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#include <net/netdev_lock.h>
 54
 55#include "6lowpan_i.h"
 56
 57static int open_count;
 58
 59static const struct header_ops lowpan_header_ops = {
 60	.create	= lowpan_header_create,
 61};
 62
 63static int lowpan_dev_init(struct net_device *ldev)
 64{
 65	netdev_lockdep_set_classes(ldev);
 66
 67	return 0;
 68}
 69
 70static int lowpan_open(struct net_device *dev)
 71{
 72	if (!open_count)
 73		lowpan_rx_init();
 74	open_count++;
 75	return 0;
 76}
 77
 78static int lowpan_stop(struct net_device *dev)
 79{
 80	open_count--;
 81	if (!open_count)
 82		lowpan_rx_exit();
 83	return 0;
 84}
 85
 86static int lowpan_neigh_construct(struct net_device *dev, struct neighbour *n)
 87{
 88	struct lowpan_802154_neigh *neigh = lowpan_802154_neigh(neighbour_priv(n));
 89
 90	/* default no short_addr is available for a neighbour */
 91	neigh->short_addr = cpu_to_le16(IEEE802154_ADDR_SHORT_UNSPEC);
 92	return 0;
 93}
 94
 95static int lowpan_get_iflink(const struct net_device *dev)
 96{
 97	return READ_ONCE(lowpan_802154_dev(dev)->wdev->ifindex);
 98}
 99
100static const struct net_device_ops lowpan_netdev_ops = {
101	.ndo_init		= lowpan_dev_init,
102	.ndo_start_xmit		= lowpan_xmit,
103	.ndo_open		= lowpan_open,
104	.ndo_stop		= lowpan_stop,
105	.ndo_neigh_construct    = lowpan_neigh_construct,
106	.ndo_get_iflink         = lowpan_get_iflink,
107};
108
109static void lowpan_setup(struct net_device *ldev)
110{
111	memset(ldev->broadcast, 0xff, IEEE802154_ADDR_LEN);
112	/* We need an ipv6hdr as minimum len when calling xmit */
113	ldev->hard_header_len	= sizeof(struct ipv6hdr);
114	ldev->flags		= IFF_BROADCAST | IFF_MULTICAST;
115	ldev->priv_flags	|= IFF_NO_QUEUE;
116
117	ldev->netdev_ops	= &lowpan_netdev_ops;
118	ldev->header_ops	= &lowpan_header_ops;
119	ldev->needs_free_netdev	= true;
120	ldev->netns_immutable	= true;
121}
122
123static int lowpan_validate(struct nlattr *tb[], struct nlattr *data[],
124			   struct netlink_ext_ack *extack)
125{
126	if (tb[IFLA_ADDRESS]) {
127		if (nla_len(tb[IFLA_ADDRESS]) != IEEE802154_ADDR_LEN)
128			return -EINVAL;
129	}
130	return 0;
131}
132
133static int lowpan_newlink(struct net_device *ldev,
134			  struct rtnl_newlink_params *params,
135			  struct netlink_ext_ack *extack)
136{
137	struct nlattr **tb = params->tb;
138	struct net_device *wdev;
139	int ret;
140
141	ASSERT_RTNL();
142
143	pr_debug("adding new link\n");
144
145	if (!tb[IFLA_LINK])
146		return -EINVAL;
147	if (params->link_net && !net_eq(params->link_net, dev_net(ldev)))
148		return -EINVAL;
149	/* find and hold wpan device */
150	wdev = dev_get_by_index(dev_net(ldev), nla_get_u32(tb[IFLA_LINK]));
151	if (!wdev)
152		return -ENODEV;
153	if (wdev->type != ARPHRD_IEEE802154) {
154		dev_put(wdev);
155		return -EINVAL;
156	}
157
158	if (wdev->ieee802154_ptr->lowpan_dev) {
159		dev_put(wdev);
160		return -EBUSY;
161	}
162
163	lowpan_802154_dev(ldev)->wdev = wdev;
164	/* Set the lowpan hardware address to the wpan hardware address. */
165	__dev_addr_set(ldev, wdev->dev_addr, IEEE802154_ADDR_LEN);
166	/* We need headroom for possible wpan_dev_hard_header call and tailroom
167	 * for encryption/fcs handling. The lowpan interface will replace
168	 * the IPv6 header with 6LoWPAN header. At worst case the 6LoWPAN
169	 * header has LOWPAN_IPHC_MAX_HEADER_LEN more bytes than the IPv6
170	 * header.
171	 */
172	ldev->needed_headroom = LOWPAN_IPHC_MAX_HEADER_LEN +
173				wdev->needed_headroom;
174	ldev->needed_tailroom = wdev->needed_tailroom;
175
176	ldev->neigh_priv_len = sizeof(struct lowpan_802154_neigh);
177
178	ret = lowpan_register_netdevice(ldev, LOWPAN_LLTYPE_IEEE802154);
179	if (ret < 0) {
180		dev_put(wdev);
181		return ret;
182	}
183
184	wdev->ieee802154_ptr->lowpan_dev = ldev;
185	return 0;
186}
187
188static void lowpan_dellink(struct net_device *ldev, struct list_head *head)
189{
190	struct net_device *wdev = lowpan_802154_dev(ldev)->wdev;
191
192	ASSERT_RTNL();
193
194	wdev->ieee802154_ptr->lowpan_dev = NULL;
195	lowpan_unregister_netdevice(ldev);
196	dev_put(wdev);
197}
198
199static struct rtnl_link_ops lowpan_link_ops __read_mostly = {
200	.kind		= "lowpan",
201	.priv_size	= LOWPAN_PRIV_SIZE(sizeof(struct lowpan_802154_dev)),
202	.setup		= lowpan_setup,
203	.newlink	= lowpan_newlink,
204	.dellink	= lowpan_dellink,
205	.validate	= lowpan_validate,
206};
207
208static inline int __init lowpan_netlink_init(void)
209{
210	return rtnl_link_register(&lowpan_link_ops);
211}
212
213static inline void lowpan_netlink_fini(void)
214{
215	rtnl_link_unregister(&lowpan_link_ops);
216}
217
218static int lowpan_device_event(struct notifier_block *unused,
219			       unsigned long event, void *ptr)
220{
221	struct net_device *ndev = netdev_notifier_info_to_dev(ptr);
222	struct wpan_dev *wpan_dev;
223
224	if (ndev->type != ARPHRD_IEEE802154)
225		return NOTIFY_DONE;
226	wpan_dev = ndev->ieee802154_ptr;
227	if (!wpan_dev)
228		return NOTIFY_DONE;
229
230	switch (event) {
231	case NETDEV_UNREGISTER:
232		/* Check if wpan interface is unregistered that we
233		 * also delete possible lowpan interfaces which belongs
234		 * to the wpan interface.
235		 */
236		if (wpan_dev->lowpan_dev)
237			lowpan_dellink(wpan_dev->lowpan_dev, NULL);
238		break;
239	default:
240		return NOTIFY_DONE;
241	}
242
243	return NOTIFY_OK;
244}
245
246static struct notifier_block lowpan_dev_notifier = {
247	.notifier_call = lowpan_device_event,
248};
249
250static int __init lowpan_init_module(void)
251{
252	int err = 0;
253
254	err = lowpan_net_frag_init();
255	if (err < 0)
256		goto out;
257
258	err = lowpan_netlink_init();
259	if (err < 0)
260		goto out_frag;
261
262	err = register_netdevice_notifier(&lowpan_dev_notifier);
263	if (err < 0)
264		goto out_pack;
265
266	return 0;
267
268out_pack:
269	lowpan_netlink_fini();
270out_frag:
271	lowpan_net_frag_exit();
272out:
273	return err;
274}
275
276static void __exit lowpan_cleanup_module(void)
277{
278	lowpan_netlink_fini();
279
280	lowpan_net_frag_exit();
281
282	unregister_netdevice_notifier(&lowpan_dev_notifier);
283}
284
285module_init(lowpan_init_module);
286module_exit(lowpan_cleanup_module);
287MODULE_DESCRIPTION("IPv6 over Low power Wireless Personal Area Network IEEE 802.15.4 core");
288MODULE_LICENSE("GPL");
289MODULE_ALIAS_RTNL_LINK("lowpan");