time for blocked content updates is over now:
 654 *                      Check for throttled data and send it to the userspace
 655 */
 656static enum hrtimer_restart bcm_rx_thr_handler(struct hrtimer *hrtimer)
 657{
 658	struct bcm_op *op = container_of(hrtimer, struct bcm_op, thrtimer);
 659
 660	if (bcm_rx_thr_flush(op)) {
 661		hrtimer_forward_now(hrtimer, op->kt_ival2);
 662		return HRTIMER_RESTART;
 663	} else {
 664		/* rearm throttle handling */
 665		op->kt_lastmsg = 0;
 666		return HRTIMER_NORESTART;
 667	}
 668}
 669
 670/*
 671 * bcm_rx_handler - handle a CAN frame reception
 672 */
 673static void bcm_rx_handler(struct sk_buff *skb, void *data)
 674{
 675	struct bcm_op *op = (struct bcm_op *)data;
 676	const struct canfd_frame *rxframe = (struct canfd_frame *)skb->data;
 677	unsigned int i;
 678	unsigned char traffic_flags;
 679
 680	if (op->can_id != rxframe->can_id)
 681		return;
 682
 683	/* make sure to handle the correct frame type (CAN / CAN FD) */
 684	if (op->flags & CAN_FD_FRAME) {
 685		if (!can_is_canfd_skb(skb))
 686			return;
 687	} else {
 688		if (!can_is_can_skb(skb))
 689			return;
 690	}
 691
 692	/* disable timeout */
 693	hrtimer_cancel(&op->timer);
 694
 695	/* save rx timestamp */
 696	op->rx_stamp = skb->tstamp;
 697	/* save originator for recvfrom() */
 698	op->rx_ifindex = skb->dev->ifindex;
 699	/* update statistics */
 700	op->frames_abs++;
 701
 702	if (op->flags & RX_RTR_FRAME) {
 703		/* send reply for RTR-request (placed in op->frames[0]) */
 704		bcm_can_tx(op);
 705		return;
 706	}
 707
 708	/* compute flags to distinguish between own/local/remote CAN traffic */
 709	traffic_flags = 0;
 710	if (skb->sk) {
 711		traffic_flags |= RX_LOCAL;
 712		if (skb->sk == op->sk)
 713			traffic_flags |= RX_OWN;
 714	}
 715
 716	if (op->flags & RX_FILTER_ID) {
 717		/* the easiest case */
 718		bcm_rx_update_and_send(op, op->last_frames, rxframe,
 719				       traffic_flags);
 720		goto rx_starttimer;
 721	}
 722
 723	if (op->nframes == 1) {
 724		/* simple compare with index 0 */
 725		bcm_rx_cmp_to_index(op, 0, rxframe, traffic_flags);
 726		goto rx_starttimer;
 727	}
 728
 729	if (op->nframes > 1) {
 730		/*
 731		 * multiplex compare
 732		 *
 733		 * find the first multiplex mask that fits.
 734		 * Remark: The MUX-mask is stored in index 0 - but only the
 735		 * first 64 bits of the frame data[] are relevant (CAN FD)
 736		 */
 737
 738		for (i = 1; i < op->nframes; i++) {
 739			if ((get_u64(op->frames, 0) & get_u64(rxframe, 0)) ==
 740			    (get_u64(op->frames, 0) &
 741			     get_u64(op->frames + op->cfsiz * i, 0))) {
 742				bcm_rx_cmp_to_index(op, i, rxframe,
 743						    traffic_flags);
 744				break;
 745			}
 746		}
 747	}
 748
 749rx_starttimer:
 750	bcm_rx_starttimer(op);
 751}
 752
 753/*
 754 * helpers for bcm_op handling: find & delete bcm [rx|tx] op elements
 755 */
 756static struct bcm_op *bcm_find_op(struct list_head *ops,
 757				  struct bcm_msg_head *mh, int ifindex)
 758{
 759	struct bcm_op *op;
 760
 761	list_for_each_entry(op, ops, list) {
 762		if ((op->can_id == mh->can_id) && (op->ifindex == ifindex) &&
 763		    (op->flags & CAN_FD_FRAME) == (mh->flags & CAN_FD_FRAME))
 764			return op;
 765	}
 766
 767	return NULL;
 768}
 769
 770static void bcm_free_op_rcu(struct rcu_head *rcu_head)
 771{
 772	struct bcm_op *op = container_of(rcu_head, struct bcm_op, rcu);
 773
 774	if ((op->frames) && (op->frames != &op->sframe))
 775		kfree(op->frames);
 776
 777	if ((op->last_frames) && (op->last_frames != &op->last_sframe))
 778		kfree(op->last_frames);
 779
 780	kfree(op);
 781}
 782
 783static void bcm_remove_op(struct bcm_op *op)
 784{
 785	hrtimer_cancel(&op->timer);
 786	hrtimer_cancel(&op->thrtimer);
 787
 788	call_rcu(&op->rcu, bcm_free_op_rcu);
 789}
 790
 791static void bcm_rx_unreg(struct net_device *dev, struct bcm_op *op)
 792{
 793	if (op->rx_reg_dev == dev) {
 794		can_rx_unregister(dev_net(dev), dev, op->can_id,
 795				  REGMASK(op->can_id), bcm_rx_handler, op);
 796
 797		/* mark as removed subscription */
 798		op->rx_reg_dev = NULL;
 799	} else
 800		printk(KERN_ERR "can-bcm: bcm_rx_unreg: registered device "
 801		       "mismatch %p %p\n", op->rx_reg_dev, dev);
 802}
 803
 804/*
 805 * bcm_delete_rx_op - find and remove a rx op (returns number of removed ops)
 806 */
 807static int bcm_delete_rx_op(struct list_head *ops, struct bcm_msg_head *mh,
 808			    int ifindex)
 809{
 810	struct bcm_op *op, *n;
 811
 812	list_for_each_entry_safe(op, n, ops, list) {
 813		if ((op->can_id == mh->can_id) && (op->ifindex == ifindex) &&
 814		    (op->flags & CAN_FD_FRAME) == (mh->flags & CAN_FD_FRAME)) {
 815
 816			/* disable automatic timer on frame reception */
 817			op->flags |= RX_NO_AUTOTIMER;
 818
 819			/*
 820			 * Don't care if we're bound or not (due to netdev
 821			 * problems) can_rx_unregister() is always a save
 822			 * thing to do here.
 823			 */
 824			if (op->ifindex) {
 825				/*
 826				 * Only remove subscriptions that had not
 827				 * been removed due to NETDEV_UNREGISTER
 828				 * in bcm_notifier()
 829				 */
 830				if (op->rx_reg_dev) {
 831					struct net_device *dev;
 832
 833					dev = dev_get_by_index(sock_net(op->sk),
 834							       op->ifindex);
 835					if (dev) {
 836						bcm_rx_unreg(dev, op);
 837						dev_put(dev);
 838					}
 839				}
 840			} else
 841				can_rx_unregister(sock_net(op->sk), NULL,
 842						  op->can_id,
 843						  REGMASK(op->can_id),
 844						  bcm_rx_handler, op);
 845
 846			list_del(&op->list);
 847			bcm_remove_op(op);
 848			return 1; /* done */
 849		}
 850	}
 851
 852	return 0; /* not found */
 853}
 854
 855/*
 856 * bcm_delete_tx_op - find and remove a tx op (returns number of removed ops)
 857 */
 858static int bcm_delete_tx_op(struct list_head *ops, struct bcm_msg_head *mh,
 859			    int ifindex)
 860{
 861	struct bcm_op *op, *n;
 862
 863	list_for_each_entry_safe(op, n, ops, list) {
 864		if ((op->can_id == mh->can_id) && (op->ifindex == ifindex) &&
 865		    (op->flags & CAN_FD_FRAME) == (mh->flags & CAN_FD_FRAME)) {
 866			list_del(&op->list);
 867			bcm_remove_op(op);
 868			return 1; /* done */
 869		}
 870	}
 871
 872	return 0; /* not found */
 873}
 874
 875/*
 876 * bcm_read_op - read out a bcm_op and send it to the user (for bcm_sendmsg)
 877 */
 878static int bcm_read_op(struct list_head *ops, struct bcm_msg_head *msg_head,
 879		       int ifindex)
 880{
 881	struct bcm_op *op = bcm_find_op(ops, msg_head, ifindex);
 882
 883	if (!op)
 884		return -EINVAL;
 885
 886	/* put current values into msg_head */
 887	msg_head->flags   = op->flags;
 888	msg_head->count   = op->count;
 889	msg_head->ival1   = op->ival1;
 890	msg_head->ival2   = op->ival2;
 891	msg_head->nframes = op->nframes;
 892
 893	bcm_send_to_user(op, msg_head, op->frames, 0);
 894
 895	return MHSIZ;
 896}
 897
 898/*
 899 * bcm_tx_setup - create or update a bcm tx op (for bcm_sendmsg)
 900 */
 901static int bcm_tx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
 902			int ifindex, struct sock *sk)
 903{
 904	struct bcm_sock *bo = bcm_sk(sk);
 905	struct bcm_op *op;
 906	struct canfd_frame *cf;
 907	unsigned int i;
 908	int err;
 909
 910	/* we need a real device to send frames */
 911	if (!ifindex)
 912		return -ENODEV;
 913
 914	/* check nframes boundaries - we need at least one CAN frame */
 915	if (msg_head->nframes < 1 || msg_head->nframes > MAX_NFRAMES)
 916		return -EINVAL;
 917
 918	/* check timeval limitations */
 919	if ((msg_head->flags & SETTIMER) && bcm_is_invalid_tv(msg_head))
 920		return -EINVAL;
 921
 922	/* check the given can_id */
 923	op = bcm_find_op(&bo->tx_ops, msg_head, ifindex);
 924	if (op) {
 925		/* update existing BCM operation */
 926
 927		/*
 928		 * Do we need more space for the CAN frames than currently
 929		 * allocated? -> This is a _really_ unusual use-case and
 930		 * therefore (complexity / locking) it is not supported.
 931		 */
 932		if (msg_head->nframes > op->nframes)
 933			return -E2BIG;
 934
 935		/* update CAN frames content */
 936		for (i = 0; i < msg_head->nframes; i++) {
 937
 938			cf = op->frames + op->cfsiz * i;
 939			err = memcpy_from_msg((u8 *)cf, msg, op->cfsiz);
 940
 941			if (op->flags & CAN_FD_FRAME) {
 942				if (cf->len > 64)
 943					err = -EINVAL;
 944			} else {
 945				if (cf->len > 8)
 946					err = -EINVAL;
 947			}
 948
 949			if (err < 0)
 950				return err;
 951
 952			if (msg_head->flags & TX_CP_CAN_ID) {
 953				/* copy can_id into frame */
 954				cf->can_id = msg_head->can_id;
 955			}
 956		}
 957		op->flags = msg_head->flags;
 958
 959	} else {
 960		/* insert new BCM operation for the given can_id */
 961
 962		op = kzalloc(OPSIZ, GFP_KERNEL);
 963		if (!op)
 964			return -ENOMEM;
 965
 966		op->can_id = msg_head->can_id;
 967		op->cfsiz = CFSIZ(msg_head->flags);
 968		op->flags = msg_head->flags;
 969
 970		/* create array for CAN frames and copy the data */
 971		if (msg_head->nframes > 1) {
 972			op->frames = kmalloc_array(msg_head->nframes,
 973						   op->cfsiz,
 974						   GFP_KERNEL);
 975			if (!op->frames) {
 976				kfree(op);
 977				return -ENOMEM;
 978			}
 979		} else
 980			op->frames = &op->sframe;
 981
 982		for (i = 0; i < msg_head->nframes; i++) {
 983
 984			cf = op->frames + op->cfsiz * i;
 985			err = memcpy_from_msg((u8 *)cf, msg, op->cfsiz);
 986			if (err < 0)
 987				goto free_op;
 988
 989			if (op->flags & CAN_FD_FRAME) {
 990				if (cf->len > 64)
 991					err = -EINVAL;
 992			} else {
 993				if (cf->len > 8)
 994					err = -EINVAL;
 995			}
 996
 997			if (err < 0)
 998				goto free_op;
 999
1000			if (msg_head->flags & TX_CP_CAN_ID) {
1001				/* copy can_id into frame */
1002				cf->can_id = msg_head->can_id;
1003			}
1004		}
1005
1006		/* tx_ops never compare with previous received messages */
1007		op->last_frames = NULL;
1008
1009		/* bcm_can_tx / bcm_tx_timeout_handler needs this */
1010		op->sk = sk;
1011		op->ifindex = ifindex;
1012
1013		/* initialize uninitialized (kzalloc) structure */
1014		hrtimer_init(&op->timer, CLOCK_MONOTONIC,
1015			     HRTIMER_MODE_REL_SOFT);
1016		op->timer.function = bcm_tx_timeout_handler;
1017
1018		/* currently unused in tx_ops */
1019		hrtimer_init(&op->thrtimer, CLOCK_MONOTONIC,
1020			     HRTIMER_MODE_REL_SOFT);
1021
1022		/* add this bcm_op to the list of the tx_ops */
1023		list_add(&op->list, &bo->tx_ops);
1024
1025	} /* if ((op = bcm_find_op(&bo->tx_ops, msg_head->can_id, ifindex))) */
1026
1027	if (op->nframes != msg_head->nframes) {
1028		op->nframes   = msg_head->nframes;
1029		/* start multiple frame transmission with index 0 */
1030		op->currframe = 0;
1031	}
1032
1033	/* check flags */
1034
1035	if (op->flags & TX_RESET_MULTI_IDX) {
1036		/* start multiple frame transmission with index 0 */
1037		op->currframe = 0;
1038	}
1039
1040	if (op->flags & SETTIMER) {
1041		/* set timer values */
1042		op->count = msg_head->count;
1043		op->ival1 = msg_head->ival1;
1044		op->ival2 = msg_head->ival2;
1045		op->kt_ival1 = bcm_timeval_to_ktime(msg_head->ival1);
1046		op->kt_ival2 = bcm_timeval_to_ktime(msg_head->ival2);
1047
1048		/* disable an active timer due to zero values? */
1049		if (!op->kt_ival1 && !op->kt_ival2)
1050			hrtimer_cancel(&op->timer);
1051	}
1052
1053	if (op->flags & STARTTIMER) {
1054		hrtimer_cancel(&op->timer);
1055		/* spec: send CAN frame when starting timer */
1056		op->flags |= TX_ANNOUNCE;
1057	}
1058
1059	if (op->flags & TX_ANNOUNCE) {
1060		bcm_can_tx(op);
1061		if (op->count)
1062			op->count--;
1063	}
1064
1065	if (op->flags & STARTTIMER)
1066		bcm_tx_start_timer(op);
1067
1068	return msg_head->nframes * op->cfsiz + MHSIZ;
1069
1070free_op:
1071	if (op->frames != &op->sframe)
1072		kfree(op->frames);
1073	kfree(op);
1074	return err;
1075}
1076
1077/*
1078 * bcm_rx_setup - create or update a bcm rx op (for bcm_sendmsg)
1079 */
1080static int bcm_rx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
1081			int ifindex, struct sock *sk)
1082{
1083	struct bcm_sock *bo = bcm_sk(sk);
1084	struct bcm_op *op;
1085	int do_rx_register;
1086	int err = 0;
1087
1088	if ((msg_head->flags & RX_FILTER_ID) || (!(msg_head->nframes))) {
1089		/* be robust against wrong usage ... */
1090		msg_head->flags |= RX_FILTER_ID;
1091		/* ignore trailing garbage */
1092		msg_head->nframes = 0;
1093	}
1094
1095	/* the first element contains the mux-mask => MAX_NFRAMES + 1  */
1096	if (msg_head->nframes > MAX_NFRAMES + 1)
1097		return -EINVAL;
1098
1099	if ((msg_head->flags & RX_RTR_FRAME) &&
1100	    ((msg_head->nframes != 1) ||
1101	     (!(msg_head->can_id & CAN_RTR_FLAG))))
1102		return -EINVAL;
1103
1104	/* check timeval limitations */
1105	if ((msg_head->flags & SETTIMER) && bcm_is_invalid_tv(msg_head))
1106		return -EINVAL;
1107
1108	/* check the given can_id */
1109	op = bcm_find_op(&bo->rx_ops, msg_head, ifindex);
1110	if (op) {
1111		/* update existing BCM operation */
1112
1113		/*
1114		 * Do we need more space for the CAN frames than currently
1115		 * allocated? -> This is a _really_ unusual use-case and
1116		 * therefore (complexity / locking) it is not supported.
1117		 */
1118		if (msg_head->nframes > op->nframes)
1119			return -E2BIG;
1120
1121		if (msg_head->nframes) {
1122			/* update CAN frames content */
1123			err = memcpy_from_msg(op->frames, msg,
1124					      msg_head->nframes * op->cfsiz);
1125			if (err < 0)
1126				return err;
1127
1128			/* clear last_frames to indicate 'nothing received' */
1129			memset(op->last_frames, 0, msg_head->nframes * op->cfsiz);
1130		}
1131
1132		op->nframes = msg_head->nframes;
1133		op->flags = msg_head->flags;
1134
1135		/* Only an update -> do not call can_rx_register() */
1136		do_rx_register = 0;
1137
1138	} else {
1139		/* insert new BCM operation for the given can_id */
1140		op = kzalloc(OPSIZ, GFP_KERNEL);
1141		if (!op)
1142			return -ENOMEM;
1143
1144		op->can_id = msg_head->can_id;
1145		op->nframes = msg_head->nframes;
1146		op->cfsiz = CFSIZ(msg_head->flags);
1147		op->flags = msg_head->flags;
1148
1149		if (msg_head->nframes > 1) {
1150			/* create array for CAN frames and copy the data */
1151			op->frames = kmalloc_array(msg_head->nframes,
1152						   op->cfsiz,
1153						   GFP_KERNEL);
1154			if (!op->frames) {
1155				kfree(op);
1156				return -ENOMEM;
1157			}
1158
1159			/* create and init array for received CAN frames */
1160			op->last_frames = kcalloc(msg_head->nframes,
1161						  op->cfsiz,
1162						  GFP_KERNEL);
1163			if (!op->last_frames) {
1164				kfree(op->frames);
1165				kfree(op);
1166				return -ENOMEM;
1167			}
1168
1169		} else {
1170			op->frames = &op->sframe;
1171			op->last_frames = &op->last_sframe;
1172		}
1173
1174		if (msg_head->nframes) {
1175			err = memcpy_from_msg(op->frames, msg,
1176					      msg_head->nframes * op->cfsiz);
1177			if (err < 0) {
1178				if (op->frames != &op->sframe)
1179					kfree(op->frames);
1180				if (op->last_frames != &op->last_sframe)
1181					kfree(op->last_frames);
1182				kfree(op);
1183				return err;
1184			}
1185		}
1186
1187		/* bcm_can_tx / bcm_tx_timeout_handler needs this */
1188		op->sk = sk;
1189		op->ifindex = ifindex;
1190
1191		/* ifindex for timeout events w/o previous frame reception */
1192		op->rx_ifindex = ifindex;
1193
1194		/* initialize uninitialized (kzalloc) structure */
1195		hrtimer_init(&op->timer, CLOCK_MONOTONIC,
1196			     HRTIMER_MODE_REL_SOFT);
1197		op->timer.function = bcm_rx_timeout_handler;
1198
1199		hrtimer_init(&op->thrtimer, CLOCK_MONOTONIC,
1200			     HRTIMER_MODE_REL_SOFT);
1201		op->thrtimer.function = bcm_rx_thr_handler;
1202
1203		/* add this bcm_op to the list of the rx_ops */
1204		list_add(&op->list, &bo->rx_ops);
1205
1206		/* call can_rx_register() */
1207		do_rx_register = 1;
1208
1209	} /* if ((op = bcm_find_op(&bo->rx_ops, msg_head->can_id, ifindex))) */
1210
1211	/* check flags */
1212
1213	if (op->flags & RX_RTR_FRAME) {
1214		struct canfd_frame *frame0 = op->frames;
1215
1216		/* no timers in RTR-mode */
1217		hrtimer_cancel(&op->thrtimer);
1218		hrtimer_cancel(&op->timer);
1219
1220		/*
1221		 * funny feature in RX(!)_SETUP only for RTR-mode:
1222		 * copy can_id into frame BUT without RTR-flag to
1223		 * prevent a full-load-loopback-test ... ;-]
1224		 */
1225		if ((op->flags & TX_CP_CAN_ID) ||
1226		    (frame0->can_id == op->can_id))
1227			frame0->can_id = op->can_id & ~CAN_RTR_FLAG;
1228
1229	} else {
1230		if (op->flags & SETTIMER) {
1231
1232			/* set timer value */
1233			op->ival1 = msg_head->ival1;
1234			op->ival2 = msg_head->ival2;
1235			op->kt_ival1 = bcm_timeval_to_ktime(msg_head->ival1);
1236			op->kt_ival2 = bcm_timeval_to_ktime(msg_head->ival2);
1237
1238			/* disable an active timer due to zero value? */
1239			if (!op->kt_ival1)
1240				hrtimer_cancel(&op->timer);
1241
1242			/*
1243			 * In any case cancel the throttle timer, flush
1244			 * potentially blocked msgs and reset throttle handling
1245			 */
1246			op->kt_lastmsg = 0;
1247			hrtimer_cancel(&op->thrtimer);
1248			bcm_rx_thr_flush(op);
1249		}
1250
1251		if ((op->flags & STARTTIMER) && op->kt_ival1)
1252			hrtimer_start(&op->timer, op->kt_ival1,
1253				      HRTIMER_MODE_REL_SOFT);
1254	}
1255
1256	/* now we can register for can_ids, if we added a new bcm_op */
1257	if (do_rx_register) {
1258		if (ifindex) {
1259			struct net_device *dev;
1260
1261			dev = dev_get_by_index(sock_net(sk), ifindex);
1262			if (dev) {
1263				err = can_rx_register(sock_net(sk), dev,
1264						      op->can_id,
1265						      REGMASK(op->can_id),
1266						      bcm_rx_handler, op,
1267						      "bcm", sk);
1268
1269				op->rx_reg_dev = dev;
1270				dev_put(dev);
1271			}
1272
1273		} else
1274			err = can_rx_register(sock_net(sk), NULL, op->can_id,
1275					      REGMASK(op->can_id),
1276					      bcm_rx_handler, op, "bcm", sk);
1277		if (err) {
1278			/* this bcm rx op is broken -> remove it */
1279			list_del(&op->list);
1280			bcm_remove_op(op);
1281			return err;
1282		}
1283	}
1284
1285	return msg_head->nframes * op->cfsiz + MHSIZ;
1286}
1287
1288/*
1289 * bcm_tx_send - send a single CAN frame to the CAN interface (for bcm_sendmsg)
1290 */
1291static int bcm_tx_send(struct msghdr *msg, int ifindex, struct sock *sk,
1292		       int cfsiz)
1293{
1294	struct sk_buff *skb;
1295	struct net_device *dev;
1296	int err;
1297
1298	/* we need a real device to send frames */
1299	if (!ifindex)
1300		return -ENODEV;
1301
1302	skb = alloc_skb(cfsiz + sizeof(struct can_skb_priv), GFP_KERNEL);
1303	if (!skb)
1304		return -ENOMEM;
1305
1306	can_skb_reserve(skb);
1307
1308	err = memcpy_from_msg(skb_put(skb, cfsiz), msg, cfsiz);
1309	if (err < 0) {
1310		kfree_skb(skb);
1311		return err;
1312	}
1313
1314	dev = dev_get_by_index(sock_net(sk), ifindex);
1315	if (!dev) {
1316		kfree_skb(skb);
1317		return -ENODEV;
1318	}
1319
1320	can_skb_prv(skb)->ifindex = dev->ifindex;
1321	can_skb_prv(skb)->skbcnt = 0;
1322	skb->dev = dev;
1323	can_skb_set_owner(skb, sk);
1324	err = can_send(skb, 1); /* send with loopback */
1325	dev_put(dev);
1326
1327	if (err)
1328		return err;
1329
1330	return cfsiz + MHSIZ;
1331}
1332
1333/*
1334 * bcm_sendmsg - process BCM commands (opcodes) from the userspace
1335 */
1336static int bcm_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
1337{
1338	struct sock *sk = sock->sk;
1339	struct bcm_sock *bo = bcm_sk(sk);
1340	int ifindex = bo->ifindex; /* default ifindex for this bcm_op */
1341	struct bcm_msg_head msg_head;
1342	int cfsiz;
1343	int ret; /* read bytes or error codes as return value */
1344
1345	if (!bo->bound)
1346		return -ENOTCONN;
1347
1348	/* check for valid message length from userspace */
1349	if (size < MHSIZ)
1350		return -EINVAL;
1351
1352	/* read message head information */
1353	ret = memcpy_from_msg((u8 *)&msg_head, msg, MHSIZ);
1354	if (ret < 0)
1355		return ret;
1356
1357	cfsiz = CFSIZ(msg_head.flags);
1358	if ((size - MHSIZ) % cfsiz)
1359		return -EINVAL;
1360
1361	/* check for alternative ifindex for this bcm_op */
1362
1363	if (!ifindex && msg->msg_name) {
1364		/* no bound device as default => check msg_name */
1365		DECLARE_SOCKADDR(struct sockaddr_can *, addr, msg->msg_name);
1366
1367		if (msg->msg_namelen < BCM_MIN_NAMELEN)
1368			return -EINVAL;
1369
1370		if (addr->can_family != AF_CAN)
1371			return -EINVAL;
1372
1373		/* ifindex from sendto() */
1374		ifindex = addr->can_ifindex;
1375
1376		if (ifindex) {
1377			struct net_device *dev;
1378
1379			dev = dev_get_by_index(sock_net(sk), ifindex);
1380			if (!dev)
1381				return -ENODEV;
1382
1383			if (dev->type != ARPHRD_CAN) {
1384				dev_put(dev);
1385				return -ENODEV;
1386			}
1387
1388			dev_put(dev);
1389		}
1390	}
1391
1392	lock_sock(sk);
1393
1394	switch (msg_head.opcode) {
1395
1396	case TX_SETUP:
1397		ret = bcm_tx_setup(&msg_head, msg, ifindex, sk);
1398		break;
1399
1400	case RX_SETUP:
1401		ret = bcm_rx_setup(&msg_head, msg, ifindex, sk);
1402		break;
1403
1404	case TX_DELETE:
1405		if (bcm_delete_tx_op(&bo->tx_ops, &msg_head, ifindex))
1406			ret = MHSIZ;
1407		else
1408			ret = -EINVAL;
1409		break;
1410
1411	case RX_DELETE:
1412		if (bcm_delete_rx_op(&bo->rx_ops, &msg_head, ifindex))
1413			ret = MHSIZ;
1414		else
1415			ret = -EINVAL;
1416		break;
1417
1418	case TX_READ:
1419		/* reuse msg_head for the reply to TX_READ */
1420		msg_head.opcode  = TX_STATUS;
1421		ret = bcm_read_op(&bo->tx_ops, &msg_head, ifindex);
1422		break;
1423
1424	case RX_READ:
1425		/* reuse msg_head for the reply to RX_READ */
1426		msg_head.opcode  = RX_STATUS;
1427		ret = bcm_read_op(&bo->rx_ops, &msg_head, ifindex);
1428		break;
1429
1430	case TX_SEND:
1431		/* we need exactly one CAN frame behind the msg head */
1432		if ((msg_head.nframes != 1) || (size != cfsiz + MHSIZ))
1433			ret = -EINVAL;
1434		else
1435			ret = bcm_tx_send(msg, ifindex, sk, cfsiz);
1436		break;
1437
1438	default:
1439		ret = -EINVAL;
1440		break;
1441	}
1442
1443	release_sock(sk);
1444
1445	return ret;
1446}
1447
1448/*
1449 * notification handler for netdevice status changes
1450 */
1451static void bcm_notify(struct bcm_sock *bo, unsigned long msg,
1452		       struct net_device *dev)
1453{
1454	struct sock *sk = &bo->sk;
1455	struct bcm_op *op;
1456	int notify_enodev = 0;
1457
1458	if (!net_eq(dev_net(dev), sock_net(sk)))
1459		return;
1460
1461	switch (msg) {
1462
1463	case NETDEV_UNREGISTER:
1464		lock_sock(sk);
1465
1466		/* remove device specific receive entries */
1467		list_for_each_entry(op, &bo->rx_ops, list)
1468			if (op->rx_reg_dev == dev)
1469				bcm_rx_unreg(dev, op);
1470
1471		/* remove device reference, if this is our bound device */
1472		if (bo->bound && bo->ifindex == dev->ifindex) {
1473#if IS_ENABLED(CONFIG_PROC_FS)
1474			if (sock_net(sk)->can.bcmproc_dir && bo->bcm_proc_read) {
1475				remove_proc_entry(bo->procname, sock_net(sk)->can.bcmproc_dir);
1476				bo->bcm_proc_read = NULL;
1477			}
1478#endif
1479			bo->bound   = 0;
1480			bo->ifindex = 0;
1481			notify_enodev = 1;
1482		}
1483
1484		release_sock(sk);
1485
1486		if (notify_enodev) {
1487			sk->sk_err = ENODEV;
1488			if (!sock_flag(sk, SOCK_DEAD))
1489				sk_error_report(sk);
1490		}
1491		break;
1492
1493	case NETDEV_DOWN:
1494		if (bo->bound && bo->ifindex == dev->ifindex) {
1495			sk->sk_err = ENETDOWN;
1496			if (!sock_flag(sk, SOCK_DEAD))
1497				sk_error_report(sk);
1498		}
1499	}
1500}
1501
1502static int bcm_notifier(struct notifier_block *nb, unsigned long msg,
1503			void *ptr)
1504{
1505	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1506
1507	if (dev->type != ARPHRD_CAN)
1508		return NOTIFY_DONE;
1509	if (msg != NETDEV_UNREGISTER && msg != NETDEV_DOWN)
1510		return NOTIFY_DONE;
1511	if (unlikely(bcm_busy_notifier)) /* Check for reentrant bug. */
1512		return NOTIFY_DONE;
1513
1514	spin_lock(&bcm_notifier_lock);
1515	list_for_each_entry(bcm_busy_notifier, &bcm_notifier_list, notifier) {
1516		spin_unlock(&bcm_notifier_lock);
1517		bcm_notify(bcm_busy_notifier, msg, dev);
1518		spin_lock(&bcm_notifier_lock);
1519	}
1520	bcm_busy_notifier = NULL;
1521	spin_unlock(&bcm_notifier_lock);
1522	return NOTIFY_DONE;
1523}
1524
1525/*
1526 * initial settings for all BCM sockets to be set at socket creation time
1527 */
1528static int bcm_init(struct sock *sk)
1529{
1530	struct bcm_sock *bo = bcm_sk(sk);
1531
1532	bo->bound            = 0;
1533	bo->ifindex          = 0;
1534	bo->dropped_usr_msgs = 0;
1535	bo->bcm_proc_read    = NULL;
1536
1537	INIT_LIST_HEAD(&bo->tx_ops);
1538	INIT_LIST_HEAD(&bo->rx_ops);
1539
1540	/* set notifier */
1541	spin_lock(&bcm_notifier_lock);
1542	list_add_tail(&bo->notifier, &bcm_notifier_list);
1543	spin_unlock(&bcm_notifier_lock);
1544
1545	return 0;
1546}
1547
1548/*
1549 * standard socket functions
1550 */
1551static int bcm_release(struct socket *sock)
1552{
1553	struct sock *sk = sock->sk;
1554	struct net *net;
1555	struct bcm_sock *bo;
1556	struct bcm_op *op, *next;
1557
1558	if (!sk)
1559		return 0;
1560
1561	net = sock_net(sk);
1562	bo = bcm_sk(sk);
1563
1564	/* remove bcm_ops, timer, rx_unregister(), etc. */
1565
1566	spin_lock(&bcm_notifier_lock);
1567	while (bcm_busy_notifier == bo) {
1568		spin_unlock(&bcm_notifier_lock);
1569		schedule_timeout_uninterruptible(1);
1570		spin_lock(&bcm_notifier_lock);
1571	}
1572	list_del(&bo->notifier);
1573	spin_unlock(&bcm_notifier_lock);
1574
1575	lock_sock(sk);
1576
1577#if IS_ENABLED(CONFIG_PROC_FS)
1578	/* remove procfs entry */
1579	if (net->can.bcmproc_dir && bo->bcm_proc_read)
1580		remove_proc_entry(bo->procname, net->can.bcmproc_dir);
1581#endif /* CONFIG_PROC_FS */
1582
1583	list_for_each_entry_safe(op, next, &bo->tx_ops, list)
1584		bcm_remove_op(op);
1585
1586	list_for_each_entry_safe(op, next, &bo->rx_ops, list) {
1587		/*
1588		 * Don't care if we're bound or not (due to netdev problems)
1589		 * can_rx_unregister() is always a save thing to do here.
1590		 */
1591		if (op->ifindex) {
1592			/*
1593			 * Only remove subscriptions that had not
1594			 * been removed due to NETDEV_UNREGISTER
1595			 * in bcm_notifier()
1596			 */
1597			if (op->rx_reg_dev) {
1598				struct net_device *dev;
1599
1600				dev = dev_get_by_index(net, op->ifindex);
1601				if (dev) {
1602					bcm_rx_unreg(dev, op);
1603					dev_put(dev);
1604				}
1605			}
1606		} else
1607			can_rx_unregister(net, NULL, op->can_id,
1608					  REGMASK(op->can_id),
1609					  bcm_rx_handler, op);
1610
1611	}
1612
1613	synchronize_rcu();
1614
1615	list_for_each_entry_safe(op, next, &bo->rx_ops, list)
1616		bcm_remove_op(op);
1617
1618	/* remove device reference */
1619	if (bo->bound) {
1620		bo->bound   = 0;
1621		bo->ifindex = 0;
1622	}
1623
1624	sock_orphan(sk);
1625	sock->sk = NULL;
1626
1627	release_sock(sk);
1628	sock_put(sk);
1629
1630	return 0;
1631}
1632
1633static int bcm_connect(struct socket *sock, struct sockaddr *uaddr, int len,
1634		       int flags)
1635{
1636	struct sockaddr_can *addr = (struct sockaddr_can *)uaddr;
1637	struct sock *sk = sock->sk;
1638	struct bcm_sock *bo = bcm_sk(sk);
1639	struct net *net = sock_net(sk);
1640	int ret = 0;
1641
1642	if (len < BCM_MIN_NAMELEN)
1643		return -EINVAL;
1644
1645	lock_sock(sk);
1646
1647	if (bo->bound) {
1648		ret = -EISCONN;
1649		goto fail;
1650	}
1651
1652	/* bind a device to this socket */
1653	if (addr->can_ifindex) {
1654		struct net_device *dev;
1655
1656		dev = dev_get_by_index(net, addr->can_ifindex);
1657		if (!dev) {
1658			ret = -ENODEV;
1659			goto fail;
1660		}
1661		if (dev->type != ARPHRD_CAN) {
1662			dev_put(dev);
1663			ret = -ENODEV;
1664			goto fail;
1665		}
1666
1667		bo->ifindex = dev->ifindex;
1668		dev_put(dev);
1669
1670	} else {
1671		/* no interface reference for ifindex = 0 ('any' CAN device) */
1672		bo->ifindex = 0;
1673	}
1674
1675#if IS_ENABLED(CONFIG_PROC_FS)
1676	if (net->can.bcmproc_dir) {
1677		/* unique socket address as filename */
1678		sprintf(bo->procname, "%lu", sock_i_ino(sk));
1679		bo->bcm_proc_read = proc_create_net_single(bo->procname, 0644,
1680						     net->can.bcmproc_dir,
1681						     bcm_proc_show, sk);
1682		if (!bo->bcm_proc_read) {
1683			ret = -ENOMEM;
1684			goto fail;
1685		}
1686	}
1687#endif /* CONFIG_PROC_FS */
1688
1689	bo->bound = 1;
1690
1691fail:
1692	release_sock(sk);
1693
1694	return ret;
1695}
1696
1697static int bcm_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
1698		       int flags)
1699{
1700	struct sock *sk = sock->sk;
1701	struct sk_buff *skb;
1702	int error = 0;
1703	int err;
1704
1705	skb = skb_recv_datagram(sk, flags, &error);
1706	if (!skb)
1707		return error;
1708
1709	if (skb->len < size)
1710		size = skb->len;
1711
1712	err = memcpy_to_msg(msg, skb->data, size);
1713	if (err < 0) {
1714		skb_free_datagram(sk, skb);
1715		return err;
1716	}
1717
1718	sock_recv_cmsgs(msg, sk, skb);
1719
1720	if (msg->msg_name) {
1721		__sockaddr_check_size(BCM_MIN_NAMELEN);
1722		msg->msg_namelen = BCM_MIN_NAMELEN;
1723		memcpy(msg->msg_name, skb->cb, msg->msg_namelen);
1724	}
1725
1726	/* assign the flags that have been recorded in bcm_send_to_user() */
1727	msg->msg_flags |= *(bcm_flags(skb));
1728
1729	skb_free_datagram(sk, skb);
1730
1731	return size;
1732}
1733
1734static int bcm_sock_no_ioctlcmd(struct socket *sock, unsigned int cmd,
1735				unsigned long arg)
1736{
1737	/* no ioctls for socket layer -> hand it down to NIC layer */
1738	return -ENOIOCTLCMD;
1739}
1740
1741static const struct proto_ops bcm_ops = {
1742	.family        = PF_CAN,
1743	.release       = bcm_release,
1744	.bind          = sock_no_bind,
1745	.connect       = bcm_connect,
1746	.socketpair    = sock_no_socketpair,
1747	.accept        = sock_no_accept,
1748	.getname       = sock_no_getname,
1749	.poll          = datagram_poll,
1750	.ioctl         = bcm_sock_no_ioctlcmd,
1751	.gettstamp     = sock_gettstamp,
1752	.listen        = sock_no_listen,
1753	.shutdown      = sock_no_shutdown,
1754	.sendmsg       = bcm_sendmsg,
1755	.recvmsg       = bcm_recvmsg,
1756	.mmap          = sock_no_mmap,
1757};
1758
1759static struct proto bcm_proto __read_mostly = {
1760	.name       = "CAN_BCM",
1761	.owner      = THIS_MODULE,
1762	.obj_size   = sizeof(struct bcm_sock),
1763	.init       = bcm_init,
1764};
1765
1766static const struct can_proto bcm_can_proto = {
1767	.type       = SOCK_DGRAM,
1768	.protocol   = CAN_BCM,
1769	.ops        = &bcm_ops,
1770	.prot       = &bcm_proto,
1771};
1772
1773static int canbcm_pernet_init(struct net *net)
1774{
1775#if IS_ENABLED(CONFIG_PROC_FS)
1776	/* create /proc/net/can-bcm directory */
1777	net->can.bcmproc_dir = proc_net_mkdir(net, "can-bcm", net->proc_net);
1778#endif /* CONFIG_PROC_FS */
1779
1780	return 0;
1781}
1782
1783static void canbcm_pernet_exit(struct net *net)
1784{
1785#if IS_ENABLED(CONFIG_PROC_FS)
1786	/* remove /proc/net/can-bcm directory */
1787	if (net->can.bcmproc_dir)
1788		remove_proc_entry("can-bcm", net->proc_net);
1789#endif /* CONFIG_PROC_FS */
1790}
1791
1792static struct pernet_operations canbcm_pernet_ops __read_mostly = {
1793	.init = canbcm_pernet_init,
1794	.exit = canbcm_pernet_exit,
1795};
1796
1797static struct notifier_block canbcm_notifier = {
1798	.notifier_call = bcm_notifier
1799};
1800
1801static int __init bcm_module_init(void)
1802{
1803	int err;
1804
1805	pr_info("can: broadcast manager protocol\n");
1806
1807	err = register_pernet_subsys(&canbcm_pernet_ops);
1808	if (err)
1809		return err;
1810
1811	err = register_netdevice_notifier(&canbcm_notifier);
1812	if (err)
1813		goto register_notifier_failed;
1814
1815	err = can_proto_register(&bcm_can_proto);
1816	if (err < 0) {
1817		printk(KERN_ERR "can: registration of bcm protocol failed\n");
1818		goto register_proto_failed;
1819	}
1820
1821	return 0;
1822
1823register_proto_failed:
1824	unregister_netdevice_notifier(&canbcm_notifier);
1825register_notifier_failed:
1826	unregister_pernet_subsys(&canbcm_pernet_ops);
1827	return err;
1828}
1829
1830static void __exit bcm_module_exit(void)
1831{
1832	can_proto_unregister(&bcm_can_proto);
1833	unregister_netdevice_notifier(&canbcm_notifier);
1834	unregister_pernet_subsys(&canbcm_pernet_ops);
1835}
1836
1837module_init(bcm_module_init);
1838module_exit(bcm_module_exit);