From ea9eb698b2f59e16fbf9f480a9b35ddfb3c3a789 Mon Sep 17 00:00:00 2001 From: Alexander Aring Date: Tue, 11 Aug 2015 21:44:10 +0200 Subject: documentation: networking: add 6lowpan documentation This patch adds a 6lowpan.txt into the networking documentation directory. Currently this documentation describes how the lowpan private data of net devices will be handled. Cc: Jonathan Corbet Cc: linux-doc@vger.kernel.org Suggested-by: Jukka Rissanen Signed-off-by: Alexander Aring Signed-off-by: Marcel Holtmann --- Documentation/networking/6lowpan.txt | 50 ++++++++++++++++++++++++++++++++++++ 1 file changed, 50 insertions(+) create mode 100644 Documentation/networking/6lowpan.txt (limited to 'Documentation/networking/6lowpan.txt') diff --git a/Documentation/networking/6lowpan.txt b/Documentation/networking/6lowpan.txt new file mode 100644 index 000000000000..a7dc7e939c7a --- /dev/null +++ b/Documentation/networking/6lowpan.txt @@ -0,0 +1,50 @@ + +Netdev private dataroom for 6lowpan interfaces: + +All 6lowpan able net devices, means all interfaces with ARPHRD_6LOWPAN, +must have "struct lowpan_priv" placed at beginning of netdev_priv. + +The priv_size of each interface should be calculate by: + + dev->priv_size = LOWPAN_PRIV_SIZE(LL_6LOWPAN_PRIV_DATA); + +Where LL_PRIV_6LOWPAN_DATA is sizeof linklayer 6lowpan private data struct. +To access the LL_PRIV_6LOWPAN_DATA structure you can cast: + + lowpan_priv(dev)-priv; + +to your LL_6LOWPAN_PRIV_DATA structure. + +Before registering the lowpan netdev interface you must run: + + lowpan_netdev_setup(dev, LOWPAN_LLTYPE_FOOBAR); + +wheres LOWPAN_LLTYPE_FOOBAR is a define for your 6LoWPAN linklayer type of +enum lowpan_lltypes. + +Example to evaluate the private usually you can do: + +static inline sturct lowpan_priv_foobar * +lowpan_foobar_priv(struct net_device *dev) +{ + return (sturct lowpan_priv_foobar *)lowpan_priv(dev)->priv; +} + +switch (dev->type) { +case ARPHRD_6LOWPAN: + lowpan_priv = lowpan_priv(dev); + /* do great stuff which is ARPHRD_6LOWPAN related */ + switch (lowpan_priv->lltype) { + case LOWPAN_LLTYPE_FOOBAR: + /* do 802.15.4 6LoWPAN handling here */ + lowpan_foobar_priv(dev)->bar = foo; + break; + ... + } + break; +... +} + +In case of generic 6lowpan branch ("net/6lowpan") you can remove the check +on ARPHRD_6LOWPAN, because you can be sure that these function are called +by ARPHRD_6LOWPAN interfaces. -- cgit v1.2.3-59-g8ed1b