[CAN]: Add broadcast manager (bcm) protocol

This patch adds the CAN broadcast manager (bcm) protocol.

Signed-off-by: Oliver Hartkopp <[e-mail]>
Signed-off-by: Urs Thuermann <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/linux/can/bcm.h

···
+/*
+ * linux/can/bcm.h
+ *
+ * Definitions for CAN Broadcast Manager (BCM)
+ *
+ * Author: Oliver Hartkopp <[e-mail]>
+ * Copyright (c) 2002-2007 Volkswagen Group Electronic Research
+ * All rights reserved.
+ *
+ * Send feedback to <[e-mail]>
+ *
+ */
+
+#ifndef CAN_BCM_H
+#define CAN_BCM_H
+
+/**
+ * struct bcm_msg_head - head of messages to/from the broadcast manager
+ * @opcode:    opcode, see enum below.
+ * @flags:     special flags, see below.
+ * @count:     number of frames to send before changing interval.
+ * @ival1:     interval for the first @count frames.
+ * @ival2:     interval for the following frames.
+ * @can_id:    CAN ID of frames to be sent or received.
+ * @nframes:   number of frames appended to the message head.
+ * @frames:    array of CAN frames.
+ */
+struct bcm_msg_head {
+	int opcode;
+	int flags;
+	int count;
+	struct timeval ival1, ival2;
+	canid_t can_id;
+	int nframes;
+	struct can_frame frames[0];
+};
+
+enum {
+	TX_SETUP = 1,	/* create (cyclic) transmission task */
+	TX_DELETE,	/* remove (cyclic) transmission task */
+	TX_READ,	/* read properties of (cyclic) transmission task */
+	TX_SEND,	/* send one CAN frame */
+	RX_SETUP,	/* create RX content filter subscription */
+	RX_DELETE,	/* remove RX content filter subscription */
+	RX_READ,	/* read properties of RX content filter subscription */
+	TX_STATUS,	/* reply to TX_READ request */
+	TX_EXPIRED,	/* notification on performed transmissions (count=0) */
+	RX_STATUS,	/* reply to RX_READ request */
+	RX_TIMEOUT,	/* cyclic message is absent */
+	RX_CHANGED	/* updated CAN frame (detected content change) */
+};
+
+#define SETTIMER            0x0001
+#define STARTTIMER          0x0002
+#define TX_COUNTEVT         0x0004
+#define TX_ANNOUNCE         0x0008
+#define TX_CP_CAN_ID        0x0010
+#define RX_FILTER_ID        0x0020
+#define RX_CHECK_DLC        0x0040
+#define RX_NO_AUTOTIMER     0x0080
+#define RX_ANNOUNCE_RESUME  0x0100
+#define TX_RESET_MULTI_IDX  0x0200
+#define RX_RTR_FRAME        0x0400
+
+#endif /* CAN_BCM_H */

net/can/Kconfig

···
 	  most cases where no higher level protocol is being used. The raw
 	  socket has several filter options e.g. ID masking / error frames.
 	  To receive/send raw CAN messages, use AF_CAN with protocol CAN_RAW.
+
+config CAN_BCM
+	tristate "Broadcast Manager CAN Protocol (with content filtering)"
+	depends on CAN
+	default N
+	---help---
+	  The Broadcast Manager offers content filtering, timeout monitoring,
+	  sending of RTR frames, and cyclic CAN messages without permanent user
+	  interaction. The BCM can be 'programmed' via the BSD socket API and
+	  informs you on demand e.g. only on content updates / timeouts.
+	  You probably want to use the bcm socket in most cases where cyclic
+	  CAN messages are used on the bus (e.g. in automotive environments).
+	  To use the Broadcast Manager, use AF_CAN with protocol CAN_BCM.

net/can/Makefile

···
 
 obj-$(CONFIG_CAN_RAW)	+= can-raw.o
 can-raw-objs		:= raw.o
+
+obj-$(CONFIG_CAN_BCM)	+= can-bcm.o
+can-bcm-objs		:= bcm.o

net/can/bcm.c

···
+/*
+ * 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.
+ *
+ * Send feedback to <[e-mail]>
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/proc_fs.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/bcm.h>
+#include <net/sock.h>
+#include <net/net_namespace.h>
+
+/* 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_RTR_FLAG) | ((id & CAN_EFF_FLAG) ? \
+			(CAN_EFF_MASK | CAN_EFF_FLAG) : CAN_SFF_MASK))
+
+#define CAN_BCM_VERSION CAN_VERSION
+static __initdata const char banner[] = KERN_INFO
+	"can: broadcast manager protocol (rev " CAN_BCM_VERSION ")\n";
+
+MODULE_DESCRIPTION("PF_CAN broadcast manager protocol");
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_AUTHOR("Oliver Hartkopp <[e-mail]>");
+
+/* 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;
+	int flags;
+	unsigned long j_ival1, j_ival2, j_lastmsg;
+	unsigned long frames_abs, frames_filtered;
+	struct timer_list timer, thrtimer;
+	struct timeval ival1, ival2;
+	ktime_t rx_stamp;
+	int rx_ifindex;
+	int count;
+	int nframes;
+	int 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 [9]; /* pointer printed in ASCII 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)
+
+/*
+ * rounded_tv2jif - calculate jiffies from timeval including optional up
+ * @tv: pointer to timeval
+ *
+ * Description:
+ * Unlike timeval_to_jiffies() provided in include/linux/jiffies.h, this
+ * function is intentionally more relaxed on precise timer ticks to get
+ * exact one jiffy for requested 1000us on a 1000HZ machine.
+ * This code is to be removed when upgrading to kernel hrtimer.
+ *
+ * Return:
+ *  calculated jiffies (max: ULONG_MAX)
+ */
+static unsigned long rounded_tv2jif(const struct timeval *tv)
+{
+	unsigned long sec  = tv->tv_sec;
+	unsigned long usec = tv->tv_usec;
+	unsigned long jif;
+
+	if (sec > ULONG_MAX / HZ)
+		return ULONG_MAX;
+
+	/* round up to get at least the requested time */
+	usec += 1000000 / HZ - 1;
+
+	jif  = usec / (1000000 / HZ);
+
+	if (sec * HZ > ULONG_MAX - jif)
+		return ULONG_MAX;
+
+	return jif + sec * HZ;
+}
+
+/*
+ * procfs functions
+ */
+static char *bcm_proc_getifname(int ifindex)
+{
+	struct net_device *dev;
+
+	if (!ifindex)
+		return "any";
+
+	/* no usage counting */
+	dev = __dev_get_by_index(&init_net, ifindex);
+	if (dev)
+		return dev->name;
+
+	return "???";
+}
+
+static int bcm_read_proc(char *page, char **start, off_t off,
+			 int count, int *eof, void *data)
+{
+	int len = 0;
+	struct sock *sk = (struct sock *)data;
+	struct bcm_sock *bo = bcm_sk(sk);
+	struct bcm_op *op;
+
+	len += snprintf(page + len, PAGE_SIZE - len, ">>> socket %p",
+			sk->sk_socket);
+	len += snprintf(page + len, PAGE_SIZE - len, " / sk %p", sk);
+	len += snprintf(page + len, PAGE_SIZE - len, " / bo %p", bo);
+	len += snprintf(page + len, PAGE_SIZE - len, " / dropped %lu",
+			bo->dropped_usr_msgs);
+	len += snprintf(page + len, PAGE_SIZE - len, " / bound %s",
+			bcm_proc_getifname(bo->ifindex));
+	len += snprintf(page + len, PAGE_SIZE - len, " <<<\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;
+
+		len += snprintf(page + len, PAGE_SIZE - len,
+				"rx_op: %03X %-5s ",
+				op->can_id, bcm_proc_getifname(op->ifindex));
+		len += snprintf(page + len, PAGE_SIZE - len, "[%d]%c ",
+				op->nframes,
+				(op->flags & RX_CHECK_DLC)?'d':' ');
+		if (op->j_ival1)
+			len += snprintf(page + len, PAGE_SIZE - len,
+					"timeo=%ld ", op->j_ival1);
+
+		if (op->j_ival2)
+			len += snprintf(page + len, PAGE_SIZE - len,
+					"thr=%ld ", op->j_ival2);
+
+		len += snprintf(page + len, PAGE_SIZE - len,
+				"# recv %ld (%ld) => reduction: ",
+				op->frames_filtered, op->frames_abs);
+
+		reduction = 100 - (op->frames_filtered * 100) / op->frames_abs;
+
+		len += snprintf(page + len, PAGE_SIZE - len, "%s%ld%%\n",
+				(reduction == 100)?"near ":"", reduction);
+
+		if (len > PAGE_SIZE - 200) {
+			/* mark output cut off */
+			len += snprintf(page + len, PAGE_SIZE - len, "(..)\n");
+			break;
+		}
+	}
+
+	list_for_each_entry(op, &bo->tx_ops, list) {
+
+		len += snprintf(page + len, PAGE_SIZE - len,
+				"tx_op: %03X %s [%d] ",
+				op->can_id, bcm_proc_getifname(op->ifindex),
+				op->nframes);
+		if (op->j_ival1)
+			len += snprintf(page + len, PAGE_SIZE - len, "t1=%ld ",
+					op->j_ival1);
+
+		if (op->j_ival2)
+			len += snprintf(page + len, PAGE_SIZE - len, "t2=%ld ",
+					op->j_ival2);
+
+		len += snprintf(page + len, PAGE_SIZE - len, "# sent %ld\n",
+				op->frames_abs);
+
+		if (len > PAGE_SIZE - 100) {
+			/* mark output cut off */
+			len += snprintf(page + len, PAGE_SIZE - len, "(..)\n");
+			break;
+		}
+	}
+
+	len += snprintf(page + len, PAGE_SIZE - len, "\n");
+
+	*eof = 1;
+	return len;
+}
+
+/*
+ * 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, gfp_any());
+	if (!skb)
+		goto out;
+
+	memcpy(skb_put(skb, CFSIZ), cf, CFSIZ);
+
+	/* send with loopback */
+	skb->dev = dev;
+	skb->sk = 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;
+	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++;
+	}
+}
+
+/*
+ * bcm_tx_timeout_handler - performes cyclic CAN frame transmissions
+ */
+static void bcm_tx_timeout_handler(unsigned long data)
+{
+	struct bcm_op *op = (struct bcm_op *)data;
+
+	if (op->j_ival1 && (op->count > 0)) {
+
+		op->count--;
+		if (!op->count && (op->flags & TX_COUNTEVT)) {
+			struct bcm_msg_head msg_head;
+
+			/* 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);
+		}
+	}
+
+	if (op->j_ival1 && (op->count > 0)) {
+
+		/* send (next) frame */
+		bcm_can_tx(op);
+		mod_timer(&op->timer, jiffies + op->j_ival1);
+
+	} else {
+		if (op->j_ival2) {
+
+			/* send (next) frame */
+			bcm_can_tx(op);
+			mod_timer(&op->timer, jiffies + op->j_ival2);
+		}
+	}
+
+	return;
+}
+
+/*
+ * 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;
+
+	op->j_lastmsg = jiffies;
+
+	/* update statistics */
+	op->frames_filtered++;
+
+	/* prevent statistics overflow */
+	if (op->frames_filtered > ULONG_MAX/100)
+		op->frames_filtered = op->frames_abs = 0;
+
+	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,
+				   struct can_frame *rxdata)
+{
+	unsigned long nexttx = op->j_lastmsg + op->j_ival2;
+
+	memcpy(lastdata, rxdata, CFSIZ);
+
+	/* mark as used */
+	lastdata->can_dlc |= RX_RECV;
+
+	/* throttle bcm_rx_changed ? */
+	if ((op->thrtimer.expires) ||
+	    ((op->j_ival2) && (nexttx > jiffies))) {
+		/* we are already waiting OR we have to start waiting */
+
+		/* mark as 'throttled' */
+		lastdata->can_dlc |= RX_THR;
+
+		if (!(op->thrtimer.expires)) {
+			/* start the timer only the first time */
+			mod_timer(&op->thrtimer, nexttx);
+		}
+
+	} else {
+		/* send RX_CHANGED to the user immediately */
+		bcm_rx_changed(op, rxdata);
+	}
+}
+
+/*
+ * 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, int index,
+				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->j_ival1)
+		mod_timer(&op->timer, jiffies + op->j_ival1);
+}
+
+/*
+ * bcm_rx_timeout_handler - when the (cyclic) CAN frame receiption timed out
+ */
+static void bcm_rx_timeout_handler(unsigned long data)
+{
+	struct bcm_op *op = (struct bcm_op *)data;
+	struct bcm_msg_head msg_head;
+
+	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);
+
+	/* 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);
+	}
+}
+
+/*
+ * bcm_rx_thr_handler - the time for blocked content updates is over now:
+ *                      Check for throttled data and send it to the userspace
+ */
+static void bcm_rx_thr_handler(unsigned long data)
+{
+	struct bcm_op *op = (struct bcm_op *)data;
+	int i = 0;
+
+	/* mark disabled / consumed timer */
+	op->thrtimer.expires = 0;
+
+	if (op->nframes > 1) {
+		/* for MUX filter we start at index 1 */
+		for (i = 1; i < op->nframes; i++) {
+			if ((op->last_frames) &&
+			    (op->last_frames[i].can_dlc & RX_THR)) {
+				op->last_frames[i].can_dlc &= ~RX_THR;
+				bcm_rx_changed(op, &op->last_frames[i]);
+			}
+		}
+
+	} else {
+		/* for RX_FILTER_ID and simple filter */
+		if (op->last_frames && (op->last_frames[0].can_dlc & RX_THR)) {
+			op->last_frames[0].can_dlc &= ~RX_THR;
+			bcm_rx_changed(op, &op->last_frames[0]);
+		}
+	}
+}
+
+/*
+ * 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;
+	struct can_frame rxframe;
+	int i;
+
+	/* disable timeout */
+	del_timer(&op->timer);
+
+	if (skb->len == sizeof(rxframe)) {
+		memcpy(&rxframe, skb->data, sizeof(rxframe));
+		/* save rx timestamp */
+		op->rx_stamp = skb->tstamp;
+		/* save originator for recvfrom() */
+		op->rx_ifindex = skb->dev->ifindex;
+		/* update statistics */
+		op->frames_abs++;
+		kfree_skb(skb);
+
+	} else {
+		kfree_skb(skb);
+		return;
+	}
+
+	if (op->can_id != rxframe.can_id)
+		return;
+
+	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);
+		bcm_rx_starttimer(op);
+		return;
+	}
+
+	if (op->nframes == 1) {
+		/* simple compare with index 0 */
+		bcm_rx_cmp_to_index(op, 0, &rxframe);
+		bcm_rx_starttimer(op);
+		return;
+	}
+
+	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;
+			}
+		}
+		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)
+{
+	del_timer(&op->timer);
+	del_timer(&op->thrtimer);
+
+	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);
+
+	return;
+}
+
+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;
+	int i, err;
+
+	/* we need a real device to send frames */
+	if (!ifindex)
+		return -ENODEV;
+
+	/* we need at least one can_frame */
+	if (msg_head->nframes < 1)
+		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 (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 (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 */
+		setup_timer(&op->timer, bcm_tx_timeout_handler,
+			    (unsigned long)op);
+
+		/* currently unused in tx_ops */
+		init_timer(&op->thrtimer);
+
+		/* 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->j_ival1 = rounded_tv2jif(&msg_head->ival1);
+		op->j_ival2 = rounded_tv2jif(&msg_head->ival2);
+
+		/* disable an active timer due to zero values? */
+		if (!op->j_ival1 && !op->j_ival2)
+			del_timer(&op->timer);
+	}
+
+	if ((op->flags & STARTTIMER) &&
+	    ((op->j_ival1 && op->count) || op->j_ival2)) {
+
+		/* spec: send can_frame when starting timer */
+		op->flags |= TX_ANNOUNCE;
+
+		if (op->j_ival1 && (op->count > 0)) {
+			/* op->count-- is done in bcm_tx_timeout_handler */
+			mod_timer(&op->timer, jiffies + op->j_ival1);
+		} else
+			mod_timer(&op->timer, jiffies + op->j_ival2);
+	}
+
+	if (op->flags & TX_ANNOUNCE)
+		bcm_can_tx(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;
+	}
+
+	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;
+
+		/* initialize uninitialized (kzalloc) structure */
+		setup_timer(&op->timer, bcm_rx_timeout_handler,
+			    (unsigned long)op);
+
+		/* init throttle timer for RX_CHANGED */
+		setup_timer(&op->thrtimer, bcm_rx_thr_handler,
+			    (unsigned long)op);
+
+		/* mark disabled timer */
+		op->thrtimer.expires = 0;
+
+		/* 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 */
+		del_timer(&op->thrtimer);
+		del_timer(&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->j_ival1 = rounded_tv2jif(&msg_head->ival1);
+			op->j_ival2 = rounded_tv2jif(&msg_head->ival2);
+
+			/* disable an active timer due to zero value? */
+			if (!op->j_ival1)
+				del_timer(&op->timer);
+
+			/* free currently blocked msgs ? */
+			if (op->thrtimer.expires) {
+				/* send blocked msgs hereafter */
+				mod_timer(&op->thrtimer, jiffies + 2);
+			}
+
+			/*
+			 * if (op->j_ival2) is zero, no (new) throttling
+			 * will happen. For details see functions
+			 * bcm_rx_update_and_send() and bcm_rx_thr_handler()
+			 */
+		}
+
+		if ((op->flags & STARTTIMER) && op->j_ival1)
+			mod_timer(&op->timer, jiffies + op->j_ival1);
+	}
+
+	/* 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, GFP_KERNEL);
+
+	if (!skb)
+		return -ENOMEM;
+
+	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;
+	}
+
+	skb->dev = dev;
+	skb->sk  = sk;
+	can_send(skb, 1); /* send with loopback */
+	dev_put(dev);
+
+	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 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 (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 at least one can_frame */
+		if (msg_head.nframes < 1)
+			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 (dev->nd_net != &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 = bcm_sk(sk);
+	struct bcm_op *op, *next;
+
+	/* 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;
+	}
+
+	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 (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, "%p", sock);
+		bo->bcm_proc_read = create_proc_read_entry(bo->procname, 0644,
+							   proc_dir,
+							   bcm_read_proc, 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_timestamp(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 struct proto_ops bcm_ops __read_mostly = {
+	.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         = NULL,		/* 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 struct can_proto bcm_can_proto __read_mostly = {
+	.type       = SOCK_DGRAM,
+	.protocol   = CAN_BCM,
+	.capability = -1,
+	.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);
+
+	if (proc_dir)
+		proc_dir->owner = THIS_MODULE;
+
+	return 0;
+}
+
+static void __exit bcm_module_exit(void)
+{
+	can_proto_unregister(&bcm_can_proto);
+
+	if (proc_dir)
+		proc_net_remove(&init_net, "can-bcm");
+}
+
+module_init(bcm_module_init);
+module_exit(bcm_module_exit);