Hannes Frederic Sowa wrote:
>
>
> On Sun, Nov 29, 2015, at 12:34, Alexander Aring wrote:
>> This patch adds a static inline function ipv6_addr_prefix_copy which
>> copies a ipv6 address prefix(argument pfx) into the ipv6 address prefix.
>> The prefix len is given by plen as bits. This function mainly based on
>> ipv6_addr_prefix which copies one address prefix from address into a new
>> ipv6 address destination and zero all other address bits.
>>
>> The difference is that ipv6_addr_prefix_copy don't get a prefix from an
>> ipv6 address, it sets a prefix to an ipv6 address with keeping other
>> address bits. The use case is for context based address compression
>> inside 6LoWPAN IPHC header which keeping ipv6 prefixes inside a context
>> table to lookup address-bits without sending them.
>>
>> Cc: David S. Miller <da...@davemloft.net>
>> Cc: Alexey Kuznetsov <kuz...@ms2.inr.ac.ru>
>> Cc: James Morris <jmor...@namei.org>
>> Cc: Hideaki YOSHIFUJI <yoshf...@linux-ipv6.org>
>> Cc: Patrick McHardy <ka...@trash.net>
>> Signed-off-by: Alexander Aring <alex.ar...@gmail.com>
>> ---
>> include/net/ipv6.h | 15 +++++++++++++++
>> 1 file changed, 15 insertions(+)
>>
>> diff --git a/include/net/ipv6.h b/include/net/ipv6.h
>> index e1a10b0..cd3881e6 100644
>> --- a/include/net/ipv6.h
>> +++ b/include/net/ipv6.h
>> @@ -382,6 +382,21 @@ static inline void ipv6_addr_prefix(struct in6_addr
>> *pfx,
>> pfx->s6_addr[o] = addr->s6_addr[o] & (0xff00 >> b);
>> }
>>
>> +static inline void ipv6_addr_prefix_copy(struct in6_addr *addr,
>> + const struct in6_addr *pfx,
>> + int plen)
>> +{
>> + /* caller must guarantee 0 <= plen <= 128 */
>> + int o = plen >> 3,
>> + b = plen & 0x7;
>> +
>> + memcpy(addr->s6_addr, pfx, o);
>> + if (b != 0) {
>> + addr->s6_addr[o] &= ~(0xff00 >> b);
>> + addr->s6_addr[o] |= (pfx->s6_addr[o] & (0xff00 >> b));
>> + }
>> +}
>> +
>
> Acked-by: Hannes Frederic Sowa <han...@stressinduktion.org>
Acked-by: YOSHIFUJI Hideaki <yoshf...@linux-ipv6.org>
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--
吉藤英明 <hideaki.yoshif...@miraclelinux.com>
ミラクル・リナックス株式会社 技術本部 サポート部
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