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
56static int open_count;
57
58static const struct header_ops lowpan_header_ops = {
59	.create	= lowpan_header_create,
60};
61
62static int lowpan_dev_init(struct net_device *ldev)
63{
64	netdev_lockdep_set_classes(ldev);
65
66	return 0;
67}
68
69static int lowpan_open(struct net_device *dev)
70{
71	if (!open_count)
72		lowpan_rx_init();
73	open_count++;
74	return 0;
75}
76
77static int lowpan_stop(struct net_device *dev)
78{
79	open_count--;
80	if (!open_count)
81		lowpan_rx_exit();
82	return 0;
83}
84
85static 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
94static int lowpan_get_iflink(const struct net_device *dev)
95{
96	return READ_ONCE(lowpan_802154_dev(dev)->wdev->ifindex);
97}
98
99static 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
108static 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->features		|= NETIF_F_NETNS_LOCAL;
120}
121
122static 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
132static 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
184static 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
195static 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
204static inline int __init lowpan_netlink_init(void)
205{
206	return rtnl_link_register(&lowpan_link_ops);
207}
208
209static inline void lowpan_netlink_fini(void)
210{
211	rtnl_link_unregister(&lowpan_link_ops);
212}
213
214static 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
242static struct notifier_block lowpan_dev_notifier = {
243	.notifier_call = lowpan_device_event,
244};
245
246static 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
264out_pack:
265	lowpan_netlink_fini();
266out_frag:
267	lowpan_net_frag_exit();
268out:
269	return err;
270}
271
272static 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
281module_init(lowpan_init_module);
282module_exit(lowpan_cleanup_module);
283MODULE_DESCRIPTION("IPv6 over Low power Wireless Personal Area Network IEEE 802.15.4 core");
284MODULE_LICENSE("GPL");
285MODULE_ALIAS_RTNL_LINK("lowpan");
286