dev.c

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/*
 * Copyright (C) 2005 Marc Kleine-Budde, Pengutronix
 * Copyright (C) 2006 Andrey Volkov, Varma Electronics
 * Copyright (C) 2008-2009 Wolfgang Grandegger <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the version 2 of the GNU General Public License
 * as published by the Free Software Foundation
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/can.h>
#include <linux/can/dev.h>
#include <linux/can/netlink.h>
#include <net/rtnetlink.h>

#define MOD_DESC "CAN device driver interface"

MODULE_DESCRIPTION(MOD_DESC);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Wolfgang Grandegger <[email protected]>");

/* CAN DLC to real data length conversion helpers */

static const u8 dlc2len[] = {0, 1, 2, 3, 4, 5, 6, 7,
                 8, 12, 16, 20, 24, 32, 48, 64};

/* get data length from can_dlc with sanitized can_dlc */
u8 can_dlc2len(u8 can_dlc)
{
    return dlc2len[can_dlc & 0x0F];
}
EXPORT_SYMBOL_GPL(can_dlc2len);

static const u8 len2dlc[] = {0, 1, 2, 3, 4, 5, 6, 7, 8,     /* 0 - 8 */
                 9, 9, 9, 9,            /* 9 - 12 */
                 10, 10, 10, 10,            /* 13 - 16 */
                 11, 11, 11, 11,            /* 17 - 20 */
                 12, 12, 12, 12,            /* 21 - 24 */
                 13, 13, 13, 13, 13, 13, 13, 13,    /* 25 - 32 */
                 14, 14, 14, 14, 14, 14, 14, 14,    /* 33 - 40 */
                 14, 14, 14, 14, 14, 14, 14, 14,    /* 41 - 48 */
                 15, 15, 15, 15, 15, 15, 15, 15,    /* 49 - 56 */
                 15, 15, 15, 15, 15, 15, 15, 15};   /* 57 - 64 */

/* map the sanitized data length to an appropriate data length code */
u8 can_len2dlc(u8 len)
{
    if (unlikely(len > 64))
        return 0xF;

    return len2dlc[len];
}
EXPORT_SYMBOL_GPL(can_len2dlc);

#ifdef CONFIG_CAN_CALC_BITTIMING
#define CAN_CALC_MAX_ERROR 50 /* in one-tenth of a percent */

/*
 * Bit-timing calculation derived from:
 *
 * Code based on LinCAN sources and H8S2638 project
 * Copyright 2004-2006 Pavel Pisa - DCE FELK CVUT cz
 * Copyright 2005      Stanislav Marek
 * email: [email protected]
 *
 * Calculates proper bit-timing parameters for a specified bit-rate
 * and sample-point, which can then be used to set the bit-timing
 * registers of the CAN controller. You can find more information
 * in the header file linux/can/netlink.h.
 */
static int can_update_spt(const struct can_bittiming_const *btc,
              int sampl_pt, int tseg, int *tseg1, int *tseg2)
{
    *tseg2 = tseg + 1 - (sampl_pt * (tseg + 1)) / 1000;
    if (*tseg2 < btc->tseg2_min)
        *tseg2 = btc->tseg2_min;
    if (*tseg2 > btc->tseg2_max)
        *tseg2 = btc->tseg2_max;
    *tseg1 = tseg - *tseg2;
    if (*tseg1 > btc->tseg1_max) {
        *tseg1 = btc->tseg1_max;
        *tseg2 = tseg - *tseg1;
    }
    return 1000 * (tseg + 1 - *tseg2) / (tseg + 1);
}

static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt)
{
    struct can_priv *priv = netdev_priv(dev);
    const struct can_bittiming_const *btc = priv->bittiming_const;
    long rate, best_rate = 0;
    long best_error = 1000000000, error = 0;
    int best_tseg = 0, best_brp = 0, brp = 0;
    int tsegall, tseg = 0, tseg1 = 0, tseg2 = 0;
    int spt_error = 1000, spt = 0, sampl_pt;
    u64 v64;

    if (!priv->bittiming_const)
        return -ENOTSUPP;

    /* Use CIA recommended sample points */
    if (bt->sample_point) {
        sampl_pt = bt->sample_point;
    } else {
        if (bt->bitrate > 800000)
            sampl_pt = 750;
        else if (bt->bitrate > 500000)
            sampl_pt = 800;
        else
            sampl_pt = 875;
    }

    /* tseg even = round down, odd = round up */
    for (tseg = (btc->tseg1_max + btc->tseg2_max) * 2 + 1;
         tseg >= (btc->tseg1_min + btc->tseg2_min) * 2; tseg--) {
        tsegall = 1 + tseg / 2;
        /* Compute all possible tseg choices (tseg=tseg1+tseg2) */
        brp = priv->clock.freq / (tsegall * bt->bitrate) + tseg % 2;
        /* chose brp step which is possible in system */
        brp = (brp / btc->brp_inc) * btc->brp_inc;
        if ((brp < btc->brp_min) || (brp > btc->brp_max))
            continue;
        rate = priv->clock.freq / (brp * tsegall);
        error = bt->bitrate - rate;
        /* tseg brp biterror */
        if (error < 0)
            error = -error;
        if (error > best_error)
            continue;
        best_error = error;
        if (error == 0) {
            spt = can_update_spt(btc, sampl_pt, tseg / 2,
                         &tseg1, &tseg2);
            error = sampl_pt - spt;
            if (error < 0)
                error = -error;
            if (error > spt_error)
                continue;
            spt_error = error;
        }
        best_tseg = tseg / 2;
        best_brp = brp;
        best_rate = rate;
        if (error == 0)
            break;
    }

    if (best_error) {
        /* Error in one-tenth of a percent */
        error = (best_error * 1000) / bt->bitrate;
        if (error > CAN_CALC_MAX_ERROR) {
            netdev_err(dev,
                   "bitrate error %ld.%ld%% too high\n",
                   error / 10, error % 10);
            return -EDOM;
        } else {
            netdev_warn(dev, "bitrate error %ld.%ld%%\n",
                    error / 10, error % 10);
        }
    }

    /* real sample point */
    bt->sample_point = can_update_spt(btc, sampl_pt, best_tseg,
                      &tseg1, &tseg2);

    v64 = (u64)best_brp * 1000000000UL;
    do_div(v64, priv->clock.freq);
    bt->tq = (u32)v64;
    bt->prop_seg = tseg1 / 2;
    bt->phase_seg1 = tseg1 - bt->prop_seg;
    bt->phase_seg2 = tseg2;

    /* check for sjw user settings */
    if (!bt->sjw || !btc->sjw_max)
        bt->sjw = 1;
    else {
        /* bt->sjw is at least 1 -> sanitize upper bound to sjw_max */
        if (bt->sjw > btc->sjw_max)
            bt->sjw = btc->sjw_max;
        /* bt->sjw must not be higher than tseg2 */
        if (tseg2 < bt->sjw)
            bt->sjw = tseg2;
    }

    bt->brp = best_brp;
    /* real bit-rate */
    bt->bitrate = priv->clock.freq / (bt->brp * (tseg1 + tseg2 + 1));

    return 0;
}
#else /* !CONFIG_CAN_CALC_BITTIMING */
static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt)
{
    netdev_err(dev, "bit-timing calculation not available\n");
    return -EINVAL;
}
#endif /* CONFIG_CAN_CALC_BITTIMING */

/*
 * Checks the validity of the specified bit-timing parameters prop_seg,
 * phase_seg1, phase_seg2 and sjw and tries to determine the bitrate
 * prescaler value brp. You can find more information in the header
 * file linux/can/netlink.h.
 */
static int can_fixup_bittiming(struct net_device *dev, struct can_bittiming *bt)
{
    struct can_priv *priv = netdev_priv(dev);
    const struct can_bittiming_const *btc = priv->bittiming_const;
    int tseg1, alltseg;
    u64 brp64;

    if (!priv->bittiming_const)
        return -ENOTSUPP;

    tseg1 = bt->prop_seg + bt->phase_seg1;
    if (!bt->sjw)
        bt->sjw = 1;
    if (bt->sjw > btc->sjw_max ||
        tseg1 < btc->tseg1_min || tseg1 > btc->tseg1_max ||
        bt->phase_seg2 < btc->tseg2_min || bt->phase_seg2 > btc->tseg2_max)
        return -ERANGE;

    brp64 = (u64)priv->clock.freq * (u64)bt->tq;
    if (btc->brp_inc > 1)
        do_div(brp64, btc->brp_inc);
    brp64 += 500000000UL - 1;
    do_div(brp64, 1000000000UL); /* the practicable BRP */
    if (btc->brp_inc > 1)
        brp64 *= btc->brp_inc;
    bt->brp = (u32)brp64;

    if (bt->brp < btc->brp_min || bt->brp > btc->brp_max)
        return -EINVAL;

    alltseg = bt->prop_seg + bt->phase_seg1 + bt->phase_seg2 + 1;
    bt->bitrate = priv->clock.freq / (bt->brp * alltseg);
    bt->sample_point = ((tseg1 + 1) * 1000) / alltseg;

    return 0;
}

static int can_get_bittiming(struct net_device *dev, struct can_bittiming *bt)
{
    struct can_priv *priv = netdev_priv(dev);
    int err;

    /* Check if the CAN device has bit-timing parameters */
    if (priv->bittiming_const) {

        /* Non-expert mode? Check if the bitrate has been pre-defined */
        if (!bt->tq)
            /* Determine bit-timing parameters */
            err = can_calc_bittiming(dev, bt);
        else
            /* Check bit-timing params and calculate proper brp */
            err = can_fixup_bittiming(dev, bt);
        if (err)
            return err;
    }

    return 0;
}

/*
 * Local echo of CAN messages
 *
 * CAN network devices *should* support a local echo functionality
 * (see Documentation/networking/can.txt). To test the handling of CAN
 * interfaces that do not support the local echo both driver types are
 * implemented. In the case that the driver does not support the echo
 * the IFF_ECHO remains clear in dev->flags. This causes the PF_CAN core
 * to perform the echo as a fallback solution.
 */
static void can_flush_echo_skb(struct net_device *dev)
{
    struct can_priv *priv = netdev_priv(dev);
    struct net_device_stats *stats = &dev->stats;
    int i;

    for (i = 0; i < priv->echo_skb_max; i++) {
        if (priv->echo_skb[i]) {
            kfree_skb(priv->echo_skb[i]);
            priv->echo_skb[i] = NULL;
            stats->tx_dropped++;
            stats->tx_aborted_errors++;
        }
    }
}

/*
 * Put the skb on the stack to be looped backed locally lateron
 *
 * The function is typically called in the start_xmit function
 * of the device driver. The driver must protect access to
 * priv->echo_skb, if necessary.
 */
void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
              unsigned int idx)
{
    struct can_priv *priv = netdev_priv(dev);

    BUG_ON(idx >= priv->echo_skb_max);

    /* check flag whether this packet has to be looped back */
    if (!(dev->flags & IFF_ECHO) || skb->pkt_type != PACKET_LOOPBACK) {
        kfree_skb(skb);
        return;
    }

    if (!priv->echo_skb[idx]) {
        struct sock *srcsk = skb->sk;

        if (atomic_read(&skb->users) != 1) {
            struct sk_buff *old_skb = skb;

            skb = skb_clone(old_skb, GFP_ATOMIC);
            kfree_skb(old_skb);
            if (!skb)
                return;
        } else
            skb_orphan(skb);

        skb->sk = srcsk;

        /* make settings for echo to reduce code in irq context */
        skb->protocol = htons(ETH_P_CAN);
        skb->pkt_type = PACKET_BROADCAST;
        skb->ip_summed = CHECKSUM_UNNECESSARY;
        skb->dev = dev;

        /* save this skb for tx interrupt echo handling */
        priv->echo_skb[idx] = skb;
    } else {
        /* locking problem with netif_stop_queue() ?? */
        netdev_err(dev, "%s: BUG! echo_skb is occupied!\n", __func__);
        kfree_skb(skb);
    }
}
EXPORT_SYMBOL_GPL(can_put_echo_skb);

/*
 * Get the skb from the stack and loop it back locally
 *
 * The function is typically called when the TX done interrupt
 * is handled in the device driver. The driver must protect
 * access to priv->echo_skb, if necessary.
 */
unsigned int can_get_echo_skb(struct net_device *dev, unsigned int idx)
{
    struct can_priv *priv = netdev_priv(dev);

    BUG_ON(idx >= priv->echo_skb_max);

    if (priv->echo_skb[idx]) {
        struct sk_buff *skb = priv->echo_skb[idx];
        struct can_frame *cf = (struct can_frame *)skb->data;
        u8 dlc = cf->can_dlc;

        netif_rx(priv->echo_skb[idx]);
        priv->echo_skb[idx] = NULL;

        return dlc;
    }

    return 0;
}
EXPORT_SYMBOL_GPL(can_get_echo_skb);

/*
  * Remove the skb from the stack and free it.
  *
  * The function is typically called when TX failed.
  */
void can_free_echo_skb(struct net_device *dev, unsigned int idx)
{
    struct can_priv *priv = netdev_priv(dev);

    BUG_ON(idx >= priv->echo_skb_max);

    if (priv->echo_skb[idx]) {
        kfree_skb(priv->echo_skb[idx]);
        priv->echo_skb[idx] = NULL;
    }
}
EXPORT_SYMBOL_GPL(can_free_echo_skb);

/*
 * CAN device restart for bus-off recovery
 */
static void can_restart(unsigned long data)
{
    struct net_device *dev = (struct net_device *)data;
    struct can_priv *priv = netdev_priv(dev);
    struct net_device_stats *stats = &dev->stats;
    struct sk_buff *skb;
    struct can_frame *cf;
    int err;

    BUG_ON(netif_carrier_ok(dev));

    /*
     * No synchronization needed because the device is bus-off and
     * no messages can come in or go out.
     */
    can_flush_echo_skb(dev);

    /* send restart message upstream */
    skb = alloc_can_err_skb(dev, &cf);
    if (skb == NULL) {
        err = -ENOMEM;
        goto restart;
    }
    cf->can_id |= CAN_ERR_RESTARTED;

    netif_rx(skb);

    stats->rx_packets++;
    stats->rx_bytes += cf->can_dlc;

restart:
    netdev_dbg(dev, "restarted\n");
    priv->can_stats.restarts++;

    /* Now restart the device */
    err = priv->do_set_mode(dev, CAN_MODE_START);

    netif_carrier_on(dev);
    if (err)
        netdev_err(dev, "Error %d during restart", err);
}

int can_restart_now(struct net_device *dev)
{
    struct can_priv *priv = netdev_priv(dev);

    /*
     * A manual restart is only permitted if automatic restart is
     * disabled and the device is in the bus-off state
     */
    if (priv->restart_ms)
        return -EINVAL;
    if (priv->state != CAN_STATE_BUS_OFF)
        return -EBUSY;

    /* Runs as soon as possible in the timer context */
    mod_timer(&priv->restart_timer, jiffies);

    return 0;
}

/*
 * CAN bus-off
 *
 * This functions should be called when the device goes bus-off to
 * tell the netif layer that no more packets can be sent or received.
 * If enabled, a timer is started to trigger bus-off recovery.
 */
void can_bus_off(struct net_device *dev)
{
    struct can_priv *priv = netdev_priv(dev);

    netdev_dbg(dev, "bus-off\n");

    netif_carrier_off(dev);
    priv->can_stats.bus_off++;

    if (priv->restart_ms)
        mod_timer(&priv->restart_timer,
              jiffies + (priv->restart_ms * HZ) / 1000);
}
EXPORT_SYMBOL_GPL(can_bus_off);

static void can_setup(struct net_device *dev)
{
    dev->type = ARPHRD_CAN;
    dev->mtu = CAN_MTU;
    dev->hard_header_len = 0;
    dev->addr_len = 0;
    dev->tx_queue_len = 10;

    /* New-style flags. */
    dev->flags = IFF_NOARP;
    dev->features = NETIF_F_HW_CSUM;
}

struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf)
{
    struct sk_buff *skb;

    skb = netdev_alloc_skb(dev, sizeof(struct can_frame));
    if (unlikely(!skb))
        return NULL;

    skb->protocol = htons(ETH_P_CAN);
    skb->pkt_type = PACKET_BROADCAST;
    skb->ip_summed = CHECKSUM_UNNECESSARY;
    *cf = (struct can_frame *)skb_put(skb, sizeof(struct can_frame));
    memset(*cf, 0, sizeof(struct can_frame));

    return skb;
}
EXPORT_SYMBOL_GPL(alloc_can_skb);

struct sk_buff *alloc_can_err_skb(struct net_device *dev, struct can_frame **cf)
{
    struct sk_buff *skb;

    skb = alloc_can_skb(dev, cf);
    if (unlikely(!skb))
        return NULL;

    (*cf)->can_id = CAN_ERR_FLAG;
    (*cf)->can_dlc = CAN_ERR_DLC;

    return skb;
}
EXPORT_SYMBOL_GPL(alloc_can_err_skb);

/*
 * Allocate and setup space for the CAN network device
 */
struct net_device *alloc_candev(int sizeof_priv, unsigned int echo_skb_max)
{
    struct net_device *dev;
    struct can_priv *priv;
    int size;

    if (echo_skb_max)
        size = ALIGN(sizeof_priv, sizeof(struct sk_buff *)) +
            echo_skb_max * sizeof(struct sk_buff *);
    else
        size = sizeof_priv;

    dev = alloc_netdev(size, "can%d", can_setup);
    if (!dev)
        return NULL;

    priv = netdev_priv(dev);

    if (echo_skb_max) {
        priv->echo_skb_max = echo_skb_max;
        priv->echo_skb = (void *)priv +
            ALIGN(sizeof_priv, sizeof(struct sk_buff *));
    }

    priv->state = CAN_STATE_STOPPED;

    init_timer(&priv->restart_timer);

    return dev;
}
EXPORT_SYMBOL_GPL(alloc_candev);

/*
 * Free space of the CAN network device
 */
void free_candev(struct net_device *dev)
{
    free_netdev(dev);
}
EXPORT_SYMBOL_GPL(free_candev);

/*
 * Common open function when the device gets opened.
 *
 * This function should be called in the open function of the device
 * driver.
 */
int open_candev(struct net_device *dev)
{
    struct can_priv *priv = netdev_priv(dev);

    if (!priv->bittiming.tq && !priv->bittiming.bitrate) {
        netdev_err(dev, "bit-timing not yet defined\n");
        return -EINVAL;
    }

    /* Switch carrier on if device was stopped while in bus-off state */
    if (!netif_carrier_ok(dev))
        netif_carrier_on(dev);

    setup_timer(&priv->restart_timer, can_restart, (unsigned long)dev);

    return 0;
}
EXPORT_SYMBOL_GPL(open_candev);

/*
 * Common close function for cleanup before the device gets closed.
 *
 * This function should be called in the close function of the device
 * driver.
 */
void close_candev(struct net_device *dev)
{
    struct can_priv *priv = netdev_priv(dev);

    if (del_timer_sync(&priv->restart_timer))
        dev_put(dev);
    can_flush_echo_skb(dev);
}
EXPORT_SYMBOL_GPL(close_candev);

/*
 * CAN netlink interface
 */
static const struct nla_policy can_policy[IFLA_CAN_MAX + 1] = {
    [IFLA_CAN_STATE]    = { .type = NLA_U32 },
    [IFLA_CAN_CTRLMODE] = { .len = sizeof(struct can_ctrlmode) },
    [IFLA_CAN_RESTART_MS]   = { .type = NLA_U32 },
    [IFLA_CAN_RESTART]  = { .type = NLA_U32 },
    [IFLA_CAN_BITTIMING]    = { .len = sizeof(struct can_bittiming) },
    [IFLA_CAN_BITTIMING_CONST]
                = { .len = sizeof(struct can_bittiming_const) },
    [IFLA_CAN_CLOCK]    = { .len = sizeof(struct can_clock) },
    [IFLA_CAN_BERR_COUNTER] = { .len = sizeof(struct can_berr_counter) },
};

static int can_changelink(struct net_device *dev,
              struct nlattr *tb[], struct nlattr *data[])
{
    struct can_priv *priv = netdev_priv(dev);
    int err;

    /* We need synchronization with dev->stop() */
    ASSERT_RTNL();

    if (data[IFLA_CAN_CTRLMODE]) {
        struct can_ctrlmode *cm;

        /* Do not allow changing controller mode while running */
        if (dev->flags & IFF_UP)
            return -EBUSY;
        cm = nla_data(data[IFLA_CAN_CTRLMODE]);
        if (cm->flags & ~priv->ctrlmode_supported)
            return -EOPNOTSUPP;
        priv->ctrlmode &= ~cm->mask;
        priv->ctrlmode |= cm->flags;
    }

    if (data[IFLA_CAN_BITTIMING]) {
        struct can_bittiming bt;

        /* Do not allow changing bittiming while running */
        if (dev->flags & IFF_UP)
            return -EBUSY;
        memcpy(&bt, nla_data(data[IFLA_CAN_BITTIMING]), sizeof(bt));
        if ((!bt.bitrate && !bt.tq) || (bt.bitrate && bt.tq))
            return -EINVAL;
        err = can_get_bittiming(dev, &bt);
        if (err)
            return err;
        memcpy(&priv->bittiming, &bt, sizeof(bt));

        if (priv->do_set_bittiming) {
            /* Finally, set the bit-timing registers */
            err = priv->do_set_bittiming(dev);
            if (err)
                return err;
        }
    }

    if (data[IFLA_CAN_RESTART_MS]) {
        /* Do not allow changing restart delay while running */
        if (dev->flags & IFF_UP)
            return -EBUSY;
        priv->restart_ms = nla_get_u32(data[IFLA_CAN_RESTART_MS]);
    }

    if (data[IFLA_CAN_RESTART]) {
        /* Do not allow a restart while not running */
        if (!(dev->flags & IFF_UP))
            return -EINVAL;
        err = can_restart_now(dev);
        if (err)
            return err;
    }

    return 0;
}

static size_t can_get_size(const struct net_device *dev)
{
    struct can_priv *priv = netdev_priv(dev);
    size_t size;

    size = nla_total_size(sizeof(u32));   /* IFLA_CAN_STATE */
    size += sizeof(struct can_ctrlmode);  /* IFLA_CAN_CTRLMODE */
    size += nla_total_size(sizeof(u32));  /* IFLA_CAN_RESTART_MS */
    size += sizeof(struct can_bittiming); /* IFLA_CAN_BITTIMING */
    size += sizeof(struct can_clock);     /* IFLA_CAN_CLOCK */
    if (priv->do_get_berr_counter)        /* IFLA_CAN_BERR_COUNTER */
        size += sizeof(struct can_berr_counter);
    if (priv->bittiming_const)        /* IFLA_CAN_BITTIMING_CONST */
        size += sizeof(struct can_bittiming_const);

    return size;
}

static int can_fill_info(struct sk_buff *skb, const struct net_device *dev)
{
    struct can_priv *priv = netdev_priv(dev);
    struct can_ctrlmode cm = {.flags = priv->ctrlmode};
    struct can_berr_counter bec;
    enum can_state state = priv->state;

    if (priv->do_get_state)
        priv->do_get_state(dev, &state);
    if (nla_put_u32(skb, IFLA_CAN_STATE, state) ||
        nla_put(skb, IFLA_CAN_CTRLMODE, sizeof(cm), &cm) ||
        nla_put_u32(skb, IFLA_CAN_RESTART_MS, priv->restart_ms) ||
        nla_put(skb, IFLA_CAN_BITTIMING,
            sizeof(priv->bittiming), &priv->bittiming) ||
        nla_put(skb, IFLA_CAN_CLOCK, sizeof(cm), &priv->clock) ||
        (priv->do_get_berr_counter &&
         !priv->do_get_berr_counter(dev, &bec) &&
         nla_put(skb, IFLA_CAN_BERR_COUNTER, sizeof(bec), &bec)) ||
        (priv->bittiming_const &&
         nla_put(skb, IFLA_CAN_BITTIMING_CONST,
             sizeof(*priv->bittiming_const), priv->bittiming_const)))
        goto nla_put_failure;
    return 0;

nla_put_failure:
    return -EMSGSIZE;
}

static size_t can_get_xstats_size(const struct net_device *dev)
{
    return sizeof(struct can_device_stats);
}

static int can_fill_xstats(struct sk_buff *skb, const struct net_device *dev)
{
    struct can_priv *priv = netdev_priv(dev);

    if (nla_put(skb, IFLA_INFO_XSTATS,
            sizeof(priv->can_stats), &priv->can_stats))
        goto nla_put_failure;
    return 0;

nla_put_failure:
    return -EMSGSIZE;
}

static int can_newlink(struct net *src_net, struct net_device *dev,
               struct nlattr *tb[], struct nlattr *data[])
{
    return -EOPNOTSUPP;
}

static struct rtnl_link_ops can_link_ops __read_mostly = {
    .kind       = "can",
    .maxtype    = IFLA_CAN_MAX,
    .policy     = can_policy,
    .setup      = can_setup,
    .newlink    = can_newlink,
    .changelink = can_changelink,
    .get_size   = can_get_size,
    .fill_info  = can_fill_info,
    .get_xstats_size = can_get_xstats_size,
    .fill_xstats    = can_fill_xstats,
};

/*
 * Register the CAN network device
 */
int register_candev(struct net_device *dev)
{
    dev->rtnl_link_ops = &can_link_ops;
    return register_netdev(dev);
}
EXPORT_SYMBOL_GPL(register_candev);

/*
 * Unregister the CAN network device
 */
void unregister_candev(struct net_device *dev)
{
    unregister_netdev(dev);
}
EXPORT_SYMBOL_GPL(unregister_candev);

static __init int can_dev_init(void)
{
    int err;

    err = rtnl_link_register(&can_link_ops);
    if (!err)
        printk(KERN_INFO MOD_DESC "\n");

    return err;
}
module_init(can_dev_init);

static __exit void can_dev_exit(void)
{
    rtnl_link_unregister(&can_link_ops);
}
module_exit(can_dev_exit);

MODULE_ALIAS_RTNL_LINK("can");