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[deliverable/linux.git] / net / ieee802154 / 6lowpan_rtnl.c

/* 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.
 */

/* 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/6lowpan.h>
#include <net/ipv6.h>

#include "reassembly.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 */
        __be16                  fragment_tag;
};

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

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.mode = IEEE802154_ADDR_LONG;
        sa.pan_id = ieee802154_mlme_ops(dev)->get_pan_id(dev);
        sa.extended_addr = ieee802154_devaddr_from_raw(saddr);

        /* intra-PAN communications */
        da.pan_id = sa.pan_id;

        /* if the destination address is the broadcast address, use the
         * corresponding short address
         */
        if (lowpan_is_addr_broadcast(daddr)) {
                da.mode = IEEE802154_ADDR_SHORT;
                da.short_addr = cpu_to_le16(IEEE802154_ADDR_BROADCAST);
        } else {
                da.mode = IEEE802154_ADDR_LONG;
                da.extended_addr = ieee802154_devaddr_from_raw(daddr);

                /* 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, 0);
}

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 int process_data(struct sk_buff *skb, const struct ieee802154_hdr *hdr)
{
        u8 iphc0, iphc1;
        struct ieee802154_addr_sa sa, da;
        void *sap, *dap;

        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;

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

        ieee802154_addr_to_sa(&sa, &hdr->source);
        ieee802154_addr_to_sa(&da, &hdr->dest);

        if (sa.addr_type == IEEE802154_ADDR_SHORT)
                sap = &sa.short_addr;
        else
                sap = &sa.hwaddr;

        if (da.addr_type == IEEE802154_ADDR_SHORT)
                dap = &da.short_addr;
        else
                dap = &da.hwaddr;

        return lowpan_process_data(skb, skb->dev, sap, sa.addr_type,
                                   IEEE802154_ADDR_LEN, dap, da.addr_type,
                                   IEEE802154_ADDR_LEN, iphc0, iphc1,
                                   lowpan_give_skb_to_devices);

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;
        u16 dgram_offset, dgram_size, payload_length, header_length,
            lowpan_size, frag_plen, offset;
        __be16 tag;
        u8 head[5];

        header_length = skb->mac_len;
        payload_length = skb->len - header_length;
        tag = lowpan_dev_info(dev)->fragment_tag++;
        lowpan_size = skb_network_header_len(skb);
        dgram_size = lowpan_uncompress_size(skb, &dgram_offset) -
                     header_length;

        /* first fragment header */
        head[0] = LOWPAN_DISPATCH_FRAG1 | ((dgram_size >> 8) & 0x7);
        head[1] = dgram_size & 0xff;
        memcpy(head + 2, &tag, sizeof(tag));

        /* calc the nearest payload length(divided to 8) for first fragment
         * which fits into a IEEE802154_MTU
         */
        frag_plen = round_down(IEEE802154_MTU - header_length -
                               LOWPAN_FRAG1_HEAD_SIZE - lowpan_size -
                               IEEE802154_MFR_SIZE, 8);

        err = lowpan_fragment_xmit(skb, head, header_length,
                                   frag_plen + lowpan_size, 0,
                                   LOWPAN_DISPATCH_FRAG1);
        if (err) {
                pr_debug("%s unable to send FRAG1 packet (tag: %d)",
                         __func__, tag);
                goto exit;
        }

        offset = lowpan_size + frag_plen;
        dgram_offset += frag_plen;

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

        frag_plen = round_down(IEEE802154_MTU - header_length -
                               LOWPAN_FRAGN_HEAD_SIZE - IEEE802154_MFR_SIZE, 8);

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

                head[4] = dgram_offset >> 3;

                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 FRAGN packet. (tag: %d, offset: %d)\n",
                                 __func__, tag, offset);
                        goto exit;
                }

                offset += len;
                dgram_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 __le16 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 __le16 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 ieee802154_hdr hdr;
        int ret;

        skb = skb_share_check(skb, GFP_ATOMIC);
        if (!skb)
                goto drop;

        if (!netif_running(dev))
                goto drop_skb;

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

        if (ieee802154_hdr_peek_addrs(skb, &hdr) < 0)
                goto drop_skb;

        /* check that it's our buffer */
        if (skb->data[0] == LOWPAN_DISPATCH_IPV6) {
                skb->protocol = htons(ETH_P_IPV6);
                skb->pkt_type = PACKET_HOST;

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

                ret = lowpan_give_skb_to_devices(skb, NULL);
                if (ret == NET_RX_DROP)
                        goto drop;
        } else {
                switch (skb->data[0] & 0xe0) {
                case LOWPAN_DISPATCH_IPHC:      /* ipv6 datagram */
                        ret = process_data(skb, &hdr);
                        if (ret == NET_RX_DROP)
                                goto drop;
                        break;
                case LOWPAN_DISPATCH_FRAG1:     /* first fragment header */
                        ret = lowpan_frag_rcv(skb, LOWPAN_DISPATCH_FRAG1);
                        if (ret == 1) {
                                ret = process_data(skb, &hdr);
                                if (ret == NET_RX_DROP)
                                        goto drop;
                        }
                        break;
                case LOWPAN_DISPATCH_FRAGN:     /* next fragments headers */
                        ret = lowpan_frag_rcv(skb, LOWPAN_DISPATCH_FRAGN);
                        if (ret == 1) {
                                ret = process_data(skb, &hdr);
                                if (ret == NET_RX_DROP)
                                        goto drop;
                        }
                        break;
                default:
                        break;
                }
        }

        return NET_RX_SUCCESS;
drop_skb:
        kfree_skb(skb);
drop:
        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;
        mutex_init(&lowpan_dev_info(dev)->dev_list_mtx);

        entry = kzalloc(sizeof(*entry), 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 = htons(ETH_P_IEEE802154),
        .func = lowpan_rcv,
};

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

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

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

        dev_add_pack(&lowpan_packet_type);

        err = register_netdevice_notifier(&lowpan_dev_notifier);
        if (err < 0)
                goto out_pack;

        return 0;

out_pack:
        dev_remove_pack(&lowpan_packet_type);
        lowpan_netlink_fini();
out_frag:
        lowpan_net_frag_exit();
out:
        return err;
}

static void __exit lowpan_cleanup_module(void)
{
        lowpan_netlink_fini();

        dev_remove_pack(&lowpan_packet_type);

        lowpan_net_frag_exit();

        unregister_netdevice_notifier(&lowpan_dev_notifier);
}

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