Hi,
On 05/02/2016 08:59 PM, Hannes Frederic Sowa wrote:
> Hello,
>
> On 20.04.2016 10:19, Alexander Aring wrote:
>> This patch will introduce a 6lowpan neighbour private data. Like the
>> interface private data we handle private data for generic 6lowpan and
>> for link-layer specific 6lowpan.
>>
>> The current first use case if to save the short address for a 802.15.4
>> 6lowpan neighbour.
>>
>> Cc: David S. Miller <da...@davemloft.net>
>> Signed-off-by: Alexander Aring <a...@pengutronix.de>
>> ---
>> include/linux/netdevice.h | 3 +--
>> include/net/6lowpan.h | 24 ++++++++++++++++++++++++
>> net/bluetooth/6lowpan.c | 2 ++
>> net/ieee802154/6lowpan/core.c | 12 ++++++++++++
>> 4 files changed, 39 insertions(+), 2 deletions(-)
>>
>> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
>> index 166402a..0052c42 100644
>> --- a/include/linux/netdevice.h
>> +++ b/include/linux/netdevice.h
>> @@ -1487,8 +1487,7 @@ enum netdev_priv_flags {
>> * @perm_addr: Permanent hw address
>> * @addr_assign_type: Hw address assignment type
>> * @addr_len: Hardware address length
>> - * @neigh_priv_len; Used in neigh_alloc(),
>> - * initialized only in atm/clip.c
>> + * @neigh_priv_len; Used in neigh_alloc()
>> * @dev_id: Used to differentiate devices that share
>> * the same link layer address
>> * @dev_port: Used to differentiate devices that share
>> diff --git a/include/net/6lowpan.h b/include/net/6lowpan.h
>> index da84cf9..61c6517 100644
>> --- a/include/net/6lowpan.h
>> +++ b/include/net/6lowpan.h
>> @@ -98,6 +98,9 @@ static inline bool lowpan_is_iphc(u8 dispatch)
>> #define LOWPAN_PRIV_SIZE(llpriv_size) \
>> (sizeof(struct lowpan_dev) + llpriv_size)
>>
>> +#define LOWPAN_NEIGH_PRIV_SIZE(llneigh_priv_size) \
>> + (sizeof(struct lowpan_neigh) + llneigh_priv_size)
>> +
>> enum lowpan_lltypes {
>> LOWPAN_LLTYPE_BTLE,
>> LOWPAN_LLTYPE_IEEE802154,
>> @@ -141,6 +144,27 @@ struct lowpan_dev {
>> u8 priv[0] __aligned(sizeof(void *));
>> };
>>
>> +struct lowpan_neigh {
>> + /* 6LoWPAN neigh private data */
>> + /* must be last */
>> + u8 priv[0] __aligned(sizeof(void *));
>
> Are you sure this declaration is correct? You take its size above, which
> should result in zero. Looks a little bit strange. :)
>
I think yes it's correct, but I will remove it.
The basic idea here is to introduce a 6LoWPAN neighbour private data and
Link-Layer specific neighbour private data.
Example:
6LoWPAN neighbour data:
The GHC capability, 6LoWPAN contains some compression methods, also for
several Next Header (UDP, IPv6 extension headers, ...). So far I
understand each neighbour can tell which compression method it supports
by a special option field, see [0].
Such data doesn't depends on Link-Layer and is the same for all 6LoWPAN
over FOO standards.
6LoWPAN Link-Layer specific neighbour data:
Like the short address handling in case of 6LoWPAN over 802.15.4.
>> +};
>> +
>> +struct lowpan_802154_neigh {
>> + __le16 short_addr;
>> +};
>> +
>> +static inline struct lowpan_neigh *lowpan_neigh(void *neigh_priv)
>> +{
>> + return neigh_priv;
>> +}
>> +
>> +static inline
>> +struct lowpan_802154_neigh *lowpan_802154_neigh(void *neigh_priv)
>> +{
>> + return (struct lowpan_802154_neigh *)lowpan_neigh(neigh_priv)->priv;
>> +}
>
> Can't you remove lowpan_neigh completely and just use 802154_neigh at
> this point?
Yes, I remove it. I think to introduce such layer for 6LoWPAN neighbour
data, we can still introduce it later when we have an use-case. Also with
a better foo_ops structure so we have something like this:
6lowpan interface:
- .ndo_neigh_construct
- "doing 6lowpan stuff"
- .ndo_ll_neigh_construct
- "doing ll 6lowpan stuff"
and ".ndo_ll_neigh_construct" differs in case of 6lowpan ll
implementation (802.15.4 or BTLE currently).
- Alex
[0] https://tools.ietf.org/html/rfc7400#section-3.3
