/*
 * Copyright 2011, Siemens AG
 * written by Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
 */

/*
 * Based on patches from Jon Smirl <jonsmirl@gmail.com>
 * Copyright (c) 2011 Jon Smirl <jonsmirl@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2
 * 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.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

/* Jon's code is based on 6lowpan implementation for Contiki which is:
 * Copyright (c) 2008, Swedish Institute of Computer Science.
 * 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 the Institute nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE 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 INSTITUTE 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/bitops.h>
#include <linux/if_arp.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/netdevice.h>
#include <net/af_ieee802154.h>
#include <net/ieee802154.h>
#include <net/ieee802154_netdev.h>
#include <net/ipv6.h>

#include "6lowpan.h"

static LIST_HEAD(lowpan_devices);

/* private device info */
struct lowpan_dev_info {
        struct net_device       *real_dev; /* real WPAN device ptr */
        struct mutex            dev_list_mtx; /* mutex for list ops */
        unsigned short          fragment_tag;
};

struct lowpan_dev_record {
        struct net_device *ldev;
        struct list_head list;
};

struct lowpan_fragment {
        struct sk_buff          *skb;           /* skb to be assembled */
        u16                     length;         /* length to be assemled */
        u32                     bytes_rcv;      /* bytes received */
        u16                     tag;            /* current fragment tag */
        struct timer_list       timer;          /* assembling timer */
        struct list_head        list;           /* fragments list */
};

static LIST_HEAD(lowpan_fragments);
static DEFINE_SPINLOCK(flist_lock);

static inline struct
lowpan_dev_info *lowpan_dev_info(const struct net_device *dev)
{
        return netdev_priv(dev);
}

static inline void lowpan_address_flip(u8 *src, u8 *dest)
{
        int i;
        for (i = 0; i < IEEE802154_ADDR_LEN; i++)
                (dest)[IEEE802154_ADDR_LEN - i - 1] = (src)[i];
}

static int lowpan_header_create(struct sk_buff *skb,
                           struct net_device *dev,
                           unsigned short type, const void *_daddr,
                           const void *_saddr, unsigned int len)
{
        const u8 *saddr = _saddr;
        const u8 *daddr = _daddr;
        struct ieee802154_addr sa, da;

        /* TODO:
         * if this package isn't ipv6 one, where should it be routed?
         */
        if (type != ETH_P_IPV6)
                return 0;

        if (!saddr)
                saddr = dev->dev_addr;

        raw_dump_inline(__func__, "saddr", (unsigned char *)saddr, 8);
        raw_dump_inline(__func__, "daddr", (unsigned char *)daddr, 8);

        lowpan_header_compress(skb, dev, type, daddr, saddr, len);

        /*
         * NOTE1: I'm still unsure about the fact that compression and WPAN
         * header are created here and not later in the xmit. So wait for
         * an opinion of net maintainers.
         */
        /*
         * NOTE2: to be absolutely correct, we must derive PANid information
         * from MAC subif of the 'dev' and 'real_dev' network devices, but
         * this isn't implemented in mainline yet, so currently we assign 0xff
         */
        mac_cb(skb)->flags = IEEE802154_FC_TYPE_DATA;
        mac_cb(skb)->seq = ieee802154_mlme_ops(dev)->get_dsn(dev);

        /* prepare wpan address data */
        sa.addr_type = IEEE802154_ADDR_LONG;
        sa.pan_id = ieee802154_mlme_ops(dev)->get_pan_id(dev);

        memcpy(&(sa.hwaddr), saddr, 8);
        /* intra-PAN communications */
        da.pan_id = ieee802154_mlme_ops(dev)->get_pan_id(dev);

        /*
         * if the destination address is the broadcast address, use the
         * corresponding short address
         */
        if (lowpan_is_addr_broadcast(daddr)) {
                da.addr_type = IEEE802154_ADDR_SHORT;
                da.short_addr = IEEE802154_ADDR_BROADCAST;
        } else {
                da.addr_type = IEEE802154_ADDR_LONG;
                memcpy(&(da.hwaddr), daddr, IEEE802154_ADDR_LEN);

                /* request acknowledgment */
                mac_cb(skb)->flags |= MAC_CB_FLAG_ACKREQ;
        }

        return dev_hard_header(skb, lowpan_dev_info(dev)->real_dev,
                        type, (void *)&da, (void *)&sa, skb->len);
}

static int lowpan_give_skb_to_devices(struct sk_buff *skb,
                                        struct net_device *dev)
{
        struct lowpan_dev_record *entry;
        struct sk_buff *skb_cp;
        int stat = NET_RX_SUCCESS;

        rcu_read_lock();
        list_for_each_entry_rcu(entry, &lowpan_devices, list)
                if (lowpan_dev_info(entry->ldev)->real_dev == skb->dev) {
                        skb_cp = skb_copy(skb, GFP_ATOMIC);
                        if (!skb_cp) {
                                stat = -ENOMEM;
                                break;
                        }

                        skb_cp->dev = entry->ldev;
                        stat = netif_rx(skb_cp);
                }
        rcu_read_unlock();

        return stat;
}

static void lowpan_fragment_timer_expired(unsigned long entry_addr)
{
        struct lowpan_fragment *entry = (struct lowpan_fragment *)entry_addr;

        pr_debug("timer expired for frame with tag %d\n", entry->tag);

        list_del(&entry->list);
        dev_kfree_skb(entry->skb);
        kfree(entry);
}

static struct lowpan_fragment *
lowpan_alloc_new_frame(struct sk_buff *skb, u16 len, u16 tag)
{
        struct lowpan_fragment *frame;

        frame = kzalloc(sizeof(struct lowpan_fragment),
                        GFP_ATOMIC);
        if (!frame)
                goto frame_err;

        INIT_LIST_HEAD(&frame->list);

        frame->length = len;
        frame->tag = tag;

        /* allocate buffer for frame assembling */
        frame->skb = netdev_alloc_skb_ip_align(skb->dev, frame->length +
                                               sizeof(struct ipv6hdr));

        if (!frame->skb)
                goto skb_err;

        frame->skb->priority = skb->priority;

        /* reserve headroom for uncompressed ipv6 header */
        skb_reserve(frame->skb, sizeof(struct ipv6hdr));
        skb_put(frame->skb, frame->length);

        /* copy the first control block to keep a
         * trace of the link-layer addresses in case
         * of a link-local compressed address
         */
        memcpy(frame->skb->cb, skb->cb, sizeof(skb->cb));

        init_timer(&frame->timer);
        /* time out is the same as for ipv6 - 60 sec */
        frame->timer.expires = jiffies + LOWPAN_FRAG_TIMEOUT;
        frame->timer.data = (unsigned long)frame;
        frame->timer.function = lowpan_fragment_timer_expired;

        add_timer(&frame->timer);

        list_add_tail(&frame->list, &lowpan_fragments);

        return frame;

skb_err:
        kfree(frame);
frame_err:
        return NULL;
}

static int process_data(struct sk_buff *skb)
{
        u8 iphc0, iphc1;
        const struct ieee802154_addr *_saddr, *_daddr;

        raw_dump_table(__func__, "raw skb data dump", skb->data, skb->len);
        /* at least two bytes will be used for the encoding */
        if (skb->len < 2)
                goto drop;

        if (lowpan_fetch_skb_u8(skb, &iphc0))
                goto drop;

        /* fragments assembling */
        switch (iphc0 & LOWPAN_DISPATCH_MASK) {
        case LOWPAN_DISPATCH_FRAG1:
        case LOWPAN_DISPATCH_FRAGN:
        {
                struct lowpan_fragment *frame;
                /* slen stores the rightmost 8 bits of the 11 bits length */
                u8 slen, offset = 0;
                u16 len, tag;
                bool found = false;

                if (lowpan_fetch_skb_u8(skb, &slen) || /* frame length */
                    lowpan_fetch_skb_u16(skb, &tag))  /* fragment tag */
                        goto drop;

                /* adds the 3 MSB to the 8 LSB to retrieve the 11 bits length */
                len = ((iphc0 & 7) << 8) | slen;

                if ((iphc0 & LOWPAN_DISPATCH_MASK) == LOWPAN_DISPATCH_FRAG1) {
                        pr_debug("%s received a FRAG1 packet (tag: %d, "
                                 "size of the entire IP packet: %d)",
                                 __func__, tag, len);
                } else { /* FRAGN */
                        if (lowpan_fetch_skb_u8(skb, &offset))
                                goto unlock_and_drop;
                        pr_debug("%s received a FRAGN packet (tag: %d, "
                                 "size of the entire IP packet: %d, "
                                 "offset: %d)", __func__, tag, len, offset * 8);
                }

                /*
                 * check if frame assembling with the same tag is
                 * already in progress
                 */
                spin_lock_bh(&flist_lock);

                list_for_each_entry(frame, &lowpan_fragments, list)
                        if (frame->tag == tag) {
                                found = true;
                                break;
                        }

                /* alloc new frame structure */
                if (!found) {
                        pr_debug("%s first fragment received for tag %d, "
                                 "begin packet reassembly", __func__, tag);
                        frame = lowpan_alloc_new_frame(skb, len, tag);
                        if (!frame)
                                goto unlock_and_drop;
                }

                /* if payload fits buffer, copy it */
                if (likely((offset * 8 + skb->len) <= frame->length))
                        skb_copy_to_linear_data_offset(frame->skb, offset * 8,
                                                        skb->data, skb->len);
                else
                        goto unlock_and_drop;

                frame->bytes_rcv += skb->len;

                /* frame assembling complete */
                if ((frame->bytes_rcv == frame->length) &&
                     frame->timer.expires > jiffies) {
                        /* if timer haven't expired - first of all delete it */
                        del_timer_sync(&frame->timer);
                        list_del(&frame->list);
                        spin_unlock_bh(&flist_lock);

                        pr_debug("%s successfully reassembled fragment "
                                 "(tag %d)", __func__, tag);

                        dev_kfree_skb(skb);
                        skb = frame->skb;
                        kfree(frame);

                        if (lowpan_fetch_skb_u8(skb, &iphc0))
                                goto drop;

                        break;
                }
                spin_unlock_bh(&flist_lock);

                return kfree_skb(skb), 0;
        }
        default:
                break;
        }

        if (lowpan_fetch_skb_u8(skb, &iphc1))
                goto drop;

        _saddr = &mac_cb(skb)->sa;
        _daddr = &mac_cb(skb)->da;

        return lowpan_process_data(skb, skb->dev, (u8 *)_saddr->hwaddr,
                                _saddr->addr_type, IEEE802154_ADDR_LEN,
                                (u8 *)_daddr->hwaddr, _daddr->addr_type,
                                IEEE802154_ADDR_LEN, iphc0, iphc1,
                                lowpan_give_skb_to_devices);

unlock_and_drop:
        spin_unlock_bh(&flist_lock);
drop:
        kfree_skb(skb);
        return -EINVAL;
}

static int lowpan_set_address(struct net_device *dev, void *p)
{
        struct sockaddr *sa = p;

        if (netif_running(dev))
                return -EBUSY;

        /* TODO: validate addr */
        memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);

        return 0;
}

static int
lowpan_fragment_xmit(struct sk_buff *skb, u8 *head,
                        int mlen, int plen, int offset, int type)
{
        struct sk_buff *frag;
        int hlen;

        hlen = (type == LOWPAN_DISPATCH_FRAG1) ?
                        LOWPAN_FRAG1_HEAD_SIZE : LOWPAN_FRAGN_HEAD_SIZE;

        raw_dump_inline(__func__, "6lowpan fragment header", head, hlen);

        frag = netdev_alloc_skb(skb->dev,
                                hlen + mlen + plen + IEEE802154_MFR_SIZE);
        if (!frag)
                return -ENOMEM;

        frag->priority = skb->priority;

        /* copy header, MFR and payload */
        skb_put(frag, mlen);
        skb_copy_to_linear_data(frag, skb_mac_header(skb), mlen);

        skb_put(frag, hlen);
        skb_copy_to_linear_data_offset(frag, mlen, head, hlen);

        skb_put(frag, plen);
        skb_copy_to_linear_data_offset(frag, mlen + hlen,
                                       skb_network_header(skb) + offset, plen);

        raw_dump_table(__func__, " raw fragment dump", frag->data, frag->len);

        return dev_queue_xmit(frag);
}

static int
lowpan_skb_fragmentation(struct sk_buff *skb, struct net_device *dev)
{
        int  err, header_length, payload_length, tag, offset = 0;
        u8 head[5];

        header_length = skb->mac_len;
        payload_length = skb->len - header_length;
        tag = lowpan_dev_info(dev)->fragment_tag++;

        /* first fragment header */
        head[0] = LOWPAN_DISPATCH_FRAG1 | ((payload_length >> 8) & 0x7);
        head[1] = payload_length & 0xff;
        head[2] = tag >> 8;
        head[3] = tag & 0xff;

        err = lowpan_fragment_xmit(skb, head, header_length, LOWPAN_FRAG_SIZE,
                                   0, LOWPAN_DISPATCH_FRAG1);

        if (err) {
                pr_debug("%s unable to send FRAG1 packet (tag: %d)",
                         __func__, tag);
                goto exit;
        }

        offset = LOWPAN_FRAG_SIZE;

        /* next fragment header */
        head[0] &= ~LOWPAN_DISPATCH_FRAG1;
        head[0] |= LOWPAN_DISPATCH_FRAGN;

        while (payload_length - offset > 0) {
                int len = LOWPAN_FRAG_SIZE;

                head[4] = offset / 8;

                if (payload_length - offset < len)
                        len = payload_length - offset;

                err = lowpan_fragment_xmit(skb, head, header_length,
                                           len, offset, LOWPAN_DISPATCH_FRAGN);
                if (err) {
                        pr_debug("%s unable to send a subsequent FRAGN packet "
                                 "(tag: %d, offset: %d", __func__, tag, offset);
                        goto exit;
                }

                offset += len;
        }

exit:
        return err;
}

static netdev_tx_t lowpan_xmit(struct sk_buff *skb, struct net_device *dev)
{
        int err = -1;

        pr_debug("package xmit\n");

        skb->dev = lowpan_dev_info(dev)->real_dev;
        if (skb->dev == NULL) {
                pr_debug("ERROR: no real wpan device found\n");
                goto error;
        }

        /* Send directly if less than the MTU minus the 2 checksum bytes. */
        if (skb->len <= IEEE802154_MTU - IEEE802154_MFR_SIZE) {
                err = dev_queue_xmit(skb);
                goto out;
        }

        pr_debug("frame is too big, fragmentation is needed\n");
        err = lowpan_skb_fragmentation(skb, dev);
error:
        dev_kfree_skb(skb);
out:
        if (err)
                pr_debug("ERROR: xmit failed\n");

        return (err < 0) ? NET_XMIT_DROP : err;
}

static struct wpan_phy *lowpan_get_phy(const struct net_device *dev)
{
        struct net_device *real_dev = lowpan_dev_info(dev)->real_dev;
        return ieee802154_mlme_ops(real_dev)->get_phy(real_dev);
}

static u16 lowpan_get_pan_id(const struct net_device *dev)
{
        struct net_device *real_dev = lowpan_dev_info(dev)->real_dev;
        return ieee802154_mlme_ops(real_dev)->get_pan_id(real_dev);
}

static u16 lowpan_get_short_addr(const struct net_device *dev)
{
        struct net_device *real_dev = lowpan_dev_info(dev)->real_dev;
        return ieee802154_mlme_ops(real_dev)->get_short_addr(real_dev);
}

static u8 lowpan_get_dsn(const struct net_device *dev)
{
        struct net_device *real_dev = lowpan_dev_info(dev)->real_dev;
        return ieee802154_mlme_ops(real_dev)->get_dsn(real_dev);
}

static struct header_ops lowpan_header_ops = {
        .create = lowpan_header_create,
};

static struct lock_class_key lowpan_tx_busylock;
static struct lock_class_key lowpan_netdev_xmit_lock_key;

static void lowpan_set_lockdep_class_one(struct net_device *dev,
                                         struct netdev_queue *txq,
                                         void *_unused)
{
        lockdep_set_class(&txq->_xmit_lock,
                          &lowpan_netdev_xmit_lock_key);
}


static int lowpan_dev_init(struct net_device *dev)
{
        netdev_for_each_tx_queue(dev, lowpan_set_lockdep_class_one, NULL);
        dev->qdisc_tx_busylock = &lowpan_tx_busylock;
        return 0;
}

static const struct net_device_ops lowpan_netdev_ops = {
        .ndo_init               = lowpan_dev_init,
        .ndo_start_xmit         = lowpan_xmit,
        .ndo_set_mac_address    = lowpan_set_address,
};

static struct ieee802154_mlme_ops lowpan_mlme = {
        .get_pan_id = lowpan_get_pan_id,
        .get_phy = lowpan_get_phy,
        .get_short_addr = lowpan_get_short_addr,
        .get_dsn = lowpan_get_dsn,
};

static void lowpan_setup(struct net_device *dev)
{
        dev->addr_len           = IEEE802154_ADDR_LEN;
        memset(dev->broadcast, 0xff, IEEE802154_ADDR_LEN);
        dev->type               = ARPHRD_IEEE802154;
        /* Frame Control + Sequence Number + Address fields + Security Header */
        dev->hard_header_len    = 2 + 1 + 20 + 14;
        dev->needed_tailroom    = 2; /* FCS */
        dev->mtu                = 1281;
        dev->tx_queue_len       = 0;
        dev->flags              = IFF_BROADCAST | IFF_MULTICAST;
        dev->watchdog_timeo     = 0;

        dev->netdev_ops         = &lowpan_netdev_ops;
        dev->header_ops         = &lowpan_header_ops;
        dev->ml_priv            = &lowpan_mlme;
        dev->destructor         = free_netdev;
}

static int lowpan_validate(struct nlattr *tb[], struct nlattr *data[])
{
        if (tb[IFLA_ADDRESS]) {
                if (nla_len(tb[IFLA_ADDRESS]) != IEEE802154_ADDR_LEN)
                        return -EINVAL;
        }
        return 0;
}

static int lowpan_rcv(struct sk_buff *skb, struct net_device *dev,
        struct packet_type *pt, struct net_device *orig_dev)
{
        struct sk_buff *local_skb;

        if (!netif_running(dev))
                goto drop;

        if (dev->type != ARPHRD_IEEE802154)
                goto drop;

        /* check that it's our buffer */
        if (skb->data[0] == LOWPAN_DISPATCH_IPV6) {
                /* Copy the packet so that the IPv6 header is
                 * properly aligned.
                 */
                local_skb = skb_copy_expand(skb, NET_SKB_PAD - 1,
                                            skb_tailroom(skb), GFP_ATOMIC);
                if (!local_skb)
                        goto drop;

                local_skb->protocol = htons(ETH_P_IPV6);
                local_skb->pkt_type = PACKET_HOST;

                /* Pull off the 1-byte of 6lowpan header. */
                skb_pull(local_skb, 1);

                lowpan_give_skb_to_devices(local_skb, NULL);

                kfree_skb(local_skb);
                kfree_skb(skb);
        } else {
                switch (skb->data[0] & 0xe0) {
                case LOWPAN_DISPATCH_IPHC:      /* ipv6 datagram */
                case LOWPAN_DISPATCH_FRAG1:     /* first fragment header */
                case LOWPAN_DISPATCH_FRAGN:     /* next fragments headers */
                        local_skb = skb_clone(skb, GFP_ATOMIC);
                        if (!local_skb)
                                goto drop;
                        process_data(local_skb);

                        kfree_skb(skb);
                        break;
                default:
                        break;
                }
        }

        return NET_RX_SUCCESS;

drop:
        kfree_skb(skb);
        return NET_RX_DROP;
}

static int lowpan_newlink(struct net *src_net, struct net_device *dev,
                          struct nlattr *tb[], struct nlattr *data[])
{
        struct net_device *real_dev;
        struct lowpan_dev_record *entry;

        pr_debug("adding new link\n");

        if (!tb[IFLA_LINK])
                return -EINVAL;
        /* find and hold real wpan device */
        real_dev = dev_get_by_index(src_net, nla_get_u32(tb[IFLA_LINK]));
        if (!real_dev)
                return -ENODEV;
        if (real_dev->type != ARPHRD_IEEE802154) {
                dev_put(real_dev);
                return -EINVAL;
        }

        lowpan_dev_info(dev)->real_dev = real_dev;
        lowpan_dev_info(dev)->fragment_tag = 0;
        mutex_init(&lowpan_dev_info(dev)->dev_list_mtx);

        entry = kzalloc(sizeof(struct lowpan_dev_record), GFP_KERNEL);
        if (!entry) {
                dev_put(real_dev);
                lowpan_dev_info(dev)->real_dev = NULL;
                return -ENOMEM;
        }

        entry->ldev = dev;

        /* Set the lowpan harware address to the wpan hardware address. */
        memcpy(dev->dev_addr, real_dev->dev_addr, IEEE802154_ADDR_LEN);

        mutex_lock(&lowpan_dev_info(dev)->dev_list_mtx);
        INIT_LIST_HEAD(&entry->list);
        list_add_tail(&entry->list, &lowpan_devices);
        mutex_unlock(&lowpan_dev_info(dev)->dev_list_mtx);

        register_netdevice(dev);

        return 0;
}

static void lowpan_dellink(struct net_device *dev, struct list_head *head)
{
        struct lowpan_dev_info *lowpan_dev = lowpan_dev_info(dev);
        struct net_device *real_dev = lowpan_dev->real_dev;
        struct lowpan_dev_record *entry, *tmp;

        ASSERT_RTNL();

        mutex_lock(&lowpan_dev_info(dev)->dev_list_mtx);
        list_for_each_entry_safe(entry, tmp, &lowpan_devices, list) {
                if (entry->ldev == dev) {
                        list_del(&entry->list);
                        kfree(entry);
                }
        }
        mutex_unlock(&lowpan_dev_info(dev)->dev_list_mtx);

        mutex_destroy(&lowpan_dev_info(dev)->dev_list_mtx);

        unregister_netdevice_queue(dev, head);

        dev_put(real_dev);
}

static struct rtnl_link_ops lowpan_link_ops __read_mostly = {
        .kind           = "lowpan",
        .priv_size      = sizeof(struct lowpan_dev_info),
        .setup          = lowpan_setup,
        .newlink        = lowpan_newlink,
        .dellink        = lowpan_dellink,
        .validate       = lowpan_validate,
};

static inline int __init lowpan_netlink_init(void)
{
        return rtnl_link_register(&lowpan_link_ops);
}

static inline void lowpan_netlink_fini(void)
{
        rtnl_link_unregister(&lowpan_link_ops);
}

static int lowpan_device_event(struct notifier_block *unused,
                               unsigned long event, void *ptr)
{
        struct net_device *dev = netdev_notifier_info_to_dev(ptr);
        LIST_HEAD(del_list);
        struct lowpan_dev_record *entry, *tmp;

        if (dev->type != ARPHRD_IEEE802154)
                goto out;

        if (event == NETDEV_UNREGISTER) {
                list_for_each_entry_safe(entry, tmp, &lowpan_devices, list) {
                        if (lowpan_dev_info(entry->ldev)->real_dev == dev)
                                lowpan_dellink(entry->ldev, &del_list);
                }

                unregister_netdevice_many(&del_list);
        }

out:
        return NOTIFY_DONE;
}

static struct notifier_block lowpan_dev_notifier = {
        .notifier_call = lowpan_device_event,
};

static struct packet_type lowpan_packet_type = {
        .type = __constant_htons(ETH_P_IEEE802154),
        .func = lowpan_rcv,
};

static int __init lowpan_init_module(void)
{
        int err = 0;

        err = lowpan_netlink_init();
        if (err < 0)
                goto out;

        dev_add_pack(&lowpan_packet_type);

        err = register_netdevice_notifier(&lowpan_dev_notifier);
        if (err < 0) {
                dev_remove_pack(&lowpan_packet_type);
                lowpan_netlink_fini();
        }
out:
        return err;
}

static void __exit lowpan_cleanup_module(void)
{
        struct lowpan_fragment *frame, *tframe;

        lowpan_netlink_fini();

        dev_remove_pack(&lowpan_packet_type);

        unregister_netdevice_notifier(&lowpan_dev_notifier);

        /* Now 6lowpan packet_type is removed, so no new fragments are
         * expected on RX, therefore that's the time to clean incomplete
         * fragments.
         */
        spin_lock_bh(&flist_lock);
        list_for_each_entry_safe(frame, tframe, &lowpan_fragments, list) {
                del_timer_sync(&frame->timer);
                list_del(&frame->list);
                dev_kfree_skb(frame->skb);
                kfree(frame);
        }
        spin_unlock_bh(&flist_lock);
}

module_init(lowpan_init_module);
module_exit(lowpan_cleanup_module);
MODULE_LICENSE("GPL");
MODULE_ALIAS_RTNL_LINK("lowpan");