text: /*
   * bcm.c - Broadcast Manager to filter/send (cyclic) CAN content
   *
   * Copyright (c) 2002-2007 Volkswagen Group Electronic Research
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. Neither the name of Volkswagen nor the names of its contributors
   *    may be used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * Alternatively, provided that this notice is retained in full, this
   * software may be distributed under the terms of the GNU General
   * Public License ("GPL") version 2, in which case the provisions of the
   * GPL apply INSTEAD OF those given above.
   *
   * The provided data structures and external interfaces from this code
   * are not restricted to be used by modules with a GPL compatible license.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
   * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
   * DAMAGE.
   *
   */
  
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/interrupt.h>
  #include <linux/hrtimer.h>
  #include <linux/list.h>
  #include <linux/proc_fs.h>
  #include <linux/seq_file.h>
  #include <linux/uio.h>
  #include <linux/net.h>
  #include <linux/netdevice.h>
  #include <linux/socket.h>
  #include <linux/if_arp.h>
  #include <linux/skbuff.h>
  #include <linux/can.h>
  #include <linux/can/core.h>
  #include <linux/can/skb.h>
  #include <linux/can/bcm.h>
  #include <linux/slab.h>
  #include <net/sock.h>
  #include <net/net_namespace.h>
  
  /*
   * To send multiple CAN frame content within TX_SETUP or to filter
   * CAN messages with multiplex index within RX_SETUP, the number of
   * different filters is limited to 256 due to the one byte index value.
   */
  #define MAX_NFRAMES 256
  
  /* use of last_frames[index].can_dlc */
  #define RX_RECV    0x40 /* received data for this element */
  #define RX_THR     0x80 /* element not been sent due to throttle feature */
  #define BCM_CAN_DLC_MASK 0x0F /* clean private flags in can_dlc by masking */
  
  /* get best masking value for can_rx_register() for a given single can_id */
  #define REGMASK(id) ((id & CAN_EFF_FLAG) ? \
  		     (CAN_EFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG) : \
  		     (CAN_SFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG))
  
  #define CAN_BCM_VERSION CAN_VERSION
  static __initconst const char banner[] = KERN_INFO
  	"can: broadcast manager protocol (rev " CAN_BCM_VERSION " t)\n";
  
  MODULE_DESCRIPTION("PF_CAN broadcast manager protocol");
  MODULE_LICENSE("Dual BSD/GPL");
  MODULE_AUTHOR("Oliver Hartkopp <oliver.hartkopp@volkswagen.de>");
  MODULE_ALIAS("can-proto-2");
  
  /* easy access to can_frame payload */
  static inline u64 GET_U64(const struct can_frame *cp)
  {
  	return *(u64 *)cp->data;
  }
  
  struct bcm_op {
  	struct list_head list;
  	int ifindex;
  	canid_t can_id;
  	u32 flags;
  	unsigned long frames_abs, frames_filtered;
  	struct timeval ival1, ival2;
  	struct hrtimer timer, thrtimer;
  	struct tasklet_struct tsklet, thrtsklet;
  	ktime_t rx_stamp, kt_ival1, kt_ival2, kt_lastmsg;
  	int rx_ifindex;
  	u32 count;
  	u32 nframes;
  	u32 currframe;
  	struct can_frame *frames;
  	struct can_frame *last_frames;
  	struct can_frame sframe;
  	struct can_frame last_sframe;
  	struct sock *sk;
  	struct net_device *rx_reg_dev;
  };
  
  static struct proc_dir_entry *proc_dir;
  
  struct bcm_sock {
  	struct sock sk;
  	int bound;
  	int ifindex;
  	struct notifier_block notifier;
  	struct list_head rx_ops;
  	struct list_head tx_ops;
  	unsigned long dropped_usr_msgs;
  	struct proc_dir_entry *bcm_proc_read;
  	char procname [32]; /* inode number in decimal with \0 */
  };
  
  static inline struct bcm_sock *bcm_sk(const struct sock *sk)
  {
  	return (struct bcm_sock *)sk;
  }
  
  #define CFSIZ sizeof(struct can_frame)
  #define OPSIZ sizeof(struct bcm_op)
  #define MHSIZ sizeof(struct bcm_msg_head)
  
  /*
   * procfs functions
   */
  static char *bcm_proc_getifname(char *result, int ifindex)
  {
  	struct net_device *dev;
  
  	if (!ifindex)
  		return "any";
  
  	rcu_read_lock();
  	dev = dev_get_by_index_rcu(&init_net, ifindex);
  	if (dev)
  		strcpy(result, dev->name);
  	else
  		strcpy(result, "???");
  	rcu_read_unlock();
  
  	return result;
  }
  
  static int bcm_proc_show(struct seq_file *m, void *v)
  {
  	char ifname[IFNAMSIZ];
  	struct sock *sk = (struct sock *)m->private;
  	struct bcm_sock *bo = bcm_sk(sk);
  	struct bcm_op *op;
  
  	seq_printf(m, ">>> socket %pK", sk->sk_socket);
  	seq_printf(m, " / sk %pK", sk);
  	seq_printf(m, " / bo %pK", bo);
  	seq_printf(m, " / dropped %lu", bo->dropped_usr_msgs);
  	seq_printf(m, " / bound %s", bcm_proc_getifname(ifname, bo->ifindex));
  	seq_printf(m, " <<<\n");
  
  	list_for_each_entry(op, &bo->rx_ops, list) {
  
  		unsigned long reduction;
  
  		/* print only active entries & prevent division by zero */
  		if (!op->frames_abs)
  			continue;
  
  		seq_printf(m, "rx_op: %03X %-5s ",
  				op->can_id, bcm_proc_getifname(ifname, op->ifindex));
  		seq_printf(m, "[%u]%c ", op->nframes,
  				(op->flags & RX_CHECK_DLC)?'d':' ');
  		if (op->kt_ival1.tv64)
  			seq_printf(m, "timeo=%lld ",
  					(long long)
  					ktime_to_us(op->kt_ival1));
  
  		if (op->kt_ival2.tv64)
  			seq_printf(m, "thr=%lld ",
  					(long long)
  					ktime_to_us(op->kt_ival2));
  
  		seq_printf(m, "# recv %ld (%ld) => reduction: ",
  				op->frames_filtered, op->frames_abs);
  
  		reduction = 100 - (op->frames_filtered * 100) / op->frames_abs;
  
  		seq_printf(m, "%s%ld%%\n",
  				(reduction == 100)?"near ":"", reduction);
  	}
  
  	list_for_each_entry(op, &bo->tx_ops, list) {
  
  		seq_printf(m, "tx_op: %03X %s [%u] ",
  				op->can_id,
  				bcm_proc_getifname(ifname, op->ifindex),
  				op->nframes);
  
  		if (op->kt_ival1.tv64)
  			seq_printf(m, "t1=%lld ",
  					(long long) ktime_to_us(op->kt_ival1));
  
  		if (op->kt_ival2.tv64)
  			seq_printf(m, "t2=%lld ",
  					(long long) ktime_to_us(op->kt_ival2));
  
  		seq_printf(m, "# sent %ld\n", op->frames_abs);
  	}
  	seq_putc(m, '\n');
  	return 0;
  }
  
  static int bcm_proc_open(struct inode *inode, struct file *file)
  {
  	return single_open(file, bcm_proc_show, PDE_DATA(inode));
  }
  
  static const struct file_operations bcm_proc_fops = {
  	.owner		= THIS_MODULE,
  	.open		= bcm_proc_open,
  	.read		= seq_read,
  	.llseek		= seq_lseek,
  	.release	= single_release,
  };
  
  /*
   * bcm_can_tx - send the (next) CAN frame to the appropriate CAN interface
   *              of the given bcm tx op
   */
  static void bcm_can_tx(struct bcm_op *op)
  {
  	struct sk_buff *skb;
  	struct net_device *dev;
  	struct can_frame *cf = &op->frames[op->currframe];
  
  	/* no target device? => exit */
  	if (!op->ifindex)
  		return;
  
  	dev = dev_get_by_index(&init_net, op->ifindex);
  	if (!dev) {
  		/* RFC: should this bcm_op remove itself here? */
  		return;
  	}
  
  	skb = alloc_skb(CFSIZ + sizeof(struct can_skb_priv), gfp_any());
  	if (!skb)
  		goto out;
  
  	can_skb_reserve(skb);
  	can_skb_prv(skb)->ifindex = dev->ifindex;
  
  	memcpy(skb_put(skb, CFSIZ), cf, CFSIZ);
  
  	/* send with loopback */
  	skb->dev = dev;
  	can_skb_set_owner(skb, op->sk);
  	can_send(skb, 1);
  
  	/* update statistics */
  	op->currframe++;
  	op->frames_abs++;
  
  	/* reached last frame? */
  	if (op->currframe >= op->nframes)
  		op->currframe = 0;
   out:
  	dev_put(dev);
  }
  
  /*
   * bcm_send_to_user - send a BCM message to the userspace
   *                    (consisting of bcm_msg_head + x CAN frames)
   */
  static void bcm_send_to_user(struct bcm_op *op, struct bcm_msg_head *head,
  			     struct can_frame *frames, int has_timestamp)
  {
  	struct sk_buff *skb;
  	struct can_frame *firstframe;
  	struct sockaddr_can *addr;
  	struct sock *sk = op->sk;
  	unsigned int datalen = head->nframes * CFSIZ;
  	int err;
  
  	skb = alloc_skb(sizeof(*head) + datalen, gfp_any());
  	if (!skb)
  		return;
  
  	memcpy(skb_put(skb, sizeof(*head)), head, sizeof(*head));
  
  	if (head->nframes) {
  		/* can_frames starting here */
  		firstframe = (struct can_frame *)skb_tail_pointer(skb);
  
  		memcpy(skb_put(skb, datalen), frames, datalen);
  
  		/*
  		 * the BCM uses the can_dlc-element of the can_frame
  		 * structure for internal purposes. This is only
  		 * relevant for updates that are generated by the
  		 * BCM, where nframes is 1
  		 */
  		if (head->nframes == 1)
  			firstframe->can_dlc &= BCM_CAN_DLC_MASK;
  	}
  
  	if (has_timestamp) {
  		/* restore rx timestamp */
  		skb->tstamp = op->rx_stamp;
  	}
  
  	/*
  	 *  Put the datagram to the queue so that bcm_recvmsg() can
  	 *  get it from there.  We need to pass the interface index to
  	 *  bcm_recvmsg().  We pass a whole struct sockaddr_can in skb->cb
  	 *  containing the interface index.
  	 */
  
  	BUILD_BUG_ON(sizeof(skb->cb) < sizeof(struct sockaddr_can));
  	addr = (struct sockaddr_can *)skb->cb;
  	memset(addr, 0, sizeof(*addr));
  	addr->can_family  = AF_CAN;
  	addr->can_ifindex = op->rx_ifindex;
  
  	err = sock_queue_rcv_skb(sk, skb);
  	if (err < 0) {
  		struct bcm_sock *bo = bcm_sk(sk);
  
  		kfree_skb(skb);
  		/* don't care about overflows in this statistic */
  		bo->dropped_usr_msgs++;
  	}
  }
  
  static void bcm_tx_start_timer(struct bcm_op *op)
  {
  	if (op->kt_ival1.tv64 && op->count)
  		hrtimer_start(&op->timer,
  			      ktime_add(ktime_get(), op->kt_ival1),
  			      HRTIMER_MODE_ABS);
  	else if (op->kt_ival2.tv64)
  		hrtimer_start(&op->timer,
  			      ktime_add(ktime_get(), op->kt_ival2),
  			      HRTIMER_MODE_ABS);
  }
  
  static void bcm_tx_timeout_tsklet(unsigned long data)
  {
  	struct bcm_op *op = (struct bcm_op *)data;
  	struct bcm_msg_head msg_head;
  
  	if (op->kt_ival1.tv64 && (op->count > 0)) {
  
  		op->count--;
  		if (!op->count && (op->flags & TX_COUNTEVT)) {
  
  			/* create notification to user */
  			msg_head.opcode  = TX_EXPIRED;
  			msg_head.flags   = op->flags;
  			msg_head.count   = op->count;
  			msg_head.ival1   = op->ival1;
  			msg_head.ival2   = op->ival2;
  			msg_head.can_id  = op->can_id;
  			msg_head.nframes = 0;
  
  			bcm_send_to_user(op, &msg_head, NULL, 0);
  		}
  		bcm_can_tx(op);
  
  	} else if (op->kt_ival2.tv64)
  		bcm_can_tx(op);
  
  	bcm_tx_start_timer(op);
  }
  
  /*
   * bcm_tx_timeout_handler - performs cyclic CAN frame transmissions
   */
  static enum hrtimer_restart bcm_tx_timeout_handler(struct hrtimer *hrtimer)
  {
  	struct bcm_op *op = container_of(hrtimer, struct bcm_op, timer);
  
  	tasklet_schedule(&op->tsklet);
  
  	return HRTIMER_NORESTART;
  }
  
  /*
   * bcm_rx_changed - create a RX_CHANGED notification due to changed content
   */
  static void bcm_rx_changed(struct bcm_op *op, struct can_frame *data)
  {
  	struct bcm_msg_head head;
  
  	/* update statistics */
  	op->frames_filtered++;
  
  	/* prevent statistics overflow */
  	if (op->frames_filtered > ULONG_MAX/100)
  		op->frames_filtered = op->frames_abs = 0;
  
  	/* this element is not throttled anymore */
  	data->can_dlc &= (BCM_CAN_DLC_MASK|RX_RECV);
  
  	head.opcode  = RX_CHANGED;
  	head.flags   = op->flags;
  	head.count   = op->count;
  	head.ival1   = op->ival1;
  	head.ival2   = op->ival2;
  	head.can_id  = op->can_id;
  	head.nframes = 1;
  
  	bcm_send_to_user(op, &head, data, 1);
  }
  
  /*
   * bcm_rx_update_and_send - process a detected relevant receive content change
   *                          1. update the last received data
   *                          2. send a notification to the user (if possible)
   */
  static void bcm_rx_update_and_send(struct bcm_op *op,
  				   struct can_frame *lastdata,
  				   const struct can_frame *rxdata)
  {
  	memcpy(lastdata, rxdata, CFSIZ);
  
  	/* mark as used and throttled by default */
  	lastdata->can_dlc |= (RX_RECV|RX_THR);
  
  	/* throtteling mode inactive ? */
  	if (!op->kt_ival2.tv64) {
  		/* send RX_CHANGED to the user immediately */
  		bcm_rx_changed(op, lastdata);
  		return;
  	}
  
  	/* with active throttling timer we are just done here */
  	if (hrtimer_active(&op->thrtimer))
  		return;
  
  	/* first receiption with enabled throttling mode */
  	if (!op->kt_lastmsg.tv64)
  		goto rx_changed_settime;
  
  	/* got a second frame inside a potential throttle period? */
  	if (ktime_us_delta(ktime_get(), op->kt_lastmsg) <
  	    ktime_to_us(op->kt_ival2)) {
  		/* do not send the saved data - only start throttle timer */
  		hrtimer_start(&op->thrtimer,
  			      ktime_add(op->kt_lastmsg, op->kt_ival2),
  			      HRTIMER_MODE_ABS);
  		return;
  	}
  
  	/* the gap was that big, that throttling was not needed here */
  rx_changed_settime:
  	bcm_rx_changed(op, lastdata);
  	op->kt_lastmsg = ktime_get();
  }
  
  /*
   * bcm_rx_cmp_to_index - (bit)compares the currently received data to formerly
   *                       received data stored in op->last_frames[]
   */
  static void bcm_rx_cmp_to_index(struct bcm_op *op, unsigned int index,
  				const struct can_frame *rxdata)
  {
  	/*
  	 * no one uses the MSBs of can_dlc for comparation,
  	 * so we use it here to detect the first time of reception
  	 */
  
  	if (!(op->last_frames[index].can_dlc & RX_RECV)) {
  		/* received data for the first time => send update to user */
  		bcm_rx_update_and_send(op, &op->last_frames[index], rxdata);
  		return;
  	}
  
  	/* do a real check in can_frame data section */
  
  	if ((GET_U64(&op->frames[index]) & GET_U64(rxdata)) !=
  	    (GET_U64(&op->frames[index]) & GET_U64(&op->last_frames[index]))) {
  		bcm_rx_update_and_send(op, &op->last_frames[index], rxdata);
  		return;
  	}
  
  	if (op->flags & RX_CHECK_DLC) {
  		/* do a real check in can_frame dlc */
  		if (rxdata->can_dlc != (op->last_frames[index].can_dlc &
  					BCM_CAN_DLC_MASK)) {
  			bcm_rx_update_and_send(op, &op->last_frames[index],
  					       rxdata);
  			return;
  		}
  	}
  }
  
  /*
   * bcm_rx_starttimer - enable timeout monitoring for CAN frame receiption
   */
  static void bcm_rx_starttimer(struct bcm_op *op)
  {
  	if (op->flags & RX_NO_AUTOTIMER)
  		return;
  
  	if (op->kt_ival1.tv64)
  		hrtimer_start(&op->timer, op->kt_ival1, HRTIMER_MODE_REL);
  }
  
  static void bcm_rx_timeout_tsklet(unsigned long data)
  {
  	struct bcm_op *op = (struct bcm_op *)data;
  	struct bcm_msg_head msg_head;
  
  	/* create notification to user */
  	msg_head.opcode  = RX_TIMEOUT;
  	msg_head.flags   = op->flags;
  	msg_head.count   = op->count;
  	msg_head.ival1   = op->ival1;
  	msg_head.ival2   = op->ival2;
  	msg_head.can_id  = op->can_id;
  	msg_head.nframes = 0;
  
  	bcm_send_to_user(op, &msg_head, NULL, 0);
  }
  
  /*
   * bcm_rx_timeout_handler - when the (cyclic) CAN frame receiption timed out
   */
  static enum hrtimer_restart bcm_rx_timeout_handler(struct hrtimer *hrtimer)
  {
  	struct bcm_op *op = container_of(hrtimer, struct bcm_op, timer);
  
  	/* schedule before NET_RX_SOFTIRQ */
  	tasklet_hi_schedule(&op->tsklet);
  
  	/* no restart of the timer is done here! */
  
  	/* if user wants to be informed, when cyclic CAN-Messages come back */
  	if ((op->flags & RX_ANNOUNCE_RESUME) && op->last_frames) {
  		/* clear received can_frames to indicate 'nothing received' */
  		memset(op->last_frames, 0, op->nframes * CFSIZ);
  	}
  
  	return HRTIMER_NORESTART;
  }
  
  /*
   * bcm_rx_do_flush - helper for bcm_rx_thr_flush
   */
  static inline int bcm_rx_do_flush(struct bcm_op *op, int update,
  				  unsigned int index)
  {
  	if ((op->last_frames) && (op->last_frames[index].can_dlc & RX_THR)) {
  		if (update)
  			bcm_rx_changed(op, &op->last_frames[index]);
  		return 1;
  	}
  	return 0;
  }
  
  /*
   * bcm_rx_thr_flush - Check for throttled data and send it to the userspace
   *
   * update == 0 : just check if throttled data is available  (any irq context)
   * update == 1 : check and send throttled data to userspace (soft_irq context)
   */
  static int bcm_rx_thr_flush(struct bcm_op *op, int update)
  {
  	int updated = 0;
  
  	if (op->nframes > 1) {
  		unsigned int i;
  
  		/* for MUX filter we start at index 1 */
  		for (i = 1; i < op->nframes; i++)
  			updated += bcm_rx_do_flush(op, update, i);
  
  	} else {
  		/* for RX_FILTER_ID and simple filter */
  		updated += bcm_rx_do_flush(op, update, 0);
  	}
  
  	return updated;
  }
  
  static void bcm_rx_thr_tsklet(unsigned long data)
  {
  	struct bcm_op *op = (struct bcm_op *)data;
  
  	/* push the changed data to the userspace */
  	bcm_rx_thr_flush(op, 1);
  }
  
  /*
   * bcm_rx_thr_handler - the time for blocked content updates is over now:
   *                      Check for throttled data and send it to the userspace
   */
  static enum hrtimer_restart bcm_rx_thr_handler(struct hrtimer *hrtimer)
  {
  	struct bcm_op *op = container_of(hrtimer, struct bcm_op, thrtimer);
  
  	tasklet_schedule(&op->thrtsklet);
  
  	if (bcm_rx_thr_flush(op, 0)) {
  		hrtimer_forward(hrtimer, ktime_get(), op->kt_ival2);
  		return HRTIMER_RESTART;
  	} else {
  		/* rearm throttle handling */
  		op->kt_lastmsg = ktime_set(0, 0);
  		return HRTIMER_NORESTART;
  	}
  }
  
  /*
   * bcm_rx_handler - handle a CAN frame receiption
   */
  static void bcm_rx_handler(struct sk_buff *skb, void *data)
  {
  	struct bcm_op *op = (struct bcm_op *)data;
  	const struct can_frame *rxframe = (struct can_frame *)skb->data;
  	unsigned int i;
  
  	/* disable timeout */
  	hrtimer_cancel(&op->timer);
  
  	if (op->can_id != rxframe->can_id)
  		return;
  
  	/* save rx timestamp */
  	op->rx_stamp = skb->tstamp;
  	/* save originator for recvfrom() */
  	op->rx_ifindex = skb->dev->ifindex;
  	/* update statistics */
  	op->frames_abs++;
  
  	if (op->flags & RX_RTR_FRAME) {
  		/* send reply for RTR-request (placed in op->frames[0]) */
  		bcm_can_tx(op);
  		return;
  	}
  
  	if (op->flags & RX_FILTER_ID) {
  		/* the easiest case */
  		bcm_rx_update_and_send(op, &op->last_frames[0], rxframe);
  		goto rx_starttimer;
  	}
  
  	if (op->nframes == 1) {
  		/* simple compare with index 0 */
  		bcm_rx_cmp_to_index(op, 0, rxframe);
  		goto rx_starttimer;
  	}
  
  	if (op->nframes > 1) {
  		/*
  		 * multiplex compare
  		 *
  		 * find the first multiplex mask that fits.
  		 * Remark: The MUX-mask is stored in index 0
  		 */
  
  		for (i = 1; i < op->nframes; i++) {
  			if ((GET_U64(&op->frames[0]) & GET_U64(rxframe)) ==
  			    (GET_U64(&op->frames[0]) &
  			     GET_U64(&op->frames[i]))) {
  				bcm_rx_cmp_to_index(op, i, rxframe);
  				break;
  			}
  		}
  	}
  
  rx_starttimer:
  	bcm_rx_starttimer(op);
  }
  
  /*
   * helpers for bcm_op handling: find & delete bcm [rx|tx] op elements
   */
  static struct bcm_op *bcm_find_op(struct list_head *ops, canid_t can_id,
  				  int ifindex)
  {
  	struct bcm_op *op;
  
  	list_for_each_entry(op, ops, list) {
  		if ((op->can_id == can_id) && (op->ifindex == ifindex))
  			return op;
  	}
  
  	return NULL;
  }
  
  static void bcm_remove_op(struct bcm_op *op)
  {
  	hrtimer_cancel(&op->timer);
  	hrtimer_cancel(&op->thrtimer);
  
  	if (op->tsklet.func)
  		tasklet_kill(&op->tsklet);
  
  	if (op->thrtsklet.func)
  		tasklet_kill(&op->thrtsklet);
  
  	if ((op->frames) && (op->frames != &op->sframe))
  		kfree(op->frames);
  
  	if ((op->last_frames) && (op->last_frames != &op->last_sframe))
  		kfree(op->last_frames);
  
  	kfree(op);
  }
  
  static void bcm_rx_unreg(struct net_device *dev, struct bcm_op *op)
  {
  	if (op->rx_reg_dev == dev) {
  		can_rx_unregister(dev, op->can_id, REGMASK(op->can_id),
  				  bcm_rx_handler, op);
  
  		/* mark as removed subscription */
  		op->rx_reg_dev = NULL;
  	} else
  		printk(KERN_ERR "can-bcm: bcm_rx_unreg: registered device "
  		       "mismatch %p %p\n", op->rx_reg_dev, dev);
  }
  
  /*
   * bcm_delete_rx_op - find and remove a rx op (returns number of removed ops)
   */
  static int bcm_delete_rx_op(struct list_head *ops, canid_t can_id, int ifindex)
  {
  	struct bcm_op *op, *n;
  
  	list_for_each_entry_safe(op, n, ops, list) {
  		if ((op->can_id == can_id) && (op->ifindex == ifindex)) {
  
  			/*
  			 * Don't care if we're bound or not (due to netdev
  			 * problems) can_rx_unregister() is always a save
  			 * thing to do here.
  			 */
  			if (op->ifindex) {
  				/*
  				 * Only remove subscriptions that had not
  				 * been removed due to NETDEV_UNREGISTER
  				 * in bcm_notifier()
  				 */
  				if (op->rx_reg_dev) {
  					struct net_device *dev;
  
  					dev = dev_get_by_index(&init_net,
  							       op->ifindex);
  					if (dev) {
  						bcm_rx_unreg(dev, op);
  						dev_put(dev);
  					}
  				}
  			} else
  				can_rx_unregister(NULL, op->can_id,
  						  REGMASK(op->can_id),
  						  bcm_rx_handler, op);
  
  			list_del(&op->list);
  			bcm_remove_op(op);
  			return 1; /* done */
  		}
  	}
  
  	return 0; /* not found */
  }
  
  /*
   * bcm_delete_tx_op - find and remove a tx op (returns number of removed ops)
   */
  static int bcm_delete_tx_op(struct list_head *ops, canid_t can_id, int ifindex)
  {
  	struct bcm_op *op, *n;
  
  	list_for_each_entry_safe(op, n, ops, list) {
  		if ((op->can_id == can_id) && (op->ifindex == ifindex)) {
  			list_del(&op->list);
  			bcm_remove_op(op);
  			return 1; /* done */
  		}
  	}
  
  	return 0; /* not found */
  }
  
  /*
   * bcm_read_op - read out a bcm_op and send it to the user (for bcm_sendmsg)
   */
  static int bcm_read_op(struct list_head *ops, struct bcm_msg_head *msg_head,
  		       int ifindex)
  {
  	struct bcm_op *op = bcm_find_op(ops, msg_head->can_id, ifindex);
  
  	if (!op)
  		return -EINVAL;
  
  	/* put current values into msg_head */
  	msg_head->flags   = op->flags;
  	msg_head->count   = op->count;
  	msg_head->ival1   = op->ival1;
  	msg_head->ival2   = op->ival2;
  	msg_head->nframes = op->nframes;
  
  	bcm_send_to_user(op, msg_head, op->frames, 0);
  
  	return MHSIZ;
  }
  
  /*
   * bcm_tx_setup - create or update a bcm tx op (for bcm_sendmsg)
   */
  static int bcm_tx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
  			int ifindex, struct sock *sk)
  {
  	struct bcm_sock *bo = bcm_sk(sk);
  	struct bcm_op *op;
  	unsigned int i;
  	int err;
  
  	/* we need a real device to send frames */
  	if (!ifindex)
  		return -ENODEV;
  
  	/* check nframes boundaries - we need at least one can_frame */
  	if (msg_head->nframes < 1 || msg_head->nframes > MAX_NFRAMES)
  		return -EINVAL;
  
  	/* check the given can_id */
  	op = bcm_find_op(&bo->tx_ops, msg_head->can_id, ifindex);
  
  	if (op) {
  		/* update existing BCM operation */
  
  		/*
  		 * Do we need more space for the can_frames than currently
  		 * allocated? -> This is a _really_ unusual use-case and
  		 * therefore (complexity / locking) it is not supported.
  		 */
  		if (msg_head->nframes > op->nframes)
  			return -E2BIG;
  
  		/* update can_frames content */
  		for (i = 0; i < msg_head->nframes; i++) {
  			err = memcpy_fromiovec((u8 *)&op->frames[i],
  					       msg->msg_iov, CFSIZ);
  
  			if (op->frames[i].can_dlc > 8)
  				err = -EINVAL;
  
  			if (err < 0)
  				return err;
  
  			if (msg_head->flags & TX_CP_CAN_ID) {
  				/* copy can_id into frame */
  				op->frames[i].can_id = msg_head->can_id;
  			}
  		}
  
  	} else {
  		/* insert new BCM operation for the given can_id */
  
  		op = kzalloc(OPSIZ, GFP_KERNEL);
  		if (!op)
  			return -ENOMEM;
  
  		op->can_id    = msg_head->can_id;
  
  		/* create array for can_frames and copy the data */
  		if (msg_head->nframes > 1) {
  			op->frames = kmalloc(msg_head->nframes * CFSIZ,
  					     GFP_KERNEL);
  			if (!op->frames) {
  				kfree(op);
  				return -ENOMEM;
  			}
  		} else
  			op->frames = &op->sframe;
  
  		for (i = 0; i < msg_head->nframes; i++) {
  			err = memcpy_fromiovec((u8 *)&op->frames[i],
  					       msg->msg_iov, CFSIZ);
  
  			if (op->frames[i].can_dlc > 8)
  				err = -EINVAL;
  
  			if (err < 0) {
  				if (op->frames != &op->sframe)
  					kfree(op->frames);
  				kfree(op);
  				return err;
  			}
  
  			if (msg_head->flags & TX_CP_CAN_ID) {
  				/* copy can_id into frame */
  				op->frames[i].can_id = msg_head->can_id;
  			}
  		}
  
  		/* tx_ops never compare with previous received messages */
  		op->last_frames = NULL;
  
  		/* bcm_can_tx / bcm_tx_timeout_handler needs this */
  		op->sk = sk;
  		op->ifindex = ifindex;
  
  		/* initialize uninitialized (kzalloc) structure */
  		hrtimer_init(&op->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
  		op->timer.function = bcm_tx_timeout_handler;
  
  		/* initialize tasklet for tx countevent notification */
  		tasklet_init(&op->tsklet, bcm_tx_timeout_tsklet,
  			     (unsigned long) op);
  
  		/* currently unused in tx_ops */
  		hrtimer_init(&op->thrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
  
  		/* add this bcm_op to the list of the tx_ops */
  		list_add(&op->list, &bo->tx_ops);
  
  	} /* if ((op = bcm_find_op(&bo->tx_ops, msg_head->can_id, ifindex))) */
  
  	if (op->nframes != msg_head->nframes) {
  		op->nframes   = msg_head->nframes;
  		/* start multiple frame transmission with index 0 */
  		op->currframe = 0;
  	}
  
  	/* check flags */
  
  	op->flags = msg_head->flags;
  
  	if (op->flags & TX_RESET_MULTI_IDX) {
  		/* start multiple frame transmission with index 0 */
  		op->currframe = 0;
  	}
  
  	if (op->flags & SETTIMER) {
  		/* set timer values */
  		op->count = msg_head->count;
  		op->ival1 = msg_head->ival1;
  		op->ival2 = msg_head->ival2;
  		op->kt_ival1 = timeval_to_ktime(msg_head->ival1);
  		op->kt_ival2 = timeval_to_ktime(msg_head->ival2);
  
  		/* disable an active timer due to zero values? */
  		if (!op->kt_ival1.tv64 && !op->kt_ival2.tv64)
  			hrtimer_cancel(&op->timer);
  	}
  
  	if (op->flags & STARTTIMER) {
  		hrtimer_cancel(&op->timer);
  		/* spec: send can_frame when starting timer */
  		op->flags |= TX_ANNOUNCE;
  	}
  
  	if (op->flags & TX_ANNOUNCE) {
  		bcm_can_tx(op);
  		if (op->count)
  			op->count--;
  	}
  
  	if (op->flags & STARTTIMER)
  		bcm_tx_start_timer(op);
  
  	return msg_head->nframes * CFSIZ + MHSIZ;
  }
  
  /*
   * bcm_rx_setup - create or update a bcm rx op (for bcm_sendmsg)
   */
  static int bcm_rx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
  			int ifindex, struct sock *sk)
  {
  	struct bcm_sock *bo = bcm_sk(sk);
  	struct bcm_op *op;
  	int do_rx_register;
  	int err = 0;
  
  	if ((msg_head->flags & RX_FILTER_ID) || (!(msg_head->nframes))) {
  		/* be robust against wrong usage ... */
  		msg_head->flags |= RX_FILTER_ID;
  		/* ignore trailing garbage */
  		msg_head->nframes = 0;
  	}
  
  	/* the first element contains the mux-mask => MAX_NFRAMES + 1  */
  	if (msg_head->nframes > MAX_NFRAMES + 1)
  		return -EINVAL;
  
  	if ((msg_head->flags & RX_RTR_FRAME) &&
  	    ((msg_head->nframes != 1) ||
  	     (!(msg_head->can_id & CAN_RTR_FLAG))))
  		return -EINVAL;
  
  	/* check the given can_id */
  	op = bcm_find_op(&bo->rx_ops, msg_head->can_id, ifindex);
  	if (op) {
  		/* update existing BCM operation */
  
  		/*
  		 * Do we need more space for the can_frames than currently
  		 * allocated? -> This is a _really_ unusual use-case and
  		 * therefore (complexity / locking) it is not supported.
  		 */
  		if (msg_head->nframes > op->nframes)
  			return -E2BIG;
  
  		if (msg_head->nframes) {
  			/* update can_frames content */
  			err = memcpy_fromiovec((u8 *)op->frames,
  					       msg->msg_iov,
  					       msg_head->nframes * CFSIZ);
  			if (err < 0)
  				return err;
  
  			/* clear last_frames to indicate 'nothing received' */
  			memset(op->last_frames, 0, msg_head->nframes * CFSIZ);
  		}
  
  		op->nframes = msg_head->nframes;
  
  		/* Only an update -> do not call can_rx_register() */
  		do_rx_register = 0;
  
  	} else {
  		/* insert new BCM operation for the given can_id */
  		op = kzalloc(OPSIZ, GFP_KERNEL);
  		if (!op)
  			return -ENOMEM;
  
  		op->can_id    = msg_head->can_id;
  		op->nframes   = msg_head->nframes;
  
  		if (msg_head->nframes > 1) {
  			/* create array for can_frames and copy the data */
  			op->frames = kmalloc(msg_head->nframes * CFSIZ,
  					     GFP_KERNEL);
  			if (!op->frames) {
  				kfree(op);
  				return -ENOMEM;
  			}
  
  			/* create and init array for received can_frames */
  			op->last_frames = kzalloc(msg_head->nframes * CFSIZ,
  						  GFP_KERNEL);
  			if (!op->last_frames) {
  				kfree(op->frames);
  				kfree(op);
  				return -ENOMEM;
  			}
  
  		} else {
  			op->frames = &op->sframe;
  			op->last_frames = &op->last_sframe;
  		}
  
  		if (msg_head->nframes) {
  			err = memcpy_fromiovec((u8 *)op->frames, msg->msg_iov,
  					       msg_head->nframes * CFSIZ);
  			if (err < 0) {
  				if (op->frames != &op->sframe)
  					kfree(op->frames);
  				if (op->last_frames != &op->last_sframe)
  					kfree(op->last_frames);
  				kfree(op);
  				return err;
  			}
  		}
  
  		/* bcm_can_tx / bcm_tx_timeout_handler needs this */
  		op->sk = sk;
  		op->ifindex = ifindex;
  
  		/* ifindex for timeout events w/o previous frame reception */
  		op->rx_ifindex = ifindex;
  
  		/* initialize uninitialized (kzalloc) structure */
  		hrtimer_init(&op->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
  		op->timer.function = bcm_rx_timeout_handler;
  
  		/* initialize tasklet for rx timeout notification */
  		tasklet_init(&op->tsklet, bcm_rx_timeout_tsklet,
  			     (unsigned long) op);
  
  		hrtimer_init(&op->thrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
  		op->thrtimer.function = bcm_rx_thr_handler;
  
  		/* initialize tasklet for rx throttle handling */
  		tasklet_init(&op->thrtsklet, bcm_rx_thr_tsklet,
  			     (unsigned long) op);
  
  		/* add this bcm_op to the list of the rx_ops */
  		list_add(&op->list, &bo->rx_ops);
  
  		/* call can_rx_register() */
  		do_rx_register = 1;
  
  	} /* if ((op = bcm_find_op(&bo->rx_ops, msg_head->can_id, ifindex))) */
  
  	/* check flags */
  	op->flags = msg_head->flags;
  
  	if (op->flags & RX_RTR_FRAME) {
  
  		/* no timers in RTR-mode */
  		hrtimer_cancel(&op->thrtimer);
  		hrtimer_cancel(&op->timer);
  
  		/*
  		 * funny feature in RX(!)_SETUP only for RTR-mode:
  		 * copy can_id into frame BUT without RTR-flag to
  		 * prevent a full-load-loopback-test ... ;-]
  		 */
  		if ((op->flags & TX_CP_CAN_ID) ||
  		    (op->frames[0].can_id == op->can_id))
  			op->frames[0].can_id = op->can_id & ~CAN_RTR_FLAG;
  
  	} else {
  		if (op->flags & SETTIMER) {
  
  			/* set timer value */
  			op->ival1 = msg_head->ival1;
  			op->ival2 = msg_head->ival2;
  			op->kt_ival1 = timeval_to_ktime(msg_head->ival1);
  			op->kt_ival2 = timeval_to_ktime(msg_head->ival2);
  
  			/* disable an active timer due to zero value? */
  			if (!op->kt_ival1.tv64)
  				hrtimer_cancel(&op->timer);
  
  			/*
  			 * In any case cancel the throttle timer, flush
  			 * potentially blocked msgs and reset throttle handling
  			 */
  			op->kt_lastmsg = ktime_set(0, 0);
  			hrtimer_cancel(&op->thrtimer);
  			bcm_rx_thr_flush(op, 1);
  		}
  
  		if ((op->flags & STARTTIMER) && op->kt_ival1.tv64)
  			hrtimer_start(&op->timer, op->kt_ival1,
  				      HRTIMER_MODE_REL);
  	}
  
  	/* now we can register for can_ids, if we added a new bcm_op */
  	if (do_rx_register) {
  		if (ifindex) {
  			struct net_device *dev;
  
  			dev = dev_get_by_index(&init_net, ifindex);
  			if (dev) {
  				err = can_rx_register(dev, op->can_id,
  						      REGMASK(op->can_id),
  						      bcm_rx_handler, op,
  						      "bcm");
  
  				op->rx_reg_dev = dev;
  				dev_put(dev);
  			}
  
  		} else
  			err = can_rx_register(NULL, op->can_id,
  					      REGMASK(op->can_id),
  					      bcm_rx_handler, op, "bcm");
  		if (err) {
  			/* this bcm rx op is broken -> remove it */
  			list_del(&op->list);
  			bcm_remove_op(op);
  			return err;
  		}
  	}
  
  	return msg_head->nframes * CFSIZ + MHSIZ;
  }
  
  /*
   * bcm_tx_send - send a single CAN frame to the CAN interface (for bcm_sendmsg)
   */
  static int bcm_tx_send(struct msghdr *msg, int ifindex, struct sock *sk)
  {
  	struct sk_buff *skb;
  	struct net_device *dev;
  	int err;
  
  	/* we need a real device to send frames */
  	if (!ifindex)
  		return -ENODEV;
  
  	skb = alloc_skb(CFSIZ + sizeof(struct can_skb_priv), GFP_KERNEL);
  	if (!skb)
  		return -ENOMEM;
  
  	can_skb_reserve(skb);
  
  	err = memcpy_fromiovec(skb_put(skb, CFSIZ), msg->msg_iov, CFSIZ);
  	if (err < 0) {
  		kfree_skb(skb);
  		return err;
  	}
  
  	dev = dev_get_by_index(&init_net, ifindex);
  	if (!dev) {
  		kfree_skb(skb);
  		return -ENODEV;
  	}
  
  	can_skb_prv(skb)->ifindex = dev->ifindex;
  	skb->dev = dev;
  	can_skb_set_owner(skb, sk);
  	err = can_send(skb, 1); /* send with loopback */
  	dev_put(dev);
  
  	if (err)
  		return err;
  
  	return CFSIZ + MHSIZ;
  }
  
  /*
   * bcm_sendmsg - process BCM commands (opcodes) from the userspace
   */
  static int bcm_sendmsg(struct kiocb *iocb, struct socket *sock,
  		       struct msghdr *msg, size_t size)
  {
  	struct sock *sk = sock->sk;
  	struct bcm_sock *bo = bcm_sk(sk);
  	int ifindex = bo->ifindex; /* default ifindex for this bcm_op */
  	struct bcm_msg_head msg_head;
  	int ret; /* read bytes or error codes as return value */
  
  	if (!bo->bound)
  		return -ENOTCONN;
  
  	/* check for valid message length from userspace */
  	if (size < MHSIZ || (size - MHSIZ) % CFSIZ)
  		return -EINVAL;
  
  	/* check for alternative ifindex for this bcm_op */
  
  	if (!ifindex && msg->msg_name) {
  		/* no bound device as default => check msg_name */
  		struct sockaddr_can *addr =
  			(struct sockaddr_can *)msg->msg_name;
  
  		if (msg->msg_namelen < sizeof(*addr))
  			return -EINVAL;
  
  		if (addr->can_family != AF_CAN)
  			return -EINVAL;
  
  		/* ifindex from sendto() */
  		ifindex = addr->can_ifindex;
  
  		if (ifindex) {
  			struct net_device *dev;
  
  			dev = dev_get_by_index(&init_net, ifindex);
  			if (!dev)
  				return -ENODEV;
  
  			if (dev->type != ARPHRD_CAN) {
  				dev_put(dev);
  				return -ENODEV;
  			}
  
  			dev_put(dev);
  		}
  	}
  
  	/* read message head information */
  
  	ret = memcpy_fromiovec((u8 *)&msg_head, msg->msg_iov, MHSIZ);
  	if (ret < 0)
  		return ret;
  
  	lock_sock(sk);
  
  	switch (msg_head.opcode) {
  
  	case TX_SETUP:
  		ret = bcm_tx_setup(&msg_head, msg, ifindex, sk);
  		break;
  
  	case RX_SETUP:
  		ret = bcm_rx_setup(&msg_head, msg, ifindex, sk);
  		break;
  
  	case TX_DELETE:
  		if (bcm_delete_tx_op(&bo->tx_ops, msg_head.can_id, ifindex))
  			ret = MHSIZ;
  		else
  			ret = -EINVAL;
  		break;
  
  	case RX_DELETE:
  		if (bcm_delete_rx_op(&bo->rx_ops, msg_head.can_id, ifindex))
  			ret = MHSIZ;
  		else
  			ret = -EINVAL;
  		break;
  
  	case TX_READ:
  		/* reuse msg_head for the reply to TX_READ */
  		msg_head.opcode  = TX_STATUS;
  		ret = bcm_read_op(&bo->tx_ops, &msg_head, ifindex);
  		break;
  
  	case RX_READ:
  		/* reuse msg_head for the reply to RX_READ */
  		msg_head.opcode  = RX_STATUS;
  		ret = bcm_read_op(&bo->rx_ops, &msg_head, ifindex);
  		break;
  
  	case TX_SEND:
  		/* we need exactly one can_frame behind the msg head */
  		if ((msg_head.nframes != 1) || (size != CFSIZ + MHSIZ))
  			ret = -EINVAL;
  		else
  			ret = bcm_tx_send(msg, ifindex, sk);
  		break;
  
  	default:
  		ret = -EINVAL;
  		break;
  	}
  
  	release_sock(sk);
  
  	return ret;
  }
  
  /*
   * notification handler for netdevice status changes
   */
  static int bcm_notifier(struct notifier_block *nb, unsigned long msg,
  			void *data)
  {
  	struct net_device *dev = (struct net_device *)data;
  	struct bcm_sock *bo = container_of(nb, struct bcm_sock, notifier);
  	struct sock *sk = &bo->sk;
  	struct bcm_op *op;
  	int notify_enodev = 0;
  
  	if (!net_eq(dev_net(dev), &init_net))
  		return NOTIFY_DONE;
  
  	if (dev->type != ARPHRD_CAN)
  		return NOTIFY_DONE;
  
  	switch (msg) {
  
  	case NETDEV_UNREGISTER:
  		lock_sock(sk);
  
  		/* remove device specific receive entries */
  		list_for_each_entry(op, &bo->rx_ops, list)
  			if (op->rx_reg_dev == dev)
  				bcm_rx_unreg(dev, op);
  
  		/* remove device reference, if this is our bound device */
  		if (bo->bound && bo->ifindex == dev->ifindex) {
  			bo->bound   = 0;
  			bo->ifindex = 0;
  			notify_enodev = 1;
  		}
  
  		release_sock(sk);
  
  		if (notify_enodev) {
  			sk->sk_err = ENODEV;
  			if (!sock_flag(sk, SOCK_DEAD))
  				sk->sk_error_report(sk);
  		}
  		break;
  
  	case NETDEV_DOWN:
  		if (bo->bound && bo->ifindex == dev->ifindex) {
  			sk->sk_err = ENETDOWN;
  			if (!sock_flag(sk, SOCK_DEAD))
  				sk->sk_error_report(sk);
  		}
  	}
  
  	return NOTIFY_DONE;
  }
  
  /*
   * initial settings for all BCM sockets to be set at socket creation time
   */
  static int bcm_init(struct sock *sk)
  {
  	struct bcm_sock *bo = bcm_sk(sk);
  
  	bo->bound            = 0;
  	bo->ifindex          = 0;
  	bo->dropped_usr_msgs = 0;
  	bo->bcm_proc_read    = NULL;
  
  	INIT_LIST_HEAD(&bo->tx_ops);
  	INIT_LIST_HEAD(&bo->rx_ops);
  
  	/* set notifier */
  	bo->notifier.notifier_call = bcm_notifier;
  
  	register_netdevice_notifier(&bo->notifier);
  
  	return 0;
  }
  
  /*
   * standard socket functions
   */
  static int bcm_release(struct socket *sock)
  {
  	struct sock *sk = sock->sk;
  	struct bcm_sock *bo;
  	struct bcm_op *op, *next;
  
  	if (sk == NULL)
  		return 0;
  
  	bo = bcm_sk(sk);
  
  	/* remove bcm_ops, timer, rx_unregister(), etc. */
  
  	unregister_netdevice_notifier(&bo->notifier);
  
  	lock_sock(sk);
  
  	list_for_each_entry_safe(op, next, &bo->tx_ops, list)
  		bcm_remove_op(op);
  
  	list_for_each_entry_safe(op, next, &bo->rx_ops, list) {
  		/*
  		 * Don't care if we're bound or not (due to netdev problems)
  		 * can_rx_unregister() is always a save thing to do here.
  		 */
  		if (op->ifindex) {
  			/*
  			 * Only remove subscriptions that had not
  			 * been removed due to NETDEV_UNREGISTER
  			 * in bcm_notifier()
  			 */
  			if (op->rx_reg_dev) {
  				struct net_device *dev;
  
  				dev = dev_get_by_index(&init_net, op->ifindex);
  				if (dev) {
  					bcm_rx_unreg(dev, op);
  					dev_put(dev);
  				}
  			}
  		} else
  			can_rx_unregister(NULL, op->can_id,
  					  REGMASK(op->can_id),
  					  bcm_rx_handler, op);
  
  		bcm_remove_op(op);
  	}
  
  	/* remove procfs entry */
  	if (proc_dir && bo->bcm_proc_read)
  		remove_proc_entry(bo->procname, proc_dir);
  
  	/* remove device reference */
  	if (bo->bound) {
  		bo->bound   = 0;
  		bo->ifindex = 0;
  	}
  
  	sock_orphan(sk);
  	sock->sk = NULL;
  
  	release_sock(sk);
  	sock_put(sk);
  
  	return 0;
  }
  
  static int bcm_connect(struct socket *sock, struct sockaddr *uaddr, int len,
  		       int flags)
  {
  	struct sockaddr_can *addr = (struct sockaddr_can *)uaddr;
  	struct sock *sk = sock->sk;
  	struct bcm_sock *bo = bcm_sk(sk);
  
  	if (len < sizeof(*addr))
  		return -EINVAL;
  
  	if (bo->bound)
  		return -EISCONN;
  
  	/* bind a device to this socket */
  	if (addr->can_ifindex) {
  		struct net_device *dev;
  
  		dev = dev_get_by_index(&init_net, addr->can_ifindex);
  		if (!dev)
  			return -ENODEV;
  
  		if (dev->type != ARPHRD_CAN) {
  			dev_put(dev);
  			return -ENODEV;
  		}
  
  		bo->ifindex = dev->ifindex;
  		dev_put(dev);
  
  	} else {
  		/* no interface reference for ifindex = 0 ('any' CAN device) */
  		bo->ifindex = 0;
  	}
  
  	bo->bound = 1;
  
  	if (proc_dir) {
  		/* unique socket address as filename */
  		sprintf(bo->procname, "%lu", sock_i_ino(sk));
  		bo->bcm_proc_read = proc_create_data(bo->procname, 0644,
  						     proc_dir,
  						     &bcm_proc_fops, sk);
  	}
  
  	return 0;
  }
  
  static int bcm_recvmsg(struct kiocb *iocb, struct socket *sock,
  		       struct msghdr *msg, size_t size, int flags)
  {
  	struct sock *sk = sock->sk;
  	struct sk_buff *skb;
  	int error = 0;
  	int noblock;
  	int err;
  
  	noblock =  flags & MSG_DONTWAIT;
  	flags   &= ~MSG_DONTWAIT;
  	skb = skb_recv_datagram(sk, flags, noblock, &error);
  	if (!skb)
  		return error;
  
  	if (skb->len < size)
  		size = skb->len;
  
  	err = memcpy_toiovec(msg->msg_iov, skb->data, size);
  	if (err < 0) {
  		skb_free_datagram(sk, skb);
  		return err;
  	}
  
  	sock_recv_ts_and_drops(msg, sk, skb);
  
  	if (msg->msg_name) {
  		msg->msg_namelen = sizeof(struct sockaddr_can);
  		memcpy(msg->msg_name, skb->cb, msg->msg_namelen);
  	}
  
  	skb_free_datagram(sk, skb);
  
  	return size;
  }
  
  static const struct proto_ops bcm_ops = {
  	.family        = PF_CAN,
  	.release       = bcm_release,
  	.bind          = sock_no_bind,
  	.connect       = bcm_connect,
  	.socketpair    = sock_no_socketpair,
  	.accept        = sock_no_accept,
  	.getname       = sock_no_getname,
  	.poll          = datagram_poll,
  	.ioctl         = can_ioctl,	/* use can_ioctl() from af_can.c */
  	.listen        = sock_no_listen,
  	.shutdown      = sock_no_shutdown,
  	.setsockopt    = sock_no_setsockopt,
  	.getsockopt    = sock_no_getsockopt,
  	.sendmsg       = bcm_sendmsg,
  	.recvmsg       = bcm_recvmsg,
  	.mmap          = sock_no_mmap,
  	.sendpage      = sock_no_sendpage,
  };
  
  static struct proto bcm_proto __read_mostly = {
  	.name       = "CAN_BCM",
  	.owner      = THIS_MODULE,
  	.obj_size   = sizeof(struct bcm_sock),
  	.init       = bcm_init,
  };
  
  static const struct can_proto bcm_can_proto = {
  	.type       = SOCK_DGRAM,
  	.protocol   = CAN_BCM,
  	.ops        = &bcm_ops,
  	.prot       = &bcm_proto,
  };
  
  static int __init bcm_module_init(void)
  {
  	int err;
  
  	printk(banner);
  
  	err = can_proto_register(&bcm_can_proto);
  	if (err < 0) {
  		printk(KERN_ERR "can: registration of bcm protocol failed\n");
  		return err;
  	}
  
  	/* create /proc/net/can-bcm directory */
  	proc_dir = proc_mkdir("can-bcm", init_net.proc_net);
  	return 0;
  }
  
  static void __exit bcm_module_exit(void)
  {
  	can_proto_unregister(&bcm_can_proto);
  
  	if (proc_dir)
  		remove_proc_entry("can-bcm", init_net.proc_net);
  }
  
  module_init(bcm_module_init);
  module_exit(bcm_module_exit);
  