-Convenience script for reference on generating IPv6 ULA (v6 equivalent of v4 10/8, 192.168/16 and 172.16/12 addresses)

git-svn-id: https://svn.code.sf.net/p/xcat/code/xcat-core/trunk@8616 8638fb3e-16cb-4fca-ae20-7b5d299a9bcd

xCAT-server/share/xcat/scripts/genula.sh

@@ -0,0 +1,35 @@
+#!/bin/bash
+# This script will generate an IPv6 ULA.  In IPv6, you know longer get to pick your favorite private network network and go for it,
+# you must accept a psuedorandom /48 out of the fd::/8 space.  This script will generate a /48 for either deploying an isolated
+# ipv6 network that will almost certainly not conflict with present and future upstream ipv6 networks or just getting your feet wet
+# with ipv6
+
+# Implements RFC5193, section 3.2.2, with precision only down to nanoseconds at best (normalized by date output
+SECSDOTNANO=$(date +%s.%N|sed -e 's/\.0*/\./')
+
+NANOSECONDS=${SECSDOTNANO#*.}
+#Convert from nanoseconds to ntp fractional seconds (I'll call them ticks for convenience)
+# ns * 2**32 ticks/second * 1/1000000000 ns/s = ticks
+NTPTICKS=$(( ($NANOSECONDS<<32) /1000000000))
+
+EPOCHDELTA=2208988800
+SECONDS=${SECSDOTNANO%.*}
+SECONDS=$(($SECONDS+$EPOCHDELTA))
+TIMESTAMP=$(printf "%08X:%08X" $SECONDS $NTPTICKS)
+
+
+#next, get a mac address and convert to eui64
+EUIPAD="FF:FE"
+MAC=$(/sbin/ifconfig|grep HWaddr|grep -v usb|grep -v 00:00:00:00:00:00|head -n 1|awk '{print $NF}')
+FIRSTBYTE=${MAC%%:*}
+FIRSTBYTE=$(printf %02X $((0x$FIRSTBYTE|2)))
+OTHERMANUF=${MAC%%:??:??:??}
+OTHERMANUF=${OTHERMANUF#??:}
+LOWMAC=${MAC#??:??:??:}
+EUI=$FIRSTBYTE:$OTHERMANUF:$EUIPAD:$LOWMAC
+
+#now, to do the SHA, spec doesn't say much about encoding, so we'll just slap the data together the laziest way
+
+PREFIX="fd"$(echo $TIMESTAMP:$EUI|sha1sum|awk '{print $1}'|cut -c 31-)
+PREFIX=$(echo $PREFIX|sed -e 's/\(....\)/\1:/g')
+echo $PREFIX:/48