dnsmasq: expand 'add_local_hostname' fexibility including FQDN

ref commit 612e2276b4
ref commit ec63e3bf13

'option add_local_hostname' scripted implementation statically assigns
this host in auto generated host file at init. If IFUP or other signals
do not occur, then address changes are not tracked. The script doesn't
apply all the addresses at an interface. This may make logs obscure.
The script only puts the bare host name (maybe not FQDN) in host file,
but if '--exapandhosts' is enabled, then /etc/hosts entries will be
suffixed, and "127.0.0.1 localhost" becomes "localhost.lan".

dnsmasq provides an option to perform this function, but it is rather
greedy. '--interface-name=<name>,<iface>' will assign the name to all
IP on the specified interface (except link local). This is a useful
feature, but some setups depend on the original restrictive behavior.

'option add_local_fqdn' is added to enhance the feature set, but
if not entered or empty string, then it will default to original
option and behavior. This new option has a few settings. At each
increased setting the most detailed name becomes the PTR record:
0 - same as add_local_hostname 0 or disabled
1 - same as add_local_hostname 1
2 - assigns the bare host name to all IP w/ --dnsmasq-interface
3 - assigns the FQDN and host to all IP w/ --dnsmasq-interface
4 - assigns <iface>.<host>.<domain> and above w/ --dnsmasq-nterface

'option add_wan_fqdn' is added to run the same procedure on
inferred WAN intefaces. If an interface has 'config dhcp' and
'option ignore 1' set, then it is considered WAN. The original
option would only run on DHCP serving interfaces.

Signed-off-by: Eric Luehrsen <ericluehrsen@hotmail.com>

package/network/services/dnsmasq/Makefile

@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=dnsmasq
 PKG_VERSION:=2.76
-PKG_RELEASE:=6
+PKG_RELEASE:=7
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.xz
 PKG_SOURCE_URL:=http://thekelleys.org.uk/dnsmasq

package/network/services/dnsmasq/files/dnsmasq.init

@@ -8,6 +8,8 @@ PROG=/usr/sbin/dnsmasq
 
 ADD_LOCAL_DOMAIN=1
 ADD_LOCAL_HOSTNAME=1
+ADD_WAN_FQDN=0
+ADD_LOCAL_FQDN=""
 
 BASECONFIGFILE="/var/etc/dnsmasq.conf"
 BASEHOSTFILE="/tmp/hosts/dhcp"
@@ -293,6 +295,55 @@ dhcp_host_add() {
 	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}"
 }
 
+dhcp_this_host_add() {
+	local net="$1"
+	local ifname="$2"
+	local mode="$3"
+	local routerstub routername ifdashname
+	local lanaddr lanaddr6 lanaddrs6 ulaprefix
+
+	if [ "$mode" -gt 0 ] ; then
+		ifdashname="${ifname//./-}"
+		routerstub="$( md5sum /etc/os-release )"
+		routerstub="router-${routerstub// */}"
+		routername="$( uci_get system @system[0] hostname $routerstub )"
+
+		if [ "$mode" -gt 1 ] ; then
+			if [ "$mode" -gt 2 ] ; then
+				if [ "$mode" -gt 3 ] ; then
+					xappend "--interface-name=$ifdashname.$routername.$DOMAIN,$ifname"
+				fi
+
+				xappend "--interface-name=$routername.$DOMAIN,$ifname"
+			fi
+
+			# All IP addresses discovered by dnsmasq will be labeled (except fe80::)
+			xappend "--interface-name=$routername,$ifname"
+
+		else
+			# This uses a static host file entry for only limited addresses.
+			# Use dnsmasq option "--expandhosts" to enable FQDN on host files.
+			ulaprefix="$(uci_get network @globals[0] ula_prefix)"
+			network_get_ipaddr lanaddr "$net"
+			network_get_ipaddrs6 lanaddrs6 "$net"
+
+			if [ -n "$lanaddr" ] ; then
+				dhcp_domain_add "" "$routername" "$lanaddr"
+			fi
+
+			if [ -n "$ulaprefix" -a -n "$lanaddrs6" ] ; then
+				for lanaddr6 in $lanaddrs6 ; do
+					case "$lanaddr6" in
+					"${ulaprefix%%:/*}"*)
+							dhcp_domain_add "" "$routername" "$lanaddr6"
+							;;
+					esac
+				done
+			fi
+		fi
+	fi
+}
+
 dhcp_tag_add() {
 	local cfg="$1"
 
@@ -363,7 +414,11 @@ dhcp_add() {
 		DNS_SERVERS="$DNS_SERVERS $dnsserver"
 	}
 
-	append_bool "$cfg" ignore "--no-dhcp-interface=$ifname" && return 0
+	append_bool "$cfg" ignore "--no-dhcp-interface=$ifname" && {
+		# Many ISP do not have useful names for DHCP customers (your WAN).
+		dhcp_this_host_add "$net" "$ifname" "$ADD_WAN_FQDN"
+		return 0
+	}
 
 	# Do not support non-static interfaces for now
 	[ static = "$proto" ] || return 0
@@ -381,6 +436,9 @@ dhcp_add() {
 	config_get options "$cfg" options
 	config_get_bool dynamicdhcp "$cfg" dynamicdhcp 1
 
+	# Put the router host name on this DHCP served interface address(es)
+	dhcp_this_host_add "$net" "$ifname" "$ADD_LOCAL_FQDN"
+
 	leasetime="${leasetime:-12h}"
 	start="$(dhcp_calc "${start:-100}")"
 	limit="${limit:-150}"
@@ -605,6 +663,13 @@ dnsmasq_start()
 
 	config_get_bool ADD_LOCAL_DOMAIN "$cfg" add_local_domain 1
 	config_get_bool ADD_LOCAL_HOSTNAME "$cfg" add_local_hostname 1
+	config_get ADD_LOCAL_FQDN "$cfg" add_local_fqdn ""
+	config_get ADD_WAN_FQDN "$cfg" add_wan_fqdn 0
+
+	if [ -z "$ADD_LOCAL_FQDN" ] ; then
+		# maintain support for previous UCI
+		ADD_LOCAL_FQDN="$ADD_LOCAL_HOSTNAME"
+	fi
 
 	config_get_bool readethers "$cfg" readethers
 	[ "$readethers" = "1" -a \! -e "/etc/ethers" ] && touch /etc/ethers
@@ -702,27 +767,6 @@ dnsmasq_start()
 	config_foreach filter_dnsmasq hostrecord dhcp_hostrecord_add "$cfg"
 	config_foreach filter_dnsmasq relay dhcp_relay_add "$cfg"
 
-	# add own hostname
-	[ $ADD_LOCAL_HOSTNAME -eq 1 ] && {
-		local lanaddr lanaddr6
-		local ulaprefix="$(uci_get network @globals[0] ula_prefix)"
-		local hostname="$(uci_get system @system[0] hostname Lede)"
-
-		network_get_ipaddr lanaddr "lan" && {
-			dhcp_domain_add "" "$hostname" "$lanaddr"
-		}
-
-		[ -n "$ulaprefix" ] && network_get_ipaddrs6 lanaddr6 "lan" && {
-			for lanaddr6 in $lanaddr6; do
-				case "$lanaddr6" in
-					"${ulaprefix%%:/*}"*)
-						dhcp_domain_add "" "$hostname" "$lanaddr6"
-					;;
-				esac
-			done
-		}
-	}
-
 	echo >> $CONFIGFILE_TMP
 	config_foreach filter_dnsmasq srvhost dhcp_srv_add "$cfg"
 	config_foreach filter_dnsmasq mxhost dhcp_mx_add "$cfg"