Return-Path: From: Alexander Aring To: 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, Alexander Aring , "David S . Miller" , Alexey Kuznetsov , James Morris , Hideaki YOSHIFUJI , Patrick McHardy Subject: [RFCv3 bluetooth-next 3/4] ipv6: add ipv6_addr_prefix_copy Date: Sun, 29 Nov 2015 12:34:41 +0100 Message-Id: <1448796882-316-4-git-send-email-alex.aring@gmail.com> In-Reply-To: <1448796882-316-1-git-send-email-alex.aring@gmail.com> References: <1448796882-316-1-git-send-email-alex.aring@gmail.com> Sender: linux-bluetooth-owner@vger.kernel.org List-ID: 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)); + } +} + static inline void __ipv6_addr_set_half(__be32 *addr, __be32 wh, __be32 wl) { -- 2.6.1