resolvconf

#
# Script fragment to make dhclient supply nameserver information to resolvconf
#

# Tips:
# * Be careful about changing the environment since this is sourced
# * This script fragment uses bash features
# * As of isc-dhcp-client 4.2 the "reason" (for running the script) can be one of the following.
#   (Listed on man page:) MEDIUM(0) PREINIT(0)  BOUND(M)  RENEW(M)  REBIND(M)  REBOOT(M)         EXPIRE(D)  FAIL(D) RELEASE(D)  STOP(D) NBI(-) TIMEOUT(M)
#   (Also used in master script:)                                                                                                                         ARPCHECK(0), ARPSEND(0)
#   (Also used in master script:)   PREINIT6(0) BOUND6(M) RENEW6(M) REBIND6(M)        DEPREF6(0) EXPIRE6(D)         RELEASE6(D) STOP6(D)
#   (0) = master script does not run make_resolv_conf
#   (M) = master script runs make_resolv_conf
#   (D) = master script downs interface
#   (-) = master script does nothing with this

if [ -x /sbin/resolvconf ] ; then
	# For safety, first undefine the nasty default make_resolv_conf()
	make_resolv_conf() { : ; }
	case "$reason" in
	  BOUND|RENEW|REBIND|REBOOT|TIMEOUT)
		# Define a resolvconf-compatible m_r_c() function
		# It gets run later (or, in the TIMEOUT case, MAY get run later)
		make_resolv_conf() {
			local R
			local N
			R=""
			if [ "$new_domain_name_servers" ] && [ "$new_domain_name" ] ; then
				R="${R}domain $new_domain_name
"
			fi
			if [ "$new_domain_name_servers" ] && [ "$new_domain_search" ] ; then
				R="${R}search $new_domain_search
"
			fi
			for N in $new_domain_name_servers ; do
				R="${R}nameserver $N
"
			done
			[ ! "$interface" ] || echo -n "$R" | /sbin/resolvconf -a "${interface}.dhclient"
		}
		;;
	  BOUND6|RENEW6|REBIND6)
		# Define a resolvconf-compatible m_r_c() function
		# It gets run later (or, in the TIMEOUT case, MAY get run later)
		make_resolv_conf() {
			local R
			local N
			local N_LOW
			local ZONE_ID
			R=""
			if [ "$new_dhcp6_name_servers" ] && [ "$new_dhcp6_domain_search" ] ; then
				R="${R}search $new_dhcp6_domain_search
"
			fi
			for N in $new_dhcp6_name_servers ; do

				# If the nameserver has a link-local address
				# then add a zone ID (interface name) to it.
				N_LOW="$(echo "$N" | tr '[:upper:]' '[:lower:]')"
				if expr "$N_LOW" : ^fe80:: >/dev/null ; then
					ZONE_ID="%$interface"
				else
					ZONE_ID=""
				fi
				R="${R}nameserver $N$ZONE_ID
"
			done
			[ ! "$interface" ] || echo -n "$R" | /sbin/resolvconf -a "${interface}.ip6.dhclient"
		}
		;;
	  EXPIRE|FAIL|RELEASE|STOP)
		# Delete resolv.conf info 
		[ ! "$interface" ] || /sbin/resolvconf -d "${interface}.dhclient"
		;;
	  EXPIRE6|RELEASE6|STOP6)
		# Delete resolv.conf info 
		[ ! "$interface" ] || /sbin/resolvconf -d "${interface}.ip6.dhclient"
		;;
	esac
fi