1 .. SPDX-License-Identifier: GPL-2.0
2
3 ==============================================
4 Netdev private dataroom for 6lowpan interfaces
5 ==============================================
6
7 All 6lowpan able net devices, means all interfaces with ARPHRD_6LOWPAN,
8 must have "struct lowpan_priv" placed at beginning of netdev_priv.
9
10 The priv_size of each interface should be calculate by::
11
12 dev->priv_size = LOWPAN_PRIV_SIZE(LL_6LOWPAN_PRIV_DATA);
13
14 Where LL_PRIV_6LOWPAN_DATA is sizeof linklayer 6lowpan private data struct.
15 To access the LL_PRIV_6LOWPAN_DATA structure you can cast::
16
17 lowpan_priv(dev)-priv;
18
19 to your LL_6LOWPAN_PRIV_DATA structure.
20
21 Before registering the lowpan netdev interface you must run::
22
23 lowpan_netdev_setup(dev, LOWPAN_LLTYPE_FOOBAR);
24
25 wheres LOWPAN_LLTYPE_FOOBAR is a define for your 6LoWPAN linklayer type of
26 enum lowpan_lltypes.
27
28 Example to evaluate the private usually you can do::
29
30 static inline struct lowpan_priv_foobar *
31 lowpan_foobar_priv(struct net_device *dev)
32 {
33 return (struct lowpan_priv_foobar *)lowpan_priv(dev)->priv;
34 }
35
36 switch (dev->type) {
37 case ARPHRD_6LOWPAN:
38 lowpan_priv = lowpan_priv(dev);
39 /* do great stuff which is ARPHRD_6LOWPAN related */
40 switch (lowpan_priv->lltype) {
41 case LOWPAN_LLTYPE_FOOBAR:
42 /* do 802.15.4 6LoWPAN handling here */
43 lowpan_foobar_priv(dev)->bar = foo;
44 break;
45 ...
46 }
47 break;
48 ...
49 }
50
51 In case of generic 6lowpan branch ("net/6lowpan") you can remove the check
52 on ARPHRD_6LOWPAN, because you can be sure that these function are called
53 by ARPHRD_6LOWPAN interfaces.
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