net/ieee802154/6lowpan/core.c

   1 /* Copyright 2011, Siemens AG
   2  * written by Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
   3  */
   4
   5 /* Based on patches from Jon Smirl <jonsmirl@gmail.com>
   6  * Copyright (c) 2011 Jon Smirl <jonsmirl@gmail.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2
  10  * as published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  */
  17
  18 /* Jon's code is based on 6lowpan implementation for Contiki which is:
  19  * Copyright (c) 2008, Swedish Institute of Computer Science.
  20  * All rights reserved.
  21  *
  22  * Redistribution and use in source and binary forms, with or without
  23  * modification, are permitted provided that the following conditions
  24  * are met:
  25  * 1. Redistributions of source code must retain the above copyright
  26  *    notice, this list of conditions and the following disclaimer.
  27  * 2. Redistributions in binary form must reproduce the above copyright
  28  *    notice, this list of conditions and the following disclaimer in the
  29  *    documentation and/or other materials provided with the distribution.
  30  * 3. Neither the name of the Institute nor the names of its contributors
  31  *    may be used to endorse or promote products derived from this software
  32  *    without specific prior written permission.
  33  *
  34  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  35  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  36  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  37  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  38  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  39  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  40  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  41  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  42  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  43  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  44  * SUCH DAMAGE.
  45  */
  46
  47 #include <linux/module.h>
  48 #include <linux/netdevice.h>
  49 #include <linux/ieee802154.h>
  50 #include <linux/if_arp.h>
  51
  52 #include <net/ipv6.h>
  53
  54 #include "6lowpan_i.h"
  55
  56 static int open_count;
  57
  58 static const struct header_ops lowpan_header_ops = {
  59         .create = lowpan_header_create,
  60 };
  61
  62 static int lowpan_dev_init(struct net_device *ldev)
  63 {
  64         netdev_lockdep_set_classes(ldev);
  65
  66         return 0;
  67 }
  68
  69 static int lowpan_open(struct net_device *dev)
  70 {
  71         if (!open_count)
  72                 lowpan_rx_init();
  73         open_count++;
  74         return 0;
  75 }
  76
  77 static int lowpan_stop(struct net_device *dev)
  78 {
  79         open_count--;
  80         if (!open_count)
  81                 lowpan_rx_exit();
  82         return 0;
  83 }
  84
  85 static int lowpan_neigh_construct(struct net_device *dev, struct neighbour *n)
  86 {
  87         struct lowpan_802154_neigh *neigh = lowpan_802154_neigh(neighbour_priv(n));
  88
  89         /* default no short_addr is available for a neighbour */
  90         neigh->short_addr = cpu_to_le16(IEEE802154_ADDR_SHORT_UNSPEC);
  91         return 0;
  92 }
  93
  94 static int lowpan_get_iflink(const struct net_device *dev)
  95 {
  96         return READ_ONCE(lowpan_802154_dev(dev)->wdev->ifindex);
  97 }
  98
  99 static const struct net_device_ops lowpan_netdev_ops = {
 100         .ndo_init               = lowpan_dev_init,
 101         .ndo_start_xmit         = lowpan_xmit,
 102         .ndo_open               = lowpan_open,
 103         .ndo_stop               = lowpan_stop,
 104         .ndo_neigh_construct    = lowpan_neigh_construct,
 105         .ndo_get_iflink         = lowpan_get_iflink,
 106 };
 107
 108 static void lowpan_setup(struct net_device *ldev)
 109 {
 110         memset(ldev->broadcast, 0xff, IEEE802154_ADDR_LEN);
 111         /* We need an ipv6hdr as minimum len when calling xmit */
 112         ldev->hard_header_len   = sizeof(struct ipv6hdr);
 113         ldev->flags             = IFF_BROADCAST | IFF_MULTICAST;
 114         ldev->priv_flags        |= IFF_NO_QUEUE;
 115
 116         ldev->netdev_ops        = &lowpan_netdev_ops;
 117         ldev->header_ops        = &lowpan_header_ops;
 118         ldev->needs_free_netdev = true;
 119         ldev->netns_local       = true;
 120 }
 121
 122 static int lowpan_validate(struct nlattr *tb[], struct nlattr *data[],
 123                            struct netlink_ext_ack *extack)
 124 {
 125         if (tb[IFLA_ADDRESS]) {
 126                 if (nla_len(tb[IFLA_ADDRESS]) != IEEE802154_ADDR_LEN)
 127                         return -EINVAL;
 128         }
 129         return 0;
 130 }
 131
 132 static int lowpan_newlink(struct net *src_net, struct net_device *ldev,
 133                           struct nlattr *tb[], struct nlattr *data[],
 134                           struct netlink_ext_ack *extack)
 135 {
 136         struct net_device *wdev;
 137         int ret;
 138
 139         ASSERT_RTNL();
 140
 141         pr_debug("adding new link\n");
 142
 143         if (!tb[IFLA_LINK])
 144                 return -EINVAL;
 145         /* find and hold wpan device */
 146         wdev = dev_get_by_index(dev_net(ldev), nla_get_u32(tb[IFLA_LINK]));
 147         if (!wdev)
 148                 return -ENODEV;
 149         if (wdev->type != ARPHRD_IEEE802154) {
 150                 dev_put(wdev);
 151                 return -EINVAL;
 152         }
 153
 154         if (wdev->ieee802154_ptr->lowpan_dev) {
 155                 dev_put(wdev);
 156                 return -EBUSY;
 157         }
 158
 159         lowpan_802154_dev(ldev)->wdev = wdev;
 160         /* Set the lowpan hardware address to the wpan hardware address. */
 161         __dev_addr_set(ldev, wdev->dev_addr, IEEE802154_ADDR_LEN);
 162         /* We need headroom for possible wpan_dev_hard_header call and tailroom
 163          * for encryption/fcs handling. The lowpan interface will replace
 164          * the IPv6 header with 6LoWPAN header. At worst case the 6LoWPAN
 165          * header has LOWPAN_IPHC_MAX_HEADER_LEN more bytes than the IPv6
 166          * header.
 167          */
 168         ldev->needed_headroom = LOWPAN_IPHC_MAX_HEADER_LEN +
 169                                 wdev->needed_headroom;
 170         ldev->needed_tailroom = wdev->needed_tailroom;
 171
 172         ldev->neigh_priv_len = sizeof(struct lowpan_802154_neigh);
 173
 174         ret = lowpan_register_netdevice(ldev, LOWPAN_LLTYPE_IEEE802154);
 175         if (ret < 0) {
 176                 dev_put(wdev);
 177                 return ret;
 178         }
 179
 180         wdev->ieee802154_ptr->lowpan_dev = ldev;
 181         return 0;
 182 }
 183
 184 static void lowpan_dellink(struct net_device *ldev, struct list_head *head)
 185 {
 186         struct net_device *wdev = lowpan_802154_dev(ldev)->wdev;
 187
 188         ASSERT_RTNL();
 189
 190         wdev->ieee802154_ptr->lowpan_dev = NULL;
 191         lowpan_unregister_netdevice(ldev);
 192         dev_put(wdev);
 193 }
 194
 195 static struct rtnl_link_ops lowpan_link_ops __read_mostly = {
 196         .kind           = "lowpan",
 197         .priv_size      = LOWPAN_PRIV_SIZE(sizeof(struct lowpan_802154_dev)),
 198         .setup          = lowpan_setup,
 199         .newlink        = lowpan_newlink,
 200         .dellink        = lowpan_dellink,
 201         .validate       = lowpan_validate,
 202 };
 203
 204 static inline int __init lowpan_netlink_init(void)
 205 {
 206         return rtnl_link_register(&lowpan_link_ops);
 207 }
 208
 209 static inline void lowpan_netlink_fini(void)
 210 {
 211         rtnl_link_unregister(&lowpan_link_ops);
 212 }
 213
 214 static int lowpan_device_event(struct notifier_block *unused,
 215                                unsigned long event, void *ptr)
 216 {
 217         struct net_device *ndev = netdev_notifier_info_to_dev(ptr);
 218         struct wpan_dev *wpan_dev;
 219
 220         if (ndev->type != ARPHRD_IEEE802154)
 221                 return NOTIFY_DONE;
 222         wpan_dev = ndev->ieee802154_ptr;
 223         if (!wpan_dev)
 224                 return NOTIFY_DONE;
 225
 226         switch (event) {
 227         case NETDEV_UNREGISTER:
 228                 /* Check if wpan interface is unregistered that we
 229                  * also delete possible lowpan interfaces which belongs
 230                  * to the wpan interface.
 231                  */
 232                 if (wpan_dev->lowpan_dev)
 233                         lowpan_dellink(wpan_dev->lowpan_dev, NULL);
 234                 break;
 235         default:
 236                 return NOTIFY_DONE;
 237         }
 238
 239         return NOTIFY_OK;
 240 }
 241
 242 static struct notifier_block lowpan_dev_notifier = {
 243         .notifier_call = lowpan_device_event,
 244 };
 245
 246 static int __init lowpan_init_module(void)
 247 {
 248         int err = 0;
 249
 250         err = lowpan_net_frag_init();
 251         if (err < 0)
 252                 goto out;
 253
 254         err = lowpan_netlink_init();
 255         if (err < 0)
 256                 goto out_frag;
 257
 258         err = register_netdevice_notifier(&lowpan_dev_notifier);
 259         if (err < 0)
 260                 goto out_pack;
 261
 262         return 0;
 263
 264 out_pack:
 265         lowpan_netlink_fini();
 266 out_frag:
 267         lowpan_net_frag_exit();
 268 out:
 269         return err;
 270 }
 271
 272 static void __exit lowpan_cleanup_module(void)
 273 {
 274         lowpan_netlink_fini();
 275
 276         lowpan_net_frag_exit();
 277
 278         unregister_netdevice_notifier(&lowpan_dev_notifier);
 279 }
 280
 281 module_init(lowpan_init_module);
 282 module_exit(lowpan_cleanup_module);
 283 MODULE_DESCRIPTION("IPv6 over Low power Wireless Personal Area Network IEEE 802.15.4 core");
 284 MODULE_LICENSE("GPL");
 285 MODULE_ALIAS_RTNL_LINK("lowpan");