dhclientv6: Add DHCPv6 support via dhclientbug450326

This adds DHCPv6 support to OpenRC in Linux using dhclient as outlined
by Stuart Longland at <http://stuartl.longlandclan.yi.org/blog/2011/02/15/gentoo-and-dhcpv6/>.
The main place where the new support is added is via a modified copy of
the dhclient.sh script that:

- Renames functions using a 'v6' suffix
- Uses a different pid file
- Uses the '-6' argument when invoking dhclient
- Recognizes new DHCPv6-specific configuration variables with a fallback
  to the DHCP configuration variables.

Additionally:

1. The iproute2 and Linux ifconfig scripts have been ammended to be able
to return IPv6 addresses using new '_get_inet6_address' and
'_get_inet6_addresses' functions.

2. The 'net.lo' init script now has a '_show_address6' function.

3. The documentation in the Linux net.example now contains some DHCPv6
information.

Reported-by: Dustin C. Hatch <admiralnemo@gmail.com>
X-Gentoo-Bug: 150908
X-Gentoo-Bug-URL: https://bugs.gentoo.org/show_bug.cgi?id=150908
Signed-off-by: Robin H. Johnson <robbat2@gentoo.org>

6 files changed, 163 insertions, 6 deletions

diff --git a/doc/net.example.Linux.in b/doc/net.example.Linux.in
index ddfe5e0..4e902b5 100644
--- a/doc/net.example.Linux.in
+++ b/doc/net.example.Linux.in
@@ -484,6 +484,41 @@
 # use any of them.
 
 #-----------------------------------------------------------------------------
+# DHCPv6
+# DHCPv6 can be provided by dhclient
+#
+# dhclient: emerge net-misc/dhcp
+#
+# If you have more than one DHCP client installed, you should probably
+# explicitly use 'dhclient' to use dhclient for both DHCP and DHCPv6,
+# otherwise the default DHCP client will be used.  dhcpcd has some stateless
+# IPv6 autoconfiguration support which may clash with DHCPv6.
+#modules="dhclient" # to select dhclient over dhcpcd
+
+# Regardless of which DHCP client you prefer, you configure them the
+# same way using one of following depending on which interface modules
+# you're using.
+#config_eth0="dhcpv6"
+
+# You can also use both DHCP and DHCPv6 on a dual-stack network:
+#config_eth0="dhcp
+#dhcpv6"
+
+# To pass runtime arguments to dhclient for DHCPv6, you do it similarly to
+# setting runtime arguments for DHCP.  Note that you can set options for
+# DHCPv6 separately or in addition the dhclient arguments for DHCP.
+#dhclientv6_eth0="..." # options for DHCPv6 only
+#dhclient_eth0='..."   # options for DHCP (also for DHCPv6 when no
+#                      # dhclientv6_eth0 is defined)
+
+# GENERIC DHCPv6 OPTIONS
+# Set generic DHCPv6 options just as with generic DHCP options.
+#dhcpv6_eth0="release nodns nontp nonis nogateway nosendhost"
+
+# If no generic DHCPv6 options are set, the default is to fall back to the
+# DHCP generic options.
+
+#-----------------------------------------------------------------------------
 # For APIPA support, emerge net-misc/iputils or net-analyzer/arping
 
 # APIPA is a module that tries to find a free address in the range
diff --git a/init.d/net.lo.in b/init.d/net.lo.in
index 5ea73c7..bf77dff 100644
--- a/init.d/net.lo.in
+++ b/init.d/net.lo.in
@@ -214,6 +214,11 @@ _show_address()
 	einfo "received address $(_get_inet_address "${IFACE}")"
 }
 
+_show_address6()
+{
+	einfo "received address $(_get_inet6_address "${IFACE}")"
+}
+
 # Basically sorts our modules into order and saves the list
 _gen_module_list()
 {
diff --git a/net/Makefile b/net/Makefile
index a03c171..dfa7fcf 100644
--- a/net/Makefile
+++ b/net/Makefile
@@ -13,7 +13,7 @@ SRCS-Linux=	iwconfig.sh.in udhcpc.sh.in
 INC-Linux=	adsl.sh apipa.sh arping.sh bonding.sh br2684ctl.sh bridge.sh \
 		ccwgroup.sh clip.sh ethtool.sh iproute2.sh ifplugd.sh ip6to4.sh \
 		ipppd.sh iwconfig.sh netplugd.sh pppd.sh pump.sh tuntap.sh udhcpc.sh \
-		vlan.sh macvlan.sh ip6rd.sh firewalld.sh
+		vlan.sh macvlan.sh ip6rd.sh firewalld.sh dhclientv6.sh
 
 SRCS-NetBSD= ifwatchd.sh.in
 INC-NetBSD=	ifwatchd.sh
diff --git a/net/dhclientv6.sh b/net/dhclientv6.sh
new file mode 100644
index 0000000..f87ed4d
--- /dev/null
+++ b/net/dhclientv6.sh
@@ -0,0 +1,82 @@
+# Copyright (c) 2007-2008 Roy Marples <roy@marples.name>
+# Released under the 2-clause BSD license.
+
+dhclientv6_depend()
+{
+	after interface
+	program start /sbin/dhclient
+	provide dhcpv6
+}
+
+_config_vars="$_config_vars dhcp dhclient dhcpv6 dhclientv6"
+
+dhclientv6_start()
+{
+	local args= opt= opts= pidfile="/var/run/dhclientv6-${IFACE}.pid"
+	local sendhost=true dconf=
+
+	# Get our options
+	# These options only work in Gentoo, and maybe RedHat
+	eval args=\$dhclientv6_${IFVAR}
+	[ -z "${args}" ] && eval args=\$dhclient_${IFVAR}
+	eval opts=\$dhcpv6_${IFVAR}
+	[ -z "${opts}" ] && opts=${dhcpv6}
+	[ -z "${opts}" ] && eval opts=\$dhcp_${IFVAR}
+	[ -z "${opts}" ] && opts=${dhcp}
+
+	for opt in ${opts}; do
+		case "${opt}" in
+			nodns) args="${args} -e PEER_DNS=no";;
+			nontp) args="${args} -e PEER_NTP=no";;
+			nogateway) args="${args} -e PEER_ROUTERS=no";;
+			nosendhost) sendhost=false;;
+		esac
+	done
+
+	# Add our route metric
+	[ "${metric:-0}" != "0" ] && args="${args} -e IF_METRIC=${metric}"
+
+	if ${sendhost}; then
+		local hname="$(hostname)"
+		if [ "${hname}" != "(none)" -a "${hname}" != "localhost" ]; then
+			dhconf="${dhconf} interface \"${IFACE}\" {"
+			dhconf="${dhconf} send fqdn.fqdn \"${hname}\";"
+			dhconf="${dhconf} send fqdn.encoded on;"
+			dhconf="${dhconf} send fqdn.server-update on;"
+			dhconf="${dhconf} send fqdn.no-client-update on;"
+			dhconf="${dhconf}}"
+		fi
+	fi
+
+	# Bring up DHCP for this interface
+	ebegin "Running dhclient -6"
+	echo "${dhconf}" | start-stop-daemon --start --exec /sbin/dhclient \
+		--pidfile "${pidfile}" \
+		-- -6 ${args} -q -1 -pf "${pidfile}" "${IFACE}"
+	eend $? || return 1
+
+	_show_address6
+	return 0
+}
+
+dhclientv6_stop()
+{
+	local pidfile="/var/run/dhclientv6-${IFACE}.pid" opts=
+	[ ! -f "${pidfile}" ] && return 0
+
+	# Get our options
+	if [ -x /sbin/dhclient ]; then
+		eval opts=\$dhcp_${IFVAR}
+		[ -z "${opts}" ] && opts=${dhcp}
+	fi
+
+	ebegin "Stopping dhclient -6 on ${IFACE}"
+	case " ${opts} " in
+		*" release "*) dhclient -6 -q -r -pf "${pidfile}" "${IFACE}";;
+		*)
+			start-stop-daemon --stop --quiet \
+				--exec /sbin/dhclient --pidfile "${pidfile}"
+			;;
+	esac
+	eend $?
+}
diff --git a/net/ifconfig.sh.Linux.in b/net/ifconfig.sh.Linux.in
index b2203cb..25f1fef 100644
--- a/net/ifconfig.sh.Linux.in
+++ b/net/ifconfig.sh.Linux.in
@@ -86,21 +86,41 @@ _get_inet_address()
 	echo "/$(_netmask2cidr "$1")"
 }
 
-_get_inet_addresses()
+_get_inet6_address()
+{
+	set -- $(LC_ALL=C ifconfig "${IFACE}" |
+	sed -n -e 's/.*\(inet6 addr:\|inet6\) \([^ /]*\)\(\/\| *prefixlen \)\([^ ]*\).*/\2\/\4/p')
+	[ -z "$1" ] && return 1
+
+	echo -n "$1"
+}
+
+_get_addresses_fn()
 {
+	local fn="$1"
 	local iface=${IFACE} i=0
-	local addrs="$(_get_inet_address)"
+	local addrs="$($fn)"
 
 	while true; do
 		local IFACE="${iface}:${i}"
 		_exists || break
-		local addr="$(_get_inet_address)"
+		local addr="$($fn)"
 		[ -n "${addr}" ] && addrs="${addrs}${addrs:+ }${addr}"
 		: $(( i += 1 ))
 	done
 	echo "${addrs}"
 }
 
+_get_inet_addresses()
+{
+	_get_addresses_fn _get_inet_address
+}
+
+_get_inet6_addresses()
+{
+	_get_addresses_fn _get_inet6_address
+}
+
 _cidr2netmask()
 {
 	local cidr="$1" netmask="" done=0 i=0 sum=0 cur=128
diff --git a/net/iproute2.sh b/net/iproute2.sh
index 096e724..ed5750f 100644
--- a/net/iproute2.sh
+++ b/net/iproute2.sh
@@ -84,8 +84,16 @@ _set_mac_address()
 
 _get_inet_addresses()
 {
-	LC_ALL=C ip -family inet addr show "${IFACE}" | \
-	sed -n -e 's/.*inet \([^ ]*\).*/\1/p'
+	local family="$1";
+	if [ -z "$family" ]; then
+		family="inet"
+	fi
+	LC_ALL=C ip -family $family addr show "${IFACE}" | \
+	sed -n -e 's/.*inet6\? \([^ ]*\).*/\1/p'
+}
+
+_get_inet6_addresses() {
+	_get_inet_addresses "inet6"
 }
 
 _get_inet_address()
@@ -95,6 +103,13 @@ _get_inet_address()
 	echo "$1"
 }
 
+_get_inet6_address()
+{
+	set -- $(_get_inet6_addresses)
+	[ $# = "0" ] && return 1
+	echo "$1"
+}
+
 _add_address()
 {
 	if [ "$1" = "127.0.0.1/8" -a "${IFACE}" = "lo" ]; then