Adding upstream version 5.10.209.upstream/5.10.209

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1774 insertions, 0 deletions

diff --git a/net/can/bcm.c b/net/can/bcm.c
new file mode 100644
index 000000000..2388c619f
--- /dev/null
+++ b/net/can/bcm.c
@@ -0,0 +1,1774 @@
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+/*
+ * bcm.c - Broadcast Manager to filter/send (cyclic) CAN content
+ *
+ * Copyright (c) 2002-2017 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
+
+/* limit timers to 400 days for sending/timeouts */
+#define BCM_TIMER_SEC_MAX (400 * 24 * 60 * 60)
+
+/* use of last_frames[index].flags */
+#define RX_RECV    0x40 /* received data for this element */
+#define RX_THR     0x80 /* element not been sent due to throttle feature */
+#define BCM_CAN_FLAGS_MASK 0x3F /* to clean private flags after usage */
+
+/* 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))
+
+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");
+
+#define BCM_MIN_NAMELEN CAN_REQUIRED_SIZE(struct sockaddr_can, can_ifindex)
+
+/*
+ * easy access to the first 64 bit of can(fd)_frame payload. cp->data is
+ * 64 bit aligned so the offset has to be multiples of 8 which is ensured
+ * by the only callers in bcm_rx_cmp_to_index() bcm_rx_handler().
+ */
+static inline u64 get_u64(const struct canfd_frame *cp, int offset)
+{
+	return *(u64 *)(cp->data + offset);
+}
+
+struct bcm_op {
+	struct list_head list;
+	struct rcu_head rcu;
+	int ifindex;
+	canid_t can_id;
+	u32 flags;
+	unsigned long frames_abs, frames_filtered;
+	struct bcm_timeval ival1, ival2;
+	struct hrtimer timer, thrtimer;
+	ktime_t rx_stamp, kt_ival1, kt_ival2, kt_lastmsg;
+	int rx_ifindex;
+	int cfsiz;
+	u32 count;
+	u32 nframes;
+	u32 currframe;
+	/* void pointers to arrays of struct can[fd]_frame */
+	void *frames;
+	void *last_frames;
+	struct canfd_frame sframe;
+	struct canfd_frame last_sframe;
+	struct sock *sk;
+	struct net_device *rx_reg_dev;
+};
+
+struct bcm_sock {
+	struct sock sk;
+	int bound;
+	int ifindex;
+	struct list_head 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 LIST_HEAD(bcm_notifier_list);
+static DEFINE_SPINLOCK(bcm_notifier_lock);
+static struct bcm_sock *bcm_busy_notifier;
+
+static inline struct bcm_sock *bcm_sk(const struct sock *sk)
+{
+	return (struct bcm_sock *)sk;
+}
+
+static inline ktime_t bcm_timeval_to_ktime(struct bcm_timeval tv)
+{
+	return ktime_set(tv.tv_sec, tv.tv_usec * NSEC_PER_USEC);
+}
+
+/* check limitations for timeval provided by user */
+static bool bcm_is_invalid_tv(struct bcm_msg_head *msg_head)
+{
+	if ((msg_head->ival1.tv_sec < 0) ||
+	    (msg_head->ival1.tv_sec > BCM_TIMER_SEC_MAX) ||
+	    (msg_head->ival1.tv_usec < 0) ||
+	    (msg_head->ival1.tv_usec >= USEC_PER_SEC) ||
+	    (msg_head->ival2.tv_sec < 0) ||
+	    (msg_head->ival2.tv_sec > BCM_TIMER_SEC_MAX) ||
+	    (msg_head->ival2.tv_usec < 0) ||
+	    (msg_head->ival2.tv_usec >= USEC_PER_SEC))
+		return true;
+
+	return false;
+}
+
+#define CFSIZ(flags) ((flags & CAN_FD_FRAME) ? CANFD_MTU : CAN_MTU)
+#define OPSIZ sizeof(struct bcm_op)
+#define MHSIZ sizeof(struct bcm_msg_head)
+
+/*
+ * procfs functions
+ */
+#if IS_ENABLED(CONFIG_PROC_FS)
+static char *bcm_proc_getifname(struct net *net, char *result, int ifindex)
+{
+	struct net_device *dev;
+
+	if (!ifindex)
+		return "any";
+
+	rcu_read_lock();
+	dev = dev_get_by_index_rcu(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 net *net = m->private;
+	struct sock *sk = (struct sock *)PDE_DATA(m->file->f_inode);
+	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(net, 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(net, ifname, op->ifindex));
+
+		if (op->flags & CAN_FD_FRAME)
+			seq_printf(m, "(%u)", op->nframes);
+		else
+			seq_printf(m, "[%u]", op->nframes);
+
+		seq_printf(m, "%c ", (op->flags & RX_CHECK_DLC) ? 'd' : ' ');
+
+		if (op->kt_ival1)
+			seq_printf(m, "timeo=%lld ",
+				   (long long)ktime_to_us(op->kt_ival1));
+
+		if (op->kt_ival2)
+			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 ", op->can_id,
+			   bcm_proc_getifname(net, ifname, op->ifindex));
+
+		if (op->flags & CAN_FD_FRAME)
+			seq_printf(m, "(%u) ", op->nframes);
+		else
+			seq_printf(m, "[%u] ", op->nframes);
+
+		if (op->kt_ival1)
+			seq_printf(m, "t1=%lld ",
+				   (long long)ktime_to_us(op->kt_ival1));
+
+		if (op->kt_ival2)
+			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;
+}
+#endif /* CONFIG_PROC_FS */
+
+/*
+ * 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 canfd_frame *cf = op->frames + op->cfsiz * op->currframe;
+	int err;
+
+	/* no target device? => exit */
+	if (!op->ifindex)
+		return;
+
+	dev = dev_get_by_index(sock_net(op->sk), op->ifindex);
+	if (!dev) {
+		/* RFC: should this bcm_op remove itself here? */
+		return;
+	}
+
+	skb = alloc_skb(op->cfsiz + sizeof(struct can_skb_priv), gfp_any());
+	if (!skb)
+		goto out;
+
+	can_skb_reserve(skb);
+	can_skb_prv(skb)->ifindex = dev->ifindex;
+	can_skb_prv(skb)->skbcnt = 0;
+
+	skb_put_data(skb, cf, op->cfsiz);
+
+	/* send with loopback */
+	skb->dev = dev;
+	can_skb_set_owner(skb, op->sk);
+	err = can_send(skb, 1);
+	if (!err)
+		op->frames_abs++;
+
+	op->currframe++;
+
+	/* 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 canfd_frame *frames, int has_timestamp)
+{
+	struct sk_buff *skb;
+	struct canfd_frame *firstframe;
+	struct sockaddr_can *addr;
+	struct sock *sk = op->sk;
+	unsigned int datalen = head->nframes * op->cfsiz;
+	int err;
+
+	skb = alloc_skb(sizeof(*head) + datalen, gfp_any());
+	if (!skb)
+		return;
+
+	skb_put_data(skb, head, sizeof(*head));
+
+	if (head->nframes) {
+		/* CAN frames starting here */
+		firstframe = (struct canfd_frame *)skb_tail_pointer(skb);
+
+		skb_put_data(skb, frames, datalen);
+
+		/*
+		 * the BCM uses the flags-element of the canfd_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->flags &= BCM_CAN_FLAGS_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.
+	 */
+
+	sock_skb_cb_check_size(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 bool bcm_tx_set_expiry(struct bcm_op *op, struct hrtimer *hrt)
+{
+	ktime_t ival;
+
+	if (op->kt_ival1 && op->count)
+		ival = op->kt_ival1;
+	else if (op->kt_ival2)
+		ival = op->kt_ival2;
+	else
+		return false;
+
+	hrtimer_set_expires(hrt, ktime_add(ktime_get(), ival));
+	return true;
+}
+
+static void bcm_tx_start_timer(struct bcm_op *op)
+{
+	if (bcm_tx_set_expiry(op, &op->timer))
+		hrtimer_start_expires(&op->timer, HRTIMER_MODE_ABS_SOFT);
+}
+
+/* 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);
+	struct bcm_msg_head msg_head;
+
+	if (op->kt_ival1 && (op->count > 0)) {
+		op->count--;
+		if (!op->count && (op->flags & TX_COUNTEVT)) {
+
+			/* create notification to user */
+			memset(&msg_head, 0, sizeof(msg_head));
+			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) {
+		bcm_can_tx(op);
+	}
+
+	return bcm_tx_set_expiry(op, &op->timer) ?
+		HRTIMER_RESTART : HRTIMER_NORESTART;
+}
+
+/*
+ * bcm_rx_changed - create a RX_CHANGED notification due to changed content
+ */
+static void bcm_rx_changed(struct bcm_op *op, struct canfd_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->flags &= (BCM_CAN_FLAGS_MASK|RX_RECV);
+
+	memset(&head, 0, sizeof(head));
+	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 canfd_frame *lastdata,
+				   const struct canfd_frame *rxdata)
+{
+	memcpy(lastdata, rxdata, op->cfsiz);
+
+	/* mark as used and throttled by default */
+	lastdata->flags |= (RX_RECV|RX_THR);
+
+	/* throttling mode inactive ? */
+	if (!op->kt_ival2) {
+		/* 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 reception with enabled throttling mode */
+	if (!op->kt_lastmsg)
+		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_SOFT);
+		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 canfd_frame *rxdata)
+{
+	struct canfd_frame *cf = op->frames + op->cfsiz * index;
+	struct canfd_frame *lcf = op->last_frames + op->cfsiz * index;
+	int i;
+
+	/*
+	 * no one uses the MSBs of flags for comparison,
+	 * so we use it here to detect the first time of reception
+	 */
+
+	if (!(lcf->flags & RX_RECV)) {
+		/* received data for the first time => send update to user */
+		bcm_rx_update_and_send(op, lcf, rxdata);
+		return;
+	}
+
+	/* do a real check in CAN frame data section */
+	for (i = 0; i < rxdata->len; i += 8) {
+		if ((get_u64(cf, i) & get_u64(rxdata, i)) !=
+		    (get_u64(cf, i) & get_u64(lcf, i))) {
+			bcm_rx_update_and_send(op, lcf, rxdata);
+			return;
+		}
+	}
+
+	if (op->flags & RX_CHECK_DLC) {
+		/* do a real check in CAN frame length */
+		if (rxdata->len != lcf->len) {
+			bcm_rx_update_and_send(op, lcf, rxdata);
+			return;
+		}
+	}
+}
+
+/*
+ * bcm_rx_starttimer - enable timeout monitoring for CAN frame reception
+ */
+static void bcm_rx_starttimer(struct bcm_op *op)
+{
+	if (op->flags & RX_NO_AUTOTIMER)
+		return;
+
+	if (op->kt_ival1)
+		hrtimer_start(&op->timer, op->kt_ival1, HRTIMER_MODE_REL_SOFT);
+}
+
+/* bcm_rx_timeout_handler - when the (cyclic) CAN frame reception timed out */
+static enum hrtimer_restart bcm_rx_timeout_handler(struct hrtimer *hrtimer)
+{
+	struct bcm_op *op = container_of(hrtimer, struct bcm_op, timer);
+	struct bcm_msg_head msg_head;
+
+	/* 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 * op->cfsiz);
+	}
+
+	/* create notification to user */
+	memset(&msg_head, 0, sizeof(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);
+
+	return HRTIMER_NORESTART;
+}
+
+/*
+ * bcm_rx_do_flush - helper for bcm_rx_thr_flush
+ */
+static inline int bcm_rx_do_flush(struct bcm_op *op, unsigned int index)
+{
+	struct canfd_frame *lcf = op->last_frames + op->cfsiz * index;
+
+	if ((op->last_frames) && (lcf->flags & RX_THR)) {
+		bcm_rx_changed(op, lcf);
+		return 1;
+	}
+	return 0;
+}
+
+/*
+ * bcm_rx_thr_flush - Check for throttled data and send it to the userspace
+ */
+static int bcm_rx_thr_flush(struct bcm_op *op)
+{
+	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, i);
+
+	} else {
+		/* for RX_FILTER_ID and simple filter */
+		updated += bcm_rx_do_flush(op, 0);
+	}
+
+	return updated;
+}
+
+/*
+ * 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);
+
+	if (bcm_rx_thr_flush(op)) {
+		hrtimer_forward(hrtimer, ktime_get(), op->kt_ival2);
+		return HRTIMER_RESTART;
+	} else {
+		/* rearm throttle handling */
+		op->kt_lastmsg = 0;
+		return HRTIMER_NORESTART;
+	}
+}
+
+/*
+ * bcm_rx_handler - handle a CAN frame reception
+ */
+static void bcm_rx_handler(struct sk_buff *skb, void *data)
+{
+	struct bcm_op *op = (struct bcm_op *)data;
+	const struct canfd_frame *rxframe = (struct canfd_frame *)skb->data;
+	unsigned int i;
+
+	if (op->can_id != rxframe->can_id)
+		return;
+
+	/* make sure to handle the correct frame type (CAN / CAN FD) */
+	if (skb->len != op->cfsiz)
+		return;
+
+	/* disable timeout */
+	hrtimer_cancel(&op->timer);
+
+	/* 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, 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 - but only the
+		 * first 64 bits of the frame data[] are relevant (CAN FD)
+		 */
+
+		for (i = 1; i < op->nframes; i++) {
+			if ((get_u64(op->frames, 0) & get_u64(rxframe, 0)) ==
+			    (get_u64(op->frames, 0) &
+			     get_u64(op->frames + op->cfsiz * i, 0))) {
+				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,
+				  struct bcm_msg_head *mh, int ifindex)
+{
+	struct bcm_op *op;
+
+	list_for_each_entry(op, ops, list) {
+		if ((op->can_id == mh->can_id) && (op->ifindex == ifindex) &&
+		    (op->flags & CAN_FD_FRAME) == (mh->flags & CAN_FD_FRAME))
+			return op;
+	}
+
+	return NULL;
+}
+
+static void bcm_free_op_rcu(struct rcu_head *rcu_head)
+{
+	struct bcm_op *op = container_of(rcu_head, struct bcm_op, rcu);
+
+	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_remove_op(struct bcm_op *op)
+{
+	hrtimer_cancel(&op->timer);
+	hrtimer_cancel(&op->thrtimer);
+
+	call_rcu(&op->rcu, bcm_free_op_rcu);
+}
+
+static void bcm_rx_unreg(struct net_device *dev, struct bcm_op *op)
+{
+	if (op->rx_reg_dev == dev) {
+		can_rx_unregister(dev_net(dev), 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, struct bcm_msg_head *mh,
+			    int ifindex)
+{
+	struct bcm_op *op, *n;
+
+	list_for_each_entry_safe(op, n, ops, list) {
+		if ((op->can_id == mh->can_id) && (op->ifindex == ifindex) &&
+		    (op->flags & CAN_FD_FRAME) == (mh->flags & CAN_FD_FRAME)) {
+
+			/* disable automatic timer on frame reception */
+			op->flags |= RX_NO_AUTOTIMER;
+
+			/*
+			 * 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(sock_net(op->sk),
+							       op->ifindex);
+					if (dev) {
+						bcm_rx_unreg(dev, op);
+						dev_put(dev);
+					}
+				}
+			} else
+				can_rx_unregister(sock_net(op->sk), 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, struct bcm_msg_head *mh,
+			    int ifindex)
+{
+	struct bcm_op *op, *n;
+
+	list_for_each_entry_safe(op, n, ops, list) {
+		if ((op->can_id == mh->can_id) && (op->ifindex == ifindex) &&
+		    (op->flags & CAN_FD_FRAME) == (mh->flags & CAN_FD_FRAME)) {
+			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, 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;
+	struct canfd_frame *cf;
+	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 timeval limitations */
+	if ((msg_head->flags & SETTIMER) && bcm_is_invalid_tv(msg_head))
+		return -EINVAL;
+
+	/* check the given can_id */
+	op = bcm_find_op(&bo->tx_ops, msg_head, 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++) {
+
+			cf = op->frames + op->cfsiz * i;
+			err = memcpy_from_msg((u8 *)cf, msg, op->cfsiz);
+
+			if (op->flags & CAN_FD_FRAME) {
+				if (cf->len > 64)
+					err = -EINVAL;
+			} else {
+				if (cf->len > 8)
+					err = -EINVAL;
+			}
+
+			if (err < 0)
+				return err;
+
+			if (msg_head->flags & TX_CP_CAN_ID) {
+				/* copy can_id into frame */
+				cf->can_id = msg_head->can_id;
+			}
+		}
+		op->flags = msg_head->flags;
+
+	} 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->cfsiz = CFSIZ(msg_head->flags);
+		op->flags = msg_head->flags;
+
+		/* create array for CAN frames and copy the data */
+		if (msg_head->nframes > 1) {
+			op->frames = kmalloc_array(msg_head->nframes,
+						   op->cfsiz,
+						   GFP_KERNEL);
+			if (!op->frames) {
+				kfree(op);
+				return -ENOMEM;
+			}
+		} else
+			op->frames = &op->sframe;
+
+		for (i = 0; i < msg_head->nframes; i++) {
+
+			cf = op->frames + op->cfsiz * i;
+			err = memcpy_from_msg((u8 *)cf, msg, op->cfsiz);
+			if (err < 0)
+				goto free_op;
+
+			if (op->flags & CAN_FD_FRAME) {
+				if (cf->len > 64)
+					err = -EINVAL;
+			} else {
+				if (cf->len > 8)
+					err = -EINVAL;
+			}
+
+			if (err < 0)
+				goto free_op;
+
+			if (msg_head->flags & TX_CP_CAN_ID) {
+				/* copy can_id into frame */
+				cf->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_SOFT);
+		op->timer.function = bcm_tx_timeout_handler;
+
+		/* currently unused in tx_ops */
+		hrtimer_init(&op->thrtimer, CLOCK_MONOTONIC,
+			     HRTIMER_MODE_REL_SOFT);
+
+		/* 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 */
+
+	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 = bcm_timeval_to_ktime(msg_head->ival1);
+		op->kt_ival2 = bcm_timeval_to_ktime(msg_head->ival2);
+
+		/* disable an active timer due to zero values? */
+		if (!op->kt_ival1 && !op->kt_ival2)
+			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 * op->cfsiz + MHSIZ;
+
+free_op:
+	if (op->frames != &op->sframe)
+		kfree(op->frames);
+	kfree(op);
+	return err;
+}
+
+/*
+ * 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 timeval limitations */
+	if ((msg_head->flags & SETTIMER) && bcm_is_invalid_tv(msg_head))
+		return -EINVAL;
+
+	/* check the given can_id */
+	op = bcm_find_op(&bo->rx_ops, msg_head, 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_from_msg(op->frames, msg,
+					      msg_head->nframes * op->cfsiz);
+			if (err < 0)
+				return err;
+
+			/* clear last_frames to indicate 'nothing received' */
+			memset(op->last_frames, 0, msg_head->nframes * op->cfsiz);
+		}
+
+		op->nframes = msg_head->nframes;
+		op->flags = msg_head->flags;
+
+		/* 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;
+		op->cfsiz = CFSIZ(msg_head->flags);
+		op->flags = msg_head->flags;
+
+		if (msg_head->nframes > 1) {
+			/* create array for CAN frames and copy the data */
+			op->frames = kmalloc_array(msg_head->nframes,
+						   op->cfsiz,
+						   GFP_KERNEL);
+			if (!op->frames) {
+				kfree(op);
+				return -ENOMEM;
+			}
+
+			/* create and init array for received CAN frames */
+			op->last_frames = kcalloc(msg_head->nframes,
+						  op->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_from_msg(op->frames, msg,
+					      msg_head->nframes * op->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_SOFT);
+		op->timer.function = bcm_rx_timeout_handler;
+
+		hrtimer_init(&op->thrtimer, CLOCK_MONOTONIC,
+			     HRTIMER_MODE_REL_SOFT);
+		op->thrtimer.function = bcm_rx_thr_handler;
+
+		/* 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 */
+
+	if (op->flags & RX_RTR_FRAME) {
+		struct canfd_frame *frame0 = op->frames;
+
+		/* 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) ||
+		    (frame0->can_id == op->can_id))
+			frame0->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 = bcm_timeval_to_ktime(msg_head->ival1);
+			op->kt_ival2 = bcm_timeval_to_ktime(msg_head->ival2);
+
+			/* disable an active timer due to zero value? */
+			if (!op->kt_ival1)
+				hrtimer_cancel(&op->timer);
+
+			/*
+			 * In any case cancel the throttle timer, flush
+			 * potentially blocked msgs and reset throttle handling
+			 */
+			op->kt_lastmsg = 0;
+			hrtimer_cancel(&op->thrtimer);
+			bcm_rx_thr_flush(op);
+		}
+
+		if ((op->flags & STARTTIMER) && op->kt_ival1)
+			hrtimer_start(&op->timer, op->kt_ival1,
+				      HRTIMER_MODE_REL_SOFT);
+	}
+
+	/* 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(sock_net(sk), ifindex);
+			if (dev) {
+				err = can_rx_register(sock_net(sk), dev,
+						      op->can_id,
+						      REGMASK(op->can_id),
+						      bcm_rx_handler, op,
+						      "bcm", sk);
+
+				op->rx_reg_dev = dev;
+				dev_put(dev);
+			}
+
+		} else
+			err = can_rx_register(sock_net(sk), NULL, op->can_id,
+					      REGMASK(op->can_id),
+					      bcm_rx_handler, op, "bcm", sk);
+		if (err) {
+			/* this bcm rx op is broken -> remove it */
+			list_del(&op->list);
+			bcm_remove_op(op);
+			return err;
+		}
+	}
+
+	return msg_head->nframes * op->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,
+		       int cfsiz)
+{
+	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_from_msg(skb_put(skb, cfsiz), msg, cfsiz);
+	if (err < 0) {
+		kfree_skb(skb);
+		return err;
+	}
+
+	dev = dev_get_by_index(sock_net(sk), ifindex);
+	if (!dev) {
+		kfree_skb(skb);
+		return -ENODEV;
+	}
+
+	can_skb_prv(skb)->ifindex = dev->ifindex;
+	can_skb_prv(skb)->skbcnt = 0;
+	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 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 cfsiz;
+	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)
+		return -EINVAL;
+
+	/* read message head information */
+	ret = memcpy_from_msg((u8 *)&msg_head, msg, MHSIZ);
+	if (ret < 0)
+		return ret;
+
+	cfsiz = CFSIZ(msg_head.flags);
+	if ((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 */
+		DECLARE_SOCKADDR(struct sockaddr_can *, addr, msg->msg_name);
+
+		if (msg->msg_namelen < BCM_MIN_NAMELEN)
+			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(sock_net(sk), ifindex);
+			if (!dev)
+				return -ENODEV;
+
+			if (dev->type != ARPHRD_CAN) {
+				dev_put(dev);
+				return -ENODEV;
+			}
+
+			dev_put(dev);
+		}
+	}
+
+	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, ifindex))
+			ret = MHSIZ;
+		else
+			ret = -EINVAL;
+		break;
+
+	case RX_DELETE:
+		if (bcm_delete_rx_op(&bo->rx_ops, &msg_head, 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, cfsiz);
+		break;
+
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	release_sock(sk);
+
+	return ret;
+}
+
+/*
+ * notification handler for netdevice status changes
+ */
+static void bcm_notify(struct bcm_sock *bo, unsigned long msg,
+		       struct net_device *dev)
+{
+	struct sock *sk = &bo->sk;
+	struct bcm_op *op;
+	int notify_enodev = 0;
+
+	if (!net_eq(dev_net(dev), sock_net(sk)))
+		return;
+
+	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);
+		}
+	}
+}
+
+static int bcm_notifier(struct notifier_block *nb, unsigned long msg,
+			void *ptr)
+{
+	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+
+	if (dev->type != ARPHRD_CAN)
+		return NOTIFY_DONE;
+	if (msg != NETDEV_UNREGISTER && msg != NETDEV_DOWN)
+		return NOTIFY_DONE;
+	if (unlikely(bcm_busy_notifier)) /* Check for reentrant bug. */
+		return NOTIFY_DONE;
+
+	spin_lock(&bcm_notifier_lock);
+	list_for_each_entry(bcm_busy_notifier, &bcm_notifier_list, notifier) {
+		spin_unlock(&bcm_notifier_lock);
+		bcm_notify(bcm_busy_notifier, msg, dev);
+		spin_lock(&bcm_notifier_lock);
+	}
+	bcm_busy_notifier = NULL;
+	spin_unlock(&bcm_notifier_lock);
+	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 */
+	spin_lock(&bcm_notifier_lock);
+	list_add_tail(&bo->notifier, &bcm_notifier_list);
+	spin_unlock(&bcm_notifier_lock);
+
+	return 0;
+}
+
+/*
+ * standard socket functions
+ */
+static int bcm_release(struct socket *sock)
+{
+	struct sock *sk = sock->sk;
+	struct net *net;
+	struct bcm_sock *bo;
+	struct bcm_op *op, *next;
+
+	if (!sk)
+		return 0;
+
+	net = sock_net(sk);
+	bo = bcm_sk(sk);
+
+	/* remove bcm_ops, timer, rx_unregister(), etc. */
+
+	spin_lock(&bcm_notifier_lock);
+	while (bcm_busy_notifier == bo) {
+		spin_unlock(&bcm_notifier_lock);
+		schedule_timeout_uninterruptible(1);
+		spin_lock(&bcm_notifier_lock);
+	}
+	list_del(&bo->notifier);
+	spin_unlock(&bcm_notifier_lock);
+
+	lock_sock(sk);
+
+#if IS_ENABLED(CONFIG_PROC_FS)
+	/* remove procfs entry */
+	if (net->can.bcmproc_dir && bo->bcm_proc_read)
+		remove_proc_entry(bo->procname, net->can.bcmproc_dir);
+#endif /* CONFIG_PROC_FS */
+
+	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(net, op->ifindex);
+				if (dev) {
+					bcm_rx_unreg(dev, op);
+					dev_put(dev);
+				}
+			}
+		} else
+			can_rx_unregister(net, NULL, op->can_id,
+					  REGMASK(op->can_id),
+					  bcm_rx_handler, op);
+
+	}
+
+	synchronize_rcu();
+
+	list_for_each_entry_safe(op, next, &bo->rx_ops, list)
+		bcm_remove_op(op);
+
+	/* 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);
+	struct net *net = sock_net(sk);
+	int ret = 0;
+
+	if (len < BCM_MIN_NAMELEN)
+		return -EINVAL;
+
+	lock_sock(sk);
+
+	if (bo->bound) {
+		ret = -EISCONN;
+		goto fail;
+	}
+
+	/* bind a device to this socket */
+	if (addr->can_ifindex) {
+		struct net_device *dev;
+
+		dev = dev_get_by_index(net, addr->can_ifindex);
+		if (!dev) {
+			ret = -ENODEV;
+			goto fail;
+		}
+		if (dev->type != ARPHRD_CAN) {
+			dev_put(dev);
+			ret = -ENODEV;
+			goto fail;
+		}
+
+		bo->ifindex = dev->ifindex;
+		dev_put(dev);
+
+	} else {
+		/* no interface reference for ifindex = 0 ('any' CAN device) */
+		bo->ifindex = 0;
+	}
+
+#if IS_ENABLED(CONFIG_PROC_FS)
+	if (net->can.bcmproc_dir) {
+		/* unique socket address as filename */
+		sprintf(bo->procname, "%lu", sock_i_ino(sk));
+		bo->bcm_proc_read = proc_create_net_single(bo->procname, 0644,
+						     net->can.bcmproc_dir,
+						     bcm_proc_show, sk);
+		if (!bo->bcm_proc_read) {
+			ret = -ENOMEM;
+			goto fail;
+		}
+	}
+#endif /* CONFIG_PROC_FS */
+
+	bo->bound = 1;
+
+fail:
+	release_sock(sk);
+
+	return ret;
+}
+
+static int bcm_recvmsg(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_to_msg(msg, 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) {
+		__sockaddr_check_size(BCM_MIN_NAMELEN);
+		msg->msg_namelen = BCM_MIN_NAMELEN;
+		memcpy(msg->msg_name, skb->cb, msg->msg_namelen);
+	}
+
+	skb_free_datagram(sk, skb);
+
+	return size;
+}
+
+static int bcm_sock_no_ioctlcmd(struct socket *sock, unsigned int cmd,
+				unsigned long arg)
+{
+	/* no ioctls for socket layer -> hand it down to NIC layer */
+	return -ENOIOCTLCMD;
+}
+
+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         = bcm_sock_no_ioctlcmd,
+	.gettstamp     = sock_gettstamp,
+	.listen        = sock_no_listen,
+	.shutdown      = sock_no_shutdown,
+	.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 canbcm_pernet_init(struct net *net)
+{
+#if IS_ENABLED(CONFIG_PROC_FS)
+	/* create /proc/net/can-bcm directory */
+	net->can.bcmproc_dir = proc_net_mkdir(net, "can-bcm", net->proc_net);
+#endif /* CONFIG_PROC_FS */
+
+	return 0;
+}
+
+static void canbcm_pernet_exit(struct net *net)
+{
+#if IS_ENABLED(CONFIG_PROC_FS)
+	/* remove /proc/net/can-bcm directory */
+	if (net->can.bcmproc_dir)
+		remove_proc_entry("can-bcm", net->proc_net);
+#endif /* CONFIG_PROC_FS */
+}
+
+static struct pernet_operations canbcm_pernet_ops __read_mostly = {
+	.init = canbcm_pernet_init,
+	.exit = canbcm_pernet_exit,
+};
+
+static struct notifier_block canbcm_notifier = {
+	.notifier_call = bcm_notifier
+};
+
+static int __init bcm_module_init(void)
+{
+	int err;
+
+	pr_info("can: broadcast manager protocol\n");
+
+	err = can_proto_register(&bcm_can_proto);
+	if (err < 0) {
+		printk(KERN_ERR "can: registration of bcm protocol failed\n");
+		return err;
+	}
+
+	register_pernet_subsys(&canbcm_pernet_ops);
+	register_netdevice_notifier(&canbcm_notifier);
+	return 0;
+}
+
+static void __exit bcm_module_exit(void)
+{
+	can_proto_unregister(&bcm_can_proto);
+	unregister_netdevice_notifier(&canbcm_notifier);
+	unregister_pernet_subsys(&canbcm_pernet_ops);
+}
+
+module_init(bcm_module_init);
+module_exit(bcm_module_exit);