[CAN]: Add broadcast manager (bcm) protocol

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

Signed-off-by: Oliver Hartkopp <oliver.hartkopp@volkswagen.de>
Signed-off-by: Urs Thuermann <urs.thuermann@volkswagen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1561 insertions, 0 deletions

diff --git a/net/can/bcm.c b/net/can/bcm.c
new file mode 100644
index 000000000000..bd4282dae754
--- /dev/null
+++ b/net/can/bcm.c
@@ -0,0 +1,1561 @@
+/*
+ * 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 <socketcan-users@lists.berlios.de>
+ *
+ */
+
+#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 <oliver.hartkopp@volkswagen.de>");
+
+/* 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);