dnsmasq: make DHCPv6 viable for standalone dnsmasq install

dnsmasq has sufficient services to meet the needs of DHCP
and RA with IP6 for single router router users. This is
the most common use for consumer routers. Its reenforced
as most ISP tend to only DHCP-PD /64. dnsmasq has year
over year demonstrated great flexibility in its option
set, and support for off-standard DHCP clients.

odhcpd has enhanced capabilities focused on IP6 such
as DHCP/RA relay and NDP proxy. However, it is not as
flexible in its option set. odhcpd is not as forgiving
with off-standard DHCP clients. Some points may represent
a long term TODO list, but it is the state currently.

These changes make any such combination possible. Already
odhcpd can be set as the main dhcp server. Now odhcpd
can be removed or disabled and dnsmasq will take over
if DHCPv6 compiled in. The existing DHCPv6 and RA UCI
are translated into dnsmasq.conf. The changes focus on
'--dhcp-range', '--dhcp-host', and '--dhcp-options'.

DHCP host ID is least 16 bits [::1000-::FFFF], but
leaves low range for typical infrastructure assignments.
dnsmasq accepts DHCPv6 options in the tranditional
'--dhcp-option' put they must be prefixed 'option6:'.
dnsmasq will also discover SLAAC DNS entries from DHCPv4
clients MAC, and confirm with a ping at least renew.

Long term TODO include improving use of dnsmasq relay
options for DHCPv4 and DHCPv6 in parallel. It would also
be possible to preconfigure DHCP-PD in host-with-options
records for fixed infrastructure.

Signed-off-by: Eric Luehrsen <ericluehrsen@hotmail.com>
[Jo-Philipp Wich: emit proper IPv6 hostid format in dhcp-host directive]
Signed-off-by: Jo-Philipp Wich <jo@mein.io>
This commit is contained in:
Eric Luehrsen 2016-12-22 13:20:25 -05:00 committed by Jo-Philipp Wich
parent 1b4e3eda1b
commit 9525743c07
2 changed files with 152 additions and 29 deletions

View file

@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
PKG_NAME:=dnsmasq PKG_NAME:=dnsmasq
PKG_VERSION:=2.76 PKG_VERSION:=2.76
PKG_RELEASE:=7 PKG_RELEASE:=8
PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.xz PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.xz
PKG_SOURCE_URL:=http://thekelleys.org.uk/dnsmasq PKG_SOURCE_URL:=http://thekelleys.org.uk/dnsmasq

View file

@ -18,6 +18,8 @@ TRUSTANCHORSFILE="/usr/share/dnsmasq/trust-anchors.conf"
TIMEVALIDFILE="/var/state/dnsmasqsec" TIMEVALIDFILE="/var/state/dnsmasqsec"
BASEDHCPSTAMPFILE="/var/run/dnsmasq" BASEDHCPSTAMPFILE="/var/run/dnsmasq"
DNSMASQ_DHCP_VER=4
xappend() { xappend() {
local value="$1" local value="$1"
@ -182,6 +184,7 @@ dhcp_remoteid_add() {
} }
dhcp_circuitid_add() { dhcp_circuitid_add() {
# TODO: DHCPV6 does not have circuitid; catch "option6:"
local cfg="$1" local cfg="$1"
config_get networkid "$cfg" networkid config_get networkid "$cfg" networkid
@ -214,6 +217,7 @@ dhcp_userclass_add() {
} }
dhcp_vendorclass_add() { dhcp_vendorclass_add() {
# TODO: DHCPV6 vendor class has stricter definitions; catch? fixup?
local cfg="$1" local cfg="$1"
config_get networkid "$cfg" networkid config_get networkid "$cfg" networkid
@ -247,6 +251,7 @@ dhcp_match_add() {
dhcp_host_add() { dhcp_host_add() {
local cfg="$1" local cfg="$1"
local hosttag nametime addrs
config_get_bool force "$cfg" force 0 config_get_bool force "$cfg" force 0
@ -258,7 +263,9 @@ dhcp_host_add() {
config_get name "$cfg" name config_get name "$cfg" name
config_get ip "$cfg" ip config_get ip "$cfg" ip
[ -n "$ip" -o -n "$name" ] || return 0 config_get hostid "$cfg" hostid
[ -n "$ip" -o -n "$name" -o -n "$hostid" ] || return 0
config_get_bool dns "$cfg" dns 0 config_get_bool dns "$cfg" dns 0
[ "$dns" = "1" -a -n "$ip" -a -n "$name" ] && { [ "$dns" = "1" -a -n "$ip" -a -n "$name" ] && {
@ -266,33 +273,47 @@ dhcp_host_add() {
} }
config_get mac "$cfg" mac config_get mac "$cfg" mac
config_get duid "$cfg" duid
config_get tag "$cfg" tag
if [ -n "$mac" ]; then if [ -n "$mac" ]; then
# --dhcp-host=00:20:e0:3b:13:af,192.168.0.199,lap # --dhcp-host=00:20:e0:3b:13:af,192.168.0.199,lap
# many MAC are possible to track a laptop ON/OFF dock
macs="" macs=""
for m in $mac; do append macs "$m" ","; done for m in $mac; do append macs "$m" ","; done
else fi
# --dhcp-host=lap,192.168.0.199
if [ $DNSMASQ_DHCP_VER -eq 6 -a -n "$duid" ]; then
# --dhcp-host=id:00:03:00:01:12:00:00:01:02:03,[::beef],lap
# one (virtual) machine gets one DUID per RFC3315
duids="id:${duid// */}"
fi
if [ -z "$macs" -a -z "$duids" ]; then
# --dhcp-host=lap,192.168.0.199,[::beef]
[ -n "$name" ] || return 0 [ -n "$name" ] || return 0
macs="$name" macs="$name"
name="" name=""
fi fi
config_get tag "$cfg" tag if [ -n "$hostid" ]; then
if [ "$DHCPv6CAPABLE" -eq 1 ]; then
config_get duid "$cfg" duid
config_get hostid "$cfg" hostid
if [ -n "$hostid" ]; then
hex_to_hostid hostid "$hostid" hex_to_hostid hostid "$hostid"
fi
fi fi
config_get_bool broadcast "$cfg" broadcast 0 config_get_bool broadcast "$cfg" broadcast 0
[ "$broadcast" = "0" ] && broadcast=
config_get leasetime "$cfg" leasetime config_get leasetime "$cfg" leasetime
xappend "--dhcp-host=$macs${duid:+,id:$duid}${networkid:+,net:$networkid}${broadcast:+,set:needs-broadcast}${tag:+,set:$tag}${ip:+,$ip${hostid:+,[::$hostid]}}${name:+,$name}${leasetime:+,$leasetime}" [ "$broadcast" = "0" ] && broadcast= || broadcast=",set:needs-broadcast"
hosttag="${networkid:+,set:${networkid}}${tag:+,set:${tag}}$broadcast"
nametime="${name:+,$name}${leasetime:+,$leasetime}"
if [ $DNSMASQ_DHCP_VER -eq 6 ]; then
addrs="${ip:+,$ip}${hostid:+,[::$hostid]}"
xappend "--dhcp-host=$macs${duids:+,$duids}$hosttag$addrs$nametime"
else
xappend "--dhcp-host=$macs$hosttag${ip:+,$ip}$nametime"
fi
} }
dhcp_this_host_add() { dhcp_this_host_add() {
@ -345,6 +366,7 @@ dhcp_this_host_add() {
} }
dhcp_tag_add() { dhcp_tag_add() {
# NOTE: dnsmasq has explicit "option6:" prefix for DHCPv6 so no collisions
local cfg="$1" local cfg="$1"
tag="$cfg" tag="$cfg"
@ -375,6 +397,7 @@ dhcp_mac_add() {
} }
dhcp_boot_add() { dhcp_boot_add() {
# TODO: BOOTURL is different between DHCPv4 and DHCPv6
local cfg="$1" local cfg="$1"
config_get networkid "$cfg" networkid config_get networkid "$cfg" networkid
@ -397,12 +420,12 @@ dhcp_boot_add() {
dhcp_add() { dhcp_add() {
local cfg="$1" local cfg="$1"
local dhcp6range="::"
local nettag
config_get net "$cfg" interface config_get net "$cfg" interface
[ -n "$net" ] || return 0 [ -n "$net" ] || return 0
config_get dhcpv4 "$cfg" dhcpv4
[ "$dhcpv4" != "disabled" ] || return 0
config_get networkid "$cfg" networkid config_get networkid "$cfg" networkid
[ -n "$networkid" ] || networkid="$net" [ -n "$networkid" ] || networkid="$net"
@ -430,27 +453,92 @@ dhcp_add() {
config_get_bool force "$cfg" force 0 config_get_bool force "$cfg" force 0
[ $force -gt 0 ] || dhcp_check "$ifname" || return 0 [ $force -gt 0 ] || dhcp_check "$ifname" || return 0
config_get start "$cfg" start config_get start "$cfg" start 100
config_get limit "$cfg" limit config_get limit "$cfg" limit 150
config_get leasetime "$cfg" leasetime config_get leasetime "$cfg" leasetime 12h
config_get options "$cfg" options config_get options "$cfg" options
config_get_bool dynamicdhcp "$cfg" dynamicdhcp 1 config_get_bool dynamicdhcp "$cfg" dynamicdhcp 1
config_get dhcpv4 "$cfg" dhcpv4
config_get dhcpv6 "$cfg" dhcpv6
config_get ra "$cfg" ra
config_get ra_management "$cfg" ra_management
config_get ra_preference "$cfg" ra_preference
# Put the router host name on this DHCP served interface address(es) # Put the router host name on this DHCP served interface address(es)
dhcp_this_host_add "$net" "$ifname" "$ADD_LOCAL_FQDN" dhcp_this_host_add "$net" "$ifname" "$ADD_LOCAL_FQDN"
leasetime="${leasetime:-12h}" start="$( dhcp_calc "$start" )"
start="$(dhcp_calc "${start:-100}")" nettag="${networkid:+set:${networkid},}"
limit="${limit:-150}"
[ "$limit" -gt 0 ] && limit=$((limit-1)) if [ "$limit" -gt 0 ] ; then
limit=$((limit-1))
fi
eval "$(ipcalc.sh "${subnet%%/*}" $netmask $start $limit)" eval "$(ipcalc.sh "${subnet%%/*}" $netmask $start $limit)"
if [ "$dynamicdhcp" = "0" ]; then END="static"; fi
xappend "--dhcp-range=$networkid,$START,$END,$NETMASK,$leasetime${options:+ $options}" if [ "$dynamicdhcp" = "0" ] ; then
END="static"
dhcp6range="::,static"
else
dhcp6range="::1000,::ffff"
fi
if [ "$dhcpv4" != "disabled" ] ; then
xappend "--dhcp-range=$nettag$START,$END,$NETMASK,$leasetime${options:+ $options}"
fi
if [ $DNSMASQ_DHCP_VER -eq 6 -a "$ra" = "server" ] ; then
# Note: dnsmasq cannot just be a DHCPv6 server (all-in-1)
# and let some other machine(s) send RA pointing to it.
case $ra_preference in
*high*)
xappend "--ra-param=$ifname,high,0,7200"
;;
*low*)
xappend "--ra-param=$ifname,low,0,7200"
;;
*)
# Send UNSOLICITED RA at default interval and live for 2 hours.
# TODO: convert flexible lease time into route life time (only seconds).
xappend "--ra-param=$ifname,0,7200"
;;
esac
if [ "$dhcpv6" = "disabled" ] ; then
ra_management="3"
fi
case $ra_management in
0)
# SLACC with DCHP for extended options
xappend "--dhcp-range=$nettag::,constructor:$ifname,ra-stateless,ra-names"
;;
2)
# DHCP address and RA only for management redirection
xappend "--dhcp-range=$nettag$dhcp6range,constructor:$ifname,$leasetime"
;;
3)
# SLAAC only but dnsmasq attempts to link HOSTNAME, DHCPv4 MAC, and SLAAC
xappend "--dhcp-range=$nettag::,constructor:$ifname,ra-only,ra-names"
;;
*)
# SLAAC and full DHCP
xappend "--dhcp-range=$nettag$dhcp6range,constructor:$ifname,slaac,ra-names,$leasetime"
;;
esac
fi
dhcp_option_add "$cfg" "$networkid" dhcp_option_add "$cfg" "$networkid"
} }
dhcp_option_add() { dhcp_option_add() {
# NOTE: dnsmasq has explicit "option6:" prefix for DHCPv6 so no collisions
local cfg="$1" local cfg="$1"
local networkid="$2" local networkid="$2"
local force="$3" local force="$3"
@ -605,6 +693,32 @@ dnsmasq_start()
$PROG --version | grep -osqE "^Compile time options:.* DHCPv6( |$)" && DHCPv6CAPABLE=1 || DHCPv6CAPABLE=0 $PROG --version | grep -osqE "^Compile time options:.* DHCPv6( |$)" && DHCPv6CAPABLE=1 || DHCPv6CAPABLE=0
if [ -x /usr/sbin/odhcpd -a -x /etc/init.d/odhcpd ] ; then
local odhcpd_is_main odhcpd_is_enabled
config_get odhcpd_is_main odhcpd maindhcp
/etc/init.d/odhcpd enabled && odhcpd_is_enabled=1 || odhcpd_is_enabled=0
if [ "$odhcpd_is_enabled" -eq 0 -a "$DHCPv6CAPABLE" -eq 1 ] ; then
# DHCP V4 and V6 in DNSMASQ
DNSMASQ_DHCP_VER=6
elif [ "$odhcpd_is_main" -gt 0 ] ; then
# ODHCPD is doing it all
DNSMASQ_DHCP_VER=0
else
# You have ODHCPD but use DNSMASQ for DHCPV4
DNSMASQ_DHCP_VER=4
fi
elif [ "$DHCPv6CAPABLE" -eq 1 ] ; then
# DHCP V4 and V6 in DNSMASQ
DNSMASQ_DHCP_VER=6
else
DNSMASQ_DHCP_VER=4
fi
append_bool "$cfg" authoritative "--dhcp-authoritative" append_bool "$cfg" authoritative "--dhcp-authoritative"
append_bool "$cfg" nodaemon "--no-daemon" append_bool "$cfg" nodaemon "--no-daemon"
append_bool "$cfg" domainneeded "--domain-needed" append_bool "$cfg" domainneeded "--domain-needed"
@ -772,11 +886,20 @@ dnsmasq_start()
config_foreach filter_dnsmasq mxhost dhcp_mx_add "$cfg" config_foreach filter_dnsmasq mxhost dhcp_mx_add "$cfg"
echo >> $CONFIGFILE_TMP echo >> $CONFIGFILE_TMP
config_get odhcpd_is_active odhcpd maindhcp
if [ "$odhcpd_is_active" != "1" ]; then if [ "$DNSMASQ_DHCP_VER" -gt 4 ] ; then
config_foreach filter_dnsmasq dhcp dhcp_add "$cfg" # Enable RA feature for when/if it is constructed,
# and RA is selected per interface pool (RA, DHCP, or both),
# but no one (should) want RA broadcast in syslog
config_foreach dhcp_add dhcp
xappend "--enable-ra"
xappend "--quiet-ra"
elif [ "$DNSMASQ_DHCP_VER" -gt 0 ] ; then
config_foreach dhcp_add dhcp
fi fi
echo >> $CONFIGFILE_TMP echo >> $CONFIGFILE_TMP
config_foreach filter_dnsmasq cname dhcp_cname_add "$cfg" config_foreach filter_dnsmasq cname dhcp_cname_add "$cfg"
echo >> $CONFIGFILE_TMP echo >> $CONFIGFILE_TMP