Return-Path: Message-Id: <1448967386.3315997.454536553.3B344491@webmail.messagingengine.com> From: Hannes Frederic Sowa To: Alexander Aring , linux-wpan@vger.kernel.org Cc: linux-bluetooth@vger.kernel.org, netdev@vger.kernel.org, kernel@pengutronix.de, mcr@sandelman.ca, lukasz.duda@nordicsemi.no, martin.gergeleit@hs-rm.de, "David S . Miller" , Alexey Kuznetsov , James Morris , Hideaki YOSHIFUJI , Patrick McHardy MIME-Version: 1.0 Content-Type: text/plain Subject: Re: [RFCv3 bluetooth-next 3/4] ipv6: add ipv6_addr_prefix_copy Date: Tue, 01 Dec 2015 11:56:26 +0100 In-Reply-To: <1448796882-316-4-git-send-email-alex.aring@gmail.com> References: <1448796882-316-1-git-send-email-alex.aring@gmail.com> <1448796882-316-4-git-send-email-alex.aring@gmail.com> Sender: linux-wpan-owner@vger.kernel.org List-ID: 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 > Cc: Alexey Kuznetsov > Cc: James Morris > Cc: Hideaki YOSHIFUJI > Cc: Patrick McHardy > Signed-off-by: Alexander Aring > --- > 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