xref: /linux/net/ieee802154/6lowpan/core.c (revision 9410645520e9b820069761f3450ef6661418e279)
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 
lowpan_dev_init(struct net_device * ldev)62 static int lowpan_dev_init(struct net_device *ldev)
63 {
64 	netdev_lockdep_set_classes(ldev);
65 
66 	return 0;
67 }
68 
lowpan_open(struct net_device * dev)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 
lowpan_stop(struct net_device * dev)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 
lowpan_neigh_construct(struct net_device * dev,struct neighbour * n)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 
lowpan_get_iflink(const struct net_device * dev)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 
lowpan_setup(struct net_device * ldev)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 
lowpan_validate(struct nlattr * tb[],struct nlattr * data[],struct netlink_ext_ack * extack)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 
lowpan_newlink(struct net * src_net,struct net_device * ldev,struct nlattr * tb[],struct nlattr * data[],struct netlink_ext_ack * extack)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 
lowpan_dellink(struct net_device * ldev,struct list_head * head)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 
lowpan_netlink_init(void)204 static inline int __init lowpan_netlink_init(void)
205 {
206 	return rtnl_link_register(&lowpan_link_ops);
207 }
208 
lowpan_netlink_fini(void)209 static inline void lowpan_netlink_fini(void)
210 {
211 	rtnl_link_unregister(&lowpan_link_ops);
212 }
213 
lowpan_device_event(struct notifier_block * unused,unsigned long event,void * ptr)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 
lowpan_init_module(void)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 
lowpan_cleanup_module(void)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");
286